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Biomedical subjects

R Navalesi

Publications and source records attributed to R Navalesi.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Metabolic control affects plasma lipid and apolipoprotein levels in women, but not in men, with IDDM.

In order to evaluate if in insulin-dependent diabetes lipid and apolipoprotein levels are differently affected by metabolic control in men and women, we measured the concentrations of fasting plasma glucose, mean plasma glucose, glycosylated hemoglobin, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, and apolipoproteins A and B in 94 sex matched patients. Diabetic men and women were strictly comparable as far as age, relative body weight and metabolic control were concerned. In women, total and LDL cholesterol, triglycerides and apolipoprotein A correlated positively with HbA1 but not with fasting and mean plasma glucose. In men, no correlation between metabolic control and lipid and apolipoprotein levels was found. We conclude that, in diabetic women, the degree of metabolic control may affect the concentrations of plasma lipids, thus explaining, at least in part, the increased risk for coronary atherosclerosis in these patients.

Adult↗
PubMedDate not supplied

Individual teaching as a first-step intervention for the education of diabetic subjects.

The effects of individual teaching imparted during routine diabetologic counselling on the knowledge concerning diabetes and metabolic control, were assessed in 42 outpatients (28 IDDM; 14 NIDDM), attending the diabetic clinic (study group, SG). We evaluated the outcome of a multiple-choice questionnaire and fasting blood glucose (FBG), 24-h urine glucose (UG), mean regulation index (MRI) and glycated hemoglobin (HbA1), before and 60 days after providing information about diet (D), physical exercise (E) and hypoglycemic drugs (HD) or insulin therapy (IT). Results were compared with those obtained in a group of 57 age- and sex-matched patients (36 IDDM; 21 NIDDM) who did not receive individual teaching (control group, CG). Knowledge concerning diabetes at the second evaluation was significantly higher (p less than 0.001) in SG than in CG for D and IT, although an improvement was observed in all items. SG patients showed a significant improvement of knowledge (p less than 0.05) for D, a not significant improvement for HD and IT and no change for E. No change was observed for HbA1, MRI and UG, while a significant decrease (p less than 0.05) was observed for FBG in SG. At the second evaluation, FBG of SG patients was significantly lower (p less than 0.05) than that of CG patients. Our results go to show that individual teaching can improve the level of knowledge of patients without affecting metabolic control. Individual teaching during routine diabetologic counselling represents in our opinion an effective and economic educational model.

Adolescent↗
PubMedDate not supplied

Effects of guar-pasta on serum lipid levels in obese diabetic and non-diabetic women with normal lipids.

Alternative medications for hyperlipidemia management have been continuously searched for above all because currently employed drugs appear not to be effective or are poorly tolerated. Fibers, such as guar-gum, seem to be able to reduce cholesterol levels, but their extensive and long-term use is beset by the high incidence of gastrointestinal side-effects. In this study the administration of guar-enriched pasta has proved to reduce fasting and post-prandial cholesterol levels significantly in 15 obese normocholesterolemic women (5 diabetics and 10 non-diabetics). The women reported good palatableness of guar-pasta without any side-effects.

Adult↗
PubMedDate not supplied

Free insulin concentrations in immediately extracted plasma samples and their relationships to clinical and metabolic parameters in insulin-treated diabetic patients.

The relationships between free insulin and various clinical and metabolic parameters in insulin-treated diabetic patients are still not clear, possibly because of the technical difficulties in measuring free insulin. Recently, it has been demonstrated that in the presence of insulin antibodies only immediate centrifugation of blood and extraction of insulin antibodies provide an accurate evaluation of in vivo free insulin concentrations. In this study we evaluated the relationships between free and bound insulin levels, insulin antibodies, metabolic control and insulin requirement in 38 insulin-treated diabetic patients, in whom plasma free insulin was assayed in immediately processed samples. The main findings of our study are as follows. Free insulin concentrations ranged from 2.5 to 54 microU/ml; no difference was found between males and females; the unbound hormone level was inversely correlated to fasting plasma glucose (p less than 0.01) and HbA1c (p less than 0.02); a positive correlation was shown between free insulin and daily insulin dose; finally, free insulin concentrations were not correlated with insulin antibody binding.

Adult↗
PubMedDate not supplied

The metabolic effects of cyclosporin and tacrolimus.

The introduction of cyclosporin and, more recently, tacrolimus in the immunosuppression of transplanted patients has lead to prolonged graft survival and increased patients' life expectancy. It has been therefore possible to evaluate the effects of long-term treatment with these drugs and metabolic alterations in patients on cyclosporin or tacrolimus have been reported by several authors. In particular, the use of these drugs is associated with abnormalities of glucose and lipid metabolism. Post-transplant diabetes is more common with tacrolimus, probably due to more marked effects on the pancreatic beta-cells, whereas increased levels of cholesterol and triglycerides are more frequently associated with cyclosporin treatment, even though, in this latter case, steroid treatment seems to play a major role. Comparison and intervention studies must be planned to evaluate the best therapeutical approaches to control these abnormalities and to assess the possibility to further increase graft and patient survival by appropriate treatment of diabetes and hyperlipidemia.

Animals↗
PubMedDate not supplied

Measurable deficit of autonomic and sensory nerve function in asymptomatic diabetic patients.

In a group of 46 consecutive outpatients attending the diabetic clinic of our Metabolic Department, 30 insulin-dependent and 16 non-insulin-dependent diabetic patients in stable metabolic control, and in 38 age-matched controls, we measured vibration perception threshold with biothesiometer and autonomic function, by means of the five classical cardiovascular tests: R-R interval variations during deep breathing, Valsalva ratio, lying-to-standing, postural hypotension, and sustained handgrip. None of the patients complained of symptoms related to diabetic autonomic neuropathy (DAN) or sensory polyneuropathy. Vibration perception threshold positively correlated with Valsalva ratio (p < 0.05) and deep breathing (p < 0.01), and all of them correlated with age (p < 0.001), but not with duration of diabetes and metabolic control. Patients scored significantly lower than controls in vibration perception threshold and all of the autonomic function tests. According to the outcomes of cardiovascular tests ["Autonomic Score" (AS)] patients were divided into two different groups: presence (DAN+ = AS > or = 3) or absence (DAN- = AS < 3) of autonomic neuropathy. The DAN- group (n = 28, 60.9%) showed no significant differences from the DAN+ group (n = 18, 39.1%) in age, duration of diabetes, glycated hemoglobin, or body mass index. DAN+ patients had vibration perception threshold measured at the first toe tip and at external malleolus significantly higher than DAN- patients (p < 0.01 and p < 0.001, respectively) and controls (p < 0.005), as well as all the other cardiovascular tests except sustained handgrip. No difference in any of these items was observed between DAN- patients and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Hardness of plantar skin in diabetic neuropathic feet.

To evaluate if skin hardness in diabetic neuropathic feet was increased and if its eventual modifications could be correlated to the severity of neuropathy, we studied a group of diabetic outpatients with and without neuropathy. Patients, selected among those who were attending their routine screening for diabetic neuropathy at our diabetologic clinic, were divided into two groups according to the presence (ND+) or absence (ND-) of diabetic neuropathy with the criteria of the S. Antonio Consensus Conference on Diabetic Neuropathy. Patients then underwent an evaluation of vibration perception threshold (VPT) by means of a biotesiometer, measurement of skin hardness (DMT) by means of a durometer, and transcutaneous oxygen tension (TcPO2) determination. VPT was determined at allux (VPT-A) and external malleolus (VPT-M), DMT was measured at heel (DMT-H), at medial (DMT-M) and lateral (DMT-L) midfoot, and at posterior midcalf (DTM-C) as a control site; TcPO2 was evaluated at dorsum (TcPO2-D) and at medial midfoot (TcPO2-M), respectively. All measurements were performed on the nondominant side with the patients supine. Patients were compared with age and gender-matched healthy volunteers (Controls), who underwent the same evaluations in the same order. ND+ patients showed higher values of VPT than ND- and Controls, both at first toe and at malleolus analysis of variance (ANOVA) p<0.01), as well of DMT in all the three sites explored (ANOVA, p<0.01). Moreover, ND+ showed no difference in DMT among the sites, while both in ND- and in controls DMT-M was significantly (p<0.05) lower than DMT-H and DMT-L. No difference among the three groups were observed in TcPO2 measurements, and no difference in DMT-C was observed either. A significant correlation was observed between DMT-H and VPT-M (r2 = 0.516) and between DMT-M and VPT-A (r2 = 0.624) in ND+ patients. Skin hardness was diffusely increased in ND+ patients, and this increase strongly correlates with the severity of neuropathy. Simple, noninvasive determination of skin hardness could identify patient at potential risk to develop neuropathic foot ulcers.

Adult↗
PubMedDate not supplied

Endogenous digitalis-like factors (EDLF) in obese individuals: preliminary results.

We measured by RIA the serum and urinary digoxin-like immunoreactivity (EDLF) in 8 subjects with severe obesity and in 10 healthy, non-obese individuals (as a control group), to evidentiate whether circulating and urinary levels of EDLF are increased in obesity. For each individual, we measured the mean EDLF on two sera collected consecutively on two successive mornings, between 8-9 a.m. and the daily urinary EDLF excretion. Every subject collected his/her 24 hour urine in 5 different timed fractions. For each urine fraction, we measured the excretion of EDLF, electrolytes (Na and K), and creatinine. In obese people, the mean serum digoxin-like immunoreactivity (no. 8, 27.3 +/- 8.7 ng/L de) was significantly higher (unpaired t test, p = 0.0002) than in the controls (no. 10, 12.0 +/- 7.3 ng/L de), whereas control and obese subjects had superimposable 24 hour EDLF urinary excretion. Urinary excretion of EDLF significantly changed throughout the day in normals, but not in obese people. In a multiple stepwise regression analysis, urinary K+ and Na+ significantly (p less than 0.01) contributed to the regression with urinary EDLF (EDLF = 76.9 + 0.67 K+ - 0.24 Na+; R = 0.601, no. 40) in obese individuals. The in vivo kinetic and metabolic pathways of EDLF are conceivably different in obese and normal subjects. A difference in the production rate, binding to plasma proteins and/or removal mechanisms could explain the findings of higher circulating levels with normal EDLF urinary excretion in obese persons.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Do metformin and phenformin potentiate differently B-cell response to high glucose? An in vitro study on isolated rat pancreas.

The study investigated the effects of metformin and phenformin, at "therapeutic" concentrations, on the pancreatic A-, B- and D- cell response to glucose using the isolated perfused rat pancreas model. Changes in the rate of pancreatic lactate output after these biguanides were also evaluated. Metformin--at 1.5 micrograms/ml--and phenformin--at 100 ng/ml--were separately infused both at 160 mg/dl and 300 mg/dl glucose levels. Neither metformin nor phenformin affected glucagon or somatostatin secretion during these two metabolic stimuli with glucose, nor did they significantly influence insulin response to the lower glucose stimulus. Both metformin and phenformin enhanced insulin response to 300 mg/dl glucose infusion and increased the second phase of the B-cell secretory profile but only phenformin significantly enhanced the pancreatic lactate output rate during the 300 mg/dl glucose infusion. Infusion with dichloroacetate (a stimulator of the mitochondrial pyruvate oxidation) or with verapamil (a calcium antagonist) alone did not modify the insulin response to high glucose concentrations. During metformin infusion dichloroacetate neither modified metformin's effects on B-cell response to high glucose nor did it affect the pancreatic lactate output rate. On the other hand dichloroacetate opposed phenformin's effects on the B-cell response to high glucose and reversed the rise in the pancreatic lactate output rate. Verapamil inhibited the effect of metformin on the B-cell response to high glucose but failed to affect phenformin's influence on high-glucose induced insulin release. These data suggest both metformin and phenformin potentiate--at least in rats--the late phase of insulin secretory response to high glucose. However metformin seems to influence pancreatic B-cell activity mainly by facilitating the trans-membrane calcium ion influx responsible for the second phase of insulin release. Phenformin's influence seems indirect since it increases pancreatic lactate production which mediates the enhanced B-cell response to glucose.

Animals↗
PubMedDate not supplied

[Efficacy of sulfonylurea and sulfonylurea-benfluorex therapy in patients with type 2 diabetes treated with commercial sulfonylurea-biguanide combinations].

This study tests the possibility to avoid the use of phenformin in 40 type 2 (non insulin dependent) diabetic patients treated with the commercial sulphonylurea-phenformin combinations. In diabetic patients treated with sulphonylureas and phenformin at low dosage (glibenclamide 5 mg and phenformin 50 mg) it was possible to maintain good glycometabolic control using only the sulphonylurea gliclazide (160 mg/die). The diabetic patients on treatment with sulphonylureas and phenformin at higher dosage (glibenclamide 7.5 mg and phenformin 75 mg) may further improve their metabolic control when transferred to a gliclazide-benfluorex combination 160 mg and 300 mg/die, respectively. These results suggest the possibility of withdrawing or replacing phenformin in the therapy of type 2 diabetic patients without modifying their glycometabolic control.

Aged↗
PubMedDate not supplied

Salivary immunoreactive insulin concentrations are related to plasma free-insulin levels in insulin-treated diabetic patients.

Salivary immunoreactive insulin was measured in 45 insulin-treated diabetic patients directly from saliva samples by a radioimmunoassay procedure. Mean and median fasting salivary immunoreactive insulin was respectively 88.5 and 54.0 pmol/L (range 12.2-633.6 pmol/L); fasting salivary insulin values were positively correlated with steady-state plasma free-insulin levels measured in immediately extracted plasma samples (r = 0.62, p less than 0.001) and with daily insulin dose (r = 0.32, p less than 0.05). After subcutaneous injection of 15 U regular insulin in 6 type 1 diabetic patients, salivary insulin concentrations increase reflected that of plasma free-insulin during a 6 h period although with a 60 min time lag. Mean salivary insulin values and plasma free-insulin concentrations were significantly correlated to each other both at each time point (p less than 0.001) and when the mean salivary insulin levels were plotted against the mean plasma free-insulin values 60 min earlier (p less than 0.001). These results suggest that the measurement of salivary immunoreactive insulin (that is easier, faster and cheaper than plasma free-insulin assay) may be usefully employed as an approximation of plasma free-insulin concentrations for clinical and research purposes in patients with circulating anti-insulin antibodies.

Adult↗