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Biomedical subjects

J E Hunter

Publications and source records attributed to J E Hunter.

70 records · Page 4Linked to original sources
PubMed1978

Variable effects of iron status on the concentration of ferritin in rat plasma, liver, and spleen.

The present studies were conducted to determine the relationships between iron status and ferritin levels in plasma, liver, and spleen of rats. Rats were fed either iron-adequate or iron-deficient purified diets, and measurements of hemoglobin and plasma and tissue ferritin levels were made at various times during iron depletion and iron repletion. Although mean plasma ferritin concentrations of iron-deficient rats were directionally less than those of iron-adequate rats, these differences were not statistically significant due to high variability among similarly treated animals. During iron repletion plasma ferritin concentrations again were so variable that no significant effect of iron repletion on plasma ferritin concentrations was observed. On the other hand, liver and spleen ferritin concentrations of similarly treated rats were much less variable. Ferritin liver and spleen stores decreased more rapidly than hemoglobin during iron deficiency and were restored more slowly than hemoglobin during iron repletion. There was no evidence of correlation between liver and plasma ferritin concentration. Because of the variable responses of plasma ferritin concentration to iron depletion and repletion and the lack of relationship between plasma and liver ferritin concentrations, it is concluded that plasma ferritin concentration is not a good indicator of iron status in rats.

Animals↗
PubMed1977

Induction of pyridoxal phosphate-dependent enzymes in vitamin B-6 deficient rats.

The effectiveness of dietary and hormonal treatments in inducing several pyridoxal phosphate-(PLP)-dependent enzymes has been examined in vitamin B-6 deficient rats. Holo- and apoenzymes of serine dehydratase and ornithine aminotransferase were inducible in both control and deficient rats by feeding them 80% casein diets or by injecting them with glucagon. Holo- and apotyrosine aminotransferase were induced in both control and deficient rats by injecting them with glucagon or with dexamethasone phosphate. Phosphoenolpyruvate carboxykinase, a non-PLP-dependent enzyme, was inducible in both control and deficient rats by glucagon treatment if the rats were fed, but not if they had been starved. The degree of induction of certain enzymes depended upon whether rats were fed ad libitum, starved overnight, or fed a protein-free diet prior to the induction period. Phosphoenolpyruvate carboxykinase activities were about the same in both control and deficient rats. In vitamin B-6 deficient rats, both uninduced and induced activities of serine dehydratase, ornithine aminotransferase, and tyrosine aminotransferase assayed in the prsence of PLP, but not in its absence, either equaled or exceeded control values under most experimental conditions. Synthesis of excess of apoenzyme of PLP-dependent enzymes generally accounted for the high total enzyme activity in deficient rats. Differences between values for control and deficient rats could not be accounted for by differences in liver cyclic AMP concentrations nor were they apparently related to reduced food intake of the deficient rats. High apoenzyme concentration during depletion of coenzyme would tend to prevent depletion of active enzyme.

Animals↗
PubMed1976

Stability of some pyridoxal phosphate-dependent enzymes in vitamin B-6 deficient rats.

The effects of lowering the liver pyridoxal phosphate (PLP) concentration by vitamin B-6 deficiency on the stability of several rat liver enzymes were examined. Three PLP-dependent enzymes (serine dehydratase, ornithine-delta-aminotransferase, and tyrosine aminotransferase) and two non-PLP-dependent enzymes (glucose-6-phosphate dehydrogenase and phosphoenolpyruvate carboxykinase) were induced in vitamin B-6 deficient and control rats by feeding them high-protein diets or by injecting them with glucagon or dexamethasone. The decline of each activity was followed after withdrawal of the inducer. Serine dehydratase activity declined more rapidly in vitamin B-6 deficient than in control liver; however, ornithine aminotransferase and tyrosine aminotransferase activities were equally stable in deficient and control liver. Ornithine aminotransferase was predominantly in holoenzyme form in both control and deficient rats, whereas tyrosine aminotransferase was predominantly in apoenzyme form in both groups. The proportion of serine dehydratase in apoenzyme was less stable than the holoenzyme. Activity changes of glucose-6-phosphate dehydrogenase and phosphoenolpyruvate carboxykinase in control and vitamin B-6 deficient rats were similar. The results suggest that differences in the stability of PLP-dependent enzymes in vitamin B-6 deficient rats depend upon differences in the proportions of these enzymes existing as holo- and apoenzyme.

Animals↗
PubMed1976

Research and occupational therapy.

The quality and quantity of research in occupational therapy remains in its infancy. The following article is based on a study carried out in the spring of 1974, the objectives of which were to examine the role and function of the occupational therapist in clinical research, to identify areas in which occupational therapists have been involved in research and to examine the attitudes of registered therapists towards research.

Attitude of Health Personnel↗
PubMed1972

Salmonella testing of pooled pre-enrichment broth cultures for screening multiple food samples.

A method has been described for testing multiple food samples for Salmonella without loss in sensitivity. The method pools multiple pre-enrichment broth cultures into single enrichment broths. The subsequent stages of the Salmonella analysis are not altered. The method was found applicable to several dry food materials including nonfat dry milk, dried egg albumin, cocoa, cottonseed flour, wheat flour, and shredded coconut. As many as 25 pre-enrichment broth cultures were pooled without apparent loss in the sensitivity of Salmonella detection as compared to individual sample analysis. The procedure offers a simple, yet effective, way to increase sample capacity in the Salmonella testing of foods, particularly where a large proportion of samples ordinarily is negative. It also permits small portions of pre-enrichment broth cultures to be retained for subsequent individual analysis if positive tests are found. Salmonella testing of pooled pre-enrichment broths provides increased consumer protection for a given amount of analytical effort as compared to individual sample analysis.

Animals↗
PubMedDate not supplied

Child provocativeness and gender as factors contributing to the blaming of victims of physical child abuse.

This study was an investigation of factors contributing to blame attributions directed toward victims of physical child abuse. The total sample consisted of 897 college undergraduates. Subjects read eight vignettes describing physically abusive parent-child interactions, and indicated their attributions of responsibility toward parent and child. We predicted that: (a) aggressively provocative children (compared to nonprovocative) would be ascribed greater blame; (b) male subjects would be more likely to blame the child; (c) in situations in which the abusive parent is male (compared to female), the child would be blamed more; and (d) male children (compared to females) would receive greater blame. The results supported all hypotheses. The data also suggested several interaction effects. Significance tests were supplemented with effect size analyses.

Adolescent↗
PubMedDate not supplied

A mammalian cell agar-diffusion assay for the detection of toxic compounds.

A method using murine P-388 leukemia or human HT-29 colon carcinoma cells was developed for the bioautography of potential antitumor agents. Of 18 cancer chemotherapeutic drugs and natural products tested, all were detected by toxicity at 0.01 or 1.0 micrograms with P-388 cells, and 11 of the 18 were detected at 10 micrograms or less with HT-29 cells. Bioautography of a crude extract of Pseudoplexaura wagenaari and subsequent purification yielded the known compound crassin acetate. With modification, the assay detected specifically toxic DNA-binding agents.

Agar↗
PubMedDate not supplied

Hemidiaphragmatic paralysis as a complication of central venous catheterization in a neonate.

Central venous catheter placement has become commonplace in the care of the premature infant because of the need for long-term venous access. Although generally considered safe, there have been numerous reports of complications from the use of these catheters. We report the case of an infant in whom right hemidiaphragmatic paralysis developed after extravasation of fluid from a central venous catheter. The case emphasizes the need for continued vigilance of central venous catheter location and function.

Catheterization, Central Venous↗