Critical Role of the Virus-Encoded MicroRNA-155 Ortholog in the Induction of Marek's Disease Lymphomas

Notwithstanding the well-characterised roles of a number of oncogenes in neoplastic transformation, microRNAs (miRNAs) are increasingly implicated in several human cancers. Discovery of miRNAs in several oncogenic herpesviruses such as KSHV has further highlighted the potential of virus-encoded miRNAs to contribute to their oncogenic capabilities. Nevertheless, despite the identification of several possible cancer-related genes as their targets, the direct in vivo role of virus-encoded miRNAs in neoplastic diseases such as those induced by KSHV is difficult to demonstrate in the absence of suitable models. However, excellent natural disease models of rapid-onset Marek's disease (MD) lymphomas in chickens allow examination of the oncogenic potential of virus-encoded miRNAs. Using viruses modified by reverse genetics of the infectious BAC clone of the oncogenic RB-1B strain of MDV, we show that the deletion of the six-miRNA cluster 1 from the viral genome abolished the oncogenicity of the virus. This loss of oncogenicity appeared to be primarily due to the single miRNA within the cluster, miR-M4, the ortholog of cellular miR-155, since its deletion or a 2-nucleotide mutation within its seed region was sufficient to inhibit the induction of lymphomas. The definitive role of this miR-155 ortholog in oncogenicity was further confirmed by the rescue of oncogenic phenotype by revertant viruses that expressed either the miR-M4 or the cellular homolog gga-miR-155. This is the first demonstration of the direct in vivo role of a virus-encoded miRNA in inducing tumors in a natural infection model. Furthermore, the use of viruses deleted in miRNAs as effective vaccines against virulent MDV challenge, enables the prospects of generating genetically defined attenuated vaccines

Bone Mineral Density in HIV-Negative Men Participating in a Tenofovir Pre-Exposure Prophylaxis Randomized Clinical Trial in San Francisco

Pre-exposure prophylaxis (PrEP) trials are evaluating regimens containing tenofovir-disoproxil fumarate (TDF) for HIV prevention. We determined the baseline prevalence of low bone mineral density (BMD) and the effect of TDF on BMD in men who have sex with men (MSM) in a PrEP trial in San Francisco.We evaluated 1) the prevalence of low BMD using Dual Energy X-ray Absorptiometry (DEXA) in a baseline cohort of 210 HIV-uninfected MSM who screened for a randomized clinical trial of daily TDF vs. placebo, and 2) the effects of TDF on BMD in a longitudinal cohort of 184 enrolled men. Half began study drug after a 9-month delay to evaluate changes in risk behavior associated with pill-use. At baseline, 20 participants (10%) had low BMD (Z score≤-2.0 at the L2-L4 spine, total hip, or femoral neck). Low BMD was associated with amphetamine (OR = 5.86, 95% CI 1.70-20.20) and inhalant (OR = 4.57, 95% CI 1.32-15.81) use; men taking multivitamins, calcium, or vitamin D were less likely to have low BMD at baseline (OR = 0.26, 95% CI 0.10-0.71). In the longitudinal analysis, there was a 1.1% net decrease in mean BMD in the TDF vs. the pre-treatment/placebo group at the femoral neck (95% CI 0.4-1.9%), 0.8% net decline at the total hip (95% CI 0.3-1.3%), and 0.7% at the L2-L4 spine (95% CI -0.1-1.5%). At 24 months, 13% vs. 6% of participants experienced >5% BMD loss at the femoral neck in the TDF vs. placebo groups (p = 0.13).Ten percent of HIV-negative MSM had low BMD at baseline. TDF use resulted in a small but statistically significant decline in BMD at the total hip and femoral neck. Larger studies with longer follow-up are needed to determine the trajectory of BMD changes and any association with clinical fractures.ClinicalTrials.gov: NCT00131677

Reference data for hop tests used in pediatric ACL injury rehabilitation:A cross-sectional study of healthy children

In rehabilitation, four single‐leg hop tests are frequently used for evaluation of ACL‐injured children. However, reference values on single‐leg hop performance and the corresponding limb symmetry indexes (LSIs) of healthy children younger than 15 years of age are lacking. Thus, the purpose was to describe hop performance and LSIs in healthy Danish children, and to quantify the proportion of participants passing LSI values of ≥85% as well as ≥90%. Healthy children aged 9–15 years were invited to participate in the study. Hop performance (single hop, 6‐m timed hop, triple hop, and cross‐over hop) was assessed for each leg for each hop test and expressed as absolute, normalized (to body height), and LSI values. Descriptive statistics were applied to calculate mean ±SD for all outcomes within age and gender groups. Further, the 95% reference interval was calculated for each age and gender group. A total of 531 healthy children (52% girls) were included in the study, representing seven age groups (9‐15 years). The LSI group means across all participants for the four hop tests ranged between 84 and 95%. Between 70 and 83% of the children had an LSI of ≥85%, while 50 to 65% of the children had an LSI of ≥90%. The present reference material can be used in clinical practice when evaluating hop performance in pediatric ACL patients

Progressive early passive and active exercise therapy after surgical rotator cuff repair – study protocol for a randomized controlled trial (the CUT-N-MOVE trial)

Abstract Background Rotator cuff tear is a common cause of shoulder disability and results in patients predominantly complaining of pain and loss of motion and strength. Traumatic rotator cuff tears are typically managed surgically followed by ~ 20 weeks of rehabilitation. However, the timing and intensity of the postoperative rehabilitation strategy required to reach an optimal clinical outcome is unknown. Early controlled and gradually increased tendon loading has been suggested to positively influence tendon healing and recovery. The aim of this trial is therefore to examine the effect of a progressive rehabilitation strategy on pain, physical function and quality of life compared to usual care (that limits tendon loading in the early postoperative phase) in patients who have a rotator cuff repair of a traumatic tear. Methods The current study is a randomized, controlled, outcome-assessor blinded, multicenter, superiority trial with a two-group paralleled design. A total of 100 patients with surgically repaired traumatic rotator cuff tears will be recruited from up to three orthopedic departments in Denmark, and randomized to either a progressive early passive and active movement program or a limited early passive movement program (usual care). The primary outcome measure will be the change from pre-surgery to 12 weeks post-surgery in the Western Ontario Rotator Cuff Index questionnaire. Secondary outcomes include the Disabilities Arm, Shoulder and Hand questionnaire (DASH), range of motion, strength and tendon healing characteristics from ultrasound measurements at 12 months follow up. Discussion We hypothesized that patients who receive the progressive rehabilitation strategy will benefit more with respect to pain reduction, physical function and quality of life than those who receive care as usual. If this is confirmed our study can be used clinically to enhance the recovery of patients with traumatic rotator cuff tear. Trial registration ClinicalTrials.gov, NCT02969135. Registered on 15 November 2016

The Ruptured Achilles Tendon Elongates for 6 Months After Surgical Repair Regardless of Early or Late Weightbearing in Combination With Ankle Mobilization: A Randomized Clinical Trial

Background: Treatment strategies for Achilles tendon rupture vary considerably, and clinical outcome may depend on the magnitude of tendon elongation after surgical repair. The aim of this project was to examine whether tendon elongation, mechanical properties, and functional outcomes during rehabilitation of surgically repaired acute Achilles tendon ruptures were influenced by different rehabilitation regimens during the early postsurgical period. Hypothesis: Restricted early weightbearing that permits only limited motion about the ankle in the early phase of tendon healing limits tendon elongation and improves functional outcome. Study Design:Randomized controlled trial; Level of evidence, 1. Methods: 75 consecutive patients with an acute Achilles tendon rupture were included. They underwent surgical repair, and tantalum beads were placed in the distal and proximal parts of the tendon; thereafter, the patients were randomized into 3 groups. The first group was completely restricted from weightbearing until week 7. The second group was completely restricted from weightbearing until week 7 but performed ankle joint mobilization exercises. The first and second groups were allowed full weightbearing after week 8. The third group was allowed partial weightbearing from day 1 and full weightbearing from week 5. All patients received the same instructions in home exercise guidelines starting from week 9. Results: The rehabilitation regimen in the initial 8 weeks did not significantly influence any of the measured outcomes including tendon elongation. Achilles tendon elongation and tendon compliance continued for up to 6 months after surgery, and muscle strength, muscle endurance, and patient-reported functional scores did not reach normal values at 12 months. Conclusion: Differences in rehabilitation loading pattern in the initial 8 weeks after the repair of an Achilles tendon rupture did not measurably alter the outcome. The time to recover full function after an Achilles tendon rupture is at least 12 months.Funding Agencies|Lundbeck foundation; Nordea Foundation (Center of Healthy Aging); IOC Research Center Sports Medicine Copenhagen; Danish Medical Research Council; Swedish Society for Medical Research</p