Search PubMed⌕ Search

Biomedical subjects

O Maeda

Publications and source records attributed to O Maeda.

101 records · Page 6Linked to original sources
PubMed1982

Protection of pigs against mosquito-borne Japanese encephalitis virus by immunization with a live attenuated vaccine.

Pigs were vaccinated with an attenuated Japanese encephalitis virus (JEV) vaccine and challenged with virulent JEV, either by subcutaneous injection or by exposure to infected mosquitoes. The vaccinated pigs developed circulating antibodies to JEV. After challenge they did not develop viremia detectable by inoculation of their serum in suckling mice. They were also unable to transmit virus to mosquitoes fed on their skin. In contrast, unvaccinated pigs, whether challenged by injection or by mosquito bites, developed viremia and did transmit virus to mosquitoes which were allowed to bite them. Transmission seemed possible for only 3 days post-infection.

Animals↗
PubMed1978

Epidemiological studies on Japanese encephalitis in Kyoto City area, Japan. I. Evidence for decrease of vector mosquitoes.

Mosquito collections by using light traps have been carried out at 10 to 11 stations in Kyoto City area at intervals of about 10 days every year. Mean percent indexes (MPI), being calculated from the data of mosquito collections, were used for comparison of the annual abundance of mosquitoes. It is no doubt that Culex tritaeniorhynchus summorosus has decreased recently and this decrease is correlated with the reduction of human patients of Japanese encephalitis. Wide use of two herbicides, CNP and nitrofen, for rice plant cultivation, may probably be one of the reasons for the decrease of the mosquitoes.

Animals↗
PubMed1978

Epidemiological studies on Japanese encephalitis in Kyoto City area, Japan. III. Seasonal prevalence of virus infections in several pig populations shown by virus recovery from engorged Culex tritaeniorhynchus summorosus.

When vector mosquitoes engorged by feeding on pigs are tested for virus recovery after incubation for 7 to 10 days, the results may show mosquito infection itself. Therefore, seasonal prevalence of infection in each pig population can be estimated from course of the infection rate among mosquitoes. Many mosquitoes of the main vector of Japanese encephalitis virus, Culex tritaeniorhynchus summorosus, collected by light traps everyday or every other day in some pig sheds from 1967 to 1970 were tested for virus recovery after incubation. The tests were positive during about a month period each summer, and the peak infection rate was high being over 10%. The course of the mosquito infection showed a certain pattern with one or two peaks between the initial recovery and the highest peak. From the interval of 12 to 13 days after the first recovery to the peak, cyclic infection between the pig and the mosquito may occur at the same interval.

Animals↗
PubMed1978

Epidemiological studies on Japanese encephalitis in Kyoto City area, Japan. IV. Natural infection in sentinel pigs.

Natural infection with Japanese encephalitis virus in three sentinel pigs held in separate experimental huts was examined daily by virus recovery from blood samples of the pigs and from mosquitoes after incubation for about 7 days from their blood feeding and by HI antibody titration of the blood samples. After a period of low infection rates, below 6%, for about two weeks in engorged Culex tritaeniorhynchus summorosus, high mosquito infections of over 30% from each viremic pig occurred for two to three days. The pigs may be probably have been bitten by many infected but not infective mosquitoes in a period of about 10 days before infection.

Animals↗
PubMed1978

Epidemiological studies on Japanese encephalitis in Kyoto City area, Japan. II. Annual patterns of virus dissemination on virus recoveries from unfed Culex tritaeniorhynchus summorosus.

Annual patterns of dissemination of Japanese encephalitis virus in vector mosquitoes have been investigated at the main collection station from 1965 through 1973 at some other stations from 1969 through 1971. The virus was recovered usually from Culex tritaeniorhynchus summorosus during a period of about a month from July to August every year till 1969, and from August to September after 1970, although at some of the stations the virus was recovered intermittently for longer or shorter terms. Higher infection rates were recorded with the mosquitoes caught at the stations near to pig sheds than at the stations far from pig sheds. The infection rates at the peak of virus recovery in high epidemic year (1965 to 1967) were higher, being over 2%, than those in lower or latent epidemic years (1968 to 1973). Human patients of Japanese encephalitis were found in 17 to 20 days after the appearance of the highest peak of the infection rate in mosquitoes.

Animals↗
PubMedDate not supplied

Positive correlation between cytochrome P450 2E1 mRNA level and serum estradiol level in human uterine endometrium.

Most carcinogens are bioactivated by cytochrome P450s (CYPs) and these enzymes within target cells are closely related to susceptibility to cancer. Since extrahepatic CYPs occur typically at much lower levels, the existence and the role of CYP in extrahepatic tissues have been difficult to assess. In this study, we modified the reverse transcriptase-polymerase chain reaction (RT-PCR) to evaluate the relative quantities of CYP 2E1 mRNA in human endometrium. Total RNA from human endometrium was reverse-transcribed and co-amplified by PCR in the same tube containing both primer pairs of CYP 2E1 and beta-actin. The CYP 2E1 and beta-actin PCR products were 298 and 600 bp, respectively. The restriction enzyme MboI digested these two products to the predicted size for DNA fragments, demonstrating that both PCR products were specific and CYP 2E1 mRNA exists in human endometrium. CYP 1A1 mRNA was also examined, but could not be detected clearly. Adding [alpha-32P]dCTP to the reaction mixture made it possible to quantify the relative yield of the CYP 2E1 PCR product in comparison with the beta-actin product. The ratio of the yield of the CYP 2E1 PCR product to the beta-actin PCR product could be calculated at a point of 25 cycles of amplification. This ratio and serum estradiol levels were correlated positively (r = 0.654; p < 0.05), but no relationship to serum progesterone levels was observed.

Adult↗
PubMedDate not supplied

Expression of cytokines enhancing the osteoclast activity, and parathyroid hormone-related protein in prostatic cancers before and after endocrine therapy: an immunohistochemical study.

Cytokines, interleukin (IL)-1alpha, IL-1beta, IL-3, IL-6, macrophage colony stimulating factor (M-CSF) and tumor necrosis factor-alpha (TNF-alpha) as well as parathyroid hormone-related protein (PTHrP) have been shown to enhance the osteoclast activity. To investigate mechanisms of the development of bone metastasis of prostatic cancers, expression of these cytokines and PTHrP was examined immunohistochemically in prostatic cancers of patients administered no prior therapy or endocrine therapy. All cytokines and PTHrP were stained in the cytoplasm of the epithelium of non-cancerous prostatic glands, and IL-3 and IL-6 were stained in the cytoplasm of smooth muscle cells besides epithelial cells of non-cancerous prostatic glands. Incidences of positivity of staining in prostate cancers of patients administered no prior therapy were 100% for IL-1alpha, IL-1beta, IL-6, M-CSF and TNF-alpha, 20% for IL-3, and 80% for PTHrP. Incidence of prostatic cancers stained positively for IL-1alpha and IL-1beta decreased significantly in patients administered endocrine therapy, but those for IL-3, IL-6, M-CSF, TNF-alpha and PTHrP did not change significantly. The present results suggest that prostatic cancers produce various cytokines, IL-1alpha, IL-1beta, IL-3, IL-6, M-CSF and TNF-alpha, as well as PTHrP, and that expression of these cytokines and PTHrP except IL-1alpha and IL-1beta is not under androgen control. Cytokines and PTHrP produced by prostatic cancers may play a role in the development of bone metastasis of prostatic cancers.

Aged↗
PubMedDate not supplied

Glutathione related enzymes in cis-diamminedichloroplatinum (II)-sensitive and-resistant human ovarian carcinoma cells.

A cis-diamminedichloroplatinum (II) (CDDP)-resistant cell line (NOS2CR) demonstrated 7.4-fold greater resistance to CDDP compared with the parental cell line (NOS2) established from a patient with serous cystadenocarcinoma of the ovary. We investigated the role of enzyme systems associated with glutathione (GSH) in these cell lines. The GSH content was almost identical in both cell lines. Preincubation with 50 microM DL-buthionine-S, R-sulfoximine (BSO), an inhibitor of gamma-glutamyl cysteine synthetase, for 24 hr reduced the IC50 in both NOS2 and NOS2CR cells. Glutathione-S-transferase pi (GST-pi) activity and mRNA level in NOS2CR cells were higher than in NOS2 cells. However, gamma-glutamyltranspeptidase (GGT) activity in NOS2CR cells was 2.4-fold less than in NOS2 cells. The GST activity and mRNA level in both cell lines were constant when the cells were exposed to CDDP. Exposure to CDDP for 48 hr increased the GGT mRNA level 4.4 and 1.8 times in NOS2 and NOS2CR cells, respectively, compared with no exposure. By exposure to CDDP for 48 hr, the GGT activities in NOS2 and NOS2CR cells were increased 1.6-and 2.5-fold, respectively, compared with no exposure. The above data provide the first evidence that GGT activity and GGT mRNA are induced by CDDP in human carcinoma cell lines.

Blotting, Western↗
PubMedDate not supplied

Potentiating effect of amphotericin B on five platinum anticancer drugs in human cis-diamminedichloroplatinum (II) sensitive and resistant ovarian carcinoma cells.

We have determined an effect of amphotericin B (AMB), an antifungal drug, on the cytotoxicity of cis-diamminedichloro-platinum (II) (CDDP) and 4 CDDP analogues in a human ovarian carcinoma cell line (NOS2). Intracellular accumulation of CDDP was elevated significantly by treatment with AMB, and AMB significantly potentiated the cytotoxicity of CDDP by MTT assay. Intracellular accumulation of 4 CDDP analogues was also elevated by the treatment with AMB and the order of increasing accumulation rate of platinum drugs was consistent with that of dose modification factor (DMF). AMB also increased the intracellular CDDP accumulation in CDDP resistant cells (NOS2CR), derived from NOS2. The intracellular accumulations of 4 CDDP analogues were elevated slightly by the treatment with AMB in NOS2CR cells. DMFs of 5 platinum drugs in NOS2CR cells, however, were more than those in NOS2 cells. These results indicate that AMB sensitizes NOS2 and NOS2CR cells to platinum drugs, partially due to the increasing intracellular accumulation of these drugs. In addition, CDDP analogues are more effective in NOS2CR cells than CDDP, but the cytotoxicity of CDDP was most potentiated by AMB among the 5 platinum drugs under study.

Amphotericin B↗
PubMedDate not supplied

A newly synthesized bifunctional inhibitor, CKA1083, enhances adriamycin activity against human ovarian carcinoma cells.

BACKGROUND: A newly synthesized drug, CKA1083 ((S)-N-[2-(4-benzyloxy-carbonylpiperazinyl)-1-(P-methoxybenzyl) ethyl]-N-methyl-N(5-isoquinolinesulfonamide)), has the same glutathione-S-transferase (GST)-binding site structure as W-77, a bifunctional inhibitor that enhances the cytotoxicity of Adriamycin for human ovarian carcinoma cells. We examined the effects of CKA1083 on the cytotoxicity of Adriamycin and the resistance of human ovarian carcinoma cells to this drug. MATERIALS AND METHODS: We used GST-pi transfected cells and Adriamycin-sensitive or -resistant cells of human ovarian carcinoma. GST-pi activity, the intracellular Adriamycin content, and the cytotoxicity of Adriamycin in these cell lines in the presence or absence of CKA1083 were measured and compared to the findings obtained with W-77 or verapamil. RESULTS: CKA1083 inhibited GST-pi activity in an uncompetitive manner and more strongly than W-77. It enhanced the cytotoxicity of Adriamycin for GST-pi transfected cells by about 3-times. Further, CKA1083 increased the intracellular Adriamycin content about 3-fold in two Adriamycin-resistant cell lines (NOS2AR and NOS3AR). CKA1083 (10 microM) reduced the IC50 of Adriamycin to 1/38 in NOS2AR cells and 1/21 in NOS3AR cells, and overcame Adriamycin resistance more effectively than both W-77 and verapamil. CONCLUSIONS: CKA1083 enhanced the antitumor effect of Adriamycin more than W-77 by inhibiting both GST activity and P-glycoprotein.

Antineoplastic Agents↗