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Biomedical subjects

M Iwanaga

Publications and source records attributed to M Iwanaga.

At least 109 records · Page 6Linked to original sources
PubMed1990

Vibrio cholerae serogroup O1 in northeast Thailand.

Strains of Vibrio cholerae serogroup O1 biotype El Tor that are susceptible to Mukerjee cholera bacteriophage group IV (S. Mukerjee, Bull. W.H.O. 28:333-336, 1963) were found. Cholera vibrios isolated from epidemics in northeast Thailand were characterized, and 57 of 60 strains isolated in 1986 were susceptible to cholera phage IV. However, all 113 strains isolated in 1988 were not susceptible to the phage. All isolates in both epidemics revealed behaviors typical of El Tor vibrios, except phage IV susceptibility in the 57 strains. Although the plaques of phage IV were generally translucent, plaques on some isolates looked transparent, just like those on classical vibrios. The organisms grown in the plaques were lysogenized. If this kind of strain is frequently isolated, the biotype of V. cholerae O1 should be reconsidered.

Bacterial Typing Techniques↗
PubMed1990

Simultaneous determination of GTP cyclohydrolase activity and biopterin content in pheochromocytoma PC12h cells.

A method to measure the GTP cyclohydrolase and biopterin (BP) content at the same time in the sonicate of pheochromocytoma PC12h cells was described. The cells cultured in a 5-cm dish were sonicated with 0.4 to 0.5 ml of 50 mM Tris-HCl, pH 7.8, and a 50 microliters aliquot was used for one assay. After the GTP cyclohydrolase reaction, dihydroneopterin triphosphate, the reaction product, was oxidized and dephosphorylated to form neopterin (NP); and the pterins in the reaction mixture were then analyzed by high-performance liquid chromatography (HPLC). Mainly three peaks of pterins were detected in the eluate from the HPLC column: they were NP, BP, and 2-amino-4-hydroxypteridine (AHP). The amount of NP was a measure of the enzyme activity. On the other hand, a significant part of the biopterin contained in the enzyme sample was converted to AHP during the GTP cyclohydrolase reaction. Therefore, the sum amount of BP plus AHP was a measure of total BP content in the enzyme sample (sonicate of PC12h cells). The method is convenient and useful to study the actions and action mechanisms of various biologically active substances on the BP level of pheochromocytoma cells in culture.

Animals↗
PubMed1989

Pili of Vibrio cholerae O1 biotype E1 Tor: a comparative study on adhesive and non-adhesive strains.

Pili were found on the cell surface of non-adhesive Vibrio cholerae O1 Biotype E1 Tor as well as the adhesive strain. Purified pili of the adhesive and non-adhesive strains were morphologically, electrophoretically, and immunologically, indistinguishable from each other. The molecular weights of both pilin (subunit protein of the pilus) were about 16,000 daltons as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These 16 kDa pili are different from the pilus colonization factor, which is a 20.5 kDa protein, reported by Taylor et al. The 16 kDa pili of Vibrio cholerae O1 Biotype E1 Tor have hemagglutinating activity, but may have no role in colonization, because non-adhesive strains also have such pili.

Animals↗
PubMed1989

Hemolytic Vibrio cholerae O1 that is sensitive to Mukerjee's cholera phage IV and the phage produced by the hemolytic vibrio lysogenized with the infection of Mukerjee's cholera phage IV.

Strains of hemolytic Vibrio cholerae O1 (El Tor vibrio) which are sensitive to Mukerjee's cholera phage group IV were isolated from cholera patients in North-East Thailand in 1986. Plaques of the phage on these hemolytic V. cholerae O1 were usually translucent but almost transparent on some strains, just like the plaques on non-hemolytic V. cholerae O1 (classical vibrio). These hemolytic V. cholerae O1 were lysogenized with the infection of cholera phage IV, and the lysogenized strains produced phage different from cholera phage IV. These hemolytic strains were classified into Cured type in prophage typing of V. cholerae O1, El Tor, because they were also lysogenized with Kappa phage and were hemolytic. When Cured-type V. cholerae O1, El Tor previously isolated in various countries were examined for the sensitivity to cholera phage IV, some of the isolates were sensitive.

Bacteriophages↗
PubMed1989

[The effect of local injection of interferon against human malignant glioma transplanted into nude mice and the mechanism of its effect].

In order to clarify the mechanism of action of recombinant human leucocyte interferon, the effect of local injection of it to the human malignant gliomas (one oligodendroglioma, the other glioblastoma) transplanted into nude mice were evaluated. The volume of the tumors were calculated as 1/2 (short diameter [cm])2 x (long diameter[cm]). And the ratio of tumor volume (T)/original size (C) were calculated in terms of experimental day. Among the groups of control (vehicle of IFN injected), 1 million units of IFN locally injected group, 3 million units injected group, and 9 million units injected group, the effects of the treatment were statistically evaluated in terms of T/C. At the end of the experiment, each animal was injected 4 mg of BrdU intraperitoneally, and the labeling indices of the tumor tissue were measured and compared among the groups above mentioned. Local injection of IFN to the tumor was effective even at the dose of 1 million units every other day for 16 days for glioblastoma and 50 days for oligodendroglioma. The labeling index of the treated groups was significantly reduced when compared to that of control group in both tumors. And the experiment was performed to evaluate the variation of NK activity and ADCC activity of mouse spleen cells among the experimental groups. For the oligodendroglioma, NK activities were significantly increased in the 9 million units of IFN injected group when compared to those of control group. For glioblastoma, there was no definite variation of NK and ADCC activities among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Prolonged retention of a swallowed foreign body in the stomach following pyloromyotomy.

An unusual case of prolonged retention of a swallowed, round-shaped, magnet tack in the stomach of a patient is reported. The patient had had a previous pyloromyotomy for pyloric stenosis. Patients with a history of pyloromyotomy for pyloric stenosis may present special problems for the passage of foreign bodies reaching the stomach and may be more likely to require surgical intervention.

Foreign Bodies↗
PubMed1988

Vibrio cholerae O1 adherence to villi and lymphoid follicle epithelium: in vitro model using formalin-treated human small intestine and correlation between adherence and cell-associated hemagglutinin levels.

Formalin-fixed human small intestinal mucosa possessing villi and lymphoid follicle epithelium of Peyer's patches at the mucosal surface was used to test the adherence ability of clinically isolated strains of Vibrio cholerae O1. V. cholerae O1 grown on CFA agar for approximately 3 h at 37 degrees C had various levels of cellular hemagglutinins (HAs) and manifested adherence abilities that were roughly correlated with the cellular HA levels, irrespective of cellular HA types. V. cholerae O1 adhered better to epithelium over ileal lymphoid follicles than to epithelium of jejunal or ileal villi. Cells of different morphology which constituted lymphoid follicle epithelium were almost equal targets for adherence. In contrast, V. cholerae O1 grown on CFA agar for approximately 20 h at 37 degrees C in many cases had lower levels of cellular HAs and adherence abilities. Contrary to the above observations with cellular HAs and adherence, piliation of V. cholerae O1 was rather more extensive at approximately 20 h of incubation at 37 degrees C than at approximately 3 h of incubation at 37 degrees C. L-Fucose inhibited adherence to a varied extent depending on the cellular HA types, while D-mannose enhanced adherence in some strains. Heating of V. cholerae O1 diminished adherence ability. This adherence model system provides a tool by which various V. cholerae O1 strains can be preliminarily tested for adherence ability and site in human small intestine.

Animals↗
PubMed1988

Histologic study of homograft cartilages implanted in the middle ear.

We examined conditions of the micro-sliced homograft cartilages implanted in the middle ear, implanted cartilages removed at revision surgery or implanted cartilages removed at the second stage of staged tympanoplasty, both macroscopically and histologically. Macroscopically, the appearance and shape of the cartilages remained unchanged, with no evidence of erosion. There was no evidence of any foreign body reaction or rejection phenomenon. In general, no marked histologic changes of the matrix tissues were found, although chondrocytes showed degenerative changes. There was partial absorption of cartilage and replacement by fibrous connective tissue when inflammatory changes occurred in the middle ear. It is concluded that implanted homograft cartilage maintains its stiffness for more than 6 months in a healthy, aerated middle ear and appears to be clinically useful for tympanoplasty.

Cartilage↗
PubMed1987

Demonstration of GM1-ganglioside in nervous system in generalized GM1-gangliosidosis using cholera toxin B subunit.

By using cholera toxin B subunit and its antibody, the deposition of GM1-ganglioside in the cerebral cortex and peripheral nerves including Meissner and Auerbach's plexuses in the intestine and other visceral nerves of generalized GM1-gangliosidosis was demonstrated. The GM1-ganglioside was found in the swollen neurons of cerebral cortex and ganglion cells of the peripheral nerves. Electron microscopically, parts of membranous cytoplasmic bodies, and amorphous substances among them, revealed a positive reaction for the cholera toxin staining.

Cerebral Cortex↗
PubMed1987

Characterization of Vibrio cholerae 01 recently isolated in Bangladesh.

91 strains of Vibrio cholerae O1, isolated in Bangladesh in January 1986, were examined for their biological behaviour and sensitivity to 6 antimicrobial agents. Biotyping indicated that 60 of the isolates belonged to the classical biotype and 31 to the El Tor biotype. 21 El Tor strains revealed beta-haemolysis on blood agar plates, but only 8 showed complete haemolysis in broth. Serotyping indicated 79 Ogawa, 10 Inaba, and 2 Hikojima. Phage typing showed that all classical vibrios belonged to Mukerjee's phage type 1. El Tor vibrios were classified into 4 groups: one strain each in type 1 and type 5, 19 in type 4, and 10 in an untypable group. Prophage typing of El Tor vibrios identified 14 strains of Ubol type, 16 of cured Celebes type, and one of original Celebes type. No strain was resistant to tetracycline, minocycline, chloramphenicol, streptomycin, amoxicillin or nalidixic acid. The classical vibrios differed from those isolated before 1973 in toxin production pattern.

Animals↗
PubMed1987

Purification and partial characterization of fimbriae of Vibrio cholerae O1.

Fimbriae of Vibrio cholerae O1 were purified from a strain of the classical biotype, Inaba serotype (Bgd 17), and a strain of the El Tor biotype, Ogawa serotype (K23), grown on TCG agar medium by the following procedure; homogenization of the cell suspension to detach fimbriae, ultracentrifugation to remove remaining cells and their debris, concentration of the supernatant containing fimbriae with ultrafiltration, and 20 to 40% sucrose linear gradient centrifugation of the concentrated material. The fimbriae in both preparations were flexible, long fibres readily distinguishable under the electron microscope from those of CFA/I, CFA/II seen in ETEC strains. Their structural subunit was a protein of 16 kdaltons. Fimbriae isolated from both serotypes and biotypes shared antigenic determinants.

Antigens, Bacterial↗
PubMed1987

Impaired polymorphonuclear leukocyte function in biliary atresia: role of bilirubin and bile acids.

Our previous study suggested that impaired bactericidal activity of polymorphonuclear leukocytes in patients with biliary atresia might be due to decrease in superoxide-generating activity and that serum factors may play an important role. In the present study, analysis of the patients' serum revealed that, among 15 bile acids, glycine or taurine conjugated chenodeoxycholic acid and cholic acid were markedly elevated. To examine the effects of bilirubin and these bile acids and conjugated lithocholic acids on the leukocyte function, we measured cytolysis, phorbol myristate acetate-induced superoxide generation, and myeloperoxidase activity, using normal human polymorphonuclear leukocytes. Bilirubin ranging from 5 to 20 mumol/L was cytolytic and more potently inhibited the superoxide generation. The inhibition by bilirubin was also observed in the presence of 10% human serum or 2.0% human serum albumin, though the cell viability was almost completely preserved. On the other hand, conjugated chenodeoxycholic acids and cholic acids, ranging from 0.5 to 1.5 mmol/L or conjugated lithocholic acids, ranging from 0.02 to 0.05 mmol/L, did not inhibit the superoxide generating activity, though the conjugated chenodeoxycholic acids and lithocholic acids did induce cytolysis. Myeloperoxidase activity was little affected, except in the case of conjugated lithocholic acids. These results suggest that in patients with biliary atresia, bilirubin, probably the unconjugated form, more than bile acids might be one of the influential factors in the suppression of bactericidal activity of polymorphonuclear leukocytes, by inhibiting the superoxide-generating activity.

Bile Acids and Salts↗
PubMed1987

Soft tissue reaction to ceramic ossicular replacement prosthesis.

Soft-tissue reaction to ceramic ossicular replacement prostheses (CORP) has been evaluated histologically in rabbits and humans. One week after implantation, severe inflammatory and foreign body reaction was observed in the fibrous connective tissue surrounding the prosthesis. Though some inflammatory response was seen after one month, after three months the CORP was surrounded by a layer of fibrous connective tissue without any foreign body giant cell, histiocyte or inflammatory cell infiltration. Our satisfactory clinical results in humans without placing a cartilage between the CORP and the fascia graft may be due to the excellent soft-tissue compatibility of CORP, as demonstrated in this study.

Aluminum↗
PubMed1987

Quantitative evaluation of colonizing ability of Vibrio cholerae O1.

A new method to evaluate the adhesive ability of Vibrio cholerae O1 was proposed. Broth cultured V. cholerae O1 and a piece of formalin-fixed rabbit intestinal wall were incubated together in KRT buffer and the number of adhered organisms was counted under a scanning electron microscope. This method was much less laborious than other methods that have been used so far, and most significantly, constant results were obtained in repeated experiments. The adhesive properties of toxigenic V. cholerae O1 evaluated by this method correlated well with its observed experimental pathogenicity.

Animals↗