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D M Flynn

Publications and source records attributed to D M Flynn.

58 records · Page 4Linked to original sources

Tachycardia-induced primate model of heart failure in cardiovascular drug discovery.

Congestive heart failure (CHF) is a complex, multifactoral disease involving genetic and environmental factors that represents a large unmet medical need. There are currently many animal models of CHF that have provided some insight into the etiology of this disease. However, due to the complex interactions of environmental and genetic components of this disease most animal models are somewhat limited. Nonhuman primates offer a unique opportunity to investigate the genetic aspects of this complex disease due to their close genetic and phenotypic similarity to humans. Here we describe a novel tachycardia-induced primate model of CHF characterized by depressed global function that progresses to a symptomatic stage consistent with clinical data. No animal model, including this one, can exactly mimic the clinical pathophysiology of CHF. However, this tachycardia-induced primate model of CHF has similarities to the dynamic state of CHF in humans and affords the opportunity to evaluate changes in gene expression using genomic and proteomic technologies throughout the progression of the disease.

Animals↗

Lymph isolated from a regional scald injury produces a negative inotropic effect in dogs.

Large surface-area burns in patients have been associated with a severe impairment in cardiac performance, as evidenced by a decline in cardiac output. The mechanisms responsible for this profound myocardial dysfunction are largely unknown. We investigated the effects of lymph isolated from the scalded hind limb of dogs on regional myocardial blood flow, coronary vascular reactivity, and contractile performance. Dogs were instrumented with ultrasonic dimension crystals in the myocardium supplied by the left anterior descending (LAD) and by the left circumflex (LCx) coronary arteries. After cannulating a hind limb lymphatic, lymph was infused directly into the LAD before and after a 10-second 100 degrees C hind limb scald. Scalding alone did not alter myocardial contractile performance in the LAD or LCx regions, coronary artery blood flow, or systemic hemodynamics. Interestingly, postburn lymph infused into the LAD resulted in a 38% decline in LAD zone segment shortening (p < 0.01 vs baseline) that lasted throughout the 5-hour observation period. In contrast, segment shortening in the (control) LCx region was unaffected by postburn lymph injections into the LAD. Regional myocardial blood flow (radiolabeled microspheres) in the LAD and LCx regions was unchanged after scald injury or intracoronary injection of postburn lymph. In addition, LAD coronary artery vascular reactivity to acetylcholine and nitroglycerin was also unaffected by the regional thermal injury or by injection of lymph into the LAD. These data suggest that a regional scald injury results in the production and release of a potent myocardial depressant factor(s) that produces a direct negative inotropic effect on the canine myocardium.

Animals↗