Chorioallantoic membrane angiogenesis model for tissue engineering: a new twist on a classic model

Tissue-engineering (TE) applications include the isolation, culture, and seeding of cells into a suitable matrix or scaffold before in vivo transplantation. After transplantation, vascularization of the scaffold is a principal limiting factor for cell viability for the first 6-8 days posttransplantation. A model for systematic analysis of this process has been developed. Fertilized White Leghorn eggs were incubated (at 37.8 degrees C in 60% relative humidity) and opened on day 3 of incubation. Preadipocyte-seeded fibrin constructs were implanted in a specially designed plastic cylinder and placed through the opening on the surface of the chorioallantoic membrane (CAM) on day 8 of incubation. Vascularization of the constructs by chorioallantoic blood vessels was assessed for up to 8 days posttransplantation. The survival rate for embryos receiving transplanted constructs was about 90%. Histology confirmed transplant cell viability at day 4 posttransplantation and vascularization of the constructs by avian endothelial cells began at this time. A new in vivo model to study the effect of angiogenesis in TE constructs, including assessments of viability, proliferation, and differentiation of transplanted cells and biomaterial properties, is presented. Advantages include easy access to the vascular network of the CAM, lack of immunocompetence, low costs, and avoidance of animal experiments.     

The Use of Behavior Change Theory in Internet-Based Asthma Self-Management Interventions: A Systematic Review

Background

The high prevalence rate of asthma represents a major societal burden. Advancements in information technology continue to affect the delivery of patient care in all areas of medicine. Internet-based solutions, social media, and mobile technology could address some of the problems associated with increasing asthma prevalence.

Objective

This review evaluates Internet-based asthma interventions that were published between 2004 and October 2014 with respect to the use of behavioral change theoretical frameworks, applied clinical guidelines, and assessment tools.

Methods

The search term (Asthma AND [Online or Internet or Mobile or Application or eHealth or App]) was applied to six bibliographic databases (Ovid MEDLINE, PubMed, BioMed Central, ProQuest Computing, Web of Knowledge, and ACM Digital Library) including only English-language articles published between 2004 and October 2014. In total, 3932 articles matched the priori search terms and were reviewed by the primary reviewer based on their titles, index terms, and abstracts. The matching articles were then screened by the primary reviewer for inclusion or exclusion based on their abstract, study type, and intervention objectives with respect to the full set of priori inclusion and exclusion criteria; 331 duplicates were identified and removed. A total of 85 articles were included for in-depth review and the remaining 3516 articles were excluded. The primary and secondary reviewer independently reviewed the complete content of the 85 included articles to identify the applied behavioral change theories, clinical guidelines, and assessment tools. Findings and any disagreement between reviewers were resolved by in-depth discussion and through a consolidation process for each of the included articles.

Results

The reviewers identified 17 out of 85 interventions (20%) where at least one model, framework, and/or construct of a behavioral change theory were applied. The review identified six clinical guidelines that were applied across 30 of the 85 interventions (35%) as well as a total of 21 assessment tools that were applied across 32 of the 85 interventions (38%).

Conclusions

The findings of this literature review indicate that the majority of published Internet-based interventions do not use any documented behavioral change theory, clinical guidelines, and/or assessment tools to inform their design. Further, it was found that the application of clinical guidelines and assessment tools were more salient across the reviewed interventions. A consequence, as such, is that many Internet-based asthma interventions are designed in an ad hoc manner, without the use of any notable evidence-based theoretical frameworks, clinical guidelines, and/or assessment tools.     

Safety, Complications, and Satisfaction of Patients Undergoing Submuscular Breast Augmentation via the Inframammary and Endoscopic Transaxillary Approach

Background Since its introduction, augmentation mammaplasty has gained widespread popularity, as demonstrated by the fact that an estimated 2 million women in the United States have received implants. During recent decades, several surgical approaches have evolved in terms of implant placement or site of access to the surgical plane. Debate has existed concerning the questionable superiority of a particular technique for achievement of optimal results. Thus, the inframammary approach, an established and widely accepted technique for breast augmentation, and endoscopically assisted transaxillary breast augmentation were retrospectively compared in terms of safety and aesthetic outcome, as measured, respectively, by the rate of postoperative complications and patient satisfaction. Methods This study analyzed 78 patients undergoing augmentation mammaplasty between 1997 and 2004. Only patients seeking primary augmentation mammaplasty solely for aesthetic reasons were included in the study. Previously performed breast surgery and simultaneously conducted ipsilateral mastopexy were among the exclusion criteria. Patient satisfaction was assessed using the client satisfaction questionnaire (CSQ-8) because of its easy applicability. Results The complication rate was low in both patient subsets, thus confirming the safety of the transaxillary approach, as compared with the more common submammary technique. However, a higher level of satisfaction was detected in the former patient group, indicating a more favorable aesthetic outcome with the transaxillary augmentation mammaplasty. Conclusion Endoscopically assisted transaxillary augmentation mammaplasty is a safe method with predictable results associated with a high level of patient satisfaction. If applied in the setting of appropriate indications, it is an excellent tool for use with patients who prefer to have an incision at a distant site.     

Co‐culture of adipose‐derived stem cells and endothelial cells in fibrin induces angiogenesis and vasculogenesis in a chorioallantoic membrane model

Neovascularization of adipose tissue equivalents is a crucial step in successful adipose tissue engineering, since insufficient vascularization results in graft resorption in an in vivo situation. A possible cellular approach to overcome this limitation is the co‐implantation of adipose‐derived stem cells (ASCs) with endothelial cells to stimulate the formation of a vascular network. We investigated the potential of ASCs derived from human abdominal fat tissue co‐cultured with endothelial progenitor cells (EPCs) from human peripheral blood to stimulate neovascularization of fibrin constructs on the chorioallantoic membrane (CAM) of fertilized chicken eggs, in direct comparison to human umbilical vein endothelial cells (HUVECs). After 9 days of incubation, cell–fibrin constructs were explanted and histologically evaluated with respect to ingrowth of avian blood vessels into the construct and formation of human blood vessels by co‐implanted endothelial cells. When administered on the CAM, ASCs successfully guided host vasculature into the construct (angiogenesis) and guided formation of capillary‐like structures by co‐implanted human endothelial cells (vasculogenesis), with HUVECs being superior to EPCs, leading to a perfused avian and human capillary network within the fibrin construct. However, the results also showed that perfused human blood vessels were only observed near the CAM compared to unperfused capillary‐like structures near the top of the construct, indicating that perfusion of the cell–fibrin construct takes longer than 9 days. In conclusion, as blood vessel formation is an essential step during adipogenic differentiation, the data support our hypothesis that cellular communication between transplanted ASCs and endothelial cells is beneficial for vasculogenesis. Copyright © 2013 John Wiley & Sons, Ltd.     

A critical evaluation of the concomitant use of the implantable Doppler probe and the Vacuum Assisted Closure system in free tissue transfer

Introduction of the Vacuum-Assisted Closure (V.A.C.) system has revolutionized the approach to a multitude of clinical settings. Yet, its use precludes adequate clinical monitoring of skin-grafted free flaps, thus, making a reliable monitoring system essential if broad clinical application is aspired. In a clinical study, the usefulness of the combination of the V.A.C. and implantable Doppler probe was critically evaluated in patients with microsurgical lower extremity reconstruction. We retrospectively analyzed the usefulness of the implantable Doppler probe in five consecutive patients treated in our department from January to July 2007. Inclusion criteria were lower extremity reconstruction by means of skin-grafted free tissue transfers with subsequent application of the V.A.C. device. Five consecutive patients (four males, one female) with a mean age of 37.8 years (range, 8-58 years) matched the criteria mentioned above. Of note, the two pediatric patients (8-year-old male and 12-year-old female) suffered from significant posttraumatic stress disorder necessitating concomitant psychological care by the Department of Psychiatry. All flaps healed uneventfully displaying no signs of vascular compromise. Interpretation of the Doppler signal was simple and well received by the nursing staff. The combination of V.A.C. and the implantable Doppler probe enhances patient comfort due to a reduction of the number of dressing changes while still allowing continuous free flap monitoring. Interpretation of the signal transmitted by the probe is simple and potentially reduces misinterpretations due to different levels of experience.