BACKGROUND: Increasing the attractiveness of primary care careers is a key step in addressing the growing shortage of primary care physicians. The purpose of this review was to (1) identify interventions aimed at increasing the proportion of undergraduate medical students choosing a primary care specialty, (2) describe the characteristics of these interventions, (3) assess the quality of the studies, and (4) compare the findings to those of a previous literature review within a global context. METHODS: We searched MEDLINE, EMBASE, ERIC, CINAHL, PsycINFO, The Cochrane Library, and Dissertations & Theses A&I for articles published between 1993 and February 20, 2015. We included quantitative and qualitative studies reporting on primary care specialty choice outcomes of interventions in the undergraduate medical curriculum, without geographic restrictions. Data extracted included study characteristics, intervention details, and relevant outcomes. Studies were assessed for quality and strength of findings using a five-point scale. RESULTS: The review included 72 articles reporting on 66 different interventions. Longitudinal programs were the only intervention consistently associated with an increased proportion of students choosing primary care. Successful interventions were characterized by diverse teaching formats, student selection, and good-quality teaching. Study quality had not improved since recommendations were published in 1995. Many studies used cross-sectional designs and non-validated surveys, did not include control groups, and were not based on a theory or conceptual framework. DISCUSSION: Our review supports the value of longitudinal, multifaceted, primary care programs to increase the proportion of students choosing primary care specialties. Isolated modules or clerkships did not appear to be effective. Our results are in line with the conclusions from previous reviews and add an international perspective, but the evidence is limited by the overall low methodological quality of the included studies. Future research should use more rigorous evaluation methods and include long-term outcomes.

Background Fat grafting is a promising technique for soft-tissue augmentation, although graft retention is highly unpredictable and factors that affect graft survival have not been well defined. Because of their capacity for differentiation and growth factor release, adipose-derived stem cells may have a key role in graft healing. The authors’ objective was to determine whether biological properties of adipose-derived stem cells present within human fat would correlate with in vivo outcomes of graft volume retention. Methods Lipoaspirate from eight human subjects was processed using a standardized centrifugation technique and then injected subcutaneously into the flanks of 6-week-old athymic nude mice. Graft masses and volumes were measured, and histologic evaluation, including CD31+ staining for vessels, was performed 8 weeks after transplantation. Stromal vascular fraction isolated at the time of harvest from each subject was analyzed for surface markers by multi-parameter flow cytometry, and also assessed for proliferation, differentiation capacity, and normoxic/hypoxic vascular endothelial growth factor secretion. Results Wide variation in percentage of CD34+ progenitors within the stromal vascular fraction was noted among subjects and averaged 21.3 ± 15 percent (mean ± SD). Proliferation rates and adipogenic potential among stromal vascular fraction cells demonstrated moderate interpatient variability. In mouse xenograft studies, retention volumes ranged from approximately 36 to 68 percent after 8 weeks, with an overall average of 52 ± 11 percent. A strong correlation (r = 0.78, slope = 0.76, p < 0.05) existed between stromal vascular fraction percentage of CD34+ progenitors and high graft retention. Conclusion Inherent biological differences in adipose tissue exist between patients. In particular, concentration of CD34+ progenitor cells within the stromal vascular fraction may be one of the factors used to predict human fat graft retention. (Plast. Reconstr. Surg. 132: 845, 2013.)