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G Crepaldi

Publications and source records attributed to G Crepaldi.

At least 145 records · Page 8Linked to original sources
PubMed1990

Age and glucose tolerance in healthy subjects.

An important and still controversial issue is the role played by the aging process itself in the metabolic alterations observed in aged people. We previously reported that a group of normal elderly people exhibited glucose disposal comparable to that of young controls. In the present study we investigated the effect of age on beta-cell secretion, by analyzing C-peptide measurements. Ten elderly men (E, 70 +/- 2 years) with normal oral glucose test and ten young subjects (Y, 27 +/- 1 years) with matching ideal body weight formed the study group. They were studied under highly dynamic conditions by means of a 0.3 g/kg i.v. glucose tolerance test. Fasting glucose and insulin were not different in the two groups (Y: 87 +/- 2 mg/di, E: 88 +/- 3, p greater than 0.1; Y: 50 +/- 7 pM, E: 36 +/- 7, p greater than 0.05). Glucose-insulin data set was analyzed by means of the minimal model of glucose disappearance which provided two parameters for every individual, yielding a quantitative description of glucose utilization: i.e., SI, the index of insulin sensitivity, and SG, the fractional glucose disappearance at basal insulin (glucose effectiveness). Both parameters were unaltered by age (SI = Y: 6.30 +/- 0.41 10(-4)min-1/(microU/ml), E: 7.11 +/- 0.72, p greater than 0.1; SG = Y: 0.020 +/- 0.003 min-1, E: 0.019 +/- 0.002, p greater than 0.1). C-peptide time course in elderly people was systematically lower than in the control group (basal levels: Y: 252 +/- 36 pM, E: 129 +/- 17, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Immune dysfunction in the elderly: effect of thymic hormone administration on several in vivo and in vitro immune function parameters.

The effects of short-term thymic hormone administration on age-associated immune function were evaluated. Two groups of individuals greater than 65 years of age were treated for 30 days with thymic extracts (TP1) or placebo; before and after this treatment a panel of in vitro and in vivo parameters was determined according to a very rigorous experimental protocol. In most individuals, TP1 treatment was associated with an improvement in cutaneous delayed-type response to PPD. Moreover, an increase in a circulating T cell subpopulation bearing the CD45R surface antigen ("virgin" T cells), and in NK cell cytotoxic activity was also observed in some subjects. Finally, lymphocyte responsiveness to PHA tended to increase, while no effect on lymphocyte ability to produce IL-2 following mitogen stimulation was observed. These findings suggest that TP1 treatment may influence age-related alterations in immune function parameters in some subjects.

Aged↗
PubMed1990

Double-blind multicenter trial on a new medium molecular weight glycosaminoglycan. Current therapeutic effects and perspectives for clinical use.

The ability of glycosaminoglycans to bind to a wide number of biologically active macromolecules has already been investigated. Recent clinical trials on the possible therapeutic benefits of glycosaminoglycans must be placed in perspective, even if they appear to be particularly encouraging, especially as regards the glycosaminoglycan effects on certain coagulation factors. A multicenter, medium-term, double-blind, crossover trial was performed by several Italian Lipid Clinics to determine whether administration of a medium molecular weight glycosaminoglycan (Sulodexide) has a significant clinical effect. Patients affected by peripheral vascular disease and/or hyperlipidemia (type IIa, IIb and IV) were submitted to a 4-week wash-out period, followed by parenteral Sulodexide (S) or placebo (P) administration for 2 weeks, another 2 week wash-out period, parenteral crossover drug or P administration for 2 weeks and, finally, oral S administration for 6 months. Sulodexide lowered plasma viscosity and plasma fibrinogen in all patients. There was also a drop in triglycerides together with a rise in apo A-I and HDL-C in type IV hyperlipoproteinemics, whereas there was no significant effect on total or LDL-plasma cholesterol in type IIa and IIb patients. Moreover, there was a percent increase in peak flow and rest flow in the lower limbs of peripheral vascular disease patients. No side effects or intolerance phenomena were detected. The results indicate that Sulodexide administration may be useful in long-term treatment of patients with peripheral vascular disease and a concomitant increase in plasma triglycerides and/or fibrinogen and/or viscosity.

Adult↗
PubMed1990

Reduced beta-cell secretion and insulin hepatic extraction in healthy elderly subjects.

One factor responsible for the altered carbohydrate metabolism in elderly subjects is impaired insulin release; however, difficulties in directly measuring insulin secretion have limited studies on pancreatic activity and on the contribution of the liver to insulin delivery. This study investigated beta-cell performance and insulin hepatic extraction under dynamic conditions in normal elderly subjects. Two strictly comparable groups of 12 young controls (Y, 27 +/- 1 (SE) years, 73 +/- 3 kg) and 12 elderly men (E, 69 +/- 2 years, 73 +/- 3 kg) were chosen on the basis of normal OGTT and normal insulin sensitivity in order to investigate a "pure" age effect. The subjects underwent a 4-hour frequently sampled intravenous glucose tolerance test (FSIGT) (dose 0.3 g/kg). Although no significant differences were found between the fasting levels of glucose and insulin (respectively: E: 89 +/- 3 mg/dL versus Y: 87 +/- 2, P greater than .1; and E: 5.0 +/- 0.5 microU/mL versus Y: 6.8 +/- 1.0, P greater than .05), basal C-peptide was found to be lower in the old subjects: 0.43 +/- 0.06 ng/mL versus 0.70 +/- 0.11 (P less than .025). The patterns of glucose and insulin during the FSIGT were similar, whereas C-peptide concentration in E was systematically lower, suggesting a reduced insulin secretion. To verify this hypothesis, we analyzed FSIGT data with a mathematical model-based method that provides a noninvasive direct measurement of the time courses of insulin secretion and hepatic extraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Serum lipids, lipoprotein analysis and apoprotein A-I, A-II and B levels in Friedreich's ataxia.

Serum lipid, lipoprotein and apoprotein parameters were evaluated in 15 patients (7 males and 8 females) with Friedreich's ataxia. Serum lipid levels in patients showed no significant differences compared to controls. Small reduction in serum phospholipid and in total HDL and HDL3 cholesterol levels were observed, and the female patients presented a slight reduced total cholesterol level; among the serum apoproteins, apo B was reduced only in the males. The most interesting findings concerned the lipoproteins, since both lipid and protein masses of the VLDL, LDL and HDL2 fractions were reduced. In reference to lipoprotein composition, however, HDL2 was the most modified fraction, showing an important protein reduction. From this point of view, this lipoprotein seems the most responsible for the changes observed in our patients. The meaning of this modified lipoprotein pattern in the pathophysiology of Friedreich's ataxia is not clear.

Adolescent↗
PubMed1990

Absence of brown product FFI in nondiabetic and diabetic rat collagen.

Accumulation of brown products in long-lived proteins might be an important factor in determining long-term diabetic complications. Fluorescent chromophore 2-(2-furoyl)-4-(5)-(2-furanyl)-1H-imidazole (FFI), isolated from hydrolyzed brown products synthesized in vitro, was proposed as a specific brown product responsible for functional and structural changes in long-lived proteins. In this study, an attempt was made to demonstrate by means of collision spectroscopy the presence of FFI in collagen samples taken from diabetic rats. Diabetic rat collagen samples showed mean values of absorbance per milligram of 4-hydroxy-L-proline significantly higher than those observed in nondiabetic rats, suggesting higher FFI levels. Surprisingly, all collagen samples from diabetic and nondiabetic rats gave collision spectra in which no peak diagnostic of FFI presence was observed. These data suggest that the absorbance level observed in diabetic rats is not due to the presence of FFI but to structurally related compounds, which are being investigated by means of mass spectrometry.

Animals↗
PubMed1989

International trial of long-term dexfenfluramine in obesity.

In a randomised, placebo-controlled, double-blind study, 822 obese patients of both sexes were given either dexfenfluramine (dF), 15 mg twice daily (404), or placebo (418) in addition to a calorie-restricted diet for 1 year. Patients in both groups lost weight significantly in the first 6 months; after 6 months dF patients had a higher cumulative mean weight loss. Dropout rates were lower in dF patients than in placebo patients, mainly because of dissatisfaction with weight loss in the latter group. More than twice as many dF patients as placebo patients achieved a given weight loss; but more dF patients than placebo patients had transient side-effects (tiredness, diarrhoea, dry mouth, polyuria, and drowsiness).

Adult↗
PubMed1989

The life cycle of a low-molecular-weight protein of surfactant (SP-C) in 3-day-old rabbits.

To clarify the metabolic cycle of a low-molecular-weight protein of surfactant (SP-C), we obtained alveolar surfactant from 3 day old rabbits killed 24 h after the tracheal administration of 32P or L-[35S]methionine (donors). Aliquots of this naturally labelled surfactant were administered into trachea to 3-day-old rabbits (recipients) which were killed after 1 min or 3, 8 or 24 h. We then analyzed the radioactivity associated with SP-C and with saturated phosphatidylcholine in fractions of lung lavage fluid and in lung homogenate. We found that alveolar SP-C is turned over faster than saturated phosphatidylcholine, that alveolar macrophages do participate in the removal of SP-C and that SP-C does not enter the fraction of alveolar surfactant that remains unsedimented after ultracentrifugation. Considering the whole lung, SP-C and saturated phosphatidylcholine are turned over at a comparable speed.

Animals↗
PubMed1989

Na/H and Li/Na exchange in red blood cells of normotensive and hypertensive patients with insulin dependent diabetes mellitus (IDDM).

It has been shown that red blood cell Li/Na exchange, also called countertransport (Li/Na CTT) is increased in patients with insulin dependent diabetes mellitus (IDDM) with clinical or subclinical nephropathy and elevated blood pressure. Because recent experimental evidence confirms that red cell Li/Na CTT is a mode of functioning of the Na/H exchange (Na/H CTT), we have measured both transport modes in 23 IDDM (16 hypertensive and seven normotensive) and in eight normotensive controls with normal glucose tolerance. Na/H and Li/Na CTT were significantly increased in hypertensive compared to normotensive diabetics and controls. Na/H CTT was 78 +/- 28 mmol/L cell/h in hypertensive IDDM, 50 +/- 21 in normotensive IDDM, and 55 +/- 24 in the controls. Li/Na CTT was 0.37 +/- 0.13 mmol/L cell/h, 0.27 +/- 0.10, and 0.25 +/- 0.11, respectively. Na/H and Li/Na CTT were significantly correlated (r = .38, P less than .05). The proximal tubule sodium reabsorption, measured as the fractional Li+ reabsorption, was significantly correlated to red cell Na/H CTT (r = .38, n = 29, P less than .05), but not to the Li/Na CTT (r = .21, n = 29). In conclusion this work confirms that Na/H and Li/Na CTT are function modes of the same transporter and that an increased activity of Na/H CTT might play a role in the blood pressure increase in IDDM.

Adult↗
PubMed1989

Sodium metabolism in insulin dependent diabetic patients. Role of insulin and atrial natriuretic peptide.

Acute insulin administration shows an antinatriuretic effect in normal man. Thus it can be postulated that insulin therapy resulting in circulating hyperinsulinemia can lead to sodium retention and in turn to hypertension in insulin dependent diabetes. Moreover it has been proved that atrial natriuretic peptide (ANP) plays a major role in modulating natriuresis in man. The aim of the present study was to investigate the relationship between insulin and ANP in modulating sodium metabolism in seven insulin dependent diabetic patients in comparison with eight normal control subjects at baseline and during a saline infusion (2 mmol/kg/90 min) at euglycemic blood levels. Diabetics received a subcutaneous insulin infusion (0.015 U/kg/hr) resulting in a two fold higher plasma free insulin levels (16 +/- 2 microU/ml) than in control subjects (7 +/- 2 microU/ml). During saline challenge sodium excretion rate increased by 29 +/- 6% in control patients and only by 6 +/- 0.7% in diabetic patients (p less than 0.01). At baseline ANP plasma concentrations were significantly higher in diabetic patients than in control subjects (diabetics = 37 +/- 8 pg/ml and controls = 21 +/- 3 (p less than 0.01). After saline challenge ANP concentration rose to 71 +/- 9 pg/ml in control subjects, whereas no significant change above baseline values was shown by diabetic patients.

Atrial Natriuretic Factor↗
PubMed1988

Efficacy of captopril in hypertensive diabetic patients.

Twenty hypertensive diabetic patients (10 with type I and 10 with type II) were treated with captopril, 50 mg twice a day, for three months. The drug was effective as monotherapy in 16 patients. An additional nine months of follow-up was obtained in 12 of these patients (four with type I and eight with type II) who did not need the addition of diuretics to achieve normal blood pressure. For these patients with long-term treatment, since there was no substantial difference between those with type I and those with type II, the data were pooled. Mean arterial pressure significantly decreased shortly after treatment was begun and the reduction was maintained. No significant change was induced by captopril in urine volume, osmolar clearance, and serum and urinary values of sodium, chloride, calcium, and magnesium, whereas significant reduction was found in fractional excretion of potassium and phosphate. The baseline levels of proteinuria were only slightly elevated, yet they fell in all patients during treatment. All patients maintained satisfactory control of carbohydrate metabolism, and none of them required substantial changes in hypoglycemic treatment. The administration of captopril as monotherapy appears to be an effective and safe way of lowering blood pressure in diabetic hypertensive patients, even in the long term, without effects on renal function and in carbohydrate metabolism.

Adult↗
PubMed1988

Collisional spectroscopy as a screening procedure for the determination of 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole from acid hydrolysis of B-poly(L-lysine) and B-albumin.

The direct determination of 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole (FFI), present in the acid hydrolysis products of B-poly(L-lysine) and B-albumin and which appears to be a key intermediate in the physicochemical changes occurring during the incubation of protein with glucose, has been carried out by collisional spectroscopy, using a commercial double-focusing, reverse-geometry mass spectrometer and without any sample derivatization and chromatographic separation procedures.

Albumins↗
PubMed1988

A single-blind study of doxazosin in the treatment of mild-to-moderate essential hypertensive patients with concomitant noninsulin-dependent diabetes mellitus.

Doxazosin, a selective alpha 1-inhibitor, was assessed for antihypertensive efficacy, effect on lipid parameters, and safety profile in 21 hypertensive patients with noninsulin-dependent diabetes mellitus. The study involved a 2- to 4-week baseline period, a 10-week period in which patients received doxazosin, 1 to 8 mg, once daily, and a 4-week maintenance period. All 16 of the efficacy evaluable patients (100%) had their blood pressure controlled (sitting diastolic blood pressure less than or equal to 90 mm Hg) at a mean dose of 3.6 mg once daily. For efficacy evaluable patients mean sitting blood pressure was significantly (p less than 0.05) reduced by 26/17 mm Hg at the final visit. Five patients each reported a single side effect and none was severe. No patients required dose reduction or discontinuation of therapy because of side effects. No clinically significant laboratory changes were apparent, and no trends were observed with regard to organ systems or correlations with dose or duration of treatment. The investigators' global assessment of efficacy of once-daily doxazosin therapy was excellent or good for 15 patients and fair for six patients. The overall assessment of patient toleration was excellent or good for 19 patients, fair for one, and not reported for one. High-density lipoprotein cholesterol was significantly increased (p = 0.03). From baseline to final visit, there was a highly significant reduction of 30% (p less than 0.005) in calculated coronary heart disease risk score on the basis of the Framingham equation.

Adrenergic alpha-Antagonists↗
PubMed1988

Plasma lipid lowering activity of acipimox in patients with type II and type IV hyperlipoproteinemia. Results of a multicenter trial.

A multicenter study was carried out in 130 out-patients to assess the plasma lipid lowering activity of acipimox in type IIa, IIb and IV hyperlipoproteinemia. The study consisted of two periods, an 8-week randomized, double-blind comparison of active drug versus placebo and a 16-week open follow-up with acipimox (400 mg and 250 mg t.i.d., respectively, in type II and IV patients). During the double-blind phase acipimox, compared to placebo, showed a highly significant triglyceride lowering effect in type IV patients (-43% vs. +4%, P less than 0.01), while reducing plasma cholesterol significantly in type II patients (-7% vs. -3%, P less than 0.05). Further reductions in plasma lipids were obtained in both types of hyperlipoproteinemia after the 16-week follow-up. In type II patients, total cholesterol fell by 9% in the former acipimox group and 17% in the former placebo group, whereas a 34% reduction in triglycerides was found in type IV patients previously treated with placebo. Treatment had to be discontinued in 4 patients during the double-blind phase and in 5 patients during follow-up, because of adverse events such as skin reactions and gastric disturbances. Statistical analysis of hematological and biochemical variables expressing safety did not show any significant change during treatment.

Adult↗
PubMed1988

Insulin sensitivity and beta-cell responsivity are not decreased in elderly subjects with normal OGTT.

Glucose intolerance has been observed often in elderly subjects, but it is not yet clear whether this impaired metabolic state is due to the aging process itself or is secondary to the appearance of other age-related variables. This study attempts to elucidate the effect of age in itself on factors controlling glucose tolerance. Several metabolic parameters were measured in 10 young male controls (23-29 yr) and 17 nonhospitalized, healthy, nonobese, old (60-80 yr) male subjects. Insulin binding to circulating cells was performed along with the intravenous glucose tolerance test, and the data were analyzed by the minimal model method. This approach yields the following measures: tissue insulin sensitivity (SI), fractional glucose disappearance at basal insulin (glucose effectiveness, SG), and first (phi 1) and second (phi 2) phase beta-cell responsiveness to glucose. Insulin-binding capacity to monocytes and erythrocytes was respectively 6.03% +/- 0.57% and 5.96% +/- 0.53% (elderly), 5.97% +/- 0.39% and 5.36% +/- 0.57% (young); SI was 6.20 +/- 0.59 X 10(4) min-1/(microU/mL) (elderly) and 6.35 +/- 0.30 (young); SG was 0.016 +/- 0.002 min-1 (elderly) and 0.019 +/- 0.003 (young); phi 1 was 1.84 +/- 0.29 min-1 (microU/mL)/(mg/dL) (elderly) and 3.37 +/- 0.84 (young); phi 2 was 13.80 +/- 1.78 X 10(4) min-2 (microU/mL)/(mg/dL) (elderly) and 9.59 +/- 2.65 (young). These results show no change with aging of tissue insulin sensitivity and an intact beta-cell activity, suggesting that age per se does not contribute to the deterioration of glucose tolerance when the effect of other age-related variables, eg, obesity and physical inactivity, is precluded.

Adult↗
PubMed1988

Effects of imidazole-2-hydroxibenzoate on glycosaminoglycan and albumin urinary excretion in type 1 diabetic patients.

The effect of imidazole-2-hydroxibenzoate on urinary excretion rates of glycosaminoglycans and albumin in 22 insulin-dependent diabetics with albumin excretion rates under 300 mg/day was evaluated in a 165-day double blind crossover study. Unlike placebo, the drug reduced glycosaminoglycan and albumin excretion rates significantly after 40 and 60 days of treatment, and the effects were significantly intercorrelated. Moreover, a parallel reduction in urinary excretion of N-acetyl-beta-D-glucosaminidase was also observed. These pharmacological effects may have a positive impact on the subsequent natural history of diabetic nephropathy.

Acetylglucosaminidase↗
PubMed1988

Study of some early immunological parameters in aging humans.

We studied the correlation between the in vitro lymphocyte proliferative response and some early parameters of lymphocyte activation in aged people. While a consistent number of elderly subjects showed significantly decreased proliferative responses to mitogen stimulation, interleukin-1 (IL-1) production and IL-2 receptor/DR antigen expression were comparable to those of young controls. The reduction in IL-2 production observed in some aged donors did not correlate with the decreased proliferative activity in response to mitogen. Moreover, addition to the cultures of recombinant IL-2 was not capable of restoring the proliferative response to normal levels. These data on the whole seem to argue against a primary involvement in age-associated lymphocyte hyporesponsiveness of an alteration in the early phases of lymphocyte activation engaging the complex lymphokine/receptor network.

Adult↗