Microcirculation : the official journal of the Microcirculatory Society, Inc
-
The standard treatments for venous diseases of the lower limb include compression bandaging and stockings as well as surgical removal of varicose veins. There is a number of conditions in which these conventional treatments are ineffective, particularly in the management of leg ulceration. Drug treatments for healing venous leg ulcers have yet to be developed to the stage of good clinical efficacy, but may assist in the management of patients. ⋯ Work in animal models of ischemia/reperfusion (I/R) show that micronized purified flavonoid fraction (MPFF) modulates leukocyte adhesion and prevents endothelial damage. Similar biochemical effects have been observed in patients with venous disease and may explain the efficacy of this drug in the management of edema and other symptoms of venous disease. There is some evidence that MPFF promotes venous leg ulcer healing.
-
The architecture of the renal medullary microcirculation is highly specialized. Consistent with their role in countercurrent exchange, the vessels (the vasa recta and the intervening capillaries) have high permeabilities to fluid and small hydrophilic solutes. The urea permeability of the continuous endothelium of the descending vasa recta (DVR) in the outer medulla is greatly enhanced by a urea transporter. ⋯ Because the AVR have high Lp's [10(-5) cm s-1 (cm H2O)-1] and are mechanically linked to surrounding structures, small increments of ISF pressures above the pressure within the AVR can drive significant volumes of fluid into AVR if ISF volume expands. The lower reflection coefficients to serum albumin of the AVR as compared with the DVR may be important in the clearance of interstitial plasma protein. Recent work on isolated DVR from the outer medulla has revealed that these vessels are capable of vasoconstriction and thus of regulating medullary blood flow.