A novel assay for serum creatinine using a creatine kinase cycling reaction

For assaying serum creatinine, the enzymatic method is regarded as accurate. However, reliable measurement of low levels is problematic. We have developed a new method that utilizes an enzymatic cycling reaction involving creatine kinase (CK) in the presence of excess ATP and IDP and implicated the application to serum creatinine assay incorporating with creatininase. Here, we evaluated applying the CK cycling method to a serum creatinine assay. In this study, we focused on assessing whether an accurate measurement could be achieved, especially in the reference interval and the lower concentration range. The effective sensitivity of the assay using 30 U/mL CK was approximately 4-fold greater than that of a commercial reagent. Under these conditions, .19 mg/dL of creatinine was accurately detected. The correlation coefficient of the comparison study with an existing commercial reagent was .995. Moreover, the effect of the increased signal intensity on accuracy and precision was assured.

THE ROLE OF VASCULAR HOMEOSTASIS IN WOMEN WITH INFERTILITY TREATED WITH ASSISTED REPRODUCTIVE TECHNOLOGIES AND WITH CONCOMITANT INTRAHEPATIC CHOLESTASIS

Intrahepatic cholestasis of pregnancy (idiopathic jaundice of pregnancy, recurrent familial jaundice of pregnancy) is a benign familial disease manifesting itself in the gestational period in itching and (or) jaundice. As a rule, the disease is observed in the 3rd trimester of pregnancy, that is in the 28th-30th week, and may disappear by itself a few days after labor and recur during future pregnancies.The aim of this research is to study the role and factors of vascular homeostasis regulation in women with infertility treated with assisted reproductive technologies (ART) and with concomitant intrahepatic cholestasis. Intrahepatic cholestasis is characterized by the damage of endothelial cells of hepatic sinusoids, changes in the intrahepatic hemodynamics, increased production of cytokines and free radicals. The processes of angiogenesis in the liver are also closely connected with the functional capacity of endothelium. The L-arginine level in blood was measured using the photometric method based. The homocysteine level was measured by the enzymatic cycling method. To measure the level of placental growth factor (PGF) in blood plasma samples, we used the immunochemical method.The research has found especially severe complications in the course of pregnancy after ART in those women with intrahepatic cholestasis whose placentas developed under the conditions of endothelial dysfunction from the very beginning of pregnancy.So, these factors may be early prognostic markers of severe obstetrical and perinatal disorders in women with induced pregnancy and hepatobiliary disorders.

Development of an enzyme cycling method by a purine nucleoside phosphorylase for assaying inorganic phosphate

We have developed a novel enzymatic cycling method that uses purine nucleoside phosphorylase (PNP) (EC 2.4.2.1) fromBacillussp. to measure inorganic phosphate.