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H Nishimura

Publications and source records attributed to H Nishimura.

At least 631 records · Page 35Linked to original sources
PubMed1989

Angiotensin II vascular receptors in fowl aorta: binding specificity and modulation by divalent cations and guanine nucleotides.

In the domestic fowl, angiotensin (ANG) II causes a unique vasodepressor response in vivo and vascular relaxation of aortic rings in vitro that appear to be mediated by ANG II receptors. In initial studies using radioligand binding techniques, we identified specific vascular ANG II receptors in the fowl aorta. In the present study, we have characterized fowl vascular ANG II receptors in terms of binding specificity and their modulation by divalent cations and guanine nucleotide, to understand how the fowl receptor might differ from mammalian vascular ANG II receptors that mediate vasoconstriction. Competitive displacement of [125I] ANG II binding by ANG agonist and antagonist analogs revealed a unique pattern of receptor specificity, with the potency rank order: [Asn1, Val5]ANG II greater than [Asp1, Ile5]ANG II greater than [Asp1, Val5, Ser9] ANG I = [Asp1, Val5]ANG II much greater than [Val5]ANG III greater than [sarcosine(Sar)1, Ile5]ANG II greater than [Sar1, Ile8]ANG II much greater than [Sar1, Thr8]ANG II. Divalent cations (Ca++, Mg++ and Mn++) inhibited equilibrium radioligand binding by as much as 50% at 100 mM, with the potency order: Ca++ greater than Mn++ greater than Mg++. Mg++ and Mn++ stimulated binding very slightly (110%) at low doses (1-10 mM). The stable guanine nucleotide analog 5'-guanylyl imidodiphosphate inhibited equilibrium radioligand binding moderately (15% at 100 microM) in the presence of 10 mM MgCl2, but failed to alter the dissociation rate of receptor-bound ligand (half-time = 10.92 min). These results suggest that fowl vascular ANG II receptors exhibit specificity and regulatory properties fundamentally different from those of mammalian vascular ANG II receptors.

Angiotensin I↗
PubMed1989

Chicago sky blue and a helium neon laser abolish endothelium dependent relaxation in vivo in the microcirculation.

Chicago sky blue, also known as Niagara sky blue, is a vital dye that can successfully be used as an intravascular energy absorbing target for the light from a helium-neon (HeNe) laser. The result of this light/dye interaction is endothelium damage which can be controlled by adjusting the duration of the laser exposure and the amount of dye injected intravenously. The endothelial damage probably is the result of the heat generated by the dyes absorption of energy at the interface between plasma and endothelium. The most minimal damage resulted in selective loss of the dilation normally produced by acetylcholine and bradykinin, two endothelium dependent dilators. The dilation produced by sodium nitroprusside, a dilator acting directly on vascular smooth muscle, was preserved. More severe injury (i.e. more prolonged exposure to light and/or more dye, resulted in local platelet aggregation at the site of laser impact.

Acetylcholine↗
PubMed1989

[Current status of CDDP analogs in gynecologic malignancies].

Among the cooperative studies of cisplatin (CDDP) analogs in gynecologic malignancies in Japan, a phase III study of CBDCA in ovarian cancer was completed in 1988, while phase II studies of 254-S and DWA2114R are ongoing at the present time. Phase II preliminary data in ovarian cancer revealed a response rate of 25-38%, almost equi-effective and less toxic to that of CDDP. Approximately 20% response rate was achieved in CDDP refractory cases, in particular, responders were observed in mucinous and mesonephroid cases considered CDDP resistant. A phase III study of CBDCA in ovarian cancer, with a comparative study of CAP regimen suggested that CBDCA-containing regimen has an advantage of unnecessity of hydration, in spite of no significant differences response and toxicity. In the cancer of the uterine cervix, approximately 20% response rate was achieved. Of interest is that 254-S yielded a response of 60%, and the result suggested that the agent may have broad antitumor spectrums, different to that of CDDP.

Adolescent↗
PubMed1989

Identity of soluble thiamine-binding protein with thiamine repressible acid phosphatase in Saccharomyces cerevisiae.

Two secretory glycoproteins of S. cerevisiae, a soluble thiamine-binding protein and a thiamine-repressible acid phosphatase, were shown to be repressed to a similar extent by excess thiamine in the growth medium. Thiamine-repressible acid phosphatase was co-purified throughout the purification of the soluble thiamine-binding protein. Purified and deglycosylated soluble thiamine-binding proteins exhibited both thiamine-binding and acid phosphatase activities on non-denaturing polyacrylamide gel electrophoresis. Heat treatment of the purified soluble thiamine-binding protein caused a decrease in both activities with a similar inactivation profile. Two thiamine-repressible acid phosphatase-defective mutants isolated were found to be also defective in soluble thiamine-binding activity. The uptake of [14C]thiamine phosphate esters, such as thiamine monophosphate and thiamine pyrophsphate, was remarkably impaired in the mutant cells, whereas the uptake of [14C]thiamine by the mutant was almost the same with that by the parent strain. From these results, it was concluded that the soluble thiamine-binding protein is identical to the thiamine-repressible acid phosphatase in S. cerevisiae, which is involved in the hydrolysis of exogenous thiamine phosphate esters in the periplasmic space prior to the uptake of their thiamine moiety by yeast cells.

Acid Phosphatase↗
PubMed1989

[A case of "pure" progressive autonomic failure with impairment of cerebral blood flow autoregulation].

A 43-year-old male with "pure" progressive autonomic failure ("pure" PAF) was admitted to our hospital in June 1988, with a chief complaint of recent syncopal attacks while standing. Since the age of 35. He has noticed dyshidrosis on his left side. The family history was negative. Neurological examination showed dyshidrosis on his left side and profound orthostatic hypertension. No other neurological abnormalities were noted. Autonomic function tests revealed sympathetic and parasympathetic dysfunction as follows: Adrenaline administered subcutaneously gave a hyperactive pressor response from 136/82 mmHg to 190/116 mmHg with the pulse increasing from 54 to 150 beats per min. Hidrosis was observed on the right side of the body in response to heat. However, it was observed over the whole body in response to pilocarpine. In the studies of pupillary response to instillation of 1.25% epinephrine, both pupils were unchanged in diameter; after 5.0% tyramine, both pupils were dilated from 3.5 mm to 5.0; and after 2.5% methacholine, the right and left pupils, each originally 4.5mm were constricted to 3.5 mm and 4.0 mm, respectively. From the above data, this case was diagnosed as "pure" PAF. 133Xe inhalation method. The mean regional CBF (F1) values were reduced from 91 to 53 ml/100 g brain/min by postural change from supine to sitting position, associated with a decrease in mean arterial blood pressure (MABP) of 28 mmHg (from 103 to 75 mmHg). This result shows the impairment of CBF autoregulation in this patient. This case adds further evidence to the hypothesis that the autonomic nervous system plays a role in CBF autoregulation.

Adult↗
PubMed1989

[Plasma fibronectin in surgical patients].

Plasma fibronectin (PFN) was measured to clarify the role in patients who underwent major surgery. There was no statistical difference between male and female, benign and malignant disease, or more than 60 years old and less. Compared to the preoperative values of PFN, the postoperative ones showed significant decrease immediately after operation, this decrease was attributed to massive bleeding and prolonged surgical procedure. In contrast to the previous papers reporting as an opsonin, no such results were obtained. However, there was close relationship between PFN and antithrombin III, alpha 2-plasmin inhibitor, factor XIII, retinol binding protein and transferrin, which represent hemostasis, fibrinolytic system and nutritional status, respectively. To determine whether PFN acts as an opsonin, heparin (opsonin cofactor) was given to Wistar rats in various conditions. There was no significant difference between PFN in those rats and in controls. These results indicate that postoperative PFN is a good parameter of glycoprotein in hemostasis, fibrinolytic system, and rapid turnover protein, not of an opsonin.

Adult↗
PubMed1989

Immunosuppressive principles of Rehmannia glutinosa var. hueichingensis.

Separation of the immunosuppressive principles from Rehmanniae radix was done by monitoring hemolytic plaque-forming cells (HPFC) inhibitory activity to give two new phenethyl alcohol glycosides: jionosides A1 (4) and B1 (5), along with six known compounds: acetoside, isoacteoside, purpureaside C, echinacoside, and cistanosides A and F.

Animals↗
PubMed1988

Choline accumulation in isolated rat hepatocytes.

The accumulation of non-metabolized choline in isolated rat hepatocytes is concentrative in Na+ medium, whereas the accumulation does not exceed unity in a Li+ medium. Ouabain and 2,4-dinitrophenol inhibited the choline uptake. These results indicate that choline is taken up by rat hepatocytes via a Na+- and energy-dependent process, and choline oxidase is not directly connected with the choline transport system.

2,4-Dinitrophenol↗
PubMed1988

Identity of soluble thiamin-binding protein with thiamin-repressible acid phosphatase in Saccharomyces cerevisiae.

Two secretory glycoproteins of Saccharomyces cerevisiae, a soluble thiamin-binding protein and a thiamin-repressible acid phosphatase, were shown to be repressed to a similar extent by excess thiamin in the growth medium. Thiamin-repressible acid phosphatase was co-purified throughout the purification of the soluble thiamin-binding protein. Purified and deglycosylated soluble thiamin-binding proteins exhibited both thiamin-binding and acid phosphatase activity on non-denaturing polyacrylamide gel electrophoresis. Heat treatment of the purified soluble thiamin-binding protein caused a decrease in both activities with a similar inactivation profile. Furthermore, two thiamin-repressible acid phosphatase-defective mutants isolated had no and decreased soluble thiamin-binding activity, respectively. From the results, it was concluded that the soluble thiamin-binding protein is identical to the thiamin-repressible acid phosphatase in S. cerevisiae.

Acid Phosphatase↗
PubMed1988

Inactivation of the thiamine transport system in Saccharomyces cerevisiae with O-bromoacetylthiamine.

We have synthesized and characterized O-bromoacetylthiamine (BrAcThiamine), a new reagent for inactivating the thiamine transport system in Saccharomyces cerevisiae. A Lineweaver-Burk plot of data from the transport kinetic measurements showed that BrAcThiamine was a competitive inhibitor of thiamine transport in S. cerevisiae with a Ki value of 0.60 microM. Incubating BrAcThiamine with yeast cells at 40 degrees C in 0.05 M potassium phosphate buffer, pH 5.0, caused concentration- and time-dependently a remarkable loss of thiamine transport activity. The inactivating reaction of yeast thiamine transport by BrAcThiamine proceeded most effectively at pH 5.0, coinciding with the optimal pH of the transport activity. Thiamine and thiamine analogs (pyrithiamine and O-acetylthiamine) protected yeast thiamine transport activity against the inactivation by BrAcThiamine. In addition, it was found that a membrane fraction prepared from yeast cells treated with BrAcThiamine had a thiamine-binding activity only 20% of that from control cells without inactivating the binding activity of the soluble fraction. These results suggest that BrAcThiamine inactivates the uptake activity by irreversible binding to the binding site of carrier protein(s) in the thiamine transport system.

Biological Transport↗
PubMed1988

Angiotensin II receptors in the fowl aorta.

In the domestic fowl, angiotensin II (ANG II) causes an in vivo depressor response and in vitro relaxation of aortic rings which appear to be a direct action of ANG II on the blood vessels. Thus, we determined whether binding sites specific to ANG II exist in the membrane fraction of the fowl aorta. The particulate fraction of aortas from adult female fowl, Gallus gallus, exhibits high specific binding to ANG II ligand. 125I-[Ile5]ANG II (0.5 nM) binding to the above fraction (30 micrograms protein) in 50 mM Tris (pH 7.2), 10 mM MgCl2, and 0.2% bovine serum albumin at 12 degrees (1) is rapid, saturable, and reversible; (2) increases as a function of ligand or membrane concentration, time, and temperature; and (3) optimally fits to a two-site (high and low affinity) model. The equilibrium dissociation constant (0.15 +/- 0.03 nM) and binding site concentration (28.7 +/- 8.1 fmol/mg protein) of the high affinity site as well as association (0.055 nM-1.min-1) and dissociation (0.0122 min-1) rate constants are similar to those of mammalian vascular ANG II receptors. Both 125I-[Ile5]ANG II and 125I-[Val5]ANG II are competitively displaced by unlabeled ANG II. These results suggest that specific ANG II receptors exist in the fowl aorta.

Angiotensin II↗
PubMed1988

The modified forced-swim test in rats: influence of rope- or straw-suspension on climbing behavior.

We modified Porsolt's forced-swim test by suspending ropes or straws above the water in order to investigate a possible relationship between immobility and perceived escape responses from water. In this modified test, it was demonstrated clearly that rats reduced their duration of immobility and attempted to climb up the suspended ropes or straws. Most rats which had remained immobile during a 5-min test period in the forced-swim test, exhibited such climbing responses within 5-10 min of rope-suspension. Despite the suspension of ropes, however, some rats showed immobile postures and did not respond to the rope. On the other hand, straws were used in order to produce sliding and prevent climbing when the animals attempted to climb. There were no differences in immobility during either rope- or straw-suspension. It seems that the climbing behavior displayed by forced-swimming rats is due to a "pseudo-escape" effect produced by the suspension of an object above the water. The present findings were interpreted as further evidence for the notion that immobility in forced-swimming rats does not necessarily imply "behavioral despair," but rather an emotional reaction to an inescapable stressor.

Animals↗
PubMed1988

Is immobility of rats in the forced swim test "behavioral despair"?

Rats were forced to swim in a cistern until sinking in order to examine the possible relationship between sinking and immobility which has been reported to reflect "behavioral despair" in the forced swim test. Rats were classified into sinking and non-sinking groups, according to the appearance of sinking behavior over a 2 hr test. The sinking rats showed significantly shorter immobility times during the first 15 min as compared to the non-sinking rats. Therefore, sinking behavior seems to be a sign of emotional behavior such as fear and/or anxiety accompanied by defecation. Discriminant analysis showed that the immobility time during the first 15 min was a prediction of sinking. These findings suggest that the rapidly induced immobility in this forced swim test reflects the possibility of floating behavior in connection with the emotional reaction.

Animals↗
PubMed1988

Ampicillin concentrations in human serum and periodontal membrane following a single oral administration of talampicillin.

1. Ampicillin concentrations in human serum and periodontal membrane after a single oral administration of talampicillin (500 mg) were assayed by the agar diffusion (paper disc) method. 2. The peak times of serum and periodontal membrane were identical, being 150 min after administration. 3. The peak concentrations of serum and periodontal membrane were 7.81 micrograms/ml and 4.11 micrograms/g, respectively. 4. The mean ratio of periodontal membrane to serum concentration at the peak time was 0.53.

Administration, Oral↗
PubMed1988

Binding and tyrosine kinase activities of the insulin receptor on Epstein-Barr virus transformed lymphocytes from patients with Werner's syndrome.

To assess the abnormalities of insulin receptor in patients with Werner's syndrome, we established Epstein-Barr virus transformed lymphocytes and studied the binding as well as kinase activities of insulin receptor. The insulin binding to both intact cells and WGA-purified insulin receptor preparations was within normal range. Autophosphorylation of the beta-subunit was not altered in patients with Werner's syndrome, and the receptors of these patients phosphorylated an exogenous substrate to a degree comparable to that of the normal participants. Taken together, these findings indicate that insulin resistance in Werner's syndrome likely is caused by a defect that cannot be detected by means used in the present study.

Adult↗