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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 667 records · Page 37Linked to original sources
PubMed1981

[Changes of blood-brain barrier in the ethylnitrosourea induced rat glioma (author's transl)].

Capillary permeability of rat brains bearing ethylnitrosourea induced rat glioma was measured with quantitative autoradiography. In the small tumors (less than 2mm in diameter), no changes in capillary permeability was noted. When tumors became larger and neovascularization of the tumor occurred, increase in capillary permeability was evident. This change was more prominent in the center of the tumor than in the periphery. In the large tumors, the capillary permeability was markedly increases, and the value was similar to that in the choroid plexus. This indicates that blood-brain barrier(BBB) completely disappeared in the large tumors. This BBB change may be the main cause of tumor induced brain edema. The data also provide the information about pharmacokinetics of water soluble drugs in the brain tumors.

Animals↗
PubMed1981

[Regional blood flow in the ethylnitrosourea induced rat glioma (author's transl)].

Regional cerebral blood flow of rat brains bearing ethylnitrosourea induced glioma of various size was investigated with 14C-antipyrine autoradiography. In the small tumors (less than 2 mm in diameter), blood flow was uniformly reduced when compared to the adjacent brain. Even in tiny tumors (0.3-0.4 mm in diameter), reduction in blood flow was evident. In the medium (2-4 mm in diameter) and large (greater than 4 mm in diameter) tumors, the blood flow increased in the viable center of the tumor and decreased in the necrosis and peripheral edge. High blood flow in the viable center may be attributable to the neovascularization of the tumor. Blood flow in the brain tissue adjacent to medium and large tumors was lower than control brain tissue probably due to local edema. This reduction in blood flow may be partly attributable to the appearances of the focal neurologic deficits. The result obtained may provide some information about growth regulation of glioma and also pharmacokinetic delivery of chemotherapeutic drugs to the malignant brain tumors.

Animals↗
PubMed1980

Hydrophobicity determined by a fluorescence probe method and its correlation with surface properties of proteins.

The fluorescence method of Sklar et al. (Sklar, L.A., Hudson, B.S. and Simoni, R.D. (1977) Biochemistry 16, 5100-5108) using cis-parinaric acid as a probe was applied to determine the effective hydrophobicity of proteins. The initial slope (S0) of fluorescence intensity vs. protein concentration plot was used as an index of the protein hydrophobicity. A good correlation was observed for S0 of native proteins, denatured proteins and surfactant-bound proteins with an effective hydrophobicity determined by the hydrophobic partition method. The effective hydrophobicity determined fluorometrically showed significant correlations with interfacial tension and emulsifying activity of the proteins studied. The fluorescence technique using cis-parinaric acid is useful for determination of the effective hydrophobicity, as the procedure is much simpler and quicker than hydrophobic chromatography and hydrophobic partition.

Animals↗
PubMed1980

Increases in coronary vascular resistance related to high arterial oxygen tension in dogs.

It is known that oxygen inhalation induces coronary vessel constriction as well as brings about a reduction in myocarial oxygen consumption. The present study was performed to clarify whether or not this constriction of the coronary vessels resulting from oxygen is secondary to the reduction in myocardial oxygen consumption. The regional myocardium in 12 mongrel dogs was perfused with femoral arterial blood at a constant rate of flow. While maintaining myocardial oxygen consumption equal by adjusting heart rate, coronary vascular resistance was compared under the two following conditions: 1) perfusion of the coronary artery with the dog's own femoral arterial blood (pO2 : 95 +/- 14 mmHg) and 2) perfusion with blood with a high level of oxygen tension (pO2 : 497 +/- 56 mmHg). Coronary vascular resistance was increased (p < 0.001) from 3.00 +/- 1.25 to 3.36 +/- 1.28 mmHg/ml/min by incresing the pO2 in the perfusing blood, even though myocardial oxygen consumption was kept at the same level. This increase in coronary vascular resistance resulting from the increase in oxygen tension was independent of the coronary perfusion rate as well as independent of the presence or absence of myocardial ischemia. This suggests that coronary vasoconstriction due to oxygen is not secondary to decreases in myocardial oxygen demand.

Animals↗
PubMed1980

Variable prognosis in congestive cardiomyopathy. Role of left ventricular function, alcoholism, and pulmonary thrombosis.

Prognosis of 36 patients with congestive cardiomyopathy was studied in relation to various clinical factors. Half life of the survival curve after overt heart failure was about 7 years. Although left ventricular function was a major determinant of clinical course in congestive cardiomyopathy in general, its relation to prognosis was variable according to the type of cardiac involvement. In peripartal cardiomyopathy and in a type of cardiomyopathy named subacute cardiomyopathy with pulmonary thrombosis in this paper, factor(s) other than left ventricular function, possibly including pulmonary thrombosis, may be operative as more important determinant of extremely poor prognosis in these subtypes. Alcoholic cardiomyopathy was also unique in its favorable prognosis in association with reversible cardiomegaly following abstention from alcohol.

Adult↗
PubMed1979

Extensive hepatic cell necrosis produced by the Shwartzman mechanism.

Acute, severe, and extensive necrosis of the liver was produced in pregnant and non-pregnant female adult rabbits by the Shwartzman mechanism. Shwartzman reagent (E. coli endotoxin) was administered in various combinations by three routes of injection, the portal vein (mesenteric vein), the bile duct, and the ear vein. Morphologic changes of the extrahepatic organs were minimal. The similarity to massive necrosis in human liver and the effect of pregnancy on hepatic necrosis in rabbit and man were discussed. The lesion is presented as a new animal model for acute massive hepatic necrosis and is proposed as a third category of Shwartzman reaction, designated the univisceral type.

Acute Disease↗
PubMed1979

In vitro maturation of mesencephalic dopaminergic neurons from mouse embryos is enhanced in presence of their striatal target cells.

Long-term survival of mesencephalic and striatal cells from mouse embryos in dissociated primary cultures is described. Catecholaminergic neurons in mesencephalic culutres were identified histochemically and by measuring [3H]dopamine uptake and synthesis from [3H]tyrosine. According to experiments using specific inhibitors of catecholamine uptake, at least two-thirds of the catecholaminergic neurons are dopaminergic. These neurons differentiated whether or not striatal target cells were present, but striatal cells stimulated the development of the dopaminergic neurons. [3H]Dopamine uptake was increased by at least 2-fold regardless of the age of the cocultures (4-15 days). Enhanced [3H]dopamine synthesis was also observed (at least 2-fold) at later times (12-15 days).

Animals↗
PubMed1978

Anti-testosterone antisera produced in mice of different strains and sexes.

Specific anti-testosterone antiserum was obtained from mice of the strain C57B1/6. Testosterone 3(O-carboxymethyl)oxime-keyhole limpet hemocyanin conjugate was administered to male and female mice of the strains C57B1/6 (H-2b), DBA/2 (H-2d), (C57B1/6 x DBA/2)F1, (H-2b/d), and AKR (H-2k). Antisera obtained from male and female C57B1/6 mice were more specific for testosterone than those from the other strains, and the cross-reaction with 5alpha-dihydrotestosterone was 25.0 and 29.2%, respectively. The titer of antiserum from C57B1/6 mice was the highest and that of antiserum from DBA/2 mice was the lowest. On the other hand, the titer of antiserum from the female was higher than that of antiserum from the male in each strain. These results indicate that the mouse strain and sex differences are important factors for antibody formation from challenged antigen.

Animals↗