Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An intravenous glucose sensor was implanted in six dogs for 1-15 wk. The glucose sensor is a flexible cylinder, approximately 0.2 cm diam and 30 cm long, with a tip containing immobilized glucose oxidase and catalase coupled to a potentiostatic O2 sensor. The sensor and a similar O2 reference sensor were implanted in the superior vena cava near the entrance of the right atrium. The sensor response was conveyed externally either by a telemetry system implanted nearby, surgically accessed leads, or chronically maintained percutaneous leads. Summing over the six implants, there was a total implantation period of 333 days during which glucose sensors were functional on demand. The sensor response showed agreement with conventionally assayed blood samples after accounting for a response lag. Sensor response to glucose showed little change over the implant period. Biocompatibility, enzyme lifetime, O2 availability, O2 sensor stability, and biochemical interference were not limitations. Results demonstrated that this sensor can function effectively as an implant in dogs for a period of months and has the potential for long-term operation.
Diabetes 1990 Dec
PMID:Application of chronic intravascular blood glucose sensor in dogs. 224 76

Enzymatic glucose sensors are based on the amperometric detection of an oxidable species generated during the oxidation of glucose by glucose oxidase. This measurement usually requires a working electrode (anode), an auxiliary electrode (cathode), and a reference electrode, the function of the latter being to keep constant the working potential of the anode, which is responsible for current generation. However, in the needle-type glucose sensors proposed so far, the reference electrode is missing, and its function is performed by the auxiliary electrode. We investigated, in vitro and in vivo in rats, the ability of several cathode-needle materials to behave as a reference electrode in two-electrode glucose sensors, i.e., to present a stable auxiliary electrode potential. In vitro, when glucose concentration was raised from 0 to 30 mM, the auxiliary potential of both gold- and silver-coated sensors presented a cathodic drift, whereas that of silver/silver chloride-coated sensors remained stable. In vivo, during insulin-induced hypoglycemia (5.9-2.4 mM), the auxiliary potentials of all sensors remained stable, whereas during glucose infusion (mean blood glucose concentration 11.2 mM), the auxiliary potentials of both gold- and silver-coated sensors presented an anodic drift, whereas those of silver/silver chloride-coated sensors remained stable. We also indirectly quantified the changes in sensor response induced by variations in the working potential in vitro and in vivo, simulating those that might be produced by a drift in the auxiliary potential. Such changes in the working potential could bring about a 30% unspecific variation in sensor response. We conclude that improvements in sensor analytical characteristics should be obtained with silver/silver-chloride-coated cathodes.
Diabetes 1989 Feb
PMID:In vitro and in vivo stability of electrode potentials in needle-type glucose sensors. Influence of needle material. 264 39

Miniature, amperometric glucose sensors were constructed for implantation in the subcutaneous tissue of normal and insulin-dependent diabetic subjects. To minimise dependence on fluctuating tissue oxygen tension, we employed the technology of mediated electron transfer, with 1,1'-dimethylferrocene acting as the redox shuttle between immobilized glucose oxidase and a platinum base electrode. In 6 normal subjects, the subcutaneous sensor responses mirrored the simultaneously-measured changes in blood glucose concentration after a 75 g oral glucose load and after intravenous injection of 0.15 U/kg short-acting insulin, though increases and decreases in the sensor output were slower than the glycaemic changes. The mean peak delay in sensor response after the oral glucose was 40 min (range 0-45 min) and the delay in the hypoglycaemic nadir was 4 min (range 0-15 min). In 5 insulin-dependent diabetic subjects, spontaneous and induced hypoglycaemia was detectable by the implanted sensor. In addition, marked and frequent oscillations in the sensor current occurred in several normal and diabetic individuals as the blood glucose fell below about 1.9 mmol/l. These oscillations were present in a diabetic subject who had lost adrenergic warning symptoms to hypoglycaemia. Continuous metabolic monitoring in diabetes, particularly the detection of hypoglycaemia, may be possible with implanted sensors based on this technology.
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PMID:In vivo molecular sensing in diabetes mellitus: an implantable glucose sensor with direct electron transfer. 266 12

In North America, gestational diabetes mellitus (GDM) is diagnosed from a 100-g oral glucose tolerance test (OGTT) with criteria proposed by the National Diabetes Data Group (NDDG). These criteria were derived in the 1950s from an unrepresentative sample of women tested predominantly in the latter stages of pregnancy. The original studies did not check for reproducibility of OGTT results. Measurements were made with the Somogyi-Nelson whole-blood glucose technique, and test translation errors are present in the threshold values proposed for modern plasma glucose oxidase methods. Whereas GDM is now diagnosed with a view to adverse maternal-fetal outcomes, the criteria were chosen to reflect maternal risk of developing glucose intolerance as shown by a 75-g OGTT in the nonpregnant state over the ensuing 8 yr. For that outcome, the positive predictive value of the criteria was only 36.1%, and this is a marked overestimate, because the study cohort was a highly selected group with an increased incidence of glucose intolerance both during and after pregnancy. The criteria are also conceptually flawed in that they impose a dichotomous definition of normal and abnormal on gestational glucose tolerance, when the risk of adverse maternal-fetal outcomes and later diabetes mellitus should logically be graded upward with higher values on the gestational OGTT and with the degree of fasting hyperglycemia. Although NDDG criteria merit continued use for lack of a better alternative, new diagnostic criteria for GDM should be derived and validated.
Diabetes Care 1989 Sep
PMID:Diagnosing gestational diabetes mellitus. Is the gold standard valid? 146 27

Interest in sweetening agents is encouraging manufacturers and researchers to find a safe substance to maintain the life quality of diabetics. The popularity of sweetened food items has increased recently in Taiwan. The glycemic index of fructose has been reported to be 20%, much lower than most carbohydrate foods. A high-fructose corn syrup (HFCS) has come onto the market of sweetening agents and has been proposed as a low-cost substitute for fructose in dietetic management of diabetes. The aim of this study was to compare the glycemic effects of HFCS and glucose to see if there is a place for high-fructose corn syrup in diabetic management. In 8 normal and 21 non-insulin dependent diabetes mellitus (NIDDM) subjects, we performed oral tolerance tests. After an overnight fast, the subjects were given either 75g of glucose or an equivalent amount of HFCS containing 75g of carbohydrate. Blood was sampled before and at 30, 60, 90, 120 and 180 minutes after the glucose load. Blood glucose was analyzed by the glucose oxidase method using YSI 23 A (Yellow-Springs Intrument). The insulin and C-peptide were measured by RIA kits from Daiichi. The area under the curves (AUC) was calculated for plasma glucose, immunoreactive insulin (IRI) and immunoreactive C-peptide (IRCP). The results showed that the glycemic effect of HFCS was 73% of glucose. The AUC of IRI after HFCS was 56% of that of glucose. The AUC of IRCP after HFCS was 57% of that of glucose. The high glycemic index of HFCS in our study does not support the use of HFCS as a substitute for fructose.
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PMID:Effects of high-fructose (90%) corn syrup on plasma glucose, insulin, and C-peptide in non-insulin-dependent diabetes mellitus and normal subjects. 269 93

Within the Targeted Programme of the Italian National Research Council "Preventive and Rehabilitative Medicine" subproject: Risk Factors, organized in nine centers on a national scale, the Operative Unit of Palermo carried out a transverse epidemiological study on a randomized population sample of western Sicily: Casteldaccia, 1984. 1.200 subjects subdivided by age in four decades (20-29; 30-39; 40-49; 50-59 years) and by sex (600 males and 600 females) were enlisted; the participation was 60.25% (No. 723; M = 364; F = 359). Following standardized procedures main cardiovascular risk factors were measured: glycaemia (GOD-PAP), triglycerides (enzymatic), total cholesterol (CHOD-PAP), HDL-cholesterol (MgCl2 dextran sulphate), apolipoproteins A1 and B (R.I.D.), B.M.I. (kg/m2), smoking habits and systolic and diastolic blood pressure (according to WHO manual on Cardiovascular Survey Methods). A questionnaire was used to record the familiar anamnesis, medical history of subjects, term of possible hyperglycaemia, current therapy (use of insulin, oral hypoglycaemic agent, dietetic treatment). The prevalence of diabetes mellitus was 8.16% (59/723): 4.67% (17/364) in males and 11.69% (42/359) in females. The most frequent risk factors associated with diabetes mellitus were; overweight (81%), hypercholesterolemia (49%), hypertriglyceridemia (45%), hypertension (37%) and cigarette smoking (15%).
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PMID:Prevalence of diabetes mellitus and of associated risk factors for atherosclerosis in a randomized population sample of western Sicily. Casteldaccia study. 280 36

While studies have evaluated the accuracy of adult patients and health personnel in reading various glucose oxidase impregnated strips to estimate blood glucose, there are no studies exclusively evaluating the accuracy of children with diabetes reading their own strips as compared to a staff member, and meter to meter variability in reading these strips. We evaluated the accuracy of reading chemstrip bG by children at a summer camp. The children's visual readings of their own strips were compared to the visual reading of a single staff member. A total of 356 Chemstrip bG's were visually read by diabetic children and a single trained staff member at a summer camp for diabetics. The strips were then analyzed by two Accu-Chek bG meters. Intermachine variability was found to be negligible over the entire bG range. For the purposes of this study, we define accurate visual readings as those within +/- 15 percent of the meter reading of a given strip. At low bG values (40-79 mg/dl), accuracy by children and staff is low, with underestimating occurring in 39 percent of staff readings and 57 percent of children's readings. At intermediate bG values (120-239 mg/dl) readings are more accurate, especially when read by the staff, with misreadings occurring in only 16-19 percent of the strips. At high bG values (240-399 mg/dl), accuracy by children is decreased, with underestimation 500 percent more often than staff. We conclude that children are less accurate at reading Chemstrip bG than a trained staff member (51% versus 33% misreading), especially at the upper and lower ranges of bG values when visual readings are least accurate, and the need for therapeutic intervention is the greatest.
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PMID:The accuracy of blood glucose testing by children. 334 27

Paired capillary-venous blood samples were obtained from 418 pregnant women undergoing an oral glucose challenge test (GCT) for the screening of gestational diabetes (GD). The relationship between capillary and plasma glucose concentrations was investigated in order to establish a capillary GCT threshold. Plasma glucose was assayed by the glucose oxidase method and capillary glucose using Reflocheck Glucose strips and a Reflocheck reflectance meter. During GCT the capillary values exceeded plasma glucose values by a mean difference of 10-12 mg/dl fasting and 22-24 mg/dl after 1 h. A high correlation between the glucose values of the two techniques was found, particularly for those at 1 h, with corresponding capillary determinations being 20 mg/dl above plasma values. The sensitivity, specificity and predictive value of the various capillary thresholds investigated in detecting GD corresponded substantially to the accuracy of plasma thresholds 20 mg/dl lower. The receiver operator characteristic curves of the plasma and capillary thresholds were similar in shape and the optimal cut-off point for performing a diagnostic test was set at 135 and 155 mg/dl, respectively. These cut-off values should be reconsidered in the light of the costs and perinatal outcome.
Diabetes Res Clin Pract 1988 May 19
PMID:Capillary glucose determination in the screening of gestational diabetes. 340 33

Glucose dehydrogenase (GDH), one of the recently discovered NAD(P)+-independent 'quinoprotein' class of oxidoreductase enzymes, was purified from Acinetobacter calcoaceticus LMD 79.41 and immobilised on a 1,1'-dimethylferrocene-modified graphite foil electrode. The second-order rate constant (ks) for the transfer of electrons between GDH and ferrocenemonocarboxylic acid (FMCA) in a homogeneous system, determined using direct current (DC) cyclic voltammetry, was found to be 9.4 x 10(6) litres mol-1 s-1. This value of ks for GDH was more than 40 times greater than that for the flavoprotein glucose oxidase (GOD) under identical conditions. Such high catalytic activities were also observed when GDH was immobilised in the presence of an insoluble ferrocene derivative; a biosensor based on GDH was found to produce more than twice the current density of similar GOD-based electrodes. The steady-state current produced by the GDH-based electrode was limited by the enzymic reaction since methods which increased the enzyme loadings elevated the upper limit of glucose detection from 5 mM to 15 mM. The temperature, pH, stability and response characteristics of the GDH-based glucose sensor illustrate its potential usefulness for a variety of practical applications. In particular, the high catalytic activity and oxygen insensitivity of this biosensor make it suitable for in vivo blood glucose monitoring in the management of diabetes.
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PMID:Quinoprotein glucose dehydrogenase and its application in an amperometric glucose sensor. 345 51

Many drugs have been reported to interfere with copper-reduction or glucose oxidase tests used to measure urine glucose. However, only a few drugs or drug classes have been well documented to clinically interfere with these tests. The interfering drugs include ascorbic acid, beta-lactam antibiotics (e.g., cephalosporins and penicillins), levodopa, and salicylates. Several other drugs may also interfere with certain urine glucose tests, but the interactions are poorly documented. These drugs include chloral hydrate, hyaluronidase, nalidixic acid, nitrofurantoin, p-aminosalicylic acid, phenazopyridine, probenecid, and X-ray contrast media. Drugs or their metabolites that are strong reducing substances produce false-positive results by the copper-reduction method and false-negative results by the glucose oxidase method. The beta-lactam antibiotics interfere with copper-reduction tests by producing copper compounds of various colors that confuse interpretation of test results. Tables are provided that summarize the drug interferences discussed.
Diabetes Care
PMID:Review of drug interference with urine glucose tests. 355 7


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