Background: Folate is an important substance used for purine and pyrimidine nucleotide synthesis. One measurement of folate that already establishes is using ELISA (Enzyme-linked immunosorbent assay) method. Folate binding protein is a protein that can bind folate, therefore it considered can be used as a tool that can replace antibody dependent ELISA method.Objectives: The aim of this research was to create a method for folate measurement in serum called Enzyme-labeled protein ligand binding assay (ELPLBA) by replacing antibody as used in ELISA method with folate binding protein (FBP) that purified from the whey of milk.Methods: The method is tested using 20 serum samples and compared to ELISA. Folate binding protein was purified from bovine's milk using ammonium sulfate up to 90% saturated, DEAE-cellulose anion exchange chromatography and affinity chromatography. SDS-PAGE and western blot were used to establish the protein band of FBP that has molecular weight of ~25-35 kDa. ELPLBA was arranged with stationary phase using aminohexyl-agarose, and folic acid linked on it using carbodiimide.Results: The result show there was no significant difference of folate concentration between ELPLBA (14.804 ± 2.795) and ELISA method (13.859 ± 3.638), p = 0.363.Conclusion: ELPLBA method show similarity for determination of folate in serum which was the same as standard folate measurement (ELISA).

Background: High altitude can cause hypobaric hypoxia (HH), resulted from the lower barometric pressure and hence partial pressure of oxygen. Hypoxia can lead to a lot of deleterious molecular and cellular changes, such as generation of free radicals or reactive oxygen species (ROS). Increasing of ROS can cause oxidative stress if the antioxidant enzyme does not increase simultaneously. Oxidative damage in brain has toxic effect on cognitive functions.Objective: In this study, we investigate effect of acute intermittent HH on oxidative stress and antioxidant enzyme activity in rat brain.Method: Wistar rats divided into 5 groups, consisting control group and four experimental groups which treated to HH. Rats were exposed to simulated HH equivalent to 35.000 feet in hypobaric chamber for 1 minute, repeated once a week.Results: Level of malondialdehyde and carbonyl in rat brain under acute HH increased at HH exposure (group I) compare to control group. These levels decreased afterward at intermittent HH exposure (group II-IV). Specific activity of superoxide dismutase (SOD) shows increasing level at intermittent HH exposure, especially group IV was increasing of SOD level significantly. The increasing pattern of specific activity of catalase was inversely from SOD pattern, but it still has higher activity in intermittent HH compare to control group.Conclusion: Brain tissue seems to be able to perform an adequate adaptive response to hypobaric hypoxia after the training, shown by its significantly decreased MDA and carbonyl level and also increased specific activity of SOD and catalase.