Biomedical subjects

M Miyaji

Publications and source records attributed to M Miyaji.

At least 145 records · Page 8Linked to original sources

PubMed1992

A basis for resistance of Blastomyces dermatitidis killing by human neutrophils: inefficient generation of myeloperoxidase system products.

The mechanism by which the yeast form of Blastomyces dermatitidis resists killing by human peripheral blood polymorphonuclear neutrophils (PMN) was investigated. The metabolic products of the oxidative burst generated during the interaction of PMN and B. dermatitidis or Candida albicans were detected by lucigenin- or luminol-enhanced chemiluminescence (CL). Interaction of PMN and C. albicans resulted in luminol-enhanced CL 100-fold greater than that generated by PMN and B. dermatitidis. This correlated with killing of C. albicans and resistance of B. dermatitidis. Since B. dermatitidis and PMN interactions resulted in significant lucigenin-enhanced CL, deficient luminol CL was not due to a lack of products from the NADPH oxidase system. Killed B. dermatitidis cells at 37 degrees C were more efficient than live cells in stimulating PMN for luminol-enhanced CL; however, only fragmented B. dermatitidis cells elicited luminol-enhanced CL equivalent to that of C. albicans. Since lysates of PMN were active in a cell-free hydrogen peroxide-peroxidase-halide system, resistance of B. dermatitidis to PMN was not due to a defect in PMN peroxidase. Taken together, these findings indicate that resistance of B. dermatitidis to killing by PMN results from inefficient generation of products from the peroxidase-dependent PMN microbicidal system.

Acridines↗

PubMed1992

The postantifungal effect of 5-fluorocytosine on Candida albicans.

The in-vitro postantifungal effect (PAFE) of 5-fluorocytosine for Candida albicans for short periods of time was investigated. Yeast cells were exposed for 0.5, 1 or 2 h to a range of concentrations (0.1-3.2 mg/L) of 5-fluorocytosine. The PAFE was quantitated by determinations of the number of colony forming units at hourly intervals (0-10 h) after removal of the drug by dilution. The length of the PAFE was dependent upon the concentration of 5-fluorocytosine and the duration of exposure. An exposure time of 0.5 h resulted in PAFE's ranging from 0 to 4.2 h. Exposure times of 1 and 2 h resulted in longer PAFEs and in many instances suppression of cell growth was seen for the entire evaluation period (up to ten hours).

Candida albicans↗

PubMed1992

In-vitro activity of new carbapenem antibiotics: comparative studies with meropenem, L-627 and imipenem against pathogenic Nocardia spp.

MICs of two new carbapenems, meropenem and L-627, and imipenem were determined against 98 strains of the Nocardia asteroides group (i.e. N. asteroides sensu stricto, Nocardia farcinica and Nocardia nova), 46 strains of Nocardia brasiliensis and 17 strains of Nocardia otitidiscaviarum. Meropenem and L-627 were less active against the N. asteroides group than imipenem. Among the three species of the N. asteroides group, N. nova was the most sensitive to all the carbapenems. Meropenem was more active than imipenem against both N. brasiliensis and N. otitidiscaviarum with MIC50 values of 28.3-53.3 mg/L. L-627 was less active than meropenem.

Carbapenems↗

PubMed1992

[Studies on the effect of combination of amphotericin B and flucytosine on Candida albicans by flow cytometry].

The antifungal effects of amphotericin B (AMPH) and flucytosine (5-FC) on three strains of Candida albicans were studied by flow cytometry (FCM). When the IFM4954 and IFM4949 were treated with AMPH or 5-FC alone, cytograms of cell distribution changed at the concentration of 1/2 MIC, respectively. Next, the effect of combination of AMPH and 5-FC were examined. Cytogram of cell distribution of IFM4954 and IFM4949 changed under the combination of 1/4 MIC of AMPH and 1/4 MIC of 5-FC, namely a synergic effect was observed. In conclusion, FCM is a useful apparatus for analysis of the effect of antifungal agents.

Amphotericin B↗

PubMed1992

[Immunohistochemical studies on tumor associated carbohydrate antigens in gastric cancers of different histological stages].

By comparing gastric cancer tissues treated by the conventional hematoxylin and eosin (HE) staining and those by the chemical staining of immunohistologicals using monoclonal antibodies (MoAB) which recognize different carbohydrate antigens, the relation of cancer tissue patterns between the two staining methods was studied. Consequently, stainability was not seen in MoAB-FH4, AH6, FH6 and TKH2 in the cancer tissues where MoAB-SH1 responded to immunohistological staining. Likewise, each of MoAB-FH4, AH6, FH6 was found to have its own stain localization. The patterns made by immunohistological staining using MoAB showed so-called mosaicism even where the HE stain presented the same histologic form. Study of correlation between gastric cancer patterns and MoAB's localization revealed that localization of MoAB-SH1, AH6 and TKH2 was predominant in well differentiated adenocarcinoma. On the contrary, MoAB-FH4 and FH6, which are more specific, showed predominant localization in poorly differentiated adenocarcinoma of gastric cancers. Localization of MoAB-FH6 and AH6 increased as cancer grew from the early stage to the advanced stage. These results leads to this assumption: cancer, being of an isogenic carbohydrate structure at the initial stage when carcinoma in situ is generated, gains heterogeneity with the process of growth, differentiating into various directions and thus changing into a complicated carbohydrate structure.

Adenocarcinoma↗

PubMed1992

Evaluation of duodenal papillary function by ERCP-CT and comparison with endoscopic measurement of pressure in the papillary sphincter zone.

Imaging of the main pancreatic duct on ERCP-CT (computerized tomography performed immediately after endoscopic retrograde cholangiopancreatography) was evaluated in 192 patients. Favorable images were obtained in elderly patients, as well as in those with main pancreatic duct dilation, chronic pancreatitis, papillary disease, and choledocholithiasis. In addition, we used a microtransducer inserted through a duodenoscope to measure papillary sphincter zone and main pancreatic duct pressure. We then compared the endoscopic results with the images achieved on ERCP-CT. The patients with favorable images showed higher pancreatic and papillary basal pressure and a faster wave cycle than those with poor images. In addition, significant differences in pancreatic duct pressure and basal pressure were seen. Peak papillary pressure showed no consistent correlations with imaging. Patients with favorable images exhibited an increase in the frequency of irregular papillary sphincter zone waves. We conclude from these findings that good images on ERCP-CT reflect a slow flow of pancreatic juice, which is closely associated with papillary stenosis.

Aging↗

PubMed1991

Virulence and pathogenicity of human and environmental isolates of Cladosporium carrionii in new born ddY mice.

Three strains of Cladosporium carrionii, two human isolates and one from a xerophilous plant, were used to study the effect of culture conditions in 106 newborn ddY mice. Growth in a complex medium (YPG) and a basal synthetic medium (BSM) was compared. Filamentous forms developed during static incubation while conidia were readily formed with shaking. Mice inoculated intraperitoneally were sacrificed and autopsied after 4 weeks. Mortality was related only to sporulated exponential phase growing cells. Invasiveness ability was preserved in all experimental conditions. BSM medium that inhibited exopigment formation appeared more suitable than YPG to obtain intact cells for further studies. Biochemical and physiological alteration associated with shape changes during differentiation of vegetative cells into spores could play an important role in virulence of C. carrionii.

Animals↗

PubMed1991

Studies on the relationship between the pathogenicity of Paracoccidioides brasiliensis in mice and its growth rate under different oxygen atmospheres.

We performed comparative studies of the pathogenicity of six strains of Paracoccidioides brasiliensis (Bt-9, Bt-4, Pb-9, Pb-18, Bt-7 and B-1183) for young adult male ddY mice and the growth rate of each strain under different oxygen atmospheres (aerobic, micro-aerobic and anaerobic atmospheres) at 37 degrees C. 10(6) units of yeast cells were intravenously injected into each mouse. The pathogenicity of each isolate was determined by a scoring system based on organ culture and histopathological findings. The growth rates under different oxygen atmospheres were determined by a scoring system in which 300 fungal units per strain were counted. The strain Bt-9 showed the greatest pathogenicity, followed by Bt-4, Pb-9 and Pb-18 had on intermediate rank of pathogenicity. Bt-7 and B-1183 were the least pathogenic of the strains tested. Except for strain Bt-7 all strains showed an excellent growth under an aerobic atmosphere. Bt-4 and Bt-9 also showed excellent growth under a micro-aerobic atmosphere, followed by Pb-9, whereas the growth of Pb-18, Bt-7 and B-1183 was limited. There was a correlation between the growth rate under a micro-aerobic atmosphere and the pathogenicity of a strain. The growth rate of P. brasiliensis under a micro-aerobic atmosphere strongly correlated to its pathogenicity.

Aerobiosis↗

PubMed1991

Studies on the relationship between paracoccidioidomycosis in ddY mice and their estrous cycle.

The relationship between paracoccidioidomycosis in ddY mouse and its estrous cycle was studied. Adult ddY mice of both sexes were used as experimental animals. Estrous cycle of female mice was examined before inoculation of Paracoccidioides brasiliensis yeast cells and mice were divided into 5 groups such as proestrus, estrus, metestrus-I, metestrus-II and diestrus. Each mouse was inoculated intravenously with 10(6) P. brasiliensis yeast cell units and sacrificed on day 28 after inoculation. Their internal organs were cultured, and in addition, their histopathologies were studied. As a result, there was no difference in the organ cultures among the male and the female mice of 5 groups. However, histopathologically, the female groups at estrus, metestrus-I and metestrus-II were affected more severely than the male group, and the susceptibility of the female mice to the fungus was closely related to their estrous cycles.

Adrenal Glands↗

PubMed1991

Reevaluation of the teleomorph of the genus Histoplasma by ubiquinone systems.

Ubiquinone systems of the genus Histoplasma and Blastomyces dermatitidis were examined and the relationship between the two genera, Emmonsiella and Ajellomyces, was discussed. Ubiquinone systems have been adopted as a useful taxonomic criteria at the generic level for fungi. We investigated ubiquinone systems of sexual and asexual strains of Histoplasma species and Blastomyces dermatitidis. All the strains of the former group had dihydrogenated ubiquinone-10(Q-10(H2] as the major isoprenologue, while the latter had ubiquinone-10(Q-10). From the result, it was concluded that the teleomorph of Histoplasma species should be brought back to Emmonsiella.

Ascomycota↗

PubMed1991

Resistance of Histoplasma capsulatum to killing by human neutrophils. Evasion of oxidative burst and lysosomal-fusion products.

The basis for resistance of yeast form of Histoplasma capsulatum to antifungal activity of human neutrophils was studied. In limiting dilution assays and short term coculture assays human neutrophils were ineffective in killing H. capsulatum whereas Candida albicans was readily killed. By contrast, in a cell free hydrogen peroxide-peroxidase-halide system H. capsulatum was as sensitive to killing as C. albicans. Moreover, lysate of human neutrophils effectively substituted for horse-radish peroxidase in a cell free system for killing H. capsulatum. H. capsulatum elicited significant products of the oxidative burst in human neutrophils as detected by luminol-enhanced chemiluminescence. However, the response was two-fold less (p less than 0.05) than that induced by C. albicans. Transmission electron microscopy studies showed that phagosome-lysosome fusion took place when neutrophils phagocytosed C. albicans or H. capsulatum. Taken together, these findings indicate that, even though H. capsulatum elicits an oxidative burst and phagosome-lysosome fusion within the phagosome, it is capable of evading damage in short term assays.

Cells, Cultured↗

PubMed1991

Fungistatic activity of human neutrophils against Histoplasma capsulatum: correlation with phagocytosis.

The interaction of human polymorphonuclear leukocytes (PMNL) and Histoplasma capsulatum was studied. In limiting dilution assays and in a 2-h coculture system, PMNL were ineffective in killing H. capsulatum whereas Candida albicans was readily killed. Although PMNL could not reduce inoculum colony-forming units of H. capsulatum in short-term assays, they were highly fungistatic in 24- (47%-55%) and 72-h (65%-75%) cocultures. Phagocytosis of yeast cells by PMNL was 81.3% +/- 3.7%. Fungistasis persisted even though PMNL viability decreased with time. Fungistatic activity of PMNL was dose dependent. Fungistasis was verified by direct hemocytometer counts of fungal units. In transwell experiments, PMNL contact with H. capsulatum was required for fungistatic activity. Lymphocytes, PMNL lysates, or PMNL supernatants were not fungistatic in this system.

Candida albicans↗

PubMed1991

Two endothelin receptor subtypes in porcine arteries.

Endothelin-1 (ET-1) and ET-3 caused constrictions of endothelium-denuded porcine coronary artery strips with different concentration-response curves: a typical sigmoidal curve to ET-1 and a two-phase sigmoidal curve to ET-3. Binding assays using a membrane preparation demonstrated different Bmax values for [125I]ET-1 and [125I]ET-3 binding. In addition, [125I]ET-1 binding was inhibited by ET-1 and ET-3 with different potencies (ET-1 greater than ET-3), while [125I]ET-3 binding was inhibited by both ETs equally. From these results, two distinct ET receptor subtypes were proposed in the artery; site 1 (selective to ET-1) and site 2 (equally sensitive to both ETs). However, only site 1 was identified on cultured arterial smooth muscle cells (VSMCs) by the binding assay, and this was confirmed since only ET-1 (not ET-3) caused a significant increase in the intracellular free Ca2+ concentration. Therefore, it seems likely that vasoconstriction is mediated via the binding of ET-1 to site 1 (VSMCs) and site 2 (non-VSMCs), or the binding of ET-3 to site 2 (non-VSMCs). Furthermore, site 2 was predominant in nonvascular tissues such as lung, kidney, and cerebellum, thereby suggesting that site 1 may exist in limited tissues such as VSMCs.

Animals↗

PubMed1991

Killing of Histoplasma capsulatum by gamma-interferon-activated human monocyte-derived macrophages: evidence for a superoxide anion-dependent mechanism.

The interaction of human macrophages with the yeast form of the thermally dimorphic fungal pathogen, Histoplasma capsulatum, was studied. Macrophages derived from monocytes by culture in vitro for 3 days ingested H. capsulatum, but were neither fungicidal or fungistatic. In contrast, when monocytes were exposed to human recombinant gamma-interferon (gamma-IFN) during their differentiation into macrophages, those macrophages were able to reduce the number of ingested or adherent cfu of H. capsulatum by 44-75% in 2 h. Activation of macrophages for fungicidal activity by gamma-IFN was dose dependent and 500-1000 units ml were optimal. Antibody to gamma-IFN abrogated the gamma-IFN activation process. Killing of H. capsulatum by activated macrophages in 2-h assays could be inhibited by superoxide dismutase but not by sodium azide.

Cell Adhesion↗

PubMed1991

[The treatment of pulmonary aspergilloma with itraconazole].

We evaluated the efficacy of Itraconazole (ITZ), a newly developed triazole antifungal agent, in 5 cases of pulmonary aspergilloma. A daily dose of 100-200 mg of ITZ was given orally for 5 to 20 months. In one patient, administration of ITZ was discontinued because of mild and transient hepatic injury. On computerized tomography and conventional roentgenogram of the chest, improvement was clearly observed in 2 of the remaining 4 cases. Symptomatic improvement, mainly disappearance of airway bleeding, was seen in 2 cases. Thus the overall improvement rate was 50% (two out of 4). No adverse response other than the hepatic injury mentioned above occurred. In one patient, who had two fungus balls previously, one of the fungus balls disappeared completely and the other decreased significantly in size during the course of treatment. In this case, the daily dose of ITZ was larger (200 mg once a day) and the plasma concentration of ITZ was extremely higher (2068 ng/ml) than in other cases (137-330 ng/ml). We conclude that ITZ is an efficacious drug in the treatment of pulmonary aspergilloma, and that this drug may be even more efficacious if we keep higher plasma concentration of ITZ.

Adult↗

PubMed1991

Phase II study of continuous venous infusion of 5-fluorouracil in advanced pancreatic cancer.

Continuous venous infusion of 5-fluorouracil (5FU) was investigated in 18 patients with measureable advanced cancer of the pancreas. 5FU was given for 7 days in a dose of 500 mg/m2 by continuous venous infusion over a 24-hour period and then followed by a dose of 170 mg/m2 for more than 28 days. Ten patients had no change including 1 patient with minor response, and 4 patients had disease progression. Serum CA19-9 levels were measured serially after chemotherapy in 13 of 14 evaluable patients. In 3 of 10 patients who showed high levels before treatment, serum CA19-9 levels were significantly decreasing after treatment.

Aged↗

PubMed1991

Depression of phagocytic activity of human polymorphonuclear leukocytes by methyl linoleate hydroperoxides.

Methyl linoleate hydroperoxides (MLHPO), a model for lipid hydroperoxides, decreased fungicidal activity of human polymorphonuclear leukocytes (PMN) for fungi of Candida albicans. When PMN was cultured with MLHPO, phagocytosis to fungi was depressed. Degree of the depression was dependent on the concentration of MLHPO and the treatment time with MLHPO. These findings indicate that phagocytic activity of human PMN can be depressed by lipid hydroperoxides.

Candida albicans↗

PubMed1991

[The defensive role of human pulmonary alveolar macrophages and polymorphonuclear leukocytes against a strongly or weakly virulent strains of Cryptococcus neoformans].

The phagocytic and killing activities of human pulmonary alveolar macrophages (PAM) and polymorphonuclear leukocytes (PMN), and superoxide (O2-) production in phagocytizing PAM and PMN were studied by using a strongly and weakly virulent strains of Cryptococcus neoformans (C. neoformans) in mice. The strongly virulent strain was encapsulated with a thick capsule while the other had a thin one. The phagocytic and killing activities of PAM and PMN against the strongly virulent strain were lower than against the weakly virulent one. There was no significant difference between PAM and PMN in terms of phagocytic or killing activities and O2- production. It seems likely that O2- plays no defensive role in the intracellular killing of C. neoformans by PAM and PMN because no correlation was found between the killing activity and O2- production. These results indicate that human PAM and PMN play an effective role in host defense against the weakly virulent strain of C. neoformans encapsulated with a thin capsule but are not effective against the strongly virulent strain encapsulated with a thick capsule.

Adolescent↗