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Biomedical subjects

K Goto

Publications and source records attributed to K Goto.

At least 793 records · Page 44Linked to original sources
PubMed1987

Dural fistulas involving the transverse and sigmoid sinuses: results of treatment in 28 patients.

Twenty-eight symptomatic dural fistulas involving the transverse and sigmoid sinuses were treated between 1978 and 1986 with a variety of treatment modalities. Occipital artery compression therapy resulted in a complete cure in two of nine patients (22%) and improvement in three of nine (33%). There were no complications from this treatment. Patients who were excluded or in whom compression therapy failed were treated with embolization alone or in conjunction with surgery. Of the 17 patients who underwent embolization alone, ten were cured and six were improved. Six patients had a combination of embolization and surgery; four patients were cured and two improved. There were three complications in this series, one related to surgery and two related to embolization.

Adult↗
PubMed1987

Neurokinin A as a potent bronchoconstrictor.

Neurokinin A (NKA) and B (NKB) were more potent bronchoconstrictive agents than substance P (SP) in guinea pig tracheal strips. The content of NKA in guinea pig lung homogenate was 2.26 +/- 1.09 pmol/g wet lung, which was approximately half that of SP (4.46 +/- 1.33 pmol/g wet lung); NKB was not detected in the guinea pig lung homogenate (less than 0.01 pmol/g wet lung). Histologically, NKA-immunoreactive fibers were distributed in the bronchial smooth muscle layers. Pulmonary arteries and veins were also found to be innervated by NKA-immunoreactive nerves. In addition, a few fibers were observed in the trachea, bronchioles, and alveoli. These findings suggest that NKA may be one of the neurotransmitters of the noncholinergic bronchoconstrictive nerves.

Animals↗
PubMed1987

[Pharmacological study of TJ-8007 (Tsumura-Zokumeito) (I): Protective effects of TJ-8007 against anoxic brain damage].

The protective effects of TJ-8007 (Tsumura-Zokumeito, Traditional chinese medicine) against cerebral anoxia were investigated with various experimental models in mice and rats. 1) In histotoxic anoxia, TJ-8007 (0.3-3.0 g/kg, p.o.) dose-dependently demonstrated a protective effect on coma induced by a sublethal dose of KCN (1.8 mg/kg, i.v.) in mice. Ifenprodil (30 mg/kg, p.o.) tended to reduce the coma time, but papaverine (100 mg/kg, p.o.) showed a negative effect. 2) TJ-8007 (0.3-3.0 g/kg, p.o.) dose-dependently tended to prolong the survival time of mice subjected to a lethal dose of KCN (3.0 mg/kg, i.v.), TJ-8007 also improved the survival rate at the dose of 3.0 g/kg. Ifenprodil (30 mg/kg, p.o.) or papaverine (100 mg/kg, p.o.) exerted a similar effect on the survival time, but did not affect the mortality. 3) In the normobaric hypoxia with a gas mixture of 96% N2 and 4% O2, TJ-8007 (0.3-3.0 g/kg, p.o.) did not affect the survival time of mice. On the other hand, papaverine (100 mg/kg, p.o.) prolonged the survival time, and phenytoin (100 mg/kg, p.o.) showed a marked protective effect, but ifenprodil (30 mg/kg, p.o.) produced an adverse effect. 4) In the asphyxic anoxia induced by stopping artificial respiration of immovable rats, TJ-8007 (1.0, 3.0 g/kg, p.o.) showed a protective effect on the fall of systemic blood pressure and on the decline of heart rate; furthermore, it dose-dependently prolonged the disappearance time of cortical activity. Also, phenytoin (100 mg/kg, p.o.) tended to protect against the fall of blood pressure and prolonged the cortical resistance time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

A triplet pregnancy after gonadotropin-releasing hormone pulsatile infusion therapy in a postoperative case of growth hormone-producing pituitary macroadenoma.

Intravenous GnRH pulsatile infusion therapy (10 micrograms/pulse, 90-min interval) was conducted in an acromegalic patient from whom 2/3 of a GH-producing pituitary macroadenoma had been removed. Before infusion therapy, plasma levels of GH and PRL were 10-20 and 15-25 ng/ml, respectively, while those of LH and FSH were subnormal without intrinsic fluctuations. Ovulation was induced after 13 days of infusion which was terminated on the 23rd day of therapy. Luteal function was supported by hCG (5,000 IU per dose) which was given 4 times from the 23rd to the 31st day of the treatment cycle. Triplet pregnancy was diagnosed ultrasonographically within 7 weeks of gestation. Although GH and PRL levels increased gradually as the gestational period progressed and plasma levels of GH and PRL of 32-55 and 30-67 ng/ml, respectively, were detected after 30 weeks of gestation, neither adverse signs related to the enlargement of the residual pituitary tumor nor manifestation of acromegaly was observed. The immunoreactive somatomedin-C levels during this period were not greater than those in normal pregnant women. Caesarean section was performed at 34 weeks and 3 normal healthy infants were delivered. Detailed analyses of hormonal changes throughout the period of GnRH pulsatile infusion and subsequent luteal phase revealed that the triplet pregnancy had been induced by the GnRH therapy itself and that hCG stimulation did not play any critical role. The residual tumor mass secreted increasing amounts of GH during the latter period of pregnancy but the somatomedin-C levels were not associated with this elevation. Therefore, the clinical as well as the hormonal findings strongly suggested that the GH secreted in increasingly large amounts by the residual tumor mass during pregnancy was defective in certain biological properties.

Adenoma↗
PubMed1987

Intramural nerve-mediated inotropic responses of left atria of rats and guinea pigs: demonstration of alpha adrenergic and nonadrenergic noncholinergic responses in guinea pigs.

The effects of transmural nerve stimulation (TNS) on contractile responses of rat and guinea pig atria were analyzed pharmacologically. Isolated left atria were electrically driven through AgAgCl field electrodes and TNS was performed by brief introduction of defined stimulation patterns through the same electrodes. Step elevations in stimulating voltage induced biphasic inotropic responses in the left atria of both species: an initial negative component which was usually overwhelmed by a subsequent positive one. The transient negative inotropic response was induced by parasympathetic cholinergic nerve excitation, inasmuch as it was abolished by atropine. In the left atrium of the rat, the TNS-induced positive inotropic response was due exclusively to adrenergic nerve excitation through activation of beta-1 adrenoceptors. In contrast, analysis of the time course of responses in guinea pig left atria after nerve stimulation at 10 Hz revealed a positive inotropic response consisting of two phases; rapid and delayed phases were superimposed upon each other. The rapid phase was reduced by atenolol, a beta-1 antagonist, and attenuated further by prazosin, an alpha-1 antagonist. In the presence of both atenolol and prazosin, TNS of guinea pig left atria still induced a positive inotropic response but it had a slow onset and decay. This is termed the delayed phase response. TNS induced a similar delayed inotropic response in atria from surgically sympathectomized or reserpine-pretreated guinea pigs, from which catecholamine-fluorescence nerves and responses to tyramine were absent. These results demonstrate that TNS excitated adrenergic, cholinergic and nonadrenergic noncholinergic nerves in guinea pig left atria.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1987

Role of calcitonin gene-related peptide as cardiotonic neurotransmitter in guinea pig left atria.

A potential neurotransmitter role of calcitonin gene-related peptide (CGRP) in nonadrenergic noncholinergic (NANC) nerves was examined in the left atrium of guinea pigs. In the presence of atenolol (beta-adrenoceptor antagonist), prazosin (alpha adrenoceptor antagonist) and atropine (muscarinic antagonist), transmural nerve stimulation (TNS) elicited a positive inotropic response which was slow in both onset and decay. Inasmuch as this TNS-induced positive inotropic response was abolished by tetrodotoxin, it can be considered that the response was mediated by intracardiac NANC nerves. Numerous CGRP-like immunoreactive nerves were detected in the left atrium. Exogenously applied CGRP produced a positive inotropic response in a dose-dependent manner. Neither substance P nor vasoactive intestinal polypeptide exerted a positive inotropic effect. CGRP-like immunoreactive nerves and the TNS-induced NANC response was not affected by surgical sympathectomy of the heart or reserpine pretreatment but were specifically abolished by the pretreatment of animals with capsaicin. These results suggest that CGRP is the potential neurotransmitter of NANC nerves in the left atrium of guinea pigs.

Animals↗
PubMed1987

Enhancement of host defence by Y-19995 (2,4'-bis(1-methyl-2-dimethyl-aminoethoxyl)-3-benzoylpyridine dimaleate), a novel synthetic compound. I. Accelerated restoration from the leukocytopenia and augmented protection against microbial infections in immunocompromised mice.

Effects of a novel synthetic compound, Y-19995, on the host defence in immunocompromised mice were investigated in terms of the restoration of leukocytopenia and the protection against several microbial infections. Oral or intravenous administration of Y-19995 into mice after X-irradiation, treatment with cyclophosphamide or mitomycin C prevented the leukocytopenia to some extent and promoted the restoration in cell numbers of both the peripheral blood leukocytes and bone marrow. Intravenous administration of Y-19995 increased significantly the survival rates of X-ray irradiated mice against acute systemic infections with Escherichia coli, Pseudomonas aeruginosa and Candida albicans, and intramuscular infection with Escherichia coli. The clearance of Escherichia coli from the blood of X-ray irradiated mice was also promoted by the treatment with Y-19995. The augmented protection against microbial infections in immunocompromised hosts by Y-19995 may be attributed mainly to the prevention of leukocytopenia or the enhanced restoration from leukocytopenia.

Animals↗
PubMed1987

Unsaturated fatty acids in mammalian cell strains cultured for more than 10 years in serum-free synthetic media.

In cultured cells, essential lipids are usually supplied by the serum added to the culture medium. However, in a serum-free medium, essential lipids would need to be synthesized by the cells. Cell strains derived from kidney, spleen, uterine carcinoma and fibroblasts were cultured in serum-free synthetic media for more than 10 years and their fatty acids were analyzed capillary column gas-liquid-chromatography. The following conclusions were drawn: 1. Polyunsaturated fatty acids were not detected. Thus, prostaglandins are not appear to be essential for initiation of DNA synthesis in these cells. 2. A compensatory increase of the content of monounsaturated fatty acids was detected. 3. A large difference in vaccenic/oleic acid ratio was found among several strains of cells, but the ratio does not reflect that of the original tissues.

Animals↗
PubMed1987

Inhibitory effect of calcitonin gene-related peptide on excitation and contraction of smooth muscles of the rat vas deferens.

Calcitonin gene-related peptide (CGRP) inhibits the twitch response of the rat vas deferens induced by nerve stimulation. Inasmuch as CGRP-like immunoreactive nerves were demonstrated to be present in the rat vas deferens, the effect of CGRP on the contractile activity of the tissue was pharmacologically and electrophysiologically analyzed in vitro. The twitch response of the vas deferens induced by transmural nerve stimulation was inhibited by rat CGRP, porcine CGRP and human CGRP (hCGRP). Both ED50 values and the extent of the maximum inhibition of the twitch response were the same for these CGRP groups. hCGRP (10(-8) to 10(-7) M) hyperpolarized the resting membrane potential of smooth muscle cells but did not affect the amplitude of excitatory junction potentials induced by nerve stimulation. Neither the frequency of occurrence nor the amplitude of spontaneous junction potentials were affected by hCGRP. The threshold potentials for the generation of action potentials were less negative in the presence of hCGRP. hCGRP reduced slightly the contraction of the tissue induced by norepinephrine and by adenosine 5'-triphosphate. hCGRP reduced markedly the contractions induced by direct electrical stimulation of both denervated and normal tissues in the presence of tetrodotoxin. These results indicate that CGRP does not affect the release of a sympathetic neurotransmitter. CGRP appears to attenuate the contraction of the rat vas deferens through suppression of both the excitability and excitation-contraction coupling of the smooth muscle.

Action Potentials↗
PubMed1987

Effect of capsaicin on smooth muscles of rat vas deferens: involvement of calcitonin gene-related peptide?

The effect of capsaicin on the rat vas deferens was examined in relation to the role of endogenous calcitonin gene-related peptide (CGRP) in modifying the contractility of smooth muscles. Capsaicin attenuated the twitch response of the rat vas deferens induced by the transmural nerve stimulation (TNS) in vitro. The effect of capsaicin was transient and developed tachyphylaxis rapidly. Capsaicin inhibited the contraction induced by the direct electrical stimulation of the innervated tissues in the presence of tetrodotoxin but not of the surgically denervated tissues. CGRP-like immunoreactive nerves were demonstrated to be present in the rat vas deferens. Exogenously applied CGRP inhibited both the TNS-induced twitch response and the contraction induced by direct electrical stimulation. Both capsaicin and CGRP slightly hyperpolarized the resting membrane potential of smooth muscle cells but did not affect the amplitude of the excitatory junction potentials. The intensity of CGRP-like immunoreactivity was reduced markedly after the in vitro incubation of the tissue with capsaicin. No CGRP-like immunoreactive nerves were detected in the denervated tissues. Thus, capsaicin inhibited both the TNS-induced twitch response and the contraction induced by direct stimulation of the smooth muscles only when CGRP-like immunoreactive nerves were normally present. These results suggest that capsaicin releases endogenous CGRP and that the released CGRP inhibits the contraction of the rat vas deferens by acting directly on smooth muscle cells but not on the sympathetic nerves.

Animals↗