Biomedical subjects

N Shibuya

Publications and source records attributed to N Shibuya.

At least 109 records · Page 6Linked to original sources

PubMed1990

[Effects of ketamine on voltage-dependent Ca2+ current in single smooth muscle cells from rabbit portal vein].

The effects of ketamine on membrane potentials and voltage-dependent Ca2+ current were studied in dispersed single smooth muscle cells from rabbit portal vein. The resting membrane potential (-56.2 +/- 1.5mV) was not affected by ketamine (10(-5)-10(-3)M). The duration and the amplitude of the action potential evoked by intracellular stimulation were significantly decreased by ketamine in the concentrations of 10(-4)M and 10(-3)M. Voltage-gated Ca2+ current in single smooth muscle cells was apparently decreased by ketamine at concentrations of between 10(-5)M to 10(-3)M. The activation threshold of Ca2+ current (approx. -30mV) was also decreased by ketamine. Therefore, these results suggest that inhibition of the contractile response by ketamine in vascular smooth muscle from rabbit portal vein may be attributable to the inhibition of the Ca2+ current.

Animals↗

PubMed1990

[CT of gold pneumonitis].

We experienced five cases of gold pneumonitis. CT findings of four cases and pathological findings of an autopsy case were discussed. CT findings of gold pneumonitis could be classified as follow; (1) high density shadow of subpleural zone-BOOP suspected- (2) high density shadow along the broncho-vascular bundle (3) small cystic shadow of subpleural zone-UIP. Histological findings of an autopsy case revealed the fibrosis along the broncho-vascular bandle. A variety of radiologic and pathologic feature on the gold pneumonitis were seen.

Adult↗

PubMed1990

[A case report of anesthesia for concomitant right pneumonectomy and coronary artery bypass operations].

A 61-year-old man with previous myocardial infarction, was diagnosed as having lung cancer. Coronary arteriogram revealed stenoses of left anterior descending artery. We did the concomitant pulmonary and cardiac operations. Anesthesia was induced with fentanyl 1.5 mg and pancuronium 6 mg. A 37 Fr double-lumen endotracheal tube was inserted. Then a pulmonary artery catheter was inserted. The patient was given nitroglycerin for prevention of myocardial ischemia. The tumor had invaded pulmonary artery and therefore right pneumonectomy was necessary. After resection of right lung, coronary artery bypass operation was performed. On weaning from cardio-pulmonary bypass, pulmonary artery pressure increased to 48/20mmHg. Therefore he required dopamine and dobutamine each 4 micrograms.kg-1.min-1 for weaning. But we experienced no serious complications such as hypoxemia or perioperative myocardial infarction.

Anesthesia↗

PubMed1989

Molecular-genetic study of Duchenne and Becker muscular dystrophies: deletion analyses of 45 Japanese patients and segregation analyses in their families with RFLPs based on the data from normal Japanese females.

This study consisted of 1) molecular deletion analyses in patients with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) using the entire cDNA for the DMD gene as hybridization probes, 2) RFLP analyses in a large number of Japanese normal women using 11 DMD-linked cloned DNAs as probes, and 3) segregation analyses with these RFLP data in 17 DMD families in which prenatal or carrier diagnosis was required. The deletion study showed that 18 (43%) of 42 male DMD patients had a deletion within the DMD gene, while no detectable deletion was found in 3 BMD patients. These deletions were preferentially observed at the 5' end of the DMD gene, while no deletion was found in the 3' portion of the gene. Of a total of 15 RFLPs detected with the 11 probes, one was a new RFLP (probe/enzyme: P20/MspI). In 6 RFLPs, the allele frequencies in the Japanese were statistically different from those in the Caucasian. Based on the RFLP data combined with the result of the deletion study, an estimated diagnostic rate for prenatal diagnosis and/or carrier detection in the Japanese DMD families was 63%. The real diagnostic rate obtained from the prenatal and carrier diagnoses, which were practically performed in 17 families, corresponded to the estimation. A protocol useful for the diagnosis in Japanese DMD families is presented.

Chromosome Deletion↗

PubMed1989

A comparative study of bark lectins from three elderberry (Sambucus) species.

Three elderberry lectins isolated from the bark of three different species of the genus Sambucus which are native to Europe (S. nigra), North America (S. canadensis), and Japan (S. sieboldiana) were studied comparatively with regard to their carbohydrate binding properties and some structural features. All three lectins contained two identical carbohydrate binding sites per molecule and showed a very high specificity for the Neu5Ac(alpha 2-6)-Gal/GalNAc sequence. However, relative affinities for various oligosaccharides were significantly different among them, suggesting differences in the detailed structure of the carbohydrate binding sites of these lectins. The three lectins were immunologically related, but not identical, and all were composed of hydrophobic and hydrophilic subunit regions, although the molecular sizes of these subunits were slightly different among the three lectins. N-terminal sequence analysis of the subunits of these lectins suggested that they have a very similar structure in this region but also indicated the occurrence of N-terminal processing such as the deletion of several amino acid residues at the N-termini for both hydrophobic and hydrophilic subunits of all three lectins. Tryptic peptide mapping of the three lectins showed a similar pattern for all of them but also showed the presence of some unique peptides for each lectin.

Amino Acid Sequence↗

PubMed1989

Immunochemical and structural characterization of a serotype-specific polysaccharide antigen from Actinobacillus actinomycetemcomitans Y4 (serotype b).

A serotype-specific polysaccharide antigen of Actinobacillus actinomycetemcomitans Y4 (serotype b) was extracted from whole cells by autoclaving. The extract was purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300 columns. The purified polysaccharide antigen formed a single precipitin line with anti-type b serum but not with anti-type a serum and anti-type c serum. The antigen was composed of 43.9% L-rhamnose, 49.1% D-fucose, and a trace amount of fatty acid. Methylation analysis, Smith degradation, and optical rotation data showed that the antigen was a polymer consisting of a disaccharide repeating unit, ----3)-alpha-D-fucopyranosyl-(1----2)-beta-L-rhamnopyranosyl-(1----. In quantitative precipitin inhibition tests, D-fucose and L-rhamnose showed very low inhibition, but the partial hydrolysate of the purified antigen was an effective inhibitor, suggesting that the serotype b specific antiserum recognizes the larger oligosaccharide units.

Actinobacillus↗

PubMed1989

Characteristics of in vitro passaged cells derived from a rat transplantable malignant fibrous histiocytoma.

Morphologic and functional characteristics were investigated on in vitro passaged cells (MT-P) derived from a rat transplantable malignant fibrous histiocytoma (MFH-MT). There were spindle, polygonal, and giant cell types in MT-P. Ultrastructurally, the polygonal and giant cells had the abundant cytoplasm with many lysosomes and processes, whereas the spindle cells possessed smooth cell surface and a small number of lysosomes in their cytoplasm. Immunorosette formation for Fc- and C3-surface receptors and phagocytic activity were demonstrated in 10-20% of MT-P. MT-P were positive for acid phosphatase, nonspecific esterase and alkaline phosphatase. Chromosomes counted in 100 MT-P ranged from 32 to 100 with two peaks of 64 and 76. Tumors induced in syngeneic rats by inoculating MT-P showed variable histologic patterns. They were composed partly of histiocytic cells arranged in a compact sheet. Fibroblastic cells often arranged in a storiform pattern or were supported by myxoid matrix. Osteosarcoma-like structures were occasionally found in the tumors. These results suggest that MFH-MT is heterogeneous, although some cells constituting the tumors have histiocytic markers.

Animals↗

PubMed1989

[Nasal cavity paraganglioma with intracranial extension. Case report].

A 58-year-old male was admitted following an episode of unconsciousness. Nine years prior to this, he had undergone surgery and radiation therapy for a nasal tumor. Subsequently, he had undergone surgical excision of recurrent nasal tumors and metastases to the cervical lymph nodes. The final pathological diagnosis was paraganglioma. On admission, he had no neurological deficit other than anosmia. Laboratory studies showed no abnormalities in urinary concentrations of vanillylmandelic acid or catecholamines. Computed tomography (CT) demonstrated a calcified, heterogeneously enhanced mass in the anterior ethmoid sinus and bilateral frontal fossa. Cerebral angiography revealed a mesh-like tumor stain. Through a bifrontal craniotomy the intracranial tumor was totally removed. It was hypervascular and clearly demarcated from the surrounding cerebral tissue. The pathological diagnosis was paraganglioma without malignant features. Radiation therapy was administrated postoperatively at a total dose of 5060 rads, and follow-up CT showed regression of the ethmoid sinus tumor. As of 2 years postoperatively, the tumor has not recurred.

Brain Neoplasms↗

PubMed1989

Indications for cisternal drainage in conjunction with early surgery in ruptured aneurysms and timing of its discontinuation.

The efficacy of cisternal drainage in association with early aneurysmal surgery remains highly controversial. The authors attempted to clarify the indications for this procedure and the proper timing of drainage removal in a series of 205 patients with no evidence of intracerebral hematoma who underwent surgical obliteration of bleeding aneurysms within 72 hours after subarachnoid hemorrhage. The 136 patients in whom cisternal drainage was performed constituted Group A and the remaining 69 patients Group B. The acid-base balance and lactate concentration were measured serially in cisternal cerebrospinal fluid (CSF) and arterial blood of 33 patients. Subarachnoid blood demonstrated by computed tomography (CT) was graded according to the system of Fisher et al. The outcome at 6 months did not differ significantly between Groups A and B among patients of preoperative CT grade 2 and clinical grades I-II. However, among patients of CT grade 3 or clinical grade III, those in Group A had better outcomes. The rates of symptomatic vasospasm in Groups A and B were 39.7% and 40.6%, respectively. However, persistent vasospasm was more frequent in Group B (11.8% vs. 26.1%), particularly in CT grade 3 patients. Ventricular enlargement was more prevalent in Group A (33% vs. 17%). CSF pH higher than arterial pH after the 7th postoperative day was associated with a poor outcome and was fairly well correlated with a rise in CSF HCO3- and a fall in CSF PCO2. CSF lactate increased with clinical deterioration but was not well correlated with preoperative CT findings, total volume of CSF outflow, or prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

[Peripheral superior cerebellar artery aneurysm. Case report].

The patient, a 37-year-old female, was hospitalized with a severe headache. Neurological examination on admission revealed no deficits except for neck stiffness and somnolence. Computed tomography showed a subarachnoid hemorrhage, which was especially prominent in the supracerebellar and quadrigeminal cisterns, but demonstrated no ventriculomegaly. Cerebral angiography on admission revealed no apparent abnormalities, but repeat angiography 8 days later disclosed a saccular aneurysm (2 X 3 mm) arising from the hemispheric branch of the left superior cerebellar artery (SCA). Three days after admission, the patient developed cerebellar dysarthria, which was assumed to be due to vasospasm. On the 24th day after admission, the aneurysm was successfully clipped through the infratentorial-supracerebellar approach. The postoperative course was uneventful and the patient was discharged with no neurological deficit. Nineteen other cases of peripheral SCA aneurysm have been reported in the literature. The presence of this type of aneurysm should be considered in patients who are fairly young and have focal neurological signs, such as third or fourth nerve palsy and/or cerebellar dysfunction. The prognosis for such patients is good, except in cases in which the neurological status is poor at the onset.

Adult↗

PubMed1989

[Strategy for molecular diagnosis of Duchenne muscular dystrophy: alleles frequency in RFLPs detected with X-linked probes in normal Japanese].

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder. Recently it has been suggested that the protein named "dystrophin" is not produced in the DMD muscle because of their mutant of defective DMD gene. Recent molecular studies using subclones from the DMD-cDNA as probes revealed a DNA deletion in about a half of the DMD patients. Since not all patients showed deletion, segregation analysis with restriction fragment length polymorphisms (RFLPs) is still necessary and important for diagnosis not only patients but female carriers as well. Therefore, we tried to detect RFLPs with the use of many probes localized within and/or flanked with the DMD gene and made a protocol for the diagnosis with our RFLP data. Among 50 normal Japanese females, the frequencies of rare alleles which identified with enzyme/probe combinations in each were as follows (RFLPs practically available for diagnosis are underlined): 0.38 for p782/EcoRI; 0.14 for p99-6/Pst I: 0.45 for pJ66-HI/Pst I: 0.16 for pERT87-30/Bgl II; 0.44 for 87-15/Xmn I: 0.07 for 87-15/Taq I; 0.33 for 87-8/Taq I; 0.44 for 87-1/Xmn I; 0.45 for 87-1/Mva I; 0.43 for Xj-1.1/Taq I; 0.34 for 754-11/EcoR I; 0.41 for 11.28/Taq I. Some of our results were different from the Caucasian both on the allele frequencies and the restriction fragment length. We proposed a diagnostic protocol of DMD and it's carriers in Japan. Firstly, segregation analysis should be performed with five different combinations of double probe/enzyme, such as Yj-1,.1/L1.28/Taq I, ERT87-1/87-15/Xmn I, 87-1/Mva I, J66-HI/99-6/Pst I, and 782/754-11/EcoR I.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

PubMed1989

Craniopharyngioma with extension into the cerebellopontine angle. Case report.

A rare case of craniopharyngioma which extended from the suprasellar region into the cerebellopontine angle (CP angle) is reported. This patient, a 18-year-old man who underwent two surgeries for suprasellar craniopharyngioma did not show recurrence during interval studies. However, nine years after the second surgery CT scan and MRI indicated a left CP angle mass when he was submitted to suboccipital craniectomy and tumor resection. He had been on human growth hormone (hGH) regimen for his pituitary dwarfism before tumor recurrence. The authors speculate retrospectively that the tumor growth in the left CP-angle was correlated with hGH therapy in this particular case.

Adolescent↗

PubMed1988

[Impaired vasopressin secretion in patients with myotonic dystrophy].

Hypernatremia has occasionally been observed in patients with myotonic muscular dystrophy (MyD). To elucidate the possibility of osmoregulatory dysfunction, we investigated hypothalamo-posterior pituitary function as well as serum electrolytes in eight patients with MyD. Blood samples were obtained early in the morning after overnight dehydration. Renal function was estimated by blood urea nitrogen, serum creatinine and creatinine clearance. Posterior pituitary function was evaluated by direct measurement of plasma vasopressin (AVP) during a 5% hypertonic saline infusion. Plasma AVP concentrations were determined by sensitive radioimmunoassay. In five patients, circulating blood volume (CBV), plasma renin activity (PRA) and serum aldosterone (S-Aldo.) were also measured. The mean serum sodium level (143.9 +/- 1.7mEq/1: Mean +/- SD) was significantly higher than in the controls (139.4 +/- 2.2mEq/1). A 5% hypertonic saline infusion showed a subnormal increase in AVP and diminished thirst, despite sufficient elevation of plasma osmolality, in all patients as compared with healthy adults. Renal function was intact. Biochemical evidence of dehydration, estimated by PRA, S-Aldo and CBV, was unremarkable in four of the five patients. These findings suggest that patients with MyD have neurogenic disorders of osmoregulation in addition to previously reported endocrine abnormalities. Impaired AVP secretion in response to osmotic stimuli and reduced thirst might be responsible for such failure.

Adolescent↗

PubMed1988

Binding properties of a mannose-specific lectin from the snowdrop (Galanthus nivalis) bulb.

Carbohydrate binding properties of a new plant lectin (GNA) isolated from snowdrop bulbs were studied using the technique of quantitative precipitation, hapten inhibition, and affinity chromatography on immobilized lectin. Purified GNA precipitated highly branched yeast mannans but did not react with most glucans. Hapten inhibition experiments showed that D-mannose is an inhibitor of GNA-mannan interaction but neither N-acetyl-D-mannosamine nor D-glucose is an inhibitor. Hapten inhibition with various sugars showed that GNA requires the presence of equatorial hydroxyl groups at the C-3 and C-4 positions and an axial group at the C-2 position of the D-pyranose ring. A nonreducing terminal D-mannose residue is necessary for the interaction of oligosaccharides, and oligosaccharides with terminal Man(alpha-1-3)Man units showed the highest inhibitory potency (10-30 times greater than D-mannose) among the manno-oligosaccharides tested. The presence of the hydrophobic p-nitrophenyl aglycone increased the affinity of D-mannose only slightly. Immobilized GNA bound yeast mannan but did not bind glycogen. The behavior of glycoproteins with high mannose type glycan chains depended on the density and the structure of their glycan chains. Glycopeptides which carry Man(alpha 1-3)Man units were retarded on the immobilized GNA column whereas those lacking this unit or with hybrid type glycan chains were not retarded on the column.

Animals↗

PubMed1988

One-step purification of murine IgM and human alpha 2-macroglobulin by affinity chromatography on immobilized snowdrop bulb lectin.

A new mannose-specific plant lectin (GNA) isolated from the snowdrop bulb was immobilized on Sepharose 4B and employed for the purification of certain glycoproteins with high-mannose type glycan chains. Murine IgM bound tightly to this column and was eluted with 0.1 M methyl alpha-D-mannoside whereas bovine and murine IgG were not bound. When a murine hybridoma serum containing IgM monoclonal antibody was applied to this column, highly purified IgM antibody was obtained after elution with methyl alpha-D-mannoside. On the contrary, human IgM was not bound by this column despite reports that it contains high-mannose type glycan chains. alpha 2-Macroglobulin was the sole glycoprotein present in human serum which was bound by the immobilized snowdrop lectin column. It appears that only glycoproteins containing multiple Man(alpha 1,3)Man units are bound to the immobilized lectin.

Animals↗

PubMed1988

Requirement of GTP on somatostatin-induced K+ current in human pituitary tumor cells.

The role of GTP on somatostatin-induced K+ current increase was examined in dissociated human pituitary tumor cells obtained from three acromegalic patients. Pituitary cells in culture were voltage-clamped by using the patch clamp technique in the whole-cell configuration. Somatostatin (100 nM) increased the membrane permeability to K+ ions and inhibited hormone secretion. A current-voltage relation of the somatostatin-induced K+ current showed an inward rectification when the concentration of extracellular K+ ions was increased. The amplitude of the somatostatin-induced K+ current decreased during recording when the patch pipette solution did not contain GTP; addition of 100 microM GTP to the patch pipette solution prevented this reduction. Intracellular application of 100 microM guanosine 5'-[gamma-thio]triphosphate (GTP[gamma S] evoked an inward rectifying K+ conductance in the absence of somatostatin. After the GTP[gamma S]-induced K+ conductance reached a steady level, application of somatostatin did not further increase the K+ conductance. In pertussis toxin-treated cells GTP[gamma S] did not evoke K+ conductance. It was concluded that somatostatin-induced K+ channels were regulated by a GTP-binding protein.

Acromegaly↗

PubMed1988

Two types of calcium channels and hormone release in human pituitary tumor cells.

Voltage-gated Ca2+ channel currents were examined in human growth hormone-producing cells using the whole cell variation of patch electrode voltage clamp. In 20 mM Ba2+, Na+-free medium, the inward current was composed of a fast-inactivating component (transient type) and a steady component (long-lasting type). These two types had different properties. The transient type inactivated with the depolarizing prepulse but the long-lasting type did not. The transient type was activated at more negative potential levels than the long-lasting type. Deactivation kinetics of the transient type were slower than that of the long-lasting type. Nitrendipine inhibited and Bay K 8644 enhanced Ca2+ channel currents, and the effects of these agents were more prominent on the long-lasting type than on the transient type. Hormone release was inhibited by nitrendipine and enhanced by Bay K 8644, indicating involvement of Ca2+ influx through voltage-gated channels in the release process.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1988

Seasonal recurrence of transient hypothyroidism in a patient with autoimmune thyroiditis.

Two postpartum and 7 spontaneous episodes of transient hypothyroidism developed during 5 years of observation in a florist with autoimmune thyroiditis and seasonal allergic rhinitis. The spontaneous episodes recurred twice a year regularly in spring and in autumn, the seasons of her allergic rhinitis. In most of these episodes as well as in the postpartum ones, hypothyroidism was preceded by transient thyrotoxicosis. In addition to the similarity in the clinical course, the changes in antimicrosomal antibody titers in pregnancy-unrelated episodes were almost identical to those in postpartum episodes. Throughout the observation periods, she had supranormal serum total immunoglobulin (Ig) E concentrations and high antigen-specific Ig E levels for various pollen extracts such as cedar and ragweed. However, we failed to demonstrate a correlation between thyroid function and total or any antigen-specific Ig E level. The present findings suggest that the pregnancy-unrelated thyroid dysfunction in our patient developed as a result of silent thyroiditis and through similar immunological mechanisms to those in postpartum thyroiditis. And it is suspected, though unproved, that the seasonal recurrence of pregnancy-unrelated thyroiditis has some causal relation to her allergic disease.

Adult↗