Faculty Bibliography

OBJECTIVE:The aim of this work was to determine the role of MRI in interpreting abnormal signals within bones and soft tissues adjacent to tumor bulk of osteosarcoma and Ewing's sarcoma in a pediatric population by correlating MR findings with histopathology. MATERIALS AND METHODS/METHODS:Thirty patients met the inclusion criteria, which included (1) osteosarcoma or Ewing's sarcoma, (2) MR studies no more than 2 months prior to surgery, (3) presence of abnormal MR signal surrounding the tumor bulk, (4) pathological material from resected tumor. The patients received standard neoadjuvant chemotherapy. Using grid maps on gross pathology specimens, the abnormal MR areas around the tumor were matched with the corresponding grid sections. Histopathology slides of these sections were then analyzed to determine the nature of the regions of interest. The MR/pathological correlation was evaluated using Mann-Whitney U test and Fisher's exact test. RESULTS:Twenty-seven patients had osteosarcoma and three patients had Ewing's sarcoma. Of the studied areas, 17.4% were positive for tumor (viable or necrotic). There was no statistically significant correlation between areas positive for tumor and age, gender, signal extent and intensity on MRI, or tissue type. There was, however, a statistically significant correlation between presence of tumor and the appearance of abnormal soft tissue signals. A feathery appearance correlated with tumor-negative areas whereas a bulky appearance correlated with tumor-positive regions. CONCLUSIONS:MR imaging is helpful in identifying the nature of abnormal signal areas surrounding bone sarcomas that are more likely to be tumor-free, particularly when the signal in the soft tissues surrounding the tumor is feathery and edema-like in appearance.

OBJECTIVE:To assess the effect of sildenafil citrate in a rat model of Nω-nitro-l-arginine methyl ester (L-NAME)-induced intrauterine growth restriction (IUGR). STUDY DESIGN/METHODS:An in vivo experimental study was conducted where 40 pregnant Sprague-Dawley rats were randomly assigned to receive either: (1) control, (2) L-NAME 50 mg/kg/d by gavage (days 14 to 19), (3) L-NAME and sildenafil 15 mg/kg/d by gavage, or (4) sildenafil (days 14 to 21). On day 21, a hysterotomy was performed and all fetuses (live and dead) were counted, examined, and weighed. The primary outcome measure was the difference in pup birth weight. RESULTS:The median number of live pups per dam was 11.5 (range: 1 to 15), 13.5 (2 to 17), 13.5 (7 to 16), and 11.5 (4 to 17) in controls, L-NAME, sildenafil, and combined drug groups, respectively (p = 0.02). Rats treated with L-NAME had a significantly higher number of stillbirths compared with control (p = 0.013) and sildenafil (p = 0.008) groups. L-NAME reduced pup birth weight compared with controls (4.53 ± 1.49 versus 5.65 ± 1.63 g, p < 0.001); this effect was more pronounced in the L-NAME and sildenafil groups (3.37 ± 1.25 g, p < 0.001). CONCLUSION/CONCLUSIONS:Our data indicate that sildenafil citrate does not ameliorate L-NAME-induced IUGR, and in the doses utilized in this study might even have a synergistic negative effect on pup birth weight.