The urticating apparatus in the caterpillar of Lonomia obliqua (Lepidoptera: Saturniidae)

The presence of specialized cells for venom production in the Lonomia obliqua caterpillar has long been a controversial topic. In this study, we identify a cell inside the spine that specializes in the production of toxins. Our histological study showed that this glandular cell was inserted at the subapical region of the spine, in a constricted region like a ring. This cell type was not observed in all spines of the scolus. The constricted region of the spine observed by scanning electron microscopy displayed a circular groove in which the apical portion of the spine fits perfectly; however, some spines in the same scolus lacked this groove. After breaking off the spine at the most apical region, a small drop of orange or green liquid was observed to flow from its tip. These secretions were analysed by MALDI-ToF and found to possess biochemically different compositions. The green secretion demonstrated greater similarity to the haemolymph of the caterpillar than the orange secretion. Based on our findings, the spines with a groove probably contain the venom glands and produce an orange secretion. However; it is also possible that both secretions play an important role in envenoming because all spines in contact with the skin of the accidental victim should break regardless of whether they are present in a groove. (C) 2016 Elsevier Ltd. All rights reserved.

Platelet participation in the pathogenesis of dermonecrosis induced by Loxosceles gaucho venom

Loxosceles gaucho spider venom induces in vitro platelet activation and marked thrombocytopenia in rabbits. Herein, we investigated the involvement of platelets in the development of the dermonecrosis induced by L. gaucho venom, using thrombocytopenic rabbits as a model. L. gaucho venom evoked a drop in platelet and neutrophil counts 4 h after venom injection. Ecchymotic areas at the site of venom inoculation were noticed as soon as 4 h in thrombocytopenic animals but not in animals with initial normal platelet counts. After 5 days, areas of scars in thrombocytopenic animals were also larger, evidencing the marked development of lesions in the condition of thrombocytopenia. Histologically, local hemorrhage, collagen fiber disorganization, and edema were more severe in thrombocytopenic animals. Leukocyte infiltration, predominantly due to polymorphonuclears, was observed in the presence or not of thrombocytopenia. Thrombus formation was demonstrated by immunohistochemistry at the microvasculature, and it occurred even under marked thrombocytopenia. Taken together, platelets have an important role in minimizing not only the hemorrhagic phenomena but also the inflammatory and wound-healing processes, suggesting that cutaneous loxoscelism may be aggravated under thrombocytopenic conditions

Estudo do efeito do veneno da serpente Bothrops Jararaca na interação materno - fetal, em camundongos no 9º e 19º dias de prenhez

Neste estudo foi avaliado o efeito do veneno da serpente Bothrops jararaca na interação materno-fetal, em camundongos no 9º e 19º dias de prenhez. Para isso, animais no 8º dia de prenhez receberam, por via intramuscular, 4,88µg do veneno/20g de peso do corpo (grupo BjV). Como grupo controle, foram utilizados camundongos, na mesma data de prenhez, que receberam pela mesma rota, salina estéril (grupo Sal). No 9º dia de prenhez, um grupo de animais foi sacrificado para avaliação materna hemostática, hematológica e morfológica da decídua antimesometrial. Um outro grupo de animais foi a pré-termo, para avaliação externa e esquelética dos fetos, do peso médio dos fetos, e também do peso médio materno e da placenta, com o objetivo de relacioná-los ao envenenamento e, consequentemente, ao efeito sobre fetos. No 9º dia de prenhez, foi constatado um número maior de reabsorção de fetos entre os animais do grupo BjV (39%) quando comparado com o grupo Sal (15%), porém, não havia diferença estatística entre os dois grupos. O exame histológico da decídua antimesometrial dos camundongos do grupo BjV revelou a presença de células trofoblásticas gigantes e células deciduais necróticas, na interface materno-fetal. Focos hemorrágicos e células típicas inflamatórias também foram observados nessa região. O grupo BjV apresentou níveis mais baixos de fibrinogênio que o grupo controle (p<0,0001) entretanto, TP e TTPA não estavam alterados. Os leucogramas eram semelhantes, nos dois grupos estudados, não havendo diferenças entre a contagem geral e específica dos leucócitos. Nos animais que foram a pré-termo, o envenenamento não foi capaz de alterar o ganho de peso materno, ao longo da gestação, e também não alterou o peso das placentas. Entretanto, o grupo envenenado mostrou uma incidência, estatisticamente significativa (p=0,004), de animais com reabsorção total de fetos (43%) quando comparado com o grupo controle (16%) e de animais apresentando reabsorção parcial de fetos (19%), o que não foi observado entre os animais do grupo controle...(Resumo limitado a 300 caracteres).

The injury caused by the intramuscular injection of a single dose of Bothrops jararaca venom 4.88 µg /20 g body weight) to mice on day 8 of pregnancy and examined on day 9 was investigated. Macroscopic examination of envenomed mice showed a greater number of resorptions (39%) than that of saline-treated animals (15%), despite of no statistical difference. Histologically, a characteristic involution of mature decídua was noticed in saline-treated mice; however, necrotic trophoblast giant cells and decidual cells were also presente in this region of mice treated with B. jararaca venom, mainly close to the embryo. Hemorrhagic areas were also observed at maternal-fetal interface, wich contained maternal erythrocytes and polymorphonuclears. Plasma fibrinogen levels were lower in envenomed group (p<=0,0001) but prothrombin time and activated partial thromboplastin time remained unaltered. Total and differential white blood cell counts were not statistically different between groups. Thus, B. jararaca venom causes injuries not only to the fetus, but also to decidual tissue and blood coagulation of pregnant mice. It is not clear, nonetheless, whether disturbances during the development of pregnancy are due to a direct effect of venom on uterus/fetus or to homeostatic changes in dams, such as clotting disturbances, or to both of them.