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Arthropod venoms are potential sources of neuroactive substances, providing new tools for the design of drugs. The aim of this study was to evaluate the effects of Dinoponera quadriceps venom (DqV) on seizure models in mice induced by pentylenetetrazole (PTZ), pilocarpine, and strychnine. In the PTZ model, intraperitoneal treatment with DqV (0.5mg/kg) increased the time until the first seizure and the percentage of survival (155.4±27.7s/12.5%, p<0.05) compared to the control group (79.75±3.97s/0%), whereas endovenous treatment (0.1 and 0.5mg/kg) decreased the time until the first seizure (0.1mg/kg: 77.83±5.3s versus 101.0±3.3s in the control group; 0.5mg/kg: 74.43±3.9s versus 101.0±3.3s for the control group, p<0.05). We did not observe significant changes in the pilocarpine- and strychnine-induced seizure models. In assays that measured oxidative parameters in the PTZ model, intraperitoneal treatment with DqV (0.5 and 2.0mg/kg) only decreased the levels of MDA and nitrite in the cortex. However, endovenous treatment with DqV (0.1 and 0.5mg/kg) increased the levels of MDA in the cortex and hippocampus and at a dose of 0.5mg/kg in the striatum. Moreover, increased in nitrite content was observed in all three of the brain regions analyzed. Taken together, the D. quadriceps venom caused both neuroprotective and neurotoxic effects in a PTZ-induced seizure model, and this effect was dependent on the route of administration used.

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A phase I/II trial to treat massive Africanized honeybee (Apis mellifera) stings using the new apilic antivenom

Barbosa

Ferreira

Carvalho

et al. 2021

Preprint

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Safety, optimal minimum dose, and, preliminary effectiveness of a new generation Africanized honeybees (Apis mellifera) antivenom (AAV) were evaluated. A phase I/II, multicenter, non- randomized, single-arm clinical trial involving 20 participants showing multiple stings were studied. Participants have received either 2 to 10 vials of AAV based on the stings number together with a predefined adjuvant, symptomatic, and complementary treatment schedule. The primary safety endpoint was the presence of early adverse reactions within the first 24 hours after treatment. Preliminary efficacy through clinical evolution, including laboratory tests, was assessed at baseline and over the following four weeks. ELISA assays and mass spectrometry estimated the venom pharmacokinetics before, during, and after treatment. Twenty adult participants, 13 (65%) males, and 7 (35%) females, with a median age of 44 years and a mean body surface of 1.92 m2 (median = 1.93 m2) were recruited. The median number of stings was 52.5 ranging from 7 to more than 2,000. Envenoming severity was classified as 80% mild, 15% moderate, and 5% severe. According to the protocol, 16 (80%) participants received two AAV vials, 3 (15%) six vials, and one (5%) 10 vials. There was no discontinuation of the treatment due to acute adverse events and there were no late adverse reactions. Two patients showed mild adverse events with only transient itchy skin and erythroderma. All participants completed the infusion within two hours and there was no loss of follow-up after discharge. ELISA assays showed venom concentrations varying between 0.25 ng/mL and 1.479 ng/mL prior to treatment. Venom levels decreased in all cases during the hospitalization period. Surprisingly, in nine cases (45%), despite clinical recovery and without symptoms, the venom levels increased again during outpatient care 10 days after discharge. Mass spectrometry showed melittin in eight participants 30 days after the treatment. Considering the promising safety results of the investigational product for the treatment of massive Africanized honeybee attacks, added to efficacy in clinical improvement and immediate decrease in blood venom level, the AAV has shown to be safe for human use.Trial registrationUniversal Trial Number (UTN): U1111-1160-7011, Register Number: RBR-3fthf8 (http://www.ensaiosclinicos.gov.br/rg/RBR-3fthf8/).

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Cited by 5 publications

References 103 publications

Antibacterial activity of the venom of the Ponerine ant Pachycondyla striata (Formicidae: Ponerinae)

Antibacterial activity of the venom of the Ponerine ant Pachycondyla striata (Formicidae: Ponerinae)

The effects of the Brazilian antDinoponera quadriceps venom on chemically induced seizure models

A phase I/II trial to treat massive Africanized honeybee (Apis mellifera) stings using the new apilic antivenom

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