Molecular biology is the study of biology at a molecular level. The field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry. Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interactions between DNA, RNA and protein biosynthesis and learning how these interactions are regulated.
Writing in Nature, William Astbury described molecular biology as:
"... not so much a technique as an approach, an approach from the viewpoint of the so-called basic sciences with the leading idea of searching below the large-scale manifestations of classical biology for the corresponding molecular plan. It is concerned particularly with the forms of biological molecules and ..... is predominantly three-dimensional and structural - which does not mean, however, that it is merely a refinement of morphology - it must at the same time inquire into genesis and function.
Saturday, December 19, 2009
Microorganism
A microorganism (also can be spelled as micro organism) or microbe is an organism that is microscopic (too small to be seen by the naked human eye). The study of microorganisms is called microbiology, a subject that began with Anton van Leeuwenhoek's discovery of microorganisms in 1675, using a microscope of his own design.
Microorganisms are incredibly diverse and include bacteria, fungi, archaea, and protists, as well as some microscopic plants and animals such as plankton, and popularly-known animals such as the planarian and the amoeba. They do not include viruses and prions, which are generally classified as non-living. Most microorganisms are single-celled, or unicellular, but some multicellular organisms are microscopic, while some unicellular protists, and a bacteria called Thiomargarita namibiensis are visible to the naked eye.
Microorganisms live in all parts of the biosphere where there is liquid water, including hot springs, on the ocean floor, high in the atmosphere and deep inside rocks within the Earth's crust. Microorganisms are critical to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a vital part of the nitrogen cycle, and recent studies indicate that airborne microbes may play a role in precipitation and weather.
Microbes are also exploited by people in biotechnology, both in traditional food and beverage preparation, as well as modern technologies based on genetic engineering. However, pathogenic microbes are harmful, since they invade and grow within other organisms, causing diseases that kill millions of people, other animals, and plants.
Microorganisms are incredibly diverse and include bacteria, fungi, archaea, and protists, as well as some microscopic plants and animals such as plankton, and popularly-known animals such as the planarian and the amoeba. They do not include viruses and prions, which are generally classified as non-living. Most microorganisms are single-celled, or unicellular, but some multicellular organisms are microscopic, while some unicellular protists, and a bacteria called Thiomargarita namibiensis are visible to the naked eye.
Microorganisms live in all parts of the biosphere where there is liquid water, including hot springs, on the ocean floor, high in the atmosphere and deep inside rocks within the Earth's crust. Microorganisms are critical to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a vital part of the nitrogen cycle, and recent studies indicate that airborne microbes may play a role in precipitation and weather.
Microbes are also exploited by people in biotechnology, both in traditional food and beverage preparation, as well as modern technologies based on genetic engineering. However, pathogenic microbes are harmful, since they invade and grow within other organisms, causing diseases that kill millions of people, other animals, and plants.
Animals
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile - they can move spontaneously and independently. Animals are heterotrophs - they are dependent on other organisms (e.g. plants) for sustenance.
Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.
Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.
Anatomy
Anatomy (from the Greek ἀνατομία anatomia, from ἀνατέμνειν ana: separate, apart from, and temnein, to cut up, cut open) is a branch of biology that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy (zootomy) and plant anatomy (phytotomy). In some of its facets anatomy is closely related to embryology, comparative anatomy and comparative embryology, through common roots in evolution.
Anatomy is subdivided into gross anatomy (or macroscopic anatomy) and microscopic anatomy. Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by unaided vision. Microscopic anatomy is the study of minute anatomical structures assisted with microscopes, which includes histology (the study of the organisation of tissues),and cytology (the study of cells).
The history of anatomy has been characterized, over time, by a continually developing understanding of the functions of organs and structures in the body. Methods have also advanced dramatically, advancing from examination of animals through dissection of cadavers (dead human bodies) to technologically complex techniques developed in the 20th century.
Anatomy is subdivided into gross anatomy (or macroscopic anatomy) and microscopic anatomy. Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by unaided vision. Microscopic anatomy is the study of minute anatomical structures assisted with microscopes, which includes histology (the study of the organisation of tissues),and cytology (the study of cells).
The history of anatomy has been characterized, over time, by a continually developing understanding of the functions of organs and structures in the body. Methods have also advanced dramatically, advancing from examination of animals through dissection of cadavers (dead human bodies) to technologically complex techniques developed in the 20th century.
Saturday, November 21, 2009
Oxygen Catastrophe
The Oxygen Catastrophe was a massive environmental change believed to have happened during the Siderian period at the beginning of the Paleoproterozoic era, about 2.4 billion years ago. It is also called the Oxygen Crisis, Oxygen Revolution or The Great Oxidation.
When evolving life forms developed oxyphotosynthesis about 2.7 billion years ago, molecular oxygen was produced in large quantities. The plentiful oxygen eventually caused an ecological crisis, as oxygen was toxic to the anaerobic organisms living at the time.
However, it also provided a new opportunity. Despite recycling, life had remained energetically limited until the widespread availability of oxygen. This breakthrough in metabolic evolution greatly increased the free energy supply to living organisms, having a truly global environmental impactOxygen CatastropheOxygen Catastrophe
When evolving life forms developed oxyphotosynthesis about 2.7 billion years ago, molecular oxygen was produced in large quantities. The plentiful oxygen eventually caused an ecological crisis, as oxygen was toxic to the anaerobic organisms living at the time.
However, it also provided a new opportunity. Despite recycling, life had remained energetically limited until the widespread availability of oxygen. This breakthrough in metabolic evolution greatly increased the free energy supply to living organisms, having a truly global environmental impactOxygen CatastropheOxygen Catastrophe
Photosynthetic reaction centre
A photosynthetic reaction center is a complex of three proteins that is the site where molecular excitations originating from sunlight are transformed into a series of electron-transfer reactions. The reaction center proteins bind functional co-factors, chromophores or pigments such as chlorophyll and pheophytin molecules. These absorb light, promoting an electron to a higher energy level within a pigment. The free energy created is used to reduce a chain of electron acceptors which have subsequently lowered redox-potentials, and is critical for the production of chemical energy during photosynthesis.
Reaction centers are present in all green plants and in many bacteria and algae. Green plants have two reaction centers known as photosystem I and photosystem II and the structures of these centres are complex, involving a multisubunit protein. The reaction centre found in Rhodopseudomonas bacteria is currently better understood since it has fewer proteins than the examples in green plants.
Reaction centers are present in all green plants and in many bacteria and algae. Green plants have two reaction centers known as photosystem I and photosystem II and the structures of these centres are complex, involving a multisubunit protein. The reaction centre found in Rhodopseudomonas bacteria is currently better understood since it has fewer proteins than the examples in green plants.
In algae and bacteria
Algae come in multiple forms from multicellular organisms like kelp, to microscopic, single-cell organisms. Although they are not as complex as land plants, the biochemical process of photosynthesis is the same. Very much like plants, algae have chloroplasts and chlorophyll, but various accessory pigments are present in some algae such as phycocyanin, carotenes, and xanthophylls in green algae and phycoerythrin in red algae (rhodophytes), resulting in a wide variety of colors. Brown algae and diatoms contain fucoxanthol as their primary pigment. All algae produce oxygen, and many are autotrophic. However, some are heterotrophic, relying on materials produced by other organisms. For example, in coral reefs, there is a mutualistic relationship between zooxanthellae and the coral polyps.
Photosynthetic bacteria do not have chloroplasts (or any membrane-bound organelles). Instead, photosynthesis takes place directly within the cell. Cyanobacteria contain thylakoid membranes very similar to those in chloroplasts and are the only prokaryotes that perform oxygen-generating photosynthesis. In fact, chloroplasts are now considered to have evolved from an endosymbiotic bacterium, which was also an ancestor of and later gave rise to cyanobacterium. The other photosynthetic bacteria have a variety of different pigments, called bacteriochlorophylls, and do not produce oxygen. Some bacteria, such as Chromatium, oxidize hydrogen sulfide instead of water for photosynthesis, producing sulfur as waste.
Photosynthetic bacteria do not have chloroplasts (or any membrane-bound organelles). Instead, photosynthesis takes place directly within the cell. Cyanobacteria contain thylakoid membranes very similar to those in chloroplasts and are the only prokaryotes that perform oxygen-generating photosynthesis. In fact, chloroplasts are now considered to have evolved from an endosymbiotic bacterium, which was also an ancestor of and later gave rise to cyanobacterium. The other photosynthetic bacteria have a variety of different pigments, called bacteriochlorophylls, and do not produce oxygen. Some bacteria, such as Chromatium, oxidize hydrogen sulfide instead of water for photosynthesis, producing sulfur as waste.
Microscopy
Microscopy mi·cros·co·py (Pronunciation[mahy-kros-kuh-pee, mahy-kruh-skoh-pee]) is the technical field of using microscopes to view samples or objects. There are three well-known branches of microscopy, optical, electron and scanning probe microscopy.
Optical and electron microscopy involve the diffraction, reflection, or refraction of electromagnetic radiation incident upon the subject of study, and the subsequent collection of this scattered radiation in order to build up an image. This process may be carried out by wide field irradiation of the sample (for example standard light microscopy and transmission electron microscopy) or by scanning of a fine beam over the sample (for example confocal microscopy and scanning electron microscopy). Scanning probe microscopy involves the interaction of a scanning probe with the surface or object of interest. The development of microscopy revolutionized biology and remains an essential tool in that science, along with many others.
Optical and electron microscopy involve the diffraction, reflection, or refraction of electromagnetic radiation incident upon the subject of study, and the subsequent collection of this scattered radiation in order to build up an image. This process may be carried out by wide field irradiation of the sample (for example standard light microscopy and transmission electron microscopy) or by scanning of a fine beam over the sample (for example confocal microscopy and scanning electron microscopy). Scanning probe microscopy involves the interaction of a scanning probe with the surface or object of interest. The development of microscopy revolutionized biology and remains an essential tool in that science, along with many others.
Diatom
Diatoms are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons (e.g. Fragillaria), fans (Meridion), zigzags (Tabellaria), or stellate colonies (Asterionella). A characteristic feature of diatom cells is that they are encased within a unique cell wall made of silica (hydrated silicon dioxide) called a frustule. These frustules show a wide diversity in form, some quite beautiful and ornate, but usually consist of two asymmetrical sides with a split between them, hence the group name. Fossil evidence suggests that they originated during, or before, the early Jurassic Period. Diatom communities are a popular tool for monitoring environmental conditions, past and present, and are commonly used in studies of water quality.
Phycocyanin
Phycocyanin is a pigment from the light-harvesting phycobiliprotein family, along with allophycocyanin and phycoerythrin. It is an accessory pigment to chlorophyll. All phycobiliproteins are water soluble and therefore cannot exist within the membrane like carotenoids, but aggregate forming clusters that adhere to the membrane called phycobilisomes. Phycocyanin absorbs orange and red light, particularly near 620 nm (depending on which specific type it is), and emits fluorescence at about 650 nm (also depending on which type it is). Allophycocyanin absorbs and emits at longer wavelengths than Phycocyanin C or Phycocyanin R. Phycocyanins are found in Cyanobacteria (previously called blue-green algae). Phycobiliproteins have fluorescent properties that are used in immunoassay kits. Phycocyanin is from the Greek phyco meaning “algae” and cyanin is from the English word “cyan", which is derived from the Greek “kyanos" and means blue-green. The product Phycocyanin, produced by Spirulina, is used in the food and beverage industry as the colouring agent 'Lima Blue' and is found in sweets and ice cream.
Wednesday, July 8, 2009
Mesothelioma Lung Cancer
Mesothelioma and lung cancer are both serious illnesses, but they are not the same. Mesothelioma – sometimes called “asbestos lung cancer” – is really not a form of lung cancer because it does not develop in the tissue of the lungs. Instead, it is a cancer of the lining that surrounds the lung (the “pleura”).
Mesothelioma is caused almost exclusively by asbestos exposure. It is considered a “signature disease” for asbestos exposure, which means that, if you have mesothelioma, it can be assumed that you had exposure to asbestos at some point in your life. Smoking does not cause mesothelioma.
Lung cancer can be caused by asbestos exposure; it can also be caused by smoking. In fact, someone who smokes and was exposed to asbestos has a much higher risk of getting lung cancer. See Asbestos and Smoking.
Mesothelioma is caused almost exclusively by asbestos exposure. It is considered a “signature disease” for asbestos exposure, which means that, if you have mesothelioma, it can be assumed that you had exposure to asbestos at some point in your life. Smoking does not cause mesothelioma.
Lung cancer can be caused by asbestos exposure; it can also be caused by smoking. In fact, someone who smokes and was exposed to asbestos has a much higher risk of getting lung cancer. See Asbestos and Smoking.
Causes Of Cancer
Cells are the building blocks of living things. Cancer grows out of normal cells in the body. Normal cells multiply when the body needs them, and die when the body doesn't need them. Cancer appears to occur when the growth of cells in the body is out of control and cells divide too quickly. It can also occur when cells “forget” how to die.
There are many different kinds of cancers. Cancer can develop in almost any organ or tissue, such as the lung, colon, breast, skin, bones, or nerve tissue.
There are many causes of cancers, including:
- Benzene and other chemicals
- Certain poisonous mushrooms and a type of poison that can grow on peanut plants (aflatoxins)
- Certain viruses
- Radiation
- Sunlight
- Tobacco
However, the cause of many cancers remains unknown.
The most common cause of cancer-related death is lung cancer.
The three most common cancers in men in the United States are:
In women in the U.S., the three most common cancers are:
- Breast cancer
- Colon cancer
- Lung cancer
Some cancers are more common in certain parts of the world. For example, in Japan, there are many cases of gastric cancer, but in the U.S. this type of cancer is pretty rare. Differences in diet may play a role.
Some other types of cancers include:
Cancer Exams and Tests
Like symptoms, the signs of cancer vary based on the type and location of the tumor. Common tests include the following:
- Biopsy of the tumor
- Blood chemistries
- Bone marrow biopsy (for lymphoma or leukemia)
- Chest x-ray
- Complete blood count (CBC)
- CT scan
Most cancers are diagnosed by biopsy. Depending on the location of the tumor, the biopsy may be a simple procedure or a serious operation. Most patients with cancer have CT scans to determine the exact location and size of the tumor or tumors.
A cancer diagnosis is difficult to cope with. It is important, however, that you discuss the type, size, and location of the cancer with your doctor when you are diagnosed. You also will want to ask about treatment options, along with their benefits and risks.
It's a good idea to have someone with you at the doctor's office to help you get through the diagnosis. If you have trouble asking questions after hearing about your diagnosis, the person you bring with you can ask them for you.
Treatment and Prevention of Cancer
Treatment also varies based on the type of cancer and its stage. The stage of a cancer refers to how much it has grown and whether the tumor has spread from its original location.
- If the cancer is confined to one location and has not spread, the most common goals for treatment are surgery and cure. This is often the case with skin cancers, as well as cancers of the lung, breast, and colon.
- If the tumor has spread to local lymph nodes only, sometimes these can also be removed.
- If surgery cannot remove all of the cancer, the options for treatment include radiation, chemotherapy, or both. Some cancers require a combination of surgery, radiation, and chemotherapy.
Although treatment for cancer can be difficult, there are many ways to keep up your strength.
If you have radiation treatment, know that:
- Radiation treatment is painless.
- Treatment is usually scheduled every weekday.
- You should allow 30 minutes for each treatment session, although the treatment itself usually takes only a few minutes.
- You should get plenty of rest and eat a well-balanced diet during the course of your radiation therapy.
- Skin in the treated area may become sensitive and easily irritated.
- Side effects of radiation treatment are usually temporary. They vary depending on the area of the body that is being treated.
If you are going through chemotherapy, you should eat right. Chemotherapy causes your immune system to weaken, so you should avoid people with colds or the flu. You should also get plenty of rest, and don't feel as though you have to accomplish tasks all at once.
It will help you to talk with family, friends, or a support group about your feelings. Work with your health care providers throughout your treatment. Helping yourself can make you feel more in control.
Cancer and Mesothelioma 2
The most common form of cancer caused by asbestos is mesothelioma, a rare cancer that is very rarely cured. The only proven cause of mesothelioma is exposure to asbestos.
An estimated 20 to 30 percent of people diagnosed with mesothelioma have no knowledge of prior exposure to asbestos. But the prior popularity of asbestos as a building material may shed some light on a person's ability to identify the source of their exposure to asbestos.
Mesothelioma typically attacks the thin membranous lining of the lungs, abdomen, or heart, known as the mesothelium. It is estimated that 2,000 to 3,000 new cases of mesothelioma are reported each year. The symptoms of mesothelioma typically arise 20 to 50 years after exposure, which makes it difficult to diagnose the countless cases lying dormant across the country. For more information about mesothelioma
An estimated 20 to 30 percent of people diagnosed with mesothelioma have no knowledge of prior exposure to asbestos. But the prior popularity of asbestos as a building material may shed some light on a person's ability to identify the source of their exposure to asbestos.
Mesothelioma typically attacks the thin membranous lining of the lungs, abdomen, or heart, known as the mesothelium. It is estimated that 2,000 to 3,000 new cases of mesothelioma are reported each year. The symptoms of mesothelioma typically arise 20 to 50 years after exposure, which makes it difficult to diagnose the countless cases lying dormant across the country. For more information about mesothelioma
Cancer - The Silent Killer
ancer is the uncontrolled growth of abnormal cells in the body. Cancerous cells are also called malignant cells.
Treating cancer can be very complicated, and it is difficult for even the most educated patients to be sure they have the best care.
Treating cancer can be very complicated, and it is difficult for even the most educated patients to be sure they have the best care.
People who died from mesothelioma
Mesothelioma, though rare, has had a number of patients. Hamilton Jordan, Chief of Staff for President Jimmy Carter and life long cancer activist, died in 2008. Australian anti-racism activist Bob Bellear died in 2005. British science fiction writer Michael G. Coney, responsible for nearly 100 works also died in 2005. American film and television actor Paul Gleason, perhaps best known for his portrayal of Principal Richard Vernon in the 1985 film The Breakfast Club, died in 2006. Mickie Most, an English record producer, died of mesothelioma in 2003. Paul Rudolph, an American architect known for his cubist building designs, died in 1997.
Bernie Banton was an Australian workers' rights activist, who fought a long battle for compensation from James Hardie after he contracted mesothelioma after working for that company. He claimed James Hardie knew of the dangers of asbestos before he began work with the substance making insulation for power stations. Mesothelioma eventually took his life along with his brothers and hundreds of James Hardie workers. James Hardie made an undisclosed settlement with Banton only when his mesothelioma had reached its final stages and he was expected to have no more than 48hrs to live. Australian Prime Minister-elect Kevin Rudd mentioned Banton's extended struggle in his acceptance speech after winning the 2007 Australian Federal Election.
Steve McQueen was diagnosed with peritoneal mesothelioma on December 22, 1979. He was not offered surgery or chemotherapy because doctors felt the cancer was too advanced. McQueen sought alternative treatments from clinics in Mexico. He died of a heart attack on November 7, 1980, in Juárez, Mexico, following cancer surgery. He may have been exposed to asbestos while serving with the U.S. Marines as a young adult—asbestos was then commonly used to insulate ships' piping—or from its use as an insulating material in car racing suits.[14] (It is also reported that he worked in a shipyard during World War II, where he might have been exposed to asbestos
Bernie Banton was an Australian workers' rights activist, who fought a long battle for compensation from James Hardie after he contracted mesothelioma after working for that company. He claimed James Hardie knew of the dangers of asbestos before he began work with the substance making insulation for power stations. Mesothelioma eventually took his life along with his brothers and hundreds of James Hardie workers. James Hardie made an undisclosed settlement with Banton only when his mesothelioma had reached its final stages and he was expected to have no more than 48hrs to live. Australian Prime Minister-elect Kevin Rudd mentioned Banton's extended struggle in his acceptance speech after winning the 2007 Australian Federal Election.
Steve McQueen was diagnosed with peritoneal mesothelioma on December 22, 1979. He was not offered surgery or chemotherapy because doctors felt the cancer was too advanced. McQueen sought alternative treatments from clinics in Mexico. He died of a heart attack on November 7, 1980, in Juárez, Mexico, following cancer surgery. He may have been exposed to asbestos while serving with the U.S. Marines as a young adult—asbestos was then commonly used to insulate ships' piping—or from its use as an insulating material in car racing suits.[14] (It is also reported that he worked in a shipyard during World War II, where he might have been exposed to asbestos
Mesothelioma Prevention tips
The criticism expressed by the estimates Tomatis et al. did not take into account all the pilot projects and all investigations by human pleura that since the Seventies for unanimously declared that asbestos is mesothelioma caused by fibres ultrafine category. These fibres are so fine that is not visible under a microscope light is mainly ultrashort, but will also include, in varying percentages, which is> 5 microm time. The conclusions of Tomatis et al, which attach mesothelioma in all its fibre lengths and diameters, has not been confirmed in the literature. Today, mesothelioma, prevention must consist of identifying and reducing airborne ultrafine fibres, especially in urban environments. The techniques to do now exist and can be implemented. The ultrafine around asbestos, forgotten for decades, should be the main target for prevention programmes and must be controlled to a large extent in work and daily life.
home Prevention Mesothelioma
The first step to be taken to prevent mesothelioma is avoiding exposure to toxic this mineral. Through the asbestos is no longer used in the overwhelming majority of products, this dangerous substance is not banned in the United States and products containing asbestos, even today, such as automobiles and clutch linings break. Since asbestos has been used in many industries for decades, some of the older products in homes may contain asbestos, including:
If these elements are intact, which usually have little to no health risks. However, if damaged or "friable," should be removed from the home immediately. Expulsion must be licensed by a reduction company, as this is the best way to protect you and your family from exposure to asbestos.
home Prevention Mesothelioma
The first step to be taken to prevent mesothelioma is avoiding exposure to toxic this mineral. Through the asbestos is no longer used in the overwhelming majority of products, this dangerous substance is not banned in the United States and products containing asbestos, even today, such as automobiles and clutch linings break. Since asbestos has been used in many industries for decades, some of the older products in homes may contain asbestos, including:
If these elements are intact, which usually have little to no health risks. However, if damaged or "friable," should be removed from the home immediately. Expulsion must be licensed by a reduction company, as this is the best way to protect you and your family from exposure to asbestos.
mesothelioma definition
Definition of Mesothelioma. Mesothelioma: A malignant tumor of the mesothelium. The mesothelium is the thin lining on the surface of the body cavities
mesothelioma definition
Mesothelioma is nothing but a cancer of mesothelium. Mesothelium is the covering structure of most of the internal organs of the body
mesothelioma definition
Mesothelioma is nothing but a cancer of mesothelium. Mesothelium is the covering structure of most of the internal organs of the body
Types of Mesothelioma
Mesothelioma can attack the pleural lining around the lungs. It can also attack the peritoneum, a tissue that surrounds the GI tract. Mesothelioma can attack the stomach lining, other internal organs, or even the pericardium (the tissue sac covering the heart). Thus, mesothelioma can be generally classified into the following types:
Pleural — 75%
Peritoneal — 10%
Pericardial — 5%
Mesothelioma can also be classified by the cancer type rather than the location of the cancer:
Epithelioid — most common.
Sarcomatoid — most severe.
Pleural — 75%
Peritoneal — 10%
Pericardial — 5%
Mesothelioma can also be classified by the cancer type rather than the location of the cancer:
Epithelioid — most common.
Sarcomatoid — most severe.
Cancer and Mesothelioma
The most common form of cancer caused by asbestos is mesothelioma, a rare cancer that is very rarely cured. The only proven cause of mesothelioma is exposure to asbestos.
An estimated 20 to 30 percent of people diagnosed with mesothelioma have no knowledge of prior exposure to asbestos. But the prior popularity of asbestos as a building material may shed some light on a person's ability to identify the source of their exposure to asbestos.
Mesothelioma typically attacks the thin membranous lining of the lungs, abdomen, or heart, known as the mesothelium. It is estimated that 2,000 to 3,000 new cases of mesothelioma are reported each year. The symptoms of mesothelioma typically arise 20 to 50 years after exposure, which makes it difficult to diagnose the countless cases lying dormant across the country. For more information about mesothelioma
An estimated 20 to 30 percent of people diagnosed with mesothelioma have no knowledge of prior exposure to asbestos. But the prior popularity of asbestos as a building material may shed some light on a person's ability to identify the source of their exposure to asbestos.
Mesothelioma typically attacks the thin membranous lining of the lungs, abdomen, or heart, known as the mesothelium. It is estimated that 2,000 to 3,000 new cases of mesothelioma are reported each year. The symptoms of mesothelioma typically arise 20 to 50 years after exposure, which makes it difficult to diagnose the countless cases lying dormant across the country. For more information about mesothelioma
Cancer Stages
The stage of a cancer is a descriptor (usually numbers I to IV) of how much the cancer has spread. The stage often takes into account the size of a tumor, how deep it has penetrated, whether it has invaded adjacent organs, how many lymph nodes it has metastasized to (if any), and whether it has spread to distant organs. Staging of cancer is important because the stage at diagnosis is the most powerful predictor of survival, and treatments are often changed based on the stage.
Overall Stage Grouping is also referred to as Roman Numeral Staging. This system uses numerals I, II, III, and IV (plus the 0) to describe the progression of cancer.
Stage 0 carcinoma in situ.
Stage I cancers are localized to one part of the body.
Stage II cancers are locally advanced, as are stage III
Stage III cancers. Whether a cancer is designated as Stage II or Stage III can depend on the specific type of cancer; for example, in Hodgkin's Disease, Stage II indicates affected lymph nodes on only one side of the diaphragm, whereas Stage III indicates affected lymph nodes above and below the diaphragm. The specific criteria for Stages II and III therefore differ according to diagnosis.
Stage IV cancers have often metastasized, or spread to other organs or throughout the body.
Within the TNM system, a cancer may also be designated as recurrent, meaning that it has appeared again after being in remission or after all visible tumor has been eliminated. Recurrence can either be local, meaning that it appears in the same location as the original, or distant, meaning that it appears in a different part of the body.
Overall Stage Grouping is also referred to as Roman Numeral Staging. This system uses numerals I, II, III, and IV (plus the 0) to describe the progression of cancer.
Stage 0 carcinoma in situ.
Stage I cancers are localized to one part of the body.
Stage II cancers are locally advanced, as are stage III
Stage III cancers. Whether a cancer is designated as Stage II or Stage III can depend on the specific type of cancer; for example, in Hodgkin's Disease, Stage II indicates affected lymph nodes on only one side of the diaphragm, whereas Stage III indicates affected lymph nodes above and below the diaphragm. The specific criteria for Stages II and III therefore differ according to diagnosis.
Stage IV cancers have often metastasized, or spread to other organs or throughout the body.
Within the TNM system, a cancer may also be designated as recurrent, meaning that it has appeared again after being in remission or after all visible tumor has been eliminated. Recurrence can either be local, meaning that it appears in the same location as the original, or distant, meaning that it appears in a different part of the body.
Mesothelioma Lung Cancer
Mesothelioma and lung cancer are both serious illnesses, but they are not the same. Mesothelioma – sometimes called “asbestos lung cancer” – is really not a form of lung cancer because it does not develop in the tissue of the lungs. Instead, it is a cancer of the lining that surrounds the lung (the “pleura”).
Mesothelioma is caused almost exclusively by asbestos exposure. It is considered a “signature disease” for asbestos exposure, which means that, if you have mesothelioma, it can be assumed that you had exposure to asbestos at some point in your life. Smoking does not cause mesothelioma.
Lung cancer can be caused by asbestos exposure; it can also be caused by smoking. In fact, someone who smokes and was exposed to asbestos has a much higher risk of getting lung cancer. See Asbestos and Smoking.
Mesothelioma is caused almost exclusively by asbestos exposure. It is considered a “signature disease” for asbestos exposure, which means that, if you have mesothelioma, it can be assumed that you had exposure to asbestos at some point in your life. Smoking does not cause mesothelioma.
Lung cancer can be caused by asbestos exposure; it can also be caused by smoking. In fact, someone who smokes and was exposed to asbestos has a much higher risk of getting lung cancer. See Asbestos and Smoking.
Saturday, April 18, 2009
Cloning: There’ll Never Be Another You
Depending upon your point of view, cloning organisms may sound like a
nightmare or a dream come true. Whatever your opinion, cloning is most definitely
not science fiction; decisions about experimental cloning are being
made right now, every day. This chapter covers cloning: what it is, how it’s
done, and what its impact is from a biological point of view. Cloning (like just
about everything else in science) isn’t as simple as the media makes it sound.
In this chapter, you get to know the problems inherent in clones along with
the arguments for and against cloning (not just of humans — of animals and
plants, too). Get ready for an interesting story. Remember, it ain’t fiction!
nightmare or a dream come true. Whatever your opinion, cloning is most definitely
not science fiction; decisions about experimental cloning are being
made right now, every day. This chapter covers cloning: what it is, how it’s
done, and what its impact is from a biological point of view. Cloning (like just
about everything else in science) isn’t as simple as the media makes it sound.
In this chapter, you get to know the problems inherent in clones along with
the arguments for and against cloning (not just of humans — of animals and
plants, too). Get ready for an interesting story. Remember, it ain’t fiction!
cloning
The other use of the word cloning means to make a copy of an entire organism
as a reproductive strategy. When referring to a whole creature as opposed to
DNA, a clone is an organism that’s created via asexual reproduction, meaning
offspring are produced without the parent having sex first. Cloning occurs naturally
all the time in bacteria, plants, insects, fish, and lizards. For example,
one type of asexual reproduction is parthenogenesis, which occurs when a
female makes eggs that develop into offspring without being fertilized by a
male (for some of you female readers, I’m sure this sounds very appealing). So
if reproduction by cloning is a natural, normal biological process, what’s the
big deal with cloning organisms using technology?
as a reproductive strategy. When referring to a whole creature as opposed to
DNA, a clone is an organism that’s created via asexual reproduction, meaning
offspring are produced without the parent having sex first. Cloning occurs naturally
all the time in bacteria, plants, insects, fish, and lizards. For example,
one type of asexual reproduction is parthenogenesis, which occurs when a
female makes eggs that develop into offspring without being fertilized by a
male (for some of you female readers, I’m sure this sounds very appealing). So
if reproduction by cloning is a natural, normal biological process, what’s the
big deal with cloning organisms using technology?
Attack of the Clones
A clone is simply an identical copy. The word is used as both a verb, as in “to
clone” (make one) and a noun, as in “a clone” (have one or be one).
Genetically, the word clone can have two meanings. When geneticists talk
about cloning, they’re most often talking about copying some part of the DNA
(usually a gene). Geneticists clone DNA in the lab every day — the technology
is simple, routine, and unremarkable.
clone” (make one) and a noun, as in “a clone” (have one or be one).
Genetically, the word clone can have two meanings. When geneticists talk
about cloning, they’re most often talking about copying some part of the DNA
(usually a gene). Geneticists clone DNA in the lab every day — the technology
is simple, routine, and unremarkable.
Cloning before Dolly: Working with sex cells
Experimental cloning started in the 1950s. In 1952, researchers transplanted
the nucleus from a frog embryo into a frog egg. This and subsequent experiments
were designed not to clone frogs but to discover the basis of totipotents.
the nucleus from a frog embryo into a frog egg. This and subsequent experiments
were designed not to clone frogs but to discover the basis of totipotents.
cells rearrange
After a few more divisions, the cells rearrange into a three-layered ball called
a gastrula. The innermost layer of the gastrula is endoderm (literally “inner
skin”), the middle is mesoderm (“middle skin”), and the outermost is ectoderm
(“outer skin”). Each layer is composed of a batch of cells, so from the
gastrula stage onward, what cells turn into depends on which layer they start
out in. In other words, the cells are no longer totipotent; they have specific
functions.
a gastrula. The innermost layer of the gastrula is endoderm (literally “inner
skin”), the middle is mesoderm (“middle skin”), and the outermost is ectoderm
(“outer skin”). Each layer is composed of a batch of cells, so from the
gastrula stage onward, what cells turn into depends on which layer they start
out in. In other words, the cells are no longer totipotent; they have specific
functions.
therapeutic cloning
The promise of therapeutic cloning is that someday doctors will be able to
harvest your cells, use your DNA to make totipotent cells, and then use those
cells to cure your life-threatening disease or restore your damaged spinal
cord to full working order. Creating totipotent cells from nullipotent cells to
treat injury or disease is difficult and triggers significant ethical debates (see
“Weighing Both Sides of the Cloning Debate” later in this chapter). Realizing
the potential of therapeutic cloning may be a very long way off. Meanwhile,
reproductive cloning — the process of creating offspring asexually — is
already causing quite a stir. For a taste of some of the excitement, see the
sidebar “Aclone in the universe?”.
harvest your cells, use your DNA to make totipotent cells, and then use those
cells to cure your life-threatening disease or restore your damaged spinal
cord to full working order. Creating totipotent cells from nullipotent cells to
treat injury or disease is difficult and triggers significant ethical debates (see
“Weighing Both Sides of the Cloning Debate” later in this chapter). Realizing
the potential of therapeutic cloning may be a very long way off. Meanwhile,
reproductive cloning — the process of creating offspring asexually — is
already causing quite a stir. For a taste of some of the excitement, see the
sidebar “Aclone in the universe?”.
Artificial twinning
Artificial twinning is relatively simple and was first done successfully (in
sheep) in 1979. A single fertilized egg was used, meaning that the resulting
offspring was the result of sexual reproduction. Zygotes from normally fertilized
(sexually produced) eggs were harvested from ewes (female sheep). The
zygote was allowed to divide up to the 16-cell stage (see the “Cloning before
Dolly: Working with sex cells” section earlier in the chapter). The 16 cells
were then divided into two groups. The separate groups of cells went right on
dividing, and after they were implanted into the reproductive tract of the
ewe, they resulted in twins. The twins were genetically identical to each other
because they were produced from the same fertilized egg.
sheep) in 1979. A single fertilized egg was used, meaning that the resulting
offspring was the result of sexual reproduction. Zygotes from normally fertilized
(sexually produced) eggs were harvested from ewes (female sheep). The
zygote was allowed to divide up to the 16-cell stage (see the “Cloning before
Dolly: Working with sex cells” section earlier in the chapter). The 16 cells
were then divided into two groups. The separate groups of cells went right on
dividing, and after they were implanted into the reproductive tract of the
ewe, they resulted in twins. The twins were genetically identical to each other
because they were produced from the same fertilized egg.
Friday, April 10, 2009
Skin Cancer
Skin Cancer
Skin cancer is a disease in which cancer cells grow in the tissues of the skin. There are two major groups: nonmelanoma and melanoma. Nonmelanoma skin cancers are by far the most common types of cancer, with more than 1 million new cases diagnosed annually, and most are highly curable. Melanoma is much less common, but more serious. Melanoma is highly curable in its early stages, but may spread to other parts of the body.
At Ohio State's Comprehensive Cancer Center – James Cancer Hospital and Solove Research Institute, we have skin cancer experts who have dedicated their lives to providing the best skin cancer research and treatment. With research and treatment areas under one roof, we are better able to apply research advances to patient care. Recent research advancements include:
A laboratory study led by Anne VanBuskirk, PhD, OSUCCC Immunology Program, to find immunological approaches to help organ transplant patients fight skin cancer, a disease to which they are highly susceptible.
Clinical trials directed by William Carson, MD, a surgical oncologist at The James and leader of the OSUCCC Immunology Program, and Michael Walker, MD, a surgical oncologist specializing in melanoma at The James, based on immunology and the promise of a “vaccine” to help slow or stop the growth of malignant melanoma.
A study examining the use of a newly developed, molecularly targeted drug designed to inhibit key cancer growth factors. Interim results suggest the drug may be helpful in controlling malignant melanoma, which typically responds poorly to traditional treatments with chemotherapy or radiation.
Skin cancer is a disease in which cancer cells grow in the tissues of the skin. There are two major groups: nonmelanoma and melanoma. Nonmelanoma skin cancers are by far the most common types of cancer, with more than 1 million new cases diagnosed annually, and most are highly curable. Melanoma is much less common, but more serious. Melanoma is highly curable in its early stages, but may spread to other parts of the body.
At Ohio State's Comprehensive Cancer Center – James Cancer Hospital and Solove Research Institute, we have skin cancer experts who have dedicated their lives to providing the best skin cancer research and treatment. With research and treatment areas under one roof, we are better able to apply research advances to patient care. Recent research advancements include:
A laboratory study led by Anne VanBuskirk, PhD, OSUCCC Immunology Program, to find immunological approaches to help organ transplant patients fight skin cancer, a disease to which they are highly susceptible.
Clinical trials directed by William Carson, MD, a surgical oncologist at The James and leader of the OSUCCC Immunology Program, and Michael Walker, MD, a surgical oncologist specializing in melanoma at The James, based on immunology and the promise of a “vaccine” to help slow or stop the growth of malignant melanoma.
A study examining the use of a newly developed, molecularly targeted drug designed to inhibit key cancer growth factors. Interim results suggest the drug may be helpful in controlling malignant melanoma, which typically responds poorly to traditional treatments with chemotherapy or radiation.
Prostate Cancer
The prostate, part of the male reproductive system, is a gland located under the bladder and in front of the rectum. Prostate cancer usually begins in the gland cells and grows slowly, so many men have prostate cancer but are unaware of it. Sometimes, however, prostate cancer will grow and spread quickly. Prostate cancer is highly curable when detected and treated early.
Unfortunately, many men with prostate cancer become confused regarding the complex array of options that are available for prevention and treatment. The Prostate Cancer and Genitourinary Oncology Program at The James can help men and their families choose among the array of prostate cancer treatment options.
In addition, The James is a cutting-edge research facility where discovery is translated into more effective prevention and diagnostic strategies as well as more effective and safer treatments. Among recent research advances:
The James was one of many sites in a national study involving 18,000 men that demonstrated the ability of a hormonal agent, finasteride, to reduce the risk of prostate cancer by 25 percent. More than 250 men in Ohio and Kentucky participated through the Ohio State clinics directed by Steven K. Clinton, MD, PhD, and Robert Bahnson, MD. The study was the first in history to demonstrate that an intervention could protect men from developing prostate cancer.
The James is participating in the largest prostate cancer prevention trial to date, called SELECT (Selenium and Vitamin E Cancer Prevention Trial). The Ohio State effort, directed by J. Paul Monk, MD, and Drs. Clinton and Bahnson, will determine whether dietary supplements of vitamin E and selenium can prevent prostate cancer. The 12-year study is expected to involve more than 400 trial sites, with approximately 32,000 healthy men over the age of 55 (over 50 for African-Americans) participating.
Dr. Clinton and colleagues at the OSUCCC – James are seeking to prove whether consumption of tomato-based products and soy can reduce the risk of prostate cancer, as epidemiologic studies have suggested. These investigators are bringing dietary and nutritional studies into the clinic, where men with prostate cancer are able to participate in these important and exciting clinical trials.
Unfortunately, many men with prostate cancer become confused regarding the complex array of options that are available for prevention and treatment. The Prostate Cancer and Genitourinary Oncology Program at The James can help men and their families choose among the array of prostate cancer treatment options.
In addition, The James is a cutting-edge research facility where discovery is translated into more effective prevention and diagnostic strategies as well as more effective and safer treatments. Among recent research advances:
The James was one of many sites in a national study involving 18,000 men that demonstrated the ability of a hormonal agent, finasteride, to reduce the risk of prostate cancer by 25 percent. More than 250 men in Ohio and Kentucky participated through the Ohio State clinics directed by Steven K. Clinton, MD, PhD, and Robert Bahnson, MD. The study was the first in history to demonstrate that an intervention could protect men from developing prostate cancer.
The James is participating in the largest prostate cancer prevention trial to date, called SELECT (Selenium and Vitamin E Cancer Prevention Trial). The Ohio State effort, directed by J. Paul Monk, MD, and Drs. Clinton and Bahnson, will determine whether dietary supplements of vitamin E and selenium can prevent prostate cancer. The 12-year study is expected to involve more than 400 trial sites, with approximately 32,000 healthy men over the age of 55 (over 50 for African-Americans) participating.
Dr. Clinton and colleagues at the OSUCCC – James are seeking to prove whether consumption of tomato-based products and soy can reduce the risk of prostate cancer, as epidemiologic studies have suggested. These investigators are bringing dietary and nutritional studies into the clinic, where men with prostate cancer are able to participate in these important and exciting clinical trials.
Lung Cancer
Cancer of the lung, like all cancers, results from an abnormality in the body's basic unit of life, the cell. Normally, the body maintains a system of checks and balances on cell growth so that cells divide to produce new cells only when needed. Disruption of this system of checks and balances on cell growth results in an uncontrolled division and proliferation of cells that eventually forms a mass known as a tumor.
Tumors can be benign or malignant; when we speak of "cancer," we refer to those tumors that are considered malignant. Benign tumors can usually be removed and do not spread to other parts of the body. Malignant tumors, on the other hand, grow aggressively and invade other tissues of the body, allowing entry of tumor cells into the bloodstream or lymphatic system and then to other sites in the body. This process of spread is termed metastasis; the areas of tumor growth at these distant sites are called metastases. Since lung cancer tends to spread or metastasize very early in its course, it is a very life-threatening cancer and one of the most difficult cancers to treat. While lung cancer can spread to any organ in the body, certain organs -- particularly the adrenal glands, liver, brain, and bone -- are the most common sites for lung-cancer metastasis.
The lung is also a very common site for metastasis from tumors in other parts of the body. Tumor metastases are made up of the same type of cells as the original, or primary, tumor. For example, if prostate cancer spreads via the bloodstream to the lungs, it is metastatic prostate cancer in the lung and is not lung cancer.
The principal function of the lungs is the exchange of gases between the air we breathe and the blood. Through the lung, carbon dioxide is removed from the bloodstream and oxygen from inspired air enters the bloodstream. The right lung has three lobes, while the left lung is divided into two lobes and a small structure called the lingula that is the equivalent of the middle lobe. The major airways entering the lungs are the bronchi, which arise from the trachea. The bronchi branch into progressively smaller airways called bronchioles that end in tiny sacs known as alveoli where gas exchange occurs. The lungs and chest wall are covered with a thin layer of tissue called the pleura.
Lung cancers can arise in any part of the lung, but 90%-95% of cancers of the lung are thought to arise from the epithelial, or lining cells of the larger and smaller airways (bronchi and bronchioles); for this reason, lung cancers are sometimes called bronchogenic carcinomas or bronchogenic cancers. Cancers can also arise from the pleura (the thin layer of tissue that surrounds the lungs), called mesotheliomas, or rarely from supporting tissues within the lungs, for example, blood vessels.
Pancreatic Cancer
The pancreas is an organ in the upper abdomen located beneath the stomach and adjacent to the first portion of the small intestine, called the duodenum. The pancreas is composed of glands that are responsible for a wide variety of tasks. The glandular functions of the pancreas can be divided into the following 2 categories:
Exocrine: The exocrine glands secrete enzymes into ducts that eventually empty into the duodenum. These enzymes then help in the digestion of food as it moves through the intestines.
Endocrine: The endocrine glands secrete hormones, including insulin, into the bloodstream. Insulin is carried by the blood throughout the rest of the body to assist in the process of using sugar as an energy source. Insulin also controls the levels of sugar in the blood.
The pancreas can be divided into the following 4 anatomical sections:
Head - The rightmost portion that lies adjacent to the duodenum
Uncinate process - An extension of the head of the pancreas
Body - The middle portion of the pancreas
Tail - The leftmost portion of the pancreas that lies adjacent to the spleen
Intraductal papillary mucinous neoplasia (IPMN) is a type of pancreatic cancer that is beginning to be recognized more frequently. This pancreatic cancer has a better prognosis than other types of pancreatic cancer. Intraductal papillary mucinous neoplasia is usually diagnosed endoscopically (see Exams and Tests).
The most common type of pancreatic cancer arises from the exocrine glands and is called adenocarcinoma of the pancreas. The endocrine glands of the pancreas can give rise to a completely different type of cancer, referred to as pancreatic neuroendocrine carcinoma or islet cell tumor. This article only discusses issues related to the more common type of pancreatic adenocarcinoma.Pancreatic adenocarcinoma is among the most aggressive of all cancers. By the time that pancreatic cancer is diagnosed, most people already have disease that has spread to distant sites in the body. Pancreatic cancer is also relatively resistant to medical treatment, and the only potentially curative treatment is surgery. In 2004, approximately 31,800 people in the United States were diagnosed with pancreatic cancer, and approximately 31,200 people died of this disease. These numbers reflect the challenge in treating pancreatic cancer and the relative lack of curative options.
Exocrine: The exocrine glands secrete enzymes into ducts that eventually empty into the duodenum. These enzymes then help in the digestion of food as it moves through the intestines.
Endocrine: The endocrine glands secrete hormones, including insulin, into the bloodstream. Insulin is carried by the blood throughout the rest of the body to assist in the process of using sugar as an energy source. Insulin also controls the levels of sugar in the blood.
The pancreas can be divided into the following 4 anatomical sections:
Head - The rightmost portion that lies adjacent to the duodenum
Uncinate process - An extension of the head of the pancreas
Body - The middle portion of the pancreas
Tail - The leftmost portion of the pancreas that lies adjacent to the spleen
Intraductal papillary mucinous neoplasia (IPMN) is a type of pancreatic cancer that is beginning to be recognized more frequently. This pancreatic cancer has a better prognosis than other types of pancreatic cancer. Intraductal papillary mucinous neoplasia is usually diagnosed endoscopically (see Exams and Tests).
The most common type of pancreatic cancer arises from the exocrine glands and is called adenocarcinoma of the pancreas. The endocrine glands of the pancreas can give rise to a completely different type of cancer, referred to as pancreatic neuroendocrine carcinoma or islet cell tumor. This article only discusses issues related to the more common type of pancreatic adenocarcinoma.Pancreatic adenocarcinoma is among the most aggressive of all cancers. By the time that pancreatic cancer is diagnosed, most people already have disease that has spread to distant sites in the body. Pancreatic cancer is also relatively resistant to medical treatment, and the only potentially curative treatment is surgery. In 2004, approximately 31,800 people in the United States were diagnosed with pancreatic cancer, and approximately 31,200 people died of this disease. These numbers reflect the challenge in treating pancreatic cancer and the relative lack of curative options.
Thursday, April 2, 2009
Brain Awareness Week 2009
Earlier this week members of the Galway Neuroscience Group reported their experience of holding a public event as part of global 'Brain Awareness Week'. Supported financially by the Dana Foundation, BAW is a multi-national effort aimed at making as many people as possible interested in their own brains. Activities include visits to schools by neuroscientists, or information dissemination by various neurological organisations like Neurology Alliance Ireland, Dystonia Ireland, the Dublin Brain Bank and MS Ireland. Galway neuroscientists chose 'The beauty of neuroscience' as their theme, displaying beautiful prints of cells and tissue gnerated during the course of their own research activities. Poster stands and a microscope with sample tissue and cells for viewing, were set up at the Eyre Square Shopping centre on March 19th and 20th. A separate table dedicated to interactive questionairs and brain colouring booklets for children was also a feature. For more information about the activities of the Galway Neuroscience Group, go to http://www.ncbes.ie/research/NeuroscienceOverview.htm
Biomedical technology and Silicon Valley
On Thursday, Jan 31st, I attended a seminar on Biomedical Technology hosted by Silicon Valley Technical Institute. The instructor was Dr. Sudhi Gautam, an ex-ENT surgeon with a PhD in Engineering from the Indian Institute of Technology. For a layman in biomedical technology like me, it was an eye-opener. Overall, a most excellent introduction to biomedical technology.
To begin with, I did not know the difference between biotechnology and biomedical engineering (not to be confused with bioengineering). It turns out that biotechnology is best defined as the technology concerned with manipulation of living cells and is most related to biology. Biomedical engineering is at the convergence of technology, medicine and biology and is focused on developing medical devices and systems. Bioengineering is concerned with modification animal and plant cells by manipulating their genetic and cellular properties. So similar sounding names, with very different meanings. Furthermore, the regulatory approval process in the United States is dramatically different for biotechnology compared to biomedical devices.
Biomedical devices are classified based on their level of risk application and impact, and in the low risk devices can be approved anywhere from 90 days to 3 years. Biotechnology applications, especially where they have therapeutic applications go through the same cycle of approvals and clinical trial as pharmaceutical drugs and can generally take anywhere from 4 to 7 years or more to get approved. Some of the higher risk biomedical devices like pacemakers and robotic surgery machines like those from Intuitive Surgical can also take as long to be approved by the US regulatory bodies.
Where it gets very interesting is in that biomedical engineering, because of its intersection between engineering and medicine, has a great deal of relevance to Silicon Valley. Even with all the advances in medicine today, the gap between medicine and technology outside of medicine is huge. This makes the health care system very inefficient. This triggers the opportunity, which is so characteristic of others, which Silicon Valley exploits best, with its mix of capital, technology and entrepreneurship. California has close to 2600 biomedical companies, with over 700 in the Bay Area alone. Silicon Valley appears to be the biggest hub for biomedical technology, followed by Orange County, Minneapolis and the Northeastern US. Many of the Bay Area companies are spinoffs from Stanford, UC Berkeley and UCSF. The estimate is that 50% of the world’s biotech and biomedical companies are in the US and a very high percentage of them are in California. US biomedical devices are valued worldwide due to the rigorous approval process and quality requirements they are subjected to. These devices require a significant amount of engineering design and and in many cases have significant semiconductor content. Where the devices are endorsed by Medicare or the insurance companies for use by their patients, the volume can also be considerable at pretty good margins.
The latest biomedical device company in the news is Intuitive Surgical (mentioned earlier) of Sunnyvale, CA. They make the robotic surgery machines, called the da Vinci surgical system. These are approved only for three or four types of surgical procedures in the US (they are seeking approval for more types of procedures), but are still in hot demand in India and other countries. The latest rumor is that their machines have been approved for hysterectomies by the US regulatory bodies. This may account for the fact that their stock (ISRG) surged over 17% on Friday, February 2nd alone and is up close to 50% in less than a month.
So, following semiconductors, computers, the Internet, the iPod and iPhone, we have a lineup of alternative energy, biotech and biomedical products to supply the world. These are exciting times indeed for Silicon Valley.
To begin with, I did not know the difference between biotechnology and biomedical engineering (not to be confused with bioengineering). It turns out that biotechnology is best defined as the technology concerned with manipulation of living cells and is most related to biology. Biomedical engineering is at the convergence of technology, medicine and biology and is focused on developing medical devices and systems. Bioengineering is concerned with modification animal and plant cells by manipulating their genetic and cellular properties. So similar sounding names, with very different meanings. Furthermore, the regulatory approval process in the United States is dramatically different for biotechnology compared to biomedical devices.
Biomedical devices are classified based on their level of risk application and impact, and in the low risk devices can be approved anywhere from 90 days to 3 years. Biotechnology applications, especially where they have therapeutic applications go through the same cycle of approvals and clinical trial as pharmaceutical drugs and can generally take anywhere from 4 to 7 years or more to get approved. Some of the higher risk biomedical devices like pacemakers and robotic surgery machines like those from Intuitive Surgical can also take as long to be approved by the US regulatory bodies.
Where it gets very interesting is in that biomedical engineering, because of its intersection between engineering and medicine, has a great deal of relevance to Silicon Valley. Even with all the advances in medicine today, the gap between medicine and technology outside of medicine is huge. This makes the health care system very inefficient. This triggers the opportunity, which is so characteristic of others, which Silicon Valley exploits best, with its mix of capital, technology and entrepreneurship. California has close to 2600 biomedical companies, with over 700 in the Bay Area alone. Silicon Valley appears to be the biggest hub for biomedical technology, followed by Orange County, Minneapolis and the Northeastern US. Many of the Bay Area companies are spinoffs from Stanford, UC Berkeley and UCSF. The estimate is that 50% of the world’s biotech and biomedical companies are in the US and a very high percentage of them are in California. US biomedical devices are valued worldwide due to the rigorous approval process and quality requirements they are subjected to. These devices require a significant amount of engineering design and and in many cases have significant semiconductor content. Where the devices are endorsed by Medicare or the insurance companies for use by their patients, the volume can also be considerable at pretty good margins.
The latest biomedical device company in the news is Intuitive Surgical (mentioned earlier) of Sunnyvale, CA. They make the robotic surgery machines, called the da Vinci surgical system. These are approved only for three or four types of surgical procedures in the US (they are seeking approval for more types of procedures), but are still in hot demand in India and other countries. The latest rumor is that their machines have been approved for hysterectomies by the US regulatory bodies. This may account for the fact that their stock (ISRG) surged over 17% on Friday, February 2nd alone and is up close to 50% in less than a month.
So, following semiconductors, computers, the Internet, the iPod and iPhone, we have a lineup of alternative energy, biotech and biomedical products to supply the world. These are exciting times indeed for Silicon Valley.
Wednesday, April 1, 2009
Cancer symptoms n detection
Abnormal sensations or conditions that persons can notice that are a result of a cancer. It is important to see your doctor for regular checkups and not wait for problems to occur. But you should also know that the following symptoms may be associated with cancer: changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or lump in the breast or any other part of the body, indigestion or difficulty swallowing, obvious change in a wart or mole, or nagging cough or hoarseness. These symptoms are not always a sign of cancer. They can also be caused by less serious conditions. Only a doctor can make a diagnosis. It is important to see a doctor if you have any of these symptoms. Don't wait to feel pain. Early cancer often does not cause pain.
Cancer detection:
Methods used to find cancer in persons who may or may not have symptoms. Symptoms of cancer are abnormal sensations or conditions that persons can notice that are a result of the cancer. It is important to your doctor for regular checkups and not wait for problems to occur. But you should also know that the following symptoms may be associated with cancer: changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or lump in the breast or any other part of the body, indigestion or difficulty swallowing, obvious change in a wart or mole, or nagging cough or hoarseness. These symptoms are not always a sign of cancer. They can also be caused by less serious conditions. Only a doctor can make a diagnosis. It is important to see a doctor if you have any of these symptoms. Don't wait to feel pain. Early cancer often does not cause pain.
Cancer detection:
Methods used to find cancer in persons who may or may not have symptoms. Symptoms of cancer are abnormal sensations or conditions that persons can notice that are a result of the cancer. It is important to your doctor for regular checkups and not wait for problems to occur. But you should also know that the following symptoms may be associated with cancer: changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or lump in the breast or any other part of the body, indigestion or difficulty swallowing, obvious change in a wart or mole, or nagging cough or hoarseness. These symptoms are not always a sign of cancer. They can also be caused by less serious conditions. Only a doctor can make a diagnosis. It is important to see a doctor if you have any of these symptoms. Don't wait to feel pain. Early cancer often does not cause pain.
Cancer registry
A register designed to collect information about the occurrence (incidence) of cancer, the types of cancers that occur and their locations within the body, the extent of cancer at the time of diagnosis (disease stage), and the kinds of treatment that patients receive. In the US, these data are reported to a central statewide registry from various medical facilities, including hospitals, physicians' offices, therapeutic radiation facilities, freestanding surgical centers, and pathology laboratories.
Data collected by state cancer registries enable public health professionals to better understand and address the cancer burden. Registry data are critical for targeting programs focused on risk-related behaviors (eg, tobacco use and exposure to the sun) or on environmental risk factors (eg, radiation and chemical exposures). Such information is also essential for identifying when and where cancer screening efforts should be enhanced and for monitoring the treatment provided to cancer patients. In addition, reliable registry data are fundamental to a variety of research efforts, including those aimed at evaluating the effectiveness of cancer prevention, control, or treatment programs.
State cancer registries in the US and comparable cancer registries in all countries are designed to:
Monitor cancer trends over time.
Determine cancer patterns in various populations.
Guide planning and evaluation of cancer control programs (eg, determine whether prevention, screening, and treatment efforts are making a difference).
Help set priorities for allocating health resources.
Advance clinical, epidemiologic, and health services research.
Provide information for a national database of cancer incidence.
In the US, the Centers for Disease Control and Prevention (CDC) has administered the National Program of Cancer Registries (NPCR) since 1994. This program is currently helping states and U.S. territories to:
Improve their cancer registries.
Meet standards for data completeness, timeliness, and quality.
Use cancer data to support cancer prevention and control programs.
Train registry personnel.
Establish computerized reporting and data-processing systems.
Develop laws and regulations that strengthen registry operations.
Before the NPCR was established, 10 states in the US had no cancer registry and most states with registries lacked the resources and legislative support needed to gather complete data. With fiscal year 2002 funding of approximately $40 million, CDC's NPCR supported central registries and promoted the use of registry data in 45 states, the District of Columbia, and the territories of Puerto Rico, the Republic of Palau, and the Virgin Islands. CDC also developed special research projects such as studies to examine patterns of cancer care in specific populations. CDC's goal is for all states to maintain registries that provide high-quality data on cancer and cancer care.
NPCR complements NCI's Surveillance, Epidemiology, and End Results (SEER) registry program. Together, NPCR and the SEER program collect cancer data for the entire U.S. population. The SEER program gathers in-depth data on cancer cases diagnosed in Connecticut, Hawaii, Iowa, New Mexico, and Utah, as well as in six metropolitan areas and several rural/special population areas. The six metropolitan SEER registries and some of the rural/special population registries submit data to NPCR's state registries. In 2001, SEER began providing additional support to four NPCR-supported state registries (California, Kentucky, Louisiana, and New Jersey).
A cancer registry operated on the state level in the United States. Data collected by state cancer registries enable public health professionals to better understand and address the cancer burden. Registry data are critical for targeting programs focused on risk-related behaviors (eg, tobacco use and exposure to the sun) or on environmental risk factors (eg, radiation and chemical exposures). Such information is also essential for identifying when and where cancer screening efforts should be enhanced and for monitoring the treatment provided to cancer patients. In addition, reliable registry data are fundamental to a variety of research efforts, including those aimed at evaluating the effectiveness of cancer prevention, control, or treatment programs.
State cancer registries in the US and comparable cancer registries in all countries are designed to:
Monitor cancer trends over time.
Determine cancer patterns in various populations.
Guide planning and evaluation of cancer control programs (eg, determine whether prevention, screening, and treatment efforts are making a difference).
Help set priorities for allocating health resources.
Advance clinical, epidemiologic, and health services research.
Provide information for a national database of cancer incidence.
Data collected by state cancer registries enable public health professionals to better understand and address the cancer burden. Registry data are critical for targeting programs focused on risk-related behaviors (eg, tobacco use and exposure to the sun) or on environmental risk factors (eg, radiation and chemical exposures). Such information is also essential for identifying when and where cancer screening efforts should be enhanced and for monitoring the treatment provided to cancer patients. In addition, reliable registry data are fundamental to a variety of research efforts, including those aimed at evaluating the effectiveness of cancer prevention, control, or treatment programs.
State cancer registries in the US and comparable cancer registries in all countries are designed to:
Monitor cancer trends over time.
Determine cancer patterns in various populations.
Guide planning and evaluation of cancer control programs (eg, determine whether prevention, screening, and treatment efforts are making a difference).
Help set priorities for allocating health resources.
Advance clinical, epidemiologic, and health services research.
Provide information for a national database of cancer incidence.
In the US, the Centers for Disease Control and Prevention (CDC) has administered the National Program of Cancer Registries (NPCR) since 1994. This program is currently helping states and U.S. territories to:
Improve their cancer registries.
Meet standards for data completeness, timeliness, and quality.
Use cancer data to support cancer prevention and control programs.
Train registry personnel.
Establish computerized reporting and data-processing systems.
Develop laws and regulations that strengthen registry operations.
Before the NPCR was established, 10 states in the US had no cancer registry and most states with registries lacked the resources and legislative support needed to gather complete data. With fiscal year 2002 funding of approximately $40 million, CDC's NPCR supported central registries and promoted the use of registry data in 45 states, the District of Columbia, and the territories of Puerto Rico, the Republic of Palau, and the Virgin Islands. CDC also developed special research projects such as studies to examine patterns of cancer care in specific populations. CDC's goal is for all states to maintain registries that provide high-quality data on cancer and cancer care.
NPCR complements NCI's Surveillance, Epidemiology, and End Results (SEER) registry program. Together, NPCR and the SEER program collect cancer data for the entire U.S. population. The SEER program gathers in-depth data on cancer cases diagnosed in Connecticut, Hawaii, Iowa, New Mexico, and Utah, as well as in six metropolitan areas and several rural/special population areas. The six metropolitan SEER registries and some of the rural/special population registries submit data to NPCR's state registries. In 2001, SEER began providing additional support to four NPCR-supported state registries (California, Kentucky, Louisiana, and New Jersey).
A cancer registry operated on the state level in the United States. Data collected by state cancer registries enable public health professionals to better understand and address the cancer burden. Registry data are critical for targeting programs focused on risk-related behaviors (eg, tobacco use and exposure to the sun) or on environmental risk factors (eg, radiation and chemical exposures). Such information is also essential for identifying when and where cancer screening efforts should be enhanced and for monitoring the treatment provided to cancer patients. In addition, reliable registry data are fundamental to a variety of research efforts, including those aimed at evaluating the effectiveness of cancer prevention, control, or treatment programs.
State cancer registries in the US and comparable cancer registries in all countries are designed to:
Monitor cancer trends over time.
Determine cancer patterns in various populations.
Guide planning and evaluation of cancer control programs (eg, determine whether prevention, screening, and treatment efforts are making a difference).
Help set priorities for allocating health resources.
Advance clinical, epidemiologic, and health services research.
Provide information for a national database of cancer incidence.
Managing Cancer Pain
The World Health Organization developed a 3-step approach for pain management based on the severity of the pain:
For mild to moderate pain, the doctor may prescribe a Step 1 pain medication such as aspirin, acetaminophen, or a nonsteroidal anti-inflammatory drug (NSAID). Patients should be monitored for side effects, especially those caused by NSAIDs, such as kidney, heart and blood vessel, or stomach and intestinal problems.
When pain lasts or increases, the doctor may change the prescription to a Step 2 or Step 3 pain medication. Most patients with cancer -related pain will need a Step 2 or Step 3 medication. The doctor may skip Step 1 medications if the patient initially has moderate to severe pain.
At each step, the doctor may prescribe additional drugs or treatments (for example, radiation therapy).
The patient should take doses regularly, "by mouth, by the clock" (at scheduled times), to maintain a constant level of the drug in the body; this will help prevent recurrence of pain. If the patient is unable to swallow, the drugs are given by other routes (for example, by infusion or injection).
The doctor may prescribe additional doses of drug that can be taken as needed for pain that occurs between scheduled doses of drug.
The doctor will adjust the pain medication regimen for each patient's individual circumstances and physical condition.
Acetaminophen and NSAIDs
NSAIDs are effective for relief of mild pain. They may be given with opioids for the relief of moderate to severe pain. Acetaminophen also relieves pain, although it does not have the anti-inflammatory effect that aspirin and NSAIDs do. Patients, especially older patients, who are taking acetaminophen or NSAIDs should be closely monitored for side effects. Aspirin should not be given to children to treat pain.
Opioids
Opioids are very effective for the relief of moderate to severe pain. Many patients with cancer pain, however, become tolerant to opioids during long-term therapy. Therefore, increasing doses may be needed to continue to relieve pain. A patient's tolerance of an opioid or physical dependence on it is not the same as addiction (psychological dependence). Mistaken concerns about addiction can result in undertreating pain.
Types of Opioids
There are several types of opioids. Morphine is the most commonly used opioid in cancer pain management. Other commonly used opioids include hydromorphone, oxycodone, methadone, fentanyl, and tramadol. The availability of several different opioids allows the doctor flexibility in prescribing a medication regimen that will meet individual patient needs.
Guidelines for Giving Opioids
Most patients with cancer pain will need to receive pain medication on a fixed schedule to manage the pain and prevent it from getting worse. The doctor will prescribe a dose of the opioid medication that can be taken as needed along with the regular fixed-schedule opioid to control pain that occurs between the scheduled doses. The amount of time between doses depends on which opioid the doctor prescribes. The correct dose is the amount of opioid that controls pain with the fewest side effects. The goal is to achieve a good balance between pain relief and side effects by gradually adjusting the dose. If opioid tolerance does occur, it can be overcome by increasing the dose or changing to another opioid, especially if higher doses are needed.
For mild to moderate pain, the doctor may prescribe a Step 1 pain medication such as aspirin, acetaminophen, or a nonsteroidal anti-inflammatory drug (NSAID). Patients should be monitored for side effects, especially those caused by NSAIDs, such as kidney, heart and blood vessel, or stomach and intestinal problems.
When pain lasts or increases, the doctor may change the prescription to a Step 2 or Step 3 pain medication. Most patients with cancer -related pain will need a Step 2 or Step 3 medication. The doctor may skip Step 1 medications if the patient initially has moderate to severe pain.
At each step, the doctor may prescribe additional drugs or treatments (for example, radiation therapy).
The patient should take doses regularly, "by mouth, by the clock" (at scheduled times), to maintain a constant level of the drug in the body; this will help prevent recurrence of pain. If the patient is unable to swallow, the drugs are given by other routes (for example, by infusion or injection).
The doctor may prescribe additional doses of drug that can be taken as needed for pain that occurs between scheduled doses of drug.
The doctor will adjust the pain medication regimen for each patient's individual circumstances and physical condition.
Acetaminophen and NSAIDs
NSAIDs are effective for relief of mild pain. They may be given with opioids for the relief of moderate to severe pain. Acetaminophen also relieves pain, although it does not have the anti-inflammatory effect that aspirin and NSAIDs do. Patients, especially older patients, who are taking acetaminophen or NSAIDs should be closely monitored for side effects. Aspirin should not be given to children to treat pain.
Opioids
Opioids are very effective for the relief of moderate to severe pain. Many patients with cancer pain, however, become tolerant to opioids during long-term therapy. Therefore, increasing doses may be needed to continue to relieve pain. A patient's tolerance of an opioid or physical dependence on it is not the same as addiction (psychological dependence). Mistaken concerns about addiction can result in undertreating pain.
Types of Opioids
There are several types of opioids. Morphine is the most commonly used opioid in cancer pain management. Other commonly used opioids include hydromorphone, oxycodone, methadone, fentanyl, and tramadol. The availability of several different opioids allows the doctor flexibility in prescribing a medication regimen that will meet individual patient needs.
Guidelines for Giving Opioids
Most patients with cancer pain will need to receive pain medication on a fixed schedule to manage the pain and prevent it from getting worse. The doctor will prescribe a dose of the opioid medication that can be taken as needed along with the regular fixed-schedule opioid to control pain that occurs between the scheduled doses. The amount of time between doses depends on which opioid the doctor prescribes. The correct dose is the amount of opioid that controls pain with the fewest side effects. The goal is to achieve a good balance between pain relief and side effects by gradually adjusting the dose. If opioid tolerance does occur, it can be overcome by increasing the dose or changing to another opioid, especially if higher doses are needed.
Cancer
Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start - for example, cancer that begins in the colon is called colon cancer; cancer that begins in basal cells of the skin is called basal cell carcinoma.
Cancer types can be grouped into broader categories. The main categories of cancer include:
Carcinoma - cancer that begins in the skin or in tissues that line or cover internal organs.
Sarcoma - cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
Leukemia - cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
Lymphoma and myeloma - cancers that begin in the cells of the immune system.
Central nervous system cancers - cancers that begin in the tissues of the brain and spinal cord.
Origins of Cancer
All cancers begin in cells, the body's basic unit of life. To understand cancer, it's helpful to know what happens when normal cells become cancer cells.
The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.
However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor.
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start - for example, cancer that begins in the colon is called colon cancer; cancer that begins in basal cells of the skin is called basal cell carcinoma.
Cancer types can be grouped into broader categories. The main categories of cancer include:
Carcinoma - cancer that begins in the skin or in tissues that line or cover internal organs.
Sarcoma - cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
Leukemia - cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
Lymphoma and myeloma - cancers that begin in the cells of the immune system.
Central nervous system cancers - cancers that begin in the tissues of the brain and spinal cord.
Origins of Cancer
All cancers begin in cells, the body's basic unit of life. To understand cancer, it's helpful to know what happens when normal cells become cancer cells.
The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.
However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor.
Not all tumors are cancerous; tumors can be benign or malignant.
Benign tumors aren't cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.
Malignant tumors are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis.
Some cancers do not form tumors. For example, leukemia is a cancer of the bone marrow and blood.
Cancer Statistics
A new report from the nation's leading cancer organizations shows that, for the first time since the report was first issued in 1998, both incidence and death rates for all cancers combined are decreasing for both men and women, driven largely by declines in some of the most common types of cancer.
Benign tumors aren't cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.
Malignant tumors are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis.
Some cancers do not form tumors. For example, leukemia is a cancer of the bone marrow and blood.
Cancer Statistics
A new report from the nation's leading cancer organizations shows that, for the first time since the report was first issued in 1998, both incidence and death rates for all cancers combined are decreasing for both men and women, driven largely by declines in some of the most common types of cancer.
Biological Therapy
Biological therapy (BYE-o-loj-ee-cal THER-ah-py) is a type of treatment that works with your immune system. It can help fight cancer or help control side effects (how your body reacts to the drugs you are taking) from other cancer treatments like chemotherapy.The immune system of the patient is treated in a bio therapy. It not only strengthens your immune system but also helps in ensuring that you are able fight against the side effects. In a bio therapy the therapist inserts some natural substances into the patient's body.The bio therapy drugs will perform two functions simultaneously. Firstly it will destroy the harmful cells responsible for diseases like cancer . Secondly it will segregate your regular cells from them. This will make sure that your body is able to function in a routine manner. Since these two tasks are performed simultaneously you will be able to get relief in a shorter period in biotherapy.Biotherapy treatment supplies natural substances to fight against diseases to the whole and to the affected region . The therapist identifies the energy levels in the infected area and then goes ahead with the therapy after calculating the amount to be supplemented. The success of bio therapy treatment also lies in allocating the appropriate amount of energy. If the energy levels are in excess or it is not supplied adequately the consequences will be severe. It takes less than a few hours to administer biological therapy. The treatement varies from case to case.Some minor problems may even be cured within 20 or 20 minutes though not in a single session. Most of the therapist will insist that you do a follow up by regular checkups to ensure that the energy levels remain constantly in the body at the same level.Bio therapy is very helpful to cure skin diseases and as well as regularize your digestive system.Bio therapy is well known for treating ailments like cancer. Cancer immunotherapy is not similar to the laser treatment provided for cancer patients. In a laser treatment the harmful cells are killed. But in a bio therapy the therapist kills the harmful substances and as well as makes sure that the routine functions of the normal cells are performed without any disturbances.
Thermography
Thermography is a tool which identifies breast cancer that uses super-sensitive infrared cameras and computer technology to detect heat on the surface of a patient’s breast. The presence of such heat is sometimes the result of intensive chemical and blood vessel activity that is characteristic of precancerous or cancerous tissue.Although some health professionals support the use of thermography (also known as digital infrared imaging).It may not detect small cancers or tumors deeper in the breast and it cannot pinpoint the location of a tumor. Two factors cause cancerous cells to generate heat that theoretically can be detected during thermography:Higher metabolic activity of cancer tissue compared to normal tissue. Cancer cells have higher rates of metabolism (physical and chemical processes in the body) than normal tissues. This higher metabolism registers as an increase in the surface temperature of the breast near the cancerous tissue. This is detected by the infrared camera.Angiogenesis. A cancerous tumor produces a chemical that promotes the development of blood vessels that supply the tumor with the nutrients it needs to keep growing. In addition, the cancer causes normal blood vessels to dilate (open) to provide even more blood to the forming tumor. Both of these activities produce additional heat which may be detected by the infrared camera.The infrared camera used during thermography converts infrared radiation emitted from the skin into electrical impulses and feeds the information into a computer. The computer analyzes the temperature and vascular (blood vessel) changes and produces high-resolution images known as thermograms. These images can be displayed on a monitor for analysis, with areas of raised temperature appearing red and areas of normal temperature appearing blue. They can also be printed or sent to another physician electronically.Thermography has been tested and researched since the 1950s. It originally involved the use of contact plates that measured the heat emitting from the breasts, although thermograms are now produced digitally. In 1982, the U.S FDA approved the use of thermography to help detect breast cancer and some circulation disorders, such as deep vein thrombosis and conditions relating to blood flow in the head and neck.Proponents of thermography claim that the technique can detect signs of precancerous or cancerous cells far earlier than other imaging techniques. For example, mammography technology cannot detect cancer until a tumor has actually begun to form, which may take several years. Thermography is designed to detect the formation of new blood vessels and chemical changes that occur very early in a tumor’s development. Some experts contend that thermography can identify signs of the formation of breast cancer up to 10 years before any other technique can detect them.In addition, thermography is touted as having certain advantages over traditional mammography procedures. During thermography, the machine does not touch the breast, in contrast to the squeezing of the breast that occurs during mammography. In addition, patients are not exposed to the potentially harmful radiation used in mammography.However, many experts have expressed doubts about the effectiveness of thermography in diagnosing breast cancer. For example, the American Cancer Society maintains that thermography is not a reliable diagnostic tool because it misses some cancers and has a high rate of false positives. The ACS warns that thermography should never be used as a replacement for mammograms.Other experts have also criticized thermography for producing too many false results, and have argued that the technique cannot detect the heat of cancers located deep in the breast or under fatty areas. It has also been noted that not all cancers emit heat, and thus would not be revealed by a thermogram.Still, some experts support thermography as a valuable tool in detecting breast cancers. Experts generally agree that thermography should not be used as a stand-alone diagnostic tool, but rather should be used with other diagnostic tools, such as mammograms, ultrasounds and physical examinations.
Friday, March 27, 2009
Medical Devices
A medical device is intended for use in:
- the diagnosis of disease or other conditions, or
- in the cure, mitigation, treatment, or prevention of disease,
- intended to affect the structure or any function of the body of man or other animals, and which does not achieve any of its primary intended purposes through chemical action and which is not dependent upon being metabolized for the achievement of any of its primary intended purposes.
Some examples include pacemakers, infusion pumps, the heart-lung machine, dialysis machines, artificial organs, implants, artificial limbs, corrective lenses, cochlear implants, ocular prosthetics, facial prosthetics, somato prosthetics, and dental implants.
Stereolithography is a practical example on how medical modeling can be used to create physical objects. Beyond modeling organs and the human body, emerging engineering techniques are also currently used in the research and development of new devices for innovative therapies, treatments, patient monitoring, and early diagnosis of complex diseases.
Medical devices can be regulated and classified (in the US) as shown below:
- Class I devices present minimal potential for harm to the user and are often simpler in design than Class II or Class III devices. Devices in this category include tongue depressors, bedpans, elastic bandages, examination gloves, and hand-held surgical instruments and other similar types of common equipment.
- Class II devices are subject to special controls in addition to the general controls of Class I devices. Special controls may include special labeling requirements, mandatory performance standards, and postmarket surveillance. Devices in this class are typically non-invasive and include x-ray machines, PACS, powered wheelchairs, infusion pumps, and surgical drapes.
- Class III devices require premarket approval, a scientific review to ensure the device's safety and effectiveness, in addition to the general controls of Class I. Examples include replacement heart valves, silicone gel-filled breast implants, implanted cerebellar stimulators, implantable pacemaker pulse generators and endosseous (intra-bone) implants.
Disciplines in biomedical engineering
- Bioelectrical and neural engineering
- Biomedical imaging and biomedical optics
- Biomaterials
- Biomechanics and biotransport
- Biomedical devices and instrumentation
- Molecular, cellular and tissue engineering
- Systems and integrative engineering
In other cases, disciplines within BME are broken down based on the closest association to another, more established engineering field, which typically include:
- Chemical engineering - often associated with biochemical, cellular, molecular and tissue engineering, biomaterials, and biotransport.
- Electrical engineering - often associated with bioelectrical and neural engineering, bioinstrumentation, biomedical imaging, and medical devices.
- Mechanical engineering - often associated with biomechanics, biotransport, medical devices, and modeling of biological systems.
- Optics and Optical engineering - biomedical optics, imaging and medical devices.
What is Biomedical Engineering?
Biomedical engineering (BME) is the application of engineering principles and techniques to the medical field. It combines the design and problem solving skills of engineering with medical and biological sciences to help improve patient health care and the quality of life of individuals.
As a relatively new discipline, much of the work in biomedical engineering consists of research and development, covering an array of fields: bioinformatics, medical imaging, image processing, physiological signal processing, biomechanics, biomaterials and bioengineering, systems analysis, 3-D modeling, etc. Examples of concrete applications of biomedical engineering are the development and manufacture of biocompatible prostheses, medical devices, diagnostic devices and imaging equipment such as MRIs and EEGs, and pharmaceutical drugs.
Computed tomography
Computed tomography (CT) is a medical imaging method employing tomography. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. The word "tomography" is derived from the Greek tomos (slice) and graphein (to write).
Computed tomography was originally known as the "EMI scan" as it was developed at a research branch of EMI, a company best known today for its music and recording business. It was later known as computed axial tomography (CAT or CT scan) and body section röntgenography.
CT produces a volume of data which can be manipulated, through a process known as windowing, in order to demonstrate various structures based on their ability to block the X-ray/Röntgen beam. Although historically (see below) the images generated were in the axial or transverse plane (orthogonal to the long axis of the body), modern scanners allow this volume of data to be reformatted in various planes or even as volumetric (3D) representations of structures.
Tissue E ngineering
One of the goals of tissue engineering is to create artificial organs for patients that need organ transplants. Biomedical engineers are currently researching methods of creating such organs. In one case bladders have been grown in lab and transplanted successfully into patients.Bioartificial organs, which utilize both synthetic and biological components, are also a focus area in research, such as with hepatic assist devices that utilize liver cells within an artificial bioreactor construct
Magnetic resonance imaging
Magnetic resonance imaging (MRI), or nuclear magnetic resonance imaging (NMRI), is primarily a medical imaging technique most commonly used in radiology to visualize the structure and function of the body. It provides detailed images of the body in any plane. MRI provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular, and oncological (cancer) imaging. Unlike CT, it uses no ionizing radiation, but uses a powerful magnetic field to align the nuclear magnetization of (usually) hydrogen atoms in water in the body. Radiofrequency fields are used to systematically alter the alignment of this magnetization, causing the hydrogen nuclei to produce a rotating magnetic field detectable by the scanner. This signal can be manipulated by additional magnetic fields to build up enough information to construct an image of the body.
MRI is a relatively new technology, which has been in use for little more than 30 years (compared with over 110 years for X-ray radiography). The first MR Image was published in 1973 and the first study performed on a human took place on July 3, 1977.
Magnetic resonance imaging was developed from knowledge gained in the study of nuclear magnetic resonance. In its early years the technique was referred to as nuclear magnetic resonance imaging (NMRI). However, as the word nuclear was associated in the public mind with ionizing radiation exposure it is generally now referred to simply as MRI. Scientists still use the term NMRI when discussing non-medical devices operating on the same principles. The term Magnetic Resonance Tomography (MRT) is also sometimes used. One of the contributors to modern MRI, Paul Lauterbur, originally named the technique zeugmatography, a Greek term meaning "that which is used for joining". The term referred to the interaction between the static, radiofrequency, and gradient magnetic fields necessary to create an image, but this term was not adopted.
Materials
Many different materials (natural and synthetic, biodegradable and permanent) have been investigated. Most of these materials have been known in the medical field before the advent of tissue engineering as a research topic, being already employed as bioresorbable sutures. Examples of these materials are collagen or some linear aliphatic polyesters.
New biomaterials have been engineered to have ideal properties and functional customization: injectability, synthetic manufacture, biocompatibility, non-immunogenicity, transparency, nano-scale fibers, low concentration, resorption rates, etc. PuraMatrix, originating from the MIT labs of Zhang, Rich, Grodzinsky and Langer is one of these new biomimetic scaffold families which has now been commercialized and is impacting clinical tissue engineering.
A commonly used synthetic material is PLA - polylactic acid. This is a polyester which degrades within the human body to form lactic acid, a naturally occurring chemical which is easily removed from the body. Similar materials are polyglycolic acid (PGA) and polycaprolactone (PCL): their degradation mechanism is similar to that of PLA, but they exhibit respectively a faster and a slower rate of degradation compared to PLA.
Scaffolds may also be constructed from natural materials: in particular different derivatives of the extracellular matrix have been studied to evaluate their ability to support cell growth. Proteic materials, such as collagen or fibrin, and polysaccharidic materials, like chitosan or glycosaminoglycans (GAGs), have all proved suitable in terms of cell compatibility, but some issues with potential immunogenicity still remains. Among GAGs hyaluronic acid, possibly in combination with cross linking agents (e.g. glutaraldehyde, water soluble carbodiimide, etc...), is one of the possible choices as scaffold material. Functionalized groups of scaffolds may be useful in the delivery of small molecules (drugs) to specific tissues
Biomedical engineering training
Education
Biomedical engineers combine sound knowledge of engineering and biological science, and therefore tend to have a bachelors of science and advanced degrees from major universities, who are now improving their biomedical engineering curriculum because interest in the field is increasing. Many colleges of engineering now have a biomedical engineering program or department from the undergraduate to the doctoral level. Traditionally, biomedical engineering has been an interdisciplinary field to specialize in after completing an undergraduate degree in a more traditional discipline of engineering or science, the reason for this being the requirement for biomedical engineers to be equally knowledgeable in engineering and the biological sciences. However, undergraduate programs of study combining these two fields of knowledge are becoming more widespread, including programs for a Bachelor of Science in Biomedical Engineering. As such, many students also pursue an undergraduate degree in biomedical engineering as a foundation for a continuing education in medical school. Though the number of biomedical engineers is currently low (as of 2004, under 10,000 in the U.S.), the number is expected to rise as modern medicine and technology improves.
In the U.S., an increasing number of undergraduate programs are also becoming recognized by ABET as accredited bioengineering/biomedical engineering programs. Over 40 programs are currently accredited by ABET.
Clinical Engineering
Clinical engineering is a branch of biomedical engineering related to the operation of medical equipment in a hospital setting. The tasks of a clinical engineer are typically the acquisition and management of medical device inventory, supervising biomedical engineering technicians (BMETs), ensuring that safety and regulatory issues are taken into consideration and serving as a technological consultant for any issues in a hospital where medical devices are concerned. Clinical engineers work closely with the IT department and medical physicists.
A typical biomedical engineering department does the corrective and preventive maintenance on the medical devices used by the hospital, except for those covered by a warranty or maintenance agreement with an external company. All newly acquired equipment is also fully tested. That is, every line of software is executed, or every possible setting is exercised and verified. Most devices are intentionally simplified in some way to make the testing process less expensive, yet accurate. Many biomedical devices need to be sterilized. This creates a unique set of problems, since most sterilization techniques can cause damage to machinery and materials. Most medical devices are either inherently safe, or have added devices and systems so that they can sense their failure and shut down into an unusable, thus very safe state. A typical, basic requirement is that no single failure should cause the therapy to become unsafe at any point during its life-cycle. See safety engineering for a discussion of the procedures used to design safe systems.
Monday, January 26, 2009
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