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Biomedical subjects

M Sekimoto

Publications and source records attributed to M Sekimoto.

At least 19 recordsLinked to original sources
PubMed2001

Usefulness of repeated direct intratumoral gene transfer using hemagglutinating virus of Japan-liposome method for cytosine deaminase suicide gene therapy.

To investigate the feasibility of repeated gene transfection in suicide gene therapy against human solid tumors by a combination of 5- fluorocytosine (5-FC) and its converting enzyme, cytosine deaminase (CD), we repeatedly transfected the yeast CD gene into the human pancreatic cancer cell line BXPC3 using the hemagglutinating virus of Japan-liposome in a new gene transfer method. The in vivo growth of the s.c. transplanted BXPC3 tumor in nude mice given CD-gene transfection was significantly suppressed by i.p. injection of 5-FC when compared with tumors treated with the control vector. Furthermore, the tumor transfected with the CD gene during a 7-day interval was suppressed much more than that of a single transfection. These results suggest that repeated transfection of the suicide gene together with the combination of 5-FC and the yeast CD gene using the hemagglutinating virus of Japan-liposome gene transfer method may be useful for the treatment of human solid tumors, including pancreatic cancer.

Animals↗
PubMed2001

The defibrillation system of basic emergency medical technicians in Japan: a comparison with other systems from a 14-year review of out-of-hospital cardiac arrest reports.

Although seven years have passed after basic emergency medical technician (EMT) defibrillation system was introduced in Japan, the overall survival for out-of-hospital cardiac arrest (OHCA) remains poor. We investigated factors leading to such an unanticipated result in Japan by comparing the data of OHCA in Japan with those in other countries. We obtained population-based OHCA data from three communities in Japan. We also performed a comprehensive literature and manual search to identify reports that included rates for incidence and survival or provided sufficient data for the calculation of these rates of OHCA. Statistical analysis was performed to compare survival and incidence rates between the communities. We identified 36 articles from 16 countries by a comprehensive literature search. There was no significant difference in incidence and survival rates among communities in Japan. Although the incidence rate of collapse-witnessed OHCA with ventricular fibrillation (VF) was much lower in Japan than western countries, the proportions of survival from it were comparable to those. Basic-EMT defibrillation system in Japan has yielded excellent result in terms of the survival of VF cases. However, much lower proportion of VF to all cases is responsible for lower overall rates of survival from OHCA in Japan.

Chi-Square Distribution↗
PubMed2000

Indispensable role for TNF-alpha and IFN-gamma at the effector phase of liver injury mediated by Th1 cells specific to hepatitis B virus surface antigen.

We report the development and characterization of a novel model of severe hepatitis induced against hepatitis B virus surface Ag (HBsAg). HBsAg was successfully targeted into the liver in soluble form. Using this unique property of HBsAg, we established a liver injury model induced by HBsAg-specific Th1 cells. Severe liver injury was induced in C57BL/6 mice by injection of HBsAg together with HBsAg-specific Th1 cells. Histochemical examination demonstrated extensive necroinflammatory hepatic lesions in these animals. Application of this liver injury model to mutant or gene knockout mice enabled us to define the effector mechanisms of Th1 cells in fulminant hepatitis. When Fas-deficient lpr mice were used as recipients, a similar degree of liver injury was induced as in wild-type mice. Moreover, HBsAg-specific Th1 cells obtained from perforin-/- mice could induce severe liver injury in both wild-type and lpr mice. These results indicated that neither Fas ligand nor perforin are essential for Th1-mediated liver injury in this model. Pretreatment with anti-TNF-alpha mAb prevented liver injury, whereas severe liver injury was induced in TNF-alpha-/- mice. Moreover, IFN-gamma receptor-deficient mice were resistant to Th1-mediated liver injury. Therefore, TNF-alpha and IFN-gamma, which were produced by HBsAg-specific Th1 cells during the effector phase, appeared to be indispensable in the pathogenesis of fulminant hepatitis.

Animals↗
PubMed2000

Interleukin-4-dependent induction of preproenkephalin in antigen-specific T helper-type 2 (Th2) cells.

Naive Th cells obtained from OVA(323-339)-specific DO11.10 TCR-Tg mice did not express preproenkephalin (PPE) mRNA. However, culture of naive Th cells with OVA(323-339) peptide (OVA-pep) plus IL-2 under Th2-inducing conditions for 7 days resulted in an induction of PPE mRNA. The PPE mRNA was also induced by culturing with OVA-pep plus IL-2 (neutral condition). However, PPE mRNA induction under neutral conditions was totally abrogated by addition of anti-IL-4 mAb. The existence of methionine-enkephalin was also demonstrated in peptidase-digested peptides derived from Th2 cell lysate. These results demonstrate that IL-4 is a critical factor for the induction of PPE mRNA in freshly expanded antigen-specific Th2 cells.

Animals↗
PubMed2000

Observation of a spin-flip M1 transition in 7(lambda)Li.

Using a large-acceptance germanium detector array (Hyperball), we have observed a spin-flip M1 gamma transition between the ground-state spin doublet of (7)(Lambda)Li (3/2(+)-->1/2(+)). The observed energy of 691.7+/-0.6(stat)+/-1.0(syst) keV provides crucial information on the strength of the spin-spin interaction between a Lambda and a nucleon. This is the first observation of well-identified hypernuclear gamma transitions using germanium detectors.

Journal Article↗
PubMed2000

Overexpression of CDC25B phosphatase as a novel marker of poor prognosis of human colorectal carcinoma.

There is evidence to suggest that CDC25B phosphatase is an oncogenic protein. To elucidate the role of CDC25B in colorectal carcinoma, we examined the expression of CDC25B at the mRNA and protein levels. Reverse transcription-PCR assay indicated that CDC25B was overexpressed in tumor tissues relative to normal mucosa in 6 of 10 cases. Using immunohistochemistry, we identified high expression of CDC25B in 77 of 181 colorectal cases (43%). Univariate analysis showed that high expression was a significant predictor for poor prognosis compared with low expression (5-year survival rate; 59% versus 82%, respectively; P < 0.0001). Multivariate analysis indicated that CDC25B was an independent prognostic marker (risk ratio for death, 3.7; P < 0.0001) even after controlling for various factors such as lymph node metastasis, tumor size, degree of differentiation, and depth of invasion. Furthermore, the level of CDC25B expression clearly predicted the outcome of patients with Dukes' B and Dukes' C tumors. On the other hand, CDC25A mRNA was overexpressed in 9 of 10 colorectal cancer cases, and immunohistochemistry for CDC25A showed high expression in 52 of 111 cases (47%), but no significant correlation with prognosis. Our findings suggest that CDC25B is a novel independent prognostic marker of colorectal carcinoma and that it may be clinically useful for selecting patients who could benefit from adjuvant therapy.

Adult↗
PubMed2000

Asymmetry in the nonmesonic weak decay of polarized (5)(Lambda)He hypernuclei

We have measured the asymmetric emission of protons from the nonmesonic decay of polarized (5)(Lambda)He produced by the (pi(+), K+) reaction. (5)(Lambda)He is an s-shell hypernucleus and its polarization is due to the Lambda. One expects to obtain direct information on the elementary weak Lambda-->p-->np process. The asymmetry parameter has been determined to be 0.24+/-0.22. The implication of the result is discussed.

Journal Article↗
PubMed2000

Genetic polymorphisms of human melatonin 1b receptor gene in circadian rhythm sleep disorders and controls.

Recent studies suggest that melatonin 1b (Mel1b) receptor, as well as melatonin 1a (Mel1a) receptor, is involved in the modulation of circadian rhythms in mammals. Mutational analysis was performed in the entire coding region of the human Mel1b receptor gene using genomic DNA from sleep disorder subjects. We have identified two missense mutations, G24E and L66F. However, neither is likely to be associated with sleep disorders in our study population. One of the subjects with non-24-h sleep-wake syndrome carries missense mutations in both the Mel1a and Mel1b receptor genes.

Adult↗
PubMed2000

alpha-galactosylceramide induces early B-cell activation through IL-4 production by NKT cells.

alpha-Galactosylceramide (alpha-GalCer), a glycolipid antigen, specifically activates natural killer T (NKT) cells by a CD1d-restricted mechanism. In this work, we found that in vivo administration of alpha-GalCer resulted in the activation of B cells in addition to NKT cells, namely, alpha-GalCer administration caused upregulation of the early activation marker, CD69, on both NKT and B cells. In addition, expression of B7.2 and I-A(b) on B cells was greatly upregulated by alpha-GalCer. However, serum levels of IgE, IgG1, and IgG2a were not significantly changed within 48 h. In the present experiments, it was also demonstrated that the upregulation of CD69 expression by alpha-GalCer was strongly blocked by anti-IL-4 monoclonal antibody. Moreover, B-cell activation by alpha-GalCer was not observed in NKT-deficient mice. These results suggested that antigen-stimulated NKT cells might play a critical role not only in early defense mechanisms but also in early B-cell activation through IL-4 production.

Animals↗
PubMed2000

Selective augmentations of intratumoral 5-fluorouracil concentration by local immunotherapy with OK-432 and fibrinogen.

PURPOSE: Pyrimidine nucleoside phosphorylase is an enzyme that converts 5'-deoxy-5-fluorouridine into its active metabolite, 5-fluorouracil. In colorectal cancer tissue pyrimidine nucleoside phosphorylase has been proven to be produced by macrophages in the cancer stroma despite presence of the cancer cells. We reported that local immunotherapy with OK-432 and fibrinogen induced aggregation of macrophages in the cancer stroma and enforced their pyrimidine nucleoside phosphorylase expression. Thus it was hypothesized that if colon cancer were treated with 5'-deoxy-5-fluorouridine, the 5-fluorouracil concentration in cancer tissues would be enhanced by local immunotherapy. The present study was conducted to investigate whether local immunotherapy for colon cancer could increase the intratumoral 5-fluorouracil concentration in patients given chemotherapy with 5'-deoxy-5-fluorouridine. METHODS: Twenty patients with resectable colorectal cancer were examined in this study. They were given 5'-deoxy-5-fluorouridine (600 mg/day) orally for seven days preoperatively. Nine randomly selected patients underwent intratumoral injection of OK-432 mixed with fibrinogen, which was performed on the third preoperative day (OK-432 and fibrinogen plus 5'-deoxy-5-fluorouridine group); eleven patients were given oral 5'-deoxy-5-fluorouridine only (5'deoxy-5-fluorouridine group). The 5-fluorouracil concentration in tumor tissue and normal colon mucosa tissue was measured, and the influence of the local immunotherapy was assessed. RESULTS: The 5-fluorouracil concentration in the cancer tissue was increased by the local immunotherapy, whereas that in the normal colon mucosa was not influenced. Thus, the influence of local immunotherapy was selective to the cancer tissue where the mixture of OK-432 and fibrinogen was injected. CONCLUSION: In patients with colorectal cancer, selective high 5-fluorouracil concentration in the cancer tissue could be achieved by a combination of 5'-deoxy-5-fluorouridine and local immunotherapy with a mixture of OK-432 and fibrinogen.

Aged↗
PubMed2000

The critical role of Th1-dominant immunity in tumor immunology.

To investigate the precise role of antigen-specific Th1 and Th2 cells in tumor immunity, we developed a novel adoptive tumor-immunotherapy model using OVA-specific Th1 and Th2 cells and an OVA gene-transfected tumor. This therapeutic model demonstrated that both antigen-specific Th1 and Th2 cells had strong antitumor activity in vivo with distinct mechanisms. However, immunological memory suitable for the generation of tumor-specific cytotoxic T lymphocytes was induced only when tumor-bearing mice received Th1 cell therapy, but not Th2 cell therapy. Thus it was strongly suggested that Th1-dominant immunity is critically important for the induction of antitumor cellular immunity in vivo. We also proposed that several immunomodulating protocols using interleukin (IL)-12, IL-12 gene, the natural killer T cell ligand alpha-galactosylceramide, or Th1 cytokine-conditioned dendritic cells might be useful strategies for the induction of Th1-dominant immunity essential for the development of tumor-specific immunotherapy.

Animals↗
PubMed2000

Appraisal of treatment strategy by staging laparoscopy for locally advanced gastric cancer.

More accurate preoperative staging is necessary to determine the treatment strategy for locally advanced gastric cancer. Thirty-two patients with T3 or T4 gastric cancer expected to undergo curative resection based on conventional examinations underwent staging laparoscopy. The disease stages determined were compared with those obtained by conventional methods. The discrepancy rate of disease staging was 16 of 32 (50.0%), with down-staging in 5 of 32 (15.6%) and up-staging in 11 of 32 (34.4%). Of the 32 patients, 13 (40.6%) were found to have unsuspected peritoneal dissemination. The positive predictive value for peritoneal metastasis by staging laparoscopy was 100%, whereas the negative predictive value was 89% (17/19). The accuracy rate was 94%. After laparoscopy, 15 of the 32 (46.9%) were diagnosed as candidates for curative resection. Of these 15 patients who underwent surgery, 13 (86.7%) underwent curative resection (1 R0 and 12 R1); the remaining two underwent R2 resection because of peritoneal metastasis that was undetected by staging laparoscopy. Patients with tumors judged noncurable by laparoscopy (n = 11) received neoadjuvant chemotherapy. In 7 of the 11 cases, salvage surgery was done (one R0, three R1, three R2 resections). A second staging laparoscopy was performed in four cases to determine the indication for salvage surgery. Three of the four were judged to be curable and underwent curative resection. Staging laparoscopy is an effective tool for detecting unsuspected peritoneal metastasis, and it can increase the curative resection rate and decrease unnecessary laparotomy for advanced gastric cancer. Second-look laparoscopy enables accurate assessment of the chemotherapeutic response, which can help in decisions about salvage surgery.

Adenocarcinoma↗
PubMed2000

Influence of CO2 pneumoperitoneum during laparoscopic surgery on cancer cell growth.

BACKGROUND: CO2 pneumoperitoneum provides a new surgical environment to treat malignant disease. The purpose of this study was to investigate the influence of CO2 pneumoperitoneum during laparoscopic surgery on cancer cell growth. METHODS: WiDr human colon cancer cells were incubated for 3 h under the following two conditions: 100% CO2 at 10 mmHg, and 95% air/5% CO2 (control). Cell proliferation was assessed by the WST-1 assay and BrdU assay. Tumor growth was assessed by subcutaneous injection into 20 nude mice. Cellular damage was measured by lactate dehydrogenase (LDH) assay. RESULTS: The number of WiDr cells under pneumoperitoneal conditions decreased in the first 24 h. However, no significant difference was observed in the proliferation rate and tumor growth of the viable cells. LDH release of the CO2 pneumoperitoneal group was higher than that of the controls. CONCLUSIONS: Our data indicate that CO2 pneumoperitoneum does not promote cancer cell proliferation but instead has a toxic effect on cancer cells.

Carbon Dioxide↗
PubMed2000

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Journal Article↗
PubMed2000

28-Norcastasterone is biosynthesized from castasterone.

Metabolic experiments with deuterium-labeled castasterone in seedlings of Arabidopsis thaliana, Oryza saliva and Lycopersicon esculentum, and cultured cells of Catharanthus roseus were performed, and the metabolites were analyzed by GC-MS. In all the plant species examined, [2H3]28-norcastasterone was identified as a metabolite of [26,28-2H6]castasterone, indicating that castasterone is the biosynthetic origin of 28-norcastasterone. Moreover, the natural occurrence of 28-norcastasterone and 28-nortyphasterol in seedlings of A. thaliana has been demonstrated. This is the first report of the natural occurrence of 28-nortyphasterol in plants.

Cells, Cultured↗
PubMed2000

Asymmetric interhemispheric delta waves during all-night sleep in humans.

OBJECTIVE: In order to better understand the asymmetry of brain function during sleep, period-amplitude analysis of delta EEG activity was performed on polysomnograms (PSGs) in normal humans. Twenty healthy, right-handed male volunteers aged 22-35 years (mean age 27.2 years) served as subjects in this study. METHODS: EEGs were recorded from disc electrodes placed at bilateral frontal, central, parietal, occipital, anterotemporal and posterotemporal (10-20 electrode system) sites using A1+A2 for reference. Period-amplitude analysis was performed by the zero-crossing method using the Medilog Sleep Analyzing Computer. RESULTS: Delta counts in the right frontal and central regions during all-night sleep were significantly greater than in those of the left; total delta counts of the right frontal region were greater than those of the left in 18 of the 20 subjects. There were no significant differences in delta counts between the left and right hemispheres in parietal, occipital, anterotemporal, and postero-temporal regions. CONCLUSIONS: These results suggest distinct laterality in the number of delta waves in the frontal and central regions, reflecting functional asymmetry of the brain during sleep.

Adult↗
PubMed2000

Detection of microsatellite alterations in nipple discharge accompanied by breast cancer.

Nipple discharge in breast cancer cases was examined loss of heterozygosity (LOH). DNA samples were extracted from both supernatant and cell pellet components of the discharge, and examined for LOH at microsatellite markers, D11S1818, D11S2000, D16S402, D16S504, D16S518, D17S520, and D17S786. At least one LOH was found in either the supernatant or cell pellet in seven out of 10 patients (70%). Five of seven samples, which were cytologically negative, were LOH positive, and only one case, which was cytologically positive, showed no LOH on the markers examined. All three samples, which were judged 'negative' by CEA measurement (<400 ng/ml), were LOH positive. This method could be a useful novel diagnostic modality for nonpalpable breast cancer with nipple discharge.

Adult↗