ABSTRACT
Comparisons between venoms from snakes kept under captivity or collected at the natural environment are of fundamental importance in order to obtain effective antivenoms to treat human victims of snakebites. In this study, we compared composition and biological activities of Bothrops atrox venom from snakes collected at Tapajós National Forest (Pará State, Brazil) or maintained for more than 10 years under captivity at Instituto Butantan herpetarium after have been collected mostly at Maranhão State, Brazil. Venoms from captive or wild snakes were similar except for small quantitative differences detected in peaks correspondent to phospholipases A2 (PLA2), snake venom metalloproteinases (SVMP) class PI and serine proteinases (SVSP), which did not correlate with fibrinolytic and coagulant activities (induced by PI-SVMPs and SVSPs). In both pools, the major toxic component corresponded to PIII-SVMPs, which were isolated and characterized. The characterization by mass spectrometry of both samples identified peptides that matched with a single PIII-SVMP cDNA characterized by transcriptomics, named Batroxrhagin. Sequence alignments show a strong similarity between Batroxrhagin and Jararhagin (96%). Batroxrhagin samples isolated from venoms of wild or captive snakes were not pro-coagulant, but inhibited collagen-induced platelet-aggregation, and induced hemorrhage and fibrin lysis with similar doses. Results suggest that in spite of environmental differences, venom variability was detected only among the less abundant components. In opposition, the most abundant toxin, which is a PIII-SVMP related to the key effects of the venom, is structurally conserved in the venoms. This observation is relevant for explaining the efficacy of antivenoms produced with venoms from captive snakes in human accidents inflicted at distinct natural environments.
Subject(s)
Bothrops/physiology , Crotalid Venoms/chemistry , Metalloproteases/chemistry , Amino Acid Sequence , Animals , Chromatography, High Pressure Liquid , Chromatography, Liquid , Crotalid Venoms/metabolism , Female , Male , Metalloproteases/metabolism , Molecular Sequence Data , RNA, Messenger/analysis , Tandem Mass SpectrometryABSTRACT
PURPOSE: To investigate the effects of percutaneous transluminal angioplasty on the vasa vasorum in dogs with experimentally created abdominal aortic stenoses. MATERIALS AND METHODS: Two stenoses were created in the abdominal aorta in each of 21 dogs. After 6 weeks, the more cephalic stenosis was dilated; the other stenosis served as an untreated control. Groups of three dogs were killed at 24 hours, 3 and 6 weeks, and 4, 8, 12, and 18 months after angioplasty. The aortae were studied by means of histologic examination, microangiography, scanning electron microscopy, and the Spalteholz technique. RESULTS: At nondilated stenoses, the vasa vasorum was interrupted in the outer adventitia and unchanged in the outer media. At dilated stenoses, the number of precapillary arterioles in the outer media progressively increased up to 8 months; thereafter, the number of precapillary arterioles began to decrease. At 18 months, the number was normal. CONCLUSION: Angioplasty brings about changes in the number of precapillary arterioles in the outer media of the aorta in our canine model of focal abdominal aortic stenosis.
Subject(s)
Angioplasty, Balloon , Aorta, Abdominal/pathology , Aortic Valve Stenosis/therapy , Vasa Vasorum/pathology , Animals , Aorta, Abdominal/diagnostic imaging , Aortic Valve Stenosis/diagnostic imaging , Aortic Valve Stenosis/pathology , Arterioles/pathology , Dogs , RadiographySubject(s)
Technology, Radiologic , Developing Countries , Equipment Design , European Union , PortugalABSTRACT
PURPOSE: Experimental stenoses were created in canine aortae to compare the effects of stent placement and balloon angioplasty on the vasa vasorum. MATERIALS AND METHODS: A balloon-expandable Palmaz stent was placed in the proximal stenosis, and angioplasty was performed in the distal stenosis in each of eight dogs. Two dogs were killed at 4, 8, 12, and 18 months, respectively. Specimens were studied by means of microangiography, histology, scanning electronic microscopy, and Spalteholz technique. RESULTS: At up to 12 months, there was proliferation of the vasa vasorum and a rich plexus formed in each of the animals at each treated site. More vasa vasorum were seen after stent placement than after angioplasty. The new vessels were mainly venules located in the media. At 18 months, there was regression of the venules and the vasa vasorum distribution returned to baseline. CONCLUSION: The authors conclude that the effects of stents on the vasa vasorum are temporary.
