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Biomedical subjects

G M Molinatti

Publications and source records attributed to G M Molinatti.

At least 19 recordsLinked to original sources
PubMed1995

Diabetic retinopathy as a cause of blindness in the province of Turin, north-west Italy, in 1967-1991.

Diabetes is known to be a major contributor to blindness in industrialized countries but few data are available on the situation in Italy. As an introductory step to the implementation of permanent screening for diabetic retinopathy, a search was carried out on the causes of visual loss in the provincial territory surrounding Turin, the main city of North-West Italy. The case notes of all 4549 residents in the province who were certified blind between 1967 and 1991 were examined with regard to cause, age at onset, and year of onset of visual acuity < or = 1/20. Diabetic retinopathy was the second commonest cause of bilateral blindness (13.1% of cases), preceded by cataract (26.7%) and followed by myopia (11.1%), optic atrophy (8.9%), glaucoma (8.9%), retinitis pigmentosa (7.2%), and senile macular degeneration (4.1%). Diabetic retinopathy was the commonest eye disease among those who became blind between the ages of 50 and 70 and remained the leading cause of visual loss when the age groups 20 to 70 were pooled together. The incidence of diabetic retinopathy-related blindness did not show any trend to decrease over the 25 years investigated. It is concluded that, in spite of widespread availability of facilities for its assessment and treatment, diabetic retinopathy remains a leading cause of blindness in North-West Italy. This fully justifies the implementation of screening programmes and efficient referral chains for the early detection and prompt treatment of this complication of diabetes.

Adolescent↗
PubMed1995

Altered adrenocorticotropin and cortisol response to corticotropin-releasing hormone in HIV-1 infection.

Alterations of the hypothalamic-pituitary-adrenal (HPA) axis are common in HIV infection. To characterize further the site of these derangements and their possible causes, eight male drug addicts with symptomatic HIV infection (stage IV C2) underwent the following investigations: repeated baseline determinations of cortisol, adrenocorticotropin (ACTH), interleukin 1 beta (IL-1 beta), IL-6 and interferon alpha (IFN-alpha); and ovine corticotropin-releasing hormone (CRH) test (100 micrograms IV) for ACTH and cortisol determinations. Baseline cortisol levels were either normal or elevated in all patients. A significant linear correlation was found between baseline levels of cortisol and both IL-6 (r = 0.955; p < 0.001) and IL-1 beta (r = 0.863; p < 0.005), but not between cortisol and ACTH or between ACTH and circulating cytokines. Both ACTH and cortisol responses to CRH were nearly absent in six out of eight patients, and delayed in the others. The areas under the curves of both ACTH and cortisol after CRH were significantly lower in HIV patients than in a group of eight healthy control subjects (p = 0.0157 for ACTH and p = 0.046 for cortisol). Out data suggest the possibility of an inappropriate stimulation of the HPA axis in symptomatic HIV infection by HIV-induced release of cytokines, with a blunted pituitary and adrenal response to CRH.

Adrenocorticotropic Hormone↗
PubMed1995

Treatment of Cushing's disease by interstitial pituitary irradiation: short- and long-term follow-up.

Trans-sphenoidal intrasellar implantation of radioactive rods was employed to treat Cushing's disease in our Institution between 1958 and 1981. The patients were followed at regular intervals after the procedure. The aim of this work is to assess retrospectively the results, comparing the short- (1 year) and long-term (average 21.8 years) effects of this treatment. Seventy-six patients received pituitary implantation of 90Y- and one of 198Au-labelled rods, delivering a dose of 100-150,000 rad. Complete remission was obtained in a few weeks to months in 57/76 patients (5 of whom required a second implantation); 2 patients died of meningoencephalitis and 3 of cardiovascular complications associated with hypercortisolism 1 to 2 months after surgery. In 12 patients bilateral adrenalectomy or external pituitary irradiation were required to achieve remission; one of them developed Nelson's syndrome 15 years after implantation. Two were lost at follow-up. Long-term follow-up was possible in 41 patients of the initial series. Of these, 40 were cured of the disease, with hypoadrenalism developing in 25, while recurrence was observed only in the patient treated with 198Au. The incidence of hypothyroidism was 50%, and that of hypogonadism 54%. Permanent diabetes insipidus developed in 1 subject. GH deficiency resulting in retarded growth was found in the youngest patient, who had been operated at the age of 14. In conclusion, interstitial irradiation of pituitary adenomas was a safe and effective procedure for the treatment of Cushing's disease.

Adolescent↗
PubMed1994

Metabolic markers for the early diagnosis of postmenopausal osteoporosis.

We performed a cross-sectional study in 147 women, 41 in premenopausal age and 106 in menopause for 1-5 years: bone mineral density (BMD) at the distal radius and annual bone loss (as shown by plasma alkaline phosphatase and osteocalcin levels, and by calcium/creatinine and hydroxyproline/creatinine in the second urine of the morning) were evaluated. A significant reduction of BMD with a significant increase of bone loss was observed with increasing duration of menopause. Furthermore, when the women were subdivided into two groups according to annual bone loss (over or under 1.7%), significant differences were found between bone mineral density in the second and third years of menopause. As this is a cross-sectional and not a longitudinal study, it confirms that, in the presence of a higher bone loss, the BMD levels are lower and consequently the theoretical definition of this parameter can allow useful information on the presumable behavior of BMD.

Adult↗
PubMed1994

Alpha-melanocyte-stimulating hormone antagonizes the inhibitory effect of corticotropin-releasing hormone on luteinizing hormone secretion during the luteal phase in normal women.

CRH inhibits the secretion of gonadotropins by activating endogenous opioids, whereas alpha MSH, which displays various behavioral and neuroendocrine effects contrary to those of the opioids, stimulates their release. To evaluate the possible interaction of CRH and alpha MSH, eight women in the luteal phase underwent the following tests: 1) ovine CRH infused at 100 micrograms/h for 3 h, 2) alpha MSH (2.5 mg as an iv bolus 60 min after the start of saline infusion), 3) CRH plus alpha MSH (injected 60 min after the start of CRH infusion), and 4) placebo. LH, FSH, PRL, ACTH, and cortisol were determined every 15 min for 180 min. CRH significantly (P < 0.001) reduced serum LH. alpha MSH alone significantly (P < 0.001) increased LH to a peak within 15-30 min (baseline, 3.3 +/- 0.7 mIU/mL; maximum increase, 3.5 +/- 0.9 mIU/mL) and induced an even greater rise when injected during the CRH infusion (baseline, 2.8 +/- 03 mIU/mL; maximum increase 7.5 +/- 1.6 mIU/mL; P < 0.05 vs. alpha MSH alone). FSH was always unaffected. ACTH and cortisol increased (P < 0.001) during the CRH infusion and fell significantly (P < 0.001) during the placebo infusion. alpha MSH had no effect on these changes. PRL fell during the placebo infusion (P < 0.001). No changes were induced by CRH or alpha MSH. In conclusion, alpha MSH antagonizes CRH inhibition of LH secretion. This finding lends support to the view that differential posttranslational processing of POMC contributes to the regulation of LH secretion. Further investigation is needed to clarify the mechanism of the antagonism between alpha MSH and CRH.

Adrenocorticotropic Hormone↗
PubMed1993

The role of endothelium in the pathogenesis of diabetic microangiopathy.

Damage caused to the vessel wall by diverse mechanisms may lead to diabetic microangiopathy. Consequently, research work is more and more focusing on the pathophysiology of vascular cells, with particular emphasis on endothelium. This paper reviews the present knowledge on the alterations of small vessel endothelium in diabetes. The most important risk factors for diabetic microangiopathy are the duration of disease and the degree of metabolic control maintained throughout the years. However, genetic factors may also contribute. These are examined first, followed by the presumed roles played by increased protein glycation and the production of Advanced Glycosylation End Products, the "polyol pathway" and free radical generation. Endothelium is a widespread, extremely active organ which regulates complex physiologic functions and its structure and function are discussed in the second section of this review. The third part deals with how diabetes can affect endothelium and describes observations on endothelial metabolism in vitro as well as morphologic and functional alterations in the patients. Unfortunately, the mechanisms leading to progressive degeneration of the microcirculation and organ damage in diabetic patients remain largely unaccounted for.

Animals↗
PubMed1993

Clonidine lowers alpha-MSH-like immunoreactivity in human plasma.

In a group of seven healthy subjects, the effects of acute intravenous administration of clonidine, a selective alpha 2 receptor stimulator, on plasma alpha-MSH-LI concentrations were measured. In comparison with saline, clonidine (0.075 mg) significantly reduced alpha-MSH-LI concentrations, with a maximum fall between 30 and 60 min., followed by a return to basal concentrations at 120 min.; no significant variations in plasma ACTH and cortisol were seen. The precise mechanism of this effect is unclear. Our study suggests that separate regulatory mechanisms exist for the secretion of POMC related peptides in the corticotroph and melanotroph cells of the human pituitary gland.

Adrenocorticotropic Hormone↗
PubMed1993

Adrenergic regulation of alpha-MSH secretion in man: evidence for a stimulatory role of beta-receptors.

In several animal species the catecholamines stimulate the release of alpha-MSH from the melanotrope cells of the pituitary neurointermediate lobe through beta-receptors. The human hypophysis does not include a well-defined intermediate lobe and the methods for measuring alpha-MSH are often poorly sensitive. Neuroregulation of this hormone in man has thus received little attention. To see whether the adrenergic system is involved in the control of alpha-MSH secretion and whether the latter is independent of that of other peptides derived from proopiomelanocortin, such as ACTH, we studied the effects on plasma alpha-MSH-like immunoreactivity (alpha-MSH-LI), ACTH, and cortisol of some adrenergic drugs active on the beta-receptors. Six normal volunteers underwent the infusion of the following drugs: isoproterenol (0.03 microgram.kg-1.min-1 for 60 min), propranolol (1 mg.min-1 for 5 min followed by 0.1 mg.min-1 for 115 min), propranolol+isoproterenol (infused between 30 and 90 min of propranolol infusion), placebo (saline solution). Isoproterenol increased alpha-MSH-LI at 15 min (p < 0.001). Propranolol induced a fall of alpha-MSH-LI between 30 and 60 min (p < 0.001), followed by a return to preinfusion concentrations beginning at 75 min, and completely prevented the stimulatory effect of isoproterenol. Plasma ACTH and serum cortisol were always unaffected. These results indicate that in man the adrenergic system stimulates alpha-MSH-LI release through beta-receptors, and that alpha-MSH-LI secretion is dissociated from that of ACTH and cortisol. This in turn suggests that separate neuroregulatory mechanisms exist for the melanotrope and corticotrope cells.

Adrenocorticotropic Hormone↗
PubMed1993

[Virilization in women. Clinical and therapeutic aspects].

Androgenization in women can be divided, from a clinical standpoint, in two groups: a major form (with hirsutism, seborrhea, acne, hair loss, menstrual irregularities, masculinization of muscles and voice, mammary atrophy) and a minor one, with skin changes only (in particular hirsutism) with or without menstrual problems. The different clinical presentations are reviewed here: virilizing tumours of adrenal glands and ovaries, adrenogenital congenital syndromes, Cushing's syndrome and disease, iatrogenic forms, simple or idiopathic hirsutism, late onset enzymatic defects of adrenal steroidogenesis, polycystic ovary syndrome). The relevant therapeutic options are discussed. Special attention is devoted to the treatment of simple cutaneous androgenization, a problem affecting about 10% of women, by antiandrogenic drugs, mostly cyproterone acetate and spironolactone. These compounds compete with dehydrotestosterone for androgen cutaneous receptors, and have obtained good results, although not permanent. The indications, use and side-effects are also discussed.

Adrenal Gland Diseases↗
PubMed1993

[Role of the endothelium in the control of vascular motility: physiologic aspects and physiopathologic implications in cardiovascular diseases].

It was recently demonstrated that vascular endothelium produces many substances which modulate the vascular tone by acting locally (endothelium derived relaxing factor, angiotensin II, endothelin, prostacyclin). The authors review the physiological regulatory role of these substances and their involvement in cardiovascular diseases. They also consider the interaction between the endothelium derived factors and some cardiovascular drugs (such as calcium antagonists and ACE-inhibitors) and also the mechanisms of the possible protective action of these drugs on the vascular wall.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

[Male fertility in the elderly].

Fertility in the elderly is still a less known argument. We report some news about seminal parameters (SP) and testicular hystological parameters (THP) in this age. About SP: the volume of the ejaculate, the number and the motility of spermatozoa are reduced. The morphology is typical: spermatozoa with coiled tails are common. About THP: some testes show a normal hystological architecture; others show a reduced volume and some aspects of hypospermatogenesis or maturative arrest; others show a very reduced volume, thickness of the tubular basal membrane and other signs of cellular regression. These signs are dependent upon the vascular insufficiency and the hormonal alterations which may occur in the elderly.

Aged↗
PubMed1992

Influence of estrogens on calcitonin secretion.

In this study we investigated the calcitonin (CT) pattern both in basal conditions and after calcium infusion before and one month after oophorectomy in 17 premenopausal women. In addition, 13 oophorectomized women were randomly allocated to two groups, one given hormone replacement treatment and the other untreated, and CT response to hypercalcemia was reevaluated one year later. CT response to calcium infusion was significant only before oophorectomy and one year after estrogen-progestogen treatment, whereas there was no response one month after oophorectomy or after one year without hormone replacement therapy. Our data indicate that both estrogen secretion and replacement treatment may be important factors in CT response.

Adult↗
PubMed1992

Effect of testosterone on bone in hypogonadal males.

Bone mineral content (BMC) and testosterone levels were evaluated and compared in 10 hypogonadal males and 10 normal, age-matched controls. In 6 of the subjects an investigation was also carried out into the effects of testosterone administration on lumbar BMC, calcitonin (CT) response to hypercalcaemia, osteocalcin (BGP) and the fasting urinary calcium/creatinine and hydroxyproline/creatinine ratios. Our results confirm that male hypogonadism is characterized by a low BMC and that testosterone administration is able to improve this parameter and to increase both basal BGP and CT response to hypercalcaemia. Testosterone therefore probably acts on bone tissue through both a direct action on osteoblast cells and an improvement in CT secretion.

Adult↗
PubMed1992

Delayed replication of human umbilical vein endothelial cells in high glucose is corrected by L-tyrosine.

Human umbilical vein endothelial cells (HUVEC) cultured in high glucose exhibit delayed replication and colchicine-resistant microtubules. Tubulin dysfunction and stabilization, brought about by acetylation of the NH2-terminal residues, loss of the C-terminal tyrosine and binding of microtubular-associated proteins (MAPs) may be involved in the above phenomenon. The effects of L-tyrosine on HUVEC replication in high glucose were tested and the hypothesis that non-enzymatic glycosylation might impair tubulin depolymerization was also checked by growing the cells in the presence of L-glucose, which binds to intracellular proteins but remains metabolically inactive. After 18 days in culture, the number (mean +/- SEM, n = 7) of HUVEC grown in 28.0 mmol/l D-glucose (435.7 +/- 59.1 x 10(3)) was lower than in 5.6 mmol/l D-glucose (818.3 +/- 75.2 x 10(3)), p < 0.0001. The addition of L-tyrosine 1.7 mmol/l corrected such growth inhibition (623.3 +/- 81.7 x 10(3)), p < 0.0001 vs. D-glucose 28.0 mmol/l, but the cells recovered were less numerous than in physiological glucose alone (p = 0.016). The addition of L-tyrosine to D-glucose 5.6 mmol/l (731.0 +/- 63.2 x 10(3)) did not modify the cell number significantly. HUVEC in extra L-glucose (687.4 +/- 72.0 x 10(3)) were less numerous than in 5.6 mmol/l D-glucose, p = 0.028, but more than in D-glucose 28 mmol/l, p < 0.0001, and were not modified by the addition of L-tyrosine (729.4 +/- 67.1 x 10(3)). HUVEC grown in physiologic and high glucose exhibited specific immunofluorescence for acetylated tubulin and MAPs.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Division↗
PubMed1990

Primary pigmented micronodular disease of the adrenals.

Primary pigmented micronodular disease is a peculiar form of ACTH-independent Cushing's syndrome characterized by the familial occurrence, the frequent association with malformations and the pathological adrenocortical picture consisting in micronodules with cellular deposition of lipofuscinic pigment. We describe here a case occurring in a 14-year-old girl.

Adipose Tissue↗
PubMed1990

Vertebral bone loss in menopause.

A direct correlation between loss of ovarian function and reduction of bone mass is well established. The incidence of fractures sharply increases with age starting from the menopause. Therefore, it is very important to know the rate of bone loss occurring after menopause, at both trabecular and cortical levels. Several factors may contribute to the reduction of bone mass in menopause. Reduced estrogen secretion results in reduced intestinal calcium absorption, increased bone resorption, and probably a deficient production of calcitonin. Furthermore, in vivo and in vitro experimental data confirm that estrogen failure is associated with histologic changes, mirroring the biochemical changes described in postmenopausal osteoporosis.

Aged↗