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Biomedical subjects

S Ohta

Publications and source records attributed to S Ohta.

At least 577 records · Page 32Linked to original sources

The vasculature and clinical application of the posterior tibial perforator-based flap.

Use of the posterior tibial flap pedicled on the posterior tibial vessels has been described by several authors, but with it there is the major disadvantage of an unavoidable transection of the posterior tibial artery. To overcome this disadvantage, we anatomically studied the perforators from the posterior tibial artery and used posterior tibial perforator-based flaps clinically. Based on our anatomic study of 25 cadaveric legs, the cutaneous perforators were considered to be distributed from the distal to the proximal sides of the lower leg through the medial border of the tibia, and they were classified into three types: septocutaneous perforators mainly located in the distal third of the leg, muscle perforators located in the proximal half, and periosteal perforators in the proximal third of the leg. The average size and number of perforators was 0.8 mm and 3.1 in one leg, respectively. A considerable number were located at sites from 70 to 140 mm superior to the medial malleolus. Based on our clinical cases repaired with flaps, we consider this flap to be useful as a free flap for the repair of defects of the extremities and as an island flap for reconstruction of defects on the anteromedial aspect of the lower leg. The territory of the flap is relatively wide, being 19 x 13 cm. The long saphenous vein can be used safely as the venous drainage system in the case of free-flap transfer.

Adult↗

Alpha-fetoprotein-producing immature mediastinal teratoma showing rapid and massive recurrent growth in an adult.

A case of immature mediastinal teratoma in a 43-year-old Japanese man is reported. The tumor, which was multicystic with solid zones and measured 12 x 6 x 8 cm, arose in the anterior mediastinum. The serum alpha-fetoprotein (AFP) level was elevated to 5,114 ng/ml before surgery. Histologically, the solid zones showed an admixture of irregular glands lined by columnar or cuboidal epithelium set in a spindle cell stroma, some foci of primitive neural tissue, and scattered small nests of hepatoid cells. Immunohistochemically, the hepatoid cells and epithelia lining some of the cysts showed a strongly positive reaction for AFP. Eight months after surgery, the patient died of respiratory failure caused by a rapidly growing massive recurrent tumor, which measured 40 x 24 x 13 cm, in the left thoracic cavity. However, the elevated serum AFP level had been decreasing during the course of the recurrence in response to chemotherapy. The recurrent tumor showed remarkable proliferation of loose mesenchymal tissue without primitive neural tissue. These findings suggest that immature mediastinal teratoma in adults is highly malignant, and that non-AFP-producing mesenchymal tissue played a critical role in forming the rapidly growing massive recurrent tumor in the present case.

Adult↗

Familial occurrence of growth hormone deficiency and primary hypothyroidism.

We examined endocrine function in three male siblings with growth hormone (GH) deficiency and primary hypothyroidism. Low GH responses to various provocative tests were revealed in all three. Exaggerated thyrotropin (TSH) responses to thyrotropin-releasing hormone increased basal TSH levels, and low free thyroxine levels were also found in all three. Additionally, a low testosterone response to human chorionic gonadotropin and low gonadotropin responses to luteinizing hormone-releasing hormone were noted in the youngest sibling. Skull X-ray films, computerized tomography and magnetic resonance imaging revealed no abnormalities of the pituitary gland or sella turcica. The GH gene was intact in all of the children and their parents. We diagnosed all siblings as having GH deficiency and primary hypothyroidism. This is the first report of familial occurrence of GH deficiency and primary hypothyroidism.

Adolescent↗

Contractile activity of porcine neuromedin U-25 and various neuromedin U-related peptide fragments on isolated chicken crop smooth muscle.

Contractile activity of porcine neuromedin U-25 (p-NMU-25) and various neuromedin U (NMU) peptide fragment amides was examined on chicken crop smooth muscle preparation. The relative activity (expressed as RA value) of p-NMU-25 to porcine neuromedin U-8 (p-NMU-8) was 5.51 +/- 0.09, and p-NMU-25 (15-25) was the most potent fragment with an RA value of 7.78 +/- 0.05. All C-terminal 11-peptide amides of rat, rabbit, and frog NMU peptides retained activity about three-fold higher than the corresponding C-terminal 8-peptide amides. The peptide segment Asn15-Arg-Arg17 of p-NMU-25, as well as the corresponding positions of various NMU peptides: Ser13-Gly-Gly15 of rat NMU and Ser15-Arg-Gly17 of rabbit and frog NMUs, appeared to be involved in the structural requirements for increased contractile activity in the assay system.

Amino Acid Sequence↗

Studies on chemical protectors against radiation. XXXV. Effects of radioprotective Chinese traditional medicines on radiation-induced lipid peroxidation in vivo and in vitro.

The fluctuation of lipid peroxidation (LP) in 9 tissues was investigated in mice for 7 d after whole-body X-irradiation with a lethal dose of bone marrow death. LP increased significantly in bone marrow, thymus, spleen and liver following irradiation, and slightly in brain and testis, but not in blood plasma, submaxillary gland or kidney. The effects of 7 radioprotective Chinese traditional medicines (CTMs) and cysteamine (MEA) on the radiation-induced LP in 4 tissues were studied by i.p. injection before or after irradiation and their LP content in tissues was measured 2 d after irradiation. Most CTMs showed significant inhibition of radiation-induced LP in bone marrow and liver, especially when injected prior to irradiation. Some CTMs also showed such inhibition in spleen. MEA only inhibited the increase of LP in liver when injected before irradiation, but enhanced the increase of LP in spleen. None of these radioprotectors including MEA was recognized to inhibit radiation-induced LP in thymus. The in vitro experiments were carried out using mouse liver microsomal suspensions (MS). The MS were prepared from normal (non-irradiated) mice. Each of the 8 radioprotectors was added to MS before or after irradiation and then post-irradiation-incubated at 37 degrees C. All markedly inhibited radiation-induced LP if added before irradiation, but were slightly less effective if added after.

Animals↗

[Synthesis of new antirusty disinfectants. I].

New quaternary ammonium salts [N-alkyl-N-2-hydroxyethyl-N,N-dimethylammonium ethyl phosphate (21, 22), isopropyl phosphate (23), n-butyl phosphate (24) and N-alkyl-N-2-hydroxy-3-phenoxypropyl-N,N-dimethylammonium ethyl phosphate (25, 26), isopropyl phosphate (27), n-butyl phosphate (28) and bis(N-alkyl-N-2-hydroxy-3-phenoxypropyl-N,N-dimethylammonium) malate (29), fumarate (30), succinate (31), adipate (32) and N-alkyl-N-2-hydroxy-3-phenoxypropyl-N,N-dimethylammonium tartrate (33)] were synthesized by alkylation of the corresponding trialkylammonium salts with various epoxy compounds. The new quaternary ammonium salts showed much greater bactericidal activities and antirusting effects than those of benzalkonium chloride. They had also good compatibilities since no precipitate was observed if the solution of any anionic surface active agents were added to the solution of these new quaternary ammonium salts. This property is the same as that of amphoteric surface active agents.

Bacteria↗

[Protective effects of the fractions extracted from the callus of Acer nikoense Maxim. on alpha-naphthylisothiocyanate induced liver injury].

It has been reported that the methanol extract from the bark of Acer nikoense MAXIM. (AN) and the fractions separated from this extract showed the protection for liver injuries induced by carbontetrachloride (CCl4) in rat. On the other hand, the evidence manifested that the fractions of the callus of young branches from AN were recognized to have protective effects on the CCl4-induced liver injuries in rat. In this study, the protective activities of the fractions extracted from the callus of AN were investigated on the alpha-naphthylisothiocyanate (ANIT)-induced liver injuries in rat. The protectively active principles on the ANIT-induced liver injuries were found in the ether soluble fraction. The components of the protective effect were purified by repeated silica gel chromatographies. One of the protective substances in this fraction was identified to be beta-sitosterol. The protective fractions on the ANIT-induced liver injuries showed the protective effects on ANIT-induced cholestasis, but did not show cholagogic effects.

1-Naphthylisothiocyanate↗

[Effects of various methanol extracts of crude drugs on experimental subacute and chronic hepatic injury].

The effects of 5 crude drugs (Myricae Cortex, Polygoni Avicularis Herba, Hyperici Erecti Herba, Forsythiae Fructus, Desmodii Herba) on subacute and chronic hepatic injuries induced by carbon tetrachloride (CCl4) or alpha-naphthylisothiocyanate (ANIT) were investigated in rats. All of these crude drugs suppressed significantly the increase of several biochemical parameters with CCl4-injection twice per week for 4 weeks. Polygoni Avicularis Herba and Desmodii Herba among 5 crude drugs also protected the subacute hepatic injury induced by ANIT-injection for 4 weeks. In addition, the therapeutic effect of Desmodii Herba on the chronic hepatic injury induced by CCl4-injection for 9 weeks was recognized. Desmodii Herba has protective effects on the acute and subacute hepatic injuries induced by CCl4 or ANIT and an improving effect on the chronic injury induced by CCl4. Though the increase of hydroxylproline content in the liver began 4 weeks after the CCl4 or ANIT treatment, every crude drug had no significant effect against the liver fibrosis in these study.

1-Naphthylisothiocyanate↗

[Protective effects of the bark of Myrica rubra Sieb. et Zucc. on experimental liver injuries].

The methanol extract from the bark of Myrica rubra SIEB. et ZUCC. showed protective effects on liver injuries induced by carbon tetrachloride (CCl4) and alpha-naphthylisothiocyanate (ANIT) in rats. In this study, the fractions and some compounds from the bark of M. rubra were investigated for the protection against CCl4 inducing liver injuries in rats. The active principles for the protection were recognized in two fractions (M-3 and M-5 Fr. 1) obtained from the methanol extract, and one of the active principles in the fraction (M-3) was found to be myricanol 5-O-beta-D-(6'-O-galloyl)-glucopyranoside. In addition, these fractions protecting liver injuries induced by CCl4 showed significant protective effects against cholestasis induced by ANIT.

Animals↗

[Preparation of water-soluble hydronaphthoquinone derivatives and its application to the determination of hydrogen peroxide in clinical chemistry].

Several 1-alkoxy-2,3-dichloro-4-hydroxynaphthalene derivatives were prepared. These compounds were oxidized by hydrogen peroxide in the presence of a peroxidase to give 2,3-dichloro-1,4-naphthoquinone, which then reacted with various alkyl benzoylacetates to develop blue coloration with absorption maximum at greater than 600 nm. The color development reaction can be applied to the determination of appropriate serum constituents such as cholesterol.

Color↗

Amphetamine-antagonistic property of 4-phenyltetrahydroisoquinoline: effect on noradrenaline release in spinal cord slices.

The amphetamine-related compounds methamphetamine, phenylethylamine and nomifensine increased the K(+)-evoked release of endogenous noradrenaline from rat spinal cord slices. 4-Phenyl-1,2,3,4-tetrahydroisoquinoline (4PTIQ), which alone did not affect the K(+)-evoked release of noradrenaline, inhibited the noradrenaline-releasing effects of methamphetamine, phenylethylamine and nomifensine. 4PTIQ revealed a weak noradrenaline-uptake inhibitory effect, and the effect was weaker than those of desipramine and nomifensine. These results showed that 4PTIQ is an antagonist against the amine-releasing effects of amphetamines.

Amphetamine↗

Effects of oxygen concentration on the metabolism of anisole homologues by rat liver microsomes.

1. The effects of oxygen concentration were studied on the metabolic pathways of anisole homologues (anisole, phenetole and isopropoxybenzene) catalysed by liver microsomes from phenobarbital-treated rats. 2. With increase of oxygen concentration, the rate of anisole o-hydroxylation reached a plateau at about 35 microM O2, while the rates of O-demethylation and aromatic p-hydroxylation were still increasing at 223 microM O2 (air). 3. The rates of all three metabolic reactions of phenetole reached plateau levels at about 80 microM O2. 4. The rates of all three metabolic reactions of iso-propoxybenzene were still increasing as 223 microM O2 (air). 5. The ratio of aromatic p-hydroxylation or O-dealkylation to aromatic o-hydroxylation decreased in anisole metabolism, and showed no uniform change in phenetole and isopropoxybenzene metabolism with decreasing oxygen concentration. 6. The ratio of aromatic p-hydroxylation to O-dealkylation was essentially constant over the range of oxygen concentration studied in anisole and phenetole metabolism, while in iso-propoxybenzene metabolism the ratio was different between higher and lower oxygen concentrations than 60 microM. 7. This series of compounds with increasing chain length did not show homologous changes in rates of product formation or O2 dependent of product formation.

Animals↗

[Mass-screening for ovarian cancer by means of transvaginal ultrasonography--study on size of ovary to select subjects requiring second screening].

Mass-screening for ovarian cancer by means of transvaginal ultrasonography has been performed in Aomori Prefecture since 1989. To select appropriate candidates to receive the second screening, the size of 44 normal ovaries removed by surgery and was measured studied on 10,692 ultrasonic pictures recorded on a VTR. The results were as follows: (1) All 44 ovaries were under 40mm. (2) In 3,806 (35.6%) of 10,692 women at the first screening, their ovaries were detected by ultrasonography. This detection rate was higher in young subjects and in the luteal and menstrual phases than in others. (3) Of these ovaries, 1,303 (34.2%) were under 19mm, 1,891 (49.7%) were 20-29mm and 614 (16.1%) were over 30mm in size. (4) The second screening was performed in 472 of the 614 women, and the size of the ovaries in 83 (17.6%) of them was under 29mm. (5) The frequency of ovarian size exceeding 40mm at the second screening, was 12.5% of the 30-39mm diameter group and 48.0% of the 40-49mm group at the first screening. There was no malignant tumor in the former, but there were one pre-malignant and one malignant tumor in the latter. These results indicate that the second screening should be performed for women having ovaries over 40mm in size.

Adult↗

Retinoblastoma in dizygotic twins born as extremely low birth weight infants.

A case of bilateral retinoblastoma affecting both of a pair of dizygotic twins was reported. To our knowledge, there has been only one previous report of dizygotic twins, both affected, with this disease. The present twins had no family history of retinoblastoma. They were born prematurely as extremely low birth weight infants after 26 weeks and 4 days of gestation, and 3 of the 4 tumors were detected at 33 weeks after conception. Using LINAC external radiation therapy followed by xenon photocoagulation when necessary, the tumors were successfully treated. These cases show that retinoblastoma can develop in the pre-term period, indicating that the second mutation involved in tumorigenesis can occur in the fetus.

Diseases in Twins↗

Haematopoietic cell lines capable of colonizing the thymus following in vivo transfer expressed T-cell receptor gamma-gene immature mRNA.

To clarify the mechanism by which progenitor T (pro-T) cells recognize and enter the thymus, an attempt was made to produce haematopoietic cell lines by the fusion of BALB/c nude mouse bone marrow or foetal liver cells (gestation 14 and 15 days) with AKR thymoma BW5147, thereby immortalizing cells with potency to colonize the thymus, a characteristic of pro-T cells rarely found in adult bone marrow or foetal liver. The hybridomas thus produced were classified according to the phenotype of surface markers, T-cell receptor (TcR) gene configuration and expression. All hybridomas were negative in the surface expression of T-cell markers such as TcR alpha beta, TcR gamma delta, CD3, CD4 and CD8. They had TcR beta-, gamma- and delta-genes, each with a different status with respect to configuration and transcription. Some possessed partially rearranged TcR genes and others expressed immature TcR mRNA. The cell lines were examined for their capacity to colonize the thymus following intravenous injection into recipient mice. It was found that the cells with capacity of colonizing the thymus expressed immature TcR delta mRNA, while the cell lines lacking TcR delta-genes did not home to the thymus. These findings imply that the potency for migrating to thymus is closely associated with the particular stage of prethymic cell differentiation which could be estimated by the analysis of TcR genes, and that some cell lines with the expression of TcR delta-gene mRNA and the ability to colonize the thymus are derived from pro-T cells.

Animals↗

[Mass-screening for ovarian cancer by means of transvaginal ultrasonography].

Since April, 1989 in Aomori Prefecture, mass-screening for ovarian cancer by means of transvaginal ultrasonography has been performed in a mass-screening car at the same time mass-screening for uterine cervical cancer. Subjects for this screening were self referred asymptomatic women 30 years of age or older. Real time ultrasonography was performed with a 5-MHz endovaginal transducer 5 sections for scanning were established by means of a transvaginal probe and all ultrasonic pictures obtained were recorded with an 8mm VTR. For women with abnormal ultrasonic findings, such as an ovary (tumor) over 30mm in size and massive ascites, a second screening or accurate examination was performed by retransvaginal ultrasonography, CT-scan, MRI and a combination assay of tumor markers. The results were as follows: The time required for the first screening, including bimanual examination, collection of Pap smear and ultrasonic examination, was about 60-70 seconds. The total number of screened women was 15,282, and 838 (5.5%) of them needed to receive the follow-up examinations. Laparotomy has been done for 48 women to date and 2 women were found to have premalignant and malignant ovarian tumors.

Adult↗