Social Networking Technology, Social Network Composition, and Reductions in Substance Use Among Homeless Adolescents

Peer-based prevention programs for homeless youth are complicated by the potential for reinforcing high-risk behaviors among participants. The goal of this study is to understand how homeless youth could be linked to positive peers in prevention programming by understanding where in social and physical space positive peers for homeless youth are located, how these ties are associated with substance use, and the role of social networking technologies (e.g., internet and cell phones) in this process. Personal social network data were collected from 136 homeless adolescents in Los Angeles, CA. Respondents reported on composition of their social networks with respect to: home-based peers and parents (accessed via social networking technology; e.g., the internet, cell phone, texting), homeless peers and agency staff (accessed face-to-face) and whether or not network members were substance-using or non-substance-using. Associations between respondent’s lifetime cocaine, heroin, and methamphetamine use and recent (previous 30 days) alcohol and marijuana use were assessed by the number of non-substance-using versus substance-using ties in multivariate linear regression models. 43% of adolescents reported a non-substance-using home-based tie. More of these ties were associated with less recent alcohol use. 62% of adolescents reported a substance-using homeless tie. More of these ties were associated with more recent marijuana use as well as more lifetime heroin and methamphetamine use. For homeless youth, who are physically disconnected from positive peers, social networking technologies can be used to facilitate the sorts of positive social ties that effective peer-based prevention programs require

Exchange of functional domains between a bacterial conjugative relaxase and the integrase of the human adeno-associated virus

Endonucleases of the HUH family are specialized in processing single-stranded DNA in a variety of evolutionarily highly conserved biological processes related to mobile genetic elements. They share a structurally defined catalytic domain for site-specific nicking and strand-transfer reactions, which is often linked to the activities of additional functional domains, contributing to their overall versatility. To assess if these HUH domains could be interchanged, we created a chimeric protein from two distantly related HUH endonucleases, containing the N-terminal HUH domain of the bacterial conjugative relaxase TrwC and the C-terminal DNA helicase domain of the human adeno-associated virus (AAV) replicase and site-specific integrase. The purified chimeric protein retained oligomerization properties and DNA helicase activities similar to Rep68, while its DNA binding specificity and cleaving-joining activity at oriT was similar to TrwC. Interestingly, the chimeric protein could catalyse site-specific integration in bacteria with an efficiency comparable to that of TrwC, while the HUH domain of TrwC alone was unable to catalyze this reaction, implying that the Rep68 C-terminal helicase domain is complementing the TrwC HUH domain to achieve site-specific integration into TrwC targets in bacteria. Our results illustrate how HUH domains could have acquired through evolution other domains in order to attain new roles, contributing to the functional flexibility observed in this protein superfamily.This work was supported by the Medical Research Council (MRC) grant MR/N022890/1 to EH and grant 1001764 to RML; National Institutes of Health (NIH) grant RO1-GM09285 to CRE; Spanish Ministry of Economy and competitiveness (MINECO) grant BIO2013-46414-P to ML and AFM is supported by a Doc.Mobility fellowship from the Swiss National Science Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Latissimus Dorsi Tendon Repair

Background: Latissimus dorsi tendon ruptures are rare injuries that can occur in overhead or throwing motions and are almost always sports related. Indications: Latissimus dorsi tendon ruptures are largely treated nonoperatively, although surgical repair is indicated for the young active patient looking to return to a high level of sport and for those with complete avulsion injuries or mid-substance tendon tears. Technique Description: Depending on the degree of tendon retraction, anteroinferior or posteroinferior axillary incision is made. After the tendon is mobilized, sutures are placed in a Krackow fashion through the bulk of the tendon, and the tendon footprint is prepared by gently decorticating the surface of the humerus, just anterior and inferior to the teres major insertion point. Two Arthrex Pec Buttons are then loaded into the superior and inferior limbs of the suture tape and 2 unicortical holes are drilled into the footprint of the insertion site. The superior button is placed first and then tensioned to allow the latissimus dorsi to be pulled to the bone. Next, the second button is placed, though this is not tensioned until later at the time of the biceps tenodesis. Finally, the procedure is visualized and well inspected to ensure appropriate location of the tendon and securing hardware. Results: After an appropriate rehabilitation protocol is followed for up to 6 months postoperatively, acute repair of a ruptured latissimus dorsi tendon allows for near to complete restoration of patient functionality and strength, with return to full activity possible within 6 to 8 months. Conclusion: Surgical repair of a ruptured latissimus dorsi tendon is effective in restoring upper extremity strength and functionality and is associated with high patient satisfaction. The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication

Osteochondral Allograft Transplantation

Background: Articular cartilage lesions are a significant cause of morbidity and impaired knee function, and attempts to surgically repair damaged cartilage have failed to reliably reproduce native cartilage. Thus, osteochondral allograft transplantation is an effective one-step procedure to repair large cartilage defects. Indications: Osteochondral allograft transplantation is indicated for young active patients with large focal defects, those with a history of previous cartilage repair, and those with cartilage-related degenerative disorders such as osteonecrosis, osteochondritis dissecans, and/or post-traumatic osteochondral defects. Technique Description: In short, after the focal chondral defect is identified, a socket is created with specific dimensions in depth and diameter. The donor cartilage is then secured in a graft station, and a sizing guide is placed through a bushing to confirm the allograft harvest location. Using stabilization from the graft station arm, a coring reamer is then advanced through the donor cartilage, and a saw is used to allow for easy removal of the graft from the donor condyle. The plug is then fashioned to fit the exact dimensions of the socket created earlier in the procedure. A cut on the donor plug is made to fashion the plug to the appropriate depth. A rongeur is used to make the plug more bullet shaped at the end to allow the plug to enter the socket more easily. Small holes are then drilled into the base of the socket to help promote incorporation of the plug into the socket during the healing process. After the socket is irrigated, the plug is then placed into the socket, and a tamp is used to gently tap the cartilage until it is flush with the surrounding surface. Results: After an appropriate rehabilitation protocol is followed for up to 10 months postoperatively, osteochondral allograft transplantation allows for near-to-complete restoration of patient functionality and strength, with return to full activity possible within 1 year. Conclusion: Acute repair of large focal chondral defects is effective in restoring knee strength and functionality and is associated with high patient satisfaction. The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication

Hemorrhage control training promotes resilience-associated traits in medical students

Objective: Given rising rates of physician burnout, the potential for clinical skills training programs to develop and reinforce resilience-associated traits in medical students warrants investigation. The primary objective of this study was to examine the impact of a hemorrhage control training program on resilience-associated traits (role-clarity, self-efficacy, and empowerment) in medical students. A secondary objective was to examine the differential impact of additional hands-on skills training.Design: This was a prospective study of medical students participating in an established hemorrhage control training program, utilizing pre-, mid-, and post-training questionnaires. The program included both an in-person lecture and hands-on skills training. Primary endpoints were self-reported increases in role clarity (when the hemorrhage control skills would and would not be applicable), self-efficacy (confidence in ability to use the skill), and empowerment (to act in a situation where the skill was needed).Setting: Harvard Medical School, Boston, Massachusetts.Participants: One hundred and twenty-six Harvard Medical School students participated.Results: There was a significant increase at each stage of training in self-reported role clarity about when to apply hemorrhage control skills (p \u3c 0.01) and when not to apply them (p \u3c 0.01); confidence in application of the skill (p \u3c 0.01); as well as empowerment to apply the skill when appropriate (p \u3c 0.01).Conclusions: Hemorrhage control training, a first response-related clinical skills program, is a promising domain for development and reinforcement of resilience-associated traits in medical students, particularly when the program includes hands-on skills training. Providing experiential learning opportunities that are designed not only for skills-specific outcomes, but also to reinforce such resilience-associated traits as role-clarity, self-efficacy, and empowerment provides an essential integrated perspective

Osteoarthritis Classification Scales: Interobserver Reliability and Arthroscopic Correlation

The MARS Group* Background: Osteoarthritis of the knee is commonly diagnosed and monitored with radiography. However, the reliability of radiographic classification systems for osteoarthritis and the correlation of these classifications with the actual degree of confirmed degeneration of the articular cartilage of the tibiofemoral joint have not been adequately studied. Methods: As the Multicenter ACL (anterior cruciate ligament) Revision Study (MARS) Group, we conducted a multicenter, prospective longitudinal cohort study of patients undergoing revision surgery after anterior cruciate ligament reconstruction. We followed 632 patients who underwent radiographic evaluation of the knee (an anteroposterior weight-bearing radiograph, a posteroanterior weight-bearing radiograph made with the knee in 45°of flexion [Rosenberg radiograph], or both) and arthroscopic evaluation of the articular surfaces. Three blinded examiners independently graded radiographic findings according to six commonly used systems-the Kellgren-Lawrence, International Knee Documentation Committee, Fairbank, Brandt et al., Ahlbäck, and Jäger-Wirth classifications. Interobserver reliability was assessed with use of the intraclass correlation coefficient. The association between radiographic classification and arthroscopic findings of tibiofemoral chondral disease was assessed with use of the Spearman correlation coefficient. Results: Overall, 45°posteroanterior flexion weight-bearing radiographs had higher interobserver reliability (intraclass correlation coefficient = 0.63; 95% confidence interval, 0.61 to 0.65) compared with anteroposterior radiographs (intraclass continue