Search PubMed⌕ Search

Biomedical subjects

H Kanaide

Publications and source records attributed to H Kanaide.

At least 181 records · Page 10Linked to original sources
PubMed1984

Effects of diltiazem on the calcium paradox in isolated rat hearts.

Effects of diltiazem (10(-5) M) on the calcium paradox were studied in isolated, perfused rat hearts. After 4 min of calcium-free perfusion, the hearts were reperfused with medium containing 2.5 mM calcium for 15 min at 37 degrees C. During this perfusion, the coronary flow rate was maintained either high (10 ml/min) to produce severe tissue injury of calcium paradox or low (5 ml/min) to produce mild injury. In the high flow rate group, administration of diltiazem during the calcium-free period and calcium-repletion period failed to reduce the overall level of tissue injury caused by calcium-repletion. In the low coronary flow rate group, diltiazem markedly prevented the development of the calcium paradox, in terms of calcium-induced creatine kinase release, recovery of contractile tension development, tissue high-energy phosphate stores and tissue calcium accumulation. These events were irrespective of whether the drug was administered only during the calcium-free period, the calcium-free period and initial 2 min of the calcium-repletion period or the calcium-free period and totality of the calcium-repletion period. Thus, diltiazem appears to exert its protective effect against the mild calcium paradox phenomenon by regulating the ionic environment of myocardial cells during the calcium-free period.

Animals↗
PubMed1983

Myoglobin oxygenation remains constant during the cardiac cycle.

Oxygen saturation of myoglobin (Mb) during the cardiac cycle was recorded spectrophotometrically by incorporating fiber optics in the isolated rat heart perfused using the Langendorff procedure. Oxygen saturation of Mb was continuously measured from absorbancy increments at 581-592 nm of transmitted light through the left ventricular free wall. In addition, quantification in the Mb oxygen saturation induced by the change of wall thickness during cardiac cycle was assessed from the absorbance change at 568-592 nm, namely, dual wavelengths of two isosbestic points. The results show that to obtain actual Mb oxygen saturation the absorbance change induced by the change in the wall thickness has to be subtracted from the absorbance change of 581-592 nm and that the Mb oxygen saturation in a steady state determines the amount of subtraction. On the basis of these procedures, it was found that the myocardial Mb oxygen saturation and hence myocardial oxygen tension during pulsation in aerobic and anaerobic steady state did not vary during the cardiac cycle.

Aerobiosis↗
PubMed1983

Metabolism of glycosaminoglycans of cultured rat aortic smooth muscle cells altered during subculture.

We observed the changes in the metabolism of glycosaminoglycans of cultured smooth muscle cells from the rat aorta during subculture. The primary culture was achieved by the enzymatic dispersion method. The metabolism of glycosaminoglycans in smooth muscle cells was estimated by measuring the incorporation rate of D-[1-14C] glucosamine and [35S] sulphate. Smooth muscle cells were harvested by trypsinization, and glycosaminoglycans were separately extracted and purified from trypsin digest and cells. In the cells of the stationary phase of primary culture, the incorporation of both D-[1-14C] glucosamine and [35S] sulphate into dermatan sulphate was greater than that into heparan sulphate. However, in the trypsin digest, the incorporation of D-[1-14C] glucosamine and [35S] sulphate into dermatan sulphate was less than and equal to that into heparan sulphate. In both the cells and the trypsin digest, the incorporation of D-[1-14C] glucosamine and [35S] sulphate into heparan sulphate decreased and that into dermatan sulphate increased with increase in the number of passages. These results indicate that there is a development of serial modulation in the metabolism of glycosaminoglycans in the cultured smooth muscle cells, in the early passage of subculture and that such should be taken into consideration when analysing the observations.

Animals↗
PubMed1982

Effects of divalent cations on the conversion of fibrinogen to fibrin and fibrin polymerization.

Effects of divalent cations on fibrinogen and its reaction with thrombin were re-examined and correlated to improve definition of mechanisms underlying the acceleration of clot formation by the ions. The rate of release of fibrinopeptides from fibrinogen was not affected by any of the specific ions studied, but increased rates of fibrin monomer polymerization were obtained with all but magnesium ions. Maximal acceleration of monomer polymerization was observed with the divalent ions at concentration of 2.5-5 mM, and no added specific ion effects were observed with much higher levels. The acceleratory ions were found to have a corresponding effect on the solubility of fibrinogen, as judged from acceleration of its precipitation at low temperature. Although magnesium ions had no effect on fibrin monomer polymerization, they did have a low ranking effect on cryoprecipitation. These data confirm that the principal effect of divalent cations in the fibrinogen-fibrin transformation is to accelerate fibrin monomer polymerization, and suggest that the acceleration is associated with effects on the solubility of fibrinogen.

Blood Coagulation Tests↗
PubMed1982

Etiologic aspects of coagulopathy in Takayasu's aortitis.

Sixteen patients with Takayasu's aortitis were studied to evaluate the significance of coagulopathy in the etiology. In the initial stage of the disease (three cases) characterized by severe inflammatory symptoms with aortic lesions localized in the thoracic portion, marked hyperfibrinogenemia, and hypofibrinolytic activity of the plasma were observed. In the intermediate stage (five cases) characterized by moderate inflammation and aortic lesions expanded into thoracic and abdominal portions, hyperfibrinogenemia and hypofibrinolytic activity were also seen; in three of these cases, hypercoagulability was evident because of the presence of fibrinogen derivatives having gamma-gamma-diads in the plasma. When the inflammation subsided after the establishment of aortic lesions, the end-stage (eight cases), hyperfibrinolytic activity with normal plasma fibrinogen was observed. It is suggested that hypercoagulability may be in response to the arterial disease and may possibly play a part in the development of this disorder.

Adrenal Cortex Hormones↗
PubMed1982

Regional myocardial function and metabolism during acute coronary artery occlusion.

Regional changes in myocardial function and oxidative metabolism during acute coronary artery occlusion were recorded spectrophotometrically by incorporating fiber optics in the isolated rat heart perfused by Langendorff's procedure. Oxygen saturation of myoglobin, reduction of cytochrome aa3, and the dynamic wall thickness of the left ventricle were continuously and concurrently measured from absorbancy increments at 581-592 nm, 605-630 nm, and 568-592 nm, respectively. In contrast to a gradual decrease in the extent of systolic wall thickening in anoxia, observed decreases in both the extent and the duration of systolic wall thickening and the appearance of a late systolic bulge occurred within 5 s after the onset of regional ischemia. After 10 s of both anoxia and regional ischemia, oxygen saturation of myoglobin decreased by 50%, but fluorescence of nicotinamide adenine dinucleotide remained at aerobic level which indicated that mitochondrial oxidative energy production might still be maintained. Thus early and pronounced dysfunction of the ischemic region appeared to precede a substantial loss of ATP production.

Adenosine Triphosphate↗
PubMed1982

The anticoagulant effect of chondroitin sulphates isolated from normal and atherosclerotic regions of human aortas.

Chondroitin sulphates (CSs) were isolated from the intima and the media of normal (normal CSs) and atherosclerotic (sclerotic CSs) regions of human aortas. Normal and sclerotic CSs accelerated the inactivation of thrombin by antithrombin III to an equal extent. By this mechanism, both normal and sclerotic CSs prolonged thrombus formation time in a moving stream of platelet-rich plasma and thrombin-catalysed clotting time of platelet-poor plasma. However, anticoagulant activity of sclerotic CSs in thrombin-catalysed fibrin clot formation in platelet-poor plasma was lower than that of normal CSs. The lower anticoagulant activity of sclerotic CSs was due to the greater accelerating effect on the polymerization of monomeric fibrin to form clot, which was the final distinguishable step of fibrinogen-fibrin conversion.

Adult↗
PubMed1981

Reelevation of ST segment on precordial mapping in natural time course following acute anterior myocardial infarction.

Serial recordings of ST segment mapping were performed in 15 patients with acute anterior myocardial infarction. Reelevation of ST segment was observed in all cases between 12 hours and one week after infarction without clinical evidence of reinfarction. There was significant correlation between the magnitude of the sum of ST reelevation (sigma ST) and time to the peak of ST reelevation. The higher was sigma ST at the peak, the later was the appearance of the peak of ST reelevation. sigma ST recorded between 24 and 72 hours after infarction correlated with the extent of abnormal Q (NQ) in the precordial mapping as well as the percent of abnormally contracting segment (%ACS) on left ventricular angiography examined after 4 weeks following infarction. However, there was no correlation between sigma ST recorded at 12 hours after infarction and NQ studied at 4 weeks after infarction. The results indicate that the magnitude of sigma ST changes in time during the course after infarction and that the time of recording is important when sigma ST is used for the estimation of infant size. Reelevation of ST segment should be considered in the study of therapeutic intervention in acute myocardial infarction.

Adult↗
PubMed1981

The pathogenesis of small arterial lesions in nephrectomized rats by the administration of renin.

Intraperitoneal injection of purified hog renal renin produced a marked and sustained elevation of arterial pressure and lesions of the "fibrinoid necrosis" type in the small arteries and arterioles of the pancreas, heart and mesentery, but not of the brain, in bilaterally nephrectomized rats. Both the elevation of arterial pressure and the production of arterial lesions were completely prevented by pretreatment with oral SQ14225. Plasma renin clearance in bilaterally nephrectomized rats was markedly slower than that in sham-nephrectomized rats. Pre-treatment with oral SQ14225 did not affect renin clearance. It is suggested that sustained high blood pressure due to the sustained high plasma renin concentration in bilaterally nephrectomized rat was responsible for the production by renin of lesions of the fibrinoid necrosis type in the arteries.

Animals↗
PubMed1979

The vasotoxicity of the lysosomal contents from the renal cortex.

The retained proteins (fraction B: rich in renin) and the not retained proteins (fraction A: no renin activity) were obtained from the concanavalin A affinity column chromatography of the lysosomal contents from the hog renal cortex. Intraperitoneal injection of fraction A, B and highly purified renin produced angionecrosis of fibrinoid type of the small arteries and arterioles in the bilaterally nephrectomized rats. The angionecrosis producing activity (vasotoxicity) as well as vasopressor activity of fraction B were prevented completely by the oral administration of SQ14225. Although fraction A demonstrated no renin activity, intraperitoneal injection of fraction A produced gradual and transient elevation of blood pressure and fibrinoid necrosis which was milder and less consistent as compared with fraction B. The vasotoxicity as well as the transient vasopressor activity of fraction A were completely abolished also by the previous administration of oral SQ14225.

Animals↗
PubMed1978

Partial purification of renal lysosomal substances producing angionecrosis and increased vascular permeability.

The lysosomal contents of hog kidney cortex, which induce angionecrosis and/or an increase of vascular permeability, were obtained by differential centrifugation and osmotic shock treatment, and were purified by various chromatographic techniques and electrophoresis. The material producing an increase in vascular permeability of the rabbit skin was purified 600-fold over the homogenate; however, it showed practically no angionecrotic activity. Another substance producing angionecrosis without pressor activity was partially purified.

Animals↗