Development of a plasma maltose assay method as a screening test for upper gastrointestinal disorders.

Background And Objective: The disaccharide loading test is a method to assess gastric mucosal damage. Since Trelan-G75, which is used for the sugar tolerance test, contains disaccharide maltose, if maltose is detected at a high sensitivity in the sample blood used in the sugar tolerance test, screening for upper gastrointestinal mucosal damage can be made simultaneously with the sugar tolerance test for the diagnosis of diabetes.

Methods: Glucose-6-phosphate is generated by treating maltose with maltose phosphorylase, β-phosphoglucomutase, and glucose-1,6-bisphosphate.

Pyrophosphate detection method using 5-Br-PAPS to detect nucleic acid amplification - Application to LAMP method.

Genetic testing has been increasingly used in several fields. In many applications, nucleic acid amplification technology is required. However, current methods to detect nucleic acid amplification require expensive reagents and special equipment or exhibit limited sensitivity, which hinders their use.

Development of a protein assay with copper chelator chromeazurol B, based on the biuret reaction.

This study aimed to provide a novel and highly sensitive protein assay based on the biuret reaction and using chromeazurol B, a metal chelate compound. The method consists of two reagents and an automated analyzer. First, a complex of copper and protein (biuret reaction) is formed.

New colorimetric method with bromocresol purple for estimating the redox state of human serum albumin.

Oxidative damage results in protein modification and is observed in many diseases, such as heart failure and renal insufficiency. Human serum albumin is an index of oxidative change and is conventionally measured using high-performance liquid chromatography (HPLC). Although this method is more sensitive than the colorimetric method, it is time-consuming for clinical practice and the sera must be stored at -80°C before analysis.

Characterization and application of a novel nicotinamide mononucleotide adenylyltransferase from Thermus thermophilus HB8.

Herein, we describe a novel enzymatic cycling method to measure nicotinamide mononucleotide (NMN) or nicotinic acid mononucleotide (NaMN), which are precursors of NAD biosynthesis. A gene encoding an NMN adenylyltransferase (NMNAT, EC 2.7.

Development of a simple indocyanine green measurement method using an automated biochemical analyser.

Background The indocyanine green retention rate is important for assessing the severity of liver disorders. In the conventional method, blood needs to be collected twice. In the present study, we developed an automated indocyanine green method that does not require blood sampling before intravenous indocyanine green injections and is applicable to an automated biochemical analyser.

Preliminary evaluation of an improved enzymatic assay method for measuring potassium concentrations in serum.

Background: K(+) has important physiological functions. K(+) concentrations in serum are generally determined using ion-selective electrodes (ISEs), though measurement using reagents in aqueous medium is also useful.

Methods: K(+) concentrations were measured using recombinant inosine 5'-monophosphate dehydrogenase (IMPDH), which was activated only by K(+) and NH4(+).

Highly sensitive reversed-phase high-performance liquid chromatography assay for the detection of Tamm-Horsfall protein in human urine.

Background: Tamm-Horsfall protein (also known as uromodulin) is the most abundant urinary protein in healthy individuals. Since initially characterized by Tamm and Horsfall, the amount of urinary excretion and structural mutations of Tamm-Horsfall protein is associated with kidney diseases. However, currently available assays for Tamm-Horsfall protein, which are mainly enzyme-linked immunosorbent assay-based, suffer from poor reproducibility and might give false negative results.

Development of an assay of seven biochemical items, HbA1c, and hematocrit using a small amount of blood collected from the fingertip.

Background: Lifestyle-related diseases in Japan account for 30% of the entire medical expenditure of the country and cause 60% of all deaths. For the prevention of lifestyle-related diseases, medical examination by laboratory tests on metabolic syndrome is important.

Methods: To undertake examination by collection of blood from a fingertip, we developed the "Well Kit".

Enzymatic assay of phosphatidylethanolamine in serum using amine oxidase from Arthrobacter sp.

Background: In human serum, as for phospholipids not containing choline, phosphatidylethanolamine (PE) exists approximately 5% in a whole phospholipid. PE is well known as one of the main components of biological membranes, and also plays important roles that contribute to apoptosis and cell signaling. However, it could not measure PE with other phospholipids due to a lack of choline in them.

Effect of ambient light variations on luminance ratio of CRT monitor and image contrast in ultrasonography.

Variation in the luminance ratio of a cathode ray tube(CRT)monitor and the ultrasonographic images at different levels of ambient light(0-150 lux)was investigated to obtain optimum ambient light in the ultrasonography suite. The maximum and minimum luminances of test patterns and ultrasonographic images were measured after three technicians independently optimized the brightness and contrast of the CRT monitor and ultrasonographic images at different levels of ambient light. Furthermore, the luminance ratio was calculated from the maximum luminance divided by the minimum luminance.

Development of a new measurement method for serum calcium with chlorophosphonazo-III.

Background: Although serum calcium has been measured using the o-cresolphthalein complexone (oCPC) method in the clinical laboratory, this method still has some problems regarding linearity and reagent stability. We developed a new measurement procedure using chlorophosphonazo-III (CPZ-III: 2,7-bis (4-chloro-2-phosphonophenylazo) -1,8- dihydroxy-3, 6-naphthalenedisulphonic acid, disodium salt) as a chelator with an acid medium for serum calcium measurement. The present method showed better linearity and reagent stability compared with the oCPC method.

Enzymatic characterization of an amine oxidase from Arthrobacter sp. used to measure phosphatidylethanolamine.

Ethanolamine oxidase was screened with the aim of using it to establish a novel enzymatic phosphatidylethanolamine assay. Ethanolamine oxidase activity was detected in the crude extract of Arthrobacter sp., and the enzyme was purified more than 15-fold in three steps with a 54% yield.

[Establishment of mail medical examination system using immediate plasma separating device by the self-collection blood--the method of dilution ratio calculation by using Internal standard for the sample with different amount of collecting blood].

A method of calibrating unquantified samples was developed in order to conduct tests from approximately 65 microl or less of self-collected whole blood from the finger. In this method, the dilution ratio is estimated by absorption analysis of an internal standard substance in the blood dilution buffer. Good results for replication of the dilution ratio were obtained, with a CV value of 0.

[Analysis of proteins in urinary tract stones and urine of urolithic patients].

In order to investigate the mechanism of urinary tract stone formation, we analyzed protein components in urine and the stone. Urinary proteins of healthy subjects and urolithic patients as well as protein components urinary tract stone of the urolithic patients were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Electrophoretic patterns of urinary proteins of the patients differed from those of healthy subjects after separating protein patterns into those larger than 66kDa or smaller than 30kDa.