Scorpions from the primeval subgenus Archaeotityus produce putative homologs of Tityus serrulatus toxins active on voltage-gated sodium channels

It has been proposed that the subgenus Archaeotityus comprises the most ancient species group within the medically important scorpion genus Tityus. cDNA encoding sodium-channel active toxins from the type species of this subgenus, Tityus clathratus (central Venezuela), have been isolated and sequenced. Two cDNAs were retrieved that encoded 61 amino acid-long putative neurotoxins named Tcl1 and Tcl2. Sequence identity was highest (87%) when both were compared with -toxin Ts1 from the Brazilian scorpion Tityus serrulatus and its homologs from T. bahiensis, T. stigmurus, and T. costatus. A Bayesian analysis indicated statistical support for the grouping of T. clathratus Tcl1 and Tcl2 with Brazilian gamma-like -toxins, reinforcing previous phylogenetic studies which suggested an evolutionary relationship between the subgenus Archaeotityus and scorpion species inhabiting southeast South America belonging to the subgenus Tityus.

HCV liver infection and liver steatosis: evidence for indirect mechanisms in genotype 3?

BACKGROUND: Hepatitis C virus (HCV) infection is associated with the appearance of liver steatosis. AIM: To search for a correlation between the number of HCV infected hepatocytes and the presence, amount and distribution of steatosis. METHODS: A total of 124 frozen liver biopsies from HCV patients (genotype 3 = 21) were studied. HCV-antigens were detected on frozen liver sections using a four steps immunoperoxidase technique. Steatosis was graded by haematoxilin-eosin counterstaining on a serial section. RESULTS: Steatosis was detected in 82 of 124 (66.1%) patients without differences between different genotypes. Uric acid, body mass index, gammaGT levels significantly correlated with steatosis in non-3 (P < 0.01, P < 0.05, P < 0.01, respectively) but not in genotype 3 patients. HCV-antigens were detected in 95 of 124 (76.6%) cases. A positive correlation between steatosis and the number of infected hepatocytes was observed only in genotype 3 patients (P = 0.06). In most cases the number of cells with steatosis greatly outnumbered that of HCV infected cells. CONCLUSION: We confirm a possible role of the virus in the genesis of steatosis in HCV genotype 3 infected patients; however, as steatosis do not appear to be directly related to the presence of HCV-antigens within single hepatocytes, an indirect, possibly cytokine mediated, mechanism might be operative.

Scorpion sting epidemiology in Montes Municipality of the State of Sucre, Venezuela: geographic distribution.

Scorpion stings were surveyed in the Montes Municipality of the State of Sucre, Venezuela, aiming to extend the information on these poisonous accidents by characterizing their geographic distribution. From 1980 to 1990, 184 cases of scorpion stings were recorded with an incidence rate of 38.6 cases per 10,000 inhabitants. The locality of San Fernando presented the highest incidence (68.3/1000) of poisonous accidents. The highest percentages of severe cases were recorded in the towns of Arenas (27%), San Lorenzo (21%), and Cocollar (19%), which are located at the foot of the Turimiquire Mountains. This region is a dispersion area of scorpions of the Tityus genus. Our results show that this region of the State of Sucre is endemic for scorpion stings which are an important public health problem.

Toxicology of a bovine paraplegic syndrome.

A clinical entity named 'bovine paraplegic syndrome' ('síndrome parapléjico de los bovinos') has spread alarmingly in the cattle-growing areas of the central and eastern plains of Venezuela. It is estimated that four million cattle are bred in the area where the disease occurs. The mortality ranges from 5 to 25% of the animals at risk, mostly pregnant or lactating cows. The principal characteristic of the bovine paraplegic syndrome is ventral or sternal decubitus, in animals that make vain efforts to stand when stimulated. The diagnosis is established when all other possible causes (e.g. paralytic rabies, botulism and blood parasites such as Anaplasma marginal, Babesia bovis, B. bigemina, and Trypanosoma vivax) have been ruled out clinically and by laboratory tests. Death always occurs, usually after a few days, and there is no known treatment. In this work, we describe results that show the presence of a toxin in the cattle suffering from, or liable to suffer from the syndrome. The toxin is produced by ruminal bacteria. In squid giant axons under voltage clamp conditions, the toxin blocks the sodium current. We detected the toxin analytically by absorbance measurements at 340 nm after reacting with picrylsulfonic acid. We obtained a good separation of the toxin with isocratic high pressure liquid chromatography, using 40% methanol in water on phenylborasil columns.