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Biomedical subjects

S J Herbert

Publications and source records attributed to S J Herbert.

5 recordsLinked to original sources
PubMed1993

Circadian neuroendocrine role in age-related changes in body fat stores and insulin sensitivity of the male Sprague-Dawley rat.

A role for circadian neuroendocrine rhythms in the age-related development of obesity and insulin resistance was investigated in the male Sprague-Dawley rat. The phases and amplitudes of the plasma rhythms of several metabolic hormones (i.e., corticosterone, prolactin, insulin, and triiodothyronine) differed in lean, insulin-sensitive (3-week-old rats), insulin-resistant (8-week-old rats) and obese, insulin-resistant (44-week-old rats) animals. Simulation of the daily rhythms of endogenous corticosterone and prolactin by daily injections of the hormones at times corresponding to the peak levels found in 3-week-old rats reversed age-related increases in insulin resistance and body fat in older (5-6-month-old) rats. Ten such daily injections of corticosterone and prolactin in 12-14-week-old rats produced long-term reductions in body fat stores (30%), plasma insulin concentration (40%), and insulin resistance (60%) (determined by a glucose tolerance test) measured 11-14 weeks after the treatment. Alterations in circadian neuroendocrine rhythms may account for age-related changes in carbohydrate and lipid metabolism in the male Sprague-Dawley rat, and resetting of these rhythms by appropriately timed daily injections of corticosterone and prolactin may help maintain metabolism characteristic of younger animals.

Adipose Tissue↗
PubMed1987

Growth and disease response of soybeans from early maturity groups to ozone and Fusarium oxysporum.

The single and combined effects of ozone (O(3)) and Fusarium oxysporum on growth and disease expression of soybean genotypes differing in foliar sensitivity to O(3) were studied in the greenhouse. O(3) had no effect on root and hypocotyl rot severity of PI 153.283 (O(3)-sensitive, S) or PI 189.907 (O(3)-tolerant, T) maturity group I soybean lines. Plants of both genotypes infected with F. oxysporum and exposed to O(3) had greater reductions in relative growth rate (RGR), net assimilation rate (NAR), and had more stippled leaves per plant than Fusarium-free plants exposed to O(3). O(3) alone had a greater impact on shoot dry weight, RGR, and NAR of PI 153.283 (S) than of PI 189.907 (T). O(3) alone reduced shoot and root dry weights primarily through a depression in NAR and less through reduced leaf area. F. oxysporum alone reduced root dry weight at 35 days; however, infected plants responded with increases in root dry weight from 49 to 63 days. Similarly, F. oxysporum alone lowered early RGR but subsequent RGR decline was less rapid while NAR remained high, particularly during later sampling intervals. Infection by F. oxysporum that causes root and hypocotyl rot increased soybean sensitivity to O(3) by prolonging active vegetative growth.

Journal Article↗
PubMed1975

Pneumothorax complicating pulmonary emphysema.

Clinical and roentgenographic findings were compared in patients 40 years of age and over and in those under 40 who were treated for acute unilateral pneumothorax. Dyspnea and anxiety were pominent in the older individuals, although pneumothoraces were usually small. Because physical findings were often unreliable, roentgenograms were required. In the presence of pulmonary emphysema, loss of retractility prevented total collapse of the underlying lung. Increased intrapleural pressure caused over-expansion of the chest wall and the depression of the diaphragm without much mediastinal shifting. Partial collapse of emphysematous lobes demonstrated bullae that were not previously obvious. Respiratory failure developed in five patients over 40 years of age, but four of them recovered after relief of the pneumothorax. Mortality for the group was low and related to associated pulmonary diseases.

Adolescent↗