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Abstract: Bioscavengers are considered as promising antidotes against organophosphate poisoning. We focused on a bacterial phosphotriesterase (PTE) expressed in Escherichia coli. The main disadvantage of this non-human catalytic bioscavenger is its relatively short half-life in the organism and strong immunogenicity after repeated administration. Therefore, we prepared different methoxy polyethylene glycol (MPEG)-conjugated recombinant PTE as a potential catalytic bioscavenger with the aim to improve its biological properties. Enzyme was modified with two linear monofunctional MPEG derivatives with reactive aldehyde group of molecular weight 2kDa and 5kDa. We optimized reaction conditions (reagent ratios, temperature and duration of modification reaction) and we prepared homogeneous population of fully modified recombinant PTE with molecular weight around 52kDa and 76kDa, respectively. Modified PTE was characterized using SDS-PAGE and MALDI-TOF and by determining K m and V max. We also investigated thermal stability of modified enzyme at 37°C. Based on our results, for future in vivo evaluation of pharmacokinetics and pharmacodynamics properties, we selected recombinant PTE modified with 5kDa MPEG aldehyde for its superior thermal stability. [ABSTRACT FROM AUTHOR]

The broad-spectrum reactivator is a valuable oxime able to reactivate acetylcholinesterase (AChE) inhibited by nerve agents and pesticides. At present there are many AChE reactivators (oximes) which are suitable candidates as broad-spectrum reactivators and among them is the oxime HI-6, highly enough thought of to have been recommended by many armies for use as a universal antidote. In this study, we wanted to establish whether the designation "broad-spectrum" is a an accurate description or if there are some lacks in reactivation of nerve agents or pesticides. For this purpose, the general in vitro test for the evaluation ofAChE reactivators was used. Tabun, sarin, cyclosarin, soman, VX agent, Russian VX were used as nerve agents for testing, and chiorpyrifos, paraoxon, methyl-chiorpyrifos and dichlorvos (DDVP) were used as typical examples of organophoshorus pesticides. The results obtained showed that oxime HI-6 did .not reactivate tabun- and DDVP-inhibited AChE, and, in the case of the other pesticides, only a high dose of oxime HI-6 was able to reactivate pesticide-inhibited AChE. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the health status and the most common health problems occurring in beef cattle in the Czech Republic. Thirty five beef herds of different breeds were monitored from 1 January to 31 December 2006. The health status of 4872 animals (2601 cows and 2271 of their calves) was analyzed. Herds of up to 50 cows and those over 50 cows were evaluated both separately and together. Farm management data were collected by means of a questionnaire completed by the farmers. Both geographic and herd characteristics were evaluated, as well as the course of calving, mortality and morbidity in calves, and disease occurrence in cows. Calving was unassisted in about 80% of the cows, and the conception rate was approximately 90%. More difficult courses of calving were reported from the small herds than from the large ones (p < 0.001). Total calf losses were 10% on the average. Most calf deaths occurred during the first week of life (p < 0.01), the most common cause of death being diarrhoea (p < 0.001). The situation was similar in large and small herds. Diarrhoea was also most often diagnosed in those calves that survived the early life stage. At the age of 120 days, the calves that had suffered from diarrhoea showed a lower body weight by 12.6 kg than the calves of the same age from the same herd that did not have diarrhoea. The occurrence of diarrhoea in small and large herds was 12.1% and 6.7% per herd, respectively (p < 0.05). Also, other health disorders were more often reported from small herds, in calves as well as in adult cows (p < 0.001). [ABSTRACT FROM AUTHOR]