https://www.selleckchem.com/products/asn007.html jor open questions in this field, we close by suggesting how to begin answering them in clinically relevant, currently available preclinical in situ research models.A patient presented with a 3-month history of a rapidly enlarging ulcerated tumour on his lower leg, occurring on a background of chronic idiopathic lymphoedema of approximately 10 years' duration. Histology revealed extensive infiltration of the dermis by a vascular tumour with pleomorphic and hyperchromatic endothelial cells, which stained positive for vascular markers CD31, CD34 and ERG. A diagnosis of lymphoedema-associated angiosarcoma was reached and our patient was treated with isolated limb perfusion with high-dose melphalan and tumour necrosis factor-alfa.The daily rhythm of plasma melatonin concentrations is typically unimodal, with one broad peak during the circadian night and near-undetectable levels during the circadian day. Light at night acutely suppresses melatonin secretion and phase shifts its endogenous circadian rhythm. In contrast, exposure to darkness during the circadian day has not generally been reported to increase circulating melatonin concentrations acutely. Here, in a highly-controlled simulated night shift protocol with 12-h inverted behavioral/environmental cycles, we unexpectedly found that circulating melatonin levels were significantly increased during daytime sleep (p  less then  .0001). This resulted in a secondary melatonin peak during the circadian day in addition to the primary peak during the circadian night, when sleep occurred during the circadian day following an overnight shift. This distinctive diurnal melatonin rhythm with antiphasic peaks could not be readily anticipated from the behavioral/environmental factors in the proactor(s) driving the unexpected daytime melatonin secretion and the melatonin rhythm with antiphasic peaks during shifted sleep/wake schedules, the underlying mechanisms of their relationship