Citations

Abstract The Sleeping Beauty (SB) transposon system has been used as an insertional mutagenesis tool to identify novel cancer genes. To identify glioma-associated genes, we evaluated tumor formation in the brain tissue from 117 transgenic mice that had undergone constitutive SB-mediated transposition. Upon analysis, 21 samples (18%) contained neoplastic tissue with features of high-grade astrocytomas. These tumors expressed glial markers and were histologically similar to human glioma. Genomic DNA from SB-induced astrocytoma tissue was extracted and transposon insertion sites were identified. Insertions in the growth factor gene Csf1 were found in 13 of the 21 tumors (62%), clustered in introns 5 and 8. Using reverse transcription-PCR, we documented increased Csf1 RNAs in tumor versus adjacent normal tissue, with the identification of transposon-terminated Csf1 mRNAs in astrocytomas with SB insertions in intron 8. Analysis of human glioblastomas revealed increased levels of Csf1 RNA and protein. Together, these results indicate that SB-insertional mutagenesis can identify high-grade astrocytoma-associated genes and they imply an important role for CSF1 in the development of these tumors. Cancer Res; 70(9); 3557–65. ©2010 AACR.

Background There are sparse data available regarding outcome of meniscal repair performed at the time of ACL reconstruction in the pediatric and adolescent population. Purpose To review the results of meniscal repair performed at the time of ACL reconstruction in pediatric and adolescent patients. Study Design Case series; Level of evidence, 4. Methods The records of all patients age 18 years or younger who underwent meniscal repair at the time of ACL reconstruction between 1990 and 2005 were reviewed. Ninety-nine patients (56 female, 43 male) with an average age of 16 years (range, 13-18) were included. Average injury to surgery interval was 107 days (range, 2-1109). Clinical outcomes were assessed at a mean of 8 years postoperatively (range, 2-19). A multivariate model was used to compare this cohort with a previously published cohort of patients with isolated meniscal tears. Results The clinical success rate of meniscal repair was 84% for simple tears, 59% for displaced bucket-handle tears, and 57% for complex tears (74% overall). Twenty-six menisci (26% overall) failed repair and 25 patients underwent repeat arthroscopic surgery (19 partial meniscectomies, 6 re-repairs). The average Tegner and International Knee Documentation Committee scores were 6.2 (range, 2-10) and 90.3 (range, 52-100), respectively. Risk factors for failure included complex and bucket-handle tear (P = .01), medial meniscal tears (P = .03), and skeletal immaturity (P = .01). Compared with isolated meniscal repairs in a similar pediatric and adolescent population, complex tears repaired in combination with ACL reconstruction did significantly better (57% vs 13%; P = .004). Conclusion Clinically successful repair of meniscal tears treated at the time of ACL reconstruction in patients 18 years or younger depends on tear type, with complex and bucket-handle tears being negative prognostic factors. Complex tears have a higher rate of clinical success when repaired at the time of ACL reconstruction versus when repaired in isolation.

AbstractBackgroundMany researchers have previously explored the correlation between surgical flow disruptions and adverse events in cardiac surgery; however, there is no reliable tool to prospectively categorize surgical flow disruptions and the conditions that predispose a surgical team to adverse events.MethodsTwo independent raters of different medical and human factors expertise observed 12 cardiovascular operations and iteratively designed a surgical flow disruption tool (SFDT) to characterize surgical flow disruptions and the latent factors that contribute to adverse events. Categories to characterize surgical flow disruptions were created based on human factors models of human error. After the design period, both raters observed ten surgical cases using the tool to assess validity and inter‐rater reliability.ResultsRating agreement (weighted kappa) for each category across the ten surgeries was moderate to very high, resulting in strong inter‐rater reliability for each category on the surgical flow disruption tool. Use of the SFDT was simple and clear for observers of diverse backgrounds, including human factors experts and medical personnel.ConclusionsThis research depicts the development and utility of a tool to analyze surgical flow disruptions in the cardiovascular operating room with satisfactory inter‐rater reliability. This tool is an important first step in systematically categorizing and measuring surgical flow disruptions and their impact on patient safety in the operating room.

Abstract The Sleeping Beauty (SB) transposon system has been used as a somatic mutagen to identify candidate cancer genes. In previous studies, efficient leukemia/lymphoma formation on an otherwise wild-type genetic background occurred in mice undergoing whole-body mobilization of transposons, but was accompanied by high levels of embryonic lethality. To explore the utility of SB for large-scale cancer gene discovery projects, we have generated mice that carry combinations of different transposon and transposase transgenes. We have identified a transposon/transposase combination that promotes highly penetrant leukemia/lymphoma formation on an otherwise wild-type genetic background, yet does not cause embryonic lethality. Infiltrating gliomas also occurred at lower penetrance in these mice. SB-induced or accelerated tumors do not harbor large numbers of chromosomal amplifications or deletions, indicating that transposon mobilization likely promotes tumor formation by insertional mutagenesis of cancer genes, and not by promoting wide-scale genomic instability. Cloning of transposon insertions from lymphomas/leukemias identified common insertion sites at known and candidate novel cancer genes. These data indicate that a high mutagenesis rate can be achieved using SB without high levels of embryonic lethality or genomic instability. Furthermore, the SB system could be used to identify new genes involved in lymphomagenesis/leukemogenesis. [Cancer Res 2009;69(21):8429–37]

Fifteen percent of lung cancer cases occur in never-smokers and show characteristics that are molecularly and clinically distinct from those in smokers. Epidermal growth factor receptor ( EGFR ) gene mutations, which are correlated with sensitivity to EGFR-tyrosine kinase inhibitors (EGFR-TKIs), are more frequent in never-smoker lung cancers. In this study, microRNA (miRNA) expression profiling of 28 cases of never-smoker lung cancer identified aberrantly expressed miRNAs, which were much fewer than in lung cancers of smokers and included miRNAs previously identified (e.g., up-regulated miR-21) and unidentified (e.g., down-regulated miR-138) in those smoker cases. The changes in expression of some of these miRNAs, including miR-21, were more remarkable in cases with EGFR mutations than in those without these mutations. A significant correlation between phosphorylated-EGFR ( p -EGFR) and miR-21 levels in lung carcinoma cell lines and the suppression of miR-21 by an EGFR-TKI, AG1478, suggest that the EGFR signaling is a pathway positively regulating miR-21 expression. In the never-smoker–derived lung adenocarcinoma cell line H3255 with mutant EGFR and high levels of p -EGFR and miR-21, antisense inhibition of miR-21 enhanced AG1478-induced apoptosis. In a never-smoker–derived adenocarcinoma cell line H441 with wild-type EGFR , the antisense miR-21 not only showed the additive effect with AG1478 but also induced apoptosis by itself. These results suggest that aberrantly increased expression of miR-21, which is enhanced further by the activated EGFR signaling pathway, plays a significant role in lung carcinogenesis in never-smokers, as well as in smokers, and is a potential therapeutic target in both EGFR -mutant and wild-type cases.

Object A review of the literature has revealed scant data related to neurosurgical treatment of gravid patients. The authors reviewed their experience with the neurosurgical treatment of pregnant women to better characterize the optimal management strategies for intracranial pathological entities in this population. Methods Between July 1969 and July 2005, 34 patients with documented pregnancy and concomitant intracranial pathological entities were treated at the authors' institution. The average age of the gravid patients at presentation was 27 ± 6 years. Twelve patients harbored vascular and 14 patients harbored neoplastic lesions. Four gravid patients suffered from traumatic intracranial hemorrhage, 2 had primary intracerebral hemorrhage, and 2 had hydrocephalus. The medical records of these patients were reviewed to assess the outcome for the mothers and fetuses. Results Nineteen pregnant patients (56%) underwent a neurosurgical procedure after induction of general anesthesia. Of these, 14 (74%) underwent craniotomies for clipping/resection of their lesion, 2 (10%) underwent stereotactic biopsies, and 3 (16%) underwent CSF shunting procedures. Three patients (9%) delivered by cesarean section followed by their neurosurgical procedure, and 5 (15%) underwent therapeutic abortion preoperatively to allow for radiation therapy early in their pregnancy (4 of these patients underwent surgery prior to their therapeutic abortion). Eleven patients (32%) were treated nonoperatively while pregnant, and 3 of these received their treatment after delivery. There was no operative maternal mortality or permanent morbidity. The fetuses did not suffer from any complications related to the mother's neurosurgical procedure. Conclusions Based on the authors' experience and a review of the literature, surgery for intracranial lesions in pregnant patients is generally well tolerated by both mother and fetus. Preoperative delivery by cesarean section of term or near-term babies is reasonable. Some patients treated conservatively may deteriorate and require an operation.

AbstractAs multiple myeloma tumors universally dysregulate cyclin D genes we conducted high-throughput chemical library screens for compounds that induce suppression of cyclin D2 promoter transcription. The top-ranked compound was a natural triterpenoid, pristimerin. Strikingly, the early transcriptional response of cells treated with pristimerin closely resembles cellular responses elicited by proteosome inhibitors, with rapid induction of heat shock proteins, activating transcription factor 3 (ATF3), and CHOP. Enzymatic assays and immunoblotting confirm that pristimerin rapidly (< 90 minutes) and specifically inhibits chymotrypsin-like proteosome activity at low concentrations (< 100 nM) and causes accumulation of cellular ubiquitinated proteins. Notably, cytotoxic triterpenoids including pristimerin inhibit NF-κB activation via inhibition of IKKα or IKKβ, whereas proteosome inhibitors instead suppress NF-κB function by impairing degradation of ubiquitinated IκB. By inhibiting both IKK and the proteosome, pristimerin causes overt suppression of constitutive NF-κB activity in myeloma cells that may mediate its suppression of cyclin D. Multiple myeloma is exquisitely sensitive to proteosome or NF-κB pathway inhibition. Consistent with this, pristimerin is potently and selectively lethal to primary myeloma cells (IC50 < 100 nM), inhibits xenografted plasmacytoma tumors in mice, and is synergistically cytotoxic with bortezomib—providing the rationale for pharmaceutical development of triterpenoid dual-function proteosome/NF-κB inhibitors as therapeutics for human multiple myeloma and related malignancies.

AbstractUnderstanding patterns of etiologic commonality and heterogeneity for non-Hodgkin lymphomas may illuminate lymphomagenesis. We present the first systematic comparison of risks by lymphoma subtype for a broad range of putative risk factors in a population-based case-control study, including diffuse large B-cell (DLBCL; N = 416), follicular (N = 318), and marginal zone lymphomas (N = 106), and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL; N = 133). We required at least 2 of 3 analyses to support differences in risk: (1) polytomous logistic regression, (2) homogeneity tests, or (3) dichotomous logistic regression, analyzing all 7 possible pairwise comparisons among the subtypes, corresponding to various groupings by clinical behavior, genetic features, and differentiation. Late birth order and high body mass index (≥ 35) kg/m2) increased risk for DLBCL alone. Autoimmune conditions increased risk for marginal zone lymphoma alone. The tumor necrosis factor G-308A polymorphism (rs1800629) increased risks for both DLBCL and marginal zone lymphoma. Exposure to certain dietary heterocyclic amines from meat consumption increased risk for CLL/SLL alone. We observed no significant risk factors for follicular lymphoma alone. These data clearly support both etiologic commonality and heterogeneity for lymphoma subtypes, suggesting that immune dysfunction is of greater etiologic importance for DLBCL and marginal zone lymphoma than for CLL/SLL and follicular lymphoma.

Object Cerebral cortex electrophysiology is poorly sampled using standard, low spatial resolution clinical intracranial electrodes. Adding microelectrode arrays to the standard clinical macroelectrode arrays increases the spatial resolution and may ultimately improve the clinical utility of intracranial electroencephalography (iEEG). However, the safety of hybrid electrode systems containing standard clinical macroelectrode and microelectrode arrays is not yet known. The authors report on their preliminary experience in 24 patients who underwent implantation of hybrid electrodes. Methods In this study, 24 consecutive patients underwent long-term iEEG monitoring with implanted hybrid depth and subdural grid and strip electrodes; both clinical macroelectrodes and research microelectrodes were used. The patients included 18 women and 6 men with an average age of 35 ± 12 years (range 21–65). The mean hospital stay was 11 ± 4 days (range 5–20), with mean duration of implantation 7.0 ± 3.2 days (range 3–15). Data from the 198 consecutive craniotomies for standard clinical subdural grid insertion (prior to surgery in the 24 patients described here) were used for comparison to investigate the relative risk of complications. Results Focal seizure identification and subsequent resection was performed in 20 patients. One patient underwent a subsequent operation after neurological deterioration secondary to cerebral swelling and a 5-mm subdural hematoma. There were no infections. The overall complication rate was 4.2% (only 1 patient had a complication), which did not significantly differ from the complication rate previously reported by the authors of 6.6% when standard subdural and depth intracranial electrodes were used. There were no deaths or permanent neurological deficits related to electrode implantation. Conclusions The authors demonstrate the use of hybrid subdural strip and grid electrodes containing high-density microwire arrays and standard clinical macroelectrodes. Hybrid electrodes provide high spatial resolution electrophysiology of the neocortex that is impossible with standard clinical iEEG. In this initial study in 24 patients, the complication rate is acceptable, and there does not appear to be increased risk associated with the use of hybrid electrodes compared with standard subdural and depth iEEG electrodes. More research is required to show whether hybrid electrode recordings will improve localization of epileptic foci and tracking the generation of neocortical seizures.