Tissue underlying the intestinal epithelium elicits proliferation of intestinal stem cells following cytotoxic damage.

The goals of this study were to document the proliferative response of intestinal stem cells (ISCs) during regeneration after damage from doxorubicin (DXR), and to characterize the signals responsible for ISC activation. To this end, jejuni from DXR-treated mice were harvested for histology, assessment of ISC numbers and proliferation by flow cytometry, crypt culture, and RNA analyses. Histology showed that crypt depth and width were increased 4 days after DXR. At this time point, flow cytometry on tissue collected 1 h after EdU administration revealed increased numbers of CD24(lo)UEA(-) ISCs and increased percentage of ISCs cycling. In culture, crypts harvested from DXR-treated mice were equally proliferative as those of control mice. Addition of subepithelial intestinal tissue (SET) collected 4 days after DXR elicited increased budding (1.4 ± 0.3 vs. 5.1 ± 1.0 buds per enteroid). Microarray analysis of SET collected 4 days after DXR revealed 1030 differentially expressed transcripts. Cross-comparison of Gene Ontology terms considered relevant to ISC activation pointed to 10 candidate genes. Of these, the epidermal growth factor (EGF) family member amphiregulin and the BMP antagonist chordin-like 2 were chosen for further study. In crypt culture, amphiregulin alone did not elicit significant budding, but amphiregulin in combination with BMP antagonism showed marked synergism (yielding 6.3 ± 0.5 buds per enteroid). These data suggest a critical role for underlying tissue in regulating ISC behavior after damage, and point to synergism between amphiregulin and chordin-like 2 as factors which may account for activation of ISCs in the regenerative phase.

Impact of Early Exposure to Robotic Surgery Among Pre-clinical Medical Students on Career Choice and Simulation Skills.

We aimed to assess whether early exposure of medical students to robotic surgery training influences their interest in a surgical career and improves scores on objective simulation tasks. Medical students were invited to participate in robotic online training modules, robotic simulation exercises followed by a hands-on robotic dry-lab session. Pre- and post-simulator scores were recorded. A 29-question anonymous survey was recorded before and after the lab. Seventy percent reported that the training had a positive impact on influencing their decision to pursue a general surgery career. Students showed significantly improved skill and performance on simulation activities post-training. After the training, students felt knowledgeable about robotics, more comfortable operating robotically, and thought that robotic surgery would hold a significant place in the future of surgery. Exposing students to robotic training positively impacts their perception of surgery as a career choice and results in improvement in objective scores on simulation tasks.

Does Intentional Support of Degree Programs in General Surgery Residency Affect Research Productivity or Pursuit of Academic Surgery? A Multi-Institutional Study.

OBJECTIVE: To determine whether pursuit of an advanced degree during dedicated research time (DRT) in a general surgery residency training program impacts a resident's research productivity. DESIGN: A retrospective, multi-institutional cohort study. SETTING: General surgery residency programs that were approved to graduate more than 5 categorical residents per year and that offered at least 1 year of DRT were contacted for participation in the study. A total of 10 general surgery residency programs agreed to participate in the study. PARTICIPANTS: Residents who started their residency between 2000 and 2012 and spent at least one full year in DRT (n = 511) were included. Those who completed an advanced degree were compared on the following parameters to those who did not complete one: total number of papers, first-author papers, the Journal Citation Reports impact factors of publication (2018, or most recent), and first position after residency or fellowship training. RESULTS: During DRT, 87 (17%) residents obtained an advanced degree. The most common degree obtained was a Master of Public Health (MPH, n = 42 (48.8%)). Residents who did not obtain an advanced degree during DRT published fewer papers (median 8, [interquartile range 4-12]) than those who obtained a degree (9, [6-17]) (p = 0.002). They also published fewer first author papers (3, [2-6]) vs (5, [2-9]) (p = 0.002) than those who obtained a degree. Resident impact factor (RIF) was calculated using Journal Citation Reports impact factor and author position. Those who did not earn an advanced degree had a lower RIF (adjusted RIF, 84 ± 4 vs 134 ± 5, p < 0.001) compared to those who did. There was no association between obtaining a degree and pursuit of academic surgery (p = 0.13) CONCLUSIONS: Pursuit of an advanced degree during DRT is associated with increased research productivity but is not associated with pursuit of an academic career.