Search PubMed⌕ Search

Biomedical subjects

M Toriyama

Publications and source records attributed to M Toriyama.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1987

Acute bilateral deafness with nephritis: a human temporal bone study.

Temporal bone pathology is described in a 37-year-old man who had acute, bilateral, profound sensorineural hearing loss without improvement 4 months before death. The patient had suffered from low complement nephritis, for which he had received prednisolone therapy. Autopsy revealed malignant lymphoma with non-Hodgkin's type, membranous proliferative glomerulonephritis and necrotizing vasculitis of middle and small arteries. In the temporal bone study, pathological changes were limited to the cochlear region. The vestibular structure showed no detectable pathological changes. The changes included total absence of the organ of Corti, atrophy and/or disappearance of the stria vascularis in the upper turns, collapse of Reissner's membrane in the middle turn, and new bone formation in the apical turn.

Adult↗
PubMed1985

Virus-like particles in human vestibular ganglion cells.

We found intracytoplasmic aggregates of virus-like particles in human vestibular ganglion cells. These particles were always observed in the peripheral area of the cytoplasm. Morphological characteristics of the cytoplasm are similar to those of other ganglion cells. The inclusion bodies are round and measure about 1.7 micron in maximum diameter. They consist of a porous convoluted dense material and virus-like particles. The overall diameter of 118 randomly selected particles varies from 36 nm to 73 nm, and the mean value is 53 nm. Most of the particles are spherical while a few possess a hexagonal or semicircular profile. The particles exhibit a double external membrane or vesiculated external layer. Most of the particles are empty. There are, however, some particles which show vesicular structures in their content. Although our present data are insufficient to determine these particles as viral, their hexagonal shape and size are similar to true virus. With these data in mind, we suggest that these particles might be a dormant form of virus and may possibly produce infectious disease in the inner ear.

Aged↗
PubMed1985

Distribution of fluorescently labeled tubulin injected into sand dollar eggs from fertilization through cleavage.

Porcine brain tubulin labeled with fluorescein isothiocyanate (FITC) was able to polymerize by itself and co-polymerize with tubulin purified from starfish sperm flagella. When we injected the FITC-labeled tubulin into unfertilized eggs of the sand dollar, Clypeaster japonicus, and the eggs were then fertilized, the labeled tubulin was incorporated into the sperm aster. When injected into fertilized eggs at streak stage, the tubulin was quickly incorporated into each central region of growing asters. It was clearly visualized that the labeled tubulin, upon reaching metaphase, accumulated in the mitotic apparatus and later disappeared over the cytoplasm during interphase. The accumulation of the fluorescence in the mitotic apparatus was observed repeatedly at successive cleavage. After lysis of the fertilized eggs with a microtubule-stabilizing solution, fluorescent fibrous structures around the nucleus and those of the sperm aster and the mitotic apparatus were preserved and coincided with the fibrous structures observed by polarization and differential interference microscopy. We found the FITC-labeled tubulin to be incorporated into the entire mitotic apparatus within 20-30 s when injected into the eggs at metaphase or anaphase. This rapid incorporation of the labeled tubulin into the mitotic apparatus suggests that the equilibrium between mitotic microtubules and tubulin is attained very rapidly in the living eggs. Axonemal tubulin purified from starfish sperm flagella and labeled with FITC was also incorporated into microtubular structures in the same fashion as the FITC-labeled brain tubulin. These results suggest that even FITC-labeled heterogeneous tubulins undergo spatial and stage-specific regulation of assembly-disassembly in the same manner as does sand dollar egg tubulin.

Animals↗
PubMed1984

Aster formation in vitro is nucleated by granules isolated from the mitotic apparatus.

Mitotic apparatuses (MAs) isolated from sea urchin eggs contained clusters of granular material in their centrospheres. After cold treatment and mild agitation, the MA fraction formed asters when combined with tubulin. Many microtubules grew from isolated centrospheres most of which were covered with astral residues. Homogenization of the isolated MA fraction dispersed the centrospheres which broke into fragments or into aggregates of small granules that formed small asters when tubulin was added. Electron microscopy showed that more than ten microtubules were nucleated from a granular aggregate composed of several approximately 90-nm granules. The aster-forming activity was lost with time when the MAs were kept at 0 degree C. Only glycerol stabilized this activity. The aster-forming activity also was heat labile and trypsin sensitive, but it was resistant to RNase treatment. When the dispersed MAs were extracted with a buffer solution of high ionic strength, aster-forming activity was recovered only in the extract; that is, when the extract had been dialyzed against a solution of low ionic strength, the fine granules self assembled and retained their aster-forming ability.

Animals↗