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Biomedical subjects

T Tsuda

Publications and source records attributed to T Tsuda.

At least 289 records · Page 16Linked to original sources
PubMed1994

Radical scavenger effect of Boschniakia rossica.

To elucidate the mechanism of the invigorating and antisenile action of the dried herb of Boschniakia rossica (Boschniakiae Herba), the free radical scavenging activity of its 50% ethanol extract (BR) was examined using an electron spin resonance spectrometer. The scavenging activity of plasma from Fisher-334 rats with continuous administration of BR was also examined. The concentrations showing 50% inhibition of the free radical of BR on the 1,1-diphenyl-2-picrylhydrazil (DPPH) radical, superoxide radical and hydroxyl radical were 0.003%, 0.06% and 9.67%, respectively. Plasma from the rats with BR administered clearly showed higher free radical scavenging activity compared with that of normal control rats. These findings suggest that Boschniakia rossica has strong free radical scavenging activity and consequently it has inhibitory effects on the disorders caused by free radical production in living tissue.

Administration, Oral↗
PubMed1994

Analysis of the functional effects of a mutation in SOD1 associated with familial amyotrophic lateral sclerosis.

Mutations in the Cu, Zn superoxide dismutase (SOD1) gene have been reported in some pedigrees with Familial Amyotrophic Lateral Sclerosis (FALS). We have investigated the functional and structural effects of a Gly-->Ser mutation at codon 41 of SOD1 in a pedigree with FALS and the topography of SOD1 expression in the mammalian CNS. These analyses show that the 41Gly-->Ser mutation causes a 27% reduction in Cu, Zn SOD activity. SOD1 is transcribed at high levels in rat motoneurons and four other types of neurons homologous to upper motoneurons that degenerate in human ALS. However, SOD1 is transcribed at lower levels in other types of neurons, such as cerebellar Purkinje cells, which are not usually involved significantly in human ALS. On the other hand, immunocytochemical studies indicate that most types of rat neurons contain similar levels of Cu, Zn SOD immunoreactive protein. Nevertheless, these results suggest that the essential feature causing this subtype of ALS is either a reduction in Cu, Zn SOD activity in cell types that presumably critically require Cu, Zn SOD for protection against oxidative damage or the fact that the mutation in SOD1 associated with FALS results in a novel gain of function that is particularly deleterious to those cell types expressing SOD1 at high levels.

Amino Acid Sequence↗
PubMed1994

Work environment of plants manufacturing asbestos-containing products in Japan.

In 1985, a comprehensive study of asbestos-containing product plants (A/C, friction, textile) was performed. The data presented were based not on personal but on area sampling. A conversion equation from area sampling data to personal exposure values was developed. Exposure concentrations were 0.07-0.66 f ml-1. In workplaces which belonged to member companies of the Japan Asbestos Association, the percentage of workplaces whose exposure concentrations was less than 0.3 f ml-1 was 70% in 1985 (N = 510), but 98% in 1992 (N = 430). Concentrations in a new, well-controlled A/C plant were less than 0.1 f ml-1.

Asbestos↗
PubMed1994

An extra phosphorylation of Na+,K(+)-ATPase by paranitrophenylphosphate (pNPP): evidence for the oligomeric nature of the enzyme.

Paranitrophenylphosphate (pNPP) induced fluorescence changes in fluorescence isothiocyanate (FITC)-labeled Na+,K(+)-ATPase preparations. The extents of changes were similar to those induced by acetylphosphate (AcP) accompanying accumulation of a K(+)-sensitive phosphoenzyme (E2P) and an ouabain bound phosphoenzyme in the presence of Mg2+ and 16 mM Na+. Phosphoenzymes formed from [32P]pNPP were shown to turn over. The ratio of the maximum amount of the phosphoenzyme formed from pNPP to that of the phosphoenzyme formed from ATP and that of the ouabain-enzyme complex under steady-state conditions was shown to be close to 1:0.5:1. Such extra phosphorylation has hitherto only been observed in a transient state with the additions of high concentrations of ATP [Peluffo, R.D., Garrahan, P.J., and Rega, A. (1992) J. Biol. Chem. 267, 6596-6601]. Our data are compatible with the simultaneous presence of high and low affinity ATP-binding sites in Na+,K(+)-ATPase [Hamer, E. and Schoner, W. (1993) Eur. J. Biochem. 213, 743-748]. The maximum amount of paranitrophenol-sensitive fraction to synthesize [32P]pNPP in fully accumulated ADP-sensitive phosphoenzyme (E1P) from [32P]ATP was around 1/4 of the amount of ouabain-enzyme complex. These data and others indicate that a much higher degree of oligomerization, rather than (alpha beta)2, may be the functional unit of the enzyme in the membranes.

Adenosine Triphosphate↗
PubMed1994

Resistance to pseudorabies virus with enhanced interferon production and natural killer cell activity in mice treated with serum thymic factor.

Susceptibility to pseudorabies virus (PRV) infection in mice, which were continuously depleted of natural killer (NK) cell activity by injection of anti-asialo GM1, was examined. Effects of serum thymic factor (FTS) on susceptibility of mice to PRV were also investigated. In mice with depleted NK cell activity, the mortality of PRV-infected mice was markedly high, whereas that of FTS-pretreated mice was significantly lower than the controls. Reduced susceptibility to PRV was demonstrated in mice treated with anti-asialo GM1 antisera before the PRV infection. Such a reduced susceptibility was not observed in mice inoculated with the antisera on day 1 post-infection (PI). To analyze the FTS-induced resistance to PRV infection, NK cell activity, macrophage activity, and interferon (IFN) productions were studied. Interferon production and NK cell activity were enhanced in the FTS-pretreated mice, suggesting that interferon may play an important role in this FTS-induced resistance to PRV infection.

Amino Acid Sequence↗
PubMed1994

A case of malignant hemangiopericytoma: an immunohistochemical and ultrastructural study.

We report one case of malignant hemangiopericytoma which started with a tumor in the lower jaw and multiple nodules in the lung. The tumor quickly metastasized to the brain and chemotherapy was not at all effective. Hemangiopericytoma is generally diagnosed by its histological characteristics. Recently, however, electron microscopy and immunohistochemical methods have been used for its diagnosis. In our case, electron micrograph showed the growth of hemangiopericytoma cells around immature endothelial cells. In addition, the tumor cells reacted positively only with anti-vimentin antibodies, and the endothelial cells in the tumor tissue were positive for antifactor VIII antibodies. The observed features were consistent with the characteristics of hemangiopericytoma.

Antibodies, Monoclonal↗
PubMed1994

Expression of nitric oxide synthase by cytokines in vascular smooth muscle cells.

In cultured vascular smooth muscle cells, the baseline mRNA and protein levels of an inducible type of nitric oxide synthase were barely detectable. Interferon gamma, tumor necrosis factor-alpha, and interleukin-1 beta each markedly increased mRNA and protein levels of this enzyme in parallel with the production of nitrite, a stable oxidative metabolite of nitric oxide. Actinomycin D abolished the cytokine-induced increases in mRNA levels and nitrite production. Cycloheximide, which abolished the cytokine-induced increase in nitrite production, had no effect on the interferon-gamma-induced increase in mRNA levels but partially inhibited that induced by interleukin-1 beta and markedly inhibited that induced by tumor necrosis factor-alpha. Transforming growth factor-beta 1, which inhibited the interferon gamma-, interleukin-1 beta-, and tumor necrosis factor-alpha-induced nitrite production, did not affect the increases in mRNA levels caused by these cytokines. Transforming growth factor-beta 1, however, significantly inhibited the increase in protein levels caused by these cytokines. These findings suggest that interferon gamma directly induces the expression of the inducible nitric oxide synthase gene, whereas tumor necrosis factor-alpha and interleukin-1 beta induce it, at least in part, via the induction of intermediary protein(s), and that transforming growth factor-beta 1 inhibits cytokine-induced nitric oxide production by blocking the posttranscriptional synthesis of inducible nitric oxide synthase.

Amino Acid Oxidoreductases↗
PubMed1994

SOD1 missense mutation in an Italian family with ALS.

We have discovered a new Italian pedigree with autosomal-dominant ALS. The pedigree, at present, comprises 75 members distributed in five generations. ALS was diagnosed in eight patients. The mean +/- SD age of onset of the disease was 46.8 +/- 13.5 years, with a range of 29 to 63 years. The mean +/- SD duration of the disease was 11.6 +/- 1.7 months. Molecular genetic studies showed a missense mutation (Gly-->Ser, codon 41) in exon 2 of the Cu/Zn superoxide dismutase gene (SOD1) on chromosome 21 in the available affected member and in 45% of the at-risk subjects of the pedigree. This study confirms the presence of SOD1 point mutations in families with autosomal-dominant ALS and suggests that additional genetic or environmental factors may be involved in the full expression of the disease.

Adult↗
PubMed1994

[An epidemiologic research design using the Annual of the Pathological Autopsy Cases in Japan].

Epidemiologic research designs using the Annual of the Pathological Autopsy Cases in Japan (APAC hereinafter) are discussed in this paper. The APAC data base has been recommended for use in epidemiologic research. However, it has not often been utilized for such research, even though it covers all pathological autopsy cases in Japan, perhaps because of different sampling proportions of each disease and because of the dead control series in APAC. First, we present epidemiologic measures in using the APAC. We show that the data base can be treated as a case-control design and that the magnitude of the exposure effect should be estimated by an odds ratio. Next, selection bias and information bias in using the APAC are discussed. The independence of the control series from the exposure is important in the determination of the control disease. Because this design is based on internal comparison, non-differential misclassification should be stressed more than differential misclassification.

Autopsy↗
PubMed1994

Isolation and serological characterization of porcine reproductive and respiratory syndrome (PRRS) viruses from pigs with reproductive and respiratory disorders in Japan.

Three porcine reproductive and respiratory syndrome viruses (PRRSVs) were successfully isolated from stillborn piglets and fattening pigs derived from different herds affected either with an epizootic reproductive failure or a severe chronic respiratory distress in Japan. The isolates were reacted with antisera against both European (Lelystad virus) and American (strain 46448) PRRSVs in indirect immunofluorescence (IIF). However, cross immunoperoxidase monolayer assay revealed the close serological relationships between the Japanese isolates and American PRRSV, but not between the Japanese isolates and the European PRRSV. The data of preliminary serological survey with IIF technique showed a high frequency of antibody positive pigs against both Japanese isolate and the American PRRSV, whereas a low frequency of antibody positive pigs against the European PRRSV, on herds which have had clinical episodes of PRRS-like diseases. These results indicate that PRRSVs are prevalent in Japan, and suggest that the antigenicities of the prevalent PRRSVs are more closely related to those of the American than the European PRRSVs.

Animals↗
PubMed1994

Superior vena cava syndrome caused by a right apical tense bulla.

Superior vena cava (SVC) syndrome is caused by several diseases, although to our knowledge, a bullous lesion has not been reported previously. In the present case, severe pleural adhesion prevented the expanding bulla from stretching the visceral pleura and from compressing the residual lung, subsequently causing compression of the SVC and thus SVC syndrome.

Female↗
PubMed1994

Effect of digoxin on exercise performance in mildly symptomatic patients with idiopathic dilated cardiomyopathy and sinus rhythm.

The purpose of this investigation was to evaluate the effect of digoxin on aerobic performance in mildly symptomatic patients with congestive heart failure and sinus rhythm. Ten patients (8 men and 2 women) with idiopathic dilated cardiomyopathy (ejection fraction 17 to 33%, mean 27 +/- 4%) who were stable and mildly symptomatic with maintenance digoxin and diuretic therapy were studied. All patients underwent maximal symptom-limited ergometer exercise with analysis of respiratory gases during maintenance digoxin therapy, 4 weeks after digoxin withdrawal, and 4 weeks after digoxin readministration. Exercise capacity was assessed by peak oxygen uptake and anaerobic threshold. Serum digoxin concentration was 1.0 to 1.8 (mean 1.3 +/- 0.2) ng/ml during digoxin therapy, and less than the detectable level after digoxin withdrawal. No patients showed clinical deterioration after digoxin withdrawal. Peak oxygen uptake after digoxin withdrawal (23.7 +/- 3.0 ml/kg/min) did not differ significantly from that during maintenance digoxin therapy (23.8 +/- 2.5 ml/kg/min) or after digoxin readministration (24.1 +/- 2.9 ml/kg/min). The anaerobic threshold after digoxin withdrawal (14.9 +/- 2.5 ml/kg/min) did not differ significantly from that during maintenance digoxin therapy (15.0 +/- 2.1 ml/kg/min) or after digoxin readministration (14.9 +/- 2.2 ml/kg/min). No differences in heart rate and diastolic blood pressure were observed during exercise, but systolic blood pressure during exercise was significantly higher with digoxin therapy (p < 0.05). These results suggest that digoxin has no effect on aerobic performance in mildly symptomatic patients with idiopathic dilated cardiomyopathy and sinus rhythm.

Adult↗
PubMed1994

[201Tl scintigraphic evaluation of tumor mass and viability of bone and soft-tissue tumors].

To characterize 201Tl uptake in patients with bone and soft-tissue tumor, we studied 49 patients with surgically proven tumors and one patient with a tumor diagnosed arteriographically. In 37 of our 50 patients, the tumor was evaluated with 201Tl and arteriography. Moreover, in 14 of patients with pre-operative chemotherapy, pathologic changes were graded on the basis of percent tumor necrosis as defined histologically. The percent tumor necrosis histologically was compared with changes in the scintigraphic and conventional angiographic studies. Radiologic comparisons demonstrated a high degree of correlation with images of 201Tl and both arterial and blood pool phase of 99mTc-HMDP. Ninety-six percent of 28 malignant tumors had positive 201Tl uptake. None of the patients showed any thallium accumulation in the soft tissues or skeleton adjacent to the lesion. Activity of 201Tl was mainly dependent upon a tumor blood flow and a vascular density. In of 14 cases with the preoperative chemotherapeutic treatment, 201Tl scintigraphic changes showed concordance with % tumor necrosis. Thallium-201 was superior to 99mTc-HMDP in predicting tumor response to chemotherapy. Interestingly, delayed images of 99mTc-HMDP of 5 responders with > 90% tumor necrosis showed decreased uptake in the adjacent bone to the tumor mass lesions. It seems to be quite all right to consider that a major determinant of 201Tl uptake is intratumoral angiogenecity, which is closely connected with tumor viability. Therefore, 201Tl is a sensitive radiopharmaceutical for detection of vascular rich bone and soft-tissue tumors, and appears to be a simple and an accurate test for evaluating the response to specific therapeutic regimens of malignant bone and soft-tissue tumors.

Adolescent↗
PubMed1994

Expression of antral gastrin and somatostatin mRNA in Helicobacter pylori-infected subjects.

OBJECTIVES: We investigated the gene expression of antral gastrin and somatostatin in Helicobacter pylori-infected subjects. Twelve asymptomatic men with normal endoscopic findings participated in this study, four of whom were infected with H. pylori. METHODS: Biopsy specimens of the gastric mucosa were obtained after subjects had fasted overnight. Serum gastrin levels, antral gastrin and somatostatin content, and antral G- and D-cell densities also were measured. RESULTS: Fasting serum gastrin levels were significantly higher in H. pylori-positive subjects than in H. pylori-negative subjects. There were no differences between groups in antral gastrin content, G-cell density, or gastrin mRNA levels. Antral somatostatin content, D-cell density, somatostatin mRNA levels, and the somatostatin mRNA:D-cell density ratio were significantly decreased in H. pylori-positive subjects. CONCLUSIONS: Our results suggest that in addition to reduced antral D-cell density, a suppression of somatostatin synthesis in D-cells may have contributed to the decrease in antral somatostatin in H. pylori-infected subjects.

Adult↗
PubMed1994

[Evaluation of physicians' decision making processes in primary care medicine].

To investigate how primary care physicians select appropriate diagnostic tests in their clinical practice, we analyzed the physician's decision making processes by means of written case simulations. We allocated the physicians who participated in this study to three groups; nine residents and ten attending physicians from the Department of Primary Care Medicine, and nine specialists from the Department of Medicine in our hospital. After they read a history and findings in each presented case, the physicians were requested (1) to make diagnostic hypotheses and predict probability of each hypothesis, (2) to select diagnostic tests and their purpose, and (3) to estimate contribution of the tests to the diagnosis. The results revealed that the attending physicians tended to order the diagnostic tests more strictly based on their hypotheses than the residents and specialists did. The attending physicians selected diagnostic tests from specific varieties rather than from "Essential Laboratory Tests" when they were confident in their hypotheses. On the other hand, they selected the tests mainly from "Essential laboratory Tests" when they were uncertain of diagnosis or needed to exclude serious diseases. They regarded the contribution of tests to the diagnosis as high when specific diagnostic tests were available for the presumptive diagnosis, or severe conditions were expected. These findings suggest that, in the setting of primary care practice, the application of laboratory tests depends on the severity of presenting conditions and pre-test certainty of the diagnostic hypothesis. Therefore, it may not be always appropriate to apply "Essential Laboratory Tests" uniformly to every patient irrespective of his/her condition.

Adult↗
PubMed1994

[The risk factors of lymph node metastasis in submucosal invasive gastric carcinoma--assessment of the indication for endoscopic treatment].

Recent advances in endoscopic diagnosis and treatments have increased the number of early gastric carcinomas being treated by endoscopic resection. However, the appropriate criteria for endoscopic resection of gastric carcinomas with submucosal invasion are not completely established. During the past 12 years from 1980 to 1992, 116 lesions in 116 patients were treated by surgical operation for differentiated type submucosal invasive gastric carcinoma. In this study, the risk factors of lymph node metastasis were investigated clinicopathologically. As the result, 1) Heterogeneity of submucosal invasive tumor margin was demonstrated in 19 (16%) of the 116 lesions of which predominant histology was differentiated adenocarcinoma. 2) Lymph node metastasis was demonstrated in 16 (16%) of the 97 lesions of which histology was differentiated type. 3) Significant risk factors of lymph node metastasis was demonstrated in submucosal massive invasion (sm3), papillary adenocarcinoma, INF gamma, lymph vessel involvement (ly(+)), and existence of ulcer (ul(+)). 4) Sm3 and papillary adenocarcinoma (pap) had a higher malignant potential than ly(+), INF gamma, and ul(+) by multivariate analysis using the logistic regression. 5) All lesions with both well differentiated adenocarcinoma (tub1) and sm minimal invasion (sm1) had no lymph node metastasis. These results suggested that the lesions with both well differentiated adenocarcinoma tub1 and sm1, which have no other risk factors such as ly(+), INF gamma, and ul(+), may be considered as the appropriate indication for endoscopic treatment of gastric submucosal carcinoma.

Adenocarcinoma, Papillary↗