| PSA | <tumour marker> A simple blood test used to detect prostate cancer in men. The test measures a specific antigen normally secreted by the prostate. If cancer is developing, the prostate secretes greater amounts of prostate-specific antigen. This test is recommended for men with an enlarged prostate and an increased risk of prostate cancer. It is an enzyme that is produced by epithelial cells of both benign and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer. It is a single chain 31 kilodalton glycoprotein with 240 amino acid residues and 4 carbohydrate side chains that is a kallikrein protease. It is found in normal seminal fluid and produced by the prostatic epithelial cells. Elevated levels in blood serum are associated with prostatic enlargement and prostatic adenocarcinoma, and this allows early detection of cancer in many cases. In about 70% of cases, the rise is due to a cancerous condition. No large scale clinical studies have been completed to assess the impact of testing on survival from prostate cancer, and the medical and economic value of testing remain uncertain. Acronym: PSA Registry number: EC 3.4.21.77 (22 Sep 2002) |
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| psalmist | 1. A writer or composer of sacred songs; a title particularly applied to David and the other authors of the Scriptural psalms. 2. A clerk, precentor, singer, or leader of music, in the church. Origin: L. Psalmista, Gr., cf. F. Psalmiste. See Psalm. Source: Websters Dictionary (01 Mar 1998) |
| psalmograph | A writer of psalms; a psalmographer. See: Psalmographer. Source: Websters Dictionary (01 Mar 1998) |
| psalmographer | A writer of psalms, or sacred songs and hymns. Origin: L. Psalmographus, Gr.; a psalm + to write. Source: Websters Dictionary (01 Mar 1998) |
| psalmographist | A writer of psalms, or sacred songs and hymns. Origin: L. Psalmographus, Gr.; a psalm + to write. Source: Websters Dictionary (01 Mar 1998) |
| psalmography | The act or practice of writing psalms, or sacred songs. Origin: Cf. F. Psalmographie. Source: Websters Dictionary (01 Mar 1998) |
| psalter | 1. The Book of Psalms; often applied to a book containing the Psalms separately printed. 2. Specifically, the Book of Psalms as printed in the Book of Common Prayer; among the Roman Catholics, the part of the Breviary which contains the Psalms arranged for each day of the week. 3. A rosary, consisting of a hundred and fifty beads, corresponding to the number of the psalms. Origin: OE. Psauter, sauter, OF. Sautier, psaltier, F. Psautier, from L. Psalterium. See Psaltery. Source: Websters Dictionary (01 Mar 1998) |
| psalterial | Relating to the psalterium. (05 Mar 2000) |
| psalterial cord | The stratified epithelium lining the upper part of the ligamentum spirale cochleae; it is penetrated by capillaries and is believed to be the site of production of endolymph. Synonym: stria vascularis ductus cochlearis, psalterial cord, vascular stripe. (05 Mar 2000) |
| psalterium | Origin: L, a psaltery. <anatomy> The third stomach of ruminants. See Manyplies. The lyra of the brain. Source: Websters Dictionary (01 Mar 1998) |
| psammite | <chemical> A species of micaceous sandstone. Psammit"ic. Origin: Gr. Sandy, from sand: cf. F. Psammite. Source: Websters Dictionary (01 Mar 1998) |
| psammo- | Sand. Origin: G. Psammos (05 Mar 2000) |
| psammocarcinoma | <tumour> Obsolete term for a carcinoma that contains calcified foci resembling psammoma bodies. (05 Mar 2000) |
| psammoma | <tumour> Obsolete term for psammomatous meningioma or meningioma. Origin: psammo-+ G. -oma, tumour (05 Mar 2000) |
| psammoma bodies | Mineralised body's occurring in the meninges, choroid plexus, and in certain meningiomas; composed usually of a central capillary surrounded by concentric whorls of meningocytes in various stages of hyaline change and mineralization; can also occur in benign and malignant epithelial tumours (often papillary) or with chronic inflammation. Synonym: sand bodies. Synonym: corpora arenacea. Synonym: calcospherite. (05 Mar 2000) |