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1

PET measurement of glucose membrane transport using labeled analogs: Distinction of transport from metabolic processes  

International Nuclear Information System (INIS)

Carrier mediated glucose transport rates across brain capillary and myocardial cell membranes are many times higher than those expected for simple diffusion, and transport regulation can be an important determinant of tissue metabolic status. The authors have investigated the use of glucose analogs and dynamic positron tomography for the non-invasive measurement of unidirectional membrane transport rates. If analog extraction is sufficiently low, transport rates can be inferred directly from fitted kinetic rate constants. Fitting calculations were seen to be sensitive to the difficult to measure rapid components of the arterial input curves, to contributions from blood-borne label in the early data points, and to interference from other chemical forms in cases of significant phosphorylation. This last uncertainty was studied using serial scans of normal brain after venous injection of the well-transported but poorly phosphorylated analog 3-deoxy-3-fluoroglucose. Transport rate constants derived from 4-parameter fits of three hours of data were compared to those derived from 2-parameter fits of the first 12-20 minutes of data. Errors due to trapped label were absorbed primarily into the apparent distribution volume, allowing accurate estimation of transport rate constants from a brief data acquisition period. The study of the distinction of transport from phosphorylation also bears on the important question of the significance of the individual rate constants in the foof the individual rate constants in the four-parameter fitting of brief dynamic scan sequences in studies of metabolic rate using 2-deoxy-2-fluoroglucose

2

Liver kinetics of glucose analogs measured in pigs by PET: importance of dual-input blood sampling.  

DEFF Research Database (Denmark)

Metabolic processes studied by PET are quantified traditionally using compartmental models, which relate the time course of the tracer concentration in tissue to that in arterial blood. For liver studies, the use of arterial input may, however, cause systematic errors to the estimated kinetic parameters, because of ignorance of the dual blood supply from the hepatic artery and the portal vein to the liver. METHODS: Six pigs underwent PET after [15O]carbon monoxide inhalation, 3-O-[11C]methylglucose (MG) injection, and [18F]FDG injection. For the glucose scans, PET data were acquired for 90 min. Hepatic arterial and portal venous blood samples and flows were measured during the scan. The dual-input function was calculated as the flow-weighted input. RESULTS: For both MG and FDG, the compartmental analysis using arterial input led to systematic underestimation of the rate constants for rapid blood-tissue exchange. Furthermore, the arterial input led to absurdly low estimates for the extracellular volume compared with the independently measured hepatic blood volume of 0.25 +/- 0.01 mL/mL (milliliter blood per milliliter liver tissue). In contrast, the use of a dual-input function provided parameter estimates that were in agreement with liver physiology. Using the dual-input function, the clearances into the liver cells (K1 = 1.11 +/- 0.11 mL/min/mL for MG; K1 = 1.07 +/- 0.19 mL/min/mL for FDG) were comparable with the liver blood flow (F = 1.02 +/- 0.05 mL/min/mL). As required physiologically, the extracellular volumes estimated using the dual-input function were larger than the hepatic blood volume. The linear Gjedde-Patlak analysis produced parameter estimates that were unaffected by the choice of input function, because this analysis was confined to time scales for which the arterial-input and dual-input functions were very similar. CONCLUSION: Compartmental analysis of MG and FDG kinetics using dynamic PET data requires measurements of dual-input activity concentrations. Using the dual-input function, physiologically reasonable parameter estimates of K1, k2, and Vp were obtained, whereas the use of conventional arterial sampling underestimated these parameters compared with independent measurements of hepatic flow and hepatic blood volume. In contrast, the linear Gjedde-Patlak analysis, being less informative but more robust, gave similar parameter estimates (K, V) with both input functions. Udgivelsesdato: 2001-May

Munk, O L; Bass, L

2001-01-01

3

Biological basis of tumor imaging with radiolabeled glucose analogs  

International Nuclear Information System (INIS)

Accelerated tumor glycolysis may form the basis for nuclear imaging of tumors with gamma or positron labeled glucose analogs: /sup 18/F-fluorodeoxy-glucose (FDG) or /sup 11/C-deoxyglucose (DG). FDG may be preferable because it crosses some cell membranes more readily than DG, while the latter is a better substrate for glucose hexokinase, the enzyme which phosphorylates the analog to an intermediate trapped in the cell. /sup 14/C-DG and /sup 3/H-FDG were compared in biodistribution studies in C3H mice bearing RIF-1 tumors. The two compounds are cleared very similarly from the blood. At times up to 60 min after injection, tumor, brain, and heart concentrated more /sup 3/H-FDG than /sup 14/C-DG, while liver concentrated more /sup 14/C-DG. Tumor:blood and tumor:liver ratios were higher for /sup 3/H-FDG than for /sup 14/C-DG while tumor:lung ratios were similar. These factors are critical to imaging primary tumors or metastases in these common target organs. Because /sup 18/F-FDG and /sup 3/H-FDG are labeled in different positions, the former is being investigated to see if it retains the superiority of the tritiated compound. Because glycolysis is radioresistant, irradiated and control RIF-1 tumors are being compared to determine if doomed as well as surviving cells will readily concentrate glucose analogs

4

Raman spectroscopy for noninvasive glucose measurements  

OpenAIRE

We report the first successful study of the use of Raman spectroscopy for quantitative, noninvasive (“transcutaneous”) measurement of blood analytes, using glucose as an example. As an initial evaluation of the ability of Raman spectroscopy to measure glucose transcutaneously, we studied 17 healthy human subjects whose blood glucose levels were elevated over a period of 2–3 h using a standard glucose tolerance test protocol. During the test, 461 Raman spectra were collected transcutaneo...

Enejder, Annika M. K.; Scecina, Thomas G.; Oh, Jeankun; Hunter, Martin; Shih, Wei-chuan; Sasic, Slobodan; Horowitz, Gary L.; Feld, Michael S.

2004-01-01

5

Analog to Digital Conversion in Physical Measurements  

OpenAIRE

There exist measuring devices where an analog input is converted into a digital output. Such converters can have a nonlinear internal dynamics. We show how measurements with such converting devices can be understood using concepts from symbolic dynamics. Our approach is based on a nonlinear one-to-one mapping between the analog input and the digital output of the device. We analyze the Bernoulli shift and the tent map which are realized in specific analog/digital converters....

Kapitaniak, T.; Zyczkowski, K.; Feudel, U.; Grebogi, C.

1999-01-01

6

Positron emission tomographic measurements of cerebral glucose utilization using [1-11C]D-glucose  

International Nuclear Information System (INIS)

Regional CMRglc was measured in seven healthy volunteers with positron emission tomography using [1-11C]D-glucose. Regional CBF was measured using [11C]fluoromethane. The arteriovenous differences of unlabeled glucose and oxygen together with 11C metabolites were also measured. In addition to the loss of [11C]CO2, a loss of acidic 11C metabolites was also detected. A three-compartment model was applied to the tracer data in the time interval 0-24 min. After correction for the loss of 11C metabolites, the tracer method gave an average CMRglc of 26.4 +/- 1.9 (SD) mumol/100 g/min, close to the value obtained with the Fick principle. After correction for the loss of [11C]CO2 only, the tracer method gave 23.6 +/- 2.1 mumol/100 g/min, compatible with (1/6) CMRO2, obtained with the Fick principle. These results and the time course of the loss of acidic 11C metabolites are consistent with the presence of nonoxidative metabolism of glucose that causes an early loss of mainly [11C]lacetate after a bolus injection of the tracer. This implies that [1-11C]D-glucose measures the rate of glucose oxidation rather than the total CMRglc. The experiments using [1-11C]D-glucose were compared to five analogous experiments using [U-11C]D-glucose together with [15O]H2O as a flow tracer. After correction for the loss of [11C]CO2, the two glucose tracers gave similar global values of CMRglc and other parameters associated with glucose utilization, but with labeling in the carbon-1 position, t with labeling in the carbon-1 position, the loss of [11C]CO2 was substantially delayed and the contrast between gray and white matter was improved

7

Analog to Digital Conversion in Physical Measurements  

CERN Document Server

There exist measuring devices where an analog input is converted into a digital output. Such converters can have a nonlinear internal dynamics. We show how measurements with such converting devices can be understood using concepts from symbolic dynamics. Our approach is based on a nonlinear one-to-one mapping between the analog input and the digital output of the device. We analyze the Bernoulli shift and the tent map which are realized in specific analog/digital converters. Furthermore, we discuss the sources of errors that are inevitable in physical realizations of such systems and suggest methods for error reduction.

Kapitaniak, T; Feudel, U; Grebogi, C

1999-01-01

8

A Comparative Study on the Antioxidant and Glucose-lowering Effects of Curcumin and Bisdemethoxycurcumin Analog through in vitro Assays  

Directory of Open Access Journals (Sweden)

Full Text Available Type 2 diabetes has emerged as an epidemic affecting millions of people all over the world. Several research findings suggest that oxidative stress is the triggering factor for the development of type 2 diabetes. Hyperglycemia and oxidative stress go hand in hand to accelerate the disease progression in a vicious cycle. In India, the medicinal herb Curcuma longa is used as a culinary food additive and also as a therapeutic agent for diabetes. Recent research evidenced that the curcuminoids present in Curcuma longa have several medicinal properties including anti-diabetic property. However, the bioavailability of curcumin is very less compared to its derivatives and its synthetic analogs. The synthetic analog of bisdemethoxycurcumin is reported to have increased bioavailability and stability but its effect on controlling oxidative stress, glucose absorption and gluconeogenesis have not yet been explored. The aim of this study was to evaluate the anti-oxidant and glucose lowering effects of bisdemethoxycurcumin analog (BDMCA in comparison with curcumin. Anti-oxidant activity of BDMCA and curcumin was evaluated by measuring the rate of inhibition of iron-ascorbate induced lipid peroxidation in liver homogenate in vitro. Effect of these drugs on intestinal glucose absorption in Wistar rats and on gluconeogenesis in liver homogenate in vitro was evaluated to know their glucose lowering effects. We found that both the BDMCA and curcumin lower the gluconeogenesis in the hepatocytes and function as antioxidants in vitro in a similar manner. Both BDMCA and curcumin delays the intestinal glucose absorption but BDMCA delays the intestinal glucose absorption more effectively compared to curcumin.

S. Sivabalan

2010-01-01

9

Measurement of glucose and 2-deoxy-2-[18F]fluoro-D-glucose transport and phosphorylation rates in myocardium using dual-tracer kinetic experiments  

International Nuclear Information System (INIS)

To examine the use of 2-deoxy-2-[18F]fluoro-D-glucose (2-FDG) as a glucose analog for measuring glucose utilization rate in myocardium, dual-tracer kinetic experiments with 2-FDG and 2-[3H]glucose were performed in the perfused, isolated rabbit interventricular septum to measure simultaneously the transport and phosphorylation rates of glucose and 2-FDG. Results of the present study indicated that, in the septum, (i) the transport rate constants of 2-FDG and glucose were similar in magnitude, (ii) the phosphorylation rate constant for 2-FDG was about 60% of that of glucose, (iii) hypoxia caused an increase in phosphorylation rates of glucose and 2-FDG without affecting transport. 9 refs.; 1 figure; 3 tabs

10

Abnormal oral glucose tolerance and glucose malabsorption after vagotomy and pyloroplasty. A tracer method for measuring glucose absorption rates  

International Nuclear Information System (INIS)

The mechanisms underlying the abnormal glucose tolerance in patients who had undergone vagotomy and pyloroplasty were investigated by measuring the rates of absorption of ingested glucose and the clearance rate of glucose using tracer methods. These methods are based on labeling a 100-g oral glucose load with [1-14C]glucose and measuring glucose clearance using plasma levels of infused [3-3H]glucose. The rate of appearance of both ingested and total glucose is then calculated continuously using a two-compartment model of glucose kinetics. It was found that about 30% of the ingested glucose (100 g) failed to appear in the systemic circulation. That this was due to malabsorption was confirmed using breath-hydrogen analysis. The absorption period is short (101 +/- 11 min) compared with normal values but the clearance of glucose is identical to that in control subjects, and it peaks 132 +/- 7 min after glucose loading. The peak plasma insulin values were more than four times higher in patients than in normal subjects, and this may afford an explanation of rates of glucose clearance that are inappropriate for the short absorption period. The combination of glucose malabsorption and this clearance pattern could yield the hypoglycemia that may be observed in patients after gastric surgery

11

Portal glucose infusion-glucose clamp measures hepatic influence on postprandial systemic glucose appearance as well as whole body glucose disposal  

Science.gov (United States)

The full impact of the liver, through both glucose production and uptake, on systemic glucose appearance cannot be readily studied in a classical glucose clamp because hepatic glucose metabolism is regulated not only by portal insulin and glucose levels but also portal glucose delivery (the portal signal). In the present study, we modified the classical glucose clamp by giving exogenous glucose through portal vein, the “portal glucose infusion (PoG)-glucose clamp”, to determine the net hepatic effect on postprandial systemic glucose supply along with the measurement of whole body glucose disposal. By comparing systemic rate of glucose appearance (Ra) with portal glucose infusion rate (PoGinf), we quantified “net hepatic glucose addition (NHGA)” in the place of endogenous glucose production determined in a regular clamp. When PoG-glucose clamps (n = 6) were performed in dogs at basal insulinemia and hyperglycemia (?150 mg/dl, portal and systemic), we measured consistently higher Ra than PoGinf (4.2 ± 0.6 vs. 2.9 ± 0.6 mg·kg?1·min?1 at steady state, P < 0.001) and thus positive NHGA at 1.3 ± 0.1 mg·kg?1·min?1, identifying net hepatic addition of glucose to portal exogenous glucose. In contrast, when PoG-glucose clamps (n = 6) were performed at hyperinsulinemia (?250 pmol/l) and systemic euglycemia (portal hyperglycemia due to portal glucose infusion), we measured consistently lower Ra than PoGinf (13.1 ± 2.4 vs. 14.3 ± 2.4 mg·kg?1·min?1, P < 0.001), and therefore negative NHGA at ?1.1 ± 0.1 mg·kg?1·min?1, identifying a switch of the liver from net production to net uptake of portal exogenous glucose. Steady-state whole body glucose disposal was 4.1 ± 0.5 and 13.0 ± 2.4 mg·kg?1·min?1, respectively, determined as in a classical glucose clamp. We conclude that the PoG-glucose clamp, simulating postprandial glucose entry and metabolism, enables simultaneous assessment of the net hepatic effect on postprandial systemic glucose supply as well as whole body glucose disposal in various animal models (rodents, dogs, and pigs) with established portal vein catheterization. PMID:19934401

Zheng, Dan; Ionut, Viorica; Mooradian, Vahe; Stefanovski, Darko

2010-01-01

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The Effects of a GLP-1 Analog on Glucose Homeostasis in Type 2 Diabetes Mellitus Quantified by an Integrated Glucose Insulin Model  

Science.gov (United States)

In recent years, several glucagon-like peptide-1 (GLP-1)-based therapies for the treatment of type 2 diabetes mellitus (T2DM) have been developed. The aim of this work was to extend the semimechanistic integrated glucose-insulin model to include the effects of a GLP-1 analog on glucose homeostasis in T2DM patients. Data from two trials comparing the effect of steady-state liraglutide vs. placebo on the responses of postprandial glucose and insulin in T2DM patients were used for model development. The effect of liraglutide was incorporated in the model by including a stimulatory effect on insulin secretion. Furthermore, for one of the trials an inhibitory effect on glucose absorption was included to account for a delay in gastric emptying. As other GLP-1 receptor agonists have similar modes of action, it is believed that the model can also be used to describe the effect of other receptor agonists on glucose homeostasis.

Røge, RM; Klim, S; Ingwersen, SH; Kjellsson, MC; Kristensen, NR

2015-01-01

13

Glucose-l-13C as a tracer for the measurement of systemic glucose production  

International Nuclear Information System (INIS)

Glucose-1-13C was used as a tracer for the quantitative measurement of systemic glucose production in 4 dogs and one human subject. The C-1 carbon atom of glucose was extracted as CO2 by enzymatic decarboxylation of glucose with coupled hexokinase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities. The 13C/12C ratio of the CO2 was measured using a magnetic deflection, double collector, mass spectrometer. The methods were checked in three normal and one diabetic dog by infusing glucose-1-14C and glucose-1-13C simultaneously according to the prime-constant-infusion technique. The systemic glucose production rates measured by the two methods were similar. Systemic glucose production rate was also measured in one normal adult man by infusing glucose-1-13C at the rate of 5.4 ?g/kg min following a prime injection of 22.8 mg. The calculated glucose production rate was 2.1 mg/kg min which is similar to results from previous radioisotope dilution studies in man

14

Thermal Conductivity Measurements on consolidated Soil Analogs  

Science.gov (United States)

Heat transport in porous media such as soils and regolith is significantly reduced compared to the properties of compact samples of the same material. The bottle neck for solid state heat transport is the contact area between adjacent grains. For "dry" and unconsolidated materials the contact areas and thus the thermal conductivity are extremely small. Sintering and cementation are two processes that can increase the cross section of interstitial bonds signifcantly. On Mars, cementation can be caused by condensation of water or carbon dioxide ice from the vapor phase, or from salts and minerals that fall out from aqueous solutions. We produced several artificially cemented samples, using small glass beads of uniform size as soil analog. The cementation is achieved by initially molten wax that is mixed with the glass beads while liqiud. The wax freezes preferably at the contact points between grains, thus minimizing surface energy, and consolidates the samples. The thermal conductivity of these samples is then measured in vacuum. We present the results of these measurements and compare them with theoretical models. The observed range of thermal conductivity values can explain some, but not all of the variations in thermal intertia that can be seen in TES remote sensing data.

Seiferlin, K.; Heimberg, M.; Thomas, N.

2007-08-01

15

Synthesis of radioiodinated 1-deoxy-nojirimycin derivatives: novel glucose analogs  

International Nuclear Information System (INIS)

Novel lipophilic and neutral glucose analogs, which are potentially useful for tumor imaging, have been developed. They are designed to circumvent Glut-facilitated transport mechanism, and direct the localization by either hexokinase binding or enzyme reactions (phosphorylation) as potential metabolic markers of tumor cells. Syntheses of tetraacetylated N-(3'-iodo-2'-propenyl)-1-deoxy-nojirimycin (11) and N-(3'-iodo-benzyl)-1-deoxy-nojirimycin (14) were achieved by reacting 1-deoxy-nojirimycin with appropriate alkylating agents. The corresponding tri-butyltin derivatives were also prepared as the starting materials for preparation of I-125-labeled compounds for biodistribution study in rats. Biodistribution in rats showed that [123I]14 exhibited a modest initial brain uptake and retention at a later time (0.59, 0.38, 0.30, and 0.30% dose/organ at 2, 30, 60, and 120 min after an intravenous [IV] injection, respectively), whereas [125I]11 displayed a lower brain uptake (0.35, 0.27, 0.20, and 0.18% dose/organ at 2, 30, 60, and 120 min). In addition, compounds with free hydroxyl groups (12 and 13) were also obtained. As expected, after an IV injection, these free hydroxyl compounds showed a dramatic decrease in brain uptake in rats. It appears that both of the acetylated agents (11 and 14), which display higher lipophilicity (partition coefficient [P.C.]=57.9 and 1,462, respectively), can penetrate the blood-brain barrier (BBB) by a simple diffusion brain barrier (BBB) by a simple diffusion mechanism whereas the free hydroxy compounds (12 and 13), with lower lipophilicity ( P.C.=0.43 and 6.8), showed no brain uptake. A similar pair of glucose derivatives, fluorodeoxyglucose (FDG) and tetraacetylated FDG (AFDG), displayed a dramatic difference in brain uptake in rats. While the lipophilic AFDG ( P.C.=3.79) may penetrate the intact BBB, due to its relatively low P.C. value, the first pass extraction due to simple diffusion mechanism may be low (brain uptake at 2 min was 0.68% dose/organ). The FDG itself has a very low lipophilicity ( P.C.=0.22) but it can be taken up into the brain by a glucose transporter mediated mechanism to cross the BBB (brain uptake at 2 min was 2.53% dose/organ). Preliminary data of these glucose derivatives suggest that further studies are needed to elucidate the uptake and retention mechanisms and their potential application as tumor imaging agents

16

Microcalorimetric Measurements of Glucose Metabolism by Marine Bacterium Vibrio alginolyticus  

OpenAIRE

Microcalorimetric measurements of heat production from glucose by Vibrio alginolyticus were made to assess the viability of calorimetry as a technique for studying the metabolism of marine bacteria at organic nutrient concentrations found in marine waters. The results show that the metabolism of glucose by this bacterium can be measured by calorimetry at submicromolar concentrations. A linear correlation between glucose concentration and total heat production was observed over a concentration...

Gordon, Andrew S.; Millero, Frank J.; Gerchakov, Sol M.

1982-01-01

17

Activity of P536, a UDP-glucose analog, against Trypanosoma cruzi  

International Nuclear Information System (INIS)

P536, a UDP-glucose analog which was previously described as an antiviral agent, has a potent and selective activity against the intracellular and extracellular stages of Trypanosoma cruzi in vitro. It had a 50% inhibitory concentration of less than 5 micrograms/ml for T. cruzi extracellular cultured forms (epimastigote) and of 25 micrograms/ml for T. cruzi intracellular forms (amastigote) growing inside J774G8 macrophage-like cells. In contrast, the 50% inhibitory concentration was 100 micrograms/ml or greater for cultured mammalian cells and 180 micrograms/ml for the proliferation of mouse spleen lymphocytes. Furthermore, the addition of P536 (50 micrograms/ml) to T. cruzi-infected J774G8 cells cured the infected macrophages, making them able to grow and function normally. Studies on the mechanism of action of this drug indicated that it inhibited incorporation of [35S]methionine, [3H]thymidine, [3H]mannose, [14C]-N-acetylglucosamine, and [3H]uridine into macromolecules by T. cruzi epimastigotes, the last being the most sensitive

18

Effects of fasting on plasma glucose and prolonged tracer measurement of hepatic glucose output in NIDDM  

International Nuclear Information System (INIS)

We studied the measurement of hepatic glucose output (HGO) with prolonged [3-3H]glucose infusion in 14 patients with non-insulin-dependent diabetes mellitus (NIDDM). Over the course of 10.5 h, plasma glucose concentration fell with fasting by one-third, from 234 +/- 21 to 152 +/- 12 mg/dl, and HGO fell from 2.35 +/- 0.18 to 1.36 +/- 0.07 mg . kg-1 . min-1 (P less than .001). In the basal state, HGO and glucose were significantly correlated (r = 0.68, P = .03), and in individual patients, HGO and glucose were closely correlated as both fell with fasting (mean r = 0.79, P less than .01). Plasma [3-3H]glucose radioactivity approached a steady state only 5-6 h after initiation of the primed continuous infusion, and a 20% overestimate of HGO was demonstrated by not allowing sufficient time for tracer labeling of the glucose pool. Assumption of steady-state instead of non-steady-state kinetics in using Steele's equations to calculate glucose turnover resulted in a 9-24% overestimate of HGO. Stimulation of glycogenolysis by glucagon injection demonstrated no incorporation of [3-3H]glucose in hepatic glycogen during the prolonged tracer infusion. In a separate study, plasma glucose was maintained at fasting levels (207 +/- 17 mg/dl) for 8 h with the glucose-clamp technique. Total glucose turnover rates remained constant during this prolonged tracer infusion. However, HGO fell to 30% of the basal value simply by maintaining fasting hyperglycemisimply by maintaining fasting hyperglycemia in the presence of basal insulin levels

19

Effects of fasting on plasma glucose and prolonged tracer measurement of hepatic glucose output in NIDDM  

Energy Technology Data Exchange (ETDEWEB)

We studied the measurement of hepatic glucose output (HGO) with prolonged (3-/sup 3/H)glucose infusion in 14 patients with non-insulin-dependent diabetes mellitus (NIDDM). Over the course of 10.5 h, plasma glucose concentration fell with fasting by one-third, from 234 +/- 21 to 152 +/- 12 mg/dl, and HGO fell from 2.35 +/- 0.18 to 1.36 +/- 0.07 mg . kg-1 . min-1 (P less than .001). In the basal state, HGO and glucose were significantly correlated (r = 0.68, P = .03), and in individual patients, HGO and glucose were closely correlated as both fell with fasting (mean r = 0.79, P less than .01). Plasma (3-/sup 3/H)glucose radioactivity approached a steady state only 5-6 h after initiation of the primed continuous infusion, and a 20% overestimate of HGO was demonstrated by not allowing sufficient time for tracer labeling of the glucose pool. Assumption of steady-state instead of non-steady-state kinetics in using Steele's equations to calculate glucose turnover resulted in a 9-24% overestimate of HGO. Stimulation of glycogenolysis by glucagon injection demonstrated no incorporation of (3-/sup 3/H)glucose in hepatic glycogen during the prolonged tracer infusion. In a separate study, plasma glucose was maintained at fasting levels (207 +/- 17 mg/dl) for 8 h with the glucose-clamp technique. Total glucose turnover rates remained constant during this prolonged tracer infusion. However, HGO fell to 30% of the basal value simply by maintaining fasting hyperglycemia in the presence of basal insulin levels.

Glauber, H.; Wallace, P.; Brechtel, G.

1987-10-01

20

Microcalorimetric Measurements of Glucose Metabolism by Marine Bacterium Vibrio alginolyticus  

Science.gov (United States)

Microcalorimetric measurements of heat production from glucose by Vibrio alginolyticus were made to assess the viability of calorimetry as a technique for studying the metabolism of marine bacteria at organic nutrient concentrations found in marine waters. The results show that the metabolism of glucose by this bacterium can be measured by calorimetry at submicromolar concentrations. A linear correlation between glucose concentration and total heat production was observed over a concentration range of 8 mM to 0.35 ?M. It is suggested that these data indicate a constant efficiency of metabolism for this bacterium over the wide range of glucose concentrations studied. PMID:16346131

Gordon, Andrew S.; Millero, Frank J.; Gerchakov, Sol M.

1982-01-01

21

Investigation of the specificity of Raman spectroscopy in non-invasive blood glucose measurements.  

Science.gov (United States)

Although several in vivo blood glucose measurement studies have been performed by different research groups using near-infrared (NIR) absorption and Raman spectroscopic techniques, prospective prediction has proven to be a challenging problem. An important issue in this case is the demonstration of causality of glucose concentration to the spectral information, especially as the intrinsic glucose signal is smaller compared with that of the other analytes in the blood-tissue matrix. Furthermore, time-dependent physiological processes make the relation between glucose concentration and spectral data more complex. In this article, chance correlations in Raman spectroscopy-based calibration model for glucose measurements are investigated for both in vitro (physical tissue models) and in vivo (animal model and human subject) cases. Different spurious glucose concentration profiles are assigned to the Raman spectra acquired from physical tissue models, where the glucose concentration is intentionally held constant. Analogous concentration profiles, in addition to the true concentration profile, are also assigned to the datasets acquired from an animal model during a glucose clamping study as well as a human subject during an oral glucose tolerance test. We demonstrate that the spurious concentration profile-based calibration models are unable to provide prospective predictions, in contrast to those based on actual concentration profiles, especially for the physical tissue models. We also show that chance correlations incorporated by the calibration models are significantly less in Raman as compared to NIR absorption spectroscopy, even for the in vivo studies. Finally, our results suggest that the incorporation of chance correlations for in vivo cases can be largely attributed to the uncontrolled physiological sources of variations. Such uncontrolled physiological variations could either be intrinsic to the subject or stem from changes in the measurement conditions. PMID:21509482

Dingari, Narahara Chari; Barman, Ishan; Singh, Gajendra P; Kang, Jeon Woong; Dasari, Ramachandra R; Feld, Michael S

2011-07-01

22

Synthesis and characterization of 1-deoxy-?-D-glucopyranosyl-methanephosphonyl-5'-uridine monophosphate: a phosphono analog of UDP-glucose  

International Nuclear Information System (INIS)

The phosphono analog of UDP-glucose (UDPG) has been synthesized as a first entry into potential dead-end inhibitors of glycosyltransferases using UDP-sugars such as UDP-glucuronyltransferase and possible alternative substrates for UDPG dehydrogenase and epimerase. 1-Deoxy-?-D-glucopyranosylmethanephosphonate (G-1-CH2P) was synthesized by modifications of literature procedures and characterized by 1H, 31P and 13C NMR. Condensation of G-1-CH2P with UMP morpholidate gave the expected phosphono analog of UDPG (UDPCH2G) in low yield. G-1-CH2P was found to be a substrate for UTP: glucose-1-phosphate pyrophosphoyrlase. Thus, UDPCH2G can be prepared enzymatically from G-1-CH2P and UTP by the coupled action of the pyrophosphoyrlase and inorganic pyrophosphatase. Preliminary evidence suggests UDPCH2G is a very poor substrate for UDPG dehydrogenase. Thus, efficient enzymatic synthesis of the phosphono analog (UDPCH2GA) of UDP-glucuronate appears unlikely

23

Double-label autoradiographic deoxyglucose method for sequential measurement of regional cerebral glucose utilization.  

Science.gov (United States)

A new double-label autoradiographic glucose analog method for the sequential measurement of altered regional cerebral metabolic rates for glucose in the same animal is presented. This method is based on the sequential injection of two boluses of glucose tracer labeled with two different isotopes (short-lived 18F and long-lived 3H, respectively). An operational equation is derived which allows the determination of glucose utilization for the time period before the injection of the second tracer; this equation corrects for accumulation and loss of the first tracer from the metabolic pool occurring after the injection of the second tracer. An error analysis of this operational equation is performed. The double-label deoxyglucose method is validated in the primary somatosensory ("barrel") cortex of the anesthetized rat. Two different rows of whiskers were stimulated sequentially in each rat; the two periods of stimulation were each preceded by an injection of glucose tracer. After decapitation, dried brain slices were first exposed, in direct contact, to standard X-ray film and then to uncoated, "tritium-sensitive" film. Results show that the double-label deoxyglucose method proposed in this paper allows the quantification and complete separation of glucose utilization patterns elicited by two different stimulations sequentially applied in the same animal. The double-label deoxyglucose is of potential usefulness in sensory physiology since it makes possible the separate mapping of regional cerebral glucose utilization patterns elicited by two sequentially applied sensory stimulations in the same animal. The method allows the quantification of a step-like change in regional cerebral glucose utilization in the same animal. It could be used to study the cerebral metabolic effects induced by neuropharmacological agents or surgical interventions applied during the experiment. Using each animal as its own control eliminates intersubject variability. Thus experimental cost and effort can be saved, and the reliability of the results obtained can be increased. PMID:3670600

Redies, C; Diksic, M; Evans, A C; Gjedde, A; Yamamoto, Y L

1987-08-01

24

Blood-brain transport of new glucose analogs and their effect on yeast hexokinase  

International Nuclear Information System (INIS)

Dihalogen derivates of D-glucal were formed by the direct addition of halogen to the unsaturated double-bond between C atoms 1 and 2 in D-glucal. 82Br-glucal and 36Cl-glucal were injected into the carotid artery of rats and brain uptake studied and compared with uptake for D-glucose and 2-deoxy-D-glucose. Investigations with enzymes have shown D-glucal dihalides to be good substrates for hexokinase. (U.K.)

25

Contribution to a decision making model for analogical measurement validation  

International Nuclear Information System (INIS)

In limits of studies taken on validity of analogic measures in nuclear power plant's operation, the present thesis takes aim at establishment of a model to reaching a decision on the indice of probability on measures obtained by preliminary validation system. In a first step, it is proposed to retain a system made by redundant measures in which the calcul of measures is based on the coherence between measures themselves and logic vote. In the second step, one equation is proposed to compute the index of probability of measures taken in account, the characteristics of the system

26

Fluorescence lifetime measurements of boronate derivatives to determine glucose concentration  

Energy Technology Data Exchange (ETDEWEB)

A novel investigation into the fluorescence lifetimes of molecules, both established and newly designed, was performed. These molecules are the basis of a continuous, minimally invasive, glucose sensor based on fluorescence lifetime measurements. This sensor, if coupled with an automated insulin delivery device, would effectively create an artificial pancreas allowing for the constant monitoring and control of glucose levels in a person with diabetes. The proposed sensor includes a fluorescent molecule that changes its' fluorescence properties upon binding selectively and reversibly to glucose. One possible sensor molecule is N-methyl-N-(9-methylene anthryl)-2-methylenephenylboronic acid (AB). The fluorescence intensity of AB was shown to change in response to changing glucose concentrations. (James, 1994) James proposed that when glucose binds to AB the fluorescence intensity increases due to an enhancement of the N{yields}B dative bond which prevents photoinduced electron transfer (PET). PET from the amine (N) to the fluorophore (anthracene) quenches the fluorescence. The dative bond between the boron and the amine can prevent PET by involving the lone pair of electrons on the amine in interactions with the boron rather than allowing them to be transferred to the fluorophore. Results of this research show the average fluorescence lifetime of AB also changes with glucose concentration. It is proposed that fluorescence is due to two components: (1) AB with an enhanced N{yields}B interaction, and no PET, and (2) AB with a weak N{yields}B interaction, resulting in fluorescence quenching by PET. Lifetime measurements of AB as a function of both the pH of the solvent and glucose concentration in the solution were made to characterize this two component system and investigate the nature of the N{yields}B bond. Measurements of molecules similar to AB were also performed in order to isolate behavior of specific AB constituents. These molecules are 9-(Methylaminomethyl)-anthracene (MAMA), and N-benzyl-N-methyl-N-methyl anthracene (AB-B). Fluorescence lifetime measurements confirmed the two species of AB, with and without PET. Fluorescence lifetimes were approximately 11 nsec without PET and 3 nsec with PET. The degree of the interaction between the N and the B atoms was also determined by fluorescence lifetime measurements. Electron transfer rates of AB were measured to be on the order of 10{sup 8} sec{sup -1}. Analysis of AB as a glucose sensor shows it has the potential for measuring glucose concentrations in solution with less than 5% error. Two novel glucose sensing molecules, Chloro-oxazone boronate (COB) and Napthyl-imide boronate (NIB), were synthesized. Both molecules have a N{yields}B dative bond similar to AB, but with longer wavelength fluorophores. COB and NIB were found to be unacceptable for use as glucose sensor molecules due to the small changes in average fluorescence lifetime.

Gable, J H

2000-06-01

27

Noninvasive blood glucose measurement using multiple laser diodes  

Science.gov (United States)

In the event of diabetes clinicians have advocated that frequent monitoring of a diabetic's blood glucose level is the key to avoid future complications (kidney failure, blindness, amputations, premature death, etc.,) associated with the disease. While the test-strip glucose meters available in current consumer markets allow for frequent monitoring, a more convenient technique that is accurate, painless and sample-free is preferable in a diabetic's daily routine. This paper presents a non-invasive blood glucose measurement technique using diffuse reflectance near infrared (NIR) signals. This technique uses a set of laser diodes, each operating at fixed wavelengths in the first overtone region. The NIR signals from the laser diodes are channeled to the measurement site viz., the nail-bed by means of optical fibers. A series of in vivo experiments have been performed on eight normal human subjects using a standard Oral Glucose Tolerance Test (OGTT) protocol. The reflected NIR signals are inputs to a Partial Least Squares (PLS) algorithm for calibration and future predictions. The calibration models used are developed using in vivo datasets and are unique to a particular individual. The 1218 paired points collected from the eight test subjects plotted on the Clarke Error Grid, revealed that 87.3% of these points fall within the A zone while the remainder, within the B zone, both of which, are clinically accepted. The standard error of prediction was +/-13.14mg/dL for the best calibration model. A Bland-Altman analysis of the 1218 paired points yields a 76.3% confidence level for a measurement accuracy of +/-20mg/dL. These results demonstrate the initial potential of the technique for non-invasive blood glucose measurements in vivo.

Ooi, E. T.; Zhang, X. Q.; Chen, J. H.; Soh, P. H.; Ng, K.; Yeo, J. H.

2007-02-01

28

Expression of Human Globular Adiponectin-Glucagon-Like Peptide-1 Analog Fusion Protein and Its Assay of Glucose-Lowering Effect In Vivo  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, human globular adiponectin-glucagon-like peptide-1 analog (gAd-GLP-1-A fusion protein was expressed and its glucose-lowering effect was measured in vivo. We constructed a prokaryotic expression vector PET28a-gAd-GLP-1-A and transformed the vector into Escherichia coli BL21 (DE3. A recombinant fusion protein of about 25KD was expressed from BL21 (DE3 cells after isopropylthio-?-D-galactoside induction. This protein was N-terminal His-tagged gAd-GLP-1-A fusion protein. Most of the protein was expressed in inclusion body. The fusion protein in inclusion body was purified by using High-Affinity Nickel Iminodiacetic Acid Resin and refolded in urea gradient refolding buffer. The refolded protein was incubated with enterokinase to remove the N-terminal His-tag. The fusion protein without His-tag is gAd-GLP-1-A fusion protein, which exhibited significant glucose-lowering effect in diabetic mice.

Tongfeng Zhao, Jing Lv, Jiangpei Zhao, Xiao Huang, Haijuan Xiao

2011-01-01

29

Tunable laser diode system for noninvasive blood glucose measurements.  

Science.gov (United States)

Optical sensing of glucose would allow more frequent monitoring and tighter glucose control for people with diabetes. The key to a successful optical noninvasive measurement of glucose is the collection of an optical spectrum with a very high signal-to-noise ratio in a spectral region with significant glucose absorption. Unfortunately, the optical throughput of skin is low due to absorption and scattering. To overcome these difficulties, we have developed a high-brightness tunable laser system for measurements in the 2.0-2.5 microm wavelength range. The system is based on a 2.3 microm wavelength, strained quantum-well laser diode incorporating GaInAsSb wells and AlGaAsSb barrier and cladding layers. Wavelength control is provided by coupling the laser diode to an external cavity that includes an acousto-optic tunable filter. Tuning ranges of greater than 110 nm have been obtained. Because the tunable filter has no moving parts, scans can be completed very quickly, typically in less than 10 ms. We describe the performance of the present laser system and avenues for extending the tuning range beyond 400 nm. PMID:16390586

Olesberg, Jonathon T; Arnold, Mark A; Mermelstein, Carmen; Schmitz, Johannes; Wagner, Joachim

2005-12-01

30

A noninvasive method to measure splanchnic glucose uptake after oral glucose administration.  

OpenAIRE

We have developed a noninvasive method to estimate splanchnic glucose uptake (SGU) in humans (oral glucose clamp technique [OG-CLAMP]), which combines a hyperinsulinemic clamp with an oral glucose load (oral glucose tolerance test). We validated this method in 12 nondiabetic subjects using hepatic vein catheterization (HVC) during an oral glucose tolerance test. During HVC, splanchnic blood flow increased from 1,395 +/- 64 to 1,935 +/- 109 ml/min, returning to basal after 180 min and accounte...

Ludvik, B.; Nolan, J. J.; Roberts, A.; Baloga, J.; Joyce, M.; Bell, J. M.; Olefsky, J. M.

1995-01-01

31

Effects of gamma-rays and glucose analogs on the energy metabolism of a cell line derived from human cerebral glioma  

International Nuclear Information System (INIS)

Effects of gamma-rays and glucose analogs, 2-deoxy-D-glucose (2-DG), 5-thio-D-glucose (5-TG) and 3-O-methyl glucose (3-O-MG) on cellular energy metabolism have been studied in a cell line, derived from a human cerebral glioma, by analysing intermediates of glycolysis and some important nucleotides (ATP, NAD etc.) using the technique of isotachophoresis. Gamma-irradiation induced a transient decrease in the nucleotide levels accompanied by an accumulation of sugar phosphates, the nucleotide levels recovering in a few hours post-irradiation. 2-DG inhibited glycolysis and reduced the nucleotide levels of irradiated as well as unirradiated cells in a concentration-dependent manner both in presence and absence of respiration, whereas 5-TG and 3-OMG did not show significant effects in the presence of respiration. Reduced energy status observed with 2-DG under respiratory proficient conditions was completely reversed in 2 hr following its removal, whereas such a recovery was not observed in the absence of respiration. These results have important implications in the energy-linked modifications of tumor radiation response using glucose analogs. (author). 36 refs., 6 figs., 4 tabs

32

Capillary bedside blood glucose measurement in neonates: missing a diagnosis of galactosemia.  

Science.gov (United States)

A number of factors may lead to inaccuracy in measurement of capillary blood glucose with a glucometer. Measurement of other carbohydrate molecules such as galactose and fructose along with glucose can potentially be a cause of error. We report a newborn patient who was referred to our hospital with conjugated bilirubinemia, hepatomegaly and high capillary blood glucose levels measured with a glucometer. Simultaneous biochemical measurements revealed normal blood glucose levels. Further investigation led to a diagnosis of classical galactosemia. Capillary blood glucose level measured with glucometer also dropped to normal values following cessation of breastfeeding and initiation of feeding with a lactose-free formula. PMID:25800483

Özbek, Mehmet Nuri; Öcal, Murat; Tanr?verdi, Sibel; Baysal, Birsen; Deniz, Ahmet; Öncel, Kahraman; Demirbilek, Hüseyin

2015-03-01

33

Measurement of Monosaccharides and Conversion of Glucose to Acetate in Anoxic Rice Field Soil  

OpenAIRE

Degradation of glucose has been implicated in acetate production in rice field soil, but the abundance of glucose, the temporal change of glucose turnover, and the relationship between glucose and acetate catabolism are not well understood. We therefore measured the pool sizes of glucose and acetate in rice field soil and investigated the turnover of [U-14C]glucose and [2-14C]acetate. Acetate accumulated up to about 2 mM during days 5 to 10 after flooding of the soil. Subsequently, methanogen...

Chidthaisong, Amnat; Rosenstock, Bernd; Conrad, Ralf

1999-01-01

34

Measuring glucose and fructose-6-phosphate cycling in liver in vivo.  

Science.gov (United States)

Approaches measuring futile cycling of glucose and fructose-6-phosphate (fructose-6-P) in liver in vivo depend on assumptions about the fates of hydrogens bound to specific carbons of glucose. Thus, 3H of [2-3H]glucose has been assumed to be completely removed after its conversion to glucose-6-P, [3-3H]glucose after its conversion to fructose-1,6-bisP, and [6-3H]glucose not at all. Previous measurements have shown that these assumptions are incompletely fulfilled. Corrections to estimates of cycling can be made when detritiations of [2-3H]glucose and [3-3H]glucose are not complete, and detritiation of [6-3H]glucose occurs. How the corrections can be made is presented using data previously reported on giving labeled glucoses to humans after an overnight fast and on infusing a glucose load. Estimates of glucose cycling nearly double, and that of fructose-6-P cycling almost triples. Estimates of hepatic glucose production as measured with [6-3H]glucose decrease. Correction of estimates of cycling under other conditions may very well be similarly affected. Thus, rates of glucose and fructose-6-P cycling appear to be substantially more than previously estimated. Quantitation under a given condition requires measurements to be made of the extent to which assumptions as to the fate of labeled hydrogen of the glucoses are fulfilled. The uncertain extent of exchange of label catalyzed by transaldolase and detritiation in the pentose cycle, the failure of fructose-6-P cycling to be expressed through detritiation of 3H from [3-3H]glucose, and possible isotope effects still limit the confidence that can be placed in such estimates. PMID:8487668

Landau, B R

1993-04-01

35

Development of a fluorescent method for simultaneous measurement of glucose concentrations in interstitial fluid and blood  

International Nuclear Information System (INIS)

Continuous blood glucose monitoring is of great clinical significance to patients with diabetes. One of the effective methods to monitor blood glucose is to measure glucose concentrations of interstitial fluid (ISF). However, a time-delay problem exists between ISF and blood glucose concentrations, which results in difficulty in indicating real-time blood glucose concentrations. Therefore, we developed a fluorescent method to verify the accuracy and reliability of simultaneous ISF and blood glucose measurement, especially incorporating it into research on the delay relationship between blood and ISF glucose changes. This method is based on a competitive reaction among borate polymer, alizarin and glucose. When glucose molecules combine with borate polymers in alizarin–borate polymer competitively, changes in fluorescence intensity demonstrate changes in glucose concentrations. By applying the measured results to the blood and ISF glucose delay relationship, we were able to calculate the time delay as an average of 2.16 ± 2.05 min for ISF glucose changes with reference to blood glucose concentrations. (paper)

36

Development of a fluorescent method for simultaneous measurement of glucose concentrations in interstitial fluid and blood  

Science.gov (United States)

Continuous blood glucose monitoring is of great clinical significance to patients with diabetes. One of the effective methods to monitor blood glucose is to measure glucose concentrations of interstitial fluid (ISF). However, a time-delay problem exists between ISF and blood glucose concentrations, which results in difficulty in indicating real-time blood glucose concentrations. Therefore, we developed a fluorescent method to verify the accuracy and reliability of simultaneous ISF and blood glucose measurement, especially incorporating it into research on the delay relationship between blood and ISF glucose changes. This method is based on a competitive reaction among borate polymer, alizarin and glucose. When glucose molecules combine with borate polymers in alizarin-borate polymer competitively, changes in fluorescence intensity demonstrate changes in glucose concentrations. By applying the measured results to the blood and ISF glucose delay relationship, we were able to calculate the time delay as an average of 2.16 ± 2.05 min for ISF glucose changes with reference to blood glucose concentrations.

Shi, Ting; Li, Dachao; Li, Guoqing; Chen, Limin; Lin, Yuan; Xu, Kexin; Lu, Luo

2013-12-01

37

Novel analog switching circuit for van der Pauw measurements  

OpenAIRE

A simple electronic circuit is described using four common and very inexpensive analog multiplexer/demultiplexer chips. These analog switches are used to select eight different wiring configurations to a van der Pauw sample. Several interfacing schemes to a PC are suggested. The van der Pauw resistivity and Hall voltage expressions are also summarized.

David, T.; Molchadsky, I.; Somechi, A.; Rosenbaum, R.

2005-01-01

38

Relationship between fluctuations in glucose levels measured by continuous glucose monitoring and vascular endothelial dysfunction in type 2 diabetes mellitus  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Fluctuations in blood glucose level cause endothelial dysfunction and play a critical role in onset and/or progression of atherosclerosis. We hypothesized that fluctuation in blood glucose levels correlate with vascular endothelial dysfunction and that this relationship can be assessed using common bedside medical devices. Methods Fluctuations in blood glucose levels were measured over 24?hours by continuous glucose monitoring (CGM on admission day 2 in 57 patients with type 2 diabetes mellitus. The reactive hyperemia index (RHI, an index of vascular endothelial function, was measured using peripheral arterial tonometry (EndoPAT on admission day 3. Results The natural logarithmic-scaled RHI (L_RHI correlated with SD (r=?0.504; PPP=0.001 and percentage of time ?200?mg/dl (r=?0.292; P=0.028. In 12 patients with hypoglycemia, L_RHI also correlated with the percentage of time at hypoglycemia (r=?0.589; P=0.044. L_RHI did not correlate with HbA1c or fasting plasma glucose levels. Furthermore, L_RHI did not correlate with LDL cholesterol, HDL cholesterol, and triglyceride levels or with systolic and diastolic blood pressures. Finally, multivariate analysis identified MAGE as the only significant determinant of L_RHI. Conclusions Fluctuations in blood glucose levels play a significant role in vascular endothelial dysfunction in type 2 diabetes. Trial registration UMIN000007581

Torimoto Keiichi

2013-01-01

39

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)

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 [3H]-2-glucose, an isotope that may undergo futile cycling but does not cycle through glycogen; [14C]-6-glucose, an isotope that may cycle through glycogen but does not futile cycle; and [3H]-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 [14C]-6-glucose (2.3 +/- 0.1 mg X kg-1 X min-1) was greater than that determined with [33H]glucose (2.1 +/- 0.1 mg X kg-1 X min-1, P = 0.002) and slightly less than that determined with [3H]-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 [14C]-6-glucose continued to be less than those determined with [3H]-2-glucose and greater than those seen with [3H]-3-glucose

40

Novel method to differentiate 3T3 L1 cells in vitro to produce highly sensitive adipocytes for a GLUT4 mediated glucose uptake using fluorescent glucose analog  

OpenAIRE

Adipocytes play a vital role in glucose metabolism. 3T3 L1 pre adipocytes after differentiation to adipocytes serve as excellent in vitro models and are useful tools in understanding the glucose metabolism. The traditional approaches adopted in pre adipocyte differentiation are lengthy exercises involving the usage of IBMX and Dexamethasone. Any effort to shorten the time of differentiation and quality expression of functional differentiation in 3T3 L1 cells in terms of enhanced Insulin sensi...

Vishwanath, Divya; Srinivasan, Harini; Patil, Manjunath S.; Seetarama, Sowmya; Agrawal, Sachin Kumar; Dixit, M. N.; Dhar, Kakali

2013-01-01

41

Diffusion of D-glucose measured in the cytosol of a single astrocyte.  

Science.gov (United States)

Astrocytes interact with neurons and endothelial cells and may mediate exchange of metabolites between capillaries and nerve terminals. In the present study, we investigated intracellular glucose diffusion in purified astrocytes after local glucose uptake. We used a fluorescence resonance energy transfer (FRET)-based nano sensor to monitor the time dependence of the intracellular glucose concentration at specific positions within the cell. We observed a delay in onset and kinetics in regions away from the glucose uptake compared with the region where we locally super-fused astrocytes with the D-glucose-rich solution. We propose a mathematical model of glucose diffusion in astrocytes. The analysis showed that after gradual uptake of glucose, the locally increased intracellular glucose concentration is rapidly spread throughout the cytosol with an apparent diffusion coefficient (D app) of (2.38 ± 0.41) × 10(-10) m(2) s(-1) (at 22-24 °C). Considering that the diffusion coefficient of D-glucose in water is D = 6.7 × 10(-10) m(2) s(-1) (at 24 °C), D app determined in astrocytes indicates that the cytosolic tortuosity, which hinders glucose molecules, is approximately three times higher than in aqueous solution. We conclude that the value of D app for glucose measured in purified rat astrocytes is consistent with the view that cytosolic diffusion may allow glucose and glucose metabolites to traverse from the endothelial cells at the blood-brain barrier to neurons and neighboring astrocytes. PMID:23224430

Kreft, Marko; Lukši?, Miha; Zorec, Tomaž M; Prebil, Mateja; Zorec, Robert

2013-04-01

42

Measuring blood glucose in neonatal units: how does hemocue compare?  

OpenAIRE

Rapid and reliable determination of blood glucose concentration is essential during the neonatal period to prevent adverse neurodevelopmental outcome from hypoglycaemia. Despite their unreliability, reagent strip methods continue to be used extensively in neonatal nurseries due to their rapidity and convenience. Recently, a new portable laboratory standard technique has been introduced (HemoCue B-Glucose system) for whole blood glucose determination. It is particularly suitable for near-patie...

Deshpande, S. A.; Matthews, J. N.; Platt, M. P.

1996-01-01

43

Synthesis and characterization of 1-deoxy-. beta. -D-glucopyranosyl-methanephosphonyl-5'-uridine monophosphate: a phosphono analog of UDP-glucose  

Energy Technology Data Exchange (ETDEWEB)

The phosphono analog of UDP-glucose (UDPG) has been synthesized as a first entry into potential dead-end inhibitors of glycosyltransferases using UDP-sugars such as UDP-glucuronyltransferase and possible alternative substrates for UDPG dehydrogenase and epimerase. 1-Deoxy-..beta..-D-glucopyranosylmethanephosphonate (G-1-CH/sub 2/P) was synthesized by modifications of literature procedures and characterized by /sup 1/H, /sup 31/P and /sup 13/C NMR. Condensation of G-1-CH/sub 2/P with UMP morpholidate gave the expected phosphono analog of UDPG (UDPCH/sub 2/G) in low yield. G-1-CH/sub 2/P was found to be a substrate for UTP: glucose-1-phosphate pyrophosphoyrlase. Thus, UDPCH/sub 2/G can be prepared enzymatically from G-1-CH/sub 2/P and UTP by the coupled action of the pyrophosphoyrlase and inorganic pyrophosphatase. Preliminary evidence suggests UDPCH/sub 2/G is a very poor substrate for UDPG dehydrogenase. Thus, efficient enzymatic synthesis of the phosphono analog (UDPCH/sub 2/GA) of UDP-glucuronate appears unlikely.

Andre, J.C.; Mervic, M.; Armstrong, R.N.

1987-05-01

44

Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry  

DEFF Research Database (Denmark)

The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments in connection to in vivo metabolic studies investigating glucose turnover and lipolytic rate. Moreover, in order to keep up with this new fast analysis, simple derivatization procedures have been developed. Prior to analysis, glucose and glycerol were derivatized using benzoyl chloride in order to form benzoylated derivatives via new simplified fast procedures. For glucose, two internal standards were evaluated, [U-(13) C(6)]glucose and [U-(13) C(6), D(7)]glucose, and for glycerol, [U-(13) C(3), D(8)]glycerol was used. The method was validated by means of calibration curves, quality control samples, and plasma samples spiked with [6,6-D(2)]glucose, [U-(13) C(6)]glucose, and [1,1,2,3,3-D(5)]glycerol in order to test accuracy, precision, and recovery of the method. Moreover, post preparative and freeze-thaw sample stability were tested. The correlation of calibration curves for the glucose concentration were r(2) =?0.9998 for [U-(13) C(6)]glucose and r(2) =?0.9996 for [U-(13) C(6), D(7)]glucose, and r(2) =?0.9995 for the glycerol concentration. Interday accuracy for glucose using [U-(13) C(6)]glucose and glycerol determined in spiked plasma were respectively 103.5% and 106.0%, and the coefficients of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14?days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose and glycerol concentrations and enrichment of infused tracers most commonly used in human metabolic kinetic studies.

BornØ, Andreas; Foged, Lene

2014-01-01

45

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

International Nuclear Information System (INIS)

We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered [18F]fluorodeoxyglucose (FDG) and [14C]-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 14C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the 14C 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

46

Investigation of the specificity of Raman spectroscopy in non-invasive blood glucose measurements  

OpenAIRE

Although several in vivo blood glucose measurement studies have been performed by different research groups using near-infrared (NIR) absorption and Raman spectroscopic techniques, prospective prediction has proven to be a challenging problem. An important issue in this case is the demonstration of causality of glucose concentration to the spectral information, especially as the intrinsic glucose signal is smaller compared to that of the other analytes in the blood-tissue matrix. Furthermore,...

Dingari, Narahara Chari; Barman, Ishan; Singh, Gajendra P.; Kang, Jeon Woong; Dasari, Ramachandra R.; Feld, Michael S.

2011-01-01

47

Combined use of basal insulin analog and acarbose reduces postprandial glucose in patients with uncontrolled type 2 diabetes  

Science.gov (United States)

Aims/Introduction Early initiation of basal insulin therapy is recommended for normalizing fasting blood glucose in type 2 diabetes mellitus. However, basal insulin treatment might not adequately control postprandial glucose levels. The present study evaluated whether the combination of the ?-glucosidase inhibitor, acarbose, and basal insulin improved blood glucose control under daily-life treatment conditions in a large sample of Korean patients. Materials and Methods The present study was a multicenter, prospective, observational study under daily-life treatment conditions. A total of 539 patients with type 2 diabetes who were treated with basal insulin and additional acarbose were enrolled and followed up for 20 weeks. Changes in hemoglobin A1c, fasting and postprandial blood glucose were evaluated at baseline and at the end of the observation period. The physician and patient satisfaction of the combination treatment and safety were assessed. Results Hemoglobin A1c decreased by 0.55 ± 1.05% from baseline (P < 0.0001). Fasting and postprandial blood glucose levels were reduced by 0.89 ± 3.79 and 2.59 ± 4.77 mmol/L (both P < 0.0001). The most frequently reported adverse drug reactions were flatulence (0.37%) and abnormal gastrointestinal sounds (0.37%), and all were mild in intensity and transient. In the satisfaction evaluation, 79.0% of physicians and 77.3% of patients were ‘very satisfied’ or ‘satisfied’ with the combined basal insulin and acarbose therapy. Conclusions Combination therapy of basal insulin and acarbose in patients with type 2 diabetes improved glucose control, and had no drug-specific safety concerns, suggesting that the treatment might benefit individuals who cannot control blood glucose with basal insulin alone. PMID:25802730

Kim, Ji-Hyun; Ahn, Ji-Hyun; Kim, Soo-Kyung; Lee, Dae-Ho; Kim, Hye-Soon; Shon, Ho-Sang; Jeon, Hyun-Jeong; Kim, Tae-Hwa; Cho, Yong-Wook; Kim, Jae-Taek; Han, Sung-Min; Chung, Choon-Hee; Ryu, Ohk-Hyun; Lee, Jae-Min; Lee, Soon-Hee; Kwon, Min-Jeong; Kim, Tae-kyun; Namgoong, Il-Seong; Kim, Eun-Sook; Jung, In-Kyung; Moon, Sung-Dae; Han, Je-Ho; Kim, Chong-Hwa; Cho, Eun-Hee; Kim, Ki-Young; Park, Hee-Baek; Lee, Ki-Sang; Lee, Sung-Woo; Lee, Sang-Cheol; Kang, Cheol-Min; Jeon, Byung-Sook; Song, Min-Seop; Yun, Seung-Baik; Chung, Hyung-Keun; Seong, Jong-Ho; Jeong, Jin-Yi; Cha, Bong-Yun

2015-01-01

48

Blood glucose measurement by multiple attenuated total reflection and infrared absorption spectroscopy.  

Science.gov (United States)

The difficulty of measuring physiological concentrations of glucose in blood by conventional infrared absorption spectroscopy is due to the intrinsic high background absorption of water. This limitation can be largely overcome by the use of a CO2 laser as an infrared source in combination with a multiple attenuated total reflection (ATR) technique. To demonstrate the applicability of this technique, we compared in vitro measurements of glucose in blood obtained from an experimental infrared laser spectrometer with independent measurements made by a standard YSI 23A laboratory glucose analyzer. The capability of continuous measurement of blood glucose concentration is of primary importance in the future development of a glucose sensor for diabetic patients. PMID:2345001

Mendelson, Y; Clermont, A C; Peura, R A; Lin, B C

1990-05-01

49

Kromoscopic measurement of glucose in the first overtone region of the near-infrared spectrum  

Science.gov (United States)

The ability of Kromoscopy to measure glucose selectively is demonstrated in solutions composed glucose, urea, triacetin, bovine serum albumin (BSA), cholesterol, and hemoglobin (Hb). Kromoscopic measurements are made with a four-channel instrument designed for measuring light between 1500 and 1900 nm. The channels are configured to respond to four individual bands of near infrared light centered at 1600, 1700, 1750, and 1800 nm. An equation is proposed that describes the relative response for each channel as a function of relevant experimental parameters. This equation predicts the linear response observed for these types of measurements as a function of solute concentration. In addition, molar absorptivities are provided for glucose, urea, triacetin, BSA, Hb, and water. The non-negligible absorptivity of water demands the consideration of water displacement caused by solute dissolution. Channel responses are measured for a series of thirty-one samples. The chemical composition of these samples is designed to minimize the correlations between glucose concentration and the concentrations of all other solutes. Likewise, these samples provide negligible correlation between the concentration of glucose and the extent of water displacement. A calibration model is constructed for glucose by using a conventional P-matrix multiple linear regression analysis of the four-channel information. The resulting model demonstrates selectivity for glucose with values of 1.27 and 1.34 mM for the standard errors of calibration and prediction, respectively, over a glucose concentration range of 1.9 to 19 mM.

Amerov, Airat K.; Sun, Yu; Small, Gary W.; Arnold, Mark A.

2002-05-01

50

Comparison between transmittance and reflectance measurements in glucose determination using near infrared spectroscopy  

Science.gov (United States)

Glucose determination based on near-IR spectroscopy is investigated for reflectance and transmittance measurement. A wavelength range is 1100 to 2500 nm, which includes both the combination and overtone bands of glucose absorption. Intralipid solutions are used as samples, where glucose concentrations vary between 0 and 1000 mg/dl. Sample thickness for reflectance is 10 cm and 1- and 2-mm-thick samples are used for transmission. Partial least-squares regression (PLSR) analyses are performed to predict glucose concentrations. The standard errors of calibration are comparable between reflectance and 2-mm-thick transmittance. The reflectance method is inferior to the transmittance method in terms of the standard errors of prediction. Loading vector analysis for reflectance does not show glucose absorption features. Reflected light may not have enough information of glucose since a major portion of detected light has a short optical path length. In addition, prediction becomes more dependent on medium scattering rather than glucose, compared with transmission measurement. Loading vectors obtained from a PLSR transmittance analysis have glucose absorption profiles. The 1-mm-thick samples give better results than the 2-mm-thick samples for both calibration and prediction models. The transmittance setup is recommended for noninvasive glucose monitoring.

Jeon, Kye J.; Hwang, In D.; Hahn, Sang J.; Yoon, Gilwon

2006-01-01

51

Measurement of Physiologic Glucose Levels Using Raman Spectroscopy in a Rabbit Aqueous Humor Model  

Science.gov (United States)

We have elecited a reliable glucose signature in mammalian physiological ranges using near infrared Raman laser excitation at 785 nm and multivariate analysis. In a recent series of experiments we measured glucose levels in an artificial aqueous humor in the range from 0.5 to 13X normal values.

Lambert, J.; Storrie-Lombardi, M.; Borchert, M.

1998-01-01

52

Review article: glucose measurement in the operating room: more complicated than it seems.  

Science.gov (United States)

Abnormalities of blood glucose are common in patients undergoing surgery, and in recent years there has been considerable interest in tight control of glucose in the perioperative period. Implementation of any regime of close glycemic control requires more frequent measurement of blood glucose, a function for which small, inexpensive, and rapidly responding point-of-care devices might seem highly suitable. However, what is not well understood by many anesthesiologists and other staff caring for patients in the perioperative period is the lack of accuracy of home glucose meters that were designed for self-monitoring of blood glucose by patients. These devices have been remarketed to hospitals without appropriate additional testing and without an appropriate regulatory framework. Clinicians who are accustomed to the high level of accuracy of glucose measurement by a central laboratory device or by an automated blood gas analyzer may be unaware of the potential for harmful clinical errors that are caused by the inaccuracy exhibited by many self-monitoring of blood glucose devices, especially in the hypoglycemic range. Knowledge of the limitations of these meters is essential for the perioperative physician to minimize the possibility of a harmful measurement error. In this article, we will highlight these areas of interest and review the indications, technology, accuracy, and regulation of glucose measurement devices used in the perioperative setting. PMID:20142354

Rice, Mark J; Pitkin, Andrew D; Coursin, Douglas B

2010-04-01

53

In vivo measurements of brain glucose transport using the reversible michaelis-menten model and simultaneous measurements of cerebral blood flow changes during hypoglycemia  

OpenAIRE

Glucose is the major substrate that sustains normal brain function. When the brain glucose concentration approaches zero, glucose transport across the blood-brain barrier becomes rate limiting for metabolism during, for example, increased metabolic activity and hypoglycemia. Steady-state brain glucose concentrations in ?-chloralose anesthetized rats were measured noninvasively as a function of plasma glucose. The relation between brain and plasma glucose was linear at 4.5 to 30 mmol/L plasma...

Choi, I. -y; Lee, S. -p; Kim, S. -g; Gruetter, R.

2001-01-01

54

Impact of repeated measures and sample selection on genome-wide association studies of fasting glucose  

OpenAIRE

Although GWAS have been performed in longitudinal studies, most used only a single trait measure. GWAS of fasting glucose have generally included only normoglycemic individuals. We examined the impact of both repeated measures and sample selection on GWAS in ARIC, a study which obtained four longitudinal measures of fasting glucose and included both individuals with and without prevalent diabetes. The sample included Caucasians and the Affymetrix 6.0 chip was used for genotyping. Sample sizes...

Rasmussen-torvik, Laura J.; Alonso, Alvaro; Li, Man; Kao, Wen; Ko?ttgen, Anna; Yan, Yuer; Couper, David; Boerwinkle, Eric; Bielinski, Suzette J.; Pankow, James S.

2010-01-01

55

Non-Invasive Glucose Measurement by Use of Metabolic Heat Conformation Method  

OpenAIRE

A non-invasive glucose measurement system based on the method of metabolic heat conformation (MHC) is presented in this paper. This system consists of three temperature sensors, two humidity sensors, an infrared sensor and an optical measurement device. The glucose level can be deduced from the quantity of heat dissipation, blood flow rate of local tissue and degree of blood oxygen saturation. The methodology of the data process and the measurement error are also analyzed. The system is appli...

Junfeng Li; Dongsheng Wang; Xiaohao Wang; Fei Tang

2008-01-01

56

Detection accuracy of three glucose meters estimated by capillary blood glucose measurements compared with venous blood evaluated by the diabetes unit of the Hospital Evangélico de Curitiba, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Mirnaluci Paulino Ribeiro Gama, Camile Fiorese Cruzeta, Ana Carolina Ossowski, Marina Rech Bay, Mariella Muller Michaelis, Stênio Lujan CamachoEndocrinology and Diabetes Service, Hospital Universitário Evangélico de Curitiba, BrazilObjective: To compare capillary blood glucose measurements between three different glucose meters and with the serum glucose values of inpatients at the diabetes unit of Hospital Universitário Evangélico de Curitiba, Brazil.Materials and methods: A total of 132 non-intensive care unit patients admitted for medical and surgical pathologies were evaluated. All patients reported a previous diagnosis of diabetes mellitus, were under 60 years of age, had no hematocrit alterations, remained hemodynamically stable during the time of data collection, and were given no ascorbic acid, acetaminophen, dopamine, or mannitol during follow-up. Capillary and serum blood glucose samples were collected simultaneously by finger-stick and venipuncture 2 hours after lunch, by the same observer, who was blinded to the serum glucose results. First, between July and November 2009, capillary glucose levels were measured using the blood glucose meters OneTouch SureStep® and MediSense Optium®. Between November 2009 and February 2010, capillary blood glucose levels were measured on the glucose meters OneTouch SureStep and Optium Xceed®. The capillary glucose readings were analyzed between meters and also in relation to the serum blood glucose values by the t-test for paired samples and the Mood two-sample test.Results: The patients’ mean age was 50.45 years. The blood glucose means obtained using the meters OneTouch SureStep, MediSense Optium, and Optium Xceed were, respectively, 183.87 mg/dL, 178.49 mg/dL, and 192.73 mg/dL, and the mean for the serum glucose values was 174.58 mg/dL. A significant difference was found between the capillary measurements taken by the glucose meters and the serum glucose measurements (P < 0.05, and no significant interdevice difference was found. After stratification of the serum blood glucose values into two groups, below and above 180 mg/dL, the variance found for the glucose meter OneTouch SureStep was statistically greater (P = 0.03 in relation to the serum glucose levels above 180 mg/dL, which was not the case with the glucose meters MediSense Optium (P = 0.06 and Optium Xceed (P = 0.12. The percentage of capillary blood glucose values showing a variation of less than 20% compared with serum values was 64.94% for OneTouch SureStep, 47.83% for Medisense Optium, and 51.61% for Optium Xceed, when serum glucose was greater than 75 mg/dL.Conclusion: The glucose meters tested showed an adequate interdevice correlation in their capillary glucose readings, in addition to correlating with the serum glucose values (ie, if a blood glucose reading is high or low in one test, it is likely to be respectively high or low in another. The means for the capillary blood glucose readings, however, were significantly different from the mean serum glucose. When serum glucose was above 180 mg/dL, there was a greater variance in the capillary measurements on the glucose meter OneTouch SureStep, with less correlation with the serum blood glucose (P < 0.05, which did not occur significantly with the two other glucose meters. On the other hand, OneTouch SureStep had the highest accuracy in relation to serum glucose when the whole sample of serum glucose values above 75 mg/dL was analyzed, considering a variation of less than 20% in the measurements. The three glucose meters provide readings that correlate with the serum glucose values of hospitalized patients. However, one should bear in mind that capillary measurements quite often show more than a 20% variation in relation to serum glucose values, and caution should be exercised in interpreting the readings when serum glucose levels are elevated.Keywords: capillary blood glucose, serum glucose, glucose meters, hospitalized patients

Camacho SL

2012-05-01

57

Two-wavelength carbon dioxide laser application for in-vitro blood glucose measurements.  

Science.gov (United States)

To develop a fast and easy clinical method for glucose measurements on whole blood samples, changes in glucose spectra are investigated varying temperature, glucose concentration, and solvent using attenuated total reflection Fourier transform infrared (ATR- FTIR) measurements. The results show a stability of the spectra at different temperatures and wavelength shifts of the absorption bands when water is replaced by blood. Because the ATR measurements are influenced by sedimentation of the red blood cells, a two-wavelength CO2 laser is used to determine the glucose concentration in whole blood samples. For this purpose, the first laser wavelength lambda(1) is tuned to the maximum of the glucose absorption band in blood at 1080 cm(-1), and the second laser wavelength lambda 2 is tuned to 950 cm(-1) for background measurements. The transmitted laser power through the optical cell containing the whole blood sample at lambda 1 and lambda 2 is used to determine the ratio. This signal correlates well with the glucose concentration in the whole blood samples. The CO2 laser measurement is too fast to be influenced by the red blood cell sedimentation, and will be a suitable method for glucose determination in whole blood. PMID:18315379

Meinke, Martina; Müller, Gehard; Albrecht, Hansjörg; Antoniou, Christina; Richter, Heike; Lademann, Juergen

2008-01-01

58

Preparation and validation of implantable electrodes for the measurement of oxygen and glucose.  

Science.gov (United States)

In realizing the continuous measurement of pO2 and glucose concentration in the subcutaneous tissue, miniaturized electrochemical oxygen- and enzyme glucose sensors, based on modified Clark-type electrodes for transient implantation, were developed and investigated. The electrodes were prepared by means of sequential dipping procedures in glucose oxidase and in different polymer solutions at well-defined environmental conditions in an incubator. By means of combining a hydrophobic membrane with a glucose permeable area and a hydrophilic membrane in the case of the glucose sensor, linearity of the glucose dependent electrode signal up to greater than 20 mmol/l could be achieved. After subcutaneous implantation in the neck of dogs, the enzyme sensor is able to follow glucose profiles in the normo- and in the hyperglycaemic range, e.g. as caused by oral glucose loads. Looking for the difference in sensitivity of the enzyme sensor measured in vitro and calculated from in vivo data, the influence of potential nonspecific, interfering substances in vivo such as urea, amino acids, electrolytes, and albumin was estimated. PMID:2636836

Brunstein, E; Abel, P; Gens, A; Eich, K; Woedtke, T V

1989-01-01

59

A correction method using a support vector machine to minimize hematocrit interference in blood glucose measurements.  

Science.gov (United States)

Point-of-care testing glucose meters are widely used, important tools for determining the blood glucose levels of people with diabetes, patients in intensive care units, pregnant women, and newborn infants. However, a number of studies have concluded that a change in hematocrit (Hct) levels can seriously affect the accuracy of glucose measurements. The aim of this study was to develop an algorithm for glucose calculation with improved accuracy using the Hct compensation method that minimizes the effects of Hct on glucose measurements. The glucose concentrations in this study were calculated with an adaptive calibration curve using linear fitting prediction and a support vector machine, which minimized the bias in the glucose concentrations caused by the Hct interference. This was followed by an evaluation of performance according to the international organization for standardization (ISO) 15197:2013 based on bias with respect to the reference method, the coefficient of variation, and the valid blood samples/total blood samples within the ±20% and 15% error grids. Chronoamperometry was performed to verify the effect of Hct variation and to compare the proposed method. As a result, the average coefficients of variation for chronoamperometry and the Hct compensation method were 2.43% and 3.71%, respectively, while the average biases (%) for these methods were 12.08% and 5.69%, respectively. The results of chronoamperometry demonstrated that a decrease in Hct levels increases glucose concentrations, whereas an increase in Hct levels reduces glucose concentrations. Finally, the proposed method has improved the accuracy of glucose measurements compared to existing chronoamperometry methods. PMID:25033022

Shin, Jaeyeon; Park, Hodong; Cho, Sungpil; Nam, Hakhyun; Lee, Kyoung-Joung

2014-09-01

60

Measurement of deuterium-labeled glucose flux in newborn infants by the continuous isotope infusion technique  

International Nuclear Information System (INIS)

Although hypoglycemia is a frequent neonatal problem, direct estimates of glucose turnover in newborn infants have not been possible before the advent of practical, stable isotope microtechniques. Using the well-established constant isotopic infusion procedure, glucose flux has been measured in newborn infants for the first time with the metabolically non-recycling tracer, glucose-6,6-d2. Nineteen infants from 650 to 4330 grams (25 to 44 weeks gestation) were studied at various times during the first week of postnatal life. 100 to 200 microliter capillary blood samples, obtained at appropriate intervals during the course of a 150 to 240 minute infusion of dideuterioglucose, were processed by rapid ion exchange purification and the glucose converted to the 6-0-acetyl-1,2 : 3,5-di-O-(n-butane-boronyl)-?-D-glucofuranose derivative for subsequent measurement of isotopic enrichment by combined GC-MS with selected ion recording using an AVA:Voltage Sweeping circuit. Glucose flux rates were calculated by steady-state equations, where appropriate, or by non steady-state approximations when blood glucose concentration and/or glucose isotopic enrichment changed during the course of the investigation. Total glucose flux ranged from 3 to 43 mg/min (3.7 to 11.1 mg/kg.min) and was directly correlated with body weight, estimated brain weight, and average blood sugar concentration during the course of the study. These data agree closely with previous indirect estimates ofosely with previous indirect estimates of glucose metabolism in the newborn period and represent the first direct measurements of new glucose production and utilization in the human neonate

61

Cerebral glucose transport and metabolism with dynamic PET  

International Nuclear Information System (INIS)

A comprehensive model describing the response of the steady-state tissue distribution of glucose to changes in plasma glucose concentration was developed. In the model, the steady-state glucose content can be used to predict the steady-state distribution spaces of both phosphorylatable and non-phosphorylatable glucose analogs, and thus the value of the lumped constant (LC) required to convert measured rates of analog metabolism to the desired rate of glucose metabolism. Models of the sensitivity of the kinetic rate constants for phosphorylatable glucose analogs to tissue glucose content were developed. The use of the measured distribution space of a non-phosphorylatable analog such as methyl glucose as an indicator of the LC, is only useful for hyperglycemia. We determined that a particular aspect of the kinetics of phosphorylatable analogs, the ratio of the phosphorylation rate constant to the membrane transport rate constant, is very sensitive to glucose content over the entire physiological range of values. Considerable effort is being made to optimize the use of venous blood that is ''arterialized'' by limb warming methods. Similarly, final refinements have been made to the non-linear least squares fitting routines, allowing for blood-borne radioactivity and for the loss of phosphorylation product

62

Design of a Mechanical-Tunable Filter Spectrometer for Noninvasive Glucose Measurement  

Science.gov (United States)

The development of an accurate and reliable noninvasive near-infrared (NIR) glucose sensor hinges on the success in addressing the sensitivity and the specificity problems associated with the weak glucose signals and the overlapping NIR spectra. Spectroscopic hardware parameters most relevant to noninvasive blood glucose measurement are discussed, which include the optical throughput, integration time, spectral range, and the spectral resolution. We propose a unique spectroscopic system using a continuously rotating interference filter, which produces a signal-to-noise ratio of the order of 10^5 and is estimated to be the minimum required for successful in vivo glucose sensing. Using a classical least-squares algorithm and a spectral range between 2180 and 2312 nm, we extracted clinically relevant glucose concentrations in multicomponent solutions containing bovine serum albumin, triacetin, lactate, and urea.

Saptari, Vidi; Youcef-Toumi, Kamal

2004-05-01

63

Measurement of tissue optical properties with optical coherence tomography: Implication for noninvasive blood glucose concentration monitoring  

Science.gov (United States)

Approximately 14 million people in the USA and more than 140 million people worldwide suffer from diabetes mellitus. The current glucose sensing technique involves a finger puncture several times a day to obtain a droplet of blood for analysis. There have been enormous efforts by many scientific groups and companies to quantify glucose concentration noninvasively using different optical techniques. However, these techniques face limitations associated with low sensitivity, accuracy, and insufficient specificity of glucose concentrations over a physiological range. Optical coherence tomography (OCT), a new technology, is being applied for noninvasive imaging in tissues with high resolution. OCT utilizes sensitive detection of photons coherently scattered from tissue. The high resolution of this technique allows for exceptionally accurate measurement of tissue scattering from a specific layer of skin compared with other optical techniques and, therefore, may provide noninvasive and continuous monitoring of blood glucose concentration with high accuracy. In this dissertation work I experimentally and theoretically investigate feasibility of noninvasive, real-time, sensitive, and specific monitoring of blood glucose concentration using an OCT-based biosensor. The studies were performed in scattering media with stable optical properties (aqueous suspensions of polystyrene microspheres and milk), animals (New Zealand white rabbits and Yucatan micropigs), and normal subjects (during oral glucose tolerance tests). The results of these studies demonstrated: (1) capability of the OCT technique to detect changes in scattering coefficient with the accuracy of about 1.5%; (2) a sharp and linear decrease of the OCT signal slope in the dermis with the increase of blood glucose concentration; (3) the change in the OCT signal slope measured during bolus glucose injection experiments (characterized by a sharp increase of blood glucose concentration) is higher than that measured in the glucose clamping experiments (characterized by slow, controlled increase of the blood glucose concentration); and (4) the accuracy of glucose concentration monitoring may substantially be improved if optimal dimensions of the probed skin area are used. The results suggest that high-resolution OCT technique has a potential for noninvasive, accurate, and continuous glucose monitoring with high sensitivity.

Larin, Kirill V.

64

Thermal emission spectroscopy as a tool for noninvasive blood glucose measurements  

Science.gov (United States)

The advanced prototype presented here is based on Thermal Emission Spectroscopy (TES) and promises a new generation of non-invasive human tissue analyte instruments. The method and instrument are based on the discovery that natural mid-infrared emission from the human body, especially from the tympanic membrane, is modulated by the state of the emitting tissue. In a simple experimental arrangement, it was demonstrated that emission from glucose could be detected using room temperature detectors in a filter-based setup. Thermal infrared emission characteristics of different glucose concentrations in human plasma solutions were measured. To our knowledge, this is the first time such measurements are reported. In-vivo measurements demonstrated the reproducibility of the methodology of the non-invasive glucose monitor. The non-invasive measurement was calibrated to the serum glucose concentration using 432-paired measurements and subsequently tested (results of Power Analyses) in a blind fashion with 126-paired measurements from diabetic subjects. Non-invasive glucose results were compared with laboratory reference measurements using Error-in-Variable methods. Clark Error Grid analysis showed that 100% of the measurements fell within zones A and B (90% in zone A and 10% in zone B). The Standard Deviation for all non-invasive measured concentrations is 27 mg/dL, Mean Absolute Relative Error %MARE = 8.6, and the correlation coefficient is r = 0.94. This first independent clinical study of a non-invasive blood glucose prototype has demonstrated glucose measurements with clinically acceptable accuracy without the necessity of individual daily calibration.

Buchert, Janusz M.

2004-08-01

65

Integrated catheter system for continuous glucose measurement and simultaneous insulin infusion.  

Science.gov (United States)

A new measurement system enables combination of continuous glucose monitoring (CGM) and insulin infusion. A sensor system comprising an optical glucose biosensor and an optical oxygen sensor is integrated into the insulin infusion catheter of an insulin pump. Both sensors rely on near infrared (NIR) phosphorescent porphyrin dyes, wherefore the signals can be read out transcutaneous and non-invasively with a custom-built phase fluorometer measurement module. The spectral properties of the indicator dyes and the optical setup of the measurement module were optimized to enable independent read-out in two channels. Dynamic ranges from 0 mmHg to 160 mmHg oxygen and 0mg/dL to 360 mg/dL glucose (LOD 2mg/dL) are covered by the oxygen and the glucose sensor, respectively. In-vivo measurements in pigs demonstrate good correlation of reference blood glucose levels and glucose values obtained with the presented sensor system. The evaluation of the clinical accuracy of the system with Clarke Error Grid Analysis showed similar results to CGM-devices currently on the market. PMID:25194803

Nacht, Barbara; Larndorfer, Christoph; Sax, Stefan; Borisov, Sergey M; Hajnsek, Martin; Sinner, Frank; List-Kratochvil, Emil J W; Klimant, Ingo

2015-02-15

66

In vitro measurements of physiological glucose concentrations in biological fluids using mid-infrared light  

OpenAIRE

Mid-infrared transmission spectroscopy using broadband mid-infrared or Quantum Cascade laser sources is used to predict glucose concentrations of aqueous and serum solutions containing physiologically relevant amounts of glucose (50-400 mg/dL). We employ partial least squares regression to generate a calibration model using a subset of the spectra taken and to predict concentrations from new spectra. Clinically accurate measurements with respect to a Clarke error grid were made for concentrat...

Liakat, Sabbir; Bors, Kevin A.; Huang, Tzu-yung; Michel, Anna P. M.; Zanghi, Eric; Gmachl, Claire F.

2013-01-01

67

Wavelength-modulated differential laser photothermal radiometry for blood glucose measurements  

International Nuclear Information System (INIS)

A Wavelength-Modulated Differential Laser Photothermal Radiometer (WM-DPTR) technique was used for non-invasive blood glucose monitoring in the mid-IR range, where the prominent absorption peak is glucose specific and isolated from other interfering peaks in human blood. The WM-DPTR method consists of the out-of-phase modulated excitation at two discrete wavelengths 9.5 ?m and 10.4 ?m (near the peak and the baseline of glucose absorption), generated from two quantum cascade lasers (QCL) and the differential emission detection through a thermal-wave upconversion process via a HgCdZnTe (MCZT) detector (2-5 ?m). The differential method suppresses the background signal and reduces source-detection interference, thus enhancing glucose detection sensitivity. The results from aqueous glucose phantom (0-440 mg/dl) measurements demonstrate that both amplitude and phase of the WM-DPTR signal can be used for glucose detection. The dynamic range and the sensitivity of the glucose detection are influenced greatly by the laser intensity ratio and modulation frequency. The optimal intensity ratio for high sensitivity is ?1. Other laser intensity ratios increase dynamic range but reduce sensitivity. Sensitivity increases with frequency.

68

Wavelength-modulated differential laser photothermal radiometry for blood glucose measurements  

Energy Technology Data Exchange (ETDEWEB)

A Wavelength-Modulated Differential Laser Photothermal Radiometer (WM-DPTR) technique was used for non-invasive blood glucose monitoring in the mid-IR range, where the prominent absorption peak is glucose specific and isolated from other interfering peaks in human blood. The WM-DPTR method consists of the out-of-phase modulated excitation at two discrete wavelengths 9.5 {mu}m and 10.4 {mu}m (near the peak and the baseline of glucose absorption), generated from two quantum cascade lasers (QCL) and the differential emission detection through a thermal-wave upconversion process via a HgCdZnTe (MCZT) detector (2-5 {mu}m). The differential method suppresses the background signal and reduces source-detection interference, thus enhancing glucose detection sensitivity. The results from aqueous glucose phantom (0-440 mg/dl) measurements demonstrate that both amplitude and phase of the WM-DPTR signal can be used for glucose detection. The dynamic range and the sensitivity of the glucose detection are influenced greatly by the laser intensity ratio and modulation frequency. The optimal intensity ratio for high sensitivity is {approx}1. Other laser intensity ratios increase dynamic range but reduce sensitivity. Sensitivity increases with frequency.

Guo, X; Mandelis, A; Matvienko, A; Sivagurunathan, K [Department of MIE, University Toronto, 5 King' s College Road, Toronto, ON M5S 3G8 (Canada); Zinman, B, E-mail: guox@mie.utoronto.c [Samuel Luenfeld Research Institute, Mount Sinai Hospital, University of Toronto, 60 Murray Street, Toronto, ON M5T 3L9 (Canada)

2010-03-01

69

Precision magnetic measurements by the floating wire analog technique  

International Nuclear Information System (INIS)

Two SuperHILAC magnetic spectrometers were calibrated by means of current-carrying, floating wires. An effective radius-of-curvature as a function of single position measurements of magnetic-induction was determined with a probable error of +-0.02% over the range of rigidity: 0.3 less than or equal to B rho less than or equal to 2.4 (Tesla-meters). Employed in the calibrations were: optical detectors for determining wire position, an eddy-current jiggler for reducing pulley stiction, a vacuum re-entrant tube for allowing calibration under spectrometer operating conditions, two-axis gradient correction coils for operating an NMR magnetometer in gradients of 70 Gauss/cm, a calculator program for facilitating data collection, and a computer program for data reduction and presentation

70

Monte Carlo simulation of non-invasive glucose measurement based on FMCW LIDAR  

Science.gov (United States)

Continuous non-invasive glucose monitoring is a powerful tool for the treatment and management of diabetes. A glucose measurement method, with the potential advantage of miniaturizability with no moving parts, based on the frequency modulated continuous wave (FMCW) LIDAR technology is proposed and investigated. The system mainly consists of an integrated near-infrared tunable semiconductor laser and a detector, using heterodyne technology to convert the signal from time-domain to frequency-domain. To investigate the feasibility of the method, Monte Carlo simulations have been performed on tissue phantoms with optical parameters similar to those of human interstitial fluid. The simulation showed that the sensitivity of the FMCW LIDAR system to glucose concentration can reach 0.2mM. Our analysis suggests that the FMCW LIDAR technique has good potential for noninvasive blood glucose monitoring.

Xiong, Bing; Wei, Wenxiong; Liu, Nan; He, Jian-Jun

2010-11-01

71

Noninvasive optical polarimetric glucose sensing using a true phase measurement technique.  

Science.gov (United States)

The focus of this paper was to describe the development and testing of a noninvasive true phase optical polarimetry sensing system to monitor in vivo glucose concentrations. To demonstrate the applicability of this optical sensor for glucose measurement, we first calibrated the system and then tested it in vitro using both a glass test cell filled with glucose solution in the physiologic range, with a path length of 0.9 cm to approximate one centimeter path length present in the anterior chamber of the eye, and then on an excised human eye. Our technique used helium neon laser light which was coupled through a rotating linear polarizer along with two stationary linear polarizers and two detectors to produce reference and signal outputs whose amplitudes varied sinusoidally with a frequency of twice the angular velocity of the rotating polarizer, and whose phase was proportional to the rotation of the linear polarization vector passing through the glucose solution. PMID:1516942

Coté, G L; Fox, M D; Northrop, R B

1992-07-01

72

A novel function for a glucose analog of blood group H antigen as a mediator of leukocyte-endothelial adhesion via intracellular adhesion molecule 1.  

Science.gov (United States)

The 4A11 antigen is a unique cytokine-inducible antigen up-regulated on rheumatoid arthritis synovial endothelium compared with normal endothelium. In soluble form, this antigen, Lewisy-6/H-5-2 (Ley/H), or its glucose analog, 2-fucosyllactose (H-2g), mediates angiogenesis. The Ley/H antigen is structurally related to the soluble E-selectin ligand, sialyl Lewisx, and is selectively expressed in skin, lymphoid organs, thymus, and synovium, suggesting that it may be important in leukocyte homing or adhesion. In the present study, we used H-2g as a functional substitute to demonstrate a novel property for Ley/H antigen in inducing leukocyte-endothelial adhesion. H-2g significantly enhanced the expression of human dermal microvascular endothelial cells (HMVECs) intercellular adhesion molecule-1 (ICAM-1), but not vascular cell adhesion molecule-1, E-selectin, and P-selectin. Immunoprecipitation and Western blotting showed glycolipids Ley-6, H-5-2, or the glucose analog H-2g quickly activated human microvascular endothelial cell line-1 (HMEC-1) Janus kinase 2 (JAK2) and that the JAK2 inhibitor, AG-490, completely inhibited HMVEC ICAM-1 expression and HL-60 adhesion to HMEC-1s. Use of a JAK/signal transducer and activator of transcription (STAT) profiling system confirmed that H-2g selectively activated STAT3 but not STAT1 and STAT2. AG-490 inhibited H-2g-induced Erk1/2 and PI3K-Akt activation, suggesting that JAK2 is upstream of the Erk1/2 and PI3K-Akt pathways. Furthermore, the JAK2 inhibitor AG-490, the Erk1/2 inhibitor PD98059, or the phosphatidylinositol 3-kinase inhibitor LY294002 or antisense oligodeoxynucleotides directed against JAK2, Erk1/2, or phosphatidylinositol 3-kinase blocked H-2g-induced HMVEC ICAM-1 expression and HL-60 adhesion to HMEC-1s. Hence, H-2g signals through JAK2 and its downstream signal transducers STAT3, Erk1/2, and phosphatidylinositol 3-kinase result in ICAM-1 expression and cell adhesion. Potential treatment strategies through the inhibition of JAK-dependent pathways to target H-2g signals may provide a useful approach in inflammation-driven diseases like rheumatoid arthritis. PMID:12672794

Zhu, Kui; Amin, M Asif; Kim, Michael J; Katschke, Kenneth J; Park, Christy C; Koch, Alisa E

2003-06-13

73

Fastbus system for analog signal and time interval measurement on the SFERA spectrometer  

International Nuclear Information System (INIS)

Measurement system for analog and time intervals for JINR SFERA spectrometer is developed on the basis of FASTBUS standard. Block-diagrams 16-channel eight digit analog-to digital converter and 16-channel time-to-digital converter are given. Minimal access time to FASTBUS segment constituted 60 mks within realized comminication flowsheets of FASTBUS and CAMAC buses. Absolute time for data transmission constituted 1-3 ms. System software is of two-level structure. The system is used for investigations into scintillation detectors and into time structure of JINR synchrotron beam

74

Simulation study of in vitro glucose measurement by NIR spectroscopy and a method of error reduction  

International Nuclear Information System (INIS)

The effects of some important factors on the blood glucose measurements by NIR spectroscopy are investigated by numerical simulation, and a method is proposed to significantly reduce the prediction errors induced by these effects. The changes in the absorbance spectra with the changes in the glucose concentration, temperature and scattering characteristics of background tissue are obtained by a Monte Carlo simulation of light propagation for the wavelength range from 1200 nm to 1800 nm. The glucose concentration is predicted by applying a multivariate analysis to the numerically simulated spectra. This process estimates the errors in the prediction of the glucose concentration induced by the temperature and scattering changes. It has been found that only 1 deg C change in the temperature or only 1% change in the scattering coefficient induces about 500 mg dl-1 or 300 mg dl-1 errors, respectively, in the prediction of the glucose concentration. These errors can be significantly reduced to less than 20 mg dl-1 of the glucose concentration by incorporating the effects of the temperature and scattering characteristics on the spectra to the multivariate analysis

75

The measurement of the nigrostriatal dopaminergic function and glucose metabolism in patients with movement disorders  

Energy Technology Data Exchange (ETDEWEB)

The nigrostriatal dopaminergic function and glucose metabolism were evaluated in 34 patients with various movement disorders by using positron emission tomography with [sup 18]F-Dopa and [sup 18]F-FDG respectively. The [sup 18]F-Dopa uptake in the striatum (the caudate head and the putamen) decreased in patients with Parkinson's disease but was relatively unaffected in the caudate. The cerebral glucose metabolism was normal in patients with Parkinson's disease. The [sup 18]F-Dopa uptake in the striatum also decreased in cases of atypical parkinsonism and in cases of progressive supranuclear palsy, but there was no difference in the uptake between the caudate and the putamen. The glucose metabolism decreased in the cerebral hemisphere including the striatum; this finding was also different from those of Parkinson's disease. A normal [sup 18]F-Dopa uptake in the striatum with a markedly decreased striatal glucose metabolism and a mildly decreased cortical glucose metabolism was observed in cases of Huntington's disease and Wilson's disease. The [sup 18]F-Dopa uptake in the striatum increased and the glucose metabolism was normal in cases of idiopathic dystonia. Various patterns of [sup 18]F-Dopa uptake and glucose metabolism were thus observed in the various movement disorders. These results suggest that the measurements of the [sup 18]F-Dopa uptake and the cerebral glucose metabolism would be useful for the evaluation of the striatal function in various movement disorders. (author).

Otsuka, Makoto; Ichiya, Yuichi; Kuwabara, Yasuo; Sasaki, Masayuki; Fukumura, Toshimitsu; Masuda, Kouji; Shima, Fumio; Kato, Motohiro (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

1992-12-01

76

A dielectric inverse problem applied to human skin measurements during glucose excursions.  

Science.gov (United States)

A fringing field capacitive sensor has been used to measure the dielectric properties of human skin and underlying tissue in the MHz frequency range. It has recently been shown in clinical experimental studies that these dielectric properties can be related to the effects of in vivo glucose variations of the test subject. Previously, the relationship between electrical impedance and the glucose level has been established via statistical methods, such as the regression method. In this work, we explored a different approach, namely the resolution of the so-called inverse problem. First we applied the method on an artificial two-layer lossy system in order to test the sensitivity of the solution to forced changes in the layer properties and its stability to a constant setting. After validation of this method on artificial systems, a similar inverse problem was set and solved for dielectric measurements on human skin during an induced glucose excursion, where the skin is also modelled as a double-layer system. The changes of the measured permittivity and conductivity of the second layer versus the glucose changes are calculated for 22 study days. The statistical distribution shows that the median slopes of both dielectric properties are negative. These results can be used to test our hypothesis and to continue building potential explanations for the phenomena induced by the glucose changes on the skin layer dielectric parameters. PMID:21743123

Dewarrat, F; Falco, L; Mueller, M; Reinhard, S; Caduff, A; Talary, M S

2011-08-01

77

Measurement of the Incretin Hormones: Glucagon-Like Peptide-1 and Glucose-Dependent Insulinotropic Peptide  

DEFF Research Database (Denmark)

The two incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), are secreted from the gastrointestinal tract in response to meals and contribute to the regulation of glucose homeostasis by increasing insulin secretion. Assessment of plasma concentrations of GLP-1 and GIP is often an important endpoint in both clinical and preclinical studies and, therefore, accurate measurement of these hormones is important. Here, we provide an overview of current approaches for the measurement of the incretin hormones, with particular focus on immunological methods.

Kuhre, Rune Ehrenreich; Wewer Albrechtsen, Nicolai Jacob

2015-01-01

78

Measurement of the incretin hormones : glucagon-like peptide-1 and glucose-dependent insulinotropic peptide  

DEFF Research Database (Denmark)

The two incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), are secreted from the gastrointestinal tract in response to meals and contribute to the regulation of glucose homeostasis by increasing insulin secretion. Assessment of plasma concentrations of GLP-1 and GIP is often an important endpoint in both clinical and preclinical studies and, therefore, accurate measurement of these hormones is important. Here, we provide an overview of current approaches for the measurement of the incretin hormones, with particular focus on immunological methods.

Kuhre, Rune Ehrenreich; Wewer Albrechtsen, Nicolai Jacob

2014-01-01

79

Noninvasive blood glucose measurement system based on three wavelengths in near-infrared region  

Science.gov (United States)

Near-infrared region of optical spectrum extends from 0.7 to 2.5?m and can be used for quantitative measurement of organic functional groups, especially C-H, O-H, N-H and C=O. Analyzing sample concentration by near infrared spectroscopy focuses on the design of the optical sensor and the spectral data processing. Noninvasive blood glucose measurement methods using near-infrared spectroscopy usually apply a beam of light to irradiate the blood region of human, and then extract the information of blood glucose from the spectrum. The key is to improve the signal to noise ratio so that very low glucose absorption can be detected. In this paper, according to the absorption of glucose, a noninvasive blood glucose measurement system based on three wavelengths in the near-infrared region was designed. The system included several important parts such as the light source, the optical chopper, the detector and the lock-in amplifier. The three wavelengths were respectively chosen at the signal wavelength 1610nm by glucose absorption peak in the overtone band and the reference wavelengths 1200/1350nm to eliminate the interference effect. The optical probe used an annular light bundle to greatly increase the intensity of incidence light and improve the signal-noise ratio. Two group experiments of glucose aqueous solutions with different concentration interval in the normal human physiological blood glucose range (0-500mg/dL) have been done to evaluate the predictive performance of the system. In these group experiments, the partial least square algorithm was used to predict the glucose concentration. The preliminary results showed when the interval was 100mg/dL, the correlation coefficient (R) was 0.998 and the root mean square error of prediction (RMSEP) was 17.08mg/dL; and when the interval was 20mg/dL, the values of R and RMSEP were 0.959 and 23.22mg/dL, respectively.

Chen, Yaqin; Bai, Ge; Xiao, Jun; Wang, Long; Luo, Qingming

2007-05-01

80

Classification of diabetes and measurement of blood glucose concentration noninvasively using near infrared spectroscopy  

Science.gov (United States)

Developing noninvasive blood glucose monitoring method is an to immense need to alleviate the pain and suffering of diabetics associated with the frequent pricking of skin for taking blood sample. A hybrid algorithm for multivariate calibration is proposed to improve the prediction performance of classification of diabetes and measurement of blood glucose concentration by near infrared (NIR) spectroscopy noninvasively. The algorithm is based on wavelet prism modified uninformative variable elimination approach (WP-mUVE) combined with least squares support vector machine (LSSVM), named as WP-mUVE-LSSVM. The method is successfully applied to diabetic classification experiment (in vivo) and blood glucose concentration measurement experiment (in vivo) respectively. Human tongue is selected as the measuring site in this study. To evaluate effectiveness of pretreatment method and quality of calibration models, several usually used pretreatment methods and kernel functions of LSSVM are introduced comparing with our method. Higher quality data is obtained by our pretreatment method owing to the elimination of varying background and noise of spectra data simultaneously. Better prediction accuracy and adaptability are obtained by LSSVM model with radial basis kernel function. The results indicate that WP-mUVE-LSSVM holds promise for the classification of diabetes and measurement of blood glucose concentration noninvasively based on human tongue using NIR spectroscopy.

Li, Zhe; Li, Gang; Yan, Wen-Juan; Lin, Ling

2014-11-01

81

Glucose transport carrier of human erythrocytes. Radiation target size measurement based on flux inactivation  

International Nuclear Information System (INIS)

Intact human erythrocytes frozen in the presence of cryoprotective reagents and irradiated with an electron beam retained their diffusion barrier to L-glucose. The carrier-mediated flux of D-glucose, on the other hand, was inactivated as a simple exponential function of the radiation dose. Classical target size analysis of this data yielded a molecular size of 185,000 daltons for the carrier. This represents the first measurement of the functional size of a transport protein based directly on flux inactivation

82

In vitro measurements of physiological glucose concentrations in biological fluids using mid-infrared light.  

Science.gov (United States)

Mid-infrared transmission spectroscopy using broadband mid-infrared or Quantum Cascade laser sources is used to predict glucose concentrations of aqueous and serum solutions containing physiologically relevant amounts of glucose (50-400 mg/dL). We employ partial least squares regression to generate a calibration model using a subset of the spectra taken and to predict concentrations from new spectra. Clinically accurate measurements with respect to a Clarke error grid were made for concentrations as low as 30 mg/dL, regardless of background solvent. These results are an important and encouraging step in the work towards developing a noninvasive in vivo glucose sensor in the mid-infrared. PMID:23847734

Liakat, Sabbir; Bors, Kevin A; Huang, Tzu-Yung; Michel, Anna P M; Zanghi, Eric; Gmachl, Claire F

2013-07-01

83

An investigation of the effect of in vivo interferences on Raman glucose measurements  

Science.gov (United States)

Raman spectroscopy is a promising technology for noninvasive blood glucose monitoring because of its good selectivity for the glucose molecule. The low sensitivity of the Raman signal however, makes it difficult to quantify the concentration of glucose directly from the Raman spectra. To solve this, statistical methods such as PCA (principle component analysis) and PLS (partial least square) are traditionally used. These statistical methods general work very well and give highly accurate results, provided there is no interference. In the in-vivo case however, there are many interferences such as the inhomogeneity of tissue, physiological changes, and denaturation of the tissue by the light source. This study investigates the affect of in-vivo interferences on Raman glucose measurements. In this study, a high throughput dispersive Raman system was constructed with an 830nm multimode laser, a multiple conductor optical fiber bundle, and a back-illuminated CCD spectrometer. A simply phantom was devised, which was comprised of a plastic cuvette fitted with a human fingernail window and glucose doped human serum used as the sample. To test the inhomogeneity of tissue samples, different sites of the phantom were exposed to the laser. In the case of denaturation, tests were conducted under two laser power densities: low (3.7mW/mm2) and high density (110mW/mm2). To simulate the physiological change, gelatin phantoms of varied concentration were investigated. The results of the study indicate that the dominant interferers for Raman in-vivo glucose measurements are the inhomogeneity of the tissue and the denaturation by the laser power density. The next phase for this study will be the design of a high SNR Raman system which affords a low power density laser sample illumination as well as larger volumetric illumination to mitigate the effects of tissue inhomogeneity.

Shim, Bongchu; Oh, Hyunho; Oh, Jeankun; Yang, Yongju; Ku, Yunhee; Kim, Moosub; Kim, Dami; Eum, Hyejin; Cho, Seongmoon; Miller, David R.

2011-03-01

84

The Balloon Analog Insurance Task (BAIT): A Behavioral Measure of Protective Risk Management  

OpenAIRE

Prior methods used to assess individual differences related to risk have not focused on an important component of risk management: how willing individuals are to pay for or take actions to insure what they already have. It is not clear whether this type of protective risk management taps into the same individual differences as does risk taking propensity measured by existing risk taking tasks. We developed a novel task to assess protective risk management, the Balloon Analog Insurance Task (B...

Essex, Brian G.; Lejuez, Carl W.; Qian, Rebecca Y.; Bernstein, Katherine; Zald, David H.

2011-01-01

85

[Ways to improve measurement accuracy of blood glucose sensing by mid-infrared spectroscopy].  

Science.gov (United States)

Mid-infrared (MIR) spectroscopy is applicable to blood glucose sensing without using any reagent, however, due to a result of inadequate accuracy, till now this method has not been used in clinical detection. The principle and key technologies of blood glucose sensing by MIR spectroscopy are presented in this paper. Along with our experimental results, the paper analyzes ways to enhance measurement accuracy and prediction accuracy by the following four methods: selection of optimized spectral region; application of spectra data processing method; elimination of the interference with other components in the blood, and promotion in system hardware. According to these four improving methods, we designed four experiments, i.e., strict determination of the region where glucose concentration changes most sensitively in MIR, application of genetic algorithm for wavelength selection, normalization of spectra for the purpose of enhancing measuring reproduction, and utilization of CO2 laser as light source. The results show that the measurement accuracy of blood glucose concentration is enhanced almost to a clinical detection level. PMID:16856417

Wang, Yan; Li, Ning; Xu, Kexin

2006-06-01

86

Maximum-likelihood reconstruction of photon returns from simultaneous analog and photon-counting lidar measurements  

CERN Document Server

We present a novel method for combining the analog and photon-counting measurements of lidar transient recorders into reconstructed photon returns. The method takes into account the statistical properties of the two measurement modes and estimates the most likely number of arriving photons and the most likely values of acquisition parameters describing the two measurement modes. It extends and improves the standard combining ("gluing") methods and does not rely on any ad hoc definitions of the overlap region nor on any ackground subtraction methods.

Veberic, Darko

2011-01-01

87

H-2g, a glucose analog of blood group H antigen, mediates monocyte recruitment in vitro and in vivo via IL-8/CXCL8  

Directory of Open Access Journals (Sweden)

Full Text Available Bradley J Rabquer,1,2 Yong Hou,1 Jeffrey H Ruth,1 Wei Luo,1 Daniel T Eitzman,1 Alisa E Koch,3,1 Mohammad A Amin11University of Michigan Medical School, Department of Internal Medicine, Ann Arbor, MI, USA; 2Albion College, Biology Department, Albion, MI, USA; 3VA Medical Service, Department of Veterans Affairs, Ann Arbor, MI, USAObjective: Monocyte (MN recruitment is an essential inflammatory component of many autoimmune diseases, including rheumatoid arthritis (RA. In this study we investigated the ability of 2-fucosyllactose (H-2g, a glucose analog of blood group H antigen to induce MN migration in vivo and determined if H-2g-induced interleukin-8 (IL-8/CXCL8 plays a role in MN ingress in RA.Methods: Sponge granuloma and intravital microscopy assays were performed to examine H-2g-induced in vivo MN migration and rolling, respectively. MNs were stimulated with H-2g, and the production of IL-8/CXCL8 was assessed by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. Lastly, in vitro MN migration assays and an in vivo RA synovial tissue severe combined immunodeficiency mouse model were used to determine the role of IL-8/CXCL8 in H-2g-induced MN migration.Results: In vivo, H-2g induced significantly greater MN migration compared to phosphate buffered saline. Intravital microscopy revealed that H-2g mediates MN migration in vivo by inducing MN rolling. In addition, H-2g induced MN production of IL-8/CXCL8, a process that was dependent on Src kinase. Moreover, we found that H-2g mediated MN migration in vitro, and in vivo migration was inhibited by a neutralizing anti-IL-8/CXCL8 antibody.Conclusion: These findings suggest that H-2g mediates MN recruitment in vitro and in vivo (in part via IL-8/CXCL8.Keywords: inflammation, rheumatoid arthritis, chemokine, migration

Rabquer BJ

2012-09-01

88

Development of portable health monitoring system for automatic self-blood glucose measurement  

Science.gov (United States)

In this study, a new HMS (Health Monitoring System) device is developed for diabetic patient. This device mainly consists of I) 3D blood vessel searching unit and II) automatic blood glucose measurement (ABGM) unit. This device has features such as 1)3D blood vessel location search 2) laptop type, 3) puncturing a blood vessel by using a minimally invasive micro-needle, 4) very little blood sampling (10?l), and 5) automatic blood extraction and blood glucose measurement. In this study, ABGM unit is described in detail. It employs a syringe type's blood extraction mechanism because of its high accuracy. And it consists of the syringe component and the driving component. The syringe component consists of a syringe itself, a piston, a magnet, a ratchet and a micro-needle whose inner diameter is about 80?m. And the syringe component is disposable. The driving component consists of body parts, a linear stepping motor, a glucose enzyme sensor and a slider for accurate positioning control. The driving component has the all-in-one mechanism with a glucose enzyme sensor for compact size and stable blood transfer. On designing, required thrust force to drive the slider is designed to be greater than the value of the blood extraction force. Further, only one linear stepping motor is employed for blood extraction and transportation processes. The experimental result showed more than 80% of volume ratio under the piston speed 2.4mm/s. Further, the blood glucose was measured successfully by using the prototype unit. Finally, the availability of our ABGM unit was confirmed.

Kim, Huijun; Mizuno, Yoshihumi; Nakamachi, Eiji; Morita, Yusuke

2010-02-01

89

Measurement of glucose utilization by Pseudomonas fluorescens that are free-living and that are attached to surfaces  

International Nuclear Information System (INIS)

The assimilation and respiration of glucose by attached and free-living Pseudomonas fluorescens were compared. The attachment surfaces were polyvinylidene fluoride, polyethylene, and glass. Specific uptake of [1C]glucose was determined after bacterial biomass was measured by (1) microscopic counts or (2) prelabelling of cells by providing [3H]leucine as substrate, followed by dual-labelling scintillation counting. The glucose concentration was 1.4, 3.5, 5.5, 7.6, or 9.7 ?M. Glucose assimilation by cells which became detached from the surfaces during incubation with glucose was also measured after the detached cells were collected by filtration. The composition of the substratum had no effect on the amount of glucose assimilated by attached cells. Glucose assimilation by attached cells exceeded that by free-living cells by a factor of between 2 and 5 or more, and respiration of glucose by surface-associated cells was greater than that by free-living bacteria. Glucose assimilation by detached cells was greater than that by attached bacteria. Measurements of biomass by microscopic counts gave more consistent results than those obtained with dual-labelling, but in general, results obtained by both methods were corroborative

90

Performance Measurement of a Multi-Level/Analog Ferroelectric Memory Device Design  

Science.gov (United States)

Increasing the memory density and utilizing the unique characteristics of ferroelectric devices is important in making ferroelectric memory devices more desirable to the consumer. This paper describes the characterization of a design that allows multiple levels to be stored in a ferroelectric based memory cell. It can be used to store multiple bits or analog values in a high speed nonvolatile memory. The design utilizes the hysteresis characteristic of ferroelectric transistors to store an analog value in the memory cell. The design also compensates for the decay of the polarization of the ferroelectric material over time. This is done by utilizing a pair of ferroelectric transistors to store the data. One transistor is used a reference to determinethe amount of decay that has occurred since the pair was programmed. The second transistor stores the analog value as a polarization value between zero and saturated. The design allows digital data to be stored as multiple bits in each memory cell. The number of bits per cell that can be stored will vary with the decay rate of the ferroelectric transistors and the repeatability of polarization between transistors. This paper presents measurements of an actual prototype memory cell. This prototype is not a complete implementation of a device, but instead, a prototype of the storage and retrieval portion of an actual device. The performance of this prototype is presented with the projected performance of the overall device. This memory design will be useful because it allows higher memory density, compensates for the environmental and ferroelectric aging processes, allows analog values to be directly stored in memory, compensates for the thermal and radiation environments associated with space operations, and relies only on existing technologies.

MacLeod, Todd C.; Phillips, Thomas A.; Ho, Fat D.

2007-01-01

91

Low power analog readout front-end electronics for time and energy measurements  

International Nuclear Information System (INIS)

We report on the design and measurements of an analog front-end readout electronics dedicated for silicon microstrip detectors with relatively large capacitance of the order of tens pF for time and energy measurements of incoming pulses. The front-end readout electronics is required to process input pulses with an average rate of 150 kHz/channel with low both power consumption and noise at the same time. In the presented solution the single channel is built of two different parallel processing paths: fast and slow. The fast path includes the fast CR–RC shaper with the peaking time tp=40 ns and is optimized to determine the input charge arrival time. The slow path, which consists of the slow CR–(RC)2 shaper with the peaking time tp=80 ns, is dedicated for low noise accurate energy measurement. The analog front-end electronics was implemented in UMC 180 nm CMOS technology as a prototype ASIC AFE. The AFE chip contains 8 channels with the size of 58 ?m×1150 ?m each. It has low power dissipation Pdiss=3.1 mW per single channel. The article presents the details of the front-end architecture and the measurement results

92

Development of an analog processing circuit for IR-radiation power and noncontact position measurements  

Science.gov (United States)

An analog circuit which simultaneously performs radiation power and position measurement of an IR-laser spot (wavelength 1.3?m) on a four quadrant photodiode is presented and described. Its main features are 2MHz-bandwidth and low noise (14mVrms) for a nominal working radiation power of 2mW. This circuit has been implemented for the detection stage of an internal IR-laser deflection set-up, used to measure internal temperature gradients and free carrier concentration in vertical power devices. The measurements of the previously mentioned magnitudes inside the drift region of a 600V PT-IGBT are presented under critical operation conditions. This circuit, however, can also be used in other noncontact position and power radiation detection systems that require a high bandwidth and low noise levels. Moreover, the different noise sources along the detecting system have been identified. It is shown that the main contribution to the noise level at the processing circuit output is basically introduced by its second stage (analog divisor), assuring, for a 1mm laser spot centered at the photodetector, a maximum resolution in position measurement below 2?m.

Perpiñà, Xavier; Jordà, Xavier; Vellvehi, Miquel; Millán, José; Mestres, Narcís

2005-02-01

93

Precision analog signal processor for beam position measurements in electron storage rings  

International Nuclear Information System (INIS)

Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y position entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM

94

Precision analog signal processor for beam position measurements in electron storage rings  

International Nuclear Information System (INIS)

Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y posit ion entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM

95

Low power analog readout front-end electronics for time and energy measurements  

Energy Technology Data Exchange (ETDEWEB)

We report on the design and measurements of an analog front-end readout electronics dedicated for silicon microstrip detectors with relatively large capacitance of the order of tens pF for time and energy measurements of incoming pulses. The front-end readout electronics is required to process input pulses with an average rate of 150 kHz/channel with low both power consumption and noise at the same time. In the presented solution the single channel is built of two different parallel processing paths: fast and slow. The fast path includes the fast CR–RC shaper with the peaking time t{sub p}=40 ns and is optimized to determine the input charge arrival time. The slow path, which consists of the slow CR–(RC){sup 2} shaper with the peaking time t{sub p}=80 ns, is dedicated for low noise accurate energy measurement. The analog front-end electronics was implemented in UMC 180 nm CMOS technology as a prototype ASIC AFE. The AFE chip contains 8 channels with the size of 58 ?m×1150 ?m each. It has low power dissipation P{sub diss}=3.1 mW per single channel. The article presents the details of the front-end architecture and the measurement results.

Kleczek, R., E-mail: rafal.kleczek@agh.edu.pl; Grybos, P.; Szczygiel, R.

2014-06-01

96

Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography  

International Nuclear Information System (INIS)

While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography (13N-ammonia) are promising, their utility and value remains to be determined in man. If this technique can be applied to patients with acute myocardial ischemia or infarction it may permit delineation of regional myocardial segments with altered, yet still active metabolism. Further, it may become possible to evaluate the effects of interventions designed to salvage reversibly injured myocardium by this technique

97

Reproducibility of cerebral glucose utilization measured by positron emission tomography and the [18F]-2-fluoro-2-deoxy-d-glucose method in resting, healthy human subjects  

International Nuclear Information System (INIS)

The stability of cerebral glucose utilization was examined in nine right-handed, healthy men (age, 24.88±2.93 years) using positron emission tomography (PET) and the [18F]-fluorodeoxyglucose (FDG) method. Each study was run twice at intervals of 1-12 weeks with the subject at rest. The average cerebral metabolic rate for glucose (CMRGlu) was 5.40±0.71 mg/100 g per min (coefficient of variance, 13.08). The average intraindividual variation of CMRGlu was 7.91%±15.46% (P=0.13). Metabolic indices (MI: Regional/mean cortical CMRGlu) were used to determine the regional cerebral metabolic distribution. The interindividual (coefficient of variance, 7.13) and intraindividual variabilities (average variation, -0.12%±8.76%) of MI were smaller than those of metabolic rates. No reproducible significant asymmetry was observed. The FDG method used with subjects at rest thus yields low intraindividual variability of both cerebral glucose consumption and regional metabolic distribution, even at an interval of several weeks. Cerebral glucose utilization measured under such conditions may act as a reliable reference for determination of the influences of physiological (activation), pharmacological or pathological processes on cerebral glucose metabolism. (orig.)

98

Measurements and quality assessments of near-infrared plasma glucose spectra in the combination band region using a scanning filter spectrometer  

OpenAIRE

Near-infrared measurements of glucose in human plasma are performed using a custom, rapid, high-throughput filter-based spectrometer covering a spectral range between 2080 and 2315 nm. Quality of the measured glucose signals is quantified through the use of two figures of merit: selectivity and limit of detection. Selectivity measures the uniqueness of the glucose spectrum from among the interfering spectra. Limit of detection measures the smallest glucose concentration change detectable. The...

Saptari, Vidi; Youcef-toumi, Kamal

2005-01-01

99

Evaluation of the Efficacy and Correlation between Blood Glucose Measured Using Glucometers and Enzymatic Laboratory Methods  

Directory of Open Access Journals (Sweden)

Full Text Available

Background and Objectives: Diabetes Mellitus (DM is the most common chronic metabolic disease, with many complications including renal failure, blindness and non-traumatic amputation, so it is important to monitor and regulate blood glucose. Considering how easy home blood glucose monitoring is, we decided to evaluate the performance of two available glucometers for detection of blood glucose compared with standard laboratory methods.

 

Methods: In this analytical study, we compared the capillary blood glucose levels of 60 volunteers with mean age of 32.8±9.6 years in Tabriz Mehr Laboratory as determined by test strips (two different Glucometers with venous blood glucose levels’ measurements by the enzymatic method (the standard laboratory kit. Data were analyzed using one way-ANOVA test, T-test, Pearson correlation and Bland and Altman plot.

 

Results: The mean differences of No: 1 and No: 2 Glucometers with enzymatic laboratory method were 20.78±11.61 and 4.5±3.76mg/dl respectively. The one way ANOVA test indicated significant differences between three methods (p<0.05. Further Duncan's test revealed significant differences between two devices (p=0.001 and device No.1 and laboratory method (p=0.001; however, the differences between device No.2 and laboratory method were not statistically significant (p=0.83.

 

Conclusion: According to the results, calibrating the devices with laboratory instruments in order to make major clinical decisions is recommended.

R Rasouli

2012-05-01

100

The characteristic time of glucose diffusion measured for muscle tissue at optical clearing  

International Nuclear Information System (INIS)

The study of agent diffusion in biological tissues is very important to understand and characterize the optical clearing effects and mechanisms involved: tissue dehydration and refractive index matching. From measurements made to study the optical clearing, it is obvious that light scattering is reduced and that the optical properties of the tissue are controlled in the process. On the other hand, optical measurements do not allow direct determination of the diffusion properties of the agent in the tissue and some calculations are necessary to estimate those properties. This fact is imposed by the occurrence of two fluxes at optical clearing: water typically directed out of and agent directed into the tissue. When the water content in the immersion solution is approximately the same as the free water content of the tissue, a balance is established for water and the agent flux dominates. To prove this concept experimentally, we have measured the collimated transmittance of skeletal muscle samples under treatment with aqueous solutions containing different concentrations of glucose. After estimating the mean diffusion time values for each of the treatments we have represented those values as a function of glucose concentration in solution. Such a representation presents a maximum diffusion time for a water content in solution equal to the tissue free water content. Such a maximum represents the real diffusion time of glucose in the muscle and with this value we could calculate the corresponding diffusion coefficient. (paper)

101

Harmonical oscillator and electro-mechanical analogy: an interdiscinary experiment to high precision mass variation measurements  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese De forma geral, os cursos de física clássica oferecidos nas universidades carecem de exemplos de aplicações nas áreas de química e biologia, o que por vezes desmotivam os alunos de graduação destas áreas a estudarem os conceitos físicos desenvolvidos em sala de aula. Neste texto, a analogia entre os [...] osciladores elétrico e mecânico é explorada visando possívies aplicações em química e biologia, mostrando-se de grande valia devido ao seu uso em técnicas de medição de variação de massa com alta precisão, tanto de forma direta como indireta. Estas técnicas são conhecidas como técnicas eletrogravimétricas e são de especial importância em aplicações que envolvem biossensores. Desta forma, o texto explora o estudo da analogia eletromecânica de forma interdisciplinar envolvendo as áreas de física, química e biologia. Baseado nessa analogia é proposto um experimento que permite a sua aplicação em diferentes níveis conceituais dessas disciplinas, tanto em abordagem básica como mais profunda. Abstract in english In general, the traditional Physics courses needs examples of the aplications of the Physics concepts in other areas such as Chemistry and Biology. This lacks tend to demotivate Chemistry and Biology students regarding to deal with Physical concepts developed in classroom. In this work, the analogy [...] among mechanic and electric oscillators is investigated to be applied in Chemistry and Biology areas, showing to be valuable due to its aplication in techniques that aims to measure mass variation with high precision. This measure could be made in a direct or indirect way. These techniques are known as electrogravimetric techniques and they are important in biosensor aplications. Thus, this paper explores the electromechanic analogy in an interdisciplinary way involving areas like Physics, Chemistry and Biology. Based on this analogy, it is proposed an experiment that can be applied in different ways, i.e. by an basic approach or more deeper, depending on the students specific formation, in other words, Physics, Chemistry or Biology.

Ailton M., Watanabe; Adriano dos, Santos; Paulo R., Bueno.

102

Measurement of glucose concentration in a thin turbid medium by a transmitted Gaussian beam  

Science.gov (United States)

We show that it is possible to measure glucose concentration in a thin sample containing a turbid medium that simulates optical properties of biological tissue by recording the profile of a sinusoidal reflective grating by means of a laser Gaussian beam. We have described a similar approach for the case of transparent samples in a previous report. Although due to the turbidity of the sample the laser beam is scattered, we show that the probe beam is still sensitive enough to allow the detection of the grating profile. We describe how the changes recorded by the system, when profiling a region of the grating, allow us to determine the concentration of glucose in the turbid medium. We include experimental results.

Cervantes-L, Joel; Cywiak, Moisés; Olvera-R, Octavio; Cywiak, David

2014-11-01

103

Relation of measured brain glucose utilisation and cerebral atrophy in man.  

OpenAIRE

The effect of cerebral atrophy on measured cerebral metabolic rates for glucose (CMRglc), as determined with positron emission tomography (PET), was examined in 49 healthy males aged 21-83 years. Global CMRglc and regional CMRglc for 34 grey matter regions parallel to and from 30 to 80 mm above the inferior orbital meatal (IOM) line were measured under resting conditions, using [18F]-fluorodeoxyglucose and an ECAT II positron emission tomograph. Using a GE 8800 CT/T scanner, slices parallel t...

Schlageter, N. L.; Horwitz, B.; Creasey, H.; Carson, R.; Duara, R.; Berg, G. W.; Rapoport, S. I.

1987-01-01

104

Gonadotropin release in periovulatory heifers after GnRH analogs measured by two types of immunoassays.  

Science.gov (United States)

This study on heifers (n = 27) compared the effects of a GnRH antagonist (Antarelix) and those of an agonist (Triptorelin) on gonadotropin release during the periovulatory period of the oestrous cycle. In three experiments (EXP I-III), an initial injection of GnRH analogs was given 48 h after a single PGF 2alpha pretreatment during the luteal phase, with a further five at 12 h intervals. A challenge by a GnRH agonist (Gonavet) was performed six hours after the last application of analogs. In EXP I (n = 9), heifers received six times 1.5 mg of Antarelix, 0.5 mg of Triptorelin, and mannitol (5%; control), respectively. In EXP II (n = 12), identical Antarelix and Triptorelin treatments were followed by a single injection of estradiol-17beta valerate (6 h after Gonavet). The dosage of Antarelix was increased to 5 mg for each injection in EXP III (n = 6). Measurement of LH in blood plasma frequently sampled was performed parallely by a competitive RIA method (EXP I + II) and by a sandwich-type electro-chemiluminescence-immunoassay (ECLIA) in EXP III. This non-isotopic technique was also used to additionally analyse FSH levels. Results of EXP I showed that the GnRH antagonist equally suppressed LH surges and ovulation. On the contrary, prior to suppression of LH levels due to down-regulation of pituitary GnRH receptors the agonist Triptorelin induced an initial increase in LH concentration which was followed by ovulation. In the control animals we observed endogenous LH surges as well as smaller elevations after the agonist (Gonavet) challenge. An increase was also observed in antagonist, but not in Triptorelin treated heifers. Pituitary GnRH receptors were not detectable in animals previously treated by the analogs, whereas concentrations between 2.2-21.0 fmol/mg protein were measured in controls. Results of EXP II confirmed the described effects of GnRH analogs. Additionally, it was shown that exogenous estradiol is able to release LH from the pituitary, although a previous treatment by a GnRH agonist had dropped the pulsatile gonadotropin secretion. Contrary to the LH pattern and despite elevated amounts of the antagonist, the mean concentration and pulse number of FSH were not influenced by the antagonist treatment (EXP III). These data confirmed that (a) the reversibly blocked pituitary function induced by a potent GnRH antagonist may be a useful tool to study gonadotropin-dependent final follicular growth as well as ovulation in cyclic heifers and (b) the novel non-isotopic ECLIA methods for the determination of FSH and LH provided practical alternatives to other immunoassay types. PMID:12148088

Schneider, F; Bellmann, A; Becker, F; Bambang Poernomo, S; Rehfeldt, C; Nürnberg, G; Kanitz, W

2002-08-01

105

Clinical review: Consensus recommendations on measurement of blood glucose and reporting glycemic control in critically ill adults.  

OpenAIRE

The management reporting and assessment of glycemic control lacks standardization. The use of different methods to measure the blood glucose concentration and to report the performance of insulin treatment yields major disparities and complicates the interpretation and comparison of clinical trials. We convened a meeting of 16 experts plus invited observers from industry to discuss and where possible reach consensus on the most appropriate methods to measure and monitor blood glucose in criti...

Finfer, Simon; Wernerman, Jan; Preiser, Jean-charles; Cass, Tony; Desaive, Thomas; Hovorka, Roman; Joseph, Jeffrey I.; Kosiborod, Mikhail; Krinsley, James; Mackenzie, Iain; Mesotten, Dieter; Schultz, Marcus J.; Scott, Mitchell G.; Slingerland, Robbert; Den Berghe, Greet

2013-01-01

106

Simultaneous measurement of blood flow and glucose metabolism by autoradiographic techniques  

International Nuclear Information System (INIS)

A double tracer autoradiographic technique using 131I-iodo-antipyrine and 14C-deoxyglucose is presented for the simultaneous measurement of blood flow and cerebral glucose utilization in the same animal. 131I is a gamma emitting isotope with a half life of 8.06 days and can be detected with adequate resolution on standard autoradiographic films. Autoradiograms are made before and after decay of 131I; the time interval between the 2 exposures and the concentration of the 2 tracers is adjusted to avoid significant cross-contamination. In this way, 2 film exposures are obtained which can be processed quantitatively like single tracer autoradiograms. The validity of the method for the investigation of local coupling of flow and metabolism was tested under various physiological and pathophysiological conditions. Coupling was tight in barbiturate-anesthetized healthy animals, but not under halothane anesthesia where uncoupling occurred in various subcortical structures. Focal seizures induced by topical application of penicillin on the cortical surface led to a coupled increase of metabolism and flow in thalamic relay nuclei but not at the site of penicillin administration where increased glucose utilization was not accompanied by similar increase in blood flow. Both coupled and uncoupled increases in local glucose utilization were observed in spreading depression and in circumscribed areas of experimental brain tumors. The results obtained demonstrate that double tracer auobtained demonstrate that double tracer autoradiography allows allows the very precise local assessment of cerebral blood flow and glucose utilization, and, therefore, is particularly suited to the study of regional coupling processes under various experimental conditions

107

Slope characterization in combining analog and photon count data from atmospheric lidar measurements.  

Science.gov (United States)

A transient digitizer (Licel) connecting to a photomultiplier tube (PMT) can obtain lidar backscatter profiles in both photon count and analog signal. A lidar can detect higher atmospheric regions by combining (gluing) simultaneous analog and photon count data via the slope coefficient. In this work, the output of a PMT has been measured with a transient digitizer based on an intensity-stable light source. The slope value and dynamic range of the lidar profile have been characterized. The slope value is determined only by the gain of the PMT as it works in a linear range with a fixed pulse height discrimination threshold. The dynamic range of a glued lidar profile is settled by the slope value. The fitted slope has a more exact value when the selection criterion is given in terms of the independent variable for fitting. For practical lidar data, the fitted slope is more stable and reliable when the lower limit of the data range for fitting rises. PMID:25402893

Zhang, Yunpeng; Yi, Fan; Kong, Wei; Yi, Yang

2014-11-01

108

Non-Invasive Glucose Measurement by Use of Metabolic Heat Conformation Method  

Directory of Open Access Journals (Sweden)

Full Text Available A non-invasive glucose measurement system based on the method of metabolic heat conformation (MHC is presented in this paper. This system consists of three temperature sensors, two humidity sensors, an infrared sensor and an optical measurement device. The glucose level can be deduced from the quantity of heat dissipation, blood flow rate of local tissue and degree of blood oxygen saturation. The methodology of the data process and the measurement error are also analyzed. The system is applied in a primary clinical test. Compared with the results of a commercial automated chemistry analyzer, the correlation coefficient of the collected data from the system is 0.856. Result shows that the correlation coefficient improves when the factor of heat dissipated by evaporation of the skin is added in. A non-invasive method of measuring the blood flow rate of local tissue by heat transmission between skin and contacted conductor is also introduced. Theoretical derivation and numerical simulation are completed as well. The so-called normalized difference mean (NDM is chosen to express the quantity of the blood flow rate. The correlation coefficient between the blood flow rates by this method and the results of a Doppler blood flow meter is equal to 0.914.

Junfeng Li

2008-05-01

109

Analog method for measurement of longitudinal coupling impedance between electron ring and chamber  

International Nuclear Information System (INIS)

A measurement method is suggested of a longitudinal impedance, in which an analog of an electron ring is a metal ring. In this system standing waves are excited so that the wave number for one turn is a whole number. This is necessary to save the similarity of the system. From the difference of wave velocity along metal ring in adgezator chamber and wave velocity of line, is possible to define the imaginary component of this impedance. The wave velocity in adgezator is given from the ring resonance frequency which is measured with the aid of RF analyzer and frequency measurer. The wave velocity in ideal line is obtained through calculation. Real part of impedance is received from quality factor measurement of the circuit. Coupling between generator and ring, and analyzer and ring is weak. It does not effect the eigenfrequencies of the ring. The measuring results of imaginary part of the longitudinal impedance ring-chamber are compared with that from theoretical calculation for infinite walls. A good agreement of results has been obtained

110

Analog and time digitizer for two-dimensional data acquisition for time-of-flight measurements  

Energy Technology Data Exchange (ETDEWEB)

A CAMAC module has been developed to record simultaneously the pulse height and the elapsed time of an event following a start signal. The module is based on an 8-bit (256-channel) 100 MHz fast analog to digital converter (FADC) and a 16-bit (65536-channel) time digitizer with a maximum time range of 4.9 ms and a minimum resolving time of 20 ns. A short dead time in the data acquisition equipment is required to keep count loss corrections to an acceptable level at high count rates. The processing of the signal including storage of the data in 256-word buffer takes place during the 10 ns dead time of the module. A built-in digital to analog converter (DAC) can be used to set up and test the module. The unit can be used in several different ways, for example 1. as a multiparameter neutron time-of-flight spectrometer, 2. as a transient wave recorder with a continuous read-in, 3. as a transient wave recorder with a 16-block read-in and 4. as a self-triggering digital discriminator. In this report a description is given of the use of the system in neutron transmission measurements using the pulsed neutron source HELIOS at Harwell. In these measurements the count rates were several times the highest count rate previously recorded on such experiments at Harwell. The count loss and background were more easily and more accurately calculated from the information gained from the two-dimensional recording of the data.

Schmiedmayer, J.; Pernicka, M.; Moxon, M.C.

1989-03-15

111

Regional cerebral glucose consumption measured by positron emission tomography in patients with Wilson's disease  

International Nuclear Information System (INIS)

Using positron emission tomography (PET), the regional cerebral metabolic rate of glucose consumption (rCMRGlc) was measured in 14 patients with Wilson's disease (WD) and 23 normal subjects. In WD patients, cerebellar, striatal and - to a lesser extent - cortical and thalamic rCMRGlc were significantly decreased compared with controls. Striatal rCMRGlc was significantly reduced in those 4 patients who had recently started decoppering therapy as compared with striatal rCMRGlc measured in those 10 patients with longer duration of medication. Caudate rCMRGlc correlated significantly with various signs of extrapyramidal dysfunction. Cerebellar, thalamic and cortical rCMRGlc correlated significantly with the severity of pyramidal signs. These data indicate that the PET measurement of rCMRGlc may be a useful tool to evaluate cerebral involvement in WD and to monitor the response to treatment. (orig.)

112

[18F]-2-fluoro-2-deoxyglucose transport kinetics as a function of extracellular glucose concentration in malignant glioma, fibroblast and macrophage cells in vitro  

International Nuclear Information System (INIS)

FDG-PET is used to measure the metabolic rate of glucose. Transport and phosphorylation determine the amount of hexose analog that is phosphorylated and trapped. Competition occurs for both events, such that extracellular glucose concentration affects the FDG image. This study investigated the effect of glucose concentration on the rate of FDG accumulation in three cell lines. The results show that extracellular glucose concentration has a greater impact on the rate of FDG accumulation than the relative abundance of GLUT transporter subtypes

113

IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS  

International Nuclear Information System (INIS)

The organic haze produced from complex CH4/N2 chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH4 concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

114

IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS  

Energy Technology Data Exchange (ETDEWEB)

The organic haze produced from complex CH{sub 4}/N{sub 2} chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH{sub 4} concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

Hoerst, S. M.; Tolbert, M. A, E-mail: sarah.horst@colorado.edu [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO (United States)

2013-06-10

115

A New System Noise Measurement Method Using a 2-bit Analog-To-Digital Converter  

CERN Document Server

We propose a new method to measure the system noise temperature, $T_{\\rm sys}$, using a 2-bit analog-to-digital converter (ADC). The statistics of the digitized signal in a four-level quantization brings us information about the bias voltage and the variance, which reflects the power of the input signal. Comparison of the variances in {\\it hot} and {\\it sky} circumstances yields $T_{\\rm sys}$ without a power meter. We performed test experiments using the Kagoshima 6-m radio telescope and a 2-bit ADC to verify this method. Linearity in the power-variance relation was better than 99% within the dynamic range of 10 dB. Digitally measured $T_{\\rm sys}$ coincided with that of conventional measurement with a power meter in 1.8-% difference or less for elevations of $10^{\\circ} - 88^{\\circ}$. No significant impact was found by the bias voltages within the range between -3.7 and +12.8% with respect to the threshold voltage. The proposed method is available for existing interferometers that have a multi-level ADC, and...

Nakatake, Aki; Takeda, Koji

2010-01-01

116

A New System Noise Measuring Method Using a 2-Bit Analog-to-Digital Converter  

Science.gov (United States)

We propose a new measuring method for the system noise temperature, Tsys, using a 2-bit analog-to-digital converter (ADC). Statistics of the digitized signal in a four-level quantization gives us information about the bias voltage and the variance, which reflects the power of the input signal. A comparison of the variances in hot and sky circumstances yields Tsys without a power meter. We performed experimental tests using the Kagoshima 6 m radio telescope and a 2-bit ADC. The linearity in the power-variance relation was better than 99% within the dynamic range of 10 dB. Digitally measured Tsys was in agreement with that of a conventional measurement with a power meter, although the temperatures differed by 1.8%, or less, for elevations of 10°-88°. No significant impact was found by the bias voltages within a range of -3.7% to +12.8% with respect to the threshold voltage. The proposed method is available for existing interferometers that have a multilevel ADC, and release us from troubles caused by power meters.

Nakatake, Aki; Kameno, Seiji; Takeda, Koji

2010-10-01

117

NIR measurements of glucose in synthetic biological solutions using high-throughput angle-tuned filter spectrometer  

Science.gov (United States)

A noninvasive blood glucose monitoring device will provide an invaluable tool in the diagnosis and treatment of diabetes. Near infrared (NIR) absorption spectroscopy is one of the most promising optical techniques for in vivo blood glucose sensing to date. Successful realization of such a technology hinges on solving two main problems. First, instrument sensitivity needs to be improved in order to resolve the weak NIR spectral variations due to glucose physiological changes in the blood. Second, interfering signals due to other blood components and tissue changes need to be sufficiently eliminated or compensated for. A simple, low-cost, high-throughput, filter spectrometer optimized for long-wave NIR measurements of biological fluids is developed. The instrument provides noise spectra with a typical rms value of 7 ?AU between 2180 nm and 2310 nm with only 5 seconds of data measurement or averaging. Using such an instrument, spectra of aquaeous, synthetic biological solutions containing varying levels of glucose, BSA, triacetin, lactate and urea are obtained. Glucose spectra are isolated, despite the overlapping spectra. Glucose concentrations are predicted with excellent accuracy (SEP<=8.2 mg/dL) using the simple classical least-squares (CLS) and the connonly used partial least-squares (PLS) multivariate techniques.

Saptari, Vidi A.; Youcef-Toumi, Kamal; Zhang, John

2004-06-01

118

A Novel Analog Integrated Circuit Design Course Covering Design, Layout, and Resulting Chip Measurement  

Science.gov (United States)

This work describes a novel, first-year graduate-level analog integrated circuit (IC) design course. The course teaches students analog circuit design; an external manufacturer then produces their designs in three different silicon chips. The students, working in pairs, then test these chips to verify their success. All work is completed within…

Lin, Wei-Liang; Cheng, Wang-Chuan; Wu, Chen-Hao; Wu, Hai-Ming; Wu, Chang-Yu; Ho, Kuan-Hsuan; Chan, Chueh-An

2010-01-01

119

Are Tubes Containing Sodium Fluoride Still Needed for the Measurement of Blood Glucose in Hospital Laboratory Practice?  

Directory of Open Access Journals (Sweden)

Full Text Available Objectives: To compare glucose values obtained using sodium flouride (NaF tubes and serum separation tubes (SST in a tertiary care hospital laboratory setting.? Methods: This study was conducted at the Clinical Biochemistry Laboratory, Royal Hospital, Oman. During the study period (1 September–30 November 2013, 50 pairs (one NaF tube and one SST of patient’s blood specimens were randomly collected. Following separation of plasma (NaF tubes and serum (SST, glucose concentrations were measured by hexokinase assay using the Architect c8000. Fifteen pairs of these tubes were kept in the refrigerator at 4°C and plasma/serum glucose concentrations were measured daily up to seven days after collection.? Results: Comparing plasma (NaF and serum (SST results of glucose values (n=50 showed an average difference of 0.00mmol/L (range -0.60 to +0.60mmol/L. Bland Altman analysis gave a non-significant constant bias of 0.10 ±0.195mmol/L (bias ±SD. Pearson correlation between plasma (NaF and serum (SST glucose concentrations revealed a significant correlation approaching unity with r2= 0.9991. No significant differences in glucose values were noted for both plasma and serum in 15 pairs of NaF and SST tubes when analyzed seven days following refrigeration. Hemolysis was observed in five (10% NaF tubes compared with two (4% SST.? Conclusion: There is no difference in glucose values collected from plasma NaF tubes or serum SST, and so SST can be used in hospital laboratory settings as there are practical advantages, including cost-effectiveness and reduction in blood volume drawn when utilizing these tubes for glucose and other tests from a single blood collection tube.

Amira Al-Kharusi

2014-11-01

120

Analog earthquakes  

Energy Technology Data Exchange (ETDEWEB)

Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

Hofmann, R.B. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

1995-09-01

121

Analog earthquakes  

International Nuclear Information System (INIS)

Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository

122

[The net analyte preprocessing combined with radial basis partial least squares regression applied in noninvasive measurement of blood glucose].  

Science.gov (United States)

In order to improve the prediction accuracy of quantitative analysis model in the near-infrared spectroscopy of blood glucose, this paper, by combining net analyte preprocessing (NAP) algorithm and radial basis functions partial least squares (RBFPLS) regression, builds a nonlinear model building method which is suitable for glucose measurement of human, named as NAP-RBFPLS. First, NAP is used to pre-process the near-infrared spectroscopy of blood glucose, in order to effectively extract the information which only relates to glucose signal from the original near-infrared spectra, so that it could effectively weaken the occasional correlation problems of the glucose changes and the interference factors which are caused by the absorption of water, albumin, hemoglobin, fat and other components of the blood in human body, the change of temperature of human body, the drift of measuring instruments, the changes of measuring environment, and the changes of measuring conditions; and then a nonlinear quantitative analysis model is built with the near-infrared spectroscopy data after NAP, in order to solve the nonlinear relationship between glucose concentrations and near-infrared spectroscopy which is caused by body strong scattering. In this paper, the new method is compared with other three quantitative analysis models building on partial least squares (PLS), net analyte preprocessing partial least squares (NAP-PLS) and RBFPLS respectively. At last, the experimental results show that the nonlinear calibration model, developed by combining NAP algorithm and RBFPLS regression, which was put forward in this paper, greatly improves the prediction accuracy of prediction sets, and what has been proved in this paper is that the nonlinear model building method will produce practical applications for the research of non-invasive detection techniques on human glucose concentrations. PMID:24822427

Li, Qing-Bo; Huang, Zheng-Wei

2014-02-01

123

Measurements of CO2 Carbon Stable Isotopes at Artificial and Natural Analog Sites  

Science.gov (United States)

Carbon storage in geologic formations is one method to prevent carbon dioxide (CO2), produced by fossil fuel combustion, from entering the Earth's atmosphere. The monitoring, verification and accounting (MVA) of geologically sequestered CO2 is critical to the operation of a geologic storage site. Surface MVA techniques need to identify seepage from the sequestration reservoir at or below ambient CO2 concentrations. The CO2 carbon stable isotope ratio of is a sensitive diagnostic signature that can distinguish between anthropogenic and natural sources of CO2. Frequency Modulated spectroscopy (FMS) is an ultra-sensitive version of absorption spectroscopy that is capable of detecting the CO2 carbon stable isotope ratios. The technique involves phase modulation of the laser such that two side bands, spaced wider than the absorption feature of interest (in this case +/-2 GHz) are created. The signal is mixed with the local oscillator yielding a signal proportional to the species concentration. This FMS signature is recorded at multiple wavelengths to obtain the CO2 carbon isotope ratio.Two instruments using the FMS technique have been built and tested at LANL. One instrument draws ambient air into a multi-pass cell for a measurement, point source measurements. The other instrument uses an open-air path, tested up to 160 m (round trip), to measure the CO2 carbon isotopic ratio along the beam path, column average measurements. In this paper, results from multiple field deployments of one or both of the instruments will be presented. The Zero Emissions Research & Technology (ZERT) group at Montana State University established a field test site where controlled amounts of CO2 are released to test the performance of CO2 detection instruments and measurement techniques. The field site allows a controlled flow rate of CO2 to be released into the near surface through a 100 m long horizontal pipe. In July of 2009, a release was conducted, with a uniform flow rate of 0.2 tons per day, as the subsequent seepage was measured. There was a similar release, but at a flow rate of 0.15 tons/day, in July 2010. Stable isotope measurements have also been made at several natural analog sites. Two places of interest are the Valles Caldera National Preserve in NM and Soda Springs, ID. The Valle traps CO2 at night and can have very large swings in concentrations that test the instrument range. Soda Springs, ID has many carbonated natural springs and carbon isotope information from this site can provide information regarding CO2 from the deep subsurface, useful for future MVA work.

Humphries, S. D.; Clegg, S. M.; Rahn, T.; Fessenden, J. E.; Dobeck, L.; Spangler, L.; McLing, T. L.

2010-12-01

124

Isobaric analog states of neutron-rich nuclei. Doppler shift as a measurement tool for resonance excitation functions  

International Nuclear Information System (INIS)

We present a new approach for the measurement of resonance excitation functions of neutron-rich nuclei using Doppler shift information. Preliminary data from the first application of the method is presented in the spectroscopy studies of 7He isobaric analog states in 7Li. (orig.)

125

PING Gamma Ray and Neutron Measurements of a Meter-Sized Carbonaceous Asteroid Analog  

Science.gov (United States)

Determining the elemental composition of carbonaceous (spectral type C) asteroids is still one of the basic problems when studying these objects. The only main source of elemental composition information for asteroids is from their optical, NIR and IR properties, which include their spectral reflectance characteristics, albedo, polarization, and the comparison of optical spectroscopy with meteorite groups corresponding to asteroids of every spectral type. Unfortunately, these sources reflect observations from widely contrasting spatial scales that presently yield a void in the continuum of microscopic and macroscopic evidence, a lack of in situ measurement confirmation, and require deeper sensing techniques to discern the nature of these asteroids. The Probing In situ with Neutrons and Gamma rays (PING) instrument is ideally suited to address this problem because it can be used to determine the bulk elemental composition, H and C content, the average atomic weight and density of the surface and subsurface layers of C-type asteroids, and can provide measurements used to determine the difference between and distinguish between different types of asteroids. We are currently developing the PING instrument that combines gamma ray and neutron detectors with a 14 Me V pulsed neutron generator to determine the in-situ bulk elemental abundances and geochemistry of C-type asteroids with a spatial resolution of 1 m down to depths of tens of cm to 1 m. One aspect of the current work includes experimentally testing and optimizing PING on a known meter-sized Columbia River basalt C-type asteroid analog sample that has a similar composition and the same neutron response as that of a C-type asteroid. An important part of this effort focuses on utilizing timing measurements to isolate gamma rays produced by neutron inelastic scattering, neutron capture and delayed activation processes. Separating the gamma ray spectra by nuclear processes results in higher precision and sensitivity elemental composition measurements. Using gated data acquisition techniques allows for the unambiguous identification of gamma ray lines from different isotopes and nuclear processes, especially in situations when limited detector resolution results in overlapping gamma ray lines that cannot be individually resolved. In this paper, we will present the PING basalt layering experimental data, taken at the test facility at NASA Goddard Space Flight Center using the time tagged event-by-event data analysis technique, compared to our MCNPX computer simulation results for the C-type asteroid and basalt layering simulant models. Comparison of these data will show the advantages, validity, and measurement sensitivity of PING's nuclear interrogation methods to obtain more precise and sensitive in situ bulk elemental composition and density measurements of the subsurface of asteroids.

Bodnarik, J.; Burger, D.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Parsons, A.; Schweitzer, J.; Starr, R.; Trombka, J.

2011-01-01

126

Labelled antibody assays for measuring free triiodothyronine: evaluation and comparison with a labelled analog method  

International Nuclear Information System (INIS)

We evaluated analytically and clinically two new one-step labelled antibody assays for measuring free triiodothyronine (FT3): the first, radiolabelled with 125 I, Amerlex-MAB (MAB) from Kodak diagnostic, and the second, labelled with peroxidase, Enzymum-test FT3 (BM) from Boehringer Mannheim adapted for the Boehringer ES 600 analyzer. The clinical results were compared with those obtained with a radiolabelled analog tracer kit, Amerlex-M (M) from Kodak diagnostic. The latter kit is known to give low FT3 results in sera with low albumin concentrations. Analytical performances of the automated method (BM) were better than those obtained with the manual method (MAB): intra-assay reproducibility (CV<3% vs CV about 5%), inter-assay reproducibility (CV<4% vs CV between 4 and 8%) and mean drift (+1.25% vs -4.3%). The detection limit was low for both kits (<1 pmol/l). In the euthyroid reference group (n = 98) we observed a significant difference between outpatient and hospitalized patient FT3 concentrations as measured with the M kit only. Clinical sensitivity for hyperthyroidism (n = 38) was better for the MAB (92%) than for the BM kit (76%). Specificity in euthyroid L-thyroxine (T4) treated patients (n = 26) was good for both kits (MAB: 92%; BM: 88%) . Hypoalbuminemia (n = 8) decreased FT3 results as follows: M, very significantly; BM, significantly; MAB, only slightly. In patients treated with amiodarone (n = 5), a drug known to lower the metabolic conversion ofknown to lower the metabolic conversion of T4 to T3, the increase of the MAB FT3 results contrasted with the decrease of the BM and M results. In conclusion, results of the two new kits were not strongly influenced by hypoalbuminemia. The MAB results showing lack of decrease in patients with non-thyroidal illness without hypoalbuminemia and in amiodarone-treated patients were unexpected

127

In vitro glucose measurement using tunable mid-infrared laser spectroscopy combined with fiber-optic sensor.  

Science.gov (United States)

Because mid-infrared (mid-IR) spectroscopy is not a promising method to noninvasively measure glucose in vivo, a method for minimally invasive high-precision glucose determination in vivo by mid-IR laser spectroscopy combined with a tunable laser source and small fiber-optic attenuated total reflection (ATR) sensor is introduced. The potential of this method was evaluated in vitro. This research presents a mid-infrared tunable laser with a broad emission spectrum band of 9.19 to 9.77[Formula: see text](1024~1088 cm(-1)) and proposes a method to control and stabilize the laser emission wavelength and power. Moreover, several fiber-optic ATR sensors were fabricated and investigated to determine glucose in combination with the tunable laser source, and the effective sensing optical length of these sensors was determined for the first time. In addition, the sensitivity of this system was four times that of a Fourier transform infrared (FT-IR) spectrometer. The noise-equivalent concentration (NEC) of this laser measurement system was as low as 3.8 mg/dL, which is among the most precise glucose measurements using mid-infrared spectroscopy. Furthermore, a partial least-squares regression and Clarke error grid were used to quantify the predictability and evaluate the prediction accuracy of glucose concentration in the range of 5 to 500 mg/dL (physiologically relevant range: 30~400 mg/dL). The experimental results were clinically acceptable. The high sensitivity, tunable laser source, low NEC and small fiber-optic ATR sensor demonstrate an encouraging step in the work towards precisely monitoring glucose levels in vivo. PMID:24466493

Yu, Songlin; Li, Dachao; Chong, Hao; Sun, Changyue; Yu, Haixia; Xu, Kexin

2013-12-17

128

Real-time quantitative fluorescence measurement of microscale cell culture analog systems  

Science.gov (United States)

A microscale cell culture analog (?CCA) is a cell-based lab-on-a-chip assay that, as an animal surrogate, is applied to pharmacological studies for toxicology tests. A ?CCA typically comprises multiple chambers and microfluidics that connect the chambers, which represent animal organs and blood flow to mimic animal metabolism more realistically. A ?CCA is expected to provide a tool for high-throughput drug discovery. Previously, a portable fluorescence detection system was investigated for a single ?CCA device in real-time. In this study, we present a fluorescence-based imaging system that provides quantitative real-time data of the metabolic interactions in ?CCAs with an emphasis on measuring multiple ?CCA samples simultaneously for high-throughput screening. The detection system is based on discrete optics components, with a high-power LED and a charge-coupled device (CCD) camera as a light source and a detector, for monitoring cellular status on the chambers of each ?CCA sample. Multiple samples are characterized mechanically on a motorized linear stage, which is fully-automated. Each ?CCA sample has four chambers, where cell lines MES-SA/DX- 5, and MES-SA (tumor cells of human uterus) have been cultured. All cell-lines have been transfected to express the fusion protein H2B-GFP, which is a human histone protein fused at the amino terminus to EGFP. As a model cytotoxic drug, 10 ?M doxorubicin (DOX) was used. Real-time quantitative data of the intensity loss of enhanced green fluorescent protein (EGFP) during cell death of target cells have been collected over several minutes to 40 hours. Design issues and improvements are also discussed.

Oh, Taek-il; Kim, Donghyun; Tatosian, Daniel; Sung, Jong Hwan; Shuler, Michael

2007-02-01

129

Diamagnetic loop measurements in JT-60U with precision analog integrator  

International Nuclear Information System (INIS)

It is indispensable to evaluate the plasma stored energy accurately in order to investigate energy confinement properties. Although a method based on plasma diamagnetism has difficulties in attaining satisfactory accuracy, it enable us to directly measure the time evolution of the stored energy in every shot. Diamagnetic loops were wound inside the vacuum vessel of JT-60U. The vacuum toroidal flux is compensated by the use of a loop pair with slightly different pick-up areas instead of a Rogowski coil previously adopted for JT-60. The best set with least errors among four sets of diamagnetic loops has been used for routine diamagnetic measurement. The main loop (four turns) and the compensation loop (three turns) are located along a vessel connecting ring to be rigid enough to minimize the variation of the toroidal field coupling. The main and compensating loops are separated by 31 ± 1 mm in the radial direction. The toroidal fluxes through the main and compensating loops in the case of It = 52.1 kA (Bt = 4.0 T at R = 3.32 m) are 96.9 Vs and tc = 76.5 Vs, respectively. Differential integration is made with a precision analog circuit with a potentiometer for the adjustment. Automatic cancellation of input offset voltage is implemented to achieve very low drift. The maximum pulse length of a discharge in JT-60U was extended from 15 s to 65 s in 2003. The excitation of the toroidal magnetic field coils begins 30 s ahead of plasma breakdown so that the integration time is longer than 95 s. With increased electrostatic capacity of a cancellation capacitor, the equivalent input offset voltage is less than 1 V even with an input offset voltage higher than 1 mV. The stray couplings of the loops with poloidal magnetic fields are removed by digital post-processing. The plasma stored energy is calculated by surface integrations with a fast boundary identification code which approximates the plasma current as six filaments or a code based on the Cauchy-condition surface method. The residual error arising from the direct coupling to the plasma current were determined experimentally by sweeping the plasma column vertically or horizontally during low density discharges and by making computed plasma stored energy not to be so positionally sensitive nor to be negative in extremely shifted cases. The absolute error in the dia magnetically measured plasma stored energy [MJ] is estimated to be not more than 0.10 Ip [MA] by comparison with the kinetic stored energy. (author)

130

In vitro glucose measurement using tunable mid-infrared laser spectroscopy combined with fiber-optic sensor  

OpenAIRE

Because mid-infrared (mid-IR) spectroscopy is not a promising method to noninvasively measure glucose in vivo, a method for minimally invasive high-precision glucose determination in vivo by mid-IR laser spectroscopy combined with a tunable laser source and small fiber-optic attenuated total reflection (ATR) sensor is introduced. The potential of this method was evaluated in vitro. This research presents a mid-infrared tunable laser with a broad emission spectrum band of 9.19 to 9.77?m(1024~...

Yu, Songlin; Li, Dachao; Chong, Hao; Sun, Changyue; Yu, Haixia; Xu, Kexin

2013-01-01

131

Photoacoustic blood glucose and skin measurement based on optical scattering effect  

Science.gov (United States)

Non-invasive blood glucose determination has been investigated by more than 100 research groups in the world during the past fifteen years. The commonly optical methods are based on the capacity of near-IR light to penetrate a few hundreds micrometers or a few millimeters into human tissue where it interacts with glucose. A change of glucose concentration may modify the optical parameters in tissue, with the result that its glucose concentration can be extracted by analyzing the received optical signals. This paper demonstrates that glucose affects on the scattering coefficient of human blood, by applying the streak camera and pulsed photoacoustic techniques; and drinking water seems also affecting on PA signal from skin surface.

Zhao, Zuomin; Myllyla, Risto A.

2002-07-01

132

Cerebral blood flow and glucose metabolism measurements in a patient surviving one year after carbon monoxide intoxication.  

Science.gov (United States)

A 29-yr-old woman was studied for 1 yr after acute carbon monoxide intoxication following an attempted suicide by inhalation of automobile exhaust fumes. The patient demonstrated impaired responsiveness to stimuli without any specific neurological deficits for 1 yr after carbon monoxide intoxication. Repeated brain magnetic resonance imaging consistently displayed only bilateral globus pallidus lesions, but no lesions in either deep white matter or cerebral cortex. Position emission tomography measurements of regional cerebral blood flow, and glucose utilization rate were made in this patient at 6 mo and 1 yr following carbon monoxide intoxication. Impairment of both blood flow and glucose metabolism were found not only in the basal ganglia but also in morphologically normal frontal cortex. The decrease in glucose utilization in the frontal cortex was greater than that in the basal ganglia. During the period of 6 mo to 1 yr, blood flow and glucose metabolism in the basal ganglia recovered to the normal range. In the frontal cortex, however, blood flow and glucose metabolism remained approximately 20% lower than the normal mean values. This prolonged dysfunction in the frontal cortex may therefore be responsible for the impaired responsiveness of the subject. PMID:1517846

Shimosegawa, E; Hatazawa, J; Nagata, K; Okudera, T; Inugami, A; Ogawa, T; Fujita, H; Itoh, H; Kanno, I; Uemura, K

1992-09-01

133

Assessing Glucose Uptake through the Yeast Hexose Transporter 1 (Hxt1).  

Science.gov (United States)

The transport of glucose across the plasma membrane is mediated by members of the glucose transporter family. In this study, we investigated glucose uptake through the yeast hexose transporter 1 (Hxt1) by measuring incorporation of 2-NBDG, a non-metabolizable, fluorescent glucose analog, into the yeast Saccharomyces cerevisiae. We find that 2-NBDG is not incorporated into the hxt null strain lacking all glucose transporter genes and that this defect is rescued by expression of wild type Hxt1, but not of Hxt1 with mutations at the putative glucose-binding residues, inferred from the alignment of yeast and human glucose transporter sequences. Similarly, the growth defect of the hxt null strain on glucose is fully complemented by expression of wild type Hxt1, but not of the mutant Hxt1 proteins. Thus, 2-NBDG, like glucose, is likely to be transported into the yeast cells through the glucose transport system. Hxt1 is internalized and targeted to the vacuole for degradation in response to glucose starvation. Among the mutant Hxt1 proteins, Hxt1N370A and HXT1W473A are resistant to such degradation. Hxt1N370A, in particular, is able to neither uptake 2-NBDG nor restore the growth defect of the hxt null strain on glucose. These results demonstrate 2-NBDG as a fluorescent probe for glucose uptake in the yeast cells and identify N370 as a critical residue for the stability and function of Hxt1. PMID:25816250

Roy, Adhiraj; Dement, Angela D; Cho, Kyu Hong; Kim, Jeong-Ho

2015-01-01

134

The relationship between HbA(1c) and fasting plasma glucose in patients with increased plasma liver enzyme measurements  

DEFF Research Database (Denmark)

Background:? HbA(1c) is currently being introduced for diagnostic purpose in diabetes. Previous studies have, however, indicated that patients with liver disease have false low HbA(1c) levels. We therefore investigated the correlation between HbA(1c) and plasma glucose in patients with different levels of increased liver enzyme concentrations. Methods:? Data from 10?065 patients with simultaneous measurement of HbA(1c) , venous fasting plasma glucose, alanine aminotransferase and ?-glutamyl transferase were extracted from our laboratory database. Correlations were investigated in four patient groups divided according to their liver enzyme concentrations. Results:? The correlation between HbA(1c) and plasma glucose was high in all groups, with r?=?0.77 for men and r?=?0.78 for women (P?

Christiansen, R; Rasmussen, L Melholt

2012-01-01

135

Development of a passive air sampler to measure airborne organophosphorus pesticides and oxygen analogs in an agricultural community.  

Science.gov (United States)

Organophosphorus pesticides are some of the most widely used insecticides in the US, and spray drift may result in human exposures. We investigate sampling methodologies using the polyurethane foam passive air sampling device to measure cumulative monthly airborne concentrations of OP pesticides chlorpyrifos, azinphos-methyl, and oxygen analogs. Passive sampling rates (m(3)d(-1)) were determined using calculations using chemical properties, loss of depuration compounds, and calibration with side-by-side active air sampling in a dynamic laboratory exposure chamber and in the field. The effects of temperature, relative humidity, and wind velocity on outdoor sampling rates were examined at 23 sites in Yakima Valley, Washington. Indoor sampling rates were significantly lower than outdoors. Outdoor rates significantly increased with average wind velocity, with high rates (>4m(3)d(-1)) observed above 8ms(-1). In exposure chamber studies, very little oxygen analog was observed on the PUF-PAS, yet substantial amounts chlorpyrifos-oxon and azinphos methyl oxon were measured in outdoor samples. PUF-PAS is a practical and useful alternative to AAS because it results in little artificial transformation to the oxygen analog during sampling, it provides cumulative exposure estimates, and the measured sampling rates were comparable to rates for other SVOCs. It is ideal for community based participatory research due to low subject burden and simple deployment in remote areas. PMID:24997910

Armstrong, Jenna L; Yost, Michael G; Fenske, Richard A

2014-09-01

136

Estimation of utility values from visual analog scale measures of health in patients undergoing cardiac surgery  

Directory of Open Access Journals (Sweden)

Full Text Available Lars Oddershede,1,2 Jan Jesper Andreasen,1 Lars Ehlers2 1Department of Cardiothoracic Surgery, Center for Cardiovascular Research, Aalborg University Hospital, Aalborg, Denmark; 2Danish Center for Healthcare Improvements, Faculty of Social Sciences and Faculty of Health Sciences, Aalborg University, Aalborg East, Denmark Introduction: In health economic evaluations, mapping can be used to estimate utility values from other health outcomes in order to calculate quality adjusted life-years. Currently, no methods exist to map visual analog scale (VAS scores to utility values. This study aimed to develop and propose a statistical algorithm for mapping five dimensions of health, measured on VASs, to utility scores in patients suffering from cardiovascular disease. Methods: Patients undergoing coronary artery bypass grafting at Aalborg University Hospital in Denmark were asked to score their health using the five VAS items (mobility, self-care, ability to perform usual activities, pain, and presence of anxiety or depression and the EuroQol 5 Dimensions questionnaire. Regression analysis was used to estimate four mapping models from patients' age, sex, and the self-reported VAS scores. Prediction errors were compared between mapping models and on subsets of the observed utility scores. Agreement between predicted and observed values was assessed using Bland–Altman plots. Results: Random effects generalized least squares (GLS regression yielded the best results when quadratic terms of VAS scores were included. Mapping models fitted using the Tobit model and censored least absolute deviation regression did not appear superior to GLS regression. The mapping models were able to explain approximately 63%–65% of the variation in the observed utility scores. The mean absolute error of predictions increased as the observed utility values decreased. Conclusion: We concluded that it was possible to predict utility scores from VAS scores of the five dimensions of health used in the EuroQol questionnaires. However, the use of the mapping model may be inappropriate in more severe conditions. Keywords: coronary artery bypass grafts, mapping, cross-walk, quality of life, outcomes research

Oddershede L

2014-01-01

137

Measurement of glucose metabolism in patients with dilated cardiomyopathy using positron emission tomography with 18F-FDG: Initial Experience  

International Nuclear Information System (INIS)

Introduction: Fluorine18 deoxyglucose (18F-FDG) has been used in numerous studies to determine the cardiac rate of glucose metabolism in normal and pathological conditions. It is known that during heart failure the metabolic pattern is altered. Patlack's graphical analysis allows the assessment of heart muscle glucose consumption in patients with non-ischaemic heart failure and normal subjects. Methods: Standardized measurement of glucose metabolism was performed in four patients with dilated cardiomyopathy and three healthy subjects. All subjects received an oral load of carbohydrates (75gr) previous to scanning. Dynamic images of the thorax were acquired. Myocardial uptake was estimated from time-activity curves in the atrium and left ventricle using Patlack's graphical analysis. Results: All subjects studied were male. 18F-FDG uptake rate for the group with dilated cardiomyopathy was 1.31±0.2, versus 1.26±0.37 ml/100gr/min in the control group. Conclusion: Measurement of cardiac glucose metabolism by 18F-FDG PET is feasible in a clinical service, allowing impact evaluation of physiologic and metabolic changes in the myocardium in different pathologic scenarios in addition to therapy assessment

138

Measurement of regional cerebral glucose utilization in man by positron emission tomography  

International Nuclear Information System (INIS)

The various methods available for the study of regional cerebral glucose consumption in man by positron emission tomography are described and their applications, limitations and principal physiopathological results are presented

139

Experimental study for cancer diagnosis with positron-labeled fluorinated glucose analogs: [18F]-2-fluoro-2-deoxy-D-mannose  

International Nuclear Information System (INIS)

18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) and 18F-2-fluoro-2-deoxy-D-mannose (18F-FDM) were tested as tumor diagnostic agents in a transplantable rat tumor and rabbit tumors. Tissue distribution studies in rats showed high tumor uptakes of both radiopharmaceuticals. The tumor uptake reached 2.65+-0.61% dose 18F-FDG/g and 2.65+-0.81% dose 18F-FDM/g at 60 min and remained relatively constant until 120 min. Blood clearance of both 18F-FDG and 18F-FDM was very rapid and tumor-to-blood ratios reached 22.1 and 29.4 at 60 min, respectively. Tumor-to-tissue ratios of both radiopharmaceuticals were very high in most organs, especially in the liver, kidney, and pancreas. Positron emission tomography (PET) of rabbit tumor with 18F-FDM clearly delineated the main tumor, central necrosis, and lymph node metastases. These data suggested that 18F-FDM, which is a by-product of 18F-FDG synthesis, was also an excellent cancer diagnostic agent as well as 18-F-FDG. This is not only a new feature of 18F-FDM, but also an economical improvement on cancer diagnosis by PET. (orig.)

140

Intracellular Glucose Concentration in Derepressed Yeast Cells Consuming Glucose Is High Enough To Reduce the Glucose Transport Rate by 50%  

OpenAIRE

In Saccharomyces cerevisiae cells exhibiting high-affinity glucose transport, the glucose consumption rate at extracellular concentrations above 10 mM was only half of the zero trans-influx rate. To determine if this regulation of glucose transport might be a consequence of intracellular free glucose we developed a new method to measure intracellular glucose concentrations in cells metabolizing glucose, which compares glucose stereoisomers to correct for adhering glucose. The intracellular gl...

Teusink, Bas; Diderich, Jasper A.; Westerhoff, Hans V.; Dam, Karel; Walsh, Michael C.

1998-01-01

141

Synthesis and anticancer activity of new flavonoid analogs and inconsistencies in assays related to proliferation and viability measurements.  

Science.gov (United States)

Flavonoids have been studied intensely for their ability to act as anti-carcinogenic, anti-inflammatory, anti-viral and anti-aging agents and are often marketed as supplements related to their anti-inflammatory activity. Previous studies have primarily focused on the effects of polar natural flavonoids. We examined the activity of novel hydrophobic and lipophilic flavonols against human DU-145 and PC-3 prostate cancer cell lines. All flavonol analogs were more active than the naturally occurring flavonols quercetin, kaempferol, kaempferide and galangin. The most potent analogs were 6.5-fold more active against DU-145 and PC-3 cells than quercetin and fell within the biologically relevant concentration range (low micromolar). We also evaluated the potential toxic effects of flavonol analogs on normal cells, an assessment that has frequently been ignored when studying the anticancer effects of flavonoids. During these analyses, we discovered that various metabolic and DNA staining assays were unreliable methods for assessing cell viability of flavonoids. Flavonoids reduce colorimetric dyes such as MTT and Alamar Blue in the absence of cells. We showed that flavonol-treated prostate cancer cells were stained less intensely with crystal violet than untreated cells at non-toxic concentrations. The trypan blue exclusion assay was selected as a reliable alternative for measuring cell viability. PMID:24859601

Forbes, Alaina M; Lin, Huimin; Meadows, Gary G; Meier, G Patrick

2014-08-01

142

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1985-05-01

143

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

International Nuclear Information System (INIS)

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

144

Developmental expression of the glucose transporter in brain microvessels  

International Nuclear Information System (INIS)

Brain microvessels were isolated from late gestation fetal (55-68 days), newborn (5-9 day old) and adult guinea pigs. Glucose transport was assessed by measuring the initial uptake of [3H]-2-deoxy-D-glucose, a glucose analog that is transported and phosphorylated but not further metabolized. At 22C and substrate concentrations of 40 mM, uptakes were linear for 8 minutes. The data reported here were uptakes over the first 2 minutes. 2-deoxy-D-glucose uptake was 3.5 fold higher in newborn microvessels, 99.5±18.4 (SEM) fmols/mg protein/2 minutes, compared to fetal, 27.8±7.9. The number of glucose transporters was estimated using the [3H] cytochalasin B which can be displaced by D-glucose (250 mM). Binding at 35 nM cytochalasin B was higher in newborn brain microvessels (8.2±1.6 pmole/mg protein) than in fetal (3.4±1.1) or adult (2.8±0.6) brain microvessels. Initial RNA blot experiments using a cDNA for the brain/erythrocyte (HepG2) glucose transporter show increased expression in newborn microvessels compared to the fetus or the adult. The authors conclude that the brain microvessel glucose transporter is increased in the newborn period

145

Effective Dynamic Range in Measurements with Flash Analog-to-Digital Convertor  

CERN Document Server

Flash Analog to Digital Convertor (FADC) is frequently used in nuclear and particle physics experiments, often as the major component in big multi-channel systems. The large data volume makes the optimization of operating parameters necessary. This article reports a study of a method to extend the dynamic range of an 8-bit FADC from the nominal $\\rm{2^8}$ value. By comparing the integrated pulse area with that of a reference profile, good energy reconstruction and event identification can be achieved on saturated events from CsI(Tl) crystal scintillators. The effective dynamic range can be extended by at least 4 more bits. The algorithm is generic and is expected to be applicable to other detector systems with FADC readout.

Yue, Q

2003-01-01

146

Effective dynamic range in measurements with flash analog-to-digital convertor  

Science.gov (United States)

Flash Analog-to-Digital Convertor (FADC) is frequently used in Nuclear and Particle Physics experiments, often as the major component in big multi-channel systems. The large data volume makes the optimization of operating parameters necessary. This article reports a study of a method to extend the dynamic range of an 8-bit FADC from the nominal 2 8 value. By comparing the integrated pulse area with that of a reference profile, good energy reconstruction and event identification can be achieved on saturated events from CsI(Tl) crystal scintillators. The effective dynamic range can be extended by at least four more bits. The algorithm is generic and is expected to be applicable to other detector systems with FADC readout.

Yue, Q.; Lai, W. P.; Chang, W. C.; Li, H. B.; Li, J.; Lin, S. T.; Liu, D. Z.; Qiu, J. F.; Singh, V.; Wong, H. T.

2003-10-01

147

Oxidative activity of hydroxylated primaquine analogs. Non-toxicity to glucose-6-phosphate dehydrogenase-deficient human red blood cells in vitro.  

OpenAIRE

The individual effects of two putative metabolites of primaquine (5,6-dihydroxyprimaquine and 5,6-dihydroxy-8-aminoquinoline) on the hexose monophosphate shunt (HMS) and on the ATP-dependent proteolytic system which rapidly degrades oxidized erythrocyte protein were measured in intact red blood cells in vitro from two blood donors. In red cells treated with nitrite (1-40 mM) or phenylhydrazine (0.01-10 mM), proteolytic activity was detected only with concentrations (7.5 mM NaNO2 and 0.25 mM p...

Baird, Jk; Davidson, DE; Decker-jackson, Je

1986-01-01

148

Continuous and simultaneous electrochemical measurements of glucose, lactate, and ascorbate in rat brain following brain ischemia.  

Science.gov (United States)

Developing new tools and technologies to enable recording the dynamic changes of multiple neurochemicals is the essence of better understanding of the molecular basis of brain functions. This study demonstrates a microfluidic chip-based online electrochemical system (OECS) for in vivo continuous and simultaneous monitoring of glucose, lactate, and ascorbate in rat brain. To fabricate the microfluidic chip-based detecting system, a microfluidic chip with patterned channel is developed into an electrochemical flow cell by incorporating the chip with three surface-modified indium-tin oxide (ITO) electrodes as working electrodes, a Ag/AgCl wire as reference electrode, and a stainless steel tube as counter electrode. Selective detection of ascorbate is achieved by the use of single-walled carbon nanotubes (SWNTs) to largely facilitate the electrochemical oxidation of ascorbate, while a dehydrogenase-based biosensing mechanism with methylene green (MG) adsorbed onto SWNTs as an electrocatalyst for the oxidation of dihydronicotiamide adenine dinucleotide (NADH) is employed for biosensing of glucose and lactate. To avoid the crosstalk among three sensors, the sensor alignment is carefully designed with the SWNT-modified electrode in the upstream channel and paralleled glucose and lactate biosensors in the downstream channels. With the microfluidic chip-based electrochemical flow cell as the detector, an OECS is successfully established by directly integrating the microfluidic chip-based electrochemical flow cell with in vivo microdialysis. The OECS exhibits a good linear response toward glucose, lactate, and ascorbate with less crosstalk. This property, along with the high stability and selectivity, enables the OECS for continuously monitoring three species in rat brain following brain ischemia. PMID:24621127

Lin, Yuqing; Yu, Ping; Hao, Jie; Wang, Yuexiang; Ohsaka, Takeo; Mao, Lanqun

2014-04-15

149

Glucose Sensing  

CERN Document Server

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...

Geddes, Chris D

2006-01-01

150

Precision timing measurement of phototube pulses using a flash analog-to-digital converter  

OpenAIRE

We present the timing characteristics of the flash ADC readout of the GlueX forward calorimeter, which depends on precise measurement of arrival time of pulses from FEU 84-3 photomultiplier tubes to suppress backgrounds. The tests presented were performed using two different 250 MHz prototype flash ADC devices, one with eight-bit and one with twelve-bit sampling depth. All measured time resolutions were better than 1 ns, independent of signal size, which is the design goal f...

Bennett, J. V.; Kornicer, M.; Shepherd, M. R.; Ito, M. M.

2010-01-01

151

Utility and validity of a single-item visual analog scale for measuring dental anxiety in clinical practice.  

Science.gov (United States)

We evaluated whether a visual analog scale (VAS) was comparable to the multi-item Modified Dental Anxiety Scale (MDAS) in assessing dental anxiety in clinical practice. In total, 200 consecutive patients aged 20-70 years who presented at the dental outpatient department of SRM Dental College, Chennai were enrolled. The test-retest value for the VAS was 0.968. The Spearman rank correlations between the VAS and MDAS items and total score were significant (P dental visit and the VAS also showed a strong correlation (r = 0.473, P dental phobia. The weighted kappa was 69% for agreement between MDAS and the VAS in identifying patients with and without dental anxiety at cut-offs of 13 and 4.75, respectively. The VAS was found to be a valid measure and was comparable to the multi-item MDAS. PMID:24930752

Appukuttan, Devapriya; Vinayagavel, Mythreyi; Tadepalli, Anupama

2014-01-01

152

An analog and time digitizer for two-dimensional data acquisition for time-of-flight measurements  

Science.gov (United States)

A CAMAC module has been developed to record simultaneously the pulse height and the elapsed time of an event following a start signal. The module is based on an 8-bit (256-channel) 100 MHz fast analog to digital converter (FADC) and a 16-bit (65536-channel) time digitizer with a maximum time range of 4.9 ms and a minimum resolving time of 20 ns. A short dead time in the data acquisition equipment is required to keep count loss corrections to an acceptable level at high count rates. The processing of the signal including storage of the data in a 256-word buffer takes place during the 10 ns dead time of the module. A built-in digital to analog converter (DAC) can be used to set up and test the module. The unit can be used in several different ways, for example (a) as a multiparameter neutron time-of-flight spectrometer, (b) as a transient wave recorder with a continuous read-in, (c) as a transient wave recorder with a 16-block read-in and (d) as a self-triggering digital discriminator. In this report a description is given of the use of the system in neutron transmission measurements using the pulsed neutron source HELIOS at Harwell. In these measurements the count rates were several times the highest count rate previously recorded on such experiments at Harwell. The count loss and background were more easily and more accurately calculated from the information gained from the two-dimensional recording of the data.

Schmiedmayer, J.; Pernicka, M.; Moxon, M. C.

1989-03-01

153

An analog and time digitizer for two-dimensional data acquisition for time-of-flight measurements  

International Nuclear Information System (INIS)

A CAMAC module has been developed to record simultaneously the pulse height and the elapsed time of an event following a start signal. The module is based on an 8-bit (256-channel) 100 MHz fast analog to digital converter (FADC) and a 16-bit (65536-channel) time digitizer with a maximum time range of 4.9 ms and a minimum resolving time of 20 ns. A short dead time in the data acquisition equipment is required to keep count loss corrections to an acceptable level at high count rates. The processing of the signal including storage of the data in 256-word buffer takes place during the 10 ns dead time of the module. A built-in digital to analog converter (DAC) can be used to set up and test the module. The unit can be used in several different ways, for example 1. as a multiparameter neutron time-of-flight spectrometer, 2. as a transient wave recorder with a continuous read-in, 3. as a transient wave recorder with a 16-block read-in and 4. as a self-triggering digital discriminator. In this report a description is given of the use of the system in neutron transmission measurements using the pulsed neutron source HELIOS at Harwell. In these measurements the count rates were several times the highest count rate previously recorded on such experiments at Harwell. The count loss and background were more easily and more accurately calculated from the information gained from the two-dimensional recording of the data. (orig.)

154

Measurement of the thermal spectrum of Hawking radiation from analog horizon  

International Nuclear Information System (INIS)

Full text: In 1974 Hawking predicted that black holes should radiate thermal radiation with a temperature given by the geometry of the horizon. In 1980 I suggested that this was a far more universal phenomenon and applied to horizons in many other situations, In 2010 we at Univ of BC measured the spectrum of the quantum radiation from a horizon to surface waves in water flow, by measuring the amplification of waves which impinged on that horizon. The spectrum of the associated quantum noise was shown that it would be thermal and Temperature determined by the characteristics of the flow as expected from the above arguments. (author)

155

Measurement of the thermal spectrum of Hawking radiation from analog horizon  

Energy Technology Data Exchange (ETDEWEB)

Full text: In 1974 Hawking predicted that black holes should radiate thermal radiation with a temperature given by the geometry of the horizon. In 1980 I suggested that this was a far more universal phenomenon and applied to horizons in many other situations, In 2010 we at Univ of BC measured the spectrum of the quantum radiation from a horizon to surface waves in water flow, by measuring the amplification of waves which impinged on that horizon. The spectrum of the associated quantum noise was shown that it would be thermal and Temperature determined by the characteristics of the flow as expected from the above arguments. (author)

Unruh, William [British Columbia University (Canada)

2013-07-01

156

Measurement of Faraday rotation in twisted optical fiber using rotating polarization and analog phase detection  

International Nuclear Information System (INIS)

We demonstrated phase modulation of rotating linearly polarized light by current-induced Faraday rotation in a single mode optical fiber and used the technique to measure the current in ZT-40M, a Reversed-Field Pinch. We have also demonstrated the practicality of using twisted sensing fiber to overcome the problems associated with linear birefringence

157

Laser spectroscopic real time measurements of methanogenic activity under simulated Martian subsurface analog conditions  

Science.gov (United States)

On Earth, chemolithoautothrophic and anaerobic microorganisms such as methanogenic archaea are regarded as model organisms for possible subsurface life on Mars. For this reason, the methanogenic strain Methanosarcina soligelidi (formerly called Methanosarcina spec. SMA-21), isolated from permafrost-affected soil in northeast Siberia, has been tested under Martian thermo-physical conditions. In previous studies under simulated Martian conditions, high survival rates of these microorganisms were observed. In our study we present a method to measure methane production as a first attempt to study metabolic activity of methanogenic archaea during simulated conditions approaching conditions of Mars-like environments. To determine methanogenic activity, a measurement technique which is capable to measure the produced methane concentration with high precision and with high temporal resolution is needed. Although there are several methods to detect methane, only a few fulfill all the needed requirements to work within simulated extraterrestrial environments. We have chosen laser spectroscopy, which is a non-destructive technique that measures the methane concentration without sample taking and also can be run continuously. In our simulation, we detected methane production at temperatures down to -5 °C, which would be found on Mars either temporarily in the shallow subsurface or continually in the deep subsurface. The pressure of 50 kPa which we used in our experiments, corresponds to the expected pressure in the Martian near subsurface. Our new device proved to be fully functional and the results indicate that the possible existence of methanogenic archaea in Martian subsurface habitats cannot be ruled out.

Schirmack, Janosch; Böhm, Michael; Brauer, Chris; Löhmannsröben, Hans-Gerd; de Vera, Jean-Pierre; Möhlmann, Diedrich; Wagner, Dirk

2014-08-01

158

Glucose metabolism of fetal rat brain in utero, measured with labeled deoxyglucose  

International Nuclear Information System (INIS)

Mammals have low cerebral metabolic rates immediately after birth and, by inference, also before birth. In this study, we extended the deoxyglucose method to the fetal rat brain in utero. Rate constants for deoxyglucose transfer across the maternal placental and fetal blood-brain barriers, and lumped constant, have not been reported. Therefore, we applied a new method of determining the lumped constant regionally to the fetal rat brain in utero. The lumped constant averaged 0.55 ± 0.15 relative to the maternal circulation. On this basis, we determined the glucose metabolic rate of the fetal rat brain to be one third of the corresponding maternal value, or 19 ± 2 ?mol hg-1 min-1. (author)

159

CMOS image sensors as an efficient platform for glucose monitoring.  

Science.gov (United States)

Complementary metal oxide semiconductor (CMOS) image sensors have been used previously in the analysis of biological samples. In the present study, a CMOS image sensor was used to monitor the concentration of oxidized mouse plasma glucose (86-322 mg dL(-1)) based on photon count variation. Measurement of the concentration of oxidized glucose was dependent on changes in color intensity; color intensity increased with increasing glucose concentration. The high color density of glucose highly prevented photons from passing through the polydimethylsiloxane (PDMS) chip, which suggests that the photon count was altered by color intensity. Photons were detected by a photodiode in the CMOS image sensor and converted to digital numbers by an analog to digital converter (ADC). Additionally, UV-spectral analysis and time-dependent photon analysis proved the efficiency of the detection system. This simple, effective, and consistent method for glucose measurement shows that CMOS image sensors are efficient devices for monitoring glucose in point-of-care applications. PMID:23900281

Devadhasan, Jasmine Pramila; Kim, Sanghyo; Choi, Cheol Soo

2013-10-01

160

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

International Nuclear Information System (INIS)

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 (CMRGlcreal). Simulated input functions were generated based on standardised input function, body surface area and net injected dose of FDG, and simulated CMRGlc (CMRGlcsim) was also calculated. Percent error of the area under the curve (AUC) between measured (AUCreal) and simulated input function (AUCIFsim) and percent error between CMRGlcreal and CMRGlcsim 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-invasivIt is concluded that a non-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions. (orig.)

161

Analog multivariate counting analyzers  

CERN Document Server

Characterizing rates of occurrence of various features of a signal is of great importance in numerous types of physical measurements. Such signal features can be defined as certain discrete coincidence events, e.g. crossings of a signal with a given threshold, or occurrence of extrema of a certain amplitude. We describe measuring rates of such events by means of analog multivariate counting analyzers. Given a continuous scalar or multicomponent (vector) input signal, an analog counting analyzer outputs a continuous signal with the instantaneous magnitude equal to the rate of occurrence of certain coincidence events. The analog nature of the proposed analyzers allows us to reformulate many problems of the traditional counting measurements, and cast them in a form which is readily addressed by methods of differential calculus rather than by algebraic or logical means of digital signal processing. Analog counting analyzers can be easily implemented in discrete or integrated electronic circuits, do not suffer fro...

Nikitin, A V; Armstrong, T P

2003-01-01

162

Experimentally Measured Interfacial Area during Gas Injection into Saturated Porous Media: An Air Sparging Analogy  

Energy Technology Data Exchange (ETDEWEB)

The amount of interfacial area (awn) between air and subsurface liquids during air-sparging can limit the rate of site remediation. Lateral movement within porous media could be encountered during air-sparging operations when air moves along the bottom of a low-permeability lens. This study was conducted to directly measure the amount of awn between air and water flowing within a bench-scale porous flow cell during the lateral movement of air along the upper edge of the cell during air injections into an initially water-saturated flow cell. Four different cell orientations were used to evaluate the effect of air injection rates and porous media geometries on the amount of awn between fluids. Air was injected at flow rates that varied by three orders of magnitude, and for each flow cellover this range of injection rates little change in awn was noted. A wider variation in awn was observed when air moved through different regions for the different flow cell orientations. These results are in good agreement with the experimental findings of Waduge et al. (2007), who performed experiments in a larger sand-pack flow cell, and determined that air-sparging efficiency is nearly independent of flow rate but highly dependent on the porous structure. By directly measuring the awn, and showing that awn does not vary greatly with changes in injection rate, we show that the lack of improvement to remediation rates is because there is a weak dependence of the awn on the air injection rate.

Crandall, Dustin; Ahmadi, Goodarz; Smith, Duane H., Bromhal, Grant

2010-01-01

163

Leishmania amazonensis chemotaxis under glucose gradient studied by the strength and directionality of forces measured with optical tweezers  

Science.gov (United States)

Chemotaxis is the mechanism microorganisms use to sense the environment surrounding them and to direct their movement towards attractive, or away from the repellent, chemicals. The biochemical sensing is almost the only way for communication between unicellular organisms. Prokaryote and Eukaryote chemotaxis has been mechanically studied mainly by observing the directionality and timing of the microorganisms movements subjected to a chemical gradient, but not through the directionality and strength of the forces it generates. To observe the vector force of microorganisms under a chemical gradient we developed a system composed of two large chambers connected by a tiny duct capable to keep the chemical gradient constant for more than ten hours. We also used the displacements of a microsphere trapped in an Optical Tweezers as the force transducer to measure the direction and the strength of the propulsion forces of flagellum of the microorganism under several gradient conditions. A 9?m diameter microsphere particle was trapped with a Nd:YAG laser and its movement was measured through the light scattered focused on a quadrant detector. We observed the behavior of the protozoa Leishmania amazonensis (eukaryote) under several glucose gradients. This protozoa senses the gradient around it by swimming in circles for three to five times following by tumbling, and not by the typical straight swimming/tumbling of bacteria. Our results also suggest that force direction and strength are also used to control its movement, not only the timing of swimming/tumbling, because we observed a higher force strength clearly directed towards the glucose gradient.

de Ysasa Pozzo, Liliana; Fontes, Adriana; de Thomaz, André A.; Barbosa, Luiz Carlos; Ayres, Diana Copi; Giorgio, Selma; Cesar, Carlos Lenz

2007-02-01

164

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)

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 (18F)-2-deoxy-2-fluoro-D-glucose (FDG) and positron ECT. Our model incorporates a k4* mediated hydrolysis of FDG-6-PO4 to FDG which then competes with phosphorylation (k3*) of FDG back to FDG-6-PO4 and reverse transport (k2*) back to blood. Although small, k4* is found to be significant. The ECAT positron tomograph was used to measure the rate constants (k1*?k4*), 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-PO4 were determined and show that cerebral FDG-6-PO4 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

165

Allosteric regulation of the glucose:H+ symporter of Lactobacillus brevis: cooperative binding of glucose and HPr(ser-P).  

OpenAIRE

Lactobacillus brevis transports glucose and the nonmetabolizable glucose analog 2-deoxyglucose via a proton symport mechanism that is allosterically inhibited by the seryl-phosphorylated derivative of HPr, the small phosphocarrier protein of the phosphotransferase system. We have demonstrate that S46DHPr, a mutant analog of HPr which conformationally resembles HPr(ser-P) but not free HPr, specifically binds to membranes derived from glucose-grown L. brevis cells if and only if a substrate of ...

Ye, J. J.; Saier, M. H.

1995-01-01

166

High glucose concentrations partially release hexokinase from inhibition by glucose 6-phosphate.  

OpenAIRE

The phosphorylation of glucose by human erythrocyte hexokinase follows classical Michaelis-Menten kinetics; hexokinase manifests maximum activity at 5 mM glucose, and no further increase in activity can be measured at higher glucose concentrations. However, the erythrocytes of diabetics and normal erythrocytes incubated with high concentrations of glucose contain increased concentrations of glucose 6-phosphate. To elucidate the mechanism of accumulation of glucose 6-phosphate when erythrocyte...

Fujii, S.; Beutler, E.

1985-01-01

167

Employment of Item Response Theory to measure change in Children's Analogical Thinking Modifiability Test / Emprego da Teoria de Resposta do Item para medida de mudança no Children's Analogical Thinking Modifiability Test  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Provas assistidas, com fase intermediária de ensino, medem mudanças entre pré-teste e pós-teste pressupondo uma métrica comum entre eles. Para testar este pressuposto, aplicou-se a Teoria de Resposta ao Item nas respostas de 69 crianças à prova cognitiva assistida Children's Analogical Thinking Modi [...] fiability Test adaptada, com 12 itens, totalizando 828 respostas, para verificar se a escala original produzia os mesmos resultados em termos de quantificação de mudança que a escala equalizada obtida via Teoria de Resposta ao Item. Seguiram-se os passos: 1) ancoragem dos itens de pré e pós-teste, por uma análise cognitiva, encontrando-se três itens em comum; 2) estimação do parâmetro de dificuldade dos itens e comparação destes; 3) equalização dos itens e estimação dos "thetas"; 4) comparação das escalas. A métrica do Children's Analogical Thinking Modifiability Test foi semelhante à estimada pela Teoria de Resposta ao Item, mas é preciso diferenciar a dificuldade dos itens de pré e pós-teste, adequando-o a amostras com alto e baixo desempenho. Abstract in english Dynamic testing, with an intermediate phase of assistance, measures changes between pretest and post-test assuming a common metric between them. To test this assumption we applied the Item Response Theory in the responses of 69 children to dynamic cognitive testing Children's Analogical Thinking Mod [...] ifiability Test adapted, with 12 items, totaling 828 responses, with the purpose of verifying if the original scale yields the same results as the equalized scale obtained by Item Response Theory in terms of "changes quantifying". We followed the steps: 1) anchorage of the pre and post-test items through a cognitive analysis, finding 3 common items; 2) estimation of the items' difficulty level parameter and comparison of those; 3) equalization of the items and estimation of "thetas"; 4) comparison of the scales. The Children's Analogical Thinking Modifiability Test metric was similar to that estimated by the TRI, but it is necessary to differentiate the pre and post-test items' difficulty, adjusting it to samples with high and low performance.

Odoisa Antunes de, Queiroz; Ricardo, Primi; Lucas de Francisco, Carvalho; Sônia Regina Fiorim, Enumo.

2013-12-01

168

Infrared spectroscopic analysis of human interstitial fluid in vitro and in vivo using FT-IR spectroscopy and pulsed quantum cascade lasers (QCL): Establishing a new approach to non invasive glucose measurement  

Science.gov (United States)

Interstitial fluid, i.e. the liquid present in the outermost layer of living cells of the skin between the Stratum corneum and the Stratum spinosum, was analyzed by Fourier transform infrared spectroscopy and by infrared spectroscopy using pulsed quantum cascade infrared lasers with photoacoustic detection. IR spectra of simulated interstitial fluid samples and of real samples from volunteers in the 850-1800 cm -1 range revealed that the major components of interstitial fluid are albumin and glucose within the physiological range, with only traces of sodium lactate if at all. The IR absorbance of glucose in interstitial fluid in vivo was probed in healthy volunteers using a setup with quantum cascade lasers and photoacoustic detection previously described [11]. A variation of blood glucose between approx. 80 mg/dl and 250 mg/dl in the volunteers was obtained using the standard oral glucose tolerance test (OGT). At two IR wavelengths, 1054 cm -1 and 1084 cm -1, a reasonable correlation between the photoacoustic signal from the skin and the blood glucose value as determined by conventional glucose test sticks using blood from the finger tip was obtained. The infrared photoacoustic glucose signal (PAGS) may serve as the key for a non-invasive glucose measurement, since the glucose content in interstitial fluid closely follows blood glucose in the time course and in the level (a delay of some minutes and a level of approx. 80-90% of the glucose level in blood). Interstitial fluid is present in skin layers at a depth of only 15-50 ?m and is thus within the reach of mid-IR energy in an absorbance measurement. A non-invasive glucose measurement for diabetes patients based on mid-infrared quantum cascade lasers and photoacoustic detection could replace the conventional measurement using enzymatic test stripes and a drop of blood from the finger tip, thus reducing pain and being a cost-efficient alternative for millions of diabetes patients.

Pleitez, Miguel; von Lilienfeld-Toal, Hermann; Mäntele, Werner

2012-01-01

169

Quantitative measurements of regional glucose utilization and rate of valine incorporation into proteins by double-tracer autoradiography in the rat brain tumor model  

International Nuclear Information System (INIS)

We examined the rate of glucose utilization and the rate of valine incorporation into proteins using 2-[18F]fluoro-2-deoxyglucose and L-[1-14C]-valine in a rat brain tumor model by quantitative double-tracer autoradiography. We found that in the implanted tumor the rate of valine incorporation into proteins was about 22 times and the rate of glucose utilization was about 1.5 times that in the contralateral cortex. (In the ipsilateral cortex, the tumor had a profound effect on glucose utilization but no effect on the rate of valine incorporation into proteins.) Our findings suggest that it is more useful to measure protein synthesis than glucose utilization to assess the effectiveness of antitumor agents and their toxicity to normal brain tissue. We compared two methods to estimate the rate of valine incorporation: kinetic (quantitation done using an operational equation and the average brain rate coefficients) and washed slices (unbound labeled valine removed by washing brain slices in 10% trichloroacetic acid). The results were the same using either method. It would seem that the kinetic method can thus be used for quantitative measurement of protein synthesis in brain tumors and normal brain tissue using [11C]-valine with positron emission tomography

170

A Low Frequency Electromagnetic Sensor for Indirect Measurement of Glucose Concentration: In Vitro Experiments in Different Conductive Solutions  

Directory of Open Access Journals (Sweden)

Full Text Available In recent years there has been considerable interest in the study of glucose-induced dielectric property variations of human tissues as a possible approach for non-invasive glycaemia monitoring. We have developed an electromagnetic sensor, and we tested in vitro its ability to estimate variations in glucose concentration of different solutions with similarities to blood (sodium chloride and Ringer-lactate solutions, differing though in the lack of any cellular components. The sensor was able to detect the effect of glucose variations over a wide range of concentrations (~78–5,000 mg/dL, with a sensitivity of ~0.22 mV/(mg/dL. Our proposed system may thus be useful in a new approach for non-invasive and non-contact glucose monitoring.

Andrea Tura

2010-05-01

171

Direct evidence for activity-dependent glucose phosphorylation in neurons with implications for the astrocyte-to-neuron lactate shuttle.  

Science.gov (United States)

Previous (13)C magnetic resonance spectroscopy experiments have shown that over a wide range of neuronal activity, approximately one molecule of glucose is oxidized for every molecule of glutamate released by neurons and recycled through astrocytic glutamine. The measured kinetics were shown to agree with the stoichiometry of a hypothetical astrocyte-to-neuron lactate shuttle model, which predicted negligible functional neuronal uptake of glucose. To test this model, we measured the uptake and phosphorylation of glucose in nerve terminals isolated from rats infused with the glucose analog, 2-fluoro-2-deoxy-D-glucose (FDG) in vivo. The concentrations of phosphorylated FDG (FDG6P), normalized with respect to known neuronal metabolites, were compared in nerve terminals, homogenate, and cortex of anesthetized rats with and without bicuculline-induced seizures. The increase in FDG6P in nerve terminals agreed well with the increase in cortical neuronal glucose oxidation measured previously under the same conditions in vivo, indicating that direct uptake and oxidation of glucose in nerve terminals is substantial under resting and activated conditions. These results suggest that neuronal glucose-derived pyruvate is the major oxidative fuel for activated neurons, not lactate-derived from astrocytes, contradicting predictions of the original astrocyte-to-neuron lactate shuttle model under the range of study conditions. PMID:24706914

Patel, Anant B; Lai, James C K; Chowdhury, Golam M I; Hyder, Fahmeed; Rothman, Douglas L; Shulman, Robert G; Behar, Kevin L

2014-04-01

172

Fictitious hyperglycemia: point-of-care glucose measurement is inaccurate during high-dose vitamin C infusion for burn shock resuscitation.  

Science.gov (United States)

The use of high-dose vitamin C (hdVC, 66 mg/kg/hour × 18 hours) infusion is a useful adjunct to reducing fluid requirements during resuscitation of burn shock. Routine point-of-care glucose (POCG) analysis has been inaccurately high in observed patients undergoing hdVC. Inaccurate POCG could potentially lead to iatrogenic hypoglycemia if the fictitious hyperglycemia is treated with insulin. This study is a retrospective analysis of plasma glucose measurements from a central laboratory (LG) compared with POCG during and 24 hours after hdVC infusion. Records of adult patients receiving hdVC infusions during burn resuscitation over 1 year were reviewed. Charts selected for analysis included those with glucose measurements using POCG and LG that were taken simultaneously, during hdVC infusion, and 24 hours after completion. All specimens were drawn from arterial lines. POCG was measured with Accu-Chek Inform (Roche, Indianapolis, IN) and LG was measured by Siemens Dimension Vista 500 (Siemens, Deerfield, IL) using biochromic analysis. Nonparametric statistical analysis was performed using Wilcoxon's matched pairs test and Spearman correlation with significance at P < .05. Of 18 adult patients undergoing burn resuscitation with hdVC infusion, 5 were chosen for analysis (%TBSA 40 ± 15; age 51 ± 18). All data were pooled with 11 comparisons both during and after hdVC. The mean POCG (225 ± 71) was significantly higher than mean LG (138 ± 41) on hdVC (P = .002). There was no difference between POCG (138 ± 30) and LG (128 ± 23) after hdVC was finished (P = .09). There was a negative correlation between POCG and LG on hdVC (-0.64, P = .04) and a positive correlation off hdVC (0.89, P = .0005). POCG analysis during hdVC infusion is significantly higher than laboratory glucose measurements. Once the hdVC infusion is complete, POCG and laboratory glucose measurements are not statistically different. Treating erroneously high glucose based on POC testing is potentially dangerous and could lead to hypoglycemia and seizures. PMID:25162951

Kahn, Steven A; Lentz, Christopher W

2015-01-01

173

An accurate spectroscopic calibration for non-invasive glucose monitoring by modeling the physiological glucose dynamics  

OpenAIRE

The physiological lag between blood and interstitial fluid (ISF) glucose is a major challenge for non-invasive glucose concentration measurements. This is a particular problem for spectroscopic techniques, which predominantly probe ISF glucose, creating inconsistencies in calibration, where blood glucose measurements are used as reference. To overcome this problem, we present a dynamic concentration correction (DCC) scheme, based on the mass transfer of glucose between blood and ISF, to ensur...

Barman, Ishan; Kong, Chae-ryon; Singh, Gajendra P.; Dasari, Ramachandra R.; Feld, Michael S.

2010-01-01

174

Synthesis and anticancer activity of new flavonoid analogs and inconsistencies in assays related to proliferation and viability measurements  

OpenAIRE

Flavonoids have been studied intensely for their ability to act as anti-carcinogenic, anti-inflammatory, anti-viral and anti-aging agents and are often marketed as supplements related to their anti-inflammatory activity. Previous studies have primarily focused on the effects of polar natural flavonoids. We examined the activity of novel hydrophobic and lipophilic flavonols against human DU-145 and PC-3 prostate cancer cell lines. All flavonol analogs were more active than the naturally occurr...

Forbes, Alaina M.; Lin, Huimin; Meadows, Gary G.; Meier, G. Patrick

2014-01-01

175

A novel method based solely on FPGA units enabling measurement of time and charge of analog signals in Positron Emission Tomography  

CERN Document Server

This article presents a novel technique for precise measurement of time and charge based solely on FPGA (Field Programmable Gate Array) device and few satellite discrete electronic components used in Positron Emission Tomography (PET). Described approach simplifies electronic circuits, reduces the power consumption, lowers costs, merges front-end electronics with digital electronics and also makes more compact final design. Furthermore, it allows to measure time when analog signals cross a reference voltage at different threshold levels with a very high precision of $\\sim$ 10ps (rms) and thus enables sampling of signals in a voltage domain.

Pa?ka, M; Bia?as, P; Czerwi?ski, E; Kap?on, ?; Kochanowski, A; Korcyl, G; Kowal, J; Kowalski, P; Kozik, T; Krzemie?, W; Molenda, M; Moskal, P; Nied?wiecki, Sz; Pawlik, M; Raczy?ski, L; Rudy, Z; Salabura, P; Sharma, N G; Silarski, M; S?omski, A; Smyrski, J; Strzelecki, A; Wi?licki, W; Zieli?ski, M; Zo?, N

2013-01-01

176

Measurement of muscle and whole body (WB) glucose metabolism (GM) in vivo by combined stable isotope (SI) and PET techniques - Validation in an animal model  

International Nuclear Information System (INIS)

Aim/Background: Primed-constant infusion of SI labeled tracers is a classic technique for studying metabolism at the WB level, however, without invasive A-V difference data it provides no information about the metabolism of specific tissues. In contrast PET provides primarily tissue specific data. The aim of this study is to apply PET in combination with SI methods in an animal to simultaneously quantify substrate metabolism in specific tissues and the WB. Methods and materials: Animals: Seven white New Zealand rabbits (Mean ± SE 3.7 ± 0.1 kg;) were studied. After 14 hours of fast, they were surgically prepared by tracheotomy and implantation of catheters into carotid artery (Ca), jugular vein (Jv), and right femoral vein (Fv) under anesthesia. PET Imaging: The animal was placed in supine position in the gantry of a PC-4096 PET camera. Transmission images (5 min.) with a rotating pin source containing fib 68Ge were acquired with the central tomographic slice positioned to include both hind limbs (HLs). Each animal received C15O2 inhalation and was imaged for blood flow (BE) rate in HL muscles. Then, 18FDG (? 8 mCi) was injected into the animal through jugular vein, followed by serial PET images of muscle glucose metabolism (GM) for 90 min. Primed constant infusion of [6,6, 2H]-glucose (0.8?mol/kg/min, priming 64umol/kg) was conducted simultaneously. Plateau level blood samples were taken from the Cl blood samples were taken from the Ca and Fv for WB and HL GM. Stable Isotope Measurements: The whole body glucose metabolic rate and the plasma glucose kinetics are calculated according to the conventional stable isotope steady state kinetics model. Q=i(E,/EP-l) where i is the infusion rate of stable isotope labeled [6,6, 2H2]-glucose, E1 and EP are the isotopic enrichments of [6,6, 2H2]-glucose in infusate and plasma under steady state conditions. The hind limb glucose metabolism was also measured using stable isotope tracer and tracee difference across the hind limb. WB GM determined by SI was 2.54 ± 0.22 mg/kg/min and GM in the right HL measured by A-V difference of ST was 0.77 ± 0.12 mg/leg/min. Based on muscle mass in HL (199 ± 7.8 g), LM GM (?g/g tissue/min) was calculated to be 3.40 ± 0.46 by St and 3.64 ± 0.22 by PET (N.S; paired t-test). BF to HL muscle determined by C15O2 inhalation was 0.059 ± 0.01 ml/g tissue/min. Discussion: The two in vivo methods provided comparable quantitative information on muscle protein metabolism. PET measurements have the advantage of less invasive than A-V difference methods using SI, but it does not provide the information on whole body glucose disposal rate. Therefore combined SI and PET would provide more complete picture of whole body and regional glucose metabolism in vivo. Conclusions: PET-ST is a non-invasive approach to simultaneously quantify WB and muscle GM without biopsy, hence a powerful tool for human studies under various physio-pathophysiological conditions. (author)

177

Affinity of glucose transport in Saccharomyces cerevisiae is modulated during growth on glucose.  

OpenAIRE

By using a modified technique to measure glucose uptake in Saccharomyces cerevisiae, potential uncertainties have been identified in previous determinations. These previous determinations had led to the proposal that S. cerevisiae contained a constitutive low-affinity glucose transporter and a glucose-repressible high-affinity transporter. We show that, upon transition from glucose-repressed to -derepressed conditions, the maximum rate of glucose transport is constant and only the affinity fo...

Walsh, M. C.; Smits, H. P.; Scholte, M. E.; Dam, K.

1994-01-01

178

In vivo measurements of whole body (WB) and skeletal muscle glucose metabolism under basal and euglycemic insulin clamp (Clamp) by combined PET and stable isotope (SI) tracer studies  

International Nuclear Information System (INIS)

Aim/Background: Primed-constant infusion of SI labeled tracers is a classic technique for studying metabolism at the WB level, however, this procedure provides no information about the metabolism of specific tissues. In contrast PET provides primarily tissue specific data. In this study, we combined PET with SI techniques to measure glucose metabolism in WB and lower limb skeletal muscle (LLM) of humans under Basal and Clamp conditions. Methods and Materials: Four healthy volunteers (73.0 ± 6.0 kg, mean ± sem) were studied. After fasting overnight, each subject was injected with 10 mCi of 18FDG and serial 1.0 min. PET images of the mid-thigh region were acquired over 90 min. Arterial blood samples were collected in parallel. Glucose metabolic rate (GM) was calculated with a 3-compartment / 4 rate constant model; LC assumed to be 1.0. A primed constant infusion of [6,6, 2H2]glucose was performed in parallel with the PET measurements. On another day, the PET and SI measurements were repeated under clamp conditions. All results are expressed as mean ± sem. Results: The glucose kinetics in whole body and in low limb skeletal muscles are shown. Under in vivo conditions, Clamp caused: 1) a 10.2 ± 2.3 fold increase in GM by LLM but only a 4.7 ± 0.4 fold increase in GM by MB. 2) Increased contribution of LLM to WB GM, indicating that LLM GM is more sensitive to insulin compared with anterior LLM (extensors). Discussion: The study demonstrsors). Discussion: The study demonstrated the unique advantages of using PET to study substrate metabolism in specific tissues in human subjects: i) It is less invasive than the conventional A-V difference and muscle biopsy method. ii) It provides a more detailed picture of substrate metabolism in different parts of the muscle in the same limb, as compared to one spot muscle biopsy. Data in demonstrated that GM in posterior LLM is more sensitive to insulin than that in anterior LLM. iii) It can detect substrate metabolism in deep muscles which cannot be reached by biopsy technique. Therefore PET combined with stable isotope tracer can non-invasively provide a more complete in vivo picture of glucose metabolism in WB and in different parts of the skeletal muscles in human subjects. Conclusions: 1. Euglycemic insulin clamp (EGIC) caused a significant suppress of endogenous glucose production, either released from glycogenolysis or gluconeogenesis in the fasting condition. 2. Glucose metabolism in LLM is more sensitively regulated by insulin than other tissues. 3. On the same lower limb, glucose metabolism posterior muscle group is more sensitively regulated by insulin than those in the anterior. (author)

179

High-speed measurement of AC-biased front-end circuit for a superconducting analog-to-digital converter  

International Nuclear Information System (INIS)

We demonstrated high-speed data transmission from a superconducting front-end circuit to a semiconductor back-end circuit for an analog-to-digital converter. In this study, the front-end circuit consisted of a 1-4 demultiplexer and four-channel stacked-type amplifiers. The back-end circuit consisted of low noise amplifiers and decision circuits. In the front-end circuit, data distribution at a frequency of 10 GHz and amplification of four-channel data signals at 2.5 GHz were performed and an output voltage of 4.2 mV was obtained. In the back-end circuit, data decision at 2.5 GHz was successfully performed at an error rate below 10-6. These results enable us to operate the whole A/D converter at sampling frequency of 10 GHz and evaluate its performance, including the bit accuracy

180

The dipeptidyl peptidase-4 inhibitor linagliptin lowers postprandial glucose and improves measures of ?-cell function in type 2 diabetes.  

Science.gov (United States)

Progressive deterioration of pancreatic ?-cell function in patients with type 2 diabetes mellitus (T2DM) contributes to worsening of hyperglycaemia. To investigate the effects of the dipeptidyl peptidase-4 inhibitor linagliptin on ?-cell function parameters, a pooled analysis of six randomized, 24-week, placebo-controlled, phase 3 trials of 5 mg of linagliptin daily was performed in 2701 patients with T2DM (linagliptin, n = 1905; placebo, n = 796). At week 24, observed improvements in HbA1c, fasting plasma glucose, and 2-h postprandial glucose were significantly greater for linagliptin than placebo (all p linagliptin, and did not change with placebo (placebo-adjusted mean ± s.e. change for linagliptin: 16.5 ± 4.6 (mU/l)/(mmol/l); p = 0.0003). Further study is required to determine if the significant improvement in HOMA-%? with linagliptin will translate into long-term improvements in ?-cell function. PMID:24821586

Heise, T; Larbig, M; Patel, S; Seck, T; Hehnke, U; Woerle, H-J; Dugi, K

2014-10-01

181

Precision of glucose measurements in control sera by isotope dilution/mass spectrometry: proposed definitive method compared with a reference method  

International Nuclear Information System (INIS)

This improved isotope-dilution gas chromatographic/mass spectrometric (GC/MS) method, in which [13C]glucose is the internal standard, meets the requirements of a Definitive Method. In a first study with five reconstituted lyophilized sera, a nested analysis of variance of GC/MS values indicated considerable among-vial variation. The CV for 32 measurements per serum ranged from 0.5 to 0.9%. However, concentration and uncertainty values (mmol/L per gram of serum) assigned to one serum by the NBS Definitive Method (7.56 +/- 0.28) were practically identical to those obtained with the proposed method (7.57 +/- 0.20). In the second study, we used twice more [13C]glucose diluent to assay four serum pools and two lyophilized sera. The CV ranged from 0.26 to 0.5% for the serum pools and from 0.28 to 0.59% for the lyophilized sera. In comparison, results by the hexokinase/glucose-6-phosphate dehydrogenase reference method agreed within acceptable limits with those by the Definitive Method but tended to be slightly higher (up to 3%) for lyophilized serum samples or slightly lower (up to 2.5%) for serum pools

182

Stimulus processing of glycine is dissociable from that of sucrose and glucose based on behaviorally measured taste signal detection in Sac 'taster' and 'non-taster' mice.  

Science.gov (United States)

Mouse strains have been divided into 'tasters' and 'non-tasters' based on their relatively high and low preference, respectively, for low concentrations of sucrose and saccharin. These phenotypic differences appear to be due to a polymorphism in the gene at the Sac locus encoding for the T1R3 taste receptor selectively affecting the functionality of the T1R2+3 heterodimer. To psychophysically examine whether these phenotypes are due to sensory sensitivity as opposed to hedonic responsiveness, we measured taste signal detection of sucrose, glucose, and glycine by Sac taster (C57BL/6J and SWR/J) and non-taster (129P3/J and DBA/2J) strains in an operant conditioning paradigm using a gustometer. The taster mice had lower detection thresholds for sucrose and glucose compared with the non-taster mice. The detection thresholds corresponded well with reported responsiveness to low concentrations of these sugars in two-bottle intake tests suggesting that the Sac taster phenotype has a sensory basis and is not simply a matter of strain differences in the hedonic evaluation of weak intensities of the stimuli. Taster status did not entirely account for the strain differences in detection thresholds for glycine, a 'sweet' tasting amino acid. Collapsed across strains, detection thresholds for sucrose and glucose were highly correlated with each other (r = 0.81), but only modestly correlated with those for glycine (r < or = 0.43). This suggests that stimulus processing of glycine in the perithreshold intensity domain can be dissociated from that of sucrose and glucose. The mechanism underlying this difference may be related to the ability of glycine to bind with the T1R1+3 heterodimer. PMID:15337688

Eylam, Shachar; Spector, Alan C

2004-09-01

183

Isolation of a Mutant of Kluyveromyces marxianus Resistant to Glucose Repression  

OpenAIRE

In this study, we isolated a mutant of Kluyveromyces marxianus resistance to glucose repression. To screen for depression mutants, the strains were treated with UV rays. Fifteen resistant mutant strains were isolated. The mutants were further screened for glucose-repression-resistant mutants in the presence of 2-deoxy-D-glucose, an analog to glucose and lactose as the sole carbon source. In this condition, one glucose-repression-resistant mutant was isolated. The enzyme activity in this mutan...

Moeini Hassan; Vallian Sadeq; Nahvi Iraj; Behzadipour Niloofur

2006-01-01

184

Evaluation of the relationship between capillary and venous plasma glucose concentrations obtained by the HemoCue Glucose 201+ system during an oral glucose tolerance test  

OpenAIRE

Abstract In 55 women with previous gestational diabetes mellitus, simultaneous capillary and venous plasma glucose concentrations were measured at 0, 30 and 120 min during a 75 g oral glucose tolerance test (OGTT). The aims of the study were to examine the relationship between capillary and venous glucose measurements, and to establish equations for the conversion of capillary and venous glucose concentrations using the HemoCue Glucose 201+ system. Additionally, the correlation between the ca...

Ignell, Claes; Berntorp, Kerstin

2011-01-01

185

A sensitive LC-MS/MS method for measurement of organophosphorus pesticides and their oxygen analogs in air sampling matrices.  

Science.gov (United States)

A rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for determination of levels of the organophosphorus (OP) pesticides chlorpyrifos (CPF), azinphos methyl (AZM), and their oxygen analogs chlorpyrifos-oxon (CPF-O) and azinphos methyl-oxon (AZM-O) on common active air sampling matrices. XAD-2 resin and polyurethane foam (PUF) matrices were extracted with acetonitrile containing stable-isotope labeled internal standards (ISTD). Analysis was accomplished in Multiple Reaction Monitoring (MRM) mode, and analytes in unknown samples were identified by retention time (±0.1 min) and qualifier ratio (±30% absolute) as compared to the mean of calibrants. For all compounds, calibration linearity correlation coefficients were ?0.996. Limits of detection (LOD) ranged from 0.15-1.1 ng/sample for CPF, CPF-O, AZM, and AZM-O on active sampling matrices. Spiked fortification recoveries were 78-113% from XAD-2 active air sampling tubes and 71-108% from PUF active air sampling tubes. Storage stability tests also yielded recoveries ranging from 74-94% after time periods ranging from 2-10 months. The results demonstrate that LC-MS/MS is a sensitive method for determining these compounds from two different matrices at the low concentrations that can result from spray drift and long range transport in non-target areas following agricultural applications. In an inter-laboratory comparison, the limit of quantification (LOQ) for LC-MS/MS was 100 times lower than a typical gas chromatography-mass spectrometry (GC-MS) method. PMID:24328542

Armstrong, Jenna L; Dills, Russell L; Yu, Jianbo; Yost, Michael G; Fenske, Richard A

2014-01-01

186

Analog elements for transuranic chemistries  

International Nuclear Information System (INIS)

The analytical technique for measuring trace concentrations of the analog rare earth elements has been refined for optimal detection. The technique has been used to determine the rare earth concentrations in a series of geological and biological materials, including samples harvested from controlled lysimeter investigations. These studies have demonstrated that any of the trivalent rare earth elements may be used as analog elements for the trivalent transuranics, americium and curium

187

Glucose and fructose 6-phosphate cycle in humans  

International Nuclear Information System (INIS)

We have determined the rate of glucose cycling by comparing turnovers of [2-3H]- and [6-3H]glucose under basal conditions and during a glucose infusion. Moreover, the activity of the fructose 6-phosphate cycle was assessed by comparing [3-3H]- and [6-3H]glucose. The study included eight lean subjects with normal glucose tolerance. They participated in two randomly performed investigations. In one experiment [2-3H]- and [6-3H]glucose were given simultaneously, while in the other only [3-3H]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 [6-3H]glucose rather than [3-3H]glucose when measuring glucose production and particularly when assessing glucose cycle

188

Regulation of the glucose:H+ symporter by metabolite-activated ATP-dependent phosphorylation of HPr in Lactobacillus brevis.  

OpenAIRE

Lactobacillus brevis takes up glucose and the nonmetabolizable glucose analog 2-deoxyglucose (2DG), as well as lactose and the nonmetabolizable lactose analoge thiomethyl beta-galactoside (TMG), via proton symport. Our earlier studies showed that TMG, previously accumulated in L. brevis cells via the lactose:H+ symporter, rapidly effluxes from L. brevis cells or vesicles upon addition of glucose and that glucose inhibits further accumulation of TMG. This regulation was shown to be mediated by...

Ye, J. J.; Neal, J. W.; Cui, X.; Reizer, J.; Saier, M. H.

1994-01-01

189

Estimating Plasma Glucose from Interstitial Glucose: The Issue of Calibration Algorithms in Commercial Continuous Glucose Monitoring Devices  

Directory of Open Access Journals (Sweden)

Full Text Available Evaluation of metabolic control of diabetic people has been classically performed measuring glucose concentrations in blood samples. Due to the potential improvement it offers in diabetes care, continuous glucose monitoring (CGM in the subcutaneous tissue is gaining popularity among both patients and physicians. However, devices for CGM measure glucose concentration in compartments other than blood, usually the interstitial space. This means that CGM need calibration against blood glucose values, and the accuracy of the estimation of blood glucose will also depend on the calibration algorithm. The complexity of the relationship between glucose dynamics in blood and the interstitial space, contrasts with the simplistic approach of calibration algorithms currently implemented in commercial CGM devices, translating in suboptimal accuracy. The present review will analyze the issue of calibration algorithms for CGM, focusing exclusively on the commercially available glucose sensors.

Paolo Rossetti

2010-12-01

190

Highly sensitive measurement of ?-rays in NaI(Tl) scintillator by pulse shape discrimination with charge-sensitive analog-to-digital converter  

International Nuclear Information System (INIS)

In order to investigate the contamination due to the radioactive isotopes (RIs) in NaI(Tl) scintillator for dark matter search, a simple method of pulse shape discrimination (PSD) to extract ?-rays energy spectrum was developed. Two linear signals of different timings were input into a single module charge-sensitive analog-to-digital converter. The ?- and the ?-rays were discriminated by comparing the total charge integration of a pulse with the partial one. As a result, the ?-rays energy spectrum with NaI(Tl) was successfully and clearly extracted. The present work showed that the PSD method was performed by the minimum electronic circuits. The sensitivity was high enough to measure RIs of a few ?Bq/kg in high pure NaI crystals for dark matter search

191

A new analog detection system with target-imaging capability for ?SR measurements in a pulsed muon beam  

International Nuclear Information System (INIS)

We have developed a new method to measure ?SR time spectra macroscopically in a high-intensity pulsed muon beam. Each macroscopic pulse from the Cherenkov radiation induced by decay positrons from stopped muons in a burst is measured by using a fast transient digitizer. This rate-unlimited method is effective in avoiding the distortion of the initial part of time spectra. The present counter system using Freon-12 at normal pressure is characterized by its target imaging capability and suitable threshold for muon-decay electrons (Ee > 10 MeV). We describe its principle, performance and data analyses. (orig.)

192

Unlocking the Potential of Continuous Glucose Monitoring: A New Guideline Supports the Development of Continuous Glucose Monitoring Devices  

OpenAIRE

Continuous glucose monitoring (CGM) is a new technology that allows patients to measure glucose levels continuously over several days. It has several advantages over traditional glucose meters in that it does not involve repeated finger sticks and can measure trends and track changes in glucose levels over time. The Clinical and Laboratory Standards Institute, working with the Diabetes Technology Society, published Performance Metrics for Continuous Interstitial Glucose Monitoring; Approved G...

D Archangelo, Melissa J.

2009-01-01

193

Strategies for built-in characterization testing and performance monitoring of analog RF circuits with temperature measurements  

International Nuclear Information System (INIS)

This paper presents two approaches to characterize RF circuits with built-in differential temperature measurements, namely the homodyne and heterodyne methods. Both non-invasive methods are analyzed theoretically and discussed with regard to the respective trade-offs associated with practical off-chip methodologies as well as on-chip measurement scenarios. Strategies are defined to extract the center frequency and 1 dB compression point of a narrow-band LNA operating around 1 GHz. The proposed techniques are experimentally demonstrated using a compact and efficient on-chip temperature sensor for built-in test purposes that has a power consumption of 15 µW and a layout area of 0.005 mm2 in a 0.25 µm CMOS technology. Validating results from off-chip interferometer-based temperature measurements and conventional electrical characterization results are compared with the on-chip measurements, showing the capability of the techniques to estimate the center frequency and 1 dB compression point of the LNA with errors of approximately 6% and 0.5 dB, respectively

194

CSF glucose test  

Science.gov (United States)

Glucose test - CSF; Cerebrospinal fluid glucose test ... The glucose level in the CSF should be 50 - 80 mg/100 mL (or greater than 2/3 of the blood sugar level). Note: Normal value ranges may vary slightly ...

195

Blood Glucose Log  

Science.gov (United States)

... here ¢ cut here ¢ If you have high blood glucose , make notes in your log and talk with ... physical activity, or diabetes medicines. Having low blood glucose means that your blood glucose level is too ...

196

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available www.diabetes.org > Living With Diabetes > Treatment and Care > Blood Glucose Testing Share: Print Page Text Size: ... In this section Living With Diabetes Treatment and Care Blood Glucose Testing Checking Your Blood Glucose A1C ...

197

Continuous Glucose Monitoring  

Science.gov (United States)

... try to achieve better glucose control. How does CGM work? There are two types of CGM devices. ... the trends in their glucose levels. How does CGM compare with standard blood glucose tests? Studies show ...

198

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 ... glucose) Dawn Phenomenon Checking for Ketones Tight Diabetes Control donate en -- Put a Stop to Diabetes. - 2015- ...

199

CMOS image sensor-based implantable glucose sensor using glucose-responsive fluorescent hydrogel  

OpenAIRE

A CMOS image sensor-based implantable glucose sensor based on an optical-sensing scheme is proposed and experimentally verified. A glucose-responsive fluorescent hydrogel is used as the mediator in the measurement scheme. The wired implantable glucose sensor was realized by integrating a CMOS image sensor, hydrogel, UV light emitting diodes, and an optical filter on a flexible polyimide substrate. Feasibility of the glucose sensor was verified by both in vitro and in vivo experiments.

Tokuda, Takashi; Takahashi, Masayuki; Uejima, Kazuhiro; Masuda, Keita; Kawamura, Toshikazu; Ohta, Yasumi; Motoyama, Mayumi; Noda, Toshihiko; Sasagawa, Kiyotaka; Okitsu, Teru; Takeuchi, Shoji; Ohta, Jun

2014-01-01

200

CMOS image sensor-based implantable glucose sensor using glucose-responsive fluorescent hydrogel.  

Science.gov (United States)

A CMOS image sensor-based implantable glucose sensor based on an optical-sensing scheme is proposed and experimentally verified. A glucose-responsive fluorescent hydrogel is used as the mediator in the measurement scheme. The wired implantable glucose sensor was realized by integrating a CMOS image sensor, hydrogel, UV light emitting diodes, and an optical filter on a flexible polyimide substrate. Feasibility of the glucose sensor was verified by both in vitro and in vivo experiments. PMID:25426316

Tokuda, Takashi; Takahashi, Masayuki; Uejima, Kazuhiro; Masuda, Keita; Kawamura, Toshikazu; Ohta, Yasumi; Motoyama, Mayumi; Noda, Toshihiko; Sasagawa, Kiyotaka; Okitsu, Teru; Takeuchi, Shoji; Ohta, Jun

2014-11-01

201

Carbon Dioxide Monitoring, Verification and Accounting (MVA) by Carbon Stable Isotope Measurements at Artificial and Natural Analog Sites  

Science.gov (United States)

Storage of carbon dioxide (CO2) in geologic formations is one method to mitigate greenhouse gas emissions from fossil fuel combustion. Monitoring, verification and accounting (MVA) of geologically sequestered CO2 is critical to the operation of a geologic storage site. Surface MVA techniques capable of identifying seepage from the sequestration reservoir at or below ambient CO2 concentrations are desired. The CO2 carbon stable isotope ratio (?13CO2) is a sensitive diagnostic signature that can distinguish between anthropogenic (?13CO2proportional to the species concentration. This FMS signature is recorded at multiple wavelengths to obtain the CO2 carbon isotope ratio. Two instruments using the FMS technique have been built and tested at LANL. The first instrument is an in situ instrument that draws ambient air into a multi-pass cell for a point source measurement. The second instrument uses an open-air path, tested up to 160 m round trip, to measure the column average CO2 carbon isotopic ratio. In this paper, results from laboratory tests and field deployments will be presented. The Zero Emissions Research & Technology (ZERT) group at Montana State University established a field test site where 0.15 - 0.20 tons of CO2 per day were released approximately 2 m below the soil surface to test the performance of CO2 detection instruments and measurement techniques. The in situ instrument was also deployed to the Valles Caldera National Preserve in the Jemez Mountains of New Mexico where CO2 is trapped at night which results in large concentration swings. Finally, the instruments were deployed to the Juniper-Pinion field site at Los Alamos National Laboratory.

Clegg, S. M.; Humphries, S. D.; McInroy, R. E.; Rahn, T.; Fessenden, J. E.; Dobeck, L.; Barr, J. L.; Spangler, L.

2011-12-01

202

Biological evaluation of two iodine-123-labeled D-glucose acetals prepared as glucose transporter radioligands  

International Nuclear Information System (INIS)

Two iodinated acetals of D-glucose, 4,6-(R)-O-(2'-iodoethylidene)-?, ?-D-glucose and 4,6-(R)-O-(4'-iodobenzylidene)-?, ?-D-glucose , were prepared and their potential as suitable SPECT radioligands for imaging of glucose transporters was studied. Both are analogs of acetal D-glucose derivatives, which are known to bind to the exofacial sites of the glucose transport protein (GluT). To assess whether iodinated acetals 1 and 2 interacted with the glucose transporter, they were tested in vitro in human erythrocytes (GluT1) and neonatal rat cardiomyocytes (GluT4). The results indicated that 1 and 2 had a very low affinity for the glucose transporter and probably accumulated in cells. Study of their tissue distribution was carried out in the mouse in vivo: Both compounds showed fast tissue clearance with preferential renal elimination. It is concluded that iodinated acetals of D-glucose 1 and 2 are not suitable for GluT targeting in vivo

203

The determination of solubility and diffusion coefficient for solids in liquids by an inverse measurement technique using cylinders of amorphous glucose as a model compound  

International Nuclear Information System (INIS)

The importance of sugar and sugar-containing materials is well recognized nowadays, owing to their application in industrial processes, particularly in the food, pharmaceutical and cosmetic industries. Because of the large numbers of those compounds involved and the relatively small number of solubility and/or diffusion coefficient data for each compound available, it is highly desirable to measure the solubility and/or diffusion coefficient as efficiently as possible and to be able to improve the accuracy of the methods used. In this work, a new technique was developed for the measurement of the diffusion coefficient of a stationary solid solute in a stagnant solvent which simultaneously measures solubility based on an inverse measurement problem algorithm with the real-time dissolved amount profile as a function of time. This study differs from established techniques in both the experimental method and the data analysis. The experimental method was developed in which the dissolved amount of solid solute in quiescent solvent was investigated using a continuous weighing technique. In the data analysis, the hybrid genetic algorithm is used to minimize an objective function containing a calculated and a measured dissolved amount with time. This is measured on a cylindrical sample of amorphous glucose in methanol or ethanol. The calculated dissolved amount, that is a function of the unknown physical properties of the solid solute in the solvent, is calculated by the solution of the two-dimensional nonlinear inverse natural convection problem. The estimated values of the solubility of amorphous glucose in methanol and ethanol at 293 K were respectively 32.1 g/100 g methanol and 1.48 g/100 g ethanol, in agreement with the literature values, and support the validity of the simultaneously measured diffusion coefficient. These results show the efficiency and the stability of the developed technique to simultaneously estimate the solubility and diffusion coefficient. Also the influence of the solution density change and the initial concentration conditions on the dissolved amount was investigated by the numerical results using the estimated parameters. It is found that the theoretical assumption to simplify the inverse measurement problem algorithm is reasonable for low solubility

204

Assessing liver function by magnetic resonance imaging two-dimensional phase-shift flow measurement of portal venous blood flow after oral intake of glucose  

Energy Technology Data Exchange (ETDEWEB)

We have already reported that the ratio of portal venous flow 30 min after oral intake of glucose 75 g to that before intake (PVFR30), measured using pulsed-Doppler ultrasonography (US), correlated significantly with other indicators of liver function and that it could be used to estimate hepatic function before surgery, including liver resection. In this study, to assess the disadvantages of pulsed-Doppler ultrasonography, PVFR30 was measured using two-dimensional (2D) phase-shift (PS) magnetic resonance imaging (MRI). PVFR30 was measured in 17 patients and 7 volunteers: 13 with liver cirrhosis (LC) and 11 without LC (non-LC). Portal venous flow could be measured in all patients without any disturbance of intestinal gas or patient fat, or the high degree of technical skill that Doppler US requires. PVFR30 was significantly lower in the LC group than in the non-LC group. In addition, it correlated significantly with other indicators of liver function, including the indocyanine green clearance test, prothrombin time, hepaplastin test, and cholinesterase activity. These results suggest that PVFR30 measured by 2D PS MRI can be used to estimate liver function, and that this MRI method can be performed more easily than pulsed-Doppler US. (author)

Yagi, Hidefumi; Sakamoto, Michio [Tomogikukai Showa Hospital, Fukuoka (Japan); Midorikawa, Takemasa [Showa Univ., Yokohama (Japan). Fujigaoka Hospital] [and others

2002-05-01

205

Parsing glucose entry into the brain: novel findings obtained with enzyme-based glucose biosensors.  

Science.gov (United States)

Extracellular levels of glucose in brain tissue reflect dynamic balance between its gradient-dependent entry from arterial blood and its use for cellular metabolism. In this work, we present several sets of previously published and unpublished data obtained by using enzyme-based glucose biosensors coupled with constant-potential high-speed amperometry in freely moving rats. First, we consider basic methodological issues related to the reliability of electrochemical measurements of extracellular glucose levels in rats under physiologically relevant conditions. Second, we present data on glucose responses induced in the nucleus accumbens (NAc) by salient environmental stimuli and discuss the relationships between local neuronal activation and rapid glucose entry into brain tissue. Third, by presenting data on changes in NAc glucose induced by intravenous and intragastric glucose delivery, we discuss other mechanisms of glucose entry into the extracellular domain following changes in glucose blood concentrations. Lastly, by showing the pattern of NAc glucose fluctuations during glucose-drinking behavior, we discuss the relationships between "active" and "passive" glucose entry to the brain, its connection to behavior-related metabolic activation, and the possible functional significance of these changes in behavioral regulation. These data provide solid experimental support for the "neuronal" hypothesis of neurovascular coupling, which postulates the critical role of neuronal activity in rapid regulation of vascular tone, local blood flow, and entry of glucose and oxygen to brain tissue to maintain active cellular metabolism. PMID:25490002

Kiyatkin, Eugene A; Wakabayashi, Ken T

2015-01-21

206

The analog readout of the LHCb vertex detector and study of the measurement of the B$_s$ oscillation frequency  

CERN Document Server

The LHCb detector is one of the four experimental setups built to detect high-energy proton collisions to be produced by the Large Hadron Collider (LHC). Located at CERN (Geneva, Switzerland), the LHC machine and the LHCb experiment are expected to start in 2008, and will then operate for several years. Being the largest collider of its kind, the LHC will open the way to new investigations, in the very-high energies, but also in terms of statistics for the study of rare-phenomena and flavor physics. In this framework LHCb is dedicated to precise measurements of CP-violating and rare decays of beauty hadrons, in order to test (or over-constrain) the Standard Model of particle physics. From the hardware point of view, the construction of such detectors represents several challenges; one of them is the routing at a very high frequency of many signals in a harsh radiation environment. We designed to this purpose a hardware setup and a software filter which together reduce the cross-talk present in the readout of ...

Borel, J

2008-01-01

207

Application of tracer kinetic principles to the measurement of local rates of cerebral glucose metabolism, blood flow and protein synthesis with PCT: normal values and sensory activation  

International Nuclear Information System (INIS)

Some of the different ways in which the principles of tracer kinetics are used with positron computed tomography (PCT) for analytical estimates of biochemical reaction rates and blood flow, are illustrated. This allows examination of nutrient delivery by local cerebral blood flow (LCBF) metabolic function by local cerebral metabolic rate for glucose (LCMRGlc), and degeneration, regeneration or reorganization structurally with protein synthesis. This combined with existing techniques for measuring local cerebral blood volume with C-11 CO, facilitated membrane transport with C-11 O-methylglucose, oxygen extraction and utilization with O-15 O2, along with other techniques under development for amino acid metabolism and assay of receptors provide an increasing number of probes for examining biochemical basis of both normal and abnormal function of the human brain with tracer kinetic techniques and positron computed tomography

208

Insulin regulation of renal glucose metabolism in conscious dogs.  

OpenAIRE

Previous studies indicating that postabsorptive renal glucose production is negligible used the net balance technique, which cannot partition simultaneous renal glucose production and glucose uptake. 10 d after surgical placement of sampling catheters in the left renal vein and femoral artery and a nonobstructive infusion catheter in the left renal artery of dogs, systemic and renal glucose and glycerol kinetics were measured with peripheral infusions of [3-3H]glucose and [2-14C]glycerol. Aft...

Cersosimo, E.; Judd, R. L.; Miles, J. M.

1994-01-01

209

Glucose kinetics in infants of diabetic mothers  

International Nuclear Information System (INIS)

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

210

Transporter-mediated absorption is the primary route of entry and is required for passive absorption of intestinal glucose into the blood of conscious dogs.  

Science.gov (United States)

To determine the contributions of transporter-mediated and passive absorption during an intraduodenal glucose infusion in a large animal model, six mongrel dogs had sampling catheters (portal vein, femoral artery, duodenum), infusion catheters (vena cava, duodenum) and a portal vein flow probe implanted 17 d before an experiment. Protocols consisted of a basal (-30 to 0 min) and an experimental (0-90 min) period. An intraduodenal glucose infusion of 44 micromol/(kg. min) was initiated at t = 0 min. At t = 20 and 80 min, 3-O-[3H]methylglucose and L-[14C]glucose (L-Glc) were injected intraduodenally. Phloridzin, an inhibitor of the Na+/K+ ATP-dependent transporter (SGLT1), was infused from t = 60 to 90 min in the presence of a peripheral isoglycemic clamp. Net gut glucose output was 21.1 +/- 3.0 micromol/(kg. min) from t = 0 to 60 min. Transporter-mediated glucose absorption was calculated using three approaches, which involved either direct measurements or indirect estimates of duodenal glucose analog radioactivities, to account for the assumptions and difficulties inherent to duodenal sampling. Values were essentially the same regardless of calculations used because transporter-mediated absorption was 89 +/- 1%, 90 +/- 2% and 91 +/- 2% of net gut glucose output. Phloridzin-induced inhibition of transporter-mediated absorption completely abolished passive absorption of L-Glc. We conclude that in dogs, transporter-mediated glucose absorption constitutes the vast majority of glucose absorbed from the gut and is required for passive glucose absorption. The method described here is applicable to investigation of the mechanisms of gut glucose absorption under a variety of nutritional, physiologic and pathophysiologic conditions. PMID:12097672

Pencek, R Richard; Koyama, Yoshiharu; Lacy, D Brooks; James, Freyja D; Fueger, Patrick T; Jabbour, Kareem; Williams, Phillip E; Wasserman, David H

2002-07-01

211

Analogous: Digital / Analogue Metaphors.  

OpenAIRE

When discussing our understanding of the world, the term ‘analogue’ has become shorthand for anything not digital, and has become an analogy of its own. ‘Digital’ has also become an analogy for anything requiring a computer. This essay starts to investigate some of the analogies of analogue and digital media to reveal the complexity of thinking about animation.

Carpenter, Ele

2011-01-01

212

FRET-based glucose monitoring for bioprocessing  

Science.gov (United States)

The glucose-mediated conformational changes in the glucose binding protein (GBP) have been exploited in the development of fluorescence based glucose sensors. The fluorescence response is generated by a polarity sensitive dye attached to a specific site. Such fluorescent sensors respond to submicromolar glucose at diffusion-controlled rates mimicking the wild type. However, such sensors have been limited to in vitro glucose sensing because of the preliminary dye-labeling step. In the study described here, the dye-labeling step is omitted by genetically encoding the GBP with two green fluorescent mutants namely, the green fluorescent protein (GFP) and the yellow fluorescent protein (YFP) in the N- and C-terminal ends, respectively. These two GFP mutants comprise a fluorescence resonance energy transfer (FRET) donor and acceptor pair. Thus, when glucose binds with GBP, the conformational changes affect the FRET efficiency yielding a dose-dependent response. A potential application for this FRET-based glucose biosensor is online glucose sensing in bioprocessing and cell culture. This was demonstrated by the measurement of glucose consumption in yeast fermentation. Further development of this system should yield in vivo measurement of glucose in bioprocesses.

Bartolome, Amelita; Smalls-Mantey, Lauren; Lin, Debora; Rao, Govind; Tolosa, Leah

2006-02-01

213

First measurements on how pressure affects the half-life of 22Na: Comparison to theory and analog to 40K  

Science.gov (United States)

Radioactive decay plays a central role in planetary sciences as appropriate decay schemes are used to date geological and astronomical processes and radioactivity provides an important source of heat in planetary bodies, both in their early history during accretion and differentiation and also over geological times. The most important isotopes that currently heat the Earth are 40K, 232Th, 235U and 238U. As radioactive decay is a nuclear process it is considered to be insensitive to external factors such as pressure or chemical environment. This has been shown to be true for ?, ?+ and ?- processes, however, electron capture decay is dependent on the electron charge density at the nucleus of a compound, which is sensitive to the external environment. Using high-resolution Ge gamma-ray detectors to make relative measurements with 137Cs and the positron decay of 22Na, we measure how pressure affects the half-life of 22Na due to electron-capture decay. Our systematics look favorable for observing this small effect. We will compare our preliminary measurements with complementary ab-initio all-electron computations using the linearized augmented plane wave method (LAPW). Using 22Na as an analog for 40K, our results suggest that the pressure effect for 40K, combined with the opposing effects of high temperatures, will have little, discernible effect on the heat production in the deep Earth as our predicted changes are smaller than the uncertainties in the total decay constant for 40K. This work was supported in part by the Carnegie/DOE Alliance Center (CDAC), through the Stewardship Science Academic Alliances Program of the U.S. Department of Energy. The LANSCE facility is operated, and portions of this work were performed, by Los Alamos National Security, LLC, funded by the U.S. Department of Energy under Contract No. DE-AC52- 06NA25396.

Lee, K. K.; Nelson, R. O.; Rundberg, R.; Steinle-Neumann, G.

2007-12-01

214

Glucose effectiveness and insulin sensitivity measurements derived from the non-insulin-assisted minimal model and the clamp techniques are concordant  

DEFF Research Database (Denmark)

We investigated the concordance between glucose effectiveness (SG) and insulin sensitivity (SI), derived from the unmodified dynamic non-insulin-assisted intravenous glucose tolerance test (IVGTT) implemented by SG(MM) and SI(MM); simulation analysis and modelling/conversational interaction (SAAM/CONSAM) versus the eu/hyperglycaemic basal insulinaemic and the euglycaemic hyperinsulinaemic clamp (SG(CLAMP) and SI(CLAMP)).

Henriksen, Jan Erik; Alford, Frank

2010-01-01

215

Four grams of glucose  

OpenAIRE

Four grams of glucose circulates in the blood of a person weighing 70 kg. This glucose is critical for normal function in many cell types. In accordance with the importance of these 4 g of glucose, a sophisticated control system is in place to maintain blood glucose constant. Our focus has been on the mechanisms by which the flux of glucose from liver to blood and from blood to skeletal muscle is regulated. The body has a remarkable capacity to satisfy the nutritional need for glucose, while ...

Wasserman, David H.

2008-01-01

216

Evidence that humans can taste glucose polymers.  

Science.gov (United States)

The sense of taste is essential for identifying potential nutrients and poisons. Accordingly, specialized taste receptor cells are activated by food-derived chemicals. Because of its importance in the human diet, oral detection of starch, or its degradation products, would presumably be highly beneficial. Yet, it has long been assumed that simple sugars are the only class of carbohydrates that humans can taste. There is, however, considerable evidence that rodents can taste starch degradation products (i.e., glucose polymers composed of maltooligosaccharides with 3-10 glucose units and maltopolysaccharides with >10 glucose units) and that their detection is independent of the sweet taste receptor, T1R2/T1R3. The present study was designed 1) to measure individual differences in human taste perception of glucose polymers, 2) to understand individual differences in the activity of salivary ?-amylase, and 3) to investigate the role that salivary ?-amylase may play in the taste perception of glucose polymers. In the first experiment, subjects rated taste intensity of glucose, sucrose, NaCl, and glucose polymers of various chain lengths, while their noses were clamped. Saliva samples from the subjects were also collected and their salivary ?-amylase activity was assayed. Results showed that the perceived intensities of glucose, sucrose, and NaCl were significantly correlated (r = 0.75-0.85, P intensity ratings of all glucose polymers were highly correlated with one another (r = 0.69-0.82, P concentrations of glucose and maltose that were inherently present in the glucose polymer stimuli and to determine whether the amounts were within a perceptually detectable range. Results revealed that the amounts of simple sugars present in the test stimuli were trivial and were mostly at an undetectable level. These data together provide strong evidence that humans can taste glucose polymers and that the responsiveness to glucose polymers is independent of that to simple sugars. PMID:25326592

Lapis, Trina J; Penner, Michael H; Lim, Juyun

2014-11-01

217

Radiometric assays for glycerol, glucose, and glycogen  

International Nuclear Information System (INIS)

We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with [32P]ATP and glycerokinase, residual [32P]ATP is hydrolyzed by heating in acid, and free [32P]phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniy described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays

218

Does the Emotional Go/No-Go Task Really Measure Behavioral Inhibition? Convergence with Measures on a Non-Emotional Analog  

OpenAIRE

This study tested the convergence of behavioral inhibition measures across emotional and non-emotional versions of the same go/no-go task in 85 college students. The two tasks differed only in the stimuli used for trial cues (i.e., circles versus facial expressions). Moderate correlations (r = .51 to r = .56) between commission errors across the emotional and non-emotional tasks support the construct validity of behavioral inhibition. Further, parametric manipulation of preceding context had ...

Schulz, Kurt P.; Fan, Jin; Magidina, Olga; Marks, David J.; Hahn, Bella; Halperin, Jeffrey M.

2007-01-01

219

Diabetes prediction, lipid accumulation product, and adiposity measures; 6-year follow-up: Tehran lipid and glucose study  

OpenAIRE

Abstract Background The body mass index (BMI) is the most commonly used marker for evaluating obesity related risks, however, central obesity measures have been proposed to be more informative. Lipid accumulation product (LAP) is an alternative continuous index of lipid accumulation, which is computed from waist circumference (WC, cm) and triglycerides (TGs, mmol/l): (WC-65) ×TG (men) and (WC-58) ×TG (women). We sought in this study to assess if LAP can outperform BMI, waist-to-height-ratio...

Azizi Fereidoun; Hadaegh Farzad; Bozorgmanesh Mohammadreza

2010-01-01

220

Isolation of a Mutant of Kluyveromyces marxianus Resistant to Glucose Repression  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, we isolated a mutant of Kluyveromyces marxianus resistance to glucose repression. To screen for depression mutants, the strains were treated with UV rays. Fifteen resistant mutant strains were isolated. The mutants were further screened for glucose-repression-resistant mutants in the presence of 2-deoxy-D-glucose, an analog to glucose and lactose as the sole carbon source. In this condition, one glucose-repression-resistant mutant was isolated. The enzyme activity in this mutant strain and the wild type strain was compared using different mediums containing 4% of each lactose and glucose and 2% glucose+2% lactose. The results demonstrated significant decreasing in glucose repression in the mutant strain as compared to the wild type. This mutant was unable to grow anaerobically on glucose in present of antimycin A, the property of rag1 mutants. This mutant is, therefore, capable of constitutive expression of ?-galactosidase, which makes it suitable for industrial purposes.

Moeini Hassan

2006-01-01

221

Analog circuit design  

CERN Document Server

Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

Dobkin, Bob

2012-01-01

222

The effect of glucose stimulation on 45calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method  

International Nuclear Information System (INIS)

Glucose-stimulated 45calcium uptake and total calcium content of rat pancreatic islets has been studied, using a new fluorometric micro-method to estimate total calcium. Extracellular calcium was separated from incubated tissue by a rapid micro-filtration procedure. Islets incubated up to 60 min with calcium chloride 2.5 mmol/l and glucose 2.5 mmol/l maintained the same calcium content (670 +- 7.5 pmol/?g DNA). When the glucose concentration was raised to 15 mmol/l no change in the total calcium content could be detected. On incubation with glucose 2.5 mmol/l in the absence of calcium, the calcium content decreased to 488 +- 27 pmol/?g DNA. On incubation with 45calcium chloride 2.5 mmol/l for 5 or 30 min at 2.5 mmol/l glucose, islets exchanged 21 +- 2 and 28 +- 1% of their total calcium content and, at 15 mmol/l glucose, 30 +- 3 and 45 +- 2%, respectively. Thus, islet calcium has a high turn-over rate. Glucose stimulation results in an increase of the calcium uptake without enhancing the total calcium content and hence must increase the calcium-exchangeable pool. (orig.)

223

Analog Codes on Graphs  

CERN Document Server

We consider the problem of transmission of a sequence of real data produced by a Nyquist sampled band-limited analog source over a band-limited analog channel, which introduces an additive white Gaussian noise. An analog coding scheme is described, which can achieve a mean-squared error distortion proportional to $(1+SNR)^{-B}$ for a bandwidth expansion factor of $B/R$, where $0 < R < 1$ is the rate of individual component binary codes used in the construction and $B \\geq 1$ is an integer. Thus, over a wide range of SNR values, the proposed code performs much better than any single previously known analog coding system.

Santhi, N; Santhi, Nandakishore; Vardy, Alexander

2006-01-01

224

Nonvolatile Analog Memory  

Science.gov (United States)

A nonvolatile analog memory uses pairs of ferroelectric field effect transistors (FFETs). Each pair is defined by a first FFET and a second FFET. When an analog value is to be stored in one of the pairs, the first FFET has a saturation voltage applied thereto, and the second FFET has a storage voltage applied thereto that is indicative of the analog value. The saturation and storage voltages decay over time in accordance with a known decay function that is used to recover the original analog value when the pair of FFETs is read.

MacLeod, Todd C. (Inventor)

2007-01-01

225

Analog synthetic biology.  

Science.gov (United States)

We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

Sarpeshkar, R

2014-03-28

226

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 ...

227

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 Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & ...

228

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... blood glucose) Hyperglycemia (High blood glucose) Dawn Phenomenon Checking for Ketones Tight Diabetes ... en -- At risk for type 2? - 2015-march-alert-engagement-image.html sticky ...

229

Blood Glucose Monitoring Devices  

Science.gov (United States)

... Glucose NIH Medline Plus - Diabetes Spotlight FDA permits marketing of first system of mobile medical apps for ... More in Products and Medical Procedures In Vitro Diagnostics Blood Glucose Monitoring Devices Page Last Updated: 01/ ...

230

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... often. Ask your doctor how often you should check and what your blood glucose levels should be. ... your blood glucose is above 240 mg/dl, check your urine for ketones. If you have ketones, ...

231

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 ...

232

[Non-pharmaceutical measures, topical analgesics and oral administration of glucose in pain management: Austrian interdisciplinary recommendations on pediatric perioperative pain management].  

Science.gov (United States)

Non-pharmaceutical procedures are increasingly being used in pediatric pain therapy in addition to pharmaceutical procedures and have a supporting function. This article describes the non-pharmaceutical procedures which have an influence on perioperative and posttraumatic pain in children and adolescents. Prerequisites for every adequate pain therapy are affection, imparting a feeling of security, distraction and the creation of a child-oriented environment. Topical analgesics are indicated for application to intact skin for surface anesthesia. For a safe use consideration must be given to the duration of application, the dose and the maximum area of skin treated in an age-dependent manner. For simple but painful procedures in premature infants, neonates and infants, pain can be effectively reduced by the oral administration of glucose. The positive effect is guaranteed particularly for the use in a once only pain stimulation. Non-nutritive sucking, swaddling, facilitated tucking and kangaroo mother care, for example can be used as supportive measures during slightly painful procedures. There is insufficient evidence for a pain reducing effect in older infants and small children. Physical therapeutic procedures can be used as accompanying measures for acute pain and are individually adapted. However, the limited amount of currently available data is insufficient to make a critical scientific assessment of the individual measures. The effects can, however, be observed in the daily routine practice. Psychological methods can facilitate coping with pain. In situations with mental and psychiatric comorbidities or psychosocial impairment, a psychologist should be consulted. Acupuncture and hypnosis are also a meaningful addition within the framework of multimodal pain therapy. PMID:24550025

Messerer, B; Krauss-Stoisser, B; Urlesberger, B

2014-02-01

233

Imaging atherosclerosis in the carotid arteries with F-18-Fluoro-2-deoxy-D-glucose positron emission tomography: effect of imaging time after injection on quantitative measurement  

Energy Technology Data Exchange (ETDEWEB)

To compare F-18-fluoro-2-deoxy-D-glucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) imaging at two different circulation times after injection of F-18 FDG in order to measure atherosclerosis in carotid arteries. We assessed 12 patients with recent symptomatic plaques in the carotid arteries. F-18 FDG PET/CT carotid plaque imaging was performed for 20 min at 2 h after F-18 FDG injection in five patients and at 3 h in seven patients. We measured vessel wall uptake using the maximal standardized uptake value (SUV), and the mean and maximal blood target-to-background ratios (TBR) of the symptomatic carotid arteries. Blood pool activity (BPA) was measured as the mean SUV of the superior vena cava (SVC) and jugular vein of these 12 patients, and in 14 age-and gender-matched patients who underwent whole-body F-18 FDG PET/CT examinations 1 h after injection. F-18 FDG PET/CT revealed visible F-18 FDG uptake in all patients with symptomatic carotid plaques. Maximal SUV did not differ between groups evaluated at 2 h and 3 h (2.62{+-}0.45 vs 3.00{+-}0.85, p=0.335). However mean (2.04{+-}0.22 vs 3.54{+-}0.62, p<0.05) and maximal (1.65{+-}0.15 vs 2.70{+-}0.42, p<0.05) TBR values that were normalized to BPA in the SVC differ significantly. Symptomatic carotid plaques are visualized for a relatively short period of imaging time on {>=}1-h PET/CT images. Quantitative parameters of atherosclerotic carotid arteries are preserved or even increased over time, whereas those of blood pools are decreased

Oh, Min Young; Kim, Ji Young; Shin, Kwang Ho; Park, Seol Hoon; Ryu, Jin Sook; Kim, Jae Seung; Kim, Hye Jin; Kang, Dong Wha; Moon, Dae Hyuk [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

2010-12-15

234

Detecting early kidney damage in horses with colic by measuring matrix metalloproteinase -9 and -2, other enzymes, urinary glucose and total proteins  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The aim of the study was to investigate urine matrix metalloproteinase (MMP-2 and -9 activity, alkaline phosphatase/creatinine (U-AP/Cr and gamma-glutamyl-transpeptidase/creatinine (U-GGT/Cr ratios, glucose concentration, and urine protein/creatinine (U-Prot/Cr ratio and to compare data with plasma MMP-2 and -9 activity, cystatin-C and creatinine concentrations in colic horses and healthy controls. Horses with surgical colic (n = 5 were compared to healthy stallions (n = 7 that came for castration. Blood and urine samples were collected. MMP gelatinolytic activity was measured by zymography. Results We found out that horses with colic had significantly higher urinary MMP-9 complex and proMMP-9 activities than horses in the control group. Colic horses also had higher plasma MMP-2 activity than the control horses. Serum creatinine, although within reference range, was significantly higher in the colic horses than in the control group. There was no significant increase in urinary alkaline phosphatase, gamma-glutamyltranspeptidase or total proteins in the colic horses compared to the control group. A human cystatin-C test (Dako Cytomation latex immunoassay® based on turbidimetry did not cross react with equine cystatin-C. Conclusion The results indicate that plasma MMP-2 may play a role in the pathogenesis of equine colic and urinary MMP-9 in equine kidney damage.

Salonen Hanna

2007-01-01

235

Does the Emotional Go/No-Go Task Really Measure Behavioral Inhibition? Convergence with Measures on a Non-Emotional Analog  

Science.gov (United States)

This study tested the convergence of behavioral inhibition measures across emotional and non-emotional versions of the same go/no-go task in 85 college students. The two tasks differed only in the stimuli used for trial cues (i.e., circles versus facial expressions). Moderate correlations (r = .51 to r = .56) between commission errors across the emotional and non-emotional tasks support the construct validity of behavioral inhibition. Further, parametric manipulation of preceding context had comparable effects on performance on the two tasks. Responses were slower and more variable, commission errors were more numerous, and perceptual sensitivity was lower on the emotional than the non-emotional task. A bias for happy faces on the emotional task resulted in faster responses and more commission errors for happy than sad faces despite marginally greater sensitivity for the latter. These results suggest that the basic neuropsychological constructs of the original go/no-go task were preserved in the emotional adaptation. PMID:17207962

Schulz, Kurt P.; Fan, Jin; Magidina, Olga; Marks, David J.; Hahn, Bella; Halperin, Jeffrey M.

2007-01-01

236

Quantification of the Variability of Continuous Glucose Monitoring Data  

Directory of Open Access Journals (Sweden)

Full Text Available Several measurements are used to describe the behavior of a diabetic patient’s blood glucose. We describe a new, wavelet-based algorithm that indicates a new measurement called a PLA index could be used to quantify the variability or predictability of blood glucose. This wavelet-based approach emphasizes the shape of a blood glucose graph. Using continuous glucose monitors (CGMs, this measurement could become a new tool to classify patients based on their blood glucose behavior and may become a new method in the management of diabetes.

Edward Aboufadel

2011-02-01

237

Total and high molecular weight (HMW) adiponectin levels and measures of glucose and lipid metabolism following pioglitazone treatment in a randomized placebo-controlled study in polycystic ovary syndrome  

DEFF Research Database (Denmark)

OBJECTIVE: Recent studies suggested that the effect of adiponectin on insulin-stimulated glucose metabolism is mediated primarily by the high molecular weight (HMW) form of adiponectin. In the present study we evaluated total and HMW adiponectin in polycystic ovary syndrome (PCOS) patients and controls and examined possible mechanisms for increased insulin sensitivity during pioglitazone treatment. STUDY SUBJECTS: Thirty PCOS patients randomized to pioglitazone, 30 mg/day, or placebo for 16 weeks and 14 weight-matched healthy females were studied. DESIGN: Total and HMW adiponectin levels were measured, and euglycaemic hyperinsulinaemic clamps and indirect calorimetry were performed. Delta-values denoted changes during pioglitazone treatment (16 weeks--basal). RESULTS: Pretreatment adiponectin levels were decreased in PCOS patients vs. controls (P < 0.05), whereas no significant differences were found in HMW adiponectin levels. Following pioglitazone treatment, total and HMW adiponectin increased (all P < 0.05), whereas no significant changes were observed with placebo. Delta-total adiponectin levels correlated positively with the rate of Delta-insulin-stimulated glucose disposal (R(d)) (r = 0.89) and Delta-oxidative glucose metabolism (r = 0.71) and inversely with Delta-fasting free fatty acid (FFA) levels (r = -0.69) and Delta-lipid oxidation (r = -0.73) during insulin stimulation (all P < 0.01). Weaker correlations were found between Delta-HMW adiponectin levels and Delta-measures of glucose and lipid metabolism during insulin stimulation than with Delta-total adiponectin. CONCLUSION: A close correlation between increased total adiponectin levels and increased insulin-stimulated glucose metabolism during pioglitzone treatment supports the hypothesis that the insulin-sensitizing effect of pioglitazone in PCOS is, at least in part, mediated by adiponectin. Measures of changes in HMW adiponectin did not add further information to this relationship Udgivelsesdato: 2008/2

Glintborg, D.; Frystyk, J.

2008-01-01

238

Role of oxygen vs. glucose in energy metabolism in a mammary carcinoma perfused ex vivo: direct measurement by 31P NMR.  

OpenAIRE

The role of glycolysis vs. respiration in tumor energy metabolism has been studied, to date, primarily in vitro by using single cells, multicellular spheroids, or tissue slices. With the advent of in vivo NMR spectroscopy, several investigators have shown that tumor energy status depends on its blood flow. Since manipulation of blood flow alters both oxygen and glucose delivery to a solid tumor, these studies have not been able to separate the relative contribution of oxygen vs. glucose in en...

Eskey, C. J.; Koretsky, A. P.; Domach, M. M.; Jain, R. K.

1993-01-01

239

Hydraulic Capacitor Analogy  

Science.gov (United States)

Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding. According to Iding, analogies are consistent with the tenets of constructivist learning…

Baser, Mustafa

2007-01-01

240

Analogies for Avogadro's Number.  

Science.gov (United States)

Reviews analogies used to try to capture the concept of the magnitude of Avogadro's number, including analogies related to small/tiny objects, counting, people, water, and money. Also presents several new ones which are based on modern computers and printers. (JN)

Poskozim, Paul S.; And Others

1986-01-01

241

Integration of [U-13C]glucose and 2H2O for quantification of hepatic glucose production and gluconeogenesis  

OpenAIRE

Glucose metabolism in five healthy subjects fasted for 16 h was measured with a combination of [U-13C]glucose and 2H2O tracers. Phenylbutyric acid was also provided to sample hepatic glutamine for the presence of 13C-isotopomers derived from the incorporation of [U-13C]glucose products into the hepatic Krebs cycle. Glucose production (GP) was quantified by 13C NMR analysis of the monoacetone derivative of plasma glucose following a primed infusion of [U-13C]glucose and provided reasonable es...

Perdigoto, Rui; Rodrigues, Tiago B.; Furtado, Alexandre L.; Porto, Armando; Geraldes, Carlos F. G. C.; Jones, John G.

2003-01-01

242

Glucose turnover, gluconeogenesis from glycerol, and estimation of net glucose cycling in cancer patients  

International Nuclear Information System (INIS)

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-14C]glycerol and [6-3H]glucose were given intravenously as a single dose injection. The time course of the specific radioactivities of [6-3H] and [U-14C]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 [14C]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 igenesis 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

243

Glucose-dependent Insulinotropic Polypeptide : Blood Glucose Stabilizing Effects in Patients With Type 2 Diabetes  

DEFF Research Database (Denmark)

CONTEXT: Patients with type 2 diabetes mellitus (T2DM) have clinically relevant disturbances in the effects of the hormone glucose-dependent insulinotropic polypeptide (GIP). OBJECTIVE: We aimed to evaluate the importance of the prevailing plasma glucose levels for the effect of GIP on responses of glucagon and insulin and glucose disposal in patients with T2DM. DESIGN AND SETTING: We performed a single center, placebo-controlled, cross-over, experimental study. PATIENTS: We studied twelve patients with T2DM (age: 62 ± 1 years [mean ± SEM], body mass index: 29 ± 1 kg/m(2); glycosylated hemoglobin A1c: 6.5 ± 0.1% [48 ± 2 mmol/mol]). INTERVENTION: We infused physiological amounts of GIP (2 pmol × kg(-1) × min(-1)) or saline. MAIN OUTCOME MEASURES: We measured plasma concentrations of glucagon, glucose, insulin, C-peptide, intact GIP, and amounts of glucose needed to maintain glucose clamps. RESULTS: During fasting glycemia (plasma glucose ?8 mmol/L), GIP elicited significant increments in both insulin andglucagon levels, resulting in neutral effects on plasma glucose. During insulin-induced hypoglycemia (plasma glucose ?3 mmol/L), GIP elicited a minor early-phase insulin response and increased glucagon levels during the initial 30 minutes, resulting in less glucose needed to be infused to maintain the clamp (29 ± 8 vs 49 ± 12 mg × kg(-1), P < .03). During hyperglycemia (1.5 × fasting plasma glucose ?12 mmol/L), GIP augmented insulin secretion throughout the clamp, with slightly less glucagon suppression compared with saline, resulting in more glucose needed to maintain the clamp during GIP infusions (265 ± 21 vs 213 ± 13 mg × kg(-1), P < .001). CONCLUSIONS: In patients with T2DM, GIP counteracts insulin-induced hypoglycemia, most likely through a predominant glucagonotropic effect. In contrast, during hyperglycemia, GIP increases glucose disposal through a predominant effect on insulin release.

Christensen, Mikkel B; Calanna, Salvatore

2014-01-01

244

Plasma glucose levels and flight  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Noise is able to exert many adverse health effects, ranging from damages on various organs and systems to changes in biochemical and humoral markers. In literature, the effects of chronic exposure to noise on blood glucose levels have been reported, although these results are conflicting: some authors reported hyperglycaemia, others hypoglycaemia and many others recorded no changes in blood glucose levels. Objectives: Considering that the plasma glucose levels are not used as a biomarker of noise exposure, we conducted a pilot study on 6 subjects, 2 females and 4 males, working as clerks in a low noise environment in order to evaluate the possible occurrence of changes on plasma glucose levels in healthy subjects, non-diabetic and not accustomed to flight, exposed to noise and to flight-related stressors. Methods: The subjects completed a specific clinic-anamnestic questionnaire and underwent a general clinical examination. In the first phase of the study, participants underwent blood tests in order to assess the plasma glucose levels at three different times: at 8:00 a.m., on board of a turboprop transport aircraft before the take-off with the engine switched off, after 60 and 120 minutes’ flight. The second phase of the study was carried out one month after the first one and while working in the office; three blood tests were performed again, at fasting and after 60 and 120 minutes. The plasma glucose levels were measured on capillary blood by the refractometry method through the use of Glucoscan One Touch device. Results: The results show an increase of plasma glucose levels during the waiting for the flight and a statistically significant decrease of plasma glucose levels in the first hour of flight (p <0.001, persisting even at the second hour (p <0.001. No significant changes were found in the blood tests performed at work. Discussion: The data show an initial hyperglycaemic response, followed by a persistent and moderate decrease of glycaemia; a similar response was not observed in the same subjects during ordinary work activities. The Authors believe that the initial increase of the plasma glucose levels, recorded in absence of noise on board, could be related to the response to other stressors, such as anxiety linked to the waiting for the flight. The decrease of the plasma glucose levels observed after 60 and 120 minutes’ flight, that is in conditions of prolonged exposure to flight-related stressors and to noise, may be linked to the intervention of several mechanisms: partial phenomenon of adaptation-exhaustion of the neuroendocrine response to stress; hypoglycaemic effect of noise, CCK-mediated and VIP-mediated with consequent insulin release and decrease of the plasma glucose levels; synergistic action of the above mechanisms. The absence of changes on the plasma glucose levels during the usual work activity is probably due to the absence of those stressors considered able to induce the alterations of the plasma glucose levels recorded during the first phase of the study. Conclusions: These preliminary results suggest that exposure to flight-related stressors and in particular exposure to noise can cause a hypoglycaemic response.

Tomei G

2013-07-01

245

Yak1p, a DYRK family kinase, translocates to the nucleus and phosphorylates yeast Pop2p in response to a glucose signal  

OpenAIRE

POP2 protein of Saccharomyces cerevisiae is a component of a protein complex that regulates the transcription of many genes. We found that the 97th threonine residue (Thr 97) of Pop2p was phosphorylated upon glucose limitation. The Thr 97 phosphorylation occurred within 2 min after removing glucose and was reversed within 1 min after the readdition of glucose. The effects of hexokinase mutations and glucose analogs indicate that this phosphorylation is dependent on glucose phosphorylating act...

Moriya, Hisao; Shimizu-yoshida, Yuki; Omori, Akira; Iwashita, Shintaro; Katoh, Mariko; Sakai, Akira

2001-01-01

246

Effects of lindane on the glucose metabolism in rat brain cortex cells  

International Nuclear Information System (INIS)

The influence of 0.5 mM ?-hexachlorocyclohexane (?-HCH, lindane) on glucose transport has been investigated using the analog 3-O-methyl-D(U-14C) glucose. The glucose uptake was lineal for at least 10 sec. Preincubation of dissociated brain cortex cells with lindane decreased the transport of glucose with respect to the controls. The treatment of brain cortex cells with other organochlorine compounds indicated that the ?-, ?-HCH isomers and dieldrin reproduced the same inhibitory pattern, while ?-HCH and endrin were inactive. The total radioactivity incorporated into CO2 from (U-14C) glucose in the cerebral cortex is also inhibited by lindane in a time dependent manner

247

In Vitro Evaluation of Fluorescence Glucose Biosensor Response  

OpenAIRE

Rapid, accurate, and minimally-invasive glucose biosensors based on Förster Resonance Energy Transfer (FRET) for glucose measurement have the potential to enhance diabetes control. However, a standard set of in vitro approaches for evaluating optical glucose biosensor response under controlled conditions would facilitate technological innovation and clinical translation. Towards this end, we have identified key characteristics and response test methods, fabricated FRET-based glucose biosenso...

Mamdouh Aloraefy; Joshua Pfefer, T.; Ramella-roman, Jessica C.; Sapsford, Kim E.

2014-01-01

248

Meat analog: a review.  

Science.gov (United States)

The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers. PMID:24915320

Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S

2015-07-29

249

Analog modelling of obduction processes  

Science.gov (United States)

Obduction corresponds to one of plate tectonics oddities, whereby dense, oceanic rocks (ophiolites) are presumably 'thrust' on top of light, continental ones, as for the short-lived, almost synchronous Peri-Arabic obduction (which took place along thousands of km from Turkey to Oman in c. 5-10 Ma). Analog modelling experiments were performed to study the mechanisms of obduction initiation and test various triggering hypotheses (i.e., plate acceleration, slab hitting the 660 km discontinuity, ridge subduction; Agard et al., 2007). The experimental setup comprises (1) an upper mantle, modelled as a low-viscosity transparent Newtonian glucose syrup filling a rigid Plexiglas tank and (2) high-viscosity silicone plates (Rhodrosil Gomme with PDMS iron fillers to reproduce densities of continental or oceanic plates), located at the centre of the tank above the syrup to simulate the subducting and the overriding plates - and avoid friction on the sides of the tank. Convergence is simulated by pushing on a piston at one end of the model with velocities comparable to those of plate tectonics (i.e., in the range 1-10 cm/yr). The reference set-up includes, from one end to the other (~60 cm): (i) the piston, (ii) a continental margin containing a transition zone to the adjacent oceanic plate, (iii) a weakness zone with variable resistance and dip (W), (iv) an oceanic plate - with or without a spreading ridge, (v) a subduction zone (S) dipping away from the piston and (vi) an upper, active continental margin, below which the oceanic plate is being subducted at the start of the experiment (as is known to have been the case in Oman). Several configurations were tested and over thirty different parametric tests were performed. Special emphasis was placed on comparing different types of weakness zone (W) and the extent of mechanical coupling across them, particularly when plates were accelerated. Displacements, together with along-strike and across-strike internal deformation in all plates were systematically measured, allowing for a very precise and reproducible tracking of deformation. Experiments demonstrate that obduction chiefly depends on how the overall shortening (or convergence) is partitionned between the weakness zone (W) and the preexisting subduction zone (S). Conditions favorable to obduction are shown to correspond to a specific range of coupling across (S) and resistance across (W). Our results thereby (1) constrain the range of physical conditions required for obduction to develop/nucleate and (2) underline the key role of acceleration for triggering obduction (rather than ridge subduction or slab resistance to penetration at the 660 km discontinuity). They also demonstrate that the emplacement of dense, oceanic material on continental lithosphere is not a mysterious process but results from some large scale, normal subduction process that do not require exotic boundary conditions. Agard P., Jolivet L., Vrielynck B., Burov E. & Monié P., 2007. Plate acceleration : the obduction trigger? Earth and Planetary Science Letters, 258, 428-441.

Agard, P.; Zuo, X.; Funiciello, F.; Bellahsen, N.; Faccenna, C.; Savva, D.

2012-04-01

250

Statins Impair Glucose Uptake in Tumor Cells  

Directory of Open Access Journals (Sweden)

Full Text Available Statins, HMG-CoA reductase inhibitors, are used in the prevention and treatment of cardiovascular diseases owing to their lipid-lowering effects. Previous studies revealed that, by modulating membrane cholesterol content, statins could induce conformational changes in cluster of differentiation 20 (CD20 tetraspanin. The aim of the presented study was to investigate the influence of statins on glucose transporter 1 (GLUT1-mediated glucose uptake in tumor cells. We observed a significant concentration- and time-dependent decrease in glucose analogs' uptake in several tumor cell lines incubated with statins. This effect was reversible with restitution of cholesterol synthesis pathway with mevalonic acid as well as with supplementation of plasma membrane with exogenous cholesterol. Statins did not change overall GLUT1 expression at neither transcriptional nor protein levels. An exploratory clinical trial revealed that statin treatment decreased glucose uptake in peripheral blood leukocytes and lowered 18F-fluorodeoxyglucose (18F-FDG uptake by tumor masses in a mantle cell lymphoma patient. A bioinformatics analysis was used to predict the structure of human GLUT1 and to identify putative cholesterol-binding motifs in its juxtamembrane fragment. Altogether, the influence of statins on glucose uptake seems to be of clinical significance. By inhibiting 18F-FDG uptake, statins can negatively affect the sensitivity of positron emission tomography, a diagnostic procedure frequently used in oncology.

Agata Malenda

2012-04-01

251

Statins impair glucose uptake in tumor cells.  

Science.gov (United States)

Statins, HMG-CoA reductase inhibitors, are used in the prevention and treatment of cardiovascular diseases owing to their lipid-lowering effects. Previous studies revealed that, by modulating membrane cholesterol content, statins could induce conformational changes in cluster of differentiation 20 (CD20) tetraspanin. The aim of the presented study was to investigate the influence of statins on glucose transporter 1 (GLUT1)-mediated glucose uptake in tumor cells. We observed a significant concentration- and time-dependent decrease in glucose analogs' uptake in several tumor cell lines incubated with statins. This effect was reversible with restitution of cholesterol synthesis pathway with mevalonic acid as well as with supplementation of plasma membrane with exogenous cholesterol. Statins did not change overall GLUT1 expression at neither transcriptional nor protein levels. An exploratory clinical trial revealed that statin treatment decreased glucose uptake in peripheral blood leukocytes and lowered (18)F-fluorodeoxyglucose ((18)F-FDG) uptake by tumor masses in a mantle cell lymphoma patient. A bioinformatics analysis was used to predict the structure of human GLUT1 and to identify putative cholesterol-binding motifs in its juxtamembrane fragment. Altogether, the influence of statins on glucose uptake seems to be of clinical significance. By inhibiting (18)F-FDG uptake, statins can negatively affect the sensitivity of positron emission tomography, a diagnostic procedure frequently used in oncology. PMID:22577346

Malenda, Agata; Skrobanska, Anna; Issat, Tadeusz; Winiarska, Magdalena; Bil, Jacek; Oleszczak, Bozenna; Sinski, Maciej; Firczuk, Ma?gorzata; Bujnicki, Janusz M; Chlebowska, Justyna; Staruch, Adam D; Glodkowska-Mrowka, Eliza; Kunikowska, Jolanta; Krolicki, Leszek; Szablewski, Leszek; Gaciong, Zbigniew; Koziak, Katarzyna; Jakobisiak, Marek; Golab, Jakub; Nowis, Dominika A

2012-04-01

252

Detecção de trombose venosa em retalhos livres por medidas de glicemia capilar Detection of venous thrombosis in free flaps by measurement of capillary blood glucose  

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUÇÃO: A monitorização do retalho livre após a cirurgia é de vital importância, especialmente nas primeiras horas de pós-operatório, pois o momento de reabordagem pode ser o definidor entre o salvamento ou a perda do retalho. Até o momento, não existe trabalho na literatura estudando a decisão de abordagem do retalho baseada em medidas objetivas ou a comparação da glicemia entre retalhos que evoluíram bem com os que sofreram sofrimento vascular. O objetivo deste estudo é avaliar a validade da medida da glicemia capilar do retalho como método de monitorização de retalhos microcirúrgicos comparando com a avaliação clínica. MÉTODO: Foram estudados prospectivamente 16 pacientes portadores de retalhos livres, realizados de maio de 2012 a julho de 2012. A glicemia capilar foi avaliada por equipe formada por profissionais não envolvidos com a cirurgia realizada. A avaliação clínica do retalho foi realizada no pós-operatório imediato, na chegada à UTI, a cada 3 horas e sempre que necessário. RESULTADOS: Dos 16 pacientes, 5 (31,3% apresentaram complicações nas primeiras 24 horas. Todas as complicações observadas foram trombose venosa. Foi observada diferença estatisticamente significante na glicemia capilar de portadores de retalhos que apresentaram trombose venosa em comparação àqueles que não tiveram a complicação, nas medidas realizadas 6 horas, 9 horas e 12 horas após a operação (P BACKGROUND: Monitoring of free flaps after surgery is vitally important, especially in the first few hours because the timing of reoperation can determine flap salvage or loss. To date, no study has examined the decision to reoperate on a flap based on the objective measure of glycemia or a comparison between flaps that showed good outcomes and those that showed vascular damage. The objective of this study was to evaluate the validity of blood glucose measurements within the flap as a method for monitoring free flaps and to compare the efficacy of this method with that of clinical assessments. METHODS: The study was prospective, included 16 patients with free flaps, and was conducted from May 2012 to July 2012. A team of professionals not involved in the surgery evaluated capillary glycemia. Flaps were clinically evaluated during the immediate postoperative period, on ICU admission, at every 3 hours, and as needed. RESULTS: Of the 16 patients, 5 (31.3% had venous thrombosis in the first 24 hours. Statistically significant differences were noted in capillary glycemia in patients with or without venous thrombosis in measurements obtained 6, 9, and 12 hours after surgery (P < 0.05. CONCLUSIONS: The measurement of capillary glycemia was not superior to clinical evaluation by an experienced professional for the detection of venous thrombosis within free flaps.

Lincoln Saito Millan

2012-12-01

253

Development of Analogy Experiment Methodologies  

International Nuclear Information System (INIS)

Hydrogen is expected to help address concerns about global climate change and energy security. The HTGR (High-Temperature Gas-cooled Reactor) drew attention as one of the most competitive heat source for producing hydrogen. The knowledge of detailed heat transfer phenomena in gaseous phase emerges as an important factor for HTGR, where buoyancy effect plays a significant role. Large and expensive test facilities are to be constructed to assess the detailed mixed convection phenomena. However, using analogy concept, heat transfer system can be transformed to mass transfer system(copper electroplating system) and vice versa. If we could devise simple mass transfer system and find experimental solution from that system, then theoretically it is not difficult to find solution for similar heat transfer system. This study explores the applicability of simple mass transfer experiments to heat transfer researches using analogy concept. A copper electroplating system with limiting current technique has a good advantage to simulate heat transfer system as mass transfer coefficient, analogous with heat transfer coefficient, can be directly obtained from the information of the bulk concentration and electric current between electrodes. Therefore, the validity of the analogy experimental method was confirmed through comparison between the test results obtained by measuring limiting current and corresponding well-known heat transfer correlations. Three different forced and natural tions. Three different forced and natural convection mass transfer systems were constructed to simulate Poiseuille flow at horizontal geometry and laminar and turbulent buoyant flows at vertical geometry. it was shown that the close agreement between results for mass transfer experiment and heat transfer correlation is an encouraging indication of the validity of the analogy theory and the experiment method. It may also be concluded that analogy method using electroplating system make it possible to predict the unknown heat transfer correlations. Thus, Analogy methodology is expected to be a useful tool for heat transfer studies for HTGR development as the electroplating method not only provide with useful information on heat transfer but also has cost-effective advantage than any other experiments

254

Modeling the glucose sensor error.  

Science.gov (United States)

Continuous glucose monitoring (CGM) sensors are portable devices, employed in the treatment of diabetes, able to measure glucose concentration in the interstitium almost continuously for several days. However, CGM sensors are not as accurate as standard blood glucose (BG) meters. Studies comparing CGM versus BG demonstrated that CGM is affected by distortion due to diffusion processes and by time-varying systematic under/overestimations due to calibrations and sensor drifts. In addition, measurement noise is also present in CGM data. A reliable model of the different components of CGM inaccuracy with respect to BG (briefly, "sensor error") is important in several applications, e.g., design of optimal digital filters for denoising of CGM data, real-time glucose prediction, insulin dosing, and artificial pancreas control algorithms. The aim of this paper is to propose an approach to describe CGM sensor error by exploiting n multiple simultaneous CGM recordings. The model of sensor error description includes a model of blood-to-interstitial glucose diffusion process, a linear time-varying model to account for calibration and sensor drift-in-time, and an autoregressive model to describe the additive measurement noise. Model orders and parameters are identified from the n simultaneous CGM sensor recordings and BG references. While the model is applicable to any CGM sensor, here, it is used on a database of 36 datasets of type 1 diabetic adults in which n = 4 Dexcom SEVEN Plus CGM time series and frequent BG references were available simultaneously. Results demonstrates that multiple simultaneous sensor data and proper modeling allow dissecting the sensor error into its different components, distinguishing those related to physiology from those related to technology. PMID:24108706

Facchinetti, Andrea; Del Favero, Simone; Sparacino, Giovanni; Castle, Jessica R; Ward, W Kenneth; Cobelli, Claudio

2014-03-01

255

Genetic variation in GIPR influences the glucose and insulin responses to an oral glucose challenge  

OpenAIRE

Glucose levels 2 h after an oral glucose challenge are a clinical measure of glucose tolerance used in the diagnosis of type 2 diabetes. We report a meta-analysis of nine genome-wide association studies (n = 15,234 nondiabetic individuals) and a follow-up of 29 independent loci (n = 6,958-30,620). We identify variants at the GIPR locus associated with 2-h glucose level (rs10423928, beta (s.e.m.) = 0.09 (0.01) mmol/l per A allele, P = 2.0 x 10(-15)). The GIPR A-allele carriers also showed decr...

Saxena, R.; Hivert, Mf; Langenberg, C.; Tanaka, T.; Pankow, Js; Vollenweider, P.; Lyssenko, V.; Bouatia-naji, N.; Dupuis, J.; Jackson, Au; Kao, Wh; Li, M.; Glazer, Nl; Manning, Ak; Luan, J.

2010-01-01

256

Glucose Recognition in Vitro Using Fluorescent Spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

Diabetes is a disease that affects over 16 million people in the USA at a cost of 100 billion dollars annually. The ability to regulate insulin delivery in people with Type 1 diabetes is imperative as is the need to manage glucose levels in all people with this disease. Our current method for monitoring glucose is a (FDA approved) minimally invasive enzymatic sensor that can measure glucose levels in vivo for three days. We are focused on developing a noninvasive implantable glucose sensor that will be interrogated by an external device. The material must be robust, easy to process, biocompatible and resistant to biofouling. In this Presentation we will discuss the development of a new polymeric matrix that can recognize physiological levels of glucose in vitro using fluorescent spectroscopy.

Noronha, G; Heiss, A M; Reilly, J R; Vachon, Jr, D J; Cary, D R; Zaitseva, N P; Reibold, R A; Lane, S M; Peyser, T A; Satcher, J H

2001-04-25

257

Korean Red Ginseng Improves Glucose Control in Subjects with Impaired Fasting Glucose, Impaired Glucose Tolerance, or Newly Diagnosed Type 2 Diabetes Mellitus  

OpenAIRE

This study was designed to evaluate the effect of Korean red ginseng (KRG) supplementation on glucose control in subjects with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or newly diagnosed type 2 diabetes mellitus (T2DM). The study was a 12-week randomized, double-blinded, placebo-controlled (5?g of KRG [n=21] or placebo [n=20] in tablet form) trial. Glucose-related biomarkers, including serum and whole blood levels of glucose, insulin, and C-peptide, were measured by...

Bang, Hyangju; Kwak, Jung Hyun; Ahn, Hyeon Yeong; Shin, Dong Yeob; Lee, Jong Ho

2014-01-01

258

Detecção de trombose venosa em retalhos livres por medidas de glicemia capilar / Detection of venous thrombosis in free flaps by measurement of capillary blood glucose  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Languages: English, Portuguese Abstract in portuguese INTRODUÇÃO: A monitorização do retalho livre após a cirurgia é de vital importância, especialmente nas primeiras horas de pós-operatório, pois o momento de reabordagem pode ser o definidor entre o salvamento ou a perda do retalho. Até o momento, não existe trabalho na literatura estudando a decisão [...] de abordagem do retalho baseada em medidas objetivas ou a comparação da glicemia entre retalhos que evoluíram bem com os que sofreram sofrimento vascular. O objetivo deste estudo é avaliar a validade da medida da glicemia capilar do retalho como método de monitorização de retalhos microcirúrgicos comparando com a avaliação clínica. MÉTODO: Foram estudados prospectivamente 16 pacientes portadores de retalhos livres, realizados de maio de 2012 a julho de 2012. A glicemia capilar foi avaliada por equipe formada por profissionais não envolvidos com a cirurgia realizada. A avaliação clínica do retalho foi realizada no pós-operatório imediato, na chegada à UTI, a cada 3 horas e sempre que necessário. RESULTADOS: Dos 16 pacientes, 5 (31,3%) apresentaram complicações nas primeiras 24 horas. Todas as complicações observadas foram trombose venosa. Foi observada diferença estatisticamente significante na glicemia capilar de portadores de retalhos que apresentaram trombose venosa em comparação àqueles que não tiveram a complicação, nas medidas realizadas 6 horas, 9 horas e 12 horas após a operação (P Abstract in english BACKGROUND: Monitoring of free flaps after surgery is vitally important, especially in the first few hours because the timing of reoperation can determine flap salvage or loss. To date, no study has examined the decision to reoperate on a flap based on the objective measure of glycemia or a comparis [...] on between flaps that showed good outcomes and those that showed vascular damage. The objective of this study was to evaluate the validity of blood glucose measurements within the flap as a method for monitoring free flaps and to compare the efficacy of this method with that of clinical assessments. METHODS: The study was prospective, included 16 patients with free flaps, and was conducted from May 2012 to July 2012. A team of professionals not involved in the surgery evaluated capillary glycemia. Flaps were clinically evaluated during the immediate postoperative period, on ICU admission, at every 3 hours, and as needed. RESULTS: Of the 16 patients, 5 (31.3%) had venous thrombosis in the first 24 hours. Statistically significant differences were noted in capillary glycemia in patients with or without venous thrombosis in measurements obtained 6, 9, and 12 hours after surgery (P

Lincoln Saito, Millan; Luiz Carlos, Ishida; Esther Mihwa Oh, Choi; Enio Cesar, Giacchetto Junior; Teng Hsiang, Wei; Rames, Mattar Júnior; Marcus Castro, Ferreira.

2012-12-01

259

Toward CMOS image sensor based glucose monitoring.  

Science.gov (United States)

Complementary metal oxide semiconductor (CMOS) image sensor is a powerful tool for biosensing applications. In this present study, CMOS image sensor has been exploited for detecting glucose levels by simple photon count variation with high sensitivity. Various concentrations of glucose (100 mg dL(-1) to 1000 mg dL(-1)) were added onto a simple poly-dimethylsiloxane (PDMS) chip and the oxidation of glucose was catalyzed with the aid of an enzymatic reaction. Oxidized glucose produces a brown color with the help of chromogen during enzymatic reaction and the color density varies with the glucose concentration. Photons pass through the PDMS chip with varying color density and hit the sensor surface. Photon count was recognized by CMOS image sensor depending on the color density with respect to the glucose concentration and it was converted into digital form. By correlating the obtained digital results with glucose concentration it is possible to measure a wide range of blood glucose levels with great linearity based on CMOS image sensor and therefore this technique will promote a convenient point-of-care diagnosis. PMID:22764059

Devadhasan, Jasmine Pramila; Kim, Sanghyo

2012-09-01

260

Chemosensitizing and cytotoxic effects of 2-deoxy-D-glucose on breast cancer cells  

OpenAIRE

Background: Accelerated glucose uptake for anerobic glycolysis is one of the major metabolic changes found in malignant cells. This property has been exploited for imaging malignancies and as a possible anticancer therapy. The nonmetabolizable glucose analog 2-deoxyglucose (2?DG) interferes with glucose metabolism leading to breast cancer cell death. Aims: To determine whether 2DG can synergize with chemotherapeutic agents commonly used in breast cancer treatment and identify cellula...

Zhang Fanjie; Aft Rebecca

2009-01-01

261

Conformational changes in the intestinal brush border sodium-glucose cotransporter labeled with fluorescein isothiocyanate.  

OpenAIRE

Fluorescein isothiocyanate (FITC) was used to label the rabbit intestinal brush border Na+-glucose carrier, identify the carrier protein on sodium dodecyl sulfate/polyacrylamide gel electrophoresis, and monitor the effect of ions and substrates on fluorescence quenching. Enriched brush border preparations were employed to study both glucose transport and FITC binding. FITC and a nonfluorescent analog (phenyl isothiocyanate, PITC) both inhibited Na+-dependent D-glucose transport irreversibly. ...

Peerce, B. E.; Wright, E. M.

1984-01-01

262

Response variability to glucose facilitation of cognitive enhancement.  

Science.gov (United States)

Glucose facilitation of cognitive function has been widely reported in previous studies (including our own). However, several studies have also failed to detect glucose facilitation. There is sparsity of research examining the factors that modify the effect of glucose on cognition. The aims of the present study were to (1) demonstrate the previously observed enhancement of cognition through glucose administration and (2) investigate some of the factors that may exert moderating roles on the behavioural response to glucose, including glucose regulation, body composition (BC) and hypothalamic–pituitary–adrenal axis response. A total of twenty-four participants took part in a double-blind, placebo-controlled, randomised, repeated-measures study, which examined the effect of 25 and 60 g glucose compared with placebo on cognitive function. At 1 week before the study commencement, all participants underwent an oral glucose tolerance test. Glucose facilitated performance on tasks of numeric and spatial working memory, verbal declarative memory and speed of recognition. Moderating variables were examined using several indices of glucoregulation and BC. Poorer glucoregulation predicted improved immediate word recall accuracy following the administration of 25 g glucose compared with placebo. Those with better glucoregulation showed performance decrements on word recall accuracy following the administration of 25 g glucose compared with placebo. These findings are in line with accumulating evidence that glucose load may preferentially enhance cognition in those with poorer glucoregulation. Furthermore, the finding that individuals with better glucoregulation may suffer impaired performance following a glucose load is novel and requires further substantiation. PMID:23789911

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

2013-11-01

263

Analog for the Mac  

Science.gov (United States)

In addition to providing any number of web servicing capabilities, web servers are excellent at generating huge log files containing the details of their every activity. Analyzing these logs by hand is not practical. Fortunately, Stephen Turner has written Analog, a fast, freely-available, configurable tool for automatically analyzing log files. Jason T. Linhart, author of the shareware log analysis tool, Summary, has ported Analog to the MacOS.

264

A Fuzzy Model for Analogical Problem Solving  

CERN Document Server

In this paper we develop a fuzzy model for the description of the process of Analogical Reasoning by representing its main steps as fuzzy subsets of a set of linguistic labels characterizing the individuals' performance in each step and we use the Shannon- Wiener diversity index as a measure of the individuals' abilities in analogical problem solving. This model is compared with a stochastic model presented in author's earlier papers by introducing a finite Markov chain on the steps of the process of Analogical Reasoning. A classroom experiment is also presented to illustrate the use of our results in practice.

Voskoglou, Michael Gr

2012-01-01

265

Analog-antianalog transitions in arsenic isotopes  

International Nuclear Information System (INIS)

The ? decay of analog resonances in arsenic isotopes has been experimentally studied. The investigation was carried out at the 5 MeV Van de Graaff accelerator. The ? spectrum was measured by Ge(Li) detectors. Calculations of the strength functions and probabilities of the MI transitions from the gsub(9/2) and dsub(5/2) analog in 73As and 75As isotopes as well as from the Psub(1/2) analog in 75As are presented . The calculations were performed in terms of the model with the Gamow-Teller residual interaction

266

Glucose-Insulin  

Science.gov (United States)

Glucose is the vehicle by which energy gets from digested food to the cells of the body. In Type I diabetes mellitus, insufficient insulin is available to help get glucose out of the blood and into the cells of the body. This activity has been designed so that students can investigate the negative feedback loop between blood glucose and insulin, one of the mechanisms designed to maintain homeostasis in the human body.

Maryland Virtual High School

267

Blood Glucose Levels  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this study was to establish a mathematical model which can be used to estimate glucose levels in the blood over time. The equations governing this process were manipulated with the use of techniques such as separation of variables and integration of first order differential equations, which resulted in a function that described the glucose concentration in terms of time. This function was then plotted, which allowed us to find when glucose concentration was at its highest. The model was then used to analyze two cases where the maximum glucose level could not exceed a certain level while the amount of carbohydrates and glycemic index were varied, independently.

Carlos Estela

2011-01-01

268

Automated Generation of Cross-Domain Analogies via Evolutionary Computation  

CERN Document Server

Analogy plays an important role in creativity, and is extensively used in science as well as art. In this paper we introduce a technique for the automated generation of cross-domain analogies based on a novel evolutionary algorithm (EA). Unlike existing work in computational analogy-making restricted to creating analogies between two given cases, our approach, for a given case, is capable of creating an analogy along with the novel analogous case itself. Our algorithm is based on the concept of "memes", which are units of culture, or knowledge, undergoing variation and selection under a fitness measure, and represents evolving pieces of knowledge as semantic networks. Using a fitness function based on Gentner's structure mapping theory of analogies, we demonstrate the feasibility of spontaneously generating semantic networks that are analogous to a given base network.

Baydin, Atilim Gunes; Ontanon, Santiago

2012-01-01

269

Exenatide Sensitizes Insulin-Mediated Whole-Body Glucose Disposal and Promotes Uptake of Exogenous Glucose by the Liver  

Science.gov (United States)

OBJECTIVE— Recent progress suggests that exenatide, a mimetic of glucagon-like peptide-1 (GLP-1), might lower glycemia independent of increased ?-cell response or reduced gastrointestinal motility. We aimed to investigate whether exenatide stimulates glucose turnover directly in insulin-responsive tissues dependent or independent of insulinemia. RESEARCH DESIGN AND METHODS— An intraportal glucose infusion clamp was used in dogs to measure glucose turnover to encompass potent activation of the putative glucose/GLP-1 sensor in the porto-hepatic circulation with exenatide. The modified glucose clamp was performed in the presence of postprandial hyperinsulinemia and hyperglycemia with exenatide (20 ?g) or saline injected at 0 min. Furthermore, the role of hyperglycemia versus hyperinsulinemia in exenatide-mediated glucose disposal was studied. RESULTS— With hyperinsulinemia and hyperglycemia, exenatide produced a significant increase in total glucose turnover by ?30%, as indicated by portal glucose infusion rate (saline 15.9 ± 1.6 vs. exenatide 20.4 ± 2.1 mg · kg?1 · min?1, P < 0.001), resulting from increased whole-body glucose disposal (Rd, ?20%) and increased net hepatic uptake of exogenous glucose (?80%). Reducing systemic hyperglycemia to euglycemia, exenatide still increased total glucose turnover by ?20% (saline 13.2 ± 1.9 vs. exenatide 15.6 ± 2.1 mg · kg?1 · min?1, P < 0.05) in the presence of hyperinsulinemia, accompanied by smaller increments in Rd (12%) and net hepatic uptake of exogenous glucose (45%). In contrast, reducing hyperinsulinemia to basal levels, exenatide-increased total glucose turnover was completely abolished despite hyperglycemia (saline 2.9 ± 0.6 vs. exenatide 2.3 ± 0.3 mg · kg?1 · min?1, P = 0.29). CONCLUSIONS— Exenatide directly stimulates glucose turnover by enhancing insulin-mediated whole-body glucose disposal and increasing hepatic uptake of exogenous glucose, contributing to its overall action to lower postprandial glucose excursions. PMID:19011168

Zheng, Dan; Ionut, Viorica; Mooradian, Vahe; Stefanovski, Darko; Bergman, Richard N.

2009-01-01

270

GLUT2, glucose sensing and glucose homeostasis.  

Science.gov (United States)

The glucose transporter isoform GLUT2 is expressed in liver, intestine, kidney and pancreatic islet beta cells, as well as in the central nervous system, in neurons, astrocytes and tanycytes. Physiological studies of genetically modified mice have revealed a role for GLUT2 in several regulatory mechanisms. In pancreatic beta cells, GLUT2 is required for glucose-stimulated insulin secretion. In hepatocytes, suppression of GLUT2 expression revealed the existence of an unsuspected glucose output pathway that may depend on a membrane traffic-dependent mechanism. GLUT2 expression is nevertheless required for the physiological control of glucose-sensitive genes, and its inactivation in the liver leads to impaired glucose-stimulated insulin secretion, revealing a liver-beta cell axis, which is likely to be dependent on bile acids controlling beta cell secretion capacity. In the nervous system, GLUT2-dependent glucose sensing controls feeding, thermoregulation and pancreatic islet cell mass and function, as well as sympathetic and parasympathetic activities. Electrophysiological and optogenetic techniques established that Glut2 (also known as Slc2a2)-expressing neurons of the nucleus tractus solitarius can be activated by hypoglycaemia to stimulate glucagon secretion. In humans, inactivating mutations in GLUT2 cause Fanconi-Bickel syndrome, which is characterised by hepatomegaly and kidney disease; defects in insulin secretion are rare in adult patients, but GLUT2 mutations cause transient neonatal diabetes. Genome-wide association studies have reported that GLUT2 variants increase the risks of fasting hyperglycaemia, transition to type 2 diabetes, hypercholesterolaemia and cardiovascular diseases. Individuals with a missense mutation in GLUT2 show preference for sugar-containing foods. We will discuss how studies in mice help interpret the role of GLUT2 in human physiology. PMID:25421524

Thorens, Bernard

2015-02-01

271

21 CFR 862.1345 - Glucose test system.  

Science.gov (United States)

...Glucose measurements are used in the diagnosis and treatment of carbohydrate metabolism disorders including diabetes mellitus, neonatal hypoglycemia, and idiopathic hypoglycemia, and of pancreatic islet cell carcinoma. (b)...

2010-04-01

272

Brain Glucose Metabolism Controls Hepatic Glucose and Lipid Production  

OpenAIRE

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.

Lam, Tony K. T.

2007-01-01

273

The association between estimated average glucose levels and fasting plasma glucose levels  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE: The level of hemoglobin A1c (HbA1c, also known as glycated hemoglobin, determines how well a patient's blood glucose level has been controlled over the previous 8-12 weeks. HbA1c levels help patients and doctors understand whether a particular diabetes treatment is working and whether adjustments need to be made to the treatment. Because the HbA1c level is a marker of blood glucose for the previous 120 days, average blood glucose levels can be estimated using HbA1c levels. Our aim in the present study was to investigate the relationship between estimated average glucose levels, as calculated by HbA1c levels, and fasting plasma glucose levels. METHODS: The fasting plasma glucose levels of 3891 diabetic patient samples (1497 male, 2394 female were obtained from the laboratory information system used for HbA1c testing by the Department of Internal Medicine at the Izmir Bozyaka Training and Research Hospital in Turkey. These samples were selected from patient samples that had hemoglobin levels between 12 and 16 g/dL. The estimated glucose levels were calculated using the following formula: 28.7 x HbA1c - 46.7. Glucose and HbA1c levels were determined using hexokinase and high performance liquid chromatography (HPLC methods, respectively. RESULTS: A strong positive correlation between fasting plasma glucose levels and estimated average blood glucose levels (r=0.757, p<0.05 was observed. The difference was statistically significant. CONCLUSION: Reporting the estimated average glucose level together with the HbA1c level is believed to assist patients and doctors determine the effectiveness of blood glucose control measures.

Giray Bozkaya

2010-01-01

274

Intestinal glucose metabolism revisited.  

Science.gov (United States)

It is long known that the gut can contribute to the control of glucose homeostasis via its high glucose utilization capacity. Recently, a novel function in intestinal glucose metabolism (gluconeogenesis) was described. The intestine notably contributes to about 20-25% of total endogenous glucose production during fasting. More importantly, intestinal gluconeogenesis is capable of regulating energy homeostasis through a communication with the brain. The periportal neural system senses glucose (produced by intestinal gluconeogenesis) in the portal vein walls, which sends a signal to the brain to modulate hunger sensations and whole body glucose homeostasis. Relating to the mechanism of glucose sensing, the role of the glucose receptor SGLT3 has been strongly suggested. Moreover, dietary proteins mobilize intestinal gluconeogenesis as a mandatory link between their detection in the portal vein and their effect of satiety. In the same manner, dietary soluble fibers exert their anti-obesity and anti-diabetic effects via the induction of intestinal gluconeogenesis. FFAR3 is a key neural receptor involved in the specific sensing of propionate to activate a gut-brain reflex arc triggering the induction of the gut gluconeogenic function. Lastly, intestinal gluconeogenesis might also be involved in the rapid metabolic improvements induced by gastric bypass surgeries of obesity. PMID:24969963

Mithieux, Gilles; Gautier-Stein, Amandine

2014-09-01

275

Continuous glucose monitoring  

OpenAIRE

Continuous glucose monitoring (CGM) technology with its recent development in the real-time feedback has got the potential to revolutionize diabetes care in the near future in the arena of the rapeutic interventions and flexibility in variations in lifestyle or dietary intake. CGM has made the attainment of near-normal blood glucose concentrations, a practical goal for most patients with diabetes.

Pandit, Kaushik

2012-01-01

276

Pre-meal video game playing and a glucose preload suppress food intake in normal weight boys.  

Science.gov (United States)

Increased food intake (FI) during television viewing has been reported in children, but it is unknown if this occurs following pre-meal video game playing (VGP). The objective was to determine the effect of pre-meal VGP for 30?min on subjective appetite and emotions, and FI in normal weight (NW) boys after a glucose or control preload. On four test mornings, NW boys (n?=?19) received equally sweetened preloads of a non-caloric sucralose control or 50?g glucose in 250?mL of water, with or without VGP for 30?min. Food intake from an ad libitum pizza meal was measured immediately after. Subjective appetite was measured at 0, 15, 30, and 60?min. Subjective emotions were determined by visual analog scale at baseline and immediately before lunch. Both VGP (p?=?0.023) and glucose (p?<0.001) suppressed FI. Pre-meal VGP compared with no-VGP, and glucose compared with the non-caloric control, decreased FI by 59 and 170?kcal, respectively. Subjective average appetite increased to 30?min (p?=?0.003), but was lower after glucose (p?=?0.01) in both the VGP and no-VGP conditions compared with the control. Frustration and aggression scores increased after VGP (p?<0.05), but did not correlate with FI. However, baseline and pre-meal happiness and excitement scores were inversely associated with FI. In conclusion, both pre-meal VGP and the glucose preload suppressed FI, supporting the roles of both physiologic and environmental factors in the regulation of short-term FI in 9- to 14-year-old NW boys. PMID:25150911

Branton, Alyson; Akhavan, Tina; Gladanac, Branka; Pollard, Damion; Welch, Jo; Rossiter, Melissa; Bellissimo, Nick

2014-12-01

277

Kidney transplantation improves arterial function measured by pulse wave analysis and endothelium-independent dilatation in uraemic patients despite deterioration of glucose metabolism  

DEFF Research Database (Denmark)

BACKGROUND: The aim of this study is to investigate the effect of kidney transplantation on arterial function in relation to changes in glucose metabolism. METHODS: Included were 40 kidney recipients (Tx group, age 38 ± 13 years) and 40 patients without known diabetes remaining on the waiting list for kidney transplantation (uraemic control group, age 47 ± 11 years). Arterial function was estimated by the pulse wave velocity (PWV) of the carotid-femoral pulse wave, aortic augmentation index (AIX), flow-mediated (FMD) and nitroglycerin-induced vasodilatation (NID) of the brachial artery performed before transplantation and after 12 months. PWV recorded sequentially at the carotid and femoral artery is an estimate of arterial stiffness; AIX is an integrated index of vascular and ventricular function. FMD and NID are the dilatory capacities of the brachial artery after increased flow (endothelium dependent) and after nitroglycerin administration (endothelium independent). The insulin resistance was estimated by the insulin sensitivity index (ISI). RESULTS: AIX was reduced from 27% (17-33) to 14% (7-25) (P = 0.01) after 1 year in the Tx group and remained stable in uraemic controls (P = 0.001, between groups), and NID increased from 11% (7-16) to 18% (12-23) (P = 0.0005). At baseline, carotid-femoral PWV was similar in the Tx group, uraemic controls and healthy controls and it did not change significantly after transplantation. ISI deteriorated in the Tx group from 7.2 ± 4.0 to 5.0 ± 3.0 (P = 0.005) and remained stable in uraemic controls (7.9 ± 5.1 vs 8.5 ± 4.9, NS). Mean arterial blood pressure decreased from 105 ± 13 to 96 ± 11 mmHg (P = 0.005) in the Tx group despite a 20% lower use of antihypertensive agents. CONCLUSIONS: Arterial function measured by AIX and NID was improved 1 year after kidney transplantation. This was associated with a decline in blood pressure and seen inspite of an increase in insulin resistance.

Hornum, Mads; Clausen, Peter

2011-01-01

278

Changes in Glucose Homeostasis after Roux-en-Y Gastric Bypass Surgery for Obesity at Day Three, Two Months, and One Year after Surgery : Role of Gut Peptides  

DEFF Research Database (Denmark)

Context: Endocrine effects of gastric bypass (GBP) surgery for obesity on glucose homeostasis are not fully understood. Main Objective: The main objective of the study was to assess the changes in plasma glucose, insulin, glucagon-like peptide-1 (GLP-1), leptin, somatostatin, glucose-dependent insulinotropic peptide, enteroglucagon, and glucagon early after GBP. Method: Twelve obese subjects (body mass index 45.3 ± 1.9 kg/m2) were subjected to a liquid meal without lipids before and 3 d, 2 months, and 1 yr after GBP. Plasma concentrations of glucose, insulin, leptin, and gut peptide hormones were assessed before and for 180 min after the meal. Satiety was measured with visual analog scales. The absorption rate of acetaminophen added to the liquid meal was measured. Insulin resistance was measured by the homeostasis model assessment of insulin resistance. Results: All subjects lost weight (body mass index 30.3 ± 1.8 kg/m2 at 1 yr). Fasting glucose was significantly lower on d 3 (P < 0.05). There was a progressive decrease in the homeostasis model assessment of insulin resistance after 2 months postoperatively. Postprandially, there was a progressive rise of GLP-1 and enteroglucagon and a transient increase in pancreatic glucagon release over the study period. There was a leftward shift of the time course of plasma glucose and insulin. Somatostatin release was lower on d 3 (P < 0.05) but then unchanged. The absorption rate of acetaminophen was twice as fast after GBP compared with before surgery and did not change over time. Satiety scores increased markedly postoperatively. Conclusion: Both enhanced insulin sensitivity and incretin hormones, such as GLP-1, contribute to the early control of glucose homeostasis. Progressively increasing postprandial levels of enteroglucagon (oxyntomodulin) and GLP-1 facilitate weight loss and enhance insulin effectiveness.

Falkén, Y; Hellström, P M

2011-01-01

279

Identifying Solar Analogs in the Kepler Field  

Science.gov (United States)

Since human beings live on a planet orbiting a G2 V star, to us perhaps the most intrinsically interesting category of stars about which planets have been discovered is solar analogs. While Kepler has observed more than 26000 targets which have effective temperatures within 100K of the Sun, many of these are not true solar analogs due to activity, surface gravity, metallicity, or other considerations. Here we combine ground-based measurements of effective temperature and metallicity with data on rotational periods and surface gravities derived from 16 quarters of Kepler observations to produce a near-complete sample of solar analogs in the Kepler field. We then compare the statistical distribution of stellar physical parameters, including activity level, for subsets of solar analogs consisting of KOIs and those with no detected exoplanets. Finally, we produce a list of potential solar twins in the Kepler field.

Buzasi, Derek L.; Lezcano, Andrew; Preston, Heather L.

2014-06-01

280

The immediate effects of a single bout of aerobic exercise on oral glucose tolerance across the glucose tolerance continuum  

DEFF Research Database (Denmark)

We investigated glucose tolerance and postprandial glucose fluxes immediately after a single bout of aerobic exercise in subjects representing the entire glucose tolerance continuum. Twenty-four men with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or type 2 diabetes (T2D; age: 56 ± 1 years; body mass index: 27.8 ± 0.7 kg/m(2), P > 0.05) underwent a 180-min oral glucose tolerance test (OGTT) combined with constant intravenous infusion of [6,6-(2)H2]glucose and ingestion of [U-(13)C]glucose, following 1 h of exercise (50% of peak aerobic power) or rest. In both trials, plasma glucose concentrations and kinetics, insulin, C-peptide, and glucagon were measured. Rates (mg kg(-1) min(-1)) of glucose appearance from endogenous (RaEndo) and exogenous (oral glucose; Ra OGTT) sources, and glucose disappearance (Rd) were determined. We found that exercise increased RaEndo, RaOGTT, and Rd (all P < 0.0001) in all groups with a tendency for a greater (~20%) peak RaOGTT value in NGT subjects when compared to IGT and T2D subjects. Accordingly, following exercise, the plasma glucose concentration during the OGTT was increased in NGT subjects (P < 0.05), while unchanged in subjects with IGT and T2D. In conclusion, while a single bout of moderate-intensity exercise increased the postprandial glucose response in NGT subjects, glucose tolerance following exercise was preserved in the two hyperglycemic groups. Thus, postprandial plasma glucose responses immediately following exercise are dependent on the underlying degree of glycemic control.

Knudsen, Sine H; Karstoft, Kristian

2014-01-01

281

Mars Analog Site Study (MASS)  

Science.gov (United States)

Many proposed missions to Mars involve landing vehicles, including the Mars 94/96 (Russia), Mars Environmental Survey (MESUR, US), and the Marsnet (ESA) missions. Most landers involve in situ measurements of rock and soil compositions, study of local geology by imaging, and establishment of seismic and meteorological networks. The selection of landing sites on Mars is a complex process that must meet engineering constraints and scientific objectives, using available and anticipated data. The goal of the MASS project is to conduct an 'end-to-end' test of the site selection process using Earth analogs.

Greeley, R.; Kuzmin, R.; Costard, F.; Anderson, F. S.; Geringer, M. A.; Landheim, R.; Wenrich, M. L.

1993-01-01

282

Age- and Gender-Specific Reference Intervals for Fasting Blood Glucose and Lipid Levels in School Children Measured With Abbott Architect c8000 Chemistry Analyzer  

OpenAIRE

Reference intervals for pubertal characteristics are influenced by genetic, geographic, dietary and socioeconomic factors. Therefore, the aim of this study was to establish age-specific reference intervals of glucose and lipid levels among local school children. This was cross-sectional study, conducted among Saudi school children. Fasting blood samples were collected from 2149 children, 1138 (53%) boys and 1011 (47%) girls, aged 6 to 18 years old. Samples were analyzed on the Architect c800...

Tamimi, Waleed; Albanyan, Esam; Altwaijri, Yasmin; Tamim, Hani; Alhussein, Fahad

2012-01-01

283

Liver Fat Content, Evaluated through Semi-Quantitative Ultrasound Measurement, Is Associated with Impaired Glucose Profiles: A Community-Based Study in Chinese  

OpenAIRE

Nonalcoholic fatty liver disease (NAFLD) is closely associated with type 2 diabetes mellitus. We investigated whether the deposition of fat in the liver is associated with glycemic abnormalities and evaluated the contribution of the liver fat content (LFC) to the impaired glucose regulation. We conducted a community-based study among 2836 residents (1018 males and 1818 females) without prior known diabetes mellitus from the Changfeng Study who were at least 45 years old. A standard interview,...

Li, Xiaoming; Xia, Mingfeng; Ma, Hui; Hu, Yu; Yan, Hongmei; He, Wanyuan; Lin, Huandong; Zhao, Naiqing; Gao, Jian; Gao, Xin

2013-01-01

284

Age- and Gender-Specific Reference Intervals for Fasting Blood Glucose and Lipid Levels in School Children Measured With Abbott Architect c8000 Chemistry Analyzer.  

Science.gov (United States)

Reference intervals for pubertal characteristics are influenced by genetic, geographic, dietary and socioeconomic factors. Therefore, the aim of this study was to establish age-specific reference intervals of glucose and lipid levels among local school children. This was cross-sectional study, conducted among Saudi school children. Fasting blood samples were collected from 2149 children, 1138 (53%) boys and 1011 (47%) girls, aged 6 to 18 years old. Samples were analyzed on the Architect c8000 Chemistry System (Abbott Diagnostics, USA) for glucose, cholesterol, triglycerides, HDL and LDL. Reference intervals were established by nonparametric methods between the 2.5th and 97.5th percentiles. Significant differences were observed between boys and girls for cholesterol and triglycerides levels in all age groups (P < 0.02). Only at age 6-7 years and at adolescents, HDL and LDL levels were found to be significant (P < 0.001). No significant differences were seen in glucose levels except at age 12 to 13 years. Saudi children have comparable serum cholesterol levels than their Western counterparts. This may reflect changing dietary habits and increasing affluence in Saudi Arabia. Increased lipid screening is anticipated, and these reference intervals will aid in the early assessment of cardiovascular and diabetes risk in Saudi pediatric populations. PMID:23542765

Tamimi, Waleed; Albanyan, Esam; Altwaijri, Yasmin; Tamim, Hani; Alhussein, Fahad

2012-04-01

285

Radiotracers in the study of marine food chains. The use of compartmental analysis and analog modelling in measuring utilization rates of particulate organic matter by benthic invertebrates  

International Nuclear Information System (INIS)

The present study assesses the problem of recycling when using radiotracers to quantify ingestion and assimilation rates of particulate organic matter by benthic invertebrates. The rapid production of dissolved organic matter and its subsequent utilization by benthic invertebrates constitutes a major bias in this kind of study. However recycling processes may also concern POM through the production and reingestion of faeces. The present paper shows that compartmental analysis of the diffusion kinetics of the radiotracer between the different compartments of the system studied and the analog modelling of the exchanges of radioactivity between compartments may be used in order to determine ingestion and assimilation rates. This method is illustrated by the study of a system composed of the bacteria Lactobacillus sp. and the filter-feeding bivalve Venerupis decussata. The advantages and drawbacks of this approach relative to other existing methods are briefly discussed. (Author)

286

Isotopic estimation of plasma glucose conversion to plasma lactate using [6-3H]glucose and [6-14C]glucose.  

Science.gov (United States)

To determine whether [6-3H]glucose could be used to quantitatively estimate the rate of plasma glucose conversion to plasma lactate, we compared the relative transfer of [3H] and [14C]plasma glucose to plasma lactate in nine postabsorptive anesthetized rats infused to isotopic steady state with [6-3H]glucose and [6-14C]glucose. Glucose turnover (mumol/kg/min) measured with [6-3H]glucose (29.4 +/- 1.7) and [6-14C]glucose (25.0 +/- 1.5), Cori cycle activity (4.35 +/- 0.79), and the percentage of plasma lactate derived from plasma glucose calculated from 14C-specific activities (59.8 +/- 5.8) were all comparable to previously reported values for the overnight fasted rat. Although the percentage of plasma lactate derived from plasma glucose calculated from 3H-specific activities (30.0 +/- 3.3) was only half that calculated from 14C-specific activities (P less than 0.001), the 3H:14C ratios were constant over a wide range of percentage of lactate derived from glucose (r = 0.95, P less than 0.001). We conclude that 3H-specific activity ratios of plasma lactate to plasma glucose cannot be directly used as a quantitative estimate of the percentage of plasma lactate derived from plasma glucose; however, correction for the apparent constant proportionality of detritiation of lactate relative to 14C loss could permit use of [6-3H]glucose for this purpose. PMID:2798436

Nurjhan, N; Consoli, A; Gerich, J

1989-10-01

287

Analog signal isolation techniques  

International Nuclear Information System (INIS)

This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application

288

Towards analogy in toponyms.  

Czech Academy of Sciences Publication Activity Database

Cluj : Mega, 2013 - (Felecan, O.), s. 379-383 ISBN 978-606-543-343-4. [Name and Naming /2./ Onomastics in Contemporary Public Space. Baia Mare (RO), 09.05.2013-11.05.2013] R&D Projects: GA ?R GPP406/12/P600 Institutional support: RVO:68378092 Keywords : onomastics * toponyms * analogy Subject RIV: AI - Linguistics

Št?pán, Pavel

289

Quantum Analog Computing  

Science.gov (United States)

Quantum analog computing is based upon similarity between mathematical formalism of quantum mechanics and phenomena to be computed. It exploits a dynamical convergence of several competing phenomena to an attractor which can represent an externum of a function, an image, a solution to a system of ODE, or a stochastic process.

Zak, M.

1998-01-01

290

14C-glucose binding assay of the glucose transporter binding sites in muscular cell membrane  

International Nuclear Information System (INIS)

A method of determining the binding sites of glucose transporter in rat muscular cell membrane was introduced. The crude products of cell membrane form the skeletal muscle of control and insulin treated rats were prepared, and then fractionated in sucrose gradient. Both plasma membrane and microsome membrane were incubated with D-[U-14C] glucose respectively for the measurement of radioactivity and Scatchard plot analysis. It was found that the binding sites of glucose transporter in plasma membrane and intracellular membrane were 5.6 nmol 14C-glucose/mg protein and 8.7 nmol 14C-glucose-mg protein respectively at basic state. Insulin treatment in experimental groups caused approximately 146% increase in plasma membrane fraction and 88% decrease in intracellular membrane fraction. Moreover, the kinetic data of Scatchard plot curve were similar to those of the [3H]-cytochalasin B binding assay. D-[U-14C] glucose binding assay of glucose transporter binding sites in muscular cell membrane is simple, easy and practicable. The D-[U-14C] glucose is commercially available

291

Chemosensitizing and cytotoxic effects of 2-deoxy-D-glucose on breast cancer cells  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Accelerated glucose uptake for anerobic glycolysis is one of the major metabolic changes found in malignant cells. This property has been exploited for imaging malignancies and as a possible anticancer therapy. The nonmetabolizable glucose analog 2-deoxyglucose (2?DG interferes with glucose metabolism leading to breast cancer cell death. Aims: To determine whether 2DG can synergize with chemotherapeutic agents commonly used in breast cancer treatment and identify cellular characteristics associated with sensitivity to 2DG. Materials and Methods: SkBr3 breast cancer cells were incubated with varying concentrations of 5-fluorouracil (5FU, doxorubicin, cisplatin, cyclophosphamide, or herceptin with or without 2DG. Cell viability was measured using the MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay. Results: Combining 2DG with doxorubicin, 5?FU, cyclophosphamide, and herceptin resulted in enhanced cell death compared with each agent alone, while in combination with cisplatin, the amount of cell death was additive. Mouse embryo fibroblasts (MEF mutated for p53 (-/- were 30% more sensitive to the cytotoxic effects of 2DG than the parental cell lines. Cells mutated for Bax/Bac, genes involved in protection from apoptosis, are slightly more sensitive than the parental cell lines. Conclusions: These results indicate that 2DG acts synergistically with specific chemotherapeutic agents in causing cell death and the class of chemicals most sensitive appear to be those which cause DNA damage.

Zhang Fanjie

2009-09-01

292

Walking Speed and Brain Glucose Uptake are Uncoupled in Patients with Multiple Sclerosis  

Science.gov (United States)

Motor impairments of the upper and lower extremities are common symptoms of multiple sclerosis (MS). While some peripheral effects like muscle weakness and loss of balance have been shown to influence these symptoms, central nervous system activity has not been fully elucidated. The purpose of this study was to determine if alterations in glucose uptake were associated with motor impairments in patients with multiple sclerosis. Eight patients with multiple sclerosis (four men) and eight sex matched healthy controls performed 15?min of treadmill walking at a self-selected pace, during which ?322?MBq of the positron emission tomography (PET) glucose analog [18F]-fluorodeoxyglucose (FDG) was injected. Immediately after the cessation of walking, participants underwent PET imaging. Patients with MS had lower FDG uptake in ?40% of the brain compared to the healthy controls (pFWE-corr???0.75, P?glucose metabolism. Understanding how brain activity and metabolism are altered in patients with MS may allow for better measures of disability and disease status within this clinical population. PMID:25741275

Kindred, John H.; Tuulari, Jetro J.; Bucci, Marco; Kalliokoski, Kari K.; Rudroff, Thorsten

2015-01-01

293

Human adipocyte glucose transport system. Biochemical and functional heterogeneity of hexose carriers.  

OpenAIRE

We have investigated glucose transport proteins in isolated human adipocytes. Using the cytochalasin B binding assay to measure glucose transporters in subcellular membrane subfractions, we found that insulin induced translocation of intracellular glucose transporters to the cell surface. Isoelectric focusing of glucose transporters photolabeled with [3H]cytochalasin B revealed two distinct glucose transporter isoforms in low density microsomes focusing at pH 5.6 and pH 6.4, but only the pH 5...

Matthaei, S.; Garvey, W. T.; Horuk, R.; Hueckstaedt, T. P.; Olefsky, J. M.

1987-01-01

294

Patient-specific Glucose Metabolism Models for Model Predictive Control of T1DM Glycemia  

OpenAIRE

The development of a predictive control algorithm for glycaemia regulation in diabetic subjects requires patient-specific models of the glucose metabolism which are physiologically relevant, parsimonious, yet able to accurately forecast blood glucose. Given the measured data: total plasma insulin mIU/L; plasma glucose mg/dL; plasma glucose rate of appearance after intestinal absorption mg/kg/min, the objective was to find individualized, simple and plausible glucose-insulin interaction...

Cescon, Marzia; Johansson, Rolf

2012-01-01

295

Hydration dynamics of aqueous glucose probed with polarization-resolved fs-IR spectroscopy.  

Science.gov (United States)

The dynamics of water in aqueous solutions of glucose have been investigated using polarization-resolved femtosecond infrared spectroscopy of the hydroxyl stretch vibrations of water and glucose. Using reference measurements on solutions of glucose in dimethylsulfoxide and a spectral decomposition model, we are able to distinguish the reorientation dynamics of the glucose and water hydroxyl groups. We find that the water reorientation dynamics strongly slow down in the presence of glucose. PMID:24952548

Groot, C C M; Bakker, H J

2014-06-21

296

Unlocking the potential of continuous glucose monitoring: a new guideline supports the development of continuous glucose monitoring devices.  

Science.gov (United States)

Continuous glucose monitoring (CGM) is a new technology that allows patients to measure glucose levels continuously over several days. It has several advantages over traditional glucose meters in that it does not involve repeated finger sticks and can measure trends and track changes in glucose levels over time. The Clinical and Laboratory Standards Institute, working with the Diabetes Technology Society, published Performance Metrics for Continuous Interstitial Glucose Monitoring; Approved Guideline, which provides recommendations for methods for determining analytical and clinical metrics of CGMs. The document provides guidance on how CGM data should be presented, compared between devices, and compared between measurement technologies. The document serves as a roadmap for the testing of CGM devices and will ultimately advance the potential of this exciting technology. Performance Metrics for Continuous Interstitial Glucose Monitoring; Approved Guideline represents the consensus view on preparing and presenting CGM data. PMID:20144368

D'Archangelo, Melissa J

2009-03-01

297

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose ... Support Legal Assistance Success Stories Complications Hypoglycemia Hyperglycemia Skin Complications Eye Complications Neuropathy Foot Complications DKA (Ketoacidosis) & ...

298

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral ... 2 Diabetes Know Your Rights Employment Discrimination Health Care Professionals Law Enforcement Driver's License For Lawyers Food & ...

299

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Non-starchy Vegetables Grains and Starchy Vegetables Fats Alcohol What Can I Drink? Fruit Dairy Food Tips ... may make your blood glucose level go even higher. You'll need to work with your doctor ...

300

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day Diabetes Basics ... Advocacy Easy Advocacy Checklists for Association Events Messaging Tools Recruiting Advocates Local Market Planning Training Webinars News & ...

301

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy 8 Tips for Caregivers Health Insurance Health Insurance Update The ...

302

All about Blood Glucose  

Science.gov (United States)

What are the blood glucose targets for people with diabetes? TargetssetbytheAmerican DiabetesAssociation (ADA)arelistedbelow. Talkwithyourhealthcareteam aboutyour personalgoals. What’s the best way to keep track of ...

303

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... ketones, do not exercise. Exercising when ketones are present may make your blood glucose level go even ... decide what to do next. Fully revised and updated, this is the "take-you-by-the-hand" ...

304

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Mental Health Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin ... Diabetes Pro: Professional Resources Online We Support Your Doctor Clinical Practice Guidelines Patient Education Materials Scientific Sessions ...

305

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Superfoods Non-starchy Vegetables Grains and Starchy Vegetables Fats Alcohol What Can I Drink? Fruit Dairy Food ... glucose for fuel, so your body breaks down fats to use for energy. When your body breaks ...

306

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor ... Non-starchy Vegetables Grains and Starchy Vegetables Fats Alcohol What Can I Drink? Fruit Dairy Food Tips ...

307

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor ... Information and Community Support Legal Assistance Success Stories Complications Hypoglycemia Hyperglycemia Skin Complications Eye Complications Neuropathy Foot ...

308

Insulin Induces an Increase in Cytosolic Glucose Levels in 3T3-L1 Cells with Inhibited Glycogen Synthase Activation  

OpenAIRE

Glucose is an important source of energy for mammalian cells and enters the cytosol via glucose transporters. It has been thought for a long time that glucose entering the cytosol is swiftly phosphorylated in most cell types; hence the levels of free glucose are very low, beyond the detection level. However, the introduction of new fluorescence resonance energy transfer-based glucose nanosensors has made it possible to measure intracellular glucose more accurately. Here, we used the fluoresce...

Chowdhury, Helena H.; Marko Kreft; Jørgen Jensen; Robert Zorec

2014-01-01

309

Mathematical Modeling of Renal Tubular Glucose Absorption after Glucose Load  

OpenAIRE

A partial differential Progressive Tubular Reabsorption (PTR) model, describing renal tubular glucose reabsorption and urinary glucose excretion following a glucose load perturbation, is proposed and fitted to experimental data from five subjects. For each subject the Glomerular Filtration Rate was estimated and both blood and urine glucose were sampled following an Intra-Venous glucose bolus. The PTR model was compared with a model representing the conventional Renal Threshold Hypothesis (RT...

Gaetano, Andrea; Panunzi, Simona; Eliopoulos, Dimitris; Hardy, Thomas; Mingrone, Geltrude

2014-01-01

310

Abnormal temporal lobe response in Alzheimer's disease during cognitive processing as measured by 11C-2-deoxy-D-glucose and PET  

International Nuclear Information System (INIS)

Elderly controls and probable Alzheimer's disease patients underwent serial positron emission tomography (PET) studies during a baseline condition and while performing a verbal memory task. For the temporal lobes, all 7 Alzheimer patients demonstrated a relative shift in glucose metabolic rates to the right hemisphere during the memory condition relative to baseline, and 5 of 7 controls showed a shift to the left hemisphere. Baseline absolute regional metabolic rates replicate previous findings and were somewhat less useful than the memory challenge in differentiating patients from controls. These results indicate that a temporal lobe abnormality in Alzheimer's disease is related to memory performance

311

Utility of accurate monoisotopic mass measurements to confidently identify lambda exonuclease generated single-stranded amplicons containing 7-deaza analogs by electrospray ionization FT-ICR mass spectrometry  

Science.gov (United States)

A 53-base pair region on the long arm of chromosome 22 was amplified using PCR with 7-deaza-modified deoxynucleotides. Increased amplification efficiency was achieved by doubling the concentration of the modified deoxynucleotide triphosphates. Incorporation of 7-deaza purines has been previously shown to selectively eliminate fragmentation pathways during gas-phase sequencing of nucleic acids by sustained off-resonance irradiation collision-induced dissociation (SORI-CID) and infrared multiphoton dissociation. However, 7-deaza analogs result in significant duplex stability precluding interrogation of the single-stranded species by tandem mass spectrometry. Herein, we demonstrate the use of lambda exonuclease to successfully overcome this problem and are able to obtain single-stranded PCR products containing 7-deaza adenine and guanine nucleobases. Mass accuracy was used as our metric to determine complete incorporation of 7-deaza residues in PCR products>15 kDa; PCR products were fragmented using SORI-CID and as expected, cleavage at the 7-deaza modified sites was not observed. Collectively, this integrated approach can facilitate top-down sequencing of PCR products by a variety of tandem mass spectrometry methods.

Frahm, Jennifer L.; Mason, Christopher J.; Muddiman, David C.

2004-05-01

312

Funcionamento diferencial dos itens (DIF): estudo com analogias para medir o raciocínio verbal / Differential items functioning (DIF): study with analogies for measurement the verbal reasoning  

Scientific Electronic Library Online (English)

Full Text Available Este estudo objetivou determinar o funcionamento diferencial de 30 analogias destinadas à avaliação do raciocínio verbal, considerando a variável sexo. Utilizou-se uma amostra de 730 alunos do Ensino Médio, com idade média de 17,74 anos (dp= 3,12 anos). A maioria procedia de escolas públicas (58,5%) [...] e era do sexo feminino (53,2%). Os grupos organizados para a investigação foram compostos por homens (n=342) e mulheres (n=388). Os parâmetros métricos dos itens foram determinados pelo modelo TRI de dois parâmetros logísticos. Para a verificação do DIF foram comparados os parâmetros métricos dos itens. Os resultados indicaram a presença de cinco itens com DIF. Abstract in english This research aimed the determination of the differential item functioning (DIF) in 30 analogies used for the verbal reasoning assessment in students, taking into account the sex variable. A sample of 730 high school students, whose average age was 17,74 years (sd = 3,12 years) was used. The majorit [...] y was composed by students from public schools (58,4%) and females (53,3%). The groups which participated in the study of DIF were composed by men (n= 342) and women (n= 388). The metric parameters of the items were determined according to the TRI model of two logistics parameters. For the determination of the DIF the method of comparation of the metric parameters of the items was used. The results indicated the presence of five items with DIF.

Wagner Bandeira, Andriola.

313

Analog storage integrated circuit  

Science.gov (United States)

A high speed data storage array is defined utilizing a unique cell design for high speed sampling of a rapidly changing signal. Each cell of the array includes two input gates between the signal input and a storage capacitor. The gates are controlled by a high speed row clock and low speed column clock so that the instantaneous analog value of the signal is only sampled and stored by each cell on coincidence of the two clocks. 6 figs.

Walker, J.T.; Larsen, R.S.; Shapiro, S.L.

1989-03-07

314

On probabilistic analog automata  

OpenAIRE

We consider probabilistic automata on a general state space and study their computational power. The model is based on the concept of language recognition by probabilistic automata due to Rabin and models of analog computation in a noisy environment suggested by Maass and Orponen, and Maass and Sontag. Our main result is a generalization of Rabin's reduction theorem that implies that under very mild conditions, the computational power of the automaton is limited to regular l...

Ben-hur, A.; Roitershtein, A.; Siegelmann, H.

2003-01-01

315

Genetic Algorithm Tuning of PID Controller in Smith Predictor for Glucose Concentration Control  

OpenAIRE

This paper focuses on design of a glucose concentration control system based on nonlinear model plant of E. coli MC4110 fed-batch cultivation process. Due to significant time delay in real time glucose concentration measurement, a correction is proposed in glucose concentration measurement and a Smith predictor (SP) control structure based on universal PID controller is designed. To reduce the influence of model error in SP structure the estimate of measured glucose concentration is used. For...

Tsonyo Slavov; Olympia Roeva

2011-01-01

316

Microbiosensors for acetylcholine and glucose.  

Science.gov (United States)

Microbiosensors based on carbon and and platinum fibers are described. Carbon fibers were used to construct microelectrodes of 7 microm diameter. Electrochemical operations for pre-electrolysis and measuring were examined for the highly sensitive determination of hydrogen peroxide. A triangular potential (-2 to +2V vs Ag/AgCl) was applied before measuring each pair of double pulses (first pulse: 750 mV; second pulse: 1100 mV). The determination limit was 0.1 microM of hydrogen peroxide. The reproducible determination of hydrogen peroxide is possible even in samples containing albumin protein. The separation of hydrogen peroxide from ascorbic acid is also possible because the oxidation potential of ascorbic acid is different from that of hydrogen peroxide. An acetylcholine microsensor was fabricated by immobilizing acetylcholine esterase and choline oxidase on the carbon fiber by entrapment with poly(vinyl alcohol)-quarternized stilbazole (PVA-SbQ). This sensor gave a linear calibration plot for the range 0.1-1.0 mM with a linear correlation coefficient of 0.9842. Glucose oxidase (GOD) and glucose dehydrogenase (GDH) immobilized cylindrical platinum microelectrodes were fabricated, and their characteristics were evaluated, respectively, by using 1,4-benzoquinone (BQ) and ferricyanide as electron mediators. Each enzyme was immobilized by using PVA-SbQ on a cylindrical microelectrode of 2 microm diameter. A linear range in the calibration curve of the GOD-based glucose microsensor was observed to be wider than that obtained using a disk electrode of 1 mm diameter. The mediated response of the 2 microm glucose sensor was compared with the response resulting from hydrogen peroxide detection. This result showed that a higher response and a wider linear range were observed with highly concentrated mediator. A much higher response of the GDH immobilized 2 microm microelectrode was obtained when not only ferricyanide but also diaphorase was employed to reoxidize the NADH produced by the enzyme reaction of GDH. The GHD-based glucose microsensor was found to be unaffected by the concentration of dissolved oxygen. PMID:8357577

Karube, I; Yokoyama, K; Tamiya, E

1993-01-01

317

Spatial relationship between tumor perfusion and endogeneous glucose distribution  

International Nuclear Information System (INIS)

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 expeucose (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 vessels

318

Oxytocin increases extrapancreatic glucagon secretion and glucose production in pancreatectomized dogs  

International Nuclear Information System (INIS)

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 [6-3H]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 ?U/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

319

Oxytocin increases extrapancreatic glucagon secretion and glucose production in pancreatectomized dogs  

Energy Technology Data Exchange (ETDEWEB)

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-/sup 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 ..mu..U/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.

Altszuler, N.; Puma, F.; Winkler, B.; Fontan, N.; Saudek, C.D.

1986-05-01

320

Towards Analog Reverse Time Computation  

CERN Document Server

We report the consequences of a destabilization process on a simulated General Purpose Analog Computer. This new technology overcomes problems linked with serial ambiguity, and provides an analog bias to encode algorithms whose complexity is over polynomial. We also implicitly demonstrate how countermesures of the Stochastic Aperture Degeneracy could efficiently reach higher computational classes, and would open a road towards Analog Reverse Time Computation.

Habibi, O; Dhar, M O

2006-01-01

321

D-glucose- and D-mannose-based antimetabolites. Part 2. Facile synthesis of 2-deoxy-2-halo-D-glucoses and -D-mannoses.  

Science.gov (United States)

Modified D-glucose and D-mannose analogs are potentially clinically useful metabolic inhibitors. Biological evaluation of 2-deoxy-2-halo analogs has been impaired by limited availability and lack of efficient methods for their preparation. We have developed practical synthetic approaches to 2-deoxy-2-fluoro-, 2-chloro-2-deoxy-, 2-bromo-2-deoxy-, and 2-deoxy-2-iodo derivatives of D-glucose and D-mannose that exploit electrophilic addition reactions to a commercially available 3,4,6-tri-O-acetyl-D-glucal. PMID:19625015

Fokt, Izabela; Szymanski, Slawomir; Skora, Stanislaw; Cybulski, Marcin; Madden, Timothy; Priebe, Waldemar

2009-08-17

322

Variable Classifications of Glycemic Index Determined by Glucose Meters  

OpenAIRE

The study evaluated and compared the differences of glucose responses, incremental area under curve (IAUC), glycemic index (GI) and the classification of GI values between measured by biochemical analyzer (Fuji automatic biochemistry analyzer (FAA)) and three glucose meters: Accue Chek Advantage (AGM), BREEZE 2 (BGM), and Optimum Xceed (OGM). Ten healthy subjects were recruited for the study. The results showed OGM yield highest postprandial glucose responses of 119.6 ± 1.5, followed by FA...

Lin, Meng-hsueh Amanda; Wu, Ming-chang; Lin, Jenshinn

2010-01-01

323

High glucose impairs superoxide production from isolated blood neutrophils  

DEFF Research Database (Denmark)

Superoxide (O(2)(-)), a key antimicrobial agent in phagocytes, is produced by the activity of NADPH oxidase. High glucose concentrations may, however, impair the production of O(2)(-) through inhibition of glucose-6-phosphate dehydrogenase (G6PD), which catalyzes the formation of NADPH. This study measured the acute effects of high glucose or the G6PD inhibitor dehydroepiandrosterone (DHEA) on the production of O(2)(-) from isolated human neutrophils.

Perner, A; Nielsen, S E

2003-01-01

324

Reliability, Responsiveness, and Validity of the Visual Analog Fatigue Scale to Measure Exertion Fatigue in People with Chronic Stroke: A Preliminary Study  

Science.gov (United States)

Background and Purpose. Post-Stroke Fatigue (PSF) is a prevalent yet commonly neglected issue that impacts daily functions and quality of life in people post-stroke. To date no studies have attempted to validate a clinically-feasible and reliable instrument to quantify PSF. We developed the Visual Analog Fatigue Scale (VAFS) to eliminate difficulties and poor data validity in testing people post-stroke. The purpose of this study was to evaluate the reliability, responsiveness, and validity of the VAFS. Methods. Twenty-one people post-stroke (12 males, age? = 59.5 ± 10.3 years; time post-stroke? = 4.1 ± 3.5 years) participated. Subjects underwent a standardized fatigue-inducing exercise; fatigue level was assessed at rest, immediately after exercise, and after recovery. The same protocol was repeated after 14 days. Results. ICC values for the VAFS at rest was 0.851 (CI?=?95%, 0.673???0.936, P < .001), immediately after exercise was 0.846 (CI?=?95%, 0.663???0.934, P < .001), and 15 minutes after exercise was 0.888 (CI?=?95%, 0.749???0.953, P < .001). The ES values for at-rest to post-exercise and for post-exercise to post-recovery were 14.512 and 0.685, respectively. Using paired t-test, significant difference was found between VAFS scores at-rest and post-exercise (P < .001), and between post-exercise and post-recovery (P < .001). Conclusion. Our data suggests good reliability, responsiveness, and validity of the VAFS to assess exertion fatigue in people post-stroke. PMID:20700421

Tseng, Benjamin Y.; Gajewski, Byron J.; Kluding, Patricia M.

2010-01-01

325

Acetaminophen glucuronide and plasma glucose report identical estimates of gluconeogenesis and glycogenolysis for healthy and prediabetic subjects using the deuterated water method.  

Science.gov (United States)

Plasma glucose (2) H-enrichment in positions 5 ((2) H5) and 2 ((2) H2) from deuterated water ((2) H2 O) provides a measure of the gluconeogenic contribution to endogenous glucose production. Urinary glucuronide analysis can circumvent blood sampling but it is not known if glucuronide and glucose enrichments are equal. Thirteen subjects with impaired fasting glucose/impaired glucose tolerance and 11 subjects with normal fasting glucose and normal glucose tolerance ingested (2) H2 O to ?0.5% body water and acetaminophen. Glucose and glucuronide (2) H5 and (2) H2 were measured by (2) H NMR spectroscopy of monoacetone glucose. For normal fasting glucose/normal glucose tolerance, (2) H5 was 0.23 ± 0.02% and 0.25 ± 0.02% for glucose and glucuronide, respectively, whereas (2) H2 was 0.47 ± 0.01% and 0.49 ± 0.02%, respectively. For impaired fasting glucose/impaired glucose tolerance, (2) H5 was 0.22 ± 0.01% and 0.26 ± 0.02% for glucose and glucuronide, respectively, whereas (2) H2 was 0.46 ± 0.01% and 0.49 ± 0.02%, respectively. The gluconeogenic contribution to endogenous glucose production measured from glucose and glucuronide were identical for both normal fasting glucose/normal glucose tolerance (48 ± 4 vs. 51 ± 3%) and impaired fasting glucose/impaired glucose tolerance (48 ± 2 vs. 53 ± 3%). PMID:23023691

Barosa, Cristina; Jones, John G; Rizza, Robert; Basu, Ananda; Basu, Rita

2013-08-01

326

ESD analog circuits and design  

CERN Document Server

A comprehensive and in-depth review of analog circuit layout, schematic architecture, device, power network and ESD design This book will provide a balanced overview of analog circuit design layout, analog circuit schematic development, architecture of chips, and ESD design.  It will start at an introductory level and will bring the reader right up to the state-of-the-art. Two critical design aspects for analog and power integrated circuits are combined. The first design aspect covers analog circuit design techniques to achieve the desired circuit performance. The second and main aspect pres

Voldman, Steven H

2014-01-01

327

Planning a site investigation using analogous groups  

International Nuclear Information System (INIS)

A limited field investigation (LFI) has been designed for the 200-UP-2 Operable Unit within the 200 Areas of the US Department of Energy (DOE) Hanford Site in Washington state using the concept of analogous groups. The LFI is part of a RCRA facility investigation (RFI) corrective measures study (CMS) being conducted in this operable unit. The concept emphasizes that characterization activities can be reduced by identifying select sites (analogous sites) for characterization that represents a group of sites (analogous groups). This concept is particularly applicable to operable units that contain several waste management units that are similar in design, disposal history, and geology. Application of this concept reduced the number of waste management units initially undergoing characterization by more than two-thirds. The work plan is presently in the approval cycle with the field characterization phase expected to begin August 1993

328

Planning a site investigation using analogous groups  

Energy Technology Data Exchange (ETDEWEB)

A limited field investigation (LFI) has been designed for the 200-UP-2 Operable Unit within the 200 Areas of the US Department of Energy (DOE) Hanford Site in Washington state using the concept of analogous groups. The LFI is part of a RCRA facility investigation (RFI) corrective measures study (CMS) being conducted in this operable unit. The concept emphasizes that characterization activities can be reduced by identifying select sites (analogous sites) for characterization that represents a group of sites (analogous groups). This concept is particularly applicable to operable units that contain several waste management units that are similar in design, disposal history, and geology. Application of this concept reduced the number of waste management units initially undergoing characterization by more than two-thirds. The work plan is presently in the approval cycle with the field characterization phase expected to begin August 1993.

Pak, P.M. [USDOE Richland Operations Office, WA (United States); Galgoul, M.J.; Wittreich, C.D. [Westinghouse Hanford Co., Richland, WA (United States)

1993-09-01

329

Interaction of Glucose with ZnO Nanoparticles  

Directory of Open Access Journals (Sweden)

Full Text Available We report the results of the extent of interaction as well as the formation of a bioconjugate of glucose with Zinc Oxide nano particles (ZnO NPs to understand the non-invasive monitoring of glucose by semiconductor NPs. We performed an array of photophysical as well as microscopic measurements to quantify the interaction between ZnO NPs and glucose. We have found that time constant of interaction (t1 ? 18.47 min for the binding glucose with surface of ZnO NPs and follows a single exponential association process.

P.K. Samanta

2014-06-01

330

Nonoxidative Glucose Consumption during Focal Physiologic Neural Activity  

Science.gov (United States)

Brain glucose uptake, oxygen metabolism, and blood flow in humans were measured with positron emission tomography, and a resting-state molar ratio of oxygen to glucose consumption of 4.1:1 was obtained. Physiological neural activity, however, increased glucose uptake and blood flow much more (51 and 50 percent, respectively) than oxygen consumption (5 percent) and produced a molar ratio for the increases of 0.4:1. Transient increases in neural activity cause a tissue uptake of glucose in excess of that consumed by oxidative metabolism, acutely consume much less energy than previously believed, and regulate local blood flow for purposes other than oxidative metabolism.

Fox, Peter T.; Raichle, Marcus E.; Mintun, Mark A.; Dence, Carmen

1988-07-01

331

Pancreatic islets of variable size - insulin secretion and glucose utilization  

International Nuclear Information System (INIS)

Glucose metabolism and insulin secretion were studied in isolated rat pacreatic islets of different sizes and the amount of tissue was quantitated by the measurement of DNA. It was found that larger islets (140-210 ng DNA/islet) utilized more glucose (based on the conversion of 3H-5-glucose to 3H2O) per ng of DNA than islets containing less DNA (60-120 ng/islet). However, the insulin secreted per ng of DNA in response to a given glucose concentration was the same in islets of all sizes. Also, the islet insulin and glucagon content when expressed in terms of DNA did not depend upon islet size. Thus, although glucose utilization rates expressed as a function of islet DNA content were greater in larger islets, no such relationship was found for glucose-induced insulin release or insulin and glucagon content. 17 reference, 1 figure, 3 tables

332

Procurement of radioiodinated glucose derivative and its biological character  

International Nuclear Information System (INIS)

A glucose derivative substituted at the C-2 position by a p-iodobenzyl group, a 2-0-(p-iodobenzyl)-D-glucose (IBG) was designed and its synthesis was carried out. [125I]IBG was obtained by radioisotopic exchange reaction with high radiochemical purity and radiochemical yield, requiring no purification. The good in vivo and in vitro stability and the chemical and biological characteristic displayed by the new [125I]IBG stimulated the measurement of the brain uptake index (BUI). In the presence of glucose, brain uptake inhibition was detected, a good indication of a glucose carrier mediator for the transport of [125I]IBG through the blood-brain barrier,a similar feature to that of [14C]glucose or 3-0-[14C]methylglucose. The newly designed ligand IBG holds good promise for the study of regional cerebral glucose utilization, should the 123I become available. (author)

333

Noninvasive blood glucose monitoring with laser diode  

Science.gov (United States)

The non-invasive measurement of blood sugar level was studied by use of near infrared laser diodes. The in vitro and in vivo experiments were carried out using six laser diodes having wavelengths range from 1550 nm to 1750nm. Several volunteers were tested for OGTT (Oral Glucose Tolerance Test) experiment. We took blood from a fingertip and measured its concentration with a glucose meter while taking signal voltage from laser diodes system. The data of signal voltage were processed to do calibration and prediction; in this paper PLS (Partial Least Square) method was used to do modeling. For in vitro experiment, good linear relationship between predicted glucose concentration and real glucose concentration was obtained. For in vivo experiments, we got the blood sugar level distributions in Clarke error grid that is a reference for doctors to do diagnosis and treatment. In the Clarke error grid, 75% of all data was in area A and 25 % was in area B. From the in vitro and in vivo results we know that multiple laser diodes are suitable for non-invasive blood glucose monitoring.

Zhang, Xiqin; Chen, Jianhong; Ooi, Ean Tat; Yeo, Joon Hock

2006-02-01

334

Glucose-6-phosphatase deficiency  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Glucose-6-phosphatase deficiency (G6P deficiency, or glycogen storage disease type I (GSDI, is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, between the ages of 3 to 4 months by symptoms of hypoglycemia (tremors, seizures, cyanosis, apnea. Patients have poor tolerance to fasting, marked hepatomegaly, growth retardation (small stature and delayed puberty, generally improved by an appropriate diet, osteopenia and sometimes osteoporosis, full-cheeked round face, enlarged kydneys and platelet dysfunctions leading to frequent epistaxis. In addition, in GSDIb, neutropenia and neutrophil dysfunction are responsible for tendency towards infections, relapsing aphtous gingivostomatitis, and inflammatory bowel disease. Late complications are hepatic (adenomas with rare but possible transformation into hepatocarcinoma and renal (glomerular hyperfiltration leading to proteinuria and sometimes to renal insufficiency. GSDI is caused by a dysfunction in the G6P system, a key step in the regulation of glycemia. The deficit concerns the catalytic subunit G6P-alpha (type Ia which is restricted to expression in the liver, kidney and intestine, or the ubiquitously expressed G6P transporter (type Ib. Mutations in the genes G6PC (17q21 and SLC37A4 (11q23 respectively cause GSDIa and Ib. Many mutations have been identified in both genes,. Transmission is autosomal recessive. Diagnosis is based on clinical presentation, on abnormal basal values and absence of hyperglycemic response to glucagon. It can be confirmed by demonstrating a deficient activity of a G6P system component in a liver biopsy. To date, the diagnosis is most commonly confirmed by G6PC (GSDIa or SLC37A4 (GSDIb gene analysis, and the indications of liver biopsy to measure G6P activity are getting rarer and rarer. Differential diagnoses include the other GSDs, in particular type III (see this term. However, in GSDIII, glycemia and lactacidemia are high after a meal and low after a fast period (often with a later occurrence than that of type I. Primary liver tumors and Pepper syndrome (hepatic metastases of neuroblastoma may be evoked but are easily ruled out through clinical and ultrasound data. Antenatal diagnosis is possible through molecular analysis of amniocytes or chorionic villous cells. Pre-implantatory genetic diagnosis may also be discussed. Genetic counseling should be offered to patients and their families. The dietary treatment aims at avoiding hypoglycemia (frequent meals, nocturnal enteral feeding through a nasogastric tube, and later oral addition of uncooked starch and acidosis (restricted fructose and galactose intake. Liver transplantation, performed on the basis of poor metabolic control and/or hepatocarcinoma, corrects hypoglycemia, but renal involvement may continue to progress and neutropenia is not always corrected in type Ib. Kidney transplantation can be performed in case of severe renal insufficiency. Combined liver-kidney grafts have been performed in a few cases. Prognosis is usually good: late hepatic and renal complications may occur, however, with adapted management, patients have almost normal life span. Disease name and synonyms Glucose-6-phosphatase deficiency or G6P deficiency or glycogen storage disease type I or GSDI or type I glycogenosis or Von Gierke disease or Hepatorenal glycogenosis.

Labrune Philippe

2011-05-01

335

PACS with analog (video) inputs  

International Nuclear Information System (INIS)

Until ACR-NEMA standards are widely accepted, picture achieving and communications system (PACS) must use analog (video) input of image data from Mr and CT scanners. This paper investigates the dynamic range of data so stored and acquired, compared with conventional film. Representative MR and CT images of the brain and body were transferred by video signal both to a prototype PACS system (CommView, AT and T) and to a laser imager (3M). Quantitative measurement of output optical density versus original video input for the two systems were compared. For average widow and level settings, images from the laser imager possessed a greater dynamic range (gamma characteristic) that those from the PACS system

336

Metastatic insulinoma managed with radiolabeled somatostatin analog.  

Science.gov (United States)

Insulinoma is a rare pancreatic neuroendocrine tumor. Overproduction of insulin and associated hypoglycemia are hallmark features of this disease. Diagnosis can be made through demonstration of hypoglycemia and elevated plasma levels of insulin or C-Peptide. Metastatic disease can be detected through computerized tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT. Somatostatin receptor scintigraphy can be used not only to document metastatic disease but also as a predictive marker of the benefit from therapy with radiolabeled somatostatin analog. Unresectable metastatic insulinomas may present as a major therapeutic challenge for the treating physician. When feasible, resection is the mainstay of treatment. Prevention of hypoglycemia is a crucial goal of therapy for unresectable/metastatic tumors. Diazoxide, hydrochlorothiazide, glucagon, and intravenous glucose infusions have been used for glycemic control yielding temporary and inconsistent results. Sandostatin and its long-acting depot forms have occasionally been used in the treatment of Octreoscan-positive insulinomas. Herein, we report a case of metastatic insulinoma with very difficult glycemic control successfully treated with the radiolabeled somatostatin analog lutetium ((177)LU). PMID:24455330

Costa, Ricardo; Costa, Rubens; Bacchi, Carlos E; Almeida Filho, Paulo

2013-01-01

337

A Glucose Sensor Protein for Continuous Glucose Monitoring  

OpenAIRE

In vivo continuous glucose monitoring has posed a significant challenge to glucose sensor development due to the lack of reliable techniques that are non-or at least minimally-invasive. In this proof-of-concept study, we demonstrated the development of a new glucose sensor protein, AcGFP1-GBPcys-mCherry, and an optical sensor assembly, capable of generating quantifiable FRET (fluorescence resonance energy transfer) signals for glucose monitoring. Our experimental data showed that the engineer...

Veetil, Jithesh V.; Jin, Sha; Ye, Kaiming

2010-01-01

338

Characterization of 6-deoxy-6-iodo-D-glucose: A potential new tool to assess glucose transport  

International Nuclear Information System (INIS)

6-deoxy-6-iodo-D-glucose (6-DIG) was rapidly taken up by adipocytes. Insulin increased 6-DIG transport in adipocytes isolated from both rats and mice. This stimulation was more important in rat than in mouse adipocytes, in agreement with their respective amount of Glut 4 transporters. In two insulin-resistant states, the biological behavior of 6-DIG and 3-O-methyl-D-glucose was similar. These results indicated that 6-DIG, which was transported into the cells via the glucose transporters, could be potentially useful to measure modifications of glucose transport

339

Portal venous 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside infusion overcomes hyperinsulinemic suppression of endogenous glucose output.  

Science.gov (United States)

AMP-activated protein kinase (AMPK) plays a key role in regulating metabolism, serving as a metabolic master switch. The aim of this study was to assess whether increased concentrations of the AMP analog, 5-aminoimidazole-4-carboxamide-1-beta-D-ribosyl-5-monophosphate, in the liver would create a metabolic response consistent with an increase in whole-body metabolic need. Dogs had sampling (artery, portal vein, hepatic vein) and infusion (vena cava, portal vein) catheters and flow probes (hepatic artery, portal vein) implanted >16 days before a study. Protocols consisted of equilibration (-130 to -30 min), basal (-30 to 0 min), and hyperinsulinemic-euglycemic or -hypoglycemic clamp periods (0-150 min). At t = 0 min, somatostatin was infused and glucagon was replaced in the portal vein at basal rates. An intraportal hyperinsulinemic (2 mU . kg(-1) . min(-1)) infusion was also initiated at this time. Glucose was clamped at hypoglycemic or euglycemic levels in the presence (H-AIC, n = 6; E-AIC, n = 6) or absence (H-SAL, n = 6; E-SAL, n = 6) of a portal venous 5-aminoimidazole-4-carboxamide-ribofuranoside (AICAR) infusion (1 mg . kg(-1) . min(-1)) initiated at t = 60 min. In the presence of intraportal saline, glucose was infused into the vena cava to match glucose levels seen with intraportal AICAR. Glucagon remained fixed at basal levels, whereas insulin rose similarly in all groups. Glucose fell to 50 +/- 2 mg/dl by t = 60 min in hypoglycemic groups and remained at 105 +/- 3 mg/dl in euglycemic groups. Endogenous glucose production (R(a)) was similarly suppressed among groups in the presence of euglycemia or hypoglycemia before t = 60 min and remained suppressed in the H-SAL and E-SAL groups. However, intraportal AICAR infusion stimulated R(a) to increase by 2.5 +/- 1.0 and 3.4 +/- 0.4 mg . kg(-1) . min(-1) in the E-AIC and H-AIC groups, respectively. Arteriovenous measurement of net hepatic glucose output showed similar results. AICAR stimulated hepatic glycogen to decrease by 5 +/- 3 and 19 +/- 5 mg/g tissue (P < 0.05) in the presence of euglycemia and hypoglycemia, respectively. AICAR significantly increased net hepatic lactate output in the presence of hypoglycemia. Thus, intraportal AICAR infusion caused marked stimulation of both hepatic glucose output and net hepatic glycogenolysis, even in the presence of high levels of physiological insulin. This stimulation of glucose output by AICAR was equally marked in the presence of both euglycemia and hypoglycemia. However, hypoglycemia amplified the net hepatic glycogenolytic response to AICAR by approximately fourfold. PMID:15677495

Camacho, Raul C; Pencek, R Richard; Lacy, D Brooks; James, Freyja D; Donahue, E Patrick; Wasserman, David H

2005-02-01

340

Continuous Glucose Monitoring  

Science.gov (United States)

... first pairing of a CGM system with an insulin pump—the MiniMed Paradigm REAL-Time System—is not an artificial pancreas, but it does represent the first step in joining glucose monitoring and insulin delivery systems using the most advanced ...

341

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... 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 Home Symptoms Diagnosis Type 1 Type 2 Facts About Type 2 Enroll in the Living ...

342

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Health Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy ... June 7, 2013 Last Edited: September 16, 2014 Articles from Diabetes Forecast® magazine: bg-and-a1c-hyperglycemia, ...

343

Conditions With High Intracellular Glucose Inhibit Sensing Through Glucose Sensor Snf3 in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

Gene expression in micro-organisms is regulated according to extracellular conditions and nutrient concentrations. In Saccharomyces cerevisiae, non-transporting sensors with high sequence similarity to transporters, that is, transporter-like sensors, have been identified for sugars as well as for amino acids. An alternating-access model of the function of transporter-like sensors has been previously suggested based on amino acid sensing, where intracellular ligand inhibits binding of extracellular ligand. Here we studied the effect of intracellular glucose on sensing of extracellular glucose through the transporter-like sensor Snf3 in yeast. Sensing through Snf3 was determined by measuring degradation of Mth1 protein. High intracellular glucose concentrations were achieved by using yeast strains lacking monohexose transporters which were grown on maltose. The apparent affinity of extracellular glucose to Snf3 was measured for cells grown in non-fermentative medium or on maltose. The apparent affinity for glucose was lowest when the intracellular glucose concentration was high. The results conform to an alternating-access model for transporter-like sensors. J. Cell. Biochem. 110: 920-925, 2010.

Karhumaa, Kaisa; Wu, B.Q.

2010-01-01

344

Functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose.  

Science.gov (United States)

In this article, we report a functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose. To adjust the sensor for intracellular glucose measurements, we grew hexagonal ZnO nanorods on the tip of a silver-covered borosilicate glass capillary (0.7 microm diameter) and coated them with the enzyme glucose oxidase. The enzyme-coated ZnO nanorods exhibited a glucose-dependent electrochemical potential difference versus an Ag/AgCl reference microelectrode. The potential difference was linear over the concentration range of interest (0.5-1000 microM). The measured glucose concentration in human adipocytes or frog oocytes using our ZnO-nanorod sensor was consistent with values of glucose concentration reported in the literature; furthermore, the sensor was able to show that insulin increased the intracellular glucose concentration. This nanoelectrode device demonstrates a simple technique to measure intracellular glucose concentration. PMID:20303253

Asif, Muhammad H; Ali, Syed M Usman; Nur, Omer; Willander, Magnus; Brännmark, Cecilia; Strålfors, Peter; Englund, Ulrika H; Elinder, Fredrik; Danielsson, Bengt

2010-06-15

345

Structure-function relationships affecting the sensing mechanism of monolayer-protected cluster doped xerogel amperometric glucose biosensors.  

Science.gov (United States)

A systematic study of the structure-function relationships critical to understanding the sensing mechanism of 1st generation amperometric glucose biosensors with an embedded nanoparticle (NP) network is presented. Xerogel-based films featuring embedded glucose oxidase enzyme and doped with alkanethiolate-protected gold NPs, known as monolayer protected clusters (MPCs), exhibit significantly enhanced performance compared to analogous systems without NPs including higher sensitivity, faster response time, and extended linear/dynamic ranges. The proposed mechanism involves diffusion of the glucose to glucose oxidase within the xerogel, enzymatic reaction production of H2O2 with subsequent diffusion to the embedded network of MPCs where it is oxidized, an event immediately reported via fast electron transfer (ET) through the MPC system to the working electrode. Various aspects of the film construct and strategy are systematically probed using amperometry, voltammetry, and solid-state electronic conductivity measurements, including the effects of MPC peripheral chain length, MPC functionalization via place-exchange reaction, MPC core size, and the MPC density or concentration within the xerogel composite films. The collective results of these experiments support the proposed mechanism and identify interparticle spacing and the electronic communication through the MPC network is the most significant factor in the sensing scheme with the diffusional aspects of the mechanism that may be affected by film/MPC hydrophobicity and functionality (i.e., glucose and H2O2 diffusion) shown to be less substantial contributors to the overall enhanced performance. Understanding the structure-function relationships of effective sensing schemes allows for the employment of the strategy for future biosensor design toward clinically relevant targets. PMID:25819004

DiPasquale, Luke T; Poulos, Nicholas G; Hall, Jackson R; Minocha, Aastha; Bui, Tram Anh; Leopold, Michael C

2015-07-15

346

Identification and quantification of sophorolipid analogs using ultra-fast liquid chromatography-mass spectrometry.  

Science.gov (United States)

An ultra-fast liquid chromatographic method combined with atmospheric pressure chemical ionization mass detection (UHPLC/APCI-MS) has been developed for the separation and quantification of sophorolipid analogs produced by the yeast Candida bombicola. The sophorolipid mixture was produced by growing the yeast in the presence of glucose and oleic acid under higher aeration. It was found that more than 95% of the analogs are lactonic sophorolipids and all the produced sophorolipids produced were either mono- or di-acetylated. Also observed was a sophorolipid analog with a tri-unsaturated fatty acid, which has not been reported previously. PMID:19559734

Ratsep, Peter; Shah, Vishal

2009-09-01

347

Effect of erythropoietin on the glucose transport of rat erythrocytes and bone marrow cells  

International Nuclear Information System (INIS)

The effect of Ep on radioactive glucose and methyl-alpha-D-glucoside transport by rat erythrocytes and bone marrow cells were studied. There is initial linearity followed by saturation kinetics of [14C]glucose transport by the erythrocytes of starved and starved plus Ep-treated rats at different concentrations of glucose. Starvation caused slight inhibition of glucose transport which increased markedly on Ep administration to starved rats. Normal animals failed to show any significant change in glucose transport after Ep treatment. Methyl-alpha-D-glucoside inhibited the Ep-stimulated glucose transport significantly. Ep also stimulated the transport of radioactive methyl-alpha-D-glucoside which was competitively inhibited in presence of D-glucose. Glucose transport in erythrocytes was found to be sensitive to metabolic inhibitors like azide and DNP. A sulfhydryl reagent and ouabain also inhibited the transport process. Ep stimulated glucose and methyl-alpha-D-glucoside transport in the bone marrow cells of starved rats. The sugar analog competitively inhibited the glucose transport in bone marrow cells and vice versa

348

Predictive models of glucose control: roles for glucose-sensing neurones.  

Science.gov (United States)

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 (from liver, into muscle) are balanced. Estimating nutrient challenges from indirect sensory cues may become more difficult when the cues become complex and variable (e.g. like human foods today). Consequent errors of predictive glucose control may contribute to obesity and diabetes. PMID:25131833

Kosse, C; Gonzalez, A; Burdakov, D

2015-01-01

349

Analog cavity simulator  

Energy Technology Data Exchange (ETDEWEB)

Most of the low-level radio frequency (LLRF) systems are being developed well before the machines are being set up and ready to be commissioned. Therefore it is imperative to be able to test and evaluate their functionality and performance in the laboratory, before the instrument is installed in the final configuration. Real accelerator cavities are very expensive and frequency-dependent, hence impractical for mass factory testing of instrumentation. As an alternative, we developed an analog cavity simulator. The article gives an explanation of the main design concept, some key considerations of its implementation in order to reach the required specifications, and presents the test results, showing the simulator performance. -- Highlights: •Presentation of a novel approach for the design principle. •Extensive description of key technical features of the design implementation. •Presentation of a cheap and easily manufacturable prototype. •Proof of concept and proof of performance results. •Discussion for further improvement of the design implementation.

Orel, Peter, E-mail: peter.orel@i-tech.si; Mavri?, Uroš

2013-11-21

350

Digital-Analog Conversion  

Science.gov (United States)

All About Circuits is a website that â??provides a series of online textbooks covering electricity and electronics.â? Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Digital-Analog Conversion, is the thirteenth chapter in Volume IV â??Digital. A few of the topics covered in this chapter include: The R/2nR DAC, Digital ramp ADC, and Slope (integrating) ADC. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

351

Practical Analog Semiconductor Circuits  

Science.gov (United States)

All About Circuits is a website that â??provides a series of online textbooks covering electricity and electronics.â? Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Practical Analog Semiconductor Circuits, is the ninth chapter in Volume III â??Semiconductors. A few of the topics covered in this chapter include: ElectroStatic Discharge; Computational circuits; and Oscillator circuits. As of June 2009, a few of the subjects in this chapter were still incomplete, but the site is updated regularly and this chapter should soon be complete. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

352

Glucose metabolism in mice during and after whole-body hyperthermia  

International Nuclear Information System (INIS)

Researchers studied glucose turnover in male inbred mice during and after whole-body hyperthermia for 1 hour at 40 degrees or 41 degrees C by giving them injections of [14C]glucose with and without a glucose load and measuring the expired 14Co2. Expiration of 14CO2 was increased during hyperthermia but decreased considerably afterward. The latter effect was enhanced by a glucose load. This inhibition depended on the glucose concentration. Metabolic studies showed a depletion of several glycolytic metabolites, especially glycogen and lactate, after whole-body hyperthermia. Combined treatment of hyperthermia and a glucose injection 1 hour later led to an increased level of glucose 6-phosphate, which indicated a block in glycolysis between glucose 6-phosphate and fructose 1,6-diphosphate. This inhibition did not occur when glucose was given before the hyperthermia treatment. Lactate accumulation was not observed under any conditions

353

D-Lactate production as a function of glucose metabolism in Saccharomyces cerevisiae.  

Science.gov (United States)

Methylglyoxal, a reactive, toxic dicarbonyl, is generated by the spontaneous degradation of glycolytic intermediates. Methylglyoxal can form covalent adducts with cellular macromolecules, potentially disrupting cellular function. We performed experiments using the model organism Saccharomyces cerevisiae, grown in media containing low, moderate and high glucose concentrations, to determine the relationship between glucose consumption and methylglyoxal metabolism. Normal growth experiments and glutathione depletion experiments showed that metabolism of methylglyoxal by log-phase yeast cultured aerobically occurred primarily through the glyoxalase pathway. Growth in high-glucose media resulted in increased generation of the methylglyoxal metabolite D-lactate and overall lower efficiency of glucose utilization as measured by growth rates. Cells grown in high-glucose media maintained higher glucose uptake flux than cells grown in moderate-glucose or low-glucose media. Computational modelling showed that increased glucose consumption may impair catabolism of triose phosphates as a result of an altered NAD?:NADH ratio. PMID:23361949

Stewart, Benjamin J; Navid, Ali; Kulp, Kristen S; Knaack, Jennifer L S; Bench, Graham

2013-02-01

354

Impact of incretin on early-phase insulin secretion and glucose excursion.  

Science.gov (United States)

This study investigated the impact of incretin on early-phase insulin secretion and glucose excursion. The normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM) groups included 16, 8, and 19 subjects, respectively. Subjects underwent continuous glucose monitoring for 3 days, followed by an oral glucose tolerance test. Plasma glucose, insulin, glucagon, total glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-l (GLP-1) levels were measured at 30-min increments for 2 h after glucose intake. Differences with P 0.464), but uncorrelated with ?I30/?G30. The 120-min GLP-1-AUC was positively correlated with ?I30/?G30 (r = 0.580), but negatively correlated with MAGE (r = -0.606). Incretin may ameliorate glucose excursions, and GLP-1 may exert them by promoting early-phase insulin secretion. No correlation was observed between GIP secretion and early-phase insulin secretion. PMID:23283820

Shen, Jie; Chen, Zhi; Chen, Chaofeng; Zhu, Xiao; Han, Yajuan

2013-10-01

355

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)

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

356

¿Podemos confiar en una glicemia realizada en un glucómetro al lado de la cama del enfermo? / Are blood glucose measurements made with portable glucometers reliable?  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish los exámenes realizados al lado de la cama del enfermo f'Point of care testing, POCT") tienen como mayor ventaja la rapidez en la entrega de resultados y la simplicidad de uso, siendo su principal aplicación el autocontrol de la glicemia en pacientes diabéticos. El uso de estos equipos a nivel hospi [...] talario introduce exigencias a las instituciones de salud, las cuales deben monitorizar todos ¡os aspectos del proceso, incluyendo la capacitación de los usuarios, el adecuado control de calidad, el desarrollo de procedimientos escritos para su uso e inclusive la participación en encuestas de control de calidad externo, evitando la generación de errores y colaborando así con la seguridad del paciente. Abstract in english Examinations performed beside the bed of patients ('Point-ofcare testing, POCT") provide immediate results and are simple to perform. The most common of these tests is the self control of blood glucose levels in diabetic patients. The use of these devices at the hospital level, introduces a new set [...] of requirements to health institutions, which should monitor all aspects of the process, including training of final users, proper quality control, development of written procedures for use and even participation in surveys of external quality control, avoiding the generation of errors and guaranting patient safety (Rev Méd Chile 2009; 137:1261-4).

Ana María, Guzmán D; Teresa, Quiroga G.

1261-12-01

357

Beginning analog electronics through projects  

CERN Document Server

Analog electronics is the simplest way to start a fun, informative, learning program. Beginning Analog Electronics Through Projects, Second Edition was written with the needs of beginning hobbyists and students in mind. This revision of Andrew Singmin's popular Beginning Electronics Through Projects provides practical exercises, building techniques, and ideas for useful electronics projects. Additionally, it features new material on analog and digital electronics, and new projects for troubleshooting test equipment.Published in the tradition of Beginning Electronics Through Projects an

Singmin, Andrew

2001-01-01

358

Analogical Modeling and Quantum Computing  

OpenAIRE

This paper serves as a bridge between quantum computing and analogical modeling (a general theory for predicting categories of behavior in varying contexts). Since its formulation in the early 1980s, analogical modeling has been successfully applied to a variety of problems in language. Several striking similarities between quantum mechanics and analogical modeling have recently been noted: (1) traditional statistics can be derived from a non-statistical basis by assuming da...

Skousen, Royal

2000-01-01

359

ESD design for analog circuits  

CERN Document Server

This book is on high voltage and system level circuit design. It covers many challenging ESD topics related to analog circuit design for both ESD device and ESD circuits at the network level. Included is extensive discussion of analog design for DC-DC buck/boost converters, level shifters, digital-analog converters, high speed and precision power amplifiers, and system level cable specs for interface applications.

Vashchenko, Vladislav A

2010-01-01

360

FET comparator detects analog signal levels without loading analog device  

Science.gov (United States)

FET comparator circuit detects discrete analog computer output levels without excessively loading the output amplifier of the computer. An FET common source amplifier is coupled by a differential amplifier to a bistable transistor flip-flop. This circuit provides a digital output for analog voltages above or below a predetermined level.

Wallace, H. L.

1966-01-01

361

The interaction among glucose transport, hexokinase, and glucose-6-phosphatase with respect to 3H-2-deoxyglucose retention in murine tumor model  

International Nuclear Information System (INIS)

The development of new diagnostic/therapeutic modalities for cancer requires a specific understanding of how tumors differ from normal tissues. Though the key components involved in the selective accumulation of 2-deoxy-D-glucose (2-DG) analogs in tumors are known, the relative importance of each is controversial. For this reason glucose transport protein (GLUT) density, hexokinase/glucose-6-phosphatase (GP) activity, and 2-DG biodistribution were measured together in four tumor models and normal murine tissues. Direct binding studies with 3H-cytochalasin B showed that GLUT density was elevated 20-fold in LX-1 tumors. Immunohistochemically in all tumors, the expression of GLUT-1 was highest in the necrotic/perinecrotic foci and similar in cells not adjacent to necrotic foci. As the retention of 3H-2-DG was similar in all tumors, these data suggest that the GLUT-1 in perinecrotic tumor cells were not rate limiting for 3H-2-DG uptake. Kidney, liver, and lung had high GP activity and rapid clearance of 3H-2-DG. Sodium orthovanadate (5 ?mol), a GP inhibitor, increased the concentration of 3H-2-DG in these tissues, suggesting that GP is a rate-limiting enzyme for 3H-2-DG clearance. All tumor homogenates had low GP activity, and hexokinase activity was not elevated compared to normal tissues. Thus, in the tumors studied, the selective accumulation of 3H-2-DG consistently occurred in the absence ofG consistently occurred in the absence of significant GP activity without the marked overexpression of hexokinase or GLUT

362

The interaction among glucose transport, hexokinase, and glucose-6-phosphatase with respect to {sup 3}H-2-deoxyglucose retention in murine tumor model  

Energy Technology Data Exchange (ETDEWEB)

The development of new diagnostic/therapeutic modalities for cancer requires a specific understanding of how tumors differ from normal tissues. Though the key components involved in the selective accumulation of 2-deoxy-D-glucose (2-DG) analogs in tumors are known, the relative importance of each is controversial. For this reason glucose transport protein (GLUT) density, hexokinase/glucose-6-phosphatase (GP) activity, and 2-DG biodistribution were measured together in four tumor models and normal murine tissues. Direct binding studies with {sup 3}H-cytochalasin B showed that GLUT density was elevated 20-fold in LX-1 tumors. Immunohistochemically in all tumors, the expression of GLUT-1 was highest in the necrotic/perinecrotic foci and similar in cells not adjacent to necrotic foci. As the retention of {sup 3}H-2-DG was similar in all tumors, these data suggest that the GLUT-1 in perinecrotic tumor cells were not rate limiting for {sup 3}H-2-DG uptake. Kidney, liver, and lung had high GP activity and rapid clearance of {sup 3}H-2-DG. Sodium orthovanadate (5 {mu}mol), a GP inhibitor, increased the concentration of {sup 3}H-2-DG in these tissues, suggesting that GP is a rate-limiting enzyme for {sup 3}H-2-DG clearance. All tumor homogenates had low GP activity, and hexokinase activity was not elevated compared to normal tissues. Thus, in the tumors studied, the selective accumulation of {sup 3}H-2-DG consistently occurred in the absence of significant GP activity without the marked overexpression of hexokinase or GLUT.

Nelson, Carol A.; Wang, Jennifer Q.; Leav, Irwin; Crane, Paul D

1996-05-01

363

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

International Nuclear Information System (INIS)

Entry rates of glucose have been measured in buffalo calves by using a dual-isotope dilution method based on continuous infusion of (U-14C)D-glucose and (6-3H)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 14C and 3H labelled glucose respectively. About 23 percent of the glucose carbon was recycled in the pool. The average recycling rate was 33 mg/min. (author)

364

Novel phosphoenolpyruvate-dependent futile cycle in Streptococcus lactis: 2-deoxy-D-glucose uncouples energy production from growth.  

OpenAIRE

The addition of 2-deoxy-D-glucose to cultures of Streptococcus lactis 133 that were growing exponentially on sucrose or lactose reduced the growth rate by ca. 95%. Inhibition did not occur with glucose or mannose as the growth sugar. The reduction in growth rate was concomitant with rapid accumulation of the analog in phosphorylated form (2-deoxy-D-glucose 6-phosphate) via the phosphoenolpyruvate-dependent mannose:phosphotransferase system. Within 5 min the intracellular 2-deoxy-D-glucose 6-p...

Thompson, J.; Chassy, B. M.

1982-01-01

365

Analogic fiber optic position sensor with nanometric resolution  

OpenAIRE

This paper describes a miniature analogic position sensor. This sensor is dedicated to high resolution displacement measurement (10 nm) between two positions on long range (few millimeters). The working principle of the sensor is presented as well as experimentation results.

Lamarque, Fre?de?ric; Prelle, Christine

2002-01-01

366

Natural analog studies: Licensing perspective  

Energy Technology Data Exchange (ETDEWEB)

This report describes the licensing perspective of the term {open_quotes}natural analog studies{close_quotes} as used in CFR Part 60. It describes the misunderstandings related to its definition which has become evident during discussions at the U.S Nuclear Regulatory Commission meetings and tries to clarify the appropriate applications of natural analog studies to aspects of repository site characterization.

Bradbury, J.W. [Nuclear Regulatory Commission, Washington, DC (United States)

1995-09-01

367

Analog pixel array detectors.  

Science.gov (United States)

X-ray pixel array detectors (PADs) are generally thought of as either digital photon counters (DPADs) or X-ray analog-integrating pixel array detectors (APADs). Experiences with APADs, which are especially well suited for X-ray imaging experiments where transient or high instantaneous flux events must be recorded, are reported. The design, characterization and experimental applications of several APAD designs developed at Cornell University are discussed. The simplest design is a ;flash' architecture, wherein successive integrated X-ray images, as short as several hundred nanoseconds in duration, are stored in the detector chips for later off-chip digitization. Radiography experiments using a prototype flash APAD are summarized. Another design has been implemented that combines flash capability with the ability to continuously stream X-ray images at slower (e.g. milliseconds) rates. Progress is described towards radiation-hardened APADs that can be tiled to cover a large area. A mixed-mode PAD, design by combining many of the attractive features of both APADs and DPADs, is also described. PMID:16495611

Ercan, A; Tate, M W; Gruner, S M

2006-03-01

368

Mitsubishi analog controller MELNAC  

International Nuclear Information System (INIS)

For recent power generating plants, high reliability is more and more required, while their capacity is increasing and they are becoming more complicated and sophisticated. Especially in nuclear power plants, in addition to the keen requirement for high reliability, high aseismatic property and signal selectivity are the specific requirements. MELNAC, an analog controller, has been developed as the process control system used for nuclear power plants. The main features are high reliability, high aseismatic property, reduction of required floor space, and shortening of the periods for wiring, field adjustment and testing. Next, the outline of the system is described, such as signal and power supply systems and the specifications of each card, which are listed in a table. The performance was confirmed by the two-stage test of card and system levels, respectively. For the card level, accuracy, frequency characteristics, drift, supply voltage variation, temperature characteristics, humidity endurance, aseismatic property, isolation and others were tested, and the excellent performance was confirmed. For the system level, the primary coolant temperature difference/mean temperature protection system was selected as a typical system, and the type test was carried out. As described above, various performance checking tests were now completed, and the systems have been delivered to many loops in nuclear power plants. (Wakatsuki, Y.)

369

Optical analog transmission device  

International Nuclear Information System (INIS)

The present invention concerns a device such as electro-optical conversion elements, optoelectric-electric elements and optical transmission channel, not undergoing deleterious effects on the efficiency of conversion and transmission due to temperature, and aging change. That is, a sine wave superposing means superposes, on a detector signal to be transmitted, a sine-wave signal having a predetermined amplitude and at a frequency lower than that of the detector signal. An optoelectric conversion means converts the electric signal as the signal of the sine-wave signal superposing means into an optical signal and outputs the same to an optical transmitting channel. The optoelectric conversion means converts the transmitted signal to an electric signal. A discriminating means discriminates the electric signal into a detector signal and a sine-wave signal. A calculating means calculates an optical transmitting efficiency of the transmitting channel based on the amplitude of the discriminated sine-wave signal. A processing means compensates an amplitude value of the detector signals discriminated by the discriminating means based on the optical transmission efficiency. As a result, an optical analog transmission device can be attained, which conducts optical transmission at a high accuracy without undergoing the defective effects of the optical transmission efficiency. (I.S.)

370

Influence of glucose and urea on 125I transport across an anion exchange paper membrane  

International Nuclear Information System (INIS)

In order to study the influence of glucose and urea on the 125I transport across an anion exchange paper membrane, the transmembrane potential, the fluxes, and the concentrations of 125I, glucose and urea within the membrane were measured in the Na125I concentration-cell system containing glucose or urea. Glucose and urea increased the membrane/solution distribution of the iodide ion, but scarcely affected the diffusion process of iodide ion within the membrane

371

Growth Landscape Formed by Perception and Import of Glucose in Yeast  

OpenAIRE

An important challenge in systems biology is to quantitatively describe microbial growth using a few measurable parameters that capture the essence of this complex phenomenon. Two key events at the cell membrane—extracellular glucose sensing and uptake—initiate the budding yeast’s growth on glucose. However, conventional growth models focus almost exclusively on glucose uptake. Here we present results from growth-rate experiments that cannot be explained by focusing on glucose uptake al...

Youk, Hyun; Oudenaarden, Alexander

2009-01-01

372

Continuous glucose monitoring system and new era of early diagnosis of diabetes in high risk groups  

OpenAIRE

Continuous glucose monitoring (CGM) systems are an emerging technology that allows frequent glucose measurements to monitor glucose trends in real time. Their use as a diagnostic tool is still developing and appears to be promising. Combining intermittent glucose self-monitoring (SGM) and CGM combines the benefits of both. Significant improvement in the treatment modalities that may prevent the progress of prediabetes to diabetes have been achieved recently and dictates screening of high risk...

Soliman, Ashraf; Desanctis, Vincenzo; Yassin, Mohamed; Elalaily, Rania; Eldarsy, Nagwa E.

2014-01-01

373

IDegAsp : a novel soluble insulin analogs combination  

DEFF Research Database (Denmark)

INTRODUCTION: Current rapid- and long-acting insulin analogs cannot maintain their individual pharmacokinetic profile when they are co-formulated. IDegAsp , a novel soluble combination was developed with rapid-acting insulin aspart and a new-generation ultra-long-acting insulin, insulin degludec and was anticipated to offer clinical advantage over available premixed insulin suspensions. AREAS COVERED: We reviewed published data regarding pharmacological characters, clinical efficacy, safety, and tolerability of IDegAsp. Literature was searched through the electronic medical databases (PubMed, EMBASE, and Web of Knowledge) up to June 2012. EXPERT OPINION: Preliminary clinical data indicate that IDegAsp is a safe, well-tolerated insulin combination and provides a similar overall glycemic control to current insulin preparations with a reduced risk of hypoglycemia. IDegAsp might be a promising treatment option for patients with type 2 diabetes who need to improve control of postprandial glucose excursions and fasting glucose levels.

Ma, Zhulin; Parkner, Tina

2012-01-01

374

Statins Impair Glucose Uptake in Tumor Cells1  

Science.gov (United States)

Statins, HMG-CoA reductase inhibitors, are used in the prevention and treatment of cardiovascular diseases owing to their lipid-lowering effects. Previous studies revealed that, by modulating membrane cholesterol content, statins could induce conformational changes in cluster of differentiation 20 (CD20) tetraspanin. The aim of the presented study was to investigate the influence of statins on glucose transporter 1 (GLUT1)-mediated glucose uptake in tumor cells. We observed a significant concentration- and time-dependent decrease in glucose analogs' uptake in several tumor cell lines incubated with statins. This effect was reversible with restitution of cholesterol synthesis pathway with mevalonic acid as well as with supplementation of plasma membrane with exogenous cholesterol. Statins did not change overall GLUT1 expression at either transcriptional or protein levels. An exploratory clinical trial revealed that statin treatment decreased glucose uptake in peripheral blood leukocytes and lowered 18F-fluorodeoxyglucose (18F-FDG) uptake by tumor masses in a mantle cell lymphoma patient. A bioinformatics analysis was used to predict the structure of human GLUT1 and to identify putative cholesterol-binding motifs in its juxtamembrane fragment. Altogether, the influence of statins on glucose uptake seems to be of clinical significance. By inhibiting 18F-FDG uptake, statins can negatively affect the sensitivity of positron emission tomography, a diagnostic procedure frequently used in oncology. PMID:22577346

Malenda, Agata; Skrobanska, Anna; Issat, Tadeusz; Winiarska, Magdalena; Bil, Jacek; Oleszczak, Bozenna; Sinski, Maciej; Firczuk, Ma?gorzata; Bujnicki, Janusz M; Chlebowska, Justyna; Staruch, Adam D; Glodkowska-Mrowka, Eliza; Kunikowska, Jolanta; Krolicki, Leszek; Szablewski, Leszek; Gaciong, Zbigniew; Koziak, Katarzyna; Jakobisiak, Marek; Golab, Jakub; Nowis, Dominika A

2012-01-01

375

Evaluation of a novel supplement to reduce blood glucose through the use of a modified oral glucose tolerance test  

Science.gov (United States)

Elevated blood glucose is a major component in metabolic syndrome and pre-diabetes, sometimes leading to type 2 diabetes mellitus (DM II). Additionally, it may lead to adipose deposits when left elevated for long periods. The epidemiology of DM II clearly shows that uncontrolled blood glucose levels leads to many adverse conditions including heart disease, retinal damage, renal failure, erectile dysfunction, and other significant medical conditions. Here we conducted a single-center, prospective, randomized, double-blinded, placebo-controlled, parallel-group- clinical trial of a nutraceutical supplement vs. placebo to measure its glucose lowering effect in generally healthy adults before and after a simple sugars meal. Subjects reported to the test clinic on multiple days to receive placebo or treatment, a simple sugars meal, as well as pre-and postprandial blood glucose measurement (modified oral glucose tolerance test). Each subject served as his or her own control and thirty-one subjects completed the trial with at least one oral glucose tolerance test (OGTT) with the nutraceutical supplement and placebo. Statistical analysis revealed the nutraceutical supplement significantly lowered postprandial glucose levels by 36% and 59% at 45 and 60 minutes, respectively (***P<.001). The study was limited by its composition of primarily overweight females. Future studies will be required over longer periods in more heterogeneous and larger groups to determine the long-term effect of this supplement on blood glucose levels in terms of prophylaxis or treatment for DM II. PMID:21416063

Smith, Adam J; Giunta, Brian; Shytle, R Douglas; Blum, James M

2011-01-01

376

Insulin-like growth factor-I correlates more closely than growth hormone with insulin resistance and glucose intolerance in patients with acromegaly.  

Science.gov (United States)

In normal subjects growth hormone (GH) and insulin-like growth factor-I (IGF-I) have opposing effects on glucose metabolism. Active acromegaly is associated with insulin resistance (IR) and glucose intolerance although both GH and IGF-I are elevated. Our objective was to compare whether GH or IGF-I correlates more closely with IR and glucose intolerance in acromegaly. Basal serum IGF-I and GH, glucose and insulin during an oral glucose tolerance test were measured in 70 normoglycemic and 44 hyperglycemic acromegalic patients (21 impaired fasting glucose, 11 impaired glucose tolerance and 12 diabetes mellitus) according to American Diabetes Association criteria. 55 patients were assessed before any treatment for acromegaly and 59 after surgery and/or radiotherapy (15 patients had normal IGF-I after treatment). Patients treated with somatostatin analogs, GH-receptor antagonists or antidiabetic drugs were excluded. IR was assessed by various basal and stimulated indices. Homeostatic Model Assessment 2-Insulin Resistance (HOMA2-IR) index correlated more closely with IGF-I (r = 0.65, p < 0.0001) than nadir (r = 0.23, p = 0.008) or random GH (r = 0.26, p = 0.002). HOMA2-IR correlated better with IGF-I than nadir or random GH also in normoglycemic (n = 70; r = 0.74, p < 0.0001 vs. r = 0.36, p = 0.001 vs. r = 0.39, p < 0.001) and hyperglycemic patients (n = 44; r = 0.54, p = 0.0002 vs. r = 0.09, p = 0.4 vs. r = 0.14, p = 0.26). In multivariate logistic regression analysis IGF-I but not GH was a significant risk factor for glucose intolerance after adjusting for age, sex, weight and acromegaly duration (OR = 1.56, p = 0.01). In acromegaly IGF-I correlates more closely than GH with IR. IGF-I levels but not GH are associated with glucose intolerance. PMID:22562529

Niculescu, Dan; Purice, Mariana; Coculescu, Mihail

2013-06-01

377

Análise de diferentes medidas antropométricas na identificação de síndrome metabólica, com ou sem alteração do metabolismo glicídico Analysis of several anthropometric measurements for the identification of metabolic syndrome, with or without disturbance of glucose metabolism  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Este estudo comparou parâmetros antropométricos e de resistência à insulina de indivíduos sem e com síndrome metabólica (SM, subestratificados pela presença de anormalidades glicêmicas. SUJEITOS E MÉTODOS: Foram incluídos 454 indivíduos (66% mulheres, 54% brancos, sendo 155 alocados para o grupo 1 (sem SM, sem anormalidade glicêmica, 32 para o grupo 2 (sem SM, com anormalidade glicêmica, 104 no grupo 3 (com SM, sem anormalidade glicêmica e 163 no grupo 4 (com SM e anormalidade glicêmica. Os grupos foram comparados por ANOVA. RESULTADOS: Os grupos com SM (3 e 4 apresentaram os piores perfis antropométrico e lipídico; no grupo 2, apesar de glicemias significantemente mais elevadas, as médias das variáveis antropométricas e lipídicas não diferiram do grupo 1. Os maiores valores médios de HOMA-IR foram encontrados nos grupos com SM, enquanto o grupo 2 apresentou o menor HOMA-?. A trigliceridemia foi a variável metabólica com coeficientes de correlação mais elevados com a antropometria. Porém, as correlações mais fortes foram da circunferência da cintura (r = 0,503 e da razão cintura-altura (r = 0,513 com o HOMA-IR (p OBJECTIVE: This study compared anthropometric measurements and insulin resistance indexes of individuals with or without metabolic syndrome (MS, stratified by the presence of glycemic abnormalities. SUBJECTS AND METHODS: 454 individuals (66% women, 54% Caucasians were included, being 155 allocated to group 1 (without MS, without glycemic abnormality, 32 to group 2 (without MS, with glycemic abnormality, 104 to group 3 (with MS, without glycemic abnormality, and 163 to group 4 (with MS, with glycemic abnormality. Groups were compared by ANOVA. RESULTS: Those with MS (3 e 4 showed the worst anthropometric and lipid profiles; in group 2, despite higher plasma glucose levels, the mean values of anthropometric variables and lipids did not differ from group 1. The highest mean values of HOMA-IR were found in the groups with MS, while group 2 showed the lowest HOMA-?. Triglyceride was the metabolic variable with the highest correlation coefficients with anthropometry. However, the strongest correlations were those of waist circumference (r = 0.503 and waist-to-height ratio (r = 0.513 with HOMA-IR (p < 0.01. CONCLUSION: Our findings indicate that, in a sample of the Brazilian population, any anthropometric measure identifies individuals with MS, but such measurements seem to be unable to differentiate those with glycemic disturbance. We reinforce the strongest relationship of measures of central adiposity with insulin resistance, suggesting utility for the waist-to-height. An autoimmune component may be contributing to the deterioration of glucose metabolism of individuals from group 2.

Natália Pereira da Rocha

2010-10-01

378

Placental-Fetal Glucose Exchange and Fetal Glucose Metabolism  

OpenAIRE

Fetal glucose metabolism depends on additive effects of fetal plasma glucose and insulin. Glucose-stimulated insulin secretion increases over gestation, is down-regulated by constant hyperglycemia, but enhanced by pulsatile hyperglycemia. Insulin production is diminished in fetuses with intrauterine growth restriction (IUGR) by inhibition of pancreatic ?-cell replication, but not by mechanisms that regulate insulin production or secretion, while the opposite occurs with hypoglycemia alone, d...

Hay, William W.

2006-01-01

379

Quantitative kinetics of renal glucose metabolism by the isotope dilution method in the unanesthetized sheep  

International Nuclear Information System (INIS)

Renal glucose production and utilization rates in normal fed and fasted sheep were determined by the measurements of renal blood flow and arteriovenous 14C-glucose and glucose concentration differences using the method of primed continuous infusion of u-14C-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 anproduce a significant amount of glucose and to utilize it simultaneously with production. (author)

380

Impaired fasting glucose individuals: their response to oral glucose challenge  

International Nuclear Information System (INIS)

To determine the frequency of Impaired Fasting Glucose (IFG) individuals in symptom free adults and their 2-h PG (two-hour plasma glucose) concentrations in standard Oral Glucose Tolerance Test (OGTT) with 75-g glucose. Fasting plasma glucose (FPG) of 859 symptom free adults was checked. Of them, 344(40%) were found to have IFG, who were subjected to standard OGTT with 75-g glucose and their 2-h PG results were recorded. Frequency distribution of FPG of 859 symptom free adults showed, 455(53%) were Normal Fasting Glucose (NFG 7.0 mmol/l). The difference in frequency of three groups of FPG was statistically significant (p<0.0001). Of 344 IFG individuals, who were subjected to standard OGTT, 182(53%) had Normal Glucose Tolerance (NGT), 127(37%) were Impaired Glucose Tolerance (IGT) and 35(10%) were diabetics. The difference in frequency of the three groups was statistically significant (p<0.0001). A significantly large number of asymptomatic adults are suffering from IFG in our set up. When IFG individuals are subjected to 75-g OGTT, their 2-h PG results showed about one third have IGT and also a significant number of IFG individuals are found to be patients of diabetes. (author)

381

Analog filters in nanometer CMOS  

CERN Document Server

Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehen

Uhrmann, Heimo; Zimmermann, Horst

2013-01-01

382

Molecular modeling of fentanyl analogs  

Directory of Open Access Journals (Sweden)

Full Text Available Fentanyl is a highly potent and clinically widely used narcotic analgesic. A large number of its analogs have been synthesized, some of which (sufentanil and alfentanyl are also in clinical use. Theoretical studies, in recent years, afforded a better understanding of the structure-activity relationships of this class of opiates and allowed insight into the molecular mechanism of the interactions of fentanyl analogs with their receptors. An overview of the current computational techniques for modeling fentanyl analogs, their receptors and ligand-receptor interactions is presented in this paper.

LJILJANA DOSEN-MICOVIC

2004-11-01

383

The association between estimated average glucose levels and fasting plasma glucose levels in a rural tertiary care centre  

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Full Text Available The level of hemoglobin A1c (HbA1c, also known as glycated hemoglobin, determines how well a patient’s blood glucose level has been controlled over the previous 8-12 weeks. HbA1c levels help patients and doctors understand whether a particular diabetes treatment is working and whether adjustments need to be made to the treatment. Because the HbA1c level is a marker of blood glucose for the previous 60- 90 days, average blood glucose levels can be estimated using HbA1c levels. Aim in the present study was to investigate the relationship between estimated average glucose levels, as calculated by HbA1c levels, and fasting plasma glucose levels. Methods: Type 2 diabetes patients attending medicine outpatient department of RL Jalappa hospital, Kolar between March 2010 and July 2012 were taken. The estimated glucose levels (mg/dl were calculated using the following formula: 28.7 x HbA1c-46.7. Glucose levels were determined using the hexokinase method. HbA1c levels were determined using an HPLC method. Correlation and independent t- test was the test of significance for quantitative data. Results: A strong positive correlation between fasting plasma glucose level and estimated average blood glucose levels (r=0.54, p=0.0001 was observed. The difference was statistically significant. Conclusion: Reporting the estimated average glucose level together with the HbA1c level is believed to assist patients and doctors determine the effectiveness of blood glucose control measures.

Raja Reddy P

2013-03-01

384

Glucose promotes its own metabolism by acting on the cell-surface glucose-sensing receptor T1R3.  

Science.gov (United States)

A homodimer of taste type 1 receptor 3 (T1R3) functions as a sweet taste-sensing receptor in pancreatic ?-cells. This receptor is activated by various sweet molecules including sugars such as glucose. To determine the role of this receptor in glucose-induced insulin secretion, we addressed whether or not this receptor modulates glucose metabolism in MIN6 cells. We measured changes in intracellular ATP ([ATP]i) in MIN6 cells expressing luciferase. Sucralose, an agonist of T1R3, induced immediate and sustained elevation of [ATP]i in the presence of 5.5 mM glucose. The effect of sucralose was dose-dependent and, at 5 mM, was greater than that induced by 25 mM glucose. In contrast, carbachol, GLP-1 or high concentration of potassium did not reproduce the sucralose action. Sucralose facilitated the increase in [ATP]i induced by a mitochondrial fuel methylsuccinate, and potentiated glucose-induced elevation of [ATP]i. Administration of a non-metabolizable glucose analogue, 3-O-methylglucose, which acts as an agonist of T1R3, induced a small and transient increase in [ATP]i. 3-O-Methylglucose augmented elevation of [ATP]i induced by methylsuccinate, and also enhanced glucose-induced increase in [ATP]i. Knock down of T1R3 by using shRNA attenuated [ATP]i-response to high concentration of glucose and also reduced the glucose-induced insulin secretion. These results indicate that activation of the homodimer of T1R3 facilitates the metabolic pathway in mitochondria and augments ATP production. The results obtained by using 3-O-methylglucose suggest that glucose, by acting on the homodimer of T1R3, promotes its own metabolism. PMID:24200979

Nakagawa, Yuko; Ohtsu, Yoshiaki; Nagasawa, Masahiro; Shibata, Hiroshi; Kojima, Itaru

2014-01-01

385

Stable-label intravenous glucose tolerance test minimal model  

International Nuclear Information System (INIS)

The minimal model approach to estimating insulin sensitivity (Sl) and glucose effectiveness in promoting its own disposition at basal insulin (SG) is a powerful tool that has been underutilized given its potential applications. In part, this has been due to its inability to separate insulin and glucose effects on peripheral uptake from their effects on hepatic glucose inflow. Prior enhancements, with radiotracer labeling of the dosage, permit this separation but are unsuitable for use in pregnancy and childhood. In this study, we labeled the intravenous glucose tolerance test (IVGTT) dosage with [6,6-2H2]glucose, [2-2H]glucose, or both stable isotopically labeled glucose tracers and modeled glucose kinetics in six postabsorptive, nonobese adults. As previously found with the radiotracer model, the tracer-estimated S*l derived from the stable-label IVGTT was greater than Sl in each case except one, and the tracer-estimated SG* was less than SG in each instance. More importantly, however, the stable-label IVGTT estimated each parameter with an average precision of +/- 5% (range 3-9%) compared to average precisions of +/- 74% (range 7-309%) for SG and +/- 22% (range 3-72%) for Sl. In addition, because of the different metabolic fates of the two deuterated tracers, there were minor differences in basal insulin-derived measures of glucose effectiveness, but these differences were negligible for parameters describing insulin-stimulated procemeters describing insulin-stimulated processes. In conclusion, the stable-label IVGTT is a simple, highly precise means of assessing insulin sensitivity and glucose effectiveness at basal insulin that can be used to measure these parameters in individuals of all ages, including children and pregnant women

386

In vivo blood glucose quantification using Raman spectroscopy.  

Science.gov (United States)

We here propose a novel Raman spectroscopy method that permits the noninvasive measurement of blood glucose concentration. To reduce the effects of the strong background signals produced by surrounding tissue and to obtain the fingerprint Raman lines formed by blood analytes, a laser was focused on the blood in vessels in the skin. The Raman spectra were collected transcutaneously. Characteristic peaks of glucose (1125 cm(-1)) and hemoglobin (1549 cm(-1)) were observed. Hemoglobin concentration served as an internal standard, and the ratio of the peaks that appeared at 1125 cm(-1) and 1549 cm(-1) peaks was used to calculate the concentration of blood glucose. We studied three mouse subjects whose blood glucose levels became elevated over a period of 2 hours using a glucose test assay. During the test, 25 Raman spectra were collected transcutaneously and glucose reference values were provided by a blood glucose meter. Results clearly showed the relationship between Raman intensity and concentration. The release curves were approximately linear with a correlation coefficient of 0.91. This noninvasive methodology may be useful for the study of blood glucose in vivo. PMID:23133555

Shao, Jingwei; Lin, Manman; Li, Yongqing; Li, Xue; Liu, Junxian; Liang, Jianpin; Yao, Huilu

2012-01-01

387

Regional differences in adipocyte lactate production from glucose  

International Nuclear Information System (INIS)

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-14C]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 esenteric adipocytes may provide a unique and more direct contribution of metabolic substrates for hepatic metabolism than adipocytes from other depots

388

Stimulation of glucose phosphorylation by fructose in isolated rat hepatocytes.  

Science.gov (United States)

The phosphorylation of glucose was measured by the formation of [3H]H2O from [2-3H]glucose in suspensions of freshly isolated rat hepatocytes. Fructose (0.2 mM) stimulated 2-4-fold the rate of phosphorylation of 5 mM glucose although not of 40 mM glucose, thus increasing the apparent affinity of the glucose phosphorylating system. A half-maximal stimulatory effect was observed at about 50 microM fructose. Stimulation was maximal 5 min after addition of the ketose and was stable for at least 40 min, during which period 60% of the fructose was consumed. The effect of fructose was reversible upon removal of the ketose. Sorbitol and tagatose were as potent as fructose in stimulating the phosphorylation of 5 mM glucose. D-Glyceraldehyde also had a stimulatory effect but at tenfold higher concentrations. In contrast, dihydroxyacetone had no significant effect and glycerol inhibited the detritiation of glucose. Oleate did not affect the phosphorylation of glucose, even in the presence of fructose, although it stimulated the formation of ketone bodies severalfold, indicating that it was converted to its acyl-CoA derivative. These results allow the conclusion that fructose stimulates glucokinase in the intact hepatocyte. They also suggest that this effect is mediated through the formation of fructose 1-phosphate, which presumably interacts with a competitive inhibitor of glucokinase other than long-chain acyl-CoAs. PMID:2917559

Van Schaftingen, E; Vandercammen, A

1989-01-15

389

Blood glucose monitoring: an overview.  

Science.gov (United States)

Glucose monitoring is done to obtain information on blood glucose levels to ensure a therapeutic regimen; the aim is to maintain consistent glucose levels and avoid hypoglycaemia and hyperglycaemia. Self-management is central to diabetes control. Diabetes is individual, so self-monitoring of blood glucose (SMBG) targets and frequency of testing must be decided to meet each patient's needs. Nurses have key roles in education and advocacy. They can educate patients on what affects glucose levels, why they need to carry out SMBG, and how to interpret and act on the results. Nurses also match glucose monitoring meters to patients' needs by considering ease of use, technical features and lifestyle. Access to testing supplies is sometimes restricted through blanket policies and nurses have an advocacy role here in challenging inappropriate restrictions. PMID:22875293

Whitmore, Catherine

390

Methodology of effective glucose-specific signal extraction in complicated sample  

Science.gov (United States)

In the area of noninvasive human blood glucose concentration detecting, it has always been a critical task to extract the glucose-specific signal from the highly overlapped and disturbed near-infrared spectrum. In this paper, the methodology of effective glucose-specific signal extraction in complicated non-scattering sample is studied. By analyzing the impact of water displacement upon dissolution of glucose, the relationship between glucose concentration and absorption coefficient of the sample is deduced. Then, the reference wavelength where the absorption coefficient is insensitive to the changes of glucose concentration is put forward theoretically. Accordingly, the validating experiments in aqueous glucose solutions are executed. Both the theoretical and laboratorial results show that the reference wavelength of glucose appears at 1525nm. Based on the reference wavelength, an effective method for extracting the glucose-specific signal in complicated non-scattering samples is proposed and the corresponding validating experiments are constructed with different glucose and albumin concentration. Two different methods, traditional and the novel reference wavelength method are used to extract glucose signal and the corresponding root mean square error of prediction are 19.86mg/dl and 9.87mg/dl respectively. The experiment results indicate that the reference wavelength method can effectively eliminate the influence of various noises on the glucose-specific signal extraction, and thus can remarkably improve the measuring precision in noninvasive near-infrared glucose detecting.

Chen, Wenliang; Deng, Bin; Liu, Rong; Gu, Xiaoyu; Xu, Kexin

2007-02-01

391

Continuous glucose monitoring in interstitial subcutaneous adipose tissue and skeletal muscle reflects excursions in cerebral cortex  

DEFF Research Database (Denmark)

Continuous glucose monitoring (CGM) is being explored using several types of glucose sensors. Some are designed for subcutaneous adipose tissue. It is important to determine to which extent these glucose fluctuations in different tissues reflect changes taking place in the central nervous system, where glucose sensing is thought to occur. We studied the ability of subcutaneous adipose interstitial fluid measurements to parallel glucose propagations in blood, muscle, and central nervous system (CNS) during hyper- and hypoglycemia. A subcutaneous CGM system was applied in the CNS, subcutaneous adipose tissue, and skeletal muscle of nine Vietnamese potbellied pigs, and data were compared with frequent sampling in blood. Alterations in glucose levels were induced with intravenous glucose and insulin. During hyperglycemia, no difference was detected in delay between blood and interstitial glucose levels in subcutaneous adipose tissue (18.0 +/- 0.8 min), muscle (18.0 +/- 0.9 min), and CNS (20.3 +/- 1.2 min), respectively. During hypoglycemia, we found no time difference between interstitial parameters in the three tissues. However, the amplitude of glucose changes varied considerably, with a smaller magnitude of glucose change taking place in the brain. The timing of glucose excursions in subcutaneous adipose tissue and muscle reflect excursions in CNS. The reduced magnitude of glucose excursions in the brain suggests that different mechanisms of glucose transport are operative in CNS compared with subcutaneous adipose tissue and muscle.

Nielsen, Jannik Kruse; Djurhuus, Christian Born

2005-01-01

392

Insulin Induces an Increase in Cytosolic Glucose Levels in 3T3-L1 Cells with Inhibited Glycogen Synthase Activation  

Directory of Open Access Journals (Sweden)

Full Text Available Glucose is an important source of energy for mammalian cells and enters the cytosol via glucose transporters. It has been thought for a long time that glucose entering the cytosol is swiftly phosphorylated in most cell types; hence the levels of free glucose are very low, beyond the detection level. However, the introduction of new fluorescence resonance energy transfer-based glucose nanosensors has made it possible to measure intracellular glucose more accurately. Here, we used the fluorescent indicator protein (FLIPglu-600µ to monitor cytosolic glucose dynamics in mouse 3T3-L1 cells in which glucose utilization for glycogen synthesis was inhibited. The results show that cells exhibit a low resting cytosolic glucose concentration. However, in cells with inhibited glycogen synthase activation, insulin induced a robust increase in cytosolic free glucose. The insulin-induced increase in cytosolic glucose in these cells is due to an imbalance between the glucose transported into the cytosol and the use of glucose in the cytosol. In untreated cells with sensitive glycogen synthase activation, insulin stimulation did not result in a change in the cytosolic glucose level. This is the first report of dynamic measurements of cytosolic glucose levels in cells devoid of the glycogen synthesis pathway.

Helena H. Chowdhury

2014-10-01

393

Insulin induces an increase in cytosolic glucose levels in 3T3-L1 cells with inhibited glycogen synthase activation.  

Science.gov (United States)

Glucose is an important source of energy for mammalian cells and enters the cytosol via glucose transporters. It has been thought for a long time that glucose entering the cytosol is swiftly phosphorylated in most cell types; hence the levels of free glucose are very low, beyond the detection level. However, the introduction of new fluorescence resonance energy transfer-based glucose nanosensors has made it possible to measure intracellular glucose more accurately. Here, we used the fluorescent indicator protein (FLIPglu-600µ) to monitor cytosolic glucose dynamics in mouse 3T3-L1 cells in which glucose utilization for glycogen synthesis was inhibited. The results show that cells exhibit a low resting cytosolic glucose concentration. However, in cells with inhibited glycogen synthase activation, insulin induced a robust increase in cytosolic free glucose. The insulin-induced increase in cytosolic glucose in these cells is due to an imbalance between the glucose transported into the cytosol and the use of glucose in the cytosol. In untreated cells with sensitive glycogen synthase activation, insulin stimulation did not result in a change in the cytosolic glucose level. This is the first report of dynamic measurements of cytosolic glucose levels in cells devoid of the glycogen synthesis pathway. PMID:25279585

Chowdhury, Helena H; Kreft, Marko; Jensen, Jørgen; Zorec, Robert

2014-01-01

394

Glucose Emergencies: Recognition and Treatment  

OpenAIRE

Millions of Americans have pathologies related to glucose regulation. Many of these individuals have diagnosed diabetes. There are, however, countless others who are unaware that they have glucose regulation disorders. Athletic trainers may find themselves called upon to work with individuals with documented and undocumented disorders. The purpose of this article is to define three primary glucose emergencies (diabetic ketoacidosis, diabetic hyperosmolar state, and hypoglycemia) and discuss t...

Martin, David E.

1994-01-01

395

Quantitation of the pathways of hepatic glycogen formation on ingesting a glucose load  

International Nuclear Information System (INIS)

Diflunisal, 5-(2',4'-difluorophenyl)salicylic acid, excreted in urine as its glucuronide, was given to normal humans (n = 6) along with a glucose load specifically labeled with 14C. Glucuronide excreted by each subject was reduced to its glucoside and glucose from it degraded to yield the distribution of 14 C in its six carbons. Randomization of the 14C from the specifically labeled glucose was taken as a measure of the extent to which glucose was deposited indirectly (i.e., glucose----lactate----glucose----6-P----glycogen), rather than directly (i.e., glucose----glucose-6-P----glycogen). The maximum contribution to glycogen formation by the direct pathway was estimated to be 65 +/- 1%, on the assumption that glucuronide and glycogen are derived from the same hepatic pool of glucose-6-P in liver. Evidence that supports that assumption was obtained by comparing the randomization of 14C in the urinary glucuronide with that in glucose in blood from the hepatic vein of four of the subjects before and after they were given glucagon. Other evidence supporting the assumption was obtained by comparing in two subjects 3H/14C ratios in glucose from hepatic vein blood before and after glucagon administration with that in urinary glucuronide, having labeled the uridine diphosphate (UDP)-glucose in their livers with 14C by giving them 1-[14C]galactose and their circulating glucose with 3H by girculating glucose with 3H by giving a 5-[3H]glucose-labeled load. It is concluded that glucuronide formation in humans can be used to trace glucose metabolism in the liver, and that in humans the indirect pathway of glucose metabolism is active

396

Estimation of insulin sensitivity and glucose clearance from minimal model: new insights from labeled IVGTT  

International Nuclear Information System (INIS)

The ''minimal model'' of glucose disappearance provides noninvasive estimates of insulin sensitivity and glucose effectiveness from an intravenous glucose tolerance test (IVGTT). However, this model does not allow the separation of glucose production from utilization. To overcome this limitation, labeled glucose was injected along with cold glucose in six normal dogs, and both cold and labeled glucose time courses were monitored along with insulin concentration. A revised minimal model was fitted to tracer data to obtain new measures of insulin sensitivity (SI* = 6.41 +/- 0.91 10(-4) min-1 X microU-1 X ml-1) and fractional glucose clearance (SG* = 0.0092 +/- 0.0009 min-1). SG* was compared with a direct measure obtained by a hepatic arterial-venous difference technique, which yielded a value of 0.0097 +/- 0.0002, virtually identical to SG*, thereby validating the model estimate. When the original minimal model was identified from cold data, we obtained S1 = 4.52 +/- 1.39 and SG = 0.042 +/- 0.009. SI* and SG* were different from SI and SG, respectively. In particular SG overestimates fractional glucose clearance by approximately five times. The revised minimal model yields glucose disposal parameters SI* and SG* that are not affected by the confounding effect of insulin and glucose inhibition of glucose production. Limitations inherent in cold IVGTT and original minimal model are overcome by labeled IVGTT and the revised minimal model, while test simplicity remainsl model, while test simplicity remains

397

Glucose metabolism in ischemic myocardium  

International Nuclear Information System (INIS)

We determined the myocardial metabolic rate for glucose (MMRGlc) in the ischemic or infarcted myocardium using 18-F-fluorodeoxyglucose (18-FDG) with positron emission tomography (PET), and studied energy metabolism in the ischemic myocardium. In some cases, we compared glucose metabolism images by 18-FDG with myocardial blood flow images using 15-oxygen water. Two normal subjects, seven patients with myocardial infarction and four patients with angina pectoris were studied. Coronary angiography was performed within two weeks before or after the PET study to detect ischemic areas. PET studies were performed for patients who did not eat for 5 to 6 hours after breakfast. Cannulation was performed in the pedal artery to measure free fatty acid, blood sugar, and insulin. After recording the transmission scan for subsequent correction of photon attenuation, blood pool images were recorded for two min. after the inhalation of carbon monoxide (oxygen-15) which labeled the red blood cells in vivo. After 20 min., oxygen-15 water (15 to 20 mCi) was injected for dynamic scans, and flow images were obtained. Thirty min. after this procedure, 18-FDG (5 to 6 mCi) was injected, and 60 min later, a static scan was performed and glucose metabolism images were obtained. Arterial blood sampling for the time activity curve of the tracer was performed at the same time. According to the method of Phelps et al, MMRGlc was calculated in each of the region of interest (ROI) which was located igion of interest (ROI) which was located in the left ventricular wall. MMRGlc obtained from each ROI was 0 to 17 mg/100 ml/min. In normal subjects MMRGlc was 0.4 to 7.3 mg/100 ml/min. In patients with myocardial infarction, it ranged from 3 to 5 mg/100 ml/min in the infarcted lesion. In patients with angina pectoris and subendocardial infarction, MMRGlc was 7 to 17 mg/100 ml/min in the ischemic lesion. In this lesion, myocardial blood flow was relatively low by oxygen-15 imagings (so-called mismatch). (J.P.N.)

398

Effect of repaglinide on endothelial dysfunction during a glucose tolerance test in subjects with impaired glucose tolerance  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Impaired glucose tolerance (IGT is associated with increased cardiovascular risk. The pathophysiological mechanisms linking post-challenge hyperglycemia to accelerated atherosclerosis, however remain to be elucidated. Methods A prospective, open, randomised, cross-over study was performed to investigate the effect of 2 mg repaglinide on hyperglycemia and endothelial function during an oral glucose tolerance test (75 g glucose in 12 subjects with diagnosed IGT. Blood samples for determination of plasma glucose were drawn fasting, 1 and 2 hours after glucose ingestion. Endothelial function was assessed by measuring flow-mediated dilatation (FMD of the brachial artery with high-resolution ultrasound. Results Administration of repaglinide resulted in a significant reduction of plasma glucose at 2 hours (172.8+/-48.4 vs. 138.3+/-41.2 mg/dl; p Conclusion In subjects with IGT, the endothelial dysfunction observed after a glucose challenge is related to the extent of hyperglycemia. Reduction of hyperglycemia by repaglinide reduces endothelial dysfunction in a glucose dependent manner.

Wascher Thomas C

2006-04-01

399

Pentagastrin analogs containing ?-aminooxy acids  

International Nuclear Information System (INIS)

Two 14C-labelled pentagastrin analogs of different specific radioactivities, containing ?-aminooxy acids, have been synthesised to study their biological effects in the gastro-intestinal tract. (U.K.)

400

A portable instrument for continuous glucose monitoring by the integration of microfluidic chip and micro-glucose sensor  

Science.gov (United States)

Interstitial fluid (ISF) can be transdermally extracted using low-frequency ultrasound and continuous vacuum pressure on skin surface. But the tiny volume of transdermally extracted ISF makes the transdermal extraction, collection, transport, volumetric detection and glucose concentration measurement of the ISF very difficult. Based on a microfluidic chip for transdermally extraction of interstitial fluid and a micro glucose sensor for glucose concentration measurement, a continuous glucose monitoring instrumentby ISF transdermal extraction with minimally invasive way is developed. In the paper, various parts of the device and their interface circuits are designed; the hardware and software of the instrument are built; the simulating experiments of transdermal ISF extraction, collection and volume measurement with full-thickness pig skin are performed using this integrated system; and the functionalities of this device is verified for future clinical application.

Li, Dachao; Ji, Yongjie; Liang, Wenshuai; Zhang, Xiaoli; Yu, Haixia; Xu, Kexin

2013-03-01

401

High-speed analog CMOS pipeline system  

International Nuclear Information System (INIS)

We present a switched-capacitor readout system for high speed analog signals. It consists of a 10 MHz four-channel delay-line chip with 58 samples per channel and a 12 channel buffer chip with a sampling rate of 1 MHz and a depth of nine samples. In addition the buffer chip includes an analog multiplexer with 25 inputs for the buffer channels and for 13 additional unbuffered signals. Both chips have been fabricated in CMOS-technology and will be used for the readout of the ZEUS high resolution calorimeter. The circuit and chip concept will be presented and some design optimizations will be discussed. Measurements from integrated prototypes will be given including some experimental data from irradiated chips. (orig.)

402

Evaluation of a double-tracer autoradiographic technique for the measurement of both local cerebral glucose metabolism and local cerebral blood flow  

International Nuclear Information System (INIS)

A solvent washout technique is evaluated that could be used to remove one 14C tracer after a combined autoradiographic CMRglu and CBF study using [14C]2-deoxyglucose (2DG) and [14C]iodoantipyrine (IAP). The technique permits the simultaneous measurement of local CBF and local CMRglu in the same animal without the use of the short-lived tracers of iodine, 123I and 131I, for iodoantipyrine labeling. This report shows that brain tissue sections did not retain 14C from [14C]2DG when chloroform was used as the washout solvent. Chloroform washing removes nearly all the 14C from [14C]IAP. For this study, careful attention was given to the control, prewash measurement of 14C concentration

403

An ozone budget for the UK: using measurements from the national ozone monitoring network; measured and modelled meteorological data, and a 'big-leaf' resistance analogy model of dry deposition  

Energy Technology Data Exchange (ETDEWEB)

A method of calculating a mass budget for O{sub 3} in the UK boundary layer is presented which shows that the spatial scale of the UK is small relative to the footprint of the atmosphere influenced by UK emissions. - Data from the UK national air-quality monitoring network are used to calculate an annual mass budget for ozone (O{sub 3}) production and loss in the UK boundary layer during 1996. Monthly losses by dry deposition are quantified from 1 kmx1 km scale maps of O{sub 3} concentration and O{sub 3} deposition velocities based on a 'big-leaf' resistance analogy. The quantity of O{sub 3} deposition varies from {approx}50 Gg-O{sub 3} month{sup -1} in the winter to over 200 Gg-O{sub 3} month{sup -1} in the summer when vegetation is actively absorbing O{sub 3}. The net O{sub 3} production or loss in the UK boundary layer is found by selecting days when the UK is receiving 'clean' Atlantic air from the SW to NW. In these conditions, the difference in O{sub 3} concentration observed at Mace Head and a rural site on the east coast of the UK indicates the net O{sub 3} production or loss within the UK boundary layer. A simple box model is then used to convert the concentration difference into a mass. The final budget shows that for most of the year the UK is a net sink for O{sub 3} (-25 to -800 Gg-O{sub 3} month{sup -1}) with production only exceeding losses in the photochemically active summer months (+45 Gg-O{sub 3} month{sup -1})

Coyle, M.; Smith, R.; Fowler, D

2003-05-01

404

Importance of the pre-analytical phase in blood glucose analysis.  

Science.gov (United States)

Blood glucose levels are characterized by a relatively large intra-individual biological variability due to food intake, physical activity and the body's homeostatic response. Careful attention to the pre-analytical phase is essential to ensure accurate glucose measurements. Blood samples should be drawn in the morning after an overnight fast. Proper sample processing after blood collection is crucial. When fast separation of the cells is not possible, blood should be collected into a tube containing a glucose preservative. Glucose concentrations may also differ according to the blood sampling site (venous, arterial or capillary blood). Plasma and whole blood glucose values are not interchangeable. The International Federation of Clinical Chemistry and Laboratory Medicine recommends reporting the glucose concentration in plasma to avoid clinical misinterpretations irrespective of the sample type and method of measurement. Point-of-care testing (POCT) glucose meters are widely used by both health professionals and diabetic patients to monitor blood glucose levels. However, one should take into account that the reliability of POCT glucose measurements depends upon a variety of factors including underlying disease, patient drug regimens and interfering substances as well as instrument analytical performance and user proficiency. It is recommended to perform a laboratory blood glucose analysis if the POCT glucose value is in the critical hypoglycaemic or hyperglycaemic range. PMID:21128557

Janssen, K; Delanghe, J

2010-01-01

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