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Biomedical subjects

G Ravaglia

Publications and source records attributed to G Ravaglia.

At least 55 records · Page 3Linked to original sources
PubMed1994

The association of ageing with calcium active hormone status in men.

We measured calcium regulating hormones and bone mineral density (BMD) in 66 men (aged 24-88 years). Vitamin D (1,25(OH)2D) does not vary with age, parathyroid hormone (PTH) increases after the age of 65 (p < 0.01) together with a parallel increase in urinary (r = 0.46, p < 0.05) and nephrogenic cAMP (r = 0.63, p < 0.01), while BMD decreases with age (r = -0.52, p < 0.01). The finding of age-associated decreases in bone mass even in the presence of constant serum levels of 1,25(OH)2D within the normal range suggests that there is an onset of tissue resistance to vitamin D in the aetiopathogenesis of osteopenia in elderly men.

Adult↗
PubMed1994

Calcium regulating hormones in healthy elderly men: relation to intestinal calcium absorption.

Aged male subjects often have osteoporosis and it has been suggested that the cause is an age-related lack of vitamin D. We evaluated the calcium regulating endocrine mechanism in healthy aged males in order to verify this hypothesis. We studied serum levels of PTH and 1,25(OH)2D in relation to intestinal calcium absorption, radial bone mass density (BMD) and osteocalcin plasma levels in 30 healthy elderly men (61-88 yr.). 1,25(OH)2D levels and calcium absorption, assessed by oral strontium test, did not change with age with respect to a young control group. PTH was higher (p < 0.02) in the elderly than in the control group, and correlated positively with nephrogenous cAMP levels (p < 0.01; r = 0.65). Radial BMD (measured by single photon absorptiometry) was lower (p < 0.01) in elderly than in young subjects and negatively correlated with age (p < 0.01; r = -0.45). Osteocalcin levels, used as a mark of bone turnover, were unchanged. The data suggest that decreased 1,25(OH)2D levels are not a feature of normal male aging. Senile hyperparathyroidism could compensate for impairments in endogenous metabolism of vitamin D in elderly males and maintain calcium absorption at an efficient level, without increasing bone turnover.

Adult↗
PubMed1992

Metabolic changes in bone in old age.

The authors conducted a study on the effect of aging upon the factors which regulate calcium metabolism. Hormonal and biochemical tests were performed on samples from patients selected on the basis of sex, age, and other characteristics in order to determine the trend of these regulatory factors in middle and old age, with particular attention to osteoporosis in women. The authors propose several theories regarding the pathogenetic mechanisms of osteoporosis on the basis of this study as well as the literature.

Adult↗
PubMed1991

Dietary treatment for familial hypercholesterolemia--differential effects of dietary soy protein according to the apolipoprotein E phenotypes.

Familial hypercholesterolemia, one form of type IIa hyperlipidemia, usually responds poorly to standard low-lipid diets. To define the responsiveness to a soy-protein diet in this disease, one homozygous and twenty heterozygous type IIa patients were submitted to a 4-wk traditional hypocholesterolemic diet followed by 4 wk in which animal protein was substituted with texturized soy protein. Soy was then withdrawn for a further 4 wk. No significant changes in plasma lipids were observed during low-lipid diets. The soy diet, however, caused a marked decrease in total (-20.8%) and low-density-lipoprotein (-25.8%) cholesterol and in apolipoprotein B (-14.1%). The plasma cholesterol reduction was higher in patients with apolipoprotein E3/E3 or E3/E4 vs an almost negligible effect on E3/E2. These results confirm that soy-protein diets can lower cholesterol in type IIa patients with familial disease. Data on the sensitivity of patients with different apo-E isoforms agree with recent hypotheses suggesting that soy proteins may activate B,E receptors.

Adult↗
PubMed1982

[The male gonad in an adrenometabolic syndrome. Morpho-functional findings].

The hormonal and morphological features of the hypogonad condition observed in patients with Cushing's disease have been examined. Endocrine functional exploration carried out in 5 male patient showed normal gonadotropin incretion and excretion levels alongside a reduced plasma level of testosterone and an excess of suprarenal androgens, particularly DHA. Cytomorphological observation of the testicle not only confirms the state of gonadic functional quiescence, but makes it possible to exclude the existence of possible intrinsic changes which make gonads unable to respond to tropin stimulus. It is considered that, as is observed in normal humans under corticosteroid load, the excess of glycocorticoids in Cushing's disease depresses testicular endocrine activity, without activating feedback with gonadotrophic hypophysis, since the suprarenal androgens replace testosterone in the counter-regulation mechanism.

17-Hydroxycorticosteroids↗
PubMedDate not supplied

Klinefelter's syndrome in nontwin brothers and maternal XX/XXX mosaicism.

A case of two nontwin brothers, 19 and 17 years old, who had both Klinefelter's syndrome with a chromosomal mosaicism 46 XY/47 XXY, is reported here. The analysis of their mother's karyotype revealed a 46 XX/47 XXX mosaicism. It is hypothesized that the presence of an extra X chromosome in all three subjects could depend on the transmission of two X chromosomes from the mother to the sons or, less likely, on an increased liability to nondisjunction of the X chromosomes during one of the early mitotic divisions in the zygotes.

Adolescent↗