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Biomedical subjects

M Miyaji

Publications and source records attributed to M Miyaji.

At least 163 records · Page 9Linked to original sources
PubMed1991

Antifungal activity of murine polymorphonuclear neutrophils against Histoplasma capsulatum.

Murine polymorphonuclear neutrophils (PMN) were examined for fungicidal and fungistatic activity against yeast cells of Histoplasma capsulatum. In a 16-h limiting dilution assay (LDA) (constant number of PMN versus decreasing numbers of yeast cells) where PMN to yeast cell ratios were high (0.4-1.5 x 10(5):1), murine PMN exhibited a limited fungicidal effect on H. capsulatum as measured by sterilization of cultures containing one to four yeast cells. On the other hand, inoculum colony forming units (c.f.u.) of H. capsulatum were not reduced by PMN in short-term (2 h) assays (PMN to yeast cell ratio, 500:1) even though H. capsulatum stimulated a brisk oxidative burst in PMN. In the same assays 84% of Candida albicans cells were killed. These findings indicate that H. capsulatum was resistant to killing by products of the oxidative burst generated by PMN and that it was slightly sensitive to PMN in 16-h LDA assays where a different microbicidal mechanism may be operative. In long-term co-culture assays, where the PMN to yeast cell ratio was 500:1, PMN consistently inhibited the replication of H. capsulatum after 24, 48, or 72 h of incubation. Inoculum c.f.u. failed to increase significantly in co-cultures, whereas in culture medium alone c.f.u. increased several-fold in 72 h. Based on these novel findings, we speculate that PMN might play a role in resistance to H. capsulatum due to their strong fungistatic activity and to a lesser extent their limited fungicidal action.

Animals↗
PubMed1990

Mitochondrial DNA analysis of Exophiala jeanselmei and Exophiala dermatitidis.

Mitochondrial DNA (mtDNA) analysis with Hae III, Hind III and Msp I was performed in 45 Exophiala jeanselmei strains (30 Phialophora jeanselmei and 154 Phialophora gougerotii strains) and 31 Exophiala dermatitidis strains. The results were as follows, 1) P. jeanselmei and P. gougerotii are identical, 2) E. jeanselmei is classified into 18 types based on restriction profiles, 3) two strains of E. jeanselmei CBS 577.76 and CBS 578.76 are identified as E. dermatitidis, 4) E. dermatitidis has no intraspecific variation and is definitely distinct from E. jeanselmei, 5) E. jeanselmei is suggested to be a complex organism because of extensive mtDNA polymorphism.

DNA, Fungal↗
PubMed1990

The role of microfilaments and microtubules in apical growth and dimorphism of Candida albicans.

Cytoskeleton inhibitors were used to study morphogenesis in the pathogenic and dimorphic fungus Candida albicans. Nocodazole is a specific microtubule inhibitor and chloropropham (CIPC), at high concentrations, is an inhibitor of microtubules and microfilaments. Distribution of microtubules and microfilaments was studied by immunofluorescence techniques using anti-tubulin antibody with FITC-conjugated secondary antibody, and by staining with Rh-phalloidin. Nocodazole did not arrest apical cell elongation at a concentration (20 micrograms ml-1) that inhibited nuclear division and migration. Cytoplasmic and nuclear microtubules disappeared within 30 min in filamentous cells under these conditions. However, the Rh-phalloidin-stained actin granules which were localized in the tips of filamentous cells, and the microfilaments, were arranged normally at this concentration of nocodazole. Growth, and normal distribution of microtubules and microfilaments, were inhibited by a high concentration (200 micrograms ml-1) of CIPC. At a concentration (100 micrograms ml-1) of CIPC that permitted nuclear division, apical cell elongation was arrested, and filamentous growth was converted into yeast growth. At this concentration of CIPC, microtubules were distributed normally in filamentous cells. Long microfilaments were not observed, and actin granules did not localize in the tips of filamentous cells, but were distributed throughout the cytoplasmic cortex. Our results show that cytoplasmic microtubules are not essential for the elongation of filamentous cell tips but that microfilaments are apparently essential for this process.

Actin Cytoskeleton↗
PubMed1990

Comparative sequential changes in serum and biliary levels of bile acid components after a single dose of D-galactosamine or partial hepatectomy in the rat.

In order to characterize changes in bile acid profile during liver cell damage and regeneration, levels of bile acids in serum and bile were determined by high performance liquid chromatography (HPLC) in F344 rats treated with a single dose of D-galactosamine (galactosamine, 300 mg/kg, i.p.) or subjected to two-thirds partial hepatectomy (PH). In the serum, galactosamine caused elevation of conjugated bile acids such as taurocholic acid (TCA) and tauro-beta-muricholic acid (T beta MCA) at the 24 and 48-h time points, whereas unconjugated bile acids including cholic acid (CA) at 24 h and hyodeoxycholic acid (HDCA) at 48 h were increased after PH. In the bile, elevation of TCA showed most remarkable elevation at the 24-h time point in the galactosamine-treated group. All components of biliary bile acids showed rapid decreases from 24 to 48 h. The results demonstrated that while liver tissue damaged by galactosamine is able to conjugate bile acids it allows leakage into the blood stream. In contrast, the results for rats subjected to PH indicated that liver cells during DNA synthesis are not capable of conjugating all free bile acids with taurine although a similar leakage occurs. It is concluded that obvious elevation of serum TCA or CA and biliary T beta MCA could be a useful indicator of hepatocellular proliferation.

Animals↗
PubMed1989

A case of the pathogenesis of choledochocele in relation to dysfunction of the sphincter of Oddi.

A 47-year-old woman was admitted for evaluation of pain in the right upper quadrant of the abdomen. Seventeen years previously, she had undergone cholecystectomy for cholelithiasis. Endoscopic retrograde cholangiopancreatography (ERCP) showed a cystic dilatation of the terminal portion of the common bile duct (CBD) protruding into the duodenal lumen and delaying the drainage of contrast medium. In this patient the CBD and the pancreatic duct appeared to be unimportant in the formation of the cyst. Repeated changes in the radius of the cyst suggested dysfunction of the ampullary component of the sphincter of Oddi, with maintenance of normal function of the common duct component. The pathogenesis of the choledochocele in this patient is discussed in relation to dysfunction of the sphincter of Oddi. In addition, 2 criteria for the diagnosis of choledochocele by ERCP are proposed: [1] cystic dilatation of the terminal portion of the CBD protruding into the duodenal lumen, and [2] absence of the narrow segment of the CBD.

Ampulla of Vater↗
PubMed1989

[Effect of antibiotics and anti-cancer drugs on gastrointestinal infections and dissemination by C. albicans in mice inoculated orally with C. albicans].

The authors studied the effect of antibiotics, hydrocortisone and anti-cancer drugs on gastrointestinal infections and dissemination by C. albicans in mice inoculated orally with C. albicans. The mice were given orally, vancomycin, amikacin and polymyxin B, and they also were injected with ampicillin and gentamicin. Hydrocortisone, cyclophosphamide (CPA) which causes leukopenia and neutropenia, and methotrexate (MTX) which injures the mucous membrane of the gastrointestinal tract were injected to the mice. In the mice treated with antibiotics and anti-cancer drugs, and inoculated orally with C. albicans, the colony forming units of the feces conspicuously increased. Gastrointestinal candidiasis was frequently observed, particularly at the cardia and the cardio-antrum line of the stomach of these mice. In addition to these sites, gastrointestinal candidiasis was observed at the antrum and the small intestine of the mice injected with MTX. C. albicans was frequently recovered from the livers and lungs of the mice treated with antibiotics and MTX + CPA which cause leukopenia, neutropenia and the damage of mucous membrane of the gastrointestinal tract. It is suggested that the threshold gut population of C. albicans is a determinant for gastrointestinal candidiasis, and that leukopenia, neutropenia and the damage of mucous membrane of the gastrointestinal tract are important factors for dissemination by C. albicans from the primary gastrointestinal lesions.

Administration, Oral↗
PubMed1989

NB-355: a novel prodrug for L-DOPA with reduced risk for peak-dose dyskinesias in MPTP-treated squirrel monkeys.

Prodrugs may be used to improve the absorption and bioavailability of certain active compounds. We have examined the ability of a novel catechol monoester of L-DOPA, NB-355 [L-3-(3-hydroxy-4-pivaloxyloyphenyl)alanine], to stimulate locomotor activity and induce dyskinesias in MPTP-treated primates. In the presence of carbidopa, a dose-dependent increase in locomotor activity over 4 1/2 h was observed following administration of L-DOPA (10, 20 or 40 mg/kg p.o.) or NB-355 (20, 40 or 80 mg/kg p.o. dopa equivalent). The dose-response curve for NB-355 was shifted to the right such that approximately twice the dopa equivalent dose of NB-355 was required to stimulate locomotor activity to the same level observed for L-DOPA. At doses matched for total locomotor stimulation over the 4 1/2-h period (20 mg/kg L-DOPA and 40 mg/kg NB-355), there was a more gradual rise and increase in the duration of motor stimulation by approximately 40% using NB-355. At these doses, drug-induced dyskinesias were less severe following treatment with NB-355 than with L-DOPA. Our findings suggest that NB-355 may be a useful therapeutic agent for increasing the duration of action of L-DOPA and reducing the severity of peak-dose dyskinesia.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1988

Studies on detection of Candida antigen in the sera of mice inoculated orally with Candida albicans.

The authors succeeded in establishing a murine model of systemic candidiasis being disseminated from the primary gastrointestinal lesions caused by oral inoculation of Candida albicans. Using this model, an attempt was made for detecting the Candida antigen by enzyme-linked immunosorbent assay using avidin-biotin (AB-ELISA) from the serum of infected mice. Gastrointestinal candidiasis was formed in all of the 20 mice treated with the drugs (antibiotics, antineoplastic agents, hydrocortisone, etc.) and inoculated orally with C. albicans. Fourteen of these mice suffered from submucosal candidiasis, and C. albicans was cultured from the visceral organs in 12 of them. The assay by AB-ELISA was able to detect 1.0 ng/ml Candida mannan in the mouse serum. The Candida antigen was detected in the sera of 11 of the 14 mice with submucosal candidiasis. However, the antigen could not be detected in the sera of the 6 mice with intramucosal candidiasis. The assay by AB-ELISA is more sensitive and specific for the diagnosis of systemic candidiasis than other serological assays.

Animals↗
PubMed1988

Application of flow cytometry to differentiating Exophiala dermatitidis, E. moniliae and E. jeanselmei from each other.

We applied a flow cytometry apparatus (FCM) to differentiating Exophiala dermatitidis, E. moniliae and E. jeanselmei from each other. The wavelength of the argon laser emitted from the FCM was 488 nm and the aperture of nozzle from which the stream of fluid containing single cells was blown out was 100 micron. By irradiating the stream with laser by either the forward light scatter (FLS) or by the perpendicular light scatter (PLS), we were able to get two pieces of informations. Histograms displayed by the FLS indicate the cell size, while dot displays by the PLS reflect the cell structure. As a result, E. dermatitidis was clearly differentiated from either E. moniliae or E. jeanselmei by their histograms by FLS. In addition, dot displays by the PLS differentiated E. moniliae from E. jeanselmei. In conclusion, flow cytometry is available for differentiating E. dermatitidis, E. moniliae and E. jeanselmei from each other.

Cell Differentiation↗
PubMed1988

Effect of ursodeoxycholate on the biliary excretion of cefotiam and sulbenicillin in patients with percutaneous transhepatic biliary drainage.

The effects of ursodeoxycholate administration on the biliary excretion of the antibiotics cefotiam and sulbenicillin were studied in five patients with stable hepatic function receiving percutaneous transhepatic biliary drainage for obstructive jaundice. Cefotiam (I g) and sulbenicillin (2 g) were administered intravenously before and after ursodeoxycholate administration, and the maximum concentrations of the antibiotics in the bile and total amounts excreted in the bile during the 4 h after administration were determined. After ursodeoxycholate administration, both the maximum concentration of cefotiam in the bile and the amount excreted increased significantly. Ursodeoxycholate also increased the peak concentration and total excretion of sulbenicillin. For both cefotiam and sulbenicillin, the amount of antibiotic excreted in the bile during the 4 h after administration showed a significant correlation with the amount of bile acids excreted in the bile. This strongly suggests a common mechanism for the biliary excretion of these antibiotics and bile acids. Ursodeoxycholate administration is a benign way to increase both the concentration and the total amount of antibiotic excreted in the bile. Therefore, it may be useful in the treatment of serious biliary tract infections, especially in patients receiving biliary drainage.

Aged↗
PubMed1987

Fungi in bathwater and sludge of bathroom drainpipes. 1. Frequent isolation of Exophiala species.

Samples of bathwater from 14 homes and 22 public bathhouses and sludge in drainpipes from 19 household bathrooms were plated out onto potato dextrose agar supplemented with chloramphenicol. Several media were used to study colony morphology of the isolates and the thermotolerance and alkaline tolerance of each isolate were examined. Eleven sludge samples produced 12 isolates of Exophiala jeanselmei, 2 of E. dermatitidis and 1 of E. moniliae. Five household bathwater samples produced 2 isolates of E. jeanselmei, 4 of E. dermatitidis and 1 of E. alcalophila. One isolate of E. jeanselmei, 2 of E. dermatitidis, 3 of E. moniliae and 2 of unidentified Exophiala species were recovered from 6 samples of the bathwater dissolving 'Chinese medicine' in the bathtubs of public bathhouses. One isolate of E. jeanselmei was recovered from the 15 samples of bathwater from public bathhouses. Bathwater and sludge in bathroom drainpipes may be an important habitat of Exophiala species.

Baths↗