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Sample records for glucose absorption rates

  1. The rate of intestinal glucose absorption is correlated with plasma glucose-dependent insulinotropic polypeptide concentrations in healthy men

    DEFF Research Database (Denmark)

    Wachters-Hagedoorn, Renate E; Priebe, Marion G; Heimweg, Janneke A J

    2006-01-01

    and slowly available glucose. In a crossover study, glucose, insulin, GLP-1, and GIP concentrations were monitored for 6 h after consumption of glucose, uncooked cornstarch (UCCS) or corn pasta in 7 healthy men. All test meals were naturally labeled with 13C. Using a primed, continuous D-[6,6-2H2]glucose...... in the early postprandial phase (15-90 min) occurred after consumption of glucose. There was a strong positive within-subject correlation between RaEx and GIP concentrations (r = 0.73, P meals. Rapidly and slowly digestible carbohydrates differ considerably in their ability to stimulate...

  2. Glucose absorption in acute peritoneal dialysis.

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    Podel, J; Hodelin-Wetzel, R; Saha, D C; Burns, G

    2000-04-01

    During acute peritoneal dialysis (APD), it is known that glucose found in the dialysate solution contributes to the provision of significant calories. It has been well documented in continuous ambulatory peritoneal dialysis (CAPD) that glucose absorption occurs. In APD, however, it remains unclear how much glucose absorption actually does occur. Therefore, the purpose of this study was to determine whether it is appropriate to use the formula used to calculate glucose absorption in CAPD (Grodstein et al) among patients undergoing APD. Actual measurements of glucose absorption (Method I) were calculated in 9 patients undergoing APD treatment for >24 hours who were admitted to the intensive care unit. Glucose absorption using the Grodstein et al formula (Method II) was also determined and compared with the results of actual measurements. The data was then further analyzed based on the factors that influence glucose absorption, specifically dwell time and concentration. The mean total amount of glucose absorbed was 43% +/- 15%. However, when dwell time and concentration were further examined, significant differences were noted. Method I showed a cumulative increase over time. Method II showed that absorption was fixed. This suggests that with the variation in dwell time commonly seen in the acute care setting, the use of Method II may not be accurate. In each of the 2 methods, a significant difference in glucose absorption was noted when comparing the use of 1.5% and 4.25% dialysate concentrations. The established formula designed for CAPD should not be used for calculating glucose absorption in patients receiving APD because variation in dwell time and concentration should be taken into account. Because of the time constraints and staffing required to calculate each exchange individually, combined with the results of the study, we recommend the use of the percentage estimate of 40% to 50%.

  3. Salvianolic acid B Relieves Oxidative Stress in Glucose Absorption ...

    African Journals Online (AJOL)

    Absorption and Utilization of Mice Fed High-Sugar Diet ... Salvianolic acid B, Blood glucose, Reactive oxygen species, Oxidative stress, Sugar diet. ... protein expression in human aortic smooth ... induced by glucose uptake and metabolism [8].

  4. Impact of Glucose Tolerance Status, Sex, and Body Size on Glucose Absorption Patterns During OGTTs

    DEFF Research Database (Denmark)

    Faerch, K.; Pacini, G.; Nolan, J. J.

    2013-01-01

    OBJECTIVEWe studied whether patterns of glucose absorption during oral glucose tolerance tests (OGTTs) were abnormal in individuals with impaired glucose regulation and whether they were related to sex and body size (height and fat-free mass). We also examined how well differences in insulin......, reflected the differences for these parameters between those with normal and impaired glucose regulation as measured by gold-standard tests.CONCLUSIONSGlucose absorption patterns during an OGTT are significantly related to plasma glucose levels and body size, which should be taken into account when.......RESULTSMore rapid glucose absorption (P 0.036) and reduced late glucose absorption (P 0.039) were observed in the i-IFG group relative to NGT and i-IGT groups. Women with i-IGT had a lower early glucose absorption than did men with i-IGT (P = 0.041); however, this difference did not persist when differences in body...

  5. Hydroxycitric acid delays intestinal glucose absorption in rats

    NARCIS (Netherlands)

    Wielinga, PY; Wachters-Hagedoorn, RE; Bouter, B; van Dijk, TH; Stellaard, F; Nieuwenhuizen, AG; Verkade, HJ; Scheurink, AJW; Nieuwenhuizen, Arie G.; Verkade, Henkjan J.

    In this study, we investigated in rats if hydroxycitric acid (HCA) reduces the postprandial glucose response by affecting gastric emptying or intestinal glucose absorption. We compared the effect of regulator HCA (310 mg/kg) and vehicle (control) on the glucose response after an intragastric or

  6. Effects of xylitol on carbohydrate digesting enzymes activity, intestinal glucose absorption and muscle glucose uptake: a multi-mode study.

    Science.gov (United States)

    Chukwuma, Chika Ifeanyi; Islam, Md Shahidul

    2015-03-01

    The present study investigated the possible mechanism(s) behind the effects of xylitol on carbohydrate digesting enzymes activity, muscle glucose uptake and intestinal glucose absorption using in vitro, ex vivo and in vivo experimental models. The effects of increasing concentrations of xylitol (2.5%-40% or 164.31 mM-2628.99 mM) on alpha amylase and alpha glucosidase activity in vitro and intestinal glucose absorption and muscle glucose uptake were investigated under ex vivo conditions. Additionally, the effects of an oral bolus dose of xylitol (1 g per kg BW) on gastric emptying and intestinal glucose absorption and digesta transit in the different segments of the intestinal tract were investigated in normal and type 2 diabetic rats at 1 hour after dose administration, when phenol red was used as a recovery marker. Xylitol exhibited concentration-dependent inhibition of alpha amylase (IC₅₀ = 1364.04 mM) and alpha glucosidase (IC₅₀ = 1127.52 mM) activity in vitro and small intestinal glucose absorption under ex vivo condition. Xylitol also increased dose dependent muscle glucose uptake with and without insulin, although the uptake was not significantly affected by the addition of insulin. Oral single bolus dose of xylitol significantly delayed gastric emptying, inhibited intestinal glucose absorption but increased the intestinal digesta transit rate in both normal and diabetic rats compared to their respective controls. The data of this study suggest that xylitol reduces intestinal glucose absorption via inhibiting major carbohydrate digesting enzymes, slowing gastric emptying and fastening the intestinal transit rate, but increases muscle glucose uptake in normal and type 2 diabetic rats.

  7. Comparison of the effect of sorbitol and glucose on calcium absorption in postmenopausal women

    International Nuclear Information System (INIS)

    Francis, R.M.; Peacock, M.; Barkworth, S.A.; Marshall, D.H.

    1986-01-01

    It has been suggested that the oral administration of sorbitol promotes calcium absorption, while glucose has no effect. We have therefore compared the effect of oral sorbitol and glucose on the absorption of radiocalcium from low and high carrier loads in healthy postmenopausal women. In a control group of 20 women given neither sorbitol nor glucose, the mean +/- SEM fractional radiocalcium absorption rate from a low carrier load was 0.65 +/- 0.05 (fraction of dose/h). In a second group of 10 women the fractional absorption rate from the low carrier load was lower (p less than 0.05) with 10 g sorbitol (0.48 +/- 0.05) than with 10 g glucose (0.65 +/- 0.08). Fractional absorption of radiocalcium from a high carrier load measured in a third group of seven women using two isotopes (oral 45Ca, IV 47Ca) was also lower (p less than 0.001) with 10 g sorbitol (0.22 +/- 0.01, fraction/3 h) than with 10 g glucose (0.29 +/- 0.02). The results suggest that calcium absorption from a low carrier load is unaltered by glucose but that absorption of calcium from both low and high carrier loads is lower with sorbitol than with glucose

  8. Exercise, Insulin Absorption Rates, and Artificial Pancreas Control

    Science.gov (United States)

    Frank, Spencer; Hinshaw, Ling; Basu, Rita; Basu, Ananda; Szeri, Andrew J.

    2016-11-01

    Type 1 Diabetes is characterized by an inability of a person to endogenously produce the hormone insulin. Because of this, insulin must be injected - usually subcutaneously. The size of the injected dose and the rate at which the dose reaches the circulatory system have a profound effect on the ability to control glucose excursions, and therefore control of diabetes. However, insulin absorption rates via subcutaneous injection are variable and depend on a number of factors including tissue perfusion, physical activity (vasodilation, increased capillary throughput), and other tissue geometric and physical properties. Exercise may also have a sizeable effect on the rate of insulin absorption, which can potentially lead to dangerous glucose levels. Insulin-dosing algorithms, as implemented in an artificial pancreas controller, should account accurately for absorption rate variability and exercise effects on insulin absorption. The aforementioned factors affecting insulin absorption will be discussed within the context of both fluid mechanics and data driven modeling approaches.

  9. Hummingbirds rely on both paracellular and carrier-mediated intestinal glucose absorption to fuel high metabolism

    Science.gov (United States)

    McWhorter, Todd J; Bakken, Bradley Hartman; Karasov, William H; del Rio, Carlos Martínez

    2005-01-01

    Twenty years ago, the highest active glucose transport rate and lowest passive glucose permeability in vertebrates were reported in Rufous and Anna's hummingbirds (Selasphorus rufus, Calypte anna). These first measurements of intestinal nutrient absorption in nectarivores provided an unprecedented physiological foundation for understanding their foraging ecology. They showed that physiological processes are determinants of feeding behaviour. The conclusion that active, mediated transport accounts for essentially all glucose absorption in hummingbirds influenced two decades of subsequent research on the digestive physiology and nutritional ecology of nectarivores. Here, we report new findings demonstrating that the passive permeability of hummingbird intestines to glucose is much higher than previously reported, suggesting that not all sugar uptake is mediated. Even while possessing the highest active glucose transport rates measured in vertebrates, hummingbirds must rely partially on passive non-mediated intestinal nutrient absorption to meet their high mass-specific metabolic demands. PMID:17148346

  10. Myo-inositol inhibits intestinal glucose absorption and promotes muscle glucose uptake: a dual approach study.

    Science.gov (United States)

    Chukwuma, Chika Ifeanyi; Ibrahim, Mohammed Auwal; Islam, Md Shahidul

    2016-12-01

    The present study investigated the effects of myo-inositol on muscle glucose uptake and intestinal glucose absorption ex vivo as well as in normal and type 2 diabetes model of rats. In ex vivo study, both intestinal glucose absorption and muscle glucose uptake were studied in isolated rat jejunum and psoas muscle respectively in the presence of increasing concentrations (2.5 % to 20 %) of myo-inositol. In the in vivo study, the effect of a single bolus dose (1 g/kg bw) of oral myo-inositol on intestinal glucose absorption, blood glucose, gastric emptying and digesta transit was investigated in normal and type 2 diabetic rats after 1 h of co-administration with 2 g/kg bw glucose, when phenol red was used as a recovery marker. Myo-inositol inhibited intestinal glucose absorption (IC 50  = 28.23 ± 6.01 %) and increased muscle glucose uptake, with (GU 50  = 2.68 ± 0.75 %) or without (GU 50  = 8.61 ± 0.55 %) insulin. Additionally, oral myo-inositol not only inhibited duodenal glucose absorption and reduced blood glucose increase, but also delayed gastric emptying and accelerated digesta transit in both normal and diabetic animals. Results of this study suggest that dietary myo-inositol inhibits intestinal glucose absorption both in ex vivo and in normal or diabetic rats and also promotes muscle glucose uptake in ex vivo condition. Hence, myo-inositol may be further investigated as a possible anti-hyperglycaemic dietary supplement for diabetic foods and food products.

  11. Glucose Absorption by the Bacillary Band of Trichuris muris.

    Directory of Open Access Journals (Sweden)

    Tina V A Hansen

    2016-09-01

    Full Text Available A common characteristic of Trichuris spp. infections in humans and animals is the variable but low efficacy of single-dose benzimidazoles currently used in mass drug administration programmes against human trichuriasis. The bacillary band, a specialised morphological structure of Trichuris spp., as well as the unique partly intracellular habitat of adult Trichuris spp. may affect drug absorption and perhaps contribute to the low drug accumulation in the worm. However, the exact function of the bacillary band is still unknown.We studied the dependency of adult Trichuris muris on glucose and/or amino acids for survival in vitro and the absorptive function of the bacillary band. The viability of the worms was evaluated using a motility scale from 0 to 3, and the colorimetric assay Alamar Blue was utilised to measure the metabolic activity. The absorptive function of the bacillary band in living worms was explored using a fluorescent glucose analogue (6-NBDG and confocal microscopy. To study the absorptive function of the bacillary band in relation to 6-NBDG, the oral uptake was minimised or excluded by sealing the oral cavity with glue and agarose.Glucose had a positive effect on both the motility (p < 0.001 and metabolic activity (p < 0.001 of T. muris in vitro, whereas this was not the case for amino acids. The 6-NBDG was observed in the pores of the bacillary band and within the stichocytes of the living worms, independent of oral sealing.Trichuris muris is dependent on glucose for viability in vitro, and the bacillary band has an absorptive function in relation to 6-NBDG, which accumulates within the stichocytes. The absorptive function of the bacillary band calls for an exploration of its possible role in the uptake of anthelmintics, and as a potential anthelmintic target relevant for future drug development.

  12. Exogenous glucagon-like peptide-1 attenuates glucose absorption and reduces blood glucose concentration after small intestinal glucose delivery in critical illness.

    Science.gov (United States)

    Miller, Asaf; Deane, Adam M; Plummer, Mark P; Cousins, Caroline E; Chapple, Lee-Anne S; Horowitz, Michael; Chapman, Marianne J

    2017-03-01

    To evaluate the effect of exogenous glucagonlike peptide-1 (GLP-1) on small intestinal glucose absorption and blood glucose concentrations during critical illness. A prospective, blinded, placebo-controlled, cross-over, randomised trial in a mixed medical-surgical adult intensive care unit, with 12 mechanically ventilated critically ill patients, who were suitable for receiving small intestinal nutrient. On consecutive days, in a randomised order, participants received intravenous GLP-1 (1.2 pmol/ kg/min) or placebo (0.9% saline) as a continuous infusion over 270 minutes. After 6 hours of fasting, intravenous infusions of GLP-1 or placebo began at T = -30 min (in which T = time), with the infusion maintained at a constant rate until study completion at T = 240 min. At T = 0 min, a 100 mL bolus of mixed liquid nutrient meal (1 kcal/mL) containing 3 g of 3-O-methyl-D-gluco-pyranose (3-OMG), a marker of glucose absorption, was administered directly into the small intestine, via a post-pyloric catheter, over 6 minutes. Blood samples were taken at regular intervals for the measurement of plasma glucose and 3-OMG concentrations. Intravenous GLP-1 attenuated initial small intestinal glucose absorption (mean area under the curve [AUC] 0-30 for 3-OMG: GLP-1 group, 4.4 mmol/L/min [SEM, 0.9 mmol/L/min] v placebo group, 6.5 mmol/L/min [SEM, 1.0 mmol/L/min]; P = 0.01), overall small intestinal glucose absorption (mean AUC 0-240 for 3-OMG: GLP-1, 68.2 mmol/L/ min [SEM, 4.7 mmol/L/min] v placebo, 77.7 mmol/L/min [SEM, 4.4 mmol/lLmin]; P = 0.02), small intestinal glucose absorption and overall blood glucose concentration (mean AUC 0-240 for blood glucose: GLP-1, 2062 mmol/L/min [SEM, 111 mmol/L/min] v placebo 2328 mmol/L/min [SEM, 145 mmol/L/min]; P = 0.005). Short-term administration of exogenous GLP-1 reduces small intestinal glucose absorption for up to 4 hours during critical illness. This is likely to be an additional mechanism for the glucose-lowering effect of this agent.

  13. 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.

  14. Effect of radiation on glucose absorption in the nouse jejunum in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Overgaard, J.; Matsui, Masasuke (Danish Cancer Society, Aarhus (Denmark). Department of Experimental Clinical Oncology)

    1990-05-01

    In an attempt to develop a clinical assay for intestinal damage, the relationship between radiation dose and glucose absorpion in the jejunum has been investigated. Lightly anesthetised C3D2F1 mice had their upper abdomen irradiated. The intestine was exteriorized and a 10-cm segment of the jejunum was isolated and included in a closed circuit perfusion loop. An isotonic solution containing 2 mg/ml D-glucose was perfused in 2 h and the rate of glucose absorption calculated. The absorption decreased as a function of dose and time after irradiation with the most prominent reduction after 4-5 days, returning to normal within a week after irradiation. A dose-response relationship was found after single doses between 5 and 17.5 Gy. Split-dose recovery of approximately 7.5. Gy was fond within 2-4 h. This absorption insufficiency was only found to be present acutely, and no late abnormalities were seen for times greater than 12 months after irradiation. The results correlated with other functional endpoints such as absorptive surface. This assay seems suitable to demonstrate (acute) functional intestinal radiation damage and has obvious clinical applicability. (author). 31 refs.; 6 figs.; 1 tab.

  15. The effect of gastric inhibitory polypeptide on intestinal glucose absorption and intestinal motility in mice

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Eiichi [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Hosokawa, Masaya [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Faculty of Human Sciences, Tezukayama Gakuin University, Osaka (Japan); Harada, Norio; Yamane, Shunsuke; Hamasaki, Akihiro; Toyoda, Kentaro; Fujimoto, Shimpei; Fujita, Yoshihito; Fukuda, Kazuhito [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Tsukiyama, Katsushi; Yamada, Yuichiro [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Department of Internal Medicine, Division of Endocrinology, Diabetes and Geriatric Medicine, Akita University School of Medicine, Akita (Japan); Seino, Yutaka [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Kansai Electric Power Hospital, Osaka (Japan); Inagaki, Nobuya, E-mail: inagaki@metab.kuhp.kyoto-u.ac.jp [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); CREST of Japan Science and Technology Cooperation (JST), Kyoto (Japan)

    2011-01-07

    Research highlights: {yields} Exogenous GIP inhibits intestinal motility through a somatostatin-mediated pathway. {yields} Exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility. {yields} The GIP-receptor-mediated action in intestine does not involve in GLP-1-mediated pathway. -- Abstract: Gastric inhibitory polypeptide (GIP) is released from the small intestine upon meal ingestion and increases insulin secretion from pancreatic {beta} cells. Although the GIP receptor is known to be expressed in small intestine, the effects of GIP in small intestine are not fully understood. This study was designed to clarify the effect of GIP on intestinal glucose absorption and intestinal motility. Intestinal glucose absorption in vivo was measured by single-pass perfusion method. Incorporation of [{sup 14}C]-glucose into everted jejunal rings in vitro was used to evaluate the effect of GIP on sodium-glucose co-transporter (SGLT). Motility of small intestine was measured by intestinal transit after oral administration of a non-absorbed marker. Intraperitoneal administration of GIP inhibited glucose absorption in wild-type mice in a concentration-dependent manner, showing maximum decrease at the dosage of 50 nmol/kg body weight. In glucagon-like-peptide-1 (GLP-1) receptor-deficient mice, GIP inhibited glucose absorption as in wild-type mice. In vitro examination of [{sup 14}C]-glucose uptake revealed that 100 nM GIP did not change SGLT-dependent glucose uptake in wild-type mice. After intraperitoneal administration of GIP (50 nmol/kg body weight), small intestinal transit was inhibited to 40% in both wild-type and GLP-1 receptor-deficient mice. Furthermore, a somatostatin receptor antagonist, cyclosomatostatin, reduced the inhibitory effect of GIP on both intestinal transit and glucose absorption in wild-type mice. These results demonstrate that exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility through a somatostatin

  16. The effect of gastric inhibitory polypeptide on intestinal glucose absorption and intestinal motility in mice

    International Nuclear Information System (INIS)

    Ogawa, Eiichi; Hosokawa, Masaya; Harada, Norio; Yamane, Shunsuke; Hamasaki, Akihiro; Toyoda, Kentaro; Fujimoto, Shimpei; Fujita, Yoshihito; Fukuda, Kazuhito; Tsukiyama, Katsushi; Yamada, Yuichiro; Seino, Yutaka; Inagaki, Nobuya

    2011-01-01

    Research highlights: → Exogenous GIP inhibits intestinal motility through a somatostatin-mediated pathway. → Exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility. → The GIP-receptor-mediated action in intestine does not involve in GLP-1-mediated pathway. -- Abstract: Gastric inhibitory polypeptide (GIP) is released from the small intestine upon meal ingestion and increases insulin secretion from pancreatic β cells. Although the GIP receptor is known to be expressed in small intestine, the effects of GIP in small intestine are not fully understood. This study was designed to clarify the effect of GIP on intestinal glucose absorption and intestinal motility. Intestinal glucose absorption in vivo was measured by single-pass perfusion method. Incorporation of [ 14 C]-glucose into everted jejunal rings in vitro was used to evaluate the effect of GIP on sodium-glucose co-transporter (SGLT). Motility of small intestine was measured by intestinal transit after oral administration of a non-absorbed marker. Intraperitoneal administration of GIP inhibited glucose absorption in wild-type mice in a concentration-dependent manner, showing maximum decrease at the dosage of 50 nmol/kg body weight. In glucagon-like-peptide-1 (GLP-1) receptor-deficient mice, GIP inhibited glucose absorption as in wild-type mice. In vitro examination of [ 14 C]-glucose uptake revealed that 100 nM GIP did not change SGLT-dependent glucose uptake in wild-type mice. After intraperitoneal administration of GIP (50 nmol/kg body weight), small intestinal transit was inhibited to 40% in both wild-type and GLP-1 receptor-deficient mice. Furthermore, a somatostatin receptor antagonist, cyclosomatostatin, reduced the inhibitory effect of GIP on both intestinal transit and glucose absorption in wild-type mice. These results demonstrate that exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility through a somatostatin-mediated pathway rather

  17. Evanescent Wave Absorption Based Fiber Sensor for Measuring Glucose Solution Concentration

    Science.gov (United States)

    Marzuki, Ahmad; Candra Pratiwi, Arni; Suryanti, Venty

    2018-03-01

    An optical fiber sensor based on evanescent wave absorption designed for measuring glucose solution consentration was proposed. The sensor was made to detect absorbance of various wavelength in the glucose solution. The sensing element was fabricated by side polishing of multimode polymer optical fiber to form a D-shape. The sensing element was immersed in different concentration of glucoce solution. As light propagated through the optical fiber, the evanescent wave interacted with the glucose solution. Light was absorbed by the glucose solution. The larger concentration the glucose solution has, the more the evanescent wave was absorbed in particular wavelenght. Here in this paper, light absorbtion as function of glucose concentration was measured as function of wavelength (the color of LED). We have shown that the proposed sensor can demonstrated an increase of light absorption as function of glucose concentration.

  18. Semimechanistic model describing gastric emptying and glucose absorption in healthy subjects and patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Alskär, Oskar; Bagger, Jonatan I; Røge, Rikke M.

    2016-01-01

    The integrated glucose-insulin (IGI) model is a previously published semimechanistic model that describes plasma glucose and insulin concentrations after glucose challenges. The aim of this work was to use knowledge of physiology to improve the IGI model's description of glucose absorption and ga...... model provides a better description and improves the understanding of dynamic glucose tests involving oral glucose....... and gastric emptying after tests with varying glucose doses. The developed model's performance was compared to empirical models. To develop our model, data from oral and intravenous glucose challenges in patients with type 2 diabetes and healthy control subjects were used together with present knowledge...... glucose absorption was superior to linear absorption regardless of the gastric emptying model applied. The semiphysiological model developed performed better than previously published empirical models and allows better understanding of the mechanisms underlying glucose absorption. In conclusion, our new...

  19. Maltitol inhibits small intestinal glucose absorption and increases insulin mediated muscle glucose uptake ex vivo but not in normal and type 2 diabetic rats.

    Science.gov (United States)

    Chukwuma, Chika Ifeanyi; Ibrahim, Mohammed Auwal; Islam, Md Shahidul

    2017-02-01

    This study investigated the effects of maltitol on intestinal glucose absorption and muscle glucose uptake using ex vivo and in vivo experimental models. The ex vivo experiment was conducted in isolated jejunum and psoas muscle from normal rats. The in vivo study investigated the effects of a single bolus dose of maltitol on gastric emptying, intestinal glucose absorption and digesta transit in normal and type 2 diabetic rats. Maltitol inhibited glucose absorption in isolated rat jejunum and increased glucose uptake in isolated rat psoas muscle in the presence of insulin but not in the absence of insulin. In contrast, maltitol did not significantly (p > 0.05) alter small intestinal glucose absorption or blood glucose levels as well as gastric emptying and digesta transit in normal or type 2 diabetic rats. The results suggest that maltitol may not be a suitable dietary supplement for anti-diabetic food and food products to improve glycemic control.

  20. A computer model simulating human glucose absorption and metabolism in health and metabolic disease states [version 1; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Richard J. Naftalin

    2016-04-01

    Full Text Available A computer model designed to simulate integrated glucose-dependent changes in splanchnic blood flow with small intestinal glucose absorption, hormonal and incretin circulation and hepatic and systemic metabolism in health and metabolic diseases e.g. non-alcoholic fatty liver disease, (NAFLD, non-alcoholic steatohepatitis, (NASH and type 2 diabetes mellitus, (T2DM demonstrates how when glucagon-like peptide-1, (GLP-1 is synchronously released into the splanchnic blood during intestinal glucose absorption, it stimulates superior mesenteric arterial (SMA blood flow and by increasing passive intestinal glucose absorption, harmonizes absorption with its distribution and metabolism. GLP-1 also synergises insulin-dependent net hepatic glucose uptake (NHGU. When GLP-1 secretion is deficient post-prandial SMA blood flow is not increased and as NHGU is also reduced, hyperglycaemia follows. Portal venous glucose concentration is also raised, thereby retarding the passive component of intestinal glucose absorption.   Increased pre-hepatic sinusoidal resistance combined with portal hypertension leading to opening of intrahepatic portosystemic collateral vessels are NASH-related mechanical defects that alter the balance between splanchnic and systemic distributions of glucose, hormones and incretins.The model reveals the latent contribution of portosystemic shunting in development of metabolic disease. This diverts splanchnic blood content away from the hepatic sinuses to the systemic circulation, particularly during the glucose absorptive phase of digestion, resulting in inappropriate increases in insulin-dependent systemic glucose metabolism.  This hastens onset of hypoglycaemia and thence hyperglucagonaemia. The model reveals that low rates of GLP-1 secretion, frequently associated with T2DM and NASH, may be also be caused by splanchnic hypoglycaemia, rather than to intrinsic loss of incretin secretory capacity. These findings may have therapeutic

  1. Sorbitol increases muscle glucose uptake ex vivo and inhibits intestinal glucose absorption ex vivo and in normal and type 2 diabetic rats.

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    Chukwuma, Chika Ifeanyi; Islam, Md Shahidul

    2017-04-01

    Previous studies have suggested that sorbitol, a known polyol sweetener, possesses glycemic control potentials. However, the effect of sorbitol on intestinal glucose absorption and muscle glucose uptake still remains elusive. The present study investigated the effects of sorbitol on intestinal glucose absorption and muscle glucose uptake as possible anti-hyperglycemic or glycemic control potentials using ex vivo and in vivo experimental models. Sorbitol (2.5% to 20%) inhibited glucose absorption in isolated rat jejuna (IC 50 = 14.6% ± 4.6%) and increased glucose uptake in isolated rat psoas muscle with (GU 50 = 3.5% ± 1.6%) or without insulin (GU 50 = 7.0% ± 0.5%) in a concentration-dependent manner. Furthermore, sorbitol significantly delayed gastric emptying, accelerated digesta transit, inhibited intestinal glucose absorption, and reduced blood glucose increase in both normoglycemic and type 2 diabetic rats after 1 h of coingestion with glucose. Data of this study suggest that sorbitol exhibited anti-hyperglycemic potentials, possibly via increasing muscle glucose uptake ex vivo and reducing intestinal glucose absorption in normal and type 2 diabetic rats. Hence, sorbitol may be further investigated as a possible anti-hyperglycemic sweetener.

  2. Effect to the Glycolit which the glucose absorption marked with a 14 C in rats

    International Nuclear Information System (INIS)

    Fleitas Estevez, Andres; Simon Carballo, Rafael; Coma Alfonso, Cristina; Derivet Zarzabal, Milagros

    2001-01-01

    It has been proved that glicolit, a product obtained from natural zeolites, delays the intestinal absorption of glucose and prevents the elevation of its level in blood in the postprandial periods. The authors go deep into the knowledge of the mechanism of action of glicolit as an antihyperglycemic agent by using a radioisotopic technique, since these techniques are very specific and have a certain independence of the environment in which the absorption and incorporation of glucose to blood occurs. l5 rats were studied. They were administered a preparation of glucose marked with a 14 C during fasting. 6 of them received only this preparation (group 1, control) and the other 6 were given this preparation combined with glicolit (group 2). Blood was extracted at different times to measure glucose in plasma by radioactive counts. Differences were observed between both groups of rats in the areas under the curves of absorption of glucose, which shows the usefulness of the this method to measure the antihyperglycemic effect of glicolit. The results obtained by the radioisotopic method with glucose marked with a 14 C confirm what has been reported in previous papers and allow us to advance in the study of this possible drug, on having an efficient method

  3. Predicting Insulin Absorption and Glucose Uptake during Exercise in Type 1 Diabetes

    Science.gov (United States)

    Frank, Spencer; Hinshaw, Ling; Basu, Rita; Szeri, Andrew; Basu, Ananda

    2017-11-01

    A dose of insulin infused into subcutaneous tissue has been shown to absorb more quickly during exercise, potentially causing hypoglycemia in persons with type 1 diabetes. We develop a model that relates exercise-induced physiological changes to enhanced insulin-absorption (k) and glucose uptake (GU). Drawing on concepts of the microcirculation we derive a relationship that reveals that k and GU are mainly determined by two physiological parameters that characterize the tissue: the tissue perfusion rate (Q) and the capillary permeability surface area (PS). Independently measured values of Q and PS from the literature are used in the model to make predictions of k and GU. We compare these predictions to experimental observations of healthy and diabetic patients that are given a meal followed by rest or exercise. The experiments show that during exercise insulin concentrations significantly increase and that glucose levels fall rapidly. The model predictions are consistent with the experiments and show that increases in Q and PS directly increase k and GU. This mechanistic understanding provides a basis for handling exercise in control algorithms for an artificial pancreas. Now at University of British Columbia.

  4. Comparison of glucose concentration and glucose absorption from the GI-tract in pigs in whole blood and in plasma

    DEFF Research Database (Denmark)

    Theil, Peter Kappel; Jørgensen, Henry; Larsen, Torben

    2010-01-01

    using a biosensitive electrode (Exp. 1) or a standard colourimetric method (Exp. 2). In general, glucose measured in whole blood was 7-11% lower than in plasma at low glucose levels (3.5-5 mM), whereas the methods agreed well at high glucose levels (10-14 mM). Evaluation of the regression lines between......The present investigation was undertaken to compare glucose absorption from the gastro-intestinal tract quantified in either whole blood or plasma using the arterio-venous differences and portal blood flow measurements. Pigs were surgically modified with catheters in the portal vein...... three different diets with similar contents of starch (470-506 g/kg DM). The diets in both studies differed regarding amount and solubility of fibre. Blood samples were collected repeatedly 0-10 h after morning feeding. Glucose was measured in whole blood using a glucometer (Accu-Chek®) and in plasma...

  5. The absorption of carbon monoxide in COSORB solutions: absorption rate and capacity

    NARCIS (Netherlands)

    Hogendoorn, Kees; van Swaaij, Willibrordus Petrus Maria; Versteeg, Geert

    1995-01-01

    Absorption rate experiments and equilibrium experiments were carried out for the COSORB reaction at 300 K. The equilibrium data at 300 K could reasonably well be described with the following relation: [...] Determination of the kinetics and mechanism of a chemical reaction by means of absorption

  6. Rate of absorption and interfacial area of chlorine into aqueous ...

    African Journals Online (AJOL)

    aghomotsegin

    Due to excellent mass transfer characteristics with energy efficiency jet ejectors can be used in place of ... developed. The rate of absorption predicted from developed model is compared with experimental results. .... Numerical implementation.

  7. Soft black hole absorption rates as conservation laws

    International Nuclear Information System (INIS)

    Avery, Steven G.; Schwab, Burkhard UniversityW.

    2017-01-01

    The absorption rate of low-energy, or soft, electromagnetic radiation by spherically symmetric black holes in arbitrary dimensions is shown to be fixed by conservation of energy and large gauge transformations. We interpret this result as the explicit realization of the Hawking-Perry-Strominger Ward identity for large gauge transformations in the background of a non-evaporating black hole. Along the way we rederive and extend previous analytic results regarding the absorption rate for the minimal scalar and the photon.

  8. Soft black hole absorption rates as conservation laws

    Energy Technology Data Exchange (ETDEWEB)

    Avery, Steven G. [Brown University, Department of Physics,182 Hope St, Providence, RI, 02912 (United States); Michigan State University, Department of Physics and Astronomy,East Lansing, MI, 48824 (United States); Schwab, Burkhard UniversityW. [Harvard University, Center for Mathematical Science and Applications,1 Oxford St, Cambridge, MA, 02138 (United States)

    2017-04-10

    The absorption rate of low-energy, or soft, electromagnetic radiation by spherically symmetric black holes in arbitrary dimensions is shown to be fixed by conservation of energy and large gauge transformations. We interpret this result as the explicit realization of the Hawking-Perry-Strominger Ward identity for large gauge transformations in the background of a non-evaporating black hole. Along the way we rederive and extend previous analytic results regarding the absorption rate for the minimal scalar and the photon.

  9. Starfruit Leaves as Glucose Absorption Inhibitor in Mice’s Small Intestinal Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Rifqi Y Muhammad

    2016-12-01

    Full Text Available Background: Starfruit (Averrhoa carambola leaves contain flavone derivatives that exhibit anti-hyperglycemic effects. This study aims to determine the effect of starfruit leaves in reducing glucose absorption in intestinal epithelial cells of mice. Methods: This study was done by performing perfusion on the small intestines of mice. The mice that were used in this study were divided into four groups. The control group was given glucose solution without infused starfruit leaves whereas, the remaining 3 groups were given 3 mmol (540 mg/dL glucose solution with infused starfruit leaves of varying concentrations; 200, 400, and 600 mg/kg. Samples were collected at 0, 15th, 30th, 45th, and 60th minute. The sample was tested for glucose levels using spectrophotometry. Results: Test of significance showed a significant difference between the control group and the test group with p < 0.05. Conclusions: Starfruit leaves have a reduction effect towards glucose absorption in the small intestines in Wistar strains where the group using 600 mg/kg of infused starfruit leaves have the most significant effect as compared to other groups.

  10. Integrated rate expression for the production of glucose equivalent ...

    Indian Academy of Sciences (India)

    WINTEC

    green plants is discussed. The C4 plants are chosen and in these plants, the rate of photosynthesis does not .... overall CO2 assimilation process and glucose pro-. Figure 1. ..... Thus these plants show an optimal growth of an enzyme activity ...

  11. LX4211 increases serum glucagon-like peptide 1 and peptide YY levels by reducing sodium/glucose cotransporter 1 (SGLT1)-mediated absorption of intestinal glucose.

    Science.gov (United States)

    Powell, David R; Smith, Melinda; Greer, Jennifer; Harris, Angela; Zhao, Sharon; DaCosta, Christopher; Mseeh, Faika; Shadoan, Melanie K; Sands, Arthur; Zambrowicz, Brian; Ding, Zhi-Ming

    2013-05-01

    LX4211 [(2S,3R,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol], a dual sodium/glucose cotransporter 1 (SGLT1) and SGLT2 inhibitor, is thought to decrease both renal glucose reabsorption by inhibiting SGLT2 and intestinal glucose absorption by inhibiting SGLT1. In clinical trials in patients with type 2 diabetes mellitus (T2DM), LX4211 treatment improved glycemic control while increasing circulating levels of glucagon-like peptide 1 (GLP-1) and peptide YY (PYY). To better understand how LX4211 increases GLP-1 and PYY levels, we challenged SGLT1 knockout (-/-) mice, SGLT2-/- mice, and LX4211-treated mice with oral glucose. LX4211-treated mice and SGLT1-/- mice had increased levels of plasma GLP-1, plasma PYY, and intestinal glucose during the 6 hours after a glucose-containing meal, as reflected by area under the curve (AUC) values, whereas SGLT2-/- mice showed no response. LX4211-treated mice and SGLT1-/- mice also had increased GLP-1 AUC values, decreased glucose-dependent insulinotropic polypeptide (GIP) AUC values, and decreased blood glucose excursions during the 6 hours after a challenge with oral glucose alone. However, GLP-1 and GIP levels were not increased in LX4211-treated mice and were decreased in SGLT1-/- mice, 5 minutes after oral glucose, consistent with studies linking decreased intestinal SGLT1 activity with reduced GLP-1 and GIP levels 5 minutes after oral glucose. These data suggest that LX4211 reduces intestinal glucose absorption by inhibiting SGLT1, resulting in net increases in GLP-1 and PYY release and decreases in GIP release and blood glucose excursions. The ability to inhibit both intestinal SGLT1 and renal SGLT2 provides LX4211 with a novel dual mechanism of action for improving glycemic control in patients with T2DM.

  12. Determination of sedimentation rates and absorption coefficient of ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    particles have pores that can absorb radiation. Gamma rays have been used to study the absorption coefficients of cobalt(II) insoluble compounds (Essien and Ekpe, 1998), densities of marine sediments. (Gerland and Villinger, 1995) and soil particle-size distribution (Vaz et al., 1992). In this study, sedimentation rates of ...

  13. Glycolysis-induced discordance between glucose metabolic rates measured with radiolabeled fluorodeoxyglucose and glucose

    International Nuclear Information System (INIS)

    Ackermann, R.F.; Lear, J.L.

    1989-01-01

    We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered [ 18 F]fluorodeoxyglucose (FDG) and [ 14 C]-6-glucose (GLC). FDG-6-phosphate accumulation is proportional to the rate of glucose phosphorylation, which occurs before the divergence of glycolytic (GMg) and oxidative (GMo) glucose metabolism and is therefore related to total cerebral glucose metabolism GMt: GMg + GMo = GMt. With oxidative metabolism, the 14 C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the 14 C label is lost from the brain via lactate production and efflux from the brain. Thus, cerebral GLC metabolite concentration may be more closely related to GMo than to GMt. If true, the glycolytic metabolic rate will be related to the difference between FDG- and GLC-derived LCMRglc. Thus far, we have studied normal awake rats, rats with limbic activation induced by kainic acid (KA), and rats visually stimulated with 16-Hz flashes. In KA-treated rats, significant discordance between FDG and GLC accumulation, which we attribute to glycolysis, occurred only in activated limbic structures. In visually stimulated rats, significant discordance occurred only in the optic tectum

  14. The rate of lactate production from glucose in hearts is not altered by per-deuteration of glucose

    Science.gov (United States)

    Funk, Alexander M.; Anderson, Brian L.; Wen, Xiaodong; Hever, Thomas; Khemtong, Chalermchai; Kovacs, Zoltan; Sherry, A. Dean; Malloy, Craig R.

    2017-11-01

    This study was designed to determine whether perdeuterated glucose experiences a kinetic isotope effect (KIE) as glucose passes through glycolysis and is further oxidized in the tricarboxylic acid (TCA) cycle. Metabolism of deuterated glucose was investigated in two groups of perfused rat hearts. The control group was supplied with a 1:1 mixture of [U-13C6]glucose and [1,6-13C2]glucose, while the experimental group received [U-13C6,U-2H7]glucose and [1,6-13C2]glucose. Tissue extracts were analyzed by 1H, 2H and proton-decoupled 13C NMR spectroscopy. Extensive 2H-13C scalar coupling plus chemical shift isotope effects were observed in the proton-decoupled 13C NMR spectra of lactate, alanine and glutamate. A small but measureable (∼8%) difference in the rate of conversion of [U-13C6]glucose vs. [1,6-13C2]glucose to lactate, likely reflecting rates of Csbnd C bond breakage in the aldolase reaction, but conversion of [U-13C6]glucose versus [U-13C6,U-2H7]glucose to lactate did not differ. This shows that the presence of deuterium in glucose does not alter glycolytic flux. However, there were two distinct effects of deuteration on metabolism of glucose to alanine and oxidation of glucose in the TCA. First, alanine undergoes extensive exchange of methyl deuterons with solvent protons in the alanine amino transferase reaction. Second, there is a substantial kinetic isotope effect in metabolism of [U-13C6,U-2H7]glucose to alanine and glutamate. In the presence of [U-13C6,U-2H7]glucose, alanine and lactate are not in rapid exchange with the same pool of pyruvate. These studies indicate that the appearance of hyperpolarized 13C-lactate from hyperpolarized [U-13C6,U-2H7]glucose is not substantially influenced by a deuterium kinetic isotope effect.

  15. Kinetics of amino acid and glucose absorption following pancreatic diversion in the pig

    Science.gov (United States)

    Rerat, A.; Calmes, R.; Corring, T.; Vaissade, P.

    1996-01-01

    An experiment was conducted in the pig to determine the consequences of deprivation of exocrine pancreatic secretion on the composition and quantity of nutrients absorbed after intake of a balanced diet. Five growing pigs (53.8 kg body weight) were fitted with permanent catheters in the portal vein and the carotid artery and with an electromagnetic flow probe around the portal vein to measure the exchanges between the blood and the intestinal lumen. They were also fitted with a permanent catheter in the duct of Wirsung to educe the exocrine pancreatic secretion and another one in the duodenum in order to reintroduce it. In each animal, glucose, amino-N and amino acid absorption as well as insulin and glucagon production were measured over a period of 10 h after the meal (semi-purified diet based on purified starch and containing 180 g fish meal/kg, DM content of the meal 731 g), either in the presence of pancreatic juice (group C: immediate reintroduction), or in the absence of pancreatic juice (group D: deprivation). The deprivation of pancreatic juice provoked a marked depression in the absorption of glucose (D 67.9 (SEM 27.9) g/10 h, C 437.7 (SEM 39.5) g/10 h, P juice. Insulin production was much lower (by 64%, P juice whereas that of glucagon was not affected.

  16. Effect on phloridzin on net rate of liquid absorption from the pleural space of rabbits.

    Science.gov (United States)

    Zocchi, L; Agostoni, E; Raffaini, A

    1996-11-01

    Previous indirect findings have suggested the occurrence of solute-coupled liquid absorption from the pleural space, consistent with Na(+)-K(+)-ATPase on the interstitial side plus a Na(+)-H+ and CI(-)-HCO3- double exchange on the luminal side of the pleural mesothelium. To assess whether Na(+)-glucose cotransport also operates on the luminal side, the relationship between net rate of liquid absorption from the right pleural space (Jnet) and volume of liquid injected into this space (0.5, 1 or 2 ml) was determined in anaesthetized rabbits during hydrothoraces with phloridzin (10(-3)M) or with phloridzin plus 4-acetamido-4'-isothiocyanatostilbene-2, 2'-disulphonic acid (SITS; 1.5 x 10(-4)M). The relationship obtained during hydrothoraces with phloridzin was displaced downwards by 0.09 ml h-1 relative to that in control hydrothoraces (P pleural mesothelium, operating simultaneously with the double exchange also under physiological conditions.

  17. Subcutaneous insulin infusion: change in basal infusion rate has no immediate effect on insulin absorption rate

    International Nuclear Information System (INIS)

    Hildebrandt, P.; Birch, K.; Jensen, B.M.; Kuehl, C.

    1986-01-01

    Eight insulin-dependent diabetic patients were simultaneously given subcutaneous infusions (1.12 IU/h each) of 125 I-labeled Actrapid insulin in each side of the abdominal wall. After 24 h of infusion, the size of the infused insulin depots was measured by external counting for 5 h. The basal infusion rate was then doubled in one side and halved in the other for the next 4 h. Finally, 1.12 IU/h of insulin was given in both sides of the abdominal wall for an additional 3 h. The changes in the size of the depots were measured, and the absorption rates for each hour were calculated. During the first 5 h of infusion, the depot size was almost constant (approximately 5 IU) with an absorption rate that equaled the infusion rate. Doubling the infusion rate led to a significant increase in depot size, but the absorption rate remained unchanged for the first 3 h, and only thereafter was a significant increase seen. When the infusion rate was reduced to the initial 1.12 IU/h, the absorption rate remained elevated during the next 3 h. Correspondingly, when the infusion rate was decreased, the depot size also decreased, but the absorption rate remained unchanged for the first 3 h. The results show that a change in the basal insulin infusion rate does not lead to any immediate change in the insulin absorption rate. This should be considered when planning an insulin-infusion program that includes alteration(s) in the basal-rate setting

  18. Direct vs. indirect pathway of hepatic glycogen synthesis as a function of glucose infusion rate

    International Nuclear Information System (INIS)

    Bagby, G.J.; Lang, C.H.; Johnson, J.L.; Blakesly, H.L.; Spitzer, J.J.

    1986-01-01

    This study was initiated to determine the influence of the rate of exogenous glucose administration on liver glycogen synthesis by the direct (glucose uptake and incorporation into glycogen) vs the indirect pathway (glucose degradation to 3-carbon intermediates, e.g., lactate, prior to incorporation into glycogen). Catheterized rats were fasted 2 days prior to receiving a 3 hr infusion of glucose at rates of 0 to 230 μmol/min/kg containing tracer [6- 3 H]- and [U- 14 C]-glucose. Plasma glucose (r = 0.80), insulin (r = 0.90) and lactate (r = 0.84) were correlated with glucose infusion rate. The rate of liver glycogen deposition (0.46 +/- 0.03 μmol/min/g) did not differ between a glucose infusion rate of 20 and 230 μmol/min/kg. At the lowest and highest glucose infusion rates hepatic glycogenesis accounted for 87 +/- 6 and 9 +/- 1% of the total glucose load, respectively. The percent contribution of the direct pathways to glycogen deposition ([ 3 H] specific activity in hepatic glycogen/[ 3 H] specific activity in plasma glucose) increased from 16 +/- 3 to 83 +/- 5% from lowest to highest glucose infusion rates (prevailing plasma glucose concentrations: 9 +/- 1 and 21 +/- 2 mM, respectively). The results indicate that the relative contribution of the direct and indirect pathways of glucogen synthesis are dependent upon the glucose load or plasma glucose concentration

  19. Mesenteric blood flow, glucose absorption and blood pressure responses to small intestinal glucose in critically ill patients older than 65 years.

    Science.gov (United States)

    Sim, Jennifer A; Horowitz, M; Summers, M J; Trahair, L G; Goud, R S; Zaknic, A V; Hausken, T; Fraser, J D; Chapman, M J; Jones, K L; Deane, A M

    2013-02-01

    To compare nutrient-stimulated changes in superior mesenteric artery (SMA) blood flow, glucose absorption and glycaemia in individuals older than 65 years with, and without, critical illness. Following a 1-h 'observation' period (t (0)-t (60)), 0.9 % saline and glucose (1 kcal/ml) were infused directly into the small intestine at 2 ml/min between t (60)-t (120), and t (120)-t (180), respectively. SMA blood flow was measured using Doppler ultrasonography at t (60) (fasting), t (90) and t (150) and is presented as raw values and nutrient-stimulated increment from baseline (Δ). Glucose absorption was evaluated using serum 3-O-methylglucose (3-OMG) concentrations during, and for 1 h after, the glucose infusion (i.e. t (120)-t (180) and t (120)-t (240)). Mean arterial pressure was recorded between t (60)-t (240). Data are presented as median (25th, 75th percentile). Eleven mechanically ventilated critically ill patients [age 75 (69, 79) years] and nine healthy volunteers [70 (68, 77) years] were studied. The magnitude of the nutrient-stimulated increase in SMA flow was markedly less in the critically ill when compared with healthy subjects [Δt (150): patients 115 (-138, 367) versus health 836 (618, 1,054) ml/min; P = 0.001]. In patients, glucose absorption was reduced during, and for 1 h after, the glucose infusion when compared with health [AUC(120-180): 4.571 (2.591, 6.551) versus 11.307 (8.447, 14.167) mmol/l min; P AUC(120-240): 26.5 (17.7, 35.3) versus 40.6 (31.7, 49.4) mmol/l min; P = 0.031]. A close relationship between the nutrient-stimulated increment in SMA flow and glucose absorption was evident (3-OMG AUC(120-180) and ∆SMA flow at t (150): r (2) = 0.29; P 65 years, stimulation of SMA flow by small intestinal glucose infusion may be attenuated, which could account for the reduction in glucose absorption.

  20. Orexins control intestinal glucose transport by distinct neuronal, endocrine and direct epithelial pathways. : Orexins regulate intestinal glucose absorption

    OpenAIRE

    Ducroc, Robert; Voisin, Thierry; El Firar, Aadil; Laburthe, Marc

    2007-01-01

    International audience; Objective : Orexins are neuropeptides involved in energy homeostasis. We investigated the effect of orexin A (OxA) and OxB on intestinal glucose transport in the rat. Research Design and Methods : Injection of orexins led to a decrease in the blood glucose level in OGTT. Effects of orexins on glucose entry were analysed in Ussing chamber using the Na+-dependent increase in short-circuit current to quantify jejunal glucose transport. Results & Conclusions : The rapid an...

  1. Distribution of photon absorption rates across the rat retina.

    Science.gov (United States)

    Williams, T P; Webbers, J P; Giordano, L; Henderson, R P

    1998-04-15

    1. An investigation into the distribution of light intensity across the rat retina was carried out on excised, intact rat eyes exposed to Ganzfeld illumination from a helium-neon laser (543 nm). 2. Some of the light entering the eyes exits through the sclera where its intensity can be monitored with an optical 'pick-up' that samples the intensity coming from a small region of external sclera and underlying retina. The spatial resolution of the pick-up is such that it samples light that has passed through ca 2 % of the rods in the rat eye. 3. Some of the laser light is absorbed by the rod pigment, rhodopsin, which gradually bleaches. Bleaching in the retina, in turn, causes an exponential increase in intensity emanating from the sclera. By monitoring this intensity increase, we are able to measure two important parameters in a single bleaching run: the local rhodopsin concentration and the local intensity falling on the rods. 4. With an ocular transmission photometer, we have measured both the local intensity and the local rhodopsin concentration across wide regions of rat retina. Both pigmented and albino rats were studied. 5. The distributions of rhodopsin and intensity were both nearly uniform; consequently, the product, (rhodopsin concentration) x (intensity), was similarly nearly equal across the retina. This means that the initial rate of photon absorption is about the same at all retinal locations. 6. Interpreted in terms of photostasis (the regulation of daily photon catch), this means that the rate of photon absorption is about the same in each rod, viz. 14 400 photons absorbed per rod per second. Since this rate of absorption is sufficient to saturate the rod, one possible purpose of photostasis is to maintain the rod system in a saturated state during daylight hours.

  2. Entry rates and recycling of glucose in buffalo calves fed on urea molasses liquid diet

    Energy Technology Data Exchange (ETDEWEB)

    Varma, A; Singh, U B; Verma, D N; Ranjhan, S K [Indian Veterinary Research Inst., Izatnagar. Div. of Animal Nutrition

    1974-12-01

    Entry rates of glucose have been measured in buffalo calves by using a dual-isotope dilution method based on continuous infusion of (U-/sup 14/C)D-glucose and (6-/sup 3/H)D-glucose into the blood at a precise controlled rate for 540 min. After 5 h a plateau was obtained in the specific radioactivity of the plasma glucose from which glucose synthesis and entry rates were calculated. The average entry rates of glucose were 112 and 145 mg/min measured by /sup 14/C and /sup 3/H labelled glucose respectively. About 23 percent of the glucose carbon was recycled in the pool. The average recycling rate was 33 mg/min.

  3. Entry rates and recycling of glucose in buffalo calves fed on urea molasses liquid diet

    International Nuclear Information System (INIS)

    Varma, Arun; Singh, U.B.; Verma, D.N.; Ranjhan, S.K.

    1974-01-01

    Entry rates of glucose have been measured in buffalo calves by using a dual-isotope dilution method based on continuous infusion of (U- 14 C)D-glucose and (6- 3 H)D-glucose into the blood at a precise controlled rate for 540 min. After 5 h a plateau was obtained in the specific radioactivity of the plasma glucose from which glucose synthesis and entry rates were calculated. The average entry rates of glucose were 112 and 145 mg/min measured by 14 C and 3 H labelled glucose respectively. About 23 percent of the glucose carbon was recycled in the pool. The average recycling rate was 33 mg/min. (author)

  4. Estimation of glucose rate of appearance from cgs and subcutaneous insulin delivery in type 1 diabetes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-08-31

    Method and System for providing estimates of Glucose Rate of Appearance from the intestine (GRA) using continuous glucose sensor measurements (CGS) taken from the subcutaneous of a diabetes patient and the amount of insulin administered to the patient.

  5. Estimation of glucose rate of appearance from cgs and subcutaneous insulin delivery in type 1 diabetes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem; Al-Matouq, Ali Ahmed

    2017-01-01

    Method and System for providing estimates of Glucose Rate of Appearance from the intestine (GRA) using continuous glucose sensor measurements (CGS) taken from the subcutaneous of a diabetes patient and the amount of insulin administered

  6. Binding of navy bean (Phaseolus vulgaris) lectin to the intestinal cells of the rat and its effect on the absorption of glucose

    International Nuclear Information System (INIS)

    Donatucci, D.A.; Liener, I.E.; Gross, C.J.

    1987-01-01

    The main objectives of this investigation were to study the binding of a lectin from navy beans with the epithelial cells of the rat intestine and to assess the effect of such binding on the ability of the intestine to absorb glucose. A Scatchard plot, based on the binding of 125 I-labeled lectin to isolated intestinal epithelial cells, was used to calculate an association constant (Ka) of 15 x 10(6)M-1 and the number of binding sites per cell, 12 x 10(6). Metabolic studies were conducted over a period of 5 d on groups of rats fed raw or autoclaved navy bean flour and casein with or without the purified lectin. Growth, protein digestibility, biological value and net protein utilization were significantly lower in animals that had been fed raw navy bean flour or casein plus lectin than in control groups fed diets containing autoclaved navy bean flour or casein alone. Vascular perfusion was used to measure the rate of uptake of glucose by the intestines of rats that had received the various dietary treatments. The rate of absorption of [ 14 C]glucose by intestines from rats fed raw navy bean flour or casein plus lectin was approximately one-half that of their counterparts fed the autoclaved flour or casein alone. These results provide evidence that the lectin, by virtue of its interference with intestinal absorption, is responsible, at least in part, for the nutritional inferiority of raw navy beans

  7. Effect of petroleum vapors inhalation on intestinal absorption of glucose and some amino acids in the rat

    International Nuclear Information System (INIS)

    Szablicka, E.; Oledzka, R.

    1989-01-01

    The proper intestinal absorption of nutrients, particularly sugars and amino acids, is necessary to keep the organism healthy. It is well known that various toxic compounds present in the environment can have an unfavorable influence. On the other hand it is also known that crude oil which pollutes the aqueous environment affects birds' gastrointestinal tract. Little is known about the influence of petroleum vapors on the gastrointestinal tract of animals and humans. The present study was undertaken to determine the effect of petroleum vapors inhalation on intestinal absorption of some nutrients (glucose, leucine, methionine) in rats

  8. Alteration of carbohydrates metabolism and midgut glucose absorption in Gromphadorhina portentosa after subchronic exposure to imidacloprid and fenitrothion.

    Science.gov (United States)

    Sawczyn, Tomasz; Dolezych, Bogdan; Klosok, Marcin; Augustyniak, Maria; Stygar, Dominika; Buldak, Rafal J; Kukla, Michal; Michalczyk, Katarzyna; Karcz-Socha, Iwona; Zwirska-Korczala, Krystyna

    2012-01-01

    This study was undertaken to test the hypothesis that following exposure to insecticides, changes take place in the metabolism of carbohydrates and absorption in the midgut of insects. The Madagascar hissing cockroach (Gromphadorhina portentosa) was chosen for the experiment as a model organism, due to it being easy to breed and its relatively large alimentary tract, which was important when preparing the microperfusion midgut bioassay. In each group of cockroaches treated with imidacloprid and fenitrothion, absorption of glucose, expressed as the area under the curve (AUC), was elevated compared to the control group. Glucose in the hemolymph of the examined insects was present in a vestigial amount, often below the threshold of determination, so the determinable carbohydrate indices were: hemolymph trehalose concentration and fat body glycogen content. The level of trehalose found in the hemolymph of insects when exposed to fenitrothion, and irrespective of the level of concentration mixed into food, were significantly lower when comparing to the control samples. Imidacloprid acted analogically with one exception at the concentration of 10 mg·kg(-1) dry food where trehalose concentration did not differ from the control values. Coupling with fat body glycogen concentration was less visible and appeared only at the concentrations of 5 and 10 mg imidacloprid·kg(-1) dry food. As described in this study changes in the sugar distribution and midgut glucose absorption indicate that insects cover the increased energy needs induced by insecticides; also at the gastrointestinal tract level. The result indicates that the midgut glucose absorption parameters could be considered as a non-specific biomarker of insecticide toxicity.

  9. Rate of water absorption and proximate analysis of different varieties ...

    African Journals Online (AJOL)

    GREGORY

    2010-12-21

    Dec 21, 2010 ... corn and yellow corn soaked at different temperatures and time duration were determined. Absorption ... found very effective in decreasing faecal transit times. Bressani and Elias (1983). .... evaporation of water. This method ...

  10. Transcriptional responses to glucose at different glycolytic rates in Saccharomyces cerevisiae.

    Science.gov (United States)

    Elbing, Karin; Ståhlberg, Anders; Hohmann, Stefan; Gustafsson, Lena

    2004-12-01

    The addition of glucose to Saccharomyces cerevisiae cells causes reprogramming of gene expression. Glucose is sensed by membrane receptors as well as (so far elusive) intracellular sensing mechanisms. The availability of four yeast strains that display different hexose uptake capacities allowed us to study glucose-induced effects at different glycolytic rates. Rapid glucose responses were observed in all strains able to take up glucose, consistent with intracellular sensing. The degree of long-term responses, however, clearly correlated with the glycolytic rate: glucose-stimulated expression of genes encoding enzymes of the lower part of glycolysis showed an almost linear correlation with the glycolytic rate, while expression levels of genes encoding gluconeogenic enzymes and invertase (SUC2) showed an inverse correlation. Glucose control of SUC2 expression is mediated by the Snf1-Mig1 pathway. Mig1 dephosphorylation upon glucose addition is known to lead to repression of target genes. Mig1 was initially dephosphorylated upon glucose addition in all strains able to take up glucose, but remained dephosphorylated only at high glycolytic rates. Remarkably, transient Mig1-dephosphorylation was accompanied by the repression of SUC2 expression at high glycolytic rates, but stimulated SUC2 expression at low glycolytic rates. This suggests that Mig1-mediated repression can be overruled by factors mediating induction via a low glucose signal. At low and moderate glycolytic rates, Mig1 was partly dephosphorylated both in the presence of phosphorylated, active Snf1, and unphosphorylated, inactive Snf1, indicating that Mig1 was actively phosphorylated and dephosphorylated simultaneously, suggesting independent control of both processes. Taken together, it appears that glucose addition affects the expression of SUC2 as well as Mig1 activity by both Snf1-dependent and -independent mechanisms that can now be dissected and resolved as early and late/sustained responses.

  11. Concurrent duodenal manometric and impedance recording to evaluate the effects of hyoscine on motility and flow events, glucose absorption, and incretin release

    NARCIS (Netherlands)

    Chaikomin, Reawika; Wu, Keng Liang; Doran, Selena; Jones, Karen L.; Smout, Andre J. P. M.; Renooij, Willem; Holloway, Richard H.; Meyer, James H.; Horowitz, Michael; Rayner, Christopher K.

    2007-01-01

    Upper gastrointestinal motor function and incretin hormone secretion are major determinants of postprandial glycemia and insulinemia. However, the impact of small intestinal flow events on glucose absorption and incretin release is poorly defined. Intraluminal impedance monitoring is a novel

  12. Frenkel defect absorption on dislocations and dislocation discharge rate. Modeling determination of the absorption zone

    International Nuclear Information System (INIS)

    Mikhlin, Eh.Ya.

    1988-01-01

    A situation connected with the fact that evaluations of dislocation discharge strength which somehow or other are based on the elasticity theory in the dislocation nucleus or near it, do not lead to results complying with experimental data, is discussed. Bases of the alternative approach to this problem consisting in direct investigation into the process of Frenkel defect absorption on dislocation by its computerized simulation at the microscopic level are also presented. Methods of investigation and results are described using α dislocation in iron-alpha as an example. The concept of zones of vacancy and interstitial atom absorption on dislocation is discussed. It is shown that a spontaneous transition, performed by any of these defects near a dislocation is not always identical to absorption and usually appears to be only a part of a multistage process leading to the defect disappearance. Potential relief characteristics for vacancy movement near the dislocation are found. An area wide enough in a transverse direction is found around the dislocation. Vacncies reaching this area can be easily transported to places of their disappearance. Therefore the vacancy entry to this area is equivalent to the absorption. the procedure of simulating the atomic structure of a crystallite containing a dislocation with a step is described. Positions from which these defects perform spontaneous transitions, reaching the disappearance places are found on the dislocation near the step

  13. Rate of absorption and interfacial area of chlorine into aqueous ...

    African Journals Online (AJOL)

    Due to excellent mass transfer characteristics with energy efficiency jet ejectors can be used in place of conventional countercurrent systems, namely, packed bed contactors as well as venturi scrubbers, cyclones and airlift pumps. The removal of chlorine from certain gases by absorption in aqueous solutions of sodium ...

  14. Glucose Pump Test can be Used to Measure Blood Flow Rate of ...

    African Journals Online (AJOL)

    The aim of study is to determine whether glucose pump test (GPT) is used for surveillance of native AV fistulas by using Doppler US as reference. Methods: In 93 chronic hemodialysis patients with native AV fistula, blood flow rates were measured by Doppler US and GPT. For GPT, glucose was infused to 16 mL/min by ...

  15. Glucose Pump Test can be Used to Measure Blood Flow Rate of ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Blood flow rates of AV fistula can be affected by osmotic and oncotic pressures of blood and arterial blood pressures. Sodium, glucose, hemoglobin, and albumin are significant effectors, created osmotic and oncotic pressures [Table 3]. Blood levels of hemoglobin. (Hb), albumin, sodium (Na), and glucose ...

  16. Glucose phosphorylation is not rate limiting for accumulation of glycogen from glucose in perfused livers from fasted rats

    International Nuclear Information System (INIS)

    Youn, J.H.; Ader, M.; Bergman, R.N.

    1989-01-01

    Incorporation of Glc and Fru into glycogen was measured in perfused livers from 24-h fasted rats using [6-3H]Glc and [U-14C]Fru. For the initial 20 min, livers were perfused with low Glc (2 mM) to deplete hepatic glycogen and were perfused for the following 30 min with various combinations of Glc and Fru. With constant Fru (2 mM), increasing perfusate Glc increased the relative contribution of Glc carbons to glycogen (7.2 +/- 0.4, 34.9 +/- 2.8, and 59.1 +/- 2.7% at 2, 10, and 20 mM Glc, respectively; n = 5 for each). During perfusion with substrate levels seen during refeeding (10 mM Glc, 1.8 mumol/g/min gluconeogenic flux from 2 mM Fru), Fru provided 54.7 +/- 2.7% of the carbons for glycogen, while Glc provided only 34.9 +/- 2.8%, consistent with in vivo estimations. However, the estimated rate of Glc phosphorylation was at least 1.10 +/- 0.11 mumol/g/min, which exceeded by at least 4-fold the glycogen accumulation rate (0.28 +/- 0.04 mumol of glucose/g/min). The total rate of glucose 6-phosphate supply via Glc phosphorylation and gluconeogenesis (2.9 mumol/g/min) exceeded reported in vivo rates of glycogen accumulation during refeeding. Thus, in perfused livers of 24-h fasted rats there is an apparent redundancy in glucose 6-phosphate supply. These results suggest that the rate-limiting step for hepatic glycogen accumulation during refeeding is located between glucose 6-phosphate and glycogen, rather than at the step of Glc phosphorylation or in the gluconeogenic pathway

  17. Determination of sedimentation rates and absorption coefficient of ...

    African Journals Online (AJOL)

    2+ has a higher sedimentation rate of 5.10x10-2 s-1 while Ni2+ has the lowest sedimentation rates of 1.10 x10-3. The rate of sedimentation of the metal carbonates decreased in the order: Zn2+ > Cd2+ > Cu2+ > Co2+ > Ni2+. The order ...

  18. Effects of animal activity on the absorption rate of soils in the ...

    African Journals Online (AJOL)

    The rates of absorption into various microsites in Karoo soils were compared. The absorption of water by hard, bare intershrub soils was significantly increased by the presence of emergence holes of adult cicadas and near nest-mounds of the harvester ant Messor capensis. Both these insects play an important role in ...

  19. Variation in 125I-Insulin absorption and blood glucose concentration

    International Nuclear Information System (INIS)

    Lauritzen, T.; Faber, O.K.; Binder, C.

    1979-01-01

    The absorption of monocomponent porcine 125 I-insulin Monotard and Isophane was studied in six insulin dependent diabetic patients over a period of 12 days. The absorption of insulin was measured as the disappearance of radioactivity from sites of injection. The daily 125 I-insulin doses ranged from 20 to 48 IU between patients. The insulin absorbed varied considerably within and between patients. The range of individual daily absorbed insulin varied from 19 to 104 per cent of the 125 I-insulin dose. A significant correlation (p [de

  20. Hemispherical dominance of glucose metabolic rate in the brain of the 'normal' ageing population

    NARCIS (Netherlands)

    Cutts, DA; Maguire, RP; Leenders, KL; Spyrou, NM

    2004-01-01

    In the 'normal' ageing brain a decrease in the cerebral metabolic rate has been determined across many brain regions. This study determines whether age differences would affect metabolic rates in regions and different hemispheres of the brain. The regional metabolic rate of glucose (rCMRGlu) was

  1. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rumsey, J.M.; Duara, R.; Grady, C.; Rapoport, J.L.; Margolin, R.A.; Rapoport, S.I.; Cutler, N.R.

    1985-05-01

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions.

  2. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    International Nuclear Information System (INIS)

    Rumsey, J.M.; Duara, R.; Grady, C.; Rapoport, J.L.; Margolin, R.A.; Rapoport, S.I.; Cutler, N.R.

    1985-01-01

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions

  3. Astroglial Pentose Phosphate Pathway Rates in Response to High-Glucose Environments

    Directory of Open Access Journals (Sweden)

    Shinichi Takahashi

    2012-02-01

    Full Text Available ROS (reactive oxygen species play an essential role in the pathophysiology of diabetes, stroke and neurodegenerative disorders. Hyperglycaemia associated with diabetes enhances ROS production and causes oxidative stress in vascular endothelial cells, but adverse effects of either acute or chronic high-glucose environments on brain parenchymal cells remain unclear. The PPP (pentose phosphate pathway and GSH participate in a major defence mechanism against ROS in brain, and we explored the role and regulation of the astroglial PPP in response to acute and chronic high-glucose environments. PPP activity was measured in cultured neurons and astroglia by determining the difference in rate of 14CO2 production from [1-14C]glucose and [6-14C]glucose. ROS production, mainly H2O2, and GSH were also assessed. Acutely elevated glucose concentrations in the culture media increased PPP activity and GSH level in astroglia, decreasing ROS production. Chronically elevated glucose environments also induced PPP activation. Immunohistochemical analyses revealed that chronic high-glucose environments induced ER (endoplasmic reticulum stress (presumably through increased hexosamine biosynthetic pathway flux. Nuclear translocation of Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2, which regulates G6PDH (glyceraldehyde-6-phosphate dehydrogenase by enhancing transcription, was also observed in association with BiP (immunoglobulin heavy-chain-binding protein expression. Acute and chronic high-glucose environments activated the PPP in astroglia, preventing ROS elevation. Therefore a rapid decrease in glucose level seems to enhance ROS toxicity, perhaps contributing to neural damage when insulin levels given to diabetic patients are not properly calibrated and plasma glucose levels are not adequately maintained. These findings may also explain the lack of evidence for clinical benefits from strict glycaemic control during the acute phase of stroke.

  4. Astroglial pentose phosphate pathway rates in response to high-glucose environments

    Science.gov (United States)

    Takahashi, Shinichi; Izawa, Yoshikane; Suzuki, Norihiro

    2012-01-01

    ROS (reactive oxygen species) play an essential role in the pathophysiology of diabetes, stroke and neurodegenerative disorders. Hyperglycaemia associated with diabetes enhances ROS production and causes oxidative stress in vascular endothelial cells, but adverse effects of either acute or chronic high-glucose environments on brain parenchymal cells remain unclear. The PPP (pentose phosphate pathway) and GSH participate in a major defence mechanism against ROS in brain, and we explored the role and regulation of the astroglial PPP in response to acute and chronic high-glucose environments. PPP activity was measured in cultured neurons and astroglia by determining the difference in rate of 14CO2 production from [1-14C]glucose and [6-14C]glucose. ROS production, mainly H2O2, and GSH were also assessed. Acutely elevated glucose concentrations in the culture media increased PPP activity and GSH level in astroglia, decreasing ROS production. Chronically elevated glucose environments also induced PPP activation. Immunohistochemical analyses revealed that chronic high-glucose environments induced ER (endoplasmic reticulum) stress (presumably through increased hexosamine biosynthetic pathway flux). Nuclear translocation of Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2), which regulates G6PDH (glyceraldehyde-6-phosphate dehydrogenase) by enhancing transcription, was also observed in association with BiP (immunoglobulin heavy-chain-binding protein) expression. Acute and chronic high-glucose environments activated the PPP in astroglia, preventing ROS elevation. Therefore a rapid decrease in glucose level seems to enhance ROS toxicity, perhaps contributing to neural damage when insulin levels given to diabetic patients are not properly calibrated and plasma glucose levels are not adequately maintained. These findings may also explain the lack of evidence for clinical benefits from strict glycaemic control during the acute phase of stroke. PMID:22300409

  5. Effects of Fat and Protein Preloads on Pouch Emptying, Intestinal Transit, Glycaemia, Gut Hormones, Glucose Absorption, Blood Pressure and Gastrointestinal Symptoms After Roux-en-Y Gastric Bypass.

    Science.gov (United States)

    Nguyen, Nam Q; Debreceni, Tamara L; Burgstad, Carly M; Neo, Melissa; Bellon, Max; Wishart, Judith M; Standfield, Scott; Bartholomeusz, Dylan; Rayner, Chris K; Wittert, Gary; Horowitz, Michael

    2016-01-01

    The aim was to determine the effects of fat and protein preloads on pouch emptying (PE), caecal arrival time (CAT), glucose absorption, blood glucose (BSL), gut hormones, haemodynamics and gastrointestinal (GI) symptoms in subjects who had undergone Roux-en-Y gastric bypass (RYGB) >12 months previously. Ten RYGB subjects were studied on three occasions, in randomised order, receiving 200-ml preloads of either water, fat (30 ml olive oil) or whey protein (55 g), 30 min before a mixed meal. PE, CAT, BSL, plasma 3-O-methyl-D-glucopyranose (3-OMG), insulin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1) and glucagon, blood pressure (BP), heart rate (HR) and GI symptoms were assessed over 270 min. Although fat and protein preloads did not alter PE of either solids or liquids, the CAT of solids, but not liquids, was longer than that after the water preload (fat 68 ± 5 min and protein 71 ± 6 min vs. water 46 ± 5 min; P = 0.02). BSL elevated promptly after the meal on all days (P area under the curve (AUC(0-75 min)), 18.7 ± 18.2 vs. 107.2 ± 30.4 and 76.1 ± 19.3 mmol/L/min; P < 0.05). Compared to water preload, the protein and fat preloads were associated with greater increases in plasma insulin, GLP-1 and glucagon concentrations, a reduction in BP, and greater increases in HR, fullness, bloating and nausea. Plasma 3-OMG levels were lower after the protein than after the water and fat preloads (P < 0.001). Given its effects to attenuate post-prandial glycaemia, reduce intestinal glucose absorption and potentiate the "incretin response", without inducing more adverse post-prandial GI symptom, protein preload may prove clinically useful in RYGB patients and warrant further evaluation, particularly in those with type 2 diabetes (T2DM) and/or dumping syndrome.

  6. Program for PET image alignment: Effects on calculated differences in cerebral metabolic rates for glucose

    International Nuclear Information System (INIS)

    Phillips, R.L.; London, E.D.; Links, J.M.; Cascella, N.G.

    1990-01-01

    A program was developed to align positron emission tomography images from multiple studies on the same subject. The program allowed alignment of two images with a fineness of one-tenth the width of a pixel. The indications and effects of misalignment were assessed in eight subjects from a placebo-controlled double-blind crossover study on the effects of cocaine on regional cerebral metabolic rates for glucose. Visual examination of a difference image provided a sensitive and accurate tool for assessing image alignment. Image alignment within 2.8 mm was essential to reduce variability of measured cerebral metabolic rates for glucose. Misalignment by this amount introduced errors on the order of 20% in the computed metabolic rate for glucose. These errors propagate to the difference between metabolic rates for a subject measured in basal versus perturbed states

  7. Determination of Glucose Utilization Rates in Cultured Astrocytes and Neurons with [14C]deoxyglucose: Progress, Pitfalls, and Discovery of Intracellular Glucose Compartmentation.

    Science.gov (United States)

    Dienel, Gerald A; Cruz, Nancy F; Sokoloff, Louis; Driscoll, Bernard F

    2017-01-01

    2-Deoxy-D-[ 14 C]glucose ([ 14 C]DG) is commonly used to determine local glucose utilization rates (CMR glc ) in living brain and to estimate CMR glc in cultured brain cells as rates of [ 14 C]DG phosphorylation. Phosphorylation rates of [ 14 C]DG and its metabolizable fluorescent analog, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), however, do not take into account differences in the kinetics of transport and metabolism of [ 14 C]DG or 2-NBDG and glucose in neuronal and astrocytic cells in cultures or in single cells in brain tissue, and conclusions drawn from these data may, therefore, not be correct. As a first step toward the goal of quantitative determination of CMR glc in astrocytes and neurons in cultures, the steady-state intracellular-to-extracellular concentration ratios (distribution spaces) for glucose and [ 14 C]DG were determined in cultured striatal neurons and astrocytes as functions of extracellular glucose concentration. Unexpectedly, the glucose distribution spaces rose during extreme hypoglycemia, exceeding 1.0 in astrocytes, whereas the [ 14 C]DG distribution space fell at the lowest glucose levels. Calculated CMR glc was greatly overestimated in hypoglycemic and normoglycemic cells because the intracellular glucose concentrations were too high. Determination of the distribution space for [ 14 C]glucose revealed compartmentation of intracellular glucose in astrocytes, and probably, also in neurons. A smaller metabolic pool is readily accessible to hexokinase and communicates with extracellular glucose, whereas the larger pool is sequestered from hexokinase activity. A new experimental approach using double-labeled assays with DG and glucose is suggested to avoid the limitations imposed by glucose compartmentation on metabolic assays.

  8. The bacterial contamination rate of glucose meter test strips in the hospital setting

    Science.gov (United States)

    Al-Rubeaan, Khalid A.; Saeb, Amr T. M.; AlNaqeb, Dhekra M.; AlQumaidi, Hamed M.; AlMogbel, Turki A.

    2016-01-01

    Objectives: To assess the rate of bacterial contamination of the multi-use vial and single-use packed glucose meter strips, and to identify the type and frequency of various bacterial contamination in different hospital wards. Methods: This prospective observational study was conducted by a team from the Strategic Center for Diabetes Research in 7 general hospitals in the Central region of Saudi Arabia during the period from August to September 2014 to assess the bacterial contamination rate of the unused strips. A total of 10,447 strips were cultured using proper agar media and incubated both aerobically and anaerobically. Results: The total bacterial contamination rate for the multi-use vials glucose strips was 31.7%, while single-use packed strips were not contaminated at all. Ministry of Health hospitals had the highest contamination rates compared with other hospitals. Critical, obstetric, and surgical wards had the highest bacterial isolates number, where most were in the risk group 3 according to the National Institute of Health guidelines. Staphylococcus species were the most common bacteria found. Conclusion: Glucose meter strips should be recognized as a source of bacterial contamination that could be behind serious hospital acquired infections. The hospital infection control team should adopt proper measures to implement protocols for glucose meter cleaning and glucose strips handling. PMID:27570855

  9. Rates and tissue sites of non-insulin- and insulin-mediated glucose uptake in humans

    International Nuclear Information System (INIS)

    Baron, A.D.; Brechtel, G.; Wallace, P.; Edelman, S.V.

    1988-01-01

    In vivo glucose uptake can occur via two mechanisms, namely, insulin-mediated glucose uptake (IMGU) and non-insulin-mediated glucose uptake (NIMGU). Although the principal tissue sites for IMGU are skeletal muscle, the tissue sites for NIMGU at a given serum glucose concentration are not known. To examine this issue, rates of whole body glucose uptake (Rd) were measured at basal and during glucose clamp studies performed at euglycemia (approximately 90 mg/dl) and hyperglycemia (approximately 220 mg/dl) in six lean healthy men. Studies were performed during hyperinsulinemia (approximately 70 microU/ml) and during somatostatin-induced insulinopenia to measure IMGU and NIMGU, respectively. During each study, leg glucose balance (arteriovenous catheter technique) was also measured. With this approach, rates of whole body skeletal muscle IMGU and NIMGU can be estimated, and the difference between overall Rd and skeletal muscle glucose uptake represents non-skeletal muscle Rd. The results indicate that approximately 20% of basal Rd is into skeletal muscle. During insulinopenia approximately 86% of body NIMGU occurs in non-skeletal muscle tissues at euglycemia. When hyperglycemia was created, whole body NIMGU increased from 128 +/- 6 to 213 +/- 18 mg/min (P less than 0.01); NIMGU into non-skeletal muscle tissues was 134 +/- 11 and 111 +/- 6 mg/min at hyperglycemia and euglycemia, respectively, P = NS. Therefore, virtually all the hyperglycemia induced increment in NIMGU occurred in skeletal muscle. During hyperinsulinemia, IMGU in skeletal muscle represented 75 and 95% of body Rd, at euglycemia and hyperglycemia, respectively

  10. Glucose consumption and rate constants for sup 18 F-fluorodeoxyglucose in human gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Masatsune; Kikuchi, Haruhiko; Nagata, Izumi; Yamagata, Sen; Taki, Waro; Yonekura, Yoshiharu; Nishizawa, Sadahiko; Iwasaki, Yasushi; Mukai, Takao [Kyoto Univ. (Japan). Faculty of Medicine

    1990-06-01

    To investigate the value of direct measurement of the rate constants by performing {sup 18}F-labeled fluorodeoxyglucose (FDG) studies of glucose consumption in human gliomas in vivo, a kinetic method with 3- and 4-parameter rate constant models for FDG uptake was used to analyze data from dynamic scans obtained by positron emission tomography after injection of FDG into 14 patients with glioma. The results were compared with those obtained by the autoradiographic method using 3- and 4-parameter rate constant models. There were no significant differences in the glucose consumption calculated by the four different methods both in the gliomas and in the contralateral intact cortex. It was found that the rate constant k4 could be neglected in calculation of glucose consumption in gliomas as well as in the contralateral intact cortex. The rate constant k3, an index of hexokinase function, was higher in malignant gliomas than in benign gliomas and was close to that in the contralateral cortex. This study indicates that the 3-parameter autoradiographic method, which is the most common one used in clinical practice, is reliable for the calculation of glucose consumption in human gliomas. Furthermore, direct measurement of the regional rate constants for FDG by the kinetic method was found to be useful for evaluation of the biochemical and physiological characteristics of human gliomas in vivo. (author).

  11. Glucose consumption and rate constants for 18F-fluorodeoxyglucose in human gliomas

    International Nuclear Information System (INIS)

    Ishikawa, Masatsune; Kikuchi, Haruhiko; Nagata, Izumi; Yamagata, Sen; Taki, Waro; Yonekura, Yoshiharu; Nishizawa, Sadahiko; Iwasaki, Yasushi; Mukai, Takao

    1990-01-01

    To investigate the value of direct measurement of the rate constants by performing 18 F-labeled fluorodeoxyglucose (FDG) studies of glucose consumption in human gliomas in vivo, a kinetic method with 3- and 4-parameter rate constant models for FDG uptake was used to analyze data from dynamic scans obtained by positron emission tomography after injection of FDG into 14 patients with glioma. The results were compared with those obtained by the autoradiographic method using 3- and 4-parameter rate constant models. There were no significant differences in the glucose consumption calculated by the four different methods both in the gliomas and in the contralateral intact cortex. It was found that the rate constant k4 could be neglected in calculation of glucose consumption in gliomas as well as in the contralateral intact cortex. The rate constant k3, an index of hexokinase function, was higher in malignant gliomas than in benign gliomas and was close to that in the contralateral cortex. This study indicates that the 3-parameter autoradiographic method, which is the most common one used in clinical practice, is reliable for the calculation of glucose consumption in human gliomas. Furthermore, direct measurement of the regional rate constants for FDG by the kinetic method was found to be useful for evaluation of the biochemical and physiological characteristics of human gliomas in vivo. (author)

  12. Resistant starch and arabinoxylan augment SCFA absorption, but affect postprandial glucose and insulin responses differently - CORRIGENDUM

    DEFF Research Database (Denmark)

    Ingerslev, Anne Krog; Theil, Peter Kappel; Hedemann, Mette Skou

    2015-01-01

    The effects of increased colonic fermentation of dietary fibres (DF) on net portal flux (NPF) of carbohydrate-derived metabolites (glucose, SCFA and especially butyrate), hormones (insulin, C-peptide, GLP-1, GIP) and NEFA were studied in a healthy catheterised pig model. Six 59 ± 3.8 kg pigs were...... fitted with catheters in the mesenteric artery, the portal and hepatic vein, and a flowprobe around the portal vein and included in a double 3x3 crossover design with three daily feedings (at 9.00, 14.00 and 19.00 hours). Fasting and 5 hours postprandial blood samples were collected after 7 days...... adaptation to each diet. The pigs were fed a low DF western style control diet (WSD) and two high DF diets; an arabinoxylan (AXD) and a resistant starch (RSD) enriched diet. The NPF of insulin was lower (P = 0.04) in AXD fed pigs (4.6 nmol/h) compared to RSD fed pigs (10.5 nmol/h), despite the lowest NPF...

  13. Intensive postoperative glucose control reduces the surgical site infection rates in gynecologic oncology patients.

    Science.gov (United States)

    Al-Niaimi, Ahmed N; Ahmed, Mostafa; Burish, Nikki; Chackmakchy, Saygin A; Seo, Songwon; Rose, Stephen; Hartenbach, Ellen; Kushner, David M; Safdar, Nasia; Rice, Laurel; Connor, Joseph

    2015-01-01

    SSI rates after gynecologic oncology surgery vary from 5% to 35%, but are up to 45% in patients with diabetes mellitus (DM). Strict postoperative glucose control by insulin infusion has been shown to lower morbidity, but not specifically SSI rates. Our project studied continuous postoperative insulin infusion for 24h for gynecologic oncology patients with DM and hyperglycemia with a target blood glucose of controlled with intermittent subcutaneous insulin injections. Group 2 was composed of patients with DM and postoperative hyperglycemia whose blood glucose was controlled by insulin infusion. Group 3 was composed of patients with neither DM nor hyperglycemia. We controlled for all relevant factors associated with SSI. We studied a total of 372 patients. Patients in Group 2 had an SSI rate of 26/135 (19%), similar to patients in Group 3 whose rate was 19/89 (21%). Both were significantly lower than the SSI rate (43/148, 29%) of patients in Group 1. This reduction of 35% is significant (p = 0.02). Multivariate analysis showed an odd ratio = 0.5 (0.28-0.91) in reducing SSI rates after instituting this protocol. Initiating intensive glycemic control for 24h after gynecologic oncology surgery in patients with DM and postoperative hyperglycemia lowers the SSI rate by 35% (OR = 0.5) compared to patients receiving intermittent sliding scale insulin and to a rate equivalent to non-diabetics. Copyright © 2014. Published by Elsevier Inc.

  14. Brain Size and Cerebral Glucose Metabolic Rate in Nonspecific Retardation and Down Syndrome.

    Science.gov (United States)

    Haier, Richard J.; And Others

    1995-01-01

    Brain size and cerebral glucose metabolic rate were determined for 10 individuals with mild mental retardation (MR), 7 individuals with Down syndrome (DS), and 10 matched controls. MR and DS groups both had brain volumes of about 80% compared to controls, with variance greatest within the MR group. (SLD)

  15. Experimental determination of the absorption rate of unattached radon progeny from respiratory tract to blood

    International Nuclear Information System (INIS)

    Butterweck, G.; Schuler, Ch.; Vessl, G.; Mueller, R.; Marsh, J.W.; Thrift, S.; Birchall, A.

    2002-01-01

    An exposure methodology was developed for the determination of the absorption rate of unattached radon progeny deposited in the human respiratory tract to blood. Twenty-one volunteers were exposed in a radon chamber during well-controlled aerosol and radon progeny conditions, with predominantly unattached radon daughters. Special efforts were made to restrict the dose to the volunteers to an absolute maximum of 0.08 mSv. Measurements of radon gas and radon progeny in blood samples of these volunteers indicated absorption half times of 20 min to 60 min. Former determinations, mainly performed with much larger aerosol particles of diameters between 100 nm and 1000 nm, implied absorption half times around 10 h. This indicates that the absorption of radon decay products from ciliated airways into blood is dependent upon particle size and particle composition. (author)

  16. A review of lung-to-blood absorption rates for radon progeny

    International Nuclear Information System (INIS)

    Marsh, J. W.; Bailey, M. R.

    2013-01-01

    The International Commission on Radiological Protection (ICRP) Publication 66 Human Respiratory Tract Model (HRTM) treats clearance of materials from the respiratory tract as a competitive process between absorption into blood and particle transport to the alimentary tract and lymphatics. The ICRP recommended default absorption rates for lead and polonium (Type M) in ICRP Publication 71 but stated that the values were not appropriate for short-lived radon progeny. This paper reviews and evaluates published data from volunteer and laboratory animal experiments to estimate the HRTM absorption parameter values for short-lived radon progeny. Animal studies showed that lead ions have two phases of absorption: ∼10 % absorbed with a half-time of ∼15 min, the rest with a half-time of ∼10 h. The studies also indicated that some of the lead ions were bound to respiratory tract components. Bound fractions, f b , for lead were estimated from volunteer and animal studies and ranged from 0.2 to 0.8. Based on the evaluations of published data, the following HRTM absorption parameter values were derived for lead as a decay product of radon: f r = 0.1, s r = 100 d -1 , s s = 1.7 d -1 , f b = 0.5 and s b = 1.7 d -1 . Effective doses calculated assuming these absorption parameter values instead of a single absorption half-time of 10 h with no binding (as has generally been assumed) are only a few per cent higher. However, as there is some conflicting evidence on the absorption kinetics for radon progeny, dose calculations have been carried out for different sets of absorption parameter values derived from different studies. The results of these calculations are discussed. (authors)

  17. Energy absorption at high strain rate of glass fiber reinforced mortars

    Directory of Open Access Journals (Sweden)

    Fenu Luigi

    2015-01-01

    Full Text Available In this paper, the dynamic behaviour of cement mortars reinforced with glass fibers was studied. The influence of the addition of glass fibers on energy absorption and tensile strength at high strain-rate was investigated. Static tests in compression, in tension and in bending were first performed. Dynamic tests by means of a Modified Hopkinson Bar were then carried out in order to investigate how glass fibers affected energy absorption and tensile strength at high strain-rate of the fiber reinforced mortar. The Dynamic Increase Factor (DIF was finally evaluated.

  18. Age differences in intercorrelations between regional cerebral metabolic rates for glucose

    International Nuclear Information System (INIS)

    Horwitz, B.; Duara, R.; Rapoport, S.I.

    1986-01-01

    Patterns of cerebral metabolic intercorrelations were compared in the resting state in 15 healthy young men (ages 20 to 32 years) and 15 healthy elderly men (ages 64 to 83 years). Controlling for whole-brain glucose metabolism, partial correlation coefficients were determined between pairs of regional cerebral metabolic rates for glucose determined by positron emission tomography using [18F]fluorodeoxyglucose and obtained in 59 brain regions. Compared with the young men, the elderly men had fewer statistically significant correlations, with the most notable reductions observed between the parietal lobe regions, and between the parietal and frontal lobe regions. These results suggest that cerebral functional interactions are reduced in healthy elderly men

  19. Regional cerebral glucose metabolic rate in human sleep assessed by positron emission tomography

    International Nuclear Information System (INIS)

    Buchsbaum, M.S.; Wu, J.; Hazlett, E.; Sicotte, N.; Bunney, W.E. Jr.; Gillin, J.C.

    1989-01-01

    The cerebral metabolic rate of glucose was measured during nighttime sleep in 36 normal volunteers using positron emission tomography and fluorine-18-labeled 2-deoxyglucose (FDG). In comparison to waking controls, subjects given FDG during non-rapid eye movement (NREM) sleep showed about a 23% reduction in metabolic rate across the entire brain. This decrease was greater for the frontal than temporal or occipital lobes, and greater for basal ganglia and thalamus than cortex. Subjects in rapid eye movement (REM) sleep tended to have higher cortical metabolic rates than walking subjects. The cingulate gyrus was the only cortical structure to show a significant increase in glucose metabolic rate in REM sleep in comparison to waking. The basal ganglia were relatively more active on the right in REM sleep and symmetrical in NREM sleep

  20. In Silico Assessment of Literature Insulin Bolus Calculation Methods Accounting for Glucose Rate of Change.

    Science.gov (United States)

    Cappon, Giacomo; Marturano, Francesca; Vettoretti, Martina; Facchinetti, Andrea; Sparacino, Giovanni

    2018-05-01

    The standard formula (SF) used in bolus calculators (BCs) determines meal insulin bolus using "static" measurement of blood glucose concentration (BG) obtained by self-monitoring of blood glucose (SMBG) fingerprick device. Some methods have been proposed to improve efficacy of SF using "dynamic" information provided by continuous glucose monitoring (CGM), and, in particular, glucose rate of change (ROC). This article compares, in silico and in an ideal framework limiting the exposition to possibly confounding factors (such as CGM noise), the performance of three popular techniques devised for such a scope, that is, the methods of Buckingham et al (BU), Scheiner (SC), and Pettus and Edelman (PE). Using the UVa/Padova Type 1 diabetes simulator we generated data of 100 virtual subjects in noise-free, single-meal scenarios having different preprandial BG and ROC values. Meal insulin bolus was computed using SF, BU, SC, and PE. Performance was assessed with the blood glucose risk index (BGRI) on the 9 hours after meal. On average, BU, SC, and PE improve BGRI compared to SF. When BG is rapidly decreasing, PE obtains the best performance. In the other ROC scenarios, none of the considered methods prevails in all the preprandial BG conditions tested. Our study showed that, at least in the considered ideal framework, none of the methods to correct SF according to ROC is globally better than the others. Critical analysis of the results also suggests that further investigations are needed to develop more effective formulas to account for ROC information in BCs.

  1. Chromatographic determination of the rate and extent of absorption of air pollutants by sea water

    International Nuclear Information System (INIS)

    Nikolakaki, S.; Vassilakos, C.; Katsanos, N.A.

    1994-01-01

    A simple chromatographic method is developed to determine the rate constant for expulsion of an air pollutant from water or its diffusion parameter in the liquid, the rate constant for chemical reaction of the pollutant with water, its mass transfer coefficient in the liquid, and the partition coefficient between liquid water and air. From these physicochemical parameters, the absorption rate by sea water and, therefore, the depletion rate of a polluting substance from the air can be calculated, together with the equilibrium state of this absorption. The method has been applied to nitrogen dioxide being absorbed by triple-distilled water and by sea water, at various temperatures. From the temperature variation of the reaction rate constant and of the partition coefficient, the activation energy for the reaction and the differential heat of solution were determined. (orig.)

  2. The absorption and utilization rates for different types of 3H-vitamin A by broiler

    International Nuclear Information System (INIS)

    Cai Huiyi; Zhang Shu

    1992-01-01

    165 newly hatched Arbor Acres broiler chickens were divided into three groups for studying the absorption speed and the utilization rate of different types and doses of 3 H-vitamin A through feeding and metabolizing experiments. The results obtained are as follows: 1. All types of vitamin A could be absorbed by first-week chicken, and water-dispersible vitamin A is the best one. 2. Utilization rates for three types of 3 H-vitamin A were: oil type 80.67%, power type 82.91%, water-dispersible type 89.43%. 3. Chikens absorbed 3 H-vitamin A more quickly when they were 1-3 days old. Moreover, the absorption was mainly performed at the 2-4 hours after the intake of vitamin A. 4. The absorption of vitamin A in intestine was a continuing process lasted about 72 hours, but most of it was absorbed within 24-28 hours

  3. Glucose phosphorylation rate in rat rarietal cortex during normoglycemia, hypoglycemia, acute hyperglycemia, and in diabetes-prone rats

    International Nuclear Information System (INIS)

    Broendsted, H.E.; Gjedde, A.

    1990-01-01

    Cerebral metabolic rate for glucose (CMRglc) was studied in rats using [6- 14 C]glucose. After intravenous injection the radioactivity of the parietal cortex was corrected for loss of labeled CO 2 and divided by the integral of the arterial plasma glucose concentration, determined during tracer circulation. Treatment with insulin, resulting in plasma glucose concentrations less than 2.6 mmol/l, reduced CMRglc to 64% of the values found in control animals. CMRglc did not change in animals with acute hyper-glycemia produced by intraperiotoneal injection of a glucose solution or in diabetes-prone rats with or withour insulin treatment. (author)

  4. Glucose phosphorylation rate in rat parietal cortex during normoglycemia, hypoglycemia, acute hyperglycemia, and in diabetes-prone rats

    Energy Technology Data Exchange (ETDEWEB)

    Broendsted, H.E.; Gjedde, A. (Department of General Physiology and Biophysics, Panum Institute, University of Copenhagen (Denmark))

    1990-01-01

    Cerebral metabolic rate for glucose (CMRglc) was studied in rats using (6-{sup 14}C)glucose. After intravenous injection the radioactivity of the parietal cortex was corrected for loss of labeled CO{sub 2} and divided by the integral of the arterial plasma glucose concentration, determined during tracer circulation. Treatment with insulin, resulting in plasma glucose concentrations less than 2.6 mmol/l, reduced CMRglc to 64% of the values found in control animals. CMRglc did not change in animals with acute hyper-glycemia produced by intraperiotoneal injection of a glucose solution or in diabetes-prone rats with or withour insulin treatment. (author).

  5. Inhibition of glucose intestinal absorption by kaempferol 3-O-α-rhamnoside purified from Bauhinia megalandra leaves.

    Science.gov (United States)

    Rodríguez, Patricia; González-Mujica, Freddy; Bermúdez, Jairo; Hasegawa, Masahisa

    2010-12-01

    Glucose intestinal absorption (GIA) is one of the factors that increase glycemia. Its reduction could be an important factor in decreasing hyperglycemia in diabetic patients. It has been shown that the aqueous extract of Bauhinia megalandra leaves inhibits GIA. In the present study we identified a compound present in the extract of B. megalandra responsible for the biological effect. The methanol extract of B. megalandra leaves was fractionated using different solvents, and high-speed counter-current chromatography yielding two pure compounds identified by (1)H NMR and (13)C NMR as kaempferol 3-O-α-rhamnoside and quercetin 3-O-α-rhamnoside. The first one increased the K(M) without changes in the V(MAX) of GIA. In addition it exerted an additive inhibitory effect, on GIA, when combined with phlorizin. We suggest that kaempferol 3-O-α-rhamnoside is a competitive inhibitor of intestinal SGLT1 cotransporter. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Determination of water absorption rate of palm kernel shells as an ...

    African Journals Online (AJOL)

    Sawdust, for instance, which is about the most commonly used organic pore agent is known to have high water absorption rates. This is in addition to the inability of the user to have it from one grade of wood-hard wood which is preferred. These factors amount to various drawbacks in the insulating refractory bricks produced ...

  7. Time-dependent changes in the contribution of gluconeogenic precursors and glucose to glycogenesis in isolated rate hepatocytes

    International Nuclear Information System (INIS)

    Marden, L.J.; Davidson, A.L.; Arion, W.J.

    1986-01-01

    Hepatocytes from 21-hr fasted rats were incubated for up to 60 min with 10 mM glucose and gluconeogeneic precursors: 4 mM lactate/0.4 mM pyruvate plus 5 mM alanine and 2 mM fructose or 10 mM glutamine. Tracer 3- 3 H,U- 14 C-glucose was added 15 min before terminating the incubations. In all cases, the 3 H and 14 C specific activities of the newly synthesized glycogen increased over time, relative to the specific activities of medium glucose. The percentage of new carbon in glycogen originating from glucose increased from less than 50% in the first 15 min to over 85% after 30 min. Relative to medium glucose, the ratio of 3 H: 14 C in glycogen was about 0.9 through-out the incubations, indicating direct incorporation of glucose into glycogen without significant prior transformation via the pentose pathway or recycling to triose phosphates. Insulin did not stimulate glucose incorporation into glycogen. 3-Mercaptopicolinate decreased the incorporation of precursor carbon into glycogen during incubations with glutamine but not during incubations with fructose and alanine. These data indicate time-dependent and reciprocal changes in rates of glucose-6-P synthesis from gluconeogenic precursors and glucose. Activation of glucokinase may underlie the increased contribution of glucose to glycogenesis. Thus, the relative importance of glucose and gluconeogenic precursors as substrates for glycogenesis directly reflects their respective contributions to the cellular pool of the glucose-6-P

  8. Absorption of subcutaneously infused insulin: influence of the basal rate pulse interval.

    Science.gov (United States)

    Hildebrandt, P; Birch, K; Jensen, B M; Kühl, C; Brange, J

    1985-01-01

    Eight insulin-dependent diabetic patients were given two constant infusions (each 1 IU/h) of 125I-labeled insulin into the abdominal subcutaneous tissue for about 12 h. Insulin was infused in pulses into one side of the abdomen in 6-min intervals (by means of an Auto-Syringe pump) and in the other side of the abdomen, insulin was infused in 1-h intervals (by means of a Medix pump). The size of the subcutaneous depots was continuously measured by counting the radioactivity at the infusion sites. After starting the infusions, the two depots were built up to steady-state levels at the same time and of the same size (approximately 3 IU) and with similar absorption rates. Thus, during basal rate insulin infusion, identical insulin absorption kinetics was achieved, irrespective of a 10-fold difference in the pulse rate.

  9. Measurement of erosion rate by absorption spectroscopy in a Hall thruster

    International Nuclear Information System (INIS)

    Yamamoto, Naoji; Yokota, Shigeru; Matsui, Makoto; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2005-01-01

    The erosion rate of a Hall thruster was estimated with the objective of building a real-time erosion rate monitoring system using a 1 kW class anode layer type Hall thruster. This system aids the understanding of the tradeoff between lifetime and performance. To estimate the flux of the sputtered wall material, the number density of the sputtered iron was measured by laser absorption spectroscopy using an absorption line from ground atomic iron at 371.9935 nm. An ultravioletAl x In y Ga (1-x-y) N diode laser was used as the probe. The estimated number density of iron was 1.1x10 16 m -3 , which is reasonable when compared with that measured by duration erosion tests. The relation between estimated erosion rate and magnetic flux density also agreed with that measured by duration erosion tests

  10. Bile acid sequestration reduces plasma glucose levels in db/db mice by increasing its metabolic clearance rate.

    Directory of Open Access Journals (Sweden)

    Maxi Meissner

    Full Text Available AIMS/HYPOTHESIS: Bile acid sequestrants (BAS reduce plasma glucose levels in type II diabetics and in murine models of diabetes but the mechanism herein is unknown. We hypothesized that sequestrant-induced changes in hepatic glucose metabolism would underlie reduced plasma glucose levels. Therefore, in vivo glucose metabolism was assessed in db/db mice on and off BAS using tracer methodology. METHODS: Lean and diabetic db/db mice were treated with 2% (wt/wt in diet Colesevelam HCl (BAS for 2 weeks. Parameters of in vivo glucose metabolism were assessed by infusing [U-(13C]-glucose, [2-(13C]-glycerol, [1-(2H]-galactose and paracetamol for 6 hours, followed by mass isotopologue distribution analysis, and related to metabolic parameters as well as gene expression patterns. RESULTS: Compared to lean mice, db/db mice displayed an almost 3-fold lower metabolic clearance rate of glucose (p = 0.0001, a ∼300% increased glucokinase flux (p = 0.001 and a ∼200% increased total hepatic glucose production rate (p = 0.0002. BAS treatment increased glucose metabolic clearance rate by ∼37% but had no effects on glucokinase flux nor total hepatic or endogenous glucose production. Strikingly, BAS-treated db/db mice displayed reduced long-chain acylcarnitine content in skeletal muscle (p = 0.0317 but not in liver (p = 0.189. Unexpectedly, BAS treatment increased hepatic FGF21 mRNA expression 2-fold in lean mice (p = 0.030 and 3-fold in db/db mice (p = 0.002. CONCLUSIONS/INTERPRETATION: BAS induced plasma glucose lowering in db/db mice by increasing metabolic clearance rate of glucose in peripheral tissues, which coincided with decreased skeletal muscle long-chain acylcarnitine content.

  11. Bimolecular Rate Constants for FAD-Dependent Glucose Dehydrogenase from Aspergillus terreus and Organic Electron Acceptors.

    Science.gov (United States)

    Tsuruoka, Nozomu; Sadakane, Takuya; Hayashi, Rika; Tsujimura, Seiya

    2017-03-10

    The flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) from Aspergillus species require suitable redox mediators to transfer electrons from the enzyme to the electrode surface for the application of bioelectrical devices. Although several mediators for FAD-GDH are already in use, they are still far from optimum in view of potential, kinetics, sustainability, and cost-effectiveness. Herein, we investigated the efficiency of various phenothiazines and quinones in the electrochemical oxidation of FAD-GDH from Aspergillus terreus . At pH 7.0, the logarithm of the bimolecular oxidation rate constants appeared to depend on the redox potentials of all the mediators tested. Notably, the rate constant of each molecule for FAD-GDH was approximately 2.5 orders of magnitude higher than that for glucose oxidase from Aspergillus sp. The results suggest that the electron transfer kinetics is mainly determined by the formal potential of the mediator, the driving force of electron transfer, and the electron transfer distance between the redox active site of the mediator and the FAD, affected by the steric or chemical interactions. Higher k ₂ values were found for ortho-quinones than for para-quinones in the reactions with FAD-GDH and glucose oxidase, which was likely due to less steric hindrance in the active site in the case of the ortho-quinones.

  12. Bimolecular Rate Constants for FAD-Dependent Glucose Dehydrogenase from Aspergillus terreus and Organic Electron Acceptors

    Directory of Open Access Journals (Sweden)

    Nozomu Tsuruoka

    2017-03-01

    Full Text Available The flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH from Aspergillus species require suitable redox mediators to transfer electrons from the enzyme to the electrode surface for the application of bioelectrical devices. Although several mediators for FAD-GDH are already in use, they are still far from optimum in view of potential, kinetics, sustainability, and cost-effectiveness. Herein, we investigated the efficiency of various phenothiazines and quinones in the electrochemical oxidation of FAD-GDH from Aspergillus terreus. At pH 7.0, the logarithm of the bimolecular oxidation rate constants appeared to depend on the redox potentials of all the mediators tested. Notably, the rate constant of each molecule for FAD-GDH was approximately 2.5 orders of magnitude higher than that for glucose oxidase from Aspergillus sp. The results suggest that the electron transfer kinetics is mainly determined by the formal potential of the mediator, the driving force of electron transfer, and the electron transfer distance between the redox active site of the mediator and the FAD, affected by the steric or chemical interactions. Higher k2 values were found for ortho-quinones than for para-quinones in the reactions with FAD-GDH and glucose oxidase, which was likely due to less steric hindrance in the active site in the case of the ortho-quinones.

  13. Specific absorption rate analysis of broadband mobile antenna with negative index metamaterial

    Science.gov (United States)

    Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2016-03-01

    This paper presents a negative index metamaterial-inspired printed mobile wireless antenna that can support most mobile applications such as GSM, UMTS, Bluetooth and WLAN frequency bands. The antenna consists of a semi-circular patch, a 50Ω microstrip feed line and metamaterial ground plane. The antenna occupies a very small space of 37 × 47 × 0.508 mm3, making it suitable for mobile wireless application. The perceptible novelty shown in this proposed antenna is that reduction of specific absorption rate using the negative index metamaterial ground plane. The proposed antenna reduced 72.11 and 75.53 % of specific absorption rate at 1.8 and 2.4 GHz, respectively.

  14. Quantitative Rates of Brain Glucose Metabolism Distinguish Minimally Conscious from Vegetative State Patients

    DEFF Research Database (Denmark)

    Stender, Johan; Kupers, Ron; Rodell, Anders

    2015-01-01

    of these patients. However, no quantitative comparisons of cerebral glucose metabolism in VS/UWS and MCS have yet been reported. We calculated the regional and whole-brain CMRglc of 41 patients in the states of VS/UWS (n=14), MCS (n=21) or emergence from MCS (EMCS, n=6), and healthy volunteers (n=29). Global......The differentiation of the vegetative or unresponsive wakefulness syndrome (VS/UWS) from the minimally conscious state (MCS) is an important clinical issue. The cerebral metabolic rate of glucose (CMRglc) declines when consciousness is lost, and may reveal the residual cognitive function...... these results reveal a significant correlation between whole-brain energy metabolism and level of consciousness, suggesting that quantitative values of CMRglc reveal consciousness in severely brain-injured patients.Journal of Cerebral Blood Flow & Metabolism advance online publication, 8 October 2014; doi:10...

  15. Enhanced specific absorption rate of bi-magnetic nanoparticles for heating applications

    Energy Technology Data Exchange (ETDEWEB)

    Hammad, Mohaned; Hempelmann, Rolf, E-mail: r.hempelmann@mx.uni-saarland.de

    2017-02-15

    Truncated octahedron bi-magnetic core/shell nanoparticles of Zn{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}@Zn{sub 0.4}Mn{sub 0.6}Fe{sub 2}O{sub 4} with different size distributions have been synthesized, and their structural and magnetic properties have been studied. The structure and morphology of the core/shell nanostructures were established by using X-ray diffraction, and transmission electron microscopy. Dark field-TEM and X-ray photoelectron spectroscopy results confirmed the formation of bi-magnetic core/shell nanoparticles. The synthesized nanoparticles are superparamagnetic at room temperature. The Curie temperature increases with the increase of particle size from 360 K to 394 K. The experimental results showed that core/shell nanoparticles have a higher specific absorption rate compared to the core ones. These nanoparticles are interfacial exchange coupled between hard and soft magnetic phases. We demonstrated that the specific absorption rate could be tuned by the concentration of precursor and the synthesis time. - Highlights: • Zn{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}@Zn{sub 0.4}Mn{sub 0.6}Fe{sub 2}O{sub 4} nanoparticles were synthesized by seed-mediated growth method. • Exchange-coupling between magnetic hard and soft phase of the magnetic nanoparticles affects the specific absorption rate. • The specific absorption rate could be tuned by the concentration of precursor and the synthesis time. • An increase of the core/shell magnetic nanoparticles size resulted in the increase of Curie temperature.

  16. Specific absorption rate determination of magnetic nanoparticles through hyperthermia measurements in non-adiabatic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Coïsson, M. [INRIM, strada delle Cacce 91, 10135 Torino (Italy); Barrera, G. [INRIM, strada delle Cacce 91, 10135 Torino (Italy); University of Torino, Chemistry Department, via P. Giuria 7, 10125 Torino (Italy); Celegato, F.; Martino, L.; Vinai, F. [INRIM, strada delle Cacce 91, 10135 Torino (Italy); Martino, P. [Politronica srl, via Livorno 60, 10144 Torino (Italy); Ferraro, G. [Center for Space Human Robotics, Istituto Italiano di Tecnologia - IIT, corso Trento 21, 10129 Torino (Italy); Tiberto, P. [INRIM, strada delle Cacce 91, 10135 Torino (Italy)

    2016-10-01

    An experimental setup for magnetic hyperthermia operating in non-adiabatic conditions is described. A thermodynamic model that takes into account the heat exchanged by the sample with the surrounding environment is developed. A suitable calibration procedure is proposed that allows the experimental validation of the model. Specific absorption rate can then be accurately determined just from the measurement of the sample temperature at the equilibrium steady state. The setup and the measurement procedure represent a simplification with respect to other systems requiring calorimeters or crucial corrections for heat flow. Two families of magnetic nanoparticles, one superparamagnetic and one characterised by larger sizes and static hysteresis, have been characterised as a function of field intensity, and specific absorption rate and intrinsic loss power have been obtained. - Highlights: • Development and thermodynamic modelling of a hyperthermia setup operating in non-adiabatic conditions. • Calibration of the experimental setup and validation of the model. • Accurate measurement of specific absorption rate and intrinsic loss power in non-adiabatic conditions.

  17. Correlation between TCA cycle flux and glucose uptake rate during respiro-fermentative growth of Saccharomyces cerevisiae.

    Science.gov (United States)

    Heyland, Jan; Fu, Jianan; Blank, Lars M

    2009-12-01

    Glucose repression of the tricarboxylic acid (TCA) cycle in Saccharomyces cerevisiae was investigated under different environmental conditions using (13)C-tracer experiments. Real-time quantification of the volatile metabolites ethanol and CO(2) allowed accurate carbon balancing. In all experiments with the wild-type, a strong correlation between the rates of growth and glucose uptake was observed, indicating a constant yield of biomass. In contrast, glycerol and acetate production rates were less dependent on the rate of glucose uptake, but were affected by environmental conditions. The glycerol production rate was highest during growth in high-osmolarity medium (2.9 mmol g(-1) h(-1)), while the highest acetate production rate of 2.1 mmol g(-1) h(-1) was observed in alkaline medium of pH 6.9. Under standard growth conditions (25 g glucose l(-1) , pH 5.0, 30 degrees C) S. cerevisiae had low fluxes through the pentose phosphate pathway and the TCA cycle. A significant increase in TCA cycle activity from 0.03 mmol g(-1) h(-1) to about 1.7 mmol g(-1) h(-1) was observed when S. cerevisiae grew more slowly as a result of environmental perturbations, including unfavourable pH values and sodium chloride stress. Compared to experiments with high glucose uptake rates, the ratio of CO(2) to ethanol increased more than 50 %, indicating an increase in flux through the TCA cycle. Although glycolysis and the ethanol production pathway still exhibited the highest fluxes, the net flux through the TCA cycle increased significantly with decreasing glucose uptake rates. Results from experiments with single gene deletion mutants partially impaired in glucose repression (hxk2, grr1) indicated that the rate of glucose uptake correlates with this increase in TCA cycle flux. These findings are discussed in the context of regulation of glucose repression.

  18. Absolute absorption cross-section and photolysis rate of I2

    Directory of Open Access Journals (Sweden)

    A. Saiz-Lopez

    2004-01-01

    Full Text Available Following recent observations of molecular iodine (I2 in the coastal marine boundary layer (MBL (Saiz-Lopez and Plane, 2004, it has become important to determine the absolute absorption cross-section of I2 at reasonably high resolution, and also to evaluate the rate of photolysis of the molecule in the lower atmosphere. The absolute absorption cross-section (σ of gaseous I2 at room temperature and pressure (295K, 760Torr was therefore measured between 182 and 750nm using a Fourier Transform spectrometer at a resolution of 4cm-1 (0.1nm at λ=500nm. The maximum absorption cross-section in the visible region was observed at λ=533.0nm to be σ=(4.24±0.50x10-18cm2molecule-1. The spectrum is available as supplementary material accompanying this paper. The photo-dissociation rate constant (J of gaseous I2 was also measured directly in a solar simulator, yielding J(I2=0.12±0.03s-1 for the lower troposphere. This is in excellent agreement with the value of 0.12±0.015s-1 calculated using the measured absorption cross-section, terrestrial solar flux for clear sky conditions and assuming a photo-dissociation yield of unity. A two-stream radiation transfer model was then used to determine the variation in photolysis rate with solar zenith angle (SZA, from which an analytic expression is derived for use in atmospheric models. Photolysis appears to be the dominant loss process for I2 during daytime, and hence an important source of iodine atoms in the lower atmosphere.

  19. Hemispherical dominance of glucose metabolic rate in the brain of the 'normal' ageing population

    International Nuclear Information System (INIS)

    Cutts, D.A.; Spyrou, N.M.

    2004-01-01

    In the 'normal' ageing brain a decrease in the cerebral metabolic rate has been determined across many brain regions. It is determined whether age differences would affect metabolic rates in regions and different hemispheres of the brain. The regional metabolic rate of glucose (rCMRGlu) was examined in a group of 72 subjects, ages 22 to 82 years, with 36 regions of interest chosen from both hemispheres of the cortex, midbrain and cerebellum. To determine metabolic rates the in-vivo technique of positron emission tomography (PET) was employed. Three age groups were chosen to compare hemispherical differences. In both young and intermediate age groups the left hemisphere had higher rCMRGlu values than those of the right for the majority of regions with, although less pronounced in the intermediate group. Importantly, the older age group displayed little difference between hemispheres. (author)

  20. [Correlation between resting heart rate and blood glucose level in elderly patients with coronary heart disease and diabetes mellitus].

    Science.gov (United States)

    Liang, Dong-Liang; Li, Xiao-Ying; Wang, Lin; Xu, Hao; Tuo, Xi-Ping; Jian, Zai-Jin; Wang, Xiao-Na; Yun, Ji-Li; Zhang, Xu; Wang, Si-Yue

    2016-05-01

    To explore the correlation between resting heart rate (RHR) and blood glucose level in elderly patients with coronary heart disease (CHD) complicated by diabetes mellitus. Between April and July, 2011, a total of 1336 outpatients over 60 years of age recruited from 165 hospitals were asked to complete a questionnaire and received blood glucose and RHR examination. According to baseline RHR, the patients were divided into 3 groups with HRH blood glucose control rate. HbA1c levels in the total, male and female patients differed significantly among the 3 groups (F=15.436, 15.436, and 24.270, respectively, PBlood glucose control rate in the total, male and female patients also differed significantly among the 3 groups (χ(2)=13.471, 6.752, and 6.522, respectively, Pblood glucose control failure of 1.99 (95% CI: 1.23-2.37, Pblood glucose level, and an increased RHR is associated with an increased risk of poor blood glucose control. Rigorous RHR control in such high-risk patients may prove beneficial for both blood glucose control and secondary prevention of CHD.

  1. New constraints in absorptive capacity and the optimum rate of petroleum output

    Energy Technology Data Exchange (ETDEWEB)

    El Mallakh, R

    1980-01-01

    Economic policy in four oil-producing countries is analyzed within a framework that combines a qualitative assessment of the policy-making process with an empirical formulation based on historical and current trends in these countries. The concept of absorptive capacity is used to analyze the optimum rates of petroleum production in Iran, Iraq, Saudi Arabia, and Kuwait. A control solution with an econometric model is developed which is then modified for alternative development strategies based on analysis of factors influencing production decisions. The study shows the consistencies and inconsistencies between the goals of economic growth, oil production, and exports, and the constraints on economic development. Simulation experiments incorporated a number of the constraints on absorptive capacity. Impact of other constraints such as income distribution and political stability is considered qualitatively. (DLC)

  2. Quantitative autoradiography of 14C-D-glucose metabolism of normal and traumatized rat brain using micro-absorption photometry

    International Nuclear Information System (INIS)

    Bonorden, S.

    1980-01-01

    It could be shown using 14 C-glucose as energy-providing substrate for brain tissue metabolism that for bolus type application a retarded and even channelling of the substrate into the metabolic process takes place. The presence of tracer in the tissue was established using autoradiography. A linear correlation between the amount of tissue-incorporated 14 C section thickness and exposure time could be established by means of densitometric measurement of brain sections of various thicknesses, by applying various 14 C-activities and by different exposure times. From these correlations direct conclusions may be made regarding the specific activity of the tissue provided that exposure time and section thickness of the sample are known. Comparative studies between cortex and narrow and between traumatized and non-traumatized brain tissue show that the rate of metabolism in brain cortex is markedly higher than in the marrow and that 14 C-incorporation is higher in traumatized tissue than in non-traumatized tissue. Whilst the difference in rate of metabolism between brain cortex and marrow can be clearly related to the differing cell count/unit surface area for cortex and marrow, the different energy conversion rates for functionally damaged and normal brain tissue is a specific characteristic of injury. Apart from the fact that an increased 14 C-deposition is in no way indicative of an increased metabolic activity, the possibility of quantifying 14 C-tissue content provides a basis for estimating therapeutic effects e.g. in the treatment of trauma-caused brain edema. (orig.) [de

  3. Optimization between heating load and entropy-production rate for endoreversible absorption heat-transformers

    International Nuclear Information System (INIS)

    Sun Fengrui; Qin Xiaoyong; Chen Lingen; Wu Chih

    2005-01-01

    For an endoreversible four-heat-reservoir absorption heat-transformer cycle, for which a linear (Newtonian) heat-transfer law applies, an ecological optimization criterion is proposed for the best mode of operation of the cycle. This involves maximizing a function representing the compromise between the heating load and the entropy-production rate. The optimal relation between the ecological criterion and the COP (coefficient of performance), the maximum ecological criterion and the corresponding COP, heating load and entropy production rate, as well as the ecological criterion and entropy-production rate at the maximum heating load are derived using finite-time thermodynamics. Moreover, compared with the heating-load criterion, the effects of the cycle parameters on the ecological performance are studied by numerical examples. These show that achieving the maximum ecological criterion makes the entropy-production rate decrease by 77.0% and the COP increase by 55.4% with only 27.3% heating-load losses compared with the maximum heating-load objective. The results reflect that the ecological criterion has long-term significance for optimal design of absorption heat-transformers

  4. Enhancement of glomerular filtration rate and renal plasma flow by oral glucose load in well controlled insulin-dependent diabetics

    DEFF Research Database (Denmark)

    Sandahl Christiansen, J; Christensen, C K; Hermansen, K

    1986-01-01

    Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured in 27 patients with uncomplicated insulin-dependent diabetes (IDDM) before and after an oral glucose load of 1.1 g glucose/kg body wt. In the 18 patients showing near-normoglycaemia (blood glucose less than or equal to 8....... No changes in blood pressure or urinary albumin excretion rates took place in either group. The reduction in plasma protein and in plasma growth hormone concentration were similar in the two groups. No change was seen in plasma arginine vasopressin concentration. There was no difference in the qualitative...

  5. INTERSTELLAR METASTABLE HELIUM ABSORPTION AS A PROBE OF THE COSMIC-RAY IONIZATION RATE

    International Nuclear Information System (INIS)

    Indriolo, Nick; McCall, Benjamin J.; Hobbs, L. M.; Hinkle, K. H.

    2009-01-01

    The ionization rate of interstellar material by cosmic rays has been a major source of controversy, with different estimates varying by three orders of magnitude. Observational constraints of this rate have all depended on analyzing the chemistry of various molecules that are produced following cosmic-ray ionization, and in many cases these analyses contain significant uncertainties. Even in the simplest case (H + 3 ), the derived ionization rate depends on an (uncertain) estimate of the absorption path length. In this paper, we examine the feasibility of inferring the cosmic-ray ionization rate using the 10830 A absorption line of metastable helium. Observations through the diffuse clouds toward HD 183143 are presented, but yield only an upper limit on the metastable helium column density. A thorough investigation of He + chemistry reveals that only a small fraction of He + will recombine into the triplet state and populate the metastable level. In addition, excitation to the triplet manifold of helium by secondary electrons must be accounted for as it is the dominant mechanism which produces He* in some environments. Incorporating these various formation and destruction pathways, we derive new equations for the steady state abundance of metastable helium. Using these equations in concert with our observations, we find ζ He -15 s -1 , an upper limit about 5 times larger than the ionization rate previously inferred for this sight line using H + 3 . While observations of interstellar He* are extremely difficult at present, and the background chemistry is not nearly as simple as previously thought, potential future observations of metastable helium would provide an independent check on the cosmic-ray ionization rate derived from H + 3 in diffuse molecular clouds, and, perhaps more importantly, allow the first direct measurements of the ionization rate in diffuse atomic clouds.

  6. Quantitative rates of brain glucose metabolism distinguish minimally conscious from vegetative state patients.

    Science.gov (United States)

    Stender, Johan; Kupers, Ron; Rodell, Anders; Thibaut, Aurore; Chatelle, Camille; Bruno, Marie-Aurélie; Gejl, Michael; Bernard, Claire; Hustinx, Roland; Laureys, Steven; Gjedde, Albert

    2015-01-01

    The differentiation of the vegetative or unresponsive wakefulness syndrome (VS/UWS) from the minimally conscious state (MCS) is an important clinical issue. The cerebral metabolic rate of glucose (CMRglc) declines when consciousness is lost, and may reveal the residual cognitive function of these patients. However, no quantitative comparisons of cerebral glucose metabolism in VS/UWS and MCS have yet been reported. We calculated the regional and whole-brain CMRglc of 41 patients in the states of VS/UWS (n=14), MCS (n=21) or emergence from MCS (EMCS, n=6), and healthy volunteers (n=29). Global cortical CMRglc in VS/UWS and MCS averaged 42% and 55% of normal, respectively. Differences between VS/UWS and MCS were most pronounced in the frontoparietal cortex, at 42% and 60% of normal. In brainstem and thalamus, metabolism declined equally in the two conditions. In EMCS, metabolic rates were indistinguishable from those of MCS. Ordinal logistic regression predicted that patients are likely to emerge into MCS at CMRglc above 45% of normal. Receiver-operating characteristics showed that patients in MCS and VS/UWS can be differentiated with 82% accuracy, based on cortical metabolism. Together these results reveal a significant correlation between whole-brain energy metabolism and level of consciousness, suggesting that quantitative values of CMRglc reveal consciousness in severely brain-injured patients.

  7. Lithium iron phosphate with high-rate capability synthesized through hydrothermal reaction in glucose solution

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Guangchuan; Wang, Li; Ou, Xiuqin; Zhao, Xia; Xu, Shengzhao [Institute of Power Source and Ecomaterials Science, Box 1055, Hebei University of Technology, 300130 Tianjin (China)

    2008-10-01

    Carbon-coated lithium iron phosphate (LiFePO{sub 4}/C) was hydrothermally synthesized from commercial LiOH, FeSO{sub 4} and H{sub 3}PO{sub 4} as raw materials and glucose as carbon precursor in aqueous solution at 180 C for 6 h followed by being fired at 750 C for 6 h. The samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and constant current charge-discharge cycling test. The results show that the synthesized powders are in situ coated with carbon precursor produced from glucose. At ambient temperature (25{+-}2 C), the specific discharge capacities are 154 mAh g{sup -1} at 0.2C and 136 mAh g{sup -1} at 5 C rate, and the cycling capacity retention rate reaches 98% over 90 cycles. The excellent electrochemical performance can be correlated with the in situ formation of carbon precursor/carbon, thus leading to the even distribution of carbon and the enhancement of conductibility of individual grains. (author)

  8. Measurement of specific heat and specific absorption rate by nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Gultekin, David H., E-mail: david.gultekin@aya.yale.edu [Department of Electrical Engineering, Yale University, New Haven, CT 06520 (United States); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065 (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065 (United States); Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232 (United States); Gore, John C. [Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232 (United States); Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37232 (United States); Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37232 (United States); Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232 (United States)

    2010-05-20

    We evaluate a nuclear magnetic resonance (NMR) method of calorimetry for the measurement of specific heat (c{sub p}) and specific absorption rate (SAR) in liquids. The feasibility of NMR calorimetry is demonstrated by experimental measurements of water, ethylene glycol and glycerol using any of three different NMR parameters (chemical shift, spin-spin relaxation rate and equilibrium nuclear magnetization). The method involves heating the sample using a continuous wave laser beam and measuring the temporal variation of the spatially averaged NMR parameter by non-invasive means. The temporal variation of the spatially averaged NMR parameter as a function of thermal power yields the ratio of the heat capacity to the respective nuclear thermal coefficient, from which the specific heat can be determined for the substance. The specific absorption rate is obtained by subjecting the liquid to heating by two types of radiation, radiofrequency (RF) and near-infrared (NIR), and by measuring the change in the nuclear spin phase shift by a gradient echo imaging sequence. These studies suggest NMR may be a useful tool for measurements of the thermal properties of liquids.

  9. Adding glucose to food and solutions to enhance fructose absorption is not effective in preventing fructose-induced functional gastrointestinal symptoms: randomised controlled trials in patients with fructose malabsorption.

    Science.gov (United States)

    Tuck, C J; Ross, L A; Gibson, P R; Barrett, J S; Muir, J G

    2017-02-01

    In healthy individuals, the absorption of fructose in excess of glucose in solution is enhanced by the addition of glucose. The present study aimed to assess the effects of glucose addition to fructose or fructans on absorption patterns and genesis of gastrointestinal symptoms in patients with functional bowel disorders. Randomised, blinded, cross-over studies were performed in healthy subjects and functional bowel disorder patients with fructose malabsorption. The area-under-the-curve (AUC) was determined for breath hydrogen and symptom responses to: (i) six sugar solutions (fructose in solution) (glucose; sucrose; fructose; fructose + glucose; fructan; fructan + glucose) and (ii) whole foods (fructose in foods) containing fructose in excess of glucose given with and without additional glucose. Intake of fermentable short chain carbohydrates (FODMAPs; fermentable, oligo-, di-, monosaccharides and polyols) was controlled. For the fructose in solution study, in 26 patients with functional bowel disorders, breath hydrogen was reduced after glucose was added to fructose compared to fructose alone [mean (SD) AUC 92 (107) versus 859 (980) ppm 4 h -1 , respectively; P = 0.034). Glucose had no effect on breath hydrogen response to fructans (P = 1.000). The six healthy controls showed breath hydrogen patterns similar to those with functional bowel disorders. No differences in symptoms were experienced with the addition of glucose, except more nausea when glucose was added to fructose (P = 0.049). In the fructose in foods study, glucose addition to whole foods containing fructose in excess of glucose in nine patients with functional bowel disorders and nine healthy controls had no significant effect on breath hydrogen production or symptom response. The absence of a favourable response on symptoms does not support the concomitant intake of glucose with foods high in either fructose or fructans in patients with functional bowel disorders. © 2016 The British Dietetic

  10. Influence of temperature on water and aqueous glucose absorption spectra in the near- and mid-infrared regions at physiologically relevant temperatures

    DEFF Research Database (Denmark)

    Jensen, P.S.; Bak, J.; Andersson-Engels, S.

    2003-01-01

    transmission cell controlled within 0.02 degreesC. Pathlengths of 50 mum and 0.4 mm were used in the mid- and near-infrared spectral region, respectively. Difference spectra were used to determine the effect of temperature on the water spectra quantitatively. These spectra were obtained by subtracting the 37...... degreesC water spectrum from the spectra measured at other temperatures. The difference spectra reveal that the effect of temperature is highest in the vicinity of the strong absorption bands, with a number of isosbestic points with no temperature dependence and relatively flat plateaus in between......Near- and mid-infrared absorption spectra of pure water and aqueous 1.0 g/dL glucose solutions in the wavenumber range 8000-950 cm(-1) were measured in the temperature range 30-42 C in steps of 2 degreesC. Measurements were carried out with an FT-IR spectrometer and a variable pathlength...

  11. Elementary reaction rate measurements at high temperatures by tunable-laser flash-absorption

    Energy Technology Data Exchange (ETDEWEB)

    Hessler, J.P. [Argonne National Laboratory, IL (United States)

    1993-12-01

    The major objective of this program is to measure thermal rate coefficients and branching ratios of elementary reactions. To perform these measurements, the authors constructed an ultrahigh-purity shock tube to generate temperatures between 1000 and 5500 K. The tunable-laser flash-absorption technique is used to measure the rate of change of the concentration of species which absorb below 50,000 cm{sup {minus}1} e.g.: OH, CH, and CH{sub 3}. This technique is being extended into the vacuum-ultraviolet spectral region where one can measure atomic species e.g.: H, D, C, O, and N; and diatomic species e.g.: O{sub 2}, CO, and OH.

  12. Effects of Vildagliptin and Metformin on Blood Pressure and Heart Rate Responses to Small Intestinal Glucose in Type 2 Diabetes.

    Science.gov (United States)

    Wu, Tongzhi; Trahair, Laurence G; Little, Tanya J; Bound, Michelle J; Zhang, Xiang; Wu, Hang; Sun, Zilin; Horowitz, Michael; Rayner, Christopher K; Jones, Karen L

    2017-05-01

    To evaluate effects of vildagliptin and metformin on blood pressure (BP) and heart rate (HR) responses to intraduodenal (ID) glucose in diet-controlled type 2 diabetes. Study A compared vildagliptin (50 mg) and placebo, given 60 min before a 120-min ID glucose infusion at 2 or 4 kcal/min (ID2 or ID4) in 16 patients. Study B compared metformin (850 mg) and placebo, given 30 min before ID2 over 120 min in 9 patients. Systolic ( P = 0.002) and diastolic ( P vildagliptin compared with placebo, without interaction between vildagliptin and the glucose infusion rate. In contrast, HR was greater after metformin than placebo ( P Vildagliptin reduces BP and increases HR, whereas metformin increases HR without affecting BP during ID glucose infusion in type 2 diabetes. These distinct cardiovascular profiles during enteral nutrient exposure may have implications for postprandial hypotension. © 2017 by the American Diabetes Association.

  13. EVALUATION OF THE STRUCTURAL FUNDS ABSORPTION RATE BY MEANS OF THE HERMIN MODEL

    Directory of Open Access Journals (Sweden)

    Opritescu Elena Madalina

    2012-07-01

    Full Text Available The main objective of this article is to highlight the main method that could quantify the impact of the structural funds on the Gross Domestic Product. I also presented the regional disparities situation and the European funds absorption rate. The HERMIN model has been designed considering the evolution of macro-variables throughout transition and pre-accession process, as well as out of the need to analyze the gradual alignment of Romania’s economic policies to those of EU. The fact that, initially, the HERMIN model was designed for the European Union’s less developed economies represented the cornerstone in choosing it, as it was the case for Romania, too. However, the quantitative evaluation must always be accompanied by a qualitative evaluation, in order to comprise factors which cannot be measured by the econometrical modeling. For this purpose, when the results of econometrical model based evaluation are used, it is important to be aware of the fact that models simplify reality, no matter the impressive mathematical calculations they employ. Also, we must not omit the fact that Romania’s major development needs and the current economic context imperatively demand a high as possible level of structural funds absorption, as well as their efficient use, meant to generate a significant impact at a national, regional and local level. One of the main instruments employed to sustain economic growth, while also reducing disparities between regions is represented by the structural funds. These funds, consisting in financial contributions of the member states, according to their level of development, are redistributed in compliance with an extremely complex regulating and procedural frame, to those EU states of regions which are fallen behind from a social and economical development perspective Nevertheless, when absorption capacity of a member state is evaluated, the used percentage from the allocated funds is not the only

  14. Local cerebral metabolic rate of glucose (lCMRGlc) in treated and untreated patients with Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Rougemont, D; Baron, J C; Collard, P; Bustany, P; Comar, D; Agid, Y

    1983-06-01

    Local cerebral metabolic rate of glucose (lCMRGlc) was measured twice, using positron emission tomography and /sup 18/F-Fluoro-2-deoxy-D-glucose (/sup 18/FDG), in 4 patients with Parkinson disease, first unmedicated and then treated with L-DOPA. Despite a dramatic clinical improvement, no significant changes in lCMRGlc could be detected. Moreover, no reproducible differences of lCMRGlc were found between patients with Parkinson disease and with normal brain.

  15. Local cerebral metabolic rate of glucose (lCMRGlc) in treated and untreated patients with Parkinson's disease

    International Nuclear Information System (INIS)

    Rougemont, D.; Baron, J.C.; Collard, P.; Bustany, P.; Comar, D.; Agid, Y.

    1983-06-01

    Local cerebral metabolic rate of glucose (lCMRGlc) was measured twice, using positron emission tomography and 18 F-Fluoro-2-deoxy-D-glucose ( 18 FDG), in 4 patients with Parkinson disease, first unmedicated and then treated with L-DOPA. Despite a dramatic clinical improvement, no significant changes in lCMRGlc could be detected. Moreover, no reproducible differences of lCMRGlc were found between patients with Parkinson disease and with normal brain

  16. Absorption of carbon dioxide and isotope exchange rate of carbon in a reaction system between carbon dioxide and carbamic acid

    International Nuclear Information System (INIS)

    Takeshita, Kenji; Kitamoto, Asashi

    1985-01-01

    The performance of isotope separation of carbon-13 by chemical exchange between carbon dioxide and carbamic acid was studied. The working fluid used in the study was a solution of DNBA, (C 4 H 9 ) 2 NH and n-octane mixture. Factors related to the isotope exchange rate were measured, such as the absorption rate of carbon dioxide into the solution of DNBA and n-octane, the isotope exchange rate and the separation factor in the reaction between CO 2 and carbamic acid. The absorption of CO 2 into the working fluid was the sum of chemical absorption by DNBA and physical absorption by n-octane. The absorption of carbon dioxide into the working fluid was negligible at temperatures over 90 0 C, but increased gradually at lower temperatures. Carbon dioxide was absorbed into DNBA by chemical absorption, and DNBA was converted to carbamic acid by the reaction. The reaction for synthesis and decomposition of carbamic acid was reversible. The separation factor in equilibrium reached a large value at lower temperatures. The isotope exchange rate between gas and liquid was proportional to the product of the concentration of carbamic acid and the concentration of CO 2 by physical absorption. The isotope separation of carbon by chemical exchange reaction is better operated under the conditions of lower temperature and higher pressure. (author)

  17. Effect of carbon dioxide on the rate of iodine vapor absorption by aqueous solution of sodium hydroxide

    International Nuclear Information System (INIS)

    Eguchi, Wataru; Adachi, Motonari; Miyake, Yoshikazu

    1978-01-01

    There is always carbon dioxide in the atmosphere as an impurity. Since this is an acid gas similar to iodine, each absorption rate seems to be affected by the other due to the coexistence of these two. Experiments have been conducted to clarify the absorption rate and absorption mechanism of iodine in the simultaneous absorption of iodine and carbon dioxide. Carbon dioxide coexisting with gas phases as an impurity decreases the absorption rate of iodine in the removal by washing with water of iodine mixed in the air. The first cause of this is that the diffusion coefficient of iodine in gas phase decreases with the carbon dioxide content in the gas phase. The second cause is that coexistent carbon dioxide is an acid gas, dissociates by dissolving into the absorbing solution, increases hydrogen ion concentration together with the formation of negative ions of bicarbonate and carbonate, and reduces hydroxyl ion concentration as a result. It is more important that existence of iodine has a catalytic effect to the rate of basic catalytic hydrolysis of carbon dioxide simultaneously dissolved in water phase, and accelerates this reaction rate. The mechanism of catalytic effect of iodine for the hydrolysis of carbon dioxide can not be clarified in detail only by this experiment, but the simultaneous absorption rate of iodine and carbon dioxide can be explained satisfactorily. (Wakatsuki, Y

  18. Uptake and release of glucose by the human kidney. Postabsorptive rates and responses to epinephrine.

    Science.gov (United States)

    Stumvoll, M; Chintalapudi, U; Perriello, G; Welle, S; Gutierrez, O; Gerich, J

    1995-11-01

    Despite ample evidence that the kidney can both produce and use appreciable amounts of glucose, the human kidney is generally regarded as playing a minor role in glucose homeostasis. This view is based on measurements of arteriorenal vein glucose concentrations indicating little or no net release of glucose. However, inferences from net balance measurements do not take into consideration the simultaneous release and uptake of glucose by the kidney. Therefore, to assess the contribution of release and uptake of glucose by the human kidney to overall entry and removal of plasma glucose, we used a combination of balance and isotope techniques to measure renal glucose net balance, fractional extraction, uptake and release as well as overall plasma glucose appearance and disposal in 10 normal volunteers under basal postabsorptive conditions and during a 3-h epinephrine infusion. In the basal postabsorptive state, there was small but significant net output of glucose by the kidney (66 +/- 22 mumol.min-1, P = 0.016). However, since renal glucose fractional extraction averaged 2.9 +/- 0.3%, there was considerable renal glucose uptake (2.3 +/- 0.2 mumol.kg-1.min-1) which accounted for 20.2 +/- 1.7% of systemic glucose disposal (11.4 +/- 0.5 mumol.kg-1.min-1). Renal glucose release (3.2 +/- 0.2 mumol.kg-1.min-1) accounted for 27.8 +/- 2.1% of systemic glucose appearance (11.4 +/- 0.5 mumol.kg-1.min-1). Epinephrine infusion, which increased plasma epinephrine to levels observed during hypoglycemia (3722 +/- 453 pmol/liter) increased renal glucose release nearly twofold (5.2 +/- 0.5 vs 2.8 +/- 0.1 mol.kg-1.min-1, P = 0.01) so that at the end of the infusion, renal glucose release accounted for 40.3 +/- 5.5% of systemic glucose appearance and essentially all of the increase in systemic glucose appearance. These observations suggest an important role for the human kidney in glucose homeostasis.

  19. Regional cerebral metabolic rate for glucose and cerebrospinal fluid monoamine metabolites in subacute sclerosing panencephalitis

    International Nuclear Information System (INIS)

    Yanai, Kazuhiko; Miyabayashi, Shigeaki; Iinuma, Kazuie; Tada, Keiya; Fukuda, Hiroshi; Ito, Masatoshi; Matsuzawa, Taiju.

    1987-01-01

    Regional cerebral metabolic rate for glucose (rCMRglu) and cerebrospinal fluid monoamine metabolites were measured in two cases of subacute sclerosing panencephalitis (SSPE) with different clinical courses. A marked decrease in rCMRglu was found in the cortical gray matter of a patient with rapidly developing SSPE (3.6 - 4.2 mg/100 g brain tissue/min). However, the rCMRglu was preserved in the caudate and lenticular nuclei of the patient (7.7 mg/100 g/min). The rCMRglu in a patient with slowly developing SSPE revealed patterns and values similar to those of the control. Cerebrospinal fluid monoamine metabolites ; homovanilic acid and 5-hydroxyindoleacetic acid, were decreased in both rapidly and slowly developing SSPE. These data indicated that rCMRglu correlated better with the neurological and psychological status and that dopaminergic and serotonergic abnormalities have been implicated in pathophysiology of SSPE. (author)

  20. Enhancement of glomerular filtration rate and renal plasma flow by oral glucose load in well controlled insulin-dependent diabetics

    DEFF Research Database (Denmark)

    Sandahl Christiansen, J; Christensen, C K; Hermansen, K

    1986-01-01

    Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured in 27 patients with uncomplicated insulin-dependent diabetes (IDDM) before and after an oral glucose load of 1.1 g glucose/kg body wt. In the 18 patients showing near-normoglycaemia (blood glucose less than or equal to 8...... mmol/l) before the glucose challenge the increase in blood glucose from 4.2 +/- 1.7 to 15.2 +/- 2.3 mmol/l was accompanied by an enhancement of GFR from 128 +/- 15 to 132 +/- 14 ml/min X 1.73 m2 (2p = 0.030) and of RPF from 534 +/- 116 to 562 +/- 105 ml/min X 1.73 m2 (2p = 0.023). By contrast oral...... glucose load to the nine patients with hyperglycaemia (greater than 8 mmol/l) during baseline conditions raising blood glucose from 11.9 +/- 2.0 to 19.6 +/- 1.5 mmol/l was accompanied by a reduction in GFR from 149 +/- 15 to 139 +/- 9 ml/min X 1.73 m2 (2p less than 0.001) while RPF was unchanged...

  1. Helichrysum and grapefruit extracts inhibit carbohydrate digestion and absorption, improving postprandial glucose levels and hyperinsulinemia in rats.

    Science.gov (United States)

    de la Garza, Ana Laura; Etxeberria, Usune; Lostao, María Pilar; San Román, Belén; Barrenetxe, Jaione; Martínez, J Alfredo; Milagro, Fermín I

    2013-12-11

    Several plant extracts rich in flavonoids have been reported to improve hyperglycemia by inhibiting digestive enzyme activities and SGLT1-mediated glucose uptake. In this study, helichrysum ( Helichrysum italicum ) and grapefruit ( Citrus × paradisi ) extracts inhibited in vitro enzyme activities. The helichrysum extract showed higher inhibitory activity of α-glucosidase (IC50 = 0.19 mg/mL) than α-amylase (IC50 = 0.83 mg/mL), whereas the grapefruit extract presented similar α-amylase and α-glucosidase inhibitory activities (IC50 = 0.42 mg/mL and IC50 = 0.41 mg/mL, respectively). Both extracts reduced maltose digestion in noneverted intestinal sacs (57% with helichrysum and 46% with grapefruit). Likewise, both extracts inhibited SGLT1-mediated methylglucoside uptake in Caco-2 cells in the presence of Na(+) (56% of inhibition with helichrysum and 54% with grapefruit). In vivo studies demonstrated that helichrysum decreased blood glucose levels after an oral maltose tolerance test (OMTT), and both extracts reduced postprandial glucose levels after the oral starch tolerance test (OSTT). Finally, both extracts improved hyperinsulinemia (31% with helichrysum and 50% with grapefruit) and HOMA index (47% with helichrysum and 54% with grapefruit) in a dietary model of insulin resistance in rats. In summary, helichrysum and grapefruit extracts improve postprandial glycemic control in rats, possibly by inhibiting α-glucosidase and α-amylase enzyme activities and decreasing SGLT1-mediated glucose uptake.

  2. Positron emission tomography assessment of cerebral glucose metabolic rates in autism spectrum disorder and schizophrenia.

    Science.gov (United States)

    Mitelman, Serge A; Bralet, Marie-Cecile; Mehmet Haznedar, M; Hollander, Eric; Shihabuddin, Lina; Hazlett, Erin A; Buchsbaum, Monte S

    2018-04-01

    Several models have been proposed to account for observed overlaps in clinical features and genetic predisposition between schizophrenia and autism spectrum disorder. This study assessed similarities and differences in topological patterns and vectors of glucose metabolism in both disorders in reference to these models. Co-registered 18 fluorodeoxyglucose PET and MRI scans were obtained in 41 schizophrenia, 25 ASD, and 55 healthy control subjects. AFNI was used to map cortical and subcortical regions of interest. Metabolic rates were compared between three diagnostic groups using univariate and multivariate repeated-measures ANOVA. Compared to controls, metabolic rates in schizophrenia subjects were decreased in the frontal lobe, anterior cingulate, superior temporal gyrus, amygdala and medial thalamic nuclei; rates were increased in the occipital cortex, hippocampus, basal ganglia and lateral thalamic nuclei. In ASD subjects metabolic rates were decreased in the parietal lobe, frontal premotor and eye-fields areas, and amygdala; rates were increased in the posterior cingulate, occipital cortex, hippocampus and basal ganglia. In relation to controls, subjects with ASD and schizophrenia showed opposite changes in metabolic rates in the primary motor and somatosensory cortex, anterior cingulate and hypothalamus; similar changes were found in prefrontal and occipital cortices, inferior parietal lobule, amygdala, hippocampus, and basal ganglia. Schizophrenia and ASD appear to be associated with a similar pattern of metabolic abnormalities in the social brain. Divergent maladaptive trade-offs, as postulated by the diametrical hypothesis of their evolutionary relationship, may involve a more circumscribed set of anterior cingulate, motor and somatosensory regions and the specific cognitive functions they subserve.

  3. Large specific absorption rates in the magnetic hyperthermia properties of metallic iron nanocubes

    Energy Technology Data Exchange (ETDEWEB)

    Mehdaoui, B.; Meffre, A.; Lacroix, L.-M. [Universite de Toulouse, INSA, UPS, LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), 135 avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR 5215, LPCNO, F-31077 Toulouse (France); Carrey, J., E-mail: julian.carrey@insa-toulouse.f [Universite de Toulouse, INSA, UPS, LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), 135 avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR 5215, LPCNO, F-31077 Toulouse (France); Lachaize, S. [Universite de Toulouse, INSA, UPS, LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), 135 avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR 5215, LPCNO, F-31077 Toulouse (France); Gougeon, M. [Institut CARNOT-CIRIMAT-UMR 5085, Batiment 2R1, 118 route de Narbonne, F-31062 Toulouse (France); Respaud, M. [Universite de Toulouse, INSA, UPS, LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), 135 avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR 5215, LPCNO, F-31077 Toulouse (France); Chaudret, B. [Laboratoire de Chimie de Coordination-CNRS, 205 rte de Narbonne, 31077 Toulouse cedex 4 (France)

    2010-10-15

    We report on the magnetic hyperthermia properties of chemically synthesized ferromagnetic 11 and 16 nm Fe(0) nanoparticles of cubic shape displaying the saturation magnetization of bulk iron. The specific absorption rate measured on 16 nm nanocubes is 1690{+-}160 W/g at 300 kHz and 66 mT. This corresponds to specific losses-per-cycle of 5.6 mJ/g, largely exceeding the ones reported in other systems. A way to quantify the degree of optimization of any system with respect to hyperthermia applications is proposed. Applied here, this method shows that our nanoparticles are not fully optimized, probably due to the strong influence of magnetic interactions on their magnetic response. Once protected from oxidation and further optimized, such nano-objects could constitute efficient magnetic cores for biomedical applications requiring very large heating power.

  4. Determination of Lung-to-Blood Absorption Rates for Lead and Bismuth which are Appropriate for Radon Progeny

    International Nuclear Information System (INIS)

    Marsh, J.W.; Birchall, A.

    1999-01-01

    The ICRP Publication 66 Human Respiratory Tract Model (HRTM) treats clearance as a competitive process between absorption into blood and particle transport to the gastrointestinal tract and lymphatics. The ICRP recommends default absorption rates for lead and bismuth in ICRP Publication 71 but states that the values are not appropriate for short-lived radon progeny. This paper describes an evaluation of published data from volunteer experiments to estimate the absorption half-times of lead and bismuth that are appropriate for short-lived radon progeny. The absorption half-time for lead was determined to be 10±2 h, based on 212 Pb lung and blood retention data from several studies. The absorption half-time for bismuth was estimated to be about 13 h, based on 212 Bi urinary excretion data from one experiment and the ICRP biokinetic model for bismuth as a decay product of lead. (author)

  5. Hysteresis losses and specific absorption rate measurements in magnetic nanoparticles for hyperthermia applications.

    Science.gov (United States)

    Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Martino, Luca; Kane, Shashank N; Raghuvanshi, Saroj; Vinai, Franco; Tiberto, Paola

    2017-06-01

    Magnetic hysteresis loops areas and hyperthermia on magnetic nanoparticles have been studied with the aim of providing reliable and reproducible methods of measuring the specific absorption rate (SAR). The SAR of Fe 3 O 4 nanoparticles with two different mean sizes, and Ni 1-x Zn x Fe 2 O 4 ferrites with 0 ≤ x ≤ 0.8 has been measured with three approaches: static hysteresis loops areas, dynamic hysteresis loops areas and hyperthermia of a water solution. For dynamic loops and thermometric measurements, specific experimental setups have been developed, that operate at comparable frequencies (≈ 69kHz and ≈ 100kHz respectively) and rf magnetic field peak values (up to 100mT). The hyperthermia setup has been fully modelled to provide a direct measurement of the SAR of the magnetic nanoparticles by taking into account the heat exchange with the surrounding environment in non-adiabatic conditions and the parasitic heating of the water due to ionic currents. Dynamic hysteresis loops are shown to provide an accurate determination of the SAR except for superparamagnetic samples, where the boundary with a blocked regime could be crossed in dynamic conditions. Static hysteresis loops consistently underestimate the specific absorption rate but can be used to select the most promising samples. A means of reliably measure SAR of magnetic nanoparticles by different approaches for hyperthermia applications is presented and its validity discussed by comparing different methods. This work fits within the general subject of metrological traceability in medicine with a specific focus on magnetic hyperthermia. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editor: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Effect of Fasting Blood Glucose Level on Heart Rate Variability of Healthy Young Adults.

    Directory of Open Access Journals (Sweden)

    Mohamed Faisal Lutfi

    Full Text Available Previous studies reported increased risk of cardiac events in subjects with fasting blood glucose (FBG levels lower than the diagnostic threshold of diabetes mellitus. However, whether increased cardiac events in those with upper normal FBG is secondary to the shift of their cardiac sympathovagal balance towards sympathetic predominance is unknown.To assess the association between FBG levels and cardiac autonomic modulation (CAM in euglycaemic healthy subjects based on heart rate variability (HRV derived indices.The study enrolled 42 healthy young adults. Following sociodemographic and clinical assessment, blood samples were collected to measure FBG levels. Five minutes ECG recordings were performed to all participants to obtain frequency domain HRV measurements, namely the natural logarithm (Ln of total power (LnTP, very low frequency (LnVLF, low frequency (LnLF and high frequency (LnHF, low frequency/ high frequency ratio (LnLF/HF, normalized low frequency (LF Norm and high frequency (HF Norm.FBG levels correlated positively with LnHF (r = 0.33, P = 0.031 and HF Norm (r = 0.35, P = 0.025 and negatively with LF Norm (r = -0.35, P = 0.025 and LnLF/HF (r = -0.33, P = 0.035. LnHF and HF Norm were significantly decreased in subjects with the lower (4.00 (1.34 ms2/Hz and 33.12 (11.94 n.u compared to those with the upper FBG quartile (5.64 (1.63 ms2/Hz and 49.43 (17.73 n.u, P = 0.013 and 0.032 respectively. LF Norm and LnLF/HF were significantly increased in subjects with the lower (66.88 (11.94 n.u and 0.73 (0.53 compared to those with the higher FBG quartile (50.58 (17.83 n.u and 0.03 (0.79, P = 0.032 and 0.038 respectively.The present study is the first to demonstrate that rise of blood glucose concentration, within physiological range, is associated with higher parasympathetic, but lower sympathetic CAM. Further researches are needed to set out the glycemic threshold beyond which further increase in glucose level readjusts sympathovagal balance

  7. Evaluation of salivary glucose, IgA and flow rate in diabetic patients: a case-control study.

    Science.gov (United States)

    Bakianian Vaziri, P; Vahedi, M; Mortazavi, H; Abdollahzadeh, Sh; Hajilooi, M

    2010-01-01

    An association between diabetes mellitus and alterations in the oral cavity has been noted. In this study, we evaluated differences between salivary IgA, glucose and flow rate in diabetic patients compared with healthy controls. Forty patients with type 1 diabetes, 40 patients with type 2 diabetes and 40 healthy controls were selected. Whole unstimulated saliva samples were collected by the standard method and the salivary flow rate was determined. Nephelometric and Pars method were used to measure salivary IgA and salivary glucose concentrations, respectively. Statistical analysis was performed by Chi-square and t test. There were no significant differences in salivary IgA and glucose concentrations between type 1 and type 2 diabetic patients and their matched control subjects (P>0.05). Salivary flow rate was significantly lower in diabetic patients (Pdiabetic patients than the controls. Determination of salivary constituents may be useful in the description and management of oral findings in diabetic patients.

  8. Comparison between experimental and predicted specific absorption rate of functionalized iron oxide nanoparticle suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Yuan [Mechanical, Aerospace and Nuclear Engineering Department Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Tasciuc, Diana-Andra Borca, E-mail: borcad@rpi.edu [Mechanical, Aerospace and Nuclear Engineering Department Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2011-10-15

    Radio-frequency heated magnetic nanoaparticle suspensions have potential applications in cancer hyperthermia. To optimize these systems for hyperthermia applications it is important to be able to predict how their heat generation or specific absorption rate (SAR) is influenced by various factors, including nanoparticle coating or functionalization and aggregation. However, at present it is unclear how well-existing models predict experimental SAR results. Direct comparisons between predicted and measured SAR are scarce, despite an abundance of works reporting on heat generation rate of various magnetic nanoparticles suspensions. The main objective of this paper is to experimentally assess the validity of current models for SAR and extract information on the effects of coating and aggregation on heat generation rate. In this context, AC susceptibility and magnetization of suspensions of uncoated particles, as well as particles with aminosilane and carboxymethyl-dextran functionalizations, were measured. These properties were then used to predict the heat generation rate in alternating magnetic field starting from first principles, which was then compared to measured SAR. It was found that experimental SAR agrees relatively well with predictions (by a factor of two) when using experimental susceptibility values for the SAR calculation. However, for uncoated and amine-functionalized particles poor agreement (more than an order of magnitude difference) was found when the experimental susceptibility was substituted with predictions based on the Debye model. This apparent discrepancy is attributed to dipolar interactions between nanoparticles within aggregates in these samples, which enhances the imaginary part of the susceptibility and, consequently, the SAR values. The results also suggest that the thermal resistance effect of the coating has little influence on the SAR. - Highlights: > Thermal resistance of nanoparticle coating has little impact on heat dissipation

  9. The regulatory system for diabetes mellitus: Modeling rates of glucose infusions and insulin injections

    Science.gov (United States)

    Yang, Jin; Tang, Sanyi; Cheke, Robert A.

    2016-08-01

    Novel mathematical models with open and closed-loop control for type 1 or type 2 diabetes mellitus were developed to improve understanding of the glucose-insulin regulatory system. A hybrid impulsive glucose-insulin model with different frequencies of glucose infusions and insulin injections was analyzed, and the existence and uniqueness of the positive periodic solution for type 1 diabetes, which is globally asymptotically stable, was studied analytically. Moreover, permanence of the system for type 2 diabetes was demonstrated which showed that the glucose concentration level is uniformly bounded above and below. To investigate how to prevent hyperinsulinemia and hyperglycemia being caused by this system, we developed a model involving periodic intakes of glucose with insulin injections applied only when the blood glucose level reached a given critical glucose threshold. In addition, our numerical analysis revealed that the period, the frequency and the dose of glucose infusions and insulin injections are crucial for insulin therapies, and the results provide clinical strategies for insulin-administration practices.

  10. The Coupling of Cerebral Metabolic Rate of Glucose and Cerebral Blood Flow In Vivo

    DEFF Research Database (Denmark)

    Hasselbalch, Steen; Paulson, Olaf Bjarne

    2012-01-01

    The energy supplied to the brain by metabolic substrate is largely utilized for maintaining synaptic transmission. In this regulation cerebral blood flow and glucose consumption is tightly coupled as well in the resting condition as during activation. Quantification of cerebral blood flow...... not used for aerobic metabolism. Although some of the excess glucose uptake can be explained by lactate production, this phenomenon can still not account for the excess glucose uptake. Thus, more complex metabolic patterns in the brain might be reflected in the excess glucose uptake during activation......, and especially temporal relationships must be taken into account. What triggers the flow increase during functional brain activation is not entirely elucidated. The demand for excess glucose uptake may be important and a possible oxygen deficit in tissue distant from the capillaries is probably of minor...

  11. Xylitol vs glucose: Effect on the rate of gastric emptying and motilin, insulin, and gastric inhibitory polypeptide release

    International Nuclear Information System (INIS)

    Salminen, E.K.; Salminen, S.J.; Porkka, L.; Kwasowski, P.; Marks, V.; Koivistoinen, P.E.

    1989-01-01

    The effect of xylitol and glucose on the rate of gastric emptying and intestinal transit and on motilin, gastric inhibitory polypeptide (GIP), and insulin release were studied in human volunteers. A single oral dose of 200 mL water containing 30 g glucose or 30 g xylitol, mixed with a 99m technetium-tin (99mTc-Sn) colloid, was used. Similar dosing without the label was used in motilin, GIP, and insulin studies. Xylitol decreased the rate of gastric emptying but concomitantly accelerated intestinal transit compared with glucose. The half-times for gastric emptying were 77.5 +/- 4.6 and 39.8 +/- 3.4 min after ingestion of xylitol and glucose solutions, respectively. Glucose suppressed motilin and stimulated GIP secretion; xylitol stimulated motilin secretion but had no effect on GIP, which is currently the main candidate for the role of enterogastrone. The accelerated intestinal transit and increase in plasma motilin observed after xylitol ingestion were thought to be causally related to the diarrhea and gastrointestinal discomfort produced by it

  12. Reaction rate studies of glucose-6-phosphate dehydrogenase activity in sections of rat liver using four tetrazolium salts

    NARCIS (Netherlands)

    Butcher, R. G.; van Noorden, C. J.

    1985-01-01

    The reaction rate of glucose-6-phosphate dehydrogenase activity in liver sections from fed and starved rats has been monitored by the continuous measurement at 37 degrees C of the reaction product as it is formed using scanning and integrating microdensitometry. Control media lacked either substrate

  13. Development of a kinetic model of hydrogen absorption and desorption in magnesium and analysis of the rate-determining step

    Science.gov (United States)

    Kitagawa, Yuta; Tanabe, Katsuaki

    2018-05-01

    Mg is promising as a new light-weight and low-cost hydrogen-storage material. We construct a numerical model to represent the hydrogen dynamics on Mg, comprising dissociative adsorption, desorption, bulk diffusion, and chemical reaction. Our calculation shows a good agreement with experimental data for hydrogen absorption and desorption on Mg. Our model clarifies the evolution of the rate-determining processes as absorption and desorption proceed. Furthermore, we investigate the optimal condition and materials design for efficient hydrogen storage in Mg. By properly understanding the rate-determining processes using our model, one can determine the design principle for high-performance hydrogen-storage systems.

  14. Effects on the glucose metabolism in type II diabetes model mice treated with dose-rates irradiation

    International Nuclear Information System (INIS)

    Nomura, Takaharu; Sakai, Kazuo

    2004-01-01

    The effects of low-dose rate gamma-irradiation on the type II diabetes mellitus were investigated in C57BL/KsJ-ab/db (db mouse). This mouse develops the type II diabetes within 8 weeks of the birth due to a dysfunction of the insulin receptors. As a result the db mouse shows obese and exhibits hyperinsulinism. Ten-week old female mice (12 mice in each group) were irradiated with gamma-rays at 0.35 mGy/hr, 0.65 mGy/hr or 1.2 mGy/hr in the low-dose rate irradiation facility in the Low Dose Radiation Research Center. The level of plasma glucose and insulin was measured. After 2 weeks irradiation, the glucose level slightly increased, however the difference between the irradiated mice and non-irradiated groups was not significant. The plasma insulin concentration decreased in the non-irradiated group to half of the initial level. In the irradiated group, it also decreased but in the group of 0.65 mGy/hr and 0.35 mGy/hr, it was significantly differed from that in the non-irradiated group. In the glucose tolerance test, plasma glucose level increased shortly after 0.1 mg/head glucose injection by mouth and reached to a peak at 90-120 min after the injection. The glucose level of the non-irradiated mice was slightly higher than that of irradiated mice. The plasma insulin level of non-irradiated group was enhanced after the injection and maintained the level during the test. However the levels of irradiated mice were decreased at 30-60 min after the injection. Both the level of non-irradiated an irradiated was almost same but the non-irradiated one was a little high. In all of mice, the plasma insulin level was highly elevated right after the 0.05 units/head insulin injection by i.p. and the levels were also gradually decreased. The level of the non-irradiated group was slowly decreased and was higher than the irradiated mice. The plasma glucose levels of all mice did not change after the test; however, the levels of irradiated mice were slightly lower than that of non

  15. Assessment of specific energy absorption rate (SAR) in the head from a TETRA handset

    International Nuclear Information System (INIS)

    Dimbylow, Peter; Khalid, Mohammed; Mann, Simon

    2003-01-01

    Finite-difference time-domain (FDTD) calculations of the specific energy absorption rate (SAR) from a representative TETRA handset have been performed in an anatomically realistic model of the head. TETRA (Terrestrial Trunked Radio) is a modern digital private mobile radio system designed to meet the requirements of professional users, such as the police and fire brigade. The current frequency allocations in the UK are 380-385 MHz and 390-395 MHz for the public sector network. A comprehensive set of calculations of SAR in the head was performed for positions of the handset in front of the face and at both sides of the head. The representative TETRA handset considered, operating at 1 W in normal use, will show compliance with both the ICNIRP occupational and public exposure restrictions. The handset with a monopole antenna operating at 3 W in normal use will show compliance with both the ICNIRP occupational and public exposure restrictions. The handset with a helical antenna operating at 3 W in normal use will show compliance with the ICNIRP occupational exposure restriction but will be over the public exposure restriction by up to ∼50% if kept in the position of maximum SAR for 6 min continuously

  16. Cerebral metabolic rates for glucose in mood disorders. Studies with positron emission tomography and fluorodeoxyglucose F 18

    International Nuclear Information System (INIS)

    Baxter, L.R. Jr.; Phelps, M.E.; Mazziotta, J.C.; Schwartz, J.M.; Gerner, R.H.; Selin, C.E.; Sumida, R.M.

    1985-01-01

    Cerebral metabolic rates for glucose were examined in patients with unipolar depression (N = 11), bipolar depression (N = 5), mania (N = 5), bipolar mixed states (N = 3), and in normal controls (N = 9) using positron emission tomography and fluorodeoxyglucose F 18. All subjects were studied supine under ambient room conditions with eyes open. Bipolar depressed and mixed patients had supratentorial whole brain glucose metabolic rates that were significantly lower than those of the other comparison groups. The whole brain metabolic rates for patients with bipolar depression increased going from depression or a mixed state to a euthymic or manic state. Patients with unipolar depression showed a significantly lower ratio of the metabolic rate of the caudate nucleus, divided by that of the hemisphere as a whole, when compared with normal controls and patients with bipolar depression

  17. Functional imaging and assessment of the glucose diffusion rate in epithelial tissues in optical coherence tomography

    International Nuclear Information System (INIS)

    Larin, K V; Tuchin, V V

    2008-01-01

    Functional imaging, monitoring and quantitative description of glucose diffusion in epithelial and underlying stromal tissues in vivo and controlling of the optical properties of tissues are extremely important for many biomedical applications including the development of noninvasive or minimally invasive glucose sensors as well as for therapy and diagnostics of various diseases, such as cancer, diabetic retinopathy, and glaucoma. Recent progress in the development of a noninvasive molecular diffusion biosensor based on optical coherence tomography (OCT) is described. The diffusion of glucose was studied in several epithelial tissues both in vitro and in vivo. Because OCT provides depth-resolved imaging of tissues with high in-depth resolution, the glucose diffusion is described not only as a function of time but also as a function of depth. (special issue devoted to application of laser technologies in biophotonics and biomedical studies)

  18. Evaluation of Salivary Glucose, IgA and Flow Rate in Diabetic Patients: A Case-Control Study

    OpenAIRE

    Bakianian Vaziri, P.; Vahedi, M.; Mortazavi, H.; Abdollahzadeh, Sh.; Hajilooi, M.

    2010-01-01

    Objective: An association between diabetes mellitus and alterations in the oral cavity has been noted. In this study, we evaluated differences between salivary IgA, glucose and flow rate in diabetic patients compared with healthy controls. Materials and Methods: Forty patients with type 1 diabetes, 40 patients with type 2 diabetes and 40 healthy controls were selected. Whole unstimulated saliva samples were collected by the standard method and the salivary flow rate was determined. Nephelomet...

  19. High-Temperature Gas-Cooled Reactor Critical Experiment and its Application to Thorium Absorption Rates

    International Nuclear Information System (INIS)

    Bardes, R.G.; Brown, J.R.; Drake, M.K.; Fischer, P.U.; Pound, D.C.; Sampson, J.B.; Stewart, H.B.

    1964-01-01

    In developing the concept of the HTGR and its first prototype at Peach Bottom, General Atomic made the decision that a critical experiment was required to provide adequately certain necessary input data for the nuclear analysis. The specific needs of the nuclear design theory for input data relating to thorium absorptions led to an experimental design consisting of a central lattice-type critical assembly with surrounding buffer and driver regions. This type of assembly, in which the spectrum of interest can be established in the relatively small central lattice having a desired geometry, provides a useful tool for obtaining a variety of input data for nuclear analysis surveys of new concepts. The particular advantages of this approach over that of constructing a mock-up assembly will be discussed, as well as the role of the theory in determining what experiments are most useful and how these experiments are then used in verifying design techniques. Two relatively new techniques were developed for use in the lattice assembly. These were a reactivity oscillation technique for determining the thorium Doppler coefficient, and an activation technique for determining both the resonance integral of thorium dispersed in graphite and its temperature dependence (activation Doppler coefficient). The Doppler coefficient measurement by reactivity oscillation utilized the entire central fuel element in a technique which permitted heating this fuel element to 800°F and accurately subtracting experimentally the thermal-base effects, that is, those effects not contributing to the thorium resonance capture. Comparison of results with theory for a range of conditions shows excellent agreement. The measurement of the thorium resonance integral and its temperature dependence will be described. The technique developed for measuring resonance capture makes use of gold as the standard and vanadium as die material giving the 1/v absorption rate. This technique is dictated by the fact

  20. Increasing synthetic serum substitute (SSS) concentrations in P1 glucose/phosphate-free medium improves implantation rate: a comparative study.

    Science.gov (United States)

    Ben-Yosef, D; Yovel, I; Schwartz, T; Azem, F; Lessing, J B; Amit, A

    2001-11-01

    To assess the comparative efficacy of IVF medium (MediCult, with 5.2 mM glucose) and a glucose/phosphate-free medium, P1 (Irvine Scientific), and to investigate the influence of increasing the serum supplementation (synthetic serum substitute; SSS; Irvine Scientific) to P1 on embryo development and implantation. Patients were randomly assigned to IVF medium (Group 1, cycles n = 172) or P1 supplemented with 10% SSS (Group 2, cycles n = 229) according to the medium scheduled for use on the day of oocyte retrieval. Another 555 IVF consequent cycles (Group 3) were performed using increased SSS concentrations (20%) in P1 medium. In this large series of IVF cycles, we herein demonstrate that significantly higher pregnancy and implantation rates were found when embryos were cultured in glucose/phosphate-free medium P1 supplemented with 20% SSS compared to supplementation with the lower SSS concentration and with IVF medium.

  1. The effect of sewage sludge application on the growth and absorption rates of Pb and As in water spinach

    Directory of Open Access Journals (Sweden)

    Rong Wang

    2016-01-01

    Full Text Available This paper investigated the effect of the application of sewage sludge on the growth rates and absorption rates of Pb and As in potted water spinach. Our results indicated that application of sewage sludge promoted vegetable growth, and the dry weight of water spinach reached a maximal value (4.38 ± 0.82 g upon 8% sludge application. We also found that the dry weights of water spinach after treatment were all greater than those of the control systems (CK. Treatment with sludge promoted the absorption of Pb and As in water spinach, with a significant (p < 0.05 increase of absorbed Pb following treatment concentrations above 10%, and a peak absorption of As at 8%. Finally, we found that concentrations of Pb and As were higher in rhizosphere-attached soil than in free pot.

  2. Effect of endorsed body weight on specific absorption rate during magnetic resonance imaging

    International Nuclear Information System (INIS)

    Singh, Harish K.; Gupta, R.K.; Gujral, R.B.; Shukla, A.K.

    2001-01-01

    As a routine safety of the patients undergoing magnetic resonance imaging (MRI), the limits of radiofrequency (RF) specific absorption rate (SAR) are set by the manufacturers of all MRI systems because RF causes thermo genesis of the RF exposed tissue. It has been mandatory practice to endorse body weight and age of the patients required by the MRI systems for the SAR check. The problems arise on those patients who are critically ill, and consequently body weight could not be measured. In such cases, approximate body weight has to be endorsed. In case of underweight and overweight patients, sometimes SAR check does not permit to run the MRI pulse sequences. Also, in such cases, body weight remains the parameter which is being changed to get the MRI done. The purpose of this study is to assess the change of SAR with endorsed body weight. The change of SAR was recorded with the endorsed weight using phantoms and most commonly used T1 and T2 weighted pulse sequence on clinical MRI system. At true endorsed weight, using respective coils and the head and spine coil phantoms, the body averaged and localised SAR were found to be within limits while this was not the case with body coil phantom. Unrealistic endorsed weights are permissible for the adult age cases in all coils while using the routine T1 and T2 weighted pulse sequences. This finding is absolutely new in the field and certainly, will be of great applicability to develop a uniform and standard system of SAR checks in the patient interest. (author)

  3. Changes in ruminal volatile fatty acid production and absorption rate during the dry period and early lactation as affected by rate of increase of concentrate allowance

    NARCIS (Netherlands)

    Dieho, K.; Dijkstra, J.; Schonewille, J. T.; Bannink, A.

    The aim of the present experiment was to study changes in volatile fatty acid (VFA) production using an isotope dilution technique, and changes in VFA fractional absorption rate (k aVFA) using a buffer incubation technique (BIT) during the dry period and early lactation, as affected by the

  4. Enzymatic conversion of sucrose to glucose and its anomerization by quantitative NMR spectroscopy: Application of a simple consecutive reaction rates approach

    Science.gov (United States)

    Singh, Jaideep; Her, Cheenou; Krishnan, V. V.

    2018-02-01

    The anomerization of carbohydrates is an essential process that determines the relative stabilization of stereoisomers in an aqueous solution. In a typical real-time enzyme kinetics experiment, the substrate (sucrose) is converted to glucose and fructose by the enzyme invertase. The product (α-D-glucose) starts to convert to β-D-glucose immediately by hydrolysis. Though the anomerization process is independent of the enzyme catalysis, the progress curve describing the production of β-D-glucose from α-D-glucose is directly affected by the kinetics of consecutive reactions. When α-D-glucose is continually converted to β-D-glucose, by the enzymatic action, the time course of both α- and β-D-glucose is influenced by the enzyme kinetics. Thus, a reversible first-order rate equation is not adequate to model the reaction mechanism, leading to erroneous results on the rates of formation of the glucose anomers. In this manuscript, we incorporate an approximate method to address consecutive general reactions involving enzyme kinetics and first-order reaction processes. The utility of the approach is demonstrated in the real-time NMR measurement of the anomerization process of α-D-glucose (enzymatically produced from sucrose) to β-D-glucose, as a function of invertase enzyme concentration. Variable temperature experiments were used to estimate the thermodynamic parameters of the anomerization process and are consistent with literature values.

  5. Glucose patterns during an oral glucose tolerance test and associations with future diabetes, cardiovascular disease and all-cause mortality rate

    DEFF Research Database (Denmark)

    Hulman, Adam; Vistisen, Dorte; Glümer, Charlotte

    2018-01-01

    classes. Results: Four distinct glucose patterns during the OGTT were identified. One pattern was characterised by high 30 min but low 2 h glucose values. Participants with this pattern had an increased risk of developing diabetes compared with participants with lower 30 min and 2 h glucose levels (HR 4...

  6. Effect of Feed Gas Flow Rate on CO2 Absorption through Super Hydrophobic Hollow Fiber membrane Contactor

    Science.gov (United States)

    Kartohardjono, Sutrasno; Alexander, Kevin; Larasati, Annisa; Sihombing, Ivander Christian

    2018-03-01

    Carbon dioxide is pollutant in natural gas that could reduce the heating value of the natural gas and cause problem in transportation due to corrosive to the pipeline. This study aims to evaluate the effects of feed gas flow rate on CO2 absorption through super hydrophobic hollow fiber contactor. Polyethyleneglycol-300 (PEG-300) solution was used as absorbent in this study, whilst the feed gas used in the experiment was a mixture of 30% CO2 and 70% CH4. There are three super hydrophobic hollow fiber contactors sized 6 cm and 25 cm in diameter and length used in this study, which consists of 1000, 3000 and 5000 fibers, respectively. The super hydrophobic fiber membrane used is polypropylene-based with outer and inner diameter of about 525 and 235 μm, respectively. In the experiments, the feed gas was sent through the shell side of the membrane contactor, whilst the absorbent solution was pumped through the lumen fibers. The experimental results showed that the mass transfer coefficient, flux, absorption efficiency for CO2-N2 system and CO2 loading increased with the feed gas flow rate, but the absorption efficiency for CO2-N2 system decreased. The mass transfer coefficient and the flux, at the same feed gas flow rate, decreased with the number of fibers in the membrane contactor, but the CO2 absorption efficiency and the CO2 loading increased.

  7. High-content screening of Aspergillus niger with both increased production and high secretion rate of glucose oxidase.

    Science.gov (United States)

    Zhu, Xudong; Sun, Jingchun; Chu, Ju

    2018-01-01

    To develop a rapid, dual-parameter, plate-based screening process to improve production and secretion rate of glucose oxidase simultaneously in Aspergillus niger. A morphology engineering based on CaCO 3 was implemented, where the yield of GOD by A. niger was increased by up to 50%. Analysis of extracellular GOD activity was achieved in 96-well plates. There was a close negative correlation between the total GOD activity and its residual glucose of the fermentation broth. Based on this, a rapid, plate-based, qualitative analysis method of the total GOD activity was developed. Compared with the conventional analysis method using o-dianisidine, a correlation coefficient of -0.92 by statistical analysis was obtained. Using this dual-parameter screening method, we acquired a strain with GOD activity of 3126 U l -1 , which was 146% higher than the original strain. Its secretion rate of GOD was 83, 32% higher than the original strain.

  8. A low perfusion rate microreactor for the continous monitoring of enzyme characteristics: applications for glucose oxidase.

    NARCIS (Netherlands)

    Posthuma-Trumpie, G.A.; Venema, K.; Berkel, van W.J.H.; Korf, J.

    2007-01-01

    This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver

  9. A low perfusion rate microreactor for continuous monitoring of enzyme characteristics : application to glucose oxidase

    NARCIS (Netherlands)

    Posthuma-Trumpie, G. A.; Venema, K.; van Berkel, W. J. H.; Korf, J.

    This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver

  10. Fast evolutionary rates associated with functional loss in class I glucose transporters of Schistosoma mansoni

    Czech Academy of Sciences Publication Activity Database

    Cabezas-Cruz, A.; Valdés, James J.; Lancelot, J.; Pierce, R.J.

    2015-01-01

    Roč. 16, NOV 19 2015 (2015), s. 980 ISSN 1471-2164 R&D Projects: GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 Keywords : Schistosoma mansoni * glucose transporters * transcriptional regulation * phylogen * biophysics Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.867, year: 2015

  11. Importance of collisional rates for anomalous absorption in H2CO molecule

    International Nuclear Information System (INIS)

    Sharma, Monika; Sharma, M.K.; Chandra, Suresh

    2012-01-01

    Formaldehyde (H 2 CO) is the first organic molecule identified in a number of galactic and extragalactic radio sources through its transition 1 10 –1 11 at 4.830 GHz in absorption. Later on, this transition was found in anomalous absorption. In some cosmic objects, this transition however was found in emission and even as a maser radiation. Since the transition 1 10 –1 11 of ortho-H 2 CO is considered as a unique probe of high density gas at low temperature, the study of H 2 CO has always been of great importance for astrophysicists as well as for spectroscopists. In view of the availability of better input data required for such investigation, it is worth while to investigate again about the radiations from ortho-H 2 CO. In the present study, we have investigated anomalous absorption of 1 10 –1 11 , 2 11 –2 12 and 3 12 –3 13 transitions of ortho-H 2 CO. The present results are more reliable as compared to those obtained earlier. -- Highlights: ► Accurate rotational levels and A-coefficients for H 2 CO are calculated. ► Transitions 1 10 –1 11 , 2 11 –2 12 and 3 12 –3 13 show anomalous absorption. ► Anomalous absorption is found to increase with kinetic temperature. ► Anomalous absorption may be found for n H 2 ≈10 4 cm −3 . ► Colliding partner para-H 2 may be approximated as He atom.

  12. Evaluation of Salivary Glucose, IgA and Flow Rate in Diabetic Patients: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    P. Bakianian Vaziri

    2010-03-01

    Full Text Available Objective: An association between diabetes mellitus and alterations in the oral cavity has been noted. In this study, we evaluated differences between salivary IgA, glucose and flow rate in diabetic patients compared with healthy controls.Materials and Methods: Forty patients with type 1 diabetes, 40 patients with type 2 diabetes and 40 healthy controls were selected. Whole unstimulated saliva samples were collected by the standard method and the salivary flow rate was determined. Nephelometricand Pars method were used to measure salivary IgA and salivary glucose concentrations,respectively. Statistical analysis was performed by Chi-square and t test.Results: There were no significant differences in salivary IgA and glucose concentrations between type 1 and type 2 diabetic patients and their matched control subjects (P>0.05.Salivary flow rate was significantly lower in diabetic patients (P<0.05. In addition,DMFT was higher in diabetic patients than the controls.Conclusion: Determination of salivary constituents may be useful in the description and management of oral findings in diabetic patients.

  13. Combined Acquisition Technique (CAT) for Neuroimaging of Multiple Sclerosis at Low Specific Absorption Rates (SAR)

    Science.gov (United States)

    Biller, Armin; Choli, Morwan; Blaimer, Martin; Breuer, Felix A.; Jakob, Peter M.; Bartsch, Andreas J.

    2014-01-01

    Purpose To compare a novel combined acquisition technique (CAT) of turbo-spin-echo (TSE) and echo-planar-imaging (EPI) with conventional TSE. CAT reduces the electromagnetic energy load transmitted for spin excitation. This radiofrequency (RF) burden is limited by the specific absorption rate (SAR) for patient safety. SAR limits restrict high-field MRI applications, in particular. Material and Methods The study was approved by the local Medical Ethics Committee. Written informed consent was obtained from all participants. T2- and PD-weighted brain images of n = 40 Multiple Sclerosis (MS) patients were acquired by CAT and TSE at 3 Tesla. Lesions were recorded by two blinded, board-certificated neuroradiologists. Diagnostic equivalence of CAT and TSE to detect MS lesions was evaluated along with their SAR, sound pressure level (SPL) and sensations of acoustic noise, heating, vibration and peripheral nerve stimulation. Results Every MS lesion revealed on TSE was detected by CAT according to both raters (Cohen’s kappa of within-rater/across-CAT/TSE lesion detection κCAT = 1.00, at an inter-rater lesion detection agreement of κLES = 0.82). CAT reduced the SAR burden significantly compared to TSE (pCAT were 29.0 (±5.7) % for the T2-contrast and 32.7 (±21.9) % for the PD-contrast (expressed as percentages of the effective SAR limit of 3.2 W/kg for head examinations). Average SPL of CAT was no louder than during TSE. Sensations of CAT- vs. TSE-induced heating, noise and scanning vibrations did not differ. Conclusion T2−/PD-CAT is diagnostically equivalent to TSE for MS lesion detection yet substantially reduces the RF exposure. Such SAR reduction facilitates high-field MRI applications at 3 Tesla or above and corresponding protocol standardizations but CAT can also be used to scan faster, at higher resolution or with more slices. According to our data, CAT is no more uncomfortable than TSE scanning. PMID:24608106

  14. Combined acquisition technique (CAT for neuroimaging of multiple sclerosis at low specific absorption rates (SAR.

    Directory of Open Access Journals (Sweden)

    Armin Biller

    Full Text Available PURPOSE: To compare a novel combined acquisition technique (CAT of turbo-spin-echo (TSE and echo-planar-imaging (EPI with conventional TSE. CAT reduces the electromagnetic energy load transmitted for spin excitation. This radiofrequency (RF burden is limited by the specific absorption rate (SAR for patient safety. SAR limits restrict high-field MRI applications, in particular. MATERIAL AND METHODS: The study was approved by the local Medical Ethics Committee. Written informed consent was obtained from all participants. T2- and PD-weighted brain images of n = 40 Multiple Sclerosis (MS patients were acquired by CAT and TSE at 3 Tesla. Lesions were recorded by two blinded, board-certificated neuroradiologists. Diagnostic equivalence of CAT and TSE to detect MS lesions was evaluated along with their SAR, sound pressure level (SPL and sensations of acoustic noise, heating, vibration and peripheral nerve stimulation. RESULTS: Every MS lesion revealed on TSE was detected by CAT according to both raters (Cohen's kappa of within-rater/across-CAT/TSE lesion detection κCAT = 1.00, at an inter-rater lesion detection agreement of κLES = 0.82. CAT reduced the SAR burden significantly compared to TSE (p<0.001. Mean SAR differences between TSE and CAT were 29.0 (± 5.7 % for the T2-contrast and 32.7 (± 21.9 % for the PD-contrast (expressed as percentages of the effective SAR limit of 3.2 W/kg for head examinations. Average SPL of CAT was no louder than during TSE. Sensations of CAT- vs. TSE-induced heating, noise and scanning vibrations did not differ. CONCLUSION: T2-/PD-CAT is diagnostically equivalent to TSE for MS lesion detection yet substantially reduces the RF exposure. Such SAR reduction facilitates high-field MRI applications at 3 Tesla or above and corresponding protocol standardizations but CAT can also be used to scan faster, at higher resolution or with more slices. According to our data, CAT is no more uncomfortable than TSE scanning.

  15. Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head.

    Science.gov (United States)

    Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Rasouli Amirhajeloo, Leila; Mirzaei, Maryam

    2016-09-01

    The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m  and 2.23±0.39 v/m , respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23 %and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart  mobile phones at the frequencies of 900 and 1800 MHz  was significantly higher than Samsung (p value Samsung smart mobile phone.

  16. The absorption of lactic acid is more synchronized with the absorption of glucose than with the absorption of short-chain fatty acids - A study with sows fed diets varying in dietary fibre

    DEFF Research Database (Denmark)

    Serena, Anja; Bach Knudsen, Knud Erik; Jørgensen, Henry

    2007-01-01

    Sows were fed one of three diets varying in level and type of dietary fibre (DF). A low DF diet (LF; 17% DF) based on wheat and barley and two generic high DF diets (HF1, high in soluble DF and HF2, high in insoluble DF; approx. 41% DF) where the cereals were substituted with co-products (sugar....../d of the three experimental diets in a repeated 3 × 3 crossover design. Blood samples were collected the last day in each period at - 120, - 60, 0, 15, 30, 45, 60, 90, 120 and then at 60-min intervals up to 600 min after feeding. Although lactic acid (LA) is formed by microbial fermentation, the absorption...

  17. Skin dose rate conversion factors after contamination with radiopharmaceuticals: influence of contamination area, epidermal thickness and percutaneous absorption

    International Nuclear Information System (INIS)

    Covens, P; Berus, D; Caveliers, V; Struelens, L; Vanhavere, F; Verellen, D

    2013-01-01

    Skin contamination with radiopharmaceuticals can occur during biomedical research and daily nuclear medicine practice as a result of accidental spills, after contact with bodily fluids of patients or by inattentively touching contaminated materials. Skin dose assessment should be carried out by repeated quantification to map the course of the contamination together with the use of appropriate skin dose rate conversion factors. Contamination is generally characterised by local spots on the palmar surface of the hand and complete decontamination is difficult as a result of percutaneous absorption. This specific issue requires special consideration as to the skin dose rate conversion factors as a measure for the absorbed dose rate to the basal layer of the epidermis. In this work we used Monte Carlo simulations to study the influence of the contamination area, the epidermal thickness and the percutaneous absorption on the absorbed skin dose rate conversion factors for a set of 39 medical radionuclides. The results show that the absorbed dose to the basal layer of the epidermis can differ by up to two orders of magnitude from the operational quantity H p (0.07) when using an appropriate epidermal thickness in combination with the effect of percutaneous absorption. (paper)

  18. Simultaneous measurement of glucose blood–brain transport constants and metabolic rate in rat brain using in-vivo 1H MRS

    Science.gov (United States)

    Du, Fei; Zhang, Yi; Zhu, Xiao-Hong; Chen, Wei

    2012-01-01

    Cerebral glucose consumption and glucose transport across the blood–brain barrier are crucial to brain function since glucose is the major energy fuel for supporting intense electrophysiological activity associated with neuronal firing and signaling. Therefore, the development of noninvasive methods to measure the cerebral metabolic rate of glucose (CMRglc) and glucose transport constants (KT: half-saturation constant; Tmax: maximum transport rate) are of importance for understanding glucose transport mechanism and neuroenergetics under various physiological and pathological conditions. In this study, a novel approach able to simultaneously measure CMRglc, KT, and Tmax via monitoring the dynamic glucose concentration changes in the brain tissue using in-vivo 1H magnetic resonance spectroscopy (MRS) and in plasma after a brief glucose infusion was proposed and tested using an animal model. The values of CMRglc, Tmax, and KT were determined to be 0.44±0.17 μmol/g per minute, 1.35±0.47 μmol/g per minute, and 13.4±6.8 mmol/L in the rat brain anesthetized with 2% isoflurane. The Monte-Carlo simulations suggest that the measurements of CMRglc and Tmax are more reliable than that of KT. The overall results indicate that the new approach is robust and reliable for in-vivo measurements of both brain glucose metabolic rate and transport constants, and has potential for human application. PMID:22714049

  19. Effect of NMDA Receptor Antagonist on Local Cerebral Glucose Metabolic Rate in Focal Cerebral Ischemia

    International Nuclear Information System (INIS)

    Kim, Sang Eun; Hong, Seung Bong; Yoon, Byung Woo

    1995-01-01

    There has recently been increasing interest in the use of NMDA receptor antagonists as potential neuroprotective agents for the treatment of ischemic stroke. To evaluate the neuroprotective effect of the selective non-competitive NMDA receptor antagonist MK-801 in focal cerebral ischemia, local cerebral glucose utilization (1CGU) was examined in 15 neuroanatomically discrete regions of the conscious rat brain using the 2-deoxy-D[14C]glucose quantitative autoradiographic technique 24 hr after left middle cerebral artery occlusion (MCAO). Animals received MK-801 (5 mg/kg i.v.) or saline vehicle before (20-30 min) or after (30 min) MCAO. Both pretreatment and posttreatment of MK-801 increased occluded/non-occluded 1CGU ratio in 7 and 5 of the 15 regions measured, respectively(most notably in cortical structures). Following MK-801 pretreatment, there was evidence of widespread increases in 1CCPU not only in the non-occluded hemisphere (12 of the 15 areas studied) but also in the occluded hemisphere (13 of the 15 areas studied), while MK-801 posttreatment did not significantly increase 1CGU both in the normal and occluded hemispheres. These data indicate that MK-801 has a neuroprotective effect in focal cerebral ischemia and demonstrate that MK-801 provides widespread alterations of glucose utilization in conscious animals.

  20. Rates of myocardial infarction and stroke in patients initiated on SGLT2-inhibitors versus other glucose-lowering agents in real-world clinical practice

    DEFF Research Database (Denmark)

    Kosiborod, Mikhail; Birkeland, Kåre I; Cavender, Matthew A

    2018-01-01

    The multinational, observational CVD-REAL study recently showed that initiation of sodium-glucose co-transporter-2 inhibitors (SGLT-2i) was associated with significantly lower rates of death and heart failure vs. other glucose-lowering drugs (oGLDs). This sub-analysis of CVD-REAL sought to determ...

  1. Riluzole increases the rate of glucose transport in L6 myotubes and NSC-34 motor neuron-like cells via AMPK pathway activation.

    Science.gov (United States)

    Daniel, Bareket; Green, Omer; Viskind, Olga; Gruzman, Arie

    2013-09-01

    Riluzole is the only approved ALS drug. Riluzole influences several cellular pathways, but its exact mechanism of action remains unclear. Our goal was to study the drug's influence on the glucose transport rate in two ALS relevant cell types, neurons and myotubes. Stably transfected wild-type or mutant G93A human SOD1 NSC-34 motor neuron-like cells and rat L6 myotubes were exposed to riluzole. The rate of glucose uptake, translocation of glucose transporters to the cell's plasma membrane and the main glucose transport regulatory proteins' phosphorylation levels were measured. We found that riluzole increases the glucose transport rate and up-regulates the translocation of glucose transporters to plasma membrane in both types of cells. Riluzole leads to AMPK phosphorylation and to the phosphorylation of its downstream target, AS-160. In conclusion, increasing the glucose transport rate in ALS affected cells might be one of the mechanisms of riluzole's therapeutic effect. These findings can be used to rationally design and synthesize novel anti-ALS drugs that modulate glucose transport in neurons and skeletal muscles.

  2. Effect of adrenaline and alpha-agonists on net rate of liquid absorption from the pleural space of rabbits.

    Science.gov (United States)

    Zocchi, L; Raffaini, A; Agostoni, E

    1997-05-01

    Indirect evidence supporting a solute-coupled liquid absorption from the pleural space of rabbits has recently been provided; moreover, the beta 2-adrenoceptor agonist terbutaline has been found to increase this absorption. In this study the effect of adrenaline and alpha-adrenoceptor agonists on net rate of liquid absorption (Jnet) from albumin Ringer hydrothoraces of various sizes has been determined in anaesthetized rabbits. In hydrothoraces with adrenaline (5 x 10(-6) M) the relationship between Jnet and volume of liquid injected was displaced upwards by 0.09 ml h-1 relative to that in control hydrothoraces (P liquid absorption, since beta-agonists inhibit lymphatic activity while, at relatively high concentrations, they may increase active transport. Conversely, the strong stimulation of lymphatic alpha-receptors that should occur with adrenaline after beta-blockade may fail to increase lymphatic drainage, because it has been shown that the increase in contraction frequency of lymphatics may be balanced by the decrease in their stroke volume. Arterial blood pressure during the hydrothoraces with adrenaline was unchanged. In hydrothoraces with the alpha 2-agonist clonidine (5 x 10(-6) M; a less potent agent than adrenaline) the slope of the relationship between Jnet and volume injected increased by 26% (P liquid load. In hydrothoraces with the alpha 1-agonist phenylephrine (5 x 10(-6) or 10(-7) M) Jnet was simlar to control values.

  3. Glucose pump test can be used to measure blood flow rate of native arteriovenous fistula in chronic hemodialysis.

    Science.gov (United States)

    Yavuz, Y C; Selcuk, N Y; Altıntepe, L; Güney, I; Yavuz, S

    2018-01-01

    In chronic hemodialysis patients, the low flow of vascular access may leads to inadequate dialysis, increased rate of hospitalization, morbidity, and mortality. It was found that surveillance should be performed for native arteriovenous (AV) should not be performed for AV graft in various studies. However, surveillance was done in graft AV fistulas in most studies. Doppler ultrasonography (US) was suggested for surveillance of AV fistulas by the last vascular access guideline of National Kidney Foundation Disease Outcomes Quality Initiative (NKF KDOQI). The aim of study is to determine whether glucose pump test (GPT) is used for surveillance of native AV fistulas by using Doppler US as reference. In 93 chronic hemodialysis patients with native AV fistula, blood flow rates were measured by Doppler US and GPT. For GPT, glucose was infused to 16 mL/min by pump and was measured at basal before the infusion and 11 s after the start of the infusion by glucometer. Doppler US was done by an expert radiologist. Used statistical tests were Mann-Whitney U test, Friedman test, regression analysis, and multiple regression analysis. Median values of blood flow rates measured by GPT (707 mL/min) and by Doppler US (700 mL/min) were not different (Z = 0.414, P = 0.678). Results of GPT and Doppler US measurements were positive correlate by regression analysis. The mean GPT value of diabetic patients (n = 39; 908 mL/min) was similar to that of nondiabetic patients (n = 54; 751 mL/min; Z = 1.31, P = 0.188). GPT values measured at three different dialysis session did not differ from each other that by Friedman test (F = 0.92, P = 0.39). This showed that GPT was stable and reliable. Glucose pump test can be used to measure blood flow rate of native AV fistula. GPT is an accurate and reliable test.

  4. Strength and Absorption Rate of Compressed Stabilized Earth Bricks (CSEBs Due to Different Mixture Ratios and Degree of Compaction

    Directory of Open Access Journals (Sweden)

    Abdullah Abd Halid

    2017-01-01

    Full Text Available Compressed Stabilized Earth Brick (CSEB is produced by compressing a mixture of water with three main materials such as Ordinary Portland Cement (OPC, soil, and sand. It becomes popularfor its good strength, better insulation properties, and a sustainable product due to its easy production with low carbon emission and less skilled labour required. Different types of local soils usedwill produce CSEB of different physical properties in terms of its strength, durability, and water absorption rate. This study focuses on laterite soil taken from the surrounding local area in Parit Raja, Johor, and CSEB samples are produced based on prototype brick size 100×50×30 mm. The investigations are based on four different degree of compactions (i.e. 1500, 2000, 2500, and 3000 Psi and three different mix proportion ratios of cement:sand:laterite soil (i.e. 1:1:9, 1:2:8, 1:3:7. A total of 144 CSEB samples have been tested at 7 and 28 days curing periods to determine the compressive strength (BS 3921:1985 and water absorption rate (MS 76:1972. It was found that maximum compressive strength of CSEB was 14.68 N/mm2 for mixture ratio of 1:3:7 at 2500 Psi compaction. Whereas, the minimum strengthis 6.87 N/mm2 for 1:1:9mixture ratio at 1500 Psi. Meanwhile, the lowest water absorption was 12.35% for mixture ratio of 1:2:8 at 3000 Psi; while the 1:1:9 mixture ratio at 1500 Psi gave the highest rate of 16.81%. This study affirms that the sand content in the mixture and the degree of compaction would affect the value of compressive strength and water absorption of CSEB.

  5. Estimation of salivary glucose, salivary amylase, salivary total protein and salivary flow rate in diabetics in India.

    Science.gov (United States)

    Panchbhai, Arati S; Degwekar, Shirish S; Bhowte, Rahul R

    2010-09-01

    Diabetes is known to influence salivary composition and function, eventually affecting the oral cavity. We thus evaluated saliva samples for levels of glucose, amylase and total protein, and assessed salivary flow rate in diabetics and healthy non-diabetics. We also analyzed these parameters with regard to duration and type of diabetes mellitus and gender, and aimed to assess the interrelationships among the variables included in the study. A total of 120 age- and sex-matched participants were divided into 3 groups of 40 each; the uncontrolled diabetic group, the controlled diabetic group and the healthy non-diabetic group. Salivary investigations were performed using unstimulated whole saliva. Mean salivary glucose levels were found to be significantly elevated in both uncontrolled and controlled diabetics, as compared to healthy non-diabetics. There were significant decreases in mean salivary amylase levels in controlled diabetics when compared to healthy non-diabetics. Other than salivary glucose, no other parameters were found to be markedly affected in diabetes mellitus. Further research is needed to explore the clinical implications of these study results.

  6. Definition of a parameter for a typical specific absorption rate under real boundary conditions of cellular phones in a GSM networkd

    Science.gov (United States)

    Gerhardt, D.

    2003-05-01

    Using cellular phones the specific absorption rate (SAR) as a physical value must observe established and internationally defined levels to guarantee human protection. To assess human protection it is necessary to guarantee safety under worst-case conditions (especially maximum transmitting power) using cellular phones. To evaluate the exposure to electromagnetic fields under normal terms of use of cellular phones the limitations of the specific absorption rate must be pointed out. In a mobile radio network normal terms of use of cellular phones, i.e. in interconnection with a fixed radio transmitter of a mobile radio network, power control of the cellular phone as well as the antenna diagram regarding a head phantom are also significant for the real exposure. Based on the specific absorption rate, the antenna diagram regarding a head phantom and taking into consideration the power control a new parameter, the typical absorption rate (SARtyp), is defined in this contribution. This parameter indicates the specific absorption rate under average normal conditions of use. Constant radio link attenuation between a cellular phone and a fixed radio transmitter for all mobile models tested was assumed in order to achieve constant field strength at the receiving antenna of the fixed radio transmitter as a result of power control. The typical specific absorption rate is a characteristic physical value of every mobile model. The typical absorption rate was calculated for 16 different mobile models and compared with the absorption rate at maximum transmitting power. The results confirm the relevance of the definition of this parameter (SARtyp) as opposed to the specific absorption rate as a competent and applicable method to establish the real mean exposure from a cellular phone in a mobile radio network. The typical absorption rate provides a parameter to assess electromagnetic fields of a cellular phone that is more relevant to the consumer.

  7. Impact of the reg1 mutation glycocen accumulation and glucose consumption rates in Saccharomyces cerevisiae cells based on a macrokinetic model

    Directory of Open Access Journals (Sweden)

    Rocha-Leão M.H.M.

    2003-01-01

    Full Text Available In S. cerevisiae, catabolite repression controls glycogen accumulation and glucose consumption. Glycogen is responsible for stress resistance, and its accumulation in derepression conditions results in a yeast with good quality. In yeast cells, catabolite repression also named glucose effect takes place at the transcriptional levels, decreasing enzyme respiration and causing the cells to enter a fermentative metabolism, low cell mass yield and yeast with poor quality. Since glucose is always present in molasses the glucose effect occurs in industrial media. A quantitative characterization of cell growth, substrate consumption and glycogen formation was undertaken based on an unstructured macrokinetic model for a reg1/hex2 mutant, capable of the respiration while growing on glucose, and its isogenic repressible strain (REG1/HEX2. The results show that the estimated value to maximum specific glycogen accumulation rate (muG,MAX is eight times greater in the reg1/hex2 mutant than its isogenic strain, and the glucose affinity constant (K SS is fifth times greater in reg1/hex2 mutant than in its isogenic strain with less glucose uptake by the former channeling glucose into cell mass growth and glycogen accumulation simultaneously. This approach may be one more tool to improve the glucose removal in yeast production. Thus, disruption of the REG1/HEX2 gene may constitute an important strategy for producing commercial yeast.

  8. Metabolism of the intervertebral disc: effects of low levels of oxygen, glucose, and pH on rates of energy metabolism of bovine nucleus pulposus cells.

    Science.gov (United States)

    Bibby, Susan R S; Jones, Deborah A; Ripley, Ruth M; Urban, Jill P G

    2005-03-01

    In vitro measurements of metabolic rates of isolated bovine nucleus pulposus cells at varying levels of oxygen, glucose, and pH. To obtain quantitative information on the interactions between oxygen and glucose concentrations and pH, and the rates of oxygen and glucose consumption and lactic acid production, for disc nucleus cells. Disc cells depend on diffusion from blood vessels at the disc margins for supply of nutrients. Loss of supply is thought to lead to disc degeneration, but how loss of supply affects nutrient concentrations in the disc is not known; nutrient concentrations within discs can normally only be calculated, because concentration measurements are invasive. However, realistic predictions cannot be made until there are data from measurements of metabolic rates at conditions found in the disc in vivo, i.e., at low levels of oxygen, glucose, and pH. A metabolism chamber was designed to allow simultaneous recording of oxygen and glucose concentrations and of pH. These concentrations were measured electrochemically with custom-built glucose and oxygen sensors; lactic acid was measured biochemically. Bovine nucleus pulposus cells were isolated and inserted into the chamber, and simultaneous rates of oxygen and glucose consumption and of lactic acid production were measured over a range of glucose, oxygen, and pH levels. There were strong interactions between rates of metabolism and oxygen consumption and pH. At atmospheric oxygen levels, oxygen consumption rate at pH 6.2 was 32% of that at pH 7.4. The rate fell by 60% as oxygen concentration was decreased from 21 to 5% at pH 7.4, but only by 20% at pH 6.2. Similar interactions were seen for lactic acid production and glucose consumption rates; we found that glycolysis rates fell at low oxygen and glucose concentrations and low pH. Equations were derived that satisfactorily predict the effect of nutrient and metabolite concentrations on rates of lactic acid production rate and oxygen consumption. Disc

  9. Sleep-Wake Differences in Relative Regional Cerebral Metabolic Rate for Glucose among Patients with Insomnia Compared with Good Sleepers

    Science.gov (United States)

    Kay, Daniel B.; Karim, Helmet T.; Soehner, Adriane M.; Hasler, Brant P.; Wilckens, Kristine A.; James, Jeffrey A.; Aizenstein, Howard J.; Price, Julie C.; Rosario, Bedda L.; Kupfer, David J.; Germain, Anne; Hall, Martica H.; Franzen, Peter L.; Nofzinger, Eric A.; Buysse, Daniel J.

    2016-01-01

    Study Objectives: The neurobiological mechanisms of insomnia may involve altered patterns of activation across sleep-wake states in brain regions associated with cognition, self-referential processes, affect, and sleep-wake promotion. The objective of this study was to compare relative regional cerebral metabolic rate for glucose (rCMRglc) in these brain regions across wake and nonrapid eye movement (NREM) sleep states in patients with primary insomnia (PI) and good sleeper controls (GS). Methods: Participants included 44 PI and 40 GS matched for age (mean = 37 y old, range 21–60), sex, and race. We conducted [18F]fluoro-2-deoxy-d-glucose positron emission tomography scans in PI and GS during both morning wakefulness and NREM sleep at night. Repeated measures analysis of variance was used to test for group (PI vs. GS) by state (wake vs. NREM sleep) interactions in relative rCMRglc. Results: Significant group-by-state interactions in relative rCMRglc were found in the precuneus/posterior cingulate cortex, left middle frontal gyrus, left inferior/superior parietal lobules, left lingual/fusiform/occipital gyri, and right lingual gyrus. All clusters were significant at Pcorrected sleep and wakefulness. Significant group-by-state interactions in relative rCMRglc suggest that insomnia is associated with impaired disengagement of brain regions involved in cognition (left frontoparietal), self-referential processes (precuneus/posterior cingulate), and affect (left middle frontal, fusiform/lingual gyri) during NREM sleep, or alternatively, to impaired engagement of these regions during wakefulness. Citation: Kay DB, Karim HT, Soehner AM, Hasler BP, Wilckens KA, James JA, Aizenstein HJ, Price JC, Rosario BL, Kupfer DJ, Germain A, Hall MH, Franzen PL, Nofzinger EA, Buysse DJ. Sleep-wake differences in relative regional cerebral metabolic rate for glucose among patients with insomnia compared with good sleepers. SLEEP 2016;39(10):1779–1794. PMID:27568812

  10. Rice (Oryza sativa japonica) Albumin Suppresses the Elevation of Blood Glucose and Plasma Insulin Levels after Oral Glucose Loading.

    Science.gov (United States)

    Ina, Shigenobu; Ninomiya, Kazumi; Mogi, Takashi; Hase, Ayumu; Ando, Toshiki; Matsukaze, Narumi; Ogihara, Jun; Akao, Makoto; Kumagai, Hitoshi; Kumagai, Hitomi

    2016-06-22

    The suppressive effect of rice albumin (RA) of 16 kDa on elevation of blood glucose level after oral loading of starch or glucose and its possible mechanism were examined. RA suppressed the increase in blood glucose levels in both the oral starch tolerance test and the oral glucose tolerance test. The blood glucose concentrations 15 min after the oral administration of starch were 144 ± 6 mg/dL for control group and 127 ± 4 mg/dL for RA 200 mg/kg BW group, while those after the oral administration of glucose were 157 ± 7 mg/dL for control group and 137 ± 4 mg/dL for RA 200 mg/kg BW group. However, in the intraperitoneal glucose tolerance test, no significant differences in blood glucose level were observed between RA and the control groups, indicating that RA suppresses the glucose absorption from the small intestine. However, RA did not inhibit the activity of mammalian α-amylase. RA was hydrolyzed to an indigestible high-molecular-weight peptide (HMP) of 14 kDa and low-molecular-weight peptides by pepsin and pancreatin. Furthermore, RA suppressed the glucose diffusion rate through a semipermeable membrane like dietary fibers in vitro. Therefore, the indigestible HMP may adsorb glucose and suppress its absorption from the small intestine.

  11. Calculation of induced current densities and specific absorption rates (SAR) for pregnant women exposed to hand-held metal detectors

    International Nuclear Information System (INIS)

    Kainz, Wolfgang; Chan, Dulciana D; Casamento, Jon P; Bassen, Howard I

    2003-01-01

    The finite difference time domain (FDTD) method in combination with a well established frequency scaling method was used to calculate the internal fields and current densities induced in a simple model of a pregnant woman and her foetus, when exposed to hand-held metal detectors. The pregnant woman and foetus were modelled using a simple semi-heterogeneous model in 10 mm resolution, consisting of three different types of tissue. The model is based on the scanned shape of a pregnant woman in the 34th gestational week. Nine different representative models of hand-held metal detectors operating in the frequency range from 8 kHz to 2 MHz were evaluated. The metal detectors were placed directly on the abdomen of the computational model with a spacing of 1 cm. Both the induced current density and the specific absorption rate (SAR) are well below the recommended limits for exposure of the general public published in the ICNIRP Guidelines and the IEEE C95.1 Standard. The highest current density is 8.3 mA m -2 and the highest SAR is 26.5 μW kg -1 . Compared to the limits for the induced current density recommended in the ICNIRP Guidelines, a minimum safety factor of 3 exists. Compared to the IEEE C95.1 Standard, a safety factor of 60,000 for the specific absorption rate was found. Based on the very low specific absorption rate and an induced current density below the recommended exposure limits, significant temperature rise or nerve stimulation in the pregnant woman or in the foetus can be excluded

  12. Variable food absorption by Antarctic krill: Relationships between diet, egestion rate and the composition and sinking rates of their fecal pellets

    Science.gov (United States)

    Atkinson, A.; Schmidt, K.; Fielding, S.; Kawaguchi, S.; Geissler, P. A.

    2012-01-01

    The kinetics of food processing by zooplankton affects both their energy budgets and the biogeochemical fate of their fecal pellets. We sampled 40 schools of krill across the Scotia Sea during spring, summer and autumn and found that in all 3 seasons, every aspect of their absorption and defecation varied greatly. The C content of fecal pellets varied from 0.85% to 29% of their dry mass (median 9.8%) and C egestion rates varied 75-fold. C:N mass ratios of pellets ranged from 4.9 to 13.2 (median 7.8), higher than values of 3.9 in the krill and 5.4 in their food, pointing to enhanced uptake of N. Pellet sinking rates equated to 27-1218 m d -1 (median 304 m d -1), being governed mainly by pellet diameter (80-600 μm, mean 183 μm) and density (1.038-1.391 g cm -3, mean 1.121 g cm -3). Pellets showed little loss of C or N in filtered seawater over the first 2 days and were physically robust. When feeding rates were low, slow gut passage time and high absorption efficiency resulted in low egestion rates of pellets that were low in C and N content. These pellets were compact, dense and fast-sinking. Conversely, in good feeding conditions much food tended to pass quickly through the gut and was not efficiently absorbed, producing C and N-rich, slow-sinking pellets. Such "superfluous feeding" probably maximises the absolute rates of nutrient absorption. Food composition was also important: diatom-rich diets depressed the C content of the pellets but increased their sinking rates, likely due to silica ballasting. So depending on how krill process food, their pellets could represent both vehicles for rapid export and slow sinking, C and N-rich food sources for pelagic scavengers. C egestion rates by krill averaged 3.4% of summer primary production (and ingestion rates would be 2-10-fold higher than this) so whatever the fate of the pellets, krill are an important re-packager within the food web. While salp pellets tend to sink faster than those of krill, it is the latter

  13. On the relationship between glucose absorption and glucose‐stimulated secretion of GLP‐1, neurotensin, and PYY from different intestinal segments in the rat

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Christiansen, Charlotte Bayer; Saltiel, Monika Yosifova

    2017-01-01

    luminal glucose (20%, w/v) increased GLP‐1 and NT secretion five to eightfold compared to basal secretion. Compared to the USI, basal and stimulated GLP‐1 secretion from the colon was 8–10 times lower and no NT secretion was detected. Luminal glucose stimulated secretion of PYY four to fivefold from......Ingested glucose powerfully stimulates the secretion of appetite‐ and metabolism‐regulating peptide hormones from the gut – including glucagon‐like peptide‐1 (GLP‐1), neurotensin (NT), and polypeptide YY (PYY). However, the regional origin of these secretions after glucose stimulation is not well...

  14. Metabolome analysis-based design and engineering of a metabolic pathway in Corynebacterium glutamicum to match rates of simultaneous utilization of D-glucose and L-arabinose.

    Science.gov (United States)

    Kawaguchi, Hideo; Yoshihara, Kumiko; Hara, Kiyotaka Y; Hasunuma, Tomohisa; Ogino, Chiaki; Kondo, Akihiko

    2018-05-17

    L-Arabinose is the second most abundant component of hemicellulose in lignocellulosic biomass, next to D-xylose. However, few microorganisms are capable of utilizing pentoses, and catabolic genes and operons enabling bacterial utilization of pentoses are typically subject to carbon catabolite repression by more-preferred carbon sources, such as D-glucose, leading to a preferential utilization of D-glucose over pentoses. In order to simultaneously utilize both D-glucose and L-arabinose at the same rate, a modified metabolic pathway was rationally designed based on metabolome analysis. Corynebacterium glutamicum ATCC 31831 utilized D-glucose and L-arabinose simultaneously at a low concentration (3.6 g/L each) but preferentially utilized D-glucose over L-arabinose at a high concentration (15 g/L each), although L-arabinose and D-glucose were consumed at comparable rates in the absence of the second carbon source. Metabolome analysis revealed that phosphofructokinase and pyruvate kinase were major bottlenecks for D-glucose and L-arabinose metabolism, respectively. Based on the results of metabolome analysis, a metabolic pathway was engineered by overexpressing pyruvate kinase in combination with deletion of araR, which encodes a repressor of L-arabinose uptake and catabolism. The recombinant strain utilized high concentrations of D-glucose and L-arabinose (15 g/L each) at the same consumption rate. During simultaneous utilization of both carbon sources at high concentrations, intracellular levels of phosphoenolpyruvate declined and acetyl-CoA levels increased significantly as compared with the wild-type strain that preferentially utilized D-glucose. These results suggest that overexpression of pyruvate kinase in the araR deletion strain increased the specific consumption rate of L-arabinose and that citrate synthase activity becomes a new bottleneck in the engineered pathway during the simultaneous utilization of D-glucose and L-arabinose. Metabolome analysis

  15. The corrosion rate and the hydrogen absorption behavior of titanium under reducing condition-III. Research document

    International Nuclear Information System (INIS)

    Suzuki, H.; Taniguchi, N.; Kawakami, S.

    2005-03-01

    Titanium is one of the candidate materials for overpacks as a high corrosion resistance metal. At the initial stage of repository, oxidizing condition will be given around the overpack because oxygen will be brought from the ground. The oxygen will be consumed by the reaction with impurities in buffer material or corrosion of overpack, and reducing condition will be achieved around the overpack. With the changing of redox condition, the water reduction becomes to dominate the cathodic reaction accompanying hydrogen generation. Crevice corrosion and hydrogen embrittlement are main causes of the damage of long term integrity of titanium overpack. However, it is not known about the corrosion resistance and hydrogen absorption behavior of titanium under reduction condition. In this study, the completely sealed ampoule test and the immersion test of titanium in aqueous solution and bentonite was carried out. In order to obtain reliable data about the hydrogen generation rate and the ratio of hydrogen absorption in titanium. From the result of 3 years immersion tests, corrosion rate of titanium were estimated to be in the order of 10 -2 ∼10 -1 μm/y in the aqueous solution, and 10 -3 ∼10 -2 μm/y in bentonite. This value is almost the same as the last report. Almost all the hydrogen generated by corrosion was absorbed in titanium in the immersion tests in completely sealed ampoule. In the examination that changed each parameter, it was suggested that the amount of the hydrogen absorption become 2∼3 times in 1M HCO 3- and pH13. (author)

  16. Magnetic nanoparticles with high specific absorption rate of electromagnetic energy at low field strength for hyperthermia therapy

    Science.gov (United States)

    Shubitidze, Fridon; Kekalo, Katsiaryna; Stigliano, Robert; Baker, Ian

    2015-03-01

    Magnetic nanoparticles (MNPs), referred to as the Dartmouth MNPs, which exhibit high specific absorption rate at low applied field strength have been developed for hyperthermia therapy applications. The MNPs consist of small (2-5 nm) single crystals of gamma-Fe2O3 with saccharide chains implanted in their crystalline structure, forming 20-40 nm flower-like aggregates with a hydrodynamic diameter of 110-120 nm. The MNPs form stable (>12 months) colloidal solutions in water and exhibit no hysteresis under an applied quasistatic magnetic field, and produce a significant amount of heat at field strengths as low as 100 Oe at 99-164 kHz. The MNP heating mechanisms under an alternating magnetic field (AMF) are discussed and analyzed quantitatively based on (a) the calculated multi-scale MNP interactions obtained using a three dimensional numerical model called the method of auxiliary sources, (b) measured MNP frequency spectra, and (c) quantified MNP friction losses based on magneto-viscous theory. The frequency responses and hysteresis curves of the Dartmouth MNPs are measured and compared to the modeled data. The specific absorption rate of the particles is measured at various AMF strengths and frequencies, and compared to commercially available MNPs. The comparisons demonstrate the superior heating properties of the Dartmouth MNPs at low field strengths (therapy to deeper tumors that were previously non-viable targets, potentially enabling the treatment of some of the most difficult cancers, such as pancreatic and rectal cancers, without damaging normal tissue.

  17. Noninvasive and simple method for the estimation of myocardial metabolic rate of glucose by PET and 18F-FDG

    International Nuclear Information System (INIS)

    Takahashi, Norio; Tamaki, Nagara; Kawamoto, Masahide

    1994-01-01

    To estimate regional myocardial metabolic rate of glucose (rMRGlu) with positron emission tomography (PET) and 2-[ 18 F] fluoro-2-deoxy-D-glucose (FDG), non invasive simple method has been investigated using dynamic PET imaging in 14 patients with ischemic heart disease. This imaging approach uses a blood time-activity curve (TAC) derived from a region of interest (ROI) drawn over dynamic PET images of the left ventricle (LV), left atrium (LA) and aorta. Patlak graphic analysis was used to estimate k 1 k 3 /(k 2 +k 3 ) from serial plasma and myocardial radioactivities. FDG counts ratio between whole blood and plasma was relatively constant (0.91±0.02) both throughout the time and among different patients. Although TACs derived from dynamic PET images gradually increased at later phase due to spill over from the myocardium into the cavity, three were good agreements between the estimated K complex values obtained from arterial blood sampling and dynamic PET imaging (LV r=0.95, LA r=0.96, aorta r=0.98). These results demonstrate the practical usefulness of a simplified and noninvasive method for the estimation of rMRGlu in humans by PET. (author)

  18. An experimental investigation of the rate of hydrogen absorption in zirconium-2.5 wt percent niobium from steam/hydrogen mixtures at elevated temperatures

    International Nuclear Information System (INIS)

    Langman, V.J.

    1984-08-01

    The test specifications for an experimental program to study the rate of hydrogen absorption in zirconium-2.5 weight percent niobium pressure tube material from steam/hydrogen mixtures at elevated temperatures are discussed

  19. Loss of insulin response to glucose but not arginine during the development of autoimmune diabetes in BB/W rats: relationships to islet volume and glucose transport rate.

    OpenAIRE

    Tominaga, M; Komiya, I; Johnson, J H; Inman, L; Alam, T; Moltz, J; Crider, B; Stefan, Y; Baetens, D; McCorkle, K

    1986-01-01

    The insulin and glucagon responses to 10 mM glucose and 10 mM arginine were studied in pancreata isolated from nondiabetic diabetes-prone and diabetes-resistant BB/W rats at 60, 80, and 140 days of age and in diabetic BB/W rats on the 1st and 14th days of their diabetes. In the former group the insulin response to glucose declined progressively with age (r = -0.575; P less than 0.01) and at 140 days was significantly below age-matched diabetes-resistant controls (P less than 0.05). The insuli...

  20. Bile Acid Sequestration Reduces Plasma Glucose Levels in db/db Mice by Increasing Its Metabolic Clearance Rate

    NARCIS (Netherlands)

    Meissner, M.; Herrema, H.J.; Dijk, van Th.; Gerding, A.; Havinga, R.; Boer, T.; Müller, M.R.; Reijngoud, D.J.; Groen, A.K.; Kuipers, F.

    2011-01-01

    Aims/Hypothesis: Bile acid sequestrants (BAS) reduce plasma glucose levels in type II diabetics and in murine models of diabetes but the mechanism herein is unknown. We hypothesized that sequestrant-induced changes in hepatic glucose metabolism would underlie reduced plasma glucose levels.

  1. Metabolic Profiling Reveals Differences in Plasma Concentrations of Arabinose and Xylose after Consumption of Fiber-Rich Pasta and Wheat Bread with Differential Rates of Systemic Appearance of Exogenous Glucose in Healthy Men.

    Science.gov (United States)

    Pantophlet, Andre J; Wopereis, Suzan; Eelderink, Coby; Vonk, Roel J; Stroeve, Johanna H; Bijlsma, Sabina; van Stee, Leo; Bobeldijk, Ivana; Priebe, Marion G

    2017-02-01

    The consumption of products rich in cereal fiber and with a low glycemic index is implicated in a lower risk of metabolic diseases. Previously, we showed that the consumption of fiber-rich pasta compared with bread resulted in a lower rate of appearance of exogenous glucose and a lower glucose clearance rate quantified with a dual-isotope technique, which was in accordance with a lower insulin and glucose-dependent insulinotropic polypeptide response. To gain more insight into the acute metabolic consequences of the consumption of products resulting in differential glucose kinetics, postprandial metabolic profiles were determined. In a crossover study, 9 healthy men [mean ± SEM age: 21 ± 0.5 y; mean ± SEM body mass index (kg/m 2 ): 22 ± 0.5] consumed wheat bread (132 g) and fresh pasta (119 g uncooked) enriched with wheat bran (10%) meals. A total of 134 different metabolites in postprandial plasma samples (at -5, 30, 60, 90, 120, and 180 min) were quantified by using a gas chromatography-mass spectrometry-based metabolomics approach (secondary outcomes). Two-factor ANOVA and advanced multivariate statistical analysis (partial least squares) were applied to detect differences between both food products. Forty-two different postprandial metabolite profiles were identified, primarily representing pathways related to protein and energy metabolism, which were on average 8% and 7% lower after the men consumed pasta rather than bread, whereas concentrations of arabinose and xylose were 58% and 53% higher, respectively. Arabinose and xylose are derived from arabinoxylans, which are important components of wheat bran. The higher bioavailability of arabinose and xylose after pasta intake coincided with a lower rate of appearance of glucose and amino acids. We speculate that this higher bioavailability is due to higher degradation of arabinoxylans by small intestinal microbiota, facilitated by the higher viscosity of arabinoxylans after pasta intake than after bread

  2. Glucose Pump Test can be Used to Measure Blood Flow Rate of ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... In 93 chronic hemodialysis patients with native AV fistula, blood flow rates were measured by Doppler US .... Arterial blood pressure from nonvascular access arm was measured by aneroid sphygmomanometer. The patients did not .... to detect differences in treatments across multiple test attempts. P < 0.05 ...

  3. Pressure effect on rate of production of glucose-equivalent in plant ...

    Indian Academy of Sciences (India)

    Administrator

    C4 Green plants; rate of equivalent production; pressure effect. 1. Introduction ... the photosynthetic process, especially on the activa- tion and ... Section 4 deals with the effect ... the global concentrations of glyceraldehydes-3- ... chloroplast,9a a product of the maximum possible .... as soil, tissue, development stage, etc.

  4. Non-invasive Estimation of Metabolic Uptake Rate of Glucose using F18-FDG PET and Linear Transformation of Outputs

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark; Reichkendler, M.; Auerback, P.

    For quantitative analysis and kinetic modeling of dynamic PET-data an input function is needed. Normally this is obtained by arterial blood sampling, potentially an unpleasant experience for the patient and laborious for the staff. Aim: To validate methods for determination of the metabolic uptake...... rate (Km) of glucose from dynamic FDG-PET scans using Image Derived Input Functions (IDIF) without blood sampling. Method: We performed 24 dynamic FDG-PET scans of the thigh of 14 healthy young male volunteers during a hyperinsulinemic isoglycemic clamp. Ten of the subjects were scanned twice 11 weeks...... artery diameter in the material, the method should also be applicable to women and people of other ages, but used with caution in the elderly due to variance in intramuscular adipose distribution. If only Km and no other kinetic parameters are needed, the described method with transformation...

  5. [Measurement of regional cerebral metabolism rate of glucose in patients with Alzheimer's disease in different levels of severity].

    Science.gov (United States)

    Xiao, Shi-fu; Cao, Qiu-yun; Xue, Hai-bo; Liu, Yong-chang; Zuo, Chuan-tao; Jiang, Kai-da; Zhang, Ming-yuan

    2005-11-09

    To measure the changes of regional cerebral metabolism rate of glucose (rCMRglc) in patients with Alzheimer's disease (AD) and explore their value to diagnosis of AD. 10 patients with AD who met the diagnostic criteria of DSM-IV and 10 normal controls (NC) were assessed with (18)F-2-fluoro-deoxy-D-glucose positron emission tomography (PET). The two groups were matched in age, gender and education. The mean total scores of the mini-mental status examination (MMSE) were 16.5 +/- 6.1 for AD and 28.7 +/- 1.6 for NC. The mean total memory quotient of Wechsler Memory Scales (MQ) were 32.3 +/- 19.6 for AD and 93.1 +/- 9.0 for NC. Comparing to NC, the AD groups showed statistically significant decline of rCMRglc in frontal lobe, temporal lobe and the hippocampal formation with decreased rates ranged from 3.3% to 28.4% (P upper and middle frontal gyri, middle temporal gyrus, orbital gyrus and anterior cingulate gyrus, in which areas the metabolism decreased over 20% compared to NC. The hypo-metabolism was correlated to the severity of dementia. Discriminant analysis demonstrated that the variables of right inferior temporal gyrus, left upper temporal gyrus, left hippocampus and right insular lobe were entered into the discriminant functions and the total discriminant accuracy reached 100%. (18)F-FDG PET is a very sensitive tool in measurement of the changes of rCMRglc in patients with AD. The findings show a frontal-temporal type of metabolism in AD patients and suggest that hypo-metabolism in hippocampal formation and temporal lobe is helpful in early detection of AD.

  6. 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.

  7. FDTD chiral brain tissue model for specific absorption rate determination under radiation from mobile phones at 900 and 1800 MHz

    Energy Technology Data Exchange (ETDEWEB)

    Zamorano, M; Torres-Silva, H [Departamento de Electronica, Universidad de Tarapaca, 18 de Septiembre 2222, Arica (Chile)

    2006-04-07

    A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) 'inverse skin effect' shows up at 1800 MHz, with respect to a 900 MHz source.

  8. Combined heart rate- and accelerometer-assessed physical activity energy expenditure and associations with glucose homeostasis markers in a population at high risk of developing diabetes

    DEFF Research Database (Denmark)

    Hansen, Anne-Louise Smidt; Carstensen, Bendix; Helge, Jørn Wulff

    2013-01-01

    OBJECTIVE: Regular physical activity (PA) reduces the risk of developing type 2 diabetes, and different subtypes of dysglycemia have shown different associations with PA. To better understand the associations of PA and glucose homeostasis, we examined the association of objectively measured PA...... energy expenditure (PAEE) with detailed measures of glucose homeostasis. RESEARCH DESIGN AND METHODS: In 1,531 men and women, with low to high risk of developing type 2 diabetes, we measured 7 days of PAEE using a combined accelerometry and heart rate monitor (ActiHeart). Measures and indices of glucose...... of PAEE slightly in an entire population at risk for developing type 2 diabetes may be a realistic and worthwhile goal to reach in order to achieve beneficial effect in terms of glucose metabolism....

  9. A wide-frequency range AC magnetometer to measure the specific absorption rate in nanoparticles for magnetic hyperthermia

    International Nuclear Information System (INIS)

    Garaio, E.; Collantes, J.M.; Garcia, J.A.; Plazaola, F.; Mornet, S.; Couillaud, F.; Sandre, O.

    2014-01-01

    Measurement of specific absorption rate (SAR) of magnetic nanoparticles is crucial to assert their potential for magnetic hyperthermia. To perform this task, calorimetric methods are widely used. However, those methods are not very accurate and are difficult to standardize. In this paper, we present AC magnetometry results performed with a lab-made magnetometer that is able to obtain dynamic hysteresis-loops in the AC magnetic field frequency range from 50 kHz to 1 MHz and intensities up to 24 kA m −1 . In this work, SAR values of maghemite nanoparticles dispersed in water are measured by AC magnetometry. The so-obtained values are compared with the SAR measured by calorimetric methods. Both measurements, by calorimetry and magnetometry, are in good agreement. Therefore, the presented AC magnetometer is a suitable way to obtain SAR values of magnetic nanoparticles. - Highlights: • We propose AC magnetometry as a method to measure the specific absorption rate (SAR) of magnetic nanoparticles suitable for magnetic hyperthermia therapy. • We have built a lab-made AC magnetometer, which is able to measure magnetic dynamic hysteresis-loops of nanoparticle dispersions. • The device works with AC magnetic field intensities up to 24 kA m −1 in a frequency range from 75 kHz to 1 MHz. • The SAR values of maghemite nanoparticles around 12 nm in magnetic diameter dispersed in water are measured by the lab-made magnetometer and different calorimetric methods. • Although all methods are in good agreement, several factors (probe location, thermal inertia, losses, etc.) make calorimetric method less accurate than AC magnetometry

  10. Effect of postprandial hyperglycaemia in non-invasive measurement of cerebral metabolic rate of glucose in non-diabetic subjects

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchida, Tatsuro; Itoh, Harumi [Department of Radiology, Fukui Medical University, Matsuoka (Japan); Sadato, Norihiro; Nishizawa, Sadahiko; Yonekura, Yoshiharu [Biomedical Imaging Research Center, Fukui Medical University (Japan)

    2002-02-01

    The aim of this study was to determine the effect of postprandial hyperglycaemia (HG) on the non-invasive measurement of cerebral metabolic rate of glucose (CMRGlc). Five patients who had a meal within an hour before a fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) examination were recruited in this study. They underwent intermittent arterial blood sampling (measured input function), and, based on this sampling, CMRGlc was calculated using an autoradiographic method (CMRGlc{sub real}). Simulated input functions were generated based on standardised input function, body surface area and net injected dose of FDG, and simulated CMRGlc (CMRGlc{sub sim}) was also calculated. Percent error of the area under the curve (AUC) between measured (AUC{sub real}) and simulated input function (AUC{sub IFsim}) and percent error between CMRGlc{sub real} and CMRGlc{sub sim} were calculated. These values were compared with those obtained from a previous study conducted under fasting conditions (F). The serum glucose level in the HG group was significantly higher than that in the F group (165{+-}69 vs 100{+-}9 mg/dl, P=0.0007). Percent errors of AUC and CMRGlc in grey matter and white matter in HG were significantly higher than those in F (12.9%{+-}1.3% vs 3.5%{+-}2.2% in AUC, P=0.0015; 18.2%{+-}2.2% vs 2.9%{+-}1.9% in CMRGlc in grey matter, P=0.0028; 24.0%{+-}4.6% vs 3.4%{+-}2.2% in CMRGlc in white matter, P=0.0028). It is concluded that a non-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions. (orig.)

  11. Effect of postprandial hyperglycaemia in non-invasive measurement of cerebral metabolic rate of glucose in non-diabetic subjects

    International Nuclear Information System (INIS)

    Tsuchida, Tatsuro; Itoh, Harumi; Sadato, Norihiro; Nishizawa, Sadahiko; Yonekura, Yoshiharu

    2002-01-01

    The aim of this study was to determine the effect of postprandial hyperglycaemia (HG) on the non-invasive measurement of cerebral metabolic rate of glucose (CMRGlc). Five patients who had a meal within an hour before a fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) examination were recruited in this study. They underwent intermittent arterial blood sampling (measured input function), and, based on this sampling, CMRGlc was calculated using an autoradiographic method (CMRGlc real ). Simulated input functions were generated based on standardised input function, body surface area and net injected dose of FDG, and simulated CMRGlc (CMRGlc sim ) was also calculated. Percent error of the area under the curve (AUC) between measured (AUC real ) and simulated input function (AUC IFsim ) and percent error between CMRGlc real and CMRGlc sim were calculated. These values were compared with those obtained from a previous study conducted under fasting conditions (F). The serum glucose level in the HG group was significantly higher than that in the F group (165±69 vs 100±9 mg/dl, P=0.0007). Percent errors of AUC and CMRGlc in grey matter and white matter in HG were significantly higher than those in F (12.9%±1.3% vs 3.5%±2.2% in AUC, P=0.0015; 18.2%±2.2% vs 2.9%±1.9% in CMRGlc in grey matter, P=0.0028; 24.0%±4.6% vs 3.4%±2.2% in CMRGlc in white matter, P=0.0028). It is concluded that a non-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions. (orig.)

  12. Ex-vivo glucose sensors using micro-dialysis: importance of on-line recovery rate determination by multi-analyte infrared spectrometry

    Science.gov (United States)

    Vahlsing, Thorsten; Delbeck, Sven; Budde, Janpeter; Cocchieri, Lars; Ihrig, Dieter; Leonhardt, Steffen; Heise, H. M.

    2015-03-01

    Micro-dialysis has been established in the clinical environment for continuously harvesting body fluids, but a drawback of this process are variable recovery rates, which can be observed especially for subcutaneously implanted catheters. Perfusates with either acetate or mannitol have been investigated as recovery markers. The latter substance is suggested for application with external cavity tuneable quantum cascade lasers, rendering a limited wavenumber interval in contrast to FTIR-spectrometers. Despite the overlap of mannitol and glucose spectra, their simultaneous quantification was successful. By investigating the depletion of the marker substances from the perfusates using different micro-dialysis devices, the theoretical nonlinear relationship between the relative dialysate marker concentration and glucose recovery rate was confirmed for the marker substance-analyte pair of acetate and glucose, rendering a basis for reliable blood glucose measurements. For the pair of mannitol and glucose an almost linear dependency was expected for the microdialysate catheters and experimentally verified, which provides a straightforward correction of any dialysis recovery rate variation during patient monitoring.

  13. The Glucagon-Like Peptide-1 Analog Exenatide Increases Blood Glucose Clearance, Lactate Clearance, and Heart Rate in Comatose Patients After Out-of-Hospital Cardiac Arrest

    DEFF Research Database (Denmark)

    Wiberg, Sebastian; Kjaergaard, Jesper; Schmidt, Henrik

    2018-01-01

    the first 6 hours from study drug initiation: lactate level, blood glucose level, heart rate, mean arterial pressure, and combined dosage of norepinephrine and dopamine. MEASUREMENTS AND MAIN RESULTS: The population consisted of 106 patients receiving either exenatide or placebo. During the first 6 hours...... from study drug initiation, the levels of blood glucose and lactate decreased 17% (95% CI, 8.9-25%; p = 0.0004) and 21% (95% CI, 6.0-33%; p = 0.02) faster in patients receiving exenatide versus placebo, respectively. Exenatide increased heart rate by approximately 10 beats per minute compared......OBJECTIVES: To investigate the effects of the glucagon-like peptide-1 analog exenatide on blood glucose, lactate clearance, and hemodynamic variables in comatose, resuscitated out-of-hospital cardiac arrest patients. DESIGN: Predefined post hoc analyzes from a double-blind, randomized clinical...

  14. Noninvasive quantification of cerebral metabolic rate for glucose in rats using 18F-FDG PET and standard input function

    Science.gov (United States)

    Hori, Yuki; Ihara, Naoki; Teramoto, Noboru; Kunimi, Masako; Honda, Manabu; Kato, Koichi; Hanakawa, Takashi

    2015-01-01

    Measurement of arterial input function (AIF) for quantitative positron emission tomography (PET) studies is technically challenging. The present study aimed to develop a method based on a standard arterial input function (SIF) to estimate input function without blood sampling. We performed 18F-fluolodeoxyglucose studies accompanied by continuous blood sampling for measurement of AIF in 11 rats. Standard arterial input function was calculated by averaging AIFs from eight anesthetized rats, after normalization with body mass (BM) and injected dose (ID). Then, the individual input function was estimated using two types of SIF: (1) SIF calibrated by the individual's BM and ID (estimated individual input function, EIFNS) and (2) SIF calibrated by a single blood sampling as proposed previously (EIF1S). No significant differences in area under the curve (AUC) or cerebral metabolic rate for glucose (CMRGlc) were found across the AIF-, EIFNS-, and EIF1S-based methods using repeated measures analysis of variance. In the correlation analysis, AUC or CMRGlc derived from EIFNS was highly correlated with those derived from AIF and EIF1S. Preliminary comparison between AIF and EIFNS in three awake rats supported an idea that the method might be applicable to behaving animals. The present study suggests that EIFNS method might serve as a noninvasive substitute for individual AIF measurement. PMID:25966947

  15. Acute effects of the glucagon-like peptide-1 receptor agonist, exenatide, on blood pressure and heart rate responses to intraduodenal glucose infusion in type 2 diabetes.

    Science.gov (United States)

    Thazhath, Sony S; Marathe, Chinmay S; Wu, Tongzhi; Chang, Jessica; Khoo, Joan; Kuo, Paul; Checklin, Helen L; Bound, Michelle J; Rigda, Rachael S; Horowitz, Michael; Jones, Karen L; Rayner, Christopher K

    2017-01-01

    To evaluate the effects of the glucagon-like peptide-1 receptor agonist, exenatide, on blood pressure and heart rate during an intraduodenal glucose infusion in type 2 diabetes. Nine subjects with type 2 diabetes were randomised to receive intravenous exenatide or saline control in a crossover design. Glucose (3 kcal min -1 ) was infused via an intraduodenal manometry catheter for 60 min. Blood pressure, heart rate, and the frequency and amplitude of duodenal pressure waves were measured at regular intervals. Gastrointestinal symptoms were monitored using 100 mm visual analogue scales. During intraduodenal glucose infusion (0-60 min), diastolic (p (0-60)  = 0.03) and mean arterial (p (0-60)  = 0.03) blood pressures and heart rate (p (0-60)  = 0.06; p (0-120)  = 0.03)) were higher with exenatide compared to placebo. The increase in the area under the curve for diastolic blood pressure and mean arterial blood pressure was related directly to the suppression of the duodenal motility index with exenatide compared to control (p = 0.007 and 0.04, respectively). In type 2 diabetes, intravenous exenatide increases mean arterial blood pressure and heart rate during an intraduodenal glucose infusion, supporting the need for further research with exenatide for its potential use in postprandial hypotension. © The Author(s) 2016.

  16. Glucose Injections into the Dorsal Hippocampus or Dorsolateral Striatum of Rats Prior to T-Maze Training: Modulation of Learning Rates and Strategy Selection

    Science.gov (United States)

    Canal, Clinton E.; Stutz, Sonja J.; Gold, Paul E.

    2005-01-01

    The present experiments examined the effects of injecting glucose into the dorsal hippocampus or dorsolateral striatum on learning rates and on strategy selection in rats trained on a T-maze that can be solved by using either a hippocampus-sensitive place or striatum-sensitive response strategy. Percentage strategy selection on a probe trial…

  17. Influence of filtration and glucose amendment on bacterial growth rate at different tidal conditions in the Minho Estuary River (NW Portugal)

    DEFF Research Database (Denmark)

    Anne, I.; Fidalgo, M. L.; Thosthrup, L.

    2006-01-01

    Bacterioplankton abundance, biomass and growth rates were studied in the Minho Estuary River (NW Portugal). The influence of tidal conditions, glucose amendment, and the filtration process on total bacterial abundance, total and faecal coliforms, as well as faecal streptococci, were evaluated...

  18. Calibrated image-derived input functions for the determination of the metabolic uptake rate of glucose with [18F]-FDG PET

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark; Reichkendler, Michala H.; Larsen, Rasmus

    2014-01-01

    We investigated the use of a simple calibration method to remove bias in previously proposed approaches to image-derived input functions (IDIFs) when used to calculate the metabolic uptake rate of glucose (Km) from dynamic [18F]-FDG PET scans of the thigh. Our objective was to obtain nonbiased, low...

  19. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  20. Prevalence of positive urinary dipstick analysis (leucocyte esterase, nitrite, haemoglobin, or glucose) in a population of 3645 adult subjects--consequence for measurement of urinary albumin excretion rate

    DEFF Research Database (Denmark)

    Clausen, P; Jensen, J S; Borch-Johnsen, K

    1998-01-01

    OBJECTIVES: To assess prevalence of positive urinary dipstick analysis for leucocyte esterase, nitrite, haemoglobin, or glucose in the general population and measure the urinary albumin excretion rate (UAER) in subjects with or without a positive dipstick analysis. DESIGN: A cross-sectional study...... of 3645 subjects. SETTING: An unselected urban population study. MAIN OUTCOME MEASURES: Prevalence data of positive dipstick analyses and UAER values. RESULTS: Prevalence data of a positive dipstick analysis were 12%, 4%, 3% and 6%, respectively, for leucocyte esterase, nitrite, haemoglobin, and glucose...

  1. Poster - Thur Eve - 13: Quantifying specific absorption rate of shielded RF coils through electromagnetic simulations for 7-T MRI.

    Science.gov (United States)

    Belliveau, J-G; Gilbert, K M; Abou-Khousa, M; Menon, R S

    2012-07-01

    Ultra-high field MRI has many advantages such as increasing spatial resolution and exploiting contrast never before seen in-vivo. This contrast has been shown to be beneficial for many applications such as monitoring early and late effect to radiation therapy and transient changes during disease to name a few. However, at higher field strengths the RF wave, needed to for transmitting and receiving signal, approaches that of the head. This leads to constructive and deconstructive interference and a non -uniform flip angle over the volume being imaged. A transmit or transceive RF surface coil arrays is currently a method of choice to overcome this problem; however, mutual inductance between elements poses a significant challenge for the designer. A method to decouple elements in such an array is by using circumferential shielding; however, the potential benefits and/or disadvantages have not been investigated. This abstract primarily focuses on understanding power deposition - measured through Specific Absorption Rate - in the sample using circumferentially shielded RF coils. Various geometries of circumferentially shielded coils are explored to determine the behaviour of shield width and its effect on required transmit power and power deposition to the sample. Our results indicate that there is an optimization on shield width depending on the imaging depth. Additionally, the circumferential shield focuses the field more than unshielded coils, meaning that slight SAR may even be lower for circumferential shielded RF coils in array. © 2012 American Association of Physicists in Medicine.

  2. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry)

    Science.gov (United States)

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-01

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the ‘specific absorption rate (SAR)’, is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 {}^\\circ C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m-1 in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  3. Total Absorption Spectroscopy Study of the Beta Decay of 60Mn to Constrain the Neutron Capture Rate of 60Fe

    Science.gov (United States)

    Richman, Debra; Spyrou, Artemis; Dombos, Alex; Couture, Aaron; e15034 Collaboration

    2017-09-01

    Interest in 60Fe, a long lived radioisotope synthesized in massive stars, has recently peaked. The signature of its decay allows us to probe astrophysical processes, events such as the early formation of the solar system and nucleosynthesis. To understand these observations a complete understanding of the creation, destruction and nuclear properties of 60Fe in the astrophysical environment are required. Using the beta decay of 60Mn in conjunction with total absorption spectroscopy (TAS), made possible by the high efficiency gamma ray calorimeter SuN (Summing NaI detector) at the National Superconducting Cyclotron Laboratory (NSCL), to study the distribution of beta-decay intensity over the daughter-nucleus 60Fe, provides information about the structure of the daughter and improves the predictive power of astrophysical models. In addition to the ongoing TAS analysis, The Beta-Oslo method will be used to extract the nuclear level density and gamma-strength function of 60Fe providing much needed constraints on the neutron capture reaction rate responsible for the creation of this nucleus.

  4. Contrast-enhanced specific absorption rate-efficient 3D cardiac cine with respiratory-triggered radiofrequency gating.

    Science.gov (United States)

    Henningsson, Markus; Chan, Raymond H; Goddu, Beth; Goepfert, Lois A; Razavi, Reza; Botnar, Rene M; Schaeffter, Tobias; Nezafat, Reza

    2013-04-01

    To investigate the use of radiofrequency (RF) gating in conjunction with a paramagnetic contrast agent to reduce the specific absorption rate (SAR) and increase the blood-myocardium contrast in balanced steady-state free precession (bSSFP) 3D cardiac cine. RF gating was implemented by synchronizing the RF-excitation with an external respiratory sensor (bellows), which could additionally be used for respiratory gating. For reference, respiratory-gated 3D cine images were acquired without RF gating. Free-breathing 3D cine images were acquired in eight healthy subjects before and after contrast injection (Gd-BOPTA) and compared to breath-hold 2D cine. RF-gated 3D cine reduced the SAR by nearly 40% without introducing significant artifacts while providing left ventricle (LV) measurements similar to those obtained with 2D cine. The contrast-to-noise ratio (CNR) was significantly higher for 3D cine compared to 2D cine, both before and after contrast injection; however, no statistically significant CNR increase was observed for the postcontrast 3D cine compared to the precontrast acquisitions. Respiratory-triggered RF gating significantly reduces SAR in 3D cine acquisitions, which may enable a more widespread clinical use of 3D cine. Furthermore, CNR of 3D bSSFP cine is higher than of 2D and administration of Gd-BOPTA does not improve the CNR of 3D cine. Copyright © 2012 Wiley Periodicals, Inc.

  5. Effects of posture on FDTD calculations of specific absorption rate in a voxel model of the human body

    International Nuclear Information System (INIS)

    Findlay, R P; Dimbylow, P J

    2005-01-01

    A change in the posture of the human body can significantly affect the way in which it absorbs radiofrequency electromagnetic radiation. To study this, an anatomically realistic model of the body has been modified to develop new voxel models in postures other than the standard standing position with arms to the side. These postures were sitting, arms stretched out horizontally to the side and vertically above the head. Finite-difference time-domain (FDTD) calculations of the whole-body averaged specific energy absorption rate (SAR) have been performed from 10 MHz to 300 MHz at a resolution of 4 mm. Calculations show that the effect of a raised arm above the head posture was to increase the value of the whole-body averaged SAR at resonance by up to 35% when compared to the standard, arms by the side position. SAR values, both whole-body averaged and localized in the ankle, were used to derive the external electric field values required to produce the SAR basic restrictions of the ICNIRP guidelines. It was found that, in certain postures, external electric field reference levels alone would not provide a conservative estimate of localized SAR exposure and it would be necessary to invoke secondary reference levels on limb currents to provide compliance with restrictions

  6. Effects of posture on FDTD calculations of specific absorption rate in a voxel model of the human body

    Science.gov (United States)

    Findlay, R. P.; Dimbylow, P. J.

    2005-08-01

    A change in the posture of the human body can significantly affect the way in which it absorbs radiofrequency electromagnetic radiation. To study this, an anatomically realistic model of the body has been modified to develop new voxel models in postures other than the standard standing position with arms to the side. These postures were sitting, arms stretched out horizontally to the side and vertically above the head. Finite-difference time-domain (FDTD) calculations of the whole-body averaged specific energy absorption rate (SAR) have been performed from 10 MHz to 300 MHz at a resolution of 4 mm. Calculations show that the effect of a raised arm above the head posture was to increase the value of the whole-body averaged SAR at resonance by up to 35% when compared to the standard, arms by the side position. SAR values, both whole-body averaged and localized in the ankle, were used to derive the external electric field values required to produce the SAR basic restrictions of the ICNIRP guidelines. It was found that, in certain postures, external electric field reference levels alone would not provide a conservative estimate of localized SAR exposure and it would be necessary to invoke secondary reference levels on limb currents to provide compliance with restrictions.

  7. Effects of posture on FDTD calculations of specific absorption rate in a voxel model of the human body

    Energy Technology Data Exchange (ETDEWEB)

    Findlay, R P; Dimbylow, P J [National Radiological Protection Board, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom)

    2005-08-21

    A change in the posture of the human body can significantly affect the way in which it absorbs radiofrequency electromagnetic radiation. To study this, an anatomically realistic model of the body has been modified to develop new voxel models in postures other than the standard standing position with arms to the side. These postures were sitting, arms stretched out horizontally to the side and vertically above the head. Finite-difference time-domain (FDTD) calculations of the whole-body averaged specific energy absorption rate (SAR) have been performed from 10 MHz to 300 MHz at a resolution of 4 mm. Calculations show that the effect of a raised arm above the head posture was to increase the value of the whole-body averaged SAR at resonance by up to 35% when compared to the standard, arms by the side position. SAR values, both whole-body averaged and localized in the ankle, were used to derive the external electric field values required to produce the SAR basic restrictions of the ICNIRP guidelines. It was found that, in certain postures, external electric field reference levels alone would not provide a conservative estimate of localized SAR exposure and it would be necessary to invoke secondary reference levels on limb currents to provide compliance with restrictions.

  8. Energy transmission transformer for a wireless capsule endoscope: analysis of specific absorption rate and current density in biological tissue.

    Science.gov (United States)

    Shiba, Kenji; Nagato, Tomohiro; Tsuji, Toshio; Koshiji, Kohji

    2008-07-01

    This paper reports on the electromagnetic influences on the analysis of biological tissue surrounding a prototype energy transmission system for a wireless capsule endoscope. Specific absorption rate (SAR) and current density were analyzed by electromagnetic simulator in a model consisting of primary coil and a human trunk including the skin, fat, muscle, small intestine, backbone, and blood. First, electric and magnetic strength in the same conditions as the analytical model were measured and compared to the analytical values to confirm the validity of the analysis. Then, SAR and current density as a function of frequency and output power were analyzed. The validity of the analysis was confirmed by comparing the analytical values with the measured ones. The SAR was below the basic restrictions of the International Commission on Nonionizing Radiation Protection (ICNIRP). At the same time, the results for current density show that the influence on biological tissue was lowest in the 300-400 kHz range, indicating that it was possible to transmit energy safely up to 160 mW. In addition, we confirmed that the current density has decreased by reducing the primary coil's current.

  9. Specific absorption rate and electric field measurements in the near field of six mobile phone base station antennas.

    Science.gov (United States)

    Toivonen, Tommi; Toivo, Tim; Puranen, Lauri; Jokela, Kari

    2009-05-01

    In this article, the exposure to radio frequency electromagnetic fields was studied in close proximity (distances of 10, 100, 300, and 600 mm) to six base station antennas. The specific absorption rate (SAR) in 800 mm x 500 mm x 200 mm box phantom as well as unperturbed electric field (E) in air was measured. The results were used to determine whether the measurement of local maximum of unperturbed electric field can be used as a compliance check for local exposure. Also, the conservativeness of this assessment method compared to the ICNIRP basic restriction was studied. Moreover, the assessment of whole-body exposure was discussed and the distance ranges presented in which the ICNIRP limit for local exposure could be exceeded before the limit for whole-body SAR. These results show that the electric field measurement alone can be used for easy compliance check for the local exposure at all distances and for all antenna types studied. However, in some cases when the local peak value of E was compared directly to the ICNIRP reference level for unperturbed E, the exposure was overestimated only very slightly (by factor 1.1) compared to the basic restriction for localized SAR in a human, and hence these results can not be generalized to all antenna types. Moreover, it was shown that the limit for localized exposure could be exceeded before the limit for the whole-body average SAR, if the distance to the antenna was less than 240 mm. Copyright 2009 Wiley-Liss, Inc.

  10. Enzymatic Spectrophotometric Reaction Rate Determination of Glucose in Fruit Drinks and Carbonated Beverages. An Analytical Chemistry Laboratory Experiment for Food Science-Oriented Students

    Science.gov (United States)

    Vasilarou, Argyro-Maria G.; Georgiou, Constantinos A.

    2000-10-01

    The glucose oxidase-horseradish peroxidase coupled reaction using phenol and 4-aminoantipyrine is used for the kinetic determination of glucose in drinks and beverages. This laboratory experiment demonstrates the implementation of reaction rate kinetic methods of analysis, the use of enzymes as selective analytical reagents for the determination of substrates, the kinetic masking of ascorbic acid interference, and the analysis of glucose in drinks and beverages. The method is optimized for student use in the temperature range of 18-28 °C and can be used in low-budget laboratories equipped with an inexpensive visible photometer. The mixed enzyme-chromogen solution that is used is stable for two months. Precision ranged from 5.1 to 12% RSD for analyses conducted during a period of two months by 48 students.

  11. Specific absorption rate variation in a brain phantom due to exposure by a 3G mobile phone: problems in dosimetry.

    Science.gov (United States)

    Behari, J; Nirala, Jay Prakash

    2013-12-01

    A specific absorption rate (SAR) measurements system has been developed for compliance testing of personal mobile phone in a brain phantom material contained in a Perspex box. The volume of the box has been chosen corresponding to the volume of a small rat and illuminated by a 3G mobile phone frequency (1718.5 MHz), and the emitted radiation directed toward brain phantom .The induced fields in the phantom material are measured. Set up to lift the plane carrying the mobile phone is run by a pulley whose motion is controlled by a stepper motor. The platform is made to move at a pre-determined rate of 2 degrees per min limited up to 20 degrees. The measured data for induced fields in various locations are used to compute corresponding SAR values and inter comparison obtained. These data are also compared with those when the mobile phone is placed horizontally with respect to the position of the animal. The SAR data is also experimentally obtained by measuring a rise in temperature due to this mobile exposures and data compared with those obtained in the previous set. To seek a comparison with the safety criteria same set of measurements are performed in 10 g phantom material contained in a cubical box. These results are higher than those obtained with the knowledge of induced field measurements. It is concluded that SAR values are sensitive to the angular position of the moving platform and are well below the safety criteria prescribed for human exposure. The data are suggestive of having a fresh look to understand the mode of electromagnetic field -bio interaction.

  12. Study on the mechanism of human blood glucose concentration measuring using mid-infrared spectral analysis technology

    Science.gov (United States)

    Li, Xiang

    2016-10-01

    All forms of diabetes increase the risk of long-term complications. Blood glucose monitoring is of great importance for controlling diabetes procedure, preventing the complications and improving the patient's life quality. At present, the clinical blood glucose concentration measurement is invasive and could be replaced by noninvasive spectroscopy analytical techniques. The mid-infrared spectral region contains strong characteristic and well-defined absorption bands. Therefore, mid-infrared provides an opportunity for monitoring blood glucose invasively with only a few discrete bonds. Although the blood glucose concentration measurement using mid-infrared spectroscopy has a lot of advantages, the disadvantage is also obvious. The absorption in this infrared region is fundamental molecular group vibration. Absorption intensity is very strong, especially for biological molecules. In this paper, it figures out that the osmosis rate of glucose has a certain relationship with the blood glucose concentration. Therefore, blood glucose concentration could be measured indirectly by measuring the glucose exudate in epidermis layer. Human oral glucose tolerance tests were carried out to verify the correlation of glucose exudation in shallow layer of epidermis layer and blood glucose concentration. As it has been explained above, the mid-infrared spectral region contains well-defined absorption bands, the intensity of absorption peak around 1123 cm-1 was selected to measure the glucose and that around 1170 cm-1 was selected as reference. Ratio of absorption peak intensity was recorded for each set of measurement. The effect and importance of the cleaning the finger to be measured before spectrum measuring are discussed and also verified by experiment.

  13. Abnormal transient rise in hepatic glucose production after oral glucose in non-insulin-dependent diabetic subjects.

    Science.gov (United States)

    Thorburn, A; Litchfield, A; Fabris, S; Proietto, J

    1995-05-01

    A transient rise in hepatic glucose production (HGP) after an oral glucosa load has been reported in some insulin-resistant states such as in obese fa/fa Zucker rats. The aim of this study was to determine whether this rise in HGP also occurs in subjects with established non-insulin-dependent diabetes mellitus (NIDDM). Glucose kinetics were measured basally and during a double-label oral glucose tolerance test (OGTT) in 12 NIDDM subjects and 12 non-diabetic 'control' subjects. Twenty minutes after the glucose load, HGP had increased 73% above basal in the NIDDM subjects (7.29 +/- 0.52 to 12.58 +/- 1.86 mumol/kg/min, P < 0.02). A transient rise in glucagon (12 pg/ml above basal, P < 0.004) occurred at a similar time. In contrast, the control subjects showed no rise in HGP or plasma glucagon. HGP began to suppress 40-50 min after the OGTT in both the NIDDM and control subjects. A 27% increase in the rate of gut-derived glucose absorption was also observed in the NIDDM group, which could be the result of increased gut glucose absorption or decreased first pass extraction of glucose by the liver. Therefore, in agreement with data in animal models of NIDDM, a transient rise in HGP partly contributes to the hyperglycemia observed after an oral glucose load in NIDDM subjects.

  14. Effect of gestational age and blood glucose on C-peptide excretion rate and clearance in neonates.

    Science.gov (United States)

    Salis, Emma R; Soelbeck, Mikkel K; Reith, David M; Wheeler, Benjamin J; Broadbent, Roland S; Medlicott, Natalie J

    2016-01-01

    The aim of this study was to measure urinary C-peptide concentrations, and then calculate C-peptide clearance (Cl), and excretion rate (UER) in neonates. In addition, the effect of gestational age (GA) and blood glucose levels (BGL) on C-peptide UER were investigated. Insulin concentrations in plasma and C-peptide concentrations were measured in plasma and urine, in 20 neonates. Chemiluminescent immunoassays were used for insulin and C-peptide measurements, with urine diluted to 40% with bovine serum albumin 1% in phosphate buffered saline. Urine volume and time of collection were recorded and used to calculate UER and Cl. The mean Cl of C-peptide was 0.309 ± 0.329 mL/min/kg, and UER was 0.0329 ± 0.0342 pmol/min/kg. Correlations between Cl or UER and GA were not significant (P > 0.05). No significant correlation was shown between Cl or UER and BGL (P > 0.05). Both Cl and UER were highly variable in neonates, but were not correlated with GA. Additionally, BGL did not appear to affect C-peptide UER and Cl. As GA and BGL did not appear to affect Cl and UER, urinary C-peptide may provide a non-invasive method of measuring insulin production in neonates. © 2015 The Authors. Journal of Paediatrics and Child Health © 2015 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  15. [Estimated glucose disposal rate in patients under 18 years of age with type 1 diabetes mellitus and overweight or obesity].

    Science.gov (United States)

    Palomo Atance, Enrique; Ballester Herrera, M José; Giralt Muiña, Patricio; Ruiz Cano, Rafael; León Martín, Alberto; Giralt Muiña, Juan

    2013-01-01

    To assess the estimated glucose disposal rate (eGDR), insulin dose, and lipoprotein profile in children with type 1 diabetes mellitus (T1DM) and overweight or obesity as compared to children with T1DM and normal weight. A total of 115 patients (aged 5-16 years) with T1DM on intensive insulin therapy were recruited. The following parameters were measured: weight, height, body mass index, waist and hip circumference, insulin dose, eGDR, glycosylated hemoglobin, blood pressure, and lipoprotein profile. Results were stratified by sex and age. No significant differences were found in eGDR between children with normal weight, overweight, and obesity. However, obese children older than 11 years had lower eGDR values (9.3±1.3 vs 10.1±0.8 mg kg(-1)min(-1); p<0.01). Insulin dose was higher in overweight and obese children, especially in IU/m2/day (37.7 vs 36.1 vs. 29.4 respectively; p<0.01). Obese children had higher low-density lipoprotein cholesterol levels than children with overweight and normal weight (106.5 vs 91.7 vs 91.5mg/dL respectively; p<0.01). No correlation was found between waist circumference and the different markers of insulin resistance. Values of eGDR values were lower in obese children with T1DM older than 11 years, and this may therefore be considered a marker of insulin resistance. Insulin dose was higher in diabetic patients with overweight or obesity, specially in IU/m2/day. Obese children with T1DM had a lipoprotein profile of cardiovascular risk. Copyright © 2012 SEEN. Published by Elsevier Espana. All rights reserved.

  16. Impact of concentration and rate of intraluminal drug delivery on absorption and gut wall metabolism of verapamil in humans.

    Science.gov (United States)

    Glaeser, Hartmut; Drescher, Siegfried; Hofmann, Ute; Heinkele, Georg; Somogyi, Andrew A; Eichelbaum, Michel; Fromm, Martin F

    2004-09-01

    In humans gut wall metabolism can be quantitatively as important as hepatic drug metabolism in limiting the systemic exposure to drugs after oral administration. However, it has been proposed that the role of gut wall metabolism might be overemphasized, because high luminal drug concentrations would lead to a saturation of gut wall metabolism. Therefore we investigated the impact of concentration and rate of intraluminal drug delivery on absorption (F(abs)) and gastrointestinal extraction (E(GI)) of a luminally administered cytochrome P450 (CYP) 3A4 substrate (verapamil) using a multilumen perfusion catheter in combination with a stable isotope technique. Two 20-cm-long, adjacent jejunal segments were isolated with the multilumen perfusion catheter in 7 subjects. In this study 80 mg of unlabeled verapamil (d0-verapamil 15 min) was infused into one segment over a 15-minute period, 80 mg of 3-fold deuterated verapamil (d3-verapamil 240 min) was administered over a 240-minute period into the other segment, and simultaneously, 5 mg of 7-fold deuterated verapamil (d7-verapamil) was injected intravenously over a 15-minute period. The rate of intraluminal drug delivery had only a modest effect on bioavailability of the verapamil isotopes (after correction for F abs ) (F/F abs d3-verapamil 240 min versus d0-verapamil 15 min, 0.24 +/- 0.10 versus 0.20 +/- 0.09; P d3-verapamil 240 min was 0.50 +/- 0.18 compared with 0.59 +/- 0.14 for d0 -verapamil 15 min ( P d0-verapamil 15 min ) correlated strongly with E GI (d3-verapamil 240 min ) (r = 0.94, P d0-verapamil 15 min /d3-verapamil 240 min (r = 0.62, P =.03). Substantial gut wall metabolism of verapamil occurs in humans and can be predicted from ex vivo data by use of shed enterocytes. The different intraluminal concentrations and rates of intraluminal drug delivery did not lead to a pronounced saturation of intestinal drug metabolism.

  17. Exenatide Regulates Cerebral Glucose Metabolism in Brain Areas Associated With Glucose Homeostasis and Reward System.

    Science.gov (United States)

    Daniele, Giuseppe; Iozzo, Patricia; Molina-Carrion, Marjorie; Lancaster, Jack; Ciociaro, Demetrio; Cersosimo, Eugenio; Tripathy, Devjit; Triplitt, Curtis; Fox, Peter; Musi, Nicolas; DeFronzo, Ralph; Gastaldelli, Amalia

    2015-10-01

    Glucagon-like peptide 1 receptors (GLP-1Rs) have been found in the brain, but whether GLP-1R agonists (GLP-1RAs) influence brain glucose metabolism is currently unknown. The study aim was to evaluate the effects of a single injection of the GLP-1RA exenatide on cerebral and peripheral glucose metabolism in response to a glucose load. In 15 male subjects with HbA1c of 5.7 ± 0.1%, fasting glucose of 114 ± 3 mg/dL, and 2-h glucose of 177 ± 11 mg/dL, exenatide (5 μg) or placebo was injected in double-blind, randomized fashion subcutaneously 30 min before an oral glucose tolerance test (OGTT). The cerebral glucose metabolic rate (CMRglu) was measured by positron emission tomography after an injection of [(18)F]2-fluoro-2-deoxy-d-glucose before the OGTT, and the rate of glucose absorption (RaO) and disposal was assessed using stable isotope tracers. Exenatide reduced RaO0-60 min (4.6 ± 1.4 vs. 13.1 ± 1.7 μmol/min ⋅ kg) and decreased the rise in mean glucose0-60 min (107 ± 6 vs. 138 ± 8 mg/dL) and insulin0-60 min (17.3 ± 3.1 vs. 24.7 ± 3.8 mU/L). Exenatide increased CMRglu in areas of the brain related to glucose homeostasis, appetite, and food reward, despite lower plasma insulin concentrations, but reduced glucose uptake in the hypothalamus. Decreased RaO0-60 min after exenatide was inversely correlated to CMRglu. In conclusion, these results demonstrate, for the first time in man, a major effect of a GLP-1RA on regulation of brain glucose metabolism in the absorptive state. © 2015 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.

  18. Localized specific absorption rate calculations in a realistic phantom leg at 1-30 MHz using a finite element method

    International Nuclear Information System (INIS)

    Wainwright, P.R.

    1999-01-01

    Protection standards for radiofrequency electromagnetic radiation are principally intended to avoid detrimental thermal effects. To this end the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and national bodies such as the National Radiological Protection Board (NRPB), recommend limitations on the localized specific energy absorption rate (SAR) in various parts of the body. The role of numerical dosimetry is to estimate the SAR from measurable parameters such as external field strengths and total body currents. In recent years there have been significant advances in the sophistication of the anatomical models available, and in our knowledge of the electrical properties of the body tissues. Several groups, including NRPB, have developed mathematical phantoms from medical imaging data, such as MRI scans. It has been known for some time that under certain circumstances SAR restrictions may be violated in the ankle due to the concentration of current in a small area. In this paper the author presents calculations of the SAR distribution in a human leg in the high-frequency (HF) band. This band contains the human whole-body resonance frequency and therefore gives the strongest coupling of the body to the field. The present study uses a finite element model with variable mesh size, derived from a 2 mm resolution voxel phantom of the whole body. It also uses recently acquired data on the electrical properties of the tissues. The results are discussed in the light of the exposure standards promulgated by national and international bodies such as NRPB and ICNIRP, and it is shown that the basic SAR restrictions in the leg are ensured by a current reference level of 100 mA. (author)

  19. Uncertainties in the estimation of specific absorption rate during radiofrequency alternating magnetic field induced non-adiabatic heating of ferrofluids

    Science.gov (United States)

    Lahiri, B. B.; Ranoo, Surojit; Philip, John

    2017-11-01

    Magnetic fluid hyperthermia (MFH) is becoming a viable cancer treatment methodology where the alternating magnetic field induced heating of magnetic fluid is utilized for ablating the cancerous cells or making them more susceptible to the conventional treatments. The heating efficiency in MFH is quantified in terms of specific absorption rate (SAR), which is defined as the heating power generated per unit mass. In majority of the experimental studies, SAR is evaluated from the temperature rise curves, obtained under non-adiabatic experimental conditions, which is prone to various thermodynamic uncertainties. A proper understanding of the experimental uncertainties and its remedies is a prerequisite for obtaining accurate and reproducible SAR. Here, we study the thermodynamic uncertainties associated with peripheral heating, delayed heating, heat loss from the sample and spatial variation in the temperature profile within the sample. Using first order approximations, an adiabatic reconstruction protocol for the measured temperature rise curves is developed for SAR estimation, which is found to be in good agreement with those obtained from the computationally intense slope corrected method. Our experimental findings clearly show that the peripheral and delayed heating are due to radiation heat transfer from the heating coils and slower response time of the sensor, respectively. Our results suggest that the peripheral heating is linearly proportional to the sample area to volume ratio and coil temperature. It is also observed that peripheral heating decreases in presence of a non-magnetic insulating shielding. The delayed heating is found to contribute up to ~25% uncertainties in SAR values. As the SAR values are very sensitive to the initial slope determination method, explicit mention of the range of linear regression analysis is appropriate to reproduce the results. The effect of sample volume to area ratio on linear heat loss rate is systematically studied and the

  20. Uncertainties in the estimation of specific absorption rate during radiofrequency alternating magnetic field induced non-adiabatic heating of ferrofluids

    International Nuclear Information System (INIS)

    Lahiri, B B; Ranoo, Surojit; Philip, John

    2017-01-01

    Magnetic fluid hyperthermia (MFH) is becoming a viable cancer treatment methodology where the alternating magnetic field induced heating of magnetic fluid is utilized for ablating the cancerous cells or making them more susceptible to the conventional treatments. The heating efficiency in MFH is quantified in terms of specific absorption rate (SAR), which is defined as the heating power generated per unit mass. In majority of the experimental studies, SAR is evaluated from the temperature rise curves, obtained under non-adiabatic experimental conditions, which is prone to various thermodynamic uncertainties. A proper understanding of the experimental uncertainties and its remedies is a prerequisite for obtaining accurate and reproducible SAR. Here, we study the thermodynamic uncertainties associated with peripheral heating, delayed heating, heat loss from the sample and spatial variation in the temperature profile within the sample. Using first order approximations, an adiabatic reconstruction protocol for the measured temperature rise curves is developed for SAR estimation, which is found to be in good agreement with those obtained from the computationally intense slope corrected method. Our experimental findings clearly show that the peripheral and delayed heating are due to radiation heat transfer from the heating coils and slower response time of the sensor, respectively. Our results suggest that the peripheral heating is linearly proportional to the sample area to volume ratio and coil temperature. It is also observed that peripheral heating decreases in presence of a non-magnetic insulating shielding. The delayed heating is found to contribute up to ∼25% uncertainties in SAR values. As the SAR values are very sensitive to the initial slope determination method, explicit mention of the range of linear regression analysis is appropriate to reproduce the results. The effect of sample volume to area ratio on linear heat loss rate is systematically studied and

  1. Effects of β-hydroxy β-methyl butyrate supplementation to sows in late gestation on absorption and hepatic metabolism of glucose and amino acids during transition

    DEFF Research Database (Denmark)

    Flummer, Christine; Lyby, H; Storli, K S

    2012-01-01

    A multicatheter sow model was established to study the effects of dietary β-hydroxy β-methyl butyrate (HMB) supplementation on net portal flux (NPF) and net hepatic flux (NHF) of HMB, glucose, and the AA Ala, Gly, Ile, Leu, Phe, Tyr, and Val. Eight second parity sows were fitted with permanent...... the experiment, and 4 HMB sows were fed the control diet supplemented with 15 mg Ca(HMB)2/kg BW mixed in one third of the morning meal from day –10 until parturition. Net portal flux of HMB was affected by treatment (Trt; P HMB sows at 6.9 mmol/h 30 min after the morning meal...... and then decreased towards preprandial level (0.0 mmol/h) 3.5 h after the meal, revealing that dietary HMB was rapidly absorbed from the intestine. The NHF of HMB tended to be affected by Trt (P = 0.06) showing a small hepatic uptake of HMB (1.1 mmol/h) in HMB sows. Net portal flux of glucose and all measured AA...

  2. Effect of absorbable and nonabsorbable sugars on intestinal calcium absorption in humans

    International Nuclear Information System (INIS)

    Griessen, M.; Speich, P.V.; Infante, F.; Bartholdi, P.; Cochet, B.; Donath, A.; Courvoisier, B.; Bonjour, J.P.

    1989-01-01

    The effects of glucose, galactose, and lactitol on intestinal calcium absorption and gastric emptying were studied in 9, 8, and 20 healthy subjects, respectively. Calcium absorption was measured by using a double-isotope technique and the kinetic parameters were obtained by a deconvolution method. The gastric emptying rate was determined with /sup 99m/Tc-diethylenetriaminepentaacetic acid and was expressed as the half-time of the emptying curve. Each subject was studied under two conditions: (a) with calcium alone and (b) with calcium plus sugar. Glucose and galactose increased the calcium mean transit time and improved the total fractional calcium absorption by 30% (p less than 0.02). Lactitol decreased the mean rate of absorption (p less than 0.001) and reduced the total fractional calcium absorption by 15% (p less than 0.001). The gastric emptying rate did not appear to influence directly the kinetic parameters of calcium absorption. These results show that both glucose and galactose exert the same stimulatory effect as lactose on calcium absorption in subjects with normal lactase whereas lactitol mimics the effects of lactose in lactase-deficient patients. Thus the absorbability of sugars determines their effect on calcium absorption

  3. The rate of cerebral utilization of glucose, ketone bodies, and oxygen: a comparative in vivo study of infant and adult rats.

    Science.gov (United States)

    Dahlquist, G; Persson, B

    1976-11-01

    Cerebral blood flow (CBF) was measured by means of Celabeled microspheres in infant (20-day-old) and adult (3-month-old) rats, anesthetised with Na-5-ethyl-5-(1-methylpropyl)2-thiobarbituric acid. Cerebral arteriovenous differences of acetoacetate, D-beta-hydroxybutyrate, glucose, lactate, and oxygen and brain DNA content were determined in other groups of similarly treated infant and adult animals fed or starved for 48 or 72 hr. The mean CBF values of 0.48+/-0.04 and 0.62+/-0.07 ml/(g X min), +/- SEM, in infant and adult animals, respectively, were not significantly different. CBF was unaffected by starvation. At any given arterial concentration the cerebral arteriovenous difference of acetoacetate was significantly higher in infant than adult rats. The same was true for D-beta-hydroxybutyrate at arterial concentrations above 1 mmol/liter. There was an approximately linear relationship between arterial concentration of acetoacetate and its cerebral arteriovenous difference in both infant and adult rats. A similar relationship was found for D-beta-hydroxybutyrate only in infant animals. In the fed state, the cerebral uptake of glucose and ketone bodies (micromoles per (mg DNA X min)) was not different in infant and adult rats. During starvation, cerebral uptake of ketone bodies expressed as micromoles per (mg DNA X min) was higher in infant than adult rats, indicating a higher rate of utilization of ketone bodies per cell in these animals. For glucose, no such difference was found in either fed or starved groups (Table 3). The average percentage of the total cerebral uptake of substrates (micromoles per min) accounted for by ketone bodies increased in both infant and adult rats during starvation. This percentage value was clearly higher in infant than adult rats during starvation. After 72 hr of starvation the values were 38.8% and 15.2% in infant and adult rats, respectively (Fig. 3). Calculated cerebral metabolic rate for oxygen (CMRO2), assuming complete

  4. Estimation of gluconeogenesis and glucose utilization in carbohydate deficient growing rats

    International Nuclear Information System (INIS)

    Hill, F.W.; Egtesadi, S.; Rucker, R.B.

    1986-01-01

    A carbohydrate deficient diet based on food grade oleic acid and soybean oil and a minimally adequate level of casein protein was supplemented with graded levels of glucose (0, 4, 10, 65%), and casein protein (12% basal level plus 4, 6, 20%). Weanling rats were fed the respective diets for 28 days. Under anesthesia in fed state, the right jugular vein and left carotid artery were cannulated. NaH 14 CO 3 and 3 H-glucose labelled on C 6 were injected into aorta via carotid and blood samples taken from vena cava via jugular over a period of 30 minutes. Rate of increase of blood 14 C-glucose was the indicator of gluconeogenesis (GLNG). Disappearance of blood 3 H-glucose was the measure of glucose flux. Relative rate of GLNG was very high in basal unsupplemented rats, and glucose flux was very low. Rats growing rapidly with minimum supplementation (4% glucose or 6% casein) showed the lowest relative rate of GLNG and maximum glucose flux, of the order of 10 mg min -1 kg -1 . GLNG increased with higher levels of glucose and casein, but flux did not increase. The fed state glucose flux extrapolated to 24 hour basis was approximately 2X greater than the dietary intake of glucose and its equivalent of glucogenic precursors in rats fed the basal diet and low levels of supplements. Adjustment for lower flux in post absorptive state, based on flux in fasted rats, reduced the differences between observed flux and intake

  5. Quantitative assessment of cerebral glucose metabolic rates after blood-brain barrier disruption induced by focused ultrasound using FDG-MicroPET.

    Science.gov (United States)

    Yang, Feng-Yi; Chang, Wen-Yuan; Chen, Jyh-Cheng; Lee, Lin-Chien; Hung, Yi-Shun

    2014-04-15

    The goal of this study was to evaluate the pharmacokinetics of (18)F-2-fluoro-2-deoxy-d-glucose ((18)F-FDG) and the expression of glucose transporter 1 (GLUT1) protein after blood-brain barrier (BBB) disruption of normal rat brains by focused ultrasound (FUS). After delivery of an intravenous bolus of ~37 MBq (1 mCi) (18)F-FDG, dynamic positron emission tomography scans were performed on rats with normal brains and those whose BBBs had been disrupted by FUS. Arterial blood sampling was collected throughout the scanning procedure. A 2-tissue compartmental model was used to estimate (18)F-FDG kinetic parameters in brain tissues. The rate constants Ki, K1, and k3 were assumed to characterize the uptake, transport, and hexokinase activity, respectively, of (18)F-FDG. The uptake of (18)F-FDG in brains significantly decreased immediately after the blood-brain barrier was disrupted. At the same time, the derived values of Ki, K1, and k3 for the sonicated brains were significantly lower than those for the control brains. In agreement with the reduction in glucose, Western blot analyses confirmed that focused ultrasound exposure significantly reduced the expression of GLUT1 protein in the brains. Furthermore, the effect of focused ultrasound on glucose uptake was transient and reversible 24h after sonication. Our results indicate that focused ultrasound may inhibit GLUT1 expression to decrease the glucose uptake in brain tissue during the period of BBB disruption. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. The Effect of Acute Consumption of Energy Drinks on Blood Pressure, Heart Rate and Blood Glucose in the Group of Young Adults

    Directory of Open Access Journals (Sweden)

    Dariusz Nowak

    2018-03-01

    Full Text Available Background: Energy drinks (EDs are very popular among young people, who consume them for various reasons. A standard ED typically contains 80 mg of caffeine, as well as glucose, taurine, vitamins and other ingredients. Excessive consumption of EDs and accumulation of the above ingredients, as well as their mutual interactions, can be hazardous to the health of young adults. The purpose of this study was to assess the effect of acute consumption of energy drinks on blood pressure, heart rate and blood glucose. Methods: The study involved 68 volunteers, healthy young adults (mean age 25 years, who were divided into two groups: the first consumed three EDs at one-hour intervals, and the second drank the same amount of water. All participants had their blood pressure (BP—systolic and diastolic (SBP and DBP—as well as heart rate (HR and blood glucose (BG measured. In addition, participants could report any health problems before and after consuming each portion of ED. Results: In the above experiment, having consumed three portions of ED (240 mg of caffeine, the participants presented a significant increase in DBP (p = 0.003, by over 8%, which coincided with a lack of any significant impact on SBP (p = 0.809. No significant changes were noted in HR (p = 0.750. Consumption of EDs caused a significant increase (p < 0.001 in BG, by ca. 21%, on average. Some participants reported various discomforts, which escalated after 2 and 3 EDs. Conclusions: Acute consumption of EDs contributed to increased diastolic blood pressure, blood glucose and level of discomfort in healthy young people. Our results reinforce the need for further studies on a larger population to provide sufficient evidence.

  7. Optical absorption of irradiated carbohydrates

    International Nuclear Information System (INIS)

    Supe, A.A.; Tiliks, Yu.E.

    1994-01-01

    The optical absorption spectra of γ-irradiated carbohydrates (glucose, lactose, sucrose, maltose, and starch) and their aqueous solutions were studied. The comparison of the data obtained with the determination of the concentrations of molecular and radical products of radiolysis allows the absorption bands with maxima at 250 and 310 nm to be assigned to the radicals trapped in the irradiated carbohydrates

  8. Effect of fibre additions to flatbread flour mixes on glucose kinetics: a randomised controlled trial.

    Science.gov (United States)

    Boers, Hanny M; van Dijk, Theo H; Hiemstra, Harry; Hoogenraad, Anne-Roos; Mela, David J; Peters, Harry P F; Vonk, Roel J; Priebe, Marion G

    2017-11-01

    We previously found that guar gum (GG) and chickpea flour (CPF) added to flatbread wheat flour lowered postprandial blood glucose (PPG) and insulin responses dose dependently. However, rates of glucose influx cannot be determined from PPG, which integrates rates of influx, tissue disposal and hepatic glucose production. The objective was to quantify rates of glucose influx and related fluxes as contributors to changes in PPG with GG and CPF additions to wheat-based flatbreads. In a randomised cross-over design, twelve healthy males consumed each of three different 13C-enriched meals: control flatbreads (C), or C incorporating 15 % CPF with either 2 % (GG2) or 4 % (GG4) GG. A dual isotope technique was used to determine the time to reach 50 % absorption of exogenous glucose (T 50 %abs, primary objective), rate of appearance of exogenous glucose (RaE), rate of appearance of total glucose (RaT), endogenous glucose production (EGP) and rate of disappearance of total glucose (RdT). Additional exploratory outcomes included PPG, insulin, glucose-dependent insulinotropic peptide and glucagon-like peptide 1, which were additionally measured over 4 h. Compared with C, GG2 and GG4 had no significant effect on T 50 %abs. However, GG4 significantly reduced 4-h AUC values for RaE, RaT, RdT and EGP, by 11, 14, 14 and 64 %, respectively, whereas GG2 showed minor effects. Effect sizes over 2 and 4 h were similar except for significantly greater reduction in EGP for GG4 at 2 h. In conclusion, a soluble fibre mix added to flatbreads only slightly reduced rates of glucose influx, but more substantially affected rates of postprandial disposal and hepatic glucose production.

  9. Factors influencing [F-18]2-fluoro-2-deoxy-D-glucose (F-18 FDG) uptake in melanoma cells. The role of proliferation rate, viability, glucose transporter expression and hexokinase activity

    International Nuclear Information System (INIS)

    Yamada, Kiyoshi; Brink, I.; Bisse, E.; Epting, T.; Engelhardt, R.

    2005-01-01

    Using human (SK-MEL 23, SK-MEL 24 and G361) and murine (B16) melanoma cell lines, the coregulatory potential of the uptake of the positron emission tomography (PET) tracer, [Fluorine-18]2-fluoro-2-deoxy-D-glucose (F-18 FDG) has been investigated in relationship to tumor characteristics. Comparative studies among the four melanoma cell lines demonstrated that the lowest FDG uptake in SK-MEL 24 corresponded strongly to the data for DT (population doubling time) and MTT (tetrazolium salt) cell viability as well as hexokinase (HK) activity, but was not related to the glucose transporter 1 (GLUT 1) expression level. Furthermore, the FDG uptake in each melanoma cell line measured by cell cycle kinetics was significantly positively correlated to both the proliferation index (PI=S/G 2 M phase fractions) and the cell viability, though with one exception relating to the proliferation index (PI) of the lowest FDG uptake cell line, SK-MEL 24. No positive correlation was found between the expression of GLUT 1 and FDG uptake in any individual cell line. However, the HK activities in SK-MEL 23 and 24 showed considerable positive relationships with FDG uptake. Our present study suggests that both the proliferation rate and the cell viability of melanoma cells may be key factors for FDG uptake and that HK activity, rather than GLUT 1 expression, seems to be a major factor. (author)

  10. Measurement of regional cerebral metabolic rate for glucose in the human subject with (F-18)-2-deoxy-2-fluoro-d-glucose and emission computed tomography: validation of the method

    International Nuclear Information System (INIS)

    Phelps, M.E.; Huang, S.C.; Hoffman, E.J.; Selin, C.; Kuhl, D.E.

    1977-01-01

    Tracer techniques and models of in vitro quantitative autoradiography and tissue counting for the measure of regional metabolic rates (rMR) are combined with emission computed tomography (ECT). This approach, Physiologic Tomography (PT), provides atraumatic and analytical measurements of rMR. PT is exemplified with the regional measurement of the cerebral metabolic rate for glucose (CMRGlu) in man with ( 18 F)-2-deoxy-2-fluoro-D-glucose (FDG) and positron ECT. Our model incorporates a k 4 * mediated hydrolysis of FDG-6-PO 4 to FDG which then competes with phosphorylation (k 3 *) of FDG back to FDG-6-PO 4 and reverse transport (k 2 *) back to blood. Although small, k 4 * is found to be significant. The ECAT positron tomograph was used to measure the rate constants (k 1 *→k 4 *), lumped constant (LC), stability, and reproducibility of the model in man. Since these parameters have not been measured for FDG in any species, comparisons are made to values for DG in rat and monkey. Compartmental concentrations of FDG and FDG-6-PO 4 were determined and show that cerebral FDG-6-PO 4 steadily accumulates for about 100 mins, plateaus and then slowly decreases due to hydrolysis. Cerebral blood FDG concentration was determined to be a minor contribution to tissue activity after 10 min. Regional CMRGlu measurements are reproducible to +- 5.5% over 5 hrs. PT allows the in vivo study ofregional biochemistry and physiology in normal and pathophysiologic states in man with a unique and fundamental capability

  11. Addition of sodium bicarbonate to either 1 or 2 feedings of colostrum replacer: effect on uptake and rate of absorption of immunoglobulin G in neonatal calves.

    Science.gov (United States)

    Cabral, R G; Kent, E J; Haines, D M; Erickson, P S

    2012-06-01

    Forty Holstein dairy calves were blocked by birth date and sex, and randomly assigned to 1 of 4 treatments within each block to elucidate the effect of feeding regimen and sodium bicarbonate (NaHCO₃) supplementation on absorption of IgG from colostrum replacer (CR). Calves received CR containing 191.4 g of IgG fed either in 1 feeding at 0 h (within 45 min of birth), with or without 30 g of NaHCO₃, or in 2 feedings (127.6 g of IgG at 0 h, with or without 20 g of NaHCO₃, and 63.8 g of IgG at 6 h, with or without 10 g of NaHCO₃). The treatments were (1) 1 feeding of CR+0 g of NaHCO₃; (2) 1 feeding of CR+30 g of NaHCO₃; (3) 2 feedings of CR+0 g of NaHCO₃; and (4) 2 feedings of CR+30 g total of NaHCO₃. Only calves born with no dystocia were used on this study. Blood samples were taken at 0, 6, 12, 18, and 24h postpartum and were analyzed for IgG using a radial immunoassay. Results indicated that, individually, feeding regimen and NaHCO₃ treatments had no effect. However, the interaction was significant for 24-h IgG and area under the curve, and showed a trend for apparent efficiency of absorption. Absorption rate data indicated that, for calves fed within 45 min of birth, most IgG absorption occurred in the first 6 h after birth. From 6 to 12 h postpartum, IgG absorption started to decrease; however, IgG absorption remained higher for calves fed in a single feeding than in 2 feedings. These data indicated that NaHCO₃ may increase IgG absorption when calves are fed colostrum in a single feeding but is not beneficial when colostrum is fed in 2 feedings. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  12. Glucose turnover, oxidation, and indices of recycling in severely traumatized patients

    International Nuclear Information System (INIS)

    Jeevanandam, M.; Young, D.H.; Schiller, W.R.

    1990-01-01

    Hyperglycemia is often seen in trauma patients and its etiology is not clearly understood. We have determined parameters of glucose metabolism by using simultaneous primed-constant intravenous infusion of both [6-3H] glucose and [U-14C] glucose in ten severely traumatized hypermetabolic subjects during the early flow phase of injury and in six post-absorptive normal volunteers. The mean rate of glucose production (determined by means of [6-3H] glucose) was 3.96 +/- 0.40 mg/kg/min in trauma patients, which was significantly (p = 0.025) higher than the value of 2.75 +/- 0.13 observed in normal volunteers. Glucose turnover rates determined with [U-14C] glucose as tracer were lower in all subjects. The difference between the turnover rates determined by the two tracers represents an index of recycling of glucose through three-carbon fragments. This recycling index was similar in both groups of subjects in amount (0.24 +/- 0.07 vs. 0.26 +/- 0.08 mg glucose/kg/min) but different when expressed as percentage of total glucose turnover (5.6 +/- 1.4% vs. 9.8 +/- 1.7%; p = 0.05). The absolute rates of glucose clearance, oxidation, and recycling were similar in stressed trauma patients and unstressed controls although the rate of production was increased by 44% due to injury. Post-trauma hyperglycemia was mainly due to an increased hepatic output of glucose and not due to a decreased ability of the tissue to extract glucose from the plasma. Hyperglycemia may be the driving force in the metabolic effects of injury

  13. Glucose turnover, oxidation, and indices of recycling in severely traumatized patients

    Energy Technology Data Exchange (ETDEWEB)

    Jeevanandam, M.; Young, D.H.; Schiller, W.R. (St. Joseph' s Hospital Medical Center, Phoenix, AZ (USA))

    1990-05-01

    Hyperglycemia is often seen in trauma patients and its etiology is not clearly understood. We have determined parameters of glucose metabolism by using simultaneous primed-constant intravenous infusion of both (6-3H) glucose and (U-14C) glucose in ten severely traumatized hypermetabolic subjects during the early flow phase of injury and in six post-absorptive normal volunteers. The mean rate of glucose production (determined by means of (6-3H) glucose) was 3.96 +/- 0.40 mg/kg/min in trauma patients, which was significantly (p = 0.025) higher than the value of 2.75 +/- 0.13 observed in normal volunteers. Glucose turnover rates determined with (U-14C) glucose as tracer were lower in all subjects. The difference between the turnover rates determined by the two tracers represents an index of recycling of glucose through three-carbon fragments. This recycling index was similar in both groups of subjects in amount (0.24 +/- 0.07 vs. 0.26 +/- 0.08 mg glucose/kg/min) but different when expressed as percentage of total glucose turnover (5.6 +/- 1.4% vs. 9.8 +/- 1.7%; p = 0.05). The absolute rates of glucose clearance, oxidation, and recycling were similar in stressed trauma patients and unstressed controls although the rate of production was increased by 44% due to injury. Post-trauma hyperglycemia was mainly due to an increased hepatic output of glucose and not due to a decreased ability of the tissue to extract glucose from the plasma. Hyperglycemia may be the driving force in the metabolic effects of injury.

  14. In vitro degradation of pure Mg in response to glucose

    Science.gov (United States)

    Zeng, Rong-Chang; Li, Xiao-Ting; Li, Shuo-Qi; Zhang, Fen; Han, En-Hou

    2015-08-01

    Magnesium and its alloys are promising biodegradable biomaterials but are still challenging to be used in person with high levels of blood glucose or diabetes. To date, the influence of glucose on magnesium degradation has not yet been elucidated, this issue requires more attention. Herein, we present pure Mg exhibiting different corrosion responses to saline and Hank’s solutions with different glucose contents, and the degradation mechanism of pure Mg in the saline solution with glucose in comparison with mannitol as a control. On one hand, the corrosion rate of pure Mg increases with the glucose concentration in saline solutions. Glucose rapidly transforms into gluconic acid, which attacks the oxides of the metal and decreases the pH of the solution; it also promotes the absorption of chloride ions on the Mg surface and consequently accelerates corrosion. On the other hand, better corrosion resistance is obtained with increasing glucose content in Hank’s solution due to the fact that glucose coordinates Ca2+ ions in Hank’s solution and thus improves the formation of Ca-P compounds on the pure Mg surface. This finding will open up new avenues for research on the biodegradation of bio-Mg materials in general, which could yield many new and interesting results.

  15. Glucose and insulin dynamics associated with continuous rate infusion of dextrose solution or dextrose solution and insulin in healthy and endotoxin-exposed horses.

    Science.gov (United States)

    Han, Janet H; McKenzie, Harold C; McCutcheon, L Jill; Geor, Raymond J

    2011-04-01

    To investigate the effects of a continuous rate infusion (CRI) of dextrose solution or dextrose solution and insulin on glucose and insulin concentrations in healthy and endotoxin-exposed horses. 9 adult mares. During phase 1, treatments consisted of saline (0.9% NaCl) solution (control group; n = 4) or 20% dextrose solution (group 1; 4) administered IV as a 360-minute CRI. During phase 2, treatments consisted of 360-minute CRIs of 20% dextrose solution and insulin administered simultaneously at 367.6 mg/kg/h (30 kcal/kg/d) and 0.07 U/kg/h, respectively, in healthy horses (group 2; n = 4) or horses administered 35 ng of lipopolysaccharide/kg, IV, 24 hours before starting the dextrose solution and insulin CRIs (group 3; 4). A balanced crossover study design was used in both phases. Blood samples were collected for measurement of plasma glucose and insulin concentrations. Infusion of dextrose solution alone resulted in hyperglycemia for most of the 360-minute CRI. Insulin concentration increased significantly in group 1, compared with that in the control group. Mean insulin concentration of group 2 was significantly higher throughout most of the infusion period, compared with concentrations of the control group and group 1. Mean glucose concentration did not differ significantly between groups 2 and 3. Insulin infusion at a rate of 0.07 U/kg/h was found to be effective for the prevention of hyperglycemia when administered concurrently with dextrose solution. This rate was considered to be safe because horses did not become hypoglycemic during infusions of dextrose solution.

  16. A randomized cross-over study of the acute effects of running 5 km on glucose, insulin, metabolic rate, cortisol and Troponin T

    OpenAIRE

    Keselman, Boris; Vergara, Marta; Nyberg, Sofia; Nystrom, Fredrik H.

    2017-01-01

    Background We aimed to study the impact by running 5 km, at maximal speed, on the normal variations of metabolic variables related to glucose, insulin, insulin sensitivity, cortisol, glucagon, Troponin T and metabolic rate. Material and methods Five women and 12 men 25.7 +/- 5.2 years of age with a body-mass-index of 22.5 +/- 2.3 kg/m(2) where recruited to run 5 km at individual maximal speed in the morning, and to a corresponding day of rest, followed by standardized breakfast and lunch meal...

  17. EFSA Panel on Dietetic Products, Nutrition and Allerg ies (NDA) ; Guidance on the scientific requirements for health claims related to appetite ratings, weight management, and blood glucose concentrations

    DEFF Research Database (Denmark)

    Tetens, Inge

    The European Food Safety Authority (EFSA) asked the Panel on Dietetic Products, Nutrition and Allergies (NDA) to draft guidance on scientific requirements for health claims related to appetite ratings, weight management, and blood glucose concentrations. This guidance has been drawn from scientific...... and studies/outcome measures which are acceptable. Rather, it presents examples drawn from evaluations already carried out in order to illustrate the approach of the Panel, as well as some examples which are currently under consideration within ongoing evaluations. A draft of this guidance document, endorsed...

  18. Analysis of local perfusion rate (LPR) and local glucose transport rate (LGTR) in brain and heart in man by means of C-11-methyl-D-glucose (CMG) and dynamic positron emission tomography (dPET)

    International Nuclear Information System (INIS)

    Vyska, K.; Freundlieb, C.; Hoeck, A.; Becker, V.; Schmidt, A.; Feinendegen, L.E.; Kloster, G.; Stoecklin, G.; Heiss, W.D.

    1982-01-01

    A method has been developed to measure simultaneously the LPR and LGTR. CMG is used as an indicator. The transaxial distribution of activity in organism is registered with dPET. On the basis of a mathematical model, the LPR and LGTR can be calculated in terms of parameters of the time activity curves registered over different brain or heart regions and over the sup. long. sinus (brain) or the ventricular cavity (heart) (blood activity). The method was used in 10 normal subjects and 20 patients with ischemic brain or heart disease. The values of LGTR range from 0.43 to 0.6 μmol/min g in normal cortex and from 0.09 to 0.12 μmol/min g in normal white matter. The LPR was 0.9-098 ml/min g for the cortex and 0.3-0.4 ml/min g for the white matter. In patients with stroke the ischemic defects appeared to be larger in CMG scans than in CT. The results obtained in a patient with left homonymous hemianopia, caused by infarctions in the distribution area of RMCA, and in a patient with TIA, demonstrate that the inactivation of morphologically intact, cerebral cortex, observed in stroke patients, may be caused by undercutting of cortical fiber tracts as well as by the impairment of the glucose transport systems in the inactivated area. In myocardial studies the LPR in normal left myocardium was 0.68 ml/min g (subendocardium 0.74 ml/min g; subepicardiuim 0.65 ml/min g). In patients with old myocardial infarction, the infarcted areas could be easily recognized as accumulation defects. The results obtained in a patient with narrowing of the RCA indicate that repeated exposure of myocardial tissue to transient ischemia produces an irreversible damage of the glucose transport system. We conclude from the data that for diagnostic evaluation of ultimate brain or heart damage simultaneous quantitative assessment of both LPR and LGTR is of basic importance. (Author)

  19. Influence of phase separation on the anaerobic digestion of glucose: maximum COD turnover rate during continuous operation

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, A; Van Andel, J G; Breure, A M; Van Deursen, A

    1980-01-01

    A mineral medium containing 1% of glucose as the main carbon source was subjected to one-phase and two-phase anaerobic digestion processes under comparable conditions. The one-phase system combined acidogenic and methanogenic populations allowing a complete conversion of the carbon source into gaseous end products and biomass. The two-phase system consists of an acid reactor and a methane reactor connected in series allowing sequential acidogenesis and methanogenesis. Performance of the one-phase system is compared with that of the two-phase system. Maximum turnover of COD was determined for each system. Maximum specific sludge loading of the two-phase system was more than three times higher than that of the one-phase system. Effects of overloading each system were determined. The eco-physiological significance of phase separation is discussed briefly. (2 diagrams, 5 graphs, 41 references, 5 tables)

  20. 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...

  1. The effect of endogenously released glucose, insulin, glucagon-like peptide 1, ghrelin on cardiac output, heart rate, stroke volume, and blood pressure.

    Science.gov (United States)

    Hlebowicz, Joanna; Lindstedt, Sandra; Björgell, Ola; Dencker, Magnus

    2011-12-29

    Ingestion of a meal increases the blood flow to the gastrointestinal organs and affects the heart rate (HR), blood pressure and cardiac output (CO), although the mechanisms are not known. The aim of this study was to evaluate the effect of endogenously released glucose, insulin, glucagon-like peptide 1 (GLP-1), ghrelin on CO, HR, stroke volume (SV), and blood pressure. Eleven healthy men and twelve healthy women ((mean ± SEM) aged: 26 ± 0.2 y; body mass index: 21.8 ± 0.1 kg/m(2))) were included in this study. The CO, HR, SV, systolic and diastolic blood pressure, antral area, gastric emptying rate, and glucose, insulin, GLP-1 and ghrelin levels were measured. The CO and SV at 30 min were significantly higher, and the diastolic blood pressure was significantly lower, than the fasting in both men and women (P blood pressure (P = 0.021, r = -0.681), and the change in SV (P = 0.008, r = -0.748) relative to the fasting in men. The insulin 0-30 min AUC was significantly correlated to the CO 0-30 min AUC (P = 0.002, r = 0.814) in men. Significant correlations were also found between the 0-120 min ghrelin and HR AUCs (P = 0.007, r = 0.966) in men. No statistically significant correlations were seen in women. Physiological changes in the levels of glucose, insulin, GLP-1 and ghrelin may influence the activity of the heart and the blood pressure. There may also be gender-related differences in the haemodynamic responses to postprandial changes in hormone levels. The results of this study show that subjects should not eat immediately prior to, or during, the evaluation of cardiovascular interventions as postprandial affects may affect the results, leading to erroneous interpretation of the cardiovascular effects of the primary intervention. NCT01027507.

  2. Association of glucose homeostasis measures with heart rate variability among Hispanic/Latino adults without diabetes: the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

    Science.gov (United States)

    Meyer, Michelle L; Gotman, Nathan M; Soliman, Elsayed Z; Whitsel, Eric A; Arens, Raanan; Cai, Jianwen; Daviglus, Martha L; Denes, Pablo; González, Hector M; Moreiras, Juan; Talavera, Gregory A; Heiss, Gerardo

    2016-03-16

    Reduced heart rate variability (HRV), a measure of cardiac autonomic function, is associated with an increased risk of cardiovascular disease (CVD) and mortality. Glucose homeostasis measures are associated with reduced cardiac autonomic function among those with diabetes, but inconsistent associations have been reported among those without diabetes. This study aimed to examine the association of glucose homeostasis measures with cardiac autonomic function among diverse Hispanic/Latino adults without diabetes. The Hispanic community Health Study/Study of Latinos (HCHS/SOL; 2008-2011) used two-stage area probability sampling of households to enroll 16,415 self-identified Hispanics/Latinos aged 18-74 years from four USA communities. Resting, standard 12-lead electrocardiogram recordings were used to estimate the following ultrashort-term measures of HRV: RR interval (RR), standard deviation of all normal to normal RR (SDNN) and root mean square of successive differences in RR intervals (RMSSD). Multivariable regression analysis was used to estimate associations between glucose homeostasis measures with HRV using data from 11,994 adults without diabetes (mean age 39 years; 52 % women). Higher fasting glucose was associated with lower RR, SDNN, and RMSSD. Fasting insulin and the homeostasis model assessment of insulin resistance was negatively associated with RR, SDNN, and RMSSD, and the association was stronger among men compared with women. RMSSD was, on average, 26 % lower in men with higher fasting insulin and 29 % lower in men with lower insulin resistance; for women, the corresponding estimates were smaller at 4 and 9 %, respectively. Higher glycated hemoglobin was associated with lower RR, SDNN, and RMSSD in those with abdominal adiposity, defined by sex-specific cut-points for waist circumference, after adjusting for demographics and medication use. There were no associations between glycated hemoglobin and HRV measures among those without abdominal adiposity

  3. 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...

  4. Hepatic glycogen in humans. I. Direct formation after oral and intravenous glucose or after a 24-h fast

    International Nuclear Information System (INIS)

    Radziuk, J.

    1989-01-01

    The formation of hepatic glycogen by the direct pathway is assessed in humans after a 12-h fast and oral loading (100 g) or intravenous infusion (90 g) and after a 24-h fast and the same oral glucose load. The methodology used is based on the double tracer method. [3- 3 H]glucose is infused at a constant rate for the determination of the metabolic clearance of glucose. [1- 14 C]glucose is administered with the glucose load. One hour after absorption or the intravenous glucose infusion is terminated, a glucagon infusion is initiated to mobilize the glycogen labeled with [1- 14 C]glucose and formed during the absorptive period. At this time a third tracer, [6- 3 H]glucose, is administered to measure glucose clearance. It was found that after the 12-h fast and oral glucose loading 7.2 +/- 1.1 g of hepatic glycogen appears to be formed directly from glucose compared with 8.4 +/- 1.0 g after the same load and a 24-h fast and 8.5 +/- 0.4 g after a 12-h fast and an equivalent intravenous glucose infusion. When the amount of label ([ 14 C]glucose) mobilized that was not corrected for metabolic recycling was calculated, the data suggested that the amount of glycogen formed by gluconeogenic pathways was probably at least equal to that formed by direct uptake. It was also approximately 60% greater after a 24-h fast. It can be concluded that the amount of hepatic glycogen formed directly from glucose during glucose loading is not significantly altered by the route of entry or the extension of the fasting period to 24 h. The data suggest, however, that gluconeogenetic formation of glycogen increases with fasting

  5. Analysis of the behavior of an experimental absorption heat transformer for water purification for different mass flux rates in the generator

    International Nuclear Information System (INIS)

    Huicochea, Armando; Rivera, Wilfrido; Martínez, Hiram; Siqueiros, Javier; Cadenas, Erasmo

    2013-01-01

    In the present study, first and second laws of thermodynamics have been used to analyse the performance of an experimental absorption heat transformer for water purification. Irreversibilities, coefficients of performance (COP) and exergy coefficients of performance (ECOP) were determined as function of the mass flow of hot water supplied to the generator and as function of the overall thermal specific energy consumption (OSTEC) parameter defined in this paper. The results showed that the system irreversibilities increase meanwhile the coefficients of performance and the exergy coefficient of performance decrease with an increment of the mass flow of hot water supplied to the generator. Also it was shown that the system performance is better when the production of purified water increases due to the increment of the heat recycled to the generator and evaporator. -- Highlights: ► Exergetic performance of an absorption heat transformer for purifying water to different mass flux rates in the generator. ► The irreversibilities are increasing when the mass flow rate in the generator is major. ► The mass flow rates in the generator plays a decisive role in the whole system efficiency

  6. Living on a trophic subsidy: Algal quality drives an upper-shore herbivore’s consumption, preference and absorption but not growth rates

    Science.gov (United States)

    Quintanilla-Ahumada, Diego; Quijón, Pedro A.; Navarro, Jorge M.; Pulgar, José

    2018-01-01

    The transfer of seaweeds from subtidal bottoms to nearby intertidal rocky shores is a common but often overlooked phenomenon. Freshly detached seaweeds often represent critical trophic subsidies for herbivores living in upper-shore rocky intertidal areas, such as the marine snail Diloma nigerrima. This species relies on three species of seaweeds for food and displays feeding strategies to deal with a resource that is scarce and at times unpredictable. This study focused on the nutritional quality of freshly detached algae (Durvillaea antarctica, Lessonia spicata and Lessonia trabeculata) and measured Diloma nigerrima’s algal consumption rates in trials with and without choice. Absorption efficiency and growth of individual snails fed on each alga were also measured. Durvillaea antarctica had the highest nutritional quality and was the most consumed algae in both single and multiple-choice trials. Absorption efficiency was also highest for D. antarctica but growth rates of snails fed with this species were similar to those fed with the other algae. Combined, these results suggest that D. nigerrima has the ability to discriminate among seaweeds based on their nutritional quality. A potential increase in oxygen uptake when D. nigerrima is consuming the preferred food item is also proposed as a plausible hypothesis to explain the mismatch between snails’ preference and growth rate. These results aim to guide further studies on trophic subsidies and their role in coastal systems. PMID:29672599

  7. The effect of endogenously released glucose, insulin, glucagon-like peptide 1, ghrelin on cardiac output, heart rate, stroke volume, and blood pressure

    Directory of Open Access Journals (Sweden)

    Hlebowicz Joanna

    2011-12-01

    Full Text Available Abstract Background Ingestion of a meal increases the blood flow to the gastrointestinal organs and affects the heart rate (HR, blood pressure and cardiac output (CO, although the mechanisms are not known. The aim of this study was to evaluate the effect of endogenously released glucose, insulin, glucagon-like peptide 1 (GLP-1, ghrelin on CO, HR, stroke volume (SV, and blood pressure. Methods Eleven healthy men and twelve healthy women ((mean ± SEM aged: 26 ± 0.2 y; body mass index: 21.8 ± 0.1 kg/m2 were included in this study. The CO, HR, SV, systolic and diastolic blood pressure, antral area, gastric emptying rate, and glucose, insulin, GLP-1 and ghrelin levels were measured. Results The CO and SV at 30 min were significantly higher, and the diastolic blood pressure was significantly lower, than the fasting in both men and women (P P = 0.015, r = 0.946, and between ghrelin levels and HR (P = 0.013, r = 0.951 at 110 min. Significant correlations were also found between the change in glucose level at 30 min and the change in systolic blood pressure (P = 0.021, r = -0.681, and the change in SV (P = 0.008, r = -0.748 relative to the fasting in men. The insulin 0-30 min AUC was significantly correlated to the CO 0-30 min AUC (P = 0.002, r = 0.814 in men. Significant correlations were also found between the 0-120 min ghrelin and HR AUCs (P = 0.007, r = 0.966 in men. No statistically significant correlations were seen in women. Conclusions Physiological changes in the levels of glucose, insulin, GLP-1 and ghrelin may influence the activity of the heart and the blood pressure. There may also be gender-related differences in the haemodynamic responses to postprandial changes in hormone levels. The results of this study show that subjects should not eat immediately prior to, or during, the evaluation of cardiovascular interventions as postprandial affects may affect the results, leading to erroneous interpretation of the cardiovascular effects of the

  8. Relationship between turnover rate and oxidation rate of alanine in the post-absorptive state and during parenteral nutrition before and after surgery

    NARCIS (Netherlands)

    Sauerwein, H. P.; Michels, R. P.; Cejka, V.

    1985-01-01

    The influence of total parenteral nutrition and stomach resection on alanine turnover rate and alanine oxidation rate was measured in ten patients after single injection of U-14 C-alanine. Sequential studies were done in three patients. During parenteral nutrition alanine turnover was significantly

  9. A study of spin-lattice relaxation rates of glucose, fructose, sucrose and cherries using high-T c SQUID-based NMR in ultralow magnetic fields

    Science.gov (United States)

    Liao, Shu-Hsien; Wu, Pei-Che

    2017-08-01

    We study the concentration dependence of spin-lattice relaxation rates, T 1 -1, of glucose, fructose, sucrose and cherries by using high-T c SQUID-based NMR at magnetic fields of ˜97 μT. The detected NMR signal, Sy (T Bp), is fitted to [1 - exp(-T Bp/T 1)] to derive T 1 -1, where Sy (T Bp) is the strength of the NMR signal, T Bp is the duration of pre-polarization and T 1 -1 is the spin-lattice relaxation rate. It was found that T 1 -1 increases as the sugar concentrations increase. The increased T 1 -1 is due to the presence of more molecules in the surroundings, which increases the spin-lattice interaction and in turn enhances T 1 -1. The T 1 -1 versus degrees Brix curve provides a basis for determining unknown Brix values for cherries as well as other fruits.

  10. Lung inhomogeneities, inflation and [18F]2-fluoro-2-deoxy-D-glucose uptake rate in acute respiratory distress syndrome.

    Science.gov (United States)

    Cressoni, Massimo; Chiumello, Davide; Chiurazzi, Chiara; Brioni, Matteo; Algieri, Ilaria; Gotti, Miriam; Nikolla, Klodiana; Massari, Dario; Cammaroto, Antonio; Colombo, Andrea; Cadringher, Paolo; Carlesso, Eleonora; Benti, Riccardo; Casati, Rosangela; Zito, Felicia; Gattinoni, Luciano

    2016-01-01

    The aim of the study was to determine the size and location of homogeneous inflamed/noninflamed and inhomogeneous inflamed/noninflamed lung compartments and their association with acute respiratory distress syndrome (ARDS) severity.In total, 20 ARDS patients underwent 5 and 45 cmH2O computed tomography (CT) scans to measure lung recruitability. [(18)F]2-fluoro-2-deoxy-d-glucose ([(18)F]FDG) uptake and lung inhomogeneities were quantified with a positron emission tomography-CT scan at 10 cmH2O. We defined four compartments with normal/abnormal [(18)F]FDG uptake and lung homogeneity.The homogeneous compartment with normal [(18)F]FDG uptake was primarily composed of well-inflated tissue (80±16%), double-sized in nondependent lung (32±27% versus 16±17%, pinflation and [(18)F]FDG uptake decreases with ARDS severity, while the inhomogeneous poorly/not inflated compartment increases. Most of the lung inhomogeneities are inflamed. A minor fraction of healthy tissue remains in severe ARDS. Copyright ©ERS 2016.

  11. The Influence of Low Salivary Flow Rates on the Absorption of a Sublingual Fentanyl Citrate Formulation for Breakthrough Cancer Pain.

    Science.gov (United States)

    Davies, Andrew; Mundin, Gill; Vriens, Joanna; Webber, Kath; Buchanan, Alison; Waghorn, Melanie

    2016-03-01

    Salivary gland hypofunction may affect the absorption of drugs through the oral mucosa, which in turn may affect their clinical efficacy (e.g., onset of action). The aim of this study was to assess the pharmacokinetics of a sublingual fentanyl orally disintegrating tablet (Abstral, Prostrakan Inc.) in a group of cancer patients with salivary gland hypofunction. Nine cancer patients with salivary gland hypofunction underwent a series of three pharmacokinetic studies with the sublingual fentanyl orally disintegrating tablet. In the first phase, the patients received no pretreatment; in the second phase, the patients were allowed to moisten the oral cavity before dosing; in the third phase, the patients were given pilocarpine hydrochloride (saliva stimulant) before dosing. Fentanyl concentrations were measured using a method of high-performance liquid chromatography with validated tandem mass spectrometric detection. The Tmax was longer, the Cmax was lower, the AUC0-30 lower, and the AUClast lower in the phase involving no pretreatment; the Tmax/Cmax/AUC0-30/AUClast were similar in the phase involving moistening of the oral cavity and the phase involving giving pilocarpine hydrochloride. The pharmacokinetics of the sublingual fentanyl orally disintegrating tablet appear to be negatively affected by the presence of salivary gland hypofunction, although the moistening of the oral cavity before dosing results in a pharmacokinetic profile similar to that seen with the giving of pilocarpine hydrochloride. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  12. [Effects of different nitrogen application rates on 15N-urea absorption, utilization, loss and fruit yield and quality of dwarf apple].

    Science.gov (United States)

    Chen, Qian; Ding, Ning; Peng, Ling; Ge, Shun Feng; Jiang, Yuan Mao

    2017-07-18

    Seven-year-old 'Yanfu3'/M 26 /M. hupehensis Rehd. seedlings and 15 N trace technique were used to explore the characteristics of 15 N-urea absorption, utilization, loss and fruit yield and quality under different nitrogen application rates (N 100 , N 200 and N 300 ). The main results were as follows: the plant growth, 15 N absorption, utilization and loss differed significantly under different treatments. The plant leaf chlorophyll content (SPAD value), photosynthetic rate (P n ), total N content of leaves and the biomass, as well as the root-shoot ratio of N 200 treatment were obviously higher than the N 100 and N 300 treatments. Significant differences were observed in the 15 N derived from fertilizer (Ndff value) of different organs under different nitrogen application rates. The Ndff of fruits (flowers), leaves, one-year-old branch, and perennial branches in each measurement period was N 100 >N 200 >N 300 , while that of the roots at full-bloom and spring shoot growing slowly stage was N 100 >N 200 >N 300 , and in a trend of N 200 >N 100 >N 300 at autumn shoot growing stage, fruit rapid-swel-ling stage and fruit maturity stage. At fruit maturity stage, plant 15 N nitrogen utilization ratio of N 200 treatment was 23.6%, which was obviously higher than the N 100 (16.3%) and N 300 (14.4%) treatments, with the 15 N loss rate of 56.4%, obviously lower than the N 100 (60.6%) and N 300 (66.1%) treatments. There were significant differences among the treatments in fruit mass, yield per plant, soluble solid, fruit firmness, soluble sugar, titratable acids and sugar-acid ratio of different nitrogen rates, and the N 200 treatment showed the best performance, followed by the N 300 treatment, and then the N 100 treatment.

  13. The effects of receiving room dimensions and absorption in the measurement of impact insulation class (IIC) rating

    Science.gov (United States)

    Su, Rose Mary; Tocci, Gregory

    2005-09-01

    The measurement of the Impact Insulation Class (IIC) rating of any floor/ceiling construction requires the use of a certified laboratory space. In a recent investigation into the IIC rating of a new floor system, several tests were conducted in a certified laboratory. In many tests, the IIC rating was controlled by the 100-Hz 1/3-octave frequency band, despite changes in the floor/ceiling construction. The base floor/ceiling construction included a wood structural floor on open-web wood joists and a GWB ceiling below. This paper will investigate the possibility that room resonances influenced the IIC ratings of the several floor systems tested. These data will be compared with IIC data collected for the same floor construction with the GWB ceiling removed. The removal of the GWB ceiling increased the receiver room volume and exposed the glass fiber insulation to the receiver room, thus eliminating the control of the 100-Hz 1/3-octave band over the IIC rating.

  14. Tumor Delineation and Quantitative Assessment of Glucose Metabolic Rate within Histologic Subtypes of Non-Small Cell Lung Cancer by Using Dynamic 18F Fluorodeoxyglucose PET.

    Science.gov (United States)

    Meijer, Tineke W H; de Geus-Oei, Lioe-Fee; Visser, Eric P; Oyen, Wim J G; Looijen-Salamon, Monika G; Visvikis, Dimitris; Verhagen, Ad F T M; Bussink, Johan; Vriens, Dennis

    2017-05-01

    Purpose To assess whether dynamic fluorine 18 ( 18 F) fluorodeoxyglucose (FDG) positron emission tomography (PET) has added value over static 18 F-FDG PET for tumor delineation in non-small cell lung cancer (NSCLC) radiation therapy planning by using pathology volumes as the reference standard and to compare pharmacokinetic rate constants of 18 F-FDG metabolism, including regional variation, between NSCLC histologic subtypes. Materials and Methods The study was approved by the institutional review board. Patients gave written informed consent. In this prospective observational study, 1-hour dynamic 18 F-FDG PET/computed tomographic examinations were performed in 35 patients (36 resectable NSCLCs) between 2009 and 2014. Static and parametric images of glucose metabolic rate were obtained to determine lesion volumes by using three delineation strategies. Pathology volume was calculated from three orthogonal dimensions (n = 32). Whole tumor and regional rate constants and blood volume fraction (V B ) were computed by using compartment modeling. Results Pathology volumes were larger than PET volumes (median difference, 8.7-25.2 cm 3 ; Wilcoxon signed rank test, P PET images is in best agreement with pathology volume and could be useful for NSCLC autocontouring. Differences in glycolytic rate and V B between SCC and AC are relevant for research in targeting agents and radiation therapy dose escalation. © RSNA, 2016 Online supplemental material is available for this article.

  15. Measurement of the rate of hydrogen peroxide thermal decomposition in a shock tube using quantum cascade laser absorption near 7.7 μm

    KAUST Repository

    Sajid, Muhammad Bilal

    2013-10-24

    Hydrogen peroxide (H2O2) is formed during hydrocarbon combustion and controls the system reactivity under intermediate temperature conditions. Here, we measured the rate of hydrogen peroxide decomposition behind reflected shock waves using midinfrared absorption of H2O 2 near 7.7 μm. We performed the experiments in diluted H 2O2/Ar mixtures between 930 and 1235 K and at three different pressures (1, 2, and 10 atm). Under these conditions, the decay of hydrogen peroxide is sensitive only to the decomposition reaction rate, H 2O2 + M → 2OH + M (k1). The second-order rate coefficient at low pressures (1 and 2 atm) did not exhibit any pressure dependence, suggesting that the reaction was in the low-pressure limit. The rate data measured at 10 atm exhibited falloff behavior. The measured decomposition rates can be expressed in Arrhenius forms as follows: k1(1 and 2 atm)=10(16.29±0.12)× exp (-21993±301/T)(cm 3 mol -1s-1) k1(10 atm)=10(15.24±0.10)× exp (-19955±247/T)(cm 3 mol -1s-1) © 2013 Wiley Periodicals, Inc.

  16. A study of the tyramine/glucose Maillard reaction: Variables, characterization, cytotoxicity and preliminary application.

    Science.gov (United States)

    Jiang, Wei; Chen, Yaxin; He, Xiaoxia; Hu, Shiwei; Li, Shijie; Liu, Yu

    2018-01-15

    The tyramine/glucose Maillard reaction was proposed as an emerging tool for tyramine reduction in a model system and two commercial soy sauce samples. The model system was composed of tyramine and glucose in buffer solutions with or without NaCl. The results showed that tyramine was reduced in the model system, and the reduction rate was affected by temperature, heating time, initial pH value, NaCl concentration, initial glucose concentration and initial tyramine concentration. Changes in fluorescence intensity and ultraviolet-visible (UV-vis) absorption spectra showed three stages of the Maillard reaction between tyramine and glucose. Cytotoxicity assay demonstrated that tyramine/glucose Maillard reaction products (MRPs) were significantly less toxic than that of tyramine (pMaillard reaction is a promising method for tyramine reduction in foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Influence of the oral dissolution time on the absorption rate of locally administered solid formulations for oromucosal use: the flurbiprofen lozenges paradigm.

    Science.gov (United States)

    Imberti, Roberto; De Gregori, Simona; Lisi, Lucia; Navarra, Pierluigi

    2014-01-01

    Flurbiprofen is a nonsteroidal anti-inflammatory agent preferentially used for local oromucosal treatment of painful and/or inflammatory conditions of the oropharynx such as gingivitis, stomatitis, periodontitis, pharyngitis and laryngitis. In this study, we have investigated the bioavailability of a new generic formulation of flurbiprofen lozenges developed by Epifarma Srl, compared to the originator Benactiv Gola® taken as reference. Within the framework of a formal bioequivalence study, we investigated in particular the putative influence of oral dissolution time (i.e. the time spent suckling the lozenge from its intake to complete dissolution) on the absorption rate, and the contribution of this factor to the total variability of plasma flurbiprofen during absorption. We found that the amount of flurbiprofen absorbed into the systemic circulation is not significantly higher for the test drug compared to that of the reference product. We observed that the length of oral dissolution time is inversely correlated to 10-min flurbiprofen plasma levels in the test but not in the reference formulation. We estimated that oral dissolution time accounts for about 14% of overall variability in flurbiprofen plasma 10 min after test drug administration. © 2014 S. Karger AG, Basel.

  18. Generation of a head phantom according to the 95. percentile Chinese population data for evaluating the specific absorption rate by wireless communication devices

    International Nuclear Information System (INIS)

    Ma, Yu; Wang, Yuduo; Shao, Qing; Wu, Tongning; Li, Congsheng

    2014-01-01

    A Chinese head phantom (CHP) is constructed for evaluating the specific absorption rate (SAR) by the wireless transceivers. The dimensions of the head phantom are within 4 % difference compared with the 95. percentile data from the China's standard. The shell's thickness and the configuration of the pinna are the same as those of the specific anthropomorphic mannequin (SAM). Three computable models for the mobile phones are generated and used in the SAR simulations with the SAM and the CHP. The results show that the simulated SAR from the SAM head is similar. Its morphological reason has been analysed. The authors discuss the conservativeness of the two head phantoms as well. The CHP can be used in the inter-laboratory evaluation for the SAR uncertainty. It can also provide the information for the SAR variability due to physical difference, which will benefit the maintenance and the harmonisation of the standards. (authors)

  19. A randomized cross-over study of the acute effects of running 5 km on glucose, insulin, metabolic rate, cortisol and Troponin T.

    Science.gov (United States)

    Keselman, Boris; Vergara, Marta; Nyberg, Sofia; Nystrom, Fredrik H

    2017-01-01

    We aimed to study the impact by running 5 km, at maximal speed, on the normal variations of metabolic variables related to glucose, insulin, insulin sensitivity, cortisol, glucagon, Troponin T and metabolic rate. Five women and 12 men 25.7±5.2 years of age with a body-mass-index of 22.5±2.3 kg/m2 where recruited to run 5 km at individual maximal speed in the morning, and to a corresponding day of rest, followed by standardized breakfast and lunch meals. Blood sampling and measurement of indirect calorimetry were done before and after meals. The participants were randomized regarding the order of the two trial-days in this cross-over study. Insulin and cortisol levels were higher, and insulin sensitivity was lower, on the race-day compared with the day of rest (linear mixed model: pdays (p = 0.29 and p = 0.53, respectively). When analyzing specific time-points we found that glucose increased from 5.01±0.37 mmol/l to 6.36 ± 1.3 mmol/l, pindex of serum sensitivity, 1/(log10insulin+log10glucose), was lowered post-race, p<0.0001. Serum cortisol levels increased from 408±137 nmol/l to 644±171 nmol/l, p<0.0001, post-race while serum glucagon levels were unaffected. Troponin T was detectable in serum post-race in 12 out of the 17 participants and reached or surpassed the clinical reference level of 15 ng/l in three subjects. Post-race electrocardiograms displayed no pathologies. Relatively short running-races can apparently induce a reduction in insulin sensitivity that is not fully compensated by concomitantly increased insulin secretion intended to ensure euglycemia. Since also Troponin T was detected in plasma in a majority of the participants, our data suggest that it is possible to induce considerable metabolic stress by running merely 5 km, when striving for maximal speed.

  20. The COS/UVES absorption survey of the Magellanic stream. III. Ionization, total mass, and inflow rate onto the Milky Way

    International Nuclear Information System (INIS)

    Fox, Andrew J.; Thom, Christopher; Tumlinson, Jason; Ely, Justin; Kumari, Nimisha; Wakker, Bart P.; Hernandez, Audra K.; Haffner, L. Matthew; Barger, Kathleen A.; Lehner, Nicolas; Howk, J. Christopher; Richter, Philipp; Bland-Hawthorn, Joss; Charlton, Jane C.; Westmeier, Tobias; Misawa, Toru; Rodriguez-Hidalgo, Paola

    2014-01-01

    Dynamic interactions between the two Magellanic Clouds have flung large quantities of gas into the halo of the Milky Way. The result is a spectacular arrangement of gaseous structures, including the Magellanic Stream, the Magellanic Bridge, and the Leading Arm (collectively referred to as the Magellanic System). In this third paper of a series studying the Magellanic gas in absorption, we analyze the gas ionization level using a sample of 69 Hubble Space Telescope/Cosmic Origins Spectrograph sightlines that pass through or within 30° of the 21 cm emitting regions. We find that 81% (56/69) of the sightlines show UV absorption at Magellanic velocities, indicating that the total cross-section of the Magellanic System is ≈11,000 deg 2 , or around one-quarter of the entire sky. Using observations of the Si III/Si II ratio together with Cloudy photoionization modeling, we calculate the total gas mass (atomic plus ionized) of the Magellanic System to be ≈2.0 × 10 9 M ☉ (d/55 kpc) 2 , with the ionized gas contributing around three times as much mass as the atomic gas. This is larger than the current-day interstellar H I mass of both Magellanic Clouds combined, indicating that they have lost most of their initial gas mass. If the gas in the Magellanic System survives to reach the Galactic disk over its inflow time of ∼0.5-1.0 Gyr, it will represent an average inflow rate of ∼3.7-6.7 M ☉ yr –1 , potentially raising the Galactic star formation rate. However, multiple signs of an evaporative interaction with the hot Galactic corona indicate that the Magellanic gas may not survive its journey to the disk fully intact and will instead add material to (and cool) the corona.

  1. The COS/UVES absorption survey of the Magellanic stream. III. Ionization, total mass, and inflow rate onto the Milky Way

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Andrew J.; Thom, Christopher; Tumlinson, Jason; Ely, Justin; Kumari, Nimisha [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Wakker, Bart P.; Hernandez, Audra K.; Haffner, L. Matthew [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Barger, Kathleen A.; Lehner, Nicolas; Howk, J. Christopher [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Richter, Philipp [Institut für Physik und Astronomie, Universität Potsdam, Haus 28, Karl-Liebknecht-Strasse 24/25, D-14476, Potsdam (Germany); Bland-Hawthorn, Joss [Institute of Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Charlton, Jane C. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Westmeier, Tobias [ICRAR, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Misawa, Toru [School of General Education, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Rodriguez-Hidalgo, Paola, E-mail: afox@stsci.edu [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, ON M3J 1P3 (Canada)

    2014-06-01

    Dynamic interactions between the two Magellanic Clouds have flung large quantities of gas into the halo of the Milky Way. The result is a spectacular arrangement of gaseous structures, including the Magellanic Stream, the Magellanic Bridge, and the Leading Arm (collectively referred to as the Magellanic System). In this third paper of a series studying the Magellanic gas in absorption, we analyze the gas ionization level using a sample of 69 Hubble Space Telescope/Cosmic Origins Spectrograph sightlines that pass through or within 30° of the 21 cm emitting regions. We find that 81% (56/69) of the sightlines show UV absorption at Magellanic velocities, indicating that the total cross-section of the Magellanic System is ≈11,000 deg{sup 2}, or around one-quarter of the entire sky. Using observations of the Si III/Si II ratio together with Cloudy photoionization modeling, we calculate the total gas mass (atomic plus ionized) of the Magellanic System to be ≈2.0 × 10{sup 9} M {sub ☉} (d/55 kpc){sup 2}, with the ionized gas contributing around three times as much mass as the atomic gas. This is larger than the current-day interstellar H I mass of both Magellanic Clouds combined, indicating that they have lost most of their initial gas mass. If the gas in the Magellanic System survives to reach the Galactic disk over its inflow time of ∼0.5-1.0 Gyr, it will represent an average inflow rate of ∼3.7-6.7 M {sub ☉} yr{sup –1}, potentially raising the Galactic star formation rate. However, multiple signs of an evaporative interaction with the hot Galactic corona indicate that the Magellanic gas may not survive its journey to the disk fully intact and will instead add material to (and cool) the corona.

  2. A shock tube and laser absorption study of ignition delay times and OH reaction rates of ketones: 2-Butanone and 3-buten-2-one

    KAUST Repository

    Badra, Jihad

    2014-03-01

    Ketones are potential biofuel candidates and are also formed as intermediate products during the oxidation of large hydrocarbons or oxygenated fuels, such as alcohols and esters. This paper presents shock tube ignition delay times and OH reaction rates of 2-butanone (C2H5COCH3) and 3-buten-2-one (C2H3COCH3). Ignition delay measurements were carried out over temperatures of 1100-1400K, pressures of 3-6.5atm, and at equivalence ratios (F{cyrillic}) of 0.5 and 1. Ignition delay times were monitored using two different techniques: pressure time history and OH absorption near 306nm. The reaction rates of hydroxyl radicals (OH) with these two ketones were measured over the temperature range of 950-1400K near 1.5atm. The OH profiles were monitored by the narrow-line-width ring-dye laser absorption of the well-characterized R1(5) line in the OH A-X (0, 0) band near 306.69nm. We found that the ignition delay times of 2-butanone and 3-buten-2-one mixtures scale with pressure as P-0.42 and P-0.52, respectively. The ignition delay times of 3-buten-2-one were longer than that of 2-butanone for stoichiometric mixtures, however, for lean mixtures (F{cyrillic}=0.5), 2-butanone had longer ignition delay times. The chemical kinetic mechanism of Serinyel et al. [1] over-predicted the ignition delay times of 2-butanone at all tested conditions, however, the discrepancies were smaller at higher pressures. The mechanism was updated with recent rate measurements to decrease discrepancy with the experimental data. A detailed chemistry for the oxidation of 3-buten-2-one was developed using rate estimation method and reasonable agreements were obtained with the measured ignition delay data. The measured reaction rate of 2-butanone with OH agreed well with the literature data, while we present the first high-temperature measurements for the reaction of OH with 3-buten-2-one. The following Arrhenius expressions are suggested over the temperature range of 950-1450K: kC2H5COCH3+OH=6.78×1013exp

  3. Visualization and quantification of heterogeneous diffusion rates in granodiorite samples by X-ray absorption imaging. Diffusion within gouge materials, altered rim and intact rock matrix

    International Nuclear Information System (INIS)

    Altman, S.J.; Tidwell, V.C.; Uchida, M.

    2001-01-01

    Matrix diffusion is one of the most important contaminant migration retardation processes in crystalline rocks. Performance assessment calculations in various countries assume that only the area of the fracture surface where advection is active provides access to the rock matrix. However, accessibility to the matrix could be significantly enhanced with diffusion into stagnant zones, fracture fillings, and through an alteration rim in the matrix. Laboratory visualization experiments were conducted on granodiorite samples to investigate and quantify diffusion rates within different zones of a Cretaceous granodiorite. Samples were collected from the Kamaishi experimental site in the northern part of the main island of Japan. Diffusion of iodine out of the sample is visualized and rates are measured using x-ray absorption imaging. X-ray images allow for measurements of relative iodine concentration and relative iodine mass as a function of time and two-dimensional space at a sub-millimeter spatial resolution. In addition, two-dimensional heterogeneous porosity fields (at the same resolution as the relative concentration fields) are measured. This imaging technique allows for a greater understanding of the spatial variability of diffusion rates than can be accomplished with standard bulk measurements. It was found that diffusion rates were fastest in partially gouge-filled fractures. Diffusion rates in the recrystallized calcite-based fracture-filling material were up to an order of magnitude lower than in gouge-filled fractures. Diffusion in altered matrix around the fractures was over an order of magnitude lower than that in the gouge-filled fractures. Healed fractures did not appear to have different diffusion rates than the unaltered matrix

  4. Visualization and quantification of heterogeneous diffusion rates in granodiorite samples by X-ray absorption imaging. Diffusion within gouge materials, altered rim and intact rock matrix

    Energy Technology Data Exchange (ETDEWEB)

    Altman, S.J.; Tidwell, V.C. [Sandia National Laboratories, Albuquerque, NM (United States); Uchida, M. [Japan Nuclear Cycle Development Inst., Ibaraki (Japan)

    2001-08-01

    Matrix diffusion is one of the most important contaminant migration retardation processes in crystalline rocks. Performance assessment calculations in various countries assume that only the area of the fracture surface where advection is active provides access to the rock matrix. However, accessibility to the matrix could be significantly enhanced with diffusion into stagnant zones, fracture fillings, and through an alteration rim in the matrix. Laboratory visualization experiments were conducted on granodiorite samples to investigate and quantify diffusion rates within different zones of a Cretaceous granodiorite. Samples were collected from the Kamaishi experimental site in the northern part of the main island of Japan. Diffusion of iodine out of the sample is visualized and rates are measured using x-ray absorption imaging. X-ray images allow for measurements of relative iodine concentration and relative iodine mass as a function of time and two-dimensional space at a sub-millimeter spatial resolution. In addition, two-dimensional heterogeneous porosity fields (at the same resolution as the relative concentration fields) are measured. This imaging technique allows for a greater understanding of the spatial variability of diffusion rates than can be accomplished with standard bulk measurements. It was found that diffusion rates were fastest in partially gouge-filled fractures. Diffusion rates in the recrystallized calcite-based fracture-filling material were up to an order of magnitude lower than in gouge-filled fractures. Diffusion in altered matrix around the fractures was over an order of magnitude lower than that in the gouge-filled fractures. Healed fractures did not appear to have different diffusion rates than the unaltered matrix.

  5. Insulin induces a positive relationship between the rates of ATP and glycogen changes in isolated rat liver in presence of glucose; a 31P and 13C NMR study

    Directory of Open Access Journals (Sweden)

    Gin Henri

    2005-11-01

    Full Text Available Abstract Background There is an emerging theory suggesting that insulin, which is known to be the predominant postprandial anabolic hormone, is also a major regulator of mitochondrial oxidative phosphorylation in human skeletal muscle. However, little is known about its effects in the liver. Since there is a theoretical relationship between glycogen metabolism and energy status, a simultaneous and continuous investigation of hepatic ATP and glycogen content was performed in intact and isolated perfused liver by 31P and 13C nuclear magnetic resonance (NMR The hepatic rates of ATP and glycogen changes were evaluated with different concentrations of insulin and glucose during continuous and short-term supply. Results Liver from rats fed ad libitum were perfused with Krebs-Henseleit Buffer (KHB(controls or KHB containing 6 mM glucose, 30 mM glucose, insulin alone, insulin + 6 mM glucose, insulin + 30 mM glucose. In the control, glycogenolysis occurred at a rate of -0.53 ± 0.021 %·min-1 and ATP content decreased at a rate of -0.28 ± 0.029 %·min-1. In the absence of insulin, there was a close proportional relationship between the glycogen flux and the glucose concentration, whereas ATP rates never varied. With insulin + glucose, both glycogen and ATP rates were strongly related to the glucose concentration; the magnitude of net glycogen flux was linearly correlated to the magnitude of net ATP flux: fluxglycogen = 72.543(fluxATP + 172.08, R2 = 0.98. Conclusion Only the co-infusion of 30 mM glucose and insulin led to (i a net glycogen synthesis, (ii the maintenance of the hepatic ATP content, and a strong positive correlation between their net fluxes. This has never previously been reported. The specific effect of insulin on ATP change is likely related to a rapid stimulation of the hepatic mitochondrial oxidative phosphorylation. We propose that variations in the correlation between rates of ATP and glycogen changes could be a probe for insulin

  6. Insulin induces a positive relationship between the rates of ATP and glycogen changes in isolated rat liver in presence of glucose; a 31P and 13C NMR study.

    Science.gov (United States)

    Baillet-Blanco, Laurence; Beauvieux, Marie-Christine; Gin, Henri; Rigalleau, Vincent; Gallis, Jean-Louis

    2005-11-21

    There is an emerging theory suggesting that insulin, which is known to be the predominant postprandial anabolic hormone, is also a major regulator of mitochondrial oxidative phosphorylation in human skeletal muscle. However, little is known about its effects in the liver. Since there is a theoretical relationship between glycogen metabolism and energy status, a simultaneous and continuous investigation of hepatic ATP and glycogen content was performed in intact and isolated perfused liver by 31P and 13C nuclear magnetic resonance (NMR) The hepatic rates of ATP and glycogen changes were evaluated with different concentrations of insulin and glucose during continuous and short-term supply. Liver from rats fed ad libitum were perfused with Krebs-Henseleit Buffer (KHB)(controls) or KHB containing 6 mM glucose, 30 mM glucose, insulin alone, insulin + 6 mM glucose, insulin + 30 mM glucose. In the control, glycogenolysis occurred at a rate of -0.53 +/- 0.021 % x min(-1) and ATP content decreased at a rate of -0.28 +/- 0.029 % x min(-1). In the absence of insulin, there was a close proportional relationship between the glycogen flux and the glucose concentration, whereas ATP rates never varied. With insulin + glucose, both glycogen and ATP rates were strongly related to the glucose concentration; the magnitude of net glycogen flux was linearly correlated to the magnitude of net ATP flux: flux(glycogen) = 72.543(fluxATP) + 172.08, R2 = 0.98. Only the co-infusion of 30 mM glucose and insulin led to (i) a net glycogen synthesis, (ii) the maintenance of the hepatic ATP content, and a strong positive correlation between their net fluxes. This has never previously been reported. The specific effect of insulin on ATP change is likely related to a rapid stimulation of the hepatic mitochondrial oxidative phosphorylation. We propose that variations in the correlation between rates of ATP and glycogen changes could be a probe for insulin resistance due to the action of substrates

  7. Absorption of folic acid and its rate of disappearance from the blood of patients receiving barbiturates in excess in combination with alcohol

    International Nuclear Information System (INIS)

    Gyftaki, H.; Kesse-Elias, M.; Alevizou-Terzaki, V.; Rapidis, P.; Sdougou-Christakopoulou, J.

    1975-01-01

    It is known that megaloblastic anaemia may occur from the intake of phenobarbital, which apparently responds to folic acid and vitamin B 12 . Its site of action is not known but there is evidence that it may act as a pyrimidine antagonist. It is also known that alcoholics with or without cirrhosis have folate deficiency. Furthermore, although potentiating effects of alcohol and barbiturates exist it is not known how the combination of barbiturates and alcohol acts on folic acid metabolism. In thirty patients receiving barbiturates in excess in combination with alcohol, absorption of folic acid and its rate of disappearance were studied in the blood. Two series of studies were performed. In the first, folic acid (15μg/kg of body weight) was administered orally and the maximum concentration in the blood as well as its disappearance rate were determined. In the second, folinic acid (15 μg/kg of body weight) was administered intramuscularly and the disappearance rate of folic acid was again determined. Blood samples were taken at certain intervals after administration of folic or folinic acid. Estimation of serum folic acid level was obtained by a competitive protein-binding technique developed in our laboratory. The results are discussed and compared with those in normal subjects. (author)

  8. Determination of glucose exchange rates and permeability of erythrocyte membrane in preeclampsia and subsequent oxidative stress-related protein damage using dynamic-{sup 19}F-NMR

    Energy Technology Data Exchange (ETDEWEB)

    Dickinson, Elizabeth, E-mail: elizabeth.dickinson@york.ac.uk [University of York, Department of Chemistry (United Kingdom); Arnold, John R. P. [Selby College (United Kingdom); Fisher, Julie [University of Leeds, School of Chemistry (United Kingdom)

    2017-02-15

    The cause of the pregnancy condition preeclampsia (PE) is thought to be endothelial dysfunction caused by oxidative stress. As abnormal glucose tolerance has also been associated with PE, we use a fluorinated-mimic of this metabolite to establish whether any oxidative damage to lipids and proteins in the erythrocyte membrane has increased cell membrane permeability. Data were acquired using {sup 19}F Dynamic-NMR (DNMR) to measure exchange of 3-fluoro-3-deoxyglucose (3-FDG) across the membrane of erythrocytes from 10 pregnant women (5 healthy control women, and 5 from women suffering from PE). Magnetisation transfer was measured using the 1D selective inversion and 2D EXSY pulse sequences, over a range of time delays. Integrated intensities from these experiments were used in matrix diagonalisation to estimate the values of the rate constants of exchange and membrane permeability. No significant differences were observed for the rate of exchange of 3-FDG and membrane permeability between healthy pregnant women and those suffering from PE, leading us to conclude that no oxidative damage had occurred at this carrier-protein site in the membrane.

  9. Determination of glucose exchange rates and permeability of erythrocyte membrane in preeclampsia and subsequent oxidative stress-related protein damage using dynamic-"1"9F-NMR

    International Nuclear Information System (INIS)

    Dickinson, Elizabeth; Arnold, John R. P.; Fisher, Julie

    2017-01-01

    The cause of the pregnancy condition preeclampsia (PE) is thought to be endothelial dysfunction caused by oxidative stress. As abnormal glucose tolerance has also been associated with PE, we use a fluorinated-mimic of this metabolite to establish whether any oxidative damage to lipids and proteins in the erythrocyte membrane has increased cell membrane permeability. Data were acquired using "1"9F Dynamic-NMR (DNMR) to measure exchange of 3-fluoro-3-deoxyglucose (3-FDG) across the membrane of erythrocytes from 10 pregnant women (5 healthy control women, and 5 from women suffering from PE). Magnetisation transfer was measured using the 1D selective inversion and 2D EXSY pulse sequences, over a range of time delays. Integrated intensities from these experiments were used in matrix diagonalisation to estimate the values of the rate constants of exchange and membrane permeability. No significant differences were observed for the rate of exchange of 3-FDG and membrane permeability between healthy pregnant women and those suffering from PE, leading us to conclude that no oxidative damage had occurred at this carrier-protein site in the membrane.

  10. 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...

  11. The relationship of temperature rise to specific absorption rate and current in the human leg for exposure to electromagnetic radiation in the high frequency band

    International Nuclear Information System (INIS)

    Wainwright, P R

    2003-01-01

    Of the biological effects of human exposure to radiofrequency and microwave radiation, the best-established are those due to elevation of tissue temperature. To prevent harmful levels of heating, restrictions have been proposed on the specific absorption rate (SAR). However, the relationship between SAR and temperature rise is not an invariant, since not only the heat capacity but also the efficiency of heat dissipation varies between different tissues and exposure scenarios. For small enough SAR, the relationship is linear and may be characterized by a 'heating factor'. Under whole-body irradiation the SAR may be particularly high in the ankles due to the concentration of current flowing through a relatively small cross-sectional area. In a previous paper, the author has presented calculations of the SAR distribution in a human leg in the high frequency (HF) band. In this paper, the heating factor for this situation is derived using a finite element approximation of the Pennes bio-heat equation. The sensitivity of the results to different blood perfusion rates is investigated, and a simple local thermoregulatory model is applied. Both time-dependent and steady-state solutions are considered. Results confirm the appropriateness of the ICNIRP reference level of 100 mA on current through the leg, but suggest that at higher currents significant thermoregulatory adjustments to muscle blood flow will occur

  12. Calcium absorption

    International Nuclear Information System (INIS)

    Carlmark, B.; Reizenstein, P.; Dudley, R.A.

    1976-01-01

    The methods most commonly used to measure the absorption and retention of orally administered calcium are reviewed. Nearly all make use of calcium radioisotopes. The magnitude of calcium absorption and retention depends upon the chemical form and amount of calcium administered, and the clinical and nutritional status of the subject; these influences are briefly surveyed. (author)

  13. Assessment of myocardial metabolic rate of glucose by means of Bayesian ICA and Markov Chain Monte Carlo methods in small animal PET imaging

    Science.gov (United States)

    Berradja, Khadidja; Boughanmi, Nabil

    2016-09-01

    In dynamic cardiac PET FDG studies the assessment of myocardial metabolic rate of glucose (MMRG) requires the knowledge of the blood input function (IF). IF can be obtained by manual or automatic blood sampling and cross calibrated with PET. These procedures are cumbersome, invasive and generate uncertainties. The IF is contaminated by spillover of radioactivity from the adjacent myocardium and this could cause important error in the estimated MMRG. In this study, we show that the IF can be extracted from the images in a rat heart study with 18F-fluorodeoxyglucose (18F-FDG) by means of Independent Component Analysis (ICA) based on Bayesian theory and Markov Chain Monte Carlo (MCMC) sampling method (BICA). Images of the heart from rats were acquired with the Sherbrooke small animal PET scanner. A region of interest (ROI) was drawn around the rat image and decomposed into blood and tissue using BICA. The Statistical study showed that there is a significant difference (p corrupted with spillover.

  14. Metabolic Profiling Reveals Differences in Plasma Concentrations of Arabinose and Xylose after Consumption of Fiber-Rich Pasta and Wheat Bread with Differential Rates of Systemic Appearance of Exogenous Glucose in Healthy Men

    NARCIS (Netherlands)

    Pantophlet, Andre J.; Wopereis, Suzan; Eelderink, Coby; Vonk, Roel J.; Stroeve, Johanna H.; Bijlsma, Sabina; van Stee, Leo; Bobeldijk, Ivana; Priebes, Marion G.

    2017-01-01

    Background: The consumption of products rich in cereal fiber and with a low glycemic index is implicated in a lower risk of metabolic diseases. Previously, we showed that the consumption of fiber-rich pasta compared with bread resulted in a lower rate of appearance of exogenous glucose and a lower

  15. Absorption studies

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    Absorption studies were once quite popular but hardly anyone does them these days. It is easier to estimate the blood level of the nutrient directly by radioimmunoassay (RIA). However, the information obtained by estimating the blood levels of the nutrients is not the same that can be obtained from the absorption studies. Absorption studies are primarily done to find out whether some of the essential nutrients are absorbed from the gut or not and if they are absorbed, to determine how much is being absorbed. In the advanced countries, these tests were mostly done to detect pernicious anaemia where vitamin B 12 is not absorbed because of the lack of the intrinsic factor in the stomach. In the tropical countries, ''malabsorption syndrome'' is quire common. In this condition, several nutrients like fat, folic acid and vitamin B 12 are not absorbed. It is possible to study absorption of these nutrients by radioisotopic absorption studies

  16. Effect of Microenvironmental pH Modulation on the Dissolution Rate and Oral Absorption of the Salt of a Weak Acid - Case Study of GDC-0810.

    Science.gov (United States)

    Hou, Hao Helen; Jia, Wei; Liu, Lichuan; Cheeti, Sravanthi; Li, Jane; Nauka, Ewa; Nagapudi, Karthik

    2018-01-29

    The purpose of this work is to investigate the effect of microenvironmental pH modulation on the in vitro dissolution rate and oral absorption of GDC-0810, an oral anti-cancer drug, in human. The pH-solubility profile of GDC-0810 free acid and pH max of its N-Methyl-D-glucamine (NMG) salt were determined. Precipitation studies were conducted for GDC-0810 NMG salt at different pH values. GDC-0810 200-mg dose NMG salt tablet formulations containing different levels of sodium bicarbonate as the pH modifier were tested for dissolution under the dual pH-dilution scheme. Three tablet formulations were evaluated in human as a part of a relative bioavailability study. A 200-mg dose of GDC-0810 was administered QD with low fat food. Intrinsic solubility of GDC-0810 free acid was found to be extremely low. The pH max of the NMG salt suggested a strong tendency for form conversion to the free acid under GI conditions. In vitro dissolution profiles showed that the dissolution rate and extent of GDC-0810 increased with increasing the level of sodium bicarbonate in the formulation. The human PK data showed a similar trend for the geometric mean of C max and AUC 0-t for formulations containing 5%, 10%, and 15% sodium bicarbonate, but the difference is not statistically significant. Incorporation of a basic pH modifier, sodium bicarbonate, in GDC-0810 NMG salt tablet formulations enhanced in vitro dissolution rate of GDC-0810 via microenvironmental pH modulation. The human PK data showed no statistically significant difference in drug exposure from tablets containing 5%, 10%, and 15% sodium bicarbonate.

  17. Comparison of FDTD-calculated specific absorption rate in adults and children when using a mobile phone at 900 and 1800 MHz

    International Nuclear Information System (INIS)

    MartInez-Burdalo, M; MartIn, A; Anguiano, M; Villar, R

    2004-01-01

    In this paper, the specific absorption rate (SAR) in scaled human head models is analysed to study possible differences between SAR in the heads of adults and children and for assessment of compliance with the international safety guidelines, while using a mobile phone. The finite-difference time-domain method (FDTD) has been used for calculating SAR values for models of both children and adults, at 900 and 1800 MHz. Maximum 1 g averaged SAR (SAR 1g ) and maximum 10 g averaged SAR (SAR 10g ) have been calculated in adults and scaled head models for comparison and assessment of compliance with ANSI/IEEE and European guidelines. Results show that peak SAR 1g and peak SAR 10g all trend downwards with decreasing head size but as head size decreases, the percentage of energy absorbed in the brain increases. So, higher SAR in children's brains can be expected depending on whether the thickness of their skulls and surrounding tissues actually depends on age. The SAR in eyes of different sizes, as a critical organ, has also been studied and very similar distributions for the full size and the scaled models have been obtained. Standard limits can only be exceeded in the unpractical situation where the antenna is located at a very short distance in front of the eye

  18. Comparison of FDTD-calculated specific absorption rate in adults and children when using a mobile phone at 900 and 1800 MHz

    Energy Technology Data Exchange (ETDEWEB)

    MartInez-Burdalo, M; MartIn, A; Anguiano, M; Villar, R [Consejo Superior de Investigaciones CientIficas, Instituto de FIsica Aplicada, C/Serrano 144, 28006-Madrid (Spain)

    2004-01-21

    In this paper, the specific absorption rate (SAR) in scaled human head models is analysed to study possible differences between SAR in the heads of adults and children and for assessment of compliance with the international safety guidelines, while using a mobile phone. The finite-difference time-domain method (FDTD) has been used for calculating SAR values for models of both children and adults, at 900 and 1800 MHz. Maximum 1 g averaged SAR (SAR{sub 1g}) and maximum 10 g averaged SAR (SAR{sub 10g}) have been calculated in adults and scaled head models for comparison and assessment of compliance with ANSI/IEEE and European guidelines. Results show that peak SAR{sub 1g} and peak SAR{sub 10g} all trend downwards with decreasing head size but as head size decreases, the percentage of energy absorbed in the brain increases. So, higher SAR in children's brains can be expected depending on whether the thickness of their skulls and surrounding tissues actually depends on age. The SAR in eyes of different sizes, as a critical organ, has also been studied and very similar distributions for the full size and the scaled models have been obtained. Standard limits can only be exceeded in the unpractical situation where the antenna is located at a very short distance in front of the eye.

  19. SAROTA: application of specific absorption rate (SAR) and over-the-air (OTA) data for the characterization of the real-life exposure due to mobile phones

    International Nuclear Information System (INIS)

    Monebhurrun, Vikass

    2013-01-01

    The RF exposure level of a mobile phone is quantified by the measurement of the specific absorption rate (SAR) under laboratory conditions. The SAR which is measured while the mobile phone is operated at maximum power level does not reflect the real-life exposure scenario since the mobile phone typically re-adjusts its power level and frequency depending on the quality of the communication link with the nearest base station. The choice of a low RF exposure device based on the comparison of the relative SAR values of mobile phones can be misleading. The real-life RF exposure also depends on the over-the-air (OTA) performance of the mobile phone. Taken independently, the two sets of data do not allow a straightforward comparison of the global RF performance amongst mobile phones. A unique and simple parameter denoted as the SAROTA index is proposed for the characterization of mobile phones with regard to both RF exposure and OTA performance. The SAROTA index provides the real-life exposure index of the mobile phone.

  20. Analysis of specific absorption rate and internal electric field in human biological tissues surrounding an air-core coil-type transcutaneous energy transmission transformer.

    Science.gov (United States)

    Shiba, Kenji; Zulkifli, Nur Elina Binti; Ishioka, Yuji

    2017-06-01

    In this study, we analyzed the internal electric field E and specific absorption rate (SAR) of human biological tissues surrounding an air-core coil transcutaneous energy transmission transformer. Using an electromagnetic simulator, we created a model of human biological tissues consisting of a dry skin, wet skin, fat, muscle, and cortical bone. A primary coil was placed on the surface of the skin, and a secondary coil was located subcutaneously inside the body. The E and SAR values for the model representing a 34-year-old male subject were analyzed using electrical frequencies of 0.3-1.5 MHz. The transmitting power was 15 W, and the load resistance was 38.4 Ω. The results showed that the E values were below the International Commission on Non-ionizing Radiation Protection (ICNIRP) limit for the general public exposure between the frequencies of 0.9 and 1.5 MHz, and SAR values were well below the limit prescribed by the ICNIRP for the general public exposure between the frequencies of 0.3 and 1.2 MHz.

  1. Proportion-corrected scaled voxel models for Japanese children and their application to the numerical dosimetry of specific absorption rate for frequencies from 30 MHz to 3 GHz

    International Nuclear Information System (INIS)

    Nagaoka, Tomoaki; Watanabe, Soichi; Kunieda, Etsuo

    2008-01-01

    The development of high-resolution anatomical voxel models of children is difficult given, inter alia, the ethical limitations on subjecting children to medical imaging. We instead used an existing voxel model of a Japanese adult and three-dimensional deformation to develop three voxel models that match the average body proportions of Japanese children at 3, 5 and 7 years old. The adult model was deformed to match the proportions of a child by using the measured dimensions of various body parts of children at 3, 5 and 7 years old and a free-form deformation technique. The three developed models represent average-size Japanese children of the respective ages. They consist of cubic voxels (2 mm on each side) and are segmented into 51 tissues and organs. We calculated the whole-body-averaged specific absorption rates (WBA-SARs) and tissue-averaged SARs for the child models for exposures to plane waves from 30 MHz to 3 GHz; these results were then compared with those for scaled down adult models. We also determined the incident electric-field strength required to produce the exposure equivalent to the ICNIRP basic restriction for general public exposure, i.e., a WBA-SAR of 0.08 W kg -1 .

  2. Tilt optimized flip uniformity (TOFU) RF pulse for uniform image contrast at low specific absorption rate levels in combination with a surface breast coil at 7 Tesla.

    Science.gov (United States)

    van Kalleveen, Irene M L; Boer, Vincent O; Luijten, Peter R; Klomp, Dennis W J

    2015-08-01

    Going to ultrahigh field MRI (e.g., 7 Tesla [T]), the nonuniformity of the B1+ field and the increased radiofrequency (RF) power deposition become challenging. While surface coils improve the power efficiency in B1+, its field remains nonuniform. In this work, an RF pulse was designed that uses the slab selection to compensate the inhomogeneous B1+ field of a surface coil without a substantial increase in specific absorption rate (SAR). A breast surface coil was used with a decaying B1+ field in the anterior-posterior direction of the human breast. Slab selective RF pulses were designed and compared with adiabatic and spokes RF pulses. Proof of principle was demonstrated with FFE and B1+ maps of the human breast. In vivo measurements obtained with the breast surface coil show that the tilt optimized flip uniformity (TOFU) RF pulses can improve the flip angle homogeneity by 31%, while the SAR will be lower compared with BIR-4 and spokes RF pulses. By applying TOFU RF pulses to the breast surface coil, we are able to compensate the inhomogeneous B1+ field, while keeping the SAR low. Therefore stronger T1 -weighting in FFE sequences can be obtained, while pulse durations can remain short, as shown in the human breast at 7T. © 2014 Wiley Periodicals, Inc.

  3. Folate absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Folate is the generic term given to numerous compounds of pteroic acid with glutamic acid. Knowledge of absorption is limited because of the complexities introduced by the variety of compounds and because of the inadequacy of investigational methods. Two assay methods are in use, namely microbiological and radioactive. Techniques used to study absorption include measurement of urinary excretion, serum concentration, faecal excretion, intestinal perfusion, and haematological response. It is probably necessary to test absorption of both pteroylmonoglutamic acid and one or more polyglutamates, and such tests would be facilitated by availability of synthesized compounds labelled with radioactive tracers at specifically selected sites. (author)

  4. FDTD calculations of specific energy absorption rate in a seated voxel model of the human body from 10 MHz to 3 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Findlay, R P; Dimbylow, P J [Health Protection Agency, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom)

    2006-05-07

    Finite-difference time-domain (FDTD) calculations have been performed to investigate the frequency dependence of the specific energy absorption rate (SAR) in a seated voxel model of the human body. The seated model was derived from NORMAN (NORmalized MAN), an anatomically realistic voxel phantom in the standing posture with arms to the side. Exposure conditions included both vertically and horizontally polarized plane wave electric fields between 10 MHz and 3 GHz. The resolution of the voxel model was 4 mm for frequencies up to 360 MHz and 2 mm for calculations in the higher frequency range. The reduction in voxel size permitted the calculation of SAR at these higher frequencies using the FDTD method. SAR values have been calculated for the seated adult phantom and scaled versions representing 10-, 5- and 1-year-old children under isolated and grounded conditions. These scaled models do not exactly reproduce the dimensions and anatomy of children, but represent good geometric information for a seated child. Results show that, when the field is vertically polarized, the sitting position causes a second, smaller resonance condition not seen in resonance curves for the phantom in the standing posture. This occurs at {approx}130 MHz for the adult model when grounded. Partial-body SAR calculations indicate that the upper and lower regions of the body have their own resonant frequency at {approx}120 MHz and {approx}160 MHz, respectively, when the grounded adult model is orientated in the sitting position. These combine to produce this second resonance peak in the whole-body averaged SAR values calculated. Two resonance peaks also occur for the sitting posture when the incident electric field is horizontally polarized. For the adult model, the peaks in the whole-body averaged SAR occur at {approx}180 and {approx}600 MHz. These peaks are due to resonance in the arms and feet, respectively. Layer absorption plots and colour images of SAR in individual voxels show the

  5. FDTD calculations of specific energy absorption rate in a seated voxel model of the human body from 10 MHz to 3 GHz

    International Nuclear Information System (INIS)

    Findlay, R P; Dimbylow, P J

    2006-01-01

    Finite-difference time-domain (FDTD) calculations have been performed to investigate the frequency dependence of the specific energy absorption rate (SAR) in a seated voxel model of the human body. The seated model was derived from NORMAN (NORmalized MAN), an anatomically realistic voxel phantom in the standing posture with arms to the side. Exposure conditions included both vertically and horizontally polarized plane wave electric fields between 10 MHz and 3 GHz. The resolution of the voxel model was 4 mm for frequencies up to 360 MHz and 2 mm for calculations in the higher frequency range. The reduction in voxel size permitted the calculation of SAR at these higher frequencies using the FDTD method. SAR values have been calculated for the seated adult phantom and scaled versions representing 10-, 5- and 1-year-old children under isolated and grounded conditions. These scaled models do not exactly reproduce the dimensions and anatomy of children, but represent good geometric information for a seated child. Results show that, when the field is vertically polarized, the sitting position causes a second, smaller resonance condition not seen in resonance curves for the phantom in the standing posture. This occurs at ∼130 MHz for the adult model when grounded. Partial-body SAR calculations indicate that the upper and lower regions of the body have their own resonant frequency at ∼120 MHz and ∼160 MHz, respectively, when the grounded adult model is orientated in the sitting position. These combine to produce this second resonance peak in the whole-body averaged SAR values calculated. Two resonance peaks also occur for the sitting posture when the incident electric field is horizontally polarized. For the adult model, the peaks in the whole-body averaged SAR occur at ∼180 and ∼600 MHz. These peaks are due to resonance in the arms and feet, respectively. Layer absorption plots and colour images of SAR in individual voxels show the specific regions in which the

  6. 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)

  7. α-Glucosidase inhibitor miglitol attenuates glucose fluctuation, heart rate variability and sympathetic activity in patients with type 2 diabetes and acute coronary syndrome: a multicenter randomized controlled (MACS) study.

    Science.gov (United States)

    Shimabukuro, Michio; Tanaka, Atsushi; Sata, Masataka; Dai, Kazuoki; Shibata, Yoshisato; Inoue, Yohei; Ikenaga, Hiroki; Kishimoto, Shinji; Ogasawara, Kozue; Takashima, Akira; Niki, Toshiyuki; Arasaki, Osamu; Oshiro, Koichi; Mori, Yutaka; Ishihara, Masaharu; Node, Koichi

    2017-07-06

    Little is known about clinical associations between glucose fluctuations including hypoglycemia, heart rate variability (HRV), and the activity of the sympathetic nervous system (SNS) in patients with acute phase of acute coronary syndrome (ACS). This pilot study aimed to evaluate the short-term effects of glucose fluctuations on HRV and SNS activity in type 2 diabetes mellitus (T2DM) patients with recent ACS. We also examined the effect of suppressing glucose fluctuations with miglitol on these variables. This prospective, randomized, open-label, blinded-endpoint, multicenter, parallel-group comparative study included 39 T2DM patients with recent ACS, who were randomly assigned to either a miglitol group (n = 19) or a control group (n = 20). After initial 24-h Holter electrocardiogram (ECG) (Day 1), miglitol was commenced and another 24-h Holter ECG (Day 2) was recorded. In addition, continuous glucose monitoring (CGM) was performed throughout the Holter ECG. Although frequent episodes of subclinical hypoglycemia (≤4.44 mmo/L) during CGM were observed on Day 1 in the both groups (35% of patients in the control group and 31% in the miglitol group), glucose fluctuations were decreased and the minimum glucose level was increased with substantial reduction in the episodes of subclinical hypoglycemia to 7.7% in the miglitol group on Day 2. Holter ECG showed that the mean and maximum heart rate and mean LF/HF were increased on Day 2 in the control group, and these increases were attenuated by miglitol. When divided 24-h time periods into day-time (0700-1800 h), night-time (1800-0000 h), and bed-time (0000-0700 h), we found increased SNS activity during day-time, increased maximum heart rate during night-time, and glucose fluctuations during bed-time, which were attenuated by miglitol treatment. In T2DM patients with recent ACS, glucose fluctuations with subclinical hypoglycemia were associated with alterations of HRV and SNS activity, which were mitigated by

  8. Blood pressure, body mass index, heart rate and levels of blood cholesterol and glucose of volunteers during National Heart Weeks, 1995-1997.

    Science.gov (United States)

    Khoo, K L; Tan, H; Liew, Y M; Sambhi, J S; Aljafri, A M; Hatijah, A

    2000-12-01

    The paper presents the results of a health screening programme conducted in 10 major centers in Malaysia--Kuala Lumpur, Penang, Ipoh, Johor Bahru, Alor Star, Kuala Terengganu, Malacca, Kota Bahru, Kuching and Kota Kinabalu during the National Heart Weeks, 1995-1997. There were 6,858 participants of both sexes aged between 6 years to 81 years old. The parameters involved in the screening programme were body mass index, blood pressure, heart rate, cholesterol and glucose. The following are the results of the study:- 1. The mean and standard deviation for the body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), total cholesterol (TC) and non fasting (random) blood glucose (GL) of the volunteers studied were 24.3 +/- 4.0 kg/m2, 128.3 +/- 21.1 mmHg, 79.6 +/- 11.9 mmHg, 77.2 +/- 12.1 bpm, 5.33 +/- 1.37 mmol/l and 5.11 +/- 1.97 mmol/l respectively. 2. There was a rising trend for BMI, SBP, DBP, TC and GL with age. The HR was higher in the younger age group of those below 20 years. Males tended to have higher mean values than females except for HR which was similar in both sexes. 3. The Malays, Chinese and Indians seemed to have closely similar mean values for SBP, DBP and HR but the Indians possessed the highest BMI (25.62 +/- 3.90 kg/m2), TC (5.61 +/- 1.48 mmol/l) and GL (5.41 +/- 2.43 mmol/l) among the three major ethnic groups. While the Ibans had highest TC (6.07 + 1.09 mmol/l), their GL level was the lowest (4.76 +/- 1.15 mmol/l). The Kadazans had the lowest TC level (4.94 +/- 1.39 mmol/l) among all the ethnic groups. 4. Among the participants screened, 31.9% were overweight (BMI > or = 25), 7.6% were obese (BMI > or = 30); 26.8% had raised SBP (> or = 140 mmHg) and 19.3% had raised DBP (> or = 90 mmHg); 13.6% of the participants had increased HR (> or = 90 bpm), 22% had raised TC (> or = 6.20 mmol/l) and 2% had raised GL (> or = 11.00 mmol/l). There was a higher prevalence for abnormal values with increasing age

  9. NLP modeling for the optimization of LiBr-H_2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    International Nuclear Information System (INIS)

    Mussati, Sergio F.; Gernaey, Krist V.; Morosuk, Tatiana; Mussati, Miguel C.

    2016-01-01

    Highlights: • A NLP model is used for simultaneous optimization of sizes and operating conditions. • Total exergy loss rate and transfer area are optimized as single objective functions. • Theoretical and practical bounds for cost optimization problems are computed. • A systematic solution strategy is proposed for total annual cost optimization. • Relevance of components is ranked by heat transfer area, exergy loss rate, and cost. - Abstract: Based on a nonlinear mathematical programming model, the sizes and operating conditions of the process units of single-effect absorption refrigeration systems operating with a LiBr–H_2O solution are optimized for a specified cooling capacity by minimizing three single objective functions: the total exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat transfer area between these bounds was also performed, allowing to see how the optimal distribution of the available total heat transfer area among the system components, as well as the operating conditions (stream temperature, pressure, composition, and mass flow rate) and heat loads, vary qualitatively and quantitatively with increasing available total heat transfer area. These optimization results allowed to find a “practical” value of the total heat transfer area, i.e. no benefits can be obtained by increasing the available total heat transfer area above this value since the minimal total exergy loss value cannot

  10. 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.

  11. Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling

    International Nuclear Information System (INIS)

    Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; Onishi, Teruo

    2014-01-01

    This study investigates the specific absorption rate (SAR) and the in situ electric field in anatomically based human models for the magnetic field from an inductive wireless power transfer system developed on the basis of the specifications of the wireless power consortium. The transfer system consists of two induction coils covered by magnetic sheets. Both the waiting and charging conditions are considered. The transfer frequency considered in this study is 140 kHz, which is within the range where the magneto-quasi-static approximation is valid. The SAR and in situ electric field in the chest and arm of the models are calculated by numerically solving the scalar potential finite difference equation. The electromagnetic modelling of the coils in the wireless power transfer system is verified by comparing the computed and measured magnetic field distributions. The results indicate that the peak value of the SAR averaged over a 10 g of tissue and that of the in situ electric field are 72 nW kg −1  and 91 mV m −1  for a transmitted power of 1 W, Consequently, the maximum allowable transmitted powers satisfying the exposure limits of the SAR (2 W kg −1 ) and the in situ electric field (18.9 V m −1 ) are found to be 28 MW and 43 kW. The computational results show that the in situ electric field in the chest is the most restrictive factor when compliance with the wireless power transfer system is evaluated according to international guidelines. (paper)

  12. Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling.

    Science.gov (United States)

    Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; Onishi, Teruo

    2014-07-21

    This study investigates the specific absorption rate (SAR) and the in situ electric field in anatomically based human models for the magnetic field from an inductive wireless power transfer system developed on the basis of the specifications of the wireless power consortium. The transfer system consists of two induction coils covered by magnetic sheets. Both the waiting and charging conditions are considered. The transfer frequency considered in this study is 140 kHz, which is within the range where the magneto-quasi-static approximation is valid. The SAR and in situ electric field in the chest and arm of the models are calculated by numerically solving the scalar potential finite difference equation. The electromagnetic modelling of the coils in the wireless power transfer system is verified by comparing the computed and measured magnetic field distributions. The results indicate that the peak value of the SAR averaged over a 10 g of tissue and that of the in situ electric field are 72 nW kg(-1) and 91 mV m(-1) for a transmitted power of 1 W, Consequently, the maximum allowable transmitted powers satisfying the exposure limits of the SAR (2 W kg(-1)) and the in situ electric field (18.9 V m(-1)) are found to be 28 MW and 43 kW. The computational results show that the in situ electric field in the chest is the most restrictive factor when compliance with the wireless power transfer system is evaluated according to international guidelines.

  13. Numerical analysis of specific absorption rate in the human head due to a 13.56 MHz RFID-based intra-ocular pressure measurement system

    International Nuclear Information System (INIS)

    Hirtl, Rene; Schmid, Gernot

    2013-01-01

    A modern wireless intra-ocular pressure monitoring system, based on 13.56 MHz inductively coupled data transmission, was dosimetrically analyzed with respect to the specific absorption rate (SAR) induced inside the head and the eye due to the electromagnetic field exposure caused by the reader antenna of the transmission system. The analysis was based on numerical finite difference time domain computations using a high resolution anatomical eye model integrated in a modern commercially available anatomical model of a male head. Three different reader antenna configurations, a 7-turn elliptic (30 mm × 50 mm) antenna at 12 mm distance from the eye, a flexible circular antenna (60 mm diameter, 8 turns on 2 mm substrate) directly attached to the skin, and a circular 7-turn antenna (30 mm diameter at 12 mm distance to the eye) were analyzed, respectively. Possible influences of the eye-lid status (closed or opened) and the transponder antenna contained in a contact lens directly attached to the eye were taken into account. The results clearly demonstrated that for typical reader antenna currents required for proper data transmission, the SAR values remain far below the limits for localized exposure of the head, as defined by the International Commission for Non-Ionizing Radiation Protection. Particularly the induced SAR inside the eye was found to be substantially (orders of magnitudes for typical reader antenna currents in the order of 1 A turn) below values which have been reported to be critical with respect to thermally induced adverse health effects in eye tissues. (note)

  14. Compressive strength and initial water absorption rate for cement brick containing high-density polyethylene (HDPE) as a substitutional material for sand

    Science.gov (United States)

    Ali, Noorwirdawati; Din, Norhasmiza; Sheikh Khalid, Faisal; Shahidan, Shahiron; Radziah Abdullah, Siti; Samad, Abdul Aziz Abdul; Mohamad, Noridah

    2017-11-01

    The rapid growth of today’s construction sector requires high amount of building materials. Bricks, known to have solid properties and easy to handle, which leads to the variety of materials added or replaced in its mixture. In this study, high density polyethylene (HDPE) was selected as the substitute materials in the making of bricks. The reason behind the use of HDPE is because of its recyclable properties and the recycling process that do not emit hazardous gases to the atmosphere. Other than that, the use of HDPE will help reducing the source of pollution by avoiding the millions of accumulated plastic waste in the disposal sites. Furthermore, the material has high endurance level and is weatherproof. This study was carried out on experimenting the substitute materials in the mixture of cement bricks, a component of building materials which is normally manufactured using the mixture of cement, sand and water, following a certain ratios, and left dried to produce blocks of bricks. A series of three different percentages of HDPE were used, which were 2.5%, 3.0% and 3.5%. Tests were done on the bricks, to study its compressive strength and the initial water absorption rate. Both tests were conducted on the seventh and 28th day. Based on the results acquired, for compressive strength tests on the 28th day, the use of 2.5% of HDPE shown values of 12.6 N/mm2 while the use of 3.0% of HDPE shown values of 12.5 N/mm2. Onto the next percentage, 3.5% of HDPE shown values of 12.5 N/mm2.

  15. The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz.

    Science.gov (United States)

    Hirata, Akimasa; Laakso, Ilkka; Oizumi, Takuya; Hanatani, Ryuto; Chan, Kwok Hung; Wiart, Joe

    2013-02-21

    According to the international safety guidelines/standard, the whole-body-averaged specific absorption rate (Poljak et al 2003 IEEE Trans. Electromagn. Compat. 45 141-5) and the peak spatial average SAR are used as metrics for human protection from whole-body and localized exposures, respectively. The IEEE standard (IEEE 2006 IEEE C95.1) indicates that the upper boundary frequency, over which the whole-body-averaged SAR is deemed to be the basic restriction, has been reduced from 6 to 3 GHz, because radio-wave energy is absorbed around the body surface when the frequency is increased. However, no quantitative discussion has been provided to support this description especially from the standpoint of temperature elevation. It is of interest to investigate the maximum temperature elevation in addition to the core temperature even for a whole-body exposure. In the present study, using anatomically based human models, we computed the SAR and the temperature elevation for a plane-wave exposure from 30 MHz to 6 GHz, taking into account the thermoregulatory response. As the primary result, we found that the ratio of the core temperature elevation to the whole-body-averaged SAR is almost frequency independent for frequencies below a few gigahertz; the ratio decreases above this frequency. At frequencies higher than a few gigahertz, core temperature elevation for the same whole-body averaged SAR becomes lower due to heat convection from the skin to air. This lower core temperature elevation is attributable to skin temperature elevation caused by the power absorption around the body surface. Then, core temperature elevation even for whole-body averaged SAR of 4 W kg(-1) with the duration of 1 h was at most 0.8 °C, which is smaller than a threshold considered in the safety guidelines/standard. Further, the peak 10 g averaged SAR is correlated with the maximum body temperature elevations without extremities and pinna over the frequencies considered. These findings

  16. A curve-fitting approach to estimate the arterial plasma input function for the assessment of glucose metabolic rate and response to treatment.

    Science.gov (United States)

    Vriens, Dennis; de Geus-Oei, Lioe-Fee; Oyen, Wim J G; Visser, Eric P

    2009-12-01

    For the quantification of dynamic (18)F-FDG PET studies, the arterial plasma time-activity concentration curve (APTAC) needs to be available. This can be obtained using serial sampling of arterial blood or an image-derived input function (IDIF). Arterial sampling is invasive and often not feasible in practice; IDIFs are biased because of partial-volume effects and cannot be used when no large arterial blood pool is in the field of view. We propose a mathematic function, consisting of an initial linear rising activity concentration followed by a triexponential decay, to describe the APTAC. This function was fitted to 80 oncologic patients and verified for 40 different oncologic patients by area-under-the-curve (AUC) comparison, Patlak glucose metabolic rate (MR(glc)) estimation, and therapy response monitoring (Delta MR(glc)). The proposed function was compared with the gold standard (serial arterial sampling) and the IDIF. To determine the free parameters of the function, plasma time-activity curves based on arterial samples in 80 patients were fitted after normalization for administered activity (AA) and initial distribution volume (iDV) of (18)F-FDG. The medians of these free parameters were used for the model. In 40 other patients (20 baseline and 20 follow-up dynamic (18)F-FDG PET scans), this model was validated. The population-based curve, individually calibrated by AA and iDV (APTAC(AA/iDV)), by 1 late arterial sample (APTAC(1 sample)), and by the individual IDIF (APTAC(IDIF)), was compared with the gold standard of serial arterial sampling (APTAC(sampled)) using the AUC. Additionally, these 3 methods of APTAC determination were evaluated with Patlak MR(glc) estimation and with Delta MR(glc) for therapy effects using serial sampling as the gold standard. Excellent individual fits to the function were derived with significantly different decay constants (P AUC from APTAC(AA/iDV), APTAC(1 sample), and APTAC(IDIF) with the gold standard (APTAC(sampled)) were 0

  17. Improved water and sodium absorption from oral rehydration solutions based on rice syrup in a rat model of osmotic diarrhea.

    Science.gov (United States)

    Wapnir, R A; Litov, R E; Zdanowicz, M M; Lifshitz, F

    1991-04-01

    Rice syrup solids, rice protein, and casein hydrolysate were added to experimental oral rehydration solutions in various combinations and tested in a rat intestinal perfusion system. Chronic osmotic diarrhea was induced in juvenile rats by supplying the cathartic agents, magnesium citrate and phenolphthalein, in their drinking water for 1 week. The experimental oral rehydration solutions were compared with standard oral rehydration solutions containing 20 gm/L or 30 gm/L of glucose and with each other to determine if there were significant differences in net water, sodium, or potassium absorption. An oral rehydration solution containing 30 gm/L of rice syrup solids had a net water absorption rate significantly higher than that of the standard 20 gm/L glucose-based oral rehydration solution (2.1 +/- 0.62 versus 1.5 +/- 0.48 microliters/[min x cm], p less than 0.05). Casein hydrolysate did not significantly affect net water absorption. However, combinations of 30 gm/L rice syrup solids and 5 gm/L casein hydrolysate significantly increased (p less than 0.05) net sodium and potassium absorption compared with the 20 gm/L glucose-based oral rehydration solution but not versus rice syrup solids alone. Oral rehydration solutions containing 30 gm/L rice syrup solids plus 5 gm/L rice protein, and 30 gm/L rice syrup solids plus 5 gm/L casein hydrolysate, had net water absorption rates significantly higher than the rate of a 30 gm/L glucose-based oral rehydration solution (2.5 +/- 0.36 and 2.4 +/- 0.38, respectively, versus 0.87 +/- 0.40 microliters/[min x cm], p less than 0.05). Rice protein and casein hydrolysate, however, did not significantly affect net water, sodium, or potassium absorption when added to rice protein glucose-based oral rehydration solutions. An inverse correlation between osmolality and net water absorption was observed (r = -0.653, p less than 0.02). The data suggest that substitution of rice syrup solids for glucose in oral rehydration solutions will

  18. Narrative absorption

    DEFF Research Database (Denmark)

    Narrative Absorption brings together research from the social sciences and Humanities to solve a number of mysteries: Most of us will have had those moments, of being totally absorbed in a book, a movie, or computer game. Typically we do not have any idea about how we ended up in such a state. No...

  19. 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...

  20. Direct electrochemistry of glucose oxidase and glucose biosensing on a hydroxyl fullerenes modified glassy carbon electrode.

    Science.gov (United States)

    Gao, Yun-Fei; Yang, Tian; Yang, Xiao-Lu; Zhang, Yu-Shuai; Xiao, Bao-Lin; Hong, Jun; Sheibani, Nader; Ghourchian, Hedayatollah; Hong, Tao; Moosavi-Movahedi, Ali Akbar

    2014-10-15

    Direct electrochemistry of glucose oxidase (GOD) was achieved when GOD-hydroxyl fullerenes (HFs) nano-complex was immobilized on a glassy carbon (GC) electrode and protected with a chitosan (Chit) membrane. The ultraviolet-visible absorption spectrometry (UV-vis), transmission electron microscopy (TEM), and circular dichroism spectropolarimeter (CD) methods were utilized for additional characterization of the GOD, GOD-HFs and Chit/GOD-HFs. Chit/HFs may preserve the secondary structure and catalytic properties of GOD. The cyclic voltammograms (CVs) of the modified GC electrode showed a pair of well-defined quasi-reversible redox peaks with the formal potential (E°') of 353 ± 2 mV versus Ag/AgCl at a scan rate of 0.05 V/s. The heterogeneous electron transfer constant (ks) was calculated to be 2.7 ± 0.2s(-1). The modified electrode response to glucose was linear in the concentrations ranging from 0.05 to 1.0mM, with a detection limit of 5 ± 1 μM. The apparent Michaelis-Menten constant (Km(app)) was 694 ± 8 μM. Thus, the modified electrode could be applied as a third generation biosensor for glucose with high sensitivity, selectivity and low detection limit. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Dynamic mechanical analysis and high strain-rate energy absorption characteristics of vertically aligned carbon nanotube reinforced woven fiber-glass composites

    Science.gov (United States)

    The dynamic mechanical behavior and energy absorption characteristics of nano-enhanced functionally graded composites, consisting of 3 layers of vertically aligned carbon nanotube (VACNT) forests grown on woven fiber-glass (FG) layer and embedded within 10 layers of woven FG, with polyester (PE) and...

  2. The Effect of Ankle, Knee and Hip Isokinetic Fatigue on Shock Absorption and Rate of Loading during Pair-leg Landing

    Directory of Open Access Journals (Sweden)

    Hamideh Khodaveisi

    2016-12-01

    Conclusion: Findings of this study indicate that the fatigue protocol using Isokinetic devices with uniform speed, increases muscle strength due to generating stress at all the joints, thereby, compensating the active and passive joints for shock absorption, and load distribution on the lower extremities. 

  3. Neutron resonance absorption theory

    International Nuclear Information System (INIS)

    Reuss, P.

    1991-11-01

    After some recalls on the physics of neutron resonance absorption during their slowing down, this paper presents the main features of the theoretical developments performed by the french school of reactor physics: the effective reaction rate method so called Livolant-Jeanpierre theory, the generalizations carried out by the author, and the probability table method [fr

  4. High pressure HC1 conversion of cellulose to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Antonoplis, Robert Alexander [Univ. of California, Berkeley, CA (United States); Blanch, Harvey W. [Univ. of California, Berkeley, CA (United States); Wilke, Charles R. [Univ. of California, Berkeley, CA (United States)

    1981-08-01

    The production of ethanol from glucose by means of fermentation represents a potential long-range alternative to oil for use as a transportation fuel. Today's rising oil prices and the dwindling world supply of oil have made other fuels, such as ethanol, attractive alternatives. It has been shown that automobiles can operate, with minor alterations, on a 10% ethanol-gasoline mixture popularly known as gasohol. Wood has long been known as a potential source of glucose. Glucose may be obtained from wood following acid hydrolysis. In this research, it was found that saturating wood particles with HCl gas under pressure was an effective pretreatment before subjecting the wood to dilute acid hydrolysis. The pretreatment is necessary because of the tight lattice structure of cellulose, which inhibits dilute acid hydrolysis. HCl gas makes the cellulose more susceptible to hydrolysis and the glucose yield is doubled when dilute acid hydrolysis is preceded by HCl saturation at high pressure. The saturation was most effectively performed in a fluidized bed reactor, with pure HCl gas fluidizing equal volumes of ground wood and inert particles. The fluidized bed effectively dissipated the large amount of heat released upon HCl absorption into the wood. Batch reaction times of one hour at 314.7 p.s.i.a. gave glucose yields of 80% and xylose yields of 95% after dilute acid hydrolysis. A non-catalytic gas-solid reaction model, with gas diffusing through the solid limiting the reaction rate, was found to describe the HCl-wood reaction in the fluidized bed. HCl was found to form a stable adduct with the lignin residue in the wood, in a ratio of 3.33 moles per mole of lignin monomer. This resulted in a loss of 0.1453 lb. of HCl per pound of wood. The adduct was broken upon the addition of water. A process design and economic evaluation for a plant to produce 214 tons per day of glucose from air-dried ground Populus tristi gave an estimated glucose cost of 15.14 cents per pound

  5. Correlation of hypoxic cell fraction with glucose metabolic rate in gliomas with 18F-Fluoromisonidazole (FMISO) and 18F- Fluorodeoxyglucose (FDG) positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Tauro, A.J.; Scott, A.M.; Hannah, A.; Pathmaraj, K.; Tochon-Danguy, H.; Sachinidis, J.I.; Chan, J.D.; Berlangieri, S.U.; Egan, G.F.; Fabinyi, G.; McKay, W.J.; Cher, L.M.; Austin and Repatriation Medical Centre, Heidelberg, VIC

    1998-01-01

    Full text: FDG-PET studies of brain tumours to measure tumour activity are well established, with regions of higher grade tumour utilising more glucose compared to lower grade tumour tissue and normal tissue. FDG uptake in tumour cells may reflect anaerobic glycolysis, but this has not been proven in- vivo. FMISO is a novel positron-emitting compound that has been shown to selectively identify hypoxic but viable tissue, which may contribute to chemoradiotherapy resistance in tumour cells. Studies correlating measurements of regional hypoxia and glucose activity within brain tumours prior to therapy may help gain further insight into the relationship between hypoxic tumour tissue and resistance to chemoradiotherapy. Three patients with newly diagnosed primary brain tumours have been prospectively studied with FMISO-PET, FDG-PET and MRI, prior to surgery. Each patient presented with a suspected primary brain glioma on MRI, which were all confirmed to be high grade glioma on subsequent histology at surgery FMISO-PET, FDG-PET and MRI images of all patients were co-registered to precisely identify the areas of metabolic activity within tumour and surrounding cortical tissue. All gliomas demonstrated areas of FMISO uptake, which corresponded to areas of maximal FDG uptake, indicating a correlation between hypoxic areas within tumour with areas of increased glucose metabolic activity. This supports the hypothesis that hypoxic areas within tumour tissue may be associated with increased FDG uptake, although whether hypoxia itself increases FDG uptake remains controversial. These correlative studies characterising areas of hypoxia and glucose activity should hopefully assist in future therapeutic manipulations to improve the outcome from treatment of primary brain tumours

  6. Absorptive products

    International Nuclear Information System (INIS)

    Assarsson, P.G.; King, P.A.

    1976-01-01

    Applications for hydrophile gels produced by the radiation induced cross-linking in aqueous solution of polyethylene oxide and starch, as described in Norwegian patent 133501 (INIS RN 281494), such as sanitary napkins (diapers) and sanitary towels, are discussed. The process itself is also discussed and results, expressed as the percentage of insoluble gel and its absorptive capacity for saline solution as functions of the ratio of polyethylene oxide to starch and the radiation dose, are presented. (JIW)

  7. 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

  8. 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.

  9. Glucose and fructose 6-phosphate cycle in humans

    International Nuclear Information System (INIS)

    Karlander, S.; Roovete, A.; Vranic, M.; Efendic, S.

    1986-01-01

    We have determined the rate of glucose cycling by comparing turnovers of [2- 3 H]- and [6- 3 H]glucose under basal conditions and during a glucose infusion. Moreover, the activity of the fructose 6-phosphate cycle was assessed by comparing [3- 3 H]- and [6- 3 H]glucose. The study included eight lean subjects with normal glucose tolerance. They participated in two randomly performed investigations. In one experiment [2- 3 H]- and [6- 3 H]glucose were given simultaneously, while in the other only [3- 3 H]glucose was given. The basal rate of glucose cycling was 0.32 +/- 0.08 mg X kg-1 X min-1 or 17% of basal glucose production (P less than 0.005). During glucose infusion the activity of endogenous glucose cycling did not change but since glucose production was suppressed it amounted to 130% of glucose production. The basal fructose 6-phosphate cycle could be detected only in three subjects and was suppressed during glucose infusion. In conclusion, the glucose cycle is active in healthy humans both in basal conditions and during moderate hyperglycemia. In some subjects, the fructose 6-phosphate cycle also appears to be active. Thus it is preferable to use [6- 3 H]glucose rather than [3- 3 H]glucose when measuring glucose production and particularly when assessing glucose cycle

  10. Estimation of liver glucose metabolism after refeeding

    International Nuclear Information System (INIS)

    Rognstad, R.

    1987-01-01

    Refeeding or infusing glucose to rats fasted for 24 hr or more causes rapid liver glycogen synthesis, the carbon source now considered to be largely from gluconeogenesis. While substrate cycling between plasma glucose and liver glucose-6P is known to occur, this cycling has apparently been ignored when calculations are made of % contribution of direct and indirect pathways to liver glycogen synthesis, or when hepatic glucose output is calculated from glucose turnover minus the glucose infusion rate. They show that, isotopically, an estimate of the fluxes of liver glucokinase and glucose-6-phosphatase is required to quantitate sources of carbon for liver glycogen synthesis, and to measure hepatic glucose output (or uptake). They propose a method to estimate these fluxes, involving a short infusion of a 14 C labelled gluconeogenic precursor plus (6T)glucose, with determination of isotopic yields in liver glycogen and total glucose. Given also the rate of liver glycogen synthesis, this procedure permits the estimation of net gluconeogenesis and hepatic glucose output or uptake. Also, in vitro evidence against the notion of a drastic zonation of liver carbohydrate metabolism is presented, e.g. raising the glucose concentration from 10 to 25 mM increases the 14 C yield from H 14 CO 3 - in lactate, with the increased pyruvate kinase flux and decreased gluconeogenesis occurring in the same cell type, not opposing pathways in different hepatocyte types (as has been postulated by some to occur in vivo after refeeding

  11. RNAi silenced Dd-grp94 (Dictyostelium discoideum glucose-regulated protein 94 kDa) cell lines in Dictyostelium exhibit marked reduction in growth rate and delay in development.

    Science.gov (United States)

    Baviskar, Sandhya N; Shields, Malcolm S

    2010-01-01

    Glucose-regulated 94 kDa protein (Grp94) is a resident of the endoplasmic reticulum (ER) of multicellular eukaryotes. It is a constitutively expressed protein that is overexpressed in certain abnormal conditions of the cell such as depletion of glucose and calcium, and low oxygen and pH. The protein is also implicated in diseased conditions like cancer and Alzheimer's disease. In this study, the consequences of downregulation of Grp94 were investigated at both unicellular and multicellular stages of Dictyostelium discoideum. Previous studies have shown the expression of Dd-Grp94 (Dictyostelium discoideum glucose-regulated 94 kDa protein) in wild-type cells varies during development, and overexpression of Dd-Grp94 leads to abnormal cell shape and inhibition of development (i.e., formation of fruiting bodies). Grp94 is a known calcium binding protein and an efficient calcium buffer. Therefore, in the present study we hypothesized that downregulation of Dd-Grp94 protein would affect Dictyostelium cell structure, growth, and development. We found that Dd-grp94 RNAi recombinants exhibited reduced growth rate, cell size, and a subtle change in cell motility compared to the parental cells. The recombinants also exhibited a delay in development and small fruiting bodies. These results establish that Dd-grp94 plays a crucial role in determining normal cell structure, growth and differentiation.

  12. Blood-Brain Glucose Transfer: Repression in Chronic Hyperglycemia

    Science.gov (United States)

    Gjedde, Albert; Crone, Christian

    1981-10-01

    Diabetic patients with increased plasma glucose concentrations may develop cerebral symptoms of hypoglycemia when their plasma glucose is rapidly lowered to normal concentrations. The symptoms may indicate insufficient transport of glucose from blood to brain. In rats with chronic hyperglycemia the maximum glucose transport capacity of the blood-brain barrier decreased from 400 to 290 micromoles per 100 grams per minute. When plasma glucose was lowered to normal values, the glucose transport rate into brain was 20 percent below normal. This suggests that repressive changes of the glucose transport mechanism occur in brain endothelial cells in response to increased plasma glucose.

  13. Glucose kinetics in infants of diabetic mothers

    International Nuclear Information System (INIS)

    Cowett, R.M.; Susa, J.B.; Giletti, B.; Oh, W.; Schwartz, R.

    1983-01-01

    Glucose kinetic studies were performed to define the glucose turnover rate with 78% enriched D-[U-13C] glucose by the prime constant infusion technique at less than or equal to 6 hours of age in nine infants of diabetic mothers (four insulin-dependent and five chemical diabetic patients) at term. Five normal infants were studied as control subjects. All infants received 0.9% saline intravenously during the study with the tracer. Fasting plasma glucose, insulin, and glucose13/12C ratios were measured during the steady state, and the glucose turnover rate was derived. The average plasma glucose concentration was similar during the steady state in the infants of the diabetic mothers and in the control infants, and the glucose turnover rate was not significantly different among the groups: 2.3 +/- 0.6 mg . kg-1 min-1 in infants of insulin-dependent diabetic patients; 2.4 +/- 0.4 mg . kg-1 min-1 in infants of chemical diabetic patients; and 3.2 +/- 0.3 mg . kg-1 min-1 in the control subjects. Good control of maternal diabetes evidenced by the normal maternal hemoglobin A1c and plasma glucose concentration at delivery and cord plasma glucose concentration resulted in glucose kinetic values in the infants of diabetic mothers that were indistinguishable from those of control subjects. The data further support the importance of good control of the diabetic state in the pregnant woman to minimize or prevent neonatal hypoglycemia

  14. Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers.

    Science.gov (United States)

    Müller, Mattea; Canfora, Emanuel E; Blaak, Ellen E

    2018-02-28

    Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit.

  15. OZONE ABSORPTION IN RAW WATERS

    Directory of Open Access Journals (Sweden)

    LJILJANA TAKIĆ

    2008-03-01

    Full Text Available The ozone absorption in raw water entering the main ozonization step at the Belgrade drinking water supply plant was investigated in a continuous stirred tank reactor (CSTR. A slow chemical reaction rate of dissolved ozone and pollutants present in raw water have been experimentally determined. The modified Hatta number was defined and calculated as a criterion which determines whether and to which extent the reactions of ozone and pollutants influence the rate of the pure physical ozone absorption.

  16. Coping with an exogenous glucose overload: glucose kinetics of rainbow trout during graded swimming.

    Science.gov (United States)

    Choi, Kevin; Weber, Jean-Michel

    2016-03-15

    This study examines how chronically hyperglycemic rainbow trout modulate glucose kinetics in response to graded exercise up to critical swimming speed (Ucrit), with or without exogenous glucose supply. Our goals were 1) to quantify the rates of hepatic glucose production (Ra glucose) and disposal (Rd glucose) during graded swimming, 2) to determine how exogenous glucose affects the changes in glucose fluxes caused by exercise, and 3) to establish whether exogenous glucose modifies Ucrit or the cost of transport. Results show that graded swimming causes no change in Ra and Rd glucose at speeds below 2.5 body lengths per second (BL/s), but that glucose fluxes may be stimulated at the highest speeds. Excellent glucoregulation is also achieved at all exercise intensities. When exogenous glucose is supplied during exercise, trout suppress hepatic production from 16.4 ± 1.6 to 4.1 ± 1.7 μmol·kg(-1)·min(-1) and boost glucose disposal to 40.1 ± 13 μmol·kg(-1)·min(-1). These responses limit the effects of exogenous glucose to a 2.5-fold increase in glycemia, whereas fish showing no modulation of fluxes would reach dangerous levels of 114 mM of blood glucose. Exogenous glucose reduces metabolic rate by 16% and, therefore, causes total cost of transport to decrease accordingly. High glucose availability does not improve Ucrit because the fish are unable to take advantage of this extra fuel during maximal exercise and rely on tissue glycogen instead. In conclusion, trout have a remarkable ability to adjust glucose fluxes that allows them to cope with the cumulative stresses of a glucose overload and graded exercise. Copyright © 2016 the American Physiological Society.

  17. 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

  18. Effects of taurine on plasma glucose concentration and active glucose transport in the small intestine.

    Science.gov (United States)

    Tsuchiya, Yo; Kawamata, Koichi

    2017-11-01

    Taurine lowers blood glucose levels and improves hyperglycemia. However, its effects on glucose transport in the small intestine have not been investigated. Here, we elucidated the effect of taurine on glucose absorption in the small intestine. In the oral glucose tolerance test, addition of 10 mmol/L taurine suppressed the increase in hepatic portal glucose concentrations. To investigate whether the suppressive effect of taurine occurs via down-regulation of active glucose transport in the small intestine, we performed an assay using the everted sac of the rat jejunum. Addition of taurine to the mucosal side of the jejunum suppressed active glucose transport via sodium-glucose cotransporter 1 (SGLT1). After elimination of chloride ions from the mucosal solution, taurine did not show suppressive effects on active glucose transport. These results suggest that taurine suppressed the increase in hepatic portal glucose concentrations via suppression of SGLT1 activity in the rat jejunum, depending on chloride ions. © 2017 Japanese Society of Animal Science.

  19. Effects of leucine supplemented diet on intestinal absorption in tumor bearing pregnant rats

    Directory of Open Access Journals (Sweden)

    de Mello Maria

    2002-04-01

    Full Text Available Abstract Background It is known that amino acid oxidation is increased in tumor-bearing rat muscles and that leucine is an important ketogenic amino acid that provides energy to the skeletal muscle. Methods To evaluate the effects of a leucine supplemented diet on the intestinal absorption alterations produced by Walker 256, growing pregnant rats were distributed into six groups. Three pregnant groups received a normal protein diet (18% protein: pregnant (N, tumor-bearing (WN, pair-fed rats (Np. Three other pregnant groups were fed a diet supplemented with 3% leucine (15% protein plus 3% leucine: leucine (L, tumor-bearing (WL and pair-fed with leucine (Lp. Non pregnant rats (C, which received a normal protein diet, were used as a control group. After 20 days, the animals were submitted to intestinal perfusion to measure leucine, methionine and glucose absorption. Results Tumor-bearing pregnant rats showed impairment in food intake, body weight gain and muscle protein content, which were less accentuated in WL than in WN rats. These metabolic changes led to reduction in both fetal and tumor development. Leucine absorption slightly increased in WN group. In spite of having a significant decrease in leucine and methionine absorption compared to L, the WL group has shown a higher absorption rate of methionine than WN group, probably due to the ingestion of the leucine supplemented diet inducing this amino acid uptake. Glucose absorption was reduced in both tumor-bearing groups. Conclusions Leucine supplementation during pregnancy in tumor-bearing rats promoted high leucine absorption, increasing the availability of the amino acid for neoplasic cells and, mainly, for fetus and host utilization. This may have contributed to the better preservation of body weight gain, food intake and muscle protein observed in the supplemented rats in relation to the non-supplemented ones.

  20. Effects of leucine supplemented diet on intestinal absorption in tumor bearing pregnant rats

    International Nuclear Information System (INIS)

    Ventrucci, Gislaine; Mello, Maria Alice Roston de; Gomes-Marcondes, Maria Cristina Cintra

    2002-01-01

    It is known that amino acid oxidation is increased in tumor-bearing rat muscles and that leucine is an important ketogenic amino acid that provides energy to the skeletal muscle. To evaluate the effects of a leucine supplemented diet on the intestinal absorption alterations produced by Walker 256, growing pregnant rats were distributed into six groups. Three pregnant groups received a normal protein diet (18% protein): pregnant (N), tumor-bearing (WN), pair-fed rats (Np). Three other pregnant groups were fed a diet supplemented with 3% leucine (15% protein plus 3% leucine): leucine (L), tumor-bearing (WL) and pair-fed with leucine (Lp). Non pregnant rats (C), which received a normal protein diet, were used as a control group. After 20 days, the animals were submitted to intestinal perfusion to measure leucine, methionine and glucose absorption. Tumor-bearing pregnant rats showed impairment in food intake, body weight gain and muscle protein content, which were less accentuated in WL than in WN rats. These metabolic changes led to reduction in both fetal and tumor development. Leucine absorption slightly increased in WN group. In spite of having a significant decrease in leucine and methionine absorption compared to L, the WL group has shown a higher absorption rate of methionine than WN group, probably due to the ingestion of the leucine supplemented diet inducing this amino acid uptake. Glucose absorption was reduced in both tumor-bearing groups. Leucine supplementation during pregnancy in tumor-bearing rats promoted high leucine absorption, increasing the availability of the amino acid for neoplasic cells and, mainly, for fetus and host utilization. This may have contributed to the better preservation of body weight gain, food intake and muscle protein observed in the supplemented rats in relation to the non-supplemented ones

  1. Glucose turnover, gluconeogenesis from glycerol, and estimation of net glucose cycling in cancer patients

    International Nuclear Information System (INIS)

    Lundholm, K.; Edstroem, S.; Karlberg, I.; Ekman, L.; Schersten, T.

    1982-01-01

    A double isotope method was used in patients with progressive malignancy and in control patients to measure: glucose turnover, conversion rate of carbon skeleton of glycerol into glucose, and the interorgan cycling of glucose carbons (Cori-cycle plus alanine-glucose cycle). [U- 14 C]glycerol and [6- 3 H]glucose were given intravenously as a single dose injection. The time course of the specific radioactivities of [6- 3 H] and [U- 14 C]glucose was followed in blood. The pool size and the turnover rate of glucose were increased in the cancer group as compared with the control patients. The net recycling of glucose carbons was not increased in the cancer group, despite the increased turnover of glucose. The alterations in the metabolism of glucose did not correlate with the plasma levels of insulin or thyroid hormones (T4, T3, rT3) neither in the entire cancer group nor in those cancer patients who were repeatedly investigated at different intervals of time. The turnover rate of glucose in the cancer patients correlated inversely to their body weight index. The gluconeogenesis rate, given as the fractional conversion rate of the injected radioactive dose of [ 14 C]glycerol, or as mol glucose . kg body weight-1 . day-1, was increased in the cancer group, but still contributed only 3% of the glucose turnover rate in both cancer and control patients. We conclude that an increased gluconeogenesis from glycerol is not significant in terms of energy expenditure in patients with progressive malignancy, as has previously been concluded for the gluconeogenesis from alanine. It seems that increased turnover of glucose may contribute to inappropriately high energy expenditure in cancer patients

  2. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast.

    Science.gov (United States)

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF.

  3. Effect of different glucose supply conditions on neuronal energy metabolism

    OpenAIRE

    Zheng, Hongwen; Wang, Rubin; Qu, Jingyi

    2016-01-01

    The glucose-excited neurons in brain can sense blood glucose levels and reflect different firing states, which are mainly associated with regulation of blood glucose and energy demand in the brain. In this paper, a new model of glucose-excited neuron in hypothalamus is proposed. The firing properties and energy consumption of this type of neuron under conditions of different glucose levels are simulated and analyzed. The results show that the firing rate and firing duration of the neuron both...

  4. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana

    2016-01-01

    exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit...... and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat...... transfer area between these bounds was also performed, allowing to see how the optimal distribution of the available total heat transfer area among the system components, as well as the operating conditions (stream temperature, pressure, composition, and mass flow rate) and heat loads, vary qualitatively...

  5. Renal glucose metabolism in normal physiological conditions and in diabetes.

    Science.gov (United States)

    Alsahli, Mazen; Gerich, John E

    2017-11-01

    The kidney plays an important role in glucose homeostasis via gluconeogenesis, glucose utilization, and glucose reabsorption from the renal glomerular filtrate. After an overnight fast, 20-25% of glucose released into the circulation originates from the kidneys through gluconeogenesis. In this post-absorptive state, the kidneys utilize about 10% of all glucose utilized by the body. After glucose ingestion, renal gluconeogenesis increases and accounts for approximately 60% of endogenous glucose release in the postprandial period. Each day, the kidneys filter approximately 180g of glucose and virtually all of this is reabsorbed into the circulation. Hormones (most importantly insulin and catecholamines), substrates, enzymes, and glucose transporters are some of the various factors influencing the kidney's role. Patients with type 2 diabetes have an increased renal glucose uptake and release in the fasting and the post-prandial states. Additionally, glucosuria in these patients does not occur at plasma glucose levels that would normally produce glucosuria in healthy individuals. The major abnormality of renal glucose metabolism in type 1 diabetes appears to be impaired renal glucose release during hypoglycemia. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. State of insulin self-association does not affect its absorption from the pulmonary route.

    Science.gov (United States)

    Hussain, Alamdar; Ahsan, Fakhrul

    2005-06-01

    This study is designed to compare and contrast the pulmonary absorption profiles of monomeric and hexameric insulin in the presence or absence of ethylene diamine tetraacetic acid (EDTA) or n-tetradecyl-beta-d-maltoside (TDM). The pulmonary absorption of two forms of insulin was studied by monitoring the changes in plasma insulin and glucose levels after intratracheal administration of monomeric or hexameric insulin into anesthetized rodents. EDTA or TDM was added to the formulation in order to evaluate if either of these agents has effects on the rate and extent of pulmonary absorption of monomeric and hexameric insulin. The biochemical changes that may occur after acute administration of TDM-based formulation have also been investigated by estimating lung injury markers in bronchoalveolar lavage fluid. A dose-dependent increase in the plasma insulin and decrease in plasma glucose levels was observed when increasing concentrations of hexameric or monomeric insulin were administered via the pulmonary route. Pulmonary administration of monomeric and hexameric insulin produced comparable absorption profiles in the presence or absence of EDTA or TDM. The bronchoalveolar lavage fluid analysis did not show differences in the levels of injury markers produced in TDM-treated rats and that produced in saline-treated rats, indicating no evidence for adverse effects of TDM in these short-term studies. Overall, in terms of rapidity of action and efficacy to reduce blood sugar, monomeric insulin did not provide advantages over hexameric insulin when administered via the pulmonary route.

  7. A simple and fast method for assessment of the nitrogen–phosphorus–potassium rating of fertilizers using high-resolution continuum source atomic and molecular absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bechlin, Marcos André; Fortunato, Felipe Manfroi; Moutinho da Silva, Ricardo; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta, E-mail: anchieta@iq.unesp.br

    2014-11-01

    The determination of N, P, and K in fertilizers by high-resolution continuum source flame atomic and molecular absorption spectrometry is proposed. Under optimized conditions, measurements of the diatomic molecules NO and PO at 215.360 and 247.620 nm, respectively, and K using the wing of the alternative line at 404.722 nm allowed calibration curves to be constructed in the ranges 500–5000 mg L{sup −1} N (r = 0.9994), 100–2000 mg L{sup −1} P (r = 0.9946), and 100–2500 mg L{sup −1} K (r = 0.9995). Commercial fertilizers were analyzed by the proposed method and the concentrations of N, P, and K were found to be in agreement with those obtained by Kjeldahl, spectrophotometric, and flame atomic emission spectrometry methods, respectively, at a 95% confidence level (paired t-test). A phosphate rock certified reference material (CRM) was analyzed and the results for P and K were in agreement with the reference values. Recoveries from spiked CRM were in the ranges 97–105% (NO{sub 3}{sup −}-N), 95–103% (NH{sub 4}{sup +}-N), 93–103% (urea-N), 99–108% (P), and 99–102% (K). The relative standard deviations (n = 12) for N, P, and K were 6, 4, and 2%, respectively. - Highlights: • A single technique is proposed to analyze NPK fertilizer. • HR-CS FAAS is proposed for the first time for N, P and K determination in fertilizers. • The method employs the same sample preparation and dilution for the three analytes. • Addition of H{sub 2}O{sub 2} allows analysis of fertilizers with different nitrogen species. • Proposal provides advantages over traditional methods in terms of cost and time.

  8. A simple and fast method for assessment of the nitrogen–phosphorus–potassium rating of fertilizers using high-resolution continuum source atomic and molecular absorption spectrometry

    International Nuclear Information System (INIS)

    Bechlin, Marcos André; Fortunato, Felipe Manfroi; Moutinho da Silva, Ricardo; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta

    2014-01-01

    The determination of N, P, and K in fertilizers by high-resolution continuum source flame atomic and molecular absorption spectrometry is proposed. Under optimized conditions, measurements of the diatomic molecules NO and PO at 215.360 and 247.620 nm, respectively, and K using the wing of the alternative line at 404.722 nm allowed calibration curves to be constructed in the ranges 500–5000 mg L −1 N (r = 0.9994), 100–2000 mg L −1 P (r = 0.9946), and 100–2500 mg L −1 K (r = 0.9995). Commercial fertilizers were analyzed by the proposed method and the concentrations of N, P, and K were found to be in agreement with those obtained by Kjeldahl, spectrophotometric, and flame atomic emission spectrometry methods, respectively, at a 95% confidence level (paired t-test). A phosphate rock certified reference material (CRM) was analyzed and the results for P and K were in agreement with the reference values. Recoveries from spiked CRM were in the ranges 97–105% (NO 3 − -N), 95–103% (NH 4 + -N), 93–103% (urea-N), 99–108% (P), and 99–102% (K). The relative standard deviations (n = 12) for N, P, and K were 6, 4, and 2%, respectively. - Highlights: • A single technique is proposed to analyze NPK fertilizer. • HR-CS FAAS is proposed for the first time for N, P and K determination in fertilizers. • The method employs the same sample preparation and dilution for the three analytes. • Addition of H 2 O 2 allows analysis of fertilizers with different nitrogen species. • Proposal provides advantages over traditional methods in terms of cost and time

  9. Effect and Modeling of Glucose Inhibition and In Situ Glucose Removal During Enzymatic Hydrolysis of Pretreated Wheat Straw

    DEFF Research Database (Denmark)

    Andric, Pavle; Meyer, Anne S.; Jensen, Peter Arendt

    2010-01-01

    The enzymatic hydrolysis of lignocellulosic biomass is known to be product-inhibited by glucose. In this study, the effects on cellulolytic glucose yields of glucose inhibition and in situ glucose removal were examined and modeled during extended treatment of heat-pretreated wheat straw......, during 96 h of reaction. When glucose was removed by dialysis during the enzymatic hydrolysis, the cellulose conversion rates and glucose yields increased. In fact, with dialytic in situ glucose removal, the rate of enzyme-catalyzed glucose release during 48-72 h of reaction recovered from 20......-40% to become approximate to 70% of the rate recorded during 6-24 h of reaction. Although Michaelis-Menten kinetics do not suffice to model the kinetics of the complex multi-enzymatic degradation of cellulose, the data for the glucose inhibition were surprisingly well described by simple Michaelis...

  10. Investigating Seed Germination Indices and Absorption Rate of Sodium, Chloride, Calcium, and Potassium in Different Parts of Seedlings of Sweet Corn KSC 403 (Zea Mays L var. Saccharata Under Salinity Stress and Seed Priming

    Directory of Open Access Journals (Sweden)

    M. Nasrolah alhossini,

    2014-02-01

    Full Text Available To investigate the effects of different levels of seed priming on germination indices and nutrient absorption at early growth stages of sweet corn (Golden Kernel Hybrid a factorial experiment based on completely randomized design was conducted with three replications in 2011. The experiment consists of 6 levels of primings (seeds without priming, priming with tap water, priming with distilled water, priming with sodium chloride, potassium chloride, and hydrous calcium chloride and five levels of salinity (zero, 4, 8, 12 and 16 ds/m sodium chloride. The characteristics studied were germination percentage, germination rate, root and shoot length, fresh weight and dry weight of seedling, root to shoot ratio and determination of sodium, chloride, calcium, and potassium concentration in different parts of seedlings (stems, roots and seed. The results indicated that increasing salinity stress levels decreased all parameters measured. Priming seeds with hydrated calcium chloride responded to significantly to salinity stress better than other treatments. Results also showed that increasing concentration of sodium chloride salt, increased absorption rate of sodium but concentration of calcium and potassium were reduced. Because application of hydrous calcium chloride stimulates cell in using calcium under salinity conditions it leads to improved seedling growth parameters. To achieve a more accurate results slicing interaction effect of seed priming×salinity levels was performed. Hydrous calcium chloride treatments improved all traits under study except sodium and potassium concentration. This represents a better performance of seeds germination under salinity stress when seeds primed with hydrous calcium chloride.

  11. Using Glucose Tolerance Tests to Model Insulin Secretion and Clearance

    Directory of Open Access Journals (Sweden)

    Anthony Shannon

    2005-04-01

    Full Text Available The purpose of the studies described in this paper is to develop theoretically and to validate experimentally mathematical compartment models which can be used to predict plasma insulin levels in patients with diabetes mellitus (DM. In the case of Type 2 Diabetes Mellitus (T2DM, the C-peptide levels in the plasma were measured as part of routine glucose tolerance tests in order to estimate the prehepatic insulin secretion rates. In the case of Type 1 Diabetes Mellitus (T1DM, a radioactive labelled insulin was used to measure the absorption rate of insulin after a subcutaneous injection of insulin. Both models gave close fits between theoretical estimates and experimental data, and, unlike other models, it is not necessary to seed these models with initial estimates.

  12. Stellar Absorption Line Analysis of Local Star-forming Galaxies: The Relation between Stellar Mass, Metallicity, Dust Attenuation, and Star Formation Rate

    International Nuclear Information System (INIS)

    Jabran Zahid, H.; Kudritzki, Rolf-Peter; Ho, I-Ting; Conroy, Charlie; Andrews, Brett

    2017-01-01

    We analyze the optical continuum of star-forming galaxies in the Sloan Digital Sky Survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. We fit models calculated with star formation and chemical evolution histories that are derived empirically from multi-epoch observations of the stellar mass–star formation rate and the stellar mass–gas-phase metallicity relations, respectively. We also fit linear combinations of single-burst models with a range of metallicities and ages. Star formation and chemical evolution histories are unconstrained for these models. The stellar mass–stellar metallicity relations obtained from the two methods agree with the relation measured from individual supergiant stars in nearby galaxies. These relations are also consistent with the relation obtained from emission-line analysis of gas-phase metallicity after accounting for systematic offsets in the gas-phase metallicity. We measure dust attenuation of the stellar continuum and show that its dependence on stellar mass and star formation rate is consistent with previously reported results derived from nebular emission lines. However, stellar continuum attenuation is smaller than nebular emission line attenuation. The continuum-to-nebular attenuation ratio depends on stellar mass and is smaller in more massive galaxies. Our consistent analysis of stellar continuum and nebular emission lines paves the way for a comprehensive investigation of stellar metallicities of star-forming and quiescent galaxies.

  13. Stellar Absorption Line Analysis of Local Star-forming Galaxies: The Relation between Stellar Mass, Metallicity, Dust Attenuation, and Star Formation Rate

    Energy Technology Data Exchange (ETDEWEB)

    Jabran Zahid, H. [Smithsonian Astrophysical Observatory, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kudritzki, Rolf-Peter; Ho, I-Ting [University of Hawaii at Manoa, Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Conroy, Charlie [Department of Astronomy, Harvard University, Cambridge, MA, 02138 (United States); Andrews, Brett, E-mail: zahid@cfa.harvard.edu [PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260 (United States)

    2017-09-20

    We analyze the optical continuum of star-forming galaxies in the Sloan Digital Sky Survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. We fit models calculated with star formation and chemical evolution histories that are derived empirically from multi-epoch observations of the stellar mass–star formation rate and the stellar mass–gas-phase metallicity relations, respectively. We also fit linear combinations of single-burst models with a range of metallicities and ages. Star formation and chemical evolution histories are unconstrained for these models. The stellar mass–stellar metallicity relations obtained from the two methods agree with the relation measured from individual supergiant stars in nearby galaxies. These relations are also consistent with the relation obtained from emission-line analysis of gas-phase metallicity after accounting for systematic offsets in the gas-phase metallicity. We measure dust attenuation of the stellar continuum and show that its dependence on stellar mass and star formation rate is consistent with previously reported results derived from nebular emission lines. However, stellar continuum attenuation is smaller than nebular emission line attenuation. The continuum-to-nebular attenuation ratio depends on stellar mass and is smaller in more massive galaxies. Our consistent analysis of stellar continuum and nebular emission lines paves the way for a comprehensive investigation of stellar metallicities of star-forming and quiescent galaxies.

  14. The absorption effect of the Lα-line Supplement to the paper 'On the Correlation Between the Hα-line emission rate and the ablation rate of a hydrogen pellet in tokamak discharges' – Nuclear Fusion 24 (1984) 697

    DEFF Research Database (Denmark)

    Chang, C. T.; Thomsen, Kenneth

    1985-01-01

    Several assumptions made in a previous study of the correlation between the Hα-line emission rate and the ablation rate of a hydrogen pellet injected into a tokamak discharge showed that the emission layer of the ablatant as optically thin with respect to all levels of the principal quantum numbe...

  15. Glucose production during exercise in humans

    DEFF Research Database (Denmark)

    Bergeron, R; Kjaer, M; Simonsen, L

    1999-01-01

    at 50.4 +/- 1.5(SE)% maximal O(2) consumption, followed by 30 min at 69.0 +/- 2.2% maximal O(2) consumption. The splanchnic blood flow was estimated by continuous infusion of indocyanine green, and net splanchnic glucose output was calculated as the product of splanchnic blood flow and a-hv blood...... glucose concentration differences. Glucose appearance rate was determined by a primed, continuous infusion of [3-(3)H]glucose and was calculated by using formulas for a modified single compartment in non-steady state. Glucose production was similar whether determined by the a-hv balance technique......The present study compared the arteriohepatic venous (a-hv) balance technique and the tracer-dilution method for estimation of hepatic glucose production during both moderate and heavy exercise in humans. Eight healthy young men (aged 25 yr; range, 23-30 yr) performed semisupine cycling for 40 min...

  16. Solutes transport characteristics in peritoneal dialysis: variations in glucose and insulin serum levels.

    Science.gov (United States)

    da Silva, Dirceu R; Figueiredo, Ana E; Antonello, Ivan C; Poli de Figueiredo, Carlos E; d'Avila, Domingos O

    2008-01-01

    Differences in small solutes transport rate (SSTR) during peritoneal dialysis (PD) may affect water and solutes removal. Patients with high SSTR must rely on shorter dwell times and increased dialysate glucose concentrations to keep fluid balance. Glucose absorption during peritoneal dialysis (PD), besides affecting glucose and insulin metabolism, may induce weight gain. The study aimed at examining acute glucose and insulin serum level changes and other potential relationships in PD patients with diverse SSTR. This cross-sectional study used a modified peritoneal equilibration test (PET) that enrolled 34 prevalent PD patients. Zero, 15, 30, 60, 120, 180, and 240-minute glucose and insulin serum levels were measured. Insulin resistance index was assessed by the homeostasis model assessment (HOMA-IR) formula. SSTR categories were classified by quartiles of the four-hour dialysate/serum creatinine ratio (D(4)/P(Cr)). Demographic and clinical variables were evaluated, and the body mass index (BMI) was estimated. Correlations among variables of interest and categories of SSTR were explored. Glucose serum levels were significantly different at 15, 30, and 60 minutes between high and low SSTR categories (p = 0.014, 0.009, and 0.022). Increased BMI (25.5 +/- 5.1) and insulin resistance [HOMA-IR = 2.60 (1.40-4.23)] were evidenced overall. Very strong to moderate correlations between insulin levels along the PET and HOMA-IR (r = 0.973, 0.834, 0.766, 0.728, 0.843, 0.857, 0.882) and BMI (r = 0.562, 0.459, 0.417, 0.370, 0.508, 0.514, 0.483) were disclosed. CONCLUSIONS; Early glucose serum levels were associated with SSTR during a PET. Overweight or obesity and insulin resistance were prevalent. An association between insulin serum levels and BMI was demonstrated.

  17. Intestinal absorption of copper: influence of carbohydrates.

    Science.gov (United States)

    Wapnir, R A; Balkman, C

    1992-02-01

    Macronutrients can modulate the intestinal absorption of trace elements by binding the metal or altering mucosal function. We investigated whether certain simple and complex carbohydrates modify copper (Cu) absorption, using an in vivo perfusion technique in the rat. Corn syrup solids, which contain a mixture of glucose polymers of diverse length, added at either 20 or 50 mosm/kg enhanced Cu absorption from a 31.5 microM (2 mg/liter) Cu solution (128 +/- 11 and 130 +/- 11 pmol/min x cm, respectively, vs 101 +/- 4 pmol/min x cm, P less than 0.05, in the absence of carbohydrate). This was concomitant with a stimulation of net water absorption (1.05 +/- 0.08 and 0.84 +/- 0.08 microliter/min x cm, respectively, vs 0.63 +/- 0.02 microliter/min x cm with no carbohydrate, P less than 0.05). Glucose, fructose, lactose, or sucrose had no influence on Cu absorption, although they altered water exchanges, an effect attributable to a reduction of the outflow component of fluid recirculation. Low concentrations of lactose resulted in a greater accumulation of Cu in the intestinal mucosa (8.75 +/- 0.71 micrograms/g vs 5.77 +/- 0.68 micrograms/g for controls, P less than 0.05). Hence, solutes that moderately stimulate mucosa-to-serosa fluid influx in a progressive manner, such as glucose polymers, may contribute to functionally increase Cu absorption. Conversely, conditions which tend to reduce water inflow or increase water outflow across the small intestinal mucosa, as may occur with high lactose diets or in cases of chronic diarrhea, may have negative effects.

  18. Blood glucose and liver function in dogs administered a xylitol drinking water additive at zero, one and five times dosage rates

    Directory of Open Access Journals (Sweden)

    James M.G. Anthony

    2011-05-01

    Full Text Available A study was designed to determine the safety of a drinking water additive that reduces plaque and calculus in dogs, and contains xylitol as an active ingredient. The randomized, double-blind, placebo-controlled study was performed in 15 crossbred dogs that were randomly divided into three groups and had their drinking water treated for 14 days with either: i a commercial health care product (BreathaLyser Plus at the recommended dosage, ii an experimental health care product (BreathaLyser Plus containing five times the amount of xylitol, or iii a placebo of purified water with a colour additive. Results demonstrated that the continuous administration of a commercial, drinking water, oral health product containing xylitol, at one and five times the normal inclusion rate, does not cause hypoglycemia or alter liver function in dogs.

  19. A glucose oxidase-coupled DNAzyme sensor for glucose detection in tears and saliva.

    Science.gov (United States)

    Liu, Chengcheng; Sheng, Yongjie; Sun, Yanhong; Feng, Junkui; Wang, Shijin; Zhang, Jin; Xu, Jiacui; Jiang, Dazhi

    2015-08-15

    Biosensors have been widely investigated and utilized in a variety of fields ranging from environmental monitoring to clinical diagnostics. Glucose biosensors have triggered great interest and have been widely exploited since glucose determination is essential for diabetes diagnosis. In here, we designed a novel dual-enzyme biosensor composed of glucose oxidase (GOx) and pistol-like DNAzyme (PLDz) to detect glucose levels in tears and saliva. First, GOx, as a molecular recognition element, catalyzes the oxidation of glucose forming H2O2; then PLDz recognizes the produced H2O2 as a secondary signal and performs a self-cleavage reaction promoted by Mn(2+), Co(2+) and Cu(2+). Thus, detection of glucose could be realized by monitoring the cleavage rate of PLDz. The slope of the cleavage rate of PLDz versus glucose concentration curve was fitted with a Double Boltzmann equation, with a range of glucose from 100 nM to 10mM and a detection limit of 5 μM. We further applied the GOx-PLDz 1.0 biosensor for glucose detection in tears and saliva, glucose levels in which are 720±81 μM and 405±56 μM respectively. Therefore, the GOx-PLDz 1.0 biosensor is able to determine glucose levels in tears and saliva as a noninvasive glucose biosensor, which is important for diabetic patients with frequent/continuous glucose monitoring requirements. In addition, induction of DNAzyme provides a new approach in the development of glucose biosensors. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. A prospective analysis of {sup 18}F-FDG PET/CT in patients with uveal melanoma: comparison between metabolic rate of glucose (MRglu) and standardized uptake value (SUV) and correlations with histopathological features

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Maria Lucia; Mattoli, Maria Vittoria; Rufini, Vittoria; Giordano, Alessandro [Universita Cattolica del Sacro Cuore, Institute of Nuclear Medicine, Roma (Italy); Blasi, Maria Antonietta; Sammarco, Maria Grazia [Universita Cattolica del Sacro Cuore, Institute of Ophthalmology, Roma (Italy); Petrone, Gianluigi; Mule, Antonino [Universita Cattolica del Sacro Cuore, Department of Pathology, Roma (Italy); Indovina, Luca [Universita Cattolica del Sacro Cuore, Physics Unit, Roma (Italy)

    2013-10-15

    To evaluate whether standardized uptake value (SUV) and/or metabolic rate of glucose (MRglu) are different among epithelioid, mixed, and spindle cell uveal melanomas, as well as between low and high risk melanomas; to correlate ultrasonographic data and metabolic parameters with histopathological features; and to assess the role of {sup 18}F-FDG PET/CT for evaluating prognosis. Of 34 eligible patients prospectively enrolled with clinical suspicion of medium/large uveal melanoma, 26 (15 men, mean age 62.8 {+-} 11.8 years) were evaluated. All patients underwent metastatic work-up, 3-D dynamic brain and whole-body {sup 18}F-FDG PET/CT, and surgery. Of the 26 ocular lesions, 23 showed {sup 18}F-FDG uptake, with a sensitivity of 88 %. MRglu was significantly higher in the epithelioid cell melanomas than in the spindle cell melanomas, as well as in high-risk lesions than in low-risk lesions (p = 0.01, p = 0.02, respectively). SUV and MRglu were correlated with histopathological features while ultrasonographic data were not. MRglu is useful for distinguishing the different cell types in uveal melanoma, as well as high-risk from low-risk lesions, while SUV is not. MRglu provides a more accurate evaluation of glucose consumption, whereas SUV provides only an estimation. In addition, the metabolic parameters correlate with histopathological features, well also reflecting cellular behaviour in ocular malignancy. A longer follow-up is needed to assess the role of {sup 18}F-FDG in evaluating prognosis. (orig.)

  1. 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 ...

  2. 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 ...

  3. 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 ...

  4. 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- ...

  5. 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 ...

  6. 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 ...

  7. 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 ...

  8. 抗阻训练搭配补充脱氢表雄酮对中年女性葡萄糖吸收能力的影响%Influence of Resistive Exercise with Dehydroepiandrosterone on Glucose Absorption Ability on Middle-Aged Women

    Institute of Scientific and Technical Information of China (English)

    郭枫; 秦虎

    2017-01-01

    The aim of the research was to investigate the effect of resistance training combined with dehydroepiandrosterone supplementation on glucose absorption capacity and hormones in middle-aged women.This research selected the female with average age of (50.8±7.22) and all the subjects were performed with the maximal repetition test (RM) to determine the basal maximal strength (body composition,muscle strength,hormone,glucose area under curve and area under insulin curve) one week before the treatment.Subjects were divided into three groups,containing DHRA group (n=5;daily 50 mg DHEA supplementation),resistance training group (n=6;70% of RM) and resistance training plus DHEA group (n=8).Blood samples were collected at study beginning,after 3 days and 8 weeks to determine the body composition and muscular strength,the hormone response,glucose area under curve and insulin area under curve.It could be found that the sit-up ability obviously increased in resistance training group.The concentration of cortisol in training group significantly increased in previous 3 days during examination.However,the concentration of testosterone significantly increased in resistance training plus DHEA supplementation group compared with resistance training group,but in each group,the indicators of GAUC and IAUC were all lower than base value.Further more the indicators of resistance training plus DHEA group trended to be lower than those in resistance training group.The experimental period was 8 weeks.In the end,cortisol concentration of each group was significantly less than the baseline,GAUC of every group was significantly higher than that in third day of the experimental period,but there was no difference in IAUC.Therefore,the initial resistance training adding DHEA could increase the ability of glucose uptake.Although the effect of long-term exercise adding DHEA was not as obvious as that of early exercise with supplementation of DHEA,it trended to be better than the effect of

  9. Underestimation of glucose turnover corrected with high-performance liquid chromatography purification of [6-3H]glucose

    International Nuclear Information System (INIS)

    Schwenk, W.F.; Butler, P.C.; Haymond, M.W.; Rizza, R.A.

    1990-01-01

    We have recently reported that during infusion of commercially available [6-3H]glucose, a radioactive nonglucose contaminant may accumulate in plasma causing errors in the measurement of glucose turnover. To determine whether purification of this tracer by HPLC (high-performance liquid chromatography) before infusion would eliminate the contaminant in plasma and remove the underestimation of glucose turnover reported during hyperinsulinemia, four normal subjects each underwent two 5-h euglycemic clamps during infusion of insulin (1 mU.kg-1.min-1). Glucose turnover was measured with either commercially available [6-3H]glucose or with HPLC-purified [6-3H]glucose. HPLC analysis of samples from the clamps done with commercially available [6-3H]glucose showed that 9.7% of the infused tracer and 26% of the plasma glucose 3H radioactivity were contaminants. In contrast, no contaminant was observed in the plasma during infusion of HPLC-purified [6-3H]glucose. During the last hour of the clamp, mean glucose turnover using commercially available [6-3H]glucose was less (P less than 0.01) than the mean glucose infusion rate (7.6 +/- 0.3 vs. 10.5 +/- 0.3 mg.kg-1.min-1) yielding apparent negative (P less than 0.001) hepatic glucose release. In contrast, when HPLC-purified [6-3H]glucose was employed, glucose turnover equaled the glucose infusion rate (10.4 +/- 0.9 vs. 10.2 +/- 0.9 mg.kg-1.min-1) and hepatic glucose release was no longer negative. We conclude that removal of a tritiated nonglucose contaminant in [6-3H]glucose by HPLC yields correct estimations of glucose turnover at steady state

  10. [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.

  11. Absorption properties of identical atoms

    International Nuclear Information System (INIS)

    Sancho, Pedro

    2013-01-01

    Emission rates and other optical properties of multi-particle systems in collective and entangled states differ from those in product ones. We show the existence of similar effects in the absorption probabilities for (anti)symmetrized states of two identical atoms. The effects strongly depend on the overlapping between the atoms and differ for bosons and fermions. We propose a viable experimental verification of these ideas. -- Highlights: •The absorption rates of a pair of identical atoms in product and (anti)symmetrized states are different. •The modifications of the optical properties are essentially determined by the overlapping between the atoms. •The absorption properties differ, in some cases, for bosons and fermions

  12. 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 ...

  13. 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 ...

  14. 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%.

  15. Effects of 2-Deoxy-D-Glucose on Metabolic Status, Proliferative Capacity and Growth Rate of FSall Tumor: Observations made by In Vivo 31P-Nuclear Magnetic Resonance Spectroscopy and Flow Cytometry

    International Nuclear Information System (INIS)

    Chang, Hye Sook; Choi, Eun Kyung; Cho, Jeong Gill; Lim, Tae Hwan; Lee, Tae Keun; Yi, Yun; Cho, Young Joo; Kim, Gon Sup

    1991-01-01

    The effect of 2-deoxy-d-glucose (2-DDG) on C 3 H mouse fibrosarcoma (FSall) was studied. Metabolic status, especially for energy metabolism, was studied using in vivo 31 P-MRS, proliferative capacity was observed on flow cytometry (FC) and growth rate was measured after transplantation of 106 viable tumor cells in the dorsum of foot of C 3 Hf/Sed mice. One gram of 2-DDG per kg of body weight was injected intraperitoneally on 12th day of implantation. Average tumor size on 12th day of implantation was 250mm 3 . Growth rate of FSall tumor was measured by tumor doubling time between tumor age 5-12 days was 0.84 days with slope 0.828 and tumor doubling time between tumor age 13-28 days was 3.2 days with slope 0.218 in control group. After 2-DDG injection, tumor doubling time was elongated to 5.1 days with slope 0.136. The effect of 2-DDG studied in vivo 31 P-MRS suggested that the increase of phosphomonoester (PME) and inorganic phosphate (Pi) by increasing size of tumor, slowed down after 2-DDG injection. Flow cytometry showed significantly increased S-phase and G 2 +M phase fraction suggesting increased proliferative capacity of tumor cells in the presence of 2-DDG. Authors observed an interesting effect 2-DDG on FSall tumor and attempt to utilize as an adjunct for radiotherapy

  16. Glucose Absorption by the Bacillary Band of Trichuris muris

    DEFF Research Database (Denmark)

    Hansen, Tina Vicky Alstrup; Hansen, Michael; Nejsum, Peter

    2016-01-01

    Background A common characteristic of Trichuris spp. infections in humans and animals is the variable but low efficacy of single-dose benzimidazoles currently used in mass drug administration programmes against human trichuriasis. The bacillary band, a specialised morphological structure of Trich......Background A common characteristic of Trichuris spp. infections in humans and animals is the variable but low efficacy of single-dose benzimidazoles currently used in mass drug administration programmes against human trichuriasis. The bacillary band, a specialised morphological structure...

  17. Glucose enhancement of memory depends on initial thirst.

    Science.gov (United States)

    Scholey, Andrew B; Sünram-Lea, Sandra I; Greer, Joanna; Elliott, Jade; Kennedy, David O

    2009-12-01

    This double-blind, placebo-controlled study examined the influence of appetitive state on glucose enhancement of memory. Participants rated their mood, hunger and thirst, then consumed a 25 g glucose drink or a matched placebo 20 min prior to a verbal memory task. There was a double dissociation when the effects of thirst ratings and drink on subsequent memory performance were considered. Those who were initially less thirsty recalled significantly more words following glucose than placebo; those who were more thirsty recalled significantly fewer words after glucose than placebo. Glucose enhancement of memory may therefore critically depend on participants' initial thirst.

  18. 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

  19. Modified starch enhances absorption and accelerates recovery in experimental diarrhea in rats.

    Science.gov (United States)

    Wingertzahn, M A; Teichberg, S; Wapnir, R A

    1999-03-01

    Rice gruels have been used as home remedies to treat dehydration associated with diarrheal illness in developing countries. These preparations have produced conflicting results, most likely due to the heterogeneity of starch used. We investigated whether the modified tapioca starch, Textra (TX), at 5.0 or 10.0 g/L added to a 90 mmol/L Na+-111 mmol glucose oral rehydration solution (ORS) enhanced water and electrolyte absorption in two models of diarrhea. To induce a secretory state (model A), the jejunum of juvenile rats was perfused with 10 mmol/L theophylline (THEO) under anesthesia and then perfused with the solutions indicated above. To produce chronic osmotic-secretory diarrhea (model B), rats had a magnesium citrate-phenolphthalein solution as the sole fluid source for 1 wk, and then were perfused as the THEO-treated rats. Water, electrolyte, and glucose absorption were measured during both perfusions. As an extension of the perfusion studies, we compared how fast rats recovered from chronic osmotic diarrhea by offering them either water, ORS, or ORS containing 5.0 g/L TX along with solid food. Recovery rate markers were measured after 24 h and included weight gain, food and fluid intake, and stool output. In model A, addition of 5.0 g/L TX to ORS reversed Na+ secretion and improved net water as well as K+ and glucose absorption, compared with THEO-treated rats perfused with ORS without TX. In model B, addition of TX to ORS increased water, Na+, K+, and glucose absorption, compared with rats perfused without TX. Increasing TX from 5.0 to 10.0 g/L had no additional benefit. In recovery experiments, animals with free access to ORS with TX had significantly greater weight gain and decreased stool output compared with animals recovering with water or ORS without TX. Our experiments suggest that TX may be a useful additive to standard ORS to promote fluid and electrolyte absorption and may provide additional energy without increasing ORS osmotic load.

  20. D-xylose absorption

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  1. The effects of consuming carbohydrate-electrolyte beverages on gastric emptying and fluid absorption during and following exercise.

    Science.gov (United States)

    Murray, R

    1987-01-01

    A variety of beverages formulated to provide fluid, carbohydrates, and electrolytes during and following exercise are commercially available. Such 'sport drinks' commonly contain 4 to 8% carbohydrate (as glucose, fructose, sucrose or maltodextrins) and small amounts of electrolytes (most often sodium, potassium, and chloride). The efficacy of consuming such beverages has been questioned primarily because of concern that beverage carbohydrate content may inhibit gastric emptying rate and fluid absorption during exercise, thereby jeopardizing physiological homeostasis and impairing exercise performance. Gastric motor activity, and consequently gastric emptying rate, is governed by neural and humoral feedback provided by receptors found in the gastric musculature and proximal small intestine. Gastric emptying rate may be influenced by a variety of factors including, but not limited to, the caloric content, volume, osmolality, temperature, and pH of the ingested fluid, diurnal and interindividual variation, metabolic state (rest/exercise), and the ambient temperature. The caloric content of the ingested fluid appears to be the most important variable governing gastric emptying rate, providing a mean caloric efflux from the stomach of 2.0 to 2.5 kcal/min for ingested fluid volumes less than 400 ml. At rest, gastric emptying is inhibited by solutions containing calories in a manner independent of the nutrient source (i.e. carbohydrate, fat or protein). Consequently, plain water is known to empty from the stomachs of resting subjects at rates faster than solutions containing calories. Gastric emptying is increasingly inhibited as the caloric content of the ingested fluid increases. During moderate exercise (less than 75% VO2max), gastric emptying occurs at a rate similar to that during rest; more intense exercise appears to inhibit gastric emptying. When fluids are consumed at regular intervals throughout prolonged exercise (greater than 2 hours), postexercise aspiration

  2. 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...

  3. Paracellular absorption: a bat breaks the mammal paradigm.

    Directory of Open Access Journals (Sweden)

    Enrique Caviedes-Vidal

    Full Text Available Bats tend to have less intestinal tissue than comparably sized nonflying mammals. The corresponding reduction in intestinal volume and hence mass of digesta carried is advantageous because the costs of flight increase with load carried and because take-off and maneuverability are diminished at heavier masses. Water soluble compounds, such as glucose and amino acids, are absorbed in the small intestine mainly via two pathways, the transporter-mediated transcellular and the passive, paracellular pathways. Using the microchiropteran bat Artibeus literatus (mean mass 80.6+/-3.7 g, we tested the predictions that absorption of water-soluble compounds that are not actively transported would be extensive as a compensatory mechanism for relatively less intestinal tissue, and would decline with increasing molecular mass in accord with sieve-like paracellular absorption. Using a standard pharmacokinetic technique, we fed, or injected intraperitoneally the metabolically inert carbohydrates L-rhamnose (molecular mass = 164 Da and cellobiose (molecular mass = 342 Da which are absorbed only by paracellular transport, and 3-O-methyl-D-glucose (3OMD-glucose which is absorbed via both mediated (active and paracellular transport. As predicted, the bioavailability of paracellular probes declined with increasing molecular mass (rhamnose, 90+/-11%; cellobiose, 10+/-3%, n = 8 and was significantly higher in bats than has been reported for laboratory rats and other mammals. In addition, absorption of 3OMD-glucose was high (96+/-11%. We estimated that the bats rely on passive, paracellular absorption for more than 70% of their total glucose absorption, much more than in non-flying mammals. Although possibly compensating for less intestinal tissue, a high intestinal permeability that permits passive absorption might be less selective than a carrier-mediated system for nutrient absorption and might permit toxins to be absorbed from plant and animal material in the

  4. Cimetidine absorption in humans during sucralfate coadministration.

    OpenAIRE

    D'Angio, R; Mayersohn, M; Conrad, K A; Bliss, M

    1986-01-01

    Cimetidine absorption after a single 300 mg oral dose was evaluated in six normal subjects in the absence or presence of sucralfate. Sucralfate was ingested four times a day for 2 days prior to and for two additional doses on the day of cimetidine ingestion. Sucralfate coadministration had no statistically significant influence on the rate or extent of cimetidine absorption.

  5. Absorption and excretion tests

    International Nuclear Information System (INIS)

    Berberich, R.

    1988-01-01

    The absorption and excretion of radiopharmaceuticals is still of interest in diagnostic investigations of nuclear medicine. In this paper the most common methods of measuring absorption and excretion are described. The performance of the different tests and their standard values are discussed. More over the basic possibilities of measuring absorption and excretion including the needed measurement equipments are presented. (orig.) [de

  6. Duodenal Ca2+ absorption is not stimulated by calcitriol during early postnatal development of pigs.

    Science.gov (United States)

    Schroeder, B; Dahl, M R; Breves, G

    1998-08-01

    The role of calcitriol in stimulating intestinal active Ca2+ absorption during postnatal life was studied in newborn, suckling, and weaned control (Con) piglets and piglets suffering from inherited calcitriol deficiency (Def piglets). In addition, a group of Def piglets was treated with vitamin D3 (Def-D3 piglets), which normalized plasma calcitriol levels. Regardless of age, duodenal calbindin-D9k concentrations ranged between 1,839 and 2,846 microg/g mucosa in Con piglets, between 821 and 1,219 microg/g mucosa in Def piglets, and between 2,960 and 3,692 microg/g mucosa in Def-D3 animals. In weaned animals, active Ca2+ absorption as calculated from in vitro 45Ca2+ flux rate measurements in Ussing chambers could be related to calbindin-D9k levels. Thus active Ca2+ absorption was completely absent in Def animals but was reconstituted in Def-D3 animals. In contrast, in newborn Def piglets active Ca2+ absorption functioned normally despite the low plasma calcitriol and mucosal calbindin-D9k levels and could not be affected by treatment with vitamin D3. Similar results were obtained from suckling Def piglets. The microtubule-disrupting agent colchicine caused significant inhibition of transepithelial net Ca2+ absorption in duodenal epithelia from newborn piglets without exerting an effect in suckling and weaned animals. Colchicine had no effect on Ca2+ uptake across the brush border membrane of mucosal enterocytes or on glucose-dependent electrogenic net ion flux rates in duodenal preparations from newborn Con piglets. In conclusion, our findings reveal intestinal active Ca2+ absorption during early postnatal life of pigs that involves calcitriol-independent mechanisms and that may include intact microtubule actions.

  7. 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...

  8. 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

  9. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Recker, R.R.

    1985-01-01

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  10. 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 ...

  11. 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...

  12. An anatomically realistic whole-body pregnant-woman model and specific absorption rates for pregnant-woman exposure to electromagnetic plane waves from 10 MHz to 2 GHz

    International Nuclear Information System (INIS)

    Nagaoka, Tomoaki; Togashi, Toshihiro; Saito, Kazuyuki; Takahashi, Masaharu; Ito, Koichi; Watanabe, Soichi

    2007-01-01

    The numerical dosimetry of pregnant women is an important issue in electromagnetic-field safety. However, an anatomically realistic whole-body pregnant-woman model for electromagnetic dosimetry has not been developed. Therefore, we have developed a high-resolution whole-body model of pregnant women. A new fetus model including inherent tissues of pregnant women was constructed on the basis of abdominal magnetic resonance imaging data of a 26-week-pregnant woman. The whole-body pregnant-woman model was developed by combining the fetus model and a nonpregnant-woman model that was developed previously. The developed model consists of about 7 million cubical voxels of 2 mm size and is segmented into 56 tissues and organs. This pregnant-woman model is the first completely anatomically realistic voxel model that includes a realistic fetus model and enables a numerical simulation of electromagnetic dosimetry up to the gigahertz band. In this paper, we also present the basic specific absorption rate characteristics of the pregnant-woman model exposed to vertically and horizontally polarized electromagnetic waves from 10 MHz to 2 GHz

  13. Calculations of B1 Distribution, Specific Energy Absorption Rate, and Intrinsic Signal-to-Noise Ratio for a Body-Size Birdcage Coil Loaded with Different Human Subjects at 64 and 128 MHz.

    Science.gov (United States)

    Liu, W; Collins, C M; Smith, M B

    2005-03-01

    A numerical model of a female body is developed to study the effects of different body types with different coil drive methods on radio-frequency magnetic ( B 1 ) field distribution, specific energy absorption rate (SAR), and intrinsic signal-to-noise ratio (ISNR) for a body-size birdcage coil at 64 and 128 MHz. The coil is loaded with either a larger, more muscular male body model (subject 1) or a newly developed female body model (subject 2), and driven with two-port (quadrature), four-port, or many (ideal) sources. Loading the coil with subject 1 results in significantly less homogeneous B 1 field, higher SAR, and lower ISNR than those for subject 2 at both frequencies. This dependence of MR performance and safety measures on body type indicates a need for a variety of numerical models representative of a diverse population for future calculations. The different drive methods result in similar B 1 field patterns, SAR, and ISNR in all cases.

  14. Robust time-shifted spoke pulse design in the presence of large B0 variations with simultaneous reduction of through-plane dephasing, B1+ effects, and the specific absorption rate using parallel transmission.

    Science.gov (United States)

    Guérin, Bastien; Stockmann, Jason P; Baboli, Mehran; Torrado-Carvajal, Angel; Stenger, Andrew V; Wald, Lawrence L

    2016-08-01

    To design parallel transmission spokes pulses with time-shifted profiles for joint mitigation of intensity variations due to B1+ effects, signal loss due to through-plane dephasing, and the specific absorption rate (SAR) at 7T. We derived a slice-averaged small tip angle (SA-STA) approximation of the magnetization signal at echo time that depends on the B1+ transmit profiles, the through-slice B0 gradient and the amplitude and time-shifts of the spoke waveforms. We minimize a magnitude least-squares objective based on this signal equation using a fast interior-point approach with analytical expressions of the Jacobian and Hessian. Our algorithm runs in less than three minutes for the design of two-spoke pulses subject to hundreds of local SAR constraints. On a B0/B1+ head phantom, joint optimization of the channel-dependent time-shifts and spoke amplitudes allowed signal recovery in high-B0 regions at no increase of SAR. Although the method creates uniform magnetization profiles (ie, uniform intensity), the flip angle varies across the image, which makes it ill-suited to T1-weighted applications. The SA-STA approach presented in this study is best suited to T2*-weighted applications with long echo times that require signal recovery around high B0 regions. Magn Reson Med 76:540-554, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  15. The kinetics of glucose production from rice straw by Aspergillus niger

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-03

    Jun 3, 2008 ... The concentration and rate of glucose production was observed to depend on pretreatment of ... cerning reaction rate parameters for rice straw hydrolysis. The generation of such ... The experiment and glucose analysis was ...

  16. Plasma glucagon and glucose recovery after hypoglycemia

    DEFF Research Database (Denmark)

    Hilsted, J; Frandsen, Henrik Lund; Holst, Janett

    1991-01-01

    ) and of isolated alpha-adrenergic blockade on hormonal responses to hypoglycemia and on blood glucose recovery after hypoglycemia in healthy subjects. Neither of the pharmacological blockades had any significant effects on plasma glucagon responses to hypoglycemia nor had they any effect on the rate of blood...... glucose recovery after hypoglycemia. We conclude that the autonomic nervous system has no major influence on the glucagon response to hypoglycemia in healthy man. Changes in autonomic nervous activity are not essential for blood glucose recovery after hypoglycemia in healthy man....

  17. 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...

  18. 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.

  19. Mechanism-based population modelling for assessment of L-cell function based on total GLP-1 response following an oral glucose tolerance test

    DEFF Research Database (Denmark)

    Møller, Jonas B.; Jusko, William J.; Gao, Wei

    2011-01-01

    was to build a mechanism-based population model that describes the time course of total GLP-1 and provides indices for capability of secretion in each subject. The goal was thus to model the secretion of GLP-1, and not its effect on insulin production. Single 75 g doses of glucose were administered orally......GLP-1 is an insulinotropic hormone that synergistically with glucose gives rise to an increased insulin response. Its secretion is increased following a meal and it is thus of interest to describe the secretion of this hormone following an oral glucose tolerance test (OGTT). The aim of this study....... The individual estimates of absorption rate constants were used in the model for GLP-1 secretion. Estimation of parameters was performed using the FOCE method with interaction implemented in NONMEM VI. The final transit/indirect-response model obtained for GLP-1 production following an OGTT included two...

  20. A study of glucose handling by Buddhist monks.

    Science.gov (United States)

    Aung, T; Myint, H; Thein, M

    1988-04-01

    Fourteen Buddhist monks and comparable male subjects were studied in relation to their handling of glucose after a meal (consisting of 1190 kcal, 29 g protein, 21 g fat and 221 g carbohydrate) and afterwards subjected to an oral glucose tolerance test (oGTT). The time course of blood glucose levels after the meal indicated that the monks had enhanced absorption and utilization of glucose. The monks were also found to have increased tolerance to glucose on oGTT. In addition the mean total serum cholesterol level in the monks (157.2 +/- 5.53 mg/dl) was found to be significantly higher than that of the control subjects (117.4 +/- 2.85 mg/dl).

  1. Accuracy of flash glucose monitoring and continuous glucose monitoring technologies: Implications for clinical practice.

    Science.gov (United States)

    Ajjan, Ramzi A; Cummings, Michael H; Jennings, Peter; Leelarathna, Lalantha; Rayman, Gerry; Wilmot, Emma G

    2018-02-01

    Continuous glucose monitoring and flash glucose monitoring technologies measure glucose in the interstitial fluid and are increasingly used in diabetes care. Their accuracy, key to effective glycaemic management, is usually measured using the mean absolute relative difference of the interstitial fluid sensor compared to reference blood glucose readings. However, mean absolute relative difference is not standardised and has limitations. This review aims to provide a consensus opinion on assessing accuracy of interstitial fluid glucose sensing technologies. Mean absolute relative difference is influenced by glucose distribution and rate of change; hence, we express caution on the reliability of comparing mean absolute relative difference data from different study systems and conditions. We also review the pitfalls associated with mean absolute relative difference at different glucose levels and explore additional ways of assessing accuracy of interstitial fluid devices. Importantly, much data indicate that current practice of assessing accuracy of different systems based on individualised mean absolute relative difference results has limitations, which have potential clinical implications. Healthcare professionals must understand the factors that influence mean absolute relative difference as a metric for accuracy and look at additional assessments, such as consensus error grid analysis, when evaluating continuous glucose monitoring and flash glucose monitoring systems in diabetes care. This in turn will ensure that management decisions based on interstitial fluid sensor data are both effective and safe.

  2. Galactic absorption line coronae

    International Nuclear Information System (INIS)

    Bregman, J.N.

    1981-01-01

    We have investigated whether gaseous coronae around galaxies rise to the absorption systems seen in quasar spectra. In our model, gas originally located in the disk is heated to the million degree range and rises to surround the galaxy; the gas remains bound to the galaxy. Optically thin radiative cooling drives a thermal instability in the hot gas which causes cool clouds (T 4 K) to condense out of the corona. These clouds, which follow ballistic trajectories back to the disk, are the absorption sites. A two-dimensional hydrodynamic code with radiative cooling was used to study the dynamics and thermodynamics of the corona as well as the position rate at which clouds form. Coupled to the code is a galaxy with two mass components, a disk (approx.10 11 M/sub sun/) and a dark halo (approx.10 12 M/sub sun/). In a model where the temperature at the base of the corona (in the disk) is 3 x 10 6 K, absorbing gas of column density NL> or approx. =10 18 cm 2 extends radially to 100 kpc (face-on orientation) and vertically to 60 Kpc (edge-on orientation). The total mass of gas required here (coronal plus cloud gas) is 1.4 x 10 10 M/sub sun/, while the minimum supernova heating rate is one supernova per 27 years. In two other models (base coronal temperatures of 0.50 x 10 6 K and 1 x 10 6 K), coronal gas rises from an extended gaseous disk (in the previous model, the gas comes from a typical gaseous disk approximately 15 kpc in extent). Here, column densities of 10 19 cm -2 out to a radius of 70 kpc (face-on orientation) are achieved with a total gas mass of 1.7 x 10 9 M/sub direct-product/ and 2.0 x 10 9 M/sub sun/ and minimum heating rates of approximately one supernova per 170 years and one supernova per 60 years

  3. Early evaluation of cerebral metabolic rate of glucose (CMRglu) with {sup 18}F-FDG PET/CT and clinical assessment in idiopathic normal pressure hydrocephalus (INPH) patients before and after ventricular shunt placement: preliminary experience

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Maria Lucia; Lavalle, Mariadea; Leccisotti, Lucia; Giordano, Alessandro [Universita Cattolica del Sacro Cuore, Institute of Nuclear Medicine, Rome (Italy); Mangiola, Annunziato; De Bonis, Pasquale; Anile, Carmelo [Universita Cattolica del Sacro Cuore, Institute of Neurosurgery, Rome (Italy); Indovina, Luca [Universita Cattolica del Sacro Cuore, Institute of Physics, Rome (Italy); Marra, Camillo [Universita Cattolica del Sacro Cuore, Institute of Neurology, Rome (Italy); Pelliccioni, Armando [Istituto Nazionale per l' Assicurazione contro gli Infortuni sul Lavoro (INAIL), Rome (Italy)

    2012-02-15

    We evaluated the relationships between the cerebral metabolic rate of glucose (CMRglu) measured by dynamic {sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and the clinical and neuropsychological assessment before and after the surgical procedure in idiopathic normal pressure hydrocephalus (INPH) patients. Eleven selected INPH patients underwent clinical assessment (modified Rankin scale, Krauss scale, Larsson categorization system and Stein-Langfitt scale), cognitive evaluation (Mini-Mental State Examination, MMSE) and dynamic {sup 18}F-FDG PET/CT scan 3 days before and 1 week after ventricular shunt placement. After shunting, the global CMRglu significantly increased (2.95 {+-} 0.44 vs 4.38 {+-} 0.68, p = 10{sup -7}) in all INPH patients with a mean percentage value of 48.7%. After shunting, no significant change was found in the Evans ratio whereas a significant decrease in all clinical scale scores was observed. Only a slight reduction in the MMSE was found. After shunting, a significant correlation between the global CMRglu value and clinical assessment was found (R {sup 2} = 0.75, p = 0.024); indeed all clinical scale scores varied (decreasing) and the CMRglu value also varied (increasing) in all INPH patients. Our preliminary data show that changes in the CMRglu are promptly reversible after surgery and that there is a relationship between the early metabolic changes and clinical symptoms, independently from the simultaneous changes in the ventricular size. The remarkable and prompt improvement in the global CMRglu and in symptoms may also have important implications for the current concept of ''neuronal plasticity'' and for the cells' reactivity in order to recover their metabolic function. (orig.)

  4. Early evaluation of cerebral metabolic rate of glucose (CMRglu) with 18F-FDG PET/CT and clinical assessment in idiopathic normal pressure hydrocephalus (INPH) patients before and after ventricular shunt placement: preliminary experience

    International Nuclear Information System (INIS)

    Calcagni, Maria Lucia; Lavalle, Mariadea; Leccisotti, Lucia; Giordano, Alessandro; Mangiola, Annunziato; De Bonis, Pasquale; Anile, Carmelo; Indovina, Luca; Marra, Camillo; Pelliccioni, Armando

    2012-01-01

    We evaluated the relationships between the cerebral metabolic rate of glucose (CMRglu) measured by dynamic 18 F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and the clinical and neuropsychological assessment before and after the surgical procedure in idiopathic normal pressure hydrocephalus (INPH) patients. Eleven selected INPH patients underwent clinical assessment (modified Rankin scale, Krauss scale, Larsson categorization system and Stein-Langfitt scale), cognitive evaluation (Mini-Mental State Examination, MMSE) and dynamic 18 F-FDG PET/CT scan 3 days before and 1 week after ventricular shunt placement. After shunting, the global CMRglu significantly increased (2.95 ± 0.44 vs 4.38 ± 0.68, p = 10 -7 ) in all INPH patients with a mean percentage value of 48.7%. After shunting, no significant change was found in the Evans ratio whereas a significant decrease in all clinical scale scores was observed. Only a slight reduction in the MMSE was found. After shunting, a significant correlation between the global CMRglu value and clinical assessment was found (R 2 = 0.75, p = 0.024); indeed all clinical scale scores varied (decreasing) and the CMRglu value also varied (increasing) in all INPH patients. Our preliminary data show that changes in the CMRglu are promptly reversible after surgery and that there is a relationship between the early metabolic changes and clinical symptoms, independently from the simultaneous changes in the ventricular size. The remarkable and prompt improvement in the global CMRglu and in symptoms may also have important implications for the current concept of ''neuronal plasticity'' and for the cells' reactivity in order to recover their metabolic function. (orig.)

  5. 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 ...

  6. 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...

  7. 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? ...

  8. 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.

  9. Absorption heat pumps

    International Nuclear Information System (INIS)

    Formigoni, C.

    1998-01-01

    A brief description of the difference between a compression and an absorption heat pump is made, and the reasons why absorption systems have spread lately are given. Studies and projects recently started in the field of absorption heat pumps, as well as criteria usually followed in project development are described. An outline (performance targets, basic components) of a project on a water/air absorption heat pump, running on natural gas or LPG, is given. The project was developed by the Robur Group as an evolution of a water absorption refrigerator operating with a water/ammonia solution, which has been on the market for a long time and recently innovated. Finally, a list of the main energy and cost advantages deriving from the use of absorption heat pumps is made [it

  10. 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...

  11. 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 ...

  12. Predictive models of glucose control: roles for glucose-sensing neurones

    Science.gov (United States)

    Kosse, C.; Gonzalez, A.; Burdakov, D.

    2018-01-01

    The brain can be viewed as a sophisticated control module for stabilizing blood glucose. A review of classical behavioural evidence indicates that central circuits add predictive (feedforward/anticipatory) control to the reactive (feedback/compensatory) control by peripheral organs. The brain/cephalic control is constructed and engaged, via associative learning, by sensory cues predicting energy intake or expenditure (e.g. sight, smell, taste, sound). This allows rapidly measurable sensory information (rather than slowly generated internal feedback signals, e.g. digested nutrients) to control food selection, glucose supply for fight-or-flight responses or preparedness for digestion/absorption. Predictive control is therefore useful for preventing large glucose fluctuations. We review emerging roles in predictive control of two classes of widely projecting hypothalamic neurones, orexin/hypocretin (ORX) and melanin-concentrating hormone (MCH) cells. Evidence is cited that ORX neurones (i) are activated by sensory cues (e.g. taste, sound), (ii) drive hepatic production, and muscle uptake, of glucose, via sympathetic nerves, (iii) stimulate wakefulness and exploration via global brain projections and (iv) are glucose-inhibited. MCH neurones are (i) glucose-excited, (ii) innervate learning and reward centres to promote synaptic plasticity, learning and memory and (iii) are critical for learning associations useful for predictive control (e.g. using taste to predict nutrient value of food). This evidence is unified into a model for predictive glucose control. During associative learning, inputs from some glucose-excited neurones may promote connections between the ‘fast’ senses and reward circuits, constructing neural shortcuts for efficient action selection. In turn, glucose-inhibited neurones may engage locomotion/exploration and coordinate the required fuel supply. Feedback inhibition of the latter neurones by glucose would ensure that glucose fluxes they

  13. Predictive models of glucose control: roles for glucose-sensing neurones.

    Science.gov (United States)

    Kosse, C; Gonzalez, A; Burdakov, D

    2015-01-01

    The brain can be viewed as a sophisticated control module for stabilizing blood glucose. A review of classical behavioural evidence indicates that central circuits add predictive (feedforward/anticipatory) control to the reactive (feedback/compensatory) control by peripheral organs. The brain/cephalic control is constructed and engaged, via associative learning, by sensory cues predicting energy intake or expenditure (e.g. sight, smell, taste, sound). This allows rapidly measurable sensory information (rather than slowly generated internal feedback signals, e.g. digested nutrients) to control food selection, glucose supply for fight-or-flight responses or preparedness for digestion/absorption. Predictive control is therefore useful for preventing large glucose fluctuations. We review emerging roles in predictive control of two classes of widely projecting hypothalamic neurones, orexin/hypocretin (ORX) and melanin-concentrating hormone (MCH) cells. Evidence is cited that ORX neurones (i) are activated by sensory cues (e.g. taste, sound), (ii) drive hepatic production, and muscle uptake, of glucose, via sympathetic nerves, (iii) stimulate wakefulness and exploration via global brain projections and (iv) are glucose-inhibited. MCH neurones are (i) glucose-excited, (ii) innervate learning and reward centres to promote synaptic plasticity, learning and memory and (iii) are critical for learning associations useful for predictive control (e.g. using taste to predict nutrient value of food). This evidence is unified into a model for predictive glucose control. During associative learning, inputs from some glucose-excited neurones may promote connections between the 'fast' senses and reward circuits, constructing neural shortcuts for efficient action selection. In turn, glucose-inhibited neurones may engage locomotion/exploration and coordinate the required fuel supply. Feedback inhibition of the latter neurones by glucose would ensure that glucose fluxes they stimulate

  14. Estimation of endogenous glucose production during hyperinsulinemic-euglycemic glucose clamps. Comparison of unlabeled and labeled exogenous glucose infusates

    International Nuclear Information System (INIS)

    Finegood, D.T.; Bergman, R.N.; Vranic, M.

    1987-01-01

    Tracer methodology has been applied extensively to the estimation of endogenous glucose production (Ra) during euglycemic glucose clamps. The accuracy of this approach has been questioned due to the observation of significantly negative estimates for Ra when insulin levels are high. We performed hyperinsulinemic (300 microU/ml)-euglycemic glucose clamps for 180 min in normal dogs and compared the standard approach, an unlabeled exogenous glucose infusate (cold GINF protocol, n = 12), to a new approach in which a tracer (D-[3- 3 H]glucose) was added to the exogenous glucose used for clamping (hot GINF protocol, n = 10). Plasma glucose, insulin and glucagon concentrations, and glucose infusion rates were similar for the two protocols. Plasma glucose specific activity was 20 +/- 1% of basal (at 120-180 min) in the cold GINF studies, and 44 +/- 3 to 187 +/- 5% of basal in the hot GINF studies. With the one-compartment, fixed pool volume model of Steele, Ra for the cold GINF studies was -2.4 +/- 0.7 mg X min-1 X kg-1 at 25 min and remained significantly negative until 110 min (P less than .05). For the hot GINF studies, Ra was never significantly less than zero (P greater than .05) and was greater than in the cold GINF studies at 20-90 min (P less than .05). There was substantially less between-(78%) and within- (40%) experiment variation for the hot GINF studies compared with the cold GINF studies. An alternate approach (regression method) to the application of the one-compartment model, which allows for a variable and estimable effective distribution volume, yielded Ra estimates that were suppressed 60-100% from basal

  15. Characterization of the intravenous glucose tolerance test and the combined glucose-insulin test in donkeys.

    Science.gov (United States)

    Mendoza, F J; Aguilera-Aguilera, R; Gonzalez-De Cara, C A; Toribio, R E; Estepa, J C; Perez-Ecija, A

    2015-12-01

    Glucose-insulin dynamic challenges such as the intravenous glucose tolerance test (IVGTT) and combined glucose-insulin test (CGIT) have not been described in donkeys. The objectives of this study were (1) to characterize the IVGTT and CGIT in healthy adult donkeys, and (2) to establish normal glucose-insulin proxies. Sixteen donkeys were used and body morphometric variables obtained each. For the IVGTT, glucose (300 mg/kg) was given IV. For the CGIT, glucose (150 mg/kg) followed by recombinant insulin (0.1 IU/kg) were administered IV. Blood samples for glucose and insulin determinations were collected over 300 min. In the IVGTT the positive phase lasted 160.9 ± 13.3 min, glucose concentration peaked at 323.1 ± 9.2 mg/dL and declined at a rate of 1.28 ± 0.15 mg/dL/min. The glucose area under the curve (AUC) was 21.4 ± 1.9 × 10(3) mg/dL/min and the insulin AUC was 7.2 ± 0.9 × 10(3) µIU/mL/min. The positive phase of the CGIT curve lasted 44 ± 3 min, with a glucose clearance rate of 2.01 ± 0.18 mg/dL/min. The negative phase lasted 255.9 ± 3 min, decreasing glucose concentration at rate of -0.63 ± 0.06 mg/dL/min, and reaching a nadir (33.1 ± 3.6 mg/dL) at 118.3 ± 6.3 min. The glucose and insulin AUC values were 15.2 ± 0.9 × 10(3) mg/dL/min and 13.2 ± 0.9 × 10(3) µIU/mL/min. This is the first study characterizing CGIT and IVGTT, and glucose-insulin proxies in healthy adult donkeys. Distinct glucose dynamics, when compared with horses, support the use of species-specific protocols to assess endocrine function. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Water absorption characteristic of interlocking compressed earth brick units

    Science.gov (United States)

    Bakar, B. H. Abu; Saari, S.; Surip, N. A.

    2017-10-01

    This study aims to investigate the water absorption characteristic of interlocking compressed earth brick (ICEB) units. Apart from compressive strength, water absorption is an important property in masonry. This property can affect the quality of the brick itself and the bond strength between the brick and mortar in masonry structures and can result in reducing its strength properties. The units were tested for 24 h water absorption and 5 h boiling water absorption. A total of 170 ICEB units from four ICEB types underwent both tests. For the 24 h water absorption, the ICEB units were dried in the oven for 24 h and then cooled before being weighed. Thereafter, each brick was immersed in water for 24 h and weighed. The same specimens used for the 24 h water absorption test were re-used for the 5 h boiling water absorption test. After completing the 24 h water absorption test, the brick was boiled for 5-hours and weighed. The highest water absorption for the ICEBs in the 24-hour water absorption and 5 h boiling water absorption tests are 15.09% and 17.18%, respectively. The half brick has the highest water absorption (15.87%), whereas the beam brick has the lowest (13.20%). The water absorption of an ICEB unit is higher than that of normal bricks, although the water absorption of the former remains below the maximum rate of the brick water absorption (21%).

  17. Insulin secretion and cellular glucose metabolism after prolonged low-grade intralipid infusion in young men

    DEFF Research Database (Denmark)

    Jensen, Christine B; Storgaard, Heidi; Holst, Jens J

    2003-01-01

    We examined the simultaneous effects of a 24-h low-grade Intralipid infusion on peripheral glucose disposal, intracellular glucose partitioning and insulin secretion rates in twenty young men, by 2-step hyperinsulinemic euglycemic clamp [low insulin clamp (LI), 10 mU/m(2) x min; high insulin clamp...... Intralipid infusion. At LI, glucose oxidation decreased by 10%, whereas glucose disposal, glycolytic flux, glucose storage, and glucose production were not significantly altered. At HI, glucose disposal, and glucose oxidation decreased by 12% and 24%, respectively, during Intralipid infusion. Glycolytic flux......, glucose storage, and glucose production were unchanged. Insulin secretion rates increased in response to Intralipid infusion, but disposition indices (DI = insulin action.insulin secretion) were unchanged. In conclusion, a 24-h low-grade Intralipid infusion caused insulin resistance in the oxidative (but...

  18. Blood glucose measurement with multiple quantum cascade lasers using hollow-optical fiber-based ATR spectroscopy

    Science.gov (United States)

    Yoshioka, K.; Kino, S.; Matsuura, Y.

    2018-02-01

    For non-invasive blood glucose measurement, a measurement system based on mid-infrared ATR spectroscopy equipped with a combination of a QCL as a light source and a hollow-optical fiber as a beam delivery medium is developed. Firstly the measurement sensitivity of the system is evaluated by using glucose solutions and the result shows a significant correlation between optical absorbance and solution concentration. It is also confirmed that the system has a sensitivity that is enough for blood glucose measurement. Then optical absorption of human lips in the mid-infrared wavelength region is measured using a QCL with a wavenumber of 1080 cm-1 where human tissue exhibits strong absorption of glucose and its metabolites. As a result, the measured absorption follows the change of blood glucose well with a time delay of around 10 minutes and correlation factor between the absorbance and the blood glucose level is 0.42.

  19. Solar absorption surface panel

    Science.gov (United States)

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  20. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

  1. Zeeman atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Loos-Vollebregt, M.T.C. de.

    1980-01-01

    A new method of background correction in atomic absorption spectroscopy has recently been introduced, based on the Zeeman splitting of spectral lines in a magnetic field. A theoretical analysis of the background correction capability observed in such instruments is presented. A Zeeman atomic absorption spectrometer utilizing a 50 Hz sine wave modulated magnetic field is described. (Auth.)

  2. Effects of hyperglycemia on glucose production and utilization in humans. Measurement with [3H]-2-, [3H]-3-, and [14C]-6-glucose

    International Nuclear Information System (INIS)

    Bell, P.M.; Firth, R.G.; Rizza, R.A.

    1986-01-01

    Studies with tritiated isotopes of glucose have demonstrated that hyperglycemia per se stimulates glucose utilization and suppresses glucose production in humans. These conclusions rely on the assumption that tritiated glucose provides an accurate measure of glucose turnover. However, if in the presence of hyperglycemia the isotope either loses its label during futile cycling or retains its label during cycling through glycogen, then this assumption is not valid. To examine this question, glucose utilization and glucose production rates were measured in nine normal subjects with a simultaneous infusion of [ 3 H]-2-glucose, an isotope that may undergo futile cycling but does not cycle through glycogen; [ 14 C]-6-glucose, an isotope that may cycle through glycogen but does not futile cycle; and [ 3 H]-3-glucose, an isotope that can both undergo futile cycling and cycle through glycogen. In the postabsorptive state at plasma glucose concentration of 95 mg X dl-1, glucose turnover determined with [ 14 C]-6-glucose (2.3 +/- 0.1 mg X kg-1 X min-1) was greater than that determined with [3 3 H]glucose (2.1 +/- 0.1 mg X kg-1 X min-1, P = 0.002) and slightly less than that determined with [ 3 H]-2-glucose (2.7 +/- 0.2 mg X kg-1 X min-1, P = 0.08). Plasma glucose was then raised from 95 to 135 to 175 mg X dl-1 while insulin secretion was inhibited, and circulating insulin, glucagon, and growth hormone concentrations were maintained constant by infusion of these hormones and somatostatin. Glucose production and utilization rates determined with [ 14 C]-6-glucose continued to be less than those determined with [ 3 H]-2-glucose and greater than those seen with [ 3 H]-3-glucose

  3. Metabolism of tritiated D-glucose in rat erythrocytes

    International Nuclear Information System (INIS)

    Manuel y Keenoy, B.; Malaisse-Lagae, F.; Malaisse, W.J.

    1991-01-01

    The metabolism of D-[U-14C]glucose, D-[1-14C]glucose, D-[6-14C]glucose, D-[1-3H]glucose, D-[2-3H]glucose, D-[3-3H]glucose, D-[3,4-3H]glucose, D-[5-3H]glucose, and D-[6-3H]glucose was examined in rat erythrocytes. There was a fair agreement between the rate of 3HOH production from either D-[3-3H]glucose and D-[5-3H]glucose, the decrease in the 2,3-diphosphoglycerate pool, its fractional turnover rate, the production of 14C-labeled lactate from D-[U-14C]glucose, and the total lactate output. The generation of both 3HOH and tritiated acidic metabolites from D-[3,4-3H]glucose indicated incomplete detritiation of the C4 during interconversion of fructose-1,6-bisphosphate and triose phosphates. Erythrocytes unexpectedly generated 3HOH from D-[6-3H]glucose, a phenomenon possibly attributable to the detritiation of [3-3H]pyruvate in the reaction catalyzed by glutamate pyruvate transaminase. The production of 3HOH from D-[2-3H]glucose was lower than that from D-[5-3H]glucose, suggesting enzyme-to-enzyme tunneling of glycolytic intermediates in the hexokinase/phosphoglucoisomerase/phosphofructokinase sequence. The production of 3HOH from D-[1-3H]glucose largely exceeded that of 14CO2 from D-[1-14C]glucose, a situation tentatively ascribed to the generation of 3HOH in the phosphomannoisomerase reaction. It is further speculated that the adjustment in specific radioactivity of D-[1-3H]glucose-6-phosphate cannot simultaneously match the vastly different degrees of isotopic discrimination in velocity at the levels of the reactions catalyzed by either glucose-6-phosphate dehydrogenase or phosphoglucoisomerase. The interpretation of the present findings thus raises a number of questions, which are proposed as a scope for further investigations

  4. Glucose, epithelium, and enteric nervous system: dialogue in the dark.

    Science.gov (United States)

    Pfannkuche, H; Gäbel, G

    2009-06-01

    The gastrointestinal epithelium is in close contact with the various components of the chymus, including nutrients, bacteria and toxins. The epithelial barrier has to decide which components are effectively absorbed and which components are extruded. In the small intestine, a nutrient like glucose is mainly absorbed by the sodium linked glucose cotransporter 1 (SGLT1) and the glucose transporter 2 (GLUT2). The expression and activity of both transport proteins is directly linked to the amount of intraluminal glucose. Besides the direct interaction between glucose and the enterocytes, glucose also stimulates different sensory mechanisms within the intestinal wall. The most important types of cells involved in the sensing of intraluminal contents are enteroendocrine cells and neurones of the enteric nervous system. Regarding glucosensing, a distinct type of enteroendocrine cells, the enterochromaffine (EC) cells are involved. Excitation of EC cells by intraluminal glucose results in the release of serotonin (5-HT), which modulates epithelial functions and activates enteric secretomotorneurones. Enteric neurones are not only activated by 5-HT, but also directly by glucose. The activation of different cell types and the subsequent crosstalk between these cells may trigger appropriate absorptive and secretory processes within the intestine.

  5. Effect of meal composition on calcium absorption: enhancing effect of carbohydrate polymers

    International Nuclear Information System (INIS)

    Kelly, S.E.; Chawla-Singh, K.; Sellin, J.H.; Yasillo, N.J.; Rosenberg, I.H.

    1984-01-01

    Meal components including fat, fiber, and carbohydrates can influence the intestinal absorption of calcium; such interactions may be of even greater importance in the presence of intestinal disease. This study compares intestinal absorption of 47CaCl2 administered in four ways: in water, within a standard meal, with a liquid formula (Ensure, Ross Laboratories, Columbus, Ohio), or with a glucose polymer solution (Frodex-15, Ross). Studies were carried out in 9 patients with ileal resection, 3 patients with jejunoileal bypass, and 14 controls. Fractional calcium absorption from water was lower in patients than in controls. Absorption was enhanced 1.5- to 5-fold when 47CaCl2 was administered with a liquid formula diet containing a glucose polymer or with the glucose polymer alone. Patients with the lowest calcium absorption from breakfast showed the greatest effect of calcium ingestion with formula or glucose polymer. These findings further emphasize the importance of meal composition on calcium absorption and provide a possible mechanism for enhancing calcium absorption in some patients with chronically impaired absorption

  6. Hyperglycemia (High Blood Glucose)

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  7. Hyperglycemia (High Blood Glucose)

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  8. Hyperglycemia (High Blood Glucose)

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  11. 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

  12. Hyperglycemia (High Blood Glucose)

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  13. Hyperglycemia (High Blood Glucose)

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  15. 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...

  16. Hyperglycemia (High Blood Glucose)

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  17. Hyperglycemia (High Blood Glucose)

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  19. Hyperglycemia (High Blood Glucose)

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  20. Hyperglycemia (High Blood Glucose)

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  1. Hyperglycemia (High Blood Glucose)

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  3. Hyperglycemia (High Blood Glucose)

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  8. Hyperglycemia (High Blood Glucose)

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  9. Hyperglycemia (High Blood Glucose)

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  10. Hyperglycemia (High Blood Glucose)

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  12. Hyperglycemia (High Blood Glucose)

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  13. Hyperglycemia (High Blood Glucose)

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  14. Hyperglycemia (High Blood Glucose)

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  15. Hyperglycemia (High Blood Glucose)

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  16. Quasar Absorption Studies

    Science.gov (United States)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  17. Electromagnetically induced absorption via incoherent collisions

    International Nuclear Information System (INIS)

    Yang Xihua; Sheng Jiteng; Xiao Min

    2011-01-01

    We conduct theoretical studies on electromagnetically induced absorption via incoherent collisions in an inhomogeneously broadened ladder-type three-level system with the density-matrix approach. The effects of the collision-induced coherence decay rates as well as the probe laser field intensity on the probe field absorption are examined. It is shown that with the increase of the collisional decay rates in a moderate range, a narrow dip due to electromagnetically induced transparency superimposed on the Doppler-broadened absorption background can be turned into a narrow peak under the conditions that the probe field intensity is not very weak as compared to the pump field, which results from the enhancement of constructive interference and suppression of destructive interference between one-photon and multiphoton transition pathways. The physical origin of the collision-assisted electromagnetically induced absorption is analyzed with a power-series solution of the density-matrix equations.

  18. Gastrointestinal absorption of uranium in man

    International Nuclear Information System (INIS)

    Larsen, R.P.; Orlandini, K.A.

    1984-01-01

    A method has been established for determining the fractional absorption of uranium directly in man. Measurements are made of the urinary excretion rates of uranium for individuals whose drinking water has a high 234 U to 238 U activity ratio and is the primary source of 234 U in their diets. For two individuals, the values obtained for the fractional absorption of 234 U were 0.004 and 0.006. The values obtained for the fractional absorption of 238 U, using a literature value for the 238 U intake from food, were 0.008 and 0.015. The present ICRP value is 0.20. 7 references, 1 table

  19. Significance of Glucose Addition on Chitosan-Glycerophosphate Hydrogel Properties

    Directory of Open Access Journals (Sweden)

    Dian Susanthy

    2016-03-01

    Full Text Available Chitosan-glycerophosphate hydrogel can be used as dental scaffold due to its thermosensitivity, gelation performance at body temperature, suitable acidity for body condition, biocompatibility, and ability to provide good environment for cell proliferation and differentiation. Previous study showed that glucose addition to the chitosan solution before steam sterilization improved its hydrogel mechanical strength. However, the effectiveness of glucose addition was still doubted because glucose might undergo Maillard reaction in that particular condition. The aims of this study are to confirm whether the glucose addition can increase the hydrogel mechanical strength and gelation rate effectively and also to compare their performance to be dental scaffold. This research was performed through several steps, namely preparation of chitosan-glycerophosphate solution, addition of glucose, gelation time test, gel mechanical strength measurement, functional group analysis, and physical properties measurements (pH, viscosity, and pore size. The result showed that glucose addition did not improve the hydrogel mechanical strength and gelation rate, neither when it was added before nor after steam sterilization. Glucose addition before steam sterilization seemed to trigger Maillard reaction or browning effect, while glucose addition after steam sterilization increased the amount of free water molecules in the hydrogel. Chitosan and glycerophosphate interact physically, but interaction between chitosan and glucose seems to occur chemically and followed by the formation of free water molecules. Glucose addition decreases the solution viscosity and hydrogel pore size so the hydrogel performance as dental scaffold is lowered.

  20. Uranium absorption study pile

    International Nuclear Information System (INIS)

    Raievski, V.; Sautiez, B.

    1959-01-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

  1. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-06-01

    The present discussion is limited to a presentation of the most recent total photonuclear absorption experiments performed with real photons at intermediate energy, and more precisely in the region of nucleon resonances. The main sources of real photons are briefly reviewed and the experimental procedures used for total photonuclear absorption cross section measurements. The main results obtained below 140 MeV photon energy as well as above 2 GeV are recalled. The experimental study of total photonuclear absorption in the nuclear resonance region (140 MeV< E<2 GeV) is still at its beginning and some results are presented

  2. 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.

  3. Absorption heat pump system

    Science.gov (United States)

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  4. Zeeman atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given

  5. Selective conversion of plasma glucose into CO2 by Saccharomyces cerevisiae for the measurement of C-13 abundance by isotope ratio mass spectrometry : proof of principle

    NARCIS (Netherlands)

    Rembacz, Krzysztof P.; Faber, Klaas Nico; Stellaard, Frans

    2007-01-01

    To study carbohydrate digestion and glucose absorption, time-dependent C-13 enrichment in plasma glucose is measured after oral administration of naturally occurring C-13-enriched carbohydrates. The isotope enrichment of the administered carbohydrate is low (APE <0.1%) and plasma C-13 glucose

  6. Alterations in glucose kinetics induced by pentobarbital anesthesia

    International Nuclear Information System (INIS)

    Lang, C.H.; Bagby, G.J.; Spitzer, J.J.

    1986-01-01

    Pentobarbital is a common anesthetic agent used in animal research that is known to alter sympathetic function and may also affect carbohydrate metabolism. The in vivo effects of iv pentobarbital on glucose homeostasis were studied in chronically catheterized fasted rats. Whole body glucose kinetics, assessed by the constant iv infusion of [6- 3 H]- and [U- 14 C]-glucose, were determined in all rats in the conscious state. Thereafter, glucose metabolism was followed over the next 4 hr in 3 subgroups of rats; conscious, anesthetized with body temperature maintained, and anesthetized with body temperature not maintained. Hypothermia (a 5 0 C decrease) developed spontaneously in anesthetized rats kept at ambient temperature (22 0 C). No differences were seen in MABP and heart rate between conscious and normothermic anesthetized rats; however, hypothermic anesthetized rats showed a decrease in MABP (20%) and heart rate (35%). Likewise, plasma glucose and lactate concentrations, the rate of glucose appearance (Ra), recycling and metabolic clearance (MCR) did not differ between conscious and normothermic anesthetized animals. In contrast, hypothermic anesthetized rats showed a 50% reduction in plasma lactate, a 40% drop in glucose Ra, and a 30-40% decrease in glucose recycling and MCR. Thus, pentobarbital does not appear to alter in vivo glucose kinetics, compared to unanesthetized controls, provided that body temperature is maintained

  7. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...... learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning...

  8. Comment on resonant absorption

    International Nuclear Information System (INIS)

    Hammerling, P.

    1977-01-01

    An average over angles of incidence of the usual resonant absorption function is presented. This form is appropriate under experimental conditions where the angles of incidence vary greatly and in an unknown manner. For comparison a lens-ellipsoidal mirror illumination system with a known longitudinal aberration is considered. In the latter example the angles of incidence are readily obtained and the resulting resonance absorption function evaluated. The associated fields are calculated in a similar fashion. (author)

  9. Optical absorption measurement system

    International Nuclear Information System (INIS)

    Draggoo, V.G.; Morton, R.G.; Sawicki, R.H.; Bissinger, H.D.

    1989-01-01

    This patent describes a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature

  10. 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

  11. Oxytocin increases extrapancreatic glucagon secretion and glucose production in pancreatectomized dogs

    International Nuclear Information System (INIS)

    Altszuler, N.; Puma, F.; Winkler, B.; Fontan, N.; Saudek, C.D.

    1986-01-01

    Infusion of oxytocin into normal dogs increases plasma levels of insulin and glucagon and glucose production and uptake. To determine whether infused oxytocin also increases glucagon secretion from extrapancreatic sites, pancreatectomized dogs, off insulin of 18 hr, were infused with oxytocin and plasma glucagon, and glucose production and uptake were measured using the [6- 3 H]glucose primer-infusion technique. The diabetic dogs, in the control period, had elevated plasma glucose and glucagon levels, an increased rate of glucose production, and a relative decrease in glucose uptake (decreased clearance). Infusion of oxytocin (500 μU/kg/min) caused a rise in plasma glucagon and glucose levels, increased glucose production, and further decreased glucose clearance. it is concluded that oxytocin can stimulate secretion of extrapancreatic glucagon, which contributes to the increased glucose production

  12. Dose-response relationship between probability of pathologic tumor control and glucose metabolic rate measured with FDG PET after preoperative chemoradiotherapy in locally advanced non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Choi, Noah C.; Fischman, Alan J.; Niemierko, Andrzej; Ryu, Jin-Sook; Lynch, Thomas; Wain, John; Wright, Cameron; Fidias, Panos; Mathisen, Douglas

    2002-01-01

    Purpose: To determine the dose-response relationship between the probability of tumor control on the basis of pathologic tumor response (pTCP) and the residual metabolic rate of glucose (MRglc) in response to preoperative chemoradiotherapy in locally advanced non-small-cell lung cancer and to define the level of residual MRglc that corresponds to pTCP 50% and pTCP ≥95%. Methods and Materials: Quantitative dynamic 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography was performed to measure regional MRglc at the primary lesion before and 2 weeks after preoperative chemoradiotherapy in an initial group of 13 patients with locally advanced NSCLC. A simplified kinetic method was developed subsequently from the initial dynamic study and used in the subsequent 16 patients. The preoperative radiotherapy programs consisted of (1) a split course of 42 Gy in 28 fractions within a period of 28 days using a twice-daily treatment schedule for Stage IIIA(N2) NSCLC (n=18) and (2) standard once-daily radiation schedule of 45-63 Gy in 25-35 fractions during a 5-7-week period (n=11). The preoperative chemotherapy regimens included two cycles of cisplatin, vinblastine, and 5-fluorouracil (n=24), cisplatin and etoposide (n=2), and cisplatin, Taxol, and 5-fluorouracil (n=3). Patients free of tumor progression after preoperative chemoradiotherapy underwent surgery. The degree of residual MRglc measured 2 weeks after preoperative chemoradiotherapy and 2 weeks before surgery was correlated with the pathologic tumor response. The relationship between MRglc and pTCP was modeled using logistic regression. Results: Of 32 patients entered into the study, 29 (16 men and 13 women; 30 lesions) were evaluated for the correlation between residual MRglc and pathologic tumor response. Three patients did not participate in the second study because of a steady decline in general condition. The median age was 60 years (range 42-78). One of the 29 patients had two separate lesions, and

  13. Pro-aging effects of glucose signaling through a G protein-coupled glucose receptor in fission yeast.

    Directory of Open Access Journals (Sweden)

    Antoine E Roux

    2009-03-01

    Full Text Available Glucose is the preferred carbon and energy source in prokaryotes, unicellular eukaryotes, and metazoans. However, excess of glucose has been associated with several diseases, including diabetes and the less understood process of aging. On the contrary, limiting glucose (i.e., calorie restriction slows aging and age-related diseases in most species. Understanding the mechanism by which glucose limits life span is therefore important for any attempt to control aging and age-related diseases. Here, we use the yeast Schizosaccharomyces pombe as a model to study the regulation of chronological life span by glucose. Growth of S. pombe at a reduced concentration of glucose increased life span and oxidative stress resistance as reported before for many other organisms. Surprisingly, loss of the Git3 glucose receptor, a G protein-coupled receptor, also increased life span in conditions where glucose consumption was not affected. These results suggest a role for glucose-signaling pathways in life span regulation. In agreement, constitutive activation of the Galpha subunit acting downstream of Git3 accelerated aging in S. pombe and inhibited the effects of calorie restriction. A similar pro-aging effect of glucose was documented in mutants of hexokinase, which cannot metabolize glucose and, therefore, are exposed to constitutive glucose signaling. The pro-aging effect of glucose signaling on life span correlated with an increase in reactive oxygen species and a decrease in oxidative stress resistance and respiration rate. Likewise, the anti-aging effect of both calorie restriction and the Deltagit3 mutation was accompanied by increased respiration and lower reactive oxygen species production. Altogether, our data suggest an important role for glucose signaling through the Git3/PKA pathway to regulate S. pombe life span.

  14. Effect of anesthesia on glucose production and utilization in rats

    International Nuclear Information System (INIS)

    Penicaud, L.; Ferre, P.; Kande, J.; Leturque, A.; Issad, T.; Girard, J.

    1987-01-01

    This study was undertaken to determine the effects of pentobarbital anesthesia (50 mg/kg ip) on glucose kinetics and individual tissue glucose utilization in vivo, in chronically catheterized rats. Glucose turnover studies were carried out using [3- 3 H] glucose as tracer. A transient hyperglycemia and an increased glucose production were observed 3 min after induction of anesthesia. However, 40 min after induction of anesthesia, glycemia returned to the level observed in awake animals, whereas glucose turnover was decreased by 30% as compared with unanesthetized rats. These results are discussed with regard to the variations observed in plasma insulin, glucagon, and catecholamine levels. Glucose utilization by individual tissues was studied by the 2-[1- 3 H] deoxyglucose technique. A four- to fivefold decrease in glucose utilization was observed in postural muscles (soleus and adductor longus), while in other nonpostural muscles (epitrochlearis, tibialis anterior, extensor digitorum longus, and diaphragm) and other tissues (white and brown adipose tissues) anesthesia did not modify the rate of glucose utilization. A decrease in glucose utilization was also observed in the brain

  15. Heavy nucleus resonance absorption in heterogeneous lattices

    International Nuclear Information System (INIS)

    Coste, M.; Tellier, H.; Brienne-Raepsaet, C.; Van Der Gucht, C.

    1992-01-01

    To compute easily the neutron reaction rates in the resonance energy range, the reactor physicists use the self-shielding formalism and the effective cross-section concept. Usually, for these calculations, and equivalence process is used, in such a way that the absorption rate is correctly computed for the whole fuel pin. This procedure does not allow to preserve the spatial absorption rate distribution inside the pin. It is an important handicap if we want to reproduce the plutonium distribution in a spent fuel. To avoid this inconvenience, new improvements of the self-shielding formalism have been recently introduced in the new assembly calculation code of the French Atomic Energy Commission, APOLLO 2. With this improved formalism, it is now possible to represent the spatial and energetic dependence of the heavy nucleus absorption inside the fuel pin and to use a fine energy dependent equivalence process. As it does not exist clean experimental results for the spatial and energetic dependence of the absorption, the authors used reference calculations to qualify the self-shielding formalism. For the strongly self-shielded nuclei of interest in reactor physics, U238, Pu240 and Th232, the agreement between the self-shielding calculation and the reference ones is fairly good for the spatial and energetic dependence of the absorption rate

  16. Lithium absorption by the rabbit gall-bladder

    DEFF Research Database (Denmark)

    Hansen, C P; Holstein-Rathlou, N H; Skøtt, O

    1991-01-01

    Lithium (Li+) absorption across the low-resistance epithelium of the rabbit gall-bladder was studied in order to elucidate possible routes and mechanisms of Li+ transfer. Li+ at a concentration of 0.4 mM in both mucosal and serosal media did not affect isosmotic mucosa-to-serosa fluid absorption...... was elicited from the mucosal side and was not accounted for by compensatory Li+ absorption; water and Na+ absorption rates decreased nearly in parallel. The effects of 0.4 mM amiloride and of substitution with 20 mM Li+ were only partly additive. It is concluded that Li+ absorption in the rabbit gall...

  17. The effects of hypoglycin on glucose metabolism in the rat

    International Nuclear Information System (INIS)

    Osmundsen, H.; Billington, D.; Taylor, J.R.; Sherratt, H.S.A.

    1978-01-01

    The kinetics of glucose metabolism were evaluated in rats deprived of food 15 to 21 h after the administration of hypoglycaemic doses of hypoglycin (100 mg/kg body wt.) by following changes in the specific radioactivities of 14 C and 3 H in blood glucose after an intravenous dose of [U- 14 C,2- 3 H]glucose. During this time, recycling of glucose through the Cori cycle was virtually abolished, the rate of irreversible disposal of glucose and its total body mass were both decreased by about 70%, whereas there was little effect on the mean transit time for glucose. It was concluded that hypoglycaemia is due to inhibition of gluconeogenesis. (author)

  18. Vitamin A absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Investigation of the absorption of vitamin A and related substances is complicated by the multiplicity of forms in which they occur in the diet and by the possibility that they may be subject to different mechanisms of absorption. Present knowledge of these mechanisms is inadequate, especially in the case of carotenoids. Numerous tests of absorption have been developed. The most common has been the biochemical measurement of the rise in plasma vitamin A after an oral dose of retinol or retinyl ester, but standardization is inadequate. Radioisotope tests based upon assay of serum or faecal activity following oral administration of tritiated vitamin A derivaties hold considerable promise, but again standardization is inadequate. From investigations hitherto performed it is known that absorption of vitamin A is influenced by several diseases, although as yet the consistency of results and the correlation with other tests of intestinal function have often been poor. However, the test of vitamin A absorption is nevertheless of clinical importance as a specialized measure of intestinal function. (author)

  19. Insulin analogues with improved absorption characteristics.

    Science.gov (United States)

    Brange, J; Hansen, J F; Langkjaer, L; Markussen, J; Ribel, U; Sørensen, A R

    1992-01-01

    The insulin preparations available today are not ideal for therapy as s.c. injection does not provide a physiological insulin profile. With the aim to improve the absorption properties recombinant DNA technology has been utilized to design novel insulin molecules with changed physico-chemical characteristics and hence altered subcutaneous absorption kinetics. Soluble, long-acting human insulin analogues in which the isoelectric point has been increased from 5.4 to approx. 7 are absorbed very slowly, providing a more constant basal insulin delivery with lower day-to-day variation than present protracted preparations. In addition they have better storage stability. Rapid-acting human insulin analogues with largely reduced self-association are absorbed substantially faster from subcutaneous tissue than current regular insulin and thus are better suited for bolus injection. The absorption kinetics of these analogues have been able to explain the mechanism behind the dose effect on insulin absorption rate.

  20. Quantitative kinetics of renal glucose metabolism by the isotope dilution method in the unanesthetized sheep

    International Nuclear Information System (INIS)

    Sasaki, Shin-ichi; Watanabe, Yasukuni; Ambo, Kaichi; Tsuda, Tsuneyuki.

    1982-01-01

    Renal glucose production and utilization rates in normal fed and fasted sheep were determined by the measurements of renal blood flow and arteriovenous 14 C-glucose and glucose concentration differences using the method of primed continuous infusion of u- 14 C-glucose. At the same time total body glucose turnover rate was measured, and the contribution of renal glucose production to glucose requirement in the whole animal was quantitatively estimated. The renal blood flow for fed and fasted sheep were 20 +- 1 and 20 +- 3 ml/min/kg, respectively. No significant difference in the renal blood flow existed between the groups. The total body glucose turnover rate in fasted sheep (1.68 +- 0.20 mg/min/kg) was significantly lowered (P < 0.01) than that of fed sheep (2.20 +- 0.13 mg/min/kg). The renal glucose production rate in fed sheep was 0.47 +- 0.05 mg/min/kg and this rate accounted for about 21.4% of the glucose turnover rate. The renal glucose production rate in fasted sheep decreased to about 45% of that in fed sheep. However, the renal glucose utilization rate was similar in fed (0.26 +- 0.04 mg/min/kg) and fasted sheep (0.27 +- 0.04 mg/min/kg). Net renal glucose production rate in fed sheep, which was measured by the method of arteriovenous glucose concentration differences, was 0.22 +- 0.05 mg/min/kg, but that in fasted sheep was a negative value. These results suggest that the kidney of ruminant seems to produce a significant amount of glucose and to utilize it simultaneously with production. (author)

  1. Assessment of insulin action in insulin-dependent diabetes mellitus using [6(14)C]glucose, [3(3)H]glucose, and [2(3)H]glucose. Differences in the apparent pattern of insulin resistance depending on the isotope used

    International Nuclear Information System (INIS)

    Bell, P.M.; Firth, R.G.; Rizza, R.A.

    1986-01-01

    To determine whether [2(3)H], [3(3)H], and [6(14)C]glucose provide an equivalent assessment of glucose turnover in insulin-dependent diabetes mellitus (IDDM) and nondiabetic man, glucose utilization rates were measured using a simultaneous infusion of these isotopes before and during hyperinsulinemic euglycemic clamps. In the nondiabetic subjects, glucose turnover rates determined with [6(14)C]glucose during insulin infusion were lower (P less than 0.02) than those determined with [2(3)H]glucose and higher (P less than 0.01) than those determined with [3(3)H]glucose. In IDDM, glucose turnover rates measured with [6(14)C]glucose during insulin infusion were lower (P less than 0.05) than those determined with [2(3)H]glucose, but were not different from those determined with [3(3)H]glucose. All three isotopes indicated the presence of insulin resistance. However, using [3(3)H]glucose led to the erroneous conclusion that glucose utilization was not significantly decreased at high insulin concentrations in the diabetic patients. [6(14)C] and [3(3)H]glucose but not [2(3)H]glucose indicated impairment in insulin-induced suppression of glucose production. These results indicate that tritiated isotopes do not necessarily equally reflect the pattern of glucose metabolism in diabetic and nondiabetic man

  2. Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

    DEFF Research Database (Denmark)

    Ploug, T; Stallknecht, B M; Pedersen, O

    1990-01-01

    exhaustive single exercise session the day before experiment both maximum insulin- and contraction-stimulated transport rates were increased in all muscle types in trained rats. Accordingly, the increased glucose transport capacity in trained muscle was not due to a residual effect of the last training...... session. Half-times for reversal of contraction-induced glucose transport were similar in trained and untrained muscles. The concentrations of mRNA for GLUT-1 (the erythrocyte-brain-Hep G2 glucose transporter) and GLUT-4 (the adipocyte-muscle glucose transporter) were increased approximately twofold......The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers...

  3. Triglyceride synthesis in epididymal adipose tissue: contribution of glucose and non-glucose carbon sources.

    Science.gov (United States)

    Bederman, Ilya R; Foy, Steven; Chandramouli, Visvanathan; Alexander, James C; Previs, Stephen F

    2009-03-06

    The obesity epidemic has generated interest in determining the contribution of various pathways to triglyceride synthesis, including an elucidation of the origin of triglyceride fatty acids and triglyceride glycerol. We hypothesized that a dietary intervention would demonstrate the importance of using glucose versus non-glucose carbon sources to synthesize triglycerides in white adipose tissue. C57BL/6J mice were fed either a low fat, high carbohydrate (HC) diet or a high fat, carbohydrate-free (CF) diet and maintained on 2H2O (to determine total triglyceride dynamics) or infused with [6,6-(2)H]glucose (to quantify the contribution of glucose to triglyceride glycerol). The 2H2O labeling data demonstrate that although de novo lipogenesis contributed approximately 80% versus approximately 5% to the pool of triglyceride palmitate in HC- versus CF-fed mice, the epididymal adipose tissue synthesized approximately 1.5-fold more triglyceride in CF- versus HC-fed mice, i.e. 37+/-5 versus 25+/-3 micromolxday(-1). The [6,6-(2)H]glucose labeling data demonstrate that approximately 69 and approximately 28% of triglyceride glycerol is synthesized from glucose in HC- versus CF-fed mice, respectively. Although these data are consistent with the notion that non-glucose carbon sources (e.g. glyceroneogenesis) can make substantial contributions to the synthesis of triglyceride glycerol (i.e. the absolute synthesis of triglyceride glycerol from non-glucose substrates increased from approximately 8 to approximately 26 micromolxday(-1) in HC- versus CF-fed mice), these observations suggest (i) the importance of nutritional status in affecting flux rates and (ii) the operation of a glycerol-glucose cycle.

  4. Facilitated transport of glucose from blood to brain in man and the effect of moderate hypoglycaemia on cerebral glucose utilization

    International Nuclear Information System (INIS)

    Blomqvist, G.; Widen, L.; Hellstrand, E.; Gutniak, M.; Grill, V.

    1991-01-01

    The effect of steady-state moderate hypoglycaemia on human brain homeostasis has been studied with positron emission tomography using D-glucose 11 C(ul) as tracer. To rule out any effects of insulin, the plasma insulin concentration was maintained at the same level under normo- and hypoglycaemic conditions. Reduction of blood glucose by 55% increased the glucose clearance through the blood-brain barrier by 50% and reduced brain glucose consumption by 40%. Blood flow was not affected. The results are consistent with facilitated transport of glucose from blood to brain in humans. The maximal transport rate of glucose from blood to brain was found to be 62±19 (mean±SEM) μmol hg -1 min -1 , and the half-saturation constant was found to be 4.1±3.2 mM. (orig.)

  5. Does overnight normalization of plasma glucose by insulin infusion affect assessment of glucose metabolism in Type 2 diabetes?

    DEFF Research Database (Denmark)

    Staehr, P; Højlund, Kurt; Hother-Nielsen, O

    2003-01-01

    AIMS: In order to perform euglycaemic clamp studies in Type 2 diabetic patients, plasma glucose must be reduced to normal levels. This can be done either (i) acutely during the clamp study using high-dose insulin infusion, or (ii) slowly overnight preceding the clamp study using a low-dose insulin...... infusion. We assessed whether the choice of either of these methods to obtain euglycaemia biases subsequent assessment of glucose metabolism and insulin action. METHODS: We studied seven obese Type 2 diabetic patients twice: once with (+ ON) and once without (- ON) prior overnight insulin infusion. Glucose...... turnover rates were quantified by adjusted primed-constant 3-3H-glucose infusions, and insulin action was assessed in 4-h euglycaemic, hyperinsulinaemic (40 mU m-2 min-1) clamp studies using labelled glucose infusates (Hot-GINF). RESULTS: Basal plasma glucose levels (mean +/- sd) were 5.5 +/- 0.5 and 10...

  6. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... around 4:00 a.m. to 5:00 a.m.). What are the Symptoms of Hyperglycemia? The signs and symptoms include the following: High blood glucose High levels of sugar in the urine Frequent urination Increased ...

  7. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online Community ... Page Text Size: A A A Listen En Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical ...

  8. Low Blood Glucose (Hypoglycemia)

    Science.gov (United States)

    ... 24 hours after the activity. Drinking too much alcohol without enough food Alcohol makes it harder for your body to keep ... t eaten in a while. The effects of alcohol can also keep you from feeling the ... able to eat as much or keep food down, which can cause low blood glucose. Learn ...

  9. Hyperglycemia (High Blood Glucose)

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    Full Text Available ... A A A Listen En Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical term for high ... function (data) { $('#survey-errors').remove(); $('.survey-form .form-group .survey-alert-wrap').remove(); if (data.submitSurveyResponse.success == ' ...

  10. Blood Glucose Monitoring Devices

    Science.gov (United States)

    ... are below 100 mg/dL before meals and fasting and are less than 140 mg/dL two hours after meals. People with diabetes should consult their doctor or health care provider to set appropriate blood glucose goals. ...

  11. Hyperglycemia (High Blood Glucose)

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  12. Hyperglycemia (High Blood Glucose)

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  13. Hyperglycemia (High Blood Glucose)

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    Full Text Available ... Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy ... de Cure Women's Series Do-It-Yourself Fundraising Become a Volunteer American Diabetes Month® American Diabetes Association ...

  14. Hyperglycemia (High Blood Glucose)

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    Full Text Available ... Text Size: A A A Listen En Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical term ... body can't use insulin properly. What Causes Hyperglycemia? A number of things can cause hyperglycemia: If ...

  15. Hyperglycemia (High Blood Glucose)

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    Full Text Available ... Research & Practice Ways to Give Close Are You at Risk? Home Prevention Diagnosing Diabetes and Learning About Prediabetes Type 2 Diabetes Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose ...

  16. Hyperglycemia (High Blood Glucose)

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    Full Text Available ... You At Risk? Diabetes Basics Living with Diabetes Food & Fitness In My Community Advocacy Research & Practice Ways to Give Close Are You at Risk? Home ... work with your doctor to find the safest way for you to lower your blood glucose ... down on the amount of food you eat might also help. Work with your ...

  17. Hyperglycemia (High Blood Glucose)

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    Full Text Available ... You at Risk? Home Prevention Diagnosing Diabetes and Learning About Prediabetes Type 2 Diabetes Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day Diabetes Basics ...

  18. Hyperglycemia (High Blood Glucose)

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    Full Text Available ... Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools ... Complications DKA (Ketoacidosis) & Ketones Kidney Disease ... than planned or exercised less than planned. You have stress from an illness, such as a cold or flu. You have ...

  19. Absorption of pentacaine from ulcerous rat stomach

    International Nuclear Information System (INIS)

    Tomcikova, O.; Babulova, A.; Durisova, M.; Trnovec, T.; Benes, L.

    1985-01-01

    Pentacaine is a local anaesthetic which exhibited positive effects on healing of model ulcers in the rat stomach. The in situ disappearance of pentacaine from the ulcerous and intact rat stomach was studied. Gastric ulcers were produced by oral administration of phenylbutazone (200 mg/kg) 3.5 h before absorption experiment. Pentacaine exhibited a biexponential decrease from the lumen of the stomach, the rate of which was essentially the same in both groups. The total amount of pentacaine absorbed was small because of extremly low absorption rate. (author)

  20. Bayesian model discrimination for glucose-insulin homeostasis

    DEFF Research Database (Denmark)

    Andersen, Kim Emil; Brooks, Stephen P.; Højbjerre, Malene

    In this paper we analyse a set of experimental data on a number of healthy and diabetic patients and discuss a variety of models for describing the physiological processes involved in glucose absorption and insulin secretion within the human body. We adopt a Bayesian approach which facilitates...... as parameter uncertainty. Markov chain Monte Carlo methods are used, combining Metropolis Hastings, reversible jump and simulated tempering updates to provide rapidly mixing chains so as to provide robust inference. We demonstrate the methodology for both healthy and type II diabetic populations concluding...... that whilst both populations are well modelled by a common insulin model, their glucose dynamics differ considerably....

  1. Regional differences in adipocyte lactate production from glucose

    International Nuclear Information System (INIS)

    Newby, F.D.; Sykes, M.N.; DiGirolamo, M.

    1988-01-01

    Having shown that lactate is an important product of glucose metabolism by rat epididymal adipocytes, the authors investigated possible regional differences in adipocyte lactate production and the role of the animals' nutritional state and stage of development. [U- 14 C]glucose metabolism, lactate production, and response to insulin were measured in fat cells isolated from four adipose regions from young lean and older fatter rats, killed either in the fed state or after fasting for 48 h. In the absence of insulin, mesenteric fat cells from either age group metabolized significantly more glucose per cell and converted more glucose to lactate than cells from other depots, regardless of nutritional state. Adipocytes from fasted lean rats showed a significant increase in the relative glucose conversion to lactate in all depots when compared with cells from fed lean rats. Fasting of older fatter rats, however, had limited effects on the relative adipocyte glucose conversion to lactate since lactate production was already high. Mesenteric fat cells had the lowest relative response to insulin, possibly due to the high basal rate of glucose metabolism. These findings indicate that differences exist among adipose regions in the rates of glucose metabolism, lactate production and response to insulin. The anatomical location of the mesenteric adipose depot, coupled with a high metabolic rate and blood perfusion, suggests that mesenteric adipocytes may provide a unique and more direct contribution of metabolic substrates for hepatic metabolism than adipocytes from other depots

  2. Whole body glucose kinetics in type I diabetes studied with [6,6-2H] and [U-13C]-glucose and the artificial B-cell

    International Nuclear Information System (INIS)

    Darmaun, D.; Cirillo, D.; Koziet, J.; Chauvet, D.; Young, V.R.; Robert, J.J.

    1988-01-01

    Dynamic aspects of whole body glucose metabolism were assessed in ten young adult insulin-dependent (type I) diabetic men. Using a primed, continuous intravenous infusion of [6,6- 2 H]glucose and [U- 13 C]glucose, endogenous production, tissue uptake, carbon recycling, and oxidation of glucose were measured in the postabsorptive state. These studies were undertaken after blood glucose had been maintained overnight at 5.9 +/- 0.4 mmol/L (n = 10), and on another night at 10.5 +/- 0.4 mmol/L (n = 4) or 15.2 +/- 0.6 mmol/L (n = 6). In the normoglycemic state, endogenous glucose production averaged 2.15 +/- 0.13 mg x kg-1 x min-1. This value, as well as the rate of glucose carbon recycling (0.16 +/- 0.04 mg x kg-1 x min-1) and glucose oxidation (1.52 +/- 0.16 mg x kg-1 x min-1) are comparable to those found in nondiabetic controls. In the hyperglycemic states at 10 or 15 mmol/L, endogenous glucose production was increased by 11% (P less than .01) and 60% (P less than .01) compared to the normoglycemic states, respectively. Glucose carbon recycling contributed only a small percentage to this variation in glucose production (15% at the 15 mmol/L glucose level). This suggests that if gluconeogenesis participates in the increased glucose output, it is not dependent on a greater systemic supply of three-carbon precursors. The increased rate of glucose production in the hyperglycemic state was quantitatively offset by a rise in urinary glucose excretion. Glucose tissue uptake, as well as glucose oxidation, did not vary between normoglycemic and hyperglycemic states

  3. Transport equations in an enzymatic glucose fuel cell

    Science.gov (United States)

    Jariwala, Soham; Krishnamurthy, Balaji

    2018-01-01

    A mathematical model is developed to study the effects of convective flux and operating temperature on the performance of an enzymatic glucose fuel cell with a membrane. The model assumes isothermal operating conditions and constant feed rate of glucose. The glucose fuel cell domain is divided into five sections, with governing equations describing transport characteristics in each region, namely - anode diffusion layer, anode catalyst layer (enzyme layer), membrane, cathode catalyst layer and cathode diffusion layer. The mass transport is assumed to be one-dimensional and the governing equations are solved numerically. The effects flow rate of glucose feed on the performance of the fuel cell are studied as it contributes significantly to the convective flux. The effects of operating temperature on the performance of a glucose fuel cell are also modeled. The cell performances are compared using cell polarization curves, which were found compliant with experimental observations.

  4. Alligators and Crocodiles Have High Paracellular Absorption of Nutrients, But Differ in Digestive Morphology and Physiology.

    Science.gov (United States)

    Tracy, Christopher R; McWhorter, Todd J; Gienger, C M; Starck, J Matthias; Medley, Peter; Manolis, S Charlie; Webb, Grahame J W; Christian, Keith A

    2015-12-01

    Much of what is known about crocodilian nutrition and growth has come from animals propagated in captivity, but captive animals from the families Crocodilidae and Alligatoridae respond differently to similar diets. Since there are few comparative studies of crocodilian digestive physiology to help explain these differences, we investigated young Alligator mississippiensis and Crocodylus porosus in terms of (1) gross and microscopic morphology of the intestine, (2) activity of the membrane-bound digestive enzymes aminopeptidase-N, maltase, and sucrase, and (3) nutrient absorption by carrier-mediated and paracellular pathways. We also measured gut morphology of animals over a larger range of body sizes. The two species showed different allometry of length and mass of the gut, with A. mississippiensis having a steeper increase in intestinal mass with body size, and C. porosus having a steeper increase in intestinal length with body size. Both species showed similar patterns of magnification of the intestinal surface area, with decreasing magnification from the proximal to distal ends of the intestine. Although A. mississippiensis had significantly greater surface-area magnification overall, a compensating significant difference in gut length between species meant that total surface area of the intestine was not significantly different from that of C. porosus. The species differed in enzyme activities, with A. mississippiensis having significantly greater ability to digest carbohydrates relative to protein than did C. porosus. These differences in enzyme activity may help explain the differences in performance between the crocodilian families when on artificial diets. Both A. mississippiensis and C. porosus showed high absorption of 3-O methyl d-glucose (absorbed via both carrier-mediated and paracellular transport), as expected. Both species also showed surprisingly high levels of l-glucose-uptake (absorbed paracellularly), with fractional absorptions as high as those

  5. Evaluating the clinical accuracy of two continuous glucose sensors using continuous glucose-error grid analysis.

    Science.gov (United States)

    Clarke, William L; Anderson, Stacey; Farhy, Leon; Breton, Marc; Gonder-Frederick, Linda; Cox, Daniel; Kovatchev, Boris

    2005-10-01

    To compare the clinical accuracy of two different continuous glucose sensors (CGS) during euglycemia and hypoglycemia using continuous glucose-error grid analysis (CG-EGA). FreeStyle Navigator (Abbott Laboratories, Alameda, CA) and MiniMed CGMS (Medtronic, Northridge, CA) CGSs were applied to the abdomens of 16 type 1 diabetic subjects (age 42 +/- 3 years) 12 h before the initiation of the study. Each system was calibrated according to the manufacturer's recommendations. Each subject underwent a hyperinsulinemic-euglycemic clamp (blood glucose goal 110 mg/dl) for 70-210 min followed by a 1-mg.dl(-1).min(-1) controlled reduction in blood glucose toward a nadir of 40 mg/dl. Arterialized blood glucose was determined every 5 min using a Beckman Glucose Analyzer (Fullerton, CA). CGS glucose recordings were matched to the reference blood glucose with 30-s precision, and rates of glucose change were calculated for 5-min intervals. CG-EGA was used to quantify the clinical accuracy of both systems by estimating combined point and rate accuracy of each system in the euglycemic (70-180 mg/dl) and hypoglycemic (<70 mg/dl) ranges. A total of 1,104 data pairs were recorded in the euglycemic range and 250 data pairs in the hypoglycemic range. Overall correlation between CGS and reference glucose was similar for both systems (Navigator, r = 0.84; CGMS, r = 0.79, NS). During euglycemia, both CGS systems had similar clinical accuracy (Navigator zones A + B, 88.8%; CGMS zones A + B, 89.3%, NS). However, during hypoglycemia, the Navigator was significantly more clinically accurate than the CGMS (zones A + B = 82.4 vs. 61.6%, Navigator and CGMS, respectively, P < 0.0005). CG-EGA is a helpful tool for evaluating and comparing the clinical accuracy of CGS systems in different blood glucose ranges. CG-EGA provides accuracy details beyond other methods of evaluation, including correlational analysis and the original EGA.

  6. Noble gas absorption process

    International Nuclear Information System (INIS)

    Thomas, J.W.

    1975-01-01

    A method of removing a noble gas from air comprising the use of activated carbon filters in stages in which absorption and desorption steps in succession are conducted in order to increase the capacity of the filters is described. (U.S.)

  7. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-01-01

    Experimental methods using real photon beams for measurements of total photonuclear absorption cross section σ(Tot : E/sub γ/) are recalled. Most recent σ(Tot : E/sub γ/)results for complex nuclei and in the nucleon resonance region are presented

  8. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  9. Glucose effectiveness in nondiabetic relatives

    DEFF Research Database (Denmark)

    Egede, M B; Henriksen, J-E; Durck, T T

    2014-01-01

    AIMS: Reduced glucose effectiveness is a predictor of future glucose tolerance in individuals with a family history of type 2 diabetes. We examined retrospectively at 10 years in normoglycemic relatives of diabetic subjects (RELs) the pathophysiological role of glucose effectiveness in the develo...

  10. Absorption of carbon dioxide in waste tanks

    International Nuclear Information System (INIS)

    Hobbs, D.T.

    1987-01-01

    Air flow rates and carbon dioxide concentrations of air entering and exiting eight H-Area waste tanks were monitored for a period of one year. The average instanteous concentration of carbon dioxide in air is within the range reported offsite, and therefore is not affect by operation of the coal-fired power plant adjacent to the tank farm. Waste solutions in each of the tanks were observed to be continuously absorbing carbon dioxide. The rate of absorption of carbon dioxide decreased linearly with the pH of the solution. Personnel exposure associated with the routine sampling and analysis of radioactive wastes stored at SRP to determine the levels of corrosion inhibitors in solution could be reduced by monitoring the absorption of carbon dioxide and using the relationship between pH and carbon dioxide absorption to determine the free hydroxide concentration in solution

  11. Glucose metabolism and recycling by hepatocytes of OB/OB and ob/ob mice

    International Nuclear Information System (INIS)

    Lahtela, J.T.; Wals, P.A.; Katz, J.

    1990-01-01

    Hepatocytes were prepared from livers of ob/ob (obese diabetic) mice and their lean (OB/OB) siblings that had been fasted for 24 h. The hepatocytes were incubated with [U-14C, 2-3H]-, [U-14C, 3-3H]-, and [U-14C, 6-3H]glucose at concentrations from 20 to 120 mM. 14C was recovered mainly in CO2, glycogen, and lactate. Tritium was recovered in water and glycogen. The yield in labeled products from [2-3H]glucose ranged from two to three times that from [U-14C]glucose. The yields from [3-3H]- and [6-3H]glucose were similar, and 1.3-1.7 times that from [U-14C]glucose. At 40 mM, total utilization of glucose by obese mice was about twice that for lean mice, but there was little difference at 120 mM. The rate of recycling between glucose and glucose 6-phosphate was calculated. An equation to calculate the rate of recycling of glucose from the 2-3H/U-14C ratio in glycogen is derived in the APPENDIX. Our results show that (1) the utilization of glucose by hepatocytes from obese diabetic mice exceeds that of their lean controls, (2) the rate of glucose phosphorylation in both groups greatly exceeds glucose uptake and the rate of glycogen synthesis, (3) glucose phosphorylation represents a difference between a high glucokinase rate and hydrolysis of glucose 6-phosphate, and (4) recycling of glucose carbon between glucose 6-phosphate and pyruvate occurs within mouse hepatocytes

  12. Dietary fructose and glucose differentially affect lipid and glucose homeostasis.

    Science.gov (United States)

    Schaefer, Ernst J; Gleason, Joi A; Dansinger, Michael L

    2009-06-01

    Absorbed glucose and fructose differ in that glucose largely escapes first-pass removal by the liver, whereas fructose does not, resulting in different metabolic effects of these 2 monosaccharides. In short-term controlled feeding studies, dietary fructose significantly increases postprandial triglyceride (TG) levels and has little effect on serum glucose concentrations, whereas dietary glucose has the opposite effects. When dietary glucose and fructose have been directly compared at approximately 20-25% of energy over a 4- to 6-wk period, dietary fructose caused significant increases in fasting TG and LDL cholesterol concentrations, whereas dietary glucose did not, but dietary glucose did increase serum glucose and insulin concentrations in the postprandial state whereas dietary fructose did not. When fructose at 30-60 g ( approximately 4-12% of energy) was added to the diet in the free-living state, there were no significant effects on lipid or glucose biomarkers. Sucrose and high-fructose corn syrup (HFCS) contain approximately equal amounts of fructose and glucose and no metabolic differences between them have been noted. Controlled feeding studies at more physiologic dietary intakes of fructose and glucose need to be conducted. In our view, to decrease the current high prevalence of obesity, dyslipidemia, insulin resistance, and diabetes, the focus should be on restricting the intake of excess energy, sucrose, HFCS, and animal and trans fats and increasing exercise and the intake of vegetables, vegetable oils, fish, fruit, whole grains, and fiber.

  13. Glucose uptake and its effect on gene expression in prochlorococcus.

    Directory of Open Access Journals (Sweden)

    Guadalupe Gómez-Baena

    Full Text Available The marine cyanobacteria Prochlorococcus have been considered photoautotrophic microorganisms, although the utilization of exogenous sugars has never been specifically addressed in them. We studied glucose uptake in different high irradiance- and low irradiance-adapted Prochlorococcus strains, as well as the effect of glucose addition on the expression of several glucose-related genes. Glucose uptake was measured by adding radiolabelled glucose to Prochlorococcus cultures, followed by flow cytometry coupled with cell sorting in order to separate Prochlorococcus cells from bacterial contaminants. Sorted cells were recovered by filtration and their radioactivity measured. The expression, after glucose addition, of several genes (involved in glucose metabolism, and in nitrogen assimilation and its regulation was determined in the low irradiance-adapted Prochlorococcus SS120 strain by semi-quantitative real time RT-PCR, using the rnpB gene as internal control. Our results demonstrate for the first time that the Prochlorococcus strains studied in this work take up glucose at significant rates even at concentrations close to those found in the oceans, and also exclude the possibility of this uptake being carried out by eventual bacterial contaminants, since only Prochlorococcus cells were used for radioactivity measurements. Besides, we show that the expression of a number of genes involved in glucose utilization (namely zwf, gnd and dld, encoding glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and lactate dehydrogenase, respectively is strongly increased upon glucose addition to cultures of the SS120 strain. This fact, taken together with the magnitude of the glucose uptake, clearly indicates the physiological importance of the phenomenon. Given the significant contribution of Prochlorococcus to the global primary production, these findings have strong implications for the understanding of the phytoplankton role in the carbon

  14. Continued glucose output after re-feeding contributes to glucose intolerance in hyperthyroidism.

    OpenAIRE

    Holness, M J; Sugden, M C

    1987-01-01

    The effects of hyperthyroidism to elicit glucose intolerance after glucose administration were decreased under conditions where hepatic glucose output was suppressed. It is concluded that continued hepatic glucose output contributes to abnormal glucose tolerance in hyperthyroidism.

  15. Glucose production for cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S; Karube, I

    1977-04-16

    Glucose was produced from cellulose by passing a cellulose solution through a column of an immobilized cellulase which was prepared by coating an inorganic carrier such as macadam or stainless steel beads with collagen containing the cellulase. Thus, 4 mL of 5% cellulase T-AP (60,000 units/g) solution was dissolved in 100 g of 0.9% collagen solution and the solution mixed with 60 g of macadam (diam. = 0.5 to 1.5 mm) and stirred for 10 min. The treated beads were dried in air at 10/sup 0/ to yield an immobilized enzyme retaining 64% of its activity. Through a column (0.8 x 20 cm) packed with 3 g of the immobilized enzyme, 100 mL of 0.33% Avicel SF solution was circulated at 26.4 mL/min at 30/sup 0/ for 60 h. The Avicel SF conversion to glucose was 23%.

  16. Hepatic glucose utilization in hepatic steatosis and obesity

    OpenAIRE

    Keramida, Georgia; Hunter, James; Peters, Adrien?Michael

    2016-01-01

    Hepatic steatosis is associated with obesity and insulin resistance. Whether hepatic glucose utilization rate (glucose phosphorylation rate; MRglu) is increased in steatosis and/or obesity is uncertain. Our aim was to determine the separate relationships of steatosis and obesity with MRglu. Sixty patients referred for routine PET/CT had dynamic PET imaging over the abdomen for 30?min post-injection of F-18-fluorodeoxyglucose (FDG), followed by Patlak?Rutland graphical analysis of the liver us...

  17. Chapter 10: Glucose control: insulin therapy*

    African Journals Online (AJOL)

    Insulin and its analogues lower blood glucose by stimulating peripheral glucose uptake, especially by skeletal muscle and fat, and by inhibiting hepatic glucose production. Insulin inhibits ... control on 2 or 3 oral glucose lowering drugs.

  18. Is Low Blood Glucose (Hypoglycemia) Dangerous?

    Science.gov (United States)

    ... pills. In general, hypoglycemia is defined as a blood glucose level below 70 mg/dl. Low blood glucose is ... glucose. Always carry carbohydrate foods for treatment. Check blood glucose levels again in 15 minutes, and repeat treatment if ...

  19. Modeling error and apparent isotope discrimination confound estimation of endogenous glucose production during euglycemic glucose clamps

    International Nuclear Information System (INIS)

    Finegood, D.T.; Bergman, R.N.; Vranic, M.

    1988-01-01

    We previously demonstrated that conventional tracer methods applied to euglycemic-hyperinsulinemic glucose clamps result in substantially negative estimates for the rate of endogenous glucose production, particularly during the first half of 180-min clamps. We also showed that addition of tracer to the exogenous glucose infusate resulted in nonnegative endogenous glucose production (Ra) estimates. In this study, we investigated the underlying cause of negative estimates of Ra from conventional clamp/tracer methods and the reason for the difference in estimates when tracer is added to the exogenous glucose infusate. We performed euglycemic-hyperinsulinemic (300-microU/ml) clamps in normal dogs without (cold GINF protocol, n = 6) or with (hot GINF protocol, n = 6) tracer (D-[3-3H]glucose) added to the exogenous glucose infusate. In the hot GINF protocol, sufficient tracer was added to the exogenous glucose infusate such that arterial plasma specific activity (SAa) did not change from basal through the clamp period (P greater than .05). In the cold GINF studies, plasma SAa fell 81 +/- 2% from the basal level by the 3rd h of clamping. We observed a significant, transient, positive venous-arterial difference in specific activity (SAv-SAa difference) during the cold GINF studies. The SAv-SAa difference reached a peak of 27 +/- 6% at 30 min and diminished to a plateau of 7 +/- 1% between 70 and 180 min. We also observed a positive but constant SAv-SAa difference (4.6 +/- 0.2% between 10 and 180 min) during the hot GINF studies

  20. Natural Products as Lead Compounds for Sodium Glucose Cotransporter (SGLT) Inhibitors.

    Science.gov (United States)

    Blaschek, Wolfgang

    2017-08-01

    Glucose homeostasis is maintained by antagonistic hormones such as insulin and glucagon as well as by regulation of glucose absorption, gluconeogenesis, biosynthesis and mobilization of glycogen, glucose consumption in all tissues and glomerular filtration, and reabsorption of glucose in the kidneys. Glucose enters or leaves cells mainly with the help of two membrane integrated transporters belonging either to the family of facilitative glucose transporters (GLUTs) or to the family of sodium glucose cotransporters (SGLTs). The intestinal glucose absorption by endothelial cells is managed by SGLT1, the transfer from them to the blood by GLUT2. In the kidney SGLT2 and SGLT1 are responsible for reabsorption of filtered glucose from the primary urine, and GLUT2 and GLUT1 enable the transport of glucose from epithelial cells back into the blood stream.The flavonoid phlorizin was isolated from the bark of apple trees and shown to cause glucosuria. Phlorizin is an inhibitor of SGLT1 and SGLT2. With phlorizin as lead compound, specific inhibitors of SGLT2 were developed in the last decade and some of them have been approved for treatment mainly of type 2 diabetes. Inhibition of SGLT2 eliminates excess glucose via the urine. In recent times, the dual SGLT1/SGLT2 inhibitory activity of phlorizin has served as a model for the development and testing of new drugs exhibiting both activities.Besides phlorizin, also some other flavonoids and especially flavonoid enriched plant extracts have been investigated for their potency to reduce postprandial blood glucose levels which can be helpful in the prevention and supplementary treatment especially of type 2 diabetes. Georg Thieme Verlag KG Stuttgart · New York.