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The present volume, a collection of papers focusing on Venice and those former Venetian colonies which passed to the Ottoman Empire during the early Modern age, retraces the relationship between Venetians and Ottomans in terms of their economic and social history from the end of the XV to the XVIII century showing the permeability of the ruling forces of these two great empires within a continuous and changing stream.

Language private lessons became very popular during the 1990's especially in the countries I visited, as a language instructor: Russia and Turkey. Parallel to the constant increase in learning demand, a proliferation of instructors was registered; due to its apparently easy accessibility, the general impression is that in this field doesn’t exist a professional regulation; however it would be desirable to have this sector under control to satisfy the quality learning standards.In this paper the topic will be approached from different perspectives including the various implications it entails and the focus will be centred on some problems concerning language teaching in one-to-one classes, such as: students’ typology, curriculum implementation and learning/teaching continuity.

We describe an unusual case of hypoglycemic syndrome in a 69-year old woman with a proinsulin-only secreting pancreatic endocrine adenoma. The clinical history was highly suggestive of an organic hypoglycemia, with normal or relatively low insulin concentrations and elevated proinsulin levels. Magnetic resonance and computed tomography of the abdomen showed a 1 cm pancreatic nodule and multiple accessory spleens. The diagnosis was confirmed by selective angiography, showing location and vascularization of the nodule, despite no response to intra-arterial calcium. After resection, the hypoglycemic syndrome resolved. The surgical specimen was comprised of a neuroendocrine adenomatous tissue with high proinsulin immunoreactivity. Study of this unusual case of proinsulinoma underlines (i) the need to assay proinsulin in patients with hypoglycemia and normal immunoreactive insulin, (ii) the differential diagnosis in the presence of accessory spleens, (iii) the unresponsiveness to intra-arterial calcium stimulation, and (iv) the extensive evaluation needed to reach a final diagnosis.

The Zone diet (ZD) is centreed primarily on protein intake. Previous findings have assessed the role of ZD on glucose metabolism, but the outcomes have been conflicting. So far, there is no clear evidence of the effects of ZD on insulin response. Furthermore, the effect of ZD on insulin sensitivity has never been clearly determined yet. Our aim was to evaluate in healthy subjects how ZD acts on body composition, lipid profile and overall on insulin sensitivity and secretion in dynamic conditions. We also compared ZD effects with those of the Mediterranean diet (MD). Twelve volunteers were studied. Subjects were randomized either to MD or to ZD for 8 weeks. A wash-out period followed. Afterwards, subjects were crossed over to the other diet for other 8 weeks. At any end-point subjects underwent standard 75 g oral glucose tolerance test for measurements of glucose, insulin, C-peptide, proinsulin and glucagon. Lipids and free fatty acids were determined at fasting. Insulin sensitivity was assessed by the oral glucose insulin sensitivity index. Insulin secretion was determined by mathematical modelling of insulin and C-peptide data. No significant differences were observed following both diets in body weight, fat mass and plasma glucose, insulin, C-peptide, proinsulin and glucagon levels. Similarly, insulin sensitivity and secretion were not different in both absolute values and changes from baseline. Decrease in triglyceride and increase in HDL–cholesterol levels were observed after ZD compared with MD. Thus, it was determined that intake of high-protein diet for 2 months does not modify insulin action and secretion, but improves lipid profile.

Introduction: Cardio- and/or cerebro-vascular risk are associated with high lipoprotein (a) [Lp(a)] levels and low-molecular-weight (LMW) apo(a) isoforms. Aims of this study were to evaluate the deposition of apo(a) isoforms and apoprotein B (apo B) in atherosclerotic plaque from patients (males and females) who had carotid endarterectomy for severe stenosis, and to identify differences between patients classified by gender and divided according to the stability or instability of their plaques. Materials and methods: We determined lipids, apo B and Lp(a) in serum and plaque extracts from 55 males and 25 females. Apo(a) was phenotyped and isoforms were classified by number of kringle IV (KIV) repeats. Results: Lp(a) levels were higher in female serum and plaque extracts than in male samples, while apo B levels were lower. More Lp(a) than apo B deposition was observed in plaque after normalization for serum levels. Thirty-one different apo(a) isoforms were detected in our patients, with a double band phenotype in 94% of cases. In both sexes, the low/high (L/H) molecular weight apo(a) isoform expression ratio was significantly higher in plaque than in serum. Females with unstable plaques had higher Lp(a) levels in both serum and tissue extracts, and fewer KIV repeats of the principal apo(a) isoform in the serum than the other female group or males. Conclusions: In both sexes, the same apo(a) isoforms are found in serum and atherosclerotic plaque, but in different proportions: in plaque, LMW apo(a) is almost always more strongly accumulated than HMW apo(a), irrespective of any combination of apo(a) isoforms in double band phenotypes or Lp(a) serum levels. Moreover, serum and tissue Lp(a) levels were higher in females than in males, and particularly in the group with unstable plaques.

Background Our aim was to identify the pancreatic cancer diabetogenic peptide. Methods Pancreatic tumor samples from patients with (n = 15) or without (n = 7) diabetes were compared with 6 non-neoplastic pancreas samples using SDS-PAGE. Results A band measuring approximately 1500 Da was detected in tumors from diabetics, but not in neoplastic samples from non-diabetics or samples from non-neoplastic subjects. Sequence analysis revealed a 14 amino acid peptide (1589.88 Da), corresponding to the N-terminal of the S100A8. At 50 nmol/L and 2 mmol/L, this peptide significantly reduced glucose consumption and lactate production by cultured C2C12 myoblasts. The 14 amino acid peptide caused a lack of myotubular differentiation, the presence of polynucleated cells and caspase-3 activation. Conclusions The 14 amino acid peptide from S100A8 impairs the catabolism of glucose by myoblasts in vitro and may cause hyperglycemia in vivo. Its identification in biological fluids might be helpful in diagnosing pancreatic cancer in patients with recent onset diabetes mellitus.

Methionine is a sulfur-containing amino acid that is reversibly converted into homocysteine. Homocysteine is an independent cardiovascular risk factor frequently associated with the insulin resistance syndrome. The effects of insulin on methionine and homocysteine kinetics in vivo are not known. Six middle-aged male volunteers were infused with l-[ methyl-2H3,1-13C]methionine before (for 3 h) and after (for 3 additional hours) an euglycemic hyperinsulinemic (150 mU/l) clamp. Steady-state methionine and homocysteine kinetics were determined using either plasma (i.e., those of methionine) or intracellular (i.e., those of plasma homocysteine) enrichments. By use of plasma enrichments, insulin decreased methionine rate of appearance (Ra; both methyl- and carbon Ra) by 25% ( P < 0.003 vs. basal) and methionine disposal into proteins by 50% ( P < 0.0005), whereas it increased homocysteine clearance by ∼70% ( P < 0.025). With intracellular enrichments, insulin increased all kinetic rates, mainly because homocysteine enrichment decreased by ∼40% ( P < 0.001). In particular, transmethylation increased sixfold ( P < 0.02), transsulfuration fourfold ( P = 0.01), remethylation eightfold ( P < 0.025), and clearance eightfold ( P < 0.004). In summary, 1) physiological hyperinsulinemia stimulated homocysteine metabolic clearance irrespective of the model used; and 2) divergent changes in plasma methionine and homocysteine enrichments were observed after hyperinsulinemia, resulting in different changes in methionine and homocysteine kinetics. In conclusion, insulin increases homocysteine clearance in vivo and may thus prevent homocysteine accumulation in body fluids. Use of plasma homocysteine as a surrogate of intracellular methionine enrichment, after acute perturbations such as insulin infusion, needs to be critically reassessed.

The effect of 7 day continuous subcutaneous infusion of octreotide (200 microg day(-1)) was evaluated in seven insulin-pump treated Type 1 diabetic patients (age 43+/-1.5 year; BMI 25.1+/-0.7 kg m(-2); HbA(1c) 7.4+/-0.3%). A 24-h metabolic and hormonal profile, and a euglycaemic hyperinsulinaemic clamp (0.25, 0.5, 1.0 mg kg(-1) min(-1)), with [3H]glucose infusion and indirect calorimetry, were performed before and after a 7-day octreotide infusion. Mean 24-h plasma glucose was similar before and after octreotide (9.7+/-0.8 vs. 9.1+/-1.0 mmol l(-1)) but insulin requirement dropped by 45% (49+/-4 vs. 27+/-2 U day(-1); P0.01). Both 24-h plasma hGH and glucagon were suppressed by octreotide (1.85+/-0.35 vs. 0.52+/-0.04 microg l(-1), and 117+/-23 vs. 102+/-14 ng l(-1), respectively). Glucose utilisation increased after octreotide (insulin 0.5 mU kg(-1) min(-1) clamp 3.09+/-0.23 vs. 4.19+/-0.19 mg kg(-1) min(-1); 1 mU kg(-1) min(-1) clamp 5.64+/-0.61 vs. 7.93+/-0.57 mg kg(-1) min(-1); both P0.05) and endogenous glucose production was similarly suppressed. Glucose oxidation was not affected by octreotide, while the improvement in glucose storage (insulin 1.0 mU kg(-1) min(-1) clamp 3.89+/-0.60 vs. 5.64+/-0.67 mg kg(-1) min(-1), P0.05) entirely accounted for the increase in glucose disposal. Endogenous glucose production was more effectively suppressed at the two lower insulin infusion rates (P0.05). Energy expenditure declined after octreotide. Continuous subcutaneous octreotide infusion suppresses counterregulatory hormones, increases insulin-mediated glucose metabolism by enhancing glucose storage, and reduces energy expenditure. These results support a role for counterregulatory hormones in the genesis of insulin resistance and the catabolic state of Type 1 diabetes.

Several methods have been employed to measure the production of ketone bodies by the liver cells from precursors, such as free fatty acids. This study quantifies the kinetics of oleate (a free fatty acid) and the relative production of ketone bodies (acetoacetate arxi 3-hydroxybutyrate) by using a mathematical model. Experimental data were collected from perfusion experiments carried out in isolated rat hepatocytes. The model describes the dynamic behaviour of the three compounds in the perfusion medium in the presence of increasing doses (0.25, 0.50 and 1.00 mM) of oleic acid. It accounts for the disappearance of oleic acid by considering the conversion to ketone bodies and the degradation to other metabolic pathways. Because of identifiability problems the two ketone bodies could not be analyzed separately, thus their ratio has been considered. With the highest dose (1 mM), the fractional conversion of oleate to ketone bodies decreased raising the hypothesis of a saturative mechanism for the liver production of ketone bodies. This hypothesis was also supported by the unchanged degradation of oleate to other metabolic pathways, despite the marked change in the dose. In conclusion, this model allows inferences in the liver physiology of free fatty acids and ketone bodies without the need of radioactive tracers.

Epinephrine (EPI) plays a pivotal role in regulating glucose metabolism both in splanchnic and peripheral tissues. Nevertheless, previous studies did not clarify the mechanisms by which EPI affect both glucose disposal processes in peripheral tissues and β-cell secretion. The aim of this study was to investigate, in six normal volunteers, the effects of elevated EPI concentration on peripheral glucose disposal and insulin secretion by using the stable labeled (either [6,6-2H2] or [2-2H1]glucose) intravenous glucose tolerance test (IVGTT) in conjunction with the minimal models of labeled glucose disappearance and C-peptide secretion. Elevated plasma EPI concentration significantly decreased glucose effectiveness (SG*) by 29% (0.0059 ± 0.0013 vs. 0.0083 ± 0.0011 min−1, P < 0.05), and even more, 61%, insulin sensitivity (SI*); (22 ± 6 · 10(4) vs. 54 ± 20 · 10(4) min−1.pmol.l−1; P < 0.01). These findings are not due to an isotopic effect induced by an enhanced glycogen breakdown, because the [2-2H1]glucose tracer, which is not incorporated into glycogen, gave results similar to those of [6,6-2H2]glucose tracer. No differences were observed in first phase cell sensitivity, phi 1, in the EPI study (199 ± 91 vs. 245 ± 144 10(9), NS), but there was a significant increase in the second-phase cell sensitivity to glucose phi 2, (15.2 ± 1.7 vs. 17.7 ± 4.4 10(9).min−1, P < 0.05). In conclusion, EPI selectively impairs peripheral glucose metabolism because of its unique ability to simultaneously and independently decrease glucose effectiveness and insulin sensitivity. Furthermore, EPI enhances phi 2, the ratio between the C-peptide amount secreted during the second phase and the area under the curve of the glucose signal, indicating that the observed increase of C-peptide concentration is due not only to the augmented glucose signal but also to a specific EPI-mediated enhancement of β-cell responsivity to glucose.

After isolating NT-S100A8 from pancreatic cancer (PC) tissue of diabetic patients, we verified whether this peptide alters PC cell growth and invasion and/or insulin release and [Ca(2+)](i) oscillations of insulin secreting cells and/or insulin signaling. BxPC3, Capan1, MiaPaCa2, Panc1 (PC cell lines) cell growth, and invasion were assessed in the absence or presence of 50, 200, and 500 nM NT-S100A8. In NT-S100A8 stimulated beta-TC6 (insulinoma cell line) culture medium, insulin and [Ca(2+)](i) were measured at 2, 3, 5, 10, 15, 30, and 60 min, and [Ca(2+)](i) oscillations were monitored (epifluorescence) for 3 min. Five hundred nanomolars NT-S100A8 stimulated BxPC3 cell growth only and dose dependently reduced MiaPaCa2 and Panc1 invasion. Five hundred nanomolars NT-S100A8 induced a rapid insulin release and enhanced beta-TC6 [Ca(2+)](i) oscillations after both one (F = 6.05, P < 0.01) and 2 min (F = 7.42, P < 0.01). In the presence of NT-S100A8, [Ca(2+)] in beta-TC6 culture medium significantly decreased with respect to control cells (F = 6.3, P < 0.01). NT-S100A8 did not counteract insulin induced phosphorylation of the insulin receptor. Akt and I kappa B-alpha, but it independently activated Akt and NF-kappa B signaling in PC cells. In conclusion, NT-S100A8 exerts a mild effect on PC cell growth, while it reduces PC cell invasion, possibly by Akt and NF-kappa B signaling, NT-S100A8 enhances [Ca(2+)](i) oscillations and insulin release, probably by inducing Ca(2+) influx from the extracellular space, but it does not interfere with insulin signaling.

In this study, we assessed the effects of alcohol intake on glucose counterregulation in response to acute insulin-induced hypoglycemia in IDDM patients and in normal control subjects. Nine euglycemic IDDM patients and 9 normal control subjects were studied. After a baseline period, insulin (0.15 U/kg) was administered subcutaneously to induce hypoglycemia. Each IDDM patient was studied 3 times. In the first study, alcohol was orally administered as wine. In the second (control) study, water was administered instead of wine. In the third study, wine was given; however, a continuous infusion of heparin plus intralipid was administered to prevent the fall in plasma free fatty acid. Normal control subjects underwent only the alcohol and the control studies. In IDDM patients alcohol intake impairs, whereas in normal subjects it supports glucose counterregulation. Alcohol intake is associated with normal catecholamine responses in both IDDM diabetic patients and normal subjects. In both IDDM patients and normal subjects, hepatic glucose production in the recovery phase of the alcohol study was normal. Plasma glucose rate of disappearance was significantly increased by alcohol intake in IDDM (13.72 ± 0.82 vs. 11.84 ± 0.53 μmol · kg−1 · min−1; P < 0.05). Alcohol intake in both normal subjects and IDDM patients decreased plasma free fatty acid (267 ± 22 vs. 156 ± 20 μM; P < 0.01 and 356 ± 29 vs. 96 ± 12 μM; P < 0.01). We hypothesized that in IDDM patients, deficient glucose recovery during alcohol intake is the result of the ability of alcohol to depress lipolysis.

The effects of two different plasma glucose concentrations (5 and 10 mmol/L) on lipolysis and ketogenesis during baseline and in response to epinephrine infusion were evaluated in insulin-dependent diabetic patients. Each insulin-dependent diabetic subject was studied during euglycemia, hyperglycemia with hypoinsulinemia, and hyperglycemia with hyperinsulinemia. Total ketone body (TKB) concentrations were significantly higher in hyperglycemic-hypoinsulinemic diabetics than in hyperglycemic-hyperinsulinemic and normoglycemic diabetics. Hyperglycemic-hyperinsulinemics had higher TKB concentrations than euglycemic diabetics. During epinephrine infusion, the ketone body rate of appearance and concentration significantly increased in all groups. Plasma FFA concentrations were significantly higher in hyperglycemic-hypoinsulinemic diabetics than in the other groups. During epinephrine infusion, the plasma FFA rate of appearance and concentration significantly increased in all groups. The apparent fraction of FFA converted to ketones was increased by epinephrine in all groups, except in hyperglycemic-hyperinsulinemic diabetics. In conclusion, this study demonstrates that although insulin alone decreases FFA and TKB concentrations, it does not affect the fraction of FFA converted to ketones. If hyperinsulinemia is superimposed on hyperglycemia, there is both a reduction of ketogenesis capacity, compared to hyperglycemia alone, and a decrease in the apparent fraction of FFA converted to ketone bodies.

We assessed the metabolism of the two KBs, AcAc and 3-BOH; the relationships between ketogenesis and FFA inflow rate; and the effect of chronic sulfonylurea treatment in mild NIDDM patients (plasma glucose < 10 mM). We studied 10 nonobese NIDDM patients in a crossover, randomized, double-blind, placebo-controlled fashion. Each patient was studied 4 times: after a run-in period with placebo, after 3 mo of placebo treatment, after 3 mo of glibenclamide treatments, respectively, and after 3 mo of sulfonylurea treatment during an acute exogenous Intralipid infusion. Ten normal, nondiabetic subjects served as the control group. Glibenclamide treatment decreased plasma FFAs. When these substrates were exogenously increased, plasma FFAs were comparable with placebo and baseline concentrations. In NIDDM patients, baseline and placebo blood total KB concentration was significantly higher than in control subjects (216 ± 22 and 244 ± 25, respectively vs. 127 ± 18 μM; P < 0.01). Glibenclamide treatment significantly decreased total KBs to 177 ± 19 μM (P < 0.05). When FFAs were exogenously increased, total KBs were similar to the placebo and baseline period. In the baseline study, the AcAc/3-BOH ratio was 0.72 ± 0.06 in control subjects, whereas in NIDDM patients, the ratio was 1.61 ± 0.13 at baseline (P < 0.001 vs. control subjects), 1.66 ± 0.15 during placebo, 1.57 ± 0.09 during glibenclamide (NS vs. baseline), and 1.51 ± 0.23 during glibenclamide plus placebo FFAs. Both the AcAc interconversion rate to 3-BOH and the 3-BOH interconversion rate to AcAc were significantly lower in NIDDM patients than in control subjects. In conclusion, in NIDDM patients the major portion of overall ketogenesis must be ascribed to AcAc production. 3-BOH production is decreased because of an impaired interconversion between the two ketones. A direct effect of glibenclamide on ketogenesis in vivo is disputable because blood KB concentrations increase to a similar extent for a given plasma FFA concentration in the presence or absence of this drug.

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 ofage 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/dl, E: 88 ± 3, p >0.1; Y: 50 ± 7 pM, E: 36 ± 7, p >0.05). Glucoseinsulin 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 lO-4min-1/(μU/ml), E: 7.11 ± 0.72, p > 0.1; SG = Y: 0.020 ± 0.003 min-1, E: 0.019 ± 0.002, p > 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 0.1), thus the changes in peripheral C-peptide concentration with age are likely to be due only to an altered beta-cell secretion. In particular, the total amount of secreted insulin during 240 minutes was reduced by ∼44% (Y: 7.7 ± 1.1 103 pM vs E: 4.3 ± 0.5, p < 0.01). This study indicated that healthy elderly subjects maintain a glucose disposal comparable to that of young controls. Nevertheless, when C-peptide patterns are analyzed, beta-cell activity appears altered with age. (Aging 2: 277-282,1990)

Although hyperhomocysteinemia, an independent cardiovascular risk factor, is common in type 2 diabetes with nephropathy, the mechanism(s) of this alteration is not known. In healthy humans, hyperinsulinemia increases methionine transmethylation, homocysteine transsulfuration, and clearance. No such data exist in type 2 diabetes either in the fasting state or in response to hyperinsulinemia. To this purpose, seven male type 2 diabetic patients with albuminuria (1.2 ± 0.4 g/day, three with mild to moderate renal insufficiency) and seven matched control subjects were infused for 6 h with l-[methyl-2H3, 1-13C]methionine. Methionine flux, transmethylation, and disposal into proteins as well as homocysteine remethylation, transsulfuration, and clearance were determined before and after euglycemic hyperinsulinemia (∼1,000 pmol/l). In type 2 diabetic subjects, homocysteine concentration was twofold greater (P < 0.01) and methionine transmethylation and homocysteine clearance lower (from ∼15 to >50% and from ∼40 to >100%, respectively; P < 0.05) than in control subjects. The insulin-induced increments of methionine transmethylation, homocysteine transsulfuration, and clearance were markedly reduced in type 2 diabetic subjects (by more than threefold, P < 0.05 or less vs. control subjects). In contrast, methionine methyl and carbon flux were not increased in the patients. In conclusion, pathways of homocysteine disposal are impaired in type 2 diabetes with nephropathy, both in postabsorptive and insulin-stimulated states, possibly accounting for the hyperhomocysteinemia of this condition.

Homocysteine is an independent risk factor for cardio- and/or cerebrovascular diseases. Many methods are used to measure plasma homocysteine levels in physiological fluids. Current gas chromatographic/mass spectrometric (GC/MS) methods allow determination not only of plasma homocysteine concentration, but also of its turnover. However, they have some methodological limitations due to the reduction of disulfide bonds between homocysteine and other thiols or proteins often requiring the use of several very toxic compounds or multi-step procedures that are particularly time-consuming, and/or utilize expensive instruments. Herein is described a rapid and precise GS/MS method to determine homocysteine turnover from a relatively low volume of plasma (200 microL). First disulfide bonds were reduced by 2-mercaptoethanol, which allows the maintenance of the reduced status preventing the rebuilding of the disulfide bond. Then the sample was derivatized to form the bis-tert-butyldimethylsilyl derivative. A deuterated internal standard, DL-[3,3,3',3',4,4,4',4'-2H8]-homocystine, was employed to account for losses associated with each analytical step. To evaluate the 'in vivo' homocysteine metabolic turnover, [1-13C]-methionine was infused and the derived [1-13C]-homocysteine quantitated. So a standard curve of [1-13C]-homocysteine was prepared by the decomposition of the [1-13C] methionine. The ions at m/z 325 and 326 were monitored, corresponding to the unlabeled [12C]-homocysteine and to labeled [13C]-homocysteine, respectively. The ion at m/z 325 ([M-114)]+) probably resulted from the loss of one derivatizing group to regenerate a free amino group. The intra-assay coefficient of variation (CV-intra%) was consistently less than 1.06%, the inter-assay (CV-inter%) less than 1.05%. The method described here seems to be simpler, more rapid, and less toxic than those published so far. In particular, its main strength appears to be the degree of precision obtained. We suggest applying this method to the measurement of the 'in vivo' rate of production of homocysteine (by the plasma 13C-homocysteine enrichment) from its precursor (13C-methionine).

The aim of this study is the characterization, by means of mathematical models, of the activity of isolated hepatic rat cells as regards the conversion of free fatty acids (FFA) to ketone bodies (KB). A new physiologically based compartmental model of FFA metabolism is used within a context of population pharmacokinetics. This analysis is based on a hierarchical model, that differs from standard model formulations, to account for the fact that some data sets belong to the same animal but have been collected under different experimental conditions. The statistical inference problem has been addressed within a Bayesian context and solved by using Markov Chain Monte Carlo (MCMC) simulation. The results obtained in this study indicate that, although hormones epinephrine and insulin are important metabolic regulatory factors in vivo, the conversion of FFA to KB by isolated hepatic rat cells is not significantly affected by epinephrine and only little influenced by insulin. So we conclude that in vivo, the interaction of these two hormones with other compounds not considered in this study plays a fundamental role in ketogenesis. From this study it appears that mathematical models of metabolic processes can be successfully employed in population kinetic studies using MCMC methods. © 2003 Biomedical Engineering Society. PAC2003: 8716Ac, 8715Rn, 8715Nn

Pancreatic adenocarcinoma causes diabetes mellitus by releasing factors interfering with glucose metabolism.We verified in isolated rat hepatocytes the molecular weight (MW) of the fraction from pancreatic cancer cell conditioned media (CM) that altered glucose metabolism and ascertained, using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis, whether there is any common peptide in CM and in the sera of patients with pancreatic cancer.Sera was obtained from patients with pancreatic cancer ( n = 14) and chronic pancreatitis ( n = 9) and healthy control subjects ( n = 10). Conditioned medium (CM) was obtained from the following cell lines: MIA PaCa 2, PSK-1, PANC-1, and CAPAN-1. Two fractions (MW of less than 30,000 Da and less than 10,000 Da) were obtained from patients' sera, from CM, and from non-CM (NCM) after two-step ultrafiltration. Rat hepatocytes were incubated with CM and NCM. The peptide profile of patients' sera, CM, and NCM were analyzed using MALDI-MS.In rat hepatocytes, glucose metabolism was impaired by CM from all the pancreatic cancer cell lines and by CM with an MW of less than 10,000 Da. Two peptides (m/z 2030 and 2726) were found in CM and patients' sera. Only the peptide at m/z 2030 was found to be associated with the presence of diabetes.A peptide at m/z 2030 may be a putative pancreatic cancer-associated diabetogenic factor.

BackgroundBecause of advances in knowledge over recent years there is reason to believe that surgical attitudes towards patients with chronic pancreatitis may have changed.MethodsSome 547 patients were treated surgically for chronic pancreatitis from 1971 to June 1998. Anastomoses were performed in 80 per cent (438 patients) and resections in 20 per cent (109 patients). Indications and type of operation were analysed, as were mortality and morbidity rates and long-term follow-up results, in patients undergoing resection both over the period as a whole and after dividing the series into two subperiods of 14 years.ResultsIn the second 14-year period, there was a significant reduction in the percentage of resections compared with anastomoses (28 per cent (69 of 244 patients) versus 13 per cent (40 of 303); P < 0·0001), and a significant change in the type of resection with a substantial increase in resections of the head compared with those of the body and tail. Statistically significant reductions occurred in operating times, number of units of blood transfused (mean(s.d.) 4·7(3·6) versus 1·2(1.6) units; P = 0·0001) and mean hospital stay (18 versus 14 days for pylorus-preserving and 12 versus 8 days for left pancreatectomy with splenectomy; P < 0·01); mortality and morbidity rates also tended to decrease, but not significantly.ConclusionA different pattern has emerged over the years as regards both the type and number of resections performed.

A serious insulin resistance characterizes pancreatic cancer-associated diabetes mellitus. Elsewhere, we demonstrated that MIA PaCa2 cultured cells secrete a soluble factor responsible for reduced glucose tolerance induced in SCID mice. The intracellular mechanism of insulin resistance was investigated in isolated and perfused rat hepatocytes incubated with MIA PaCa2 conditioned medium. Lactate production was reduced compared to hepatocytes incubated with control medium while 1,2-DAG was increased and PKC was activated in the hepatocytes incubated with MIA PaCa2 conditioned medium. This behavior was not reproduced treating the hepatocytes with the growth factors EGF, interleukin Iβ, interleukin-6, and TGF-β1. In an attempt to make a biochemical identification of the hypothesized tumor associated-diabetogenic factors we observed a low molecular weight protein in the conditioned medium, absent in the nonconditioned one, that may be responsible for the described behaviors.

We determined whether ethanol (ETOH) directly stimulates ketogenesis, and the fraction of ETOH disposed to ketone bodies (TKB), in humans. Five volunteers participated in two studies in random order. In protocol 1, an infusion of D-(-)3hydroxy[1,2,3,4- 13 C 4 ]butyrate and [1,3- 13 C 2 ]acetoacetate before and during a continuous infusion of either ETOH or saline was administered; in protocol 2, an infusion of [2- 13 C 1 ]ethanol was administered. In protocol 1 ETOH (12.7±1.2 mM) produced an increase in blood 3-hydroxybutyrate (3-BOH) levels from 28±5 μM to 76±7 (p 13 C 1 ]ethanol infusion, the [13C1]3-BOH[12C]3-BOH ratio increased from a baseline value of .0832 to 0.4224 while the the [13C1]AcAc[12C]AcAc ratio from 0.9081 to 0.3505 for [ 13 C]AcAc. From the mass tracer balance equations the estimated fraction of ETOH disposed via KB route was 2.08±0.15%. In conclusion this study demonstrates that: A) The ketogenetic effect of ETOH can be quantified, in humans; B) ETOH exerts a direct ketogenic effect in humans; C) the fraction disposed via this route is small in normal humans after an overnight fast.

In this study we assessed whether conditioned media from a human pancreatic cancer cell line (MIA PaCa 2) can interfere with some intracellular pathways involved in glucose metabolism in isolated rat hepatocytes. The hepatocytes, isolated from Male Wistar rats, were incubated with MIA PaCa 2-conditioned or nonconditioned media. Conditioned and nonconditioned hepatocytes were run for 120 min in the presence or absence of insulin (100 mM) and were sampled at fixed time intervals. Supernatant glucose levels decreased to a similar extent over time in both conditioned and nonconditioned hepatocytes, while lactate levels significantly increased in nonconditioned hepatocytes with respect to conditioned hepatocytes. A pyruvate kinase activity increase was observed only in nonconditioned hepatocytes and was biphasic in nature, since this increased activity was detected both after a few and after 30 min following insulin stimulation. The cyclic AMP level increase was significantly higher in conditioned than in nonconditioned hepatocytes. It appears that MIA PaCa 2 cells produce a factor(s) that may interfere with one of the insulin-mediated intracellular pathways of glucose metabolism, namely, glycolysis. This detrimental effect on glycolysis is supported by the blunted rise in lactate concentration in the medium after the glucose challenge. This substance(s) probably transfers its signal inside the target cells, activating the adenylate cyclase pathway. These results support the hypothesis that pancreatic cancer is the cause rather than the consequence of diabetes mellitus.

The effect of ethanol (ETOH) on muscle metabolism was assessed in both normal (NC) and noninsulin-dependent (NIDDM) subjects in the basal state and during isoglycemic hyperinsulinemia (450 pmol/L) clamp studies carried out either with systemic (NC, n = 5; NIDDM, n = 5) or intrabrachially (NC, n = 5; NIDDM, n = 5)ETOH infusion. On a repeat study, each subject underwent the same experimental procedures, except that saline was infused instead of ETOH. Systemic ETOH significantly decreased whole body glucose disposal in both NC and NIDDM patients. In NC, ETOH infusion decreased basal forearm glucose uptake (FGU) from 1.22 +/- 0.20 to 0.32 +/- 0.04 mumol/min.100 mL tissue (P0.01), whereas in NIDDM, this decrement was not significant (from 0.95 +/- 0.31 to 0.66 +/- 0.23). With saline infusion, hyperinsulinemia significantly stimulated FGU to 4.09 +/- 0.46 mumol/min.100 mL tissue in NC and to 2.50 +/- 0.76 in NIDDM. During ETOH, FGU was depressed by 81% in NC (delta = 3.32 mumol/min.100 mL tissue) and by 48% (P0.05) in NIDDM (delta = 1.21 mumol/min.100 mL tissue). Local ETOH infusion did not affect FGU in either NC (1.18 +/- 0.23 vs. 1.1 +/= 0.11 mumol/min.100 mL tissue in the baseline condition and 4.12 +/- 0.65 vs. 3.97 +/- 0.35 in insulin-stimulated conditions) or NIDDM (1.05 +/- 0.29 vs. 1.1 +/- 0.19 mumol/min.100 mL tissue in baseline condition and 2.72 +/- 0.82 vs. 2.83 +/- 0.51 in insulin-stimulated conditions) subjects. With systemic ETOH, but not local infusion, there was a reduction in baseline plasma free fatty acid level and an increase in blood lactate concentration during isoglycemic hyperinsulinemia. In summary, systemic ETOH infusion impairs both whole body and forearm glucose uptake in NC and NIDDM subjects; this effect was more apparent in NC than in NIDDM at both the whole body and forearm level. On the contrary, intrabrachial ETOH infusion did not affect forearm glucose balance in either group. These results suggest that the reduction in muscle glucose disposal associated with increased systemic ETOH concentrations is not caused by a direct ETOH effect on muscle glucose metabolism.

Assessment of insulin sensitivity in subjects with non-insulin-dependent diabetes mellitus (NIDDM) is of paramount importance but intrinsically difficult. The standard (hereafter cold) minimal model, in conjunction with an insulin-modified protocol, has been recently proposed, but the estimates of insulin sensitivity showed poor precision (Saad et al. Diabetes 43: 1114-1121, 1994). We propose the tracer (hereafter hot) minimal model as a highly reliable method to estimate insulin sensitivity (SI*) and fractional glucose clearance (SG*), reflecting glucose disposal only, in NIDDM subjects. A [6,6- 2H2] glucose-labeled insulin-modified intravenous glucose tolerance test was performed in seven NIDDM subjects. In particular, SI* was 1.07 +/- 0.34 x10(-4)min(-1).microU-1.ml estimated with an average precision (mean coefficient of variation of 12%, range 4-22%), whereas the cold minimal model SI was 0.96 +/- 0.26 x 10(-4) min-1. microU-1.ml (mean coefficient of variation of 105%, range 3-353%). Another advantage of the hot indexes with respect to the cold indexes is their ability to reflect glucose and insulin effect on glucose disposal only, and not also on hepatic glucose production. Finally, we also studied by simulation the effect of glucose urinary loss on cold and hot minimal model indexes; only cold glucose effectiveness (SG) was significantly affected, resulting in a mean approximately 40% lower. The hot minimal model appears therefore more reliable than the cold model for assessing glucose tolerance in NIDDM subjects. In particular its ability to dissect disposal from production processes, coupled with the very good precision of the estimated metabolic indexes, supports the clinical use of this method in NIDDM subjects.

OBJECTIVE To test whether a suppertime injection of human ultralente insulin in patients with type I diabetes would result in a larger inhibition of basal hepatic glucose production (HGP) and improvement in fasting and mean daily plasma glucose levels. RESEARCH DESIGN AND METHODS We studied 16 type I diabetic patients (41 ± 4 years of age; body mass index [BMI] = 23.3 ± 0.3 kg/m2; diabetes duration >3 years) with a crossover protocol of therapy with an intermediate and ultralente insulin. All patients were already treated with three injections per day of regular insulin in addition to intermediate-acting (NPH) insulin at suppertime. After a 14-day run-in period, patients were randomly assigned to treatment with equivalent doses (10.8 ± 0.8 U, at 1900) of intermediate (Humulin 1) or ultralente (Humulin U) insulin. After 1 month of treatment, patients were crossed over. No change of the insulin dosage was performed during the study period. Basal HGP was measured by β-glucose infusion. Plasma glucose concentration was measured in the fasting state and monitored during the day. RESULTS Before starting the study period, fasting plasma glucose was 13.4 ±1.1 mM and plasma free-insulin was 48.0 ± 4.8 pM. Daily plasma glucose concentration averaged 10.3 ± 0.3 mM and the area under the curve (AUC) was 1.41 ± 0.05 mol/14 h. NPH insulin, given at suppertime for a month, did not induce significant changes in fasting plasma insulin (40.2 ± 4.8 pM), glucose concentration (14.0 ± 0.9 mM) or HGP (20.2 ± 2.2 jamol · kg–1 · min–1). Accordingly, no change occurred in the average daily plasma glucose (10.3 ± 0.3 mM) or AUC (1.41 ± 0.9 mol/14 h). Glycated hemoglobin also was not affected (8.2 ± 0.4 vs. 8.2 ± 0.3%). On the contrary, a 4-week treatment with ultralente insulin, also given at suppertime, was associated with a decline in the basal HGP (16.0 ±1.3 /Ltmol · kg–1 · min–1), fasting (11.3 ± 0.9 mM) and average daily (9.4 ± 0.3 mM) plasma glucose concentrations, and AUC (1.29 ± 0.07 mol/14 h) of plasma glucose level (all P < 0.05). Glycated hemoglobin was reduced (7.9 ± 0.4%). In each condition, fasting plasma glucose concentration was correlated with the average daily plasma glucose level (basal = 0.78; intermediate = 0.89; ultralente = 0.62; all P < 0.05), which suggests that ultralente insulin likely induces the improvements of metabolic control through reducing fasting plasma glucose. CONCLUSIONS Our results suggest that treating type I diabetic patients with ultralente insulin at suppertime provides a better modulation of basal HGP so that lower fasting plasma glucose levels are ensured. The reduction of fasting hyperglycemia is likely to affect positively aily plasma glucose control.

This study was performed to verify: (1) the ability of different insulin concentrations to restrict the lipolytic and ketogenic responses to exogenous epinephrine administration; (2) whether the ability of insulin to suppress the lipolytic and ketogenic responses during epinephrine administration is impaired in Type 1 (insulin-dependent) diabetic patients. Each subject was infused on separate occasions with insulin at rates of 0.2, 0.4, and 0.8 mU.kg-1.min-1 while normoglycaemic. To avoid indirect adrenergic effects on endocrine pancreas secretions, the so-called "islet clamp" technique was used. Rates of appearance of palmitic acid, acetoacetate, and 3-hydroxybutyrate were simultaneously measured with an infusion of 13C-labelled homologous tracers. After a baseline observation period epinephrine was exogenously administered at a rate of 16 ng.kg-1.min-1. At low insulin levels (20 microU/ml) the lipolytic response of comparable magnitude was detected in normal and Type 1 diabetic patients. However, the ketogenic response was significantly higher in Type 1 diabetic patients. During epinephrine administration, similar plasma glucose increments were observed in the two groups (from 4.74 +/- 0.53 to 7.16 +/- 0.77 mmol/l (p less than 0.05) in Type 1 diabetic patients and from 4.94 +/- 0.20 to 7.11 +/- 0.38 mmol/l (p less than 0.05) in normal subjects, respectively). At intermediate insulin levels (35 microU/ml) no significant differences were found between Type 1 diabetic patients and normal subjects, whereas plasma glucose levels rose from 4.98 +/- 0.30 to 6.27 +/- 0.66 mmol/l (p less than 0.05) in Type 1 diabetic patients, and from 5.05 +/- 0.13 to 6.61 +/- 0.22 mmol/l (p less than 0.05) in normal subjects. At high insulin levels (70 microU/ml) the lipolytic response was detectable only in Type 1 diabetic patients; the ketogenic response was reduced in both groups. During the third clamp, a significant rise in plasma glucose concentration during epinephrine infusion was observed in both groups. In conclusion this study shows that at low insulin levels Type 1 diabetic patients show an increased ketogenic response to epinephrine, despite their normal nonesterified fatty acid response. Instead, high insulin levels are able to restrict the ketogenic response to epinephrine in both normal and Type 1 diabetic subjects, although there is a still detectable lipolytic response in the latter. In the presence of plasma free insulin levels that completely restrict the ketogenic response in the same group, there is still a distinct glycaemic response. Plasma insulin levels in Type 1 diabetic patients are a major determinant of the metabolic response to epinephrine.

To estimate whole body and splanchnic metabolism of dietary amino acids, phenylalanine and leucine kinetics were determined simultaneously in six normal volunteers before and during the constant administration of a complete mixed meal, employing multiple tracers of these amino acids. L-[5,5,5-2H]leucine and L-[2,6-3H]-phenylalanine were infused intravenously; L-[1-13C]leucine and L-[1-14C]phenylalanine were administered orally with the meal. During the meal, steady-state leucine concentration rose from 136 +/- 6 to 190 +/- 14 mumol/l (P less than 0.01), phenylalanine from 44 +/- 4 to 61 +/- 6 mumol/l (P less than 0.01), total leucine rate of appearance (Ra) from 1.29 +/- 0.03 to 1.77 +/- 0.07 (P less than 0.01, +37 +/- 3%), and phenylalanine Ra from 0.73 +/- 0.05 to 0.80 +/- 0.07 mumol.kg-1.min-1 (P less than 0.05, +8 +/- 3%). Splanchnic uptake of dietary phenylalanine was greater (P less than 0.001) than that of leucine (58 +/- 4 vs. 25 +/- 4%, respectively), 44 +/- 3% of circulating leucine derived from the diet vs. 20 +/- 2% of circulating phenylalanine (P less than 0.01). Endogenous leucine and phenylalanine Ra were significantly suppressed (P less than 0.05). In summary: 1) splanchnic uptake of dietary phenylalanine is onefold greater than that of leucine; 2) dietary contribution to systemic phenylalanine Ra is about half of that to leucine Ra; and 3) endogenous appearance of both leucine and phenylalanine after the meal is suppressed. In conclusion, splanchnic metabolism of dietary leucine and phenylalanine differs markedly and can be quantitated in vivo without catheterization.

Isotope dilution studies of ketone body (KB) turnover have usually been performed using a single 14C tracer and the so called 'combined KB specific activity'. By definition, this approach does not allow to evaluate the individual kinetics of acetoacetate (AcAc) and 3-hydroxybutyrate (R-BHB) which is feasible only using the separate administration of 14C tracer AcAc and R-BHB. In the present study we followed a different approach using the simultaneous administration in vivo of [1,2,13C2] AcAc and m [1,2,3,4(13)C4] R-BHB which allows to evaluate the individual kinetics of the two KB in the some study, thus minimizing the magnitude of blood sampling and the potential changes in the metabolic conditions of each subject. The four isotopic 13C/12C KB ratios of AcAc and R-BHB tracer and tracee blood concentrations along with the fluorimetric measurement of 12C concentrations were determined in each blood sample. Using compartmental analysis following single dose bolus injection the production rate of KB was 206 +/- 57 mumol/min/1.73 m2 (mean +/- SD). The turnover rate of KB using noncompartmental analysis, during continuous infusion in a separate study was 294 +/- 41. The plasma clearance rates of AcAc and R-BHB were 1966 +/- 502 and 1443 +/- ml/min/1.73 m2, respectively. The mean residence time was 17 +/- 3 min and the total distribution volume 20 +/- 9.7 l/m2. We conclude that: (1) stable isotope tracer infusion allows the contemporary in vivo administration of the two KB and the simultaneous assessment of individual AcAc and R-BHB kinetics; (2) the estimated compartmental and noncompartmental parameters of KB turnover were similar to those observed in normal overnight fasting subjects following separate radioactive tracer injections.

Euglycemic insulin glucose-clamp and insulin-binding studies on erythrocytes and monocytes were performed in seven type II (non-insulin-dependent) diabetic subjects before and after 4 wk of metformin treatment (850 mg 3 times/day) and in five obese subjects with normal glucose tolerance. Glucose turnover was also measured at basal insulin concentrations and during hyperinsulinemic euglycemic clamps. During euglycemic insulin-glucose clamps, diabetic subjects showed glucose disposal rates of 3.44 ± 0.42 and 7.34 ± 0.34 mg · kg−1 · min−1 (means ± SD) before metformin at insulin infusion rates of 0.80 and 15.37 mU · kg−1 · min−1, respectively. With the same insulin infusion rates, glucose disposal was 4.94 ± 0.55 (P < .01) and 8.99 ± 0.66 (P < .01), respectively, after metformin treatment. Glucose disposal rates in normal obese subjects were 5.76 ± 0.63 (P < .01) and 10.92 ± 1.11 (P < .01) at 0.80 and 15.37 mU · kg−1 · min−1, respectively. Insulin maximum binding to erythrocytes in diabetics was 9.6 ± 4.2 and 5.8 ± 2.6 × 109 cells (means ± SD) before and after metformin treatment, respectively (NS). Insulin maximum binding to monocytes in diabetics was 6.2 ± 2.3 × 107 cells before and 5.0 ± 1.6% after metformin. Hepatic glucose production was higher in the diabetic patients at basal insulin levels, but not at higher insulin concentrations, and was not significantly changed by drug treatment. Basal glucose and insulin concentrations decreased with metformin. Thus, metformin treatment improved glucose disposal rate without significant effect on insulin-binding capacity on circulating cells. Basal hepatic glucose output was slightly lower after metformin treatment in view of lower (9 vs. 15 μU/ml) insulin levels, potentially indicating increased sensitivity of the liver to insulin.

We evaluated the in vivo biological activity of in vitro extensively glycosylated insulin (GI) with the euglycemic-hyperinsulinemic glucose-clamp technique in postabsorptive nondiabetic subjects. Insulin-mediated glucose disposal was approximately 30% lower (P less than .03) with GI (9.2 +/- 1.2 mg.kg-1.min-1, mean +/- SE) than with the nonglycosylated hormone (12.6 +/- 0.7 mg.kg-1.min-1) at comparable plasma insulin concentrations (approximately 90 microU/ml). Binding of GI to a specific receptor on circulating cells (erythrocytes and monocytes) was normal. We conclude that in vitro extensive glycosylation of insulin reduces its biological activity in vivo, as reflected by insulin-mediated glucose disposal, probably at a postreceptor level.

It has been shown that L-dopa or dopamine administration influences glucose metabolism, as well as insulin and glucagon release in man. In the present study, the effect of bromocriptine (CB-154), a long-acting dopamine agonist, on insulin, glucagon and growth hormone secretion in 32 acromegalic patients was investigated. Glucose, insulin and plasma glucagon levels were not modified following administration of bromocriptine or placebo. Moreover, plasma GH levels were decreased by more than 50% in 18 of the 32 acromegalics. Mean GH levels were significantly lower with respect to levels observed following placebo at 60 min to the end of the test (p less than 0.001). Administration of a double dose of CB-154 (5 mg po) one hour before arginine test did not affect insulin or glucagon secretion with respect to levels observed during arginine alone. In addition, there was a fall in GH levels similar to that observed following administration of bromocriptine alone. These findings suggest that bromocriptine in itself does not exert a direct action on insulin and glucagon release. Improvement in glucose tolerance and reduction in insulin secretion observed following prolonged CB-154 treatment in acromegalic patients are probably due to a simultaneous inhibition of GH secretion or to other peripheral effects of bromocriptine.

The recent interest in the relation between translation and ideology led to the following project based on a comparative analysis among the Italian short novel for children Pinocchio and its three translations (English, Russian and Turkish) to highlight how the translation choices are determined by a specific cultural background and ruling power.If external influences cannot be avoided, a translation should respect its main scope of being the source for a cultural change. Therefore, the two questions that have eventually to be answered are how does the critics of translation relate to the ethics of translation and how can the common reader be protected from unconscious manipulation. Reasoning about the translator's position and the importance of critical reading and foreign language classes will serve the purpose.

To evaluate the time course of changes in red cell sorbitol (RCS) concentration in relation to variations of plasma glucose levels, RCS was determined in 7 normal subjects during i.v. glucose infusion (IVGTT); in 6 hyperglycemic insulin-dependent diabetic subjects while glycemia was normalized with Biostator GC 115 and in 4 diabetic patients in previously poor metabolic control, in whom normal glycemia was obtained in 8–10 days by intensive insulin therapy. During IVGTT, plasma glucose levels increased with significant differences from baseline at 5, 10, 16, 25, 60, 100 and 160 min and returned to basal levels after 3h; RCS concentration showed small and insignificant increases. During i.v. insulin infusion, plasma glucose fell to almost normal levels within roughly 3h; RCS levels showed a gradual reduction becoming significant at 180 min. In the third study, decrease in plasma glucose was always associated with a fall in RCS level which became significant between the 2nd and the 3rd day of the study. Thus, RCS levels were not affected by very short-term variations of glycemia but by a previous hyperglycemic crisis that lasted a few hours. There were therefore medium-term variations of RCS level. In conclusion, RCS determination is not useful as an index of metabolic control in diabetes.

We studied glucagon responses to OGTT and insulin and arginine stimulation in 12 out of 21 patients who were found positive for alpha cell autoantibodies (ACA) during routine screening procedures for autoimmunity in a group of 4080 individuals. The study was repeated in 8 subjects after an average observation period of 42 months. In both studies glucagon plasma levels were normal and independent of ACA titres, ACA ability to fix complement and ACA ability to cross-react with duodenal alpha cells. The clinical significance of ACA remains to be elucidated.

The purpose of this study was to investigate whether the administration of acetoacetic and hydrochloric acids in a group of control and Type 1 (insulin-dependent) diabetic patients influenced renal haemodynamics. Renal plasma flow increased from 657 +/- 88 to 762 +/- 81 ml X min-1. 1.73 m-2 in diabetic patients (p less than 0.01) and from 590 +/- 71 to 691 +/- 135 in control subjects (p less than 0.01). Glomerular filtration rate increased from 135 +/- 9 to 180 +/- 8 ml X min-1. 1.73 m-2 in diabetic patients (p less than 0.001) and from 117 +/- 8 to 145 +/- 7 in control subjects (p less than 0.01). Similar effects on renal haemodynamics, even if less pronounced, were observed with low dose acetoacetic but not with hydrochloric acid infusion. Total protein, beta 2-microglobulin but not albumin excretion rates were increased by acetoacetic acid. We conclude that an acute increase in blood concentration of ketone bodies within the range found in diabetic patients with poor metabolic control increases renal plasma flow and glomerular filtration rate both in control subjects and diabetic patients and causes a tubular proteinuria.

Plasma and red cell sorbitol concentrations, fasting plasma glucose, glycosylated hemoglobin (GHb) were evaluated in 30 diabetic patients and 42 normal subjects. Red cell sorbitol levels were evaluated in hemolysate and non-hemolyzed samples. Mean red cell sorbitol concentrations evaluated after hemolysis were 21.5 +/- 5 nmol/ml in diabetics and 12.2 +/- 4 nmol/ml in controls (p less than 0.001). Mean values of red cell sorbitol determined in non-hemolyzed samples were 13.9 +/- 3 nmol/ml in diabetics and 8.1 +/- 3 nmol/ml in controls (p less than 0.001). Mean plasma sorbitol concentrations were 8.4 +/- 3 nmol/ml in diabetics and 5.2 +/- 1 nmol/ml in controls (p less than 0.001). The within and between run reproducibilities evaluated in plasma, hemolysate and non-hemolyzed red cells gave the lowest values for hemolyzed red cell samples. The studies on stability showed that samples neutralized and stored at -20 degrees C gave reproducible values if assayed within 3 days. A positive correlation was found between red cell hemolysate sorbitol concentrations and fasting plasma levels in both diabetics (r = 0.56; p less than 0.001) and controls (r = 0.62; p less than 0.001). Red cell hemolysate sorbitol concentrations were also positively correlated to GHb in both diabetics (r = 0.64; p less than 0.001) and controls (r = 0.36; p less than 0.05). We believe the most effective sorbitol assay to be that obtained in hemolyzed red cells and that these values related to glycemic levels could be a useful index of metabolic control and an indicator of tissue sorbitol levels in humans.

The effects of varying concentrations of ethanol (1,10, and 30 mM) and its metabolites (1 mM acetate and 1 and 10 mM acetaldehyde) on insulin and glucagon secretion induced by glucose (11.1 mM) and arginine (20 mM) were studied in isolated perfused pancreas of Sprague-Dawley rats Ethanol and its metabolites did not significantly modify basal secretion of the two hormones. Ethanol reduced glucose-induced insulin secretion by means of a dose-related effect. Arginine-induced insulin output did not seem to be influenced to any significant degree. Acetate and acetaldehyde significantly inhibited glucose and arginine-induced insulin secretion. While ethanol (10 and 30 mM) did not modify glucagon output during arginine perfusion, acetate and acetaldehyde markedly enhanced it. The block of insulin secretion and the increased secretion of glucagon could explain the diabetogenic effect of ethanol demonstrated in vivo. The mechanism by which ethanol acts on the pancreatic β- and α-cells is discussed.

To clarify whether type I diabetes is characterized by insulin resistance, insulin-mediated glucose metabolism (M; milligrams per kg/min) was estimated by means of the glucose clamp technique in five insulin-dependent diabetic patients and six normal subjects. Three glucose clamps were carried out under different metabolic conditions. Free insulin plateaux were similar during each clamp in both groups. The first clamp was performed in normal subjects after an overnight fast [blood glucose, 80 +/- 3 mg/dl (mean +/- SEM)] and in diabetic patients 18 h after insulin withdrawal (blood glucose, 366 +/- 47 mg/dl). Diabetic patients had a M value (4.25 +/- 0.74) not different from normals (5.38 +/- 0.63; P = NS). The second clamp was done with the same glycemic values (approximately 125 mg/dl) in both groups. M increased to 8.07 +/- 1.06 (P less than 0.01) in the normal subjects and decreased to 2.87 +/- 0.50 (P = NS) in the diabetic patients. The M value in the diabetic patients was lower than that in the normal subjects (P less than 0.05). The third clamp was performed in three diabetic patients after 1 month of treatment with continuous sc insulin infusion. The mean blood glucose level was 88 +/- 6 mg/dl, and M was 3.23 +/- 0.38, significantly lower than that of the normal subjects in the basal state (P less than 0.05). No differences were found in insulin binding to erythrocytes. The mean plasma clearance rate (milliliters per m2/min) of free insulin was the same in both groups (428 +/- 113 in normal subjects and 354 +/- 83 in diabetic patients). Basal endogenous glucose production was higher in the diabetics (3.13 +/- 0.48 mg/kg X min) than in the normal subjects (1.71 +/- 0.57). During the clamp, however, endogenous glucose production was similarly inhibited (approximately 95%) in both groups. Multiple glucose clamp studies were also performed at three different insulin infusion rates (21, 73, and 760 mU/m2 X min, respectively) to generate an insulin-dose response curve for glucose disposal in six diabetic patients treated with continuous sc insulin infusion for at least 6 months. This allowed investigation of the effect of chronic strict insulin therapy leading to normal glucose and intermediary metabolite levels and identification of the cellular mechanism of insulin resistance. A significant reduction of the maximal glucose disposal rate (10.7 +/- 0.5 mg/kg X min) was found in these diabetic patients compared to that in normal subjects (14.9 +/- 1.0; P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

We studied 125I-insulin binding to erythrocytes from 14 patients with diabetes secondary to chronic pancreatitis or pancreatectomy and compared the results with those found in 10 patients with type I diabetes and 25 normal controls. Patients with pancreatogenic diabetes had higher 125I-insulin binding and enhanced tissue sensitivity to exogenous insulin measured with the glucose clamp technique as compared with patients with type I diabetes. Similar binding data were obtained with monocytes from 3 patients with pancreatogenic diabetes. The increase in insulin binding seemed due mainly to an increase in receptor number. The increase in insulin binding to cells from patients with pancreatogenic diabetes in comparison with cells from normal subjects was also seen in young-erythrocyte-rich fractions and in old-erythrocyte-rich fractions obtained from the mixed population of circulating erythrocytes by centrifugation in density gradient of Percoll-Pielografin. These data, in the absence of any sign of major hematological disorders, suggest that the increase in insulin receptors seen in erythrocytes and in monocytes from patients with pancreatogenic diabetes, can mirror a general phenomenon on tissues throughout the body, including major target cells for insulin and correlate with the heightened sensitivity to insulin characteristic of these patients. In conclusion, patients with pancreatogenic diabetes have increased insulin binding as compared to controls and to patients with type I diabetes with chronic hypoinsulinemia of the same degree. Thus, in addition to insulin deficiency, other factor (s), such as glucagon deficiency, are responsible for the clinical and metabolic differences between these two conditions of insulin deficiency.

It is well established that cortisol excess causes insulin resistance in man, but the mechanisms responsible for this insulin resistance are poorly understood. We studied five women with Cushing's syndrome with impaired oral glucose tolerance tests and seven normal subjects, plotting the shape of the insulin-induced disposal dose-response curve obtained by means of the euglycemic clamp procedure during four different plasma insulin plateaus at four infusion rates of 21, 73, 760, and 1200 mU/M2 . min. Glucose disposal (M = mg/M2 . min) was calculated as glucose amount infused to maintain euglycemia. In Cushing's syndrome the dose-response curve was shifted to the right in comparison with normal subjects, with a significantly lower M (337 +/- 35 vs. 657 +/- 76 P less than 0.01) during the highest insulin infusion rate [maximal glucose disposal (MGD)] without any significant difference in the levels of insulin half-maximally effective in the stimulation of glucose utilization. Neither erythrocyte nor monocyte maximum insulin receptor binding were different between the two populations. Four Cushing's syndrome patients were studied again after surgical treatment. A marked improvement of MGD was observed without any significant change in insulin-binding capacity. These results, particularly the marked decrease in MGD, a typical feature of postreceptor defects, indicate that cortisol-induced insulin resistance in man is due to an impairment of peripheral insulin action located beyond the hormone-receptor binding step.

Human kidney responds to a meat meal with an increase in glomerular filtration rate (GFR), but the mechanisms regulating kidney hemodynamics following protein intake are poorly understood in Type I insulin-dependent diabetes. In the present study we investigated GFR response to protein intake (600 gr/1.73 m2 meat meal) in nine normal subjects and 21 Type I insulin-dependent diabetic patients with normal albumin excretion rates as well as proximal tubular sodium reabsorption rates and distal sodium delivery (PRNa and DDNa). The same study was reperformed in normal subjects and diabetic patients, with less than a 5 year diabetes duration, following one week of indomethacin treatment. Normal subjects showed a 38% increase in GFR following protein intake, whereas diabetic patients showed a significantly lower response (18%, p less than 0.01). The response of GFR to protein challenge was negatively related to diabetes duration but not to baseline glomerular filtration rate. Indomethacin treatment completely prevented the protein induced GFR increase in normal subjects but not in diabetic patients. Sodium reabsorption rate was increased following protein challenge both at the proximal and distal tubular level, as was net natriuresis.(ABSTRACT TRUNCATED AT 250 WORDS)

[125I]Insulin binding to insulin receptors on circulating monocytes was studied in 9 patients with acromegaly associated with fasting hyperglycemia and was compared to previously reported studies of 11 patients with acromegaly who had normal or nearly normal glucose tolerance and 29 normal volunteers. In the hyperglycemic acromegalic, as had been found in the normoglycemic acromegalic, the total receptor concentration per cell was decreased in proportion to the hyperinsulinemia, i.e. the receptor concentration was inversely related to the basal level of insulin, similar to what is found in patients with obesity, diabetes, and insulin-secreting tumors. However, the acromegalic patients with hyperglycemia failed to show the increase in affinity of the empty receptor that had previously been found in their normoglycemic counterparts. The failure to increase receptor affinity causes the cells of the hyperglycemic acromegalic patients to bind less insulin at each insulin concentration than do the cells of normoglycemic patients. Again, the abnormalities in the patients correlates very closely with abnormalities at the level of the insulin receptor, though the sequence of the molecular events that produce these changes remains to be determined.

The loss of first-phase insulin secretion is a characteristic feature of type 2 diabetic patients. The fast-acting insulin analog lispro provides a therapeutic tool for assessing the metabolic outcome of restoration of an early rise in plasma insulin levels after the ingestion of an oral glucose load. We studied eight type 2 diabetic patients on two different occasions when they received an oral glucose load (50 g) preceded by either human regular insulin or insulin analog lispro (both 0.075 U/kg lean body mass). Tritiated glucose was infused throughout the studies, and the oral glucose was labeled with [13C6]glucose for monitoring systemic and oral glucose kinetics, respectively. Basal plasma glucose (8.2 +/- 0.9 vs. 7.5 +/- 0.8 mmol/l), insulin (224 +/- 21 vs. 203 +/- 21 pmol/l), and endogenous glucose production (10.4 +/- 1.0 vs. 11.1 +/- 1.1 micromol x kg(-1) x min(-1)) were similar on both occasions. In spite of comparable incremental areas under the curve, the time course of plasma insulin concentration was much different. After injection of regular insulin, plasma insulin peaked at 120 min (368 +/- 42 pmol/l), while with lispro, the peak occurred at 60 min (481 +/- 42 pmol/l). Plasma insulin concentration during the last 3 h of the study, however, was lower with lispro compared with regular insulin. The incremental area under the curve of plasma C-peptide was lower with lispro (0.05 +/- 0.01 vs. 0.13 +/- 0.04 micromol/300 min; P < 0.01). After the ingestion of the oral glucose load, plasma glucose concentration increased by 78% at 80-100 min with regular insulin and by 62% with lispro (P < 0.05) and remained lower for the ensuing 3 h. The incremental area under the curve was 46% lower with lispro (715 +/- 109 vs. 389 +/- 109 pmol/300 min; P < 0.01). There was no difference in the two studies in the rate of appearance of the ingested glucose and in the overall rate of glucose disposal. During the initial 90 min, however, the rate of endogenous glucose production was suppressed in a prompter and more profound manner when lispro was administered (1.39 +/- 0.10 vs. 5.00 +/- 1.22 micromol x kg(-1) x min(-1); P < 0.05), while there was no difference in the late prandial phase. These results show that an early rise in plasma insulin levels after the ingestion of a glucose load is associated with a significant improvement in glucose tolerance due to a prompter, though short-lived, suppression of endogenous glucose production. This amelioration in plasma glucose profile prevents late hyperglycemia and hyperinsulinemia. Therefore, restoration of a more physiologic profile of prandial plasma insulin profile represents a rational approach for treatment of type 2 diabetic patients.

Diabetes mellitus is associated with important changes in renal hemodynamics. The purpose of this study was to determine whether an increase in blood concentration patterns of ketone bodies and lactic acid, organic acids often elevated in poorly controlled insulin-dependent diabetes mellitus (IDDM), could contribute to increase glomerular filtration rate (GFR) and renal plasma flow (RPF) regardless of changes in circulating levels of glucose and insulin. Six IDDM patients and six normal subjects were given a saline infusion (15 μmol · min−1 · kg−1) for 2 h, an acetoacetic acid infusion (15 μmol · min−1 · kg−1) for another 2 h, and then a saline infusion after an overnight fast during euglycemic insulin-glucose clamp. Acetoacetic acid infusion resulted in an increase of blood ketone bodies in the range of 0.7–1.5 mM from a basal value of 0.1–0.3 mM. GFR was 125 ± 16 and 136 ± 17 ml · min−1 · 1.73 m−2 in normal and IDDM subjects, respectively, during baseline saline infusion and 138 ± 21 (P < .01 vs. basal level) and 158 ± 15 ml · min−1 · 1.73 m−2 (P < .001 vs. basal level) during acetoacetic acid infusion. During the last saline infusion, renal hemodynamic patterns decreased again to baseline levels. Another six IDDM patients and six normal subjects were given saline, lactic acid, and saline infusions at the same rates of infusion after an overnight fast during euglycemic insulin-glucose clamp. Lactic acid concentration increased from ∼0.5–0.8 to 1.0–1.5 mM in both groups. GFR was 125 ± 9 and 144 ± 18 ml · min−1 · 1.73 m−2 in normal and IDDM subjects, respectively, during baseline saline infusion and 135 ± 8 and 158 ± 16 ml · min1 · 1.73 m−2 during lactic acid infusion (P < .01 vs. basal level). Acetoacetic acid and lactic acid infusion resulted in a 14.7 and 7.6% increase, respectively, in RPF compared with baseline values in normal subjects and in a 12.6 and 6.9% increase, respectively in IDDM subjects. With the same protocol of the previous organic acid infusion, another five normal and six IDDM patients were given an acetic acid infusion (15 μmol · kg−1 · min−1), resulting in an increase of plasma circulating levels of acetic acid from 0.1–0.2 to 0.3–0.4 mM, which was associated with negligible changes in ketone body and lactic acid concentrations. Neither GFR nor RPF were influenced by acetic acid administration. During acetoacetic acid and lactic acid infusion, both lactic and ketone body acid tubular reabsorption rates were three to five times higher than during saline infusion. In conclusion, lactic acid and acetoacetic acid infusion resulting in circulating patterns of these intermediate metabolites comparable with those often found in poorly controlled IDDM subjects induced a significant increase in GFR and RPF in normal and IDDM subjects. The increased GFR was associated with stimulation of organic acid tubular reabsorption rate and was not related to sodium and liquid overload, because it returned to basal value when saline alone was administered again.

It has been suggested that the hemodynamic derangements present in diabetic ketoacidosis are the results not only of profound volume depletion but also of the effects of increased production of vasodilating prostaglandins (PGs), principally PGI2, released by adipose tissue. In animal and in vitro models, prostaglandin synthesis is increased during insulin deficiency. We assessed the effects of short-term ketosis on the metabolic and hemodynamic variables of 10 IDDM patients free from long-term complications and of 9 normal control subjects after a 7-day randomized double-blind indomethacin (INDO) (50 mg q.i.d.) or placebo treatment period. Calf blood flow (CBF), postocclusive reactive hyperemia (PORH), and recovery half-time (an index of overall perfusion) after PORH were measured by plethysmography. Left ventricular and myocardial functions were also studied in each different condition during placebo and INDO treatment in IDDM patients. During placebo treatment, the increase in CBF during ketosis was higher (1.75 ± 0.29 ml · min−1 · 100 ml muscle−1) than during INDO (0.85 ± 0.17 ml · min−1 · 100 ml muscle−1; P = 0.007). PORH was similar in baseline conditions, during ketosis, and in recovery in both the placebo and INDO arms. Recovery half-time significantly increased during placebo (10 ± 2; 200%; P < 0.01) but not during INDO (1 ± 1; 106%; NS) treatment. In normal control subjects, insulin deficiency did not induce any significant effect on hemodynamic variables. In IDDM patients, during placebo treatment, ketosis increased both the cardiac index (from 3.4 ± 0.7 to 4.1 ± 0.8 1 · min−1 · m−2; P < 0.01) and the stroke index (from 42 ± 8 to 49 ± 7 ml/m2; P < 0.01) without changes in left ventricular ejection fraction but with a significant increase in both left and right ventricular end-diastolic volumes. Metabolic recovery induced a normalization of these parameters. INDO treatment significantly blunted these alterations. In summary, we showed that during acute insulin deficiency, INDO-sensitive mechanisms mediate vascular disturbances. Moreover, INDO treatment was capable of completely preventing the cardiac venous return and the left ventricular alterations. INDO does not interfere with the overall ketogenetic process or with insulin-induced metabolic recovery.