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Peçonha da cascavel Crotalus durissus terrificus prejudica a memória espacial e induz a morte neuronal no hipocampo, em ratos: estudos ' in vivo' e ' in vitro' / Crotalus durissus terrificus venom impairs spatial memory and induces neuronal death in rat hippocampus: \'in vivo\' and \'in vitro\' studiesDiego de Carvalho 25 February 2015 (has links)
A administração sistêmica da peçonha bruta da cascavel Sul-Americana (Crotalus durissus terrificus, Cdt) induz prejuízos de memória espacial em ratos, sugerindo a ocorrência de dano hipocampal. No presente estudo, foram utilizadas técnicas In vivo e In vitro, a fim de testar os potenciais efeitos centrais do veneno de Cdt e da crotoxina (CTX), principal neurotoxina componente da peçonha bruta da serpente. Foram investigados (1) efeitos comportamentais da administração sistêmica e intrahipocampal do veneno de Cdt e da CTX envolvendo diferentes versões do labirinto aquático de Morris; (2) a morte neuronal, o curso temporal e a ação protetora do soro anticrotálico à exposição de culturas organotípicas de hipocampo a doses crescentes (0,05-1 μg/mL) do veneno bruto de Cdt e de CTX, por meio da coloração fluorescente por Iodeto de propídeo (PI) (que reflete a morte neuronal); e (3) alguns dos possíveis mecanismos fisiopatológicos do envenenamento experimental em culturas de hipocampo utilizando o antagonista de receptores AMPA de glutamato, NBQX, à administração de 0,05 μg/mL do veneno bruto de Cdt, para avaliar a possível participação do glutamato e seus receptores na morte neuronal. A administração sistêmica e intrahipocampal do veneno bruto de cascavel em ratos promoveu marcados prejuízos de memória espacial de referência e operacional. Diferentemente, a CTX promoveu prejuízos comportamentais apenas quando a administração foi intrahipocampal. As culturas expostas ao veneno bruto apresentaram dano sobretudo nas células piramidais de CA1, enquanto as culturas incubadas com CTX não apresentaram danos. Essa seletividade em relação ao CA1 foi mais proeminente nas doses baixas. O soro anticrotálico preveniu a morte neuronal quando administrado até uma hora após a exposição do veneno. O NBQX preveniu parcialmente o dano em CA1 indicando a participação de receptores AMPA de glutamato na cascata de eventos que subjazem os danos a estas células causados pela peçonha bruta de Cdt. Estes achados podem contribuir para a tanto para elucidação dos mecanismos quanto para a conduta utilizada durante o envenenamento crotálico / Systemic administration of the South American rattlesnake (Crotalus durissus terrificus, Cdt) venom in rats permanently disrupts performance in hippocampus-dependent spatial memory tasks, thus indicating the occurrence of damage to this brain area. In vivo and In vitro approaches were employed in the present study to investigate the effects of the venom and its main compound, crotoxin (CTX). We investigated (1) behavioral effects after both systemic and intrahipocampal administration of either venom or CTX in rats on performance in different versions of the Morris\' water maze task; (2) neuronal death, evaluated by the intensity of propidium iodide (PI) fluorescence (neurotoxicity of the venom and of CTX, and the protection by the antivenom, on organotypic hippocampal slice cultures, were evaluated by comparing slices exposed to venom and (1) slices treated only with vehicle - negative control - and (2) slices incubated with 1 mM glutamate - positive control for maximal neuronal death), and the time course of neurotoxic effects of 0.05-1 μg/mL of crude Cdt venom and CTX, and the Brazilian anticrotalid serum on organotypic hippocampal slice cultures; and (3) provide an initial screening of the mechanisms underlying the venom action on cultured hippocampal slices, using the AMPA receptor antagonist NBQX and the crude venom at 0.5 μg/mL dose, to test whether the neuronal damage is mediated by glutamate following the experimental envenomation. Both systemic and intrahippocampal administration of Cdt venom induces permanent disruption of spatial reference memory and spatial working memory in rats. In contrast, CTX only promoted behavioral effects when administered intrahippocampally. Slices exposed to Cdt venom, but not to CTX, exhibited substantial neuronal damage. This effect was particularly prominent in the CA1 sub-field at lower concentrations of the venom. The antivenom prevented damage when applied until 1 hour after the exposure of the venom. The NBQX partially prevented damage to CA1, thus indicating that AMPA receptors play a role in the damage caused by the Cdt venom. These findings may be helpful in the elucidation and management of rattlesnake envenomation
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Purificação e caracterização de uma metaloprotease da peçonha da serpente Bothrops jararaca / Purification and characterization of a metalloproteinase from Bothrops jararaca snake venomSilva, Igor Rapp Ferreira da, 1981- 25 August 2018 (has links)
Orientador: Stephen Hyslop / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-25T14:01:57Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: O envenenamento causado por Bothrops jararaca pode resultar em dor local, edema, hemorragia e mionecrose, parcialmente causados por SVMPs. Neste trabalho, descrevemos a caracterização da BJ-PI2, uma metaloprotease da classe P-I da peçonha de B. jararaca e suas ações em tecidos locais. BJ-PI2 foi purificada por uma combinação cromatográfica de gel-filtração, troca aniônica e fase reversa em HPLC, e identificada por espectrometria de massas. As atividades coagulante e fibrin(ogen)olítica foram medidas por métodos convencionais. A atividade hemorrágica e as alterações na permeabilidade vascular foram examinadas em pele dorsal de ratos. A mionecrose e a atividade inflamatória foram avaliadas em músculo gastrocnêmio de camundongos. BJ-PI2, uma proteína de cadeia única com massa molecular de 23,08 kDa. Fragmentos trípticos da BJ-PI2 mostraram alta homologia com a SVMP insularinase A oriunda de Bothrops insularis, mas também com a bothrojaractivase, uma SVMP oriunda de B. jararaca; foi observada similaridade menor com a BJ-PI e jararafibrases II e IV isoladas de B. jararaca. A BJ-PI2 não coagula fibrinogênio nem plasma citratado de rato porém teve atividade ?- e ?-fibrinogenase (inibidas por EDTA e 1,10- fenantrolina mas não por PMSF) e atenuou a coagulação de plasma induzida pela recalcificação. BJ-PI2 tem atividade fibrinolítica. BJ-PI2 aumentou a permeabilidade vascular em pele dorsal de rato (atividade inibida por 1,10-fenantrolina). BJ-PI2 não provocou hemorragia ou mionecrose, contudo causou migração de células inflamatórias. Em contrapartida, a peçonha foi fortemente hemorrágica e mionecrótica porém causou pouca infiltração de células inflamatórias. Estes resultados indicam que a BJ-PI2 é uma SVMP não hemorrágica, não mionecrótica e não coagulante da classe PI que pode aumentar a permeabilidade vascular e a migração de células inflamatórias in vivo, mas não contribui com a hemorragia e a necrose induzidas pela peçonha / Abstract: Envenoming by Bothrops jararaca can result in local pain, edema, hemorrhage and necrosis, partially mediated by snake venom metalloproteinases (SVMPs). In this work, we describe the characterization of BJ-PI2, a P-I class SVMP from B. jararaca venom, and its local tissue actions. BJ-PI2 was purified by a combination of gel filtration, anion-exchange chromatography and reverse phase HPLC, and identified by mass spectrometry. Clotting and fibrin(ogen)olytic activities were assayed using conventional methods. Hemorrhagic activity and changes in vascular permeability were examined in rat dorsal skin. Myonecrosis and inflammatory activity were examined in mouse gastrocnemius muscle. BJ-PI2 was a 23.08 kDa single-chain polypeptide. Tryptic fragments showed highest homology with SVMP insularinase A from Bothrops insularis, but also with B. jararaca SVMP bothrojaractivase; less similarity was observed with B. jararaca SVMPs BJ-PI and jararafibrases II and IV. BJ-PI2 did not clot fibrinogen or rat citrated plasma but had ?- and ?-fibrinogenolytic activity (inhibited by EDTA and 1,10-phenanthroline but not by PMSF) and attenuated coagulation after plasma recalcification. BJ-PI2 had fibrinolytic activity. BJ-PI2 increased the vascular permeability of rat dorsal skin (inhibited by 1,10-phenanthroline). BJ-PI2 was not hemorrhagic or myonecrotic but caused migration of inflammatory cells. In contrast, venom was strongly hemorrhagic and myonecrotic but caused less infiltration of inflammatory cells. These results indicate that BJ-PI2 is a non-hemorrhagic, non-myonecrotic, non-coagulant P-I class SVMP that may enhance vascular permeability and inflammatory cell migration in vivo, but is not a major contributor to venom-induced hemorrhage and necrosis / Mestrado / Farmacologia / Mestre em Farmacologia
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Imunoterapia específica = efeitos sobre granulócitos de pacientes alérgicos ao veneno de Apis Mellifera / Specific immunotherapy : Effects on granulocytes from Apis Mellifera allergic patientsFerro, Karla Priscila Vieira, 1981- 19 August 2018 (has links)
Orientador: Ricardo de Lima Zollner / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T07:59:14Z (GMT). No. of bitstreams: 1
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Previous issue date: 2011 / Resumo: As reações alérgicas à ferroada de inseto resultam de resposta exacerbada do sistema imune, com produção de elevados níveis de anticorpos IgE alérgeno-específicos e padrão de citocinas Th2, envolvidas na diferenciação de linfócitos B específicos para aquele antígeno em células produtoras de IgE e recrutamento de células efetoras da resposta alérgica. Neste contexto, granulocitos são células efetoras importantes na fase tardia da resposta alérgica e estão envolvidos na patogênese de diferentes doenças. Eosinófilos e neutrófilos, especificamente, modulam a resposta imune por meio de diferentes mecanismos, como a secreçao de citocinas, quimiocinas e mediadores lipídicos. A IgE desempenha papel central na patogênese das doenças alérgicas, interagindo com dois receptores de membranas: alta afinidade FcsRI e baixa afinidade FcsRII (CD23). A ligação da IgE ao seu receptor em mastocitos e basófilos promove a liberação de mediadores inflamatórios, dentre eles, a histamina. A histamina além de induzir os sintomas agudos da reação alérgica, sustenta a reação inflamatória até a fase crônica, sendo estes efeitos mediados através da ativação de diferentes receptores (H1, H2, H3 e H4). Os fatores liberadores de histamina (HRF), particularmente, HRF-dependentes de IgE, induzem a liberação de histamina na fase tardia da resposta alérgica, permitindo a perpetuação dos eventos inflamatórios crônicos. Muitos estudos demonstram a eficácia da imunoterapia específica na dessensibilização e no desenvolvimento de tolerância em indivíduos com quadros graves de hipersensibilidade à ferroada de insetos, sobretudo da classe Hymenoptera. Com base nestas informações, foram objetivos do presente trabalho avaliar os efeitos modulatórios da imunoterapia sobre a expressão gênica dos receptores de histamina (H1, H2 e H4), HRF- IgE dependente e de fatores apoptóticos (Bcl-2 e BID) por RT-PCR, além da expressão gênica, através da técnica de PCR em tempo real de fatores de transcrição envolvidos na diferenciação de granulocitos como PU.1, C/EBPa, C/EBPpe GATA-1, receptores de alta (FcsRla e FcsRly) e baixa afinidade de IgE (CD23), cuja detecção protéica foi realizada por imunofluorescência e citometria de fluxo, respectivamente. Além disso, foram avaliados os níveis séricos de IgE específica, secreçao de RANTES e IL-8 nos sobrenadantes das culturas celulares e quantificação de granulocitos apoptóticos através da técnica de TÚNEL. Os granulocitos foram isolados de pacientes submetidos à imunoterapia específica ao veneno de abelha, em diferentes períodos do tratamento (Pré, 1, 3, 6, 12, 18 e 24 meses), após injeção subcutânea, e submetidas à cultura por 72 horas, com estimulo de 1 ng/mL veneno de abelha. Indivíduos não alérgicos foram estudados como grupo controle. De maneira geral, a imunoterapia específica ao veneno de abelha foi capaz de modular os elementos analisados, reduzindo significativamente a expressão dos mesmos ao final de 24 meses de tratamento. Não verificamos, apenas, modulação no número de granulocitos apoptóticos ao longo da imunoterapia. Nossos resultados inéditos fornecem informações adicionais sobre os efeitos da imunoterapia sobre granulocitos, reforçando as propriedades supressoras e tolerogênicas desta forma de tratamento / Abstract: Allergic reactions to insect stings results from a exacerbated response of the immune system, resulting in the production of high levels of allergen-specific IgE antibodies and Th2 cytokine pattern, which are involved in the differentiation process of B lymphocytes, specific for that antigen, into IgE producing cells and the recruitment of effector cells of allergic response. Eosinophils and neutrophils, specifically, modulate the immune response through different mechanisms, such as the secretion of cytokines, chemokines and lipid mediators. IgE plays a central role on allergic diseases pathogenesis, interacting with two membrane receptors: high affinity FcsRI and low affinity FcsRII (CD23). Biding of IgE with receptors on mast cells and eosinophils promotes the release of inflammatory mediators, among them, histamine. Histamine, besides inducing acute symptoms of allergic reaction, supports inflammatory response until its chronic stage; these effects are mediated through the activation of distinct receptors (H1, H2, H3 and H4). Histamine releasing factors (HRF), particularly, IgE dependent HRF, induce histamine release during the late phase of allergic response, allowing the perpetuation of chronic inflammatory events. In this context, many studies have demonstrated the efficacy of specific immunotherapy on desensitization and tolerance development in subjects with severe hypersensivity to insect stings, especially Hymenoptera. Based on all these information, the aim of the present study were to evaluate the modulating effects of immunotherapy on gene expression of histamine receptors (H1, H2 and H4), IgE dependent HRF and apoptotic factors (Bcl-2 and BID), through RT-PCR; in addition to gene expression, through real time PCR, transcriptional factors involved at granulocytes differentiation as of PU.1, C/EBPa, C/EBPp and GATA-1, and protein expression of high (FcsRIa e FcsRly)and low affinity (CD23) IgE receptors, assessed by immunofluorescence and flow cytometry, respectively. Serum levels of specific IgE were also assessed, along with RANTES and IL-8 secretion in cell culture supernatant and quantification of apoptotic granulocytes through TUNEL technique. Granulocytes were isolated from patients undergoing bee venom specific immunotherapy in different periods of treatment (Pre, 1, 3, 6, 12, 18 and 24 months), after subcutaneous injection, and cultured for 72 hours, with bee venom 1ng/ml_. Non allergic subjects were studied as control group. Overall, bee venom specific immunotherapy was able to modulate the analyzed elements, significantly reducing their expression at the end of 24 months of treatment. Modulation on the number of apoptotic granulocytes were not observed during immunotherapy. Our results provide additional information about the effects of immunotherapy over granulocytes, reinforcing the suppressor and tolerogenic properties of this treatment / Doutorado / Ciencias Basicas / Doutor em Clínica Médica
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A Homoeopathic drug proving of the venom of Bitis arietans arietansWright, Craig Douglas January 1999 (has links)
Dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Homoeopathy, Technikon Natal, 1999. / The purpose of this investigation was to determine the effects of the thirtieth centesimal (30 CH) potency of the venom of Bitis arietans arietans (the Puffadder) on healthy individuals in order to elucidate the totality of morbid symptoms produced by the drug, so that it may be prescribed according to the Law of Similars, as required by homoeopathic science. It was hypothesised that the 30 CH potency of Bitis arietans arietans would produce clearly observable symptoms and signs in healthy volunteers. / M
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The crotoxin complex, a high resolution electron microscopy study.Degn, Laura Lee, Degn, Laura Lee January 1988 (has links)
The crotoxin complex protein is the major neurotoxic component in the venom of the Brazilian rattlesnake, Crotalus durissus terrificus. The purified protein can be crystallized in the form of thin platelets (less than 500 Å thick) suitable for electron crystallography and image processing techniques. The unit cell dimensions of the crystal are a = 38.8 Å, b = 38.8 Å, c = 256 Å, and α = β = γ = 90°. These crystals can grow in layers. For a three-dimensional image reconstruction this necessitates the determination of the crystal thickness in order to combine information from low dose images of crystals of the same thickness. In the past, the highest resolution image (to 3.9 Å) recorded from a crotoxin complex crystal on the electron microscope was from a crystal embedded in glucose. However, since glucose cannot be removed in order to accurately determine the crystal thickness, a different embedding technique (amorphous ice embedding) and tried. It was determined that high resolution image information (to 3.9 Å) can be recorded from crotoxin complex crystals embedded in amorphous ice. Five images of crystals preserved in amorphous ice, all exhibiting resolution to at least 9 Å, were first processed by a global averaging method from which two-dimensional projection maps were calculated. These maps were not interpretable due to variations in the images as demonstrated by a second processing method. In the second processing method the images were divided into smaller areas, or patches, and these patches were averaged. The patchwork images produced from the second process indicate that there is variation across the original images. The most likely explanation for the variation is the bending, or lack of flatness, of the crystals on the grid. The determination of mass thickness of the crystals from optical density differences between the crystals and the carbon support in images of freeze-dried crystals was explored. It was found that this method could not determine the mass thickness of crotoxin complex crystals to within one layer (64 Å), but could clearly distinguish between one and three overlapping layers of freeze-dried purple membrane which was used as a test specimen.
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Studies on the action of selected venom components on the frog neuromuscular systemSantana De Sa, Sonia January 1975 (has links)
No description available.
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Sequenciamento do genoma da serpente Bothrops jararaca para caracterização da estrutura gênica de toxinas. / Genome sequencing of Bothrops jararaca snake for toxin gene structure characterization.Diego Dantas Almeida 07 December 2016 (has links)
A Bothrops jararaca é a serpente de maior importância médica no Brasil. Vários estudos foram realizados com o objetivo de caracterizar os componentes do veneno de serpentes, entretanto, a base molecular dos genomas das serpentes é pouco conhecida. Assim, foi realizado o sequenciamento e montagem do genoma da serpente Bothrops jararaca. Foram construídas bibliotecas tipo shotgun e mate-pair para realização de corridas de sequenciamento usando a tecnologia Illumina e sequências complementares foram obtidas em equipamento PACBIO RS II. Uma biblioteca de BACs também foi construída e 768 pools de 12 BACs foram sequenciados. Um grande conjunto de segmentos genômicos foi obtido e foi possível identificar genes de várias toxinas, entre elas SVMPs, SVSPs, BPPs, CRISPs e VEGF. Ainda foi possível depreender o contexto genômico de muitos destes genes e identificamos os principais elementos repetitivos genômicos. Estes achados são relevantes para o entendimento da função e evolução do sistema venenífero e podem servir de base para outros estudos futuramente. / The pit viper Bothrops jararaca is the most medically important snake in Brazil. Several studies were conducted in order to characterize the components of snake venom. However, the molecular basis of snake genomes is poorly known. Hence, it was carried out the sequencing and assembly of the Bothrops jararaca snake genome. Shotgun and mate-pair libraries were constructed to perform sequencing runs using Illumina technology and complementary sequences were obtained in PACBIO RS II equipment. A BAC library was also constructed and 768 pools of 12 BACs were sequenced. A large number of genomic segments was obtained. It was possible to identify genes of several toxins, including SVMPs, SVSPs, BPPs, CRISPs and VEGF. In addition, it was possible to infer the genomic context related to most of these genes and identify the main genomic repetitive elements. These findings are relevant for understanding the function and evolution of the venom system and it provides the basis for further studies.
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Studies in clinical toxinology in South Australia / Julian WhiteWhite, Julian January 1988 (has links)
Previous publications comprise main text of thesis / Includes bibliographical references / 1 v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D.)--University of Adelaide, Dept. of Pathology, 1988
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Mediação química da hiperagesia induzida pelos venenos de serpentes Bothrops jararaca e Bothrops asper e por uma miotoxina com atividade de fosfolipase A2 isolada do veneno de Bothrops asper / Chemical mediation of hyperalgesia induced by Bothrops jararaca and Bothrops asper snake venoms and by a phospholipase A2 miotoxin isolated from Bothrops asper venom.Chacur, Marucia 01 December 2000 (has links)
Os venenos do gênero Bothrops induzem efeitos locais caracterizados por hemorragia, necrose, edema e dor intensa. Apesar da importância clínica do fenômeno de dor, os estudos sobre os mecanismos envolvidos na gênese deste fenômeno são ainda escassos. Além disso, não existem dados sobre a capacidade do antiveneno em neutralizar este fenômeno. Neste trabalho foi investigada, a capacidade dos venenos de Bothrops jararaca, Bothrops asper e da miotoxina III (Fosfolipase A2, variante Asp 49), uma toxina isolada do veneno de Bothrops asper, em induzir hiperalgesia em ratos, a mediação química deste fenômeno e a capacidade dos antivenenos em neutralizar esta ação dos venenos. A possível correlação entre a hiperalgesia e a resposta edematogênica causada pelos venenos ou miotoxina foi também avaliada. O limiar de dor foi determinado antes e em diferentes tempos após a administração dos venenos ou toxina, empregando o teste de pressão de pata de rato. Para o estudo da resposta edematogênica, o aumento do volume das patas posteriores foi determinado por pletismografia. Os venenos e a toxina, administrados por via intraplantar, nas doses de 5µg (VBj), 15µg (VBa) ou 10µg (MIII), induziram hiperalgesia e edema, com respostas máxima na 1a (VBj, MIII) ou 2a (VBa) hora, não sendo mais detectadas na 24a hora. Para o estudo da neutralização, foram utilizados o antiveneno botrópico produzido no Instituto Butantan e o antiveneno polivalente produzido no Instituto Clodomiro Picado da Costa Rica, administrados por via endovenosa, 15 min. ou imediatamente antes ou 15 min. após a injeção dos venenos. O AVIB, quando injetado 15 min. antes do VBj, foi capaz de reverter a hiperalgesia induzida pelo veneno. Em relação ao edema, esta inibição foi observada quando o antiveneno foi administrado 15 min. ou imediatamente antes do VBj. Por outro lado, o AVCP não interferiu com a dor e o edema acarretados pelo VBa. Quando o VBj e o VBa foram incubados, in vitro, por 30 min., a 370C com os AV correspondentes, a hiperalgesia e o edema foram abolidos. Estes resultados indicam que a incapacidade do AVCP, quando administrado in vivo, de bloquear a hiperalgesia e o edema induzidos pelo VBa, não é consequência da ausência de anticorpos específicos no antiveneno, uma vez que estes efeitos foram inibidos quando o veneno foi pré-incubado com o antiveneno. Para avaliação da mediação química da hiperalgesia e do edema, os animais foram submetidos a tratamentos com inibidores de síntese, antagonistas de receptores, anticorpos ou drogas depletoras destes mediadores. Os resultados mostraram que o Hoe-140, dexametasona e NDGA inibem a hiperalgesia induzida pelo VBa, enquanto que apenas a prometazina interferiu com o edema causado pelo veneno. A hiperalgesia induzida pela MIII foi revertida pelo tratamento com prometazina, metisergida, Hoe-140, dexametasona e por NDGA, enquanto que o edema foi inibido apenas por prometazina e dexametasona. Estes dados sugerem que: a) a MIII é um importante componente do veneno para a geração de hiperalgesia, b) a bradicinina e os derivados da lipoxigenase são mediadores da dor acarretada pelo VBa e pela MIII, c) histamina e serotonina participam também da hiperalgesia induzida pela miotoxina e d) a histamina é mediador do edema induzido pelo VBa e pela MIII. Com relação à hiperalgesia induzida pelo VBj, somente o tratamento com Hoe-140 diminuiu este fenômeno, indicando a participação da bradicinina. Por outro lado, este tratamento não foi capaz de interferir com o edema induzido por este veneno. Cabe ressaltar que TEIXEIRA et al. (1994) demonstraram a participação de eicosanóides e PAF na hiperalgesia induzida pelo VBj. Os dados em conjunto sugerem ainda, dissociação entre os fenômenos de dor e edema acarretados por ambos os venenos e pela miotoxina. / Bothrops venoms cause pronounced local tissue-damage characterized by hemorrhage, myonecrosis, edema and pain. Venom-induced pain has been poorly investigated, despite its clinical relevance. Furthermore, the ability of antivenom to neutralize hyperalgesia induced by these venoms is not known. In the present study the hyperalgesia and edema induced by Bothrops jararaca (BjV) and Bothrops asper (BaV) venom and by myotoxin III-MIII (Asp49- phospholipase A2), a toxin isolated from BaV, were investigated. The chemical mediators involved in these phenomena and the ability of the antivenom to neutralize the hyperalgesia and edema induced by these venoms were also investigated. Pain threshold was assessed before and at several intervals after venom injection, using the rat paw pressure test. Edema of paw was measured phethysmographically at the same periods of time. The intraplantar injection of BjV (5µg/paw), BaV (15µg/paw) or MIII (10µg/paw) caused hyperalgesia and edema, whose peak were observed at the 1st (BjV, MIII) or 2nd (BaV) hours after venom/toxin administration, decreasing thereafter. For neutralization studies, the antivenoms produced either at Instituto Butantan from Brazil (AVIB) or Instituto Clodomiro Picado from Costa Rica (AVCP) were administered intravenously 15 min prior to, or immediately before, or 15 min after venoms injection. When the antivenom from Instituto Butantan was injected 15 min. before BjV, the hyperalgesia and edema were abolished. Furthermore, partial inhibition of edema was also observed when the antivenom was injected together with BjV. On the other hand, hyperalgesia and edema induced by BaV were not modified by AVCP. Incubation of BjV and BaV, for 30 min. at 37oC, with the antivenoms in vitro, abolished the hyperalgesia and edema. The inability of the in vivo treatment with antivenom in abolishing hyperalgesia and edema induced by BaV seems not to be related to the lack of neutralizing antibodies in antivenom, because neutralization was achieved in pre-incubation experiments. In order to investigate the chemical mediation of hyperalgesia and edema induced by the venoms or toxin, animals were treated with several drugs. Pretreatment with Hoe-140, dexamethasone and NDGA blocked the hyperalgesia induced by BaV, whereas only promethazine reduced the edema induced by this venom. The MIII-induced hyperalgesia was blocked by promethazine, methysergide, Hoe-140, dexamethasone and NDGA, whereas the edema was reduced only by promethazine and dexamethasone. These results suggest that: a) MIII may contribute to the BaV-induced hyperalgesia, b) bradykinin and leukotrienes mediate the BaV- and MIII-induced pain and MIII; c) histamine and serotonin also participate in the myotoxin-induced hyperalgesia and d) the edema induced by BaV and MIII is mediated by histamine. Pre-treatment of the animals with Hoe-140 abolished BjV-induced hyperalgesia, suggesting that bradykinin may mediate the venom-induced hyperalgesia. However, this treatment did not modify the BjV-induced edema. It is important to stress that previous studies have shown that BjV-induced hyperalgesia is mediated, at least partially, by eicosanoids and PAF (TEIXEIRA et al.,1994). The data presented herein also suggest that distinct mechanisms may be involved in the development of hyperalgesia and edema induced by both venoms and myotoxin III.
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Phänotypische und funktionelle Charakterisierung peripherer B-Zellen während WespengiftimmuntherapieRöver, Anne Constanze 25 May 2001 (has links)
Die Wespengiftallergie stellt eine typische allergische Sofortreaktion dar. Für diese IgE-vermittelten, pathologischen Immunreaktionen ist die spezifische Immuntherapie (IT) die einzige zur Zeit zur Verfügung stehende kausale Therapie. Die Wirkmechanismen sind trotz intensiver Bemühungen weiterhin nicht vollständig aufgeklärt. Als wichtigste These wird zur Zeit eine Verlagerung des pathologischen, TH2-dominierten Zytokinmilieus in Richtung "normales" TH1-Milieu diskutiert. Es wurde auch eine reduzierte Mediatorfreisetzung von Effektorzellen, eine verminderte Leukozytenproliferation, eine verminderte Endorganantwort und charakteristische Ig-Titer-Veränderungen mit initialem Anstieg und längerfristigem Abfall des sIgE und Anstieg des sIgG4 beschrieben. In der vorliegenden Arbeit wurde der Einfluß der IT auf periphere B-Zellen hinsichtlich ihrer Ig-Produktion und ihres Phänotyps untersucht. 15 Patienten mit systemischen Reaktionen nach Wespenstich, Nachweis von spezifischem IgE und positivem Hauttest, bei denen eine Schnell-Immuntherapie eingeleitet wurde, wurden vor Beginn der Therapie (Tag 1), am Tag ihrer Entlassung (Tag 6), also einen Tag, nachdem die Erhaltungsdosis von 100 µg erreicht wurde, und vor der 2. ambulanten Allergeninjektion am 26. Tag untersucht. Die Expression von CD5, CD23, CD32, CD40, CD54, CD86, CD95, HLA-I-ABC und HLA-II-DR wurde auf peripheren mononukleären Blutzellen durchflußzytometrisch bestimmt. Anti-CD19 FITC wurde als spezifischer B-Zellmarker benutzt. Die Serum-Titer des Gesamt-IgE, Wespengift-spezifischen IgE und Wespengift-spezifischen IgG4 wurden mittels ELISA bestimmt. Zur statistischen Auswertung wurde der Wilcoxontest für nicht-parametrische, verbundene Daten benutzt. Die Expression von CD54, CD5, CD32 und HLA-II-DR wurde durch die IT signifikant und die von CD23 tendentiell modifiziert. So war die Expression dieser Moleküle auf der Oberfläche peripherer B-Zellen am Tag 6 im Vergleich zum Ausgangswert vom Tag 1 reduziert. Am 26. Tag wurden wieder Werte auf der Höhe der Ausgangswerte vom Tag 1 gemessen. Dagegen veränderte sich die Expression von CD40, CD86, CD95 und HLA-I-ABC während der untersuchten Zeitpunkte nicht. Die Ig-Titer veränderten sich in der für die IT charakteristischen Weise. So stieg nach 3 Wochen der Gesamt-IgE-, sIgE- und sIgG4-Titer hochsignifikant an. Die Expression der untersuchten Oberflächenmoleküle ist als Indikator für Veränderungen der Aktivationslage und des funktionellen Status der Zellen während der IT zu interpretieren. So spricht die Reduktion der Expression von CD32, CD54 und HLA-II für eine verminderte Aktivierungslage der peripheren B-Zellen. Ferner deutet die Reduktion von CD5 und CD32 auf eine Anergie der B-Zellen hin. Durch die reduzierte Expression von CD23 und CD54 könnte die T-B-Zell-Interaktion verschlechtert werden, die für die Effektorfunktionen beider Zellen bedeutsam ist.Einen wesentlichen Beitrag zur Wirksamkeit der IT könnte auch die verminderte Expression des HLA-II leisten, da HLA-II für die Ag-Präsentation essentiell ist. In dieser Arbeit wurde gezeigt, daß die spezifische Immuntherapie einen Einfluß nicht nur auf die Ig-Produktion der B-Zellen hat, sondern auch auf deren Phänotyp. Dies könnte Hinweise auf bisher nicht bekannte Mechanismen bieten, die an der Wirksamkeit der IT beteiligt sind. / Wasp-venom allergy is a typical IgE-mediated allergic reaction. Specific immunotherapy (IT) is the only currently available causal therapy for IgE-mediated allergies. The mechanisms responsible for the efficacy of IT are still not fully understood. So far, the main focus of research has been on changes of T-helper cell (TH) cytokine production with a shift from TH2 to TH1 cytokines. Reduced mediator secretion from effector cells of allergic reactions, decreased leukocyte proliferation, lowered responsiveness of end organs and changes in immunoglobulin levels have been reported as well. The purpose of this study was to investigate the influence of IT on phenotype and Ig-production of B-lymphocytes. 15 venom allergic patients with a history of systemic reactions after a wasp sting and venom-specific skin test reactivity as well as serum IgE were investigated before VIT (day 1), one day after reaching maintenance dose of 100 µg (day 6) during inpatient rush VIT, and again on day 26 during continued outpatient maintenance therapy. Changes in the serum levels of total IgE, allergen-specific IgE (sIgE) and sIgG4 were measured by ELISA. Expression of CD5, CD23, CD32, CD40, CD54, CD86, CD95, HLA-I-ABC and HLA-II-DR on double labeled B cells was studied by flow cytometry of peripheral blood mononuclear cells. On day 6, cell surface expression of CD54, CD5, CD32 and HLA-II-DR was decreased significantly in intensity and numbers of positive cells, compared to day 1, while on day 26, expression of these molecules approached again baseline levels. Furthermore, a trend to decreased CD23 was noted on day 6. No changes were observed for CD40, CD86, CD95 and HLA-I-ABC. Levels of total IgE, sIgE and sIgG4 showed a significant increase after 26 days of VIT. These data show that initiation of rush VIT has profound effects on B-cell phenotype and Ig-production. Reduced expression of surface molecules can be interpreted as a reduction of activation status of B-cells as well as reduced ability to present antigen and to costimulate other leukocytes. B cells may thus be additional direct or indirect targets of high dose antigen therapy and contribute to the efficacy of IT.
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