In-vitro glucose testing

Electrochemical Sensors, Biosensors and Their Biomedical Applications 

FIGURE 3.4 A typical commercial strip for self-testing of blood glucose (based on a biosensor manufactured by Abbott Inc.) (see Plate 1 for the color version). 

Major commercial electrochemical systems for self-monitoring of blood glucose 

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In vitro diagnostie test systems Requirements for blood glucose monitoring systems for self-testing in managing diabetes mellitus... 

Medication can be delivered via the eye in the form of eyedrops or in an ocular device. Sodium or zinc insulin was incorporated into a Gelfoam sponge-based device. An in vitro dissolution test indicated that the release of insulin from the device was proportional to the flow rate of the dissolution medium. An in vivo dissolution experiment provided support for the hypothesis that there was a direct relationship between the prolonged pharmacological response to insulin and its release from the device. The ocular device with or without the aid of an enhancer was placed in the eye of rabbits as an ocular insert and produced a uniform blood glucose-lowering effect of 60% over 8h. The blood glucose... 

Many natural drugs and traditional preparations are used in traditional medicine as antidiabetics and several active compounds have been identified by in vivo bioassay using experimental diabetic animal induced by alloxan or streptozocin or by using the oral sucrose tolerance test (one of the animal model of insulin-dependent diabetes mellitus) and by in vitro bioassay testing glucose transport activity. 

Metabolic Functions. Chromium (ITT) potentiates the action of insulin and may be considered a cofactor for insulin (137,138). In in vitro tests of epididymal fat tissue of chromium-deficient rats, Cr(III) increases the uptake of glucose only in the presence of insulin (137). The interaction of Cr(III) and insulin also is demonstrated by experimental results indicating an effect of Cr(III) in translocation of sugars into ceUs at the first step of sugar metaboHsm. Chromium is thought to form a complex with insulin and insulin receptors (136). 

The effects of D-glucose observed in vivo are not well reproduced in vitro. Madara [203] reported that cytoskeletal contraction and enhanced paracellular permeability were observed only in an in situ perfusion preparation and not in an isolated tissue preparation. Although its in vivo effect was not tested, 25 mM D-glucose, an effective concentration in the jejunum [47], failed to enhance the in vitro transport of sotalol (log PC = -0.62), atenolol (log PC = 0.16), or nadolol (log PC = 0.93) across the isolated conjunctiva [213], For a similar reason and possibly due to the absence of a Na+-glucose cotransporter in the cornea, 25 mM D-glucose was ineffective in increasing the corneal transport of these three drugs. 

Chapter 4 describes the in vitro reaction of glucose wifh demineralized dentin. Preliminary tests revealed that use of disfilled insfead of deionized water accelerated browning, consistent with the effect of frace metals on the Maillard reaction. The yellow discolored slices were more resistant than controls to pepsin-mediated breakdown, but not to trypsin-mediated breakdown. It would be worthwhile to investigate proteolysis of denfin collagen covalently bound by the Maillard reaction to proteins, which penetrate into a caries lesion. 

Directive 98/79/EC on in vitro diagnostics (TVDs ) came into force on 7 June 2000 and is mandatory from 7 December 2003. This covers products such as pregnancy tests, blood glucose monitoring and tests for transmissible diseases. 

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