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Biomedical subjects

N Sicolo

Publications and source records attributed to N Sicolo.

At least 37 records · Page 2Linked to original sources
PubMed1989

Possible involvement of endogenous opioids in beta-cell hyperresponsiveness in human obesity.

Since increased opiate production in obesity has been reported, the effects of naloxone in obese subjects were studied in order to ascertain whether endogenous opioid peptides play a role in the abundant insulin secretion of obesity. The results obtained showed that intravenous administration of naloxone considerably reduced insulin of obese subjects to a mixed meal, whereas it did not modify the blood insulin response to arginine or glucose infusion. Glucagon secretion to ingestion of a mixed meal and to arginine infusion was not modified by the opioid receptor blocking agent. This study seems to indicate that hyperproduction of endogenous opioid peptides in obesity increases insulin secretion stimulated by food intake, whereas it does not appreciably affect insulin production stimulated by circulating glucose or aminoacids.

Adolescent↗
PubMed1988

Acromegalic cardiomyopathy. An echocardiographic study.

Eighteen acromegalic patients (A) and 18 controls without clinical evidence of cardiac involvement and/or endocrine disease (C), matched for sex, age, body surface area, and blood pressure (BP), were investigated by M-mode (2-D derived) echocardiography, to clarify the prevalence and the possible determinants of left ventricular hypertrophy (LVH). Seven patients in each group were hypertensive (BP greater than 160/95 mmHg). Left ventricular mass (LVM) was 183.1 +/- 60.0 g/m2 in A and 130 +/- 25.9 g/m2 in C. A LVM above 140 g/m2 (that is the upper normal range in our laboratory) was found in 15/18 A and 2/18 C. The LVH was concentric (h/r greater than 0.45) in 12/15 A and 1/2 C. Systolic function indexes (% FS, end-systolic stress/end-systolic volume), cardiac index and total peripheral resistance index (as determined by echo) were within the normal range and similar in both groups. No correlation was found between LVM and BP, LVM and GH plasma levels, LVM and Sm-C levels. A significant correlation was found between LVM and duration of the disease (r 0.44; p less than 0.05). Our data confirm that LVH is an early and frequent finding in acromegaly. Its prevalence is not entirely accounted for by such factors as body size, BP or increased cardiac output. Metabolic factors may play a major role, and a long lasting exposition to increased GH levels seems the most relevant determinant of LVH.

Acromegaly↗
PubMed1986

Effect of exercise on plasma kallikrein and muscular phospholipase A2 activity in rats.

Many experimental observations show that prolonged physical exercise produces an increase of muscular glucose uptake. Recent findings suggest that the kallikrein-kinin-prostaglandin system may be related to this phenomenon, but so far, no direct evidence of quantitative alteration in this system has been observed during exercise. We measured plasma kallikrein and muscular phospholipase A2 activity, respectively the first and the last steps of reactions leading to prostaglandin synthesis. We demonstrated, for the first time, that during exercise plasma kallikrein activity increases in rats. We also observed an increase of muscular phospholipase A2 activity after exercise and a positive correlation between these parameters. Our findings demonstrate, under physiological conditions of enhanced muscular glucose uptake, a concomitant significant increase of plasma kallikrein and muscular phospholipase A2 activity, supporting the hypothesis that activation of the kallikrein-kinin-prostaglandin system may play some part in the enhanced muscular glucose uptake during physical activity.

Animals↗
PubMed1985

Lack of effect of im diazepam administration on hGH and hPRL secretion in normal and acromegalic subjects.

The usefulness of diazepam as a provocative stimulus for hGH secretion has been suggested as a simple, reliable test in clinical hGH assessment of pituitary disorders. We have investigated the effects of diazepam (10 mg im) on plasma hGH and hPRL in 5 normal and 7 acromegalic subjects. No significant variations in hGH and hPRL levels have been observed in any of the studied subjects. These findings indicate that the drug is ineffective on hGH and hPRL release and that it cannot be considered a valid provocative test either in normal or acromegalic subjects.

Acromegaly↗
PubMed1985

Metabolic effects of physical training in subjects with oral glucose intolerance.

A group of normal weight subjects with oral glucose intolerance was studied for 4 months before, during, and after a physical training program (8 km/day/run). There were no significant differences in weight, basal blood glucose, lactate, and total cholesterol during and after training as compared with before training. Serum triglycerides significantly (P less than 0.05) decreased during the training period, and cholesterol-HDL significantly (P less than 0.01) increased during and after the physical program. Our data show that in previously inactive subjects with oral glucose intolerance physical training improves serum lipid patterns and thereby reduces atherosclerotic risk.

Adult↗
PubMed1984

Bioavailability of bromazepam in man after single administration of an oral solution.

The relative bioavailability of a liquid oral form of 7-bromo-1,3-dihydro-5-(2-pyridyl)-2H-1,4-benzodiazepin-2-one (bromazepam, Lexotan, Lexotanil) in comparison with the conventional oral form (capsules) was investigated. The study was performed on six healthy volunteers who were administered both the drug products in a single oral dose of 3 mg of bromazepam in a randomized cross-over trial. An additional investigation was performed on the same subjects by administering the liquid oral solution at a lower dosage: 1.5 mg in order to confirm first-order kinetics at low dosage, too. The results showed the same bioavailability for the oral forms tested and confirmed first-order kinetics for the 1.5 mg dose, too.

Administration, Oral↗
PubMed1983

Pituitary microadenomas: surgical results and morphological findings.

The results of transsphenoidal microsurgery in treating 22 patients with pituitary microadenomas are reported. Histological and ultrastructural comparative studies were performed in attempting to obtain a more accurate morphological classification of pituitary microadenomas.

Adenoma↗
PubMed1983

Plasma kallikrein activity in human diabetes mellitus.

It has recently been observed that administration of bradykinin to diabetic patients improves peripheral glucose utilization. To verify whether there is an alteration of the kallikrein-kinin system in human diabetes, plasma kallikrein activity was measured in 47 diabetic patients and in 20 control subjects. In diabetics plasma kallikrein activity was significantly higher than in controls: 1.04 +/- 0.04 U/ml (p less than 0.001). Although they do not refute the hypothesis that there is an alteration of the kallikrein-kinin system in diabetes mellitus, these findings do not support such a hypothesis either. Increased synthesis of plasma kallikrein activity may be due to increased synthesis of carbohydrate-protein compounds in diabetes mellitus.

Adult↗
PubMed1983

The acromegaly--gigantism syndrome. Report of four cases treated surgically.

Four cases of growth-hormone-secreting pituitary adenoma, with associated aspects of acromegaly and gigantism, are reported in patients aged 12-26. All of the patients had macroadenomas and were treated surgically, three by the transsphenoidal approach and one with a transfrontal craniotomy. Histologic examination revealed eosinophilic adenomas in three of the cases and a mixed eosinophilic--chromophobe adenoma in one, all with cellular irregularities (mitosis and cellular and nuclear polymorphism), local invasivity, or both. Because surgical treatment did not produce complete normalization of growth hormone levels, radiotherapy followed the operations in all four cases. In our opinion, the treatment of acromegalic gigantism poses more therapeutic problems than that of simple acromegaly, with combined treatment (surgical, radiation, and medical) often being necessary.

Acromegaly↗
PubMed1981

Plasma and urine free L-carnitine in human diabetes mellitus.

L-carnitine is essential for the transport of long-chain fatty acids into mitochondria and their oxidation. Recently, a relationship between plasma free fatty acids (FFA) and L-carnitine metabolism has been observed. Plasma free L-carnitine (FC), FFA, triglycerides, cholesterol, blood glucose concentration and daily excretion of FC were determined in 20 diabetic patients as well as in 18 control subjects. Both in male diabetics and in male controls, plasma FC was significantly higher than in females. Mean plasma FC was found to be significantly reduced in diabetics (21 +/- 2 vs 35 +/- 2 mumol/1 in non-diabetic subjects; p less than 0.005). Daily urinary excretion of FC was clearly lower in diabetic patients than in controls (172 +/- 34 vs 403 +/- 38 mumol/24 h; p less than 0.001). The reduced plasma FC in diabetes mellitus may be due to redistribution between circulating free and esterified carnitine and to increased utilization of FC for synthesis of acylcarnitine in tissues.

Blood Glucose↗
PubMed1981

Lack of effect of calcium infusion on blood glucose and plasma insulin levels in patients with insulinoma.

In vitro calcium plays a fundamental role in regulating insulin secretion. On the other hand, the influence of calcium excess on insulin release in vivo is not clearly defined. Recently, calcium infusion has been proposed as a provocative test for the diagnosis of insulin-secreting tumors. A 2-h infusion of calcium gluconate was performed (4 mg/kg . h) in six patients with islet cell adenoma. As a result, mean calcium plasma levels increased from 9.6 +/- 0.4 to 11.6 +/- 0.8 mg/100 ml. During calcium infusion, blood glucose and plasma insulin concentrations remained unchanged. These observations suggest that calcium fails to stimulate basal insulin secretion even in cases of organic hyperinsulinism. They show that calcium infusion is not helpful as a provocative test in the diagnosis of insulinoma.

Adenoma, Islet Cell↗
PubMed1978

The effect of propranolol on hypoglycaemia. Observations in five insulinoma patients.

Five hypoglycaemic hyperinsulinaemic patients (three with proven benign insulinoma, one with proven metastasizing insulinoma, one with probable insulinoma not found at surgery) were treated with propranolol for a variable time ranging from two weeks to one year. Three patients showed favourable clinical results and a significant increase of the mean basal blood glucose level was found while two patients showed no improvement of the frequency of neuroglycopenic episodes and no significant increase of their mean blood glucose level. No patient showed a significant decrease in mean basal IRI concentration. A decrease of insulinaemic responses was observed during oral and intravenous glucose tolerance tests, a prolonged fast, and tolbutamide and glucagon tests performed in some patients. The results suggest that propranolol may induce in certain patients an improvement of basal clinical status through not understood effects (probably hepatic), which leave the peripheral concentrations of insulin unchanged, whereas inhibition of insulin secretion may represent the main way by which the improvement of metabolic situation during physiological or pharmacological stimulation may have been achieved.

Adenoma, Islet Cell↗
PubMed1977

Effect of chlorpromazine on blood glucose and plasma insulin in man.

In three groups of normal subjects and in one group of patients with latent diabetes mellitus a study has been made of the effects of chlorpromazine (CPZ) on blood glucose and plasma insulin. CPZ 75 mg/day for 7 days did not alter the plasma insulin response after oral glucose; nor did CPZ 50 mg/day for 7 days affect the glucose assimilation rate or insulin response to glucose injection. Infusion of CPZ 50 mg in 60 min slightly increased the basal blood glucose level but had no significant effect on basal plasma insulin. The insulin/glucose ratio after the end of the infusion was significantly higher than during the period of infusion of the drug. In latent diabetic patients CPZ infusion significantly diminished the insulin/glucose ratio during an intravenous glucose tolerance test. These results suggest that, whereas prolonged treatment with low doses of CPZ did not modify glucose tolerance and glucose-stimulated pancreatic response, higher acute doses of the drug may induce hyperglycaemia and can inhibit insulin secretion both in normal man and in patients with latent diabetes mellitus.

Administration, Oral↗
PubMed1976

Plasma insulin response to glibornuride in thyrotoxicosis.

The glycemic and insulinemic response to i.v. glibornuride injection has been studied in a group of 8 euthyroid subjects and in a group of 9 thyrotoxic patients before and after reserpine treatment. In thyrotoxic patients sulfonylurea did not lower blood glucose more than in normal subjects. The plasma insulin response, however, was definitely higher than that of the controls in the first few minutes; after the 20th minute, however, levels of insulinemia were not appreciably different in the two groups. Insulin delivery rate was greater in hyperthyroid patients than in the controls. Administration of reserpine for a few days, did not modify either insulin response or blood glucose fall in thyrotoxic patients.

Blood Glucose↗
PubMed1976

Medical treatment of endogenous organic hyperinsulinism.

There are several situations in which medical therapy of hyperinsulinism induced by islet cell tumors or hyperplasia is necessary and at present we have at our disposal several drugs which are capable of reducing endogenous hyperinsulinism. They are: -Streptozotocin, which represents today the most useful therapeutic agent for beta cell carcinoma therapy; -Diazoxide, which represents the drug of first choice for the treatment of most hypoglycemic syndromes caused by islet cell adenoma or hyperplasia; -Propranolol, Chlorpromazine, Diphenylhydantoin, which may be regarded as a useful alternative to diazoxide, although they are capable of giving rather inconstant results. These drugs may today effectively substitute for corticosteroids and glucagon in the medical treatment of almost every chronic hyperinsulinemic hypoglycemic syndrome, including malignant beta cell carcinoma.

Adenoma, Islet Cell↗
PubMed1975

Role of growth hormone in lipid mobilization stimulated by prolonged muscular exercise in the rat.

The effects of prolonged muscular exercise (swim in tepid water for 60 min) on blood glucose, plasma FFA and R-GH were studied in a group of normal rats and the effect on blood glucose and plasma FFA in a group of hypophysectomized rats. The data obtained showed that, whereas in normal rats plasma FFA rose after muscular exercise, plasma R-GH fell sharply. In Hypophysectomized rats, however, muscular exercise did not increase plasma FFA levels.

Animals↗