Correlation between plasma glutamate and adiponectin in patients with type 2 diabetes.

Visceral fat accumulation is a major determinant of type 2 diabetes mellitus and cardiovascular diseases. Recent studies have reported that glutamate is the most elevated amino acid in the plasma amino acid profile in patients with obesity and/or visceral fat accumulation. Here, we show the relationship between plasma glutamate and the clinical features of patients with type 2 diabetes. The study subjects were 62 (28 men and 34 women) Japanese patients with type 2 diabetes. Blood profiles, including glutamate and adiponectin (APN) levels and estimated visceral fat area (eVFA), were measured. We also evaluated the plasma amino acid levels in mice with or without obesity by GC/MS analysis. In patients with type 2 diabetes, plasma glutamate was positively correlated with BMI, eVFA, and fasting insulin but negatively correlated with APN and duration of diabetes. Additionally, multiple regression analysis revealed that plasma glutamate was a significant determinant of APN. The plasma glutamate level was most significantly increased in obese mice compared to control mice, and it was negatively correlated with APN. These results suggest that the level of plasma glutamate could be a strong indicator of adipocyte dysfunction in patients with type 2 diabetes.

Distinct signaling by insulin and IGF-1 receptors and their extra- and intracellular domains.

Insulin and insulin-like growth factor 1 (IGF-1) receptors share many downstream signaling pathways but have unique biological effects. To define the molecular signals contributing to these distinct activities, we performed global phosphoproteomics on cells expressing either insulin receptor (IR), IGF-1 receptor (IGF1R), or chimeric IR-IGF1R receptors. We show that IR preferentially stimulates phosphorylations associated with mammalian target of rapamycin complex 1 (mTORC1) and Akt pathways, whereas IGF1R preferentially stimulates phosphorylations on proteins associated with the Ras homolog family of guanosine triphosphate hydrolases (Rho GTPases), and cell cycle progression. There were also major differences in the phosphoproteome between cells expressing IR versus IGF1R in the unstimulated state, including phosphorylation of proteins involved in membrane trafficking, chromatin remodeling, and cell cycle. In cells expressing chimeric IR-IGF1R receptors, these differences in signaling could be mapped to contributions of both the extra- and intracellular domains of these receptors. Thus, despite their high homology, IR and IGF1R preferentially regulate distinct networks of phosphorylation in both the basal and stimulated states, allowing for the unique effects of these hormones on organismal function.

Impact of glycosylphosphatidylinositol-specific phospholipase D on hepatic diacylglycerol accumulation, steatosis, and insulin resistance in diet-induced obesity.

Glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) is an enzyme that specifically cleaves GPI anchors. Previous human studies suggested the relationship of GPI-PLD to insulin resistance, type 1 and type 2 diabetes, and nonalcoholic fatty liver disease (NAFLD). However, the biological roles of GPI-PLD have not been elucidated. Here, we hypothesized that GPI-PLD impacted on lipid and glucose metabolism, especially in the liver. GPI-PLD mRNA was most highly expressed in the liver, and the hepatic mRNA level and circulating concentration of GPI-PLD were significantly augmented in diabetic mice. To investigate in vivo functions of GPI-PLD, we generated GPI-PLD knockout (GP-KO) mice. Mice lacking GPI-PLD exhibited the amelioration of glucose intolerance and hepatic steatosis under high-fat and high-sucrose diet. Furthermore, diacylglycerol (DAG) content was significantly decreased, and PKCε activity was suppressed in the livers of GP-KO mice. In vitro knockdown and overexpression experiments of GPI-PLD using rat primary hepatocytes showed the GPI-PLD-dependent regulation of intracellular DAG content. Finally, serum GPI-PLD levels were strongly and independently associated with serum alanine transaminase (R = 0.37, P = 0.0006) and triglyceride (R = 0.34, P = 0.001) levels in male subjects with metabolic syndrome. In conclusion, upregulation of hepatic GPI-PLD in diabetic conditions leads to DAG accumulation in the liver by shedding GPI anchors intracellularly, which may play a causal role in impaired hepatic insulin signaling and the progression of NAFLD.

The unique prodomain of T-cadherin plays a key role in adiponectin binding with the essential extracellular cadherin repeats 1 and 2.

Adiponectin, an adipocyte-derived circulating protein, accumulates in the heart, vascular endothelium, and skeletal muscles through an interaction with T-cadherin (T-cad), a unique glycosylphosphatidylinositol-anchored cadherin. Recent studies have suggested that this interaction is essential for adiponectin-mediated cardiovascular protection. However, the precise protein-protein interaction between adiponectin and T-cad remains poorly characterized. Using ELISA-based and surface plasmon analyses, we report here that T-cad fused with IgG Fc as a fusion tag by replacing its glycosylphosphatidylinositol-anchor specifically bound both hexameric and larger multimeric adiponectin with a dissociation constant of ∼1.0 nm and without any contribution from other cellular or serum factors. The extracellular T-cad repeats 1 and 2 were critical for the observed adiponectin binding, which is required for classical cadherin-mediated cell-to-cell adhesion. Moreover, the 130-kDa prodomain-bearing T-cad, uniquely expressed on the cell surface among members of the cadherin family and predominantly increased by adiponectin, contributed significantly to adiponectin binding. Inhibition of prodomain-processing by a prohormone convertase inhibitor increased 130-kDa T-cad levels and also enhanced adiponectin binding to endothelial cells both by more preferential cell-surface localization and by higher adiponectin-binding affinity of 130-kDa T-cad relative to 100-kDa T-cad. The preferential cell-surface localization of 130-kDa T-cad relative to 100-kDa T-cad was also observed in normal mice aorta in vivo In conclusion, our study shows that a unique key feature of the T-cad prodomain is its involvement in binding of the T-cad repeats 1 and 2 to adiponectin and also demonstrates that adiponectin positively regulates T-cad abundance.

Increased Dynamics of Tricarboxylic Acid Cycle and Glutamate Synthesis in Obese Adipose Tissue: IN VIVO METABOLIC TURNOVER ANALYSIS.

Obesity is closely associated with various metabolic disorders. However, little is known about abnormalities in the metabolic change of obese adipose tissue. Here we use static metabolic analysis and in vivo metabolic turnover analysis to assess metabolic dynamics in obese mice. The static metabolic analyses showed that glutamate and constitutive metabolites of the TCA cycle were increased in the white adipose tissue (WAT) of ob/ob and diet-induced obesity mice but not in the liver or skeletal muscle of these obese mice. Moreover, in vivo metabolic turnover analyses demonstrated that these glucose-derived metabolites were dynamically and specifically produced in obese WAT compared with lean WAT. Glutamate rise in obese WAT was associated with down-regulation of glutamate aspartate transporter (GLAST), a major glutamate transporter for adipocytes, and low uptake of glutamate into adipose tissue. In adipocytes, glutamate treatment reduced adiponectin secretion and insulin-mediated glucose uptake and phosphorylation of Akt. These data suggest that a high intra-adipocyte glutamate level potentially relates to adipocyte dysfunction in obesity. This study provides novel insights into metabolic dysfunction in obesity through comprehensive application of in vivo metabolic turnover analysis in two obese animal models.

Low muscle quality in Japanese type 2 diabetic patients with visceral fat accumulation.

BACKGROUND: Although obesity-related type 2 diabetes mellitus (T2DM) and sarcopenia in the elderly have been increasing worldwide, the associations among visceral fat accumulation, skeletal muscle indices (mass, strength, and quality) and cardiovascular diseases in T2DM remain poorly investigated. METHODS: We enrolled 183 Japanese T2DM inpatients (126 men, 57 women; mean age 64.7 ± 12.6 years, ± SD). The estimated-visceral fat area (eVFA) and skeletal muscle mass were measured by each device using bioelectrical impedance analysis method. We also measured grip strength by dynamometer and motor nerve conduction velocity (MCV). We analyzed the difference in skeletal muscle indices between T2DM patients with and without visceral fat accumulation, and examined the impact of skeletal muscle indices on cardiovascular diseases in patients with visceral fat accumulation. RESULTS: The prevalence of sarcopenia defined by the Consensus of Asian Working Group for Sarcopenia and low skeletal muscle mass were both lower in the visceral fat accumulation (+) group than in (-) group. However, the prevalence of weak hand grip strength was similar in the visceral fat accumulation (-) and (+) groups, indicating that considerable patients with visceral fat accumulation had weak grip strength in spite of fair skeletal muscle mass. Muscle quality [grip strength (kg)/arm muscle mass (kg)] was significantly lower in patients with visceral fat accumulation. Multiple regression analysis identified eVFA, MCV and sex as significant and independent determinants of muscle quality. In visceral fat accumulation (+) group, the patients with low muscle quality had longer duration of diabetes, lower eGFR, higher serum adiponectin, lower MCV and higher prevalence of cardiovascular diseases, compared to the patients with high muscle quality. Finally, sex- and age-adjusted models showed significant association between low muscle quality and cardiovascular diseases in all subjects (odds ratio 2.28, p = 0.012), especially in patients with visceral fat accumulation (odds ratio 2.72, p = 0.018). CONCLUSIONS: T2DM patients with visceral fat accumulation had low muscle quality, and patients with low muscle quality were more affected with cardiovascular diseases.

Association of Epicardial, Visceral, and Subcutaneous Fat With Cardiometabolic Diseases.

BACKGROUND: Excess of visceral fat is a central factor in the pathogenesis of metabolic syndrome (MetS) and atherosclerosis. However, little is known about how much epicardial fat affects cardiometabolic disorders in comparison with visceral or subcutaneous fat.Methods and Results:Participants suspected as having angina pectoris underwent cardiac computed tomography (CT) imaging. Of them, 374 subjects were analyzed the association of clinical characteristics and CT-based fat distribution measured as epicardial fat volume (EFV), visceral fat area (VFA), and subcutaneous fat area (SFA). EFV was highly associated with VFA (R=0.58). Serum adiponectin was significantly decreased in high VFA subjects (VFA ≥100 cm2) and was also reduced in the high EFV group (EFV ≥80 cm3). Among the low VFA groups, the numbers of subjects with diabetes and coronary atherosclerosis were increased in high EFV group. Among the low EFV groups, the numbers of subjects with diabetes, hyperuricemia, and coronary atherosclerosis were increased among the high VFA subjects. In an age-, sex-, and body mass index (BMI)-adjusted model, EFV was associated with dyslipidemia and MetS, and VFA was significantly associated with hypertension, dyslipidemia, MetS, and coronary atherosclerosis, while SFA was not related with coronary risks and atherosclerosis. CONCLUSIONS: Epicardial fat accumulation may be a risk for coronary atherosclerosis in subjects without visceral fat accumulation. Visceral fat is the strongest risk for cardiometabolic diseases among the 3 types of fat depot.

Impact of visceral fat on gene expression profile in peripheral blood cells in obese Japanese subjects.

BACKGROUND: Visceral fat plays a central role in the development of metabolic syndrome and atherosclerotic cardiovascular diseases. The association of visceral fat accumulation with cardio-metabolic diseases has been reported, but the impact of visceral fat on the gene expression profile in peripheral blood cells remains to be determined. The aim of this study was to determine the effects of visceral fat area (VFA) and subcutaneous fat area (SFA) on the gene expression profile in peripheral blood cells of obese subjects. METHODS: All 17 enrolled subjects were hospitalized to receive diet therapy for obesity (defined as body mass index, BMI, greater than 25 kg/m2). VFA and SFA were measured at the umbilical level by computed tomography (CT). Blood samples were subjected to gene expression profile analysis by using SurePrint G3 Human GE Microarray 8 × 60 k ver. 2.0. The correlation between various clinical parameters, including VFA and SFA, and peripheral blood gene expression levels was analyzed. RESULTS: Among the 17 subjects, 12 had normal glucose tolerance or borderline diabetes, and 5 were diagnosed with type 2 diabetes without medications [glycated hemoglobin (HbA1c); 6.3 ± 1.3%]. The mean BMI, VFA, and SFA were 30.0 ± 5.5 kg/m2, 177 ± 67 and 245 ± 131 cm2, respectively. Interestingly, VFA altered the expression of 1354 genes, including up-regulation of 307 and down-regulation of 1047, under the statistical environment that the parametric false discovery rate (FDR) was less than 0.1. However, no significant effects were noted for SFA or BMI. Gene ontology analysis showed higher prevalence of VFA-associated genes than that of SFA-associated genes, among the genes associated with inflammation, oxidative stress, immune response, lipid metabolism, and glucose metabolism. CONCLUSIONS: Accumulation of visceral fat, but not subcutaneous fat, has a significant impact on the gene expression profile in peripheral blood cells in obese Japanese subjects.

Systemic arteriosclerosis and eating behavior in Japanese type 2 diabetic patients with visceral fat accumulation.

BACKGROUND: Visceral fat accumulation is a major etiological factor in the progression of type 2 diabetes mellitus and atherosclerosis. We described previously visceral fat accumulation and multiple cardiovascular risk factors in a considerable number of Japanese non-obese subjects (BMI <25 kg/m(2)). Here, we investigated differences in systemic arteriosclerosis, serum adiponectin concentration, and eating behavior in type 2 diabetic patients with and without visceral fat accumulation. METHODS: The study subjects were 75 Japanese type 2 diabetes mellitus (age: 64.8 ± 11.5 years, mean ± SD). Visceral fat accumulation represented an estimated visceral fat area of 100 cm(2) using the bioelectrical impedance analysis method. Subjects were divided into two groups; with (n = 53) and without (n = 22) visceral fat accumulation. Systemic arteriosclerosis was scored for four arteries by ultrasonography. Eating behavior was assessed based on The Guideline for Obesity questionnaire issued by the Japan Society for the Study of Obesity. RESULTS: The visceral fat accumulation (+) group showed significantly higher systemic vascular scores and significantly lower serum adiponectin levels than the visceral fat accumulation (-) group. With respect to the eating behavior questionnaire items, (+) patients showed higher values for the total score and many of the major sub-scores than (-) patients. CONCLUSIONS: Type 2 diabetic patients with visceral fat accumulation showed 1) progression of systemic arteriosclerosis, 2) low serum adiponectin levels, and 3) differences in eating behavior, compared to those without visceral fat accumulation. Taken together, the findings highlight the importance of evaluating visceral fat area in type 2 diabetic patients. Furthermore, those with visceral fat accumulation might need to undergo more intensive screening for systemic arteriosclerosis and consider modifying their eating behaviors.

Uric acid secretion from adipose tissue and its increase in obesity.

Obesity is often accompanied by hyperuricemia. However, purine metabolism in various tissues, especially regarding uric acid production, has not been fully elucidated. Here we report, using mouse models, that adipose tissue could produce and secrete uric acid through xanthine oxidoreductase (XOR) and that the production was enhanced in obesity. Plasma uric acid was elevated in obese mice and attenuated by administration of the XOR inhibitor febuxostat. Adipose tissue was one of major organs that had abundant expression and activities of XOR, and adipose tissues in obese mice had higher XOR activities than those in control mice. 3T3-L1 and mouse primary mature adipocytes produced and secreted uric acid into culture medium. The secretion was inhibited by febuxostat in a dose-dependent manner or by gene knockdown of XOR. Surgical ischemia in adipose tissue increased local uric acid production and secretion via XOR, with a subsequent increase in circulating uric acid levels. Uric acid secretion from whole adipose tissue was increased in obese mice, and uric acid secretion from 3T3-L1 adipocytes was increased under hypoxia. Our results suggest that purine catabolism in adipose tissue could be enhanced in obesity.

Development of a miniaturized multi-turn time-of-flight mass spectrometer with a pulsed fast atom bombardment ion source.

A miniaturized multi-turn time-of-flight (TOF) mass spectrometer with a pulsed fast atom bombardment (FAB) ion source (FAB-MULTUM) has been designed and constructed in order to overcome the drawbacks associated with magnetic sector type instruments utilizing a FAB ion source such as size and weight. This instrument consists of a pulsed FAB ion source, a multi-turn TOF mass spectrometer, a detector, vacuum system, and electronic circuits. The size and weight of the system are less than H520 mm x L580 mm x W230 mm and 45 kg (including vacuum pumps and electronic circuits). The achieved resolving power and mass accuracy of this instrument were > 25000 and about 1 ppm, respectively, which are equivalent to those of magnetic sector type instruments, although the size and weight are much smaller than those of magnetic sector type instruments. The experimental results led us to the conclusion that this instrument enables accurate mass measurements and is a powerful tool for the confirmation of synthesized compounds.

Pharmacological HIF-1 activation upregulates extracellular vesicle production synergistically with adiponectin through transcriptional induction and protein stabilization of T-cadherin.

Pharmacological activation of hypoxia-inducible factor 1 (HIF-1), a hypoxia-responsive transcription factor, has attracted increasing attention due to its efficacy not only in renal anemia but also in various disease models. Our study demonstrated that a HIF-1 activator enhanced extracellular vesicle (EV) production from cultured endothelial cells synergistically with adiponectin, an adipocyte-derived factor, through both transcriptional induction and posttranscriptional stabilization of an adiponectin binding partner, T-cadherin. Increased EV levels were observed in wild-type mice but not in T-cadherin null mice after consecutive administration of roxadustat. Adiponectin- and T-cadherin-dependent increased EV production may be involved in the pleiotropic effects of HIF-1 activators.

Vascular complications and changes in body mass index in Japanese type 2 diabetic patients with abdominal obesity.

BACKGROUND: Although many Asian type 2 diabetic patients have been considered to be not obese and have low capacity of insulin secretion, the proportion of obese patients with visceral fat accumulation has increased in recent years. We found previously considerable number of Japanese non-obese subjects (body mass index (BMI) < 25 kg/m²) with visceral fat accumulation and multiple cardiovascular risk factors. The aim of the study was to investigate the difference in clinical features of type 2 diabetic patients with and without visceral fat accumulation, focusing on vascular complications and changes in BMI. METHODS: We enrolled 88 Japanese hospitalized type 2 diabetic patients. Abdominal obesity represented waist circumference (WC) of ≥85 cm for males and ≥90 cm for females (corresponding to visceral fat area of 100 cm²). Subjects were divided into two groups; with or without abdominal obesity. RESULTS: Hypertension, dyslipidemia and cardiovascular diseases were significantly more in the patients with abdominal obesity. The prevalence of cardiovascular disease in the non-obese patients (BMI < 25 kg/m²) with abdominal obesity were similar in obese patients (BMI ≥25 kg/m²). The mean BMI of the patients with abdominal obesity was < 25 kg/m² at 20 years of age, but reached maximum to more than 30 kg/m² in the course. Furthermore, substantial portion of the type 2 diabetic patients (52% in males and 43% in females) were not obese at 20 year-old (BMI < 25 kg/m²), but developed abdominal obesity by the time of admission. CONCLUSION: These results emphasize the need to control multiple risk factors and prevent atherosclerotic disease in patients with abdominal obesity. The significant weight gain after 20 years of age in patients with abdominal obesity stresses the importance of lifestyle modification in younger generation, to prevent potential development of type 2 diabetes and future atherosclerotic cardiovascular disease.

Unique ligand and kinase-independent roles of the insulin receptor in regulation of cell cycle, senescence and apoptosis.

Insulin acts through the insulin receptor (IR) tyrosine kinase to exert its classical metabolic and mitogenic actions. Here, using receptors with either short or long deletion of the ß-subunit or mutation of the kinase active site (K1030R), we have uncovered a second, previously unrecognized IR signaling pathway that is intracellular domain-dependent, but ligand and tyrosine kinase-independent (LYK-I). These LYK-I actions of the IR are linked to changes in phosphorylation of a network of proteins involved in the regulation of extracellular matrix organization, cell cycle, ATM signaling and cellular senescence; and result in upregulation of expression of multiple extracellular matrix-related genes and proteins, down-regulation of immune/interferon-related genes and proteins, and increased sensitivity to apoptosis. Thus, in addition to classical ligand and tyrosine kinase-dependent (LYK-D) signaling, the IR regulates a second, ligand and tyrosine kinase-independent (LYK-I) pathway, which regulates the cellular machinery involved in senescence, matrix interaction and response to extrinsic challenges.

Leucine-973 is a crucial residue differentiating insulin and IGF-1 receptor signaling.

Insulin and IGF-1 receptors (IR and IGF1R) are highly homologous and share similar signaling systems, but each has a unique physiological role, with IR primarily regulating metabolic homeostasis and IGF1R regulating mitogenic control and growth. Here, we show that replacement of a single amino acid at position 973, just distal to the NPEY motif in the intracellular juxtamembrane region, from leucine, which is highly conserved in IRs, to phenylalanine, the highly conserved homologous residue in IGF1Rs, resulted in decreased IRS-1/PI3K/Akt/mTORC1 signaling and increased Shc/Gab1/MAPK cell cycle signaling. As a result, cells expressing L973F-IR exhibited decreased insulin-induced glucose uptake, increased cell growth, and impaired receptor internalization. Mice with knockin of the L973F-IR showed similar alterations in signaling in vivo, and this led to decreased insulin sensitivity, a modest increase in growth, and decreased weight gain when mice were challenged with a high-fat diet. Thus, leucine-973 in the juxtamembrane region of the IR acts as a crucial residue differentiating IR signaling from IGF1R signaling.

HSP47 levels determine the degree of body adiposity.

Adiposity varies among individuals with the influence of diverse physiological, pathological, environmental, hormonal, and genetic factors, but a unified molecular basis remains elusive. Here, we identify HSP47, a collagen-specific chaperone, as a key determinant of body adiposity. HSP47 expression is abundant in adipose tissue; increased with feeding, overeating, and obesity; decreased with fasting, exercise, calorie restriction, bariatric surgery, and cachexia; and correlated with fat mass, BMI, waist, and hip circumferences. Insulin and glucocorticoids, respectively, up- and down-regulate HSP47 expression. In humans, the increase of HSP47 gene expression by its intron or synonymous variants is associated with higher body adiposity traits. In mice, the adipose-specific knockout or pharmacological inhibition of HSP47 leads to lower body adiposity compared to the control. Mechanistically, HSP47 promotes collagen dynamics in the folding, secretion, and interaction with integrin, which activates FAK signaling and preserves PPARγ protein from proteasomal degradation, partly related to MDM2. The study highlights the significance of HSP47 in determining the amount of body fat individually and under various circumstances.

Increased plasma XOR activity induced by NAFLD/NASH and its possible involvement in vascular neointimal proliferation.

Xanthine oxidoreductase (XOR) is an enzyme that catalyzes hypoxanthine to xanthine and xanthine to uric acid, respectively. However, the underlying mechanisms of increased plasma XOR and its pathological roles in systemic diseases, such as atherosclerosis, are not fully understood. In this study, we found that changes in plasma XOR activity after bariatric surgery closely associated with those in liver enzymes, but not with those in BMI. In a mouse model of nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH), plasma XOR activity markedly increased. Besides, purine catabolism was accelerated in the plasma per se of NASH mice and human patients with high XOR activity. In our NASH mice, we observed an increased vascular neointima formation consisting of dedifferentiated vascular smooth muscle cells (SMCs), which was significantly attenuated by topiroxostat, a selective XOR inhibitor. In vitro, human liver S9-derived XOR promoted proliferation of SMCs with phenotypic modulation and induced ROS production by catabolizing hypoxanthine released from human endothelial cells. Collectively, the results from human and mouse models suggest that increased plasma XOR activity, mainly explained by excess hepatic leakage, was involved in the pathogenesis of vascular injury, especially in NAFLD/NASH conditions.

Plasma xanthine oxidoreductase activity in Japanese patients with type 2 diabetes across hospitalized treatment.

AIMS/INTRODUCTION: Xanthine oxidoreductase (XOR) is an enzyme that catalyzes hypoxanthine and xanthine to xanthine and uric acid, respectively. Plasma XOR activity has recently been measured in humans. However, limited information is known about plasma XOR activity in patients with type 2 diabetes mellitus, and its changes after short-term glycemic control treatment. MATERIALS AND METHODS: We enrolled 28 Japanese patients (10 men/18 women) with type 2 diabetes mellitus who were hospitalized to undergo medical treatment for diabetes. Plasma XOR activity, quantified using triple quadrupole mass spectrometry and liquid chromatography, and other clinical parameters were examined at admission and 2 weeks after treatment during hospitalization. Changes in plasma XOR activity after treatment during hospitalization and associated clinical parameters were assessed. RESULTS: At the time of admission, the median plasma XOR activity was 83.1 pmol/h/mL, with a wide range of 14.4-1150 pmol/h/mL. Multiple regression analysis identified serum aspartate transaminase and alanine transaminase levels as significant and independent factors correlating with the baseline plasma XOR. Two weeks of treatment during hospitalization was associated with a significant decrease in plasma XOR activity. Changes in serum aspartate transaminase were also the only significant and independent factor correlating with changes in plasma XOR activity. CONCLUSIONS: A close relationship was observed between plasma XOR activity and liver transaminases in patients with type 2 diabetes mellitus, cross-sectionally, and also across treatment during hospitalization.

Miniaturized high-resolution time-of-flight mass spectrometer MULTUM-S II with an infinite flight path.

A new miniature multiturn time-of-flight (TOF) analyzer "MULTUM-S II" has been designed and constructed. This instrument consists of an electron ionization source, the multiturn TOF ion optics, a detector, vacuum system, and electronic circuits. The multiturn TOF analyzer consists of four electrostatic toroidal sectors and two additional electric toroidal sectors for the purpose of ion injection/ejection. The size and weight of the system is less than 50 cm × 57 cm × 30 cm and 35 kg (including vacuum pumps and electronic circuits). The multiturn TOF analyzer is capable of high mass resolution because of its infinite flight path utilizing perfect space and time focused closed flight orbit. To evaluate the resolution in MULTUM-S II, separation of pyridine (¹²C5H5N) and the isotopic component of benzene (¹³C¹²C5H6) was performed at a mass resolution of about 20,000. Another performance characteristic of the MULTUM-S II was demonstrated by the separation of the greenhouse gas doublet CO2 and N2O (Δm = 0.0113 Da). While the mass difference is a mere 0.01 Da, the instrument could easily separate the two peaks at a calculated mass resolution of 31,600. The MULTUM-S II offers high mass resolution mass spectrometry in a miniaturized/portable enclosure.

Author Correction: Adiponectin promotes muscle regeneration through binding to T-cadherin.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.