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Biomedical subjects

Y Muranaka

Publications and source records attributed to Y Muranaka.

16 recordsLinked to original sources
PubMed1991

Dissociation of photoreceptor cells from the pineal organ of the lamprey, Lampetra japonica.

Photoreceptor cells, nerve cells and supporting cells were dissociated from the pineal organ of the river lamprey, Lampetra japonica, by the use of 10 U/ml papain solution at 28 degrees C for 20 min, followed by repeated trituration. With the aid of Nomarski interference-contrast optics, photoreceptor cells, nerve cells and supporting cells were readily identified. Electron-microscopic examination revealed that isolated photoreceptor cells display an outer segment endowed with a few lamellar disks and connected to the inner segment (ellipsoid) via a connecting cilium. The structural features of the dissociated photoreceptor and supporting cells strongly resemble the morphology of the respective cellular elements in situ. We succeeded in culturing dissociated cells for time periods up to 48 h when the procedure described in detail was applied.

Animals↗
PubMed1988

Alterations of glomerular basement membrane relevant to haematuria.

To elucidate the morphological basis of glomerular haematuria, morphometric analysis of the glomerular basement membrane (GBM) and lamina densa (LD) was performed on silver impregnated samples for electron microscopy. The cases studied consisted of 3 groups: group A, normal controls, being from donors for kidney transplantation; group B, haematuric; and group C, non-haematuric cases with isolated proteinuria. Qualitative analysis revealed that gap formation, splitting, segmental and diffuse thinning of the GBM occur preferentially in haematuric cases. The morphometry of the GBM and LD yielded increased mean values of the GBM and of LD thickness in groups B and C. The coefficient of variation (CV, SD/mean) for the GBM and LD, however, was the highest in group B among the 3 groups, suggesting the most irregular GBM and LD in group B. In addition, CV was significantly higher in cases with splitting, segmental attenuation and gap of the GBM than cases without. The findings suggest that the irregularity of the GBM rather than its mean thickness is clearly associated with splitting and ultimately with haematuria via the gaps produced.

Adult↗
PubMed1982

Digital processing methods using scanning densitometer and microcomputer for the structural analysis of a scanning electron micrograph.

The fundamental equation of image contrast with practical resolving power is shown taking account of the optical and specimen characteristics. Then, the structural factor which is used to indicate the scattering from the unit of structure to form the periodic object in a scanning electron microscopy can be derived straight-forwardly by digital processing. Based on the Fourier analysis, the reconstruction and subsequent interpretation of structural images such as biological specimens of rat microvilli have been successful. These microvilli must exhibit regularity of a hexagonal lattice consisting of rod-like crystalline arrays. Lattice defects are analysed by means of contrast enhancement, level slicing and histogram plotting techniques. The resolution of SEM can be tested from the granularity distance of coated films by the image sharpening by differentiation and subsequent superimposition of reconstructed images. Furthermore, the structural details in high brightness owing to reducing of the brightness level and filtering the high frequency component have been analysed.

Animals↗
PubMed1982

Uncoated observation and etching of non-conductive materials by ion beam bombardment in scanning electron microscopy.

In a scanning electron microscope, techniques of uncoated observation and subsequent observation of internal and intracellular structures in nonconductive materials removed by ion beam etching have been successfully obtained. An apparatus in which a beam of argon ions is collimated and focused by an electrostatic lens onto an appropriate target and in addition, the specimens are both cooled and rotated during processing to avoid artifacts and thermal damages has been used. Organic and biological specimens can be directly observed without coating of metallic films by pre-bombardment of argon ions. High resolution images of structural details eroded by ion beam etching and coupled with tungsten sputter coating have been clearly observed. The role of angle of incidence of ion beam and accelerating voltage in determining the optimum etching condition without artifacts are experimentally obtained for soft biological specimens as well as hard materials. Step and general views of internal structures in soft biological specimens as well as ceramics and polyvinyl chlorides eroded by cleaning and subsequent etching are revealed without artifacts and thermal damages.

Animals↗