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Biomedical subjects

S Arai

Publications and source records attributed to S Arai.

At least 343 records · Page 19Linked to original sources
PubMed1988

Oligopeptide mixtures produced from soy protein by enzymatic modification and their nutritional qualities evaluated by feeding tests with normal and malnourished rats.

Soy protein isolate (SPI) was enzymatically modified to produce oligopeptide mixtures having methionine at approximate levels of 1% and 3%. Each of them had an average molecular weight of slightly lower than 1,000 daltons. They were compared with corresponding amino acid mixtures as well as with SPI for protein efficiency ratio (PER) and several other parameters. Normal and protein-malnourished rats were used as subjects for the comparison tests. When malnourished rats were subjected to a feeding test at a methionine level of 1% in nitrogen source, the oligopeptide mixture, OPM1, gave a significantly higher PER value than any of SPI and the amino acid mixtures. At a methionine level of 3%, both normal and malnourished rats utilized the oligopeptide mixture, OPM3, with higher efficiency than the amino acid mixture. These results suggest that the oligopeptide mixtures were utilized similarly to or more efficiently than SPI from which they were derived and the amino acid mixtures with exactly simulated amino acid composition.

Amino Acids↗
PubMed1988

Bleomycin-stimulated hamster alveolar macrophages release interleukin-1.

The capacity of alveolar macrophages (AM) of bleomycin-instilled hamsters to proliferate mouse thymocytes (interleukin-1 activity) and hamster fibroblasts (fibroblast proliferation (FP) activity was studied. Using bleomycin-instilled hamsters, the FP activity of AM culture supernatants was increased significantly on days 1, 5, and 10 after instillation of bleomycin. The interleukin-1 (IL-1) activity, however, was increased significantly on day 1 only as compared with saline-treated hamsters. Next, normal AM were stimulated in vitro by bleomycin. After being fractionated by chromatography, their culture supernatant showed IL-1 activity, which also indicated FP activity. These results suggest that bleomycin directly stimulates AM to release IL-1 in the fibrogenic responses.

Animals↗
PubMed1988

[A case of neonatal meningitis due to Flavobacterium meningosepticum successfully treated with cefmetazole and cefotaxime].

A 3-day-old male infant, weighing 3,413 g and a gestational age of 38 weeks developed neonatal meningitis due to Flavobacterium meningosepticum. Treatment with cefmetazole and cefotaxime led him to a complete recovery without neurologic deficit. Of 82 previously published cases under 1 year old, 41 cases died and 16 of survivors developed hydrocephalus because the organism was resistant to many antibiotics. Therapy of meningitis due to the organism has not been standardized but the early laboratory identification and the choice of effective and safe antibiotics determined by antimicrobial sensitivity test improve the outcome.

Cefmetazole↗
PubMed1988

[In vitro synergy between cefotaxime and its main metabolite, desacetylcefotaxime].

In vitro synergistic interaction between cefotaxime (CTX) and its main metabolite, desacetyl-cefotaxime (DCTX), against 7 species of clinical isolates (23-27 strains per species) was examined. Complete or partial synergy was noted with a 1:1 combination of CTX and DCTX against 22-78% of the Bacteroides fragilis, Staphylococcus aureus, Citrobacter freundii, Pseudomonas cepacia and Enterobacter cloacae isolates examined. Antagonistic effects of the drugs appeared against 11% of Proteus vulgaris and 4% of Serratia marcescens. When combined at various ratios by the checkerboard method and tested against B. fragilis, CTX and DCTX were found to act synergistically, and no antagonism occurred. The combined use of CTX and DCTX exhibited strong bactericidal activity against B. fragilis and inhibited bacterial regrowth. An experiment with concentrations of CTX and DCTX simulating human serum levels after intravenous administration also showed that the coexistence of DCTX augmented bactericidal activity of CTX against B. fragilis and brought inhibitory effects on bacterial regrowth. It is presumed from the present results that clinically applied CTX would have more potent effects than expected from in vitro sensitivity test data.

Bacteria↗
PubMed1988

[Positron emission tomography using pyruvate-1-11C on mitochondrial encephalomyopathy].

In order to investigate in vivo metabolism of pyruvate in the brain, positron emission tomography (PET) using pyruvate-1-11C were performed on two patients with mitochondrial encephalomyopathy, one patient with Leigh disease and one patient with epilepsy. PET images of epilepsy showed less RI uptakes in brain tissues than in skull muscles. And RI was cleared rapidly from the brain tissues. But PET images of mitochondrial encephalomyopathies showed increased RI uptakes and slow RI clearance in cerebral cortices, basal ganglia and thalamus. Also RI was cleared slowly or accumulated in ventricles. This suggested that pyruvate metabolism may be impaired with metabolical trapping of 11C by lactic acids, since it is said that 11C of pyruvate-1-11C is cleared rapidly from the normal brain tissues by decarboxylation of pyruvate. The usefulness of PET studies with pyruvate-1-11C are suggested for investigating pyruvate metabolism in brain tissues, and for diagnosing mitochondrial encephalomyopathy.

Brain↗
PubMed1987

Molecular cloning of a cysteine proteinase inhibitor of rice (oryzacystatin). Homology with animal cystatins and transient expression in the ripening process of rice seeds.

A cDNA clone for a cysteine proteinase inhibitor of rice (oryzacystatin) was isolated from a lambda gt10 cDNA library of rice immature seeds by screening with synthesized oligonucleotide probes based on partial amino acid sequences of oryzacystatin. A nearly full-length cDNA clone was obtained which encoded 102-amino acid residues. The amino acid sequence of oryzacystatin deduced from the cDNA sequence was significantly homologous to those of mammalian cystatins, especially family 2 cystatins. Oryzacystatin contained the sequence Gln-Val-Val-Ala-Gly conserved among most members of the cystatin superfamily. The gene for oryzacystatin was transcribed into a single mRNA species of about 700 nucleotides. The content of mRNA reached its highest level 2 weeks after flowering and then gradually decreased to undetectable levels at 10 weeks. This feature of transient expression is coordinate with that of glutelin (a major storage protein), although the expression of oryzacystatin precedes that of glutelin by about 1 week.

Amino Acid Sequence↗
PubMed1987

Production of factor(s) that render polymorphonuclear leukocytes cytostatic from spleen cells stimulated with a streptococcal preparation, OK-432.

We previously reported the augmentation of tumor cytotoxicity of polymorphonuclear leukocytes (PMN) by in vivo administration of a streptococcal preparation, OK-432 (S. Watabe et al., J. Natl. Cancer Inst., 72: 1365-1370, 1984). The present study was undertaken to elucidate the mechanisms of the phenomena. Mouse and rat spleen cells were stimulated in vitro with OK-432. The culture supernatants from the stimulated spleen cells (OK sup) contained factor(s) that rendered mouse and rat PMN cytostatic [neutrophil activating factor (NAF)]. The stimulation of spleen cells with a small dose of OK-432 (0.05 micrograms/ml) resulted in the production of maximum NAF, and NAF was produced soon (12 h) after OK-432 stimulation. NAF was partially inactivated with 60 degrees C 30-min treatment, and completely inactivated with 100 degrees C 10 min. NAF was sensitive to pH 2 treatment. The treatment of PMN with OK sup for 5 min at 37 degrees C was sufficient to induce cytostatic activity of PMN. That OK sup contained gamma-interferon and recombinant gamma-interferon showed NAF activity indicate that gamma-interferon is a NAF in OK sup.

Animals↗
PubMed1987

In vivo antitumor effect of lymphokine-activated rodent polymorphonuclear leukocytes.

In vivo tumor inhibitory activity of polymorphonuclear leukocytes (PMN) treated in vitro with lymphokine(s) (LK) was investigated with Winn's assay. Culture supernatants of BALB/c mouse spleen cells incubated with a streptococcal preparation, OK-432, were used as an LK source. With the use of a [3H]uridine release assay, RL male-1 tumor cells were lysed to some extent by peritoneal BALB/c mouse PMN treated with this LK preparation. With Winn's assay, LK-treated PMN from BALB/c mice completely inhibited the growth of the admixed syngeneic tumor at a high effector to target ratio, when normal mice were used as recipients. When X-irradiated mice or nude mice were used as recipients, the tumor growth was partially inhibited by admixed LK-treated PMN, but the tumor began to grow gradually and finally killed the recipient mice, even when a high effector target ratio was used. When nude mice which had been given i.v. transfers of nylon wool column effluent spleen cells were used as recipients, the tumor inhibitory activity of LK-treated PMN was recovered to the same level as when normal mice were used as recipients. On the other hand, tumor inhibition by admixed LK-treated PMN in nude mice was not recovered by the transfer of X-irradiated nylon column effluent T-cells. As a mechanism of tumor inhibition by LK-treated PMN, a possible role of LK-treated PMN in reduction of tumor load is discussed.

2-Chloroadenosine↗
PubMed1987

Tumor cytotoxicity of polymorphonuclear leukocytes in beige mice: linkage of high responsiveness to linear beta-1,3-D-glucan with the beige gene.

Beige mice (bg/bg) have many functional defects in their leukocytes and these phenotypes are inherited autosomal recessively. We studied the tumor cytotoxicity of polymorphonuclear leukocytes (PMN) obtained from bg/bg. The intensity of tumor cytotoxicity of PMN induced by linear beta-1,3-D-glucan was significantly higher in bg/bg PMN than in PMN of heterozygous control mice (bg/+). To analyze this phenomenon more precisely from the genetic viewpoint, we determined the tumor cytotoxicity of PMN from mice obtained by several mating experiments. (a) The intensity of linear beta-1,3-D-glucan-induced PMN cytotoxicity was found to be genetically defined and linked completely with the beige gene. In litter mates obtained from bg/+(female) X bg/bg(male), bg/bg(female) X bg/+(male), and bg/+(female) X bg/+(male) mating, PMN from only bg/bg showed significantly higher tumor cytotoxicity than those from bg/+ or mice that do not possess the beige gene (+/+). (b) The tumor cytotoxicity induced by other stimulants (phorbol myristate acetate and cytokines) was not significantly higher in bg/bg than bg/+ or +/+ PMN. It was concluded that the high responsiveness to linear beta-1,3-D-glucan in terms of tumor cytotoxicity of PMN was determined by the locus that is linked to the beige gene and is expressed autosomal recessively.

Animals↗
PubMed1987

T cell mitogenicity of a novel beta-D-galactoside-specific lectin from the beetle, Allomyrina dichotoma (allo A).

We examined the lymphocyte mitogenicity of a novel beta-D-galactoside-specific lectin from the beetle Allomyrina dichotoma, named allo A. Allo A was mitogenic to spleen cells of various strains of mice and rats and to human peripheral blood lymphocytes. When the selectivity of mitogenicity to T or B lymphocytes was examined with mouse spleen cells, allo A was selectively mitogenic to T-enriched spleen cells, which indicates that allo A is a T cell mitogen. Thymocytes from non-treated mice hardly responded to allo A, while those from cortisone-treated mice did to a great extent, indicating that allo A is mitogenic to mature thymocytes. The lymphocyte activation with allo A was inhibited by lactose, but not by melibiose, N-acetyl-D-glucosamine, or methyl-alpha-D-mannoside, which suggests that cell surface molecules containing beta-D-galactosyl residues are of importance in the structure of allo A receptors on the cell surface.

Animals↗
PubMed1987

Induction of interferon production by natural killer cells by organogermanium compound, Ge132.

Interferon (IFN)-inducing activity of the organogermanium compound Ge132 in human peripheral mononuclear cells was investigated. By using Percoll discontinuous density gradient centrifugation, peripheral blood nonphagocytic and nonadherent mononuclear cells were divided into the low-and high-density fractions. Natural killer (NK)-enriched low-density fractions, but not the T-cell-enriched high-density fractions, showed IFN production by the stimulation of Ge132. The maximal titer of IFN by NK-enriched fractions (F1 + F2) was observed after a 74-h cultivation in the presence of 200 micrograms/ml Ge132. IFN production by the NK-enriched fractions was abrogated by treatment of the cells with monoclonal antibody against human NK cells in the presence of complement. The treatment with antiserum-neutralizing human IFN-gamma resulted in a marked reduction, indicating that a major part of IFN was IFN-gamma. These results suggested that Ge132 might possess affinity to NK cells, inducing IFN production by NK cells.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Effects of rokitamycin and other macrolide antibiotics on Mycoplasma pneumoniae in L cells.

Fifty strains of Mycoplasma pneumoniae in L cells were tested for susceptibility to macrolide antibiotics. Rokitamycin, a new macrolide antibiotic, was most active against these organisms, with an MIC for 90% of strains of 0.007 microgram/ml. The MICs of erythromycin, josamycin, and kitasamycin for 90% of strains were 0.03, 0.03, and greater than or equal to 0.06 microgram/ml, respectively. Based on these results, rokitamycin is a promising antibiotic for the treatment of mycoplasmal infections, and further clinical investigations are needed.

Anti-Bacterial Agents↗
PubMed1987

Treatment of phenylketonuria with a formula consisting of low-phenylalanine peptide. A collaborative study.

A method of preparation of a more palatable therapeutic formula for phenylketonuria (PKU), consisting of low-phenylalanine peptide (LPP), was reported. There were no adverse effects and, in fact, there was a reduced frequency of diarrhea in patients who received LPP formula for more than 6 months. The LPP formula can be used not only as a more palatable therapeutic milk for PKU, but also as an ingredient to make more palatable foods of low-phenylalanine content.

Adolescent↗