Endothelin-1 stimulates neutrophil adhesion to endothelial cells by an effect on the expression of adhesive molecules on the neutrophil surface. Endothelin-1 stimulates neutrophil accumulation in vivo and in vitro in the heart. Antibodies against the integrin complex block the endothelin-1-dependent neutrophil adhesion. These findings have potential importance in the pathophysiology of endothelin-1-increased states.
The nitric oxide pathway is upregulated in the resistance circulation and the heart of the spontaneously hypertensive rat by a mechanism involving induction of the constitutive nitric oxide synthase and overproduction of nitric oxide. However, nitric oxide is not sufficiently bioactive to stimulate the formation of cyclic GMP and to maintain an adequate nitric oxide-dependent vasodilatory tone.
Permixon increased molecular markers involved in the apoptotic process, ie the Bax-to-Bcl-2 expression ratio and caspase-3 activity. This could have clinical relevance due to the improvement in symptoms produced by treatment with this drug.
Abstract-Heart failure is characterized by neurohumoral alterations, such as activation of the sympathetic nervous system, stimulation of the renin-angiotensin system, increased activity of the endothelin system, increased production of norepinephrine, and increased circulating levels of cytokines. Oxidative stress is associated with the formation of reactive oxygen species (ROS). The myocardium has enzymes that stimulate ROS generation and enzymes with antioxidant effects. Several studies have suggested that ROS are increased in the failing heart. ROS may contribute to the pathophysiology of heart failure by initiating myocyte apoptosis and exerting direct negatively inotropic effects through the reduction of cytosolic intracellular free calcium. However, mechanisms such as endothelial dysfunction and inflammation have also been involved in the progression of heart failure. Antioxidants (eg, vitamin C) seem to improve endothelial functionality and reduce the inflammatory response in patients with heart failure. Therefore, in this review, we analyzed the involvement of ROS in the cellular and molecular mechanisms associated with endothelial dysfunction in heart failure.
Mutation of the K-ras gene is thought to be an early and important event in pancreatic carcinogenesis. In order to study the role of this molecular alteration in the transition from the normal to the neoplastic pancreatic cell, bovine pancreatic duct cells were first immortalized by SV40 large T antigen (Ag) complementary (c)DNA transfection and then transfected with a mutated K-ras gene. As did primary duct cells, the immortalized duct cells (more than 100 passages) expressed cytokeratins, carbonic anhydrase type-II, cystic fibrosis transmembrane conductance regulator (CFTR), and multidrug resistance (mdr). They grew as a single layer after transplantation under plastic domes and formed three-dimensional structures resembling ducts when grown on Matrigel. Cell growth was stimulated by insulin, epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, but cells did not respond to gastrin and CCK-8. They did not form colonies in soft agar nor did they form tumors in nude mice. Immortalized cells transfected with mutated K-ras acquired the ability to form tumors after orthotopic injection into the nude mouse pancreas. It is concluded that SV 40 immortalized bovine pancreatic
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