Abstract in English:A synoptic table is proposed for the families and genera of scorpions currently regarded as valid. Because there is considerable disagreement about the classification of scorpions, many changes are to be expected in the future. The classification proposed here is followed by considerations regarding the geographical distribution of each family.
Abstract in English:The mechanisms underlying the action of Indian red scorpion Buthus tamulus (BT) venom-induced augmentation of cardiopulmonary reflexes elicited by intravenous injection of 5-HT were examined in urethane anaesthetized rats. The 5-HT produced a concentration-dependent increase in time-response area of bradycardiac response, with the responses at submaximal concentrations shifted to the left after exposure to BT venom (20 µg/kg, IV). Aprotinin (6000 kallikrein inactivating unit, IV) as such had no effect on 5-HT reflex responses (bradycardia, hypotension, and apnea), but blocked the venom-induced reflex augmentation. While ondansetron (10 µg/kg, IV) completely blocked the 5-HT reflex responses, these reappeared partially after venom exposure (20 µg/kg). Exposure to bradykinin (50 µg/kg, IV) for 30 min also augmented the 5-HT-induced reflex responses similar to venom. The bradykinin-induced augmentation was also blocked by ondansetron. Results indicate that the venom-induced augmentation of cardiopulmonary reflexes is mediated through kinins sensitizing 5-HT3 receptor subtypes.
Abstract in English:It is well documented that several pharmacological substances are released within the victim's body after snakebite. These substances are also believed to be endogenously present in animals, specifically levels of myoglobin and histamine that are reported to rise after envenomation. However, there is no published data regarding the presence of these substances in venoms per se. This research reports the detection of myoglobin and histamine in snake, scorpion, honeybee, and toad venoms by immunological test. It is unlikely that the rise in levels of myoglobin and histamine is due to that added from the bite, since a single toxin devoid of such components is capable of elevating levels of these substances. Nonetheless, it is likely that the rise in levels of myoglobin and histamine after envenomation is due to the venom or toxin reacting with cells of various organs of the victim. Therefore, this phenomenon can be compared to cancer markers, which are endogeneously present in humans at low levels and elevated in cancerous states.
Abstract in English:In Brazil, more than 80% of venomous snakebites are caused by Bothrops and about 10% by Crotalus. This study evaluated 133 reported cases that occurred between 1994 and 1996 in the 52 municipalities covered by the Pouso Alegre Regional Health Center in southern Minas Gerais State. Most of the patients were male (89.5%). The most frequently attacked age bracket was that of people in their twenties, and the most frequently bitten anatomical regions were the lower limbs (77.7%), principally the feet (34.6%). Of the 124 cases stating the snake genus, 62.9% were caused by Crotalus and 37.1% by Bothrops. The conclusion of this study is that although the epidemiology of snakebites in Minas Gerais State is similar to other regions of the country, the percentage of Crotalus bites is much higher.
Abstract in English:Snakebite envenomation is a worldwide problem and in Costa Rica. The following is a retrospective review of 79 patients admitted to the Hospital Nacional de Niños (HNN) from January 1985 to September 1996. Child's age ranged from 9 months to 14 years. The M: F ratio was 1.5:1. Sixty percent of the patients lived in remote rural areas. The most common clinical signs at the time of hospitalization were pain and edema. Fifty patients (63,29%) showed moderate to severe envenomation grades. Fifty-one (64,55%) was caused by Bothrops asper. Complications during hospitalization were compartment syndrome and secondary infection. Three children died, one from disseminated intravascular coagulation, another from renal insufficiency, and the third from a perforated duodenal ulcer. Patients who underwent early fasciotomy had significantly less hospitalization and fewer infectious complications, (p < 0.001). There was no relationship between the envenomation grade and length of hospitalization (p = 0.4). The most common pathogen isolated was S. aureus. Early fasciotomy seemed to reduce the complications seen in these patients. Further studies are necessary to identify the factors that may help clinicians to decide those who should undergo fasciotomy, as well as the best moment to perform it.
Abstract in English:The effect of intramuscular (IM) injection of a sub-lethal dose of Naja haje cobra venom (0.015 mug/gm body weight) on the ultrastructure of renal cortical tissues of rabbits was studied at different time intervals after envenomation. Succinic dehydrogenase (SDH) enzyme activity was also detected in the renal cortical tubules. Three hours after venom injection, slight changes were seen in visceral cells and glomerular endothelia. The cortical tubular epithelia revealed an increase of lysosomal structures, cytoplasmic vacuolization, and nuclear irregularity. Severe ultrastructural changes were recorded 6 hours after envenomation, including hypertrophied parietal cells, blebbed visceral epithelial cells, and foot process disorganization. Dilated glomerular capillaries lined by hypertrophied endothelial cells and signs of mesangiolysis were also observed. The proximal tubular epithelia showed vesiculated endoplasmic reticulum and numerous lysosomal vacuoles, while the distal tubular epithelia were mostly necrotic. These alterations were more intense 12 hours after venom injection. Parietal and visceral cells showed similar changes to those of the six-hour group. Most of the glomerular endothelial cells lost their integrity and diffused into the capillary lumen. Mesangiolysis was also observed. The proximal tubular epithelial cells revealed severely affected cellular organelles, dilated brush borders, disruption of the basal membrane infoldings, and cellular necrosis. The distal tubular epithelia lost most of their cytoplasmic electron density and cellular organelles. Necrotic cells were also seen. Generalized mitochondrial alterations were observed in all renal cortical cell types accompanied by a marked depletion of SDH enzymatic activity in those cells. It is believed that these venom-induced non-specific lesions could be due to secondary synergistic action of more than one venom toxin, which mainly target the mitochondria in all components of renal cortical tissues. This could lead to an ischemic condition that could be responsible for the appearance of these ultrastrucural alterations.
Abstract in English:Acute myocarditis was induced in experimental dogs by subcutaneous (SC) injection of 3mg/kg of scorpion venom from Mesobuthus tamulus concanesis POCOCK (earlier called Buthus tamulus). An increase in hemoglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), packed cell volume (PCV), plasma hemoglobin (Plasma Hb) levels, and increased osmotic fragility of erythrocytes in vivo was observed after envenoming. An increase in osmotic fragility of red blood cells (RBC) was also observed when the blood in vitro was incubated with different concentrations of scorpion venom. Species- specific scorpion antivenom (SAV) was administered to different groups of animals at different time intervals following scorpion envenoming. This resulted in a decrease in Hb, MCHC, PCV, and plasma Hb levels in the envenomed animals and reversal of osmotic fragility changes of erythrocytes. It has been suggested that scorpion venom causes an autonomic storm releasing massive amounts of counter-regulatory hormones, such as catecholamines, angiotensin-II, glucagon, cortisol, and changes in insulin secretion resulting in hematological and osmotic fragility changes of erythrocytes. Administration of SAV effectively neutralized, prevented, and reversed scorpion venom toxicity and related osmotic fragility changes of erythrocytes.
Abstract in English:Recently, propolis has been attracting the attention of researchers due to various biological activities and therapeutic properties. In Brazil, propolis is produced all year long, so there may be some seasonal variations. This work was carried out in order to compare propolis collected during the four seasons by its in vitro antimicrobial activity on yeast pathogens isolated from human infections. Propolis was produced by africanized honeybees in Botucatu, São Paulo State, collected throughout a year and pooled by season. Hydroalcoholic solutions of propolis were prepared with each pool and diluted in agar, using serial concentrations of propolis from each pool. A determination of minimal inhibitory concentration (MIC) was performed. The results show that Candida tropicalis and Candida albicans were susceptible to low concentrations of propolis, the latter showing a higher susceptibility. No differences were seen in relation to seasonal effects in the minimal inhibitory concentration of propolis.