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Biomedical subjects

E Stevens

Publications and source records attributed to E Stevens.

At least 73 records · Page 4Linked to original sources
PubMed1981

cis-Platinum(II)diamminodichloride-induced mutagenesis in E. coli K12: crowding depression of mutagenesis.

Cis-Platinum(II)diamminodichloride (cis-PDD)-induced mutations to prototrophy were studied in Escherichia coli. Mutagenesis was not detected in a recA nor in a lexA mutant, but was greater in a uvrA strain than in a repair-proficient strain, at a given treatment of cis-PDD. Increasing the plating density above 10(5) cells per plate did not give an equivalent increase in revertants per plate [crowding depression of mutagenesis (Bockrath et al., 1980)]. Growth rates were similar at different plating densities and crowding depression of mutagenesis was observed in both excision-proficient and excision-deficient strains. A filtrate of a plate wash from crowded plates, of either treated or untreated cultures, further reduced the mutation frequencies over that due to crowding depression of mutagenesis.

Cisplatin↗
PubMed1981

A controlled clinical trial of "family care" compared with "child-only care" in the comprehensive primary care of children.

We performed a randomized controlled clinical trial in a health center serving a poor population to attempt to find the differences, if any, between the effectiveness of primary care provided to children by two patterns of comprehensive medical care practiced by a pediatrician-internist-allied health team--one pattern offering care exclusively to children and the other offering care to both children and their parents. The study demonstrated few measurable differences between the two groups of children in either utilization or outcome. Where there were differences, most tended to favor slightly the family pattern of care: older children maintained their use of the center, immunization was somewhat more timely and children over time appeared to make fewer visits to sources of ambulatory care other than the health center. The absence of more or greater measurable differences may be due to the relatively short period of study, to the extremely disadvantaged population served, to the special model of family care used or to the comprehensive, team-based care provided to both groups of children.

Adult↗
PubMed1981

Phentolamine therapy in severe chronic asthmatiform bronchitis.

Continuous phentolamine infusion for 3 days in 6 patients with severe chronic bronchial obstruction produced a marked improvement in subjective well-being and arterial blood gas values. Ventilatory function and pulmonary arterial pressure remained virtually unchanged but a chronic oral corticosteroid therapy could be substantially reduced during 4 weeks of oral treatment with phentolamine 100 mg three times daily.

Adult↗
PubMed1980

A controlled trial of magnesium dithiosalicylate compared with aspirin in rheumatoid arthritis.

The anti-inflammamtory effectiveness and side-effects of magnesium dithiosalicylate were compared to aspirin in a 3-month, parallel, double-blind trial in 40 patients suffering from active rheumatoid arthritis. The results showed that 3 g magnesium dithiosalicylate daily had anti-inflammatory properties similar to those of 3 g aspirin daily in rheumatoid arthritis. A statistically significant change in morning stiffness, number of tender joints, pain score and erythrocyte sedimentation rate was observed in the magnesium dithiosalicylate group. In the magnesium dithiosalicylate group, 8 patients had to be withdrawn from the trial because of serious side-effects compared to 5 in the aspirin group. Gastro-intestinal intolerance occurred as frequently in both treatment groups. Hypersensitivity to magnesium dithiosalicylate was a serious problem and the reason for withdrawal in 4 cases. The high frequency of side-effects to magnesium dithiosalicylate makes this drug unacceptable for treatment of rheumatoid arthritis at the present time. Further pharmacological studies might reveal new derivatives which are as effective but with less side-effects. The anti-inflammatory activity of magnesium dithiosalicylate resembled that observed with gold and penicillamine. The fact that all these drugs have a sulphhydril group in common is stressed.

Adult↗
PubMed1979

The effect of restricted hydration on the rate of reaction of glucose 6-phosphate dehydrogenase, phosphoglucose isomerase, hexokinase and fumarase.

A method is described for the measurement of enzyme activity under xeric conditions. The reaction mixtures had water contents ranging between 0.1 and 0.6g/g of reaction mixture. For glucose 6-phosphate dehydrogenase, hexokinase and fumarase, enzyme activity became detectable (about 0.05% of the fully hydrated rate) when the water content was about 0.2g/g of reaction mixture, and for phosphoglucose isomerase, around 0.15g/g of reaction mixture. With the water content raised to 0.3g/g of reaction mixture the reaction rates were only increased to 0.1-3% of the fully hydrated rate. When the combined rates for phosphoglucose isomerase and glucose 6-phosphate dehydrogenase were measured, reasonable agreement was found between the experimental data and those calculated from the individual experimentally determined rates on the assumption that diffusion was not further limiting. A method was devised for measuring the diffusion coefficients of low-molecular-weight substances in solutions having low water contents. The diffusion coefficients of riboflavin in sorbitol solution decreased by about 100-fold when the water content of the latter was reduced from 3 to 0.25g/g of sorbitol. It is concluded that to detect enzyme activity a certain minimal amount of water is required and that above this minimum the rate is still restricted by diffusion limitation. The relevance of the results to the physical state of water in reaction mixtures and to metabolism in seeds and spores in xeric conditions is discussed.

Diffusion↗
PubMed1979

Assessment of the association between habitual salt intake and high blood pressure: methodological problems.

Despite the finding in cross-cultural comparisons that habitual sodium intake correlates with levels of blood pressure, similar studies from within population groups have yielded inconsistent results. The data presented in this report indicate that in industrialized societies the high degree of intra-individual variability of sodium intake, compared to much smaller inter-individual differences, may obscure potential biological correlations. A quantitative statistical method is presented to assess and minimize the effect of the large intra-individual variation in daily urinary sodium excretion.

Adult↗
PubMed1979

[Specific renal lesions revealing the presence of sarcoidosis (author's transl)].

Three cases of granulomatous nephropathy are reported. In two patients this was definitely related to a true renal sarcoidosis, while the third case raised the problem of the significance of an "isolated sarcoidosis nodule". The authors discuss the frequency, clinical symptoms, and pathological appearances of these renal lesions which reveal the presence of sarcoidosis, as well as the relationship between renal insufficiency and the parenchymatous lesions observed, and therapy.

Aged↗
PubMed1978

[Possible non-immunologic mechanism in atopic bronchial asthma].

A constitutional factor, an imbalance of cAMP/cGMP, a disturbance of adenylcyclase and a vegetative dysregulation influence the allergic type I reaction. An unspecific hyperreactivity of the bronchial system plays an important role in the asthmatic genesis. Own experiments with acetylcholine and anticholinergic drugs are described. The deduction that the complement system participates in bronchial asthma is likely from own in vivo and in vitro experiments.

Asthma↗