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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 four-parameter fitting of brief dynamic scan sequences in studies of metabolic rate using 2-deoxy-2-fluoroglucose

2

Optoelectronic Apparatus Measures Glucose Noninvasively  

Science.gov (United States)

An optoelectronic apparatus has been invented as a noninvasive means of measuring the concentration of glucose in the human body. The apparatus performs polarimetric and interferometric measurements of the human eye to acquire data from which the concentration of glucose in the aqueous humor can be computed. Because of the importance of the concentration of glucose in human health, there could be a large potential market for instruments based on this apparatus.

Ansari, Rafat R.; Rovati, Luigi L.

2003-01-01

3

Delivery rate affects uptake of a fluorescent glucose analog in murine metastatic breast cancer.  

Science.gov (United States)

We demonstrate an optical strategy using intravital microscopy of dorsal skin flap window chamber models to image glucose uptake and vascular oxygenation in vivo. Glucose uptake was imaged using a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). SO2 was imaged using the differential absorption properties of oxygenated [HbO2] and deoxygenated hemoglobin [dHb]. This study was carried out on two sibling murine mammary adenocarcinoma lines, 4T1 and 4T07. 2-NBDG uptake in the 4T1 tumors was lowest when rates of delivery and clearance were lowest, indicating perfusion-limited uptake in poorly oxygenated tumor regions. For increasing rates of delivery that were still lower than the glucose consumption rate (as measured in vitro), both 2-NBDG uptake and the clearance rate from the tumor increased. When the rate of delivery of 2-NBDG exceeded the glucose consumption rate, 2-NBDG uptake decreased with any further increase in rate of delivery, but the clearance rate continued to increase. This inflection point was not observed in the 4T07 tumors due to an absence of low delivery rates close to the glucose consumption rate. In the 4T07 tumors, 2-NBDG uptake increased with increasing rates of delivery at low rates of clearance. Our results demonstrate that 2-NBDG uptake in tumors is influenced by the rates of delivery and clearance of the tracer. The rates of delivery and clearance are, in turn, dependent on vascular oxygenation of the tumors. Knowledge of the kinetics of tracer uptake as well as vascular oxygenation is essential to make an informed assessment of glucose demand of a tumor. PMID:24204635

Rajaram, Narasimhan; Frees, Amy E; Fontanella, Andrew N; Zhong, Jim; Hansen, Katherine; Dewhirst, Mark W; Ramanujam, Nirmala

2013-01-01

4

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, the loss of [11C]CO2 was substantially delayed and the contrast between gray and white matter was improved

5

Cancer detection by F-18 fluorinated glucose analogs  

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 transplanted rat and rabbit tumors. Tissue distribution studies of rat showed high tumor uptake and low normal tissue uptakes of the the radiopharmaceuticals. Autoradiograms of the whole rats also showed high tumor radioactivity. Positron emission tomography of rabbit tumor delineated clearly the tumor and metastatic lymphnodes. These data showed that both agents were excellent cancer diagnostic agents

6

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

7

Glucose measurements. A 1977 CAP Survey analysis.  

Science.gov (United States)

An anlysis of the 1977 College of American Pathologists (CAP) Comprehensive Chemistry Survey program for glucose measurements is presented. Based on average mean concentrations compared with all-method mean concentration, hexokinase methods are the most accurate. Glucose oxidase-oxygen rate methods demonstrate the best precision in interlaboratory comparison statistics. Neocuproine methods for glucose manifest unacceptable positive biases when compared with overall mean concentrations and other methods. Accuracy and precision indices for glucose measurements in urine are well below those obtained in serum. Again, redox methods, such as those based on neocuproine and ferricyanide, perform so poorly that they should be eliminated. PMID:474511

Sheiko, M C; Burkhardt, R T; Batsakis, J G

1979-08-01

8

Comparability of venous and capillary glucose measurements in blood  

DEFF Research Database (Denmark)

Diabetes and glucose intolerance are diagnosed by measurement of glucose in blood. Glucose is usually measured as venous plasma or capillary whole blood and diagnostic criteria frequently provide equivalence estimates for these two methods. This study examined the relationship between glucose measured in capillary and venous samples collected at random, fasting and 2 h after oral glucose.

Colagiuri, S; Sandbaek, A

2003-01-01

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

Non-Invasive Optical Blood Glucose Measurement  

Directory of Open Access Journals (Sweden)

Full Text Available The method for noninvasively blood glucose monitoring system is discussed in this paper. Lot of research work has been done in developing the device which is completely noninvasive to avoid the pros & cons because of frequent pricking. In this paper we are trying to analyze the noninvasive blood glucose measurement study in the near infrared region which is the most suitable region for blood glucose measurement. For this purpose we use a technique which is similar to pulseoximetry based on near infrared spectrometry .An infrared light of particular wavelength is passed through fingertip containing an arterial pulse component are derived,thus minimizing influences of basal components such as resting blood volume,skin, muscle and bone.

Megha C.Pande

2013-07-01

11

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

12

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

13

Automation of glucose measurement in fermentor broths  

Energy Technology Data Exchange (ETDEWEB)

A semi-on-line automated analysis for fermentation is presented. The system consists of a modified commerical biosensor analyser YSI 27 and a Gilson dilutor injector. The results of direct glucose monitoring in fermentation broths are presented. Measurements, calibrations and washes are completely automated, with a maximum analysis frequency of 16 per hour with dilutions. The detection limits are 50 mg/l and 41 g/l with good linearity and a precision of {+-}5%. (orig.).

Lelong, P.; Cellard, H. (Sanofi Elf Bio Recherches, 31 - Labege (France). Fermentation Dept.); Pardo, D.; Cavalie, J.M. (Sanofi Elf Bio Recherches, 31 - Labege (France). Scientific Data Processing)

1991-11-01

14

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

15

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

Energy Technology Data Exchange (ETDEWEB)

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 [{sup 123}I]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 [{sup 125}I]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 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.

Xu Yiming; Choi, S.-R.; Kung, M.-P.; Kung, Hank F. E-mail: kunghf@sunmac.spect.upenn.edu

1999-10-01

16

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 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

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 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

Testing and calibration of analog signal measuring system  

International Nuclear Information System (INIS)

The routes of analog signals for measuring the temperature, amount and pressure of carbon dioxide in the reactor and for measuring the temperature of uranium in fuel elements are described. The manner and results of the measurement of interference voltages on the routes are described and the calculation is shown of the symmetrical RC filter for the suppression of the interference voltages. The measured results and the tests of the MT 100 converter resistance to interference voltages show that when an analog-to-digital converter of this type is used route filtration is unnecessary. (J.B.)

 
 
 
 
21

Fluorescence spectroscopy for noninvasive glucose measurement  

Science.gov (United States)

The interaction between gold nanoparticles and glucose and its effect on the fluorescence spectrum of nanoparticles were investigated experimentally. It was observed after this interaction the intensity of fluorescence peak becomes weaker and red shifted.

Bagheri, Z.; Massudi, R.; Ghanavi, J.; Latifi, H.

2013-06-01

22

Glucose measurement by surface plasmon resonance with borate polymer binding  

Science.gov (United States)

Minimally-invasive human blood glucose detection can be realized by measuring the glucose concentration of interstitial fluid to predict the blood glucose level. As the amount of transdermally extracted interstitial fluid was minimal and its composition was complex, a glucose measurement method by surface plasmon resonance (SPR) based on PAA-ran-PAAPBA polymer binding was proposed. The polymer was immobilized on the gold film of SPR sensor using layer-by-layer self-assembly technique to capture the glucose molecules in interstitial fluid to realize the detection of glucose concentration with high precision. 2~1000mg/dL glucose solutions were measured utilizing the SPR sensor by polymer binding. The fitting degrees were 0.90177 and 0.99509 in the range of 2~10mg/dL and 25~1000mg/dL respectively. The dynamic dissociation process of glucose molecules from PAA-ran-PAAPBA was verified to be able to satisfy the requirements of the human blood glucose continuous monitoring in clinics.

Li, Dachao; Yang, Jia; Wu, Peng; Yang, Di; Wang, Bo; Lin, Yuan; Xu, Kexin

2013-02-01

23

The non-metabolizable glucose analog D-glucal inhibits aflatoxin biosynthesis and promotes kojic acid production in Aspergillus flavus  

Science.gov (United States)

Background Aflatoxins (AFs) are potent carcinogenic compounds produced by several Aspergillus species, which pose serious threats to human health. As sugar is a preferred carbohydrate source for AF production, we examined the possibility of using sugar analogs to inhibit AF biosynthesis. Results We showed that although D-glucal cannot be utilized by A. flavus as the sole carbohydrate source, it inhibited AF biosynthesis and promoted kojic acid production without affecting mycelial growth when applied to a glucose-containing medium. The inhibition occurred before the production of the first stable intermediate, norsolorinic acid, suggesting a complete inhibition of the AF biosynthetic pathway. Further studies showed that exogenous D-glucal in culture led to reduced accumulation of tricarboxylic acid (TCA) cycle intermediates and reduced glucose consumption, indicating that glycolysis is inhibited. Expression analyses revealed that D-glucal suppressed the expression of AF biosynthetic genes but promoted the expression of kojic acid biosynthetic genes. Conclusions D-glucal as a non-metabolizable glucose analog inhibits the AF biosynthesis pathway by suppressing the expression of AF biosynthetic genes. The inhibition may occur either directly through interfering with glycolysis, or indirectly through reduced oxidative stresses from kojic acid biosynthesis. PMID:24742119

2014-01-01

24

Lyoluminescence Measurements of Mannose and Glucose.  

Science.gov (United States)

The lyoluminescence and its possible applications have been studied by several authors and, since their results seem promising, a reading system has been set up and experiments on this phenomenon have been carried out D(+) glucose and D(+) mannose have be...

G. Busuoli, G. Maestri, F. Monteventi

1981-01-01

25

A Bell Inequality Analog in Quantum Measure Theory  

CERN Document Server

One obtains Bell's inequalities if one posits a hypothetical joint probability distribution, or measure, whose marginals yield the probabilities produced by the spin measurements in question. The existence of a joint measure is in turn equivalent to a certain local causality condition known as ``screening off''. We show that if one assumes, more generally, a joint ``quantal measure'', or ``decoherence functional'', one obtains instead an analogous inequality weaker by a factor of sqrt(2). The proof of this ``Tsirel'son inequality'' is geometrical and rests on the possibility of associating a Hilbert space to any strongly positive quantal measure. These results lead both to a question: ``Does a joint measure follow from some quantal analog of `screening off'?'', and to the observation that non-contextual hidden variables are viable in histories-based quantum mechanics, even if they are excluded classically.

Craig, D; Henson, J; Major, S; Rideout, D; Sorkin, R D; Craig, David; Dowker, Fay; Henson, Joe; Major, Seth; Rideout, David; Sorkin, Rafael D.

2006-01-01

26

Adaptation of a manometric biosensor to measure glucose and lactose.  

Science.gov (United States)

A manometric sensor previously developed to measure urea was modified to measure glucose and lactose through enzymatic oxidation. Change in pressure in an enclosed cavity was correlated to the depletion of oxygen resulting from the enzymatic oxidation of glucose or lactose. The response of the sensor was linear and could be made adjustable over a large range by adjusting the amount of sample loaded into the fixed volume reactor. Because of the slow mutarotation of glucose, the oxidation of glucose was not allowed to proceed to completion. Therefore, the precision of the sensor (approximately 0.2 mM in a range from 0 to 5 mM) was limited by variations in the oxidation rate of glucose by glucose oxidase. Because the assay for lactose measured glucose subsequent to the hydrolysis of lactose by beta-galactosidase, the same degree of precision was observed in lactose. Milk lactose, typically at concentrations of about 150 mM, was estimated using the lactose assay after first diluting the samples. For many fluids such as milk, the use of manometric sensors for oxidizable substrates may be preferable to optical and electrochemical methods because they are robust and suffer a low degree of optical and chemical interferences. Glucose and lactose are representative of many important oxidizable substrates, which may be determined in this manner, many of which do not suffer from limitations caused by mutarotation. In theory, detection limits less than 1 microM may be achieved using these methods. PMID:12445450

Jenkins, Daniel M; Delwiche, Michael J

2003-01-01

27

A flexible and wearable biosensor for tear glucose measurement.  

Science.gov (United States)

A flexible and wearable amperometoric glucose sensor was fabricated and tested. Also, the sensor was utilized to tear glucose monitoring. The sensor was constructed by immobilizing GOD onto a flexible oxygen electrode (Pt working electrode and Ag/AgCl counter/reference electrode), which was fabricated using "Soft-MEMS" techniques onto a functional polymer membrane. In purpose of bioinstrumentation, adhesive agents were not used for constructing the flexible biosensor. Linear relationship between glucose concentration and output current was obtained in a range of 0.025-1.475 mmol/l, with a correlation coefficient of 0.998. Current dependences on pH and temperature were also evaluated. The current was largest at pH 7.0 and the current increased when temperature increased. This indicates that the output current depends on enzyme activity. Based on the basic characteristics investigation, the glucose sensor was applied to measurement of glucose in tear fluids on an eye site of a Japan white rabbit. The change of tear glucose level induced by oral-administration of glucose was monitored as a current change of the sensor attached on the eye site. In this investigation, the tear glucose level varied from 0.16 to 0.46 mmol/l. Although there was a delay of several tens of minutes towards blood sugar level, it is considered to be possible that non-invasive continuous glucose monitoring can be realized using the flexible biosensor. PMID:17520370

Iguchi, Shigehito; Kudo, Hiroyuki; Saito, Takao; Ogawa, Mitsuhiro; Saito, Hirokazu; Otsuka, Kimio; Funakubo, Akio; Mitsubayashi, Kohji

2007-08-01

28

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

29

A Bell inequality analog in quantum measure theory  

Energy Technology Data Exchange (ETDEWEB)

One obtains Bell's inequalities if one posits a hypothetical joint probability distribution, or measure, whose marginals yield the probabilities produced by the spin measurements in question. The existence of a joint measure is in turn equivalent to a certain causality condition known as 'screening off'. We show that if one assumes, more generally, a joint quantal measure, or 'decoherence functional', one obtains instead an analogous inequality weaker by a factor of {radical}2. The proof of this 'Tsirel'son inequality' is geometrical and rests on the possibility of associating a Hilbert space to any strongly positive quantal measure. These results lead both to a question: 'Does a joint measure follow from some quantal analog of 'screening off'?', and to the observation that non-contextual hidden variables are viable in histories-based quantum mechanics, even if they are excluded classically.

Craig, David [Le Moyne College, Syracuse, New York 13214 (United States); Dowker, Fay [Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom); Henson, Joe [Institute for Theoretical Physics, University of Utrecht, Minnaert Building, Leuvenlaan 4, 3584 CE Utrecht (Netherlands); Major, Seth [Department of Physics, Hamilton College, Clinton, New York 13323 (United States); Rideout, David [Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom); Sorkin, Rafael D [Perimeter Institute, Waterloo, Ontario N2 L 2Y5 (Canada)

2007-01-19

30

Original Method for Non-Invasive Glucose Measurement: Preliminary Results.  

Science.gov (United States)

This paper presents first results obtained using a novel approach for non-invasive measurement of glucose content We use a network analyzer, which is used to measure T/R, the modulus of the Transmission to the Reference signal. The under-test solution is ...

S. M. Alavi, M. Gourzi, A. Rouane, M. Nadi

2001-01-01

31

Measurement and modeling of glucose-6-phosphatase in pancreatic islets.  

Science.gov (United States)

In the beta-cells of the pancreas, glucose phosphorylation carried out by glucokinase is the rate-controlling step in glycolysis, and the kinetic characteristics of glucokinase govern to a high degree the dose-response relationship between glucose and insulin release. Because glucose-6-phosphatase (G-6-Pase) opposes the action of glucokinase, it may have a regulatory role in the release of insulin in response to glucose if the enzyme is present in the beta-cells. A number of researchers have reported finding high levels of G-6-Pase in islets, but quantitation of its activity remains controversial, mainly because of difficulties in solubilizing a particulate enzyme. Therefore a method developed to measure functional glucose phosphorylation activity in intact brain was applied (Chi, M. M.-Y., M. E. Pusateri, J. G. Carter, B. J. Norris, D. B. McDougal, Jr., and O. H. Lowry. Anal. Biochem. 161: 508-513, 1987), and the rates of accumulation and disappearance of 2-deoxyglucose 6-phosphate (DG-6-P) in freshly harvested islets were determined as a measure of glucose cycling. Islets were incubated in the presence of 30 mM 2-deoxyglucose (DG) for 60 min, and subsequently the incubation medium was replaced with medium containing no DG, but instead high levels of mannoheptulose as a blocker of phosphorylation. The content of DG-6-P in the islets was measured at strategic times during the protocol. As predicted by a mathematical model, DG-6-P accumulated in the presence of DG and decayed after its washout. Both of these results are consistent with islets containing dephosphorylation activity for this substrate. The kinetic curves were fit using a mathematical model, and the maximal G-6-Pase activity was estimated to be 0.13 +/- 0.005 micromol x g(-1) x min(-1). However, when the physiological effect of this amount of G-6-Pase activity was assessed by use of a model of glycolysis, it was found that the impact on glucose cycling and usage was insignificant. It was concluded that normal islets do contain measurable activity for dephosphorylating glucose 6-phosphate but that this enzymatic reaction does not play a role in glucose metabolism and sensing by the normal beta-cell. PMID:9142893

Sweet, I R; Najafi, H; Li, G; Grodberg, J; Matschinsky, F M

1997-04-01

32

Glucose production, gluconeogenesis, and hepatic tricarboxylic acid cycle fluxes measured by nuclear magnetic resonance analysis of a single glucose derivative  

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A triple-tracer method was developed to provide absolute fluxes contributing to endogenous glucose production and hepatic tricarboxylic acid (TCA) cycle fluxes in 24-h-fasted rats by 2H and 13C nuclear magnetic resonance (NMR) analysis of a single glucose derivative. A primed, intravenous [3,4-13C2]glucose infusion was used to measure endogenous glucose production; intraperitoneal 2H2O (to enrich total body water) was used to quantify sources of glucose (TCA cycle, glycerol, and glycogen), an...

Jin, Eunsook S.; Jones, John G.; Merritt, Matthew; Burgess, Shawn C.; Malloy, Craig R.; Sherry, A. Dean

2004-01-01

33

A potentially implantable enzyme electrode for amperometric measurement of glucose.  

Science.gov (United States)

A membrane limited amperometric enzyme electrode suitable for glucose measurement in biological fluids was developed. The sensor consists of a central platinum wire (0.3 mm) surrounded by a stainless steel tubing (0.8-1.0 mm outer diameter; 2-4 cm length). By successive dipcoating procedures, layers from cellulose acetate, glucose oxidase (crosslinked with glutaraldehyde) and polyurethane are placed on its surface. The platinum is polarized at +700 mV against steel. In vitro results: Electrodes are stable for at least 6 days. They exhibit a linear range extending to 500 mg/dl glucose. Response times are less than 100 sec. The sensors are not dependent on stirring and are relatively insensitive to changes of pH. Dependency of glucose measurement upon dissolved oxygen is negligible at oxygen concentrations above 0.5 mg/l. In vivo results: Preliminary studies in sheep using subcutaneously implanted needles indicate that short term glucose monitoring is feasible. PMID:3248792

Kerner, W; Zier, H; Steinbach, G; Brückel, J; Pfeiffer, E F; Weiss, T; Cammann, K; Planck, H

1988-01-01

34

Expression of human globular adiponectin-glucagon-like peptide-1 analog fusion protein and its assay of glucose-lowering effect in vivo.  

Science.gov (United States)

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. PMID:21448306

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

2011-01-01

35

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

36

Effects of maternal ethanol ingestion on uptake of glucose alanine analogs in fetal rats  

International Nuclear Information System (INIS)

The distribution of maternally-derived glucose and alanine has been studied in selected tissues of fetuses from ethanol-fed (EF) rats (30% of caloric intake throughout gestation). Controls received diet without ethanol by pair-feeding (PF) or ad libitum (AF). On the 22nd day of gestation, 2 ?Ci 3H 2-deoxyglucose (DG) and 1 ?Ci 14C ?-aminoisobutyric acid (AIB) were administered i.v. to each rat. One hour later, maternal blood, placenta, and fetal blood, liver, lung and brain were sampled for 3H and 14C activities. When compared to either control group, the mean 14C AIB activities of tissues from EF animals were reduced from 19 to 46%, with the greatest effect seen in the brain (3.7 +/- 0.1, 7.2 +/- 0.3 and 6.9 +/- 1.3 dpm/mg in EF, PF and AF fetuses respectively). In addition, the ratios of tissue:plasma 14C were reduced (p 3H 2-DG content of placenta (p < 0.05) and of brain (38.6 + 1.2, 48.1 +/- 1.2 and 47.2 +/- 1.2 in EF, PF and AF, p < 0.001). Brain weight showed significant positive correlations with AIB content (r = 0.466, p < 0.001) and with 2-DG content (r = 0.267, p < 0.01). Impaired uptake of maternally-derived nutrients may play a significant role in the effects of ethanol in utero

37

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

38

A New Digit Positioning Method for Analog Measuring Instruments  

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Full Text Available For the automatic digit positioning of analogy measuring instruments, a positioning method based on coordinate transformation which has practical application is brought forward. And for the present, the mostly used ways for this field are method based on Hough transform and method based on circle scanning. But they have some defects such as time-consuming and complex or low accuracy rate. The method in this study is proposed to solve the above problems. It is primarily based on the coordinate transformation and projection operation to realize the object of digit positioning. By experiment, the validity and feasibility of the positioning method based on coordinate transformation are confirmed. It is shown that the average accuracy is improved by 5.4% and average positioning efficiency is improved by 8.73% compared to the present methods.

Zhenhua Wei

2013-04-01

39

Blood glucose measurement by using hollow optical fiber-based attenuated total reflection probe.  

Science.gov (United States)

A noninvasive glucose monitoring system based on mid-infrared, attenuated total reflection spectroscopy using a hollow optical fiber probe is developed. Owing to the flexible fiber probe, measurement of oral mucosa, where blood capillaries are near the skin surface, is possible. Blood glucose levels are measured by detecting the peak intensity of glucose absorption bands, and the experimental results showed that the reproducibility of the measurement is high enough for monitoring blood glucose. PMID:24849387

Kino, Saiko; Tanaka, Yuki; Matsuura, Yuji

2014-05-01

40

Investigation of (/sup 18/F)2-fluoro-2-deoxyglucose for the measure of myocardial glucose metabolism  

Energy Technology Data Exchange (ETDEWEB)

Fluorine-18-labeled 2-deoxyglucose (FDG) was studied as a glucose analog for the measure of myocardial glucose metabolism. Myocardial uptake and retention, blood clearance, species dependence (dog, monkey, man), and effect of diet on uptake were investigated. Normal myocardial uptake of FDG was 3 to 4% of injected dose in dog and monkey, and 1 to 4% in man, compared with brain uptakes of 1.5 to 3% in dog, 5 to 6% in monkey, and 4 to 8% in man. The myocardial metabolic rate (MR) for glucose in the nonfasting (glycolytic) state was 2.8 times that in the fasting (ketogenic) state. Human subjects showed higher myocardial uptake after a normal meal than after a meal containing mostly free fatty acids (FFA). Blood clearance was rapid with initial clearance t/sub 1/2/ of 0.2 to 0.3 min, followed by a t/sub 1/2/ of 8.4 +- 1.2 min in dog and 11.6 +- 1.1 min in man. A small third component had half-times of 59 +- 10 min and 88 +- 4 min in dog and man, respectively. With the ECAT positron tomograph, high image-contrast ratios were found between heart and blood (dog 3.5/1, man 14/1), heart and lung (dog 9/1, man 20/1), and heart and liver (dog 15/1, man 10/1). The FDG was taken up rapidly by the myocardium without any significant tissue clearance over a 4-hr period. The FDG exhibited excellent imaging properties. Average counting rates of 12K, 20K, and 40K c/min-mCi injected are obtained in human subjects with high, medium, and low resolutions of the ECAT tomograph. Determination of glucose and FFA MR in vivo with EACT provides a method for investigation and assessment of changing aerobic and anaerobic metabolic rates in ischemic heart disease in man.

Phelps, M.E.; Hoffman, E.J.; Selin, C.; Huang, S.C.; Robinson, G.; MacDonald, N.; Schelbert, H.; Kuhl, D.E.

1978-12-01

 
 
 
 
41

Measurement of lactate formation from glucose using [6-3H]- and [6-14C]glucose in humans  

International Nuclear Information System (INIS)

To assess the validity of determining the origin of plasma lactate from the ratio of lactate and glucose specific activities (SA) during infusion of labeled glucose, normal subjects received infusions of [6-3H]- and [6-14C]glucose for 4 h after a 12 h fast, and, on another day, cold glucose labeled with both tracers during 4-6 h of hyperinsulinemia (approximately 650 microU/ml). Basally, less lactate was derived from plasma glucose when measured with [6-3H]glucose (27 +/- 2%) than with [6-14C]glucose (40 +/- 2%, P less than 0.001). Insulin did not increase the percent of lactate derived from plasma glucose when measured with [6-3H]glucose (29 +/- 2%) but did increase when measured with [6-14C]glucose (60 +/- 4%). The arterialized blood (A) [3H]lactate SA was 30-40% higher (P less than 0.01) than deep venous blood (V) [3H]lactate SA, whereas A and V [14C]lactate SA were similar. During conversion of alanine to lactate with glutamic-pyruvic transaminase (GPT) and lactate dehydrogenase (LDH) in vitro, 32 +/- 2% of 3H in [3-3H]alanine was found in water and 68 +/- 2% in lactate. During infusion of [6-3H]- and [6-14C]glucose, the ratio of [14C]alanine to lactate SA (0.88 +/- 0.05) was less than the ratio of [3H]alanine to lactate SA (0.31 +/- 0.03, P less than 0.001). In conclusion (1) loss of 3H relative to 14C from position 6 in glucose occurs during lactate formation in extrahepatic tissues possibly due to the GPT reaction (alanine conversion to pyruvate), and (2) even ine conversion to pyruvate), and (2) even under supraphysiologic hyperinsulinemic conditions not all of plasma lactate originates from plasma glucose

42

Multi-channel system for analog signals measuring with intermedite frequency conversion  

International Nuclear Information System (INIS)

A multi-channel system for measuring slowly-changing analog signals intended for operation under noise conditions is described. Measurement is carried out using the method of voltage to pulse repetition period conversion with following measuring this period

43

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

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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

44

Glucose measurement in interstitial fluid by microdialysis for the calibration of minimally invasive blood glucose monitoring  

Science.gov (United States)

According to the requirement of the calibration in minimally invasive blood glucose monitoring, a method based on microdialysis was presented to monitor glucose level in interstitial fluid continuously. An experimental system simulating the continuous change of glucose concentration in vivo was built. The influences on recovery of microdialysis caused by flow rate, glucose concentration, and temperature etc. were studied. The results led to the conclusion that the recovery fell by 71.7% when perfusion rate increased from 0.3 ?L/min to 3.0 ?L/min, while the different concentrations of glucose solutions scarcely contribute to the recovery instead, and the temperatures from 25 to 58 °C caused the recovery to increase by 34.6%.

Li, Dachao; Wang, Ridong; Chong, Hao; Liu, Yu; Xu, Kexin

2013-03-01

45

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

46

On-chip Glucose Sensor for Online Measurement of Cell Activities  

Science.gov (United States)

In this study, we developed a cell-based microfluidic device, which is integrated micro-electrochemical sensors, for online measurement of cellular glucose consumption under perfusion culture. Glucose sensors are placed at inlet and outlet of a cell culture chamber. The cellular glucose consumption is measured by comparing concentrations of dissolved glucose in culture medium before and after contact with the cells. As result of our preliminary test, online measurement of the difference of glucose concentration by cells succeeded using the device. We believe that the cell-based microfluidic device can be applied to bio- and medical science.

Kimura, Hiroshi; Shono, Yuki; Pereira-Rodrigues, Nazaré; Yamamoto, Takatoki; Sakai, Yasuyuki; Fujii, Teruo

47

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

48

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

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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

49

Accuracy of point-of-care blood glucose measurements in critically ill patients in shock.  

Science.gov (United States)

A widely used method in monitoring glycemic status of ICU patients is point-of-care (POC) monitoring devices. A possible limitation to this method is altered peripheral blood flow in patients in shock, which may result in over/underestimations of their true glycemic status. This study aims to determine the accuracy of blood glucose measurements with a POC meter compared to laboratory methods in critically ill patients in shock. POC blood glucose was measured with a glucose-1-dehydrogenase-based reflectometric meter. The reference method was venous plasma glucose measured by a clinical chemistry analyzer (glucose oxidase-based). Outcomes assessed were concordance to ISO 15197:2003 minimum accuracy criteria for glucose meters, bias in glucose measurements obtained by the 2 methods using Bland-Altman analysis, and clinical accuracy through modified error grid analysis. A total of 186 paired glucose measurements were obtained. ISO 2003 accuracy criteria were met in 95.7% and 79.8% of POC glucose values in the normotensive and hypotensive group, respectively. Mean bias for the normotensive group was -12.4 mg/dL, while mean bias in the hypotensive group was -34.9 mg/dL. POC glucose measurements within the target zone for clinical accuracy were 90.2% and 79.8% for the normotensive and hypotensive group, respectively. POC blood glucose measurements were significantly less accurate in the hypotensive subgroup of ICU patients compared to the normotensive group. We recommend a lower threshold in confirming POC blood glucose with a central laboratory method if clinically incompatible. In light of recently updated accuracy standards, we also recommend alternative methods of glucose monitoring for the ICU population as a whole regardless of blood pressure status. PMID:25172876

Garingarao, Carlo Jan Pati-An; Buenaluz-Sedurante, Myrna; Jimeno, Cecilia Alegado

2014-09-01

50

Analog measurement of delayed antiproton annihilation time spectra in a high intensity pulsed antiproton beam  

International Nuclear Information System (INIS)

An analog detection system has been developed to measure delayed antiproton annihilation time spectra for laser resonance spectroscopy of metastable antiprotonic helium atoms using the high-intensity pulsed beam of antiprotons from LEAR at CERN. (orig.)

51

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

Energy Technology Data Exchange (ETDEWEB)

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

Ackermann, R.F.; Lear, J.L. (UCLA School of Medicine (USA))

1989-12-01

52

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

Science.gov (United States)

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. PMID:2584274

Ackermann, R F; Lear, J L

1989-12-01

53

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

54

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

Science.gov (United States)

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) C6 ]glucose and [U-(13) C6 , D7 ]glucose, and for glycerol, [U-(13) C3 , D8 ]glycerol was used. The method was validated by means of calibration curves, quality control samples, and plasma samples spiked with [6,6-D2 ]glucose, [U-(13) C6 ]glucose, and [1,1,2,3,3-D5 ]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) C6 ]glucose and r(2) ?=?0.9996 for [U-(13) C6 , D7 ]glucose, and r(2) ?=?0.9995 for the glycerol concentration. Interday accuracy for glucose using [U-(13) C6 ]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. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25303387

Bornø, Andreas; Foged, Lene; van Hall, Gerrit

2014-10-01

55

The use of /sup 11/C-glucose and positron emission tomography to measure brain glucose metabolism  

International Nuclear Information System (INIS)

To measure regional cerebral metabolism of glucose (CMRGlu) with positron emission tomography (PET), but avoid the potential problems inherent in the use of /sup 18/F-fluoro-deoxyglucose, (e.g. regional variation in regional rate constants and instability of the ''lumped constant''), the authors have developed a method using uniformly labeled /sup 11/C-glucose. The method employs a 4-compartment model that accounts for vascular tracer, transport of tracer in and out of the extravascular space, metabolism of tracer, and the production of labeled carbon dioxide, which is free to leave the tissue with blood flow. The differential equations for this model, when solved for CMRGlu, yield CMRGlu=k/sub 1/ . k/sub 3/ . CBF . C/sub B//[k/sub 1/ . k/sub 3/+CBF/CBV . (k/sub 2/+k/sub 3/)] where CBF and CBV are cerebral blood flow and volume, C/sub B/ is unlabeled blood glucose content, k/sub 1/ and k/sub 2/ are transport rate constants and k/sub 3/ is the metabolism rate constant. The authors have begun implementing this technique in baboons and human subjects by first measuring regional CBV and CBF with extant PET methods, then after injection of 20-40mCi of U-/sup 11/C-glucose, estimating the rate constants from 40 sequential PET scans taken over 20 minutes. Resulting white-to-gray matter range in CMRGlu for one typical human subject was 2.9 to 6.3 mg/(min . 100 mg). Oxygen metabolism (CMRO/sub 2/) was also measured at the same sitting with PET and the molar ratio of CMRO/sub 2//CMRGlu ranged from 5.8 to 6.4 as would be expected. These results demonstrate that it may be feasible to avoid the difficulties of an analogue tracer in the measurement of CMRGlu by using /sup 11/C-glucose

56

A novel reagentless sensing system for measuring glucose based on the galactose/glucose-binding protein  

Science.gov (United States)

The galactose/glucose-binding protein (GBP) is synthesized in the cytoplasm of Escherichia coli in a precursor form and exported into the periplasmic space upon cleavage of a 23-amino-acid leader sequence. GBP binds galactose and glucose in a highly specific manner. The ligand induces a hinge motion in GBP and the resultant protein conformational change constitutes the basis of the sensing system. The mglB gene, which codes for GBP, was isolated from the chromosome of E. coli using the polymerase chain reaction (PCR). Since wild-type GBP lacks cysteines in its structure, introducing this amino acid by site-directed mutagenesis ensures single-label attachment at specific sites with a sulfhydro-specific fluorescent probe. Site-directed mutagenesis by overlap extension PCR was performed to prepare three different mutants to introduce a single cysteine residue at positions 148, 152, and 182. Since these residues are not involved in ligand binding and since they are located at the edge of the binding cleft, they experience a significant change in environment upon binding of galactose or glucose. The sensing system strategy is based on the fluorescence changes of the probe as the protein undergoes a structural change on binding. In this work a reagentless sensing system has been rationally designed that can detect submicromolar concentrations of glucose. The calibration plots have a linear working range of three orders of magnitude. Although the system can sense galactose as well, this epimer is not a potential interfering substance since its concentration in blood is negligible. Copyright 2001 Academic Press.

Salins, L. L.; Ware, R. A.; Ensor, C. M.; Daunert, S.

2001-01-01

57

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

58

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

59

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 of glucose metabolism in the newborn period and represent the first direct measurements of new glucose production and utilization in the human neonate

60

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

 
 
 
 
61

Non Invasive Blood Glucose Measurement using NIR technique based on occlusion spectroscopy  

Directory of Open Access Journals (Sweden)

Full Text Available Diabetes is considered to be one of the major health care epidemics of modern era. The determination of blood glucose concentration using the self monitoring blood glucose devices involves the chemical analysis of blood samples taken by pricking the finger or extracting blood from forearm. The pain, discomfort and inconvenience in the current invasive method has led to the feasibility study of noninvasive measurement techniques. In this paper, an optical method using NIR technique based on occlusion spectroscopy is used whichshows that it can be possible to measure glucose concentration in blood non invasively.

Prof..Mrs.A.A.Shinde

2011-12-01

62

Adaptive Blood Glucose Monitoring and Insulin Measurement Devices for Visually Impaired Persons.  

Science.gov (United States)

This article describes devices that people with visual impairments and diabetes can use to monitor blood glucose levels and measure insulin. A table lists devices, their manufacturers (including address and telephone number), and comments about the devices. (DB)

Petzinger, R. A.

1993-01-01

63

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

International Nuclear Information System (INIS)

The nigrostriatal dopaminergic function and glucose metabolism were evaluated in 34 patients with various movement disorders by using positron emission tomography with 18F-Dopa and 18F-FDG respectively. The 18F-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 18F-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 18F-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 18F-Dopa uptake in the striatum increased and the glucose metabolism was normal in cases of idiopathic dystonia. Various patterns of 18F-Dopa uptake and glucose metabolism were thus observed in the various movement disorders. These results suggest that the measurements of the 18F-Dopa uptake and the cerebral glucose metabolism would be useful for the evaluation of the striatal function in various movement disorders. (author)

64

A high sensitivity MEA probe for measuring real time rat brain glucose flux.  

Science.gov (United States)

The mammalian central nervous system (CNS) relies on a constant supply of external glucose for its undisturbed operation. This article presents an implantable Multi-Electrode Array (MEA) probe for brain glucose measurement. The MEA was implemented on Silicon-On-Insulator (SOI) wafer using Micro-Electro-Mechanical-Systems (MEMS) methods. There were 16 platinum recording sites on the probe and enzyme glucose oxidase (GOx) was immobilized on them. The glucose sensitivity of the MEA probe was as high as 489 µA mM(-1) cm(-2). 1,3-Phenylenediamine (mPD) was electropolymerized onto the Pt recording surfaces to prevent larger molecules such as ascorbic acid (AA), 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT), and dopamine (DA) from reaching the recording sites surface. The MEA probe was implanted in the anesthetized rat striatum and responded to glucose levels which were altered by intraperitoneal injection of glucose and insulin. After the in vivo experiment, the MEA probe still kept sensitivity to glucose, these suggested that the MEA probe was reliable for glucose monitoring in brain extracellular fluid (ECF). PMID:24362080

Wei, Wenjing; Song, Yilin; Shi, Wentao; Lin, Nansen; Jiang, Tingjun; Cai, Xinxia

2014-05-15

65

Monitoring glucose in vivo by measuring laser-induced acoustic profiles  

Science.gov (United States)

The optoacoustic method of monitoring absorbed optical energy distribution in tissues was employed to measure changes in glucose concentration in vivo. Glucose osmotic and hydrophilic properties cause reduction of tissue scattering as a result of glucose concentration increase around scattering particles and fibers. The opto-acoustic (OA) method utilizes time-resolved measurements of laser- induced ultrasonic profile in tissue resembling the distribution of absorbed optical energy. This opto-acoustic profile yields effective optical attenuation coefficient, which decreases with decrease of scattering. Glucose effect has been investigated initially in phantoms resembling optical properties of sclera and polystyrene microspheres water solution colored with potassium chromate and then in sclera in vitro and in sclera of live rabbits. The forward mode of opto-acoustic detection was used in the experiments in vitro. Experiments were performed in UV spectral range at the wavelength of (lambda) equals 355-nm. Experimental results demonstrated that an increase in glucose concentration from 5 mM to 60 mM was expressed in the 3 percent reduction of (mu) eff in aqueous solution of polystyrene microspheres. The effect of glucose on sclera in vitro was more prominent and measured as 10 percent reduction of (mu) eff with increase of glucose concentration from 1 mM to 50 mM. It was found that both the amplitude and the profile of OA signal were influenced by mechanical pressure applied to sclera specimen toward the surface of OA transducer. In experiments in live tissue, the backward detection mode was employed, as the only one side access to the tissue surface was available. In experiments in vivo the opto-acoustic profiles were measured in rabbit's sclera before and after intravenous glucose administering. The glucose concentration in rabbit blood was simultaneously measured using commercial device employing chemical analysis of blood. Experimental results demonstrated that a 1 mM increase in glucose concentration resulted in a 3 percent decrease of optical attenuation in rabbit sclera in vivo. Such a pronounced change of optical scattering in sclera in response to physiologic change in blood glucose concentration encourages us to continue measurements in vivo and modeling glucose effect on tissue optics.

Bednov, Andrey A.; Karabutov, Alexander A.; Savateeva, Elena V.; March, Wayne F.; Oraevsky, Alexander A.

2000-05-01

66

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.

67

Measurement of glucose concentration by image processing of thin film slides  

Science.gov (United States)

Measurement of glucose concentration is important for diagnosis and treatment of diabetes mellitus and other medical conditions. This paper describes a novel image-processing based approach for measuring glucose concentration. A fluid drop (patient sample) is placed on a thin film slide. Glucose, present in the sample, reacts with reagents on the slide to produce a color dye. The color intensity of the dye formed varies with glucose at different concentration levels. Current methods use spectrophotometry to determine the glucose level of the sample. Our proposed algorithm uses an image of the slide, captured at a specific wavelength, to automatically determine glucose concentration. The algorithm consists of two phases: training and testing. Training datasets consist of images at different concentration levels. The dye-occupied image region is first segmented using a Hough based technique and then an intensity based feature is calculated from the segmented region. Subsequently, a mathematical model that describes a relationship between the generated feature values and the given concentrations is obtained. During testing, the dye region of a test slide image is segmented followed by feature extraction. These two initial steps are similar to those done in training. However, in the final step, the algorithm uses the model (feature vs. concentration) obtained from the training and feature generated from test image to predict the unknown concentration. The performance of the image-based analysis was compared with that of a standard glucose analyzer.

Piramanayagam, Sankaranaryanan; Saber, Eli; Heavner, David

2012-02-01

68

Chance correlation in non-invasive glucose measurement using near-infrared spectroscopy  

International Nuclear Information System (INIS)

Although the non-invasive glucose measurement technique based on near-infrared (NIR) spectroscopy has been an active research area for over twenty years, a reliable monitoring method has not been established yet. The key problem is that the spectral variations due to glucose concentration are extremely small compared to that from other biological components. In addition, there are also some ambiguous time-dependent physiological processes, which make the explanation of the model more difficult, especially in the universal calibration. Therefore, in order to produce a model that is related to the actual spectral variation of glucose, reproducible measurements and clinical validation experiments that improve the selectivity and signal to noise ratio of glucose measurement are needed. In this paper, chance correlation in spectroscopy analysis is investigated, which is one of the obstacles to achieving successful NIR spectroscopy analysis, especially in in vivo measurement. The reasons for chance correlation in the in vitro and in vivo experiments are analysed. Methods to avoid it are suggested accordingly and verified with the in vitro experiments. We also investigate the chance correlation for the in vivo NIR diffuse reflectance spectroscopy monitoring blood. Results show that there is significant signal variation after glucose is taken, and the potential chance correlation factors including the instrument-related and physiology-related variations during the in vivo experiments do not contribute to the multivariate model for glucose concentration

69

Working Memory and Dynamic Measures of Analogical Reasoning as Predictors of Children's Math and Reading Achievement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Working memory and inductive reasoning ability each appear related to children’s achievement in math and reading. Dynamic measures of reasoning, based on an assessment procedure including feedback, may provide additional predictive value. The aim of this study was to investigate whether working memory and dynamic measures of analogical reasoning are unique predictors of children’s concurrent and subsequent reading and math achievement. School children (N= 188, M= 7.1 years, SD= 11months) ...

Stevenson, C. E.; Bergwerff, C. E.; Heiser, W. J.; Resing, W. C. M.

2013-01-01

70

Quantitative measurement of glucose utilization in dog brain using positron emission tomogram and 18FDG  

International Nuclear Information System (INIS)

Recent development of positron emission tomography and fluorine-18 labeled deoxy-glucose has enabled us to observe in vivo metabolism of glucose. For the application to human study, the method originally developed by Sokoloff et al. in rat brain was performed in dog brain using ECAT II in order to measure cerebral metabolic rate of glucose. Cross calibration between ECAT II and well counter was performed using phantom imaging and positron emmiter (Ga-68). Plasma 18-FDG was measured in well counter and calibrated. Cerebral metabolic rate of glucose (mg/100g brain.min) was calculated using ECAT images of 18-FDG and integrated activity of plasma 18-FDG from injection time (zero) to imaging time (t). 14.5mg/100g brain.min and 14.2mg/100g brain.min were obtained in frontal cortex and occipital cortex in anesthetized dog. (author)

71

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.

72

Selection circuits to evaluate analog signals in multi-channel measurement and control systems  

International Nuclear Information System (INIS)

The analog signals of neighbouring channels in multichannel measuring and central systems must be surveyed for impermissible deviations and used to generate representative signals. The principles of the selection circuits registering the generation and its behaviour in the case of defects or drop-out of the input signals are described. A realized circuit is presented which largely eliminates the effects of defects of input signals on representative signals. (orig.)

73

Photoacoustic measurement for glucose solution concentration based on tunable pulsed laser induced ultrasound  

Science.gov (United States)

Noninvasive measurement of blood glucose concentration (BGC) has become a research hotspot. BGC measurement based on photoacoustic spectroscopy (PAS) was employed to detect the photoacoustic (PA) signal of blood glucose due to the advantages of avoiding the disturbance of optical scattering. In this paper, a set of custom-built BGC measurement system based on tunable optical parametric oscillator (OPO) pulsed laser and ultrasonic transducer was established to test the PA response effect of the glucose solution. In the experiments, we successfully acquired the time resolved PA signals of distilled water and glucose aqueous solution, and the PA peak-to-peak values(PPV) were gotten under the condition of excitated pulsed laser with changed wavelength from 1340nm to 2200nm by increasing interval of 10nm, the optimal characteristic wavelengths of distilled water and glucose solution were determined. Finally, to get the concentration prediction error, we used the linear fitting of ordinary least square (OLS) algorithm to fit the PPV of 1510nm, and we got the predicted concentration error was about 0.69mmol/L via the fitted linear equation. So, this system and scheme have some values in the research of noninvasive BGC measurement.

Ren, Zhong; Liu, Guodong; Huang, Zhen; Zhao, Dengji

2012-12-01

74

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

75

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

76

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

77

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

International Nuclear Information System (INIS)

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

78

Evaluating the blood glucose measured via glucometry in diagnosis of hypoglycemia in neonates  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Hypoglycemia is one of the most prevalent problems seen in neonates and can lead toirreversible brain damage if not to be diagnosed in time. Today, the blood glucose is mostly checked bylaboratory methods that have a significant delay and can result in many adverse effects such as vesselrupture. The goal of this study was to evaluate the value of the glucometry device in diagnosis ofhypoglycemia in neonates.Materials and Methods: This study has been conducted over 156 hospitalized neonates in Amir almomenin Hospital, Semnan, Iran. The blood glucose in all cases has been simultaneously measured by bothlaboratory methods (glucose oxidase as the golden standard and glucometer. These measurements alongwith the relevant data for neonatal risk factors were recorded in the checklist. The blood glucosemeasurements of less than or equal 35 mg/dL in first two hours after birth, less than or equal 40mg/dL in 3to 24 hours after birth, less than or equal 45 mg/dL in more than 24 hours after birth are considered ashypoglycemic.Results: 58 neonates (37.2% were hypoglycemic.The measurement of blood glucose levels viaglucometer for hypoglycemia detection had a high precision (Area under curve = 0.941, Standard error=0.018, P= 0.0001. The optimum cut-off point yielded to equivalent of 51mg/dL. So that for fasting bloodglucose of less than or equal 51mg/dL, sensitivity, specificity, positive, and negative predictive values were,respectively, 94.7%, 81.6%, 75.3%, and 96.4%.Conclusion: Findings show that, blood glucose levels measured by glucometry have goodaccuracy for diagnosis of hypoglycemia in newborns. Thus, it is recommended that in case ofscreening and frequent need of monitoring neonatal blood glucose, this device be used as asuitable replacement of laboratory methods

Shamsollah Nooripoor

2012-06-01

79

The effect of borate polymer layers on glucose measurement by surface plasmon resonance  

Science.gov (United States)

A new borate polymer PAA-ran-PAAPBA that can adsorb glucose specifically is introduced into the glucose measurement based on surface plasmon resonance. Six and twelve layers of borate polymer are bound onto the SPR sensors respectively through the layer-by-layer self-assembly binding method, and then the effect of different layers on the glucose concentration measurement is studied. The experiment is conducted in three concentration ranges, 1~10mg/dL, 10~100mg/dL and 100~1000mg/dL. The Results show that the performance of 12-layer-polymer sensor is better than that of the 6-layer-polymer sensor in the first two ranges, and the measuring result has no big difference in the range of 100~1000mg/d. It indicates that the enhancement of polymer layer on the surface of SPR sensor can dramatically improve the glucose measurement in the low concentration range.

Li, Dachao; Yang, Jia; Wu, Peng; Yang, Di; Wang, Bo; Lin, Yuan; Xu, Kexin

2013-03-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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.

Hinkson, J.A. [Lawrence Berkeley Lab., CA (US); Unser, K.B. [Consultant, Genis-Pouilly (France)

1995-05-01

82

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

83

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

Science.gov (United States)

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.

Kleczek, R.; Grybos, P.; Szczygiel, R.

2014-06-01

84

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

85

Measurement of glucose concentration in turbid media by the polarization state of backscattered laser light  

Science.gov (United States)

Biological tissues, including human skin, are complex objects for optical measurements. Because of its multi-component structure, they are characterized by a combined response to various dynamic changes, both inside and outside of the biological object. Change of glucose concentration in the blood leads to a number of processes, which affect the light scattering properties of the skin and subcutaneous layers, herewith scattering coefficient and the polarization of the scattered light vary. The possibility of non-invasive blood glucose detection by parameters of backscattered laser light was experimentally demonstrated. Degree of polarization of light scattered by human skin and model objects was registered and dependence of the polarization state of backscattered radiation on the glucose concentration in the human blood was shown. A laboratory model of a differential polarimeter, which allows registering the parameters of the polarized radiation scattered by human skin and glucose containing models was developed. Using the developed model, model and full-scale experiments were conducted. In the model experiments, the light scattered in the forward and backwards direction by the following model objects: a 20% solution of milk and a 50% solution of whole human blood was investigated. The ability of the developed sensor to noninvasively detect the concentration of glucose in the blood was demonstrated.

Kafidova, Galina A.; Aksenov, Evgenii T.; Petrov, Victor M.

2013-06-01

86

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.

Rasouli R

2012-01-01

87

[Achievement of the noninvasive measurement for human blood glucose with NIR diffusion reflectance spectrum method].  

Science.gov (United States)

The noninvasive measurement of human blood glucose was achieved with NIR diffusion reflectance spectrum method. The thumb fingertip NIR diffusion reflectance spectra of six different age healthy volunteers were collected using Nexus-870 and its NIR fiber port smart accessory. The test was implemented with changing the blood glucose concentration for the limosis and satiation of every volunteer. The calibration model was set up using PLS method with the smoothing, baseline correction and first derivatives pretreatment spectrum in the 7500-8500 cm(-1) region for single volunteer, the same age combination and that of different age. When the spectrum was obtained, the actual blood glucose value of every spectrun sample was demarcated using ultraviolet spectrophotometer. The correlation between the calibration value and true value for single volunteer is better than that for the combination of volunteers, the correlative coefficients are all over 0.90471, RMSECs are all less than 0.171. PMID:16201363

Zhang, Hong-yan; Ding, Dong; Song, Li-qiang; Gu, Lin-na; Yang, Peng; Tang, Yu-guo

2005-06-01

88

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

89

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.

90

Investigation of 18F-2-deoxyglucose for the measure of myocardial glucose metabolism  

International Nuclear Information System (INIS)

18F labeled 2-deoxyglucose (18FDG) was studied as a glucose analog. Myocardial uptake and retention, blood clearance, species (dog, monkey, man) dependence and effect of diet on uptake were investigated. Normal myocardial uptake of 18FDG was 3 to 4% in dog and monkey and 1 to 4% of injected dose in man compared to brain uptake of 2% in dog, 5 to 6% in monkey and 4 to 8% in man. The metabolic rate (MR) for glucose in non-fasting (glycolytic state) was 2.8 times greater than in fasting (ketogenic state). Human subjects showed higher myocardial uptake after a normal meal than after meal containing mostly free fatty acids (FFA). Blood clearance was rapid with initial clearance t1/2 of 0.2 to 0.3 min followed by a t1/2 of 8.4 +- 1.2 min in dog and 11.6 +- 1.1 min in man. A small third component had a t1/2 of 59 +- 10 min and 88 +- 4 min in dog and man, respectively. High image contrast ratios between heart and blood (dog 3.5/1; man 14/1), heart and lung (dog 9/1; man 20/1), heart and liver (dog 15/1; man 10/1) were found with the ECAT positron tomograph. 18FDG was found to be rapidly taken up by the myocardium without any significant tissue clearance over a 4 hour period. 18FDG is transported, phosphorylated to 18FDG-6-PO4 and trapped in myocardial cells in the same manner as has been found for brain and exhibits excellent imaging properties. Determination of glucose and FFA MR in vivo with ECT provides a method for investigation and assessment of changing aerobic and anaerobic metabolic rates in ischemic heart disease in man

91

Double-injection FDG method to measure cerebral glucose metabolism twice in a single procedure  

International Nuclear Information System (INIS)

[18F]fluorodeoxyglucose (FDG) and positron emission tomography (PET) may be used to examine changes in cerebral glucose metabolism in two physiological conditions. We proposed and evaluated a double injection-single session FDG method with biological constraints for this purpose. Simulated brain time-radioactivity curves (TACs) generated by using a plasma TAC from an actual study and physiological combinations of input values in a kinetic model were analyzed to evaluate the accuracy of the proposed method. The reproducibility of the estimated values obtained by this method was tested in five normal volunteers who were studied with a dynamic PET scan and two injections of FDG in a single session while fasting. The simulation study showed that the estimated values obtained by the proposed method agreed well with the input values. In the human study, plasma glucose levels were 5.3±0.2 and 5.0±0.2 mM in the first and second measurements, respectively. The difference between the plasma glucose measurements was small but statistically significant (p*1 or rCMRglc, there were small deviations in K* (less than 10%) and LC (less than 5%) with a statistical significance (p* and LC seemed to relate to the difference in the plasma glucose level. The double-injection FDG method with biological constrains can be used to estimate rCMRglc and LC sequentially in a single PET scanning session. (author)

92

Study on the noninvasive blood glucose measurement by diffusion reflectance NIR spectroscopy  

Science.gov (United States)

The noninvasive measurement of human blood glucose has been a hotspot for a long time to all clinical workers over the world. In this paper the noninvasive measurement of human blood glucose with diffusion reflectance NIR spectrum method is presented. The thumb fingertip, the palm and the wrist with vein are chosen for the collection of diffusion reflectance NIR spectroscopy from six different age healthy volunteers using Nexus-870 and its NIR fiber port smart accessory. The calibration model is set up in 7500~8500cm-1 region that has the absorption of the glucose using Partial Least Squares (PLS) method with the first and second derivative spectral that had been smoothed and baseline corrected for single volunteer. The actual blood glucose value is determined by an ultraviolet spectrophotometer. The model with the spectrum obtained at the wrist is better than from other part for all volunteers, and it is much steadier with the second derivative pretreatment spectral than with the first derivative ones. The correlative coefficients are all over 0.93772; RMSECs are all less than 0.310 and the max differences are between -0.6mmo/L and +0.8mmo/L with the second derivative method. Some samples are kept for prediction with their own model. The differences are under 0.875529mmol/L.

Zhang, Hongyan; Song, Liqiang; Wang, Hongyan; Wang, Cheng; Tang, Yuguo

2005-01-01

93

Advancement in polarimetric glucose sensing: simulation and measurement of birefringence properties of cornea  

Science.gov (United States)

Clinical guidelines dictate that frequent blood glucose monitoring in diabetic patients is critical towards proper management of the disease. Although, several different types of glucose monitors are now commercially available, most of these devices are invasive, thereby adversely affecting patient compliance. To this end, optical polarimetric glucose sensing through the eye has been proposed as a potential noninvasive means to aid in the control of diabetes. Arguably, the most critical and limiting factor towards successful application of such a technique is the time varying corneal birefringence due to eye motion artifact. We present a spatially variant uniaxial eye model to serve as a tool towards better understanding of the cornea's birefringence properties. The simulations show that index-unmatched coupling of light is spatially limited to a smaller range when compared to the index-matched situation. Polarimetric measurements on rabbits' eyes indicate relative agreement between the modeled and experimental values of corneal birefringence. In addition, the observed rotation in the plane of polarized light for multiple wavelengths demonstrates the potential for using a dual-wavelength polarimetric approach to overcome the noise due to timevarying corneal birefringence. These results will ultimately aid us in the development of an appropriate eye coupling mechanism for in vivo polarimetric glucose measurements.

Malik, Bilal H.; Coté, Gerard L.

2011-03-01

94

Detecting analogies unconsciously.  

Science.gov (United States)

Analogies may arise from the conscious detection of similarities between a present and a past situation. In this functional magnetic resonance imaging study, we tested whether young volunteers would detect analogies unconsciously between a current supraliminal (visible) and a past subliminal (invisible) situation. The subliminal encoding of the past situation precludes awareness of analogy detection in the current situation. First, participants encoded subliminal pairs of unrelated words in either one or nine encoding trials. Later, they judged the semantic fit of supraliminally presented new words that either retained a previously encoded semantic relation ("analog") or not ("broken analog"). Words in analogs versus broken analogs were judged closer semantically, which indicates unconscious analogy detection. Hippocampal activity associated with subliminal encoding correlated with the behavioral measure of unconscious analogy detection. Analogs versus broken analogs were processed with reduced prefrontal but enhanced medial temporal activity. We conclude that analogous episodes can be detected even unconsciously drawing on the episodic memory network. PMID:24478656

Reber, Thomas P; Luechinger, Roger; Boesiger, Peter; Henke, Katharina

2014-01-01

95

Detecting analogies unconsciously  

Directory of Open Access Journals (Sweden)

Full Text Available Analogies may arise from the conscious detection of similarities between a present and a past situation. In this functional magnetic resonance imaging study, we tested whether young volunteers would detect analogies unconsciously between a current supraliminal (visible and a past subliminal (invisible situation. The subliminal encoding of the past situation precludes awareness of analogy detection in the current situation. First, participants encoded subliminal pairs of unrelated words in either one or nine encoding trials. Later, they judged the semantic fit of supraliminally presented new words that either retained a previously encoded semantic relation (‘analog’ or not (‘broken analog’. Words in analogs versus broken analogs were judged closer semantically, which reflects unconscious analogy detection. Hippocampal activity associated with subliminal encoding correlated with the behavioral measure of unconscious analogy detection. Analogs versus broken analogs were processed with reduced prefrontal but enhanced medial temporal activity. We conclude that analogous episodes can be detected even unconsciously drawing on the episodic memory network.

KatharinaHenke

2014-01-01

96

Statins impair glucose uptake in human cells  

Science.gov (United States)

Objective Considering the increasing number of clinical observations indicating hyperglycemic effects of statins, this study was designed to measure the influence of statins on the uptake of glucose analogs by human cells derived from liver, adipose tissue, and skeletal muscle. Design Flow cytometry and scintillation counting were used to measure the uptake of fluorescently labeled or tritiated glucose analogs by differentiated visceral preadipocytes, skeletal muscle cells, skeletal muscle myoblasts, and contact-inhibited human hepatocellular carcinoma cells. A bioinformatics approach was used to predict the structure of human glucose transporter 1 (GLUT1) and to identify the presence of putative cholesterol-binding (cholesterol recognition/interaction amino acid consensus (CRAC)) motifs within this transporter. Mutagenesis of CRAC motifs in SLC2A1 gene and limited proteolysis of membrane GLUT1 were used to determine the molecular effects of statins. Results Statins significantly inhibit the uptake of glucose analogs in all cell types. Similar effects are induced by methyl-?-cyclodextrin, which removes membrane cholesterol. Statin effects can be rescued by addition of mevalonic acid, or supplementation with exogenous cholesterol. Limited proteolysis of GLUT1 and mutagenesis of CRAC motifs revealed that statins induce conformational changes in GLUTs. Conclusions Statins impair glucose uptake by cells involved in regulation of glucose homeostasis by inducing cholesterol-dependent conformational changes in GLUTs. This molecular mechanism might explain hyperglycemic effects of statins observed in clinical trials.

Nowis, Dominika; Malenda, Agata; Furs, Karolina; Oleszczak, Bozenna; Sadowski, Radoslaw; Chlebowska, Justyna; Firczuk, Malgorzata; Bujnicki, Janusz M; Staruch, Adam D; Zagozdzon, Radoslaw; Glodkowska-Mrowka, Eliza; Szablewski, Leszek; Golab, Jakub

2014-01-01

97

Quantitative comparison of measurements of cerebral glucose metabolic rate made with two positron cameras  

International Nuclear Information System (INIS)

The rapid progress in PET technology has created the dilemma of how to compare data from old and new tomographs. We examined cerebral metabolic data from two scanners, with different spatial resolutions and methods of attenuation correction, to see if metabolic values from the lower-resolution tomograph (ECAT II) could be adjusted to make them comparable to data from the higher-resolution scanner (Scanditronix PC1024-7B). Nine subjects were scanned on both tomographs after a single injection of [18F]2-fluoro-2-deoxy-D-glucose. Regional and lobar gray matter metabolic rates for glucose were obtained from comparable images from each scanner. Ratios of lobar to global gray matter metabolism also were calculated. Regression coefficients and percent differences were computed to compare ECAT II and PC1024 data. Two-thirds of the region pairs showed significant regressions, although percent differences were quite variable, with measures of glucose utilization ranging from 30 to 120% higher on the PC1024 compared to those from the ECAT II. Comparisons of lobar glucose rates between the two machines were less variable (50 to 80%), and ratios differed by only +/- 5% (except for the temporal ratios). Since there was no simple and consistent relationship between regional metabolic rates on the two tomographs, an overall adjustment of regional ECAT values for comparison to PC1024 values would be impossible. A region-by-region adjustment would be necessary. Lobar ratios are sufficiently similar that direct comparisons might be possible

98

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

Science.gov (United States)

In order to overcome the existing shortcomings of the non-invasive blood glucose polarized light measurement methods of optical heterodyne detection and direct detection, we present in this paper a new orthogonal twin-polarized light (OTPL) non-invasive blood glucose measurement method, which converts the micro-angle rotated by an optical active substance such as glucose to the energy difference of OTPL, amplifies the signals by the high-sensitivity lock-in amplifier made of relevant principle, controls Faraday coil current to compensate the changes in deflection angle caused by blood glucose, and makes use of the linear relationship between blood glucose concentration and Faraday coil current to calculate blood glucose concentration. In our comparative experiment using the data measured by LX-20 automatic biochemical analyzer as a standard, a 0.9777 correlation coefficient is obtained in glucose concentration experiment, and a 0.952 in serum experiment. The result shows that this method has higher detection sensitivity and accuracy and lays a foundation for the development of practical new type of non-invasive blood glucose tester for diabetic patients. PMID:20481302

Wang, Hong; Wu, Baoming; Liu, Ding

2010-04-01

99

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

100

d-Glucose Transport System of Zymomonas mobilis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The properties of the d-glucose transport system of Zymomonas mobilis were determined by measuring the uptake of nonmetabolizable analogs (2-deoxy-d-glucose and d-xylose) by wild-type cells and the uptake of d-glucose itself by a mutant lacking glucokinase. d-Glucose was transported by a constitutive, stereospecific, carrier-mediated facilitated diffusion system, whereby its intracellular concentration quickly reached a plateau close to but not above the external concentration. d-Xylose was t...

Dimarco, Anthony A.; Romano, Antonio H.

1985-01-01

 
 
 
 
101

Working Memory and Dynamic Measures of Analogical Reasoning as Predictors of Children's Math and Reading Achievement  

Science.gov (United States)

Working memory and inductive reasoning ability each appear related to children's achievement in math and reading. Dynamic measures of reasoning, based on an assessment procedure including feedback, may provide additional predictive value. The aim of this study was to investigate whether working memory and dynamic measures of analogical

Stevenson, Claire E.; Bergwerff, Catharina E.; Heiser, Willem J.; Resing, Wilma C. M.

2014-01-01

102

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.

103

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

104

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

105

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

106

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

107

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

108

Measurement of temporal asymmetries of glucose consumption using linear profiles: reproducibility and comparison with visual analysis  

International Nuclear Information System (INIS)

The aim of our study was to test the reproducibility of this method and to compare its diagnostic performance to that of visual analysis in patients with complex partial seizures (CPS). Regional cerebral glucose consumption (rCMRGLc) was measured interictally in 25 CPS patients and 10 controls using F-18-deoxyglucose and the positron emission tomography (PET) camera ECAT EXACT 47. The PET scans were visually analyzed for the occurrence of unilateral temporal hypometabolism. Furthermore, rCMRGLc was quantified on six contiguous coronal planes by manually tracing maximal values of temporal glucose consumption, thus creating line profiles of temporal glucose consumption for each side. Indices of asymmetry (ASY) were then calculated from these line profiles in four temporal regions and compared to the corresponding 95% confidence intervals of the control data. All analyses were performed by two observers independently from each other and without knowledge of the clinical findings. The agreement between the two observers with regard to focus lateralization was 96% on visual analysis and 100% on quantitative analysis. There was an excellent agreement with regard to focus lateralization between visual and quantitative evaluation. (orig.)

109

Method for measurement of glucose enrichment in serum using isotope dilution mass spectrometry and its application for measurement of glucose kinetics  

International Nuclear Information System (INIS)

An isotope dilution mass spectrometric method has been developed for kinetic studies of D-glucose in humans, using 6,6-dideuteroglucose as the internal standard. Glucose in plasma samples was purified by anion and cation exchange column chromatography after deproteinization and derivatized to ?-D-glucofuranose cyclic 1,2:3,5-bis (butylboronate)-6-acetate

110

Photoacoustic depth profiling of a skin model for non-invasive glucose measurement.  

Science.gov (United States)

A measurable depth of the blood glucose level by using photoacoustic spectroscopy (PAS) was discussed experimentally in order to improve detection sensitivity. Since a measurable depth of the PAS depends on a modulation frequency of the chopped light irradiated to a sample, the relationship between modulation frequency and the thickness of a sample was evaluated. The photoacoustic detector used in these experiments consisted of an acoustic resonance pipe and an optical microphone, and a two-layer model composed of silicone sheets with the different optical absorption. The measurable depth was 2-3 mm with modulation frequency of 1000-2000 Hz. Furthermore, the reason for the measurable depth to be deeper than the thermal diffusion length of the sample was discussed theoretically. From these analyses of thermoelastic wave, the relation between the photoacoustic signal propagation and the measurable depth in a tissue was clarified. PMID:19163997

Wadamori, Naoki; Shinohara, Ryou; Ishihara, Yasutoshi

2008-01-01

111

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

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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

112

Measurement of glucose metabolism in rat spinal cord slices with dynamic positron autoradiography  

International Nuclear Information System (INIS)

We attempted to measure the regional metabolic rate of glucose (MRglc) in sliced spinal cords in vitro. The thoracic spinal cord of a mature Wister rat was cut into 400-?m slices in oxygenated and cooled (1-4 deg. C) Krebs-Ringer solution. After at least 60 min of preincubation, the spinal cord slices were transferred into double polystyrene chambers and incubated in Krebs-Ringer solution at 36 deg. C, bubbled with 5% O2/5% CO2 gas. To measure MRglc, we used the dynamic positron autoradiography technique (dPAT) with F-18-2-fluoro-2-deoxy-D-glucose ([18F]FDG) and the net influx constant of [18F]FDG as an index. Uptake curves of [18F]FDG were well fitted by straight lines for more than 7 h after the slicing of the spinal cord (linear regression coefficient, r=0.99), indicating a constant uptake of glucose by the spinal cord tissue. The slope (K), which denotes MRglc, is affected by tetrodotoxin, and high K+ (50 mM) or Ca2+-free, high Mg2+ solution. After 10 min of hypoxia, the K value following reoxygenation was similar to the unloaded control value, but after 45 min of hypoxia, the K value was markedly lower than the unloaded control value, and after >90 min of reoxygenation it was nearly 0. Our results indicate that the living spinal cord slices used retained an activity-dependent metabolism to some extent. This technique may provide a new approach for measuring MRglc in sliced living spinal cord tissue in vitro and for quantifying the dynamic changes in MRglc in response to various interventions such as hypoxia

113

Measurement of glucose metabolism in rat spinal cord slices with dynamic positron autoradiography  

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We attempted to measure the regional metabolic rate of glucose (MRglc) in sliced spinal cords in vitro. The thoracic spinal cord of a mature Wister rat was cut into 400-{mu}m slices in oxygenated and cooled (1-4 deg. C) Krebs-Ringer solution. After at least 60 min of preincubation, the spinal cord slices were transferred into double polystyrene chambers and incubated in Krebs-Ringer solution at 36 deg. C, bubbled with 5% O{sub 2}/5% CO{sub 2} gas. To measure MRglc, we used the dynamic positron autoradiography technique (dPAT) with F-18-2-fluoro-2-deoxy-D-glucose ([{sup 18}F]FDG) and the net influx constant of [{sup 18}F]FDG as an index. Uptake curves of [{sup 18}F]FDG were well fitted by straight lines for more than 7 h after the slicing of the spinal cord (linear regression coefficient, r=0.99), indicating a constant uptake of glucose by the spinal cord tissue. The slope (K), which denotes MRglc, is affected by tetrodotoxin, and high K{sup +} (50 mM) or Ca{sup 2+}-free, high Mg{sup 2+} solution. After 10 min of hypoxia, the K value following reoxygenation was similar to the unloaded control value, but after 45 min of hypoxia, the K value was markedly lower than the unloaded control value, and after >90 min of reoxygenation it was nearly 0. Our results indicate that the living spinal cord slices used retained an activity-dependent metabolism to some extent. This technique may provide a new approach for measuring MRglc in sliced living spinal cord tissue in vitro and for quantifying the dynamic changes in MRglc in response to various interventions such as hypoxia.

Fan Xiaoping [Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People' s Hospital, Guangzhou 510100 (China); Asai, Tatsuya [Biomedical Imaging Research Center, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Morioka, Koichi [Department of Cardiovascular Surgery II, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Uchida, Kenzo; Baba, Hisatoshi [Department of Orthopaedics and Rehabilitation Medicine, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Tanaka, Kuniyoshi [Department of Cardiovascular Surgery II, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Zhuang Jian [Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People' s Hospital, Guangzhou 510100 (China); Okazawa, Hidehiko [Biomedical Imaging Research Center, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Fujibayashi, Yasuhisa [Biomedical Imaging Research Center, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan)], E-mail: yfuji@u-fukui.ac.jp

2009-02-15

114

The synthesis of 1-[11C]-D-glucose and related compounds for the measurement of brain glucose metabolism  

International Nuclear Information System (INIS)

A new synthesis of 1-:11C:-D-glucose (3) and related compounds from H11CN is described. Reaction of D-arabinose (1) with Na11CN at pH 8 gives 1-:11C:-aldononitriles (2). Reduction of 2 with Raney alloy in 30% formic acid gives 1-[11C]-D-glucose (3) and 1-[11C]-D-mannose (4) in radiochemical yields of approx. 40-50% (EOB) in a synthesis time of 50 min from EOB. The yield and ratio of 3 and 4 is pH dependent. Compounds 3 and 4 are separated by HPLC. The radiochemical yield of 3 is approx. 15% (EOB) and the total synthesis time (including HPLC purification) is 70 min from EOB. The same method has also been applied to synthesize 1-:11C:-D-galactose (6) with radiochemical yields of approx. 30% (EOB) in a synthesis time of 70 min from EOB. The advantages and disadvantages of this synthetic method are discussed. (author)

115

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

116

MTV Measurements of the Velocity Field During the Uni-Directional Solidification of an Alloy Analog  

Science.gov (United States)

The use of uni-directional solidification for alloys can provide increased resistance to creep and thermal fatigue in the final solidified ingot. However, solutal and thermal forces can produce imperfections in the form of solute-rich channels during the solidification of a binary alloy under off-eutectic conditions. In this work, the technique of Molecular Tagging Velocimetry (MTV) is used to investigate the transient velocity field present during the uni-directional solidification of a transparent alloy analog (ammonium chloride). Whole-field two-component velocity maps near the mushy layer and above the chimney are measured at different times during the solidification process and at different locations. Results in the region above the mushy zone show well-defined convective flow patterns within the bulk fluid with peak velocities on the order of 1 mm/s for both velocity components at the early stages of the solidification process. The plumes are found to have a maximum velocity of order 7 mm/s in the upward component. The capabilities and limitations of the MTV method in this application are discussed.

Lum, Chee; Benard, Andre; Diaz, Alejandro; Koochesfahani, Manoochehr; McGrath, John

2001-11-01

117

Laboratory measurements of p-wave seismic Q on lunar and analog rocks  

Science.gov (United States)

The longitudinal-wave, internal friction quality factor (Qp) of out-gassed rock subjected to hydrostatic confining pressure was measured by a technique of aerodynamically shaping the sample ends to remove most of the air drag. Q values of about 1000 and 100 were obtained at 100 MPa and in laboratory air, respectively. The temperature dependence of Q in lunar rock 70215.85 and an analog of lunar basalt was investigated over the range -100 to 450 deg C. A systematic increase in Q was observed at 50 Hz, 5 kHz and 50 kHz. When the temperature was lowered to -100 deg C moderate decreases in Q were observed from 100 to 250 deg C, and high Q values were obtained at 450 deg C. The temperature and pressure dependences of Q suggest that high lunar seismic Q values imply a very dry crust to depths of at least 50 km. These results further indicate that elastic waves are damped in volatile-rich rock by an absorption mechanism which involves changes in the bonding, structure and coverage of the molecular, physisorbed and chemisorbed H2O at crack and grain boundaries.

Tittmann, B. R.; Nadler, H.; Richardson, J. M.; Ahlberg, L.

1978-01-01

118

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

119

Comparison between free serum thyroxine levels, measured by analog and dialysis methods, in the presence of perfluorooctane sulfonate and perfluorooctanoate.  

Science.gov (United States)

Results from animal studies have shown that negative associations between serum levels of free thyroxine (FT4) and perfluorooctane sulfonate (PFOS) at concentrations much higher than those reported for any exposed population may be due to bias in analog methods used for measuring FT4. We aimed to assess if there is evidence of differences between human FT4 measurements in serum by an analog and a dialysis method due to the presence of PFOS or perfluorooctanoate (PFOA) in a population of 50 adults with typical US serum PFOS concentrations but higher PFOA concentrations. Mean analog-dialysis difference was -0.02 (95% CI=-0.06, 0.02). Regressing the difference between FT4 measurements on either PFOA or PFOS serum concentrations yielded slopes close to zero. The present findings do not indicate any observable bias from the use of the analog with respect to the dialysis method, across the range of PFOS and PFOA concentrations in this population. PMID:21530636

Lopez-Espinosa, Maria-Jose; Fitz-Simon, Nicola; Bloom, Michael S; Calafat, Antonia M; Fletcher, Tony

2012-07-01

120

Interaction of fructose with the glucose permease of the cyanobacterium Synechocystis sp. strain PCC 6803.  

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Fructose was bactericidal for the cyanobacterium Synechocystis sp. strain PCC 6803. Each of ten independently isolated fructose-resistant mutants had an alteration of the glucose transport system, measured as uptake of glucose or of 3-O-methyl-D-glucose. In the presence of the analog, the wild-type Synechocystis strain was protected against fructose. Two mutants altered in photoautotrophy were also isolated.

Flores, E.; Schmetterer, G.

1986-01-01

 
 
 
 
121

Correlation Between Analog Noise Measurements and the Expected Bit Error Rate of a Digital Signal Propagating Through Passive Components  

Science.gov (United States)

A method of determining the bit error rate (BER) of a digital circuit from the measurement of the analog S-parameters of the circuit has been developed. The method is based on the measurement of the noise and the standard deviation of the noise in the S-parameters. Once the standard deviation and the mean of the S-parameters are known, the BER of the circuit can be calculated using the normal Gaussian function.

Warner, Joseph D.; Theofylaktos, Onoufrios

2012-01-01

122

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

123

Design and performance of a multichannel multisampling analog to digital converter board for energy measurement  

International Nuclear Information System (INIS)

This paper describes a VME multichannel multisampling ADC board designed for low-energy physics experiments. To guarantee the maximum experimental flexibility the module is completely programmable through a digital signal processor and a program register accessible via VME bus. With a frequency of 40 MHz, the single channel can acquire a variable number of samples of each analog input. Besides, it is possible to use the board as a 160 MHz waveform digitizer, grouping four channels together and feeding the same analog inputs via an external fan-out

124

Fast collimated neutron flux measurement using stilbene scintillator and flashy analog-to-digital converter in JT-60U  

International Nuclear Information System (INIS)

A line-integrated neutron emission profile is routinely measured using the radial neutron collimator system in JT-60U tokamak. Stilbene neuron detectors (SNDs), which combine a stilbene organic crystal scintillation detector (SD) with an analog neutron-gamma pulse shape discrimination (PSD) circuit, have been used to measure collimated neutron flux. Although the SND has many advantages as a neutron detector, the maximum count rate is limited up to ?1x105 counts/s due to the analog PSD circuit. To overcome this issue, a digital signal processing system (DSPS) using a flash analog-to-digital converter (Acqiris DC252, 8 GHz, 10 bits) has been developed at Cyclotron and Radioisotope Center in Tohoku University. In this system anode signals from photomultiplier of the SD are directory stored and digitized. Then, the PSD between neutrons and gamma rays is performed using software. The DSPS has been installed in the vertical neutron collimator system in JT-60U and applied to deuterium experiments. It is confirmed that the PSD is sufficiently performed and collimated neutron flux is successfully measured with count rate up to ?5x105 counts/s without the effect of pileup of detected pulses. The performance of the DSPS as a neutron detector, which supersedes the SND, is demonstrated

125

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

126

Measurement of glucose turnover and oxidation using radioactive and stable isotopes  

International Nuclear Information System (INIS)

Isotopes have become the best means for investigating glucose kinetics in vivo. With the recent greater availability of stable isotopes there has developed a need to understand how data may be obtained from the use of both radioactive and stable glucose tracers. Described for the nonexpert is the calculation of glucose appearance and disappearance, clearance and oxidation using both stable and radioactive glucose isotopes, administered both by bolus and primed constant infusion and under both steady and nonsteady state conditions. Other substrates may be studied using similar methodology. The use of stable substrate isotopes will be an expanding field of metabolic research in man

127

The measurement of glucose turnover and oxidation using radioactive and stable isotopes  

International Nuclear Information System (INIS)

Isotopes have become the best means for investigating glucose kinetics in vivo. With the recent greater availability of stable isotopes there has developed a need to understand how data may be obtained from the use of both radioactive and stable glucose tracers. Described for the nonexpert is the calculation of glucose appearance and disappearance, clearance and oxidation using both stable and radioactive glucose isotopes, administered both by bolus and primed constant infusion and under both steady and nonsteady state conditions. Other substrates may be studied using similar methodology. The use of stable substrate isotopes will be an expanding field of metabolic research in man

128

Nucleic Acid Base Analog FRET-Pair Facilitating Detailed Structural Measurements in Nucleic Acid Containing Systems  

DEFF Research Database (Denmark)

We present the first nucleobase analog fluorescence resonance energy transfer (FRET)-pair. The pair consists of tCO, 1,3-diaza-2-oxophenoxazine, as an energy donor and the newly developed tC(nitro), 7-nitro-1,3-diaza-2-oxophenothiazine, as an energy acceptor. The FRET-pair successfully monitors distances covering up to more than one turn of the DNA duplex. Importantly, we show that the rigid stacking of the two base analogs, and consequently excellent control of their exact positions and orientations, results in a high control of the orientation factor and hence very distinct FRET changes as the number of bases separating tCO and tC(nitro) is varied. A set of DNA strands containing the FRET-pair at wisely chosen locations will, thus, make it possible to accurately distinguish distance- from orientation-changes using FRET. In combination with the good nucleobase analog properties, this points toward detailed studies of the inherent dynamics of nucleic acid structures. Moreover, the placement of FRET-pair chromophores inside the base stack will be a great advantage in studies where other (biomacro)molecules interact with the nucleic acid. Lastly, our study gives possibly the first truly solid experimental support to the dependence of energy transfer efficiency on orientation of involved transition dipoles as predicted by the Forster theory.

Börjesson, Karl; Preus, SØren

2009-01-01

129

Inhibition of JNK Phosphorylation by a Novel Curcumin Analog Prevents High Glucose-Induced Inflammation and Apoptosis in Cardiomyocytes and the Development of Diabetic Cardiomyopathy.  

Science.gov (United States)

Hyperglycemia-induced inflammation and apoptosis have important roles in the pathogenesis of diabetic cardiomyopathy. We recently found that a novel curcumin derivative, C66, is able to reduce the high glucose (HG)-induced inflammatory response. This study was designed to investigate the protective effects on diabetic cardiomyopathy and its underlying mechanisms. Pretreatment with C66 significantly reduced HG-induced overexpression of inflammatory cytokines via inactivation of nuclear factor-?B in both H9c2 cells and neonatal cardiomyocytes. Furthermore, we showed that the inhibition of Jun NH2-terminal kinase (JNK) phosphorylation contributed to the protection of C66 from inflammation and cell apoptosis, which was validated by the use of SP600125 and dominant-negative JNK. The molecular docking and kinase activity assay confirmed direct binding of C66 to and inhibition of JNK. In mice with type 1 diabetes, the administration of C66 or SP600125 at 5 mg/kg significantly decreased the levels of plasma and cardiac tumor necrosis factor-?, accompanied by decreasing cardiac apoptosis, and, finally, improved histological abnormalities, fibrosis, and cardiac dysfunction without affecting hyperglycemia. Thus, this work demonstrated the therapeutic potential of the JNK-targeting compound C66 for the treatment of diabetic cardiomyopathy. Importantly, we indicated a critical role of JNK in diabetic heart injury, and suggested that JNK inhibition may be a feasible strategy for treating diabetic cardiomyopathy. PMID:24848068

Pan, Yong; Wang, Yi; Zhao, Yunjie; Peng, Kesong; Li, Weixin; Wang, Yonggang; Zhang, Jingjing; Zhou, Shanshan; Liu, Quan; Li, Xiaokun; Cai, Lu; Liang, Guang

2014-10-01

130

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.)

131

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

132

Radical carbocyclization reactions of ortho-iodoallyloxybenzoate derivatives of d-glucose and d-galactose and comparison with the reactions of their benzamide analogs  

International Nuclear Information System (INIS)

Two orthoiodoallyloxybenzoates, methyl 4-O-allyl-2,3-di-O-benzyl-6-O-(2-iodobenzoyl)-?-D-glucopyranoside (3) and methyl 4-O-allyl-2,3-di-O-benzyl-6-O-(2-iodobenzoyl)-?-D-galactopyranoside (4) were synthesized in seven conventional steps from methyl ?-D glucopyranoside and methyl ?-D-galactopyranoside, respectively. Bu3SnH-mediated aryl radical cyclization of 3 provided exclusively the hydrogenolysis product 12. The reaction of 4 gave the reduced uncyclized product 13 and only traces of 4A, resulting from 11-endo aryl radical cyclization. In previous papers we described that in similar Bu3SnH-mediated radical reaction of orthoiodoallyloxybenzamides, analogs of 3 and 4, we obtained macrolactams resulting from 11-endo cyclization. An hypothesis to explain the differences is presented. It was assumed that in the aryl radical formed from iodobenzamides there is a suitable conformation to cyclization, which is stabilized by an intramolecular hydrogen bond. (author)

133

Measuring preoperative anxiety in patients with breast cancer using the visual analog scale.  

Science.gov (United States)

Preoperative anxiety is a prevalent concern with deleterious effects in patient recovery and is not routinely assessed in the preoperative screening process. When it is assessed, it may prompt an increase in the use of anesthetic agents, heightened postoperative pain, and prolonged hospitalization. Preoperative women with breast cancer face anxiety as it relates to anesthesia, surgery, and recovery. The preoperative anxiety visual analog scale may identify and quantify anxiety in this population, provide advocacy and support, and improve the preoperative screening process. PMID:25253102

Aviado-Langer, Jennifer

2014-10-01

134

31P-NMR-spectroscopy measurements of energy metabolism of in vivo growing ascites tumours following addition of glucose  

International Nuclear Information System (INIS)

The cellular ATP content and the phosphorylation potential, defined as the ATP, ADP and inorganic phosphate (Pi) ratios, of exponentially growing Ehrlich ascites tumour cells were compared with cells at the plateau phase of growth. These phosphorus compounds were measured using 31P-NMR-spectroscopy immediately after removal of the cell material from the host and in their ascites fluid reflecting in vivo growth conditions. Reaching the plateau phase of growth, the ATP content and the phosphorylation potential decreased. Upon addition of glucose, the phosphorylation potential immediately increased. We concluded that the reduced phosphorylation potential was due to a limited availability of glucose in spite of the nearly normal blood glucose concentration found. An increasing diffusion distance from the host to all parts of the tumour is a possible reason for that. (orig.)

135

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?

Rasmussen, L Melholt; Steenstrup, T

2012-01-01

136

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

2014-01-01

137

Fluorescence spectroscopic study on complexation of uranium(VI) by glucose: a comparison of room and low temperature measurements  

International Nuclear Information System (INIS)

Cryogenic techniques are currently used in scanning tunnelling microscopy (STM) and single molecule spectroscopy. Recently such cryogenic devices have also been adapted to time resolved laser-induced fluorescence spectroscopy (TRLFS) systems applied to uranium(VI). In our study, we interpret TRLFS results obtained for the uranyl(VI) glucose system at room temperature (RT) and under cryogenic conditions of 153 K (cryo-TRLFS). A uranyl(VI) glucose complex was only identified by cryo-TRLFS measurements at pH 5 and not by RT measurements. The uranyl(VI) glucose complex was characterized by five emission bands at 499.0, 512.1, 525.2, 541.7, and 559.3 nm and a fluorescence lifetime of 20.9 ± 2.9 ?s. The uranyl(VI) glucose complex formation constant was calculated for the first time to be log?I=0.1M 15.25 ± 0.96. Cryo-TRLFS investigation opens up new possibilities for the determination of complex formation constants since interfering quenching effects often encounter at RT are suppressed by measurements at cryogenic conditions. (author)

138

Age and sex differences in cerebral glucose consumption measured by pet using [18-F] fluorodeoxyglucose (FDG)  

International Nuclear Information System (INIS)

Resting cerebral glucose metabolic rates (CMRglc) were measured in 23 subjects by PET using FDG. Subjects were divided into several groups (mean age +- S.D.) 5 young males (YM) (27 +- 6); 6 young females (YF)(33 +9); 5 elderly males (EM)(73 +- 5); 7 elderly females (EF)(69 +- 7). Additionally, from these groups 4 YM, 3YF, 5EM and 4EF were studied again within 6 weeks under identical conditions. CMRglc in the YF group again was significantly hider than YM (p 0.05). No obvious relationships of CMRglc to the phase of the menstrual cycle was found in this small group. There was a trend (p=0.06) toward a higher CMRglc in YF than EF. These results support the findings of higher CBF in YF versus YM. The differences between the results of Kuhl et al (J. Cereb. and a reduction of CMRglc with age was found in a mixed group of males and females (58and female), and where no age effect was found the males, are also resolved by these findings. The authors suggest that the apparent age effect, in females in this study, is principally a hormonal one

139

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

140

Analysis of FTO Gene Variants with Measures of Obesity and Glucose Homeostasis in the IRAS Family Study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Multiple studies have identified FTO gene variants associated with measures of adiposity in European-derived populations. The study objective was to determine whether FTO variants were associated with adiposity, including visceral and subcutaneous adipose tissue (VAT; SAT), and glucose homeostasis measures in the Insulin Resistance Atherosclerosis Family Study (IRASFS). A total of 27 SNPs in FTO intron 1, including SNPs prominent in the literature (rs9939609, rs8050136, rs1121980, rs17817449,...

Wing, Maria R.; Ziegler, Julie; Langefeld, Carl D.; Ng, Maggie Cy; Haffner, Steven M.; Norris, Jill M.; Goodarzi, Mark O.; Bowden, Donald W.

2009-01-01

 
 
 
 
141

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

International Nuclear Information System (INIS)

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 28 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

142

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

143

Effects of Zinc Supplementation on the Anthropometric Measurements, Lipid Profiles and Fasting Blood Glucose in the Healthy Obese Adults  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of this study was to assess the effects of zinc supplementation on anthropometric measures, improving lipid profile biomarkers, and fasting blood glucose level in obese people. Methods: This randomized, double- blind clinical trial was carried out on 60 obese participants in the 18-45 age range for one month. The participants were randomly divided into the intervention group, who received 30 mg/d zinc gluconate, and the placebo group who received 30mg/d starch. Anthropometric measurements (body mass index (BMI, weight and waist circumference were recorded before and at the end of study. Lipid profile biomarkers and fasting blood glucose were determined using enzymatic procedure. Analysis of Covariance (ANCOVA test was run to compare the post-treatment values of the two groups, and t-test was conducted to compare within group changes. Results: Serum zinc concentration was increased significantly in intervention group (p=0.024. BMI and body weight was significantly decreased (p=0.030 and p=0.020, respectively. Lipid profile biomarkers and fating blood glucose did not change significantly but triglyceride level was significantly decreased (p=0.006 in the intervention group. Conclusion: The obtained results indicate that zinc supplementation improves BMI, body weight, and triglyceride concentration without considerable effects on lipid profile and glucose level. Zinc can be suggested as a suitable supplementation therapy for obese people, but more studies are needed to verify the results.

Sepide Mahluji

2013-02-01

144

Extracellular glucose concentrations in the rat hippocampus measured by zero-net-flux: effects of microdialysis flow rate, strain, and age.  

Science.gov (United States)

The concentration of glucose in the brain's extracellular fluid remains controversial, with recent estimates and measurements ranging from 0.35 to 3.3 mM. In the present experiments, we used the method of zeronet-flux microdialysis to determine glucose concentration in the hippocampal extracellular fluid of awake, freely moving rats. In addition, the point of zero-net-flux was measured across variations in flow rate to confirm that the results for glucose measurement were robust to such variations. In 3-month-old male Sprague-Dawley rats, the concentration of glucose in the hippocampal extracellular fluid was found to be 1.00 +/- 0.05 mM, which did not vary with changes in flow rate. Three-month-old and 24-month-old Fischer-344 rats both showed a significantly higher hippocampal extracellular fluid glucose concentration, at 1.24 +/- 0.07 and 1.21 +/- 0.04 mM, respectively; there was no significant difference between the two age groups. The present data demonstrate variation in extracellular brain glucose concentration between rat strains. When taken together with previous data showing a striatal extracellular glucose concentration on the order of 0.5 mM, the data also demonstrate variation in extracellular glucose between brain regions. Traditional models of brain glucose transport and distribution, in which extracellular concentration is assumed to be constant, may require revision. PMID:9930754

McNay, E C; Gold, P E

1999-02-01

145

51 OPHIUCHUS: A POSSIBLE BETA PICTORIS ANALOG MEASURED WITH THE KECK INTERFEROMETER NULLER  

International Nuclear Information System (INIS)

We present observations of the 51 Ophiuchi circumstellar disk made with the Keck interferometer operating in nulling mode at N band. We model these data simultaneously with VLTI-MIDI visibility data and a Spitzer IRS spectrum using a variety of optically thin dust cloud models and an edge-on optically thick disk model. We find that single-component optically thin disk models and optically thick disk models are inadequate to reproduce the observations, but an optically thin two-component disk model can reproduce all of the major spectral and interferometric features. Our preferred disk model consists of an inner disk of blackbody grains extending to ?4 AU and an outer disk of small silicate grains extending out to ?1200 AU. Our model is consistent with an inner 'birth' disk of continually colliding parent bodies producing an extended envelope of ejected small grains. This picture resembles the disks around Vega, AU Microscopii, and ? Pictoris, supporting the idea that 51 Ophiuchius may be a ? Pictoris analog.

146

Phase stability measurement of a conventional analog ?-A type low-level RF controller  

International Nuclear Information System (INIS)

For an FEL application and an ERL light source, high-stability of accelerator RF amplitude and phase is required. A low-level RF controller (LLC) of the JAEA-ERL has been improved to ensure high-stability accelerating RF field. The LLC is a conventional analog phi-A type controller with following functions: the feedback gain, loop-offset phase and time constant can be varied during operation to obtain optimum parameters for the high-stability RF field, all the circuits are contained in a temperature controlled oven. The LLC performance is tested for a 499.8 MHz superconducting cavity and a 1300 MHz copper cavity. The phase and amplitude stabilities of the 499.8 MHz superconducting cavity within a 1 ms macro-pulse are 0.0055deg-rms and 7.64x10-5, respectively. For the 1300 MHz copper cavity, pulse mode and CW mode were tested. In the case of pulse mode, the phase and amplitude stabilities are 0.011deg-rms and 7.64x10-5, respectively. In the case of CW mode, the phase and amplitude stabilities are 0.011deg-rms and 6.68x10-5, respectively. (author)

147

Quantitative measurement of local cerebral metabolic rate for glucose utilizing tritiated 2-deoxyglucose  

International Nuclear Information System (INIS)

The [14C]2-deoxyglucose (2-DG) technique has been widely utilized for quantitative measurement of local cerebral metabolic rate for glucose (lCMRG) in animals. The technique as presently used is limited by the energy of 14C beta-particles, which can travel relatively great distances in tissue. This results in limited autoradiographic resolution and in computed 14C concentrations which are a function of tissue section thickness. [3H]2-DG has less energetic beta-particles; hence, autoradiographs have better resolution and optical densities are independent of tissue thickness for sections greater than 5 ?m. The authors have developed a method for quantitation of lCMRG in rats using [3H]2-DG and a newly developed ultrasensitive X-ray film. Autoradiographic tissue standards were prepared by injecting rats with [3H]2-DG and assaying micro-samples of brain for 3H concentration. Ten rats were used in this study. Five rats received [3H]2-DG (300 ?Ci/100 g) and 5 rats received [14C]2-DG (7.5 ?Ci/100 g). The mean lCMRG values for selected areas of the central nervous system demonstrated no significant difference (P > 0.05) between the [14C]2-DG and the [3H]2-DG groups. Values for lCMRG from the [3H]2-DG group showed no variation attributable to inadequate microtome precision. The improved resolution obtained by utilizing [3H]2-DG is especially evident where gray matter (high lCMRG) is immediately adjacent to white matter (low lCMRG). (Auth.)

148

21 CFR 862.1340 - Urinary glucose (nonquantitative) test system.  

Science.gov (United States)

... (a) Identification. A urinary glucose (nonquantitative) test system is a device intended to measure glucosuria (glucose in urine). Urinary glucose (nonquantitative) measurements are used in the diagnosis and...

2010-04-01

149

Use of arterialised venous instead of arterial blood for measurement of myocardial glucose metabolism during euglycaemic-hyperinsulinaemic clamping  

International Nuclear Information System (INIS)

Sampling of arterialised venous blood (AVB) is often used as an alternative to sampling of arterial blood when determining the myocardial metabolic rate of glucose (MRGlu). This method, however, has not yet been validated for measurement of plasma fluorine-18 fluorodeoxyglucose (FDG) activity during a euglycaemic-hyperinsulinaemic clamp (EHC). In this study, dynamic FDG scans were performed with arterial blood sampling during EHC. Samples of arterial and AVB or venous blood were simultaneously withdrawn at five time points for measurement of FDG activity and plasma glucose in 36 patients. Both venous to arterial and AVB to arterial ratios were calculated for FDG activity and plasma glucose. Mean ratios between AVB and arterial FDG activity were then used to create calculated arterialised venous input functions from corresponding arterial input functions. The mean effect of arterialisation on the calculation of Ki was assessed. In nine additional patients, Ki obtained with continuous sampling of AVB was compared with Ki obtained with a corresponding (quality-controlled) image-derived input function from the ascending aorta. Using AVB, measurements of FDG activity were much more reliable than with venous blood sampling. As compared with arterial sampling, however, FDG activity was underestimated early after injection, while it was overestimated after 20 min. In both analyses, AVB resulted in 10%±10% overestimation of Ki. Because of a 5%±5% underestimation of plasma glucose concentration with AVB, the net effect on the final calculation of MRGlu was small (on average 5% overestimation). It is concluded that the use of AVB has a small average effect on the determination of MRGlu. This method does, however, contribute to variability in the results. This variability cannot be explained by different degrees of arterialisation. (orig.)

150

The effects of precision, haematocrit, pH and oxygen tension on point-of-care glucose measurement in critically ill patients: a prospective study.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

BACKGROUND: Critical care glycaemic control protocols commonly have treatment adjustment (target) ranges spanning ?2 mmol/L. These require precise point-of-care glucose measurement, unaffected by other variables, to avoid measurement errors increasing glycaemic variability and hypoglycaemic episodes (both strongly associated with mortality in critically ill patients). METHODS: A prospective 206 intensive care patient study was carried out. Arterial glucose concentrations were measured in du...

Watkinson, Pj; Barber, Vs; Amira, E.; James, T.; Taylor, R.; Young, Jd

2012-01-01

151

Identification and correction of analog-to-digital-converter nonlinearities and their implications for differential absorption lidar measurements.  

Science.gov (United States)

Differential absorption lidar (DIAL) is a powerful remote-sensing technique widely used to probe the spatial and temporal distribution of ozone and other gaseous atmospheric trace constituents. Although conceptually simple, the DIAL technique presents many challenging and often subtle technical difficulties that can limit its useful range and accuracy. One potentially serious source of error for many DIAL experiments is nonlinearity in the analog-to-digital converters used to capture lidar return signals. The impact of digitizer nonlinearity on DIAL measurements is examined, and a simple and inexpensive low-frequency dithering technique that significantly reduces the effects of ADC nonlinearity in DIAL and other applications in which the signal is repetitively averaged is described. PMID:21068953

Langford, A O

1995-12-20

152

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.)

153

Paraxial Ocular Measurements and Entries in Spectral and Modal Matrices: Analogy and Application  

Science.gov (United States)

Lensometers and keratometers yield powers along perpendicular meridians even if the principal meridians of the lens and the cornea are oblique. From each such instrument, multiple raw data represented on optical crosses require conversion to determine elementary statistics. Calculations for research decisions need to be authentic. Principles common to meridians generalize formulaic methods for oblique meridians. Like a lens or a cornea, matrix latent quantities are represented on a matrix cross. Our problem is to determine the matrix whose cross represents quantities on the optical cross. All measurements on an optical cross that include corneal and lens powers and oblique meridians can be considered. Once determined, a portfolio of matrix calculations applies and is justified for ophthalmic calculation. Matrices can be unique and, like a cornea before it is measured, contain latent observations. Asymmetric power component matrices quantify a deviation of a corneal surface from smoothness and toricity. Entries may identify those measurements causing irregular astigmatism that may stem from surgical or other external intervention. Irregular astigmatism is detected primarily from significant measurements in the paraxial range. Measurements are assimilated with matrix factors in a holistic way in order to support choices with calculations and statistics. PMID:25045399

2014-01-01

154

Measurements of urea and glucose in aqueous solutions with dual-beam near-infrared Fourier transform spectroscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study investigates the use of a dual-beam, optical null, FT-IR spectrometer to measure trace organic components in aqueous solutions in the combination band region 5000-4000 cm(-1). The spectrometer may be used for both single- and dual-beam measurements, thereby facilitating comparison of these two modes of operation. The concentrations of aqueous solutions of urea and glucose in the ranges 0-40 mg/dL and 0-250 mg/dL, respectively, were determined by principal component regression using...

Jensen, Peter Snoer; Bak, Jimmy

2002-01-01

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

Noninvasive measurement of plasma glucose from exhaled breath in healthy and type 1 diabetic subjects  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Effective management of diabetes mellitus, affecting tens of millions of patients, requires frequent assessment of plasma glucose. Patient compliance for sufficient testing is often reduced by the unpleasantness of current methodologies, which require blood samples and often cause pain and skin callusing. We propose that the analysis of volatile organic compounds (VOCs) in exhaled breath can be used as a novel, alternative, noninvasive means to monitor glycemia in these patients. Seventeen he...

Minh, Timothy D. C.; Oliver, Stacy R.; Ngo, Jerry; Flores, Rebecca; Midyett, Jason; Meinardi, Simone; Carlson, Matthew K.; Rowland, F. Sherwood; Blake, Donald R.; Galassetti, Pietro R.

2011-01-01

157

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

158

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

159

Digital-to-analog converter with neutron probe for measuring moisture of bulk materials, especially coke  

International Nuclear Information System (INIS)

A block diagram of the converter is given as is its description and the description of its operation according to the block diagram and its calibration. The converter was developed for measuring the moisture of coke in blast furnaces with regard to the requirement for simple maintenance, stability and easy calibration of the instrument. (J.P.)

160

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

CERN Document Server

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 for the GlueX forward calorimeter. For pulses with an amplitude of 100 mV the timing resolution is 0.57 +- 0.18 ns, while for 500 mV pulses it is 0.24 +- 0.08 ns.

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

2010-01-01

 
 
 
 
161

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

International Nuclear Information System (INIS)

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 12-bit sampling depth. All measured time resolutions were better than 1 ns, independent of signal size, which is the design goal for the GlueX forward calorimeter. For pulses with an amplitude of 100 mV the timing resolution is 0.57±0.18 ns, while for 500 mV pulses it is 0.24±0.08 ns.

162

Phototelectric Emission Measurements on the Analogs of Individual Cosmic Dust Grains  

Science.gov (United States)

The photoelectric emission process is considered to be the dominant mechanism for charging of cosmic dust grains in many astrophysical environments. The grain charge and the equilibrium potentials play an important role in the dynamical and physical processes that include heating of the neutral gas in the interstellar medium, coagulation processes in the dust clouds, and levitation and dynamical processes in the interplanetary medium and planetary surfaces and rings. An accurate evaluation of photoelectric emission processes requires knowledge of the photoelectric yields of individual dust grains of astrophysical composition as opposed to the values obtained from measurements on flat surfaces of bulk materials, as it is generally assumed on theoretical considerations that the yields for the small grains are much higher than the bulk values. We present laboratory measurements of the photoelectric yields of individual dust grains of silica, olivine, and graphite of approximately 0.09 to 8 microns radii levitated in an electrodynamic balance and illuminated with W radiation at 120 to 160 nm wavelengths. The measured values and the size dependence of the yields are found to be substantially different from the bulk values given in the literature.

Abbas, Mian M.; Tankosic, D.; Craven, P. D.; Spann, J. F.; LeClair, A.; West, E. A.; Weingartner, J. C.; Tielens, A. G. G. M.; Nuth, J. A.; Camata, R. P.; Gerakines, P. A.

2005-01-01

163

Photoelectric Emission Measurements on the Analogs of Individual Cosmic Dust Grains  

Science.gov (United States)

The photoelectric emission process is considered to be the dominant mechanism for charging of cosmic dust grains in many astrophysical environments. The grain charge and equilibrium potentials play an important role in the dynamical and physical processes that include heating of the neutral gas in the interstellar medium, coagulation processes in the dust clouds, and levitation and dynamical processes in the interplanetary medium and planetary surfaces and rings. An accurate evaluation of photoelectric emission processes requires knowledge of the photoelectric yields of individual dust grains of astrophysical composition as opposed to the values obtained from measurements on flat surfaces of bulk materials, as it is generally assumed on theoretical considerations that the yields for the small grains are much different from the bulk values. We present laboratory measurements of the photoelectric yields of individual dust grains of silica, olivine, and graphite of approx. 0.09-5 micrometer radii levitated in an electrodynamic balance and illuminated with ultraviolet radiation at 120-160 nm wavelengths. The measured yields are found to be substantially higher than the bulk values given in the literature and indicate a size dependence with larger particles having order-of-magnitude higher values than for submicron-size grains.

Abbas, M. M.; Tankosic, D.; Craven, P. D.; Spann, J. F.; LeClair, A.; West, E. A.; Weingartner, J. C.; Tielens, A. G. G. M.; Nuth, J. a.; Camata, R. P.

2006-01-01

164

Error in the measurement of the Telector monitor, model 6112B (analogic)  

International Nuclear Information System (INIS)

This monitor is a portable equipment used with radiological protection ends in many areas where use of radioactive material is made, since account with a telescopic bar with two Geiger Mueller tubes (GM) to measure gamma radiation. The maker in his specifications indicates that the equipment is able to measure from 0.1 R/hr up to 1000 R/hr and their response doesn't depend on the energy in the interval of 300 keV to 3 MeV. However, personal of the Electronic Systems department carrying out tests in the Secondary Laboratory of Dosimetric Calibration (LSCD) of the ININ, it found that this monitor really presents an energy dependence for the energies of 60Co, in the scale of 2 R/hr. With base in an analysis of the equipment and the two GM detectors that it uses, was found that the origin of the problem is the point of saturation of the detector that uses for this scale, which coincides with the maximum measurement value that is of 2 R/hr. This flaw it can be solved using the detector that operates with the high scales, for which is required to make a modification to the electronic circuit in the part of the switch that selects the detector type. (Author)

165

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

166

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

167

Tetrachlorofluorescein TInsP as a Substrate Analog Probe for Measuring Phytase Activity in Surface Water: Proof of Concept.  

Science.gov (United States)

An innovative approach for measuring phytase activity (PA) in surface water is presented. A substrate analog of -inositol hexakis(dihydrogen) phosphate (InsP), commonly referred to as phytic acid, 1--5--(1-oxo-1-(2' ,4,7,7' -tetrachloro-3',6'-dihydroxy-3-oxo-3H-spiro[isobenzofuran-1,9'-xanthen]-6-yl)-5,8,11-trioxa-2-azatridecan-13-yl)-inositol 1,2,3,4,6-pentakis--(dihydrogen) phosphate, referred to as tetrachlorofluorescein (TET) tethered (T)InsP, has been developed that can be used to monitor the (phytase-catalyzed) phosphate ester bond-cleavage reaction. Test phytases, (wheat [4-] and [3-] phytase) sequentially remove phosphate groups from TET TInsP, producing dephosphorylated probe species that were readily separated by reversed-phase high-performance liquid chromatography (RP-HPLC). Because dephosphorylated probe species retain the TET group, highly sensitive quantification could be achieved using fluorescence detection (excitation/emission ' = 245/540 nm). Calibration curves for TET TInsP, which could be used as a standard for quantifying all probe species, were linear ( > 0.999) over the range of concentrations tested. Phytase-generated dephosphorylated probe species were characterized or identified using RP-HPLC with mass spectrometry. Results of mass spectrometry analysis show that the RP-HPLC system was capable of distinguishing between dephosphorylated probe species at the regioisomeric level. The TET TInsP molecular probe was used to successfully measure PA in pond water. We found that the PA associated with the particulate plus water-soluble fraction was greater than that observed for the water-soluble fraction alone. Moreover, it appeared that 4- and 3-phytase were active in pond water based on an analysis of the chromatographic profile (i.e., elution sequence) of dephosphorylated probe species produced. The advent of a fluorescent substrate analog of InsP affords environmental scientists with the means to unambiguously quantify an extremely small amount of phytase-generated dephosphorylated product(s), enabling the measurement of PA over a reasonably short time duration, in an environmental sample containing low concentrations of enzyme. PMID:23673739

Berry, Duane F; Harich, Kim

2013-01-01

168

Measurement of the polarization of neutrons from (p,n) reactions at isobaric analog resonances  

International Nuclear Information System (INIS)

Measurements were made of the polarization of neutrons from the 51V(p,n)51Cr and 55Mn(p,n)55Fe reactions at proton energies corresponding to isobaric analogue resonances. For the first reaction in the vicinity of the IAR at E/sub p/ equals 2.335 MeV the polarization excitation function (lab angle of 500) was similar in shape to the yield curve; the maximum value of P was +12 percent and occurred at the resonance energy. Polarization values ranged between -6 percent and +12 percent for several scattering angles and proton energies. The 55Mn(p,n)55Fe results indicate small non-zero values of neutron polarization for nearly all values of E/sub p/, and with the variation of polarization with energy and scattering angle being generally structureless. The R-matrix theory of nuclear reactions was used with certain simplifying assumptions to describe the energy behavior, angular distributions, and polarizations in the vicinity of the 2.335 MeV IAR of the 51V(p,n)51Cr reaction. The model was able to fit the yield curve, but only partially successful in describing the variation of polarization with energy across the resonance. A study is made of the conditions on the scattering matrix elements for a number of choices of J/sup ?/ for the 2.335 MeV resonance and the less prominent nearby 2.345 MeV resonance

169

A multiplicative analogical moiré phase-shifting Twyman-Green technique for Nd:YAG rod wavefront distortion measurement  

Science.gov (United States)

Nd:YAG rod wavefront distortion has been quantified in a Twyman-Green interferometer which employs the multiplicative analogical moiré phase-shifting method for demodulation. The measuring procedure is based on the superimposition of a transmission grating located outside the interferometric module with a phase modulated high-frequency Twyman-Green spatial carrier. Later, a set of fringe patterns, provided by low-pass filtering of the phase-shifted multiplicative moiré patterns obtained, is combined in a generic phase-shifting algorithm (GPSA). The interesting test information is achieved once the previous procedure has been carried out with and without the transparent object located in the measuring area. The wavefront distortion (WFD) is calculated by the subtraction of these results provided by the GPSA, or directly if a differential phase-shifting algorithm (DPSA) is employed. The WFD obtained is in accordance with characteristics of the test object. The comparison of the results obtained with both families of algorithms provides information about the sensitivities to error sources of the DPSA employed. A first approximation to the analysis of significant error sources of DPSAs is presented.

Dorrío, B. V.; Cernadas, D.; Trillo, C.; Doval, A. F.; López, C.; Pérez-Amor, M.; Fernández, J. L.

2001-01-01

170

Analog-to-digital interface and real-time measurement of the phase volume of a beam using an ''elektronika-1001'' computer  

International Nuclear Information System (INIS)

The authors describe a system for multichannel exchange of analog and digital signals between an Elektronika 100I computer and experimental hardware via noise-immune connecting lines. Diagrams illustrate the analog-to-digital interface and the connections between that interface and a multiwire secondary-emission profile detector. The dynamic measurement range of the system is 1-10-4 pC per wire. Analog and digital data are input at 12.5 kHz and 30 kHz respectively. The time required to analyze the beam shape and make corrections is 150 microseconds. The geometric parameters of the beam are measured accurately to 20 micrometers. The angular divergence of the beam is 10-4 rad

171

Comparative measurement of regional blood flow, oxygen and glucose utilisation in soft tissue tumour of rabbit with positron imaging  

International Nuclear Information System (INIS)

C15O2 and 15O2 steady state techniques were used to measure regional blood flow (RBF) and regional oxygen utilisation (ROU) in a rabbit tumour model. RBF values were 4.6+-0.6 ml min/100 cc for normal muscle tissue and 11.0+-3.0 ml/min/100 cc for tumour surface. Corresponding values for ROU were 18.3+-3.5 ?mol/min/100 cc for normal tissue and 39.7+-20.1 ?mol/min/100 cc for tumour surface. 18F-2-fluoro-2-deoxy-D-glucose (2FDG) was used in the same model to measure glucose metabolic rate. The values obtained were 4.3+-2.1 ?mol/min/100 cc for normal muscle and 53.8+-18.3 ?mol/min/100 cc for tumour tissue. Tumour-to-muscle ratios increased more rapidly with time for 2FDG than for oxygen utilisation and blood flow. The effect of radiation on tumour and normal tissue was followed by measurements of RBF and ROU. RBF values increased both in tumour and normal muscle tissue during radiation and decreased during one week after radiation. ROU-values decreased (30%) in tumour and increased (45%) in normal muscle tissue during radiation. One week after radiation, ROU-values were 30% lower in tumour and 45% higher in normal muscle tissue. (U.K.)

172

21 CFR 862.1345 - Glucose test system.  

Science.gov (United States)

...1345 Glucose test system. (a) Identification. A glucose test system is a device intended to measure glucose quantitatively in blood and other body fluids. Glucose measurements are used in the diagnosis and treatment of...

2010-04-01

173

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

174

Involvement of kinases in glucose and fructose uptake by Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Uptake of glucose, fructose, and the nonmetabolizable analog 6-deoxyglucose was measured in wild-type Saccharomyces cerevisiae and two mutant strains, one (hxk1 hxk2) lacking both hexokinase A(P-I) and B(P-II) but containing glucokinase (and hence able to grow on glucose but not fructose) and the other (hxk1 hxk2 glk) also lacking glucokinase (and not able to grow on glucose either). Uptake of the nonmetabolized substances (i.e., 6-deoxyglucose in all three strains, fructose in the two mutant...

Bisson, L. F.; Fraenkel, D. G.

1983-01-01

175

Measurements of urea and glucose in aqueous solutions with dual-beam near-infrared Fourier-transform spectroscopy  

DEFF Research Database (Denmark)

This study investigates the use of a dual-beam, optical null, FT-IR spectrometer to measure trace organic components in aqueous solutions in the combination band region 5000-4000 cm(-1). The spectrometer may be used for both single- and dual-beam measurements, thereby facilitating comparison of these two modes of operation. The concentrations of aqueous solutions of urea and glucose in the ranges 0-40 mg/dL and 0-250 mg/dL, respectively, were determined by principal component regression using both modes. The dual-beam technique eliminated instrumental variations present in the single-beam measurements that must be taken into account when quantifying trace components from single-beam spectra. The data obtained with the dual-beam technique resulted in more stable calibration models based on principal component regression. These calibration models need fewer factors and yield lower prediction errors than those based on traditional single-beam data.

Jensen, P.S.; Bak, J.

2002-01-01

176

Effects of nutrition?s carbohydrate content on the metabolism of pregnant women by means of indirect calorimetry, bioelectrical impedance analysis and blood glucose measurements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective: Since recommendations for nutrition in pregnancy are varying widely we assessed the effects of two diets differing in percentages of carbohydrates (CH). We measured resting energy expenditure (REE) and proportional use of macronutrients by indirect calorimetry (IC), body composition by bioelectrical impedance analysis (BIA) as well as blood glucose. Womens? carbohydrate tolerance was determined by oral glucose tolerance test (oGTT) applying O?Sullivan?s criteria in order to be a...

Brandt, Katrin

2010-01-01

177

Radioimmunoassay for octapeptide analogs of somatostatin: Measurement of serum levels after administration of long-acting microcapsule formulations  

International Nuclear Information System (INIS)

The development of a long-acting delivery system for D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2 (RC-160), an octapeptide analog of somatostatin, required the establishment of a method for determining the concentration of this analog in serum during treatment. A sensitive and specific radioimmunoassay (RIA) for RC-160 was developed and used for following the rate of liberation of this peptide from microcapsules of poly(DL-lactide-coglycolide). Antibodies were generated in a rabbit against RC-160 conjugated to bovine serum albumin with glutaraldehyde. At an antiserum dilution of 1:100,000, the antibodies bound approximately 25% of added radiolabeled RC-160. Somatostatin octapeptide analogs that had a disulfide bridge showed crossreactivity with the antiserum, but analogs without the disulfide bridge and other peptides tested did not crossreact. The minimum detectable dose of RC-160 was 10 pg. Intra- and interassay coefficients of variation ranged from 9.1% to 12.8% and from 14% to 30%, respectively. The RIA was suitable for direct determination of RC-160 in serum. Eleven prototype batches of microcapsules were tested in rats, and the rate of release of the analog from the microcapsules was followed. An improved batch of microcapsules made from RC-160 pamoate maintained high serum levels of RC-160 for more than 30 days after intramuscular injection. The RIA should be of value for monitoring levels of this analog in serum during long-term therapyduring long-term therapy

178

Dielectric and Hardness Measurements of Martian Analog Rocks in Support of the WISDOM Radar on ExoMars  

Science.gov (United States)

The success of the WISDOM (Water Ice and Subsurface Deposit Observation On Mars) radar in supporting the ExoMars drill to targets of opportunities and for maintaining optimal drilling capabilities is based on the complementarily of the two experiments in assessing the shallow subsurface physical properties. The dielectric properties as inverted from WISDOM wide-band ground penetrating radar radargrams, will be used to assess the ground mechanical properties as rock hardness, density and porosity which are crucial inputs for optimizing drilling operations. The main purpose of this research is to perform dielectric permittivity and hardness measurements for Martian analog rocks as a function of the Martian surface environmental parameters in an attempt to correlate between the physical and mechanical properties (i.e. dielectric constant and rock hardness) for volcanic rocks and permafrost simulating the case of the most upper layers of the Martian regolith. The implication for optimizing ExoMars drilling and sampling activities based on this correlation between the physical and mechanical properties will be discussed. We considered eight different types of volcanic rocks, for which we measured both the permittivity at the frequency band 200 to 1500 MHz and hardness over the range R= 10 to 100 using Schmidt hammer hardness tester. Based on our experimental results, the dielectric constant and hardness values ranged from (? = 1.91 to 8.09) and (R = 12.8 to 68) at the density of (? = 0.78 to 3 gm cm-3) for pumice and flood basalt respectively. Dielectric constant and rock hardness are found to increase with increasing sample density which implied a direct linear correlation between dielectric constant and rock hardness. The drill penetration rate of the previously described samples is predicted and correlated to the dielectric constant. An inverse relation between dielectric constant and drill penetration rate is concluded.

ElShafie, A.; Heggy, E.; Ciarletti, V.; Clifford, S. M.

2011-12-01

179

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-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions. (orig.)

180

Avaliação de dois sensores portáteis para mensuração da glicemia em cães Evaluation of two portable meters for blood glucose measurements in dogs  

Directory of Open Access Journals (Sweden)

Full Text Available Avaliou-se a precisão analítica e clínica de dois sensores portáteis para mensuração da glicemia em cães. Os valores da mensuração da glicemia obtidos com os sensores foram comparados com aqueles obtidos pelo método padrão da glicose oxidase, por meio da análise de correlação e da análise da grade de erros. Os resultados gerados pelos sensores não foram diferentes do método padrão. Conclui-se que ambos os sensores são adequados para mensuração da glicemia em cães.The clinical and analytical accuracy of two portable meters for glucose measurement in dogs was evaluated. Blood glucose values obtained by the use of portable meters were compared to those obtained using the glucose oxidase reference method, by means of correlation and error analysis. Results obtained with the blood glucose meters were not different from those obtained with the reference method. Both apparatus evaluated are adequate for use in dogs.

K. Bluwol

2007-12-01

 
 
 
 
181

The influence of image resolution on the positron emission tomographic measurement of caudate glucose consumption  

International Nuclear Information System (INIS)

The aim of this study was to investigate the influence of image resolution on (a) relative and absolute values of caudate glucose consumption (rCMRGlc) determined by positron emission tomography (PET), and (b) the detection of significant differences in these metabolic values between groups of subjects. For this purpose, raw data of cerebral accumulation of fluorine-18 fluorodeoxyglucose (FDG) obtained in 11 normal subjects and in nine patients with unilateral thalamic infarction were reconstructed using filtered backprojection with four different cut-off frequencies (CFs), yielding images with a transaxial resolution of 5.7, 7.1, 8.9 and 11 mm (full-width at half-maximum; FWHM). Absolute values of candate rCMRGls decreased significantly by more than 30% over the range of image resolutions studied. Bilateral ratios of caudate rCMRGls were insensitive to variations in image resolution. Levels if significance assessing the differences in mean metabolic values between patients and controls were all below 0.01. They were, however, slightly better at image resolutions of 7,1 and 8.9 mm than at a resolution of 5.7 mm. These data indicate (a) that relative values of rCMRGls are better suited to compare quantitative results from different PET cameras than are absolute values, and (b) that th CF used for the filtered backprojection exerts a small but not negligible influence on levels of significance assessing differences in metabolic values between groups of subjects. (orig.)

182

Measurement of local glucose transport rate constant and free glucose pool in human brain using PET and CMG: First result in normals and Huntington patients  

International Nuclear Information System (INIS)

Even in images reconstructed with the method of filtered backprojection it is possible to perform parametric images on a pixel by pixel base with use of appropriate stable algorithms. There is no doubt, that these analytical procedures are less efficient than the iterative ones, but they are doing well when relative values between pixels are of interest. The approach using a Lookup-Table was determined to be best and used in normals and Huntington patients. The first results show that in Huntington patients the transport of glucose is not regional affected, but globally reduced. Following studies on a large patient pool will challenge and proceed further this presented technique. (orig.)

183

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

184

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.

185

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

186

Measurement of insulin-mediated glucose uptake: Direct comparison of the modified insulin suppression test and the euglycemic, hyperinsulinemic clamp  

Science.gov (United States)

Background Two direct measurements of peripheral insulin sensitivity are the M value derived from the euglycemic, hyperinsulinemic clamp (EC) and the steady-state plasma glucose (SSPG) concentration derived from the insulin suppression test (IST). Prior work suggests that these measures are highly correlated, but the agreement between them is unknown. To determine the agreement between SSPG and M and to develop transformation equations to convert SSPG to M and vice versa, we directly compared these two measurements in the same individuals. Methods A total of 15 nondiabetic subjects (9 women and 6 men) underwent both an EC and a modified version of the IST within a median interval of 5 days. We performed standard correlation metrics of the two measures and developed transformation regression equations for the two measures. Results The mean ± SD age of the subjects was 57 ± 7 years and body mass index, 27.7 ± 3.9 kg/m2. The median (interquartile range) SSPG concentration was 6.7 (5.1, 9.8) mmol/L and M value, 49.6 (28.9, 64.2) ?mol/min/kg-LBM. There was a highly significant correlation between SSPG and M (r = ?0.87, P <0.001). The relationship was best fit by regression models with exponential/logarithmic functions (R2 = 0.85). Bland-Altman plots demonstrated an excellent agreement between these measures of insulin action. Conclusion The SSPG and M are highly related measures of insulin sensitivity and the results provide the means to directly compare the two measurements. PMID:23151437

Knowles, Joshua W.; Assimes, Themistocles L.; Tsao, Philip S.; Natali, Andrea; Mari, Andrea; Quertermous, Thomas; Reaven, Gerald M.; Abbasi, Fahim

2014-01-01

187

Skeletal muscle blood flow measured by Rb-82 during changes in plasma glucose  

International Nuclear Information System (INIS)

The purpose of this work was to assess the feasibility of measuring skeletal muscle blood flow with the K+ analogue Rb-82. Flow measurements were made in the thigh muscle of anesthetized rabbits after simultaneous sortic injection of radiolabeled microspheres (15?m diam) and a bolus of Rb-82. Estimates of flow as determined by Rb-82 were based on peak tissue uptake and arterial concentration achieved over 150 sc post injection and the assumption that the extraction fraction of Rb-82 in resting muscle is unity. No significant difference was found between the microsphere and Rb-82 methods. Flow estimates were an average of 18% higher with the Rb-82 method. However, the rubidium method showed less variability since the ratio of standard deviation to the mean flow ranged from .23 to .46 compared to a ratio of .47 to .56 for the microsphere method. The values for mean flow and its variability are consistent with previously published reports on blood flow measurements in the resting skeletal muscle of the anesthetized rabbit. This study suggests that valid measurements of skeletal muscle blood flow can be made using positron emitting radionuclides

188

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

189

An Analog Front-End and ADC Integrated Circuit for Implantable Force and Orientation Measurements in Joint Prosthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents an analogue front-end and ADC integrated circuit for processing signals of sensors implanted into joint prosthesis. The circuit is designed to be operated with Wheatstone bridge sensors, such as strain gauges, pressure, Hall Effect, magneto-resistive sensors, etc. It performs sensor supply multiplexing, sensor signal amplification with chopper modulation, offset compensation and 14-bit analog to digital conversion in a single chip. It can operate simultaneously up to eight ...

Godara, Balwant; Nikita, Konstantina S.; Tanner, Steve; Ali, Shafqat; Banjevic, Mirjana; Arami, Arash; Aminian, Kamiar; Hasenkamp, Willyan; Bertsch, Arnaud; Renaud, Philippe; Farine, Pierre-andre?

2013-01-01

190

Direct measurements of blood glucose concentration in the presence of saccharide interferences using slope and bias orthogonal signal correction and Fourier transform near-infrared spectroscopy  

Science.gov (United States)

Saccharide interferences such as Dextran, Galactose, etc. have a great potential to interfere with near infrared (NIR) glucose analysis since they have a similar spectroscopic fingerprint and are present physiologically at large relative concentrations. These can lead to grossly inappropriate interpretation of patient glucose levels and resultant treatment in critical care and hospital settings. This study describes a methodology to reduce this effect on glucose analysis using an NIR Fourier transform spectroscopy method combined with a multivariate calibration technique (PLS) using preprocessing by orthogonal signal correction (OSC). A mathematical approach based on the use of a single calibration based bias and slope correction was applied in addition to a standard OSC was investigated. This approach is combined with a factorial interferent calibration design to accommodate for interference effects. We named this approach as a slope and bias OSC (sbOSC). sbOSC differs from OSC in the way it handles the prediction. In sbOSC, statistics on slope and bias obtained from a set of calibration samples are then used as a validation parameter in the prediction set. Healthy human volunteer blood with different glucose (80 to 200 mg/dL) and hematocrit (24 to 48 vol.%) levels containing high expected levels of inteferents have been measured with a transmittance near-infrared Fourier transform spectrometer operates in the broadband spectral range of 1.25-2.5 ?m (4000-8000 cm-1). The effect of six interferents compounds used in intensive care and operating rooms, namely Dextran, Fructose, Galactose, Maltose, Mannitol, and Xylose, were tested on blood glucose. A maximum interference effect (MIE) parameter was used to rank the significance for the individual interferent type on measurement error relative to the total NIR whole blood glucose measurement error. For comparison, a YSI (Yellow Springs Instrument) laboratory reference glucose analyzer and NIR data were collected at the same time as paired samples. MIE results obtained by sbOSC were compared with several standard spectral preprocessing approaches and show a substantial reduced effect of saccharide interferences. NIR glucose measurement results are substantially improved when comparing standard error of prediction from validation samples; and resulting MIE values are small.

Abookasis, David; Workman, Jerome J.

2011-02-01

191

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

192

Glucose allostasis  

DEFF Research Database (Denmark)

In many organisms, normoglycemia is achieved by a tight coupling of nutrient-stimulated insulin secretion in the pancreatic beta-cell (acute insulin response [AIR]) and the metabolic action of insulin to stimulate glucose disposal (insulin action [M]). It is widely accepted that in healthy individuals with normal glucose tolerance, normoglycemia can always be maintained by compensatorily increasing AIR in response to decreasing M (and vice versa). This has been mathematically described by the hyperbolic relationship between AIR and M and referred to as glucose homeostasis, with glucose concentration assumed to remain constant along the hyperbola. Conceivably, glucose is one of the signals stimulating AIR in response to decreasing M. Hypothetically, as with any normally functioning feed-forward system, AIR should not fully compensate for worsening M, since this would remove the stimulus for the compensation. We provide evidence from cross-sectional, longitudinal, and prospective data from Pima Indians (n = 413) and Caucasians (n = 60) that fasting and postprandial glucose concentrations increase with decreasing M despite normal compensation of AIR. For this physiologic adaptation to chronic stress (insulin resistance), we propose to use the term "glucose allostasis." Allostasis (stability through change) ensures the continued homeostatic response (stability through staying the same) to acute stress at some cumulative costs to the system. With increasing severity and over time, the allostatic load (increase in glycemia) may have pathological consequences, such as the development of type 2 diabetes.

Stumvoll, Michael; Tataranni, P Antonio

2003-01-01

193

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

194

Measurement of proliferation and disappearance of regulatory T cells in human studies using deuterium-labeled glucose.  

Science.gov (United States)

The in vivo proliferation and disappearance kinetics of lymphocytes may be estimated in humans from rates of deuterium-labeled glucose ((2)H(2)-glucose) incorporation into DNA. This protocol describes its application to regulatory T cells (Treg). Because Treg divide frequently, (2)H(2)-glucose is a suitable precursor, achieving high levels of enrichment over a short period. Being nonradioactive and readily administered, it is appropriate for human studies.There are four phases to the method: labeling, sampling, analysis and modeling. Labeling consists of administration of (2)H(2)-glucose, either intravenously or orally; during this phase, small blood samples are taken to monitor plasma glucose enrichment. Sampling occurs over the ensuing ?3 weeks; PBMC are collected and sorted according to surface marker expression. Cell separation can be achieved by fluorescence-activated cell sorting (FACS) using CD4, CD45RA and CD25 to define memory Treg (CD4(+)CD25(hi)), or by a combination of magnetic bead separation and FACS. Analysis consists of DNA extraction, hydrolysis, derivatization to the pentafluoro tri-acetate (PFTA) derivative, and quantitation of deuterium content by gas-chromatography mass-spectrometry (GC/MS). The ratio of deuterium enrichment in cellular DNA relative to plasma glucose is used to derive the fraction of new cells in the sorted population, and this is modeled as a function of time to derive proliferation and disappearance kinetics. PMID:21287340

Vukmanovic-Stejic, Milica; Zhang, Yan; Akbar, Arne N; Macallan, Derek C

2011-01-01

195

Glucose Tests  

Science.gov (United States)

... tries to restore the balance, both by increasing insulin production and by eliminating excess glucose in the urine. ... is a group of disorders associated with insufficient insulin production and/or a resistance to insulin. People with ...

196

Glucose Dependency of the Metabolic Pathway of HEK 293 Cells Measured by a Flow-through Type pH/CO2 Sensor System Using ISFETs  

Science.gov (United States)

Our group previously reported the application of a flow-through type pH/CO2 sensor system designed to evaluate the metabolic activity of cultured cells. The sensor system consists of two ion-sensitive field effect transistors (ISFETs), an ISFET to measure the total pH change and an ISFET enclosed within a gas-permeable silicone tube to measure the pH change attributable to CO2. In that study, we used the system to quantitatively analyze metabolic switching induced by glucose concentration changes in three cultured cell types (bovine arterial endothelium cell (BAEC), human umbilical vein endothelium cell (HUVEC), and rat cardiomuscle cell (RCMC)), and to measure the production rates of total carbonate and free lactic acid in the cultured cells. In every cell type examined, a decrease in the glucose concentration led to an increase in total carbonate, a product of cellular respiration, and a decrease of free lactic acid, a product of glycolysis. There were very significant differences among the cell types, however, in the glucose concentrations at the metabolic switching points. We postulated that the cell has a unique switching point on the metabolic pathway from glycolysis to respiration. In this paper we use our sensor system to evaluate the metabolic switching of human embryonic kidney 293 cells triggered by glucose concentration changes. The superior metabolic pathway switched from glycolysis to respiration when the glucose concentration decreased to about 2 mM. This result was very similar to that obtained in our earlier experiments on HUVECs, but far different from our results on the other two cells types, BAECs and RCMCs. This sensor system will be useful for analyzing cellular metabolism for many applications and will yield novel information on different cell types.

Yamada, Akira; Mohri, Satoshi; Nakamura, Michihiro; Naruse, Keiji

197

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

198

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

199

Avaliação de dois sensores portáteis para mensuração da glicemia em cães / Evaluation of two portable meters for blood glucose measurements in dogs  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Avaliou-se a precisão analítica e clínica de dois sensores portáteis para mensuração da glicemia em cães. Os valores da mensuração da glicemia obtidos com os sensores foram comparados com aqueles obtidos pelo método padrão da glicose oxidase, por meio da análise de correlação e da análise da grade d [...] e erros. Os resultados gerados pelos sensores não foram diferentes do método padrão. Conclui-se que ambos os sensores são adequados para mensuração da glicemia em cães. Abstract in english The clinical and analytical accuracy of two portable meters for glucose measurement in dogs was evaluated. Blood glucose values obtained by the use of portable meters were compared to those obtained using the glucose oxidase reference method, by means of correlation and error analysis. Results obtai [...] ned with the blood glucose meters were not different from those obtained with the reference method. Both apparatus evaluated are adequate for use in dogs.

K., Bluwol; R., Duarte; M.D., Lustoza; D.M.N., Simões; M.M., Kogika.

200

TD-1HNMR measurements show enantioselective dissociation of ribose and glucose in the presence of H2(17)O.  

Science.gov (United States)

We used Time Domain (1)H Nuclear Magnetic Resonance (NMR) to characterize changes in proton exchange between water and sugar enantiomers at different concentrations of H(2)(17)O (approximately 15-450 mM) and found that dissociation of the (-)-enantiomers of glucose and ribose occurs at significantly higher rates at higher concentrations of H(2)(17)O. The mechanism behind this enantioselective effect is unclear. The hypothesis we propose is that the large magnetic field (B(o) approximately 0.6T) applied during NMR measurements induces electric moments opposite in sign for the D and L-isomers. Because (17)O has a nuclear electric quadrupole moment not = 0, asymmetrically hydrated complexes may form between the B(o)-polarized enantiomers and H(2)(17)O. Either H(2)(17)O is more often hydrating the (+) than the (-)-enantiomers--and consequently pK differences between H(2)(16)O and H(2)(17)O lead to differences in proton exchange between enantiomers and water--or the orientation of H(2)(17)O relative to the B(o)-polarized enantiomers is different, in total or in part, which leads to hydrated complexes with different spatial geometries and different proton exchange properties. This effect is significant for Magneto-Chiral Stereo-Chemistry (MCSC) and astrobiology, and it may help us better understand specific instances of mass independent isotopic fractionation and aid in the development of new technologies for chiral and isotopic separation. PMID:17963473

Scorei, Romulus Ion; Cimpoia?u, Vily Marius; Popa, Radu

2007-10-01

 
 
 
 
201

Backbone dynamics of the Bacillus subtilis glucose permease IIA domain determined from 15N NMR relaxation measurements.  

Science.gov (United States)

The backbone dynamics of the uniformly 15N-labeled IIA domain of the glucose permease of Bacillus subtilis have been characterized using inverse-detected two-dimensional 1H-15N NMR spectroscopy. Longitudinal (T1) and transverse (T2) 15N relaxation time constants and steady-state (1H)-15N NOEs were measured, at a spectrometer proton frequency of 500 MHz, for 137 (91%) of the 151 protonated backbone nitrogens. These data were analyzed by using a model-free dynamics formalism to determine the generalized order parameter (S2), the effective correlation time for internal motions (tau e), and 15N exchange broadening contributions (Rex) for each residue, as well as the overall molecular rotational correlation time (tau m). The T1 and T2 values for most residues were in the ranges 0.45-0.55 and 0.11-0.15 s, respectively; however, a small number of residues exhibited significantly slower relaxation. Similarly, (1H)-15N NOE values for most residues were in the range 0.72-0.80, but a few residues had much smaller positive NOEs and some exhibited negative NOEs. The molecular rotational correlation time was 6.24 +/- 0.01 ns; most residues had order parameters in the range 0.75-0.90 and tau e values of less than ca. 25 ps. Residues found to be more mobile than the average were concentrated in three areas: the N-terminal residues (1-13), which were observed to be highly disordered; the loop from P25 to D41, the apex of which is situated adjacent to the active site and may have a role in binding to other proteins; and the region from A146 to S149. All mobile residues occurred in regions close to termini, in loops, or in irregular secondary structure. PMID:1316146

Stone, M J; Fairbrother, W J; Palmer, A G; Reizer, J; Saier, M H; Wright, P E

1992-05-12

202

Glucose-based spiro-heterocycles as potent inhibitors of glycogen phosphorylase.  

Science.gov (United States)

Glucopyranosylidene-spiro-1,4,2-oxathiazoles were prepared in high yields by NBS-mediated spiro-cyclization of the corresponding glucosyl-hydroximothioates. In an effort to synthesize analogous glucopyranosylidene-spiro-1,2,4-oxadiazolines, with a nitrogen atom instead of the sulphur, attempted cyclizations resulted in aromatization of the heterocycle with opening of the pyranosyl ring. Enzymatic measurements showed that some of the glucose-based inhibitors were active in the micromolar range. The 2-naphthyl-substituted 1,4,2-oxathiazole displayed the best inhibition against RMGPb (K(i)=160 nM), among glucose-based inhibitors known to date. PMID:19574053

Nagy, Veronika; Benltifa, Mahmoud; Vidal, Sébastien; Berzsényi, Eszter; Teilhet, Cathie; Czifrák, Katalin; Batta, Gyula; Docsa, Tibor; Gergely, Pál; Somsák, László; Praly, Jean-Pierre

2009-08-01

203

Credibility of measurement of fructosamine and hemoglobin A1C in estimating blood glucose level of diabetic patients with thalassemia major  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background and Aim: Patients with thalassemia major are classified in high risk group for diabetes mellitus, and therefore monitoring blood glucose level has a vital importance in these people. As high fetal hemoglobin level in thalassemia patients interferes with measurement of glycosylated hemoglobin (hemoglobin A1C), fructosamine evaluation as an alternative approach is suggested.Materials and Methods: This descriptive study was carried out on 33 diabetes mellitus patients with beta-thalas...

Mehrnoush Kosaryan; Mohammad Reza Mahdavi; Ayli Aliasgharian; Masoumeh Mousavi; Payam Roshan

2012-01-01

204

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)

205

Assessment of skeletal muscle blood flow and glucose metabolism with positron emitting radionuclides  

International Nuclear Information System (INIS)

The potassium analog, Rb-82 was used to measure skeletal muscle blood flow and the glucose analog, 18-F-2-deoxy-2-fluoro-D-glucose (FDG) was used to examine the kinetics of skeletal muscle transport and phosphorylation. New Zealand white rabbits' blood flow ranged from 1.0-70 ml/min/100g with the lowest flows occurring under baseline conditions and the highest flows were measured immediately after exercise. Elevated plasma glucose had no effect on increasing blood flow, whereas high physiologic to pharmacologic levels of insulin doubled flow as measured by the radiolabeled microspheres, but a proportionate increase was not detected by Rb-82. The data suggest that skeletal muscle blood flow can be measured using the positron emitting K+ analog Rb-82 under low flow and high flow conditions but not when insulin levels in the plasma are elevated. This may be due to the fact that insulin induces an increase in the Na+/K+-ATPase activity of the cell indirectly through a direct increase in the Na+/H+pump activity

206

A CAMAC unit for charge measuring and pulse shape recording based on a fast, 8-bit parallel analog-to-digital converter  

International Nuclear Information System (INIS)

A device designed mainly for measuring systems for testing parameters of some type of detectors used in the high energy physics is described. The device is one-module CAMAC unit. It is equipped in a fast, 8-bit parallel analog-to-digital converter ''flash''type with a gated integrator at the input and a static RAM (4096 x 8 bit) at the output. The device enables measurements of the charge in pulses from detectors or registration of the shape of these pulses. The construction, operation and parameters of the circuits of the device are described and the way of programming functions using CAMAC dataway is given. 8 refs., 9 figs. (author)

207

Compare analysis of efficiency of using of digital and analog regimes of registration of radiation in radiometric systems of radiation thickness measuring  

CERN Document Server

A consideration is given to the problem of selecting optimized methods of radionuclide radiation registration during the control of the objects with essential changes in thickness. Adequate model of information signal formation is developed and analyzed for the case of the existence of an inertial link of the system with the dead time of a noncontinued type. The boundary values of radiation thickness and radiation flux intensity that divide the priority of using either digital or analog registration modes are revealed. The method is found for the full correction of a systematic error of flux intensity measurement because of the dead time of the apparatus. To control the objects with essential variation of thickness the method of selective measurement of radiation intensity is proposed

Nedavnij, O I

2002-01-01

208

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

209

21 CFR 862.1340 - Urinary glucose (nonquantitative) test system.  

Science.gov (United States)

...glucose in urine). Urinary glucose (nonquantitative) measurements are used in the diagnosis and treatment of carbohydrate metabolism disorders including diabetes mellitus, hypoglycemia, and hyperglycemia. (b) Classification. Class...

2010-04-01

210

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

211

Comparison of a human portable glucometer and an automated chemistry analyzer for measurement of blood glucose concentration in pet ferrets (Mustela putorius furo).  

Science.gov (United States)

This study compared blood glucose concentrations measured with a portable blood glucometer and a validated laboratory analyzer in venous blood samples of 20 pet ferrets (Mustela putorius furo). Correlation and agreement were evaluated with a Bland-Altman plot method and Lin's concordance correlation coefficient. Blood glucose concentrations measured with the laboratory analyzer and the glucometer ranged from 1.9 to 8.6 mmol/L and from 0.9 to 9.2 mmol/L, respectively. The glucometer had a poor agreement and correlation with the laboratory analyzer (bias, -0.13 mmol/L; level of agreement, -2.0 to 3.6 mmol/L, concordance correlation coefficient 0.665). The relative sensitivity and specificity of the portable blood glucometer for detection of hypoglycemia were 100% (95% CI: 66% to 100%) and 50% (95% CI: 20% to 80%), respectively. Positive and negative predictive values were 67% (95% CI: 39% to 87%) and 100% (95% CI: 46% to 100%), respectively. Based on these results, clinicians are advised to be cautious when considering the results from this handheld glucometer in pet ferrets, and blood glucose concentrations should be determined with a laboratory analyzer validated for this species. PMID:25183894

Summa, Noémie M; Eshar, David; Lee-Chow, Bridget; Larrat, Sylvain; Brown, Dorothy C

2014-09-01

212

Noninvasive measurement of blood flow, oxygen consumption, and glucose utilization in the same brain regions in man by positron emission tomography: concise communication  

International Nuclear Information System (INIS)

Local cerebral blood flow (CBF), oxygen consumption (CMRO2), and glucose utilization (CMR-Glc) have been measured in three patients by positron emission tomography (PET), together with continuous inhalation of 15O labeled gases and i.v. injection of [18F]fluoro-2-deoxy-D-glucose. In normal brain, the close local coupling between CBF and CMR-Glc, and that between CMRO2 and CMR-Glc, were well demonstrated. The coupling held for the asymptomatic areas and for parts of the affected hemispheres in two patients with cerebral ischemia. In one patient the CBF/CMR-Glc couple, but not the CMRO2/CMR-Glc couple, was disrupted in the acute ischemic core. This preliminary work demonstrates the local quantification of these important functional parameters, and indicates the potential usefulness of studying their pathophysiological interrelationship in brain disease

213

Rat brain free glucose and lactate measurement by a novel method using bisecting decapitation-extrusion and enzyme denaturation at five seconds.  

Science.gov (United States)

This study investigates a novel method as a means for animal decapitation with rapid brain removal and enzyme denaturation. Briefly, the rat head is simultaneously decapitated and bisected. Either half of the in situ brain is aspirated under -250 mm Hg pressure into a modified small plastic syringe and then extruded through a needle as a fine strand into a relatively large volume of 2 M urea at 95 degrees C. After cooling, sonication, and centrifugation of the brain homogenate, the supernatant is measured enzymatically for brain free glucose and lactate concentration. Enzyme denaturation is effected within 4-6 s. The results are in good agreement with published values for glucose and lactate using other rapid enzyme inactivation techniques. PMID:1988559

Oldendorf, W H; Stoller, B E

1991-02-01

214

Analog and VLSI circuits  

CERN Document Server

Featuring hundreds of illustrations and references, this book provides the information on analog and VLSI circuits. It focuses on analog integrated circuits, presenting the knowledge on monolithic device models, analog circuit cells, high performance analog circuits, RF communication circuits, and PLL circuits.

Chen, Wai-Kai

2009-01-01

215

Dexamethasone increases glucose cycling, but not glucose production, in healthy subjects  

International Nuclear Information System (INIS)

We established that measurement of glucose fluxes through glucose-6-phosphatase (G-6-Pase; hepatic total glucose output, HTGO), glucose cycling (GC), and glucose production (HGP), reveals early diabetogenic changes in liver metabolism. To elucidate the mechanism of the diabetogenic effect of glucocorticoids, we treated eight healthy subjects with oral dexamethasone (DEX; 15 mg over 48 h) and measured HTGO with [2-3H]glucose and HGP with [6-3H]glucose postabsorptively and during a 2-h glucose infusion (11.1 mumol.kg-1.min-1). [2-3H]- minus [6-3H]glucose equals GC. DEX significantly increased plasma glucose, insulin, C peptide, and HTGO, while HGP was unchanged. In controls and DEX, glucose infusion suppressed HTGO (82 vs. 78%) and HGP (87 vs. 91%). DEX increased GC postabsorptively (three-fold) P less than 0.005 and during glucose infusion (P less than 0.05) but decreased metabolic clearance and glucose uptake (Rd), which eventually normalized, however. Because DEX increased HTGO (G-6-Pase) and not HGP (glycogenolysis + gluconeogenesis), we assume that DEX increases HTGO and GC in humans by activating G-6-Pase directly, rather than by expanding the glucose 6-phosphate pool. Hyperglycemia caused by peripheral effects of DEX can also contribute to an increase in GC by activating glucokinase. Therefore, measurement of glucose fluxes through G-6-Pase and GC revealed significant early effects of DEX on hepatic glucose metabolism, which are not yet reflected in HGP

216

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)

217

Michaelis-Menten constraints improved cerebral glucose metabolism and regional lumped constant measurements with [18F]fluorodeoxyglucose  

International Nuclear Information System (INIS)

In the three-compartment model of transfer of native glucose and [18F]fluorodeoxyglucose (FDG) into brain, both transport across the blood-brain barrier and phosphorylation by hexokinase can be described by the Michaelis-Menten equation. This permits the use of fixed transport (tau = K*1/K1) and phosphorylation (psi = k*3/k3) ratios and a common partition volume (Ve = K1/k2) for tracer and glucose. By substituting transfer constants of FDG for those of glucose, using tau and psi, the lumped constant was determined directly by positron tomography. The same constraints also eliminated k*2 and k*3 from the model, thus limiting the parameters to K* [equivalent to K*1k*3/(k*2 + k*3)], K*1, and the cerebral vascular volume (Vo). In six healthy elderly men (aged 61 +/- 5 years), time-activity records of cerebral cortical regions were analyzed with tau = 1.1 and psi = 0.3. The results were compared with those of the conventional FDG method. At 20 min, the goodness of fit by the new equation was as good as that of the conventional method at 45 min. The estimates obtained by the constrained method had stable coefficients of variation. After 20 min, regional differences between the estimates were independent of time, although we observed steady decreases of K* and (k*3). The decrease strongly suggested dephosphorylation of FDG-6-phosphate, particularly after 20 min. All estimates of variables with the constrained method were more accurate than those of the conventional method, including the cerebral glucose metabolic rate itself, as well as physiologically more meaningful, particularly with respect to k*2 and k*3

218

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

219

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

220

Intuitive analog circuit design  

CERN Document Server

Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

Thompson, Marc

2013-01-01

 
 
 
 
221

Isolation of a Mutant of Kluyveromyces marxianus Resistant to Glucose Repression  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 thi...

Moeini Hassan; Vallian Sadeq; Nahvi Iraj; Behzadipour Niloofur

2006-01-01

222

Measurement of lumbar muscle glucose utilization rate can be as useful in estimating skeletal muscle insulin resistance as that of thigh muscle  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Skeletal muscle glucose utilization (SMGU can be accessed by positron emission tomography (PET and18F-FDG to characterize insulin resistance. The quantity of skeletal muscle in the lumbar is sufficient to indicate that SMGU in the lumbar (SMGU- lumbar can be measured with18F-FDG PET of the chest instead of obtaining thigh muscle SMGU (SMGU-thigh. This would reduce PET scan time to avoid thigh muscle PET scan. This study was aimed to compare SMGU-lumbar and thigh muscle SMGU under insulin clamping to identify the validity of measurements of SMGU in the lumbar for studies of insulin resistance. Methods: Thirty-three patients underwent sequential dynamic18F-FDG PET of both the thoracic (37 min and thigh region (22 min during hyperinsulinemic euglycemic insulin clamping. Both SMGU-lumbar and SMGU-thigh were calculated by Patlak graphical analysis. Whole body insulin resistance was assessed by a whole body glucose disposal rate during hyperinsulinemic euglycemic insulin clamping. Input function was obtained from the time activity curve of the descending aorta and venous blood sampling as previously validated. Results: SMGU-thigh (0.0506 ± 0.0334 ?mol/min/g was comparable to SMGU-lumbar (0.0497 ± 0.0255 ?mol/min/g. The Bland-Altman method of difference plot analysis showed a significant correlationship between SMGU- thigh and SMGU-lumbar (r = 0.506, p = 0.0028. There were seen very good significant correlationship between whole body glucose utilization rate in both thigh (r = 0.737, p = 0.0001 and lumbar (r = 0.772, p = 0.0001. Conclusion: These results support the validity of measuring SMGU-lumbar to estimate insulin resistance during PET imaging of the chest.

Ikuo Yokoyama

2013-02-01

223

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 (?13CO2oscillator 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. 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

224

Simultaneous measurement of local glucose utilization and blood flow in the rat brain: an autoradiographic method using two tracers labeled with carbon-14  

International Nuclear Information System (INIS)

A simplified technique that uses two radionuclide tracers has been devised to measure local cerebral glucose utilization (ICGU) and local cerebral blood flow (ICBF) in the same rat. The method employs [14C]-2-deoxyglucose and [14C]iodoantipyrine to produce an autoradiogram before and another after extraction into chloroform of the [14C]iodoantipyrine from the brain sections. The chloroform-extracted autoradiogram yields ICGU, and the difference in tissue carbon-14 concentration between the two autoradiograms permits calculation of ICBF. The double-isotope technique provides values of ICGU and ICBF that are statistically indistinguishable from those derived from conventional single-isotope methods

225

Simultaneous measurement of local glucose utilization and blood flow in the rat brain: an autoradiographic method using two tracers labeled with 14C  

International Nuclear Information System (INIS)

A simplified technique that uses two radionuclide tracers has been devised to measure local cerebral glucose utilization (ICGU) and local cerebral blood flow (ICBF) in the same rat. The method employs [14C]-2-deoxyglucose and [14C]iodoantipyrine to produce an autoradiogram before and another after extraction into chloroform of the [14C]iodoantipyrine from the brain sections. The chloroform-extracted autoradiogram yields ICGU, and the difference in tissue 14C concentration between the two autoradiograms permits calculation of ICBF. The double-isotope technique provides values of ICGU and ICBF that are statistically indistinguishable from those derived from conventional single-isotope methods

226

A low-cost solution to measure mouse licking in an electrophysiological setup with a standard analog-to-digital converter.  

Science.gov (United States)

Licking behavior in rodents is widely used to determine fluid consumption in various behavioral contexts and is a typical example of rhythmic movement controlled by internal pattern-generating mechanisms. The measurement of licking behavior by commercially available instruments is based on either tongue protrusion interrupting a light beam or on an electrical signal generated by the tongue touching a metal spout. We report here that licking behavior can be measured with high temporal precision by simply connecting a metal sipper tube to the input of a standard analog/digital (A/D) converter and connecting the animal to ground (via a metal cage floor). The signal produced by a single lick consists of a 100-800 mV dc voltage step, which reflects the metal-to-water junction potential and persists for the duration of the tongue-spout contact. This method does not produce any significant electrical artifacts and can be combined with electrophysiological measurements of single unit activity from neurons involved in the control of the licking behavior. PMID:16364450

Hayar, Abdallah; Bryant, Jeri L; Boughter, John D; Heck, Detlef H

2006-06-15

227

Sucrose, glucose, and fructose extraction in aqueous carrot root extracts prepared at different temperatures by means of direct NMR measurements.  

Science.gov (United States)

Solutions obtained by heating carrot roots in water (stocks) are widely used in the food industry, but little information is available regarding the metabolites (intermediates and products of metabolism) found in the stock. The effect of treatment temperature and duration on the sugar composition of stocks was investigated directly by quantitative (1)H NMR spectroscopy, to understand the extraction mechanism when processing at 100 degrees C. Stocks prepared at three different temperatures (50, 75, and 100 degrees C) were investigated for up to 36 h. Three sugars (sucrose, glucose, and fructose) were detected and quantified. The concentrations of these three sugars reached a maximum after 9 h when the temperature of treatment was 50 or 75 degrees C. At 100 degrees C, the sucrose concentration reached a maximum after 3 h, whereas the concentration of glucose and fructose was still increasing at that time. Comparison of the kinetic composition of these carrot stocks with that of model sugar solutions leads to the proposal that the changes in stock composition result from sugar diffusion, sucrose hydrolysis, and hydroxymethylfurfural (HMF) formation. PMID:16787015

Cazor, Anne; Deborde, Catherine; Moing, Annick; Rolin, Dominique; This, Hervé

2006-06-28

228

Enhancing the characterization of bedload transport in rivers using the analogy between the Hertz contact theory and plate hydrophone measurements  

Science.gov (United States)

Vibration measurements performed with plate or pipe geophone/hydrophone systems are of growing interest for bedload transport monitoring since they allow performing high temporal resolution and continuous records. Our set-up is constituted by a piezoelectric hydrophone acting as a "sediment vibration sensor" in contact with a steel plate located on the streambed. With such an apparatus, the signal processing is generally reduced to power spectral analysis or impact counting. However, a large amount of useful information is contained in the waveform of the impact signal, which conveys the force and the contact time that the bedload imposes on the plate. The wave amplitude is not well constrained because it varies a lot with changing impact location and velocity. The wave frequency is a more relevant parameter, less sensitive to these variables. According to the Hertz contact theory the frequency of the first signal arrival (flexural wave) is directly proportional to the bed-material grain size. Then, an appropriate analysis of the frequency attributes (central frequency, modulation) is needed to estimate the size of bedload particles. In this way, we have developed a complete processing algorithm based on a high dimensional decomposition method (chirplet transform) to get an accurate estimation of the first arrival frequency content. Results on summer flood events in a lowland river show that impacts are well separated by their central frequency and that most of transport occurs during larger peak flows. The portion of coarser sediment which is characterized by low frequencies is preferentially transported during the rising limb whereas the finer sand fraction identified by higher frequencies is transported during both rising and falling limb. Such a processing offers the opportunity to better understand the bedload signature of vibration measurements and is promising in view of quantifying processes of bedload transport and deposition. This final objective of quantification is an ongoing research by performing a flume experiment with various impact velocity and granulometry (collaboration with the Hydrology Department of Trier University).

Barrière, Julien; Oth, Adrien; Schenkluhn, Reimar; Krein, Andreas

2014-05-01

229

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

230

Glucose sensing by means of silicon photonics  

Science.gov (United States)

Diabetes is a fast growing metabolic disease, where the patients suffer from disordered glucose blood levels. Monitoring the blood glucose values in combination with extra insulin injection is currently the only therapy to keep the glucose concentration in diabetic patients under control, minimizing the long-term effects of elevated glucose concentrations and improving quality of life of the diabetic patients. Implantable sensors allow continuous glucose monitoring, offering the most reliable data to control the glucose levels. Infrared absorption spectrometers offer a non-chemical measurement method to determine the small glucose concentrations in blood serum. In this work, a spectrometer platform based on silicon photonics is presented, allowing the realization of very small glucose sensors suitable for building implantable sensors. A proof-of-concept of a spectrometer with integrated evanescent sample interface is presented, and the route towards a fully implantable spectrometer is discussed.

Bockstaele, Ronny; Ryckeboer, Eva; Hattasan, Nannicha; De Koninck, Yannick; Muneeb, Muhammad; Verstuyft, Steven; Delbeke, Danaë; Bogaerts, Wim; Roelkens, Gunther; Baets, Roel

2014-03-01

231

Microwave-Based Biosensor for Glucose Detection  

Science.gov (United States)

In this project, microwave-based biosensor for glucose detection has been studied. The study is based on the dielectric properties changes at microwave frequency for glucose-enzyme reaction. Glucose interaction with glucose oxidase (GOD) produced gluconic acid and hydrogen peroxide. The reaction of the glucose solutions with an enzyme was carried out in 1:3 of glucose and enzyme respectively. The measurements were done using the Open Ended Coaxial Probe (OECP) coupled with computer controlled software automated network analyzer (ANA) with frequency range from 200MHz to 20GHz at room temperature (25 °C). The differences of enzyme and glucose-enzyme reaction were calculated and plotted. In the microwave interaction with the glucose-enzyme reaction, ionic conduction and dipole molecules was detected at 0.99GHz and 16.44GHz respectively based on changes of dielectric loss factor.

Salim, N. S. M.; Khalid, K.; Yusof, N. A.

2010-07-01

232

Effects of 5 Thio-D-Glucose on cellular adenosine triphosphate levels and deoxyribonucleic acid rejoining in hypoxic and aerobic Chinese hamster cells  

International Nuclear Information System (INIS)

Intracellular adenosine triphosphate (ATP) levels were measured in both hypoxic and aerobic cultures of V79 Chinese hamster cells treated with 5-thio-D-glucose (5-SH-D-Glc). This glucose analog, a known inhibitor of D-glucose transport and metabolism, reduced ATP in cell cultures allowed to become hypoxic by cell metabolism, but not in aerobic cultures treated similarly. Cells depleted of ATP were unable to rejoin x-ray induced deoxyribonucleic acid (DNA) strand breaks as measured by the alkaline sucrose gradient sedimentation technique. The inference for radiation therapy is that inhibition of glucose metabolism selectively depletes energy reserves in hypoxic cells, rendering these cells more radiosensitive and leading to a more effective tumor treatment

233

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

234

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

235

Defining a minimal clinically important difference for endometriosis-associated pelvic pain measured on a visual analog scale: analyses of two placebo-controlled, randomized trials  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background When comparing active treatments, a non-inferiority (or one-sided equivalence study design is often used. This design requires the definition of a non-inferiority margin, the threshold value of clinical relevance. In recent studies, a non-inferiority margin of 15 mm has been used for the change in endometriosis-associated pelvic pain (EAPP on a visual analog scale (VAS. However, this value was derived from other chronic painful conditions and its validation in EAPP was lacking. Methods Data were analyzed from two placebo-controlled studies of active treatments in endometriosis, including 281 patients with laparoscopically-confirmed endometriosis and moderate-to-severe EAPP. Patients recorded EAPP on a VAS at baseline and the end of treatment. Patients also assessed their satisfaction with treatment on a modified Clinical Global Impression scale. Changes in VAS score were compared with patients' self-assessments to derive an empirically validated non-inferiority margin. This anchor-based value was compared to a non-inferiority margin derived using the conventional half standard deviation rule for minimal clinically important difference (MCID in patient-reported outcomes. Results Anchor-based and distribution-based MCIDs were-7.8 mm and-8.6 mm, respectively. Conclusions An empirically validated non-inferiority margin of 10 mm for EAPP measured on a VAS is appropriate to compare treatments in endometriosis.

Schmitz Heinz

2010-11-01

236

Evaluation and clinically relevant applications of a fluorescent imaging analog to fluorodeoxyglucose positron emission tomography  

Science.gov (United States)

A fluorescent analog to 2-deoxy-2 [18F] fluoro-D-glucose position emission tomography (FDG-PET) would allow for the introduction of metabolic imaging into intraoperative and minimally invasive settings. We present through in vitro and in vivo experimentation an evaluation of 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), a fluorescently labeled glucose molecule, as a molecular beacon of glucose utilization. The competitive inhibition of 2-NBDG uptake by excess free glucose is directly compared against FDG uptake inhibition in cultured cells. 2-NBDG uptake in the brain of a mouse experiencing a generalized seizure is measured, as well as in subcutaneously implanted tumors in mice during fed and fasting states. Localization of 2-NBDG into malignant tissues is studied by laser scanning microscopy. The clinical relevance of 2-NBDG imaging is examined by performing fluorescence colonoscopy, and by correlating preoperative FDG-PET with intraoperative fluorescence imaging. 2-NBDG exhibits a similar uptake inhibition to FDG by excess glucose in the growth media. Uptake is significantly increased in the brain of an animal experiencing seizures versus control, and in subcutaneous tumors after the animals are kept nil per os (NPO) for 24 h versus ad libidum feeding. The clinical utility of 2-NBDG is confirmed by the demonstration of very high target-to-background ratios in minimally invasive and intraoperative imaging of malignant lesions. We present an optical analog of FDG-PET to extend the applicability of metabolic imaging to minimally invasive and intraoperative settings.

Sheth, Rahul A.; Josephson, Lee; Mahmood, Umar

2009-11-01

237

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 ...

238

Gravito-electromagnetic analogies  

CERN Document Server

We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors, and the related issue of super-energy, are also discussed, and the physical insight from the tidal tensor formalism is seen to yield a suggestive interpretation of the phenomenon of gravitational ra...

Costa, L Filipe O

2012-01-01

239

Classical analog of entanglement  

International Nuclear Information System (INIS)

We show that quantum entanglement has a very close classical analog, namely, secret classical correlations. The fundamental analogy stems from the behavior of quantum entanglement under local operations and classical communication and the behavior of secret correlations under local operations and public communication. A large number of derived analogies follow. In particular, teleportation is analogous to the one time pad, the concept of 'pure state' exists in the classical domain, entanglement concentration and dilution are essentially classical secrecy protocols, and single-copy-entanglement manipulations have such a close classical analog that the majorization results are reproduced in the classical setting. This analogy allows one to import questions from the quantum domain into the classical one, and vice versa, helping to get a better understanding of both. Also, by identifying classical aspects of quantum entanglement, it allows one to identify those aspects of entanglement that are uniquely quantum mechanical

240

Classical analog of entanglement  

Science.gov (United States)

We show that quantum entanglement has a very close classical analog, namely, secret classical correlations. The fundamental analogy stems from the behavior of quantum entanglement under local operations and classical communication and the behavior of secret correlations under local operations and public communication. A large number of derived analogies follow. In particular, teleportation is analogous to the one time pad, the concept of ``pure state'' exists in the classical domain, entanglement concentration and dilution are essentially classical secrecy protocols, and single-copy-entanglement manipulations have such a close classical analog that the majorization results are reproduced in the classical setting. This analogy allows one to import questions from the quantum domain into the classical one, and vice versa, helping to get a better understanding of both. Also, by identifying classical aspects of quantum entanglement, it allows one to identify those aspects of entanglement that are uniquely quantum mechanical.

Collins, Daniel; Popescu, Sandu

2002-03-01

 
 
 
 
241

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

242

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

243

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

Energy Technology Data Exchange (ETDEWEB)

Two iodinated acetals of D-glucose, 4,6-(R)-O-(2'-iodoethylidene)-{alpha}, {beta}-D-glucose and 4,6-(R)-O-(4'-iodobenzylidene)-{alpha}, {beta}-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.

Brunet-Desruet, Marie-Dominique; Ghezzi, Catherine; Morin, Christophe; Comet, Michel; Fagret, Daniel

1998-07-01

244

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

245

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

246

Laboratory measurements of P-wave and S-wave velocities across a surface analog of the continental crust-mantle boundary: Cabo Ortegal, Spain  

Science.gov (United States)

The Paleozoic Cabo Ortegal Complex of NW Spain provides an exposed analog of the continental crust-mantle transition. It is composed of an overturned section that, at its base, begins with felsic gneisses, followed upward by eclogites, intermediate and mafic granulties, and ultramafic rocks. Peak metamorphic conditions reached c. 800°C and 1.7 GPa in the Middle to Late Devonian. Fourteen samples were analysed for P-wave and S-wave velocities, as well as density at the High Pressure Lab at Dalhousie University, Canada. Seismic velocities were measured at pressures of 10 to 600 MPa at a temperature of 20°C. When possible, measurements were made parallel and perpendicular to banding and parallel to the lineation. The major element composition of each sample was measured by XRF at the University of Barcelona, Spain. Samples display a broad range of P-wave and S-wave velocities (6.2 to 8.2 km/s and 3.2 to 4.6 km/s at 600 MPa, respectively) that generally increase with density (2.7 to 3.4 g/cm3) and reflect an overall increase from middle to lower crustal velocities in the felsic gneisses and intermediate to mafic granulites to mantle velocities in the eclogites and ultramafic rocks. The seismic Moho (P-wave velocity > 7.6 km/s) is reached at the mappable contact between the gneisses and the eclogite, whereas the compositional Moho, or crust-mantle transition occurs at the transitional contact between the mafic granulites and peridotites. Between 200 and 600 MPa, P-wave anisotropy ranges from between 2% and 8%, whereas S-wave anisotropy ranges from <1% to around 8%, according to rock type. Poisson's ratios calculated from the laboratory measurements are within the range of those determined from field experiments elsewhere. P-wave reflection coefficients between the various lithologies range from 0.21 to 0.08. These laboratory data provide a calibration for the physical properties and the nature of reflectivity of the in-situ lower continental crust and upper mantle transition.

Brown, Dennis; Llana-Funez, Sergio; Carbonell, Ramon; Alvarez-Marron, Joaquina; Marti, David; Salisbury, Matt

2010-05-01

247

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

International Nuclear Information System (INIS)

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)

248

Underestimation of hepatic glucose production by radioactive and stable tracers  

International Nuclear Information System (INIS)

Although negative hepatic glucose production rates are physiologically impossible, they have been observed when hepatic glucose production is measured with the tracer-dilution technique during the hyperinsulinemic, euglycemic glucose clamp. Because hepatic glucose production is determined from the difference between tracer-derived glucose disposal and the known exogenous glucose infusion rate, the negative values for hepatic glucose production must result from an underestimation of glucose disposal by the tracer technique. In the current investigation, tracer-derived glucose disposal was measured in 25 subjects undergoing hyperinsulinemic, euglycemic clamps. Glucose disposal was measured with both radioactive and stable isotopes that utilize different methodologies, to determine whether discriminant metabolism of the isotopes versus methodological error leads to underestimation of tracer-derived glucose disposal. Both the radioactive and stable methodologies underestimated the exogenous glucose infusion rate during the hyperinsulinemic euglycemic clamp by 27 and 17%, respectively. Mean hepatic glucose production was -2.1 +/- 0.2 and -1.3 +/- 0.2 mg X kg-1 X min-1 as determined by the radioactive and stable isotope methodologies, respectively. Methodological error was an unlikely cause of this underestimation because it occurred with two different methodologies. The most likely explanation for underestimated rates of glucose disposal determined by the two types of isotope methodologies is discrepant metabolism of glucose tracers in comparison with unlabeled glucose

249

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

DEFF Research Database (Denmark)

OBJECTIVEWe studied whether patterns of glucose absorption during oral glucose tolerance tests (OGTTs) were abnormal in individuals with impaired glucose regulation and whether they were related to sex and body size (height and fat-free mass). We also examined how well differences in insulin sensitivity and -cell function measured by gold-standard tests were reflected in the corresponding OGTT-derived estimates.RESEARCH DESIGN AND METHODSWith validated methods, various aspects of glucose absorption were estimated from 12-point, 3-h, 75-g OGTTs in 66 individuals with normal glucose tolerance (NGT), isolated impaired fasting glucose (i-IFG), or isolated impaired glucose tolerance (i-IGT). Insulin sensitivity and -cell function were measured with the euglycemic-hyperinsulinemic clamp and intravenous glucose tolerance tests, respectively. Surrogate markers of both conditions were calculated from OGTTs.RESULTSMore rapid glucose absorption (P 0.036) and reduced late glucose absorption (P 0.039) were observed in thei-IFG group relative to NGT and i-IGT groups. Women with i-IGT had a lower early glucose absorption than did men with i-IGT (P = 0.041); however, this difference did not persist when differences in body size were taken into account (P > 0.28). Faster glucose absorption was related to higher fasting (P = 0.001) and lower 2-h (P = 0.001) glucose levels and to greater height and fat-free mass (P <0.001). All OGTT-derived measures of insulin sensitivity, but only one of three measures of -cell function, reflected the differences for these parameters between those with normal and impaired glucose regulation as measured by gold-standard tests.CONCLUSIONSGlucose absorption patterns during an OGTT are significantly related to plasma glucose levels and body size, which should be taken into account when estimating -cell function from OGTTs in epidemiological studies.

Hansen, Torben

2013-01-01

250

Challenges in Using Analogies  

Science.gov (United States)

Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same…

Lin, Shih-Yin; Singh, Chandralekha

2011-01-01

251

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

252

Analog optical intersatellite links  

Science.gov (United States)

We have adopted the phase modulation technique from the digital Syncbit communication system, and developed an analog transmission system which allows to transmit a set of analog channels between standard bent - pipe satellites. This new analog coherent modulation communication system provides excellent receiver sensitivity which in turn allows to keep the optical output power of the transmitter to a minimum. As a result power consumption from the host spacecraft -- a valuable resource -- can be kept to a minimum. The analog communication system design is such, that it uses all the electro-optical building blocks of the digital communication system. Transmitter laser, modulator, booster amplifier and optical receiver frontend are nearly identical for the analog and the digital terminals. The subsystem is contained in two standard electronics module frames and fits into the modular electronics unit of the terminal.

Pribil, Klaus; Kudielka, Klaus H.

2002-04-01

253

Glucose metabolism in diabetic blood vessels  

International Nuclear Information System (INIS)

Since glycolysis appears to be coupled to active ion transport in vascular smooth muscle, alterations in glucose metabolism may contribute to cellular dysfunction and angiopathy in diabetes. Uptake and utilization of glucose were studied in perfused blood vessels in which pulsatile flow and perfusion pressure were similar to those measured directly in vivo. Thoracic aortae isolated from 8-wk alloxan diabetic (D) and nondiabetic control rabbits were cannulated, tethered, and perfused with oxygenated buffer containing 7 or 25 mM glucose and tracer amounts of glucose-U-14 C. Norepinephrine (NE) (10-6 M) and/or insulin (I) (150 ?U/ml) and albumin (0.2%) were added. NE-induced tension development increased glucose uptake 39% and 14CO2 and lactate production 2.3-fold. With 7 mM glucose, marked decreases in glucose uptake (74%), 14CO2 (68%), lactate (30%), total tissue glycogen (75%), and tissue phospholipids (70%) were observed in D. Addition of I or elevation of exogenous glucose to 25 mM normalized glucose uptake, but had differential effects on the pattern of substrate utilization. Thus, in D, there was a marked depression of vascular glucose metabolism that was partially reversed by addition of low concentrations of insulin or D levels of glucose

254

Glucose intolerance: the hidden danger in hypertensives!  

Science.gov (United States)

Both systemic hypertension and abnormalities of glucose metabolism are independent recognised risk factors for the development of cardiovascular morbidity and mortality, but their effects become additive when they coexist. Hypertension and glucose intolerance increase arterial stiffness and lead to cardiac structural and functional changes such as left ventricular hypertrophy and diastolic dysfunction of the left ventricle. Oral glucose tolerance tests have shown that 58% of patients with systemic hypertension who have no cardiac history and who are not known to have diabetes, suffer from unrecognised abnormalities of glucose metabolism i.e. either diabetes or impaired glucose tolerance. Using the fasting plasma glucose level and/or glycated haemoglobin concentration to diagnose glucose intolerance in patients with systemic hypertension is insufficient because of their low sensitivity for the diagnosis of diabetes and their inability to identify impaired glucose tolerance. It is important to recognise abnormalities of glucose metabolism early in patients with systemic hypertension in order to implement appropriate management and avoid further complications. Failure to identify glucose intolerance results in serious underestimation of the cardiovascular risk of these patients and denies patients primary preventative measures, which are based on risk assessment. All patients referred to Hypertension Clinics for the management of raised blood pressure should therefore be investigated by glucose tolerance test. PMID:16158028

Salmasi, A M; Dancy, M

2005-09-01

255

Accuracy of different methods for blood glucose measurement in critically ill patients / Acurácia de diferentes métodos para mensuração de glicemia em pacientes graves  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese CONTEXTO E OBJETIVO: Apesar de glicosímetros não serem validados para unidades de terapia intensiva (UTI), seu uso é corriqueiro. O objetivo foi avaliar a acurácia e concordância clínica entre a glicemia arterial por colorimetria (glicA-lab), glicemias capilar (glicC-fita) e arterial (glicA-fita) po [...] r glicosimetria, e venosa central por colorimetria (glicV-lab). TIPO DE ESTUDO E LOCAL: Estudo transversal realizado em hospital universitário. MÉTODO: Foram incluídos 40 pacientes com choque séptico e indivíduos estáveis, sem infecção. A correlação entre medidas foi avaliada tanto na amostra global quanto nos subgrupos em uso de noradrenalina e com sinais de hipoperfusão tecidual. RESULTADOS: A glicC-fita mostrou pior correlação (r = 0,8289) e concordância (-9,87 ± 31,76). Esta superou os limites aceitáveis de variação do Clinical and Laboratory Standards Institute em 23,7% dos casos, sendo maior que a glicA-lab em 90% das vezes. A glicA-fita teve a melhor correlação (r = 0,9406), com concordância de -6,75 ± 19,07 e variação significativa em 7,9%. Para a glicV-lab, obteve-se r = 0,8549, concordância de -4,20 ± 28,37 e variação significativa em 15,7%. Variação significativa foi mais frequente em pacientes com noradrenalina (36,4% versus 6,3%, P = 0,03), mas não nos com hipoperfusão. Houve discordância de conduta clínica em 25%, 22,5% e 15% dos casos para glicC-fita, glicV-lab e glicA-fita, respectivamente. CONCLUSÃO: O uso de glicC-fita deveria ser evitado, principalmente se há uso de noradrenalina. Geralmente, este método superestima a glicemia real e acarreta erros de conduta. REGISTRO DO ENSAIO CLÍNICO: ACTRN12608000513314 (registrado como estudo observacional transversal). Abstract in english CONTEXT AND OBJECTIVE: Although glucometers have not been validated for intensive care units, they are regularly used. The aim of this study was to compare and assess the accuracy and clinical agreement of arterial glucose concentration obtained using colorimetry (Agluc-lab), capillary (Cgluc-strip) [...] and arterial (Agluc-strip) glucose concentration obtained using glucometry and central venous glucose concentration obtained using colorimetry (Vgluc-lab). DESIGN AND SETTING: Cross-sectional study in a university hospital. METHOD: Forty patients with septic shock and stable individuals without infection were included. The correlations between measurements were assessed both in the full sample and in subgroups using noradrenalin and presenting signs of tissue hypoperfusion. RESULTS: Cgluc-strip showed the poorest correlation (r = 0.8289) and agreement (-9.87 ± 31.76). It exceeded the limits of acceptable variation of the Clinical and Laboratory Standards Institute in 23.7% of the cases, and was higher than Agluc-lab in 90% of the measurements. Agluc-strip showed the best correlation (r = 0.9406), with agreement of -6.75 ± 19.07 and significant variation in 7.9%. For Vgluc-lab, r = 0.8549, with agreement of -4.20 ± 28.37 and significant variation in 15.7%. Significant variation was more frequent in patients on noradrenalin (36.4% versus 6.3%; P = 0.03) but not in the subgroup with hypoperfusion. There was discordance regarding clinical management in 25%, 22% and 15% of the cases for Cgluc-strip, Vgluc-lab and Agluc-strip, respectively. CONCLUSION: Cgluc-strip should be avoided, particularly if noradrenalin is being used. This method usually overestimates the true glucose levels and gives rise to management errors. CLINICAL TRIAL REGISTRATION: ACTRN12608000513314 (registered as an observational, cross-sectional study).

Sérgio Antônio, Pulzi Júnior; Murillo Santucci Cesar de, Assunção; Bruno Franco, Mazza; Haggéas da Silveira, Fernandes; Mirian, Jackiu; Flávio Geraldo Resende, Freitas; Flávia Ribeiro, Machado.

256

Accuracy of different methods for blood glucose measurement in critically ill patients / Acurácia de diferentes métodos para mensuração de glicemia em pacientes graves  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese CONTEXTO E OBJETIVO: Apesar de glicosímetros não serem validados para unidades de terapia intensiva (UTI), seu uso é corriqueiro. O objetivo foi avaliar a acurácia e concordância clínica entre a glicemia arterial por colorimetria (glicA-lab), glicemias capilar (glicC-fita) e arterial (glicA-fita) po [...] r glicosimetria, e venosa central por colorimetria (glicV-lab). TIPO DE ESTUDO E LOCAL: Estudo transversal realizado em hospital universitário. MÉTODO: Foram incluídos 40 pacientes com choque séptico e indivíduos estáveis, sem infecção. A correlação entre medidas foi avaliada tanto na amostra global quanto nos subgrupos em uso de noradrenalina e com sinais de hipoperfusão tecidual. RESULTADOS: A glicC-fita mostrou pior correlação (r = 0,8289) e concordância (-9,87 ± 31,76). Esta superou os limites aceitáveis de variação do Clinical and Laboratory Standards Institute em 23,7% dos casos, sendo maior que a glicA-lab em 90% das vezes. A glicA-fita teve a melhor correlação (r = 0,9406), com concordância de -6,75 ± 19,07 e variação significativa em 7,9%. Para a glicV-lab, obteve-se r = 0,8549, concordância de -4,20 ± 28,37 e variação significativa em 15,7%. Variação significativa foi mais frequente em pacientes com noradrenalina (36,4% versus 6,3%, P = 0,03), mas não nos com hipoperfusão. Houve discordância de conduta clínica em 25%, 22,5% e 15% dos casos para glicC-fita, glicV-lab e glicA-fita, respectivamente. CONCLUSÃO: O uso de glicC-fita deveria ser evitado, principalmente se há uso de noradrenalina. Geralmente, este método superestima a glicemia real e acarreta erros de conduta. REGISTRO DO ENSAIO CLÍNICO: ACTRN12608000513314 (registrado como estudo observacional transversal). Abstract in english CONTEXT AND OBJECTIVE: Although glucometers have not been validated for intensive care units, they are regularly used. The aim of this study was to compare and assess the accuracy and clinical agreement of arterial glucose concentration obtained using colorimetry (Agluc-lab), capillary (Cgluc-strip) [...] and arterial (Agluc-strip) glucose concentration obtained using glucometry and central venous glucose concentration obtained using colorimetry (Vgluc-lab). DESIGN AND SETTING: Cross-sectional study in a university hospital. METHOD: Forty patients with septic shock and stable individuals without infection were included. The correlations between measurements were assessed both in the full sample and in subgroups using noradrenalin and presenting signs of tissue hypoperfusion. RESULTS: Cgluc-strip showed the poorest correlation (r = 0.8289) and agreement (-9.87 ± 31.76). It exceeded the limits of acceptable variation of the Clinical and Laboratory Standards Institute in 23.7% of the cases, and was higher than Agluc-lab in 90% of the measurements. Agluc-strip showed the best correlation (r = 0.9406), with agreement of -6.75 ± 19.07 and significant variation in 7.9%. For Vgluc-lab, r = 0.8549, with agreement of -4.20 ± 28.37 and significant variation in 15.7%. Significant variation was more frequent in patients on noradrenalin (36.4% versus 6.3%; P = 0.03) but not in the subgroup with hypoperfusion. There was discordance regarding clinical management in 25%, 22% and 15% of the cases for Cgluc-strip, Vgluc-lab and Agluc-strip, respectively. CONCLUSION: Cgluc-strip should be avoided, particularly if noradrenalin is being used. This method usually overestimates the true glucose levels and gives rise to management errors. CLINICAL TRIAL REGISTRATION: ACTRN12608000513314 (registered as an observational, cross-sectional study).

Sérgio Antônio, Pulzi Júnior; Murillo Santucci Cesar de, Assunção; Bruno Franco, Mazza; Haggéas da Silveira, Fernandes; Mirian, Jackiu; Flávio Geraldo Resende, Freitas; Flávia Ribeiro, Machado.

2009-09-01

257

Glucose reabsorption from bile. Evidence for a biliohepatic circulation.  

Science.gov (United States)

Glucose is absent from human bile and present in low concentrations in bile from the rat. To study the mechanisms of this blood-bile glucose concentration difference, infusions of glucose were administered i.v. to 300-400 g male Sprague-Dawley rats with ligated renal pedicles and to two postcholecystectomy patients with indwelling t-tubes. Glucose was assayed in plasma, bile, and rat liver by a hexokinase method specific for D-glucose. In man, glucose was detected in bile when plasma glucose increased above 350 mg/100 ml. In animals studies, low concentrations of bile glucose were observed at plasma levels between 100 and 300 mg/100 ml. However, when plasma concentrations increased between 400 and 900 mg/100 ml, glucose appeared more rapidly in bile, defining by extrapolation an apparent plasma glucose threshold of 280 mg/100 ml. Intraportal phlorizin, a competitive inhibitor of glucose transport, significantly increased bile glucose concentrations. Plasma-bile concentration differences were also observed in rats after i.v. [3-14C]O-methyl glucose (3-O-MG) but not after [3H]mannitol. Hepatic glucose levels were never lower than plasma levels and liver-plasma 3-O-MG ratios were 0.92 +/- 0.22 indicating that entry of glucose and 3-O-MG into hepatocyte water was not limiting. Furthermore, when sodium dehydrocholate augmented canalicular secretion, biliary glucose excretion increased proportionally suggesting that glucose entry into bile was not impeded. When estimates of hepatic glucose secretion were compared with biliary glucose excretion, the latter increased progressively when estimated secretion rates exceeded 50 micrograms/min or when phlorizin was given. Finally, during bile stop-flow experiments, [3-14C]O-MG and [14C]glucose were selectively removed from bile compared with [3H]mannitol. The findings suggest that glucose and 3-O-MG are reabsorbed from bile after entry at the hepatocyte, accounting for their low bile-plasma ratio. The biliary glucose transport process may be described by Michaelis-Menten kinetics and is analogous to recently defined kinetics for renal tubular reabsorption of glucose. These studies provide evidence that certain products of bile secretion may undergo a "biliohepatic" circulation. PMID:11344566

Guzelian, P; Boyer, J L

1974-01-01

258

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

259

Discrete LIBOR Market Model Analogy  

CERN Document Server

This paper provides a discrete time LIBOR analog, which can be used for arbitrage-free discretization of Levy LIBOR models or discrete approximation of continuous time LIBOR market models. Using the work of Eberlein and Oezkan as an inspiration, we build a discrete forward LIBOR market model by starting with a discrete exponential martingale. We take this pure jump process and calculate the appropriate measure change between the forward measures. Next we prove weak convergence of the discrete analog to the continuous time LIBOR model, provided the driving process converges weakly to the continuous time one and the driving processes are PII's. This especially implies the weak convergence of the model to a Levy LIBOR market model if the driving process variables are infinitely divisible distributions. This also relates our model to an Euler discretization.

Hula, Andreas

2011-01-01

260

The BIGTT test : a novel test for simultaneous measurement of pancreatic beta-cell function, insulin sensitivity, and glucose tolerance  

DEFF Research Database (Denmark)

Insulin resistance and impaired beta-cell function are key elements in the pathogenesis of type 2 diabetes. We aimed to develop valid algorithms for estimation of the insulin sensitivity index (S(I)) and acute insulin response (AIR) derived from simple and cheap physiological measurements that could be used in large-scale metabolic, genetic, and epidemiological studies.

Hansen, Torben; Drivsholm, Thomas

2007-01-01

 
 
 
 
261

The Impact of Melatonin on Glucose Homeostasis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective: Melatonin is a pineal product mainly charged with the maintenance of antioxidant conditions in human. This study is performed to identify the short-term effect of melatonin on glucose homeostasis in diabetic patients. Materials and Methods: Melatonin and placebo were given perorally to sixty patients. Blood glucose and insulin levels were measured with constant intervals. Results: No significant correlation was found among the levels of glucose, insulin and HOMA-IR index at any ti...

Zeynep Arzu Ye?in; Rüya Mutluay; ?ehri Elbeg; Resul Karaku?; Nuri Çak?r

2009-01-01

262

Immobilized glucose oxidase in the potentiometric detection of glucose.  

Science.gov (United States)

Previous work has shown that glucose oxidase can be immobilized on platinum to give an electrode that responds potentiometrically to glucose over the clinically useful range of about 10-250 mg glucose/100 mL. The present studies were carried out with electrochemically pretreated platinum and with gold or porous graphite substituted for the platinum support. The presence of the enzyme gave a significantly enhanced potentiometric response over that obtained with the bare support for both the pretreated platinum and the porous graphite, but not with gold. However, with platinum the potentiometric response became more negative with increasing glucose concentration. With porous graphite, the potential changed in the positive direction as the glucose concentration was increased. Hysteresis was demonstrated for the platinum-enzyme electrode. Mass transfer measurements with a rotating ring-disc electrode (RRDE) showed measurable diffusional resistances to the transport of a model electroactive compound (potassium ferrocyanide) through a matrix of immobilized enzyme attached to the disc of the RRDE. These results are part of a larger study to define the source of the potentiometric response by examining the roles of the support and the mass transfer resistances through the immobilized enzyme matrix. PMID:6476822

Wingard, L B; Castner, J F; Yao, S J; Wolfson, S K; Drash, A L; Liu, C C

1984-02-01

263

Cerebral muscarinic acetylcholinergic receptor measurement in Alzheimer's disease patients on 11C-N-methyl-4-piperidyl benzilate. Comparison with cerebral blood flow and cerebral glucose metabolism  

International Nuclear Information System (INIS)

We studied the cerebral muscarinic acetylcholinergic receptor (mACh-R) by means of 11C-N-methyl-4-piperidyl benzilate (11C-NMPB) and positron emission tomography (PET) in Alzheimer''s disease (AD) cases, and the findings were compared with the cerebral blood flow (CBF) and the glucose metabolism (CMRGlc) to evaluate the relationship between the mACh-R and the CBF or the CMRGlc. The subjects consisted of 18 patients with AD and 18 age and sex matched normal volunteers. The patients were clinically diagnosed according to the criteria of the NINDS-ADRDA as having ''''probable AD'''' and were thus classified into two groups (mild and moderate AD) according to the severity of dementia determined by DSM-III-R. The CBF was measured by 99mTc-HMPAO SPECT, and the CMRGlc was measured by 18FDG PET. The 11C-NMPB uptake was evaluated by the graphical method and the ratio method (ROIs/Cerebellum). A significant mACh-R decrease and more severe CMRGlc decrease in the cortical region was seen in mild and moderate AD. The decrease in the CBF was not as obvious as that in the mACh-R and the CMRGlc. Our study thus suggested that the mACh-R decreased in patients with AD, and that the 18FDG PET was the most sensitive method for detecting the degenerative regions in patients with AD. (author)

264

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

265

FGF growth factor analogs  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

Zamora, Paul O. (Gaithersburg, MD); Pena, Louis A. (Poquott, NY); Lin, Xinhua (Plainview, NY); Takahashi, Kazuyuki (Germantown, MD)

2012-07-24

266

Entanglement and thermodynamical analogies  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We provide some new properties of entanglement of formation. In particular, we obtain an additive lower bound for entanglement of formation. Subsequently we develop the concept of local orthogonality of ensembles which leads to the mixed states with distillable entanglement equal to entanglement of formation. Then we consider thermodynamical analogies within the entanglement processing domain. Especially, we exploit analogy entanglement -- energy. In this scheme the total en...

Horodecki, Pawel; Horodecki, Ryszard; Horodecki, Michal

1998-01-01

267

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 (WHtR, or waist-to-hip-ratio (WHpR in identifying prevalent and predicting incident diabetes. Results The cross-sectional analyses were performed on a sample included 3,682 men and 4,989 women who were not pregnant, aged ? 20 years. According to the age (? 50 and For longitudinal analyses, a total of 5,018 non-diabetic subjects were followed for ~6 years. The ORs of BMI, WHpR, and WHtR were the same as those of LAP in both sexes and across age groups; except in young men where LAP was superior to the BMI. AROCs of LAP were relatively the same as anthropometric adiposity measures. Conclusions LAP was a strong predictor of diabetes and in young individuals had better predictability than did BMI; it was, however, similar to WHpR and WHtR in prediction of incident diabetes.

Azizi Fereidoun

2010-05-01

268

Effects of metoclopramide on duodenal motility and flow events, glucose absorption, and incretin hormone release in response to intraduodenal glucose infusion.  

Science.gov (United States)

The contribution of small intestinal motor activity to nutrient absorption is poorly defined. A reduction in duodenal flow events after hyoscine butylbromide, despite no change in pressure waves, was associated with reduced secretion of the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) and a delay in glucose absorption. The aim of this study was to investigate the effect of metoclopramide on duodenal motility and flow events, incretin hormone secretion, and glucose absorption. Eight healthy volunteers (7 males and 1 female; age 29.8 ± 4.6 yr; body mass index 24.5 ± 0.9 kg/m²) were studied two times in randomized order. A combined manometry and impedance catheter was used to measure pressure waves and flow events in the same region of the duodenum simultaneously. Metoclopramide (10 mg) or control was administered intravenously as a bolus, followed by an intraduodenal glucose infusion for 60 min (3 kcal/min) incorporating the ¹?C-labeled glucose analog 3-O-methylglucose (3-OMG). We found that metoclopramide was associated with more duodenal pressure waves and propagated pressure sequences than control (P OMG activity did not differ between the two study days. Metoclopramide was associated with increased plasma concentrations of GLP-1 (P < 0.05) and GIP (P = 0.07) but lower plasma insulin concentrations (P < 0.05). We concluded that metoclopramide was associated with increased frequency of duodenal pressure waves but no change in duodenal flow events and glucose absorption. Furthermore, GLP-1 and GIP release increased with metoclopramide, but insulin release paradoxically decreased. PMID:20829521

Kuo, Paul; Bellon, Max; Wishart, Judith; Smout, André J; Holloway, Richard H; Fraser, Robert J L; Horowitz, Michael; Jones, Karen L; Rayner, Christopher K

2010-12-01

269

Thermal stability of water and hydroxyl on the surface of the Moon from temperature-programmed desorption measurements of lunar analog materials  

Science.gov (United States)

The adsorption of molecular water onto lunar analog materials was investigated under ultra-high vacuum with the goal to better understand the thermal stability and evolution of water on the lunar surface. Temperature-programmed desorption (TPD) experiments show that lunar-analog basaltic-composition glass is hydrophobic, with water-water interactions dominating over surface chemisorption. This suggests that lunar agglutinates will tend not to adsorb water at temperatures above where water clusters and multilayer ice forms. The basalt JSC-1A lunar mare analog, which is a complex mixture of minerals and glass, adsorbs water above 180 K with an adsorption profile that extends to 400 K, showing evidence for a continuum of water adsorption sites. Bancroft albite adsorbs more water, more strongly, than JSC-1A, with a well-defined desorption peak near 225 K. This suggests that mineral surfaces will adsorb more water than mare or mature (glassy, agglutinate rich) surfaces and may explain the association of water with fresh feldspathic craters at high latitudes. The activation energies for the thermal desorption of water from these materials were determined, and along with values from the literature, used to model the grain-to-grain migration of water within the lunar regolith. These models suggest that a combination of recombinative desorption of hydroxyl along with molecular desorption of water and its subsequent migration within and out of the regolith may explain observed diurnal variations in the distribution of water and hydroxyl on the illuminated Moon.

Hibbitts, C. A.; Grieves, G. A.; Poston, M. J.; Dyar, M. D.; Alexandrov, A. B.; Johnson, M. A.; Orlando, T. M.

2011-05-01

270

Radioimmunoassay for 6-D-tryptophan analog of luteinizing hormone-releasing hormone: measurement of serum levels after administration of long-acting microcapsule formulations  

International Nuclear Information System (INIS)

A sensitive and specific radioimmunoassay for [6-D-tryptophan]luteinizing hormone-releasing hormone ([D-Trp6]LH-RH) was developed and used for following the rate of liberation of [D-Trp6]LH-RH from a long-acting delivery systems based on a microcapsule formulation. Rabbit antibodies were generated against [D-Trp6]LH-RH conjugated to bovine serum albumin with glutaraldehyde. Crossreactivity with LH-RH was less than 1%; there was no significant cross-reactivity with other peptides. The minimal detectable dose of [D-Trp6]LH-RH was 2 pg per tube. In tra- and interassay coefficients of variation were 8% and 10%, respectively. The radioimmunoassay was suitable for direct determination of [D-Trp6]LH-RH in serum, permitting the study of blood levels of the analog after single injections into normal men and after one-a-month administration of microcapsules to rats. In men, 90 min after subcutaneous injection of 250 ?g of the peptide, serum [D-Trp6]LH-RH rose to 6-12 ng/ml. Luteinizing hormone was increased 90 min and 24 hr after the administration of the analog. Several batches of microcapsules were tested in rats and the rate of release of [D-Trp6]LH-RH was followed. The improved batch of microcapsules of [D-Trp6]LH-RH increased serum concentrations of the analog for 30 days or longer after intramuscular injection

271

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

272

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

273

Glucose - An Annotated Bibliography.  

Science.gov (United States)

The annotated bibliography contains 905 citations. About 90 percent of the articles annotated pertain to glucose analytical methodology and the other 10 percent consists of clinical articles which pertain to the glucose tolerance test and normal values. T...

A. M. Polk, C. Lewis, N. Radin, N. M. Richardson

1976-01-01

274

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Nephropathy) Gastroparesis Mental Health Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women ... Living With Diabetes > Treatment and Care > Blood Glucose Testing Share: Print Page Text Size: A A A ...

275

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 ... glucose) Dawn Phenomenon Checking for Ketones Tight Diabetes Control donate en -- Be TWICE as AWESOME! - 2014-nov- ...

276

[Transepithelial transport of glucose].  

Science.gov (United States)

Epithelia serve as barriers among various compartments in the body. Transepithelial transport of glucose across the barrier epithelial layer is mediated by membrane proteins called glucose transporters. Two types of glucose transporters have been identified: Na(+)-dependent glucose cotransporters (SGLT family), and facilitated-diffusion glucose transporters (GLUT family). These transporters play important roles in the sugar absorption in the intestinal epithelium, sugar reabsorption in the kidney tubule cells, and transfer of glucose across the blood-tissue barriers. In addition to glucose transporters, connexins of gap junctions mediate the transfer of glucose in the double-epithelial cell layer found in the ciliary body and the rat placenta. Polarized localization of transporters and connexins is the structural basis of the vectorial transfer of sugars across the barrier epithelial cell layers. Various techniques of molecular and cell biology have been applied to elucidate the molecular mechanism of such polarized localization. PMID:9844339

Takata, K

1998-10-01

277

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 ... www.diabetes.org > Living With Diabetes > Treatment and Care > Blood Glucose Testing Share: Print Page Text Size: ...

278

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 & ...

279

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 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

280

[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

 
 
 
 
281

Assessment of the [18F] fluorodeoxyglucose kinetic model in calculations of myocardial glucose metabolism during ischemia  

International Nuclear Information System (INIS)

The lumped constant - a term in the operational equation of the Sokoloff tracer kinetic model for deoxyglucose that accounts for the difference in transport and phosphorylation between glucose and its analog, deoxyglucose - could potentially vary from normal to ischemic conditions in the heart. To test the stability of the lumped constant during ischemia, the authors evaluated the ratio of the extraction fraction for (F-18)-fluorodeoxyglucose (FDG) to that for glucose(a measure of the lumped constant if there is no significant dephosphorylation of FDG-6-PO4) and the rate constant for dephosphorylation of FDG-6-4(k4) in the isolated, arterially perfused interventricular septum of the rabbit during moderate and severe demand-induced and reduced-flow ischemias. The lumped constant and k4* in each of the four ischemic experimental conditions were found not to be significantly different from the value obtained from the nonischemic controls

282

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

283

Hyperglycemia (High Blood Glucose)  

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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 ...

284

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... how often you should check and what your blood glucose levels should be. Checking your blood and then treating ... I Treat Hyperglycemia? You can often lower your blood glucose level by exercising. However, if your blood glucose is ...

285

Underestimation of glucose turnover corrected with high-performance liquid chromatography purification of [6-3H]glucose  

International Nuclear Information System (INIS)

We have recently reported that during infusion of commercially available [6-3H]glucose, a radioactive nonglucose contaminant may accumulate in plasma causing errors in the measurement of glucose turnover. To determine whether purification of this tracer by HPLC (high-performance liquid chromatography) before infusion would eliminate the contaminant in plasma and remove the underestimation of glucose turnover reported during hyperinsulinemia, four normal subjects each underwent two 5-h euglycemic clamps during infusion of insulin (1 mU.kg-1.min-1). Glucose turnover was measured with either commercially available [6-3H]glucose or with HPLC-purified [6-3H]glucose. HPLC analysis of samples from the clamps done with commercially available [6-3H]glucose showed that 9.7% of the infused tracer and 26% of the plasma glucose 3H radioactivity were contaminants. In contrast, no contaminant was observed in the plasma during infusion of HPLC-purified [6-3H]glucose. During the last hour of the clamp, mean glucose turnover using commercially available [6-3H]glucose was less (P less than 0.01) than the mean glucose infusion rate (7.6 +/- 0.3 vs. 10.5 +/- 0.3 mg.kg-1.min-1) yielding apparent negative (P less than 0.001) hepatic glucose release. In contrast, when HPLC-purified [6-3H]glucose was employed, glucose turnover equaled the glucose infusion rate (10.4 +/- 0.9 vs. 10.2 +/- 0.9 mg.kg-1.min-1) and hepatic glucose release was no longer negative. We conclude that removal of a tritiated nonglucose contaminant in [6-3H]glucose by HPLC yields correct estimations of glucose turnover at steady state

286

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

287

Analog layout synthesis  

CERN Document Server

Integrated circuits are fundamental electronic components in biomedical, automotive and many other technical systems. A small, yet crucial part of a chip consists of analog circuitry. This part is still in large part designed by hand and therefore represents not only a bottleneck in the design flow, but also a permanent source of design errors responsible for re-designs, costly in terms of wasted test chips and in terms of lost time-to-market. Layout design is the step of the analog design flow with the least support by commercially available, computer-aided design tools. This book provides a

Graeb, Helmut E

2010-01-01

288

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 low ?-amylase activity. A follow up experiment was conducted to quantify the 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

289

Novel PEGylated basal insulin LY2605541 has a preferential hepatic effect on glucose metabolism.  

Science.gov (United States)

The impact of the novel basal insulin LY2605541 (LY) on hepatic and nonhepatic glucose uptake (non-HGU) was evaluated. Conscious dogs underwent euglycemic clamps with tracer and hepatic balance measurements. Clamp period infusions were peripheral venous regular insulin (0.1 nmol ? kg(-1) ? h(-1) [control], n = 6) or LY (bolus [nmol/kg], continuous [nmol ? kg(-1) ? h(-1)]: 0.5, 0.5 [n = 6]; 0.375, 0.375 [n = 5]; 0.25, 0.25 [n = 4]), somatostatin, and glucose, as well as intraportal glucagon (basal). During the clamp, the dogs switched from net hepatic glucose output to uptake (rates reached 2.1 ± 1.2, 0.9 ± 2.1, 8.6 ± 2.3, and 6.0 ± 1.1 µmol ? kg(-1) ? min(-1) within 5 h in control, LY0.25, LY0.375, and LY0.5, respectively). Non-HGU in LY increased less than in control; the ratio of change from basal in non-HGU to change in net hepatic glucose balance, calculated when glucose infusion rates (GIRs) were ~20 µmol ? kg(-1) ? min(-1) in all groups, was higher in control (1.17 ± 0.38) versus LY0.25 (0.39 ± 0.33), LY0.375 (-0.01 ± 0.13), and LY0.5 (-0.09 ± 0.07). Likewise, the change from baseline in glucose Rd-to-Ra ratio was greatest in control (1.4 ± 0.3 vs. 0.6 ± 0.4, 0.5 ± 0.2, and 0.6 ± 0.2 in LY0.25, LY0.375, and LY0.5, respectively). In contrast to exogenously administered human insulin, LY demonstrated preferential hepatic effects, similar to endogenously secreted insulin. Therefore, the analog might reduce complications associated with current insulin therapy. PMID:24089512

Moore, Mary Courtney; Smith, Marta S; Sinha, Vikram P; Beals, John M; Michael, M Dodson; Jacober, Scott J; Cherrington, Alan D

2014-02-01

290

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

291

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

292

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

293

Video Analog Signal Divider  

Science.gov (United States)

Video analog signal divider produces black-and-white composite video signal based on color ratio. Device inexpensive, uses signal from standard red/green/blue camera as input. Used to produce quantitative thermal images of two-color phosphor coatings.

Buck, Gregory M.

1988-01-01

294

Differential associations of oral glucose tolerance test-derived measures of insulin sensitivity and pancreatic ?-cell function with coronary artery calcification and microalbuminuria in type 2 diabetes.  

Science.gov (United States)

OBJECTIVE We evaluated relationships of oral glucose tolerance testing (OGTT)-derived measures of insulin sensitivity and pancreatic ?-cell function with indices of diabetes complications in a cross-sectional study of patients with type 2 diabetes who are free of overt cardiovascular or renal disease. RESEARCH DESIGN AND METHODS A subset of participants from the Penn Diabetes Heart Study (n = 672; mean age 59 ± 8 years; 67% male; 60% Caucasian) underwent a standard 2-h, 75-g OGTT. Insulin sensitivity was estimated using the Matsuda Insulin Sensitivity Index (ISI), and ?-cell function was estimated using the Insulinogenic Index. Multivariable modeling was used to analyze associations between quartiles of each index with coronary artery calcification (CAC) and microalbuminuria. RESULTS The Insulinogenic Index and Matsuda ISI had distinct associations with cardiometabolic risk factors. The top quartile of the Matsuda ISI had a negative association with CAC that remained significant after adjusting for traditional cardiovascular risk factors (Tobit ratio -0.78 [95% CI -1.51 to -0.05]; P = 0.035), but the Insulinogenic Index was not associated with CAC. Conversely, the highest quartile of the Insulinogenic Index, but not the Matsuda ISI, was associated with lower odds of microalbuminuria (OR 0.52 [95% CI 0.30-0.91]; P = 0.022); however, this association was attenuated in models that included duration of diabetes. CONCLUSIONS Lower ?-cell function is associated with microalbuminuria, a microvascular complication, while impaired insulin sensitivity is associated with higher CAC, a predictor of macrovascular complications. Despite these pathophysiological insights, the Matsuda ISI and Insulinogenic Index are unlikely to be translated into clinical use in type 2 diabetes beyond established clinical variables, such as obesity or duration of diabetes. PMID:23949560

Mulvey, Claire K; McNeill, Ann M; Girman, Cynthia J; Churchill, Timothy W; Terembula, Karen; Ferguson, Jane F; Shah, Rachana; Mehta, Nehal N; Qasim, Atif N; Rickels, Michael R; Reilly, Muredach P

2014-01-01

295

Early change in glucose metabolic rate measured using FDG-PET in patients with high-grade glioma predicts response to temozolomide but not temozolomide plus radiotherapy  

International Nuclear Information System (INIS)

Purpose: To compare the ability of positron emission tomography (PET) to predict response to temozolomide vs. temozolomide plus radiotherapy. Methods and Materials: Nineteen patients with high-grade glioma (HGG) were studied. Patients with recurrent glioma received temozolomide 75 mg/m2 daily for 7 weeks (n = 8). Newly diagnosed patients received temozolomide 75 mg/m2 daily plus radiotherapy 60 Gy/30 fractions over 6 weeks, followed by six cycles of adjuvant temozolomide 200 mg/m2/day (Days 1-5 q28) starting 1 month after radiotherapy (n = 11). [18F]Fluorodeoxyglucose ([18F]FDG) PET scan and magnetic resonance imaging (MRI) were performed at baseline, and 7 and 19 weeks after initiation of temozolomide administration. Changes in glucose metabolic rate (MRGlu) and MRI response were correlated with patient survival. Results: In the temozolomide-alone group, patients who survived >26 vs. ?26 weeks showed a greater reduction in MRGlu measured at 7 weeks with median changes of -34% and -4%, respectively (p = 0.02). PET responders, defined as a reduction in MRGlu ?25%, survived longer than nonresponders with mean survival times of 75 weeks (95% CI, 34-115 vs. 20 weeks (95% CI, 14-26) (p = 0.0067). In the small group of patients studied, there was no relationship between MRI response and survival (p = 0.52). For patients receiving temozolomide plus radiotherapy, there was no difference in survival between PET responderence in survival between PET responders and nonresponders (p = 0.32). Conclusions: Early changes in MRGlu predict response to temozolomide, but not temozolomide plus radiotherapy

296

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 | Language: 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

297

Spontaneous Student-Generated Analogies  

Science.gov (United States)

The purposes of this qualitative study were (a) to investigate the factors that support the generation of spontaneous analogies (SAs) by students, and (b) to investigate the factors that interfere with comprehension of the analogy target of an SA. To promote the generation of SAs, eight algebra-based physics students were asked to participate in two group problem-solving sessions and one individual explaining session. Overall, 18 spontaneous analogies were generated. Two factors appeared to support the spontaneous generation of analogies: (1) sufficient prior understanding of the analogy target, and (2) the existence of previous analogical examples from other students. Two factors appeared to interfere with the comprehension of the SA analogy target: (1) an incorrect perception of the type of analogy between target and base (attributes, relationships), and (2) an incorrect understanding of the analogy base.

Sandifer, Cody

2005-10-20

298

Clinical utility of insulin and insulin analogs.  

Science.gov (United States)

Diabetes is a pandemic disease characterized by autoimmune, genetic and metabolic abnormalities. While insulin deficiency manifested as hyperglycemia is a common sequel of both Type-1 and Type-2 diabetes (T1DM and T2DM), it does not result from a single genetic defect--rather insulin deficiency results from the functional loss of pancreatic ? cells due to multifactorial mechanisms. Since pancreatic ? cells of patients with T1DM are destroyed by autoimmune reaction, these patients require daily insulin injections. Insulin resistance followed by ? cell dysfunction and ? cell loss is the characteristics of T2DM. Therefore, most patients with T2DM will require insulin treatment due to eventual loss of insulin secretion. Despite the evidence of early insulin treatment lowering macrovascular (coronary artery disease, peripheral arterial disease and stroke) and microvascular (diabetic nephropathy, neuropathy and retinopathy) complications of T2DM, controversy exists among physicians on how to initiate and intensify insulin therapy. The slow acting nature of regular human insulin makes its use ineffective in counteracting postprandial hyperglycemia. Instead, recombinant insulin analogs have been generated with a variable degree of specificity and action. Due to the metabolic variability among individuals, optimum blood glucose management is a formidable task to accomplish despite the presence of novel insulin analogs. In this article, we present a recent update on insulin analog structure and function with an overview of the evidence on the various insulin regimens clinically used to treat diabetes. PMID:23584214

Sanlioglu, Ahter D; Altunbas, Hasan Ali; Balci, Mustafa Kemal; Griffith, Thomas S; Sanlioglu, Salih

2013-01-01

299

Clinical studies for improving radiotherapy with 2-deoxy-D-glucose: Present status and future prospects  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Higher rates of glucose usage generally correlate with poor prognosis in several types of malignant tumours. Experimental studies (both in vitro and in vivo) have shown that 2-deoxy-D-glucose (2-DG), a glucose analog and glycolytic inhibitor, enhances radiation-induced damage selectively in tumor cells while protecting normal cells, thereby suggesting that 2-DG can be used as a differential radiomodifier to improve the efficacy of radiotherapy. Clinical trials undertaken to study the feasibil...

Dwarakanath B; Singh Dinesh; Banerji Ajit; Sarin Rajiv; Venkataramana N; Jalali R; Vishwanath P; Mohanti B; Tripathi R.; Kalia V; Jain Viney

2009-01-01

300

Interaction of ZnS nanoparticles with flavins and glucose oxidase: A fluorimetric investigation  

International Nuclear Information System (INIS)

Interactions of luminescence, water soluble ZnS nanoparticles (NPs) with flavins and glucose oxidase have been thoroughly investigated through optical spectroscopy. The photoluminescence of ZnS nanoparticles was quenched severely (?60%) by riboflavin while other flavins such as flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) show quenching to different extents under analogous conditions. However, interestingly no effect in luminescence intensity of ZnS NPs was observed with protein bound flavins such as in glucose oxidase. Fluorescence lifetime measurement confirmed the quenching to be static in nature. Scavenging of photo-generated electron of ZnS nanoparticles by the flavin molecules may be attributed to the decrease in luminescence intensity. Quenching of ZnS nanoparticles with flavins follows the linear Stern–Volmer plot. The Stern–Volmer constants decreased in the following order: KS?V (Riboflavin)> KS?V (FAD)> KS?V (FMN). This interaction study could generate useful protocol for the fluorimetric determination of riboflavin (vitamin B2) content and also riboflavin status in biological systems. - Highlights: ? Unique interaction specificity of ZnS nanoparticles with flavins has been explored. ? Unlike protein-bound flavin, fluorescence of free flavins was quenched by ZnS nanoparticles. ? FMN and FAD show quenching to different extents under analogous conditions. ? Fluorescence lifeti ? Fluorescence lifetime measurement confirmed the quenching to be static in nature. ? This study is useful for probing riboflavin in biological systems.

 
 
 
 
301

Molecular dynamics of confined glucose solutions.  

Science.gov (United States)

Silica gels containing solutions of glucose in heavy water at different concentrations have been prepared by a sol-gel method. Dynamical studies with quasielastic neutron scattering, compared with previous results on bulk solutions, show that the dynamics of the glucose molecules are not appreciably affected by the confinement, even though the gels behave macroscopically as solid materials. Small-angle neutron-scattering spectra on the same systems, fitted with a fractal model, yield a correlation length that decreases from 20 to 2.5 nm with increasing glucose concentration, suggesting a clustering of glucose molecules in concentrated solutions that is consistent with the dynamical measurements. These two sets of results imply that 20 nm is an upper limit for the scale at which the dynamics of glucose molecules in solution are affected by confinement. PMID:15945690

Lelong, Gérald; Price, David L; Douy, André; Kline, Steve; Brady, John W; Saboungi, Marie-Louise

2005-04-22

302

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy ...

303

Glucose metabolism in a rat mammary adenocarcinoma  

International Nuclear Information System (INIS)

Full text: Tumor hypoxia, which decreases therapy response is common in tumors. Glucose metabolism is closely tied to tumor oxygenation and alteration of its metabolism could improve tumor oxygenation. The objective of the study was to compare tissue pharmacokinetics of 14C-2-deoxyglucose (14C2DG) and 14C-glucose in an adenocarcinoma (R3230Ac) and normal control tissue (subcutis:SQ) using a novel fiberoptic scintillation detector. Fischer 344 rats with R3230Ac tumors were anesthetized with Isoflurane and detectors were inserted. Baseline data was acquired for 45 minutes, then 14C2DG or 14C-glucose (i.v.) was injected and data was acquired for 3 hours. After 100mCi of 14C2DG both tissues reached peaks (R3230Ac, 0.4mCi/g; SQ, 0.75mCi/g) 20 minutes post-injection that remained stable for 3 hours. With 200mCi 14C2DG R3230Ac peaked and plateaued at 1.75mCi/g by 50 minutes. SQ peaked (2.25mCi/g) at 20 minutes and decreased to a stable plateau (0.75mCi/g) at 50 minutes. Kinetics of 14C-glucose were different from 14C2DG. R3230Ac and SQ increased over 20 minutes, reaching peaks of 2.4mCi/g and 1.5mCi/g, respectively. A slow decrease followed, but tumor signal (1.25mCi/g) remained higher than SQ (0.5mCi/g). Kinetics of 14C2DG and 14C-glucose were distinctly different. In SQ a wash-in/wash-out effect was observed at 200mCi of 14C2DG. In tumor 00mCi of 14C2DG. In tumor 14C2DG accumulated to a plateau (1.75mCi/g) that persisted out to 3 hours. 14C-glucose signal declined below 14C2DG signal in both tissues, suggesting they both metabolize 14C-glucose and excrete 14C-containing metabolites. PET can assess flouride-deoxyglucose uptake in tumors, which is analogous to our 14C2DG studies. However, PET cannot provide data on glucose metabolism and excretion because there is not a metabolizable fluorinated-glucose analogue that is imageable by PET. In summary, this novel detector has the unique capability to evaluate real-time accumulation, metabolism, and excretion of radiolabeled glucose in tissues before and after metabolic manipulation

304

Four methods for glucose assay compared for various glucose concentrations and under different clinical conditions.  

Science.gov (United States)

Glucose was measured by the ferricyanide, the Beckman glucose oxidase, and the hexokinase procedures in 228 plasma samples taken during standard oral glucose-tolerance tests in 17 normal subjects and in 21 chemical diabetics. The neocuproine method was also used to measure glucose concentration in 156 samples (78 before and 78 after dialysis) collected from six diabetic and uremic patients who were on maintenance hemodialysis. Ferricyanide in all conditions and neocuproine in uremic patients overestimated glucose concentrations over the entire experimental range as compared with either enzymic method. This bias or systematic error of the reducing vs the enzymic procedures, due to nonglucose reducing substances ("saccharoids"), becomes considerably greater when their concentration is increased as in chronic uremia. Also, the inverse relation between glucose concentration and overestimation of glucose by the reducing methods has been detected. With respect to the hexokinase method, a mild but significant underestimate of glucose oxidase readings has been observed for higher glucose concentrations. We find neocuproine to be the most imprecise of these procedures. PMID:7139920

Giampietro, O; Pilo, A; Buzzigoli, G; Boni, C; Navalesi, R

1982-12-01

305

Renormgroup analogies in astrophysics  

International Nuclear Information System (INIS)

New semigroup relations describing solutions of nonstaionary nonlinear problems of the radiation transfer theory are established. They lead to an effective apparatus of analysis, different from classical ones, even in stationary and linear cases. Advantages of the semigroup apparatus are discussed. The role of the Ambarzumyan invariance principle and relation with the Shirkov functional self-similarity is stated. A wide variety of mathematical analogies with the renormalization group and problems of the quantum field theory is established. On the basis of these analogies an attempt is made to transpose some physical conclusions from one theory into another. An astrophysical example of the inverse problem of determination of the stellar flare frequency distribution function in aggregates is discussed. A possibility of using the semigroup approach in the problem of stellar system dynamics is noted. the studies of other authors on application of the renormalization group approach to astrophysical problems are observed. The semigroup approach foreruns new possibilities of effective study, in particular, by analog simulation and borrowing of methods and results

306

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  

Directory of Open Access Journals (Sweden)

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.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 majority 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

2000-01-01

307

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

308

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

309

Continuous Glucose Monitoring  

Science.gov (United States)

... too high However, RT-CGM has some drawbacks: Costs more than blood glucose meter testing May not be covered by health insurance Is not as accurate as standard blood glucose meters ... of RT-CGM may be worth the costs for many patients with type 1 diabetes. The ...

310

How accurate is glucose analysis in the presence of multiple interfering substances in the neonate? (glucose analysis and interfering substances).  

Science.gov (United States)

Whole blood glucose testing by reagent sticks is inaccurate at low plasma glucose concentrations and with varying hematocrit. Both conditions are frequently seen in newborn infants. Therefore plasma glucose analysis is the preferred method for newborn glucose monitoring. We encountered unanticipated difficulties in plasma glucose measurement by the automated hexokinase method caused by the combinations of plasma free hemoglobin, bilirubin, and plasma triglycerides, which are frequently elevated in newborn plasma. We determined the adverse effects of various combinations of these interfering substances on glucose analysis by the hexokinase method and demonstrated that accurate analysis is possible by a 1:1 plasma dilution only at high plasma glucose levels but not at the more critical low plasma glucose concentration. The dilution reduced the number of repeat specimens required in newborns. But 1:1 plasma dilution overestimated the glucose levels at low plasma glucose values, and therefore this automated hexokinase method is not suitable for glucose analysis in the newborn. Glucose-oxidase remains the method of choice for plasma glucose analysis in neonates. This information is important because using this hexokinase methodology, one might miss hypoglycemia in the newborn. PMID:8926561

Jain, R; Myers, T F; Kahn, S E; Zeller, W P

1996-01-01

311

Glucose Biosensor Using Selected Indonesian Bacteria  

Directory of Open Access Journals (Sweden)

Full Text Available Microbial glucose sensors have been developed using Escherichia coli bacterial strains from Japan. However, there is interest in developing local bacteria as glucose sensors in Indonesia. In this research, the stability and the potential of a selected number of Indonesian bacteria as glucose biosensors was explored. Results of this study indicate that three of them, E. coli, Bacillus subtilis, and Thermus filiformis exhibit properties of high viability and stability at high temperature (30-60 ºC. Spectrophotometrical and electrochemical measurements showed significant absorbance values and highly stable current features for E. coli as indicated by its high capacity to produce glucose dehydrogenase. E. coli, B. subtilis, and T. filiformis produced currents of 3.25 µA, 0.2 µA, and 0.02 µA respectively, and E. coli also produced a much higher activity of glucose dehydrogenase. Electrochemical measurement using E. coli-modified carbon paste electrode allowed the determination of glucose concentration of up to 20 mM. Therefore, Indonesian E. coli has a high stability and can be used as a glucose biosensor

DYAH ISWANTINI

2011-03-01

312

Vorrichtung und Verfahren zur effizienten Analog-Zu-Digital-Wandlung  

Digital Repository Infrastructure Vision for European Research (DRIVER)

DE 102007056732 A1 UPAB: 20090609 NOVELTY - The converter (150) has a compensation device (152) for subjecting an analog measuring value with a correction value depending upon a combination signal (154) to form a modified measuring value (156). An analog filter (158) filters the modified measuring value to obtain a filtered measuring value (160). A digitizer (40) produces a digital value (162) depending upon the filtered measuring value. A feedback device (164) forms the combination signal by...

Huppertz, J.

2007-01-01

313

Continuous glucose monitoring in small animals.  

Science.gov (United States)

The use of continuous glucose monitoring systems in veterinary patients is summarized and discussed. The current clinical uses in veterinary medicine, including monitoring of hospitalized/sick diabetic patients, long-term monitoring of stable diabetic patients, anesthetized patients, and other patients with altered blood glucose homeostasis are presented. The most important advantage of these systems over intermittent blood glucose measurements is that they facilitate detection of brief periods of hypoglycemia and provide information overnight. The accuracy and advantages/disadvantages compared with traditional monitoring are addressed. The technology involved in the currently available monitoring systems is also discussed. PMID:23522178

Surman, Sean; Fleeman, Linda

2013-03-01

314

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

315

Korean red ginseng improves glucose control in subjects with impaired fasting glucose, impaired glucose tolerance, or newly diagnosed type 2 diabetes mellitus.  

Science.gov (United States)

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 2-h oral glucose tolerance tests (OGTTs) at baseline and after the 12-week intervention. After the intervention, the test group showed a significant decrease in serum levels of glucose at 30?min (-22.24±10.77?mg/dL) and whole blood levels of glucose at 30?min (-17.52±5.22?mg/dL). In addition, the test group tended to have lower whole blood levels of glucose at 0?min and glucose area under curve (AUC). However, the placebo group did not show any changes in blood glucose-related indices. The changes (difference from baseline) in serum glucose levels at 30?min, whole blood glucose levels at 60?min, and glucose AUC during OGTTs in the test group exhibited a tendency toward a decrease from those in the placebo group. There were significant decreases or trends toward a decrease in both serum insulin and C-peptide concentrations at most time intervals in the test group. In conclusion, KRG supplementation (5?g/day) may be beneficial for controlling serum and whole blood glucose levels compared with placebo among patients with IFG, IGT, or T2DM. PMID:24456363

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

2014-01-01

316

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

317

On the role of glucose-dependent insulintropic polypeptide in postprandial metabolism in humans  

DEFF Research Database (Denmark)

We investigated the role of glucose-dependent insulintropic polypeptide (GIP) in the regulation of gastric emptying (GE), appetite, energy intake (EI), energy expenditure (EE), plasma levels of triglycerides (TAG), and free fatty acids (FFA) in humans. First, 20 healthy males received intravenous infusion of GIP (0.8 pmol.kg(-1).min(-1)) or saline for 300 min during and after a fixed meal (protocol 1). GE was measured using paracetamol, appetite sensations using visual analog scales, EE using indirect calorimetry, and EI during a subsequent ad libitum meal (at 300 min). Next, 10 healthy males received intravenous infusions of Intralipid, glucose, or Intralipid plus glucose, with and without GIP (1.5 pmol.kg(-1).min(-1)) for 300 min (protocol 2). In protocol 1, GIP did not have any effect on GE, EI, EE, removal of TAG, or FFA and did not influence the subjective feeling of hunger, satiety, fullness or prospective food consumption compared with saline. In protocol 2, no difference was seen in the plasma TAG on Intralipid + GIP/saline and Intralipid + glucose + GIP/saline days. FFA concentrations were lower on Intralipid + glucose + GIP/saline days (P <0.05) compared with Intralipid + GIP/saline days and on Intralipid + GIP day (P <0.004) compared with Intralipid + saline day. Insulin increased on all GIP days compared with saline days (P <0.05). In conclusion, while confirming its insulinotropic effects, these data suggest that GIP does not affect GE, appetite, energy intake, EE, or the clearance rate of the applied TAG formulation in humans. However, both insulin and GIP lower post-Intralipid FFA concentration, GIP probably via stimulation of insulin secretion, increasing FFA reesterification.

Asmar, Meena; Tangaa, Winnie

2010-01-01

318

Microwave dielectric resonator biosensor for aqueous glucose solution  

Science.gov (United States)

We report a near-field microwave biosensor based on a dielectric resonator to detect glucose concentration. A microwave biosensor with a high Q dielectric resonator allows observation of the small variation of the glucose concentration by measuring the shift of the resonance frequency and the microwave reflection coefficient S11. We observed the concentration of glucose with a detectable resolution up to 5mg/ml at an operating frequency of about f =1.68GHz. The change in the glucose concentration is directly related to the change in the reflection coefficient due to the electromagnetic interaction between the dielectric resonator and the glucose solution.

Kim, Jongchul; Babajanyan, Arsen; Hovsepyan, Artur; Lee, Kiejin; Friedman, Barry

2008-08-01

319

Kinetic validation of 6-NBDG as a probe for the glucose transporter GLUT1 in astrocytes.  

Science.gov (United States)

In recent years, the use of fluorescent glucose analogs has allowed the study of rapid transport modulation in heterogeneous cell cultures and complex tissues. However, the kinetic behavior of these tracers is not conventional. For instance, the fluorescent glucose analog 6-NBDG permeates the cell 50-100 times slower than glucose but the uptake of 6-NBDG is almost insensitive to glucose, an observation that casts doubts as to the specificity of the uptake pathway. To investigate this apparent anomaly in cultured astrocytes, which are rich in the glucose transporter GLUT1, we first estimated the kinetic parameters of 6-NBDG uptake, which were then incorporated into the kinetic model of GLUT1. The main outcome of the analysis was that 6-NBDG binds to GLUT1 with 300 times higher affinity than glucose, which explains why its uptake is not efficiently displaced by glucose. The high binding affinity of 6-NBDG also explains why cytochalasin B is less effective at inhibiting 6-NBDG uptake than at inhibiting glucose uptake. We conclude that 6-NBDG, used at low concentrations, permeates into astrocytes chiefly through GLUT1, and advise that the exofacial GLUT1 inhibitor 4,6-ethylidine-D-glucose be used, instead of glucose, as the tool of choice to confirm the specificity of 6-NBDG uptake. PMID:19393014

Barros, Luis Felipe; Bittner, Carla X; Loaiza, Anitsi; Ruminot, Iván; Larenas, Valeria; Moldenhauer, Hans; Oyarzún, Carolina; Alvarez, Mauro

2009-05-01

320

lyoluminescence experiments on mannose and glucose  

International Nuclear Information System (INIS)

As lyoluminescence seems to present interesting characteristics for several applications in dosimetry, the authors have performed some experiments using mannose and glucose. The characteristics of pure mannose and glucose were determined; and parameter like selection of the appropriate solvent, the granulometry of the powders, the amount of sugar used for each measurement were studied. The threshold dose was of the order of 5 Gy for both sugars. (author)

 
 
 
 
321

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

322

Insulin release is glucose anomeric specific in the human.  

Science.gov (United States)

The alpha-glucose anomer produces a greater insulin release than beta-glucose in various animal models. These glucose anomers were dissolved rapidly and administered intravenously to human volunteers at a high dose (0.5 g/kg) over a 3-min period or a low dose (3.5 g) over a 20-s period. Blood samples were obtained at frequent time intervals for measurement of whole blood glucose (ferricyanide), plasma glucose (beta-glucose oxidase) and serum immunoreactive insulin. The high-dose infusion test showed no differences between the anomers of either blood glucose or serum insulin levels. However, at the lower dose, the alpha-glucose anomer stimulated a significantly greater insulin release than did beta-glucose. It is concluded that the alpha-glucose anomer stimulates a greater insulin release than the beta-glucose anomer in human subjects at low but not at high doses intravenously and that this response is not apparently related to approximations of the degree of mutarotation. These results suggest that a steric specific glucose receptor site exists on the beta-cell as a rapid insulin release trigger, although the alpha-anomer does not exclusively produce this stimulation. PMID:947950

Rossini, A A; Soeldner, J S

1976-04-01

323

Measurements of insulin secretory capacity and glucose tolerance to predict pancreatic beta-cell mass in vivo in the nicotinamide/streptozotocin Göttingen minipig, a model of moderate insulin deficiency and diabetes.  

Science.gov (United States)

Knowledge about beta-cell mass and/or function could be of importance for the early diagnosis and treatment of diabetes. However, measurement of beta-cell function as an estimate of beta-cell mass is currently the only method possible in humans. The present study was performed to investigate different functional tests as predictors of beta-cell mass in the Göttingen minipig. beta-cell mass was reduced in the Göttingen minipig with a combination of nicotinamide (100 [n = 6], 67 [n = 25], 20 [n = 2], or 0 mg/kg [n = 4]) and streptozotocin (125 mg/kg). Six normal pigs were included. An oral glucose tolerance test (OGTT) (n = 43) and insulin secretion test (n = 30) were performed and pancreata obtained for stereological determination of beta-cell mass. During OGTT, fasting glucose (r(2) = 0.1744, P < 0.01), area under the curve for glucose (r(2) = 0.2706, P < 0.001), maximum insulin secretion (r(2) = 0.2160, P < 0.01), and maximum C-peptide secretion (r(2) = 0.1992, P < 0.01) correlated with beta-cell mass. During the insulin secretion test, acute insulin response to 0.3 g/kg (r(2) = 0.6155, P < 0.0001) and 0.6 g/kg glucose (r(2) = 0.7321, P < 0.0001) and arginine (67 mg/kg) (r(2) = 0.7732, P < 0.0001) and maximum insulin secretion (r(2) = 0.8192, P < 0.0001) correlated with beta-cell mass. This study supports the use of functional tests to evaluate beta-cell mass in vivo and has established a validated basis for developing a mathematical method for estimation of beta-cell mass in vivo in the Göttingen minipig. PMID:12502501

Larsen, Marianne O; Rolin, Bidda; Wilken, Michael; Carr, Richard D; Gotfredsen, Carsten F

2003-01-01

324

Glucose sensor with a Sagnac interference optical system.  

Science.gov (United States)

The angle of optical rotation was measured by detecting the phase difference between clockwise and counterclockwise circular polarized light that propagated in a sensing loop. This polarimeter, or glucose sensor, consisted of a Sagnac interference optical system with a polarization-maintaining optical fiber, so it was not affected by the control limitations of the polarization rotation angle or the optical power fluctuation that occurs with scattered light, reflection, or polarization rotation in an optical system. The angle of rotation was measured from the phase difference of the glucose sensor when the concentration of glucose was changed. We confirmed that the resolution of optical rotation was 5×10(-4)??deg, and the resolution of the glucose concentration was 1??mg/dl accordingly. The measured specific rotation of glucose was mostly equal to a physical property value. One applications of this glucose sensor is in measuring the blood sugar levels of diabetic patients. PMID:24514189

Kumagai, Tatsuya; Tottori, Yusaku; Miyata, Ryusuke; Kajioka, Hiroshi

2014-02-01

325

Astragalus polysaccharides alleviates glucose toxicity and restores glucose homeostasis in diabetic states via activation of AMPK  

Science.gov (United States)

Aim: To establish the mechanism underlying the improvement of glucose toxicity by Astragalus polysaccharide (APS), which occurred via an AMP activated protein kinase (AMPK)-dependent pathway. Methods: In vivo and in vitro effects of APS on glucose homeostasis were examined in a type 2 diabetes mellitus (T2DM) rat model. The T2DM rat model was duplicated by a high-fat diet (58% fat, 25.6% carbohydrate, and 16.4% protein) and a small dose of streptozotocin (STZ, 25 mg/kg, ip). After APS therapy (700 mg·kg?1·d?1, ig) for 8 weeks, blood glucose, glycosylated hemoglobin, and serum insulin were measured. Insulin sensitivity was evaluated by the comprehensive analysis of oral glucose tolerance tests (OGTT) and HOMA IR index. Hepatic glycogen was observed by the PAS staining method. The expression and activity of skeletal muscle AMPK? and acetyl-CoA carboxylase (ACC), and the phosphorylation of hepatic glycogen synthase (GS), the glycogen synthase (GS),were measured by Western blotting. Glucose uptake was measured with the 2-deoxy-[3H]-D-glucose method in C2C12 cells. Results: The hyperglycemia status, insulin sensitivity, glucose uptake, and activation level of AMPK in diabetic rats were improved in response to APS administration. APS could also alleviate glucose toxicity in cultured mouse cells by the activation of AMPK. Conclusion: APS can alleviate glucose toxicity by increasing liver glycogen synthesis and skeletal muscle glucose translocation in the T2DM rat model, via activation of AMPK. PMID:19960007

Zou, Feng; Mao, Xian-qing; Wang, Nian; Liu, Jian; Ou-Yang, Jing-ping

2009-01-01

326

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Living WIth Type 2 Diabetes Program We Can Help Center for Information and Community Support Legal Assistance ... and then treating high blood glucose early will help you avoid problems associated with hyperglycemia. How Do ...

327

Recombinant glucose uptake system  

Science.gov (United States)

Recombinant organisms are disclosed that contain a pathway for glucose uptake other than the pathway normally utilized by the host cell. In particular, the host cell is one in which glucose transport into the cell normally is coupled to PEP production. This host cell is transformed so that it uses an alternative pathway for glucose transport that is not coupled to PEP production. In a preferred embodiment, the host cell is a bacterium other than Z. mobilis that has been transformed to contain the glf and glk genes of Z. mobilis. By uncoupling glucose transport into the cell from PEP utilization, more PEP is produced for synthesis of products of commercial importance from a given quantity of biomass supplied to the host cells.

Ingrahm, Lonnie O. (Gainesville, FL); Snoep, Jacob L. (Groede, NL); Arfman, Nico (Delft, NL)

1997-01-01

328

Hyperglycemia (High Blood Glucose)  

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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 ...

329

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy 8 Tips for Caregivers Health Insurance Health ... glucose happens when the body has too little insulin or when the body can't use insulin ...

330

Hyperglycemia (High Blood Glucose)  

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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 & ...

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Hyperglycemia (High Blood Glucose)  

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Full Text Available ... stress, such as family conflicts or school or dating problems. You may have experienced the dawn phenomenon ( ... glucose level. Cutting down on the amount of food you eat might also help. Work with your ...

332

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online Community ... Page Text Size: A A A Listen En Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical ...

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Hyperglycemia (High Blood Glucose)  

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Full Text Available ... for you to lower your blood glucose level. Cutting down on the amount of food you eat ... Are Careers Contact Us Policies Corporate Support Newsroom Press Releases For Professionals En Español Online Community Walk ...

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Hyperglycemia (High Blood Glucose)  

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Full Text Available ... the body can't use insulin properly. What Causes Hyperglycemia? A number of things can cause hyperglycemia: ... treating high blood glucose early will help you avoid problems associated with hyperglycemia. How Do I Treat ...

335

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... Monthly In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online ... Print Page Text Size: A A A Listen En Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the ...

336

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... Discrimination School Discrimination For Lawyers Complications Hypoglycemia Hyperglycemia Skin Complications Eye Complications Neuropathy Foot Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Treatment & Care Blood Glucose ...

337

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... A A A Listen En Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical term for high ... Advocacy Priorities News & Events National Youth Advocate The Cost of Diabetes Advocate Toolkit Call to Congress Research & ...

338

Hyperglycemia (High Blood Glucose)  

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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 & ...

339

Hyperglycemia (High Blood Glucose)  

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Full Text Available ... glucose) Dawn Phenomenon Checking for Ketones Tight Diabetes Control donate en -- Cherish their Memory - 2014-sept-donation- ... 2 Diabetes program. sticky en -- 2014 Oct Carb Control Cookbook - 2014-oct-carb-control.html More from ...

340

Predicting Plasma Glucose From Interstitial Glucose Observations Using Bayesian Methods  

DEFF Research Database (Denmark)

One way of constructing a control algorithm for an artificial pancreas is to identify a model capable of predicting plasma glucose (PG) from interstitial glucose (IG) observations. Stochastic differential equations (SDEs) make it possible to account both for the unknown influence of the continuous glucose monitor (CGM) and for unknown physiological influences. Combined with prior knowledge about the measurement devices, this approach can be used to obtain a robust predictive model. A stochastic-differential-equation-based gray box (SDE-GB) model is formulated on the basis of an identifiable physiological model of the glucoregulatory system for type 1 diabetes mellitus (T1DM) patients. A Bayesian method is used to estimate robust parameters from clinical data. The models are then used to predict PG from IG observations from 2 separate study occasions on the same patient. First, all statistically significant diffusion terms of the model are identified using likelihood ratio tests, yielding inclusion of ?Isc, ?Gp, and ?Gsc . Second, estimates using maximum likelihood are obtained, but prediction capability is poor. Finally a Bayesian method is implemented. Using this method the identified models are able to predict PG using only IG observations. These predictions are assessed visually. We are also able to validate these estimates on a separate data set from the same patient. This study shows that SDE-GBs and a Bayesian method can be used to identify a reliable model for prediction of PG using IG observations obtained with a CGM. The model could eventually be used in an artificial pancreas.

Hansen, Alexander Hildenbrand; Duun-Henriksen, Anne Katrine

2014-01-01

 
 
 
 
341

Human insulin A-chain peptide analog(s) with in vitro biological activity.  

Science.gov (United States)

In a previous study, we showed that a synthetic human insulin 1-chain analog, named analog (3) was capable of mimicking in vitro effects of native insulin, including stimulation of cell proliferation, glucose uptake and glycogen synthesis. Here, we have synthesized three new analogs (6, 9, 12) of the human A-chain, bearing or not their N- or C-terminal residue, to determine the structural features which are responsible for their biological properties. In vitro experiments clearly demonstrated that the N-terminal part of the peptides is required for the biological activity of the molecules, suggesting its crucial role in the mechanism underlying the cellular effect. Our findings may help to better understand the mechanism of interaction between insulin and its receptor. In addition, the present data demonstrate that some mini-insulin derived from the A-chain can exert similar effects as native insulin. These small peptides may offer specific advantages over insulin in the definition of new strategies for diabetes treatment. PMID:19618407

Le Flem, Guillaume; Pecher, Julien; Le Flem-Bonhomme, Valerie; Withdrawn, Author; Rochette, Jacques; Pujol, Jean-Pierre; Bogdanowicz, Patrick

2009-08-01

342

Facilitating the Spontaneous Generation of Analogies in Problem Solving.  

Science.gov (United States)

This paper examines whether an experimental treatment that encourages generativity and meaningful encoding can facilitate spontaneous analogical thinking, measuring the spontaneous generation of a relevant analog in solving a problem rather than the amount of factual material learned. Sixty-eight undergraduate students participated by reading the…

Cole, Peggy; Wilson, Brent G.

343

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

344

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

345

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

Science.gov (United States)

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 capillary and venous glucose concentrations with the diagnostic cut-off limits proposed by the World Health Organization (WHO) in 1999 was evaluated. Capillary glucose concentrations were consistently higher than venous glucose concentrations at all time points of the OGTT (p < 0.001), and the correlations between the measurements were statistically highly significant (p < 0.001). The differences between the samples were greatest in the non-fasting state as revealed by the 95% prediction intervals (mmol/L) in Bland-Altman plots; ± 0.54 at 0 min, ± 2.01 at 30 min, and ± 1.35 at 120 min. Equivalence values for capillary plasma glucose concentrations derived from this study tended to be higher than those proposed by the WHO as diagnostic cut-off limits. Stratifying subjects by glucose tolerance status according to the WHO criteria revealed disagreements related to glucose values close to the diagnostic cut-off points. The study findings highlight the uncertainty associated with derived equivalence values. However, capillary plasma glucose measurements could be suitable for diagnostic purposes in epidemiological studies and when translating results on a group basis. PMID:21961814

Ignell, Claes; Berntorp, Kerstin

2011-12-01

346

Erythropoietin and analogs.  

Science.gov (United States)

Erythropoietin (EPO), a glycoprotein hormone, stimulates the growth of red blood cells and as a consequence it increases tissue oxygenation. This performance enhancing effect is responsible for the ban of erythropioetin in sports since 1990. Especially its recombinant synthesis led to the abuse of this hormone, predominatly in endurance sports. The analytical differentiation of endogenously produced erythropoietin from its recombinant counterpart by using isoelectric focusing and double blotting is a milestone in the detection of doping with recombinant erythropoietin. However, various analogous of the initial recombinant products, not always easily detectable by the standard IEF-method, necessitate the development of analytical alternatives for the detection of EPO doping. The following chapter summarizes its mode of action, the various forms of recombinant erythropoietin, the main analytical procedures and strategies for the detection of EPO doping as well as a typical case report. PMID:20020369

Reichel, Christian; Gmeiner, Günter

2010-01-01

347

Analog safety data link  

International Nuclear Information System (INIS)

An analog data link has been developed which is designed to protect the control room personnel and equipment from high voltage faults of up to 20 KV. This data link is designed to be used with balanced lines and has a dc-1MH bandwidth, 60 dB dynamic range and a high common mode rejection ratio. Each channel of the system consists of a high voltage fuse and spark gap assembly designed to open the circuit between the input connector and the rest of the system. Following this there is a-20dB attenuator which will limit the output voltage in case of a failure in the spark gap. The attenuator will also draw enough current to open the fuse. Finally, there is a + 21 dB gain amplifier to boast the signal back to its original level and to drive the 120 ? lines to the control room

348

The Impact of Melatonin on Glucose Homeostasis  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: Melatonin is a pineal product mainly charged with the maintenance of antioxidant conditions in human. This study is performed to identify the short-term effect of melatonin on glucose homeostasis in diabetic patients. Materials and Methods: Melatonin and placebo were given perorally to sixty patients. Blood glucose and insulin levels were measured with constant intervals. Results: No significant correlation was found among the levels of glucose, insulin and HOMA-IR index at any time after melatonin/placebo administration.Conclusions: Prospective studies with long-term use of melatonin are needed to define the exact role of melatonin in glucose homeostasis. Turk Jem 2009; 13: 52-5

Zeynep Arzu Ye?in

2009-12-01

349

Boron analogs of ?-amino acids  

International Nuclear Information System (INIS)

The authors have been concerned with the synthesis, characterization, and definition of a class of novel isoelectronic and isostructural boron analogs of the ?-amino acids, glycine, alanine and betaine. This paper presents a brief review of the preparation and characterization of some of the first examples of the analogs and related compounds and describes their antitumor activity. The results of preliminary testing at Brookhaven as to the suitability of these analogs for use in BNCT are presented

350

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

351

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

352

Analogical Modeling and Quantum Computing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

353

Multivariate image processing technique for noninvasive glucose sensing  

Science.gov (United States)

A potential noninvasive glucose sensing technique was investigated for application towards in vivo glucose monitoring for individuals afflicted with diabetes mellitus. Three dimensional ray tracing simulations using a realistic iris pattern integrated into an advanced human eye model are reported for physiological glucose concentrations ranging between 0 to 500 mg/dL. The anterior chamber of the human eye contains a clear fluid known as the aqueous humor. The optical refractive index of the aqueous humor varies on the order of 1.5x10-4 for a change in glucose concentration of 100 mg/dL. The simulation data was analyzed with a developed multivariate chemometrics procedure that utilizes iris-based images to form a calibration model. Results from these simulations show considerable potential for use of the developed method in the prediction of glucose. For further demonstration, an in vitro eye model was developed to validate the computer based modeling technique. In these experiments, a realistic iris pattern was placed in an analog eye model in which the glucose concentration within the fluid representing the aqueous humor was varied. A series of high resolution digital images were acquired using an optical imaging system. These images were then used to form an in vitro calibration model utilizing the same multivariate chemometric technique demonstrated in the 3-D optical simulations. In general, the developed method exhibits considerable applicability towards its use as an in vivo platform for the noninvasive monitoring of physiological glucose concentration.

Webb, Anthony J.; Cameron, Brent D.

2010-02-01

354

Glutamate mediates acute glucose transport inhibition in hippocampal neurons.  

Science.gov (United States)

Although it is known that brain activity is fueled by glucose, the identity of the cell type that preferentially metabolizes the sugar remains elusive. To address this question, glucose uptake was studied simultaneously in cultured hippocampal neurons and neighboring astrocytes using a real-time assay based on confocal epifluorescence microscopy and fluorescent glucose analogs. Glutamate, although stimulating glucose transport in astrocytes, strongly inhibited glucose transport in neurons, producing in few seconds a 12-fold increase in the ratio of astrocytic-to-neuronal uptake rate. Neuronal transport inhibition was reversible on removal of the neurotransmitter and displayed an IC50 of 5 microm, suggesting its occurrence at physiological glutamate concentrations. The phenomenon was abolished by CNQX and mimicked by AMPA, demonstrating a role for the cognate subset of ionotropic glutamate receptors. Transport inhibition required extracellular sodium and calcium and was mimicked by veratridine but not by membrane depolarization with high K+ or by calcium overloading with ionomycin. Therefore, glutamate inhibits glucose transport via AMPA receptor-mediated sodium entry, whereas calcium entry plays a permissive role. This phenomenon suggests that glutamate redistributes glucose toward astrocytes and away from neurons and represents a novel molecular mechanism that may be important for functional imaging of the brain using positron emission tomography. PMID:15509754

Porras, Omar H; Loaiza, Anitsi; Barros, L Felipe

2004-10-27

355

Sorbitol inhibition of glucose metabolism by Streptococcus sanguis 160.  

Science.gov (United States)

Clinical studies in Sweden have shown that the proportion of sorbitol-utilizing strains of Streptococcus sanguis increases in dental plaque from individuals using sorbitol-containing products for prolonged periods. We have undertaken to study the metabolism of glucose and sorbitol by S. sanguis 160, isolated from a subject consuming sorbitol-containing chewing-gum 4 times a day for 4 years. Growth on glucose was inhibited by the presence of sorbitol in the growth medium and sorbitol was utilized in the presence of glucose, albeit, at a slower rate than glucose. In addition, pulses of glucose added to cultures growing on sorbitol resulted in the expulsion of sorbitol from the cell. In order to examine further the relationship of sorbitol and glucose, uptake assays were carried out with S. sanguis 160 grown in continuous culture (pH 7.0, dilution rate = 0.1 h-1) with glucose, sorbitol or nitrogen (sorbitol excess) limitations. The uptake of [14C]-glucose by sorbitol-limited cells, but not by glucose-limited cells, was inhibited by sorbitol, as was glycolysis. Kinetic experiments with glucose-limited cells showed 2 transport systems for glucose with Ks values of 5.2 and 40 microM, and glucose phosphorylation activity by decryptified cells indicated transport by the P-enolpyruvate (PEP) phosphotransferase system (PTS) with lesser activity for an ATP-dependent transport process. Transition from glucose-limited growth to sorbitol-limited growth revealed repression of total [14C]-glucose uptake by intact cells and activity for Enzyme II for glucose (Ellglc) of the PTS measured in membrane preparations in the presence of an excess of the soluble PTS proteins in crude cell-free supernatant fractions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1945498

Hamilton, I R; Svensater, G

1991-06-01

356

An adaptive plasma glucose controller based on a nonlinear insulin/glucose model.  

Science.gov (United States)

The design of plasma glucose controllers traditionally relies on linear approaches. The implementation of an appropriate nonlinear model of the insulin/glucose regulatory system into an adaptive controller should predict the insulin-dependent glucose removal more reliably and hence provide better control over a wide spectrum of insulin signals. A discretized form of the model leads to a two-step procedure. First, the measured plasma glucose levels associated with the exogenous glucose infusion rates are used in the estimation of the past removal rates which, in turn, can be expressed as a weighted sum of past insulin inputs and previous values of the removal rate. Parameters of the sum are adjusted on-line by a recursive method of estimation which features a prefiltering of data to account for a corrupting coloured process noise. The same equation is in turn used to predict the time course of the insulin-dependent fractional rate of glucose removal. The performance of the controller, tested in vivo in three pigs, is presented for various intravenous or subcutaneous rapid injections and staircase infusions of insulin. Plasma glucose is maintained at an average level of 99.9 +/- 8.7% of the target value (% set point +/- coefficient of variation). The controller reacts promptly to large and rapid variations in insulin action. Although control improves with the number of glucose measurements, the prediction of glucose removal allows for some flexibility in the monitoring of the plasma glucose. Sampling frequency varied from a 2 min interval during transient periods to 7 min as steady states were reached. PMID:8026845

Candas, B; Radziuk, J

1994-02-01

357

Specific absorption rate levels measured in a phantom head exposed to radio frequency transmissions from analog hand-held mobile phones  

Energy Technology Data Exchange (ETDEWEB)

Electric fields (E-fields) induced within a phantom head from exposure to three different advanced mobile phone system (AMPS) hand-held telephones were measured using an implantable E-Field probe. Measurements were taken in the eye nearest the phone and along a lateral scan through the brain from its center to the side nearest the phone. During measurement, the phones were positioned alongside the phantom head as in typical use and were configured to transmit at maximum power (600 mW nominal). The specific absorption rate (SAR) was calculated from the in situ E-field measurements, which varied significantly between phone models and antenna configuration. The SARs induced in the eye ranged from 0.007 to 0.21 W/kg. Metal-framed spectacles enhanced SAR levels in the eye by 9--29%. In the brain, maximum levels were recorded at the measurement point closest to the phone and ranged from 0.12 to 0.83 W/kg. These SARs are below peak spatial limits recommended in the US and Australian national standards and the IRPA guidelines for safe exposure to radio frequency (RF) electromagnetic fields. Furthermore, a detailed thermal analysis of the eye indicated only a 0.022 C maximum steady-state temperature rise in the eye from a uniform SAR loading of 0.21 W/kg. A more approximate thermal analysis in the brain also indicated only a small maximum temperature rise of 0.034 C for a local SAR loading of 0.83 W/kg.

Anderson, V.; Joyner, K.H. [Telecom Research Labs., Clayton, Victoria (Australia). Electromagnetic Compatibility Section

1995-05-01

358

Specific absorption rate levels measured in a phantom head exposed to radio frequency transmissions from analog hand-held mobile phones.  

Science.gov (United States)

Electric fields (E-fields) induced within a phantom head from exposure to three different advanced mobile phone system (AMPS) hand-held telephones were measured using an implantable E-field probe. Measurements were taken in the eye nearest the phone and along a lateral scan through the brain from its centre to the side nearest the phone. During measurement, the phones were positioned alongside the phantom head as in typical use and were configured to transmit at maximum power (600 mW nominal). The specific absorption rate (SAR) was calculated from the in situ E-field measurements, which varied significantly between phone models and antenna configuration. The SARs induced in the eye ranged from 0.007 to 0.21 W/kg. Metal-framed spectacles enhanced SAR levels in the eye by 9-29%. In the brain, maximum levels were recorded at the measurement point closest to the phone and ranged from 0.12 to 0.83 W/kg. These SARs are below peak spatial limits recommended in the U.S. and Australian national standards [IEEE Standards Coordinating Committee 28 (1991): C95.1-1991 and Standards Australia (1990): AS2772.1-1990] and the IRPA guidelines for safe exposure to radio frequency (RF) electromagnetic fields [IRPA (1988): Health Phys 54:115-123]. Furthermore, a detailed thermal analysis of the eye indicated only a 0.022 degrees C maximum steady-state temperature rise in the eye from a uniform SAR loading of 0.21 W/kg. A more approximate thermal analysis in the brain also indicated only a small maximum temperature rise of 0.034 degrees C for a local SAR loading of 0.83 W/kg. PMID:7748204

Anderson, V; Joyner, K H

1995-01-01

359

Contraction-induced [18F]-fluoro-deoxy-glucose uptake can be measured in human calf muscle using high-resolution PET.  

Science.gov (United States)

Contraction-induced glucose uptake can be imaged and quantified by the use of positron emission tomography (PET). In the human extremities, such data may reveal important information regarding the in vivo mechanical function of e.g. the force transmitting tissues such as tendons. However, to investigate structures of limited size, a PET scanner with high resolution is required. We tested the potential of the recently developed high-resolution brain PET scanner (ECAT HRRT) for imaging of human lower extremities. [18F]-fluoro-deoxy-glucose uptake following voluntary and stimulated isometric muscle contractions was studied in a 30-year-old male. The results showed that the activated muscle or muscles are clearly delineated in the high-resolution PET images. Furthermore, the load-induced gain in tendon uptake was clearly visualized. In conclusion, the HRRT scanner is an appropriate tool for investigating physiological processes within the human extremities, and the very high resolution yields a potential for more accurate conclusions when target tissues are limited in size. PMID:17564673

Kalliokoski, Kari K; Bojsen-Møller, Jens; Seppänen, Marko; Johansson, Jarkko; Kjaer, Michael; Teräs, Mika; Magnusson, S Peter

2007-07-01

360

Error in the measurement of the Telector monitor, model 6112B (analogic); Error de medicion del monitor Telector, modelo 6112B (analogico)  

Energy Technology Data Exchange (ETDEWEB)

This monitor is a portable equipment used with radiological protection ends in many areas where use of radioactive material is made, since account with a telescopic bar with two Geiger Mueller tubes (GM) to measure gamma radiation. The maker in his specifications indicates that the equipment is able to measure from 0.1 R/hr up to 1000 R/hr and their response doesn't depend on the energy in the interval of 300 keV to 3 MeV. However, personal of the Electronic Systems department carrying out tests in the Secondary Laboratory of Dosimetric Calibration (LSCD) of the ININ, it found that this monitor really presents an energy dependence for the energies of {sup 60}Co, in the scale of 2 R/hr. With base in an analysis of the equipment and the two GM detectors that it uses, was found that the origin of the problem is the point of saturation of the detector that uses for this scale, which coincides with the maximum measurement value that is of 2 R/hr. This flaw it can be solved using the detector that operates with the high scales, for which is required to make a modification to the electronic circuit in the part of the switch that selects the detector type. (Author)

Cruz E, P.; Sanchez R, G.H.; Torres B, M.A.; Martinez, R.F. [ININ, 52750 La Marquesa, Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: pce@nuclear.inin.mx

2007-07-01

 
 
 
 
361

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

362

Transport of glucose and mannose by a common phosphoenolpyruvate-dependent phosphotransferase system in Streptococcus mutans GS5.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Decryptified cells of Streptococcus mutans GS5 transport glucose, mannose, and fructose by constitutive phosphoenolpyruvate-dependent phosphotransferase systems (PTSs). Although the non-metabolizable glucose analog 2-deoxyglucose is transported by a PTS, alpha-methylglucose is not taken up by strain GS5. The transport of [14C]mannose and [14C]glucose was almost totally blocked by the heterologous sugars, indicating that these substrates may share a common PTS permease. [14C]fructose transport...

Liberman, E. S.; Bleiweis, A. S.

1984-01-01

363

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

364

Natural analog studies: Licensing perspective  

International Nuclear Information System (INIS)

This report describes the licensing perspective of the term open-quotes natural analog studiesclose 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

365

Adaptive blood glucose control for intensive care applications.  

Science.gov (United States)

Control of blood glucose concentration for patients in intensive care units (ICUs) has been demonstrated to be beneficial in reducing mortality and the incidence of serious complications, for both diabetic and non-diabetic patients. However, the high degree of variability and uncertainty characterizing the physiological conditions of critically ill subjects makes automated glucose control quite difficult; consequently, traditional, nurse-implemented protocols are widely employed. These protocols are based on infrequent glucose measurements, look-up tables to determine the appropriate insulin infusion rates, and bedside insulin administration. In this paper, a novel automatic adaptive control strategy based on frequent glucose measurements and a self-tuning control technique is validated based on a simulation study for 200 virtual patients. The adaptive control strategy is shown to be highly effective in controlling blood glucose concentration despite the large degree of variability in the blood glucose response exhibited by the 200 simulated patients. PMID:22424730

Ottavian, Matteo; Barolo, Massimiliano; Zisser, Howard; Dassau, Eyal; Seborg, Dale E

2013-02-01

366

Parking Structures: Fuss Analogs  

CERN Document Server

For any irreducible real reflection group $W$ with Coxeter number $h$, Armstrong, Reiner, and the author introduced a pair of $W \\times \\ZZ_h$-modules which deserve to be called {\\sf $W$-parking spaces} which generalize the type A notion of parking functions and conjectured a relationship between them. In this paper we give a Fuss analog of their constructions. For a Fuss parameter $k \\geq 1$, we define a pair of $W \\times \\ZZ_{kh}$-modules which deserve to be called {\\sf $k$-$W$-parking spaces} and conjecture a relationship between them. We prove the weakest version of our conjectures for each of the infinite families ABCDI of finite reflection groups, together with proofs of stronger versions in special cases. Whenever our weakest conjecture holds for $W$, we have the following corollaries. First, there is a simple formula for the character of either $k$-$W$-parking space. Second, we recover a cyclic sieving result due to Krattenthaler and M\\"uller which gives the cycle structure of a generalized rotation a...

Rhoades, Brendon

2012-01-01

367

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

368

Evaluation of enzyme-based tear glucose electrochemical sensors over a wide range of blood glucose concentrations.  

Science.gov (United States)

Miniature enzyme-based amperometric and coulometric glucose sensors were fabricated and applied to measure tear glucose concentrations in anesthetized rabbits. Without perturbing the eyeball, 3 µL of tear fluid was sampled from the marginal conjunctiva under the lower eyelid of anesthetized rabbits at various time points via a microliter glass capillary tube, and the miniature sensors were then inserted into the volume of collected tear fluids within the capillaries for detection. Intravenous bolus doses of insulin were administrated to the rabbits to lower the elevated blood glucose concentrations caused by anesthesia over the 7h test periods. A significant correlation was found between tear and blood glucose levels for multiple rabbits, suggesting that electrochemical sensor-based tear glucose measurements may be a potential supplementary method for point-of-care glucose monitoring. PMID:23747996

Peng, Bo; Lu, Jing; Balijepalli, Anant S; Major, Terry C; Cohan, Bruce E; Meyerhoff, Mark E

2013-11-15

369

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

370

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

371

The synthesis of analogs of shuangkangsu, a novel natural cycloperoxide glucoside from Lonicera japonica Thunb.  

Science.gov (United States)

Four novel optically pure cycloperoxide glucosides 9a, 9b, 10a, and 10b, analogs of shuangkangsu--a natural product with unusual skeleton and antivirus activity from the buds of Lonicera japonica Thunb, were firstly synthesized by employing peroxidation and glucosidation reactions from phthalaldehyde or 4,5-dichloro phthalaldehyde and glucose. PMID:19219731

Tang, Yan-Bo; Huang, Long-Jiang; Li, Di-Zao; Zhang, Qing-Jian; Chen, Ruo-Yun; Yu, De-Quan

2009-01-01

372

Glucose-6-phosphatase deficiency.  

Science.gov (United States)

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. PMID:21599942

Froissart, Roseline; Piraud, Monique; Boudjemline, Alix Mollet; Vianey-Saban, Christine; Petit, François; Hubert-Buron, Aurélie; Eberschweiler, Pascale Trioche; Gajdos, Vincent; Labrune, Philippe

2011-01-01

373

Analog-to-digital conversion  

CERN Document Server

The design of an analog-to-digital converter or digital-to-analog converter is one of the most fascinating tasks in micro-electronics. In a converter the analog world with all its intricacies meets the realm of the formal digital abstraction. Both disciplines must be understood for an optimum conversion solution. In a converter also system challenges meet technology opportunities. Modern systems rely on analog-to-digital converters as an essential part of the complex chain to access the physical world. And processors need the ultimate performance of digital-to-analog converters to present the results of their complex algorithms. The same progress in CMOS technology that enables these VLSI digital systems creates new challenges for analog-to-digital converters: lower signal swings, less power and variability issues. Last but not least, the analog-to-digital converter must follow the cost reduction trend. These changing boundary conditions require micro-electronics engineers to consider their design choices for...

Pelgrom, Marcel J M

2010-01-01

374

Glucose Regulates the Expression of the Apolipoprotein A5 Gene  

Energy Technology Data Exchange (ETDEWEB)

The apolipoprotein A5 gene (APOA5) is a key player in determining triglyceride concentrations in humans and mice. Since diabetes is often associated with hypertriglyceridemia, this study explores whether APOA5 gene expression is regulated by alteration in glucose homeostasis and the related pathways. D-glucose activates APOA5 gene expression in a time- and dose-dependent manner in hepatocytes, and the glycolytic pathway involved was determined using D-glucose analogs and metabolites. Together, transient transfections, electrophoretic mobility shift assays and chromatin immunoprecipitation assays show that this regulation occurs at the transcriptional level through an increase of USF1/2 binding to an E-box in the APOA5 promoter. We show that this phenomenon is not due to an increase of mRNA or protein expression levels of USF. Using protein phosphatases 1 and 2A inhibitor, we demonstrate that D-glucose regulates APOA5 gene via a dephosphorylation mechanism, thereby resulting in an enhanced USF1/2-promoter binding. Last, subsequent suppressions of USF1/2 and phosphatases mRNA through siRNA gene silencing abolished the regulation. We demonstrate that APOA5 gene is up regulated by D-glucose and USF through phosphatase activation. These findings may provide a new cross talk between glucose and lipid metabolism.

Fruchart, Jamila; Nowak, Maxime; Helleboid-Chapman, Audrey; Jakel, Heidelinde; Moitrot, Emmanuelle; Rommens, Corinne; Pennacchio, Len A.; Fruchart-Najib, Jamila; Fruchart, Jean-Charles

2008-04-07

375

Electrical Analogy to an Atomic Force Microscope  

Directory of Open Access Journals (Sweden)

Full Text Available Several applications of the atomic force microscopy (AFM, such as measurement of soft samples, manipulation with molecules, etc., require mechanical analysis of the AFM probe behavior. In this article we suggest the electrical circuit analogy to AFM cantilever tip motion. Well developed circuit theories in connection with fairly accessible software for circuit analysis make this alternative method easy to use for a wide community of AFM users.

O. Kucera

2010-04-01

376

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

377

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

378

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 ... your doctor may change the amount of your medication or insulin or possibly the timing of when you take it. What if it ... $('.survey-form .form-group .survey-alert-wrap'). ...

379

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Cure Father of the Year Stop Diabetes at School Tour de Cure Women's Series Rip's B.A.D. Ride Do-It-Yourself Fundraising Close www.diabetes.org > Living With Diabetes > Treatment and Care > Blood Glucose Testing Share: Print Page Text Size: ...

380

¿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