Parallel Multichannel Assessment of Rotationally Manipulated Magnetic Nanoparticles

Background

Rotational manipulation of chains or clusters of magnetic nanoparticles (MNPs) offers a means for directed translation and payload delivery that should be explored for clinical use. Multiple MNP types are available, yet few studies have performed side-by-side comparisons to evaluate characteristics such as velocity, movement at a distance, and capacity for drug conveyance or dispersion.

Purpose

Our goal was to design, build, and study an electric device allowing simultaneous, multichannel testing (e.g., racing) of MNPs in response to a rotating magnetic field. We would then select the “best” MNP and use it with optimized device settings, to transport an unbound therapeutic agent.

Methods

A magnetomotive system was constructed, with a Helmholtz pair of coils on either side of a single perpendicular coil, on top of which was placed an acrylic tray having multiple parallel lanes. Five different MNPs were tested: graphene-coated cobalt MNPs (TurboBeads™), nickel nanorods, gold-iron alloy MNPs, gold-coated Fe₃O₄ MNPs, and uncoated Fe₃O₄ MNPs. Velocities were determined in response to varying magnetic field frequencies (5–200 Hz) and heights (0–18 cm). Velocities were normalized to account for minor lane differences. Doxorubicin was chosen as the therapeutic agent, assayed using a CLARIOstar Plus microplate reader.

Results

The MMS generated a maximal MNP velocity of 0.9 cm/s. All MNPs encountered a “critical” frequency at 20–30 Hz. Nickel nanorods had the optimal response based on tray height and were then shown to enable unbound doxorubicin dispersion along 10.5 cm in <30 sec.

Conclusion

A rotating magnetic field can be conveniently generated using a three-coil electromagnetic device, and used to induce rotational and translational movement of MNP aggregates over mesoscale distances. The responses of various MNPs can be compared side-by-side using multichannel acrylic trays to assess suitability for drug delivery, highlighting their potential for further in vivo applications.

Soft Capsule Magnetic Millirobots for Region-Specific Drug Delivery in the Central Nervous System

Small soft robotic systems are being explored for myriad applications in medicine. Specifically, magnetically actuated microrobots capable of remote manipulation hold significant potential for the targeted delivery of therapeutics and biologicals. Much of previous efforts on microrobotics have been dedicated to locomotion in aqueous environments and hard surfaces. However, our human bodies are made of dense biological tissues, requiring researchers to develop new microrobotics that can locomote atop tissue surfaces. Tumbling microrobots are a sub-category of these devices capable of walking on surfaces guided by rotating magnetic fields. Using microrobots to deliver payloads to specific regions of sensitive tissues is a primary goal of medical microrobots. Central nervous system (CNS) tissues are a prime candidate given their delicate structure and highly region-specific function. Here we demonstrate surface walking of soft alginate capsules capable of moving on top of a rat cortex and mouse spinal cord ex vivo, demonstrating multi-location small molecule delivery to up to six different locations on each type of tissue with high spatial specificity. The softness of alginate gel prevents injuries that may arise from friction with CNS tissues during millirobot locomotion. Development of this technology may be useful in clinical and preclinical applications such as drug delivery, neural stimulation, and diagnostic imaging.

Harnessing cerebrospinal fluid circulation for drug delivery to brain tissues

Initially thought to be useful only to reach tissues in the immediate vicinity of the CSF circulatory system, CSF circulation is now increasingly viewed as a viable pathway to deliver certain therapeutics deeper into brain tissues. There is emerging evidence that this goal is achievable in the case of large therapeutic proteins, provided conditions are met that are described herein. We show how fluid dynamic modeling helps predict infusion rate and duration to overcome high CSF turnover. We posit that despite model limitations and controversies, fluid dynamic models, pharmacokinetic models, preclinical testing, and a qualitative understanding of the glymphatic system circulation can be used to estimate drug penetration in brain tissues. Lastly, in addition to highlighting landmark scientific and medical literature, we provide practical advice on formulation development, device selection, and pharmacokinetic modeling. Our review of clinical studies suggests a growing interest for intra-CSF delivery, particularly for targeted proteins.

Targeted sonodynamic destruction of glioblastoma cells using antibody-titanium dioxide nanoparticle conjugates

Aim: We present data on sonodynamic therapy (SDT) against glioblastoma cells utilizing titanium dioxide (TiO₂) nanoparticles conjugated to anti-EGFR antibody. Materials & methods: TiO₂ nanoparticles were bound to anti-EGFR antibody to form antibody-nanoparticle conjugates (ANCs), then characterized by x-ray photoelectron spectroscopy and transmission electron microscopy. Cells underwent ultrasound and assessment on viability, reactive oxygen species and apoptosis were performed. Results: X-ray photoelectron spectroscopy analysis revealed the formation of an ANC. Transmission electron microscopy showed internalization of the ANCs by glioblastoma cells. With SDT, cell viabilities were reduced in the presence of ANCs, reactive oxygen species production was formed, but minimal effect on apoptosis was seen. Conclusion: For the first time, an ANC can be used with SDT to kill glioblastoma cells.

Etoposide-Bound Magnetic Nanoparticles Designed for Remote Targeting of Cancer Cells Disseminated Within Cerebrospinal Fluid Pathways

Magnetic nanoparticles (MNPs) have potential for enhancing drug delivery in selected cancer patients, including those which have cells that have disseminated within cerebrospinal fluid (CSF) pathways. Here, we present data related to the creation and in vitro use of new two-part MNPs consisting of magnetic gold-iron alloy cores which have streptavidin binding sites, and are coated with biotinylated etoposide. Etoposide was chosen due to its previous use in the CSF and ease of biotinylation. Etoposide magnetic nanoparticles (“Etop-MNPs”) were characterized by several different methods, and moved at a distance by surface-walking of MNP clusters, which occurs in response to a rotating permanent magnet. Human cell lines including D283 (medulloblastoma), U138 (glioblastoma), and H2122 (lung adenocarcinoma) were treated with direct application of Etop-MNPs (and control particles), and after remote particle movement. Cell viability was determined by MTT assay and trypan blue exclusion. Results indicated that the biotinylated etoposide was successfully bound to the base MNPs, with the hybrid particle attaining a maximum velocity of 0.13 ± 0.018 cm/sec. Etop-MNPs killed cancer cells in a dose-dependent fashion, with 50 ± 6.8% cell killing of D283 cells (for example) with 24 h of treatment after remote targeting. U138 and H2122 cells were found to be even more susceptible to the killing effect of Etop-MNPs than D283 cells. These findings indicate that the novel Etop-MNPs have a cytotoxic effect, and can be moved relatively rapidly at physiologic distances, using a rotating magnet. While further testing is needed, intrathecal administration of Etop-MNPs holds promise for magnetically-enhanced eradication of cancer cells distributed within CSF pathways, particularly if given early in the course of the disease.

Cerebral Microdialysis as a Tool for Assessing the Delivery of Chemotherapy in Brain Tumor Patients

The development of curative treatment for glioblastoma has been extremely challenging. Chemotherapeutic agents that have seemed promising have failed in clinical trials. Drugs that can successfully target cancer cells within the brain must first traverse the brain interstitial fluid. Cerebral microdialysis (CMD) is an invasive technique in which interstitial fluid can be directly sampled. CMD has primarily been used clinically in the setting of head trauma and subarachnoid hemorrhage. Our goal was to review the techniques, principles, and new data pertaining to CMD to highlight its use in neuro-oncology. We conducted a literature search using the PubMed database and selected studies in which the investigators had used CMD in either animal brain tumor models or clinical trials. The references were reviewed for additional information. Studies of CMD have shown its importance as a neurosurgical technique. CMD allows for the collection of pharmacokinetic data on drug penetrance across the blood-brain barrier and metabolic data to characterize the response to chemotherapy. Although no complications have been reported, the current CMD technique (as with any procedure) has risks and limitations, which we have described in the present report. Animal CMD experiments have been used to exclude central nervous system drug candidates from progressing to clinical trials. At present, patients undergoing CMD have been monitored in the intensive care unit, owing to the requisite tethering to the apparatus. This can be expected to change soon because of advances in microminiaturization. CMD is an extremely valuable, yet underused, technique. Future CMD applications will have central importance in assessing drug delivery to tumor cells in vivo, allowing a pathway to successful therapy for malignant brain tumors.

Rotating Magnetic Nanoparticle Clusters as Microdevices for Drug Delivery

BACKGROUND

Magnetic nanoparticles (MNPs) hold promise for enhancing delivery of therapeutic agents, either through direct binding or by functioning as miniature propellers. Fluid-filled conduits and reservoirs within the body offer avenues for MNP-enhanced drug delivery. MNP clusters can be rotated and moved across surfaces at clinically relevant distances in response to a rotating magnet. Limited data are available regarding issues affecting MNP delivery by this mechanism, such as adhesion to a cellular wall. Research reported here was initiated to better understand the fundamental principles important for successful implementation of rotational magnetic drug targeting (rMDT).

METHODS

Translational movements of four different iron oxide MNPs were tested, in response to rotation (3 Hz) of a neodymium-boron-iron permanent magnet. MNP clusters moved along biomimetic channels of a custom-made acrylic tray, by surface walking. The effects of different distances and cellular coatings on MNP velocity were analyzed using videography. Dyes (as drug surrogates) and the drug etoposide were transported by rotating MNPs along channels over a 10 cm distance.

RESULTS

MNP translational velocities could be predicted from magnetic separation times. Changes in distance or orientation from the magnet produced alterations in MNP velocities. Mean velocities of the fastest MNPs over HeLa, U251, U87, and E297 cells were 0.24 ± 0.02, 0.26 ± 0.02, 0.28 ± 0.01, and 0.18 ± 0.03 cm/sec, respectively. U138 cells showed marked MNP adherence and an 87.1% velocity reduction at 5.5 cm along the channel. Dye delivery helped visualize the effects of MNPs as microdevices for drug delivery. Dye delivery by MNP clusters was 21.7 times faster than by diffusion. MNPs successfully accelerated etoposide delivery, with retention of chemotherapeutic effect.

CONCLUSION

The in vitro system described here facilitates side-by-side comparisons of drug delivery by rotating MNP clusters, on a human scale. Such microdevices have the potential for augmenting drug delivery in a variety of clinical settings, as proposed.

Tumor Development and Angiogenesis in Adult Brain Tumor: Glioblastoma

Angiogenesis is the growth of new capillaries from the preexisting blood vessels. Glioblastoma (GBM) tumors are highly vascularized tumors, and glioma growth depends on the formation of new blood vessels. Angiogenesis is a complex process involving proliferation, migration, and differentiation of vascular endothelial cells (ECs) under the stimulation of specific signals. It is controlled by the balance between its promoting and inhibiting factors. Various angiogenic factors and genes have been identified that stimulate glioma angiogenesis. Therefore, attention has been directed to anti-angiogenesis therapy in which glioma proliferation is inhibited by inhibiting the formation of new tumor vessels using angiogenesis inhibitory factors and drugs. Here, in this review, we highlight and summarize the various molecular mediators that regulate GBM angiogenesis with focus on recent clinical research on the potential of exploiting angiogenic pathways as a strategy in the treatment of GBM patients.

An in vitro Model System for Evaluating Remote Magnetic Nanoparticle Movement and Fibrinolysis

Background

Thrombotic events continue to be a major cause of morbidity and mortality worldwide. Tissue plasminogen activator (tPA) is used for the treatment of acute ischemic stroke and other thrombotic disorders. Use of tPA is limited by its narrow therapeutic time window, hemorrhagic complications, and insufficient delivery to the location of the thrombus. Magnetic nanoparticles (MNPs) have been proposed for targeting tPA delivery. It would be advantageous to develop an improved in vitro model of clot formation, to screen thrombolytic therapies that could be enhanced by addition of MNPs, and to test magnetic drug targeting at human-sized distances.

Methods

We utilized commercially available blood and endothelial cells to construct 1/8th inch (and larger) biomimetic vascular channels in acrylic trays. MNP clusters were moved at a distance by a rotating permanent magnet and moved along the channels by surface walking. The effect of different transport media on MNP velocity was studied using video photography. MNPs with and without tPA were analyzed to determine their velocities in the channels, and their fibrinolytic effect in wells and the trays. 

Results

MNP clusters could be moved through fluids including blood, at human-sized distances, down straight or branched channels, using the rotating permanent magnet. The greatest MNP velocity was closest to the magnet: 0.76 ± 0.03 cm/sec. In serum, the average MNP velocity was 0.10 ± 0.02 cm/sec. MNPs were found to enhance tPA delivery, and cause fibrinolysis in both static and dynamic studies. Fibrinolysis was observed to occur in 85% of the dynamic MNP + tPA experiments.

Conclusion

MNPs hold great promise for use in augmenting delivery of tPA for the treatment of stroke and other thrombotic conditions. This model system facilitates side by side comparisons of MNP-facilitated drug delivery, at a human scale.

Abstract 4661: Magnetic nanoparticles (MNPs) for cancer drug delivery: The value of in vitro modeling

BACKGROUND: Magnetic nanoparticles (MNPs) have attracted great interest for use as delivery vehicles for cancer and other diseases due to their ability to be functionalized and localized using external magnets. In the presence of a magnetic field, individual MNPs form aggregates, which in turn can be made to spin and surface walk, in response to rotation of the field. Here, we present data from the use of a in vitro model system, which is useful in mimicking the various conditions and distances that MNP-drug combinations may encounter in vivo. METHODS: A sterilizable acrylic tray was designed, which has 1/8th inch wide lanes and can be used with or without the addition of cultured cells. The tray is compatible with standard plate readers, and the lanes can be modified to mimic various conduits within the body. In studies described here, glioma cell lines and normal vascular endothelial cells were used in the tray. In order to test the effect of fluid viscosity on MNP velocity in response to the rotating magnetic field, lanes were filled with 1mL of PBS, culture medium, serum, or whole blood. Pre-magnetized and unmagnetized MNPs were aliquoted into the lanes at volumes from 10 - 100 uL. T-PA and trypan blue were used as a model drugs. Velocities of MNP aggregates were determined by videography at five different tray positions relative to the magnet: centered, offset, push, pull, and below. Particle adhesion to cells could be quantified using ImageJ. RESULTS: Using the model system, greater MNP velocities were achieved with pre-magnetization, and larger aliquots. For example, 100ul aliquots had a total average velocity 1.27± 0.21 times that of 20ul. MNP velocity was found to be inversely -related to fluid viscosity, but particles could be moved magnetically even through whole blood. Test drugs could be successfully delivered by convection, even without prior binding to MNPs. MNP velocity also varied according to magnet position, with speeds up to 0.75 +/- 0.05 cm/sec in the pull (fastest) position. In the offset position, a distance of 20 cm above the magnet produced the greatest velocity. MNPs moved more slowly over confluent monolayers of endothelial or glioma cells (with greater adhesion), but a mean velocity of 0.25 cm/sec +/- 0.03 cm was typically observed. CONCLUSIONS: In vitro modeling is extremely helpful in predicting the behavior of particles intended for clinical use in magnetically-enhanced drug delivery. The velocity and cell surface adhesion of MNP aggregates can be quantified, and the effect of factors - such as fluid viscosity, cell type, and position with respect to the magnet - analyzed in order to better understand the advantages and limitations of this technology.

Citation Format: Sebastian P. Pernal, Alexander J. Willis, Herbert H. Engelhard. Magnetic nanoparticles (MNPs) for cancer drug delivery: The value of in vitro modeling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4661.

Abstract 1424: Elucidating the microRNA-203 specific biological processes in glioblastoma cells from high-throughput RNA-sequencing

Glioblastoma (GBM) is the most common primary malignant intracranial adult brain tumor. Allelic deletion on chromosome 14q play an essential role in GBM pathogenesis, and this chromosome 14q site was thought to harbor multiple tumor suppressor gene associated with GBM, a region that also encodes microRNA-203 (miR-203). This study was conducted to identify gene expression profile changes associated with mir-203 expression by high-throughput RNA sequencing. Enrichment analyses for gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis revealed that mir-203 expression had a strong, negative effect on a number of fundamental and interconnected biological processes involved in cell growth and proliferation. The biological processes mostly influenced were p53 signaling pathway, FoxO signaling pathway, DNA replication, cell cycle, MAPK signaling pathway and Apoptosis. In total, 847 upregulated and 345 downregulated differentially expressed genes (DEGs) were identified in control versus miR203 expressing glioma cells. After GO enrichment, the downregulated DEGs and miR-203 predicted target genes such as BCL-2, SPARC, PDGFA, CREB were found to be mainly enriched in cell cycle regulation and apoptosis processes, whereas the upregulated DEGs, such as CCND1, E2F1 were involved in the DNA replication and cell cycle regulation of gene expression. We also demonstrate that mir-203 expression suppressed BCL-2 protein and mRNA by western blotting and qRT-PCR analysis. Moreover, co-transfection experiments using a luciferase-based reporter assay demonstrated that mir-203 directly regulated BCL-2 expression and BCL-2 overexpression suppressed mir-203 mediated cell death. Knowledge gained through this profiling study can facilitate targeted therapeutic interventions.

Citation Format: Bhavesh K. Ahir, Herbert H. Engelhard, Sajani S. Lakka. Elucidating the microRNA-203 specific biological processes in glioblastoma cells from high-throughput RNA-sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1424.

MicroRNAs in glioblastoma pathogenesis and therapy: A comprehensive review

Glioblastoma (GBM), also known as grade IV astrocytoma, is the most aggressive primary intracranial tumor of the adult brain. MicroRNAs (miRNAs), a class of small non-coding RNA species, have critical functions across various biological processes. A great deal of progress has been made recently in dissecting miRNA pathways associated with the pathogenesis of GBM. miRNA expression signatures called gene signatures also characterize and contribute to the phenotypic diversity of GBM subclasses through their ability to regulate developmental growth and differentiation. miRNA molecules have been identified as diagnostic and prognostic biomarkers for patient stratification and may also serve as therapeutic targets and agents. This review summarizes: (i) the current understanding of the roles of miRNAs in the pathogenesis of GBM, (ii) the potential use of miRNAs in GBM diagnosis and glioma grading, (iii) further prospects of developing miRNAs as novel biomarkers and therapeutic targets for GBM, and (iv) important practical considerations when considering miRNA therapy for GBM patients.

A fractional motion diffusion model for grading pediatric brain tumors

Objectives

To demonstrate the feasibility of a novel fractional motion (FM) diffusion model for distinguishing low- versus high-grade pediatric brain tumors; and to investigate its possible advantage over apparent diffusion coefficient (ADC) and/or a previously reported continuous-time random-walk (CTRW) diffusion model.

Materials and methods

With approval from the institutional review board and written informed consents from the legal guardians of all participating patients, this study involved 70 children with histopathologically-proven brain tumors (30 low-grade and 40 high-grade). Multi-b-value diffusion images were acquired and analyzed using the FM, CTRW, and mono-exponential diffusion models. The FM parameters, D_fm, φ, ψ (non-Gaussian diffusion statistical measures), and the CTRW parameters, D_m, α, β (non-Gaussian temporal and spatial diffusion heterogeneity measures) were compared between the low- and high-grade tumor groups by using a Mann-Whitney-Wilcoxon U test. The performance of the FM model for differentiating between low- and high-grade tumors was evaluated and compared with that of the CTRW and the mono-exponential models using a receiver operating characteristic (ROC) analysis.

Results

The FM parameters were significantly lower (p < 0.0001) in the high-grade (D_fm: 0.81 ± 0.26, φ: 1.40 ± 0.10, ψ: 0.42 ± 0.11) than in the low-grade (D_fm: 1.52 ± 0.52, φ: 1.64 ± 0.13, ψ: 0.67 ± 0.13) tumor groups. The ROC analysis showed that the FM parameters offered better specificity (88% versus 73%), sensitivity (90% versus 82%), accuracy (88% versus 78%), and area under the curve (AUC, 93% versus 80%) in discriminating tumor malignancy compared to the conventional ADC. The performance of the FM model was similar to that of the CTRW model.

Conclusions

Similar to the CTRW model, the FM model can improve differentiation between low- and high-grade pediatric brain tumors over ADC.

•

The fractional motion (FM) diffusion model was applied to pediatric brain tumors.

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The FM model parameters can be sensitive to tissue microstructures.

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The FM model outperforms the mono-exponential diffusion model.

•

The FM model performs similarly to the continuous-time random-walk (CTRW) model.

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Our results challenge those from recent biophysics studies in cell cultures.

Intramedullary spinal cord tumors: a review of current and future treatment strategies

Intramedullary spinal cord tumors have low incidence rates but are associated with difficult treatment options. The majority of patients with these tumors can be initially treated with an attempted resection. Unfortunately, those patients who cannot undergo gross-total resection or have subtotal resection are left with few treatment options, such as radiotherapy and chemotherapy. These adjuvant treatments, however, are associated with the potential for significant adverse side effects and still leave patients with a poor prognosis. To successfully manage these patients and improve both their quality of life and prognosis, novel treatment options must be developed to supplement subtotal resection. New research is underway investigating alternative therapeutic approaches for these patients, including directed, localized drug delivery and nanomedicine techniques. These and other future investigations will hopefully lead to promising new therapies for these devastating diseases.

An analysis of prognostic factors associated with recurrence in the treatment of atypical meningiomas

Background

There has been increased reporting of atypical meningioma (grade II) since the World Health Organization reclassification in 2000, and the use of postoperative radiation therapy (RT) in the treatment of these tumors is controversial. We evaluated patients treated at our institution to identify patient subgroups with increased risk of recurrence that may benefit from adjuvant RT.

Methods and materials

We retrospectively assessed 50 patients treated for World Health Organization grade II meningiomas between March 2000 and February 2013. Sex, race, age of diagnosis, tumor location, performance status, size of tumor, MIB-1 index, resection status, and RT were recorded. Patient follow-up, recurrence, and vital status were measured to assess 3-year overall survival (OS) and recurrence free survival (RFS).

Results

The median follow-up was 37 months (range, 1-148). Female sex was associated with decreased RFS compared with male sex (86.1% vs 100%, P = .047). Subtotal resection demonstrated both inferior RFS (67.5% vs 96.6%, P = .025) and OS compared with gross total resection (70.0% vs 100%, P < .001). Tumors >4.5 cm had worse RFS than tumors ≤4.5 cm (85.4% vs 100%, P = .025). Patient OS was lower in tumors with an MIB-1 index >5% than ≤5% (89.7% vs 100%, P = .008). Eastern Cooperative Oncology Group 2-4 negatively impacted OS relative to patients with an Eastern Cooperative Oncology Group 0-1 (66.7% vs 100%, P < .001).

Conclusions

Significantly higher rates of recurrence occurred in female sex, subtotal resection, and tumors larger than 4.5 cm. Further studies are needed to confirm these findings and determine whether patients without any of these risk factors can undergo surgical resection without adjuvant radiation therapy.

Maintenance Therapy With Tumor-Treating Fields Plus Temozolomide vs Temozolomide Alone for Glioblastoma: A Randomized Clinical Trial

IMPORTANCE

Glioblastoma is the most devastating primary malignancy of the central nervous system in adults. Most patients die within 1 to 2 years of diagnosis. Tumor-treating fields (TTFields) are a locoregionally delivered antimitotic treatment that interferes with cell division and organelle assembly.

OBJECTIVE

To evaluate the efficacy and safety of TTFields used in combination with temozolomide maintenance treatment after chemoradiation therapy for patients with glioblastoma.

DESIGN, SETTING, AND PARTICIPANTS

After completion of chemoradiotherapy, patients with glioblastoma were randomized (2:1) to receive maintenance treatment with either TTFields plus temozolomide (n = 466) or temozolomide alone (n = 229) (median time from diagnosis to randomization, 3.8 months in both groups). The study enrolled 695 of the planned 700 patients between July 2009 and November 2014 at 83 centers in the United States, Canada, Europe, Israel, and South Korea. The trial was terminated based on the results of this planned interim analysis.

INTERVENTIONS

Treatment with TTFields was delivered continuously (>18 hours/day) via 4 transducer arrays placed on the shaved scalp and connected to a portable medical device. Temozolomide (150-200 mg/m2/d) was given for 5 days of each 28-day cycle.

MAIN OUTCOMES AND MEASURES

The primary end point was progression-free survival in the intent-to-treat population (significance threshold of .01) with overall survival in the per-protocol population (n = 280) as a powered secondary end point (significance threshold of .006). This prespecified interim analysis was to be conducted on the first 315 patients after at least 18 months of follow-up.

RESULTS

The interim analysis included 210 patients randomized to TTFields plus temozolomide and 105 randomized to temozolomide alone, and was conducted at a median follow-up of 38 months (range, 18-60 months). Median progression-free survival in the intent-to-treat population was 7.1 months (95% CI, 5.9-8.2 months) in the TTFields plus temozolomide group and 4.0 months (95% CI, 3.3-5.2 months) in the temozolomide alone group (hazard ratio [HR], 0.62 [98.7% CI, 0.43-0.89]; P = .001). Median overall survival in the per-protocol population was 20.5 months (95% CI, 16.7-25.0 months) in the TTFields plus temozolomide group (n = 196) and 15.6 months (95% CI, 13.3-19.1 months) in the temozolomide alone group (n = 84) (HR, 0.64 [99.4% CI, 0.42-0.98]; P = .004).

CONCLUSIONS AND RELEVANCE

In this interim analysis of 315 patients with glioblastoma who had completed standard chemoradiation therapy, adding TTFields to maintenance temozolomide chemotherapy significantly prolonged progression-free and overall survival.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00916409.

Response assessment of NovoTTF-100A versus best physician's choice chemotherapy in recurrent glioblastoma

The NovoTTF-100A device emits frequency-tuned alternating electric fields that interfere with tumor cell mitosis. In phase III trial for recurrent glioblastomas, NovoTTF-100A was shown to have equivalent efficacy and less toxicity when compared to Best Physician's Choice (BPC) chemotherapy. We analyzed the characteristics of responders and nonresponders in both cohorts to determine the characteristics of response and potential predictive factors. Tumor response and progression were determined by Macdonald criteria. Time to response, response duration, progression-free survival (PFS) ± Simon–Makuch correction, overall survival (OS), prognostic factors, and relative hazard rates were compared between responders and nonresponders. Median response duration was 7.3 versus 5.6 months for NovoTTF-100A and BPC chemotherapy, respectively (P = 0.0009). Five of 14 NovoTTF-100A responders but none of seven BPC responders had prior low-grade histology. Mean cumulative dexamethasone dose was 35.9 mg for responders versus 485.6 mg for nonresponders in the NovoTTF-100A cohort (P < 0.0001). Hazard analysis showed delayed tumor progression in responders compared to nonresponders. Simon–Makuch-adjusted PFS was longer in responders than in nonresponders treated with NovoTTF-100A (P = 0.0007) or BPC chemotherapy (P = 0.0222). Median OS was longer for responders than nonresponders treated with NovoTTF-100A (P < 0.0001) and BPC chemotherapy (P = 0.0235). Pearson analysis showed strong correlation between response and OS in NovoTTF-100A (P = 0.0002) but not in BPC cohort (P = 0.2900). Our results indicate that the response characteristics favor NovoTTF-100A and data on prior low-grade histology and dexamethasone suggest potential genetic and epigenetic determinants of NovoTTF-100A response.

An analysis of radiation necrosis of the central nervous system treated with bevacizumab

Radiation necrosis is a devastating complication following radiation to the central nervous system. The purpose of this study was to perform a comprehensive analysis of cases in the literature using bevacizumab, a monoclonal antibody against vascular endothelial growth factor, as treatment for radiation necrosis. A MEDLINE/PubMed search of articles about the use of bevacizumab for radionecrosis treatment yielded 16 studies published between 2007 and 2012. Data was summarized according to patient characteristics, treatment received and outcomes measured. A total of 71 unique cases were identified that met the inclusion criteria. The median age at the time of treatment with bevacizumab was 47 years. The most common tumors treated were glioblastoma (31 %), anaplastic glioma (14 %), and metastatic brain tumors (15 %). The median time from ending radiotherapy to starting treatment with bevacizumab was 11 months and the median follow up time after bevacizumab treatment was 8 months. The median number of cycles of bevacizumab was administered was 4, and the median dosage of bevacizumab was 7.5 mg/kg. The median time elapsed between cycles of bevacizumab was 2 weeks. Overall, pre and post treatment imaging revealed a median decrease in T1 contrast enhancement of 63 %, and a 59 % median decrease in T2/FLAIR signal abnormality. Treatment with bevacizumab resulted in a significant radiographic response for patients with radionecrosis. The median dosage of bevacizumab of 7.5 mg/kg for four cycles every 2 weeks should be considered as a treatment option in this patient population.

Response assessment of novoTTF-100A versus best physician’s choice chemotherapy in recurrent glioblastoma

2080

Background: The NovoTTF-100A device emits tumor treating electric fields and was tested against Best Physician’s Choice (BPC) chemotherapy in a randomized phase III trial. We analyzed post hoc the characteristics of responders and non-responders in both cohorts. Methods: Macdonald criteria were used to determine tumor response and progression. Kaplan-Meier and Chi-squared statistics were computed for time to response, response duration, progression-free survival (PFS) with and without Simon-Makuch correction, and overall survival (OS). Prognostic factors were compared using the Wilconox rank sum test. Relative hazard rates for responders and non-responders were plotted. Results: The median response duration was 7.3 versus 5.6 months for NovoTTF-100A and BPC chemotherapy respectively (p=0.0009). Five of 14 NovoTTF-100A responders but none of 7 BPC responders had prior low-grade histology. The mean cumulative dexamethasone dose was 35.9 mg for responders versus 485.6 mg for non-responders in the NovoTTF-100A cohort (p<0.0001) as compared to 525.6 mg for responders and 431.0 mg for non-responders in the BPC cohort (p=0.9520). Hazard rate analysis showed delayed tumor progression in responders compared to non-responders. The Simon-Makuch conditional plot, which adjusted for unequal progression-free states, still showed longer PFS in responders than non-responders treated with NovoTTF-100A (χ2=11.5, P=0.0007) or BPC chemotherapy (χ2=5.2, P=0.0222). The median OS was 24.8 months for responders that is longer than 6.2 months for non-responders treated with NovoTTF-100A (χ2=25.7, P<0.0001). In the BPC chemotherapy cohort, the median OS was 20.0 months for responders and 6.8 months for non-responders (χ2=5.1, P=0.0235). There was strong Pearson correlation between response and OS in NovoTTF-100A (P<0.0002) but not in BPC cohort (P=0.2952). Conclusions: Response duration, adjusted Simon-Makuch PFS and OS favor NovoTTF-100A over BPC chemotherapy. Data on prior low-grade histology and dexamethasone dose suggest potential genetic and epigenetic determinants of NovoTTF-100A response. Clinical trial information: NCT00379470.

Heterogeneity of HDAC3 expression and its modulation by valproic acid in glioblastoma cells

e13038

Background: Glioblastoma (gbm) is a devastating malignancy and a therapeutic challenge. Our group and others have observed long-term gbm survivors treated with valproic acid (VPA), a histone deacetylase (HDAC) inhibitor. While in vitro studies of HDAC inhibitors have been promising, clinical trials and retrospective analyses have been disappointing. We hypothesize that HDAC3 may be a more specific target or treatment marker for gbm. Since limited data is available pertaining to HDAC3 and its modulation in gbm, our goals were to: 1) develop methods for determining HDAC3 expression and localization in gbm cells, 2) study HDAC3 heterogeneity among different gbm cell lines, including one in low passage, and 3) test the effect of VPA treatment on HDAC3 expression of gbm cells in vitro. Methods: Three established gbm cell lines (U-87, U-251 and E297), were cultured using standard technique. HeLa cells were used as the positive HDAC3 control. Cells were stained using 2 different antibodies, and analyzed using immunofluoresence microscopy (IFM), and Western blotting (with β-actin standards). IgG was used for negative isotype controls. Cell counts, viability, and H&E staining for changes in morphology were also recorded. Lysates for Western blots were made from whole cells, nuclei, and cytoplasmic preparations. Band quantification was performed using the ImageJ software. Cells in exponential growth were treated for 48 hours with 10 mM VPA, and compared to untreated cells. Results: Untreated cells studied for HDAC3 using IFM showed nuclear and some cytoplasmic staining in all 4 lines, which varied according to cell type and morphology. Western blot analysis confirmed the variability of HDAC3 expression seen by IFM. The effect of VPA treatment on gbm HDAC3 expression (cytoplasmic and nuclear) was seen to be highly variable, ranging from marked down-modulation in some gbm cells, to minimal effect in others. Conclusions: These data provide the groundwork for studying HDAC3 levels in patients undergoing therapy with HDAC inhibitors. The effect of VPA on the HDAC3 expression of gbm cells is heterogeneous; individualized assessment of such effect will be necessary in delineating any subset of patients that may respond to VPA treatment.

Primary CNS germ cell tumors in Japan and the United States: an analysis of 4 tumor registries

Intracranial germ cell tumors (GCTs) are relatively rare. Their incidence has been considered to be higher in East Asia than in the United States. This study estimates the incidence of CNS GCTs in Japan and the United States, investigates gender discrepancies in each country, and describes treatment outcomes. Data on primary CNS GCTs from 4 databases were utilized: population-based malignant incidence data from (1) the Japan Cancer Surveillance Research Group (2004-2006; 14 registries), malignant and nonmalignant incidence data from (2) the Surveillance, Epidemiology, and End Results Program (2004-2008; 17 registries), and hospital-based observed survival data from (3) the Brain Tumor Registry of Japan (1984-2000) and (4) the US National Cancer Data Base (1990-2003). Incidence rates per 100 000 for malignant GCTs were not statistically significantly different between Japan (males = 0.143, females = 0.046) and the United States (males = 0.118, females = 0.030). The malignant incidence-rate ratio was higher for pineal GCTs versus nonpineal (ie, the rest of the brain) GCTs in Japan (11.5:1 vs 1.9:1, respectively) and the United States (16.0:1 vs 1.7:1, respectively). In general, 5-year survival estimates were high: over 75% for all GCTs, and over 81% for germinomas, regardless of the type of treatment in either Japan or the United States. The incidence of primary GCTs is similar between Japan and the United States and has the same gender-based patterns by location. High rates of survival were observed in both countries.

Unusual CNS presentation of thyroid cancer

As advanced therapies allow cancer patients to live longer, disease failure in the central nervous system increases from limited therapeutic penetration. Primary thyroid malignancies rarely metastasize to the brain and have a small number of investigations in literature on the subject. The majority of brain metastases involve the brain parenchyma, reflecting the mass and blood distribution within the brain and central nervous system. Here, we report two cases of the most common differentiated thyroid cancers; follicular thyroid cancer having brain involvement from extra-axial growth and papillary thyroid cancer having brain involvement from a single intraventricular metastasis, presumed as metastasis from the vascular choroid plexus. Both of our cases had widespread systemic involvement. For our follicular thyroid cancer, brain involvement was a result of extra-axial growth from cavarial bone, and our papillary thyroid cancer had brain involvement from a single intraventricular metastasis that was initially resected and nearly a year later developed extensive brain involvement. Unlike the usual gray-white junction metastases seen in the majority of metastatic brain tumors, including thyroid, our cases are uncommon. They reflect differences in tumor biology that allows for spread and growth in the brain. Although there is growing genetic knowledge on tumors that favor brain metastases, little is known about tumors that rarely involve the brain.

Clinical presentation, histology, and treatment in 430 patients with primary tumors of the spinal cord, spinal meninges, or cauda equina

OBJECT Patients having a primary tumor of the spinal cord, spinal meninges or cauda equina, are relatively rare. Neurosurgeons encounter and treat such patients, and need to be aware of their clinical presentation, tumor types, treatment options, and potential complications. The purpose of this paper is to report results from a series of 430 patients with primary intraspinal tumors, taken from a larger cohort of 9661 patients with primary tumors of the CNS. METHODS Extensive information on individuals diagnosed (in the year 2000) as having a primary CNS neoplasm was prospectively collected in a Patient Care Evaluation Study conducted by the Commission on Cancer of the American College of Surgeons. Data from US hospital cancer registries were submitted directly to the National Cancer Database. Intraspinal tumor cases were identified based on ICD-O-2 topography codes C70.1, C72.0, and C72.1. Analyses were performed using SPSS. RESULTS Patients with primary intraspinal tumors represented 4.5% of the CNS tumor group, and had a mean age of 49.3 years. Pain was the most common presenting symptom, while the most common tumor types were meningioma (24.4%), ependymoma (23.7%), and schwannoma (21.2%). Resection, surgical biopsy, or both were performed in 89.3% of cases. Complications were low, but included neurological worsening (2.2%) and infection (1.6%). Radiation therapy and chemotherapy were administered to 20.3% and 5.6% of patients, respectively. CONCLUSIONS Data from this study are suitable for benchmarking, describing prevailing patterns of care, and generating additional hypotheses for future studies.

Defining future directions in spinal cord tumor research: proceedings from the National Institutes of Health workshop

The relative rarity of spinal cord tumors has hampered the study of these uncommon nervous system malignancies. Consequently, the understanding of the fundamental biology and optimal treatment of spinal cord tumors is limited, and these cancers continue to inflict considerable morbidity and mortality in children and adults. As a first step to improving the outcome of patients affected with spinal cord tumors, the National Institutes of Health Office of Rare Diseases Research in cooperation with the National Cancer Institute and the National Institute of Neurological Disorders and Stroke convened a workshop to discuss the current status of research and clinical management of these tumors. The overall goal of this meeting was to initiate a process that would eventually translate fundamental basic science research into improved clinical care for this group of patients. Investigational priorities for each of these areas were established, and the opportunities for future multidisciplinary research collaborations were identified.

Descriptive epidemiology of central nervous system germ cell tumors: nonpineal analysis

Central nervous system (CNS) germ cell tumors (GCT) have not been epidemiologically well described. Our study describes 2 population-based series of nonpineal CNS GCT. Data on all primary (malignant and nonmalignant) CNS (ICD-O-3 sites: C70.0-C72.9, C75.1-C75.3) GCT diagnosed between 2000 and 2004 from the Central Brain Tumor Registry of the United States (CBTRUS) and on all malignant GCT diagnosed between 1992 and 2005 from the Surveillance, Epidemiology, and End Results (SEER) were analyzed. Of 234 nonpineal GCT in CBTRUS, the most common site was brain, NOS (31.6%). Males had a greater frequency (59.7%) than females (40.3%). However, by age group, the male-to-female incidence rate ratio (IRR) differed: children (0-14 years) had an IRR of 1.1, young adults (15-29 years) an IRR of 2.3, and adults (aged 30+) an IRR of 1.0. For children and young adults, most tumors were malignant (86.8% and 89.0%, respectively), whereas for adults, more than half were nonmalignant (56.8%). Germinoma was the most frequent diagnosis (61.5%). In SEER, the frequency of malignant GCT in the CNS (2.5%) was greater than that in the mediastinum (2.1%). Of 408 malignant CNS GCT, 216 (52.9%) were nonpineal. The male-to-female IRR was 1.5. Overall relative survival for nonpineal CNS malignant GCT was 85.3% at 2 years, 77.3% at 5 years, and 67.6% at 10 years. Previous studies of GCT that have not stratified by site have suggested greater gender disparity. Nonpineal CNS GCT show no significant gender preference, yet have outcomes similar to pineal GCT.

Subacute subdural hematoma in a 45-year-old woman with no significant past medical history after a roller coaster ride

Amusement park ride injuries have been newsworthy events for many years. The multitude and severity of these injuries has been reported many times over the past 20 years and includes spinal cord and vertebral injuries, subarachnoid hemorrhage, internal and vertebral artery dissections, and even a few cases of subdural hematoma (SDH). There has also been as many theories to explain these injuries as there have been injuries themselves including how G forces and rotational acceleration can cause both neuroparenchymal and neurovascular injury.

Malignant pineal germ-cell tumors: an analysis of cases from three tumor registries

The exact incidence of pineal germ-cell tumors is largely unknown. The tumors are rare, and the number of patients with these tumors, as reported in clinical series, has been limited. The goal of this study was to describe pineal germ-cell tumors in a large number of patients, using data from available brain tumor databases. Three different databases were used: Surveillance, Epidemiology, and End Results (SEER) database (1973-2001); Central Brain Tumor Registry of the United States (CBTRUS; 1997-2001); and National Cancer Data Base (NCDB; 1985-2003). Tumors were identified using the International Classification of Diseases for Oncology, third edition (ICD-O-3), site code C75.3, and categorized according to histology codes 9060-9085. Data were analyzed using SAS/STAT release 8.2, SEER*Stat version 5.2, and SPSS version 13.0 software. A total of 1,467 cases of malignant pineal germ-cell tumors were identified: 1,159 from NCDB, 196 from SEER, and 112 from CBTRUS. All three databases showed a male predominance for pineal germ-cell tumors (>90%), and >72% of patients were Caucasian. The peak number of cases occurred in the 10- to 14-year age group in the CBTRUS data and in the 15- to 19-year age group in the SEER and NCDB data, and declined significantly thereafter. The majority of tumors (73%-86%) were germinomas, and patients with germinomas had the highest survival rate (>79% at 5 years). Most patients were treated with surgical resection and radiation therapy or with radiation therapy alone. The number of patients included in this study exceeds that of any study published to date. The proportions of malignant pineal germ-cell tumors and intracranial germ-cell tumors are in range with previous studies. Survival rates for malignant pineal germ-cell tumors are lower than results from recent treatment trials for intracranial germ-cell tumors, and patients that received radiation therapy in the treatment plan either with surgery or alone survived the longest.

Expression of entry receptor nectin-1 of herpes simplex virus 1 and/or herpes simplex virus 2 in normal and neoplastic human nervous system tissues

Herpes simplex virus 1 and/or Herpes simplex virus 2 (HSV) are important pathogens of human nervous system (NS) and genetically modified HSV strains have been proposed as vectors for gene therapy targeting the brain and brain tumors. Nectin-1 is an immunoglobulin-like adhesion molecule that participates in the formation of synapses and serves as an entry receptor for HSV. The expression pattern of nectin-1 in normal human NS and brain tumors is not well understood. To better understand the nectin-1 expression in normal and neoplastic human NS, immunohistochemistry was used to detect the nectin-1 expression in sections of normal human brain, spinal cord and trigeminal and dorsal root ganglia (n=10) and in sections of primary NS neoplasms (n=22). In normal human NS, nectin-1 was detected in the soma and processes of central and peripheral neurons, in ependymal cells, choroid plexus epithelial cells, vascular endothelial cells and meningothelial cells. Oligodendrocytes, astrocytes, vascular smooth muscle cells, and Schwann cells showed variable immunoreactivity. Among tumors, schwannoma, fibrous meningioma, and medulloblastoma were nectin-1 negative. Oligodendroglioma, ependymoma, pilocytic astrocytoma, pleomorphic xanthoastrocytoma, diffuse astrocytoma, anaplastic astrocytoma, glioblastoma multiforme and meningothelial meningioma showed weak focal nectin-1-positivity. Ganglion cells of ganglioglioma were strongly positive. These studies provide novel information about the expression of nectin-1 in normal and neoplastic NS, and thus may lead to a better understanding of cell targeting by HSV during HSV-induced neurological disease and during a HSV-based gene therapy.

Animal models of leptomeningeal cancer

Animal models are a critical tool for our understanding of pathogenic mechanisms and the development of therapeutic strategies. Since the 1970's, numerous syngeneic and allogeneic rodent models of leptomeningeal cancer have been developed; in this chapter, we present representative models and discuss their clinical and translational implications.

Secondary Intracerebral Blastomycosis with Giant Yeast Forms

Secondary central nervous system (CNS) blastomycosis is an unusual manifestation of blastomycosis. We report a case of recurrent intracerebral blastomycosis that presented histopathologically with giant yeast-like cells and multinucleation that mimicked Coccidioides immitis. The yeast forms of Blastomyces dermatitidis usually range in size from 8 to 20 microm in diameter. Large or giant yeast forms (20-40 microm) are rare. The four cases previously reported in the literature involving giant yeast cell forms of B. dermatitidis are reviewed here. Intracerebral blastomycosis should be suspected in patients with signs and symptoms of CNS lesions and histories of primary blastomycosis, or treatment with corticosteroids, or comprised immune systems. The diagnosis should be confirmed by culture which presents typical biphasic microbiologic features.

Anatomy and physiology of the leptomeninges and CSF space

The arachnoid membrane and pia mater are the two membranous layers that comprise the leptomeninges. Cerebrospinal fluid is made within the ventricular system by cells of the choroid plexus and ependyma. This chapter describes in detail the normal anatomic structure and physiologic interactions of the cerebrospinal fluid and leptomeningeal space that are critical to our understanding and treatment of leptomeningeal metastases.

Leptomeningeal metastasis of primary central nervous system (CNS) neoplasms

Leptomeningeal dissemination of primary CNS tumors varies widely by histologic subtype. In certain tumors including medulloblastoma, ependymoma, germ cell tumors, and primary CNS lymphoma, seeding of the cerebrospinal fluid space is a critical factor in determining stage, prognosis and appropriate therapy. Other tumor types, such as glioma, may have radiographic evidence of leptomeningeal metastases without clear impact on prognosis or therapy.

Ciliary neurotrophic factor upregulates ubiquitin-proteasome components in a rat model of neuronal injury

Neuronal injury triggers the release of ciliary neurotrophic factor (CNTF), promoting local neuronal repair but producing systemic effects of anorexia and lean body weight loss. Due to the rapid rate of systemic protein loss stimulated by CNTF, we hypothesized involvement of the hepatic ubiquitin-proteasome proteolytic (UPP) pathway in CNTF-induced proteolysis. To assess the role of central CNTF in systemic UPP regulation, we measured hepatic UPP mRNA and proteasome activity in a rat model of neuronal injury and determined alterations induced by intracerebroventricular (ICV) administration of CNTF-neutralizing antibody or additional exogenous CNTF. We also assessed proteolytic parameters and nutritional status by measuring caloric intake, body weight, and protein levels. We produced neuronal injury by implanting a lateral ventricle cannula and giving daily ICV saline bolus injections, which increased hepatic 20S proteasome mRNA and enzymatic activity while reducing caloric intake, body weight, and protein levels compared to controls. Administration of ICV anti-CNTF antibodies (but not control antibodies) prevented these effects. Addition of exogenous CNTF augmented the weight loss along with the increases in 20S proteasome mRNA and proteolytic activity induced by neuronal injury. We conclude that CNTF decreases lean body weight through a combination of appetite inhibition and UPP pathway activation.

Oligodendroglioma and anaplastic oligodendroglioma:

BACKGROUND

Recent advances that have been made in diagnostic imaging, surgical technique, chemotherapy, molecular biology, and prediction of therapeutic response could have potential impact on the optimal diagnosis and treatment of patients with brain tumors, especially those with oligodendrogliomas. In this article, the topic of oligodendroglioma and anaplastic oligodendroglioma is reviewed, highlighting the new clinical developments.

METHODS

Information for this review was obtained by performing a Medline search for recent references using the term "oligodendroglioma." The bibliographies of papers obtained also were checked for articles that could provide additional understanding of this disease and its current treatment.

RESULTS

The incidence of oligodendroglioma is increasing, most likely due to its improved recognition. Seizures and/or headaches are still common presenting features, and surgery continues to be the primary treatment. Positron emission tomography (PET) and molecular analysis of the surgical specimen are emerging as important diagnostic tools. Patients having either oligodendroglioma or anaplastic oligodendroglioma are likely to respond to chemotherapy. This has had an impact upon the timing of radiation therapy. Survival times are increasing, and patients can now be divided into prognostic subgroups based on the molecular features of their tumors. While procarbazine-CCNU-vincristine (PCV) chemotherapy has been the standard, other agents, notably temozolomide, are currently being tested.

CONCLUSIONS

The algorithm for diagnosing and treating patients with oligodendrogliomas has changed. Neurosurgeons need to be aware of the new developments so they can offer sound advice to their patients.

Simplified Surgical Placement and Stabilization Methods for Intracerebroventricular Cannulas in Rat Lateral Ventricles

Intracerebroventricular cannulation in rat models is an efficient tool for exploring the effects of substances directly injected into the CNS, bypassing the blood-brain barrier. Techniques for surgically securing the ICV cannula require a balance between ease of application and adequate stability. The authors tested several methods of lateral ventricle cannula stabilization, especially focusing on a comparison of cyanoacrylate gel to cranioplastic cement with an anchoring bone screw.

Current management of intraventricular hemorrhage

BACKGROUND

Intraventricular hemorrhage (IVH) continues to present a challenge to neurosurgeons, often being accompanied by significant morbidity and mortality. The purpose of this paper is to present a review of the recent literature concerning the treatment of patients with IVH, and describe our current management scheme for this disorder.

METHODS

A literature search was conducted to identify key articles pertaining to the pathophysiology and treatment of IVH, focusing on the more recent articles. The bibliographies of selected papers were also screened for additional useful publications.

RESULTS

Management of IVH is primarily directed at controlling intracranial pressure through an external ventricular drain (EVD), but this catheter often becomes occluded by coagulated blood. The fibrinolytic system of the cerebrospinal fluid is limited, and blood may remain in the ventricles for months after a hemorrhage. IVH has a poor prognosis, partly because of the continuing mass effect of blood clots on the ventricular walls. Therefore, investigators have administered fibrinolytic agents directly into the ventricles of patients with IVH. Clinical studies of fibrinolytic therapy for IVH have found a 30 to 35% reduction in mortality with treatment, but have not yet clearly documented an improved neurologic outcome for the survivors.

CONCLUSIONS

Fibrinolytic therapy may be life saving in severe cases of IVH. While many issues need to be resolved, our current practice is to administer intraventricular tissue plasminogen activator (t-PA or alteplase) if hemorrhage involves > or =30% of the volume of one of the lateral ventricles and/or the 3(rd) or 4(th) ventricle. We currently give t-PA after ruling out or treating a possible source of further bleeding, such as an unsecured aneurysm.

Genomic expression discovery predicts pathways and opposing functions behind phenotypes

Discovering states of genetic expression that are true to a high degree of certainty is likely to predict gene function behind biological phenotypes. The states of expression (up- or down-regulated) of 19200 cDNAs in 10 meningiomas are compared with normal brain by an algorithm that detects only 1 false measurement per 192000; 364 genes are discovered. The expression data accurately predict activation of signaling pathways and link gene function to specific phenotypes. Meningiomas appear to acquire aberrant phenotypes by disturbing the balanced expression of molecules that promote opposing functions. The findings expose interconnected genes and propose a role of genomic expression discovery in functional genomics of living systems.

Mathematical modeling of noise and discovery of genetic expression classes in gliomas

The microarray array experimental system generates noisy data that require validation by other experimental methods for measuring gene expression. Here we present an algebraic modeling of noise that extracts expression measurements true to a high degree of confidence. This work profiles the expression of 19 200 cDNAs in 35 human gliomas; the experiments are designed to generate four replicate spots/gene with switching of probes. The validity of the extracted measurements is confirmed by: (1) cluster analysis that generates a molecular classification differentiating glioblastoma from lower-grade tumors and radiation necrosis; (2) By what other investigators have reported in gliomas using paradigms for assaying molecular expression other than gene profiling; and (3) Real-time RT-PCR. The results yield a genetic analysis of gliomas and identify classes of genetic expression that link novel genes to the biology of gliomas.

Intracranial ependymoma

OBJECT

An intracranial ependymoma is a relatively rare but very interesting variety of glioma. In this paper, the authors compiled a review of the pathological features, imaging characteristics, and treatment strategies related to this brain tumor.

METHODS

A Medline search was conducted using the term "ependymoma." The bibliographies of papers obtained were also checked for articles and chapters that could provide additional understanding of this tumor. Malignant ependymomas and ependymomas of the spinal cord (including myxopapillary ependymomas) were excluded from this review.

CONCLUSIONS

The posterior fossa is the most frequent site for an intracranial ependymoma. Children are frequently affected. Most authors recommend resecting as much of the tumor as is safely possible. Microscopically, ependymal tumors show both epithelial and glial features. Glial fibrillary acidic protein immunohistochemistry, therefore, helps in identifying ependymomas. Because ependymomas often recur despite surgical intervention, radiotherapy and/or radiosurgery may also play an important role in their treatment. The use of chemotherapy in the treatment of these tumors, especially in the very young, is still being studied.

Oligodendroglioma: pathology and molecular biology

BACKGROUND

Recently, important new information has become available concerning the histologic recognition and molecular biology of oligodendrogliomas. This information, in turn, impacts the way neurosurgeons diagnose and treat patients with these tumors. The purpose of this paper is to review the pathology and basic science of oligodendroglioma, highlighting these developments.

METHODS

Information for this review was obtained by a Medline search using the term "oligodendroglioma," and limiting the results to articles dealing with pathology. Chapters from standard textbooks were also used, and bibliographies were checked for additional key articles contributing to the understanding of the pathobiology of this disease.

RESULTS

On histologic examination, oligodendrogliomas must be differentiated from tumors including the fibrillary astrocytoma, clear cell ependymoma, central neurocytoma, and dysembryoplastic neuroepithelial tumor (DNT). There is no specific immunocytochemical marker allowing for the recognition of human oligodendroglial tumor cells. A current simplified grading scheme separates these tumors into low grade (WHO grade II) and anaplastic (WHO grade III) oligodendrogliomas. New molecular and genetic markers may aid in grading oligodendrogliomas and identifying patients with a better prognosis or response to chemotherapy. Markers studied include Ki-67, PCNA, EGFr, VEGF, platelet-derived growth factor, p16, p18, p53, bcl-2, COX-1, and chromosomal deletions. The combination of allelic losses on chromosomes 1p and 19q has been statistically associated with a longer recurrence-free survival after chemotherapy.

CONCLUSIONS

A patient with an oligodendroglioma may at times still present a diagnostic challenge for the neuropathologist. Yet making an accurate diagnosis is essential, since the clinical course and optimal therapeutic approach differs from that of other gliomas. In the near future, molecular characterization of oligodendrogliomas is expected to play an even greater clinical role.

Fibrinolytic therapy in intraventricular hemorrhage

OBJECTIVE

To review the literature concerning intraventricular administration of fibrinolytic agents to treat patients with intraventricular hemorrhage (IVH).

DATA SOURCES

An extensive literature search (MEDLINE, EMBASE, Conference Proceedings) was conducted to identify articles in English published between 1966 and May 2000 pertaining to the pathophysiology of IVH and its treatment by intraventricular administration of recombinant tissue plasminogen activator (alteplase) or urokinase (u-PA). The bibliographies of selected identified articles were also screened for publications not found in the computerized search.

STUDY SELECTION

All pertinent publications were reviewed and considered. Those describing the intraventricular administration of fibrinolytic agents to patients with IVH were included.

DATA SYNTHESIS

IVH has a poor prognosis, partly due to the mass effect of blood clots on the ventricular walls. The cerebrospinal fluid has a limited fibrinolytic system. Therefore, clots may remain in the ventricles for months after a hemorrhage. The management of IVH is primarily directed at controlling intracranial pressure through an external ventricular drain, but this catheter often becomes occluded by coagulated blood. To overcome this problem, and to dissolve the residual blood clot, investigators have administered alteplase or u-PA directly into the ventricles of patients with IVH. Complications of this therapy include infection and possible rebleeding. Clinical studies of fibrinolytic therapy for IVH have found a 30-35% reduction in mortality with treatment, but to date, have not clearly documented improved neurologic outcome of the survivors.

CONCLUSIONS

Fibrinolytic therapy with alteplase or u-PA may be life-saving in severe cases of IVH. Yet many technical issues remain to be resolved, such as the optimal dose, frequency, method, timing, and duration of administration of the agent. Additional randomized, double-blind, placebo-controlled studies need to be performed so that the true value of this therapy can be assessed.

Current diagnosis and treatment of oligodendroglioma

Object

The strategies used to diagnose and treat oligodendroglial tumors have changed significantly over the past decade. The purpose of this paper is to review the topic of oligodendroglioma, emphasizing the new developments.

Methods

Information was obtained by conducting a Medline search in which the term oligodendroglioma was used. Recent editions of standard textbooks were also studied.

Because of tools such as magnetic resonance imaging, oligodendrogliomas are being diagnosed earlier, and they are being recognized more frequently histologically than in the past. Seizures are common in these patients. Functional mapping and image-guided surgery may now allow for a safer and more complete resection, especially when tumors are located in difficult areas. Genetic analysis and positron emission tomography may provide data that supplement the standard diagnostic tools. Unlike other low-grade gliomas, patients in whom residual or recurrent oligodendroglioma (World Health Organization Grade II) is present may respond to chemotherapy. Although postoperative radiotherapy prolongs survival of the patient, increasingly this therapeutic modality is being delayed until tumor recurrence, especially if a gross-total tumor resection has been achieved. Oligodendrogliomas are the first type of brain tumor for which “molecular” characterization gives important information. The most significant finding is that allelic losses on chromosomes 1p and 19q indicate a favorable response to chemotherapy.

Conclusions

Whereas surgery continues to be the primary treatment for oligodendroglioma, the scheme for postoperative therapy has shifted, primarily because of the lesion's relative chemosensitivity. Molecular characterization of oligodendrogliomas may become a standard practice in the near future.

Fibrinolytic therapy in intraventricular hemorrhage

OBJECTIVE

To review the literature concerning intraventricular administration of fibrinolytic agents to treat patients with intraventricular hemorrhage (IVH).

DATA SOURCES

An extensive literature search (MEDLINE, EMBASE, Conference Proceedings) was conducted to identify articles in English published between 1966 and May 2000 pertaining to the pathophysiology of IVH and its treatment by intraventricular administration of recombinant tissue plasminogen activator (alteplase) or urokinase (u-PA). The bibliographies of selected identified articles were also screened for publications not found in the computerized search.

STUDY SELECTION

All pertinent publications were reviewed and considered. Those describing the intraventricular administration of fibrinolytic agents to patients with IVH were included.

DATA SYNTHESIS

IVH has a poor prognosis, partly due to the mass effect of blood clots on the ventricular walls. The cerebrospinal fluid has a limited fibrinolytic system. Therefore, clots may remain in the ventricles for months after a hemorrhage. The management of IVH is primarily directed at controlling intracranial pressure through an external ventricular drain, but this catheter often becomes occluded by coagulated blood. To overcome this problem, and to dissolve the residual blood clot, investigators have administered alteplase or u-PA directly into the ventricles of patients with IVH. Complications of this therapy include infection and possible rebleeding. Clinical studies of fibrinolytic therapy for IVH have found a 30-35% reduction in mortality with treatment, but to date, have not clearly documented improved neurologic outcome of the survivors.

CONCLUSIONS

Fibrinolytic therapy with alteplase or u-PA may be life-saving in severe cases of IVH. Yet many technical issues remain to be resolved, such as the optimal dose, frequency, method, timing, and duration of administration of the agent. Additional randomized, double-blind, placebo-controlled studies need to be performed so that the true value of this therapy can be assessed.

Therapeutic effects of sodium butyrate on glioma cells in vitro and in the rat C6 glioma model

OBJECTIVE

Preliminary in vitro studies have indicated that sodium butyrate inhibits the proliferation of cultured glioma cells and induces cellular differentiation, making it potentially useful as a therapeutic agent for patients with glioblastoma multiforme. The purpose of this study was to expand on the preliminary research by investigating the effects of sodium butyrate on multiple cell lines, explanted cells from glioblastoma tumor specimens, and in vivo in the rat C6 glioma brain tumor model.

METHODS

Four malignant glioma cell lines (A-172, T98G, U118MG, and C6) and two primary cell cultures derived from human glioblastoma tumor specimens were treated with 2 mmol/L sodium butyrate for up to 72 hours. Sodium butyrate-induced effects on cell morphology, proliferation, cell cycle distribution, migration, glial fibrillary acidic protein staining, and S100beta protein content were determined. For in vivo studies, a total of 64 male Wistar-Furth rats underwent operations to implant C6 glioma cells stereotactically or were used as controls. The rats were treated with escalating doses of sodium butyrate by microinfusion with Alzet minipumps (Durect Corp., Cupertino, CA).

RESULTS

Sodium butyrate treatment in vitro produced changes in morphology and glial fibrillary acidic protein expression indicative of cellular differentiation. In cell lines and explanted cells, sodium butyrate consistently inhibited glioblastoma cell proliferation (to 51 +/- 6% that of controls) and migration (to 46 +/- 17%). Intratumoral infusion of 40 mmol/L sodium butyrate prolonged the survival of Wistar-Furth rats with intracerebral C6 tumors (P = 0.013) without detectable toxicity.

CONCLUSION

These data support further consideration of direct interstitial infusion of sodium butyrate in a Phase I clinical study for patients with recurrent glioblastoma multiforme.

Progress in the diagnosis and treatment of patients with meningiomas. Part I: diagnostic imaging, preoperative embolization

BACKGROUND

The clinical management of patients with meningiomas has changed over the past decade. Change has occurred because of a variety of factors including improved diagnostic imaging, better results with surgery and interventional neuroradiology, and the advent of radiosurgery. Recent clinical studies from several disciplines have provided new information on topics germane to the management of patients with meningiomas. Collecting this information into a series of review articles would have significant value, primarily for neurosurgeons.

OBJECTIVE

The purpose of this first paper is to bring together and evaluate the available data on: 1) noninvasive diagnostic imaging of meningiomas, including magnetic resonance imaging (MRI), computed tomography (CT) scanning, and MR angiography, venography and spectroscopy; 2) the present role of cerebral angiography in patients with meningiomas; and 3) the current status of preoperative embolization for these tumors.

RESULTS

With the advent of MR technology, the quality of diagnostic imaging for meningiomas has improved dramatically, and this is reflected in more sophisticated preoperative planning. MR imaging provides improved delineation of dura and sinus involvement, and even information about a tumor's consistency. Meningiomas have characteristic neuroimaging features, yet other lesions can still mimic a meningioma. MR venography can be used to demonstrate sinus patency, but intra-arterial cerebral angiography gives the most precise information concerning the degree of tumor involvement of critical vascular structures, and the anatomy of arterial feeders. In trained hands, superselective catheterization for preoperative embolization of meningiomas is feasible, and seems to be reasonably safe.

CONCLUSIONS

MR imaging, CT scans, and cerebral angiography can currently be used in a complementary fashion to diagnose, evaluate, and treat patients with meningiomas, with a high degree of clinical certainty. Angiography is used to determine the sites of blood supply to the tumor, which can then be attacked first intraoperatively, making tumor removal easier. Preoperative embolization continues to have value in selected patients, including those in whom the blood supply to the tumor is difficult to access at the time of surgery.