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Sample records for higher glucose sensitivity

  1. Ultraviolet sensitivity in higher dimensions

    International Nuclear Information System (INIS)

    Hoover, Doug; Burgess, Clifford P.

    2006-01-01

    We calculate the first three Gilkey-DeWitt (heat-kernel) coefficients, a 0 , a 1 and a 2 , for massive particles having the spins of most physical interest in n dimensions, including the contributions of the ghosts and the fields associated with the appropriate generalized Higgs mechanism. By assembling these into supermultiplets we compute the same coefficients for general supergravity theories, and show that they vanish for many examples. One of the steps of the calculation involves computing these coefficients for massless particles, and our expressions in this case agree with - and extend to more general background spacetimes - earlier calculations, where these exist. Our results give that part of the low-energy effective action which depends most sensitively on the mass of heavy fields once these are integrated out. These results are used in hep-th/0504004 to compute the sensitivity to large masses of the Casimir energy in Ricci-flat 4D compactifications of 6D supergravity

  2. Platinum decorated carbon nanotubes for highly sensitive amperometric glucose sensing

    International Nuclear Information System (INIS)

    Xie Jining; Wang Shouyan; Aryasomayajula, L; Varadan, V K

    2007-01-01

    Fine platinum nanoparticles (1-5 nm in diameter) were deposited on functionalized multi-walled carbon nanotubes (MWNTs) through a decoration technique. A novel type of enzymatic Pt/MWNTs paste-based mediated glucose sensor was fabricated. Electrochemical measurements revealed a significantly improved sensitivity (around 52.7 μA mM -1 cm -2 ) for glucose sensing without using any picoampere booster or Faraday cage. In addition, the calibration curve exhibited a good linearity in the range of 1-28 mM of glucose concentration. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) were performed to investigate the nanoscale structure and the chemical bonding information of the Pt/MWNTs paste-based sensing material, respectively. The improved sensitivity of this novel glucose sensor could be ascribed to its higher electroactive surface area, enhanced electron transfer, efficient enzyme immobilization, unique interaction in nanoscale and a synergistic effect on the current signal from possible multi-redox reactions

  3. Chemical exchange-sensitive spin-lock MRI of glucose analog 3-O-methyl-d-glucose in normal and ischemic brain.

    Science.gov (United States)

    Jin, Tao; Mehrens, Hunter; Wang, Ping; Kim, Seong-Gi

    2018-05-01

    Glucose transport is important for understanding brain glucose metabolism. We studied glucose transport with a presumably non-toxic and non-metabolizable glucose analog, 3-O-methyl-d-glucose, using a chemical exchange-sensitive spin-lock MRI technique at 9.4 Tesla. 3-O-methyl-d-glucose showed comparable chemical exchange properties with d-glucose and 2-deoxy-d-glucose in phantoms, and higher and lower chemical exchange-sensitive spin-lock sensitivity than Glc and 2-deoxy-d-glucose in in vivo experiments, respectively. The changes of the spin-lattice relaxation rate in the rotating frame (Δ R 1 ρ) in normal rat brain peaked at ∼15 min after the intravenous injection of 1 g/kg 3-O-methyl-d-glucose and almost maintained a plateau for >1 h. Doses up to 4 g/kg 3-O-methyl-d-glucose were linearly correlated with Δ R 1 ρ. In rats with focal ischemic stroke, chemical exchange-sensitive spin-lock with 3-O-methyl-d-glucose injection at 1 h after stroke onset showed reduced Δ R 1 ρ in the ischemic core but higher Δ R 1 ρ in the peri-core region compared to normal tissue, which progressed into the ischemic core at 3 h after stroke onset. This suggests that the hyper-chemical exchange-sensitive spin-lock region observed at 1 h is the ischemic penumbra at-risk of infarct. In summary, 3-O-methyl-d-glucose-chemical exchange-sensitive spin-lock can be a sensitive MRI technique to probe the glucose transport in normal and ischemic brains.

  4. The importance of sensitive screening for abnormal glucose metabolism in patients with IgA nephropathy.

    Science.gov (United States)

    Jia, Xiaoyuan; Pan, Xiaoxia; Xie, Jingyuan; Shen, Pingyan; Wang, Zhaohui; Li, Ya; Wang, Weiming; Chen, Nan

    2016-01-01

    To investigate the prevalence of abnormal glucose metabolism, insulin resistance (IR) and the related risk factors in IgA nephropathy (IgAN) patients. We analyzed oral glucose tolerance test (OGTT) and clinical data of 107 IgAN patients and 106 healthy controls. Glucose metabolism, homeostasis model assessment of insulin resistance (HOMA-IR) and the insulin sensitivity index (ISI) of both groups were evaluated. The prevalence of abnormal glucose metabolism was significantly higher in the IgAN group than in the control group (41.12% vs. 9.43%, p glucose, fasting insulin, OGTT 2-hour blood glucose, OGTT 2-hour insulin, HOMA-IR, and lower ISI than healthy controls. Triglyceride (OR = 2.55), 24-hour urine protein excretion (OR = 1.39), and age (OR = 1.06) were independent risk factors for abnormal glucose metabolism in IgAN patients. BMI, eGFR, 24-hour urine protein excretion, triglyceride, fasting blood glucose, fasting insulin, OGTT 2-hour blood glucose, and OGTT 2-hour insulin were significantly higher in IgAN patients with IR than in IgAN patients without IR, while HDL and ISI were significantly lower. BMI, serum albumin, and 24-hour urine protein excretion were correlated factors of IR in IgAN patients. Our study highlighted that abnormal glucose metabolism was common in IgAN patients. Triglyceride and 24-hour urine protein excretion were significant risk factors for abnormal glucose metabolism. Therefore, sensitive screening for glucose metabolism status and timely intervention should be carried out in clinical work.

  5. An extremely sensitive monoboronic acid based fluorescent sensor for glucose

    International Nuclear Information System (INIS)

    Sun Xiangying; Liu Bin; Jiang Yunbao

    2004-01-01

    An extremely sensitive monoboronic acid based fluorescent sensor for glucose was developed. This was carried out by assembling a fluorescent monoboronic acid, 3-aminophenylboronic acid (PBA) indirectly onto gold surface via its electrostatic interaction with cysteine (Cys) that was directly assembled on the gold surface. The formation of self-assembled bilayers (SAB) was confirmed and primarily characterized by cyclic voltammetry and X-ray photoelectron spectra (XPS). The SAB containing PBA was found fluorescent and its fluorescence showed an extremely high sensitivity to the presence of glucose and other monosaccharides such as galactose and fructose with quenching constants at 10 8 M -1 order of magnitude compared to those at 10 2 M -1 in bulk solutions. The quenching constants were found to vary in the order of D-glucose>D-galactose>D-fructose>D-mannose that is different from that in bulk solution which shows the highest binding affinity toward D-fructose and very low sensitivity toward glucose. The reported monoboronic acid based SAB fluorescent sensor showed the highest sensitivity towards glucose with the capacity of detecting saccharides of concentration down to nanomolar level. It was also demonstrated that the fluorescence from PBA/Cys/Au can be easily recovered after each measurement event and therefore also represents a new reusable method for immobilizing reagent in fabricating chemosensors

  6. A highly sensitive electrochemical glucose sensor structuring with nickel hydroxide and enzyme glucose oxidase

    International Nuclear Information System (INIS)

    Mathew, Manjusha; Sandhyarani, N.

    2013-01-01

    Graphical abstract: A combination of Ni 2+ /Ni 3+ redox couple and glucose oxidase has successfully been exploited for the realization of a highly sensitive glucose sensor for the first time. -- Highlights: • A multilayered glucose biosensor with enhanced sensitivity was fabricated. • Combination of Ni 2+ /Ni 3+ redox couple and glucose oxidase has been exploited for the first time. • Exhibits a lower detection limit of 100 nM with a high sensitivity of 16,840 μA mM −1 cm −2 . • The surface shows a low Michaelis–Menten constant value of 2.4 μM. • Detailed mechanism of sensing was proposed and justified. -- Abstract: A multilayered glucose biosensor with enhanced electron transport was fabricated via the sequential electrodeposition of chitosan gold nanocomposite (CGNC) and nickel hydroxide (Ni(OH) 2 ) on a bare gold electrode and subsequent immobilization of glucose oxidase. A thin film of Ni(OH) 2 deposited on CGNC modified gold electrode serves as an electrochemical redox probe as well as a matrix for the immobilization of glucose oxidase retaining its activity. Electron transport property of CGNC has been exploited to enhance the electron transport between the analyte and electrode. Electrochemical characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. Under optimal conditions the biosensor exhibits a linear range from 1 μM to 100 μM with a limit of detection (lod) down to 100 nM. The sensor shows a low Michaelis-Menten constant value of 2.4 μM indicates the high affinity of enzyme to the analyte points to the retained activity of enzyme after immobilization. The present glucose sensor with the high selectivity, sensitivity and stability is promising for practical clinical applications

  7. Effect of training on insulin sensitivity of glucose uptake and lipolysis in human adipose tissue

    DEFF Research Database (Denmark)

    Stallknecht, B; Larsen, J J; Mikines, K J

    2000-01-01

    Training increases insulin sensitivity of both whole body and muscle in humans. To investigate whether training also increases insulin sensitivity of adipose tissue, we performed a three-step hyperinsulinemic, euglycemic clamp in eight endurance-trained (T) and eight sedentary (S) young men...... (glucose only). Adipose tissue blood flow was measured by (133)Xe washout. In the basal state, adipose tissue blood flow tended to be higher in T compared with S subjects, and in both groups blood flow was constant during the clamp. The change from basal in arterial-interstitial glucose concentration......-time: T, 44 +/- 9 min (n = 7); S, 102 +/- 23 min (n = 5); P training enhances insulin sensitivity of glucose uptake in subcutaneous adipose tissue and in skeletal muscle. Furthermore, interstitial glycerol data suggest that training also increases insulin sensitivity of lipolysis...

  8. Modulation of olfactory sensitivity and glucose sensing by the feeding state in obese Zucker rats.

    Directory of Open Access Journals (Sweden)

    Pascaline eAimé

    2014-09-01

    Full Text Available The Zucker fa/fa rat has been widely used as an animal model to study obesity, since it recapitulates most of its behavioral and metabolic dysfunctions, such as hyperphagia, hyperglycemia and insulin resistance. Although it is well established that olfaction is under nutritional and hormonal influences, little is known about the impact of metabolic dysfunctions on olfactory performances and glucose-sensing in the olfactory system of the obese Zucker rat. In the present study, using a behavioral paradigm based on a conditioned olfactory aversion, we have shown that both obese and lean Zucker rats have a better olfactory sensitivity when they are fasted than when they are satiated. Interestingly, the obese Zucker rats displayed a higher olfactory sensitivity than their lean controls. By investigating the molecular mechanisms involved in glucose-sensing in the olfactory system, we demonstrated that sodium-coupled glucose transporters 1 (SGLT1 and insulin dependent glucose transporters 4 (GLUT4 are both expressed in the olfactory bulb (OB. By comparing the expression of GLUT4 and SGLT1 in OB of obese and lean Zucker rats, we found that only SGLT1 is regulated in genotype-dependent manner. Next, we used glucose oxidase biosensors to simultaneously measure in vivo the extracellular fluid glucose concentrations ([Gluc]ECF in the OB and the cortex. Under metabolic steady state, we have determined that the OB contained twice the amount of glucose found in the cortex. In both regions, the [Gluc]ECF was 2 fold higher in obese rats compared to their lean controls. Under induced dynamic glycemia conditions, insulin injection produced a greater decrease of [Gluc]ECF in the OB than in the cortex. Glucose injection did not affect OB [Gluc]ECF in Zucker fa/fa rats. In conclusion, these results emphasize the importance of glucose for the OB network function and provide strong arguments towards establishing the OB glucose-sensing as a key factor for sensory

  9. Insulin sensitivity and secretion in Arab Americans with glucose intolerance.

    Science.gov (United States)

    Salinitri, Francine D; Pinelli, Nicole R; Martin, Emily T; Jaber, Linda A

    2013-12-01

    This study examined the pathophysiological abnormalities in Arab Americans with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). Homeostasis model assessment of insulin resistance (HOMA-IR), homeostasis model assessment of insulin secretion (HOMA-%β), and the Matsuda Insulin Sensitivity Index composite (ISIcomposite) were calculated from the fasting and stimulated glucose and insulin concentrations measured during the oral glucose tolerance test in a population-based, representative, cross-sectional sample of randomly selected Arab Americans. In total, 497 individuals (42±14 years old; 40% males; body mass index [BMI], 29±6 kg/m(2)) were studied. Multivariate linear regression models were performed to compare HOMA-IR, HOMA-%β, and ISIcomposite among individuals with normal glucose tolerance (NGT) (n=191) versus isolated IFG (n=136), isolated IGT (n=22), combined IFG/IGT (n=43), and diabetes (n=105). Compared with individuals with NGT (2.9±1.6), HOMA-IR progressively increased in individuals with isolated IFG (4.8±2.7, Psex and BMI, these associations remained unchanged. Whole-body insulin sensitivity as measured by ISIcomposite was significantly lower in individuals with isolated IFG (3.9±2.3, Psex, and BMI, isolated IFG (146.6±80.2) was also significantly associated with a decline in HOMA-%β relative to NGT (P=0.005). This study suggests that differences in the underlying metabolic defects leading to diabetes in Arab Americans with IFG and/or IGT exist and may require different strategies for the prevention of diabetes.

  10. Higher transport and metabolism of glucose in astrocytes compared with neurons: a multiphoton study of hippocampal and cerebellar tissue slices.

    Science.gov (United States)

    Jakoby, Patrick; Schmidt, Elke; Ruminot, Iván; Gutiérrez, Robin; Barros, L Felipe; Deitmer, Joachim W

    2014-01-01

    Glucose is the most important energy substrate for the brain, and its cellular distribution is a subject of great current interest. We have employed fluorescent glucose probes, the 2-deoxy-D-glucose derivates 6- and 2-([N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose) (2-NBDG), to measure transport and metabolism of glucose in acute slices of mouse hippocampus and cerebellum. In the hippocampus, 6-NBDG, which is not metabolized and hence indicates glucose transport, was taken up faster in astrocyte-rich layers (Stratum radiatum [S.r.], Stratum oriens [S.o.]) than in pyramidal cells. Metabolizable 2-NBDG showed larger signals in S.r. and S.o. than in Stratum pyramidale, suggesting faster glucose utilization rate in the astrocyte versus the neuronal compartment. Similarly, we found higher uptake and temperature-sensitive metabolism of 2-NBDG in Bergmann glia when compared with adjacent Purkinje neurons of cerebellar slices. A comparison between 6-NBDG transport and glucose transport in cultured cells using a fluorescence resonance energy transfer nanosensor showed that relative to glucose, 6-NBDG is transported better by neurons than by astrocytes. These results indicate that the preferential transport and metabolism of glucose by glial cells versus neurons proposed for the hippocampus and cerebellum by ourselves (in vitro) and for the barrel cortex by Chuquet et al. (in vivo) is more pronounced than anticipated.

  11. Fabrication of CuO nanoplatelets for highly sensitive enzyme-free determination of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Wang Juan [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China); Zhang Weide, E-mail: zhangwd@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China)

    2011-09-01

    Highlights: > Adhered growth of CuO nanoplatelets on Cu foils. > Enzyme-free glucose sensor with very high sensitivity. > Excellent stability and good anti-interference ability. - Abstract: CuO nanoplatelets were grown on Cu foils by a one step, template free process. The structure and morphology of the CuO nanoplatelets were characterized by X-ray diffraction, scanning and transmission electron microscopy. The CuO nanoplatelets grown on Cu foil were integrated to be an electrode for glucose sensing. The electrocatalytic activity of the CuO nanoplatelets electrode for glucose in alkaline media was investigated by cyclic voltammetry and chronoamperometry. The electrode exhibits a sensitivity of 3490.7 {mu}A mM{sup -1} cm{sup -2} to glucose which is much higher than that of most reported enzyme-free glucose sensors and the linear range was obtained over a concentration up to 0.80 mM with a detection limit of 0.50 {mu}M (signal/noise = 3). Exhilaratingly, the electrode based on the CuO nanoplatelets is resistant against poisoning by chloride ion, and the interference from the oxidation of common interfering species, such as uric acid, ascorbic acid, dopamine and carbonhydrate compounds, can also be effectively avoided. Finally, the electrode was applied to analyze glucose concentration in human serum samples.

  12. Prediction of clamp-derived insulin sensitivity from the oral glucose insulin sensitivity index

    DEFF Research Database (Denmark)

    Tura, Andrea; Chemello, Gaetano; Szendroedi, Julia

    2018-01-01

    that underwent both a clamp and an OGTT or meal test, thereby allowing calculation of both the M value and OGIS. The population was divided into a training and a validation cohort (n = 359 and n = 154, respectively). After a stepwise selection approach, the best model for M value prediction was applied......AIMS/HYPOTHESIS: The euglycaemic-hyperinsulinaemic clamp is the gold-standard method for measuring insulin sensitivity, but is less suitable for large clinical trials. Thus, several indices have been developed for evaluating insulin sensitivity from the oral glucose tolerance test (OGTT). However......, most of them yield values different from those obtained by the clamp method. The aim of this study was to develop a new index to predict clamp-derived insulin sensitivity (M value) from the OGTT-derived oral glucose insulin sensitivity index (OGIS). METHODS: We analysed datasets of people...

  13. Higher insulin sensitivity in vegans is not associated with higher mitochondrial density.

    Science.gov (United States)

    Gojda, J; Patková, J; Jaček, M; Potočková, J; Trnka, J; Kraml, P; Anděl, M

    2013-12-01

    Vegans have a lower incidence of insulin resistance (IR)-associated diseases and a higher insulin sensitivity (IS) compared with omnivores. The aim of this study was to examine whether the higher IS in vegans relates to markers of mitochondrial biogenesis and to intramyocellular lipid (IMCL) content. Eleven vegans and 10 matched (race, age, sex, body mass index, physical activity and energy intake) omnivorous controls were enrolled in a case-control study. Anthropometry, bioimpedance (BIA), ultrasound measurement of visceral and subcutaneous fat layer, parameters of glucose and lipid homeostasis, hyperinsulinemic euglycemic clamp and muscle biopsies were performed. Citrate synthase (CS) activity, mitochondrial DNA (mtDNA) and IMCL content were assessed in skeletal muscle samples. Both groups were comparable in anthropometric and BIA parameters, physical activity and protein-energy intake. Vegans had significantly higher glucose disposal (M-value, vegans 8.11±1.51 vs controls 6.31±1.57 mg/kg/min, 95% confidence interval: 0.402 to 3.212, P=0.014), slightly lower IMCL content (vegans 13.91 (7.8 to 44.0) vs controls 17.36 (12.4 to 78.5) mg/g of muscle, 95% confidence interval: -7.594 to 24.550, P=0.193) and slightly higher relative muscle mtDNA amount (vegans 1.36±0.31 vs controls 1.13±0.36, 95% confidence interval:-0.078 to 0.537, P=0.135). No significant differences were found in CS activity (vegans 18.43±5.05 vs controls 18.16±5.41 μmol/g/min, 95% confidence interval: -4.503 to 5.050, P=0.906). Vegans have a higher IS, but comparable mitochondrial density and IMCL content with omnivores. This suggests that a decrease in whole-body glucose disposal may precede muscle lipid accumulation and mitochondrial dysfunction in IR development.

  14. Higher Endogenous Glucose Production during OGTT vs Isoglycemic Intravenous Glucose Infusion

    DEFF Research Database (Denmark)

    Lund, Asger; Bagger, Jonatan I; Christensen, Mikkel Bring

    2016-01-01

    CONTEXT: Oral glucose ingestion elicits a larger insulin response and delayed suppression of glucagon compared to isoglycemic intravenous (iv) glucose infusion (IIGI). OBJECTIVE: We studied whether these differences translate into effects on endogenous glucose production (EGP) and glucose disposal......); HbA1c 53.8 ± 11.0 mmol/mol; duration of diabetes 9.2 ± 5.0 years) and 10 matched non-diabetic control subjects (age 56.0±10.7 years; BMI 29.8 ± 2.9 kg/m(2); HbA1c 33.8 ± 5.5 mmol/mol) Interventions: Three experimental days: 75 g-oral glucose tolerance test (OGTT), IIGI and IIGI+glucagon (IIGI...

  15. Insulin Sensitivity and Glucose Homeostasis Can Be Influenced by Metabolic Acid Load

    Directory of Open Access Journals (Sweden)

    Lucio Della Guardia

    2018-05-01

    Full Text Available Recent epidemiological findings suggest that high levels of dietary acid load can affect insulin sensitivity and glucose metabolism. Consumption of high protein diets results in the over-production of metabolic acids which has been associated with the development of chronic metabolic disturbances. Mild metabolic acidosis has been shown to impair peripheral insulin action and several epidemiological findings suggest that metabolic acid load markers are associated with insulin resistance and impaired glycemic control through an interference intracellular insulin signaling pathways and translocation. In addition, higher incidence of diabetes, insulin resistance, or impaired glucose control have been found in subjects with elevated metabolic acid load markers. Hence, lowering dietary acid load may be relevant for improving glucose homeostasis and prevention of type 2 diabetes development on a long-term basis. However, limitations related to patient acid load estimation, nutritional determinants, and metabolic status considerably flaws available findings, and the lack of solid data on the background physiopathology contributes to the questionability of results. Furthermore, evidence from interventional studies is very limited and the trials carried out report no beneficial results following alkali supplementation. Available literature suggests that poor acid load control may contribute to impaired insulin sensitivity and glucose homeostasis, but it is not sufficiently supportive to fully elucidate the issue and additional well-designed studies are clearly needed.

  16. Switching an O2 sensitive glucose oxidase bioelectrode into an almost insensitive one by cofactor redesign.

    Science.gov (United States)

    Tremey, Emilie; Suraniti, Emmanuel; Courjean, Olivier; Gounel, Sébastien; Stines-Chaumeil, Claire; Louerat, Frédéric; Mano, Nicolas

    2014-06-04

    In the 5-8 mM glucose concentration range, of particular interest for diabetes management, glucose oxidase bioelectrodes are O2 dependent, which decrease their efficiencies. By replacing the natural cofactor of glucose oxidase, we succeeded in turning an O2 sensitive bioelectrode into an almost insensitive one.

  17. Dissociation of in vitro sensitivities of glucose transport and antilipolysis to insulin in NIDDM

    International Nuclear Information System (INIS)

    Yki-Jaervinen, H.; Kubo, K.; Zawadzki, J.; Lillioja, S.; Young, A.; Abbott, W.; Foley, J.E.

    1987-01-01

    It is unclear from previous studies whether qualitative or only quantitative differences exist in insulin action in adipocytes obtained from obese subjects with non-insulin-dependent diabetes mellitus (NIDDM) when compared with equally obese nondiabetic subjects. In addition, the role of changes in insulin binding as a cause of insulin resistance in NIDDM is still controversial. The authors compared the sensitivities of [ 14 C]-glucose transport and antilipolysis to insulin and measured [ 125 I]-insulin binding in abdominal adipocytes obtained from 45 obese nondiabetic, obese diabetic, and 15 nonobese female southwestern American Indians. Compared with the nonobese group, the sensitivities of glucose transport antilipolysis were reduced in both the obese nondiabetic and obese diabetic groups. Compared with the obese nondiabetic subjects, the ED 50 for stimulation of glucose transport was higher in the obese patients with NIDDM. In contrast, the ED 50 S for antilipolysis were similar in obese diabetic patients and obese nondiabetic subjects. No differences was found in insulin binding in patients with NIDDM when compared with the equally obese nondiabetic subjects. These data indicate 1) the mechanism of insulin resistance differs in NIDDM and obesity, and 2) the selective loss of insulin sensitivity in NIDDM precludes changes in insulin binding as a cause of insulin resistance in this disorder

  18. MIL-53(Fe) MOF-mediated catalytic chemiluminescence for sensitive detection of glucose.

    Science.gov (United States)

    Yi, Xueling; Dong, Wenfei; Zhang, Xiaodan; Xie, Jianxin; Huang, Yuming

    2016-12-01

    Various analytical applications of metal-organic frameworks (MOFs) have been rapidly developed in the past few years. However, the employment of MOFs as catalysts in chemiluminescence (CL) analysis is rare. Here, for the first time, we found that MIL-53(Fe) MOFs could significantly enhance the CL of luminol in the presence of H 2 O 2 in an alkaline medium. The CL intensity in the luminol-H 2 O 2 -MIL-53(Fe) system was about 20 times higher than that in the luminol-H 2 O 2 system. Moreover, the XRD pattern of MIL-53(Fe) after CL reaction was almost the same as that of the original MIL-53(Fe), confirming the catalytic role of MIL-53(Fe) in the luminol-H 2 O 2 -MIL-53(Fe) system. The possible mechanism behind the enhancing phenomenon was discussed based on the results from the CL spectra, FL probe experiments, and active oxygen species measurements. By coupling with the glucose oxidase-based catalytic oxidation reaction, a sensitive and selective CL method was developed for the detection of glucose. There is a linear relationship between the logarithm of CL intensity and the logarithm of glucose concentration in the range from 0.1 to 10 μM, and a detection limit of 0.05 μM (S/N = 3) is obtained. The proposed method has been applied to the determination of glucose in human serum samples with satisfactory results. Graphical abstract MIL-53(Fe) MOFs are found to greatly enhance the chemiluminescence emission of the luminol-H 2 O 2 system, and this finding resulted in a new chemiluminescence method for biosensing of glucose when coupled with the glucose oxidase.

  19. Dysregulated hepatic expression of glucose transporters in chronic disease: contribution of semicarbazide-sensitive amine oxidase to hepatic glucose uptake.

    Science.gov (United States)

    Karim, Sumera; Liaskou, Evaggelia; Fear, Janine; Garg, Abhilok; Reynolds, Gary; Claridge, Lee; Adams, David H; Newsome, Philip N; Lalor, Patricia F

    2014-12-15

    Insulin resistance is common in patients with chronic liver disease (CLD). Serum levels of soluble vascular adhesion protein-1 (VAP-1) are also increased in these patients. The amine oxidase activity of VAP-1 stimulates glucose uptake via translocation of transporters to the cell membrane in adipocytes and smooth muscle cells. We aimed to document human hepatocellular expression of glucose transporters (GLUTs) and to determine if VAP-1 activity influences receptor expression and hepatic glucose uptake. Quantitative PCR and immunocytochemistry were used to study human liver tissue and cultured cells. We also used tissue slices from humans and VAP-1-deficient mice to assay glucose uptake and measure hepatocellular responses to stimulation. We report upregulation of GLUT1, -3, -5, -6, -7, -8, -9, -10, -11, -12, and -13 in CLD. VAP-1 expression and enzyme activity increased in disease, and provision of substrate to hepatic VAP-1 drives hepatic glucose uptake. This effect was sensitive to inhibition of VAP-1 and could be recapitulated by H2O2. VAP-1 activity also altered expression and subcellular localization of GLUT2, -4, -9, -10, and -13. Therefore, we show, for the first time, alterations in hepatocellular expression of glucose and fructose transporters in CLD and provide evidence that the semicarbazide-sensitive amine oxidase activity of VAP-1 modifies hepatic glucose homeostasis and may contribute to patterns of GLUT expression in chronic disease. Copyright © 2014 the American Physiological Society.

  20. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

    Directory of Open Access Journals (Sweden)

    Xuemei Shi

    2017-11-01

    Conclusions: We conclude that acute activation of PPG neurons in the brainstem reduces basal glucose production, enhances intraperitoneal glucose tolerance, and augments hepatic insulin sensitivity, suggesting an important physiological role of PPG neurons-mediated circuitry in promoting glycemic control and insulin sensitivity.

  1. Graphene Quantum Dots Electrochemistry and Sensitive Electrocatalytic Glucose Sensor Development

    Directory of Open Access Journals (Sweden)

    Sanju Gupta

    2017-09-01

    Full Text Available Graphene quantum dots (GQDs, derived from functionalized graphene precursors are graphene sheets a few nanometers in the lateral dimension having a several-layer thickness. They are zero-dimensional materials with quantum confinement and edge site effects. Intense research interest in GQDs is attributed to their unique physicochemical phenomena arising from the sp2-bonded carbon nanocore surrounded with edged plane functional moieties. In this work, GQDs are synthesized by both solvothermal and hydrothermal techniques, with the optimal size of 5 nm determined using high-resolution transmission electron microscopy, with additional UV-Vis absorption and fluorescence spectroscopy, revealing electronic band signatures in the blue-violet region. Their potential in fundamental (direct electron transfer and applied (enzyme-based glucose biosensor electrochemistry has been practically realized. Glucose oxidase (GOx was immobilized on glassy carbon (GC electrodes modified with GQDs and functionalized graphene (graphene oxide and reduced form. The cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy are used for characterizing the direct electron transfer kinetics and electrocatalytical biosensing. The well-defined quasi-reversible redox peaks were observed under various electrochemical environment and conditions (pH, concentration, scan rate to determine the diffusion coefficient (D and first-order electron transfer rate (kET. The cyclic voltammetry curves showed homogeneous ion transport behavior for GQD and other graphene-based samples with D ranging between 8.45 × 10−9 m2 s−1 and 3 × 10−8 m2 s−1 following the order of GO < rGO < GQD < GQD (with FcMeOH as redox probe < GOx/rGO < GOx/GO < HRP/GQDs < GOx/GQDs. The developed GOx-GQDs biosensor responds efficiently and linearly to the presence of glucose over concentrations ranging between 10 μM and 3 mM with a limit of detection of 1.35 μM and

  2. Subthalamic nucleus stimulation does not influence basal glucose metabolism or insulin sensitivity in patients with Parkinson's disease.

    Science.gov (United States)

    Lammers, Nicolette M; Sondermeijer, Brigitte M; Twickler, Th B Marcel; de Bie, Rob M; Ackermans, Mariëtte T; Fliers, Eric; Schuurman, P Richard; La Fleur, Susanne E; Serlie, Mireille J

    2014-01-01

    Animal studies have shown that central dopamine signaling influences glucose metabolism. As a first step to show this association in an experimental setting in humans, we studied whether deep brain stimulation (DBS) of the subthalamic nucleus (STN), which modulates the basal ganglia circuitry, alters basal endogenous glucose production (EGP) or insulin sensitivity in patients with Parkinson's disease (PD). We studied 8 patients with PD treated with DBS STN, in the basal state and during a hyperinsulinemic euglycemic clamp using a stable glucose isotope, in the stimulated and non-stimulated condition. We measured EGP, hepatic insulin sensitivity, peripheral insulin sensitivity (Rd), resting energy expenditure (REE), glucoregulatory hormones, and Parkinson symptoms, using the Unified Parkinson's Disease Rating Scale (UPDRS). Basal plasma glucose and EGP did not differ between the stimulated and non-stimulated condition. Hepatic insulin sensitivity was similar in both conditions and there were no significant differences in Rd and plasma glucoregulatory hormones between DBS on and DBS off. UPDRS was significantly higher in the non-stimulated condition. DBS of the STN in patients with PD does not influence basal EGP or insulin sensitivity. These results suggest that acute modulation of the motor basal ganglia circuitry does not affect glucose metabolism in humans.

  3. Highly Selective and Sensitive Self-Powered Glucose Sensor Based on Capacitor Circuit.

    Science.gov (United States)

    Slaughter, Gymama; Kulkarni, Tanmay

    2017-05-03

    Enzymatic glucose biosensors are being developed to incorporate nanoscale materials with the biological recognition elements to assist in the rapid and sensitive detection of glucose. Here we present a highly sensitive and selective glucose sensor based on capacitor circuit that is capable of selectively sensing glucose while simultaneously powering a small microelectronic device. Multi-walled carbon nanotubes (MWCNTs) is chemically modified with pyrroloquinoline quinone glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BOD) at anode and cathode, respectively, in the biofuel cell arrangement. The input voltage (as low as 0.25 V) from the biofuel cell is converted to a stepped-up power and charged to the capacitor to the voltage of 1.8 V. The frequency of the charge/discharge cycle of the capacitor corresponded to the oxidation of glucose. The biofuel cell structure-based glucose sensor synergizes the advantages of both the glucose biosensor and biofuel cell. In addition, this glucose sensor favored a very high selectivity towards glucose in the presence of competing and non-competing analytes. It exhibited unprecedented sensitivity of 37.66 Hz/mM.cm 2 and a linear range of 1 to 20 mM. This innovative self-powered glucose sensor opens new doors for implementation of biofuel cells and capacitor circuits for medical diagnosis and powering therapeutic devices.

  4. Pre-gravid physical activity and reduced risk of glucose intolerance in pregnancy: the role of insulin sensitivity.

    Science.gov (United States)

    Retnakaran, Ravi; Qi, Ying; Sermer, Mathew; Connelly, Philip W; Zinman, Bernard; Hanley, Anthony J G

    2009-04-01

    Pre-gravid physical activity has been associated with a reduced risk of gestational diabetes mellitus (GDM), although neither the types of exercise nor the physiologic mechanisms underlying this protective effect have been well-studied. Thus, we sought to study the relationships between types of pre-gravid physical activity and metabolic parameters in pregnancy, including glucose tolerance, insulin sensitivity and beta-cell function. A total of 851 women underwent a glucose challenge test (GCT) and a 3-h oral glucose tolerance test (OGTT) in late pregnancy, yielding four glucose tolerance groups: (i) GDM; (ii) gestational impaired glucose tolerance (GIGT); (iii) abnormal GCT with normal glucose tolerance on OGTT (abnormal GCT NGT); and (iv) normal GCT with NGT on OGTT (normal GCT NGT). Pre-gravid physical activity was assessed using the Baecke questionnaire, which measures (i) total physical activity and (ii) its three component domains: work, nonsport leisure-time, and vigorous/sports activity. Glucose tolerance status improved across increasing quartiles of pre-gravid total physical activity (P = 0.0244). Whereas neither work nor nonsport leisure-time activity differed between glucose tolerance groups, pre-gravid vigorous/sports activity was significantly higher in women with normal GCT NGT compared to women with (i) abnormal GCT NGT (P = 0.0018) (ii) GIGT (P = 0.0025), and (iii) GDM (P = 0.0044). In particular, vigorous/sports activity correlated with insulin sensitivity (measured by IS(OGTT)) (r = 0.21, P sports activity emerged as a significant independent predictor of IS(OGTT) in pregnancy (t = 4.97, P sports activity is associated with a reduced risk of glucose intolerance in pregnancy, an effect likely mediated by enhanced insulin sensitivity.

  5. Metabolic determinants of cancer cell sensitivity to glucose limitation and biguanides

    Science.gov (United States)

    Birsoy, Kıvanç; Possemato, Richard; Lorbeer, Franziska K.; Bayraktar, Erol C.; Thiru, Prathapan; Yucel, Burcu; Wang, Tim; Chen, Walter W.; Clish, Clary B.; Sabatini, David M.

    2014-04-01

    As the concentrations of highly consumed nutrients, particularly glucose, are generally lower in tumours than in normal tissues, cancer cells must adapt their metabolism to the tumour microenvironment. A better understanding of these adaptations might reveal cancer cell liabilities that can be exploited for therapeutic benefit. Here we developed a continuous-flow culture apparatus (Nutrostat) for maintaining proliferating cells in low-nutrient media for long periods of time, and used it to undertake competitive proliferation assays on a pooled collection of barcoded cancer cell lines cultured in low-glucose conditions. Sensitivity to low glucose varies amongst cell lines, and an RNA interference (RNAi) screen pinpointed mitochondrial oxidative phosphorylation (OXPHOS) as the major pathway required for optimal proliferation in low glucose. We found that cell lines most sensitive to low glucose are defective in the OXPHOS upregulation that is normally caused by glucose limitation as a result of either mitochondrial DNA (mtDNA) mutations in complex I genes or impaired glucose utilization. These defects predict sensitivity to biguanides, antidiabetic drugs that inhibit OXPHOS, when cancer cells are grown in low glucose or as tumour xenografts. Notably, the biguanide sensitivity of cancer cells with mtDNA mutations was reversed by ectopic expression of yeast NDI1, a ubiquinone oxidoreductase that allows bypass of complex I function. Thus, we conclude that mtDNA mutations and impaired glucose utilization are potential biomarkers for identifying tumours with increased sensitivity to OXPHOS inhibitors.

  6. Glucose-Sensitive Hydrogel Optical Fibers Functionalized with Phenylboronic Acid.

    Science.gov (United States)

    Yetisen, Ali K; Jiang, Nan; Fallahi, Afsoon; Montelongo, Yunuen; Ruiz-Esparza, Guillermo U; Tamayol, Ali; Zhang, Yu Shrike; Mahmood, Iram; Yang, Su-A; Kim, Ki Su; Butt, Haider; Khademhosseini, Ali; Yun, Seok-Hyun

    2017-04-01

    Hydrogel optical fibers are utilized for continuous glucose sensing in real time. The hydrogel fibers consist of poly(acrylamide-co-poly(ethylene glycol) diacrylate) cores functionalized with phenylboronic acid. The complexation of the phenylboronic acid and cis-diol groups of glucose enables reversible changes of the hydrogel fiber diameter. The analyses of light propagation loss allow for quantitative glucose measurements within the physiological range. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A novel insulin resistance index to monitor changes in insulin sensitivity and glucose tolerance: the ACT NOW study.

    Science.gov (United States)

    Tripathy, Devjit; Cobb, Jeff E; Gall, Walter; Adam, Klaus-Peter; George, Tabitha; Schwenke, Dawn C; Banerji, MaryAnn; Bray, George A; Buchanan, Thomas A; Clement, Stephen C; Henry, Robert R; Kitabchi, Abbas E; Mudaliar, Sunder; Ratner, Robert E; Stentz, Frankie B; Reaven, Peter D; Musi, Nicolas; Ferrannini, Ele; DeFronzo, Ralph A

    2015-05-01

    The objective was to test the clinical utility of Quantose M(Q) to monitor changes in insulin sensitivity after pioglitazone therapy in prediabetic subjects. Quantose M(Q) is derived from fasting measurements of insulin, α-hydroxybutyrate, linoleoyl-glycerophosphocholine, and oleate, three nonglucose metabolites shown to correlate with insulin-stimulated glucose disposal. Participants were 428 of the total of 602 ACT NOW impaired glucose tolerance (IGT) subjects randomized to pioglitazone (45 mg/d) or placebo and followed for 2.4 years. At baseline and study end, fasting plasma metabolites required for determination of Quantose, glycated hemoglobin, and oral glucose tolerance test with frequent plasma insulin and glucose measurements to calculate the Matsuda index of insulin sensitivity were obtained. Pioglitazone treatment lowered IGT conversion to diabetes (hazard ratio = 0.25; 95% confidence interval = 0.13-0.50; P < .0001). Although glycated hemoglobin did not track with insulin sensitivity, Quantose M(Q) increased in pioglitazone-treated subjects (by 1.45 [3.45] mg·min(-1)·kgwbm(-1)) (median [interquartile range]) (P < .001 vs placebo), as did the Matsuda index (by 3.05 [4.77] units; P < .0001). Quantose M(Q) correlated with the Matsuda index at baseline and change in the Matsuda index from baseline (rho, 0.85 and 0.79, respectively; P < .0001) and was progressively higher across closeout glucose tolerance status (diabetes, IGT, normal glucose tolerance). In logistic models including only anthropometric and fasting measurements, Quantose M(Q) outperformed both Matsuda and fasting insulin in predicting incident diabetes. In IGT subjects, Quantose M(Q) parallels changes in insulin sensitivity and glucose tolerance with pioglitazone therapy. Due to its strong correlation with improved insulin sensitivity and its ease of use, Quantose M(Q) may serve as a useful clinical test to identify and monitor therapy in insulin-resistant patients.

  8. Effects of turtle oil on insulin sensitivity and glucose metabolism in insulin resistant cell model

    International Nuclear Information System (INIS)

    Bai Jing; Tian Yaping; Guo Duo

    2007-01-01

    To evaluate the effects of turtle oil on insulin sensitivity and glucose metabolism in an insulin-resistant (IR) cell model which was established by the way of high concentration of insulin induction with HepG 2 cell in vitro culture. The IR cells were treated by turtle oil, the glucose consumption and 3 H-D-glucose incorporation rate in IR cells were detected by the way of glucose oxidase and 3 H-D-glucose incorporation assay respectively. The state of cell proliferation was tested by MTT method. The results showed that the incorporation rate of 3 H-D-glucose in IR cells was significantly lower than that in the control cells(P 3 H-D-glucose incorporation rate in either IR cells or control cells was increased with the increase of insulin concentration. Moreover, the 3 H-D-glucose incorporation rate of IR cells increased slower than that of control cells. The MTT assay showed that turtle oil can promote the proliferation of IR cell and control cell. The glucose uptake and glucose consumption in IR cell which treated with turtle oil was significantly increase than that in the control cells (P<0.05). Turtle oil can improve the insulin sensitivity and glucose metabolism in the IR cell model. (authors)

  9. Higher fasting glucose is associated with poorer cognition among healthy young adults.

    Science.gov (United States)

    Hawkins, Misty A W; Gunstad, John; Calvo, Dayana; Spitznagel, Mary Beth

    2016-02-01

    Obesity is associated with cognitive deficits; however, the mechanisms are unclear, especially among otherwise healthy adults. Our objectives were to examine (a) whether obesity is linked to elevations in fasting glucose and (b) whether these elevations are associated with cognitive impairment among otherwise healthy young adults. Participants were 35 normal weight adults and 35 young adults with obesity who completed a task from the Automated Neuropsychological Assessment Metrics-4 (ANAM-4). Measured body mass index (BMI) and fasting blood glucose levels (mg/dL) were examined. Persons with obesity had higher fasting glucose levels than normal weight persons (p = .03). After applying Bonferroni correction for multiple tests, higher fasting glucose predicted less accurate performance on tests of inhibitory control: Go/No-Go Commission Errors (β = .33, p = .004). No effects were observed for sustained attention or working memory (ps ≥. 049). Persons with glucose levels in the prediabetes range had nearly twice as many errors as those with normal glucose, a large effect that was independent of BMI. Young adults who were obese but otherwise healthy had higher fasting glucose levels compared with normal weight peers. Higher glucose levels were associated with poorer cognitive performance on tests of inhibitory control, especially among individuals with prediabetes levels. Thus, subclinical elevations in blood glucose may contribute to cognitive impairment and, ultimately, greater impulsivity-well in advance of the development of chronic disease states (e.g., insulin resistance or Type 2 diabetes) and independently of excess adiposity--though prospective studies are needed to determine directionality of this relationship. (c) 2016 APA, all rights reserved).

  10. Higher glucose levels associated with lower memory and reduced hippocampal microstructure.

    Science.gov (United States)

    Kerti, Lucia; Witte, A Veronica; Winkler, Angela; Grittner, Ulrike; Rujescu, Dan; Flöel, Agnes

    2013-11-12

    For this cross-sectional study, we aimed to elucidate whether higher glycosylated hemoglobin (HbA1c) and glucose levels exert a negative impact on memory performance and hippocampal volume and microstructure in a cohort of healthy, older, nondiabetic individuals without dementia. In 141 individuals (72 women, mean age 63.1 years ± 6.9 SD), memory was tested using the Rey Auditory Verbal Learning Test. Peripheral levels of fasting HbA1c, glucose, and insulin and 3-tesla MRI scans were acquired to assess hippocampal volume and microstructure, as indicated by gray matter barrier density. Linear regression and simple mediation models were calculated to examine associations among memory, glucose metabolism, and hippocampal parameters. Lower HbA1c and glucose levels were significantly associated with better scores in delayed recall, learning ability, and memory consolidation. In multiple regression models, HbA1c remained strongly associated with memory performance. Moreover, mediation analyses indicated that beneficial effects of lower HbA1c on memory are in part mediated by hippocampal volume and microstructure. Our results indicate that even in the absence of manifest type 2 diabetes mellitus or impaired glucose tolerance, chronically higher blood glucose levels exert a negative influence on cognition, possibly mediated by structural changes in learning-relevant brain areas. Therefore, strategies aimed at lowering glucose levels even in the normal range may beneficially influence cognition in the older population, a hypothesis to be examined in future interventional trials.

  11. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity.

    Science.gov (United States)

    Shi, Xuemei; Chacko, Shaji; Li, Feng; Li, Depei; Burrin, Douglas; Chan, Lawrence; Guan, Xinfu

    2017-11-01

    Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. We generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected excitatory hM3Dq-mCherry AAV into their brainstem NTS. We characterized the metabolic impact of PPG neuron activation on glucose homeostasis and insulin sensitivity using stable isotopic tracers coupled with hyperinsulinemic euglycemic clamp. We showed that after ip injection of clozapine N-oxide, Gcg-Cre lean mice transduced with hM3Dq in the brainstem NTS downregulated basal endogenous glucose production and enhanced glucose tolerance following ip glucose tolerance test. Moreover, acute activation of PPG neurons NTS enhanced whole-body insulin sensitivity as indicated by increased glucose infusion rate as well as augmented insulin-suppression of endogenous glucose production and gluconeogenesis. In contrast, insulin-stimulation of glucose disposal was not altered significantly. We conclude that acute activation of PPG neurons in the brainstem reduces basal glucose production, enhances intraperitoneal glucose tolerance, and augments hepatic insulin sensitivity, suggesting an important physiological role of PPG neurons-mediated circuitry in promoting glycemic control and insulin sensitivity. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  12. Determining pancreatic β-cell compensation for changing insulin sensitivity using an oral glucose tolerance test

    DEFF Research Database (Denmark)

    Solomon, Thomas; Malin, Steven K; Karstoft, Kristian

    2014-01-01

    Plasma glucose, insulin, and C-peptide responses during an OGTT are informative for both research and clinical practice in type 2 diabetes. The aim of this study was to use such information to determine insulin sensitivity and insulin secretion so as to calculate an oral glucose disposition index...

  13. Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jiewu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China); Adeloju, Samuel B., E-mail: sam.adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China)

    2014-01-27

    Graphical abstract: -- Highlights: •Successfully synthesised highly-ordered gold nanowires array with an AAO template. •Fabricated an ultra-sensitive glucose nanobiosensor with the gold nanowires array. •Achieved sensitivity as high as 379.0 μA cm{sup −2} mM{sup −1} and detection limit as low as 50 nM. •Achieved excellent anti-interference with aid of Nafion membrane towards UA and AA. •Enabled successful detection and quantification of glucose in human blood serum. -- Abstract: A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO{sub x}) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA–BSA–GLA–GO{sub x} nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm{sup −2} mM{sup −1} for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5–6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples.

  14. Proximity to Delivery Alters Insulin Sensitivity and Glucose Metabolism in Pregnant Mice.

    Science.gov (United States)

    Musial, Barbara; Fernandez-Twinn, Denise S; Vaughan, Owen R; Ozanne, Susan E; Voshol, Peter; Sferruzzi-Perri, Amanda N; Fowden, Abigail L

    2016-04-01

    In late pregnancy, maternal insulin resistance occurs to support fetal growth, but little is known about insulin-glucose dynamics close to delivery. This study measured insulin sensitivity in mice in late pregnancy at day 16 (D16) and near term at D19. Nonpregnant (NP) and pregnant mice were assessed for metabolite and hormone concentrations, body composition by DEXA, tissue insulin signaling protein abundance by Western blotting, glucose tolerance and utilization, and insulin sensitivity using acute insulin administration and hyperinsulinemic-euglycemic clamps with [(3)H]glucose infusion. Whole-body insulin resistance occurred in D16 pregnant dams in association with basal hyperinsulinemia, insulin-resistant endogenous glucose production, and downregulation of several proteins in hepatic and skeletal muscle insulin signaling pathways relative to NP and D19 values. Insulin resistance was less pronounced at D19, with restoration of NP insulin concentrations, improved hepatic insulin sensitivity, and increased abundance of hepatic insulin signaling proteins. At D16, insulin resistance at whole-body, tissue, and molecular levels will favor fetal glucose acquisition, while improved D19 hepatic insulin sensitivity will conserve glucose for maternal use in anticipation of lactation. Tissue sensitivity to insulin, therefore, alters differentially with proximity to delivery in pregnant mice, with implications for human and other species. © 2016 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.

  15. A Highly Sensitive Electrochemical Glucose Sensor By Nickel-Epoxy Electrode With Non-Enzymatic Sensor

    Directory of Open Access Journals (Sweden)

    Riyanto Riyanto

    2016-03-01

    Full Text Available The preparation of new sensor for glucose was based on the fact that glucose can be determined by non-enzymatic glucose oxidase. The Ni metals (99.98% purity, 0.5 mm thick, Aldrich Chemical Company was used to prepare Ni-Epoxy electrode. The Ni-epoxy electrodes were prepared in square cut of 1 cm and 1 mm by length and wide respectively. The Ni metal electrodes were connected to silver wire with silver conducting paint prior covered with epoxy gum. The prepared of nickel-epoxy modified electrode showed outstanding electro catalytic activity toward the oxidation of glucose in alkaline solution. The result from this research are correlation of determination using Nickel-Epoxyelectrode for electroanalysis of glucose in NaOH was R2 = 0.9984. LOQ, LOD and recovery of the Nickel-Epoxy electrode towards glucose were found to be 4.4 μM, 1.48 μM and 98.19%, respectively. The Nickel-Epoxy wire based electrochemical glucose sensor demonstrates good sensitivity, wide linear range, outstanding detection limit, attractive selectivity, good reproducibility, high stability as well as prominent feasibility use of non-enzymatic sensor for monitoring glucose in human urine owing to its advantages of low cost, simple preparation and excellent properties for glucose detection.

  16. Systemic Glucose Level Changes with a Carbohydrate-Restricted and Higher Protein Diet Combined with Exercise

    Science.gov (United States)

    Bowden, Rodney G.; Lanning, Beth A.; Doyle, Eva I.; Slonaker, Becky; Johnston, Holly M.; Scanes, Georgene

    2007-01-01

    Objective: The authors' purpose in this study was to compare the effects of macronutrient intake on systemic glucose levels in previously sedentary participants who followed 1 of 4 diets that were either higher protein or high carbohydrate, while initiating an exercise program. Participants and Methods: The authors randomly assigned 94 sedentary…

  17. Higher Blood Glucose within the Normal Range Is Associated with More Severe Strokes

    DEFF Research Database (Denmark)

    Martin, Rolf J; Ratan, Rajiv R; Reding, Michael J

    2012-01-01

    Background. Higher fasting blood glucose (FBG) concentrations in the hyperglycemic range are associated with more severe strokes. Whether this association also extends into patients with FBG in the normoglycemic range is unclear. We studied the association of stroke severity and FBG in normoglyce...

  18. Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection.

    Science.gov (United States)

    Cui, Jiewu; Adeloju, Samuel B; Wu, Yucheng

    2014-01-27

    A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO(x)) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA-BSA-GLA-GO(x) nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm(-2) mM(-1) for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5-6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. PROXIMITY TO DELIVERY ALTERS INSULIN SENSITIVITY AND GLUCOSE METABOLISM IN PREGNANT MICE

    OpenAIRE

    Musial, Barbara; Fernandez-Twinn, Denise S.; Vaughan, Owen R.; Ozanne, Susan E.; Voshol, Peter; Sferruzzi-Perri, Amanda N.; Fowden, Abigail L.

    2016-01-01

    In late pregnancy, maternal insulin resistance occurs to support fetal growth but little is known about insulin-glucose dynamics close to delivery. This study measured insulin sensitivity in mice in late pregnancy, day (D) 16, and near term, D19, (term 20.5D). Non-pregnant (NP) and pregnant mice were assessed for metabolite and hormone concentrations, body composition by dual energy X-ray absorptiometry, tissue insulin signalling protein abundance by Western blotting, glucose tolerance and ut...

  20. Valsartan Improves β-Cell Function and Insulin Sensitivity in Subjects With Impaired Glucose Metabolism

    Science.gov (United States)

    van der Zijl, Nynke J.; Moors, Chantalle C.M.; Goossens, Gijs H.; Hermans, Marc M.H.; Blaak, Ellen E.; Diamant, Michaela

    2011-01-01

    OBJECTIVE Recently, the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research Trial demonstrated that treatment with the angiotensin receptor blocker (ARB) valsartan for 5 years resulted in a relative reduction of 14% in the incidence of type 2 diabetes in subjects with impaired glucose metabolism (IGM). We investigated whether improvements in β-cell function and/or insulin sensitivity underlie these preventive effects of the ARB valsartan in the onset of type 2 diabetes. RESEARCH DESIGN AND METHODS In this randomized controlled, double-blind, two-center study, the effects of 26 weeks of valsartan (320 mg daily; n = 40) or placebo (n = 39) on β-cell function and insulin sensitivity were assessed in subjects with impaired fasting glucose and/or impaired glucose tolerance, using a combined hyperinsulinemic-euglycemic and hyperglycemic clamp with subsequent arginine stimulation and a 2-h 75-g oral glucose tolerance test (OGTT). Treatment effects were analyzed using ANCOVA, adjusting for center, glucometabolic status, and sex. RESULTS Valsartan increased first-phase (P = 0.028) and second-phase (P = 0.002) glucose-stimulated insulin secretion compared with placebo, whereas the enhanced arginine-stimulated insulin secretion was comparable between groups (P = 0.25). In addition, valsartan increased the OGTT-derived insulinogenic index (representing first-phase insulin secretion after an oral glucose load; P = 0.027). Clamp-derived insulin sensitivity was significantly increased with valsartan compared with placebo (P = 0.049). Valsartan treatment significantly decreased systolic and diastolic blood pressure compared with placebo (P valsartan treatment increased glucose-stimulated insulin release and insulin sensitivity in normotensive subjects with IGM. These findings may partly explain the beneficial effects of valsartan in the reduced incidence of type 2 diabetes. PMID:21330640

  1. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

    OpenAIRE

    Xuemei Shi; Shaji Chacko; Feng Li; Depei Li; Douglas Burrin; Lawrence Chan; Xinfu Guan

    2017-01-01

    Objective: Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. Methods: We generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected...

  2. A flexible and highly sensitive nonenzymatic glucose sensor based on DVD-laser scribed graphene substrate.

    Science.gov (United States)

    Lin, Songyue; Feng, Wendou; Miao, Xiaofei; Zhang, Xiangxin; Chen, Sujing; Chen, Yuanqiang; Wang, Wei; Zhang, Yining

    2018-07-01

    Flexible and implantable glucose biosensors are emerging technologies for continuous monitoring of blood-glucose of diabetes. Developing a flexible conductive substrates with high active surface area is critical for advancing the technology. Here, we successfully fabricate a flexible and highly sensitive nonenzymatic glucose by using DVD-laser scribed graphene (LSG) as a flexible conductively substrate. Copper nanoparticles (Cu-NPs) are electrodeposited as the catalyst. The LSG/Cu-NPs sensor demonstrates excellent catalytic activity toward glucose oxidation and exhibits a linear glucose detection range from 1 μM to 4.54 mM with high sensitivity (1.518 mA mM -1 cm -2 ) and low limit of detection (0.35 μM). Moreover, the LSG/Cu-NPs sensor shows excellent reproducibility and long-term stability. It is also highly selective toward glucose oxidation under the presence of various interfering species. Excellent flexing stability is also demonstrated by the LSG/Cu-NPs sensor, which is capable of maintaining 83.9% of its initial current after being bent against a 4-mm diameter rod for 180 times. The LSG/Cu-NPs sensor shows great potential for practical application as a nonenzymatic glucose biosensor. Meanwhile, the LSG conductive substrate provides a platform for the developing next-generation flexible and potentially implantable bioelectronics and biosensors. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Quantum dots and ionic liquid-sensitized effect as an efficient and green catalyst for the sensitive determination of glucose.

    Science.gov (United States)

    Azizi, Seyed Naser; Chaichi, Mohammad Javad; Shakeri, Parmis; Bekhradnia, Ahmadreza

    2015-07-05

    A novel fluorescence (FL) method using water-soluble CdSe quantum dots (QDs) is proposed for the fluorometric determination of hydrogen peroxide and glucose. Water-soluble CdSe QDs were synthesized by using thioglycolic acid as stabilizer in aqueous solutions. The nanoparticles were structurally and optically characterized by X-ray powder diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), UV-Vis absorption spectroscopy, photoluminescence (PL) emission spectroscopy and transmission electron microscope (TEM). Ionic liquid-sensitized effect in aqueous solution was then investigated. In the presence of ionic liquid as catalyst, H2O2 was decomposed into radical that could quench the fluorescence of CdSe QDs more efficiently and rapidly. Then the oxidization of glucose by glucose oxidase was coupled with the fluorescence quenching of CdSe QDs by H2O2 producer with ionic liquid catalyst, which can be used to detect glucose. Therefore, a new FL analysis system was developed for the determination of glucose. Under the optimum conditions, there is a good linear relationship between the relative PL emission intensity and the concentration of glucose in the range of 5.0×10(-7)-1.0×10(-4) M of glucose with a correlation coefficient (R(2)) of 0.9973. The limit of detection of this system was found to be 1.0×10(-7) M. This method is not only simple, sensitive and low cost, but also reliable for practical applications. Copyright © 2015. Published by Elsevier B.V.

  4. P21-activated kinase 2 (PAK2) regulates glucose uptake and insulin sensitivity in neuronal cells.

    Science.gov (United States)

    Varshney, Pallavi; Dey, Chinmoy Sankar

    2016-07-05

    P21-activated kinases (PAKs) are recently reported as important players of insulin signaling and glucose homeostasis in tissues like muscle, pancreas and liver. However, their role in neuronal insulin signaling is still unknown. Present study reports the involvement of PAK2 in neuronal insulin signaling, glucose uptake and insulin resistance. Irrespective of insulin sensitivity, insulin stimulation decreased PAK2 activity. PAK2 downregulation displayed marked enhancement of GLUT4 translocation with increase in glucose uptake whereas PAK2 over-expression showed its reduction. Treatment with Akti-1/2 and wortmannin suggested that Akt and PI3K are mediators of insulin effect on PAK2 and glucose uptake. Rac1 inhibition demonstrated decreased PAK2 activity while inhibition of PP2A resulted in increased PAK2 activity, with corresponding changes in glucose uptake. Taken together, present study demonstrates an inhibitory role of insulin signaling (via PI3K-Akt) and PP2A on PAK2 activity and establishes PAK2 as a Rac1-dependent negative regulator of neuronal glucose uptake and insulin sensitivity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. High reproducibility and sensitivity of bifacial copper nanowire array for detection of glucose

    Directory of Open Access Journals (Sweden)

    Hanqing Zhang

    2017-06-01

    Full Text Available The ordered bifacial copper nanowire array (Cu BNWA was synthesized by a template assisted electrochemical deposition method. The morphology and structure of the as-prepared samples were investigated by field emission scanning electron microscope (FESEM and X-ray diffraction (XRD. The results show that the ordered Cu nanowire array with uniform geometrical dimensions covered both side of the Cu substrate. When used as the electrode for glucose detection, the minimum detectable concentration of glucose can be reached as low as 0.2 mM. Impressively, the sample still showed high sensitivity and stability for glucose detection after two months placement in ambient environment. These excellent performances of the Cu BNWA make it a promising non-enzyme glucose detection sensor for various applications.

  6. Platinum nanoparticles functionalized nitrogen doped graphene platform for sensitive electrochemical glucose biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhanjun, E-mail: zjyang@yzu.edu.cn; Cao, Yue; Li, Juan; Jian, Zhiqin; Zhang, Yongcai; Hu, Xiaoya

    2015-04-29

    Highlights: • An efficient PtNPs@NG nanocomposite was prepared for the immobilization of enzyme. • A novel electrochemical glucose biosensor was constructed based on this PtNPs@NG. • The proposed glucose biosensor showed high sensitivity and low detection limit. • The PtNPs@NG composite provided a promising platform for biosensing applications. - Abstract: In this work, we reported an efficient platinum nanoparticles functionalized nitrogen doped graphene (PtNPs@NG) nanocomposite for devising novel electrochemical glucose biosensor for the first time. The fabricated PtNPs@NG and biosensor were characterized using transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, static water contact angle, UV–vis spectroscopy, electrochemical impedance spectra and cyclic voltammetry, respectively. PtNPs@NG showed large surface area and excellent biocompatibility, and enhanced the direct electron transfer between enzyme molecules and electrode surface. The glucose oxidase (GOx) immobilized on PtNPs@NG nanocomposite retained its bioactivity, and exhibited a surface controlled, quasi-reversible and fast electron transfer process. The constructed glucose biosensor showed wide linear range from 0.005 to 1.1 mM with high sensitivity of 20.31 mA M{sup −1} cm{sup −2}. The detection limit was calculated to be 0.002 mM at signal-to-noise of 3, which showed 20-fold decrease in comparison with single NG-based electrochemical biosensor for glucose. The proposed glucose biosensor also demonstrated excellent selectivity, good reproducibility, acceptable stability, and could be successfully applied in the detection of glucose in serum samples at the applied potential of −0.33 V. This research provided a promising biosensing platform for the development of excellent electrochemical biosensors.

  7. Platinum nanoparticles functionalized nitrogen doped graphene platform for sensitive electrochemical glucose biosensing

    International Nuclear Information System (INIS)

    Yang, Zhanjun; Cao, Yue; Li, Juan; Jian, Zhiqin; Zhang, Yongcai; Hu, Xiaoya

    2015-01-01

    Highlights: • An efficient PtNPs@NG nanocomposite was prepared for the immobilization of enzyme. • A novel electrochemical glucose biosensor was constructed based on this PtNPs@NG. • The proposed glucose biosensor showed high sensitivity and low detection limit. • The PtNPs@NG composite provided a promising platform for biosensing applications. - Abstract: In this work, we reported an efficient platinum nanoparticles functionalized nitrogen doped graphene (PtNPs@NG) nanocomposite for devising novel electrochemical glucose biosensor for the first time. The fabricated PtNPs@NG and biosensor were characterized using transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, static water contact angle, UV–vis spectroscopy, electrochemical impedance spectra and cyclic voltammetry, respectively. PtNPs@NG showed large surface area and excellent biocompatibility, and enhanced the direct electron transfer between enzyme molecules and electrode surface. The glucose oxidase (GOx) immobilized on PtNPs@NG nanocomposite retained its bioactivity, and exhibited a surface controlled, quasi-reversible and fast electron transfer process. The constructed glucose biosensor showed wide linear range from 0.005 to 1.1 mM with high sensitivity of 20.31 mA M −1 cm −2 . The detection limit was calculated to be 0.002 mM at signal-to-noise of 3, which showed 20-fold decrease in comparison with single NG-based electrochemical biosensor for glucose. The proposed glucose biosensor also demonstrated excellent selectivity, good reproducibility, acceptable stability, and could be successfully applied in the detection of glucose in serum samples at the applied potential of −0.33 V. This research provided a promising biosensing platform for the development of excellent electrochemical biosensors

  8. Low whole-body insulin sensitivity in patients with ischaemic heart disease is associated with impaired myocardial glucose uptake predictive of poor outcome after revascularisation

    DEFF Research Database (Denmark)

    Kofoed, Klaus F; Carstensen, Steen; Hove, Jens D

    2002-01-01

    patients with ischaemic heart disease and impaired LV ejection fraction (EF) and age-matched healthy volunteers ( n = 30). As assessed by euglycaemic glucose-insulin clamp, 15 patients had a low and 14 a normal whole-body insulin sensitivity. Using positron emission tomography, patterns of fluorine-18......We tested the hypothesis that low whole-body insulin sensitivity in patients with ischaemic heart disease and impaired left ventricular (LV) function is associated with abnormalities of insulin-mediated myocardial glucose uptake affecting outcome after coronary bypass surgery (CABG). We studied 29......-normal myocardium was found to be higher in patients with normal whole-body insulin sensitivity ( P body insulin sensitivity more segments displayed a pattern of reduced glucose uptake in normoperfused myocardium (PET-reverse mismatch) ( P

  9. A simple method for measuring glucose utilization of insulin-sensitive tissues by using the brain as a reference

    International Nuclear Information System (INIS)

    Namba, Hiroki; Nakagawa, Keiichi; Iyo, Masaomi; Fukushi, Kiyoshi; Irie, Toshiaki

    1994-01-01

    A simple method, without measurement of the plasma input function, to obtain semiquantitative values of glucose utilization in tissues other than the brain with radioactive deoxyglucose is reported. The brain, in which glucose utilization is essentially insensitive to plasma glucose and insulin concentrations, was used as an internal reference. The effects of graded doses of oral glucose loading (0.5, 1 and 2 mg/g body weight) on insulin-sensitive tissues (heart, muscle and fat tissue) were studied in the rat. By using the brain-reference method, dose-dependent increases in glucose utilization were clearly shown in all the insulin-sensitive tissues examined. The method seems to be of value for measurement of glucose utilization using radioactive deoxyglucose and positron emission tomography in the heart or other insulin-sensitive tissues, especially during glucose loading. (orig.)

  10. The Proton-Activated Receptor GPR4 Modulates Glucose Homeostasis by Increasing Insulin Sensitivity

    Directory of Open Access Journals (Sweden)

    Luca Giudici

    2013-11-01

    Full Text Available Background: The proton-activated G protein-coupled receptor GPR4 is expressed in many tissues including white adipose tissue. GPR4 is activated by extracellular protons in the physiological pH range (i.e. pH 7.7 - 6.8 and is coupled to the production of cAMP. Methods: We examined mice lacking GPR4 and examined glucose tolerance and insulin sensitivity in young and aged mice as well as in mice fed with a high fat diet. Expression profiles of pro- and anti-inflammatory cytokines in white adipose tissue, liver and skeletal muscle was assessed. Results: Here we show that mice lacking GPR4 have an improved intraperitoneal glucose tolerance test and increased insulin sensitivity. Insulin levels were comparable but leptin levels were increased in GPR4 KO mice. Gpr4-/- showed altered expression of PPARα, IL-6, IL-10, TNFα, and TGF-1β in skeletal muscle, white adipose tissue, and liver. High fat diet abolished the differences in glucose tolerance and insulin sensitivity between Gpr4+/+ and Gpr4-/- mice. In contrast, in aged mice (12 months old, the positive effect of GPR4 deficiency on glucose tolerance and insulin sensitivity was maintained. Liver and adipose tissue showed no major differences in the mRNA expression of pro- and anti-inflammatory factors between aged mice of both genotypes. Conclusion: Thus, GPR4 deficiency improves glucose tolerance and insulin sensitivity. The effect may involve an altered balance between pro- and anti-inflammatory factors in insulin target tissues.

  11. Higher Fasting Plasma Glucose Levels, within the Normal Range, are Associated with Decreased Processing Speed in High Functioning Young Elderly

    OpenAIRE

    Raizes, Meytal; Elkana, Odelia; Franko, Motty; Springer, Ramit Ravona; Segev, Shlomo; Beeri, Michal Schnaider

    2016-01-01

    We explored the association of plasma glucose levels within the normal range with processing speed in high functioning young elderly, free of type 2 diabetes mellitus (T2DM). A sample of 41 participants (mean age = 64.7, SD = 10; glucose 94.5 mg/dL, SD = 9.3), were examined with a computerized cognitive battery. Hierarchical linear regression analysis showed that higher plasma glucose levels, albeit within the normal range (

  12. Rapid, Sensitive, and Reusable Detection of Glucose by a Robust Radiofrequency Integrated Passive Device Biosensor Chip

    Science.gov (United States)

    Kim, Nam-Young; Adhikari, Kishor Kumar; Dhakal, Rajendra; Chuluunbaatar, Zorigt; Wang, Cong; Kim, Eun-Soo

    2015-01-01

    Tremendous demands for sensitive and reliable label-free biosensors have stimulated intensive research into developing miniaturized radiofrequency resonators for a wide range of biomedical applications. Here, we report the development of a robust, reusable radiofrequency resonator based integrated passive device biosensor chip fabricated on a gallium arsenide substrate for the detection of glucose in water-glucose solutions and sera. As a result of the highly concentrated electromagnetic energy between the two divisions of an intertwined spiral inductor coupled with an interdigital capacitor, the proposed glucose biosensor chip exhibits linear detection ranges with high sensitivity at center frequency. This biosensor, which has a sensitivity of up to 199 MHz/mgmL−1 and a short response time of less than 2 sec, exhibited an ultralow detection limit of 0.033 μM and a reproducibility of 0.61% relative standard deviation. In addition, the quantities derived from the measured S-parameters, such as the propagation constant (γ), impedance (Z), resistance (R), inductance (L), conductance (G) and capacitance (C), enabled the effective multi-dimensional detection of glucose. PMID:25588958

  13. Effects of High Fat Diet and Physical Exercise on Glucose Tolelance and Insulin Sensitivity in Rats

    OpenAIRE

    福田,哲也

    1987-01-01

    To investigate the interrelationships between the westernized diet and physical exercise as they affect the development of non-insulin-dependent diabetes mellitus (NIDDM), adiposity, glucose tolerance and insulin response to an intraperitoneal glucose load (1.5g/kg bw) and insulin sensitivity to exogenous insulin (0.2U/kg bw) were studied in spontaneously exercised and sedentary rats fed either a high fat diet (40% fat, modern western type) or a low fat diet (10% fat, traditional Japanese typ...

  14. High sensitivity C-reactive protein and its relationship with impaired glucose regulation in lean patients with polycystic ovary syndrome.

    Science.gov (United States)

    Kim, Ji Won; Han, Ji Eun; Kim, You Shin; Won, Hyung Jae; Yoon, Tae Ki; Lee, Woo Sik

    2012-04-01

    The polycystic ovary syndrome (PCOS) is the most common endocrine-metabolic disorder, also associated with the metabolic syndrome. Serum high sensitivity C-reactive protein (hs-CRP), a marker of low-grade chronic inflammation is a potent predictor of cardiovascular events, closely linked to metabolic syndrome features and higher in patients with PCOS. However, hs-CRP in lean patients with PCOS has not been fully evaluated and few data are available. We aimed to investigate the relation between glucose intolerance and hs-CRP levels in lean patients with PCOS, and to evaluate the possible relationship between hs-CRP and PCOS by evaluating PCOS-related metabolic abnormalities in Korean women. We consecutively recruited 115 lean (BMI PCOS and 103 lean healthy controls. The PCOS group was divided two groups: impaired glucose regulation (IGR) and normal glucose tolerance group (NGT). In lean patients with PCOS, hs-CRP level was higher in the IGR group than in the NGT group (0.60 ± 1.37 versus 0.18 ± 0.46, p(Bonf) = 0.023) and other metabolic risk factors were also higher in the IGR group than in the NGT group. And there were close relationships between hs-CRP level and metabolic risk factor, such as 2 h postprandial insulin level in the lean patients with PCOS.

  15. Glucose metabolism-weighted imaging with chemical exchange-sensitive MRI of 2-deoxyglucose (2DG) in brain: Sensitivity and biological sources.

    Science.gov (United States)

    Jin, Tao; Mehrens, Hunter; Wang, Ping; Kim, Seong-Gi

    2016-12-01

    Recent proof-of-principle studies have demonstrated the feasibility of measuring the uptake and metabolism of non-labeled 2-deoxy-D-glucose (2DG) by a chemical exchange-sensitive spin-lock (CESL) MRI approach. In order to gain better understanding of this new approach, we performed dynamic in vivo CESL MRI on healthy rat brains with an intravenous injection of 2DG under various conditions at 9.4T. For three 2DG doses of 0.25, 0.5 and 1g/kg, we found that 2DG-CESL signals increased linearly with injection dose at the initial (40min) suggesting time-dependent differential weightings of 2DG transport and metabolism. Remaining 2DG-CESL studies were performed with 0.25g/kg 2DG. Since a higher isoflurane level reduces glucose metabolism and increases blood flow, 2DG-CESL was measured under 0.5%, 1.5% and 2.2% isoflurane. The 2DG-CESL signal was reduced at higher isoflurane levels correlating well with the 2DG phosphorylation in the intracellular space. To detect regional heterogeneities of glucose metabolism, 2DG-CESL with 0.33×0.33×1.50mm 3 resolution was obtained, which indeed showed a higher response in the cortex compared to the corpus callosum. Lastly, unlike CESL MRI with the injection of non-transportable mannitol, the 2DG-CESL response decreased with an increased spin-lock pulse power confirming that 2DG-CESL is dominated by chemical exchange processes in the extravascular space. Taken together, our results showed that 2DG-CESL MRI signals mainly indicate glucose transport and metabolism and may be a useful biomarker for metabolic studies of normal and diseased brains. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Maternal insulin sensitivity is associated with oral glucose-induced changes in fetal brain activity.

    Science.gov (United States)

    Linder, Katarzyna; Schleger, Franziska; Ketterer, Caroline; Fritsche, Louise; Kiefer-Schmidt, Isabelle; Hennige, Anita; Häring, Hans-Ulrich; Preissl, Hubert; Fritsche, Andreas

    2014-06-01

    Fetal programming plays an important role in the pathogenesis of type 2 diabetes. The aim of the present study was to investigate whether maternal metabolic changes during OGTT influence fetal brain activity. Thirteen healthy pregnant women underwent an OGTT (75 g). Insulin sensitivity was determined by glucose and insulin measurements at 0, 60 and 120 min. At each time point, fetal auditory evoked fields were recorded with a fetal magnetoencephalographic device and response latencies were determined. Maternal insulin increased from a fasting level of 67 ± 25 pmol/l (mean ± SD) to 918 ± 492 pmol/l 60 min after glucose ingestion and glucose levels increased from 4.4 ± 0.3 to 7.4 ± 1.1 mmol/l. Over the same time period, fetal response latencies decreased from 297 ± 99 to 235 ± 84 ms (p = 0.01) and then remained stable until 120 min (235 ± 84 vs 251 ± 91 ms, p = 0.39). There was a negative correlation between maternal insulin sensitivity and fetal response latencies 60 min after glucose ingestion (r = 0.68, p = 0.02). After a median split of the group based on maternal insulin sensitivity, fetuses of insulin-resistant mothers showed a slower response to auditory stimuli (283 ± 79 ms) than those of insulin-sensitive mothers (178 ± 46 ms, p = 0.03). Lower maternal insulin sensitivity is associated with slower fetal brain responses. These findings provide the first evidence of a direct effect of maternal metabolism on fetal brain activity and suggest that central insulin resistance may be programmed during fetal development.

  17. Effects of Higher Dietary Protein and Fiber Intakes at Breakfast on Postprandial Glucose, Insulin, and 24-h Interstitial Glucose in Overweight Adults.

    Science.gov (United States)

    Amankwaah, Akua F; Sayer, R Drew; Wright, Amy J; Chen, Ningning; McCrory, Megan A; Campbell, Wayne W

    2017-04-02

    Dietary protein and fiber independently influence insulin-mediated glucose control. However, potential additive effects are not well-known. Men and women ( n = 20; age: 26 ± 5 years; body mass index: 26.1 ± 0.2 kg/m²; mean ± standard deviation) consumed normal protein and fiber (NPNF; NP = 12.5 g, NF = 2 g), normal protein and high fiber (NPHF; NP = 12.5 g, HF = 8 g), high protein and normal fiber (HPNF; HP = 25 g, NF = 2 g), or high protein and fiber (HPHF; HP = 25 g, HF = 8 g) breakfast treatments during four 2-week interventions in a randomized crossover fashion. On the last day of each intervention, meal tolerance tests were completed to assess postprandial (every 60 min for 240 min) serum glucose and insulin concentrations. Continuous glucose monitoring was used to measure 24-h interstitial glucose during five days of the second week of each intervention. Repeated-measures ANOVA was applied for data analyses. The HPHF treatment did not affect postprandial glucose and insulin responses or 24-h glucose total area under the curve (AUC). Higher fiber intake reduced 240-min insulin AUC. Doubling the amount of protein from 12.5 g to 25 g/meal and quadrupling fiber from 2 to 8 g/meal at breakfast was not an effective strategy for modulating insulin-mediated glucose responses in these young, overweight adults.

  18. Response to dexamethasone is glucose-sensitive in multiple myeloma cell lines

    Directory of Open Access Journals (Sweden)

    Turturro Francesco

    2011-09-01

    Full Text Available Abstract Background Hyperglycemia is among the major side effects of dexamethasone (DEX. Glucose or glucocorticoid (GC regulates the expression of thioredoxin-interacting protein (TXNIP that controls the production of reactive oxygen species (ROS through the modulation of thioredoxin (TRX activity. Methods Multiple myeloma (MM cells were grown in 5 or 20 mM/L glucose with or without 25 μM DEX. Semiquantitative reverse transcription-PCR (RT-PCR was used to assess TXNIP RNA expression in response to glucose and DEX. ROS were detected by 5-6-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA. TRX activity was assayed by the insulin disulfide-reducing assay. Proliferation was evaluated using CellTiter96 reagent with 490-nm absorbtion and used to calculate the DEX IC50 in 20 mM/L glucose using the Chou's dose effect equation. Results TXNIP RNA level responded to glucose or DEX with the same order of magnitude ARH77 > NCIH929 > U266B1 in these cells. MC/CAR cells were resistant to the regulation. ROS level increased concurrently with reduced TRX activity. Surprisingly glucose increased TRX activity in MC/CAR cells keeping ROS level low. DEX and glucose were lacking the expected additive effect on TXNIP RNA regulation when used concurrently in sensitive cells. ROS level was significantly lower when DEX was used in conditions of hyperglycemia in ARH77/NCIH9292 cells but not in U266B1 cells. Dex-IC50 increased 10-fold when the dose response effect of DEX was evaluated with glucose in ARH && and MC/Car cells Conclusions Our study shows for the first time that glucose or DEX regulates important components of ROS production through TXNIP modulation or direct interference with TRX activity in MM cells. We show that glucose modulates the activity of DEX through ROS regualtion in MM cells. A better understanding of these pathways may help in improving the efficacy and reducing the toxicity of DEX, a drug still highly used in the treatment of

  19. Fabrication of Glucose-Sensitive Layer-by-Layer Films for Potential Controlled Insulin Release Applications

    Directory of Open Access Journals (Sweden)

    Talusan Timothy Jemuel E.

    2015-01-01

    Full Text Available Self-regulated drug delivery systems (DDS are potential alternative to the conventional method of introducing insulin to the body due to their controlled drug release mechanism. In this study, Layer-by-Layer technique was utlized to manufacture drug loaded, pH responsive thin films. Insulin was alternated with pH-sensitive, [2-(dimethyl amino ethyl aminoacrylate] (PDMAEMA and topped of with polymer/glucose oxidase (GOD layers. Similarly, films using a different polymer, namely Poly(Acrylic Acid (PAA were also fabricated. Exposure of the films to glucose solutions resulted to the production of gluconic acid causing a polymer conformation change due to protonation, thus releasing the embedded insulin. The insulin release was monitored by subjecting the dipping glucose solutions to Bradford Assay. Films exhibited a reversal in drug release profile in the presence of glucose as compared to without glucose. PAA films were also found out to release more insulin compared to that of the PDMAEMA films.The difference in the profile of the two films were due to different polymer-GOD interactions, since both films exhibited almost identical profiles when embedded with Poly(sodium 4-styrenesulfonate (PSS instead of GOD.

  20. Sensitive detection of maltose and glucose based on dual enzyme-displayed bacteria electrochemical biosensor.

    Science.gov (United States)

    Liu, Aihua; Lang, Qiaolin; Liang, Bo; Shi, Jianguo

    2017-01-15

    Glucoamylase-displayed bacteria (GA-bacteria) and glucose dehydrogenase-displayed bacteria (GDH-bacteria) were co-immobilized on multi-walled carbon nanotubes (MWNTs) modified glassy carbon electrode (GCE) to construct GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor. The biosensor was developed by optimizing the loading amount and the ratio of GA-bacteria to GDH-bacteria. The as-prepared biosensor exhibited a wide dynamic range of 0.2-10mM and a low detection limit of 0.1mM maltose (S/N=3). The biosensor also had a linear response to glucose in the range of 0.1-2.0mM and a low detection limit of 0.04mM glucose (S/N=3). Interestingly, at the same concentration, glucose was 3.75-fold sensitive than that of maltose at the proposed biosensor. No interferences were observed for other possible mono- and disaccharides. The biosensor also demonstrated good long-term storage stability and repeatability. Further, using both GDH-bacteria/MWNTs/GCE biosensor and GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor, glucose and maltose in real samples can be detected. Therefore, the proposed biosensor is capable of monitoring the food manufacturing and fermentation process. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Highly sensitive glucose sensor based on monodisperse palladium nickel/activated carbon nanocomposites.

    Science.gov (United States)

    Koskun, Yağmur; Şavk, Aysun; Şen, Betül; Şen, Fatih

    2018-06-20

    Glucose enzyme biosensors have been used for a variety of applications such as medical diagnosis, bioprocess engineering, beverage industry and environmental scanning etc. and there is still a growing interest in glucose sensors. For this purpose, addressed herein, as a novel glucose sensor, highly sensitive activated carbon (AC) decorated monodisperse nickel and palladium alloy nanocomposites modified glassy carbon electrode (Ni-Pd@AC/GCE NCs) have been synthesized by in-situ reduction technique. Raman Spectroscopy (RS), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), cyclic voltammetry (CV) and chronoamperometry (CA) were used for the characterization of the prepared non-enzymatic glucose sensor. The characteristic sensor properties of the Ni-Pd@AC/GCE electrode were compared with Ni-Pd NCs/GCE, Ni@AC/GCE and Pd@AC/GCE and the results demonstrate that the AC is very effective in the enhancement of the electrocatalytic properties of sensor. In addition, the Ni-Pd@AC/GCE nanocomposites showed a very low detection limit of 0.014 μM, a wide linear range of 0.01 mM-1 mM and a very high sensitivity of 90 mA mM -1  cm -2 . Furthermore, the recommended sensor offer the various advantageous such as facile preparation, fast response time, high selectivity and sensitivity. Lastly, monodisperse Ni-Pd@AC/GCE was utilized to detect glucose in real sample species. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Differentiation of the insulin-sensitive glucose transporter in 3T3-L1 adipocytes

    International Nuclear Information System (INIS)

    Frost, S.C.; Baly, D.L.; Cushman, S.W.; Lane, M.D.; Simpson, I.A.

    1986-01-01

    3T3-L1 fibroblasts differentiate in culture to resemble adipocytes both morphologically and biochemically. Insulin-sensitive glucose transport, as measured by 2-deoxy-[1- 14 C]- glucose uptake in the undifferentiated cell is small (2X). In contrast, the rate of glucose transport in fully differentiated cells is elevated 15-fold over basal in the presence of insulin. To determine if this is due to an increase in the number of transporters/cell or accessibility to the transporters, the number of transporters was measured in subcellular fractions over differentiation using a 3 H-cytochalasin B binding assay. The increase in the rate of insulin-sensitive glucose transport directly parallels an increase in the number of transporters which reside in an insulin-responsive intracellular compartment. This observation was confirmed by identifying the transporters by immunoblotting using an antibody generated against the human erythrocyte transporter. The molecular weight of this transporter increases over differentiation from a single band of 40kDa to a heterogeneous triplet of 40, 44 and 48kDa. These data suggest that the transporter undergoes differential processing and that the functional, insulin-responsive transporter may be different from the insulin-insensitive (basal) transporter

  3. Rare Sugar Syrup Containing d-Allulose but Not High-Fructose Corn Syrup Maintains Glucose Tolerance and Insulin Sensitivity Partly via Hepatic Glucokinase Translocation in Wistar Rats.

    Science.gov (United States)

    Shintani, Tomoya; Yamada, Takako; Hayashi, Noriko; Iida, Tetsuo; Nagata, Yasuo; Ozaki, Nobuaki; Toyoda, Yukiyasu

    2017-04-05

    Ingestion of high-fructose corn syrup (HFCS) is associated with the risk of both diabetes and obesity. Rare sugar syrup (RSS) has been developed by alkaline isomerization of HFCS and has anti-obesity and anti-diabetic effects. However, the influence of RSS on glucose metabolism has not been explored. We investigated whether long-term administration of RSS maintains glucose tolerance and whether the underlying mechanism involves hepatic glucokinase translocation. Wistar rats were administered water, RSS, or HFCS in drinking water for 10 weeks and then evaluated for glucose tolerance, insulin tolerance, liver glycogen content, and subcellular distribution of liver glucokinase. RSS significantly suppressed body weight gain and abdominal fat mass (p glucose tolerance test revealed significantly higher blood glucose levels in the HFCS group compared to the water group, whereas the RSS group had significantly lower blood glucose levels from 90 to 180 min (p water group (p glucose loading, the nuclear export of glucokinase was significantly increased in the RSS group compared to the water group. These results imply that RSS maintains glucose tolerance and insulin sensitivity, at least partly, by enhancing nuclear export of hepatic glucokinase.

  4. Glucose-Responsive Insulin Delivery by Microneedle-Array Patches Loaded with Hypoxia-Sensitive Vesicles.

    Science.gov (United States)

    Yu, Jicheng; Zhang, Yuqi; Gu, Zhen

    2017-01-01

    In this chapter, we describe the preparation of glucose-responsive vesicles (GRVs) and the fabrication of GRV-loaded microneedle-array patches for insulin delivery. The GRVs were formed of hypoxia-sensitive hyaluronic acid (HS-HA), the synthesis of which is presented in detail. We also describe the procedure to evaluate the in vivo efficacy of this smart patch in a mouse model of chemically induced type 1 diabetes through transcutaneous administration.

  5. Protein-bound NAD(P)H Lifetime is Sensitive to Multiple Fates of Glucose Carbon.

    Science.gov (United States)

    Sharick, Joe T; Favreau, Peter F; Gillette, Amani A; Sdao, Sophia M; Merrins, Matthew J; Skala, Melissa C

    2018-04-03

    While NAD(P)H fluorescence lifetime imaging (FLIM) can detect changes in flux through the TCA cycle and electron transport chain (ETC), it remains unclear whether NAD(P)H FLIM is sensitive to other potential fates of glucose. Glucose carbon can be diverted from mitochondria by the pentose phosphate pathway (via glucose 6-phosphate dehydrogenase, G6PDH), lactate production (via lactate dehydrogenase, LDH), and rejection of carbon from the TCA cycle (via pyruvate dehydrogenase kinase, PDK), all of which can be upregulated in cancer cells. Here, we demonstrate that multiphoton NAD(P)H FLIM can be used to quantify the relative concentrations of recombinant LDH and malate dehydrogenase (MDH) in solution. In multiple epithelial cell lines, NAD(P)H FLIM was also sensitive to inhibition of LDH and PDK, as well as the directionality of LDH in cells forced to use pyruvate versus lactate as fuel sources. Among the parameters measurable by FLIM, only the lifetime of protein-bound NAD(P)H (τ 2 ) was sensitive to these changes, in contrast to the optical redox ratio, mean NAD(P)H lifetime, free NAD(P)H lifetime, or the relative amount of free and protein-bound NAD(P)H. NAD(P)H τ 2 offers the ability to non-invasively quantify diversions of carbon away from the TCA cycle/ETC, which may support mechanisms of drug resistance.

  6. Insulin-sensitive phospholipid signaling systems and glucose transport. Update II.

    Science.gov (United States)

    Farese, R V

    2001-04-01

    Insulin provokes rapid changes in phospholipid metabolism and thereby generates biologically active lipids that serve as intracellular signaling factors that regulate glucose transport and glycogen synthesis. These changes include: (i) activation of phosphatidylinositol 3-kinase (PI3K) and production of PIP3; (ii) PIP3-dependent activation of atypical protein kinase Cs (PKCs); (iii) PIP3-dependent activation of PKB; (iv) PI3K-dependent activation of phospholipase D and hydrolysis of phosphatidylcholine with subsequent increases in phosphatidic acid (PA) and diacylglycerol (DAG); (v) PI3K-independent activation of glycerol-3-phosphate acylytansferase and increases in de novo synthesis of PA and DAG; and (vi) activation of DAG-sensitive PKCs. Recent findings suggest that atypical PKCs and PKB serve as important positive regulators of insulin-stimulated glucose metabolism, whereas mechanisms that result in the activation of DAG-sensitive PKCs serve mainly as negative regulators of insulin signaling through PI3K. Atypical PKCs and PKB are rapidly activated by insulin in adipocytes, liver, skeletal muscles, and other cell types by a mechanism requiring PI3K and its downstream effector, 3-phosphoinositide-dependent protein kinase-1 (PDK-1), which, in conjunction with PIP3, phosphorylates critical threonine residues in the activation loops of atypical PKCs and PKB. PIP3 also promotes increases in autophosphorylation and allosteric activation of atypical PKCs. Atypical PKCs and perhaps PKB appear to be required for insulin-induced translocation of the GLUT 4 glucose transporter to the plasma membrane and subsequent glucose transport. PKB also appears to be the major regulator of glycogen synthase. Together, atypical PKCs and PKB serve as a potent, integrated PI3K/PDK-1-directed signaling system that is used by insulin to regulate glucose metabolism.

  7. A sensitive glucose biosensor based on Ag@C core–shell matrix

    International Nuclear Information System (INIS)

    Zhou, Xuan; Dai, Xingxin; Li, Jianguo; Long, Yumei; Li, Weifeng; Tu, Yifeng

    2015-01-01

    Nano-Ag particles were coated with colloidal carbon (Ag@C) to improve its biocompatibility and chemical stability for the preparation of biosensor. The core–shell structure was evidenced by transmission electron microscope (TEM) and the Fourier transfer infrared (FTIR) spectra revealed that the carbon shell is rich of function groups such as − OH and − COOH. The as-prepared Ag@C core–shell structure can offer favorable microenvironment for immobilizing glucose oxidase and the direct electrochemistry process of glucose oxidase (GOD) at Ag@C modified glassy carbon electrode (GCE) was realized. The modified electrode exhibited good response to glucose. Under optimum experimental conditions the biosensor linearly responded to glucose concentration in the range of 0.05–2.5 mM, with a detection limit of 0.02 mM (S/N = 3). The apparent Michaelis–Menten constant (K M app ) of the biosensor is calculated to be 1.7 mM, suggesting high enzymatic activity and affinity toward glucose. In addition, the GOD-Ag@C/Nafion/GCE shows good reproducibility and long-term stability. These results suggested that core–shell structured Ag@C is an ideal matrix for the immobilization of the redox enzymes and further the construction of the sensitive enzyme biosensor. - Highlights: • Enhanced direct electrochemistry of GOD was achieved at Ag@C modified electrode. • A novel glucose biosensor based on Ag@C core–shell structure was developed. • The designed GOD-Ag@C/Nafion/GCE biosensor showed favorable analysis properties. • The biosensor is easy to prepare and can be applied for real sample assay

  8. A sensitive glucose biosensor based on Ag@C core–shell matrix

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xuan; Dai, Xingxin; Li, Jianguo [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); Long, Yumei, E-mail: yumeilong@suda.edu.cn [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou (China); Li, Weifeng, E-mail: liweifeng@suda.edu.cn [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); Tu, Yifeng [College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou (China)

    2015-04-01

    Nano-Ag particles were coated with colloidal carbon (Ag@C) to improve its biocompatibility and chemical stability for the preparation of biosensor. The core–shell structure was evidenced by transmission electron microscope (TEM) and the Fourier transfer infrared (FTIR) spectra revealed that the carbon shell is rich of function groups such as − OH and − COOH. The as-prepared Ag@C core–shell structure can offer favorable microenvironment for immobilizing glucose oxidase and the direct electrochemistry process of glucose oxidase (GOD) at Ag@C modified glassy carbon electrode (GCE) was realized. The modified electrode exhibited good response to glucose. Under optimum experimental conditions the biosensor linearly responded to glucose concentration in the range of 0.05–2.5 mM, with a detection limit of 0.02 mM (S/N = 3). The apparent Michaelis–Menten constant (K{sub M}{sup app}) of the biosensor is calculated to be 1.7 mM, suggesting high enzymatic activity and affinity toward glucose. In addition, the GOD-Ag@C/Nafion/GCE shows good reproducibility and long-term stability. These results suggested that core–shell structured Ag@C is an ideal matrix for the immobilization of the redox enzymes and further the construction of the sensitive enzyme biosensor. - Highlights: • Enhanced direct electrochemistry of GOD was achieved at Ag@C modified electrode. • A novel glucose biosensor based on Ag@C core–shell structure was developed. • The designed GOD-Ag@C/Nafion/GCE biosensor showed favorable analysis properties. • The biosensor is easy to prepare and can be applied for real sample assay.

  9. Deletion of interleukin 1 receptor-associated kinase 1 (Irak1) improves glucose tolerance primarily by increasing insulin sensitivity in skeletal muscle.

    Science.gov (United States)

    Sun, Xiao-Jian; Kim, Soohyun Park; Zhang, Dongming; Sun, Helen; Cao, Qi; Lu, Xin; Ying, Zhekang; Li, Liwu; Henry, Robert R; Ciaraldi, Theodore P; Taylor, Simeon I; Quon, Michael J

    2017-07-21

    Chronic inflammation may contribute to insulin resistance via molecular cross-talk between pathways for pro-inflammatory and insulin signaling. Interleukin 1 receptor-associated kinase 1 (IRAK-1) mediates pro-inflammatory signaling via IL-1 receptor/Toll-like receptors, which may contribute to insulin resistance, but this hypothesis is untested. Here, we used male Irak1 null (k/o) mice to investigate the metabolic role of IRAK-1. C57BL/6 wild-type (WT) and k/o mice had comparable body weights on low-fat and high-fat diets (LFD and HFD, respectively). After 12 weeks on LFD (but not HFD), k/o mice ( versus WT) had substantially improved glucose tolerance (assessed by the intraperitoneal glucose tolerance test (IPGTT)). As assessed with the hyperinsulinemic euglycemic glucose clamp technique, insulin sensitivity was 30% higher in the Irak1 k/o mice on chow diet, but the Irak1 deletion did not affect IPGTT outcomes in mice on HFD, suggesting that the deletion did not overcome the impact of obesity on glucose tolerance. Moreover, insulin-stimulated glucose-disposal rates were higher in the k/o mice, but we detected no significant difference in hepatic glucose production rates (± insulin infusion). Positron emission/computed tomography scans indicated higher insulin-stimulated glucose uptake in muscle, but not liver, in Irak1 k/o mice in vivo Moreover, insulin-stimulated phosphorylation of Akt was higher in muscle, but not in liver, from Irak1 k/o mice ex vivo In conclusion, Irak1 deletion improved muscle insulin sensitivity, with the effect being most apparent in LFD mice. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Leptin rapidly improves glucose homeostasis in obese mice by increasing hypothalamic insulin sensitivity.

    Science.gov (United States)

    Koch, Christiane; Augustine, Rachael A; Steger, Juliane; Ganjam, Goutham K; Benzler, Jonas; Pracht, Corinna; Lowe, Chrishanthi; Schwartz, Michael W; Shepherd, Peter R; Anderson, Greg M; Grattan, David R; Tups, Alexander

    2010-12-01

    Obesity is associated with resistance to the actions of both leptin and insulin via mechanisms that remain incompletely understood. To investigate whether leptin resistance per se contributes to insulin resistance and impaired glucose homeostasis, we investigated the effect of acute leptin administration on glucose homeostasis in normal as well as leptin- or leptin receptor-deficient mice. In hyperglycemic, leptin-deficient Lep(ob/ob) mice, leptin acutely and potently improved glucose metabolism, before any change of body fat mass, via a mechanism involving the p110α and β isoforms of phosphatidylinositol-3-kinase (PI3K). Unlike insulin, however, the anti-diabetic effect of leptin occurred independently of phospho-AKT, a major downstream target of PI3K, and instead involved enhanced sensitivity of the hypothalamus to insulin action upstream of PI3K, through modulation of IRS1 (insulin receptor substrate 1) phosphorylation. These data suggest that leptin resistance, as occurs in obesity, reduces the hypothalamic response to insulin and thereby impairs peripheral glucose homeostasis, contributing to the development of type 2 diabetes.

  11. A comparison between the minimal model and the glucose clamp in the assessment of insulin sensitivity across the spectrum of glucose tolerance. Insulin Resistance Atherosclerosis Study.

    Science.gov (United States)

    Saad, M F; Anderson, R L; Laws, A; Watanabe, R M; Kades, W W; Chen, Y D; Sands, R E; Pei, D; Savage, P J; Bergman, R N

    1994-09-01

    An insulin-modified frequently sampled intravenous glucose tolerance test (FSIGTT) with minimal model analysis was compared with the glucose clamp in 11 subjects with normal glucose tolerance (NGT), 20 with impaired glucose tolerance (IGT), and 24 with non-insulin-dependent diabetes mellitus (NIDDM). The insulin sensitivity index (SI) was calculated from FSIGTT using 22- and 12-sample protocols (SI(22) and SI(12), respectively). Insulin sensitivity from the clamp was expressed as SI(clamp) and SIP(clamp). Minimal model parameters were similar when calculated with SI(22) and SI(12). SI could not be distinguished from 0 in approximately 50% of diabetic patients with either protocol. SI(22) correlated significantly with SI(clamp) in the whole group (r = 0.62), and in the NGT (r = 0.53), IGT (r = 0.48), and NIDDM (r = 0.41) groups (P SIP(clamp) were expressed in the same units, SI(22) was 66 +/- 5% (mean +/- SE) and 50 +/- 8% lower than SI(clamp) and SIP(clamp), respectively. Thus, minimal model analysis of the insulin-modified FSIGTT provides estimates of insulin sensitivity that correlate significantly with those from the glucose clamp. The correlation was weaker, however, in NIDDM. The insulin-modified FSIGTT can be used as a simple test for assessment of insulin sensitivity in population studies involving nondiabetic subjects. Additional studies are needed before using this test routinely in patients with NIDDM.

  12. Glut2-dependent glucose-sensing controls thermoregulation by enhancing the leptin sensitivity of NPY and POMC neurons.

    Science.gov (United States)

    Mounien, Lourdes; Marty, Nell; Tarussio, David; Metref, Salima; Genoux, David; Preitner, Frédéric; Foretz, Marc; Thorens, Bernard

    2010-06-01

    The physiological contribution of glucose in thermoregulation is not completely established nor whether this control may involve a regulation of the melanocortin pathway. Here, we assessed thermoregulation and leptin sensitivity of hypothalamic arcuate neurons in mice with inactivation of glucose transporter type 2 (Glut2)-dependent glucose sensing. Mice with inactivation of Glut2-dependent glucose sensors are cold intolerant and show increased susceptibility to food deprivation-induced torpor and abnormal hypothermic response to intracerebroventricular administration of 2-deoxy-d-glucose compared to control mice. This is associated with a defect in regulated expression of brown adipose tissue uncoupling protein I and iodothyronine deiodinase II and with a decreased leptin sensitivity of neuropeptide Y (NPY) and proopiomelanocortin (POMC) neurons, as observed during the unfed-to-refed transition or following i.p. leptin injection. Sites of central Glut-2 expression were identified by a genetic tagging approach and revealed that glucose-sensitive neurons were present in the lateral hypothalamus, the dorsal vagal complex, and the basal medulla but not in the arcuate nucleus. NPY and POMC neurons were, however, connected to nerve terminals from Glut2-expressing neurons. Thus, our data suggest that glucose controls thermoregulation and the leptin sensitivity of NPY and POMC neurons through activation of Glut2-dependent glucose-sensing neurons located outside of the arcuate nucleus.

  13. On-chip highly sensitive saliva glucose sensing using multilayer films composed of single-walled carbon nanotubes, gold nanoparticles, and glucose oxidase

    Directory of Open Access Journals (Sweden)

    Wenjun Zhang

    2015-06-01

    Full Text Available It is very important for human health to rapidly and accurately detect glucose levels in biological environments, especially for diabetes mellitus. We proposed a simple, highly sensitive, accurate, convenient, low-cost, and disposable glucose biosensor on a single chip. A working (sensor electrode, a counter electrode, and a reference electrode are integrated on a single chip through micro-fabrication. The working electrode is functionalized through a layer-by-layer (LBL assembly of single-walled carbon nanotubes (SWNTs and multilayer films composed of chitosan (CS, gold nanoparticles (GNp, and glucose oxidase (GOx to obtain high sensitivity and accuracy. The glucose sensor has following features: (1 direct electron transfer between GOx and the electrode surface; (2 on-a-chip; (3 glucose detection down to 0.1 mg/dL (5.6 μM; (4 good sensing linearity over 0.017–0.81 mM; (5 high sensitivity (61.4 μA/mM-cm2 with a small reactive area (8 mm2; (6 fast response; (7 high reproducibility and repeatability; (8 reliable and accurate saliva glucose detection. Thus, this disposable biosensor will be an alternative for real time tracking of glucose levels from body fluids, e.g. saliva, in a noninvasive, pain-free, accurate, and continuous way. In addition to being used as a disposable glucose biosensor, it also provides a suitable platform for on-chip electrochemical sensing for other chemical agents and biomolecules.

  14. Transmutation of Personal Glucose Meters into Portable and Highly Sensitive Microbial Pathogen Detection Platform.

    Science.gov (United States)

    Wang, Zhenzhen; Chen, Zhaowei; Gao, Nan; Ren, Jinsong; Qu, Xiaogang

    2015-10-07

    Herein, for the first time, we presented a simple and general approach by using personal glucose meters (PGM) for portable and ultrasensitive detection of microbial pathogens. Upon addition of pathogenic bacteria, glucoamylase-quaternized magnetic nanoparticles (GA-QMNPS) conjugates were disrupted by the competitive multivalent interactions between bacteria and QMNPS, resulting in the release of GA. After magnetic separation, the free GA could catalyze the hydrolysis of amylose into glucose for quantitative readout by PGM. In such way, PGM was transmuted into a bacterial detection device and extremely low detection limits down to 20 cells mL(-1) was achieved. More importantly, QMNPS could inhibit the growth of the bacteria and destroy its cellular structure, which enabled bacteria detection and inhibition simultaneously. The simplicity, portability, sensitivity and low cost of presented work make it attractive for clinical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. A Highly Sensitive Nonenzymatic Glucose Biosensor Based on the Regulatory Effect of Glucose on Electrochemical Behaviors of Colloidal Silver Nanoparticles on MoS₂†.

    Science.gov (United States)

    Anderson, Kash; Poulter, Benjamin; Dudgeon, John; Li, Shu-En; Ma, Xiang

    2017-08-05

    A novel and highly sensitive nonenzymatic glucose biosensor was developed by nucleating colloidal silver nanoparticles (AgNPs) on MoS₂. The facile fabrication method, high reproducibility (97.5%) and stability indicates a promising capability for large-scale manufacturing. Additionally, the excellent sensitivity (9044.6 μA mM -1 cm -2 ), low detection limit (0.03 μM), appropriate linear range of 0.1-1000 μM, and high selectivity suggests that this biosensor has a great potential to be applied for noninvasive glucose detection in human body fluids, such as sweat and saliva.

  16. Higher Fasting Plasma Glucose Levels, within the Normal Range, are Associated with Decreased Processing Speed in High Functioning Young Elderly.

    Science.gov (United States)

    Raizes, Meytal; Elkana, Odelia; Franko, Motty; Ravona Springer, Ramit; Segev, Shlomo; Beeri, Michal Schnaider

    2016-01-01

    We explored the association of plasma glucose levels within the normal range with processing speed in high functioning young elderly, free of type 2 diabetes mellitus (T2DM). A sample of 41 participants (mean age = 64.7, SD = 10; glucose 94.5 mg/dL, SD = 9.3), were examined with a computerized cognitive battery. Hierarchical linear regression analysis showed that higher plasma glucose levels, albeit within the normal range (levels may have an impact on cognitive function.

  17. Development of a glucose-sensitive drug delivery device: Microencapsulated liposomes and poly(2-ethylacrylic acid)

    Science.gov (United States)

    Kanokpanont, Sorada

    The current study is the development a self-regulated, glucose responsive drug delivery system, using dioleoylphosphatidylcholine (DOPC) liposomes, a pH sensitive polymer, poly (2-ethylacrylic acid)(PEAA), and the feed back reaction of glucose with glucose oxidase enzyme (GO). The thesis investigates the use of PEAR and liposomes to work inside a microcapsule in response to the glucose level of the environment, by following the release of fluorescence probes, 8-aminonapthalene-1,3,6-trisulfonic acid, disodium salt/p-xylene-bis-pyridimuim bromide (ANTS/DPX) and a model protein, myoglobin. The continuing studies of PEAR and liposome interaction indicated an evidence of the previous hypothesis of two-mode release at different pHs. Differential scanning calorimetric studies of DOPC and PEAA complexes revealed the possibility of polymer adsorption to the liposomes in the pH range 5.5--7.0 and insertion in the liposome bilayer at pH pH, PEAR concentration, presence of cholesterol in the liposomes, Ca 2+, and the concentration of sodium alginate. We have also shown possibilities of anchoring PEAR on to liposome by covalent conjugation although this led to inactivation of the polymer. It is also possible to entrap small molecular weight PEAA in liposomes. The evidence of the pH-induced protein release by the interaction of PEAA and liposomes was first demonstrated in this thesis. Kinetic parameters of GO were estimated to use as a basis for determination optimal concentration in the capsules. The pH reduction inside the capsule due to GO reaction showed positive results for the use of GO in a non-buffered system. The procedure of liquid-core alginate capsules was modified to facilitate the pH-responsive release of ANTS/DPX and myoglobin. The capsules responded to high blood glucose concentration by releasing myoglobin within 30 minutes. Although more studies are required to improve the response of the system to the normal blood glucose and to control the total protein

  18. A novel glucose biosensor based on phosphonic acid-functionalized silica nanoparticles for sensitive detection of glucose in real samples

    International Nuclear Information System (INIS)

    Zhao, Wenbo; Fang, Yi; Zhu, Qinshu; Wang, Kuai; Liu, Min; Huang, Xiaohua; Shen, Jian

    2013-01-01

    An effective strategy for preparation amperometric biosensor by using the phosphonic acid-functionalized silica nanoparticles (PFSi NPs) as special modified materials is proposed. In such a strategy, glucose oxidase (GOD) was selected as model protein to fabricate glucose biosensor in the presence of phosphonic acid-functionalized silica nanoparticles (PFSi NPs). The PFSi NPs were first modified on the surface of glassy carbon (GC) electrode, then, GOD was adsorbed onto the PFSi NPs film by drop-coating. The PFSi NPs were characterized by transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR) spectra. The interaction of PFSi NPs with GOD was investigated by the circular dicroism spectroscopy (CD). The results showed PFSi NPs could essentially maintain the native conformation of GOD. The direct electron transfer of GOD on (PFSi NPs)/GCE electrode exhibited excellent electrocatalytic activity for the oxidation of glucose. The proposed biosensor modified with PFSi NPs displayed a fast amperometric response (5 s) to glucose, a good linear current–time relation over a wide range of glucose concentrations from 5.00 × 10 −4 to 1.87 × 10 −1 M, and a low detection limit of 2.44 × 10 −5 M (S/N = 3). Moreover, the biosensor can be used for assessment of the concentration of glucose in many real samples (relative error < 3%). The GOD biosensor modified with PFSi NPs will have essential meaning and practical application in future that attributed to the simple method of fabrication and good performance

  19. Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Khalilian, Alireza; Kang, Shin-Won

    2016-02-20

    In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt's dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance.

  20. Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane

    Directory of Open Access Journals (Sweden)

    Md. Rajibur Rahaman Khan

    2016-02-01

    Full Text Available In this paper, we proposed an interdigitated capacitor (IDC-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt’s dye (R-dye. These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC] and N,N-Dimethylacetamide (DMAC solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance.

  1. Effect of High Fat and High Sugar Diet on Glucose Tolerance, Insulin Response to Glucose Load and Insulin Sensitivity in Rats

    OpenAIRE

    岡﨑, 悟

    1987-01-01

    To investigate the precipitating effects of the westernized diet on diabetes mellitus, glucose tolerance and insulin response to oral glucose load (1.5g/kg body weight) and insulin sensitivity to exogenous insulin (0.2U/kg) were studied in rats fed an experimental diet for 8 weeks. Four experimental diets were used : low fat-no sugar diet (energy ratio of 10% fat, 70% starch, a model of the traditional Japanese diet), high fat-high sugar diet (40% fat, 20% starch, 20% sugar, a model of the we...

  2. Enhanced leptin sensitivity and improved glucose homeostasis in mice lacking suppressor of cytokine signaling-3 in POMC-expressing cells.

    Science.gov (United States)

    Kievit, Paul; Howard, Jane K; Badman, Michael K; Balthasar, Nina; Coppari, Roberto; Mori, Hiroyuki; Lee, Charlotte E; Elmquist, Joel K; Yoshimura, Akihiko; Flier, Jeffrey S

    2006-08-01

    Suppressor of cytokine signaling-3 (Socs-3) negatively regulates the action of various cytokines, as well as the metabolic hormones leptin and insulin. Mice with haploinsufficiency of Socs-3, or those with neuronal deletion of Socs-3, are lean and more leptin and insulin sensitive. To examine the role of Socs-3 within specific neurons critical to energy balance, we created mice with selective deletion of Socs-3 within pro-opiomelanocortin (POMC)-expressing cells. These mice had enhanced leptin sensitivity, measured by weight loss and food intake after leptin infusion. On chow diet, glucose homeostasis was improved despite normal weight gain. On a high-fat diet, the rate of weight gain was reduced, due to increased energy expenditure rather than decreased food intake; glucose homeostasis and insulin sensitivity were substantially improved. These studies demonstrate that Socs-3 within POMC neurons regulates leptin sensitivity and glucose homeostasis, and plays a key role in linking high-fat diet to disordered metabolism.

  3. Insulin sensitivity of hepatic glucose and lipid metabolism in animal models of hepatic steatosis

    NARCIS (Netherlands)

    Grefhorst, Aldo

    2006-01-01

    De lever is betrokken bij de regulatie van zowel het koolhydraat als het vet metabolisme. De lever slaat glucose op als glycogeen, scheidt glucose uit, kan glucose maken uit bijvoorbeeld melkzuur en aminozuren (‘gluconeogenese’), zet glucose om in vet (‘de novo lipogenese’), verbrandt vetzuren in de

  4. Spherulitic copper–copper oxide nanostructure-based highly sensitive nonenzymatic glucose sensor

    Directory of Open Access Journals (Sweden)

    Das G

    2015-08-01

    Full Text Available Gautam Das, Thao Quynh Ngan Tran, Hyon Hee Yoon Department of Chemical and Biological Engineering, Gachon University, Seongnam, Republic of South Korea Abstract: In this work, three different spherulitic nanostructures Cu–CuOA, Cu–CuOB, and Cu–CuOC were synthesized in water-in-oil microemulsions by varying the surfactant concentration (30 mM, 40 mM, and 50 mM, respectively. The structural and morphological characteristics of the Cu–CuO nanostructures were investigated by ultraviolet–visible (UV–vis spectroscopy, X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy techniques. The synthesized nanostructures were deposited on multiwalled carbon nanotube (MWCNT-modified indium tin oxide (ITO electrodes to fabricate a nonenzymatic highly sensitive amperometric glucose sensor. The performance of the ITO/MWCNT/Cu–CuO electrodes in the glucose assay was examined by cyclic voltammetry and chronoamperometric studies. The sensitivity of the sensor varied with the spherulite type; Cu–CuOA, Cu–CuOB, and Cu–CuOC exhibited a sensitivity of 1,229, 3,012, and 3,642 µA mM-1·cm-2, respectively. Moreover, the linear range is dependent on the structure types: 0.023–0.29 mM, 0.07–0.8 mM, and 0.023–0.34 mM for Cu–CuOA, Cu–CuOB, and Cu–CuOC, respectively. An excellent response time of 3 seconds and a low detection limit of 2 µM were observed for Cu–CuOB at an applied potential of +0.34 V. In addition, this electrode was found to be resistant to interference by common interfering agents such as urea, cystamine, l-ascorbic acid, and creatinine. The high performance of the Cu–CuO spherulites with nanowire-to-nanorod outgrowths was primarily due to the high surface area and stability, and good three-dimensional structure. Furthermore, the ITO/MWCNT/Cu–CuOB electrode applied to real urine and serum sample showed satisfactory performance. Keywords: copper oxide, multiwalled

  5. Sensitive Nonenzymatic Electrochemical Glucose Detection Based on Hollow Porous NiO

    Science.gov (United States)

    He, Gege; Tian, Liangliang; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Pu, Wanrong; Zhang, Jinkun; Li, Lu

    2018-01-01

    Transition metal oxides (TMOs) have attracted extensive research attentions as promising electrocatalytic materials. Despite low cost and high stability, the electrocatalytic activity of TMOs still cannot satisfy the requirements of applications. Inspired by kinetics, the design of hollow porous structure is considered as a promising strategy to achieve superior electrocatalytic performance. In this work, cubic NiO hollow porous architecture (NiO HPA) was constructed through coordinating etching and precipitating (CEP) principle followed by post calcination. Being employed to detect glucose, NiO HPA electrode exhibits outstanding electrocatalytic activity in terms of high sensitivity (1323 μA mM-1 cm-2) and low detection limit (0.32 μM). The excellent electrocatalytic activity can be ascribed to large specific surface area (SSA), ordered diffusion channels, and accelerated electron transfer rate derived from the unique hollow porous features. The results demonstrate that the NiO HPA could have practical applications in the design of nonenzymatic glucose sensors. The construction of hollow porous architecture provides an effective nanoengineering strategy for high-performance electrocatalysts.

  6. Stimulatory effect of insulin on glucose uptake by muscle involves the central nervous system in insulin-sensitive mice.

    Science.gov (United States)

    Coomans, Claudia P; Biermasz, Nienke R; Geerling, Janine J; Guigas, Bruno; Rensen, Patrick C N; Havekes, Louis M; Romijn, Johannes A

    2011-12-01

    Insulin inhibits endogenous glucose production (EGP) and stimulates glucose uptake in peripheral tissues. Hypothalamic insulin signaling is required for the inhibitory effects of insulin on EGP. We examined the contribution of central insulin signaling on circulating insulin-stimulated tissue-specific glucose uptake. Tolbutamide, an inhibitor of ATP-sensitive K(+) channels (K(ATP) channels), or vehicle was infused into the lateral ventricle in the basal state and during hyperinsulinemic-euglycemic conditions in postabsorptive, chow-fed C57Bl/6J mice and in postabsorptive C57Bl/6J mice with diet-induced obesity. Whole-body glucose uptake was measured by d-[(14)C]glucose kinetics and tissue-specific glucose uptake by 2-deoxy-d-[(3)H]glucose uptake. During clamp conditions, intracerebroventricular administration of tolbutamide impaired the ability of insulin to inhibit EGP by ∼20%. In addition, intracerebroventricular tolbutamide diminished insulin-stimulated glucose uptake in muscle (by ∼59%) but not in heart or adipose tissue. In contrast, in insulin-resistant mice with diet-induced obesity, intracerebroventricular tolbutamide did not alter the effects of insulin during clamp conditions on EGP or glucose uptake by muscle. Insulin stimulates glucose uptake in muscle in part through effects via K(ATP) channels in the central nervous system, in analogy with the inhibitory effects of insulin on EGP. High-fat diet-induced obesity abolished the central effects of insulin on liver and muscle. These observations stress the role of central insulin resistance in the pathophysiology of diet-induced insulin resistance.

  7. Could Continuous Glucose Monitoring Facilitate Identifying Diabetes Patients with a Higher Risk of Hypoglycemia during Driving?

    Czech Academy of Sciences Publication Activity Database

    Brož, J.; Doničová, V.; Brabec, Marek; Janíčková Žďárská, D.; Polák, J.

    2013-01-01

    Roč. 7, č. 6 (2013), s. 1644-1645 ISSN 1932-2968 Institutional support: RVO:67985807 Keywords : continuous glucose monitoring * driving * hypoglycemia * insulin pump * prevention * type 1 diabetes mellitus Subject RIV: BB - Applied Statistics, Operational Research http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3876343/

  8. Insulin sensitivity of hepatic glucose and lipid metabolism in animal models of hepatic steatosis

    OpenAIRE

    Grefhorst, Aldo

    2006-01-01

    De lever is betrokken bij de regulatie van zowel het koolhydraat als het vet metabolisme. De lever slaat glucose op als glycogeen, scheidt glucose uit, kan glucose maken uit bijvoorbeeld melkzuur en aminozuren (‘gluconeogenese’), zet glucose om in vet (‘de novo lipogenese’), verbrandt vetzuren in de beta-oxidatie (levert energie voor de gluconeogenese) en scheidt triglycerides uit in de circulatie in ‘very low density lipoprotein’ (VLDL) deeltjes. Insuline remt de glucoseproductie door de lev...

  9. High Sensitivity and High Detection Specificity of Gold-Nanoparticle-Grafted Nanostructured Silicon Mass Spectrometry for Glucose Analysis.

    Science.gov (United States)

    Tsao, Chia-Wen; Yang, Zhi-Jie

    2015-10-14

    Desorption/ionization on silicon (DIOS) is a high-performance matrix-free mass spectrometry (MS) analysis method that involves using silicon nanostructures as a matrix for MS desorption/ionization. In this study, gold nanoparticles grafted onto a nanostructured silicon (AuNPs-nSi) surface were demonstrated as a DIOS-MS analysis approach with high sensitivity and high detection specificity for glucose detection. A glucose sample deposited on the AuNPs-nSi surface was directly catalyzed to negatively charged gluconic acid molecules on a single AuNPs-nSi chip for MS analysis. The AuNPs-nSi surface was fabricated using two electroless deposition steps and one electroless etching step. The effects of the electroless fabrication parameters on the glucose detection efficiency were evaluated. Practical application of AuNPs-nSi MS glucose analysis in urine samples was also demonstrated in this study.

  10. Copeptin, a surrogate marker for arginine vasopressin secretion, is associated with higher glucose and insulin concentrations but not higher blood pressure in obese men

    DEFF Research Database (Denmark)

    Asferg, C L; Andersen, Ulrik Bjørn; Linneberg, A

    2014-01-01

    distribution. METHODS: In 103 obese men (mean age ± standard deviation: 49.4 ± 10.2 years) and 27 normal weight control men (mean age: 51.5 ± 8.4 years), taking no medication, we measured 24-h ambulatory blood pressure, fasting blood concentrations of copeptin, lipids, glucose and insulin, and determined body...... blood pressure (r = 0.11, P = 0.29), 24-h diastolic blood pressure (r = 0.11, P = 0.28), BMI (r = 0.09, P = 0.37), total body fatness percentage (r = 0.10, P = 0.33), android fat mass percentage (r = 0.04, P = 0.66) or serum triglyceride concentrations (r = 0.04; P = 0.68). In contrast, plasma copeptin......, and is associated with abnormalities in glucose and insulin metabolism, but not with higher blood pressure or an android fat distribution in obese men....

  11. Lactose in milk replacer can partly be replaced by glucose, fructose, or glycerol without affecting insulin sensitivity in veal calves

    NARCIS (Netherlands)

    Pantophlet, A. J.; Gilbert, M. S.; van den Borne, J. J. G. C.; Gerrits, W. J. J.; Roelofsen, H.; Priebe, M. G.; Vonk, R. J.

    Calf milk replacer (MR) contains 40 to 50% lactose. Lactose strongly fluctuates in price and alternatives are desired. Also, problems with glucose homeostasis and insulin sensitivity (i.e., high incidence of hyperglycemia and hyperinsulinemia) have been described for heavy veal calves (body weight

  12. Deletion of hepatic carbohydrate response element binding protein (ChREBP impairs glucose homeostasis and hepatic insulin sensitivity in mice

    Directory of Open Access Journals (Sweden)

    Tara Jois

    2017-11-01

    Conclusions: Overall, hepatic ChREBP is protective in regards to hepatic insulin sensitivity and whole body glucose homeostasis. Hepatic ChREBP action can influence other peripheral tissues and is likely essential in coordinating the body's response to different feeding states.

  13. Cucurbitane Triterpenoids from the Fruits of Momordica Charantia Improve Insulin Sensitivity and Glucose Homeostasis in Streptozotocin-Induced Diabetic Mice.

    Science.gov (United States)

    Han, Joo-Hui; Tuan, Nguyen Quoc; Park, Min-Ho; Quan, Khong Trong; Oh, Joonseok; Heo, Kyung-Sun; Na, MinKyun; Myung, Chang-Seon

    2018-04-01

    Momordica charantia (M. charantia) has antidiabetic effects, and cucurbitane-type triterpenoid is one of the compounds of M. charantia. This study aims to investigate whether the new cucurbitane-type triterpenoids affect insulin sensitivity both in vitro and in vivo, and the underlying mechanisms. Four compounds (C1-C4) isolated from the ethanol extract of M. charantia enhance glucose uptake in C2C12 myotubes via insulin receptor substrate-1 (IRS-1) rather than via adenosine monophosphate-activated protein kinase. The most potent, compound 2 (C2), significantly increases the activation of IRS-1 and downstream signaling pathways, resulting in glucose transporter 4 translocation. Furthermore, these C2-induced in vitro effects are blocked by specific signal inhibitors. We further evaluate the antidiabetic effect of C2 using a streptozotocin (STZ)-induced diabetic mouse model. Consistent with in vitro data, treatment with C2 (1.68 mg kg -1 ) significantly decreases blood glucose level and enhances glycogen storage in STZ-injected mice. These effects appear to be mediated by the IRS-1 signaling pathway in skeletal muscle, not in adipose and liver tissues, suggesting that C2 improves hyperglycemia by increasing glucose uptake into skeletal muscle. Our findings demonstrate that the new cucurbitane-type triterpenoids have potential for prevention and management of diabetes by improving insulin sensitivity and glucose homeostasis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Effects of ambient temperature on glucose tolerance and insulin sensitivity test outcomes in normal and obese C57 male mice.

    Science.gov (United States)

    Dudele, Anete; Rasmussen, Gitte Marie; Mayntz, David; Malte, Hans; Lund, Sten; Wang, Tobias

    2015-05-01

    Mice are commonly used as animal models to study human metabolic diseases, but experiments are typically performed at room temperature, which is far below their thermoneutral zone and is associated with elevated heart rate, food intake, and energy expenditure. We set out to study how ambient temperature affects glucose tolerance and insulin sensitivity in control and obese male mice. Adult male C57BL/6J mice were housed at room temperature (23°C) for 6 weeks and fed either control or high fat diet. They were then fasted for 6 h before glucose or insulin tolerance tests were performed at 15, 20, 25, or 30°C. To ensure that behavioral thermoregulation did not counterbalance the afflicted ambient temperatures, oxygen consumption was determined on mice with the same thermoregulatory opportunities as during the tests. Decreasing ambient temperatures increased oxygen consumption and body mass loss during fasting in both groups. Mice fed high fat diet had improved glucose tolerance at 30°C and increased levels of fasting insulin followed by successive decrease of fasting glucose. However, differences between control and high-fat diet mice were present at all temperatures. Ambient temperature did not affect glucose tolerance in control group and insulin tolerance in either of the groups. Ambient temperature affects glucose metabolism in mice and this effect is phenotype specific. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  15. Brain GLUT4 Knockout Mice Have Impaired Glucose Tolerance, Decreased Insulin Sensitivity, and Impaired Hypoglycemic Counterregulation.

    Science.gov (United States)

    Reno, Candace M; Puente, Erwin C; Sheng, Zhenyu; Daphna-Iken, Dorit; Bree, Adam J; Routh, Vanessa H; Kahn, Barbara B; Fisher, Simon J

    2017-03-01

    GLUT4 in muscle and adipose tissue is important in maintaining glucose homeostasis. However, the role of insulin-responsive GLUT4 in the central nervous system has not been well characterized. To assess its importance, a selective knockout of brain GLUT4 (BG4KO) was generated by crossing Nestin-Cre mice with GLUT4-floxed mice. BG4KO mice had a 99% reduction in GLUT4 protein expression throughout the brain. Despite normal feeding and fasting glycemia, BG4KO mice were glucose intolerant, demonstrated hepatic insulin resistance, and had reduced glucose uptake in the brain. In response to hypoglycemia, BG4KO mice had impaired glucose sensing, noted by impaired epinephrine and glucagon responses and impaired c-fos activation in the hypothalamic paraventricular nucleus. Moreover, in vitro glucose sensing of glucose-inhibitory neurons from the ventromedial hypothalamus was impaired in BG4KO mice. In summary, BG4KO mice are glucose intolerant, insulin resistant, and have impaired glucose sensing, indicating a critical role for brain GLUT4 in sensing and responding to changes in blood glucose. © 2017 by the American Diabetes Association.

  16. Brain GLUT4 Knockout Mice Have Impaired Glucose Tolerance, Decreased Insulin Sensitivity, and Impaired Hypoglycemic Counterregulation

    Science.gov (United States)

    Reno, Candace M.; Puente, Erwin C.; Sheng, Zhenyu; Daphna-Iken, Dorit; Bree, Adam J.; Routh, Vanessa H.; Kahn, Barbara B.

    2017-01-01

    GLUT4 in muscle and adipose tissue is important in maintaining glucose homeostasis. However, the role of insulin-responsive GLUT4 in the central nervous system has not been well characterized. To assess its importance, a selective knockout of brain GLUT4 (BG4KO) was generated by crossing Nestin-Cre mice with GLUT4-floxed mice. BG4KO mice had a 99% reduction in GLUT4 protein expression throughout the brain. Despite normal feeding and fasting glycemia, BG4KO mice were glucose intolerant, demonstrated hepatic insulin resistance, and had reduced glucose uptake in the brain. In response to hypoglycemia, BG4KO mice had impaired glucose sensing, noted by impaired epinephrine and glucagon responses and impaired c-fos activation in the hypothalamic paraventricular nucleus. Moreover, in vitro glucose sensing of glucose-inhibitory neurons from the ventromedial hypothalamus was impaired in BG4KO mice. In summary, BG4KO mice are glucose intolerant, insulin resistant, and have impaired glucose sensing, indicating a critical role for brain GLUT4 in sensing and responding to changes in blood glucose. PMID:27797912

  17. Brown adipose tissue improves whole-body glucose homeostasis and insulin sensitivity in humans

    Science.gov (United States)

    Brown adipose tissue (BAT) has attracted scientific interest as an antidiabetic tissue owing to its ability to dissipate energy as heat. Despite a plethora of data concerning the role of BAT in glucose metabolism in rodents, the role of BAT (if any) in glucose metabolism in humans remains unclear. T...

  18. The dipeptidyl peptidase-4 inhibitor vildagliptin improves beta-cell function and insulin sensitivity in subjects with impaired fasting glucose

    DEFF Research Database (Denmark)

    Utzschneider, Kristina M; Tong, Jenny; Montgomery, Brenda

    2007-01-01

    OBJECTIVE: To evaluate the effect of treatment with the dipeptidyl peptidase (DPP)-4 inhibitor vildagliptin on insulin sensitivity and beta-cell function in subjects with impaired fasting glucose (IFG). RESEARCH DESIGN AND METHODS: A total of 22 subjects with IFG (11 female and 11 male, mean +/- SD...... age 59.6 +/- 11.5 years) were treated orally with 100 mg vildagliptin once daily in a single-blind study. Subjects received placebo for 2 weeks (run-in) followed by vildagliptin for 6 weeks (treatment) and then placebo for 2 weeks (washout). A frequently sampled intravenous glucose tolerance test....... RESULTS: Fasting plasma glucose did not change after 6 weeks of vildagliptin treatment. With treatment, mean +/- SEM AIR(g) increased from 224 +/- 44 to 286 +/- 52 pmol/l (P

  19. Graphitic Carbon Nitride Nanosheets-Based Ratiometric Fluorescent Probe for Highly Sensitive Detection of H2O2 and Glucose.

    Science.gov (United States)

    Liu, Jin-Wen; Luo, Ying; Wang, Yu-Min; Duan, Lu-Ying; Jiang, Jian-Hui; Yu, Ru-Qin

    2016-12-14

    Graphitic carbon nitride (g-C 3 N 4 ) nanosheets, an emerging graphene-like carbon-based nanomaterial with high fluorescence and large specific surface areas, hold great potential for biosensor applications. Current g-C 3 N 4 nanosheets based fluorescent biosensors majorly rely on single fluorescent intensity reading through fluorescence quenching interactions between the nanosheets and metal ions. Here we report for the first time the development of a novel g-C 3 N 4 nanosheets-based ratiometric fluorescence sensing strategy for highly sensitive detection of H 2 O 2 and glucose. With o-phenylenediamine (OPD) oxidized by H 2 O 2 in the presence of horseradish peroxidase (HRP), the oxidization product can assemble on the g-C 3 N 4 nanosheets through hydrogen bonding and π-π stacking, which effectively quenches the fluorescence of g-C 3 N 4 while delivering a new emission peak. The ratiometric signal variations enable robust and sensitive detection of H 2 O 2 . On the basis of the glucose converting into H 2 O 2 through the catalysis of glucose oxidase, the g-C 3 N 4 -based ratiometric fluorescence sensing platform is also exploited for glucose assay. The developed strategy is demonstrated to give a detection limit of 50 nM for H 2 O 2 and 0.4 μM for glucose, at the same time, it has been successfully used for glucose levels detection in human serum. This strategy may provide a cost-efficient, robust, and high-throughput platform for detecting various species involving H 2 O 2 -generation reactions for biomedical applications.

  20. The product of triglycerides and glucose, a simple measure of insulin sensitivity. Comparison with the euglycemic-hyperinsulinemic clamp.

    Science.gov (United States)

    Guerrero-Romero, Fernando; Simental-Mendía, Luis E; González-Ortiz, Manuel; Martínez-Abundis, Esperanza; Ramos-Zavala, María G; Hernández-González, Sandra O; Jacques-Camarena, Omar; Rodríguez-Morán, Martha

    2010-07-01

    To meet the worldwide challenge of emerging diabetes, accessible and inexpensive tests to identify insulin resistance are needed. To evaluate the sensitivity and specificity of the product of fasting, we compared the triglycerides and glucose (TyG) index, a simple measure of insulin resistance, with the euglycemic-hyperinsulinemic clamp test. We conducted a cross-sectional study of the general population and outpatients of the Internal Medicine Department at the Medical Unit of High Specialty of the Specialty Hospital at the West National Medical Center in Guadalajara, Mexico. Eleven nonobese healthy subjects, 34 obese normal glucose tolerance individuals, 22 subjects with prediabetes, and 32 diabetic patients participated in the study. We performed a euglycemic-hyperinsulinemic clamp test. Sensitivity and specificity of the TyG index [Ln(fasting triglycerides) (mg/dl) x fasting glucose (mg/dl)/2] were measured, as well as the area under the curve of the receiver operating characteristic scatter plot and the correlation between the TyG index and the total glucose metabolism (M) rates. Pearson's correlation coefficient between the TyG index and M rates was -0.681 (P index and M rates was similar between men (-0.740) and women (-0.730), nonobese (-0.705) and obese (-0.710), and nondiabetic (-0.670) and diabetic (-0.690) individuals. The best value of the TyG index for diagnosis of insulin resistance was 4.68, which showed the highest sensitivity (96.5%) and specificity (85.0%; area under the curve + 0.858). The TyG index has high sensitivity and specificity, suggesting that it could be useful for identification of subjects with decreased insulin sensitivity.

  1. Addressing glucose sensitivity measured by F-18 FDG PET in lung cancers for radiation treatment planning and monitoring

    International Nuclear Information System (INIS)

    Wong, Ching-yee Oliver; Thie, Joseph; Gaskill, Marianne; Kestin, Larry; Yan Di; Cheng, Vincent; Nagle, Conrad

    2006-01-01

    Purpose: To address glucose sensitivity in lung cancers before and after radiation treatment (Tx). Methods and Materials: Twelve patients were each studied with two pre-Tx positron emission tomography (PET) scans and 3 patients each with one post-Tx PET scan, with glucose concentration [Glc] and maximum standard uptake value (SUV) recorded. The pre-Tx glucose sensitivity, g from SUV 1 /SUV 2 = {[Glc] 1 /[Glc] 2 } g and Tx index, τ from SUV post-Tx /SUV pre-Tx = {[Glc] post-Tx /[Glc] pre-Tx } τ was calculated by linear regression. Pre-Tx SUVs were corrected to post-Tx Glc with g (SUV' pre-Tx ) for a pure Tx effect, R ln(SUV post-Tx /SUV' pre-Tx ). Results: There were no significant differences in SUV but [Glc] were different (96.4 ± 10.9 vs. 88.3 ± 10.5, p = 0.015) between two pre-Tx PET scans. Linear regression yielded g -0.79 and τ = -1.78 to -2.41 (p < 0.0005 in all). The %ΔSUV after Tx for 3 patients without vs. with g correction were different by -12%, 0%, and + 7%, suggesting varying effects from glucose. R values were also different and mean R (-0.81 ± 0.38) was significantly different from zero (p = 0.03), consistent with successful Tx as confirmed by clinico-radiologic follow-up. Conclusions: The extra dimension of glucose sensitivity, g besides SUV incorporated in the combined Tx-derived τ may be a useful global Tx evaluation index even with differing [Glc

  2. Consumption of meat is associated with higher fasting glucose and insulin concentrations regardless of glucose and insulin genetic risk scores: a meta-analysis of 50,345 Caucasians12

    Science.gov (United States)

    Fretts, Amanda M; Follis, Jack L; Nettleton, Jennifer A; Lemaitre, Rozenn N; Ngwa, Julius S; Wojczynski, Mary K; Kalafati, Ioanna Panagiota; Varga, Tibor V; Frazier-Wood, Alexis C; Houston, Denise K; Lahti, Jari; Ericson, Ulrika; van den Hooven, Edith H; Mikkilä, Vera; Kiefte-de Jong, Jessica C; Mozaffarian, Dariush; Rice, Kenneth; Renström, Frida; North, Kari E; McKeown, Nicola M; Feitosa, Mary F; Kanoni, Stavroula; Smith, Caren E; Garcia, Melissa E; Tiainen, Anna-Maija; Sonestedt, Emily; Manichaikul, Ani; van Rooij, Frank JA; Dimitriou, Maria; Raitakari, Olli; Pankow, James S; Djoussé, Luc; Province, Michael A; Hu, Frank B; Lai, Chao-Qiang; Keller, Margaux F; Perälä, Mia-Maria; Rotter, Jerome I; Hofman, Albert; Graff, Misa; Kähönen, Mika; Mukamal, Kenneth; Johansson, Ingegerd; Ordovas, Jose M; Liu, Yongmei; Männistö, Satu; Uitterlinden, André G; Deloukas, Panos; Seppälä, Ilkka; Psaty, Bruce M; Cupples, L Adrienne; Borecki, Ingrid B; Franks, Paul W; Arnett, Donna K; Nalls, Mike A; Eriksson, Johan G; Orho-Melander, Marju; Franco, Oscar H; Lehtimäki, Terho; Dedoussis, George V; Meigs, James B; Siscovick, David S

    2015-01-01

    Background: Recent studies suggest that meat intake is associated with diabetes-related phenotypes. However, whether the associations of meat intake and glucose and insulin homeostasis are modified by genes related to glucose and insulin is unknown. Objective: We investigated the associations of meat intake and the interaction of meat with genotype on fasting glucose and insulin concentrations in Caucasians free of diabetes mellitus. Design: Fourteen studies that are part of the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium participated in the analysis. Data were provided for up to 50,345 participants. Using linear regression within studies and a fixed-effects meta-analysis across studies, we examined 1) the associations of processed meat and unprocessed red meat intake with fasting glucose and insulin concentrations; and 2) the interactions of processed meat and unprocessed red meat with genetic risk score related to fasting glucose or insulin resistance on fasting glucose and insulin concentrations. Results: Processed meat was associated with higher fasting glucose, and unprocessed red meat was associated with both higher fasting glucose and fasting insulin concentrations after adjustment for potential confounders [not including body mass index (BMI)]. For every additional 50-g serving of processed meat per day, fasting glucose was 0.021 mmol/L (95% CI: 0.011, 0.030 mmol/L) higher. Every additional 100-g serving of unprocessed red meat per day was associated with a 0.037-mmol/L (95% CI: 0.023, 0.051-mmol/L) higher fasting glucose concentration and a 0.049–ln-pmol/L (95% CI: 0.035, 0.063–ln-pmol/L) higher fasting insulin concentration. After additional adjustment for BMI, observed associations were attenuated and no longer statistically significant. The association of processed meat and fasting insulin did not reach statistical significance after correction for multiple comparisons. Observed associations were not modified by genetic

  3. Enhanced electrochemical sensitivity of enzyme precipitate coating (EPC)-based glucose oxidase biosensors with increased free CNT loadings.

    Science.gov (United States)

    Kim, Jae Hyun; Jun, Sun-Ae; Kwon, Yongchai; Ha, Su; Sang, Byong-In; Kim, Jungbae

    2015-02-01

    Enzymatic electrodes were fabricated by using three different immobilizations of glucose oxidase (GOx): covalent enzyme attachment (CA), enzyme coating (EC), and enzyme precipitate coating (EPC), here referred to as CA-E, EC-E, and EPC-E, respectively. When additional carbon nanotubes (CNTs) were introduced from 0 to 75wt% for the EPC-E design, its initial biosensor sensitivity was improved from 2.40×10(-3) to 16.26×10(-3) A∙M(-1)∙cm(-2), while its electron charge transfer rate constant was increased from 0.33 to 1.47s(-1). When a fixed ratio of CNTs was added for three different electrode systems, EPC-E showed the best glucose sensitivity and long-term thermal stability. For example, when 75wt% of additional CNTs was added, the initial sensitivity of EPC-E was 16.26×10(-3) A∙M(-1)∙cm(-2), while those of EC-E and CA-E were only 6.42×10(-3) and 1.18×10(-3) A∙M(-1)∙cm(-2), respectively. Furthermore, EPC-E retained 63% of its initial sensitivity after thermal treatment at 40°C over 41days, while EC-E and CA-E showed only 12% and 1% of initial sensitivities, respectively. Consequently, the EPC approach with additional CNTs achieved both high sensitivity and long-term stability, which are required for continuous and accurate glucose monitoring. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Arctigenin suppresses unfolded protein response and sensitizes glucose deprivation-mediated cytotoxicity of cancer cells.

    Science.gov (United States)

    Sun, Shengrong; Wang, Xiong; Wang, Changhua; Nawaz, Ahmed; Wei, Wen; Li, Juanjuan; Wang, Lijun; Yu, De-Hua

    2011-01-01

    The involvement of unfolded protein response (UPR) activation in tumor survival and resistance to chemotherapies suggests a new anticancer strategy targeting UPR pathway. Arctigenin, a natural product, has been recently identified for its antitumor activity with selective toxicity against cancer cells under glucose starvation with unknown mechanism. Here we found that arctigenin specifically blocks the transcriptional induction of two potential anticancer targets, namely glucose-regulated protein-78 (GRP78) and its analog GRP94, under glucose deprivation, but not by tunicamycin. The activation of other UPR pathways, e.g., XBP-1 and ATF4, by glucose deprivation was also suppressed by arctigenin. A further transgene experiment showed that ectopic expression of GRP78 at least partially rescued arctigenin/glucose starvation-mediated cell growth inhibition, suggesting the causal role of UPR suppression in arctigenin-mediated cytotoxicity under glucose starvation. These observations bring a new insight into the mechanism of action of arctigenin and may lead to the design of new anticancer therapeutics. © Georg Thieme Verlag KG Stuttgart · New York.

  5. Higher glucose, insulin and insulin resistance (HOMA-IR) in childhood predict adverse cardiovascular risk in early adulthood: the Pune Children's Study.

    Science.gov (United States)

    Yajnik, Chittaranjan S; Katre, Prachi A; Joshi, Suyog M; Kumaran, Kalyanaraman; Bhat, Dattatray S; Lubree, Himangi G; Memane, Nilam; Kinare, Arun S; Pandit, Anand N; Bhave, Sheila A; Bavdekar, Ashish; Fall, Caroline H D

    2015-07-01

    The Pune Children's Study aimed to test whether glucose and insulin measurements in childhood predict cardiovascular risk factors in young adulthood. We followed up 357 participants (75% follow-up) at 21 years of age who had undergone detailed measurements at 8 years of age (glucose, insulin, HOMA-IR and other indices). Oral glucose tolerance, anthropometry, plasma lipids, BP, carotid intima-media thickness (IMT) and arterial pulse wave velocity (PWV) were measured at 21 years. Higher fasting glucose, insulin and HOMA-IR at 8 years predicted higher glucose, insulin, HOMA-IR, BP, lipids and IMT at 21 years. A 1 SD change in 8 year variables was associated with a 0.10-0.27 SD change at 21 years independently of obesity/adiposity at 8 years of age. A greater rise in glucose-insulin variables between 8 and 21 years was associated with higher cardiovascular risk factors, including PWV. Participants whose HOMA-IR measurement remained in the highest quartile (n = 31) had a more adverse cardiovascular risk profile compared with those whose HOMA-IR measurement remained in the lowest quartile (n = 28). Prepubertal glucose-insulin metabolism is associated with adult cardiovascular risk and markers of atherosclerosis. Our results support interventions to improve glucose-insulin metabolism in childhood to reduce cardiovascular risk in later life.

  6. Fabrication of gallium hexacyanoferrate modified carbon ionic liquid paste electrode for sensitive determination of hydrogen peroxide and glucose

    International Nuclear Information System (INIS)

    Haghighi, Behzad; Khosravi, Mehdi; Barati, Ali

    2014-01-01

    Gallium hexacyanoferrate (GaHCFe) and graphite powder were homogeneously dispersed into n-dodecylpyridinium hexafluorophosphate and paraffin to fabricate GaHCFe modified carbon ionic liquid paste electrode (CILPE). Mixture experimental design was employed to optimize the fabrication of GaHCFe modified CILPE (GaHCFe-CILPE). A pair of well-defined redox peaks due to the redox reaction of GaHCFe through one-electron process was observed for the fabricated electrode. The fabricated GaHCFe-CILPE exhibited good electrocatalytic activity towards reduction and oxidation of H 2 O 2 . The observed sensitivities for the electrocatalytic oxidation and reduction of H 2 O 2 at the operating potentials of + 0.8 and − 0.2 V were about 13.8 and 18.3 mA M −1 , respectively. The detection limit (S/N = 3) for H 2 O 2 was about 1 μM. Additionally, glucose oxidase (GOx) was immobilized on GaHCFe-CILPE using two methodology, entrapment into Nafion matrix and cross-linking with glutaraldehyde and bovine serum albumin, in order to fabricate glucose biosensor. Linear dynamic rage, sensitivity and detection limit for glucose obtained by the biosensor fabricated using cross-linking methodology were 0.1–6 mM, 0.87 mA M −1 and 30 μM, respectively and better than those obtained (0.2–6 mM, 0.12 mA M −1 and 50 μM) for the biosensor fabricated using entrapment methodology. - Highlights: • Gallium hexacyanoferrate modified carbon ionic liquid paste electrode was fabricated. • Mixture experimental design was used to optimize electrode fabrication. • Response trace plot was used to show the effect of electrode materials on response. • The sensor exhibited electrocatalytic activity towards H 2 O 2 reduction and oxidation. • Glucose biosensor was fabricated by immobilization of glucose oxidase on sensor

  7. Sensitive colorimetric assay for uric acid and glucose detection based on multilayer-modified paper with smartphone as signal readout.

    Science.gov (United States)

    Wang, Xu; Li, Fang; Cai, Ziqi; Liu, Kaifan; Li, Jing; Zhang, Boyang; He, Jianbo

    2018-04-01

    In this work, a multilayer-modified paper-based colorimetric sensing platform with improved color uniformity and intensity was developed for the sensitive and selective determination of uric acid and glucose with smartphone as signal readout. In detail, chitosan, different kinds of chromogenic reagents, and horseradish peroxidase (HRP) combined with a specific oxidase, e.g., uricase or glucose oxidase (GOD), were immoblized onto the paper substrate to form a multilayer-modified test paper. Hydrogen peroxide produced by the oxidases (uricase or GOD) reacts with the substrates (uric acid or glucose), and could oxidize the co-immoblized chromogenic reagents to form colored products with HRP as catalyst. A simple strategy by placing the test paper on top of a light-emitting diode lamp was adopted to efficiently prevent influence from the external light. The color images were recorded by the smartphone camera, and then the gray values of the color images were calculated for quantitative analysis. The developed method provided a wide linear response from 0.01 to 1.0 mM for uric acid detection and from 0.02 to 4.0 mM for glucose detection, with a limit of detection (LOD) as low as 0.003 and 0.014 mM, respectively, which was much lower than for previously reported paper-based colorimetric assays. The proposed assays were successfully applied to uric acid and glucose detection in real serum samples. Furthermore, the enhanced analytical performance of the proposed method allowed the non-invasive detection of glucose levels in tear samples, which holds great potential for point-of-care analysis. Graphical abstract ᅟ.

  8. Validation of different measures of insulin sensitivity of glucose metabolism in dairy cows using the hyperinsulinemic euglycemic clamp test as the gold standard.

    Science.gov (United States)

    De Koster, J; Hostens, M; Hermans, K; Van den Broeck, W; Opsomer, G

    2016-10-01

    The aim of the present research was to compare different measures of insulin sensitivity in dairy cows at the end of the dry period. To do so, 10 clinically healthy dairy cows with a varying body condition score were selected. By performing hyperinsulinemic euglycemic clamp (HEC) tests, we previously demonstrated a negative association between the insulin sensitivity and insulin responsiveness of glucose metabolism and the body condition score of these animals. In the same animals, other measures of insulin sensitivity were determined and the correlation with the HEC test, which is considered as the gold standard, was calculated. Measures derived from the intravenous glucose tolerance test (IVGTT) are based on the disappearance of glucose after an intravenous glucose bolus. Glucose concentrations during the IVGTT were used to calculate the area under the curve of glucose and the clearance rate of glucose. In addition, glucose and insulin data from the IVGTT were fitted in the minimal model to derive the insulin sensitivity parameter, Si. Based on blood samples taken before the start of the IVGTT, basal concentrations of glucose, insulin, NEFA, and β-hydroxybutyrate were determined and used to calculate surrogate indices for insulin sensitivity, such as the homeostasis model of insulin resistance, the quantitative insulin sensitivity check index, the revised quantitative insulin sensitivity check index and the revised quantitative insulin sensitivity check index including β-hydroxybutyrate. Correlation analysis revealed no association between the results obtained by the HEC test and any of the surrogate indices for insulin sensitivity. For the measures derived from the IVGTT, the area under the curve for the first 60 min of the test and the Si derived from the minimal model demonstrated good correlation with the gold standard. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Development of a high-sensitivity and portable cell using Helmholtz resonance for noninvasive blood glucose-level measurement based on photoacoustic spectroscopy.

    Science.gov (United States)

    Tachibana, K; Okada, K; Kobayashi, R; Ishihara, Y

    2016-08-01

    We describe the possibility of high-sensitivity noninvasive blood glucose measurement based on photoacoustic spectroscopy (PAS). The demand for noninvasive blood glucose-level measurement has increased due to the explosive increase in diabetic patients. We have developed a noninvasive blood glucose-level measurement based on PAS. The conventional method uses a straight-type resonant cell. However, the cell volume is large, which results in a low detection sensitivity and difficult portability. In this paper, a small-sized Helmholtz-type resonant cell is proposed to improve detection sensitivity and portability by reducing the cell dead volume. First, the acoustic property of the small-sized Helmholtz-type resonant cell was evaluated by performing an experiment using a silicone rubber. As a result, the detection sensitivity of the small-sized Helmholtz-type resonant cell was approximately two times larger than that of the conventional straight-type resonant cell. In addition, the inside volume was approximately 30 times smaller. Second, the detection limits of glucose concentration were estimated by performing an experiment using glucose solutions. The experimental results showed that a glucose concentration of approximately 1% was detected by the small-sized Helmholtz-type resonant cell. Although these results on the sensitivity of blood glucose-level measurement are currently insufficient, they suggest that miniaturization of a resonance cell is effective in the application of noninvasive blood glucose-level measurement.

  10. Serum bile acids are higher in humans with prior gastric bypass: potential contribution to improved glucose and lipid metabolism

    DEFF Research Database (Denmark)

    Patti, Mary-Elizabeth; Houten, Sander M; Bianco, Antonio C

    2009-01-01

    , glycochenodeoxycholic, and glycodeoxycholic acids were all significantly higher in GB compared to Ov (P glucose (r = -0.59, P triglycerides (r = -0.40, P = 0.05), and positively correlated with adiponectin (r = -0.48, P ... performed cross-sectional analysis of fasting serum bile acid composition and both fasting and post-meal metabolic variables, in three subject groups: (i) post-GB surgery (n = 9), (ii) without GB matched to preoperative BMI of the index cohort (n = 5), and (iii) without GB matched to current BMI...... of the index cohort (n = 10). Total serum bile acid concentrations were higher in GB (8.90 +/- 4.84 micromol/l) than in both overweight (3.59 +/- 1.95, P = 0.005, Ov) and severely obese (3.86 +/- 1.51, P = 0.045, MOb). Bile acid subfractions taurochenodeoxycholic, taurodeoxycholic, glycocholic...

  11. Muscle insulin sensitivity and glucose metabolism are controlled by the intrinsic muscle clock★

    Science.gov (United States)

    Dyar, Kenneth A.; Ciciliot, Stefano; Wright, Lauren E.; Biensø, Rasmus S.; Tagliazucchi, Guidantonio M.; Patel, Vishal R.; Forcato, Mattia; Paz, Marcia I.P.; Gudiksen, Anders; Solagna, Francesca; Albiero, Mattia; Moretti, Irene; Eckel-Mahan, Kristin L.; Baldi, Pierre; Sassone-Corsi, Paolo; Rizzuto, Rosario; Bicciato, Silvio; Pilegaard, Henriette; Blaauw, Bert; Schiaffino, Stefano

    2013-01-01

    Circadian rhythms control metabolism and energy homeostasis, but the role of the skeletal muscle clock has never been explored. We generated conditional and inducible mouse lines with muscle-specific ablation of the core clock gene Bmal1. Skeletal muscles from these mice showed impaired insulin-stimulated glucose uptake with reduced protein levels of GLUT4, the insulin-dependent glucose transporter, and TBC1D1, a Rab-GTPase involved in GLUT4 translocation. Pyruvate dehydrogenase (PDH) activity was also reduced due to altered expression of circadian genes Pdk4 and Pdp1, coding for PDH kinase and phosphatase, respectively. PDH inhibition leads to reduced glucose oxidation and diversion of glycolytic intermediates to alternative metabolic pathways, as revealed by metabolome analysis. The impaired glucose metabolism induced by muscle-specific Bmal1 knockout suggests that a major physiological role of the muscle clock is to prepare for the transition from the rest/fasting phase to the active/feeding phase, when glucose becomes the predominant fuel for skeletal muscle. PMID:24567902

  12. Insulin Sensitivity and Plasma Glucose Response to Aerobic Exercise in Pregnant Women at Risk for Gestational Diabetes Mellitus.

    Science.gov (United States)

    Embaby, Heba; Elsayed, Enas; Fawzy, Mohamed

    2016-09-01

    Gestational diabetes mellitus (GDM) is one of the common complications that occur during pregnancy. Early intervention is essential to prevent the development of the disease in the non-pregnant state but also helpful in preventing the occurrence of GDM. The aim of the study was to assess the effect of aerobic exercises on insulin sensitivity and fasting plasma glucose level in pregnant women with risk for gestational diabetes mellitus. Forty multigravidae women between 20-24 weeks of gestation with risk for GDM were randomly selected (age range was 25-35 years), body mass index ranged from 30-35 kg/m 2 . Women were divided into two equal groups: intervention group (A), which followed an aerobic exercise program in the form of walking on treadmill, three times weekly until the end of 37 weeks of gestation in addition to diet control. Control group (B) which received diet control with usual care given by obstetricians and midwives. Evaluation of the women in both groups was carried out before and after treatment program through assessment of fasting blood glucose and insulin levels. There was a highly statistically significance decrease in fasting blood glucose level, fasting insulin level in both groups where the p value was 0.0001 favoring group (A). Moderate intensity of aerobic exercises were effective in reducing fasting blood glucose level and fasting insulin level in pregnant women with risk for gestational diabetes mellitus.

  13. Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes

    Science.gov (United States)

    Davidson, Matthew D.; Ballinger, Kimberly R.; Khetani, Salman R.

    2016-06-01

    Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations.

  14. Effect of Artemisia dracunculus Administration on Glycemic Control, Insulin Sensitivity, and Insulin Secretion in Patients with Impaired Glucose Tolerance.

    Science.gov (United States)

    Méndez-Del Villar, Miriam; Puebla-Pérez, Ana M; Sánchez-Peña, María J; González-Ortiz, Luis J; Martínez-Abundis, Esperanza; González-Ortiz, Manuel

    2016-05-01

    To evaluate the effect of Artemisia dracunculus on glycemic control, insulin sensitivity, and insulin secretion in patients with impaired glucose tolerance (IGT). A randomized, double blind, placebo-controlled clinical trial was performed in 24 patients with diagnosis of IGT. Before and after the intervention, glucose and insulin levels were measured every 30 min for 2 h after a 75-g dextrose load, along with glycated hemoglobin A1c (A1C) and lipid profile. Twelve patients received A. dracunculus (1000 mg) before breakfast and dinner for 90 days; the remaining 12 patients received placebo. Area under the curve (AUC) of glucose and insulin, total insulin secretion, first phase of insulin secretion, and insulin sensitivity were calculated. Wilcoxon signed-rank, Mann-Whitney U, and chi-square tests were used for statistical analyses. The institutional ethics committee approved the protocol. After A. dracunculus administration, there were significant decreases in systolic blood pressure (SBP; 120.0 ± 11.3 vs. 113.0 ± 11.2 mmHg, P AUC of insulin (56,136.0 ± 27,426.0 vs. 44,472.0 ± 23,370.0 pmol/L, P AUC of insulin, and total insulin secretion with a significant increase in HDL-C levels.

  15. Engineering of Class II Cellobiose Dehydrogenases for Improved Glucose Sensitivity and Reduced Maltose Affinity

    DEFF Research Database (Denmark)

    Ortiz, Roberto; Rahman, Mahbubur; Zangrilli, Beatrice

    2017-01-01

    The front cover artwork is provided by Prof. Lo Gorton from Lund University (Sweden) and his co-workers. The image shows mutated cellobiose dehydrogenase (CDH) immobilized on a graphite electrode and how preferentially glucose is oxidized by this enzyme. Read the full text of the Article at 10.1002...

  16. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

    Science.gov (United States)

    Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the Brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose Homeostasis. The objective of this study was to determine whethe...

  17. The Role of Helicobacter pylori Seropositivity in Insulin Sensitivity, Beta Cell Function, and Abnormal Glucose Tolerance

    Directory of Open Access Journals (Sweden)

    Lou Rose Malamug

    2014-01-01

    Full Text Available Infection, for example, Helicobacter pylori (H. pylori, has been thought to play a role in the pathogenesis of type 2 diabetes mellitus (T2DM. Our aim was to determine the role of H. pylori infection in glucose metabolism in an American cohort. We examined data from 4,136 non-Hispanic white (NHW, non-Hispanic black (NHB, and Mexican Americans (MA aged 18 and over from the NHANES 1999-2000 cohort. We calculated the odds ratios for states of glucose tolerance based on the H. pylori status. We calculated and compared homeostatic model assessment insulin resistance (HOMA-IR and beta cell function (HOMA-B in subjects without diabetes based on the H. pylori status. The results were adjusted for age, body mass index (BMI, poverty index, education, alcohol consumption, tobacco use, and physical activity. The H. pylori status was not a risk factor for abnormal glucose tolerance. After adjustment for age and BMI and also adjustment for all covariates, no difference was found in either HOMA-IR or HOMA-B in all ethnic and gender groups except for a marginally significant difference in HOMA-IR in NHB females. H. pylori infection was not a risk factor for abnormal glucose tolerance, nor plays a major role in insulin resistance or beta cell dysfunction.

  18. A single dual-emissive nanofluorophore test paper for highly sensitive colorimetry-based quantification of blood glucose.

    Science.gov (United States)

    Huang, Xiaoyan; Zhou, Yujie; Liu, Cui; Zhang, Ruilong; Zhang, Liying; Du, Shuhu; Liu, Bianhua; Han, Ming-Yong; Zhang, Zhongping

    2016-12-15

    Fluorescent test papers are promising for the wide applications in the assays of diagnosis, environments and foods, but unlike classical dye-absorption-based pH test paper, they are usually limited in the qualitative yes/no type of detection by fluorescent brightness, and the colorimetry-based quantification remains a challenging task. Here, we report a single dual-emissive nanofluorophore probe to achieve the consecutive color variations from blue to red for the quantification of blood glucose on its as-prepared test papers. Red quantum dots were embedded into silica nanoparticles as a stable internal standard emission, and blue carbon dots (CDs) were further covalently linked onto the surface of silica, in which the ratiometric fluorescence intensity of blue to red is controlled at 5:1. While the oxidation of glucose induced the formation of Fe(3+) ions, the blue emission of CDs was thus quenched by the electron transfer from CDs to Fe(3+), displaying a serial of consecutive color variations from blue to red with the dosage of glucose. The high-quality test papers printed by the probe ink exhibited a dosage-sensitive allochromatic capability with the clear differentiations of ~5, 7, 9, 11mM glucose in human serum (normal: 3-8mM). The blood glucose determined by the test paper was almost in accordance with that measured by a standard glucometer. The method reported here opens a window to the wide applications of fluorescent test paper in biological assays. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Effects of exercise training on glucose control, lipid metabolism, and insulin sensitivity in hypertriglyceridemia and non-insulin dependent diabetes mellitus.

    Science.gov (United States)

    Lampman, R M; Schteingart, D E

    1991-06-01

    Exercise training has potential benefits for patients with hyperlipidemia and/or non-insulin dependent diabetes mellitus. In nondiabetic, nonobese subjects with hypertriglyceridemia, exercise training alone increased insulin sensitivity, improved glucose tolerance, and lowered serum triglyceride and cholesterol levels. These improvements did not occur when exercise training alone was given to similar patients with impaired glucose tolerance. In severely obese (X = 125 kg) subjects without diabetes melitus, a 600 calorie diet alone decreased glucose and insulin concentrations and improved glucose tolerance but did not increase insulin sensitivity. The addition of exercise training improved insulin sensitivity. Obese, non-insulin dependent diabetes mellitus subjects on sulfonylurea therapy alone increased insulin levels but failed to improve insulin sensitivity or glucose levels. In contrast, the addition of exercise training to this medication resulted in improved insulin sensitivity and lowered glucose levels. We conclude that exercise training has major effects on lowering triglyceride levels in hyperlipidemic subjects and can potentiate the effect of diet or drug therapy on glucose metabolism in patients with non-insulin dependent diabetes mellitus.

  20. Gut microbiota metabolites, amino acid metabolites and improvements in insulin sensitivity and glucose metabolism: the POUNDS Lost trial.

    Science.gov (United States)

    Heianza, Yoriko; Sun, Dianjianyi; Li, Xiang; DiDonato, Joseph A; Bray, George A; Sacks, Frank M; Qi, Lu

    2018-06-02

    Alterations in gut microbiota have been linked to host insulin resistance, diabetes and impaired amino acid metabolism. We investigated whether changes in gut microbiota-dependent metabolite of trimethylamine N-oxide (TMAO) and its nutrient precursors (choline and L-carnitine) were associated with improvements in glucose metabolism and diabetes-related amino acids in a weight-loss diet intervention. We included 504 overweight and obese adults who were randomly assigned to one of four energy-reduced diets varying in macronutrient intake. The 6-month changes (Δ) in TMAO, choline and L-carnitine levels after the intervention were calculated. Greater decreases in choline and L-carnitine were significantly (p<0.05) associated with greater improvements in fasting insulin concentrations and homeostasis model assessment of insulin resistance (HOMA-IR) at 6 months. The reduction of choline was significantly related to 2-year improvements in glucose and insulin resistance. We found significant linkages between dietary fat intake and ΔTMAO for changes in fasting glucose, insulin and HOMA-IR (p interaction <0.05); a greater increase in TMAO was related to lesser improvements in the outcomes among participants who consumed a high-fat diet. In addition, ΔL-carnitine and Δcholine were significantly related to changes in amino acids (including branched-chain and aromatic amino acids). Interestingly, the associations of ΔTMAO, Δcholine and ΔL-carnitine with diabetes-related traits were independent of the changes in amino acids. Our findings underscore the importance of changes in TMAO, choline and L-carnitine in improving insulin sensitivity during a weight-loss intervention for obese patients. Dietary fat intake may modify the associations of TMAO with insulin sensitivity and glucose metabolism. NCT00072995. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless

  1. Higher intramuscular triacylglycerol in women does not impair insulin sensitivity and proximal insulin signaling

    DEFF Research Database (Denmark)

    Høeg, Louise; Roepstorff, Carsten; Thiele, Maja

    2009-01-01

    that despite 47% higher IMTG levels in women in the follicular phase whole body as well as leg insulin sensitivity are higher than in matched men. This was not explained by sex differences in proximal insulin signalling in women. In women it seems that a high capillary density and type 1 muscle fiber...... expression may be important for insulin action. Key words: Muscle Triglycerides, gender, insulin action, sex paradox....

  2. Effects of short-term metformin treatment on insulin sensitivity of blood glucose and free fatty acids.

    Science.gov (United States)

    Iannello, S; Camuto, M; Cavaleri, A; Milazzo, P; Pisano, M G; Bellomia, D; Belfiore, F

    2004-01-01

    Based on the known effect of metformin (MET) in improving insulin sensitivity in type 2 diabetes, with the scope to focus the effects on glycaemic and free fatty acids (FFA) levels, we studied the effects of a short-term treatment with this drug in obese subjects and obese patients with diabetes or family history of diabetes (FHD). We used a method to allow us to evaluate the possible difference of insulin sensibility with regard to the insulin action on glycaemia and blood FFA, both in the basal state and during oral glucose tolerance test (OGTT). Insulin sensitivity was investigated before and after MET treatment (850 mg bid for 10 days) in seven obese subjects with normal glucose tolerance and without FHD and 13 obese patients with diabetes (n=7) or FHD (n=6). By using specifically designed formulae, we calculated four insulin-sensitivity indices (ISI) from basal level (b) and area values (a) (during OGTT) of insulinaemia, glycaemia (gly) or FFA (ffa), namely: ISI (gly)-b, ISI (gly)-a, ISI (ffa)-b and ISI (ffa)-a. In patients with diabetes or FHD, MET improved ISI (gly)-b (0.79 +/- 0.06 vs. 0.59 +/- 0.07, p<0.001) and ISI (gly)-a (0.69 +/- 0.09 vs. 0.51 +/- 0.07, p<0.05), whereas only minor changes occurred for ISI (ffa)-b and ISI (ffa)-a. In contrast, in simple obese subjects, MET induced further deterioration of both ISI (gly)-a (0.47 +/- 0.07 vs. 0.64 +/- 0.10, p<0.01) and ISI (ffa)-a (0.43 +/- 0.07 vs. 0.55 +/- 0.08, p<0.05). Fasting level and total area of lactate were high in the obese patients and were not affected by MET. A statistically significant increase (p<0.01), however, was observed for the 'decremental' area of lactate in obese subjects with diabetes or FHD, which might probably contribute to the reduction of insulin resistance induced by the drug in these patients. Although the low number of subjects studied precludes absolute conclusions, data would suggest that MET improved ISI towards glucose but not towards FFA, in the diabetic and

  3. Impaired beta cell sensitivity to incretins in type 2 diabetes is insufficiently compensated by higher incretin response

    DEFF Research Database (Denmark)

    Tura, A.; Bagger, J. I.; Ferrannini, E.

    2017-01-01

    Background and aims The incretin effect is impaired in type 2 diabetes (T2D), but the underlying mechanisms are only partially understood. We investigated the relationships between the time course of the incretin effect and that of glucose-dependent insulinotropic polypeptide (GIP) and glucagon......-like peptide-1 (GLP-1) during oral glucose tolerance tests (OGTTs), thereby estimating incretin sensitivity of the beta cell, and its associated factors. Methods and results Eight patients with T2D and eight matched subjects with normal glucose tolerance (NGT) received 25, 75, and 125 g OGTTs and corresponding...... was correlated with that of both GIP and GLP-1 in each subject (median r = 0.67 in NGT and 0.45 in T2D). We calculated an individual beta cell sensitivity to incretins (SINCR) using a weighted average of GIP and GLP-1 (pooled incretin concentration, PIC), as the slope of the relationship between PINCR and PIC...

  4. The Need for Context-Sensitive Measures of Educational Quality in Transnational Higher Education

    Science.gov (United States)

    Pyvis, David

    2011-01-01

    This paper argues that the current approach to educational quality formation in transnational higher education promotes educational imperialism, and that guidelines and practices should be altered to embrace context-sensitive measures of quality. The claims are sustained by findings from a study that investigated how academics understood and…

  5. Comparison of surrogate indices for insulin sensitivity with parameters of the intravenous glucose tolerance test in early lactation dairy cattle.

    Science.gov (United States)

    Alves-Nores, V; Castillo, C; Hernandez, J; Abuelo, A

    2017-10-01

    The aim of this study was to investigate the correlation between different surrogate indices and parameters of the intravenous glucose tolerance test (IVGTT) in dairy cows at the start of their lactation. Ten dairy cows underwent IVGTT on Days 3 to 7 after calving. Areas under the curve during the 90 min after infusion, peak and nadir concentrations, elimination rates, and times to reach half-maximal and basal concentrations for glucose, insulin, nonesterified fatty acids, and β-hydroxybutyrate were calculated. Surrogate indices were computed using the average of the IVGTT basal samples, and their correlation with the IVGTT parameters studied through the Spearman's rank test. No statistically significant or strong correlation coefficients (P > 0.05; |ρ| insulin sensitivity measures derived from the IVGTT and any of the surrogate indices. Therefore, these results support that the assessment of insulin sensitivity in early lactation cattle cannot rely on the calculation of surrogate indices in just a blood sample, and the more laborious tests (ie, hyperinsulinemic euglycemic clamp test or IVGTT) should be employed to predict the sensitivity of the peripheral tissues to insulin accurately. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Engineering of Cellobiose Dehydrogenases for Improved Glucose Sensitivity and Reduced Maltose Affinity

    DEFF Research Database (Denmark)

    Ortiz, Roberto; Rahman, Mahbubur; Zangrilli, Beatrice

    2017-01-01

    Cellobiose dehydrogenase (CDH) is a fungal extracellular flavocytochrome capable of direct electron transfer (DET). Unlike other CDHs, the pH optimum for CDHs from Corynascus thermophilus (CtCDH) and Humicola insolens (HiCDH) is close to the human physiological pH in blood (7.4). These are......, therefore, interesting candidates for glucose measurements in human blood and the application in enzymatic fuel cells is, however, limited by their relatively low activity with this substrate. In this work, the substrate specificities of CtCDH and HiCDH have been altered by a single cysteine to tyrosine...... substitution in the active sites of CtCDH (position 291) and HiCDH (position 285), which resulted in improved kinetic constants with glucose while decreasing the activity with several disaccharides, including maltose. The DET properties of the generated CDH variants were tested in the absence...

  7. Nitrogen-Doped Carbon Dots as A New Substrate for Sensitive Glucose Determination

    Directory of Open Access Journals (Sweden)

    Hanxu Ji

    2016-05-01

    Full Text Available Nitrogen-doped carbon dots are introduced as a novel substrate suitable for enzyme immobilization in electrochemical detection metods. Nitrogen-doped carbon dots are easily synthesised from polyacrylamide in just one step. With the help of the amino group on chitosan, glucose oxidase is immobilized on nitrogen-doped carbon dots-modified carbon glassy electrodes by amino-carboxyl reactions. The nitrogen-induced charge delocalization at nitrogen-doped carbon dots can enhance the electrocatalytic activity toward the reduction of O2. The specific amino-carboxyl reaction provides strong and stable immobilization of GOx on electrodes. The developed biosensor responds efficiently to the presence of glucose in serum samples over the concentration range from 1 to 12 mM with a detection limit of 0.25 mM. This novel biosensor has good reproducibility and stability, and is highly selective for glucose determination under physiological conditions. These results indicate that N-doped quantum dots represent a novel candidate material for the construction of electrochemical biosensors.

  8. Metformin improves glucose effectiveness, not insulin sensitivity: predicting treatment response in women with polycystic ovary syndrome in an open-label, interventional study.

    Science.gov (United States)

    Pau, Cindy T; Keefe, Candace; Duran, Jessica; Welt, Corrine K

    2014-05-01

    Although metformin is widely used to improve insulin resistance in women with polycystic ovary syndrome (PCOS), its mechanism of action is complex, with inconsistent effects on insulin sensitivity and variability in treatment response. The aim of the study was to delineate the effect of metformin on glucose and insulin parameters, determine additional treatment outcomes, and predict patients with PCOS who will respond to treatment. We conducted an open-label, interventional study at an academic medical center. Women with PCOS (n = 36) diagnosed by the National Institutes of Health criteria participated in the study. Subjects underwent fasting blood sampling, an IV glucose tolerance test, dual-energy x-ray absorptiometry scan, transvaginal ultrasound, and measurement of human chorionic gonadotropin-stimulated androgen levels before and after 12 weeks of treatment with metformin extended release 1500 mg/d. Interval visits were performed to monitor anthropometric measurements and menstrual cycle parameters. Changes in glucose and insulin parameters, androgen levels, anthropometric measurements, and ovulatory menstrual cycles were evaluated. Insulin sensitivity did not change despite weight loss. Glucose effectiveness (P = .002) and the acute insulin response to glucose (P = .002) increased, and basal glucose levels (P = .001) decreased after metformin treatment. T levels also decreased. Women with improved ovulatory function (61%) had lower baseline T levels and lower baseline and stimulated T and androstenedione levels after metformin treatment (all P effectiveness and insulin sensitivity, metformin does not improve insulin sensitivity in women with PCOS but does improve glucose effectiveness. The improvement in glucose effectiveness may be partially mediated by decreased glucose levels. T levels also decreased with metformin treatment. Ovulation during metformin treatment was associated with lower baseline T levels and greater T and androstenedione decreases during

  9. Postprandial changes in glucose oxidation and insulin sensitivity in metabolic syndrome: Influence of fibroblast growth factor 21 and vitamin D status.

    Science.gov (United States)

    Pathak, Kaveri; Soares, Mario J; Zhao, Yun; James, Anthony P; Sherriff, Jillian L; Newsholme, Philip

    2017-05-01

    Metabolic inflexibility due to insulin resistance has been reported in metabolic syndrome (MetS). Fibroblast growth factor 21 (FGF21) and vitamin D status may improve insulin sensitivity. The aim of this study was to investigate glucose-induced thermogenesis and oxidation in MetS, and to examine whether changes in FGF21 or prevailing vitamin D status modulated defined metabolic parameters. Forty-eight overweight and obese older adults (14 men, 34 women; ages 51 ± 15 y) were studied. Resting metabolic rate (RMR) and respiratory quotient (RQ) were measured before and intermittently for 2 h after an oral glucose tolerance test (OGTT). The total area under the curve (TAUC) was calculated. Insulin sensitivity index (ISI) was determined as 10 4 /(insulin × glucose) for fasting and 2 h venous blood. Fat mass (FM) and fat free mass (FFM) were measured by dual-energy x-ray absorptiometry. Participants were grouped by metabolic syndrome (MetS+ for disease presence; MetS- when no disease was present) and by median 25 hydroxyvitamin D (OHD) concentration as VD_low and VD_high. 25 OHD was also tested as a continuous variable. A parsimonious 2 × 2 analysis of variance included age, FM, FFM and MetS × sex interaction. Adjusted RMR was similar between groups but an interactive effect of MetS and sex was noted. Fasting RQ was significantly different between vitamin groups (VD_low: 0.835 ± 0.008 versus VD_high: 0.810 ± 0.008; P = 0.024) and fasting ISI was significantly greater in MetS- compared with MetS+ (P = 0.037). Postglucose increases in thermogenesis, RQ, and FGF21 were significant, but ISI decreased. Adjusted postprandial TAUC_RQ (VD_low: 1.71 ± 0.01; VD_high: 1.74 ± 0.001; P = 0.041) and ISI_2 h (VD_low: 35.41 ± 0.21; VD_high: 101.90 ± 0.21; P = 0.001) were significantly different. Adjusted FGF21 was similar across all comparisons before and after OGTT. Higher vitamin D status, but not FGF21, was associated with greater postprandial

  10. DNA-dispersed graphene/NiO hybrid materials for highly sensitive non-enzymatic glucose sensor

    International Nuclear Information System (INIS)

    Lv Wei; Jin Fengmin; Guo Quangui; Yang Quanhong; Kang Feiyu

    2012-01-01

    Highlights: ► We investigated the potential of GNS/NiO/DNA hybrid used as a nonenzymatic sensor. ► DNA is a highly efficient disperse agent for GNS/NiO hybrid than ionic surfactants. ► GNS/NiO/DNA hybrid shows fast electron transfer in the electrochemical reaction. ► GNS/NiO/DNA hybrid shows good detection performance towards glucose. - Abstract: We demonstrate graphene nanosheet/NiO hybrids (GNS/NiO) as the active material for high-performance non-enzymatic glucose sensors. Such sensors are fabricated by DNA-dispersed GNS/NiO suspension deposited on glassy carbon electrodes. ss-DNA shows strong dispersing ability for the GNS/NiO hybrid materials resulting in stable water-dispersible GNS/NiO/DNA hybrids with fully separated layers. The GNS/NiO/DNA hybrids show enhanced electron transfer in the electrocatalytic reaction process, and accordingly, such hybrids modified electrodes show good sensing performance towards glucose and are characterized by large detection ranges, short response periods, low detection limit and high sensitivity and stability.

  11. Imaging of a glucose analog, calcium and NADH in neurons and astrocytes: dynamic responses to depolarization and sensitivity to pioglitazone

    Science.gov (United States)

    Pancani, Tristano; Anderson, Katie L.; Porter, Nada M.; Thibault, Olivier

    2011-01-01

    Neuronal Ca2+ dyshomeostasis associated with cognitive impairment and mediated by changes in several Ca2+ sources has been seen in animal models of both aging and diabetes. In the periphery, dysregulation of intracellular Ca2+ signals may contribute to the development of insulin resistance. In the brain, while it is well-established that type 2 diabetes mellitus is a risk factor for the development of dementia in the elderly, it is not clear whether Ca2+ dysregulation might also affect insulin sensitivity and glucose utilization. Here we present a combination of imaging techniques testing the disappearance of the fluorescent glucose analog 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) as an indication of glycolytic activity in neurons and astrocytes. Our work shows that glucose utilization at rest is greater in neurons compared to astrocytes, and ceases upon activation in neurons with little change in astrocytes. Pretreatment of hippocampal cultures with pioglitazone, a drug used in the treatment of type 2 diabetes, significantly reduced glycolytic activity in neurons and enhanced it in astrocytes. This series of experiments, including FURA-2 and NADH imaging, provides results that are consistent with the idea that Ca2+ levels may rapidly alter glycolytic activity, and that downstream events beyond Ca2+ dysregulation with aging, may alter cellular metabolism in the brain. PMID:21978418

  12. Fabrication of gallium hexacyanoferrate modified carbon ionic liquid paste electrode for sensitive determination of hydrogen peroxide and glucose

    Energy Technology Data Exchange (ETDEWEB)

    Haghighi, Behzad, E-mail: haghighi@iasbs.ac.ir; Khosravi, Mehdi; Barati, Ali

    2014-07-01

    Gallium hexacyanoferrate (GaHCFe) and graphite powder were homogeneously dispersed into n-dodecylpyridinium hexafluorophosphate and paraffin to fabricate GaHCFe modified carbon ionic liquid paste electrode (CILPE). Mixture experimental design was employed to optimize the fabrication of GaHCFe modified CILPE (GaHCFe-CILPE). A pair of well-defined redox peaks due to the redox reaction of GaHCFe through one-electron process was observed for the fabricated electrode. The fabricated GaHCFe-CILPE exhibited good electrocatalytic activity towards reduction and oxidation of H{sub 2}O{sub 2}. The observed sensitivities for the electrocatalytic oxidation and reduction of H{sub 2}O{sub 2} at the operating potentials of + 0.8 and − 0.2 V were about 13.8 and 18.3 mA M{sup −1}, respectively. The detection limit (S/N = 3) for H{sub 2}O{sub 2} was about 1 μM. Additionally, glucose oxidase (GOx) was immobilized on GaHCFe-CILPE using two methodology, entrapment into Nafion matrix and cross-linking with glutaraldehyde and bovine serum albumin, in order to fabricate glucose biosensor. Linear dynamic rage, sensitivity and detection limit for glucose obtained by the biosensor fabricated using cross-linking methodology were 0.1–6 mM, 0.87 mA M{sup −1} and 30 μM, respectively and better than those obtained (0.2–6 mM, 0.12 mA M{sup −1} and 50 μM) for the biosensor fabricated using entrapment methodology. - Highlights: • Gallium hexacyanoferrate modified carbon ionic liquid paste electrode was fabricated. • Mixture experimental design was used to optimize electrode fabrication. • Response trace plot was used to show the effect of electrode materials on response. • The sensor exhibited electrocatalytic activity towards H{sub 2}O{sub 2} reduction and oxidation. • Glucose biosensor was fabricated by immobilization of glucose oxidase on sensor.

  13. Thiolate-Capped CdSe/ZnS Core-Shell Quantum Dots for the Sensitive Detection of Glucose

    Directory of Open Access Journals (Sweden)

    Samsulida Abd. Rahman

    2017-07-01

    Full Text Available A semiconducting water-soluble core-shell quantum dots (QDs system capped with thiolated ligand was used in this study for the sensitive detection of glucose in aqueous samples. The QDs selected are of CdSe-coated ZnS and were prepared in house based on a hot injection technique. The formation of ZnS shell at the outer surface of CdSe core was made via a specific process namely, SILAR (successive ionic layer adsorption and reaction. The distribution, morphology, and optical characteristics of the prepared core-shell QDs were assessed by transmission electron microscopy (TEM and spectrofluorescence, respectively. From the analysis, the results show that the mean particle size of prepared QDs is in the range of 10–12 nm and that the optimum emission condition was displayed at 620 nm. Further, the prepared CdSe/ZnS core shell QDs were modified by means of a room temperature ligand-exchange method that involves six organic ligands, L-cysteine, L-histidine, thio-glycolic acid (TGA or mercapto-acetic acid, MAA, mercapto-propionic acid (MPA, mercapto-succinic acid (MSA, and mercapto-undecanoic acid (MUA. This process was chosen in order to maintain a very dense water solubilizing environment around the QDs surface. From the analysis, the results show that the CdSe/ZnS capped with TGA (CdSe/ZnS-TGA exhibited the strongest fluorescence emission as compared to others; hence, it was tested further for the glucose detection after their treatment with glucose oxidase (GOx and horseradish peroxidase (HRP enzymes. Here in this study, the glucose detection is based on the fluorescence quenching effect of the QDs, which is correlated to the oxidative reactions occurred between the conjugated enzymes and glucose. From the analysis of results, it can be inferred that the resultant GOx:HRP/CdSe/ZnS-TGA QDs system can be a suitable platform for the fluorescence-based determination of glucose in the real samples.

  14. Preserved glucagon-like peptide-1 responses to oral glucose, but reduced incretin effect, insulin secretion and sensitivity in young Asians with type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Yeow, Toh Peng; Pacini, Giovanni; Tura, Andrea

    2017-01-01

    are scarce. We examined the insulin resistance, β-cell function (BC), glucagon-like peptide (GLP)-1 hormone and incretin effect in Asian YT2DM. RESEARCH DESIGN AND METHODS: This case-control study recruited 25 Asian YT2DM and 15 healthy controls, matched for gender, ethnicity and body mass index. Serum......OBJECTIVE: Youth onset type 2 diabetes mellitus (YT2DM) is a globally rising phenomenon with substantial Asians representation. The understanding of its pathophysiology is derived largely from studies in the obese African-American and Caucasian populations, while studies on incretin effect...... glucose, insulin, C peptide and GLP-1 were sampled during 2-hour oral glucose tolerance tests (OGTTs) and 1-hour intravenous glucose tolerance tests (IVGTTs). Insulin sensitivity was derived from the Quantitative Insulin Sensitivity Check Index (QUICKI), Oral Glucose Insulin Sensitivity Index (OGIS...

  15. A higher-complex carbohydrate diet in gestational diabetes mellitus achieves glucose targets and lowers postprandial lipids: a randomized crossover study.

    Science.gov (United States)

    Hernandez, Teri L; Van Pelt, Rachael E; Anderson, Molly A; Daniels, Linda J; West, Nancy A; Donahoo, William T; Friedman, Jacob E; Barbour, Linda A

    2014-01-01

    The conventional diet approach to gestational diabetes mellitus (GDM) advocates carbohydrate restriction, resulting in higher fat (HF), also a substrate for fetal fat accretion and associated with maternal insulin resistance. Consequently, there is no consensus about the ideal GDM diet. We hypothesized that, compared with a conventional, lower-carbohydrate/HF diet (40% carbohydrate/45% fat/15% protein), consumption of a higher-complex carbohydrate (HCC)/lower-fat (LF) Choosing Healthy Options in Carbohydrate Energy (CHOICE) diet (60/25/15%) would result in 24-h glucose area under the curve (AUC) profiles within therapeutic targets and lower postprandial lipids. Using a randomized, crossover design, we provided 16 GDM women (BMI 34 ± 1 kg/m2) with two 3-day isocaloric diets at 31 ± 0.5 weeks (washout between diets) and performed continuous glucose monitoring. On day 4 of each diet, we determined postprandial (5 h) glucose, insulin, triglycerides (TGs), and free fatty acids (FFAs) following a controlled breakfast meal. There were no between-diet differences for fasting or mean nocturnal glucose, but 24-h AUC was slightly higher (∼6%) on the HCC/LF CHOICE diet (P = 0.02). The continuous glucose monitoring system (CGMS) revealed modestly higher 1- and 2-h postprandial glucose on CHOICE (1 h, 115 ± 2 vs. 107 ± 3 mg/dL, P ≤ 0.01; 2 h, 106 ± 3 vs. 97 ± 3 mg/dL, P = 0.001) but well below current targets. After breakfast, 5-h glucose and insulin AUCs were slightly higher (P diet. This highly controlled study randomizing isocaloric diets and using a CGMS is the first to show that liberalizing complex carbohydrates and reducing fat still achieved glycemia below current treatment targets and lower postprandial FFAs. This diet strategy may have important implications for preventing macrosomia.

  16. Highly sensitive colorimetric detection of glucose in a serum based on DNA-embeded Au@Ag core–shell nanoparticles

    International Nuclear Information System (INIS)

    Kang, Fei; Xu, Kun; Hou, Xiangshu

    2015-01-01

    Glucose is a key energy substance in diverse biology and closely related to the life activities of the organism. To develop a simple and sensitive method for glucose detection is extremely urgent but still remains a key challenge. Herein, we report a colorimetric glucose sensor in a homogeneous system based on DNA-embedded core–shell Au@Ag nanoparticles. In this assay, a glucose substrate was first catalytically oxidized by glucose oxidase to produce H 2 O 2 which would further oxidize and gradually etch the outer silver shell of Au@Ag nanoparticles. Afterwards, the solution color changed from yellow to red and the surface plasmon resonance (SPR) band of Au@Ag nanoparticles declined and red-shifted from 430 to 516 nm. Compared with previous silver-based glucose colorimetric detection strategies, the distinctive SPR band change is superior to the color variation, which is critical to the high sensitivity of this assay. Benefiting from the outstanding optical property, robust stability and well-dispersion of the core–shell Au@AgNPs hybrid, this colorimetric assay obtained a detection limit of glucose as low as 10 nM, which is at least a 10-fold improvement over other AgNPs-based procedures. Moreover, this optical biosensor was successfully employed to the determination of glucose in fetal bovine serum. (paper)

  17. Obese Neuronal PPARγ Knockout Mice Are Leptin Sensitive but Show Impaired Glucose Tolerance and Fertility.

    Science.gov (United States)

    Fernandez, Marina O; Sharma, Shweta; Kim, Sun; Rickert, Emily; Hsueh, Katherine; Hwang, Vicky; Olefsky, Jerrold M; Webster, Nicholas J G

    2017-01-01

    The peroxisome-proliferator activated receptor γ (PPARγ) is expressed in the hypothalamus in areas involved in energy homeostasis and glucose metabolism. In this study, we created a deletion of PPARγ brain-knockout (BKO) in mature neurons in female mice to investigate its involvement in metabolism and reproduction. We observed that there was no difference in age at puberty onset between female BKOs and littermate controls, but the BKOs gave smaller litters when mated and fewer oocytes when ovulated. The female BKO mice had regular cycles but showed an increase in the number of cycles with prolonged estrus. The mice also had increased luteinizing hormone (LH) levels during the LH surge and histological examination showed hemorrhagic corpora lutea. The mice were challenged with a 60% high-fat diet (HFD). Metabolically, the female BKO mice showed normal body weight, glucose and insulin tolerance, and leptin levels but were protected from obesity-induced leptin resistance. The neuronal knockout also prevented the reduction in estrous cycles due to the HFD. Examination of ovarian histology showed a decrease in the number of primary and secondary follicles in both genotypes due to the HFD, but the BKO ovaries showed an increase in the number of hemorrhagic follicles. In summary, our results show that neuronal PPARγ is required for optimal female fertility but is also involved in the adverse effects of diet-induced obesity by creating leptin resistance potentially through induction of the repressor Socs3. Copyright © 2017 by the Endocrine Society.

  18. Serum Bile Acids Are Higher in Humans With Prior Gastric Bypass: Potential Contribution to Improved Glucose and Lipid Metabolism

    Science.gov (United States)

    Patti, Mary-Elizabeth; Houten, Sander M.; Bianco, Antonio C.; Bernier, Raquel; Larsen, P. Reed; Holst, Jens J.; Badman, Michael K.; Maratos-Flier, Eleftheria; Mun, Edward C.; Pihlajamaki, Jussi; Auwerx, Johan; Goldfine, Allison B.

    2015-01-01

    The multifactorial mechanisms promoting weight loss and improved metabolism following Roux-en-Y gastric bypass (GB) surgery remain incompletely understood. Recent rodent studies suggest that bile acids can mediate energy homeostasis by activating the G-protein coupled receptor TGR5 and the type 2 thyroid hormone deiodinase. Altered gastrointestinal anatomy following GB could affect enterohepatic recirculation of bile acids. We assessed whether circulating bile acid concentrations differ in patients who previously underwent GB, which might then contribute to improved metabolic homeostasis. We performed cross-sectional analysis of fasting serum bile acid composition and both fasting and post-meal metabolic variables, in three subject groups: (i) post-GB surgery (n = 9), (ii) without GB matched to preoperative BMI of the index cohort (n = 5), and (iii) without GB matched to current BMI of the index cohort (n = 10). Total serum bile acid concentrations were higher in GB (8.90 ± 4.84 µmol/l) than in both overweight (3.59 ± 1.95, P = 0.005, Ov) and severely obese (3.86 ± 1.51, P = 0.045, MOb). Bile acid subfractions taurochenodeoxycholic, taurodeoxycholic, glycocholic, glycochenodeoxycholic, and glycodeoxycholic acids were all significantly higher in GB compared to Ov (P fasting triglycerides (r = −0.40, P = 0.05), and positively correlated with adiponectin (r = −0.48, P < 0.02) and peak glucagon-like peptide-1 (GLP-1) (r = 0.58, P < 0.003). Total bile acids strongly correlated inversely with thyrotropic hormone (TSH) (r = −0.57, P = 0.004). Together, our data suggest that altered bile acid levels and composition may contribute to improved glucose and lipid metabolism in patients who have had GB. PMID:19360006

  19. Insulin sensitivity, insulin release and glucagon-like peptide-1 levels in persons with impaired fasting glucose and/or impaired glucose tolerance in the EUGENE2 study

    DEFF Research Database (Denmark)

    Laakso, M; Zilinskaite, J; Hansen, T

    2008-01-01

    AIMS/HYPOTHESIS: We examined the phenotype of individuals with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) with regard to insulin release and insulin resistance. METHODS: Non-diabetic offspring (n=874; mean age 40+/-10.4 years; BMI 26.6+/-4.9 kg/m(2)) of type 2 diabetic...

  20. A chemo-electro-mechanical model for simulation of responsive deformation of glucose-sensitive hydrogels with the effect of enzyme catalysis

    Science.gov (United States)

    Li, Hua; Luo, Rongmo; Birgersson, Erik; Lam, Khin Yong

    2009-02-01

    A multi-effect-coupling glucose-stimulus (MECglu) model is developed and solved numerically for the swelling behavior of soft smart hydrogels responding to changes in the environmental glucose concentration. The model considers the effect of the glucose oxidation reaction catalyzed by enzymes including glucose oxidase and catalase. It is composed of the Nernst-Planck equation for the mobile species in the solvent, the Poisson equation for the electric potential, and a nonlinear mechanical equation for the large deformations of the hydrogel that arise due to the conversion of chemical energy to mechanical. Based on the theory of the chemo-electro-mechanical-coupled fields, the formulation of the fixed charge groups bound onto the cross-linked polymer network is associated with the change of the ambient solution pH. The MECglu model is validated by comparison between the steady-state computation and experimental equilibrium swelling curves, and good agreement is obtained. A parameter study is then conducted by steady-state simulations to ascertain the impact of various solvent parameters on the responsive swelling behavior of the hydrogel. One key parameter is the glucose concentration, which is varied within the range of practical physiological glucose concentrations from 0 to 16.5 mM (300 mg/ml) to support the design and optimization of an insulin delivery system based on a glucose-sensitive hydrogel with immobilized glucose oxidase and catalase. The influence of oxygen and glucose concentrations in the solvent is then further studied for the distributive profiles of reacting and diffusive species concentrations, the electric potential, the displacement, as well as the swelling ratio of the glucose-sensitive hydrogel.

  1. Sensitive Fluorescent Sensor for Recognition of HIV-1 dsDNA by Using Glucose Oxidase and Triplex DNA

    Directory of Open Access Journals (Sweden)

    Yubin Li

    2018-01-01

    Full Text Available A sensitive fluorescent sensor for sequence-specific recognition of double-stranded DNA (dsDNA was developed on the surface of silver-coated glass slide (SCGS. Oligonucleotide-1 (Oligo-1 was designed to assemble on the surface of SCGS and act as capture DNA, and oligonucleotide-2 (Oligo-2 was designed as signal DNA. Upon addition of target HIV-1 dsDNA (Oligo-3•Oligo-4, signal DNA could bind on the surface of silver-coated glass because of the formation of C•GoC in parallel triplex DNA structure. Biotin-labeled glucose oxidase (biotin-GOx could bind to signal DNA through the specific interaction of biotin-streptavidin, thereby GOx was attached to the surface of SCGS, which was dependent on the concentration of target HIV-1 dsDNA. GOx could catalyze the oxidation of glucose and yield H2O2, and the HPPA can be oxidized into a fluorescent product in the presence of HRP. Therefore, the concentration of target HIV-1 dsDNA could be estimated with fluorescence intensity. Under the optimum conditions, the fluorescence intensity was proportional to the concentration of target HIV-1 dsDNA over the range of 10 pM to 1000 pM, the detection limit was 3 pM. Moreover, the sensor had good sequence selectivity and practicability and might be applied for the diagnosis of HIV disease in the future.

  2. PTP1B antisense oligonucleotide lowers PTP1B protein, normalizes blood glucose, and improves insulin sensitivity in diabetic mice

    Science.gov (United States)

    Zinker, Bradley A.; Rondinone, Cristina M.; Trevillyan, James M.; Gum, Rebecca J.; Clampit, Jill E.; Waring, Jeffrey F.; Xie, Nancy; Wilcox, Denise; Jacobson, Peer; Frost, Leigh; Kroeger, Paul E.; Reilly, Regina M.; Koterski, Sandra; Opgenorth, Terry J.; Ulrich, Roger G.; Crosby, Seth; Butler, Madeline; Murray, Susan F.; McKay, Robert A.; Bhanot, Sanjay; Monia, Brett P.; Jirousek, Michael R.

    2002-01-01

    The role of protein-tyrosine phosphatase 1B (PTP1B) in diabetes was investigated using an antisense oligonucleotide in ob/ob and db/db mice. PTP1B antisense oligonucleotide treatment normalized plasma glucose levels, postprandial glucose excursion, and HbA1C. Hyperinsulinemia was also reduced with improved insulin sensitivity. PTP1B protein and mRNA were reduced in liver and fat with no effect in skeletal muscle. Insulin signaling proteins, insulin receptor substrate 2 and phosphatidylinositol 3 (PI3)-kinase regulatory subunit p50α, were increased and PI3-kinase p85α expression was decreased in liver and fat. These changes in protein expression correlated with increased insulin-stimulated protein kinase B phosphorylation. The expression of liver gluconeogenic enzymes, phosphoenolpyruvate carboxykinase, and fructose-1,6-bisphosphatase was also down-regulated. These findings suggest that PTP1B modulates insulin signaling in liver and fat, and that therapeutic modalities targeting PTP1B inhibition may have clinical benefit in type 2 diabetes. PMID:12169659

  3. Female-Specific Glucose Sensitivity of GnRH1 Neurons Leads to Sexually Dimorphic Inhibition of Reproduction in Medaka.

    Science.gov (United States)

    Hasebe, Masaharu; Kanda, Shinji; Oka, Yoshitaka

    2016-11-01

    Close interaction exists between energy-consuming reproduction and nutritional status. However, there are differences in costs and priority for reproduction among species and even between sexes, which leads to diversification of interactions between reproduction and nutritional status. Despite such diversified interactions among species and sexes, most of the analysis of the nutritional status-dependent regulation of reproduction has been limited to an endothermic vertebrate, mammalian species of either sex. Therefore, the mechanisms underlying the diversified interactions remain elusive. In the present study, we demonstrated the effects of malnutritional status on reproduction at both organismal and cellular levels in an ectothermic vertebrate, a teleost medaka of both sexes. First, we analyzed the effects of malnutrition by fasting on gonadosomatic index, number of spawned/fertilized eggs, and courtship behavior. Fasting strongly suppressed reproduction in females but, surprisingly, not in males. Next, we analyzed the effects of fasting on firing activity of hypothalamic GnRH1 neurons, which form the final common pathway for the control of reproduction. An electrophysiological analysis showed that low glucose, which is induced by fasting, directly suppresses the firing activity of GnRH1 neurons specifically in females through intracellular ATP-sensitive potassium channels and AMP-activated protein kinase pathways. Based on the fact that such suppressions occurred only in females, we conclude that nutritional status-dependent, glucose-sensing in GnRH1 neurons may contribute to the most fitted reproductive regulation for each sex.

  4. Systematic review of randomised controlled trials of the effects of caffeine or caffeinated drinks on blood glucose concentrations and insulin sensitivity in people with diabetes mellitus.

    Science.gov (United States)

    Whitehead, N; White, H

    2013-04-01

    Compounds other than macronutrients have been shown to influence blood glucose concentrations and insulin sensitivity in people with diabetes, with caffeine being one such substance. The present study systematically reviewed the evidence of the effects of caffeine on blood glucose concentrations and/or insulin sensitivity in people with diabetes. Four databases, including MEDLINE and EMBASE, were searched up to 1 February 2012. Randomised controlled trials (RCTs) investigating the effects of caffeine on blood glucose and/or insulin sensitivity in humans, diagnosed with type I, type II or gestational diabetes mellitus (GDM), were included. Quality assessment and data extraction were conducted and agreed by both authors. Of 253 articles retrieved, nine trials (134 participants) were identified. Trials in people with type II diabetes demonstrated that the ingestion of caffeine (approximately 200-500 mg) significantly increased blood glucose concentrations by 16-28% of the area under the curve (AUC) and insulin concentrations by 19-48% of the AUC when taken prior to a glucose load, at the same time as decreasing insulin sensitivity by 14-37%. In type I diabetes, trials indicated enhanced recognition and a reduced duration of hypoglycaemic episodes following ingestion of 400-500 mg caffeine, without altering glycated haemoglobin. In GDM, a single trial demonstrated that approximately 200 mg of caffeine induced a decrease in insulin sensitivity by 18% and a subsequent increase in blood glucose concentrations by 19% of the AUC. Evidence indicates a negative effect of caffeine intake on blood glucose control in individuals with type II diabetes, as replicated in a single trial in GDM. Larger-scale RCTs of longer duration are needed to determine the effects of timing and dose. Early indications of a reduced duration and an improved awareness of hypoglycaemia in type I diabetes require further confirmation. © 2013 The Authors Journal of Human Nutrition and Dietetics

  5. Higher glucose level and systemic oxidative stress decrease the mean velocity index of the retinal artery during flickering light stimulation in type 1 diabetes.

    Science.gov (United States)

    Debelić, Vladimir; Drnovšek Olup, Brigita; Žižek, Bogomir; Skitek, Milan; Jerin, Aleš

    2016-10-31

    To determine whether higher glucose level and systemic oxidative stress decrease mean velocity (MV) index of the central retinal artery (CRA) during flickering light stimulation in type 1 diabetes (T1D). The study was performed in the period from 2008 to 2015 at the University Eye Clinic in Ljubljana. 41 patients with T1D and 37 participants without diabetes were included. MV in the CRA was measured using Doppler ultrasound diagnostics in basal conditions and during 8 Hz flickering light irritation. The plasma levels of glucose, fructosamine, 8-hydroxy-2'-deoxyguanosine (8-OHdG), triglycerides, cholesterol, and low-density lipoprotein (LDL) were measured. Patients with T1D had significantly higher levels of blood glucose (Ptriglycerides (P=0.108), cholesterol (P=0.531), and LDL (P=0.645) between the groups. Patients with T1D also had a significantly lower MV index in the CRA (1.11±0.15 vs 1.24±0.23; P=0.010). In the T1D group, a significant negative correlation was found between the level of glucose (r=0.58; Pindex in the CRA. At the same time, in this group fructosamine and 8-OHdG levels had a separate effect on the MV index (adjusted R2=0.38, Pglucose levels, the medium-term glucose level, and systemic oxidative stress could importantly reduce retinal vasodilatation during flickering light irritation in patients with T1D.

  6. Adult-onset obesity reveals prenatal programming of glucose-insulin sensitivity in male sheep nutrient restricted during late gestation.

    Directory of Open Access Journals (Sweden)

    Philip Rhodes

    Full Text Available BACKGROUND: Obesity invokes a range of metabolic disturbances, but the transition from a poor to excessive nutritional environment may exacerbate adult metabolic dysfunction. The current study investigated global maternal nutrient restriction during early or late gestation on glucose tolerance and insulin sensitivity in the adult offspring when lean and obese. METHODS/PRINCIPAL FINDINGS: Pregnant sheep received adequate (1.0M; CE, n = 6 or energy restricted (0.7M diet during early (1-65 days; LEE, n = 6 or late (65-128 days; LEL, n = 7 gestation (term approximately 147 days. Subsequent offspring remained on pasture until 1.5 years when all received glucose and insulin tolerance tests (GTT & ITT and body composition determination by dual energy x-ray absorptiometry (DXA. All animals were then exposed to an obesogenic environment for 6-7 months and all protocols repeated. Prenatal dietary treatment had no effect on birth weight or on metabolic endpoints when animals were 'lean' (1.5 years. Obesity revealed generalised metabolic 'inflexibility' and insulin resistance; characterised by blunted excursions of plasma NEFA and increased insulin(AUC (from 133 to 341 [s.e.d. 26] ng.ml(-1.120 mins during a GTT, respectively. For LEL vs. CE, the peak in plasma insulin when obese was greater (7.8 vs. 4.7 [s.e.d. 1.1] ng.ml(-1 and was exacerbated by offspring sex (i.e. 9.8 vs. 4.4 [s.e.d. 1.16] ng.ml(-1; LEL male vs. CE male, respectively. Acquisition of obesity also significantly influenced the plasma lipid and protein profile to suggest, overall, greater net lipogenesis and reduced protein metabolism. CONCLUSIONS: This study indicates generalised metabolic dysfunction with adult-onset obesity which also exacerbates and 'reveals' programming of glucose-insulin sensitivity in male offspring prenatally exposed to maternal undernutrition during late gestation. Taken together, the data suggest that metabolic function appears little compromised in young

  7. Transgenic tobacco plants having a higher level of methionine are more sensitive to oxidative stress.

    Science.gov (United States)

    Hacham, Yael; Matityahu, Ifat; Amir, Rachel

    2017-07-01

    Methionine is an essential amino acid the low level of which limits the nutritional quality of plants. We formerly produced transgenic tobacco (Nicotiana tabacum) plants overexpressing CYSTATHIONE γ-SYNTHASE (CGS) (FA plants), methionine's main regulatory enzyme. These plants accumulate significantly higher levels of methionine compared with wild-type (WT) plants. The aim of this study was to gain more knowledge about the effect of higher methionine content on the metabolic profile of vegetative tissue and on the morphological and physiological phenotypes. FA plants exhibit slightly reduced growth, and metabolic profiling analysis shows that they have higher contents of stress-related metabolites. Despite this, FA plants were more sensitive to short- and long-term oxidative stresses. In addition, compared with WT plants and transgenic plants expressing an empty vector, the primary metabolic profile of FA was altered less during oxidative stress. Based on morphological and metabolic phenotypes, we strongly proposed that FA plants having higher levels of methionine suffer from stress under non-stress conditions. This might be one of the reasons for their lesser ability to cope with oxidative stress when it appeared. The observation that their metabolic profiling is much less responsive to stress compared with control plants indicates that the delta changes in metabolite contents between non-stress and stress conditions is important for enabling the plants to cope with stress conditions. © 2017 Scandinavian Plant Physiology Society.

  8. Glucose tolerance, insulin sensitivity and insulin release in European non-diabetic carriers of a polymorphism upstream of CDKN2A and CDKN2B

    DEFF Research Database (Denmark)

    Hribal, M L; Presta, I; Procopio, T

    2011-01-01

    The aim of this study was to investigate the association of the rs10811661 polymorphism near the CDKN2B/CDKN2A genes with glucose tolerance, insulin sensitivity and insulin release in three samples of white people with European ancestry.......The aim of this study was to investigate the association of the rs10811661 polymorphism near the CDKN2B/CDKN2A genes with glucose tolerance, insulin sensitivity and insulin release in three samples of white people with European ancestry....

  9. Early insulin sensitivity after restrictive bariatric surgery, inconsistency between HOMA-IR and steady-state plasma glucose levels.

    Science.gov (United States)

    van Dielen, Francois M H; Nijhuis, Jeroen; Rensen, Sander S M; Schaper, Nicolaas C; Wiebolt, Janneke; Koks, Afra; Prakken, Fred J; Buurman, Wim A; Greve, Jan Willem M

    2010-01-01

    The low-grade inflammatory condition present in morbid obesity is thought to play a causative role in the pathophysiology of insulin resistance (IR). Bariatric surgery fails to improve this inflammatory condition during the first months after surgery. Considering the close relation between inflammation and IR, we conducted a study in which insulin sensitivity was measured during the first months after bariatric surgery. Different methods to measure IR shortly after bariatric surgery have given inconsistent data. For example, the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) levels have been reported to decrease rapidly after bariatric surgery, although clamp techniques have shown sustained insulin resistance. In the present study, we evaluated the use of steady-state plasma glucose (SSPG) levels to assess insulin sensitivity 2 months after bariatric surgery. Insulin sensitivity was measured using HOMA-IR and SSPG levels in 11 subjects before surgery and at 26% excess weight loss (approximately 2 months after restrictive bariatric surgery). The SSPG levels after 26% excess weight loss did not differ from the SSPG levels before surgery (14.3 +/- 5.4 versus 14.4 +/- 2.7 mmol/L). In contrast, the HOMA-IR values had decreased significantly (3.59 +/- 1.99 versus 2.09 +/- 1.02). During the first months after restrictive bariatric surgery, we observed a discrepancy between the HOMA-IR and SSPG levels. In contrast to the HOMA-IR values, the SSPG levels had not improved, which could be explained by the ongoing inflammatory state after bariatric surgery. These results suggest that during the first months after restrictive bariatric surgery, HOMA-IR might not be an adequate marker of insulin sensitivity. Copyright 2010 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  10. Stimulatory effect of insulin on glucose uptake by muscle involves the central nervous system in insulin-sensitive mice

    NARCIS (Netherlands)

    Coomans, Claudia P.; Biermasz, Nienke R.; Geerling, Janine J.; Guigas, Bruno; Rensen, Patrick C. N.; Havekes, Louis M.; Romijn, Johannes A.

    2011-01-01

    Insulin inhibits endogenous glucose production (EGP) and stimulates glucose uptake in peripheral tissues. Hypothalamic insulin signaling is required for the inhibitory effects of insulin on EGP. We examined the contribution of central insulin signaling on circulating insulin-stimulated

  11. Stimulatory effect of insulin on glucose uptake by muscle involves the central nervous system in insulin-sensitive mice

    NARCIS (Netherlands)

    Coomans, C.P.; Biermasz, N.R.; Geerling, J.J.; Guigas, B.; Rensen, P.C.N.; Havekes, L.M.; Romijn, J.A.

    2011-01-01

    OBJECTIVE - Insulin inhibits endogenous glucose production (EGP) and stimulates glucose uptake in peripheral tissues. Hypothalamic insulin signaling is required for the inhibitory effects of insulin on EGP. We examined the contribution of central insulin signaling on circulating insulin-stimulated

  12. The progression from a lower to a higher invasive stage of bladder cancer is associated with severe alterations in glucose and pyruvate metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Conde, Vanessa R. [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Oliveira, Pedro F. [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Department of Microscopy, Laboratory of Cell Biology and Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto – UMIB/ICBAS/UP (Portugal); Nunes, Ana R.; Rocha, Cátia S. [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Ramalhosa, Elsa; Pereira, José A. [Mountain Research Centre (CIMO), School of Agriculture, Polytechnic Institute of Bragança (Portugal); Alves, Marco G., E-mail: alvesmarc@gmail.com [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Silva, Branca M., E-mail: bmcms@ubi.pt [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal)

    2015-07-01

    Cancer cells present a particular metabolic behavior. We hypothesized that the progression of bladder cancer could be accompanied by changes in cells glycolytic profile. We studied two human bladder cancer cells, RT4 and TCCSUP, in which the latter represents a more invasive stage. The levels of glucose, pyruvate, alanine and lactate in the extracellular media were measured by Proton Nuclear Magnetic Resonance. The protein expression levels of glucose transporters 1 (GLUT1) and 3 (GLUT3), monocarboxylate transporter 4 (MCT4), phosphofructokinase-1 (PFK1), glutamic-pyruvate transaminase (GPT) and lactate dehydrogenase (LDH) were determined. Our data showed that glucose consumption and GLUT3 levels were similar in both cell lines, but TCCSUP cells displayed lower levels of GLUT1 and PFK expression. An increase in pyruvate consumption, concordant with the higher levels of lactate and alanine production, was also detected in TCCSUP cells. Moreover, TCCSUP cells presented lower protein expression levels of GPT and LDH. These results illustrate that bladder cancer progression is associated with alterations in cells glycolytic profile, namely the switch from glucose to pyruvate consumption in the more aggressive stage. This may be useful to develop new therapies and to identify biomarkers for cancer progression. - Highlights: • Metabolic phenotype of less and high invasive bladder cancer cells was studied. • Bladder cancer progression involves alterations in cells glycolytic profile. • More invasive bladder cancer cells switch from glucose to pyruvate consumption. • Our results may help to identify metabolic biomarkers of bladder cancer progression.

  13. Association between fasting plasma glucose and high-sensitivity C-reactive protein: gender differences in a Japanese community-dwelling population

    Directory of Open Access Journals (Sweden)

    Takayama Shuzo

    2011-06-01

    Full Text Available Abstract Background High sensitivity C-reactive protein (hsCRP is an acute phase reactant and a sensitive marker of inflammation. Hyperglycemia can potentially promote the production of CRP. The aim of this study was to determine whether increased fasting plasma glucose (FPG levels are associated with elevated hsCRP concentrations by gender. Methods We recruited 822 men (mean age, 61 ± 14 years and 1,097 women (63 ± 12 years during their annual health examination from a single community. We cross-sectionally examined whether FPG levels are associated with hsCRP concentrations, and whether this association is independent of gender, body mass index (BMI and other components of the metabolic syndrome. Results In women only, hsCRP increased significantly and progressively with increasing FPG (r = 0.169, P 2 and higher FPG than in men. Conclusions These results suggested that hsCRP levels increase continuously across the FPG spectrum starting from the lowest FPG in both men and women. However, increase in hsCRP levels was greater in women than men.

  14. Sustained high plasma mannose less sensitive to fluctuating blood glucose in glycogen storage disease type Ia children

    NARCIS (Netherlands)

    Nagasaka, Hironori; Yorifuji, Tohru; Bandsma, Robert H. J.; Takatani, Tomozumi; Asano, Hisaki; Mochizuki, Hiroshi; Takuwa, Mayuko; Tsukahara, Hirokazu; Inui, Ayano; Tsunoda, Tomoyuki; Komatsu, Haruki; Hiejima, Eitaro; Fujisawa, Tomoo; Hirano, Ken-ichi; Miida, Takashi; Ohtake, Akira; Taguchi, Tadao; Miwa, Ichitomo

    Plasma mannose is suggested to be largely generated from liver glycogen-oriented glucose-6-phosphate. This study examined plasma mannose in glycogen storage disease type Ia (GSD Ia) lacking conversion of glucose-6-phosphate to glucose in the liver. We initially examined fasting-and postprandial 2

  15. A high-throughput colorimetric assay for glucose detection based on glucose oxidase-catalyzed enlargement of gold nanoparticles

    Science.gov (United States)

    Xiong, Yanmei; Zhang, Yuyan; Rong, Pengfei; Yang, Jie; Wang, Wei; Liu, Dingbin

    2015-09-01

    We developed a simple high-throughput colorimetric assay to detect glucose based on the glucose oxidase (GOx)-catalysed enlargement of gold nanoparticles (AuNPs). Compared with the currently available glucose kit method, the AuNP-based assay provides higher clinical sensitivity at lower cost, indicating its great potential to be a powerful tool for clinical screening of glucose.We developed a simple high-throughput colorimetric assay to detect glucose based on the glucose oxidase (GOx)-catalysed enlargement of gold nanoparticles (AuNPs). Compared with the currently available glucose kit method, the AuNP-based assay provides higher clinical sensitivity at lower cost, indicating its great potential to be a powerful tool for clinical screening of glucose. Electronic supplementary information (ESI) available: Experimental section and additional figures. See DOI: 10.1039/c5nr03758a

  16. Driving higher magnetic field sensitivity of the martensitic transformation in MnCoGe ferromagnet

    Science.gov (United States)

    Ma, S. C.; Ge, Q.; Hu, Y. F.; Wang, L.; Liu, K.; Jiang, Q. Z.; Wang, D. H.; Hu, C. C.; Huang, H. B.; Cao, G. P.; Zhong, Z. C.; Du, Y. W.

    2017-11-01

    The sharp metamagnetic martensitic transformation (MMT) triggered by a low critical field plays a pivotal role in magnetoresponsive effects for ferromagnetic shape memory alloys (FSMAs). Here, a sharper magnetic-field-induced metamagnetic martensitic transformation (MFIMMT) is realized in Mn1-xCo1+xGe systems with a giant magnetocaloric effect around room temperature, which represents the lowest magnetic driving and completion fields as well as the largest magnetization difference around MFIMMT reported heretofore in MnCoGe-based FSMAs. More interestingly, a reversible MFIMMT with field cycling is observed in the Mn0.965Co0.035Ge compound. These results indicate that the consensus would be broken that the magnetic field is difficult to trigger the MMT for MnCoGe-based systems. The origin of a higher degree of sensitivity of martensitic transformation to the magnetic field is discussed based on the X-ray absorption spectroscopic results.

  17. Triglyceride glucose index as a surrogate measure of insulin sensitivity in obese adolescents with normoglycemia, prediabetes, and type 2 diabetes mellitus: Comparison with the hyperinsulinemic–euglycemic clamp

    Science.gov (United States)

    There is a need for simple surrogate estimates of insulin sensitivity in epidemiological studies of obese youth because the hyperinsulinemic-euglycemic clamp is not feasible on a large scale. Objectives: (i) To examine the triglyceride glucose (TyG) index (Ln[fasting triglycerides (mg/dL)'×'fasting ...

  18. Beneficial role of vitamin K supplementation on insulin sensitivity, glucose metabolism, and the reduced risk of type 2 diabetes: A review.

    Science.gov (United States)

    Manna, Prasenjit; Kalita, Jatin

    2016-01-01

    Micronutrients are gaining acceptance as an important nutritional therapy for the prevention and/or management of diabetes and its associated health risks. Although a very small quantity of micronutrients are required for specific functions in our bodies, moderate deficiencies can lead to serious health issues. Impaired insulin sensitivity and glucose intolerance play a major role in the development of diabetic pathophysiology. Vitamin K is well known for its function in blood coagulation. Moreover, several human studies reported the beneficial role of vitamin K supplementation in improving insulin sensitivity and glucose tolerance, preventing insulin resistance, and reducing the risk of type 2 diabetes (T2 D). Both animal and human studies have suggested that vitamin K-dependent protein (osteocalcin [OC]), regulation of adipokine levels, antiinflammatory properties, and lipid-lowering effects may mediate the beneficial function of vitamin K in insulin sensitivity and glucose tolerance. This review for the first time provides an overview of the currently available preclinical and clinical evidences on the effect of vitamin K supplementation in the management of insulin sensitivity and glucose tolerance. The outcome of this review will increase understanding for the development of a novel adjuvant therapy to achieve better control of glycemia and improve the lives of diabetic patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Evidence for a relationship between VEGF and BMI independent of insulin sensitivity by glucose clamp procedure in a homogenous group healthy young men.

    Directory of Open Access Journals (Sweden)

    Michaela Loebig

    Full Text Available BACKGROUND: This is the first study to experimentally explore the direct relationship between circulating VEGF levels and body mass index (BMI as well as to unravel the role of insulin sensitivity in this context under standardized glucose clamp conditions as the methodical gold-standard. In order to control for known influencing factors such as gender, medication, and arterial hypertension, we examined a highly homogeneous group of young male subjects. Moreover, to encompass also subjects beyond the normal BMI range, low weight and obese participants were additionally included and stress hormones as a main regulator of VEGF were assessed. METHODOLOGY/PRINCIPAL FINDINGS: Under euglycemic clamp conditions, VEGF was measured in 15 normal weight (BMI 20-25 kg/m(2, 15 low weight (BMI30 kg/m(2 male subjects aged 18-30 years and the insulin sensitivity index (ISI was calculated. Since stress axis activation promotes VEGF secretion, concentrations of ACTH, cortisol, and catecholamines were monitored. Despite of comparable ACTH (P = 0.145, cortisol (P = 0.840, and norepinephrine (P = 0.065 levels, VEGF concentrations differed significantly between BMI-groups (P = 0.008 with higher concentrations in obese subjects as compared to normal weight (P = 0.061 and low weight subjects (P = 0.002. Pearson's correlation analysis revealed a positive relationship between BMI and VEGF levels (r = 0.407; P = 0.010 but no correlation of VEGF with ISI (r = 0.224; P = 0.175. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a positive correlation between concentrations of circulating VEGF levels and BMI in healthy male subjects under highly controlled conditions. This relationship which is apparently disconnected from insulin sensitivity may be part of some pathogenetic mechanisms underlying obesity and type 2 diabetes.

  20. Sensitive determination of glucose in Dulbecco's modified Eagle medium by high-performance liquid chromatography with 1-phenyl-3-methyl-5-pyrazolone derivatization: application to gluconeogenesis studies.

    Science.gov (United States)

    Ling, Zhaoli; Xu, Ping; Zhong, Zeyu; Wang, Fan; Shu, Nan; Zhang, Ji; Tang, Xiange; Liu, Li; Liu, Xiaodong

    2016-04-01

    A new pre-column derivative high-performance liquid chromatography (HPLC) method for determination of d-glucose with 3-O-methyl-d-glucose (3-OMG) as the internal standard was developed and validated in order to study the gluconeogenesis in HepG2 cells. Samples were derivatized with 1-phenyl-3-methy-5-pyrazolone at 70°C for 50 min. Glucose and 3-OMG were extracted by liquid-liquid extraction and separated on a YMC-Triart C18 column, with a gradient mobile phase composed of acetonitrile and 20 mm ammonium acetate solution containing 0.09% tri-ethylamine at a flow rate of 1.0 mL/min. The eluate were detected using a UV detector at 250 nm. The assay was linear over the range 0.39-25 μm (R(2) = 0.9997, n = 5) and the lower limit of quantitation was 0.39 μm (0.070 mg/mL). Intra- and inter-day precision and accuracy were gluconeogenesis in Dulbecco's modified Eagle medium (DMEM) cultured HepG2 cells. Glucose concentration was determined to be about 1-2.5 μm in this gluconeogenesis assay. In conclusion, this method has been shown to determine small amounts of glucose in DMEM successfully, with lower limit of quantitation and better sensitivity when compared with common commercial glucose assay kits. Copyright © 2015 John Wiley & Sons, Ltd.

  1. Higher assimilation than respiration sensitivity to drought for a desert ecosystem in Central Asia.

    Science.gov (United States)

    Gu, Daxing; Otieno, Dennis; Huang, Yuqing; Wang, Quan

    2017-12-31

    Responses of ecosystem assimilation and respiration to global climate change vary considerably among terrestrial ecosystems constrained by both biotic and abiotic factors. In this study, net CO 2 exchange between ecosystem and atmosphere (NEE) was measured over a 4-year period (2013-2016) using eddy covariance technology in a desert ecosystem in Central Asia. Ecosystem assimilation (gross primary production, GPP) and respiration (R eco ) were derived from NEE by fitting light response curves to NEE data based on day- and nighttime data, and their responses to soil water content (SWC) and evaporative fraction (EF) were assessed during the growing season. Results indicated that both GPP and R eco linearly decreased with declining SWC, with the sensitivity of GPP to SWC being 3.8 times higher than that of R eco during the entire growing season. As a result, ecosystem CO 2 sequestration capacity decreased from 4.00μmolm -2 s -1 to 1.00μmolm -2 s -1 , with increasing soil drought . On a seasonal scale, significant correlation between GPP and SWC was only found in spring while that between R eco and SWC was found in all growing seasons with the sensitivity increasing steadily from spring to autumn. EF had a low correlation with SWC, GPP and R eco (R 2 =0.03, 0.02, 0.05, respectively), indicating that EF was not a good proxy for soil drought and energy partitioning was not tightly coupled to ecosystem carbon exchanges in this desert ecosystem. The study deepens our knowledge of ecosystem carbon exchange and its response to drought as well as its coupling with ecosystem energy partitioning in an extreme dry desert. The information is critical for better assessing carbon sequestration capacity in dryland, and for understanding its feedback to climate change. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Enhanced sensitivity in non-enzymatic glucose detection by improved growth kinetics of Ni-based nanostructures

    Science.gov (United States)

    Urso, M.; Pellegrino, G.; Strano, V.; Bruno, E.; Priolo, F.; Mirabella, S.

    2018-04-01

    Ni-based nanostructures are attractive catalytic materials for many electrochemical applications, among which are non-enzymatic sensing, charge storage, and water splitting. In this work, we clarify the synthesis kinetics of Ni(OH)2/NiOOH nanowalls grown by chemical bath deposition at room temperature and at 50 °C. We applied the results to non-enzymatic glucose sensing, reaching a highest sensitivity of 31 mA cm-2mM-1. Using scanning electron microscopy, x-ray diffraction analysis and Rutherford backscattering spectrometry we found that the growth occurs through two regimes: first, a quick random growth leading to disordered sheets of Ni oxy-hydroxide, followed by a slower growth of well-aligned sheets of Ni hydroxide. A high growth temperature (50 °C), leading mainly to well-aligned sheets, offers superior electrochemical properties in terms of charge storage, charge carrier transport and catalytic action, as confirmed by cyclic voltammetry and electrochemical impedance spectroscopy analyses. The reported results on the optimization and application of low-cost synthesis of these Ni-based nanostructures have a large potential for application in catalysis, (bio)sensing, and supercapacitors areas.

  3. Identification of four amino acid substitutions in hexokinase II and studies of relationships to NIDDM, glucose effectiveness, and insulin sensitivity

    DEFF Research Database (Denmark)

    Echwald, Søren Morgenthaler; Bjørbaek, C; Hansen, Torben

    1995-01-01

    not predict any change in amino acid composition of the protein. One homozygous and nine heterozygous carriers of the codon 142 mutation were found among the NIDDM patients. The mutations at codons 148, 497, and 844 were each found in one diabetic subject and only on one allele. There were no carriers......Human hexokinase (HK) II, a glucose phosphorylating enzyme in muscle tissue, plays a central role in glucose metabolism. Since reduced insulin-stimulated glucose uptake and reduced glucose-6-phosphate content in muscle have been demonstrated in pre-non-insulin-dependent diabetes mellitus (pre...

  4. The Relationship between Ethical Sensitivity, High Ability and Gender in Higher Education Students

    Science.gov (United States)

    Schutte, Ingrid; Wolfensberger, Marca; Tirri, Kirsi

    2014-01-01

    This study examined the ethical sensitivity of high-ability undergraduate students (n=731) in the Netherlands who completed the 28-item Ethical Sensitivity Scale Questionnaire (ESSQ) developed by Tirri & Nokelainen (2007; 2011). The ESSQ is based on Narvaez' (2001) operationalization of ethical sensitivity in seven dimensions. The following…

  5. A Paleolithic diet confers higher insulin sensitivity, lower C-reactive protein and lower blood pressure than a cereal-based diet in domestic pigs

    Directory of Open Access Journals (Sweden)

    Ugander Martin

    2006-11-01

    Full Text Available Abstract Background A Paleolithic diet has been suggested to be more in concordance with human evolutionary legacy than a cereal based diet. This might explain the lower incidence among hunter-gatherers of diseases of affluence such as type 2 diabetes, obesity and cardiovascular disease. The aim of this study was to experimentally study the long-term effect of a Paleolithic diet on risk factors for these diseases in domestic pigs. We examined glucose tolerance, post-challenge insulin response, plasma C-reactive protein and blood pressure after 15 months on Paleolithic diet in comparison with a cereal based swine feed. Methods Upon weaning twenty-four piglets were randomly allocated either to cereal based swine feed (Cereal group or cereal free Paleolithic diet consisting of vegetables, fruit, meat and a small amount of tubers (Paleolithic group. At 17 months of age an intravenous glucose tolerance test was performed and pancreas specimens were collected for immunohistochemistry. Group comparisons of continuous variables were made by use of the t-test. P Results At the end of the study the Paleolithic group weighed 22% less and had 43% lower subcutaneous fat thickness at mid sternum. No significant difference was seen in fasting glucose between groups. Dynamic insulin sensitivity was significantly higher (p = 0.004 and the insulin response was significantly lower in the Paleolithic group (p = 0.001. The geometric mean of C-reactive protein was 82% lower (p = 0.0007 and intra-arterial diastolic blood pressure was 13% lower in the Paleolithic group (p = 0.007. In evaluations of multivariate correlations, diet emerged as the strongest explanatory variable for the variations in dynamic insulin sensitivity, insulin response, C-reactive protein and diastolic blood pressure when compared to other relevant variables such as weight and subcutaneous fat thickness at mid sternum. There was no obvious immunohistochemical difference in pancreatic islets

  6. Enhancement in the antitumor immunity contributes to the radio-sensitization of tumors by 2-deoxy-D-glucose

    International Nuclear Information System (INIS)

    Farooque, Abdullah; Dwarakanath, B.S.

    2014-01-01

    The glycolytic inhibitor, 2-deoxy-D-glucose sensitizes tumor cells while protects normal cells to radiation and chemotherapeutics in vitro and in vivo. Further, 2-DG has also been suggested as an adjuvant for low dose radiation therapy. Since immunomodulation plays an important role in tumor responses to anticancer therapies and glycolysis influences the activation of lymphocytes, we investigated the effects of 2-DG on immuno-regulatory networks during radiosensitization of Ehrlich ascites tumor (EAT) in mice. Mice were treated with 10 Gy of focal irradiation to tumor and single dose of 2-DG (2 gm/Kg/b.wt) intravenously. Immuno-phenotyping was done using flow cytometry, while cytokines and antibody classes were analyzed using bead array and ELISA. Further, mRNA and protein levels of transcription factors were assessed in sorted splenic CD4 + cells using real time PCR and Western blot techniques. Immune activation in the form of increase in the expression of NK cells, dendritic cells, macrophages and CD4 + cells, while a decrease was noted in myeloid derived suppressor cells (MDSCs), B cells, tumor tolerant CD4 + PD1 + and CD8 + PD1 + after the combined treatment (2-DG+ Radiation). Interestingly, decrease in the (CD4 + CD62L + ) naive cells with concomitant increase in effector memory cells (CD4 + CD44 + ) indicated the immune activation and memory response. This activation was found to be dependent on the restoration of TCR and CD28 mediated signaling leading to the shift from Th2 and Th17 to Th1 in the form of cytokine and antibody class switching and decrease in inflammation, which was correlated with the modulation of transcriptional factors in splenic CD4 + cells. Interestingly, depletion of T-regulatory cells appears to be partly responsible for the immune activation observed. These studies for the first time revealed the immuno-modulatory potential of 2-DG that should facilitate the optimization of protocols for enhancing the efficacy of radiotherapy, besides

  7. Fibroid explants reveal a higher sensitivity against MDM2-inhibitor nutlin-3 than matching myometrium

    Directory of Open Access Journals (Sweden)

    Markowski Dominique N

    2012-01-01

    Full Text Available Abstract Background Spontaneous cessation of growth is a frequent finding in uterine fibroids. Increasing evidence suggests an important role of cellular senescence in this growth control. Deciphering the underlying mechanisms of growth control that can be expected not only to shed light on the biology of the tumors but also to identify novel therapeutic targets. Methods We have analyzed uterine leiomyomas and matching normal tissue for the expression of p14Arf and used explants to see if reducing the MDM2 activity using the small-molecule inhibitor nutlin-3 can induce p53 and activate genes involved in senescence and/or apoptosis. For these studies quantitative real-time RT-PCR, Western blots, and immunohistochemistry were used. Statistical analyses were performed using the student's t test. Results An in depth analysis of 52 fibroids along with matching myometrium from 31 patients revealed in almost all cases a higher expression of p14Arf in the tumors than in the matching normal tissue. In tissue explants, treatment with the MDM2 inhibitor nutlin-3 induced apoptosis as well as senescence as revealed by a dose-dependent increase of the expression of BAX as well as of p21, respectively. Simultaneously, the expression of the proliferation marker Ki-67 drastically decreased. Western-blot analysis identified an increase of the p53 level as the most likely reason for the increased activity of its downstream markers BAX and p21. Because as a rule fibroids express much higher levels of p14Arf, a major negative regulator of MDM2, than matching myometrium it was then analyzed if fibroids are more sensitive against nutlin-3 treatment than matching myometrium. We were able to show that in most fibroids analyzed a higher sensibility than that of matching myometrium was noted with a corresponding increase of the p53 immunopositivity of the fibroid samples compared to those from myometrium. Conclusions The results show that uterine fibroids represent a cell

  8. Glucose aided preparation of tungsten sulfide/multi-wall carbon nanotube hybrid and use as counter electrode in dye-sensitized solar cells.

    Science.gov (United States)

    Wu, Jihuai; Yue, Gentian; Xiao, Yaoming; Huang, Miaoliang; Lin, Jianming; Fan, Leqing; Lan, Zhang; Lin, Jeng-Yu

    2012-12-01

    The tungsten sulfide/multi-wall carbon nanotube (WS(2)/MWCNT) hybrid was prepared in the presence of glucose by the hydrothermal route. The hybrid materials were used as counter electrode in the dye-sensitized solar cell (DSSC). The results of cyclic voltammetry measurement and electrochemical impedance spectroscopy indicated that the glucose aided prepared (G-A) WS(2)/MWCNT electrode had low charge-transfer resistance (R(ct)) and high electrocatalytic activity for triiodide reduction. The excellent electrochemical properties for (G-A) WS(2)/MWCNT electrode is due to the synergistic effects of WS(2) and MWCNTs, as well as amorphous carbon introduced by glucose. The DSSC based on the G-A WS(2)/MWCNT counter electrode achieved a high power conversion efficiency of 7.36%, which is comparable with the performance of the DSSC using Pt counter electrode (7.54%).

  9. Oral treatment with γ-aminobutyric acid improves glucose tolerance and insulin sensitivity by inhibiting inflammation in high fat diet-fed mice.

    Directory of Open Access Journals (Sweden)

    Jide Tian

    Full Text Available Adipocyte and β-cell dysfunction and macrophage-related chronic inflammation are critical for the development of obesity-related insulin resistance and type 2 diabetes mellitus (T2DM, which can be negatively regulated by Tregs. Our previous studies and those of others have shown that activation of γ-aminobutyric acid (GABA receptors inhibits inflammation in mice. However, whether GABA could modulate high fat diet (HFD-induced obesity, glucose intolerance and insulin resistance has not been explored. Here, we show that although oral treatment with GABA does not affect water and food consumption it inhibits the HFD-induced gain in body weights in C57BL/6 mice. Furthermore, oral treatment with GABA significantly reduced the concentrations of fasting blood glucose, and improved glucose tolerance and insulin sensitivity in the HFD-fed mice. More importantly, after the onset of obesity and T2DM, oral treatment with GABA inhibited the continual HFD-induced gain in body weights, reduced the concentrations of fasting blood glucose and improved glucose tolerance and insulin sensitivity in mice. In addition, oral treatment with GABA reduced the epididymal fat mass, adipocyte size, and the frequency of macrophage infiltrates in the adipose tissues of HFD-fed mice. Notably, oral treatment with GABA significantly increased the frequency of CD4(+Foxp3(+ Tregs in mice. Collectively, our data indicated that activation of peripheral GABA receptors inhibited the HFD-induced glucose intolerance, insulin resistance, and obesity by inhibiting obesity-related inflammation and up-regulating Treg responses in vivo. Given that GABA is safe for human consumption, activators of GABA receptors may be valuable for the prevention of obesity and intervention of T2DM in the clinic.

  10. Fibroblasts maintained in 3 dimensions show a better differentiation state and higher sensitivity to estrogens

    Energy Technology Data Exchange (ETDEWEB)

    Montani, Claudia [Laboratory of Biotechnology, Department of Laboratory Medicine, Civic Hospital of Brescia (Italy); Steimberg, Nathalie; Boniotti, Jennifer [Laboratory of Tissue Engineering, Anatomy and Physiopathology Unit, Department of Clinical and Experimental Sciences, School of Medicine, University of Brescia (Italy); Biasiotto, Giorgio; Zanella, Isabella [Laboratory of Biotechnology, Department of Laboratory Medicine, Civic Hospital of Brescia (Italy); Department of Molecular and Translational Medicine, University of Brescia, Brescia (Italy); Diafera, Giuseppe [Integrated Systems Engineering (ISE), Milan (Italy); Biunno, Ida [IRGB-CNR, Milan (Italy); IRCCS-Multimedica, Milan (Italy); Caimi, Luigi [Laboratory of Biotechnology, Department of Laboratory Medicine, Civic Hospital of Brescia (Italy); Department of Molecular and Translational Medicine, University of Brescia, Brescia (Italy); Mazzoleni, Giovanna [Laboratory of Tissue Engineering, Anatomy and Physiopathology Unit, Department of Clinical and Experimental Sciences, School of Medicine, University of Brescia (Italy); Di Lorenzo, Diego, E-mail: diego.dilorenzo@yahoo.it [Laboratory of Biotechnology, Department of Laboratory Medicine, Civic Hospital of Brescia (Italy)

    2014-11-01

    maintaining cells in more physiological conditions. • RCCS-cultured fibroblasts showed higher hormonal sensitivity to estradiol. • This bioreactor is a novel 3D model to be applied to pharmacotoxicological studies.

  11. The glucose oxidase-peroxidase assay for glucose

    Science.gov (United States)

    The glucose oxidase-peroxidase assay for glucose has served as a very specific, sensitive, and repeatable assay for detection of glucose in biological samples. It has been used successfully for analysis of glucose in samples from blood and urine, to analysis of glucose released from starch or glycog...

  12. Natto and viscous vegetables in a Japanese-style breakfast improved insulin sensitivity, lipid metabolism and oxidative stress in overweight subjects with impaired glucose tolerance.

    Science.gov (United States)

    Taniguchi-Fukatsu, Akiko; Yamanaka-Okumura, Hisami; Naniwa-Kuroki, Yuko; Nishida, Yuka; Yamamoto, Hironori; Taketani, Yutaka; Takeda, Eiji

    2012-04-01

    We previously suggested that the consumption of natto and viscous vegetables as part of a Japanese-style meal based on white rice (WR) reduced postprandial glucose and insulin levels in healthy subjects. The aim of the present study was to assess whether a single breakfast of natto and viscous vegetables or the same breakfast consumed for 2 weeks could improve glucose control, insulin sensitivity, lipid metabolism and oxidative stress in overweight subjects with impaired glucose tolerance (IGT). A total of eleven free-living subjects with IGT followed a randomised, crossover breakfast intervention for 2 weeks. The test meal included boiled WR with natto (viscous fermented soyabeans), Japanese yam and okra. The control meal included WR with non-viscous boiled soyabeans, potatoes and broccoli. Both meals contained comparable amounts of carbohydrate, fat, protein and fibre. The test meal reduced acute glucose and insulin responses compared to the control meal in the study participants. Insulin sensitivity was assessed using the composite insulin sensitivity index (CISI) after both the test and control meal periods. The test meal resulted in improvements in CISI compared to the baseline, whereas no significant changes were observed after the control meal period. Serum levels of both total and LDL-cholesterol were assessed before and after the test meal period and found to decrease significantly. There was also a tendency towards reduced serum malondialdehyde-modified LDL and N(ɛ)-carboxymethyllysine. No differences were observed in the measures of chronic glycaemic control. Thus, we conclude that a breakfast of natto and viscous vegetables consumed for 2 weeks improves insulin sensitivity, serum lipid and oxidative stress.

  13. Triglyceride glucose index as a surrogate measure of insulin sensitivity in obese adolescents with normoglycemia, prediabetes, and type 2 diabetes mellitus: comparison with the hyperinsulinemic-euglycemic clamp.

    Science.gov (United States)

    Mohd Nor, Noor Shafina; Lee, SoJung; Bacha, Fida; Tfayli, Hala; Arslanian, Silva

    2016-09-01

    There is a need for simple surrogate estimates of insulin sensitivity in epidemiological studies of obese youth because the hyperinsulinemic-euglycemic clamp is not feasible on a large scale. (i) To examine the triglyceride glucose (TyG) index (Ln[fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]) and its relationship to in vivo insulin sensitivity in obese adolescents (OB) along the spectrum of glucose tolerance and (ii) to compare TyG index with triglyceride/high-density lipoprotein TG/HDL and 1/fasting insulin (1/IF ), other surrogates of insulin sensitivity. Cross-sectional data in 225 OB with normal glucose tolerance (NGT), prediabetes (preDM), and type 2 diabetes (T2DM) who had a 3-h hyperinsulinemic-euglycemic clamp and fasting lipid measurement. Insulin-stimulated glucose disposal (Rd) declined significantly across the glycemic groups from OB-NGT to OB-preDM to OB-T2DM with a corresponding increase in TyG index (8.3 ± 0.5, 8.6 ± 0.5, 8.9 ± 0.6, p index to Rd was -0.419 (p index for diagnosis of insulin resistance was 8.52 [receiver operating characteristic-area under the ROC curves (ROC-AUC) 0.750, p index, 1/IF , body mass index (BMI) z-score, glycemic group, and sex. The TyG index affords an easily and widely available simple laboratory method as a surrogate estimate of insulin sensitivity that could be used repeatedly in large-scale observational and/or interventional cohorts of OB. Although not superior to 1/IF , TyG index offers the advantage of having a standardized method of measuring triglyceride and glucose, which is not the case for insulin assays. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. A novel method for sensitive, low-cost and portable detection of hepatitis B surface antigen using a personal glucose meter.

    Science.gov (United States)

    Taebi, Saeed; Keyhanfar, Mehrnaz; Noorbakhsh, Abdollah

    2018-04-12

    Hepatitis B virus (HBV) infection is the major public health problem leading cause of death worldwide. The most important diagnostic marker for this infection is hepatitis B surface antigen (HBsAg). In this study, a novel, inexpensive, portable and sensitive ELISA method was designed and investigated for diagnosis of HBsAg based on the functionalized Fe 3 O 4 and Al 2 O 3 nanoparticles, with the strategy for detecting the concentration of glucose using a cheap and accessible personal glucose meter (PGM). The ELISA system was constructed using hepatitis B antibody against HBsAg immobilized on streptavidin coated magnetic iron oxide particles (S-Fe 3 O 4 ) as the capture antibody (Ab 1 ). In addition, another hepatitis B antibody against different epitope of HBsAg (Ab 2 ) and glucoamylase both were immobilized on Al 2 O 3 nanoparticles. After formation of the sandwich immune complex between Ab 1 and Ab 2 immobilized on S-Fe 3 O 4 and Al 2 O 3 NPs, respectively, through HBsAg, starch was converted into glucose using glucoamylase. Then, the glucose concentration was measured using PGM. The concentration of HBsAg was calculated based on the linear relation between the concentrations of HBsAg and glucose. Under optimal conditions, this assay showed detection limit values of 0.3 to 0.4 ng ml -1 for "ay" and "ad" subtypes of HBsAg, respectively. The results indicate that the designed assay is comparable to the commercial kits in terms of sensitivity, on-site, specificity, cost, simplicity, portability and reproducibility. The presented method can be used in disadvantaged areas of the world and blood transfusion centers. To the best of our knowledge, this is the first report of using PGMs for HBSAg detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Lower neighborhood quality in adolescence predicts higher mesolimbic sensitivity to reward anticipation in adulthood

    Science.gov (United States)

    Gonzalez, Marlen Z.; Allen, Joseph P.; Coan, James A.

    2016-01-01

    Life history theory suggests that adult reward sensitivity should be best explained by childhood, but not current, socioeconomic conditions. In this functional magnetic resonance imaging (fMRI) study, 83 participants from a larger longitudinal sample completed the monetary incentive delay (MID) task in adulthood (~25 years old). Parent-reports of neighborhood quality and parental SES were collected when participants were 13 years of age. Current income level was collected concurrently with scanning. Lower adolescent neighborhood quality, but neither lower current income nor parental SES, was associated with heightened sensitivity to the anticipation of monetary gain in putative mesolimbic reward areas. Lower adolescent neighborhood quality was also associated with heightened sensitivity to the anticipation of monetary loss activation in visuo-motor areas. Lower current income was associated with heightened sensitivity to anticipated loss in occipital areas and the operculum. We tested whether externalizing behaviors in childhood or adulthood could better account for neighborhood quality findings, but they did not. Findings suggest that neighborhood ecology in adolescence is associated with greater neural reward sensitivity in adulthood above the influence of parental SES or current income and not mediated through impulsivity and externalizing behaviors. PMID:27838595

  16. Lower neighborhood quality in adolescence predicts higher mesolimbic sensitivity to reward anticipation in adulthood

    Directory of Open Access Journals (Sweden)

    Marlen Z. Gonzalez

    2016-12-01

    Full Text Available Life history theory suggests that adult reward sensitivity should be best explained by childhood, but not current, socioeconomic conditions. In this functional magnetic resonance imaging (fMRI study, 83 participants from a larger longitudinal sample completed the monetary incentive delay (MID task in adulthood (∼25 years old. Parent-reports of neighborhood quality and parental SES were collected when participants were 13 years of age. Current income level was collected concurrently with scanning. Lower adolescent neighborhood quality, but neither lower current income nor parental SES, was associated with heightened sensitivity to the anticipation of monetary gain in putative mesolimbic reward areas. Lower adolescent neighborhood quality was also associated with heightened sensitivity to the anticipation of monetary loss activation in visuo-motor areas. Lower current income was associated with heightened sensitivity to anticipated loss in occipital areas and the operculum. We tested whether externalizing behaviors in childhood or adulthood could better account for neighborhood quality findings, but they did not. Findings suggest that neighborhood ecology in adolescence is associated with greater neural reward sensitivity in adulthood above the influence of parental SES or current income and not mediated through impulsivity and externalizing behaviors.

  17. Natural history of insulin sensitivity and insulin secretion in the progression from normal glucose tolerance to impaired fasting glycemia and impaired glucose tolerance: the Inter99 study

    DEFF Research Database (Denmark)

    Faerch, Kristine; Vaag, Allan; Holst, Jens J

    2008-01-01

    of insulin sensitivity (HOMA-IS), early-phase insulin release (EPIR), and insulin secretion relative to insulin action (disposition index) were estimated. RESULTS: Five years before the pre-diabetes diagnoses (i-IFG, i-IGT, and IFG/IGT), ISI, HOMA-IS, EPIR, and disposition index were lower than...

  18. The Compton Camera - medical imaging with higher sensitivity Exhibition LEPFest 2000

    CERN Multimedia

    2000-01-01

    The Compton Camera reconstructs the origin of Compton-scattered X-rays using electronic collimation with Silicon pad detectors instead of the heavy conventional lead collimators in Anger cameras - reaching up to 200 times better sensitivity and a factor two improvement in resolution. Possible applications are in cancer diagnosis, neurology neurobiology, and cardiology.

  19. Lower omental t-regulatory cell count is associated with higher fasting glucose and lower β-cell function in adults with obesity.

    Science.gov (United States)

    Gyllenhammer, Lauren E; Lam, Jonathan; Alderete, Tanya L; Allayee, Hooman; Akbari, Omid; Katkhouda, Namir; Goran, Michael I

    2016-06-01

    T-lymphocytes are potential initiators and regulators of adipose tissue (AT) inflammation, but there is limited human data on omental AT. The aim of this study was to assess the relationship between T cells, particularly Foxp3+ regulatory T (Treg) cells, in human subcutaneous (subQ) and omental AT and type 2 diabetes risk. SubQ and deep subQ (DsubQ) abdominal and omental AT biopsies were collected from 44 patients (body mass index, BMI ≥25) undergoing elective abdominal surgery. Flow cytometry was used to quantify CD4+ T cell (T effector and Treg) and macrophages (M1 and M2), and systemic inflammation was measured in fasting blood. Tregs were significantly lower in omental versus subQ and DsubQ AT, and M1 cell counts were significantly higher in the omental and DsubQ depot relative to the subQ. Only omental AT Tregs were negatively associated with fasting glucose and MCP-1 and positively associated with homeostasis model assessment (HOMA)-β. M1 and M2 cell counts across multiple depots had significant relationships with HOMA-insulin resistance, tumor necrosis factor-α, insulin, and HOMA-β. All relationships were consistent across ethnicities. Tregs were significantly lower in omental versus both subQ adipose depots. Fewer omental Tregs may have metabolic implications based on depot-specific relationships with higher fasting glucose and lower β-cell function. © 2016 The Obesity Society.

  20. Glucose oxidase-initiated cascade catalysis for sensitive impedimetric aptasensor based on metal-organic frameworks functionalized with Pt nanoparticles and hemin/G-quadruplex as mimicking peroxidases.

    Science.gov (United States)

    Zhou, Xingxing; Guo, Shijing; Gao, Jiaxi; Zhao, Jianmin; Xue, Shuyan; Xu, Wenju

    2017-12-15

    Based on cascade catalysis amplification driven by glucose oxidase (GOx), a sensitive electrochemical impedimetric aptasensor for protein (carcinoembryonic antigen, CEA as tested model) was proposed by using Cu-based metal-organic frameworks functionalized with Pt nanoparticles, aptamer, hemin and GOx (Pt@CuMOFs-hGq-GOx). CEA aptamer loaded onto Pt@CuMOFs was bound with hemin to form hemin@G-quadruplex (hGq) with mimicking peroxidase activity. Through sandwich-type reaction of target CEA and CEA aptamers (Apt1 and Apt2), the obtained Pt@CuMOFs-hGq-GOx as signal transduction probes (STPs) was captured to the modified electrode interface. When 3,3-diaminobenzidine (DAB) and glucose were introduced, the cascade reaction was initiated by GOx to catalyze the oxidation of glucose, in situ generating H 2 O 2 . Simultaneously, the decomposition of the generated H 2 O 2 was greatly promoted by Pt@CuMOFs and hGq as synergistic peroxide catalysts, accompanying with the significant oxidation process of DAB and the formation of nonconductive insoluble precipitates (IPs). As a result, the electron transfer in the resultant sensing interface was effectively hindered and the electrochemical impedimetric signal (EIS) was efficiently amplified. Thus, the high sensitivity of the proposed CEA aptasensor was successfully improved with 0.023pgmL -1 , which may be promising and potential in assaying certain clinical disease related to CEA. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Review on the Gender Sensitive Women Education- Legal Revolution in Higher Education

    OpenAIRE

    Pradeep M. D

    2017-01-01

    Education spreads parallel with the life span of a person starting from his birth to death. Education is known to be the instrument which fills human actions with the essence of values, dignity, ethics and human virtues. Life progress along with the process of civilization equipped with social, moral, cultural attributes in the path of education. The Educational system should be gender sensitive to impart knowledge and disseminate skills to the marginalized sections of the society. The countr...

  2. Dysregulation of glucose metabolism even in Chinese PCOS women with normal glucose tolerance.

    Science.gov (United States)

    Li, Weiping; Li, Qifu

    2012-01-01

    To clarify the necessity of improving glucose metabolism in polycystic ovary syndrome (PCOS) women as early as possible, 111 PCOS women with normal glucose tolerance and 92 healthy age-matched controls were recruited to investigate glucose levels distribution, insulin sensitivity and β cell function. 91 PCOS women and 33 controls underwent hyperinsulinemic-euglycemic clamp to assess their insulin sensitivity, which was expressed as M value. β cell function was estimated by homeostatic model assessment (HOMA)-β index after adjusting insulin sensitivity (HOMA-βad index). Compared with lean controls, lean PCOS women had similar fasting plasma glucose (FPG), higher postprandial plasma glucose (PPG) (6.03±1.05 vs. 5.44±0.97 mmol/L, PPCOS women had higher levels of both FPG (5.24±0.58 vs. 4.90±0.39, PPCOS women separately, and the cutoff of BMI indicating impaired β cell function of PCOS women was 25.545kg/m². In conclusion, insulin resistance and dysregulation of glucose metabolism were common in Chinese PCOS women with normal glucose tolerance. BMI ≥ 25.545kg/m² indicated impaired β cell function in PCOS women with normal glucose tolerance.

  3. A randomized trial comparing the effect of weight loss and exercise training on insulin sensitivity and glucose metabolism in coronary artery disease

    DEFF Research Database (Denmark)

    Pedersen, Lene Rørholm; Olsen, Rasmus Huan; Jürs, Anders

    2015-01-01

    followed by 2-4 weeks' weight maintenance diet. Glucose tolerance, insulin action, β-cell function and suppression of lipolysis were assessed using a 3-h oral glucose tolerance test. ISI-composite and ISI-HOMA (=1/HOMA-IR) were calculated as surrogate measures of whole-body and hepatic insulin sensitivity......, respectively. Magnetic resonance imaging estimated abdominal adipose tissue. Twenty-six (74%) AIT and 29 (83%) LED participants completed intervention per protocol. LED increased ISI-composite by 55% and ISI-HOMA by 70% (p0.7) revealing a significant...... difference between the groups (pHOMA and ISI-composite were associated with reduced visceral abdominal fat, waist circumference and body weight. Intention-to-treat analyses (n=64...

  4. Attenuated Effects of Bile Acids on Glucose Metabolism and Insulin Sensitivity in a Male Mouse Model of Prenatal Undernutrition

    NARCIS (Netherlands)

    Ma, Huijuan; Sales, Vicencia M.; Wolf, Ashley R.; Subramanian, Sathish; Matthews, Tucker J.; Chen, Michael; Sharma, Aparna; Gall, Walt; Kulik, Wim; Cohen, David E.; Adachi, Yusuke; Griffin, Nicholas W.; Gordon, Jeffrey I.; Patti, Mary-Elizabeth; Isganaitis, Elvira

    2017-01-01

    Prenatal undernutrition and low birth weight are associated with risk of type 2 diabetes and obesity. Prenatal caloric restriction results in low birth weight, glucose intolerance, obesity, and reduced plasma bile acids (BAs) in offspring mice. Because BAs can regulate systemic metabolism and

  5. Subthalamic nucleus stimulation does not influence basal glucose metabolism or insulin sensitivity in patients with Parkinson's disease

    NARCIS (Netherlands)

    Lammers, Nicolette M.; Sondermeijer, Brigitte M.; Twickler, Th B. Marcel; de Bie, Rob M.; Ackermans, Mariëtte T.; Fliers, Eric; Schuurman, P. Richard; la Fleur, Susanne E.; Serlie, Mireille J.

    2014-01-01

    Animal studies have shown that central dopamine signaling influences glucose metabolism. As a first step to show this association in an experimental setting in humans, we studied whether deep brain stimulation (DBS) of the subthalamic nucleus (STN), which modulates the basal ganglia circuitry,

  6. Valsartan improves beta-cell function and insulin sensitivity in subjects with impaired glucose metabolism a randomized controlled trial

    NARCIS (Netherlands)

    van der Zijl, N.J.; Moors, C.C.M.; Goossens, G.H.; Hermans, M.M.H.; Blaak, E.E; Diamant, M.

    2011-01-01

    OBJECTIVE - Recently, the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research Trial demonstrated that treatment with the angiotensin receptor blocker (ARB) valsartan for 5 years resulted in a relative reduction of 14% in the incidence of type 2 diabetes in subjects with

  7. Short-Term Estrogen Replacement Effects on Insulin Sensitivity and Glucose Tolerance in At-Risk Cats for Feline Diabetes Mellitus.

    Directory of Open Access Journals (Sweden)

    Allison Wara

    Full Text Available Male domestic cats that are neutered and overweight are at an increased risk for developing a type-2-like diabetes mellitus. Beneficial effects of 17β-estradiol (E2 on glucose homeostasis may be lost with neutering and thereby account for increased diabetes risk. To evaluate this, adult male neutered overweight cats (n=6 were given daily E2 (1.0 μg/kg or vehicle (Vh; ethanol, 1.0 μL/kg in a single crossover trial of 14-day periods with a 7-day washout. The E2 and Vh were voluntarily ingested on food. The E2 dosage was determined in a pre-trial to significantly and transiently reduce food intake with no measurable change in plasma E2 concentration. During treatments, physical activity was assessed with collar-mounted accelerometers on days 9-11, and tests of intravenous insulin tolerance and intravenous glucose tolerance were conducted on days 13 and 14, respectively. Over the 14 days, E2 compared to Vh treatment reduced (p=0.03 food intake (- 22% but not enough to significantly reduce body weight; activity counts were not significantly changed. With E2 compared to Vh treatment, the late-phase plasma insulin response of the glucose tolerance test was less (p=0.03 by 31%, while glucose tolerance and insulin sensitivity indexes were not significantly changed. The results indicate that oral E2 at a dosage that moderately affects food intake may reduce insulin requirement for achieving glucose homeostasis in neutered male cats. Further investigation is needed to identify the mechanism underlying the E2 effect.

  8. High intensity interval exercise is an effective alternative to moderate intensity exercise for improving glucose tolerance and insulin sensitivity in adolescent boys.

    Science.gov (United States)

    Cockcroft, Emma J; Williams, Craig A; Tomlinson, Owen W; Vlachopoulos, Dimitris; Jackman, Sarah R; Armstrong, Neil; Barker, Alan R

    2015-11-01

    High-intensity interval exercise (HIIE) may offer a time efficient means to improve health outcomes compared to moderate-intensity exercise (MIE). This study examined the acute effect of HIIE compared to a work-matched bout of MIE on glucose tolerance, insulin sensitivity (IS), resting fat oxidation and exercise enjoyment in adolescent boys. Within-measures design with counterbalanced experimental conditions. Nine boys (14.2 ± 0.4 years) completed three conditions on separate days in a counterbalanced order: (1) HIIE; (2) work matched MIE, both on a cycle ergometer; and (3) rest (CON). An oral glucose tolerance test (OGTT) was performed after exercise or rest and the area under curve (AUC) responses for plasma [glucose] and [insulin] were calculated, and IS estimated (Cederholm index). Energy expenditure and fat oxidation were measured following the OGTT using indirect calorimetry. Exercise enjoyment was assessed using the Physical Activity Enjoyment Scale. The incremental AUC (iAUC) for plasma [glucose] was reduced following both MIE (-23.9%, P = 0.013, effect size [ES] = -0.64) and HIIE (-28.9%, P=0.008, ES = -0.84) compared to CON. The iAUC for plasma [insulin] was lower for HIIE (-24.2%, P = 0.021, ES = -0.71) and MIE (-29.1%, P = 0.012, ES = -0.79) compared to CON. IS increased by 11.2% after HIIE (P = 0.03, ES = 0.76) and 8.4% after MIE (P = 0.10, ES = 0.58). There was a trend for an increase in fat oxidation following HIIE (P = 0.097, ES = 0.70). Both HIIE and MIE were rated as equally enjoyable (P > 0.05, ES effective alternative to MIE for improving glucose tolerance and IS in adolescent boys immediately after exercise. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  9. Gravitropism in higher plant shoots. VI. Changing sensitivity to auxin in gravistimulated soybean hypocotyls

    Science.gov (United States)

    Rorabaugh, P. A.; Salisbury, F. B.

    1989-01-01

    Although the Cholodny-Went model of auxin redistribution has been used to explain the transduction phase of gravitropism for over 60 years, problems are apparent, especially with dicot stems. An alternative to an auxin gradient is a physiological gradient in which lower tissues of a horizontal stem become more sensitive than upper tissues to auxin already present. Changes in tissue sensitivity to auxin were tested by immersing marked Glycine max Merrill (soybean) hypocotyl sections in buffered auxin solutions (0, 10(-8) to 10(-2) molar indoleacetic acid) and observing bending and growth of upper and lower surfaces. The two surfaces of horizontal hypocotyl sections responded differently to the same applied auxin stimulus; hypocotyls bent up (lower half grew more) in buffer alone or in low auxin levels, but bent down (upper half grew more) in high auxin. Dose-response curves were evaluated with Michaelis-Menten kinetics, with auxin-receptor binding analogous to enzyme-substrate binding. Vmax for the lower half was usually greater than that for the upper half, which could indicate more binding sites in the lower half. Km of the upper half was always greater than that of the lower half (unmeasurably low), which could indicate that upper-half binding sites had a much lower affinity for auxin than lower-half sites. Dose-response curves were also obtained for sections scrubbed' (cuticle abraded) on top or bottom before immersion in auxin, and gravitropic memory' experiments of L. Brauner and A. Hagar (1958 Planta 51: 115-147) were duplicated. [1-14C]Indoleacetic acid penetration was equal into the two halves, and endogenous plus exogenously supplied (not radiolabeled) free auxin in the two halves (by gas chromatography-selected ion monitoring-mass spectrometry) was also equal. Thus, differential growth occurred without free auxin redistribution, contrary to Cholodny-Went but in agreement with a sensitivity model.

  10. Inhibition of glucose turnover by 3-bromopyruvate counteracts pancreatic cancer stem cell features and sensitizes cells to gemcitabine.

    Science.gov (United States)

    Isayev, Orkhan; Rausch, Vanessa; Bauer, Nathalie; Liu, Li; Fan, Pei; Zhang, Yiyao; Gladkich, Jury; Nwaeburu, Clifford C; Mattern, Jürgen; Mollenhauer, Martin; Rückert, Felix; Zach, Sebastian; Haberkorn, Uwe; Gross, Wolfgang; Schönsiegel, Frank; Bazhin, Alexandr V; Herr, Ingrid

    2014-07-15

    According to the cancer stem cell (CSC) hypothesis, the aggressive growth and early metastasis of pancreatic ductal adenocarcinoma (PDA) is due to the activity of CSCs, which are not targeted by current therapies. Otto Warburg suggested that the growth of cancer cells is driven by a high glucose metabolism. Here, we investigated whether glycolysis inhibition targets CSCs and thus may enhance therapeutic efficacy. Four established and 3 primary PDA cell lines, non-malignant cells, and 3 patient-tumor-derived CSC-enriched spheroidal cultures were analyzed by glucose turnover measurements, MTT and ATP assays, flow cytometry of ALDH1 activity and annexin positivity, colony and spheroid formation, western blotting, electrophoretic mobility shift assay, xenotransplantation, and immunohistochemistry. The effect of siRNA-mediated inhibition of LDH-A and LDH-B was also investigated. The PDA cells exhibited a high glucose metabolism, and glucose withdrawal or LDH inhibition by siRNA prevented growth and colony formation. Treatment with the anti-glycolytic agent 3-bromopyruvate almost completely blocked cell viability, self-renewal potential, NF-κB binding activity, and stem cell-related signaling and reverted gemcitabine resistance. 3-bromopyruvate was less effective in weakly malignant PDA cells and did not affect non-malignant cells, predicting minimal side effects. 3-bromopyruvate inhibited in vivo tumor engraftment and growth on chicken eggs and mice and enhanced the efficacy of gemcitabine by influencing the expression of markers of proliferation, apoptosis, self-renewal, and metastasis. Most importantly, primary CSC-enriched spheroidal cultures were eliminated by 3-bromopyruvate. These findings propose that CSCs may be specifically dependent on a high glucose turnover and suggest 3-bromopyruvate for therapeutic intervention.

  11. Inhibition of glucose turnover by 3-bromopyruvate counteracts pancreatic cancer stem cell features and sensitizes cells to gemcitabine

    OpenAIRE

    Isayev, Orkhan; Rausch, Vanessa; Bauer, Nathalie; Liu, Li; Fan, Pei; Zhang, Yiyao; Gladkich, Jury; Nwaeburu, Clifford C.; Mattern, Jürgen; Mollenhauer, Martin; Rückert, Felix; Zach, Sebastian; Haberkorn, Uwe; Gross, Wolfgang; Schönsiegel, Frank

    2014-01-01

    According to the cancer stem cell (CSC) hypothesis, the aggressive growth and early metastasis of pancreatic ductal adenocarcinoma (PDA) is due to the activity of CSCs, which are not targeted by current therapies. Otto Warburg suggested that the growth of cancer cells is driven by a high glucose metabolism. Here, we investigated whether glycolysis inhibition targets CSCs and thus may enhance therapeutic efficacy. Four established and 3 primary PDA cell lines, non-malignant cells, and 3 patien...

  12. Postoperative ocular higher-order aberrations and contrast sensitivity: femtosecond lenticule extraction versus pseudo small-incision lenticule extraction.

    Science.gov (United States)

    Tan, Deborah K L; Tay, Wan Ting; Chan, Cordelia; Tan, Donald T H; Mehta, Jodhbir S

    2015-03-01

    To evaluate and compare changes in contrast sensitivity and ocular higher-order aberrations (HOAs) after femtosecond lenticule extraction (FLEx) and pseudo small-incision lenticule extraction (SMILE). Singapore National Eye Centre, Singapore. Retrospective case series. Patients had femtosecond lenticule extraction (Group 1) or pseudo small-incision lenticule extraction (Group 2) between March 2010 and December 2011. The main outcome measures were manifest refraction, HOAs, and contrast sensitivity 1, 3, 6, and 12 months postoperatively. Fifty-two consecutive patients (102 eyes) were recruited, 21 patients (42 eyes) in Group 1 and the 31 patients (60 eyes) in Group 2. The uncorrected and corrected distance visual acuities were significantly better in Group 2 than in Group 1 at 12 months (P = .032). There was no significant increase in 3rd- or 4th-order aberrations at 1 year and no significant difference between the 2 groups preoperatively or postoperatively. At 1 year, there was a significant increase in mesopic contrast sensitivity in Group 2 at 1.5 cycles per degree (cpd) (P = .008) that was not found in Group 1, and photopic contrast sensitivity at 6.0 cpd was higher in Group 2 (P = .027). These results indicate that refractive lenticule extraction is safe and effective with no significant induction of HOAs or deterioration in contrast sensitivity at 1 year. Induction of HOAs was not significantly different between both variants of refractive lenticule extraction. However, there was significant improvement in photopic contrast sensitivity after pseudo small-incision lenticule extraction, which persisted through 1 year. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  13. Fe3O4 and metal-organic framework MIL-101(Fe) composites catalyze luminol chemiluminescence for sensitively sensing hydrogen peroxide and glucose.

    Science.gov (United States)

    Qian Tang, Xue; Dan Zhang, Yi; Wei Jiang, Zhong; Mei Wang, Dong; Zhi Huang, Cheng; Fang Li, Yuan

    2018-03-01

    In this work, Fe 3 O 4 and metal-organic framework MIL-101(Fe) composites (Fe 3 O 4 /MIL-101(Fe)) was demonstrated to possess excellent catalytic property to directly catalyze luminol chemiluminescence without extra oxidants. We utilized Fe 3 O 4 /MIL-101(Fe) to develop a ultra-sensitive quantitative analytical method for H 2 O 2 and glucose. The possible mechanism of the chemiluminescence reaction had been investigated. Under optimal conditions, the relative chemiluminescence intensity was linearly proportional to the logarithm of H 2 O 2 concentration in the range of 5-150nM with a limit of detection of 3.7nM (signal-to-noise ratio = 3), and glucose could be linearly detected in the range from 5 to 100nM and the detection limit was 4.9nM (signal-to-noise ratio = 3). Furthermore, the present approach was successfully applied to quantitative determination of H 2 O 2 in medical disinfectant and glucose in human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. l-Cysteine supplementation increases insulin sensitivity mediated by upregulation of GSH and adiponectin in high glucose treated 3T3-L1 adipocytes.

    Science.gov (United States)

    Achari, Arunkumar E; Jain, Sushil K

    2017-09-15

    RNA levels and GSH levels in GCLC knockdown adipocytes and LC supplementation up regulates GCLC, DsbA-L and GLUT-4 mRNA expression and GSH levels in GCLC knockdown cells. These results demonstrated that LC along with insulin increases GSH levels thereby improving adiponectin secretion and glucose utilization in adipocytes. This suggests that LC supplementation can increase insulin sensitivity and can be used as an adjuvant therapy for diabetes. Copyright © 2017. Published by Elsevier Inc.

  15. Consumption of meat is associated with higher fasting glucose and insulin concentrations regardless of glucose and insulin genetic risk scores: a meta-analysis of 50,345 Caucasians

    Science.gov (United States)

    Recent studies suggest that meat intake is associated with diabetes-related phenotypes. However, whether the associations of meat intake and glucose and insulin homeostasis are modified by genes related to glucose and insulin is unknown. We investigated the associations of meat intake and the intera...

  16. Consumption of meat is associated with higher fasting glucose and insulin concentrations regardless of glucose and insulin genetic risk scores: A meta-analysis of 50,345 Caucasians

    NARCIS (Netherlands)

    A.M. Fretts (Amanda M.); J.L. Follis (Jack ); J.A. Nettleton (Jennifer ); R.N. Lemaitre (Rozenn ); J.S. Ngwa; M.K. Wojczynski (Mary ); I.-P. Kalafati (Ioanna-Panagiota); T.V. Varga (Tibor V.); A.C. Frazier-Wood (Alexis C.); D.K. Houston (Denise); J. Lahti (Jari); U. Ericson (Ulrika); E.H. van den Hooven (Edith); V. Mikkilä (Vera); J.C. Kiefte-de Jong (Jessica); D. Mozaffarian (Dariush); K.M. Rice (Kenneth); F. Renström (Frida); K.E. North (Kari); N.M. McKeown (Nicola ); M.F. Feitosa (Mary Furlan); S. Kanoni (Stavroula); C.E. Smith (Caren); M. Garcia (Melissa); A.-M. Tiainen (Anna-Maija); E. Sonestedt (Emily); A. Manichaikul (Ani); F.J.A. van Rooij (Frank); M. Dimitriou (Maria); O. Raitakari (Olli); J.S. Pankow (James); L. Djoussé (Luc); M.A. Province (Mike); F.B. Hu (Frank); C.-Q. Lai (Chao-Qiang); M.F. Keller (Margaux); M.-M. Perälä (Mia-Maria); J.I. Rotter (Jerome I.); A. Hofman (Albert); M.J. Graff (Maud J.L.); M. Kähönen (Mika); K. Mukamal (Kenneth); I. Johansson (Ingegerd); J.M. Ordovas (Jose); Y. Liu (YongMei); S. Männistö (Satu); A.G. Uitterlinden (André); P. Deloukas (Panagiotis); I. Seppälä (Ilkka); B.M. Psaty (Bruce); L.A. Cupples (Adrienne); I.B. Borecki (Ingrid); P.W. Franks (Paul W.); D.K. Arnett (Donna); M.A. Nalls (Michael); K. Hagen (Knut); M. Orho-Melander (Marju); O.H. Franco (Oscar); T. Lehtimäki (Terho); G.V. Dedoussis (George); J.B. Meigs (James); D.S. Siscovick (David)

    2015-01-01

    textabstractBackground: Recent studies suggest that meat intake is associated with diabetes-related phenotypes. However, whether the associations of meat intake and glucose and insulin homeostasis are modified by genes related to glucose and insulin is unknown. Objective: We investigated the

  17. Use of Capillary Blood Samples Leads to Higher Parasitemia Estimates and Higher Diagnostic Sensitivity of Microscopic and Molecular Diagnostics of Malaria than Venous Blood Samples.

    Science.gov (United States)

    Mischlinger, Johannes; Pitzinger, Paul; Veletzky, Luzia; Groger, Mirjam; Zoleko-Manego, Rella; Adegnika, Ayola A; Agnandji, Selidji T; Lell, Bertrand; Kremsner, Peter G; Tannich, Egbert; Mombo-Ngoma, Ghyslain; Mordmüller, Benjamin; Ramharter, Michael

    2018-05-25

    Diagnosis of malaria is usually based on samples of peripheral blood. However, it is unclear whether capillary (CAP) or venous (VEN) blood samples provide better diagnostic performance. Quantitative differences of parasitemia between CAP and VEN blood and diagnostic performance characteristics were investigated. Patients were recruited between September 2015 and February 2016 in Gabon. Light microscopy and qPCR quantified parasitemia of paired CAP and VEN samples, whose preparation followed the exact same methodology. CAP and VEN performance characteristics using microscopy were evaluated against a qPCR gold-standard. Microscopy revealed a median (IQR) parasites/L of 495 (853,243) in CAP and 429 (524,074) in VEN samples manifesting in a +16.6% (p=0.04) higher CAPparasitemia compared with VENparasitemia. Concordantly, qPCR demonstrated that -0.278 (p=0.006) cycles were required for signal detection in CAP samples. CAPsensitivity of microscopy relative to the gold-standard was 81.5% (77.485.6%) versus VENsensitivity of 73.4% (68.878.1%), while CAPspecificity and VENspecificity were 91%. CAPsensitivity and VENsensitivity dropped to 63.3% and 45.9%, respectively for a sub-population of low-level parasitemias while specificities were 92%. CAP sampling leads to higher parasitemias compared to VEN sampling and improves diagnostic sensitivity. These findings may have important implications for routine diagnostics, research and elimination campaigns of malaria.

  18. Co3O4 based non-enzymatic glucose sensor with high sensitivity and reliable stability derived from hollow hierarchical architecture

    Science.gov (United States)

    Tian, Liangliang; He, Gege; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Yang, Cong; Chen, Yanling; Li, Lu

    2018-02-01

    Inspired by kinetics, the design of hollow hierarchical electrocatalysts through large-scale integration of building blocks is recognized as an effective approach to the achievement of superior electrocatalytic performance. In this work, a hollow, hierarchical Co3O4 architecture (Co3O4 HHA) was constructed using a coordinated etching and precipitation (CEP) method followed by calcination. The resulting Co3O4 HHA electrode exhibited excellent electrocatalytic activity in terms of high sensitivity (839.3 μA mM-1 cm-2) and reliable stability in glucose detection. The high sensitivity could be attributed to the large specific surface area (SSA), ample unimpeded penetration diffusion paths and high electron transfer rate originating from the unique two-dimensional (2D) sheet-like character and hollow porous architecture. The hollow hierarchical structure also affords sufficient interspace for accommodation of volume change and structural strain, resulting in enhanced stability. The results indicate that Co3O4 HHA could have potential for application in the design of non-enzymatic glucose sensors, and that the construction of hollow hierarchical architecture provides an efficient way to design highly active, stable electrocatalysts.

  19. The natural logarithm of zinc-α2-glycoprotein/HOMA-IR is a better predictor of insulin sensitivity than the product of triglycerides and glucose and the other lipid ratios.

    Science.gov (United States)

    Qu, Chunmei; Zhou, Xiaoxin; Yang, Gangyi; Li, Ling; Liu, Hua; Liang, Zerong

    2016-03-01

    The euglycemic-hyperinsulinemic clamp (EHC) is not available in most clinical settings and is costly, time consuming and invasive, and requires trained staff. Therefore, an accessible and inexpensive test to identify insulin resistance (IR) is needed. The aim of this study is to assess whether zinc-α2-glycoprotein (ZAG) index [Ln ZAG/homeostasis model assessment of IR (HOMA-IR)] is a better surrogate index for estimating IR or metabolic syndrome (MetS) compared with other surrogate indices. We performed a population-based cross-sectional study. Two hundred healthy subjects, 102 polycystic ovary syndrome (PCOS) patients, 97 newly diagnosed type 2 diabetes mellitus (nT2DM) and 84 impaired glucose tolerance (IGT) subjects were enrolled. The EHC was performed to identify IR. Circulating ZAG and adiponectin levels were determined by ELISA. The ZAG index was significantly lower in participants with IR including IGT, nT2DM and PCOS than in those without IR. In addition, subjects with MetS had lower ZAG indices and higher the product of fasting triglycerides and glucose (TyG) indices than those without MetS. The ZAG index showed a significantly stronger association with M values than the other surrogate indices, whereas the TyG index showed a stronger association with MetS. The optimal cutoff value of the ZAG index for detection of IR was 2.97 with a sensitivity of 88% and a specificity of 91%, whereas the optimal cutoff value of TyG index for detection of MetS was 4.90 with a sensitivity of 82% and a specificity of 86%. The ZAG index is a better marker than the other surrogate indices for identifying IR, whereas the TyG index has high sensitivity and specificity for identifying MetS. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Fluorescence ELISA for sensitive detection of ochratoxin A based on glucose oxidase-mediated fluorescence quenching of CdTe QDs

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yi [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047 (China); Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang 330047 (China); Huang, Xiaolin [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047 (China); Yu, Ruijin [College of Science, Northwest A& F University, Yangling, Shaanxi 712100 (China); Zhou, Yaofeng [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047 (China); Xiong, Yonghua, E-mail: yhxiongchen@163.com [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047 (China); Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang 330047 (China)

    2016-09-14

    The present study described a novel fluorescence enzyme-linked immunosorbent assay (ELISA) used to detect ochratoxin A (OTA) by using the glucose oxidase (GOx)-mediated fluorescence quenching of mercaptopropionic acid-capped CdTe quantum dots (MPA-QDs), in which GOx was used as an alternative to horseradish peroxidase (HRP) for the oxidization of glucose into hydrogen peroxide (H{sub 2}O{sub 2}) and gluconic acid. The MPA-QDs were used as a fluorescent signal output, whose fluorescence variation was extremely sensitive to the presence of H{sub 2}O{sub 2} or hydrogen ions in the solution. Under the optimized conditions, the proposed fluorescence ELISA demonstrated a good linear detection of OTA in corn extract from 2.4 pg mL{sup −1} to 625 pg mL{sup −1} with a limit of detection of 2.2 pg mL{sup −1}, which was approximately 15-fold lower than that of conventional HRP-based ELISA. Our developed fluorescence immunoassay was also similar to HRP-based ELISA in terms of selectivity, accuracy, and reproducibility. In summary, this study was the first to use the GOx-mediated fluorescence quenching of QDs in immunoassay to detect OTA, offering a new possibility for the analysis of other mycotoxins and biomolecules. - Highlights: • A novel fluorescence ELISA was first developed for the detection of OTA by using GOx-mediated fluorescence quenching of QDs. • The pH- and H{sub 2}O{sub 2}-sensitive MPA-capped CdTe QDs were used as a fluorescent signal output to improve the detection sensitivity. • This novel method open up a different vision to detect other mycotoxins and biomolecules.

  1. Fluorescence ELISA for sensitive detection of ochratoxin A based on glucose oxidase-mediated fluorescence quenching of CdTe QDs

    International Nuclear Information System (INIS)

    Liang, Yi; Huang, Xiaolin; Yu, Ruijin; Zhou, Yaofeng; Xiong, Yonghua

    2016-01-01

    The present study described a novel fluorescence enzyme-linked immunosorbent assay (ELISA) used to detect ochratoxin A (OTA) by using the glucose oxidase (GOx)-mediated fluorescence quenching of mercaptopropionic acid-capped CdTe quantum dots (MPA-QDs), in which GOx was used as an alternative to horseradish peroxidase (HRP) for the oxidization of glucose into hydrogen peroxide (H_2O_2) and gluconic acid. The MPA-QDs were used as a fluorescent signal output, whose fluorescence variation was extremely sensitive to the presence of H_2O_2 or hydrogen ions in the solution. Under the optimized conditions, the proposed fluorescence ELISA demonstrated a good linear detection of OTA in corn extract from 2.4 pg mL"−"1 to 625 pg mL"−"1 with a limit of detection of 2.2 pg mL"−"1, which was approximately 15-fold lower than that of conventional HRP-based ELISA. Our developed fluorescence immunoassay was also similar to HRP-based ELISA in terms of selectivity, accuracy, and reproducibility. In summary, this study was the first to use the GOx-mediated fluorescence quenching of QDs in immunoassay to detect OTA, offering a new possibility for the analysis of other mycotoxins and biomolecules. - Highlights: • A novel fluorescence ELISA was first developed for the detection of OTA by using GOx-mediated fluorescence quenching of QDs. • The pH- and H_2O_2-sensitive MPA-capped CdTe QDs were used as a fluorescent signal output to improve the detection sensitivity. • This novel method open up a different vision to detect other mycotoxins and biomolecules.

  2. Blood pressure is reduced and insulin sensitivity increased in glucose-intolerant, hypertensive subjects after 15 days of consuming high-polyphenol dark chocolate.

    Science.gov (United States)

    Grassi, Davide; Desideri, Giovambattista; Necozione, Stefano; Lippi, Cristina; Casale, Raffaele; Properzi, Giuliana; Blumberg, Jeffrey B; Ferri, Claudio

    2008-09-01

    Flavanols from chocolate appear to increase nitric oxide bioavailability, protect vascular endothelium, and decrease cardiovascular disease (CVD) risk factors. We sought to test the effect of flavanol-rich dark chocolate (FRDC) on endothelial function, insulin sensitivity, beta-cell function, and blood pressure (BP) in hypertensive patients with impaired glucose tolerance (IGT). After a run-in phase, 19 hypertensives with IGT (11 males, 8 females; 44.8 +/- 8.0 y) were randomized to receive isocalorically either FRDC or flavanol-free white chocolate (FFWC) at 100 g/d for 15 d. After a wash-out period, patients were switched to the other treatment. Clinical and 24-h ambulatory BP was determined by sphygmometry and oscillometry, respectively, flow-mediated dilation (FMD), oral glucose tolerance test, serum cholesterol and C-reactive protein, and plasma homocysteine were evaluated after each treatment phase. FRDC but not FFWC ingestion decreased insulin resistance (homeostasis model assessment of insulin resistance; P < 0.0001) and increased insulin sensitivity (quantitative insulin sensitivity check index, insulin sensitivity index (ISI), ISI(0); P < 0.05) and beta-cell function (corrected insulin response CIR(120); P = 0.035). Systolic (S) and diastolic (D) BP decreased (P < 0.0001) after FRDC (SBP, -3.82 +/- 2.40 mm Hg; DBP, -3.92 +/- 1.98 mm Hg; 24-h SBP, -4.52 +/- 3.94 mm Hg; 24-h DBP, -4.17 +/- 3.29 mm Hg) but not after FFWC. Further, FRDC increased FMD (P < 0.0001) and decreased total cholesterol (-6.5%; P < 0.0001), and LDL cholesterol (-7.5%; P < 0.0001). Changes in insulin sensitivity (Delta ISI - Delta FMD: r = 0.510, P = 0.001; Delta QUICKI - Delta FMD: r = 0.502, P = 0.001) and beta-cell function (Delta CIR(120) - Delta FMD: r = 0.400, P = 0.012) were directly correlated with increases in FMD and inversely correlated with decreases in BP (Delta ISI - Delta 24-h SBP: r = -0.368, P = 0.022; Delta ISI - Delta 24-h DBP r = -0.384, P = 0.017). Thus, FRDC

  3. Higher Magnesium Intake Is Associated with Lower Fasting Glucose and Insulin, with No Evidence of Interaction with Select Genetic Loci, in a Meta-Analysis of 15 CHARGE Consortium Studies1234

    Science.gov (United States)

    Hruby, Adela; Ngwa, Julius S.; Renström, Frida; Wojczynski, Mary K.; Ganna, Andrea; Hallmans, Göran; Houston, Denise K.; Jacques, Paul F.; Kanoni, Stavroula; Lehtimäki, Terho; Lemaitre, Rozenn N.; Manichaikul, Ani; North, Kari E.; Ntalla, Ioanna; Sonestedt, Emily; Tanaka, Toshiko; van Rooij, Frank J. A.; Bandinelli, Stefania; Djoussé, Luc; Grigoriou, Efi; Johansson, Ingegerd; Lohman, Kurt K.; Pankow, James S.; Raitakari, Olli T.; Riserus, Ulf; Yannakoulia, Mary; Zillikens, M. Carola; Hassanali, Neelam; Liu, Yongmei; Mozaffarian, Dariush; Papoutsakis, Constantina; Syvänen, Ann-Christine; Uitterlinden, André G.; Viikari, Jorma; Groves, Christopher J.; Hofman, Albert; Lind, Lars; McCarthy, Mark I.; Mikkilä, Vera; Mukamal, Kenneth; Franco, Oscar H.; Borecki, Ingrid B.; Cupples, L. Adrienne; Dedoussis, George V.; Ferrucci, Luigi; Hu, Frank B.; Ingelsson, Erik; Kähönen, Mika; Kao, W. H. Linda; Kritchevsky, Stephen B.; Orho-Melander, Marju; Prokopenko, Inga; Rotter, Jerome I.; Siscovick, David S.; Witteman, Jacqueline C. M.; Franks, Paul W.; Meigs, James B.; McKeown, Nicola M.; Nettleton, Jennifer A.

    2013-01-01

    Favorable associations between magnesium intake and glycemic traits, such as fasting glucose and insulin, are observed in observational and clinical studies, but whether genetic variation affects these associations is largely unknown. We hypothesized that single nucleotide polymorphisms (SNPs) associated with either glycemic traits or magnesium metabolism affect the association between magnesium intake and fasting glucose and insulin. Fifteen studies from the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium provided data from up to 52,684 participants of European descent without known diabetes. In fixed-effects meta-analyses, we quantified 1) cross-sectional associations of dietary magnesium intake with fasting glucose (mmol/L) and insulin (ln-pmol/L) and 2) interactions between magnesium intake and SNPs related to fasting glucose (16 SNPs), insulin (2 SNPs), or magnesium (8 SNPs) on fasting glucose and insulin. After adjustment for age, sex, energy intake, BMI, and behavioral risk factors, magnesium (per 50-mg/d increment) was inversely associated with fasting glucose [β = −0.009 mmol/L (95% CI: −0.013, −0.005), P magnesium-related SNP or interaction between any SNP and magnesium reached significance after correction for multiple testing. However, rs2274924 in magnesium transporter-encoding TRPM6 showed a nominal association (uncorrected P = 0.03) with glucose, and rs11558471 in SLC30A8 and rs3740393 near CNNM2 showed a nominal interaction (uncorrected, both P = 0.02) with magnesium on glucose. Consistent with other studies, a higher magnesium intake was associated with lower fasting glucose and insulin. Nominal evidence of TRPM6 influence and magnesium interaction with select loci suggests that further investigation is warranted. PMID:23343670

  4. Glycine post-synthetic modification of MIL-53(Fe) metal-organic framework with enhanced and stable peroxidase-like activity for sensitive glucose biosensing.

    Science.gov (United States)

    Dong, Wenfei; Yang, Liaoyuan; Huang, Yuming

    2017-05-15

    A facile and rapid post-synthetic strategy was proposed to prepare a glycine functionalized MIL-53(Fe), namely glycine-MIL-53(Fe), by a simple mixing of water dispersible MIL-53(Fe) and glycine. The FT-IR, SEM, XRD and zeta potential were used to characterize the glycine-MIL-53(Fe). The result showed that glycine post-synthetic modification of MIL-53(Fe) did not change in the morphology and crystal structure of MIL-53(Fe). Interestingly, compared with MIL-53(Fe), the glycine-MIL-53(Fe) exhibits an enhanced peroxidase-like activity, which could catalyze the oxidation of TMB by H 2 O 2 to produce an intensive color reaction. Kinetic analysis indicated that the K m of glycine-MIL-53(Fe) for TMB was one-tenth of that of MIL-53(Fe). The glycine-MIL-53(Fe) as peroxidase mimetic displays better stability under alkaline or acidic conditions than MIL-53(Fe). The good performance of glycine-MIL-53(Fe) over MIL-53(Fe) may be attributed to the increase of affinity between TMB and the glycine-MIL-53(Fe). With these characteristics, a simple and sensitive method was developed for the detection of H 2 O 2 and glucose. The linear detection range for H 2 O 2 is 0.10-10μM with a detection limit of 49nM, and glucose could be linearly detected in the range from 0.25 to 10μM with a detection limit of 0.13μM. The proposed method was successfully used for glucose detection in human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Low-volume high-intensity swim training is superior to high-volume low-intensity training in relation to insulin sensitivity and glucose control in inactive middle-aged women

    DEFF Research Database (Denmark)

    Connolly, Luke J; Nordsborg, Nikolai Baastrup; Nyberg, Michael Permin

    2016-01-01

    recovery periods and LIT swam continuously for 1 h at low intensity (average HR = 73 ± 3 % HRmax). Fasting blood samples were taken and an oral glucose tolerance test (OGTT) was conducted pre- and post-intervention. RESULTS: After HIT, resting plasma [insulin] was lowered (17 ± 34 %; P ... adhesion molecule 1 had decreased (P intermittent swimming is an effective and time-efficient training strategy for improving insulin sensitivity, glucose control and biomarkers of vascular function...

  6. PubMed had a higher sensitivity than Ovid-MEDLINE in the search for systematic reviews.

    Science.gov (United States)

    Katchamart, Wanruchada; Faulkner, Amy; Feldman, Brian; Tomlinson, George; Bombardier, Claire

    2011-07-01

    To compare the performance of Ovid-MEDLINE vs. PubMed for identifying randomized controlled trials of methotrexate (MTX) in patients with rheumatoid arthritis (RA). We created search strategies for Ovid-MEDLINE and PubMed for a systematic review of MTX in RA. Their performance was evaluated using sensitivity, precision, and number needed to read (NNR). Comparing searches in Ovid-MEDLINE vs. PubMed, PubMed retrieved more citations overall than Ovid-MEDLINE; however, of the 20 citations that met eligibility criteria for the review, Ovid-MEDLINE retrieved 17 and PubMed 18. The sensitivity was 85% for Ovid-MEDLINE vs. 90% for PubMed, whereas the precision and NNR were comparable (precision: 0.881% for Ovid-MEDLINE vs. 0.884% for PubMed and NNR: 114 for Ovid-MEDLINE vs. 113 for PubMed). In systematic reviews of RA, PubMed has higher sensitivity than Ovid-MEDLINE with comparable precision and NNR. This study highlights the importance of well-designed database-specific search strategies. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. Highly sensitive and wide-range nonenzymatic disposable glucose sensor based on a screen printed carbon electrode modified with reduced graphene oxide and Pd-CuO nanoparticles

    International Nuclear Information System (INIS)

    Dhara, Keerthy; Thiagarajan, Ramachandran; Thekkedath, Gopalakrishnan Satheesh Babu; Nair, Bipin G.

    2015-01-01

    A nanocomposite consisting of reduced graphene oxide decorated with palladium-copper oxide nanoparticles (Pd-CuO/rGO) was synthesized by single-step chemical reduction. The morphology and crystal structure of the nanocomposite were characterized by field-emission scanning electron microscopy, high resolution transmission electron microscopy and X-ray diffraction analysis. A 3-electrode system was fabricated by screen printing technology and the Pd-CuO/rGO nanocomposite was drop cast on the carbon working electrode. The catalytic activity towards glucose in 0.2 M NaOH solutions was analyzed by linear sweep voltammetry and amperometry. The steady state current obtained at a constant potential of +0.6 V (vs. Ag/AgCl) showed the modified electrode to possess a wide analytical range (6 μM to 22 mM), a rather low limit of detection (30 nM), excellent sensitivity (3355 μA∙mM −1 ∙cm −2 ) and good selectivity over commonly interfering species and other sugars including fructose, sucrose and lactose. The sensor was successfully employed to the determination of glucose in blood serum. (author)

  8. Prevalence of Non-responders for Glucose Control Markers after 10 Weeks of High-Intensity Interval Training in Adult Women with Higher and Lower Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Cristian Álvarez

    2017-07-01

    Full Text Available Background: Exercise training improves performance and biochemical parameters on average, but wide interindividual variability exists, with individuals classified as responders (R or non-responders (NRs, especially between populations with higher or lower levels of insulin resistance. This study assessed the effects of high-intensity interval training (HIIT and the prevalence of NRs in adult women with higher and lower levels of insulin resistance.Methods: Forty adult women were assigned to a HIIT program, and after training were analyzed in two groups; a group with higher insulin resistance (H-IR, 40 ± 6 years; BMI: 29.5 ± 3.7 kg/m2; n = 20 and a group with lower insulin resistance (L-IR, 35 ± 9 years; 27.8 ± 2.8 kg/m2; n = 20. Anthropometric, cardiovascular, metabolic, and performance variables were measured at baseline and after 10 weeks of training.Results: There were significant training-induced changes [delta percent (Δ%] in fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR scores in the H-IR group (−8.8, −26.5, −32.1%, p < 0.0001, whereas no significant changes were observed in the L-IR. Both groups showed significant pre-post changes in other anthropometric variables [waist circumference (−5.2, p < 0.010, and −3.8%, p = 0.046 and tricipital (−13.3, p < 0.010, and −13.6%, p < 0.0001, supra-iliac (−19.4, p < 0.0001, and −13.6%, p < 0.0001, and abdominal (−18.2, p < 0.0001, and −15.6%, p < 0.010 skinfold measurements]. Systolic blood pressure decreased significantly only in the L-IR group (−3.2%, p < 0.010. Both groups showed significant increases in 1RMLE (+12.9, p < 0.010, and +14.7%, p = 0.045. There were significant differences in the prevalence of NRs between the H-IR and L-IR groups for fasting glucose (25 vs. 95%, p < 0.0001 and fasting insulin (p = 0.025 but not for HOMA-IR (25 vs. 45%, p = 0.185.Conclusion: Independent of the “magnitude” of the

  9. Tc(V)-DMS tumor localization mechanism: a pH-sensitive Tc(V)-DMS-enhanced target/nontarget ratio by glucose-mediated acidosis

    International Nuclear Information System (INIS)

    Horiuchi, Kazuko; Saji, Hideo; Yokoyama, Akira

    1998-01-01

    Since the conception of the pentavalent technetium polynuclear complex of dimercaptosuccinic acid, Tc(V)-DMS, a great number of papers published on its clinical applicability forced us to question ''how tumor tissue appropriates the Tc(V)-DMS.'' Preliminary in vitro studies with Ehrlich ascites tumor cells (EATC) indicated the pH-sensitive character of this tumor agent. From this finding and the well-established notion that malignant tumors are more acidic than normal tissue, the in vivo correlation of Tc(V)-DMS accumulation in tumor tissue with its tissue acidification was considered of interest. The systemic lowering of tumor tissue pH by the stimulation of aerobic glycolysis has been well reported. In the present paper, the response of Tc(V)-DMS tumor accumulation to acidification induced by the glucose administration was explored in EATC-bearing mice. Measurement of tumor tissue pH was carried out by direct microelectrode technique and by histochemical umbelliferone technique in tumor tissue excised from EATC bearing mice. The regional acidity distribution is correlated with the regional radioactivity distribution registered by autoradiography. Evidence related to the pH sensitiveness of Tc(V)-DMS in response to glycolytic acidification was gathered; the pH measurement and the in vivo biodistribution of the double-tracer macroautoradiography with C-14 deoxyglucose (C-14-DG) demonstrated that the regional tissue distribution of Tc(V)-DMS was superimposed to that of C-14-DG. The glucose interventional modality offers the premier foundation for the interpretation of Tc(V)-DMS accumulation in diagnostic studies of malignant tumors

  10. Inhibition of DNA repair by whole body irradiation induced nitric oxide leads to higher radiation sensitivity in lymphocytes

    International Nuclear Information System (INIS)

    Sharma, Deepak; Santosh Kumar, S.; Raghu, Rashmi; Maurya, D.K.; Sainis, K.B.

    2007-01-01

    Full text: It is well accepted that the sensitivity of mammalian cells is better following whole body irradiation (WBI) as compared to that following in vitro irradiation. However, the underlying mechanisms are not well understood. Following WBI, the lipid peroxidation and cell death were significantly higher in lymphocytes as compared to that in vitro irradiated lymphocytes. Further, WBI treatment of tumor bearing mice resulted in a significantly higher inhibition of EL-4 cell proliferation as compared to in vitro irradiation of EL-4 cells. The DNA repair was significantly slower in lymphocytes obtained from WBI treated mice as compared to that in the cells exposed to same dose of radiation in vitro. Generation of nitric oxide following irradiation and also its role in inhibition of DNA repair have been reported, hence, its levels were estimated under both WBI and in vitro irradiation conditions. Nitric oxide levels were significantly elevated in the plasma of WBI treated mice but not in the supernatant of in vitro irradiated cells. Addition of sodium nitroprusside (SNP), a nitric oxide donor to in vitro irradiated cells inhibited the repair of DNA damage and sensitized cells to undergo cell death. It also enhanced the radiation-induced functional impairment of lymphocytes as evinced from suppression of mitogen-induced IL-2, IFN-γ and bcl-2 mRNA expression. Administration of N G -nitro-L-arginine-methyl-ester(L-NAME), a nitric oxide synthase inhibitor, to mice significantly protected lymphocytes against WBI-induced DNA damage and inhibited in vivo radiation-induced production of nitric oxide. Our results indicated that nitric oxide plays a role in the higher radiosensitivity of lymphocytes in vivo by inhibiting repair of DNA damage

  11. Optimization of economic load dispatch of higher order general cost polynomials and its sensitivity using modified particle swarm optimization

    International Nuclear Information System (INIS)

    Saber, Ahmed Yousuf; Chakraborty, Shantanu; Abdur Razzak, S.M.; Senjyu, Tomonobu

    2009-01-01

    This paper presents a modified particle swarm optimization (MPSO) for constrained economic load dispatch (ELD) problem. Real cost functions are more complex than conventional second order cost functions when multi-fuel operations, valve-point effects, accurate curve fitting, etc., are considering in deregulated changing market. The proposed modified particle swarm optimization (PSO) consists of problem dependent variable number of promising values (in velocity vector), unit vector and error-iteration dependent step length. It reliably and accurately tracks a continuously changing solution of the complex cost function and no extra concentration/effort is needed for the complex higher order cost polynomials in ELD. Constraint management is incorporated in the modified PSO. The modified PSO has balance between local and global searching abilities, and an appropriate fitness function helps to converge it quickly. To avoid the method to be frozen, stagnated/idle particles are reset. Sensitivity of the higher order cost polynomials is also analyzed visually to realize the importance of the higher order cost polynomials for the optimization of ELD. Finally, benchmark data sets and methods are used to show the effectiveness of the proposed method. (author)

  12. Parameters of glucose metabolism and the aging brain

    DEFF Research Database (Denmark)

    Akintola, Abimbola A; van den Berg, Annette; Altmann-Schneider, Irmhild

    2015-01-01

    Given the concurrent, escalating epidemic of diabetes mellitus and neurodegenerative diseases, two age-related disorders, we aimed to understand the relation between parameters of glucose metabolism and indices of pathology in the aging brain. From the Leiden Longevity Study, 132 participants (mean...... age 66 years) underwent a 2-h oral glucose tolerance test to assess glucose tolerance (fasted and area under the curve (AUC) glucose), insulin sensitivity (fasted and AUC insulin and homeostatic model assessment of insulin sensitivity (HOMA-IS)) and insulin secretion (insulinogenic index). 3-T brain...... significant associations were found for white matter. Thus, while higher glucose was associated with macro-structural damage, impaired insulin action was associated more strongly with reduced micro-structural brain parenchymal homogeneity. These findings offer some insight into the association between...

  13. Highly Sensitive Detection of Glucose by a "Turn-Off-On" Fluorescent Probe Using Gadolinium-Doped Carbon Dots and Carbon Microparticles.

    Science.gov (United States)

    Hu, Meixin; Qi, Jianrong; Ruan, Jing; Shen, Guangxia

    2018-06-01

    Carbon dots, as a potential substitute for semiconductor quantum dots, have drawn great interest in recent years. The preparation of fluorescent carbon dots has been made easy with many significant advances, but the complicated purifying processes, low quantum yield, and blue emission wavelength still limit its wider application in biosensors, biomedicine, and photonic devices. Here we report a strategy to synthesis Gd-doped carbon dots (Gd-Cdots) of super-high quantum yield with a microwave assisted hydrothermal method. The Gd-Cdots, with a diameter of 47∼8 nm, can be purified easily with conventional centrifugal techniques. Carbon microparticles (CMPs) have also been synthesized with a similar procedure. Meanwhile, we demonstrated a novel "turn-off-on" fluorescent biosensor, which has been developed for highly sensitive detection of glucose using Gd-doped carbon dots as probes. The proposed biosensor has exhibited low-cost and non-toxic properties, with high sensitivity and good specificity. In addition, the results in real blood samples further confirmed it as a promising application in diabetes diagnosis.

  14. Glucose aided synthesis of molybdenum sulfide/carbon nanotubes composites as counter electrode for high performance dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Yue, Gentian; Zhang, Weifeng; Wu, Jihuai; Jiang, Qiwei

    2013-01-01

    Graphical abstract: - Highlights: • The glucose aided (G-A) preparation of MoS 2 /CNTs composites were employed as CE in Pt-free DSSC. • The (G-A) MoS 2 /CNTs* CE showed the low R ct of 1.77 Ω cm 2 . • The efficiency of the DSSC reached 7.92% based on the (G-A) MoS 2 /CNTs* CE. - Abstract: In our present study, the composites of molybdenum disulfide/carbon nanotubes (MoS 2 /CNTs) were synthesized with glucose aided (G-A) by using an in situ hydrothermal route, and proposed as counter electrode (CE) catalyst in the dye-sensitized solar cells (DSSCs) for enhancing electrocatalytic activity toward the reduction of triiodide. The MoS 2 /CNTs composites with tentacle-like structure were confirmed by using the scanning and transmission electron microscopy. The superior structural characteristics including large active surface area and particularly the unique tentacle-like nanostructure along with 3D large interconnected interstitial volume guaranteed fast mass transport for the electrolyte, and enabled the (G-A) MoS 2 /CNTs CE to speed up the reduction of triiodide to iodide. The extensive electrochemical studies by the cyclic voltammetry, electrochemical impedence spectroscopy and Tafel measurements indicated that the (G-A) MoS 2 /CNTs CE possessed superior electrocatalytic activity, great electrochemical stability and impressive low charge transfer resistance on the electrolyte|electrode interface (1.77 Ω cm 2 ) in the triiodide/iodide system compared to the pristine MoS 2 , MoS 2 /C and sputtered Pt CEs. The DSSC assembled with the novel (G-A) MoS 2 /CNTs CE exhibited high power conversion efficiency of 7.92% under the illumination of 100 mW cm −2 , comparable to that of the DSSC with the Pt electrode (7.11%)

  15. Studies of the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) gene in relation to insulin sensitivity among glucose tolerant caucasians

    DEFF Research Database (Denmark)

    Ek, J; Andersen, G; Urhammer, S A

    2001-01-01

    We examined whether the Pro12-Ala polymorphism of the human peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) gene was related to altered insulin sensitivity among glucose-tolerant subjects or a lower accumulated incidence or prevalence of IGT and Type II (non-insulin-dependent) dia......-insulin-dependent) diabetes mellitus among Scandinavian Caucasians....

  16. A natively paired antibody library yields drug leads with higher sensitivity and specificity than a randomly paired antibody library.

    Science.gov (United States)

    Adler, Adam S; Bedinger, Daniel; Adams, Matthew S; Asensio, Michael A; Edgar, Robert C; Leong, Renee; Leong, Jackson; Mizrahi, Rena A; Spindler, Matthew J; Bandi, Srinivasa Rao; Huang, Haichun; Tawde, Pallavi; Brams, Peter; Johnson, David S

    2018-04-01

    Deep sequencing and single-chain variable fragment (scFv) yeast display methods are becoming more popular for discovery of therapeutic antibody candidates in mouse B cell repertoires. In this study, we compare a deep sequencing and scFv display method that retains native heavy and light chain pairing with a related method that randomly pairs heavy and light chain. We performed the studies in a humanized mouse, using interleukin 21 receptor (IL-21R) as a test immunogen. We identified 44 high-affinity binder scFv with the native pairing method and 100 high-affinity binder scFv with the random pairing method. 30% of the natively paired scFv binders were also discovered with the randomly paired method, and 13% of the randomly paired binders were also discovered with the natively paired method. Additionally, 33% of the scFv binders discovered only in the randomly paired library were initially present in the natively paired pre-sort library. Thus, a significant proportion of "randomly paired" scFv were actually natively paired. We synthesized and produced 46 of the candidates as full-length antibodies and subjected them to a panel of binding assays to characterize their therapeutic potential. 87% of the antibodies were verified as binding IL-21R by at least one assay. We found that antibodies with native light chains were more likely to bind IL-21R than antibodies with non-native light chains, suggesting a higher false positive rate for antibodies from the randomly paired library. Additionally, the randomly paired method failed to identify nearly half of the true natively paired binders, suggesting a higher false negative rate. We conclude that natively paired libraries have critical advantages in sensitivity and specificity for antibody discovery programs.

  17. High-field modulated ion-selective field-effect-transistor (FET) sensors with sensitivity higher than the ideal Nernst sensitivity.

    Science.gov (United States)

    Chen, Yi-Ting; Sarangadharan, Indu; Sukesan, Revathi; Hseih, Ching-Yen; Lee, Geng-Yen; Chyi, Jen-Inn; Wang, Yu-Lin

    2018-05-29

    Lead ion selective membrane (Pb-ISM) coated AlGaN/GaN high electron mobility transistors (HEMT) was used to demonstrate a whole new methodology for ion-selective FET sensors, which can create ultra-high sensitivity (-36 mV/log [Pb 2+ ]) surpassing the limit of ideal sensitivity (-29.58 mV/log [Pb 2+ ]) in a typical Nernst equation for lead ion. The largely improved sensitivity has tremendously reduced the detection limit (10 -10  M) for several orders of magnitude of lead ion concentration compared to typical ion-selective electrode (ISE) (10 -7  M). The high sensitivity was obtained by creating a strong filed between the gate electrode and the HEMT channel. Systematical investigation was done by measuring different design of the sensor and gate bias, indicating ultra-high sensitivity and ultra-low detection limit obtained only in sufficiently strong field. Theoretical study in the sensitivity consistently agrees with the experimental finding and predicts the maximum and minimum sensitivity. The detection limit of our sensor is comparable to that of Inductively-Coupled-Plasma Mass Spectrum (ICP-MS), which also has detection limit near 10 -10  M.

  18. Insulin dynamics and biochemical markers for predicting impaired glucose tolerance in obese Thai youth.

    Science.gov (United States)

    Tirabanchasak, Sirapassorn; Siripunthana, Sukumarn; Supornsilchai, Vichit; Wacharasindhu, Suttipong; Sahakitrungruang, Taninee

    2015-09-01

    Subjects with impaired glucose tolerance (IGT) are at risk for type 2 diabetes mellitus (T2DM) and cardiovascular disease. The predictors of IGT in obese youth are not well described. We studied 115 obese Thai children who underwent an oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were calculated for assessment of β-cell function. Hemoglobin A1c (HbA1c), lipid profile, and clinical parameters were also used to determine predictors of IGT. We found that three patients had T2DM and 30 subjects had IGT. IGT patients had significantly higher fasting glucose (FG), 1-h postload glucose, 2-h postload insulin, and lower whole-body insulin sensitivity indices than in normal glucose tolerance subjects whereas other indices were comparable. By ROC curve analyses, 1-h postload glucose was the best predictor of IGT, but FG or HbA1c represented a poor diagnostic tool for prediabetes screening. Subjects with 1-h OGTT glucose > 155 mg/dL had significantly lower high-density lipoprotein levels, lower insulin sensitivity, and more insulin resistance than those with 1-h postload glucose of ≤ 155 mg/dL. Abnormal glucose tolerance is highly prevalent in obese Thai youth. Several fasting indices and HbA1c fail to predict IGT. An 1-h OGTT glucose of > 155 mg/dL appears to be more associated with adverse insulin dynamics and metabolic profile than 2-h postload glucose.

  19. Skeletal muscle glucose uptake during exercise

    DEFF Research Database (Denmark)

    Rose, Adam John; Richter, Erik

    2005-01-01

    The increase in skeletal muscle glucose uptake during exercise results from a coordinated increase in rates of glucose delivery (higher capillary perfusion), surface membrane glucose transport, and intracellular substrate flux through glycolysis. The mechanism behind the movement of GLUT4...

  20. Construction of near-infrared photonic crystal glucose-sensing materials for ratiometric sensing of glucose in tears.

    Science.gov (United States)

    Hu, Yumei; Jiang, Xiaomei; Zhang, Laiying; Fan, Jiao; Wu, Weitai

    2013-10-15

    Noninvasive monitoring of glucose in tears is highly desirable in tight glucose control. The polymerized crystalline colloidal array (PCCA) that can be incorporated into contact lens represents one of the most promising materials for noninvasive monitoring of glucose in tears. However, low sensitivity and slow time response of the PCCA reported in previous arts has limited its clinical utility. This paper presents a new PCCA, denoted as NIR-PCCA, comprising a CCA of glucose-responsive sub-micrometered poly(styrene-co-acrylamide-co-3-acrylamidophenylboronic acid) microgels embedded within a slightly positive charged hydrogel matrix of poly(acrylamide-co-2-(dimethylamino)ethyl acrylate). This newly designed NIR-PCCA can reflect near-infrared (NIR) light, whose intensity (at 1722 nm) would decrease evidently with increasing glucose concentration over the physiologically relevant range in tears. The lowest glucose concentration reliably detectable was as low as ca. 6.1 μg/dL. The characteristic response time τ(sensing) was 22.1±0.2s when adding glucose to 7.5 mg/dL, and the higher the glucose concentration is, the faster the time response. Such a rationally designed NIR-PCCA is well suited for ratiometric NIR sensing of tear glucose under physiological conditions, thereby likely to bring this promising glucose-sensing material to the forefront of analytical devices for diabetes. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Fast synthesis of porous NiCo{sub 2}O{sub 4} hollow nanospheres for a high-sensitivity non-enzymatic glucose sensor

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wei; Cao, Yang; Chen, Yong [State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering, Hainan University, Haikou 570228 (China); Peng, Juan; Lai, Xiaoyong [Laboratory Cultivation Base of Natural Gas Conversion, School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021 (China); Tu, Jinchun, E-mail: tujinchun@hainu.edu.cn [State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering, Hainan University, Haikou 570228 (China)

    2017-02-28

    Highlights: • Porous NiCo{sub 2}O{sub 4} hollow nanospheres were synthesized via a facile “CEP” approach and the synthesis mechanism was discussed. • The NiCo{sub 2}O{sub 4} hollow nanospheres possess superior electron-transfer capability and electrocatalytic activity. • The sensitivity is as high as 1917 μA·mM{sup −1}·cm{sup −2} and the detection limit is as low as 0.6 μM (S/N = 3). - Abstract: In this paper, we report the fast synthesis of porous NiCo{sub 2}O{sub 4} hollow nanospheres via a polycrystalline Cu{sub 2}O-templated route based on the elaborately designed “coordinating etching and precipitating” process. The composition and morphology of the porous NiCo{sub 2}O{sub 4} hollow nanospheres were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The electron-transfer capability and electrocatalytic activity of the materials were investigated by electrochemical impedance spectroscopy and cyclic voltammetry. NiCo{sub 2}O{sub 4} was endowed with superior electron-transfer capability, large surface area, and abundant intrinsic redox couples of Ni{sup 2+}/Ni{sup 3+} and Co{sup 2+}/Co{sup 3+} ions; thus, the modified electrode exhibited excellent glucose-sensing properties, with a high sensitivity of 1917 μA·mM{sup −1}·cm{sup −2} at a low concentration, a good linear range from 0.01 mM to 0.30 mM and from 0.30 mM to 2.24 mM, and a low detection limit of 0.6 μM (S/N = 3).

  2. Synthesis and evaluation of temperature- and glucose-sensitive nanoparticles based on phenylboronic acid and N-vinylcaprolactam for insulin delivery

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jun-zi [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620 (China); Bremner, David H. [School of Science, Engineering and Technology, Kydd Building, Abertay University, Dundee DD1 1HG, Scotland (United Kingdom); Li, He-yu; Sun, Xiao-zhu [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620 (China); Zhu, Li-Min, E-mail: lzhu@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620 (China)

    2016-12-01

    Poly N-vinylcaprolactam-co-acrylamidophenylboronic acid p(NVCL-co-AAPBA) was prepared from N-vinylcaprolactam (NVCL) and 3-acrylamidophenylboronic acid (AAPBA), using 2,2-azobisisobutyronitrile (AIBN) as initiator. The synthesis and structure of the polymer were examined by Fourier Transform infrared spectroscopy (FT-IR) and {sup 1}H-NMR. Dynamic light scattering (DLS), lower critical solution temperature (LCST) and transmission electron microscopy (TEM) were utilized to characterize the nanoparticles, CD spectroscopy was used to determine if there were any changes to the conformation of the insulin, and cell and animal toxicity were also investigated. The prepared nanoparticles were found to be monodisperse submicron particles and were glucose- and temperature-sensitive. In addition, the nanoparticles have good insulin-loading characteristics, do not affect the conformation of the insulin and show low-toxicity to cells and animals. These p(NVCL-co-AAPBA) nanoparticles may have some value for insulin or other hypoglycemic protein delivery. - Highlights: • A comprehensive study of a nanoparticles may have some value for insulin or other hypoglycemic protein delivery. • p(NVCL-co-AAPBA)'s synthetic method is simple, convenient to carry out. • NVCL is low toxic and safe. • The evaluation of acute toxicity and chronic toxicity is the most highlight.

  3. Three-Dimensional Porous Nickel Frameworks Anchored with Cross-Linked Ni(OH)2 Nanosheets as a Highly Sensitive Nonenzymatic Glucose Sensor.

    Science.gov (United States)

    Mao, Weiwei; He, Haiping; Sun, Pengcheng; Ye, Zhizhen; Huang, Jingyun

    2018-05-02

    A facile and scalable in situ microelectrolysis nanofabrication technique is developed for preparing cross-linked Ni(OH) 2 nanosheets on a novel three-dimensional porous nickel template (Ni(OH) 2 @3DPN). For the constructed template, the porogen of NaCl particles not only induces a self-limiting surficial hot corrosion to claim the "start engine stop" mechanism but also serves as the primary battery electrolyte to greatly accelerate the growth of Ni(OH) 2 . As far as we know, the microelectrolysis nanofabrication is superior to the other reported Ni(OH) 2 synthesis methods due to the mild condition (60 °C, 6 h, NaCl solution, ambient environment) and without any post-treatment. The integrated Ni(OH) 2 @3DPN electrode with a highly suitable microstructure and a porous architecture implies a potential application in electrochemistry. As a proof-of-concept demonstration, the electrode was employed for nonenzymatic glucose sensing, which exhibits an outstanding sensitivity of 2761.6 μA mM -1 cm -2 ranging from 0.46 to 2100 μM, a fast response, and a low detection limit. The microelectrolysis nanofabrication is a one-step, binder-free, entirely green, and therefore it has a distinct advantage to improve clean production and reduce energy consumption.

  4. Expression profiling analysis: Uncoupling protein 2 deficiency improves hepatic glucose, lipid profiles and insulin sensitivity in high-fat diet-fed mice by modulating expression of genes in peroxisome proliferator-activated receptor signaling pathway.

    Science.gov (United States)

    Zhou, Mei-Cen; Yu, Ping; Sun, Qi; Li, Yu-Xiu

    2016-03-01

    Uncoupling protein 2 (UCP2), which was an important mitochondrial inner membrane protein associated with glucose and lipid metabolism, widely expresses in all kinds of tissues including hepatocytes. The present study aimed to explore the impact of UCP2 deficiency on glucose and lipid metabolism, insulin sensitivity and its effect on the liver-associated signaling pathway by expression profiling analysis. Four-week-old male UCP2-/- mice and UCP2+/+ mice were randomly assigned to four groups: UCP2-/- on a high-fat diet, UCP2-/- on a normal chow diet, UCP2+/+ on a high-fat diet and UCP2+/+ on a normal chow diet. The differentially expressed genes in the four groups on the 16th week were identified by Affymetrix gene array. The results of intraperitoneal glucose tolerance test and insulin tolerance showed that blood glucose and β-cell function were improved in the UCP2-/- group on high-fat diet. Enhanced insulin sensitivity was observed in the UCP2-/- group. The differentially expressed genes were mapped to 23 pathways (P high-fat diet. The upregulation of genes in the PPAR signaling pathway could explain our finding that UCP2 deficiency ameliorated insulin sensitivity. The manipulation of UCP2 protein expression could represent a new strategy for the prevention and treatment of diabetes.

  5. Glucose Sensing

    CERN Document Server

    Geddes, Chris D

    2006-01-01

    Topics in Fluorescence Spectroscopy, Glucose Sensing is the eleventh volume in the popular series Topics in Fluorescence Spectroscopy, edited by Drs. Chris D. Geddes and Joseph R. Lakowicz. This volume incorporates authoritative analytical fluorescence-based glucose sensing reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. Glucose Sensing is an essential reference for any lab working in the analytical fluorescence glucose sensing field. All academics, bench scientists, and industry professionals wishing to take advantage of the latest and greatest in the continuously emerging field of glucose sensing, and diabetes care & management, will find this volume an invaluable resource. Topics in Fluorescence Spectroscopy Volume 11, Glucose Sensing Chapters include: Implantable Sensors for Interstitial Fluid Smart Tattoo Glucose Sensors Optical Enzyme-based Glucose Biosensors Plasmonic Glucose Sens...

  6. Glucose effects on long-term memory performance: duration and domain specificity.

    Science.gov (United States)

    Owen, Lauren; Finnegan, Yvonne; Hu, Henglong; Scholey, Andrew B; Sünram-Lea, Sandra I

    2010-08-01

    Previous research has suggested that long-term verbal declarative memory is particularly sensitive to enhancement by glucose loading; however, investigation of glucose effects on certain memory domains has hitherto been neglected. Therefore, domain specificity of glucose effects merits further elucidation. The aim of the present research was to provide a more comprehensive investigation of the possible effects of glucose administration on different aspects of memory by 1) contrasting the effect of glucose administration on different memory domains (implicit/explicit memory; verbal/non-verbal memory, and recognition/familiarity processes), 2) investigating whether potential effects on memory domains differ depending on the dose of glucose administered (25 g versus 60 g), 3) exploring the duration of the glucose facilitation effect (assessment of memory performance 35 min and 1 week after encoding). A double-blind between-subjects design was used to test the effects of administration of 25 and 60 g glucose on memory performance. Implicit memory was improved following administration of 60 g of glucose. Glucose supplementation failed to improve face recognition performance but significantly improved performance of word recall and recognition following administration of 60 g of glucose. However, effects were not maintained 1 week following encoding. Improved implicit memory performance following glucose administration has not been reported before. Furthermore, the current data tentatively suggest that level of processing may determine the required glucose dosage to demonstrate memory improvement and that higher dosages may be able to exert effects on memory pertaining to both hippocampal and non-hippocampal brain regions.

  7. The influence of GLP-1 on glucose-stimulated insulin secretion: effects on beta-cell sensitivity in type 2 and nondiabetic subjects

    DEFF Research Database (Denmark)

    Kjems, Lise L; Holst, Jens J; Vølund, Aage

    2003-01-01

    . However, the dose-response relationship between GLP-1 and basal and glucose-stimulated prehepatic insulin secretion rate (ISR) is currently not known. Seven patients with type 2 diabetes and seven matched nondiabetic control subjects were studied. ISR was determined during a graded glucose infusion of 2...

  8. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... EXPO Volunteer Opportunities Sponsorship and Exhibit Opportunities Camp ... when ketones are present may make your blood glucose level go even higher. You'll need to work with your doctor ...

  9. CSF glucose test

    Science.gov (United States)

    ... in the space surrounding the spinal cord and brain. ... Abnormal results include higher and lower glucose levels. Abnormal results may be due to: Infection (bacterial or fungus) Inflammation of the central nervous system Tumor

  10. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... blood glucose level go even higher. You'll need to work with your doctor to find the ... lead to ketoacidosis. Ketoacidosis is life-threatening and needs immediate treatment. Symptoms include: Shortness of breath Breath ...

  11. β-Adrenoceptor activation depresses brain inflammation and is neuroprotective in lipopolysaccharide-induced sensitization to oxygen-glucose deprivation in organotypic hippocampal slices

    Directory of Open Access Journals (Sweden)

    Cilio Corrado

    2010-12-01

    Full Text Available Abstract Background Inflammation acting in synergy with brain ischemia aggravates perinatal ischemic brain damage. The sensitizing effect of pro-inflammatory exposure prior to hypoxia is dependent on signaling by TNF-α through TNF receptor (TNFR 1. Adrenoceptor (AR activation is known to modulate the immune response and synaptic transmission. The possible protective effect of α˜ and β˜AR activation against neuronal damage caused by tissue ischemia and inflammation, acting in concert, was evaluated in murine hippocampal organotypic slices treated with lipopolysaccharide (LPS and subsequently subjected to oxygen-glucose deprivation (OGD. Method Hippocampal slices from mice were obtained at P6, and were grown in vitro for 9 days on nitrocellulose membranes. Slices were treated with β1(dobutamine-, β2(terbutaline-, α1(phenylephrine- and α2(clonidine-AR agonists (5 and 50 μM, respectively during LPS (1 μg/mL, 24 h -exposure followed by exposure to OGD (15 min in a hypoxic chamber. Cell death in the slice CA1 region was assessed by propidium iodide staining of dead cells. Results Exposure to LPS + OGD caused extensive cell death from 4 up to 48 h after reoxygenation. Co-incubation with β1-agonist (50 μM during LPS exposure before OGD conferred complete protection from cell death (P -/- and TNFR2-/- slices exposed to LPS followed by OGD. Conclusions Our data demonstrate that activation of both β1- and β2-receptors is neuroprotective and may offer mechanistic insights valuable for development of neuro-protective strategies in neonates.

  12. O-Fucose Monosaccharide of Drosophila Notch Has a Temperature-sensitive Function and Cooperates with O-Glucose Glycan in Notch Transport and Notch Signaling Activation*

    Science.gov (United States)

    Ishio, Akira; Sasamura, Takeshi; Ayukawa, Tomonori; Kuroda, Junpei; Ishikawa, Hiroyuki O.; Aoyama, Naoki; Matsumoto, Kenjiroo; Gushiken, Takuma; Okajima, Tetsuya; Yamakawa, Tomoko; Matsuno, Kenji

    2015-01-01

    Notch (N) is a transmembrane receptor that mediates the cell-cell interactions necessary for many cell fate decisions. N has many epidermal growth factor-like repeats that are O-fucosylated by the protein O-fucosyltransferase 1 (O-Fut1), and the O-fut1 gene is essential for N signaling. However, the role of the monosaccharide O-fucose on N is unclear, because O-Fut1 also appears to have O-fucosyltransferase activity-independent functions, including as an N-specific chaperon. Such an enzymatic activity-independent function could account for the essential role of O-fut1 in N signaling. To evaluate the role of the monosaccharide O-fucose modification in N signaling, here we generated a knock-in mutant of O-fut1 (O-fut1R245A knock-in), which expresses a mutant protein that lacks O-fucosyltransferase activity but maintains the N-specific chaperon activity. Using O-fut1R245A knock-in and other gene mutations that abolish the O-fucosylation of N, we found that the monosaccharide O-fucose modification of N has a temperature-sensitive function that is essential for N signaling. The O-fucose monosaccharide and O-glucose glycan modification, catalyzed by Rumi, function redundantly in the activation of N signaling. We also showed that the redundant function of these two modifications is responsible for the presence of N at the cell surface. Our findings elucidate how different forms of glycosylation on a protein can influence the protein's functions. PMID:25378397

  13. Insulin secretion and incretin hormones after oral glucose in non-obese subjects with impaired glucose tolerance

    DEFF Research Database (Denmark)

    Rask, E; Olsson, T; Söderberg, S

    2004-01-01

    of glucose, insulin, C-peptide, GLP-1, and GIP. Insulin secretion (TIS) and insulin sensitivity (OGIS) were assessed using models describing the relationship between glucose, insulin and C-peptide data. These models allowed estimation also of the hepatic extraction of insulin. The age (54.2 +/- 9.7 [mean......Subjects with impaired glucose tolerance (IGT) are usually overweight and exhibit insulin resistance with a defective compensation of insulin secretion. In this study, we sought to establish the interrelation between insulin secretion and insulin sensitivity after oral glucose in non-obese subjects...... over the whole 180-minute period was higher in IGT (26.2 +/- 2.4 v 20.0 +/- 2.0 nmol/L; P =.035). Hepatic insulin extraction correlated linearly with OGIS (r = 0.71; P

  14. Biosynthesis of higher alcohol flavour compounds by the yeast Saccharomyces cerevisiae: impact of oxygen availability and responses to glucose pulse in minimal growth medium with leucine as sole nitrogen source.

    Science.gov (United States)

    Espinosa Vidal, Esteban; de Morais, Marcos Antonio; François, Jean Marie; de Billerbeck, Gustavo M

    2015-01-01

    Higher alcohol formation by yeast is of great interest in the field of fermented beverages. Among them, medium-chain alcohols impact greatly the final flavour profile of alcoholic beverages, even at low concentrations. It is widely accepted that amino acid metabolism in yeasts directly influences higher alcohol formation, especially the catabolism of aromatic and branched-chain amino acids. However, it is not clear how the availability of oxygen and glucose metabolism influence the final higher alcohol levels in fermented beverages. Here, using an industrial Brazilian cachaça strain of Saccharomyces cerevisiae, we investigated the effect of oxygen limitation and glucose pulse on the accumulation of higher alcohol compounds in batch cultures, with glucose (20 g/l) and leucine (9.8 g/l) as the carbon and nitrogen sources, respectively. Fermentative metabolites and CO2 /O2 balance were analysed in order to correlate the results with physiological data. Our results show that the accumulation of isoamyl alcohol by yeast is independent of oxygen availability in the medium, depending mainly on leucine, α-keto-acids and/or NADH pools. High-availability leucine experiments showed a novel and unexpected accumulation of isobutanol, active amyl alcohol and 2-phenylethanol, which could be attributed to de novo biosynthesis of valine, isoleucine and phenylalanine and subsequent outflow of these pathways. In carbon-exhausted conditions, our results also describe, for the first time, the metabolization of isoamyl alcohol, isobutanol, active amyl alcohol but not of 2-phenylethanol, by yeast strains in stationary phase, suggesting a role for these higher alcohols as carbon source for cell maintenance and/or redox homeostasis during this physiological phase. Copyright © 2014 John Wiley & Sons, Ltd.

  15. Using mineralogy and higher-level taxonomy as indicators of species sensitivity to pH: A case-study of Puget Sound

    Directory of Open Access Journals (Sweden)

    Shallin Busch

    2017-09-01

    Full Text Available Information on ecosystem sensitivity to global change can help guide management decisions. Here, we characterize the sensitivity of the Puget Sound ecosystem to ocean acidification by estimating, at a number of taxonomic levels, the direct sensitivity of its species. We compare sensitivity estimates based on species mineralogy and on published literature from laboratory experiments and field studies. We generated information on the former by building a database of species in Puget Sound with mineralogy estimates for all CaCO3-forming species. For the latter, we relied on a recently developed database and meta-analysis on temperate species responses to increased CO2. In general, species sensitivity estimates based on the published literature suggest that calcifying species are more sensitive to increased CO2 than non-calcifying species. However, this generalization is incomplete, as non-calcifying species also show direct sensitivity to high CO2 conditions. We did not find a strong link between mineral solubility and the sensitivity of species survival to changes in carbonate chemistry, suggesting that, at coarse scales, mineralogy plays a lesser role to other physiological sensitivities. Summarizing species sensitivity at the family level resulted in higher sensitivity scalar scores than at the class level, suggesting that grouping results at the class level may overestimate species sensitivity. This result raises caution about the use of broad generalizations on species response to ocean acidification, particularly when developing summary information for specific locations. While we have much to learn about species response to ocean acidification and how to generalize ecosystem response, this study on Puget Sound suggests that detailed information on species performance under elevated carbon dioxide conditions, summarized at the lowest taxonomic level possible, is more valuable than information on species mineralogy.

  16. Weight loss after bariatric surgery reverses insulin-induced increases in brain glucose metabolism of the morbidly obese.

    Science.gov (United States)

    Tuulari, Jetro J; Karlsson, Henry K; Hirvonen, Jussi; Hannukainen, Jarna C; Bucci, Marco; Helmiö, Mika; Ovaska, Jari; Soinio, Minna; Salminen, Paulina; Savisto, Nina; Nummenmaa, Lauri; Nuutila, Pirjo

    2013-08-01

    Obesity and insulin resistance are associated with altered brain glucose metabolism. Here, we studied brain glucose metabolism in 22 morbidly obese patients before and 6 months after bariatric surgery. Seven healthy subjects served as control subjects. Brain glucose metabolism was measured twice per imaging session: with and without insulin stimulation (hyperinsulinemic-euglycemic clamp) using [18F]fluorodeoxyglucose scanning. We found that during fasting, brain glucose metabolism was not different between groups. However, the hyperinsulinemic clamp increased brain glucose metabolism in a widespread manner in the obese but not control subjects, and brain glucose metabolism was significantly higher during clamp in obese than in control subjects. After follow-up, 6 months postoperatively, the increase in glucose metabolism was no longer observed, and this attenuation was coupled with improved peripheral insulin sensitivity after weight loss. We conclude that obesity is associated with increased insulin-stimulated glucose metabolism in the brain and that this abnormality can be reversed by bariatric surgery.

  17. Thermogenic Effect of Glucose in Hypothyroid Subjects

    Directory of Open Access Journals (Sweden)

    Agnieszka Kozacz

    2014-01-01

    Full Text Available The importance of thyroid hormone, catecholamines, and insulin in modification of the thermogenic effect of glucose (TEG was examined in 34 healthy and 32 hypothyroid subjects. We calculated the energy expenditure at rest and during oral glucose tolerance test. Blood samples for determinations of glucose, plasma insulin, adrenaline (A, and noradrenaline (NA were collected. It was found that TEG was lower in hypothyroid than in control group (19.68±3.90 versus 55.40±7.32 kJ, resp., P<0.0004. Mean values of glucose and insulin areas under the curve were higher in women with hypothyroidism than in control group (286.79±23.65 versus 188.41±15.84 mmol/L·min, P<0.003 and 7563.27±863.65 versus 4987.72±583.88 mU/L·min, P<0.03 resp.. Maximal levels of catecholamines after glucose ingestion were higher in hypothyroid patients than in control subjects (Amax—0.69±0.08 versus 0.30±0.07 nmol/L, P<0.0001, and NAmax—6.42±0.86 versus 2.54±0.30 nmol/L, P<0.0002. It can be concluded that in hypothyroidism TEG and glucose tolerance are decreased while the adrenergic response to glucose administration is enhanced. Presumably, these changes are related to decreased insulin sensitivity and responsiveness to catecholamine action.

  18. Relationships of plasma adiponectin level and adiponectin receptors 1 and 2 gene expression to insulin sensitivity and glucose and fat metabolism in monozygotic and dizygotic twins

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Poulsen, Pernille; Ling, Charlotte

    2007-01-01

    and muscle AdipoR1/R2 gene expression and the impact of these components on in vivo glucose and fat metabolism. DESIGN AND PARTICIPANTS: Plasma adiponectin and muscle gene expression of AdipoR1/R2 were measured before and during insulin infusion in 89 young and 69 elderly monozygotic and dizygotic twins...... influenced by age, sex, abdominal obesity, and aerobic capacity. Intrapair correlations in monozygotic twins indicated a nongenetic influence of birth weight on plasma adiponectin and AdipoR2 expression. Nonoxidative glucose metabolism was associated with AdipoR1 and plasma adiponectin, in young and elderly...

  19. Low-volume high-intensity swim training is superior to high-volume low-intensity training in relation to insulin sensitivity and glucose control in inactive middle-aged women.

    Science.gov (United States)

    Connolly, Luke J; Nordsborg, Nikolai B; Nyberg, Michael; Weihe, Pál; Krustrup, Peter; Mohr, Magni

    2016-10-01

    We tested the hypothesis that low-volume high-intensity swimming has a larger impact on insulin sensitivity and glucose control than high-volume low-intensity swimming in inactive premenopausal women with mild hypertension. Sixty-two untrained premenopausal women were randomised to an inactive control (n = 20; CON), a high-intensity low-volume (n = 21; HIT) or a low-intensity high-volume (n = 21; LIT) training group. During the 15-week intervention period, HIT performed 3 weekly 6-10 × 30-s all-out swimming intervals (average heart rate (HR) = 86 ± 3 % HRmax) interspersed by 2-min recovery periods and LIT swam continuously for 1 h at low intensity (average HR = 73 ± 3 % HRmax). Fasting blood samples were taken and an oral glucose tolerance test (OGTT) was conducted pre- and post-intervention. After HIT, resting plasma [insulin] was lowered (17 ± 34 %; P high-intensity intermittent swimming is an effective and time-efficient training strategy for improving insulin sensitivity, glucose control and biomarkers of vascular function in inactive, middle-aged mildly hypertensive women.

  20. Higher admission fasting plasma glucose levels are associated with a poorer short-term neurologic outcome in acute ischemic stroke patients with good collateral circulation.

    Science.gov (United States)

    Wang, Feng; Jiang, Beisi; Kanesan, Lasheta; Zhao, Yuwu; Yan, Bernard

    2018-04-12

    In this retrospective study, we sought to delineate the collateral circulation status of acute ischemic stroke patients by CT perfusion and evaluate 90-day modified Rankin Scale (mRS) scores of patients with good or poor collaterals and its correlation with admission fasting plasma glucose (FPG). We enrolled acute ischemic stroke patients who presented to our hospital 4.5 h within an onset of the first episode between January 2009 and December 2015. Neurological assessment was performed using the 90-day mRS scores (0-2 for a favorable and 3-6 for an unfavorable neurologic outcome). Relative filling time delay (rFTD) was evaluated by CT perfusion scan. The primary outcomes were 90-day mRS scores stratified by good (rFTD ≤ 4 s) versus poor collateral circulation (rFTD > 4 s). Totally 270 patients were included, and 139 (51.5%) patients achieved a favorable neurologic outcome. One hundred eighty-five (68.5%) patients had good collateral circulation. Significantly greater portions of patients with good collateral circulation (60.5%, 112/185) achieved a favorable neurologic outcome compared to those with poor collateral circulation (31.8%, 27/85) (P collateral circulation achieving a favorable neurologic outcome had significantly lower baseline FPG (6.6 ± 1.96) than those with good collateral circulation achieving an unfavorable neurologic outcome (8.12 ± 4.02; P = 0.002). Spearman correlation analysis showed that rFTD significantly correlated with 90-day mRS scores (adjusted r = 0.258; P collateral circulation. FPG and rFTD may serve as useful predictors of short-term patient outcome and could be used for risk stratification in clinical decision making.

  1. Glucose enhancement of memory is modulated by trait anxiety in healthy adolescent males.

    Science.gov (United States)

    Smith, Michael A; Hii, Hilary L; Foster, Jonathan K; van Eekelen, J A M

    2011-01-01

    Glucose administration is associated with memory enhancement in healthy young individuals under conditions of divided attention at encoding. While the specific neurocognitive mechanisms underlying this 'glucose memory facilitation effect' are currently uncertain, it is thought that individual differences in glucoregulatory efficiency may alter an individual's sensitivity to the glucose memory facilitation effect. In the present study, we sought to investigate whether basal hypothalamic-pituitary-adrenal axis function (itself a modulator of glucoregulatory efficiency), baseline self-reported stress and trait anxiety influence the glucose memory facilitation effect. Adolescent males (age range = 14-17 years) were administered glucose and placebo prior to completing a verbal episodic memory task on two separate testing days in a counter-balanced, within-subjects design. Glucose ingestion improved verbal episodic memory performance when memory recall was tested (i) within an hour of glucose ingestion and encoding, and (ii) one week subsequent to glucose ingestion and encoding. Basal hypothalamic-pituitary-adrenal axis function did not appear to influence the glucose memory facilitation effect; however, glucose ingestion only improved memory in participants reporting relatively higher trait anxiety. These findings suggest that the glucose memory facilitation effect may be mediated by biological mechanisms associated with trait anxiety.

  2. Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe.

    Science.gov (United States)

    Khansaritoreh, Elmira; Dulamsuren, Choimaa; Klinge, Michael; Ariunbaatar, Tumurbaatar; Bat-Enerel, Banzragch; Batsaikhan, Ganbaatar; Ganbaatar, Kherlenchimeg; Saindovdon, Davaadorj; Yeruult, Yolk; Tsogtbaatar, Jamsran; Tuya, Daramragchaa; Leuschner, Christoph; Hauck, Markus

    2017-09-01

    Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland-dominated forest-steppe area and small forest patches in a grassland-dominated area. We found increasing climate sensitivity and decreasing first-order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland-dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland-dominated area, the increase was much greater than in the forest-dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure. © 2017 John Wiley & Sons Ltd.

  3. Glucose allostasis

    DEFF Research Database (Denmark)

    Stumvoll, Michael; Tataranni, P Antonio; Stefan, Norbert

    2003-01-01

    individuals with normal glucose tolerance, normoglycemia can always be maintained by compensatorily increasing AIR in response to decreasing M (and vice versa). This has been mathematically described by the hyperbolic relationship between AIR and M and referred to as glucose homeostasis, with glucose......In many organisms, normoglycemia is achieved by a tight coupling of nutrient-stimulated insulin secretion in the pancreatic beta-cell (acute insulin response [AIR]) and the metabolic action of insulin to stimulate glucose disposal (insulin action [M]). It is widely accepted that in healthy...... concentration assumed to remain constant along the hyperbola. Conceivably, glucose is one of the signals stimulating AIR in response to decreasing M. Hypothetically, as with any normally functioning feed-forward system, AIR should not fully compensate for worsening M, since this would remove the stimulus...

  4. Women With Gestational Diabetes Mellitus Randomized to a Higher-Complex Carbohydrate/Low-Fat Diet Manifest Lower Adipose Tissue Insulin Resistance, Inflammation, Glucose, and Free Fatty Acids: A Pilot Study.

    Science.gov (United States)

    Hernandez, Teri L; Van Pelt, Rachael E; Anderson, Molly A; Reece, Melanie S; Reynolds, Regina M; de la Houssaye, Becky A; Heerwagen, Margaret; Donahoo, William T; Daniels, Linda J; Chartier-Logan, Catherine; Janssen, Rachel C; Friedman, Jacob E; Barbour, Linda A

    2016-01-01

    Diet therapy in gestational diabetes mellitus (GDM) has focused on carbohydrate restriction but is poorly substantiated. In this pilot randomized clinical trial, we challenged the conventional low-carbohydrate/higher-fat (LC/CONV) diet, hypothesizing that a higher-complex carbohydrate/lower-fat (CHOICE) diet would improve maternal insulin resistance (IR), adipose tissue (AT) lipolysis, and infant adiposity. At 31 weeks, 12 diet-controlled overweight/obese women with GDM were randomized to an isocaloric LC/CONV (40% carbohydrate/45% fat/15% protein; n = 6) or CHOICE (60%/25%/15%; n = 6) diet. All meals were provided. AT was biopsied at 37 weeks. After ∼7 weeks, fasting glucose (P = 0.03) and free fatty acids (P = 0.06) decreased on CHOICE, whereas fasting glucose increased on LC/CONV (P = 0.03). Insulin suppression of AT lipolysis was improved on CHOICE versus LC/CONV (56 vs. 31%, P = 0.005), consistent with improved IR. AT expression of multiple proinflammatory genes was lower on CHOICE (P vs. 12.6 ± 2%, respectively). A CHOICE diet may improve maternal IR and infant adiposity, challenging recommendations for a LC/CONV diet. © 2016 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.

  5. Longer habitual afternoon napping is associated with a higher risk for impaired fasting plasma glucose and diabetes mellitus in older adults: results from the Dongfeng-Tongji cohort of retired workers.

    Science.gov (United States)

    Fang, Weimin; Li, Zhongliang; Wu, Li; Cao, Zhongqiang; Liang, Yuan; Yang, Handong; Wang, Youjie; Wu, Tangchun

    2013-10-01

    Afternoon napping is a common habit in China. We used data obtained from the Dongfeng-Tongji cohort to examine if duration of habitual afternoon napping was associated with risks for impaired fasting plasma glucose (IFG) and diabetes mellitus (DM) in a Chinese elderly population. A total of 27,009 participants underwent a physical examination, laboratory tests, and face-to-face interview. They were categorized into four groups according to nap duration (no napping, or =90 min). Logistic regression models were used to examine the odds ratios (ORs) of napping duration with IFG and DM. Of the participants, 18,515 (68.6%) reported regularly taking afternoon naps. Those with longer nap duration had considerably higher prevalence of IFG and DM. Napping duration was associated in a dose-dependent manner with IFG and DM (Pnap duration (>60 min; all Pnap duration (>30 min) was associated with increased risk for DM; however, this finding was not significant in the group with a nap duration of 60-90 min. Longer habitual afternoon napping was associated with a moderate increase for DM risk, independent of several covariates. This finding suggests that longer nap duration may represent a novel risk factor for DM and higher blood glucose levels. Copyright © 2013. Published by Elsevier B.V.

  6. Hypothalamic and Striatal Insulin Action Suppresses Endogenous Glucose Production and May Stimulate Glucose Uptake During Hyperinsulinemia in Lean but Not in Overweight Men.

    Science.gov (United States)

    Heni, Martin; Wagner, Robert; Kullmann, Stephanie; Gancheva, Sofiya; Roden, Michael; Peter, Andreas; Stefan, Norbert; Preissl, Hubert; Häring, Hans-Ulrich; Fritsche, Andreas

    2017-07-01

    Intranasal spray application facilitates insulin delivery to the human brain. Although brain insulin modulates peripheral metabolism, the mechanisms involved remain elusive. Twenty-one men underwent two hyperinsulinemic-euglycemic clamps with d-[6,6- 2 H 2 ]glucose infusion to measure endogenous glucose production and glucose disappearance. On two separate days, participants received intranasal insulin or placebo. Insulin spillover into circulation after intranasal insulin application was mimicked by an intravenous insulin bolus on placebo day. On a different day, brain insulin sensitivity was assessed by functional MRI. Glucose infusion rates (GIRs) had to be increased more after nasal insulin than after placebo to maintain euglycemia in lean but not in overweight people. The increase in GIRs was associated with regional brain insulin action in hypothalamus and striatum. Suppression of endogenous glucose production by circulating insulin was more pronounced after administration of nasal insulin than after placebo. Furthermore, glucose uptake into tissue tended to be higher after nasal insulin application. No such effects were detected in overweight participants. By increasing insulin-mediated suppression of endogenous glucose production and stimulating peripheral glucose uptake, brain insulin may improve glucose metabolism during systemic hyperinsulinemia. Obese people appear to lack these mechanisms. Therefore, brain insulin resistance in obesity may have unfavorable consequences for whole-body glucose homeostasis. © 2017 by the American Diabetes Association.

  7. Association of Androgen Excess with Glucose Intolerance in Women with Polycystic Ovary Syndrome.

    Science.gov (United States)

    Zhang, Bingjie; Wang, Jing; Shen, Shanmei; Liu, Jiayi; Sun, Jie; Gu, Tianwei; Ye, Xiao; Zhu, Dalong; Bi, Yan

    2018-01-01

    Women with polycystic ovary syndrome (PCOS) show high prevalence of glucose intolerance. This study aimed to investigate the association of androgen excess with glucose intolerance in PCOS. A total of 378 women with PCOS participated in the study. Free androgen index (FAI) was selected as indicator of hyperandrogenism. Insulin sensitivity was assessed by 1/homeostasis model assessment of insulin resistance (1/HOMA-IR) and Matsuda insulin sensitivity index (ISI M ); β -cell function was assessed by disposition index (DI). We found that women with glucose intolerance had higher FAI levels compared to women with normal glucose tolerance (NGT) (prediabetes 6.2, T2DM 7.9 versus NGT 5.0, resp.; p androgen excess indicated by high FAI levels might serve as indicator of glucose intolerance, as it might promote insulin resistance and β -cell dysfunction in women with PCOS.

  8. Effect of metformin on substrate utilization after exercise training in adults with impaired glucose tolerance.

    Science.gov (United States)

    Malin, Steven K; Braun, Barry

    2013-04-01

    Metformin attenuates the higher insulin sensitivity that occurs with exercise training. Sixteen people with prediabetes trained for 10 weeks while taking metformin (n = 8) or placebo (n = 8). Substrate utilization was assessed using glucose kinetics and indirect calorimetry. After training, exercise whole-body fat oxidation was higher and glycogen use lower (p use was unchanged. Training-induced enhancement of insulin sensitivity (clamp) correlated with higher peak oxygen uptake (r = 0.70; p < 0.05), but was independent of glucose kinetic and substrate metabolism.

  9. Cellular and molecular cues of glucose sensing in the rat olfactory bulb

    Directory of Open Access Journals (Sweden)

    Dolly eAl Koborssy

    2014-10-01

    Full Text Available In the brain, glucose homeostasis of extracellular fluid is crucial to the point that systems specifically dedicated to glucose sensing are found in areas involved in energy regulation and feeding behavior. Olfaction is a major sensory modality regulating food consumption. Nutritional status in turn modulates olfactory detection. Recently it has been proposed that some olfactory bulb (OB neurons respond to glucose similarly to hypothalamic neurons. However, the precise molecular cues governing glucose sensing in the OB are largely unknown. To decrypt these molecular mechanisms, we first used immunostaining to demonstrate a strong expression of two neuronal markers of glucose-sensitivity, insulin-dependent glucose transporter type 4 (GLUT4, and sodium glucose co-transporter type 1 (SGLT1 in specific OB layers. We showed that expression and mapping of GLUT4 but not SGLT1 were feeding state-dependent. In order to investigate the impact of metabolic status on the delivery of blood-borne glucose to the OB, we measured extracellular fluid glucose concentration using glucose biosensors simultaneously in the OB and cortex of anesthetized rats. We showed that glucose concentration in the OB is higher than in the cortex, that metabolic steady-state glucose concentration is independent of feeding state in the two brain areas, and that acute changes in glycemic conditions affect bulbar glucose concentration alone. These data provide new evidence of a direct relationship between the OB and peripheral metabolism, and emphasize the importance of glucose for the OB network, providing strong arguments toward establishing the OB as a glucose-sensing organ.

  10. Analysis on the effect of polysulfide electrolyte composition for higher performance of Si quantum dot-sensitized solar cells

    International Nuclear Information System (INIS)

    Seo, Hyunwoong; Wang, Yuting; Uchida, Giichiro; Kamataki, Kunihiro; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

    2013-01-01

    Quantum dot-sensitized solar cell (QDSC) based on multiple exciton generation of QD has been expected to realize high efficiency. This work focused on Si QD instead of conventional QD materials because of their toxicity and scarcity. Si QDs were fabricated by multi-hollow discharge plasma chemical vapor deposition. General QDSCs use polysulfide electrolyte because it is suitable for stabilizing QDs and its redox reaction is the best as compared with other redox systems. The improvement of redox reaction which is one of the slowest reactions in the kinetic analysis is closely connected with the enhancement of performance. For the enhancement on the overall performance of Si QDSC, the performance dependence on electrolyte composition was investigated. The concentrations of Na 2 S and S were varied for the activation of redox reaction and KCl concentration was optimized for the improvement of electrolyte characteristics. Consequently, the best performance of Si QDSC was obtained with 1 M Na 2 S, 2 M S, and 0.4 M KCl polysulfide electrolyte

  11. Higher Levels of c-Met Expression and Phosphorylation Identify Cell Lines With Increased Sensitivity to AMG-458, a Novel Selective c-Met Inhibitor With Radiosensitizing Effects

    International Nuclear Information System (INIS)

    Li Bo; Torossian, Artour; Sun, Yunguang; Du, Ruihong; Dicker, Adam P.; Lu Bo

    2012-01-01

    Purpose: c-Met is overexpressed in some non-small cell lung cancer (NSCLC) cell lines and tissues. Cell lines with higher levels of c-Met expression and phosphorylation depend on this receptor for survival. We studied the effects of AMG-458 on 2 NSCLC cell lines. Methods and Materials: 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H-tetrazolium assays assessed the sensitivities of the cells to AMG-458. Clonogenic survival assays illustrated the radiosensitizing effects of AMG-458. Western blot for cleaved caspase 3 measured apoptosis. Immunoblotting for c-Met, phospho-Met (p-Met), Akt/p-Akt, and Erk/p-Erk was performed to observe downstream signaling. Results: AMG-458 enhanced radiosensitivity in H441 but not in A549. H441 showed constitutive phosphorylation of c-Met. A549 expressed low levels of c-Met, which were phosphorylated only in the presence of exogenous hepatocyte growth factor. The combination of radiation therapy and AMG-458 treatment was found to synergistically increase apoptosis in the H441 cell line but not in A549. Radiation therapy, AMG-458, and combination treatment were found to reduce p-Akt and p-Erk levels in H441 but not in A549. H441 became less sensitive to AMG-458 after small interfering RNA knockdown of c-Met; there was no change in A549. After overexpression of c-Met, A549 became more sensitive, while H441 became less sensitive to AMG-458. Conclusions: AMG-458 was more effective in cells that expressed higher levels of c-Met/p-Met, suggesting that higher levels of c-Met and p-Met in NSCLC tissue may classify a subset of tumors that are more sensitive to molecular therapies against this receptor.

  12. Glucose sensing based on Pt-MWCNT and MWCNT

    Science.gov (United States)

    Aryasomayajula, Lavanya; Xie, Jining; Wang, Shouyan; Varadan, Vijay K.

    2007-04-01

    It is known that multi walled carbon nanotubes (MWCNTs) is an excellent materials for biosensing applications and with the introduction of Pt nanoparticles (Pt-MWCNTs) of about 3nm in diameter in MWCNTs greatly increases the current sensitivity and also the signal to noise ratio. We fabricated the CNT- based glucose sensor by immobilization the bio enzyme, glucose oxidase (GoX), on the Pt-MWCNT and electrode were prepared. The sensor has been tested effectively for both the abnormal blood glucose levels- greater than 6.9 mM and less than 3.5 mM which are the prediabetic and diabetic glucose levels, respectively. The current signal obtained from the Pt-MWCNT was much higher compared to the MWCNT based sensors.

  13. Fluorescent sensors based on quinoline-containing styrylcyanine: determination of ferric ions, hydrogen peroxide, and glucose, pH-sensitive properties and bioimaging.

    Science.gov (United States)

    Yang, Xiaodong; Zhao, Peiliang; Qu, Jinqing; Liu, Ruiyuan

    2015-08-01

    A novel styrylcyanine-based fluorescent probe 1 was designed and synthesized via facile methods. Ferric ions quenched the fluorescence of probe 1, whereas the addition of ferrous ions led to only small changes in the fluorescence signal. When hydrogen peroxide was introduced into the solution containing probe 1 and Fe(2+) , Fe(2+) was oxidized to Fe(3+), resulting in the quenching of the fluorescence. The probe 1/Fe(2+) solution fluorescence could also be quenched by H2 O2 released from glucose oxidation by glucose oxidase (GOD), which means that probe 1/Fe(2+) platform could be used to detect glucose. Probe 1 is fluorescent in basic and neutral media but almost non-fluorescent in strong acidic environments. Such behaviour enables it to work as a fluorescent pH sensor in both the solution and solid states and as a chemosensor for detecting volatile organic compounds with high acidity and basicity. Subsequently, the fluorescence microscopic images of probe 1 in live cells and in zebrafish were achieved successfully, suggesting that the probe has good cell membrane permeability and a potential application for imaging in living cells and living organisms. Copyright © 2014 John Wiley & Sons, Ltd.

  14. Glucose effectiveness, but not insulin sensitivity, is improved after short-term interval training in individuals with type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Karstoft, Kristian; Clark, Margaret A; Jakobsen, Ida

    2017-01-01

    in S G, but not in S I, were associated with changes in mean (β = -0.62 ± 0.23, r 2 = 0.17, p 1.18 ± 0.52, r 2 = 0.12, p levels during 24 h continuous glucose monitoring. CONCLUSIONS/INTERPRETATION: Two weeks of IWT, but not CWT, improves S G but not S I......AIMS/HYPOTHESIS: The role of glucose effectiveness (S G) in training-induced improvements in glucose metabolism in individuals with type 2 diabetes is unknown. The objectives and primary outcomes of this study were: (1) to assess the efficacy of interval walking training (IWT) and continuous...... interventions. RESULTS: Thirteen individuals completed all procedures and were included in the analyses. IWT improved S G (mean ± SEM: 0.6 ± 0.1 mg kg-1 min-1, p 0.05), whereas CWT matched for energy expenditure and time duration improved neither S G nor S I (both p > 0.05). Changes...

  15. Intermittent Hypoxia Impairs Glucose Homeostasis in C57BL6/J Mice: Partial Improvement with Cessation of the Exposure

    Science.gov (United States)

    Polak, Jan; Shimoda, Larissa A.; Drager, Luciano F.; Undem, Clark; McHugh, Holly; Polotsky, Vsevolod Y.; Punjabi, Naresh M.

    2013-01-01

    Objectives: Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued. Interventions: C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed. Results: Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted. Conclusions: Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism. Citation: Polak J; Shimoda LA; Drager LF; Undem C; McHugh H; Polotsky VY; Punjabi NM

  16. Porous HKUST-1 derived CuO/Cu2O shell wrapped Cu(OH)2 derived CuO/Cu2O core nanowire arrays for electrochemical nonenzymatic glucose sensors with ultrahigh sensitivity

    Science.gov (United States)

    Yu, Cuiping; Cui, Jiewu; Wang, Yan; Zheng, Hongmei; Zhang, Jianfang; Shu, Xia; Liu, Jiaqin; Zhang, Yong; Wu, Yucheng

    2018-05-01

    Self-supported CuO/Cu2O@CuO/Cu2O core-shell nanowire arrays (NWAs) are successfully fabricated by a simple and efficient method in this paper. Anodized Cu(OH)2 NWAs could in-situ convert to HKUST-1 at room temperature easily. Cu(OH)2 NWAs cores and HKUST-1 shells transform into CuO/Cu2O simultaneously after calcinations and form CuO/Cu2O@CuO/Cu2O core-shell NWAs. This smart configuration of the core-shell structure not only avoids the agglomeration of the traditional MOF-derived materials in particle-shape, but also facilitates the ion diffusion and increases the active sites. This novel structure is employed as substrate to construct nonenzymatic glucose sensors. The results indicate that glucose sensor based on CuO/Cu2O@CuO/Cu2O core-shell NWAs presents ultrahigh sensitivity (10,090 μA mM-1 cm-2), low detection limit (0.48 μM) and wide linear range (0.99-1,330 μM). In addition, it also shows excellent anti-interference ability toward uric acid, ascorbic acid and L-Cysteine co-existing with glucose, good reproducibility and superior ability of real sample analysis.

  17. A Lower-Carbohydrate, Higher-Fat Diet Reduces Abdominal and Intermuscular Fat and Increases Insulin Sensitivity in Adults at Risk of Type 2 Diabetes123

    Science.gov (United States)

    Gower, Barbara A; Goss, Amy M

    2015-01-01

    Background: Obesity, particularly visceral and ectopic adiposity, increases the risk of type 2 diabetes. Objective: The aim of this study was to determine if restriction of dietary carbohydrate is beneficial for body composition and metabolic health. Methods: Two studies were conducted. In the first, 69 overweight/obese men and women, 53% of whom were European American (EA) and 47% of whom were African American (AA), were provided with 1 of 2 diets (lower-fat diet: 55%, 18%, and 27% of energy from carbohydrate, protein, and fat, respectively; lower-carbohydrate diet: 43%, 18%, and 39%, respectively) for 8 wk at a eucaloric level and 8 wk at a hypocaloric level. In the second study, 30 women with polycystic ovary syndrome (PCOS) were provided with 2 diets (lower-fat diet: 55%, 18%, and 27% of energy from carbohydrate, protein, and fat, respectively; lower-carbohydrate diet: 41%, 19%, and 40%, respectively) at a eucaloric level for 8 wk in a random-order crossover design. Results: As previously reported, among overweight/obese adults, after the eucaloric phase, participants who consumed the lower-carbohydrate vs. the lower-fat diet lost more intra-abdominal adipose tissue (IAAT) (11 ± 3% vs. 1 ± 3%; P diet had 4.4% less total fat mass. Original to this report, across the entire 16-wk study, AAs lost more fat mass with a lower-carbohydrate diet (6.2 vs. 2.9 kg; P diets. As previously reported, among women with PCOS, the lower-carbohydrate arm showed decreased fasting insulin (−2.8 μIU/mL; P < 0.001) and fasting glucose (−4.7 mg/dL; P < 0.01) and increased insulin sensitivity (1.06 arbitrary units; P < 0.05) and “dynamic” β-cell response (96.1 · 109; P < 0.001). In the lower-carbohydrate arm, women lost both IAAT (−4.8 cm2; P < 0.01) and intermuscular fat (−1.2 cm2; P < 0.01). In the lower-fat arm, women lost lean mass (−0.6 kg; P < 0.05). Original to this report, after the lower-carbohydrate arm, the change in IAAT was positively associated with the

  18. MKR mice have increased dynamic glucose disposal despite metabolic inflexibility, and hepatic and peripheral insulin insensitivity.

    Science.gov (United States)

    Vaitheesvaran, B; LeRoith, D; Kurland, I J

    2010-10-01

    Recent work has shown that there can be significant differences when glucose disposal is assessed for high-fat induced insulin resistance by static clamp methods vs dynamic assessment during a stable isotope i.p. glucose tolerance test. MKR mice, though lean, have severe insulin resistance and decreased muscle fatty acid oxidation. Our goal was to assess dynamic vs static glucose disposal in MKR mice, and to correlate glucose disposal and muscle-adipose-liver flux interactions with metabolic flexibility (indirect calorimetry) and muscle characteristics. Stable isotope flux phenotyping was performed using [6,6-(2)H(2)]glucose, [U-(13)C(6)]glucose and [2-(13)C]glycerol. Muscle triacylglycerol (TAG) and diacylglycerol (DAG) content was assessed by thin layer chromatography, and histological determination of fibre type and cytochrome c activity performed. Metabolic flexibility was assessed by indirect calorimetry. Indirect calorimetry showed that MKR mice used more glucose than FVB/N mice during fasting (respiratory exchange ratio [RER] 0.88 vs 0.77, respectively). Compared with FVB/N mice, MKR mice had faster dynamic glucose disposal, despite increased whole-muscle DAG and TAG, and similar hepatic glucose production with higher fasting insulin and unchanged basal glucose. Fed MKR muscle had more glycogen, and increased levels of GLUT1 and GLUT4 than FVB/N muscle. Histology indicated that MKR soleus had mildly decreased cytochrome c activity overall and more type II (glycolytic) fibres compared with that in FVB/N mice. MKR muscle adapts to using glucose, with more type II fibres present in red muscle. Fasting RER is elevated and glucose disposal during an i.p. glucose tolerance test is accelerated despite increased muscle DAG and TAG. Metabolic inflexibility may result from the compensatory use of fuel that can be best utilised for energy requirements; static vs dynamic glucose disposal assessments may measure complementary aspects of metabolic flexibility and insulin

  19. Capability of parasulfonato calix[6]arene, as an anion dopant, and organic solvents in enhancing the sensitivity and loading of glucose oxidase (GOx) on polypyrrole film in a biosensor: a comparative study.

    Science.gov (United States)

    Safarnavadeh, Vahideh; Zare, Karim; Fakhari, Ali Reza

    2013-11-15

    In this study, the effects of two solvents (acetonitrile and water) and an anion dopant (para sulfonato calix[6]arene ((C[6]S)(-6))), on the manufacturing and properties of a polypyrrole (Ppy)-based, glucose oxidase amperometric biosensor were studied. Pyrrole was polymerized using galvanostatic mode in two different solvents, and the effect of (C[6]S)(-6) was studied in aqueous solution. The morphology of the obtained polypyrrole films was studied by scanning electron microscopy (SEM). Glucose oxidase (GOx) was adsorbed on the Ppy films via cross-linking method. Then the amperometric responses of the Pt/Ppy/GOx electrodes were measured using the amperometric method at the potential of 0.7 V in steps of adding a glucose solution to a potassium phosphate buffer. We found that acetonitrile and (C[6]S)(-6) increase the sensitivity of the enzyme electrode up to 79.30 µA M(-1)cm(-2) in comparison with 31.60 μA M(-1)cm(-2) for the electrode synthesized in calixarene free aqueous solvent. Also (C[6]S)(-6) has the main role in preventing leaching the enzyme from the electrode. This fact increases loading of the enzyme and stability of the biosensor. So that the steady state current density of the aforementioned electrode increases linearly with increasing glucose concentration up to 190 mM. Whereas the linearity was observed up to 61 mM and 80 mM for the electrodes made using calixarene free acetonitrile and aqueous solutions, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Glucose tolerance test - non-pregnant

    Science.gov (United States)

    ... for energy. People with untreated diabetes have high blood glucose levels. Most often, the first tests used to diagnose ... in people who are not pregnant are: Fasting blood glucose level: diabetes is diagnosed if it is higher than ...

  1. Apolipoprotein E Genotype and Sex Influence Glucose Tolerance in Older Adults: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Angela J. Hanson

    2016-03-01

    Full Text Available Background: Glucose intolerance and apolipoprotein ε4 allele (E4+ are risk factors for Alzheimer's disease (AD. Insulin sensitizers show promise for treating AD, but are less effective in E4+ individuals. Little is known about how the APOE genotype influences glucose metabolism. Methods: Cross-sectional analysis of 319 older adults who underwent oral glucose tolerance tests; a subset had insulin, amyloid beta (Aβ42, and Mini Mental Status Examination. Glucose and insulin patterns with respect to cognitive diagnosis, E4 status, and sex were examined with analysis of covariance and Pearson correlation. Results: People with cognitive impairment had higher fasting insulin levels. E4 status did not affect fasting glucose values, whereas men had higher fasting glucose levels than women. E4+ men had the lowest and E4+ women had the highest glucose levels, compared to E4- groups; insulin did not differ by sex or E4 group. E4 status and sex moderated correlations between metabolic measures and AD risk factors including age and Aβ. Conclusions: Insulin resistance was associated with cognitive impairment, and sex, E4 status, and glucose values are interrelated in older adults at risk of AD. Understanding glucose metabolism for different APOE and sex groups may help elucidate differences in therapeutic responses.

  2. Increased muscle glucose uptake after exercise

    DEFF Research Database (Denmark)

    Richter, Erik; Ploug, Thorkil; Galbo, Henrik

    1985-01-01

    responsiveness of glucose uptake was noted only in controls. Analysis of intracellular glucose-6-phosphate, glucose, glycogen synthesis, and glucose transport suggested that the exercise effect on responsiveness might be due to enhancement of glucose disposal. After electrical stimulation of diabetic...... of glucose. At maximal insulin concentrations, the enhancing effect of exercise on glucose uptake may involve enhancement of glucose disposal, an effect that is probably less in muscle from diabetic rats.(ABSTRACT TRUNCATED AT 250 WORDS)......It has recently been shown that insulin sensitivity of skeletal muscle glucose uptake and glycogen synthesis is increased after a single exercise session. The present study was designed to determine whether insulin is necessary during exercise for development of these changes found after exercise...

  3. Sequence analysis and molecular characterization of Clonorchis sinensis hexokinase, an unusual trimeric 50-kDa glucose-6-phosphate-sensitive allosteric enzyme.

    Directory of Open Access Journals (Sweden)

    Tingjin Chen

    Full Text Available Clonorchiasis, which is induced by the infection of Clonorchis sinensis (C. sinensis, is highly associated with cholangiocarcinoma. Because the available examination, treatment and interrupting transmission provide limited opportunities to prevent infection, it is urgent to develop integrated strategies to prevent and control clonorchiasis. Glycolytic enzymes are crucial molecules for trematode survival and have been targeted for drug development. Hexokinase of C. sinensis (CsHK, the first key regulatory enzyme of the glycolytic pathway, was characterized in this study. The calculated molecular mass (Mr of CsHK was 50.0 kDa. The obtained recombinant CsHK (rCsHK was a homotrimer with an Mr of approximately 164 kDa, as determined using native PAGE and gel filtration. The highest activity was obtained with 50 mM glycine-NaOH at pH 10 and 100 mM Tris-HCl at pH 8.5 and 10. The kinetics of rCsHK has a moderate thermal stability. Compared to that of the corresponding negative control, the enzymatic activity was significantly inhibited by praziquantel (PZQ and anti-rCsHK serum. rCsHK was homotropically and allosterically activated by its substrates, including glucose, mannose, fructose, and ATP. ADP exhibited mixed allosteric effect on rCsHK with respect to ATP, while inorganic pyrophosphate (PPi displayed net allosteric activation with various allosteric systems. Fructose behaved as a dose-dependent V activator with the substrate glucose. Glucose-6-phosphate (G6P displayed net allosteric inhibition on rCsHK with respect to ATP or glucose with various allosteric systems in a dose-independent manner. There were differences in both mRNA and protein levels of CsHK among the life stages of adult worm, metacercaria, excysted metacercaria and egg of C. sinensis, suggesting different energy requirements during different development stages. Our study furthers the understanding of the biological functions of CsHK and supports the need to screen for small

  4. Sequence Analysis and Molecular Characterization of Clonorchis sinensis Hexokinase, an Unusual Trimeric 50-kDa Glucose-6-Phosphate-Sensitive Allosteric Enzyme

    Science.gov (United States)

    Chen, Tingjin; Ning, Dan; Sun, Hengchang; Li, Ran; Shang, Mei; Li, Xuerong; Wang, Xiaoyun; Chen, Wenjun; Liang, Chi; Li, Wenfang; Mao, Qiang; Li, Ye; Deng, Chuanhuan; Wang, Lexun; Wu, Zhongdao; Huang, Yan; Xu, Jin; Yu, Xinbing

    2014-01-01

    Clonorchiasis, which is induced by the infection of Clonorchis sinensis (C. sinensis), is highly associated with cholangiocarcinoma. Because the available examination, treatment and interrupting transmission provide limited opportunities to prevent infection, it is urgent to develop integrated strategies to prevent and control clonorchiasis. Glycolytic enzymes are crucial molecules for trematode survival and have been targeted for drug development. Hexokinase of C. sinensis (CsHK), the first key regulatory enzyme of the glycolytic pathway, was characterized in this study. The calculated molecular mass (Mr) of CsHK was 50.0 kDa. The obtained recombinant CsHK (rCsHK) was a homotrimer with an Mr of approximately 164 kDa, as determined using native PAGE and gel filtration. The highest activity was obtained with 50 mM glycine-NaOH at pH 10 and 100 mM Tris-HCl at pH 8.5 and 10. The kinetics of rCsHK has a moderate thermal stability. Compared to that of the corresponding negative control, the enzymatic activity was significantly inhibited by praziquantel (PZQ) and anti-rCsHK serum. rCsHK was homotropically and allosterically activated by its substrates, including glucose, mannose, fructose, and ATP. ADP exhibited mixed allosteric effect on rCsHK with respect to ATP, while inorganic pyrophosphate (PPi) displayed net allosteric activation with various allosteric systems. Fructose behaved as a dose-dependent V activator with the substrate glucose. Glucose-6-phosphate (G6P) displayed net allosteric inhibition on rCsHK with respect to ATP or glucose with various allosteric systems in a dose-independent manner. There were differences in both mRNA and protein levels of CsHK among the life stages of adult worm, metacercaria, excysted metacercaria and egg of C. sinensis, suggesting different energy requirements during different development stages. Our study furthers the understanding of the biological functions of CsHK and supports the need to screen for small molecule inhibitors

  5. Accurate and sensitive determination of molar fractions of "1"3C-Labeled intracellular metabolites in cell cultures grown in the presence of isotopically-labeled glucose

    International Nuclear Information System (INIS)

    Fernández-Fernández, Mario; Rodríguez-González, Pablo; Hevia Sánchez, David; González-Menéndez, Pedro; Sainz Menéndez, Rosa M.; García Alonso, J. Ignacio

    2017-01-01

    This work describes a methodology based on multiple linear regression and GC-MS for the determination of molar fractions of isotopically-labeled intracellular metabolites in cell cultures. Novel aspects of this work are: i) the calculation of theoretical isotopic distributions of the different isotopologues from an experimentally measured value of % 13C enrichment of the labeled precursor ii) the calculation of the contribution of lack of mass resolution of the mass spectrometer and different fragmentation mechanism such as the loss or gain of hydrogen atoms in the EI source to measure the purity of the selected cluster for each metabolite and iii) the validation of the methodology not only by the analysis of gravimetrically prepared mixtures of isotopologues but also by the comparison of the obtained molar fractions with experimental values obtained by GC-Combustion-IRMS based on "1"3C/"1"2C isotope ratio measurements. The method is able to measure molar fractions for twenty-eight intracellular metabolites derived from glucose metabolism in cell cultures grown in the presence of "1"3C-labeled Glucose. The validation strategies demonstrate a satisfactory accuracy and precision of the proposed procedure. Also, our results show that the minimum value of "1"3C incorporation that can be accurately quantified is significantly influenced by the calculation of the spectral purity of the measured cluster and the number of "1"3C atoms of the labeled precursor. The proposed procedure was able to accurately quantify gravimetrically prepared mixtures of natural and labeled glucose molar fractions of 0.07% and mixtures of natural and labeled glycine at molar fractions down to 0.7%. The method was applied to initial studies of glucose metabolism of different prostate cancer cell lines. - Highlights: • Determination of molar fractions of "1"3C-labeled metabolites in cell cultures. • The method is based on multiple linear regression and GC-MS. • Validation of the method by

  6. Accurate and sensitive determination of molar fractions of {sup 13}C-Labeled intracellular metabolites in cell cultures grown in the presence of isotopically-labeled glucose

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Fernández, Mario [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo (Spain); Rodríguez-González, Pablo, E-mail: rodriguezpablo@uniovi.es [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo (Spain); Hevia Sánchez, David; González-Menéndez, Pedro; Sainz Menéndez, Rosa M. [University Institute of Oncology (IUOPA), University of Oviedo, Julián Clavería 6, 33006 Oviedo (Spain); García Alonso, J. Ignacio [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo (Spain)

    2017-05-29

    This work describes a methodology based on multiple linear regression and GC-MS for the determination of molar fractions of isotopically-labeled intracellular metabolites in cell cultures. Novel aspects of this work are: i) the calculation of theoretical isotopic distributions of the different isotopologues from an experimentally measured value of % 13C enrichment of the labeled precursor ii) the calculation of the contribution of lack of mass resolution of the mass spectrometer and different fragmentation mechanism such as the loss or gain of hydrogen atoms in the EI source to measure the purity of the selected cluster for each metabolite and iii) the validation of the methodology not only by the analysis of gravimetrically prepared mixtures of isotopologues but also by the comparison of the obtained molar fractions with experimental values obtained by GC-Combustion-IRMS based on {sup 13}C/{sup 12}C isotope ratio measurements. The method is able to measure molar fractions for twenty-eight intracellular metabolites derived from glucose metabolism in cell cultures grown in the presence of {sup 13}C-labeled Glucose. The validation strategies demonstrate a satisfactory accuracy and precision of the proposed procedure. Also, our results show that the minimum value of {sup 13}C incorporation that can be accurately quantified is significantly influenced by the calculation of the spectral purity of the measured cluster and the number of {sup 13}C atoms of the labeled precursor. The proposed procedure was able to accurately quantify gravimetrically prepared mixtures of natural and labeled glucose molar fractions of 0.07% and mixtures of natural and labeled glycine at molar fractions down to 0.7%. The method was applied to initial studies of glucose metabolism of different prostate cancer cell lines. - Highlights: • Determination of molar fractions of {sup 13}C-labeled metabolites in cell cultures. • The method is based on multiple linear regression and GC-MS.

  7. Self-reported discrimination, diabetes distress, and continuous blood glucose in women with type 2 diabetes.

    Science.gov (United States)

    Wagner, Julie A; Tennen, Howard; Feinn, Richard; Osborn, Chandra Y

    2015-04-01

    We investigated whether self-reported racial discrimination was associated with continuous glucose levels and variability in individuals with diabetes, and whether diabetes distress mediated these associations. Seventy-four Black and White women with type 2 diabetes completed the Experience of Discrimination scale, a measure of lifetime racial discrimination, and the Problem Areas in Diabetes, a measure of diabetes distress. Participants wore a continuous glucose monitor for 24 h after 8 h of fasting, a standard meal, and a 4-h run in period. Higher discrimination predicted higher continuous mean glucose and higher standard deviation of glucose. For both mean and standard deviation of glucose, a race × discrimination interaction indicated a stronger relationship between discrimination and glucose for Whites than for Blacks. Diabetes distress mediated the discrimination-mean glucose relationship. Whites who report discrimination may be uniquely sensitive to distress. These preliminary findings suggest that racial discrimination adversely affects glucose control in women with diabetes, and does so indirectly through diabetes distress. Diabetes distress may be an important therapeutic target to reduce the ill effects of racial discrimination in persons with diabetes.

  8. Intermittent hypoxia impairs glucose homeostasis in C57BL6/J mice: partial improvement with cessation of the exposure.

    Science.gov (United States)

    Polak, Jan; Shimoda, Larissa A; Drager, Luciano F; Undem, Clark; McHugh, Holly; Polotsky, Vsevolod Y; Punjabi, Naresh M

    2013-10-01

    Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued. C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed. Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted. Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism.

  9. Liraglutide effects on beta-cell, insulin sensitivity and glucose effectiveness in patients with stable coronary artery disease and newly diagnosed type 2 diabetes

    DEFF Research Database (Denmark)

    Anholm, Christian; Kumarathurai, Preman; Pedersen, Lene R.

    2017-01-01

    characteristics were: HbA1c 47 mmol/mol (SD 6), BMI 31.6 kg/m2 (SD 4.8), fasting plasma-glucose 6.9 mmol/L (IQR 6.1; 7.4) and HOMA-IR 4.9 (IQR 3.0; 7.5). Liraglutide treatment improved AIRg by 3-fold, 497 mU × L−1 × min (IQR 342; 626, P ... weight loss of −2.7 kg (−6.7; −0.6) during liraglutide treatment, we found no improvement in HOMA-IR, Si or Sg. Weight loss during liraglutide therapy did not result in a carry-over effect. Conclusion: Liraglutide as add-on to metformin induces a clinically significant improvement in beta-cell function...

  10. Genetic Variations in the Kir6.2 Subunit (KCNJ11 of Pancreatic ATP-Sensitive Potassium Channel Gene Are Associated with Insulin Response to Glucose Loading and Early Onset of Type 2 Diabetes in Childhood and Adolescence in Taiwan

    Directory of Open Access Journals (Sweden)

    Yi-Der Jiang

    2014-01-01

    Full Text Available To investigate the role of E23K polymorphism of the KCNJ11 gene on early onset of type 2 diabetes in school-aged children/adolescents in Taiwan, we recruited 38 subjects with type 2 diabetes (ages 18.6 ± 6.6 years; body mass index percentiles 83.3 ± 15.4 and 69 normal controls (ages 17.3 ± 3.8 years; body mass index percentiles 56.7 ± 29.0 from a national surveillance for childhood/adolescent diabetes in Taiwan. We searched for the E23K polymorphism of the KCNJ11 gene. We found that type 2 diabetic subjects had higher carrier rate of E23K polymorphism of KCNJ11 gene than control subjects (P = 0.044. After adjusting for age, gender, body mass index percentiles, and fasting plasma insulin, the E23K polymorphism contributed to an increased risk for type 2 diabetes (P = 0.047. K23-allele-containing genotypes conferring increased plasma insulin level during OGTT in normal subjects. However, the diabetic subjects with the K23-allele-containing genotypes had lower fasting plasma insulin levels after adjustment of age and BMI percentiles. In conclusion, the E23K variant of the KCNJ11 gene conferred higher susceptibility to type 2 diabetes in children/adolescents. Furthermore, in normal glucose-tolerant children/adolescents, K23 allele carriers had a higher insulin response to oral glucose loading.

  11. Association of Androgen Excess with Glucose Intolerance in Women with Polycystic Ovary Syndrome

    Directory of Open Access Journals (Sweden)

    Bingjie Zhang

    2018-01-01

    Full Text Available Women with polycystic ovary syndrome (PCOS show high prevalence of glucose intolerance. This study aimed to investigate the association of androgen excess with glucose intolerance in PCOS. A total of 378 women with PCOS participated in the study. Free androgen index (FAI was selected as indicator of hyperandrogenism. Insulin sensitivity was assessed by 1/homeostasis model assessment of insulin resistance (1/HOMA-IR and Matsuda insulin sensitivity index (ISIM; β-cell function was assessed by disposition index (DI. We found that women with glucose intolerance had higher FAI levels compared to women with normal glucose tolerance (NGT (prediabetes 6.2, T2DM 7.9 versus NGT 5.0, resp.; p<0.001. Furthermore, there was a direct association between FAI levels and frequency of glucose intolerance (OR = 2.480, 95% CI 1.387–4.434, even after adjusting for age, BMI, waist circumference, hypertension, fasting insulin, testosterone, SHBG, and family history of diabetes. In addition, with FAI increase, glycosylated hemoglobin (HbA1c, plasma glucose concentrations, and serum insulin levels increased, while insulin sensitivity and β-cell function decreased. Our results suggested that androgen excess indicated by high FAI levels might serve as indicator of glucose intolerance, as it might promote insulin resistance and β-cell dysfunction in women with PCOS.

  12. Elevated 1-h post-challenge plasma glucose levels in subjects with normal glucose tolerance or impaired glucose tolerance are associated with whole blood viscosity.

    Science.gov (United States)

    Marini, Maria Adelaide; Fiorentino, Teresa Vanessa; Andreozzi, Francesco; Mannino, Gaia Chiara; Perticone, Maria; Sciacqua, Angela; Perticone, Francesco; Sesti, Giorgio

    2017-08-01

    It has been suggested that glucose levels ≥155 mg/dl at 1-h during an oral glucose tolerance test (OGTT) may predict development of type 2 diabetes and cardiovascular events among adults with normal glucose tolerance (NGT 1 h-high). Studies showed a link between increased blood viscosity and type 2 diabetes. However, whether blood viscosity is associated with dysglycemic conditions such as NGT 1 h-high, impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) is unsettled. 1723 non-diabetic adults underwent biochemical evaluation and OGTT. A validated formula based on hematocrit and total plasma proteins was employed to estimate whole blood viscosity. Subjects were categorized into NGT with 1 h glucose h-low), NGT-1 h-high, IFG and/or IGT. Hematocrit and blood viscosity values appeared significantly higher in individuals with NGT 1 h-high, IFG and/or IGT as compared to NGT 1 h-low subjects. Blood viscosity was significantly correlated with age, waist circumference, blood pressure, HbA1c, fasting, 1- and 2-h post-challenge insulin levels, total cholesterol and low-density lipoprotein, triglycerides, fibrinogen, white blood cell, and inversely correlated with high-density lipoprotein and insulin sensitivity. Of the four glycemic parameters, 1-h post-challenge glucose showed the strongest correlation with blood viscosity (β = 0.158, P h post-challenge plasma glucose. They also suggest that a subgroup of NGT individuals with 1-h post-challenge plasma >155 mg/dl have increased blood viscosity comparable to that observed in subjects with IFG and/or IGT.

  13. Identification of the common radiation-sensitive and glucose metabolism-related expressed genes in the thymus of ICR and AKR/J mice

    International Nuclear Information System (INIS)

    Bong, Jin Jong; Kang, Yumi; Choi, Suk Cjul; Choi, Moo Hyun; Choi, Seung Jin; Kim, Hee Sun

    2011-01-01

    Our goal was to identify the common radiation-sensitive expressed genes in the thymus of ICR and AKR/J mice on 100 days after irradiation. Thus, we performed microarray analysis for thymus of ICR and AKR/J mice, respectively. We categorized differential expressed genes by the analysis of DAVID Bioinformatics Resources v 6.7 and GeneSpring GX 11.5.1 and validated gene expression patterns by QPCR analysis. Our result demonstrated that radiation-sensitive expressed genes and signaling pathways in the thymus of irradiated ICR and AKR/J mice.

  14. Glucose oxidase-graphene-chitosan modified electrode for direct electrochemistry and glucose sensing

    International Nuclear Information System (INIS)

    Kang, Xinhuang; Wang, Jun; Wu, Hong; Aksay, Ilhan A.; Liu, Jun; Lin, Yuehe

    2009-01-01

    Direct electrochemistry of a glucose oxidase (GOD)/graphene/chitosan nanocomposite was studied. The immobilized enzyme retains its bioactivity, exhibits a surface confined, reversible two-proton and two-electron transfer reaction, and has good stability, activity and a fast heterogeneous electron transfer rate with the rate constant (k s ) of 2.83 s -1 . A much higher enzyme loading (1.12 x 10 -9 mol/cm 2 ) is obtained as compared to the bare glass carbon surface. This GOD/graphene/chitosan nanocomposite film can be used for sensitive detection of glucose. The biosensor exhibits a wider linearity range from 0.08 mM to 12 mM glucose with a detection limit of 0.02 mM and much higher sensitivity (37.93 (micro)A mM -1 cm -2 ) as compared with other nanostructured supports. The excellent performance of the biosensor is attributed to large surface-to-volume ratio and high conductivity of graphene, and good biocompatibility of chitosan, which enhances the enzyme absorption and promotes direct electron transfer between redox enzymes and the surface of electrodes.

  15. Enhanced non-enzymatic glucose sensing based on copper nanoparticles decorated nitrogen-doped graphene.

    Science.gov (United States)

    Jiang, Ding; Liu, Qian; Wang, Kun; Qian, Jing; Dong, Xiaoya; Yang, Zhenting; Du, Xiaojiao; Qiu, Baijing

    2014-04-15

    Copper nanoparticles (NPs) decorated nitrogen-doped graphene (Cu-N-G) was prepared by a facile thermal treatment, and further employed as a novel sensing material for fabricating the sensitive non-enzymatic glucose sensor. Compared with pure Cu NPs, the Cu-N-G showed enhanced electrocatalytic activity to glucose oxidation due to the integration of N-G, which exhibited the oxidation peak current of glucose ca. 23-fold higher than that of pure Cu NPs. The presented sensor showed excellent performances for glucose detection including wide linear range of 0.004-4.5 mM, low detection limit (1.3 μM, S/N=3), high sensitivity (48.13 μA mM(-1)), fast response time (doped graphene as enhanced materials in fabricating sensors for chemical and biochemical analysis. © 2013 Published by Elsevier B.V.

  16. Decreased insulin clearance in individuals with elevated 1-h post-load plasma glucose levels.

    Directory of Open Access Journals (Sweden)

    Maria Adelaide Marini

    Full Text Available Reduced insulin clearance has been shown to predict the development of type 2 diabetes. Recently, it has been suggested that plasma glucose concentrations ≥ 8.6 mmol/l (155 mg/dl at 1 h during an oral glucose tolerance test (OGTT can identify individuals at high risk for type 2 diabetes among those who have normal glucose tolerance (NGT 1 h-high. The aim of this study was to examine whether NGT 1 h-high have a decrease in insulin clearance, as compared with NGT individuals with 1-h post-load glucose <8.6 mmol/l (l (155 mg/dl, NGT 1 h-low. To this end, 438 non-diabetic White individuals were subjected to OGTT and euglycemic-hyperinsulinemic clamp to evaluate insulin clearance and insulin sensitivity. As compared with NGT 1 h-low individuals, NGT 1 h-high had significantly higher 1-h and 2-h post-load plasma glucose and 2-h insulin levels as well as higher fasting glucose and insulin levels. NGT 1 h-high exhibited also a significant decrease in both insulin sensitivity (P<0.0001 and insulin clearance (P = 0.006 after adjusting for age, gender, adiposity measures, and insulin sensitivity. The differences in insulin clearance remained significant after adjustment for fasting glucose (P = 0.02 in addition to gender, age, and BMI. In univariate analyses adjusted for gender and age, insulin clearance was inversely correlated with body weight, body mass index, waist, fat mass, 1-h and 2-h post-load glucose levels, fasting, 1-h and 2-h post-load insulin levels, and insulin-stimulated glucose disposal. In conclusion, our data show that NGT 1 h-high have a reduction in insulin clearance as compared with NGT 1 h-low individuals; this suggests that impaired insulin clearance may contribute to sustained fasting and post-meal hyperinsulinemia.

  17. miR-125b acts as a tumor suppressor in chondrosarcoma cells by the sensitization to doxorubicin through direct targeting the ErbB2-regulated glucose metabolism.

    Science.gov (United States)

    Tang, Xian-ye; Zheng, Wei; Ding, Min; Guo, Kai-jin; Yuan, Feng; Feng, Hu; Deng, Bin; Sun, Wei; Hou, Yang; Gao, Lu

    2016-01-01

    Chondrosarcoma is the second most common type of primary bone malignancy in the United States after osteosarcoma. Surgical resections of these tumors are the only effective treatment to chondrosarcoma patients due to their resistance to conventional chemo- and radiotherapy. In this study, miR-125b was found to perform its tumor-suppressor function to inhibit glucose metabolism via the direct targeting of oncogene, ErbB2. We report miR-125b was downregulated in both chondrosarcoma patient samples and cell lines. The total 20 Asian chondrosarcoma patients showed significantly downregulated miR-125b expression compared with normal tissues. Meanwhile, miR-125 was downregulated in chondrosarcoma cells and doxorubicin resistant cells. Overexpression of miR-125 enhanced the sensitivity of both parental and doxorubicin resistant cells to doxorubicin through direct targeting on the ErbB2-mediated upregulation of glycolysis in chondrosarcoma cells. Moreover, restoration of the expression of ErbB2 and glucose metabolic enzymes in miR-125 pretransfected cells recovered the susceptibility to doxorubicin. Our study will provide a novel aspect on the overcoming chemoresistance in human chondrosarcoma cells and may help in the development of therapeutic strategies for the treatments of patients.

  18. Glucose metabolism in lactating reindeer

    Energy Technology Data Exchange (ETDEWEB)

    White, R G; Luick, J R

    1976-01-01

    Changes in glucose synthesis during the lactation cycle were estimated in pen-fed and grazing reindeer. The pool size, space, transfer rate, and irreversible loss of glucose were determined using simultaneous injections of (2-/sup 3/H)glucose and primed infusions of (U-/sup 14/C)glucose in reindeer lactating for 1-2, 4-5, 8-9, and 12-16 weeks. Glucose transfer rate and irreversible loss were higher during early to midlactation than at other times of the year; maximum estimates were at 8-9 week postpartum (July), and a decline was noted at 12-16 weeks (August). During the first 1-2 weeks in pen-fed and 4-5 weeks in grazing reindeer, glucose transfer rate and irreversible loss were almost twice the values reported for reindeer at maintenance. No difference in the irreversible loss of glucose was noted between lactating and non-lactating reindeer at 18-20 weeks postpartum (September), and there is evidence that this may occur as early as 12-16 weeks postpartum. No significant trend was noted in the glucose space throughout lactation; however, a significant increase in plasma glucose concentration and pool size was noted when glucose synthesis was highest (8-9 weeks postpartum). Glucose turnover time was consistently faster (78-88 min) in lactating than in non-lactating reindeer (107-140 min). Reindeer used a smaller proportion of plasma glucose-C for lactose synthesis than did other domestic species. This probably results from the low lactose content of reindeer milk and the relatively low rate of milk secretion. (auth)

  19. Activation of the AMPK/Sirt1 pathway by a leucine-metformin combination increases insulin sensitivity in skeletal muscle, and stimulates glucose and lipid metabolism and increases life span in Caenorhabditis elegans.

    Science.gov (United States)

    Banerjee, Jheelam; Bruckbauer, Antje; Zemel, Michael B

    2016-11-01

    We have previously shown leucine (Leu) to activate Sirt1 by lowering its K M for NAD + , thereby amplifying the effects of other sirtuin activators and improving insulin sensitivity. Metformin (Met) converges on this pathway both indirectly (via AMPK) and by direct activation of Sirt1, and we recently found Leu to synergize with Met to improve insulin sensitivity and glycemic control while achieving ~80% dose-reduction in diet-induced obese mice. Accordingly, we sought here to define the mechanism of this interaction. Muscle cells C2C12 and liver cells HepG2 were used to test the effect of Met-Leu on Sirt1 activation. Caenorhabditis elegans was used for glucose utilization and life span studies. Leu (0.5mmol/L)+Met (50-100μmol/L) synergistically activated Sirt1 (pmetformin exerted no independent effect at any concentration (0.1-0.5mmol/L). Thus, Leu and Met synergize to enable Sirt1 activation at low NAD + concentrations (typical of energy replete states). Sirt1 and AMPK activations are required for Met-Leu's full action, which result in improvements in energy metabolism and insulin sensitivity. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Using global sensitivity analysis to understand higher order interactions in complex models: an application of GSA on the Revised Universal Soil Loss Equation (RUSLE) to quantify model sensitivity and implications for ecosystem services management in Costa Rica

    Science.gov (United States)

    Fremier, A. K.; Estrada Carmona, N.; Harper, E.; DeClerck, F.

    2011-12-01

    Appropriate application of complex models to estimate system behavior requires understanding the influence of model structure and parameter estimates on model output. To date, most researchers perform local sensitivity analyses, rather than global, because of computational time and quantity of data produced. Local sensitivity analyses are limited in quantifying the higher order interactions among parameters, which could lead to incomplete analysis of model behavior. To address this concern, we performed a GSA on a commonly applied equation for soil loss - the Revised Universal Soil Loss Equation. USLE is an empirical model built on plot-scale data from the USA and the Revised version (RUSLE) includes improved equations for wider conditions, with 25 parameters grouped into six factors to estimate long-term plot and watershed scale soil loss. Despite RUSLE's widespread application, a complete sensitivity analysis has yet to be performed. In this research, we applied a GSA to plot and watershed scale data from the US and Costa Rica to parameterize the RUSLE in an effort to understand the relative importance of model factors and parameters across wide environmental space. We analyzed the GSA results using Random Forest, a statistical approach to evaluate parameter importance accounting for the higher order interactions, and used Classification and Regression Trees to show the dominant trends in complex interactions. In all GSA calculations the management of cover crops (C factor) ranks the highest among factors (compared to rain-runoff erosivity, topography, support practices, and soil erodibility). This is counter to previous sensitivity analyses where the topographic factor was determined to be the most important. The GSA finding is consistent across multiple model runs, including data from the US, Costa Rica, and a synthetic dataset of the widest theoretical space. The three most important parameters were: Mass density of live and dead roots found in the upper inch

  1. Continuous glucose monitoring, oral glucose tolerance, and insulin - glucose parameters in adolescents with simple obesity.

    Science.gov (United States)

    El Awwa, A; Soliman, A; Al-Ali, M; Yassin, M; De Sanctis, V

    2012-09-01

    In obese adolescents pancreatic beta-cells may not be able to cope with insulin resistance leading to hyperglycemia and type2 diabetes (T2DM To assess oral glucose tolerance, 72-h continuous blood glucose concentrations (CGM) and calculate homeostatic model assessment (HOMA), and the quantitative insulin sensitivity check index (QUICKI) in 13 adolescents with simple obesity (BMI SDS=4 ± 1.06). OGTT performed in 13 obese adolescents (13.47 ± 3 years) revealed 3 cases (23%) with impaired fasting glucose (IFG: fasting glucose >5.6 mmol/L), 4 cases (30%) with impaired glucose tolerance (IGT: 2h blood glucose >7.8 continuous glucose monitoring system ( CGMS), IFG was detected in 4 cases, the maximum serum blood glucose (BG : 2h or more after meal) was >7.8 and 11.1 mmol/L (diabetes) in one case (7.6%). Five cases had a minimum BG recorded of 2.6 and QUICKI values obese adolescents, CGMS is superior to OGTT and HbA1C in detecting glycemic abnormalities, which appears to be secondary to insulin resistance.

  2. Neuroscience of glucose homeostasis

    NARCIS (Netherlands)

    La Fleur, S E; Fliers, E; Kalsbeek, A

    2014-01-01

    Plasma glucose concentrations are homeostatically regulated and maintained within strict boundaries. Several mechanisms are in place to increase glucose output when glucose levels in the circulation drop as a result of glucose utilization, or to decrease glucose output and increase tissue glucose

  3. Amperometric glucose biosensor based on glucose oxidase dispersed in multiwalled carbon nanotubes/graphene oxide hybrid biocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Palanisamy, Selvakumar; Cheemalapati, Srikanth; Chen, Shen-Ming, E-mail: smchen78@ms15.hinet.net

    2014-01-01

    An amperometric glucose biosensor based on enhanced and fast direct electron transfer (DET) of glucose oxidase (GOx) at enzyme dispersed multiwalled carbon nanotubes/graphene oxide (MWCNT/GO) hybrid biocomposite was developed. The fabricated hybrid biocomposite was characterized by transmission electron microscopy (TEM), Raman and infrared spectroscopy (IR). The TEM image of hybrid biocomposite reveals that a thin layer of GOx was covered on the surface of MWCNT/GO hybrid composite. IR results validate that the hybrid biocomposite was formed through the electrostatic interactions between GOx and MWCNT/GO hybrid composite. Further, MWCNT/GO hybrid composite has also been characterized by TEM and UV–visible spectroscopy. A pair of well-defined redox peak was observed for GOx immobilized at the hybrid biocomposite electrode than that immobilized at the MWCNT modified electrode. The electron transfer rate constant (K{sub s}) of GOx at the hybrid biocomposite was calculated to be 11.22 s{sup −1}. The higher K{sub s} value revealed that fast DET of GOx occurred at the electrode surface. Moreover, fabricated biosensor showed a good sensitivity towards glucose oxidation over a linear range 0.05–23.2 mM. The limit of detection (LOD) was estimated to be 28 μM. The good features of the proposed biosensor could be used for the accurate detection of glucose in the biological samples. - Highlights: • An amperometric glucose biosensor has been developed at MWCNT/GO hybrid biocomposite. • Enhanced and fast direct electron transfer kinetics of glucose oxidase has been achieved at hybrid biocomposite. • Hybrid biocomposite has been characterized by TEM, IR and Raman spectroscopy. • Highly sensitive and selective for glucose determination.

  4. Amperometric glucose biosensor based on glucose oxidase dispersed in multiwalled carbon nanotubes/graphene oxide hybrid biocomposite

    International Nuclear Information System (INIS)

    Palanisamy, Selvakumar; Cheemalapati, Srikanth; Chen, Shen-Ming

    2014-01-01

    An amperometric glucose biosensor based on enhanced and fast direct electron transfer (DET) of glucose oxidase (GOx) at enzyme dispersed multiwalled carbon nanotubes/graphene oxide (MWCNT/GO) hybrid biocomposite was developed. The fabricated hybrid biocomposite was characterized by transmission electron microscopy (TEM), Raman and infrared spectroscopy (IR). The TEM image of hybrid biocomposite reveals that a thin layer of GOx was covered on the surface of MWCNT/GO hybrid composite. IR results validate that the hybrid biocomposite was formed through the electrostatic interactions between GOx and MWCNT/GO hybrid composite. Further, MWCNT/GO hybrid composite has also been characterized by TEM and UV–visible spectroscopy. A pair of well-defined redox peak was observed for GOx immobilized at the hybrid biocomposite electrode than that immobilized at the MWCNT modified electrode. The electron transfer rate constant (K s ) of GOx at the hybrid biocomposite was calculated to be 11.22 s −1 . The higher K s value revealed that fast DET of GOx occurred at the electrode surface. Moreover, fabricated biosensor showed a good sensitivity towards glucose oxidation over a linear range 0.05–23.2 mM. The limit of detection (LOD) was estimated to be 28 μM. The good features of the proposed biosensor could be used for the accurate detection of glucose in the biological samples. - Highlights: • An amperometric glucose biosensor has been developed at MWCNT/GO hybrid biocomposite. • Enhanced and fast direct electron transfer kinetics of glucose oxidase has been achieved at hybrid biocomposite. • Hybrid biocomposite has been characterized by TEM, IR and Raman spectroscopy. • Highly sensitive and selective for glucose determination

  5. Noradrenaline and acetylcholine responsiveness of glucose-monitoring and glucose-insensitive neurons in the mediodorsal prefrontal cortex.

    Science.gov (United States)

    Nagy, Bernadett; Szabó, István; Csetényi, Bettina; Hormay, Edina; Papp, Szilárd; Keresztes, Dóra; Karádi, Zoltán

    2014-01-16

    The mediodorsal prefrontal cortex (mdPFC), as part of the forebrain glucose-monitoring (GM) system, plays important role in several regulatory processes to control the internal state of the organism and to initiate behavioral outputs accordingly. Little is known, however, about the neurochemical sensitivity of neurons located in this area. Substantial evidence indicates that the locus ceruleus - noradrenaline (NA) projection system and the nucleus basalis magnocellularis - cholinergic projection system regulate behavioral state and state dependent processing of sensory information, various cognitive functions already associated with the mdPFC. The main goal of the present study was to examine noradrenergic and cholinergic responsiveness of glucose-monitoring and glucose-insensitive (GIS) neurons in the mediodorsal prefrontal cortex. One fifth of the neurons tested changed in firing rate to microelectrophoretically applied NA. Responsiveness of the GM cells to this catecholamine proved to be significantly higher than that of the GIS units. Microiontophoretic application of acetylcholine (Ach) resulted in activity changes (predominantly facilitation) of more than 40% of the mdPFC neurons. Proportion of Ach sensitive units among the GM and the GIS neurons was found to be similar. The glucose-monitoring neurons of the mdPFC and their distinct NA and remarkable Ach sensitivity are suggested to be of particular significance in prefrontal control of adaptive behaviors. © 2013 Published by Elsevier B.V.

  6. Nonsuppressed Glucagon After Glucose Challenge as a Potential Predictor for Glucose Tolerance.

    Science.gov (United States)

    Wagner, Róbert; Hakaste, Liisa H; Ahlqvist, Emma; Heni, Martin; Machann, Jürgen; Schick, Fritz; Van Obberghen, Emmanuel; Stefan, Norbert; Gallwitz, Baptist; Tuomi, Tiinamaija; Häring, Hans-Ulrich; Groop, Leif; Fritsche, Andreas

    2017-05-01

    Glucagon levels are classically suppressed after glucose challenge. It is still not clear as to whether a lack of suppression contributes to hyperglycemia and thus to the development of diabetes. We investigated the association of postchallenge change in glucagon during oral glucose tolerance tests (OGTTs), hypothesizing that higher postchallenge glucagon levels are observed in subjects with impaired glucose tolerance (IGT). Glucagon levels were measured during OGTT in a total of 4,194 individuals without diabetes in three large European cohorts. Longitudinal changes in glucagon suppression were investigated in 50 participants undergoing a lifestyle intervention. Only 66-79% of participants showed suppression of glucagon at 120 min (fold change glucagon 120/0 change glucagon 120/0 ≥1). Participants with nonsuppressed glucagon 120 had a lower risk of IGT in all cohorts (odds ratio 0.44-0.53, P change glucagon 120/0 was associated with an improvement in insulin sensitivity ( P = 0.003). We characterize nonsuppressed glucagon 120 during the OGTT. Lower glucagon suppression after oral glucose administration is associated with a metabolically healthier phenotype, suggesting that it is not an adverse phenomenon. © 2017 by the American Diabetes Association.

  7. Insulin secretion and insulin resistance in Korean women with gestational diabetes mellitus and impaired glucose tolerance.

    Science.gov (United States)

    Yang, Sae Jeong; Kim, Tae Nyun; Baik, Sei Hyun; Kim, Tae Sun; Lee, Kwan Woo; Nam, Moonsuk; Park, Yong Soo; Woo, Jeong-Teak; Kim, Young Seol; Kim, Sung-Hoon

    2013-05-01

    The aim was to compare the insulin sensitivity and secretion index of pregnant Korean women with normal glucose tolerance (NGT), gestational impaired glucose tolerance (GIGT; only one abnormal value according to the Carpenter and Coustan criteria), and gestational diabetes mellitus (GDM). A cross-sectional study was performed with 1,163 pregnant women with positive (1-hour plasma glucose ≥ 7.2 mmol/L) in a 50-g oral glucose challenge test (OGCT). The 100-g oral glucose tolerance test (OGTT) was used to stratify the participants into three groups: NGT (n = 588), GIGT (n = 294), and GDM (n = 281). The GDM group had higher homeostasis model assessment of insulin resistance and lower insulin sensitivity index (ISOGTT), quantitative insulin sensitivity check index, homeostasis model assessment for estimation of index β-cell secretion (HOMA-B), first and second phase insulin secretion, and insulin secretion-sensitivity index (ISSI) than the NGT group (p ≤ 0.001 for all). Moreover, the GIGT group had lower ISOGTT, HOMA-B, first and second phase insulin secretion, and ISSI than the NGT group (p insulin secretion status than the 3-hour abnormal levels group. Korean women with GDM show impairments of both insulin secretion and insulin sensitivity. In addition, GIGT is associated with both β-cell dysfunction and insulin resistance.

  8. T-regulatory cells depletion is the main cause for enhanced antitumor immunity during radio-sensitization of tumors by 2-deoxy-D-glucose

    International Nuclear Information System (INIS)

    Farooque, Abdullah; Verma, Amit; Singh, Niharika; Chauhan, Sachin Kumar Singh; Jethani, Jyoti; Adhikari, J.S.; Dwarakanath, B.S.; Afrin, Farhat

    2014-01-01

    Regulatory T cells (Tregs) are known to have profound effects in blocking anti-tumor immunity. Therefore, Tregs are seen as a major hurdle that must be overcome in order to improve the efficacy of cancer therapy. The glycolytic inhibitor, 2-deoxy-d-glucose (2-DG) enhances radiation and chemotherapeutics induced death of many cancer cells in vitro and local tumor control in vivo, which was found to be associated with the enhanced anti-tumor immunity. Therefore, we investigated the role of Tregs in determining the tumor response to the combined treatment of 2-DG plus ionizing radiation. Ehrlich ascites tumor bearing mice were administered with a single dose of 2-DG (2 gm/Kg/b.wt) intravenously just before focal irradiation (10 Gy). Immuno-phenotyping of Tregs in secondary lymphoid organs was carried out using flow cytometry, while related cytokines were analyzed using bead array and ELISA. Further, mRNA and protein levels of transcription factors were assessed in sorted splenic CD4 + cells and CD4 + CD25 + using real time PCR and Western blot techniques. Results clearly showed depletion (TRAIL mediated apoptosis) of T regs (CD4 + CD25 + FoxP3 + CD39 + FR4 + GITR + CD127 - ), in blood, spleen, lymph node and tumor following the combined treatment. This led to the immune activation in the periphery, secondary lymphoid organs and massive infiltration of CD4 + , CD8 + and NK cells in the tumor, which correlated well with the complete response (cure; tumor free survival). Association of Treg depletion with the tumor response was further confirmed using low doses of cyclophosphamide (which depletes Tegs) and rapamycin (activator of Tregs),wherein the depletor of Tregs enhanced the efficacy of combined treatment, while Tregs enhancer compromised the efficacy. These studies unequivocally established the role of Tregs in determining the therapeutic response and can be used as a target for enhancing the efficacy of this combined treatment, besides establishing the potential of

  9. Enzymatic activity of Glucose Oxidase from Aspergillus niger IPBCC.08.610 On Modified Carbon Paste Electrode as Glucose Biosensor

    Science.gov (United States)

    Rohmayanti, T.; Ambarsari, L.; Maddu, A.

    2017-03-01

    Glucose oxidase (GOx) has been developed as glucose sensor for measuring blood glucose level because of its specificity to glucose oxidation. This research aimed to determine kinetic parameters of GOx activity voltametrically and further test its potential as a glucose biosensor. GOx, in this research, was produced by local fungi Aspergillus niger IPBCC.08.610 which was isolated from local vine in Tarakan, East Borneo, Indonesia. GOx was immobilized with glutaraldehyde, which cross-linked onto modified carbon paste electrode (MCPE) nanofiber polyaniline. Intracellular GOx activity was higher than extracellular ones. Immobilized GOx used glutaraldehyde 2.5% and dripped on the surface of MCPE nanofiber polyaniline. MCPE have a high conductance in copper with the diameter of 3 mm. The concentration of glucose in the lowest concentration of 0.2 mM generated a current value of 0.413 mA while 2 mM of glucose induced a current of 3,869 mA value. Km and Imax of GOx in MCPE activities polyaniline nanofiber were 2.88 mM and 3.869 mA,respectively, with turnover (Kcat) of 13 s-1. Sensitivity was 1.09 mA/mM and response time to produce a maximum peak current was 25 seconds. Km value was then converted into units of mg/dL and obtained 56.4 mg/dL. GOximmo-IPB|MCPE electrode is potential to be able to detect blood glucose level in a normal condition and hypoglycemia conditions

  10. Detection of high-sensitivity troponin in outpatients with stable pulmonary hypertension identifies a subgroup at higher risk of adverse outcomes.

    Science.gov (United States)

    Roy, Andrew K; McCullagh, Brian N; Segurado, Ricardo; McGorrian, Catherine; Keane, Elizabeth; Keaney, John; Fitzgibbon, Maria N; Mahon, Niall G; Murray, Patrick T; Gaine, Sean P

    2014-01-01

    The detection of elevations in cardiorenal biomarkers, such as troponins, B-type natriuretic peptides (BNPs), and neutrophil gelatinase-associated lipocalins, are associated with poor outcomes in patients hospitalized with acute heart failure. Less is known about the association of these markers with adverse events in chronic right ventricular dysfunction due to pulmonary hypertension, or whether their measurement may improve risk assessment in the outpatient setting. We performed a cohort study of 108 patients attending the National Pulmonary Hypertension Unit in Dublin, Ireland, from 2007 to 2009. Cox proportional hazards analysis and receiver operating characteristic curves were used to determine predictors of mortality and hospitalization. Death or hospitalization occurred in 50 patients (46.3%) during the median study period of 4.1 years. Independent predictors of mortality were: 1) decreasing 6-minute walk test (6MWT; hazard ratio [HR] 12.8; P < .001); 2) BNP (HR 6.68; P < .001); and 3) highly sensitive troponin (hsTnT; HR 5.48; P < .001). Adjusted hazard analyses remained significant when hsTnT was added to a model with BNP and 6MWT (HR 9.26, 95% CI 3.61-23.79), as did the predictive ability of the model for death and rehospitalization (area under the receiver operating characteristic curve 0.81, 95% CI 0.73-0.90). Detection of troponin using a highly sensitive assay identifies a pulmonary hypertension subgroup with a poorer prognosis. hsTnT may also be used in a risk prediction model to identify patients at higher risk who may require escalation of targeted pulmonary vasodilator therapies and closer clinical surveillance. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Higher magnesium intake is associated with lower fasting glucose and insulin, with no evidence of interaction with select genetic loci, in a meta-analysis of 15 charge consortium studies

    Science.gov (United States)

    Favorable associations between magnesium intake and glycemic traits, such as fasting glucose and insulin, are observed in observational and clinical studies, but whether genetic variation affects these associations is largely unknown. We hypothesized that single nucleotide polymorphisms (SNPs) assoc...

  12. Evidence for brain glucose dysregulation in Alzheimer's disease.

    Science.gov (United States)

    An, Yang; Varma, Vijay R; Varma, Sudhir; Casanova, Ramon; Dammer, Eric; Pletnikova, Olga; Chia, Chee W; Egan, Josephine M; Ferrucci, Luigi; Troncoso, Juan; Levey, Allan I; Lah, James; Seyfried, Nicholas T; Legido-Quigley, Cristina; O'Brien, Richard; Thambisetty, Madhav

    2018-03-01

    It is unclear whether abnormalities in brain glucose homeostasis are associated with Alzheimer's disease (AD) pathogenesis. Within the autopsy cohort of the Baltimore Longitudinal Study of Aging, we measured brain glucose concentration and assessed the ratios of the glycolytic amino acids, serine, glycine, and alanine to glucose. We also quantified protein levels of the neuronal (GLUT3) and astrocytic (GLUT1) glucose transporters. Finally, we assessed the relationships between plasma glucose measured before death and brain tissue glucose. Higher brain tissue glucose concentration, reduced glycolytic flux, and lower GLUT3 are related to severity of AD pathology and the expression of AD symptoms. Longitudinal increases in fasting plasma glucose levels are associated with higher brain tissue glucose concentrations. Impaired glucose metabolism due to reduced glycolytic flux may be intrinsic to AD pathogenesis. Abnormalities in brain glucose homeostasis may begin several years before the onset of clinical symptoms. Copyright © 2017 the Alzheimer's Association. All rights reserved.

  13. Association of Androgen Excess with Glucose Intolerance in Women with Polycystic Ovary Syndrome

    Science.gov (United States)

    Zhang, Bingjie; Wang, Jing; Shen, Shanmei; Liu, Jiayi; Sun, Jie; Ye, Xiao

    2018-01-01

    Women with polycystic ovary syndrome (PCOS) show high prevalence of glucose intolerance. This study aimed to investigate the association of androgen excess with glucose intolerance in PCOS. A total of 378 women with PCOS participated in the study. Free androgen index (FAI) was selected as indicator of hyperandrogenism. Insulin sensitivity was assessed by 1/homeostasis model assessment of insulin resistance (1/HOMA-IR) and Matsuda insulin sensitivity index (ISIM); β-cell function was assessed by disposition index (DI). We found that women with glucose intolerance had higher FAI levels compared to women with normal glucose tolerance (NGT) (prediabetes 6.2, T2DM 7.9 versus NGT 5.0, resp.; p intolerance (OR = 2.480, 95% CI 1.387–4.434), even after adjusting for age, BMI, waist circumference, hypertension, fasting insulin, testosterone, SHBG, and family history of diabetes. In addition, with FAI increase, glycosylated hemoglobin (HbA1c), plasma glucose concentrations, and serum insulin levels increased, while insulin sensitivity and β-cell function decreased. Our results suggested that androgen excess indicated by high FAI levels might serve as indicator of glucose intolerance, as it might promote insulin resistance and β-cell dysfunction in women with PCOS.

  14. The Opening of ATP-Sensitive K+ Channels Protects H9c2 Cardiac Cells Against the High Glucose-Induced Injury and Inflammation by Inhibiting the ROS-TLR4-Necroptosis Pathway

    Directory of Open Access Journals (Sweden)

    Weijie Liang

    2017-02-01

    Full Text Available Background/Aims: Hyperglycemia activates multiple signaling molecules, including reactive oxygen species (ROS, toll-like receptor 4 (TLR4, receptor-interacting protein 3 (RIP3, a kinase promoting necroptosis, which mediate hyperglycemia-induced cardiac injury. This study explored whether inhibition of ROS-TLR4-necroptosis pathway contributed to the protection of ATP-sensitive K+ (KATP channel opening against high glucose-induced cardiac injury and inflammation. Methods: H9c2 cardiac cells were treated with 35 mM glucose (HG to establish a model of HG-induced insults. The expression of RIP3 and TLR4 were tested by western blot. Generation of ROS, cell viability, mitochondrial membrane potential (MMP and secretion of inflammatory cytokines were measured as injury indexes. Results: HG increased the expression of TLR4 and RIP3. Necrostatin-1 (Nec-1, an inhibitor of necroptosis or TAK-242 (an inhibitor of TLR4 co-treatment attenuated HG-induced up-regulation of RIP3. Diazoxide (DZ, a mitochondrial KATP channel opener or pinacidil (Pin, a non-selective KATP channel opener or N-acetyl-L-cysteine (NAC, a ROS scavenger pre-treatment blocked the up-regulation of TLR4 and RIP3. Furthermore, pre-treatment with DZ or Pin or NAC, or co-treatment with TAK-242 or Nec-1 attenuated HG-induced a decrease in cell viability, and increases in ROS generation, MMP loss and inflammatory cytokines secretion. However, 5-hydroxy decanoic acid (5-HD, a mitochondrial KATP channel blocker or glibenclamide (Gli, a non-selective KATP channel blocker pre-treatment did not aggravate HG-induced injury and inflammation. Conclusion: KATP channel opening protects H9c2 cells against HG-induced injury and inflammation by inhibiting ROS-TLR4-necroptosis pathway.

  15. Analytical protocol for the sensitive determination of mannitol, sorbitol and glucose containing powders in pharmaceutical workplaces by ion chromatography using a pulsed amperometric detector.

    Science.gov (United States)

    Butler, Owen; Forder, James; Saunders, John

    2015-03-15

    Workers in the pharmaceutical industry can potentially be exposed to airborne dusts and powders that can contain potent active pharmaceutical ingredients (API). Occupational hygienists and health and safety professionals need to assess and ultimately minimise such inhalation and dermal exposure risks. Containment of dusts at source is the first line of defence but the performance of such technologies needs to be verified, for which purpose the good practice guide: assessing the particulate containment performance of pharmaceutical equipment, produced by the International Society for Pharmaceutical Engineering (ISPE), is a widely used reference document. This guide recommends the use of surrogate powders that can be used to challenge the performance of such containment systems. Materials such as lactose and mannitol are recommended as their physical properties (adhesion, compactability, dustiness, flow characteristics and particle sizes) mimic those of API-containing materials typically handled. Furthermore they are safe materials to use, are available in high purity and can be procured at a reasonable cost. The aim of this work was to develop and validate a sensitive ion-chromatography based analytical procedure for the determination of surrogate powders collected on filter samples so as to meet analytical requirements set out in this ISPE guide. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  16. The effects of carbon nanotube addition and oxyfluorination on the glucose-sensing capabilities of glucose oxidase-coated carbon fiber electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Im, Ji Sun; Yun, Jumi; Kim, Jong Gu [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Bae, Tae-Sung [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Korea Basic Science Institute (KBSI), Jeonju 561-756 (Korea, Republic of); Lee, Young-Seak, E-mail: youngslee@cnu.ac.kr [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2012-01-15

    Glucose-sensing electrodes were constructed from carbon fibers by electrospinning and heat treatment. By controlling the pore size, the specific surface area and pore volume of the electrospun carbon fibers were increased for efficient immobilization of the glucose oxidase. Carbon nanotubes were embedded as an electrically conductive additive to improve the electrical property of the porous carbon fibers. In addition, the surface of the porous carbon fibers was modified with hydrophilic functional groups by direct oxyfluorination to increase the affinity between the hydrophobic carbon surface and the hydrophilic glucose oxidase molecules. The porosity of the carbon fibers was improved significantly with approximately 28- and 35-fold increases in the specific surface area and pore volume, respectively. The number of chemical bonds between carbon and oxygen were increased with higher oxygen content during oxyfluorination based on the X-ray photoelectron spectroscopy results. Glucose sensing was carried out by current voltagram and amperometric methods. A high-performance glucose sensor was obtained with high sensitivity and rapid response time as a result of carbon nanotube addition, physical activation and surface modification. The mechanism of the highly sensitive prepared glucose sensor was modeled by an enzyme kinetics study using the Michaelis-Menten equation.

  17. Glucose improves object-location binding in visual-spatial working memory.

    Science.gov (United States)

    Stollery, Brian; Christian, Leonie

    2016-02-01

    There is evidence that glucose temporarily enhances cognition and that processes dependent on the hippocampus may be particularly sensitive. As the hippocampus plays a key role in binding processes, we examined the influence of glucose on memory for object-location bindings. This study aims to study how glucose modifies performance on an object-location memory task, a task that draws heavily on hippocampal function. Thirty-one participants received 30 g glucose or placebo in a single 1-h session. After seeing between 3 and 10 objects (words or shapes) at different locations in a 9 × 9 matrix, participants attempted to immediately reproduce the display on a blank 9 × 9 matrix. Blood glucose was measured before drink ingestion, mid-way through the session, and at the end of the session. Glucose significantly improves object-location binding (d = 1.08) and location memory (d = 0.83), but not object memory (d = 0.51). Increasing working memory load impairs object memory and object-location binding, and word-location binding is more successful than shape-location binding, but the glucose improvement is robust across all difficulty manipulations. Within the glucose group, higher levels of circulating glucose are correlated with better binding memory and remembering the locations of successfully recalled objects. The glucose improvements identified are consistent with a facilitative impact on hippocampal function. The findings are discussed in the context of the relationship between cognitive processes, hippocampal function, and the implications for glucose's mode of action.

  18. Pannexin-2-deficiency sensitizes pancreatic beta-cells to cytokine-induced apoptosis in vitro and impairs glucose tolerance in vivo

    DEFF Research Database (Denmark)

    Berchtold, Lukas A.; Miani, Michela; Diep, Thi A.

    2017-01-01

    -cells, and β-cell lines. The expression of Panx2, but not Panx1, was downregulated by interleukin-1β (IL-1β) plus interferon-γ (IFNγ), two pro-inflammatory cytokines suggested to contribute to β-cell demise in type 1 diabetes (T1D). siRNA-mediated knockdown (KD) of Panx2 aggravated cytokine-induced apoptosis...... in rat INS-1E cells and primary rat β-cells, suggesting anti-apoptotic properties of Panx2. An anti-apoptotic function of Panx2 was confirmed in isolated islets from Panx2-/- mice and in human EndoC-βH1 cells. Panx2 KD was associated with increased cytokine-induced activation of STAT3 and higher...

  19. Simulation and qualitative analysis of glucose variability, mean glucose, and hypoglycemia after subcutaneous insulin therapy for stress hyperglycemia.

    Science.gov (United States)

    Strilka, Richard J; Stull, Mamie C; Clemens, Michael S; McCaver, Stewart C; Armen, Scott B

    2016-01-27

    The critically ill can have persistent dysglycemia during the "subacute" recovery phase of their illness because of altered gene expression; it is also not uncommon for these patients to receive continuous enteral nutrition during this time. The optimal short-acting subcutaneous insulin therapy that should be used in this clinical scenario, however, is unknown. Our aim was to conduct a qualitative numerical study of the glucose-insulin dynamics within this patient population to answer the above question. This analysis may help clinicians design a relevant clinical trial. Eight virtual patients with stress hyperglycemia were simulated by means of a mathematical model. Each virtual patient had a different combination of insulin resistance and insulin deficiency that defined their unique stress hyperglycemia state; the rate of gluconeogenesis was also doubled. The patients received 25 injections of subcutaneous regular or Lispro insulin (0-6 U) with 3 rates of continuous nutrition. The main outcome measurements were the change in mean glucose concentration, the change in glucose variability, and hypoglycemic episodes. These end points were interpreted by how the ultradian oscillations of glucose concentration were affected by each insulin preparation. Subcutaneous regular insulin lowered both mean glucose concentrations and glucose variability in a linear fashion. No hypoglycemic episodes were noted. Although subcutaneous Lispro insulin lowered mean glucose concentrations, glucose variability increased in a nonlinear fashion. In patients with high insulin resistance and nutrition at goal, "rebound hyperglycemia" was noted after the insulin analog was rapidly metabolized. When the nutritional source was removed, hypoglycemia tended to occur at higher Lispro insulin doses. Finally, patients with severe insulin resistance seemed the most sensitive to insulin concentration changes. Subcutaneous regular insulin consistently lowered mean glucose concentrations and glucose

  20. [A non-invasive glucose measurement method based on orthogonal twin-polarized light and its pilot experimental investigation].

    Science.gov (United States)

    Wang, Hong; Wu, Baoming; Liu, Ding

    2010-04-01

    In order to overcome the existing shortcomings of the non-invasive blood glucose polarized light measurement methods of optical heterodyne detection and direct detection, we present in this paper a new orthogonal twin-polarized light (OTPL) non-invasive blood glucose measurement method, which converts the micro-angle rotated by an optical active substance such as glucose to the energy difference of OTPL, amplifies the signals by the high-sensitivity lock-in amplifier made of relevant principle, controls Faraday coil current to compensate the changes in deflection angle caused by blood glucose, and makes use of the linear relationship between blood glucose concentration and Faraday coil current to calculate blood glucose concentration. In our comparative experiment using the data measured by LX-20 automatic biochemical analyzer as a standard, a 0.9777 correlation coefficient is obtained in glucose concentration experiment, and a 0.952 in serum experiment. The result shows that this method has higher detection sensitivity and accuracy and lays a foundation for the development of practical new type of non-invasive blood glucose tester for diabetic patients.

  1. Electrochemical non-enzymatic glucose sensors

    International Nuclear Information System (INIS)

    Park, Sejin; Boo, Hankil; Chung, Taek Dong

    2006-01-01

    The electrochemical determination of glucose concentration without using enzyme is one of the dreams that many researchers have been trying to make come true. As new materials have been reported and more knowledge on detailed mechanism of glucose oxidation has been unveiled, the non-enzymatic glucose sensor keeps coming closer to practical applications. Recent reports strongly imply that this progress will be accelerated in 'nanoera'. This article reviews the history of unraveling the mechanism of direct electrochemical oxidation of glucose and making attempts to develop successful electrochemical glucose sensors. The electrochemical oxidation of glucose molecules involves complex processes of adsorption, electron transfer, and subsequent chemical rearrangement, which are combined with the surface reactions on the metal surfaces. The information about the direct oxidation of glucose on solid-state surfaces as well as new electrode materials will lead us to possible breakthroughs in designing the enzymeless glucose sensing devices that realize innovative and powerful detection. An example of those is to introduce nanoporous platinum as an electrode, on which glucose is oxidized electrochemically with remarkable sensitivity and selectivity. Better model of such glucose sensors is sought by summarizing and revisiting the previous reports on the electrochemistry of glucose itself and new electrode materials

  2. Impaired glucose tolerance in healthy men with low body weight

    Directory of Open Access Journals (Sweden)

    Schmoller André

    2011-02-01

    Full Text Available Abstract Background Impaired glucose tolerance (IGT and high body mass index (BMI are recognized risk factors for type 2 diabetes mellitus (T2DM. However, data suggest that also underweight predisposes people to develop T2DM. Here, we experimentally tested if already moderate underweight is associated with impaired glucose tolerance as compared to normal weight controls. Obese subjects were included as additional reference group. Method We included three groups of low weight, normal weight, and obese subjects comprising 15 healthy male participants each. All participants underwent a standardized hyperinsulinemic-euglycemic glucose clamp intervention to determine glucose tolerance. In addition, insulin sensitivity index (ISI was calculated by established equation. Results ISI values were higher in low and normal weight than in obese subjects (P P = 0.303. Comparable to obese participants (P = 0.178, glucose tolerance was found decreased in low weight as compared with normal weight subjects (P = 0.007. Pearson's correlation analysis revealed a positive relationship between glucose tolerance and BMI in low (P = 0.043 and normal weight subjects (P = 0.021, an effect that was found inverse in obese participants (P = 0.028. Conclusion Our study demonstrates that not only obese but also healthy people with moderate underweight display glucose intolerance. It is therefore suggested that all deviations from normal BMI may be accompanied by an increased risk of developing T2DM in later life indicating that the maintenance of body weight within the normal range has first priority in the prevention of this disease.

  3. Glucose Binding Protein as a Novel Optical Glucose Nanobiosensor

    Directory of Open Access Journals (Sweden)

    Majed DWEIK

    2009-11-01

    Full Text Available Development of an in vivo optical sensor requires the utilization of Near Infra Red (NIR fluorophores due to their ability to operate within the biological tissue window. Alexa Fluor 750 (AF750 and Alexa Fluor 680 (AF680 were examined as potential NIR fluorophores for an in vivo fluorescence resonance energy transfer (FRET glucose biosensor. AF680 and AF750 found to be a FRET pair and percent energy transfer was calculated. Next, the tested dye pair was utilized in a competitive binding assay in order to detect glucose. Concanavalin A (Con A and dextran have binding affinity, but in the presence of glucose, glucose displaces dextran due to its higher affinity to Con A than dextran. Finally, the percent signal transfer through porcine skin was examined. The results showed with approximately 4.0 mm porcine skin thickness, 1.98 % of the fluorescence was transmitted and captured by the detector.

  4. Glucose and cardiovascular risk

    NARCIS (Netherlands)

    Fuchs, M.; Hoekstra, J. B. L.; Mudde, A. H.

    2002-01-01

    The American Diabetes Association and the World Health Organisation have recently redefined the spectrum of abnormal glucose tolerance. The criteria for diabetes mellitus were sharpened and impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were classified as intermediate stages

  5. Resonator graphene microfluidic antenna (RGMA) for blood glucose detection

    Science.gov (United States)

    Jizat, Noorlindawaty Md.; Mohamad, Su Natasha; Ishak, Muhammad Ikman

    2017-09-01

    Graphene is capable of highly sensitive analyte detection due to its nanoscale nature. Here we show a resonator graphene microfluidic antenna (RGMA) is used to detect the dielectric properties of aqueous glucose solution which represent the glucose level in blood. Simulation verified the high sensitivity of proposed RGMA made with aqueous glucose solutions at different concentrations. The RGMA yielded a sensor sensitivity of 0.1882GHz/mgml-1 as plotted from the slope of the linear fit from the result averages in S11 and S21 parameter, respectively. This results indicate that the proposed resonator antenna achieves high sensitivity and linear to the changes of glucose concentration.

  6. The effect of 30 months of low-dose replacement therapy with recombinant human growth hormone (rhGH) on insulin and C-peptide kinetics, insulin secretion, insulin sensitivity, glucose effectiveness, and body composition in GH-deficient adults

    DEFF Research Database (Denmark)

    Rosenfalck, A M; Maghsoudi, S; Fisker, S

    2000-01-01

    The aim of the present study was to evaluate the long-term (30 months) metabolic effects of recombinant human GH (rhGH) given in a mean dose of 6.7 microg/kg x day (= 1.6 IU/day), in 11 patients with adult GH deficiency. Glucose metabolism was evaluated by an oral glucose tolerance test and an iv...... (frequently sampled iv glucose tolerance test) glucose tolerance test, and body composition was estimated by dual-energy x-ray absorptiometry. Treatment with rhGH induced persistent favorable changes in body composition, with a 10% increase in lean body mass (P ... in glucose tolerance, beta-cell response was still inappropriate. Our conclusion is that long-term rhGH-replacement therapy in GH deficiency adults induced a significant deterioration in glucose tolerance, profound changes in kinetics of C-peptide, and insulin and prehepatic insulin secretion, despite...

  7. Roles of the Gut in Glucose Homeostasis

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Gribble, Fiona; Horowitz, Michael

    2016-01-01

    The gastrointestinal tract plays a major role in the regulation of postprandial glucose profiles. Gastric emptying is a highly regulated process, which normally ensures a limited and fairly constant delivery of nutrients and glucose to the proximal gut. The subsequent digestion and absorption...... of nutrients are associated with the release of a set of hormones that feeds back to regulate subsequent gastric emptying and regulates the release of insulin, resulting in downregulation of hepatic glucose production and deposition of glucose in insulin-sensitive tissues. These remarkable mechanisms normally...... keep postprandial glucose excursions low, regardless of the load of glucose ingested. When the regulation of emptying is perturbed (e.g., pyloroplasty, gastric sleeve or gastric bypass operation), postprandial glycemia may reach high levels, sometimes followed by profound hypoglycemia. This article...

  8. Hypothalamic glucose sensing: making ends meet

    Directory of Open Access Journals (Sweden)

    Vanessa eRouth

    2014-12-01

    Full Text Available The neuroendocrine system governs essential survival and homeostatic functions. For example, growth is needed for development. Thermoregulation maintains optimal core temperature in a changing environment. Reproduction ensures species survival. Stress and immune responses enable an organism to overcome external and internal threats. The circadian system regulates arousal and sleep such that vegetative and active functions do not overlap. All of these functions require a significant portion of the body’s energy. As the integrator of the neuroendocrine system, the hypothalamus carefully assesses the energy status of the body in order to appropriately partition resources to provide for each system without compromising the others. While doing so the hypothalamus must ensure that adequate glucose levels are preserved for brain function since glucose is the primary fuel of the brain. To this end, the hypothalamus contains specialized glucose sensing neurons which are scattered throughout the nuclei controlling distinct neuroendocrine functions. We hypothesize that these neurons play a key role in enabling the hypothalamus to partition energy to meet these peripheral survival needs without endangering the brain’s glucose supply. The goal of this review is to describe the varied mechanisms underlying glucose sensing in neurons within discrete hypothalamic nuclei. We will then evaluate the way in which peripheral energy status regulates glucose sensitivity. For example, during energy deficit such as fasting specific hypothalamic glucose sensing neurons become sensitized to decreased glucose. This increases the gain of the information relay when glucose availability is a greater concern for the brain. Finally, changes in glucose sensitivity under pathological conditions (e.g., recurrent insulin-hypoglycemia, diabetes will be addressed. The overall goal of this review is to place glucose sensing neurons within the context of hypothalamic control of

  9. Design of FitFor2 study: the effects of an exercise program on insulin sensitivity and plasma glucose levels in pregnant women at high risk for gestational diabetes

    Directory of Open Access Journals (Sweden)

    Eekhoff Elisabeth MW

    2009-01-01

    Full Text Available Abstract Background Pregnancy is a period in the life of women that is often associated with decreased daily physical activity and/or exercise. However, maintaining adequate levels of daily physical activity during pregnancy is important for mother and child. Studies suggest that moderate daily physical activity and exercise during pregnancy are associated with reductions in the risk of gestational diabetes mellitus (GDM. However, at present, physical activity is not routinely advised to pregnant women at risk for gestational diabetes in the Netherlands. In FitFor2-study we aim to assess whether an exercise program can improve insulin sensitivity and fasting plasma glucose levels of women at high risk for gestational diabetes, assuming that this will lower their risk of gestational diabetes. Methods The FitFor2-study is a randomised controlled trial. Women who visit one of the participating hospitals or midwifery practices and who are at risk for gestational diabetes are eligible to participate. After baseline measurement they are randomly allocated to in the intervention or control group. The intervention group receives an exercise program twice a week in addition to usual care. The exercise program consist of aerobic and strength exercises and takes place under close supervision of a physiotherapist. Data are collected at 15, 24 and 32 weeks of pregnancy and 12 weeks after delivery. Primary maternal outcome measures are fasting plasma glucose and relative increase in insulin resistance. Primary neonatal outcome is birth weight. Secondary outcome measures are: maternal serum triglycerides, HDL, cholesterol, HbA1c, maternal weight gain during pregnancy, maternal physical activity level, foetal growth. Discussion If the FitFor2 intervention program proves to be effective, obstetricians and midwives should refer women at risk for GDM to a special exercise program. Exercise programs for pregnant women under supervision of an experienced trainer are

  10. Effect of ground cinnamon on postprandial blood glucose concentration in normal-weight and obese adults.

    Science.gov (United States)

    Magistrelli, Ashley; Chezem, Jo Carol

    2012-11-01

    In healthy normal-weight adults, cinnamon reduces blood glucose concentration and enhances insulin sensitivity. Insulin resistance, resulting in increased fasting and postprandial blood glucose and insulin levels, is commonly observed in obese individuals. The objective of the study was to compare declines in postprandial glycemic response in normal-weight and obese subjects with ingestion of 6 g ground cinnamon. In a crossover study, subjects consumed 50 g available carbohydrate in instant farina cereal, served plain or with 6 g ground cinnamon. Blood glucose concentration, the main outcome measure, was assessed at minutes 0, 15, 30, 45, 60, 90, and 120. Repeated-measures analysis of variance evaluated the effects of body mass index (BMI) group, dietary condition, and time on blood glucose. Paired t-test assessed blood glucose at individual time points and glucose area under the curve (AUC) between dietary conditions. Thirty subjects between the ages of 18 and 30 years, 15 with BMIs between 18.5 and 24.9 and 15 with BMIs of 30.0 or more, completed the study. There was no significant difference in blood glucose between the two BMI groups at any time point. However, in a combined analysis of all subjects, the addition of cinnamon to the cereal significantly reduced 120-minute glucose AUC (P=0.008) and blood glucose at 15 (P=0.001), 30 (Pblood glucose was significantly higher with cinnamon consumption (Pglucose response in normal weight and obese adults. Copyright © 2012 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  11. Ventromedial hypothalamic glucose sensing and glucose homeostasis vary throughout the estrous cycle.

    Science.gov (United States)

    Santiago, Ammy M; Clegg, Deborah J; Routh, Vanessa H

    2016-12-01

    17β-Estradiol (17βE) regulates glucose homeostasis in part by centrally mediated mechanisms. In female rodents, the influence of the ovarian cycle on hypoglycemia counterregulation and glucose tolerance is unclear. We found previously that in prepubertal females, 17βE modulates glucose sensing in nonadapting glucose-inhibited (GI) and adapting GI (AdGI) neurons within the ventrolateral portion of the ventromedial nucleus (VL-VMN). Nonadapting GI neurons persistently decrease their activity as glucose increases while AdGI neurons transiently respond to a glucose increase. To begin to understand if endogenous fluctuations in estrogen levels across the estrous cycle impact hypothalamic glucose sensing and glucose homeostasis, we assessed whether hypoglycemia counterregulation and glucose tolerance differed across the phases of the estrous cycle. We hypothesized that the response to insulin-induced hypoglycemia (IIH) and/or glucose tolerance would vary throughout the estrous cycle according to changes in 17βE availability. Moreover, that these changes would correlate with estrous-dependent changes in the glucose sensitivity of VL-VMN glucose-sensing neurons (GSNs). These hypotheses were tested in female mice by measuring the response to IIH, glucose tolerance and the glucose sensitivity of VL-VMN GSNs during each phase of the estrous cycle. Furthermore, a physiological brain concentration of 17βE seen during proestrus was acutely applied to brain slices isolated on the day of diestrous and the response to low glucose in VL-VMN GSNs was assayed. The response to IIH was strongest during diestrous. The response of nonadapting GI and AdGI neurons to a glucose decrease from 2.5 to 0.5mM also peaked during diestrous; an effect which was blunted by the addition of 17βE. In contrast, the glucose sensitivity of the subpopulation of GSNs which are excited by glucose (GE) was not affected by estrous phase or exogenous 17βE application. These data suggest that physiological

  12. Ventromedial hypothalamic glucose sensing and glucose homeostasis vary throughout the estrous cycle

    Science.gov (United States)

    Santiago, Ammy M.; Clegg, Deborah J.; Routh, Vanessa H.

    2016-01-01

    Objective 17β-Estradiol (17βE) regulates glucose homeostasis in part by centrally mediated mechanisms. In female rodents, the influence of the ovarian cycle on hypoglycemia counterregulation and glucose tolerance is unclear. We found previously that in prepubertal females, 17βE modulates glucose sensing in nonadapting glucose-inhibited (GI) and adapting GI (AdGI) neurons within the ventrolateral portion of the ventromedial nucleus (VL-VMN). Nonadapting GI neurons persistently decrease their activity as glucose increases while AdGI neurons transiently respond to a glucose increase. To begin to understand if endogenous fluctuations in estrogen levels across the estrous cycle impact hypothalamic glucose sensing and glucose homeostasis, we assessed whether hypoglycemia counterregulation and glucose tolerance differed across the phases of the estrous cycle. We hypothesized that the response to insulin-induced hypoglycemia (IIH) and/or glucose tolerance would vary throughout the estrous cycle according to changes in 17βE availability. Moreover, that these changes would correlate with estrous-dependent changes in the glucose sensitivity of VL-VMN glucose-sensing neurons (GSNs). Methods These hypotheses were tested in female mice by measuring the response to IIH, glucose tolerance and the glucose sensitivity of VL-VMN GSNs during each phase of the estrous cycle. Furthermore, a physiological brain concentration of 17βE seen during proestrus was acutely applied to brain slices isolated on the day of diestrous and the response to low glucose in VL-VMN GSNs was assayed. Results The response to IIH was strongest during diestrous. The response of nonadapting GI and AdGI neurons to a glucose decrease from 2.5 to 0.5mM also peaked during diestrous; an effect which was blunted by the addition of 17βE. In contrast, the glucose sensitivity of the subpopulation of GSNs which are excited by glucose (GE) was not affected by estrous phase or exogenous 17βE application. Conclusion

  13. Validity of a portable glucose, total cholesterol, and triglycerides multi-analyzer in adults.

    Science.gov (United States)

    Coqueiro, Raildo da Silva; Santos, Mateus Carmo; Neto, João de Souza Leal; Queiroz, Bruno Morbeck de; Brügger, Nelson Augusto Jardim; Barbosa, Aline Rodrigues

    2014-07-01

    This study investigated the accuracy and precision of the Accutrend Plus system to determine blood glucose, total cholesterol, and plasma triglycerides in adults and evaluated its efficiency in measuring these blood variables. The sample consisted of 53 subjects (≥ 18 years). For blood variable laboratory determination, venous blood samples were collected and processed in a Labmax 240 analyzer. To measure blood variables with the Accutrend Plus system, samples of capillary blood were collected. In the analysis, the following tests were included: Wilcoxon and Student's t-tests for paired samples, Lin's concordance coefficient, Bland-Altman method, receiver operating characteristic curve, McNemar test, and k statistics. The results show that the Accutrend Plus system provided significantly higher values (p ≤ .05) of glucose and triglycerides but not of total cholesterol (p > .05) as compared to the values determined in the laboratory. However, the system showed good reproducibility (Lin's coefficient: glucose = .958, triglycerides = .992, total cholesterol = .940) and high concordance with the laboratory method (Lin's coefficient: glucose = .952, triglycerides = .990, total cholesterol = .944) and high sensitivity (glucose = 80.0%, triglycerides = 90.5%, total cholesterol = 84.4%) and specificity (glucose = 100.0%, triglycerides = 96.9%, total cholesterol = 95.2%) in the discrimination of high values of the three blood variables analyzed. It could be concluded that despite the tendency to overestimate glucose and triglyceride levels, a portable multi-analyzer is a valid alternative for the monitoring of metabolic disorders and cardiovascular risk factors. © The Author(s) 2013.

  14. Hollow optical-fiber based infrared spectroscopy for measurement of blood glucose level by using multi-reflection prism.

    Science.gov (United States)

    Kino, Saiko; Omori, Suguru; Katagiri, Takashi; Matsuura, Yuji

    2016-02-01

    A mid-infrared attenuated total reflection (ATR) spectroscopy system employing hollow optical fibers and a trapezoidal multi-reflection ATR prism has been developed to measure blood glucose levels. Using a multi-reflection prism brought about higher sensitivity, and the flat and wide contact surface of the prism resulted in higher measurement reproducibility. An analysis of in vivo measurements of human inner lip mucosa revealed clear signatures of glucose in the difference spectra between ones taken during the fasting state and ones taken after ingestion of glucose solutions. A calibration plot based on the absorption peak at 1155 cm(-1) that originates from the pyranose ring structure of glucose gave measurement errors less than 20%.

  15. Effect of degree of lipomobilization on results of glucose test in dairy cows in heat stress

    Directory of Open Access Journals (Sweden)

    Cincović M.R.

    2012-01-01

    Full Text Available Cows exposed to heat stress exhibit a decreased ability to mobilize lipids due to increased sensitivity to insulin, which is expressed in a decreased concentration of NEFA. However, certain cows can preserve the level of lipid mobilization after adapting to heat stress. We assumed that cows that have a preserved ability to mobilize lipids are less sensitive to insulin and that they have a lower tolerance for glucose. The aim of this work was to compare the results of an intravenous glucose tolerance test in cows that exhibited, in prolonged heat stress, a decreased (NEFA0.30 mmol/l ability for lipid mobilization. Glucose concentration and NEFA concentration were measured following intravenous application of glucose. The mean glycaemic index value did not differ statistically significantly between the two groups of cows at 10, 15 and 20 minutes after glucose application (p>0.05, but there was a tendency at 10 and 15 minutes for the glycaemia to be higher in cows with preserved lipomobilization (p<0.1. At 30, 60 and 90 minutes after glucose application, glycaemia was statistically significantly higher (p<0.01; p<0.05 and p<0.05 in the group of cows with preserved lipomobilization. The glycaemic index values (mmol/l shown in the same order (30, 60 and 90 minutes were as follows 9.91±0.21: 9.23±0.41; 5.41±0.5: 4.67±0.33 and 4.31±0.39: 3.47±0.37. The mean value for NEFA concentration in samples originating from the two experimental groups of cows did not differ statistically significantly following glucose application. The NEFA concentration showed a tendency to be higher in cows with preserved lipid mobilization in comparison with cows with decreased lipomobilization at 20 and 30 minutes after glucose application (p<0.1. Following the intravenous glucose tolerance test, NEFA and glucose concentrations were in a significant negative correlation, and that correlation was more expressed in cows with decreased lipomobilization. Cows with preserved

  16. Postprandial glucose response to selected tropical fruits in normal glucose-tolerant Nigerians.

    Science.gov (United States)

    Edo, A; Eregie, A; Adediran, O; Ohwovoriole, A; Ebengho, S

    2011-01-01

    The glycemic response to commonly eaten fruits in Nigeria has not been reported. Therefore, this study assessed the plasma glucose response to selected fruits in Nigeria. Ten normal glucose-tolerant subjects randomly consumed 50 g carbohydrate portions of three fruits: banana (Musa paradisiaca), pineapple (Ananus comosus), and pawpaw (Carica papaya), and a 50-g glucose load at 1-week intervals. Blood samples were collected in the fasting state and half-hourly over a 2-h period post-ingestion of the fruits or glucose. The samples were analyzed for plasma glucose concentrations. Plasma glucose responses were assessed by the peak plasma glucose concentration, maximum increase in plasma glucose, 2-h postprandial plasma glucose level, and incremental area under the glucose curve and glycemic index (GI). The results showed that the blood glucose response to these three fruits was similar in terms of their incremental areas under the glucose curve, maximum increase in plasma glucose, and glycemic indices (GIs). The 2-h postprandial plasma glucose level of banana was significantly higher than that of pineapple, P < 0.025. The mean ± SEM GI values were as follows: pawpaw; 86 ± 26.8%; banana, 75.1 ± 21.8%; pineapple, 64.5 ± 11.3%. The GI of glucose is taken as 100. The GI of pineapple was significantly lower than that of glucose (P < 0.05). Banana, pawpaw, and pineapple produced a similar postprandial glucose response. Measured portions of these fruits may be used as fruit exchanges with pineapple having the most favorable glycemic response.

  17. Design of Cyclic Peptide Based Glucose Receptors and Their Application in Glucose Sensing.

    Science.gov (United States)

    Li, Chao; Chen, Xin; Zhang, Fuyuan; He, Xingxing; Fang, Guozhen; Liu, Jifeng; Wang, Shuo

    2017-10-03

    Glucose assay is of great scientific significance in clinical diagnostics and bioprocess monitoring, and to design a new glucose receptor is necessary for the development of more sensitive, selective, and robust glucose detection techniques. Herein, a series of cyclic peptide (CP) glucose receptors were designed to mimic the binding sites of glucose binding protein (GBP), and CPs' sequence contained amino acid sites Asp, Asn, His, Asp, and Arg, which constituted the first layer interactions of GBP. The properties of these CPs used as a glucose receptor or substitute for the GBP were studied by using a quartz crystal microbalance (QCM) technique. It was found that CPs can form a self-assembled monolayer at the Au quartz electrode surface, and the monolayer's properties were characterized by using cyclic voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. The CPs' binding affinity to saccharide (i.e., galactose, fructose, lactose, sucrose, and maltose) was investigated, and the CPs' sensitivity and selectivity toward glucose were found to be dependent upon the configuration,i.e., the amino acids sequence of the CPs. The cyclic unit with a cyclo[-CNDNHCRDNDC-] sequence gave the highest selectivity and sensitivity for glucose sensing. This work suggests that a synthetic peptide bearing a particular functional sequence could be applied for developing a new generation of glucose receptors and would find huge application in biological, life science, and clinical diagnostics fields.

  18. Glucose and memory: the influence of drink, expectancy, and beliefs.

    Science.gov (United States)

    Stollery, Brian; Christian, Leonie

    2013-08-01

    An increasing number of studies suggest that glucose can enhance aspects of memory and the central methodology is the use of the glucose-placebo design. One critical issue therefore is separating the pharmacological effects of glucose from the expectancies created by consuming a drink that might contain glucose. A modified balanced placebo design examined the role that expectancy and belief about the drink consumed has on the pharmacological changes observed following glucose consumption. Ninety-three participants, allocated according to a drink (glucose, placebo) × message (told glucose, told nothing, told placebo) unrelated design, were administered tasks assessing immediate and delayed verbal free recall, spatial recognition and semantic verification. Each task has some evidence for hippocampus involvement, and variations in task difficulty were used to assess the idea that glucose effects are sensitive to task difficulty. While the messages biased drink judgements in the expected direction, judgements of drink content were at chance and glucose only enhanced delayed free recall. The subtle effects of the messages did not modify the glucose enhancement. However, believing glucose had been consumed showed an independent improvement in delayed free recall. There was no evidence that task complexity enhanced the glucose effect. The findings indicate that expectancy effects are unlikely to be confused with glucose enhancements, but beliefs about consuming glucose can augment performance on delayed free recall. The discussion considers the hippocampus and complexity hypotheses of glucose's mode of action and proposes the routine collection of drink beliefs in future studies.

  19. Stimulation of the endogenous incretin glucose-dependent insulinotropic peptide by enteral dextrose improves glucose homeostasis and inflammation in murine endotoxemia.

    Science.gov (United States)

    Shah, Faraaz Ali; Singamsetty, Srikanth; Guo, Lanping; Chuan, Byron W; McDonald, Sherie; Cooper, Bryce A; O'Donnell, Brett J; Stefanovski, Darko; Wice, Burton; Zhang, Yingze; O'Donnell, Christopher P; McVerry, Bryan J

    2018-03-01

    Loss of glucose homeostasis during sepsis is associated with increased organ dysfunction and higher mortality. Novel therapeutic strategies to promote euglycemia in sepsis are needed. We have previously shown that early low-level intravenous (IV) dextrose suppresses pancreatic insulin secretion and induces insulin resistance in septic mice, resulting in profound hyperglycemia and worsened systemic inflammation. In this study, we hypothesized that administration of low-level dextrose via the enteral route would stimulate intestinal incretin hormone production, potentiate insulin secretion in a glucose-dependent manner, and thereby improve glycemic control in the acute phase of sepsis. We administered IV or enteral dextrose to 10-week-old male C57BL/6J mice exposed to bacterial endotoxin and measured incretin hormone release, glucose disposal, and proinflammatory cytokine production. Compared with IV administration, enteral dextrose increased circulating levels of the incretin hormone glucose-dependent insulinotropic peptide (GIP) associated with increased insulin release and insulin sensitivity, improved mean arterial pressure, and decreased proinflammatory cytokines in endotoxemic mice. Exogenous GIP rescued glucose metabolism, improved blood pressure, and increased insulin release in endotoxemic mice receiving IV dextrose, whereas pharmacologic inhibition of GIP signaling abrogated the beneficial effects of enteral dextrose. Thus, stimulation of endogenous GIP secretion by early enteral dextrose maintains glucose homeostasis and attenuates the systemic inflammatory response in endotoxemic mice and may provide a therapeutic target for improving glycemic control and clinical outcomes in patients with sepsis. Published by Elsevier Inc.

  20. Extraction and Refinement Strategy for Detection of Autism in 18-Month-Olds: A Guarantee of Higher Sensitivity and Specificity in the Process of Mass Screening

    Science.gov (United States)

    Honda, Hideo; Shimizu, Yasuo; Nitto, Yukari; Imai, Miho; Ozawa, Takeshi; Iwasa, Mitsuaki; Shiga, Keiko; Hira, Tomoko

    2009-01-01

    Background: For early detection of autism, it is difficult to maintain an efficient level of sensitivity and specificity based on observational data from a single screening. The Extraction and Refinement (E&R) Strategy utilizes a public children's health surveillance program to produce maximum efficacy in early detection of autism. In the…

  1. Correlation between blood glucose levels and salivary glucose levels with oral ulcer in diabetic patients

    Directory of Open Access Journals (Sweden)

    Fildzah Rahman

    2016-06-01

    Full Text Available Diabetes Mellitus (DM is a syndrome in metabolism of carbohydrates which indicated by the increased level of blood glucose and also may increase salivary glucose levels. Oral ulcer has been frequently recognized in diabetic patients, which can be due to increased glucose in oral fluids and immune dysfunction. This study aimed to determine the correlation of blood glucose levels and salivary glucose levels with oral ulcer in diabetic patients. Analytic observational study was carried out through the determination of blood glucose levels just by way of strip using a glucometer and salivary glucose levels with the method "GOD-PAP test enzymatic colorimetric". Oral ulcer was determined in presenting ulcer on 30 patients with DM. The results showed r = 0.228, which is higher salivary glucose levels followed by high levels of blood glucose, and intraoral examination of oral ulcer found in the whole sample and the most location commonly found in buccal mucosa and lingual. It was concluded that there is a correlation between blood glucose levels and salivary glucose levels, and glucose levels affect the occurrence of oral ulcer in patients with DM

  2. Differences in cardiovascular risk profile based on relationship between post-load plasma glucose and fasting plasma levels.

    Science.gov (United States)

    Succurro, Elena; Marini, Maria Adelaide; Grembiale, Alessandro; Lugarà, Marina; Andreozzi, Francesco; Sciacqua, Angela; Hribal, Marta Letizia; Lauro, Renato; Perticone, Francesco; Sesti, Giorgio

    2009-05-01

    It has been shown that subjects with normal glucose tolerance (NGT), whose plasma glucose (PG) levels do not return to their fasting PG level within 2 h during an oral glucose tolerance test (OGTT) (Group I), have a significantly higher risk to develop type 2 diabetes than NGT subjects whose 2-h glucose returns to, or drops below, the fasting level (Group I). However, it is still unsettled whether individuals in Group II have a more atherogenic profile than Group I subjects. To address this issue, we examined 266 non-diabetic offspring of type 2 diabetic patients, recruited in the context of EUGENE2 cross-sectional study. All subjects underwent an euglycaemic-hyperinsulinemic clamp to assess glucose tolerance and insulin sensitivity. Furthermore, cardiovascular risk factors and ultrasound measurement of carotid intima-media thickness (IMT) were evaluated. Individuals in Group II exhibited significantly higher waist circumference, blood pressure, triglycerides, 2-h post-load PG, hsC-reactive protein, interleukin-6, insulin-like growth factor-1 (IGF-1), IMT, and lower insulin sensitivity than subjects in Group I. Subjects with NGT, whose PG concentration does not return to their fasting PG level within 2 h during OGTT, have an atherogenic profile, suggesting that performing OGTT with measurement of PG every 30 min may be useful to assess the risk for cardiovascular disease in glucose-tolerant subjects.

  3. Effort-reward-imbalance in healthy teachers is associated with higher LPS-stimulated production and lower glucocorticoid sensitivity of interleukin-6 in vitro.

    Science.gov (United States)

    Bellingrath, Silja; Rohleder, Nicolas; Kudielka, Brigitte M

    2013-02-01

    According to the effort-reward-imbalance (ERI) model, a lack of reciprocity between costs and gains at work increases the risk for adverse health outcomes. Inflammation has been shown to play a crucial role in a variety of stress-related diseases and alterations in immune system glucocorticoid sensitivity may help to explain the increased risk for cardiovascular disease (CVD) and depression related to chronic work stress. Changes in lipopolysaccharide (LPS)-induced interleukin (IL)-6 production and inhibition of IL-6 production by dexamethasone in reaction to the Trier Social Stress Test (TSST) were assessed in forty-six healthy school teachers to test whether chronic work stress is accompanied by alterations in inflammatory activity and glucocorticoid sensitivity of the innate immune system. High ERI was associated with an increase in pro-inflammatory potential, reflected in elevated IL-6 production before and after stress and with a lower capacity of dexamethasone to suppress IL-6 production in vitro over all measurement time points. ERI was not associated with stress-related changes in GC sensitivity. The present findings suggest a less effective anti-inflammatory regulation by glucocorticoids in teachers suffering from chronic work stress. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Amperometric glucose biosensor based on glucose oxidase dispersed in multiwalled carbon nanotubes/graphene oxide hybrid biocomposite.

    Science.gov (United States)

    Palanisamy, Selvakumar; Cheemalapati, Srikanth; Chen, Shen-Ming

    2014-01-01

    An amperometric glucose biosensor based on enhanced and fast direct electron transfer (DET) of glucose oxidase (GOx) at enzyme dispersed multiwalled carbon nanotubes/graphene oxide (MWCNT/GO) hybrid biocomposite was developed. The fabricated hybrid biocomposite was characterized by transmission electron microscopy (TEM), Raman and infrared spectroscopy (IR). The TEM image of hybrid biocomposite reveals that a thin layer of GOx was covered on the surface of MWCNT/GO hybrid composite. IR results validate that the hybrid biocomposite was formed through the electrostatic interactions between GOx and MWCNT/GO hybrid composite. Further, MWCNT/GO hybrid composite has also been characterized by TEM and UV-visible spectroscopy. A pair of well-defined redox peak was observed for GOx immobilized at the hybrid biocomposite electrode than that immobilized at the MWCNT modified electrode. The electron transfer rate constant (Ks) of GOx at the hybrid biocomposite was calculated to be 11.22s(-1). The higher Ks value revealed that fast DET of GOx occurred at the electrode surface. Moreover, fabricated biosensor showed a good sensitivity towards glucose oxidation over a linear range 0.05-23.2mM. The limit of detection (LOD) was estimated to be 28μM. The good features of the proposed biosensor could be used for the accurate detection of glucose in the biological samples. © 2013.

  5. Glycosylation site-targeted PEGylation of glucose oxidase retains native enzymatic activity.

    Science.gov (United States)

    Ritter, Dustin W; Roberts, Jason R; McShane, Michael J

    2013-04-10

    Targeted PEGylation of glucose oxidase at its glycosylation sites was investigated to determine the effect on enzymatic activity, as well as the bioconjugate's potential in an optical biosensing assay. Methoxy-poly(ethylene glycol)-hydrazide (4.5kDa) was covalently coupled to periodate-oxidized glycosylation sites of glucose oxidase from Aspergillus niger. The bioconjugate was characterized using gel electrophoresis, liquid chromatography, mass spectrometry, and dynamic light scattering. Gel electrophoresis data showed that the PEGylation protocol resulted in a drastic increase (ca. 100kDa) in the apparent molecular mass of the protein subunit, with complete conversion to the bioconjugate; liquid chromatography data corroborated this large increase in molecular size. Mass spectrometry data proved that the extent of PEGylation was six poly(ethylene glycol) chains per glucose oxidase dimer. Dynamic light scattering data indicated the absence of higher-order oligomers in the PEGylated GOx sample. To assess stability, enzymatic activity assays were performed in triplicate at multiple time points over the course of 29 days in the absence of glucose, as well as before and after exposure to 5% w/v glucose for 24h. At a confidence level of 95%, the bioconjugate's performance was statistically equivalent to native glucose oxidase in terms of activity retention over the 29 day time period, as well as following the 24h glucose exposure. Finally, the bioconjugate was entrapped within a poly(2-hydroxyethyl methacrylate) hydrogel containing an oxygen-sensitive phosphor, and the construct was shown to respond approximately linearly with a 220±73% signal change (n=4, 95% confidence interval) over the physiologically-relevant glucose range (i.e., 0-400mg/dL); to our knowledge, this represents the first demonstration of PEGylated glucose oxidase incorporated into an optical biosensing assay. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Glucose transport in brain - effect of inflammation.

    Science.gov (United States)

    Jurcovicova, J

    2014-01-01

    Glucose is transported across the cell membrane by specific saturable transport system, which includes two types of glucose transporters: 1) sodium dependent glucose transporters (SGLTs) which transport glucose against its concentration gradient and 2) sodium independent glucose transporters (GLUTs), which transport glucose by facilitative diffusion in its concentration gradient. In the brain, both types of transporters are present with different function, affinity, capacity, and tissue distribution. GLUT1 occurs in brain in two isoforms. The more glycosylated GLUT1 is produced in brain microvasculature and ensures glucose transport across the blood brain barrier (BBB). The less glycosylated form is localized in astrocytic end-feet and cell bodies and is not present in axons, neuronal synapses or microglia. Glucose transported to astrocytes by GLUT1 is metabolized to lactate serving to neurons as energy source. Proinflammatory cytokine interleukin (IL)-1β upregulates GLUT1 in endothelial cells and astrocytes, whereas it induces neuronal death in neuronal cell culture. GLUT2 is present in hypothalamic neurons and serves as a glucose sensor in regulation of food intake. In neurons of the hippocampus, GLUT2 is supposed to regulate synaptic activity and neurotransmitter release. GLUT3 is the most abundant glucose transporter in the brain having five times higher transport capacity than GLUT1. It is present in neuropil, mostly in axons and dendrites. Its density and distribution correlate well with the local cerebral glucose demands. GLUT5 is predominantly fructose transporter. In brain, GLUT5 is the only hexose transporter in microglia, whose regulation is not yet clear. It is not present in neurons. GLUT4 and GLUT8 are insulin-regulated glucose transporters in neuronal cell bodies in the cortex and cerebellum, but mainly in the hippocampus and amygdala, where they maintain hippocampus-dependent cognitive functions. Insulin translocates GLUT4 from cytosol to plasma

  7. Glucokinase, the pancreatic glucose sensor, is not the gut glucose sensor

    DEFF Research Database (Denmark)

    Murphy, R; Tura, A; Clark, P M

    2008-01-01

    AIMS/HYPOTHESIS: The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotrophic peptide (GIP) are released from intestinal endocrine cells in response to luminal glucose. Glucokinase is present in these cells and has been proposed as a glucose sensor. The physiological...... role of glucokinase can be tested using individuals with heterozygous glucokinase gene (GCK) mutations. If glucokinase is the gut glucose sensor, GLP-1 and GIP secretion during a 75 g OGTT would be lower in GCK mutation carriers compared with controls. METHODS: We compared GLP-1 and GIP concentrations...... measured at five time-points during a 75 g OGTT in 49 participants having GCK mutations with those of 28 familial controls. Mathematical modelling of glucose, insulin and C-peptide was used to estimate basal insulin secretion rate (BSR), total insulin secretion (TIS), beta cell glucose sensitivity...

  8. Pathophysiological Characteristics Underlying Different Glucose Response Curves

    DEFF Research Database (Denmark)

    Hulman, Adam; Witte, Daniel R; Vistisen, Dorte

    2018-01-01

    different glucose curve patterns and studied their stability and reproducibility over 3 years of follow-up. RESEARCH DESIGN AND METHODS: We analyzed data from participants without diabetes from the observational cohort from the European Group for the Study of Insulin Resistance: Relationship between Insulin...... and secretion. The glucose patterns identified at follow-up were similar to those at baseline, suggesting that the latent class method is robust. We integrated our classification model into an easy-to-use online application that facilitates the assessment of glucose curve patterns for other studies. CONCLUSIONS...... Sensitivity and Cardiovascular Disease study; participants had a five-time point OGTT at baseline (n = 1,443) and after 3 years (n = 1,045). Measures of insulin sensitivity and secretion were assessed at baseline with a euglycemic-hyperinsulinemic clamp and intravenous glucose tolerance test. Heterogeneous...

  9. [Thromboresistance of glucose-containing hydrogels].

    Science.gov (United States)

    Valuev, I L; Valuev, L I; Vanchugova, L V; Obydennova, I V; Valueva, T A

    2013-01-01

    The thromboresistance of glucose-sensitive polymer hydrogels, modeling one of the functions of the pancreas, namely, the ability to secrete insulin in response to the introduction of glucose into the environment, has been studied. Hydrogels were synthesized by the copolymerization of hydroxyethyl methacrylate with N-acryloyl glucosamine in the presence of a cross-linking agent and subsequently treated with concanavalin A. Introduction of glucose residues into the hydrogel did not result in significant changes in either the number of trombocytes adhered to the hydrogel or the degree of denaturation of blood plasma proteins interacting with the hydrogel. Consequently, the biological activity of insulin did not change after release from the hydrogel. The use of glucose-sensitive hydrogels is supposed to contribute to the development of a novel strategy for the treatment of diabetes.

  10. Characterization of the insulin sensitivity of ghrelin receptor KO mice using glycemic clamps

    Directory of Open Access Journals (Sweden)

    Morgan Kristen

    2011-01-01

    Full Text Available Abstract Background We and others have demonstrated previously that ghrelin receptor (GhrR knock out (KO mice fed a high fat diet (HFD have increased insulin sensitivity and metabolic flexibility relative to WT littermates. A striking feature of the HFD-fed GhrR KO mouse is the dramatic decrease in hepatic steatosis. To characterize further the underlying mechanisms of glucose homeostasis in GhrR KO mice, we conducted both hyperglycemic (HG and hyperinsulinemic-euglycemic (HI-E clamps. Additionally, we investigated tissue glucose uptake and specifically examined liver insulin sensitivity. Results Consistent with glucose tolerance-test data, in HG clamp experiments, GhrR KO mice showed a reduction in glucose-stimulated insulin release relative to WT littermates. Nevertheless, a robust 1st phase insulin secretion was still achieved, indicating that a healthy β-cell response is maintained. Additionally, GhrR KO mice demonstrated both a significantly increased glucose infusion rate and significantly reduced insulin requirement for maintenance of the HG clamp, consistent with their relative insulin sensitivity. In HI-E clamps, both LFD-fed and HFD-fed GhrR KO mice showed higher peripheral insulin sensitivity relative to WT littermates as indicated by a significant increase in insulin-stimulated glucose disposal (Rd, and decreased hepatic glucose production (HGP. HFD-fed GhrR KO mice showed a marked increase in peripheral tissue glucose uptake in a variety of tissues, including skeletal muscle, brown adipose tissue and white adipose tissue. GhrR KO mice fed a HFD also showed a modest, but significant decrease in conversion of pyruvate to glucose, as would be anticipated if these mice displayed increased liver insulin sensitivity. Additionally, the levels of UCP2 and UCP1 were reduced in the liver and BAT, respectively, in GhrR KO mice relative to WT mice. Conclusions These results indicate that improved glucose homeostasis of GhrR KO mice is

  11. Parameters of glucose metabolism and the aging brain: a magnetization transfer imaging study of brain macro- and micro-structure in older adults without diabetes.

    Science.gov (United States)

    Akintola, Abimbola A; van den Berg, Annette; Altmann-Schneider, Irmhild; Jansen, Steffy W; van Buchem, Mark A; Slagboom, P Eline; Westendorp, Rudi G; van Heemst, Diana; van der Grond, Jeroen

    2015-08-01

    Given the concurrent, escalating epidemic of diabetes mellitus and neurodegenerative diseases, two age-related disorders, we aimed to understand the relation between parameters of glucose metabolism and indices of pathology in the aging brain. From the Leiden Longevity Study, 132 participants (mean age 66 years) underwent a 2-h oral glucose tolerance test to assess glucose tolerance (fasted and area under the curve (AUC) glucose), insulin sensitivity (fasted and AUC insulin and homeostatic model assessment of insulin sensitivity (HOMA-IS)) and insulin secretion (insulinogenic index). 3-T brain MRI was used to detect macro-structural damage (atrophy, white matter hyper-intensities, infarcts and/or micro-bleeds) and magnetization transfer imaging (MTI) to detect loss of micro-structural homogeneity that remains otherwise invisible on conventional MRI. Macro-structurally, higher fasted glucose was significantly associated with white matter atrophy (P = 0.028). Micro-structurally, decreased magnetization transfer ratio (MTR) peak height in gray matter was associated with higher fasted insulin (P = 0.010), AUCinsulin (P = 0.001), insulinogenic index (P = 0.008) and lower HOMA-IS index (P glucose was associated with macro-structural damage, impaired insulin action was associated more strongly with reduced micro-structural brain parenchymal homogeneity. These findings offer some insight into the association between different parameters of glucose metabolism (impairment of which is characteristic of diabetes mellitus) and brain aging.

  12. Glucose oxidase probe as a surface-enhanced Raman scattering sensor for glucose.

    Science.gov (United States)

    Qi, Guohua; Wang, Yi; Zhang, Biying; Sun, Dan; Fu, Cuicui; Xu, Weiqing; Xu, Shuping

    2016-10-01

    Glucose oxidase (GOx) possessing a Raman-active chromophore (flavin adenine dinucleotide) is used as a signal reporter for constructing a highly specific "turn off" surface-enhanced Raman scattering (SERS) sensor for glucose. This sensing chip is made by the electrostatic assembly of GOx over silver nanoparticle (Ag NP)-functionalized SERS substrate through a positively charged polyelectrolyte linker under the pH of 6.86. To trace glucose in blood serum, owing to the reduced pH value caused by the production of gluconic acid in the GOx-catalyzed oxidation reaction, the bonding force between GOx and polyelectrolyte weakens, making GOx drop off from the sensing chip. As a result, the SERS intensity of GOx on the chip decreases along with the concentration of glucose. This glucose SERS sensor exhibits excellent selectivity based on the specific GOx/glucose catalysis reaction and high sensitivity to 1.0 μM. The linear sensing range is 2.0-14.0 mM, which also meets the requirement on the working range of the human blood glucose detection. Using GOx as a probe shows superiority over other organic probes because GOx almost has no toxicity to the biological system. This sensing mechanism can be applied for intracellular in vivo SERS monitoring of glucose in the future. Graphical abstract Glucose oxidase is used as a Raman signal reporter for constructing a highly specific glucose surface-enhanced Raman scattering (SERS) sensor.

  13. Clinical assessment of blood glucose homeostasis in horses: comparison of a continuous glucose monitoring system with a combined intravenous glucose and insulin test protocol.

    Science.gov (United States)

    Johnson, P J; Wiedmeyer, C E; LaCarrubba, A; Messer, N T; Dingfelder, H A; Cogswell, A M; Amorim, J R R; Ganjam, V K

    2011-01-01

    The combined glucose-insulin test (CGIT) is helpful for evaluating insulin sensitivity. A continuous glucose monitoring system (CGMS) reports changes in interstitial glucose concentrations as they occur in the blood. Use of the CGMS minimizes animal contact and may be useful when performing a CGIT. Results obtained using a CGMS are useful for the evaluation of glucose responses during the evaluation of insulin sensitivity in equids. Seven mature, obese ponies. Ponies were equipped with CGMS for determination of interstitial glucose concentrations. Glucose (150 mg/kg, i.v.) and insulin (0.1 U/kg, i.v.) were administered and blood glucose concentrations determined at (minutes after time zero) 1, 5, 15, 25, 35, 45, 60, 75, 90, 105, and 120 with a hand-held glucometer. Blood chemistry results were compared with simultaneously obtained results using CGMS. Concordance coefficients determined for comparison of blood glucose concentrations determined by a hand-held glucometer and those determined by CGMS after the zero time point were 0.623, 0.764, 0.834, 0.854, and 0.818 (for delays of 0, 5, 10, 15, and 20 minutes, respectively). Interstitial glucose concentrations obtained by the CGMS compared favorably to blood glucose concentrations. CGMS may be useful for assessment of glucose dynamics in the CGIT. Copyright © 2010 by the American College of Veterinary Internal Medicine.

  14. Detection of saliva-range glucose concentrations using organic thin-film transistors

    International Nuclear Information System (INIS)

    Elkington, D.; Belcher, W. J.; Dastoor, P. C.; Zhou, X. J.

    2014-01-01

    We describe the development of a glucose sensor through direct incorporation of an enzyme (glucose oxidase) into the gate of an organic thin film transistor (OTFT). We show that glucose diffusion is the key determinant of the device response time and present a mechanism of glucose sensing in these devices that involves protonic doping of the transistor channel via enzymatic oxidation of glucose. The integrated OTFT sensor is sensitive across 4 decades of glucose concentration; a range that encompasses both the blood and salivary glucose concentration levels. As such, this work acts as a proof-of-concept for low-cost printed biosensors for salivary glucose.

  15. Detection of saliva-range glucose concentrations using organic thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Elkington, D.; Belcher, W. J.; Dastoor, P. C.; Zhou, X. J. [Centre for Organic Electronics, University of Newcastle, Callaghan, New South Wales 2308 (Australia)

    2014-07-28

    We describe the development of a glucose sensor through direct incorporation of an enzyme (glucose oxidase) into the gate of an organic thin film transistor (OTFT). We show that glucose diffusion is the key determinant of the device response time and present a mechanism of glucose sensing in these devices that involves protonic doping of the transistor channel via enzymatic oxidation of glucose. The integrated OTFT sensor is sensitive across 4 decades of glucose concentration; a range that encompasses both the blood and salivary glucose concentration levels. As such, this work acts as a proof-of-concept for low-cost printed biosensors for salivary glucose.

  16. An in vitro drug sensitivity test using a higher 3H-TdR incorporation and a modified human tumor stem cell assay

    International Nuclear Information System (INIS)

    Wang Enzhong

    1991-01-01

    An in vitro drug sensitivity test was developed to evaluate the lethal effects of drugs on human pulmonary carcinoma cells (HPCC). This method was a variant and combination of Human Tumor Stem (HTSCA) and a short-term test using 3 H-TdR incorporation. It consisted of a cell containing liquid top layer and a soft agar bottom layer in 24-well microplates. The medium was RPMI 1640 supplemented with 20% malignant pleural effusion, which could enhance 3 H-TdR incorporation into malignant cells. When 50%, 40%, 30% and 30% of cell survival rate defined as sensitivity-threshold for VCR, MMC, DDP and ADM respectively, in the vitro effectiveness were close to those of clinical single-drug treatment in HPCC by Wright et al. This method was also compared with HTSCA in ten human lung cancer cell lines and four pulmonary carcinoma tissues. The agreement rates were 83% and 100% respectively. Thus we presume this system is more useful for oncological clinics than the others

  17. Glucose: the worst of all evils?

    African Journals Online (AJOL)

    occurs secondary to elevated levels of cortisol, epinephrine, norepinephrine ... recovery and higher mortality in stroke patients,14,15,16,17 and an increased morbidity and .... TGC come into play.1,24 Avoiding variable blood glucose and exact.

  18. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... symptoms include the following: High blood glucose High levels of sugar in the urine Frequent urination Increased ... you should check and what your blood glucose levels should be. Checking your blood and then treating ...

  19. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... blood glucose High levels of sugar in the urine Frequent urination Increased thirst Part of managing your ... glucose is above 240 mg/dl, check your urine for ketones. If you have ketones, do not ...

  20. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... can often lower your blood glucose level by exercising. However, if your blood glucose is above 240 ... ketones. If you have ketones, do not exercise. Exercising when ketones are present may make your blood ...

  1. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose ... glucose) Dawn Phenomenon Checking for Ketones Tight Diabetes Control donate en -- A Future Without Diabetes - a-future- ...

  2. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical term for high blood glucose (blood sugar). High ... We Are Research Leaders We Support Your Doctor Student Resources Patient Access to Research Research Resources Practice ...

  3. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day ... DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing ...

  4. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Your Carbs Count Glycemic Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type 1 Diabetes Get ... the technical term for high blood glucose (blood sugar). High blood glucose happens when the body has ...

  5. [Blood glucose self monitoring].

    Science.gov (United States)

    Wascher, Thomas C; Stechemesser, Lars

    2016-04-01

    Self monitoring of blood glucose contributes to the integrated management of diabetes mellitus. It, thus, should be available for all patients with diabetes mellitus type-1 and type-2. Self monitoring of blood glucose improves patients safety, quality of life and glucose control. The current article represents the recommendations of the Austrian Diabetes Association for the use of blood glucose self monitoring according to current scientific evidence.

  6. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Carbohydrate Counting Make Your Carbs Count Glycemic Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type ... Checking Your Blood Glucose A1C and eAG Hypoglycemia (Low blood glucose) Hyperglycemia (High blood glucose) Dawn Phenomenon ...

  7. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... how often you should check and what your blood glucose levels should be. Checking your blood and then treating ... I Treat Hyperglycemia? You can often lower your blood glucose level by exercising. However, if your blood glucose is ...

  8. Electrocatalytic glucose sensor

    Energy Technology Data Exchange (ETDEWEB)

    Gebhardt, U; Luft, G; Mund, K; Preidel, W; Richter, G J

    1983-01-01

    An artificial pancreas consists of an insulin depot, a dosage unit and a glucose sensor. The measurement of the actual glucose concentration in blood is still an unsolved problem. Two methods are described for an electrocatalytic glucose sensor. Under the interfering action of amino acids and urea in-vitro measurements show an error of between 10% and 20%.

  9. Glucose recovery after intranasal glucagon during hypoglycaemia in man

    DEFF Research Database (Denmark)

    Hvidberg, A; Djurup, R; Hilsted, J

    1994-01-01

    to exceed 3 mmol.l-1 was significantly shorter for i.m. glucagon. The mean plasma glucagon level increased faster after i.m. glucagon than after intranasal glucagon, and the levels remained higher throughout the study period. We conclude that glucose recovery was significantly better after i...... endogenous glucose counterregulation, and glucose turnover was estimated by a 3-[3H]-glucose infusion. When hypoglycaemia was reached, the subjects received either i.m. glucagon of pancreatic extraction (1 mg) or intranasal genetically engineered glucagon (2 mg). The incremental values for plasma glucose...... concentrations 15 min after intranasal and i.m. administration of glucagon differed marginally. However, after 5 min the glucose appearance rate, as well as the incremental values for plasma glucose, were significantly higher for the i.m. glucagon treatment. The mean time taken for incremental plasma glucose...

  10. Toward CMOS image sensor based glucose monitoring.

    Science.gov (United States)

    Devadhasan, Jasmine Pramila; Kim, Sanghyo

    2012-09-07

    Complementary metal oxide semiconductor (CMOS) image sensor is a powerful tool for biosensing applications. In this present study, CMOS image sensor has been exploited for detecting glucose levels by simple photon count variation with high sensitivity. Various concentrations of glucose (100 mg dL(-1) to 1000 mg dL(-1)) were added onto a simple poly-dimethylsiloxane (PDMS) chip and the oxidation of glucose was catalyzed with the aid of an enzymatic reaction. Oxidized glucose produces a brown color with the help of chromogen during enzymatic reaction and the color density varies with the glucose concentration. Photons pass through the PDMS chip with varying color density and hit the sensor surface. Photon count was recognized by CMOS image sensor depending on the color density with respect to the glucose concentration and it was converted into digital form. By correlating the obtained digital results with glucose concentration it is possible to measure a wide range of blood glucose levels with great linearity based on CMOS image sensor and therefore this technique will promote a convenient point-of-care diagnosis.

  11. The cortical eye proprioceptive signal modulates neural activity in higher-order visual cortex as predicted by the variation in visual sensitivity

    DEFF Research Database (Denmark)

    Balslev, Daniela; Siebner, Hartwig R; Paulson, Olaf B

    2012-01-01

    target when the right eye was rotated leftwards as compared with when it was rotated rightwards. This effect was larger after S1(EYE)-rTMS than after rTMS of a control area in the motor cortex. The neural response to retinally identical stimuli in this area could be predicted from the changes in visual......Whereas the links between eye movements and the shifts in visual attention are well established, less is known about how eye position affects the prioritization of visual space. It was recently observed that visual sensitivity varies with the direction of gaze and the level of excitability...... in the eye proprioceptive representation in human left somatosensory cortex (S1(EYE)), so that after 1Hz repetitive transcranial magnetic stimulation (rTMS) over S1(EYE), targets presented nearer the center of the orbit are detected more accurately. Here we used whole-brain functional magnetic resonance...

  12. Associations between Ultrasound Measures of Abdominal Fat Distribution and Indices of Glucose Metabolism in a Population at High Risk of Type 2 Diabetes: The ADDITION-PRO Study

    DEFF Research Database (Denmark)

    Philipsen, Annelotte; Jørgensen, Marit E; Vistisen, Dorte

    2015-01-01

    metabolism in a population at high risk of type 2 diabetes. METHODS: A cross-sectional analysis of 1342 participants of the ADDITION-PRO study. We measured visceral adipose tissue and subcutaneous adipose tissue with ultrasonography, anthropometrics and body fat percentage by bioelectrical impedance. Indices...... standard deviation difference in BMI, visceral adipose tissue, waist circumference, waist/height ratio and body fat percentage corresponded approximately to 0.2mmol/l higher fasting glucose, 0.7mmol/l higher 2-hr glucose, 0.06-0.1% higher HbA1c, 30 % lower HOMA index of insulin sensitivity, 20% lower Gutt...

  13. Fat distribution and glucose intolerance among Greenland inuit

    DEFF Research Database (Denmark)

    Jørgensen, Marit Eika; Borch-Johnsen, Knut; Stolk, Ronald

    2013-01-01

    circumference [WC], and percentage of body fat) and the indices of glucose metabolism (fasting and 2-h glucose levels, insulin resistance per homeostasis model assessment [HOMA-IR], and the insulin sensitivity index [ISI0,120]) among Greenland Inuit. RESEARCH DESIGN AND METHODS A total of 3,108 adult Inuit...... associated with glucose intolerance, fasting and 2-h plasma glucose levels, HOMA-IR, and ISI0,120. VAT was more strongly associated with all outcomes than was SAT. After further adjustment for BMI or WC, VAT was associated with glucose intolerance and insulin resistance, whereas there was a trend toward...

  14. Insulin sensitivity deteriorates after short-term lifestyle intervention in the insulin sensitive phenotype of obesity.

    Science.gov (United States)

    Gilardini, Luisa; Vallone, Luciana; Cottafava, Raffaella; Redaelli, Gabriella; Croci, Marina; Conti, Antonio; Pasqualinotto, Lucia; Invitti, Cecilia

    2012-01-01

    To investigate the effects of a 3-month lifestyle intervention on insulin sensitivity and its related cardiometabolic factors in obese patients. Anthropometry, body composition, oral glucose tolerance test, lipids, alanine aminotransferase, insulin sensitivity (insulinogenic index (ISI), homeostasis model assessment, β-cell performance (disposition index)) were evaluated in 263 obese women and 93 obese men before and after 3 months of hypocaloric low fat/high protein diet associated with physical activity 30 min/day. Patients were divided into 3 groups according to the intervention-induced ISI changes: group 1 (decrease), group 2 (stability) and group 3 (increase). Insulin sensitivity and the disposition index were significantly higher before the intervention in group 1 than in group 3. BMI, waist circumference, and fat mass significantly decreased in groups 1 and 3 in both sexes. β-cell performance decreased in group 1 and increased in group 3. Metabolic variables improved in group 3, whereas glucose levels increased in women of group 1. The post-intervention insulin sensitivity was lower in group 1 than in group 3. Lifestyle intervention induces changes in insulin sensitivity and metabolic factors that depend on the pre-intervention degree of insulin sensitivity. Weight loss leads to metabolic benefits in insulin-resistant, obese patients, whereas it may paradoxically worsen the metabolic conditions in the insulin-sensitive phenotype of obesity. Copyright © 2012 S. Karger GmbH, Freiburg.

  15. Bromocriptine and insulin sensitivity in lean and obese subjects

    Directory of Open Access Journals (Sweden)

    L Bahler

    2016-11-01

    Full Text Available Bromocriptine is a glucose-lowering drug, which was shown to be effective in obese subjects with insulin resistance. It is usually administered in the morning. The exact working mechanism of bromocriptine still has to be elucidated. Therefore, in this open-label randomized prospective cross-over mechanistic study, we assessed whether the timing of bromocriptine administration (morning vs evening results in different effects and whether these effects differ between lean and obese subjects. We studied the effect of bromocriptine on insulin sensitivity in 8 lean and 8 overweight subjects using an oral glucose tolerance test. The subjects used bromocriptine in randomized cross-over order for 2 weeks in the morning and 2 weeks in the evening. We found that in lean subjects, bromocriptine administration in the evening resulted in a significantly higher post-prandial insulin sensitivity as compared with the pre-exposure visit (glucose area under the curve (AUC 742 mmol/L * 120 min (695–818 vs 641 (504–750, P = 0.036, AUC for insulin did not change, P = 0.575. In obese subjects, both morning and evening administration of bromocriptine resulted in a significantly higher insulin sensitivity: morning administration in obese: insulin AUC (55,900 mmol/L * 120 min (43,236–96,831 vs 36,448 (25,213–57,711, P = 0.012 and glucose AUC P = 0.069; evening administration in obese: glucose AUC (735 mmol/L * 120 min (614–988 vs 644 (568–829, P = 0.017 and insulin AUC, P = 0.208. In conclusion, bromocriptine increases insulin sensitivity in both lean and obese subjects. In lean subjects, this effect only occurred when bromocriptine was administrated in the evening, whereas in the obese, insulin sensitivity increased independent of the timing of bromocriptine administration.

  16. A catalytically and genetically optimized β-lactamase-matrix based assay for sensitive, specific, and higher throughput analysis of native henipavirus entry characteristics

    Directory of Open Access Journals (Sweden)

    Holbrook Michael R

    2009-07-01

    Full Text Available Abstract Nipah virus (NiV and Hendra virus (HeV are the only paramyxoviruses requiring Biosafety Level 4 (BSL-4 containment. Thus, study of henipavirus entry at less than BSL-4 conditions necessitates the use of cell-cell fusion or pseudotyped reporter virus assays. Yet, these surrogate assays may not fully emulate the biological properties unique to the virus being studied. Thus, we developed a henipaviral entry assay based on a β-lactamase-Nipah Matrix (βla-M fusion protein. We first codon-optimized the bacterial βla and the NiV-M genes to ensure efficient expression in mammalian cells. The βla-M construct was able to bud and form virus-like particles (VLPs that morphologically resembled paramyxoviruses. βla-M efficiently incorporated both NiV and HeV fusion and attachment glycoproteins. Entry of these VLPs was detected by cytosolic delivery of βla-M, resulting in enzymatic and fluorescent conversion of the pre-loaded CCF2-AM substrate. Soluble henipavirus receptors (ephrinB2 or antibodies against the F and/or G proteins blocked VLP entry. Additionally, a Y105W mutation engineered into the catalytic site of βla increased the sensitivity of our βla-M based infection assays by 2-fold. In toto, these methods will provide a more biologically relevant assay for studying henipavirus entry at less than BSL-4 conditions.

  17. Physical activity, fitness, glucose homeostasis, and brain morphology in twins.

    Science.gov (United States)

    Rottensteiner, Mirva; Leskinen, Tuija; Niskanen, Eini; Aaltonen, Sari; Mutikainen, Sara; Wikgren, Jan; Heikkilä, Kauko; Kovanen, Vuokko; Kainulainen, Heikki; Kaprio, Jaakko; Tarkka, Ina M; Kujala, Urho M

    2015-03-01

    The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity. From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses. According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.

  18. UDP-[14C]glucose-labelable polypeptides from pea: Possible components of glucan synthase I activity

    International Nuclear Information System (INIS)

    Ray, P.M.; Dhugga, K.S.; Gallaghar, S.R.

    1989-01-01

    A membrane-bound polypeptide doublet of about 40 kD can be rapidly labeled with UDP-[ 14 C]glucose under the assay conditions for glucan synthase I (GS-I). Label seems covalently bound, and chases when unlabeled UDPG is added; it might represent a covalent intermediate in polysaccharide synthesis. Labeling and GS-I activity show several common features: they co-sediment with Golgi membranes in sucrose gradients; they depend similarly on Mg 2+ or Mn 2+ (not Ca 2+ ); they decrease dramatically from stem apex to base, and are higher in epidermis than internal tissue; they show similar sensitivities to several inhibitors. But the doublet still labels after polysaccharide-synthesizing activity has been destroyed by Triton X-100. The doublet polypeptides might be glucosyl tranferases whose ability to transfer glucose units to a glucan chain is detergent-sensitive, but to accept glucose from UDPG is not; or they might be detergent-insensitive primary glucose acceptors, from which a distinct, detergent-sensitive transferase(s) move(s) these units to glucan chains

  19. Unannounced Meals in the Artificial Pancreas: Detection Using Continuous Glucose Monitoring

    Directory of Open Access Journals (Sweden)

    Charrise M. Ramkissoon

    2018-03-01

    Full Text Available The artificial pancreas (AP system is designed to regulate blood glucose in subjects with type 1 diabetes using a continuous glucose monitor informed controller that adjusts insulin infusion via an insulin pump. However, current AP developments are mainly hybrid closed-loop systems that include feed-forward actions triggered by the announcement of meals or exercise. The first step to fully closing the loop in the AP requires removing meal announcement, which is currently the most effective way to alleviate postprandial hyperglycemia due to the delay in insulin action. Here, a novel approach to meal detection in the AP is presented using a sliding window and computing the normalized cross-covariance between measured glucose and the forward difference of a disturbance term, estimated from an augmented minimal model using an Unscented Kalman Filter. Three different tunings were applied to the same meal detection algorithm: (1 a high sensitivity tuning, (2 a trade-off tuning that has a high amount of meals detected and a low amount of false positives (FP, and (3 a low FP tuning. For the three tunings sensitivities 99 ± 2%, 93 ± 5%, and 47 ± 12% were achieved, respectively. A sensitivity analysis was also performed and found that higher carbohydrate quantities and faster rates of glucose appearance result in favorable meal detection outcomes.

  20. Sleep Deprivation in Young and Healthy Subjects Is More Sensitively Identified by Higher Frequencies of Electrodermal Activity than by Skin Conductance Level Evaluated in the Time Domain

    Directory of Open Access Journals (Sweden)

    Hugo F. Posada-Quintero

    2017-06-01

    Full Text Available We analyzed multiple measures of the autonomic nervous system (ANS based on electrodermal activity (EDA and heart rate variability (HRV for young healthy subjects undergoing 24-h sleep deprivation. In this study, we have utilized the error awareness test (EAT every 2 h (13 runs total, to evaluate the deterioration of performance. EAT consists of trials where the subject is presented words representing colors. Subjects are instructed to press a button (“Go” trials or withhold the response if the word presented and the color of the word mismatch (“Stroop No-Go” trial, or the screen is repeated (“Repeat No-Go” trials. We measured subjects' (N = 10 reaction time to the “Go” trials, and accuracy to the “Stroop No-Go” and “Repeat No-Go” trials. Simultaneously, changes in EDA and HRV indices were evaluated. Furthermore, the relationship between reactiveness and vigilance measures and indices of sympathetic control based on HRV were analyzed. We found the performance improved to a stable level from 6 through 16 h of deprivation, with a subsequently sustained impairment after 18 h. Indices of higher frequencies of EDA related more to vigilance measures, whereas lower frequencies index (skin conductance leve, SCL measured the reactiveness of the subject. We conclude that indices of EDA, including those of the higher frequencies, termed TVSymp, EDASymp, and NSSCRs, provide information to better understand the effect of sleep deprivation on subjects' autonomic response and performance.

  1. Low-protein, high-carbohydrate diet increases glucose uptake and fatty acid synthesis in brown adipose tissue of rats.

    Science.gov (United States)

    Aparecida de França, Suélem; Pavani Dos Santos, Maísa; Nunes Queiroz da Costa, Roger Vinícius; Froelich, Mendalli; Buzelle, Samyra Lopes; Chaves, Valéria Ernestânia; Giordani, Morenna Alana; Pereira, Mayara Peron; Colodel, Edson Moleta; Marlise Balbinotti Andrade, Cláudia; Kawashita, Nair Honda

    2014-04-01

    The aim of this study was to evaluate glucose uptake and the contribution of glucose to fatty acid (FA) synthesis and the glycerol-3-phosphate (G3P) of triacylglycerol synthesis by interscapular brown adipose tissue (IBAT) of low-protein, high-carbohydrate (LPHC) diet-fed rats. LPHC (6% protein; 74% carbohydrate) or control (17% protein; 63% carbohydrate) diets were administered to rats (∼ 100 g) for 15 d. Total FA and G3P synthesis and the synthesis of FA and G3P from glucose were evaluated in vivo by (3)H2O and (14)C-glucose. Sympathetic neural contribution for FA synthesis was evaluated by comparing the synthesis in denervated (7 d before) IBAT with that of the contralateral innervated side. The insulin signaling and β3 adrenergic receptor (β3-AR) contents, as well as others, were determined by Western blot (Student's t test or analysis of variance; P ≤ 0.05). Total FA synthesis in IBAT was 133% higher in the LPHC group and was reduced 85% and 70% by denervation for the LPHC and control groups, respectively. Glucose uptake was 3.5-fold higher in the IBAT of LPHC rats than in that of the control rats, and the contribution of glucose to the total FA synthesis increased by 12% in control rats compared with 18% in LPHC rats. The LPHC diet increased the G3P generation from glucose by 270% and the insulin receptor content and the p-AKT insulin stimulation in IBAT by 120% and reduced the β3-AR content by 50%. The LPHC diet stimulated glucose uptake, both the total rates and the rates derived from glucose-dependent FA and G3P synthesis, by increasing the insulin sensitivity and the sympathetic flux, despite a reduction in the β3-AR content. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. T1ρ-weighted Dynamic Glucose-enhanced MR Imaging in the Human Brain.

    Science.gov (United States)

    Paech, Daniel; Schuenke, Patrick; Koehler, Christina; Windschuh, Johannes; Mundiyanapurath, Sibu; Bickelhaupt, Sebastian; Bonekamp, David; Bäumer, Philipp; Bachert, Peter; Ladd, Mark E; Bendszus, Martin; Wick, Wolfgang; Unterberg, Andreas; Schlemmer, Heinz-Peter; Zaiss, Moritz; Radbruch, Alexander

    2017-12-01

    Purpose To evaluate the ability to detect intracerebral regions of increased glucose concentration at T1ρ-weighted dynamic glucose-enhanced (DGE) magnetic resonance (MR) imaging at 7.0 T. Materials and Methods This prospective study was approved by the institutional review board. Nine patients with newly diagnosed glioblastoma and four healthy volunteers were included in this study from October 2015 to July 2016. Adiabatically prepared chemical exchange-sensitive spin-lock imaging was performed with a 7.0-T whole-body unit with a temporal resolution of approximately 7 seconds, yielding the time-resolved DGE contrast. T1ρ-weighted DGE MR imaging was performed with injection of 100 mL of 20% d-glucose via the cubital vein. Glucose enhancement, given by the relative signal intensity change at T1ρ-weighted MR imaging (DGEρ), was quantitatively investigated in brain gray matter versus white matter of healthy volunteers and in tumor tissue versus normal-appearing white matter of patients with glioblastoma. The median signal intensities of the assessed brain regions were compared by using the Wilcoxon rank-sum test. Results In healthy volunteers, the median signal intensity in basal ganglia gray matter (DGEρ = 4.59%) was significantly increased compared with that in white matter tissue (DGEρ = 0.65%) (P = .028). In patients, the median signal intensity in the glucose-enhanced tumor region as displayed on T1ρ-weighted DGE images (DGEρ = 2.02%) was significantly higher than that in contralateral normal-appearing white matter (DGEρ = 0.08%) (P brain glucose physiology and pathophysiologically increased glucose uptake and may have the potential to provide information about glucose metabolism in tumor tissue. © RSNA, 2017 Online supplemental material is available for this article.

  3. Condensation reactions of glucose and aromatic ring; Glucose to hokokan tono shukugo hanno

    Energy Technology Data Exchange (ETDEWEB)

    Komano, T.; Mashimo, K.; Wainai, T.; Tanaka, C.; Yoshioka, T. [Nihon University, Tokyo (Japan). College of Science and Technology; Sugimoto, Y.; Miki, Y. [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1996-10-28

    For artificial coalification, condensation reactions of aromatic ring and activated compounds produced by dehydrating reaction of glucose were studied experimentally. In heat treatment experiment in water, three reaction specimens such as glucose, glucose and phenol, and glucose and benzaldehyde were fed into an autoclave together with distilled water, and subjected to reaction at 180{degree}C under spontaneous pressure for 50 hours. In hydrogenation experiment, the specimens were fed into an autoclave together with tetradecane and sulfurization catalyst, and subjected to reaction at 350{degree}C under initial pressure of 9.8MPa for 2 hours for gas chromatography (GC) analysis of products. As the experimental result, the reaction between glucose and aromatic ring in heat treatment in water occurred between aromatic ring and active fragment with a mean carbon number of 4-5 produced by decomposition of glucose. The reactivity was higher in benzaldehyde addition than phenol addition. 3 refs., 4 figs., 1 tab.

  4. Designing a highly active soluble PQQ-glucose dehydrogenase for efficient glucose biosensors and biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Durand, Fabien [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Stines-Chaumeil, Claire [Universite de Bordeaux, CNRS, Institut de Biochimie et de Genetique Cellulaires, 1 rue Camille Saint Saens, 33077 Bordeaux Cedex (France); Flexer, Victoria [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Andre, Isabelle [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR5504, F-31400 Toulouse (France); INRA, UMR 792 Ingenierie des Systemes Biologiques et des Procedes, F-31400 Toulouse (France); Mano, Nicolas, E-mail: mano@crpp-bordeaux.cnrs.fr [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France)

    2010-11-26

    Research highlights: {yields} A new mutant of PQQ-GDH designed for glucose biosensors application. {yields} First mutant of PQQ-GDH with higher activity for D-glucose than the Wild type. {yields} Position N428 is a key point to increase the enzyme activity. {yields} Molecular modeling shows that the N428 C mutant displays a better interaction for PQQ than the WT. -- Abstract: We report for the first time a soluble PQQ-glucose dehydrogenase that is twice more active than the wild type for glucose oxidation and was obtained by combining site directed mutagenesis, modelling and steady-state kinetics. The observed enhancement is attributed to a better interaction between the cofactor and the enzyme leading to a better electron transfer. Electrochemical experiments also demonstrate the superiority of the new mutant for glucose oxidation and make it a promising enzyme for the development of high-performance glucose biosensors and biofuel cells.

  5. A 75 g glucose In pregnancy load for diabetic an evaluation screening

    African Journals Online (AJOL)

    1989-08-19

    Aug 19, 1989 ... Screening for impairment of glucose tolerance in pregnancy is mandatory if a ... Organisation our mean glucose value was 8,4 mmol/I. The sensitivity of ... ultrasonographic scan, urine testing and education (including lectures ...

  6. Characterization of different FAD-dependent glucose dehydrogenases for possible use in glucose-based biosensors and biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, Muhammad Nadeem; Beden, Najat; Gorton, Lo [Lund University, Department of Biochemistry and Structural Biology, Lund (Sweden); Leech, Donal [National University of Ireland Galway, School of Chemistry, Galway (Ireland); Sygmund, Christoph; Ludwig, Roland [BOKU-University of Natural Resources and Life Sciences Vienna, Food Biotechnology Laboratory, Department of Food Sciences and Technology, Wien (Austria)

    2012-02-15

    In this study, different flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenases (FADGDHs) were characterized electrochemically after ''wiring'' them with an osmium redox polymer [Os(4,4'-dimethyl-2,2'-bipyridine){sub 2}(PVI){sub 10}Cl]{sup +} on graphite electrodes. One tested FADGDH was that recently discovered in Glomerella cingulata (GcGDH), another was the recombinant form expressed in Pichia pastoris (rGcGDH), and the third was a commercially available glycosylated enzyme from Aspergillus sp. (AspGDH). The performance of the Os-polymer ''wired'' GDHs on graphite electrodes was tested with glucose as the substrate. Optimal operational conditions and analytical characteristics like sensitivity, linear ranges and current density of the different FADGDHs were determined. The performance of all three types of FADGDHs was studied at physiological conditions (pH 7.4). The current densities measured at a 20 mM glucose concentration were 494 {+-} 17, 370 {+-} 24, and 389 {+-} 19 {mu}A cm{sup -2} for GcGDH, rGcGDH, and AspGDH, respectively. The sensitivities towards glucose were 2.16, 1.90, and 1.42 {mu}A mM{sup -1} for GcGDH, rGcGDH, and AspGDH, respectively. Additionally, deglycosylated rGcGDH (dgrGcGDH) was investigated to see whether the reduced glycosylation would have an effect, e.g., a higher current density, which was indeed found. GcGDH/Os-polymer modified electrodes were also used and investigated for their selectivity for a number of different sugars. (orig.)

  7. Characterization of different FAD-dependent glucose dehydrogenases for possible use in glucose-based biosensors and biofuel cells.

    Science.gov (United States)

    Zafar, Muhammad Nadeem; Beden, Najat; Leech, Dónal; Sygmund, Christoph; Ludwig, Roland; Gorton, Lo

    2012-02-01

    In this study, different flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenases (FADGDHs) were characterized electrochemically after "wiring" them with an osmium redox polymer [Os(4,4'-dimethyl-2,2'-bipyridine)(2)(PVI)(10)Cl](+) on graphite electrodes. One tested FADGDH was that recently discovered in Glomerella cingulata (GcGDH), another was the recombinant form expressed in Pichia pastoris (rGcGDH), and the third was a commercially available glycosylated enzyme from Aspergillus sp. (AspGDH). The performance of the Os-polymer "wired" GDHs on graphite electrodes was tested with glucose as the substrate. Optimal operational conditions and analytical characteristics like sensitivity, linear ranges and current density of the different FADGDHs were determined. The performance of all three types of FADGDHs was studied at physiological conditions (pH 7.4). The current densities measured at a 20 mM glucose concentration were 494 ± 17, 370 ± 24, and 389 ± 19 μA cm(-2) for GcGDH, rGcGDH, and AspGDH, respectively. The sensitivities towards glucose were 2.16, 1.90, and 1.42 μA mM(-1) for GcGDH, rGcGDH, and AspGDH, respectively. Additionally, deglycosylated rGcGDH (dgrGcGDH) was investigated to see whether the reduced glycosylation would have an effect, e.g., a higher current density, which was indeed found. GcGDH/Os-polymer modified electrodes were also used and investigated for their selectivity for a number of different sugars.

  8. Acute effects of feeding fructose, glucose and sucrose on blood lipid levels and systemic inflammation.

    Science.gov (United States)

    Jameel, Faizan; Phang, Melinda; Wood, Lisa G; Garg, Manohar L

    2014-12-16

    Recent studies have demonstrated a relationship between fructose consumption and risk of developing metabolic syndrome. Mechanisms by which dietary fructose mediates metabolic changes are poorly understood. This study compared the effects of fructose, glucose and sucrose consumption on post-postprandial lipemia and low grade inflammation measured as hs-CRP. This was a randomized, single blinded, cross-over trial involving healthy subjects (n=14). After an overnight fast, participants were given one of 3 different isocaloric drinks, containing 50 g of either fructose or glucose or sucrose dissolved in water. Blood samples were collected at baseline, 30, 60 and 120 minutes post intervention for the analysis of blood lipids, glucose, insulin and high sensitivity C-reactive protein (hs-CRP). Glucose and sucrose supplementation initially resulted in a significant increase in glucose and insulin levels compared to fructose supplementation and returned to near baseline values within 2 hours. Change in plasma cholesterol, LDL and HDL-cholesterol (measured as area under curve, AUC) was significantly higher when participants consumed fructose compared with glucose or sucrose (PAUC for plasma triglyceride levels however remained unchanged regardless of the dietary intervention. Change in AUC for hs-CRP was also significantly higher in subjects consuming fructose compared with those consuming glucose (P<0.05), but not sucrose (P=0.07). This study demonstrates that fructose as a sole source of energy modulates plasma lipids and hsCRP levels in healthy individuals. The significance of increase in HDL-cholesterol with a concurrent increase in LDL-cholesterol and elevated hs-CRP levels remains to be delineated when considering health effects of feeding fructose-rich diets. ACTRN12614000431628.

  9. Elevated 1-hour postload plasma glucose levels identify subjects with normal glucose tolerance but impaired β-cell function, insulin resistance, and worse cardiovascular risk profile: the GENFIEV study.

    Science.gov (United States)

    Bianchi, Cristina; Miccoli, Roberto; Trombetta, Maddalena; Giorgino, Francesco; Frontoni, Simona; Faloia, Emanuela; Marchesini, Giulio; Dolci, Maria A; Cavalot, Franco; Cavallo, Gisella; Leonetti, Frida; Bonadonna, Riccardo C; Del Prato, Stefano

    2013-05-01

    In subjects with normal glucose tolerance (NGT) 1-hour postload plasma glucose (1-h oral glucose tolerance test [OGTT]) of >155 mg/dL predicts type 2 diabetes (T2DM) and is associated with subclinical atherosclerosis. The purpose of this study was to evaluate β-cell function, insulin resistance, and cardiovascular risk profile in subjects with NGT with a 1-h OGTT glucose of >155 mg/dL. The GENFIEV (Genetics, PHYsiopathology, and Evolution of Type 2 diabetes) study is a multicenter study recruiting individuals at high risk of T2DM. A total of 926 subjects underwent a 75-g OGTT for assessment of plasma glucose and C-peptide for mathematical modeling of β-cell function (derivative and proportional control). Fasting insulin, lipid profile, and clinical parameters were determined as well. A 1-hour OGTT glucose of >155 mg/dL was found in 39% of subjects with NGT, 76% with impaired fasting glucose (IFG), 90% with impaired glucose tolerance (IGT), and 99% and 98% with IFG + IGT or newly diagnosed T2DM, respectively. Among subjects with NGT (n = 474), those with 1-hour OGTT glucose of >155 mg/dL were more insulin-resistant and had worse β-cell function than those with 1-hour OGTT glucose of ≤155 mg/dL. Moreover, glycosylated hemoglobin, blood pressure, low-density lipoprotein cholesterol, and triglycerides were higher in subjects with NGT with 1-hour OGTT glucose of >155 mg/dL, whereas high-density lipoprotein cholesterol was lower compared with that in subjects with NGT with 1-hour OGTT glucose of ≤155 mg/dL. Compared with subjects with IGT, those with NGT with 1-hour OGTT glucose of >155 mg/dL had comparable cardiovascular risk profile and insulin resistance but slightly better β-cell function. Among subjects with NGT, those with 1-hour OGTT glucose of >155 mg/dL showed lower insulin sensitivity, impaired β-cell function, and worse cardiovascular risk profile and therefore are at greater risk of developing T2DM and cardiovascular disease.

  10. Effects of dietary glucose and sodium chloride on intestinal glucose absorption of common carp (Cyprinus carpio L.).

    Science.gov (United States)

    Qin, Chaobin; Yang, Liping; Zheng, Wenjia; Yan, Xiao; Lu, Ronghua; Xie, Dizhi; Nie, Guoxing

    2018-01-08

    The co-transport of sodium and glucose is the first step for intestinal glucose absorption. Dietary glucose and sodium chloride (NaCl) may facilitate this physiological process in common carp (Cyprinus carpio L.). To test this hypothesis, we first investigated the feeding rhythm of intestinal glucose absorption. Carps were fed to satiety once a day (09:00 a.m.) for 1 month. Intestinal samples were collected at 01:00, 05:00, 09:00, 13:00, 17:00 and 21:00. Result showed that food intake greatly enhanced sodium/glucose cotransporter 1 (SGLT1) and glucose transporter type 2 (GLUT2) expressions, and improved glucose absorption, with highest levels at 09:00 a.m.. Then we designed iso-nitrogenous and iso-energetic diets with graded levels of glucose (10%, 20%, 30%, 40% and 50%) and NaCl (0%, 1%, 3% and 5%), and submitted to feeding trial for 10 weeks. The expressions of SGLT1 and GLUT2, brush border membrane vesicles (BBMVs) glucose transport and intestinal villus height were determined after the feeding trial. Increasing levels of dietary glucose and NaCl up-regulated mRNA and protein levels of SGLT1 and GLUT2, enhanced BBMVs glucose transport in the proximal, mid and distal intestine. As for histological adaptive response, however, high-glucose diet prolonged while high-NaCl diet shrank intestinal villus height. Furthermore, we also found that higher mRNA levels of SGLT1 and GLUT2, higher glucose transport capacity of BBMVs, and higher intestinal villus were detected in the proximal and mid intestine, compared to the distal part. Taken together, our study indicated that intestinal glucose absorption in carp was primarily occurred in the proximal and mid intestine, and increasing levels of dietary glucose and NaCl enhanced intestinal glucose absorption in carp. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Genetic variation of fasting glucose and changes in glycemia in response to 2-year weight-loss diet intervention: the POUNDS Lost trial

    Science.gov (United States)

    Wang, Tiange; Huang, Tao; Zheng, Yan; Rood, Jennifer; Bray, George A.; Sacks, Frank M.; Qi, Lu

    2016-01-01

    Objective Weight loss intervention through diet modification has been widely used to improve obesity-related hyperglycemia; however, little is known about whether genetic variation modifies the intervention effect. We examined the interaction between weight-loss diets and genetic variation of fasting glucose on changes in glycemic traits in a dietary intervention trial. Research Design and Methods The Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial is a randomized, controlled 2-year weight-loss trial. We assessed overall genetic variation of fasting glucose by calculating a genetic risk score (GRS) based on 14 fasting glucose-associated single nucleotide polymorphisms, and examined the progression in fasting glucose and insulin levels, and insulin resistance and insulin sensitivity in 733 adults from this trial. Results The GRS was associated with 6-month changes in fasting glucose (Pfasting insulin (P=0.042), homeostasis model assessment of insulin resistance (HOMA-IR, P=0.009) and insulin sensitivity (HOMA-S, P=0.043). We observed significant interaction between the GRS and dietary fat on 6-month changes in fasting glucose, HOMA-IR and HOMA-S after multivariable adjustment (P-interaction=0.007, 0.045, and 0.028, respectively). After further adjustment for weight loss, the interaction remained significant on change in fasting glucose (P=0.015). In the high-fat diet group, participants in the highest GRS tertile showed increased fasting glucose, whereas participants in the lowest tertile showed decreased fasting glucose (P-trend<0.001); in contrast, the genetic association was not significant in the low-fat diet group (P-trend=0.087). Conclusions Our data suggest that participants with a higher genetic risk may benefit more by eating a low-fat diet to improve glucose metabolism. PMID:27113490

  12. Fabrication of Amperometric Glucose Sensor Using Glucose Oxidase-Cellulose Nanofiber Aqueous Solution.

    Science.gov (United States)

    Yasuzawa, Mikito; Omura, Yuya; Hiura, Kentaro; Li, Jiang; Fuchiwaki, Yusuke; Tanaka, Masato

    2015-01-01

    Cellulose nanofiber aqueous solution, which remained virtually transparent for more than one week, was prepared by using the clear upper layer of diluted cellulose nanofiber solution produced by wet jet milling. Glucose oxidase (GOx) was easily dissolved in this solution and GOx-immobilized electrode was easily fabricated by simple repetitious drops of GOx-cellulose solution on the surface of a platinum-iridium electrode. Glucose sensor properties of the obtained electrodes were examined in phosphate buffer solution of pH 7.4 at 40°C. The obtained electrode provided a glucose sensor response with significantly high response speed and good linear relationship between glucose concentration and response current. After an initial decrease of response sensitivity for a few days, relatively constant sensitivity was obtained for about 20 days. Nevertheless, the influence of electroactive compounds such as ascorbic acid, uric acid and acetoaminophen were not negletable.

  13. Estrogens modulate ventrolateral ventromedial hypothalamic glucose-inhibited neurons

    Directory of Open Access Journals (Sweden)

    Ammy M. Santiago

    2016-10-01

    Full Text Available Objective: Brain regulation of glucose homeostasis is sexually dimorphic; however, the impact sex hormones have on specific neuronal populations within the ventromedial hypothalamic nucleus (VMN, a metabolically sensitive brain region, has yet to be fully characterized. Glucose-excited (GE and -inhibited (GI neurons are located throughout the VMN and may play a critical role in glucose and energy homeostasis. Within the ventrolateral portion of the VMN (VL-VMN, glucose sensing neurons and estrogen receptor (ER distributions overlap. We therefore tested the hypothesis that VL-VMN glucose sensing neurons were sexually dimorphic and regulated by 17β-estradiol (17βE. Methods: Electrophysiological recordings of VL-VMN glucose sensing neurons in brain slices isolated from age- and weight-matched female and male mice were performed in the presence and absence of 17βE. Results: We found a new class of VL-VMN GI neurons whose response to low glucose was transient despite continued exposure to low glucose. Heretofore, we refer to these newly identified VL-VMN GI neurons as ‘adapting’ or AdGI neurons. We found a sexual dimorphic response to low glucose, with male nonadapting GI neurons, but not AdGI neurons, responding more robustly to low glucose than those from females. 17βE blunted the response of both nonadapting GI and AdGI neurons to low glucose in both males and females, which was mediated by activation of estrogen receptor β and inhibition of AMP-activated kinase. In contrast, 17βE had no impact on GE or non-glucose sensing neurons in either sex. Conclusion: These data suggest sex differences and estrogenic regulation of VMN hypothalamic glucose sensing may contribute to the sexual dimorphism in glucose homeostasis. Author Video: Author Video Watch what authors say about their articles Keywords: 17β-estradiol, AMP-activated kinase, Glucose excited neurons, Glucose inhibited neurons, Ventromedial hypothalamic nucleus, Sexual dimorphism

  14. Measuring brain glucose phosphorylation with labeled glucose

    International Nuclear Information System (INIS)

    Brondsted, H.E.; Gjedde, A.

    1988-01-01

    This study tested whether glucose labeled at the C-6 position generates metabolites that leave brain so rapidly that C-6-labeled glucose cannot be used to measure brain glucose phosphorylation (CMRGlc). In pentobarbital-anesthetized rats, the parietal cortex uptake of [ 14 C]glucose labeled in the C-6 position was followed for times ranging from 10 s to 60 min. We subtracted the observed radioactivity from the radioactivity expected with no loss of labeled metabolites from brain by extrapolation of glucose uptake in an initial period when loss was negligible. The observed radioactivity was a monoexponentially declining function of the total radioactivity expected in the absence of metabolite loss. The constant of decline was 0.0077.min-1 for parietal cortex. Metabolites were lost from the beginning of the experiment. However, with correction for the loss of labeled metabolites, it was possible to determine an average CMRGlc between 4 and 60 min of circulation of 64 +/- 4 (SE; n = 49) mumol.hg-1.min-1

  15. On the issue of higher human sensitivity to carcinogenic substances in early childhood; Zur Frage einer hoeheren Empfindlichkeit von Kindern gegenueber krebserzeugenden Stoffen

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, K [comp.

    1998-09-01

    Age-dependent carcinogenesis in humans has been proven with high probability for a number of substances investigated within one or several model systems. Sometimes, very high tumor incidence after short exposure time was observed. Extreme differences were found in some models. (A) Vinyl chloride, Maltoni et al.,1981: 6000 ppm, hepatic angiosarcoma incidence: - Exposure for 4 weeks, from day 1: 40.5 %, - exposure for 4 weeks, from week 13: 0%, - exposure for 52 weeks, from week 13: 22%. Hepatoma incidence: - Exposure for 4 weeks, from day 1: 47.6%, exposure for 4 weeks, from week 13: 0%, exposure for 52 weeks, from week 13: 1.7%. (B) Diethyl nitrosamine, Dyroff et al., 1986: (DEN + phenobarbital), hepatic carcinoma after exposure of rats for 6 weeks: - as from 4 weeks of age: 100% incidence, - as from 8 weeks of age: 0% incidence. (C) Benzopyrene, Vesselinovitch et al., 1975: Hepatic tumor incidence after single, parenteral administration to rats: - at day 1: males: 81%, females: 18%, - at day 42: males: 9%, females: 0%. As is shown by the study on vinyl chloride by Maltoni et al., the same exposure concentration may lead to higher tumor incidence in young animals after short exposure times than it does in long-term experiments with adult animals. Genetic toxicity was detected for all substances, except for saccharin. So it can be assumed that the mechanism of carcinogenesis has an essential influence on the age-dependence. This conclusion agrees well with mechanistic approaches. (orig./CB) [German] Fuer eine Reihe von Schadstoffen ist eine Altersabhaengigkeit der Kanzerogenese mit hoher Wahrscheinlichkeit in einem oder mehreren Modellsystemen gezeigt worden. Dabei wurden zum Teil bereits nach kurzer Expositionszeit sehr hohe Tumorausbeuten erzielt. Extreme Unterschiede wurden in folgenden Modellen beobachtet. (A) Vinylchlorid, Maltoni et al., 1981: 6000 ppm, Inzidenz Leberangiosarkome: - Exposition ueber 4 Wochen ab Tag 1: 40,5%, - Exposition ueber 4 Wochen ab 13

  16. Favorable glucose tolerance and lower prevalence of metabolic syndrome in offspring without diabetes mellitus of nonagenarian siblings: the Leiden longevity study.

    Science.gov (United States)

    Rozing, Maarten P; Westendorp, Rudi G J; de Craen, Anton J M; Frölich, Marijke; de Goeij, Moniek C M; Heijmans, Bastiaan T; Beekman, Marian; Wijsman, Carolien A; Mooijaart, Simon P; Blauw, Gerard-Jan; Slagboom, P Eline; van Heemst, Diana

    2010-03-01

    To explore measures of metabolic syndrome and glucose metabolism in families with exceptional longevity. Case-control study. A university hospital in Leiden, the Netherlands. One hundred twenty-one offspring of nonagenarian siblings, who were enriched for familial factors promoting longevity, and 113 of their partners. No subject had diabetes mellitus. Prevalence of metabolic syndrome was determined according to the criteria of the Third Report of the National Cholesterol Education Program. Glucose tolerance was assessed according to a 2-hour oral glucose tolerance test. The offspring of nonagenarians siblings had a lower prevalence of metabolic syndrome (P=.03), similar body composition, lower mean fasting blood glucose levels (4.99 vs 5.16 mmol/L; P=.01), lower mean fasting insulin levels (5.81 vs 6.75 mU/L; P=.04), a higher mean homeostasis model assessment of insulin sensitivity (0.78 vs 0.65; P=.02), and a more-favorable glucose tolerance (mean area under the receiver operating characteristic curve for glucose (13.2 vs 14.3; P=.007) than their partners. No significant differences were observed between the offspring and their partners in beta-cell function (insulogenic index 13.6 vs 12.5; P=.38). Despite similar body composition, the offspring of nonagenarian siblings showed a lower prevalence of metabolic syndrome and better glucose tolerance than their partners, centralizing the role of favorable glucose metabolism in familial longevity.

  17. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Complications Neuropathy Foot Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More ...

  18. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)

    2017-01-01

    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  19. Development of Silicalite/Glucose Oxidase-Based Biosensor and Its Application for Glucose Determination in Juices and Nectars

    Science.gov (United States)

    Dudchenko, Oleksandr Ye; Pyeshkova, Viktoriya M.; Soldatkin, Oleksandr O.; Akata, Burcu; Kasap, Berna O.; Soldatkin, Alexey P.; Dzyadevych, Sergei V.

    2016-02-01

    The application of silicalite for improvement of enzyme adsorption on new stainless steel electrodes is reported. Glucose oxidase (GOx) was immobilized by two methods: cross-linking by glutaraldehyde (GOx-GA) and cross-linking by glutaraldehyde along with GOx adsorption on silicalite-modified electrode (SME) (GOx-SME-GA). The GOx-SME-GA biosensors were characterized by a four- to fivefold higher sensitivity than GOx-GA biosensor. It was concluded that silicalite together with GA sufficiently enhances enzyme adhesion on stainless steel electrodes. The developed GOx-SME-GA biosensors were characterized by good reproducibility of biosensor preparation (relative standard deviation (RSD)—18 %), improved signal reproducibility (RSD of glucose determination was 7 %), and good storage stability (29 % loss of activity after 18-day storage). A series of fruit juices and nectars was analyzed using GOx-SME-GA biosensor for determination of glucose concentration. The obtained results showed good correlation with the data of high-performance liquid chromatography (HPLC) ( R = 0.99).

  20. Blood plasma separation in ZnO nanoflowers-supported paper based microfluidic for glucose sensing

    Science.gov (United States)

    Muhimmah, Luthviyah Choirotul; Roekmono, Hadi, Harsono; Yuwono, Rio Akbar; Wahyuono, Ruri Agung

    2018-04-01

    Blood plasma separation is essential to analyze and quantify the bio-substances in the human blood and hence, allows for diagnosing various diseases. This paper presents the two layer paper-based microfluidic analytical devices coated with ZnO nanoflowers (ZnO NF-µPAD) for a rapid blood plasma separation and glucose sensing. Plasma separation in ZnO NF-µPAD was evaluated experimentally and numerically using computational fluid dynamics package for a flow over porous networks. Glucose detection was carried out using Fourier-transform infrared (FTIR) measurements. The glucose concentrations in the red blood samples investigated here vary in the range of 150 - 310 mg.dl-1. The plasma separation process on ZnO NF-μPAD requires 240 ± 93 s. The spectroscopic data reveals that the IR absorptions and Raman signals at the typical vibrational frequencies of glucose are increasing at higher glucose concentration. After subtraction from absorption background arising from ZnO NF and the paper, linearly increasing IR absorption (913 and 1349 cm-1) and Raman signals (1346 and 1461 cm-1) are observable with a relatively good sensitivity.

  1. Ambient Air Pollutants Have Adverse Effects on Insulin and Glucose Homeostasis in Mexican Americans

    Science.gov (United States)

    Chen, Zhanghua; Salam, Muhammad T.; Toledo-Corral, Claudia; Watanabe, Richard M.; Xiang, Anny H.; Buchanan, Thomas A.; Habre, Rima; Bastain, Theresa M.; Lurmann, Fred; Wilson, John P.; Trigo, Enrique

    2016-01-01

    OBJECTIVE Recent studies suggest that air pollution plays a role in type 2 diabetes (T2D) incidence and mortality. The underlying physiological mechanisms have yet to be established. We hypothesized that air pollution adversely affects insulin sensitivity and secretion and serum lipid levels. RESEARCH DESIGN AND METHODS Participants were selected from BetaGene (n = 1,023), a study of insulin resistance and pancreatic β-cell function in Mexican Americans. All participants underwent DXA and oral and intravenous glucose tolerance tests and completed dietary and physical activity questionnaires. Ambient air pollutant concentrations (NO2, O3, and PM2.5) for short- and long-term periods were assigned by spatial interpolation (maximum interpolation radius of 50 km) of data from air quality monitors. Traffic-related air pollution from freeways (TRAP) was estimated using the dispersion model as NOx. Variance component models were used to analyze individual and multiple air pollutant associations with metabolic traits. RESULTS Short-term (up to 58 days cumulative lagged averages) exposure to PM2.5 was associated with lower insulin sensitivity and HDL-to-LDL cholesterol ratio and higher fasting glucose and insulin, HOMA-IR, total cholesterol, and LDL cholesterol (LDL-C) (all P ≤ 0.036). Annual average PM2.5 was associated with higher fasting glucose, HOMA-IR, and LDL-C (P ≤ 0.043). The effects of short-term PM2.5 exposure on insulin sensitivity were largest among obese participants. No statistically significant associations were found between TRAP and metabolic outcomes. CONCLUSIONS Exposure to ambient air pollutants adversely affects glucose tolerance, insulin sensitivity, and blood lipid concentrations. Our findings suggest that ambient air pollutants may contribute to the pathophysiology in the development of T2D and related sequelae. PMID:26868440

  2. Sleep duration and sleep quality are associated differently with alterations of glucose homeostasis

    DEFF Research Database (Denmark)

    Byberg, Stine; Hansen, Anne-Louise Smidt; Christensen, Dirk Lund

    2012-01-01

    Abstract Aims  Studies suggest that inadequate sleep duration and poor sleep quality increase the risk of impaired glucose regulation and diabetes. However, associations with specific markers of glucose homeostasis are less well explained. The objective of this study was to explore possible...... associations of sleep duration and sleep quality with markers of glucose homeostasis and glucose tolerance status in a healthy population-based study sample. Methods  The study comprised 771 participants from the Danish, population-based cross-sectional ‘Health2008’ study. Sleep duration and sleep quality were...... measured by self-report. Markers of glucose homeostasis were derived from a 3-point oral glucose tolerance test and included fasting plasma glucose, 2-h plasma glucose, HbA1c, two measures of insulin sensitivity (the insulin sensitivity index0,120 and homeostasis model assessment of insulin sensitivity...

  3. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... by Mail Close www.diabetes.org > Living With Diabetes > Treatment and Care > Blood Glucose Testing Share: Print Page ... and-how-tos, . In this section Living With Diabetes Treatment and Care Blood Glucose Testing Checking Your Blood ...

  4. Blood Glucose Determination

    DEFF Research Database (Denmark)

    Lippi, Giuseppe; Nybo, Mads; Cadamuro, Janne

    2018-01-01

    The measurement of fasting plasma glucose may be biased by a time-dependent decrease of glucose in blood tubes, mainly attributable to blood cell metabolism when glycolysis is not rapidly inhibited or blood cells cannot be rapidly separated from plasma. Although glycolysis inhibitors such as sodium...

  5. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy 8 Tips for ... is checking your blood glucose often. Ask your doctor how often you should ... associated with hyperglycemia. How Do I Treat Hyperglycemia? ...

  6. Brain Glucose Metabolism Controls Hepatic Glucose and Lipid Production

    OpenAIRE

    Lam, Tony K.T.

    2007-01-01

    Brain glucose-sensing mechanisms are implicated in the regulation of feeding behavior and hypoglycemic-induced hormonal counter-regulation. This commentary discusses recent findings indicating that the brain senses glucose to regulate both hepatic glucose and lipid production.

  7. Continuous glucose monitoring microsensor with a nanoscale conducting matrix and redox mediator

    Science.gov (United States)

    Pesantez, Daniel

    vitro testing for glucose shows increasing current with increasing analyte concentration. Testing the glucose microsensor with known concentrations of glucose over a period of 48 hours demonstrated both the potential durability and sensitivity of the device. Unknown/blind in vitro glucose experiments showed the reproducibility and accuracy of the microsensor to detect various glucose levels. Thinner polymer matrix films lead to better sensing performance during in vitro tests (0.6nA/mM lower limit sensitivity and 0.2nA/mM upper limit sensitivity). In vitro experiments using electroactive ascorbic acid (AA) and uric acid (UA) showed the selectivity of the sensor for glucose. In an effort to reduce the sensor's oxidation potential (0.7V) and noise, a second generation electron transfer approach was developed by incorporating into a modified Platinum WE with a nanoscale PPy and GOx matrix, a redox mediator. Ferrocene (Fc) was selected as the artificial electron carrier, substituting molecular oxygen in the enzymatic reaction. The incorporation of Fc into the polymer matrix is done by a simple electrochemical synthesis. Modifications in the microsensor design, materials and fabrication process are presented. Experiments with the new sensor generation resulted in higher sensitivity values (22.8nA/mM lower limit sensitivity and 12.5nA/mM upper limit sensitivity) for glucose and noise was further eliminated by operating the sensor at a lower oxidation potential (0.3V). The final experimental work consisted of preliminary ex vivo tests with the MetaSense microdevice on bovine kidney samples, which showed a qualitatively correlation between glucose consumption trend profile during preservation and viability histology outcome.

  8. Associations between ultrasound measures of abdominal fat distribution and indices of glucose metabolism in a population at high risk of type 2 diabetes: the ADDITION-PRO study.

    Directory of Open Access Journals (Sweden)

    Annelotte Philipsen

    Full Text Available Visceral adipose tissue measured by CT or MRI is strongly associated with an adverse metabolic risk profile. We assessed whether similar associations can be found with ultrasonography, by quantifying the strength of the relationship between different measures of obesity and indices of glucose metabolism in a population at high risk of type 2 diabetes.A cross-sectional analysis of 1342 participants of the ADDITION-PRO study. We measured visceral adipose tissue and subcutaneous adipose tissue with ultrasonography, anthropometrics and body fat percentage by bioelectrical impedance. Indices of glucose metabolism were derived from a three point oral glucose tolerance test. Linear regression of obesity measures on indices of glucose metabolism was performed.Mean age was 66.2 years, BMI 26.9kg/m2, subcutaneous adipose tissue 2.5cm and visceral adipose tissue 8.0cm. All measures of obesity were positively associated with indicators of glycaemia and inversely associated with indicators of insulin sensitivity. Associations were of equivalent magnitude except for subcutaneous adipose tissue and the visceral/subcutaneous adipose tissue ratio, which showed weaker associations. One standard deviation difference in BMI, visceral adipose tissue, waist circumference, waist/height ratio and body fat percentage corresponded approximately to 0.2mmol/l higher fasting glucose, 0.7mmol/l higher 2-hr glucose, 0.06-0.1% higher HbA1c, 30 % lower HOMA index of insulin sensitivity, 20% lower Gutt's index of insulin sensitivity, and 100 unit higher Stumvoll's index of beta-cell function. After adjustment for waist circumference visceral adipose tissue was still significantly associated with glucose intolerance and insulin resistance, whereas there was a trend towards inverse or no associations with subcutaneous adipose tissue. After adjustment, a 1cm increase in visceral adipose tissue was associated with ~5% lower insulin sensitivity (p≤0.0004 and ~0.18mmol/l higher 2-hr

  9. Nanomaterials in glucose sensing

    CERN Document Server

    Burugapalli, Krishna

    2013-01-01

    The smartness of nano-materials is attributed to their nanoscale and subsequently unique physicochemical properties and their use in glucose sensing has been aimed at improving performance, reducing cost and miniaturizing the sensor and its associated instrumentation. So far, portable (handheld) glucose analysers were introduced for hospital wards, emergency rooms and physicians' offices; single-use strip systems achieved nanolitre sampling for painless and accurate home glucose monitoring; advanced continuous monitoring devices having 2 to 7 days operating life are in clinical and home use; and continued research efforts are being made to develop and introduce increasingly advanced glucose monitoring systems for health as well as food, biotechnology, cell and tissue culture industries. Nanomaterials have touched every aspect of biosensor design and this chapter reviews their role in the development of advanced technologies for glucose sensing, and especially for diabetes. Research shows that overall, nanomat...

  10. Clinical Observations of Abnormal Glucose Tolerance in Hyperthyroidism

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Ja; Lee, Hong Kyu [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1969-09-15

    Plasma glucose levels before and after oral glucose administration have been compared in g group of 76 thyrotoxic subjects and a group of 8 normal control subjects in order to study the effect of glucose loading in thyrotoxicosis. Following were the results: 1) The mean fasting plasma glucose level was elevated in thyrotoxic group (95.5 mg%) compared to normal control group (88 mg%). 2) The peak of glucose tolerance curve is at 30 minutes after glucose administration in both groups, but its mean value was 44 mg% higher in thyrotoxic group than in control group. 3) The plasma glucose levels returned towards the fasting level in the later stage of the test more rapidly in thyrotoxic group than in control group. 4) 69.6% of oral glucose tolerance tests were impaired in the thyrotoxic group, and the occurrence of abnormal glucose tolerance could be related to the degree of thyrotoxicity, sex and age. 5) The mechanisms of the impaired glucose tolerance in thyrotoxicosis are thought to be related to an increased rate of glucose absorption from gastrointestinal tract, abnormal liver function with decreased hepatic glycogenesis, increased glucose oxidation, decreased pancreatic release of insulin, and genetic relationship between diabetes and thyrotoxicosis.

  11. Coexistence of insulin resistance and increased glucose tolerance in pregnant rats: a physiological mechanism for glucose maintenance.

    Science.gov (United States)

    Carrara, Marcia Aparecida; Batista, Márcia Regina; Saruhashi, Tiago Ribeiro; Felisberto, Antonio Machado; Guilhermetti, Marcio; Bazotte, Roberto Barbosa

    2012-06-06

    The contribution of insulin resistance (IR) and glucose tolerance to the maintenance of blood glucose levels in non diabetic pregnant Wistar rats (PWR) was investigated. PWR were submitted to conventional insulin tolerance test (ITT) and glucose tolerance test (GTT) using blood sample collected 0, 10 and 60 min after intraperitoneal insulin (1 U/kg) or oral (gavage) glucose (1g/kg) administration. Moreover, ITT, GTT and the kinetics of glucose concentration changes in the fed and fasted states were evaluated with a real-time continuous glucose monitoring system (RT-CGMS) technique. Furthermore, the contribution of the liver glucose production was investigated. Conventional ITT and GTT at 0, 7, 14 and 20 days of pregnancy revealed increased IR and glucose tolerance after 20 days of pregnancy. Thus, this period of pregnancy was used to investigate the kinetics of glucose changes with the RT-CGMS technique. PWR (day 20) exhibited a lower (pinsulin sensitivity and/or glucose tolerance during late pregnancy. In contrast to the general view that IR is a pathological process associated with gestational diabetes, a certain degree of IR may represent an important physiological mechanism for blood glucose maintenance during fasting. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Twenty-four-hour variations in blood glucose level in Japanese type 2 diabetes patients based on continuous glucose monitoring.

    Science.gov (United States)

    Hajime, Maiko; Okada, Yosuke; Mori, Hiroko; Otsuka, Takashi; Kawaguchi, Mayuko; Miyazaki, Megumi; Kuno, Fumi; Sugai, Kei; Sonoda, Satomi; Tanaka, Kenichi; Kurozumi, Akira; Narisawa, Manabu; Torimoto, Keiichi; Arao, Tadashi; Tanaka, Yoshiya

    2018-01-01

    High fluctuations in blood glucose are associated with various complications. The correlation between glycated hemoglobin (HbA1c) level and fluctuations in blood glucose level has not been studied in Japanese patients with type 2 diabetes. In the present study, blood glucose profile stratified by HbA1c level was evaluated by continuous glucose monitoring (CGM) in Japanese type 2 diabetes patients. Our retrospective study included 294 patients with type 2 diabetes who were divided by HbA1c level into five groups (≥6.0 to level and CGM data was analyzed. The primary end-point was the difference in blood glucose fluctuations among the HbA1c groups. The mean blood glucose level increased significantly with increasing HbA1c (P trend  levels of maximum blood glucose, minimum blood glucose, each preprandial blood glucose, each postprandial maximum blood glucose, range of increase in postprandial glucose from pre-meal to after breakfast, the area under the blood concentration-time curve >180 mg/dL and percentage of the area under the blood concentration-time curve >180 mg/dL were higher with higher HbA1c. Mean glucose level and pre-breakfast blood glucose level were significant and independent determinants of HbA1c. In Japanese patients treated for type 2 diabetes, the mean amplitude of glycemic excursions did not correlate with HbA1c, making it difficult to assess blood glucose fluctuations using HbA1c. Parameters other than HbA1c are required to evaluate fluctuations in blood glucose level in patients receiving treatment for type 2 diabetes. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

  13. Glucose screening tests during pregnancy

    Science.gov (United States)

    Oral glucose tolerance test - pregnancy; OGTT - pregnancy; Glucose challenge test - pregnancy; Gestational diabetes - glucose screening ... screening test between 24 and 28 weeks of pregnancy. The test may be done earlier if you ...

  14. Bisphenol A, phthalate metabolites and glucose homeostasis in healthy normal-weight children

    DEFF Research Database (Denmark)

    Carlsson, Amalie; Sørensen, Kaspar; Andersson, Anna-Maria

    2018-01-01

    . RESULTS: Children in the lowest tertile of urinary BPA had significantly higher peak insulin levels during OGTT (P = 0.01), lower insulin sensitivity index (P triglyceride (P ... toward higher fat mass index (P = 0.1) compared with children in the highest tertile for uBPA. No significant differences in anthropometrics, body composition or glucose metabolism were associated with any of the phthalate metabolites measured. CONCLUSION: This pilot study on healthy normal...... and adolescents. METHOD: This was a cross-sectional study. Participants were recruited as part of the Copenhagen Puberty Study. The subjects were evaluated by an oral glucose tolerance test (OGTT), a dual-energy X-ray absorptiometry (DXA) scan, direct oxygen uptake measurement during cycle ergometry and fasting...

  15. Impaired Glucose Metabolism Despite Decreased Insulin Resistance After Renal Transplantation

    Directory of Open Access Journals (Sweden)

    Manfred Hecking

    2012-06-01

    Full Text Available The pathophysiology underlying new-onset diabetes after transplantation (NODAT is unresolved. We obtained demographics and laboratory data from all 1064 renal transplant recipients followed at our outpatient clinic in 2009/2010, randomly assigned 307 patients without previously diagnosed diabetes to a routine 2-hour oral glucose tolerance test (OGTT, and compared the metabolic results to a large, unrelated cross-sectional cohort of non-transplanted subjects. Among renal transplant recipients, 11% had a history of NODAT, and 12% had type 1 and type 2 diabetes. 42% of all OGTTs were abnormal (9% diabetic, predominantly in older patients who received tacrolimus. Compared to non-transplanted subjects, basal glucose was lower and HbA1c higher in renal transplant patients. Compared to non-transplanted subjects, insulin secretion was inferior, and insulin sensitivity improved at ≥6 months, as well as 3 months post-transplantation:(The Figure shows linear spline interpolation; all p for overall difference between non-Tx and Tx patients <0.02, using likelihood ratio testing. Our results indicate that impaired insulin secretion is the predominant problem after renal transplantation, suggesting benefit for therapeutic regimens that preserve beta cell function after renal transplantation. The mechanism of increased insulin sensitivity might be pathophysiologically similar to pancreatogenic diabetes.fx1

  16. [A comparison of post-surgical plasma glucose levels in patients on fluids with different glucose concentrations].

    Science.gov (United States)

    Martínez Carapeto, Isabel; López Castilla, José Domingo; Fresneda Gutiérrez, Reyes

    2017-11-11

    To compare plasma glucose levels and incidence of hyperglycaemia in the post-operative period after general surgery using fluids with different glucose. A randomised, open-label, non-blind, clinical trial was conducted on patients admitted to Paediatric Intensive Care Unit after elective surgery. The inclusion criteria were from 6 months to 14 years of age, with a weight greater than 6kg, onset glucose level >60mg/dL, and a signed informed consent, with no oral intake and maintenance intravenous fluid therapy using fluids with 3.3% or 5% glucose. Plasma glucose levels were measured before surgery, on admission, and 8, 24, and 48h, with the mean glucose levels and incidence of hyperglycaemia (glucose level >150mg/dL) in both groups being compared. A total of 60 patients received glucose/saline 1/3 (51mEq/L sodium and 33g/L glucose), and 70 glucose/saline 5/0.9% (154mEq/L sodium and 50g/L glucose). Mean glucose levels were higher in the group receiving glucose 5%, with no statistical difference. There was no significant difference in the incidence of hyperglycaemia; 8h: 26% in the 3.3% group vs. 21.3% in the 5% group (P=.63); 24h: 20% vs. 22.7% (P=.8); and 48h: 19% vs. 23.1% (P=.78). The use of fluids with 3.3% glucose in the post-operative period of general surgery maintains mean glucose levels in a similar range to that of patients receiving fluids with 5% glucose, with no difference in the incidence of hyperglycaemia. Copyright © 2017. Publicado por Elsevier España, S.L.U.

  17. Shikonin increases glucose uptake in skeletal muscle cells and improves plasma glucose levels in diabetic Goto-Kakizaki rats.

    Directory of Open Access Journals (Sweden)

    Anette I Öberg

    Full Text Available BACKGROUND: There is considerable interest in identifying compounds that can improve glucose homeostasis. Skeletal muscle, due to its large mass, is the principal organ for glucose disposal in the body and we have investigated here if shikonin, a naphthoquinone derived from the Chinese plant Lithospermum erythrorhizon, increases glucose uptake in skeletal muscle cells. METHODOLOGY/PRINCIPAL FINDINGS: Shikonin increases glucose uptake in L6 skeletal muscle myotubes, but does not phosphorylate Akt, indicating that in skeletal muscle cells its effect is medaited via a pathway distinct from that used for insulin-stimulated uptake. Furthermore we find no evidence for the involvement of AMP-activated protein kinase in shikonin induced glucose uptake. Shikonin increases the intracellular levels of calcium in these cells and this increase is necessary for shikonin-mediated glucose uptake. Furthermore, we found that shikonin stimulated the translocation of GLUT4 from intracellular vesicles to the cell surface in L6 myoblasts. The beneficial effect of shikonin on glucose uptake was investigated in vivo by measuring plasma glucose levels and insulin sensitivity in spontaneously diabetic Goto-Kakizaki rats. Treatment with shikonin (10 mg/kg intraperitoneally once daily for 4 days significantly decreased plasma glucose levels. In an insulin sensitivity test (s.c. injection of 0.5 U/kg insulin, plasma glucose levels were significantly lower in the shikonin-treated rats. In conclusion, shikonin increases glucose uptake in muscle cells via an insulin-independent pathway dependent on calcium. CONCLUSIONS/SIGNIFICANCE: Shikonin increases glucose uptake in skeletal muscle cells via an insulin-independent pathway dependent on calcium. The beneficial effects of shikonin on glucose metabolism, both in vitro and in vivo, show that the compound possesses properties that make it of considerable interest for developing novel treatment of type 2 diabetes.

  18. Precision and accuracy of blood glucose measurements using three different instruments.

    Science.gov (United States)

    Nowotny, B; Nowotny, P J; Strassburger, K; Roden, M

    2012-02-01

    Assessment of insulin sensitivity by dynamic metabolic tests such as the hyperinsulinemic euglycemic clamp critically relies on the reproducible and fast measurement of blood glucose concentrations. Although various instruments have been developed over the last decades, little is known as to the accuracy and comparability. We therefore compared the best new instrument with the former gold standard instruments to measure glucose concentrations in metabolic tests. Fasting blood samples of 15 diabetic and 10 healthy subjects were collected into sodium-fluoride tubes, spiked with glucose (0, 2.8, 6.9 and 11.1 mmol/l) and measured either as whole blood (range 3.3-26.3 mmol/l) or following centrifugation as plasma (range 3.9-32.0 mmol/l). Plasma samples were analyzed in the YSI-2300 STAT plus (YSI), EKF Biosen C-Line (EKF) and the reference method, Beckman Glucose analyzer-II (BMG), whole blood samples in EKF instruments with YSI as reference method. The average deviation of the EKF from the reference, BMG, was 3.0 ± 3.5% without any concentration-dependent variability. Glucose measurements by YSI were in good agreement with that by BMG (plasma) and EKF (plasma and whole blood) up to concentrations of 13.13 mmol/l (0.5 ± 3.7%), but deviation increased to -6.2 ± 3.8% at higher concentrations. Precision (n = 6) was ±2.2% (YSI), ±3.9% (EKF) and ±5.2% (BMG). The EKF instrument is comparable regarding accuracy and precision to the reference method BMG and can be used in metabolic tests, while the YSI showed a systematic shift at higher glucose concentrations. Based on these results we decided to replace BMG with EKF instrument in metabolic tests. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

  19. Serum Insulin, Glucose, Indices of Insulin Resistance, and Risk of Lung Cancer.

    Science.gov (United States)

    Argirion, Ilona; Weinstein, Stephanie J; Männistö, Satu; Albanes, Demetrius; Mondul, Alison M

    2017-10-01

    Background: Although insulin may increase the risk of some cancers, few studies have examined fasting serum insulin and lung cancer risk. Methods: We examined serum insulin, glucose, and indices of insulin resistance [insulin:glucose molar ratio and homeostasis model assessment of insulin resistance (HOMA-IR)] and lung cancer risk using a case-cohort study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of Finnish men. A total of 196 cases and 395 subcohort members were included. Insulin and glucose were measured in fasting serum collected 5 to 12 years before diagnosis. Cox proportional hazards models were utilized to estimate the relative risk of lung cancer. Results: The average time between blood collection and lung cancer was 9.6 years. Fasting serum insulin levels were 8.7% higher in subcohort members than cases. After multivariable adjustment, men in the fourth quartile of insulin had a significantly higher risk of lung cancer than those in the first quartile [HR = 2.10; 95% confidence interval (CI), 1.12-3.94]. A similar relationship was seen with HOMA-IR (HR = 1.83; 95% CI, 0.99-3.38). Risk was not strongly associated with glucose or the insulin:glucose molar ratio ( P trend = 0.55 and P trend = 0.27, respectively). Conclusions: Higher fasting serum insulin concentrations, as well as the presence of insulin resistance, appear to be associated with an elevated risk of lung cancer development. Impact: Although insulin is hypothesized to increase risk of some cancers, insulin and lung cancer remain understudied. Higher insulin levels and insulin resistance were associated with increased lung cancer risk. Although smoking cessation is the best method of lung cancer prevention, other lifestyle changes that affect insulin concentrations and sensitivity may reduce lung cancer risk. Cancer Epidemiol Biomarkers Prev; 26(10); 1519-24. ©2017 AACR . ©2017 American Association for Cancer Research.

  20. Synthesis of redox polymer nanobeads and nanocomposites for glucose biosensors.

    Science.gov (United States)

    Wang, Jen-Yuan; Chen, Lin-Chi; Ho, Kuo-Chuan

    2013-08-28

    Redox polymer nanobeads of branched polyethylenimine binding with ferrocene (BPEI-Fc) were synthesized using a simple chemical process. The functionality and morphology of the redox polymer nanobeads were investigated by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). This hydrophilic redox nanomaterial could be mixed with glucose oxidase (GOx) for drop-coating on a screen-printed carbon electrode (SPCE) for glucose sensing application. Electrochemical properties of the BPEI-Fc/GOx/SPCE prepared under different conditions were studied by cyclic voltammetry (CV). On the basis of these CV results, the synthetic condition of the BPEI-Fc/GOx/SPCE could be optimized. By incorporating conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), the performance of a redox polymer nanobead–based enzyme electrode could be further improved. The influence of PEDOT:PSS on the nanocomposite enzyme electrode was discussed from the aspects of the apparent electron diffusion coefficient (D(app)) and the charge transfer resistance (R(ct)). The glucose-sensing sensitivity of the BPEI-Fc/PEDOT:PSS/GOx/SPCE is calculated to be 66 μA mM(–1) cm(–2), which is 2.5 times higher than that without PEDOT:PSS. The apparent Michaelis constant (K(M)(app)) of the BPEI-Fc/PEDOT:PSS/GOx/SPCE estimated by the Lineweaver–Burk plot is 2.4 mM, which is much lower than that of BPEI-Fc/GOx/SPCE (11.2 mM). This implies that the BPEI-Fc/PEDOT:PSS/GOx/SPCE can catalytically oxidize glucose in a more efficient way. The interference test was carried out by injection of glucose and three common interferences: ascorbic acid (AA), dopamine (DA), and uric acid (UA) at physiological levels. The interferences of DA (4.2%) and AA (7.8%) are acceptable and the current response to UA (1.6%) is negligible, compared to the current response to glucose.

  1. Wearable Contact Lens Biosensors for Continuous Glucose Monitoring Using Smartphones.

    Science.gov (United States)

    Elsherif, Mohamed; Hassan, Mohammed Umair; Yetisen, Ali K; Butt, Haider

    2018-05-17

    Low-cost, robust, and reusable continuous glucose monitoring systems that can provide quantitative measurements at point-of-care settings is an unmet medical need. Optical glucose sensors require complex and time-consuming fabrication processes, and their readouts are not practical for quantitative analyses. Here, a wearable contact lens optical sensor was created for the continuous quantification of glucose at physiological conditions, simplifying the fabrication process and facilitating smartphone readouts. A photonic microstructure having a periodicity of 1.6 μm was printed on a glucose-selective hydrogel film functionalized with phenylboronic acid. Upon binding with glucose, the microstructure volume swelled, which modulated the periodicity constant. The resulting change in the Bragg diffraction modulated the space between zero- and first-order spots. A correlation was established between the periodicity constant and glucose concentration within 0-50 mM. The sensitivity of the sensor was 12 nm mM -1 , and the saturation response time was less than 30 min. The sensor was integrated with commercial contact lenses and utilized for continuous glucose monitoring using smartphone camera readouts. The reflected power of the first-order diffraction was measured via a smartphone application and correlated to the glucose concentrations. A short response time of 3 s and a saturation time of 4 min was achieved in the continuous monitoring mode. Glucose-sensitive photonic microstructures may have applications in point-of-care continuous monitoring devices and diagnostics at home settings.

  2. Design of nanostructured-based glucose biosensors

    Science.gov (United States)

    Komirisetty, Archana; Williams, Frances; Pradhan, Aswini; Konda, Rajini B.; Dondapati, Hareesh; Samantaray, Diptirani

    2012-04-01

    This paper presents the design of glucose sensors that will be integrated with advanced nano-materials, bio-coatings and electronics to create novel devices that are highly sensitive, inexpensive, accurate, and reliable. In the work presented, a glucose biosensor and its fabrication process flow have been designed. The device is based on electrochemical sensing using a working electrode with bio-functionalized zinc oxide (ZnO) nano-rods. Among all metal oxide nanostructures, ZnO nano-materials play a significant role as a sensing element in biosensors due to their properties such as high isoelectric point (IEP), fast electron transfer, non-toxicity, biocompatibility, and chemical stability which are very crucial parameters to achieve high sensitivity. Amperometric enzyme electrodes based on glucose oxidase (GOx) are used due to their stability and high selectivity to glucose. The device also consists of silicon dioxide and titanium layers as well as platinum working and counter electrodes and a silver/silver chloride reference electrode. Currently, the biosensors are being fabricated using the process flow developed. Once completed, the sensors will be bio-functionalized and tested to characterize their performance, including their sensitivity and stability.

  3. Carbon Nanotube Yarn-Based Glucose Sensing Artificial Muscle.

    Science.gov (United States)

    Lee, Junghan; Ko, Sachan; Kwon, Cheong Hoon; Lima, Márcio D; Baughman, Ray H; Kim, Seon Jeong

    2016-04-01

    Boronic acid (BA), known to be a reversible glucose-sensing material, is conjugated to a nanogel (NG) derived from hyaluronic acid biopolymer and used as a guest material for a carbon multiwalled nanotube (MWNT) yarn. By exploiting the swelling/deswelling of the NG that originates from the internal anionic charge changes resulting from BA binding to glucose, a NG MWNT yarn artificial muscle is obtained that provides reversible torsional actuation that can be used for glucose sensing. This actuator shows a short response time and high sensitivity (in the 5-100 × 10(-3) m range) for monitoring changes in glucose concentration in physiological buffer, without using any additional auxiliary substances or an electrical power source. It may be possible to apply the glucose-sensing MWNT yarn muscles as implantable glucose sensors that automatically release drugs when needed or as an artificial pancreas. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Glucose biosensor based on glucose oxidase immobilized on unhybridized titanium dioxide nanotube arrays

    International Nuclear Information System (INIS)

    Wang, Wei; Xie, Yibing; Du, Hongxiu; Xia, Chi; Wang, Yong; Tian, Fang

    2014-01-01

    A glucose biosensor has been fabricated by immobilizing glucose oxidase (GOx) on unhybridized titanium dioxide nanotube arrays using an optimized cross-linking technique. The TiO 2 nanotube arrays were synthesized directly on a titanium substrate by anodic oxidation. The structure and morphology of electrode material were characterized by X-ray diffraction and scanning electron microscopy. The electrochemical performances of the glucose biosensor were conducted by cyclic voltammetry and chronoamperometry measurements. It gives a linear response to glucose in the 0.05 to 0.65 mM concentration range, with a correlation coefficient of 0.9981, a sensitivity of 199.6 μA mM −1 cm −2 , and a detection limit as low as 3.8 µM. This glucose biosensor exhibited high selectivity for glucose determination in the presence of ascorbic acid, sucrose and other common interfering substances. This glucose biosensor also performed good reproducibility and long-time storage stability. This optimized cross-linking technique could open a new avenue for other enzyme biosensors fabrication. (author)

  5. Hyperglycemia (High Blood Glucose)

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  12. Nocturnal continuous glucose monitoring

    DEFF Research Database (Denmark)

    Bay, Christiane; Kristensen, Peter Lommer; Pedersen-Bjergaard, Ulrik

    2013-01-01

    Abstract Background: A reliable method to detect biochemical nocturnal hypoglycemia is highly needed, especially in patients with recurrent severe hypoglycemia. We evaluated reliability of nocturnal continuous glucose monitoring (CGM) in patients with type 1 diabetes at high risk of severe...

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  12. Glucosensing in the gastrointestinal tract: Impact on glucose metabolism

    Science.gov (United States)

    Fournel, Audren; Marlin, Alysson; Abot, Anne; Pasquio, Charles; Cirillo, Carla; Cani, Patrice D.

    2016-01-01

    The gastrointestinal tract is an important interface of exchange between ingested food and the body. Glucose is one of the major dietary sources of energy. All along the gastrointestinal tube, e.g., the oral cavity, small intestine, pancreas, and portal vein, specialized cells referred to as glucosensors detect variations in glucose levels. In response to this glucose detection, these cells send hormonal and neuronal messages to tissues involved in glucose metabolism to regulate glycemia. The gastrointestinal tract continuously communicates with the brain, especially with the hypothalamus, via the gut-brain axis. It is now well established that the cross talk between the gut and the brain is of crucial importance in the control of glucose homeostasis. In addition to receiving glucosensing information from the gut, the hypothalamus may also directly sense glucose. Indeed, the hypothalamus contains glucose-sensitive cells that regulate glucose homeostasis by sending signals to peripheral tissues via the autonomous nervous system. This review summarizes the mechanisms by which glucosensors along the gastrointestinal tract detect glucose, as well as the results of such detection in the whole body, including the hypothalamus. We also highlight how disturbances in the glucosensing process may lead to metabolic disorders such as type 2 diabetes. A better understanding of the pathways regulating glucose homeostasis will further facilitate the development of novel therapeutic strategies for the treatment of metabolic diseases. PMID:26939867

  13. Glucosensing in the gastrointestinal tract: Impact on glucose metabolism.

    Science.gov (United States)

    Fournel, Audren; Marlin, Alysson; Abot, Anne; Pasquio, Charles; Cirillo, Carla; Cani, Patrice D; Knauf, Claude

    2016-05-01

    The gastrointestinal tract is an important interface of exchange between ingested food and the body. Glucose is one of the major dietary sources of energy. All along the gastrointestinal tube, e.g., the oral cavity, small intestine, pancreas, and portal vein, specialized cells referred to as glucosensors detect variations in glucose levels. In response to this glucose detection, these cells send hormonal and neuronal messages to tissues involved in glucose metabolism to regulate glycemia. The gastrointestinal tract continuously communicates with the brain, especially with the hypothalamus, via the gut-brain axis. It is now well established that the cross talk between the gut and the brain is of crucial importance in the control of glucose homeostasis. In addition to receiving glucosensing information from the gut, the hypothalamus may also directly sense glucose. Indeed, the hypothalamus contains glucose-sensitive cells that regulate glucose homeostasis by sending signals to peripheral tissues via the autonomous nervous system. This review summarizes the mechanisms by which glucosensors along the gastrointestinal tract detect glucose, as well as the results of such detection in the whole body, including the hypothalamus. We also highlight how disturbances in the glucosensing process may lead to metabolic disorders such as type 2 diabetes. A better understanding of the pathways regulating glucose homeostasis will further facilitate the development of novel therapeutic strategies for the treatment of metabolic diseases. Copyright © 2016 the American Physiological Society.

  14. [Glucose-monitoring neurons of the medial ventrolateral prefrontal (orbitofrontal) cortex are involved in the maintenance of homeostasis].

    Science.gov (United States)

    Szabó, István; Hormay, Edina; Csetényi, Bettina; Nagy, Bernadett; Karádi, Zoltán

    2017-05-01

    The medial orbitofrontal cortex is involved in the regulation of feeding and metabolism. Little is known, however, about the role of local glucose-monitoring neurons in these processes, and our knowledge is also poor about characteristics of these cells. The functional significance of these chemosensory neurons was to be elucidated. Electrophysiology, by the multibarreled microelectrophoretic technique, and metabolic investigations, after streptozotocin induced selective destruction of the chemosensory neurons, were employed. Fifteen percent of the neurons responded to glucose, and these chemosensory cells displayed differential neurotransmitter and taste sensitivities. In acute glucose tolerance test, at the 30th and 60th minutes, blood glucose level in the streptozotocin-treated rats was significantly higher than that in the controls. The plasma triglyceride concentrations were also higher in the streptozotocin-treated group. Glucose-monitoring neurons of the medial orbitofrontal cortex integrate internal and external environmental signals, and monitor metabolic processes, thus, are indispensable to maintain the healthy homeostasis. Orv Hetil. 2017; 158(18): 692-700.

  15. suPAR associates to glucose metabolic aberration during glucose stimulation in HIV-infected patients on HAART

    DEFF Research Database (Denmark)

    Andersen, Ove; Eugen-Olsen, Jesper; Kofoed, Kristian

    2008-01-01

    extend these findings by investigating the association of suPAR to glucose metabolic insufficiency during an oral glucose challenge (OGTT). METHODS: In 16 HIV-infected patients with lipodystrophy and 15 HIV-infected patients without lipodystrophy, glucose tolerance, insulin sensitivity (ISI......PAR correlated inversely with ISI(composite) and positively with 2h plasma glucose, fasting insulin secretion, fasting intact proinsulin and FFA level during the OGTT (all P...-RNA, duration of HIV infection), and dyslipidemia (plasma total cholesterol, triglyceride and free fatty acid level during the OGTT) were included, suPAR remained a significant marker of glucose tolerance and insulin sensitivity. Plasma suPAR exhibited a small CV (11%) during the 3h OGTT. CONCLUSIONS: su...

  16. Salivary glucose concentration and excretion in normal and diabetic subjects.

    Science.gov (United States)

    Jurysta, Cedric; Bulur, Nurdan; Oguzhan, Berrin; Satman, Ilhan; Yilmaz, Temel M; Malaisse, Willy J; Sener, Abdullah

    2009-01-01

    The present report aims mainly at a reevaluation of salivary glucose concentration and excretion in unstimulated and mechanically stimulated saliva in both normal and diabetic subjects. In normal subjects, a decrease in saliva glucose concentration, an increase in salivary flow, but an unchanged glucose excretion rate were recorded when comparing stimulated saliva to unstimulated saliva. In diabetic patients, an increase in salivary flow with unchanged salivary glucose concentration and glucose excretion rate were observed under the same experimental conditions. Salivary glucose concentration and excretion were much higher in diabetic patients than in control subjects, whether in unstimulated or stimulated saliva. No significant correlation between glycemia and either glucose concentration or glucose excretion rate was found in the diabetic patients, whether in unstimulated or stimulated saliva. In the latter patients, as compared to control subjects, the relative magnitude of the increase in saliva glucose concentration was comparable, however, to that of blood glucose concentration. The relationship between these two variables was also documented in normal subjects and diabetic patients undergoing an oral glucose tolerance test.

  17. SCAPIS Pilot Study: Sitness, Fitness and Fatness - Is Sedentary Time Substitution by Physical Activity Equally Important for Everyone's Markers of Glucose Regulation?

    Science.gov (United States)

    Ekblom-Bak, Elin; Ekblom, Örjan; Bolam, Kate A; Ekblom, Björn; Bergström, Göran; Börjesson, Mats

    2016-07-01

    Although moderate-to-vigorous physical activity (MVPA) is mainly recommended for glucose control, light physical activity (LIPA) may also have the potential to induce favorable changes. We investigated sedentary time (SED) substitution with equal time in LIPA and MVPA, and the association with markers of glucose regulation and insulin sensitivity after stratification by waist circumference, fitness and fasting glucose levels. A total of 654 men and women, 50 to 64 years, from the SCAPIS pilot study were included. Daily SED, LIPA and MVPA were assessed using hip-worn accelerometers. Fasting plasma glucose, insulin and HOMA-IR were determined. Substituting 30 min of SED with LIPA was significantly associated with 3.0% lower fasting insulin values and 3.1% lower HOMA-IR values, with even lower levels when substituting SED with MVPA. Participants with lower fitness and participants with high fasting glucose levels benefited significantly more from substituting 30 min of SED with LIPA compared with participants with normal to high fitness levels and participants with normal glucose levels, respectively. LIPA, and not only MVPA, may have beneficial associations with glucose regulation. This is of great clinical and public health importance, not least because it may confer a higher compliance rate to regular PA.

  18. Roles of glucose in photoreceptor survival.

    Science.gov (United States)

    Chertov, Andrei O; Holzhausen, Lars; Kuok, Iok Teng; Couron, Drew; Parker, Ed; Linton, Jonathan D; Sadilek, Martin; Sweet, Ian R; Hurley, James B

    2011-10-07

    Vertebrate photoreceptor neurons have a high demand for metabolic energy, and their viability is very sensitive to genetic and environmental perturbations. We investigated the relationship between energy metabolism and cell death by evaluating the metabolic effects of glucose deprivation on mouse photoreceptors. Oxygen consumption, lactate production, ATP, NADH/NAD(+), TCA cycle intermediates, morphological changes, autophagy, and viability were evaluated. We compared retinas incubated with glucose to retinas deprived of glucose or retinas treated with a mixture of mitochondrion-specific fuels. Rapid and slow phases of cell death were identified. The rapid phase is linked to reduced mitochondrial activity, and the slower phase reflects a need for substrates for cell maintenance and repair.

  19. The effects of glucose ingestion and glucose regulation on memory performance in older adults with mild cognitive impairment.

    Science.gov (United States)

    Riby, L M; Marriott, A; Bullock, R; Hancock, J; Smallwood, J; McLaughlin, J

    2009-04-01

    Previous research investigating the impact of glucose ingestion and/or improvements in glucose regulation has found selective cognitive facilitation on episodic memory tasks in successful ageing and dementia. The present study aimed to extend this research to mild cognitive impairment (MCI). In a repeated-measures design, 24 older adults with and 24 older adults without MCI performed a battery of memory and attention tasks after 25 g of glucose or a sweetness matched placebo. In addition, to assess the impact of individual differences in glucose regulation, blood glucose measurements were taken throughout the testing session. Consistent with previous research, cognitive facilitation was observed for episodic memory tasks only in both successful ageing and MCI. Older adults with MCI had a similar glucose regulatory response as controls but their fasting levels were elevated. Notably, higher levels of blood glucose were associated with impaired memory performance in both the glucose and placebo conditions. Importantly, both blood glucose and memory performance indices were significant predictors of MCI status. The utility of glucose supplementation and the use of glucose regulation as a biological marker are discussed in relation to these data.

  20. Higher insulin sensitivity in EDL muscle of rats fed a low-protein, high-carbohydrate diet inhibits the caspase-3 and ubiquitin-proteasome proteolytic systems but does not increase protein synthesis.

    Science.gov (United States)

    Dos Santos, Maísa Pavani; Batistela, Emanuele; Pereira, Mayara Peron; Paula-Gomes, Silvia; Zanon, Neusa Maria; Kettelhut, Isis do Carmo; Karatzaferi, Christina; Andrade, Claudia Marlise Balbinotti; de França, Suélem Aparecida; Baviera, Amanda Martins; Kawashita, Nair Honda

    2016-08-01

    Compared with the extensor digitorum longus (EDL) muscle of control rats (C), the EDL muscle of rats fed a low-protein, high-carbohydrate diet (LPHC) showed a 36% reduction in mass. Muscle mass is determined by the balance between protein synthesis and proteolysis; thus, the aim of this work was to evaluate the components involved in these processes. Compared with the muscle from C rats, the EDL muscle from LPHC diet-fed rats showed a reduction (34%) in the in vitro basal protein synthesis and a 22% reduction in the in vitro basal proteolysis suggesting that the reduction in the mass can be associated with a change in the rate of the two processes. Soon after euthanasia, in the EDL muscles of the rats fed the LPHC diet for 15days, the activity of caspase-3 and that of components of the ubiquitin-proteasome system (atrogin-1 content and chymotrypsin-like activity) were decreased. The phosphorylation of p70(S6K) and 4E-BP1, proteins involved in protein synthesis, was also decreased. We observed an increase in the insulin-stimulated protein content of p-Akt. Thus, the higher insulin sensitivity in the EDL muscle of LPHC rats seemed to contribute to the lower proteolysis in LPHC rats. However, even with the higher insulin sensitivity, the reduction in p-E4-BP1 and p70(S6K) indicates a reduction in protein synthesis, showing that factors other than insulin can have a greater effect on the control of protein synthesis. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. THE CHALLENGE OF PD PATIENTS: GLUCOSE AND GLUCOSE DEGRADATION PRODUCTS IN PD SOLUTION

    Directory of Open Access Journals (Sweden)

    Yong-Lim Kim

    2012-06-01

    Full Text Available The main osmotic agent found in the peritoneal dialysis (PD solution is glucose. It has been of a wide use for great crystalloid osmotic power at a low concentration, simple metabolism, and excellent safety. On the other hand, anywhere between 60 to 80% of the glucose in the PD solution is absorbed - a 100 to 300 mg of daily glucose absorption. Once into the systemic circulation, glucose can be a cause for metabolic complications including obesity. Indeed, the diabetiform change observed in the peritoneal membrane in the long-term PD patients is believed attributable to the high-concentration glucose in the PD solution. The glucose absorbed from peritoneal cavity raises the risk of ‘glucose toxicity’, leading to insulin resistance and beta cell failure. Clinical similarity can be found in postprandial hyperglycemia, which is known to be associated with oxidative stress, endothelial dysfunction, NF-κb, and inflammation, affecting myocardial blood flow. Moreover, it is a proven independent risk factor of coronary artery disease in patients with type 2 diabetes, particularly of female gender. Though speculative yet, glucose toxicity might explain a higher mortality of PD patients after the first year compared with those on hemodialysis (more so in female, advanced-age patients with diabetes. Also included in the picture are glucose degradation products (GDPs generated along the course of heat sterilization or storage of the PD solution. They have been shown to induce apoptosis of peritoneal mesothelial cells, renal tubular epithelial cells, and endothelial cells, while spurring production of TGF-β and VEGF and facilitating epithelial mesenchymal transition. GDPs provide a stronger reactivity than glucose in the formation of AGEs, a known cause for microvascular complications and arteriosclerosis. Unfortunately, clinical studies using a low-GDP PD solution have provided mixed results on the residual renal function, peritonitis, peritoneal

  2. Insulin resistance and lipid profile during an oral glucose tolerance test in women with and without gestational diabetes mellitus.

    Science.gov (United States)

    Liang, Zx; Wu, Y; Zhu, Xy; Fang, Q; Chen, Dq

    2016-01-01

    We aimed to compare changes in insulin levels during an oral glucose tolerance test (OGTT) between women with normal glucose tolerance (NGT) during pregnancy and those with gestational diabetes mellitus (GDM). Overall, 105 pregnant women between 24 and 28 weeks' gestation, 50 with NGT and 55 with GDM according to NDDG standard, were enrolled into the study. The levels of fasting blood glucose, insulin, triglyceride (TG) and total cholesterol (TC) and the insulin levels, blood glucose levels at 1, 2 and 3 hours post oral glucose administration during an OGTT (5.8, 10.6, 9.2 and 8.1 mmol/L, respectively) were measured. Then, insulin resistance (IR) index was calculated. There was no significant difference in fasting, 3-h insulin levels and 3-h blood glucose levels between those with NGT and those with GDM (P > 0.05). However, 1-h and 2-h insulin levels, fasting and 1-h and 2-h blood glucose levels in women with GDM were significantly higher than those in the NGT group (P < 0.05). Fasting TC and TG levels in the GDM group were significantly higher than those with NGT (P = 0.031 and P = 0.025, respectively). Correlation analysis showed that TG and TC levels were positively correlated with homoeostasis model assessment-IR (HOMA-IR) (r = 0.67 and r = 0.78, respectively; P < 0.05). Our findings suggest that insulin sensitivity in women with GDM was significantly lower than that observed in those with NGT. Reducing IR and blood lipids in women with GDM could potentially improve maternal and foetal outcomes.

  3. Glucose effects on long-term memory performance : duration and domain specificity.

    OpenAIRE

    Owen, Laura; Finnegan, Yvonne; Hu, Henglong; Scholey, Andrew B.; Sünram-Lea, Sandra I.

    2010-01-01

    Rational; Previous research has suggested that long term- verbal declarative memory is particularly sensitive to enhancement by glucose loading, however investigation of glucose effects on certain memory domains has hitherto been neglected. Therefore domain specificity of glucose effects merits further elucidation. Objectives; The aim of the present research was to provide a more comprehensive investigation of the possible effects of glucose administration on different aspects of memory by i)...

  4. Noninvasive measurement of blood glucose level using mid-infrared quantum cascade lasers

    Science.gov (United States)

    Yoshioka, Kiriko; Kino, Saiko; Matsuura, Yuji

    2017-04-01

    For non-invasive measurement of blood glucose level, attenuated total reflection (ATR) absorption spectroscopy system using a QCL as a light source was developed. The results of measurement of glucose solutions showed that the system had a sensitivity that was enough for blood glucose measurement. In-vivo measurement using the proposed system based on QCL showed that there was a correlation between absorptions measured with human lips and blood glucose level.

  5. Spatial relationship between tumor perfusion and endogeneous glucose distribution

    International Nuclear Information System (INIS)

    Schroeder, T.; Larrier, N.; Viglianti, B.; Rabbani, Z.N.; Peltz, C.; Vujascovic, Z.; Dewhirst, M.W.

    2003-01-01

    Earlier studies detecting glucose in tissue and solid tumors by bioluminescence imaging suggested, that glucose distribution patterns may be spatially related to functional vascularity. The purpose of this study was to evaluate this relationship by comparing glucose distribution patterns as determined by bioluminescence imaging to perfusion patterns of endogeneous Hoechst 33342 in rats bearing mammary carcinomas. R 3230 mammary carcinoma cells have been implanted subcutaneously into 7 female Fischer 344 rats. Two months post implantation, after injection of Hoechst 33342 the tumors were removed and snap frozen to conserve metabolite levels. Concomitantly, blood was sampled from the animals for analysis of glucose concentrations using a micodialysis analyzer. Cryosections of the tumors have been prepared, and every slice has been analyzed for both, Hoechst binding by fluorescence microscopy, and for glucose distribution patterns using bioluminescence imaging. In many cases vascular structures could be retrieved by the spatial pattern of glucose distribution. In some cases however, higher glucose concentrations could be found independent from Hoechst signal. On the other hand, regions of high Hoechst signal are not necessarily correlated with high glucose concentrations. When comparing blood and tissue glucose levels, tissue glucose content as measured with bioluminescence imaging (1.9-3.5 mM) is considerably lower than blood glucose (5.6-8.0 mM), demonstrating the expected gradient from blood to tissue. This study demonstrates the feasibility of monitoring glucose gradients in relation to functional vasculature throughout the body, from blood down to tissue or tumor and further, throughout the microenvironment of the solid tumor. Glucose distribution patterns may be an important tool in perfusion studies, e. g. in detecting the direction of blood flow in ex-vivo samples or in estimating glucose consumption rates of tumor cells adjacent to or in between perfused

  6. Sex steroids and glucose metabolism

    Directory of Open Access Journals (Sweden)

    Carolyn A Allan

    2014-04-01

    Full Text Available Testosterone levels are lower in men with metabolic syndrome and type 2 diabetes mellitus (T2DM and also predict the onset of these adverse metabolic states. Body composition (body mass index, waist circumference is an important mediator of this relationship. Sex hormone binding globulin is also inversely associated with insulin resistance and T2DM but the data regarding estrogen are inconsistent. Clinical models of androgen deficiency including Klinefelter's syndrome and androgen deprivation therapy in the treatment of advanced prostate cancer confirm the association between androgens and glucose status. Experimental manipulation of the insulin/glucose milieu and suppression of endogenous testicular function suggests the relationship between androgens and insulin sensitivity is bidirectional. Androgen therapy in men without diabetes is not able to differentiate the effect on insulin resistance from that on fat mass, in particular visceral adiposity. Similarly, several small clinical studies have examined the efficacy of exogenous testosterone in men with T2DM, however, the role of androgens, independent of body composition, in modifying insulin resistance is uncertain.

  7. The prevalence ofdiabetes mellitus and impaired glucose tolerance ...

    African Journals Online (AJOL)

    adjusted body mass indices (BMIs) of diabetic (31,3 ± 1,9) and. IGT (29,7 ± 1,9) subjects were significantly higher than those ofthe group with normal glucose toler- ance (28 ± 0,5). Female subjects with all types of glucose tolerance had significantly ...

  8. Development of a nanowire based titanium needle probe sensor for glucose monitoring

    Science.gov (United States)

    Deshpande, Devesh C.

    The need for continuous monitoring of various physiological functions such as blood glucose levels, neural functions and cholesterol levels has fostered the research and development of various schemes of biosensors to sense and help control the respective function. The needs of patients for sensors with minimal discomfort, longer life and better performance have necessitated the development towards smaller and more efficient sensors. In addition, the need for higher functionality from smaller sensors has led to the development of sensors with multiple electrodes, each electrode capable of sensing a different body function. Such multi-electrode sensors need to be fabricated using micro-fabrication processes in order to achieve precise control over the size, shape and placement of the electrodes. Multielectrode sensors fabricated using silicon and polymers have been demonstrated. One physiological function that attracts widespread interest is continuous glucose monitoring in our blood, since Diabetes affects millions of people all over the world. Significant deviations of blood glucose levels from the normal levels of 4-8 mM can cause fainting, coma and damage to the eyes, kidneys, nerves and blood vessels. For chronic patients, continuous monitoring of glucose levels is essential for accurate and timely treatment. A few continuous monitoring sensors are available in the market, but they have problems and cannot replace the strip type one-time glucose monitoring systems as yet. To address this need, large scale research efforts have been targeted towards continuous monitoring. The demand for higher accuracy and sensitivity has motivated researchers to evaluate the use of nanostructures in sensing. The large surface area-to-volume ratio of such structures could enable further miniaturization and push the detection limits, potentially enabling even single molecule detection. This research involved the development of a biocompatible titanium needle probe sensor for

  9. Insulin sensitivity and albuminuria

    DEFF Research Database (Denmark)

    Pilz, Stefan; Rutters, Femke; Nijpels, Giel

    2014-01-01

    OBJECTIVE: Accumulating evidence suggests an association between insulin sensitivity and albuminuria, which, even in the normal range, is a risk factor for cardiovascular diseases. We evaluated whether insulin sensitivity is associated with albuminuria in healthy subjects. RESEARCH DESIGN...... AND METHODS: We investigated 1,415 healthy, nondiabetic participants (mean age 43.9 ± 8.3 years; 54.3% women) from the RISC (Relationship between Insulin Sensitivity and Cardiovascular Disease) study, of whom 852 participated in a follow-up examination after 3 years. At baseline, insulin sensitivity...... was assessed by hyperinsulinemic-euglycemic clamps, expressed as the M/I value. Oral glucose tolerance test-based insulin sensitivity (OGIS), homeostasis model assessment of insulin resistance (HOMA-IR), and urinary albumin-to-creatinine ratio (UACR) were determined at baseline and follow-up. RESULTS...

  10. Sexual dimorphism in hepatic, adipose tissue and peripheral tissue insulin sensitivity in obese humans

    Directory of Open Access Journals (Sweden)

    Kasper W. ter Horst

    2015-11-01

    Full Text Available Glucose and lipid metabolism differ between men and women, and women tend to have better whole-body or muscle insulin sensitivity. This may be explained, in part, by differences in sex hormones and adipose tissue distribution. Few studies have investigated gender differences in hepatic, adipose tissue and whole-body insulin sensitivity between severely obese men and women. In this study, we aimed to determine the differences in glucose metabolism between severely obese men and women using tissue-specific measurements of insulin sensitivity. Insulin sensitivity was compared between age and body mass index (BMI-matched obese men and women by a two-step euglycemic hyperinsulinemic clamp with infusion of [6,6-2H2]glucose. Basal endogenous glucose production and insulin sensitivity of the liver, adipose tissue and peripheral tissues were assessed. Liver fat content was assessed by proton magnetic resonance spectroscopy in a subset of included subjects. We included 46 obese men and women (age, 48±2 vs 46±2 years, p=0.591; BMI, 41±1 vs 41±1 kg/m2, p=0.832. There was no difference in basal endogenous glucose production (14.4±1.0 vs 15.3±0.5 µmol•kg fat-free mass-1•min-1, p=0.410, adipose tissue insulin sensitivity (insulin-mediated suppression of free fatty acids, 71.6±3.6 vs 76.1±2.6%, p=0.314 or peripheral insulin sensitivity (insulin-stimulated rate of disappearance of glucose, 26.2±2.1 vs 22.7±1.7 µmol•kg-1•min-1, p=0.211. Obese men were characterized by lower hepatic insulin sensitivity (insulin-mediated suppression of endogenous glucose production, 61.7±4.1 vs 72.8±2.5% in men vs women, resp., p=0.028. Finally, these observations could not be explained by differences in liver fat content (men vs women, 16.5±3.1 vs 16.0±2.5%, p=0.913, n=27.We conclude that obese men have lower hepatic, but comparable adipose tissue and peripheral tissue, insulin sensitivity compared to similarly obese women. Hepatic insulin resistance may

  11. Higher Education

    African Journals Online (AJOL)

    Kunle Amuwo: Higher Education Transformation: A Paradigm Shilt in South Africa? ... ty of such skills, especially at the middle management levels within the higher ... istics and virtues of differentiation and diversity. .... may be forced to close shop for lack of capacity to attract ..... necessarily lead to racial and gender equity,.

  12. Perfluorooctanoic acid exposure for 28 days affects glucose homeostasis and induces insulin hypersensitivity in mice

    Science.gov (United States)

    Yan, Shengmin; Zhang, Hongxia; Zheng, Fei; Sheng, Nan; Guo, Xuejiang; Dai, Jiayin

    2015-06-01

    Perfluoroalkyl acids (PFAAs) are widely used in many applications due to their unique physical and chemical characteristics. Because of the increasing prevalence of metabolic syndromes, including obesity, dyslipidemia and insulin resistance, concern has arisen about the roles of environmental pollutants in such diseases. Earlier epidemiologic studies showed a potential association between perfluorooctanoic acid (PFOA) and glucose metabolism, but how PFOA influences glucose homeostasis is still unknown. Here, we report on the modulation of the phosphatidylinositol 3-kinase-serine/threonine protein kinase (PI3K-AKT) signaling pathway in the livers of mice after 28 d of exposure to PFOA. Compared with normal mice, PFOA exposure significantly decreased the expression of the phosphatase and tensin homologue (PTEN) protein and affected the PI3K-AKT signaling pathway in the liver. Tolerance tests further indicated that PFOA exposure induced higher insulin sensitivity and glucose tolerance in mice. Biochemical analysis revealed that PFOA exposure reduced hepatic glycogen synthesis, which might be attributed to gluconeogenesis inhibition. The levels of several circulating proteins were altered after PFOA exposure, including proteins potentially related to diabetes and liver disease. Our results suggest that PFOA affected glucose metabolism and induced insulin hypersensitivity in mice.

  13. Analysis of blood glucose distribution characteristics in a health examination population in Chengdu (2007-2015).

    Science.gov (United States)

    Huang, Wenxia; Xu, Wangdong; Zhu, Ping; Yang, Hanwei; Su, Linchong; Tang, Huairong; Liu, Yi

    2017-12-01

    With socioeconomic growth and cultural changes in China, the level of blood glucose may have changed in recent years. This study aims to detect the blood glucose distribution characteristics with a large size of health examination population.A total of 641,311 cases (360,259 males and 281,052 females) more than 18 years old during 2007 to 2015 were recruited from the Health Examination Center at West China hospital, Sichuan University.The percentage of cases with abnormal glucose level and the mean level of glucose were significantly increased since 2007 to 2015 overall. The percentage of cases with abnormal glucose level in males was significantly higher than that in females every year, and the percentage of cases with abnormal glucose level in aged population was higher than the young population. In addition, the mean level of glucose was higher in aged population with normal level of glucose than the young population with normal level of glucose, and the mean level of glucose was higher in males with normal level of glucose than the females with normal level of glucose.The population showed an increased level of blood glucose. Some preventive action may be adopted early and more attention can be paid to them.

  14. Glucose Synthesis in a Protein-Based Artificial Photosynthesis System.

    Science.gov (United States)

    Lu, Hao; Yuan, Wenqiao; Zhou, Jack; Chong, Parkson Lee-Gau

    2015-09-01

    The objective of this study was to understand glucose synthesis of a protein-based artificial photosynthesis system affected by operating conditions, including the concentrations of reactants, reaction temperature, and illumination. Results from non-vesicle-based glyceraldehyde-3-phosphate (GAP) and glucose synthesis showed that the initial concentrations of ribulose-1,5-bisphosphate (RuBP) and adenosine triphosphate (ATP), lighting source, and temperature significantly affected glucose synthesis. Higher initial concentrations of RuBP and ATP significantly enhanced GAP synthesis, which was linearly correlated to glucose synthesis, confirming the proper functions of all catalyzing enzymes in the system. White fluorescent light inhibited artificial photosynthesis and reduced glucose synthesis by 79.2 % compared to in the dark. The reaction temperature of 40 °C was optimum, whereas lower or higher temperature reduced glucose synthesis. Glucose synthesis in the vesicle-based artificial photosynthesis system reconstituted with bacteriorhodopsin, F 0 F 1 ATP synthase, and polydimethylsiloxane-methyloxazoline-polydimethylsiloxane triblock copolymer was successfully demonstrated. This system efficiently utilized light-induced ATP to drive glucose synthesis, and 5.2 μg ml(-1) glucose was synthesized in 0.78-ml reaction buffer in 7 h. Light-dependent reactions were found to be the bottleneck of the studied artificial photosynthesis system.

  15. Glucose-installed, SPIO-loaded PEG- b-PCL micelles as MR contrast agents to target prostate cancer cells

    Science.gov (United States)

    Theerasilp, Man; Sunintaboon, Panya; Sungkarat, Witaya; Nasongkla, Norased

    2017-11-01

    Polymeric micelles of poly(ethylene glycol)- block-poly(ɛ-caprolactone) bearing glucose analog encapsulated with superparamagnetic iron oxide nanoparticles (Glu-SPIO micelles) were synthesized as an MRI contrast agent to target cancer cells based on high-glucose metabolism. Compared to SPIO micelles (non-targeting SPIO micelles), Glu-SPIO micelles demonstrated higher toxicity to human prostate cancer cell lines (PC-3) at high concentration. Atomic absorption spectroscopy was used to determine the amount of iron in cells. It was found that the iron in cancer cells treated by Glu-SPIO micelles were 27-fold higher than cancer cells treated by SPIO micelles at the iron concentration of 25 ppm and fivefold at the iron concentration of 100 ppm. To implement Glu-SPIO micelles as a MR contrast agent, the 3-T clinical MRI was applied to determine transverse relaxivities ( r 2*) and relaxation rate (1/ T 2*) values. In vitro MRI showed different MRI signal from cancer cells after cellular uptake of SPIO micelles and Glu-SPIO micelles. Glu-SPIO micelles was highly sensitive with the r 2* in agarose gel at 155 mM-1 s-1. Moreover, the higher 1/ T 2* value was found for cancer cells treated with Glu-SPIO micelles. These results supported that glucose ligand increased the cellular uptake of micelles by PC-3 cells with over-expressing glucose transporter on the cell membrane. Thus, glucose can be used as a small molecule ligand for targeting prostate cancer cells overexpressing glucose transporter.

  16. Sleep duration and sleep quality are associated differently with alterations of glucose homeostasis.

    Science.gov (United States)

    Byberg, S; Hansen, A-L S; Christensen, D L; Vistisen, D; Aadahl, M; Linneberg, A; Witte, D R

    2012-09-01

    Studies suggest that inadequate sleep duration and poor sleep quality increase the risk of impaired glucose regulation and diabetes. However, associations with specific markers of glucose homeostasis are less well explained. The objective of this study was to explore possible associations of sleep duration and sleep quality with markers of glucose homeostasis and glucose tolerance status in a healthy population-based study sample. The study comprised 771 participants from the Danish, population-based cross-sectional 'Health2008' study. Sleep duration and sleep quality were measured by self-report. Markers of glucose homeostasis were derived from a 3-point oral glucose tolerance test and included fasting plasma glucose, 2-h plasma glucose, HbA(1c), two measures of insulin sensitivity (the insulin sensitivity index(0,120) and homeostasis model assessment of insulin sensitivity), the homeostasis model assessment of β-cell function and glucose tolerance status. Associations of sleep duration and sleep quality with markers of glucose homeostasis and tolerance were analysed by multiple linear and logistic regression. A 1-h increment in sleep duration was associated with a 0.3 mmol/mol (0.3%) decrement in HbA(1c) and a 25% reduction in the risk of having impaired glucose regulation. Further, a 1-point increment in sleep quality was associated with a 2% increase in both the insulin sensitivity index(0,120) and homeostasis model assessment of insulin sensitivity, as well as a 1% decrease in homeostasis model assessment of β-cell function. In the present study, shorter sleep duration was mainly associated with later alterations in glucose homeostasis, whereas poorer sleep quality was mainly associated with earlier alterations in glucose homeostasis. Thus, adopting healthy sleep habits may benefit glucose metabolism in healthy populations. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

  17. Higher Education

    Science.gov (United States)

    & Development (LDRD) National Security Education Center (NSEC) Office of Science Programs Richard P Databases National Security Education Center (NSEC) Center for Nonlinear Studies Engineering Institute Scholarships STEM Education Programs Teachers (K-12) Students (K-12) Higher Education Regional Education

  18. Facile direct electron transfer in glucose oxidase modified electrodes

    International Nuclear Information System (INIS)

    Wang Dan; Chen Liwei

    2009-01-01

    Glucose oxidase (GOx) is widely used in the glucose biosensor industry. However, mediatorless direct electron transfer (DET) from GOx to electrode surfaces is very slow. Recently, mediatorless DET has been reported via the incorporation of nanomaterials such as carbon nanotubes and nanoparticles in the modification of electrodes. Here we report GOx electrodes showing DET without the need for any nanomaterials. The enzyme after immobilization with poly-L-lysine (PLL) and Nafion retains the biocatalytic activities and oxidizes glucose efficiently. The amperometric response of Nafion-PLL-GOx modified electrode is linearly proportional to the concentration of glucose up to 10 mM with a sensitivity of 0.75 μA/mM at a low detection potential (-0.460 V vs. Ag/AgCl). The methodology developed in this study will have impact on glucose biosensors and biofuel cells and may potentially simplify enzyme immobilization in other biosensing systems.

  19. Enzyme-functionalized thin-cladding long-period fiber grating in transition mode at dispersion turning point for sugar-level and glucose detection

    Science.gov (United States)

    Badmos, Abdulyezir A.; Sun, Qizhen; Sun, Zhongyuan; Zhang, Junxi; Yan, Zhijun; Lutsyk, Petro; Rozhin, Alex; Zhang, Lin

    2017-02-01

    Enzyme-functionalized dual-peak long-period fiber grating (LPFG) inscribed in 80-μm-cladding B/Ge codoped single-mode fiber is presented for sugar-level and specific glucose detection. Before enzyme functionalization, the dual-peak LPFG was employed for refractive index sensing and sugar-level detection and high sensitivities of ˜4298.20 nm/RIU and 4.6696 nm/% were obtained, respectively. Glucose detection probe was attained by surface functionalization of the dual-peak LPFG via covalent binding with aminopropyl triethoxysilane used as a binding site. Optical micrographs confirmed the presence of enzyme. The surface-functionalized dual-peak LPFG was tested with D-(+)-glucose solution of different concentrations. While the peak 2 at the longer wavelength was suitable only to measure lower glucose concentration (0.1 to 1.6 mg/ml) recording a high sensitivity of 12.21±0.19 nm/(mg/ml), the peak 1 at the shorter wavelength was able to measure a wider range of glucose concentrations (0.1 to 3.2 mg/ml) exhibiting a maximum resonance wavelength shift of 7.12±0.12 nm/mg/ml. The enzyme-functionalized dual-peak LPFG has the advantage of direct inscription of highly sensitive grating structures in thin-cladding fibre without etching, and most significantly, its sensitivity improvement of approximately one order of magnitude higher than previously reported LPFG and excessively tilted fibre grating (Ex-TFG) for glucose detection.

  20. Glucose-mediated control of ghrelin release from primary cultures of gastric mucosal cells

    Science.gov (United States)

    Sakata, Ichiro; Park, Won-Mee; Walker, Angela K.; Piper, Paul K.; Chuang, Jen-Chieh; Osborne-Lawrence, Sherri

    2012-01-01

    The peptide hormone ghrelin is released from a distinct group of gastrointestinal cells in response to caloric restriction, whereas its levels fall after eating. The mechanisms by which ghrelin secretion is regulated remain largely unknown. Here, we have used primary cultures of mouse gastric mucosal cells to investigate ghrelin secretion, with an emphasis on the role of glucose. Ghrelin secretion from these cells upon exposure to different d-glucose concentrations, the glucose antimetabolite 2-deoxy-d-glucose, and other potential secretagogues was assessed. The expression profile of proteins involved in glucose transport, metabolism, and utilization within highly enriched pools of mouse ghrelin cells and within cultured ghrelinoma cells was also determined. Ghrelin release negatively correlated with d-glucose concentration. Insulin blocked ghrelin release, but only in a low d-glucose environment. 2-Deoxy-d-glucose prevented the inhibitory effect of high d-glucose exposure on ghrelin release. mRNAs encoding several facilitative glucose transporters, hexokinases, the ATP-sensitive potassium channel subunit Kir6.2, and sulfonylurea type 1 receptor were expressed highly within ghrelin cells, although neither tolbutamide nor diazoxide exerted direct effects on ghrelin secretion. These findings suggest that direct exposure of ghrelin cells to low ambient d-glucose stimulates ghrelin release, whereas high d-glucose and glucose metabolism within ghrelin cells block ghrelin release. Also, low d-glucose sensitizes ghrelin cells to insulin. Various glucose transporters, channels, and enzymes that mediate glucose responsiveness in other cell types may contribute to the ghrelin cell machinery involved in regulating ghrelin secretion under these different glucose environments, although their exact roles in ghrelin release remain uncertain. PMID:22414807

  1. Hyperglycemia (High Blood Glucose)

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  14. Enhanced muscle glucose metabolism after exercise in the rat

    DEFF Research Database (Denmark)

    Garetto, L P; Richter, Erik; Goodman, M N

    1984-01-01

    glycogen was substantially repleted at the time (30 min postexercise) that glucose m