Isolation and characterization of DM40 and DM43, two snake venom metalloproteinase inhibitors from Didelphis marsupialis serum.
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From Didelphis marsupialis serum, two antihemorrhagic proteins were isolated by DEAE-Sephacel, Phenyl-Sepharose and Superdex 200 and characterized. Their masses by mass spectrometry were 40318 AMU for DM40 and 42373 and 43010 AMU for DM43, indicating the presence of isoforms for the last. Molecular masses of 44.8 and 47.3 were obtained by SDS-PAGE, respectively for DM40 and DM43. Both inhibitors showed isoelectric points lower than 3.5 and glycosylation percentages varying from 20.5 to 29.0%, as estimated by chemical deglycosylation and amino acid analysis. N-terminal sequences of the first 17 residues of DM40 and DM43 were identical except for the exchange of R9 for P9. Both were homologous to oprin, a similar inhibitor from Didelphis virginiana serum. No evidence of complex formation between DM40 and DM43 was observed either by native PAGE or gel filtration chromatography. In addition to the antihemorrhagic activity, DM40 and DM43 inhibited the hydrolysis of casein, fibrinogen and fibronectin by Bothrops jararaca venom. DM43 also showed antilethal, antiedematogenic and antihyperalgesic activities. None of the inhibitors showed enzymatic activity on casein. Both proteins formed stable complexes with jararhagin and inhibited its hemorrhagic effect as well as the enzymatic activity of this toxin on fluorogenic substrate. (+info)
Scorpion envenomation and serotherapy in Morocco.
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A clinical and biologic study was conducted in Morocco to assess the efficiency of antivenom therapy for treating victims of scorpion stings. Epidemiologic and clinical data were collected from 275 patients envenomed by Androctonus mauretanicus mauretanicus and Buthus occitanus scorpions. Patients received antivenom or other drugs. Blood samples were collected at the time of hospital admission and 1 hr and 3 hr after treatment. Serum venom levels were quantified by using an ELISA. An association was found between clinical signs of envenoming and the level of venom in serum. Patients classified as grade II (moderate envenoming) had higher serum levels of venom level than patients classified as grade I (mild envenoming). At admission to the hospital, the mean venom concentration was not significantly different between the group not treated with antivenom, the group who received 2-5 ml of antivenom, and the group who received 10 ml of antivenom. A significant decrease in serum venom levels and an improvement in the clinical conditions were observed in patients administered 10 ml of antivenom. The lower decrease in serum venom levels in patients who received 2-5 ml of antivenom was due to lower doses of antivenom. No difference in the venom concentration was observed in patients who were not treated with antivenom. The absence of administration of antivenom increased the risk of developing clinical signs at the end of the hospitalization period. However, this risk was much higher when more than 1 hr elapsed between the time of the scorpion sting and the time of hospital admission. The results demonstrate that antivenom is effective in decreasing circulating venom and morbidity. Serotherapy is more efficient when given as soon as possible after envenomation and with adequate quantities of antivenom. (+info)
Cortical blindness: an unusual sequela of snake bite.
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Several ophthalmic effects may follow snake bite; this report describes an instance of cortical blindness that resulted from snake bite. (+info)
Antibody from mice immunized with DNA encoding the carboxyl-disintegrin and cysteine-rich domain (JD9) of the haemorrhagic metalloprotease, Jararhagin, inhibits the main lethal component of viper venom.
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Envenoming by the Brazilian pit viper, Bothrops jararaca, induces extensive local and systemic haemorrhage in humans. The severe and occasionally lethal outcome of envenoming is prevented only by administration of antivenom which is conventionally prepared by hyperimmunization of large animals with an individual venom or a range of venoms. Since snake venoms typically consist of numerous molecules, only some of which are toxic, antivenoms are antigenically crude preparations whose therapeutic value would theoretically be enhanced by restricting antibody specificity to toxic venom molecules. We report here that high-titre IgG antibody from mice immunized by the GeneGun with DNA encoding the carboxy-terminal JD9 domain of Jararhagin, a haemorrhage-inducing metalloprotease in B. jararaca venom, extensively neutralized the main lethal component of B. jararaca venom. This is to our knowledge the first study to apply DNA-based methods to preparation of antivenom; it represents a novel approach with greater immunological specificity and fewer hazards than conventional systems of antivenom production. (+info)
Occupational injuries with captive lance-headed vipers (Bothrops moojeni): experience from a snake farm in Brazil.
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We studied occupational injuries with captive lance-headed vipers (Bothrops moojeni) that occurred in a snake farm in south-eastern Brazil from February 1981 to May 1999. The risk of injury, taking into account 13 cases of snake-associated injuries (12 of them snake bites) was 2.73 per 10,000 person-days of work, and 3.51 per 100,000 venom extractions. Thirteen cases of injury occurred in seven workers, whereas 18 workers were never injured, suggesting that some individuals have a higher risk of injury than others perhaps due to lack of concentration or overconfidence. Eight episodes of occupational injuries occurring in four technicians, including a case of eye injury due to splashed venom during extraction, are reported. Assessment of whether envenoming occurred was facilitated by knowledge of the snake species and size, history of recent venom extraction and snake feeding, and examination of snake venom glands. Hypersensitivity reactions (anaphylaxis and serum sickness) to antivenom are a risk particularly to those workers who were bitten more than once and medicated previously. Antivenom therefore should not be administered to these individuals unless there is clear evidence that envenoming occurred or is likely to have occurred. Hypersensitivity to the venom is also a health concern for workers from snake farms. (+info)
Envenomation by the neotropical colubrid Boiruna maculata (Boulenger, 1896): a case report.
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This is a case report of a Boiruna maculata snake bite in a child admitted to the Hospital Municipal de Pronto Socorro de Porto Alegre, Porto Alegre, RS, Brazil. The patient was bitten on the lower left limb, and exhibited pronounced local manifestations of envenomation. She was treated with Bothrops antivenom and was discharged from the hospital five days later with marked improvement of envenomation. (+info)
Heparin-antivenom association: differential neutralization effectiveness in Bothrops atrox and Bothrops erythromelas envenoming.
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Heparin, in some regions of Brazil has been used in the treatment of bothropic accidents, but the data found in the literature are inconclusive about its effectiveness. The venoms of Bothrops atrox and of B. erythromelas were characterized according to their biological activities. The capacity of heparin in neutralizing these activities was tested with doses of 3 and 6 IU in isolated form and associated to Antibothropic Serum (ABS). It was verified that heparin, in doses of 3 and 6 IU, was not effective in neutralizing the desfibrinating and edema-forming activities of B. atrox venom and the hemorrhagic and coagulant actions of both venoms. Heparin diminished the effectiveness of the ABS in the neutralization of the hemorrhagic and edema-forming activities of the B. atrox venom. However, heparin in the 6 IU dose was capable of neutralize the edema-forming of the B. erythromelas and increase the effectiveness of the ABS. Heparin also neutralized the phospholipasic A2 activity of B. atrox (14.3%) and B. erythromelas (28.0%) venoms. For B. erythromelas venom, the associated treatment, heparin and ABS, was more effective in the neutralization of its lethal activity. (+info)
Does the aggressive use of polyvalent antivenin for rattlesnake bites result in serious acute side effects?
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OBJECTIVE: To determine the incidence and severity of acute side effects from the use of polyvalent antivenin in victims of rattlesnake bites. DESIGN: We retrospectively reviewed the records of all patients who presented with rattlesnake bites to a university teaching hospital during an 11-year period. From patient medical records, we extracted demographic data, clinical measurements, and outcomes during emergency department evaluation and subsequent hospitalization. Data regarding serum sickness were not collected. OUTCOME MEASURES: Primary outcome variables were the occurrence of immediate hypersensitivity reaction to antivenin, the type of reaction, permanent disability at hospital discharge, and mortality. RESULTS: We identified a total of 73 patients with rattlesnake bites during the study period. Bite envenomation was graded as nonenvenomated, 7 patients (10%); mild, 23 patients (32%); moderate, 32 patients (44%); and severe, 11 patients (15%). We identified 65 patients who received antivenin. Antivenin doses ranged from 1 to 30 vials per patient (mean, 12.0 +/- 6.0), for a total of 777 vials. In 43 patients (66%), 10 or more vials of antivenin were given. The mean number of vials of antivenin given to each snakebite grade were as follows: mild, 8.4 (+/-4.0); moderate, 11.8 (+/-5.7); and severe, 18.7 (+/-6.3). No deaths, amputations, or permanent disability from snakebite occurred in the patients receiving antivenin. Acute side effects of antivenin-occurring within the first 6 hours after administration-were seen in 12 patients (18%; 95% confidence interval, 10%-30%). Acute side effects consisted solely of urticaria in all but 1 patient (2%; 95% confidence interval, 0%-8%). This patient had a history of previous antivenin reaction and required a short course of intravenous epinephrine for blood pressure support. No other complications occurred. CONCLUSION: The administration of polyvalent Crotalidae antivenin is safe. Acute hypersensitivity, when it occurs, consists solely in most cases of urticaria. Serious side effects are uncommon. (+info)