Glucose concentration in blood

The glucose sensor is one of the best known everyday applications of the elec-troanalytical ideas we have met in this chapter. Such sensors provide a fast and reliable determination of the glucose concentration in blood. People with diabetes frequently require such assays, and pathology laboratories in hospitals and clinics also need these data, so analyses of this type need to be quick, cheap and above all, accurate and reliable. 

The current is proportional to the concentration of H2Oz, which, in turn, is proportional to the glucose concentration in blood (Figure 17-11). 

Chlorpropamide Less glycosuria Karela decreases glucose concentrations in blood... 

Sulphonylureas have been used for the treatment of Type-II diabetes for more than 30 years. Two actions are thought to be responsible for their ability to lower glucose concentration in blood (1) their action on B-cells which causes insulin secretion (2) the so-called extrapancreatic effects which have been mainly demonstrated in in vitro experiments. 

Dzyadevich, S. V. (1999). Soldatkin application of enzyme field-effect transistors for determination of glucose concentrations in blood serum. Biosens Bioelectron 14, 283-287. 

Measurements that are dependent on each other provide correlated data. Typically, time-dependent processes, such as the time series of glucose concentrations in blood, are of this type of data. Correlated measurements caimot be characterized by the same methods used for description of random independent observations. They require methods of time series analysis where it is assumed that the measurements are realizations of a stochastic process and where they are statistically dependent (Section 3.2). 

H. OelschlRger A very severe problem of public health is the increasing number of patients who are suffering from diabetes. Do you see any chance of realizing the construction of an electrode which would be able, after implantation, to measure the glucose concentration in blood over a long period If you should succeed, then you would have solved the problem of the insulin injector. And I think that is more important than to measure dopamine concentration in rat brains ... 

Three points about this definition merit discussion. First, the concentration c may be near zero even when the solute concentration in the blood is more than zero. This is especially true for solutes whose properties, like solubility, are pH dependent. For the case of glucose, however, the solubility in chyme and blood is about the same, and so c will be close to the actual glucose concentration in blood. 

Hypoglycemic agent. A drug that lowers glucose concentrations in the blood. 

Most of the recent attention has been given to the development of subcutaneously implantable needle-type electrodes [14, 15, 34, 38], Such devices track blood glucose levels by measuring the glucose concentration in the interstitial fluid of the subcutaneous tissue (assuming the ratio of the blood/tissue levels is constant). Subcutaneously implantable devices are commonly designed to operate for a few days and be replaced by the patient. Success in this direction has reached the level of short-term human implantation ... 

D. Schmidtke, A. Freeland, A. Heller, and R. Bonnecaze, Measurement and modeling of the transient difference between blood and subcutaneous glucose concentrations in the rat after injection of insulin. Proc. Natl. Acad. Sci. U.S.A. 95, 294-299 (1998). 

In contrast to other tests that measure glucose, this method is truly non-invasive. The fluid for doing the test in fact is tears, as the glucose concentration in tears is known to correlate with the blood glucose concentration. Manufacturing is scheduled by 2010 with clinical trials currently being conducted and regulatory approval scheduled in 2009. 

Glucose entry into most cells is concentration driven and independent of sodium. Four glucose transporters (GLUT) are listed in Table 1-12-1. They have different afiinities for glucose coinciding with their respective physiologic roles. Normal glucose concentration in peripheral blood is 4-8 mM (70-140 m dL). 

GLUT 4 is in adipose tissue and muscle and responds to the glucose concentration in peripheral blood. The rate of glucose transport in these two tissues is increased by insulin, which stimulates the movement of additional GLUT 4 transporters to the membrane by a mechanism involving exocytosis (Figure 1-12-1). 

In summary, an increase in the glucose concentration in the portal blood results in an increase in the hepatic concentration of glucose which leads to three changes ... 

The role of glucagon and insulin in the regulation of glu-coneogenesis, along with other factors, is to maintain the blood glucose concentration in starvation. This is discussed in Chapter 12. 

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