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Aims and Hypothesis: The insulin secretion/insulin resistance (IR) (disposition) index (ΔI/ΔG ÷ IR, where Δ is change from baseline, I is insulin, and G is glucose) is commonly used as a measure of β-cell function. This relationship is curvilinear and becomes linear when log transformed. ΔI is determined by 2 variables: insulin secretion rate (ISR) and metabolic clearance of insulin. We postulated that the characteristic curvilinear relationship would be lost if Δ plasma C-peptide (ΔCP) (instead of Δ plasma insulin) was plotted against insulin sensitivity., Methods: A total of 441 individuals with impaired glucose tolerance (IGT) from ACT NOW received an oral glucose tolerance test and were randomized to pioglitazone or placebo for 2.4 years., Results: Pioglitazone reduced IGT conversion to diabetes by 72% (P < .0001). ΔI/ΔG vs the Matsuda index of insulin sensitivity showed the characteristic curvilinear relationship. However, when ΔCP/ΔG or ΔISR/ΔG was plotted against the Matsuda index, the curvilinear relationship was completely lost. This discordance was explained by 2 distinct physiologic effects that altered plasma insulin response in opposite directions: 1) increased ISR and 2) augmented metabolic clearance of insulin. The net result was a decline in the plasma insulin response to hyperglycemia during the oral glucose tolerance test. These findings demonstrate a physiologic control mechanism wherein the increase in ISR ensures adequate insulin delivery into the portal circulation to suppress hepatic glucose production while delivering a reduced but sufficient amount of insulin to peripheral tissues to maintain the pioglitazone-mediated improvement in insulin sensitivity without excessive hyperinsulinemia., Conclusions: These results demonstrate the validity of the disposition index when relating the plasma insulin response to insulin sensitivity but underscore the pitfall of this index when drawing conclusions about β-cell function, because insulin secretion declined despite an increase in the plasma insulin response.

Aim: The aim of this study was to examine the relationship between whole-body insulin-mediated glucose disposal and the fasting plasma glucose concentration in nondiabetic individuals., Research Design and Methods: Two hundred fifty-three nondiabetic subjects with normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance, and combined glucose intolerance received a 75-g oral glucose tolerance test and euglycemic hyperinsulinemic clamp. Total glucose disposal (TGD) during the insulin clamp was compared in IFG and NGT individuals and was related to fasting and 2-hour plasma glucose concentrations in each group., Results: TGD varied considerably between NGT and IFG individuals and displayed a strong inverse relationship with the 2-hour plasma glucose (PG; r = 0.40, P < .0001) but not with the fasting PG. When IFG and NGT individuals were stratified based on their 2-hour PG concentration, the increase in 2-hour PG was associated with a progressive decrease in TGD in both groups, and the TGD was comparable among NGT and IFG individuals., Conclusion: The present results indicate the following: 1) as in NGT, insulin-stimulated TGD varies considerably in IFG individuals; 2) the large variability in TGD in IFG and NGT individuals is related to the 2-hour PG concentration; and 3) after adjustment for the 2-hour proglucagon concentration, IFG subjects have comparable TGD with NGT individuals.

Insulin resistance and dysregulation of free fatty acid (FFA) metabolism are core defects in type 2 diabetic (T2DM) and obese normal glucose tolerant (NGT) individuals. Impaired muscle mitochondrial function (reduced ATP synthesis) also has been described in insulin-resistant T2DM and obese subjects. We examined whether reduction in plasma FFA concentration with acipimox improved ATP synthesis rate and altered reactive oxygen species (ROS) production. Eleven NGT obese and 11 T2DM subjects received 1) OGTT, 2) euglycemic insulin clamp with muscle biopsy, and 3) (1)H-magnetic resonance spectroscopy of tibialis anterior muscle before and after acipimox (250 mg every 6 h for 12 days). ATP synthesis rate and ROS generation were measured in mitochondria isolated from muscle tissue ex vivo with chemoluminescence and fluorescence techniques, respectively. Acipimox 1) markedly reduced the fasting plasma FFA concentration and enhanced suppression of plasma FFA during oral glucose tolerance tests and insulin clamp in obese NGT and T2DM subjects and 2) enhanced insulin-mediated muscle glucose disposal and suppression of hepatic glucose production. The improvement in insulin sensitivity was closely correlated with the decrease in plasma FFA in obese NGT (r = 0.81) and T2DM (r = 0.76) subjects (both P < 0.001). Mitochondrial ATP synthesis rate increased by >50% in both obese NGT and T2DM subjects and was strongly correlated with the decrease in plasma FFA and increase in insulin-mediated glucose disposal (both r > 0.70, P < 0.001). Production of ROS did not change after acipimox. Reduction in plasma FFA in obese NGT and T2DM individuals improves mitochondrial ATP synthesis rate, indicating that the mitochondrial defect in insulin-resistant individuals is, at least in part, reversible., (© 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.)

In Brief Impaired insulin secretion, increased hepatic glucose production, and decreased peripheral glucose utilization are the core defects responsible for the development and progression of type 2 diabetes. However, the pathophysiology of this disease also includes adipocyte insulin resistance (increased lipolysis), reduced incretin secretion/sensitivity, increased glucagon secretion, enhanced renal glucose reabsorption, and brain insulin resistance/neurotransmitter dysfunction. Although current diabetes management focuses on lowering blood glucose, the goal of therapy should be to delay disease progression and eventual treatment failure. Recent innovative treatment approaches target the multiple pathophysiological defects present in type 2 diabetes. Optimal management should include early initiation of combination therapy using multiple drugs with different mechanisms of action. This review examines novel therapeutic options that hold particular promise.

Objective: To assess the relation between fetal and maternal blood type (ABO, Rh) incompatibility and development of gestational diabetes mellitus (GDM)., Materials and Methods: A total of 500 pregnant women underwent diagnostic test for GDM by a 100-g oral glucose tolerance test (OGTT) after an 8 to 12-h overnight fast participated in this study. OGTT was performed between the 24-28 weeks of gestation, but participants who were at high risk for GDM were tested after the first prenatal visit. In the postpartum period, maternal and infant blood types were determined. Presence of GDM was evaluated in terms of matched and unmatched fetal and maternal ABO and Rh blood types separately., Results: GDM was detected in 235 participants. Unmatched ABO blood types between the mother-infant pairs were present in 44.7% (n=105) of GDM (+) and 35.8 % (n=95) of GDM (-) patients. Incompatible feto-maternal ABO blood type was positively correlated with development of GDM which was marginally significant. (p=0.045; R=1.2;95% CL; 1.004-1.48). However, Rh feto-maternal blood type incompatibility was not related with development of GDM., Conclusions: Feto-maternal ABO blood type incompatibility may be a weak risk factor for the development of GDM.

Obesity is a major public health concern, and complementary research strategies have been directed toward the identification of the underlying causative gene mutations that affect the normal pathways and networks that regulate energy balance. Here, we describe an autosomal-recessive morbid-obesity syndrome and identify the disease-causing gene defect. The average body mass index of affected family members was 48.7 (range = 36.7-61.0), and all had features of the metabolic syndrome. Homozygosity mapping localized the disease locus to a region in 3q29; we designated this region the morbid obesity 1 (MO1) locus. Sequence analysis identified a homozygous nonsense mutation in CEP19, the gene encoding the ciliary protein CEP19, in all affected family members. CEP19 is highly conserved in vertebrates and invertebrates, is expressed in multiple tissues, and localizes to the centrosome and primary cilia. Homozygous Cep19-knockout mice were morbidly obese, hyperphagic, glucose intolerant, and insulin resistant. Thus, loss of the ciliary protein CEP19 in humans and mice causes morbid obesity and defines a target for investigating the molecular pathogenesis of this disease and potential treatments for obesity and malnutrition., (Copyright © 2013 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Cardiomyocyte hypertrophy is the cellular response that mediates pathologic enlargement of the heart. This maladaptation is also characterized by cell behaviors that are typically associated with apoptosis, including cytoskeletal reorganization and disassembly, altered nuclear morphology, and enhanced protein synthesis/translation. Here, we investigated the requirement of apoptotic caspase pathways in mediating cardiomyocyte hypertrophy. Cardiomyocytes treated with hypertrophy agonists displayed rapid and transient activation of the intrinsic-mediated cell death pathway, characterized by elevated levels of caspase 9, followed by caspase 3 protease activity. Disruption of the intrinsic cell death pathway at multiple junctures led to a significant inhibition of cardiomyocyte hypertrophy during agonist stimulation, with a corresponding reduction in the expression of known hypertrophic markers (atrial natriuretic peptide) and transcription factor activity [myocyte enhancer factor-2, nuclear factor kappa B (NF-κB)]. Similarly, in vivo attenuation of caspase activity via adenoviral expression of the biologic effector caspase inhibitor p35 blunted cardiomyocyte hypertrophy in response to agonist stimulation. Treatment of cardiomyocytes with procaspase 3 activating compound 1, a small-molecule activator of caspase 3, resulted in a robust induction of the hypertrophy response in the absence of any agonist stimulation. These results suggest that caspase-dependent signaling is necessary and sufficient to promote cardiomyocyte hypertrophy. These results also confirm that cell death signal pathways behave as active remodeling agents in cardiomyocytes, independent of inducing an apoptosis response.

Objective: To evaluate the effects of two bariatric procedures versus intensive medical therapy (IMT) on β-cell function and body composition., Research Design and Methods: This was a prospective, randomized, controlled trial of 60 subjects with uncontrolled type 2 diabetes (HbA1c 9.7 ± 1%) and moderate obesity (BMI 36 ± 2 kg/m(2)) randomized to IMT alone, IMT plus Roux-en-Y gastric bypass, or IMT plus sleeve gastrectomy. Assessment of β-cell function (mixed-meal tolerance testing) and body composition was performed at baseline and 12 and 24 months., Results: Glycemic control improved in all three groups at 24 months (N = 54), with a mean HbA1c of 6.7 ± 1.2% for gastric bypass, 7.1 ± 0.8% for sleeve gastrectomy, and 8.4 ± 2.3% for IMT (P < 0.05 for each surgical group versus IMT). Reduction in body fat was similar for both surgery groups, with greater absolute reduction in truncal fat in gastric bypass versus sleeve gastrectomy (-16 vs. -10%; P = 0.04). Insulin sensitivity increased significantly from baseline in gastric bypass (2.7-fold; P = 0.004) and did not change in sleeve gastrectomy or IMT. β-Cell function (oral disposition index) increased 5.8-fold in gastric bypass from baseline, was markedly greater than IMT (P = 0.001), and was not different between sleeve gastrectomy versus IMT (P = 0.30). At 24 months, β-cell function inversely correlated with truncal fat and prandial free fatty acid levels., Conclusions: Bariatric surgery provides durable glycemic control compared with intensive medical therapy at 2 years. Despite similar weight loss as sleeve gastrectomy, gastric bypass uniquely restores pancreatic β-cell function and reduces truncal fat, thus reversing the core defects in diabetes.

Aim: The aim was to compare body mass index (BMI), waist circumference (WC), waist hip ratio (WHR), and waist height ratio (WHtR) to identify the best predictor of metabolic syndrome (MetS) among Qatari adult population., Methods: A cross-sectional survey from April 2011 to December 2012. Data was collected from 1552 participants followed by blood sampling. MetS was defined according to Third Adult Treatment Panel (ATPIII) and International Diabetes Federation (IDF). Receiver operating characteristics (ROC) curve analysis was performed., Results: Among men, WC followed by WHR and WHtR yielded the highest area under the curve (AUC) (0.78; 95% CI 0.74-0.82 and 0.75; 95% CI 0.71-0.79, resp.). Among women, WC followed by WHtR yielded the highest AUC (0.81; 95% CI 0.78-0.85 & 0.79; 95% CI 0.76-0.83, resp.). Among men, WC at a cut-off 99.5 cm resulted in the highest Youden index with sensitivity 81.6% and 63.9% specificity. Among women, WC at a cut-off 91 cm resulted in the highest Youden index with the corresponding sensitivity and specificity of 86.5% and 64.7%, respectively. BMI had the lowest sensitivity and specificity in both genders., Conclusion: WC at cut-off 99.5 cm in men and 91 cm in women was the best predictor of MetS in Qatar.

Objective: To determine the effectiveness of targeted pharmacologic interventions to reverse documented pathophysiologic abnormalities in prediabetes., Methods: Patients with impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) were treated with insulin sensitizers (pioglitazone + metformin) or insulin sensitizers + exenatide on the basis of oral glucose tolerance testing-derived indices of insulin resistance and impaired β-cell function. Patients who declined pharmacologic therapy received lifestyle modification only., Results: One hundred five patients with IGT and/or IFG were treated with insulin sensitizers (pioglitazone + metformin) (n = 40), insulin sensitizers + exenatide (n = 47), or lifestyle modification only (n = 18). After a mean follow-up period of 8.9 months, the lifestyle modification group demonstrated no significant changes in fasting plasma glucose, plasma glucose area under the curve during oral glucose tolerance testing, insulin sensitivity, or β-cell function. In the pioglitazone + metformin group (24 hours off medication), fasting plasma glucose fell from 109 to 102 mg/dL; plasma glucose area under the curve decreased by 12.0%; insulin sensitivity and β-cell function improved by 42% and 50%, respectively (all P<.001); 14.3% converted to normal glucose tolerance; and no patient developed diabetes. In the pioglitazone + metformin + exenatide group (24 hours off medication), fasting plasma glucose fell from 109 to 98 mg/dL; plasma glucose area under the curve decreased by 21.2%; insulin sensitivity and β-cell function improved by 52% and 109%, respectively (all P<.001); 59.1% of patients with IGT reverted to normal glucose tolerance; and no patient developed diabetes., Conclusions: Targeted pathophysiologic therapy based on oral glucose tolerance test-derived measures of insulin sensitivity and β-cell function can be implemented in general internal medicine and endocrine practice and is associated with marked improvement in glucose tolerance and reversion of prediabetes to normal glucose tolerance in more than 50% of patients.

Individuals with impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) are at high risk, not only to develop diabetes mellitus, but also to experience an adverse cardiovascular (CV) event (myocardial infarction, stroke, CV death) later in life. The underlying pathophysiologic disturbances (insulin resistance and impaired β-cell function) responsible for the development of type 2 diabetes are maximally/near maximally expressed in subjects with IGT/IFG. These individuals with so-called prediabetes manifest all of the same CV risk factors (dysglycemia, dyslipidemia, hypertension, obesity, physical inactivity, insulin resistance, procoagulant state, endothelial dysfunction, inflammation) that place patients with type 2 diabetes at high risk for macrovascular complications. The treatment of these CV risk factors should follow the same guidelines established for patients with type 2 diabetes, and should be aggressively followed to reduce future CV events., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: Aging increases the risk of developing impaired glucose tolerance (IGT) and type 2 diabetes. It has been proposed that increased reactive oxygen species (ROS) generation by dysfunctional mitochondria could play a role in the pathogenesis of these metabolic abnormalities. We examined whether aging per se (in subjects with normal glucose tolerance [NGT]) impairs mitochondrial function and how this relates to ROS generation, whether older subjects with IGT have a further worsening of mitochondrial function (lower ATP production and elevated ROS generation), and whether exercise reverses age-related changes in mitochondrial function., Research Design and Methods: Mitochondrial ATP and ROS production were measured in muscle from younger individuals with NGT, older individuals with NGT, and older individuals with IGT. Measurements were performed before and after 16 weeks of aerobic exercise., Results: ATP synthesis was lower in older subjects with NGT and older subjects with IGT versus younger subjects. Notably, mitochondria from older subjects (with NGT and IGT) displayed reduced ROS production versus the younger group. ATP and ROS production were similar between older groups. Exercise increased ATP synthesis in the three groups. Mitochondrial ROS production also increased after training. Proteomic analysis revealed downregulation of several electron transport chain proteins with aging, and this was reversed by exercise., Conclusions: Old mitochondria from subjects with NGT and IGT display mitochondrial dysfunction as manifested by reduced ATP production but not with respect to increased ROS production. When adjusted to age, the development of IGT in elderly individuals does not involve changes in mitochondrial ATP and ROS production. Lastly, exercise reverses the mitochondrial phenotype (proteome and function) of old mitochondria.

In the U.S., ∼ 21 × 10(6) individuals have type 2 diabetes, and twice as many have impaired glucose tolerance (IGT). Approximately 40-50% of individuals with IGT will progress to type 2 diabetes over their lifetime. Therefore, treatment of high-risk individuals with IGT to prevent type 2 diabetes has important medical, economic, social, and human implications. Weight loss, although effective in reducing the conversion of IGT to type 2 diabetes, is difficult to achieve and maintain. Moreover, 40-50% of IGT subjects progress to type 2 diabetes despite successful weight reduction. In contrast, pharmacological treatment of IGT with oral antidiabetic agents that improve insulin sensitivity and preserve β-cell function--the characteristic pathophysiological abnormalities present in IGT and type 2 diabetes--uniformly have been shown to prevent progression of IGT to type 2 diabetes. The most consistent results have been observed with the thiazolidinediones (Troglitazone in the Prevention of Diabetes [TRIPOD], Pioglitazone in the Prevention of Diabetes [PIPOD], Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication [DREAM], and Actos Now for the Prevention of Diabetes [ACT NOW]), with a 50-70% reduction in IGT conversion to diabetes. Metformin in the U.S. Diabetes Prevention Program (DPP) reduced the development of type 2 diabetes by 31% and has been recommended by the American Diabetes Association (ADA) for treating high-risk individuals with IGT. The glucagon-like peptide-1 analogs, which augment insulin secretion, preserve β-cell function, and promote weight loss, also would be expected to be efficacious in preventing the progression of IGT to type 2 diabetes. Because individuals in the upper tertile of IGT are maximally/near-maximally insulin resistant, have lost 70-80% of their β-cell function, and have an ∼ 10% incidence of diabetic retinopathy, pharmacological intervention, in combination with diet plus exercise, should be instituted.

Specification and early patterning of the vertebrate heart are dependent on both canonical and noncanonical wingless (Wnt) signal pathways. However, the impact of each Wnt pathway on the later stages of myocardial development and differentiation remains controversial. Here, we report that the components of each Wnt signal conduit are expressed in the developing and postnatal heart, yet canonical/β-catenin activity is restricted to nonmyocardial regions. Subsequently, we observed that noncanonical Wnt (Wnt11) enhanced myocyte differentiation while preventing stabilization of the β-catenin protein, suggesting active repression of canonical Wnt signals. Wnt11 stimulation was synonymous with activation of a caspase 3 signal cascade, while inhibition of caspase activity led to accumulation of β-catenin and a dramatic reduction in myocyte differentiation. Taken together, these results suggest that noncanonical Wnt signals promote myocyte maturation through caspase-mediated inhibition of β-catenin activity.

Activation of caspase-3 is generally acknowledged as a penultimate step in apoptotic cell death pathways. Two studies in this issue of Cell Stem Cell (Fujita et al., 2008; Janzen et al., 2008) provide compelling data to demonstrate that caspase-3 is also a conserved inductive cue for stem cell differentiation.

This study was undertaken to test the hypothesis that short-term exposure (4 h) to physiological hyperinsulinemia in normal, healthy subjects without a family history of diabetes would induce a low grade inflammatory response independently of glycemic status. Twelve normal glucose tolerant subjects received a 4-h euglycemic hyperinsulinemic clamp with biopsies of the vastus lateralis muscle. Microarray analysis identified 121 probe sets that were significantly altered in response to physiological hyperinsulinemia while maintaining euglycemia. In normal, healthy human subjects insulin increased the mRNAs of a number of inflammatory genes (CCL2, CXCL2 and THBD) and transcription factors (ATF3, BHLHB2, HES1, KLF10, JUNB, FOS, and FOSB). A number of other genes were upregulated in response to insulin, including RRAD, MT, and SGK. CITED2, a known coactivator of PPARalpha, was significantly downregulated. SGK and CITED2 are located at chromosome 6q23, where we previously detected strong linkage to fasting plasma insulin concentrations. We independently validated the mRNA expression changes in an additional five subjects and closely paralleled the results observed in the original 12 subjects. A saline infusion in healthy, normal glucose-tolerant subjects without family history of diabetes demonstrated that the genes altered during the euglycemic hyperinsulinemic clamp were due to hyperinsulinemia and were unrelated to the biopsy procedure per se. The results of the present study demonstrate that insulin acutely regulates the levels of mRNAs involved in inflammation and transcription and identifies several candidate genes, including HES1 and BHLHB2, for further investigation.

Objective: To assess the contribution of decreased glucose clearance to the rise in fasting plasma glucose (FPG) in the nondiabetic range., Research Design and Methods: A total of 120 subjects with normal glucose tolerance received an oral glucose tolerance test and euglycemic insulin clamp with 3-[(3)H]glucose. The basal and insulin-stimulated rates of glucose appearance, glucose disappearance, and glucose clearance and the basal hepatic insulin resistance index were calculated. Simple Pearson's correlation was used to assess the relationship between variables., Results: The increase in FPG (range 75-125 mg/dl) correlated (r = 0.32, P < 0.0001) with the increase in BMI (20-50 kg/m(2)). The fasting plasma insulin (FPI) concentration also increased progressively with the increase in BMI (r = 0.62, P < 0.0001). However, despite increasing FPI, the basal glucose clearance rate declined and correlated with the increase in BMI (r = -0.56, P < 0.0001). Basal hepatic glucose production (HGP) decreased with increasing BMI (r = -0.51, P < 0.0001) and correlated inversely with the increase in FPI (r = -0.32, P < 0.0001). The hepatic insulin resistance (basal HGP x FPI) increased with rising BMI (r = 0.52, P < 0.0001). During the insulin clamp, glucose disposal declined with increasing BMI (r = -0.64, P < 0.0001) and correlated with the basal glucose clearance (r = 0.39, P < 0.0001)., Conclusions: These results demonstrate that in nondiabetic subjects, rising FPG is associated with a decrease (not an increase) in basal hepatic glucose production and is explained by a reduction in glucose clearance.

Objective: To estimate the predictive value of exhaled breath condensate (EBC) hydrogen peroxide (H2O2) concentration and pH as non-invasive markers in asthma., Methods: Fifty patients with unstable, steroid naive atopic asthma were included in the study, 25 with intermittent asthma and 25 with persistent asthma. Asthma diagnosis was according to the National Heart Lung and Blood Institute guidelines for the diagnosis and management of asthma. Forced expiratory volume in one second (FEV1) was measured by computerized spirometry. The EBC H2O2 assay was carried out using the colorimetric assay. The study was conducted from January to December 2005 in the Asthma and Allergy Center, Tikrit, Iraq., Results: The EBC H2O2 concentration was higher in the asthmatic group (0.91 micromol) as compared with the control (0.23 micromol). There was an inverse correlation between EBC H2O2 concentration and FEV1 predicted percent for asthmatic patients. The mean EBC pH was lower in the asthmatic than the control group. There was a positive correlation between EBC pH and FEV1 predicted percent for asthmatic patients. There was an inverse correlation between EBC H2O2 concentration and pH for all asthmatic patients, intermittent, and persistent asthmatic groups., Conclusion: Exhaled breath condensate hydrogen peroxide concentration and pH was a good non-invasive marker for asthma, whether it was with a persistent or intermittent course.

Aim: Our aim was to assess the effect of chronic hyperglycemia on glucose- and insulin-mediated suppression of glucagon secretion by the alpha-cell., Methods: Thirty subjects with normal glucose tolerance, 27 with impaired fasting glucose and/or impaired glucose tolerance, and 32 type 2 diabetic subjects were studied with oral glucose tolerance test (OGTT) and euglycemic hyperinsulinemic clamp. Fasting plasma glucagon concentration and plasma glucagon concentration during the OGTT and insulin clamp were measured., Results: During the OGTT, the decrement in the plasma glucagon concentration (area under the curve) was correlated inversely with the fasting plasma glucose concentration (r = -0.35; P < 0.001). As the fasting glucose level increased, the suppression of plasma glucagon progressively diminished. In contrast, during the euglycemic insulin clamp, the suppression of plasma glucagon was not correlated with the fasting plasma glucose concentration and was similar in subjects with normal glucose tolerance, subjects with impaired fasting glucose/impaired glucose tolerance, and diabetic subjects: 18, 23, and 18%, respectively., Conclusion: Insulin-mediated suppression of glucagon secretion is unrelated to the fasting plasma glucose concentration and is not impaired by chronic hyperglycemia. Thus, the defect in plasma glucagon suppression during the OGTT most likely results from impaired glucose-mediated glucagon suppression. The close correlation between fasting plasma glucose concentration and reduced glucagon suppression suggests a glucotoxic effect on alpha-cell function.

Background: Microvascular complications of diabetes contribute significantly to the disease morbidity. The metabolic syndrome is common among subjects with diabetes and is a very important risk factor for macrovascular complications. However, its contribution to the microvascular complication has not been assessed., Objectives: To assess the risk of microvascular complications associated with the metabolic syndrome in diabetes subjects., Methods: The study group comprised 415 diabetic subjects attending a primary care clinic. The prevalence of microvascular complications was compared between 270 diabetic subjects with metabolic syndrome (NCEP-III criteria) and 145 diabetic patients without., Results: We found that as a group, diabetic subjects with metabolic syndrome had a significantly higher frequency of microvascular-related complications than diabetic subjects without the syndrome (46.6% and 26.8% respectively, P= 0.0005). These include microalbuminuria (41.5% vs. 23.9%, P= 0.013), neuropathy (10.4% vs. 7.5%, P = 0.38), retinopathy (9.6% vs. 4.1%, P = 0.046) and leg ulcers (7.9% vs. 2.8%, P = 0.044). After adjustment for age, gender, glycemic control, disease duration, lipid profile and blood pressure, metabolic syndrome was associated with a significantly higher risk of microvascular complications: odds ratio (95% confidence interval) for nephropathy 2.27 (1.53-3.34), neuropathy 1.77 (0.79-4.0), retinopathy 3.42 (1.2-9.87), and leg ulcers 3.57 (1.08-11.95)., Conclusions: In addition to hyperglycemia and disease duration, the metabolic syndrome is a significant risk factor for the development of microvascular complications in diabetic subjects.

Protein sorting through vesicular compartments is highly regulated to maintain the integrity and signaling of intracellular organelles in eukaryotic cells. Sorting Nexin-2 (SNX2) is involved in protein sorting in the trans-Golgi network, endosome, and/or lysosome compartments, with loss of function leading to defect in protein sorting and stress on organelles. To investigate the function of SNX2, we have identified the DEAD-box helicase Abstrakt (Abs) as an SNX2-interacting protein. The N-terminal domain of Abs interacts with the phox homology (PX) domain of SNX2 suggesting that PX domains may also participate in protein-protein interaction. Interestingly, both proteins undergo nucleocytoplasmic shuttling, and this process is responsive to serum withdrawal for Abs. Finally, expression of Abs reduced the cellular expression of SNX2 without altering its steady state mRNA levels. This unexpected interaction provides a novel mechanism whereby expression of proteins involved in membrane trafficking could be regulated by an RNA helicase., ((c) 2004 Wiley-Liss, Inc.)

Reaction of 2-hydrazinopyridine (1) with D-xylose, D-galactose, D-glucose and D-fructose afforded the corresponding hydrazones mainly in the acyclic forms 2, 3, 6 and 11 with minor amounts of the cyclic structures. Oxidative cyclization of the hydrazones with bromine in methanol resulted in the formation of the 3-(polyhydroxyalkyl)-1,2,4-triazolo[4,3-a]pyridine derivatives 13-15 whose acetylation afforded the acetylated derivatives 16-18. Assignment of 1D and 2D NMR spectral data in addition to 15N NMR experiments led to complete characterization of the products.

The prenylated Rab acceptor (PRA) 1 is a protein that binds prenylated Rab GTPases and inhibits their removal from the membrane by GDI. We describe here the isolation of a second isoform that can also bind Rab GTPases in a guanine nucleotide-independent manner. The two PRA isoforms showed distinct intracellular localization with PRA1 localized primarily to the Golgi complex and PRA2 to the endoplasmic reticulum (ER) compartment. The localization signal was mapped to the COOH-terminal domain of the two proteins. A DXEE motif served to target PRA1 to the Golgi. Mutation of any one of the acidic residues within this motif resulted in significant retention of PRA1 in the ER compartment. Moreover, the introduction of a di-acidic motif to the COOH-terminal domain of PRA2 resulted in partial localization to the Golgi complex. The domain responsible for ER localization of PRA2 was also confined to the carboxyl terminus. Our results showed that these sorting signals were primarily responsible for the differential localization of the two PRA isoforms.

Atrophic gastritis is an autoimmune gastropathy in which there is destruction of gastric parietal cells. This results in intrinsic factor deficiency and disturbance in vitamin B12 absorption. Its clinical manifestationa are therefore the consequences of B12 deficiency and include anemia and neurological defect. In addition, lack of B12 results in metabolic changes, including disturbances of methionine metabolism and accumulation of homocysteine. In recent years, there has been increasing evidence suggesting that hyperhomocysteinemia is a risk factor for thrombo-embolic disease. We describe a 51-year-old man with atrophic gastritis, severe B12 deficiency and hyperhomocysteinemia. The initial clinical manifestation was pulmonary embolism, without either anemia or neurological signs. B12 deficiency should therefore be considered in patients being investigated for hypercoagulability.

Arginine-vasopressin has a widespread distribution in the nervous system, and has been implicated in cellular and behavioral functions. Its effect on the neuromuscular synapse reveals that it produces long-lasting augmentation in synaptic transmission due to an increase in spontaneous and nerve stimulation evoked quantal transmitter release. No significant postsynaptic effect was detected.