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Biomedical subjects

K Kotoda

Publications and source records attributed to K Kotoda.

At least 19 recordsLinked to original sources
PubMed1989

[Studies on the prevention of postoperative thrombosis with a small dose of recombinant human tissue-type plasminogen activator].

In order to prevent the thrombosis on foreign materials after the cardiovascular operation, the effect of a small dose of recombinant human tissue-type plasminogen activator (t-PA) on the prosthetic material was examined. A polyvinyl-chloride tube was inserted into the left atrium of 12 rabbits. In six animals (group I), t-PA of 2.6 mg was injected into the right atrium, and no drug was used in other six animals (group II) as the control. Polyvinyl-chloride tube was removed from each animal 24 hours after implantation. In the medicated group, no thrombus was found in the tube, however, heavy thrombus formation was recognized around the tube in the control group. No clotting abnormality was shown in the medicated group. The results of this study demonstrate that t-PA will have a remarkable benefit in the prevention of thrombosis on the foreign substance in the cardiovascular system.

Animals↗
PubMed1985

Interaction of left ventricular contraction and aortic input impedance in experimental and clinical studies.

Implication of aortic input impedance and left ventricular coupling were investigated in three series of studies. In a clinical study, the ascending aortic flow velocity and pressure were simultaneously recorded from a multisensor catheter, and input impedance was calculated from 8 harmonics of aortic pressure and flow. Left ventricular wall stress was calculated from diameters and wall thickness of cineventriculogram and simultaneous recording of left ventricular pressure. In the experimental study, programmable artificial pulsatile pump was used to control pulsatile blood flow in dogs. The pressure-flow relationship in the arterial system had slightly convex curves toward the pressure axis with a critical turning pressure, so the arterial system had low output--high resistance and high output--low resistance characteristics. Therefore, the failed heart should inevitably eject the blood against stiffened vascular beds. Increased work load of the ventricle as expressed by sustained ventricular wall stress was determined mainly by the exaggerated late systolic pressure due to increased input resistance and increased low frequency pulsatile component of the input impedance. These findings are especially important for relieving additional work load of the ischemic heart, which have higher pressure wave reflection.

Animals↗
PubMed1983

Transseptal left-heart catheterization with Swan-Ganz flow-directed catheter.

Four cases of transseptal left-heart catheterization with the use of a Swan-Ganz flow-directed balloon-tipped catheter are reported. An 8.5F Teflon catheter covered with a Teflon tube (4 mm outer diameter) was inserted into the left atrium by the Brockenbrough technique. A Swan-Ganz catheter was then introduced into the left atrium through the Teflon tube and left-heart catheterization was performed. Unlike conventional methods, this method made it easier to insert a catheter into the left ventricle and also enabled advancement of the catheter into the aorta. Our experience suggests that this method is a valuable addition to cardiac catheterization laboratories.

Adolescent↗