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Biomedical subjects

D C Evans

Publications and source records attributed to D C Evans.

At least 55 records · Page 3Linked to original sources
PubMed1983

Action of somatostatin on stomach, pancreas, gastric mucosal blood flow, and hormones.

In dogs gastric secretion induced by tetragastrin and pancreatic secretion induced by secretin and/or cholecystokinin were inhibited by somatostatin at doses of 0.06-1 microgram X kg-1 X h-1 and 0.06-1 microgram X kg-1 X 0.5 h-1, respectively. Inhibition was a linear function of the logarithm of dose. Basal and 2-deoxy-D-glucose-induced gastric acid secretion was also significantly inhibited by low doses of somatostatin. Results in this study differ from those reported previously by clarifying the action of somatostatin as follows. 1) The inhibitory effect of somatostatin on pancreatic protein secretion was significantly greater than that on water and bicarbonate production. Somatostatin was more effective on cholecystokinin- than secretin-induced pancreatic secretion. 2) Although gastric mucosal blood flow (MBF) was affected by somatostatin, the reduction of MBF was not the primary mechanism responsible for its inhibitory action. 3) The low doses of somatostatin used in this study significantly inhibited gastric and pancreatic secretion without affecting the basal plasma concentrations of insulin, glucagon, growth hormone, gastrin, or secretin in the dogs, suggesting that the inhibitory action was not mediated by changes or reduction in plasma concentration of these hormones.

Animals↗
PubMed1983

Treatment of intertrochanteric fractures of the femur. A comparison of the Richards screw-plate with the Jewett nail-plate.

One hundred and seven patients with intertrochanteric fractures of the femur treated with a Richards screw-plate were compared retrospectively with 103 patients treated with a Jewett nail-plate. The mortality and morbidity were similar in the two groups. In patients with comparable fractures, those treated with a Richards device mobilised more quickly and left hospital sooner, and more of them returned to their homes. Failures of stabilisation, both clinically and radiographically, were fewer in this group. The reliability of fixation with a correctly positioned Richards screw-plate could justify the omission of outpatient follow-up in all but a small group of patients with severe unstable fractures or grossly defective bone stock. The higher cost of a Richards implant and the slightly longer operative procedure were outweighed by savings in occupancy of acute and long-stay hospital beds.

Adult↗
PubMed1982

Inhibitory effect of glucagon on gastric acid secretion induced by methacholine, insulin, tease-feeding and antral distention in dogs.

Acid secretion from Heidenhain pouches of dogs stimulated by methacholine was inhibited 34 to 45 per cent by glucagon (25 micrograms/kg subcutaneously or 25 micrograms/kg/hr by continuous intravenous infusion). Acid secretion induced by insulin was inhibited 25 to 62 per cent for 1 1/2 to 2 1/2 hr by a single s.c. dose of glucagon 10 micrograms/kg. Continuous intravenous infusion of glucagon 25 micrograms/kg/hr or of a hypertonic glucose solution (20 per cent w/v) reduced the response to 0.5 unit/kg of insulin by 78 to 84 per cent for more than 3 1/2 hr in 4 dogs with vagally innervated gastric pouch. The response to food teasing was decreased 66 to 99 per cent by 10 micrograms/kg of glucagon s.c. The acid response of vagally innervated fundic pouches to repeated distention of the pyloric region was completely abolished by 3 doses of 10 micrograms/kg. Glucagon is effective in inhibiting acid secretion induced by insulin, sham feeding and distention of the pylorus.

Animals↗
PubMed1981

Exophthalmos and elevated thyroxine levels in association with lithium therapy.

Although goiter formation and hypothyroidism are not infrequent following lithium therapy, the association of exophthalmos and/or elevated thyroxine levels with lithium is uncommon. We describe a 62 year old man who rapidly developed exophthalmos, elevated circulating thyroxine, elevated TSH levels and elevated radioiodine uptake within six weeks of reexposure to lithium carbonate. When the medication was stopped, all indices of thyroid function returned to normal and the proptosis receded from 22 to 17mm. Lithium decreases secretion of preformed thyroid hormone and the secondary elevation of TSH levels usually restores euthyroid status. We propose that in our patient, because triiodothyronine levels remained normal, the pituitary was refractory to the normal inhibitory feedback effect of thyroxine and that continued hypersecretion of TSH resulted in hyperthyroidism

Bipolar Disorder↗
PubMed1979

Empty sella secondary to suprasellar colloid cyst of foregut (respiratory) origin. Case report.

An enlarged sella turcica was discovered in a 40-year-old man who had bitemporal headaches. A pneumoencephalograph revealed a third ventricular cyst, dilated lateral ventricles, and an empty sella. The colloid cyst was lined by foregut epithelium, probably originating in the respiratory tract, and dense connective tissue. This case is the first instance of an empty sella associated with a colloid cyst of the third ventricle. It is proposed that enlargement of the mass in the third ventricle caused increased pulsation pressure of the cerebrospinal fluid, and that in the presence of an incompetent diaphragma sellae the subarachnoid space expanded into the sella. The origin of third ventricle cysts is reconsidered. It is concluded that suprasellar colloid cysts may arise from endoderm, ectoderm, neuroepithelium, or a combination of these epithelia.

Adult↗
PubMed1977

Bovine pancreatic peptide: action on gastric and pancreatic secretion in dogs.

Bovine pancreatic peptide (BPP) is a straight chain peptide containing 36 amino acid residues that has recently been isolated from pancreatic tissue. At a dose of 40 mug/kg-h intravenously, it stimulated gastric acid secretion when given alone but inhibited the submaximal secretion induced by the C-terminal pentapeptide of gastrin. Basal pancreatic secretion of dogs was inhibited by BPP (1-10 mug/kg-h) inhibited pancreatic protein secretion but often showed a biphasic action on water-bicarbonate response, an initial augmentation followed by reduction. BPP (2-5 mug/kg-h) inhibited pancreatic water-bicarbonate and protein secretions induced by an infusion of secretin plus cholecystokinin. Des-tyrosyl-NH2 BPP lacking the C-terminal tyrosyl amide, failed to inhibit gastric acid induced by C-terminal pentapeptide of gastrin or pancreatic secretion induced by secretin. BPP had no hyper- or hypoglycemic, hyperkalemic, or diuretic actions in the dog.

Animals↗
PubMed1976

The pelvic osteotomy of Chiari: an anatomical study of the hazards and misleading radiographic appearances.

The medial displacement osteotomy of Chiari has an established place in the management of older children and adults with severe hip dysplasia. The results claimed for the operation are, however, variable. There have also been reports of sciatic nerve lesions. In this study ten cadavers were operated upon. Chiari osteotomy was performed upon five, and five acted as controls. The hemipelvis was removed from each cadaver; each specimen was deep-frozen and sectioned transversely. The distance of the sciatic nerve from the nearest bony point was measured in each section and the results were recorded graphically. A further radiographic and photographic study was performed to determine whether apparent displacement at the osteotomy might be misleading. The conclusion was drawn that the sciatic nerve is angulated at the osteotomy and further endangered by the risk of bone splintering at the sciatic notch. The radiographic study suggested that some poor clinical results may be explained by a radiological artefact, because there is a tendency for the osteotomy to hinge posteriorly at the sciatic notch opening anteriorly like a book. Radiographs may suggest excellent medial displacement whereas in fact the femoral head is very poorly covered.

Adult↗
PubMed1975

Pentagastrin increases phenylalanine and decreases histidine incorporation to proteins of rat stomach.

Female rats were treated with L-phenylalanine-14C or L-histidine-14C, 20 mug/kg i.p. one hour before receiving pentagastrin 250 mug/kg s.c. Sixty minutes after injection of pentagastrin the incorporation of L-phenylalanine-14C into the proteins of the squamous and fundic portions of the stomach was significantly increased respectively by 18 and 17.5%. On the contrary, the uptake of Lhistidine-14C into the proteins of the squamous (-24%), fundic (-18% and duodenal (-16%) regions was significantly decreased. Incorporation of histidine and phenylalanine into the proteins of the pylorus was not significantly affected by pentagastrin.

Animals↗