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Purpose: To investigate the clinical efficacy of a "Universal Warming" protocol, based on subsequent steps with 1 M and 0.5 M concentration of extracellular cryoprotectant (ECCP), on shipped oocytes. Oocytes are vitrified using different brands of ready-to-use kits which recommend that the use of their own warming kit and combining different vitrification/warming kits may have legal consequences for assisted reproductive (AR) centers, until this practice has been validated with clinical studies. Methods: Retrospective multi-center transnational observational study. Number of oocytes warmed 1.898. Vitrification performed with vitrification kit (Kitazato, Japan); warming carried out randomly with two different kits: Kitazato warming kit and Vit Kit®-Thaw (FujiFilm Irvine, USA). Warmed oocytes were assigned to 2 groups: KK (Kitazato/Kitazato) 939, and KI (Kitazato/Irvine) 959. Primary endpoint: survival rate. Secondary endpoints: fertilization rate; blastulation rate; implantation rate; live birth rate. Results: Survival was comparable between the groups: 84.6% (795/939) in group KK vs 82.1% (787/959) in group KI. Fertilization rate was lower (P = 0.027) in group KK (75.7%—602/795) than in group KI (80.4%—633/787). Blastulation and implantation and live birth rates were all statistically comparable between the study groups: blastulation rate was 58.5% (352/602) vs 57.8% (366/633); implantation rate was 41.5% (80/193) vs 45.9% (84/183); live birth rate was 52.5% (62/118) in KK and 45.0% (54/120) in KI. Conclusion: The use of this "Universal Warming" protocol simplifies vitrified oocyte exchange between AR centers in different countries, and overcomes potential regulatory/commercial/availability differences affecting clinical practice. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The present study aimed at investigating the hyperglycaemic, lipolytic and ketogenic effects of small doses of glucagon delivered continuously or in a pulsatile manner. The study was performed in eight healthy young volunteers (24.2±1.2 years) and in eight healthy aged subjects (69.4±2.0 years). In all the subjects, endogenous pancreatic hormone secretion was inhibited by somatostatin and only glucagon was replaced. Consequently, the effects of pulsatile and continuous glucagon delivery were studied in conditions of progressive somatostatin-induced insulin deficiency. In both the young and the aged subjects, pulsatile glucagon delivery resulted in increases in plasma glucose, non-esterified fatty acid, glycerol and β-hydroxybutyrate levels greater than those observed when the same amount of glucagon was delivered in a continuous manner. The net increases in plasma glucose, glycerol and non-esterified fatty acid levels were similar between the young and the aged subjects when glucagon was infused continuously; in contrast, the rise in plasma β-hydroxybutyrate in the aged was only about half that observed in the young subjects. Surprisingly, when glucagon was infused in a pulsatile manner, the rises in plasma glycerol, non-esterified fatty acid and β-hydroxybutyrate levels were all significantly smaller in the aged subjects, while no significant differences were observed in the blood glucose responses. We conclude that, in the presence of somatostatin-induced insulin deficiency, pulsatile glucagon exerts greater effects on blood glucose, plasma non-esterified fatty acid, glycerol and β-hydroxybutyrate levels than its continuous delivery. In the elderly, the lipolytic and ketogenic, but not the hyperglycaemic, responses to pulsatile glucagon are significantly reduced. [ABSTRACT FROM AUTHOR]

Plasma and erythrocyte magnesium levels were measured by atomic absorption spectrometry in 12 healthy subjects and 12 moderately obese patients with Type 2 (non-insulin-dependent) diabetes mellitus. Basal plasma and erythrocyte magnesium levels were significantly lower in diabetic patients than in control subjects. In vitro incubation in the presence of 100 mU/l insulin significantly increased magnesium erythrocyte levels in both control subjects ( p<0.001) and patients with diabetes ( p<0.001). However, even in the presence of 100mU/l insulin, the erythrocyte magnesium content of patients with Type 2 diabetes was lower than that of control subjects. The in vitro dose-response curve of the effect of insulin on magnesium erythrocyte accumulation was shifted to the right when red cells of diabetic patients were used, with a highly significant reduction of the maximal effect. Such reduction of the maximal effect of insulin suggests that the impairment of insulin-induced erythrocyte magnesium accumulation observed in Type 2 diabetic patients results essentially from a post-receptor defect. In the diabetic patients, the Δ increase in erythrocyte magnesium levels (calculated as the net increase between basal and 100 mU/l insulin-induced erythrocyte magnesium levels) was negatively correlated with plasma insulin levels ( r=−0.86; p<0.001) and with body mass index ( r=−0.90; p<0.001); it was positively correlated with the glucose disappearance constant K after intravenous glucose injection ( r=0.79; p<0.01), with the amount of glucose required to keep euglycaemia despite hyperinsulinaemia in a glucose clamp ( r=0.88; p<0.001), and with the metabolic clearance rate of glucose during the clamp ( r=0.82; p<0.001). These results demonstrate that insulin-induced erythrocyte magnesium accumulation is impaired in patients with Type 2 diabetes and that such defect is correlated to impaired insulin-mediated glucose disposal in these patients. [ABSTRACT FROM AUTHOR]

We investigated the possible role of losartan on insulin-mediated glucose uptake, substrate oxidation and blood flow in insulin-resistant hypertensive patients. Sixteen newly diagnosed patients with mild-to-moderate hypertension were studied. The study design was a single-blind, randomised, placebo-controlled trial. After a 1 week run-in period, each patient was randomly assigned to placebo (n = 7) and losartan (n = 9). Both treatment periods lasted 4 weeks. At baseline, and at the end of the placebo and losartan treatment periods, euglycaemic hyperinsulinaemic glucose clamp and indirect calorimetry were performed. Before and along each glucose clamp, blood flow was also determined in the femoral artery by image-directed duplex ultrasonography combining B-mode imaging and pulse Doppler beams. Losartan vs placebo lowered systolic blood pressure by 163 ± 3.5 and 147 ± 4.1 mm Hg (P < 0.001), and diastolic blood pressure by 95 ± 3.2 and 85 ± 3.2 mm Hg (P < 0.001). Losartan enhanced glucose metabolic clearance rate by 5.1 ± 0.3 and 6.3 ± 0.4 mg/kg × min (P < 0.05), and whole body glucose disposal (WBGD) by 29.2 ± 0.5 and 38.1 ± 0.4 μmol/kg free fatty mass (FFM) 3 min (P < 0.01) but did not affect heart rate. Insulin-mediated change in blood flow was greater after losartan than placebo administration (111 ± 4 vs 84 ± 3%, P < 0.01). Per cent change in insulin-mediated stimulation of blood flow and WBGD were also correlated (r = 0.76, P < 0.01). Analysis of substrate oxidation revealed that losartan adminstration improved insulin action and non-oxidative glucose metabolism (NOGM) (30.8 ± 2.2 vs 22.8 ± 2.8 μmol/kg FFM × min, P < 0.05). In conclusion losartan improves insulin-mediated glucose uptake through an increase in NOGM and blood flow in hypertensive patients. [ABSTRACT FROM AUTHOR]

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 (PGI) analogue Iloporst (0.7 ng · kg · min). 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 μmol · kg LBM) and non-oxidative glucose metabolism (24.7 vs 18.1 μmol · kg LBM · min). 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 · min · kg), GU (0.55 vs 0.46 mmol · 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. [ABSTRACT FROM AUTHOR]

The effect of the calcium antagonist nicardipine on insulin secretion and glucose homoeostasis was investigated in elderly hypertensives with and without diabetes mellitus; 15 patients with essential hypertension for at least 10 years and normal glucose tolerance according to standard criteria (Group I) and 15 elderly hypertensive patients affected by Type 2 diabetes mellitus and on treatment with diet or oral drugs (Group 2). In the basal state, all patients were submitted to an oral glucose tolerance test (OGTT, 75 g) and an iv arginine test (30 g), on two different days and in random order. The same tests were repeated after one month of treatment with nicardipine 60 mg/day, in three spaced doses, the last being given 1 h before the post-treatment test. Nicardipine did not change overall glucose homoestasis, as assessed by haemoglobin Alc and fructosamine, nor did it significantly affect the plasma insulin response either to glucose or arginine in Groups 1 and 2. Only the glucagon response to arginine was significantly reduced in diabetic hypertensives. Small, non-significant variations in the metabolic and hormonal parameters were seen in additional two groups of patients (Groups 3 and 4), matched with Groups 1 and 2 for age, sex and diseases, who took capsules containing placebo. Thus, nicardipine did not produce any significant over-all alteration in glucose homoestasis when given to elderly diabetic or nondiabetic hypertensive subjects. [ABSTRACT FROM AUTHOR]

Twelve elderly non-insulin dependent diabetic patients took part in a double-blind, cross-over, randomized study comparing simvastatin 30 mg/day and placebo. Each treatment period lasted 3 weeks and was separated by a 3 week wash-out period. At the end of each treatment period all subjects underwent in randomized order an oral glucose tolerance test (OGTT; 75 g) and an euglycaemic hyperinsulinaemic (50 mU/kg·h) glucose clamp. Simvastatin compared to placebo significantly reduced plasma total cholesterol (7.9 vs 5.3 mmol·l), LDL-cholesterol (7.2 vs 4.3 mmol·l), triglycerides (2.9 vs 2.1 mmol·l), free fatty acids (1106 vs 818 mmol) and glucose (7.4 vs 6.6 mmol·l) levels. After simvastatin, and in the last 60 min of the glucose clamp, there was an improvement in the action of insulin as demonstrated by stronger inhibition of hepatic glucose output (2.7 vs 5.2 μmol·kg·min) and stimulation both of the glucose disappearance rate (26.3 vs 19.5 μmol·kg·min) and glucose metabolic clearance rate (4.3 vs 3.6 ml·kg·min). The changes in glucose turnover parameters were significantly correlated with basal plasma free fatty acids and were independent of plasma glucoregulatory hormones. In conclusion, simvastatin seems to exert beneficial effects both on lipid and glucose metabolism. [ABSTRACT FROM AUTHOR]

Sparteine sulphate, given i.v. as a bolus of 15 mg/ml plus 90 mg in 0.9% NaCl 100 ml over 60 min, increases plasma insulin and decreases plasma glucose and adrenaline in non-insulin dependent (Type II) diabetic subjects. The hypoglycaemic effect was also evident in the presence of a high plasma glucose level produced by Biostator changing glucose infusion from 20.2±2.8 to 26.4±4.2 mg · kg · min ( p<0.01), and it was potentiated by simultaneous infusion of arginine. No additional effect of sparteine on the peripheral sensitivity to insulin were detected by the euglycaemic, hyperinsulinaemic glucose clamp technique, as the glucose infusion rate (3.1±0.8 vs 2.6±1.2 mg · kg · min) was not statistically significant different in the last 60 min of the experiment. It is concluded that sparteine sulphate enhances β-cell secretion, causing a fall in the plasma glucose concentration. [ABSTRACT FROM AUTHOR]

Infusion of a therapeutic dose of sparteine sulphate, increased the basal plasma insulin level and lowered plasma glucose. When an intravenous glucose tolerance test was performed with the infusion, the total insulin AUC was significantly larger than in absence of sparteine (2025 vs 1464 µU/ml×min), plasma glucose levels were lower and improved glucose utilization was observed (k:1.55 vs 1.39%). In the presence of arginine, sparteine sulphate stimulated both β and α cells, increasing both the total insulin (1907 vs 1516 µU/ml×min p<0.02) and total glucagon AUCs (7616±654 vs 6789±707 pg/ml×min p<0.01). Thus, sparteine sulphate increased both basal and nutrient-induced insulin and glucagon secretion in normal man. [ABSTRACT FROM AUTHOR]

The effect of nifedipine, a calcium antagonist, on carbohydrate metabolism and insulin secretion was evaluated in patients who required treatment with this drug. 20 subjects underwent two oral glucose tolerance tests (100 g), one under basal conditions, and the other after ten days of treatment with nifedipine 30 mg/day by mouth, in three divided doses. 10 subjects had normal glucose tolerance; in them nifedipine administration reduced the insulin response to oral glucose in the first 60 min, but improved glucose tolerance. The other 10 subjects had impaired glucose tolerance and nifedipine treatment resulted in a further reduction both of insulin secretion and glucose tolerance. No such effects were seen in the placebo (weight- and disease-matched) group. The mechanism by which nifedipine influences carbohydrate metabolism and insulin secretion is discussed. [ABSTRACT FROM AUTHOR]