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M Toriyama

Publications and source records attributed to M Toriyama.

At least 19 recordsLinked to original sources
PubMed1992

A novel 24-kDa microtubule-associated protein purified from sea urchin eggs.

Chromatographic fractionation of a crude extract of sea urchin eggs on a hydrophobic column enabled us to find a new 24-kDa microtubule-associated protein (SU-MAP24) that bound tightly to the column and was eluted under alkaline conditions. Biochemical studies using the purified protein showed its direct binding to microtubules reconstituted from tubulin purified from starfish sperm outer fibers. SU-MAP24 promoted tubulin polymerization in a dose-dependent manner. Immunoblotting analysis showed that SU-MAP24 is present in a microtubule protein fraction obtained from a crude extract using taxol, and immunostaining of paraffin-sectioned metaphase eggs showed its localization in the mitotic apparatus. These results show that SU-MAP24 is a newly identified microtubule-associated protein.

Alkaloids↗
PubMed1992

Erythromycin inhibition of lipopolysaccharide-stimulated tumor necrosis factor alpha production by human monocytes in vitro.

The mechanism of clinical effectiveness of low-dose and long-term erythromycin (EM) treatment for diffuse panbronchiolitis, sinobronchial syndrome, and associated otitis media with effusion was investigated by studying the effects of EM on tumor necrosis factor alpha (TNF-alpha) production by cultured human monocytes stimulated with lipopolysaccharide. At concentrations of 0.1 microgram/mL or more, EM inhibited TNF-alpha release from human monocytes stimulated by lipopolysaccharide in a dose-dependent manner. Of the other macrolides tested, roxithromycin, an EM derivative, also showed significant inhibition of TNF-alpha production, whereas josamycin failed to inhibit TNF-alpha release from monocytes. Nonmacrolidic drugs such as minocycline hydrochloride, ofloxacin, or penicillin G had no significant effect on TNF-alpha production. These results suggest that the clinical improvement of chronic respiratory diseases by EM may depend on the suppression of production of inflammatory cytokines such as TNF-alpha.

Anti-Bacterial Agents↗
PubMed1992

[Human monocytes show chemotaxis in response to cholesteatoma debris].

Using a microchamber technique, we tested cholesteatoma debris and certain of its constituents for effects on the migration of human peripheral blood monocytes and polymorphonuclear leukocytes. Cholesteatoma debris induced significant migration of monocytes. When the individual constituents of cholesteatoma debris, i.e., alpha-keratin, cholesterol, lauric acid and lipopolysaccharides, were tested for monocyte chemotaxis, only alpha-keratin induced significant monocyte migration. alpha-keratin extracted from the cholesteatoma debris with 8 M urea also induced migration of monocytes with a bell-shaped dose-response curve, which is frequently encountered with chemoattractants. Therefore, cholesteatoma debris and one of its components, alpha-keratin, are potent chemoattractants for human monocytes. On the other hand, cholesteatoma debris showed no significant chemotactic effect on polymorphonuclear leukocytes. Based on the present and our previous results, cholesteatoma debris acts on monocytes/macrophages as a strong chemotactant, a potent activating (priming) factor, and an inducer of production of tumor necrosis factor, which is a bone-resorbing cytokine. Therefore, we concluded that macrophages induced by cholesteatoma debris may play an important role in the pathogenesis of bone resorption in cholesteatoma otitis.

Chemotaxis, Leukocyte↗
PubMed1991

Two Ca2(+)-binding proteins in the mitotic apparatus of sea urchin eggs.

Two Ca2(+)-binding proteins of sea urchin eggs were purified and partially characterized. They showed Ca2(+)-dependent binding to actin filaments and Ca2(+)-dependent changes of fluorescence intensity which was used to estimate the affinity constant of these proteins to Ca2+ ions. Ca2+ ions did not increase phospholipid binding ability of these proteins. Therefore these proteins are distinguished from the calpactin family. Staining of sections of metaphase eggs embedded in paraffin showed their localization in the mitotic apparatus. Furthermore, staining of whole mount eggs with anti-tubulin and antibodies against these proteins, followed by observations with confocal laser-scanning microscopy showed their co-localization with microtubules more clearly. In vitro co-sedimentation assay of microtubules with these proteins, however, showed no interaction between them. This suggested that some structures surrounding the mitotic apparatus microtubules are responsible for their localization.

Actin Cytoskeleton↗
PubMed1990

The mitotic apparatus-associated 51-kDa protein from sea urchin eggs is a GTP-binding protein and is immunologically related to yeast polypeptide elongation factor 1 alpha.

We investigated the biochemical characteristics of the 51-kDa protein that is a major mitotic apparatus-associated basic protein of sea urchin eggs (Toriyama, M., Ohta, K., Endo, S., and Sakai, H. (1988) Cell Motil. Cytoskeleton 9, 117-128). The amino acid composition of the 51-kDa protein was apparently different from those of tubulin, actin, histones, and myelin basic protein; yet it was similar to those of polypeptide elongation factors 1 alpha (EF-1 alpha). In addition, antibody to EF-1 alpha from yeast cross-reacted with the 51-kDa protein. [3H] GTP binding activity was detected in the phosphocellulose-purified fraction (PC fraction) which predominantly contained the 51-kDa protein and was shown to be specific to GTP, GDP, guanylyl imidodiphosphate, and ITP. Photo-affinity labeling using [alpha-32P]8-azidoguanosine triphosphate (8-azido-GTP) demonstrated that a 51-kDa polypeptide in the PC fraction specifically bound 8-azido-GTP. This GTP-binding polypeptide was bound to a GTP affinity column, could be eluted by the addition of GTP, and was immunoreactive with anti-51-kDa protein antibodies. When the PC fraction was applied to a gel filtration chromatography column, GTP binding activity was completely coeluted with the 51-kDa protein. Furthermore, the PC fraction and the gel filtration-purified fraction had EF-1 alpha activity: [14C]Phe-tRNA transferring activity to ribosomes in the presence of poly(U) and ribosome-dependent GTPase activity. The results indicate that the mitotic apparatus-associated 51-kDa protein is a GTP-binding protein and suggest that it is structurally and functionally related to yeast EF-1 alpha.

Affinity Labels↗
PubMed1989

Purification and characterization of a Ca2+-dependent actin filament severing protein from bovine adrenal medulla.

We describe the purification of an actin regulatory protein from bovine adrenal medulla. This protein caused a dose-dependent decrease of the specific viscosity of actin solution within 30 s of its addition in a Ca2+-sensitive way. Sedimentation assays and the observation by electron microscopy showed that this effect was ascribable to the fragmentation of actin filaments. This protein apparently promoted nucleation of actin polymerization and increased the critical concentration of actin for polymerization nearly 5-fold, suggesting its binding to the barbed end of actin filaments. The inhibitory effect of this protein on the elongation of actin from the barbed end of the myosin subfragment S1-labeled actin seeds confirmed this suggestion. These properties are similar to those of gelsolin. However, the physicochemical properties of this protein having a single polypeptide chain with a molecular weight of 74,000, a Stokes radius of 3.9 nm, a sedimentation coefficient (s0(20),w) of 4.5 S, and an immunological characterization showed that this protein is different from gelsolin.

Actin Cytoskeleton↗
PubMed1989

Tropomyosin in the sea urchin egg cortex.

Tropomyosin was purified from the Triton-treated cortex fraction of fertilized sea urchin egg. Egg tropomyosin showed characteristics typical of nonmuscle tropomyosins such as low molecular mass, short periodicity of Mg2+-paracrystals, low lysine/arginine ratio, high Mg2+ requirement in binding to F-actin, in addition to the properties of all tropomyosins, namely, stability to high temperature, anomalous migration of SDS/urea gel, dissociation from F-actin under high ionic conditions and very acidic isoelectric point. Co-sedimentation assay of egg tropomyosin with actin in the presence of the previously purified high-molecular-mass actin binding protein (260-kDa protein) showed that these two proteins bind to actin filaments in a non-competitive manner. This suggested that both the proteins play a cooperative role in the formation of actin-filament-based cytoskeletal structure in the cortex.

Actins↗
PubMed1989

Human leukocyte antigen in childhood unilateral deafness.

Human leukocyte antigen frequencies were examined in 40 Japanese patients with severe unilateral sensorineural hearing loss found in childhood. Human leukocyte antigen-Bw54 was significantly increased in frequency. No statistically significant deviation in the Bw54 frequency was observed among several possible subgroups studied. Although this group of patients may have various causes, and underlying mechanism is still unclear, this preliminary study suggests that childhood unilateral deafness may be associated with a genetically determined factor(s).

Child↗
PubMed1989

Gene amplification and overexpression of EGF receptor in squamous cell carcinomas of the head and neck.

Tumours of the head and neck were examined for gene amplification and expression of the epidermal growth factor (EGF) receptor by Southern blot and Western blot analyses. The EGF receptor gene was found to be amplified in four (19%) of 21 squamous cell carcinomas. The EGF receptor was overexpressed in eight (53%) of 15 squamous cell carcinomas examined, including all four tumours showing gene amplification. No amplification or overexpression of the EGF receptor gene was detected in any of nine malignant or eight benign tumours of other types of the head and neck. The tumours showing amplification and/or overexpression of the EGF receptor gene (8/15) were all identified histologically as well differentiated squamous cell carcinomas, whereas none of the histologically less differentiated squamous cell carcinomas (0/9) showed amplification and/or overexpression of the EGF receptor gene. Within our sample set, no correlation was evident between amplification and/or overexpression and the clinical stage or tumour site. Our results support the possible involvement of gene amplification and overexpression of the EGF receptor in a subclass of squamous cell carcinomas of the head and neck.

Adult↗
PubMed1989

A comparative study of the distribution of fluorescently labeled calmodulin and tubulin in the meiotic apparatus of the mouse oocyte.

The localizations of tubulin and calmodulin were investigated in the mouse oocyte during the second meiosis by fluorescently labeling and microinjecting these proteins prepared from porcine brain tissue. When injected, both tubulin and calmodulin were quickly incorporated into the preformed meiotic apparatus of the oocyte at metaphase. The localization of labeled tubulin was coincident with that of birefringence. However, the localization of labeled calmodulin was somewhat different: the fluorescence of calmodulin was intense in the polar regions of the spindle. After the chromosomes began to move, followed by parthenogenetic activation upon microinjection of a calcium buffer, these two fluorescent proteins, localized in the meiotic apparatus, moved to the interzonal region of the spindle during anaphase. At late anaphase and throughout telophase, calmodulin was excluded from the mid-bodylike structures in the interzonal region, whereas tubulin did accumulate in these structures.

Animals↗
PubMed1988

51-kd protein, a component of microtubule-organizing granules in the mitotic apparatus involved in aster formation in vitro.

Mitotic apparatuses (MAs) isolated from sea urchin metaphase eggs were chilled on ice to depolymerize microtubules, homogenized, and incubated with tubulin. This caused formation of many small asters with microtubules focusing on granules which were probably fragments of the centrosome. The aster-forming protein components of the granules in the homogenized MAs were solubilized in 0.5 M KCl containing 50% glycerol. After dialysis against low-ionic-strength buffer solution, proteins congregated to form granular assembly capable of initiating aster formation. Phosphocellulose column chromatography enabled the separation of the aster-forming protein fraction which contained a 51,000 molecular weight protein (51-kd protein) as a major component. The protein fraction possessing the aster-forming activity was also prepared from methaphase whole egg homogenate, and the elution profile of the 51-kd protein on phosphocellulose column also coincided with that of the aster-forming activity. The granular assembly reconstituted from the phosphocellulose fraction formed asters whose microtubules show the same growth rate and length distribution as those of asters reconstructed from the granules in the homogenized MAs. Anti-51-kd protein antibody that was raised in rabbit and affinity-purified stained the center of asters which were reconstructed either from the granules in the homogenized MAs or from the granular assembly reconstituted from the phosphocellulose fraction. These results suggest that the 51-kd protein is a component in the aster-forming activity of the centrosomal component in vitro.

Animals↗
PubMed1988

Experimental mumps labyrinthitis in monkeys (Macaca irus)--immunohistochemical and ultrastructural studies.

Three monkeys (Macaca irus) were inoculated with mumps virus into unilateral cochleas and their inner ear were examined by immunofluorescent microscopy and transmission electronmicroscopy. The temporal bones were removed after survival period of 14 days when serological tests disclosed elevation of anti-mumps antibody titers. Immunofluorescent microscopy revealed that the viral antigen was positive in the stria vascularis. The ultrastructural study revealed that the pathologic changes in the cochleas were marked in the organ of Corti and stria vascularis. The outer hair cells were more susceptible to the infection than the inner hair cells. In the stria vascularis, both marginal and intermediate cells were affected. It was possible to find some of marginal cells in the basal turn shedding a large number of mature virions into the endolymph. These pathologic changes observed in the cochleas of the monkeys were similar to those previously revealed in the guinea pig cochleas and thus were considered as the specific features of acute mumps labyrinthitis.

Animals↗
PubMed1988

Studies on the stability of muroctasin and degradation products built under extreme conditions.

Decomposition of N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys(L18), muroctasin) under extreme conditions was investigated. MDP-Lys(L18) in an aqueous solution was heated under reflux for 4 h to give the decomposition products D-1, D-2, D-3 and D-4. Reaction of MDP-Lys(L18) with 0.1N NaOH at room temperature for 5 h gave D-1, and that with 1 N HCl under reflux for 1 h afforded D-4. MDP-Lys(L18) was found to be stable to light and heat. MDP-Lys(L18) in a powder form was stored at room temperature or at 25 degrees C and 75% relative humidity for 3 days to 18 months. Quantitative analysis, thin-layer chromatography, and tests for appearance and color change, etc., were performed in the stored samples. MDP-Lys(L18) was found to be stable, but hygroscopic.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1987

A histological study of the temporal bones and the nose in Wolf-Hirschhorn syndrome.

We report the histopathological findings of the temporal bones and the nasal and paranasal specimen of a 7-month-old girl diagnosed as having Wolf-Hirschhorn or 4p- syndrome (deletion of the short arm of chromosome 4). This syndrome is characterized by growth retardation, mental retardation, and multiple congenital abnormalities, including craniofacial anomalies and hearing disturbance. These temporal bones displayed malformation of the ossicles, absence of the oval windows, abnormal course of the facial nerve with incomplete bony canal, and depression of the cochlear duct and the saccule. In addition, cholesteatoma, which might be of congenital origin, was present behind the eardrum. The nasal and paranasal specimen showed bilateral complete cleft palate with normal development of paranasal sinuses, nasal septum, and conchae.

Abnormalities, Multiple↗
PubMed1987

Redistribution of fluorescently labeled tubulin in the mitotic apparatus of sand dollar eggs and the effects of taxol.

Fluorescently labeled tubulin was quickly incorporated into the mitotic apparatus when injected into a live sand dollar egg. After a rectangular area (1.6 X 16 microns) of the mitotic spindle was photobleached at metaphase or anaphase by the irradiation of a laser microbeam, redistribution of fluorescence was almost complete within 30 sec. The photobleached area did not change in shape during the redistribution. During the period of redistribution, the bleached area moved slightly toward the near pole at metaphase and anaphase (means: 1.6 and 1.8 micron/min, respectively). These results indicate that redistribution was not due to the exchange of tubulin subunits only at the ends of microtubules but to their rapid exchange at sites along the microtubules in the bleached region. Furthermore, treadmilling of tubulin molecules along with the spindle microtubules possibly occurred at the rate of 1.6 micron/min at metaphase. Birefringence of the mitotic apparatus increased with a large increase in both the number and length of astral rays shortly after taxol was injected. However, the microtubules did not all seem to elongate at the same rate but appeared to become equalized in length. Chromosome movement stopped within 60 sec after the injection. Centrospheres became large and the labeled tubulin already incorporated into the centrospheres was excluded from the enlarged centrospheres. Shortly after the labeled tubulin was injected following the injection of taxol, it accumulated in the peripheral region of the centrospheres, suggesting that microtubules first assembled at this region. Fluorescently labeled tubulin in the mitotic apparatus in the egg after injection of taxol was redistributed much more slowly after photobleaching than in uninjected eggs.

Alkaloids↗