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Shigella Dysenteriae
''Shigella dysenteriae'' is a species of the rod-shaped bacterial genus ''Shigella''. ''Shigella'' species can cause shigellosis ( bacillary dysentery). Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, nonmotile bacteria. ''S. dysenteriae'' has the ability to invade and replicate in various species of epithelial cells and enterocytes. Epidemiology Shigella infections may be contracted by a lack of monitoring of water and food quality, unsanitary cooking conditions and improper hygiene practices. ''S. dysenteriae'' spreads through contaminated water and food, causes minor dysentery because of its Shiga toxin, but other species may also be dysentery agents. ''S. dysenteriae'' releases an exotoxin that compromises the gut and central nervous system. If acting as an enterotoxin, diarrhea will occur. When acting as a neurotoxin, severe cases of shigellosis are developed, inducing comas and meningismus. Contamination is often caused by bacteria on unwashed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark-field Microscopy
Dark-field microscopy (also called dark-ground microscopy) describes microscopy methods, in both light and electron microscopy, which exclude the unscattered beam from the image. As a result, the field around the specimen (i.e., where there is no specimen to scatter the beam) is generally dark. In optical microscopes a darkfield condenser lens must be used, which directs a cone of light away from the objective lens. To maximize the scattered light-gathering power of the objective lens, oil immersion is used and the numerical aperture (NA) of the objective lens must be less than 1.0. Objective lenses with a higher NA can be used but only if they have an adjustable diaphragm, which reduces the NA. Often these objective lenses have a NA that is variable from 0.7 to 1.25. Light microscopy applications In optical microscopy, dark-field describes an illumination technique used to enhance the contrast in unstained samples. It works by illuminating the sample with light that will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxin
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nervous tissue.Olney 2002 The term can also be used to classify endogenous compounds, which, when abnormally contacted, can prove neurologically toxic. Though neurotoxins are often neurologically destructive, their ability to specifically target neural components is important in the study of nervous systems. Common examples of neurotoxins include lead, ethanol (drinking alcohol), glutamate,Choi 1987 nitric oxide, botulinum toxin (e.g. Botox), tetanus toxin,Simpson 1986 and tetrodotoxin. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Neurotoxins inhibit neuron control over ion concentrations across the cell membrane, or commu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XLD Agar
Xylose Lysine Deoxycholate agar (XLD agar) is a selective growth medium used in the isolation of '' Salmonella'' and ''Shigella'' species from clinical samples and from food. The agar was developed by Welton Taylor in 1965. It has a pH of approximately 7.4, leaving it with a bright pink or red appearance due to the indicator phenol red. Sugar fermentation lowers the pH and the phenol red indicator registers this by changing to yellow. Most gut bacteria, including ''Salmonella'', can ferment the sugar xylose to produce acid; ''Shigella'' colonies cannot do this and therefore remain red. After exhausting the xylose supply ''Salmonella'' colonies will decarboxylate lysine, increasing the pH once again to alkaline and mimicking the red ''Shigella'' colonies. Salmonellae metabolise thiosulfate to produce hydrogen sulfide, which leads to the formation of colonies with black centers and allows them to be differentiated from the similarly coloured ''Shigella'' colonies. Other Enteroba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kidney Failure
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as either acute kidney failure, which develops rapidly and may resolve; and chronic kidney failure, which develops slowly and can often be irreversible. Symptoms may include leg swelling, feeling tired, vomiting, loss of appetite, and confusion. Complications of acute and chronic failure include uremia, high blood potassium, and volume overload. Complications of chronic failure also include heart disease, high blood pressure, and anemia. Causes of acute kidney failure include low blood pressure, blockage of the urinary tract, certain medications, muscle breakdown, and hemolytic uremic syndrome. Causes of chronic kidney failure include diabetes, high blood pressure, nephrotic syndrome, and polycystic kidney disease. Diagnosis of acute f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombocytopenia
Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients and a third of surgical patients. A normal human platelet count ranges from 150,000 to 450,000 platelets/microliter (μl) of blood. Values outside this range do not necessarily indicate disease. One common definition of thrombocytopenia requiring emergency treatment is a platelet count below 50,000/μl. Thrombocytopenia can be contrasted with the conditions associated with an abnormally ''high'' level of platelets in the blood - thrombocythemia (when the cause is unknown), and thrombocytosis (when the cause is known). Signs and symptoms Thrombocytopenia usually has no symptoms and is picked up on a routine complete blood count. Some individuals with thrombocytopenia may experience external bleeding, such as nosebleeds or bleeding gum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, the symptoms are often vague, such as tiredness, weakness, shortness of breath, headaches, and a reduced ability to exercise. When anemia is acute, symptoms may include confusion, feeling like one is going to pass out, loss of consciousness, and increased thirst. Anemia must be significant before a person becomes noticeably pale. Symptoms of anemia depend on how quickly hemoglobin decreases. Additional symptoms may occur depending on the underlying cause. Preoperative anemia can increase the risk of needing a blood transfusion following surgery. Anemia can be temporary or long term and can range from mild to severe. Anemia can be caused by blood loss, decreased red blood cell production, and increased red blood cell breakdown. Causes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Nervous System
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of bilaterally symmetric and triploblastic animals—that is, all multicellular animals except sponges and diploblasts. It is a structure composed of nervous tissue positioned along the rostral (nose end) to caudal (tail end) axis of the body and may have an enlarged section at the rostral end which is a brain. Only arthropods, cephalopods and vertebrates have a true brain (precursor structures exist in onychophorans, gastropods and lancelets). The rest of this article exclusively discusses the vertebrate central nervous system, which is radically distinct from all other animals. Overview In vertebrates, the brain and spinal cord are both enclosed in the meninges. The meninges provide a barrier to chemicals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactive Arthritis
Reactive arthritis, also known as Reiter's syndrome, is a form of inflammatory arthritis that develops in response to an infection in another part of the body (cross-reactivity). Coming into contact with bacteria and developing an infection can trigger the disease. By the time the patient presents with symptoms, often the "trigger" infection has been cured or is in remission in chronic cases, thus making determination of the initial cause difficult. The arthritis often is coupled with other characteristic symptoms; this has been called Reiter's syndrome, Reiter's disease or Reiter's arthritis. The term "reactive arthritis" is increasingly used as a substitute for this designation because of Hans Reiter's war crimes with the Nazi Party. The manifestations of reactive arthritis include the following triad of symptoms: an inflammatory arthritis of large joints, inflammation of the eyes in the form of conjunctivitis or uveitis, and urethritis in men or cervicitis in women. Arthriti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rectal Tenesmus
Rectal tenesmus is a feeling of incomplete defecation. It is the sensation of inability or difficulty to empty the bowel at defecation, even if the bowel contents have already been evacuated. Tenesmus indicates the feeling of a residue, and is not always correlated with the actual presence of residual fecal matter in the rectum. It is frequently painful and may be accompanied by involuntary straining and other gastrointestinal symptoms. Tenesmus has both a nociceptive and a neuropathic component. Often, rectal tenesmus is simply called tenesmus. The term rectal tenesmus is a retronym to distinguish defecation-related tenesmus from vesical tenesmus. Vesical tenesmus is a similar condition, experienced as a feeling of incomplete voiding despite the bladder being empty. Tenesmus is a closely related topic to obstructed defecation. The term is from la, tēnesmus, from Greek , from to stretch, strain. Considerations Tenesmus is characterized by a sensation of needing to pass st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rectal Prolapse
A rectal prolapse occurs when walls of the rectum have prolapsed to such a degree that they protrude out of the anus and are visible outside the body. However, most researchers agree that there are 3 to 5 different types of rectal prolapse, depending on whether the prolapsed section is visible externally, and whether the full or only partial thickness of the rectal wall is involved. Rectal prolapse may occur without any symptoms, but depending upon the nature of the prolapse there may be mucous discharge (mucus coming from the anus), rectal bleeding, degrees of fecal incontinence and obstructed defecation symptoms. Rectal prolapse is generally more common in elderly women, although it may occur at any age and in either sex. It is very rarely life-threatening, but the symptoms can be debilitating if left untreated. Most external prolapse cases can be treated successfully, often with a surgical procedure. Internal prolapses are traditionally harder to treat and surgery may not be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malnutrition
Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues and form. Malnutrition is not receiving the correct amount of nutrition. Malnutrition is increasing in children under the age of five due to providers who cannot afford or do not have access to adequate nutrition. Malnutrition is a category of diseases that includes undernutrition and overnutrition. Undernutrition is a lack of nutrients, which can result in stunted growth, wasting, and underweight. A surplus of nutrients causes overnutrition, which can result in obesity. In some developing countries, overnutrition in the form of obesity is beginning to appear within the same communities as undernutrition. Most clinical studies use the term 'malnutrition' to refer to undernutrition. However, the use of 'malnutrition' instead of 'unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
