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Biomedical subjects

G Lenti

Publications and source records attributed to G Lenti.

At least 19 recordsLinked to original sources
PubMed1991

[Treatment of juvenile chronic arthritis].

The treatment of juvenile chronic arthritis requires the integration of various professionals (pediatrician, physiotherapist, orthopedic surgeon, ophthalmologist). The therapeutic program is targeted to control the inflammation with drugs and to preserve joint function with physiotherapy. Since juvenile chronic arthritis is clinically heterogeneous, the natural course and the possible complications which characterize each clinical form must be taken into account.

Adolescent↗
PubMed1989

The hyperlactatemic effect of biguanides: a comparison between phenformin and metformin during a 6-month treatment.

To compare the chronic hyperlactatemic effect of phenformin and metformin, we performed a double-blind study in 10 non insulin-dependent diabetics without any other known hyperlactatemic condition. After a pre-study period, each patient was allocated to a 6-month treatment with phenformin (50 mg bid) or metformin (850 mg bid) in random sequence. Body weight values were not significantly different between phenformin and metformin. Diabetic control was significantly (p less than 0.001) improved by both biguanides versus pre-study, but was the same during metformin and phenformin: HbAI = 13.8 +/- 0.3 SEM% during pre-study 9.7 +/- 0.2% during phenformin, 10.2 +/- 0.2% during metformin. Mean values of plasma lactate during metformin were significantly lower versus phenformin (1.30 +/- 0.05 vs 1.64 +/- 0.05 mmol/l, p less than 0.001). Mean values of plasma lactate/pyruvate ratio during metformin were significantly lower versus phenformin (16.92 +/- 0.59 vs 22.65 +/- 0.87, p less than 0.001), but not versus pre-study (16.19 +/- 0.51). These results indicate that: 1) during a 6-month treatment with a diabetic control of similar degree phenformin produces a significantly higher hyperlactatemic effect vs metformin; 2) metformin treatment is associated with less impairment of intracellular redox state versus phenformin, and therefore should be considered advantageous in the long-term treatment of non insulin-dependent diabetics.

Acidosis, Lactic↗
PubMed1988

Insulin resistance in Graves' disease: a quantitative in-vivo evaluation.

Hyperthyroidism is considered to be an insulin-resistant state, but a quantitative evaluation of some action of insulin is still lacking. We performed euglycaemic clamp at about 350 and 7000 pmol l-1 plasma insulin concentration in combination with the 3H-glucose infusion in 12 patients with Graves' disease and in 12 matched controls. Fasting plasma insulin (126 +/- 6.5 vs. 77.5 +/- 5.7 pmol l-1; P less than 0.001), C-peptide (502 +/- 36 vs. 363 +/- 41 pmol l-1; P less than 0.001) and glucagon (47 +/- 3.3 vs. 33.3 +/- 3 pmol l-1; P less than 0.01) were significantly higher in hyperthyroids than in euthyroids. Basal hepatic glucose production was significantly higher in hyperthyroids than in euthyroids (18.3 +/- 1.4 vs. 9.2 +/- 0.5 mumol l-1; P less than 0.0001), and its suppression during physiological hyperinsulinaemia was only 50% in hyperthyroids. Glucose utilization and suppression of lipolysis were normally stimulated by insulin. All parameters altered during hyperthyroidism were normalized during methimazole-induced euthyroidism. We conclude that insulin resistance involves mainly glucose rather than lipid and is selective at the hepatic level.

Adult↗
PubMed1987

Genetic, immunologic, and environmental heterogeneity of IDDM. Incidence and 12-mo follow-up of an Italian population.

The 1-yr incidence of insulin-dependent diabetes mellitus (IDDM) in a population of the Piedmont and Aosta Valley area of Italy was recorded. Anti-virus antibodies (e.g., Coxsackie B1-6, mumps, cytomegalovirus), islet cell antibodies (ICAs), and HLA-A, -B, -C, and -DR were determined in 74 IDDM patients (38 males, 36 females) and in controls. Total IDDM incidence was 5.0/100,000, and the incidence for those less than 20 yr of age was 11.6/100,000. Anti-virus antibody frequency was not different in IDDM patients and controls. ICAs were present in 58% of IDDM patients at onset and in 30% after 12 mo, and complement-fixing ICAs were found in 39 and 17%, respectively. IDDM was significantly and positively associated with DR3/DR4 and negatively associated with DR2 and DR5. ICA frequency was significantly higher in DR3/DR4 heterozygote patients than in patients without DR3 and DR4. These results suggest that in this IDDM population viral etiology is not evident, ICAs offer only a partial pathogenetic explanation, and genetic and immunologic heterogeneity is evident.

Adolescent↗
PubMed1986

Feedback inhibition of insulin secretion is altered in cirrhosis.

Hyperinsulinemia in human cirrhosis is generally considered an expression of reduced hepatic insulin degradation. To determine whether hyperinsulinemia may also depend on an altered feedback inhibition of insulin secretion, we performed euglycemic hyperinsulinemic clamp studies, infusing 40, 372, or 1280 mU/m2 X min biosynthetic human insulin in 30 compensated cirrhotic patients with portal hypertension and impaired glucose tolerance and 25 normal subjects, matched for age, sex, and weight. Mean fasting plasma insulin was significantly higher in cirrhotic patients [26.1 +/- 2.3 vs. 12.4 +/- 0.6 (+/- SE) microU/ml; P less than 0.001], while fasting plasma glucose levels were similar in the 2 groups. The mean plasma C-peptide level was significantly higher in cirrhotic patients, both basally (2.7 +/- 0.1 vs. 1.7 +/- 0.1 ng/ml; P less than 0.001) and during the clamp studies. Suppression of C-peptide at 120 min of the clamp was significantly less in cirrhotic patients (37 +/- 7% vs. 79 +/- 4%, 52 +/- 9% vs. approximately 100%, and 54 +/- 4% vs. approximately 100% during the 40, 372, and 1280 mU/m2 X min insulin infusions, respectively). The fasting C-peptide to insulin molar ratio was significantly lower in cirrhotic patients (5.4 +/- 0.3 vs. 6.4 +/- 0.3; P less than 0.005). The MCR of insulin at the three steady states was not significantly different between the 2 groups, whereas the basal systemic delivery rate of insulin was significantly higher in cirrhotic patients (14.7 +/- 1.7 vs. 6.5 +/- 0.4 mU/m2 X min; P less than 0.001). These results suggest that reduced feedback inhibition of insulin secretion may contribute to the hyperinsulinemia associated with cirrhosis.

Adult↗
PubMed1984

[Infectious endocarditis. Current aspects of its epidemiology and occurrence].

In epidemiological terms the frequency of infectious endocarditis is constant. In contrast acute forms in males and old people are on the increase. Atypical cases are more frequent than in the past so that prompt diagnosis is often difficult. Aetiologically, mycete and gram-negative cases are increasingly common.

Adult↗
PubMed1983

Exercise-induced changes of Factor VIII complex in healthy subjects and in type-I diabetics: relation between growth hormone and Von Willebrand Factor increments.

This work aims to study the exercise-induced changes of Factor VIII Complex both in healthy subjects and in type I diabetics without vascular complications, and to investigate the possible relations between growth hormone and Von Willebrand's Factor response to exercise. Results show that maximal exercise performed by cycle ergometer causes a significant increment of the procoagulant subunit (VIII:C) and of Von Willebrand Factor (VIII:RiCoF) both in healthy controls and in type I diabetics, whereas a slight increment of Factor VIII-Related antigen (VIIIR:Ag) is observed only in diabetics. The shape of the mean GH response to exercise parallels the one of Von Willebrand's Factor: however, the presence of VIII:RiCoF increments also in GH non-responders supports the conclusion that growth hormone is not the only factor involved in the regulation of Von Willebrand's Factor exercise-induced increase.

Adult↗
PubMed1983

Insulin binding to isolated monocytes and adipocytes in the study of hypoglycemic subjects and in the follow-up of patients with insulinoma.

The present study was performed to see whether insulin receptor evaluation is useful as a diagnostic tool in the differential diagnosis of hypoglycemia. The receptor numbers and affinity constants of insulin binding to adipocytes isolated from subcutaneous tissue were determined in 5 metabolically healthy subjects, undergoing laparatomy for cholecystectomy, and in 4 patients undergoing surgery for insulinoma removal. The specific insulin binding to monocytes at physiological concentrations (1 ng/ml) was also determined in all these subjects, and in 6 patients with functional hypoglycemia. The study was repeated in insulinoma patients 7 days after surgery. Results show that insulinoma patients before tumor removal have greater than 50% fall in binding capacity on both monocytes and fat cells, in keeping with the down-regulation mechanism, whereas the values for patients with functional hypoglycemia are in the normal range. After surgery, the insulin binding to monocytes sharply increased, nearly to the lower level of the normal range when the insulinoma was removed; no change was observed when the tumor was not resected (case 3). Insulin receptor study may therefore be of diagnostic and prognostic assistance in the investigation of hypoglycemic syndromes.

Adenoma, Islet Cell↗
PubMed1983

[Changes in erythrocyte deformability following changes in oxido-reductive metabolism in diabetes mellitus].

The enhanced sorbitol synthesis in diabetic red blood cells can lead to a depletion of NADPH and, by limiting the amount of GSH produced in the glutathione-reductase step, can make the cell more susceptible to oxidant injury. Diabetic red blood cells have a shortened life span, as shown by the increase of creatine level. The osmotic resistance of diabetic erythrocytes was measured and the erythrocyte flexibility was studied using a filtration method in which the cells were forced, at a constant flow rate, through a polycarbonate membrane with 5-mu pores. The increased osmotic resistance and the impaired flexibility shown by diabetic red blood cells can be induced in normal cells by a treatment with SH-reagents (diamide). This points to a redox state-mediated decrease in deformability and survival of diabetic erythrocytes.

Adult↗
PubMed1981

Insulin resistance in the aged: the role of the peripheral insulin receptors.

In the healthy subject, glucose tolerance tends to decrease with age due to impaired insulin secretion and/or decreased peripheral insulin activity. An oral glucose (100 g) tolerance test was performed on 12 aged (70 +/- 4 yr) and 8 young (32 +/- 7 yr) subjects; these subjects underwent laparatomy for cholecystectomy or the management of abdominal diseases. Subcutaneous adipose tissue was removed during surgery and fat cells, prepared according to a personal modification of Rodbell's method, were incubated in a medium containing monoiodo- and cold insulin to evaluate insulin binding and affinity constants. The results of the tolerance test pointed to an insulin resistant state i.e., impaired glucose tolerance coupled with normal plasma insulin, as previously shown also by us using other methods in the aged subject. The binding study demonstrates a distinct insulin receptor decrease in fat cells from the older subjects (185,000 +/- 19,200 as opposed to 310,000 +/- 12,000), without any change in affinity constants. The result indicates that insulin resistance in the aged may be attributed at least in part to a reduction in the number of insulin receptors on the target cells. This could be a consequence of aging itself, as proposed by other workers in the case of old fat rats.

Adipose Tissue↗
PubMed1980

[Prophylactic and therapeutic use of vitamins in diabetes (author's transl)].

The hypothesis that diabetes mellitus is a syndrome has been confirmed by recent physiopathological studies. In idiopathic diabetes differences in the genetic status and in the alternations of the beta cells allow to identify two completely different diseases: type 1 (or juvenile) diabetes and type II (or adult) diabetes. On the basis of the differences in the physiopathology of the different types of diabetes, the usefulness of vitamin supplementation for prophylaxis and therapy is discussed. The nutritional intake of thiamine is, for instance, recommended for patients suffering from the type II disease. Riboflavin deficiency has recently been observed in rat experimental diabetes as well as in human type II diabetes; the vitamin deficiency seems to be relevant in connection with functional alterations of pancreatic beta-cells. Other water-soluble vitamins are known to be involved in the pathogenesis and evolution of diabetes mellitus. Among the fat-soluble vitamins, retinol ought to be mentioned because of its importance in the mechanism of synthesis of pre-collagen and in view of the alterations in collagen and glycoprotein synthesis which accompany diabetes. Moreover, a diminished secretion of insulin has been described together with vitamins deficiences. The critical analysis of these data enables the diabetologist to define a reliable program for the prophylaxis and treatment of different kinds of diabetes.

Avitaminosis↗
PubMed1978

[Diabetic disease].

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Diabetes Mellitus↗