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Biomedical subjects

A Inoue

Publications and source records attributed to A Inoue.

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

Bromocriptine-induced morphological changes in cultured growth hormone-producing pituitary adenoma cells.

Tumor tissues obtained from two patients with growth hormone-producing pituitary adenomas were cultured and treated with bromocriptine, then examined for morphological changes. Untreated tumor cells (controls) were morphologically well preserved and in terms of growth hormone secretion. Tumor cells exposed to bromocriptine for 7 days contained many vacuoles, which, after 14 days of exposure, grew larger and more numerous. These vacuoles appeared to be extensions of endoplasmic reticulum: some were connected to rough or smooth endoplasmic reticulum or, occasionally, to Golgi apparatus, and there were ribosomes on their surfaces. Bromocriptine apparently has cytocidal effects on growth hormone-producing pituitary adenoma in vitro.

Adenoma↗
PubMed1989

The human preproendothelin-1 gene: possible regulation by endothelial phosphoinositide turnover signaling.

Preproendothelin-1 (ppET-1) mRNA has previously been demonstrated to be markedly induced in cultured endothelial cells (EC) by the addition to the medium of thrombin, an agent known to stimulate phosphoinositide turnover in EC. In this study, the mechanism of regulation of ppET-1 mRNA expression was investigated in cultured human umbilical vein EC by RNA blot analysis with cloned ppET-1 gene as a probe. The mRNA for ppET-1 was rapidly upregulated by O-tetradecanoylphorbol-13-acetate (TPA) (0.5 microM) and by ionomycin (5 microM) within 10 min of addition to the medium, but not by forskolin (50 microM). The rapid induction of ppET-1 mRNA by TPA or ionomycin occurred even in the presence of cycloheximide, indicating that the mRNA induction does not require de novo protein synthesis. The ppET-1 mRNA was an extremely unstable species of mRNA with an apparent half-life of about 15 min. However, the half-life of ppET-1 mRNA was not appreciably affected by TPA or ionomycin, suggesting that the mRNA induction by these agents is mostly due to an activation of the transcription of the mRNA. These observations indicate that the production of ET-1 in human EC can be controlled by a transcriptional gene regulation directly coupled to the intracellular signals from the phosphoinositide-turnover pathway, i.e., activation of protein kinase C and increase in intracellular Ca2+. These mechanisms are discussed in relation to information on the primary structure of cloned ppET-1 gene.

Blotting, Northern↗
PubMed1989

Free energy change in the elementary steps of actomyosin ATPase reaction.

We determined the rate constants of the elementary steps of actomyosin ATPase reaction, and calculated the effective free energy change in the elementary steps of ATPase reaction. It was shown that most of the free energy obtained by ATP hydrolysis is liberated in the step from the actomyosin-phosphate-ADP complex to actomyosin-ADP complex.

Actins↗
PubMed1989

[A case of Zollinger-Ellison syndrome successfully treated with an H+-K+ ATPase inhibitor].

A case of Zollinger-Ellison syndromes in a fifty year-old male that was successfully treated with a H+-K+ ATPase inhibitor (Omeprazol) is reported. The patient underwent a partial gastrectomy in 1984, but had been suffering from multiple refractory stomal and jejunal ulcers after the operation. In 1987, hypergastrinemia (760 pg/ml) was detected, and the presence of gastrinomas in the pancreatic head accompanied by a multiple liver metastasis was subsequently confirmed by CT-angiography and by the gastrin level detected in percutaneous, transhepatic, portal venous samples. A secretin provocation test proved to be negative, and the ulcers resisted the H2-receptor antagonists, but the patient was successfully cured shortly after the administration of an H+-K+ ATPase inhibitor.

Adenosine Triphosphatases↗
PubMed1989

Nuclear binding sites for reverse triiodothyronine in human placenta.

It has been generally believed that reverse triiodothyronine (reverse T3, rT3) is biologically inactive. Nevertheless the serum rT3 level is very high in fetal life, when the serum calcium level is higher than in the maternal. For this hypercalcemia in fetal life, there is no convincing evidence that any major calcium regulating hormone is responsible. And the assumption that rT3 may be concerned in active transport of calcium at placenta could be suggested. In this study nuclear protein was isolated from human placenta by extraction with 0.4M KCl buffer and binding studies utilizing radioactive rT3 were carried out. Scatchard analysis presented a curvilinear pattern, suggesting two classes of receptors: One with a association constant (Ka) of 1.14 X 10(8) M-1 and a limited capacity (Bmax) of 32.0 X 10(-15) mol/100 micrograms DNA and the other with Ka = 4.34 X 10(6) and Bmax = 454 X 10(-15). Its relative affinities for several thyroid hormone analogues were calculated. If the affinity for rT3 was assigned l, that for triiodothyronine would be 1/40, thyroxine: 1/63, Triiodothyroacetic acid: 1/18. Sulfhydryl agents affecting these binding characteristics were also studied. The Ka was not substantially changed but the Bmax was notably decreased by dithiothreitol (43%) and 2-mercaptoethanol (26%). In liver nuclei, the binding characteristics of rT3 receptor were analyzed for comparison. In this case only a single class of low affinity-high capacity rT3 binding site with a Ka of 6.69 X 10(6) was detected, a finding which was apparently different from those in placenta.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1989

[Malignant progression of oral leukoplakia].

The relation between oral leukoplakia and its malignant progression was clinicopathologically analysed by using the long-term follow-up cases treated in Cancer Institute Hospital, Tokyo, for 37 years (1950-1987). A total of 89 oral leukoplakia cases had been followed up for 11 years and 3 months on average, and the diagnosis of each case was histologically confirmed on biopsy. This series consisted of 56 male and 33 female patients. During the follow-up period, malignancy was found in 8 cases, at 5 years and 9 months on average after the diagnosis of leukoplakia. Among the cases being followed over 10 years, an incidence of malignant progression of benign leukoplakia was estimated as 10.25%. According to the size of leukoplakia, the lesions measuring over 1 cm in diameter showed higher risk for cancer development than the smaller ones. In the follow-up of leukoplakia, dysplasia was identified in 6 cases, and all of them were mild in degree. Moreover, cancer developed in 2 out of these 6 dysplasia cases.

Adult↗
PubMed1989

[A case of aortitis syndrome with left coronary ostial stenosis treated by aorto-coronary bypass grafting].

A 22 years-old woman who was suffered from effort angina caused by aortitis syndrome was hospitalized. The coronary arteriogram showed the left main trunk stenosis more than 99% with the visualization of the left anterior descending and left circumflex through the co-lateral vessels from right coronary artery. After successful sequential aorto-coronary bypass grafting to left anterior descending artery, the patient has been free from anginal pain.

Adult↗
PubMed1989

[The usefulness of immunologic methods for diagnosis and follow-up study of a case of pulmonary dirofilariasis].

Nearly 70 cases of dirofilariasis have been reported in Japan. A case operated for pulmonary dirofilariasis is reported, together with useful immunologic diagnostic and follow-up study. A 62-year-old woman was admitted to our hospital with complaints of cough and right chest pain. A chest X-ray film revealed a mass approximately 4 cm in diameter in the right S9 region. Histological examination of the mass by TBLB revealed necrotic tissue containing eosinophils and Charcot-Leyden crystals. Around the area of necrosis there was granuloma with infiltrating neutrophils, eosinophils and lymphocytes. Therefore, immunologic examinations were performed on the suspicion of a parasitic disease. Ouchterlony's test was done with positive reaction against Dirofilaria immitis antigen. Results of the ELISA indicated a high antibody titer (1:12800) to Dirofilaria immitis antigen. Histological examination of a surgically removed mass gave the final pathologic diagnosis of pulmonary dirofilariasis caused by Dirofilaria immitis. A follow-up study by ELISA revealed a remarkable decrease of the antibody titer to 1:3200 at 1 month after surgery, to 1:200 at 6 months and to negative after 9 months. These results suggest that the ELISA could be used to judge the healing of the disease by drug therapy. Thus immunologic studies by Ouchterlony's test and the ELISA were considered to be useful for the diagnosis and follow-up study of dirofilariasis.

Animals↗
PubMed1988

Cloning and sequence analysis of cDNA encoding the precursor of a human endothelium-derived vasoconstrictor peptide, endothelin: identity of human and porcine endothelin.

A cDNA encoding a human endothelium-derived vasoconstrictor peptide, endothelin, was isolated from a human placenta cDNA library. The nucleotide sequence of this cDNA clone showed that the primary structure of the human preproendothelin has 212 amino acid residues and is highly homologous to porcine preproendothelin, and that human endothelin is identical with porcine endothelin.

Amino Acid Sequence↗
PubMed1988

Agonist-induced substance P receptor down-regulation in rat central nervous system.

Rat brain slices were incubated with substance P (SP), and the SP receptors on the membranes from those slices were characterized by a 3H-SP binding technique. The number of substance P receptors measured in the extensively washed membrane preparations pretreated with 3 x 10(-5) M SP was reduced by 30% compared with that in nontreated membranes. This reduction was dependent on the incubation time and temperature. The metabolic inhibitors sodium azide and 2,4-dinitrophenol protected SP receptors from the reduction. The characteristics of 3H-SP incorporation into rat brain slices were similar to those of SP receptor down-regulation, that is, the 3H-SP incorporation was time, temperature, and energy dependent. Thus these results indicate that the processes of ligand incorporation and receptor down-regulation are closely associated phenomena. These observations may be important in elucidating the phenomenon of SP-induced desensitization.

Animals↗
PubMed1988

Primary structure, synthesis, and biological activity of rat endothelin, an endothelium-derived vasoconstrictor peptide.

Endothelin is a potent vasoconstrictor/pressor peptide, which we recently characterized from the conditioned culture medium of porcine aortic endothelial cells. We report here the cloning and partial sequencing of the rat endothelin gene. The nucleotide sequence predicted a 21-residue peptide similar to, but distinct from, porcine endothelin; 15 residues of rat endothelin were identical and 3 residues were substitutions by chemically similar amino acid residues to those in the porcine peptide. Synthetic rat endothelin was then prepared according to its deduced amino acid sequence. This synthetic peptide had (i) potent vasoconstrictor activity in the rat aortic strip and in perfused rat heart and (ii) a characteristically long-lasting in vivo pressor activity by intraaortic bolus injection in the conscious rat.

Amino Acid Sequence↗
PubMed1988

Retardation of the development of hypertension in DOCA salt rats by taurine supplement.

To study the antihypertensive effect of orally administered taurine in DOCA salt hypertension, urinary excretion of catecholamines, electrolytes, and arg-vasopressin was measured over four weeks in 20 taurine treated DOCA rats (group 1), 20 taurine untreated DOCA rats (group 2), and seven taurine untreated sham operated rats (group 3). Additional experiments were performed to determine whether or not the pressor and sympathetic responses to hypothalamic stimulation were altered after taurine treatment in DOCA rats. Systolic blood pressure decreased significantly in group 1 after the first week compared with that in group 2, and the differences became progressively more evident thereafter. At the fifth week the mean blood pressure was significantly lower in group 1 than in group 2, as was the heart rate. Although urinary excretion of adrenaline decreased significantly in group 1 at the first and fourth weeks, the difference in urinary excretion of noradrenaline between groups 1 and 2 was not significant. Urinary excretion of adrenaline and noradrenaline in group 3 was significantly lower than that in both hypertensive groups (groups 1 and 2). Urinary sodium excretion increased significantly in group 1 at the first and second week compared with group 2. With graded electrical stimulation of the ventromedial hypothalamus, resulting pressor and sympathetic responses were significantly smaller in group 1 than in group 2. These results suggest that the hypotensive effects of orally administered taurine in DOCA hypertensive rats are caused by suppression of the peripheral sympathetic nervous activity and by the resulting natriuresis.

Animals↗
PubMed1988

Production of eicosapentaenoic acid by marine bacteria.

About 5,000 strains of marine microorganisms were screened for eicosapentaenoic acid (EPA)-producing ability, which was detected in 88 of them. All of the latter were found to be obligate aerobic, Gram-negative, motile, short rod-shaped bacteria. One strain, designated as SCRC-8132, showed a doubling time of 30 min at 25 degrees C and produced 20 mg/liter (4 mg/g dry cells) when cultured in a P-Y-M-Glucose medium for 18 h. The EPA to total fatty acids ratio was 24%. The strain produced 26 mg EPA/liter (15 mg/g dry cells) when cultured at 4 degrees C for 5 days, the EPA ratio being increased to 40%.

Bacteria↗
PubMed1988

Reaction of two heads of gizzard myosin with ATP.

The reaction intermediates formed by the two heads of smooth muscle myosin were studied. The amount of myosin-phosphate-ADP complex, MPADP, formed was measured from the Pi-burst size over a wide range of ATP concentrations. At low concentrations of ATP, the Pi-burst size was 0.5 mol/mol myosin head, and the apparent Kd value was about 0.15 microM. However, at high ATP concentrations, the Pi burst size increased from 0.5 to 0.75 mol/mol myosin head with an observed Kd value of 15 microM. The binding of nucleotides to gizzard myosin during the ATPase reaction was directly measured by a centrifugation method. Myosin bound 0.5 mol of nucleotides (ATP and ADP) with high affinity (Kd congruent to 1 microM) and 0.35 mol of nucleotides with low affinity (Kd = 24 microM) for ATP. These results indicate that gizzard myosin has two kinds of nucleotide binding sites, one of which forms MPADP with high affinity for ATP while the other forms MPADP and MATP with low affinity for ATP. We studied the correlation between the formation of MPADP and the dissociation of actomyosin. The amount of Pi-burst size was not affected by the existence of F-actin, and when 0.5 mol of ATP per mol of myosin head was added to actomyosin (1 mg/ml F-actin, 5 microM myosin at 0 degrees C) most (93%) of the added ATP was hydrolyzed in the Pi-burst phase. All gizzard actomyosin dissociated when 1 mol of ATP per mol myosin head was added to actomyosin.(ABSTRACT TRUNCATED AT 250 WORDS)

Actomyosin↗