Search PubMed⌕ Search

Biomedical subjects

M Shibata

Publications and source records attributed to M Shibata.

At least 775 records · Page 43Linked to original sources
PubMed1982

The preventive effect of human interferon-alpha on influenza infection; modification of clinical manifestations of influenza in children in a closed community.

A double-blind, controlled trial to ascertain the preventive effect of human interferon-alpha (Hu IFN-alpha) on upper respiratory viral infections was performed on children in a closed community. Drops of Hu IFN-alpha were instilled into the nasal cavity of 13 healthy children aged one to three years. Fourteen children were given placebos as controls. Administration of the interferon and clinical observations were carried out in the winter of 1980. Serological examination revealed that this was the period of outbreaks of influenza type A epidemics in the community. Clinical manifestations referable to influenza virus infection were milder in the interferon-treated group than in the controls. However, there was no significant difference in the serological responses of the two groups after infection with influenza virus type A.

Administration, Intranasal↗
PubMed1981

Role of tryptophanyl and tyrosyl residues of flavoproteins in binding with flavin coenzymes. X-ray structural studies using model complexes.

The crystal structures of 7,8-dimethylisoalloxazine-10-acetic acid-tryptamine (1:1) tetrahydrate and 7,8-dimethylisoalloxazine-10-acetic acid-tyramine (1:1) tetrahydrate complexes were determined by the X-ray diffraction method, as models for flavin-tryptophan and flavin-tyrosine interactions in flavoproteins. The observed parallel stackings and the intermolecular spacing distances, which were less than the normal van der Waals separation between the isoalloxazine and indole rings and between the isoalloxazine and phenol rings, suggest the existence of charge-transfer interactions in their ground states. The indole and phenol rings interact with the pyrimindinoid and pyrazinoid portions of the isoalloxazine ring and have short contacts, less than 3.4 A, with the reduction site (N1 and N5 atoms) of this ring. This suggests that the reduction of oxidized flavin to the semiquinone state may be facilitated by charge transfer from the former rings to the N1 and N5 atoms. Absorption difference spectra showed that both complexes associate with equimolar ratios in solution as well as in the crystalline state and that they have the same charge-transfer bands and association constants as flavin mononucleotide (FMN)-Trp and FMN-Tyr complexes, respectively. On the other hand, proton magnetic resonance spectra suggested that in solution, the stacking modes of the indole and phenol rings to the isoalloxazine ring are different from those observed in the crystal structures and both aromatic rings are stacked over the whole of the isoalloxazine ring.

Animals↗
PubMed1981

Analysis of nuclear accumulation of influenza NP antigen in von Magnus virus-infected cells.

When 1-5C-4 cells were infected with von Magnus virus derived from influenza A/RI/5+ virus by successive undiluted passages in chick embryos, virus-specific proteins were synthesized but production of infectious virus was inhibited. In these cells the synthesis of viral RNA was suppressed and the nucleoprotein (NP) antigen was found predominantly in the nucleus in contrast to standard virus-infected cells in which the antigen was distributed throughout the whole cell. The intracellular location and migration of NP were determined by isotope labeling and sucrose gradient centrifugation of subcellular fractions. In standard virus-infected cell NP polypeptide was present predominantly in the cytoplasm in the form of viral ribonucleoprotein (RNP) and intranuclear RNP was detected in reduced amounts. In contrast, in von Magnus virus-infected cells NP polypeptide was present predominantly in the nucleus in a nonassembled, soluble from and the amount of cytoplasmic RNP was considerably reduced. After short-pulse labeling NP was detected exclusively in the cytoplasm in a soluble form and after a chase a large proportion of such soluble NP was seen in the nucleus. It is suggested that a large proportion of the NP synthesized in von Magnus virus-infected cells in not assembled into cytoplasmic RNP because of the lack of available RNA and the NP migrated into the nucleus and remained there.

Antigens, Viral↗
PubMed1981

Analysis of the inhibitory effect of canavanine on the replication of influenza RI/5+ virus. II. Interaction of M protein with the plasma membrane.

When influenza A/RI/5+ virus-infected cells were incubated in medium to which 2 micrograms of canavanine (arginine analog) per ml had been added 4 hr after infection, all viral polypeptides were synthesized but the budding-like process with the appearance of extracellular virus was completely inhibited. The plasma membrane isolated from these cells contained exclusively hemagglutinin (HA), and membrane (M) protein and nucleoprotein (NP) appeared to be associated with the nucleus, in contrast to untreated cells whose plasma membrane contained abundant HA, M protein, and NP. Disruption of canavanine-treated cells by freeze-thawing generated a number of hemagglutinating membranous vesicles or fragments containing exclusively HA. By isotope labeling it was found that the M protein synthesized in the presence of canavanine, together with HA and NP, is a canavanine-substituted polypeptide. It is suggested that canavanine inhibits the formation of the mature envelope of influenza RI/5+, because of the inability of M protein to associate with the plasma membrane.

Animals↗
PubMed1981

Synthesis of selectively 3H or 14C-labeled 2-(4-(2-thienylcarbonyl)phenyl)propionic acid.

2-(4-(2-Thienylcarbonyl)phenyl)propionic acid (suprofen), an anti-inflammatory agent, was labeled with tritium or carbon-14 for the purpose of investigating its metabolic fate in animals. The selectively tritiated suprofen (26.3-32.1 GBq (710-867 mCi)/mmol) was obtained by catalytic dehalogenation of the brominated precursor with 185-370 GBq (5-10 Ci) of tritium gas. The labeled position of the suprofen was confirmed by spectral data of the deuterated suprofen similarly synthesized. On the other hand, suprofen-14C (48.8 MBq (1.4 mCi)/mmol) was obtained by five-step synthesis from toluene [methyl-14C] in a 19% yield.

Anti-Inflammatory Agents↗
PubMed1981

Synthesis of optically active 2-(4-(2-thienylcarbonyl)-phenyl)propionic acid labeled with deuterium.

2-(4-(2-Thienylcarbonyl)phenyl)propionic acid (suprofen), an anti-inflammatory agent, was labeled with multiple-deuterium for the purpose of investigating the metabolism in man and animals by the ion cluster technique. Racemic suprofen-d4 was prepared by ten-stop synthesis from bromobenzene-d5 in a 32% yield, and its deuterium content was 99 atom%. This racemic suprofen-d4 was resolved by use of an optically active alpha-methylbenzylamine, resulting that optically active suprofen-d4 was obtained in a 11% yield and was 96.5 atom% D. On the other hand, suprofen-d7 (99 atom% D) was obtained by five-step synthesis from toulene-d8 and methyl-d3 iodide in a 24% yield.

Anti-Inflammatory Agents↗
PubMed1981

Stimulation of the extension of validamycin-inhibited hyphae by the hyphal extension factor present in Rhizoctonia solani.

Validamycin inhibited the hyphal extension of Rhizoctonia solani without growth inhibition. Hyphal inhibition was more pronounced in the main hyphae than in the primary or secondary branches of R. solani. Validamycin inhibition was antagonized by the hyphal extract of R. solani which stimulated hyphal extension. From the hyphal extract, the hyphal extension factor antagonizing the action of validamycin was isolated as a syrup after passing through an Amberlite IR-120 B column, adsorption on an Amberlite IRA-410 column, elution with 0.2 N NH4Cl and concentration of the eluate. The hyphal extension factor stimulated only the extension of the validamycin-inhibited hyphae and not that of the normal hyphae.

Antifungal Agents↗
PubMed1981

Tumors of the anal region induced in mice painted with methylazoxymethanol acetate.

The carcinogenicity of methylazoxymethanol acetate (MAM acetate) was examined in 91 BALB/c mice by painting it on the anal region. Carcinomas and adenomas of the perianal sebaceous gland were induced in 23 of 24 male (96%) and 16 of 30 female (53%) mice and keratoacanthoma developed in one of 24 male mice within 30 weeks after treatment with MAM acetate. Vascular tumors of the liver and fat issue of the abdominal cavity also developed in 16 of 24 male (67%) and 3 of 30 female (10%) mice treated with this drug. Microscopic adenocarcinomas were found in the rectal mucosa of 3 of 24 male mice adjacent to the anorectal junction. The sex difference in the incidence of tumors is briefly discussed.

Adenoma↗
PubMed1980

Effect of calcium removal on thermosensitivity of preoptic neurons in hypothalamic slices.

Extracellular single-unit activities of thermosensitive neurons were recorded from the medial preoptic area in rat's hypothalamic slices in vitro. Of 256 preoptic units, 74 were warm-units which increased firing rates in response to a rise in slice temperature and 16 units were cold-units having the opposite type of thermosensitivity. Eighteen of 23 warm-units and 3 of 4 cold-units retained their thermosensitivities during perfusion with Ca2+-free/high Mg2+ salt solution. The thermosensitivities of the remaining 5 warm-units were reversibly abolished in the Ca2+ deficient medium. The results suggest that some warm- and cold-sensitive neurons in the medial preoptic area have an inherent thermosensitivity.

Animals↗
PubMed1980

Glycosidase activities in the liver and kidney of hereditary diabetic mice.

Hereditary diabetic mice (NSY) were inbred from original streptozotocin diabetic ICR mice for 8-9 generations using hyperglycemia as an index. The normoglycemic ICR mice were used as controls for the NSY line. The nonfasting blood sugar level of the NSY mice was 305 +/- 14 mg/100ml, while their immunoreactive insulin level was 30 +/- 4 microU/ml (the values of the controls were 165 +/- 12 mg/100 ml and 79 +/- 14 microU/ml, respectively). beta-N-Acetylglucosaminidase [EC 3.2.1.29], beta-galactosidase [EC 3.2.1.23], alpha-glucosidase [EC 3.2.1.21], and alpha-mannosidase [EC 3.2.1.24] activities were determined in the 1,000 X g supernatant of the liver and the kidney of control and streptozotocin diabetic ICR mice and their NSY line. In the kidneys of the insulinopenic NSY mice, the beta-galactosidase and alpha-mannosidase activities were significantly decreased. No significant changes were found in liver enzyme activities. Insulin treatment increased the kidney beta-galactosidase activity signficantly. The insulinopenic state, which caused a decrease in the glycosidase activities in the kidney, could induce retarded breakdown of glycoprotein.

Animals↗