| PLL | peripheral light loss; phase-locked loop; poly-L-lysine; pressure length loop; posterior longitudina... |
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| POMP | phase-offset multiplanar [pulse sequence in magnetic resonance imaging]; principal outer material pr... |
| PRC | packed red cells; peer review committee; phase response curve; plasma renin concentration; professio... |
| PSD | particle size distribution; peptone, starch, and dextrose; periodic synchronous discharge; phase-sen... |
| PTC | papillary thyroid carcinoma; percutaneous transhepatic cholangiography; phase transfer catalyst; phe... |
| clinical trials, phase I | Studies performed to evaluate the safety of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques in healthy subjects and to determine the safe dosage range (if appropriate). These tests also are used to determine pharmacologic and pharmacokinetic properties (toxicity, metabolism, absorption, elimination, and preferred route of administration). They involve a small number of persons and usually last about 1 year. This concept includes phase I studies conducted both in the u.s. And in other countries. (12 Dec 1998) |
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| clinical trials, phase II | Studies that are usually controlled to assess the effectiveness and dosage (if appropriate) of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques. These studies are performed on several hundred volunteers, including a limited number of patients with the target disease or disorder, and last about two years. This concept includes phase II studies conducted in both the u.s. And in other countries. (12 Dec 1998) |
| clinical trials, phase III | Comparative studies to verify the effectiveness of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques determined in phase II studies. During these trials, patients are monitored closely by physicians to identify any adverse reactions from long-term use. These studies are performed on groups of patients large enough to identify clinically significant responses and usually last about three years. This concept includes phase III studies conducted in both the u.s. And in other countries. (12 Dec 1998) |
| clinical trials, phase IV | Planned post-marketing studies of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques that have been approved for general sale. These studies are often conducted to obtain additional data about the safety and efficacy of a product. This concept includes phase IV studies conducted in both the u.s. And in other countries. (12 Dec 1998) |
| M phase | Mitotic phase of cell cycle of eukaryotic cells, as distinct from the remainder, which is known as interphase (and that can be further subdivided as G1, s and G2). Beginning of M is signalled by separation of centrioles, where present and by the condensation of chromatin into chromosomes. M phase ends with the establishment of nuclear membranes around the two daughter nuclei, normally followed immediately by cell division (cytokinesis). (18 Nov 1997) |
| M phase promoting factor | Protein whose levels rise rapidly just before and fall away just after, mitosis. Thought to be a trigger for mitosis. (18 Nov 1997) |
| plateau phase | <oncology> Stable stage of disease in multiple myeloma following good response to anti-cancer treatment. (31 Dec 1997) |
| continuous phase | The medium or fluid in which a disperse is suspended. Synonym: continuous phase, dispersion medium, dispersion phase, external medium. (05 Mar 2000) |
| coupling phase | The physical relationship of two syntenic genes. If they are on the same chromosome, they are said to be "in coupling" or "in the cis phase"; if on opposite members of a chromosome pair, "in repulsion" or "in the trans phase." (05 Mar 2000) |
| positive phase | The period following the negative phase, during which the opsonic index rises. (05 Mar 2000) |
| postimplantation phase | The time period between implantation and placentation. (12 Dec 1998) |
| postmeiotic phase | The stage following that of reduction of the chromosomes in the sexual cells, representing the mature forms of these cells, ending with the conjugation of the nuclei in the impregnated ovum. Synonym: postreduction phase. (05 Mar 2000) |
| postmitotic phase | The period of the cell cycle after cell division when there is synthesis of RNA and protein; it may last for a few hours in rapidly growing tissue or a lifetime in non-renewing cells such as nerve cells. Synonym: Gap1 phase, postmitotic phase. (05 Mar 2000) |
| postreduction phase | The stage following that of reduction of the chromosomes in the sexual cells, representing the mature forms of these cells, ending with the conjugation of the nuclei in the impregnated ovum. Synonym: postreduction phase. (05 Mar 2000) |
| poststationary phase | The period in the growth of a bacterial culture in which growth is declining. (05 Mar 2000) |