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Biomedical subjects

F Meschi

Publications and source records attributed to F Meschi.

At least 55 records · Page 3Linked to original sources

Insulin resistance in a child with Acanthosis nigricans type A.

The patient, a female 6 years 4 months old, diagnosed as affected by Acanthosis nigricans and diabetes mellitus was referred to our Clinic for further investigation of her glucose metabolism. She had a typical face with hypertelorism, prognathism, macroglossia and large auricles. The skin was hyperpigmented, verrucous, hyperkeratotic especially in the folds and flexural areas with small papillomatous or nodular growth; diffused hypertrichosis and hypertrophic clitoris were also present. Biochemical and hormonal investigations revealed no major abnormalities apart from glucose metabolism. After an unsuccessful trial with conventional insulin therapy, endovenous continuous insulin infusion was started: even with 32 U/kg/h it was not possible to achieve normoglycemia. Insulin receptors were studied on erythrocytes: 125I-insulin binding (specific) was clearly lower than normal. The concentration of insulin receptors was reduced, while the average affinity profile was normal. The study of erythrocyte insulin receptors has demonstrated that insulin resistance in this patient is due to a decrease in the number of receptors, i.e. Acanthosis nigricans type A.

Acanthosis Nigricans↗

Pancreatic endocrine function in leukemic children treated with L-asparaginase.

The effect of arginine infusion on blood glucose and plasma levels of insulin, C-peptide and glucagon has been studied in leukemic children before and after treatment with L-asparaginase (10,000 U/m2/day for 10 days). Therapy induced a significant reduction in basal and peak blood glucose, insulin and C-peptide levels, while glucagon was unmodified. The conserved C-peptide-insulin molar ratio suggests the interference of L-asparaginase with proinsulin synthesis. In conclusion our results prove a decreased insulin reserve with a preserved, although reduced, beta-cell function.

Asparaginase↗

C-peptide response to arginine stimulation in diabetic children.

The extent and the clinical significance of residual beta cell function has been evaluated by radioimmunoassay of C-peptide in 41 diabetic children in different stages of evolution, using an arginine tolerance test. In control subjects a significant rise of C-peptide levels occurred after the infusion with arginine. In patients at the onset of the disease and in patients not in the remission stage, C-peptide levels showed no increment and basal values were significantly lower than in healthy control children. Children during the remission phase showed basal and peak values not significantly different from controls. A positive correlation was found between highest CPR levels compared to basal CPR values and to the age at onset of diabetes; a negative correlation was found between the duration of the disease and insulin requirement.

Arginine↗

Glucagon response to arginine stimulation in obese and diabetic children.

The effect of arginine infusion on blood sugar and plasma levels of growth hormone and glucagon has been studied in children with clinical diabetes mellitus and in obese children with normal carbohydrate tolerance. Basal levels of plasma GH are significantly lower in obese children than in diabetics and controls; in obese subjects the increment of GH is significantly lower than in diabetics and controls. Basal plasma glucagon levels are comparable in all three groups despite the high sugar levels in diabetic patients. After arginine infusion there is a significant rise in glucagon levels without significant differences between the three groups.

Adolescent↗

Genetic prediction of type 1 diabetes in a population with low frequency of HLA risk genotypes and low incidence of the disease (the DIABFIN study).

BACKGROUND: To develop a sensitive, specific screening strategy for predicting genetic risk for type 1 diabetes mellitus (T1DM) in the low-incidence continental Italian population, and to define with this tool, a cohort of high-to-moderate risk infants for an immunological follow-up study aimed at identifying environmental risk factors for T1DM. METHODS: 4855 newborns in three regions of continental Italy were screened for T1DM HLA-DRB1-DQB1 risk genotypes using a reverse line blot typing method. Risk classification was based on odds ratios (OR) found in a preliminary case-control study (356 T1DM patients, 412 controls). Screening efficiency was optimized by allele subtyping. RESULTS: Screening for well-known T1DM susceptibility genotypes [DRB1*03/*04-DQB1*0302; DRB1*03/*03; DRB1*04/*04-DQB1*0302; DRB1*04-DQB1*0302/X where X is not equal to DRB1*03, DRB1*04-DQB1*0302, DQB1*0602 or DQB1*0603] was associated with <60% sensitivity due to their low frequencies in the general Italian population. Inclusion of an additional genotype from which protective DRB1 and DQB1 alleles had been excluded [DRB1*03/X degrees where DQB1 is not equal to *0301, *0503, *0602, or *0603 and X degrees not equal DRB1*03, DRB1*04-DQB1*0302 or DRB1*07] increased screening sensitivity to 75% (specificity: 85%). Among 4855 newborns, we have found the high-risk genotype [DRB1*03/*04-DQB1*0302; estimated absolute risk (AR) 1/23] to be present in only 0.9%. The moderate-risk genotypes were found in 13.8% of newborns (estimated AR 1/177). CONCLUSIONS: Risk classification must be tailored to the characteristics of the individual population, in particular, the allelic frequencies in the background population and T1DM prevalence. We have developed a screening strategy with good levels of sensitivity that should prove effective for use throughout the Italian peninsula.

Adult↗

Pancreatic polypeptide secretion after insulin infusion and protein meal in juvenile type 1 diabetic subjects.

An impaired pancreatic polypeptide response (PP) after hypoglycemia has been described in type I diabetic patients with overt autonomic neuropathy. Some authors have suggested that PP release might be useful as sensitive indicator of autonomic neuropathy. The meal test is safer and simpler than the insulin infusion test as PP stimulus. The aim of this study was to compare PP response to insulin infusion and protein meal test and to correlate these responses to the presence of measurable neuropathic disturbances. We thus studied 13 IDDM children and adolescents and 6 normal children. In diabetics the PP response to both tests was not different from that of the control subjects, but PP response to insulin infusion was inversely correlated to the duration of illness and was significantly lower in subjects with pathological heart rate response when compared to the control group. PP responses to the two stimuli were not correlated. We suggest that reduced PP response to hypoglycemia is an early sign of autonomic neuropathy as well as impairment of beat-to-beat variation when impaired PP response to meal test is still not evident.

Adolescent↗

Peripheral nerve abnormalities in newly-diagnosed diabetic children.

The prevalence of clinical and subclinical peripheral neuropathy was evaluated in 51 unselected children at the time of onset of type I diabetes. Twenty-eight patients were followed for one year in order to establish the influence of metabolic control on peripheral nerve function. Twenty-two % of the diabetic children showed nerve conduction abnormalities at the onset and 11.7% had clinical features of peripheral neuropathy. After one year of disease, these figures had changed to 14.3% and 7.1%. Five of 7 children with altered electrophysiological tests in the baseline assessment had had normalization of all parameters one year later. No correlations between insulin requirement and nerve conduction were found. The M value was significantly correlated only with median sensory conduction velocity (p less than 0.005). Significant correlations were demonstrated between HbA1 concentration and both peroneal motor conduction velocity (p less than 0.025) and median sensory conduction velocity (p less than 0.005); these correlations were still present after one year of disease. In the first period of diabetic disease there is functional rather than structural damage of the nerves. The pathogenetic role of hyperglycemia is confirmed; however individual susceptibility to nerve dysfunction may play an important role in the nerve impairment in diabetes.

Adolescent↗

Relationship between metabolic control and HDL2-cholesterol in type I diabetic patients.

The relationship of the degree of metabolic control to the serum lipoprotein pattern has been studied in 62 young insulin treated diabetic patients. Stable HbA1 and 24-h mean blood glucose, but not daily insulin dosage, were positively correlated to VLDL-TG (p less than 0.001) and negatively correlated to HDL2-C (p less than 0.05). HDL2-C was higher in patients with HbA1 less than 10% than in patients with HbA1 greater than 10%. In 13 patients, in whom an improvement of metabolic control was achieved, a significant increase of HDL2-C was recorded after three months. Our data are consistent with the view that in insulin-treated patients, good metabolic control is associated with low VLDL-TG and high HDL2-C levels.

Adolescent↗

Short-term subcutaneous insulin infusion in diabetic children. Comparison with three daily insulin injections.

Sixteen insulin-dependent diabetic children and adolescents were studied on intensified insulin treatment (3II) and during continuous subcutaneous insulin infusion (CSII). Mean blood glucose, M-value and 24-h glycosuria were similar in both types of treatment. Symptomatic hypoglycemia occurred more often in patients on 3II than CSII. With 3II we observed blood glucose peaks early in the morning confirming that better overnight control can be achieved by CSII.

Adolescent↗

Evaluation of central nervous conduction by visual evoked potentials in insulin-dependent diabetic children. Metabolic and clinical correlations.

Peripheral neuropathy is a well-known complication of diabetes, but few data are available on central lesions. Visual evoked potentials (VEPs) seem a reliable and feasible technique for detecting a conduction delay in the central nervous system. Seventy-one insulin-dependent type 1 diabetic children (mean age 15 +/- 3 years) and 33 controls were investigated for central neuropathy. We used a pattern of reversal stimulation with television display of a checker board pattern (15 min and 30 min check size). The latencies of the positive peak (P100 wave) were significantly lengthened in 17 patients (27%) but no correlation was found between VEPs and age, duration of diabetes, insulin requirement and HbA1 level. A negative correlation was found between VEPs and peripheral nervous conduction velocity. VEPs measurement seems a simple and reliable technique for detecting early alterations in CNS function in diabetics. Our data suggest that central and peripheral nervous alterations progress simultaneously.

Adolescent↗

The objective assessment of visual contrast sensitivity by pattern reversal visual evoked potentials in diabetes.

Recent studies have described abnormalities of visual evoked potentials and pattern electroretinography in diabetics without retinopathy. The visual contrast sensitivity, determined by psychophysical tests, has proved to be abnormal in diabetic patients with and without clinical retinopathy. In this study we evaluated contrast sensitivity function using both electrophysiologic and psychophysical methods. The objective assessment of functional visual contrast sensitivity was superior to psychophysical evaluation in the detection of contrast sensitivity alterations. No relationships were found between contrast sensitivity dysfunction and abnormalities of pattern electroretinography or fluorescein angiography. Our data suggest that functional visual deficits might precede background retinopathy and that the involvement of foveal function is early and very frequent in diabetic patients, even if they have normal visual acuity.

Adolescent↗

Cardiovascular and hormonal responses to cold pressor test in insulin-dependent diabetic adolescents with microalbuminuria.

Cardiovascular responses to cold pressor test and associated changes in blood concentrations of renin, aldosterone, and catecholamines were measured in 11 type I diabetic patients with microalbuminuria; 11 type I diabetic patients with normoalbuminuria matched for age, duration of diabetes, metabolic control; and in nine normal control subjects. Heart rate, renin, aldosterone, and catecholamines concentrations in diabetic patients and controls at baseline were similar, but higher mean blood pressure was evident in microalbuminuric than normoalbuminuric patients (p < 0.01) and controls (p < 0.05). Heart rate and mean blood pressure during cold pressor test in control subjects and type I diabetic patients increased significantly but similarly, regardless of the presence of microalbuminuria. Catecholamines, but not renin-aldosterone release, was associated to blood pressure modifications during the test. Peak values of mean blood pressure induced by cold test were positively correlated to baseline values in control subjects (r = 0.658, p < 0.05) and normoalbuminuric (r = 0.725, p < 0.01), but not microalbuminuric diabetics. These data suggest that the higher blood-pressure values at rest observed in microalbuminuric than normoalbuminuric diabetics are not associated with a higher cardiovascular response to cold hypertensive stimulus.

Adolescent↗

Prevalence and correlations of early microvascular complications in young type I diabetic patients: role of puberty.

The prevalence and correlates of the early signs of renal, retinal and neurological microvascular complications were evaluated in 317 young patients with type I diabetes mellitus. Microalbuminuria was detected in 11% of patients and appeared to be strongly and positively related to HbA1c (p < 0.01) and less significantly to duration of diabetes (p < 0.02). Retinopathy was detected in 22.7% of patients and it was associated with duration of diabetes (p < 0.001). Peripheral neuropathy was detected in 18.5% of patients and there was a strong association with HbA1c (p < 0.01) and a weaker one with duration of diabetes (p < 0.05). Microalbuminuria was not detected in prepubertal patients while a similar frequency of retinopathy and neuropathy was observed in prepubertal and postpubertal patients. These results suggest that: 1) In short-term type I diabetic patients neuropathy is the most frequent microvascular complication, but after 10 years of diabetes, retinopathy exceeds the other complications; 2) Short-term metabolic control may influence the frequency of neuropathy and microalbuminuria but not retinopathy; 3) Puberty is involved in the appearance of microalbuminuria.

Adolescent↗

Prednisone treatment in newly diagnosed type I diabetic children: 1-yr follow-up.

Thirty-one children suffering from type I diabetes mellitus were arranged at onset of the disease in two different groups. Group 1 was treated with oral prednisone (60 mg X m-2 X day-1 for 14 days, 30 and 15 mg X m-2 X day-1 for 7 days). Group 2 matched the control group. All patients were treated with continuous subcutaneous insulin infusion for the first 15 days of treatment, and then with two daily injections of a mixture of intermediate- and fast-acting insulin. All subjects were followed for 1 yr. Group 1 required more insulin than group 2 after 30 days (1.5 +/- 0.3 vs. 0.6 $ 0.2 U X kg-1 X day-1, P less than .001) and after 60 days (0.8 +/- 0.1 vs. 0.5 +/- 0.06 U X kg-1 X day-1, P less than .001). After 3 mo, both groups reached the lowest mean stable HbA1 level (8.4 +/- 0.4 and 8.3 +/- 0.4% group 1 and 2 respectively). Between the 2nd and 9th mo of follow-up, mean postbreakfast C-peptide concentration increased in both groups. The highest levels of fasting C-peptide were reached by group 1 after 90 days (0.77 +/- 0.32 nM) and group 2 after 60 days (0.34 +/- 0.09 nM). The largest partial remission (C-peptide 0.3 nM, insulin requirement less than 0.5 U X kg-1 X day-1 and no glycosuria) was observed in group 1 after 180 days (5 of 16 patients) and in group 2 after 60 days (5 of 15 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗