Publications [#134180] of Mark W. Dewhirst

Papers Published

1. JC Acker, LB Marks, DP Spencer, W Yang, MA Avery, RK Dodge, GL Rosner, MW Dewhirst, Serial in vivo observations of cerebral vasculature after treatment with a large single fraction of radiation., Radiation research, UNITED STATES, vol. 149 no. 4 (April, 1998), pp. 350-9, ISSN 0033-7587
   (last updated on 2004/03/30)

   Abstract:
   To test whether single high doses of radiation, similar to those used with radiosurgery, given to normal cerebral vasculature can cause changes in leukocyte-vessel wall interactions and tissue perfusion, a rat pial window model was used to view the cerebral vasculature, facilitating repeated in vivo observations of microcirculatory function. An attachment for a 4 MV linear accelerator was designed to deliver a well-collimated 2.2-mm beam of radiation to a selected region of rat brain. Sequential measurements of leukocyte-endothelial cell interactions, relative change in blood flow with laser Doppler flowmetry and vessel length density were performed prior to and at 24 h and 3 weeks after treatment with 15, 22.5 or 30 Gy, given in a single fraction. Significant increases in leukocyte-endothelial cell interactions were seen 24 h and 3 weeks after irradiation that were dependent on dose, particularly in arteries. Changes were apparent in both arteries and veins at 24 h, but by 3 weeks the effects in arteries predominated. Decreases in vessel length density and blood flow were observed and became greater with time after treatment. A variety of morphological changes were observed in irradiated arteries, including formation of aneurysmal structures, endothelial denudation and thrombus formation. These results suggest that: (1) An increase in leukocyte-vessel wall interactions occurs after irradiation; (2) cerebral arterioles are more sensitive than veins to radiation administered in this fashion; and (3) the increase in leukocyte-vessel wall interactions likely contributes to reduction of or loss of arteriolar flow, with resultant loss of flow to dependent microvascular vessels.

   Keywords:
   Animals • Arteritis • Brain • Cell Adhesion • Cerebrovascular Circulation • Dose-Response Relationship, Radiation • Endothelium, Vascular • Leukocytes • Radiation Injuries, Experimental • Rats • Rats, Sprague-Dawley • Time Factors • blood supply • cytology • etiology • pathology • radiation effects*