Search PubMed⌕ Search

Biomedical subjects

T Takasaki

Publications and source records attributed to T Takasaki.

At least 55 records · Page 3Linked to original sources
PubMed1998

Establishment and characterization of Japanese encephalitis virus-specific, human CD4(+) T-cell clones: flavivirus cross-reactivity, protein recognition, and cytotoxic activity.

We analyzed the CD4(+) T-lymphocyte responses of two donors who had received Japanese encephalitis virus (JEV) vaccine 6 or 12 months earlier. Bulk culture proliferation assays showed that peripheral blood mononuclear cells (PBMC) responded to JEV antigens (Ag) but also responded at lower levels to West Nile virus (WNV) and dengue virus type 1, 2, and 4 (D1V, D2V, and D4V, respectively) Ag. Five JEV-specific CD4(+) human T-cell clones and one subclone were established from PBMC of these two donors. Two clones responded to WNV Ag as well as to JEV Ag, whereas the others responded only to JEV Ag. Three of five CD4(+) T-cell clones had JEV-specific cytotoxic activity and recognized E protein. The HLA restriction of the JEV-specific T-cell clones was examined. Three clones were HLA-DR4 restricted, one was HLA-DQ3 restricted, and the HLA restriction of one clone was not determined. T-cell receptor analysis showed that these clones expressed different T-cell receptors, suggesting that they originated from different T lymphocytes. These results indicate that JEV vaccine induces JEV-specific and flavivirus-cross-reactive CD4(+) T lymphocytes and that these T lymphocytes recognize E protein. The functions and HLA restriction patterns of these T lymphocytes are, however, heterogeneous.

CD4-Positive T-Lymphocytes↗
PubMed1998

Establishment and characterization of Epstein-Barr virus-specific human CD4+ T lymphocyte clones.

We developed a simple method for establishing Epstein-Barr virus (EBV)-specific, human CD4+ T cell clones. The method originates from our experience that the regression of cell growth in in vitro EBV transformation of B cells occurs when round lymphoid cells appear in the culture. Peripheral blood mononuclear cells (PBMCs) were cultured with EBV, and IL-2 (20 U/ml) was added to the culture on day 17 after the virus addition. The phenotype of the growing cells was CD3+, CD4+, and CD8-. The cells were cytotoxic for autologous lymphoblastoid B cell line (LCL) and EBV-superinfected autologous LCL. The cytotoxic T lymphocytes (CTLs) were confirmed to be CD4+ T cells but not CD8+ T cells in the culture. CTL clones were established by a limiting dilution method. All the CTL clones had the phenotype of CD3+, CD4+ and CD8-, and proliferated in response to autologous LCL. They produced interferon (IFN)-gamma, interleukin 2 (IL-2) and tumour necrosis factor (TNF)-beta but not IL-4. All but one clone responded to both autologous, EBV-superinfected and non-superinfected LCLs. Proliferative and cytotoxic responses to allogenic LCLs were heterogeneous. These results suggest that this method induces heterogeneous, EBV-specific CD4+ CTL clones and is useful for analysis of CD4+ T cells in EBV infections.

Adult↗
PubMed1998

[The role of endoscopic ultrasonography for gastric cancer in the cardiac area].

In order to select the most appropriate treatment for gastric cancer in the cardiac area, precise staging by determining the depth of cancer invasion, and esophageal invasion, and lymph node metastases is important. In this paper, diagnosis of these factors using endoscopic ultrasonography (EUS) and its accuracy are discussed. In 121 cases of gastric cancer in the cardiac area, EUS was performed and the findings compared with the pathological diagnosis. The depth of cancer invasion was accurately determined in 60% of mucosal cancer cases, 83% of cancer invading the submucosa, 50% of cancer invading the muscularis propria or the subserosa, 86% of cancer invading the serosa, 45% of cancer invading other organs, and overall accuracy was 77%. In cases of esophageal invasion sensitivity was 98%, specificity 93%, and overall accuracy 94%. In cases of lymph node metastasis specificity was 78%: 86% for N1 and 72% for N2. EUS therefore has an important role in diagnosis and selection of treatment.

Cardia↗
PubMed1997

Electron microscopic study of human immunodeficiency virus type 1 (HIV-1) core structure: two RNA strands in the core of mature and budding particles.

The basic structure of human immunodeficiency virus type 1 (HIV-1) has been investigated morphologically; however, the internal structure of HIV-1 core is not well understood. We studied the internal structures by transmission electron microscopy. We modified the method for electron staining of ultrathin sections and processed electron microscopic photographs using a computer. We confirmed that a mature HIV-1 particle had two copies of RNA strands in a cone-shaped core. These two RNA strands formed a coiling structure and interwound each other, and were already present in the late budding stage.

HIV-1↗
PubMed1997

SLE with death from acute massive pulmonary hemorrhage caused by disseminated strongyloidiasis.

We describe a case of disseminated strongyloidiasis involving a female patient with active systemic erythematosus (SLE). The cause of death was massive pulmonary hemorrhage induced by a filariform larvae infection. This was initially diagnosed during examination of the bronchoalveolar lavage fluid just 2 days before her death. The case indicated that immunosuppressed individuals would be paid attention to possible parasitic infection prior to starting therapy even in non-endemic areas as well as other microorganisms.

Acute Disease↗
PubMed1997

Electronmicroscopic study of human herpesvirus 6-infected human T cell lines superinfected with human immunodeficiency virus type 1.

Human herpesvirus 6 (HHV-6) has been proposed as one of the co-factors responsible for the development of acquired immunodeficiency syndrome (AIDS) in human immunodeficiency virus (HIV) carriers. We analyzed the interaction between HHV-6 and HIV-1 in superinfected cells. Cell-free HIV-1 could superinfect human T cell lines, MT-4 and Molt-4, which had been previously infected with HHV-6. Both HHV-1 and HHV-6 replicated in the same cells. We observed two types of morphologically distinguished cells as early as 4 days after superinfection. One type (D) was degenerate cells with intracellular and extracellular HHV-6 and with less HIV-1 virions. The other type (I) was relatively intact cells with both HIV-1 and HHV-6 virions. Replication of HIV-1 was more active in the type I as compared with type D cells. The level of HIV-1 reverse transcriptase (RT) activity in the culture supernatants of cells superinfected on day 0 declined after day 7, while that in the supernatants of cell cultures infected with HIV-1 alone remained high between days 12 and 40. These results suggest that the superinfection of the HHV-6-infected cells with HIV-1 may induce a degenerative process in these cells.

Cell Line, Transformed↗
PubMed1996

Human antibodies responsible for binding inhibition and polymerization inhibition of human immunodeficiency virus type 1 reverse transcriptase.

Using a solid-phase non-radioisotopic (non-RI) reverse transcriptase (RT) assay, antibodies inhibiting human immunodeficiency virus type 1 (HIV-1) RT activity (RTI antibody) were investigated for their ability to inhibit binding of RT to a template-primer and DNA polymerization. The RTI antibody inhibited the binding of RT to the template-primer (BI antibody), and directly reacted with the RT-template-primer complex and inhibited enzymatic activity (PI antibody). The RTI antibody interfered with formation of the RT-template-primer complex suggesting that it recognized the antigenic site involved in template-primer binding of RT molecules. Since deoxynucleotide triphosphates (dNTPs) blocked inhibition of the RT activity by the PI antibody, the antigenic site recognized by the PI antibody may be closely related to the dNTP binding site. The seropositivities of the BI and PI antibodies were 84.6% and 91.2%, respectively, in HIV-1-infected individuals; healthy individuals, HTLV-I-positive individuals, autoimmune disease patients and leukemia patients were all seronegative. No significant correlation of residual RT activities was observed when BI and PI antibodies were compared (r = 0.688). It is possible that the epitopes recognized by the BI antibody differs from those recognized by the PI antibody. The assays described are able to detect BI and PI antibodies in the sera of HIV-1-infected individuals.

Animals↗
PubMed1996

Sharp Increase in the Incidence of Mammary Carcinoma in Kagoshima Prefecture, Japan.

Between 1986 and 1990, among a female population of about 0.95 million, 1184 women living in Kagoshima Prefecture were diagnosed pathologically as having mammary carcinoma. The number of patients with mammary carcinoma, the crude incidence rate per 100000 women and age-standardized mammary carcinoma incidence rates were 205, 21.29 and 19.42 in 1986, 212, 22.04 and 19.48 in 1987, 238, 24.74 and 21.8 in 1988, 245, 25.47 and 22.33 in 1989 and 284, 29.57 and 25.69 in 1990, respectively. The number of patients with this disease increased annually. The increase in the age-specific incidence rate of this type of cancer between 1986 and 1990 was 1.38-fold in women between 40 and 49 years of age, 1.46-fold in women between 50 and 59, 1.37-fold in the 60-69 age group, 1.48-fold in the 70-79 age group and 1.91-fold in women over 80. In both the urban and rural areas, the incidence increased annually during the course of this study. In 1990, the age-standardized mammary carcinoma incidence rate in urban area was 1.17 times that in rural area.

Journal Article↗
PubMed1996

Inhibitory effects of selenium, vitamin A and butylated hydroxytoluene on growth of human maxillary cancer cells in vitro.

The effects of vitamin A, selenium, and butylated hydroxytoluene (BHT) on the growth of a human maxillary cancer cell line were examined in monolayer cell cultures. The colony-forming assay showed a 50% reduction in the survival rate of the cell line at a concentration of 3.6 micrograms/ml of selenium, 28 micrograms/ml of vitamin A, and 74 micrograms/ml of BHT. Flow cytometric analysis with both FITC-labeled bromodeoxyuridine monoclonal antibody and propidium iodide demonstrated an increase of the S-phase fraction in the presence of selenium, an increase of the G0/G1-phase fraction in the presence of vitamin A, and an increase of the G2-M-phase fraction 1 day followed by an increase of G0/G1-phase fraction from the 3rd to 7th day when BHT was added. These results suggest that the mechanisms of inhibition of DNA synthesis by these compounds are different.

Antibodies, Monoclonal↗
PubMed1996

Recurrent laryngeal papillomatosis developing into laryngeal carcinoma with human papilloma virus (HPV) type 18: a case report.

We report a case of recurrent laryngeal papillomatosis which developed into laryngeal squamous cell carcinoma 11 years after the first diagnosis. Interestingly, we could identify HPV type 18 DNA in the carcinoma tissue using the polymerase chain reaction (PCR). Other known risk factors of irradiation, smoking, exposure to chemical agents, or a hereditary tendency to malignant tumours were not present in this case. Our finding suggests that HPV type 18 is another aetiological agent for laryngeal carcinoma.

Carcinoma, Squamous Cell↗
PubMed1996

Retrospective survey of chronic Q fever in Japan by using PCR to detect Coxiella burnetii DNA in paraffin-embedded clinical samples.

We used PCR to detect Coxiella burnetii DNA in paraffin-embedded tissues obtained from patients with chronic endocarditis in which the etiological agent had been unknown. On the basis of the published nucleotide sequence of the C. burnetii htpB gene, primers were chosen to produce an amplified fragment of 285 bp. A total of 60 samples from 56 patients were tested for the presence of C. burnetii DNA. Five samples from four patients were found to be positive. All of the amplified DNA fragments possessed a TthHB8I restriction site, as predicted from the published sequence of C. burnetii. In one of the four positive patients, rickettsia-like particles were found in sections of tissue stained by Gimenez's method. This is the first report of chronic Q fever in Japan.

Base Sequence↗
PubMed1996

[Clinical usefulness of trans-brachial angiography for abdominal diseases].

Trans-brachial angiography for abdominal disease has several advantages for the patient. For example, the patient can walk immediately following angiography and can return home or eat in the sitting position after examination. We performed trans-brachial angiography on 451 cases of abdominal disease from June 1992 to March 1995. The purpose of performing angiography in 215 of these cases was examination only, while that in the remaining 236 cases was embolization of liver tumor. Four hundred and five cases were used for the study of safety and accuracy, and the remaining 46 cases as well as another 51 cases of trans-femoral angiography were used for the study of technical difficulty. Based on these experience, we have concluded that trans-brachial angiography for abdominal disease is highly useful, safe and accurate, and can provide significant advantages for patients requiring abdominal angiography.

Adult↗
PubMed1995

Inhibitory effects of selenium, vitamin A and butylated hydroxytoluene on in vitro growth of human tongue cancer cells.

The effects of vitamin A, selenium and butylated hydroxytoluene (BHT) on the growth of a human tongue cancer cell line were examined in monolayer cell cultures. A colony-forming assay showed a 50% reduction in the survival rate of the cell line at a concentration of 2.6 micrograms/ml selenium, 60 micrograms/ml vitamin A and/or 38 micrograms/ml BHT. Relatively low concentrations of selenium markedly inhibited glucose consumption. Flow cytometric analysis with both fluorescein-isothiocyanate-labelled bromodeoxyuridine monoclonal antibody and propidium iodide demonstrated an increase in S-phase fractions 1 day after the addition of selenium, increased G0/G1 phase fractions in the presence of vitamin A and increased G2-M phase fractions when BHT was added. These results suggest that these compounds inhibit DNA synthesis of in vitro human tongue cancer cells by different mechanisms.

Butylated Hydroxytoluene↗
PubMed1995

Conversion of cathepsin E to enzymatic unstable form in gastric cancer cells.

A new acid proteinase in human gastric cancer, named medium moving proteinase (Med.P), was found also in a gastric cancer transplanted into nude mouse. However, Med.P disappeared when the samples prepared from gastric cancer tissues were left for over 4 weeks at -80 degrees C, whereas the activity of cathepsin E (CE) increased. When these samples were reduced by dithiothreitol (DTT), Med.P appeared again and the CE activity decreased. These phenomena, revealed by electrophoretic analyses, indicated that Med.P is a monomeric form of CE (mono-CE). At weakly alkaline pH and after heating, mono-CE appeared to be more unstable than CE. These results indicated that CE assume an enzymatically unstable monomeric form in cancer cells.

Animals↗
PubMed1994

Expression of p53 protein in benign epithelial hyperplasia, atypical ductal hyperplasia, non-invasive and invasive mammary carcinoma: an immunohistochemical study.

To clarify whether p53 protein expression is involved in multistep carcinogenesis or the progression of mammary ductal carcinoma, we investigated p53 protein expression in 83 invasive ductal carcinomas (IDC), 10 IDC with a predominant intraductal component, 13 non-invasive ductal carcinoma (NIDC), 16 atypical ductal hyperplasia (ADH) and 39 benign epithelial hyperplasia (EH), using immunohistochemistry. Expression of p53 protein was detected in 24 (28.9%) cases of IDC, 5 (50%) cases of IDC with a predominant intraductal component and 1 (7.6%) case of NIDC. No expression was observed in either ADH or EH. In IDC, including cases with a predominant intraductal component, p53 protein expression was associated with a higher histological grade (P < 0.0001) or mitotic index (P < 0.0005). Although overexpression of c-erbB-2 protein has also shown a similar association with these prognostic indicators, expression of p53 protein correlated regardless of the status of c-erbB-2 overexpression. Completely coordinated expression of p53 protein was seen in both intraductal and invasive components. The intraductal component in IDC including cases with a predominant intraductal component which expresses p53 protein had significantly higher histological grade (P < 0.0005) or more comedo-subtypes (P < 0.0001). These results suggested that p53 protein expression occurs at a stage of NIDC with high histological grade or in comedo-subtypes. Its expression is maintained throughout invasion.

Breast↗