Joseph L. Unthank

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Nonocclusive mesenteric ischemia (NOMI) is a poorly understood condition marked by progressive intestinal ischemia leading to infarction, sepsis, and death in a high proportion of patients. The mortality rate for this intestinal disorder remains high, even when the diagnosis is made early in the disease course. This paper presents a comprehensive review of(More)
The magnitude of shear stimulus has been shown to determine the level of growth factor expression in cell culture. However, little is known regarding what effect shear level has on specific arterial wall remodeling events in vivo. We have hypothesized that the rate of luminal diameter change and specific remodeling events within the arterial wall layers are(More)
Wall remodeling associated with rapid luminal enlargement of collateral mesenteric arteries in rats was investigated 1 and 4 weeks after creation of a collateral pathway by ligating three to four sequential arteries. Paired observations were made of inner diameters of collateral and normal arteries in the same animals. Arterial blood flow was measured at(More)
This study was designed to characterize in vivo arterial remodeling of male Wistar rat small mesenteric arteries exposed to varying levels of elevated blood flow in the presence of normal arterial pressure. Through a series of arterial ligations, respective ileal artery and second-order branch blood flows acutely increased approximately 36 and approximately(More)
Persistent elevation in shear stress within conduit or resistance arteries causes structural luminal expansion, which serves to normalize shear stress while maintaining increased flow to the downstream vasculature. Although it is known that this adaptation involves cellular proliferation and remodeling of the extracellular matrix, the specific cellular(More)
Recent clinical and animal studies have shown that collateral artery growth is impaired in the presence of vascular risk factors, including hypertension. Available evidence suggests that angiotensin-converting enzyme inhibitors (ACEI) promote collateral growth in both hypertensive humans and animals; however, the specific mechanisms are not established.(More)
Red blood cells labeled with the carbocyanine dyes, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) and 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO), were evaluated for use in making microvascular measurements in rat small intestine and spinotrapezius muscle. We determined the minimum concentration of each dye which produced(More)
The effect of maturation on collateral development of resistance arteries was investigated. Three to four sequential mesenteric arteries were ligated to create collateral pathways in anesthetized young (approximately 200 g) and mature (approximately 600 g) rats. Blood flow was similarly elevated in collaterals of young and mature animals. In vivo inner(More)
The technique to repeatedly observe exactly the same vessels in the rat intestine was used to investigate vascular compensation during the 1st wk after abrupt arterial ligation. A collateral-dependent tissue region was created by ligation of three to four sequential intestinal arteries. At the center of the collateral-dependent region, arterial pressure(More)
Previous studies have demonstrated endothelial and smooth muscle hyperplasia occur during arterial luminal expansion associated with elevation of arterial wall shear rates. The current study investigated whether remodeling induced by elevated wall shear would ultimately result in a vessel with intimal and medial cell densities and other wall characteristics(More)