Establishing relative release kinetics of faecal indicator organisms from different faecal matrices.

AIMS: A laboratory assay for comparative characterization of various faecal matrices with respect to faecal indicator organism (FIO) release using, artificial rain water. METHODS AND RESULTS: Fresh sheep and beef-cattle faeces, dairy cattle slurry and beef cattle farm yard manure (FYM) were collected from commercial units in south-west England and applied to 20 randomized 1 m(2) plots established on permanent grassland. Representative samples from each faecal matrix (n = 5) were collected on four occasions over 16 days. One gram of each sample was transferred to a sterile vial to which 9 ml of standard local rain was carefully pipetted. The vial was then rotated through 360 degrees, 20 times in 60 s to 'simulate' a standardized interaction of the faecal material with rainfall, providing an assay of comparative release potential. Appropriate decimal dilutions were prepared from the eluent. Following agitation, with a sterile spatula, the remaining faecal material and eluent in the vials were vortex mixed for 60 s before decimal dilutions were prepared from the resulting mixture, providing a quantitative assessment of the total FIO in the sample from which percentage release could be determined. Bacterial concentrations were enumerated in duplicate by membrane filtration following standard methods for FIO. Significant differences in release kinetics of Escherichia coli and enterococci from each of the faecal matrices were determined. CONCLUSIONS: Differences in release from each faecal substrate and between FIO type (E. coli and intestinal enterococci) were observed in this laboratory study. The order of release of E. coli from the faecal matrices (greatest to least, expressed as a percentage of the total present) was dairy cattle slurry > beef cattle FYM > beef-cattle faeces > sheep faeces. For intestinal enterococci the order of percentage release was dairy cattle slurry > beef-cattle faeces > beef cattle FYM > sheep faeces. SIGNIFICANCE AND IMPACT OF THE STUDY: This laboratory-based method provides the first data on the relative release kinetics of FIO from different faecal matrices in rain water. This is fundamental information needed to parameterize laboratory-based microbial models and inform approaches to field and catchment risk assessment.

Evaluation of finger ultrasound in the assessment of bone status with application of rheumatoid arthritis.

Osteoporosis associated with active rheumatoid arthritis (RA) has been demonstrated in both the axial and peripheral skeleton, especially the periarticular regions more directly affected by the disease. Quantitative ultrasound (QUS) is a recently accepted tool for the assessment of bone status, and therefore could be used to monitor bone changes in RA patients. In a cross-sectional study we measured ultrasound velocity (Ad-SOS) through the proximal phalanges in three groups of female subjects. These included: 51 patients with rheumatoid arthritis (group 1), 44 general practitioner (GP)-referred patients for osteopenia (group 2) and 52 young healthy volunteers (group 3). For groups 1 and 2 bone mineral density (BMD) of the lumbar spine and proximal femur were also measured. For the RA patients BMD of the hand, measurement of hand function (HAQ and grip strength) and disease activity (ESR and CRP) were also assessed. The precision of long-term Ad-SOS measurements on volunteers gave a root mean square coefficient of variation (CV) of 0.7% and standardized CV of 3.6%. No statistically significant effect of dominance was observed in the measured Ad-SOS between the dominant and non-dominant hand (r = 0.96, p < 0.001). Ad-SOS was found to be significantly different in the three groups (p < 0.0001). Ad-SOS was highly dependent on age (r = -0.67), with a gradual reduction (-5.2 m/s per year) after the age of 30 years for female patients in both group 1 and group 2. Ad-SOS was significantly correlated with lumbar spine, femoral neck and hand BMD, with correlation coefficients of 0.49, 0.51 and 0.72 respectively for RA patients. Finger ultrasound was moderately correlated with measures of hand function, with coefficients of 0.37 and 0.39 for HAQ and grip strength respectively. Hand BMD also correlated to the same power with these parameters. Neither finger ultrasound nor BMD was significantly correlated with ESR and CRP (measures of disease activity). We have demonstrated that bone status can be assessed quickly and cheaply using a portable QUS device. Ad-SOS relates to the measure of hand function in RA patients. Longitudinal studies are required to determine the usefulness of finger ultrasound for monitoring disease progression or the effect of treatment in RA.