Dispelling the myth that habitual caffeine consumption influences the performance response to acute caffeine supplementation

Objective: To investigate the influence of habitual caffeine intake on aerobic exercise performance responses to acute caffeine supplementation. Methods: A double-blind, crossover, counterbalanced study was performed. Forty male endurance-trained cyclists were allocated into tertiles according to their daily caffeine intake: low (58 ± 29 mg.d-1), moderate (143 ± 25 mg.d-1), and high consumers (351 ± 139 mg.d-1). Participants completed three trials in which they performed simulated cycling time-trials in the fastest time possible following ingestion of: caffeine (CAF: 6 mg.kg-1 BM), placebo (PLA), and no supplement (CON). Results: Mixed-model analysis revealed time-trial performance was significantly improved in CAF compared to PLA and CON (29.92±2.18 min vs 30.81±2.67 and 31.14±2.71 min; P = 0.05). Blood lactate and ratings of perceived exertion were not different between trials and tertiles (P>0.05). Conclusion: Performance effects of acute caffeine supplementation during a ~30 min cycling TT performance were not influenced by the level of habitual caffeine consumption

Mast cell activation in Dowling-Degos disease

Dowling-Degos disease (DDD OMIM 179850) is a rare autosomal-dominant genodermatosis in the spectrum of reticulate pigmented anomalies that usually presents after puberty. It is characterised by reticulate hyperpigmentation and small brownish papules, located at various regions depending on the mutation. Loss-of-function mutations in the genes KRT5, POGLUT1, POFUT1 and PSENEN were identified for DDD. Patients with KRT5 mutations usually develop their lesions at intertriginous areas, whereas patients with POGLUT1 often show affected extremities. Histology reveals downward elongations of rete ridges with a reticulated or fenestrated pattern, occasional horn cysts and basal hyperpigmentation. The phenotype depends on the affected gene. This article is protected by copyright. All rights reserved