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Band Keratopathy
Band keratopathy is a corneal disease derived from the appearance of calcium on the central cornea. This is an example of metastatic calcification, which by definition, occurs in the presence of hypercalcemia. Signs and symptoms Signs and symptoms of band keratopathy include eye pain and decreased visual acuity. Causes Band keratopathy has several causes. These causes include uveitis, interstitial keratitis, superficial keratitis, phthisis, sarcoidosis, trauma, intraocular silicone oil, systemic diseases ( high levels of calcium in the blood, vitamin D intoxication, Fanconi's Syndrome, low levels of phosphorus in the blood, gout, milk-alkali syndrome, myotonic dystrophy, and chronic mercury exposure). Pathology Band keratopathy is seen when there is calcification of the epithelial basement membrane, Bowman's layer, and the anterior stroma with destruction of Bowman's layer. The calcium salts are intracellular when the process is due to alteration of systemic calcium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corneal Disease
The cornea is the transparent front part of the eyeball which covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. The cornea can be reshaped by surgical procedures such as LASIK. While the cornea contributes most of the eye's focusing power, its focus is fixed. Accommodation (the refocusing of light to better view near objects) is accomplished by changing the geometry of the lens. Medical terms related to the cornea often start with the prefix "'' kerat-''" from the Greek word κέρας, ''horn''. Structure The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the healthy cornea does not have or need blood vessels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypervitaminosis D
Vitamin D toxicity, or hypervitaminosis D, is the toxic state of an excess of vitamin D. The normal range for blood concentration of 25-hydroxyvitamin D in adults is 20 to 50 nanograms per milliliter (ng/mL). Blood levels necessary to cause adverse effects in adults are thought to be greater than about 150 ng/mL, leading the Endocrine Society to suggest an upper limit for safety of 100 ng/mL. Signs and symptoms An excess of vitamin D causes abnormally high blood concentrations of calcium, which can cause overcalcification of soft tissues, including arteries and kidneys. Symptoms appear several months after excessive doses of vitamin D are administered. A mutation of the CYP24A1 gene can lead to a reduction in the degradation of vitamin D and thus to vitamin toxicity without high oral intake (see ). Symptoms of vitamin D toxicity may include the following: * Dehydration * Vomiting * Diarrhea * Decreased appetite * Irritability * Constipation * Fatigue * Muscle we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EDTA
Ethylenediaminetetraacetic acid (EDTA), also called EDTA acid, is an aminopolycarboxylic acid with the formula . This white, slightly water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-soluble complexes even at neutral pH. It is thus used to dissolve Fe- and Ca-containing scale as well as to deliver iron ions under conditions where its oxides are insoluble. EDTA is available as several salts, notably disodium EDTA, sodium calcium edetate, and tetrasodium EDTA, but these all function similarly. Uses EDTA is widely used in industry. It also has applications in food preservation, medicine, cosmetics, water softening, in laboratories, and other fields. Industrial EDTA is mainly used to sequester (bind or confine) metal ions in aqueous solution. In the textile industry, it prevents metal ion impurities from modifying colours of dyed products. In the pulp and paper industry, EDTA inhibits the ability of metal ions, especiall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slit Lamp
In ophthalmology and optometry, a slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. It is used in conjunction with a biomicroscope. The lamp facilitates an examination of the anterior segment and posterior segment of the human eye, which includes the eyelid, sclera, conjunctiva, iris (anatomy), iris, natural crystalline lens, and cornea. The binocular slit-lamp examination provides a stereoscopic magnified view of the eye structures in detail, enabling anatomical diagnoses to be made for a variety of eye conditions. A second, hand-held lens is used to examine the retina. History Two conflicting trends emerged in the development of the slit lamp. One trend originated from clinical research and aimed to apply the increasingly complex and advanced technology of the time. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowman's Layer
The Bowman's layer (Bowman's membrane, anterior limiting lamina, anterior elastic lamina) is a smooth, acellular, nonregenerating layer, located between the superficial epithelium and the stroma in the cornea of the eye. It is composed of strong, randomly oriented collagen fibrils in which the smooth anterior surface faces the epithelial basement membrane and the posterior surface merges with the collagen lamellae of the corneal stroma proper. In adult humans, Bowman's layer is 8-12 μm thick. With ageing, this layer becomes thinner. The function of the Bowman's layer remains unclear and it appears to have no critical function in corneal physiology. Recently, it is postulated that the layer may act as a physical barrier to protect the subepithelial nerve plexus and thereby hastens epithelial innervation and sensory recovery. Moreover, it may also serve as a barrier that prevents direct traumatic contact with the corneal stroma and hence it is highly involved in stromal wound he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basement Membrane
The basement membrane, also known as base membrane, is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between epithelial tissues including mesothelium and endothelium, and the underlying connective tissue. Structure As seen with the electron microscope, the basement membrane is composed of two layers, the basal lamina and the reticular lamina. The underlying connective tissue attaches to the basal lamina with collagen VII anchoring fibrils and fibrillin microfibrils. The basal lamina layer can further be subdivided into two layers based on their visual appearance in electron microscopy. The lighter-colored layer closer to the epithelium is called the lamina lucida, while the denser-colored layer closer to the connective tissue is called the lamina densa. The electron-dense lamina densa layer is about 30–70 nanometers thick and consists of an und ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelia
Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of many internal organs, the corresponding inner surfaces of body cavities, and the inner surfaces of blood vessels. Epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. These tissues also lack blood or lymph supply. The tissue is supplied by nerves. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either simple squamous, simple columnar, or simple cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myotonic Dystrophy
Myotonic dystrophy (DM) is a type of muscular dystrophy, a group of genetic disorders that cause progressive muscle loss and weakness. In DM, muscles are often myotonia, unable to relax after contraction. Other manifestations may include cataracts, intellectual disability and arrhythmia, heart conduction problems. In men, there may be early balding and infertility. While myotonic dystrophy can occur at any age, onset is typically in the 20s and 30s. Myotonic dystrophy is caused by a genetic mutation in one of two genes. Mutation of the ''Myotonin-protein kinase, DMPK'' gene causes myotonic dystrophy type 1 (DM1). Mutation of ''CNBP'' gene causes type 2 (DM2). DM is typically heredity, inherited, following an autosomal dominant inheritance pattern, and it generally anticipation (genetics), worsens with each generation. A type of DM1 may be apparent at birth. DM2 is generally milder. Diagnosis is confirmed by genetic testing. There is no cure. Treatments may include braces or wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milk-alkali Syndrome
Milk-alkali syndrome (MAS), also referred to as calcium-alkali syndrome, is the third most common cause of elevated blood calcium levels ( hypercalcemia). Milk-alkali syndrome is characterized by hypercalcemia, metabolic alkalosis, and acute kidney injury. Milk-alkali syndrome can be caused by the excessive intake of calcium and absorbable alkali. Sources of calcium and alkali include dietary supplements taken for the prevention of osteoporosis or hyperparathyroidism and antacids taken for peptic ulcer disease. Common acute symptoms of milk-alkali syndrome include nausea and vomiting, dry mouth, confusion, lethargy, and distaste for milk. If left untreated, milk-alkali syndrome may lead to kidney failure or even death. Signs and symptoms The signs and symptoms of milk-alkali syndrome can develop after only a few days and up to several months following the initial ingestion of absorbable calcium and alkali. However, the severity of signs and symptoms of milk-alkali syndrome i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gout
Gout ( ) is a form of inflammatory arthritis characterized by recurrent attacks of pain in a red, tender, hot, and Joint effusion, swollen joint, caused by the deposition of needle-like crystals of uric acid known as monosodium urate crystals. Pain typically comes on rapidly, reaching maximal intensity in less than 12 hours. The Metatarsophalangeal joint, joint at the base of the Hallux, big toe is affected (''Podagra'') in about half of cases. It may also result in Tophus, tophi, kidney stones, or Urate nephropathy, kidney damage. Gout is due to persistently elevated levels of uric acid (urate) in the blood (hyperuricemia). This occurs from a combination of diet, other health problems, and genetic factors. At high levels, uric acid crystallizes and the crystals deposit in joints, tendons, and surrounding tissues, resulting in an attack of gout. Gout occurs more commonly in those who regularly drink beer or sugar-sweetened beverages; eat foods that are high in purines such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypophosphatemia
Hypophosphatemia is an electrolyte disorder in which there is a low level of phosphate in the blood. Symptoms may include weakness, trouble breathing, and loss of appetite. Complications may include seizures, coma, rhabdomyolysis, or softening of the bones. Nutritional phosphate deficiency is exceedingly rare as phosphate is abundant in most types of foods and is readily passively absorbed from the gastrointestinal tract; hypophosphatemia is thus typically a result of diseases or an adverse effect of medical treatments. Causes include alcohol use disorder, refeeding in those with malnutrition, recovery from diabetic ketoacidosis, burns, hyperventilation, and certain medications. It may also occur in the setting of hyperparathyroidism, hypothyroidism, and Cushing syndrome. It is diagnosed based on a blood phosphate concentration of less than 0.81 mmol/L (2.5 mg/dL). When levels are below 0.32 mmol/L (1.0 mg/dL) it is deemed to be severe. Treatment depends on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fanconi's Syndrome
Fanconi syndrome or Fanconi's syndrome (, ) is a syndrome of inadequate reabsorption in the proximal renal tubules of the kidney. The syndrome can be caused by various underlying congenital or acquired diseases, by toxicity (for example, from toxic heavy metals), or by adverse drug reactions. It results in various small molecules of metabolism being passed into the urine instead of being reabsorbed from the tubular fluid (for example, glucose, amino acids, uric acid, phosphate, and bicarbonate). Fanconi syndrome affects the proximal tubules, namely, the proximal convoluted tubule (PCT), which is the first part of the tubule to process fluid after it is filtered through the glomerulus, and the proximal straight tubule (pars recta), which leads to the descending limb of loop of Henle. Different forms of Fanconi syndrome can affect different functions of the proximal tubule, and result in different complications. The loss of bicarbonate results in type 2 or proximal renal tubular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
