RESUMO
BACKGROUND: Amphibian defence against predators and microorganisms is directly related to cutaneous glands that produce a huge number of different toxins. These glands are distributed throughout the body but can form accumulations in specific regions. When grouped in low numbers, poison glands form structures similar to warts, quite common in the dorsal skin of bufonids (toads). When accumulated in large numbers, the glands constitute protuberant structures known as macroglands, among which the parotoids are the most common ones. This work aimed at the morphological and biochemical characterization of the poison glands composing different glandular accumulations in four species of toads belonging to group Rhinella marina (R. icterica, R. marina, R. schneideri and R. jimi). These species constitute a good model since they possess other glandular accumulations together with the dorsal warts and the parotoids and inhabit environments with different degrees of water availability. RESULTS: We have observed that the toads skin has three types of poison glands that can be differentiated from each other through the morphology and the chemical content of their secretion product. The distribution of these different glands throughout the body is peculiar to each toad species, except for the parotoids and the other macroglands, which are composed of an exclusive gland type that is usually different from that composing the dorsal warts. Each type of poison gland presents histochemical and biochemical peculiarities, mainly regarding protein components. CONCLUSIONS: The distribution, morphology and chemical composition of the different types of poison glands, indicate that they may have different defensive functions in each toad species.
RESUMO
Patients bitten by snakes consistently manifest a bleeding tendency, in which thrombocytopenia, consumption coagulopathy, mucous bleeding, and, more rarely, thrombotic microangiopathy, are observed. Von Willebrand factor (VWF) is required for primary hemostasis, and some venom proteins, such as botrocetin (a C-type lectin-like protein) and snake venom metalloproteinases (SVMP), disturb the normal interaction between platelets and VWF, possibly contributing to snakebite-induced bleedings. To understand the relationship among plasma VWF, platelets, botrocetin and SVMP from Bothrops jararaca snake venom (BjV) in the development of thrombocytopenia, we used (a) Wistar rats injected s.c. with BjV preincubated with anti-botrocetin antibodies (ABA) and/or Na2-EDTA (a SVMP inhibitor), and (b) VWF knockout mice (Vwf-/-) injected with BjV. Under all conditions, BjV induced a rapid and intense thrombocytopenia. In rats, BjV alone reduced the levels of VWF:Ag, VWF:CB, high molecular weight multimers of VWF, ADAMTS13 activity, and factor VIII. Moreover, VWF:Ag levels in rats that received BjV preincubated with Na2-EDTA and/or ABA tended to recover faster. In mice, BjV caused thrombocytopenia in both Vwf-/- and C57BL/6 (background control) strains, and VWF:Ag levels tended to decrease in C57BL/6, demonstrating that thrombocytopenia was independent of the presence of plasma VWF. These findings showed that botrocetin present in BjV failed to affect the extent or the time course of thrombocytopenia induced by envenomation, but it contributed to decrease the levels and function of plasma VWF. Thus, VWF alterations during B. jararaca envenomation are an ancillary event, and not the main mechanism leading to decreased platelet counts.
Assuntos
Bothrops/metabolismo , Venenos de Crotalídeos/toxicidade , Mordeduras de Serpentes/complicações , Venenos de Serpentes/toxicidade , Trombocitopenia/etiologia , Trombocitopenia/metabolismo , Fator de von Willebrand/metabolismo , Animais , Plaquetas/metabolismo , Venenos de Crotalídeos/metabolismo , Feminino , Humanos , Masculino , Metaloproteases/metabolismo , Metaloproteases/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ratos , Ratos Wistar , Venenos de Serpentes/enzimologia , Venenos de Serpentes/metabolismo , Trombocitopenia/sangue , Trombocitopenia/genética , Fator de von Willebrand/genéticaRESUMO
Studies of scorpion venoms have used different venom drying methods: lyophilization, desiccation, lyophilization after mixing with 0.9% saline or purified water and centrifugation. The aim of this study was to see if these different approaches cause some alteration in the composition of the venom or interfere with its biological effects. Mice were injected (i.p.) with T. serrulatus scorpion venom in the liquid form (G-liq) or dried by different methods (lyophilized - G-lyo; centrifuged and the supernatant lyophilized - G-cen; desiccated - G-des), and observed regarding the occurrence of the symptoms respiratory difficulty, convulsion and death. The occurrence of seizures, although occurring in all groups and with the various doses used, did not prove to be effective to determine differences between the different handling techniques. Respiratory distress appeared to be useful in analyzing differences between groups, where this effect was less pronounced in the G-liq and G-des groups. In general, death occurred in a certain proportion with increasing dose for all groups. G-liq and G-des seemed to be more "active" at lower doses and G-cen and G-lyo at higher doses. The electrophoretic and chromatographic profile demonstrated main differences between G-liq and the dried groups. In the electrophoretic profile, the liquid venom showed bands of proteins of higher concentration and greater number of major bands and the three dried venom had the lowest number of protein bands. The HPLC profile and densitometry of the electrophoretic profiles showed some differences that may be associated with different protein conformation/aggregation. Our data indicated that lyophilization is the most suitable method for processing T. serrulatus scorpion venom after extraction.
Assuntos
Venenos de Escorpião/química , Venenos de Escorpião/toxicidade , Animais , Cromatografia Líquida de Alta Pressão , Dessecação , Eletroforese em Gel de Poliacrilamida , Liofilização , Masculino , Camundongos , EscorpiõesRESUMO
Loxosceles venom is a potential source of bioactive molecules which may be transformed into antimicrobial products against multi-resistant bacteria. Here, it was investigated whether Loxosceles gaucho spider had any influence on the proliferation, enzyme release and biofilm formation of a Pseudomonas aeruginosa strain resistant to two different classes of antibiotic. The results demonstrated that L. gaucho whole venom has no influence on P. aeruginosa proliferation. However, it increases P. aeruginosa production of gelatinase, caseinase and biofilm formation. The same effects were noted when P. aeruginosa was exposed to a L. gaucho venom molecular fraction with mass lower than 1â¯kDa. Separation of this molecular fraction into different subsets by RP-HPLC demonstrated that, among the molecules with the ability to increase the production of enzymes and biofilm formation, there are some with antimicrobial activities whose effects are not observed in the whole venom. In summary, the results obtained herein indicate that L. gaucho venom has a variety of low molecular mass bioactive components that influence the mechanisms of virulence of P. aeruginosa in different ways.
Assuntos
Diester Fosfórico Hidrolases/química , Diester Fosfórico Hidrolases/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Venenos de Aranha/química , Venenos de Aranha/farmacologia , Virulência/efeitos dos fármacos , Animais , Biofilmes/efeitos dos fármacos , Gelatinases/metabolismo , Metaloendopeptidases/metabolismo , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , AranhasRESUMO
There are a great number of studies about Brazilian scorpions. However, little is known about the venom of scorpions of northern Brazil, mainly about Tityus obscurus, which is responsible for the most number of accidents in the Amazon. Thus, this study aimed to evaluate some pharmacological effects of T. obscurus venom in rats and mice. In rats, the venom (10 mg/kg i.p.) caused hemorrhagic patches in the lung parenchyma but did not lead to pulmonary edema. There was a decrease in general activity, observed in the activity box after venom injection. The venom did not induce changes in the occurrence and intensity of experimentally induced convulsions, nor did it cause hippocampal neuronal loss. In mice, the LD50 obtained was 3.13 mg/kg (i.p.). Different doses of the venom (0.2; 1; 5; 10; 15 µg/30 µL per hind paw) induced edematogenic and moderate nociceptive activity in mice. The Tiyus serrulatus venom used as comparison caused more intense symptomatology in mice. Comparing to the venom of other Tityus scorpions of medical importance, that have convulsant and intense nociceptive effects and cause lung edema, as described in the literature, we can conclude that the venom of T. obscurus probably has different characteristics.
Assuntos
Venenos de Escorpião/toxicidade , Animais , Comportamento Animal/efeitos dos fármacos , Brasil , Hipocampo/efeitos dos fármacos , Dose Letal Mediana , Pulmão/efeitos dos fármacos , Camundongos , Ratos , Ratos Wistar , Convulsões/induzido quimicamente , Especificidade da EspécieRESUMO
The ability of IgG(T) and IgGa subclasses--isolated by liquid chromatography from equine arachnidic antivenom (AAV)-to neutralize toxic activities of Loxosceles gaucho, Phoneutria nigriventer and Tityus serrulatus venoms as well as to remove venom toxins from circulation was investigated. These subclasses showed similar antibody titers against L. gaucho, P. nigriventer and T. serrulatus venoms, and by immunoblotting few differences were observed in the recognition pattern of venom antigens. IgG(T) and IgGa neutralized 100% lethality induced by L. gaucho and 50% of P. nigriventer venom, but IgGa failed to neutralize T. serrulatus venom, in contrast to IgG(T). Both subclasses neutralized local reactions and dermonecrosis induced by L. gaucho venom in rabbits. In mice, IgG(T) and IgGa partially neutralized the edematogenic activity induced by P. nigriventer and T. serrulatus venoms, but only IgG(T) neutralized (ca. 81%) the nociceptive activity induced by T. serrulatus venom. Both subclasses failed to neutralize nociceptive activity induced by P. nigriventer venom. IgG(T) reduced the serum venom levels of animals injected with L. gaucho, P. nigriventer or T. serrulatus venoms, while IgGa solely reduced L. gaucho and P. nigriventer venoms levels. Our results demostrate that IgG(T) and IgGa subclasses neutralize toxic activities induced by P. nigriventer, T. serrulatus and L. gaucho venoms with different efficacies, as well as depurate these venoms from circulation.
Assuntos
Antivenenos/farmacologia , Imunoglobulina G/farmacologia , Venenos de Escorpião/antagonistas & inibidores , Venenos de Aranha/antagonistas & inibidores , Aranhas/química , Animais , Antivenenos/química , Cromatografia Líquida , Cavalos/imunologia , Imunoglobulina G/isolamento & purificação , Camundongos , Diester Fosfórico Hidrolases/imunologia , Diester Fosfórico Hidrolases/toxicidade , Venenos de Escorpião/imunologia , Venenos de Escorpião/toxicidade , Venenos de Aranha/imunologia , Venenos de Aranha/toxicidade , Aranhas/metabolismoRESUMO
Patients bitten by snakes consistently manifest a bleeding tendency, in which thrombocytopenia, consumption coagulopathy, mucous bleeding, and, more rarely, thrombotic microangiopathy, are observed. Von Willebrand factor (VWF) is required for primary hemostasis, and some venom proteins, such as botrocetin (a C-type lectin-like protein) and snake venom metalloproteinases (SVMP), disturb the normal interaction between platelets and VWF, possibly contributing to snakebite-induced bleedings. To understand the relationship among plasma VWF, platelets, botrocetin and SVMP from Bothrops jararaca snake venom (BjV) in the development of thrombocytopenia, we used (a) Wistar rats injected s.c. with BjV preincubated with anti-botrocetin antibodies (ABA) and/or Na2-EDTA (a SVMP inhibitor), and (b) VWF knockout mice (Vwf-/-) injected with BjV. Under all conditions, BjV induced a rapid and intense thrombocytopenia. In rats, BjV alone reduced the levels of VWF:Ag, VWF:CB, high molecular weight multimers of VWF, ADAMTS13 activity, and factor VIII. Moreover, VWF:Ag levels in rats that received BjV preincubated with Na2-EDTA and/or ABA tended to recover faster. In mice, BjV caused thrombocytopenia in both Vwf-/- and C57BL/6 (background control) strains, and VWF:Ag levels tended to decrease in C57BL/6, demonstrating that thrombocytopenia was independent of the presence of plasma VWF. These findings showed that botrocetin present in BjV failed to affect the extent or the time course of thrombocytopenia induced by envenomation, but it contributed to decrease the levels and function of plasma VWF. Thus, VWF alterations during B. jararaca envenomation are an ancillary event, and not the main mechanism leading to decreased platelet counts.
RESUMO
Loxosceles spiders have a wide distribution in the temperate and tropical regions of the world. Loxoscelism is characterized by necrotic skin ulceration at the bite site and, less commonly, a systemic illness that may be fatal. The purpose of this study was to characterize and compare aspects of the major medically important Loxosceles spider venoms in a standardized manner, particularly considering their neutralization by two Brazilian antivenoms. By SDS-PAGE (12% acrylamide), Loxosceles deserta, Loxosceles gaucho, Loxosceles intermedia, Loxosceles laeta and Loxosceles reclusa venoms had similar electrophoretic profiles, with the major protein bands of 32-35 kDa. All venoms exhibited gelatinolytic, caseinolytic and fibrinogenolytic activities in vitro with a large array of proteases, mainly between 18.1 and 31.8 kDa. Most of these enzymes were metalloproteases as this activity was abolished by 1,10-phenanthroline. Hyaluronidase activity was detected in a protein band of approximately 44 kDa in all venoms. Sphingomyelinase activity was demonstrated in all five venoms. Antigenic cross-reactivity, by Western blotting, was also observed among all venoms studied using commercial equine antivenoms produced in Brazil (Institute Butantan and CPPI). These antivenoms recognized mainly components between 25 and 40 kDa in all venoms with several minor components of >89 kDa. Strong cross-reactivity was also seen among all venoms through the ELISA technique (titre range: 64,000-512,000). All venoms (5 microg doses) induced a similar local reaction when injected intradermally into the flank of rabbits, demonstrating dermonecrosis, hemorrhage, vasoconstriction, edema, and erythema. However, no reaction was observed when each venom was pre-incubated (1 h, 37 degrees C) with Brazilian commercial sera prior to injection. The antivenoms also abolished the sphingomyelinase activity in vitro, suggesting the venoms of the major medically important Loxosceles spider species have generally similar toxic and enzymatic characteristics. Thus, as Brazilian commercial antivenoms are able to neutralize the dermonecrosis induced by Loxosceles venoms of diverse geographical origin, clinical studies should be undertaken on the potential for a single global Loxosceles antivenom.
Assuntos
Antivenenos/metabolismo , Reações Cruzadas/efeitos dos fármacos , Pele/patologia , Venenos de Aranha/toxicidade , Aranhas/química , Animais , Western Blotting , Brasil , Caseínas/metabolismo , Reações Cruzadas/imunologia , Edema/induzido quimicamente , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Eritema/induzido quimicamente , Fibrinogênio/metabolismo , Gelatina/metabolismo , Ácido Hialurônico/metabolismo , Necrose/induzido quimicamente , Testes de Neutralização , Coelhos , Especificidade da Espécie , Esfingomielina Fosfodiesterase/metabolismo , Venenos de Aranha/antagonistas & inibidores , Venenos de Aranha/enzimologia , Venenos de Aranha/imunologiaRESUMO
Venomous animals have toxins associated with delivery mechanisms that can introduce the toxins into another animal. Although most amphibian species produce or sequester noxious or toxic secretions in the granular glands of the skin to use as antipredator mechanisms, amphibians have been considered poisonous rather than venomous because delivery mechanisms are absent. The skin secretions of two Brazilian hylid frogs (Corythomantis greening and Aparasphenodon brunoi) are more toxic than the venoms of deadly venomous Brazilian pitvipers, genus Bothrops; C. greeningi secretion is 2-fold and A. brunoi secretion is 25-fold as lethal as Bothrops venom. Like the venoms of other animals, the skin secretions of these frogs show proteolytic and fibrinolytic activity and have hyaluronidase, which is nontoxic and nonproteolytic but promotes diffusion of toxins. These frogs have well-developed delivery mechanisms, utilizing bony spines on the skull that pierce the skin in areas with concentrations of skin glands. C. greeningi has greater development of head spines and enlarged skin glands producing a greater volume of secretion, while A. brunoi has more lethal venom. C. greeningi and A. brunoi have highly toxic skin secretions and an associated delivery mechanism; they are therefore venomous. Because even tiny amounts of these secretions introduced into a wound caused by the head spines could be dangerous, these frogs are capable of using their skin toxins as venoms against would-be predators.
Assuntos
Agressão , Venenos de Anfíbios/farmacologia , Anuros/fisiologia , Cabeça/anatomia & histologia , Animais , Anuros/anatomia & histologia , Brasil , Relação Dose-Resposta a Droga , Masculino , Camundongos , Especificidade da EspécieRESUMO
Human accidents with spiders of the genus Loxosceles are an important health problem affecting thousands of people worldwide. Patients evolve to severe local injuries and, in many cases, to systemic disturbances as acute renal failure, in which cases antivenoms are considered to be the most effective treatment. However, for antivenom production, the extraction of the venom used in the immunization process is laborious and the yield is very low. Thus, many groups have been exploring the use of recombinant Loxosceles toxins, particularly phospholipases D (PLDs), to produce the antivenom. Nonetheless, some important venom activities are not neutralized by anti-PLD antibodies. Astacin-like metalloproteases (ALMPs) are the second most expressed toxin acting on the extracellular matrix, indicating the importance of its inclusion in the antigen’s formulation to provide a better antivenom. Here we show the construction of a hybrid recombinant immunogen, called LgRec1ALP1, composed of hydrophilic regions of the PLD and the ALMP toxins from Loxosceles gaucho. Although the LgRec1ALP1 was expressed as inclusion bodies, it resulted in good yields and it was effective to produce neutralizing antibodies in mice. The antiserum neutralized fibrinogenolytic, platelet aggregation and dermonecrotic activities elicited by L. gaucho, L. laeta, and L. intermedia venoms, indicating that the hybrid recombinant antigen may be a valuable source for the production of protective antibodies against Loxosceles ssp. venoms. In addition, the hybrid recombinant toxin approach may enrich and expand the alternative antigens for antisera production for other venoms.
RESUMO
Lance-headed snakes are found in Central and South America, and they account for most snakebites in Brazil. The phylogeny of South American pitvipers has been reviewed, and the presence of natural and non-natural hybrids between different species of Bothrops snakes demonstrates that reproductive isolation of several species is still incomplete. The present study aimed to analyze the biological features, particularly the thrombin-like activity, of venoms from hybrids born in captivity, from the mating of a female Bothrops erythromelas and a male Bothrops neuwiedi, two species whose venoms are known to display ontogenetic variation. Proteolytic activity on azocoll and amidolytic activity on N-benzoyl-DL-arginine-p-nitroanilide hydrochloride (BAPNA) were lowest when hybrids were 3 months old, and increased over body growth, reaching values similar to those of the father when hybrids were 12 months old. The clotting activity on plasma diminished as hybrids grew; venoms from 3- and 6-months old hybrids showed low clotting activity on fibrinogen (i.e., thrombin-like activity), like the mother venom, and such activity was detected only when hybrids were older than 1 year of age. Altogether, these results point out that venom features in hybrid snakes are genetically controlled during the ontogenetic development. Despite the presence of the thrombin-like enzyme gene(s) in hybrid snakes, they are silenced during the first six months of life.
Assuntos
Bothrops/crescimento & desenvolvimento , Bothrops/genética , Venenos de Crotalídeos/metabolismo , Hibridização Genética , Morfogênese , Animais , Batroxobina/metabolismo , Coagulação Sanguínea/efeitos dos fármacos , Bovinos , Venenos de Crotalídeos/farmacologia , Feminino , Masculino , Proteólise , Trombina/metabolismoRESUMO
Venoms of spiders and snakes contain toxins extremely active and, thus, provide a natural source for the development of new biotechnological tools. Among the diversity of toxins present in the venom of spiders from genus Loxosceles, the phospholipases D (PLDs) show high hydrolytic activity upon lysophosphatidylcholine (LPC) and sphingomyelin (SM), generating bioactive phospholipids such as cyclic phosphatidic acid (cPA). Since this mediator has been shown to play a major role in complex signaling pathways, including inhibition of tumor cells, the PLDs may hold the key to learn how toxins could be used for therapeutic purposes. However, the strong platelet aggregation of PLDs and their lack of selectivity impose a major limitation. On the other hand, disintegrins present in the venoms of Viperidae snakes are a potent inhibitor of platelet aggregation and possess high affinity and specificity to molecules called integrins that are highly expressed in some tumor cells, such as murine melanoma B16F10. Therefore, disintegrins might be suitable molecules to carry the PLDs to the malignant cells, so both toxins may work synergistically to eliminate these cells. Thus, in this work, a recombinant PLD from Loxosceles gaucho spider was recombinantly fused to a disintegrin from Echis carinatus snake to form a hybrid toxin called Rechistatin. This recombinant toxin was successfully expressed in bacteria, showed binding activity in B16F10 murine melanoma cells and exerted a synergistic cytotoxicity effect on these cells. Therefore, the approach presented in this work may represent a new strategy to explore new potential applications for spider PLDs.
RESUMO
LiTCTP is a toxin from the Translationally Controlled Tumor Protein (TCTP) family identified in Loxosceles brown spider venoms. These proteins are known as histamine-releasing factors (HRF). TCTPs participate in allergic and anaphylactic reactions, which suggest their potential role as therapeutic targets. The histaminergic effect of TCTP is related to its pro-inflammatory functions. An initial characterization of LiTCTP in animal models showed that this toxin can increase the microvascular permeability of skin vessels and induce paw edema in a dose-dependent manner. We evaluated the role of LiTCTP in vitro and in vivo in the inflammatory and allergic aspects that undergo the biological responses observed in Loxoscelism, the clinical condition after an accident with Loxosceles spiders. Our results showed LiTCTP recombinant toxin (LiRecTCTP) as an essential synergistic factor for the dermonecrotic toxin actions (LiRecDT1, known as the main toxin in the pathophysiology of Loxoscelism), revealing its contribution to the exacerbated inflammatory response clinically observed in envenomated patients.
RESUMO
Rabbits are frequently used as models for studying coagulation and platelet disorders. However, few reports on literature have dealt with the purification and characterization of rabbit platelet proteins. Herein a protocol for the simultaneous purification of rabbit platelet factor 4 (PF4) and platelet glycoprotein IIb-IIIa (GPIIb-IIIa, integrin alpha(IIb)beta(3)) is described. Specific antibodies were raised in laying chicken, which were used for assaying PF4 by ELISA, and GPIIb-IIIa by direct immunofluorescence and flow cytometry. Furthermore, the binding of monoclonal antibodies specific for GPIIb-IIIa complex (P2), ligand-induced binding site of GPIIIa (LIBS1) and rabbit P-selectin (12A7), as well as of polyclonal IgY specific for rabbit GPIIb-IIIa, was compared in quiescent and thrombin-activated platelets. Polyclonal anti-rabbit PF4 IgY was a specific and sensitive probe that could be used for assaying PF4 in plasma samples. GPIIb-IIIa expression was increased in thrombin-activated platelets, as evaluated by flow cytometric analysis using P2 and polyclonal antibodies raised in chickens. Rabbit GPIIb-IIIa also exhibited a conformational modification that caused the appearance of ligand-induced binding sites. Increased P-selectin expression, used as a positive control, was also noticeable in thrombin-activated platelets. These data evidence that antibodies raised in laying chickens specific to rabbit PF4 and GPIIb-IIIa, as well as certain monoclonal antibodies specific for human GPIIb-IIIa, may be used for investigating rabbit platelet physiology.
Assuntos
Plaquetas/imunologia , Imunoglobulinas/química , Fator Plaquetário 4/isolamento & purificação , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/isolamento & purificação , Coelhos/imunologia , Animais , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Galinhas , Cromatografia em Agarose , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Técnica Direta de Fluorescência para Anticorpo , Cobaias , Imunoglobulinas/biossíntese , Imunoglobulinas/imunologia , Masculino , Ativação Plaquetária/imunologia , Fator Plaquetário 4/imunologia , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/imunologia , Trombina/imunologiaRESUMO
Until now, in viscero-cutaneous loxoscelism, discoloured urine has been attributed only to haemoglobinuria induced by the intravascular haemolysis caused by the venom. In this paper, 2 cases (in Brazil) of viscero-cutaneous loxoscelism with rhabdomyolysis and acute renal failure are described. Both patients presented with severe oedema, erythema and dermonecrosis at the bite site. Elevated creatine kinase levels were found in both cases (6841 and 1718 U/L) associated with severe acute renal failure (one required dialysis for 50 days). Therefore, in viscero-cutaneous loxoscelism, rhabdomyolysis secondary to intense local tissue damage can occur and should be considered as a contributing factor in acute renal failure. Creatine kinase should therefore be monitored in viscero-cutaneous loxoscelism to avoid acute renal failure and to reduce the severity of any renal damage.
Assuntos
Injúria Renal Aguda/etiologia , Rabdomiólise/etiologia , Picada de Aranha/complicações , Venenos de Aranha/intoxicação , Injúria Renal Aguda/patologia , Injúria Renal Aguda/terapia , Adolescente , Pré-Escolar , Feminino , Humanos , Masculino , Necrose , Diálise Renal , Rabdomiólise/patologia , Dermatopatias/etiologia , Picada de Aranha/patologiaRESUMO
Freshwater stingrays are very common in the Paraná, Paraguay, Araguaia, and Tocantins Rivers and tributaries in Brazil. This study presents the clinical aspects of 84 patients injured by freshwater stingrays. Intense pain was the most conspicuous symptom. Skin necrosis was observed in a high percentage of the victims, mostly fishermen and bathers. The initial therapeutic procedures, like immersion of the affected member in hot water were effective in the initial phases of the envenoming, especially in the control of the acute pain; however, they did not prevent skin necrosis. By SDS-PAGE, the freshwater stingray (Potamotrygon falkneri) venom extract presented a major band of approximately 12 kDa. Several other components distributed between 15 and 130 kDa were detected in the venom extract. Many components with molecular mass above 80 and 100 kDa have gelatinolytic and caseinolytic activities, respectively. Hyaluronidase activity was detected only in a component around 84 kDa in P. falkneri venom extract. Our results demonstrated that the presence of these enzymes could explain partially the local clinical pictures presented by patients wounded by freshwater stingray.
Assuntos
Mordeduras e Picadas/epidemiologia , Mordeduras e Picadas/terapia , Venenos de Peixe/química , Rajidae , Adulto , Animais , Mordeduras e Picadas/etiologia , Mordeduras e Picadas/patologia , Brasil/epidemiologia , Eletroforese em Gel de Poliacrilamida , Tratamento de Emergência , Feminino , Traumatismos do Pé , Água Doce , Humanos , Masculino , Necrose , Estudos ProspectivosRESUMO
Loxosceles spiders have a worldwide distribution and are considered one of the most medically important groups of spiders. Envenomation (loxoscelism) can result in dermonecrosis and, less commonly, a systemic illness that can be fatal. The mechanism of venom action is multifactorial and incompletely understood. The characteristic dermonecrotic lesion results from the direct effects of the venom on the cellular and basal membrane components, as well as the extracellular matrix. The initial interaction between the venom and tissues causes complement activation, migration of polymorphic neutrophils, liberation of proteolytic enzymes, cytokine and chemokine release, platelet aggregation, and blood flow alterations that result in edema and ischemia, with development of necrosis. There is no definitive treatment for loxoscelism. However, animal model studies suggest the potential value of specific antivenom to decrease lesion size and limit systemic illness even when such administration is delayed.
Assuntos
Picada de Aranha , Aranhas/fisiologia , Animais , Humanos , Pele/patologia , Picada de Aranha/complicações , Picada de Aranha/diagnóstico , Picada de Aranha/epidemiologia , Picada de Aranha/patologia , Picada de Aranha/fisiopatologia , Picada de Aranha/terapiaRESUMO
Human accidents caused by Loxosceles spiders may result in local dermal necrosis and, in some cases, severe systemic reactions - such as intravascular hemolysis, disseminated intravascular coagulation (DIC), renal failure and death. Since many aspects of envenomation by Loxosceles spiders remain unclear, we studied the hematological and hemostatic responses induced by the i.d. injection of 10 microg/kg Loxosceles gaucho venom in rabbits. For this purpose, total blood cell count, platelet function, coagulation tests and biochemical parameters were analysed at 3, 24, 48, 72 and 120 hours after venom administration. Thrombocytopenia and leukopenia were noted at 3 and 24 hours. Histopathological analysis of the skin lesion, performed at 24 hours after venom administration, showed a massive presence of leukocytes and platelets, hemorrhage and thrombus formation at the injection site. At 72 and 120 hours, neutrophilic leukocytosis and thrombocytosis were observed. Platelet hyperaggregation was noticeable at 48 and 72 hours. Haptoglobin and fibrinogen levels were elevated early and remained in high levels over time. Significant increases in coagulation factors V, VII, VIII, IX, X and XI were noted at 120 hours. The results showed that neither intravascular hemolysis nor DIC occurred. However, the early onset of thrombocytopenia and leukopenia are important findings that may be related to dermal necrosis formation during loxoscelism.
Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Leucopenia/induzido quimicamente , Diester Fosfórico Hidrolases/toxicidade , Coelhos/sangue , Serina Endopeptidases/toxicidade , Venenos de Aranha/toxicidade , Trombocitopenia/induzido quimicamente , Animais , Coagulação Sanguínea/fisiologia , Testes de Química Clínica , Testes Hematológicos , Injeções Intradérmicas , Leucopenia/sangue , Leucopenia/patologia , Masculino , Diester Fosfórico Hidrolases/administração & dosagem , Serina Endopeptidases/administração & dosagem , Pele/efeitos dos fármacos , Pele/patologia , Venenos de Aranha/administração & dosagem , Trombocitopenia/sangue , Trombocitopenia/patologiaRESUMO
A retrospective study analysed 359 proven or presume cases of loxoscelism seen at the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil, between 1985 and 1996. The spider was identified in 14%. The bites occurred predominantly in the urban areas (73%) between September and February. Patients > 14 years were commonest inflicted (92%) and 41% were bitten while getting dressed. Only 11% sought medical care within the first 12 hours post bite. Cutaneous loxoscelism was the commonest form presenting (96%); commonest manifestations were: pain (76%), erythema (72%), edema with enduration (66%), ecchymosis (39%). Skin necrosis occurred in 53% of patients, most frequently seen on trunk, thigh and upper arm, and when patients seek medical care more than 72 hours after bite. Local infection was detected in 12 patients (3%). Hemolysis was confirmed in 4 cases (1.1%). Generalised cutaneous rash, fever and headache were also observed in 48% of the total of patients. None of them had acute renal failure or died. Treatment usually involved antivenom administration (66%), being associated with corticosteroids (47%) or dapsone (30%). Presumptive diagnosis of loxoscelism may be established based on clinical and epidemiological findings. Further investigations are required to prove the value of antivenom and other treatment schedules.
Assuntos
Picada de Aranha/epidemiologia , Adolescente , Adulto , Antivenenos/uso terapêutico , Brasil/epidemiologia , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Picada de Aranha/tratamento farmacológicoRESUMO
Freshwater stingray accidents cause an immediate, intense, and unrelieved pain which is followed by edema, erythema and necrosis formation. Treatment for stingray envenomation is based on administration of analgesic, antipyretic and anti-inflammatory drugs. Concerning pain control, it is prescribed to immerse punctured limb on hot water to alleviate pain. There are no studies demonstrating specific targets on which stingray venom acts to promote pain. Therefore, the aim of this work was to investigate some mechanisms of Potamotrygon motoro venom (PmV) that contribute to nociception induction. Evaluating spontaneous pain behavior in mice injected i.pl. with PmV, it was seen that PmV induced both neurogenic and inflammatory pain. PmV also induced hyperalgesia in both mice and rats, evaluated through electronic von Frey and rat paw pressure test, respectively. Partial inhibition of hyperalgesia was observed in mice treated with cromolyn or promethazine, which indicated that mast cell and histamine via H1 receptor participate in the inflammatory pain. To search for some targets involved in PmVinduced hyperalgesia, the participation of TRPV1, calcium channels, neurokinins, CGRP, and norepinephrine, was evaluated in rats. It was seen that PmV-induced hyperalgesia occurs with the participation of neurokinins, mainly via NK1 receptor, CGRP, and calcium influx, through both P/Q and L-type voltage-dependent calcium channels, besides TRPV1 activation. The data presented herein indicate that PmV causes hyperalgesia in rodents which is dependent on the participation of several neuroinflammatory mediators.