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Biomedical subjects

M Schettino

Publications and source records attributed to M Schettino.

24 records · Page 2Linked to original sources
PubMed1991

Effects of exogenous growth hormone pretreatment on the pituitary growth hormone response to growth hormone-releasing hormone alone or in combination with pyridostigmine in type I diabetic patients.

We evaluated the effects of iv pretreatment with exogenous GH on the GH response to GHRH either alone or in combination with pyridostigmine in 14 Type I diabetic patients and 6 normal subjects. All the subjects received an iv bolus injection of biosynthetic human GH, 2 IU; 2 h later they received either a. pyridostigmine, 120 mg orally, or b. placebo, 2 tablets orally, followed 1 h later by iv injection of GHRH(1-29) NH2, 100 micrograms. In normal subjects the median GH peak after GH+ GHRH was 1.8, range 1.2-6.9 micrograms/l. Pyridostigmine enhanced the GH response to GHRH in all subjects. The median GH peak after pyridostigmine + GH + GHRH was 32.7, range 19.8-42.1 micrograms/l (p less than 0.001 vs GHRH alone). Seven diabetic subjects had median GH peaks after GH + GHRH greater than 6.9 micrograms/l (the maximum GH peak after GH + GHRH in normal subjects) (group A: median GH peak 35.7, range 21.7-55 micrograms/l). The other diabetic subjects had GH peak lower than 6.9 micrograms/l (group B: median GH peak 4.4, range 2.1-6.5 micrograms/l). Pyridostigmine significantly increased the GH response to GHRH in group B patients (median GH peak 29.3, range 15.7-93.4 micrograms/l, p less than 0.001 vs GH + GHRH alone), but not in group A patients (median GH peak 39.9, range 21.9-64.9 micrograms/l). Group A diabetic patients were younger and had higher HbA1c and blood glucose levels than group B patients. In those diabetic patients with an exaggerated GH response to GH + GHRH, pyridostigmine failed to cause the increase in GH secretion observed in diabetic and control subjects with no responses to GH + GHRH.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Effects of methimazole treatment on growth hormone (GH) response to GH-releasing hormone in patients with hyperthyroidism.

In vitro studies have demonstrated that thyroid hormones can enhance basal and stimulated growth hormone secretion by cultured pituitary cells. However, both in man and in the rat the effects of high thyroid hormone levels on GH secretion are unclear. The aim of our study was to test the GH response to human GHRH in hyperthyroid patients and to evaluate the effects on GH secretion of short- and long-term pharmacological decrease of circulating thyroid hormones. We examined 10 hyperthyroid patients with recent diagnosis of Graves' disease. Twelve healthy volunteers served as controls. All subjects received a bolus iv injection of GHRH(1-29)NH2, 100 micrograms. Hyperthyroid patients underwent a GHRH test one and three months after starting antithyroid therapy with methimazole, 10 mg/day po. GH levels at 15, 30, 45, 60 min and GH peak after stimulus were significantly lower in hyperthyroid patients than in normal subjects. The GH peak was also delayed in hyperthyroid patients. After one month of methimazole therapy, most of the hyperthyroid patients had thyroid hormone levels in the normal range, but they did not show significant changes in GH levels after GHRH, and the GH peak was again delayed. After three months of therapy with methimazole, the hyperthyroid patients did not show a further significant decrease in serum thyroid hormone levels. However, mean GH levels from 15 to 60 min were significantly increased compared with the control study. The GH peak after GHRH was also earlier than in the pre-treatment study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Influence of experimental illumination and seasonal variation on crossbreeding mating in the snail Biomphalaria glabrata.

The crossbreeding activities of the Schistosoma mansoni vector snail Biomphalaria glabrata were counted in a laboratory aquarium throughout the year under two regimes of 12h light: 12h dark from 7 A. M. to 10 P. M. Mating increased significantly in Autumn and Winter and just missed a significant inverse correlation with temperature and a direct one with locomotion. Other similar experiments were carried out to compare mating under various illumination conditions in complete daily cycle measurements. Mating counts decreased under the regimes which submitted snail to a total exposure of 12h light and 12h dark during a daily cycle in the following sequence: 12h light:12h dark alternating hourly with light gradient, 12h light:12h dark, 1h light:1h dark and 12h dark:12h light. Under two constant illuminations, the mating scored less than under the previous conditions, except under 12h dark:12h light. Under darkness the mating count was lower than under light conditions. There was no way to differentiate the night and day rhythms of mating on different days in each regime, except for mating under 12h light:12h dark alternating with light gradient, constant dark and 12h dark:12h light conditions. Mating increased in certain light and temperature conditions, in which the intensities should have an optimum value.

Animals↗
PubMedDate not supplied

[Effects of acute administration of nifedipine on exercise-induced microalbuminuria in normotensive patients with type 1 diabetes].

The aim of our study was to evaluate the acute effect of nifedipine, a calcium channel blocker, on exercise-induced microalbuminuria in normotensive and normoalbuminuric type 1 diabetic patients. Fifteen normotensive diabetic patients who were normoalbuminuric at rest (8 males and 7 females; age 16-35 years) and 10 normal subjects (6 males and 4 females; age 18-40 years) performed 4 submaximal cycloergometric exercises (90% of theoretical maximum heart rate); the first two exercises were performed in basal condition and the other 2 after 24 h of therapy with nifedipine AR (20 mg/b.i.d.) or placebo (2 cps/die). One hour after exercise in basal condition the microalbuminuria was 78 +/- 17 micrograms/min in diabetic patients vs 16 +/- 4 micrograms/min in normal subjects (p less than 0.001). After placebo no significant changes with respect to basal levels were observed 1 hour after exercise in either diabetic patients (82 +/- 16 microgram/min) or normal subjects (20 +/- 5 micrograms/min). In diabetic patients after nifedipine, systolic blood pressure was reduced both at rest and after exercise (p less than 0.05) with respect to basal condition or placebo. The urinary albumin excretion rate at rest was not modified, but it was significantly reduced 1 hour after exercise: 58 +/- 15 micrograms/min (p less than 0.01 vs placebo). This reduction correlated well with the reduction of exercise blood pressure in diabetic patients (r = 0.91, p less than 0.001). Our results indicate that acute administration of nifedipine reduced exercise-induced microalbuminuria in normotensive diabetic patients, probably by means of a reduction in exercise blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗