| retrograde menstruation | A flow of menstrual blood back through the fallopian tubes; it sometimes carries with it endometrial cells. Supplementary menstruation, bleeding from the navel or urinary tract due to endometriosis occurring at the time of menstruation. Suppressed menstruation, nonappearance of menstrual bleeding from whatever cause. Vicarious menstruation, bleeding from any surface other than the mucous membrane of the uterine cavity, occurring periodically at the time when the normal menstruation should take place. (05 Mar 2000) |
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| retrograde metamorphosis | An effect whereby the productivity of a microbial strain used in a commercial process diminishes after repeated transfer from one culture media to another, often caused by genetic mutation. (14 Nov 1997) |
| retrograde P wave | The P wave pattern in the electrocardiogram representing retrograde depolarisation of the atria, the impulse spreading from the A-V junction or the lower atrium upward. (05 Mar 2000) |
| retrograde pyelography | Pyelography in which contrast material is injected into the ureters from an endoscope in the bladder. (05 Mar 2000) |
| cholangiopancreatography, endoscopic retrograde | Fibreoptic endoscopy designed for duodenal observation and cannulation of vater's ampulla, in order to visualise the pancreatic and biliary duct system by retrograde injection of contrast media. Endoscopic (vater) papillotomy (sphincterotomy, endoscopic) may be performed during this procedure. (12 Dec 1998) |
| endoscopic retrograde cholangiopancreatogram | A diagnostic procedure to examine diseases of the liver, bile ducts and pancreas. It is uncomfortable but not painful, is performed under intravenous sedation, usually without general anaesthesia, and has a low incidence of complications. ERCP provides important information unobtainable by other diagnostic means. Therapeutic measures can often be take at the time of ERCP to remove stones in the bile ducts or to relieve obstructions of the bile ducts. (12 Dec 1998) |
| endoscopic retrograde cholangiopancreatography | <investigation, procedure> A diagnostic-therapeutic procedure that involves the X-ray of the pancreatic duct and biliary tree after the selective introduction of a contrast material into the common bile duct and pancreatic duct. In this procedure, a flexible endoscope is passed through the mouth and down into the duodenum. A catheter is then passed through the endoscope and inserted into the pancreatic and bile ducts. It is uncomfortable but not painful, is performed under intravenous sedation, usually without general anaesthesia, and has a low incidence of complications. A contrast agent is injected into the catheter which highlights the coarse and calibre of the ducts. Narrowing, stones or ductal tumours can be identified with this procedure. Therapeutic measures can often be take at the time of ERCP to remove stones in the bile ducts or to relieve obstructions of the bile ducts, so that traditional open surgeries can be avoided. ERCP is increasingly accepted as the diagnostic and therapeutic procedure of choice in identifying and removing gallstones in the bile ducts. Acronym: ERCP (12 Dec 1998) |
| alveolocapillary block | The presence of material that impairs the diffusion of gases between the air in the alveolar spaces and the blood in alveolar capillaries; block can be caused by oedema, cellular infiltration, fibrosis, or tumour, and results in undersaturation of peripheral arterial blood with oxygen. (05 Mar 2000) |
| anterograde block | Conduction block of an impulse traveling anywhere in its ordinary direction, for example, from the sinoatrial node toward the ventricular myocardium. (05 Mar 2000) |
| arborization block | Intraventricular block supposedly due to widespread blockage in the Purkinje ramifications and manifested in the electrocardiogram by a pattern similar to bundle-branch block but with complexes of low amplitude. (05 Mar 2000) |
| atrioventricular block | <cardiology> A conduction disturbance that results in the inappropriate delay (or complete inability) of a electrical impulse, generated in the atria, to reach the ventricles (via the atrioventricular node). Clinical types are divided into first (nonserious), second and third degree (most serious). Some drugs may precipitate atrioventricular block (for example clonidine, methyldopa, verapamil). A permanent pacemaker may be required for a third degree (complete) heart block. (02 Jan 1998) |
| autonomic nerve block | Interruption of sympathetic pathways, by local injection of an anaesthetic agent, at any of four levels: peripheral nerve block, sympathetic ganglion block, extradural block, and subarachnoid block. (12 Dec 1998) |
| A-V block | <cardiology> A conduction disturbance that results in the inappropriate delay (or complete inability) of a electrical impulse, generated in the atria, to reach the ventricles (via the atrioventricular node). Clinical types are divided into first (nonserious), second and third degree (most serious). Some drugs may precipitate atrioventricular block (for example clonidine, methyldopa, verapamil). A permanent pacemaker may be required for a third degree (complete) heart block. (02 Jan 1998) |
| block | An obstruction or stoppage. (18 Nov 1997) |
| block anaesthesia | Regional anaesthesia in which local anaesthetic solution is injected about nerves to inhibit nerve transmission; includes spinal, epidural, nerve block, and field block anaesthesia, but not local or topical anaesthesia. Synonym: block anaesthesia. (05 Mar 2000) |