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Biomedical subjects

T Itano

Publications and source records attributed to T Itano.

At least 109 records · Page 6Linked to original sources
PubMed1980

Interactions of basic polypeptides and proteins with calmodulin.

Low concentrations (less than 10 microgram/ml) of a number of highly basic polypeptides inhibit the calmodulin-stimulated cyclic nucleotide phosphodiesterase. Inhibitory compounds include synthetic polypeptides [polylysine (D and L) and polyarginine] and basic proteins (protamine, histones H1, H2A, H2B, H3 and H4 and myelin basic protein). Polylysine of mol.wt. about 2000 or higher was inhibitory, but pentalysine did not inhibit. Other basic proteins and compounds did not inhibit, including bradykinin, spermine and putrescine. In mixtures of calmodulin and basic protein, complexes were formed whether Ca2+ was present or not. This was true for polylysine, myelin basic protein and histone H2B. These interactions suggest that the inhibition of the phosphodiesterase is due to interaction of these basic proteins with calmodulin. The wide variety of basic polypeptides and proteins that affect the calmodulin stimulation of phosphodiesterase indicates that these interactions are not specific.

Calcium-Binding Proteins↗
PubMed1979

Co-existence of inhibitory and stimulatory factors modulating cell proliferation in rat liver cytoplasm.

Factors that inhibit and stimulate cell proliferation were found to coexist in rat liver supernatant. The inhibitory and stimulatory factors were separated by ethanol fractionation. Both factors were sensitive to heat- and trypsin-treatment. The activity of the inhibitor was diminished by partial hepatectomy. The inhibitor from normal livers inhibited DNA and RNA synthesis in the L-cell system, but the same fraction from regenerating livers caused little or no inhibition of nucleic acid synthesis. The stimulatory factor from regenerating livers had a stronger effect on cell proliferation than that of normal livers. Furthermore, the inhibitor from normal livers depressed DNA synthesis in vivo in regenerating livers.

Animals↗
PubMed1979

Partial purification and biological activities and properties of chick growth factors.

Cellular stimulating factors on cell proliferation in the supernatants of chick embryo carcases and adult muscles were studied. There were plural stimulating factors in embryonic and adult muscular supernatants that promoted cell proliferation without any supplement of sera and other materials. Salting-out methods with ammonium sulfate, ethanol fractionation, and isoelectric precipitation were used to isolate the stimulating factors, and these three methods proved the presence of plural stimulants on cell proliferation in the supernatants of chick embryo and adult muscles. The stimulants had altered physico-chemical properties and biological activities due to embryological development. The embryonic stimulants enhanced the synthesis of DNA and protein remarkably, and RNA synthesis in whole cell systems slightly. The muscular stimulants enhanced protein synthesis without any stimulation of DNA and RNA synthesis. Partial purification of the stimulants from the ethanol fractions was performed by DEAE-cellulose chromatography and Sephadex gel chromatography.

Animals↗
PubMed1978

[Analysis of the right ventricular function by simulation (author's transl)].

In the previous experiments it was reported that either the interventricular septum of the free wall of the right ventricle was replaceable with a non-contractile prosthesis. It was also reported that a new chamber constructed on the epicardium had capability of producing a pulsatile pressure. This study was to determine contribution of the septum and the free wall on performance of the right ventricle by using a simulator. Left-ward shift of the interventricular groove was not found along the basal half of the long axis and was limited only along the apical half. Bulging of the septum toward the right ventricular cavity did not occur at all, but on contrary the septum moved toward left, denying contribution of the septal movement to pump action of the right ventricle.

Animals↗
PubMed1977

Mechanodynamics at the interventricular sulcus--reciprocal effect of the ventricles on the ventricular function.

The forces acting on IVS were analyzed to delineate reciprocal effects of the two ventricles on the ventricular fucntion as a whole. The resultant force (FT) was dependent on the LV pressure but independent on the RV pressure. But the composite forces (F1 and F2) of FT were affected by the LV and RV pressures. In a normal heart F1 increased with increasing LV and/or RV pressures. But in F2 increase occurred only with increasing RV pressure. In the LV pressure increase occurred only when the RV pressure was 10 mmHg and decrease did when the RV pressure was 50 mmHg, while stable at 30 mmHg. Directions of both the forces (F1 and F2) diverged as the RV pressure increased and the LV pressure decreased. When FRV was hypertrophic, increases of the magnitudes of the forces were decreased when the pressures of the LV and RV were higher. The angle between the forces was also decreased so that the efficiency of the forces was risen. When a portion of the ventricles lost its contractility, FT increased, particularly, when FLV lost its contractility. But these increases seemed to well be within range of compensation.

Biomechanical Phenomena↗
PubMed1977

Plural growth factors in the supernatant of embryos and adult muscles of chickens.

An attempt was made to isolate the cell proliferation stimulation factors in the supernatant of embryo carcases and adult muscles of chickens. Evidence was obtained for the presence of at least two or more stimulating factors in both the embryonic and adult muscular supernatants. These factors did not require a supplement of sera or other supporting agents. Furthermore, the use of the salting-out method with ammonium sulfate revealed two or more growth stimulants in the supernatant of chick cells.

Animals↗
PubMed1975

Prediction of prognosis in open-heart-surgery by regional difference in leg surface temperature.

Change of the surface temperature of the leg during open-heart-surgery was determined in five patients, in whom either side of the femoral artery was ligated for cannulation. While the surface temperature at the patella was least influenced, that at the ankle paralleled closely the changes in the core body temperature and blood supply to the leg. Their difference (P-A difference) was studied to see if they can be used to predict prognosis of patients undergoing open-heart surgery. The P-A difference was followed for several hours after the open-heart surgery. It was marked positive when the surface temperature at the patella was higher than that at the ankle. Total of 54 patients were studied. Only one out of 29 patients with negative P-A difference succumbed. This is in sharp contrast to the 25 remaining patients with positive P-A difference, from whom as many as 12 died. In addition, the postoperative course of the 13 survivors from the latter group was more eventful. Since P-A difference seemed to indicate accurately cardiac output by reflecting the state of the peripheral circulation, it can be used as a useful parameter in prediction of the prognosis in open-heart surgery.

Adolescent↗