Protective effect of leptin against ischemia-reperfusion injury in the rat small intestine

BACKGROUND: The small intestine is extremely sensitive to ischemia-reperfusion (I/R) injury and a range of microcirculatory disturbances which contribute to tissue damage. Previous studies have shown that leptin plays an important physiological role in the microvasculature. The aim of this study was to evaluate the protective effects of leptin in I/R – induced mucosal injury in the small intestine. METHODS: Forty rats were divided into 5 groups (n = 8). Group I was subjected to a sham operation. Following mesenteric ischemia in group II (control); physiologic saline 1 cm(3), in group III; leptin 100 μg/kg, and physiologic saline 1 cm(3), in group IV; N(G)-L-arginine methyl ester (L-NAME) 20 mg/kg, and physiologic saline 1 cm(3), in group V; leptin 100 μg/kg, L-NAME 20 mg/kg, and physiologic saline 1 cm(3 )were given intra-peritoneally. In these groups, an I/R procedure was performed by occlusion of the superior mesenteric artery for 45 min followed by 120 min reperfusion. After reperfusion, the small intestines were resected for malondialdehyde (MDA) and nitric oxide (NO) concentration and histopathologic properties. Mucosal lesions were scored between 0 and 5. Tissue MDA and NO concentration and histopathologic grades were compared statistically. RESULTS: Tissue MDA level significantly increased (P < 0.05), tissue NO level significantly decreased in group V animals, compared to group III animals respectively (P < 0.001). Histopathologically, intestinal injury significantly decreased in the leptin treated ischemic group. CONCLUSION: Leptin can be used safely in mesenteric occlusive diseases, since it induces NO formation and release in mesenteric vessels

Should the Law Governing Maritime Areas in the Arctic Adapt to Changing Climatic Circumstances?

The legal regime of the Arctic maritime areas has for a long time remained on the backburner of international norm creating activities. This can primarily be explained by the inhospitable climate which created natural barriers for human activities and imposed limits on the usefulness of the available technology.At present, however, climate change seems to be responsible for a marked heating up, not only of the mere physical environment of the Arctic, but also of the political tensions concerning the exact legal regime to be applied in the region.This chapter provides a close examination of the present-day legal status of the Arctic. Since almost all territorial claims have been settled in the area, the present contribution will only focus on the Arctic water areas with a special emphasis on navigation. Starting from what seems to have finally become a generally accepted legal cornerstone for appreciating the legal status of these waters, namely the 1982 United Nations Convention on the Law of the Sea, the chapter will first examine how climate change impacts on this legal regime. Subsequently, the vulnerability as well as the adaptive capacity of the 1982 Convention will be examined. Before drawing some conclusions, ways and means will be looked at for this existing legal system to better meet the new challenges that climate change poses for Arctic waters