Biomedical subjects
Publications and source records attributed to T Kanai.
We experimentally demonstrate that by longitudinally pumping 2 mm long molybdenum preformed plasma with high-intensity 475 fs duration laser pulse, a highly directive soft-x-ray laser at 18.9 nm wavelength is generated. The divergence of the beam is evaluated to be of the submilliradian order, and only requires a pump laser energy of 150 mJ.
Harmonic generation from solid surface plasmas is studied using a subpicosecond Nd:glass laser system. For a 45 degrees angle of incidence, the speculars up to the fifth harmonics are blue shifted when the laser intensity exceeds 2 x 10(16) W cm(-2). The second harmonic is blueshifted by approximately 16 A, and the fifth harmonic is blue shifted by approximately 51 A for p polarization at the intensity of 1 x 10(17) W cm(-2). We observed the blue shift of the fifth harmonics and found that the magnitude of blue shift is higher compared with that for the second harmonics. The blue shift is interpreted as a collisionless absorption due to the anomalous skin effect. It is also found that the divergence of harmonics preserves a smaller divergence when using a shorter pulse length for the driving laser.
p27 is regarded as a cyclin-dependent kinase inhibitor of the G1-to-S cell cycle progression by suppressing the kinase activity of cyclin/cyclin-dependent kinase complex. This study aimed to investigate p27 expression in the normal endometrium and endometrioid adenocarcinoma of the uterine corpus and the correlation of its expression with cell proliferation and clinicopathological parameters. Tissue samples of 127 endometrioid adenocarcinomas and 15 normal endometria were used in the study. Immunohistochemical staining for detecting p27 and Ki-67 was performed by the labelled streptavidin-biotin method on formalin-fixed and paraffin-embedded tissue samples. The expression was given as the labelling index, which indicates the percentage of positive nuclei. p27 staining was observed in the nuclei of the glandular cells in the functional layer of the secretory phase endometrium, whereas it was negative in those of the proliferative phase. In endometrioid adenocarcinomas, the labelling index of p27 expression paradoxically increased more significantly in the higher histological grades and was correlated with that of Ki-67. The high level of p27 expression was associated with clinicopathological parameters such as FIGO stage, lymph node metastasis, lymphovascular space involvement and myometrial invasion. High p27 expression was linked to higher grades of endometrioid adenocarcinoma, cell proliferation and some clinical prognostic factors. These results indicate that p27 might be an indicator of poor prognosis.
Single event spectra of a clinical carbon beam have been measured by an ultra-miniature tissue-equivalent proportional counter (UMC). In order to cover the energy range of the Bragg peak, the incident energy of the carbon beam was degraded by aluminium plates. Single event spectra for carbon-events incident to the UMC were analysed and selected at several carbon energies using thin scintillation counters. It was found that the dose weighted lineal energy distributions have a doublet peak structure due to incident carbon beam and fragment contributions.
We report that a positron can act as a probe to directly reveal electronic structures of nanocrystalline embedded particles in materials. The Fermi surface (FS) of "bcc" Cu nanoparticles in an Fe matrix is observed as the first example. A two-dimensional angular correlation of the positron annihilation radiation (2D-ACAR) method is used to measure the momentum distribution which reflects the FS topology. The obtained 2D-ACAR spectra show strong and characteristic anisotropy associated with the necks of the FS around the [110] Brillouin zone boundaries of the bcc Cu, which are well reproduced by full-potential linearized argumented plane-wave calculations.
We established a novel and convenient method to construct a ura3 strain (ura3/ura3) of the asporogenous and diploid yeast, Candida tropicalis, that produces dicarboxylic acid. One copy of the URA3 gene was disrupted using a mutated hygromycin B resistance gene (HYG#). The obtained hygromycin-resistant strain was further transformed with a URA3 disruption cassette and selected on a plate containing 5-fluoroorotic acid. The obtained strains were analyzed and the disruption of the gene was confirmed by PCR and Southern blot analysis. The results showed that the strains were obtained in which allelic URA3 genes were simultaneously disrupted. Furthermore, we established a cotransformation method for this gene disruption, using HYG# in C. tropicalis. In order to disrupt the allelic POX4 genes (encoding acyl-CoA oxidase) of dicarboxylic acid-producing strains, the ARS plasmid (which contained HYG#) and a POX4 disruption cassette (which carried the LAC4 gene encoding beta-galactosidase of Kluyveromyces lactis) were simultaneously introduced by transformation. As a result, the allelic POX4 gene was successfully disrupted.
The synthesis of dicarboxylic acids (DCAs) in Candida tropicalis is thought to be induced by a decrease in fatty acyl-CoA-oxidase activity. However, in the present study we demonstrate that repression of the POX4 gene, encoding fatty acyl-CoA oxidase, does not directly lead to high-level production of DCAs. No fatty acyl-CoA-oxidase activity was detected if the POX4 gene of C. tropicalis strain 1098 (wild-type strain) was disrupted. Furthermore, introduction of the POX4 gene from C. tropicalis strain M1210A3, which is a mutant derived from strain 1098 and is used as an industrial DCA-producing strain, still exhibited low-level fatty acyl-CoA-oxidase activity. Nevertheless, production of DCA was not observed in either case. Furthermore, the increase in acyl-CoA-oxidase activity by expression of the POX4 gene in strain M1210A3 did not reduce high-level production of DCA. These results suggest that alterations in acyl-CoA-oxidase activity are not necessarily related to production of DCA in industrial DCA-producing C. tropicalis M1210A3.
PROBLEM AND METHOD OF STUDY: We have shown that Tokishakuyaku-san (Toki) and Sairei-to (Sai) enhance T helper-1 (Th1) cytokine release from peripheral blood mononuclear cells (PBMCs): thereby, they could be a therapeutic means in the treatment of autoimmunity related recurrent abortion in which T helper-2 (Th2) polarization is exaggerated, the condition purported to benefit from these herbal medicines. However, an open question is whether these medicines might enhance Th1 cytokine release in decidual tissues and thereby stimulate the killer activity, thus, working counterproductively by accelerating maternal alloimmune reactions toward fetal tissues. To address this, we examined the effects of these medicines on the release of cytokines from decidual mononuclear cells (DMCs) in comparison with PBMCs on the assumption that they might act differently on these cell types. The effects of these medicines were investigated as related to human leukocyte antigen (HLA)-G, a nonclassical HLA class I antigen expressed on trophoblasts and a putative crucial player involved in fetomaternal immune interplay. RESULTS: Regarding Th1 cytokines. Toki marginally increased the release of tumor necrosis factor (TNF)-alpha, but not interferon (IFN)-gamma from DMCs while Sai did not affect the release of both. Both Toki and Sai were without effect in modulating the release of interleukin (IL)-4, a member of Th2 cytokines. Interestingly, the presence of HLA-G reduced the release of Th1 cytokines from DMCs regardless of the addition of Toki, Sai or none. These findings are in sharp contrast with PBMCs on which these medicines seem to act so as to enhance Th1 polarization and attenuate Th2 polarization. CONCLUSION: Differential effects of Toki and Sai on the release of Th1/Th2 cytokines between DMCs and PBMCs may afford the rationale of these medicines in the treatment of autoimmunity-related recurrent abortion.
BACKGROUND AND AIMS: Autoimmune responses against colonic epithelium may play a role in the development of colonic inflammation associated with ulcerative colitis (UC). In this study, we established and characterized B-cell lines and clones that produced anticolon antibody from inflamed colonic mucosa of UC subjects. METHODS: B-cell lines were generated through Epstein-Barr virus transformation of lamina propria lymphocytes (LPLs) from colonic mucosa and peripheral blood lymphocytes, and these lines were screened for the production of anticolon antibodies. B-cell lines were then cloned by limiting dilution culture, and messenger RNA expression of immunoglobulin heavy-chain variable region (V(H)) was assessed. RESULTS: V(H) gene families used in B-cell lines established from LPLs of normal controls were diverse, and B-cell lines from UC LPLs expressed a restricted V(H)3 family usage. All 15 clones from UC used a restricted V(H)3 gene family, whereas diverse V(H) gene families were used by 24 clones from normal controls. The analysis of nucleotide sequences indicated that these clones were derived from various germline gene segments. CONCLUSIONS: The restricted V(H) gene usage in anticolon autoantibodies producing B-cell clones suggests that a particular antigenic stimulus contributes to the pathogenesis of UC.
BACKGROUND & AIMS: Crohn's disease (CD) is associated with an increased number of infiltrating macrophages, which release a variety of proinflammatory cytokines. Interleukin (IL)-18 has been implicated in the modulation of mucosal CD4(+) T cells towards Th1 responses, which are implicated in the pathogenesis of CD. Here we assess the role of macrophages and of IL-18 in the murine model of intestinal inflammation that mimics the immunologic characteristics of human CD. METHODS: Colitis was induced in C57BL/6 mice immunized with 2,4,6-trinitrobenzene sulfonic acid (TNBS) followed by rectal administration of TNBS in ethanol. Mice were treated with either an antibody directed against macrophages conjugated to the ribosome-inactivating protein saporin (anti-Mac-1-saporin) or with a neutralizing antibody against IL-18. In addition, we assessed whether an identical TNBS immunization/challenge protocol could induce colitis in IL-18(-/-) mice. RESULTS: The colonic mucosa of TNBS-treated mice was marked by infiltration of Mac-1-positive macrophages and up-regulation of IL-18. The administration of the anti-Mac-1-saporin antibody or the neutralizing anti-IL-18 antibody resulted in a dramatic attenuation of mucosal inflammation in this model. In addition, TNBS was unable to induce significant colitis in the IL-18(-/-) mice. CONCLUSIONS: Our data underscore the pivotal role of macrophages, and the macrophage-derived IL-18, in the establishment of TNBS-induced colitis in mice. Our results highlight the potential use of therapy directed against IL-18 in the treatment of patients with CD.
Exquisitely regulated cytokine balance during early pregnancy is thought to be necessary for promoting survival of the fetal allograft. Our previous studies have demonstrated that membrane-bound human leukocyte antigen (mHLA-G) expressed on trophoblasts is one of the key factors in regulating cytokine balance by shifting the Th1/Th2 balance toward Th2 polarization, a favourable milieu for the maintenance of pregnancy. Given that trophoblasts secrete soluble HLA-G (sHLA-G), we examined its biological roles in comparison with mHLA-G. We cultured peripheral blood mononuclear cells (PBMC) with either the HLA-A and -B-deficient B lymphoblast cell line (721.221 cells) or the same cell line transfected with mHLA-G (721.221-G1 cells), in the presence or absence of recombinant sHLA-G. Cytokine concentrations in the culture media were determined by enzyme-linked immunosorbent assay. In contrast to mHLA-G protein, sHLA-G stimulated the release of tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma, whereas it reduced the release of interleukin (IL)-3, regardless of the presence of the presence of a stimulatory effect of the mHLA-G-expressing cells. Although mHLA-G reduced the release of IL-4, sHLA-G did not have any effect. Conversely, sHLA-G stimulated the release of IL-10 whereas mHLA-G was without effect. These results suggest that sHLA-G regulates the release of cytokines from PBMC chiefly by counterbalancing mHLA-G, and thereby may play a role in maintaining pregnancy.
Recurrence of hepatocellular carcinoma (HCC) is frequent, even after apparently curative resection. Preoperative transcatheter arterial chemoembolization (TAE) does not improve disease-free survival after hepatic resection. We previously reported the potential usefulness of transarterial immunoembolization (TIE), a newly developed arterial embolization technique using OK-432 and fibrinogen, as preoperative treatment. In this study, we further investigated the effect of TIE by histologic examination of the resected specimens and compared it with conventional TAE in a prospective nonrandomized manner. Thirty-nine patients underwent TIE (n = 17) or TAE (n = 22) before curative hepatectomy for HCC. Transarterial immunoembolization was performed according to the standard protocol using OK-432, fibrinogen, and thrombin. Histologic changes in cancerous and noncancerous liver tissues were examined at different stages after TIE. Histologic grading of cancer cell injury according to the modified Shimosato criteria (Grades 0-IV, in increasing order of severity of cell injury) and postoperative disease-free survival were compared between the two groups. Based on the results of histopathology, TAE was more effective than TIE against the main tumor. In contrast, TIE was significantly more effective than TAE against extracapsular invasion and intrahepatic metastasis. Disease-free survival after hepatectomy tended to be better in patients pretreated with TIE than TAE. Postoperative tumor recurrences in the TIE group (n = 4) occurred in the nontreatment regions, whereas tumor recurrences in TAE group developed mostly (8 of 11 patients) in treated liver regions. Based on results of histologic examination, TIE seems to be more effective than conventional TAE against extracapsular invasion and intrahepatic metastasis. Data for disease-free survival and recurrence site suggest TIE may be a useful preoperative treatment.
We established a mouse rising dbl quote, left (low)primary tumor resection model" in which a transplanted tumor was resected after an orthotopic transplantation of colorectal cancer tissue to estimate the therapeutic effect of an angiogenesis inhibitor on metastasis. The angiogenesis inhibitor FR-118487 is a member of the fumagillin family. Here, 1 mg / kg / day of FR-118487 was subcutaneously administered to nude mice for 1 week, 2 weeks, or 4 weeks through an osmotic pump. Liver metastasis developed in 7 of 9 control mice, 2 of 6 mice that underwent the tumor resection 2 weeks after transplantation (early resection), and in all 7 of the mice that underwent the tumor resection 4 weeks after transplantation (late resection). In the short treatment trial, the FR-118487 administration immediately after the early resection completely inhibited both hepatic and peritoneal metastases, whereas its administration after the late resection had no effect on liver metastasis. In the prolonged treatment trial, inhibitory effects of prolonged treatment with FR-118487 on both hepatic and peritoneal metastases after the late resection were clearly demonstrated. The mice of the resection-alone group all died within 106 days after tumor inoculation, due to metastases of colon carcinoma. In contrast, half of the mice that underwent resection and then received antiangiogenic therapy were alive at the end of the observation period (160 days after transplantation). In conclusion, the combination of surgery and subsequent antiangiogenic therapy may be useful to prevent the distant metastasis of colorectal cancer and to improve the prognosis of patients with colorectal cancer.
PROBLEM: To better understand the role of human leukocyte antigen (HLA)-G in regulating the T helper (Th)1/Th2 cytokine balance, one of key conditions in determining the fate of pregnancy, we asked whether the presence of HLA-G protein altered the release of cytokines from both decidual mononuclear cells and peripheral blood mononuclear cells (PBMCs). METHOD OF STUDY: The amounts of cytokines released from decidual mononuclear cells and PBMCs were compared in the presence or absence of HLA-G-expressing cells. RESULTS: When cocultured with HLA-G-expressing cells, the amounts of tumor necrosis factor-alpha and interferon-gamma released from decidual mononuclear cells and PBMCs were decreased, while the amounts of interleukin (IL)-4 from PBMCs was increased, with IL-4 release from decidual mononuclear cells being unchanged. CONCLUSIONS: Upon contact with HLA-G, decidual mononuclear cells, and PBMCs as well, modulate their ability to release cytokines in a way that may shift the Th1/Th2 balance towards relative Th2 dominance, suggesting a role for HLA-G in maintaining pregnancy.
PROBLEM: The aim of this study was to investigate the gene frequencies and shared alleles of human leukocyte antigen (HLA)-E gene in Japanese couples with or without recurrent abortion. METHOD OF STUDY: Polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis was carried out to detect polymorphism in exon 3 of the HLA-E gene in 30 Japanese couples with recurrent abortion and 38 normal Japanese couples with proven fertility. RESULTS: No point mutation was detected in exon 3 of HLA-E in both recurrent aborters and normal controls. HLA-EG and HLA-ER alleles were detected with frequencies of 66.7% and 33.3% in couples with recurrent abortion and 69.2% and 30.8 in normal couples, respectively. The gene frequency of HLA-EG was higher than that of HLA-ER, which is contrary to that found in Caucasian, African-American and Hispanic people but similar to Chinese people. The frequency of each allele was not significantly different between recurrent aborters and normal controls. The number of shared alleles between each couple with recurrent abortion is not significantly different from that with normal controls. CONCLUSION: Allele frequencies of HLA-E were suggested to be different in Asian people from those in other ethnic people. In light of no specific distribution pattern in recurrent aborters, HLA-E polymorphism does not seem to play a role in the pathogenesis of recurrent abortion.
The etiology and pathogenesis of inflammatory bowel disease remains an area under intense investigation. Crohn's disease (CD) is characterized by a marked accumulation of activated Th1 type CD4+ T cells and macrophages in inflamed intestinal mucosa. IL-18 is a recently described cytokine that mainly exists in activated macrophages and shares biological activities with IL-12 in driving the development of Th1 type CD4+ T cells by inducing interferon-gamma. To clarify the role of IL-18 in intestinal inflammation in CD, we assessed the functional role of IL-18 in regulating intestinal mucosal lymphocytes in human CD and murine CD model.
As an attempt to elucidate the factor(s) responsible for the poor performance of a copper(II)-phthalocyanine aminopropylsilica gels (CU-PCSD) column for HPLC, the silanol and/or amino groups remaining on Cu-PCSD were endcapped with trimethylchlorosilane (TMCS) or N-trimethylsilylimidazole (TMSI). The trimethylsilylated Cu-PCS(D)S (Cu-PCSD-TMCS and -TMSI) were investigated concerning their performance as an HPLC-stationary phase in the separation of pi-electron-rich polyaromatic hydrocarbons (PAHs), such as mutagenic anthracene and pyrene. As a result, trimethylsilylation with TMSI, which reacts only with silanol-groups, was not effective to improve the column efficiency. In contrast, trimethylsilylation by TMCS, which reacts with both the silanol- and amino-groups, improved the theoretical plate numbers (N) for PAHs separation with the Cu-PCS(D) column, indicating that the low N values on the Cu-PCSD column were caused by electrostatic interactions between PAHs and the remaining amino-groups on Cu-PCS(D). Furthermore, the retention data of mutagenic heterocyclic amines (HCAs) indicated that the remaining amino groups interact with the polar groups of HCAs.
Carbon beam radiotherapy for cancer patients was initiated in Japan in June 1994. This study attempts to clarify the radiobiological effects of heavy ion beams. In this study, human cancer cell lines (RMG-1, MDA-MB231) and V79 cells were used. The cell killing was determined by colony forming assay, and mutation induction was determined by counting the number of 6-thioguanine resistant colonies (hprt locus mutation assay). The cell lines were irradiated with carbon (20 or 80 keV/microm) or neon beams (80 keV/microm). Carbon ions with a higher LET value (80 keV/microm) had an enhanced cytotoxic effect compared to those with a lower LET value (20 keV/microm). Carbon beams produced a slightly stronger cytotoxic effect than neon beams when irradiated at the same LET level (80 keV/microm), but the difference was not remarkable. The mutant fraction was significantly higher in all cell lines when they were irradiated with heavy ion beams, compared to the results for X-ray irradiation. The mutant fraction increased when the LET of the carbon beams increased. At equivalent LET values, the mutant fraction was lower for neon beams than for carbon beams. Fractionation of carbon beam irradiation had no effect on survival, but reduced the mutant fraction. Neon beams might be more appropriate for heavy ion therapy, especially when higher doses are being used. In addition, the fractionation of heavy ion beam administration might be appropriate for reducing the mutant fraction.