A Study On The Assay And The Use Of 1, 5-anhydro-D-glucitol In Serum

Background& objectiveRecently more and more people have been suffered from diabetes mellitus which isone of the most harmful diseases to people's health and which has drown greatattention. But it is regretful that we can not cure this disease at present. As diabetesmellitus is a chronic disease, it is especially important to have early prevention andearly diagnosis and early treatment. To meet this demand, we develop a study on thedevelopment of kit in the early diagnose of diabetes mellitus. 1,5-Anhydro-D-glucitolis a compound that has been discovered recently in the normal human blood. Becauseof its metabolic stability, it fluctuates narrowly in the blood. It is a short-term markerof glucose and has a good characteristic which fasting blood sugar, fructoamine andglycated hemoglobin don't have. It's valuable in the diagnosis and treatment ofdiabetes mellitus. And it should be spread in clinic.MethodsAs the first part of the research has been finished, the rest will be the later part of thestudy on the development of kit in the early diagnose of diabetes mellitus. Thisresearch is consisted of five parts:1) The Sdudy on Catalysing Specificity of Hexokinase to It's Substrates r, The sameworking enzymatic reagents were used for evaluating the catalyzing specificity to allthe 12 sugar substrates with the same test parameters;2) The Sdudy on Catalysing Specificity of Glucose dehydrogenase to It's Substrates,The same working enzymatic reagents were used for evaluating the catalyzingspecificity to all the 12 sugar substrates with the same test parameters.3) The Sdudy on Catalysing Specificity of Pyranose Oxidase to It's Substrates, Thesame working enzymatic reagents were used for evaluating their catalyzingspecificity to all the 12 sugar substrates, glycerol and ethylene glycol with the same test parameters.4) The Study on the Elimination of Glucose in Samples, hexokinase coupled with6-phosphoglucodehydrogenase was used to assay the concentrations of the residualglucose in reaction solution.5) The setup and clinical use of 1,5-AG assay, the 1,5-AG levels were measured andcompared in 86 normal persons and 134 patients with abnormal glucose enduranceand 106 patients with non-insulin-dependent diabetes mellitus.Results1) When it was 100% of catalyzing effect for glucose, HK/G6PD reagent has nocatalyzing activity for L-sorbose and mannitol; It has little effect for sorbitol (0.01%)and weak effects for D-fructose (0.59%) and D-xylose (0.54%). The effects forD-galactose and 1,5-anhydro-D-glueitol are 1.80% and 1.24% respectively. It has noeffect forα-lactose and little effect for sucrose and cellobiose. But it has an averageeffect 2.55% for maltose.2) When it was 100% of catalyzing effect for glucose, Glucose Dehydrogenasereagent has the highest catalyzing activity for D-galactose(17.13%); The second isD-xylose(8.27%). It has little catalyzing activity for 1,5-anhydro-D-glucitol(1.51%);And it has almost no catalyzing activity for D-fructose L-sorbose and mannitolsorbitol; But in disaccharides its catalyzing specificity was 17.93 % forα-lactose; Ithas very low effects for cellobiose (2.63%) and maltose (1.80%). It has very littleeffect for sucrose(0.39%).3) When it was 100% of catalyzing effect for glucose, the PROD reagent had markedcatalyzing effects for L-sorbose (87.51%) ,D-xylose (83.17%) and1,5-anhydro-D-glucitol (82.32%), and it had a less marked catalyzing effects forD-galactose (40.69%) and little effect for D-fructose, mannitol and sorbitol inmonosaccharides. In disaccharides its catalyzing specificity was 3.19% for maltose and little effect forα-lactose, sucrose and cellobiose. For glycerol and ethyleneglycol with the same concentration, it had a little effect, but the concentration ofglycerol and ethylene glycol used was2.2～3.3% in reagents, so the effect had beenincreased greatly.4) This method could deplete as high as 60mmol/L (10.8g/L) endogenous glucose inspecimens.5) There were significant differences of 1,5-AG levels in 86 normal persons (106.1±59.9) from 134 patients with abnormal glucose endurance (49.4±40.1)and 106patients with non-insulin-dependent diabetes mellitus.(9.6±11.6) with p＜0.001.1,5-AG concentration was markedly decreased in patients and it was decreasemore heavily in patients with abnormal glucose endurance than that in patients withnon-insulin-dependent diabetes mellitus.Conclusions1) Before a new assay is set up the catalyzing specificity of the enzyme for itssubstrates should be evaluated.2) Before a new assay is set up the catalyzing specificity of the enzyme for itssubstrates should be evaluated.3) Before a new assay is set up the catalyzing specificity of the enzyme for itssubstrates should be evaluated.4) Before 1,5-AG assay with PROD was set up, the endogenous glucose in sampleshad to be transformed to other forms that did not interfere 1,5-AG measurement.5) 1,5-AG had important value in evaluating treatment effects in patients withdiabetes, which was worth spreading for clinical application.