Showing papers on "Glucose Measurement published in 1982"

Blood glucose control apparatus and method

Abstract: In a method and apparatus for controlling the concentration of glucose in the blood stream of a subject at a desired level (BI) including controlling the supply of insulin (IR) by periodically measuring the blood glucose concentration (G) and selecting a predetermined basal infusion rate (RI) for the desired level, the step of selecting a predetermined basal infusion rate comprises periodically searching for the value of the basal infusion rate RI required for BI in accordance with RI=RI.sub.LAST (GY/BI) where (GY) is the present blood glucose level corrected to fit a least squares regression line, when the slope of the least squares regression line fit for the last five G values is less than 0.5 and GY is within ±50% of the desired BI level, and wherein the period between searches is equal to or greater than the period between glucose measurements.

Use of a physiologic pharmacokinetic model of glucose homeostasis for assessment of performance requirements for improved insulin therapies.

Abstract: Methods are presented for assessing insulin therapies using a physiologic pharmacokinetic model of glucose homeostasis in man. The model is composed of simultaneous differential equations that represent physiologic compartments and spaces in which glucose and insulin are distributed and undergo metabolic reactions. The model is used to simulate clinical experiments in which blood glucose concentration is controlled by artificial device therapies. Predictions of the theoretical model for responses of normal and diabetic individuals to standard intravenous and oral glucose tolerance tests are compared to clinical data. Reasonable agreement is obtained between predictions of the computer simulations and clinical data for normal individuals. The responses of a diabetic person to oral glucose tolerance tests are simulated by removal of the pancreas from the glucose homeostasis model and introduction of insulin into the model by a prescribed therapy. Model simulations reaffirm expectations concerning the poor blood glucose control attainable by intramuscular insulin injection. Simulations of blood glucose regulation by an artificial pancreas using closed-loop feedback control for controlling insulin delivery rate reveal hyperinsulinemia that results in a net shift in the deposition of a glucose load from liver to peripheral tissues. Simulations of this system in which the time delay for glucose measurement is varied from 1.5 to 30 min show that increases in sensor delay result in progressive loss in glucose regulation, exacerbation of hyperinsulinemia, and increased insulin requirements.

A Miniature Fiberoptic pH Sensor Potentially Suitable for Glucose Measurements

Abstract: A fiberoptic sensor that we have developed for measuring physiologic pH is a potentially useful model for similar probes for other important applications such as monitoring glucose in the body. A fiberoptic probe has important advantages over an electrode in safety, reliability, applicability, and cost. The pH probe is described, with suggested approaches for making a device for glucose measurement.

Continuous maternal glucose measurements and fetal glucose and insulin levels after administration of terbutaline in term labor

Abstract: Maternal blood glucose and fetal blood glucose and insulin levels were studied in 16 women at full-term labor after administration of terbutaline 250 microgram i.v. The maternal blood glucose level was registered by a continuous blood glucose monitoring unit. In all patients studied, the terbutaline injection was followed by a rise in maternal blood glucose within 15 min, lasting for at least one hour. The fetal glucose levels paralleled those of the mothers, but on a lower level. None of the infants demonstrated hypoglycemia during the first 90 min after birth. We conclude that terbutaline administrated in this way has a direct effect on the maternal blood glucose release, and report that no harmful effects on fetal carbohydrate metabolism could be demonstrated.

Glucose measurement errors in enzymic starch hydrolysates at high enzyme-glucose weight ratios

Abstract: The 3,5-dinitrosalicylic acid (DNS), o-toluidine, and glucose oxidase methods accurately measured concentrations of standard glucose solutions in the absence of the starch hydrolyzing enzymes Diazyme (amyloglucosidase) and Clarase (α-amylase). In the presence of high enzyme concentrations, particularly at low glucose concentrations, glucose oxidase and o-toluidine somewhat underestimated standard glucose concentrations while DNS overestimated the glucose concentration by 100%. DNS also overestimated glucose in hydrolysates of standard potato starch. Glucose recovery was estimated at almost 200% of that given by glucose oxidase when enzyme starch weight ratios were 9:1 or more. Glucose was underestimated by o-toluidine in starch hydrolysates in the presence of Diazyme at high enzyme-starch weight ratios. DNS similarly overestimated glucose in starch hydrolysates from white spruce (Picea glauca (Moench.) Voss) and some other species, as enzyme-starch weight ratios increased. The o-toluidine and glucose oxidase reactions were more reliable. Overestimation of the DNS reaction was not improved by treating the glucose-enzyme solutions with anion or cation exchange resins or by removing the enzyme prior to measurement.

A Comparison of Three Methods for the Estimation of Capillary Blood Glucose in Filter Paper Spots

Abstract: A comparison has been made between three methods for measuring capillary blood glucose collected on filter paper, including a new method using a Beckman glucose analyser 2. The methods are suitable for use with capillary blood spots collected onto filter paper for monitoring the control of diabetic patients. Their accuracy, precision, and recovery of glucose were similar. Glucose measurement with the Beckman glucose analyser 2 involves elution of the dried blood spots with 2% trichloroacetic acid and injection of a fraction of the eluate into the analyser. The method provides a simple and rapid alternative procedure for laboratories that do not have a heavy workload for this type of assay.

Possibility for an Immobilized Flavin Fuel Cell Electrode for Glucose Measurements

Abstract: Preliminary work is described on the attachment of riboflavin to solid carbon via a coupling group that should provide a pathway for easy electron transfer. Such an approach, when extended to the flavin cofactor portion of glucose oxidase, has the possibility of forming a fuel cell electrode of high specificity for glucose and in which the current would be related to the concentration of glucose.

Chemically Sensitive Field Effect Transistor as a Potential Implantable Glucose Sensor

Abstract: An overview of the present status of development and application of chemically sensitive field effect transistors (CHEMFETs) is presented. Sensors potentially suitable for glucose measurement are discussed.