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Biomedical subjects

J T Hindmarsh

Publications and source records attributed to J T Hindmarsh.

33 records · Page 2Linked to original sources
PubMed1986

Clinical and environmental aspects of arsenic toxicity.

Arsenic is widely distributed throughout the animal and plant kingdoms and our environment where sources can be natural or anthropogenic. Agricultural uses of arsenic have declined recently, but it still has well-defined roles in industry. Small amounts of arsenic are metabolized in a variety of ways and are largely rapidly methylated and excreted by man and animals. Poisoning can occur and may follow an acute or chronic course. Toxic manifestations in man occur at the cellular level and may appear in many organ systems. Specific effects can often be demonstrated in the skin and in the vascular and nervous systems. Other toxic effects appear to include carcinogenesis, mutagenesis, and teratogenesis.

Abnormalities, Drug-Induced↗
PubMed1986

The porphyrias: recent advances.

Recent research has elucidated several of the hitherto poorly understood steps in heme synthesis. This review describes this metabolic pathway and pinpoints the enzymatic blockages in the various porphyrias. Recent advances in the understanding of the etiology of porphyria cutanea tarda are discussed, as are the abnormalities of porphyrin metabolism seen in chronic renal failure and in lead poisoning. An outline is given of the clinical and biochemical abnormalities seen in the porphyrias. Included is an algorithm to aid in the differential diagnosis of these diseases, and a brief review of the new analytical techniques available for the identification and quantification of porphyrins and their precursors in body fluids.

Acute Disease↗
PubMed1977

Nitrogen-sparing effect of different feeding regimes in patients after operation.

In patients recovering from surgery, water, electrolytes, protein and calories all produce significant nitrogen sparing whether given by i.v. or intraduodenal routes. The nitrogen-sparing effect of protein and calories is greater when given to these patients via the gastrointestinal tract, and nitrogen equilibrium is approached when nutrients are supplied in amounts that satisfy theoretical requirements. I.v. regimes do not achieve nitrogen equilibrium, even when amino acids and calories are supplied in amounts that exceed theoretical requirements.

Adult↗
PubMed1976

Xylose absorption and its clinical significance.

1. Xylose absorption by the small intestine probably includes an active process. 2. For xylose testing, the 25-g dose appears to be preferable to 5 g. 3. Factors that influence the test result include intestinal bacterial overgrowth, reduced xylose metabolism in cases of liver disease, sequestration into ascites, age, and the state of renal function. 4. The test results differentiate patients with extensive disease of the upper small intestine from normal subjects, and from patients with steatorrhoea due to pancreatic insufficiency, in most but not all instances. Blood xylose levels combined with urinary xylose output aids discrimination.

Biological Transport, Active↗
PubMed1973

New jejunostomy feed.

Three patients with duodenal fistulae were fed solely with an easily prepared, inexpensive jejunostomy feed for 14, 21, and 23 days respectively. Sodium, potassium, and nitrogen balances became positive, diarrhoea did not develop, and body weight increased. The feed was life-saving: the patients' superficial veins were thrombosed, and percaval feeding was considered undesirable.

Animals↗
PubMed1967

Further studies on intestinal active transport during semistarvation.

1. The effect of semistarvation (sufficient to produce a loss of 18-28% of initial body weight) on the active transport of D-glucose and L-histidine by the rat, the guinea-pig and the golden hamster has been investigated by the use of sacs of everted small intestine (from upper jejunum to lower ileum).2. In the rat and the guinea-pig the dietary restriction resulted in increased active transport in all regions of the small intestine. In contrast, it caused no alteration in active transport in the hamster.3. The response in the rat was most impressive in the middle-to-lower ileum during D-glucose uptake. Whereas normal sacs from this area appeared unable to move the sugar against its concentration gradient, sacs from semistarved rats did so quite well.4. Although there was a considerable loss (24-29%) of intestinal dry weight in all three species when the food intake was reduced, shortening of the small intestine was not detectable in the guinea-pig or the hamster and was present to only a minor extent in the rat.5. Evidence is presented indicating that the enhanced active transport is not merely a reflexion of the thinning of the intestinal wall and that it occurs during complete as well as in partial starvation.

Animals↗
PubMed1966

Effect of amino acids on sugar absorption.

1. Sacs of everted mid-small intestine of the hamster have been used to study the effect of amino acids on sugar absorption.2. The sugars employed were D-glucose, D-galactose, 3-O-methyl-D-glucose, D-fucose, L-glucose, alpha-glucoheptose, L-fucose, D-mannose and L-sorbose. The amino acids were L- and D-histidine, L- and D-methionine, L- and D-alanine, L- and D-valine, L- and D-glutamic acid, L-leucine, L-proline, L-ornithine and L-aspartic acid.3. Actively absorbed amino acids considerably inhibit the transport of actively absorbed sugars. The results give support for the view that D-histidine and L-glucose are actively transferred. Passively absorbed amino acids and sugars are not involved.4. As L-glutamic and L-aspartic acids in the mucosal fluid have no inhibitory effect on D-glucose absorption, although mucosal fluid L-alanine is quite potent, the step at which the latter exerts its inhibitory action must be before that at which the intracellular transamination of L-glutamic and L-aspartic acids occurs. It would seem likely, therefore, that L-alanine interferes with the process by which epithelial cells capture and concentrate sugars at the luminal border.5. More than one active transfer system may exist for D-glucose.6. The influence of actively absorbed L-amino acids on D-glucose active transport seems to be in some way related to the efficiency with which the amino acids are themselves concentrated.7. Inhibition of D-glucose active absorption by an amino acid may be a simple test of an amino acid's participation in an active transport system.

Alanine↗
PubMed1966

The effect of amino acids on the intestinal transport of L- and D-xylose in vitro.

1. The intestinal transport of D-xylose by sacs of everted small intestine of the hamster is partially inhibited by L-histidine in concentrations of 5, 10 and 20 mM but not of 2 mM.2. 20 mM concentrations of D-histidine and L-methionine also produce inhibition.3. The inhibition is not due to an alteration in water transport or to a change in pH of the incubating medium.4. The rate of the intestinal transport of L-xylose is about (1/4) of the rate of D-xylose transport and is unaffected by a 20 mM concentration of L-histidine.

Amino Acids↗