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Biomedical subjects

T Oda

Publications and source records attributed to T Oda.

At least 631 records · Page 35Linked to original sources
PubMed1985

Effects of nucleoside triphosphates and ferrous ions on bleomycin-induced unscheduled DNA synthesis.

Bleomycin-induced, unscheduled DNA synthesis (UDS) in Triton X-100-permeabilized mouse ascites sarcoma cells was enhanced 2- to 5-fold by addition of ribonucleoside triphosphates at 0.2-2.0 mM and 1.5- to 3-fold by addition of ferrous ions at 10 microM. Sensitivity to deferoxamine, a specific iron chelator, suggested that iron was essential to nucleotide-enhanced, bleomycin-induced UDS. Enhancement by nucleotides was not attributed to iron impurities in the nucleotide preparations, because ferrous ions did not substitute for nucleotides, but nucleotides further enhanced bleomycin-induced UDS which was maximally stimulated by the optimal concentration of ferrous ions. The effects of nucleotides and ferrous ions on bleomycin-induced UDS were thought to be due to increased bleomycin-induced DNA damage rather than enhanced DNA synthesis. The results suggest that pharmacological action of bleomycin is affected by the concentrations of nucleotides as well as ferrous ions.

Animals↗
PubMed1985

Spectrophotometric determination of oxalate in urine and plasma with oxalate oxidase.

In order to establish a standard procedure for the spectrophotometric determination of urinary and plasma oxalate with oxalate oxidase (Laker, M.F., et al. (1980) Clin. Chem. 26, 827-830; Sugiura, M., et al. (1980) Clin. Chim. Acta 105, 393-399) and to define the limitations of the method, the procedures and reactions involved in the assay have been examined. Among the chromogenic hydrogen donors for peroxidase tested, a combination of 3-methyl-2-benzothiazolinone hydrazone (MBTH) and sodium N-sulfopropylaniline (HALPS) was found to be best for the oxalate determination under the conditions used. Urine contained substance(s) which were inhibitory to the measurement of hydrogen peroxide by the peroxidase-catalyzed oxidative condensation of MBTH and HALPS, but they were largely removed by charcoal treatment at pH 5.6 without significant loss of oxalate. Deproteinization of plasma was carried out by ultrafiltration through a membrane cone (Centriflo CF-25) at neutral pH. The plasma oxalate ultrafiltrability under the conditions employed was calculated to be approximately 95%. A standard assay system for oxalate in these urine and plasma samples was then set up based on a series of studies on the reactions involved in the assay. In the case of normal plasma, however, the absorbance change was very small due to the low concentration of oxalate, and in addition, pretreatment of plasma with excess oxalate decarboxylase followed by the ultrafiltration and oxalate determination did not abolish completely the oxalate oxidase-dependent absorbance increase. It was concluded that the enzymic method was useful for the assay of urinary oxalate and in detecting elevated levels of plasma oxalate such as those in hemodialysis patients but was not sensitive enough to determine accurately the normal or decreased level of oxalate in plasma. The apparent concentration of oxalate in normal human plasma was measured in this work as 3.5 +/- 0.8 microM (mean +/- S.D., n = 8), and this result was interpreted to mean that the concentration of plasma oxalate was less than approximately 3.5 microM, as estimated by the present method.

Blood Proteins↗
PubMed1985

Clinical and endocrine studies on patients with amenorrhoea associated with weight loss.

Two hundred and forty-three patients with amenorrhoea associated with weight loss were studied. At the onset of amenorrhoea, regardless of percentage weight loss, basal levels of LH were low and LH responses to LHRH were impaired. However, both basal and stimulated levels of FSH were comparable to normal. With resumption of menstruation, the basal and stimulated levels of LH were found to rise to normal, while FSH responses continued to exceed normal. However, 16.6% of 66 unimproved cases had normal responses but remained amenorrhoeic. Furthermore, amenorrhoea persisted in 71% of 31 patients with complete recovery of body weight. No significant correlation was noted between percentage weight loss and responsiveness to LHRH, nor between recovery of body weight and resumption of menstruation. Return to normal weight is desirable for resumption of normal cyclic menstruation and hypothalamic-pituitary function, but is not always effective.

Adolescent↗
PubMed1985

HBV-associated ultrastructures in the chimpanzees' livers with experimental hepatitis B.

An electron-microscopic study was carried out using chimpanzees' livers infected with experimental hepatitis B for the elucidation of intracellular development of HBV-associated ultrastructures and extracellular release of HBV. Core particles were first detected in the nucleus of liver cells at around the time of the first seropositiveness for HBsAg, and then in the cytoplasm. Subsequently, their budding into endoplasmic reticular cisterna was seen together with other core particles in the surrounding cytoplasm. Dane-like particles were seen in the cisterna, and also extracellularly nearby a liver cell with a marked proliferation of microvilli at the onset of liver cell injury. Thereafter, core-like particles were seen within electrondense amorphous material at the site of the contact between liver cell and lymphocyte. The above sequence of features suggested us the assembly of core particles and surface envelope at the cisternal membrane of endoplasmic reticulum, and a reversed pinocytosis whereby Dane or HBV particles were released extracellularly. The filamentous structures within endoplasmic reticular cisternae, which were thought to be HBsAg, were never detected.

Animals↗
PubMed1985

Ultrastructural changes of the bile secretory apparatus and bile ductule in experimental hepatitis B with neither apparent biochemical nor light-microscopic cholestasis.

An ultrastructural study on the hepatic bile secretory apparatus and bile ductules was carried out using liver biopsy specimens of six chimpanzees with experimental hepatitis B. Although biochemical cholestasis was very mild or lacking and light-microscopic evidence of cholestasis was not evident, various ultrastructural changes which had been described in association with cholestasis were detected. The significance of these ultrastructural changes in relevance to cholestasis was difficult to determine, nevertheless electron-microscopic examination could possibly be the most sensitive means for the diagnosis of cholestasis. These ultrastructural changes appeared to be indifferent to the necrotizing process of liver cells in experimental hepatitis B.

Animals↗
PubMed1985

Ultrastructural studies on liver cell necrosis and lymphocytes in experimental hepatitis B.

Ultrastructural studies on liver cell necrosis and the interaction of lymphocyte and liver cell were carried out in experimental hepatitis B in chimpanzees. Two types of liver cell necrosis were identified. One was a lytic necrosis, and the other was a coagulation necrosis. Both types of liver cell necrosis were closely associated with the apposition of lymphocytes. The interaction (or close contact) of lymphocyte and non-necrotic liver cell infected with HBV was also detected. There were two distinct patterns of the contact. One was the direct contact, and the other was the contact with the intervention of electron-dense fuzzy material containing 20 to 22 mu spherical particles and 51 to 55 mu double-layered spherical particles. The ultrastructural characteristics of lymphocytes in each pattern of the contact were different. The results suggested that the pathogenesis of liver cell necrosis in hepatitis B was closely associated with the action of lymphocytes, and two modes of lymphocytic reaction were conceivable.

Animals↗
PubMed1985

Percutaneous transluminal coronary angioplasty for multiple lesions in a coronary artery--report of two cases.

Percutaneous transluminal coronary angioplasty (PTCA) was performed successfully in two patients with angina pectoris who had two separate significant stenotic lesions in a coronary artery. One patient had stenoses in segments 6 and 7 of the left anterior descending coronary artery. After PTCA, angina disappeared, an exercise ECG became negative and a 201Tl myocardial scintigram returned to normal. In the other patient, two separate stenotic lesions were found in segment 3 of the RCA. Angina and an exercise ECG improved after PTCA. These results suggest the validity of PTCA for multiple stenotic lesions in the same coronary artery.

Angioplasty, Balloon↗
PubMed1985

Difference in the homology of two nuclear nonhistone protein fractions as compared by polyacrylamide gel electrophoresis.

The extent of homology between two protein fractions was compared by simple electrophoretic analysis. Nuclear proteins of several rodent cells of different origins were fractionated into acid-soluble and acid-insoluble fractions. The two protein fractions were subjected to polyacrylamide gel electrophoresis in separate gel systems, and protein bands with identical mobilities were sought either in all possible combinational pairs of cell types or in all cell types. The paired and overall homology indices calculated from these data and chi-square testing of the results indicated that acid-soluble nuclear nonhistone proteins are more homologous than acid-insoluble nuclear proteins. Several factors which might have affected the results were discussed.

Animals↗
PubMed1985

Isozymes of human erythrocyte pyrimidine 5'-nucleotidase.

A scheme for the partial purification of human erythrocyte pyrimidine nucleotidase isozymes is presented. The characteristics of three of these were distinctively established. One isozyme, designated pyrimidine nucleotidase (PyrNase), is active for uridine monophosphate (UMP) and cytidine monophosphate (CMP), but not for thymidine monophosphate (dTMP). Two other isozymes, designated thymidine nucleotidase I (ThyNase I) and thymidine nucleotidase II (ThyNase II), were active for dTMP, but less so for UMP and CMP. Molecular weights of PyrNase, ThyNase I, and ThyNase II were estimated as 52,000, 52,000, and 48,000, respectively. Isoelectric points of these isozymes were 5.22, 4.90, and 4.68, respectively. Kinetic study revealed that the Km value for dTMP of ThyNase I was 3.83 mmol/L and of ThyNase II was 6.26 mmol/L.

5'-Nucleotidase↗
PubMed1985

Hypomethylation of c-myc and epidermal growth factor receptor genes in human hepatocellular carcinoma and fetal liver.

The methylation state of cellular oncogenes (c-oncs) and epidermal growth factor (EGF) receptor gene from human liver tissues was examined by means of restriction endonuclease analysis. c-myc and EGF receptor gene from hepatocellular carcinoma and fetal liver were substantially hypomethylated in comparison with those genes from normal liver, while the extents of methylation of c-mos and c-Ki-ras genes were the same among these tissues. It can be speculated that the specific hypomethylation of c-myc and EGF receptor genes may be associated with the development of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1985

Effect of coenzyme Q10 on stress-induced cardiac dysfunction in paediatric patients with mitral valve prolapse: a study by stress echocardiography.

Stress echocardiography (stress echo) by means of isometric handgrip has been proven to be useful for detection of latent cardiac dysfunction in patients with mitral valve prolapse (MVP). In MVP with symptoms (symptomatic MVP), handgrip (HG) stress usually induced an abnormal response, i.e. a decrease in the ejection fraction (EF) in accordance with other echo indices. If an effective treatment with coenzyme Q10 (CoQ) is performed, the response becomes normal (increase in EF) and symptoms disappear. Four hundred consecutive symptomatic MVP were divided into 6 groups according to the dose of CoQ, i.e., 0.6-0.9, 1.0-1.4, 1.5-1.9, 2.0-2.4, 2.5-2.9 and 3.0-3.4 mg/kg/day and followed up with repeated HG. There was a strong relationship between the dose and the time needed for normalization. In the 3.0-to-3.4 mg group, the majority of patients acquired a normal response within 1 week. When a single blind test between CoQ (N = 8) and ATP (adenosine triphosphate, N = 8) groups was conducted, the number of patients normalized within 8 weeks was 7 in the former and 0 in the latter. After reduction of the dose, 41 patients had relapses (re-abnormalizations) within 15 weeks (mean = 6.6). Continuous normalization for 4 months or longer after termination of CoQ occurred 7 to 43 months (mean = 18.5) after onset of symptoms, probably reflecting the self-limited natural course. Some patients (5.8% of patients followed up) showed polycyclic long courses like those of congestive cardiomyopathy and needed long-term CoQ treatment. CoQ was definitely effective for symptomatic MVP and improved stress-induced cardiac dysfunction if the appropriate dose was given. No side-effect was seen.

Adenosine Triphosphate↗
PubMed1985

Intrasplenic grafting of 7,12-dimethylbenz (a) anthracene-treated ovarian piece.

Immediately after a direct application of a chemical carcinogen, 7,12-dimethylbenz (a) anthracene (DMBA), the ovarian piece containing DMBA was implanted into the spleen of Wistar strain rats with or without gonadectomy. Six months after these treatments, an intrasplenic neoplasm was found in four of nine gonadectomized rats and in two of ten rats without castration. The volume of the induced tumor in the former group was 1.85 cm3 in average and that in the latter was 0.25 cm3. Histologic examination indicated that all of the induced tumors were not in the sex cord-stromal category, but adenocarcinomas. No morphological differences between the tumors in the castrated group and those in the noncastrated group could be detected by light microscopy. From the difference in the volume and the incidence of the induced tumors in the two groups, it appears that the hyperstimulation of the pituitary gonadotropins in the castrated rats promoted the tumorigenic process of the induced 'epithelial' ovarian cancer caused by the DMBA application to the grafted ovarian pieces.

9,10-Dimethyl-1,2-benzanthracene↗