Epigenetic patterns in Atlantic herring (Clupea harengus): Temperature and photoperiod as environmental stressors during larval development

Understanding the molecular mechanisms underlying individual responses to environmental changes is crucial for species conservation and management. Pelagic fishes including Atlantic herring (Clupea harengus) are of particular interest because of their key ecological and economic roles and their susceptibility to a changing ocean from global warming. Temperature and photoperiod have been linked with spawning time and location in adult herring, but no study has thus far investigated the role of environmental factors on gene regulation during the vulnerable early developmental stages. Here, we examine DNA methylation patterns of larval herring bred under two temperatures (11°C and 13°C) and photoperiod (6 and 12 h) regimes in a 2 × 2 factorial design. We found consistently high levels of global methylation across all individuals and a decline in global methylation with increased developmental stage that was more pronounced at 13°C (p ≤ 0.007) than at 11°C (p ≥ 0.21). Most of the differentially methylated sites were in exon and promoter regions for genes linked to metabolism and development, some of which were hypermethylated at higher temperature. These results demonstrate the important role of DNA methylation during larval development and suggest that this molecular mechanism might be key in regulating early-stage responses to environmental stressors in Atlantic herring.

Identifying Barriers in Access to Care for Head and Neck Cancer Patients: A Field Study in Dakar

OBJECTIVES/HYPOTHESIS

To identify barriers in access to care for head and neck cancer (H&NC) patients in low- and middle-income countries (LMICs), specifically within Dakar, Senegal, using both quantitative and qualitative data.

STUDY DESIGN

Descriptive observational study.

METHODS

Patients with H&NC were selected from two independent university hospitals in Dakar, Senegal. A mixed-methods descriptive study was performed using a specifically tailored questionnaire and a focused ethnographic qualitative approach to identify factors that delay patient presentation, referral, and treatment. Quantitative data were analyzed using descriptive statistics and qualitative using a deductive approach based on a systematic review of the literature.

RESULTS

Thirty-three patients with a mean age of 57.8 years were included. Presentation delay was 5.7 months, mainly attributed to cost of consultation (39%), waiting time at doctor's office (15%), and distance to healthcare facility (12%). Referral delay greater than 3 months was observed in 60% of participants, secondary to misdiagnosis and lack of appropriate referral. Treatment delay was associated with limited local treatment capacity and securing cost of treatment. Cost of transportation impacted all delays.

CONCLUSIONS

This work used an evidence-based approach to identify barriers in access to care for H&NC patients in sub-Saharan Africa. It suggests the feasibility and transferability of this methodology which combined a quantitative approach based on the literature with a qualitative analysis. Insight provided by this study will be used to guide development of implementation strategies for early detection of H&NC in LMICs.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Women in Medicine: Dr. Louise Pilote

Always driven by a desire to understand, Dr. Louise Pilote (MDCM, MPH, PhD, FRCPC) can accurately be described as a lifelong learner. As the former Director of the Division of General Internal Medicine at McGill University, this clinician scientist is a Professor of Medicine at McGill and holds a James McGill chair. Her research interests include cardiovascular disease, specifically in women, as well as health service outcomes. Pilote’s most recent endeavor focuses on the impact of gender on health outcomes, on a globalized scale. Now a mother of five, Pilote shares her experience with infertility and how to integrate professional and personal life. She also discusses the intersection of medicine and feminism, while providing advice for the next wave of clinician researchers.