| Posadas disease | <chest medicine, microbiology> A fungal infection caused by the fungus Coccidioides immitis. Exists in two forms: primary disease, which is a self-limited respiratory infection (requires no treatment) and a progressive form (diffuse and granulomatous), that can involve almost any part of the body. Approximately 60% of infections cause no symptoms and are identified only by skin testing. Immunocompromised patients (AIDS) are at greatest risk for disseminated disease. Symptoms include cough, anorexia, fever, weight loss and joint pains. Complications include pleural effusion and dissemination. There is a poor prognosis for disseminated disease. Treatment includes amphotericin B for lung infection. Itraconazole and fluconazole are also useful agents. (27 Sep 1997) |
|---|---|
| Posadas, Alejandro | <person> Argentinian parasitologist, 1870-1902. See: Posadas disease. (05 Mar 2000) |
| position | 1. The state of being posited, or placed; the manner in which anything is placed; attitude; condition; as, a firm, an inclined, or an upright position. "We have different prospects of the same thing, according to our different positions to it." (Locke) 2. The spot where a person or thing is placed or takes a place; site; place; station; situation; as, the position of man in creation; the fleet changed its position. 3. Hence: The ground which any one takes in an argument or controversy; the point of view from which any one proceeds to a discussion; also, a principle laid down as the basis of reasoning; a proposition; a thesis; as, to define one's position; to appear in a false position. "Let not the proof of any position depend on the positions that follow, but always on those which go before." (I. Watts) 4. Relative place or standing; social or official rank; as, a person of position; hence, office; post; as, to lose one's position. 5. <mathematics> A method of solving a problem by one or two suppositions; called also the rule of trial and error. <astronomy> Angle of position, the angle which any line (as that joining two stars) makes with another fixed line, specifically with a circle of declination. <mathematics> Double position, a position taken up by an army or a large detachment of troops for the purpose of checking or observing an opposing force. Synonym: Situation, station, place, condition, attitude, posture, proposition, assertion, thesis. Origin: F. Position, L. Positio, fr. Ponere, positum, to put, place; prob. For posino, fr. An old preposition used only in comp. (akin to Gr) + sinere to leave, let, permit, place. See Site, and cf. Composite, Compound, Depone, Deposit, Expound, Impostor, Opposite, Propound, Pose, Posit, Post. Source: Websters Dictionary (01 Mar 1998) |
| position agnosia | The failure to recognise the posture of an extremity. (05 Mar 2000) |
| position effect | A change in the phenotypic expression of one or more genes due to a change in its physical location with respect to other genes; may result from change in chromosome structure or from crossing-over. (05 Mar 2000) |
| position sense | The ability to recognise the position in which a limb is passively placed, with the eyes closed. Synonym: position sense. (05 Mar 2000) |
| positional | Of or pertaining to position. "Ascribing unto plants positional operations." (Sir T. Browne) Source: Websters Dictionary (01 Mar 1998) |
| positional cloning | Cloning a gene based simply on knowing its position in the genome without any idea of the function of that gene. Because this is the reverse of how things have been traditionally done, it has also been called reverse genetics. (12 Dec 1998) |
| positional information | The instructions that are interpreted by cells to determine their differentiation in respect of their position relative to other parts of the organism, for example digit formation in the limb bud of vertebrates. (18 Nov 1997) |
| positional nystagmus | Nystagmus occurring only when the head is in a particular position. (05 Mar 2000) |
| positional probability | <chemistry> A type of probability that depends on the number of arrangements in space that yield a particular state. (09 Jan 1998) |
| positional vertigo of Barany | Brief attacks of paroxysmal vertigo and nystagmus that occur solely with certain head movements or positions, e.g., with neck extension; due to labyrinthine dysfunction. Synonym: positional vertigo of Barany, postural vertigo. (05 Mar 2000) |
| positioner | A resilient elastoplastic or rubber removable appliance fitting over the occlusal surface of the teeth, to obtain limited tooth movement and/or stabilization, usually used at the end of orthodontic treatment. (05 Mar 2000) |
| positive | Having a value greater than zero, indicating existence or presence of a condition, organism, etc. As chromatin positive or Wassermann positive, characterised by affirmation or cooperation. Origin: L. Positivus (18 Nov 1997) |
| positive accommodation | The increased refractivity of the eye that occurs when shifting from the distance to a near object. (05 Mar 2000) |