Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Made available in DSpace on 2014-10-09T12:23:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:20Z (GMT). No. of bitstreams: 1 01047.pdf: 536137 bytes, checksum: 03a51eb43941329a5063f6f5a3acd271 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Biociencias, Universidade de Sao Paulo - IB/USP

Resumo: A integridade da perfusão sangüínea, em áreas previamente descoladas cirúrgica ou acidentalmente, ainda não foi esclarecida de modo satisfatório. Este detalhe é fundamental para o planejamento de retalhos comprometendo estas áreas. Este trabalho teve por objetivo avaliar, em ratos, a perfusão sangüínea em áreas previamente descoladas cirurgicamente, utilizando-se microesferas radioativas. Foram utilizados 48 ratos Wistar, divididos em quatro grupos. O tegumento cutâneo do flanco esquerdo foi descolado e, após 0, 7, 14 e 28 dias, teve sua perfusão sangüínea avaliada por meio de contagem de microesferas radioativas e das contagens dos vasos dérmicos e subdérmicos. Os resultados observados demonstraram maiores valores nos índices retalho/controle obtidos pelas contagens da radiação gama emitida pelas microesferas marcadas com tecnécio-99m, com diâmetro médio de 15 μm, após 7, 14 e 28 dias, quando comparados ao dia zero (p < 0,001, Teste de Kruskal-Wallis). Os índices obtidos pela contagem de vasos sangüíneos por meio de histologia, foram iguais nos quatro grupos. Concluiu-se que, por meio da técnica das microesferas radioativas, foi possível detectar-se a presença de perfusão sangüínea com 7, 14 e 28 dias após o descolamento prévio do tegumento cutâneo em relação ao músculo subjacente e que não houve diferença na contagem dos vasos dérmicos e subdérmicos nos quatro grupos, pelo método histológico. / Abstract: The integrity of blood perfusion in accidentally or surgically previously detached areas have not been fully explained. This is a fundamental detail for myocutaneous flap arrangement involving these areas. The objective of this work was to evaluate the blood perfusion in a previously surgically detached area, in rats, using radioactive microspheres. Forty-eight Wistar rats, divided into four groups (day 0, 7, 14 and 28) were used. The cutaneous tegument of the left flank was detached and after 0, 6, 14 and 28 days, its blood perfusion was evaluated by counting of radioactive microspheres and dermal and subdermal vessels. The results showed a significant difference in the mean count indexes evaluated by 15 μm diameter radioactive microspheres between the group of day 0 and the other groups, days 7, 14 and 28 (P<0,001). The vessels counting indexes were the same in all of the groups. It was concluded that there is blood perfusion at 7, 14 and 28 days after previous detachment of the cutaneous tegument and there is no significant difference in dermal and subdermal vessels count detected among the four groups. / Orientador: Fausto Viterbo / Coorientador: Beatriz Griva Viterbo / Mestre

Made available in DSpace on 2014-06-11T19:23:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2001Bitstream added on 2014-06-13T20:11:15Z : No. of bitstreams: 1 mellojunior_ejf_me_botfm.pdf: 990226 bytes, checksum: 1942b9c6092e2c3cce62055f3e57a32f (MD5) / A integridade da perfusão sangüínea, em áreas previamente descoladas cirúrgica ou acidentalmente, ainda não foi esclarecida de modo satisfatório. Este detalhe é fundamental para o planejamento de retalhos comprometendo estas áreas. Este trabalho teve por objetivo avaliar, em ratos, a perfusão sangüínea em áreas previamente descoladas cirurgicamente, utilizando-se microesferas radioativas. Foram utilizados 48 ratos Wistar, divididos em quatro grupos. O tegumento cutâneo do flanco esquerdo foi descolado e, após 0, 7, 14 e 28 dias, teve sua perfusão sangüínea avaliada por meio de contagem de microesferas radioativas e das contagens dos vasos dérmicos e subdérmicos. Os resultados observados demonstraram maiores valores nos índices retalho/controle obtidos pelas contagens da radiação gama emitida pelas microesferas marcadas com tecnécio-99m, com diâmetro médio de 15 μm, após 7, 14 e 28 dias, quando comparados ao dia zero (p < 0,001, Teste de Kruskal-Wallis). Os índices obtidos pela contagem de vasos sangüíneos por meio de histologia, foram iguais nos quatro grupos. Concluiu-se que, por meio da técnica das microesferas radioativas, foi possível detectar-se a presença de perfusão sangüínea com 7, 14 e 28 dias após o descolamento prévio do tegumento cutâneo em relação ao músculo subjacente e que não houve diferença na contagem dos vasos dérmicos e subdérmicos nos quatro grupos, pelo método histológico. / The integrity of blood perfusion in accidentally or surgically previously detached areas have not been fully explained. This is a fundamental detail for myocutaneous flap arrangement involving these areas. The objective of this work was to evaluate the blood perfusion in a previously surgically detached area, in rats, using radioactive microspheres. Forty-eight Wistar rats, divided into four groups (day 0, 7, 14 and 28) were used. The cutaneous tegument of the left flank was detached and after 0, 6, 14 and 28 days, its blood perfusion was evaluated by counting of radioactive microspheres and dermal and subdermal vessels. The results showed a significant difference in the mean count indexes evaluated by 15 μm diameter radioactive microspheres between the group of day 0 and the other groups, days 7, 14 and 28 (P<0,001). The vessels counting indexes were the same in all of the groups. It was concluded that there is blood perfusion at 7, 14 and 28 days after previous detachment of the cutaneous tegument and there is no significant difference in dermal and subdermal vessels count detected among the four groups.

Made available in DSpace on 2014-10-09T12:23:39Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:20Z (GMT). No. of bitstreams: 1 01047.pdf: 536137 bytes, checksum: 03a51eb43941329a5063f6f5a3acd271 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Biociencias, Universidade de Sao Paulo - IB/USP

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / PeÃonhas de Hymenoptera, particularmente das famÃlias Apidae (abelhas) e Vespidae (vespas), sÃo uma rica fonte de peptÃdeos e proteÃnas com atividades biolÃgicas. A espÃcie Polybia Paulista à uma vespa social neotropical muito agressiva e endÃmica no Sudeste do Brasil. O objetivo deste trabalho foi estudar os efeitos renais e vasculares induzidos pelo veneno da Polybia paulista (VPp). Foram utilizados ratos (n = 4) machos Wistar pesando entre 250 e 300g, cujos rins foram isolados e perfundidos com SoluÃÃo de Krebs-Henseleit modificada contendo 6g% de albumina bovina previamente dialisada. A menor concentraÃÃo (1Âg/mL) nÃo apresentou efeito nos parÃmetros avaliados. PorÃm, a concentraÃÃo de 3Âg/mL produziu um aumentou na pressÃo de perfusÃo renal (PP), na resistÃncia vascular renal (RVR), no fluxo urinÃrio (FU) e no ritmo de filtraÃÃo glomerular (RFG). Foi tambÃm observada uma reduÃÃo aos 60â no percentual de transporte tubular de sÃdio (% TNa+). Na avaliaÃÃo histolÃgica do rim perfundido com VPp foi observado depÃsito de proteÃnas nos tÃbulos renais e nos espaÃos urinÃrios, bem como regiÃes focais de necrose/apoptose. A citotoxidade do veneno da Polybia paulista em cultura de cÃlulas MDCK foi analisada atravÃs do ensaio colorimÃtrico com sal de tetrazolium (MTT). O veneno promoveu um efeito citotÃxico dependente de concentraÃÃo com um valor de IC50 de 25.81Âg/mL. TambÃm foram mensurados os nÃveis de lactato desidrogenase (LDH) e observado um aumento significativo nas maiores concentraÃÃes estudadas. No estudo em leito mesentÃrico a pressÃo de perfusÃo foi mensurada atravÃs de um transdutor de pressÃo. O efeito vascular do VPp (3Âg/mL) nÃo alterou a pressÃo basal, na concentraÃÃo de 10Âg/mL, foi observado um aumento pressÃrico discreto e na concentraÃÃo de 100 Âg/mL, foi observado um acentuado aumento na pressÃo de perfusÃo basal. O efeito vasoconstritor observado no estudo renal e em leito mesentÃrico, tambÃm foi demonstrado no protocolo de anel de aorta, sendo observado de maneira concentraÃÃo dependente, um aumento do tÃnus basal apÃs a infusÃo do VPp. Em conclusÃo, o VPp causou nefrotoxidade, sugestivo de uma aÃÃo direta com morte celular em cÃlulas do tÃbulo renal por necrose. O efeito vascular contrÃtil que envolve influxo de cÃlcio atravÃs de canais operados por voltagem, provavelmente à mediado pela ativaÃÃo de receptores alfa adrenÃgicos.

University of Macau / Institute of Chinese Medical Sciences

Indiana University-Purdue University Indianapolis (IUPUI) / Neurofibromatosis type 1 (NF1) is a genetic disorder resulting from mutations in the tumor suppressor gene NF1. NF1 encodes the protein neurofibromin, which functions to negatively regulate p21Ras signaling. NF1 has a wide range of clinical manifestations, including vascular disease, which is characterized by neointima formation and subsequent vessel occlusion. Despite numerous clinical observations of NF1 vasculopathy, the pathogenesis of vascular lesion formation remains unclear. To determine the consequence of Nf1 haploinsufficiency in vascular disease, we generated an in vivo model for dissecting vascular lesion formation. In response to mechanical arterial injury, Nf1+/- mice have significantly enhanced neointima formation characterized by an accumulation of vascular smooth muscle cells (VSMCs) and excessive cellular proliferation and Ras activation. Further, using the pharmacological antagonist, imatinib mesylate, we identified that neointima formation in Nf1+/- mice was directly dependent on Ras signaling through either the platelet derived growth factor β receptor (PDGF-βR) and/or the C-kit receptor activation. These observations identify a molecular mechanism of neointima formation given that our group has previously demonstrated that Nf1+/- VSMCs have hyperactive Ras signaling through PDGF-βR activation and Nf1+/- bone marrow derived cells (BMDCs) have increased recruitment and survival in response to C-kit activation compared to WT controls. In order to dissect the cellular contribution to neointima formation, we utilized cre/lox technology and adoptive hematopoietic stem cell transfer techniques to genetically delete one allele of Nf1 in endothelial cells, VSMCs or BMDCs individually to test which cell lineage is predominant in NF1 vasculopathy. Surprisingly, in response to carotid artery injury, heterozygous inactivation of Nf1 in BMDCs alone was necessary and sufficient for neointima formation. Specifically, Nf1 haploinsufficiency in BMDCs resulted in an infiltration of macrophages into the neointima, providing evidence of “vascular inflammation” as factor in NF1 vasculopathy. Further, we demonstrate for the first time that NF1 patients have evidence of chronic inflammation determined by increased concentrations of circulating monocytes and pro-inflammatory cytokines. In sum, we provide genetic and cellular evidence of vascular inflammation in NF1 patients and Nf1+/- mice and provide a framework for understanding the pathogenesis of NF1 vasculopathy and potential therapeutic and diagnostic interventions.

<p> Peroxynitrite is formed in blood vessels upon reaction of superoxide anion with nitric oxide (NO). It can oxidize proteins and thiols and nitrosylate free or protein bound thiols and tyrosine residues, thereby producing vascular dysfunction. Peroxynitrite therefore, may contribute to hypertension and cardiovascular diseases. We investigated the in vitro effects of commercially available peroxynitrite. De-endothelialized rings from the left descending coronary artery of pig were treated with peroxynitrite for 30 min, washed and then contracted with cyclopiazonic acid (CPA) or by membrane depolarization with KCl. Tissues pre-treated with peroxynitrite showed inhibition of the CPA-induced contraction with an IC50 of ≈100 uM but there was no effect on KCl-induced contraction. Peroxynitrite is stable only at alkaline pH and it may decompose to form superoxide and NO. However, including superoxide dismutase + catalase along with peroxynitrite did not change its effect.</p> <p> Next, we used the same protocol to compare the effects of peroxynitrite and NO generating agents: 3-morpholino sydnonimine (SIN-1), s-nitroso-N-acetylpenicilliamine (SNAP), sodium nitroprusside (SNP) and spermine nonoate. The effectiveness of these agents to inhibit the CPA-induced contraction was SNAP > spermine nonoate ≥ SIN-1 > SNP. SNAP was the most effective in inhibiting the KCl-induced contraction with spermine nononoate being less effective and SIN-1 and SNP not producing any significant inhibition. We further investigated the effect of SNAP. Catalase, superoxide dismutase or CPTIO (a NO scavenger) did not prevent the effects of SNAP on the KCl or the CPA-induced contractions. The guanylate cyclase inhibitor ODQ, partially reversed the effects of only low concentrations of SNAP. Thus, pretreatment with NO generating agents such as SNAP and spermine NONOate appear to be more effective in inhibiting the contraction of the pig coronary artery than with peroxynitrite or the peroxynitrite generating agent SIN-1. Since SIN-1, SNAP, SNP and NONOates produce different amounts of peroxynitrite, nitric oxide and S-nitrosylation products, their effects may be used to delineate the molecular basis of the actions of peroxynitrite and NO on the arterial function.</p> / Thesis / Master of Science (MSc)