| PFU | plaque-forming unit; pock-forming unit |
|---|---|
| PI | first meiotic prophase; isoelectric point; pacing impulse; package insert; pancreatic insufficiency;... |
| PN | papillary necrosis; parenteral nutrition; penicillin; perceived noise; percussion note; periarteriti... |
| PrA-HPA | protein A hemolytic plaque assay |
| PRNT | plaque reduction neutralization test |
| neuritic plaque | <cell biology> Abnormal cluster of dead and dying nerve cells, other brain cells and protein. Neuritic plaques are one of the characteristic structural abnormalities found in the brains of alzheimer patients. Upon autopsy, the presence of neuritic plaques andneurofibrillary tangles is used to positively diagnose Alzheimer's disease. (22 May 1997) |
|---|---|
| dental plaque | <dentistry> A soft, thin film of food debris, mucin and dead epithelial cells deposited on the teeth, providing the medium for the growth of various bacteria. The main inorganic components are calcium and phosphorus with small amounts of magnesium, potassium and sodium, the organic matrix consists of polysaccharides, proteins, carbohydrates, lipids and other components. Plaque plays an important aetiological role in the development of dental caries and periodontal and gingival diseases and provides the base for the development of materia alba, calcified plaque forms dental calculus. (19 Mar 1998) |
| dental plaque index | An index which scores the degree of dental plaque accumulation. (12 Dec 1998) |
| fibrous plaque | Thickened area of arterial intima with accumulation of smooth muscle cells and fibrous tissue (collagen etc.) produced by the fat laden smooth muscle cells. Below the thickening may be free extracellular lipid and debris that, if much necrosis is also present, is referred to as an atheroma. (18 Nov 1997) |
| blood patch, epidural | The injection of autologous blood into the epidural space either as a prophylactic treatment immediately following an epidural puncture or for treatment of headache as a result of an epidural puncture. (12 Dec 1998) |
| butterfly patch | Origin: Perh. From the colour of a yellow species. AS. Buter-flege, buttor-fleoge; cf. G. Butterfliege, D. Botervlieg. See Butter, and Fly. <zoology> A general name for the numerous species of diurnal Lepidoptera. See: Illust. Under Aphrodite] Asclepias butterfly. See Asclepias. Butterfly fish, a kind of double clack valve, consisting of two semicircular clappers or wings hinged to a cross rib in the pump bucket. When open it somewhat resembles a butterfly in shape. Source: Websters Dictionary (01 Mar 1998) |
| patch clamp | <physiology> A specialised and powerful variant of voltage clamping, in which a patch electrode of relatively large tip diameter (5m) is pressed tightly against the plasma membrane of a cell, forming an electrically tight, gigohm seal. The current flowing through individual ion channels can then be measured. Different variants on this technique allow different surfaces of the plasma membrane to be exposed to the bathing medium: the contact just described is a cell attached patch. If the electrode is pulled away, leaving just a small disc of plasma membrane occluding the tip of the electrode, it is called an inside out patch. If suction is applied to a cell attached patch, bursting the plasma membrane under the electrode, a whole cell patch (similar to an intracellular recording) is formed. If the electrode is withdrawn from the whole cell patch, the membrane fragments adhering to the electrode reform a seal across the tip, forming an outside out patch. (15 Mar 2000) |
| patch clamping | <physiology> A specialised and powerful variant of voltage clamping, in which a patch electrode of relatively large tip diameter (5m) is pressed tightly against the plasma membrane of a cell, forming an electrically tight, gigohm seal. The current flowing through individual ion channels can then be measured. Different variants on this technique allow different surfaces of the plasma membrane to be exposed to the bathing medium: the contact just described is a cell attached patch. If the electrode is pulled away, leaving just a small disc of plasma membrane occluding the tip of the electrode, it is called an inside out patch. If suction is applied to a cell attached patch, bursting the plasma membrane under the electrode, a whole cell patch (similar to an intracellular recording) is formed. If the electrode is withdrawn from the whole cell patch, the membrane fragments adhering to the electrode reform a seal across the tip, forming an outside out patch. (15 Mar 2000) |
| patch-clamp techniques | An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used. (15 Mar 2000) |
| patch test | A test of skin sensitiveness: a small piece of paper, tape, or a cup, wet with CO non-irritating diluted test fluid, is applied to skin of the upper back or upper outer arm and after 48 hours the area previously covered is compared with the uncovered surface; an erythematous reaction with vesicles occurs if the substance causes contact allergy. See: photo-patch test. (05 Mar 2000) |
| patch tests | Skin tests in which the sensitiser is applied to a patch of cotton cloth or gauze held in place for approximately 48-72 hours. It is used for the elicitation of a contact hypersensitivity reaction. (12 Dec 1998) |
| peyer's patch | One of the lymphatic nodule aggregates existing in the intestines. (09 Oct 1997) |
| photo-patch test | A test of contact photosensitization: after application of a patch with the suspected sensitiser for 48 hours to two sites, if there is no reaction one area is exposed to a weak erythema dose of sunlight or ultraviolet light; if positive, a more severe reaction with vesiculation develops at the exposed patch area than the nonexposed skin patch site. (05 Mar 2000) |
| moth patch | <dermatology> Melasma cholasma hepaticum a term formerly used to refer to circumscribed facial hyperpigmentation resembling melasma that may occur as a cutaneous manifestation of chronic liver disease. Origin: Gr. Chloazein = to be green (18 Nov 1997) |
| whole cell patch | <physiology> A variant of patch clamp technique, in which the patch electrode seals against the cell, with direct communication between the interior of the electrode and the cytoplasm. (18 Nov 1997) |