Persistent and reversible cardiac dysfunction among amateur marathon runners.

AIMS: Transient systolic and diastolic abnormalities in ventricular function have previously been documented during endurance sports. However, these described alterations may be limited by the techniques applied. We sought, using less load-dependent methods, to characterize both the extent and the chronology of the cardiac changes associated with endurance events. METHODS AND RESULTS: Transthoracic echocardiography (TTE) was performed prior to, immediately after, and approximately 1 month after completion of the 2003 Boston Marathon in 20 amateur athletes. TTE included two-dimensional, spectral and tissue Doppler (TD) and flow propagation velocity (V(p)). After completion of the marathon, global measures of left ventricular (LV) systolic function were unchanged (EF 59 +/- 6 vs. 61 +/- 4% post, P = 0.14), whereas TD-derived measures of LV systolic function [septal strain -23 +/- 5 vs. -17 +/- 4%, P = 0.007; septal strain rate (SR) -1.5 +/- 0.3 vs. -1.1+/- 0.2 s(-1), P = 0.007] and right ventricular (RV) systolic function (RV apical strain -33 +/- 4 vs. -27 +/- 5%, P = 0.001; RV apical SR -2.4 +/- 0.7 vs. -1.8 +/- 0.5, P = 0.002) were reduced. Significant changes in transmitral velocity (E/A ratio 2.0 +/- 0.5 vs.1.3 +/- 0.3, P = 0.005) and TD indices of LV and RV diastolic function (E(a) septal 9.5 +/- 1.8 vs. 8.1 +/- 1.2 cm/s post-marathon, P = 0.01) were also observed, indicating an inherent alteration in LV relaxation. Although all indices of LV and RV systolic function had returned to normal on follow-up, there were persistent diastolic abnormalities (RV E(a), 11.5 +/- 1.5 cm/s pre-marathon vs. 10.0 +/- 1.6 cm/s follow-up, P = 0.01). CONCLUSION: Marathon running leads to transient systolic and more persistent diastolic dysfunction of both the LV and the RV.     

D-dimer and inflammatory markers as predictors of functional decline in men and women with and without peripheral arterial disease

OBJECTIVES: To determine whether higher circulating levels of inflammatory and thrombotic markers are associated with greater decline in lower extremity performance. DESIGN: Prospective cohort. SETTING: Academic medical center. PARTICIPANTS: Three hundred thirty-seven men and women with lower extremity peripheral arterial disease (PAD) and 215 without PAD. MEASUREMENTS: Objective measures of leg function, including the 6-minute walk and Short Physical Performance Battery (SPPB), were obtained at baseline and annually for 3 years. D-dimer, high-sensitivity C-reactive protein, serum amyloid A, and fibrinogen levels were measured at baseline. Participants were categorized into one of three groups, ranging from low to high levels of inflammation, depending on the number of individual blood factors in the lowest and highest tertiles for each corresponding blood factor. RESULTS: Adjusting for age, sex, race, ankle brachial index, comorbidities, and other confounders, greater inflammation was associated with greater decline in the SPPB (P=.008). Results were similar when repeated in participants with and without PAD separately (P for trend=.04 for participants with PAD and .07 for participants without PAD). In fully adjusted analyses, there were no significant associations between inflammation group and decline in 6-minute walk performance. CONCLUSION: Higher baseline levels of inflammatory markers and D-dimer were associated with greater decline in the SPPB at 3-year follow-up in persons with and without PAD.     

Diabetic foot ulcer incidence in relation to plantar pressure magnitude and measurement location

AimsWe prospectively examined the relationship between site-specific peak plantar pressure (PPP) and ulcer risk. Researchers have previously reported associations between diabetic foot ulcer and elevated plantar foot pressure, but the effect of location-specific pressures has not been studied.MethodsDiabetic subjects (n = 591) were enrolled from a single VA hospital. Five measurements of in-shoe plantar pressure were collected using F-Scan. Pressures were measured at 8 areas: heel, lateral midfoot, medial midfoot, first metatarsal, second through fourth metatarsal, fifth metatarsal, hallux, and other toes. The relationship between incident plantar foot ulcer and PPP or pressure–time integral (PTI) was assessed using Cox regression.ResultsDuring follow-up (2.4 years), 47 subjects developed plantar ulcers (10 heel, 12 metatarsal, 19 hallux, 6 other). Overall mean PPP was higher for ulcer subjects (219 vs. 194 kPa), but the relationship differed by site (the metatarsals with ulcers had higher pressure, while the opposite was true for the hallux and heel). A statistical analysis was not performed on the means, but hazard ratios from a Cox survival analysis were nonsignificant for PPP across all sites and when adjusted for location. However, when the metatarsals were considered separately, higher baseline PPP was significantly associated with greater ulcer risk; at other sites, this relationship was nonsignificant. Hazard ratios for all PTI data were nonsignificant.ConclusionsLocation must be considered when assessing the relationship between PPP and plantar ulceration.     

Parallel genotyping of over 10,000 SNPs using a one-primer assay on a high-density oligonucleotide array

The analysis of single nucleotide polymorphisms (SNPs) is increasingly utilized to investigate the genetic causes of complex human diseases. Here we present a high-throughput genotyping platform that uses a one-primer assay to genotype over 10,000 SNPs per individual on a single oligonucleotide array. This approach uses restriction digestion to fractionate the genome, followed by amplification of a specific fractionated subset of the genome. The resulting reduction in genome complexity enables allele-specific hybridization to the array. The selection of SNPs was primarily determined by computer-predicted lengths of restriction fragments containing the SNPs, and was further driven by strict empirical measurements of accuracy, reproducibility, and average call rate, which we estimate to be >99.5%, >99.9%, and>95%, respectively [corrected]. With average heterozygosity of 0.38 and genome scan resolution of 0.31 cM, the SNP array is a viable alternative to panels of microsatellites (STRs). As a demonstration of the utility of the genotyping platform in whole-genome scans, we have replicated and refined a linkage region on chromosome 2p for chronic mucocutaneous candidiasis and thyroid disease, previously identified using a panel of microsatellite (STR) markers.     

The 2b protein as a minor structural component of PRRSV

Porcine reproductive and respiratory syndrome virus (PRRSV) ORF2 contains an internal ORF that codes for a small non-glycosylated protein known as 2b. Previous work had identified the presence of a 10kDa 2b protein in virus-infected cells and the induction of an anti-2b response in PRRSV-infected pigs, as well as a possible association of 2b with the virion (, Virology 287:183-191). In this study, we utilized two experimental approaches, including the use of a 2b peptide-specific monoclonal antibody, to demonstrate that the PRRSV 2b protein is an integral component of the PRRSV virion. This study suggests that 2b in PRRSV is similar to the E protein in EAV and forms a minor structural component of the virion.     

Ability of laypersons to use the cincinnati prehospital stroke scale

Objective

Early stroke recognition optimizes patients' opportunities to benefit from therapeutic options. Prehospital stroke recognition is suboptimal. If 9-1-1 dispatchers used stroke-identification tools, prehospital stroke recognition might occur more rapidly and accurately. The Cincinnati Prehospital Stroke Scale (CPSS) is a brief, effective tool used by emergency medical services and hospital personnel to identify stroke. The study's goal was to determine whether laypersons could be instructed to use the CPSS over the telephone.

Methods

Adult visitors (laypersons) to a tertiary care emergency department were enrolled. Using a mock patient, laypersons were instructed to use the CPSS via telephone by an investigator simulating a 9-1-1 dispatcher. The patient randomly portrayed clinically normal and abnormal patient types. The layperson's ability to convey CPSS instructions to the patient and relay findings to the investigator was scored.

Results

Seventy laypersons were enrolled (35 each for normal and abnormal patient types). Average age was 48 years, 63% were female, and 40% never attended college. Facial droop and speech instructions were administered with 100% accuracy. Arm drift instructions were administered with 99% accuracy. Layperson accuracies for interpreting findings were 93% for facial droop, 93% for arm drift, and 97% for speech. Overall, stroke symptoms were detected with 94% sensitivity (95% CI 87, 100) and 83% specificity (95% CI 70, 95).

Conclusion

Laypersons correctly administered and interpreted the CPSS when directed to do so over the telephone by a trained investigator. These findings suggest that the CPSS may be a useful tool in early prehospital detection of stroke by dispatchers.     

Unconventional T‐cell recognition of an arthritogenic epitope of proteoglycan aggrecan released from degrading cartilage

It has been proposed that peptide epitopes bind to MHC class II molecules to form distinct structural conformers of the same MHC II–peptide complex termed type A and type B, and that the two conformers of the same peptide–MHC II complex are recognized by distinct CD4 T cells, termed type A and type B T cells. Both types recognize short synthetic peptides but only type A recognize endosomally processed intact antigen. Type B T cells that recognize self peptides from exogenously degraded proteins have been shown to escape negative selection during thymic development and so have the potential to contribute to the pathogenesis of autoimmunity. We generated and characterized mouse CD4 T cells specific for an arthritogenic epitope of the candidate joint autoantigen proteoglycan aggrecan. Cloned T‐cell hybridomas specific for a synthetic peptide containing the aggrecan epitope showed two distinct response patterns based on whether they could recognize processed intact aggrecan. Fine mapping demonstrated that both types of T‐cell recognized the same core epitope. The results are consistent with the generation of aggrecan‐specific type A and type B T cells. Type B T cells were activated by supernatants released from degrading cartilage, indicating the presence of antigenic extracellular peptides or fragments of aggrecan. Type B T cells could play a role in the pathogenesis of proteoglycan‐induced arthritis in mice, a model for rheumatoid arthritis, by recognizing extracellular peptides or protein fragments of joint autoantigens released by inflamed cartilage.