Portal:Medicine/Selected Article Archive
Selected articles
Today, June 18, 2025, is in week number 25.
Selected articles have Template:MedportalSA on their talk pages.
The following articles were selected for display on Portal:Medicine:
August 15., 2006 - August 22.
Paracetamol (INN) (IPA: [pærəˈsitəmɒl, -moʊl, -ˈsɛtə-]) or acetaminophen (USAN) (brand names Tylenol® in US and Panadol® in UK), is a common analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains. Paracetamol is also useful in managing more severe pain, allowing lower dosages of additional NSAID or opioid analgesics to be used, so minimising overall side-effects. It is a major ingredient in numerous cold and flu medications and many prescription analgesics. It is remarkably safe in recommended doses, but because of its wide availability, deliberate or accidental overdoses are fairly common.
The words acetaminophen and paracetamol both come from the chemical names for the compound: N-acetyl-para-aminophenol and para-acetyl-amino-phenol. In some contexts, it is shortened to apap, for N-acetyl-para-amino-phenol. (More...)
August 7., 2006 - August 14.
Tooth enamel is the hardest and most highly mineralized substance of the body, and with dentin, cementum, and dental pulp is one of the four major parts of the tooth. It is the normally visible dental tissue of a tooth and must be supported by underlying dentin. Ninety-six per cent of enamel consists of minerals, with water and organic material composing the rest. The normal color of enamel varies from light yellow to grayish white. At the edges of teeth where there is no dentin underlying the enamel, the color sometimes has a slightly blue tone. Since enamel is semitranslucent, the color of dentin and any restorative dental material underneath the enamel strongly affects the appearance of a tooth. Enamel varies in thickness over the surface of the tooth and is often thickest at the cusp, up to 2.5 mm, and thinnest at its border, which is seen clinically as the cementoenamel junction (CEJ).
Enamel's primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. The large amount of minerals in enamel accounts not only for its strength but also for its brittleness. Dentin, which is less mineralized and less brittle, compensates for enamel and is necessary as a support. (More...)
July 31., 2006 - August 7.
The menstrual cycle is a recurring cycle of physiological changes in the females of some animal species that is associated with reproductive fertility. Only human beings and the great apes experience a true menstrual cycle. Most placental mammals experience estrus instead. The menstrual cycle is under the control of the reproductive hormone system and is necessary for reproduction. In women, menstrual cycles occur typically on a monthly basis between puberty and menopause.
During the menstrual cycle, the sexually mature female body builds up the lining of the uterus with gradually increasing amounts of estrogen, and when this hormone reaches a critical level, estradiol is produced, and shortly thereafterward there is the stimulation of the ovaries with Follicle Stimulating Hormone, and luteinizing hormone. Follicles begin developing, and within a few days one "matures" into an ovum or egg. The ovary then releases this egg, (or occasionally two, which might result in dizygotic, or non-identical, twins) at the time of ovulation. The lining of the uterus, the endometrium, peaks shortly there afterward in a synchronised fashion. After ovulation, this lining changes to prepare for potential conception and implantation of the fertilized egg to establish a pregnancy. The hormone progesterone rises after ovulation, and peaks shortly thereafter. (More...)
July 24., 2006 - July 31.
Tooth development is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. Although many diverse species have teeth, non-human tooth development is largely the same as in humans. For human teeth to have a healthy oral environment, enamel, dentin, cementum, and the periodontium must all develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth weeks in utero, and permanent teeth begin to form in the twentieth week in utero. If teeth do not start to develop at or near these times, they will not develop at all.
A significant amount of research has focused on determining the processes that initiate tooth development. It is widely accepted that there is a factor within the tissues of the first branchial arch that is necessary for the development of teeth. (More...)
July 17., 2006 - July 24.
Pneumonia is an illness of the lungs and respiratory system in which the alveoli (microscopic air-filled sacs of the lung responsible for absorbing oxygen from the atmosphere) become inflamed and flooded with fluid. Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites. Pneumonia may also occur from chemical or physical injury to the lungs, or indirectly due to another medical illness, such as lung cancer or alcohol abuse.
Typical symptoms associated with pneumonia include cough, chest pain, fever, and difficulty breathing. Diagnostic tools include x-rays and examination of the sputum. Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics.
Pneumonia is a common illness, occurs in all age groups, and is a leading cause of death among the elderly and people who are chronically ill. Vaccines to prevent certain types of pneumonia are available. The prognosis for an individual depends on the type of pneumonia, the appropriate treatment, any complications, and the person's underlying health. (More...)
July 10., 2006 - July 17.
Médecins Sans Frontières (ⓘ) is a secular humanitarian-aid non-governmental organisation best known for its projects in war-torn regions and developing countries facing endemic disease.
Médecins Sans Frontières was created in 1971 by a small group of French doctors, as an aftermath of the Biaffra secession. The organisation is known to much of the world by its French name or simply as MSF. In many countries (such as the United States), the English-translated name Doctors Without Borders is used instead. (More...)
July 4., 2006 - July 10.
Tuberculosis (commonly abbreviated as TB) is an infection caused by the bacterium Mycobacterium tuberculosis, which most commonly affects the lungs (pulmonary TB) but can also affect the central nervous system (meningitis), lymphatic system, circulatory system (Miliary tuberculosis), genitourinary system, bones and joints.
Tuberculosis is one of the most deadly and common major infectious diseases today. As of 2004, 14.6 million people have active TB disease with nine million new cases of the disease and nearly two million deaths, mostly in developing countries. However, developing countries are not the only places with tuberculosis. There is a rising number of people in the developed world who contract tuberculosis because they have compromised immune systems, typically as a result of immunosupressive drugs or HIV/AIDS. These people are at particular risk of tuberculosis infection and active tuberculosis disease. (More...)
June 28., 2006 - July 4.
Keratoconus (from Greek: kerato- horn, cornea; and konos cone), is a degenerative non-inflammatory disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape than its normal, gradual curve. Keratoconus can cause substantial distortion of vision, with multiple images, streaking and sensitivity to light all often reported by the patient. Though frequently thought of as a rare condition, keratoconus is the most common dystrophy of the cornea, affecting around one person in a thousand, and it seems to occur equally in all ethnic groups worldwide. It is typically diagnosed in the patient's adolescent years and attains its most severe state in the twenties and thirties. (More...)
June 20., 2006 — June 27.
Chagas disease (also called American trypanosomiasis) is a human tropical parasitic disease which occurs in the Americas, particularly in South America. Its pathogenic agent is a flagellate protozoan named Trypanosoma cruzi, which is transmitted to humans and other mammals mostly by hematophagous assassin bugs of the subfamily Triatominae (Family Reduviidae). Those insects are known by numerous common names varying by country, including benchuca, vinchuca, kissing bug, chipo, barbeiro, etcetera. The most common insect species belong to the genera Triatoma, Rhodnius, and Panstrongylus. Other forms of transmission are possible, though, such as ingestion of food contaminated with parasites, blood transfusion and fetal transmission.
Trypanosoma cruzi is a member of the same genus as the infectious agent of African sleeping sickness, but its clinical manifestations, geographical distribution, life cycle and insect vectors are quite different. (More...)
June 13., 2006 — June 20.
Because of this 'updating' function of the cerebellum, lesions within it are not so debilitating as to cause paralysis, but rather present as feedback deficits resulting in disorders in fine movement, equilibrium, posture, and motor learning. Initial observations by physiologists during the 18th century indicated that patients with cerebellar damage show problems with motor coordination and movement. Research into cerebellar function during the early to mid 19th century was done via lesion and ablation studies in animals. Research physiologists noted that such lesions led to animals with strange movements, awkward gait, and muscular weakness. These observations and studies led to the conclusion that the cerebellum was a motor control structure. However, modern research shows that the cerebellum has a broader role in a number of key cognitive functions, including attention and the processing of language, music, and other sensory temporal stimuli. (More...)
June 6., 2006 — June 13.
Helicobacter pylori is a bacterium that infects the mucus lining of the human stomach. Many peptic ulcers and some types of gastritis are caused by H. pylori infection, although most humans who are infected will never develop symptoms. This bacterium lives in the human stomach exclusively and is the only known organism that can thrive in that highly acidic environment. It is helix-shaped (hence the name helicobacter) and can literally screw itself into the stomach lining to colonize.
The bacterium was rediscovered in 1982 by two Australian scientists Robin Warren and Barry Marshall; they isolated the organisms from mucosal specimens from human stomachs and were the first to successfully culture them. In their original paper, Warren and Marshall contended that most stomach ulcers and gastritis were caused by colonization with this bacterium, not by stress or spicy food as had been assumed before. Read more...
May 24., 2006 — June 6.
Asthma is a disease of the human respiratory system where the airways narrow, often in response to a "trigger" such as exposure to an allergen, cold air, exercise, or emotional stress. This narrowing causes symptoms such as wheezing, shortness of breath, chest tightness, and coughing, which respond to bronchodilators. Between episodes, most patients feel fine.
The disorder is a chronic (reoccurring) inflammatory condition in which the airways develop increased responsiveness to various stimuli, characterized by bronchial hyper-responsiveness, inflammation, increased mucus production, and intermittent airway obstruction. The symptoms of asthma, which can range from mild to life threatening, can usually be controlled with a combination of drugs and lifestyle changes.
The word asthma is derived from the Greek aazein, meaning "sharp breath." The word first appears in Homer's Iliad. Hippocrates was the first to use it in reference to the medical condition. Hippocrates thought that the spasms associated with asthma were more likely to occur in tailors, anglers, and metalworkers. Six centuries later, Galen wrote much about asthma, noting that it was caused by partial or complete bronchial obstruction. Moses Maimonides, an influential medieval rabbi, philosopher, and physician, wrote a treatise on asthma, describing its prevention, diagnosis, and treatment.Read more...