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Biomedical subjects

R Shields

Publications and source records attributed to R Shields.

63 records · Page 4Linked to original sources

The effect of raising the concentration of potassium in the blood or intestinal lumen on the transport of potassium in the dog intestine.

The rates of transport of potassium, sodium and water across the intestinal mucosa of Thiry-Vella fistulas of colon and ileum, were studied in dogs in two experimental situations; (1) following intravenous infusion of potassium (15 mEg) over 30 minutes and (2) during variations in the intraluminal concentration of potassium in the range 0.8-16.0 mEg/l. Following intravenous infusion of potassium the rates of potassium secretion into the colon were usually increased; the rates of sodium and water absorption were either unchanged or decreased. The unidirectional rate of movement of potassium into the lumen increased as the concentration difference across the mucosa increased; the movement of potassium in the opposite direction remained relatively constant. The undirectional movement of sodium and water into the lumen of the colon also increased but to a lesser extent. The effect on potassium transport in the ileum was not so marked. With increase in the intraluminal concentration of potassium there was a decrease in the rate of net potassium secretion in both colon and ileum. The rates of net absorption of sodium and water were not significantly altered. Unidirectional potassium movement into the body increased in all the ileal fistulas.

Animals

Controlled clinical trial comparing early with interval cholecystectomy for acute cholecystitis.

The traditional management of acute cholecystitis is initial conservative treatment with antibiotics followed by elective cholecystectomy. Although early cholecystectomy has often been advocated, there has been only one randomized controlled clinical trial comparing the two methods of treatment. This paper reports the preliminary results of such a trial in which 32 patients have been studied so far. Of the 17 patients managed conservatively, there was a misdiagnosis in 2 (11-8 per cent). In the remaining 15 patients with acute cholecystitis 3 (20 per cent) required urgent operation because of failure of medical treatment. Elective cholecystectomy was not technically difficult. Of the 15 patients treated by early cholecystectomy, there was a misdiagnosis in 1 (6-8 per cent). Surgery was technically difficult in 2 patients but cholecystectomy was possible in all. The former 2 patients required blood transfusion, but in the remainder the estimated blood loss was only slightly more than in the elective group. There was no mortality in either group nor any complication directly attributable to the biliary surgery. The incidence of minor postoperative complications was only slightly greater in those treated by early operation. The length of postoperative stay was similar in both groups but those treated conservatively spent an average of 11 more days in hospital. The preliminary results indicate that those treated by early cholecystectomy spend less time in hospital and avoid the complications of failed conservative treatment without the added risk of increased postoperative mortality and major complications.

Acute Disease

Postprandial osmotic and fluid changes in the upper jejunum after truncal vagotomy and drainage in man.

The changes in osmotic pressure and the degree of marked dilution in the jejunal lumen after a hypertonic meal, have been studied in patients after truncal vagotomy and drainage, with and without diarrhoea, using an intraluminal intubation technique. The results suggest that neither the emptying of a hyperosmotic load from the stomach, nor its subsequent dilution in the jejunum have an important role in post-vagotomy diarrhoea.

Chromium Radioisotopes

Post-prandial changes in PH and electrolyte concentration, in the upper jejunum after truncal vagotomy and drainage in man.

The changes in pH and concentration of electrolytes in the jejunal lumen after a hypertonic fluid meal have been studied after truncal vagotomy and drainage, with and without diarrhoea. The results show that, in these respects, there are no specific changes in the jejunal content associated with post-vagotomy diarrhoea, but that these measurements are markedly affected by the completeness of vagotomy, as judged by the insulin test.

Chlorides

Effect of portacaval transposition on hepatic function in dogs with obstruction to the hepatic venous outflow.

Complete hepatic venous outflow obstruction (COB) in dogs resulted in impairment of hepatic function and cellular injury. Thus both the serum albumin concentration and the plasma clearance of indocyanine green (ICG) were reduced, whilst serum glycoproteins, aminotransferases and alkaline phosphatase levels were increased. Partial outflow block (POB)resulted in less severe functional changes although a significant decrease in serum albumin was also observed. The changes in liver function in dogs with portacaval transposition (PCT) and COB were generally similar to those in dogs with COB alone. However, the increases in serum enzyme activities and the decrease in plasma clearance of ICG were greater in the group with PCT. A late improvement in the clearance of ICG in dogs with COB and PCT was probably related to retrograde portal flow. When the hepatic lesion was only moderate (POB) PCT had little effect on either the liver function tests or plasma clearance of ICG, although no improvement in function was observed. It is concluded that PCT has no beneficial effect on dogs with either severe or moderate hepatic lesion and may cause further functional deterioration.

Alkaline Phosphatase