In vivo monitoring of implant osseointegration in a rabbit model using acoustic sound analysis

Implant osseointegration can currently only be assessed reliably post mortem. A novel method that relies on the principle of acoustic sound analysis was developed to enable examination of the longitudinal progress of osseointegration. The method is based on a magnetic sphere inside a hollow cylinder of the implant. By excitation using an external magnetic field, collision of the sphere inside the implant produces a sound signal. Custom‐made titanium implants equipped thusly were inserted in each lateral femoral epicondyle of 20 New Zealand White Rabbits. Two groups were investigated: Uncoated, machined surface versus antiadhesive surface; and calcium phosphate‐coated surface versus antiadhesive surface. The sound analysis was performed postoperatively and weekly. After 4 weeks, the animals were euthanized, and the axial pull‐out strengths of the implants were determined. A significant increase in the central frequency was observed for the loose implants (mean pull‐out strength 21.1 ± 16.9 N), up to 6.4 kHz over 4 weeks. In comparison, the central frequency of the osseointegrated implants (105.2 ± 25.3 N) dropped to its initial value. The presented method shows potential for monitoring the osseointegration of different implant surfaces and could considerably reduce the number of animals needed for experiments. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:606–612, 2014.     

Morbidity and Mortality in the Thirty-Day Period Following Total Hip Arthroplasty: Risk Factors and Incidence

The study sought to ascertain the incidence rates and risk factors for 30-day post-operative complications after primary total hip arthroplasty (THA). Complications were categorized as systemic or local and subcategorized as major or minor. There were 17,640 individuals who received primary THA identified from the 2006-2011 ACS NSQIP. The mortality rate was 0.35% and complications occurred in 4.9%. Age groups ≥ 80 years (P <0.001) and 70-79 years old (P = 0.003), and renal insufficiency (P = 0.02) best predicted mortality. Age ≥80 years (P <0.001) and cardiac disease (P = 0.01) were the strongest predictors of developing any postoperative complication. Morbid obesity (P <0.001) and operative time > 141 minutes (P <0.001) were strongly associated with the development of major local complications.     

Transgenic angiotensin-converting enzyme 2 overexpression in vessels of SHRSP rats reduces blood pressure and improves endothelial function

Rat models of hypertension, eg, spontaneously hypertensive stroke-prone rats (SHRSP), display reduced angiotensin-converting enzyme 2 (ACE2) mRNA and protein expression compared with control animals. The aim of this study was to investigate the role of ACE2 in the pathogenesis of hypertension in these models. Therefore, we generated transgenic rats on a SHRSP genetic background expressing the human ACE2 in vascular smooth muscle cells by the use of the SM22 promoter, called SHRSP-ACE2. In these transgenic rats vascular smooth muscle expression of human ACE2 was confirmed by RNase protection, real-time RT-PCR, and ACE2 activity assays. Transgene expression leads to significantly increased circulating levels of angiotensin-(1-7), a prominent product of ACE2. Mean arterial blood pressure was reduced in SHRSP-ACE2 compared to SHRSP rats, and the vasoconstrictive response to intraarterial administration of angiotensin II was attenuated. The latter effect was abolished by previous administration of an ACE2 inhibitor. To evaluate the endothelial function in vivo, endothelium-dependent and endothelium-independent agents such as acetylcholine and sodium nitroprusside, respectively, were applied to the descending thoracic aorta and blood pressure was monitored. Endothelial function turned out to be significantly improved in SHRSP-ACE2 rats compared to SHRSP. These data demonstrate that vascular ACE2 overexpression in SHRSP reduces hypertension probably by locally degrading angiotensin II and improving endothelial function. Thus, activation of the ACE2/angiotensin-(1-7) axis may be a novel therapeutic strategy in hypertension.     

Effect of SAMe-TT2R2 score and genetic polymorphism on the quality of anticoagulation control in Qatari patients treated with warfarin

Journal of Thrombosis and Thrombolysis - There is no strong evidence on pharmacogenetics role on the quality of INR control after the initiation phase and on the maintenance of stable INR on the...     

Iatrogenic Right Atrial Thrombus Complicated by Pulmonary Embolism: Management and Outcomes

Right atrial thrombus can originate from distal venous sources or can be iatrogenic, secondary to the placement of central venous catheters, atrial devices, or surgeries. One of the most common complications of Central Venous Catheters (CVCs) is thromboembolism, which can be either fixed to the right atrium or can be free-floating. Device-related Right Atrial Thrombosis (RAT) can result in catheter occlusion, vascular occlusion, infection, and pulmonary embolism. The true incidence of these complications is unknown because the diagnosis may not be considered in asymptomatic patients, and it might be missed by Transthoracic Echocardiography (TTE). In this literature review, we discuss iatrogenic etiologies of RAT that is complicated by pulmonary embolism. We highlight the importance of maintaining a high index of suspicion of iatrogenic RAT, possible complications, and its management.     

Pediatric apheresis with a novel apheresis device with electronic interface control

BACKGROUND: Cancer in children, and specifically cancer requiring autologous stem cell transplantation, is rare. As a consequence, though, experience with pediatric stem cell apheresis collections is limited. Challenges of apheresis in small children (<20 kg) include small total blood volume, issues with venous access, concerns about tolerable anticoagulant doses, and limitations in product volumes that can safely be collected. STUDY DESIGN AND METHODS: This article presents a small series of autologous “stem cell” apheresis procedures in infants and toddlers weighing between 5.5 and 20 kg, the first ones performed with a novel leukapheresis device (Spectra Optia MNC v.3.0, Terumo BCT) to be reported. Some features of the system are described that can be used to achieve favorable apheresis outcomes in small children. RESULTS: Apheresis procedures were uneventful and successful with similar extraction efficiencies (median preapheresis collection efficiency [CE2], 36%) as in adult patients. At 58%, platelet attrition was considerable. CONCLUSION: Our data indicate that stem cell apheresis with the Spectra Optia MNC v.3.0 in very small donors is feasible, safe, and associated with very small product volumes.     

IL-4 influences the differentiation and the susceptibility to activation-induced cell death of human naive CD8+ T cells

It is now well established that the cytokine environment influences the activation, differentiation, proliferation and death of T lymphocytes during the primary response to antigen. Using an in vitro model, we investigated the influence of IL-4, added at the onset of TCR stimulation, on phenotypic and functional markers of naive CD8+ T cell activation including the up-regulation of activation markers, proliferation as well as the susceptibility to activation-induced cell death (AICD). We report that IL-4, unlike IL-2 added at the onset of repeated TCR stimulation of naive CD8+ T cells prevents AICD, in part due to its ability to maintain the level of the survival-related protein Bcl-2. Moreover, TCR-triggered activation of naive CD8+ T cells in the presence of IL-4 leads to the development of a CD8+ T cell subset that proliferates normally, but which fails to exhibit characteristic activation parameters such as the up-regulation of CD25 and Granzyme B. Taken together, these results demonstrate that exposure to IL-4 during primary activation influences CD8+ T cell differentiation by inducing the development of a sub-population of AICD-resistant, proliferation-competent cells that do not show some of the typical features of CD8+ T cell activation.