Reducing unpleasant side effects of topical 5-Fluorouracil treatment for actinic keratosis: a randomized controlled trial.

Introduction: 5-Fluorouracil (5-FU) for prophylactic treatment of diffuse actinic keratosis results in an exuberant inflammatory reaction, contributing to patient noncompliance and dissatisfaction.Design: This 5-week split-faced, double-blind, randomized controlled trial involved 30 subjects with diffuse facial AK who received twice daily 5-FU treatment for 2 weeks. This was followed by pre-randomized twice daily use of one of three topical interventions on one half of the face. TEWL, pH, and hydration were assessed on each quadrant of the face at all visits. Additionally, photographs were subjectively graded by three blinded trained observers.Results: Thirty subjects were enrolled, and had an average 27.1 (SD 11.8, range: 13-62) palpable AKs at baseline. Average resolution of baseline AK count was 98.1% by week 4. Clobetasol propionate is best at decreasing TEWL (p = .034), while petrolatum jelly most significantly improves hydration (p = .019) and erythema (p = .014). Though controlled release skin barrier emulsion trended towards improvement in TEWL (p = .17) and hydration (p = .19), there was no significant decrease in erythema (p = .257). Patient free-text response identified erythema as the most bothersome symptom.Conclusions: Given the low cost, wide availability, and ability to significantly reduce erythema, petrolatum should be used for post-5-FU treatment for diffuse AK.

Vagal Mediation of Low-Frequency Heart Rate Variability During Slow Yogic Breathing.

OBJECTIVE: Changes in heart rate variability (HRV) associated with breathing (respiratory sinus arrhythmia) are known to be parasympathetically (vagally) mediated when the breathing rate is within the typical frequency range (9-24 breaths per minute [bpm]; high-frequency HRV). Slow yogic breathing occurs at rates below this range and increases low-frequency HRV power, which may additionally reflect a significant sympathetic component. Yogic breathing techniques are hypothesized to confer health benefits by increasing cardiac vagal control, but increases in low-frequency HRV power cannot unambiguously distinguish sympathetic from parasympathetic contributions. The aim of this study was to investigate the autonomic origins of changes in low-frequency HRV power due to slow-paced breathing. METHODS: Six healthy young adults completed slow-paced breathing with a cadence derived from yogic breathing patterns. The paced breathing took place under conditions of sympathetic blockade, parasympathetic (vagal) blockade, and placebo. HRV spectral power was compared under 11 breathing rates during each session, in counterbalanced order with frequencies spanning the low-frequency range (4-9 bpm). RESULTS: HRV power across the low-frequency range (4-9 bpm) was nearly eliminated (p = .016) by parasympathetic blockade (mean (SD) spectral power at breathing frequency = 4.1 (2.1)) compared with placebo (69.5 (8.1)). In contrast, spectral power during sympathetic blockade 70.2 (9.1) and placebo (69.5 (8.1)) was statistically indistinguishable (p = .671). CONCLUSIONS: These findings clarify the interpretation of changes in HRV that occur during slow-paced breathing by showing that changes in low-frequency power under these conditions are almost entirely vagally mediated. Slow-paced breathing is an effective tool for cardiac vagal activation.