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Biomedical subjects

Y Kayamori

Publications and source records attributed to Y Kayamori.

At least 19 recordsLinked to original sources
PubMed2001

Propofol as a continuous infusion during cardiopulmonary bypass does not affect changes in serum free fatty acids.

Perioperative myocardial infarction or ischaemia is a potential consequence of cardiac surgery and elevated free fatty acids can increase the severity of myocardial ischaemic damage. We investigated perioperative changes in serum free fatty acids, and other serum lipids, as a consequence of using propofol infusions for cardiac surgery during cardiopulmonary bypass. Twenty-five patients undergoing elective coronary artery bypass grafting were allocated to two groups. One group of 12 patients was given a continuous infusion of propofol and the other group of nine patients received intermittent boluses of midazolam as a hypnotic agent. Serum lipid concentrations were measured at four periods perioperatively. Changes in free fatty acid concentrations were similar between the two groups. Lipid concentrations related to triglyceride in the propofol group decreased on one occasion but subsequently returned to control value. On the other hand, such values in the midazolam group remained lower than control values. Propofol is not a contraindication as an anaesthetic for cardiac surgery in respect of concern regarding the effects of free fatty acids.

Aged↗
PubMed2000

Nonenzymatic elimination of ascorbic acid in clinical samples.

OBJECTIVES: Ascorbic acid interferes significantly in the oxidative reaction of chromogenic reagents by peroxidase and hydrogen peroxide. Currently, ascorbate oxidase is commonly utilized for eliminating the interference of ascorbic acid in the oxidative colorimetric reaction. This enzyme, however, displays several disadvantages, such as high cost, variation from lot to lot, and low stability. We applied a series of commercially available and stable radicals (ascorbic acid quenchers [AAQs]) for nonenzymatic quenching of ascorbic acid in the uricase-based uric acid determination in serum and urine. DESIGN AND METHODS: In order to evaluate the quenching activity of AAQs, a commercially available uric acid detection kit was used. TBA-80FR.NEO biochemical analyzer was utilized for the assay. RESULTS: 4-Hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy free radical (AAQ-2) was the most effective ascorbic acid quencher among the four stable radicals, and the uric acid assay suffered no interference by AAQ-2. The ascorbic acid quenching ability of 2 mmol/L of AAQ-2 in reagent solution (reagent-I) was > or = 2 U/ml ascorbate oxidase in reagent solution. CONCLUSIONS: AAQ-2 was proven to be a suitable quencher of ascorbic acid in clinical samples.

Ascorbate Oxidase↗
PubMed1999

Endpoint colorimetric method for assaying total cholesterol in serum with cholesterol dehydrogenase.

BACKGROUND: Various methods are available to measure serum cholesterol concentrations. Of these, the cholesterol ester hydrolase (CEH)-cholesterol oxidase-peroxidase chromogenic method is widely used. However, this method has the disadvantage of interference by reducing substances. We developed and evaluated an endpoint assay for serum cholesterol, based on a CEH-cholesterol dehydrogenase (CDH)-ultraviolet method. METHODS: Cholesterol esters are first hydrolyzed to free cholesterol by CEH. The free cholesterol is then reduced by CDH to cholest-4-ene-3-one with the simultaneous production of beta-NADH from beta-NAD(+). At equilibrium, the CDH reaction gives incomplete conversion of cholesterol to cholest-4-ene-3-one. To overcome this disadvantage, we added hydrazine monohydrate to the reaction mixture to remove cholest-4-ene-3-one, which allowed the reaction to proceed to completion and gave stoichiometric production of beta-NADH from the reaction of beta-NAD(+) with cholesterol. RESULTS: We tested whether the amount of cholesterol added was equivalent to the absorbance change of NADH at 340 nm with six aqueous samples. Recoveries were 97.1-100.3%. The reaction was linear up to 20.28 mmol/L. The mean within-day (n = 20) and between-day (n = 10) imprecision (CV) was 0. 29-0.43% and 0.22-0.61%, respectively. No interference by bilirubin, hemoglobin, ascorbic acid, and other reducing agents was observed. The equation obtained in comparison with the modified Abell-Levy-Brodie-Kendall method was: y = 0.992x - 0.0058 mmol/L; r = 0.997; S(y|x) = 0.117 mmol/L; n = 50. CONCLUSION: This method is an accurate, reliable method for serum cholesterol analysis and is amenable to automation.

Cholesterol↗
PubMed1998

[Sampling and quality assurance].

For the efficient operation of clinical laboratories, automated biochemical analyzers have been improved. Large rapidly analyzing and multichannel analyzers, and small or mid-sized multiple component analyzers are now commercially available and widely use. Such apparatus might require only a small amount of specimen and reagent to assay one analyte. Performance has been increased annually. In this report, we discuss whether this performance, sampling of specimen, sampling of reagent, and mixing effect of reaction mixture or diluted specimen affect the accuracy and precision of measurements.

Autoanalysis↗
PubMed1997

Enzymatic method for assaying uric acid in serum with a new tetrazolium salt produces water-soluble formazan dye.

OBJECTIVES: To apply an enzymatic method for assaying uric acid in serum based on the uricase (EC 1.7.3.3)-catalase (EC 1.11.1.6)-formaldehyde dehydrogenase (FADH, EC 1.2.1.46) coupled with the new tetrazolium salt producing a water-soluble formazan dye as an indicator system. Unlike the traditional tetrazolium salts, e.g., iodonitrotetrazolium (INT) and nitrotetrazolium blue (NTB), the corresponding formazan dye produced did not absorb to the test tube and the reaction cells of the analyzer. Moreover, this formazan dye had a higher water solubility and more sensitivity. DESIGN AND METHODS: A two electron reduction of tetrazolium salt with NADH, produced by the uricase-catalase-FADH reaction, was mediated by an electron carrier, 1-methoxy PMS. The generation of formazan, monitored at 440 nm, was proportional to the concentration of uric acid in serum. The sensitivity of this method was about 1.5 times that of the peroxidase-TOOS [N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine] method. The assay was evaluated with TBA-80FR.NEO biochemical analyzer. The average within-run and between-day imprecision (CV) were 0.75-2.44% and 3.20-3.33%, respectively. RESULTS: Results of the proposed method (y) correlated well with those determined by the conventional chromogen method (x): y = 0.970 x - 0.018 mmol/L (Sy l x = 0.019 mmol/L, r = 0.993, n = 67). CONCLUSIONS: We also present data showing that the method is rapid, relatively free of interference, and amenable to automation.

Coloring Agents↗
PubMed1994

A sensitive determination of uric acid in serum using uricase/catalase/formaldehyde dehydrogenase coupled with formate dehydrogenase.

We developed and evaluated an assay for serum uric acid based on the uricase (EC 1.7.3.3)-catalase (EC 1.11.1.6)-formaldehyde dehydrogenase (FADH, EC 1.2.1.46) method coupled with formate dehydrogenase (formate:NAD oxidoreductase, FDH, EC 1.2.1.2). Formate dehydrogenase from Pseudomonas oxalaticus catalyzes the formation of NADH from formate produced by FADH. Owing to the NADH and formate oxidase activity of the FDH itself, the full reaction curve is not linear, but gradually decreases. The formation of NADH is not stoichiometric with formate removal, but is strictly proportional to it. To overcome this decrease of extinction, we added hydroxylamine hydrochloride to the FDH. The sensitivity of the full reaction in the presence of FDH was about 1.8 times that without FDH. Analysis with a Cobas Bio centrifugal analyzer revealed a linearity of up to 3.56 mmol/L. The uricase-catalase-alcohol dehydrogenase method correlated well with the uricase-peroxidase-chromogen method. Our method is more sensitive than other methods.

Aldehyde Oxidoreductases↗
PubMed1994

Enzymatic method for assaying calcium in serum and urine with porcine pancreatic alpha-amylase.

We developed a kinetic assay for calcium in serum and urine, based on the activation of porcine pancreatic alpha-amylase (EC 3.2.1.1) with 2-chloro-4-nitrophenyl-alpha-maltotrioside as substrate. The kinetic generation of 2-chloro-4-nitrophenol, monitored at 405 nm, was proportional to the concentration of calcium in serum and urine. The assay was developed and evaluated with the Cobas Bio centrifugal analyzer. The average within-run and between-day imprecision (CV) was 0.96/1.26% and 1.07/1.63%, respectively, for serum calcium and 1.50/2.54% and 1.70/2.64%, respectively, for urine calcium. Results of the proposed method (y) correlated well with those determined by atomic absorption spectrophotometry (x): y(serum) = 1.005x + 0.028 mmol/L (Sy/x = 0.058, r = 0.974, n = 50), and y(urine) = 1.017x-0.115 mmol/L Sy/x = 0.30, r = 0.981, n = 25). We also present data showing that the method is highly sensitive, rapid, relatively free of interference, and amenable to automation.

Animals↗
PubMed1993

Effect of reduced alcohol consumption on blood pressure in untreated hypertensive men.

Fifty-four untreated, mildly hypertensive men whose daily alcohol consumption was > or = 28 ml ethanol and who drank at least 4 times per week took part in a randomized, controlled crossover trial. The purpose of the trial was to test the effects of alcohol reduction on blood pressure. After a 2-week familiarization period, the participants were assigned to either a reduced alcohol drinking group or a usual drinking group for 3 weeks (experimental period 1). The situation was then reversed for the next 3 weeks (experimental period 2). The participants were requested to limit their daily alcohol consumption to zero or reduce it as much as possible for the reduced alcohol consumption period. The self-reported alcohol consumption was 56.1 +/- 3.6 (SEM) ml/day during the usual alcohol drinking period and 26.1 +/- 3.0 ml/day during the period of reduced alcohol consumption. Systolic and diastolic blood pressures in the intervention group were found by analysis of variance to be significantly lower (2.6-4.8 and 2.2-3.0 mm Hg, respectively) than those in the control group during experimental period 2 for systolic blood pressure and experimental period 1 for diastolic blood pressure. Significant (3.6 mm Hg) and nonsignificant (1.9 mm Hg) decreases in systolic and diastolic blood pressure, respectively, were observed. The method of Hills and Armitage was used, reducing ethanol in daily alcohol consumption by 28 ml. The lowering effect of reduced alcohol consumption on blood pressure was independent of changes in salt consumption, which were estimated by 24-hour urine collection and body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Inhibitory effect of bis(2-aminohexyl) disulfide and bis(2-amino-3-phenylpropyl) disulfide on several mouse inflammations.

The anti-inflammatory profile of the analogues of bis(2-aminopropyl) disulfide dihydrochloride with butyl (compd. II) and phenyl (compd. III) instead of the methyl group was studied in several mouse models related to phagocyte functions. The test samples were administered 2-3 h before the inflammatory stimulation or the peak of inflammation. Subcutaneously administered, compds. II and III significantly inhibited serotonin-induced paw edema in a dose-dependent manner (50% inhibitory dose values: 10 and 5 mg/kg, respectively), when orally administered at 25 mg/kg, these compounds were significantly effective, but their potencies were weaker. Neither compound had any irritant activity when administered at a dose of 12.5 micrograms/5 microliters/paw into the paw. In a sheep red blood cells (SRBC)-induced delayed-type hypersensitivity (DTH) reaction model, compd. II (25 mg/kg, s.c.) significantly inhibited the DTH responses when administered at two different times in relation to the time of challenge. However, there was only slight inhibition by compd. III (25 mg/kg, s.c.) on paw edema formation when administered 14 h after secondary immune response. In a model of experimental acute hepatic failure induced by successive injections of Propionibacterium acnes and lipopolysaccharide, both compounds increased mouse survived, compared with the control mice, and kept the serum levels of components involved in hepatic failure to nearly normal levels. These results demonstrate that compds. II and III possess an inhibitory effect on inflammation related to phagocytes.

Amines↗
PubMed1992

Inhibitory effects of bis(2-aminohexyl)disulfide and its analogues on polymorphonuclear leukocyte functions in vitro.

Water soluble analogues of the anti-inflammatory compound, bis(2-aminopropyl)disulfide dihydrochloride (compd. I) with a butyl (II), phenyl (III), benzyl (IV) or pyrrolidinyl group (V) instead of the methyl group were synthesized, and their effects on the functions of cells related to inflammation were studied in vitro. Compounds II, III and IV showed much higher inhibitory activity than compd. I on formyl Met-Leu-Phe (FMLP)-induced O2(-)-generation of polymorphonuclear leukocytes (PMNs) and platelet aggregation. Compound II showed the strongest activity among the compounds (IC50 values: 2.6 microM). The inhibition of O2(-)-generation of PMNs by compd. II was the most effective when FMLP was used as a stimulant rather than when phorbol myristate acetate, A-23187 and opsonized zymosan were used. However, compd. II was not an O2(-)-scavenger. Compounds II, III and IV significantly inhibited a series of activation processes in PMNs, chemotaxis, phagocytosis and lysosomal enzyme release at doses ranging from 10 to 100 microM. Under these doses, compds II, III and IV did not affect the histamine release from mast cells or the hemolysis of erythrocytes. These results strongly suggest that the anti-inflammatory action caused by compd. II and its analogues was at least partly due to inhibition of several functions of PMNs and platelets.

Amines↗
PubMed1992

Preparation of biologically active and site specifically radioiodinated recombinant human insulin-like growth factor-I.

Recombinant human insulin-like growth factor-I (rhIGF-I) was iodinated using a lactoperoxidase-catalyzed labeling method. The labeled products were separated into more than five fractions by ion-paired reverse-phase high performance liquid chromatography (HPLC). A fraction (peak 1), which showed the highest yield and radioactivity, was found to be biologically active in the BALB/c 3T3 cell proliferating system. The site of the iodination was investigated by S-pyridylethylation followed by trypsinization and separation with HPLC using reverse phase columns. From the amino acid analysis of the peaks which were radioactive, the iodination site of peak 1 was revealed to be Tyr-24 and Tyr-60. This is the first report of the biological activity of radioactive peptide hormone with a defined labeled site.

3T3 Cells↗
PubMed1992

Enzymatic assay of inorganic phosphate with use of sucrose phosphorylase and phosphoglucomutase.

We developed a new enzymatic method for the assay of inorganic phosphate (Pi) by using sucrose phosphorylase (SP; EC 2.4.1.7) and phosphoglucomutase (PGM; EC 5.4.2.2). Pi is transferred to sucrose by SP, producing alpha-D-glucose 1-phosphate (G1P) and alpha-D-fructose. G1P is transphosphorylated by PGM in the presence of alpha-D-glucose 1,6-bisphosphate to form alpha-D-glucose 6-phosphate, which is oxidized by NAD+ and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) to form 6-phosphogluconate (6PG) and NADH. Finally, the oxidation of 6PG by NAD+, catalyzed by 6-phosphogluconic dehydrogenase (EC 1.1.1.44), yields D-ribulose 5-phosphate and NADH. Thus two molecules of NADH are formed for each molecule of Pi, and the reaction is monitored at 340 nm. The Km values of SP for Pi and sucrose were 4.44 and 5.31 mmol/L, respectively. The best buffer was 1,4-piperazinediethanesulfonic acid (PIPES) at 50 mmol/L and pH 6-7. Implementing this method with a Cobas-Bio centrifugal analyzer allowed us to measure Pi accurately and precisely.

Buffers↗
PubMed1991

Localization of metallothionein in nuclei of growing primary cultured adult rat hepatocytes.

In primary cultured adult rat hepatocytes stimulated by epidermal growth factor and insulin, dramatic changes in the subcellular distribution of metallothionein were clarified by indirect immunofluorescence using antisera specific for this protein. Metallothionein was detected only in the cytoplasm of cultured hepatocytes in the G0 and G1 phases, but was concentrated in the cell nuclei in the early S phase. The strongest staining pattern in the nuclei was observed 12 h after stimulation. Subsequently, the intensity of metallothionein staining in the nuclei decreased. These results suggest that primary cultured hepatocytes are suitable for examining the relation between subcellular localization of metallothionein and cell growth.

Animals↗
PubMed1991

Development of an enzymatic method for the assay of serum magnesium using phosphoglucomutase and glucose-6-phosphate dehydrogenase.

We developed an assay for serum magnesium (Mg) by coupling phosphoglucomutase (EC 2.7.5.1) with glucose-6-phosphate dehydrogenase (EC 1.1.1.49). The kinetic generation of NADPH by the action of the above two enzymes upon glucose-1-phosphate (G-1-P) and glucose-1,6-diphosphate (G-1,6-P) was proportional to the concentration of Mg in serum, and was monitored at 340 nm. The average within-run and day-to-day imprecision (% CVs), as determined from 10 replicate analyses for three sera with different Mg concentrations, were 0.8 to 2.1% and 1.9 to 2.7%, respectively. For 60 clinical samples, including several with lipemia and hemolysis, our method showed good agreement with atomic absorption spectrophotometry and the Xylidyl Blue method. We also present data showing that the method is highly sensitive, rapid, relatively free of interference, and amenable to automation.

Cations↗
PubMed1991

Isolation of a new antitumor substance from Bacillus stearothermophilus.

A new antitumor substance, BS-1, was isolated from the autolysate and culture filtrate of Bacillus stearothermophilus UK563 by ethylacetate extraction and HPLC. BS-1 inhibited the proliferation of mouse macrophage-like cells, P388-D1 (IC50: 4 micrograms/ml) and mouse mastocytoma, P-815 (IC50: 0.6 microgram/ml), but not that of Balb/c 3T3.

Animals↗