Fluorometry of Citrate in Serum, with Use of Citrate (pro-3S)-Lyase

1975 ◽  
Vol 21 (6) ◽  
pp. 730-734 ◽  
Author(s):  
Arthur J Tomisek ◽  
Edward M Winkler ◽  
Samuel Natelson
Keyword(s):  
Glucose Tolerance ◽  
Tolerance Test ◽  
Initial Values ◽  
Endogenous Insulin ◽  
Significant Difference ◽  
Human Sera ◽  
Glucose Tolerance Tests ◽  
Lactate Dehydrogenases ◽  
Range Of Values

Abstract We describe a procedure for enzymatic assay of citrate in human serum. The citrate is degraded to acetate and oxaloacetate with citrate oxaloacetate-lyase (pro-3S-CH2 · COO- → acetate) (EC 4.1.3.6). Some oxaloacetate loses CO2 to form pyruvate. Addition of malate and lactate dehydrogenases (EC 1.1.1.37 and 1.1.1.27) permits determination of the oxaloacetate and pyruvate generated, and thus of the citrate concentration. The decrease in NADH concentration is measured fluorometrically. Results obtained for 30 consecutive human sera by this procedure were compared to the procedure in which the citrate is converted to pentabromoacetone. There was no statistically significant difference in values obtained by the two procedures. The range of values (mean ± 2 SD) found for sera from 25 blood donors by this procedure was 12.8-27.2 mg/liter (mean, 19.0 mg/ liter). Serum citrate as measured by both procedures during a glucose tolerance test was decreased from initial values under the influence of administered glucose (and endogenous insulin). Insulin concentrations were also measured during these glucose-tolerance tests. Citrate concentrations remain subnormal after the glucose and insulin concentrations return to their initial values. This accords with published reports.

IMMUNOLOGICAL REACTIVITY OF INSULIN IN HUMAN SERUM

1966 ◽  
Vol 53 (4) ◽  
pp. 673-680 ◽  
Author(s):  
Torsten Deckert ◽  
Kai R. Jorgensen
Keyword(s):  
Normal Subjects ◽  
The Other ◽  
Human Pancreas ◽  
Porcine Pancreas ◽  
Crystalline Insulin ◽  
Endogenous Insulin ◽  
Significant Difference ◽  
Human Sera ◽  
Normal Human ◽  
The One

ABSTRACT The purpose of this study was to investigate whether a difference could be demonstrated between crystalline insulin extracted from normal human pancreas, and crystalline insulin extracted from bovine and porcine pancreas. Using Hales & Randle's (1963) immunoassay no immunological differences could be demonstrated between human and pig insulin. On the other hand, a significant difference was found, between pig and ox insulin. An attempt was also made to determine whether an immunological difference could be demonstrated between crystalline pig insulin and crystalline human insulin from non diabetic subjects on the one hand and endogenous, circulating insulin from normal subjects, obese subjects and diabetic subjects on the other. No such difference was found. From these experiments it is concluded that endogenous insulin in normal, obese and diabetic human sera is immunologically identical with human, crystalline insulin from non diabetic subjects and crystalline pig insulin.

scholarly journals Beneficial Effect of Diazoxide in Obese Hyperinsulinemic Adults1

1998 ◽  
Vol 83 (6) ◽  
pp. 1911-1915 ◽  
Author(s):  
Ramin Alemzadeh ◽  
Gina Langley ◽  
Lori Upchurch ◽  
Pam Smith ◽  
Alfred E. Slonim
Keyword(s):  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Body Fat ◽  
Therapeutic Potential ◽  
Controlled Trial ◽  
Insulin Response ◽  
Tolerance Test ◽  
Fat Free Mass ◽  
Zucker Rats ◽  
Significant Difference

Hyperinsulinemia, insulin resistance, and increased adipose tissue are hallmarks of the obesity state in both humans and experimental animals. The role of hyperinsulinemia as a possible preceding event in the development of obesity has been proposed. We previously demonstrated that administration of diazoxide (DZ), an inhibitor of insulin secretion, to obese hyperinsulinemic Zucker rats resulted in less weight gain, enhanced insulin sensitivity, and improved glucose tolerance. Assuming that hyperinsulinemia plays a major role in the development of human obesity, then its reversal should have therapeutic potential. To test this hypothesis, we conducted a randomized placebo-controlled trial in 24 hyperinsulinemic adults [body mass index (BMI) > 30 kg/m2]. All subjects were placed on a low-calorie (1260 for females and 1570 for males) Optifast (Sandoz, Minneapolis, MN) diet. After an initial 1-week lead-in period, 12 subjects (mean ± se for age and BMI, 31 ± 1 and 40 ± 2, respectively) received DZ (2 mg/kg BW·day; maximum, 200 mg/day, divided into 3 doses) for 8 weeks; and 12 subjects (mean± se for age and BMI, 28 ± 1 and 43 ± 1, respectively) received placebo. Compared with the placebo group, DZ subjects had greater weight loss (9.5 ± 0.69% vs. 4.6 ± 0.61%, P < 0.001), greater decrease in body fat (P < 0.01), greater increase in fat-free mass to body fat ratio (P < 0.01), and greater attenuation of acute insulin response to glucose (P < 0.01). However, there was no significant difference in insulin sensitivity and glucose effectiveness, as determined by the insulin-modified iv glucose tolerance test (Bergman’s minimal model) and no significant difference in glycohemoglobin values. Conclusion: 8 weeks treatment with DZ had a significant antiobesity effect in hyperinsulinemic obese adults without inducing hyperglycemia.

GLUCOSE TOLERANCE TESTS MODELING & PATIENT-SIMULATION FOR DIAGNOSIS

2001 ◽  
Vol 01 (02) ◽  
pp. 193-223 ◽  
Author(s):  
SARMA S. DITTAKAVI ◽  
DHANJOO N. GHISTA
Keyword(s):  
Blood Glucose ◽  
Glucose Tolerance ◽  
Oral Glucose Tolerance Test ◽  
Glucose Tolerance Test ◽  
Patient Simulation ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Model Parameters ◽  
Oral Glucose Tolerance ◽  
Glucose Tolerance Tests

Diabetes mellitus is a heterogeneous clinical syndrome characterized by hyperglycemia and long-term specific complications: retinopathy, neuropathy, nephropathy, and cardiomyopathy. Automatic neuropathy leads to visceral denervation producing a variety of clinical abnormalities: cardiac and respiratory dysrythaemias, gastrointestinal motility disorders, urinary bladder dysfunction and impotence. Diabetes mellitus is a leading cause of blindness; renal failure and limb amputation all over the world. The need to detect diabetic risk factors and treat organ disorders and complications associated with diabetes provides the impetus for us to develop the technology for assessment of diabetes, its etiology and severity, as well as for assessing the efficacy of pharmacological therapy. This paper concerns: (i) modelling of blood-glucose regulation and tolerance-testing, (ii) demonstrating patient-simulation of the blood-glucose regulatory models, by means of which the model parameters can be evaluated and related to physiological parameters, and (iii) elucidating how the glucose-regulatory system model's pole-zero representation and the blood glucose-insulin transfer-function can explain the blood glucose response data in intravenous and oral glucose tolerance tests. An easy-to-implement simple clinical-application method is developed to simulate the response of the blood-glucose regulatory model in diabetic patients during intravenous glucose tolerance test and to estimate the model parameters, which can then enable differential diagnosis of diabetes and its severity as well as in early detection of risk-to-diabetes. In the oral glucose-tolerance test, the role of the gut is to facilitate transport of glucose across the intestinal wall. The Michaelis-Menten equation, describing this enzyme-catalyzed reaction rate, can be employed to conclude that the intestinal glucose absorption rate into the blood-compartment from the gut during the oral glucose-tolerance test is constant, almost resembling a rectangular pulse Nevertheless, we have formulated a new rate-control model to simulate the oral glucose-tolerance test data, by means of the response-function of a second-order system of a single-compartment (consisting of the gut and the blood-glucose pool), with the oral glucose-bolus as the impulse-input. We have also demonstrated application of this rate-control model to patients undergoing oral glucose-tolerance test, to evaluate the model parameters. By categorizing the ranges of these parameters for normals and diabetics (varying from mild to severe), we can reliably apply this model and procedure clinically.

Measurement of hemoglobin A1c by a new liquid-chromatographic assay: methodology, clinical utility, and relation to glucose tolerance evaluated.

1986 ◽  
Vol 32 (10) ◽  
pp. 1867-1872 ◽  
Author(s):  
J O Jeppsson ◽  
P Jerntorp ◽  
G Sundkvist ◽  
H Englund ◽  
V Nylund
Keyword(s):  
Glucose Tolerance ◽  
Hemoglobin A1c ◽  
Cation Exchanger ◽  
Reference Interval ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Hb A1c ◽  
Single Column ◽  
Glucose Tolerance Tests ◽  
Liquid Chromatographic

Abstract A chromatographic method for determining glycated hemoglobin (Hb A1c) by use of a new monodisperse cation-exchanger has been investigated. Hb A1c was separated from other "minor hemoglobins": Hb F, Hb A3 (the glutathione adduct), and the acetaldehyde adduct in alcoholics. The method was fully automated and a single column could be used for more than 1000 runs. The normal reference interval was 4.0-5.2%; the interval for diabetic outpatients was 5.6-12.4%. Within-run and the between-run CVs were less than 0.9% and 1.7%, respectively. Carbamylation in uremic patients who were undergoing hemodialysis increased the proportion of Hb A1c to 1%. Hb A1c results were compared with results from glucose tolerance tests. In our study, Hb A1c less than 5.5% excluded diabetes: subjects with Hb A1c greater than 6.2% showed diabetes. If blood sampled during fasting had been screened with determinations of glucose and Hb A1c, only 20% of referred subjects would have needed an oral glucose tolerance test for diagnosis of diabetes.

scholarly journals Continuous Glucose Monitoring System in Acromegalic Patients: Possible Role in the Assessment of Glycemia Control

2020 ◽  
pp. 193229682094988
Author(s):  
Valeria Mercuri ◽  
Tania D’Amico ◽  
Denise Costa ◽  
Corrado De Vito ◽  
Luca D’Angelo ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Monitoring System ◽  
Continuous Glucose Monitoring ◽  
Somatostatin Analogs ◽  
Glucose Monitoring ◽  
Tolerance Test ◽  
Continuous Glucose Monitoring System ◽  
Oral Glucose ◽  
Time Curve ◽  
Significant Difference

Background: Acromegaly is characterized by an insulin resistance condition. There is a significant difference between the different types of therapy in relation to the glycometabolic framework. The blinded continuous glucose monitoring system (CGMS), throughout a period of maximum 6 days for a total of 288 glycemic registrations per day, identifies glycemic excursions and could constitute a valid device to understand the 24-hour glycemic profiles. Aim of the study: To compare the oral glucose tolerance test (OGTT) and CGMS methods in acromegalic patients to evaluate their glycemic profiles, in relation to different treatments for acromegaly. Methods: Thirty-five acromegalic patients were divided into 18 somatostatin analogs (SSA), 9 pegvisomant, and 8 successfully surgically treated. A 72-hour CGM was performed and, immediately after, an OGTT. Results: Results obtained from OGTT: 11/35 impaired fasting glucose, 6/35 impaired glucose tolerance, and 4/35 diabetes mellitus. A positive significant correlation was demonstrated between the OGTT peak and CGM peak in all of the patients, CGM peak of patients treated with SSA and those surgically treated, OGTT average and CGM area under concentration–time curve (AUC) for hyperglycemia of patients treated with SSA and those surgically treated, and CGM AUC for hyperglycemia of patients treated with SSA and those surgically treated. Conclusions: Our results show a significantly higher response in terms of mean and peak OGTT in patients treated with SSA, both compared to the CGM study, and compared to the group of patients receiving pegvisomant. The CGM system could represent an instrument for the evaluation of the glycemic trend of acromegalic patients.

Reproducibility of a glucose tolerance test

1962 ◽  
Vol 17 (1) ◽  
pp. 119-122 ◽  
Author(s):  
J. D. Acland ◽  
H. Clayton ◽  
B. Mitchell
Keyword(s):  
Glucose Tolerance ◽  
Statistical Method ◽  
Glucose Tolerance Test ◽  
Tolerance Test ◽  
Physiological Mechanisms ◽  
Glucose Test ◽  
Glucose Tolerance Tests ◽  
Experimental Subjects ◽  
Normal Men

A statistical method is described for testing the significance of changes in the glucose tolerance of experimental subjects in different conditions. Statistically significant changes in glucose tolerance from day to day were observed in seven normal men who underwent glucose tolerance tests on 3 successive days. No statistically significant changes in glucose tolerance were found on the 2nd day after a glucose tolerance test in further experiments using five normal men. Possible physiological mechanisms by which the performance of a glucose test could cause alterations in glucose tolerance are discussed. Submitted on December 19, 1960

scholarly journals ORAL GLUCOSE TOLERANCE TEST AND DETERMINATION OF SERUM FRUCTOSAMINE LEVEL IN BEAGLE DOGS

2004 ◽  
Vol 29 (1) ◽  
pp. 33-36 ◽  
Author(s):  
Dai WATANABE ◽  
Hiromi NAKARA ◽  
Keisuke AKAGI ◽  
Toshiya ISHII ◽  
Hiroyasu MIZUGUCHI ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Oral Glucose Tolerance Test ◽  
Glucose Tolerance Test ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Beagle Dogs ◽  
Serum Fructosamine
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