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Biomedical subjects

S Goto

Publications and source records attributed to S Goto.

At least 829 records · Page 46Linked to original sources
PubMed1988

Inactivation kinetics of horseradish peroxidase microinjected into hepatocytes from mice of various ages.

We have studied degradation of proteins in liver parenchymal cells in culture obtained from mice of various ages. Horseradish peroxidase (HRP) was microinjected into the cells by the hypertonic-hypotonic method of Okada and Rechsteiner (Cell, 29 (1982) 33-41). Rate of inactivation of HRP was examined biochemically. Average functional half-lives of the enzyme were 50 h, 53 h and 75 h in the cells of young (3-8 months old), middle-aged (18-20 months old) and old (28-30 months old) mice, respectively. Thus, half-life of the inactivation of the enzyme in "old" cells was about 50% longer than that in "young" or "middle-aged" cells, suggesting that rate of protein degradation is lowered in senescent animals.

Aging↗
PubMed1988

Taurine and beta-alanine act on both GABA and glycine receptors in Xenopus oocyte injected with mouse brain messenger RNA.

The responding pathway (process from agonist binding to channel opening) of taurine and beta-alanine was investigated in Xenopus oocytes injected with mouse brain poly(A)+ RNA. Responses to gamma-aminobutyric acid (GABA), glycine, taurine and beta-alanine were induced in oocytes injected with poly(A)+ RNA extracted from 3 regions, cerebrum, cerebellum and brainstem of the mouse brain. From comparison, responses to these 4 inhibitory amino acids in each regional poly(A)+ RNA-injected oocytes were categorized into at least 3 groups: (1) GABA, (2) glycine, and (3) taurine and beta-alanine. No cross-desensitization was observed between GABA response and glycine response, but taurine and beta-alanine responses cross-desensitized both the GABA and glycine responses. Taurine and beta-alanine responses were partially inhibited by the GABA antagonist, bicuculline, and also by the glycine antagonist, strychnine. The results suggest that the taurine or the beta-alanine response in the brain is caused through both the GABA receptor and the glycine receptor.

Alanine↗
PubMed1988

Taurine modulates glycine response in Xenopus oocytes injected with messenger RNA from mouse brain.

The modulatory action of taurine on the glycine response was investigated in Xenopus oocytes injected with messenger RNA from mouse brainstem under voltage-clamped condition. Taurine competitively inhibited the glycine response in a dose-dependent manner. This inhibition was insensitive to bicuculline and intracellularly injected EGTA. The results suggest that taurine could directly modulate glycinergic neurotransmission in the central nervous system.

Animals↗
PubMed1988

ID sequence-binding protein factors during development of mice.

The ID repetitive sequence has been reported to be transcribed as small RNA in both a brain-specific and a developmental stage-specific manner. Several brain-specific proteins required for transcription, along with RNA polymerase III, may be involved in controlling the gene activity throughout development. We analyzed extracts from the brains and livers of mice in an electrophoretic mobility shift assay. Of ID sequence-binding proteins, we detected a protein factor(s) that interacts specifically with the region between two promoter sequences for RNA polymerase III. This protein factor seems to be relevant to postnatal accumulation of the small RNA transcripts of ID sequences, since its time course of expression is consistent with that of the synthesis of the small RNA during development. A penta-nucleotide direct repeat (GCAAG) and its inverted complement (CTTGC) are both present in that region and may be involved in the binding site for the protein factor. The biological significance of the binding site and interacting protein factor(s) is discussed.

Aging↗
PubMed1988

Nature of monocyclic beta-lactam antibiotic Nocardicin A to beta-lactamases.

Nocardicin A is the antibiotic which was first found to possess a monocyclic beta-lactam ring. This antibiotic was inactivated by the cleavage of its beta-lactam ring. The direct spectrophotometric assay was applied to measure the rate of enzymatic hydrolysis of Nocardicin A. Nocardicin A was highly stable to both chromosomal and plasmid-mediated beta-lactamases. Of the nine beta-lactam antibiotics including cefoxitin and cefuroxime, Nocardicin A was the most stable to the beta-lactamases tested excluding those from Klebsiella oxytoca and Proteus vulgaris. The latter broad-spectrum beta-lactamases hydrolyzed Nocardicin A rather intensively. Extreme stability of Nocardicin A to beta-lactamases was suggested to be due to the combination of its low affinity to the enzymes and stabilization of its monocyclic beta-lactam ring. Nocardicin A was shown to have inducing ability toward beta-lactamases.

Anti-Bacterial Agents↗
PubMed1988

The existence of specific antibodies to cobalt in hard metal asthma.

Twelve workers with hard metal asthma diagnosed on the basis of peak flow diaries and positive bronchial reactions to cobalt chloride (CoCl2) were studied for sensitization by detection of specific antibodies to radioactive cobalt (57Co), cobalt-conjugated human serum albumin (Co-HSA) and cobalt-conjugated exchange resin (Co-resin). Their IgE titres ranged from 73 to 1500 IU/ml and eight were atopic individuals. Sixty serum samples from asthmatic patients with IgE titres of 14-4300 IU/ml were studied as controls in all tests. Eleven of twelve subject sera that selectively bound to 57Co after incubation with saturated ammonium sulphate (greater than 232 c.p.m., P less than 0.01) were divided into three groups: (1) six sera showing evidence of specific IgE antibodies to Co-HSA (greater than 673 c.p.m., P less than 0.01) without those to Co-resin; (2) one serum giving a positive radio-allergosorbent test (RAST) only to Co-resin (greater than 417 c.p.m., P less than 0.01), and (3) four sera that were negative for two antigenic agents (Co-HSA, Co-resin). These results suggest that the subjects had occupational asthma due to hard metal exposure from cobalt sensitivity. An immuno-allergic mechanism mediated by specific IgE antibodies to cobalt was confirmed to be responsible for the development of hard metal asthma, with the possibility of some role of the reaction without reagins.

Adult↗
PubMed1988

Localization of glycogen synthase in brain.

Antisera against glycogen synthase from canine brain were prepared and used for investigation of the localization of the enzyme in the brain. Antisera cross-reacted only with the 88-kilodalton protein that is the subunit of brain glycogen synthase. Immunoreactivity of glycogen synthase was universally distributed in all regions of the brain, although hippocampus, cerebral cortex, caudatoputamen, and cerebellar cortex had relatively high immunoreactivity. Light microscopic examination revealed that the immunoreactivity was found in all cell types, such as neurons in several regions, astrocytes, ependymal cells surrounding the ventricle, oligodendrocytes, and epithelial cells of the choroid plexus in the ventricle. Immunoreactive intensity was more prominent in neurons than glial cells. Immunostaining may be a useful tool for investigation of the state of glycogen metabolism under normal and pathological conditions.

Animals↗
PubMed1988

Immunohistochemical localization of Ca2+/calmodulin-dependent protein kinase II in rat brain and various tissues.

Polyclonal antibodies against Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) of rat brain were prepared by immunizing rabbits and then purified by antigen-affinity column. The antibodies which recognized both subunits of the enzyme with Mrs 49K and 60K were used for the study on the distribution of CaM kinase II in formalin-fixed, paraffin-embedded tissues. In the brain, a light-microscopic study demonstrated strong immunoreactivity in neuronal somata and dendrites and weak immunoreactivity in nuclei. The densely stained regions included cerebral cortex, hippocampal formation, striatum, substantia nigra, and cerebellar cortex. In substantia nigra, neurites were stained, but not neuronal somata. Electron microscopy revealed that the immunoreactive product was highly concentrated at the postsynaptic densities. In addition to neurons, weak immunoreactivity was also demonstrated in glial cells, such as astrocytes and ependymal cells of ventricles and epithelial cells of choroid plexus. In other tissues, strong immunoreactivity was observed in the islet of pancreas and moderate immunoreactivity in skeletal muscle and kidney tubules. Immunoreactivity was demonstrated in all of the tissues tested. The results suggest that CaM kinase II is widely distributed in the tissues.

Animals↗
PubMed1988

Degradation of host defenses against respiratory tract infection by Klebsiella pneumoniae in aged mice.

The host defense against respiratory tract infection with Klebsiella pneumoniae was much weaker in 60-week-old mice than in 4-week-old mice, but the resistance against systemic infection by intravenous and intraperitoneal challenge with K. pneumoniae in 60-week-old mice did not differ from that in 4-week-old mice. The number of alveolar macrophages at the resting stage in 60-week-old mice was the same as in 4-week-old mice, but the number of macrophages and polymorphonuclear leukocytes in the pulmonary cavity 4 h after challenge with formalinized K. pneumoniae in aerosol doubled in parallel with body weight. Phagocytosis and killing activities and superoxide anion production as measured by the Nitro Blue Tetrazolium reduction test of alveolar macrophages in 60-week-old mice were significantly weaker than in 4-week-old mice. The surfaces of the alveolar macrophages of the 60-week-old mice shrunk and a few adhered weekly to the glass plate, but the alveolar macrophages of the 4-week-old mice stretched to their full length and adhered firmly to the glass plate. These functions of alveolar macrophages clearly differed from those of peritoneal macrophages in 60-week-old mice, but those of the peritoneal phagocytes did not differ between 60-week-old and 4-week-old mice. The results suggest that the susceptibility to respiratory tract infection in 60-week-old mice is affected by a decline in the functions of alveolar macrophages rather than by the number of alveolar macrophages and exudated polymorphonuclear leukocytes in the lungs.

Aging↗
PubMed1988

Determination of gamma-aminobutyric acid and associated amino acids in mouse brain by liquid chromatography.

A rapid method is described for the analysis of amino acids containing in mouse brain by high performance liquid chromatography equipped with a fluorescence detector. Pre-column o-phthalaldehyde-2-mercaptoethanol derivatives of the amino acids were injected onto an ODS C-18 column. 5-Amino-n-valeric acid, a non-endogenous amino acid, was used as an internal standard. Separation and elution of amino acid derivatives were achieved by varying the ratio of organic phase by a step gradient. Significant increases in gamma-aminobutyric acid, glutamine and glycine levels in the brain were detected 2 h after injection of 800 mg/kg valproic acid (VPA). A high dose administration of VPA was correlated with Reye's syndrome.

Amino Acids↗