PubMed Health⌕ Search

Biomedical subjects

N Tada

Publications and source records attributed to N Tada.

At least 19 recordsLinked to original sources
PubMed1992

Production and characterization of two monoclonal antibodies to human glutathione peroxidase.

Glutathione peroxidase (GSH-Px) is an important selenium-containing enzyme which protects cells from oxidative damage. Two hybridoma clones (GPX-121 and GPX-347), producing mouse IgG1 monoclonal antibodies specific for GSH-Px, were established. Immunoblot analysis revealed that GPX-347 was specific for human GSH-Px, while GPX-121 cross-reacted with human, rat, mouse and rabbit GSH-Px. Correlation between GSH-Px content and its enzymatic activity was investigated in erythrocytes of 76 humans and in human lung adenocarcinoma PC-9 cells by using a sandwich type ELISA. The results indicated that GSH-Px activity was expressed higher than expected from GSH-Px content especially in the range of low GSH-Px concentration. PC-9 cells selenium depleted medium did not stain but the cytoplasm of PC-9 cells grown in medium supplemented with selenium stained strongly.

Adenocarcinoma↗
PubMed1992

Isolation and characterization of a mouse protein C cDNA.

Protein C (PC) is a vitamin K-dependent serine protease, a deficiency of which results in thrombus. There is no spontaneously occurring mouse model of the disease. Attempts to create such a model in mice by using anti-sense gene technology requires isolation of a normal mouse PC cDNA. When a mouse liver (BALB/c) cDNA library was screened using a human PC cDNA as a probe, nine overlapping cDNA clones were isolated and sequenced. The cloned mouse PC cDNA comprised 1,512 nucleotides and the open reading frame of the cDNA encoded a polypeptide of 461 amino acids residues including a leader peptide composed of 41 amino acids. Mouse PC exhibited high homology to both human and bovine PCs. Mouse PC also had several structural features common in other PCs; locations of 23 Cys residues, location of putative beta-hydroxy Asp71, possible carbohydrate attachment sites involving Asp residues at amino acid positions 249, 314, and 330, and location of active sites such as His212, Asp258, and Ser361. Northern blot hybridization analysis identified a single species of mouse PC mRNA (2.0 kb in length) in mouse liver.

Amino Acid Sequence↗
PubMed1992

A case of CREST syndrome with rapidly progressive liver damage.

A patient with CREST syndrome (calcinosis cutis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia) who had severe jaundice (total bilirubin 29.1 mg/dl) and rapidly progressive liver damage is reported. The liver damage findings matched the criteria of autoimmune chronic active hepatitis (CAH). There have been no prior reports of a case of CREST syndrome with autoimmune CAH in Japan. Anticentromere antibody (ACA) was detected in the serum; ACA seemed to be related to the pathogenesis of these two diseases.

Autoantibodies↗
PubMed1992

Effect of hyperlipidemic serum on cultured mesangial cells.

Hyperlipidemia may contribute to the progression of focal glomerular sclerosis (FGS) in humans and obese Zucker rats. Zucker rats undergo an increase in their plasma low density lipoprotein (LDL), very low density lipoprotein (VLDL) and oxidized lipids, resulting in the development of FGS. We examined the effects of such hyperlipidemic serum on thymidine uptake into cultured mesangial cells. LDL and VLDL both stimulated the overnight uptake of 3H-thymidine at a concentration of below 10 micrograms/ml and inhibited this uptake at over 50 micrograms/ml in the medium. Modified LDL and VLDL after oxidation, however, inhibited this uptake at a concentration of 1 microgram/ml in the medium. Although 20% serum-containing medium stimulated the thymidine uptake by the mesangial cells, the lipoprotein fraction inhibited the uptake, while the lipoprotein-free fraction markedly stimulated it. We conclude therefore that the lipoproteins in hyperlipidemic serum suppress and the lipoprotein-free fraction stimulates mesangial growth. Both may play a role in the development of FGS in rats.

Animals↗
PubMed1992

Protective effect of probucol on ischemia-reperfusion arrhythmias in the rat heart.

OBJECTIVE: To evaluate the efficacy of probucol on ischemia-reperfusion injury in the isolated working rat heart. DESIGN: Twelve male Sprague-Dawley rats were divided into two groups: one was fed normal chow (group C) and the other was fed chow containing 1% probucol for four weeks (group P). Samples of heart organ and blood were then taken under anesthesia. Isolated hearts were perfused in a working heart model. After 5 mins of perfusion in aerobic conditions, global ischemia was induced for 15 mins, the hearts were then reperfused. Aortic and coronary flow, cardiac function and electrocardiogram were monitored throughout the experiment, including a 20 min period of reperfusion. Serum lipids and lipid peroxide were also measured in each rat. RESULTS: Rats in group P (probucol-treated) had significantly lower levels of serum cholesterol, triglyceride and phospholipid than those in group C (controls). Serum lipid peroxide was also significantly lower in group P than in group C rats (P < 0.05). The incidence of ventricular arrhythmias in the ischemia and reperfusion stages was lower in group P than in group C (P < 0.001) and the increase in coronary flow during the reperfusion stage was greater in isolated hearts of group P rats than in those of group C (P < 0.05). CONCLUSIONS: Probucol may have a protective effect on myocardium with respect to ischemia-reperfusion arrhythmia in the isolated rat heart, presumably due to an antioxidative effect.

Animals↗
PubMed1991

Ischemia-reperfusion arrhythmias and lipids: effect of human high- and low-density lipoproteins on reperfusion arrhythmias.

The effect of high- and low-density lipoproteins separated from human serum on the postischemic reperfusion arrhythmias was investigated. The hearts were perfused by working heart mode with Krebs Henseleit bicarbonate buffer containing arachidonic acid (1 microgram/ml) for 5 minutes. Whole heart ischemia was induced by the use of a one-way ball valve, and hearts were perfused for 15 minutes followed by 20 minutes of reperfusion. Physiologic concentrations of high- and low-density lipoproteins were constantly infused through the atrial route during ischemic perfusion. Coronary effluent was collected via pulmonary artery cannulation for subsequent radioimmunoassay of thromboxane B2 and 6-keto-prostaglandin F1 alpha, the major stable metabolites of thromboxane A2 and prostacyclin, respectively. The incidence of ventricular arrhythmias during reperfusion was 6/6 (100%), 1/6 (17%), and 6/6 (100%) in control, high-density lipoprotein and low-density lipoprotein infusion groups, respectively. There was no significant difference in coronary flow among the three groups throughout the perfusion. Both thromboxane B2 and 6-keto-prostaglandin F1 alpha increased significantly during ischemia compared with preischemic values in all groups of hearts. However, the ratio of these two parameters varied in control and low-density lipoprotein infusion groups during ischemia, while there was no significant change in the high-density lipoprotein infusion group. These results provide the possibility that arachidonate metabolites may be involved in the regulation of ischemia-reperfusion arrhythmias and that high-density lipoprotein that was infused during ischemia markedly inhibits the incidence of ischemia-reperfusion-induced ventricular arrhythmias, due in part at least, to stabilizing the arachidonate metabolites during ischemic perfusion.

Animals↗
PubMed1991

The influence of soft lining materials on pressure distribution.

Several soft lining materials are available at present that differ in physical and mechanical properties. To examine the feasibility of soft lining materials used as so-called "tissue conditioners," the properties of soft lining materials were investigated by using a static creep test and a pressure distribution test. Six typical materials were used. The pressure on the testing plate was distributed uniformly on the soft lining materials. The soft lining material acted as a cushion for the external forces. However, the variation of pressures increased with time in the cases of Hydro-cast and Softone materials, but decreased with time in the case of Coe-comfort material.

Dental Materials↗
PubMed1991

[Separation of high density lipoprotein (HDL) using anti-apo A-I, apo A-II immuno-affinity chromatography to evaluate the effects of probucol].

An assessment has been made regarding the changes of the particles of lipoprotein A-I without A-II (Lp A-I) and lipoprotein A-I with A-II (LpA-I/A-II) which correspond to HDL subfraction isolated by the use of anti-apo A-I and A-II antibody affinity columns in order to quantitatively and qualitatively investigate the change of HDL caused by administration of probucol and pravastatin which are therapeutic drugs for hypercholesterolemia. Probucol caused significant decreases of HDL-cholesterol, plasma apo A-I/apo A-II ratio and particles larger in diameter than 10.4 nm. Comparing Lp A-I and A-I/A-II ratios with those in normolipidemic controls and the ratios before and after administration of probucol, the decrease of LpA-I ratio was found to be remarkable after prolonged administration of probucol, and it was presumed that the decrease of HDL cholesterol by prolonged administration reflects the decrease of LpA-I particles more than the decrease of LpA-I/A-II. On the other hand, no significant change was seen in HDL cholesterol, plasma apo A-I/apo A-II ratio or HDL particle size in the pravastatin group. It is considered essential to observe HDL from the aspect of apoprotein, which plays an important role in the metabolism of lipoprotein, in the assessment of the anti-atherogenic activity of HDL cholesterol in future. In other words, it is necessary to analyze the change of HDL from the aspect of Lp A-I and Lp A-I/AII and investigate their respective metabolisms and roles.

Adult↗
PubMed1991

[Prospective controlled study of elective sclerotherapy plus oral propranolol for prevention of recurrent bleeding in cirrhotics with recent variceal hemorrhage].

In a prospective, randomized controlled trial, 43 patients with cirrhosis and variceal hemorrhage were allocated after control of the bleeding to treat by elective sclerotherapy alone (n = 23) or by oral propranolol after elective sclerotherapy (n = 20). The dose of oral propranolol was based on a reduction of the resting pulse rate by 25%. The end points of the study were rebleeding or death. Both treatment groups were comparable with respect to origin and severity of liver disease, size of esophageal varices and portal pressure at entry. The mean follow up was 27 +/- 19 months for all patients. Patients treated sclerotherapy alone had more rebleeding (n = 11) did than those in the sclerotherapy plus propranolol (n = 3). The cumulative percentages of patients free of rebleeding 1 and 2 years after inclusion were 77 and 66% in sclerotherapy alone, and 100 and 85% in sclerotherapy plus propranolol; the difference between the two groups was significant. No statistically significant effect on mortality was seen. These data support that oral propranolol after sclerotherapy reduces the risk of recurrent bleeding in cirrhotics treated elective sclerotherapy.

Administration, Oral↗
PubMed1990

Monoclonal antibodies to disialogangliosides: characterization of antibody-mediated cytotoxicity against human melanoma and neuroblastoma cells in vitro.

We previously reported the binding specificities of two anti-ganglioside GD2 murine monoclonal antibodies (MAbs), A1-425 and A1-267, both of which are of IgG3 isotype. A1-425 reacts specifically with ganglioside GD2, whereas A1-267 binds preferentially to GD2 but also reacts with GD3 [Tai, T., Kawashima, I., Tada, N., & Dairiki, K. (1988) J. Biochem. 103, 682-687]. In this paper, they were used for comparative analyses of antibody-mediated cytotoxicity, i.e., antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against human melanoma and neuroblastoma cell lines. Melanoma cells were found to contain GD2 and/or GD3, whereas neuroblastoma cells expressed only GD2. Both antibodies induced high levels of ADCC and CDC to GD2/GD3-positive cells with human peripheral large granular lymphocytes (LGL) as effector cells and in the presence of human serum, respectively. A good correlation was obtained between the contents of disialogangliosides and the binding level of the antibodies; both melanoma and neuroblastoma cells with larger amounts of GD2/GD3 showed a higher level of antibody binding than did the cells with a smaller amount of GD2/GD3. Surprisingly, ADCC did not correlate well with the binding level of the antibodies. Thus, A1-425 showed stronger lytic activity than A1-267 in spite of the binding level of A1-425 being similar to or lower than that of A1-267 on the cell surfaces. Antigen-antibody complexes composed of GD2 and A1-425 showed higher binding levels to LGL than complexes of GD2 and A1-267. In contrast, free MAb molecules gave minimum binding to LGL.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Rectal carcinoid tumor metastasizing to the thyroid and pancreas. An autopsy case exploiting immunohistochemistry for differentiation from tumors involving multiple endocrine organs.

A 58-year-old male patient with rectal carcinoid tumor is presented. The tumor extensively involved the lymph nodes and liver, and multiple tumors were also recognized in the pancreas and thyroid. Grossly, it was uncertain whether the latter were metastases from the rectal carcinoid or all were coincident primary tumors involving multiple endocrine organs, so-called multiple endocrine neoplasia (MEN) syndrome. Histologic, histochemical and electron microscopic examinations of the tumors in both the pancreas and thyroid showed similar features to those of the rectal carcinoid. The neoplastic cells in all involved organs commonly expressed positive immunoreactivity for somatostatin, but negativity for carcinoembryonic antigen, calcitonin, calcitonin gene-related peptide, thyroglobulin, insulin, glucagon and pancreatic polypeptide. These immunohistochemical results confirmed that the tumors observed in multiple endocrine organs were indeed metastatic from the rectal carcinoid, rather than being a new combination of MEN syndrome. Some neuroendocrine tumors may develop widespread metastasis, sometimes creating problems with differentiation from multiple primary endocrine tumors. Immunohistochemistry may be of great help in setting this issue.

Carcinoid Tumor↗
PubMed1990

Cryopreservation of mouse spermatozoa in the presence of raffinose and glycerol.

When mouse epididymal spermatozoa were rapidly frozen in two steps (37 to -70 degrees C for solid CO2 and -70 to -196 degrees C for liquid nitrogen) as pellets, 18% raffinose provided the greatest protection to ICR mouse spermatozoa against cold-shock; sperm motility and fertilizing ability were 43% and 22.4%, respectively. A small proportion of spermatozoa frozen with 10% sucrose was motile but incapable of fertilizing ovulated oocytes. Glycerol and dimethylsulphoxide were less effective at any concentration examined. However, the fertilizing ability of frozen-thawed ICR spermatozoa was significantly improved (35.5%) by addition of glycerol (1.75% final concentration) to medium containing 18% raffinose. Spermatozoa from one outbred (ddY) and 5 inbred (C57BL/6N, C3H/HeN, DBA/2N, BALB/c and kk) strains of mice were successfully frozen in the presence of 18% raffinose and 1.75% glycerol, although the fertilization rates of frozen-thawed spermatozoa varied among strains (13% for C57BL/6N to 64% for DBA/2N). A small fraction of mouse eggs resulting from fertilization by frozen-thawed spermatozoa developed normally in vitro (37% in C57BL/6N to 71% in ICR) to the blastocyst stage and in vivo (19% for C57BL/6N spermatozoa and ddY oocytes) to Day 18 of gestation.

Animals↗
PubMed1990

[Stress distribution of supporting tissues under denture. Application of visco-elastic analysis in prosthetic field].

Viscoelastic finite element method was attempted to apply to the removable prosthodontic field. To examine the accuracy of this analysis, the results obtained from creep test of soft lining materials were compared with the calculated results by using this analysis. Stress relaxation in the supporting tissue under the upper complete denture was simulated by using viscoelastic analysis. The results were as follows; 1. The calculated results were in approximate agreement with experiment. 2. When the occlusal table of the denture was move 0.3 mm to the vertical direction, the calculated results indicated the soft tissue acted as a part of the stress relaxation in the supporting structures. 3. By using viscoelastic analysis, the time dependent deformation of the denture base and stress distributions in the supporting structures could be simulated.

Alveolar Process↗
PubMed1990

[A basic study on pressure distribution of supporting structures under complete denture. 1. Application of pressure dispersion analyzing system by using impedance grid sensor to measure the pressure of supporting structures under complete denture].

In order to measure the pressure distribution on supporting structures under complete denture, we used impedance grid pressure sensor and examined its accuracy and availability. The results were as follows: 1. The sensitivity of this sensor was high when the distance between electrodes was short. 2. This sensor showed large change in output voltage and high sensitivity in the case of soft elastic materials. 3. This sensor showed the high linearlity between output voltage and applied load. 4. This sensor showed hysteresis loop under cycle load. 5. Base line of this sensor that has the urethane rubber as elastic material was changed when the load was applied intermittently. We measured the pressure distribution over supporting bones under upper complete denture by using simulator of maxillary edentulous with this impedance grid pressure sensor. We could observe the pressure distribution and pressure region in detail and visually when the load was applied to the both occlusal tables evenly.

Alveolar Process↗
PubMed1989

Mouse Ly-31.1 is an alloantigenic determinant of alkaline phosphatase predominantly expressed in the kidney and bone.

The mouse lymphocyte surface alloantigen, Ly-31, defined by monoclonal antibody N1.10 (IgG2b,k) and controlled by a gene locus closely linked to the Akp-2 locus on chromosome 4, was biochemically investigated. By employing a quantitative immunoassay system, it was found that the Ly-31.1-specific antibody detected an allotypic determinant of mouse alkaline phosphatase. Ly-31.1, i.e., mouse alkaline phosphatase, was expressed predominantly in kidney and bone and was also detected in placenta, lung, and testis. Concerning tumor cell lines, they varied in the amount of antigen present, with both T and B lymphoid lineages selectively possessing the antigen. In normal lymphoid tissues, lesser amounts of antigen were detected. The binding of mouse alkaline phosphatase to Ly-31.1-specific monoclonal antibodies was specific in nature. The Ly-31.1 antigen was immunoprecipitated from the lysates of surface-radiolabeled YAC-1 moloney leukemia cells, and appeared as a single band of about 78,000 under both reduced and nonreduced conditions on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Furthermore, treatment of tumor cell lines with phosphatidylinositol-specific-phospholipase C resulted in the removal of Ly-31 antigen from the cell surface. These results suggest that a gene cluster containing the Ly-31 and Akp-2 loci which control the alkaline phosphatase is formed on mouse chromosome 4. The Ly-31 antigen is the first enzyme demonstrated to be a lymphocyte surface alloantigen.

Alkaline Phosphatase↗
PubMed1989

Effects of gammalinolenic acid on plasma lipoproteins and apolipoproteins.

Nineteen hypercholesterolemic patients (10 without and 9 with hypertriglyceridemia) were given evening primrose oil rich in gammalinolenic acid (GLA, 18: 3n - 6), in a placebo controlled cross-over design, over 16 weeks (8 + 8 weeks), with safflower oil as the placebo. During supplementation with evening primrose oil, dihomogammalinolenic acid (20: 3n - 6) increased in plasma lipids and red blood cells, and in subjects without hypertriglyceridemia there was a significant decrease in low density lipoprotein-cholesterol and plasma apolipoprotein B compared with the levels observed during safflower oil administration. Our results confirmed that evening primrose oil is effective in lowering low density lipoprotein in hypercholesterolemic patients.

Adult↗
PubMed1989

C cell carcinoma of the thyroid. Follicular variant.

A case of C cell carcinoma of the thyroid with an unusual follicular growth pattern of the cancerous C cells is described. The primary tumor consisted of a mixture of medullary and follicular features while the metastatic foci in the lymph nodes and liver displayed only a medullary arrangement. Histochemical study disclosed numerous argyrophilic cells in both the follicular and medullary parts. These cells were immunohistochemically positive for calcitonin, calcitonin gene-related peptide (CGRP) and other peptides as well as carcinoembryonic antigen (CEA), but negative for thyroglobulin. Radioimmunoassay done on the tissue extract revealed a high content of calcitonin. Electron microscopy showed small intracytoplasmic secretory granules and, in the follicular lining cells, formation of microvilli. A minor component consisting of glandular structures has been reported in medullary carcinoma of the thyroid, suggesting a potentiality for glandular differentiation of the C cells. In equivocal cases, immunohistochemical examination for calcitonin and thyroglobulin is essential for accurate diagnosis of thyroid carcinoma.

Adenocarcinoma↗