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Atrial fibrillation is a common cardiac arrhythmia and can occur de novo following a surgical procedure. It is associated with increased inpatient and long-term mortality. There is limited evidence concerning new-onset atrial fibrillation following abdominal surgery. This study aimed to identify the prevalence of and risk factors for postoperative atrial fibrillation in the general surgical population. A systematic search of the Embase, MEDLINE and Cochrane (CENTRAL) databases was conducted. Studies were included in the review if they reported cases of new-onset atrial fibrillation within 30 days of the index operation. Results were evaluated qualitatively due to substantial clinical heterogeneity. Incidence rates were pooled using a weighted random-effects meta-analysis model. A total of 835 records were initially identified, from which 32 full texts were retrieved. Following review, 13 studies were included that involved 52,959 patients, of whom 10.94% (95%CI 7.22-15.33) developed atrial fibrillation. Five studies of patients undergoing oesophagectomy (n = 376/1923) had a weighted average rate of 17.66% (95%CI 12.16-21.47), compared with 7.63% (95%CI 4.39-11.98) from eight studies of non-oesophageal surgery (n = 2927/51,036). Identified risk factors included: increasing age; history of cardiac disease; postoperative complications, particularly, sepsis, pneumonia and pleural effusions. New-onset postoperative atrial fibrillation is common, and is more frequent after surgery involving the thorax. Future work should focus on stratifying risk to allow targeted prophylaxis of atrial fibrillation and other peri-operative complications. [ABSTRACT FROM AUTHOR]

The pesticide methyl parathion (MP) is widely distributed in the environment and is chemically similar to nerve agents used in chemical warfare. Detoxification of this class of compounds is a critical environmental concern. Toxicity of MP is primarily associated with the inhibition of cholinesterase activity and resulting effects on the nervous system. Methyl parathion can also induce a genotoxic effect in bacterial and mammalian cells. However, the major metabolite of MP degradation, p-nitrophenol (PNP), is generally considered less toxic. Thisstudy reports on the evaluation of the genotoxic effect of MP, PNP, and a 1:1 MP:PNP mixture, and the utility of an organophosphorus hydrolase (OPH) enzyme for degradation of MP Although MP induced a positive genotoxic response in Salmonella typhimurium TA 100 at a dose of 1,000 Mu g per plate, PNP and a l:l mixture of PNP and MP did not induce a positive response. Methyl parathion dissolved in Luria-Bertani broth containing 5% methanol was treated with genetically engineered intact Escherichia coli cells expressing OPH activity. Significant rates of MP biodegradation were observed in the liquid culture. Within 55 h, an average 95.5% of the MP was converted to PNP as measured spectrophotometrically. The genotoxic potential of extracts of OPH-treated and untreated MP-amended media was measured with S. typhimurium strain TA 100. The untreated media induced a dose-dependent genotoxic response at a dose equivalent to 54 ml of medium (MP 0.025 mg/ml) per plate, whereas the OPH-treated media failed to induce a genotoxic response. Chemical analysis indicated that about 90% of MP was removed from the media by treatment with OPH enzyme. These studies indicate that the OPH enzyme is capable of degrading MP and eliminating its genotoxic potential in liquid culture. [ABSTRACT FROM AUTHOR]

Organophosphorus hydrolase has been shown to be an effective catalyst for the continuous decontamination of a nerve agent in a continuous gas phase reactor. Very small quantities of the enzyme are sufficient to enable detoxification of low concentrations of the nerve agent for extended periods of time. In the case where the nerve agent is at high concentrations (a liquid), the enzyme has also been shown to be active in biphasic mixtures of a solvent with water. The activity and specificity of the enzyme in both environments (continuous gas phase and biphasic mixture) obey classical models of enzyme kinetics. The activity of the enzyme in such extreme environments enables optimization of systems capable of continuous gas or liquid phase biocatalytic degradation of highly toxic chemicals.

A recombinant baculovirus, Autographa californica nuclear polyhedrosis virus (AcNPV), has been utilized to express the opd (organophosphate-degrading) gene from Pseudomonas diminuta in insect tissue-culture cells (Sf9) of the fall armyworm (Spodoptera frugiperda). The broad-spectrum organophosphate hydrolase (EC 3.1.8.1) encoded by this gene is a member of a general class of enzymes [organophosphate (OP) anhydrolases] that include parathion hydrolases, di-isopropyl-fluorophosphatases (DFPases), somanases, and OP phosphotriesterases. This particular enzyme possesses the ability to hydrolyse paraoxon (P-O bond), DFP, sarin (P-F bond), VX (P-S bond) and tabun (P-CN bond), as well as a number of other extensively used organophosphorus pesticides. The enzyme produced in infected Sf9 cells is post-translationally processed and resembles the mature form of the enzyme expressed in various bacterial cells as identified by immunoprecipitation on Western blots. N-terminal sequence analysis of enzyme expressed in insect cells revealed Gly-29 as the terminal residue, whereas expression in Escherichia coli removes this residue, exposing Ser-30 at the N-terminus. Conditions for optimal expression of the enzyme in this system are described. Furthermore, hydrolytic efficiency of some OPs with purified enzyme from this system is discussed in relation to the in situ activity of Pseudomonas diminuta MG cells.