No abstract

. Terjung. Time course of changes in collateral blood flow and isolated vessel size and gene expression after femoral artery occlusion in rats.

Pathologic complete remission after neoadjuvant chemotherapy has a role in guiding the management of breast cancer. The present meta-analysis examined the accuracy of contrast-enhanced magnetic resonance imaging (CE-MRI) and diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting the response to neoadjuvant chemotherapy and compared CE-MRI with ultrasonography, mammography, and positron emission tomography/computed tomography (PET/CT). Medical subject heading terms and related keywords were searched to generate a compilation of eligible studies. The pooled sensitivity, specificity, diagnostic odds ratio, area under summary receiver operating characteristic curve (AUC), and Youden index (Q* index) were used to estimate the diagnostic efficacy of CE-MRI, DW-MRI, ultrasonography, mammography, and PET/CT. A total of 54 studies of CE-MRI and 8 studies of DW-MRI were included. The overall AUC and the Q* index values for CE-MRI and DW-MRI were 0.88 and 0.94 and 0.80 and 0.85, respectively. According to the summary receiver operating characteristic curves, CE-MRI resulted in a higher AUC value and Q* index compared with ultrasonography and mammography but had values similar to those of DW-MRI and PET/CT. CE-MRI accurately assessed pathologic complete remission in specificity, and PET/CT and DW-MRI accurately assessed pathologic complete remission in sensitivity. The present meta-analysis indicates that CE-MRI has high specificity and DW-MRI has high sensitivity in predicting pathologic complete remission after neoadjuvant chemotherapy. CE-MRI is more accurate than ultrasonography or mammography. Additionally, PET/CT is valuable for predicting pathologic complete remission. CE-MRI, combined with PET/CT or DW-MRI, might allow for a more precise assessment of pathologic complete remission.

We previously reported that prior training improves collateral blood flow (BF) to the calf muscles after acute-onset occlusion of the femoral artery (Yang HT et al. Am J Physiol Heart Circ Physiol 279: H1890-H1897, 2000). The purpose of this study was to test the hypothesis that increased release of nitric oxide (NO) by NO synthase (likely endothelial NOS) contributes to the increased BF to calf muscles of trained rats after acute femoral artery occlusion. Adult male Sprague-Dawley rats (~325 g) were limited to cage activity and were sedentary (SED; n = 28) or exercise trained (TR; n = 30) for 6 wk by treadmill running. On the day of the investigation, rats were anesthetized with ketamine-acepromazine and instrumented for determination of BF (using (141)Ce- and (85)Sr-labeled microspheres) and distal limb arterial pressure, and femoral arteries were occluded bilaterally. Four hours after surgery, collateral BF was determined twice during treadmill running: first at a demanding speed (20 m/min, 15% grade) and second, after a brief rest and at a faster running speed (25 m/min, 15% grade). The fact that BF did not increase further at the higher running speed indicated that maximal collateral BF was measured. Approximately half of the rats in each group received 20 mg/kg body wt N(G)-nitro-L-arginine methyl ester (L-NAME) intra-arterially 30 min before treadmill exercise and BF measurement to block production of NO by NOS. Results indicate that prior training improved collateral-dependent BF to the skeletal muscle of rats after acute femoral artery occlusion due primarily to an increase in the conductance of the upstream collateral circuit. Blockade of NOS with L-NAME produced decreased vascular conductance, both in the upstream collateral circuit and in the distal skeletal muscle microcirculation, and the difference between collateral vascular conductance in TR and SED rats was abolished. Our results indicate that the primary determinant of the increased collateral BF with prior training is the resistance of the upstream collateral circuit and imply that enhanced endothelium-mediated dilation induced by training serves to increase collateral BF following acute arterial occlusion.