Increased expression of VEGF and CD31 in postradiation rectal tissue: implications for radiation proctitis.

Background. Inflammation mediators related to radiation proctitis are partially elucidated, and neovascularization is thought to play a key role. Objectives. To investigate the expression of vascular endothelial growth factor (VEGF) and CD31 as angiogenetic markers in postradiation rectal tissue. Methods. Rectal mucosa biopsies from 11 patients who underwent irradiation for prostate cancer were examined immunohistochemically for the expression of VEGF and CD31 at three time settings-before, at the completion of, and 6 months after radiotherapy. VEGF expressing vascular endothelial cells and CD31 expressing microvessels were counted separately in 10 high-power fields (HPFs). VEGF vascular index (VEGF-VI) and microvascular density (MVD) were calculated as the mean number of VEGF positive cells per vessel or the mean number of vessels per HPF, respectively. Histological features were also evaluated. Results. VEGF-VI was significantly higher at the completion of radiotherapy (0.17 ± 0.15 versus 0.41 ± 0.24, P = 0.001) declining 6 months after. MVD increased significantly only 6 months after radiotherapy (7.3 ± 3.2 versus 10.5 ± 3.1, P < 0.005). The histopathological examination revealed inflammatory changes at the completion of radiotherapy regressing in the majority of cases 6 months after. Conclusions. Our results showed that in postradiation rectal biopsy specimens neoangiogenesis seems to be inflammation-related and constitutes a significant postradiation component of the tissue injury.

Does purgative preparation influence the diagnostic yield of small bowel video capsule endoscopy?: A meta-analysis.

OBJECTIVES: Video capsule endoscopy (VCE) is a useful tool in investigating small bowel pathology. However, the role of bowel preparation is controversial. Therefore, the aim of this study was to explore the role of bowel preparation and in particular its consequences on diagnostic yield in a meta-analysis of all relevant studies. METHODS: Extensive English-language medical literature searches were performed up to February 2008, using suitable keywords, looking for human studies that compared different modes of small bowel preparation (purgative vs. clear liquids diet). We examined the effects of this preparation on the following three primary end points, diagnostic yield (DY), small bowel visualization quality (SBVQ), and VCE completion rate (CR) by meta-analysis of relevant studies. RESULTS: A total of 12 eligible studies (6 prospective, 6 retrospective) were identified, including 16 sets of data relevant to our primary end points. There were significant differences between patients prepared with purgative vs. those prepared with clear liquids diet in DY (263 vs. 213 patients, respectively; OR (95% CI)=1.813 (1.251-2.628), P=0.002) and SBVQ (404 vs. 249 patients, respectively; OR (95% CI)=2.113 (1.252-3.566), P=0.005). There was no statistically significant difference regarding CR rate. Purgatives did not affect VCE gastric transit time (GTT) or VCE small bowel transit time (SBTT). CONCLUSIONS: Pooled data showed that in comparison to clear liquids diet, purgative bowel cleansing, before VCE, improves the SBVQ and increases the DY of the examination, but does not affect the VCE completion rate.