| plastic section stain | <technique> For electron microscopy, a stain (e.g., osmic acid, PTA, potassium permanganate) used on thin sections of plastic-embedded tissues, utilizing differential attachment of heavy atoms to various cellular and tissue structures so that electrons will be absorbed and scattered by these structures to produce an image; to achieve differential staining, the stain must penetrate nonwettable plastic embedments, for light microscopy, a stain (e.g., alkaline toluidine blue, silver methenamine) used on plastic-embedded tissues to attain higher resolution and more detail than normally possible; semi-thick (0.5-1.5 um) sections are particularly useful in renal pathology, especially in combination with the phase microscope. (05 Mar 2000) |
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| plastic surgeon | A surgeon who specialises in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases (such as melanoma). (12 Dec 1998) |
| plastic surgery | The surgical specialty or procedure concerned with the restoration, construction, reconstruction, or improvement in the shape and appearance of body structures that are missing, defective, damaged, or misshapen. (05 Mar 2000) |
| plastic teeth | Artificial teeth constructed of synthetic resins. (05 Mar 2000) |
| surgery, plastic | The branch of surgery concerned with restoration, reconstruction, or improvement of defective, damaged, or missing structures. (12 Dec 1998) |
| tissue culture plastic | <cell culture> Polystyrene that has been rendered wettable by oxidation, a treatment that increases its adhesiveness for cells from animal tissues and without which anchorage dependent cells will not grow. Commercially achieved by treatment known as glow discharge. (18 Nov 1997) |
| Gant's clamp | A right-angled clamp used in haemorrhoidectomy. (05 Mar 2000) |
| Gaskell's clamp | An instrument for crushing the atrioventricular bundle in experimental animals and thus producing heart block. (05 Mar 2000) |
| Rankin's clamp | A three-bladed clamp used in resection of colon. (05 Mar 2000) |
| gingival clamp | A springlike metal piece encircling or grasping the cervix of a tooth and shaped so as to retract the gingival tissue. (05 Mar 2000) |
| 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-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) |
| Payr's clamp | A clamp used in gastrectomy or enterectomy. (05 Mar 2000) |
| glucose clamp technique | <technique> Maintenance of a constant blood glucose level by perfusion or infusion with glucose or insulin. It is used for the study of metabolic rates (e.g., in glucose, lipid, amino acid metabolism) at constant glucose concentration. (12 Dec 1998) |
| voltage clamp | <physiology, technique> A technique in electrophysiology, in which a microelectrode is inserted into a cell and current injected through the electrode so as to hold the cells membrane potential at some predefined level. The technique can be used with separate electrodes for voltage sensing and current passing, for small cells, the same electrode can be used for both. Voltage clamp is a powerful technique for the study of ion channels. See: patch clamp. (18 Nov 1997) |