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Biomedical subjects

K Kohda

Publications and source records attributed to K Kohda.

At least 145 records · Page 8Linked to original sources
PubMed1983

Semi-automated continuous-flow enzyme immunoassay for antiepileptic drugs in serum.

We have developed a semi-automated method for measuring five kinds of antiepileptic drugs in serum by successfully adapting commercial competitive-binding enzyme immunoassay kits (MARKIT; Dainippon) for use with a continuous-flow analyzer (Technicon AutoAnalyzer II equipped with a dialyzer). The free enzyme-labeled drug is automatically separated by a microfilter from the competitive immunoreaction mixture between labeled and unlabeled drug for anti-drug immunoglobulin coupled to bacterial cell walls. The concentrations of the antiepileptic drugs in serum samples can be determined by automated measurement of enzyme activity of the enzyme-labeled drugs. Results of the semi-automated method correlated well with those obtained by manual enzyme immunoassay, gas-liquid chromatography, and "high-pressure" liquid chromatography. The correlation coefficients were all greater than 0.95, showing the practicality of this method for therapeutic monitoring of antiepileptic drugs.

Anticonvulsants↗
PubMed1982

A new enzymatic method to determine creatine.

A new enzymatic method is described for the determination of creatine in serum and urine using creatine amidinohydrolase (EC 3.5.3.3), sarcosine oxidase (EC 1.5.99.1) and formaldehyde dehydrogenase (EC 1.2.1.1). The principle of the method is as follows. Creatine is degraded to sarcosine and urea, and the sarcosine formed is measured with sarcosine oxidase in the presence of formaldehyde dehydrogenase and NAD+. The NADH + H+ produced is measured at 340 nm. Creatine concentration can be calculated directly from the absorptivity of NADH + H+ generated in the reaction or from creatine standard solutions. The assay takes less than 20 min. The standard curve is linear up to 50 mg creatine/1 (serum) and 800 mg creatine/1 (urine). Fifty random samples were assayed by this method (y) and simultaneously by the Folin method (x). The correlation coefficients were 0.995 for serum samples, 0.994 for urine samples, and the regression equations were y = 0.979x - 0.01 (serum) and y = 0.978x - 0.01 (urine).

Aldehyde Oxidoreductases↗
PubMed1982

Assays of serum lipase by the "BALB-DTNB method" mechanized for use with discrete and continuous-flow analyzers.

We successfully adapted the dimercaprol (BAL) tributyrate-5,5'-dithiobis(2-nitrobenzoic acid) method (J. Biochem. 81: 361, 1977) for assay of lipase in human serum to a discrete analyzer (the TBA 880) (I) or a continuous-flow analyzer (AutoAnalyzer, Type II) (II). In both, BAL-tributyrate is used as substrate, in combination with serum esterase inhibitors and a chromogenic reagent for the SH group of the liberated BAL. Serum lipase activities of patients with pancreatic diseases, measured at 90 or 40 samples per hour by I or II, respectively, correlated well with those measured by the corresponding manual method or by Kaplan's radioassay (Anal. Biochem. 33: 213, 1970). The correlation coefficients were all greater than 0.95, and the coefficients of variation were less than 8%, showing the practical usefulness of these procedures.

Autoanalysis↗
PubMed1981

Continuous-flow enzymic determination of creatine in urine.

A new enzymic method is described for the determination of creatine in urine by continuous-flow analysis. The measurement is accomplished by transforming creatine to formaldehyde in reactions catalyzed by creatinase (creatine amidinohydrolase) and sarcosine dehydrogenase. The formaldehyde is reacted with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to form a purple product, which is measured colorimetrically. The method gives a linear standard curve for creatine concentrations up to 100 mg/L. Precision and analytical recovery are excellent, and results correlate well with those by the more-difficult Folin method, which currently is most often used for this analysis.

Autoanalysis↗
PubMed1979

Various antigenic reactivities in delayed hypersensitivity among crystalline proteins from Mycobacterium phlei.

Comparisons were made of the delayed-type skin reactivity of 6 crystalline proteins purified from the cell extract of Mycobacterium phlei in guinea pigs sensitized with whole cells of the heat-killed bacillus. These highly purified proteins elicited varying degrees of cutaneous reaction. The most active protein had almost the same reactivity as purified protein derivative prepared from the culture filtrate of Mycobacterium phlei. On the other hand, the weakest protein did not elicit a marked cutaneous reaction even after injection of 3,000 times the amount of protein of the most potent one. The other 4 proteins showed moderate reactivities. The difference in antigenic potency between proteins is probably due not to the amounts of the proteins contained in the cells used for sensitization, but to their structure.

Animals↗