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Biomedical subjects

K Okuma

Publications and source records attributed to K Okuma.

At least 19 recordsLinked to original sources
PubMed2004

Series of surveys for enteric viruses and indicator organisms in Tokyo Bay after an event of combined sewer overflow.

Combined sewer overflows (CSOs) have been recognised as one of the serious sources of pollution to the water environment during rain events, although field surveys to investigate the effect of their magnitude and duration on receiving waters have been very limited. The fates of enteric viruses (norovirus G1, G2, enteroviruses) and coliforms were determined in the wastewater treatment plant on a fine day and on a rainy day. Not all microorganisms were reduced in the primary treatment, but were reduced in the secondary treatment. Occurrences of enteric viruses and levels of coliforms were surveyed in the receiving coastal area after a CSO event, with the profiles of the enteric viruses in the coastal seawater being almost at the same positive ratio for 4 d after the CSO event.

Data Collection↗
PubMed2001

TEM and HAADF-STEM study of a Au catalyst supported on a TiO2 nano-rod.

Gold nanoparticles were deposited on TiO2 nano-rods by a deposition precipitation method. This Au/TiO2 nano-rods catalyst is active for CO oxidation even at temperatures less than 273K and is as active as the catalyst of Au supported on conventional TiO2 particles. Transmission electron microscopy (TEM) showed that the TiO2 nano-rods were composed of a single anatase crystal and had a pillar shape with an axis along the <111> direction surrounded by flat four [101] planes. High angle annular dark field scanning TEM (HAADF-STEM) also revealed that a Au platelet with a thickness of 0.5-1 nm was formed at the interface between TiO2 nano-rods. The Au platelet was not observed when conventional round particles of TiO2 were used as a support.

Journal Article↗
PubMed2001

Interleukin 1 polymorphisms, lifestyle factors, and Helicobacter pylori infection.

Associations between Helicobacter pylori (HP) infection and lifestyle factors have been reported by several authors, but little is known about the host factors associated with the infection. This study aims to examine the infection rate of HP according to gene polymorphisms of interleukin (IL)-1A, IL-1B, and IL-1RN, and to investigate the interactions with lifestyle factors. Subjects were 241 non-cancer outpatients who had participated in a HP eradication program. Polymorphisms at - 889 (T to C) of IL-1A, at - 31 (C to T; T allele makes a TATA box) and - 511 (C to T) of IL-1B, and at intron 2 (86-bp VNTR (variable number of tandem repeats)) of IL-1RN were genotyped by PCR (polymerase chain reaction), PCR-RFLP (restriction fragment length polymorphism) and PCR-CTPP (PCR with confronting two-pair primers). It was found that IL-1B polymorphisms at - 31 and - 511 were near-completely linked, but in the opposite way to that in Caucasians; - 31C / - 511T and - 31T / - 511C alleles were dominant in the present subjects. The HP infection rate was substantially different among the genotypes of IL-1B C - 31T; 45.2% (19 / 42) for the C / C, 67.7% (90 / 133) for the C / T, and 63.6% (42 / 66) for the T / T. The age-sex adjusted odds ratio (OR) relative to the C / C genotype was 2.32 (95%CI (confidence interval), 1.10 - 4.92) for the T / C genotype and 2.46 (1.06 - 5.74) for the T / T genotype. The OR for the T / T genotype was significantly modified by smoking status; interaction term = 14.6 (1.12 - 190). The polymorphisms of IL-1A and IL-1RN were not associated with the infection rate. The results suggested that the T allele of IL-1B C - 31T is associated with vulnerability to persistent HP infection, and that the vulnerability is modified by smoking.

Adult↗
PubMed2000

Reaction of selenobenzophenones with olefins. Formation of 1H-2-benzoselenopyrans. Reaction of 1H-2-benzoselenopyrans with diazoalkanes

Selenobenzophenone reacts as a diene with dimethyl acetylenedicarboxylate (DMAD) to lead to dimethyl 1H-1-diphenylmethyl-1-phenyl-2-benzoselenopyran-3,4-dicarboxylate (5c) in moderate yield; the initial [4 + 2] cycloaddition is followed by the addition of another 1 mol equiv of selenobenzophenone. The reaction might proceed through carbene insertion of the primary cycloadduct. On the other hand, 4,4'-dimethoxyselenobenzophenone combines as a diene with DMAD furnishing dimethyl 1H-1-p-methoxyphenyl-6-methoxy-2-benzoselenopyran-3,4-dicarboxylate (4a). The reaction of benzoselenopyran derivative (4) with diaryldiazomethanes afforded another type of carbene insertion product.

Journal Article↗
PubMed2000

No association of the 5' promoter region polymorphism of CYP17 with breast cancer risk in Japan.

To examine the association between breast cancer risk and a T-to-C substitution polymorphism at the 5' promoter region of CYP17, a case-control study was conducted at Aichi Cancer Center Hospital in Japan. Subjects were 144 histologically confirmed breast cancer patients diagnosed in the past 4 years and 166 hospital controls without cancer. Allele frequency among controls was 44.9% (95% confidence interval; 39.5 - 50.2) for C allele. Odds ratio (OR) of the polymorphism relative to TT-genotype was 0.97 (0.58 - 1.64) for TC-genotype and 0.81 (0.39 - 1.68) for CC-genotype. Subgroup analyses revealed that the OR was not statistically significant for the subgroups stratified by interval after diagnosis, age at menarche, age at first birth, menopausal status, body mass index, and mother / sisters' history of breast cancer. Consistent with previous studies conducted in other countries, the 5' promoter region polymorphism of CYP17 affected breast cancer risk of Japanese women to a limited extent. Although this is not a large-scale case-control study with population controls, these findings provide enough information to discourage further studies on the association between this polymorphism and breast cancer risk in Japan at large, and suggest that this polymorphism is useless for breast cancer risk estimation.

Adult↗
PubMed2000

[Antibody levels for diphtheria, tetanus and pertussis in young adult females immunized with whole cell pertussis-diphtheria-tetanus toxoid vaccine in infancy].

Antibody levels for diphtheria, tetanus and pertussis in 84 young adult females were measured. They had been immunized with whole cell pertussis-diphtheria-tetanus toxoid (DTwP) vaccine as a routine immunization in their infancy. Their history of DTwP vaccination were confirmed in their Maternal and Child Health Handbook, which includes their immunization record. Among the 84 cases, 4 cases (4.7%) had been immunized with the first dose of DTwP, 5 cases (6.0%) with the second dose, 23 cases (27.4%) with the third dose and 52 cases (61.9%) with the fourth dose. Of the 84 cases, 89.3% had received DTwP vaccine more than the third dose. In the 15-19 years after the last DTwP vaccination, the antibody positive rate for diphtheria and tetanus (> or = 0.01 IU/ml) were 86.9% and 94.0%, respectively. On the other hand, antibody positive rate for anti-pertussis toxin (anti-PT) and anti-filamentous hemaggulutinin (anti-FHA) (> or = 10 EU/ml) were 35.7% and 55.9%, respectively. The positive rate for pertussis compared with those for diphtheria and tetanus were lower. These findings suggested that DTwP vaccination in infancy does not provide sufficient immunity for young adults against pertussis, but DTwP vaccination provides adequate immunity against diphtheria and tetanus.

Adult↗
PubMed2000

Virus entry is a major determinant of cell tropism of Edmonston and wild-type strains of measles virus as revealed by vesicular stomatitis virus pseudotypes bearing their envelope proteins.

The Edmonston strain of measles virus (MV) that utilizes the human CD46 as the cellular receptor produced cytopathic effects (CPE) in all of the primate cell lines examined. In contrast, the wild-type MV strains isolated in a marmoset B-cell line B95a (the KA and Ichinose strains) replicated and produced CPE in some but not all of the primate lymphoid cell lines. To determine the mechanism underlying this difference in cell tropism, we used a recently developed recombinant vesicular stomatitis virus (VSV) containing as a reporter the green fluorescent protein gene in lieu of the VSV G protein gene (VSVDeltaG*). MV glycoproteins were efficiently incorporated into VSVDeltaG*, producing the VSV pseudotypes. VSVDeltaG* complemented with VSV G protein efficiently infected all of the cell lines tested. The VSV pseudotype bearing the Edmonston hemagglutinin (H) and fusion (F) protein (VSVDeltaG*-EdHF) infected all cell lines in which the Edmonston strain caused CPE, including the rodent cell lines to which the human CD46 gene was stably transfected. The pseudotype bearing the wild-type KA H protein and Edmonston F protein (VSVDeltaG*-KAHF) infected all lymphoid cell lines in which the wild-type MV strains caused CPE as efficiently as VSVDeltaG*-EdHF, but it did not infect any of the cell lines resistant to infection with the KA strain. The results indicate that the difference in cell tropism between these MV strains was largely determined by virus entry, in which the H proteins of respective MV strains play a decisive role.

Animals↗
PubMed2000

Anti-tetanus toxoid antibody production and protection against lethal doses of tetanus toxin in hu-PBL-SCID mice.

BACKGROUND: In this study, severe combined immunodeficiency (SCID) mice, which permit the survival of lymphoid cells of human origin, were used to study the human anti-tetanus immune response. METHODS: Human peripheral blood lymphocytes (hu-PBL) obtained from 88 healthy donors (aged from 18 to 62) were transplanted into SCID mice, and anti-tetanus toxoid (Ttd) antibody production and protection against lethal doses of tetanus toxin (Ttx) were investigated in the hu-PBL-SCID mice. RESULTS: The transfer of human PBL evoked significant human anti-Ttd IgG antibody production for 37.5% of the donors. After in vivo immunization, the percentage of donors with PBL exhibiting positive anti-TtD IgG production in the mice increased to 54.5%. Mean anti-Ttd IgG levels in the sera were also significantly elevated in response to immunization. The mean IgG titer for the mice injected with PBL from donors under the age of 40 was significantly higher than that of the mice injected with PBL from donors aged 40 or older. Four weeks after the cell transfer, the mice were challenged with Ttx. The induction of protection against Ttx challenge was observed mostly in mice with PBL transferred from donors under the age of 40. In vivo immunization in SCID mice with Ttd increased the number of cases of resistance to Ttx. CONCLUSIONS: These results suggest that hu-PBL-SCID mice might serve as a tool for predicting the protective ability against pathogens in PBL donors and also for evaluating vaccine efficacy.

Adolescent↗
PubMed1999

Host range of human T-cell leukemia virus type I analyzed by a cell fusion-dependent reporter gene activation assay.

We constructed a sensitive and quantitative assay system to examine human T-cell leukemia virus type I (HTLV-I) envelope (env) glycoprotein-mediated cell fusion in which T7 RNA polymerase in donor cells coexpressing env glycoproteins activates a reporter gene in recipient cells upon cell fusion. An efficient expression of HTLV-I env glycoproteins (gp46 and gp21) was observed in 293T cells transfected with an expression plasmid by both immunoblot and immunofluorescence analyses. The cells expressing env glycoproteins also exhibited self-fusion. By cocultivating the donor cells with recipient cells transfected with a reporter plasmid possessing the luciferase gene under the T7 promoter, the expression of luciferase was observed upon cell fusion. The activation of the luciferase gene was inhibited by either anti-env neutralizing antibody or synthetic peptide corresponding to env gp21, thus indicating the cell fusion to be specifically mediated by the HTLV-I env glycoproteins expressed in the donor cells. A broad range of cell lines exhibited susceptibility to HTLV-I env-mediated cell fusion by this assay. This newly established assay system may thus provide an efficient way both to study the fusion mechanisms mediated by HTLV-I env glycoproteins and to identify the HTLV-I receptor(s).

Animals↗
PubMed1999

Identification of a novel bovine serum protein which is involved in human T-cell leukemia virus type I (HTLV-I)-induced syncytium formation.

By immunizing rats with cocultured HTLV-I-positive ILT8M2 and HTLV-I-negative MOLT-4-cells, we isolated a monoclonal antibody (mAb), designated as mAb R21, which enhances the syncytium formation induced by coculturing ILT8M2 cells with MOLT-4 cells. The antigen recognized by mAb R21 was found on the surface of all T-cell, fibroblastoid, and epithelial cells lines, and a part of B-cell and myelomonocytoid cell lines. MAb R21 reacted with an approximately 17-kDa protein from ILT8M2 and MOLT-4 cell lysates in both nonreducing and reducing conditions by immunoblotting. Immunoprecipitation experiments using surface-labeled cells revealed that a 17-kDa protein is present on the surface of both ILT8M2 and MOLT-4 cells. Since the enhancing activity by mAb R21 of syncytium formation was observed only in the presence of a factor contained in fetal calf serum (FCS) which seems to bind to mAb R21, we purified this serum factor from FCS using a mAb R21-coupled Sepharose 4B column. The purified protein, designated as R21 protein, was revealed to be O-glycosylated but not N-glycosylated protein of approximately 17 kDa. The partial amino acid sequence of this protein indicates that R21 protein is a novel bovine serum protein which has approximately 90% amino acid homology with bovine platelet factor 4, a member of CXC chemokine family. These results indicate that the R21 protein on the surface of cells and/or in FCS may play an important role in the process of HTLV-I-induced syncytium formation by as yet unknown mechanism.

Amino Acid Sequence↗
PubMed1999

Tea polyphenol intake and changes in serum pepsinogen levels.

Following a phase I study, a phase II study was conducted to evaluate the effects of two different doses of tea polyphenols on serum pepsinogen levels. Subjects were patients aged 40 to 69 years who had undergone gastroscopy between 1995 and 1997 at Aichi Cancer Center Hospital, and had been found to have no disease requiring medication. Those with pepsinogen I < 70 ng/ml and pepsinogen I/II ratio < 6 were included in this study. Capsules containing 100 mg of tea polyphenols were administered for 1 year: 1 capsule per day for 101 patients (42 males and 59 females), and 6 capsules (equivalent to 10 cups) per day for 83 patients (30 males and 53 females). The enrollment of the 1 capsule group preceded that of the 6 capsule group, in which re-participation was allowed. Blood samples were obtained 1 year after participation from 86 participants of the 1 capsule group and 77 participants (43 new participants and 34 re-participants) of the 6 capsule group. The compliance in polyphenol capsule intake ranged from 11.4 to 105.7% (87.6% on average) of the scheduled amount for the 1 capsule group and 3.2 to 112.3% (77.8% on average) for the 6 capsule group. No serious polyphenol-related adverse effects were reported. The difference in pepsinogen I between before and after 1 year intake of the polyphenol was 3.1 ng/ml for the 43 participants of the 6 capsule group, but 3.5 ng/ml for the 1 capsule group. The mean pepsinogen I/II ratio for the 43 participants increased from 2.37 by 0.08. This increase was not larger than that for the 1 capsule group (from 2.61 by 0.11). Among 34 participants in both interventions, no significant increase in pepsinogen I and I/II ratio for the 6 capsule intervention was observed. This result suggests that additional polyphenol intake for 1 year in Japanese does not improve pepsinogen levels, which are considered to reflect stomach atrophy, a high-risk condition for stomach cancer.

Adult↗
PubMed1999

[A case received pre-exposure immunization against rabies by intradermal injection of rabies vaccine because of allergic reaction to the component of the vaccine].

A female, 25 years of age, came to our clinic to receive pre-exposure immunization against rabies. In another hospital she was tested to find out whether she was allergic to the components of rabies vaccine (PCEC) manufactured by the Chemo-Sero-Theraptic Research Institute (Kaketsuken) by cutaneous reaction using a 2,000-fold diluted PCEC. She showed a positive reaction. In our clinic she was again examined by skin test using 0.1 ml of 10-fold diluted PCEC. She showed wheal and flare reaction. Further we tested using 0.05 ml and 0.1 ml of non-diluted PCEC. Her skin reaction did not increase by several mm in diameter. So we decided to immunized her against rabies with intradermal injections of PCEC instead of subcutaneous injections that is indicated by the manufacturer. The second intradermal injections were done to right and left forearms a week later. Then the third shot was given 4 weeks after the second. At 2 weeks after the third injection her blood sample was taken to measure anti-rabies antibody titer by ELISA method with Platelia rabies kit (Diagnostic Pasteur, France). She had 6.7 U/ml of anti-rabies ELISA antibody that was much higher than the protective level (0.5 IU/ml) officially recognized by WHO. Therefore, it is concluded that she had produced sufficiently high level of anti-rabies antibody with intradermal injection of PCEC. It is reasonably recommended to investigate further if the intradermal injection of PCEC will be an effective method as a pre-exposure immunization against rabies.

Adult↗
PubMed1999

Dermatomyositis associated with invasive thymoma.

We report a case of dermatomyositis (DM) associated with invasive thymoma in a 22-year-old woman who was admitted to our hospital complaining of dyspnea which required ventilation support. The reddened elevated scaly eruptions were prominent over the extensor surfaces. Chest X-ray and computed tomography showed mediastinal masses, which were diagnosed as mixed type thymoma. Muscle and skin biopsy specimens were compatible with DM. She was treated with methylprednisolone pulse therapy followed by extended removal of the anterior mediastinal tumor and subsequent radiotherapy. She has had a good clinical course without recurrence of thymoma or DM for more than 3 years. The role of thymoma in the development of DM is discussed.

Adult↗
PubMed1998

Enhancing activity of mycobacterial cell-derived adjuvants on immunogenicity of recombinant human hepatitis B virus vaccine.

In a previous study, we demonstrated that a lipophilic derivative of muramyl dipeptide [MDP-Lys(L18)] augmented antibody response to recombinant human hepatitis B surface antigen (rhHBsAg) when it was co-immunized with rhHBsAg solubilized in PBS. Here, we examined adjuvant activity of two bacterial cell-derived adjuvants such as Bacillus Calmette-Guérin cell wall skeleton (BCG-CWS) and trehalose-6,6'-dimycolate (TDM), to enhance immunogenicity of rhHBsAg, comparing their activity with that of MDP-Lys(L18). In an animal model where mice were immunized subcutaneously (s.c.) with rhHBsAg (25 micrograms/mouse) admixed with 100 micrograms/mouse of BCG-CWS (Vac/BCG-CWS) or 50 micrograms/mouse of TDM (Vac/TDM) in o/w emulsion formulation, both mice immunized with Vac/BCG-CWS and Vac/TDM showed higher antibody titres to HB antigen than those of mice immunized with the recombinant vaccine alone. The activity of BCG-CWS and TDM to enhance antibody induction seemed to be almost the same with that of MDP-Lys(L18). Furthermore, the enhanced antibody response raised by these adjuvants was shown to be due to high titres of HB antigen-specific IgG1. In addition, the activity of these three adjuvants to enhance antibody response was shown to be higher than that of the present clinical vaccine, aluminium hydroxide-attached rhHBsAg (rhHBsAg-alum). In an analysis of delayed-type hypersensitivity (DTH) reaction where mice were immunized with rhHBsAg admixed with or without each adjuvant in o/w emulsion and followed by intrafootpad (i.f.) injection of rhHBsAg 4 weeks after immunization, mice immunized with Vac/BCG-CWS and Vac/TDM as well as Vac/MDP-Lys(L18) showed a significant increment of swelling reaction. These results suggest that BCG-CWS, TDM and MDP-Lys(L18) are potential adjuvants to enhance the immunogenicity of rhHBsAg to induce humoral and cellular responses.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1998

Hydroxypropyl-modified potato starch increases fecal bile acid excretion in rats.

The effects of hydroxypropyl potato starches (HPS) of three different degrees of substitution (DS) on concentration of plasma cholesterol, apparent digestibility of protein, fecal excretion of bile acids, fecal output and cecal pool of organic acids such as acetic, propionic, butyric, lactic and succinic acid were studied in rats in Experiment 1. In Experiment 2, the effects of hydroxypropyl distarch phosphate (HDP) of three different degrees of cross-linking (DC) on the same indexes were studied. Gelatinized potato starch that was not modified chemically (PS) was used as a control. Rats were fed a fiber-free, purified diet containing either HPS, HDP or PS (100 g/kg) for 21 d. In each experiment, fecal output was greater and fecal excretion of bile acids was higher in rats fed the HPS diets with higher DS and the HDP diets compared with control rats fed the PS diet. Apparent protein digestibility in rats fed the HPS diets with higher DS and the HDP diets with higher DC was lower than that in control rats fed the PS diet. The pool size of cecal organic acids was not affected by diet. In Experiment 1, apparent protein digestibility, fecal output and fecal bile acids excretion were significantly correlated with DS (r = -0.994, P = 0.0059; r = 0.976, P = 0.0236; and r = 0.899, P = 0.0077, respectively). The plasma cholesterol concentration was significantly lower in rats fed the HPS diets than in control rats fed the PS diet. The HPS diets resulted in higher proportions of propionic acid, lactic acid and succinic acid and a lower proportion of n-butyric acid than the PS diet. In Experiment 2, apparent protein digestibility was significantly correlated with DSP (r = 0.996, P = 0.0028), which was inversely related to DC. The HDP diets did not affect the plasma cholesterol concentration. The HDP diets resulted in higher proportions of acetic acid, lactic acid and succinic acid and a lower proportion of n-butyric acid than the PS diet. These results suggest that the physiological effects of chemically modified starches are affected by the type of modification.

Animals↗