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Biomedical subjects

J Kato

Publications and source records attributed to J Kato.

At least 37 records · Page 2Linked to original sources
PubMed1978

Continuous production of NADP by immobilized Achromobacter aceris cells.

Several microorganisms having higher nicotinamide adenine dinucleotide kinase (NAD kinase, EC 2.7.1.23) activity were immobilized into polyacrylamide gel lattices. The enzyme activity field by immobilization was highest in Achromobacter aceris AKU 0120. By the incubation of the immobilized A. aceris cells at pH 4.0, the NAD kinase activity increased and the adenosine triphosphate (ATP)-degradation activity disappeared completely. Enzymatic properties of the immobilized A. aceris cells were investigated and compared with those of intact cells. The optimal pH and the optimal temperature of immobilized cells were the same as those of intact cells. Immobilized cell NAD kinase was more stable than that of intact cells. The operational half-life of immobilized cells was 20 days when the substrate solution was passed through a column packed with immobilized cells at a flow rate which gives a space velocity (SV) of 0.1 hr-1 at 37 degrees C. On the other hand, the half-life of the intact cells was only 6 hr.

Adenosine Triphosphate↗
PubMed1978

Age difference in the response to synthetic luteinizing hormone-releasing hormone (LHRH) in androgenized rats with special reference to the dose of testosterone propionate for androgenization.

Five-day-old female rats were androgenized with 1,000 or 100 microgram testosterone propionate and were examined regarding the response to LHRH at 4, 7 and 12 weeks of age by measuring peripheral LH concentrations. The order of magnitude in LH release was 7 greater than 4 greater than 12 weeks old, whereas in normal rats, 4 greater than 12 greater than 7 weeks old. LH release in 4- and 7-week-old rats was higher than that in normal controls at the respective age, but was much lower than that in normal controls 12 weeks old. The LH release by Des-Gly10-(D-Ala6)-LHRH-ethylamide (TAP127) was greater than that by natural LHRH both in normal and androgenized rats at 7 or 12 weeks old. The results indicate that the pituitary gland in androgenized rats responds to LHRH to a much larger extent during the premature period and its responsiveness declines during the course of maturation. A marked hypersensitivity was observed in 7-week-old rats androgenized with 100 microgram testosterone propionate. The process of androgenization may include the induction of alterations in the sensitivity of the pituitary to LHRH and probably in the LH synthesizing ability of the pituitary.

Aging↗
PubMed1977

A case report of a presumptive +i(18p) associated with serum IgA deficiency.

The case of a 4-month-old male infant with retarded psychomotor development and multiple anomalies is presented. Cytogenetic studies on peripheral blood and skin cultures revealed a normal male complement with a supernumerary small metacentric chromosome. According to its size and its banding patterns, the metacentric chromosome was postulated to be an isochromosome for the short arm of number 18. A deficiency of serum IgA was observed in this patient.

Abnormalities, Multiple↗
PubMed1977

Increase in arginine and citrulline production by 6-azauracil-resistant mutants of Bacillus subtilis.

In the arginine producer AHr-5, an L-arginine hydroxamate-resistant mutant of Bacillus subtilis, accumulation of N8-acetyl-L-ornithine increased as the level of L-arginine accumulation increased in the medium containing L-glutamic acid. Ornithine carbamoyltransferase of this strain was genetically derepressed. These results suggested that carbamoylphosphate might be deficient in vivo. With the intention to increase endogenous carbamoylphosphate, pyrimidine analogs inhibiting growth were selected and the mutants resistant to these compounds were derived from the AHr-5 mutant. Of the resistant mutants derived, the 6-azauracil-resistant mutant AAr-9 produced 28 mg of L-arginine per ml, which corresponded to more than twofold the amount produced by the parent strain. Derivation of an arginine-requiring mutant from the double-resistant mutant AAr-9 provides a new advantageous method for the production of L-citrulline. The increase in arginine and citrulline production is discussed.

Arginine↗
PubMed1976

Effect of T-shaped progesterone-releasing system on contraceptive efficacy and menstrual cycle regularity in Japanese monkeys.

Twenty-seven sexually mature Japanese monkeys (Macaca fuscata fuscata) weighing 6 to 8 kg were used to evaluate and characterize the local and systemic effects of a T-shaped progesterone-releasing system (UTS) following transabdominal insertion into the uterus. None of five experimental animals conceived, while four of five sham-operated control animals and all intact animals conceived. The general physical appearance, behavior, and clinical blood chemical titer of animals receiving the UTS were comparable with those of the sham-operated group. The UTS also had no significant effect on the cyclic vaginal smear pattern and serum luteinizing hormone (LH) surge during the ovulatory interval. The time course of radioactivity, determined in serum obtained serially following intrauterine insertion of a tritiated UTS, revealed the immediated appearance of 3H in serum, and the levels increased rapidly and remained high for 1 to 1.5 months. The LH release pattern in peripheral blood induced by the intravenous injection of 100 mug of LH-releasing hormone was not affected by the device in utero. The UTS did not appear to interfere with systemic function; when placed in the uterine cavity, the UTS appears to release steroid locally and to exert its antifertility effect without affecting the hypothalamic-pituitary-ovarian axis. A characteristic of the UTS is its effectiveness, since it has both mechanical and hormonal contraceptive properties.

Animals↗
PubMed1976

L-Norvaline and L-homoisoleucine formation by Serratia marcescens,.

Two unnatural amino acids were found as by-products in isoleucine fermentation from threonine by Serratia marcescens. These amino acids were identified as L-norvaline (2-aminopentanoic acid) and L-homoisoleucine (2-amino-4-methylhexanoic acid). Formation of L-norvaline and L-homoisoleucine was not observed when L-leucine was added to the medium. The leucine auxotroph derived from the isoleucine accumlator did not produce L-norvaline or L-homoisoleucine even during the accumulation of large amounts of isoleucine. It is suggested that L-norvaline and L-homoisoleucine formation is closely related to leucine biosynthesis.

Isoleucine↗
PubMed1976

Renal angiotensin I-converting enzyme as a mixture of sialo- and asialo-enzyme, and a rapid purification method.

Angiotensin I-converting enzyme [EC 3.4.15.1] was rapidly and highly purified from a particulate fraction of hog kidney cortex with 13% yield. The procedure, which was rapid, included fractionation on DEAE-cellulose and calcium phosphate gel, chromatographies on DEAE-Sephadex A-50 and hydroxylapatite columns, and gel filtration on a Sephadex G-200 column. The purified enzyme preparation gave two protein bands on standard disc gel electrophoresis, but showed a single protein component on the gel after treatment with neuraminidase [EC 3.2.1.18]. The data strongly suggest that the purified enzyme preparation was a mixture of sialo- and asialo-enzyme. Sialic acid residues apparently do not contribute to the catalytic activity of the enzyme. The enzyme was activated more by chloride ions than by other halide ions tested, using Bz-Gly-Gly-Gly as a substrate. The dissociation constant for chloride ions was determined to be 2.2 mM. Chloride did not protect the enzyme against heat or low pH. The enzyme was resistant to inactivation by trypsin [EC 3.4.21.4] and chymotrypsin [EC 3.4.21.1].

Animals↗