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M Rosolowsky

Publications and source records attributed to M Rosolowsky.

23 records · Page 2Linked to original sources
PubMed1987

Effect of blood coagulation and platelet aggregation on perfusable capillaries and arterioles in ischemic and nonischemic myocardium.

The aim of this study was to determine the effect of blood coagulation and platelet aggregation on the perfusability of arterioles (19-50 micron) and capillaries in subepicardial and subendocardial ischemic and nonischemic myocardium of anesthetized open-chest rabbits. Fluorescein isothiocynate-dextran (MW 150,000) was injected intravenously to label perfusable myocardial microvessels of rabbits that were subjected to 60 min of coronary artery occlusion. Fluorescent microscopy was used to identify the perfusable vessels and an alkaline phosphatase stain was employed to locate the total microvasculature of the heart. Stereological principles were utilized to determine various morphometric parameters. About 25% of the capillaries were incapable of being perfused but virtually all arterioles were perfusable in occluded myocardium of the control group. Essentially all capillaries and arterioles were perfusable in nonoccluded myocardium. Collagen infusion produced a perfusion defect in 14% of the capillaries and arterioles in nonoccluded myocardium and in 33% of the capillaries and arterioles in occluded myocardium. Heparin, prostaglandin E1 (PGE1), or PGE1 + heparin did not prevent the perfusion defect in capillaries of occluded myocardium. It is concluded that while promotion of blood coagulation and platelet aggregation was able to produce microvessel obstruction, these hemostatic mechanisms were not primarily responsible for the capillary obstruction observed during myocardial ischemia in the rabbit heart.

Alprostadil↗
PubMed1986

Quantitative morphometric determination of arteriolar and capillary perfusion within ischemic rabbit left ventricle.

The aim of this study was to identify the percentage of the capillary and arteriolar beds that was perfused at a given time or that was capable of being perfused within subepicardium and subendocardium of ischemic and nonischemic myocardium of anesthetized, open-chest rabbits. Fluorescein isothiocyanate-dextran (150,000 MW) was injected intravenously to label perfused microvessels of rabbits that were subjected to 60 min of coronary artery occlusion. Fluorescent microscopy was used to identify the perfused vessels and an alkaline phosphatase stain was employed to locate the total microvasculature. Stereological principles were utilized to determine various morphometric parameters. After 14 sec of dextran injection, approximately 66 +/- 2% (mean +/- SEM) of the capillaries and 65 +/- 5% of the arterioles (19-50 microns) were perfused within ischemic myocardium. Two minutes after dextran injection, 72 +/- 3% of the capillaries and 94 +/- 4% of the arterioles were perfused within the ischemic myocardium. In the nonischemic myocardium, 64 +/- 2% of the capillaries and 59 +/- 5% of the arterioles were perfused 14 sec after dextran injection, while 94 +/- 1% and 96 +/- 2% of the capillaries and arterioles, respectively, were perfused 2 min after dextran injection. It is concluded that a significant unperfused reserve of arterioles exists, but a significant portion of the capillary bed is incapable of being perfused within ischemic rabbit myocardium.

Animals↗
PubMedDate not supplied

Effect of dopamine and blockade of dopaminergic and adrenergic receptors on coronary blood flow in ischemic rabbit myocardium.

The effect of a broad dose range of dopamine on coronary blood flow was studied in rabbits with coronary artery occlusion. Dopaminergic and adrenergic receptor blockade was established to distinguish the mechanism of the dopamine-induced increase in coronary blood flow. Dopamine, 10, 100, or 1,000 micrograms/kg/min, was infused in the presence of dopaminergic, beta-, or alpha-adrenergic receptor blockade. Coronary blood flow, as measured by radiolabeled microspheres, and hemodynamic parameters were monitored in 60 anesthetized open-chest rabbits. Dopamine, 1,000 micrograms/kg/min, significantly increased coronary blood flow 157% in normal and 118% in occluded rabbit myocardium. Propranolol (2 mg/kg) prevented the dopamine-induced increases in coronary blood flow within occluded and nonoccluded myocardium. Practolol (2 mg/kg) blunted the coronary blood flow increases within occluded myocardium, but flow within normal myocardium remained significantly elevated. In animals given phenoxybenzamine (2 mg/kg), dopamine infusion produced significant blood pressure reductions along with no change in either occluded or nonoccluded coronary blood flow. Bulbocapnine (8 mg/kg), a dopamine receptor antagonist, did not block blood flow increases in normal myocardium, but prevented significant increases in blood flow within occluded myocardium. It can be concluded that direct or indirect vasodilator receptors (dopaminergic, beta 1-, and beta 2-adrenoceptors) must be stimulated and perfusion pressure must not fall in order for dopamine to produce increases of coronary blood flow within occluded myocardium.

Animals↗
PubMedDate not supplied

Effect of hypoxia and adenosine on the microvascular reserve in the rabbit heart.

This study was done to determine if the unperfused reserves of arterioles and capillaries in the rabbit heart can be utilized independently. Anesthetized, open-chest rabbits were subjected to control, hypoxia or adenosine treatment. The animals were given 100 mg/kg FITC-dextran and the hearts were removed and sectioned for analysis of perfused and total arteriolar and capillary morphology. The fluorescence was used to photograph the perfused microvessels and the slides were then stained for visualization of all microvessels. Standard morphometric techniques were used to determine total and perfused morphometric indices for these microvessels. Mean arteriolar total density (Na) was 4.4 arterioles/mm2 for control, adenosine, and hypoxia groups with approximately half (52%) of control arterioles perfused. Most of the adenosine (92%) and hypoxia (82%) group arterioles were perfused. Mean capillary total Na was 2143 capillaries/mm2 for all groups with approximately half (60%) of control capillaries being perfused. Nearly all capillaries were perfused during hypoxia (96%) while the percent perfused capillarity with adenosine (80%) was between those numbers for control and hypoxia groups despite completely perfused arterioles. The arteriolar and capillary reserves can be utilized independently as adenosine treatment resulted in complete arteriolar perfusion while not resulting in complete capillary perfusion.

Adenosine↗