A biodistribution study of Hemiscorpius lepturus scorpion venom and available polyclonal antivenom in rats

The purpose of the present study was to investigate the biodistribution profile of the venom of Hemiscorpius lepturus, the most dangerous scorpion in Iran. Blood and tissue samples were taken at various predetermined intervals during a 400-minute period for the venom and a 360-minute period for the antivenom in rats. The radio-iodination was carried out using the chloramine-T method. The results showed that the descending order of venom uptake was skin, kidneys and intestine, respectively. The descending order of polyclonal antivenom uptake was kidneys, intestine, heart and lungs. The calculated pharmacokinetic parameters of the venom were Telimination half-life = 521.5 ± 12.6 minutes; Vd/F (apparent volume of distribution) = 14.9 ± 3.3 mL; clearance (CL/F, apparent total clearance of the drug from plasma) 0.02 ± 0.005 mL/minute and for the antivenom Telimination half-life = 113.7 ± 7.4 minutes; Vd/F = 13 ± 1.2 mL and CL/F 0.08 ± 0.01 mL/minute. The pharmacokinetics profile comparison of the venom with that of the antivenom shows that serotherapy may be more effective if administered within 2-4 hours following envenomation by H. lepturus.(AU)

Symptom patterns in adult patients stung by scorpions with emphasis on coagulopathy and hemoglubinuria

The aim of this retrospective descriptive study was to highlight clinical manifestations 24-48 hours following referral of adult patients stung by scorpions. This study contains clinical records of 290 patients admitted to Razi Hospital due to scorpion stings in Ahvaz, Khuzestan province from 2004 to 2005. The most prevalent patient age range was 15-20 years (30.3%). The most common sting location (41.3%) was the upper extremity; nearly half (49.6%) had been admitted within 6-24 hours following sting, while a large majority (85.5%) were hospitalized for 24-48 hours. A total of 116 (40%) patients presented hemoglobinuria. Contrary to available prior reports, the symptoms in none of the patients were accompanied by neurological manifestations. Kidney manifestations (BUN, creatinine), coagulopathy and transfusion were observed in patients with blood cell lysis and hemoglobinuria. The kidney problems were seen more in patients who had been admitted more than 24 hours after the accident. Overall, the findings demonstrate that coagulation and hemoglobinuria signs produced by scorpion sting in Ahvaz differ significantly from those reported elsewhere.

In vivo pharmacological study on the effectiveness of available polyclonal antivenom against Hemiscorpius lepturus venom

The available Razi Institute antivenom is still, empirically, used by intramuscular (IM) administration for the treatment of scorpion stings in humans by six medically dangerous species including Hemiscorpius lepturus (H. lepturus). The aim of this study was to assess the neutralizing ability and effectiveness of the antivenom in inhibiting hemoglobinuria, biochemical changes, increased microalbuminuria and urinary lactate dehydrogenase (LDH) following H. lepturus sting. Simultaneous intramuscular administration of 10 μL and 100 μL of antivenom, after 24 hours, had no significant preventive effect on the extent and degree of hemoglobinuria or proteinuria produced in venom-treated rats. After IM administration of antivenom, no significant changes in decreased red blood cell (RBC) count and hemoglobin were observed. Immediate intramuscular administration of 10 μL of antivenom had no significant effects on both LDH and microalbuminuria. The present findings did not present correlation with clinical signs. Therefore, to fully assess the efficacy of the available antivenom and make appropriate recommendations, more in vivo or in vitro investigations including antigen-antibody interaction, enzymatic analysis and route-dependent administration are required.(AU)

Clinical and biochemical manifestation produced by scorpion (Hemiscorpius lepturus) venom in experimental animals

Several studies have been published about the clinical and biochemical manifestations produced by the venom of scorpions of the Buthidae family, but very few reports have indicated the manifestations induced by the venom of the Scorpionidae family. Hemiscorpius lepturus is an important scorpion species present in the south and southwestern part of Iran, causing morbidity and mortality in children and adults. For the present study, H. lepturus venom was extracted by electric shock and subcutaneously injected (6.3mg/kg) into a group of six rabbits. Blood collection was carried out before and three hours after venom injection for determination of osmotic fragility and levels of blood sugar, alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine phosphokinase (CPK) and alkaline phosphatase (ALP). In vitro studies were also carried out to verify the osmotic fragility of red blood cells (RBCs) exposed to venom concentrations ranging from 0-90µg/2ml blood. Results showed the extreme effect of this venom on the lysis of RBCs both in vitro and in vivo. Venom injection caused significant (p>0.001) increase in ALT, AST, LDH and blood sugar levels. There was also an increase in CPK, and ALP levels after venom injection; however, it was not statistically significant. All animals died four hours after having received the venom. The current study revealed that the neurological effect of H. lepturus venom is similar to that of scorpions of the Buthidae family. However, they differ in RBCs lysis, which was highly significant when induced by H. lepturus venom, probably due to the presence of a type of phospholipase in this venom. Further studies are needed to provide a clearer view of the mechanism of action of H. lepturus venom.(AU)

Biochemical changes and manifestations of envenomation produced by Odonthobuthus doriae venom in rabbits

Many toxins from scorpion venoms cause neurotransmitters release by activating the autonomic system. The aim of the present work was to determine osmotic fragility of red blood cells (RBCs) and serum biochemical changes produced by the venom of Odonthobuthus doriae (O. doriae), a dangerous species of scorpion in Iran. For this study we selected 2 groups, each one containing 10 New Zealand white rabbits weighing 2 ± 0.2 kg. In vivo and in vitro osmotic fragilities as well as packed cell volume (PCV) were determined. Serum was separated and used for determination of glucose, blood urea nitrogen (BUN), creatinine, uric acid (UA), triglycerides, cholesterol, aspartate aminotransferase (AST, EC 2.6.1.1), and alanine aminotransferase (ALT, EC 2.6.1.2). Results indicate that Odonthobuthus doriae venom (0.5 mg/kg, IV) causes a significant increase (p<0.05) of serum glucose, UA, PCV, ALT, and AST. Increase was also observed in BUN, but it was not statistically significant. On the other hand a significant decrease (p<0.05) was observed in triglycerides and cholesterol levels. Increased in vivo osmotic fragility of RBCs was significant too, but in vitro osmotic fragility did not show a significant change. These results support the hypothesis that the biochemical variation caused by scorpion venom can be due to an autonomic storm and release of catecholamines.(AU)