Kinetics of plasma cell‐free DNA and creatine kinase in a canine model of tissue injury

Background: Cell‐free DNA (cfDNA) comprises short, double‐stranded circulating DNA sequences released from damaged cells. In people, cfDNA concentrations correlate well with disease severity and tissue damage. No reports are available regarding cfDNA kinetics in dogs. Objectives/Hypothesis: Cell‐free DNA will have a short biological half‐life and would be able to stratify mild, moderate, and severe tissue injury. Our study aims were to determine the kinetics and biological half‐life of cfDNA and to contrast them with those of creatine kinase (CK). Animals: Three groups of 10 dogs undergoing open ovariohysterectomy, surgery for cranial cruciate ligament rupture (CCLR), or hemilaminectomy. Methods: Plasma for cfDNA and CK analysis was collected at admission, at induction of anesthesia, postsurgery (time 0) and at 6, 12, 24, 36, 48, 60, and 72 hours after surgery. Results: The biological half‐life of plasma cfDNA and CK were 5.64 hours (95% confidence interval [CI 95], 4.36–7.98 hours) and 28.7 hours (CI95, 25.3–33.3 hours), respectively. In the hemilaminectomy group, cfDNA concentrations differed significantly from admission at 6–12 hours after surgery. Creatine kinase activity differed among the surgical groups and reached a peak 6 hours after surgery. In the ovariohysterectomy and CCLR groups, plasma CK activity 72 hours after surgery did not differ from admission activity of the ovariohysterectomy group. In contrast, in the hemilaminectomy group, plasma CK activity after 72 hours did not return to the ovariohysterectomy group admission activity. Conclusions and Clinical Importance: Plasma CK activity has a longer biological half‐life than previously thought. In contrast to plasma CK activity, cfDNA has a short half‐life and could be a useful marker for peracute severe tissue injury

Invasive pneumococcal disease and the potential for prevention by vaccination in the United Kingdom

OBJECTIVES: Invasive pneumococcal disease (IPD) is associated with a high mortality despite antimicrobial therapy, but may be preventable by pneumococcal vaccination. The extent of previous exposure to pneumococcal capsular polysaccharide vaccination prior to an episode of IPD in hospitalised adults in the United Kingdom is unclear.METHODS: We conducted a retrospective cohort study in adults with IPD admitted to either of two teaching hospitals in Sheffield, United Kingdom during 1992-2000. Receipt of pneumococcal vaccination, risk factors for IPD, death and disability were determined.RESULTS: The number of cases of IPD was 552 and 187/230 patient records from one site were reviewed. According to UK pneumococcal vaccination guidelines 59% of patients should have received the vaccine and 76% of patients if updated guidelines, which include age&gt;65 years as an indication, are applied. In patients with known risk factors, excluding age, only 8% had been vaccinated. The mortality from IPD was 21% and an additional 6% suffered major complications.CONCLUSIONS: In patients hospitalised with IPD there is a high rate of pre-existing risk factors and a low rate of administration of pneumococcal vaccination. IPD incurs significant mortality, morbidity and economic cost and there is potential for reducing this by improved uptake of pneumococcal vaccination.</p

Assessing herbicide concentrations in the saturated and unsaturated zone of a Chalk Aquifer in Southern England

The behavior of the herbicides isoproturon (IPU) and chlortoluron (CTU) in ground water and shallow unsaturated zone sediments were evaluated at a site situated on the Chalk in southern England. Concentrations of IPU in ground water samples varied from <0.05 to 0.23 μg/L over a five-year period of monitoring, and were found to correlate with application of the pesticide. Concentrations of pesticides in ground water samples collected during periods of rising water table were significantly higher than pumped samples and suggest that rapidly infiltrating recharge water contains higher herbicide concentrations than the native ground water. Significant variations in herbicide concentrations were observed over a three-month period in ground water samples collected by an automated system, with concentrations of IPU ranging from 0.1 to 0.5 μg/L, and concentrations of a recent application of CTU ranging from 0.2 to 0.8 μg/L. Different extraction methods were used to assess pore water concentrations of herbicides in the unsaturated zone, and samples were analyzed by standard HPLC analysis and immunoassay (ELISA) methods. These data indicated highly variable concentrations of herbicide ranging from 4 to 200 g/ha for HPLC and 0.01 to 0.04 g/ha for ELISA, but indicate a general pattern of decreasing concentrations with depth. The results of this study indicate that transport of IPU and CTU through the unsaturated zone to shallow ground water occurs and that this transport Increases immediately following herbicide application. Measured concentrations of herbicides are generally lower than specified by the European Union Drinking Water Directive, but are observed to spike above this limit. These results imply that, while delivery of pesticides to ground water can occur as a result of normal agricultural practices, the Impact on potable supplies Is likely to be negligible due to the potential for degradation during the relatively long travel time through the unsaturated zone and high degree of dilution that occurs within the aquifer. As a result of the wide variation in concentrations detected by different techniques, it is suggested that for future site Investigations more than one sampling strategy be employed to characterize the occurrence of pesticide residues and elucidate the transport mechanisms