| PAT | Bouts of rapid, regular heart beating originating in the atrium (upper chamber of the heart). Due to abnormalities in the av node relay station that lead to rapid firing of electrical impulses from the atrium which bypass the av node under certain conditions. These conditions include alcohol excess, stress, caffeine, overactive thyroid or excessive thyroid hormone intake, and certain drugs. Pat is an example of an arrhythmia where the abnormality is in the electrical system of the heart, while the heart muscle and valves may be normal. (12 Dec 1998) |
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| pat1 protein kinase | <enzyme> Negatively regulated by mei3+ gene product Registry number: EC 2.7.1.- Synonym: ran1 protein (26 Jun 1999) |
| patagium | 1. <anatomy> In bats, an expansion of the integument uniting the fore limb with the body and extending between the elongated fingers to form the wing; in birds, the similar fold of integument uniting the fore limb with the body. 2. <zoology> One of a pair of small vesicular organs situated at the bases of the anterior wings of lepidopterous insects. Origin: L, an edge or border. Source: Websters Dictionary (01 Mar 1998) |
| patas | <zoology> A West African long-tailed monkey (Cercopithecus ruber); the red monkey. Source: Websters Dictionary (01 Mar 1998) |
| Patau's syndrome | <embryology, paediatrics, syndrome> A congenital disorder caused by a person having an extra (three copies of) chromosome 13, this disorder causes severe eye, brain and heart defects and is also characterised by a cleft lip and cleft palate. See: trisomy 13 syndrome (09 Oct 1997) |
| Patau, Klaus | <person> A 20th century U.S. Cytogeneticist. See: Patau's syndrome. (05 Mar 2000) |
| patavinity | The use of local or provincial words, as in the peculiar style or diction of Livy, the Roman historian; so called from Patavium, now Padua, the place of Livy's nativity. Origin: L. Patavinitas, fr. Patavium: cf. F. Patavinite. 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 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) |
| 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) |
| patching | <physiology> Passive process in which integral membrane components become clustered following cross linking by an external or internal polyvalent ligand. See: capping. (18 Nov 1997) |
| patchoulol synthase | <enzyme> From pogostemon cablin; has the ability to transform farnesyl pyrophosphate to cyclic olefins (alpha- and beta- patchoulene, alpha-bulnesene, and alpha-guiaene); a sesquiterpene cyclase Registry number: EC 5.- (26 Jun 1999) |
| patchouly | 1. <botany> A mintlike plant (Pogostemon Patchouli) of the East Indies, yielding an essential oil from which a highly valued perfume is made. 2. The perfume made from this plant. <chemistry> Patchouly camphor, a substance homologous with and resembling borneol, found in patchouly oil. Origin: CF. F. Patchouli; prob. Of East Indian origin. Source: Websters Dictionary (01 Mar 1998) |