Factors Associated With Resident Research Success: An Analysis of Canadian General Surgery Trainees.

OBJECTIVE: Better understanding the research productivity of Canadian general surgery residents and factors associated with success would provide a valuable reference and help inform actions to enable success. We aimed to characterize the research productivity of Canadian general surgery residents and to evaluate factors associated with residents' research quantity and impact. DESIGN: A cross-sectional, observational study was performed using publicly available data evaluating Canadian General Surgery resident research productivity. Research productivity was characterized using measures including publications per postgraduate year (PGY) and CiteScore among others. Residency programs were then comparatively assessed using a multivariable logistic regression to evaluate program and resident factors associated with achieving >50th percentile research productivity. SETTING AND PARTICIPANTS: All General Surgery residents from English speaking Canadian training programs were included in this study, which was completed at the University of Alberta, a tertiary level academic center in Edmonton, Canada. RESULTS: A wide range of resident research productivity was observed across Canada with the median publications per PGY of 0.29, and the median sum of a resident's publication CiteScores of 2.05. The median h-index was 0.90. Graduate degree completion and publication experience prior to residency were significantly associated with higher publications per PGY (OR 2.94 and OR 2.10, respectively), as well as higher mean CiteScore (OR 3.42 and 2.24). The program factors that were assessed, including program size, research blocks, mandatory projects, or higher staff research productivity, did not show significant association with increased research output. CONCLUSIONS: There is a wide range in research output by general surgery residents across the country. Successful completion of graduate degrees and the experience of publication prior to residency are associated with higher research productivity and impact.

Sphingolipid Modulation Activates Proteostasis Programs to Govern Human Hematopoietic Stem Cell Self-Renewal.

Cellular stress responses serve as crucial decision points balancing persistence or culling of hematopoietic stem cells (HSCs) for lifelong blood production. Although strong stressors cull HSCs, the linkage between stress programs and self-renewal properties that underlie human HSC maintenance remains unknown, particularly at quiescence exit when HSCs must also dynamically shift metabolic state. Here, we demonstrate distinct wiring of the sphingolipidome across the human hematopoietic hierarchy and find that genetic or pharmacologic modulation of the sphingolipid enzyme DEGS1 regulates lineage differentiation. Inhibition of DEGS1 in hematopoietic stem and progenitor cells during the transition from quiescence to cellular activation with N-(4-hydroxyphenyl) retinamide activates coordinated stress pathways that coalesce on endoplasmic reticulum stress and autophagy programs to maintain immunophenotypic and functional HSCs. Thus, our work identifies a linkage between sphingolipid metabolism, proteostatic quality control systems, and HSC self-renewal and provides therapeutic targets for improving HSC-based cellular therapeutics.

Leukotriene B4-Mediated Neutrophil Recruitment Causes Pulmonary Capillaritis during Lethal Fungal Sepsis.

Candida albicans bloodstream infection causes fungal septicaemia and death in over half of afflicted patients. Polymorphonuclear leukocytes (PMN) mediate defense against invasive candidiasis, but their role in protection versus tissue injury and sepsis is unclear. We observe PMN intravascular swarming and subsequent clustering in response to C. albicans yeast in a lethal septic mouse and human pulmonary circulation model. Live C. albicans sequester to the endothelium and are immediately captured by complement-dependent PMN chemotaxis, which is required for host survival. However, complement activation also leads to Leukotriene B4 (LTB4)-mediated intravascular PMN clustering and occlusion, resulting in capillaritis with pulmonary hemorrhage and hypoxemia. This clustering is unique to fungi and triggered by fungal cell wall components. PMN clustering is absent in mice lacking LTB4-receptor, and capillaritis is attenuated upon pharmacological LTB4 blockade without affecting phagocytosis. Therefore, therapeutically disrupting infection-induced capillaritis may limit organ injury without impairing host defense during fungal sepsis.

Aged polymorphonuclear leukocytes cause fibrotic interstitial lung disease in the absence of regulation by B cells.

Pulmonary immunity requires tight regulation, as interstitial inflammation can compromise gas exchange and lead to respiratory failure. Here we found a greater number of aged CD11bhiL-selectinloCXCR4+ polymorphonuclear leukocytes (PMNs) in lung vasculature than in the peripheral circulation. Using pulmonary intravital microscopy, we observed lung PMNs physically interacting with B cells via ß2 integrins; this initiated neutrophil apoptosis, which led to macrophage-mediated clearance. Genetic deletion of B cells led to the accumulation of aged PMNs in the lungs without systemic inflammation, which caused pathological fibrotic interstitial lung disease that was attenuated by the adoptive transfer of B cells or depletion of PMNs. Thus, the lungs are an intermediary niche in the PMN lifecycle wherein aged PMNs are regulated by B cells, which restrains their potential to cause pulmonary pathology.

High prevalence of potential drug-drug interactions in patients with castration-resistant prostate cancer treated with abiraterone acetate.

PURPOSE: Abiraterone acetate (AA), used to treat metastatic castration-resistant prostate cancer (mCRPC), inhibits androgen biosynthesis by blocking cytochrome P450 (CYP) 17A1. It also inhibits other cytochromes involved in the metabolism of various widely used medications. As such, there is presumably a high potential for drug-drug interactions (DDIs) that can diminish the efficacy of AA or concurrent medications, or increase the risk of DDI-related adverse events (AEs). However, the scale of AA-associated DDIs is currently unknown. METHODS: We conducted a retrospective review of pharmacy records and electronic patient charts to retrieve individual drug histories and on-treatment AEs of mCRPC patients beginning AA therapy in a tertiary care setting. Potential DDIs were analyzed using two commercial databases, Lexicomp and Micromedex. RESULTS: Eighty-four informative patients were identified. Sixty-five patients (77 %) and 44 patients (52 %) were flagged for one or more potential DDIs by the Lexicomp and Micromedex databases, respectively. One hundred eighty-four potential DDIs were identified overall, with a median of 1 DDI per patient in both databases. Possibly due to rigorous DDI screening before AA treatment initiation, we did not identify a definite instance of DDI-related AEs. CONCLUSIONS: The use of commercial DDI databases suggests a substantial risk of potentially consequential DDIs in mCRPC patients undergoing AA therapy. However, prospective investigations with larger patient populations are required to better establish the clinical relevance of these DDIs.

Cost-effectiveness of prophylactic granulocyte colony-stimulating factor for febrile neutropenia in breast cancer patients receiving FEC-D.

5-fluorouracil, epirubicin, cyclophosphamide â†’ docetaxel (FEC-D) has been associated with higher-than-expected rates of febrile neutropenia (FN) that meet the current guideline threshold of 20 % for primary prophylaxis (PP) with granulocyte colony-stimulating factor (G-CSF). We examined the cost-effectiveness of FEC-D with varying strategies of G-CSF prophylaxis from the perspective of the public payer in Ontario, Canada. A state-transition model was developed to compare three strategies: FEC-D with secondary prophylaxis (SP) only, PP starting with the first cycle of D, and PP starting with the first cycle of FEC. Analysis was conducted for a hypothetical cohort of 50-year-old early-stage breast cancer patients undergoing adjuvant chemotherapy, at a 10-year horizon. Results were expressed in quality-adjusted life-years (QALYs) and 2013 Canadian dollars. Costs and benefits were discounted at 5 %. Event rates, costs, and utilities were derived from the literature. One-way and probabilistic sensitivity analyses were conducted. Using filgrastim, the incremental cost-effectiveness ratios (ICERs) for starting PP with the first cycle of D and starting PP with the first cycle of FEC, compared to using SP only, were $57,886/QALY and $116,186/QALY, respectively. With pegfilgrastim, the ICERs for the same strategies were $90,735/QALY and $149,483/QALY. Compared to using filgrastim SP only, starting PP with D had a 24 % chance of being cost-effective at a willingness-to-pay (WTP) threshold of $50,000/QALY, and a 99 % chance at a WTP threshold of $100,000/QALY. Results were sensitive to FN-related parameters, such as the risk of FN per cycle with D and the associated mortality, but were robust to uncertainty in parameters related to breast cancer, such as the utilities and hazard of relapse. FEC-D with PP starting with the first cycle of D is most likely to be cost-effective, especially with increased risk of FN and mortality from FN.

A systematic literature analysis of correlative studies in low-dose metronomic chemotherapy trials.

Low-dose metronomic (LDM) chemotherapy is a beneficial and very well-tolerated form of chemotherapy utilization characterized by the frequent and uninterrupted administration of low doses of conventional chemotherapeutic agents over prolonged periods of time. While patients resistant to standard maximum tolerated dose (MTD) chemotherapy may still benefit from LDM chemotherapy, there is a lack of predictive markers of response to LDM chemotherapy. We searched the MEDLINE, EMBASE, CENTRAL and PubMed databases for correlative studies conducted as part of LDM chemotherapy trials in order to identify the most promising biomarker candidates. Given the antiangiogenic properties of LDM chemotherapy, angiogenesis-related biomarkers were most commonly studied. However, significant correlations between angiogenesis-related biomarkers and study end points were rare and variable, even so far as biomarkers correlating positively with an end point in some studies and negatively with the same end point in other studies. Pursuing biomarkers outside the angiogenesis field may be more promising.

FGF23: mediator of poor prognosis in a sizeable subgroup of patients with castration-resistant prostate cancer presenting with severe hypophosphatemia?

Castration-resistant prostate cancer (CRPC) is an advanced and incurable stage of the second most frequently diagnosed malignancy in men globally. Current treatment options improve survival modestly but eventually fail due to intrinsic or acquired therapeutic resistance. A hypothesis is presented wherein circulating levels of fibroblast growth factor 23 (FGF23), an endocrine member of the fibroblast growth factor family with phosphaturic properties, are proposed as a prognostic and predictive marker to identify CRPC patients with poor prognosis that are amenable to FGF23 antibody therapy (FGF23i) or treatment with fibroblast growth factor receptor inhibitors (FGFRi). With respect to the latter, FGF23 may also serve as a pharmacodynamic marker enabling individualized FGFRi dosing. We recently discovered that the development of severe and sustained hypophosphatemia in CRPC patients undergoing zoledronic acid therapy for bone metastases was associated with markedly worse prognosis compared to patients without or with only mild and transient hypophosphatemia. Severe hypophosphatemia is a typical manifestation of tumor-induced hypophosphatemic osteomalacia (TIO), a paraneoplastic condition mediated by FGF23 overexpression in most instances. While the postulated tumor-promoting role of FGF23 in CRPC or other malignancies has not yet been studied, several lines of evidence suggest that FGF23 may mediate both severe hypophosphatemia (via its endocrine properties) and aggressive CRPC behavior (via autocrine and paracrine activities): (i) FGF23 and the necessary signalling machinery (i.e. members of the fibroblast growth factor receptor [FGFR] family and the essential co-receptor α-KLOTHO [KL]) are highly expressed in a sizeable subgroup of CRPC patients; (ii) FGF/FGFR signalling plays important roles in prostate cancer; (iii) FGF23 can induce its own expression via a positive autocrine feedback loop involving FGFR1; and (iv) this positive feedback loop may be triggered by bone-targeted therapies frequently used for the treatment of CRPC-associated bone metastases. While there is a lack of personalized treatment strategies in the management of CRPC to date, FGF23 targeted therapy has the potential to fill this unmet clinical need in the not-so-distant future. In fact, FGFRi are currently in advanced clinical testing for a number of malignancies such as kidney and lung cancer, but there is a lack of conclusive data on FGFRi therapy in patients selected for FGF/FGFR pathway activation.