| pleasure-pain principle | The psychoanalytic concept that man instinctively seeks to avoid pain and discomfort and strives for gratification and pleasure. (12 Dec 1998) |
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| pleasure principle | A psychoanalytic concept that, in a human's psychic functioning, he/she tends to seek pleasure and avoid pain; a term borrowed by experimental psychology to denote the same tendency of an animal in a learning situation. Synonym: pleasure principle. (05 Mar 2000) |
| multi-colony-stimulating factor | <cytokine> Product of mitogen activated T-cells: colony-stimulating factor for bone marrow stem cells and mast cells. A multilineage cell growth factor secreted by lymphocytes, epithelial cells, and astrocytes which stimulates clonal proliferation and differentiation of various types of blood and tissue cells. It is considered one of the haematopoietic colony-stimulating factors. Synonym: multi-CSF Acronym: IL-3 (12 Dec 1998) |
| multipotential colony-stimulating factor | <cytokine> Product of mitogen activated T-cells: colony-stimulating factor for bone marrow stem cells and mast cells. A multilineage cell growth factor secreted by lymphocytes, epithelial cells, and astrocytes which stimulates clonal proliferation and differentiation of various types of blood and tissue cells. It is considered one of the haematopoietic colony-stimulating factors. Synonym: multi-CSF Acronym: IL-3 (12 Dec 1998) |
| consistency principle | In psychology, the desire of the human being to be consistent, especially in his attitudes and beliefs; theories of attitude formation and change based on the consistency principle include balance theory, which suggests that the individual seeks to avoid incongruity in his various attitudes. See: cognitive dissonance theory. (05 Mar 2000) |
| haematinic principle | The principle previously thought to be produced by the action of Castle's intrinsic factor upon an extrinsic factor in food, now recognised as vitamin B12. (05 Mar 2000) |
| principle | 1. Beginning; commencement. "Doubting sad end of principle unsound." (Spenser) 2. A source, or origin; that from which anything proceeds; fundamental substance or energy; primordial substance; ultimate element, or cause. "The soul of man is an active principle." (Tillotson) 3. An original faculty or endowment. "Nature in your principles hath set [benignity]" (Chaucer) "Those active principles whose direct and ultimate object is the communication either of enjoyment or suffering." (Stewart) 4. A fundamental truth; a comprehensive law or doctrine, from which others are derived, or on which others are founded; a general truth; an elementary proposition; a maxim; an axiom; a postulate. "Therefore, leaving the principles of the doctrine of Christ, let us go on unto perfection." (Heb. Vi. 1) "A good principle, not rightly understood, may prove as hurtful as a bad." (Milton) 5. A settled rule of action; a governing law of conduct; an opinion or belief which exercises a directing influence on the life and behavior; a rule (usually, a right rule) of conduct consistently directing one's actions; as, a person of no principle. "All kinds of dishonesty destroy our pretenses to an honest principle of mind." (Law) 6. <chemistry> Any original inherent constituent which characterises a substance, or gives it its essential properties, and which can usually be separated by analysis; applied especially to drugs, plant extracts, etc. "Cathartine is the bitter, purgative principle of senna." (Gregory) Bitter principle, Principle of contradiction, etc. See Bitter, Contradiction, etc. Origin: F. Principe, L. Principium beginning, foundation, fr. Princeps, -cipis. See Prince. Source: Websters Dictionary (01 Mar 1998) |
| principle of inertia | In psychoanalysis, the impulse to redramatise or reenact earlier emotional experiences or situations. Synonym: principle of inertia. (05 Mar 2000) |
| proximate principle | In chemistry, an organic compound that may exist already formed as a part of some other more complex substance (e.g., various sugars, starches, and albumins). Synonym: organic principle. (05 Mar 2000) |
| hormone, thyroid stimulating | A hormone produced by the pituitary gland (at the base of the brain) that promotes the growth of the thyroid gland (in the neck) and stimulates it to produce its thyroid hormones. Normally, the rate of thyroid hormone production is controlled by the pituitary. When there are insufficient thyroid hormones in the body for normal functioning of the cells, the pituitary releases tsh. Tsh in turn stimulates the thyroid gland to produce more thyroid hormones. In contrast, when there is excessive amount of thyroid hormones, the pituitary gland stops producing tsh. The tsh level then falls and thyroid hormone production is reduced. This mechanism maintains a relatively constant level of thyroid hormones circulating in the blood. This phenomenon is analogous to a thermostat used for temperature regulation in a room: when the temperature rises, the thermostat shuts the heater off and the room temperature falls back to normal. High levels of thyroid hormones cause the tsh level to fall, resulting in no further stimulation of the thyroid gland. In hyperthyroidism, there are continuously elevated levels of the thyroid hormones. Tsh is also known as thyrotropin. (12 Dec 1998) |
| Huygens' principle | Used in ultrasound technology; the principle that any wave phenomenon can be analyzed as the sum of many simple sources properly chosen with regard to phase and amplitude. (05 Mar 2000) |
| natural killer cell stimulating factor | <cytokine> A 75 kD heterodimeric cytokine composed of disulfide-bonded 40 kD and 35 kD subunits that was originally identified by its ability to induce cytotoxic effector cells in synergy with less than optimal concentrations of interleukin-2. It is released by macrophages in response to infection and promotes the activation of cell-mediated immunity. Specifically, IL-12 triggers the maturation of Thl CD4 cells, specific cytotoxic T-lymphocyte responses and an increase in the activity of NK cells and consequently, it is the initiator of cell-mediated immunity. It enhances the lytic activity of NK cells, induces interferon production, stimulates the proliferation of activated T-cells and NK cells. Is secreted by human B lymphoblastoid cells (NC 37). May play a role in controlling immunoglobulin isotype selection as it also inhibits IgE synthesis (even in the presence of anti-IFN monoclonal antibody) and as a growth factor for activated CD4+ and CD8+ T-cells independently of interleukin-2, and for CD56+ NK cells but not resting peripheral blood mononuclear cells or resting or activated tonsillar B-cells. It is likely that interleukin 12 has a major role in protective immunity against viruses and is under study as an immunotherapy in HIV infection. Formerly referred to as cytotoxic lymphocyte maturation factor. Acronym: IL-12 (12 Dec 1998) |
| Stewart-Hamilton principle | Used to determine blood flow from the concentration of dye or temperature dilution. (05 Mar 2000) |
| nirvana principle | In psychoanalysis, the principle that expresses the tendency toward the death instinct. (05 Mar 2000) |
| immunoglobulins, thyroid-stimulating | Autoantibodies that bind to the thyroid-stimulating hormone (tsh) receptor (receptors, thyrotropin) on thyroid epithelial cells. The autoantibodies mimic tsh causing an unregulated production of thyroid hormones characteristic of graves' disease. (12 Dec 1998) |