scholarly journals Glucose Determination by Means of Steady-state and Time-course UV Fluorescence in Free or Immobilized Glucose Oxidase

Sensors ◽  
2007 ◽  
Vol 7 (11) ◽  
pp. 2612-2625 ◽  
Author(s):  
Paola De Luca ◽  
Maria Lepore ◽  
Marianna Portaccio ◽  
Rosario Esposito ◽  
Sergio Rossi ◽  
...  
Keyword(s):  
Steady State ◽  
Glucose Oxidase ◽  
Time Course ◽  
Glucose Determination ◽  
Uv Fluorescence ◽  
Immobilized Glucose Oxidase

scholarly journals Performance of Three Enzymic Methods for Filter Paper Glucose Determination

1984 ◽  
Vol 21 (5) ◽  
pp. 411-416 ◽  
Author(s):  
J M Burrin ◽  
C P Price
Keyword(s):  
Glucose Oxidase ◽  
Filter Paper ◽  
Time Course ◽  
Glucose Dehydrogenase ◽  
Home Monitoring ◽  
Diabetic Patients ◽  
Trichloracetic Acid ◽  
Elution Time ◽  
Glucose Determination ◽  
Blood Spots

Collection of blood spots on filter paper offers a practical alternative for home monitoring of diabetic patients. We have compared the merits of three protein precipitants, trichloracetic acid (TCA), perchloric acid (PCA) and sulphosalicylic acid (SSA) for the elution of glucose from the filter paper, and their subsequent effects on three enzymic methods, glucose dehydrogenase (GDH), hexokinase (HK), and glucose oxidase (GOD) for the determination of glucose using a microcentrifugal analyser. The combination of TCA elutant with the GDH method was superior with respect to time course of reaction and elution time from the filter paper, and was chosen for routine use. Within- and between-batch precision for this method was 2·7% and 3·2% respectively at normal glucose concentrations. Recovery of glucose added to whole blood was 110 ± 5%. Comparison with an automated glucose oxidase method for plasma glucose gave a slope of 1·1, intercept of −0·7 and a correlation coefficient of 0·9 ( n = 64). We conclude that the combination of TCA and glucose dehydrogenase provides a robust, precise and accurate method for the quantitation of glucose in filter-paper blood spots. The procedure offers increased sensitivity and better precision than GOD methods. The use of TCA as elutant gives a faster elution time and has the least effect on any of the enzymic methods.

Gold nanoparticles-coated eggshell membrane with immobilized glucose oxidase for fabrication of glucose biosensor

2011 ◽  
Vol 152 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Baozhan Zheng ◽  
Shunping Xie ◽  
Lei Qian ◽  
Hongyan Yuan ◽  
Dan Xiao ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Glucose Oxidase ◽  
Glucose Biosensor ◽  
Eggshell Membrane ◽  
Immobilized Glucose Oxidase

Inward rectification in rat nucleus accumbens neurons

1989 ◽  
Vol 62 (6) ◽  
pp. 1280-1286 ◽  
Author(s):  
N. Uchimura ◽  
E. Cherubini ◽  
R. A. North
Keyword(s):  
Steady State ◽  
Nucleus Accumbens ◽  
Time Course ◽  
Potassium Conductance ◽  
Resting Potential ◽  
Inward Rectification ◽  
Resting Membrane Potential ◽  
Potential Range ◽  
Inward Current ◽  
Rat Nucleus Accumbens

1. Intracellular recordings were made from neurons in slices cut from the rat nucleus accumbens septi. Membrane currents were measured with a single-electrode voltage-clamp amplifier in the potential range -50 to -140 mV. 2. In control conditions (2.5 mM potassium), the resting membrane potential of the neurons was -83.4 +/- 1.1 (SE) mV (n = 157). Steady state membrane conductance was voltage dependent, being 34.8 +/- 1.7 nS (n = 25) at -100 mV and 8.0 +/- 0.7 nS (n = 25) at -60 mV. 3. Barium (1 microM) markedly reduced the inward rectification and caused a small inward current (40.6 +/- 8.7 pA, n = 8) at the resting potential. These effects became larger with higher barium concentrations, and, in 100 microM barium, the current-voltage relation was straight. 4. The block of the inward current by barium (at -130 mV) occurred with an exponential time course; the time constant was approximately 1 s at 1 microM barium and less than 90 ms with 100 microM. Strontium had effects similar to those of barium, but 1000-fold higher concentrations were required. Cesium chloride (2 mM) and rubidium chloride (2 mM) also blocked the inward rectification; their action reached steady state within 50 ms. 5. It is concluded that the nucleus accumbens neurons have a potassium conductance with many features of a typical inward rectifier and that this contributes to the potassium conductance at the resting potential.

Faster adjustment of O2 uptake to the energy requirement of exercise in the trained state

1978 ◽  
Vol 44 (6) ◽  
pp. 877-881 ◽  
Author(s):  
R. C. Hickson ◽  
H. A. Bomze ◽  
J. O. Hollozy
Keyword(s):  
Steady State ◽  
Exercise Training ◽  
Training Program ◽  
Endurance Exercise ◽  
Time Course ◽  
Energy Requirement ◽  
Constant Load ◽  
O2 Uptake ◽  
Endurance Exercise Training

The purpose of this study was to determine the effect of endurance exercise training on the time course of the increase in VO2 toward steady state in response to submaximal constant load work. Seven men participated in a strenuous program of endurance exercise for 40 min/day, 6 days/wk for 10 wk. Their average VO2max increased from 3.29 liters before training to 4.53 liters at the end of the training program. VO2 was measured continuously on a breath-by-breath basis at work rates requiring 40%, 50%, 60%, or 70% of VO2max before training. After training the subjects were retested both at the same absolute and the same relative work rates. The increases in VO2 toward steady state occurred more rapidly in the trained than in the untrained state both at the same absolute and at the same relative work rates. The finding that O2 uptake rises to meet O2 demand more rapidly in the trained than in the untrained state provides evidence that the working muscles become less hypoxic at the onset of exercise of the same intensity after training.

Colorimetric Glucose Assay Based on Magnetic Particles Having Pseudo-peroxidase Activity and Immobilized Glucose Oxidase

2016 ◽  
Vol 58 (5) ◽  
pp. 373-380 ◽  
Author(s):  
Pavla Martinkova ◽  
Radka Opatrilova ◽  
Peter Kruzliak ◽  
Igor Styriak ◽  
Miroslav Pohanka
Keyword(s):  
Glucose Oxidase ◽  
Peroxidase Activity ◽  
Magnetic Particles ◽  
Glucose Assay ◽  
Immobilized Glucose Oxidase

Estimation of the rate of appearance in the non-steady state with a two-compartment model

1992 ◽  
Vol 263 (2) ◽  
pp. E400-E415 ◽  
Author(s):  
A. Mari
Keyword(s):  
Steady State ◽  
Time Course ◽  
Specific Activity ◽  
Glucose Production ◽  
Compartment Model ◽  
New Method ◽  
Two Compartment Model ◽  
Glucose Clamp Technique ◽  
Glucose Output ◽  
The Relationship

A simple tracer-based method for calculating the rate of appearance of endogenous substances in the non-steady state, free from the inconsistencies of Steele's equation, is still lacking. This paper presents a method based on a two-compartment model by which the rate of appearance can be calculated with only a modest increase in complexity over Steele's approach. An equation is developed where the rate of appearance is expressed as a sum of three terms: a steady-state term, a term for the first compartment, and a term for the second compartment. The formula employs three parameters and makes the relationship between rate of appearance and specific activity changes explicit. An equation is also provided for estimating the error of the method in each individual run. The algorithm can be implemented with a spreadsheet on a personal computer. Simulated and experimental data obtained by the hyperinsulinemic euglycemic glucose clamp technique were used as a test. The accuracy with which the time course of glucose production could be reconstructed was clearly better than that using Steele's equation. Marked negative values for endogenous glucose output were calculated with Steele's equation but not with the new method. The characteristics of generality, simplicity, and accuracy and the availability of an error estimate make this new method suitable for routine application to non-steady-state tracer analysis.

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