Biomedical subjects

T Tomura

Publications and source records attributed to T Tomura.

6 recordsLinked to original sources

PubMed1992

[Studies on early stage changes of peroxide lipid in isoproterenol-induced myocardial injury].

The amount of peroxide lipid in vivo in the early stage of the experimental model of myocardial infarction in a rat induced by the administration of isoproterenol (Isp) was measured as the value of malonic dialdehyde (MDA). The model of myocardial infarction was made by giving 75 mg/kg of Isp to the rat weighing 270 +/- 10 g. After the administration of Isp, the amounts of lipid in the serum and in the myocardial tissue were measured, and a blood chemistry test (glutamic oxaloacetic dehydrogenase, glutamic pyruvic transaminase, lactate dehydrogenase, free fatty acid, creatine kinase) was simultaneously carried out on the serum. The value of the amount of peroxide lipid in the serum began to elevate 3 h after the administration of Isp and reached a maximum value at 6 h. The value of the amount of peroxide lipid in the tissue began to elevate 30 min after the administration and reached a maximum at 3 h. Each blood chemistry disclosed the elevation 30 min after the administration. As mentioned above, the production of peroxide lipid in vivo on the myocardial disorder in the early stage after the administration of Isp and the biochemical changes showed a significant correlation. From these results it is suggested that the myocardial disorder induced by the administration of Isp has already developed at 30 min after the administration.

Animals↗

PubMed1991

[Morphological study of human thyroid papillary carcinoma cells in collagen gel culture].

Human thyroid papillary carcinoma cells (surgical materials) were cultured in a monolayer or a collagen gel system. In the monolayer culture, degeneration and necrosis of cancer cells were observed after 10 days of culture. In the collagen gel culture, degenerative necrosis were observed 14 days culture. In histopathological observation monolayer cells proliferated in pavement-like form without forming any colony. On the contrary, collagen gel culture cells formed branching-type colonies and spheroid-type colonies. Those results suggested that papillary carcinoma cells can be cultured more like in vivo in collagen gel culture than monolayer culture.

Carcinoma, Papillary↗

PubMed1988

Procainamide-DNA interaction.

The interactions of procainamide with DNA were studied by neutral and alkaline sucrose gradient sedimentation and sequential action of 2 enzymes: a mammalian repair endonuclease and bacterial DNA polymerase I. Sucrose gradient sedimentation shows that in the absence of photosensitization, the interaction of procainamide with DNA did not modify DNA sedimentation in alkaline or neutral sucrose gradients. In contrast, when a photosensitized DNA procainamide mixture was placed on sucrose gradients, the peak appearing on alkaline sucrose gradient after treatment with endonuclease was shifted toward the lower molecular weights, indicating that strand breaks had developed in the photosensitized procainamide DNA. Incubation of a [32P] labeled photosensitized procainamide-DNA complex with a repair endonuclease and DNA polymerase I released the label in the acid soluble fraction, indicating that only the photosensitized procainamide-DNA complex was susceptible to the endonucleolytic attack. There was only negligible release of the label in the acid soluble fraction without exposure of the DNA-procainamide mixture to light. The incorporation into DNA of [3H]-TTP (tritium labeled triphosphates) in presence of DNA polymerase I was inhibited when the photosensitized procainamide-DNA complex was used as substrate. However, after treatment of the photosensitized DNA complex with the repair endonuclease, the incorporation of [3H]-TTP was increased and reached values close to that observed with DNA unexposed to light, suggesting that the endonuclease functions as a repair enzyme.

Animals↗

PubMed1975

The effect of a mammalian repair endonuclease on x-irradiated DNA.

DNA was extracted from rat liver of non-irradiated animals, and was irradiated in vitro, and from animals which received whole body doses of X-radiation. Sedimentation on neutral and alkaline sucrose gradients as well as measurements of 32P release after sequential treatment with endonuclease and alkaline phosphatase and determination of triphosphate incorporation after the sequential treatment with endonuclease, alkaline phosphatase and DNA polymerase indicated that DNA irradiated in vivo and in vitro were effective substrates for the mammalian repair endonuclease. The experiments suggest that in addition to strand breaks, X-radiation causes base damage and they have provided a plausible explanation for the formation of double strand breaks in DNA irradiated in vivo.

Alkaline Phosphatase↗

PubMed1975

Alterations of liver DNA after x-irradiation. Reassociation and hybridization with nuclear RNA.

When RNA is extracted either from irradiated or unirradiated rat livers, no difference in its ability to hybridize with DNA is detectable. In contrast, the ability of DNA extracted from irradiated animals to hybirdize with RNA is decreased, probably as a result of DNA fragmentation. Sedimentation of X-irradiated DNA on sucrose gradients separates a small (low molecular weight) from a large peak (high molecular weight). The hybridization capacity for RNA of the large molecular weight DNA is similar to that of unirradiated DNA, but that of the small molecular weight is DNA reduced. After irradiation of the denatured DNA in vitro, the reassociation of DNA is inhibited, which suggests that DNA strands have lost part of their complementariness.

Animals↗

PubMedDate not supplied

[Studies on early changes in myocardial electrolytes and histological reaction in isoproterenol-induced myocardial injury].

To determine morphological changes in the very early stage of damage and recovery of myocardial fibers in relation to electrolytes and water content in the myocardium, experimental myocardial infarcts were produced after injection of 75 mg/kg isoproterenol (Isp) to rats weighing 270 +/- 10 g. Electrolytes were examined by an atomic absorption spectrophotometer, and histologic examination was performed by light and electron microscopy. At 30 min after Isp injection, Ca and water contents of myocardium increased, but Mg decreased. These myocardial damages showed a maximum level from 6 to 12 h after injection of Isp. It consisted of reversible injury of muscle fibers represented by eosinophilic and fatty degeneration, intermingled with coagulation necrosis of fibers which was irreversible. Most of these eosinophilic degeneration fibers recovered to normal fibers between 12 h and 3 d after the injection. The chronological changes of Ca, Mg, and water contents were well correlated to the morphological early changes of myocardial fibers, and this experimental model by using Isp may be useful for examining the recovery of damaged myocardial tissue and estimating the effects of therapeutics.

Animals↗