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Biomedical subjects

K Kanaya

Publications and source records attributed to K Kanaya.

At least 19 recordsLinked to original sources
PubMed1991

GABA distribution in the central vestibular system after retroauricular galvanic stimulation. An immunohistochemical study.

The changes of the neurotransmitter (GABA) distribution in the brain stem of rats by retroauricular galvanic stimulation were investigated using the immunohistochemical method. In the lateral vestibular nucleus GABA-like immunoreactivity was more intensive on the side ipsilateral to the anodal stimulation than on the other side. It is concluded that retroauricular galvanic stimulation causes some changes in the inhibitory activity of the lateral vestibulo-spinal tract and of the spinal motor neuron.

Animals↗
PubMed1991

Compensatory process of vestibular neuronitis. From findings of combined galvanic test and caloric test.

The compensatory process of vestibular neuronitis in 7 patients was followed up and evaluated using the Combined Galvanic Test (CGT) and other neuro-otological data. CGT is the simultaneous recording of both galvanic eye movement (GEM) and galvanic body sway (GBS), and has proved to be reliable in the diagnosis of retrolabyrinthine disorders. The results were as follows: The subjective symptoms remained in 3 cases from 1 month to 1 year. The recovery of the GBS response was seen earlier than that of both GEM and caloric responses. The recovery of GEM and caloric responses was observed at almost the same time. We observed the favorable recovery process of caloric response and GEM response in some cases which had recovery of GBS response within 4 weeks and suggest that the system of GBS response is different from that of GEM and caloric response. However, the systems of the latter two may be the same. We assume that the recovery of GBS response is earlier than that of GEM and caloric responses because the otolithic system recovers more easily than the semicircular canal system. The CGT and caloric test were reliable in examining the compensatory process of vestibular neuronitis.

Adult↗
PubMed1991

[Decreased cerebral blood flow in remote areas in deep-seated cerebrovascular lesions].

Recent positron or single photon emission computed tomographic studies have demonstrated that the impairment of regional hemodynamics or metabolism in cerebrovascular disease is not limited to the focal lesion, but also involves more remote areas. The present study evaluated cerebral blood flow in areas remote from the primary lesion in patients with subcortical cerebrovascular disease, and assessed correlations with the clinical features. Twenty patients aged 61-89 (mean, 74.7 +/- 6.7 years) were divided into the L group (lacunar infarction in deep penetrating arterial territory, n = 7), the NL group (non-lacunar subcortical infarction caused by main trunk occlusion or severe stenosis, n = 6), and the H group (putaminal or thalamic hemorrhage, n = 7). Ipsilateral cortical and contralateral cerebellar blood flow were assessed using single photon emission computed tomography with 123I-IMP. Although only some patients of the L group showed a mild reduction of ipsilateral cortical blood flow, most of the patients in the NL and H groups showed a moderate or severe flow reduction. The cortical blood flow reduction was suggested to be caused by several mechanisms, including brain edema, a decreased perfusion pressure associated with disease of large arteries, partial cortical neuronal damage, and deactivation. The degree of the flow reduction was considered to depend on the relative contribution of each of these factors. Contralateral cerebellar blood flow reduction, i.e., crossed cerebellar diaschisis, was observed more frequently and prominently in the NL and H groups than in the L group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Localized amyloidosis of larynx. A case report and immunohistochemical study].

A case of the localized laryngeal amyloidosis was reported. The patient was a 51-year-old female who complained of hoarseness for about a year. Pathological study on the biopsy specimen taken from both the subglottic area under laryngeal microsurgery showed the deposit of amyloid. Laryngeal microsurgery showed the deposit of amyloid at bilateral subglottic area. Electron microscopic study disclosed a typical amyloid fibrillar structure. Amyloid protein, in this case, was confirmed as protein A lambda appeared through the potassium permanganate treatment and immunoperoxidase technique (ABC method).

Amyloid↗
PubMed1990

Transmission electron microscopic x-ray quantitative analysis of human dentin at 200 kV accelerating voltage.

Qualitative and quantitative x-ray energy dispersive spectroscopy is now used successfully to analyze many features and processes in inorganic samples. When applied to inorganic samples, however, the results are often less satisfactory due to problems of preparation of organic samples, difficulty of measuring x-rays from organic samples, damage of the sample by the electron beam, and other practical problems. In the present study we used a high voltage transmission electron microscope equipped with an energy dispersive x-ray spectrometer to examine accurate quantitative standardless analysis of thin sections of an organic sample, human dentin. Based on our experiments we found the important parameters for quantitative analysis were sample thickness and appropriate choice of model sample. Further, we show that the method of Cliff and Lorimer can be used with biological samples at 200 kV, and we show that quantitative analysis of human dentin can be carried out at 200 kV. Finally, we show that areas of human dentin can be differentiated by their morphological characteristics and x-ray analyses obtained in the transmission electron microscope.

Child↗
PubMed1989

Serial section reconstruction using a computer graphics system: applications to intracellular structures in yeast cells and to the periodontal structure of dogs' teeth.

A computer graphics system for reconstruction from serial section micrographs was applied to intracellular details of a yeast target cell (Saccharomyces cerevisiae cell) induced by the alpha factor mating pheromone and was also applied to a periodontal structure of a dog tooth moved orthodontically. In the former, intracellular organelles and a distribution of vesicles could be clearly observed through the cell membrane using the transparent display method in which the smoothing of the reconstructed outer cell membrane surface by computer processing was applied to the transparent display. In the latter case, by cutting through a reconstructed dog tooth and its periodontal tissues, labiolingual and mesiodistal cut surfaces of the tooth and of adjacent alveolar bone could be observed with fine details (232 sections were used).

Animals↗
PubMed1989

Application of ion-beam etching techniques to the fine structure of biological specimens as examined with a field emission SEM at low voltage.

The term "etching," in electron microscopy, refers to the removal of specimen surface layers and includes chemical, electrolytic, and ion-beam methods. The ion-beam etching process is used to remove layers of a target material by bombarding it with ionized gas molecules. Recently, the method has been applied to the field of biological specimens; however, the practical procedures for such organic materials have not been developed. In the present study, we used an apparatus in which a beam of argon ions is collimated and focused by electrostatic lenses onto an appropriate target. We demonstrated the optimum conditions to observe biological specimens that were treated with osmium tetroxide and tannic acid. The specimens were examined uncoated at low accelerating voltage using a field emission scanning electron microscope. According to our experiments, when a biological specimen was observed under high-resolution conditions at over 50,000x magnification, the optimum condition of ion-beam etching consisted of an accelerating volage of E = 1 keV and an ion-beam dose of It = 360-400 microA.min, depending on parts of the specimens. In order to decrease overetching, we had to choose factors such as E = 1-2 keV and It = 500 microA.min.

Animals↗
PubMed1989

Three-dimensional analysis of morphogenesis induced by mating pheromone alpha factor in Saccharomyces cerevisiae.

Ultrastructural analyses of cytoplasmic changes in Saccharomyces cerevisiae X2180-1A (MATa) that had been treated with alpha factor were performed by using the freeze-substitution fixation method. After alpha factor treatment, cells exhibited a pointed projection, which is a unique pattern of oriented cell surface growth. The relationship between projection formation and intracellular organelles was examined using serial thin sections and computer-aided three-dimensional reconstructions. Using these analyses membrane vesicles and other organelles were detected, and studies on their dynamic structural reorganization became feasible. Production of membrane vesicles (average 65 nm in diameter) was induced upon exposure of the cells to alpha factor before projection emergence. The total number of membrane vesicles increased at the early stage and decreased at the late stage of projection formation. Three-dimensional analysis indicated that the vesicles were at first dispersed throughout the cell, then accumulated at the site where the projection formed. Morphological changes and multiplication of the Golgi body were seen during the process of projection formation. Other intracellular organelles (nucleus, vacuole, rough endoplasmic reticulum and mitochondria) were also rearranged, showing a polar organization of the cytoplasm during projection formation.

Mating Factor↗
PubMed1988

Digital image processing of crystalline specimens examined by electron microscopy.

Crystalline specimens imaged in the electron microscope are analysed using digital processing. Some principles of structural analysis using the method of Fourier decomposition are discussed. Complementary techniques, such as enhancement by gradient and Laplacian operators, have been found useful in analysing electron micrographs. The application of these techniques to some problems in Materials Science and Biology are reviewed. By selecting and phase-correcting spots in the computed diffraction pattern, it was possible to localize atoms, molecules, and their defective arrangement in evaporated gold, sputter-deposited tungsten films, and single crystals of cadmium selenide. Digital processing based on the theory of helical diffraction was used to explore the three-dimensional arrangement of molecules in cellular components of alveolar soft part sarcoma, Hirano bodies, and neurofibrillar tangles in the human brain.

Actins↗
PubMed1988

Ultrastructural analysis of neurofibrillary tangles of Alzheimer's disease using computerized digital processing.

The ultrastructure of neurofibrillary tangles of Alzheimer's disease was analyzed by computerized digital processing of electron micrographs. Processing of the electron micrographs consists of four steps: digitizing the electron micrograph, Fourier transformation, noise filtering and inverse Fourier transformation and Laplacian operation. In the present study, we have confirmed that neurofibrillary tangles are composed of a pair of helical filaments (PHF), which appear characteristically as an unbranched rigid structure. The periodicity of PHF is 78 nm on the diffractogram. The dimensions of PHF obtained by our analysis, although basically similar to those described earlier by other investigators using conventional techniques, more precisely defines its structural conformation. We have also demonstrated that the spatial relationship of two filaments appears symmetrical after two-way tilting of the specimen about the axis of rotation. Our observations emphasize the importance of digital image processing as an effective tool for structural analytical research in biology and medicine.

Actin Cytoskeleton↗
PubMed1988

Three-dimensional reconstruction from serial section images by computer graphics.

A method is described which allows a three-dimensional object to be reconstructed from micrographs of serial sections using computer graphic techniques. The reconstructed object, which can be rotated three-dimensionally, is displayed on a color CRT and the surface of the object is shaded in order that it can be observed to provide an illusion of a three-dimensional structure. Using biological samples, some useful representation methods are demonstrated, which are a transparent display, smoothing of a reconstructed surface, cuts through a reconstructed model and a three-dimensional distribution representation of particles, and so forth. Furthermore, an example measuring the volume and surface area of reconstructed objects is shown.

Animals↗
PubMed1986

The structure analysis of Hirano bodies by digital processing on electron micrographs.

To clarify the structure of Hirano bodies, electron micrographs of Hirano bodies taken at various tilting angles have been studied by digital image analysis. On the electron micrographs, the beaded filaments of Hirano bodies were turned into a pattern of lattice-like arrays by changing the tilting angles. Based on computer-processed diffraction patterns and filtered images, it is proposed that the filaments of Hirano bodies are helical strands with a pitch of 185 A. A model for the helical strand drawn by microcomputer at various angles of rotation is in accordance with the filtered images of the tilted filaments. Computer simulation also reveals that the helical strands appear to be lattice-like when they are arranged in parallel.

Dementia↗
PubMed1985

The morphology of L-fucose, D-mannose specific lectin (SFL 100-2) produced by Streptomyces No. 100-2.

The morphology of an L-fucose specific lectin, SEL 100-2, from a Streptomyces sp. was studied. Electron microscopic observation showed that purified SFL 100-2 preparation consisted of particles homogeneous in size. The diameter was 25 nm. The digitized images of these particles had 2-fold rotation symmetry. The sedimentation coefficient (s020,w) was determined to be 20.6S. The particle weight and the Stokes radius were calculated to be 8.0 X 10(5) daltons and 94 A, respectively, by three independent methods, i.e., gel filtration, sedimentation equilibrium and velocity measurements. The frictional ratio (f/fmin) was estimated to be 1.53. These values are quite similar to those of human alpha 2-macroglobulin. 125I-Labeled peptide mapping indicated that these particles were built up of about twelve identical subunits (Mr = 68,000). The size of SFL 100-2 in culture broth was found to be the same as that of the particles in the purified preparations. The shape and other properties of SFL 100-2 are discussed and compared with those of the tail of lambda phage and type 1 pili of Escherichia coli, whose amino acid compositions were quite similar to that of SFL 100-2 and also those of L-fucose specific plant lectins.

Autoradiography↗
PubMed1976

High resolution shadowing for electron microscopy by sputter deposition.

The sputtering process by an ion beam well collimated and highly accelerated provides a valuable means of high resolution shadowing, replication of a fine object by a combination of pre-shadowing and deposition as well as a preparation of supporting films. High resolution shadowing and films with grains smaller than 1 nm can be obtained by argon ion-sputtering targets of tungsten and tungsten/tantalum alloy. The resolution of carbon replicas pre-shadowed with tungsten/tantalum is determined from the radius of curvature of replicated magnesium oxide crystal corners.

Alloys↗
PubMed1975

The pH jump study of enzyme proteins. I. Liquefying alpha-amylase from Bacillus subtilis.

Rapid conformational changes due to pH jump were studied kinetically at 25 degrees mainly by the stopped-flow method using liquefying alpha-amylase from Bacillus subtilis [EC 3.2.1-.1, liquefying]. First, the conformational change due to a pH jump produced by mixing with alkali was monitored as a function of time at 245 nm through the ionization of phenolic hydroxyl groups of tyrosine residues which were originally buried and finally become exposed due to the pH jump. Three distinct phases of conformational change were clearly recognized by this method by varying the final pH values. Each phase involved the exposure of an essentially definite number of tyrosine residues, whose rate constant was crucially dependent on pH. Second, these phases of conformational change were subjected to examination in terms of the optical rotation change at 411 nm and the reversibility upon reverse pH jump with respect to conformational reconstitution, as observed through the protonation ofphenolic hydroxyl groups of ionized tyrosine residues and the enzyme activity. The first phase, which occurs above pH 12.5, involves no change in the optical rotation and is reversible as observed by the above two monitoring methods. In contrast, the other two phases, which are observed above pH 12.7, are accompanied by an optical rotation change and no appreciable reversibility was detected by these methods.

Amylases↗