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Biomedical subjects

C M Davidson

Publications and source records attributed to C M Davidson.

34 records · Page 2Linked to original sources
PubMed1991

Endoscopic transanal resection of rectal lesions: facilitation by adaptation of Lord's dilator.

A wide variety of techniques are available to remove lesions within the anal canal and rectum. Endoscopic transanal resection is a well tolerated procedure which achieves good palliation. Leakage of glycine from the rectum during the procedure can be problematic. To overcome this problem a Lord's dilator has been specially adapted to enable the passage of a urological resectoscope so preventing leakage of glycine during the procedure and improving operator acceptability. This technique of transanal resection with the adapted Lord's dilator provides a cheap and effective way of treating some rectal lesions largely utilizing existing equipment.

Anal Canal↗
PubMed1990

Increase in diacylglycerol mass in isolated glomeruli by glucose from de novo synthesis of glycerolipids.

An increase in glucose concentration in the medium from 5 to 30 mM transiently enhanced diacylglycerol mass and activated protein kinase C in glomeruli isolated from nondiabetic rats as assessed by translocation of enzyme activity from the soluble to particulate fraction. Effects of glucose on both diacylglycerol mass and protein kinase C were evident at 5 and 15 min but waned by 30 min. An increase in glucose concentration in the medium also increased the incorporation of [14C]glucose into the glycerol backbone of diacylglycerol, triacylglycerol, and phospholipids. Several observations implied that [14C]glucose was being incorporated into diacylglycerol through the de novo pathway for glycerolipid synthesis rather than being derived from phospholipids. 1) [14C]glucose incorporation into all the lipids was suppressed by 2-deoxyglucose. 2) The incorporation of [14C]glucose into diacylglycerol and triacylglycerol was evident by 1 min and increased linearly for at least 30 min. In contrast, incorporation into phosphatidylcholine occurred with a lag of at least 5 min. 3) Although only 10% of the [14C]glucose incorporated into lipids was present in diacylglycerol versus greater than 50% in phospholipids, the specific activity of [14C]glucose in diacylglycerol was fivefold higher than that in phospholipid when expressed as a function of mass. 4) Glucose had no effect on labeled diacylglycerol or phosphatidic acid production in glomeruli that had been prelabeled with [3H]glycerol. Glucose-induced increases in diacylglycerol may contribute to the activation of glomerular protein kinase C observed in early diabetes.

Animals↗
PubMed1988

Pelvic injuries associated with traumatic abduction of the leg.

We report a series of six severe pelvic injuries associated with traumatic abduction of the leg. All sustained a severe fracture of the pelvis associated with a deep perineal wound extending into the anus. Laparotomy was usually required to control haemorrhage and packing was only effective once the pelvis had been stabilized by external fixation. A sigmoid loop colostomy was required in all five initial survivors because of sphincter disruption, but three out of four long-term survivors are now fully continent. If mortality is to be reduced, blood loss must be rapidly controlled and sepsis prevented.

Accidents, Traffic↗
PubMed1985

Multifocal gastric carcinoid tumours, achlorhydria, and hypergastrinaemia.

Multiple polypoidal carcinoid tumours of the stomach were found in 5 patients with achlorhydria (4 of whom had pernicious anaemia) as a result of autoimmune atrophic gastritis. The tumours were small (nearly all less than 1 cm diameter) and appeared to grow very slowly, if at all; no significant enlargement or complications were seen during periods of observation of up to 6 years. No extragastric hormonal syndromes were identified. They differed from the carcinoid tumours usually found in the intestinal tract by being composed of argyrophil (not argentaffin) cells of the enterochromaffin-like (ECL) type. Fasting plasma levels of gastrin, which is believed to be trophic to ECL cells, were very high in all patients. Thus, chronic hyperplasia of gastric ECL cells (as a result of hypergastrinaemia) may have been responsible for development of the tumours. Long-term, uninterrupted achlorhydria produced by potent inhibitors of gastric acid secretion might therefore predispose to carcinoid tumours of the stomach.

Achlorhydria↗
PubMed1982

Management of retained cystic duct stones.

A 20-year-old woman underwent cholecystectomy and common bile duct exploration. Seven days later, T-tube cholangiography showed two stones retained in a developmentally anomalous cystic duct stump. She was treated with thrice-daily flushings of large amounts of saline through the T tube, and after 7 days of treatment the biliary system was free of stones. The conditions necessary for successful non-operative management of retained cystic duct stones are discussed.

Cholelithiasis↗
PubMedDate not supplied

Cleavage of amyloid precursor protein elicited by chronic cerebral hypoperfusion.

In the present study, we sought to determine whether low-grade, chronic vascular insufficiency induced in a rodent model of chronic cerebrohypoperfusion is sufficient, in and of itself, to trigger cleavage of the amyloid precursor protein (APP) into beta A-sized fragments. We report that chronic two vessel occlusion (2VO) results in progressive accumulation of beta A peptides detected by Western analysis in aged rats correlating with a shift in the immunohistochemical localization of APP from neurons to extracellular deposits in brain parenchyma. These data indicate that the 2VO paradigm reproduces features of beta A biogenesis characteristic of sporadic Alzheimer's disease.

Amino Acid Sequence↗
PubMedDate not supplied

Perinatal manganese exposure: behavioral, neurochemical, and histopathological effects in the rat.

Manganese chloride (Mn) was dissolved in the drinking water (0, 2, or 10 mg/ml) of dams and their litters from conception until postnatal day (PND) 30. Parturition was uneventful in the Mn-exposed rats and no physical abnormalities were observed. The rats exposed to 10 mg/ml Mn showed a 2.5-fold increase in cortical Mn levels. Their weight gain was attenuated from PND 9-24 and they were hyperactive at PND 17. Neither the 2 nor the 10 mg/ml Mn-exposed groups differed from the controls on the elevated plus apparatus or on the Morris water maze and the radial arm maze. Brain monoamine levels and choline acetyltransferase activity were affected. Tyrosine hydroxylase immunohistochemistry showed that dopamine cells of the substantia nigra were intact. Glial fibrillary acidic protein immunoreactivity was not increased in cortex, caudate, and hippocampus. However, both the low- and high-dose Mn-exposed groups showing thinning of the cerebral cortex. This could have resulted from perinatal malnutrition or from a direct effect of Mn on cortical development.

Analysis of Variance↗