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Biomedical subjects

N Shibata

Publications and source records attributed to N Shibata.

At least 325 records · Page 18Linked to original sources
PubMed1986

[Three cases of giant aneurysm of the distal posterior inferior cerebellar artery].

Posterior inferior cerebellar artery (PICA) aneurysms constitute approximately 3-6% of all intracranial aneurysms. Especially, aneurysms which originate from distal portion of PICA are very rare. We experienced 4 cases of distal PICA aneurysm, 3 cases of which were giant sized. The clinical and radiological features of cases of a giant aneurysm of distal PICA are analyzed in this study. They consisted of 2 male and 1 female, ranging in age from 37 to 66. They had suffered from headache, disturbances of cranial nerves, cerebellar disorders and dementia, caused by subarachnoid hemorrhage and mass effects of aneurysms. Aneurysmal cavity without organization was shown as a large hyperdensity area in enhanced CT scans, but organized cavity was not enhanced. Angiograms showed that two giant aneurysms in our cases originated from the cranial loop of PICA. Vascular abnormalities such as the vertebral artery terminating as PICA in one case and multiple aneurysms in another case were also seen. As for the treatment, in two cases proximal ligation resulting no neurological deficit was performed. In another case, because of complete organization of the aneurysmal cavity and adhesion between the aneurysm and the brain stem, extirpation of the aneurysm could not be done. In one patient who had symptomes of cerebellar disturbance, removal of the thrombus resulted in good recovery.

Adult↗
PubMed1985

Filamin inhibits actomyosin ATPase activity in platelet.

Filamin, an actin cross-linker protein, has been shown to exist in platelet. The role of this protein in the platelet has remained unclear. In this report, we show that filamin inhibits the actin-activated Mg2+ -ATPase activity of platelet myosin. The activation caused by platelet actin is inhibited by 50% at the molar ratio of filamin to actin of 1/50. Platelet tropomyosin, which we showed to enhance the ATPase activity, does not abolish the effect of filamin. The results support the view that filamin stabilizes the actin network in the resting platelet.

Actins↗
PubMed1985

Immunochemical study on the mannans of Candida albicans NIH A-207, NIH B-792, and J-1012 strains prepared by fractional precipitation with cetyltrimethylammonium bromide.

The mannans of Candida albicans NIH A-207 (A strain, serotype A), C. albicans NIH B-792 (B strain, serotype B), and C. albicans J-1012 (J strain, serotype C) prepared by fractional precipitation with cetyltrimethylammonium bromide (Cetavlon) were investigated for their immunochemical properties. Upon treatment with 10 mM HCl at 100 degrees C for 60 min, the mannans of A and B strains each released a mixture of manno-oligosaccharides ranging from hexaose to mannose together with (for each one) an acid-modified mannan, while J-strain mannan released lower oligosaccharides, tetraose to mannose. The acid-modified mannan of B strain did not show antibody-precipitating activity against homologous antiserum, whereas acid-modified A- and J-strain mannans retained most of this activity. The acid-released oligosaccharides were assumed to consist of beta-1,2-linked D-mannopyranosyl residues from the results of specific rotation and proton magnetic resonance studies.

Antigens, Fungal↗
PubMed1985

Promotion of the selective lymphatic delivery of cyclosporin A by lipid-surfactant mixed micelles.

The absorption of an immunosuppressive drug, cyclosporin A (CsA), with the aid of lipid-surfactant mixed micelles from the rat gastrointestinal (GI) tract and lymphatic delivery were studied. The administration of CsA in oily solution, sesame oil or linolic acid, into the rat duodenum indicated a small amount of CsA both in the plasma and lymph for about 6 h. The administration of CsA in the mixed micellar solution composing of linolic acid and HCO-60, polyoxyethylated (60 mol) hydrogenated castor oil, accelerated the absorption of CsA from the GI tract, and CsA was delivered into the lymphatics with an extremely high selectivity.

Animals↗
PubMed1985

Macrophages in glomerular injury. I. The kinetics of macrophages in accelerated Masugi nephritis in the rat.

To evaluate the role of macrophages in glomerulonephritis, the relationship between the existence of macrophages and proteinuria in the long course of glomerulonephritis was studied in accelerated Masugi nephritis in the rat. Non-specific esterase staining was used as a marker of macrophages and the kinetics of glomerular macrophages was analysed by an image processor. Macrophages became detectable 48 hours after nephrotoxic serum injection and their accumulation reached a maximum level at 5 days. At 1 month, they had clearly decreased. At 3 months, however, many macrophages were found within the capsular drop-like lesions and crescents. Urinary protein excretion took roughly the same time course as the number of macrophages for 2 weeks. However, at 1 month, whereas macrophages had decreased, the proteinuria kept a persistently high level. At 3 months it showed a tendency to decrease. The correlation between the rate of appearance of macrophages and the urinary protein excretion assessed in 20 cases exhibited no significance. In addition, discrepancy in their time course was evident at 1 month. Although macrophages may happen to contribute to the tissue injury resulting in proteinuria in the early phase of nephrotoxic serum nephritis, factors other than macrophages should be considered in the subsequent duration of proteinuria in this model.

Animals↗
PubMed1985

High performance liquid chromatographic determination of cyclosporin A in body fluids.

A sensitive, specific and reproducible high performance liquid chromatographic assay method for the determination of a new immunosuppressant, cyclosporin A (CsA), in the biological samples such as human blood, rat plasma and rat lymph has been developed. CsA was extracted with diethyl ether followed by being cleaned up with liquid-liquid extraction procedure using carbon tetrachloride-methanol system, and was chromatographed on a microparticulate CN column with UV detection at 212 nm. The lower detection limit is 100 ng/ml in human blood (from 1.0 ml) and 500 ng/ml in the rat plasma or lymph (from 0.2 ml). This method is sensitive enough for monitoring CsA concentrations in the renal transplant patients in the therapeutic dose range, and is also applicable to the determination of CsA in the rat plasma and lymph samples for the purpose of pharmacokinetic evaluation of several CsA dosage forms in the rats.

Animals↗
PubMed1984

Enhancement of actomyosin ATPase activity by tropomyosin. Recombination of myosin and tropomyosin between muscles and platelet.

In skeletal muscle, the physiological role of tropomyosin has been assumed to be the 'blocking' of the actin-myosin interaction. In smooth muscle and platelet, however, tropomyosin was shown to 'enhance' the interaction. To investigate the reason for this apparent contradiction, we carried out recombination experiments using reconstituted actomyosins and different tropomyosins. Tropomyosins from skeletal muscle, arterial smooth muscle and platelet were recombined with skeletal, arterial and platelet myosins. The effects of tropomyosins on the actin-activated ATPase activities of myosins were then examined. The results are as follows. (i) Although tropomyosins from artery and platelet are distinctively different in molecular weight, they are interchangeable in enhancing the ATPase activities of both arterial and platelet actomyosins. The enhancement, however, is reduced by increasing the concentration of Mg X ATP and decreasing the concentration of myosin. (ii) Arterial and platelet tropomyosins are not capable of inhibiting the ATPase activity of skeletal actomyosin. (iii) Skeletal tropomyosin enhances arterial and platelet actomyosin ATPase activities in the same way as arterial and platelet tropomyosins. The results indicate that the major determinant of the effect of tropomyosin on the actomyosin-ATPase activity is the state of actomyosin. We suggest that any tropomyosin enhances the actin-activated ATPase activity of myosin recombined with skeletal actin, under the condition where actin and myosin form a 'rigor' (tight) complex.

Actomyosin↗
PubMed1984

Reorganization of contractile elements in the platelet during clot retraction.

Electron microscopic studies have been carried out on human platelets in the clot retraction. In the early stage of clot formation, platelets send out filopodia, in which thin filaments run longitudinally. The thin filaments are often observed to attach to the cell membrane where fibrin strands bind from the extracellular surface. In the later stage of clot formation, thick filaments become observable, mainly in the cell body of the platelets. These thick filaments are arranged to form an ordered array, and thin filaments run parallel to them. The thin filaments often attach to the end of the thick filaments. However, thin filaments are not seen between the arrays of thick filaments. Similar structures are also observed in the cytoskeleton of the contracted platelet. These filaments closely resemble the purified myosin aggregates formed under low ionic strength. Thus, during clot retraction, both actin and myosin in platelets are reorganized into thin and thick filaments, respectively.

Blood Platelets↗
PubMed1984

Immunochemical properties of mannan-protein complex isolated from viable cells of Saccharomyces cerevisiae 4484-24D-1 mutant strain by the action of zymolyase.

Viable cells of Saccharomyces cerevisiae 4484-24D-1 mutant strain were treated with an Arthrobacter sp. beta-1,3-glucanase, Zymolyase-60,000, in the presence of a serine protease inhibitor, phenylmethylsulfonyl fluoride. Fractionation of the solubilized materials with Cetavlon (cetyltrimethylammonium bromide) yielded a purified mannan-protein complex, which had a molecular weight of ca. 150,000, approximately three times higher than that of the mannan isolated from the same cells by the hot-water extraction method at 135 C. The amino acid composition of the mannan-protein complex was found to be very similar to that of the mannan-protein complexes of S. cerevisiae X2180-1A wild and S. cerevisiae X2180-1A-5 mutant strains, indicating the presence of large amounts of serine and threonine. It was unexpected that the antibody-precipitating activity of this complex against the homologous anti-whole cell serum was about twice as great as that of the mannan isolated by hot-water extraction. Treatment of this complex with 100 mM NaOH, hot water at 135 C, and pronase, respectively, gave degradation products having the same molecular weight and antibody-precipitating activity as those of the hot-water extracted mannan, allowing the assumption that the protein moiety participated in a large part of this activity.

Amino Acids↗
PubMed1984

[The outcome of acute subdural hematoma].

Thirty-five cases of acute subdural hematoma (ASDH) were reviewed and divided into two groups of A and B according to the outcome. The findings of computed tomography (CT) and the time interval between head trauma and surgical intervention were investigated to know the factors that influence the prognosis in ASDH. Group A, 18 patients, had a poor outcome. Fifteen patients out of 18 had the removal of hematoma and decompression craniectomy with 10 deaths, 4 vegetative states and 1 severe disability. Three patients died without surgery. Group B, 17 patients, were treated surgically in the same way as in group A and all patients had a good recovery with 14 making a full recovery and 3 with a moderate disability. Surgical mortality was 31.3% and overall mortality was 37.1%. The features of the CT findings in 18 patients of group A were as follows. Eleven patients had midline shift of more than 15 mm, 9 had subdural high density area of more than 15 mm and 12 patients had bilateral collapse of the lateral ventricles. The characteristic finding of CT recognized in all patients of group A was disappearance of the ambient cistern. On the contrary, in 17 patients of group B the displacement of the intracranial structure was not so severe as in group A. The midline shift of 14 patients was less than 7.5 mm, the width of subdural high density area of 15 patients was less than 7.5 mm and the ambient cistern was recognized in 12 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1983

Isolation of mannan-protein complexes from viable cells of Saccharomyces cerevisiae X2180-1A wild type and Saccharomyces cerevisiae X2180-1 A-5 mutant strains by the action of Zymolyase-60,000.

The viable whole cells of Saccharomyces cerevisiae X2180-1A wild type and its mannan mutant strain S. cerevisiae X2180-1A-5, were treated with an Arthrobacter sp. beta-1,3-glucanase in the presence of a serine protease inhibitor, phenyl-methylsulfonyl fluoride. Fractionation of the solubilized materials of each strain with Cetavlon (cetyltrimethylammonium bromide) yielded one mannan-protein complex. Molecular weights of these complexes were almost the same as that of the mannoprotein of the mutant strain prepared by Nakajima and Ballou, which had a molecular weight of 133,000 and were approximately three times larger than those of the mannans isolated from the same cells by hot-water extraction. Each mannan-protein complex contained up to 2% glucose residue, which was not removed by specific precipitation with anti-mannan sera or by affinity chromatography on a column of concanavalin A-Sepharose. Treatment of these complexes with alkaline NaBH4 produced peptide-free mannan containing small amounts of glucose nearly identical to those of the parent complexes. The above findings provide evidence that the glucose residues exist in a covalently linked form to the mannan moiety. Fractionation of the mannan-protein complex of the S. cerevisiae wild-type strain by DEAE-Sephadex chromatography yielded five subfractions of different phosphate content, indicating that these highly intact mannan-protein complexes were of heterogeneous material consisting of many molecular species of different phosphate content.

Amino Acids↗