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1

Examining glucose transport in single vascular smooth muscle cells with a fluorescent glucose analog.  

Science.gov (United States)

Changes in vascular smooth muscle glucose transport are thought to contribute to the pathogenesis of vascular disease in conditions such as diabetes, yet no single-cell assay for glucose uptake by VSM exists. Therefore, we examined the uptake of the fluorescent glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) in isolated pig vascular smooth muscle cells (VSMC) using digital imaging microscopy. Uptake of 2-NBDG by VSMC was inhibited by D-glucose but not by L-glucose, suggesting that 2-NBDG enters VSMC via glucose transporters. Uptake of 2-NBDG was linear in the presence of 10 mM D-glucose (n=6, R2=0.9408) but not in its absence (n=4, R2=0.9993), indicating that 2-NBDG is not metabolized and accumulates within the cells. 2-NBDG fluorescence in VSMC was often non-uniform and appeared to represent binding of 2-NBDG to some cytoplasmic component. The present study demonstrates that 2-NBDG is a useful tool for examining vascular smooth muscle glucose uptake at the single cell level. PMID:10783904

Lloyd, P G; Hardin, C D; Sturek, M

1999-01-01

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

An Analysis of How to Measure Glucose during Glucose Clamps: Are Glucose Meters Ready for Research?  

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This article provides a perspective on the challenges of appropriate glucose measurement in the context of glucose clamp experiments. In a first step, the core outcome parameters of a clamp experiment, the blood glucose target level, and the glucose infusion rate will be identified. The relation of these core parameters to glucose measurement are discussed. From there, the core quality parameters of glucose measurement within a clinical research setting are identified and assessed in light of...

Hompesch, Marcus; Rave, Klaus

2008-01-01

4

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

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

1982-09-02

6

Potent humanin analog increases glucose-stimulated insulin secretion through enhanced metabolism in the ? cell.  

Science.gov (United States)

Humanin (HN) is a 24-aa polypeptide that offers protection from Alzheimer's disease and myocardial infarction, increases insulin sensitivity, improves survival of ? cells, and delays onset of diabetes. Here we examined the acute effects of HN on insulin secretion and potential mechanisms through which they are mediated. Effects of a potent HN analog, HNGF6A, on glucose-stimulated insulin secretion (GSIS) were assessed in vivo and in isolated pancreatic islets and cultured murine ? cell line (?TC3) in vitro. Sprague-Dawley rats (3 mo old) that received HNGF6A required a significantly higher glucose infusion rate and demonstrated higher insulin levels during hyperglycemic clamps compared to saline controls. In vitro, compared to scrambled peptide controls, HNGF6A increased GSIS in isolated islets from both normal and diabetic mice as well as in ?TC3 cells. Effects of HNGF6A on GSIS were dose dependent, K-ATP channel independent, and associated with enhanced glucose metabolism. These findings demonstrate that HNGF6A increases GSIS in whole animals, from isolated islets and from cells in culture, which suggests a direct effect on the ? cell. The glucose-dependent effects on insulin secretion along with the established effects on insulin action suggest potential for HN and its analogs in the treatment of diabetes. PMID:23995290

Kuliawat, Regina; Klein, Laura; Gong, Zhenwei; Nicoletta-Gentile, Marianna; Nemkal, Anjana; Cui, Lingguang; Bastie, Claire; Su, Kai; Huffman, Derek; Surana, Manju; Barzilai, Nir; Fleischer, Norman; Muzumdar, Radhika

2013-12-01

7

A new Michaelis–Menten-based kinetic model for transport and phosphorylation of glucose and its analogs in skeletal muscle  

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Purpose: A new model is introduced that individually resolves the delivery, transport, and phosphorylation steps of metabolism of glucose and its analogs in skeletal muscle by interpreting dynamic positron emission tomography (PET) data.Methods: The model uniquely utilizes information obtained from the competition between glucose and its radiolabeled analogs. Importantly, the model avoids use of a lumped constant which may depend on physiological state. Four basic physiologic quantities const...

Huang, Hsuan-ming; Ismail-beigi, Faramarz; Muzic, Raymond F.

2011-01-01

8

Computing Performance Measures for Inpatient Glucose Management  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent research indicates that inpatients with hyperglycemia suffer poor outcomes. Efforts to improve glycemic control need measures of performance. We proposed candidate measures, but these require analysis of large glucose datasets, a cumbersome task for individual institutions. We developed an application accessible over the internet that facilitates computation of these performance measures.

Thomas, Prem; Shiffman, Richard; Inzucchi, Silvio E.

2006-01-01

9

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

10

A review of metabolism of labeled glucoses for use in measuring glucose recycling  

International Nuclear Information System (INIS)

The fate of tritium from each carbon of D-glucose and the metabolism of L-glucose and 2-deoxy-D-glucose are known. Differences in metabolism of labeled glucoses can be used to quantify physical and chemical recycling of glucose. Only physical recycling is measured by [1-3H]-L-glucose, whereas [U-14C]-D-glucose measures total recycling. The difference between [1-3H]-L-glucose and [U-14C]-D-glucose, therefore, is chemical recycling. Recycling from extracellular binding sites and hepatic glucose 6-phosphate can be measured by difference between [1,2-3H]-2-deoxy-D-glucose and [1-3H]-L-glucose, and the difference in irreversible loss of the two will measure extrahepatic uptake of D-glucose. Recycling via Cori-alanine cycle plus CO2 is the difference in irreversible loss measured by using [6-3H]-glucose and [U-14C]-D-glucose. Recycling via the hexose monophosphate pathway can be determined by difference in irreversible loss between [1-3H]-D-glucose and [6-3H]-D-glucose. Recycling via CO2 and glycerol must be measured directly with [U-14C]glucose, bicarbonate, and glycerol. Recycling via hepatic glycogen can be estimated by subtracting all other measured chemical recycling from total chemical recycling. This review describes means to quantify glucose recycling in vivo, enabling studies of mechanisms for conservation and utilization of glucose. 54 references

1990-01-01

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-_1_4C]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

1982-01-01

12

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

1999-10-01

13

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

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

1975-10-20

15

Extraction of glucose information in blood glucose measurement by noninvasive near-infrared spectra  

Science.gov (United States)

Near infrared spectroscopy has been proposed as an effective way for measuring blood glucose non-invasively. However the change of spectrum due to an increase in glucose level is very small compared to the changes due to other variations such as absorption of major blood components, skin surface reflectance, temperature and pressure and so on. So the complexity of spectrum makes it difficult to identify unique glucose information. In this paper, the effect of background correction is discussed firstly. Then a simple substitution is proposed to compute the net analyte signal of glucose using the subspace spanned by the background spectra. For the in vitro experiment, the net analyte signals of glucose using the traditional methods and the subspace spanned by background have the same peaks in the absorption peaks of glucose for the glucose aqueous solution. For in vivo experiment, there is significant spectral difference between the subject who took OGTT test and the subject who took no glucose or water. And the net analyte signal of glucose is computed for OGTT test based on the subspace spanned by the spectra of subject who didn"t take glucose. Results show that, the spectral information induced by glucose taking is quite significant but it does not have the same peak at the absorption peak of glucose in near-infrared region.

Liu, Rong; Chen, Wenliang; Gu, Xiaoyu; Luo, Yunhan; Xu, Kexin

2005-03-01

16

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

1988-01-01

17

Enhancement of Biocontrol of Blue Mold with the Nutrient Analog 2-Deoxy-d-Glucose on Apples and Pears  

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The glucose analog, 2-deoxy-d-glucose (2-DOG) enhanced biocontrol of blue mold (caused by Penicillium expansum), the most important postharvest disease of apples and pears. 2-DOG strongly inhibited P. expansum, and of the two antagonists investigated, Pseudomonas syringae was resistant to 2-DOG at 10 mg/ml whereas Sporobolomyces roseus was susceptible. A mutant of S. roseus resistant to 2-DOG was developed. Addition of 2-DOG at 4 mg/ml allowed more than a 10-fold reduction in the concentratio...

Janisiewicz, W. J.

1994-01-01

18

Flow cytomeric measurement of DNA and incorporated nucleoside analogs  

Energy Technology Data Exchange (ETDEWEB)

A method is provided for simultaneously measuring total cellular DNA and incorporated nucleoside analog. The method entails altering the cellular DNA of cells grown in the presence of a nucleoside analog so that single stranded and double stranded portions are present. Separate stains are used against the two portions. An immunochemical stain is used against the single stranded portion to provide a measure of incorporated nucleoside analog, and a double strand DNA-specific stain is used against the double stranded portion to simultaneously provide a measure of total cellular DNA. The method permits rapid flow cytometric analysis of cell populations, rapid identification of cycling and noncycling subpopulations, and determination of the efficacy of S phase cytotoxic anticancer agents.

Dolbeare, Frank A. (Livermore, CA); Gray, Joe W. (Livermore, CA)

1989-01-01

19

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

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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 p...

2011-01-01

20

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

1985-01-01

 
 
 
 
21

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.

2014-01-01

22

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

International Nuclear Information System (INIS)

The phosphono analog of UDP-glucose (UDPG) has been synthesized as a first entry into potential dead-end inhibitors of glycosyltransferases using UDP-sugars such as UDP-glucuronyltransferase and possible alternative substrates for UDPG dehydrogenase and epimerase. 1-Deoxy-?-D-glucopyranosylmethanephosphonate (G-1-CH_2P) was synthesized by modifications of literature procedures and characterized by "1H, "3"1P and "1"3C NMR. Condensation of G-1-CH_2P with UMP morpholidate gave the expected phosphono analog of UDPG (UDPCH_2G) in low yield. G-1-CH_2P was found to be a substrate for UTP: glucose-1-phosphate pyrophosphoyrlase. Thus, UDPCH_2G can be prepared enzymatically from G-1-CH_2P and UTP by the coupled action of the pyrophosphoyrlase and inorganic pyrophosphatase. Preliminary evidence suggests UDPCH_2G is a very poor substrate for UDPG dehydrogenase. Thus, efficient enzymatic synthesis of the phosphono analog (UDPCH_2GA) of UDP-glucuronate appears unlikely

1987-05-01

23

Hamiltonian and measuring time for analog quantum search  

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We derive in this study a Hamiltonian to solve with certainty the analog quantum search problem analogue to the Grover algorithm. The general form of the initial state is considered. Since the evaluation of the measuring time for finding the marked state by probability of unity is crucially important in the problem, especially when the Bohr frequency is high, we then give the exact formula as a function of all given parameters for the measuring time.

Hsieh, Jin-yuan; Li, Che-ming; Chuu, Der-san

2002-01-01

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

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

International Nuclear Information System (INIS)

A new double-label autoradiographic glucose analog method for the sequential measurement of altered regional cerebral metabolic rates for glucose in the same animal is presented. This method is based on the sequential injection of two boluses of glucose tracer labeled with two different isotopes (short-lived 18F and long-lived 3H, respectively). An operational equation is derived which allows the determination of glucose utilization for the time period before the injection of the second tracer; this equation corrects for accumulation and loss of the first tracer from the metabolic pool occurring after the injection of the second tracer. An error analysis of this operational equation is performed. The double-label deoxyglucose method is validated in the primary somatosensory (''barrel'') cortex of the anesthetized rat. Two different rows of whiskers were stimulated sequentially in each rat; the two periods of stimulation were each preceded by an injection of glucose tracer. After decapitation, dried brain slices were first exposed, in direct contact, to standard X-ray film and then to uncoated, ''tritium-sensitive'' film. Results show that the double-label deoxyglucose method proposed in this paper allows the quantification and complete separation of glucose utilization patterns elicited by two different stimulations sequentially applied in the same animal. (author)

1987-01-01

26

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

Energy Technology Data Exchange (ETDEWEB)

A new double-label autoradiographic glucose analog method for the sequential measurement of altered regional cerebral metabolic rates for glucose in the same animal is presented. This method is based on the sequential injection of two boluses of glucose tracer labeled with two different isotopes (short-lived /sup 18/F and long-lived /sup 3/H, respectively). An operational equation is derived which allows the determination of glucose utilization for the time period before the injection of the second tracer; this equation corrects for accumulation and loss of the first tracer from the metabolic pool occurring after the injection of the second tracer. An error analysis of this operational equation is performed. The double-label deoxyglucose method is validated in the primary somatosensory (''barrel'') cortex of the anesthetized rat. Two different rows of whiskers were stimulated sequentially in each rat; the two periods of stimulation were each preceded by an injection of glucose tracer. After decapitation, dried brain slices were first exposed, in direct contact, to standard X-ray film and then to uncoated, ''tritium-sensitive'' film. Results show that the double-label deoxyglucose method proposed in this paper allows the quantification and complete separation of glucose utilization patterns elicited by two different stimulations sequentially applied in the same animal.

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

1987-08-01

27

Multiparameter Methods for Non-invasive Measurement of Blood Glucose  

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The standard determination of the blood glucose level involves finger-prick capillary measurements, which is uncomfortable and causes skin injury. Painless glycemic control would improve the quality of life of patients by increasing compliance. This thesis describes the technologies of bioimpedance and absorption spectroscopy applied to determine glucose characteristics in deionized water and blood. In sequence simulations helped to develop methods for transcutaneous glycemic measurements, wh...

Ferrante Do Amaral, Carlos Eduardo

2009-01-01

28

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

International Nuclear Information System (INIS)

Dihalogen derivates of D-glucal were formed by the direct addition of halogen to the unsaturated double-bond between C atoms 1 and 2 in D-glucal. _8_2Br-glucal and _3_6Cl-glucal were injected into the carotid artery of rats and brain uptake studied and compared with uptake for D-glucose and 2-deoxy-D-glucose. Investigations with enzymes have shown D-glucal dihalides to be good substrates for hexokinase. (U.K.)

1982-01-01

29

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

Science.gov (United States)

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

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

2011-12-01

30

AMPLITUDE AND TIME MEASUREMENT ASIC WITH ANALOG DERANDOMIZATION.  

Energy Technology Data Exchange (ETDEWEB)

We describe a new ASIC for accurate and efficient processing of high-rate pulse signals from highly segmented detectors. In contrast to conventional approaches, this circuit affords a dramatic reduction in data volume through the use of analog techniques (precision peak detectors and time-to-amplitude converters) together with fast arbitration and sequencing logic to concentrate the data before digitization. In operation the circuit functions like a data-driven analog first-in, first-out (FIFO) memory between the preamplifiers and the ADC. Peak amplitudes of pulses arriving at any one of the 32 inputs are sampled, stored, and queued for readout and digitization through a single output port. Hit timing, pulse risetime, and channel address are also available at the output. Prototype chips have been fabricated in 0.35 micron CMOS and tested. First results indicate proper functionality for pulses down to 30 ns peaking time and input rates up to 1.6 MHz/channel. Amplitude accuracy of the peak detect and hold circuit is 0.3% (absolute). TAC accuracy is within 0.3% of full scale. Power consumption is less than 2 mW/channel. Compared with conventional techniques such as track-and-hold and analog memory, this new ASIC will enable efficient pulse height measurement at 20 to 300 times higher rates.

O CONNOR,P.; DE GERONIMO,G.; KANDASAMY,A.

2002-11-10

31

Tunable laser diode system for noninvasive blood glucose measurements  

Science.gov (United States)

Tight control of blood glucose levels has been shown to dramatically reduce the long-term complications of diabetes. Current invasive technology for monitoring glucose levels is effective but underutilized by people with diabetes because of the pain of repeated finger-sticks and the cost of reagent strips. Optical sensing of glucose could potentially allow more frequent monitoring and tighter glucose control for people with diabetes. The key to a successful optical non-invasive 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 very small 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 ?m wavelength range. The system is based on a 2.3 micron 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 laser system and its potential for use in a non-invasive glucose sensor.

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

2005-03-01

32

2-NBDG as a fluorescent indicator for direct glucose uptake measurement.  

Science.gov (United States)

Evaluation of glucose uptake ability in cells plays a fundamental role in diabetes mellitus research. In this study, we describe a sensitive and non-radioactive assay for direct and rapid measuring glucose uptake in single, living cells. The assay is based on direct incubation of mammalian cells with a fluorescent d-glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG) followed by flow cytometric detection of fluorescence produced by the cells. A series of experiments were conducted to define optimal conditions for this assay. By this technique, it was found that insulin lost its physiological effects on cells in vitro meanwhile some other anti-diabetic drugs facilitated the cell glucose uptake rates with mechanisms which likely to be different from those of insulin or those that were generally accepted of each drug. Our findings show that this technology has potential for applications in both medicine and research. PMID:16182371

Zou, Chenhui; Wang, Yajie; Shen, Zhufang

2005-09-30

33

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The full impact of the liver, through both glucose production and uptake, on systemic glucose appearance cannot be readily studied in a classical glucose clamp because hepatic glucose metabolism is regulated not only by portal insulin and glucose levels but also portal glucose delivery (the portal signal). In the present study, we modified the classical glucose clamp by giving exogenous glucose through portal vein, the “portal glucose infusion (PoG)-glucose clamp”, to determine the net he...

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

2010-01-01

34

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Fluctuations in blood glucose level cause endothelial dysfunction and play a critical role in onset and/or progression of atherosclerosis. We hypothesized that fluctuation in blood glucose levels correlate with vascular endothelial dysfunction and that this relationship can be assessed using common bedside medical devices. Methods Fluctuations in blood glucose levels were measured over 24?hours by continuous glucose monitoring (CGM) on admi...

Torimoto Keiichi; Okada Yosuke; Mori Hiroko; Tanaka Yoshiya

2013-01-01

35

Proinsulin-transferrin fusion protein as a novel long-acting insulin analog for the inhibition of hepatic glucose production.  

Science.gov (United States)

Proinsulin-transferrin (ProINS-Tf) fusion protein was evaluated for its in vivo pharmacokinetics, efficacy, and mechanism. Our previous studies have shown that ProINS-Tf was converted to active insulin-transferrin (INS-Tf) via the transferrin (Tf)-receptor-mediated pathway in hepatoma cells. We hypothesized that this fusion protein can be administered as a prodrug and be converted to a biologically active protein with specificity for the liver versus other insulin (INS)-sensitive tissues (muscle and adipose). Administration as an inactive prodrug with liver-specific action compared with other INS-sensitive tissues conceivably reduces negative side effects seen with other INS analogs. In this report, the data show that ProINS-Tf exhibited a slow, but sustained, in vivo hypoglycemic efficacy and long plasma half-life. The fusion protein showed activity in the liver, as evidenced by decreased expression of two key hepatic glucose production (HGP) enzymes, PEPCK and glucose-6-phosphatase, and increased glycogen levels under feeding conditions. Furthermore, the INS receptor (IR) phosphorylation (activation) in liver and muscle tissues was compared with postinjection of INS or ProINS-Tf. While INS activated IR in both the liver and muscle, ProINS-Tf only showed activation in the liver. Thus, ProINS-Tf fusion protein can potentially be administered as a prodrug with sustained Tf-mediated activation and selectivity in inhibiting HGP. PMID:24353179

Wang, Yan; Shao, Juntang; Zaro, Jennica L; Shen, Wei-Chiang

2014-05-01

36

Comparative Study of the Effect of Baicalin and Its Natural Analogs on Neurons with Oxygen and Glucose Deprivation Involving Innate Immune Reaction of TLR2/TNF?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work is to study the baicalin and its three analogs, baicalin, wogonoside, and wogonin, on the protective effect of neuron from oxygen-glucose deprivation (OGD) and toll-like receptor 2 (TLR2) expression in OGD damage. The results showed that baicalin and its three analogs did protect neurons from OGD damage and downregulated protein level of TLR2. D-Glucopyranosiduronic acid on site 7 in the structure played a core of cytotoxicity of these flavonoid analogs. The methoxyl group on carbon...

Li, Hui-ying; Hu, Jun; Zhao, Shuang; Yuan, Zhi-yi; Wan, Hong-jiao; Lei, Fan; Ding, Yi; Xing, Dong-ming; Du, Li-jun

2012-01-01

37

Finger temperature controller for non-invasive blood glucose measurement  

Science.gov (United States)

Blood glucose level is an important parameter for doctors to diagnose and treat diabetes. The Near-Infra-Red (NIR) spectroscopy method is the most promising approach and this involves measurement on the body skin. However it is noted that the skin temperature does fluctuate with the environmental and physiological conditions and we found that temperature has important influences on the glucose measurement. In-vitro and in-vivo investigations on the temperature influence on blood glucose measurement have been carried out. The in-vitro results show that water temperature has significant influence on water absorption. Since 90% of blood components are water, skin temperature of measurement site has significant influence on blood glucose measurement. Also the skin temperature is related to the blood volume, blood volume inside capillary vessels changes with skin temperature. In this paper the relationship of skin temperature and signal from the skin and inside tissue was studied at different finger temperatures. Our OGTT (oral glucose tolerance test) trials results show the laser signals follow the skin temperature trend and the correlation of signal and skin temperature is much stronger than the correlation of signal and glucose concentration. A finger heater device is designed to heat and maintain the skin temperature of measurement site. The heater is controlled by an electronic circuit according to the skin temperature sensed by a thermocouple that is put close to the measurement site. In vivo trials were carried out and the results show that the skin temperature significantly influences the signal fluctuations caused by pulsate blood and the average signal value.

Zhang, Xiqin; Ting, Choon Meng; Yeo, Joon Hock

2010-11-01

38

Study on optical measurement conditions for noninvasive blood glucose sensing  

Science.gov (United States)

Utilizing Near-infrared Spectroscopy for non-invasive glucose concentration sensing has been a focusing topic in biomedical optics applications. In this paper study on measuring conditions of spectroscopy on human body is carried out and a series of experiments on glucose concentration sensing are conducted. First, Monte Carlo method is applied to simulate and calculate photons" penetration depth within skin tissues at 1600 nm. The simulation results indicate that applying our designed optical probe, the detected photons can penetrate epidermis of the palm and meet the glucose sensing requirements within the dermis. Second, we analyze the influence of the measured position variations and the contact pressure between the optical fiber probe and the measured position on the measured spectrum during spectroscopic measurement of a human body. And, a measurement conditions reproduction system is introduced to enhance the measurement repeatability. Furthermore, through a series of transmittance experiments on glucose aqueous solutions sensing from simple to complex we found that though some absorption variation information of glucose can be obtained from measurements using NIR spectroscopy, while under the same measuring conditions and with the same modeling method, choices toward measured components reduce when complication degree of components increases, and this causes a decreased prediction accuracy. Finally, OGTT experiments were performed, and a PLS (Partial Least Square) mathematical model for a single experiment was built. We can easily get a prediction expressed as RMSEP (Root Mean Square Error of Prediction) with a value of 0.5-0.8mmol/dl. But the model"s extended application and reliability need more investigation.

Xu, Kexin; Chen, Wenliang; Jiang, Jingying; Qiu, Qingjun

2004-05-01

39

A New Digit Positioning Method for Analog Measuring Instruments  

Directory of Open Access Journals (Sweden)

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

40

Comparison of extracellular and net glucose oxidation measured isotopically and by indirect calorimetry during high and low glucose turnover  

International Nuclear Information System (INIS)

To determine the extent to which glucose oxidation measured by indirect calorimetry reflects glucose oxidation measured isotopically, subjects were studied during a 6-h hyperinsulinemic euglycemic clamp (1 mU.kg-1.min-1) and during infusion of saline. [6-14C]glucose was infused on both occasions. Breath was collected for determination of the specific activity of carbon dioxide, oxygen consumption, and carbon dioxide production. Glucose turnover during hyperinsulinemia was approximately eightfold higher than during saline infusion. During the final 1.5 h of the hyperinsulinemic glucose clamp, oxidation measured isotopically remained slightly but consistently lower (P less than 0.05) than that measured by indirect calorimetry (13.8 +/- 1.1 vs 16.5 +/- 1.7 mumol.kg-1.min-1, respectively). In contrast, during the saline infusion, glucose oxidation measured isotopically did not differ from that measured by indirect calorimetry (8.3 +/- 0.6 vs 7.2 +/- 2.8 mumol.kg-1.min-1, respectively). We conclude that although net glucose oxidation measured isotopically was slightly lower than that measured by indirect calorimetry, both techniques provide similar estimates of glucose oxidation over a wide range of glucose disposal

1991-01-01

 
 
 
 
41

Multidoored analogical scintigraphic device. Measurement of the ejection fraction  

International Nuclear Information System (INIS)

The determination of left ventricular ejection fraction and radionuclide ventriculography can easily be obtained in analog mode with a modified multiimaging device triggered by the patient's electrocardiogram

1977-01-01

42

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

43

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 "1"4C ?-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 "1"4C activities. When compared to either control group, the mean "1"4C 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 "1"4C were reduced (p < 0.01 or lower) in the EF fetal tissues and placenta. Maternal ethanol ingestion reduced the "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

1986-05-01

44

No evidence for isotope discrimination of tritiated glucose tracers in measurements of glucose turnover rates in man.  

Science.gov (United States)

Under non-steady-state conditions, glucose turnover rates determined with tritiated glucose tracers are often underestimated. To examine whether isotope discrimination or a tracer contaminant can contribute to this, we compared the turnover rates of unlabelled and tritiated glucose under isotopic steady-state conditions. The turnover rates were measured in 20 healthy subjects at two insulin concentrations (79 +/- 3 mU.l-1 and 704 +/- 62 mU.l-1). Euglycaemia was maintained by infusing unlabelled glucose mixed with (3(3)H)- or (6(3)H)-glucose. In both studies, the isotopically determined glucose disposal rate was virtually identical to the exogenous glucose infusion rate (low insulin 7.66 +/- 0.48 vs 7.58 +/- 0.44 mg.kg-1.min-1, high insulin 13.36 +/- 0.74 vs 13.55 +/- 0.98 mg.kg-1.min-1). The individual values were correlated in both the low (r = 0.85, p less than 0.001) and high dose insulin (r = 0.81, p less than 0.001) studies. Tritiated glucose specific activities were also compared in arterialized and deep venous blood across forearm tissues during the high-dose insulin infusion. Glucose specific activities were similar in arterialized and deep venous blood when analysed with HPLC and conventional methods. In summary: (1) Under isotopic steady-state conditions the turnover rates of unlabelled and labelled glucoses are similar. (2) Unlabelled and labelled glucose are handled identically across forearm tissues. (3) We found no tracer impurity in our tritiated glucose preparations. We conclude that (3(3)H)- and (6(3)H)-glucose tracers can be used to reliably measure glucose turnover rates in man. PMID:2184069

Koivisto, V A; Yki-Järvinen, H; Puhakainen, I; Virkamäki, A; Kolaczynski, J; DeFronzo, R

1990-03-01

45

Near-infrared spectral methods for noninvasively measuring blood glucose  

Science.gov (United States)

Determination of blood glucose concentrations in diabetic patients is a frequently occurring procedure and an important tool for diabetes management. Use of noninvasive detection techniques can relieve patients from the pain of frequent finger pokes and avoid the infection of disease via blood. This thesis discusses current research and analyzes the advantages and shortages of different measurement methods, including: optical methods (Transmission, Polarimetry and scattering), then, we give emphasis to analyze the technology of near-infrared (NIR) spectra. NIR spectral range 700 nm ~2300 nm was used because of its good transparency for biological tissue and presence of glucose absorption band. In this work, we present an outline of noninvasive blood glucose measurement. A near-infrared light beam is passed through the finger, and the spectral components of the emergent beam are measured using spectroscopic techniques. The device includes light sources having the wavelengths of 600 nm - 1800 nm to illuminate the tissue. Receptors associated with the light sources for receiving light and generating a transmission signal representing the light transmitted are also provided. Once a transmission signal is received by receptors, and the high and low values from each of the signals are stored in the device. The averaged values are then analyzed to determine the glucose concentration, which is displayed on the device.

Fei, Sun; Kong, Deyi; Mei, Tao; Tao, Yongchun

2004-05-01

46

Comparative study of the effect of baicalin and its natural analogs on neurons with oxygen and glucose deprivation involving innate immune reaction of TLR2/TNF?.  

Science.gov (United States)

This work is to study the baicalin and its three analogs, baicalin, wogonoside, and wogonin, on the protective effect of neuron from oxygen-glucose deprivation (OGD) and toll-like receptor 2 (TLR2) expression in OGD damage. The results showed that baicalin and its three analogs did protect neurons from OGD damage and downregulated protein level of TLR2. D-Glucopyranosiduronic acid on site 7 in the structure played a core of cytotoxicity of these flavonoid analogs. The methoxyl group on carbon 8 of the structure had the relation with TLR2 protein expression, as well as the anti-inflammation. In addition, we detected caspase3 and antioxidation capability, to investigate the effect of four analogs on cell apoptosis and total antioxidation competence in OGD model. PMID:22536016

Li, Hui-Ying; Hu, Jun; Zhao, Shuang; Yuan, Zhi-Yi; Wan, Hong-Jiao; Lei, Fan; Ding, Yi; Xing, Dong-Ming; Du, Li-Jun

2012-01-01

47

Comparative Study of the Effect of Baicalin and Its Natural Analogs on Neurons with Oxygen and Glucose Deprivation Involving Innate Immune Reaction of TLR2/TNF?  

Science.gov (United States)

This work is to study the baicalin and its three analogs, baicalin, wogonoside, and wogonin, on the protective effect of neuron from oxygen-glucose deprivation (OGD) and toll-like receptor 2 (TLR2) expression in OGD damage. The results showed that baicalin and its three analogs did protect neurons from OGD damage and downregulated protein level of TLR2. D-Glucopyranosiduronic acid on site 7 in the structure played a core of cytotoxicity of these flavonoid analogs. The methoxyl group on carbon 8 of the structure had the relation with TLR2 protein expression, as well as the anti-inflammation. In addition, we detected caspase3 and antioxidation capability, to investigate the effect of four analogs on cell apoptosis and total antioxidation competence in OGD model.

Li, Hui-Ying; Hu, Jun; Zhao, Shuang; Yuan, Zhi-Yi; Wan, Hong-Jiao; Lei, Fan; Ding, Yi; Xing, Dong-Ming; Du, Li-Jun

2012-01-01

48

Noninvasive blood glucose measurement using multiple laser diodes  

Science.gov (United States)

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

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

2007-03-01

49

Noninvasive polarimetric glucose measurement system for eye phantoms and in-vivo measurement requirements  

Science.gov (United States)

Non-invasive monitoring of the glucose level is a key technology for improved diagnosis and therapy for Diabetes patients. Optical measurement techniques like polarimetry measuring at the human eye offer promising properties for non-invasive and painless application. This article presents a polarimetric measurement system utilizing the polarizing properties of the Aqueous Humour (AH) for quantative glucose measurements. In particular the special requirements of in-vivo measurements for such a system are discussed.

Rawer, Rainer C.; Vollmer, Patrick; Malz, André; Stork, Wilhem; Müller-Glaser, Klaus D.

2003-10-01

50

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

51

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

International Nuclear Information System (INIS)

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

1991-01-01

52

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1995-01-01

53

Polarimetric methods for measurement of intra ocular glucose concentration.  

Science.gov (United States)

Due to the increasing lifespan in the industrialized world the number of senior Diabetes patients is growing rapidly. Using non-invasive techniques, measurements of the blood sugar level could be done more frequently and hence diagnosis as well as therapy of type II Diabetes Mellitus can be improved especially for this group of senior patients. Especially polarimetric techniques measuring at the human eye offer promising properties for non-invasive and painless measurement. This article discusses different approaches for utilizing the polarizing properties of the Aqueous Humour (AH) for quantitative glucose measurements. PMID:12451812

Rawer, R; Stork, W; Müller-Glaser, K D

2002-01-01

54

Transient measurement of glucose using on-off controllable enzyme electrode with polypyrrole membrane  

Energy Technology Data Exchange (ETDEWEB)

A glucose sensor, using glucose oxidase immobilized in an electrically conductive polymer membrane, is developed for transient-mode measurement by on-off reaction control in the present work. An implantable glucose sensor loses its stability under the skin by fouling resulting from fibroblast adhesion on the glucose oxidase-immobilized membrane. Change in glucose distribution inside the membrane and in the vicinity of the surface of the membrane resulting from the fouling makes the measurement of the glucose concentration unstable. A technique of measuring transient current of the glucose sensor after activation of glucose oxidase may hardly be affected by the fouling as oxidation of coenzyme of glucose oxidase is rapid and the transient current is sensitive to glucose concentration. A glucose sensor with glucose oxidase immobilized in an electrically conductive polypyrrole membrane was fabricated. The activity of the glucose oxidase is switched on and off by a stepwise change of potential of the polypyrrole membrane from 0.15 V to 0.45 V versus a saturated calomel electrode. The two conditions described above can be confirmed by measuring transient current. Current increased momentarily after activation of glucose oxidase and decreased moderately after that. The oxidation and reduction of glucose oxidase is sufficiently rapid, and current intensity depends on glucose concentration in the test solution. 12 refs., 8 figs.

Miyasaka, T.; Yoshimi, Y.; Sakai, K. [Waseda University, Tokyo (Japan)

1998-02-01

55

Flap Salvage Following Postoperative Venous Thrombosis Diagnosed by Blood Glucose Measurement in the Flaps  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective: This is the first paper to report the measurement of blood glucose in flaps to detect early flap congestion and flap salvage following immediate flap exploration. Methods: We performed blood glucose measurement in a superficial circumflex iliac artery perforator flap and an anterolateral thigh flap postoperatively using Medisafe-Mini (Terumo, Japan), a regular capillary blood glucose–monitoring device. Results: The blood glucose measurements were low when in early venous thrombos...

2011-01-01

56

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-05-01

57

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

58

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

Directory of Open Access Journals (Sweden)

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

Torimoto Keiichi

2013-01-01

59

Approaches for Improving Glucose Monitor Measurements for Self-Monitoring of Blood Glucose: From Measurement Harmonization to External Quality Assessment Programs  

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Self-monitoring of blood glucose (SMBG) is an important component in diabetes management, helping patients to achieve and maintain normal blood glucose levels. The benefit of SMBG depends on the quality of the measurement performed. Therefore, it is important to know the factors affecting the measurements and to assure that the quality of SMBG measurements is at the highest achievable level possible. To accomplish this, all aspects of the measurement procedure need to be taken into considerat...

2007-01-01

60

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; ["1"4C]-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 ["1"4C]-6-glucose (2.3 +/- 0.1 mg X kg-1 X min-1) was greater than that determined with [3"3H]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 ["1"4C]-6-glucose continued to be less than those determined with ["3H]-2-glucose and greater than those seen with ["3H]-3-glucose

1986-01-01

 
 
 
 
61

Localized 1H NMR measurement of glucose consumption in the human brain during visual stimulation.  

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Spatially localized 1H NMR spectroscopy has been applied to measure changes in brain glucose concentration during 8-Hz photic stimulation. NMR spectroscopic measurements were made in a 12-cm3 volume centered on the calcarine fissure and encompassing the primary visual cortex. The average maximum change in glucose levels was 0.34 mumol.g-1 (n = 5) at 15 min; glucose level had turned toward resting level at 25 min. The glucose change was used to calculate the increase of glucose cerebral metabo...

1993-01-01

62

Insulin analogs  

Directory of Open Access Journals (Sweden)

Full Text Available The fear of hypoglycemia that people with diabetes experience is a factor in non-adherence to insulin therapy, which can adversely affect glycemic control and increase the risk of diabetes-associated complications. Insulin analogs are modified forms of human insulin designed to mimic endogenous insulin secretion, and may therefore help to reduce the risk and severity of hypoglycemia. While much evidence exists to demonstrate the efficacy of insulin analogs in blood glucose control, the effects on the incidence of severe hypoglycemia are less clear. This treatment review presents recent studies investigating the effects of insulin analogs on the frequency of hypoglycemia.

Emily Chu

2012-06-01

63

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

64

Measurement of sand-powders and analogical analysis on sandstorm at W band  

Science.gov (United States)

Dielectric constant of sand-powders sampled from desert area have been measured at W band by means of waveguide method. The algorithm about equivalent dielectric constant of analogical sandstorm have been discussed. It is very useful to test the sand-powders of the desert sample at laboratory, to make analogical analysis of sandstorm and to research the effects of sandstorm in desert area upon electric wave propagations.

Dong, Shuyi; Lan, Xing; Sun, Xiaowei; Yan, Yi

1994-08-01

65

Evaluation of a Minimally Invasive System for Measuring Glucose Area under the Curve during Oral Glucose Tolerance Tests: Usefulness of Sweat Monitoring for Precise Measurement  

Science.gov (United States)

Aims: We developed a system for measuring glucose area under the curve (AUC) using minimally invasive interstitial fluid extraction technology (MIET). Sweat contamination during interstitial fluid glucose (IG) extraction affects the accuracy of glucose AUC measurement, because this technology uses extracted sodium ion levels as an internal standard. Therefore, we developed a sweat monitoring patch to reduce this effect and investigated its efficacy in volunteers undergoing oral glucose tolerance tests (OGTTs). Materials and Methods: Fifty diabetes mellitus inpatients and 10 healthy subjects undergoing the 75 g OGTT were included. Two sites on the forearm were pretreated with microneedle arrays, then hydrogels for interstitial fluid extraction were placed on the treated sites. Simultaneously, hydrogels for sweat monitoring were placed on untreated sites near the treated sites. Plasma glucose (PG) levels were measured every 30 min for 2 h to calculate reference AUC values. Using MIET, IG AUC was calculated from extracted glucose and sodium ion levels after attachment of the hydrogel for 2 h. Results: Good correlation between IG AUC measurements using MIET and reference AUCs measured using PG levels was confirmed over a wide AUC range (202–610 mg/h/dl) after correction for the sweat-induced error detected by the hydrogel patches on the nonpretreated skin. Strong correlation between IG AUC and peak glucose levels indicates that glucose spikes can be easily detected by this system. Conclusion: We confirmed the effectiveness of a sweat monitoring patch for precise AUC measurement using MIET. This novel, easy-to-use system has potential for glucose excursion evaluation in daily clinical practice.

Sakaguchi, Kazuhiko; Hirota, Yushi; Hashimoto, Naoko; Ogawa, Wataru; Hamaguchi, Tomoya; Toshihiro, Matsuo; Miyagawa, Jun-ichiro; Namba, Mitsuyoshi; Sato, Toshiyuki; Okada, Seiki; Tomita, Koji; Matsuhisa, Munehide; Kaneto, Hideaki; Kosugi, Keisuke; Maegawa, Hiroshi; Nakajima, Hiromu; Kashiwagi, Atsunori

2013-01-01

66

Non-invasive Glucose Measurements Using Wavelength Modulated Differential Photothermal Radiometry (WM-DPTR)  

Science.gov (United States)

Wavelength-modulated differential laser photothermal radiometry (WM-DPTR) is introduced for potential development of clinically viable non-invasive glucose biosensors. WM-DPTR features unprecedented glucose-specificity and sensitivity by combining laser excitation by two out-of-phase modulated beams at wavelengths near the peak and the baseline of a prominent and isolated mid-IR glucose absorption band. Measurements on water-glucose phantoms (0 to 300 mg/dl glucose concentration) demonstrate high sensitivity to meet wide clinical detection requirements ranging from hypoglycemia to hyperglycemia. The measurement results have been validated by simulations based on fully developed WM-DPTR theory. For sensitive and accurate glucose measurements, the key is the selection and tight control of the intensity ratio and the phase shift of the two laser beams.

Guo, X.; Mandelis, A.; Zinman, B.

2012-11-01

67

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

1985-05-01

68

Measurement of dynamic gas disengagement profile by using an analog output level gauge  

Science.gov (United States)

The dynamic gas disengagement profile was measured in a 0.14 m diameter and 3.66 m high plexiglas column by using an analog output gauge, which was connected to a data acquisition system. This analog output gauge is a high accuracy continuous measurement level gauge. It is made up of a wave guide, a float, a motion or stress sensing device and a probe housing. The fluid level at any gas velocity is obtained by using the data acquisition system. The dynamic gas disengagement profile produced one slope in the bubble flow and two slopes in the churn turbulent flow representing unimodal and bimodal distributions of bubbles.

Mikkilineni, S.; Koelle, M.; Xu, H.

69

Measurement of glucose uptake and intracellular calcium concentration in single, living pancreatic beta-cells.  

Science.gov (United States)

There has been no method previously to measure both glucose transport and its effect on the various intracellular functions in single, living mammalian cells. A fluorescent derivative of d-glucose, 2-[N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl)amino]-2-deoxy-d-glucose (2-NBDG), that we have developed has made such measurements possible. COS-1 cells that overexpress the human glucose transporter GLUT2 show significantly greater 2-NBDG uptake than mock transfected cells. Using GLUT2-abundant mouse insulin-secreting clonal MIN6 cells, we found that 2-NBDG was incorporated into the cells in a time- and concentration-dependent manner. The 2-NBDG uptake was inhibited by high concentrations of d-glucose in a dose-dependent manner and also was almost completely inhibited by 10 micrometer cytochalasin B. We then measured both glucose uptake and the intracellular calcium concentration ([Ca(2+)](i)) in single, living pancreatic islet cells. 2-NBDG and fura-2 were used as the tracer of glucose and indicator of intracellular calcium, respectively. All of the cells that showed an increase in [Ca(2+)](i) in response to a high concentration of glucose (16.8 mm) rapidly incorporated significant 2-NBDG. Immunocytochemical examination confirmed these cells to be insulin-positive beta-cells. All of the cells that showed no significant, rapid 2-NBDG uptake lacked such glucose responsiveness of [Ca(2+)](i), indicating that these cells were non-beta-cells such as glucagon-positive alpha-cells. These results show the uptake of glucose causing a concomitant increase of [Ca(2+)](i) in beta-cells. Because 2-NBDG is incorporated into mammalian cells through glucose transporters, it should be useful for the measurement of glucose uptake together with concomitant intracellular activities in many types of single, living mammalian cells. PMID:10748091

Yamada, K; Nakata, M; Horimoto, N; Saito, M; Matsuoka, H; Inagaki, N

2000-07-21

70

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

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

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

2011-01-01

71

Noninvasive polarimetric measurement of glucose in cell culture media  

Science.gov (United States)

In order to enhance cell culture growth in bioreactors, biosensors such as those used for glucose detection must be developed that are capable of monitoring cell culture processes continuously and preferably noninvasively. The development of a unique noninvasive, optically based polarimetric glucose sensor is reported. The data were collected using a highly sensitive, lab-built polarimeter with digital feedback and a red laser diode source. A range of glucose concentrations was evaluated using both glucose- doped double-distilled water and a bovine serum-based medium. The serum-based medium is the nutritional environment in which the cell cultures are grown. Both media were examined across two glucose concentration ranges--a lower range of 100 mg/dl in 10-mg/dl increments and a higher range up to 600 mg/dl in 50-mg/dl increments. The linear regression in all experiments yielded standard errors of prediction of less than 8.5 mg/dl across both ranges.

Cote, Gerard L.; Cameron, Brent D.

1997-07-01

72

Underestimation of glucose turnover measured with [6-3H]- and [6,6-2H]- but not [6-14C]glucose during hyperinsulinemia in humans  

International Nuclear Information System (INIS)

Recent studies indicate that hydrogen-labeled glucose tracers underestimate glucose turnover in humans under conditions of high flux. The cause of this underestimation is unknown. To determine whether the error is time-, pool-, model-, or insulin-dependent, glucose turnover was measured simultaneously with [6-3H]-, [6,6-2H2]-, and [6-14C]glucose during a 7-h infusion of either insulin (1 mU.kg-1.min-1) or saline. During the insulin infusion, steady-state glucose turnover measured with both [6-3H]glucose (8.0 +/- 0.5 mg.kg-1.min-1) and [6,6-2H2]glucose (7.6 +/- 0.5 mg.kg-1.min-1) was lower (P less than .01) than either the glucose infusion rate required to maintain euglycemia (9.8 +/- 0.7 mg.kg-1.min-1) or glucose turnover determined with [6-14C]glucose and corrected for Cori cycle activity (9.8 +/- 0.7 mg.kg-1.min-1). Consequently negative glucose production rates (P less than .01) were obtained with either [6-3H]- or [6,6-2H2]- but not [6-14C]glucose. The difference between turnover estimated with [6-3H]glucose and actual glucose disposal (or 14C glucose flux) did not decrease with time and was not dependent on duration of isotope infusion. During saline infusion, estimates of glucose turnover were similar regardless of the glucose tracer used. High-performance liquid chromatography of the radioactive glucose tracer and plasma revealed the presence of a tritiated nonglucose contaminant. Although the contaminant represented only 1.5% of the radioactivity in the [6-3H]glucose infusate, its clearance was 10-fold less (P less than .001) than that of [6-3H]glucose. This resulted in accumulation in plasma, with the contaminant accounting for 16.6 +/- 2.09 and 10.8 +/- 0.9% of what customarily is assumed to be plasma glucose radioactivity during the insulin or saline infusion, respectively (P less than .01)

1989-01-01

73

Shape information from glucose curves: Functional data analysis compared with traditional summary measures  

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Abstract Background Plasma glucose levels are important measures in medical care and research, and are often obtained from oral glucose tolerance tests (OGTT) with repeated measurements over 2–3?hours. It is common practice to use simple summary measures of OGTT curves. However, different OGTT curves can yield similar summary measures, and information of physiological or clinical interest may be lost. Our mean aim was to extract information inherent in the shape of OGTT g...

Frøslie Kathrine Frey; Røislien Jo; Qvigstad Elisabeth; Godang Kristin; Bollerslev Jens; Voldner Nanna; Henriksen Tore; Veierød Marit B

2013-01-01

74

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

International Nuclear Information System (INIS)

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

1988-09-12

75

Immunocytochemistry of GLUT2, uptake of fluorescent desnitroso-streptozotocin analogs and phosphorylation of D-glucose in INS-1E cells.  

Science.gov (United States)

The non-invasive imaging of GLUT2-expressing cells remains a challenge. As streptozotocin, and similarly alloxan, may be transported into cells by GLUT2, the major aim of the present study was to assess the possible use of fluorescent desnitroso-streptozotocin analogs for in vitro labeling of GLUT2-expressing cells. INS-1E cells, human embryonic kidney (HEK) cells, rat isolated pancreatic islets, rat hepatic cells, rat exocrine pancreatic cells and tumoral insulin-producing BRIN-BD11 cells were incubated in the presence of two distinct fluorescent desnitroso-streptozotocin analogs, probes A and B. The immunocytochemistry of GLUT2 in INS-1E cells and the phosphorylation of D-glucose by INS-1E cell homogenates were also examined. The uptake of probes A and B (12.0 µM) by INS-1E cells yielded apparent intracellular concentrations approximately one order of magnitude higher than the extracellular concentration. The two probes differed from one another by the absolute values for their respective uptake and time course, but not so by the pattern of their concentration dependency. Comparable results were recorded in HEK cells, rat isolated pancreatic islets and hepatocytes. Vastly different findings were recorded, however, in rat exocrine pancreatic cells, which do not express GLUT2. Moreover, an unusual concentration dependency for the uptake of each probe was observed in tumoral BRIN-BD11 cells. It is proposed that suitable fluorescent desnitroso-streptozotocin analogs may be used to label GLUT2-expressing cells. PMID:23807415

Virreira, Myrna; Popescu, Iuliana; Gillet, Celine; Zhang, Ying; Leshch, Yevgeniy; Thimm, Julian; Thiem, Joachim; Malaisse, Willy J; Sener, Abdullah

2013-08-01

76

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

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

Camacho SL

2012-05-01

77

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

1975-10-20

78

Measurements of serum glucose using the luciferin/Luciferase system and a liquid scintillation spectrometer  

International Nuclear Information System (INIS)

A single-step assay for serum glucose measurements is described. The assay is based on the phosphorylation of D-glucose by glucokinase and the measurement of ATP consumption by firefly luciferase. The luminescence is recorded in an ordinary liquid scintillation spectrometer. The use of stable reagents and a stable final signal (light emission) makes it possible to analyze a large number of samples in each assay run. The assay is of particular value when repeated serum glucose determinations are performed on samples from small laboratory animals

1986-05-15

79

Measurements of serum glucose using the luciferin/Luciferase system and a liquid scintillation spectrometer  

Energy Technology Data Exchange (ETDEWEB)

A single-step assay for serum glucose measurements is described. The assay is based on the phosphorylation of D-glucose by glucokinase and the measurement of ATP consumption by firefly luciferase. The luminescence is recorded in an ordinary liquid scintillation spectrometer. The use of stable reagents and a stable final signal (light emission) makes it possible to analyze a large number of samples in each assay run. The assay is of particular value when repeated serum glucose determinations are performed on samples from small laboratory animals.

Idahl, L.A.; Sandstroem, P.E.; Sehlin, J.

1986-05-15

80

Oxygen effects on glucose measurements with a reference analyzer and three handheld meters.  

Science.gov (United States)

Oxygen may affect glucose meter and reference analyzer measurements. We evaluated the effects of changes in blood oxygen tension (Po2) on Accu-Chek Comfort Curve (Roche Diagnostics, Indianapolis, IN), Precision G, (Abbott Laboratories, Bedford, MA) and One Touch II (Lifescan, Milpitas, CA) glucose meter measurements, and on Yellow Springs Instruments (YSI) (Yellow Springs, OH) reference analyzer measurements. Venous blood drawn from healthy volunteers was adjusted to three glucose levels of 80, 200, and 400 mg/dL, each tonometered with six different Po2 levels (40, 80, 160, 240, 320, and 400 torr). To quantitate oxygen effects on reference analyzer measurements, glucose differences between test sample (Po2 changed) and control (Po2 80 torr) were calculated (YSItest-YSIcontrol). The threshold for determination of oxygen effects was +/-2 SD, where 2 SD was fro PMID:11467337

Tang, Z; Louie, R F; Payes, M; Chang, K C; Kost, G J

2000-01-01

 
 
 
 
81

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)

1992-12-01

82

Blood Glucose Monitoring Devices  

Science.gov (United States)

... with glucose. Some meters measure the amount of electricity that passes through the test strip. Others measure ... with Glucose Meters and Continuous Glucose Monitoring Systems Users of Blood Glucose Meters Must Use Only the ...

83

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

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

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

2011-01-01

84

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.

85

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

Energy Technology Data Exchange (ETDEWEB)

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.

Liu Rong [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072 (China); Chen Wenliang [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072 (China); Gu Xiaoyu [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072 (China); Wang, Ruikang K [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072 (China); Institute of Bioscience and Technology, Cranfield University at Silsoe, Bedfordshire MK45 4DT (United Kingdom); Xu Kexin [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072 (China)

2005-08-07

86

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

2005-08-07

87

Performance of two portable meters and a benchtop analyzer for blood glucose concentration measurement in rabbits.  

Science.gov (United States)

Objective-To evaluate performance of a human portable blood glucose meter (PBGM), a veterinary PBGM, and a veterinary benchtop analyzer for measuring blood glucose concentration in rabbits and to evaluate the effect of sample characteristics on their performance. Design-Observational prospective cross-sectional study. Sample-Blood samples from 89 pet rabbits. Procedures-Blood glucose concentration was measured with a human PBGM (n = 89 rabbits), a veterinary PBGM (89), and a benchtop analyzer (32) and compared with results obtained with plasma in a laboratory analyzer (hexokinase method). Results-The human PBGM underestimated blood glucose concentration, had decreased accuracy at high Hcts, and had the lowest total error observed (11.4%). The veterinary PBGM overestimated blood glucose concentration, had decreased accuracy at low Hcts and at high blood glucose concentrations, and had the highest total error (15.5% and 29.8% for canine and feline settings, respectively). The benchtop analyzer had good accuracy and was not influenced by Hct or glucose concentrations. Clinical errors would have occurred in 0% of cases with the human PBGM and with the benchtop analyzer and in 9% (canine setting) to 6.7% (feline setting) of cases with the veterinary PBGM. Conclusions and Clinical Relevance-Results suggested that use of the human PBGM evaluated in this study would be acceptable for point-of-care testing of blood glucose concentration in rabbits when benchtop analyzers are not available. The use of the veterinary PBGM evaluated in this study may alter both treatment and diagnostic decisions because of the overestimation of glucose concentrations in some rabbits. PMID:24941392

Selleri, Paolo; Di Girolamo, Nicola; Novari, Gianluca

2014-07-01

88

Wavelength-modulated differential laser photothermal radiometry for blood glucose measurements  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-03-01

89

Real-time measurement of glucose concentration and average refractive index using a laser interferometer  

Science.gov (United States)

This study presents a non-destructive, highly precise optical metrology system for measuring the average refractive index of a liquid solution such that its glucose concentration can be derived. The metrology system is employed to measure the average refractive indices of samples with known glucose concentrations ranging from 0 to 200 g/l. By applying a regressional analysis technique to the experimental results, an analytical expression is derived to describe the relationship between the refractive index and the glucose concentration. An excellent agreement is observed between the experimentally determined values of the glucose concentration and the analytically derived results. For an assumed laser interferometer resolution of 1 nm, the measurement resolution of the proposed metrology system is found to be at least F=0.05 g/l, which is significantly better than that of F=2 g/l obtained using the polarimetric glucose sensor presented by Lo and Yu [A polarimetric glucose sensor using a liquid-crystal polarization modulator driven by a sinusoidal signal. Opt Commun, 2006; 259: 40-8].

Yeh, Yen-Liang

2008-09-01

90

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

Science.gov (United States)

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

Coté, G L; Fox, M D; Northrop, R B

1992-07-01

91

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

92

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

93

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

2003-08-07

94

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-12-01

95

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.

96

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.)

1994-03-01

97

Multiwell plates loaded with fluorescent hydrogel sensors for measuring pH and glucose concentration  

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Fluorescent hydrogels were polymerized directly in multi-well plates at ambient temperature and in the presence of air, producing sensors for measuring pH and glucose concentration. The plates were rapidly analyzed using a fluorescence plate reader. Multiwell pH sensors with good reproducibility among different wells and a dynamic range from pH 6 to 9 were prepared by incorporating a polymerizable pH sensitive fluorophore in the hydrogel. Non-enzymatic glucose sensors comprising a boronic aci...

Vilozny, Boaz; Schiller, Alexander; Wessling, Ritchie A.; Singaram, Bakthan

2011-01-01

98

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

99

The Balloon Analog Insurance Task (BAIT): a behavioral measure of protective risk management.  

Science.gov (United States)

Prior methods used to assess individual differences related to risk have not focused on an important component of risk management: how willing individuals are to pay for or take actions to insure what they already have. It is not clear whether this type of protective risk management taps into the same individual differences as does risk taking propensity measured by existing risk taking tasks. We developed a novel task to assess protective risk management, the Balloon Analog Insurance Task (BAIT), which is modeled after the Balloon Analog Risk Task (BART). In the BAIT, individuals are forced to decide how much money they are willing to pay in order to insure a specific fraction of their prior winnings given changing but imprecise levels of risk of monetary loss. Participants completed the BART and BAIT for real monetary rewards, and completed six self report questionnaires. The amount of insurance purchased on the BAIT was positively correlated with scores on the Intolerance of Uncertainty Scale and on the Checking scale of the revised Obsessive Compulsive Inventory. Conversely, the amount of insurance purchased was negatively correlated with scores on the Domain Specific Risk Taking Questionnaire, and on the Psychopathic Personality Inventory (PPI). Furthermore, relationships between insurance purchased and these scales remained significant after controlling for the BART in linear regression analyses, and the BART was only a significant predictor for measures on one scale--the PPI. Our results reveal that behavior on the BAIT taps into a number of individual differences that are not related to behavior on another measure of risk taking. We propose that the BAIT may provide a useful complement to the BART in the assessment of risk management style. PMID:21738666

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

2011-01-01

100

Dynamics of glucose uptake by single Escherichia coli cells.  

Science.gov (United States)

The fluorescent glucose analog, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), was used to measure rates of glucose uptake by single Escherichia coli cells. When cell populations were exposed to the glucose analog, 2-NBDG was actively transported and accumulated in single cells to a steady-state level that depended upon its extracellular concentration, the glucose transport capacity of the cells, and the intracellular degradation rate. The dependence upon substrate concentration could be described according to Michaelis-Menten kinetics with apparent saturation constant KM = 1.75 microM, and maximum 2-NBDG uptake rate= 197 molecules/cell-second. Specificity of glucose transporters to the analog was confirmed by inhibition of uptake of 2-NBDG by D-glucose, 3-o-methyl glucose, and D-glucosamine, and lack of inhibition by L-glucose. Inhibition of 2-NBDG uptake by D-glucose was competitive in nature. The assay for 2-NBDG uptake is extremely sensitive such that the presence of even trace amounts of D-glucose in the culture medium (approximately 0.2 microM) is detectable. The rates of single-cell analog uptake were found to increase proportionally with cell size as measured by microscopy or single-cell light scattering intensity. The assay was used to identify and isolate mutant cells with altered glucose uptake characteristics. A mathematical model was developed to provide a theoretical basis for estimating single-cell glucose uptake rates from single-cell 2-NBDG uptake rates. The assay provides a novel means of estimating the instantaneous rates of nutrient depletion in the growth environment during a batch cultivation. PMID:10937825

Natarajan, A; Srienc, F

1999-10-01

 
 
 
 
101

Use of 11C-deoxyglucose for the measurement of local cerebral glucose metabolism in humans  

International Nuclear Information System (INIS)

The 18F-fluorodeoxyglucose technique for the measurement of local cerebral glucose metabolism (LCMRgl) has been widely applied in humans. Repeat studies over a relatively brief period of time have not been possible because of the 110-min half-life of fluorine-18. With the synthesis of 11C-deoxyglucose it has now become possible to utilize this short lived (20 min) tracer for the measurement of LCMRgl. The ability to perform repeat studies within a few hours of each other allows one to make control and experimental measurements in the same subject. This reduces inter-subject variation and allows smaller changes in regional glucose metabolism to be detected reliably. LCMRgl measurements in humans utilizing 11C-deoxyglucose in serial studies in the same subject are presented. (Auth.)

1983-01-01

102

Application of muscle biopotential measurement for sustained, noninvasive blood glucose survey.  

Science.gov (United States)

Biopotential, the electric potential generated by living tissues, is affected by changes in extracellular electrolyte and glucose concentrations. We aimed to apply correlation between blood glucose concentrations (BGC) and biopotential of peripheral muscles for noninvasive blood glucose measurement. The study included 58 Wistar rats. In part of them, diabetes was induced by streptozotocin injection. Group 1, comprising 19 normal and 5 diabetic rats, received glucose-challenging protocol (intraperitoneal injection of 1 g/ml glucose). Group 2, 24 normal and 6 diabetic rats, received insulin-challenging protocol (three 30 IU insulin injections with 15-min intervals). Four control rats, group 3, were injected with 2-ml saline. BGC were measured by a standard ACCU-CHEK-Sensor Meter and compared with those estimated by biopotential sensor, further designated as GlucoSat, placed around proximal parts of the tails of the anaesthetized animals. GlucoSat results were calculated using the following biopotential equation: BGC(t) = k1 F1(t) + k2 F2(t) k3 F3(t) + k4, based on an experimental model involving estimation of pH, muscle metabolism, and tissue conductance, where t is time, k1-k4 are coefficients, and F1-F4 are functions. Mean biopotential system measured BGC was 181.7 +/- 4.3 mg/dl, not differing statistically from 187.9 +/- 4.3 mg/dl estimated by ACCU-CHEK. Pearson's correlation coefficient (r(2)) was 0.961 (P < 0.00001), indicating strong, direct correlation between the results. Within the nondiabetic group, r(2) was 0.944 (P < 0.00001), while, within the diabetic group, r(2) was 0.974 (P < 0.00001). No significant, adverse skin reactions were concomitantly observed in any experimental group. Biopotential measurements may be used for continuous, noninvasive estimation of changes in BGC. Further studies are needed to evaluate the applicability of this method to humans. PMID:19265065

Vol, Alexander; Gribova, Orna; Berman, Sylvia; Siman-Tov, Yariv; Efrati, Shai

2009-07-01

103

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

1977-01-01

104

Simultaneous measurement of glucose and glutamine in insect cell culture media by near infrared spectroscopy.  

Science.gov (United States)

The purpose of this study was to develop non-invasive techniques to monitor the composition of cell culture media in insect cell bioreactors. Such a monitor could be used in conjunction with a fed-batch feeding scheme to ensure that cells are maintained in an optimal environment for growth and protein production. Glucose and glutamine concentrations in an insect cell culture bioreactor were determined off-line with near-infrared (NIR) absorption spectroscopy. Spectra were collected from 5000 to 4000 cm(-1) with a 1.5-mm optical path length. Partial least squares (PLS) regression was applied to correlate the collected spectra with the concentration of the desired analytes. Under the culture conditions evaluated here, glucose and glutamine concentrations ranged from 38 to 55 mM and from 3 to 13 mM, respectively. Accurate measurements of glucose and glutamine in insect cell culture samples were possible over these entire ranges. The standard error of prediction (SEP) and mean percent error (MPE) for glutamine were 0.52 mM and 5.3%, respectively. Glucose could be measured with an SEP of 1.30 mM and an MPE of 2.3%. These levels of error are quite low considering the changing complexity of the growth media due to the shifting levels of amino acids, carbohydrates, yeastolate, proteins, and cell debris. This study represents an important step in the development of noninvasive on-line monitoring devices for cell culture bioreactors. PMID:18636439

Riley, M R; Rhiel, M; Zhou, X; Arnold, M A; Murhammer, D W

1997-07-01

105

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.

2011-02-01

106

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)

2001-06-01

107

Brain glucose concentrations in poorly controlled diabetes mellitus as measured by high-field magnetic resonance spectroscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hyperglycemia and diabetes alter the function and metabolism of many tissues. The effect on the brain remains poorly defined, but some animal data suggest that chronic hyperglycemia reduces rates of brain glucose transport and/or metabolism. To address this question in human beings, we measured glucose in the occipital cortex of patients with poorly controlled diabetes and healthy volunteers at the same levels of plasma glucose using proton magnetic resonance spectroscopy. Fourteen patients w...

2005-01-01

108

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

109

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

International Nuclear Information System (INIS)

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

1986-01-01

110

Measurement of oxygen transfer properties using oxidation of glucose with air catalyzed by glucose oxidase. Glucose oxidase ni yoru glucose no kuki sanka wo mochiiru sanso ido tokusei no sokutei  

Energy Technology Data Exchange (ETDEWEB)

It is essential to know the accurate values of the gas-liquid oxygen transfer coefficient k{sub La} and liquid-solid oxygen transfer coefficient k{sub s} to design a bioreactor. A method to determine these coefficients was studied in this paper by using oxidation of glucose with air catalyzed by glucose oxidase (GO) and by measuring the steady-state dissolved oxygen concentration G{sub os} to develop a rapid and simple measuring method without receiving any influence of coexisting materials. Free GO and immobilized GO gel beads were employed respectively to determine k{sub La} and k{sub s} in the contactors which were a small scale aerated stirred cell and a bubble column with draft tube. The kinetic parameters for free GO were almost identical to those in the literatures. The difference in the values of k{sub La} between the enzymatic and physical methods was found to be attributable to foaming in the enzyme reaction medium. The determination of k{sub La} could be applied to the cultivation broths. On the other hand, accurate values of k{sub s} could be calculated by deriving the rate equation for theimmobilized GO gel beads. 20 refs., 8 figs., 3 tabs.

Nakao, K.; Fukunaga, K.; Yasuda, Y.; Kimura, M. (Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering); Furumoto, K. (Oshima National College of Maritime Technology, Yamaguchi (Japan)); Otani, S. (Mitsui Petrochemical Industries Ltd., Tokyo (Japan))

1991-07-10

111

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

112

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

Energy Technology Data Exchange (ETDEWEB)

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

Schelbert, H.R.; Phelps, M.E.

1980-06-01

113

Effects of beraprost sodium, a prostaglandin I(2) analog, on high glucose-induced proliferation and oxidative stress in a rat glomerular mesangial cell line.  

Science.gov (United States)

To investigate the effects of beraprost sodium on the proliferation and oxidative stress of glomerular mesangial cells under high glucose conditions, a rat mesangial cell line (rat mesangial cells; RMCs) was treated with beraprost sodium in the presence of high glucose concentrations. Proliferation rates of mesangial cells were detected by MTT assays and BrdU incorporation analyses. Levels of reactive oxygen species (ROS) were detected by DCFH-DA probes. The mRNA expression levels of CuZnSOD, MnSOD, catalase (CAT), glutathione peroxidase (Gpx), and collagen IV were detected by RT-PCR, and the protein levels of antioxidants (i.e. CuZnSOD, CAT, and MnSOD) and collagen IV were detected by Western blot. Beraprost sodium treatment significantly decreased the proliferation and ROS levels of RMCs cultured in high glucose conditions in a dose-dependent manner (p Beraprost sodium treatment decreased the mRNA and protein levels of CuZnSOD, CAT, and collagen IV in cells under high glucose conditions, while it increased MnSOD protein levels in cells under normal glucose conditions. Therefore, beraprost sodium inhibits high glucose-induced cellular proliferation and the generation of ROS, and it improves the antioxidant capacities of rat glomerular mesangial cells. PMID:21646820

Zhang, Lan-Yu; Zou, Jun-Jie; Liu, Zhi-Min

2011-01-01

114

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

Directory of Open Access Journals (Sweden)

Full Text Available

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

 

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

 

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

 

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

R Rasouli

2012-05-01

115

A fluorescent compound for glucose uptake measurements in isolated rat cardiomyocytes.  

Science.gov (United States)

A focus of current diabetes research is the development of insulinomimetic compounds for oral treatment of diabetes and its associated cardiac complications. Screening compounds for their potential insulinomimetic effects usually involves the use of radioactive isotopes. The focus of this study was to investigate a nonradioactive fluorescent compound for its use in screening insulinomimetic compounds. The indicator 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) has been used by some workers to measure glucose uptake in Escherichia coli and Candida albicans. We propose that 2-NBDG will also be a suitable indicator for mammalian cell lines, in particular rat cardiomyocytes. We found that the indicator could give a reliable reproducible standard curve following appropriate dilution and is taken up by isolated cardiomyocytes. The insulinomimetic compounds vanadyl sulfate and sodium molybdate showed rates of glucose uptake similar to that of insulin. Furthermore, the rate of uptake measured for insulin using this technique (0.04 +/- 0.003 nmol x min(-1) x 10(6) cells(-1) is comparable with previous literature using 2-deoxyglucose uptake measurements on isolated myocytes (0.040 nmol x min(-1) x 10(6) cells(-1), demonstrating the validity of this fluorescent compound for glucose uptake studies. PMID:11991231

Ball, S W; Bailey, J R; Stewart, J M; Vogels, C M; Westcott, S A

2002-03-01

116

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

Energy Technology Data Exchange (ETDEWEB)

[{sup 18}F]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<0.05). Although no systematic deviations were noted in K{sup *}{sub 1} or rCMRglc, there were small deviations in K{sup *} (less than 10%) and LC (less than 5%) with a statistical significance (p<0.01). The deviation between the measurements in K{sup *} 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)

Nishizawa, Sadahiko; Ueno, Makoto; Shimono, Taro; Toyoda, Hiroshi; Konishi, Junji [Kyoto Univ. (Japan). Graduate School of Medicine; Kuwabara, Hiroto

2001-06-01

117

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

118

Reliability of visual analog and verbal descriptor scales for "objective" measurement of temporomandibular disorder pain.  

Science.gov (United States)

Eight dentists viewed standardized videotapes showing palpations of the temporomandibular joint and muscles of mastication and recorded their judgments concerning the amount of pain the patient was experiencing. Judgments were recorded using a four-point verbal descriptor scale (VDS) ("none", "mild", "moderate", "severe" pain) or a 100-mm visual analog scale (VAS) anchored with the terms "no pain" and "worst pain possible". Test/re-test reliability over a one-week period and interjudge reliabilities were calculated for each scale; reliabilities of the two scales were directly compared based on the statistical equivalence of weighted kappa and the Intraclass Correlation Coefficient. Neither scale showed satisfactory reliability. Median test/re-test reliabilities were k = 0.590 for the VDS and r = 0.822 for the VAS. Interjudge reliabilities averaged k = 0.394 for the VDS and r = 0.735 for the VAS. Direct comparison of reliabilities for the two scales showed no clear advantage for either scale. The marginal reliabilities of these scales, when used by dentists to quantify the patient's pain, suggest that neither scale should be regarded as an "objective" pain measure. PMID:11039041

Le Resche, L; Burgess, J; Dworkin, S F

1988-01-01

119

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

International Nuclear Information System (INIS)

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

1993-01-01

120

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.)

1998-03-01

 
 
 
 
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

Simultaneous measurement of blood flow and glucose metabolism by autoradiographic techniques  

International Nuclear Information System (INIS)

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

1981-01-01

123

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

Directory of Open Access Journals (Sweden)

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

Junfeng Li

2008-05-01

124

Optical Rotatory Dispersion Measurement of D-Glucose with Fixed Polarizer Analyzer Accessory in Conventional Spectrophotometer  

Directory of Open Access Journals (Sweden)

Full Text Available In the sample compartment of a conventional spectrophotometer, mounting of a polarizer before sample and an analyzer behind sample allows the determination of the optical rotatory dispersion of optical active media by measurement of the transmission ratio of crossed and parallel arranged polarizer and analyzer. A formula for the determination of the angle of rotation is derived from the transmission ratio. The arrangement is applied to determine the molar optical rotation of D-glucose in water in the wavelength range from 220 nm to 820 nm.

Alfons Penzkofer

2013-10-01

125

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)

1985-01-01

126

Effects of detection geometry on polarimetric measurements of scattered light from turbid media containing optically active glucose molecules  

Science.gov (United States)

The effects of optically turbid medium on polarization states of incident light are studied using a novel linear Stokes polarimeter. The optical rotation and surviving linear polarization fraction of light scattered from highly turbid media (scattering coefficient ?s = 100 cm-1) are measured both in and off the incident plane while the detection angle changes from forward direction (0°) to backward directions (135°, 145° and 155°). The response of the optical rotation and surviving linear polarization to the presence of glucose molecules (0.06M - 0.9M) is also studied. The results show that in the absence of glucose, the scattering-induced optical rotation is zero in the incident plane for all detection angles, and increases with detection angle when measured off the incident plane. Conversely, the surviving linear polarization fraction increases with detection angle in the incident plane, and decreases when off the incident plane. Thus, when measured in the incident plane, optical rotation is least sensitive to glucose in the turbid medium, whereas the surviving linear polarization is most sensitive. For the above turbidity and glucose concentration ranges, the optimal glucose detection sensitivity using optical rotation is at 135° detection angle, 2 mm off the incident plane, while it is at 135° detection angle in the incident plane if surviving linear polarization is used as a glucose probe. This work demonstrates the complexity of polarimetry in turbid chiral media and underscores the importance of detection geometry in making and interpreting turbid polarimetry measurements.

Guo, Xinxin; Wood, Michael F. G.; Vitkin, I. A.

2005-09-01

127

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

Directory of Open Access Journals (Sweden)

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

Oddershede L

2014-01-01

128

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

129

AW ANALOG METHOD FOR MEASURING THE LONGITUDINAL COUPLING IMPEDANCE OF A RELATIVISTIC PARTICLE BEAM WITH ITS ENVIRONMNET  

Energy Technology Data Exchange (ETDEWEB)

The stability of a coasting beam against self-bunching (negative mass instability) may be expressed in terms of a beam coupling impedance. The impedance has contributions from self-fields, wall impedance, and curvature effects. This paper describes procedures for measuring the wall and curvature contributions to the coupling impedance by means of an analog in which the beam is replaced by a conductor propagating a TEM-like mode. Conditions are derived under which the measurements are valid, various measurement procedures are described and results of the application of the method to the compressor of an electron ring accelerator are reported.

Faltens, A.; Hartvig, E.C.; Mohl, D.; Sessler, A.M.

1971-08-01

130

Analysis of sensitivity and optical path-length in non-invasive measurement of glucose with near infrared spectroscopy  

Science.gov (United States)

Non-invasive glucose monitoring with optical methods has obtained increasing interest, in that the methods have shown great benefit for diabetes. Nevertheless, low sensitivity and signal to noise ratio (ratio of effective photons) are two major difficulties in non-invasively NIR spectral monitoring of blood glucose concentration. Designing the optical probe properly is one of the effective ways to improve measuring sensitivity and ratio of effective photons. In this paper, definition about ratio of effective photons in measurement of glucose is introduced. And then effect of glucose on optical properties of human skin is analyzed, based on this, two kind of sensitivities for diffuse reflectance, namely sensitivity to absorption and that to scattering, is derived. To investigate the ratio of effective photons and sensitivities, Monte Carlo simulations have been performed on a three-layered media with optical parameters similar to those of human skin. The results have shown that (1) high ratio of effective photons, even as high as 60%, can be obtained by choosing proper the separation between source and detector; (2) sensitivity of diffuse reflectance to absorption and scattering has different dependence on source-detector separation, which enables one can have different options by making use of different effect from glucose level changing. In the end, some suggestions have been put forward to improve precision of measurement of blood glucose.

Luo, Yunhan; Liu, Rong; Chen, Wenliang; Cui, Houxin; Xu, Kexin

2005-03-01

131

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

132

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

Science.gov (United States)

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

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

2004-06-01

133

Development of a rapid method for the measurement of lactose in milk using a blood glucose biosensor.  

Science.gov (United States)

Current methods for lactose measurement in dairy products are time consuming and tedious and may require expensive equipment and skilled technicians. The aim of this research was to develop a novel and rapid method for the routine measurement of lactose in dairy products. The proposed method is based on the rapid hydrolysis of lactose using ?-galactosidase and subsequently measuring glucose using a blood glucose meter. Blood glucose meters were developed after decades of research and clinical trials and are used extensively worldwide by individuals with diabetes to monitor their blood glucose levels. The method was developed and validated in a series of experiments. In the first experiment, temperature and time required for the near-complete hydrolysis of lactose were determined. Subsequently, the influence of glucose meters and their test strip lots were evaluated. We found that meters were not significantly different. However, the test strip lots were significantly different from each other. In the second experiment, the proposed method was validated using different concentrations of lactose solutions (1.9-6.5%) and compared with a HPLC-based reference method. In the third experiment, the proposed method was used to determine the lactose content of raw milk. The proposed method shows potential for rapid, routine, and low-cost measurement of lactose in milk and other dairy products. PMID:21943731

Amamcharla, J K; Metzger, L E

2011-10-01

134

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

Science.gov (United States)

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

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

2014-08-01

135

Dual-analyte fiber-optic sensor for the simultaneous and continuous measurement of glucose and oxygen.  

Science.gov (United States)

A fiber-optic sensor for the continuous and simultaneous determination of glucose and oxygen is described. The sensor is comprised of dual-analyte sensing sites in defined positions on the distal end of an imaging fiber (350 microns o.d.). Each sensing site is an individual polymer cone covalently attached to the activated fiber surface using localized photopolymerization. The oxygen sensor consists of a double-layer polymer cone. The inner polymer cone is a hydrophobic gas-permeable copolymer containing an oxygen-sensitive ruthenium dye, and the outer layer is a poly(hydroxyethyl methacrylate) (HEMA) polymer. The glucose sensor is an oxygen sensor with a poly-HEMA outer layer containing immobilized glucose oxidase. The fluorescence images of both sensing sites are captured with a CCD camera, and the measured fluorescence intensities are related to analyte concentrations. Oxygen quenching data for both sensing sites fit a two-site Stern-Volmer quenching model. The sensor has been used to simultaneously monitor independent changes in glucose and oxygen concentrations. Glucose calibration curves were obtained under varying oxygen tensions, and the detection limit is 0.6 mM glucose. The effect of fluctuations in oxygen partial pressure on the glucose response can be used to calibrate the sensor. The sensor response time varies from 9 to 28 s, depending on the different thicknesses of the enzyme layer. The sensor maintains the same sensitivity for 2 days. Multiple glucose sensing sites with different enzymatic activities can be immobilized on the distal end of the fiber, affording control of the linear range. PMID:8644922

Li, L; Walt, D R

1995-10-15

136

Plasma glucose measurement in diabetes: impact and implications of variations in sample collection procedures with a focus on the first hour after sample collection.  

Science.gov (United States)

Abstract Background: Previous studies of participants with plasma glucose concentrations at or near the glucose reference range demonstrate glucose loss following delayed separation and extraction of plasma from the cellular components of blood, of ?7% per hour. We aimed to assess pre-analytical glucose loss in diabetic subjects, focusing on the first hour after sample collection. Methods: Venous blood was collected from diabetes clinic attendees, into a series of lithium heparin PST™ (plasma separator tube) and fluoride oxalate Vacutainers™. Baseline (reference) plasma glucose measurements were undertaken on samples prepared under refrigerated conditions. The remaining samples underwent a series of controlled pre-analytical delays in sample preparation, at room temperature. Plasma glucose was measured using the hexokinase method. Results: Median baseline glucose (mmol/L) for the 62 participants was 10.6 (range 3.4-31.1). Using lithium heparin PST™ tubes, mean glucose loss (95% CI) was 0.16 (0.09-0.23) after 30 min delay in plasma preparation and 0.28 (0.21-0.34) after 60 min delay. Glucose loss was independent of both baseline glucose and also individual cellular count. Fluoride failed to inhibit glucose loss within the first hour after sample collection. Immediate plasma centrifugation of PST™ tubes, followed by delayed plasma extraction (median delay 92 min), produced a mean glucose loss of 0.02 mmol/L (-0.05-0.09). Conclusions: Samples collected into lithium heparin PST™ tubes show pre-analytical glucose loss at 1 h that is independent of baseline glucose and cellular count. Furthermore, immediate plasma separation using these tubes attenuates glucose loss across a wide range of glucose concentrations. PMID:24706432

Chan, Huan; Lunt, Helen; Thompson, Harmony; Heenan, Helen F; Frampton, Christopher M A; Florkowski, Christopher M

2014-07-01

137

Noninvasive glucose measurement by fluorescence quenching of non toxic gold nanoparticles  

Science.gov (United States)

Effects of interaction of human body compatible gold nanoparticles with glucose on fluorescence emission spectra of the nanoparticles are investigated experimentally. It is observed that nanoparticles' fluorescence peak quenches and blue shifted because of such interaction. This procedure is sensitive even to low difference of glucose concentration. The results suggest that glucose could seriously affect the optical properties of gold nanoparticles. Furthermore, a linear range of relative shift of different fluorescence spectrum's peaks is obtained. Furthermore, comparison of fluorescence and absorption results shows that the former technique is as much as 20 times more sensitive to the variation of glucose concentration.

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

2014-06-01

138

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

Energy Technology Data Exchange (ETDEWEB)

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.) [Deutsch] Das Ziel unserer Studie war die Ueberpruefung der Reproduzierbarkeit dieser Methode und der Vergleich der diagnostischen Leistungsfaehigkeit dieses Verfahrens mit derjenigen der visuellen Analyse bei Patienten mit komplex partiellen Anfaellen (CPS). Der regionale zerebrale Glukoseverbrauch (rCMRGlc) wurde interiktal bei 25 CPS-Patienten und 10 Kontrollen mit 18-F-Fluorodeoxyglukose (FDG) und der PET-Kamera ECAT EXACT 47 gemessen. Die PET-Aufnahmen wurden visuell auf unilateralen temporalen Hypometabolismus hin beurteilt. Weiterhin wurde der rCMRGLc auf sechs koronaren Schichten mit Hilfe manuell gezeichneter Linienprofile quantifiziert. Aus diesen Profilen wurden Asymmetrieindizes (ASY) in vier temporalen Regionen berechnet und mit den 95%-Konfidenzintervallen des Kontrollkollektivs verglichen. Alle Analysen wurden unabhaengig von zwei Auswertern ohne Kenntnis der klinischen Daten ausgefuehrt. Die Uebereinstimmung zwischen den beiden Auswertern in Hinsicht auf die Fokus-Lateralisierung war 96% fuer die visuelle und 100% fuer die quantitative Analyse. Die Uebereinstimmung zwischen der visuellen und quantitativen war gut. (orig.)

Matheja, P.; Kuwert, T.; Schaefers, M.; Schaefers, K.; Schober, O. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Diehl, B.; Stodieck, S.R.G.; Ringelstein, E.B. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Neurologie; Schuierer, G. [Muenster Univ. (Germany). Inst. fuer Klinische Radiologie

1998-03-01

139

Variability in measurements of blood glucose response to foods in human subjects is not reduced after a standard breakfast.  

Science.gov (United States)

Measurements of blood glucose response to food are highly variable. We determined whether within-individual variability in data for blood glucose responses were reduced if individuals consumed a standard meal 2 hours before testing and investigated the effect of serving size. Blood glucose responses to muesli and macaroni cheese were determined in 13 individuals by taking 2 fasting capillary blood samples. Food was then consumed, and capillary blood samples were taken every 15 minutes for the first hour and every 30 minutes for the second hour. The incremental area under the blood glucose response curve was determined, and glycemic glucose equivalents (GGEs) were calculated. The GGE values were not significantly different whether the muesli and macaroni cheese were fed fasting or after a standard breakfast (29.2 vs 34.5 g for muesli and 11.0 vs 14.6 g for macaroni cheese). Within-individual coefficients of variation were not significantly different whether the food was consumed fasting or after a standard breakfast (24.9% and 32.5% for muesli and 38.1% and 59.4% for macaroni cheese). Differences in GGE between measured and estimated half serving size for macaroni cheese were 0.8 g (P = .6) and for muesli, 3 g (P = .2); for the double serving size for macaroni cheese, 1.7 g (P = .7); and for muesli, 6.7 g (P = .06). The GGE values for foods and variability in blood glucose response within individuals were not significantly different whether individuals fasted or consumed a standard breakfast before testing. However, blood glucose levels tended to differ significantly after consumption of the double serving size of muesli compared with other serving sizes. PMID:19410974

Wallace, Alison J; Eady, Sarah L; Willis, Jinny A; Scott, Russell S; Monro, John A; Frampton, Chris M

2009-04-01

140

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

2003-10-01

 
 
 
 
141

Experimental study for cancer diagnosis with positron-labeled fluorinated glucose analogs: ["1"8F]-2-fluoro-2-deoxy-D-mannose  

International Nuclear Information System (INIS)

"1"8F-2-fluoro-2-deoxy-D-glucose ("1"8F-FDG) and "1"8F-2-fluoro-2-deoxy-D-mannose ("1"8F-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 "1"8F-FDG/g and 2.65+-0.81% dose "1"8F-FDM/g at 60 min and remained relatively constant until 120 min. Blood clearance of both "1"8F-FDG and "1"8F-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 "1"8F-FDM clearly delineated the main tumor, central necrosis, and lymph node metastases. These data suggested that "1"8F-FDM, which is a by-product of "1"8F-FDG synthesis, was also an excellent cancer diagnostic agent as well as "1"8-F-FDG. This is not only a new feature of "1"8F-FDM, but also an economical improvement on cancer diagnosis by PET. (orig.)

1982-01-01

142

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)

2005-01-01

143

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

144

[Continuous glucose monitoring (CGM)].  

Science.gov (United States)

Self-monitoring of blood glucose (SMBG) is now commonly used as a tool to measure blood glucose levels of diabetic patients, as health insurance started to cover its cost for patients receiving insulin. However, SMBG is used to evaluate blood glucose levels at different time points, making it impossible to speculate on changes in blood glucose levels occurring before and after measurement. Currently, continuous glucose monitoring (CGM), which determines diurnal blood glucose patterns on a continuous basis, is being introduced into routine clinical diabetic care. CGM results sometimes show abnormal blood glucose variations or hypoglycemia after meals or during sleep, even if SMBG results show normal levels in the same patient. The identification of blood glucose variations is the main advantage of CGM. This study reviewed the characteristic of and methods for preventing hypo and hyperglycemia based on the pattern of blood glucose variations in type 1 and type 2 diabetes that was identified by the introduction of CGM. PMID:24724427

Tsujino, Daisuke; Utsunomiya, Kazunori

2014-01-01

145

Measurement and prediction axial distribution of immobilized glucose oxidase gel beads suspended in bubble column  

Energy Technology Data Exchange (ETDEWEB)

The axial distribution of gel beads suspended completely in a bubble column was measured by sampling the three-phase dispersion through a vertical pipe located at any height of the column axis under various operating conditions of superficial gas velocity U{sub G}, average gel beads holdup {epsilon}{sub S} and unaerated slurry height H{sub D}. The gel beads used were prepared by entrapping glucose oxidase as well as fine palladium particles within calcium alginate gel to catalyze the air oxidation of glucose for efficient production of calcium gluconate. The conventional sedimentation-diffusion model, which includes the gel beads dispersion coefficient E{sub P} and their setting velocity {nu}{sub P} to describe the axial distribution, is found to give unreasonable E{sub P} values being at least twice as high as than those predicted from the published correlations, and also twice as high as the estimated values of the liquid dispersion coefficient E{sub L} in the three-phase bubble column. This was assumed to be ascribed to the reduced apparent values of {nu}{sub p}, since the intrinsic E{sub P} value should be nearly equal to the E{sub L} value. In view of the fact that the gel bead has almost the same density as the liquid phase and the size is comparable to the mean bubble size, the model was modified by introducing an additional parameter, the rise velocity of the gel beads swarm u{sub m} representing an effect of rising air bubbles on settling gel beads. The values of u{sub m} were determined from the observed axial distributions by assuming that the E{sub P} values are given by the reported correlation of E{sub L} in suspension of the inert calcium alginate ge beads, and empirically correlated with U{sub G} and {epsilon}{sub S}. The axial distributions calculated from the modified model well agreed with the observed ones for the different H{sub D}. (author)

Nakao, K.; Harada, T.; Yasuda, Y. [Yamaguchi Univ., Yamaguchi (Japan). Dept. of Applied Chemistry and Chemical Engineering; Furumoto, K. [Oshima National College of Maritime Tech., Yamaguchi (Japan)

2000-10-01

146

Serum fructosamine concentration as measure of blood glucose control in type I (insulin dependent) diabetes mellitus.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Serum fructosamine activity was studied in 42 patients with type I (insulin dependent) diabetes mellitus and 30 non-diabetic volunteers as an index of blood glucose control. There was a significant correlation both between fructosamine and glycosylated haemoglobin values (r = 0.82) and between fructosamine and the fasting C peptide concentration (r = -0.81). Test results in 14 of the diabetics reflected the mean plasma glucose concentration calculated from 25 serial estimations in a single 24...

Baker, J. R.; Metcalf, P. A.; Holdaway, I. M.; Johnson, R. N.

1985-01-01

147

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

2010-04-01

148

Effects of zinc supplementation on the anthropometric measurements, lipid profiles and fasting blood glucose in the healthy obese adults.  

Science.gov (United States)

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. PMID:24312830

Payahoo, Laleh; Ostadrahimi, Alireza; Mobasseri, Majid; Khaje Bishak, Yaser; Farrin, Nazila; Asghari Jafarabadi, Mohammad; Mahluji, Sepide

2013-01-01

149

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

150

Investigation on how to choose measurement sites for non-invasive near-infrared blood glucose sensing  

Science.gov (United States)

With the changing of human diet and the future of an aging society, the number of diabetic patients is growing rapidly and steadily. The major therapeutic method to that disease is monitoring the blood glucose concentration frequently to adjust the dose of the drugs and insulin. In order to avoid the painful finger prick, we choose the ear lobe as a measurement site with finger as a reference. Firstly, we compare the blood glucose concentration results of ear lobe and finger during an oral glucose tolerance test, the results showed a good correlation of the two sites. Secondly, the three-layered skin structure of finger and ear lobe has been studied by using optical coherence tomography (OCT) technique. The result shows that the thickness of each layer at ear lobe is thinner. Finally, the difference between reflectance spectra of finger and ear lobe is compared due to the diverse skin thickness. The results still show a higher absorbance value for ear lobe. In conclusion, the ear lobe is an ideal measurement site for noninvasive blood glucose sensing.

Jiang, Jingying; Zou, Da; Min, Xiaolin; Ma, Zhenhe; Xu, Kexin

2012-02-01

151

Continuous Glucose Monitoring  

Science.gov (United States)

... drop of blood, put the blood on a test strip, and insert it in a glucose meter. CGM, though, measures glucose in the interstitial fluid—the fluid between body cells just under the skin. People with ... of blood glucose tests to make decisions about food, medicines, and exercise. ...

152

Fluorescent microplate cell assay to measure uptake and metabolism of glucose in normal human lung fibroblasts.  

Science.gov (United States)

This is the first report of a fluorimetric microplate assay to assess glucose uptake and metabolism in eukaryotic cells. The assay was carried out incubating normal human lung fibroblasts in the wells of microtiter trays with a fluorescent D-glucose derivative, 2-N-7-(nitrobenz-2-oxa-1,3-diazol-4-yl)amino-2-deoxy-D-glucose (2-NBDG). This dye could be incorporated by glucose transporting systems in living cells. Substrate uptake was determined by analysing the data obtained with a fluorescence microplate reader. Variables studied in the development of the assay included dye concentration and incubation period. We found that this cell assay is very sensitive, reproducible, provides fast results and graphical display of data. It requires small sample volumes and allows handling of a large number of samples simultaneously. Okadaic acid was used to assess this microplate assay in the field of cytotoxicity. This diarrhetic shellfish toxin is a tumour promoter and a specific inhibitor of protein phosphatases 1 and 2A. The exposition of cells to okadaic acid (0.1 nM-1 microM) at different time intervals causes a decrease in intracellular glucose (40-50% over controls). Results obtained with okadaic acid are the starting point to evaluate application of the method to routine toxicity probes. PMID:12020600

Leira, F; Louzao, M C; Vieites, J M; Botana, L M; Vieytes, M R

2002-06-01

153

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

154

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1998-01-01

155

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

156

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.)

2002-05-01

157

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

Energy Technology Data Exchange (ETDEWEB)

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 K{sub i} was assessed. In nine additional patients, K{sub i} obtained with continuous sampling of AVB was compared with K{sub i} 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 K{sub i}. 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.)

Weerdt, Arno P. van der; Klein, Lucas J.; Visser, Cees A.; Visser, Frans C. [Department of Cardiology, University Medical Centre, Amsterdam (Netherlands); Lammertsma, Adriaan A. [PET Centre, Institute for Cardiovascular Research-VU (ICaR-VU), VU University Medical Centre, Amsterdam (Netherlands)

2002-05-01

158

Measurement of GLP-1 in Impaired Glucose Tolerance Subjects in Comparison to Type 2 Diabetes Patients and Healthy Subjects  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Incretin therapy of type 2 diabetes patients is based on the fact that Incretin Effect is diminished in those patients. The objective is to measure glucagon-like peptide-1 (GLP-1 levels in impaired oral glucose tolerance (IGT subjects and compare them to those of type 2 diabetes patients and healthy subjects. If the incretin hormone (GLP-1 is established to be diminished in IGT subjects, future study may assess effectiveness of incretin therapy to prevent or delay diabetes in IGT subjects. Patients and methods: GLP-1 was measured by ELISA test at 0, 30 and 120 minutes in accordance with OGTT in three groups: type 2 diabetes groups including 24 patient, impaired glucose tolerance group including 24 subject and healthy control group including 24 subject as control. Patients were classified according to the WHO criteria for diabetes diagnosis. Results: Fasting GLP-1 levels were none significantly different between the studied groups. One the other hand, GLP-1 response at 30' was significantly diminished in diabetics when compared with IGT and controls. GLP-1 levels at 120' were significantly reduced in type 2 diabetes patients when compared with IGT and controls and significantly diminished in IGT when compared with controls. Conclusions: The study indicates that the GLP-1 levels are diminished in impaired glucose tolerance subjects when it’s compared to normal subjects.

Ahmed Abdullah Ebeid

2013-10-01

159

Rapid, transient drop in brain glucose after intravenous phloretin or 3-0-methyl-D-glucose.  

Science.gov (United States)

Rats were injected intravenously with either phloretin (100 mg/kg) or 3-0-methyl glucose (2 g/kg) to reduce the carrier-mediated flux of glucose into brain. Plasma glucose and brain free glucose (BFG), lactate, and glycogen were measured over a 16 min time course. Injection of these substances caused a rapid drop in BFG to 60% of control at one minute and a minimum (50% of control values) at 4 min., followed by a gradual rise to control levels at 16 min. While plasma glucose fell, and then increased after injection, brain lactate and glycogen content was unaffected. Repeated injections of phloretin eventually caused a drop in brain glycogen; but with either competitor, BFG never fell below 50% of normal values. The i.v. injection of the glucose analog, 3-0-methyl glucose (the less toxic of the two drugs) is proposed as a possible means of cutting off the potentially hazardous supply of blood glucose to the postischemic brain. PMID:6658907

Oldendorf, W H; Crane, P D; Lawner, P M; Braun, L D

1983-01-01

160

Demonstration of remote optical measurement configuration that correlates to glucose concentration in blood  

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An optical approach allowing the extraction and the separation of remote vibration sources has recently been proposed. The approach has also been applied for medical related applications as blood pressure and heart beats monitoring. In this paper we demonstrate its capability to monitor glucose concentration in blood stream. The technique is based on the tracking of temporal changes of reflected secondary speckle produced in human skin (wrist) when being illuminated by a laser beam. A tempora...

Beiderman, Yevgeny; Blumenberg, Raz; Rabani, Nir; Teicher, Mina; Garcia, Javier; Mico, Vicente; Zalevsky, Zeev

2011-01-01

 
 
 
 
161

Measurement of proliferation and disappearance of rapid turnover cell populations in human studies using deuterium-labeled glucose.  

Science.gov (United States)

Cell proliferation may be measured in vivo by quantifying DNA synthesis with isotopically labeled deoxyribonucleotide precursors. Deuterium-labeled glucose is one such precursor which, because it achieves high levels of enrichment for a short period, is well suited to the study of rapidly dividing cells, in contrast to the longer term labeling achieved with heavy water ((2)H(2)O). As deuterium is non-radioactive and glucose can be readily administered, this approach is suitable for clinical studies. It has been widely applied to investigate human lymphocyte proliferation, but solid tissue samples may also be analyzed. Rate, duration and route (intravenous or oral) of [6,6-(2)H(2)]-glucose administration should be adapted to the target cell of interest. For lymphocytes, cell separation is best achieved by fluorescence activated cell sorting (FACS), although magnetic bead separation is an alternative. DNA is then extracted, hydrolyzed enzymatically and analyzed by gas chromatography mass spectrometry (GC/MS). Appropriate mathematical modeling is critical to interpretation. Typical time requirements are as follows: labeling, 10-24 h; sampling, approximately 3 weeks; DNA extraction/derivatization, 2-3 d; and GC/MS analysis, approximately 2 d. PMID:19696750

Macallan, Derek C; Asquith, Becca; Zhang, Yan; de Lara, Catherine; Ghattas, Hala; Defoiche, Julien; Beverley, Peter C L

2009-01-01

162

Analog multivariate counting analyzers  

International Nuclear Information System (INIS)

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 from dead time effects, and allow substantial reduction of pileup effects. Besides extending the scope of counting measurements, analog multivariate counting analyzers allow simple feedback adjustment of the parameters of the acquisition system for optimal performance. In addition, such analyzers can be made simpler, cheaper, lighter, more reliable, more accurate, and less power consuming than digital counting detectors, and thus would be ideally suited for operation in autonomous conditions such as mobile communication, space missions, prosthetic devices, etc. Other obvious immediate applications of the presented analyzers are pulse-height measuring systems used in the acquisition of nuclear radiation spectra

2003-01-11

163

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

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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

164

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.)

1985-01-01

165

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

Energy Technology Data Exchange (ETDEWEB)

C/sup 15/O/sub 2/ and /sup 15/O/sub 2/ 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 ..mu..mol/min/100 cc for normal tissue and 39.7 +- 20.1 ..mu..mol/min/100 cc for tumour surface. /sup 18/F-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 ..mu..mol/min/100 cc for normal muscle and 53.8 +- 18.3 ..mu..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.

Kairento, A.L.; Brownell, G.L.; Elmaleh, D.R.; Swartz, M.R. (Massachusetts General Hospital, Boston (USA). Physics Research Lab.)

1985-07-01

166

Glucose Sensing  

CERN Multimedia

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

167

Specific binding assays employing label analog to reduce sample interferences  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a homogeneous apoenzyme reactivation immunoassay method for determining an analyte in a test sample suspected to contain a potentially interfering binding substance. The test sample is combined with a reagent system that includes (i) a labeled reagent comprising a flavin adenine dinucleotide (FAD) label portion and a specific binding portion comprising the analyte or a binding analog thereof, (ii) an antibody capable of binding the analyte, and (iii) apoglucose oxidase, thereby forming a reaction mixture comprising an antibody bound-species and a free-species of the FAD-labeled reagent. The ability of the FAD-label portion of the labeled reagent to combine with the apoglucose oxidase to produce the catalytically active holoenzyme glucose oxidase is measurably different when the FAD-labeled reagent is in the bound-species compared to when in the free-species. The potentially interfering binding substance is capable of binding with the FAD-labeled portion of the labeled reagent. The glucose oxidase activity in the reaction mixture is measured and related to the amount of analyte in the test sample. The improvement consists of adding to the reaction mixture a flavin structural analog of FAD which does not significantly combine with apoglucose oxidase to produce active glucose oxidase but which binds with the potentially interfering FAD-binding substance.

Ledden, D.J.; Schroedter, D.E.

1989-03-07

168

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

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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

169

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.)

1988-01-01

170

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

2007-03-01

171

Kinetics of Sugar Transport and Phosphorylation Influence Glucose and Fructose Cometabolism by Zymomonas mobilis  

Science.gov (United States)

The competitive inhibition of fructokinase by glucose has been proposed as the mechanism by which Zymomonas mobilis preferentially consumes glucose from mixtures of glucose and fructose and accumulates fructose when growing on sucrose. In this study, incorporation of radioactive fructose into biomass was used as a measure of fructose catabolism. It was determined that the rate of fructose incorporation by Z. mobilis CP4 was somewhat lower in the presence of an equimolar concentration of glucose but that the inhibition of fructokinase by glucose was not nearly as severe in vivo as was predicted from in vitro studies. Interestingly, addition of glucose to a culture of Z. mobilis CP4-M2, a glucokinaseless mutant, resulted in an immediate and nearly complete inhibition of fructose incorporation. Furthermore, addition of nonmetabolizeable glucose analogs had a similar effect on fructose catabolism by the wild-type Z. mobilis CP4, and fructose uptake by Z. mobilis CP4-M2 was shown to be severely inhibited by equimolar amounts of glucose. These results suggest that competition for fructose transport plays an important role in preferential catabolism of glucose from sugar mixtures. Indeed, the apparent K(infm) values for sugar uptake by Z. mobilis CP4 were approximately 200 mM for fructose and 13 mM for glucose. Other experiments supported the conclusion that a single facilitated diffusion transport system, encoded by the glf gene, is solely responsible for the uptake of both glucose and fructose. The results are discussed with regard to the hypothesis that the kinetics of sugar transport and phosphorylation allow the preferential consumption of glucose and accumulation of fructose, making the fructose available for the enzyme glucose-fructose oxidoreductase, which forms sorbitol, an important osmoprotectant for Z. mobilis when growing in the presence of high sugar concentrations.

Parker, C.; Peekhaus, N.; Zhang, X.; Conway, T.

1997-01-01

172

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

173

Correlation of fasting blood glucose and haemoglobin A1c measured with an automated analyser  

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A subtype of glycohaemoglobin, haemoglobin (Hb) A1c, in specimens of whole blood was assayed on a new automated analyser that makes use of high-pressure liquid chromatography. The analyser provided precise and reproducible values. The mean of the HbA1c values was lower than that with an older instrument. The mean tended to increase with the age of the subjects, who were undergoing routine health examinations. No sex difference was found. When measurement was made 1 h after the subjects drank ...

1990-01-01

174

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

Directory of Open Access Journals (Sweden)

Full Text Available 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-thalassemia (21 female and 12 male cases. The following biochemical measurements were done: blood glucose level through biochemical glucose oxidation method, fructosamine by colorimetry, hemoglobin A1c by immunoturbidimetry, serum ferritin by chemiluminescence and fetal hemoglobin by HPLC methods. Using SPSS software v18.0, statistical analysis was done and correlation between fructosamine and hemoglobin A1c (Pearson’s correlation and linear regression were investigated. p<0.05 was considered as statistically significant.Results: In female and male patients, blood glucose levels were 204±103 mg/dL and 224±101 mg/dL (p=0.63, fetal hemoglobin were 9%±7% and 13%±9% (p=0.22; serum ferritin levels were 1744±1534 ng/mL and 3253±1773 ng/mL (p=0.96, respectively. Mean serum fructosamine level was 442±124 mmol/L and glycosylated hemoglobin amount was 8.9%±1.8%. These two parameters showed significant correlation (r=0.69, p<0.01. Blood glucose level with hemoglobin A1c (r=0.75, p<0.01 and fructosamine (r=0.54, p<0/01 showed a significant correlation.Conclusion: In diabetic patients with thalassemia major who have frequent blood transfusion, evaluation of serum fructosamine and glycosylated hemoglobin levels are both reliable approaches for estimating blood glucose levels and the two methods can be used alternatively.

Mehrnoush Kosaryan

2012-11-01

175

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 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)

2007-11-01

176

On-line measurements of oscillating mitochondrial membrane potential in glucose-fermenting Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

We employed the fluorescent cyanine dye DiOC(2)(3) to measure membrane potential in semi-anaerobic yeast cells under conditions where glycolysis was oscillating. Oscillations in glycolysis were studied by means of the naturally abundant nicotinamide adenine dinucleotide (NADH). We found that the mitochondrial membrane potential was oscillating, and that these oscillations displayed the same frequency and duration as the NADH oscillations. It was confirmed that DiOC(2)(3) localizes itself in the mitochondrial membrane and thus reports qualitative changes solely in mitochondrial membrane potential. Our studies showed that glycolytic oscillations perturb the mitochondrial membrane potential and that the mitochondria do not have any controlling effect on the dynamics of glycolysis under these conditions. Depolarization of the mitochondrial membrane by addition of FCCP quenched mitochondrial membrane potential oscillations and delocalized DiOC(2)(3), while glycolysis continued to oscillate unaffected.

Andersen, Ann Zahle; Poulsen, Allan K

2007-01-01

177

The A1chieve study: a 60 000-person, global, prospective, observational study of basal, meal-time, and biphasic insulin analogs in daily clinical practice.  

Science.gov (United States)

While evidenced-based guidelines promote glycated hemoglobin (HbA(1c)) targets <7.0% in order to reduce the long-term risk of diabetic complications, many individuals with type 2 diabetes do not achieve these targets. Fear of hypoglycemia provides a major barrier to improving blood glucose control as a result of delayed insulin initiation and failure to appropriately titrate insulin following initiation. Modern insulin analogs were designed to achieve improved blood glucose control with similar hypoglycemic risk compared with non-analog insulins (or similar blood glucose control with reduced hypoglycemic risk). While this has been demonstrated in randomized controlled trials, there is a need to confirm these findings in an everyday clinical setting. The A(1)chieve study will evaluate adverse events and effectiveness of premix (biphasic insulin aspart 30 [NovoMix 30]), basal (insulin detemir [Levemir]), and meal-time (insulin aspart [NovoRapid]) insulin analogs in people with type 2 diabetes in near-routine clinical practice. A(1)chieve is an international, prospective, multi-center, open-label, non-interventional, 24-week study of people with type 2 diabetes using an insulin analog. The study will recruit 60 000 people from 30 countries across four continents (Asia, Africa, South America, and Europe). The primary aim of the study is to assess the adverse event profile of the study insulins in routine clinical practice, including rates of hypoglycemia. In addition, effectiveness (HbA(1c), fasting plasma glucose, and postprandial plasma glucose) and patient quality of life outcomes will be measured. Comprehensive epidemiological data will be collected at baseline, including recent plasma glucose results and hypoglycemic episodes, prevalence of diabetes-related complications, and measures of current standards of care. Thus, A(1)chieve should provide important information about how insulin analogs perform in daily clinical practice. PMID:20466163

Shah, Siddharth N; Litwak, León; Haddad, Jihad; Chakkarwar, Praful N; Hajjaji, Issam

2010-05-01

178

2-Deoxyglucose incorporation into rat brain glycogen during measurement of local cerebral glucose utilization by the 2-deoxyglucose method  

Energy Technology Data Exchange (ETDEWEB)

The incorporation of 14C into glycogen in rat brain has been measured under the same conditions that exist during the measurement of local cerebral glucose utilization by the autoradiographic 2-(14C)deoxyglucose method. The results demonstrate that approximately 2% of the total 14C in brain 45 min after the pulse of 2-(14C)deoxyglucose is contained in the glycogen portion, and, in fact, incorporated into alpha-1-4 and alpha-1-6 deoxyglucosyl linkages. When the brain is removed by dissection, as is routinely done in the course of the procedure of the 2-(14C)deoxyglucose method to preserve the structure of the brain for autoradiography, the portion of total brain 14C contained in glycogen falls to less than 1%, presumably because of postmortem glycogenolysis which restores much of the label to deoxyglucose-phosphates. In any case, the incorporation of the 14C into glycogen is of no consequence to the validity of the autoradiographic deoxyglucose method, not because of its small magnitude, but because 2-(14C)deoxyglucose is incorporated into glycogen via (14C)deoxyglucose-6-phosphate, and the label in glycogen represents, therefore, an additional ''trapped'' product of deoxyglucose phosphorylation by hexokinase. With the autoradiographic 2-(14C)deoxyglucose method, in which only total 14C concentration in the brain tissue is measured by quantitative autoradiography, it is essential that all the labeled products derived directly or indirectly from (14C)deoxyglucose phosphorylation by hexokinase be retained in the tissue; their chemical identity is of no significance.

Nelson, T.; Kaufman, E.E.; Sokoloff, L.

1984-10-01

179

TD-1HNMR Measurements Show Enantioselective Dissociation of Ribose and Glucose in the Presence of H217O  

Science.gov (United States)

We used Time Domain 1H Nuclear Magnetic Resonance (NMR) to characterize changes in proton exchange between water and sugar enantiomers at different concentrations of H217O (~15-450 mM) and found that dissociation of the (-)-enantiomers of glucose and ribose occurs at significantly higher rates at higher concentrations of H217O. The mechanism behind this enantioselective effect is unclear. The hypothesis we propose is that the large magnetic field (Bo ~0.6T) applied during NMR measurements induces electric moments opposite in sign for the D and L-isomers. Because 17O has a nuclear electric quadrupole moment ? 0, asymmetrically hydrated complexes may form between the Bo-polarized enantiomers and H217O. Either H217O is more often hydrating the (+) than the (-)-enantiomers-and consequently pK differences between H216O and H217O lead to differences in proton exchange between enantiomers and water-or the orientation of H217O relative to the Bo-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.

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

2007-10-01

180

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

 
 
 
 
181

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

182

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

183

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

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

Fujii, S.; Beutler, E.

1985-01-01

184

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)

1990-01-01

185

Measurement of SFDR and noise in EDF amplified analog RF links using all-optical down-conversion and balanced receivers  

Science.gov (United States)

Optical down-conversion techniques have become an increasingly popular architecture to realize Multi-band Enterprise Terminals (MET), Synthetic Aperture Radar (SAR), Optical Arbitrary Waveform Generation (OAWG), RF Channelizers and other technologies that need rapid frequency agile tunability in the microwave and millimeter RF bands. We describe recent SFDR, NF, Gain, and Noise modeling and measurements of Erbium-doped-fiber amplified analog RF optical links implementing all-optical down-conversion and balanced photodiode receivers. We describe measurements made on our newly designed extensive test-bed utilizing a wide array of high powered single and balanced photodiodes, polarization preserving output LN modulators, EAMs, LIMs, tunable lasers, EDFAs, RF Amplifiers, and other components to fully characterize direct and coherent detection techniques. Additionally, we compare these experimental results to our comprehensive MATLAB system modeling and optimization software tools.

Middleton, Charles; Borbath, Michael; Wyatt, Jeff; DeSalvo, Richard

2008-05-01

186

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

International Nuclear Information System (INIS)

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

2002-01-01

187

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

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 ("1"8F)-2-deoxy-2-fluoro-D-glucose (FDG) and positron ECT. Our model incorporates a k_4* mediated hydrolysis of FDG-6-PO_4 to FDG which then competes with phosphorylation (k_3*) of FDG back to FDG-6-PO_4 and reverse transport (k_2*) back to blood. Although small, k_4* is found to be significant. The ECAT positron tomograph was used to measure the rate constants (k_1*?k_4*), lumped constant (LC), stability, and reproducibility of the model in man. Since these parameters have not been measured for FDG in any species, comparisons are made to values for DG in rat and monkey. Compartmental concentrations of FDG and FDG-6-PO_4 were determined and show that cerebral FDG-6-PO_4 steadily accumulates for about 100 mins, plateaus and then slowly decreases due to hydrolysis. Cerebral blood FDG concentration was determined to be a minor contribution to tissue activity after 10 min. Regional CMRGlu measurements are reproducible to +- 5.5% over 5 hrs. PT allows the in vivo study ofregional biochemistry and physiology in normal and pathophysiologic states in man with a unique and fundamental capability

1977-06-30

189

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.

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

190

Continuous Glucose Monitoring  

Science.gov (United States)

... of Topics and Titles : Continuous Glucose Monitoring Continuous Glucose Monitoring On this page: What is glucose monitoring? ... Hope through Research For More Information What is glucose monitoring? Glucose monitoring helps people with diabetes manage ...

191

Blood pressure measures and electrocardiogram-defined myocardial infarction in an Iranian population: Tehran Lipid and Glucose study.  

Science.gov (United States)

The purpose of this study was to describe blood pressure values in Iranian adults with electrocardiogram (ECG) evidence of a myocardial infarction (MI). High blood pressure is a risk factor, and an ECG can be diagnostic of coronary artery disease. In recent studies the role of pulse pressure in predicting coronary artery disease has been suggested to be more important than that of blood pressure. From among participants of the Tehran Lipid and Glucose study, data for 2479 men and 3060 women aged > or =30 years not currently using any antihypertensive medication were collected. The study used the mean of two separate blood pressure measurements for each individual. ECG findings of all subjects were coded according to Minnesota ECG coding criteria, and they were categorized into probable/possible MI or no MI. ECG evidence of probable or possible MI was found in 1.2% of subjects (1.8% in men vs. 0.8% in women, p<0.001). Prevalence of ECG-defined MI in hypertensive persons was two-fold higher than in normotensives. Adjusted for age, sex, and body mass index, mean diastolic blood pressure was significantly lower in cases with ECG-defined MI than in subjects without MI (p<0.03). There was a strong positive correlation between pulse pressure and systolic blood pressure in both hypertensive/normotensive and MI/no MI groups at the p<0.001 level. There was a weak inverse correlation between diastolic blood pressure and pulse pressure in hypertensive/normotensive/no MI groups (-0.32 and -0.14, both p<0.001). Diastolic blood pressure was not correlated with pulse pressure in cases with MI. Prevalence of ECG-defined MI in hypertensive cases was higher than in normotensives. Systolic blood pressure is a better predictor for pulse pressure than diastolic blood pressure in both normotensive and hypertensive populations with or without ECG-defined MI. PMID:14872144

Ghanbarian, Arash; Rashidi, Arash; Madjid, Mohammad; Azizi, Fereidoun

2004-02-01

192

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

2003-12-11

193

Glucose uptake rates of single E. coli cells grown in glucose-limited chemostat cultures.  

Science.gov (United States)

To evaluate the extent to which single-cell glucose uptake rates determine the overall specific growth rate of a culture, dilute chemostat cultures of Escherichia coli BL21 were grown in defined medium under glucose limitation. The glucose uptake dynamics of the cell population was examined at the single-cell level using the fluorescent glucose analog, 2-NBDG. Between dilution rates of 0.12 h(-1) and 0.40 h(-1), mean cellular protein content and steady-state, extracellular glucose concentrations increased with increasing dilution rate. However, the distribution of 2-NBDG uptake rates in the population remained constant over the range of dilution rates studied. This indicates that the growth of cells in continuous culture is not limited by the maximum rate of uptake of glucose but by the availability of glucose for transport. The work represents an example of how quantitative flow cytometry can be applied to gain detailed insight into microbial growth physiology. PMID:11000435

Natarajan, A; Srienc, F

2000-09-01

194

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

International Nuclear Information System (INIS)

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

2010-07-01

195

Intuitive analog circuit design  

CERN Multimedia

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

196

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

197

A simple visual analog scale for pain is as responsive as the WOMAC, the SF-36, and the EQ-5D in measuring outcomes of revision hip arthroplasty  

Science.gov (United States)

Background and purpose Little is known about the comparative performance of patient-reported outcome measures in revision hip arthroplasty. We compared the performance of the WOMAC, the SF-36, the EQ-5D, and a pain-related visual analog scale (VAS) in revision hip arthroplasty. Methods 45 patients with aseptic prosthetic loosening following primary hip arthroplasty completed the WOMAC, the SF-36, the EQ-5D, and a VAS for pain—at baseline and 2 years after revision. Responsiveness of the measures was compared with the effect size (with ? 0.8 being considered large). Agreement between scales measuring the same type of outcome (pain or physical function) was assessed with the Bland-Altman method. Results The mean preoperative scores for the pain and physical function scales of WOMAC and SF-36, EQ-5D index, and VAS for pain improved statistically significantly 2 years after revision. The effect size for the WOMAC pain was 1.7, that for SF-36 pain was 1.4, that for WOMAC physical function was 1.6, that for SF-36 physical function was 0.8, and that for EQ-5D index was 1.2. The VAS for pain had an effect size of 2.1, which was larger than that for SF-36 pain and for the EQ-5D index (p ? 0.03) but not for WOMAC pain (p = 0.2). The limits of agreement between WOMAC pain, SF-36 pain, and the VAS scale measuring pain—and between the WOMAC and SF-36 scales measuring physical function—were wide. Internal-consistency reliability was high for the WOMAC and SF-36 scales but low for the EQ-5D. Interpretation In patients with first-time revision hip arthroplasty done for aseptic loosening, the WOMAC, SF-36, and EQ-5D showed high responsiveness in measuring patient-reported outcomes and the simple VAS for pain performed equally well.

2014-01-01

198

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Evaluation of metabolic control of diabetic people has been classically performed measuring glucose concentrations in blood samples. Due to the potential improvement it offers in diabetes care, continuous glucose monitoring (CGM) in the subcutaneous tissue is gaining popularity among both patients and physicians. However, devices for CGM measure glucose concentration in compartments other than blood, usually the interstitial space. This means that CGM need calibration against blood glucose va...

Paolo Rossetti; Jorge Bondia; Josep Vehí; Fanelli, Carmine G.

2010-01-01

199

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 (?13CO2<-20%) and natural (?13CO2=-1 to -20%) sources. 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 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. 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

200

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

Energy Technology Data Exchange (ETDEWEB)

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.

Wajngot, A.; Khan, A.; Giacca, A.; Vranic, M.; Efendic, S. (Karolinska Hospital, Stockholm (Sweden))

1990-11-01

 
 
 
 
201

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

1990-01-01

202

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

203

Continuous monitoring of blood glucose.  

Science.gov (United States)

Continuous blood glucose monitoring aims to: better evaluate glycaemic variations; better detect hypoglycaemia; and, ultimately, automatize insulin delivery (artificial beta cell). The sensors can be fully implantable, with the challenge of constructing durable systems to avoid repeated implantations. In-dwelling needle-like electrodes and microdialysis fibres with a pump that brings the dialysate to the glucose sensor are inserted in the subcutaneous tissue through the skin. The GlucoWatch is an almost non-invasive technique that extracts the extracellular fluid by iontophoresis. In these systems, the glucose oxidase generates the electrical signal, proportional to the glucose concentration. Non-invasive techniques aim at measuring the glucose concentration without breaching the skin, using absorption of light in the infrared spectrum. These techniques have not reached the necessary reliability for use as glycaemic alarms, and even less as artificial beta cells. Currently, glucose sensors are mainly used as glycaemic holters to help in the management of insulin therapy. PMID:11979031

Robert, Jean-Jacques

2002-01-01

204

Glucose uptake-stimulatory activity of Tinospora cordifolia stem extracts in Ehrlich ascites tumor cell model system.  

Science.gov (United States)

Diabetes mellitus is a multifunctional disorder with several causes and multiple consequences. Nutraceuticals play a vital role in ameliorating diabetic condition. The stems of the plant, Tinospora cordifolia (T. cordifolia) are often used in Ayurvedic medicine for the management of diabetes. Earlier studies have shown that T. cordifolia to be a potent antidiabetic plant material by virtue of being rich in nutraceuticals. In the present study we were interested to know if, T. cordifolia stem extracts are able to promote glucose uptake through glucose transporters, 1 (GLUT1) and 3 (GLUT3), which are responsible for basal glucose uptake. Hence, Ehrlich ascites tumor (EAT) cells were chosen as a model which harbours both GLUT1 and GLUT3 and glucose uptake was measured using a fluorescent analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG). Serially, solvent extracted T. cordifolia stems, especially water, ethanol and methanol extracts showed glucose uptake activity. Uptake was stimulated in a dose dependent manner at dosages of 1-100 ?g. Glucose-stimulating activity does not seem to be solely due to polyphenol content since methanol extract, with high amount of polyphenol content (9.5?±?0.1 g?kg(-1)), did not stimulate higher glucose uptake activity when compared to water extract. PMID:24426067

Joladarashi, Darukeshwara; Chilkunda, Nandini D; Salimath, Paramahans Veerayya

2014-01-01

205

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

1990-01-01

206

Stimulation of glucose uptake and improvement of insulin resistance by aromadendrin.  

Science.gov (United States)

Agents that stimulate glucose uptake and improve insulin resistance may be useful in the management of type 2 diabetes mellitus (DM). Thus, the aims of this study were to assess the effects of aromadendrin, a flavonoid from Gleditsia sinensis Lam., on stimulation of glucose uptake and improvement of insulin resistance and to characterize the molecular mechanisms underlying these activities. Insulin-stimulated glucose uptake was measured in HepG2 cells and in differentiated 3T3-L1 adipocytes using 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG), a fluorescent D-glucose analog. Expression of the peroxisome proliferator-activated receptor-?2 (PPAR?2) and adipocyte-specific fatty acid binding protein (aP2) mRNAs and the PPAR?2 protein was analyzed in adipocytes using RT-PCR and immunoblotting, respectively. Insulin-stimulated protein kinase B (Akt/PKB) phosphorylation was measured in high glucose-induced, insulin-resistant HepG2 cells. Similar to 30 ?mol/l rosiglitazone, treatment with 30 ?mol/l aromadendrin significantly stimulated insulin-sensitive glucose uptake in both HepG2 cells and 3T3-L1 adipocytes. Aromadendrin treatment also enhanced adipogenesis and caused increases in the expression of PPAR?2 and aP2 mRNAs and the PPAR?2 protein in differentiated 3T3-L1 adipocytes. In high glucose-induced, insulin-resistant HepG2 cells, aromadendrin reversed the inhibition of Akt/PKB phosphorylation in response to insulin, which could be abrogated by pretreatment with LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor. Aromadendrin treatment induced adipogenesis by increases in PPAR?2 expression, resulting in stimulation of glucose uptake and ameliorated insulin resistance. These findings suggest that aromadendrin may represent a potential therapeutic candidate for the management of type 2 DM. PMID:22056597

Zhang, Wei Yun; Lee, Jung-Jin; Kim, In-Su; Kim, Yohan; Myung, Chang-Seon

2011-01-01

207

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

Energy Technology Data Exchange (ETDEWEB)

This improved isotope-dilution gas chromatographic/mass spectrometric (GC/MS) method, in which (/sup 13/C)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 (/sup 13/C)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.

Pelletier, O.; Arratoon, C.

1987-08-01

208

Structured Analog CMOS Design  

CERN Multimedia

Structured Analog CMOS Design describes a structured analog design approach that makes it possible to simplify complex analog design problems and develop a design strategy that can be used for the design of large number of analog cells. It intentionally avoids treating the analog design as a mathematical problem, developing a design procedure based on the understanding of device physics and approximations that give insight into parameter interdependences. The proposed transistor-level design procedure is based on the EKV modeling approach and relies on the device inversion level as a fundament

Stefanovic, Danica

2008-01-01

209

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

210

Effects of sitagliptin or mitiglinide as an add-on to acarbose on daily blood glucose fluctuations measured by 72 h subcutaneous continuous glucose monitoring in Japanese patients with type 2 diabetes: a prospective randomized study.  

Science.gov (United States)

Objective: Postprandial hyperglycemia and blood glucose fluctuations increase the risk of macroangiopathy in patients with type 2 diabetes mellitus (T2DM). However, few studies have examined the effects of oral hypoglycemic drugs on blood glucose fluctuations in daily life. Methods: Twenty-nine T2DM patients treated with acarbose were randomized to receive either sitagliptin (14 patients) or mitiglinide (15 patients) together with acarbose for 4 weeks. Patients were then switched to a combination of 10 mg mitiglinide and 0.2 mg voglibose for 4 weeks. All patients wore a continuous glucose monitoring (CGM) device for 5 - 7 days in week 3 of each treatment period. Results: The percentage of blood glucose levels in the hyperglycemic range, blood glucose indices derived from 24-h CGM profiles and the glycemic parameters (HbA1c, glycated albumin and fasting plasma glucose) were significantly improved by adding sitagliptin or mitiglinide to ongoing acarbose therapy. These parameters also tended to improve in the mitiglinide/voglibose combination period. Conclusion: Daily blood glucose fluctuations were significantly improved by adding sitagliptin or mitiglinide to acarbose, and improved after switching to the mitiglinide/voglibose combination. Larger controlled studies are needed to verify the effects of adding sitagliptin or mitiglinide to acarbose on glucose fluctuations. PMID:24866329

Osonoi, Takeshi; Saito, Miyoko; Tamasawa, Atsuko; Ishida, Hidenori; Osonoi, Yusuke

2014-07-01

211

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

Energy Technology Data Exchange (ETDEWEB)

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 (/sup 14/C)-2-deoxyglucose and (/sup 14/C)iodoantipyrine to produce an autoradiogram before and another after extraction into chloroform of the (/sup 14/C)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.

Furlow, T.W. Jr.; Martin, R.M.; Harrison, L.E.

1983-03-01

212

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

1983-01-01

213

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1994-01-01

214

Adjuvant induced glucose uptake by activated T cells is not correlated with increased survival.  

Science.gov (United States)

Authors contributed equally to this manuscript Natural adjuvants, such as bacterial lipopolysaccharide (LPS), activate antigen presenting cells via Toll-like receptors and, indirectly, increase the survival of antigen-activated T cells. The molecular mechanisms leading to increased survival remain poorly defined. Because T cell clonal expansion leads to high energy demands, we hypothesized that increased glucose uptake and/or utilization in adjuvant-activated T cells could be important molecular event(s) that would lead to adjuvant-associated T cell survival advantage. Using a fluorescent analog of 2-deoxyglucose, 2-NBDG, we measured glucose accumulation and rate of uptake in T cells from mice treated with antigen in the absence or presence of LPS. Although adjuvant activated T cells increased the accumulation of 2-NBDG, the rate of uptake was unchanged compared to cells activated with only antigen. Furthermore, glucose transport inhibitors, cytochalasin B or phloretin, decreased the accumulation of glucose in adjuvant-treated T cells, but this decrease did not impair adjuvant-associated survival advantages. Together, these data indicate that increased glucose uptake through glucose transporters is not required for increased survival of activated T cells. PMID:18290315

Sengupta, Sadhak; Vitale, Rebecca J; Chilton, Paula M; Mitchell, Thomas C

2008-01-01

215

Paricalcitol does not improve glucose metabolism in patients with stage 3-4 chronic kidney disease.  

Science.gov (United States)

Patients with chronic kidney disease are often insulin resistant and glucose intolerant--abnormalities that promote cardiovascular disease. Administration of 1,25-dihydroxyvitamin D (calcitriol) has improved glucose metabolism in patients with end-stage renal disease. We conducted a randomized, placebo-controlled clinical trial to test whether paricalcitol, a 1,25-dihydroxyvitamin D analog, changes glucose tolerance in earlier stages of chronic kidney disease. In a crossover design, 22 nondiabetic patients with estimated glomerular filtration rates of stage 3-4 chronic kidney disease and fasting plasma glucose of 100-125 mg/dl were given daily oral paricalcitol for 8 weeks and matching placebo for 8 weeks, separated by an 8-week washout period. The order of interventions was random and blinded to both participants and investigators. Paricalcitol significantly reduced serum concentrations of parathyroid hormone, 1,25-dihydroxyvitamin D, and 25-hydroxyvitamin D while significantly increasing serum concentrations of fibroblast growth factor-23 and 24,25-dihydroxyvitamin D. Paricalcitol, however, had no significant effect on glucose tolerance (the primary outcome measure), insulin sensitivity, beta-cell insulin response, plasma free fatty acid suppression, or urinary F2-isoprostane excretion. Thus, despite substantial effects on vitamin D metabolism, paricalcitol did not improve glucose metabolism in nondiabetic patients with stage 3-4 chronic kidney disease. PMID:22913981

de Boer, Ian H; Sachs, Michael; Hoofnagle, Andrew N; Utzschneider, Kristina M; Kahn, Steven E; Kestenbaum, Bryan; Himmelfarb, Jonathan

2013-02-01

216

Rotanone analogs: method of preparation and use  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides rotenone analogs and methods of making and using them. Labeled with single photon and positron emitting isotopes, the rotenone analogs of the present invention are useful in, for example, clinical imaging applications as tracers to measure cardiac blood flow and detect regions of ischemia.

VanBrocklin, Henry F; O& #x27; Neil, James P; Gibbs, Andrew R; Erathodiyil, Nandanan

2013-10-08

217

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 < 0.05 for both) during intraduodenal glucose infusion. However, the number of duodenal flow events, blood glucose concentration, and plasma 3-[¹?C]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

218

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

219

Thresholds of whole-blood ?-hydroxybutyrate and glucose concentrations measured with an electronic hand-held device to identify ovine hyperketonemia.  

Science.gov (United States)

Metabolic disorders, especially hyperketonemia, are very common in dairy sheep. The whole-blood concentrations of ?-hydroxybutyrate (BHBA) and glucose can be determined by commercially available electronic hand-held devices, which are used in human medicine and for the detection of ketosis in dairy cows. The aim of this study was to evaluate the suitability of the hand-held device Precision Xceed (PX; Abbott Diabetes Care Inc., Abbott Park, IL) to detect hyperketonemia in ewes. An additional objective of this study was to evaluate the agreement between samples obtained by minimal invasive venipuncture of an ear vein and measurements of whole-blood samples from the jugular vein (vena jugularis, v. jug.). Blood samples taken from the v. jug. were collected from 358 ewes on 4 different farms. These samples and a blood drop obtained from an ear vein were analyzed simultaneously on farm with the PX. For method comparison, the samples obtained from the v. jug. were also analyzed by standard methods, which served as the gold standard at the Central Laboratory of the University of Veterinary Medicine Vienna, Austria. The correlation coefficients between the serum BHBA concentration and the concentrations measured with the hand-held meter in the whole blood from an ear vein and the v. jug. were 0.94 and 0.96, respectively. The correlation coefficients of plasma and whole-blood glucose concentration were 0.68 for the v. jug. and 0.47 for the ear vein. The mean glucose concentration was significantly lower in animals classified as hyperketonemic (BHBA ?1.6mmol/L) compared with healthy ewes. Whole-blood concentrations of BHBA and glucose measured with the PX from v. jug. showed a constant negative bias of 0.15mmol/L and 8.4mg/dL, respectively. Hence, a receiver operating characteristic analysis was performed to determine thresholds for the PX to detect hyperketonemia in ewes. This resulted in thresholds for moderate ketosis of BHBA concentrations of 0.7mmol/L in blood from an ear vein and the v. jug. Cutoffs of 1.0mmol/L (ear vein) and 1.1mmol/L (v. jug.) BHBA were determined to detect animals at greater risk to develop severe hyperketonemia. Applying these thresholds, excellent test characteristics, with sensitivities of 1.00 for both samples and specificities of 0.98 for the ear vein and 0.97 for the v. jug. were determined. These results demonstrate that the PX is a useful tool for detection of hyperketonemia in ewes. PMID:24440266

Pichler, M; Damberger, A; Schwendenwein, I; Gasteiner, J; Drillich, M; Iwersen, M

2014-03-01

220

A Tale of Two Compartments: Interstitial Versus Blood Glucose Monitoring  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Self-monitoring of blood glucose was described as one of the most important advancements in diabetes management since the invention of insulin in 1920. Recent advances in glucose sensor technology for measuring interstitial glucose concentrations have challenged the dominance of glucose meters in diabetes management, while raising questions about the relationships between interstitial and blood glucose levels. This article will review the differences between interstitial and blood glucose and...

Cengiz, Eda; Tamborlane, William V.

2009-01-01

 
 
 
 
221

Analogy in CLAM  

Digital Repository Infrastructure Vision for European Research (DRIVER)

CL A M is a proof planner, developed by the Dream group in Edinburgh,that mainly operates for inductive proofs. This paper addresses the questionhow an analogy model that I developed independently of CL A M can beapplied to CL A M and it presents analogy-driven proof plan construction as acontrol strategy of CL A M . This strategy is realized as a derivational analogythat includes the reformulation of proof plans. The analogical replay checkswhether the reformulated justifications of the sour...

Melis, Erica

1999-01-01

222

Analogy Makes Proofs Feasible  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many mathematical proofs are hard to generate forhumans and even harder for automated theoremprovers. Classical techniques of automated theoremproving involve the application of basic rules, of built-in special procedures, or of tactics. Melis (Melis 1993)introduced a new method for analogical reasoning inautomated theorem proving. In this paper we showhow the derivational analogy replay method is relatedand extended to encompass analogy-driven proof planconstruction. The method is evaluated ...

Melis, Erica; Veloso, Manuela

1999-01-01

223

Insulin analogs and cancer  

Directory of Open Access Journals (Sweden)

Full Text Available Today, insulin analogs are used in millions of diabetic patients. Insulin analogs have been developed to achieve more physiological insulin replacement in terms of time course of the effect. Modifications in the amino acid sequence of the insulin molecule change the pharmacokinetics and pharmacodynamics of the analogs in respect to human insulin. However, these changes can also modify the molecular and biological effects of the analogs. The rapid-acting insulin analogs, lispro, aspart and glulisine, have a rapid onset and shorter duration of action. The long-acting insulin analogs glargine and detemir have a protracted duration of action and a relatively smooth serum concentration profile. Insulin and its analogs may function as growth factors and therefore have a theoretical potential to promote tumor proliferation. A major question is whether analogs have an increased mitogenic activity in respect to insulin. These ligands can promote cell proliferation through many mechanisms like the prolonged stimulation of the insulin receptor, stimulation of the IGF-1 receptor (IGF-1R, prevalent activation of the ERK rather than the AKT intracellular post-receptor pathways. Studies on in vitro models indicate that short-acting analogs elicit molecular and biological effects that are similar to those of insulin. In contrast, long-acting analogs behave differently. Although not all data are homogeneous, both glargine and detemir have been found to have a decreased binding to IR but an increased binding to IGF-1R, a prevalent activation of the ERK pathway, and an increased mitogenic effect in respect to insulin. Recent retrospective epidemiological clinical studies have suggested that treatment with long-acting analogs (specifically glargine may increase the relative risk for cancer. Results are controversial and methodologically weak. Therefore prospective clinical studies are needed to evaluate the possible tumor growth-promoting effects of these insulin analogs.

LauraSciacca

2012-02-01

224

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

225

Implantable glucose sensors for diabetes monitoring.  

Science.gov (United States)

The development of glucose sensors for clinical use is driven by the aim of blood glucose normalization in diabetic patients, and the detection of blood glucose impairment in nondiabetic subjects submitted to critical conditions. Currently available devices for continuous glucose monitoring are either minimally invasive or partly implantable, and measure subcutaneous interstitial glucose using glucose-oxidase. The signal generated is calibrated against capillary blood glucose to provide estimated blood glucose values. The three certified glucose sensing systems for clinical use: GlucoWatch(R) biographer, CGMS(R) and GlucoDay(R) use different techniques for glucose recovery: reverse iontophoresis, direct subcutaneous implantation and microdialysis, respectively. These devices show sufficient accuracy to identify trends of blood glucose variations, but provide information either with significant delay (GlucoWatch(R)) or retrospectively after computerized analysis of "Holter-style" glucose recordings (CGMS(R), GlucoDay(R)). Only GlucoDay(R) can provide almost online data. Occasional use for short-term assessment of glucose control or educational purposes in diabetic subjects dominates the present clinical use of these devices. Because of the discrepancies between variations of blood and interstitial glucose levels, treatment adaptations from collected sensor data still need further assessment by capillary blood glucose measurements, while the limited biocompatibility of these systems allows only short-term recordings for a few days at most. Subcutaneous and intravenous, fully implantable, sensor models are currently under development and evaluated in clinical trials. Designed for long-term glucose sensing and permanent clinical use, these glucose sensors show promising early results in view of open-loop or closed-loop insulin delivery based upon a sensor signal. PMID:16754492

Renard

2004-04-01

226

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

227

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

228

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

229

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

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

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

232

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

1986-01-01

233

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

Directory of Open Access Journals (Sweden)

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

Paolo Rossetti

2010-12-01

234

Glucose monitoring by reverse iontophoresis.  

Science.gov (United States)

Glucose can be extracted through intact skin by electro-osmotic flow (a process called 'reverse iontophoresis') upon the application of a low-level electrical current. Recently we have combined iontophoretic extraction with an in situ glucose sensor in a device called the GlucoWatch biographer. Clinical results with this device show close tracking of blood glucose over a range of 2.2 to 22.2 mmol/l for up to 12 h using a single blood glucose value as calibration. The biographer readings lag behind blood glucose values by an average of 18 min. An analysis of data from 92 diabetic subjects in a controlled clinical setting shows a linear relationship (r=0.88) between GlucoWatch biographer readings and blood glucose. The mean absolute relative difference between the two measurements was 15.6% and more than 96% of the data fell in the (A+B) regions of the Clarke error grid. Similar results have been obtained from subjects using the GlucoWatch biographer in an uncontrolled home environment. The automatic, frequent, and non-invasive measurements obtained with the GlucoWatch biographer provide substantially more information about glucose levels than do the current fingerstick methods. This information can be used for improved decisions about all aspects of diabetes management. PMID:11921430

Potts, Russell O; Tamada, Janet A; Tierney, Michael J

2002-01-01

235

Newer insulin analogs: advances in basal insulin replacement.  

Science.gov (United States)

Basal insulin analog therapy is the most common method of introducing insulin replacement therapy for the majority of patients with type 2 diabetes mellitus. Long-acting insulin analogs provide relatively peakless and more physiologic insulin replacement therapy than neutral protaminated Hagedorn insulin. Recently 2 new basal insulin analogs have been developed with superior pharmacokinetic and pharmacodynamics properties; insulin degludec and a pegylated insulin lispro. These agents are generally well tolerated and have been evaluated in both type 1 and type 2 diabetes. In this article we review the results of clinical trials assessing the efficacy, safety and tolerability of these newer longer-acting insulin analogs. In general rates of hypoglycaemia in these trials were low, glucose control was comparable to currently available basal insulin analogs, and rates of nocturnal hypoglycaemia were significantly and substantially lower. While further study will be required, advances in basal insulin replacement may offer important advantages over existing options for starting insulin strategies. PMID:23448197

Zinman, Bernard

2013-03-01

236

Blood Glucose Log  

Science.gov (United States)

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

237

CSF glucose test  

Science.gov (United States)

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

238

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

International Nuclear Information System (INIS)

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

2011-05-01

239

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

240

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

1998-07-01

 
 
 
 
241

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

D Archangelo, Melissa J.

2009-01-01

242

Development of Analogy Experiment Methodologies  

International Nuclear Information System (INIS)

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

2005-01-01

243

Acute metabolic effects of exenatide in patients with type 1 diabetes with and without residual insulin to oral and intravenous glucose challenges.  

Science.gov (United States)

OBJECTIVE Glucagon-like peptide 1 (GLP-1) is an incretin hormone that is released from the gastrointestinal tract. Treatment with GLP-1 analogs has proven to be of clinical use for patients with type 2 diabetes. Patients with type 1 diabetes, particularly those with residual ?-cell function, may also respond to treatment, but the acute metabolic effects of GLP-1 analogs on these patients in reaction to both oral and intravenous glucose challenges are not well understood. RESEARCH DESIGN AND METHODS Seventeen patients with type 1 diabetes, half of whom had residual insulin production, underwent two mixed-meal tolerance tests (MMTTs) and two intravenous glucose tolerance tests (IVGTTs), with and without pretreatment with exenatide. No exogenous bolus insulin was administered for the studies. Glucose excursions, insulin secretion rates (ISRs), and levels of glucagon, endogenous GLP-1, and gastric inhibitory polypeptide were measured after the meal or glucose loads. RESULTS During the MMTT, glucose levels were suppressed with exenatide in patients with or without residual insulin production (P = 0.0003). Exenatide treatment did not change the absolute ISR, but the ISR to glucose levels were increased (P = 0.0078). Gastric emptying was delayed (P = 0.0017), and glucagon was suppressed (P = 0.0015). None of these hormonal or glucose changes were detected during the IVGTT with exenatide administration. CONCLUSIONS Exenatide showed a significant antidiabetogenic effect prior to an oral meal in patients with type 1 diabetes involving glucagon suppression and gastric emptying, while preserving increased insulin secretion. GLP-1 analogs may be useful as an adjunctive treatment in type 1 diabetes. PMID:23939544

Ghazi, Tara; Rink, Linda; Sherr, Jennifer L; Herold, Kevan C

2014-01-01

244

Vancomycin Analogs and Methods Thereof.  

Science.gov (United States)

The present invention generally relates to vancomycin analogs and related methods of synthesis of these analogs. Specifically the invention relates to vancomycin analogs that are directed to vancomycin resistant enterecocci and staphylococci.

J. S. Thorson

2005-01-01

245

HARP: Hierarchical analog readout processor with analog pipelining in CMOS  

International Nuclear Information System (INIS)

Basic functional blocks have been designed and tested: Bipoltest, CSI, SAPE and PIPAD which are a front-end amplifier, a current sampling integrator, an analog pipeline and an analog/digital converter respectively. These functional blocks will eventually be combined in a single chip, and this processor will be the starting point for the HARP architecture. The signal amplifier peaking time for low capacitance detector elements is less than 15 ns. The sampling rate of the pipeline element in the 3 ?m CMOS is measured to be 20 MHz with a dynamic range of ±1.2 pC of input charge which corresponds to 11 bits and the sampling rate in the 1.5 ?m technology is ovver 60 MHz. The ADC operates at 1 MHz sampling rate with 12 mW for 11 bits precision

1990-10-15

246

In vivo measurements of sulcal plaque pH in rats after topical applications of xylitol, sorbitol, glucose, sucrose, and sucrose plus 53 mM sodium fluoride.  

Science.gov (United States)

In two series of experiments, Sprague-Dawley-derived rats were infected orally with cariogenic micro-organisms and fed caries-promoting diets. By means of an antimony electrode, resting pH values were measured in the mesial sulcus of the maxillary left first molar. 100 or 200 microL of the test solutions were applied, and the change in pH (delta pH) was recorded for three min. Test solutions were: (a) 10% sucrose, 10% glucose, 10% sorbitol, or 10% xylitol; (b) 0%, 10%, 20%, or 40% sucrose; (c) 0%, 3%, 7%, or 10% sucrose; and (d) 10% sucrose, 10% sucrose + 53 mmol/L NaF (1000 ppmF-), or 10% sucrose + 53 mmol/L NaCl. Experimental design was a 4 X 4 Latin square (a, b, c) or a cross-over design (d). Solutions of sucrose and glucose gave significantly greater decreases in pH than did sorbitol or xylitol. pH fall was maximal for 10% sucrose and significantly less for 40% sucrose during the three-minute experimental period. For sucrose solutions ranging in concentration from 3 to 10%, pH fall was highest after application of 10% sucrose when plaque was previously rinsed with water, but this pH fall did not differ significantly from that obtained using a 7% sucrose solution. Adding 1000 ppmF- to a 10% sucrose solution caused an increase in pH. Rinsing the teeth to remove saliva resulted in significantly lower resting pH values. The results of these experiments are in agreement with the results of human plaque pH measurements. PMID:3455697

Firestone, A R; Navia, J M

1986-01-01

247

Effect of Delonix Regia Leaf Extract on Glucose Tolerance in Glucose-induced Hyperglycemic Mice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Delonix regia (Fabaceae) leaf is used in folk medicine of Bangladesh for the treatment of diabetes, but so far no scientific study has been done which may support its use in traditional medicine. The present study was carried out to evaluate the possible glucose tolerance efficacy of methanolic extract of Delonix regia leaf using glucose-induced hyperglycemic mice. The extract at different doses was administered one hr prior to glucose administration and blood glucose level was measured after...

Rahman, Mahafuzur; Hasan, Nazmul; Das, Asish Kumar; Hossain, Tozammal; Jahan, Rownak; Khatun, Afsana; Rahmatullah, Mohammed

2011-01-01

248

Fatty acid analogs  

Energy Technology Data Exchange (ETDEWEB)

In one aspect, a radioactively labeled analog of a fatty acid which is capable of being taken up by mammalian tissue and which exhibits an in vivo beta-oxidation rate below that with a corresponding radioactively labeled fatty acid.

Elmaleh, David R. (Newton Center, MA); Livni, Eli (Brookline, MA)

1985-01-01

249

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

250

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

1987-01-01

251

Ionogel-biosensor: novel ionogels based on ionic liquids as a platform to measure enzyme activity of glucose oxdase in real time  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is estimated that there are 170 million diabetics worldwide, and the number continues to rise alarmingly. The management of diabetes is therefore critical to future society, and this is driving demand for point-of-care (POC) glucose biosensors, and they play a central role in the management blood sugar levels in patients with diabetes. Glucose Oxidase (GOx) is a biorecognition enzyme, which recognises the glucose molecule and acts as a catalyst to produce gluconic acid and hydrogen peroxid...

Barry, Caroline; Byrne, Robert; Benito-lopez, Fernando; Diamond, Dermot

2010-01-01

252

Uptake of 13C-glucose by cell suspensions of carrot (Daucus carota) measured by in vivo NMR: Cycling of triose, pentose- and hexose-phosphates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

After a lag phase of 2 days, batch-grown cells of carrot (Daucus carota L.) cv. Flakkese entered the exponential growth phase and started to accumulate sucrose and hexoses. Short-term feeding 13C-glucose in this period resulted in only minor labelling of sucrose or fructose. CO2 production from [1-13C]- and [6-13C]-glucose revealed, that at least 40?f the added glucose passed through the oxidative pentose phosphate pathway (OPPP), up to 40?hrough glycolysis leaving only minor 13C-glucose ...

Krook, J.; Vreugdenhil, D.; Dijkema, C.; Plas, L. H. W.

2000-01-01

253

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

254

A Fuzzy Model for Analogical Problem Solving  

CERN Multimedia

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

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

Evidence for the presence of glucose cycling in pancreatic islets of the ob/ob mouse  

International Nuclear Information System (INIS)

Pancreatic islets from ob/ob mice incubated with 3H2O and 5.5 mM glucose formed 3H-labeled glucose, 74 picoatoms incorporated/islet/h. Sixty-three percent of the 3H was bound to carbon 2 of the glucose. The amount of glucose-6-P dephosphorylated to glucose, determined from this incorporation, was 48 pmol/islet/h. Glucose utilization, measured by the formation of 3H2O from [5-3H]glucose, was 72 pmol/islet/h. The amount of glucose dephosphorylated was then about 40% of that phosphorylated. Thus, glucose-6-P is dephosphorylated to glucose to a significant extent by intact islets in vitro and presumably by the beta cells of the islets. The extent of this glucose cycling, i.e. glucose----glucose-6-P----glucose, may play a role in determining the extent of glucose-induced insulin secretion

1989-06-15

257

Professional Continuous Glucose Monitoring in Clinical Practice 2010  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Professional continuous glucose monitoring (PCGM) is a 3–5 day test done to evaluate diabetes control. The PCGM test uses interstitial glucose measurements done every 5 min with a glucose-oxidase-impregnated membrane. The PCGM test evaluates glucose control retrospectively with the glucose results being unknown to the patient until the results are downloaded after the testing period. The PCGM test allows the practitioner and patient to evaluate the effect of diet, physical activity, medicat...

Blevins, Thomas C.

2010-01-01

258

Glucose kinetics in infants of diabetic mothers  

International Nuclear Information System (INIS)

Glucose kinetic studies were performed to define the glucose turnover rate with 78% enriched D-[U-13C] glucose by the prime constant infusion technique at less than or equal to 6 hours of age in nine infants of diabetic mothers (four insulin-dependent and five chemical diabetic patients) at term. Five normal infants were studied as control subjects. All infants received 0.9% saline intravenously during the study with the tracer. Fasting plasma glucose, insulin, and glucose13/12C ratios were measured during the steady state, and the glucose turnover rate was derived. The average plasma glucose concentration was similar during the steady state in the infants of the diabetic mothers and in the control infants, and the glucose turnover rate was not significantly different among the groups: 2.3 +/- 0.6 mg . kg-1 min-1 in infants of insulin-dependent diabetic patients; 2.4 +/- 0.4 mg . kg-1 min-1 in infants of chemical diabetic patients; and 3.2 +/- 0.3 mg . kg-1 min-1 in the control subjects. Good control of maternal diabetes evidenced by the normal maternal hemoglobin A1c and plasma glucose concentration at delivery and cord plasma glucose concentration resulted in glucose kinetic values in the infants of diabetic mothers that were indistinguishable from those of control subjects. The data further support the importance of good control of the diabetic state in the pregnant woman to minimize or prevent neonatal hypoglycemia

1983-08-01

259

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"-"1"4 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 "1"4CO_2 and lactate production 2.3-fold. With 7 mM glucose, marked decreases in glucose uptake (74%), "1"4CO_2 (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

1986-03-05

260

Analog and digital; Analog to digital  

Energy Technology Data Exchange (ETDEWEB)

The Economic Council has recently announced an economic program targeted at around 2010, pointing out that there will be a drastic transition from the age of modern industrialization to an age of wisdom and putting a stress on the importance of individuality and creativity. The brains consist of the left-brain and the right-brain. The left-brain governs knowledge and logic, the right-brain imagination, creative power, and inspiration. The digital computer has shown up. It is high in capacity and speed, and deals with quantities of data at once, and has wiped out the analog computer. The author does not mean to deny the modern convenience, but fears that people are growing more dependent on the tool, so much so that they are forgetting the use of their brains. For an engineer, the state in which his right-brain is in action is a state in which he is creative and full of inspiration discharging his tasks on the strength of his rich stock of analogous reasoning. Engineering is what one is to acquire only by using one's hands and feet, producing much perspiration. Too much dependence on knowledge and tool will but lead to the depletion of engineering capabilities. The author wants engineers to activate their right-brains and exhibit their creativity. (NEDO)

Inoue, H. [Mazda Motor Corp., Hiroshima (Japan)

1999-11-01

 
 
 
 
261

Mechanism of Insulin-resistant Glucose Transport Activity in the Enlarged Adipose Cell of the Aged, Obese Rat: RELATIVE DEPLETION OF INTRACELLULAR GLUCOSE TRANSPORT SYSTEMS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effects of increasing cell size on glucose transport activity and metabolism and on the concentrations of glucose transport systems in both the plasma and low density microsomal membranes in isolated adipose cells from the aging rat model of obesity have been examined. Glucose transport activity was assessed by measuring l-arabinose transport and the concentration of glucose transport systems estimated by measuring specific d-glucose-inhibitable cytochalasin B-binding. Basal glucose trans...

Hissin, Paul J.; Foley, James E.; Wardzala, Lawrence J.; Karnieli, Eddy; Simpson, Ian A.; Salans, Lester B.; Cushman, Samuel W.

1982-01-01

262

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

Energy Technology Data Exchange (ETDEWEB)

A sensitive and specific radioimmunoassay for (6-D-tryptophan)luteinizing hormone-releasing hormone ((D-Trp/sup 6/)LH-RH) was developed and used for following the rate of liberation of (D-Trp/sup 6/)LH-RH from a long-acting delivery systems based on a microcapsule formulation. Rabbit antibodies were generated against (D-Trp/sup 6/)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-Trp/sup 6/)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-Trp/sup 6/)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 ..mu..g of the peptide, serum (D-Trp/sup 6/)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-Trp/sup 6/)LH-RH was followed. The improved batch of microcapsules of (D-Trp/sup 6/)LH-RH increased serum concentrations of the analog for 30 days or longer after intramuscular injection.

Mason-Garcia, M.; Vigh, S.; Comaru-Schally, A.M.; Redding, T.W.; Somogyvari-Vigh, A.; Horvath, J.; Schally, A.V.

1985-03-01

263

Analog layout synthesis  

CERN Multimedia

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

264

Alternations in salivary glucose during ramadan fasting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the holly month of Ramadan, Muslims fast every day from dawn to sunset. Although the effect of Ramadan fasting on general health has been widely studied, the impact of fasting on oral health and possible changes in salivary biochemicals, such as glucose, has not received much attentiom. The aim of our study was to evaluate the influence of fasting on the level of glucose in the saliva of healthy individuals. Salivary glucose was measured using an enzymatic method based on oxidation of ...

2010-01-01

265

Impact of glucose excursion and mean glucose concentration in oral glucose-tolerance test on oxidative stress among Japanese Americans  

Directory of Open Access Journals (Sweden)

Full Text Available Shuhei Nakanishi, Masayasu Yoneda, Shusaku Maeda Department of Molecular and Internal Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan Aim: To evaluate the impact of glucose excursion (GE and mean glucose concentration (MGC on oxidative stress among persons with or without diabetes. Materials and methods: We examined 775 Japanese Americans who had normal glucose tolerance (NGT, impaired glucose tolerance, or diabetes according to the 75 g oral glucose-tolerance test, using fasting, 1-hour, and 2-hour glucose data. We calculated GE by subtracting the minimum from the maximum glucose level among three points and calculated MGC using these measurements. We investigated the relationship between GE or MGC and urinary isoprostane as a marker of oxidative stress. Results: According to tertiles of GE or MGC, GE was associated with isoprostane levels among subjects with NGT as well as those with diabetes (P=0.004 and 0.033 for trend, respectively. However, MGC was associated with isoprostane only among NGT subjects (P=0.001 for trend. Association between GE and isoprostane was significant when adjustment was made for age, sex, smoking status, body mass index, C-reactive protein, glucose tolerance status, and homeostatic model assessment (P=0.029, but the association with MGC was not significant. Conclusion: Our results suggest the possibility that GE might result in oxidative stress, and the relationship is stronger than that for MGC. Keywords: glucose excursion, glucose-tolerance test, oxidative stress

Nakanishi S

2013-11-01

266

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

International Nuclear Information System (INIS)

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

1982-01-01

267

Prognostic significance of the Complex "Visceral Adiposity Index" vs. simple anthropometric measures: Tehran lipid and glucose study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Visceral adiposity index (VAI has recently been suggested to be used as a surrogate of visceral adiposity. We examined if VAI could improve predictive performances for CVD of the Framingham's general CVD algorithm (a multivariate model incorporating established CVD risk factors. We compared the predictive abilities of the VAI with those of simple anthropometric measures i.e. BMI, waist-to-height ratio (WHtR or waist-to-hip ratio (WHpR. Design and methods In a nine-year population-based follow-up, 6 407 (2 778 men participants, free of CVD at baseline, aged ? 30 years were eligible for the current analysis. The risk of CVD was estimated by incorporating VAI, BMI, WHpR, and WHtR, one at a time, into multivariate accelerated failure time models. Results We documented 534 CVD events with the annual incidence rate (95%CIs being 7.3 (6.4-8.3 among women and 13.0 (11.7-14.6 among men. Risk of future CVD increased with increasing levels of VAI among both men and women. VAI was associated with multivariate-adjusted increased risk of incident CVD among women. However, the magnitude of risk conferred by VAI was not significantly higher than those conferred by BMI, WHpR, or WHtR. Among men, after adjustment for established CVD risk factors, VAI was no longer associated with increased risk of CVD. VAI failed to add to the predictive ability of the Framingham general CVD algorithm. Conclusions Using VAI instead of simple anthropometric measures may lead to loss of much information needed for predicting incident CVD.

Mohammadreza Bozorgmanesh

2012-03-01

268

Fusion-Fission Analogy.  

Science.gov (United States)

The analogy of plasma ignition of fusion devices to criticality in fission systems is shown. The four-factor formula is presented and special emphasis is given to the energy utilization factor, which now dominates fusion research. Instead of keeping books...

J. R. McNally

1977-01-01

269

How Analogy Drives Physics  

International Nuclear Information System (INIS)

Many new ideas in theoretical physics come from analogies to older ideas in physics. For instance, the abstract notion of 'isospin' (or isotopic spin) originated in the prior concept of 'spin' (quantized angular momentum); likewise, the concept of 'phonon' (quantum of sound, or quantized collective excitation of a crystal) was based on the prior concept of 'photon' (quantum of light, or quantized element of the electromagnetic field). But these two examples, far from being exceptions, in fact represent the bread and butter of inventive thinking in physics. In a nutshell, intraphysics analogy-making -- borrowing by analogy with something already known in another area of physics -- is central to the progress of physics. The aim of this talk is to reveal the pervasiveness -- indeed, the indispensability -- of this kind of semi-irrational, wholly intuitive type of thinking (as opposed to more deductive mathematical inference) in the mental activity known as 'doing physics'. Speculations as to why wild analogical leaps are so crucial to the act of discovery in physics (as opposed to other disciplines) will be offered.

2004-05-05

270

Quantum Analog Computing  

Science.gov (United States)

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

Zak, M.

1998-01-01

271

Analog signal isolation techniques  

Energy Technology Data Exchange (ETDEWEB)

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.

Beadle, E.R.

1992-01-01

272

Analog signal isolation techniques  

Energy Technology Data Exchange (ETDEWEB)

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.

Beadle, E.R.

1992-12-31

273

Thermomagnetic Analog Recording.  

Science.gov (United States)

The thermomagnetic recording of an analog signal on a CrO2 magnetic tape using a conventional magnetic head and a laser beam as a heating source, is discussed. It was concluded from experimental results that the method can be used for fairly high density ...

T. Nomura K. Yokoyama

1973-01-01

274

A multistep algorithm for processing and calibration of microdialysis continuous glucose monitoring data  

DEFF Research Database (Denmark)

The deviation of continuous subcutaneous glucose monitoring (CGM) data from reference blood glucose measurements is substantial, and adequate signal processing is required to reduce the discrepancy between subcutaneous glucose and blood glucose values. The purpose of this study was to develop a multistep algorithm for the processing and calibration of continuous subcutaneous glucose monitoring data with high accuracy and short delay. Algorithm

Mahmoudi, Zeinab; Dencker Johansen, Mette

2013-01-01

275

[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

276

Alternations in salivary glucose during ramadan fasting  

Directory of Open Access Journals (Sweden)

Full Text Available During the holly month of Ramadan, Muslims fast every day from dawn to sunset. Although the effect of Ramadan fasting on general health has been widely studied, the impact of fasting on oral health and possible changes in salivary biochemicals, such as glucose, has not received much attentiom. The aim of our study was to evaluate the influence of fasting on the level of glucose in the saliva of healthy individuals. Salivary glucose was measured using an enzymatic method based on oxidation of glucose by glucoseoxidase followed by determination of resulting H2O2 in the presence of peroxidase. A reduction in mean concentration of glucose was observed in the saliva of all fasting subjects as compared to the control group. It was concluded that reduction in salivary glucose is mostly due to reduced food intake and may be beneficial to dental health.

Ali Erfani

2010-07-01

277

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

1989-01-01

278

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: ...

279

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 & ...

280

2-deoxy-glucose-6-phosphate utilization in the study of glucose-6-phosphate dehydrogenase mosaicism.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electrophoretic difference between normal glucose-6-phosphate dehydrogenase (G6PD) and two common variants (G6PD A and G6PD A-) has made the G6PD enzyme system very useful for genetic studies and for investigation on the clonal origin of tumors. This approach has not been possible for another common variant, G6PD mediterranean, which has a normal electrophoretic pattern. The different utilization of 2-deoxy-glucose-6-phosphate (2dG6P), an analog of the normal substrate, by the normal enzy...

Ferraris, A. M.; Giuntini, P.; Galiano, S.; Gaetani, G. F.

1981-01-01

 
 
 
 
281

Entanglement and thermodynamical analogies  

CERN Document Server

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 entanglement i.e. the amount of singlet pairs needed for local preparation of a state corresponds to internal energy while the free entanglement defined as the number of pairs which can be recovered from the state (distillable entanglement) is the counterpart of free energy. In particular, it leads us to the question about ``temperature'' of entanglement. We also propose a scheme of the search of representative state for given entanglement which can be viewed as an analogue of the Jaynes maximum entropy principle.

Horodecki, P; Horodecki, M; Horodecki, Pawel; Horodecki, Ryszard; Horodecki, Michal

1998-01-01

282

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Carbohydrate Counting Make Your Carbs Count Glycemic Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type ... Checking Your Blood Glucose A1C and eAG Hypoglycemia (Low blood glucose) Hyperglycemia (High blood glucose) Dawn Phenomenon ...

283

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... urination Increased thirst Part of managing your diabetes is checking your blood glucose often. Ask your doctor how often ... your blood glucose level by exercising. However, if your blood glucose is above 240 mg/dl, check your urine for ...

284

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

1990-01-01

285

Analog storage integrated circuit  

Energy Technology Data Exchange (ETDEWEB)

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

Walker, J. T. (Palo Alto, CA); Larsen, R. S. (Menlo Park, CA); Shapiro, S. L. (Palo Alto, CA)

1989-01-01

286

Cell based metabolic barriers to glucose diffusion: macrophages and continuous glucose monitoring.  

Science.gov (United States)

It is assumed that MQ are central to glucose sensor bio-fouling and therefore have a major negative impact on continuous glucose monitoring (CGM) performance in vivo. However to our knowledge there is no data in the literature to directly support or refute this assumption. Since glucose and oxygen (O2) are key to glucose sensor function in vivo, understanding and controlling glucose and O2 metabolic activity of MQ is likely key to successful glucose sensor performance. We hypothesized that the accumulation of MQ at the glucose sensor-tissue interface will act as "Cell Based Metabolic Barriers" (CBMB) to glucose diffusing from the interstitial tissue compartment to the implanted glucose sensor and as such creating an artificially low sensor output, thereby compromising sensor function and CGM. Our studies demonstrated that 1) direct injections of MQ at in vivo sensor implantation sites dramatically decreased sensor output (measured in nA), 2) addition of MQ to glucose sensors in vitro resulted in a rapid and dramatic fall in sensor output and 3) lymphocytes did not affect sensor function in vitro or in vivo. These data support our hypothesis that MQ can act as metabolic barriers to glucose and O2 diffusion in vivo and in vitro. PMID:24461328

Klueh, Ulrike; Frailey, Jackman T; Qiao, Yi; Antar, Omar; Kreutzer, Donald L

2014-03-01

287

Electronic Computers and Analog Devices.  

Science.gov (United States)

The handbook presents a classification of electronic and analog computers and analog devices, including descriptions, basic technical features and fields of application of domestically-manufactured universal digital computers, digital control devices, dig...

V. I. Grubov V. S. Kirdan

1971-01-01

288

Lag time changes between capillary blood glucose and in-vivo interstitial glucose levels by HATR-FTIR spectroscopy  

Science.gov (United States)

Method of the lag/latency time (LT) measurement, calculation and interpretation can be simultaneously applied to study in vivo glucose diffusion from the capillary to the skin tissue, to calibrate spectroscopically measured glucose levels during real-time glucose monitoring of dynamic processes in the skin tissue and to study glucose optical properties in the living skin tissue. Based on previous reports on determining interstitial glucose levels and their LT's by HATR-FTIR spectroscopy, here the LT was calculated for each glucose absorbance level at about 1030-41, 1080, 1118 and 1153 cm-1 during oral glucose tolerance test (OGTT) with different doses (5g, 20g, 75g). The LT showed dose-dependency and described intra-/inter-subject changes of skin glucose dynamics in healthy and diabetes subjects. The time required for glucose to diffuse from the capillary to the skin tissue was shorter in a diabetes subject, than in a healthy subject, independently on intaken dose of glucose. Nevertheless, in both subjects the LT changes ranged within 0?50 minutes. Measurement of the LT demonstrated a potential to provide insight to healthy and diabetic glucose dynamics between the blood and interstitial fluid compartments in the upper layer of the skin tissue. Also, the LT might be regarded as a method to calibrate dynamic measurements of glucose in vivo by this spectroscopy method and to characterize living skin tissue glucose optical properties.

Eikje, Natalja Skrebova

2011-02-01

289

Liver fat content, evaluated through semi-quantitative ultrasound measurement, is associated with impaired glucose profiles: a community-based study in Chinese.  

Science.gov (United States)

Nonalcoholic fatty liver disease (NAFLD) is closely associated with type 2 diabetes mellitus. We investigated whether the deposition of fat in the liver is associated with glycemic abnormalities and evaluated the contribution of the liver fat content (LFC) to the impaired glucose regulation. We conducted a community-based study among 2836 residents (1018 males and 1818 females) without prior known diabetes mellitus from the Changfeng Study who were at least 45 years old. A standard interview, anthropometrics and laboratory parameters were performed for each participant. The standardised ultrasound hepatic-renal echo-intensity and hepatic echo-intensity attenuation rate were used to assess the LFC. The cohort was stratified according to the quintiles for LFC. Two-hour glucose and fasting blood glucose increased across the LFC quintiles after adjustment for age and gender. LFC increased continuously among glucose categories after adjustment for age and gender (NGT: 7.7±0.3%, IFG: 10.0±0.8%, IGT: 11.8±0.5%, IFG+IGT: 11.7±0.9%, new- DM: 12.4±0.6%, P<0.001). By logistic regression analysis, 1% LFC increment independently predicted prediabetes and diabetes (OR 1.032, 1.019-1.045, P<0.001; 1.021, 1.005-1.037, P?=?0.012, respectively) after adjustment for all potential confounders. Furthermore, participants with LFC higher than 10% had higher odds ratios of impaired glucose regulation as compared with those with LFC below 10% in fully adjusted logistic models. These results suggest that the LFC is strongly associated with impaired glucose regulation in the Chinese population, and that an even slightly elevated LFC is associated with increased glucose dysregulation. PMID:23843938

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

2013-01-01

290

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

291

FASTBUS 16-channel 8-bit analog-to-digital converter  

International Nuclear Information System (INIS)

A FASTBUS 16-channel 8-bit analog-to-digital converter is described. The module is made on the basis of an ultrafast integrated analog-to-digital converter (flash ADC K1107PV3). The range of the measured analog signals is ±2 V. An analog signal is converted to the digital code lineraly. Information from the ADC is read out via a FASTBUS dataway from two channels simultaneously during ? 40 ns. The 16-channel ADC is used in the system for measuring the characteristics from the scintillation hodoscopes of the spectrometer SPHERE

1988-01-01

292

Maternal glucose level and body mass index measured at gestational diabetes mellitus screening and the risk of macrosomia: results from a perinatal cohort study  

Science.gov (United States)

Objective To examine the impact of maternal blood glucose (BG) level and body mass index (BMI) measured at gestational diabetes mellitus (GDM) screening on the risk of macrosomia. Design A perinatal cohort of women were followed up from receiving perinatal healthcare to giving birth. Setting Beichen District, Tianjin, China between June 2011 and October 2012. Participants 1951 women aged 19–42?years with valid values of BMI and BG level at GDM screening (24–28?weeks gestation), singleton birth and birth weight (BW)>2500?g. Main outcomes and measures Primary outcome was macrosomia (BW>4000?g). BG level and BMI were measured at GDM screening. Results 191 (9.7%) newborns were macrosomia. The ORs (95% CIs) of macrosomia from multiple logistic regression were 1.14 (1.10 to 1.19, p<0.0001) for BMI and 1.11 (1.01 to 1.23, p=0.03) for BG. When BMI and BG levels (continuous) were modelled simultaneously, the OR for BMI was similar, but significantly attenuated for BG. Areas of receiver operating characteristics (ROC) were 0.6530 (0.6258 to 0.6803) for BMI and 0.5548 (0.5248 to 0.5848) for BG (?2=26.17, p<0.0001). BG (mmol/L, <6.7, 6.7–7.8 or ?7.8) and BMI in quintiles (Q1–Q5) were evaluated with BG <6.7 and Q2 BMI as the reference group. The ORs of macrosomia were not statistically different for mothers in Q1 or Q2 of BMI regardless of the BG levels; the ORs for ?Q3 of BMI were elevated significantly with the highest OR observed in Q5 of BMI and BG levels ?7.8 (6.93 (2.61 to 18.43), p<0.0001). Conclusions High BMI measured at GDM screening was the most important determinant for risk of macrosomia. These findings suggest that GDM screening may be a critical gestational time point to initiate maternal weight control oriented intervention strategy to lower the risk.

Liu, Jian; Leng, Junhong; Tang, Chen; Liu, Gongshu; Hay, John; Wang, Jing; Wen, Shiwu; Li, Zhenling; She, Ye

2014-01-01

293

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

Directory of Open Access Journals (Sweden)

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

Lincoln Saito Millan

2012-12-01

294

Quantification of the Variability of Continuous Glucose Monitoring Data  

Directory of Open Access Journals (Sweden)

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

Edward Aboufadel

2011-02-01

295

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

International Nuclear Information System (INIS)

A double isotope method was used in patients with progressive malignancy and in control patients to measure: glucose turnover, conversion rate of carbon skeleton of glycerol into glucose, and the interorgan cycling of glucose carbons (Cori-cycle plus alanine-glucose cycle). [U-_1_4C]glycerol and [6-_3H]glucose were given intravenously as a single dose injection. The time course of the specific radioactivities of [6-_3H] and [U-_1_4C]glucose was followed in blood. The pool size and the turnover rate of glucose were increased in the cancer group as compared with the control patients. The net recycling of glucose carbons was not increased in the cancer group, despite the increased turnover of glucose. The alterations in the metabolism of glucose did not correlate with the plasma levels of insulin or thyroid hormones (T4, T3, rT3) neither in the entire cancer group nor in those cancer patients who were repeatedly investigated at different intervals of time. The turnover rate of glucose in the cancer patients correlated inversely to their body weight index. The gluconeogenesis rate, given as the fractional conversion rate of the injected radioactive dose of [_1_4C]glycerol, or as mol glucose . kg body weight-1 . day-1, was increased in the cancer group, but still contributed only 3% of the glucose turnover rate in both cancer and control patients. We conclude that an increased gluconeogenesis from glycerol is not significant in terms of energy expenditure in patients with progressive malignancy, as has previously been concluded for the gluconeogenesis from alanine. It seems that increased turnover of glucose may contribute to inappropriately high energy expenditure in cancer patients

1982-09-15

296

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 responders and nonresponders (p = 0.32). Conclusions: Early changes in MRGlu predict response to temozolomide, but not temozolomide plus radiotherapy

2006-10-01

297

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.

298

A new removable implant analog.  

Science.gov (United States)

A new implant analog system that improves the efficiency of the implant restoration's fabrication process is described. This 2-piece analog contains an outer plastic sleeve that is retained within the stone cast. The inner portion, a metal analog, can be easily removed and replaced within the plastic sleeve. Because the metal analog is removable, the time-consuming process of screwing and unscrewing the prosthesis- or abutment-retaining screws during laboratory procedures can be minimized. The prosthesis can remain secured to the analog during waxing, metal finishing, and porcelain buildup, yet is easily removed from the cast for inspection. PMID:12964689

Rasetto, Flavio H; Driscoll, Carl F

2003-06-01

299

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

300

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

DEFF Research Database (Denmark)

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

Christensen, Mikkel B; Holst, Jens Juul

2014-01-01

 
 
 
 
301

Glucose-dependent insulinotropic polypeptide : blood glucose stabilizing effects in patients with type 2 diabetes  

DEFF Research Database (Denmark)

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

Christensen, Mikkel B; Holst, Jens Juul

2014-01-01

302

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

Science.gov (United States)

Context: Patients with type 2 diabetes mellitus (T2DM) have clinically relevant disturbances in the effects of the hormone glucose-dependent insulinotropic polypeptide (GIP). Objective: We aimed to evaluate the importance of the prevailing plasma glucose levels for the effect of GIP on responses of glucagon and insulin and glucose disposal in patients with T2DM. Design and Setting: We performed a single center, placebo-controlled, cross-over, experimental study. Patients: We studied twelve patients with T2DM (age: 62 ± 1 years [mean ± SEM], body mass index: 29 ± 1 kg/m(2); glycosylated hemoglobin A1c: 6.5 ± 0.1% [48 ± 2 mmol/mol]). Intervention: We infused physiological amounts of GIP (2 pmol × kg(-1) × min(-1)) or saline. Main Outcome Measures: We measured plasma concentrations of glucagon, glucose, insulin, C-peptide, intact GIP, and amounts of glucose needed to maintain glucose clamps. Results: During fasting glycemia (plasma glucose ?8 mmol/L), GIP elicited significant increments in both insulin and glucagon levels, resulting in neutral effects on plasma glucose. During insulin-induced hypoglycemia (plasma glucose ?3 mmol/L), GIP elicited a minor early-phase insulin response and increased glucagon levels during the initial 30 minutes, resulting in less glucose needed to be infused to maintain the clamp (29 ± 8 vs 49 ± 12 mg × kg(-1), P < .03). During hyperglycemia (1.5 × fasting plasma glucose ?12 mmol/L), GIP augmented insulin secretion throughout the clamp, with slightly less glucagon suppression compared with saline, resulting in more glucose needed to maintain the clamp during GIP infusions (265 ± 21 vs 213 ± 13 mg × kg(-1), P < .001). Conclusions: In patients with T2DM, GIP counteracts insulin-induced hypoglycemia, most likely through a predominant glucagonotropic effect. In contrast, during hyperglycemia, GIP increases glucose disposal through a predominant effect on insulin release. PMID:24423311

Christensen, Mikkel B; Calanna, Salvatore; Holst, Jens J; Vilsbøll, Tina; Knop, Filip K

2014-03-01

303

Analog-microchip for ALICE TRD  

International Nuclear Information System (INIS)

For the ALICE Transition Radiation Detector (TRD) a first version of an analog chip was implemented and tested. It consists of a number of analog channels, and is the first block of the front end electronics receiving the signals from the detector pads. The current signals of the detector pads are first amplified by a charge-sensitive preamplifier. It is followed by a pole-zero cancellation circuit and a second order shaper-filter ensuring a shaped output pulse with about 125 ns FWHM. The last functional element of the analog channel chain is the output amplifier. It delivers an output signal according to the ADC requirements concerning driving capability and output levels. The overall gain of the analog channel is 5.2 mV/fC and the shaping type is CR-(RC)2. The output amplifier acts an external 8-bit 2 V range fast ADC (National type NS 08351). In the first version of the TRD analog chip 21-analog channels, basically the same, were provided. The only difference refers to the value of input pad resistance. There are 8 channels with 0 ohms, 8 channels with 50 ohms, 2 channels with 200 ohms and 2 channels with 500 ohms, to estimate the influence of the pad input resistance to overall noise. One additional channel with 50 ohms input resistance (probe channel) allows monitoring the signal in each main parts of the analog channel, not only to the output. The first results obtained from the measurements of the analog channels of the chip are very similar with those from simulation. The mains results are given in a table containing the Gain, Shaping Type, Input dynamic range, Equivalent input noise, Output pulse level, Integral nonlinearity and Max. power consumption/ch. The signals in the probe channel, corresponding to preamplifier, pole- zero circuit, shaper and output amplifier are shown. The first version of the analog chip for ALICE TRD was built and tested. The results fulfil the initial requirements. At present the chips of this first versions are used in the multichip module card (MMC), containing ADCs and a digital chip, which is the whole configuration of the front end electronics. Very soon the 2nd version of the analog chip will be submitted. For this the shaping type is CR-(RC)4, the estimated equivalent of 700 e, the input dynamic range of 165 fC, the gain of about 6.1 mV/fC, and the output of differential type. (authors)

2001-01-01

304

Regulation of the glucose phosphotransferase system in Brochothrix thermosphacta by membrane energization.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Uptake of 2-deoxyglucose, alpha-methylglucopyranoside, and glucose into intact cells of Brochothrix thermosphacta (formerly Microbacterium thermosphactum, ATCC 11509) was stimulated by KCN or CCCP. The glucose analogs were recovered almost totally as the sugar phosphates. Membrane vesicles were isolated from protoplasts and shown to be right side out by freeze fracturing and by using ATPase as a marker for the cytoplasmic membrane surface. Uptake of glucose into vesicles was dependent on the ...

1985-01-01

305

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1984-01-01

306

Laboratory analog experiment  

International Nuclear Information System (INIS)

The status of the Laboratory Analog Program being conducted for the Nuclear Regulatory Commission at Argonne National Laboratory is reviewed. This is an integrated experiment designed to determine how well the behavior of a breached basalt repository is understood. The general conclusion is that Sentinel Gap basalt reacts readily at low temperature with water to produce an assemblage including clay minerals throughout the range of experimentation. These minerals may be useful as adsorbers for material emplanted in the basalt. It is recommended that sorption capabilities be investigated with specific ions

1982-08-01

307

An intracellular glucose biosensor based on nanoflake ZnO  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, an improved potentiometric intracellular glucose biosensor was fabricated with immobilization of glucose oxidase on a ZnO nanoporous material. The ZnO nanoporous material with a wall thickness around 200 nm was grown on the tip of a borosilicate glass capillary and used as a selective intracellular glucose sensor for the measurement of glucose concentrations in human adipocytes and frog oocytes. The results showed a fast response within 4 s and a linear glucosedependent electro...

Fulati, Alimujiang; Usman Ali, Syed M.; Asif, Muhammad H.; Hassan Alvi, Naveed Ul; Willander, Magnus; Bra?nnmark, Cecilia; Stra?lfors, Peter; Bo?rjesson, Sara I.; Elinder, Fredrik; Danielsson, Bengt

2010-01-01

308

Demographic and metabolic characteristics of individuals with progressive glucose tolerance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We evaluated changes in glucose tolerance of 17 progressors and 62 non-progressors for 9 years to improve our understanding of the pathogenesis of type 2 diabetes mellitus. Changes in anthropometric measurements and responses to an oral glucose tolerance test (OGTT) were analyzed. We identified 14 pairs of individuals, one from each group, who were initially normal glucose tolerant and were matched for gender, age, weight, and girth. We compared initial plasma glucose and insulin curves (from...

Mendes, A. L.; Santos, M. L.; Padovani, C. R.; Pimenta, W. P.

2009-01-01

309

Comb Filters with Analog Shift Registers BCCD  

Directory of Open Access Journals (Sweden)

Full Text Available This contribution deals with the concept and circumferential structure of comb filter for video signal processing. The comb filter was implemented by means of an analog shift register CCD (BCCD. The main conclusions, including the measured frequency response characteristic and time responses of the necessary control signals, are presented. This problem has been investigated as part of the GACR project.

V. Novotny

1995-09-01

310

Analog Scales of Affective and Continuance Commitment.  

Science.gov (United States)

The Army has assembled an archive of survey data for use in studies and analyses on practical issues pertinent to the career decisions of officers. This effort applied the analog approach for empirically deriving and validating measures in order to expand...

T. R. Tremble S. C. Payne R. C. Bullis

1998-01-01

311

Modeling the glucose sensor error.  

Science.gov (United States)

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

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

2014-03-01

312

Development of a Robust Optical Glucose Sensor  

Science.gov (United States)

The long term objective of this research was the development of a noninvasive, optically-based, polarimetric sensor to monitor in vivo glucose concentrations. The goal of diabetes therapy is to approximate the 24-hour blood glucose profile of a normal individual. There have been major advances in the development of reliable, versatile, and accurate pumps for the delivery of insulin to diabetic patients and in the development of control algorithms for closed-loop insulin delivery, however, there remain major obstacles to the development of clinically useful, continuous glucose sensors. The development of an accurate noninvasive glucose sensor would have significant application in the diagnosis and management of diabetes mellitis both in conjunction with, and independent of, the glucose pump controller applications. The linear polarization vector of light routes when it interacts with an optically active material such as glucose. The amount of rotation of polarization is directly proportional to the glucose concentration and to the path length. The ability to quantitate blood glucose levels for the limited available path length in our primary sensing site, namely, the anterior chamber of the eye, therefore depends on the signal-to-noise ratio of the polarization detector. Our primary research focused on the development and testing of a prototype optical polarimetry system using D + glucose solution in a test cell, as well as using an enucleated human eye to assess the sensitivity of the system to measure physiologic glucose levels for the approximate one centimeter path length present in the anterior chamber of the eye. Our research has led to the development of a true phase technique in which helium neon laser light was coupled through a rotating linear polarizer along with two stationary linear polarizers and two detectors to produce reference and signal outputs whose amplitudes varied sinusoidally and whose phase was proportional to the rotation of light caused by the glucose solution.

Cote, Gerard Laurence

1990-01-01

313

Construction of a Glucose Biosensor by Immobilizing Glucose Oxidase within a Poly(o-phenylenediamine) Covered Screen-printed Electrode  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The glucose biosensors were prepared by the electropolymerization of the non-conductive polymer, Poly(o-phenylenediamine), onto a planar screen-printed electrode. A fabrication procedure was performed to decrease the waste of expensive enzyme. The amperometric glucose response was measured by the potensiostating of the prepared glucose biosensors at a potential of 0.3 V with ferrocene as mediator. Results show that the obtained biosensors have a linear range up to 25 mM glucose, fast response...

Miao Yuqing; Chen Jianrong; Wu Xiaohua

2006-01-01

314

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 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

2003-08-17

315

Planning a site investigation using analogous groups  

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-09-01

316

Planning a site investigation using analogous groups  

International Nuclear Information System (INIS)

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

1993-10-24

317

New Insights into Cytosolic Glucose Levels during Differentiation of 3T3-L1 Fibroblasts into Adipocytes*  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cytosolic glucose concentration reflects the balance between glucose entry across the plasma membrane and cytosolic glucose utilization. In adipocytes, glucose utilization is considered very rapid, meaning that every glucose molecule entering the cytoplasm is quickly phosphorylated. Thus, the cytosolic free glucose concentration is considered to be negligible; however, it was never measured directly. In the present study, we monitored cytosolic glucose dynamics in 3T3-L1 fibroblasts and adipo...

Kovacic, Petra Brina; Chowdhury, Helena H.; Velebit, Jelena; Kreft, Marko; Jensen, Jørgen; Zorec, Robert

2011-01-01

318

An Hg-sensitive channel mediates the diffusional component of glucose transport in olive cells.  

Science.gov (United States)

In several organisms solute transport is mediated by the simultaneous operation of saturable and non-saturable (diffusion-like) uptake, but often the nature of the diffusive component remains elusive. The present work investigates the nature of the diffusive glucose transport in Olea europaea cell cultures. In this system, glucose uptake is mediated by a glucose-repressible, H(+) -dependent active saturable transport system that is superimposed on a diffusional component. The latter represents the major mode of uptake when high external glucose concentrations are provided. In glucose-sufficient cells, initial velocities of D- and L-[U-(14)C]glucose uptake were equal and obeyed linear concentration dependence up to 100 mM sugar. In sugar starved cells, where glucose transport is mediated by the saturable system, countertransport of the sugar pairs 3-O-methyl-D-glucose/D-[U-(14)C]glucose and 3-O-methyl-D-glucose/3-O-methyl-D-[U-(14)C]glucose was demonstrated. This countertransport was completely absent in glucose-sufficient cells, indicating that linear glucose uptake is not mediated by a typical sugar permease. The endocytic inhibitors wortmannin-A and NH(4)Cl inhibited neither the linear component of D- and L-glucose uptake nor the absorption of the nonmetabolizable glucose analog 3-O-methyl-D-[U-(14)C]glucose, thus excluding the involvement of endocytic mediated glucose uptake. Furthermore, the formation of endocytic vesicles assessed with the marker FM1-43 proceeded at a very slow rate. Activation energies for glucose transport in glucose sufficient cells and plasma membrane vesicles were 7 and 4 kcal mol(-1), respectively, lower than the value estimated for diffusion of glucose through the lipid bilayer of phosphatidylethanolamine liposomes (12 kcal mol(-1)). Mercury chloride inhibited both the linear component of sugar uptake in sugar sufficient cells and plasma membrane vesicles, and the incorporation of the fluorescent glucose analog 2-NBDG, suggesting protein-mediated transport. Diffusive uptake of glucose was inhibited by a drop in cytosolic pH and stimulated by the protein kinase inhibitor staurosporine. The data demonstrate that the low-affinity, high-capacity, diffusional component of glucose uptake occurs through a channel-like structure whose transport capacity may be regulated by intracellular protonation and phosphorylation/dephosphorylation. PMID:17706590

Conde, Carlos; Silva, Paulo; Agasse, Alice; Tavares, Rui M; Delrot, Serge; Gerós, Hernâni

2007-11-01

319

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

320

Appetite Sensations, Appetite Signaling Proteins, and Glucose in Obese Adolescents with Subclinical Binge Eating Disorder  

Science.gov (United States)

Objective. This study aimed to investigate potential differences in appetite sensations, ghrelin, peptide YY, and glucose and their relationship with energy and macronutrient intake in obese adolescents with subclinical binge eating disorder. Methods. Fifteen obese adolescents (six and nine individuals with and without subclinical binge eating disorder, resp.) qualified for this study. Visual analog scales and Three-Factor Eating Questionnaires were used to assess eating behaviours. Circulating ghrelin, peptide YY, and glucose were measured after fasting and at multiple time points postprandially following a standardized breakfast meal. Energy and macronutrient intake were measured with an ad libitum lunch buffet. Results. Emotional eating scores were significantly higher in obese adolescents with subclinical binge eating disorder. Hunger levels rose and satiety levels fell significantly over the course of the monitoring period but there was no difference between the two groups. Obese adolescents with subclinical binge eating disorder did not have significantly different levels of appetite signaling proteins or glucose. Obese adolescents with subclinical binge eating disorder had a nonsignificantly higher energy and macronutrient intake. Conclusions. A significant difference between the two groups in terms of their emotional eating scores highlights the important role that psychological factors play in relation to eating behaviours.

Adamo, Kristi B.; Wilson, Shanna L.; Ferraro, Zachary M.; Hadjiyannakis, Stasia; Doucet, Eric; Goldfield, Gary S.

2014-01-01

 
 
 
 
321

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

322

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

323

Brain Glucose Metabolism Controls Hepatic Glucose and Lipid Production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Brain glucose-sensing mechanisms are implicated in the regulation of feeding behavior and hypoglycemic-induced hormonal counter-regulation. This commentary discusses recent findings indicating that the brain senses glucose to regulate both hepatic glucose and lipid production.

Lam, Tony K. T.

2007-01-01

324

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

325

Continuous glucose monitoring  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Pandit, Kaushik

2012-01-01

326

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

327

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

Directory of Open Access Journals (Sweden)

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

Giray Bozkaya

2010-01-01

328

Comparison of {sup 18}F- and {sup 11}C-labeled aryloxyanilide analogs to measure translocator protein in human brain using positron emission tomography  

Energy Technology Data Exchange (ETDEWEB)

Translocator protein (TSPO) is a promising biomarker for neuroinflammation. We developed two new PET ligands, {sup 18}F-PBR06 and {sup 11}C-PBR28, to image TSPOs. Although our prior studies suggest that either of the two ligands could be used to quantify TSPOs in human brain, the studies were done in different sets of subjects. In this study, we directly compared {sup 18}F-PBR06 and {sup 11}C-PBR28 in eight human subjects to determine (1) whether either ligand provides more precise measurements of TSPOs and (2) whether the higher in vitro affinity of PBR06 compared to PBR28 led to higher in vivo binding of {sup 18}F-PBR06 compared to {sup 11}C-PBR28. In vivo binding was calculated as total distribution volume (V{sub T}), using an unconstrained two-tissue compartment model. V{sub T} was corrected for plasma free fraction (f{sub P}) to measure ligand binding based on free ligand concentration in brain. Both ligands measured V{sub T} with similar precision, as evidenced by similarly good identifiability. However, V{sub T} for both radioligands increased with increasing lengths of data acquisition, consistent with the accumulation of radiometabolites in brain. Despite its higher lipophilicity and higher in vitro affinity, V{sub T}/f{sub P} of {sup 18}F-PBR06 was similar to that of {sup 11}C-PBR28. Both {sup 18}F-PBR06 and {sup 11}C-PBR28 are similar in terms of precision, sensitivity to accumulation of radiometabolites, and magnitude of in vivo binding. Thus, selection between the two radioligands will be primarily determined by the logistical impact of the different half-lives of the two radionuclides (110 vs 20 min). (orig.)

Dickstein, Leah P.; Zoghbi, Sami S.; Fujimura, Yota; Imaizumi, Masao; Zhang, Yi; Pike, Victor W.; Innis, Robert B.; Fujita, Masahiro [National Institutes of Health, Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD (United States)

2011-02-15

329

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 gl...

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

2009-01-01

330

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)

1982-06-11

331

Ceylon cinnamon does not affect postprandial plasma glucose or insulin in subjects with impaired glucose tolerance.  

Science.gov (United States)

Previous studies on healthy subjects have shown that the intake of 6 g Cinnamomum cassia reduces postprandial glucose and that the intake of 3 g C. cassia reduces insulin response, without affecting postprandial glucose concentrations. Coumarin, which may damage the liver, is present in C. cassia, but not in Cinnamomum zeylanicum. The aim of the present study was to study the effect of C. zeylanicum on postprandial concentrations of plasma glucose, insulin, glycaemic index (GI) and insulinaemic index (GII) in subjects with impaired glucose tolerance (IGT). A total of ten subjects with IGT were assessed in a crossover trial. A standard 75 g oral glucose tolerance test (OGTT) was administered together with placebo or C. zeylanicum capsules. Finger-prick capillary blood samples were taken for glucose measurements and venous blood for insulin measurements, before and at 15, 30, 45, 60, 90, 120, 150 and 180 min after the start of the OGTT. The ingestion of 6 g C. zeylanicum had no significant effect on glucose level, insulin response, GI or GII. Ingestion of C. zeylanicum does not affect postprandial plasma glucose or insulin levels in human subjects. The Federal Institute for Risk Assessment in Europe has suggested the replacement of C. cassia by C. zeylanicum or the use of aqueous extracts of C. cassia to lower coumarin exposure. However, the positive effects seen with C. cassia in subjects with poor glycaemic control would then be lost. PMID:21929834

Wickenberg, Jennie; Lindstedt, Sandra; Berntorp, Kerstin; Nilsson, Jan; Hlebowicz, Joanna

2012-06-01

332

Analogic fiber optic position sensor with nanometric resolution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Lamarque, Fre?de?ric; Prelle, Christine

2002-01-01

333

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

Energy Technology Data Exchange (ETDEWEB)

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.

Miller, J.D.; de Leon, M.J.; Ferris, S.H.; Kluger, A.; George, A.E.; Reisberg, B.; Sachs, H.J.; Wolf, A.P.

1987-04-01

334

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

International Nuclear Information System (INIS)

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

1989-01-01

335

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

336

Electrical Analogy to an Atomic Force Microscope  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Kucera, O.

2010-01-01

337

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

338

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... Home Take Action Take Action at the State Level Advocacy Priorities State Priorities Federal Priorities Advocacy Accomplishments ... symptoms include the following: High blood glucose High levels of sugar in the urine Frequent urination Increased ...

339

Hyperglycemia (High Blood Glucose)  

Medline Plus

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

340

Hyperglycemia (High Blood Glucose)  

Medline Plus

Full Text Available ... a.m. to 5:00 a.m.). What are the Symptoms of Hyperglycemia? The signs and symptoms ... have ketones, do not exercise. Exercising when ketones are present may make your blood glucose level go ...

 
 
 
 
341

Hyperglycemia (High Blood Glucose)  

Medline Plus

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

342

Your Glucose Meter  

Science.gov (United States)

... Health for Women Free Publications For Women Your Glucose Meter Print and Share (PDF 164KB) En Español ... your needs. 7 Helpful Tips for Testing Your Blood Sugar Read the directions for the meter and the ...

343

All about Blood Glucose  

Science.gov (United States)

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

344

Recombinant glucose uptake system  

Energy Technology Data Exchange (ETDEWEB)

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

345

Mechanism for underestimation of isotopically determined glucose disposal  

Energy Technology Data Exchange (ETDEWEB)

Use of (3H)glucose and a one-compartment model to determine glucose kinetics frequently underestimates the rate of glucose production (Ra). To assess to what extent an isotope effect, a tracer contaminant, or inadequacy of the model was responsible, we measured glucose Ra and forearm clearance of tracer and unlabeled glucose at various concentrations of plasma insulin (approximately 50, approximately 160, and approximately 1800 microU/ml) and plasma glucose (approximately 90, approximately 160, approximately 250, and approximately 400 mg/dl) under steady-state and non-steady-state conditions. Under isotopic steady-state conditions, the clearances of tracer and unlabeled glucose across the forearm were identical, and exogenous glucose infusion rates did not differ significantly from the isotopically determined glucose Ra (10.0 +/- 1.3 vs. 10.5 +/- 1.0 mg.kg-1 fat-free mass.min-1, respectively). However, under isotopic non-steady-state conditions, the isotopically determined Ra was significantly lower than the glucose infusion rate (11.5 +/- 1.3 vs. 13.7 +/- 1.5 mg.kg-1 fat-free mass.min-1, respectively, P less than .001), and the underestimation was related to the deviation from the isotopic steady state. When (3H)glucose specific activity of plasma samples from experiments with the greatest underestimation of Ra was determined by high-performance liquid chromatography, less than 7% of the underestimation could be accounted for by a contaminant. These results indicate that inadequacy of the one-compartment model is responsible for underestimation of glucose Ra under non-steady-state conditions and that there is no detectable isotopic effect or appreciable contaminant of (3-3H)glucose. We conclude that under isotopic steady-state conditions, (3-3H)glucose is a reliable tracer for glucose kinetic studies in humans.

Yki-Jaervinen, H.C.; Consoli, A.; Nurjhan, N.; Young, A.A.; Gerich, J.E.

1989-06-01

346

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

347

An optimized analog to digital converter for WLAN analog front end  

Science.gov (United States)

A 10 bit 80 MSPS analog to digital converter optimized for WLAN analog front end is presented. In contrast to conventional 1.5 bit pipeline architecture, four optimized multi-bit multiply digital to analog converter stages are implemented. An on-chip low-noise reference buffer is proposed for SoC integration purposes, and a wide-bandwidth wide swing sample and hold amplifier is also presented for achieving a good dynamic range. The converter was fabricated in 0.18 ?m 1P6M CMOS technology, and the core area occupies approximately 0.85 mm2. Measured results show that with an 11 MHz input signal, it provides a 9.4 bit effective number of bits and a 72 dBc spurious frequency dynamic range when sampled at 80 MHz.

Mao, Ye; Yumei, Zhou; Bin, Wu; Jianhua, Jiang

2012-04-01

348

An optimized analog to digital converter for WLAN analog front end  

International Nuclear Information System (INIS)

A 10 bit 80 MSPS analog to digital converter optimized for WLAN analog front end is presented. In contrast to conventional 1.5 bit pipeline architecture, four optimized multi-bit multiply digital to analog converter stages are implemented. An on-chip low-noise reference buffer is proposed for SoC integration purposes, and a wide-bandwidth wide swing sample and hold amplifier is also presented for achieving a good dynamic range. The converter was fabricated in 0.18 ?m 1P6M CMOS technology, and the core area occupies approximately 0.85 mm2. Measured results show that with an 11 MHz input signal, it provides a 9.4 bit effective number of bits and a 72 dBc spurious frequency dynamic range when sampled at 80 MHz. (semiconductor integrated circuits)

2012-04-01

349

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

350

Direct Conversion Analog to Digital Converter.  

Science.gov (United States)

A four bit subtractor analog to digital converter provides direct conversion of analog voltage signals into binary or binary coded decimal output signals for digital display or digital signal processing. The analog to digital converter utilizes a pluralit...

W. E. Chapple

1980-01-01

351

Project for a codable central unit for analog data acquisition  

International Nuclear Information System (INIS)

The instrumentation for a 256 channel codable central processor intended for an operation in connection with a computer is presented. The computer indicates the adresses of the channels to be measured, orders the conversion, and acquires the results of measurements. The acquisition and computer coupling unit is located in a standard rock CAMAC (6 U 19inch., 25 positions); an example of configuration is given. The measurement velocity depends on the converter speed and dead time of analog circuits; for a ADC 1103 converter the total dead time is 6.5s min. The analog circuits are intended for +-10V range, the accuracy is 1/2n (2n is the number of bits). The result is acquired in words of 12 bits maximum. The information transfer and analog commutation (through integrated analog gates) are discussed

1975-05-20

352

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Cescon, Marzia; Johansson, Rolf

2012-01-01

353

Pressão arterial, glicemia capilar e medidas antropométricas em uma população Yanomámi Blood pressure, capillary glucose, and anthropometric measurements in a Yanomámi population  

Directory of Open Access Journals (Sweden)

Full Text Available Com o objetivo de avaliar o comportamento da glicemia capilar e das pressões arteriais sistólica (PAS e diastólica (PAD em função de medidas antropométricas, foram examinados 72 Yanomámi adultos na Área de Relações Intercomunitárias de Surucucus, Estado de Roraima. A pressão arterial foi mais elevada nos homens do que nas mulheres (PAS = 109,8 mm Hg e 100,2 mm Hg; PAD = 71,2 mm Hg e 63,5 mm Hg, respectivamente. Não houve valores compatíveis com a hipertensão arterial. A PAS correlacionou-se negativamente com a idade e positivamente com altura, peso, índice de massa corporal (IMC e circunferências abdominal e do quadril. O controle pelo IMC não alterou a correlação inversa entre PAS e idade. A correlação da PAS com a altura inverteu-se quando controlada pelo peso, enquanto o controle pela altura não alterou a correlação positiva entre peso e PAS. A PAD correlacionou-se positivamente com o peso e a altura. A glicemia foi significativamente mais elevada nas mulheres do que nos homens (114,1 mg/dl e 98,4 mg/dl, respectivamente. Controlando-se pelo peso, a circunferência abdominal correlacionou-se positivamente com a glicemia. Ao se controlar pela circunferência abdominal, o peso e o IMC correlacionaram-se inversamente com a glicemia. Os achados sugerem que, enquanto a PAS correlaciona-se principalmente com a massa corporal, a glicemia capilar está mais correlacionada com a concentração abdominal de gordura.Seventy-two Yanomámi Indians from Surucucus, Roraima, Brazil, were examined to evaluate the correlation between capillary glucose level (CGL, systolic and diastolic blood pressure (SBP and DBP, and anthropometrical features. Blood pressure was higher among men than women: SBP=109.8 and 100.2 mm Hg; DBP=71.2 and 63.5 mmHg, respectively. Levels compatible with hypertension were not found. SBP was correlated negatively with age and positively with height, weight, body mass index (BMI, and waist and hip circumferences. Controlling for BMI did not change the negative correlation between SBP and age. When weight was controlled, correlation between SBP and height changed to a negative value, but when height was controlled, positive correlation between weight and PAS was mantained. DBP was positively correlated with weight and height. Capillary glucose level was significantly higher among women than men: 114.1 and 98.4 mg/dl, respectively. When weight was controlled, waist circumference correlated positively with CGL. When waist circumference was controlled, weight and BMI correlated negatively with CGL. The results suggest that while blood pressure is correlated especially with body mass, capillary glucose level is more correlated with abdominal fat distribution.

Katia V. Bloch

1993-12-01

354

IDegAsp : a novel soluble insulin analogs combination  

DEFF Research Database (Denmark)

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

Ma, Zhulin; Parkner, Tina

2012-01-01

355

A MEMS viscometric sensor for continuous glucose monitoring  

Science.gov (United States)

We present a MEMS sensor aiming to enable continuous monitoring of glucose levels in diabetes patients. The device features a magnetically-driven vibrating microcantilever, which is situated in a microchamber and separated from the environment by a semi-permeable membrane. Glucose sensing is based on affinity binding principles using a solution of dextran concanavalin-A (Con A) as the sensing fluid. The glucose concentration is determined by detecting viscosity changes induced by the binding of glucose to Con A through the measurement of the cantilever's vibration parameters. The device is capable of measuring physiologically relevant glucose concentrations from 0 to 25 mM with a resolution better than 0.025 mM and a phase sensitivity better than 0.4° mM-1. The response of the sensor to glucose concentration changes has a time constant down to 4.27 min, and can be further improved with optimized device designs.

Zhao, Yongjun; Li, Siqi; Davidson, Arthur; Yang, Bozhi; Wang, Qian; Lin, Qiao

2007-12-01

356

Learning Plate Tectonics Using a Pre-Analogy Step  

Science.gov (United States)

Previous research has shown that children tend to demonstrate lower performance on analogical reasoning tasks at a causal relations level compared to most adults (Gentner & Toupin, 1986). This tendency is an obstacle that geoscience educators must overcome because of the high frequency of analogies used in geoscience pedagogy. In particular, analog models are used to convey complex systems of non-everyday/non-observable events found in nature, such as plate tectonics. Key factors in successful analogical reasoning that have been suggested by researchers include knowledge of the causal relations in the base analog (Brown & Kane, 1988; Gentner, 1988; Gentner & Toupin, 1986), and development of learning strategies and metaconceptual competence(Brown & Kane, 1988). External factors, such as guiding cues and hints have been useful cognitive supports that help students reason through analogical problems (Gick & Holyoak, 1980). Cognitive supports have been seen by researchers to decrease processing demands on retrieval and working memory (Richland, Zur, & Holyoak, 2007). We observed third and fourth graders learning about plate tectonics beginning with a pre-analogy step-a cognitive support activity a student can do before working with an analogy to understand the target. This activity was designed to aid students in developing their understanding of object attributes and relations within an analog model so that more focus can be placed on mapping the corresponding higher-order relations between the base and target. Students learned targeted concepts of plate tectonics, as measured by pre to post gains on items adapted from the Geosciences Concept Inventory. Analyses of classroom interaction showed that students used the object attributes and higher-order relations highlighted in the pre-analogy activity as resources to reason about plate boundaries and plate movement during earthquakes.

Glesener, G. B.; Sandoval, W. A.

2011-12-01

357

A mixed analog-digital pulse spectrometer  

International Nuclear Information System (INIS)

This paper presents and discusses some applications and advantages of a hybrid spectrometer system that contains a high performance Pulse-Height Analyzer (PHA) and a Digital Pulse Processor (DPP). This mixed analog-digital system, based on a TMS320C31 Digital Signal Processor (DSP), is implemented in a single board to be hosted in the Personal Computer's ISA bus. Beyond the independent use of the PHA and the DPP units, their integration allow for additional features to be performed without the need of external equipment. Among those features are pileup rejection, pulse shape discrimination, ballistic deficit correction and the capability to measure the experimental noise in order to optimize the pulse shaping parameters or to correct the pulse heights given by the analog PHA

1999-02-11

358

HAPS, a Handy Analog Programming System  

DEFF Research Database (Denmark)

HAPS (Hybrid Analog Programming System) is an analog compiler that can be run on a minicomputer in an interactive mode. Essentially HAPS is written in FORTRAN. The equations to be programmed for an ana log computer are read in by using a FORTRAN-like notation. The input must contain maximum and minimum values for the variables. The output file includes potentiometer coefficients and static-test 'measuring values.' The file format is fitted to an automatic potentiometer-setting and static-test program. Patch instructions are printed by HAPS. The article describes the principles of HAPS and emphasizes the limitations HAPS puts on equation structure, types of computing circuit, scaling, and static testing.

Højberg, Kristian Søe

1975-01-01

359

Testosterone increases GLUT4-dependent glucose uptake in cardiomyocytes.  

Science.gov (United States)

Testosterone exerts important effects in the heart. Cardiomyocytes are target cells for androgens, and testosterone induces rapid effects via Ca(2+) release and protein kinase activation and long-term effects via cardiomyocyte differentiation and hypertrophy. Furthermore, it stimulates metabolic effects such as increasing glucose uptake in different tissues. Cardiomyocytes preferentially consume fatty acids for ATP production, but under particular circumstances, glucose uptake is increased to optimize energy production. We studied the effects of testosterone on glucose uptake in cardiomyocytes. We found that testosterone increased uptake of the fluorescent glucose analog 2-(N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl)amino)-2-deoxyglucose and [(3) H]2-deoxyglucose, which was blocked by the glucose transporter 4 (GLUT4) inhibitor indinavir. Testosterone stimulation in the presence of cyproterone or albumin-bound testosterone-induced glucose uptake, which suggests an effect that is independent of the intracellular androgen receptor. To determine the degree of GLUT4 cell surface exposure, cardiomyocytes were transfected with the plasmid GLUT4myc-eGFP. Subsequently, testosterone increased GLUT4myc-GFP exposure at the plasma membrane. Inhibition of Akt by the Akt-inhibitor-VIII had no effect. However, inhibition of Ca(2+) /calmodulin protein kinase (CaMKII) (KN-93 and autocamtide-2 related inhibitory peptide II) and AMP-activated protein kinase (AMPK) (compound C and siRNA for AMPK) prevented glucose uptake induced by testosterone. Moreover, GLUT4myc-eGFP exposure at the cell surface caused by testosterone was also abolished after CaMKII and AMPK inhibition. These results suggest that testosterone increases GLUT4-dependent glucose uptake, which is mediated by CaMKII and AMPK in cultured cardiomyocytes. Glucose uptake could represent a mechanism by which testosterone increases energy production and protein synthesis in cardiomyocytes. PMID:23757167

Wilson, Carlos; Contreras-Ferrat, Ariel; Venegas, Nataly; Osorio-Fuentealba, César; Pávez, Mario; Montoya, Katherine; Durán, Javier; Maass, Rodrigo; Lavandero, Sergio; Estrada, Manuel

2013-12-01

360

Labelled antibody assays for measuring free triiodothyronine: evaluation and comparison with a labelled analog method. Dosages de la triiodothyronine libre utilisant un anticorps marque: evaluation et comparaison a un dosage avec traceur analogue  

Energy Technology Data Exchange (ETDEWEB)

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

Sapin, R.; Gasser, F.; Schlienger, J.L.; Chambron, J. (Centre Hospitalier Universitaire, 67 - Strasbourg (France))

1993-01-01

 
 
 
 
361

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

1986-01-01

362

Variable Classifications of Glycemic Index Determined by Glucose Meters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2010-01-01

363

A Comparative Effectiveness Analysis of Three Continuous Glucose Monitors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVE To compare three continuous glucose monitoring (CGM) devices in subjects with type 1 diabetes under closed-loop blood glucose (BG) control. RESEARCH DESIGN AND METHODS Six subjects with type 1 diabetes (age 52 ± 14 years, diabetes duration 32 ± 14 years) each participated in two 51-h closed-loop BG control experiments in the hospital. Venous plasma glucose (PG) measurements (GlucoScout, International Biomedical) obtained every 15 min (2,360 values) were paired in time with corresp...

Damiano, Edward R.; El-khatib, Firas H.; Zheng, Hui; Nathan, David M.; Russell, Steven J.

2013-01-01

364

An electrophysiological investigation of glucose effects in the Flanker task  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Behavioural studies have indicated that response times on complex reaction time tasks are faster if blood glucose concentrations are slightly elevated above normal (Donohoe & Benton, 2000). Such tasks involve several cognitive processing stages but it is not clear which of these stages are speeded after glucose administration. In order to investigate this problem we have used a double blind repeated measures design for the administration of glucose and placebo drinks. Participants performed a...

Seiss, E.; Hope, C.; Dean, Pja; Sterr, A.

2010-01-01

365

Strong glucose dependence of electron current in human monocytes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reactive oxygen species (ROS) production by human monocytes differs profoundly from that by neutrophils and eosinophils in its dependence on external media glucose. Activated granulocytes produce vast amounts of ROS, even in the absence of glucose. Human peripheral blood monocytes (PBM), in contrast, are suspected not to be able to produce any ROS if glucose is absent from the media. Here we compare ROS production by monocytes and neutrophils, measured electrophysiologically on a single-cell ...

Musset, Boris; Cherny, Vladimir V.; Decoursey, Thomas E.

2012-01-01

366

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

367

An ozone budget for the UK: using measurements from the national ozone monitoring network; measured and modelled meteorological data, and a 'big-leaf' resistance analogy model of dry deposition  

International Nuclear Information System (INIS)

A method of calculating a mass budget for O3 in the UK boundary layer is presented which shows that the spatial scale of the UK is small relative to the footprint of the atmosphere influenced by UK emissions. - Data from the UK national air-quality monitoring network are used to calculate an annual mass budget for ozone (O3) production and loss in the UK boundary layer during 1996. Monthly losses by dry deposition are quantified from 1 kmx1 km scale maps of O3 concentration and O3 deposition velocities based on a 'big-leaf' resistance analogy. The quantity of O3 deposition varies from ?50 Gg-O3 month-1 in the winter to over 200 Gg-O3 month-1 in the summer when vegetation is actively absorbing O3. The net O3 production or loss in the UK boundary layer is found by selecting days when the UK is receiving 'clean' Atlantic air from the SW to NW. In these conditions, the difference in O3 concentration observed at Mace Head and a rural site on the east coast of the UK indicates the net O3 production or loss within the UK boundary layer. A simple box model is then used to convert the concentration difference into a mass. The final budget shows that for most of the year the UK is a net sink for O3 (-25 to -800 Gg-O3 month-1) with production only exceeding losses in the photochemically active summer months (+45 Gg-O3 month-1)

2003-05-01

368

Production of glucose isomerase  

Energy Technology Data Exchange (ETDEWEB)

Glucose isomerase is produced by culturing Streptomyces strains in the presence of xylulose. Thus, Streptomyces YT-5 was incubated in a culture broth containing corn steep liquor 3 and CoCl/sub 2/.6H/sub 2/O 0.024% in the presence of 0.5% xylulose and incubated at 30/sup 0/ for 35 hours. The accumulation of glucose isomerase reached 16.5 units/ml, but only 0.3 units/ml in the absence of xylulose. The production of glucose isomerase was also stimulated by 0.5% xylose (18.8 units/ml) or 0.5% xylan (21.2 units/ml).

1981-07-18

369

Analog Performance Prediction Based on Archimedean Copulas Generation Algorithm  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Testing analog circuits is a complex and very time consuming task. In contrary to digital circuits, testing analog circuits needs different configurations, each of them targets a certain set of output parameters which are the performances and the test measures. One of the solutions to simplify the test task and optimize test time is the reduction of the number of to-be-tested performances by eliminating redundant ones. However, the main problem with such a solution is the identification of re...

2011-01-01

370

Performance report for Stanford/SLAC microstore Analog Memory Unit  

International Nuclear Information System (INIS)

Tests of a newly developed Analog Memory Unit (AMU) are described. The device contains 256 analog storage cells consisting of pass transistors, a storage capacitor and a differential read out buffer. By addressing the storage cells sequentially, the shape of the signal present at the input can be recorded in time. Fast response and good amplitude resolution were the design goals for the development. Measurements on individual devices are presented and the status of hybridized subsystems containing eight AMUs discussed

1985-02-01

371

IMMOBILIZATION OF GLUCOSE OXIDASE IN SILICA SOL-GEL FILM FOR APPLICATION TO BIOSENSOR AND AMPEROMETRIC DETERMINATION OF GLUCOSE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, an electrochemical biosensor was developed by using a sol-gel coating solution. The modified platinum electrode used in the study was constructed by immobilization of glucose oxidase under a layer of sol-gel film. The sol-gel coating solution was prepared by using GLYMO, TEOS, and MTEOS. Electrochemical measurements were carried out amperometrically by determining hydrogen peroxide produced by the enzymatic reaction between glucose and glucose oxidase. The amperometric response...

Dem Rkiran, N. Zamett N.; ERGUN EK?NC?; MELTEM AS?LTÜRK

2012-01-01

372

Measurement of regional cerebral hemocirculation, oxygen and glucose metabolism in patients with untreated high grade gliomas using positron emission tomography (PET)  

International Nuclear Information System (INIS)

Hemocirculatory and metabolic indices of regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction fraction (rOEF), cerebral oxygen consumption (rCMRO2) and cerebral glucose consumption (rCMRGl) were studied in eight patients with untreated high grade gliomas. Regions of interest (ROIs) were focused on the lesions corresponding to contrast enhanced area, the central low density area of the tumor and the peritumoral low density area on CT scans. In the viable portion of gliomas, rCBV (5.20±1.18ml/100ml, mean±SD, n=8) was significantly higher than that of the contralateral gray matter (P2 (1.66±0.45ml/100ml/min) values markedly decreased (P2, rCMRG1 values decreased significantly from the viable portion and the contralateral gray matter. rOFF was markedly reduced in the central low density area, compared with that of the peritumoral low density area. The reduction suggested that tissue metabolic function was the first to fail, accompanied by autoregulatory impairment of vessels. In the peritumoral low density area, rCBF, rCBV, rCMRO2, rCMRG1 values were also lower than in the viable portion of gliomas and the contralateral gray matter. However, the rOEF was similar to the contralateral gray matter. A matched reduction of rCBF and rCMRO2 implies tissue metabolic failure and infiltration of tumor cells. (J.P.N.)

1989-01-01

373

Glucose-6-phosphatase deficiency  

Directory of Open Access Journals (Sweden)

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

Labrune Philippe

2011-05-01

374

Theory of Analogous Force on Number Sets  

CERN Document Server

A general statistical thermodynamic theory that considers given sequences of x-integers to play the role of particles of known type in an isolated elastic system is proposed. By also considering some explicit discrete probability distributions p_{x} for natural numbers, we claim that they lead to a better understanding of probabilistic laws associated with number theory. Sequences of numbers are treated as the size measure of finite sets. By considering p_{x} to describe complex phenomena, the theory leads to derive a distinct analogous force f_{x} on number sets proportional to $(\\frac{\\partial p_{x}}{\\partial x} )_{T}$ at an analogous system temperature T. In particular, this yields to an understanding of the uneven distribution of integers of random sets in terms of analogous scale invariance and a screened inverse square force acting on the significant digits. The theory also allows to establish recursion relations to predict sequences of Fibonacci numbers and to give an answer to the interesting theoreti...

Canessa, E

2003-01-01

375

Natural analogs for Yucca Mountain  

International Nuclear Information System (INIS)

High-level radioactive waste in the US, spent fuels from commercial reactors and nuclear materials generated by defense activities, will remain potentially hazardous for thousands of years. Demonstrable long-term stability of certain geologic and geochemical systems motivates and sustains the concept that high-level waste can be safely isolated in geologic repositories for requisite periods of time. Each geologic repository is unique in its properties and performance with reguard to isolation of nuclear wastes. Studies of processes analogous to waste-form alteration and radioelement transport in environments analogous to Yucca Mountain are being conducted at two sites, described in this article to illustrate uses of natural analog data: the Nopal I uranium deposit in the Sierra Pena Blanca, Mexico, and the Akrotiri archaeological site on the island of Santorini, Greece

1995-11-01

376

Glucose assay with extended concentration range by flow-through enzyme enthalpymeter  

Energy Technology Data Exchange (ETDEWEB)

The possibility of extending measurable concentration range of glucose in a flow-through enthalpymeter with immobilized glucose oxidase by supplying the column with additional oxygen was examined. (orig.).

Sugier, H.; Kurczewski, J. (Technical Univ., Lodz (Poland). Inst. of General Food Chemistry)

1992-04-01

377

Noninvasive blood glucose monitoring with laser diode  

Science.gov (United States)

The non-invasive measurement of blood sugar level was studied by use of near infrared laser diodes. The in vitro and in vivo experiments were carried out using six laser diodes having wavelengths range from 1550 nm to 1750nm. Several volu