Purinergic signalling and immune cells

This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells

FREQUENCY AND SEVERITY OF CYCLIC FLOW ALTERNATIONS AND PLATELET-AGGREGATION PREDICT THE SEVERITY OF NEOINTIMAL PROLIFERATION FOLLOWING EXPERIMENTAL CORONARY STENOSIS AND ENDOTHELIAL INJURY

The role of recurrent platelet aggregation in the development of neointimal proliferation of coronary arteries was explored in this study, and the hypothesis was evaluated that recurrent platelet aggregation and the consequent frequency and severity of cyclic coronary blood flow variations are important pathophysiologic factors in the subsequent development of neointimal proliferation. In 24 chronically instrumented dogs, variable degrees of coronary artery neointimal proliferation were observed 3 weeks after mechanical injury of the arterial endothelium and the placement of an external coronary artery constrictor. The severity of neointimal proliferation at 21 days was closely related to the frequency and severity of cyclic coronary blood flow variations during the initial 7 days after instrumentation of the animals, itself a manifestation of recurrent platelet aggregation and dislodgement. Pharmacological therapy with a dual thromboxane A2 synthetase inhibitor and receptor antagonist and with a serotonin S2 receptor antagonist frequently was successful in abolishing cyclic blood flow variations and in retarding neointimal proliferation

Natural antibacterial agents from arid-region pretreated lignocellulosic biomasses and extracts for the control of lactic acid bacteria in yeast fermentation

Bacterial contamination is one of the major challenges faced by yeast fermentation industries as the contaminating microorganisms produce lactic acid and acetic acid, which reduces the viability of yeast, and hence fermentation yields. The primary bacterial contaminants of yeast fermentations are lactic acid bacteria (LAB). This study aims to identify potential natural antibacterial fractions from raw and pretreated lignocellulosic biomasses found in Abu Dhabi, UAE, in terms of LAB inhibition capacity, allowing growth of the yeast. The analysis was carried out using plating technique. Pretreatment liquid of the mangrove stem Avicennia marina hydrothermally pretreated at 210 °C exhibited the widest inhibition zone with an average diameter of 14.5 mm, followed by the pretreatment liquid of mangrove leaf pretreated at 190 °C, Salicornia bigelovii pretreated at 202 °C and rachis of date palm Phoenix dactylifera pretreated at 200 °C. The compounds responsible for the antibacterial activity will be characterized in further study