Patients with heart disease are frequently treated with supplemental oxygen. Although oxygen can exhibit vasoactive properties in many vascular beds, its effects on the coronary circulation have not been fully characterized. To examine whether supplemental oxygen administration affects coronary blood flow (CBF) in a clinical setting, we measured in 18 patients with stable coronary heart disease the effects of breathing 100% oxygen by face mask for 15 min on CBF (via coronary Doppler flow wire), conduit coronary diameter, CBF response to intracoronary infusion of the endothelium-dependent dilator ACh and to the endothelium-independent dilator adenosine, as well as arterial and coronary venous concentrations of the nitric oxide (NO) metabolites nitrotyrosine, NO(2)(-), and NO(3)(-). Relative to breathing room air, breathing of 100% oxygen increased coronary resistance by approximately 40%, decreased CBF by approximately 30%, increased the appearance of nitrotyrosine in coronary venous plasma, and significantly blunted the CBF response to ACh. Oxygen breathing elicited these changes without affecting the diameter of large-conduit coronary arteries, coronary venous concentrations of NO(2)(-) and NO(3)(-), or the coronary vasodilator response to adenosine. Administering supplemental oxygen to patients undergoing cardiac catheterization substantially increases coronary vascular resistance by a mechanism that may involve oxidative quenching of NO within the coronary microcirculation.

Pathological formation of reactive oxygen species within the coronary circulation has been hypothesized to mediate some clinical manifestations of ischemic heart disease (IHD) by interfering with physiological regulation of coronary tone. To determine the degree to which coronary tone responds to acute changes in ambient levels of oxidants and antioxidants in vivo in a clinical setting, we measured the effect of an acute oxidative stress (breathing 100% oxygen) on coronary capacitance artery diameter (quantitative angiography) and blood flow velocity through the coronary microcirculation (intracoronary Doppler ultrasonography) before and after treatment with the antioxidant vitamin C (3-g intravenous infusion) in 12 IHD patients undergoing a clinical coronary interventional procedure. Relative to room air breathing, 100% oxygen breathing promptly reduced coronary blood flow velocity by 20% and increased coronary resistance by 23%, without significantly changing the diameter of capacitance arteries. Vitamin C administration promptly restored coronary flow velocity and resistance to a slightly suprabasal level, and it prevented the reinduction of coronary constriction with rechallenge with 100% oxygen. This suggests that acute oxidative stress produces prompt and substantial changes in coronary resistance and blood flow in a clinical setting in patients with IHD, and it suggests that these changes are mediated by vitamin C-quenchable substances acting on the coronary microcirculation. This observation may have relevance for clinical practice.

The Neolithization of Northern Eurasia is marked by the emergence of pottery among hunter-gatherer societies. The driving forces behind the adoption of ceramic cooking vessels among non-agricultural societies remain unclear, although previous research, mainly in North East Asia (e.g. Japan, Korea and the Russian Far East), suggests that it was adopted as a specialist technology for processing aquatic resources, linked to the intensification of fishing activities and a move to sedentism. The stratified site of Zamostje 2 in the forest zone of the Volga-Oka region includes both aceramic Mesolithic and two early ceramic horizons dating to Early Neolithic (EN) and Middle Neolithic (MN). This provides a unique opportunity to look at the impacts of the adoption of pottery on the wider economy and determine whether pottery function changes over time. This was achieved through the analysis of lipids from 166 potsherds dating from the earliest phases (mid-6th millennium cal BC) to the MN (5th millennium cal BC). Contrary to our expectations, the pottery from the EN phase was used to process a broad range of foodstuffs including terrestrial resources, such as forest fruits, in addition to freshwater fish. In contrast, pottery from the MN phase was used exclusively for processing aquatic resources. The results show that in this case, pottery was adopted as a more general-purpose cooking container, at least in the earliest phases of use, and that a specialist function only emerged later. Introduction: Hunter-gatherers pottery and Neolithization of Northern EurasiaArchaeologists now acknowledge two contrasting processes of Neolithization. The classic definition of the Neolithic arose in Western Europe and involved the emergence of farming in the Near East, and the dispersal of a package of innovations including domestic crops and animals, village life and pottery into Northwest Europe. In contrast, archaeologists working in other parts of Eurasia define the onset of the Neolithic by the emergence of pottery cooking containers among hunter-gatherer societies, along with an increase in sedentism, emergence of new subsistence strategies with food storage and fishing intensification, and settlement at strategic locations giving access to a

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