Search PubMed⌕ Search

Biomedical subjects

Y Kawamoto

Publications and source records attributed to Y Kawamoto.

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

Complement proteins and macrophages. III. The production of factor B by particle-ingesting macrophages.

A kinetic study of factor B secretion by particle-ingesting macrophages showed that the ingestion of zymosan but not latex lead to an early suppression of factor B secretion followed by a significant enhancement. This dual response was proportional to the number of ingested zymosans. After a suppressive period of 24-48 hr, the ingested zymosan stimulated the synthesis of factor B. The response of acid phosphatase synthesis to ingested zymosan was the same as that of factor B, while the synthesis of lactic dehydrogenase proceeded without an early suppression. These results suggest that factor B should be considered an enzyme released into the lysosomes of macrophages.

Acid Phosphatase↗
PubMed1981

Partial purification and characterization of heat-stable enterotoxin produced by Yersinia enterocolitica.

By using a suckling mouse assay, heat-stable enterotoxin (ST) was purified from the culture filtrate of Yersinia enterocolitica isolated from a diarrheal patient. The purification procedures involve ultrafiltration with an Amicon HIP-10 hollow fiber, ethanol fractionation, protamine sulfate treatment, diethylaminoethyl-Sephacel and hydroxylapatite column chromatographies, and Sephacryl S-200 superfine gel filtration. About 408-fold purification was achieved, with a yield of 12.0%. The minimal effective dose of purified ST was about 110 ng in the suckling mouse assay. The molecular weight of purified ST was 9,000 by Sephadex G-100 superfine gel filtration. The purified ST was stable to heating (100 degrees C for 20 min, 121 degrees C for 20 min) and did not lose its toxicity after treatment with protease, trypsin, lipase, phospholipase C, ribonuclease, deoxyribonuclease, beta-glucosidase, and neuraminidase. The purified ST was separated by isoelectric focusing into two active fractions, with pI's of 3.29 (ST-1) and 3.00 (ST-2), respectively. Antiserum from guinea pigs immunized with the purified ST neutralized the activity of both Y. enterocolitica ST and Escherichia coli ST.

Bacterial Toxins↗
PubMed1980

Heat-stable enterotoxin produced by Yersinia enterocolitica isolated from patients.

Twenty-three strains of Yersinia enterocolitica were isolated from children with gastrointestinal illness and examined for the production of enterotoxins by using both suckling mouse and Chinese hamster ovary (CHO) cell assay systems. Six strains were found to be enterotoxigenic in the suckling mouse assay, but all strains were negative in the CHO cell assay. Enterotoxin was detected in the culture supernatant when organisms were grown at 25 C but not at 37 C. Enterotoxin in a 15-fold concentrated culture supernatant was precipitated by adding absolute ethanol to a concentration of 90%. However, after being dialyzed against distilled water in Spectra/por 6 membrane tubing, it was soluble in 80% acetone. One unit dose of partially purified enterotoxin was 5.0 micrograms of protein/mouse in the suckling mouse assay. The molecular weight of enterotoxin was between 10,000 and 50,000 daltons as determined by ultrafiltration. It was stable to heat (121 C X 20 min or 100 C X 60 min). These observations indicated that Y. enterocolitica isolated in Japan also produce an enterotoxin similar to the heat-stable enterotoxin of Escherichia coli. However its physiochemical properties seem to be different from those of E. coli.

Child↗
PubMed1980

Adherence of Yersinia enterocolitica to mammalian epithelial cell lines.

Yersinia enterocolitica RIMD 2501003 grown at 25 C avidly adhered to various kinds of cultured epithelial cell lines (HeLa, FL, Y-1 adrenal, human intestine, human conjunctiva) but the bacteria grown at 37 C did not adhere. This phenomenon paralleled the temperature-dependent motility of the bacteria. To clarify the adherence mechanism, we obtained two kinds of mutants, an immobile mutant and a nonadherent mutant, by treatment with N-methyl-N'-nitro-N-nitrosoguanidine. The immobile mutant did not move on soft agar but retained the capacity to adhere to cultured epithelial cells when grown at 25 C. The nonadherent mutant did not adhere to cultured epithelial cells but retained the ability to move on soft agar when grown at 25 C. When the bacteria were killed by heat, ultraviolet light irradiation or formaldehyde they lost their capacity to adhere to the cultured epithelial cells. Antiserum against Y. enterocolitica RIMD 2501003 grown at 25 C was absorbed with the bacteria grown at 37 C, with the bacteria grown at 25 C, with the nonadherent mutant grown at 25 C and with the bacteria killed by various means. Only the antiserum absorbed with bacteria grown at 37 C inhibited the adherence of bacteria. These data indicate that motility does not correlate with adherence of Y. enterocolitica. It appears that the adherence factor involves both a temperature-dependent surface factor and a factor synthesized de novo during the interaction of susceptible cells with the bacteria.

Adhesiveness↗
PubMed1980

Complement proteins and macrophages. II. The secretion of factor B by lipopolysaccharide-stimulated macrophages.

The secretion of factor B by mouse peritoneal macrophages was found to be enhanced following in vivo or in vitro stimulation with lipopolysaccharide (LPS). The intravenous administration of LPS to mice of various strains caused an increased release of factor B but not the release of acid phosphatase by the peritoneal macrophages obtained from the stimulated mice. In vitro stimulation of cultured macrophages with LPS resulted in an enhanced secretion of both factor B and acid phosphatase. The dose-dependent augmentation of factor B secretion by LPS was found in the macrophages from LPS-responsive C3H/HeN mice, whereas the macrophages from LPS-unresponsive C3H/HeJ mice did not respond to either phenol-extracted LPS or butanol-extracted LPS. The ability of LPS to cause the enhancement of factor B secretion by macrophages was abolished by alkali or acid treatment of LPS, indicating that its lipid A part was responsible for the observed effect.

Acetates↗
PubMed1979

Complement proteins and macrophages. 1. Quantitative estimation of factor B produced by mouse peritoneal macrophages.

Cobra venom factor was used for the detection of factor B synthesized by mouse peritoneal macrophages. This method was shown to be specific for factor B assay by neutralization by antimouse factor B antibody. The amount of factor B in the culture supernatant, assessed by this method, was found to be dependent on the medium used for cultivation of macrophages. The addition of 25% L cell-conditioned medium to minimal essential medium (LCM-MEM) enhanced the production of factor B and also of lysozyme. Kinetic analysis in LCM-MEM showed that factor B produced by 6 x 10(4) cells/cm2 increased up to 72 hr and reached a plateau at 96 hr. The amounts of factor B and lysozyme produced in LCM-MEM depended upon the number of macrophages. Production of factor B was completely inhibited by 1 microgram of cycloheximide per ml and was restored by its removal.

Animals↗
PubMed1977

Intracellular development of membrane protein of influenza virus.

The intracellular development of membrane protein (MP) of influenza A virus was investigated by immunofluorescent staining. Monospecific antiserum was prepared by immunizing rabbits with MP eluted from SDS-polyacrylamide gels of SDS-disrupted NWS virions. In the productive infection in clone 1-5C-4 cells, MP antigen was first detected over the whole cell at 4 hr after infection, concomitantly with the appearance of hemagglutinin (HA) antigen in the cytoplasm, and bright nuclear fluorescence was then observed. Nucleoprotein (NP) antigen was detected in the nucleus prior to the appearance of fluorescence of MP antigen and thereafter the cytoplasmic fluorescence developed. Late in infection, all of these three antigens were observed predominantly in the cytoplasm with stronger fluorescence at the cell surface. Essentially similar findings were obtained in the abortive infections in L cells and BHK cells. The above results suggest that the membrane protein of influenza A virus is present in the nucleus as well as in the cytoplasm of infected cells.

Cell Line↗
PubMedDate not supplied

Rheological approach to the analysis of blood coagulation in endothelial cell-coated tubes: activation of the intrinsic reaction on the erythrocyte surface.

Coagulation of blood in cultured endothelial cell-coated tubes was examined using a rheological technique. Coagulation of recalcified, platelet-free plasma in contact with an endothelial cell monolayer did not occur within the experimental time period (more than 150 min). The endothelial cell surface did not activate the intrinsic coagulation reaction or the extrinsic coagulation reaction initiated by tissue factor. The time of onset of coagulation in platelet-free plasma supplemented with erythrocytes was nearly the same as that of whole blood (31.2 +/- 5.5 min), which was shorter than that for platelet-rich plasma (54.3 +/- 14.3 min) and platelet-free plasma supplemented with granulocytes (58.3 +/- 6.3 min). In factor VII-, XI- or XII-deficient, platelet-free plasma supplemented with erythrocytes, the time of onset of coagulation was about 30 min. The coagulation of factor IX-deficient, platelet-free plasma supplemented with erythrocytes, however, did not occur within the experimental time period. These data suggest that activation of factor IX on the erythrocyte surface is capable of activating the intrinsic coagulation system.

Adult↗
PubMedDate not supplied

The major component of Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of murine intraepithelial lymphocytes is granzyme A.

Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of intraepithelial lymphocytes in the murine intestine (iIEL) were characterized. BLT-specific proteases were isolated with the Sephacryl S-200 column chromatography, and the sample isolated contained a protein with a molecular weight of 58 kDa. The 58 kDa protein consisted of the homodimer of the 30 kDa subunits. The 58 kDa protease was detected by [3H] diisopropylfluorophosphate (DFP)-labeling, and also detectable by the immunoblotting using an antibody against the partial synthetic peptide of granzyme A. The cytoplasmic granules of iIEL were stained positively by an immunofluorescence with anti-granzyme A antibody. Therefore, it was suggested that the major BLT-specific proteases present in cytoplasmic granules of iIEL might be granzyme A.

Animals↗
PubMedDate not supplied

Ictal video-EEG analysis of infantile neuroaxonal dystrophy.

A 4-year-old boy with infantile neuroaxonal dystrophy (INAD) showed gradual deterioration from age 9 months with seizure development at age approximately 36 months. Sural nerve biopsy performed at age 42 months confirmed INAD. The seizure, recorded by video-EEG, consisted of a series of symmetrical tonic spasms of both upper extremities after a prodrome period of staring and akinesis. Each spasm had phonation, and episodic autonomic symptoms such as hypertension and flushing of the face occurred throughout the seizure. Ictal EEG with each tonic spasm, showed diffuse 1-s, irregular sharp and high-voltage slow wave complexes followed by desynchronization.

Axons↗
PubMedDate not supplied

Expression of the endocytosis regulatory proteins Rab5 and Rabaptin-5 in glial cytoplasmic inclusions from brains with multiple system atrophy.

BACKGROUND: Glial cytoplasmic inclusions (GCIs) occur specifically in oligodendrocytes in brains with multiple system atrophy (MSA). Oligodendrocytes in MSA appear to be functionally altered in their nature in terms of the occurrence of GCIs and aberrant expression of various proteins such as neuron specific protein, MAP2 or pre-synaptic protein, ct-synuclein. The present study examined whether or not aberrant expression of the endocytosis regulatory proteins Rab5 and Rabaptin-5 occcur in oligodendrocytes of brains with MSA. MATERIALS AND METHODS: We examined immunohistochemically the post-mortem brain tissues from 5 patients with MSA and 5 controls. Immunohistochemistry was done using monoclonal anti-Rab5 and anti-Rabaptin-5 antibodies based on ABC method. RESULTS: We have observed Rab5 and Rabaptin-5 immunoreactivity in the neuronal somata and axons of the controls, suggesting that Rab5 and Rabaptin-5 are involved in the regulation of the endocytosis in neurons of the human central nervous system. In the brain tissues from patients with MSA, we have found Rab5 and Rabaptin-5 immunoreactivity in GCIs. CONCLUSION: Rab5, in association with Rabaptin-5, has been demonstrated in the early endosome and regulates the endocytosis. Since Rab5 and Rabaptin-5 have been immunolocalized to neurons in the human brains, we propose that oligodendrocytes may ectopically express Rab5 and Rabaptin-5 in MSA. Thus, the oligodendrocytes in MSA brains appear to be functionally significantly altered, which may be associated with the formation of GCIs in the oligodendrocytes.

Aged↗