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Biomedical subjects

A D'Amore

Publications and source records attributed to A D'Amore.

At least 19 recordsLinked to original sources
PubMed2006

Effects of olanzapine on aggressiveness in heroin dependent patients.

This study compared the anti-aggressiveness effects of the atypical anti-psychotic olanzapine with that of selective serotonin reuptake inhibitors (SSRI) and benzodiazepines (BZD) among patients with heroin dependence submitted to opioid-agonists substitution treatment. Sixty-seven (67) patients who met the DSM-IV criteria for heroin dependence and showed aggressive personality traits, not affected by comorbid schizophrenia or bipolar disorder, accepted to participate in a 12-week prospective, observational trial. Patients were included into two subgroups in relationship with treatment, for the evaluation of the endpoints at week 12: group 1: substitution treatment in combination with OLA (32 patients); group 2: substitution treatment in combination with fluoxetine/paroxetine and clonazepam (35 patients). Efficacy measures were Buss Durkee Hostility Inventory (BDHI), Symptoms Check List-90 (SCL 90) anger--hostility scores, incidence rates of aggressive incidents and attacks. The rates of patients who remained in treatment at week 12 in group 1, treated with OLA, and group 2, treated with SSRI and BDZ, were not significantly different (17 = 53.1% vs 16 = 45.7%). BDHI total, direct aggressiveness, verbal aggressiveness scores, SCL 90 aggressiveness scores and aggressive incidents rates showed a significantly more consistent decrease from baseline in group 1 than in group 2 subjects, in the patients who completed the treatment (p < 0.001; p < 0.01; p < 0.05; p < 0.01; p < 0.001). Among the completers, 69.3% achieved early full substance abuse remission, while 30.7% achieved partial substance abuse remission, with no significant difference between 1 and 2 treatment subgroups. Although obtained by an observational--open clinical study, with multiple limitations, our findings suggest that OLA may be useful as an adjunctive agent in reducing aggressive/hostile behaviour in heroin addicted individuals during maintenance substitution treatment. Otherwise, atypical anti-psychotic OLA seems to be unable to improve the outcome in terms of addictive behavior and relapse risk in the addicted patients not affected by overt psychotic disorders.

Adult↗
PubMed2006

Data collection from very low birthweight infants in a geographical region: methods, costs, and trends in mortality, admission rates, and resource utilisation over a five-year period.

AIMS: 1. To determine the survival and morbidity of infants at discharge with a birthweight of less than 1500 g in the geographically defined population of East Anglia. 2. To demonstrate a cost-effective method of regional data collection. 3. To determine whether there were any changes in the demand for neonatal care. STUDY DESIGN AND SUBJECTS: A prospective cohort analysis using a single database to collect data on 1244 very low birthweight infants from eight neonatal units in one Region from 1993 to 1997. RESULTS: Estimated ascertainment of VLBW infants to the study was 96%. Over the 5 years survival rates were stable (75-79%). 52% of deaths in infants admitted for neonatal care occurred on day 1, with just 15% of deaths occurring after 28 days of life. Mortality risk significantly decreased with increasing gestational age at birth. Compared to 22-25-week old infants, the mortality risk decreased by 65% for 26-27-week old infants (OR 0.35 95% CI (0.21, 0.59)) and by 92% for 32-39-week old infants (OR 0.08 95% CI (0.03, 0.21)) with intermediate odds ratios of 0.22 (0.12, 0.42) and 0.13 (0.06, 0.28) for the 28-29 and 30-39 weeks gestation, respectively. Higher birthweight, after adjusting for gestation also decreased the mortality risk (OR 0.78 per 100 g difference, 95% CI (0.71, 0.86)). No change was seen in the number of extremely preterm infants admitted for intensive care or resource utilisation, although a significant increase was seen in the number of infants dying in delivery rooms. There was a reduction in the reported incidence of pulmonary interstitial emphysema (10-4%) but no change in the number of ventilation days or the rate of chronic lung disease. The mean maternal age increased from 27.7 years to 28.9 years during the study. Maternal steroid administration increased (30% to 59%) and was associated with a decreased risk of mortality (OR 0.44, 95% CI: 0.31-0.62). CONCLUSIONS: It is possible to collect useful data from the neonatal period at a reasonable cost from a geographically defined population. This information was used for informing clinicians, counselling parents and in the era of managed clinical networks will be useful in guiding the provision of effective health care resources.

Cohort Studies↗
PubMed2005

Outcome at 2 years for very low birthweight infants in a geographical population: risk factors, cost, and impact of congenital anomalies.

AIM: To determine the type and rate of disability at 2 years of age in infants born in the geographically defined population of East Anglia with a birthweight less than 1500 g and to assess the risk factors for disability. STUDY DESIGN: A prospective cohort analysis from all eight neonatal units in East Anglia from 1993-1997 using a single database. METHODS: Local paediatricians assessed children at 2 years using the Health Status Questionnaire and data collection was centrally coordinated. RESULTS: Outcomes for 947 children, 99% of survivors, were available, 74 (7.8%) had severe disability and this was significantly associated with gestational age (p<0.0005), birthweight (p<0.0005) and sex (p=0.046). Major congenital abnormality contributed 27% of all severe disability. The overall cerebral palsy rate was 6.2%, nine children were blind and five had sensorineural hearing loss requiring aids. These children had a high level of use of community services with 19% of the cohort being referred to one or more community service. ELBW infants or those born <30 weeks gestation were 1.5 times and twice as likely to have moderate or severe disability and 2.3 and 5.4 times as likely to have cerebral palsy as those weighing 1000 to 1500 g or >30 weeks gestation. Boys were at higher risk of adverse outcome. CONCLUSIONS: The study was able to define the increased risk associated with being born at lower gestational age or lower birthweight and demonstrates successful ascertainment of outcomes for large local populations at a reasonable cost.

Caregivers↗
PubMed1998

Non-accidental injury inflicted on a child with an air weapon.

A case of non-accidental injury to an infant caused by the discharge of an air pistol is presented, the first such case to be reported. A two-month-old baby was shot at close range by his father with a .177 air pistol. A false account of the cause of the injury was given by the father and initially supported by the mother. The pellet penetrated the skin in the centre of the child's forehead and lodged in the anterior wall of the sagittal sinus. It was removed under general anaesthetic and the child made an uncomplicated recovery. The father was subsequently convicted and jailed for the assault. The relevant literature on air weapon injuries and bizarre forms of child abuse is discussed.

Adult↗
PubMed1996

Glucose tolerance and insulin action in healthy centenarians.

Advancing age has been found to be associated with a decline in insulin action. Nevertheless, no study has been conducted in healthy centenarians. Our study investigates glucose tolerance and insulin action in centenarians. Fifty-two subjects were enrolled. The subjects were divided in three groups as follows: 1) adults (< 50 yr; n = 20);2) aged subjects (> 75 yr; n = 22); and 3) centenarians (> 100 yr; n = 14). Body composition was studied by bioimpedance analysis. In all subjects, an oral glucose tolerance test and euglycemic glucose clamp were performed. Centenarians have a lower fat-free mass (FFM) than aged subjects and adults, whereas fasting plasma glucose, triglycerides, free fatty acids, urea, and creatinine were not different in the groups studies. Centenarians had a 2-h plasma glucose concentration (6.0 +/- 0.2 mmol/l) that was lower than that in aged subjects (6.6 +/- 0.5 mmol/l, P < 0.05) but not different from adults [6.4 +/- 0.4 mmol/l, P = not significant (NS)]. During the clamp, plasma glucose and insulin concentrations were similar in the three groups. In these conditions, centenarians had a whole body glucose disposal (34.1 +/- 0.6 mumol.kg FFM-1.min 1) that was greater than that in aged subjects (23.3 +/- 0.5 mumol.kg FFM-1.min-1 P < 0.01) but not different from adults (34.6 +/- 0.5 mumol/kg x min, P = NS). In conclusion, our study demonstrates that centenarians compared with aged subjects had a preserved glucose tolerance and insulin action.

Adult↗
PubMed1995

Low-dose Iloprost infusion improves insulin action and non-oxidative glucose metabolism in hypertensive patients.

Fourteen hypertensive (174.3/98.3 mmHg) non-diabetic patients were given a euglyceamic glucose clamp along with infusion of 0.9% NaCl and the prostacyclin (PGI2) analogue Iloprost (0.7 ng x kg x min(-1)). Substrate oxidation was also determined by indirect calorimetry. Over the last 60 min of the clamp, Iloprost vs saline improved whole body glucose disposal (WBGD) (35 vs 28.3 micromol x kg(-1) LBM) and non-oxidative glucose metabolism (24.7 vs 18.1 micromol x kg(-1) LBM x min(-1). Iloprost delivery was associated with a significant decrease in membrane microviscosity (0.253 vs 0.205), but did not affect arterial blood pressure and heart rate. In nine patients, skeletal muscle blood flow (SMBF) and insulin-stimulated glucose uptake (GU) were also studied. At the end of the study, despite a similar SMBF (37 vs 38 ml x min(-1) x kg(-1)), GU (0.55 vs 0.46 mmol x l(-1)) was significantly increased by Iloprost infusion. Percentage decrease in membrane microviscosity was correlated with percentage increase in WBGD (r = 0.65) and non-oxidative glucose metabolism (r = 0.68). In conclusion, low-dose Iloprost infusion improves insulin action and non-oxidative glucose metabolism in hypertensive patients.

Blood Glucose↗
PubMed1995

Opposite effects of short- and long-term fatty acid infusion on insulin secretion in healthy subjects.

Our study investigates short- and long-term effects of infusion of non-esterified fatty acids (NEFA) on insulin secretion in healthy subjects. Twelve healthy individuals underwent a 24-h Intralipid (10% triglyceride emulsion) infusion at a rate of 0.4 ml/min with a simultaneous infusion of heparin (a bolus of 200 U followed by 0.2 U/min per kg body weight). After an overnight fast (baseline), at 6 and at 24 h of Intralipid infusion and 24 h after Intralipid discontinuation (recovery test), all subjects underwent an intravenous glucose tolerance test (iv-GTT) (25 g of glucose/min). Intralipid infusion caused a threefold rise in plasma NEFA concentrations with no difference between the 6- and the 24-h concentrations. Compared to baseline acute insulin response (AIR) (AIR = 63 +/- 8 mU/l), short-term (6-h) Intralipid infusion was associated with a significant increase in AIR (86 +/- 12 mU/l p < 0.01); in contrast, long-term (24-h) Intralipid delivery was associated with inhibition of AIR (31 +/- 5 mU/l) compared to baseline (p < 0.001) and to the 6-h (p < 0.03) triglyceride emulsion infusion. Intralipid infusion was associated with a progressive and significant decline in respiratory quotient (RQ). A positive correlation between changes in fasting plasma NEFA concentrations and AIR at the 6-h infusion (r = 0.89 p < 0.001) was found. In contrast, at the end of the Intralipid infusion period, changes in plasma NEFA concentrations and AIR were negatively correlated (r = -0.87 p < 0.001). The recovery test showed that fasting plasma NEFA concentrations, RQ and AIR had returned to baseline values. In the control study (n = 8) 0.9% NaCl infusion did not mimick the effect of Intralipid. In conclusion, our study demonstrates that short- and long-term exposures of beta cells to high plasma NEFA concentrations have opposite effects on glucose-induced insulin secretion.

Adult↗
PubMed1995

Body composition, body fat distribution, and resting metabolic rate in healthy centenarians.

Our study investigated body composition and body fat distribution in healthy centenarians. Body composition, body fat distribution, and resting metabolic rate (RMR) were studied in 40 adult subjects aged < 50 y, 35 aged subjects > 75 y, and 15 healthy centenarians aged > 100 y. Body composition was determined by bioimpedance analysis, body fat distribution was calculated as waist-hip ratio (WHR), and RMR was calculated by using the Arciero-Poehlman formula. Healthy centenarians had a cognitive impairment and degree of disability greater than aged subjects. Despite such differences, fat-free mass (FFM) and RMR were not different in centenarians compared with aged subjects but were lower than in adult subjects. In contrast, healthy centenarians had a WHR lower than that of aged subjects but not different from that of the adult subjects. After the level of physical activity and degree of disability were adjusted for, FFM (44 +/- 2.7 and 40 +/- 1.1 kg; P < 0.05) and RMR (6757 +/- 761 and 5891 +/- 723 kJ/24 h; P < 0.05) were significantly higher in healthy centenarians than in aged subjects, respectively. Independent of age, sex, body weight, degree of disability, level of physical activity, and fasting plasma triiodothyronine, there was a strong correlation between RMR and FFM (r = 0.50, P < 0.05) in healthy centenarians. In conclusion, healthy centenarians had a lower FFM and higher body fat content than aged subjects. Level of physical activity and degree of disability seem to be the major determinants for explaining such differences.

Adipose Tissue↗
PubMed1995

Left ventricular hypertrophy is associated with a stronger impairment of non-oxidative glucose metabolism in hypertensive patients.

Hypertensive patients with left ventricular hypertrophy (LVH) have a higher degree of hyperinsulinaemia than hypertensive patients without LVH. Obese patients with LVH have also been demonstrated to have a very low glucose disappearance rate after an intravenous glucose bolus. No studies have investigated the difference in insulin action and substrate oxidation in hypertensive patients with and without LVH. For this reason 36 subjects were enrolled for our study: (1) healthy control subjects (n = 10); (2) hypertensive patients without LVH (n = 12); and (3) hypertensive patients with LVH (n = 14). All subjects underwent an oral glucose tolerance test (OGTT, 75 g of glucose) and a euglycaemic hyperinsulinaemic glucose clamp (insulin infusion rate, 7.1 pmol (kg min)-1 for 120 min). In this latter test indirect calorimetry allowed substrate oxidation determination. Echocardiographic methods allowed LVH assessment. Hypertensive patients with LVH had the lowest insulin-mediated nonoxidative glucose metabolism compared to hypertensive patients without LVH (P < 0.01) and to healthy subjects (P < 0.001). In the whole group of hypertensive patients (n = 26), partial correlations showed left ventricular mass index (LVMI) associated with fasting plasma insulin levels (r = 0.44 P < 0.005), insulin-mediated whole body glucose disposal (r = -0.41 P < 0.01) and nonoxidative glucose metabolism (r = -0.33 P < 0.04) independently of age, body weight, systolic blood pressure and plasma catecholamines levels. In conclusion, our data provide evidence that LVH in hypertensive patients is associated with a worsening in nonoxidative glucose metabolism.

Blood Glucose↗
PubMed1995

Low-dose iloprost infusion improves insulin action in aged healthy subjects and NIDDM patients.

OBJECTIVE: To investigate the effect of iloprost infusion on insulin action. RESEARCH DESIGN AND METHODS: Thirteen healthy subjects and 13 non-insulin-dependent diabetes mellitus (NIDDM) patients matched for age (68.2 +/- 0.5 vs. 67.9 +/- 0.5 years, NS), gender ratio (7 men:6 women vs. 6 men:7 women), body weight, body fat distribution, arterial blood pressure, and plasma triglyceride levels (1.89 +/- 0.09 vs. 1.87 +/- 0.08 mmol/l, NS) were studied. In eight healthy subjects and eight NIDDM patients, we studied insulin action by euglycemic glucose clamp (insulin infusion rate 2 mU.kg-1.min-1) along with saline and iloprost delivery (0.7 ng.kg-1.min-1). In the other five subjects of each group, forearm blood flow and insulin-mediated glucose uptake during saline and iloprost infusion (0.7 ng.kg-1.min-1) were investigated. RESULTS: Iloprost infusion improved insulin-stimulated whole-body glucose uptake and oxidative and nonoxidative glucose metabolism in both study groups. Forearm blood flow under basal conditions and with insulin infusion (2 mU.kg-1.min-1) did not show any significant difference from that during saline and iloprost infusion (0.7 ng.kg-1.min-1) in healthy subjects and diabetic patients. CONCLUSIONS: Iloprost infusion improves insulin action in healthy subjects and NIDDM patients.

Aged↗
PubMed1994

Evidence for a relationship between oxidative stress and insulin action in non-insulin-dependent (type II) diabetic patients.

Ten healthy subjects and 30 non-insulin-dependent (type II) diabetic patients matched for age, gender ratio, body mass index, lean body mass (LBM), waist to hip ratio, and arterial blood pressure volunteered for the study. In all subjects, fasting plasma free radical (O2-) levels and basal membrane lipid fluidity (MLF) and protein mobility (MPM) were determined. The whole group of subjects underwent a euglycemic hyperinsulinemic glucose clamp with simultaneous indirect calorimetry for substrate oxidation determination. Diabetic patients versus controls displayed higher fasting plasma glucose (8.3 +/- 0.4 v 5.1 +/- 0.4 mmol/L, P +/- .001), O2- (0.48 +/- 0.02 v 0.16 +/- 0.02 mumol/L x min), and hemoglobin A1c ([HbA1C] 7.9% +/- 0.4% v 5.7% +/- 0.3%, P < .03) levels and a stronger reduction in basal MLF (0.243 +/- 0.006 v 0.318 +/- 0.009, P < .003) and basal MPM (0.348 +/- 0.003 v 0.518 +/- 0.010, P < .002). Whole-body glucose disposal (WBGD) and oxidative and nonoxidative glucose metabolism were also significantly lower in diabetics than in controls. In diabetic patients (n = 30), plasma O2- levels correlated with basal MLF (r = -.59, P < .005), basal MPM (r = -.84, P < .001), fasting plasma insulin level (r = .51, P < .004), WBGD (r = -.53, P < .002), and nonoxidative (r = -.45, P < .01) glucose metabolism. In conclusion, our results demonstrate that a relationship between plasma O2- levels and insulin action occurs in non-insulin-dependent diabetics.

Aged↗
PubMed1994

Total-body and myocardial substrate oxidation in congestive heart failure.

Congestive heart failure is a condition associated with increased plasma norepinephrine levels, which have been demonstrated to impair glucose handling. In the present study, 10 patients suffering from congestive heart failure and 10 healthy age- and body mass index-matched subjects were submitted to a hyperinsulinemic (insulin infusion rate, 0.5 mU/kg.min-1) glucose clamp, while simultaneous D-3H-glucose infusion and indirect calorimetry allowed for determination of glucose turnover parameters and substrate oxidation, respectively. On a separate day, basal local (myocardial) indirect calorimetry was also performed. Our data demonstrate that in congestive heart failure, fasting myocardial glucose oxidation (Gox) was inhibited with a simultaneous increase in lipid oxidation (Lox). In our patients, a significant decrease in total-body insulin-stimulated glucose metabolism (31.0 +/- 0.5 v 20.3 +/- 0.4 mumol/kg.min-1, P < .01) and nonoxidative glucose metabolism (18.9 +/- 1.1 v 11.0 +/- 0.5 mumol/kg.min-1, P < .05) was also found. Such latter changes were also associated with a simultaneous overdrive of Lox (0.4 +/- 0.2 v 1.9 +/- 0.2 mumol/kg.min-1, P < .02) that was correlated with an enhanced availability of plasma free fatty acids (FFAs).

Aged↗
PubMed1994

Plasma vitamin C affects glucose homeostasis in healthy subjects and in non-insulin-dependent diabetics.

In aged healthy (n = 10) and non-insulin-dependent (type II) diabetic (n = 10) subjects matched for age [67.3 +/- 0.5 vs. 68.0 +/- 0.4 yr, P = not significant (NS)], body mass index (25.7 +/- 0.7 vs. 26.0 +/- 0.2 kg/m2, P = NS), gender ratio [6 males (M)/4 females (F) vs. 5 M/5 F], and mean arterial blood pressure (104 +/- 6 vs. 105 +/- 9 mmHg, P = NS), we determined the changes in insulin secretion and action after vitamin C infusion and the relative increase in plasma vitamin C levels. At the highest vitamin C infusion rate (0.9 mmol/min) the increase in plasma vitamin C levels did not affect B cell response to glucose, but it improved Conard's K values and whole body glucose disposal in healthy subjects and in diabetic patients. In both groups of subjects vitamin C-mediated increase in insulin action was mainly due to an improvement in nonoxidative glucose metabolism. After fasting, plasma vitamin C levels correlated with basal whole body glucose disposal (r = -0.44, P < 0.05; n = 20). After vitamin C infusion, percent change in plasma vitamin C level correlated with the percent decline in membrane microviscosity (r = 0.53, P < 0.01; n = 20) and increase in whole body glucose disposal (r = 0.63, P < 0.003; n = 20). In conclusion, plasma vitamin C levels seem to play a role in the modulation of insulin action in aged healthy and diabetic subjects.

Aged↗
PubMed1994

[Echographic markers of chromosome abnormalities].

Many recent studies have identified biometric parameters which can be used as screening factors in the diagnosis of chromosomic anomalies. This derives from the assertion that karyotype testing in over-35-year-old women alone only allows 20-30% of fetuses suffering from chromosomic anomalies to be diagnosed. The majority of these fetuses remain undiagnosed during the prenatal period given that a high percentage of younger women are excluded from screening. For a long time researchers have hoped to introduce the assay of clinical and instrumental parameters thus allowing anomalous fetuses to be diagnosed in under-35-year-old women. It is now possible to define a biochemical parameter in maternal sera which can identify women at risk and refer them for cytogenetic tests: AFP assay and still more recently the contemporary assay of AFP, estriol and beta-HCG allows greater diagnostic accuracy. However, even using this method only part of those fetuses with chromosomic alterations are identified. Since it is unlikely that screening could be performed without indications in the under 35-year-old age group, it is important to identify routine echographic parameters which can then serve as the indication for subsequent cytogenetic tests and a definitive diagnosis. In this way, by integrating ultrasonographic examination, using biometric and morphological tests, with a biochemical evaluation it will be possible to achieve a higher percentage of diagnosis. This paper examines the most common malformations including trisomy 13, trisomy 18 and trisomy 21 syndromes, Turner's syndrome and triploidy, together with the main echographic findings which accompany them.

Adult↗
PubMed1993

Different contribution of substrates oxidation to insulin resistance in malnourished elderly patients with cancer.

BACKGROUND: The relative contribution of malnutrition and cancer to insulin resistance in elderly patients is still poorly understood. METHODS: Twenty malnourished and 15 well-nourished patients with cancer matched for age (70 +/- 0.3 versus 69 +/- 0.3 years; P = not significant), mean arterial blood pressure (104 +/- 8 versus 107 +/- 7 mm Hg; P = not significant), gender ratio (10 males/10 females versus 7 males/8 females), and sedentary life style underwent an euglycemic glucose clamp. Simultaneous infusion of 3-D-H-glucose and indirect calorimetry allowed the authors to determine glucose turnover parameters and analyze substrates oxidation. RESULTS: Malnourished patients displayed a reduced total body glucose metabolism (36 +/- 2 versus 31 +/- 3 mumol/kg of lean body mass x min P < 0.04) despite higher glucose oxidation. In the same group of patients, the authors demonstrated a significant increase in lipid oxidation and the lack of the inverse relationship between glucose and lipid oxidation (r = 0.07; P = not significant). Insulin infusion enhanced glucose oxidation and suppressed lipid oxidation, but such changes were at lower extent in malnourished patients. CONCLUSIONS: Our study confirms the presence of insulin resistance in malnourished patients and demonstrates the relative contribution of substrates oxidation to the insulin resistance itself.

Aged↗
PubMed1993

Effects of physiological plasma insulin levels on glucose turnover parameters in familial hypercholesterolemia.

Eight young, non-obese patients with primary familial hypercholesterolemia (FH) and 8 healthy subjects matched for age, body mass index, lean body mass, plasma triglyceride and HDL-levels and arterial blood pressure were selected from a lipid clinic. Patients with FH had higher plasma LDL-cholesterol (8.3 +/- 0.5 vs. 4.1 +/- 0.2 mmol/l, P < 0.001) than controls but similar plasma triglyceride (1.15 +/- 0.04 vs. 1.10 +/- 0.02 mmol/l P = NS) levels. Both study groups were submitted to a euglycaemic hyperinsulinemic glucose clamp combined with simultaneous infusion of [3H]glucose to measure insulin action on whole-body glucose uptake and on hepatic glucose production. Two insulin infusion rates (0.15 mU/kg per min from 0 to 120 min and 0.30 mU/kg per min from 121 to 240 min) were used resulting in similar plasma insulin levels in both groups studied. Our results demonstrate that both whole-body glucose uptake and hepatic glucose output are similar in the fasting state as well as during insulin administration in both groups of subjects. We conclude that, in the absence of other causes of insulin resistance, isolated hypercholesterolemia is associated with normal sensitivity to insulin in both liver and peripheral tissues.

Adult↗
PubMed1993

Evidence for a relationship between free radicals and insulin action in the elderly.

In forty healthy subjects with normal glucose tolerance divided by age into four groups (group A, subjects with mean age < 25 years [n = 10]; group B, subjects with mean age < 40 years [n = 9]; group C, subjects with mean age < 60 years [n = 11]; group D, subjects with mean age > 75 years [n = 10]) and were matched for body mass index (BMI), lean body mass (LBM), mean arterial blood pressure, and sedentary life style, we determined the plasma O2- production, reduced to oxidized glutathione level ratio (GSH/GSSG), and plasma membrane microviscosity. Euglycemic hyperinsulinemic (1 mU/kg.min-1 for 120 minutes) glucose clamp with simultaneous D-3-H glucose infusion and indirect calorimetry allowed determination of glucose turnover parameters and substrate oxidation. In the oldest group of subjects, a significant increase in plasma O2-production and membrane microviscosity associated with a significative reduction in glucose disappearance rate (Rd), total body glucose disposal (TBGD), and nonoxidative glucose metabolism was found. In group D subjects (n = 10), all of these changes were correlated with one another. In a multiple regression analysis of the pooled data from all study subjects (n = 40), only plasma O2- production levels displayed a statistically significant relation with TBGD and nonoxidative glucose metabolism. In conclusion, in aged patients a significant relationship between free radical production and insulin action seems to exist.

Adult↗