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Biomedical subjects

I Tanaka

Publications and source records attributed to I Tanaka.

At least 397 records · Page 22Linked to original sources
PubMed1989

Structural features of isolated generative cells and their protoplasts from pollen of some liliaceous plants.

Large quantities of intact generative cells and their protoplasts were isolated from pollen protoplasts of four liliaceous plants, and their structural features were investigated. The generative cells, liberated from the vegetative cell cytoplasm of the pollen protoplasts, were initially spindle-shaped with two long, oppositely oriented extensions, and were surrounded by two cell membranes, one on each side of a wall of uniform thickness. The generative nuclei, stained with 4',6-diamidino-2-phenylindole (DAPI), showed ellipsoidal and highly condensed chromatin, whereas the generative cell cytoplasm, whose quantity was widely different from species to species, showed no fluorescence, suggesting the absence of plastid and mitochondrial DNA, although many mitochondria were present. The isolated generative cells, which were spindle-shaped at first, became spherical in shape in vitro. Immunocytochemistry and transmission electron microscopy revealed that this change was associated with the depolymerization of an axial array of microtubules present in generative cells in situ. These results are discussed in relation to the function of the generative cell within the bicellular pollen of angiosperms.

Cell Separation↗
PubMed1989

A protein structural motif that bends DNA.

The prokaryotic protein HU, integration host factor (IHF) from Escherichia coli, and transcription factor 1 (TF1) from bacteriophage SPO1 are closely related molecules. Biochemical results suggest that the role of these proteins is to bind and bend DNA. From the high-resolution structure of HU, we propose a model for this interaction with DNA. Crucial amino acid differences between the proteins can be rationalized in terms of their different specific functions.

Bacillus subtilis↗
PubMed1989

Discovery of atrial natriuretic factor in the brain: its characterization and cardiovascular implication.

1. We have devised a radioimmunoassay for atrial natriueretic factor (ANF). Its application to rat brain extract led to the discovery of ANF in the brain. In addition to the hypothalamus and the pontine medullary region, it was widely distributed. 2. ANF in the brain is stored in a low molecular weight form, in contrast to pro-ANF in the atria. Thus, the processing of pro-ANF in the bran neuronal cells is different from that in the atria. 3. ANF was found in the anterior and posterior lobes of the pituitary, the peripheral ganglia, adrenergic neurons, and the adrenal medulla. 4. Brain ANF suppressed stimulated dipsogenesis, basal and stimulated vasopressin release, and angiotensin II-stimulated pressor effects. 5. ANF in the peripheral neuronal system inhibits catecholamine synthesis and release. Thus, central ANF functions to reduce the peripheral fluid volume and vascular tone in concert with the peripheral ANF.

Animals↗
PubMed1989

First trimester prenatal diagnosis of haemophilia A using factor VIII gene probe.

Accurate first-trimester prenatal diagnosis was achieved in a Japanese haemophilia A family by the use of a restriction fragment length polymorphism (RFLP) located within the F.VIII gene. Since the pregnant woman's heterozygosity for BclI polymorphism in F.VIII/intron 18 (F8A) probe was informative, chorionic villus sampling (CVS) was performed at 9 weeks of gestation. Restriction analysis showed that the fetus was heterozygous for the BclI site and had received a normal paternal X chromosome (0.9 kb) and a normal maternal X (1.2 kb). Therefore, we concluded that the fetus was a non-carrier female. Pregnancy went to term and woman gave birth to an apparently healthy female. At one week after birth a coagulation study confirmed that the newborn infant is not a carrier. The first-trimester prenatal diagnosis of haemophilia A is possible by CVS due to a RFLP in the F.VIII gene.

Blotting, Southern↗
PubMed1989

Lipid peroxidation and the metabolism of glutathione in rat liver and brain following ethylene oxide inhalation.

The effects of repeated exposure to ethylene oxide on lipid peroxidation and glutathione metabolism in both rat liver and brain were examined. Increased levels of malondialdehyde (MDA) in the liver were observed after 6 and 13 weeks of exposure to ethylene oxide. The increased level of MDA observed in the hepatic homogenates of the treated rats reflected that of the microsomal fraction. On the other hand, no change in the level of MDA was detected in the brain of rats either at a 6- or 13-week treatment. Glutathione reductase activity was found to decrease at 6 or 13 weeks in liver and brain of treated rats. Both reduced and oxidized forms of glutathione in homogenates of liver and brain obtained from treated rats were, however, similar to those of the control at 40 h after the last exposure in individual experiments. To elucidate the cause of lipid peroxidation, the time course of glutathione content after exposure with ethylene oxide were studied in more detail. Significant decreases in both GSH and GSSG content in these organs were detected shortly after exposure to ethylene oxide and their levels recovered gradually with time and reached the control values at 40 h in the liver, although the changes were less significant in the brain as compared with those in the liver. These results suggest that enhancement of lipid peroxidation in the microsomal fraction of the liver after repeated exposure to ethylene oxide may possibly arise from repeated depletions of glutathione to certain critical levels and less removal of lipid peroxidation.

Administration, Inhalation↗
PubMed1989

Effect of atrial natriuretic peptide on the release of beta-endorphin from rat hypothalamo-neurohypophysial complex.

The aim of this study was to determine whether atrial natriuretic peptide (ANP) alters beta-endorphin (beta-END) secretion from rat intermediate pituitary and whether this effect is a direct action on the intermediate pituitary or an indirect one mediated by hypothalamic factor(s). We studied the release of beta-END from rat neuro-intermediate lobes of the pituitary (NIL) and from the hypothalamo-neurohypophysial complex (HNC), which consists of the hypothalamus, pituitary stalk, intermediate and posterior lobes of the pituitary, by means of an in vitro perifusion system. NIL and HNC were prepared from male Wistar rats and individually perifused for 30 min with perifusion medium followed by 20 min perifusion with medium containing alpha-rat ANP and/or dopamine (DA). Samples of perifusion medium were collected every 5 min and subjected to RIA for beta-END. The basal release of beta-END from NIL was 180% of that from HNC (p less than 0.01), which provides further support for the presence of hypothalamic factors that inhibit beta-END release from the intermediate pituitary. The perifusion of HNC with ANP at 10(-7) and 10(-6) M increased the beta-END concentration by 25 and 50%, respectively (p less than 0.01). In contrast, ANP (10(-8) to 10(-6) M) had no effect on beta-END release from NIL. The inhibitory effect of DA (10(6) M) on beta-END release from NIL and HNC (51% and 50% of the basal release, respectively, p less than 0.01) was confirmed. However, this inhibitory effect was not reversed by ANP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Effect of sodium valproate on the secretion of proopiomelanocortin derived peptides from cultured rat anterior pituitary cells.

We examined effects of sodium valproate, a gamma amino butyric acid (GABA)-transaminase inhibitor, on the secretion of immunoreactive (IR)-ACTH and IR-beta-endorphin/LPH from cultured rat anterior pituitary cells to determine whether sodium valproate has a direct action on the secretion of ACTH and its related peptides from the cultured rat anterior pituitary gland. During the 3 h incubation, the basal secretion of IR-ACTH and IR-beta-endorphin/LPH decreased to 50.8% and 58.3%, respectively, of the control concentration after adding 10(-7) M sodium valproate into the incubation media and to 67.7% and 69.3%, respectively, of the control levels with 10(-8) M sodium valproate. However, sodium valproate at a concentration of 10(-6) M or 10(-9) M did not affect the basal concentration of IR-ACTH and IR-beta-endorphin/LPH. Sodium valproate at a concentration of 10(-7) M significantly attenuated the stimulated release of IR-ACTH and IR-beta-endorphin/LPH by 10(-9) or 10(-10) M of ovine corticotrophin releasing factor. These results indicate that sodium valproate could directly effect rat anterior pituitary cells to suppress both basal and stimulated release of proopiomelanocortin derived peptides and this supports the hypothesis that sodium valproate has a direct effect at the pituitary corticotroph in reducing plasma ACTH.

Adrenocorticotropic Hormone↗
PubMed1989

[Properties of factor VIII/von Willebrand factor in two highly-purified factor VIII concentrates, Hemofil M and Monoclate, using monoclonal antibodies].

Properties of F. VIII/vWF in highly-purified factor VIII concentrates were examined using monoclonal antibodies. The F. VIII: C levels obtained with the chromogenic assay agreed with those obtained with the one-stage clotting method. The ratio between F. VIII: Ag and F. VII: C in Hemofil M and Monoclate was 1.09 and 1.34, respectively. The F. VIII: Ag levels assayed by monoclonal ELISAs were the same as those assayed by polyclonal ELISA, except that those assayed by C 5-ELISA tended to be higher. The ratio between F. VIII: Ag and vWF: Ag in Hemofil M and Monoclate was 105 and 45, respectively. Both concentrates lacked the large multimers of vWF and showed the intensification of the satellite bands. SDS-PAGE patterns showed almost no contamination. Immunoblot analysis revealed that F. VIII in both concentrates could react with 6 kinds of monoclonal antibodies to F. VIII. These results suggest that the fundamental structure of F. VIII molecule for coagulant activity in both concentrates are preserved.

Antibodies, Monoclonal↗
PubMed1989

[Hemostatic changes before and after the onset of disseminated intravascular coagulation].

We performed a blood coagulation study during the course of disseminated intravascular coagulation (DIC) in 34 patients with hematological malignancies. Risk factors of DIC such as increasing tumor mass, anti-tumor therapy and severe infections were frequently observed at onset of DIC, and influenced the prognosis of DIC. Before the onset of DIC, the DIC score and FDP value were slightly elevated, and they were significantly increased after the onset of DIC. Before the onset of DIC, the level of fibrinogen was significantly increased but it was decreased after the onset of DIC. These hemostatic abnormalities continued for about 2 weeks. Patients with DIC showing prolonged APTT and PT had a poor prognosis. The abnormalities of PT, FDP, fibrinogen, DIC score, FDP-D-dimer and fibrinopeptide A were significantly greater in DIC than in Pre-DIC defined as the period one week before the onset of DIC. FDP-D-dimer was also higher in Pre-DIC patients than in those without DIC. Although protein S and C 4 b binding protein were not decreased in DIC or Pre-DIC, Protein C activity decreased during the course of DIC, suggesting that FDP-D-dimer and Protein C activity were useful for diagnosis of Pre-DIC and DIC.

Blood Coagulation↗
PubMed1989

[Four successfully operated cases of ball thrombus in the left atrium].

The authors report four cases of the left atrial ball thrombus associated with mitral stenosis. Three of four which had floating ball thrombus in the left atrium presented with syncopal attacks and systemic embolism. Echocardiography was the most effective method for preoperative diagnosis of ball thrombus in the left atrium and mitralstenosis. After having accurate diagnosis of ball thrombus in the left atrium by echocardiogram, all of cases were treated urgently with removal of the thrombus and mitral valve replacement or mitral commissurotomy. During operation, the head down position and slight right lateral position had been maintained to prevent the impaction of the ball thrombus into mitral valve orifice and the immediate cardiopulmonary bypass by ascending aortic, superior and inferior venous cannulation were placed through midsternal splitting incision. Because of high frequency of peripheral embolism and sudden death, left atrial ball thrombus should be recommended to be removed urgently.

Aged↗
PubMed1989

[A case of sarcoidosis beginning with extensive ground-glass pattern on chest X-ray, accompanied with high fever and eosinophilia].

A 62-year-old woman was admitted to our hospital with a chief complaint of dyspnea on effort. Her temperature was 38 approximately 39 degrees C. Eosinophilia was seen in peripheral blood and the chest roentgenogram showed bilateral extensive ground-glass pattern, accompanied by air bronchogram. The extensive shadow fitted the description of "unstable shadow." Transbronchial lung biopsy specimens demonstrated the formation of non-caseating epithelioid cell granulomas with severe alveolitis and exudative change in alveolar spaces. In bronchoalveolar lavage fluid (BALF), the total cell count was normal but the lymphocyte population was increased to 28%. Pathological findings were suggestive of either sarcoidosis or hypersensitivity pneumonitis. Prednisolone therapy was started. As a result, her symptoms rapidly disappeared and the chest roentgenogram showed remarkable improvement for a short period. However skin lesions on bilateral lower extremities appeared after approximately one month from discontinuation of prednisolone. Skin biopsy specimens showed non-caseating epithelioid cell granulomas leading to the final diagnosis of sarcoidosis. About one month after the appearance of the skin lesion, the chest roentgenogram findings deteriorated. At this time, the BALF eosinophil population surprisingly increased to 24.9%. Chest roentgenogram showed rapid improvement again by administration of prednisolone. This case was considered to be a unique case of sarcoidosis from the point of view of the chest roentgenogram pattern, eosinophilia, clinical course and presence of severe alveolitis with exudative change in alveolar spaces.

Alveolitis, Extrinsic Allergic↗
PubMed1988

[Effects of chronic inhalation of ethylene oxide on the rat testes].

The effects of chronic exposure of ethylene oxide on the testes were investigated. When rats were exposed to 500 ppm, three times a week for 13 weeks, the testes of the exposed group became remarkably atrophic and their DNA content decreased proportionally. However, plasma testosterone concentration did not significantly change. In the testes the activity of glutathione reductase decreased by 45% and glutathione-S-transferase increased by 64%, respectively. These results suggest that ethylene oxide causes a definite toxicity in the testes and the abnormality of glutathione metabolism plays an important role in its toxicity.

Administration, Inhalation↗
PubMed1988

Increasing incidence and changing histopathology of primary lung cancer in Japan. A review of 282 autopsied cases.

A total of 282 autopsied cases of primary carcinoma of the lung were reviewed from 1950 to 1983 to determine the incidence of histologic types, sex and age distribution, and to compare the trends between Japan and the United States. There were 75 cases in Group A (1950-1964), 89 in Group B (1965-1974) and 118 in Group C (1975-1983). The overall incidence, 282 cases per 8546 autopsies, was 3.3%; the male-to-female sex ratio was 2.4:1, and the mean age was 62 +/- 11 years. Increases in incidence in men, women, and the total from Group A to C were all statistically significant (P less than 0.05). A predominance of adenocarcinoma over squamous cell carcinoma in all cases was apparent in all the groups, but the data showed a trend toward a reduction in the proportion of adenocarcinoma and increases in the proportion of squamous cell carcinoma and small cell carcinoma. In contrast, an increasing incidence of adenocarcinoma was reported in the USA.

Age Factors↗