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Biomedical subjects

T Omata

Publications and source records attributed to T Omata.

At least 109 records · Page 6Linked to original sources
PubMed1984

[Changes in grading at bladder tumor recurrence].

Today, transurethral resection to superficial bladder tumors is an important method, although frequent recurrence is a problem. We examined whether the degree of progressiveness could be determined at the time of recurrence and therapeutic manner decided from only the grading. Forty four cases which had recurred over twice and in which grading was changed during recurrence were examined. Recurrence occurred twice in 19 cases, and 3 times in 13 cases. Two patients had the largest number of recurrences, i.e., seven. The patients were divided in 3 groups. The 1st group consisted of 25 cases not worsening in grade from initial and recent transurethral resection-bladder tumor (TUR-Bt). The 2nd group consisted of 9 cases who had progressing grading. The 3rd group consisted of 10 cases who died of carcinoma. In the first group, grading decreased in 17 cases. Eight cases in the 3rd group were grade 4. We found that recurrent cases of bladder tumor did not always progressive, grading, being rather decreased than progressing in group 1. However, most of the grade 4 cases died of carcinoma. In conclusion, recurrent TUR-Bt in low grade bladder tumor patients may not be progressive, but grade 4 cases at recurrence require radical operation.

Adult↗
PubMed1983

Electron microscopical studies on the nerve endings of the outer hair cells in acoustically exposed rabbits.

The afferent and efferent nerve endings of the outer hair cells of the rabbit after acoustic exposure were investigated under the electron microscope. After acoustic stimulation, the afferent and efferent nerve endings of normal range were respectively 57 per cent and 64 per cent. This result suggests that half of the afferent and efferent nerve endings maintain their function under the conditions of this experiment. An abnormal inclusion body forming an oblong dense body and cistern in addition to the postsynaptic cisterna was observed. The active zone and the vesicular gap-structure of the synapse are discussed.

Acoustic Stimulation↗
PubMed1983

[Metachronous triple malignant lymphoma of the stomach].

A 72-year-old female who had undergone partial gastrectomy (Billroth I method) 8 years earlier because of a diagnosis of malignant carcinoma of the stomach (histopathological diagnosis: ML. Histiocytic, Diffuse--Rappaport--) visited our hospital because of dysphagia for the past three months. X-ray and fiberscopic examination revealed the same malignancy in the remnant stomach. Curative extirpation of the remnant stomach, resection of the lower esophagus and pancreatosplenectomy were performed. There were two lesions in the resected specimen. One was a large tumor of Borrmann 3 type (8 cm in diameter) at the EGJ; the other was a small IIc-like tumor (2 cm in diameter) at the surgical stump on the lessercurvature. These three metachronous malignant lymphomas returned the same pathological findings. Compared to carcinoma, malignant lymphoma of the stomach occurs more frequently in the fornix and the tendency for multiple occurrence is strong. When partial gastrectomy is performed for malignant lymphoma of the stomach, follow-up of the remnant stomach must be carried out carefully.

Aged↗
PubMed1982

Complete nucleotide sequence of the attenuated poliovirus Sabin 1 strain genome.

The complete nucleotide sequence of the genome of the type 1 poliovirus vaccine strain (LSc,2ab) was determined by using molecular cloning and rapid sequence analysis techniques. The restriction fragments of double-stranded cDNA synthesized from the vaccine strain RNA were inserted into the adequate sites of cloning vector pBR322. Sequence analysis of the cloned DNAs revealed that the virion RNA molecule was 7,441 nucleotides long and polyadenylylated at the 3' terminus. When the nucleotide sequence was compared with that of the genome of the virulent parental strain (Mahoney), 57 base substitutions were observed to be scattered all over the genome. Of these, 21 resulted in amino acid changes in a number of viral proteins. A cluster of amino acid changes is located in the viral coat proteins, especially in the NH2-terminal half of the viral capsid protein VP1. These results may imply that the mutations in the VP1 coding region contribute to attenuation.

Base Sequence↗
PubMed1982

Ototoxicity of aminoglycoside antibiotics by rapid intravenous injection.

The ototoxicity and nephrotoxicity of aminoglycoside antibiotics (dibekacin, gentamicin and kanamycin) administered to rabbits by rapid intravenous or intramuscular injections were histopathologically compared. Comparative evaluations between the two routes were further made concerning the levels of the antibiotics in serum and in perilymph. The results revealed that, although the peak serum level after a rapid intravenous injection was significantly higher than that observed after an intramuscular injection, no differences in the transfer into the perilymph, and in inner ear or renal damage were seen between the two different routes. In other words, the results of the present study did not support the conventional idea that the higher the peak blood levels of the aminoglycoside antibiotics, the greater the risk of damage to the inner ear or kidney.

Aminoglycosides↗
PubMed1980

Afferent and efferent nerve endings of the outer hair cells in the rabbit.

The afferent and efferent nerve endings of the outer hair cells of the rabbit were investigated electron-microscopically. The afferent nerve ending was 1.4 X 2.0 microns in size and contained small vesicles, spherical mitochondria, and occasionally multivesicular bodies. The partially thick and dense membranes on either side of the synaptic cleft were observed and this region of the synaptic cleft was high in electron density. This area was considered to be an active zone of the afferent nerve ending. The efferent nerve ending was 4.0 X 6.0 microns in size and contained many synaptic vesicles, many oblong mitochondria, and multivesicular bodies. Synaptic vesicles were concentrated at some sites opposite the synaptic cleft. This area was thought to be an active zone where vesicles discharge their contents into the synaptic cleft. Furthermore, in some places of the synaptic cleft there were gaps (0.16 X 0.68 microns) which contained small vesicles. The gaps in the synaptic cleft have been briefly discussed.

Animals↗
PubMed1979

Electron microscopical and histochemical studies of outer hair cells in acoustically exposed rabbits.

After acoustic exposure, in the infranuclear region of the basal turn histochemically the lactate dehydrogenase activity increased more than normal. In the lower half of the second turn of this region, small vesicles, free ribosomes and coated vesicles decreased in number and cytoplasmic matrix become lower in electron density and lactic dehydrogenase activity decreased. Small vesicles were found to be preferentially distributed in the presynaptic side of the afferent nerve endings. Movement of these small vesicles leads to the speculation that small vesicles have close relationship to the afferent nerve endings.

Animals↗
PubMed1978

Electron microscopical and histochemical studies of outer hair cells in normal rabbits.

The outer hair cells of the rabbit were electron microscopically and histochemically investigated. The results clearly showed that the outer hair cells of the rabbit have no agglomeration of mitochondria in its infranuclear region. This anatomical fact means that the functional mechanism in the outer hair cells of the rabbit may be substantially different from that of other animals which have agglomeration of mitochondria. From the results of the histochemical study, it is reasonably supposed that the anaerobic energy metabolism may ordinarily play the leading part in sustaining the cellular functions in the infranuclear region of the outer hair cells of the rabbit.

Anaerobiosis↗
PubMed1978

Potentiation and its mechanism of cochlear damage resulting from furosemide and aminoglycoside antibiotics.

The severe ototoxic interaction of the combined administration of furosemide and aminoglycoside antibiotics (kanamycin, streptomycin and gentamicin) was studied in rabbits, and its mechanism clarified. Severe damage occurred not only in the inner ear but also in the kidney when both furosemide and aminoglycoside antibiotics were administered to rabbits. Kanamycin concentration after a single injection of kanamycin with furosemide was much higher not only in the perilymph but also in the cerebrospinal fluid and serum than that after a single injection of kanamycin alone. The ototoxic interaction following the combined use of furosemide and aminoglycoside antibiotics seems to be caused mainly by the inhibitory effect of furosemide on the excretion of aminoglycoside antibiotics from the kidneys.

Aminoglycosides↗
PubMed1978

A detection method for lactic dehydrogenase activity in the inner ear.

A method for the detection of lactic dehydrogenase enzymatic activity in outer hair cells of the rabbit is described. The membranous labyrinth with temporal bone was prefixed in glutaraldehyde. After being placed into the incubation medium, it was postfixed in osmium tetroxide. Specimens of the organ of Corti were removed. Then the specimens were embedded in water-soluble glycol and cut with a cryostat for light microscopy, and also they were embedded in Epon and cut for light and electron microscopy. Sectioning of the membranous labyrinth was very easily made when the specimens were embedded in both the water-soluble glycol and the Epon. The structures of the frozen sections as well as the Epon-embedded ones were well preserved. In the frozen sections the preservation and localization of reaction products were thoroughly kept, but monoformazan of the Epon-embedded sections was soluble.

Animals↗