Portal:Medicine/Selected Article Archive (2007)

December 24, 2007 - December 31: Ambulance

An ambulance is a vehicle for transporting sick or injured people, to, from or between places of treatment for an illness or injury. The term ambulance is used to describe a vehicle used to bring medical care to patients outside of the hospital and when appropriate, to transport the patient to hospital for follow-up care and further testing. In some jurisdictions there is a modified form of the ambulance used, that only carries one member of ambulance crew to the scene to provide care, but is not used to transport the patient. In these cases a patient who requires transportation to hospital will require a patient-carrying ambulance to attend in addition to the fast responder.

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December 17, 2007 - December 24: Colorectal cancer

Colorectal cancer, also called colon cancer or bowel cancer, includes cancerous growths in the colon, rectum and appendix. It is the third most common form of cancer and the second leading cause of cancer-related death in the Western world. Colorectal cancer causes 655,000 deaths worldwide per year. Many colorectal cancers are thought to arise from adenomatous polyps in the colon. These mushroom-like growths are usually benign, but some may develop into cancer over time. The majority of the time, the diagnosis of localized colon cancer is through colonoscopy. Therapy is usually through surgery, which in many cases is followed by chemotherapy.

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December 10, 2007 - December 17: Cirrhosis

Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrotic scar tissue as well as regenerative nodules, leading to progressive loss of liver function. Cirrhosis is most commonly caused by alcoholism and hepatitis C, but has many other possible causes.

Ascites (fluid retention in the abdominal cavity) is the most common complication of cirrhosis and is associated with a poor quality of life, increased risk of infection, and a poor long-term outcome. Other potentially life-threatening complications are hepatic encephalopathy (confusion and coma) and bleeding from esophageal varices. Cirrhosis is generally irreversible once it occurs, and treatment generally focuses on preventing progression and complications. In advanced stages of cirrhosis the only option is a liver transplant.

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December 3, 2007 - December 10: Pregnancy test

A pregnancy test is a test to determine whether or not a woman is pregnant.

The earliest test for pregnancy is a rosette inhibition assay for early pregnancy factor (EPF). EPF can be detected in blood within 48 hours of fertilization. However, testing for EPF is expensive and time consuming.

Most chemical tests for pregnancy look for the presence of the beta subunit of hCG or human chorionic gonadotropin in the blood or urine. hCG can be detected in urine or blood after implantation, which occurs six to twelve days after fertilization.

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November 26, 2007 - December 3: Heart sounds

The heart sounds are the noises (sound) generated by the beating heart and the resultant flow of blood through it. This is also called a heartbeat. In cardiac auscultation, an examiner uses a stethoscope to listen for these sounds, which provide important information about the condition of the heart.

In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup), that occur in sequence with each heart beat. These are the first heart sound (S₁) and second heart sound (S₂), produced by the closure of the AV valves and semilunar valves respectively. In addition to these normal sounds, a variety of other sounds may be present including heart murmurs and adventitious sounds.

Heart murmurs are generated by turbulent flow of blood, which may occur inside or outside the heart. Murmurs may be physiological (benign) or pathological (abnormal). Abnormal murmurs can be caused by stenosis restricting the opening of a heart valve, causing turbulence as blood flows through it. Valve insufficiency (or regurgitation) allows backflow of blood when the incompetent valve is supposed to be closed. Different murmurs are audible in different parts of the cardiac cycle, depending on the cause of the murmur.

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November 19, 2007 - November 26: Aortic valve

The aortic valve has three cusps. These cusps are half moon shaped hence also called aortic semilunar valve. Each cusp has a small swelling in the center called the nodule. Dilatation of the wall of the aorta behind these cusps is called aortic sinus. When the aortic valve is open, the normal size of the orifice is 3-4 cm² in adults.

During ventricular systole, pressure rises in the left ventricle. When the pressure in the left ventricle rises above the pressure in the aorta, the aortic valve opens, allowing blood to exit the left ventricle into the aorta. When ventricular systole ends, pressure in the left ventricle rapidly drops. When the pressure in the left ventricle decreases, the aortic pressure forces the aortic valve to close. The closure of the aortic valve contributes the A component of the second heart sound.

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November 12, 2007 - November 19: Ulcerative colitis

Ulcerative colitis (Colitis ulcerosa, UC) is a form of inflammatory bowel disease (IBD). Ulcerative colitis is a form of colitis, a disease of the intestine, specifically the large intestine or colon, that includes characteristic ulcers, or open sores, in the colon. The main symptom of active disease is usually diarrhea mixed with blood, of gradual onset. Ulcerative colitis is, however, a systemic disease that affects many parts of the body outside the intestine. Because of the name, IBD is often confused with irritable bowel syndrome ("IBS"), a troublesome, but much less serious condition. Ulcerative colitis has similarities to Crohn's disease, another form of IBD. Ulcerative colitis is an intermittent disease, with periods of exacerbated symptoms, and periods that are relatively symptom-free. Although the symptoms of ulcerative colitis can sometimes diminish on their own, the disease usually requires treatment to go into remission.

Ulcerative colitis is a rare disease, with an incidence of about one person per 10,000 in North America. The disease tends to be more common in northern areas. Although ulcerative colitis has no known cause, there is a presumed genetic component to susceptibility. The disease may be triggered in a susceptible person by environmental factors. Although dietary modification may reduce the discomfort of a person with the disease, ulcerative colitis is not thought to be caused by dietary factors. Although ulcerative colitis is treated as though it were an autoimmune disease, there is no consensus that it is such. Treatment is with anti-inflammatory drugs, immunosuppression (suppressing the immune system), and biological therapy targeting specific components of the immune response. Colectomy (partial or total removal of the large bowel through surgery) is occasionally necessary, and is considered to be a cure for the disease.

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November 5, 2007 - November 12: Henrietta Lacks

Henrietta Lacks (August 18, 1920 – October 4, 1951) was the involuntary donor of cells from her cancerous tumor, which were cultured by George Otto Gey to create an immortal cell line for medical research. This is now known as the HeLa cell line.

She was born as Henrietta Pleasant on August 18, 1920 in Roanoke, Virginia to Eliza (1886–1924) and John Randall Pleasant I (1881–1969). Eliza died giving birth to her tenth child in 1924. Sometime after his wife's death, John Pleasant took the children back to where their relatives on their mother's side lived, and where they were raised. In 1929, a 48 year old John, still living in Roanoke at 12th Street Southwest, married a 13-year-old girl named Lillian. John worked as a brakeman on the railroad.

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October 29, 2007 - November 5: Eye

Eyes are organs of vision that detect light. Different kinds of light-sensitive organs are found in a variety of organisms. The simplest eyes do nothing but detect whether the surroundings are light or dark, while more complex eyes can distinguish shapes and colors. The visual fields of some such complex eyes largely overlap, to allow better depth perception (binocular vision), as in humans; and others are placed so as to minimize the overlap, such as in rabbits and chameleons.

In most vertebrates and some mollusks, the eye works by allowing light to enter it and project onto a light-sensitive panel of cells known as the retina at the rear of the eye, where the light is detected and converted into electrical signals. These are then transmitted to the brain via the optic nerve. Such eyes are typically roughly spherical, filled with a transparent gel-like substance called the vitreous humour, with a focusing lens and often an iris which regulates the intensity of the light that enters the eye. The eyes of cephalopods, fish, amphibians and snakes usually have fixed lens shapes, and focusing vision is achieved by telescoping the lens—similar to how a camera focuses.

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October 22, 2007 - October 29: Heart

The heart is a muscular organ responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in the annelids, mollusks, and arthropods. The term cardiac (as in cardiology) means "related to the heart" and comes from the Greek καρδία, kardia, for "heart." The heart is composed of cardiac muscle, an involuntary muscle tissue which is found only within this organ. The average human heart beating at 72 BPM, will beat approximately 2.5 billion times during a lifetime of 66 years.

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October 15, 2007 - October 22: Magnetic resonance imaging

Magnetic resonance imaging (MRI), formerly referred to as magnetic resonance tomography (MRT) and, in scientific circles and as originally marketed by companies such as General Electric, Nuclear Magnetic Resonance Imaging (NMRI) or NMR zeugmatography imaging, is a non-invasive method used to render images of the inside of an object. It is primarily used in medical imaging to demonstrate pathological or other physiological alterations of living tissues. MRI also has uses outside of the medical field, such as detecting rock permeability to hydrocarbons and as a non-destructive testing method to characterize the quality of products such as produce and timber.

MRI should not be confused with the NMR spectroscopy technique used in chemistry, although both are based on the same principles of nuclear magnetic resonance. In fact MRI is NMR applied to the signal from water to acquire spatial information in place of chemical information about molecules. The same equipment can be used for both imaging and spectroscopy.

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October 8, 2007 - October 15: Radiology

Radiology is the medical specialty directing medical imaging technologies to diagnose and sometimes treat diseases. Originally it was the aspect of medical science dealing with the medical use of electromagnetic energy emitted by X-ray machines or other such radiation devices for the purpose of obtaining visual information as part of medical imaging. Radiology that involves use of x-ray is called roentgenology. Today, following extensive training, radiologists direct an array of imaging technologies (such as ultrasound, computed tomography (CT) and magnetic resonance imaging) to diagnose or treat disease. Interventional radiology is the performance of (usually minimally invasive) medical procedures with the guidance of imaging technologies. The acquisition of medical imaging is usually carried out by the radiographer or radiologic technologist. Outside of the medical field, radiology also encompasses the examination of the inner structure of objects using X-rays or other penetrating radiation.

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October 1, 2007 - October 8: Morphine

Morphine (INN) (IPA: [ˈmɔ(ɹ)fin]) is a highly potent opiate analgesic drug and is the principal active agent in opium and the prototypical opioid. Like other opiates, e.g. diacetylmorphine (heroin), morphine acts directly on the central nervous system (CNS) to relieve pain, and at synapses of the nucleus accumbens in particular. Studies done on the efficacy of various opioids have indicated that, in the management of severe pain, no other narcotic analgesic is more effective or superior to morphine. Morphine is highly addictive when compared to other substances, and tolerance, physical and psychological dependences develop very rapidly.

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September 24, 2007 - October 1: Osteoarthritis

Osteoarthritis / Osteoarthrosis (OA, also known as degenerative arthritis, degenerative joint disease, arthrosis or in more colloquial terms "wear and tear"), is a condition in which low-grade inflammation results in pain in the joints, caused by wearing of the cartilage that covers and acts as a cushion inside joints. As the bone surfaces become less well protected by cartilage, the patient experiences pain upon weight bearing, including walking and standing. Due to decreased movement because of the pain, regional muscles may atrophy, and ligaments may become more lax. OA is the most common form of arthritis.

OA affects nearly 21 million people in the United States, accounting for 25% of visits to primary care physicians, and half of all NSAID (Non-Steroidal Anti-Inflammatory Drugs) prescriptions. It is estimated that 80% of the population will have radiographic evidence of OA by age 65, although only 60% of those will be symptomatic.

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September 17, 2007 - September 24.: Inflammation

Inflammation (Latin, inflammatio, to set on fire) is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. It is a protective attempt by the organism to remove the injurious stimuli as well as initiate the healing process for the tissue. Inflammation is not a synonym for infection. Even in cases where inflammation is caused by infection it is incorrect to use the terms as synonyms: infection is caused by an exogenous pathogen, while inflammation is the response of the organism to the pathogen.

In the absence of inflammation, wounds and infections would never heal and progressive destruction of the tissue would compromise the survival of the organism. However, inflammation which runs unchecked can also lead to a host of diseases, such as hay fever, atherosclerosis, and rheumatoid arthritis. It is for this reason that inflammation is normally tightly regulated by the body.

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September 10, 2007 - September 17.: Rudolf Virchow

Rudolf Ludwig Karl Virchow (born October 13, 1821, in Schivelbein (Pomerania); died September 5, 1902, in Berlin) was a German doctor, anthropologist, public health activist, pathologist, prehistorian, biologist and politician. He is referred to as the "Father of Pathology".

From a farming family of relatively modest means, Virchow studied medicine in Berlin at the military academy of Prussia on a scholarship. When he graduated in 1842 he went to serve as Robert Froriep's assistant at the Berlin Charité rather than the expected military service. One of his major contributions to German medical education was to encourage the use of microscopes by medical students and was known for constantly urging his students to 'think microscopically'. The campus where this Charité hospital is located is named after him, the Campus Virchow Klinikum.

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September 3, 2007 - September 10.: Gene therapy

Gene therapy is the insertion of genes into an individual's cells and tissues to treat a disease, and hereditary diseases in which a defective mutant allele is replaced with a functional one. Although the technology is still in its infancy, it has been used with some success. Antisense therapy is not strictly a form of gene therapy, but is a genetically-mediated therapy and is often considered together with other methods.

In the 1980s, advances in molecular biology had already enabled human genes to be sequenced and cloned. Scientists looking for methods of easily producing proteins — such as insulin, the protein deficient in diabetes mellitus type 1 — investigated introducing human genes to bacterial DNA. The modified bacteria then produce the corresponding protein, which can be harvested and injected in people who cannot produce it naturally.

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August 27, 2007 - September 3.: Artificial heart

An artificial heart is a prosthetic device that is implanted into the body to replace the biological heart. It is distinct from a cardiopulmonary bypass machine (CPB), which is an external device used to provide the functions of both the heart and the lungs. The CPB oxygenates the blood, so does not need to be connected to both blood circuits. Also, a CPB is only suitable for a few hours use, while artificial hearts have so far been used for periods of long over a year (as of 2007).

A synthetic replacement for the heart remains one of the long-sought holy grails of modern medicine. The obvious benefit of a functional artificial heart would be to lower the need for heart transplants, because the demand for donor hearts (as it is for all organs) always greatly exceeds supply.

Although the heart is conceptually simple (basically a muscle that functions as a pump), it embodies subtleties that defy straightforward emulation with synthetic materials and power supplies. Consequences of these issues include severe foreign-body rejection and external batteries that limit patient mobility. These complications limited the lifespan of early human recipients to hours or days.

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August 20, 2007 - August 27.: Artificial pacemaker

A pacemaker (or artificial pacemaker, so as not to be confused with the heart's natural pacemaker) is a medical device which uses electrical impulses, delivered by electrodes contacting the heart muscles, to regulate the beating of the heart. The primary purpose of a pacemaker is to maintain an adequate heart rate, either because the heart's native pacemaker is not fast enough, or there is a block in the heart's electrical conduction system. Modern pacemakers are externally programmable and allow the cardiologist to select the optimum pacing modes for individual patients. Some combine a pacemaker and implantable defibrillator in a single implantable device. Others have multiple electrodes stimulating differing positions within the heart to improve synchronisation of the lower chambers of the heart.

In 1889 J A McWilliam reported in the British Medical Journal of his experiments in which application of an electrical impulse to the human heart in asystole caused a ventricular contraction and that a heart rhythm of 60-70 beats per minute could be evoked by impulses applied at spacings equal to 60-70/minute.

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August 13, 2007 - August 20.: X-ray

An X-ray picture (radiograph), taken by Wilhelm Röntgen in 1896, of His wife's hand]] X-rays (or Röntgen rays) are a form of electromagnetic radiation with a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 to 30 000 PHz (1 PHz = 10¹⁵ Hertz). X-rays are primarily used for diagnostic radiography and crystallography. X-rays are a form of ionizing radiation and as such can be dangerous. In many languages it is called Röntgen radiation after one of the first investigators of the X-rays, Wilhelm Conrad Röntgen.

The unit of measure for an X-ray is called a rem, abbreviated "r". A rem is a relatively large amount, and therefore exposure to X-rays for medical use is often measured in mrems (or millirems).

The average person living in the United States is exposed to approximately 360 mrem annually from background sources alone.

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August 6, 2007 - August 13.: History of medicine

All human societies have medical beliefs that provide explanations for, and responses to birth, death, and disease. Throughout the world, illness has often been attributed to witchcraft, demons, averse astral influence, or the will of the gods, ideas that retain some power, with faith healing and shrines still common, although the rise of scientific medicine in the past two centuries has altered or replaced many historic health practices.

There is no actual record of when the use of plants for medicinal purposes first started, although the first generally accepted use of plants as healing agents were depicted in the cave paintings discovered in the Lascaux caves in France, which have been Radiocarbon dated to between 13,000 - 25,000 BC.

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July 30, 2007 - August 6.: Autism

Autism is a brain development disorder that shows symptoms before a child is three years old and has a steady course with no remission. Its characteristic signs are impairments in social interaction and communication, as well as restricted and repetitive behavior. These characteristics distinguish autism from milder pervasive developmental disorders (PDD) or autism spectrum disorders (ASD), and reflect Leo Kanner's first descriptions of autism, which emphasized "autistic aloneness" and "insistence on sameness".

Heritability contributes about 90% of the risk of a child developing autism, but the genetics of autism are complex and typically it is unclear which genes are responsible. In rare cases, autism is strongly associated with agents that cause birth defects. Many other causes have been proposed, such as exposure of children to vaccines; these proposals are controversial and the vaccine hypotheses have no convincing scientific evidence.

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July 23, 2007 - July 30.: Theobromine

Theobromine, also known as xantheose, is a bitter alkaloid of the cacao plant, and is therefore found in chocolate. It is in the methylxanthine class of chemical compounds, which also includes the similar compounds theophylline and caffeine. Despite its name, the compound contains no bromine — theobromine is derived from Theobroma, the name of the genus of the cacao tree, (which itself is made up of the Greek roots theo ("God") and broma ("food"), meaning "food of the gods") with the suffix -ine given to alkaloids and other basic nitrogen-containing compounds.

Theobromine is a water insoluble, crystalline, bitter powder; the colour has been listed as either white or colourless.

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July 16, 2007 - July 23.: Evolution of sex

The evolution of sex is a major puzzle in modern evolutionary biology. Many groups of organisms, notably the majority of animals and plants, reproduce sexually. The evolution of sex contains two related, yet distinct, themes: its origin and its maintenance. However, since the hypotheses for the origins of sex are difficult to test experimentally, most current work has been focused on the maintenance of sexual reproduction. Several explanations have been suggested by biologists including W. D. Hamilton, Alexey Kondrashov, and George C. Williams to explain how sexual reproduction is maintained in a vast array of different living organisms.

It seems that a sexual cycle is maintained because it improves the quality of progeny (fitness), despite reducing the overall number of offspring (twofold cost of sex). In order for sex to be evolutionarily advantageous, it must be associated with a significant increase in the fitness of offspring.

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July 9, 2007 - July 16.: Metformin

Metformin (INN; trade names Glucophage, Diabex, Diaformin, Fortamet, Riomet, Glumetza and others) is an anti-diabetic drug from the biguanide class of oral antihyperglycemic agents. Other biguanides include the withdrawn agents phenformin and buformin. Metformin is the most popular anti-diabetic drug in the United States and one of the most prescribed drugs overall, with nearly 35 million prescriptions filled in 2006 for generic metformin alone.

The biguanide class of anti-diabetic drugs originates from the French lilac (Galega officinalis), a plant known for several centuries to reduce the symptoms of diabetes mellitus. (More...)

July 2, 2007 - July 9.: Genetic code

The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells. Specifically, the code defines a mapping between tri-nucleotide sequences called codons and amino acids; every triplet of nucleotides in a nucleic acid sequence specifies a single amino acid. Because the vast majority of genes are encoded with exactly the same code (see #RNA codon table), this particular code is often referred to as the canonical or standard genetic code, or simply the genetic code, though in fact there are many variant codes (thus, the canonical genetic code is not universal). For example, in humans, protein synthesis in mitochondria relies on a genetic code that varies from the canonical code. (More...)

June 25, 2007 - July 2.: Lung cancer

Lung cancer is the malignant transformation and expansion of lung tissue, and is responsible for 1.3 million deaths worldwide annually. It is the most common cause of cancer-related death in men, and the second most common in women.

Current research indicates that the factor with the greatest impact on risk of lung cancer is long-term exposure to inhaled carcinogens, especially tobacco smoke. While some people who have never smoked do still get lung cancer, this appears to be due to a combination of genetic factors and exposure to secondhand smoke. Radon gas and air pollution may also contribute to the development of lung cancer.

Treatment and prognosis depend upon the histological type of cancer, the stage (degree of spread), and the patient's performance status. Treatments include surgery, chemotherapy, and radiotherapy. (More...)

June 18, 2007 - June 25: Herpes zoster

Herpes zoster, colloquially known as shingles, is the reactivation (from the general area of the spinal cord) of varicella zoster virus (VZV, primary infection of which leads to chickenpox), one of the Herpesviridae group, leading to a crop of painful blisters over the area of a dermatome. In Italy and in Malta, it is sometimes referred to as "St. Anthony's fire", although that name usually refers to ergotism. Shingles, or herpes zoster, is a neurological disease. affecting the nervous system, with or without the appearance of a rash on the skin. (More...)

June 12, 2007 - June 18: Renal tubular acidosis

Renal tubular acidosis (RTA) is a medical condition that involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine. When blood is filtered by the kidney, the filtrate passes through the tubules of the nephron, allowing for exchange of salts, acid equivalents, and other solutes before it drains into the bladder as urine. The metabolic acidosis that results from RTA may be caused either by failure to recover sufficient (alkaline) bicarbonate ions from the filtrate in the early portion of the nephron (proximal tubule) or by insufficient secretion of (acid) hydrogen ions into the latter portions of the nephron (distal tubule). Although a metabolic acidosis also occurs in those with renal insufficiency, the term RTA is reserved for individuals with poor urinary acidification in otherwise well-functioning kidneys. Several different types of RTA exist, which all have different syndromes and different causes. (More...)

June 5, 2007 - June 12: Henipavirus

Henipavirus is a genus of the family Paramyxoviridae, order Mononegavirales containing two members, Hendravirus and Nipahvirus. The henipaviruses are naturally harboured by Pteropid fruit bats (flying foxes) and are characterised by a large genome, a wide host range and their recent emergence as zoonotic pathogens capable of causing illness and death in domestic animals and humans.

Henipaviruses are pleomorphic (variably shaped), ranging in size from 40 to 600 nm in diameter. They possess a lipid membrane overlying a shell of viral matrix protein. At the core is a single helical strand of genomic RNA tightly bound to N (nucleocapsid) protein and associated with the L (large) and P (phosphoprotein) proteins which provide RNA polymerase activity during replication. (More...)

May 28, 2007 - June 5: Doxorubicin

Doxorubicin (trade name Adriamycin) or hydroxyldaunorubicin is a DNA-interacting drug widely used in chemotherapy. It is an anthracycline antibiotic and structurely closely related to daunomycin, and also intercalates DNA. It is commonly used in the treatment of a wide range of cancers.

The drug is administered by injection, and may be sold under the brand names Adriamycin PFS, Adriamycin RDF, or Rubex. Doxil is a liposome-encapsulated dosage form of doxorubicin made by Ben Venue Laboratories for Johnson & Johnson. The main benefits of this form are a reduction in cardiotoxicity. (More...)

May 21, 2007 - May 28: Maxillary central incisor

Labial view.

The maxillary central incisor is a human tooth in the front upper jaw, or maxilla, and is usually the most visible of all teeth in the mouth. It is located mesial (closer to the midline of the face) to the maxillary lateral incisor. As with all incisors, their function is for shearing or cutting food during mastication (chewing). There are no cusps on the teeth. Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge. Formation of these teeth begin at 14 weeks in utero for the deciduous (baby) set and 3–4 months of age for the permanent set.

There are some minor differences between the deciduous maxillary central incisor and that of the permanent maxillary central incisor. The deciduous tooth appears in the mouth at 10 months of age and is replaced by the permanent tooth around 7–8 years of age. The permanent tooth is larger and is longer than it is wide. The maxillary central incisors contact each other at the midline of the face. (More...)

May 14, 2007 - May 21: Ambulance

An ambulance is a vehicle for transporting people to, from or between places of treatment for an illness or injury. In the modern context it is also the vehicle commonly used to bring medical care to patients outside of the hospital and, when appropriate, to transport the patient to hospital for follow-up care and further testing. There is also a modified form of the ambulance used in several jurisdictions that only carries one member of ambulance crew to the scene to provide care but is not used to transport the patient. In these cases a patient who requires transportation to hospital will require a patient carrying ambulance to attend in addition to the fast responder.

The term ambulance comes from the Latin word ambulare, meaning to walk or move about which is a reference to early medical care where patients were moved by lifting or wheeling. The word is most commonly associated with the land-based, motorized emergency vehicles that administer emergency care to those with acute illnesses or injuries, hereafter known as emergency ambulances. These are usually fitted with flashing warning lights and sirens to facilitate their movement through traffic. (More...)

May 7, 2007 - May 14: Measles

Measles, also known as rubeola, is a disease caused by a virus, specifically a paramyxovirus of the genus Morbillivirus.

Reports of measles go back to at least 600 BCE, however, the first scientific description of the disease and its distinction from smallpox is attributed to the Persian physician Ibn Razi (Rhazes) 860-932 who published a book entitled "Smallpox and Measles" (in Arabic: Kitab fi al-jadari wa-al-hasbah). In 1954, the virus causing the disease was isolated, and licensed vaccines to prevent the disease became available in 1963.

Measles is spread through respiration (contact with fluids from an infected person's nose and mouth, either directly or through aerosol transmission), and is highly contagious—90% of people without immunity sharing a house with an infected person will catch it. Airborne precautions should be taken for all suspected cases of measles. (More...)

April 30, 2007 - May 7: Psychoactive drug

An assortment of psychoactive drugs

A psychoactive drug or psychotropic substance is a chemical substance that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood, consciousness and behavior. These drugs may be used recreationally to purposefully alter one's consciousness, as entheogens for ritual or spiritual purposes, or as medication.

Many of these substances (especially the stimulants and depressants) can be habit-forming, causing chemical dependency and may lead to substance abuse. Conversely, others (namely the psychedelics) can help to treat and even cure such addictions. (More...)

April 23, 2007 - April 30: Coeliac disease

Biopsy of small bowel showing coeliac disease manifested by blunting of villi, crypt hyperplasia, and lymphocyte infiltration of crypts.

Coeliac disease or celiac disease is an autoimmune disorder of the small bowel that occurs in genetically predisposed individuals in all age groups after early infancy. Symptoms may include diarrhoea, failure to thrive (in children) and fatigue, but these may be absent and associated symptoms in all other organ systems have been described. It affects approximately 1% of Caucasian populations, though it is significantly underdiagnosed. A growing portion of diagnoses are being made in asymptomatic persons as a result of increasing screening.

Coeliac disease is caused by a reaction to gliadin, a gluten protein found in wheat (and similar proteins of the tribe Triticeae which includes other cultivars such as barley and rye). Upon exposure to gliadin, the enzyme tissue transglutaminase modifies the protein, and the immune system cross-reacts with the bowel tissue, causing an inflammatory reaction. That leads to flattening of the lining of the small intestine, which interferes with the absorption of nutrients. The only effective treatment is a lifelong gluten-free diet. (More...)

April 16, 2007 - April 23: Cholangiocarcinoma

Yellowing of the skin and eyes (jaundice)

Cholangiocarcinoma is a cancer of the bile ducts, which drain bile from the liver into the small intestine. It is a relatively rare cancer, with an annual incidence of 1–2 cases per 100,000 in the Western world, but rates of cholangiocarcinoma have been rising worldwide over the past several decades. Risk factors for cholangiocarcinoma include primary sclerosing cholangitis (an inflammatory disease of the bile ducts), congenital liver malformations, infection with the parasitic liver flukes Opisthorchis viverrini or Clonorchis sinensis, and exposure to Thorotrast (thorium dioxide), a chemical previously used in medical imaging. The symptoms of cholangiocarcinoma include jaundice, weight loss, and sometimes generalized itching. The disease is diagnosed through a combination of blood tests, imaging, endoscopy, and sometimes surgical exploration.

Surgery is the only potentially curative treatment, but most patients have advanced and inoperable disease at the time of diagnosis. After surgery, adjuvant chemotherapy or radiation therapy may be given to increase the chances of cure. Patients with advanced and inoperable cholangiocarcinoma are generally treated with chemotherapy and palliative care measures. Areas of ongoing medical research in cholangiocarcinoma include the use of newer targeted therapies (such as erlotinib) and the use of photodynamic therapy. (More...)

April 9, 2007 - April 16: Pathology

Pathology (from Greek pathos, feeling, pain, suffering; and logos, study of; see also -ology) is the study and diagnosis of disease through examination of molecules, cells, tissues and organs. The term encompasses both the medical specialty which uses tissues and body fluids to obtain clinically useful information, as well as the related scientific study of disease processes.

The histories of both investigative and medical pathology can be traced to the earliest application of the scientific method to the field of medicine, a development which occurred in Western Europe during the Italian Renaissance. Most early pathologists were also practicing physicians or surgeons. Like other medical fields, pathology has become more specialized with time, and most pathologists today do not practice in other areas of medicine. (More...)

April 2, 2007 - April 9: International Red Cross and Red Crescent Movement

The International Red Cross and Red Crescent Movement is an international humanitarian movement whose stated mission is to protect human life and health, to ensure respect for the human being, and to prevent and alleviate human suffering, without any discrimination based on nationality, race, religious beliefs, class or political opinions.

The often-heard term International Red Cross is actually a misnomer, as no official organization as such exists bearing that name. In reality, the movement consists of several distinct organizations that are legally independent from each other, but are united within the Movement through common basic principles, objectives, symbols, statutes, and governing organs.

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March 26, 2007 - April 2: 2007 Bernard Matthews H5N1 outbreak

The 2007 Bernard Matthews H5N1 outbreak was an occurrence of avian flu in England that began on January 30, 2007. The infection was caused by the H5N1 subtype of the Influenza A virus and occurred at one of Bernard Matthews' farms in Holton in Suffolk. A range of precautions were instituted including a large cull of turkeys, the imposition of segregation zones, and a disinfection programme for the plant.

Though the cause of the outbreak was not determined, Bernard Matthews regularly transports turkeys and turkey products between the UK and its plant in Hungary, and the H5N1 bird flu strains found in Hungary and Britain are effectively genetically identical. (More...)

March 19, 2007 - March 26: Crohn's disease

Crohn's disease (also known as regional enteritis) is a chronic, episodic, inflammatory condition of the gastrointestinal tract characterized by transmural inflammation (affecting the entire wall of the involved bowel) and skip lesions (areas of inflammation with areas of normal lining in between). Crohn's disease is a type of inflammatory bowel disease (IBD) and may sometimes affect any part of the gastrointestinal tract from mouth to anus; as a result, the symptoms of Crohn's disease can vary between affected individuals. The main gastrointestinal symptoms are abdominal pain, diarrhea, which may be bloody, and weight loss. Crohn's disease can also cause complications outside of the gastrointestinal tract such as skin rashes, arthritis, and inflammation of the eye. (More...)

March 12, 2007 - March 19: Endoscopic foreign body retrieval

Endoscopic foreign body retrieval refers to the removal of ingested objects from the esophagus, stomach and duodenum by endoscopic techniques. It does not involve surgery, but rather encompasses a variety of techniques employed through the gastroscope for grasping foreign bodies, manipulating them, and removing them while protecting the esophagus and trachea.

It is of particular importance with children, people with mental illness and prison inmates as these groups have a high rate of foreign body ingestion. (More...)

March 5, 2007 - March 12: Anabolic Androgenic Steroids

Anabolic androgenic steroids are a class of natural and synthetic steroid hormones that promote cell growth and division, resulting in growth of several types of tissues, especially muscle and bone. Different anabolic androgenic steroids have varying combinations of androgenic and anabolic properties, and are often referred to in medical texts as AAS (anabolic/androgenic steroids). Anabolism is the metabolic process that builds larger molecules from smaller ones.

Anabolic steroids were first discovered in the early 1930s and have since been used for numerous medical purposes including stimulation of bone growth, appetite, puberty, and muscle growth. The most widespread use of anabolic steroids is their use for chronic wasting conditions, such as cancer and AIDS. Anabolic steroids can produce numerous physiological effects including increases in protein synthesis, muscle mass, strength, appetite and bone growth. (More...)

February 26, 2007 - March 5: Vacutainer

Vacutainer was developed in 1947 by Joseph Kleiner. The vein is first punctured with the hypodermic needle, which is connected to a translucent plastic holder. The needle actually has a second, smaller needle, and when a Vacutainer test tube is pushed down into the holder, its rubber cap is pierced. The vacuum in the tube sucks blood though the needle and fills itself. The tube is then removed and another can be inserted and filled the same way. It is important to remove the tube before withdrawing the needle, as there may still be some suction left, causing pain upon withdrawal. (More...)

February 19, 2007 - February 26: Nutrition

Nutrition science studies the relationship between diet and states of health and disease. Dieticians are health professionals who are specialized in this area of expertise, highly trained to provide safe, evidence-based dietary advice and interventions.

There is a spectrum ranging from malnutrition to optimal health, including many common symptoms and diseases which can often be prevented or alleviated with better nutrition.

Deficiencies, excesses and imbalances in diet can produce negative impacts on health, which may lead to diseases such as scurvy, obesity or osteoporosis, as well as psychological and behavioral problems. Moreover, excessive ingestion of elements that have no apparent role in health, (e.g. lead, mercury, PCBs, dioxins), may incur toxic and potentially lethal effects, depending on the dose. The science of nutrition attempts to understand how and why specific dietary aspects influence health. (More...)

February 12, 2007 - February 19: Insulin

Insulin (from Latin insula, "island", as it is produced in the Islets of Langerhans in the pancreas) is a polypeptide hormone that regulates carbohydrate metabolism. Apart from being the primary agent in carbohydrate homeostasis, it has effects on fat metabolism and it changes the liver's activity in storing or releasing glucose and in processing blood lipids, and in other tissues such as fat and muscle. The amount of insulin in circulation has extremely widespread effects throughout the body.

Insulin is used medically to treat some forms of diabetes mellitus. Patients with type 1 diabetes mellitus depend on external insulin (most commonly injected subcutaneously) for their survival because of an absolute deficiency of the hormone. Patients with type 2 diabetes mellitus have insulin resistance, relatively low insulin production or both; some type 2 diabetics eventually require insulin when other medications become insufficient in controlling blood glucose levels. (More...)

February 5, 2007 - February 12: Spanish flu

The 1918 flu pandemic was an influenza pandemic between 1918 and 1920 caused by an unusually severe and deadly strain of the subtype H1N1 of the species Influenza A virus. By far the most destructive influenza pandemic in history, it killed some 50 million to 100 million people worldwide (2.5 – 5% of the human population) in just 18 months, dwarfing the simultaneous bloodshed due to World War I. Furthermore, many of its victims were healthy young adults, in contrast to most influenza outbreaks which predominantly affect juvenile, elderly, or otherwise weakened patients.

Despite not having originated in Spain, the Allies of World War I came to call it the Spanish Flu. This was mainly because the pandemic received greater press attention in Spain than in the rest of the world, as Spain was not involved in the war and had not imposed wartime censorship. (More...)

January 29, 2007 - February 5: Abortion

An abortion is the removal or expulsion of an embryo or fetus from the uterus, resulting in or caused by its death. This can occur spontaneously as a miscarriage, or be artificially induced by chemical, surgical or other means. Commonly, "abortion" refers to an induced procedure at any point during pregnancy; medically, it is defined as miscarriage or induced termination before twenty weeks' gestation, which is considered nonviable.

Throughout history abortion has been induced by various methods. The moral and legal aspects of abortion are subject to intense debate in many parts of the world. (More...)

January 22, 2007 - January 29: Schatzki ring

A Schatzki ring or Schatzki-Gary ring is a ring found in the lower part of the esophagus that can cause difficulty swallowing. The ring is made up of mucosal tissue (which lines the esophagus) or muscular tissue. Patients with Schatzki rings can develop intermittent dysphagia or difficulty swallowing, or more seriously, with a completely blocked esophagus. The ring is named after the American physician, Richard Schatzki. (More...)

January 15, 2007 - January 21: Asperger syndrome

Asperger syndrome (AS) is one of five neurobiological pervasive developmental disorders (PDD) that is characterized by deficiencies in social and communication skills. It is considered to be part of the autistic spectrum and is differentiated from other PDDs and from high functioning autism (HFA) in that early development is normal and there is no language delay. The diagnosis of AS is complicated by the lack of adoption of a standardized diagnostic screen, and, instead, the use of several different screening instruments and sets of diagnostic criteria. The exact cause of AS is unknown and the prevalence is not firmly established, due partly to the use of differing sets of diagnostic criteria.

Asperger syndrome is often not identified in early childhood, and many individuals do not receive diagnosis until after puberty or when they are adults. Assistance for core symptoms of AS consists of therapies that apply behavior management strategies and address poor communication skills, obsessive or repetitive routines, and physical clumsiness. Many individuals with AS can adopt strategies for coping and do lead fulfilling lives - being gainfully employed, getting married or having successful relationships, and having families. In most cases, they are aware of their differences and recognize when they need support to maintain an independent life. (More...)

January 8, 2007 - January 14: Human genome

The human genome is the genome of Homo sapiens, which is composed of 24 distinct chromosomes (22 autosomal + X + Y) with a total of approximately 3 billion DNA base pairs containing an estimated 20,000-25,000 genes. The Human Genome Project produced a reference sequence of the euchromatic human genome, which is used worldwide in biomedical sciences. The human genome is much more gene-sparse than was initially predicted at the outset of the Human Genome Project, with only about 1.5% of the total length serving as protein-coding exons. (More...)

January 1, 2007 - January 7: Blood type

A total of 29 human blood group systems are recognized by the International Society of Blood Transfusion (ISBT). The most significant of these are the ABO blood group system and the Rhesus blood group system.

Each blood group is represented by a substance on the surface of red blood cells (RBCs). These substances are important because they contain specific sequences of amino acid and carbohydrate that are antigenic. As well as being on the surface of RBCs, some of these antigens are also present on the cells of other tissues. (More...)