Temporal and between-site variation in helminth communities of bank voles ( Myodes glareolus) from N.E. Poland. 2. The infracommunity level.

The relative importance of temporal and spatial effects was assessed in helminth communities of bank voles (Myodes glareolus) in 3 woodland sites in N.E. Poland in the late summers of 1999 and 2002. Among common species the rank order of sites in relation to prevalence and abundance of infection was maintained between surveys. Site effects accounted for most of the deviance (in statistical models), and time was less important, so the exact location from which voles were sampled was of critical importance. The only exception was Syphacia petrusewiczi. In contrast, for derived measures such as species richness and diversity, most deviance was accounted for by host age, and the interaction between site and year was significant, implying that rank order of sites changed between years. Temporal effects on derived measures were generated primarily by a combination of relatively small changes in prevalence and abundance of the common, rather than the rare, species between the years of the study. In the medium-term, therefore, helminth communities of bank voles in N.E. Poland had a stable core, suggesting a substantial strong element of predictability.

Temporal and between-site variation in helminth communities of bank voles ( Myodes glareolus) from N.E. Poland. 1. Regional fauna and component community levels.

Helminth infections were studied in bank voles (Myodes glareolus) from 3 woodland sites in N.E. Poland in the late summers of 1999 and 2002, to assess the temporal stability of derived statistics describing the regional helminth fauna and component community structure, and spatial influence on the latter. Regional helminth fauna changed dramatically between the two years, primarily due to a fall in the abundance of Syphacia petrusewiczi but was partially compensated for by an increase in Mesocestoides lineatus and Cladotaenia globifera. It was dominated by nematodes overall, but more so in 1999 than in 2002 when larval cestodes were more frequent. Most derived parameters for component community structure varied considerably between sites and the two surveys, the hierarchical order for sites not being maintained between surveys. They were susceptible to the disproportionate influence of three relatively rare, unpredictable species with the greatest overall aggregated distribution among hosts. Jaccard's similarity index was less influenced by the rare species, showing greater stability between sites and across years. In conclusion, temporal variation confounded any site-specific characteristics of the summary measures quantified in this study and their usefulness is therefore restricted to the years in which the surveys were conducted.

Educational impact of faculty review on radiology residents' radiographic interpretations.

The objective of this study was to analyze the improvements in film reading performance made by radiology residents during their first six months of training. Five first-year residents and eight radiologic technology students each interpreted two of three matched sets of 39 films under two conditions. One set's readings were reviewed by a staff radiologist, while the other's were unreviewed. Six months later, each observer read all three sets. After the first six months of training, residents improved their reporting of findings. There was less improvement in technologists' readings. Review and instruction by staff, both in the laboratory and daily work settings, appeared to contribute to improved performance. Accuracy of residents' final diagnosis did not improve significantly. We conclude that a training system in which residents' film interpretations are reviewed by staff can lead to improved resident performance. When studied in a longitudinal fashion, these improvements are detectable within six months. This teaching system is used in many radiology departments.

Expression of amino acid transport systems in cultured human umbilical vein endothelial cells.

1. Nutrient transport in cultured human umbilical vein endothelial cells was characterized using a rapid dual-isotope dilution technique. Microcarrier beads with confluent endothelial cells were perfused in small columns, and uptake and efflux were assessed relative to D-mannitol (extracellular tracer) during a single transit through the column. 2. At tracer concentrations significant unidirectional uptakes were measured for L-leucine (53 +/- 2%), L-phenylalanine (73 +/- 2%), L-serine (40 +/- 4%), L-arginine (42 +/- 3%) and L-ornithine (26 +/- 3%). Uptake for L-proline, D-glucose, dopamine and serotonin was lower (6-10%), whereas uptake for the system A analogue 2-methylaminoisobutyric acid (2-MeAIB) was negligible. Uptakes rapidly decreased with time due to tracer efflux. 3. Endothelial cell transport of L-leucine was markedly inhibited during perfusion with 1 mM-BCH (beta-2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid, system L analogue), L-leucine, D-leucine, L-phenylalanine, L-methionine and L-DOPA. 2-MeAIB, L-cysteine, glycine, L-proline, hydroxy-L-proline, L-aspartate and beta-alanine were poor inhibitors, while L-serine and the cationic substrates L-lysine and L-arginine inhibited uptake by 10-35%. 4. When the kinetics of L-leucine transport were examined over a wide range of substrate concentrations (0.025-1 mM) transport was saturable. A single entry site analysis gave a half-maximal saturation constant Kt = 0.24 +/- 0.08 mM (mean +/- S.E.M., n = 5) and a Vmax = 27.8 +/- 4.6 nmol/min per column (approximately 3 x 10(6) cells). 5. Removal of sodium from the perfusate inhibited tracer uptake of L-leucine, L-serine and L-arginine by respectively 20 +/- 5% (n = 3), 77 +/- 5% (n = 3) and 35 +/- 4% (n = 3). 6. Our results provide the first evidence that cultured human endothelial cells of venous origin express a saturable transport system for large neutral amino acids resembling system L described in brain microvascular endothelium. Detection of Na+-dependent and Na+-independent L-arginine uptake is of interest in view of recent reports that this cationic amino acid may be the physiological precursor for nitric oxide released by endothelium.

Resident film interpretations and staff review.

In this department 22% of examinations are interpreted independently by residents outside of normal hours. Staff radiologists review these studies in a process designed to train residents and assure appropriate radiologic consultation. The resident's written reports on 2,619 examinations were analyzed before and after staff review. Each film review session lasted an average of 1.1 hr. Potential changes were discussed in 9.1% of cases and mandated in 6.3%. About two-thirds of corrections were important enough to influence patient care. Correction rates declined significantly between the first and second/third years of residency; the proportion of clinically important changes also decreased. Omissions (false-negatives) were much more common than overcalls (false-positives). Residents correctly interpreted 89% of abnormal films and 96% of normal radiographs. Staff review resulted in a net improvement in interpretation of 4% of cases initially read by first-year residents and 2% by second- and third-year. The film review process provides opportunities for close resident-staff interaction and teaching and also ensures appropriate final reports.

Radiology department management system: technologists' costs.

We developed a series of management reports to compare actual costs against expected costs for radiology departments on a more detailed level than previously available. We first developed labor standards for the most commonly employed diagnostic examinations and showed that increased patient complexity (resulting from, for example, immobility, precautions status, etc.) also increased the examination times up to 2.6-fold compared with the time required for average patients. Using labor standards and budgeted and actual volumes of average and complex patients, we calculated four types of variances: volume variance, examination mix variance, patient complexity variance, and technologist efficiency variance. Monitoring the technologist efficiency variance over time could be one key piece of information for improving departmental productivity.