Faculty Bibliography

OBJECTIVE:Optical contrast agents for brain tumor delineation have been previously evaluated in ex vivo specimens from animals with implanted gliomas and may not reflect the true visual parameters encountered during surgery. This study describes a novel model system designed to evaluate optical contrast agents for tumor delineation in vivo. METHODS:Biparietal craniectomies were performed on 8-week-old Sprague-Dawley rats. 9L glioma cells were injected intraparenchymally. A cover slip was bonded to the cranial defect with cyanoacrylate glue. When the tumor radius reached 1 mm, Coomassie Blue was administered intravenously while the appearance of the cortical surface was recorded. Computerized image analysis of the red/green/blue color components was used to quantify visible differences between tumor and nonneoplastic tissue and to compare delineation in the brain tumor window (BTW) model with the conventional 9L glioma model. RESULTS:The tumor margin in the BTW model was poorly defined before contrast administration but readily apparent after contrast administration. Based on red component intensity, tumor delineation improved 4-fold at 50 minutes after contrast administration in the BTW model (P < .002). The conventional 9L glioma model overestimated the degree of delineation compared with the BTW model at the same dose of Coomassie Blue (P < .03). CONCLUSION/CONCLUSIONS:Window placement overlying an implanted glioma is technically possible and well tolerated in the rat. The BTW model is a valid system for evaluating optical contrast agents designed to delineate brain tumor margins. To our knowledge, we have described the first in vivo model system for evaluating optical contrast agents for tumor delineation.

BACKGROUND:Anterior cervical hyperosteophytosis describes the excessive formation of osteophytes along the ventral spine. Dysphagia due to ACH is considered an uncommon entity described mainly in case reports. Symptomatic ACH has been attributed to multiple etiologies including DISH, trauma, postlaminectomy syndromes, and cervical spondylosis. We report one of the largest series of patients with ACH-induced dysphagia requiring surgery. METHODS:After IRB approval, a retrospective chart review was completed. From 2001 to 2006, 9 patients presented with dysphagia due to ACH requiring surgical treatment. RESULTS:Eight patients were male, and the mean age was 65.1 years. Cervical spine x-rays and CT clearly demonstrated ACH in each case. Esophagram or a video fluoroscopic swallowing study was used to verify that dysphagia was caused by osteophytic overgrowth in all instances but one. In 2 patients, a focal osteophyte had formed adjacent to a previously fused segment. Of the remaining 7 patients, osteophytic formation was attributed to cervical spondylosis in 2 patients and DISH in 5 patients. All patients underwent osteophytectomy without spinal fusion. Average follow-up was 9.8 months. Although all 9 patients experienced resolution of dysphagia, improvement was delayed in 2 patients. CONCLUSIONS:Diffuse idiopathic skeletal hyperostosis and spondylosis are the most common etiologies accounting for ACH-induced dysphagia. Adjacent segment disease may also be a potential cause of symptomatic ACH and has not been previously reported. Regardless of etiology, surgical resection is highly successful if conservative measures fail.

OBJECTIVE:To synthesize and complete in vitro characterization of a novel, tumor-targeted nanodevice for visible intraoperative delineation of brain tumors. METHODS:The ability of dye-loaded polyacrylamide nanoparticles (NP) containing methylene blue, Coomassie blue, or indocyanine green to cause color change in the 9L glioma cell lines was evaluated. Cells were incubated with dye-loaded NPs, photographed, and analyzed colorimetrically. Confocal microscopy was used to determine subcellular localization of NPs in treated cells. RESULTS:Incubation of glioma cell lines with dye-loaded NPs resulted in clearly visible, quantifiable cell tagging in a dose- and time-dependent manner. Dye-loaded NPs were observed to bind to the surface and become internalized by glioma cells. Coating the NP surface with F3, a peptide that binds to the tumor cell surface receptor nucleolin, significantly increased NP affinity for glioma cells. F3 targeting also significantly increased the rate of cell tagging by dye-loaded NPs. Finally, F3-targeted NPs demonstrated specificity for targeting various cancer cell lines based on their surface expression of cell surface nucleolin. CONCLUSION/CONCLUSIONS:F3-targeted dye-loaded NPs efficiently cause definitive color change in glioma cells. This report represents the first use of targeted NPs to cause a visible color change in tumor cell lines. Similar nanodevices may be used in the future to enable visible intraoperative tumor delineation during tumor resection.

E2F-mediated control of gene expression is believed to have an essential role in the control of cellular proliferation. Using a conditional gene-targeting approach, we show that the targeted disruption of the entire E2F activator subclass composed of E2f1, E2f2, and E2f3 in mouse embryonic fibroblasts leads to the activation of p53 and the induction of p53 target genes, including p21(CIP1). Consequently, cyclin-dependent kinase activity and retinoblastoma (Rb) phosphorylation are dramatically inhibited, leading to Rb/E2F-mediated repression of E2F target gene expression and a severe block in cellular proliferation. Inactivation of p53 in E2f1-, E2f2-, and E2f3-deficient cells, either by spontaneous mutation or by conditional gene ablation, prevented the induction of p21(CIP1) and many other p53 target genes. As a result, cyclin-dependent kinase activity, Rb phosphorylation, and E2F target gene expression were restored to nearly normal levels, rendering cells responsive to normal growth signals. These findings suggest that a critical function of the E2F1, E2F2, and E2F3 activators is in the control of a p53-dependent axis that indirectly regulates E2F-mediated transcriptional repression and cellular proliferation.

The effect of in vivo and in vitro thymulin treatments on macrophage responsiveness to interferon-gamma was evaluated in chickens. Seven-week-old chickens were treated with 0, 1, 10, or 100ng thymulin per 100g body weight. Abdominal exudate cells (AEC), a source of macrophages, were harvested and cultured in the presence of graded levels of recombinant chicken interferon-gamma (ChIFN-gamma). Responsiveness to ChIFN-gamma was determined by measuring the induction of nitric oxide production. One and 2-day thymulin treatment at 10 and 100ng per 100g body weight doses significantly increased responsiveness to ChIFN-gamma while 1ng per 100g body weight had no effect. Other experiments compared the effect of thymulin treatments in Cornell K strain chickens, having normal serum thymulin levels with sex-linked dwarf (SLD) chickens which are deficient in serum thymulin. The dose of thymulin treatment required to significantly increase responsiveness to ChIFN-gamma differed between strains. Finally, the effect of direct in vitro thymulin treatments on macrophage responsiveness to ChIFN-gamma was evaluated. There were no significant increases in responsiveness to ChIFN-gamma between treatment groups within the macrophage cell line, HD-11, when cultured in the presence of 0-200pg thymulin/ml. These data suggest that the effect of thymulin on AEC responsiveness to ChIFN-gamma is indirectly mediated.