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Biomedical subjects

T Ogata

Publications and source records attributed to T Ogata.

At least 361 records · Page 20Linked to original sources
PubMed1990

[Neurofibroma originated from the intrathoracic vagal nerve in a patient with von Recklinghausen's disease--a case report].

A neurofibroma originated from the intrathoracic vagal nerve was presented. A 26-year-old male was found to have an abnormal shadow in the right chest filed on a routine examination. He was complicated with Von Recklinghausen's disease and showed multiple "cafe au lait" spots over his extremities and trunk but no subcutaneous mass. A block resection of the mass was carried for the mediastinal tumor. The tumor was arising from the right intrathoracic vagal nerve which located just below the origin of recurrent nerve and was measured 3 X 3 X 6 cm. Histological examination of the specimen revealed neurofibroma. His postoperative course was uneventful. A brief review in Japan was made on 22 cases collected from the literature.

Adult↗
PubMed1990

[Three-dimensional change of the occlusal facets in primary dentition before and after the eruption of first permanent molars].

A system to measure the three-dimensional architecture of the occlusal surface was developed to clarify the three-dimensional change of the morphology of occlusal facets that was considered as the trace mark of the chewing function. The three-dimensional measuring and analyzing system of the occlusal surface was composed of two components, the measuring system to obtain the three-dimensional coordinates on the surface contour of the tooth crown and the analyzing system to calculate the minute morphology in the three dimensions. The reproducibility of this system was evaluated with use of the standard block of stainless steel designed for this purpose and was shown to be very accurate. By application of this system, the three-dimensional changes of the occlusal facets on primary canines and primary second molars were investigated on the serial primary dental casts taken before and after the eruption of the first permanent molars from eleven children (seven boys and four girls). The results were as follows: On the primary second molars of the maxilla and mandible, before the eruption of the first permanent molars, the occlusal facets were distributed mainly on the functional cusps. The occlusal facets were found also on the non-functional cusps after the eruption of first permanent molars. As a consequence, the increase in the number of occlusal facets from before to after the eruption of first permanent molars was statistically significant for both maxillary and mandibular primary second molars. In regard to the morphological change in three dimensions, the occlusal facets that were facing mesially or distally before the eruption of first permanent molars changed its direction buccally or lingually and became almost parallel to the datum plane of the mandibular dental arch after the eruption of the first permanent molars. It was also found that the occlusal facets of both jaws in the occlusal relationship were almost parallel to each other. In addition, the amounts of angular change before and after the eruption of first permanent molars were significantly correlated between the maxillary and mandibular occlusal facets. It can be concluded that the coordinating change of the occlusal facets in three dimensions may exist between both jaws during the development of chewing function.

Child↗
PubMed1990

[Brachial plexus injury and fracture of the first rib as complications of median sternotomy].

In 192 patients following median sternotomy during from 1978 to 1988, we studied the incidence, cause, prognosis and correlation of brachial plexus injury and fracture of the first rib as complications of median sternotomy. Four brachial plexus injuries were identified, an incidence of 2.1%, seven first-rib fractures were identified, an incidence of 3.6% and one patient had both complications in this series. Symptoms of this patient were more severe and difficult to improve than those of patients without first-rib fracture. Stretching of the nerve by the displaced first rib, ischemia of the nerve by pressure on it, and direct injury by the fractured rib end are causes of the brachial plexus injury following median sternotomy. It is due to the difference of position of the fracture, the difference of direction and degree of the protrusion of the fractured rib end, whether presence or absence of the brachial plexus injury in patients with first-rib fracture.

Adolescent↗
PubMed1989

Induction of microsomal 1-acylglycerophosphocholine acyltransferase by peroxisome proliferators in rat kidney; co-induction with peroxisomal beta-oxidation.

Induction of microsomal 1-acyl-glycerophosphocholine (GPC) acyltransferase in rat tissues by four peroxisome proliferators, clofibric acid, tiadenol, DEHP and PFOA, was examined. Among the nine tissues examined, kidney, liver and intestinal mucosa responded to the challenges by the peroxisome proliferators to induce the enzyme. The treatment of rats with various dose of clofibric acid, tiadenol, DEHP or PFOA resulted in an induction of kidney microsomal 1-acyl-GPC acyltransferase in a dose-dependent manner. Despite the structural dissimilarity of peroxisome proliferators, the induction of microsomal 1-acyl-GPC acyltransferase was highly correlated with the induction of peroxisomal beta-oxidation. The activity of microsomal 1-acyl-GPC acyltransferase was not affected by changes in hormonal (adrenalectomy, diabetes, hyperthyroidism and hypothyroidism) and nutritional (starvation, starvation-refeeding, fat-free-diet feeding and high-fat-diet feeding) states. The induction of renal microsomal 1-acyl-GPC acyltransferase was seen in mice subsequent to the administration of clofibric acid and tiadenol and in guinea pigs subsequent to the administration of tiadenol. These results may indicate that kidney microsomal 1-acyl-GPC acyltransferase is a highly specific parameter responsive to the challenges by peroxisome proliferators and may suggest that the possibility that the inductions by peroxisome proliferators of microsomal 1-acyl-GPC acyltransferase and peroxisomal beta-oxidation in kidney are co-regulated.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1989

Lung cancer-associated monoclonal antibody 15 that recognizes cell growth-related membrane antigens gp85/45 and its growth-inhibitory effect on human lung cancer cells in vitro.

In order to find lung cancer-specific markers, monoclonal antibody 15 (MAb15) was produced against a variant-type cell of small cell lung carcinoma. Its gp85/45 antigens were demonstrated in 70% of lung cancers, and particularly in the proliferating zone of cancer cell nests, but they are scarcely detected in noncancerous tissues. Immunoelectron microscopy revealed that gp85/45 antigens were expressed alternatively on the cell membrane of living cancer cells according to their biological states. MAb15 added to the culture medium inhibited the proliferation of lung cancer cells, depending on its concentration, but cell death rate did not increase. The growth inhibition by MAb15 was reevaluated by a colonogenic assay. On DNA histogram, MAb15 decreased the number of DNA-synthesizing cells in the S phase with an elevation of the G1 peak, indicating a G1-S boundary block in the cell cycle. gp85/45 detected by this lung cancer-associated monoclonal antibody could be a functional membrane unit, such as a growth factor receptor, which is related to the cell proliferation of lung cancer. The growth inhibition by MAb15 may be caused by the blocking of a growth factor receptor which is specific to lung cancer.

Antibodies, Monoclonal↗
PubMed1989

High resolution scanning electron-microscopic study on the three-dimensional structure of the sarcoplasmic reticulum in the slow (tonic) muscle fibers of the frog, Rana nigromaculata.

The three-dimensional structure of the sarcoplasmic reticulum (SR) in the slow (tonic) fibers of the rectus abdominis muscle of the Japanese meadow frog (Rana nigromaculata nigromaculata Hallowell) was examined by high resolution scanning electron microscopy, after removal of the cytoplasmic matrices by the osmium-DMSO-osmium procedure. The SR forms a repetitive network throughout these fibers. At the level of the Z-line, a slender transverse tubule (T-tubule) runs transversely to the longitudinal axis of the myofibril. Small, spherical or ovoid terminal cisternae couple laterally with the T-tubule at intervals of 0.4-1.0 microns, and form a "terminal cisterna-T-tubule complex" on whose surface tiny indentations are occasionally seen. Each terminal cisterna gives rise to a few sarcotubules that run in various directions, divide frequently and form circular or oval meshes of diverse sizes in front of the A- and I-bands. The sarcotubules usually form small meshes in the middle of the A-band, but occasionally fuse and form a poorly developed H-band (fenestrated) collar.

Animals↗
PubMed1989

Physiological changes during temporary occlusion of the superior vena cava in cynomolgus monkeys.

To evaluate the physiological changes that occur after temporary occlusion of the superior vena cava, we clamped the vena cava for one hour in 6 cynomolgus monkeys, monkeys with a venous system most resembling that of humans. The data from arterial blood gas analysis, ie, pH, arterial oxygen tension, arterial carbon dioxide tension, and HCO3-, were within normal limits during and after occlusion of the superior vena cava. Intracranial pressure was 8.6 +/- 0.8 mm Hg (mean +/- standard error) before occlusion and rose to 22.1 +/- 2.2 mm Hg during clamping. It decreased significantly to 17.7 +/- 1.9 mm Hg just before removal of the clamp and recovered to 8.6 +/- 0.9 mm Hg after the clamp was removed. Regional cerebral blood flow was 45 +/- 9 mL/min/100 g before clamping and decreased to 37 +/- 3 mL/min/100 g during clamping. It recovered to 47 +/- 5 mL/min/100 g after removal of the clamp. Cerebral perfusion pressure was within the margin of safety during clamping. Histological findings in the brain showed the effect of congestion in 1 monkey, but the change was slight. The electroencephalogram and electrocardiogram showed no abnormalities in this experiment. In conclusion, one-hour clamping of the superior vena cava with the azygos vein ligated was safe in 6 cynomolgus monkeys. We believe that in the clinical setting, one-hour occlusion of the superior vena cava would result in findings similar to those in this study, unless particular complications, such as arteriosclerosis or a cerebrovascular disorder, exist.

Animals↗
PubMed1989

Correlation among lung damage after radiation, amount of lipid peroxides, and antioxidant enzyme activities.

The correlation between lipid peroxidation and morphologic changes was examined in Sprague-Dawley rat lungs after 30 Gy single thoracic radiation. The rats were sacrificed every week until the end of the fifth week after radiation. The left lungs were used for the measurement of lipid peroxides and antioxidant enzymes activities. The right lungs were examined by light and electron microscopy. Amounts of lung lipid peroxides were within normal limits, and no cellular degenerative changes were observed in the lungs except for subendothelial and interstitial edema 2 weeks after radiation. Lipid peroxides drastically increased and marked degenerative cellular changes such as edematous swelling, vacuolation, and destruction of cell membranes occurred in the alveolar septa following the third week after radiation. The activities of catalase were significantly higher during the period from the second to the fifth week and those of superoxide dismutase and glutathione peroxidase increased at the end of the fifth week. Our results demonstrated that the acceleration of lipid peroxidation was well correlated with the morphologic expression of cell injury in the irradiated lungs.

Animals↗
PubMed1989

Paralytic shellfish toxins in bivalves which are not associated with dinoflagellates.

Paralytic shellfish toxins (PSP toxins) were detected in the freshwater bivalve Corbicula sandai collected from Lake Biwa, Shiga Prefecture, Japan, and marine mussel Septifer virgatus from Mutsu Bay where known causative dinoflagellates and their cysts have never been observed. The toxin profile of C. sandai and S. virgatus was considerably different from suspected causative organisms Aphanizomenon flos-aquae and Protogonyaulax spp., respectively. The causative organism(s) responsible for PSP toxins in these waters is at present unknown.

Animals↗
PubMed1989

Longevity of expanded polytetrafluoroethylene grafts for superior vena cava.

We previously reported that the expanded polytetrafluoroethylene (ePTFE) graft for superior vena cava (SVC) substitution presents the problems of flexion and kinking when the graft is long. We therefore replaced the SVC of dogs with two types of prosthetic substitutes, ePTFE (Gore-Tex) and spiral-supported ePTFE (Im/praflex), and evaluated the long-term patency of the prosthetic substitutes. Total replacement of the SVC was performed in 9 adult mongrel dogs. The substitutes were ePTFE and spiral-supported ePTFE in 5 and 4 dogs, respectively. The animals were killed about 3 years after replacement of the SVC, and the harvested specimens were histologically examined by light microscopy and scanning electron microscopy. Evaluation of ePTFE revealed late occlusion in 1 of 5 dogs. The spiral-supported ePTFE showed patency in all dogs. In the group with ePTFE grafts, light microscopic examination revealed abnormalities of endothelial cells, granulation, and necrosis. There was no hyperplasia of the subendothelial connective tissue near the center. In the animals with spiral-supported ePTFE grafts, the subendothelial connective tissue showed favorable growth even in the center of the reconstructed site. There was no granulation in the spiral-supported ePTFE group. Scanning electron microscopic examination in the ePTFE group showed that endothelial cells were spindle-shaped and had an irregular surface. The spiral-supported ePTFE group showed an almost regular form of endothelial cells and no abnormalities except for the slightly spindled shape in the center. Therefore, we recommend that spiral-supported ePTFE should be used as an SVC substitute in clinical situations.

Animals↗
PubMed1989

Primary ornithine transcarbamylase deficiency. A case report and electron microscopic study.

Histological and ultrastructural findings obtained upon examination of a liver biopsy specimen from a 2-year-old girl with primary ornithine transcarbamylase (OTC) deficiency are presented. The OTC activity in the hepatic tissue of the patient was 7% that of the normal level. Light microscopic observation showed diffusely swollen hepatocytes with pale or empty cytoplasm due to accumulation of glycogen. Neither fat degeneration nor necrosis was evident. Electron microscopy revealed strikingly abnormal hepatocyte mitochondria, which showed marked polymorphism with elongation and enlargement, ring- or dumbbell-shaped configurations, and irregular distribution and shortening of the cristae. Mitochondria showing degenerative alterations such as swelling and rarefaction, which have been reported in cases of Reye's syndrome, were present, but their number was very small. Other organelles showed no remarkable change. It is suggested that the mitochondrial changes seen in OTC deficiency are essentially different from those in Reye's syndrome, which otherwise is clinically and biochemically very similar to OTC deficiency.

Child, Preschool↗
PubMed1989

Scanning electron microscopic studies on the subepithelial tissue of the gastrointestinal mucosa of the rat.

The three-dimensional architecture of the subepithelial tissue of the gastric, the small and the large intestinal mucosa of the rat was observed by scanning electron microscopy (SEM) after removal of cellular elements through prolonged osmication followed by ultrasonication (the method by Highison and Low, 1982), or by cell-maceration with a low temperature NaOH solution (the method by Ohtani, 1987). The basal lamina was exposed by the former method, and the collagenous fibrous sheet immediately under the basal lamina was disclosed by the latter. The surface of the subepithelial tissue is grossly smooth in the pyloric gland and crypts of the small and the large intestine. However, in the fundic glands of the stomach, the surface structure of the subepithelial tissue greatly differs according to glandular location. In the pit of the fundic glands, the surface of both the basal lamina and the sub-basal laminar fibrous sheet is smooth. In the neck region, however, shallow round depressions are seen. The most striking feature of the subepithelial tissue of the fundic glands is the presence of numerous hemispherical concavities in the middle and basal regions of the glands which harbor parietal cells. On the surface of the small intestinal villi, the basal lamina is elevated by the underlying capillary network and forms a meshwork of ridges that surround shallow basins in which numerous round fenestrations 1-5 microns in diameter are seen. The fibrous sheath of the marginal arteriole is observed as a cord-like protuberance on the apical margin of the villi; this suggests its role in the maintenance of the structural integrity of the villi. In the large intestine, well defined round fenestrations are clearly seen, mainly distributed on the upper third of the crypts, and continuing to the lamina propria.

Animals↗
PubMed1989

[Study of strengthening and stress distribution of porcelain jacket crowns constructed with twin foil technique. 2nd report].

McLean and Sced have reported (J Dent Res, 56: 1067-1069, 1977) a procedure for a reinforcement of the porcelain jacket crown, which improved the resistance to a fracture as a result of inhibiting the propagation of cracks into brittle materials, so called the twin foil technique. The purpose of this study is to evaluate the clinical application of this technique. The FEM analysis revealed that the same magnitude of surface tensile stress and no difference of the stress pattern were observed between porcelain jacket crowns constructed with a conventional and the twin foil technique. As the internal tensile stress concentrated in a platinum matrix of the twin foil technique, the stress distribution in a core layer reduced to about 20-35% compared to that of the conventional technique. This is explained by the mechanical and chemical bonds between a platinum matrix and a core porcelain and also by extreme high young's ratio of platinum. We can assume the similar finding from the fractography of the conventional porcelain jacket crown. But contrary above results, no significant differences of the strength were observed in both the presence and the absence of a platinum matrix in the fracture test. From the fact describe above, we may conclude that the tin coated platinum matrix contributes slightly to the strengthening of the porcelain jacket crown.

Crowns↗
PubMed1989

Main long bones of limbs of the Jomon people--proportions in their lengths.

The proportional relationships among the lengths of main limb bones comprising the humerus, radius, tibia and femur of the Jomon people are examined by means of comparison with those of the Kofun and recent Japanese. The disto-proximal indices (the radio-humeral and tibiofemoral) of the Jomon are significantly greater than those of the comparison ages, but the humero-femoral index, as a intermembral, is significantly smaller. Logarithmic plots showing the relation between each two bones, indicate no significant age differences among the inclinations of regression lines corresponding to allometry coefficients. However, significant age differences among the levels of lines were found. According to previous studies, there may be two factors affecting the proportions among limb segments, one biomechanical and the other thermal. The adaptation to mode of life, such as hunting of quick moving animals, appears to be a more reasonable interpretation of the relatively long distal segments (high disto-proximal indices) of the Jomon people.

Adolescent↗