Osseointegration of titanium implants functionalised with phosphoserine-tethered poly(epsilon-lysine) dendrons: a comparative study with traditional surface treatments in sheep

The aim of this study was to analyse the osseointegrative potential of phosphoserine-tethered dendrons when applied as surface functionalisation molecules on titanium implants in a sheep model after 2 and 8 weeks of implantation. Uncoated and dendron-coated implants were implanted in six sheep. Sandblasted and etched (SE) or porous additive manufactured (AM) implants with and without additional dendron functionalisation (SE-PSD; AM-PSD) were placed in the pelvic bone. Three implants per group were examined histologically and six implants were tested biomechanically. After 2 and 8 weeks the bone-to-implant contact (BIC) total values of SE implants (43.7 ± 12.2; 53.3 ± 9.0 %) and SE-PSD (46.7 ± 4.5; 61.7 ± 4.9 %) as well as AM implants (20.49 ± 5.1; 43.9 ± 9.7 %) and AM-PSD implants (19.7 ± 3.5; 48.3 ± 15.6 %) showed no statistically significant differences. For SE-PSD and AM-PSD a separate analysis of only the cancellous BIC demonstrated a statistically significant difference after 2 and 8 weeks. Biomechanical findings proved the overall increased stability of the porous implants after 8 weeks. Overall, the great effect of implant macro design on osseointegration was further supported by additional phosphoserine-tethered dendrons for SE and AM implants.

Angiogenesis-related ultrastructural changes to capillaries in human skeletal muscle in response to endurance exercise

The ultrastructure of capillaries in skeletal muscle was morphometrically assessed in vastus lateralis muscle (VL) biopsies taken before and after exercise from 22 participants of two training studies. In study 1 (8 wk of ergometer training), light microscopy revealed capillary-fiber (C/F) ratio (+27%) and capillary density (+16%) to be higher (P ≤ 0.05) in postexercise biopsies than in preexercise biopsies from all 10 participants. In study 2 (6 mo of moderate running), C/F ratio and capillary density were increased (+23% and +20%; respectively, P ≤ 0.05) in VL biopsies from 6 angiogenesis responders (AR) after training, whereas 6 nonangiogenesis responders (NR) showed nonsignificant changes in these structural indicators (-4%/-4%, respectively). Forty capillary profiles per participant were evaluated by point and intersection counting on cross sections after transmission electron microscopy. In study 1, volume density (Vv) and mean arithmetic thickness (T) of endothelial cells (ECs; +19%/+17%, respectively) and pericytes (PCs; +20%/+21%, respectively) were higher (P ≤ 0.05), whereas Vv and T of the pericapillary basement membrane (BM) were -23%/-22% lower (P ≤ 0.05), respectively, in posttraining biopsies. In study 2, exercise-related differences between AR and NR-groups were found for Vv and T of PCs (AR, +26%/+22%, respectively, both P ≤ 0.05; NR, +1%/-3%, respectively, both P > 0.05) and BM (AR, -14%/-13%, respectively, both P ≤ 0.05; NR, -9%/-11%, respectively, P = 0.07/0.10). Vv and T of ECs were higher (AR, +16%/+18%, respectively; NR, +6%/+6%, respectively; all P ≤ 0.05) in both groups. The PC coverage was higher (+13%, P ≤ 0.05) in VL biopsies of individuals in the AR group but nonsignificantly altered (+3%, P > 0.05) in those of the NR group after training. Our study suggests that intensified PC mobilization and BM thinning are related to exercise-induced angiogenesis in human skeletal muscle, whereas training per se induces EC-thickening.

Use of a perineural coiled catheter at the sciatic nerve in dogs after tibial plateau levelling osteotomy – preliminary observations

The analgesic effects of peripheral nerve blocks can be prolonged with the placement of perineural catheters allowing repeated injections of local anaesthetics in humans. The objectives of this study were to evaluate the clinical suitability of a perineural coiled catheter (PCC) at the sciatic nerve and to evaluate pain during the early post-operative period in dogs after tibial plateau levelling osteotomy. Pre-operatively, a combined block of the sciatic and the femoral nerves was performed under sonographic guidance (ropivacaine 0.5%; 0.3 mL kg−1 per nerve). Thereafter, a PCC was placed near the sciatic nerve. Carprofen (4 mg kg−1 intravenously) was administered at the end of anaesthesia. After surgery, all dogs were randomly assigned to receive four injections of ropivacaine (group R; 0.25%, 0.3 mL kg−1) or NaCl 0.9% (group C; 0.3 mL kg−1) every 6 h through the PCC. Pain was assessed by use of a visual analogue scale (VAS) and a multi-dimensional pain score (4Avet) before surgery (T-1), for 390 min (T0, T30, T60, T120, T180, T240, T300, T360 and T390) as well as 1 day after surgery (Day 1). Methadone (0.1 mg kg−1) was administered each time the VAS was ≥40 mm or the 4Avet was ≥5. At T390 dogs received buprenorphine (0.02 mg kg−1). Data were compared using Mann–Whitney rank sum tests and repeated measures analysis of variance. Regardless of group allocation, 55% of dogs required methadone. VAS was significantly lower at T390 (P = 0.003), and at Day 1 (P = 0.002) and so was 4Avet at Day 1 (P = 0.012) in group R than in group C. Bleeding occurred in one dog at PCC placement and PCC dislodged six times of 47 PCCs placed. Minor complications occurred with PCC but allowed four repeated administrations of ropivacaine or saline over 24 h in 91.5% of the cases.

The utility of preoperative six-minute-walk distance in lung transplantation

RATIONALE The use of 6-minute-walk distance (6MWD) as an indicator of exercise capacity to predict postoperative survival in lung transplantation has not previously been well studied. OBJECTIVES To evaluate the association between 6MWD and postoperative survival following lung transplantation. METHODS Adult, first time, lung-only transplantations per the United Network for Organ Sharing database from May 2005 to December 2011 were analyzed. Kaplan-Meier methods and Cox proportional hazards modeling were used to determine the association between preoperative 6MWD and post-transplant survival after adjusting for potential confounders. A receiver operating characteristic curve was used to determine the 6MWD value that provided maximal separation in 1-year mortality. A subanalysis was performed to assess the association between 6MWD and post-transplant survival by disease category. MEASUREMENTS AND MAIN RESULTS A total of 9,526 patients were included for analysis. The median 6MWD was 787 ft (25th-75th percentiles = 450-1,082 ft). Increasing 6MWD was associated with significantly lower overall hazard of death (P < 0.001). Continuous increase in walk distance through 1,200-1,400 ft conferred an incremental survival advantage. Although 6MWD strongly correlated with survival, the impact of a single dichotomous value to predict outcomes was limited. All disease categories demonstrated significantly longer survival with increasing 6MWD (P ≤ 0.009) except pulmonary vascular disease (P = 0.74); however, the low volume in this category (n = 312; 3.3%) may limit the ability to detect an association. CONCLUSIONS 6MWD is significantly associated with post-transplant survival and is best incorporated into transplant evaluations on a continuous basis given limited ability of a single, dichotomous value to predict outcomes.

Pelvic floor muscle electromyography during different running speeds: an exploratory and reliability study.

PURPOSE Stress urinary incontinence (SUI) affects women of all ages including young athletes, especially those involved in high-impact sports. To date, hardly any studies are available testing pelvic floor muscles (PFM) during sports activities. The aim of this study was the description and reliability test of six PFM electromyography (EMG) variables during three different running speeds. The secondary objective was to evaluate whether there was a speed-dependent difference between the PFM activity variables. METHODS This trial was designed as an exploratory and reliability study including ten young healthy female subjects to characterize PFM pre-activity and reflex activity during running at 7, 9 and 11 km/h. Six variables for each running speed, averaged over ten steps per subject, were presented descriptively, tested regarding their reliability (Friedman, ICC, SEM, MD) and speed difference (Friedman). RESULTS PFM EMG variables varied between 67.6 and 106.1 %EMG, showed no systematic error and were low for SEM and MD using the single value model. Applying the average model over ten steps, ICC (3,k) were >0.75 and SEM and MD about 50 % lower than for the single value model. Activity was found to be highest in 11 km/h. CONCLUSION EMG variables showed excellent ICC and very low SEM and MD. Further studies should investigate inter-session reliability and PFM reactivity patterns of SUI patients using the average over ten steps for each variable as it showed very high ICC and very low SEM and MD. Subsequently, longer running distances and other high-impact sports disciplines could be studied.

Association between thyroid dysfunction and venous thromboembolism in the elderly: a prospective cohort study.

BACKGROUND Venous thromboembolism (VTE) and subclinical thyroid dysfunction (SCTD) are both common in elderly patients. SCTD has been related to a hypercoagulable state and increased thromboembolic risk. However, prospective data on the relationship between SCTD and VTE are lacking. OBJECTIVES To investigate the relationship between SCTD and recurrent VTE (rVTE), all-cause mortality, and thrombophilic biomarkers. PATIENTS Elderly participants with VTE. METHODS In a prospective multicenter cohort, thyroid hormones and thrombophilic biomarkers were measured 1 year after acute VTE, as both may be influenced by acute thrombosis. We defined subclinical hypothyroidism (SHypo) as elevated thyroid stimulating hormone levels (TSH=4.50-19.99 mIU/l), and subclinical hyperthyroidism (SHyper) as TSH<0.45, both with normal free thyroxine levels. Outcomes were incidence of rVTE and overall mortality during follow-up starting after the 1-year blood sampling. RESULTS Of 561 participants (58% with anticoagulation), 6% had SHypo and 5% SHyper. After 20.8 months of mean follow-up, 9% developed rVTE and 10% died. rVTE incidence rate was 7.2 (95% confidence interval:2.7-19.2) per 100 patient-years in SHypo, 0.0 (0.0-7.6) in SHyper and 5.9 (4.4-7.8) in euthyroid participants. In multivariate analyses, the sub-hazard ratio [SHR] for rVTE was 0.00 (0.00-0.58) in SHyper and 1.50 (0.52-4.34) in SHypo compared to euthyroids, without increased thrombophilic biomarkers. SHyper (HR 0.80,0.23-2.81) and SHypo (HR 0.99,0.30-3.29) were not associated with mortality. CONCLUSION In elderly patients, SHyper may be associated with lower rVTE risks. SHypo showed a non-statistically significant pattern of an association with rVTE, without increased mortality or differences in thrombophilic biomarkers. This article is protected by copyright. All rights reserved.