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Katsuhiko Kamei

Publications and source records attributed to Katsuhiko Kamei.

At least 19 recordsLinked to original sources
PubMed2007

Effect of dietary oils on lymphocyte immunological activity in psychologically stressed mice.

Psychological stress has been shown to modulate immune functions. In this study, we investigated the effect of dietary oils (olive oil, soybean oil, and fish oil) on the social isolation stress-induced modulation of lymphocyte immunological activities in mice. In olive oil-fed, but not soybean oil- or fish oil-fed, mice, a 2-week isolation stress decreased the lymphocyte proliferative response, reduced the interferon-gamma and interleukin (IL)-10 secretions and increased the IL-4 secretion by lymphocytes. The isolation stress reduced the arachidonic acid content of lymphocytes markedly, moderately, and not at all in the olive oil-, soybean oil-, and fish oil-fed mice, respectively. In the olive oil-fed, but not soybean oil- or fish oil-fed, mice, the isolation stress up-regulated the expression level of mRNA for splenic heat-shock protein 70 and increased lymphocyte sensitivity to the antiproliferative effect of corticosterone. This is the first demonstration that effect of psychological stress on lymphocyte immunological activities can vary depending upon the dietary fatty acid composition.

Animals↗
PubMed2006

Ethanol production by Candida albicans in postmortem human blood samples: effects of blood glucose level and dilution.

We present two cases in which the ethanol concentration in blood samples taken after death continued to increase in the absence of any remarkable increase in n-propanol concentration. Species of bacteria and yeasts, including Candida albicans were isolated from these samples. We then examined whether C. albicans, the most common yeast in the general environment, was able to produce ethanol in human blood stored at room temperature. Ethanol production increased as the glucose concentration increased, indicating that C. albicans produced ethanol from the glucose. Our results also suggested that C. albicans produced ethanol more easily in blood diluted by intravenous infusions that included glucose than in undiluted blood. These findings are useful for the evaluation of postmortem ethanol production in subjects whose blood has been diluted by infusions with glucose. Furthermore, there was no quantitative relationship between the amount of n-propanol detected and the amount of ethanol production: n-propanol appears to be an unreliable index of putrefaction and postmortem ethanol production by C. albicans. It is possible for the blood ethanol level to be high and n-propanol not to be detected, even if the subject has not been drinking alcohol. We reconfirmed the necessity of immediately adding sodium fluoride to samples for ethanol analysis to prevent postmortem ethanol production.

1-Propanol↗
PubMed2006

Reexamination of Coccidioides spp. reserved in the Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University, based on a multiple gene analysis.

The Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University is the only organization in Japan to possess a series isolates of Coccidioides spp., which are the most virulent pathogenic fungi and which are treated as biosafety level 3 microorganisms. Recently, the genus Coccidioides has been classified into two species, C. immitis and C. posadasii, based on their endemic areas and genotyping; the former species is endemic to the state of California, and the latter is endemic to other parts of North and South America. We reevaluated 19 isolates of Coccidioides immitis stored in our center using a multiple gene analysis. Five isolates were identified as C. immitis and 14 as C. posadasii. Their sequence information in GenBank will help to identify the two genospecies of Coccidioides spp.

Coccidioides↗
PubMed2005

Rapid identification of Ochroconis gallopava by a loop-mediated isothermal amplification (LAMP) method.

Ochroconis gallopava is a species of dematiaceous fungi recognized as a causative agent of zoonotic and emerging fungal infections. It affects the central nervous system and respiratory tracts of humans, birds and cats. We designed O. gallopava species-specific primer sets to aid in its identification by a loop-mediated isothermal amplification (LAMP) method based on the D1/D2 domain of the LSU rDNA sequence. The LAMP method successfully detected the gene from both fungal DNA and experimentally infected brains and spleens of mice and will be helpful in the diagnosis of O. gallopava infection.

Animals↗
PubMed2005

A murine model of pulmonary basidiomycosis by Schizophyllum commune.

Schizophyllum commune has recently emerged as a causative agent of human mycosis, but the details of its virulence are not yet known. To elucidate the pathogenicity of S. commune, a murine model of invasive pulmonary infection was established. ICR mice, not immunosuppressed or immunosuppressed by cortisone acetate, were infected with S. commune by intratracheal inoculation with agar beads containing the basidiospores. All immunosuppressed mice died within 2 weeks. Pathology examination revealed massive mycelial invasion into the lungs, penetration into adjacent vessels, and systemic dissemination, suggesting much higher virulence of this fungus than was previously estimated. This is the first murine model of pulmonary infection by S. commune, which we believe can be of assistance during subsequent investigations of this infection.

Animals↗
PubMed2005

Trichosporon species isolated from guano samples obtained from bat-inhabited caves in Japan.

Yeasts from caves have rarely been examined. We examined yeasts collected from bat guano samples from 20 bat-inhabited limestone and volcanic caves located in 11 prefectures in Japan. Of approximately 700 yeast-like colonies, nine Trichosporon species were recovered from 15 caves. Two of these were known species, and the remaining seven are potentially novel species, based on molecular phylogenetic analyses. In addition to Trichosporon species, identifiable strains of eight ascomycetous yeasts and one basidiomycetous yeast were recovered at frequencies of 5 to 35%. Our findings suggest that Trichosporon spp. are the major yeast species in bat guano in Japan and that bat guano is a potentially rich source of previously undescribed yeast species.

Animals↗
PubMed2005

Pulmonary coccidioidomycosis that formed a fungus ball with 8-years duration.

Coccidioidomycosis, caused by inhaling Coccidioides immitis, is a mycosis imported from endemic regions including the southwestern United States. C. immitis is so virulent that even a short-term stay in the endemic area can provide a chance for infection. Here, we report a 33-year-old Japanese man with formation of a fungus ball inside the pulmonary cavity secondary to coccidioidomycosis with a duration of 8 years, which is considered rare. He was infected with C. immitis in the United States in 1996. A nodule remained in the lung, which later cavitated with fungus ball formation. We identified Coccidioides immitis in the cultured specimen from the cavity and serum antibodies against it. We performed a lobectomy in 2003 since anti-fungal treatment was only temporarily effective. He is still free of disease 6 months later.

Adult↗
PubMed2005

The Pathogenicity of Stachybotrys chartarum.

Stachybotrys chartarum is a dematiaceous fungus that is ubiquitous in our living environment. This fungus has long been regarded as non-pathogenic and its inhalation effect on humans has been scarcely studied. Recently, however, epidemiologic studies on acute idiopathic pulmonary hemorrhage in infants suggested that the fungus might be potentially pathogenic to humans. To determine the pathogenicity of this fungus, its interaction with the host defense system was studied using polymorphonuclear leukocytes (PMNs) and macrophages. Histopathological analysis of mice intratracheally injected with this fungus was also performed. The results disclosed that the conidia of S. chartarum were resistant to the antifungal activities of alveolar macrophages in terms of phagocytosis, killing and inhibition of germination. However, the conidia could not survive in the lungs of mice when injected intratracheally. Lavage fluid of mycelia that contained the dark slimy material coating the surface of conidia showed cytotoxic activity against macrophages and PMNs. Intratracheal injection of conidia in mice resulted in intraalveolar infiltration of PMNs. When using multiple injections during a 3-week period, strong eosinophilic infiltration into the proximal alveoli and perivascular tissues was observed. Our results suggest that inhalation of conidia may cause serious damage to the human lung, particularly when repeated.

Animals↗
PubMed2005

[Imported mycoses in Japan: their present status and problems].

Imported mycoses in Japan, particularly coccidioidomycosis and histoplasmosis, have been on the increase in the past 15 years, and more than 40 patients have been reported to suffer from each of these diseases. In spite of their high infectivity and virulence, imported mycoses have received little attention by physicians. Concerning coccidioidomycosis, in particular, physicians should keep abreast of updated and detailed information, and should maintain close contact with clinical microbiologists. In this review, the general profile of coccidioidomycosis, including its diagnosis and treatment, was described, and the importance of these diseases as well as their recent trends were discussed.

Coccidioides↗
PubMed2005

[A case of black dot ringworm caused by Trichophyton tonsurans in Chiba Prefecture].

A 74-year-old woman visited a clinic in Kisarazu, Chiba Prefecture in December 2002 complaining of itching, scale and alopecia. She had been diagnosed as having tinea capitis by a direct microscopic examination of scales, and been treated with an antifungal cream and steroid lotion since 1999. The bald area spread from frontal to occipital in which multiple black dots and red papules were scattered. Abundant endothrix spores were observed in the hair shaft. A mycelial colony was isolated from the black dots. A giant colony on Sabouraud's agar was white, powdery and flattened with cottony elevation at the center in the obverse, and a reddish-brown pigmentation in the reverse. The isolate produced abundant microconidia that were round to club-and balloon-shaped with extreme swelling, while macroconidia and spiral bodies were few. Hair perforation test was negative and urease activity test was positive. ITS1-5.8S-ITS2 rDNA sequencing revealed 100% homology with T. tonsurans isolated from two old women in Niigata Prefecture. On the other hand, 3 bases were different from those of the outbreak isolates from judo and wrestling players infected through international matches. T. tonsurans has polymorphism and the present isolate might be an autochthonous genotype in Japan. This is the first time T. tonsurans was isolated in Chiba Prefecture. But this prefecture had been known as an endemic area of Trichophyton coccineum, which was very similar in morphological and physiological characteristics to those of T. tonsurans before World War II. These facts raise the question of whether T. tonsurans has existed in this prefecture before.

Aged↗
PubMed2005

Phylogenetic analysis of Histoplasma capsulatum based on partial sequence of the D1/D2 region of the 28S rRNA gene.

In order to confirm the phylogenetic relationships of Histoplasma capsulatum, the partial sequences of large subunit (28S) ribosomal gene (D1/D2 region) of 49 isolates were studied. The similarity values of the 49 isolates were more than 99.0% across 617 base pairs, however, the 49 isolates were divided into 9 groups. These 9 groups were independent of 3 varieties, var. capsulatum, var. farciminosum and var. duboisii. These results showed that analysis of the nucleotide sequence of the 28S rRNA gene was very effective for identification of H. capsulatum and that three varieties of H. capsulatum should be reclassified according to the phylogenetic relationship established from analysis of the D1/D2 region sequences.

Animals↗
PubMed2004

Detection of gp43 of Paracoccidioides brasiliensis by the loop-mediated isothermal amplification (LAMP) method.

Paracoccidioidomycosis is a deep mycosis caused by the thermo-dependent dimorphic fungus Paracoccidioides brasiliensis and is prevalent in Latin American countries. We detected the species specific gp43 gene of P. brasiliensis by loop-mediated isothermal amplification (LAMP) in 22 clinical and seven armadillo-derived isolates. The amplified DNA appeared as a ladder with a specific banding pattern. The advantage of the LAMP method is speed; only 3 h were necessary for identification of the organism and diagnosis of the disease. We were also able to obtain positive results from DNA extracted from a paraffin-embedded tissue sample of paracoccidioidomycosis, suggesting that this method may achieve clinical application in the near future.

Animals↗
PubMed2004

Cytotoxic substances from Aspergillus fumigatus in oxygenated or poorly oxygenated environment.

Aspergillus fumigatus often causes serious health problems. The airway of the human body, the most common initial site of damage, is always exposed to an oxygenated condition, and the oxygen concentration may play a critical role in the virulence of A. fumigatus. In this study, oxygen content, fungal growth, the production of cytotoxic substance(s) in the fungal culture, and their relationship were investigated. Two clinical strains of A. fumigatus were cultured under certain oxygen contents (10, 14 and 20%), and cytotoxicity of their culture filtrates on murine macrophages and their fungal growth were evaluated. The components of these filtrates were analyzed by gas chromatography-mass spectrometry. All culture filtrates contained gliotoxin and showed potent cytotoxicity on macrophages at very low concentration. The amount of gliotoxin in the culture filtrate prepared at 10% oxygen was markedly less, but diminutions in fungal growth and cytotoxicity of this culture filtrate were negligible. These results suggest that a well-oxygenated condition is suitable for the production of gliotoxin by A. fumigatus. A significant role of cytotoxic substances(s) other than gliotoxin is also suggested.

Animals↗
PubMed2004

Susceptibility of Pseudallescheria boydii and Scedosporium apiospermum to new antifungal agents.

Hyalohyphomycoses caused by Pseudallescheria boydii and Scedosporium apiospermum have recently been on the increase. To find the appropriate treatment for this emerging disease, we examined the antifungal susceptibility of 10 isolates of P. boydii and 17 isolates of S. apiospermum, most of which were isolated from clinical specimens. When the NCCLS M38-P microdilution method was used, itraconazole showed strong antifungal activities, while amphotericin B had little efficacy. A new triazole agent, voriconazole showed a strong effect against isolates of P. boydii and S. apiospermum (MIC50 0.06 micro g/ml), whereas micafungin, a newly developed echinocandin, had little effect (MIC50 >16 micro g/ml). There was no significant difference in the susceptibilities between P. boydii and S. apiospermum isolates against any antifungal agents. Our study suggests that voriconazole is a promising new drug in these infections, and that the same antifungal strategy can be employed in the infections by P. boydii and S. apiospermum.

Antifungal Agents↗
PubMed2004

Effect of aeration on gliotoxin production by Aspergillus fumigatus in its culture filtrate.

Gliotoxin, one of the mycotoxins produced by Aspergillus fumigatus, has various, potent bioactivities. However, it has not been considered to be a toxic (or virulence) factor because of its slow production. The aim of the present study was to investigate the effects of aeration on the cytotoxicity of A. fumigatus culture filtrate, and to determine the optimal condition for the rapid production of gliotoxin from this fungus. Fungal culture filtrates were made in three different containers under various conditions of aeration and O2 concentration. These filtrates were compared in terms of their cytotoxicity on murine macrophages and analyzed by gas chromatography. The culture filtrate showed high cytotoxicity when it was made under highly aerated conditions, but it was significantly less cytotoxic when prepared under non-aerated conditions. The cytotoxic activity became evident within 15 h of culture at 20% O2, when the fungus had already started producing gliotoxin. The culture filtrates also contained some other as yet unidentified substances that might also to some extent contribute to the cytotoxicity. In light of these results, the authors propose that a highly aerated condition is responsible for the rapid production of gliotoxin, and that gliotoxin might play an important role in the respiratory infection by A. fumigatus, with other toxic substances acting additively or synergistically.

Animals↗
PubMed2004

Effect of aeration on gliotoxin production by Aspergillus fumigatus in its culture filtrate.

Gliotoxin, one of the mycotoxins produced by Aspergillus fumigatus, has various, potent bioactivities. However, it has not been considered to be a toxic (or virulence) factor because of its slow production. The aim of the present study was to investigate the effects of aeration on the cytotoxicity of A. fumigatus culture filtrate, and to determine the optimal condition for the rapid production of gliotoxin from this fungus. Fungal culture filtrates were made in three different containers under various conditions of aeration and O2 concentration. These filtrates were compared in terms of their cytotoxicity on murine macrophages and analyzed by gas chromatography. The culture filtrate showed high cytotoxicity when it was made under highly aerated conditions, but it was significantly less cytotoxic when prepared under non-aerated conditions. The cytotoxic activity became evident within 15 h of culture at 20% O2, when the fungus had already started producing gliotoxin. The culture filtrates also contained some other as yet unidentified substances that might also to some extent contribute to the cytotoxicity. In light of these results, the authors propose that a highly aerated condition is responsible for the rapid production of gliotoxin, and that gliotoxin might play an important role in the respiratory infection by A. fumigatus, with other toxic substances acting additively or synergistically.

Aerobiosis↗