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Biomedical subjects

L Beccaria

Publications and source records attributed to L Beccaria.

At least 37 records · Page 2Linked to original sources
PubMed1988

Physiological role for cholecystokinin in reducing postprandial hyperglycemia in humans.

It is known that the ingestion of glucose alone causes a greater increase in plasma glucose levels than ingestion of the same amount of glucose given with other nutrients. Since physiological plasma concentrations of cholecystokinin (CCK) prolong gastric emptying, it is proposed that after a meal, CCK may modify plasma glucose levels by delaying glucose delivery to the duodenum. To evaluate the effect of CCK on oral glucose tolerance, plasma CCK, insulin, and glucose levels and gastric emptying rates were measured in eight normal males before and after the ingestion of 60 g glucose with the simultaneous infusion of either saline or one of two doses of CCK-8 (12 or 24 pmol/kg per h). Gastric emptying rates were measured by gamma camera scintigraphy of technetium 99m sulfur colloid and plasma CCK levels were measured by a sensitive and specific bioassay. Basal CCK levels averaged 1.0 +/- 0.1 pM (mean +/- SEM, n = 8) and increased to 7.1 +/- 1.1 pM after a mixed liquid meal. After glucose ingestion, but without CCK infusion, CCK levels did not change from basal, and the gastric emptying t1/2 was 68 +/- 3 min. Plasma glucose levels increased from basal levels of 91 +/- 3.9 mg/dl to peak levels of 162 +/- 11 mg/dl and insulin levels increased from 10.7 +/- 1.8 microU/ml to peak levels of 58 +/- 11 microU/ml. After glucose ingestion, with CCK infused at 24 pmol/kg per h, plasma CCK levels increased to 8 pM and the gastric emptying t1/2 increased to 148 +/- 16 min. In concert with this delay in gastric emptying, peak glucose levels rose to only 129 +/- 17 mg% and peak insulin levels rose to only 24.2 +/- 4.2 microU/ml. With CCK at 12 pmol/kg per h, similar but less dramatic changes were seen. To demonstrate that endogenous CCK could modify the plasma glucose and insulin responses to oral glucose, oral glucose was given with 50 g of lipid containing long-chain triglycerides. This lipid increased peak CCK levels to 3.7 +/- 0.9 pM. Concomitant with this rise in CCK was a delay in gastric emptying and a lowering of plasma glucose and insulin values. To confirm that CCK reduced hyperglycemia by its effect on gastric motility, 36 g glucose was perfused directly into the duodenum through a nasal-duodenal feeding tube in four subjects. With duodenal perfusion of glucose, there was no change in plasma CCK levels, but plasma glucose levels increased from basal levels of 93+/-5 to 148+/-6 mg/dl and insulin levels rose from 10.6+/-3.5 to 29.5+/-5.2 microU/ml. When CCK was infused at 24 pmol/kg per h, neither the plasma glucose nor insulin responses to the duodenal administration of glucose were modified. Thus we conclude that CCK, in physiological concentrations, delays gastric emptying, slows the delivery of glucose to the duodenum, and reduces postprandial hyperglycemia. These data indicate, therefore, that CCK has a significant role in regulating glucose homeostasis in human.

Administration, Oral↗
PubMed1986

Visual evoked potentials in diabetic teen-agers: influence of metabolic control and relationship with peripheral neuropathy.

85 type 1 diabetics aged between 8 and 20 years (mean: 15.06) performed Pattern Reversal Visual Evoked Potentials (PRVEP). In addition all of them were investigated for peripheral neuropathy and 63 subjects for retinopathy. Our study disclosed a subclinical involvement of optic nerve pathways in about 1/4 of diabetic teen-agers. P100 mean latency was delayed in diabetics for both 30' (112.8 +/- 7.7 msec versus 109.1 +/- 4.8 msec) and 15' check size (119.1 +/- 10.5 msec versus 112.8 +/- 5.2 msec). The N75-N140 interpeak latency was also significantly delayed and the mean N75-P100 amplitude was significantly reduced in diabetics. No correlation was found between PRVEPs latency and age, HbA1, and insulin requirement. The mean P100 latency significantly increased with the duration of diabetes. A negative correlation was found at the 30' check size between P100 latency and motor and sensory conduction velocity in all the examined nerves. 10 out of 63 patients, who had been examined with fluorangiography, showed abnormalities; only 2 of these 10 subjects had abnormal PRVEP. The association of prolonged P100 latency, prolonged N75-N140 interpeak latency and reduced N75-P100 amplitude can be considered consequent to a desincronisation of the impulses travelling along the optic pathways.

Adolescent↗
PubMed1984

Metabolic control in newly diagnosed type 1 diabetic children. Effect of continuous subcutaneous infusion.

15 insulin-dependent diabetic children at onset were randomly allocated to one of two different therapeutical protocols: continuous subcutaneous insulin infusion (CSII) and intensified conventional insulin treatment with three daily insulin injections (CIT). Both treatments were performed for 10 days; the initial insulin dose was 1.5 U/kg/day and thereafter the insulin dosage was modified in order to obtain a satisfactory control. Near-normal blood glucose levels were obtained after 24 h in the CSII group, and after 3 days in the CIT group. All subjects underwent 1 year of follow-up. HbA1 levels and insulin requirements decreased similarly in the two groups; C-peptide secretion did not increase significantly in both groups. A clear advantage of CSII cannot be assumed, and the usefulness of this therapeutical approach needs to be confirmed by further investigations.

Adolescent↗
PubMed1978

Hemoglobin A1C separation by isoelectric focusing.

A modified type of isolectric focusing has been applied successfully to the separation of hemoglobin A1C (HbA1C) from HbA in normal and diabetic cell lysates. It consists of transforming a linear pH gradient into a nonlinear one, by the addition of an amphoteric substance ("separator" or "pH gradient modifier") with an isoelectric point (pI) close to the pI's of the two hemoglobins. Among the "modifiers" tested, histidine, proline, threonine, beta-alanine, 6-amino caproic acid, and 5-amino valeric acid are not useful in the hemoglobin pI range (pH 6.9--7.0). The dipeptide histidyl-glycine (pI = 6.8; pI-pK1 = 1) is very efficient in flattening the pH gradient, in the hemoglobin region. even when added in low concentrations (10--100 mM), thus affording full resolution of the two hemoglobin species.

Alanine↗
PubMedDate not supplied

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↗
PubMedDate not supplied

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↗
PubMedDate not supplied

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↗
PubMedDate not supplied

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↗
PubMedDate not supplied

Further evidence of cholinergic impairment of the neuroendocrine control of the GH secretion in Down's syndrome.

There are data indicating that cholinergic activity is precociously impaired in Down's syndrome (DS). On the other hand, acetylcholine as well as arginine (ARG) play a major stimulatory role in the neural control of growth hormone (GH) secretion in humans, likely acting via the inhibition of hypothalamic somatostatin release. The aim of the present study was to verify the effects of pyridostigmine (PD, 120 mg p.o.), a cholinesterase inhibitor, and ARG (0.5 g/kg i.v.) on the growth hormone-releasing hormone (GHRH) (1 microgram/kg i.v.)-induced GH rise in 15 adult patients with DS (M/F: 8/7; age 26.5 +/- 2.2 years; body mass index, BMI: 25.7 +/- 1.0 kg/m2) in which the potentiating effect of PD on GH secretion has been reported to be reduced. The results in DS were compared to those in 15 normal subjects (NS) (M/F: 8/7; age: 30.0 +/- 1.3 years; BMI: 21.4 +/- 0.4 kg/m2). Basal GH and insulin growth factor I (IGF-1) levels in DS (1.8 +/- 0.7 and 206.5 +/- 21.0 micrograms/l) were similar to those in NS (1.4 +/- 0.3 and 179.4 +/- 11.0 micrograms/l). The GH response to GHRH alone in DS (526.5 +/- 120.1 micrograms/l/h) was lower (p < 0.05) than that recorded in NS (895.4 +/- 153.7 micrograms/l/h). The GHRH-induced GH rise was potentiated by PD both in DS (1,138 +/- 184.2 micrograms/l/h; p < 0.02 vs. GHRH alone) and in NS (2,213.8 +/- 212.8 micrograms/l/h; p < 0.005 vs. GHRH alone); however, as the percent potentiating effect of PD was similar in both groups (215 and 247%, respectively) the GH response to GHRH + PD in DS was lower (p < 0.005) than that in NS. The GHRH-induced GH rise was also potentiated by ARG in both DS (2,243 +/- 362.4 micrograms/h; p < 0.001 vs. GHRH alone) and NS (2,764.3 +/- 325.7 micrograms/l/h; p < 0.005 vs. GHRH alone). As the percent potentiating effect of ARG in DS was more marked than in NS (425 vs. 308%, respectively), the GH response to GHRH + ARG became similar in both groups. No sex-related difference was found in the GH response to various stimuli both in DS and NS. In conclusion, these data demonstrate that the potentiating effect of PD but not that of ARG is impaired in adults with DS in whom a reduced somatotrope responsiveness to GHRH is present. These findings indicate that in DS the pituitary GH releasable pool is fully preserved while an impairment of the tuberoinfundibular cholinergic pathways could lead to somatostatinergic hyperactivity and low somatotrope responsiveness to GHRH.

Acetylcholine↗
PubMedDate not supplied

GH secretion in Prader-Labhard-Willi syndrome: somatotrope responsiveness to GHRH is enhanced by arginine but not by pyridostigmine.

Low somatotrope responsiveness to secretagogues has been reported in patients affected by Prader-Labhard-Willi Syndrome (PLWS). In normal subjects, GH response to GHRH is known to be greatly potentiated to the same extent by pyridostigmine (PD) or arginine (ARG) which probably act via inhibition of hypothalamic somatostatin release. To clarify somatotrope responsiveness in 7 PLWS patients, we studied GH response to GHRH alone and to GHRH combined with PD or ARG. Eight normal short children were studied as controls (NC). GH response to GHRH in PLWS was lower than in NC (AUC: 615 +/- 205 micrograms/l.h, vs 1271 +/- 333 micrograms/l.h, p < 0.02). In NC, the GHRH-induced GH rise was potentiated to the same extent by PD or ARG. In contrast, in PLWS PD failed to increase the GH response to GHRH (AUC: 615 +/- 205 micrograms/l.h vs 621 +/- 176 micrograms/l.h, n.s.) which was enhanced by ARG (AUC: 615 +/- 205 micrograms/l.h vs 1633 +/- 425 micrograms/l.h, p < 0.02). However, the GH response to GHRH + ARG in PLWS was lower than in NC. In conclusion, our results demonstrate that in PLWS the low somatotrope responsiveness to GHRH is not enhanced by cholinergic potentiation while it is increased by arginine.

Adolescent↗
PubMedDate not supplied

Multiple insulinomas of the pancreas: a patient report.

Whereas there is general agreement about the biochemical diagnosis of hyperinsulinism, the value of imaging to differentiate diffuse from focal pancreatic lesions is still a matter of debate. We describe a case of multiple adenomas of the pancreas in an eleven year-old boy. The source of hyperinsulinism was detected by pancreatic ultrasound examination and confirmed by MRI as a single adenoma of the pancreas. These radiological exams did not identify three other pancreatic adenomata. Our report outlines the difficulties in anatomically localizing the source of excessive insulin secretion in cases of hyperinsulinemic hypoglycemia.

Blood Glucose↗
PubMedDate not supplied

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↗