Muscle Fiber Viability, a Novel Method for the Fast Detection of Ischemic Muscle Injury in Rats

Acute lower extremity ischemia is a limb- and life-threatening clinical problem. Rapid detection of the degree of injury is crucial, however at present there are no exact diagnostic tests available to achieve this purpose. Our goal was to examine a novel technique - which has the potential to accurately assess the degree of ischemic muscle injury within a short period of time - in a clinically relevant rodent model. Male Wistar rats were exposed to 4, 6, 8 and 9 hours of bilateral lower limb ischemia induced by the occlusion of the infrarenal aorta. Additional animals underwent 8 and 9 hours of ischemia followed by 2 hours of reperfusion to examine the effects of revascularization. Muscle samples were collected from the left anterior tibial muscle for viability assessment. The degree of muscle damage (muscle fiber viability) was assessed by morphometric evaluation of NADH-tetrazolium reductase reaction on frozen sections. Right hind limbs were perfusion-fixed with paraformaldehyde and glutaraldehyde for light and electron microscopic examinations. Muscle fiber viability decreased progressively over the time of ischemia, with significant differences found between the consecutive times. High correlation was detected between the length of ischemia and the values of muscle fiber viability. After reperfusion, viability showed significant reduction in the 8-hour-ischemia and 2-hour-reperfusion group compared to the 8-hour-ischemia-only group, and decreased further after 9 hours of ischemia and 2 hours of reperfusion. Light- and electron microscopic findings correlated strongly with the values of muscle fiber viability: lesser viability values represented higher degree of ultrastructural injury while similar viability results corresponded to similar morphological injury. Muscle fiber viability was capable of accurately determining the degree of muscle injury in our rat model. Our method might therefore be useful in clinical settings in the diagnostics of acute ischemic muscle injury

Artéria femoral profunda: uma opção como origem de fluxo para derivações infrageniculares Deep femoral artery: an option as inflow site in infragenicular bypasses

CONTEXTO: Na isquemia crítica, a artéria femoral profunda pode tornar-se a opção mais distal como origem de fluxo para derivações distais em casos de oclusão da origem da artéria femoral superficial associada a prega inguinal hostil. OBJETIVO:Avaliar, retrospectivamente, a artéria femoral profunda como doadora de fluxo para derivações infrageniculares. MÉTODOS: De 2000 a 2005, 129 derivações infrageniculares apresentaram anastomose proximal nas artérias femorais, comum (40), superficial (72) e profunda (17). O presente estudo teve como foco a artéria femoral profunda, e suas indicações foram: prega inguinal hostil (seis casos), limite da extensão do substituto (seis casos) e ambos os fatores (outros cinco casos). Foram abordadas a primeira e a segunda porção em 12 casos e a terceira porção em cinco casos. As cirurgias foram secundárias em 47% dos casos, e os substitutos utilizados foram veias do membro superior em 11 casos, safena interna em cinco e safena externa em um caso. RESULTADOS: No total dos enxertos (129), as estimativas de perviedade primária e salvamento do membro foram: 68,0% e 84,7%, respectivamente, com erro padrão (EP) aceitável (0,1) em 36 meses. Quando o grupo foi estratificado, as artérias femorais comum, superficial e profunda apresentaram resultados comparáveis de perviedade primária (63,3, 70,2 e 64,7%; p = 0,63) e salvamento do membro (83,1, 82,4 e 92,3%; p = 0,78). A perviedade dos enxertos com origem nas porções proximal e distal da artéria femoral profunda, bem como das cirurgias primárias e secundárias, foram comparáveis, sem diferença estatística significante (p = 0,89 e p = 0,77, respectivamente). CONCLUSÃO: A artéria femoral profunda mostrou ser acessível e efetiva como origem de fluxo de enxertos infrageniculares, com resultados satisfatórios de perviedade e salvamento do membro.<br>BACKGROUND: Deep femoral artery can be the most distal technical option as donor site in patients with critical limb ischemia presenting superficial artery occlusion and hostile groins. OBJECTIVE: To retrospectively assess the deep femoral artery as an inflow site for infragenicular bypass grafts. METHODS: From 2000 to 2005, 129 infragenicular bypass grafts with proximal anastomosis located in femoral arteries were performed. Forty were located in the common femoral artery (CFA), 72 in the superficial femoral artery (SFA) and 17 in the deep femoral artery (DFA). Indications for using the DFA as inflow were hostile groin (six cases), limited arterial substitute length (six cases) or both (five cases). Anastomosis site was located in the first or second portion in 12 cases, and in the third in five cases. The surgery was secondary in 47% of the cases, and the arterial substitutes used were arm veins (11), greater saphenous vein (five) and lesser saphenous vein (one). RESULTS: Primary patency and limb salvage rates were 68.0 and 84.7%, respectively, with acceptable standard error (0.1) in 36 months. The results of patency divided by inflow artery were similar (CFA, 63.3%; SFA, 70.2%; DFA 64.7%; p = 0.63), as well as limb salvage rates (CFA, 83.1%; SFA, 82.4%; DFA 92.3%; p = 0.78). Analyzing the deep femoral group, no difference of patency rates was observed when the anastomotic site was compared (proximal vs. distal portions of the DFA) or between patients with or without previous grafts. (p = 0.89 and 0.77, respectively). CONCLUSION: Deep femoral artery is a feasible and effective option as donor site for infragenicular bypass grafts, with satisfactory patency and limb salvage rates

Efficient embedding of complex networks to hyperbolic space via their Laplacian

design drawing, rendering of pedestrian bridge, 198