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Biomedical subjects

Y Kokubo

Publications and source records attributed to Y Kokubo.

70 records · Page 4Linked to original sources
PubMed1982

Digital image processing: a path to better pictures.

Digital image processing can be used to provide enhanced performance in scanning electron column instruments. Improved visualization, reduced specimen damage, and quantization can be achieved. The system described here provides hardware for digitization and storage of multiple images simultaneously, and multimode scan generation. System software provides easy scan control, image digitization, automatic prescale adjust on acquisition, grey scale histogram generation, grey scale compression or expansion, image filtering, smoothing, and random color assignment to grey levels. Image digitization and processing was done using the EG&G ORTEC Image Master Microanalyzer in conjunction with a JEOL 100CX TEMSCAN and a JEOL JSM 35. Examples of image processing of bright and dark field STEM images of biological specimens are shown. An example of X-ray image processing using a two-dimensional filter function to reduce image noise is also shown.

Computers↗
PubMed1982

Digital image processing: a path to better pictures.

Digital image processing has been used for over a decade to provide startling improvements in the quality of photographs from deep space, satellites and low light level photography. In the last decade considerable work has gone on in major microscope labs in applying these techniques to electron micrographs. Within the last few years a number of factors have come together which allow large scale image processing techniques to be applied at reasonable costs in microscope labs everywhere. The system described here provides hardware for digitization and storage of multiple images simultaneously and multimode scan generation. System software provides easy scan control, image digitization, automatic prescale adjust on acquisition, grey scale histogram generation, grey scale manipulation, image filtering, smoothing, and random color assignment to grey levels.

Animals↗
PubMed1981

Measurement of partial specific thickness (net thickness) of critical-point-dried cultured fibroblast by energy analysis.

The relative specimen thickness obtained with an energy analyser is one of the most important parameters in electron microscopy. It has been made clear that this parameter can be applied not only to inorganic specimens, but also to organic and biological specimens. Moreover, the partial specific thickness of a critical-point-dried cultured fibroblast, that is, a net thickness converted in terms of Epon, was calculated from the relative specimen thickness. The partial specific thickness of each domain of the critical-point-dried cultured fibroblast is: CC 0.05 microns, PE 0.14 microns, ED 0.32 microns and PN 0.54 microns. As a result, it is suggested that 27% of the volume of this specimen consists of biological materials.

Cells, Cultured↗
PubMed1980

Prognosis of four cases of primary middle fossa arachnoid cyst in children.

The treatment and prognosis of 4 cases of primary middle fossa arachnoid cyst in children were analyzed with computed tomography, carotid angiography and Radio isotope cisternography at preoperative and postoperative states. In 2 of 4 cases the cysts reduced their sizes and in the other 2 cases they disappeared after operation. Three surgical methods were performed. The postoperative courses of all cases were good. The disappearance of cysts does not depend on the surgical methods.

Arachnoid↗
PubMed1976

[Characteristics of brain scintigraphy in pediatric age group and its diagnostic value in brain tumors (author's transl)].

The diagnostic value of brain scintigraphy in intracranial diseases has been well recognized. Numerous reports have appeared in the literature concerning its use in adult cases. The reports dealing with pediatrics cases, however, are quite limited in number. The major factors limiting such studies in children may be considered as follows; (1) infratentorial tumors are common in this age group, in which its diagnostic accuracy has been believed to be quite low, (2) problems of exlosing children to radiation and (3) difficulty in keeping children in one position for a considerable length of time. These difficulties were almost overcome by the use of 99m Tc with a very short half life and a gamma camera, resulting in increased application of this procedure to children. The purpose of this report is to analyse and discuss the scintigraphical characteristics in children and evaluate the diagnostic value in brain tumors. The subjects consist of 199 non-tumoral cases and 53 cases of verified brain tumors. Following conclusions were obtained: (1) Aging changes are noted in normal brain scintigrams of children. One of them is related to the mode of visualization of the basal structures in lateral views. The cranial base appears to be flat before the age of 4 years. A triangular process then appears at the cranial base, approaching that of adult over the age of 10 years. Another change is related to appearance of the temporal and occipital muscles over the cranial vault and the posterior fossa. This becomes apparent about the age of 7 years and produces such masking effects as to interfere with diagnosis in this region over the age of 10 years. (2) The choroid plexus are visualized in about 10% of cases. (3) In brain tumor cases, the detecting rate is 93% in gliomas, and 73% in non-gliomatous tumors. It is particularly low in congenital tumors.

Adolescent↗
PubMed1976

[Some characteristic features of RI-cisternography in infancy and childhood (author's transl)].

There are few reports which discussed normal RI-cisternography in infancy and childhood. The cisternograms of the children between 2 months and 13 year-old were classified under a criteria into three groups; 17 normal cases, 135 borderline cases and 77 abnormal cases. The former two groups were compared with each other and characteristic findings of RI-cisternography in infants and children were appreciated clinically. And we attempted to establish normal RI-cisternography. The characteristic findings are: 1) When the images of cisterna magna is dilated, it can not be concluded directly that the abnormality of posterior fossa are suspected. 2) The bulk flow of CSF in infancy and childhood flows faster in intracranial subarachnoid space as well as intraspinal than the flow of adults. 3) Early ventricular reflux seems to be not valuable clinically. But we would like to emphasize that the incidence of these findings are variable as children grow older. The mechanism of this phenomenon needs further investigation.

Adolescent↗
PubMedDate not supplied

Ligamentum flavum hematoma in the thoracic spine.

We report a case of a hematoma of ligamentum flavum at T11-12 in a 66-year-old man who presented with progressive weakness of the right foot and numbness of both legs. Past history was negative and no precipitating episode of lower back sprain or trauma. The resected T11 and T12 laminas showed old hematoma with degenerative changes in the ligamentum flavum. Hematoma occurring in the thoracic spine has never been reported previously.

Aged↗
PubMedDate not supplied

Pathogenesis of calcium crystal deposition in the ligamentum flavum correlates with lumbar spinal canal stenosis.

OBJECTIVE: To investigate the histological and immunohistochemical properties of degenerative changes and calcium crystal deposition in the lumbar ligamentum favum. METHODS: We examined the ligamentum flavum harvested from 119 surgical cases with symptomatic lumbar spinal stenosis. Sections of the ligament were examined by scanning electron microscopy (SEM), energy dispersive X-ray micro-analysis, and were immunostained for S-100 protein, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and CD34. The results were compared with those of ligament tissue harvested from 10 cases of lumbar disc herniation. RESULT: The elastic fibres of the ligamentum favum showed regular, or sometimes irregular, and fragmented fibre bundles. Large areas of fibrosis with reduced elastic component and increased collagenous tissue were frequently seen in the degenerated ligaments. Calcium crystal deposits were observed in these fibrous ligaments, associated with many hypertrophic chondrocytes, and with small blood vessel formation. These chondrocytes stained positively for S-100 protein, VEGF and bFGF Calcium pyrophosphate dihydrate crystals were identified in the calcium deposit area. CONCLUSION: We believe that rupture of elastic fibre bundles is the first change to occur in degeneration of the ligamentum favum. Calcium crystal deposition was seen within these fibrous and chondrometaplastic areas. Hypertrophic chondrocytes regulate crystal formation and tissue reconstruction by secreting cytokines.

Adult↗