Search PubMed⌕ Search

Biomedical subjects

T Kokubo

Publications and source records attributed to T Kokubo.

At least 307 records · Page 17Linked to original sources
PubMed1985

Embolism detection and prevention using scintigraphy during therapeutic arterial blockade.

We describe an application of simple scintigraphic localization of therapeutic gelatin emboli during and after transcatheter arterial embolization using gelatin particles labeled with technetium 99m. This scintigraphy required an additional 15-30 minutes and can be useful for prevention of serious complications and for early detection of adverse embolisms.

Arteries↗
PubMed1984

Correlative morphological and biochemical studies on monocrotaline-induced pulmonary alterations in rats.

A single s.c. injection of 60 mg/kg of monocrotaline to rats induced pulmonary alterations characterized by hyaline thrombi of capillaries and arterioles, focal necrosis of alveolar walls, and medial thickening and intimal hyalinosis of arteries. Such pathological alterations became apparent 7 days after injection and thereafter progressively developed with the passage of time. Histometrical examination revealed a reduction of the alveolar surface area in a unit volume of lung tissue in these rats. Biochemically, lung angiotensin-converting enzyme activity was estimated to have reduced in parallel with the development of pulmonary alterations while plasma angiotensin-converting enzyme activity was unchanged throughout the experimental period.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1984

Three-dimensional morphological study of rat gastric lesions induced by N-methyl-N'-nitro-N-nitrosoguanidine. Structural atypia in carcinoma and non-carcinomatous lesions.

Lesions of the rat glandular stomach induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were classified into 4 categories: intramucosal lesions; polypous lesion; downward-growth lesions, and unequivocal adenocarcinomas. Each lesion was examined by three-dimensional reconstruction from serial sections to study the spacial arrangement of the glandular tubules. In the intramucosal lesions, the tubules showed tree-like branchings. In the polypous lesions and downward-growth lesions, the tubules were interconnected to form a three-dimensional network. In unequivocal adenocarcinomas, the tubules appeared separated and were dispersed into nests. These findings indicate that interruption of continuity of the epithelium in proliferated tubules is a possible sign of malignant transformation. Erosions were always observed in the intramucosal, the polypous and the downward-growth lesions. There were locations in the tubular system where the tubules became so attenuated as to resemble cord like structures. Inflammatory reactions were always demonstrable in the intertubular spaces in such lesions. These findings indicate that MNNG-induced anatomical changes may participate in the formation of erosions by causing local obstruction of the ductules.

Adenocarcinoma↗
PubMed1984

Pathogenesis of paraquat-induced pulmonary hemorrhage in hamsters with special reference to arterial constriction.

Three dimensional reconstructions of pulmonary arteries and the bronchial tree were made to evaluate the cause of hemorrhage in the lungs of hamsters treated with a single intraperitoneal injection of paraquat at a dose of 15 mg/kg b.w. The hemorrhage corresponding to the respiratory bronchiolar segment formed the minimum hemorrhagic unit; larger hemorrhages were composed of conglomerations of such units. The respiratory bronchiolar segment was fed by a single respiratory bronchiolar arteriole which had a distinct muscular medial coat. No evidence of breakage of the arterial wall passing through the hemorrhagic lesion could be detected even by careful observation with serial histological sections. Accordingly, the cause of the lung hemorrhage was sought in the combined effects of paraquat toxicity to the capillary endothelium and vasoconstriction of the respiratory bronchiolar arterioles.

Animals↗
PubMed1984

A comparative histometrical analysis of renal inner medulla of man, swine, dog and hamster.

Quantitative estimations of the total circumference (in mm) of Henle's thin segment (TCH) and of the collecting tubules (TCC) in the renal inner medulla of man, swine, dog and hamster were made at different distances (X) from the papillary apex. The results were expressed as exponential functions of X, the distance in mm along the medullary ray from the papillary apex to a certain point of the inner medulla, as L = AeBX. In man and swine, TCH was greater than TCC towards the external border of the inner medulla. However, in dog and hamster TCH was less than TCC along the entire inner medulla. The exponents of TCH showed nearly constant values (hamster: 0.68, dog: 0.75, man: 0.55, swine: 0.56), but those of TCC had values (hamster: 0.92, dog: 0.57, man: 0.28, swine: 0.26) correlated with the ability for concentration of urine. These findings indicate a good correlation between the ability to concentrate urine and the structure of the collecting tubules of the inner medulla, suggesting that the structure of the collecting tubules in the inner medulla affects the mechanism of urinary concentration.

Animals↗
PubMed1984

Nutritional factors influencing the results of toxicology experiments in animals.

The purpose of this paper is to present experimental data illustrating the importance of a toxicopathological basis necessary for understanding the role of nutrition on drug toxicity. Nutritional status constitutes an important factor capable of modulating the results of animal experiments in toxicology. Therefore, it is necessary in any toxicity testing to consider the effects of nutrition on drug toxicity and, at the same time, the effect of drug toxicity on the nutritional state of animals.

Animals↗
PubMed1984

Effects of sodium chloride, saccharin, phenobarbital and aspirin on gastric carcinogenesis in rats after initiation with N-methyl-N'-nitro-N-nitrosoguanidine.

Sodium chloride, saccharin sodium, phenobarbital sodium and aspirin were tested for tumor-promoting activity in the glandular stomach of rats after initiation with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) coupled with administration of a high salt diet. Male outbred Wistar rats were given MNNG in the drinking water (100 mg/liter) for 8 weeks, and during this period they were fed on diet supplemented with 10% sodium chloride. Thereafter, they were divided into 5 groups and fed on the basal diet or one of various diets supplemented with 10% sodium chloride, 5% saccharin, 0.05% phenobarbital or 1% aspirin until the end of the experiment. All animals were killed at the 40th experimental week for necropsy and histological examination. The incidence of adenocarcinoma was increased in the group given sodium chloride following initiation by MNNG and sodium chloride as compared with the group given MNNG and sodium chloride initiation only, but not significantly. However, the incidence of preneoplastic hyperplasia was significantly increased in this group. Saccharin also enhanced the development of adenocarcinomas of the glandular stomach. The results indicated that dietary administration of sodium chloride or saccharin after MNNG tends to promote tumor development. Phenobarbital or aspirin did not enhance tumor development, aspirin in fact rather showing a tendency to decrease the tumor incidence.

Adenocarcinoma↗
PubMed1984

Spontaneous tumors of the nervous system and associated organs and/or tissues in rats.

Spontaneous tumors of the nervous system and associated organs and/or tissues in 346 male and 346 female F344/DuCrj rats and 200 male and 177 female Slc:Wistar rats were examined. The main neurogenic tumors observed were gliomas and neurinomas, which were detected in both strains of rats. Out of 7 gliomas, 6 were found in the brain and 1 in the spinal cord, and out of 4 neurinomas, 2 were in the trigeminal nerves and the other 2 were in the spinal nerves. In addition, other types of tumors (2 granular cell tumors in the brain, 1 pinealoma, 3 ganglioneuromas in the adrenal gland, 1 undifferentiated carcinoma in the nasal cavity and 1 chordoma in the posterior neck region) were observed.

Animals↗