An enigma in the genetic responses of plants to salt stresses

Soil salinity is one of the main factors restricting crop production throughout the world. Various salt tolerance traits and the genes controlling these traits are responsible for coping with salinity stress in plants. These coping mechanisms include osmotic tolerance, ion exclusion, and tissue tolerance. Plants exposed to salinity stress sense the stress conditions, convey specific stimuli signals, and initiate responses against stress through the activation of tolerance mechanisms that include multiple genes and pathways. Advances in our understanding of the genetic responses of plants to salinity and their connections with yield improvement are essential for attaining sustainable agriculture. Although a wide range of studies have been conducted that demonstrate genetic variations in response to salinity stress, numerous questions need to be answered to fully understand plant tolerance to salt stress. This chapter provides an overview of previous studies on the genetic control of salinity stress in plants, including signaling, tolerance mechanisms, and the genes, pathways, and epigenetic regulators necessary for plant salinity tolerance

Effects of Shear Forces and Pressure on Blood Vessel Function and Metabolism in a Perfusion Bioreactor.

Bovine saphenous veins (BSV) were incubated in a perfusion bioreactor to study vessel wall metabolism and wall structure under tissue engineering conditions. Group 1 vessels were perfused for 4 or 8 days. The viscosity of the medium was increased to that of blood in group 2. Group 3 vessels were additionally strained with luminal pressure. Groups 1-d through 3-d were similar except that BSV were endothelium-denuded before perfusion. Groups 1-a through 3-a used native vessels at elevated flow rates. Group 3 vessels responded significantly better to noradrenaline on day 4, whereas denuded vessels showed attenuated responses (p < 0.001). Tetrazolium dye reduction did not depend on perfusion conditions or time except for denuded vessels. pO(2) gradients across the vessels were independent of time and significantly higher in group 2 (p < 0.001). BSV converted glucose stoichiometrically to lactate except vessels of groups 3, 1-d, and 3-d which released more lactate than glucose could supply (p < 0.001). Group 1 vessels as well as all vessels perfused with elevated flow rates showed a loss of endothelial cells after 4 days, whereas group 2 and 3 vessels retained most of the endothelium. These data suggest that vessel metabolism was not limited by oxygen supply. Shear forces did not affect glucose metabolism but increased oxygen consumption and endothelial cell survival. Luminal pressure caused the utilization of energy sources other than glucose, as long as the endothelium was intact. Therefore, vessel metabolism needs to be monitored during tissue engineering procedures which challenge the constructs with mechanical stimuli

Results of mechanical circulatory support in France.

OBJECTIVE: To present the analyzed results on mechanical circulatory support (MCS) collected over a 7-year period, from 2000 to 2006, in France. METHODS: A cohort of 520 patients was analyzed. Mean age was 43.7 \ub1 13.6 years. The main causes of cardiac failure were ischemic cardiomyopathy (39%), idiopathic dilated cardiomyopathy (41.3%), or myocarditis (6.4%). Bridge to transplantation was indicated in 87.8% of patients, bridge to recovery in 9%, while destination therapy was proposed in 3.2% of patients. RESULTS: For patients in cardiogenic shock or advanced heart failure undergoing device implantation as bridge to transplantation or recovery (n=458), overall mortality was 39% (n=179). The main causes of mortality under MCS were multi-organ failure (MOF) (57.4%), neurological events (14.1%), or infections (11.9%). Heart transplantation was performed in 249 (54.3%) patients. The main causes of death following heart transplantation were primary graft failure (22.4%), MOF (14.3%), neurological event (14.3%), or infection (10.2%). Long-term survival in transplanted patients was 75 \ub1 2.8% at 1 year and 66 \ub1 3.4% at 5 years. CONCLUSIONS: MCS is an essential therapeutic tool to save the life of young patients with cardiogenic shock or advanced cardiac failure. Early MCS implantation and the availability of a device that is adapted to the patient's clinical status are prerequisites for reducing overall mortality rates