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Biomedical subjects

H Naruse

Publications and source records attributed to H Naruse.

At least 127 records · Page 7Linked to original sources
PubMed1981

Evidence that a polysaccharide from the cortex of sea urchin egg inhibits microtubule assembly through its binding to microtubule-associated proteins.

A new factor that not only inhibits brain microtubule assembly but also causes depolymerization of pre-assembled microtubules was purified from unfertilized sea urchin egg cortices. The purified fraction contained neither proteins nor nucleic acids. The inhibitory activity of the fraction was heat-stable and insensitive to various proteases, but decrease on treatment with glycosidases or with periodic acid. The purified factor was identified as a polysaccharide by analysis of the sugar composition. The sedimentation constant of the factor was estimated to be 9S by sucrose density gradient centrifugation. Polyacrylamide gel electrophoresis of the factor revealed a single broad band stained with periodic acid-Schiff reagent. The factor completely inhibited microtubule assembly at a factor: microtubule protein ratio of 0.03 (w/w). The polysaccharide was found to bind to microtubule-associated proteins, thereby inhibiting microtubule assembly.

Animals↗
PubMed1981

A new method of blood galactose estimation for mass screening of galactosemia.

A new method for quantitative determination of galactose in blood by fluorescence of NADH was described. The assay system consisted of beta-galactose dehydrogenase, NAD, buffer and a denatured blood disc (3 mm diameter), and the reaction was carried out for 1 hr at 37 degrees C. Denaturation of hemoglobin was accomplished by exposing the blood disc to a vapor of formic acid in an air-tight container; this procedure completely eliminated false positive cases of galactosemia. This method can be applied in a wide range of galactose concentration from low (0 mg%) to high levels (200-1,000 mg%) with the accuracy of 8.0 +/- 0.3 mg% from a coefficient of variation of 3.5%. Semi-quantitative assay was also possible by using a spot test like Beutler's method. The galactose content in one disc paper (3 mm diameter) of blood containing 5 mg% galactose is approximately 0.1 micrograms. The newly developed method is satisfactorily applicable in neonatal mass screening and clinical cases.

False Positive Reactions↗
PubMed1980

A new mass screening method of detecting UDP-galactose-4-epimerase deficiency.

A new mass screening method for detecting UDP-galactose-4-epimerase deficiency in newborn infants was devised so as to make a useful addition to the Guthrie test. Like Beutler's method, this method enables one to perform convenient spot tests on the basis of fluorometry of NADH. The preferred procedure was determined to be as follows: To a mixture of 10 microliter of 5-10 mM UDP-galactose, 10 microliter of 26 mM NAD, 10 microliter of a 1 M tris-HCl buffer (pH 8.0) and 10 microliter of a 1/100 dilution of a 5 mg/ml UDP-glucose dehydrogenase stock solution, distilled water is added until the total volume reaches 100 microliter. Then a blood-bearing filter paper disc is added to the mixture and, the reaction mixture is incubated at 37 degrees C for 6-17 hr. The resulting test solution is spotted on a Whatman No. 1 filter paper with a capillary tube, air-dried and tested for fluorescence with an ultraviolet light detector. No cases of UDP-galactose-4-epimerase deficiency were found in the present study.

Carbohydrate Epimerases↗
PubMed1978

Inhibitory factor of microtubule assembly from sea urchin egg cortex. I. Preparation and characterization.

A new inhibitory factor of the microtubule (MT) assembly system was isolated from unfertilized sea urchin egg cortex. This factor not only suppressed spontaneous brain MT assembly, but also induced depolymerization of the reconstituted MTs. The factor did not suppress initial MT growth initiated by ciliary outer fiber fragments but the assembled MTs were soon depolymerized with time. The inhibitory activity was heat-stable but sensitive to trypsin or urea. The mode of the inhibition was distinct from the inhibitory effects of RNA on the MT assembly. The inhibitory factor partially purified on DEAE-Sephadex A-50 completely inhibited tubulin polymerization in a factor: tubulin ratio of 0.013.

Animals↗
PubMed1975

Measurement of thyroid-stimulating hormone in dried blood spot.

Blood T.S.H. (thyroid-stimulating hormone) was measured by radioimmunoassay in dried blood spotted onto filter-paper and obtained during screening of the newborn for metabolic disorders. By this method, the detection limit for blood T.S.H. was 5--10 muU/ml, which is the approximate upper limit of normal for blood T.S.H. T.S.H. values obtained on dried blood correlated well with those obtained on serum from the same subjects. Duplication of the assay in a single sample is not necessary. This method picked up a case of primary hypothyroidism in a four-year-old girl with symptoms. Since the technique is simple and sensitive enough for the detection of hypothyroidism, it could be valuable in mass-screening for congenital hypothyroidism.

Adult↗
PubMed1970

A study on the precursors of the acetyl moiety of acetylcholine in brain slices. Observations on the compartmentalization of the acetyl-coenzyme A pool.

1. A method was devised for the determination of the specific radioactivity of the acetyl moiety of acetylcholine synthesized from various (14)C-labelled substrates. 2. The precursor for the acetyl moiety of acetylcholine was studied in slices of striatum and cerebral cortex from rat and guinea-pig brain. Incorporation of radioactivity into acetylcholine was determined after incubating the slices in the presence of [2-(14)C]acetate, [(14)C]bicarbonate, [1,5-(14)C]citrate, dl-[1- or 5-(14)C]glutamate or [1- or 2-(14)C]pyruvate. 3. After incubation for 1h, acetylcholine was accumulated significantly in both striatum slices (4.1nmol/mg of protein) and cerebral-cortex slices (0.57nmol/mg of protein) from the rat. Final concentrations were about 11 and 5 times respectively the initial values. 4. With slices from rat striatum, rat cerebral cortex and guinea-pig cerebral cortex, the specific radioactivity of acetylcholine derived from [2-(14)C]pyruvate was very high, reaching approx. 30, 20 and 6% respectively of the initial specific radioactivity of added pyruvate in the medium. With the striatum slices this high value was reached after incubation for 15min. Incorporation of radioactivity from [2-(14)C]acetate was only 1.25, 5.3 and 19.7% of that from [2-(14)C]pyruvate in rat striatum, rat cerebral-cortex and guinea-pig cerebral-cortex slices respectively. A small but definite incorporation was found from [5-(14)C]glutamate. No incorporation was found from the other substrates. The findings suggest that pyruvate is the most important precursor for the synthesis of the acetyl moiety of acetylcholine in brain slices. 5. The specific radioactivity of acetylcholine relative to that of citrate when [2-(14)C]pyruvate was used compared with that obtained when [2-(14)C]acetate was used. A marked difference was found in all slices, suggesting metabolic compartmentation of the acetyl-CoA pool.

Acetates↗