Brain AVM surgery without endovascular embolization in a low to middle income country

We treated a 20-year-old woman in Paraguay with a ruptured intraventricular Spetzler-Martin Grade 3 AVM, and illustrate microsurgical resection without embolization in this video.

Combination endovascular and microsurgical treatment of partially thrombosed ruptured ICA terminus aneurysm, with common carotid artery to MCA bypass via saphenous vein graft and parent vessel sacrifice after coil embolization

A 63-year-old woman presented with ruptured giant ICA terminus aneurysm, temporized with coil embolization and definitively treated with parent vessel sacrifice and high-flow bypass.

Operative Technique and Complication Management in a Case of Giant Esthesioneuroblastoma Resected by a Combined Transcranial and Endonasal Endoscopic Approach: Technical Case Report

BACKGROUND AND IMPORTANCE

Esthesioneuroblastoma (ENB) is a rare anterior skull base tumor derived from olfactory epithelium. There are very few operative videos in the literature demonstrating the surgical resection techniques for giant ENB because of their rarity and complexity. In this technical report, we demonstrate the microsurgical resection of a very large and complex high-grade ENB, initially deemed unresectable, through a bifrontal craniotomy and extended subfrontal approach combined with an endonasal endoscopic approach.

CLINICAL PRESENTATION

A 34-year-old woman presented with headaches, nasal congestion, and bloody nasal drainage. MRI showed a large nasal cavity mass with extension into the anterior cranial fossa and bifrontal lobes. There was significant bifrontal edema causing headaches and abutting the optic nerves. Initial management with surgical resection was offered to the patient for local tumor control and to preserve her vision. A combined bifrontal craniotomy and endonasal transsphenoidal approach was used for resecting this giant tumor. After achieving gross total resection, we reconstructed the anterior skull base in layers. She developed several postoperative complications which were appropriately managed.

CONCLUSION

We demonstrate the surgical resection of a giant ENB through a combined transcranial and endonasal endoscopic approach. We discuss the several postoperative complications in this complex case and the lessons learned.

Three Column Cervical Fracture-Dislocation in a 3-Year-Old Boy

Complete traumatic cervical fracture-dislocation with spinal cord transection in children is a rare entity with no evidence-based guidelines on management. The authors reviewed the literature for pediatric spinal cord injury and present the case of a 3-year-old with traumatic cervical fracture-dislocation and spinal cord transection who presented as a cervical-6 complete spinal cord injury (ASIA A). His other organ systems injured included liver, spleen, bowel, and abdominal aortic injury. The patient underwent halo placement for preoperative reduction followed by open reduction and internal fixation with posterior segmental instrumented fusion. Intraoperatively, the patient had motor evoked potential signals present below the level of his injury. Early postoperative follow-up demonstrated that, although his leg function did not improve, he did demonstrate improvement in upper extremities. This is a rare case of complete cervical spinal cord transection in a pediatric patient. We elected to manage this challenging case with initial external reduction and orthosis with a halo vest followed by acute posterior cervical fusion. Despite a cervical-6 injury level on clinical exam, there was electrographic evidence of function below that level on intraoperative neuromonitoring. Postoperatively the patient has recovered some lost function.

EPCO-23. A SINGLE-CELL BASED PRECISION MEDICINE APPROACH USING GLIOBLASTOMA PATIENT-SPECIFIC MODELS

Glioblastoma is a heterogeneous tumor made up of cell states that evolve over time. We modeled tumor evolutionary trajectories during standard-of-care treatment using multimodal single-cell analysis of a primary tumor sample, corresponding mouse xenografts subjected to standard of care therapy, and recurrent tumor at autopsy. We mined the multimodal data with single cell SYstems Genetics Network AnaLysis (scSYGNAL) to identify a network of 52 regulators that mediate treatment-induced shifts in xenograft tumor-cell states that were also reflected in recurrence. By integrating scSYGNAL-derived regulatory network information with transcription factor accessibility deviations derived from single-cell ATAC-seq data, we developed consensus networks that regulate subpopulations of primary and recurrent tumor cells. Finally, by matching targeted therapies to active regulatory networks underlying tumor evolutionary trajectories, we provide a framework for applying single-cell-based precision medicine approaches in a concurrent, neo-adjuvant, or recurrent setting. Our proof-of-concept work herein provides the basis for the development of a modeling and analytical system that enables single-cell characterization of an individual patient’s tumor and inferred therapeutic vulnerabilities. Although further validation is required, in the form of in vivo studies of these putative druggable targets, our preliminary analysis and results suggest that systems biology techniques can be used to infer and predict therapeutic vulnerabilities that are either selected or induced during standard-of-care treatment. Ultimately, the information gathered from such systematic modeling and analysis of individual tumors may inform clinical treatment in a more targeted manner and enable a rational, tailored precision medicine that accounts for intratumoral cell heterogeneity.

Prognostic Value of Hemorrhagic Brainstem Injury on Early Computed Tomography: A TRACK-TBI Study

BACKGROUND

Traumatic brainstem injury has yet to be incorporated into widely used imaging classification systems for traumatic brain injury (TBI), and questions remain regarding prognostic implications for this TBI subgroup. To address this, retrospective data on patients from the multicenter prospective Transforming Research and Clinical Knowledge in TBI study were studied.

METHODS

Patients with brainstem and cerebrum injury (BSI+) were matched by age, sex, and admission Glasgow Coma Scale (GCS) score to patients with cerebrum injuries only. All patients had an interpretable head computed tomography (CT) scan from the first 48 hours after injury and a 6-month Glasgow Outcome Scale Extended (GOSE) score. CT scans were reviewed for brainstem lesions and, when present, characterized by location, size, and type (traumatic axonal injury, contusion, or Duret hemorrhage). Clinical, demographic, and outcome data were then compared between the two groups.

RESULTS

Mann-Whitney U-tests showed no significant difference in 6-month GOSE scores in patients with BSI+ (mean 2.7) compared with patients with similar but only cerebrum injuries (mean 3.9), although there is a trend (p = 0.10). However, subclassification by brainstem lesion type, traumatic axonal injury (mean 4.0) versus Duret hemorrhage or contusion (mean 1.4), did identify a proportion of BSI+ with significantly less favorable outcome (p = 0.002). The incorporation of brainstem lesion type (traumatic axonal injury vs. contusion/Duret), along with GCS into a multivariate logistic regression model of favorable outcome (GOSE score 4-8) did show a significant contribution to the prognostication of this brainstem injury subgroup (odds ratio 0.08, 95% confidence interval 0.00-0.67, p = 0.01).

CONCLUSIONS

These findings suggest two groups of patients with brainstem injuries may exist with divergent recovery potential after TBI. These data support the notion that newer CT imaging classification systems may augment traditional clinical measures, such as GCS in identifying those patients with TBI and brainstem injuries that stand a higher chance of favorable outcome.

A Systems Approach to Brain Tumor Treatment

Brain tumors are among the most lethal tumors. Glioblastoma, the most frequent primary brain tumor in adults, has a median survival time of approximately 15 months after diagnosis or a five-year survival rate of 10%; the recurrence rate is nearly 90%. Unfortunately, this prognosis has not improved for several decades. The lack of progress in the treatment of brain tumors has been attributed to their high rate of primary therapy resistance. Challenges such as pronounced inter-patient variability, intratumoral heterogeneity, and drug delivery across the blood-brain barrier hinder progress. A comprehensive, multiscale understanding of the disease, from the molecular to the whole tumor level, is needed to address the intratumor heterogeneity resulting from the coexistence of a diversity of neoplastic and non-neoplastic cell types in the tumor tissue. By contrast, inter-patient variability must be addressed by subtyping brain tumors to stratify patients and identify the best-matched drug(s) and therapies for a particular patient or cohort of patients. Accomplishing these diverse tasks will require a new framework, one involving a systems perspective in assessing the immense complexity of brain tumors. This would in turn entail a shift in how clinical medicine interfaces with the rapidly advancing high-throughput (HTP) technologies that have enabled the omics-scale profiling of molecular features of brain tumors from the single-cell to the tissue level. However, several gaps must be closed before such a framework can fulfill the promise of precision and personalized medicine for brain tumors. Ultimately, the goal is to integrate seamlessly multiscale systems analyses of patient tumors and clinical medicine. Accomplishing this goal would facilitate the rational design of therapeutic strategies matched to the characteristics of patients and their tumors. Here, we discuss some of the technologies, methodologies, and computational tools that will facilitate the realization of this vision to practice.

Radiogenomic modeling predicts survival-associated prognostic groups in glioblastoma

Background

Combined whole-exome sequencing (WES) and somatic copy number alteration (SCNA) information can separate isocitrate dehydrogenase (IDH)1/2-wildtype glioblastoma into two prognostic molecular subtypes, which cannot be distinguished by epigenetic or clinical features. The potential for radiographic features to discriminate between these molecular subtypes has yet to be established.

Methods

Radiologic features (n = 35 340) were extracted from 46 multisequence, pre-operative magnetic resonance imaging (MRI) scans of IDH1/2-wildtype glioblastoma patients from The Cancer Imaging Archive (TCIA), all of whom have corresponding WES/SCNA data. We developed a novel feature selection method that leverages the structure of extracted MRI features to mitigate the dimensionality challenge posed by the disparity between a large number of features and the limited patients in our cohort. Six traditional machine learning classifiers were trained to distinguish molecular subtypes using our feature selection method, which was compared to least absolute shrinkage and selection operator (LASSO) feature selection, recursive feature elimination, and variance thresholding.

Results

We were able to classify glioblastomas into two prognostic subgroups with a cross-validated area under the curve score of 0.80 (±0.03) using ridge logistic regression on the 15-dimensional principle component analysis (PCA) embedding of the features selected by our novel feature selection method. An interrogation of the selected features suggested that features describing contours in the T2 signal abnormality region on the T2-weighted fluid-attenuated inversion recovery (FLAIR) MRI sequence may best distinguish these two groups from one another.

Conclusions

We successfully trained a machine learning model that allows for relevant targeted feature extraction from standard MRI to accurately predict molecularly-defined risk-stratifying IDH1/2-wildtype glioblastoma patient groups.

Magnetic resonance perfusion image features uncover an angiogenic subgroup of glioblastoma patients with poor survival and better response to antiangiogenic treatment

Background

In previous clinical trials, antiangiogenic therapies such as bevacizumab did not show efficacy in patients with newly diagnosed glioblastoma (GBM). This may be a result of the heterogeneity of GBM, which has a variety of imaging-based phenotypes and gene expression patterns. In this study, we sought to identify a phenotypic subtype of GBM patients who have distinct tumor-image features and molecular activities and who may benefit from antiangiogenic therapies.

Methods

Quantitative image features characterizing subregions of tumors and the whole tumor were extracted from preoperative and pretherapy perfusion magnetic resonance (MR) images of 117 GBM patients in 2 independent cohorts. Unsupervised consensus clustering was performed to identify robust clusters of GBM in each cohort. Cox survival and gene set enrichment analyses were conducted to characterize the clinical significance and molecular pathway activities of the clusters. The differential treatment efficacy of antiangiogenic therapy between the clusters was evaluated.

Results

A subgroup of patients with elevated perfusion features was identified and was significantly associated with poor patient survival after accounting for other clinical covariates (P values <.01; hazard ratios > 3) consistently found in both cohorts. Angiogenesis and hypoxia pathways were enriched in this subgroup of patients, suggesting the potential efficacy of antiangiogenic therapy. Patients of the angiogenic subgroups pooled from both cohorts, who had chemotherapy information available, had significantly longer survival when treated with antiangiogenic therapy (log-rank P=.022).

Conclusions

Our findings suggest that an angiogenic subtype of GBM patients may benefit from antiangiogenic therapy with improved overall survival.

Increased risk for complications following diagnostic cerebral angiography in older patients: Trends from the Nationwide Inpatient Sample (1999-2009)

The full utility of diagnostic cerebral angiography, an invasive cerebrovascular imaging technique, is currently debated. Our goal was to determine trends in diagnostic cerebral angiography utilization and associated complications from 1999 through 2009. The National Inpatient Sample (NIS) was used to identify patients who received primary cerebral angiography from 1999-2009 in the United States. We observed trends in discharge volume, total mean charge, and post-procedural complications for this population. Data was based on sample projections and analyzed using univariate and multivariate regression. There were a total of 424,105 discharges indicating primary cerebral angiography nationwide from 1999-2009. The majority of these cases (65%) were in patients older than 55years. Embolic stroke was the most frequent complication, particularly in the oldest age bracket, occurring in 16,304 patients. The risk for complications increased with age (p<0.0001) and with other underlying health conditions. Pulmonary, deep vein thrombosis, and renal associated comorbidities resulted in the greatest risk for developing post-procedural complications. Throughout the study period case volume for cerebral angiography remained constant while total charge per patient increased from $17,365 in 1999 to $45,339 in 2009 (p<0.001). While the overall complication rate for this invasive procedure is relatively low, the potential risk for embolic stroke in older patients is significant. It is worth considering less invasive diagnostic techniques for an older and at risk patient population.

Computational Identification of Tumor Anatomic Location Associated with Survival in 2 Large Cohorts of Human Primary Glioblastomas

BACKGROUND AND PURPOSE

Tumor location has been shown to be a significant prognostic factor in patients with glioblastoma. The purpose of this study was to characterize glioblastoma lesions by identifying MR imaging voxel-based tumor location features that are associated with tumor molecular profiles, patient characteristics, and clinical outcomes.

MATERIALS AND METHODS

Preoperative T1 anatomic MR images of 384 patients with glioblastomas were obtained from 2 independent cohorts (n = 253 from the Stanford University Medical Center for training and n = 131 from The Cancer Genome Atlas for validation). An automated computational image-analysis pipeline was developed to determine the anatomic locations of tumor in each patient. Voxel-based differences in tumor location between good (overall survival of >17 months) and poor (overall survival of <11 months) survival groups identified in the training cohort were used to classify patients in The Cancer Genome Atlas cohort into 2 brain-location groups, for which clinical features, messenger RNA expression, and copy number changes were compared to elucidate the biologic basis of tumors located in different brain regions.

RESULTS

Tumors in the right occipitotemporal periventricular white matter were significantly associated with poor survival in both training and test cohorts (both, log-rank P < .05) and had larger tumor volume compared with tumors in other locations. Tumors in the right periatrial location were associated with hypoxia pathway enrichment and PDGFRA amplification, making them potential targets for subgroup-specific therapies.

CONCLUSIONS

Voxel-based location in glioblastoma is associated with patient outcome and may have a potential role for guiding personalized treatment.

Abstract PR12: Overcoming immune evasion in pediatric hematologic and solid tumor malignancies: A preclinical study using a humanized anti-CD47 antibody

CD47 is an anti-phagocytic cell surface protein mediating cancer cell evasion of phagocytosis by the innate immune system. Preclinical data suggest that CD47 is appears to be an indispensable means by which many cancer cells, including cancer stem cells, overcome intrinsic expression of their pro-phagocytic “eat me” signals. Blockade of CD47 with mAbs enables phagocytosis of cancer cells in vitro and in vivo. We have developed a novel humanized mAb (huCD47-Ab) that specifically binds CD47 and blocks it from interacting with its ligand, signal regulatory protein–α; (SIRPα), on phagocytic cells, resulting in the phagocytosis and elimination of cancer cells through their “eat me” signals. Normal cells generally do not express eat me signals, and are unaffected by CD47 blocking mAb. We observed expression of CD47 on aggressive pediatric tumors, including acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), Ewing's sarcoma, neuroblastoma, and several cancers of the central nervous system (CNS), including atypical tetroid rhabdoid tumor (ATRT), primitive neuroectodermal tumor (PNET), medulloblastoma (MB), and pediatric high-grade glioma (pHGG). In-vitro phagocytosis assays, of primary patient samples shows significant engulfment by human peripheral blood derived macrophages upon incubation with the HuCD47-Ab antibody as compared to control. Furthermore we observe potent anti-tumor efficacy and survival benefit in MB, pHGG, ATRT and PNET orthotopic xenografts models establishing the ability of the huCD47 antibody to across the blood brain barrier by the CD47 blocking antibody. Using a novel human neural stem cell/brain tumor co-engraftment orthotopic xenograft model we show specificity of the HuCD47 antibody to only tumor cells and not normal human cells. We further observe potent anti-tumor efficacy in non-CNS tumor (ALL, AML and Osteosarcoma) xenograft models as well.

Furthermore we demonstrate that HuCD47-Ab can be administered safely to non-human primates at therapeutic serum levels. Pre-IND and IMPD meetings with the FDA in the US and the MHRA in the UK, have been held, and the clinical trials for adult patients with advanced stage malignancies will start in early 2014. After determining safety in these phase I trials, we initiate protocols for adult CNS tumors as part of expansion cohorts, and subsequently extend the trials to pediatric cancer patients, given manageable toxicity and signs of efficacy in the adult patients.

This abstract is also presented as Poster A86.

Citation Format: Siddhartha S. Mitra, Sharareh Gholamin, Jens-Peter Volkmer, Abdullah Feroze, Jie Liu, Achal Achrol, Lijuan Wang, Leanne Sayles, Michael Zhang, Kathleen Sakamoto, Michelle Monje-Deisseroth, Yoon-Jae Cho, Alejandro Sweet-Cordero, Ravi Majeti, Samuel Cheshier, Irving Weissman. Overcoming immune evasion in pediatric hematologic and solid tumor malignancies: A preclinical study using a humanized anti-CD47 antibody. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr PR12.

Endovascular management of cerebral venous sinus thrombosis

Cerebral venous sinus thrombosis (CVST) is characterized by formation of widespread thrombus within the cerebral venous sinus system. CVST can cause venous hypertension, venous infarcts, hemorrhage and seizures. It is managed in most cases with systemic anticoagulation through the use of heparin to resolve the thrombus. Patients that demonstrate clinical deterioration while on heparin are often treated with endovascular strategies to recanalize the sinuses. We present the case of a patient with widespread CVST, involving his superior sagittal sinuses and bilateral transverse sigmoid sinuses, who was treated with a combination of endovascular therapies. The video can be found here: http://youtu.be/w3wAGlT7h8c .

Experience with intraoperative navigation and imaging during endoscopic transnasal spinal approaches to the foramen magnum and odontoid

Object

In this study the authors share their experience using intraoperative spinal navigation and imaging for endoscopic transnasal approaches to the odontoid in 5 patients undergoing C1–2 surgery for basilar invagination at Stanford Hospital and Clinics from 2010 to 2013.

Methods

Of these 5 patients undergoing C1–2 surgery for basilar invagination, 4 underwent a 2-tiered anterior C1–2 resection with posterior occipitocervical fusion during a first stage surgery, followed by endoscopic endonasal odontoidectomy in a separate setting. Intraoperative stereotactic navigation was performed using a surgical navigation system in all cases. Navigation accuracy, characterized as target registration error, ranged between 0.8 mm and 2 mm, with an average of 1.2 mm. Intraoperative imaging using a CT scanner was also performed in 2 patients.

Results

Endoscopic decompression of the brainstem was achieved in all patients, and no intraoperative complications were encountered. All patients were extubated within 24 hours after surgery and were able to swallow within 48 hours. After appropriate initial reconstruction of the defect at the craniocervical junction, no postoperative CSF leakage, arterial injury, or need for reoperation was encountered; 1 patient developed mild postoperative velopharyngeal insufficiency that resolved by the 6-month follow-up evaluation. There were no deaths and no patients required tracheostomy placement. The average inpatient stay after surgery varied between 72 and 96 hours, without extended intensive care unit stays for any patient.

Conclusions

Technologies such as intraoperative CT scanning and merged MRI/CT can provide the surgeon with detailed, virtual real-time information about the extent of complex endoscopic vertebral segment resection and brainstem decompression and lessens the prospect of revision or secondary procedures in this challenging surgical corridor. Moreover, patients experience limited morbidity and can tolerate early oral intake after transnasal endoscopic odontoidectomy. Essential to the successful undertaking of these endoscopic adventures is 1) an understanding of the endoscopic nasal, skull base, and neurovascular anatomy; 2) advanced and extended-length instrumentation including navigation; and 3) a team approach between experienced rhinologists and spine surgeons comfortable with endoscopic skull base techniques

Abstract 292: Predictors Of Heart Failure Readmission Rates, A Stanford Experience

Introduction: The prevalence of heart failure (HF) is approximately 5.8 million, one in every five Medicare patients with HF are readmitted within 30 days. Heart failure readmissions cost 17.4 billion dollars annually. A major focus of health policy reform has been to contain costs by preventing readmission. Medicare has proposed criteria for HF reimbursement among which are readmissions within a 30-day period after the index hospitalization will not be reimbursed. The Medicare core measure aggregate has been sparsely validated in the literature and such validation of the core measures is essential. The aim of our study was to evaluate the predictive value of the Medicare core measure aggregate and if this aggregate is an effective proposed benchmark in reduction of HF readmission.

Methods: A database was developed using RedCap (Research Electronic Data Capture), to study all patients admitted to Stanford Hospital and Clinics from September 2011 through January 2012. Inclusion criteria included those with a primary or secondary diagnosis of heart failure. Cardiac variables of interest beyond the core measures included among others, demographics, length of stay, and past medical history. Aggregate data from the Redcap database was analyzed by standard methods.

Results: 101 patients were indexed during the retrospective cohort analysis. 100 were discharged alive. The overall 30-day readmission rate was 14%. There was no difference in readmission rates between patients who had core measures completed versus those who did not (13.8% vs. 14.3%; p= 0.944). In univariate Chi-square analyses, a phone call to the patient by a nurse within 24-48 hours post discharge was associated with significant reduction in rehospitalization rates (7.1% vs. 22.7%; p=0.026). Patients who were readmitted were found to have significantly more prior hospital admissions (3.0 +/- 2 vs. 1.7 +/- 2; p = 0.011) and prior ED visits (1.6 +/- 2 vs. 3.1 +/- 2; p=0.008). In multivariate logistic regression analysis, the phone call was associated with a 75% reduction in readmission (adjusted odds ratio = 0.254, 95% CI 0.066-0.981; p= 0.047). The predictor variable, systolic dysfunction (EF < 55%) approached significance, with an adjusted odds ratio of 6.962, 95% CI 0.979-49.5; p 0.052.

Conclusions: High readmission rates for HF are present despite advances in its management. The achievement of Medicare core measure variables was not associated with a reduction in 30-day HF readmission. The reasons for this finding are still unclear, perhaps hospitalizations are in need to meet Medicare core measure guidelines rather then tailor the discharge care of each patient. It is unexpected and noteworthy that a phone call made by a nurse to the patient post discharge was associated with a 75% reduction in 30-day readmission rates. Predictors of HF readmission remain complex and an ideal aggregate for predictors in readmission have yet to be defined.

Abstract 5007: Delineating human fetal CNS stem cell hierarchy reveals a progenitor cell of origin for human Gliobastoma Multiforme

Glioblastoma Multiforme (GBM) is the most common and highly aggressive human brain tumor. Even with great advancement of surgical procedures and treatment regimens with radiation and chemotherapy, malignant gliomas remain incurable. This is due to their resistance to all conventional therapies and the diffuse infiltrative nature of the tumor cells, which makes complete tumor resection impossible. One of the major difficulties for the identification of the cell of origin for gliomas is the complex cellular composition of this disease. It is now hypothesized that the different subtypes of high-grade glioma may have different cell of origin and in mouse models it has been shown that the cell of origin resides within the progenitor populations. In order to identify the cell of origin we decided to first dissect out the various stages of CNS stem cell differentiation. After testing a panel of 34 antibodies to prospectively isolate neurospheres forming cells from human fetal brain tissue we identified a panel of four antibodies (i.e CD15, Notch1, EGFR, and CD90). Subpopulations of cells derived after FACS were analyzed for single cell lineage potency and the ability to generate neurospheres. Using an in-vitro limiting dilution assay, we ascertained that double-positive (DP; CD15+Notch1+EGFR-CD90-)) populations have the highest frequency of self-renewing cells, followed by quadruple-positive (QP) populations (CD15+Notch1+EGFR-CD90-). In-vitro differentiation assays reveal both DP and QP to be multipotent in nature however serial passaging showed that only the DP cells have a consistent self-renewing capacity, whereas QP derived cells were unable to survive after 5-6 passages.

In glioma samples however we observed by limiting dilution and serial passaging assays that the tumorsphere forming frequency was predominant in the QP population and not in the DP populations. Furthermore the GBM derived DP cells serially passaged if grown under normal neural stem cell growth condition suggesting that this population is still at a pre-malignant state. In-vivo tumorigenic assay via orthotopic implation of as few as a 1000 cells into mouse brain showed significantly higher tumor formation from the QP cells and not in the DP cells. Taken together our data suggests the presence of “normal” or pre-malignant stem cells in glioblastoma, which suggests a possible mechanism of relapse. These pre-malignant cells could comprise a cellular reservoir that may need to be targeted for future therapies.

Citation Format: Siddhartha S. Mitra, Sharareh Gholamin, Abdullah Feroze, Samuel H. Cheshier, Irving L. Weissman. Delineating human fetal CNS stem cell hierarchy reveals a progenitor cell of origin for human Gliobastoma Multiforme. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5007. doi:10.1158/1538-7445.AM2013-5007

Abstract TMP40: Revascularization in Patients with Moyamoya Decreases Abnormally High Posterior Circulation Arterial Flows Measured by Quantitative Magnetic Resonance Angiography

Introduction: Moyamoya disease and syndrome are well known to affect the anterior cerebral circulation by progressive steno-occlusive disease of the supraclinoid internal carotid arteries. Less attention has been paid to changes in posterior arterial circulation hemodynamics in this condition. We sought to better understand the latter by using a relatively novel non-invasive imaging technique: quantitative magnetic resonance angiography (qMRA).

Hypothesis: We assessed the utility of qMRA to detect changes in arterial posterior arterial circulation flows before and after surgical revascularization.

Methods: Retrospective review of patients who met the following inclusion criteria: (1) diagnosis of moyamoya disease or syndrome with revascularization surgery at the Stanford University between September 2008 and March 2012; (2) preoperative and postoperative qMRA scans on record within a two-year time frame; and (3) high-quality qMRA images without motion artifact. Cerebral blood-vessel flow was quantified after non-contrast magnetic resonance imaging through the use of a commercially available software tool: non-invasive optimal vessel analysis (NOVA, VasSol, Chicago, USA).

Results: A total of 191 patients underwent 281 surgeries in this period of time. Of these, a cohort of 64 patients (78% female, mean age 38.5 years, 55% unilateral disease) had preoperative and postoperative qMRA studies. Preoperative arterial flows in the posterior circulation were markedly elevated compared to normative data. These flows significantly decreased after revascularization (94% direct STA-MCA bypass): right posterior cerebral artery 145 ml/min pre-surgery, 123 ml/min post-surgery, p=0.005; basilar artery 264 ml/min pre-surgery, 222ml/min post-surgery, p=0.0038.

Conclusion: Quantitative MRA shows that posterior circulation arterial flows are markedly increased in patients with moyamoya. After revascularization, there is an overall decrease in these flows that is significant in the basilar artery and right posterior cerebral artery. Further use of qMRA might be warranted to better understand moyamoya hemodynamics before and after surgery.

Dental amalgam: effects of alloy/mercury mixing ratio, uses and waste management

BACKGROUND

Silver dental amalgam is one of the oldest filling materials used in dentistry. The American Dental Association (ADA) has estimated that billions of amalgam restorations have been placed in patients in the last 150 years. Due to the presence of mercury and mishandling during the filling make it more controversial. The objective of this study was to conduct a survey of the use of different brands and to assess any deviations in practice from the hand mixing manual method of elemental mercury and alloy in a pestle/mortar and encapsulated form.

METHODS

A questionnaire was sent to 250 of randomly selected dental practitioner in various localities of Karachi. Data was analysed to record the specified brands used along with their powder/liquid (P/L) ratio and the different methods for disposing off mercury in this study.

RESULTS

The most commonly used form of dispensing method was hand mixing (57%) and only 30% of the dentists followed the manufacturer instruction for hand mixing ratio.Eighty-seven percent of dental amalgam restoration was performed and 13% removed by the dentist per month and the method of disposing the amalgam wastage that 55%, 25%, and 20% dentists were used the sink, bin and other methods respectively in their dental clinics.

CONCLUSION

Amalgam restoration is still popular filling material in the posterior region of the mouth but we need to create awareness among the dentists who do not follow the ADA specifications.