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T Ota

Publications and source records attributed to T Ota.

At least 253 records · Page 14Linked to original sources
PubMed1990

Isolation and identification of the gene of cholesterol oxidase from Brevibacterium sterolicum ATCC 21387, a widely used enzyme in clinical analysis.

The gene coding cholesterol oxidase (CHOD) from Brevibacterium sterolicum, which is widely used in clinical analysis, has been selected from pUC19-based gene bank in E. coli MM294 by colony-hybridization using synthetic DNA as probe. The gene was identified to encode the protein having the same amino acid sequence as that determined from amino-acid sequence analysis. The expression of the CHOD gene in E. coli was not observed, probably due to the transcription failure. Attempts are being made to express it in various hosts including Streptomyces lividans, Corynebacterium glutamicum, and B. sterolicum itself.

Amino Acid Sequence↗
PubMed1990

A case of coexisting malignant carcinoid tumor and adenocarcinoma in the papilla of Vater.

A 47-year-old Japanese woman in whom obstructive jaundice had already been diagnosed, was found to have a dome-shaped elevated tumor approximately 3 cm in diameter located in the area very close to the papilla of Vater on endoscopical and radiographical investigations. Histopathologically, the resected tumor was composed mainly of solid nests of atypical argyrophilic cells, and partially of an area of well differentiated tubular adenocarcinoma, showing mutual transition in the mucosal layer. Both immunohistochemical and ultrastructural analyses confirmed the difference in character of tumor cells between these two areas: neuroendocrine cell carcinoma and tubular adenocarcinoma of common type in the intestine. To the best of our knowledge, this is only the third case reported to be a coexisting malignant carcinoid tumor and adenocarcinoma arising in the periampullary region.

Adenocarcinoma↗
PubMed1990

Positive Darwinian selection promotes charge profile diversity in the antigen-binding cleft of class I major-histocompatibility-complex molecules.

Certain major-histocompatibility-complex (MHC) loci are highly polymorphic, and the mechanism of maintenance of this polymorphism remains controversial. Recent studies of the pattern of nucleotide substitution at MHC loci have produced strong evidence that this polymorphism is maintained mainly by positive Darwinian selection that operates on the antigen recognition site (ARS) of the MHC molecule. The ARS of the class I MHC consists of three subregions: (1) the binding cleft, (2) T-cell-receptor-directed residues, and (3) outward-directed residues. Here we report that the rate of nonsynonymous nucleotide substitution is much higher in the binding cleft than in the other ARS subregions. Furthermore, nonsynonymous nucleotide substitutions that result in a change of residue side-chain charge occur significantly more frequently than expected by chance. We conclude that the main target of positive selection on the class I MHC molecules is the binding cleft of the ARS and that this selection acts primarily to promote diversity among alleles with respect to the pattern of residue side-chain charges (charge profile) in the binding cleft. These results provide additional support for the hypothesis that MHC polymorphism is maintained by overdominant selection relating to antigen-binding capacity and thus to disease resistance.

Alleles↗
PubMed1990

Carbonic anhydrase II gene expression in cell lines from human pancreatic adenocarcinoma.

Current evidence suggests that carbonic anhydrase II (CA II) is produced by pancreatic duct cells but not by pancreatic acinar or islet cells. The aim of this study was to determine whether CA II homologous RNA and CA II immunoreactive protein are produced by cell lines established from human pancreatic adenocarcinomas. A 1.7-Kb CA II homologous RNA was detected in poly(A+) RNA isolated from normal human pancreas, normal human liver, and to varying degrees in the cell lines examined. The CA II immunoreactivity corresponding to approximately 30 kD (consistent with the established molecular mass of CA II) was also detected by immunoblotting in normal human pancreas, normal human liver, and some of the cell lines. We also found that the levels of CA II homologous RNA increase in the pancreatic adenocarcinoma cell lines following treatment with the differentiating agent, retinoic acid.

Adenocarcinoma↗
PubMed1990

Beta-2-microglobulin generation rate and clearance rate in maintenance hemodialysis patients.

We analyzed the rebound pattern of plasma beta 2-microglobulin (beta 2-m) concentration from 4 h after completion of hemodiafiltration until the start of the next treatment according to the one-pool beta 2-m kinetic model so as to determine beta 2-m generation rate and whole-body beta 2-m clearance. Next, we obtained the whole renal beta 2-m clearance as the product of renal creatinine clearance and the glomerular sieving coefficient of beta 2-m. Then, extrarenal beta 2-m clearance was calculated as the difference between whole-body beta 2-m clearance and whole renal beta 2-m clearance and renal beta 2-m clearance due to tubular absorption was taken to be the difference between whole renal beta 2-m clearance and renal beta 2-m clearance due to urinary excretion. The results showed that the higher the patients' plasma beta 2-m concentration was, the lower was the whole-body beta 2-m clearance. Moreover, in the present study, an inverse correlation was found between the following respective factors: plasma beta 2-m concentration and whole renal beta 2-m clearance; plasma concentration and renal clearance due to tubular absorption; plasma concentration and renal clearance due to urinary excretion. However, there was no correlation between plasma beta 2-m concentration and extrarenal beta 2-m clearance. The findings indicate that the variation of plasma beta 2-m concentration with the individual patient is solely attributable to the variation in residual renal function in terms of beta 2-m elimination.

Adult↗
PubMed1990

Analysis of immunologic mechanisms of high natural killer cell activity in tuberculous pleural effusions.

We found natural killer (NK) activity to be high in tuberculous pleural effusions from which Mycobacterium tuberculosis was cultured. In this study, we investigated and compared the mechanisms of this NK activity in tuberculous pleural effusions and peripheral blood. Cytotoxicity was augmented in tuberculous pleural effusion mononuclear cells (PEMNC) and peripheral blood mononuclear cells (PBMNC) by culture with purified protein derivative (PPD). Prior to culture with PPD, there were many more interleukin-2 receptors (IL-2R, p55) on Leu 11+ (CD16+) cells in tuberculous PEMNC than in tuberculous PBMNC. After 5 days of culture with PPD, the numbers of IL-2R increased in both PEMNC and PBMNC. PPD-induced cytotoxicity was inhibited by the addition of anti-IL-2R monoclonal antibody (anti-IL-2R mAb). Interferon-gamma (IFN-gamma) production was abundant in the supernatants of cultured tuberculous PEMNC and PBMNC, but very little interleukin-2 (IL-2) and IFN-alpha and -beta were produced. Considerably more IFN-gamma was produced in tuberculous PEMNC than in tuberculous PBMNC, and PPD-induced cytotoxicity was inhibited by anti-IFN-gamma monoclonal antibody (anti-IFN-gamma mAb). Cell surface analysis after PPD-induced cytotoxicity was performed by complement-mediated cytolysis. Leu 11+ cells exhibited essential cytotoxicity in the induction and effector phases, but neither OKT4+ (CD4+) nor OKT8+ (CD8+) cells displayed such cytotoxicity. These data suggest that Leu 11+ cells in tuberculous PEMNC are activated by M. tuberculosis through IFN-gamma and that IL-2R plays an important role in the activation of NK cells.

Adult↗
PubMed1990

[Establishment and characterization of human cholaginocarcinoma, MEC, producing carbohydrate antigen 19-9].

A new tumor cell line MEC was established from pleural effusion of a patient of cholaginocarcinoma. In tissue culture, the cell line grew in the sheet of variant cells and showed the epithelial-like pattern. Histologically, the cell line almost showed the same pattern as those in bile and preural effusion from the patient. Electron microscopic observation of this cell line showed the irregular microvilli on the surface of the cell and the desmosome between cells. The doubling time of the cell line was 40.8 hours. Chromosome counts ranged from 61 to 86. The cell line had 9 marker chromosomes and some variant chromosomes. The cell line was transplanted into the subcutaneous of nude mice and formed the tumor. It showed the moderately differentiated tubular adenocarcinoma the same pattern as the primary tumor. We have recognized the producing and releasing of CA19-9 in the serum from the tumor bearing nude mouse and supernate of the medium as the serum from the patient. The presentation of CA19-9 in the cytosol of the cell line and the tumor cells of nude mouse was recognized in Avidin-Biotin-Peroxidase Complex in immunoloperoxidase techniques. The cell line can grow in serum-free medium. On September, 1990, the cell line has been maintained from 70 passages during about 800 days.

Adenoma, Bile Duct↗
PubMed1990

[Characteristic difference of functional tricuspid regurgitation between acquired valvular heart disease and atrial septal defect].

The characteristic difference in functional tricuspid regurgitation (TR) was studied between acquired valvular heart disease (VHD) and adult atrial septal defect (ASD). Fifty patients of VHD and 20 patients of ASD were subjected to this study. In all patients, the TR volume per beat (VTR) was calculated with our original method using 2-dimensional color Doppler (2-DD) and continuous-wave Doppler (CW) echocardiographies. VTR is obtained by the product of the cross-sectional areas (S) of the base of regurgitant jet in 2-DD and the regurgitant volume of one unit area (Vu) in CW (VTR = 1/3.S.Vu). The preoperative evaluation of TR according to VTR showed a good relationship with the operative findings, and the patients with preoperative VTR greater than or equal to 10 cc were candidates for tricuspid valve repair. In all patients with preoperative VTR less than 10 cc (18 patients of VHD and 10 patients of ASD), VTR decreased postoperatively without any tricuspid valve repair. In patients with VTR = 10-20 cc (19 patients of VHD and 5 of ASD), VTR showed a decrease to below 10 cc after tricuspid annuloplasty (TAP) by Kay's method in 18 patients of VHD and 5 of ASD, and with no tricuspid valve repair in one patient of VHD. In patients with VTR greater than or equal to 20 cc (13 patients of VHD and 5 of ASD), the postoperative VTR diminished to below 10 cc after Kay's TAP in 8 patients of VHD and 5 of ASD, and VTR disappeared after valve replacement (TVR) in 2 patients of VHD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Surgical treatment of valvular heart disease associated with Behçet's disease].

We experienced two patients of valvular heart disease associated with Behçet's disease. First patient presented aortic regurgitation (AR) due to perforation of left coronary cusp of the aortic valve and underwent valve replacement (AVR). Second patient showed AR due to shortening of the aortic valve along with mitral regurgitation caused by dilatation of the annulus, and received AVR as well as mitral annuloplasty by Kay's method. Each patient has been doing well for 5 and 2 years after operation, respectively. Patients with Behçet's disease often have perivalvular leakage after valve replacement. We treated our patients as follows to prevent this serious postoperative complication. 1. The operation was performed when the inflammatory signs and findings subsided with enough adrenal steroids. 2. At operation, the prosthetic valve of one size smaller than the size considered suitable was selected for valve replacement. 3. The adrenal steroids have been continuously administrated and adjusted according to the values of CRP and ESR as well as the cutaneous and mucous manifestations of this disease.

Adult↗
PubMed1989

Strong anti-tumor effect of monosialoganglioside specific monoclonal antibody 202: a clinical trial in a cancer patient with melanoma.

Mab 202, a mouse monoclonal IgM antibody which recognizes sialic acid alpha 2----3 galactosyl residue in monosialogangliosides and reacts with human melanoma cells but not with normal cells, was administered to a melanoma patient by either intralesional injection or intravenous infusion. Mab 202 induced regressions of the metastatic tumors without side effects. Histopathologic examination showed remarkable degenerative and necrotic changes in the tumor, around which lymphocytes, eosinophils, plasma cells and macrophages infiltrated. Immunoperoxidase staining revealed Mab 202 binding to melanoma cells. Clinical and pathologic evidence suggested that Mab 202 has cytotoxic effects against melanoma cells. Mab 202 may therefore be useful in the treatment of human malignant melanoma.

Antibodies, Monoclonal↗
PubMed1989

Binding position of phenylbutazone with bovine serum albumin determined by measuring nuclear magnetic resonance relaxation time.

The binding of phenylbutazone (PB) to bovine serum albumin (BSA) was considered to be predominantly due to hydrophobic interaction based on the thermodynamic parameters obtained by an equilibrium dialysis method. Little variation of proton nuclear magnetic resonance (1H-NMR) chemical shift of PB was found with change in the concentration of PB (0.5-5 mM) or upon the addition of BSA (7.25 x 10(-5) M). The NMR spectrum of PB in 0.1 M phosphate buffer solution at pH 7 showed that PB existed as a mesomeric anion. The spin-lattice relaxation time (T1) of PB was almost concentration-independent, but decreased in the presence of BSA to 36-38% for the phenyl group and 48-100% for the butyl group. The spin-spin relaxation time (T2) of PB was also almost independent of concentration, but was remarkably decreased in the presence of BSA to ca. 2.5% for the phenyl group and ca. 6-9% for the butyl group. The ratios of the spin-spin relaxation rate (1/T2) of the free PB to that of the bound PB were ca. 5000-11000 for the butyl group and ca. 23000 for the phenyl group. The binding of PB to BSA was considered to involve primarily the phenyl group.

Animals↗
PubMed1989

[Induction of phenotypic reverse transformation by plant glycosides in cultured cancer cells].

Crude ginsenosides extracted from the root of Panax ginseng C.A. Meyer inhibited the growth and colony forming ability of Morris hepatoma cells in soft agar suspension culture, and stimulate the serum protein synthesis of these cells, thus converting the cell characteristics both functionally and morphologically to those resembling original normal liver cells. We have called such a phenomenon "reverse transformation" or "redifferentiation" which can be regarded as decarcinogenesis. In this report, the results of our recent investigations are presented with particular reference to reverse transformation of B16 melanoma cells induced by ginsenoside Rh2 isolated from the methanol extract of crude ginseng saponin fraction and action mechanisms of ginsenoside Rh2 are also discussed.

Cell Differentiation↗
PubMed1989

[Surgical treatment of acute aortic dissection].

Sixty-seven patients subjected to this study composed of 32 patients treated surgically, 15 patients treated medically and 20 patients examined by autopsy for the past 8 years. Out of 32 surgical cases, 16 were operated on in an acute stage, within 2 weeks after onset and 9 out of these 16 acute cases belonged to DeBakey type I or II and 11 out of 15 autopsy cases belonged to type I or II either. Contrarily most of the medical cases were type III. Both causes of death in the acute autopsy group and operative indications in the acute surgical group were cardiac tamponade, heart failure due to aortic insufficiency, myocardial infarction and aortic rupture. Operative mortality rate was 12.5% in the acute cases and 19% in the chronic cases, late mortality rate was 19% in the acute cases and 0% in the chronic cases. Two cases of operative death had massive bleeding due to aortic rupture and massive myocardial infarction. These were the most dangerous complications of acute aortic dissections. We conclude that all patients with type I or II dissections should be operated on before fatal complications occur.

Acute Disease↗
PubMed1989

[Closure of patent ductus arteriosus in elderly cases].

A technique for closure of patent ductus arteriosus in the elderly cases is described. We have operated on eleven adult cases of patent ductus arteriosus cases in 10 years. In five cases cardiopulmonary bypass used and in the other six cases it was not used. The cardiopulmonary bypass was used especially for the patients with pulmonary hypertension (pulmonary artery mean pressure greater than 40 mmHg), or high aged (older than 40 years) patients. No operative death have occurred in both groups, and no complication from air embolism or hemorrhage have been encountered. The technique embodies the profound hypothermia, low flow, and direct suture of the pulmonary end of the ductus arterious through a pulmonary arteriotomy. The ductus has been obstructed by using a Hegar's dilator before core cooling was started. Hegar's dilator is useful for establishing profound hypothermia and satisfactory visualization of the operative field.

Adult↗
PubMed1988

Production of B cell-stimulating factors by B cells in patients with systemic lupus erythematosus.

The production of B cell-stimulating factors (BSF) by B cells in patients with systemic lupus erythematosus (SLE) was studied in vitro. B cells from SLE patients markedly proliferated and differentiated into Ig-producing cells by in vitro culture without any stimulation. The culture supernatant of these B cells contained BSF activity that stimulated Staphylococcus aureus Cowan I-treated normal B cells to proliferate and differentiate into Ig-producing cells. By a Percoll gradient density centrifugation, BSF-producing cells were enriched in the higher density fraction, but were reduced in the lower density fraction. The BSF also stimulated the proliferation and the differentiation of SLE B cells. By a Percoll gradient density centrifugation, SLE B cells responsive to the BSF were enriched in the higher density fraction, but were reduced in the lower density fraction. The Mr of the BSF was estimated as about 18,000 Da by Sephacryl S-200 column chromatography. The BSF fraction did not possess IL-2 and IFN activity, but possessed IL-1 activity, which stimulated murine thymocyte proliferative responses. The BSF activity was partially, but not completely, absorbed by an anti-IL-1 alpha antibody. Furthermore, the BSF possessed IL-4 activity, which induced not only the proliferative responses of normal B cells stimulated with B cell mitogens, but also the expression of low affinity Fc epsilon R/CD23 on normal B cells. The BSF also possessed IL-6 activity, which induced the proliferative responses of IL-6-dependent hybridoma cells, MH-60 BSF2. Moreover, human rIL-1, rIL-4, and rIL-6 stimulated SLE B cells. These results suggest that SLE B cells spontaneously produce the BSF such as IL-1 alpha, IL-4, and IL-6 and express their receptors on their surface, and the interaction between the BSF and their receptors stimulates SLE B cells to spontaneously proliferate and differentiate into Ig-producing cells as an autocrine mechanism.

Animals↗
PubMed1988

Inhibitory effect of anti-class II antibodies on human B-cell activation.

The role of class II antigens for B-cell activation was analyzed using purified human B cells and anti-class II monoclonal antibodies. The stimulation of purified B cells with Staphylococcus aureus Cowan I induced proliferation and differentiation into immunoglobulin-producing cells in the presence of interleukin-1 and T-cell-derived factors (B-cell growth factor and B-cell differentiation factor). The addition of anti-class II monoclonal antibodies inhibited B-cell responses. However, anti-class I monoclonal antibody did not inhibit B-cell responses. When mitomycin C and cycloheximide-treated B cells were added to the induction culture of B cells as the stimulator, B-cell responses were enhanced in a dose-dependent manner. Furthermore, the stimulator B cells also partially restored the suppressed B-cell responses which were induced by the pretreatment of B cells with anti-class II antibody. This enhancing effect of stimulator B cells on B-cell responses was inhibited by the pretreatment of stimulator B cells with anti-class II antibody. The treatment of B cells with anti-class II antibody and complement depleted the activity of both responder B cells and stimulator B cells. These results suggest that cellular interaction among B cells exists in the B-cell activation induced with Staphylococcus aureus, Cowan I and anti-class II antibody inhibits B-cell activation by interfering in this cellular interaction.

B-Lymphocytes↗