Seasonal Effects on Human Physiological Adaptation Factors, Thermotolerance andPlasma Fibronectin

摘要

A large molecular weight (440 kilodalton) protein, known as plasma fibronectin(PF), facilitates reticuloendothelial system (RES) clearance of blood-borne particles such as tissue debris, fibrin clots and bacteria. With rare exception, PF level correlates with RES clearance capacity. Clearance of vascular debris in the support of blood vessel patency may explain, in part, the association of increased shock survival with elevated RES function. Vascular shock can result in a reduced RES clearance capacity and suppressed PF levels. Human patients who succumb to the effects of shock have sustained suppression of PF level, while those who survive experience a rapid recovery in PF concentration. PF replacement improves septic-surgical and trauma patient health. Rats are more sensitive to traumatic shock and experience RES suppression following treatment with antibodies to PF. Together these findings indicate that RES clearance and PF influence the outcome of shock. Moreover, stimulation of RES clearance in rats significantly reduces mortality induced by exposure to excessive heat and heat shock mortality is reduced in rats that have a naturally elevated PF level. Such findings suggest a relationship between PF and heat stress survival in animals.