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Biomedical subjects

D Herbert

Publications and source records attributed to D Herbert.

63 records · Page 4Linked to original sources
PubMedDate not supplied

Growth and reproductive adaptation in male rats with chronic protein deficiency.

In previous studies, male rats fed a low-protein diet beginning at weaning were found to have impaired sexual development through age 11 weeks when compared to food-restricted, weight-matched controls fed a diet with normal protein content. To determine whether male rats show long-term adaptation of the reproductive axis to low-protein feeding, we assessed sexual maturation and growth in rats fed a low protein (9%) diet from weaning until sacrifice at various points in time between ages 79 and 185 days. After age 80 days, there was no difference in reproductive organ weights (prostate, seminal vesicles, testis) or serum hormone levels (luteinizing hormone, follicle stimulating hormone, testosterone) between protein-deficient animals and food-restricted weight-matched controls given a normal diet. In addition, there was no difference between protein-deficient animals and controls in indices of linear growth (naso-anal and tail length) or fatness (Lee index). We conclude that both growth and reproductive function of male rats show adaptation to long term feeding of a low-protein diet.

Adaptation, Biological↗
PubMedDate not supplied

Sexual maturation in underfed weight-matched rats. A test of the "critical body weight" theory of pubertal timing in males.

A popular current theory proposes that the timing of puberty is related to attainment of a critical level of body weight or body fatness. These critical body weight and critical body fat theories have been studied almost exclusively in females. To explore these theories in males, we tested a corollary of these hypotheses: are male rats of the same weight all at the same level of sexual maturation irrespective of prior growth rate? Male rats growing in body weight at five different rates due to various degrees of underfeeding (beginning at weaning) were sacrificed at body weight milestones of 123 and 279 grams. At the first weight milestone, significant (P less than 0.01) inverse correlations were observed among these weight-matched rats between the preceding rate of body weight growth and prostate weight, seminal vesicle weight, testis weight, serum testosterone, and daily sperm production rate, indicating that the underfed animals were more sexually mature. Testis histology also showed that spermatogenic development increased progressively as the prior rate of body weight growth was reduced. These parameters of sexual maturation tended to correlate inversely with body fatness (i.e., leaner animals were more sexually mature) and directly with body length (i.e., longer animals were more sexually mature). By the second body weight milestone, however, the degree of prior underfeeding exerted little effect on those indices of sexual development. We conclude that the degree of sexual maturation in weight-matched animals with varying previous patterns of body weight growth correlates inversely with body fatness and the rate of body weight growth but correlates directly with body length.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMedDate not supplied

Xenon and iodine enhanced cerebral CT: A closer look.

Xenon and iodine enhanced dynamic computerized tomography (CT) have been used experimentally to obtain both qualitative and quantitative information on local cerebral blood flow in both normal and infarcted tissue. Direct comparisons between Xenon enhancement, iodine enhancement and pathological findings demonstrate significant differences between results derived from each of the 2 in vivo techniques. While iodine enhanced dynamic CT yields valuable information concerning the patency and density of vasculature, xenon enhanced studies can provide highly focal information on cerebral tissue perfusion.

Animals↗
PubMedDate not supplied

Observations on the cultivation of M. leprae and M. tuberculosis in medium 'V' and 'V 1'.

Skin scrapings from five different active sites were collected from 14 leprosy patients and inoculated into medium V. Skin scrapings from three leprosy patients were inoculated into medium V 1. All the cultures were incubated at 8-10 degrees C. M. tuberculosis H37Rv, pretreatment isolates and streptomycin resistant strains were inoculated into medium V, with and without antibiotics, and incubated at 8-10 degrees C as well as 37 degrees C. Smears were made from the M. leprae and M. tuberculosis cultures at 0 hours and at different time points. The number of bacilli in the smears were counted. There was no increase in the number of M. leprae or M. tuberculosis in any of the cultures.

Culture Media↗
PubMedDate not supplied

In vitro experiments with Centella asiatica: investigation to elucidate the effect of an indigenously prepared powder of this plant on the acid-fastness and viability of M. tuberculosis.

The herb Centella asiatica (Linn.), found throughout India, is acclaimed to have medicinal properties and has been used in leprosy patients from very early times. It is considered that the active compound of this herb, called asiaticoside, probably acts on the waxy covering of M. leprae. The in vitro effect of an indigenously produced dry powder of Centella asiatica (CA) on the acid-fastness and viability of M. tuberculosis was investigated in the present study. The results indicate that CA may not have any direct action on the acid-fastness or viability of M.tuberculosis H37Rv in vitro. Further studies using purified asiaticoside of the plant or in vivo studies are required.

Microbial Sensitivity Tests↗