Permeability pathophysiological effect

Pathophysiological effects resulting from stimulation of the Hi receptor include those responses seen in immediate allergic reactions, viz, redness, itch, swelling, asthma, anaphylaxis, hron-choconstriction, and vascular permeability. 

LTC4, LTD4 and LTE4 (possibly also the 1 -trans isomers) fulfill two iihportant biological criteria previously attributed to the pathophysiological agent SRS-A, i.e. the potent smooth muscle effects preferentially in peripheral human airways and the marked increase of vascular permeability in the venules. 

The pathophysiology of immune complex reactions occurs in several stages formation of immune complexes in antigen excess, deposition of complexes in tissue, activation of complement followed by attraction at the site of plynuclear neutrophils, and liberation in tissue of proteolytic lysosomal enzymes and inflammatory cationic proteins. The importance of concomitant increase in vascular permeability for the deposition of immune complexes has been shown in vivo by the preventive effect of antihistaminic and antiserotonin drugs on the development of serum sickness to horse antidiphteric serum (Kniker et al. 1971). 

The characteristics of vascular pathophysiology just enumerated, i.e., enhanced extravasation of macromolecular compounds through blood vessels in tumor tissues and the impaired clearance of the macromolecules and lipidic particles from the interstitial space of tumor tissue contributes to the prolonged retention of these drugs in tumor >T27-30 normal tissues, however, the lipid contrast medium Lipiodol and lipids as weU as plasma proteins and macromolecules are cleared from die reticuloendothelial/ lymphatic system To describe this phenomenon related to the fate of macromolecular dmgs and lipids in solid tumor, we coined the term EPR (enhanced permeability and retention) effect in 1984 According... 

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