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Biomedical subjects

H Tada

Publications and source records attributed to H Tada.

At least 325 records · Page 18Linked to original sources
PubMed1990

Regulation of the human neurotropic virus promoter by JCV-T antigen and HIV-1 tat protein.

We compared the ability of HIV-1 tat protein and JCV T-antigen in inducing transcription from the JCV late promoter, JCVL. A JCVL promoter-chloramphenicol acetyltransferase plasmid (pJCL-CAT) was transfected into human glial cells alone or together with plasmids producing T-antigen and tat protein. CAT enzyme activity obtained from the transfected cells indicated that both JCV T-antigen and HIV-1 tat proteins stimulated JCV late gene expression. However, the level of induction mediated by tat protein was significantly higher than that obtained with T-antigen. Moreover, in contrast to JCV T-antigen, tat stimulated JCVL-promoter activity over a narrow range of ptat expressor plasmid concentration. Co-transfection of both T-antigen and tat plasmids at optimal concentrations resulted in greater than additive CAT activity from the JCVL promoter. This synergism suggests that the two activator proteins utilize alternative mechanisms to exert their effects. Using deletion mutations from the 5' end of the JCVL promoter, we demonstrated that different regions within the JCV enhancer/promoter are important for T-antigen and tat induction, implying that these activators function through distinct targets to increase JCVL promoter activity.

Antigens, Polyomavirus Transforming↗
PubMed1989

Increased intraglomerular thrombin formation in diabetic microangiopathy.

Estimations of soluble fibrin monomer complexes (SFMC) in plasma are a convenient index of thrombin activation. Renal venous-arterial differences in plasma SFMC concentrations were determined in 16 randomly chosen diabetic patients by sampling directly and simultaneously from the renal artery and vein according to the method of Seldinger. In all subjects, SFMC concentrations were higher in the renal vein than in the renal artery, indicating that the kidney is an important source of SFMC. Venous-arterial differences were markedly elevated in patients with severe renal and retinal microangiopathy coupled with hypertension. The hypothesis is advanced that elevated plasma SFMC levels lead to abnormal fibrin deposits in lesioned glomeruli and retinal vessels. It is postulated that plasma SFMC may be a useful parameter for the assessment of diabetic vascular complications.

Adult↗
PubMed1989

Regulation of JCVL promoter function: transactivation of JCVL promoter by JCV and SV40 early proteins.

To better understand the basis of cell type specificity of JCV replication, we have analyzed the expression of the viral late promoter in glial cells. Using transient transfection procedures, we show that the late gene expression, like that of the early gene, is restricted to glial cells. However, cotransfection with a plasmid producing the JCV early protein, T-antigen, stimulates expression from the JCV late promoter in both glial and non-glial cells. The SV40-encoded T-antigen acts similarly on transcription of JCV late promoter in both cell types. This transacting effect occurs at the level of RNA synthesis, as measured by the rate of transcription, stability of the message, and translation. These results indicate that basal JCV late promoter activity is restricted to glial cells, whereas in the presence of viral early protein this promoter functions in both glial and non-glial cells.

Antigens, Polyomavirus Transforming↗
PubMed1989

An enzyme immunoassay for human lymphotoxin.

A highly sensitive and specific enzyme immunoassay (EIA) for human lymphotoxin (hLT) has been developed. The assay is based upon a sandwich system employing two kinds of anti-hLT antibodies with neutralizing activity. One of them was mouse monoclonal antibody raised against Escherichia coli-derived recombinant hLT with a deletion of 20 amino-terminal amino acids and used as labelled antibody. The other was rabbit antibody raised against the carboxyl-terminal portion of hLT and used as solid-phase antibody. The EIA employing such a combination was able to detect less than 50 pg/ml of hLT, showing that this method was approximately 5-10 times higher sensitivity than the conventional bioassay employing L929 cell-lysis. The mean recovery of hLT added to serum specimens was 101% and the coefficients of variation were 3.3-7.8% (intra-assay) and 2.9-17.2% (interassay). There was a good correlation between the present EIA and the bioassay (r = 0.93).

Animals↗
PubMed1989

Bispecific antibody-producing hybrid hybridoma and its use in one-step immunoassays for human lymphotoxin.

A hybrid hybridoma cell line secreting a bispecific monoclonal antibody (MAb) was constructed by fusing horseradish peroxidase (HRPO)-immunized mouse splenocytes with previously established mouse hybridomas secreting anti-human lymphotoxin (hLT). This cell line was grown in ascitic fluid in mice to obtain large quantities of hybrid MAbs and a bispecific antibody, reacting with both HRPO and hLT, was separated from the monospecific antibody or other inactive immunoglobulin populations by hydroxylapatite chromatography. Sodium dodecylsulfate-polyacrylamide gel electrophoresis demonstrated that the bispecific antibody molecule contained two different types of heavy and light chains of both anti-HRPO and anti-hLT origin. The bispecific antibody was used to establish one-step enzyme immunoassays (EIAs) employing competitive and sandwich systems. The simple sandwich EIA was able to detect 1-100 U/ml of hLT and there was good correlation (r = 0.96) between hLT concentrations measured by the one-step EIA and a bioassay using L929 cell-lysis.

Antibodies, Monoclonal↗
PubMed1989

Influence of food on bioavailability from two controlled-release granules of theophylline.

The bioavailability and absorption pattern of theophylline from Theolong granule and Theodur-G were studied in five healthy volunteers both in fasting conditions and after taking two different meals. In all the subjects, no dose-dumping effect was observed with a standard- or a fat-rich breakfast on these preparations. Postprandial administration delayed the absorption of theophylline and a fat-rich breakfast significantly reduced the area under the curve (AUC0-26) for both preparations. The mean AUC decreased by 14.0% for the former and 19.7% for the latter when the fat-rich breakfast was administered. Intake of a standard breakfast resulted in a decrease in the AUC0-26 by 10.6% for Theolong granules but there was little effect observed with the Theodur-G granules.

Adult↗
PubMed1989

Prevention of vertical transmission of hepatitis B virus by yeast recombinant hepatitis B vaccine.

In order to prevent vertical transmission of hepatitis B virus (HBV), yeast recombinant HB vaccine at a dose of either 5 mcg or 10 mcg was administered to 185 infants born to mothers who were positive for HBs antigen (HBsAg). All of them developed antibody to HBsAg (anti-HBs) after three vaccinations. Generally, the cut-off index (COI) of anti-HBs by radioimmunoassay (RIA) was higher in the 10 mcg dosage group than in the 5 mcg dosage group. The geometric mean titer (GMT) of anti-HBs, as measured by quantitative RIA, in the former group was 2.4 times that in the latter one month after the third vaccination. The incidence of clinical reactions was only 4% in a total of 561 injections, and none of the reactions were severe. It is concluded that recombinant HB vaccine is safe and has excellent immunogenicity for infants requiring prevention of HBV vertical transmission. It is also suggested that 10 mcg doses of the recombinant HB vaccine can provide more solid protection to high-risk infants without serious adverse reactions.

Carrier State↗
PubMed1989

Cell type-specific expression of JC virus early promoter is determined by positive and negative regulation.

We analyzed control sequences of the human papovavirus JC virus (JCV) to define the cis-acting elements that regulate specific expression of the viral early region genes in glial cells. Nuclear run-on transcription, S1 analysis, and chloramphenicol acetyltransferase enzyme activity in a transient transfection assay established that the cell type-specific expression of JCV early genes is determined at the transcriptional level. Using DNase footprinting analysis of nuclear proteins prepared from glial and nonglial cells, we located four regions within the JCV control sequences that specifically interacted with the proteins. In glial cells, all four domains contributed to the specific expression of a heterologous promoter, whereas in nonglial cells, two protein-binding regions showed no effect on basal transcriptional activity and the other two domains significantly downregulated transcription of the promoter. We conclude that cell type-specific transcription of the JCV early promoter is under both positive and negative regulation in eucaryotic cells.

Base Sequence↗
PubMed1989

Annular lesion of the lung in sarcoidosis.

A 20 year old man presented with eight thin walled, ring shaped shadows, 1-3 cm in diameter, on a chest radiograph. Pulmonary sarcoidosis was diagnosed on the basis of histopathological examination of a cervical lymph node, transbronchial lung biopsy, and increased activity of angiotensin converting enzyme and lysozyme in serum. The lesions disappeared within six months of his starting corticosteroid treatment.

Adult↗
PubMed1989

Preparation of zein microspheres conjugated with antitumor drugs available for selective cancer chemotherapy and development of a simple colorimetric determination of drugs in microspheres.

Zein microspheres conjugated with antitumor drugs (mitomycinc (MMC), daunomycin hydrochloride (DM), peplomycin sulfate (PEP] were prepared by using a dimethyl sulfoxide (DMSO)-H2O system. MMC with low solubility in H2O was easily entrapped by the standard procedure, whereas some modifications were required for moderately and highly soluble drugs such as DM and PEP. Colorimetric determination of the drugs in microspheres was easily achieved by use of the phenol-sulfuric acid method for drugs with sugar moieties in their molecules, such as DM and PEP, while a simple treatment of the microspheres with concentrated sulfuric acid was applied in the case of drugs having a chromophore in their molecules, such as DM and MMC.

Antineoplastic Agents↗
PubMed1989

[Evaluation of hydroxyapatite implants in human periodontal osseous defects].

In this clinical study we evaluated the use of hydroxyapatite ceramic (HAP) implant in conjunction with the surgical treatment of periodontal osseous defects. Fifty-five defects in 23 patients were treated and filled with HAP particles (BDHAP-101). At 6 months and 12 months after the placement of particles, the sites were evaluated by gingival margin heights, periodontal pocket depths, attachment levels, tooth mobility, the gingival index (GI), and radiographic analyses. Oral hygiene status was estimated by the plaque index (PlI). There were significant improvements with regard to probe depth, attachment level, tooth mobility, and GI. The radiographic analysis showed a similar density of the adjacent bone and the particles, suggesting excellent biocompatibility. There were no changes in PlI before or after the placement of implants.

Bone Resorption↗
PubMed1989

Identification of binding protein of virginiae butanolide C, an autoregulator in virginiamycin production, from Streptomyces virginiae.

In Streptomyces virginiae, production of virginiamycin is triggered by signal molecules named virginiae butanolide A, B or C (VB-A, B or C: Yamada, Y. et al. J. Antibiotics 40: 496-504, 1987). We have found a specific VB-C binding protein from S. virginiae, and characterized it by using a tritium-labeled VB-C analogue as a ligand. By equilibrium dialysis in the absence and presence of radio-inert VB-C, a crude extract from 1 g of wet mycelia specifically bound 3.5 pmol of [3H]VB. The binding disappeared after pronase digestion and showed ligand specificity toward cis VB-C (cis VB-C greater than trans VB-C much greater than A-factor type), indicating that binding was due to a cis VB-C specific binding protein. Scatchard analysis of the binding demonstrated a single class of high affinity binding sites (Kd 1.1 nM) and low number of the binding sites (30-40 sites/genome DNA). By gel filtration on Sephadex G-75 and molecular sieve HPLC, the binding protein was shown to have an Mr of about 20,000. These results indicate that the substance is a novel VB-C binding protein and suggest that it is a VB-receptor mediating the pleiotropic signal transmitted by VBs in S. virginiae.

4-Butyrolactone↗
PubMed1989

[Evaluation of plasma PIVKA-II as a new marker for hepatocellular carcinoma].

We have measured the plasma PIVKA-II levels in 188 cases of various liver disease with HCC and malignant diseases in other organs by an EIA, using a monoclonal antibody (E-1023 kit, Eisai), and also have measured the plasma vitamin K levels in cases of HCC and cholestasis by an HPLC. Plasma PIVKA-II was detected in many cases of HCC (67%, 35 of 52 cases) and cholestasis (60%, 6 of 10 cases). In contrast, the positivities of PIVKA-II in the other diseases including benign liver diseases were very low. Combination assays of PIVKA-II and vitamin K revealed that PIVKA-II correlates with vitamin K in cholestasis but not in HCC, suggesting that PIVKA-II in HCC does not depend on a systemic deficiency of vitamin K. From these results, it was concluded that PIVKA-II is a reliable marker which can reflect the clinical course of HCC.

Adult↗