Biomedical subjects

K Kroll

Publications and source records attributed to K Kroll.

39 records · Page 3Linked to original sources

PubMed1979

Extracorporeal circulation system for coronary artery perfusion in the closed-chest dog.

An adjustable constant-flow coronary artery perfusion system has been developed for use in the anesthetized closed-chest dog. Coronary flow and perfusion pressure measurements are obtained over the entire autoregulatory range. Coronary flow was briefly diverted to a bypass cannula and then returned to its original level. Coronary vasodilatation resulted in a fall of perfusion pressure below its preocclusion value, but recovery of vascular tone was complete in about twice the time required during unrestricted reactive hyperemia. It is concluded that no flow debt repayment is required for the restoration of vascular tone after brief occlusions. In the measurements made with this system, intramyocardial pressure distribution is not influenced by thoracotomy, pericardotomy, or positive-pressure respiration, and surgical trauma is minimal.

Animals↗

PubMed1977

Haemodynamic side effects of antilymphocyte serum.

Haemodynamic side effects of antilymphocyte serum (ALS) have been studied in six dogs treated with equine anti-dog ALS. All animals responded with a severe but transient reduction of cardiac output and, in most cases, a drop in aortic pressure. This effect is best explained by a direct negative inotropic action followed by secondary vasoconstriction. An indirect effect of ALS by release of cardiotoxic substances from damaged blood cells seems to be a more probable explanation than a direct action of ALS on cardiac cell membranes.

Animals↗

PubMedDate not supplied

Regional myocardial blood volume and flow: first-pass MR imaging with polylysine-Gd-DTPA.

The authors investigated the utility of an intravascular magnetic resonance (MR) contrast agent, poly-L-lysine-gadolinium diethylenetriaminepentaacetic acid (DTPA), for differentiating acutely ischemic from normally perfused myocardium with first-pass MR imaging. Hypoperfused regions, identified with microspheres, on the first-pass images displayed significantly decreased signal intensities compared with normally perfused myocardium (P < .0007). Estimates of regional myocardial blood content, obtained by measuring the ratio of areas under the signal intensity-versus-time curves in tissue regions and the left ventricular chamber, averaged 0.12 mL/g +/- 0.04 (n = 35), compared with a value of 0.11 mL/g +/- 0.05 measured with radiolabeled albumin in the same tissue regions. To obtain MR estimates of regional myocardial blood flow, in situ calibration curves were used to transform first-pass intensity-time curves into content-time curves for analysis with a multiple-pathway, axially distributed model. Flow estimates, obtained by automated parameter optimization, averaged 1.2 mL/min/g +/- 0.5 (n = 29), compared with 1.3 mL/min/g +/- 0.3 obtained with tracer microspheres in the same tissue specimens at the same time. The results represent a combination of T1-weighted first-pass imaging, intravascular relaxation agents, and a spatially distributed perfusion model to obtain absolute regional myocardial blood flow and volume.

Animals↗