Objective To develop an improved enzymatic method for assaying creatinine in serum and urine. Methods Cratinine iminhydrolase catalyzes the conversion of creatinine to N-methylhydantoin and ammonia,the later combines with 2-oxoglutarate and NADPH in the presence of glutamate dehydrogenase.Before beginning the reaction sequence,endogenous ammonia is removed by an “ammonia scavenger system”that involves the same auxiliary reaction.The NADPH and 2-Oxoglutarate consumed are restored through a reaction catalyzed by isocitrate dehydrogenase.The activity of this strictly magnesium-dependent enzyme is completely blocked by magnesium-complexing reagent that acts promptly whenever the reaction has started with creatinine iminohydrolase as startor.The reaction is monitored kinetically by measuring the NADPH decrease via its absorbance at 340nm.Results The method affords a simple,rapid,and sensitive assay with good precision and extended linearity.Test results compare closely with the HPLC precedure.The proposed method is not subject to interference from several metablites or from the drugs used commonly in clinics.Conclusion The method is easily automated and is suitable for routine work in clinical laboratories.

Objective To investigate the prevalence of dyslipidemia,hyperglycemia,hypertension and metabolic syndrome(MS)and compare the prevalence rate of dysilipidemia obtained in this study with the previous study during 1984--1986.Methods A total of 16 344 adults in Beijing who attended for the medical examinations were recruited in the study.Subjects were asked to complete questionnaires regarding personal health,lifestyle and family health history.The physical examination emphasized measurement of height,weight and blood pressure.Blood samples were collected after an overnight fast and subjected to serum glucose,TC,HDL-C,LDL-C and TG measurements.MS was diagnosed according to Diabetes Society of Chinese Medical Association(CDS)criteria.Results Dyslipidemia occurred in 36.9%(6 034)of subjects.948 hyperglycaemia cases were found.The prevalence rate of high blood glucose was 5.8%. Hypertension occurred in 17.1% of subjects.Obesity/Overweight occurred in 5 252 subjects with the prevalence rate of 32.1%.On the basis of the diagnostic criteria for MS in China.MS occurred in 12.2% of subjects(14.2% for males and 10.0% for females).In both genders,the rate increased along with the increment of age.65.5% participants had at least one of the metabolic disorders.The prevalence of hypercholesterolemia,hypertriglyceridemia,and abnormally low HDL-C were higher than previous analysis during 1984-1986 in all age groups.Conclusions The prevalence of MS in this large occupational population in Beijing was quite high. The prevalence of hypeflipemia had increased considerably over the past 20 years.Balanced nutrition and reasonable consumption should be undertaken to modify these situations.

74 years were associated with increased cardiac events too(HR = 5.40,95%CI:2.16~11.52,P=0.0002).NYHA classification, LVEF, cTnT?cTnI and CK-MB were not independently predictive of cardiac events.Conclusions Measurement of NT-proBNP in patients with CHF can help to identify patients at higher risk for cardiac events .

Objective To investigate the influence of renal function on serum NT-proBNP in the diagnosis of chronic heart failure by observing the relationship between eGFR and NT-proBNP in serum and comparing cutoff values of NT-proBNP in different eGFR levels.Methods 297 elderly participants were enrolled in the study, including 106 inpatients with heart failure and 191 healthy controls in the corresponding period.The concentration of NT-proBNP was determined by an automated electrochemiluminescence immunoassay on Roche Elecsys 2010.Estimated glomerular filtration rate (eGFR) was calculated using the Levey-modified Modification of Diet in Renal Disease formula. The diagnosis of clinical physician was considered to be the golden standard for heart failure.Results Serum NT-proBNP levels were significantly higher in subjects with renal dysfunction compared with those with normal renal function for heart failure patients [829.1 (202.4 ~ 3725.5) ng/L vs. 227.2 (111.1 ~ 964.2) ng/L, P

Objective To investigate the level of human cytomegalovirus(HCMV)specific CD8+ T lymphoeytes in peripheral blood and the immune reaponae of HCMV reactivation after kidney transplantation.Methods Thirty-eight HCMV seropesitive HLA-A*0201 kidney transplant recipients(9 with HCMV infection and 29 without HCMV infection)and 54 healthy individuals were enrolled.The levels of total HCMV specific CD8+ T cells were measured using HLA-A2 pentamer folded with HCMV-peptide NLVPMVATV.The levels of IFN-γ secreting CD8+ T cells were measured by intracelluhr IEN-γ staining pulsed with the same peptide.Results The median levels of pentamer stained CD8+ T cells were 1.19%(0-19.42%),1.20%(0-18.40%)and 3.2%(0.51%-18.90%)in healthy group,negative HCMV group and positive HCMV group(H=5.34,P＞0.05),respectively.The median levels of IFN-γ secreting CD8+ T cells were 0.72%(0-0.70%),0.47%(0-5.61%)and 0.67%(0.07%-4.00%),respectively(H=0.58,P＞0.05).However,the mean proportions of IFN-γ secreting pentamer stained T cells relative to total HCMV specifc CIL were(60.18±19.16)%,(39.19±17.22)% and(20.02±13.26)%,respectively.There were significant differences among the groups(P＜0.01).Condusiorm There was no significant difference of levels of HCMV specific CD8+ T lymphocytes in peripheral blood between the kidney transplant recipients and healthy individuals.However,the proportion of HCMV-specific IFN-γ producing CD8+ T cells in pentamer stained cells was reduced in the kidney transplant recipients especially in those with active HCMV infection,which may contribute to the inability to control HCMV reactivation.

Objective This study was designed to estimate the value of Cystatin C, compared to routine marker (Scr、Ccr), as the screening marker for reduced GFR in type 2 diabetes patient. Methods The study was performed on 51 type 2 diabetic patients, and GFR was estimated by the plasma clearance of ~ 99m Tc-DTPA. Sensitivity and specificity for the diagnosis of renal impairment were calculated by receiver operating characteristic (ROC) curves for above three parameters.Results Correlation coefficients with ~ 99m Tc-DTPA were-0.744 for serum Cystatin C,-0.658 for serum creatinine, 0.625 for creatinine clearance (all P

Objective To construct a prokaryotic expression system for human creatine kinase(CK) MM isozyme,purify the recombinant protein of CK expressed in Eschericheia coli(E.coli) and examine the stability of the recombinant protein for its application in CK measurement system as the quality control.Methods Total RNA of extracted from fetal cardiac muscle was reversetranscripted and cDNA encoding human CK was amplified which was inserted into pET-15b plasmid vector.The recombinant plasmid was transfered into E.coli BL21(DE3) and induced by isopropyl-?-D-thiogalactopyranoside(IPTG).Recombinant CK-MM was separated from bacterial proteins by affinity chromatography on a Ni2+-Sepharose column.The activity of the recombinant enzyme was observed in different matrixes.Results The enzymatic activity of the crude extracts of CK-MM was up to 280,000U/L.After one step affinity chromatography,the fusion protein showed a single band in SDS-PAGE gel.The purified protein was stable and the enzymatic activity remained unchanged for a month in the matrix containing bovine serum albumin,EDTA and 1,4-Dithiothreitol(DTT).Conclusion The recombinant CK-MM showed key properties of the native creatine kinase isozyme and may be used as control and calibrator for determination of serum CK-MM.