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Biomedical subjects

K Hirota

Publications and source records attributed to K Hirota.

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

Induction of cytochrome P-450c and P-450d by metyrapone in the primary culture of rat hepatocytes.

The effects of metyrapone on qualitative changes in cytochrome P-450-dependent drug metabolizing activities in primary cultures of rat hepatocytes were investigated. Metyrapone apparently increased benzo(a)pyrene hydroxylation and maintained both ethoxycoumarin-O-deethylation and propoxycoumarin-O-depropylation, whereas it had little effect on methoxycoumarin-O-demethylation. Furthermore, P-450d (high spin type of P-448) as well as P-450c (low spin type of P-448) were induced by metyrapone, while P-450b and P-450e were not. In conclusion, metyrapone act as a 3-methylcholanthrene-like inducer in the primary cultures of rat hepatocytes.

Animals↗
PubMed1989

[Investigation into the actual condition of patients with occlusal disharmony at the Pedodontic Clinic of Kyushu University. Cases of anterior cross-bite in the deciduous dentition].

The total number of subjects was 2754 children (1354 boys and 1402 girls), who visited the Pedodontic Clinic of Kyushu University during the 5 year period from April 1st 1981 to March 31st 1986. We investigated the actual conditions of patients who complained of occlusal disharmony and who were ascertained to be associated with occlusal disharmony. The results were as follows: 1. The percentage ratio of patients with chief complaints concerning occlusions was 14.5% and the percentage of patients with various type of complaints as well as the problem of occlusion was 8.1%. The ratio of the sex of the patients who complained of their occlusal disharmony was 43.0% for boys and 57.0% for girls. 2. The age distributions of the patients who had as the chief complaint occlusal disharmony were at the ages of 3 and 6 to 7 at the maximum. 3. The number of patients who were diagnosed with occlusal disharmony at the first examination was 28.5%. These included anterior cross-bite 32.5%, edge to edge bite 14.1%, cross-bite 13.0%, crowding 11.8% and et al. 4. The distribution of anterior cross-bites due to the developmental stage was divided into the deciduous dentition 59.9%, the mixed dentition 39.3% and the permanent dentition 0.8%. 5. The sex ratios of anterior cross-bites in the deciduous dentition were 45.6% for boys and 54.4% for girls. 6. The treatment of occlusal guidance for anterior cross-bite in the deciduous dentition started from ages 3 to 5. 7. The appliances used for the treatment of anterior cross-bite in the deciduous dentition were maxillary protraction 25.0%, the chin cap 20.0%, the FKO 17.5%, and the lingual arch with herical springs 15.0% and et al. 8. The status of the patients with the anterior cross-bite in the deciduous dentition as of August 1986 was that the 36.2% was under the observation, and 24.4% was under the treatment of occlusal guidance or under the observation after the treatment was done.

Child↗
PubMed1989

[A case of hepatocellular carcinoma with a duodenal invasion from metastatic lymph node].

A 64-year-old male, who had been diagnosed as having hepatocellular carcinoma, was admitted to hospital and underwent transcatheter arterial infusion therapy. CT and US examinations revealed a large tumor with air in its center. Barium meal examination of the duodenum showed a large filling defect with a central excavation. At endoscopic examination, a dark reddish tumor was seen protruding into the duodenal lumen. A biopsy specimen from this tumor revealed a hepatocellular carcinoma. The patient subsequently died of hepatic coma following gastrointestinal bleeding. An autopsy revealed that metastatic lymph nodes had infiltrated into the adjacent duodenum. Nine previous cases of duodenal metastasis from a hepatocellular carcinoma have been reported in the Japanese literature.

Biopsy↗
PubMed1989

[A case of hepatocellular carcinoma (HCC) with a huge tumor thrombus in the right atrium].

A case of HCC with a huge tumor thrombus in the right atrium is reported. CT and celiac angiography revealed HCC in the liver. Inferior vena cavography and cardiac blood pool scintigraphy demonstrated a large defect in the right atrium, and 67Ga-citrate scintigraphy showed a lesion of abnormal accumulation in the right atrium. With these findings, diagnosis of HCC with a tumor thrombus in the right atrium was made, and the clinical diagnosis was confirmed by autopsy.

Carcinoma, Hepatocellular↗
PubMed1989

8-Methyladenosine-substituted analogs of 2-5A: synthesis and properties.

Four 8-methyladenosine-substituted analogs of 2-5A were obtained by a synthesis which involved a modification of the lead ion-catalyzed ligation reaction. Substituent of an 8-methyladenosine residue at the third position (2'-terminal) of the oligonucleotides increased the stability to snake venom phosphodiesterase digestion.

Adenine Nucleotides↗
PubMed1989

[Malignant thymoma detected by thallium-201 myocardial scintigraphy].

We present two cases of malignant thymoma which showed a remarkable accumulation of thallium-201 chloride on myocardial scintigraphy. A 69 year-old man underwent stress 201Tl scintigraphy to evaluate myocardial ischemia and abnormal accumulation of thallium activity was observed in the anterior mediastinum by chance. It was more clearly visualized on delayed image. Moreover, abnormal uptake of 67Ga citrate was also observed in the same region. In another 68 year-old woman, there was high uptake on 201Tl scintigraphy, but no abnormal uptake using 67Ga. The diagnosis of malignant thymoma was confirmed by operation in each patient. These two cases had no abnormality in the mediastinum on the chest X-ray film and one of them had no uptake of 67Ga, 201Tl scintigraphy was more useful to detect malignant thymoma.

Aged↗
PubMed1989

[An anesthetic experience with a patient with ornithine transcarbamylase deficiency].

We report an anesthetic experience with ornithine transcarbamylase deficiency. The patient was 26 years of age who underwent open biopsy of the liver for a definitive diagnosis. OTC deficiency is an X-linked disorder of urea cycle. One of the anesthetic problems is how to control the blood ammonia level resulting in neurological damage which occurs following anesthesia and surgery. Recently it has been advocated that benzoate is effective to prevent hyperammonemia in patients with OTC deficiency. As patients with this disease are frequently complicated with hepatic dysfunction, anesthetics which may cause hepatic damage such as halothane should be avoided.

Adult↗
PubMed1988

Inhibition of phorbol ester-caused induction of ornithine decarboxylase and tumor promotion in mouse skin by staurosporine, a potent inhibitor of protein kinase C.

We found that staurosporine, a potent inhibitor of protein kinase C, inhibits induction of ornithine decarboxylase (ODC) and tumor promotion caused by 12-O-tetradecanoylphorbol-13-acetate (TPA) in CD-1 mouse skin. When applied 5 min either before or after treatment with TPA, 1 microgram of staurosporine cause about 56% inhibition of ODC-induction by 5 micrograms of TPA. However, staurosporine did not inhibit TPA-induced epidermal hyperplasia. In two-stage carcinogenesis, staurosporine at 1 microgram was applied 5 min before application of 5 micrograms of TPA to the initiated skin: number of tumors was suppressed by about 40% although the incidence was not affected. No tumors developed when staurosporine alone was applied to the initiated skin.

Alkaloids↗
PubMed1988

Possible involvement of lipoxygenase pathway of arachidonic acid in rat pituitary hormone release in vitro.

The roles of arachidonic acid (AA) and its lipoxygenase products in control of secretion of anterior pituitary hormones were studied in vitro using cultured cells. AA (10(-4)M) and 5-hydroxy-eicosatetraenoic acid (5HETE) (5 x 10(-6)M) significantly (p less than 0.05) stimulated the releases of LH, TSH, GH, PRL, ACTH and beta-endorphin (beta-E). Added leukotriene B4 (LTB4) (5 x 10(-6)M) also caused significant increases in the secretions of LH, GH, ACTH and beta-E. The other lipoxygenase metabolites tested, 12HETE, 15HETE, LTA4, LTC4 and LTD4, had no effect on the releases of anterior pituitary hormones. These results suggest that AA and 5-lipoxygenase metabolites may be involved in the control of the releases of anterior pituitary hormones.

Adrenocorticotropic Hormone↗
PubMed1988

Influence of exercise on plasma atrial natriuretic factor levels in patients with myocardial infarction.

The influence of dynamic exercise on plasma atrial natriuretic factor (ANF) levels was studied in a group of 10 patients with myocardial infarction (MI) and five patients with atypical chest pain (control group). Exercise protocol consisted of three fixed workloads (25, 50, and 75 watts) every 4 minutes with the use of a supine bicycle ergometer. Plasma ANF levels and hemodynamic indices were measured before, during, and 10 minutes after exercise. In the MI group, plasma ANF levels significantly increased at the 75-watt workload and significantly decreased at 10 minutes after exercise, whereas in the control group, the increase in plasma ANP levels after a 75-watt workload, compared with those at rest, was not significant. Significant correlations of pulmonary artery wedge pressure, right atrial pressure, mean arterial pressure, and heart rate to plasma ANF levels were observed at four points obtained before and during each stage of exercise in the MI group. Furthermore, a significant correlation between maximal creatine kinase levels and plasma ANF levels at a 75-watt workload and a significant inverse correlation between left ventricular ejection fraction and plasma ANF levels at a 75-watt workload were observed. These results suggest that the increase in the circulating ANF level during exercise in MI is associated with elevated atrial pressure resulting from left ventricular dysfunction and that measurement of ANF during exercise may be an indication of the severity of MI and associated left ventricular dysfunction.

Adult↗
PubMed1988

Second pregnancy with spontaneous ovulation following clomiphene- or gonadotropin-induced pregnancy.

For investigation of the rates of spontaneous pregnancy following termination of pregnancy induced by treatment with clomiphene or human menopausal gonadotropin-human chorionic gonadotropin (hMG-hCG) and of spontaneous abortion in the second pregnancy, 119 women (58 with an anovulatory cycle and 141 with amenorrhea) who desired another pregnancy were studied. The rate of spontaneous pregnancy following pregnancy induced by clomiphene was 46.6%, which was significantly (p less than 0.001) higher than that following pregnancy induced by hMG (14.9%). The mean (+/- SEM) period between the termination of the first induced-ovulation pregnancy and the second spontaneous pregnancy was 16.6 +/- 1.4 months. The spontaneous abortion rates in the second pregnancies after pregnancies induced by clomiphene and hMG were 7.5% and 9.8%, respectively, which were significantly (p less than 0.001, p less than 0.05) lower than those in the first pregnancy (25.7%, 33.0%). There was no difference between the spontaneous abortion rates following a first pregnancy which terminated in abortion and those following a pregnancy which ended in birth. These data suggest that a first pregnancy in anovulatory women may restore the ovulatory cycle and have a beneficial effect on the rates of spontaneous abortion in the second pregnancy.

Clomiphene↗
PubMed1988

Effects of halothane on membrane potentials and membrane ionic currents in single bullfrog atrial cells.

Halothane exerts negative inotropic and negative chronotropic actions on the isolated heart in experimental animals. In order to assess directly the actions of halothane in myocardium, we studied the effects of halothane on membrane potentials and transmembrane ionic currents in single isolated frog atrial cells obtained by the enzymatic dissociation method. The results show: (a) that the action potential is prolonged and its plateau phase and overshoot are depressed, but the resting potential remains unchanged; (b) that there is a significant inhibition of a time- and voltage-dependent outward K+ current and a slow inward Ca2+ current, with a slight decrease of a fast inward Na+ current following halothane (1.0-4.0%) application; and that halothane has no effect on another K+ current, time-independent current.

Animals↗
PubMed1988

Solubilization and characterization of the rat pituitary gonadotrophin-releasing hormone receptor.

Specific receptors for gonadotrophin-releasing hormone (GnRH) were extracted from the rat pituitary gland with several detergents and characterized by binding studies with the potent GnRH antagonist [Ac-D-pCl-Phe1.2, D-Trp3, D-Lys6, D-Ala10]-GnRH (GnRHant). The particulate GnRH receptors were most effectively solubilized with 5 mM 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulphonate (CHAPS), which extracted 63% of the original membrane binding activity when assayed with 125I-labelled GnRHant. The binding affinities of particulate and CHAPS-solubilized receptors analysed with 125I-labelled GnRHant were 1.5 +/- 0.4 x 10(9) M-1 and 1.2 +/- 0.2 x 10(9) M-1 respectively. Gel filtration of the CHAPS-solubilized receptor revealed a major peak of specific binding activity with Mr of about 700,000. A hormone-receptor complex of similar Mr was observed when CHAPS-solubilized receptors were labelled with photoreactive radioiodinated [D-Lys6]-des-Gly10-GnRH-N-ethyl-amide and then analysed by gel chromatography. However, when pituitary particles were photolabelled and solubilized in 2% Triton X-100 before analysis on Sephacryl S-300, the Mr of the receptor was approximately 250,000, similar to the value obtained by sucrose density gradient centrifugation of the CHAPS-solubilized receptor. After solubilization in sodium dodecyl sulphate (SDS) the photolabelled receptor was eluted from Sephacryl S-300 as a 60 kDa peak which on SDS-gel electrophoresis contained a 52 kDa component, corresponding to the major binding subunit extracted directly from photolabelled pituitary membranes. The difference in higher molecular weight forms observed under non-denaturing and denaturing conditions could reflect the need for additional membrane components to maintain the active conformation of the GnRH receptor site. Whereas the minimum Mr of the solubilized receptor is about 250,000 under non-denaturing conditions, analysis of the photolabelled GnRH-receptor complex by SDS chromatography and electrophoresis indicates that a binding subunit with Mr of 50,000-60,000 is present in the GnRH holoreceptor.

Affinity Labels↗