Alterations in cerebrospinal fluid proteins in a presymptomatic primary glioma model

Background

Understanding the early relationship between brain tumor cells and their environment could lead to more sensitive biomarkers and new therapeutic strategies. We have been using a rodent model of neurocarcinogenesis in which all animals develop brain tumors by six months of age to establish two early landmarks in glioma development: the appearance of a nestin⁺ cell at thirty days of age and the appearance of cellular hyperplasia between 60 and 120 days of age. We now report an assessment of the CSF proteome to determine the changes in protein composition that occur during this period.

Materials and Methods

Nestin⁺ cell clusters and microtumors were assessed in 63 ethylnitrosourea-exposed rats on 30, 60, and 90 days of age. CSF was obtained from the cisterna magna from 101 exposed and control rats at 30, 60, and 90 days and then analyzed using mass spectrometry. Differentially expressed peaks were isolated and identified.

Results

Nestin⁺ cells were noted in all ethylnitrosourea-exposed rats assessed pathologically. Small microtumors were noted in 0%, 18%, and 67% of 30-, 60-, and 90-day old rats, respectively (p<0.05, Chi square). False Discovery Rate analysis of peak intensities showed that the number of true discoveries with p<0.05 increased markedly with increasing age. Isolation and identification of highly differentially detected proteins at 90 days of age revealed increases in albumin and a fragment of α1 macroglobulin and alterations in glutathionylated transthyretin.

Conclusions

The presence of increased albumin, fragments of cerebrospinal fluid proteins, and glutathione breakdown in temporal association with the development of cellular hyperplasia, suggests that, similar to many other systemic cancers, inflammation and oxidative stress is playing an important early role in the host’s response to brain tumor development and may be involved in affecting the early growth of brain tumor.

Metabolite kinetics in C6 rat glioma model using magnetic resonance spectroscopic imaging of hyperpolarized [1-(13)C]pyruvate

In addition to an increased lactate-to-pyruvate ratio, altered metabolism of a malignant glioma can be further characterized by its kinetics. Spatially resolved dynamic data of pyruvate and lactate from C6-implanted female Sprague-Dawley rat brain were acquired using a spiral chemical shift imaging sequence after a bolus injection of a hyperpolarized [1-(13)C]pyruvate. Apparent rate constants for the conversion of pyruvate to lactate in three different regions (glioma, normal appearing brain, and vasculature) were estimated based on a two-site exchange model. The apparent conversion rate constant was 0.018 ± 0.004 s(-1) (mean ± standard deviation, n = 6) for glioma, 0.009 ± 0.003 s(-1) for normal brain, and 0.005 ± 0.001 s(-1) for vasculature, whereas the lactate-to-pyruvate ratio, the metabolic marker used to date to identify tumor regions, was 0.36 ± 0.07 (mean ± SD), 0.24 ± 0.07, and 0.12 ± 0.02 for glioma, normal brain, and vasculature, respectively. The data suggest that the apparent conversion rate better differentiate glioma from normal brain (P = 0.001, n = 6) than the lactate-to-pyruvate ratio (P = 0.02).

5'-AMP-activated protein kinase activity is elevated early during primary brain tumor development in the rat

We found that adenosine 5'-monophosphate-activated protein kinase (AMPK), which is considered the "fuel sensor" of mammalian cells because it directly responds to the depletion of the fuel molecule ATP, is strongly activated by tumor-like hypoxia and glucose deprivation. We also observed abundant AMPK activity in tumor cells in vivo, using subcutaneous tumor xenografts prepared from cells transformed with oncogenic H-Ras. Such rapidly growing transplants of tumor cells, however, represent fully developed tumors that naturally contain energetically stressed microenvironments that can activate AMPK. Therefore, to investigate the induction of AMPK activity during experimental tumorigenesis, we used an established model of brain tumor (glioma) development in the offspring of rats exposed prenatally to the mutagen N-ethyl-N-nitrosourea. We observed that immunostaining for a specific readout of AMPK activity (AMPK-dependent phosphorylation of acetyl-CoA carboxylase) was prominent during N-ethyl-N-nitrosourea-initiated neurocarcinogenesis, from the occurrence of early hyperplasia (microtumors) to the emergence of large gliomas. Moreover, we observed that immunostaining for activating phosphorylation of AMPK correlated with the same stages of glioma development, notably in mitotic tumor cells in which the signal showed punctate as well as cytoplasmic patterns associated with spindle formation. Based on these observations, we propose that neurocarcinogenesis requires AMPK-dependent regulation of cellular energy metabolism.

Gender disparity in the rate of partner abandonment in patients with serious medical illness

BACKGROUND

Life-threatening illness creates severe stress that may result in marital discord, separation, or divorce and may adversely impact treatment, quality of life, and survival. The few studies that are available to date have suggested that the risk of divorce is not higher in cancer patients, but to the authors' knowledge, no data exist to date that have examined the effect of gender on this rate.

METHODS

A total of 515 patients were prospectively identified as having either a malignant primary brain tumor (N = 214), a solid tumor with no nervous system involvement (N = 193), or multiple sclerosis (N = 108) who were married at the time of diagnosis. Basic demographic information and data regarding marital status were compiled. Patients were followed prospectively from enrollment until death or study termination.

RESULTS

Women composed 53% of the patient population. Divorce or separation occurred at a rate similar to that reported in the literature (11.6%). There was, however, a greater than 6-fold increase in risk after diagnosis when the affected spouse was the woman (20.8% vs 2.9%; P < .001). Female gender was found to be the strongest predictor of separation or divorce in each cohort. Marriage duration at the time of illness was also correlated with separation among brain tumor patients (P = .0001). Patients with brain tumors who were divorced or separated were more likely to be hospitalized, and less likely to participate in a clinical trial, receive multiple treatment regimens, complete cranial irradiation, or die at home (P < .0001).

CONCLUSIONS

Female gender was found to be a strong predictor of partner abandonment in patients with serious medical illness. When divorce or separation occurred, quality of care and quality of life were adversely affected.

Understanding the origins of gliomas and developing novel therapies: cerebrospinal fluid and subventricular zone interplay

Glioblastoma multiforme (GBM), the most common malignant primary brain tumor in adults, carries a poor prognosis, with median survival generally less than 1 year. Although initial therapy often eradicates the bulk of the tumor, disease recurrence, usually within 2 cm of the original tumor, is almost inevitable. This may be due to a failure of current therapies to eradicate viable chemotherapy- and radiotherapy-resistant neoplastic progenitor cells, which may then repopulate tumors. An increasing body of preclinical data suggests that these cells may correspond to stem cells derived from the subventricular zone (SVZ), which migrate to tumor sites and contribute to glioma growth and recurrence. Therapeutic targeting of SVZ stem cell populations via cerebrospinal fluid (CSF)-directed therapy may provide a means for limiting tumor recurrence. This approach has proved successful in the treatment of medulloblastoma, another brain tumor thought to be derived from stem cells. We discuss the rationale and design considerations for a clinical trial to evaluate the efficacy of CSF-directed therapy for preventing GBM recurrence.

A randomized, double-blind study comparing corticorelin acetate with dexamethasone in patients with primary malignant glioma who require increased dexamethasone doses to control symptoms of peritumoral brain edema

2080

Background: Corticorelin acetate (CrA) is a synthetic peptide of corticotropin-releasing factor, undergoing clinical trials as a treatment for peritumoral edema in patients with cerebral tumors. This study compared CrA therapy vs an increase in dexamethasone (dex) dose (+4 mg) for controlling symptoms in primary glioma patients with a subacute exacerbation. Methods: In addition to their prestudy dex dose, patients were randomized to receive CrA 1 mg bid SC or control (+4 mg dex PO) for 8 weeks. Patients were evaluated at baseline and during weeks 1 and 2 for their neurologic status, Karnofsky Performance Score (KPS), and continuing dex requirements. The primary endpoint was response, defined as no post-baseline increase in dex dose >4 mg for >1 day; stable or improved KPS; and ≥25% improvement in 10-item Neurological Examination Score during weeks 1 and 2. Dex therapy requirements were also evaluated. The study aimed to enroll 120 patients, but was terminated with only 37 patients (20 CrA, 17 control) due to slow recruitment. Results: Formal statistical analyses were not undertaken due to the small sample size. The treatment groups had similar demographic and baseline disease characteristics. Despite the small numbers, the data suggest that CrA treatment had similar efficacy to increased dex: (1) The proportions of responders were similar (CrA 3/20; control 3/17); (2) Comparable proportions of patients completed 8 weeks’ treatment (CrA 16/20; control 12/17); (3) After randomization of blinded study drug (CrA or dex 4 mg), dex dosing remained stable for most patients in each arm (CrA 12/20; control 11/17); (4) The mean daily dex dose was 3 mg in the CrA arm and 7 mg in the control arm. There was a lower incidence of cushingoid symptoms in the CrA arm (CrA 1/20, control 3/17). Patients in the CrA arm reported more injection site erythema and flushing vs. the control arm. CrA was well tolerated and no patient withdrew from the trial because of CrA side effects. Conclusions: CrA may be of value in managing patients with cerebral tumors who have subacute exacerbations of their symptoms, without needing to increase their dex dose.

[Table: see text]

A long-term open-label extension study examining the steroid-sparing effects of corticorelin acetate in patients with cerebral tumors

2079

Background: Corticorelin acetate (CrA) is a synthetic peptide formulation of corticotropin-releasing factor, which is undergoing clinical trials as a treatment for peritumoral edema. The objective of this study was to evaluate long-term safety, tolerability and steroid-sparing potential of CrA in patients with primary or secondary brain tumors and peritumoral edema. Methods: Patients from two randomized double-blind controlled studies who received either CrA (CrA-CrA group) or placebo (PLA) (PLA-CrA group) were permitted to receive open-label CrA 1 mg SC bid after participation in the initial studies. Treating physicians were requested to attempt and maintain the maximum possible reduction of the dexamethasone (dex) dose without knowledge of their patients’ prior treatment regimen in the controlled feeder studies. During this extension study, patients’ dex doses and adverse events were monitored monthly; neurologic function and clinical status were recorded 3 monthly. For this analysis, data up to October 17, 2008, are reported from this ongoing study. Results: Of the 110 patients enrolled, 47 (43%) reduced their dex dose to zero and 67 (61%) were able to reduce their dose to ≤1 mg/day. At entry to this extension study, the daily baseline dex dose was lower for patients who had previously received CrA (3.9 mg; n = 59) than for those who had previously received PLA (6.2 mg; n = 51). The PLA-CrA group showed a greater percent decrease in dex dose than the CrA-CrA group at Week 4 (24.0% vs. 12.6%). At week 8 the mean prescribed dex dose was similar in the two groups (PLA-CrA 3.7 mg vs. CrA-CrA 3.4 mg). Long-term treatment with CrA has been well tolerated with no reported safety concerns. To date, 48 patients remained on study for ≥6 months, 27 patients for ≥12 months, 5 patients for >2 years; 31 patients remain on study. Conclusions: These findings indicate that CrA is safe and well-tolerated, and may enable substantial reduction or cessation of dex therapy for many patients with cerebral tumors.

[Table: see text]

A distinct phenotypic change in gliomas at the time of magnetic resonance imaging detection

Object

Although gliomas remain refractory to treatment, it is not clear whether this characteristic is fixed at the time of its origin or develops later. The authors have been using a model of neurocarcinogenesis to determine whether a time exists during a glioma's evolution during which it is detectable but still curable, thus providing a justification for exploring the clinical merits of an early detection and treatment strategy. The authors recently reported the presence of 2 distinct cellular subsets, 1 expressing nestin and the other both glial fibrillary acidic protein (GFAP) and osteopontin (OPN), within all examined gliomas that developed after in utero exposure to ethylnitrosourea.

Methods

In this study, the authors used magnetic resonance (MR) imaging to assess when these 2 subpopulations appeared during glioma evolution.

Results

Using T2-weighted and diffusion-weighted MR imaging, the authors observed that gliomas grew exponentially once detected at rates that were location-dependent. Despite large differences in growth rates, however, they determined by correlating histochemistry with imaging in a second series of animals, that all lesions initially detected on T2-weighted images contained both subsets of cells. In contrast, lesions containing only nestin-positive cells, which appeared on average 40 days before detection on MR images, were not detected.

Conclusions

The sequential appearance of first the nestin-positive cells followed several weeks later by those expressing GFAP/OPN suggests that all gliomas arise through common early steps in this model. Furthermore, the authors hypothesize that the expression of OPN, a molecule associated with cancer aggressiveness, at the time of T2-weighted detection signals a time during glioma development when the lesion becomes refractory to treatment.

The effect of corticorelin acetate on peritumoral brain edema: An interim report of an open-label study as part of a phase III program

9095

Background: Steroid treatment of peritumoral brain edema (PBE) in patients with malignant brain tumors (BTs) is frequently associated with debilitating steroid side effects. The investigational agent corticorelin acetate injection, a synthetic peptide identical to h-corticotropin-releasing factor (hCRF), compared favorably to dexamethasone in reducing PBE in animal models of primary or metastatic BT. Toxicology and clinical studies including a pilot study in patients with malignant BTs published in ASCO's Annual Meeting Proceedings, showed hCRF to be safe and virtually devoid of steroid side effects. Methods: Following completion of follow-up periods for one of 2 randomized, double-blind phase III trials comparing corticorelin acetate to placebo or dexamethasone, patients with primary or metastatic BTs, PBE on pre-randomized study MRIs, and Karnofsky Performance Scores =50 were enrolled in an open-label extension study in which they took 1.0 mg corticorelin acetate by subcutaneous injection bid. We tapered dexamethasone maximally as tolerated. Patients were assessed every 4 weeks. Results: Of 47 patients who received open-label corticorelin acetate for up to one year, 28 patients continue to take it. Corticorelin acetate was safe and well tolerated, with no related deaths or SAEs. Patients typically refractory to reducing steroids - including at least 5 patients >55 years of age, 7 patients with recurrent brain tumor, and 11 patients in whom prior attempt(s) to reduce dexamethasone had been unsuccessful – reduced dexamethasone with improvement or resolution of steroid side effects. We will present data in the first 30 patients to take corticorelin acetate for at least 12 weeks [the largest and longest-treated group reported to date] including changes in steroid side effects correlated with net cumulative changes in dexamethasone, and treatment-emergent AEs. Conclusions: This interim analysis supports corticorelin acetate's long-term safety, tolerability, and steroid-sparing potential. The outcome of the ongoing randomized trials may determine whether this innovative agent leads to fundamental changes in the management of PBE in patients with primary or metastatic BTs.

[Table: see text]

Osteopontin expression in intratumoral astrocytes marks tumor progression in gliomas induced by prenatal exposure to N-ethyl-N-nitrosourea

To better study early events in glioma genesis, markers that reliably denote landmarks in glioma development are needed. In the present study, we used microarray analysis to compare the gene expression patterns of magnetic resonance imaging (MRI)-localized N-ethyl-N-nitrosourea (ENU)-induced tumors in rat brains with those of uninvolved contralateral side and normal brains. Our analysis identified osteopontin (OPN) as the most up-regulated gene in glioma. Using immunohistochemistry we then confirmed OPN expression in every tumor examined (n = 17), including those with diameters as small as 300 mum. By contrast, no OPN immunostaining was seen in normal brain or in brains removed from ENU-exposed rats before the development of glioma. Further studies confirmed that OPN was co-localized exclusively in intratumoral glial fibrillary acidic protein-expressing cells and was notably absent from nestin-expressing ones. In conjunction with this, we confirmed that both normal neurosphere cells and ENU-im-mortalized subventricular zone/striatal cells produced negligible amounts of OPN compared to the established rat glioma cell line C6. Furthermore, inducing OPN expression in an immortalized cell line increased cell proliferation. Based on these findings, we conclude that OPN overexpression in ENU-induced gliomas occurs within a specific subset of intratumoral glial fibrillary acidic protein-positive cells and becomes evident at the stage of tumor progression.

Optimizing therapy for patients with brain metastases

Brain metastases from systemic cancers are the most common malignant brain tumors encountered. Although prognosis remains poor, it is possible to stratify patients according to risk. Furthermore, an aggressive therapeutic approach for good-risk patients that includes a combination of either surgery or stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) can improve survival and decrease the risk of central nervous system progression.

Motexafin gadolinium (MGd) combined with prompt whole brain radiation therapy (RT) prolongs time to neurologic progression in non-small cell lung cancer (NSCLC) patients with brain metastases: Results of a phase III trial

7014

Background: In a previous randomized study, RT plus MGd prolonged time to neurologic progression (TNP) in NSCLC patients (pts) with brain metastases (BM) (p=0.048). Methods: This Phase 3 trial randomized pts with BM from NSCLC and KPS ≥70 to RT (30 Gy) or RT+MGd, 5 mg/kg qd x 10. A sample size of 550 was based on α=0.001, β=0.8, hazard ratio (HR)=0.65, with a primary endpoint of TNP determined by a blinded events review committee. Results: 554 pts received RT (N=275) or RT+MGd (N=279), 348 in North America (NA), 206 in Europe and Australia (EA). Treatment arms were balanced for factors of known prognostic importance. Most pts had multiple BM (81%), extracranial metastases (51%) and presented with neurologic deficits (84%). Treatment with MGd was well tolerated, with >92% of intended doses administered. Most common MGd-related grade 3+ adverse events were hypertension (4%), ALT increase (3%), and fatigue (3%). TNP improved from 10 months (mo) for RT to 15.4 mo for RT+MGd, p=0.12, HR=0.78. Time to neurocognitive progression was also improved, p=0.089, HR=0.79. More RT pts required salvage brain surgery or radiosurgery than RT+MGd pts (41 RT, 19 RT+MGd). In NA pts, statistically significant prolongation of both TNP, from 8.8 mo for RT to 24.2 mo for RT+MGd, p=0.004, HR=0.53, and time to neurocognitive progression, p=0.04, HR=0.69, were observed. In NA, RT was started sooner after the diagnosis of BM than in EA (median/mean 1.6/2.2 weeks NA vs. 3.0/6.5 weeks EA). There was a significant interaction between earlier RT and MGd benefit, p=0.017. When RT was initiated within 3 weeks of BM diagnosis, regardless of region, TNP was significantly prolonged by addition of MGd (N=378, p=0.006, HR=0.59). When initiation of RT was delayed beyond 3 weeks after BM diagnosis (N=176, 21% of NA pts, 50% of EA pts), MGd benefit was lost. A major reason for RT delay was use of chemotherapy as initial treatment for BM in 41 pts, 17% NA, 83% EA. Conclusions: MGd significantly prolonged TNP in NSCLC patients with BM receiving prompt RT in this randomized Phase 3 trial. The majority of patients in NA received prompt RT (79%), leading to a statistically and clinically significant benefit when combined with MGd.

[Table: see text]

Prevention and treatment of central nervous system involvement by non-Hodgkin's lymphoma: a review of the literature

Direct invasion of the central nervous system (CNS) occurs in 5% of all patients with non-Hodgkin's lymphoma, either at the time of presentation, as a solitary site of relapse, or during the course of progressive disease. Over the last several years, several studies, mostly retrospective, have analyzed risk factors associated with this complication as well as various methods to both treat and prevent it. A systematic review of the literature reveals that although a profile of a patient at particularly high risk for developing disease can be identified, treatments are for the most part ineffective at improving survival in patients with CNS lymphoma, and there is no high-quality evidence that prophylaxis prevents its occurrence. A randomized controlled trial to assess the value of prophylaxis in this disease is warranted, and suggestions for how such a trial might be designed are included in this review.

Neurologic complications of hematologic neoplasms

The new WHO classification of hematopoietic and lymphatic neoplasms was devised to offer pathologists, oncologists, and geneticists a system of classification based on histopathologic, clinical, and genetic features. From the neurologic standpoint, it offers an opportunity to consolidate the complications produced by leukemias, lymphomas, and plasma cell dyscrasias. This article summarizes such complications that occur as a result of direct infiltration or compression of nervous tissue by tumor or as a result of indirect effects such as infection, vascular disorders, iatrogenesis, and paraneoplasia.

Neural stem cells and neuro-oncology: quo vadis?

Conventionally, gliomas are assumed to arise via transformation of an intraparenchymal glial cell that forms a mass that then expands centrifugally, eventually invading surrounding tissues. We propose an alternative model in which gliomas arise via initiation and promotion of cells within the brain's subependymal layer or subventricular zone, the source of a recently characterized pool of neural cells with the properties of self-renewal and multipotentiality (i.e., stem cells) that persists into adulthood. In this model, the particular histological subtype of glioma would represent the effects of temporal and spatial environmental influences rather than the particular cell of origin and the disease's centrifugal point would be the subependymal layer. The implications of such a model are discussed.

Somatic plasticity of neural stem cells: fact or fancy?

Several studies have described the potential for embryonic and adult neural stem cells to differentiate into non-neural cells such as muscle and blood, tissues that are derived from non-neuroectodermal germ layers. This raised the exciting possibility that these cells possessed a broader range of differentiation potential than originally thought and raised interesting prospects for possible transplantation utilization. However, a number of recent reports have raised questions about whether the phenomena observed actually represented true somatic plasticity. In this review, we critically analyze these studies with the aim of providing some criteria by which future studies that address this important problem may be evaluated.

Quantitative measurement of quality outcome in malignant glioma patients using an independent living score (ILS). Assessment of a retrospective cohort

PURPOSE

Although a number of tools have been developed to measure 'quality of life' in patients with malignant glioma, there remains no completely satisfactory technique that incorporates a quality of life measure into survival analysis. We propose that a patient's ability to maintain independent activity offers a way to accomplish this goal.

PATIENTS AND METHODS

An independent living score (ILS) is generated by awarding points on a monthly basis based on Karnofsky score and weighing the score based on the particular month of the clinical course. The ILS has a large range for any given survival, and can discriminate important treatment effects to which standard survival analyses are completely insensitive. Using this score and several variations, we were able to retrospectively analyze a patient cohort to assess what correlated with ILS.

RESULTS

We found a strong correlation with survival of all the measures tested. Interestingly, we found that patients for whom a total resection was performed and those who were most intensively treated had significantly higher ILS values, suggesting that not only did more aggressive treatment improve survival but that it did not simply increase survival at the expense of the time a patient remained independent.

CONCLUSION

Since the general course for patients with malignant glioma is one of increasing disability and loss of independence, we feel that these measures can serve as a way to distinguish between those therapies that increase survival at the expense of quality of life versus those that do not. Consideration should be given to incorporating these measures into prospective trials.

Intrathecal treatment of neoplastic meningitis due to breast cancer with a slow-release formulation of cytarabine

DepoCyte is a slow-release formulation of cytarabine designed for intrathecal administration. The goal of this multi-centre cohort study was to determine the safety and efficacy of DepoCyte for the intrathecal treatment of neoplastic meningitis due to breast cancer. DepoCyte 50 mg was injected once every 2 weeks for one month of induction therapy; responding patients were treated with an additional 3 months of consolidation therapy. All patients had metastatic breast cancer and a positive CSF cytology or neurologic findings characteristic of neoplastic meningitis. The median number of DepoCyte doses was 3, and 85% of patients completed the planned 1 month induction. Median follow up is currently 19 months. The primary endpoint was response, defined as conversion of the CSF cytology from positive to negative at all sites known to be positive, and the absence of neurologic progression at the time the cytologic conversion was documented. The response rate among the 43 evaluable patients was 28% (CI 95%: 14-41%); the intent-to-treat response rate was 21% (CI 95%: 12-34%). Median time to neurologic progression was 49 days (range 1-515(+)); median survival was 88 days (range 1-515(+)), and 1 year survival is projected to be 19%. The major adverse events were headache and arachnoiditis. When drug-related, these were largely of low grade, transient and reversible. Headache occurred on 11% of cycles; 90% were grade 1 or 2. Arachnoiditis occurred on 19% of cycles; 88% were grade 1 or 2. DepoCyte demonstrated activity in neoplastic meningitis due to breast cancer that is comparable to results reported with conventional intrathecal agents. However, this activity was achieved with one fourth as many intrathecal injections as typically required in conventional therapy. The every 2 week dose schedule is a major advantage for both patients and physicians.

Practice parameters for the management of single brain metastasis

Object

In January 1998 the Guidelines and Outcomes Committee of the American Association of Neurological Surgeons (AANS) issued a charge for the development of evidence-based practice parameters focusing on the treatment of patients with single metastasis to the brain. The charge was imposed in response to the significant controversy surrounding questions relating to the optimal management strategies for patients with single brain metastasis.

Methods

A team consisting of physicians from the AANS, the American Academy of Neurology, and the American Association of Therapeutic Radiation Oncology convened and the literature was reviewed. Methodically drawing from the best of Class I, II, and III levels of available evidence, authors sought to determine how the literature addressed and disposed of the question of the optimal management for an adult with a known history of cancer and a single meta-static brain lesion. Framing the question in this specific manner allowed researchers to focus directly on treatment issues, without having to consider diagnostic issues.

Conclusions

The results of the evidence-based analysis demonstrated that there was insufficient information to establish standards of care. Data from the literature does, however, support a guideline stating that surgical resection accompanied by whole brain radiation therapy is associated with the best survival rate. Additional lower-quality evidence supports an option for management with radiosurgery.

Quantitative analysis of the loss of distinction between gray and white matter in comatose patients after cardiac arrest

BACKGROUND AND PURPOSE

Anecdotal reports suggest that a loss of distinction between gray (GM) and white matter (WM) as adjudged by CT scan predicts poor outcome in comatose patients after cardiac arrest. To address this, we quantitatively assessed GM and WM intensities at various brain levels in comatose patients after cardiac arrest.

METHODS

Patients for whom consultation was requested within 24 hours of a cardiac arrest were identified with the use of a computerized database that tracks neurological consultations at our institution. Twenty-five comatose patients were identified for whom complete medical records and CT scans were available for review. Twenty-five consecutive patients for whom a CT scan was interpreted as normal served as controls. Hounsfield units (HUs) were measured in small defined areas obtained from axial images at the levels of the basal ganglia, centrum semiovale, and high convexity area.

RESULTS

At each level tested, lower GM intensity and higher WM intensity were noted in comatose patients compared with normal controls. The GM/WM ratio was significantly lower among comatose patients compared with controls (P:<0.0001, rank sum test). There was essentially no overlap in GM/WM ratios between control and study patients. The difference was greatest at the basal ganglia level. We also observed a marginally significant difference in the GM/WM ratio at the basal ganglia level between those patients who died and those who survived cardiac arrest (P:=0. 035, 1-tailed t test). Using receiver operating characteristic curve analysis, we determined that a difference in GM/WM ratio of <1.18 at the basal ganglia level was 100% predictive of death. At the basal ganglia level, none of 12 patients below this threshold survived, whereas the survival rate was 46% among patients in whom the ratio was >1.18. The empirical risk of death was 21.67 for comatose patients with a value below threshold.

CONCLUSIONS

The ratio in HUs of GM to WM provides a reproducible measure of the distinction between gray and white matter. A lower GM/WM ratio is observed in comatose patients immediately after cardiac arrest. The basal ganglia level seems to be the most sensitive location on CT for measuring this relationship. Although a GM/WM ratio <1.18 at this level predicted death in this retrospective study, the difference in this study is not robust enough to recommend that management decisions be dictated by CT results. The results, however, do warrant consideration of a prospective study to determine the reliability of CT scanning in predicting outcome for comatose patients after cardiac arrest.

A randomized controlled trial comparing intrathecal sustained-release cytarabine (DepoCyt) to intrathecal methotrexate in patients with neoplastic meningitis from solid tumors

Standard treatment for neoplastic meningitis requires frequent intrathecal (IT) injections of chemotherapy and is only modestly effective. DepoCyt is a sustained-release formulation of cytarabine that maintains cytotoxic concentrations of the drug in the cerebrospinal fluid (CSF) for more than 14 days after a single 50-mg injection. We conducted a randomized, controlled trial of DepoCyt versus methotrexate in patients with solid tumor neoplastic meningitis. Sixty-one patients with histologically proven cancer and positive CSF cytologies were randomized to receive IT DepoCyt (31 patients) or IT methotrexate (30 patients). Patients received up to six 50-mg doses of DepoCyt or up to sixteen 10-mg doses of methotrexate over 3 months. Treatment arms were well balanced with respect to demographic and disease-related characteristics. Responses occurred in 26% of DepoCyt-treated and 20% of methotrexate-treated patients (P = 0.76). Median survival was 105 days in the DepoCyt arm and 78 days in the methotrexate arm (log-rank P = 0.15). The DepoCyt group experienced a greater median time to neurological progression (58 versus 30 days; log-rank P = 0.007) and longer neoplastic meningitis-specific survival (log-rank P = 0.074; median meningitis-specific survival, 343 versus 98 days). Factors predictive of longer progression-free survival included absence of visible central nervous system disease on neuroimaging studies (P<0.001), longer pretreatment duration of CSF disease (P<0.001), history of intraparenchymal tumor (P<0.001), and treatment with DepoCyt (P = 0.002). The frequency and grade of adverse events were comparable between treatment arms. In patients with solid tumor neoplastic meningitis, DepoCyt produced a response rate comparable to that of methotrexate and significantly increased the time to neurological progression while offering the benefit of a less demanding dose schedule.

Correlates between hematopoiesis and neuropoiesis: neural stem cells

There are many parallels between the neuropoietic and lymphohematopoietic systems. The lymphohematopoietic stem/progenitor cell system has been extensively characterized, but there are still major questions relating to the definitive stem cell assay, the structure of the system (i.e., hierarchical versus cell cycle-based), and the nature of differentiation (i.e., stochastic versus deterministic). Recent data have established the existence of an epidermal growth factor (EGF)-responsive neural stem cell in adult mice. We have studied these neural progenitor/stem cells in fetal (day 15) and 2-day postnatal mice and established a single-cell progenitor assay and a variety of putative uni-, bi-, and tripotential stem cells that form in response to EGF. Neurospheres are the EGF-responsive neural units that grow in liquid culture, and we have found that cells derived from these neurospheres express a wide array of cytokines and their receptors. This will provide a window on the hemopoietic progenitor system analogous to that created by the description of in vitro growth of clonal hematopoietic progenitors.

High-dose intravenous methotrexate for patients with nonleukemic leptomeningeal cancer: is intrathecal chemotherapy necessary?

PURPOSE

Standard treatments for neoplastic meningitis are only modestly effective and are associated with significant morbidity. Isolated reports suggest that concurrent systemic and intrathecal (i.t.) therapy may be more effective than i.t. therapy alone. We present our experience, which includes CSF and serum pharmacokinetic data, on the use of high-dose (HD) intravenous (i.v.) methotrexate (MTX) as the sole treatment for neoplastic meningitis.

PATIENTS AND METHODS

Sixteen patients with solid-tumor neoplastic meningitis received one to four courses (mean, 2.3 courses) of HD (8 g/m2 over 4 hours) i.v. MTX and leucovorin rescue. Serum and CSF MTX concentrations were measured daily. Toxicity, response, and survival were retrospectively compared with a reference group of 15 patients treated with standard i.t. MTX during the same time interval.

RESULTS

Peak methotrexate concentrations ranged from 3.7 to 55 micromol/L (mean, 17.1 micromol/L) in CSF and 178 to 1,700 micromol/L (mean, 779 micromol/L) in serum. Cytotoxic CSF and serum MTX concentrations were maintained much longer than with i.t. dosing. Toxicity was minimal. Cytologic clearing was seen in 81% of patients compared with 60% of patients treated intrathecally (P = .3). Median survival in the HD i.v. MTX group was 13.8 months versus 2.3 months in the i.t. MTX group (P = .003).

CONCLUSION

HD i.v. MTX is easily administered and well tolerated. This regimen achieves prolonged cytotoxic serum MTX concentrations and CSF concentrations at least comparable to those achieved with standard i.t. therapy. Cytologic clearing and survival may be superior in patients treated with HD i.v. MTX. Prospective studies and a reconsideration of the use of i.t. chemotherapy for patients with neoplastic meningitis are warranted.

In vitro cell density-dependent clonal growth of EGF-responsive murine neural progenitor cells under serum-free conditions

Neural progenitor cell populations responsive to epidermal growth factor (EGF) have been shown to have proliferative potential and give rise to neurons, astrocytes, and oligodendrocytes. We have characterized EGF-responsive neural progenitor cells that give rise to bilineage neuronal/glial colonies (colony-forming unit neuron-glia; CFU-NeGl) and unilineage neuronal colonies (CFU-Ne). Clonality was confirmed utilizing mixtures of brain cells from Balb/c and ROSA26 (transgenic for beta-galactosidase) mice. With a few exceptions, colonies showed either all blue cells or all clear cells after staining with X-Gal. Clonal growth was analyzed after 10-11 days in relation to cell density by determining colony size and plating efficiency. Growth was density dependent (no growth below 10,000 cell/ml) and thus single cell cloning was not accomplished. An average plating efficiency of 4% was found for EGF-responsive neural cells derived from day 15-18 murine embryos when cultured at 12,500 to 200,000 cells/ml. Similar results were obtained with 1-day-old postnatal neural cells. When colonies were categorized by size, the relative number of colonies over 50 cells appeared to be maximum at 50,000 plated cells/ml. After 11 days in culture, 94, 96, and 78% of the colonies contained cells that expressed nestin, neurofilament, and GFAP, respectively. Double-label experiments revealed that > 62% of the colonies contained both GFAP and neurofilament expressing cells. These studies establish the existence of at least two populations of clonal neural progenitors: CFU-Ne and CFU-NeGl in fetal and postnatal murine brain.

Cerebral demyelination syndrome in a patient treated with 5-fluorouracil and levamisole. The use of thallium SPECT imaging to assist in noninvasive diagnosis--a case report

BACKGROUND

The use of 5-fluorouracil (5-FU) and levamisole in patients with Stage III adenocarcinoma of the colon has now become standard. There have been several reports of a multifocal cerebral demyelination syndrome following 5-FU and levamisole administration.

METHODS

We describe a patient who developed focal neurologic symptoms while being treated with levamisole and 5-FU in whom the diagnosis of central nervous system (CNS) metastases was considered.

RESULTS

A magnetic resonance imaging (MRI) scan showed a diffuse, multifocal white matter process. Diagnostic evaluation did not support a diagnosis of CNS metastasis. 201Thallium chloride single photon emission computed tomography (SPECT) study was cold. A stereotactic brain biopsy disclosed demyelination but not tumor. The patient had complete functional resolution of symptoms with 1 month of dexamethasone therapy, although follow-up MRI scans have shown persistent abnormality on T2-weighted images.

CONCLUSIONS

In patients receiving 5-FU and levamisole who develop focal neurologic symptoms with an abnormal MRI scan, the diagnosis of CNS metastasis should not be made without a thorough diagnostic evaluation. We suggest the use of 201thallium chloride SPECT imaging to support the diagnosis of multifocal leukoencephalopathy related to 5-FU and levamisole. In atypical cases, a stereotactic brain biopsy may be required for confirmation.

Cortical blindness after correction of symptomatic hyponatremia: dynamic cerebral dysfunction visualized using serial SPECT scanning

A 70-yr-old woman developed cortical blindness after correction of hyponatremia. Regional hyperperfusion was noted on SPECT scans obtained in the acute phase. One month later when symptoms had largely resolved, a repeat examination was normal. This regional hyperperfusion, which was not associated with any apparent structural damage, may have represented either luxury perfusion or a transient increased metabolic requirement of the dysfunctional cortical area. SPECT scanning may be a useful method to study cerebral dysfunction resulting from an osmotic disturbance.

Should cerebral ischemic events in cancer patients be considered a manifestation of hypercoagulability?

BACKGROUND AND PURPOSE

Previous studies, mainly autopsy-based, suggest that the spectrum of stroke in cancer patients differs from that of the general population. These studies also suggest that cerebrovascular events frequently are a manifestation of hypercoagulability. However, no studies that address this question in the adult oncological population from a clinical perspective are available. We therefore assessed the clinical impact of cerebral ischemic events in cancer patients and attempted to determine whether their occurrence represents a manifestation of Trousseau's syndrome.

METHODS

A computerized database that records all neurological admissions and consultations at a tertiary medical center was used to retrospectively identify all patients with cerebral ischemic events and cancer.

RESULTS

Thirty-three patients representing 3.5% of all stroke consultations and admissions seen at the University of Massachusetts Medical Center were identified during the period 1988 through 1992. Large-vessel atherosclerosis was the most frequent cause of stroke. Furthermore, although 30% were determined to have hypercoagulability as a cause using clinical criteria, in only one of nine patients in whom tests were done was sufficient evidence present to make a presumptive diagnosis of disseminated intravascular coagulation. Irrespective of therapy, recurrent cerebral ischemic events were noted in only 6% of patients during a follow-up period averaging greater than 9 months, a figure that is similar to that for the risk of repeated events in the noncancer population.

CONCLUSIONS

Recognizing the limitations of this retrospective study, it appears nonetheless that conventional stroke origins account for the majority of cerebral ischemic events in the adult cancer population. Although hypercoagulability is present to a greater extent than in the nononcological population, recurrent strokes seem to occur no more frequently than in the nononcological population, and antiplatelet agents seem sufficient therapy for most patients.

Potentiation of antitumor immunotoxins by liposomal monensin

BACKGROUND

The cytotoxicity of specific ricin A-chain immunotoxins is greatly enhanced in vitro by the carboxylic ionophore monensin. However, the highly lipophilic nature of monensin, which is reflected in its poor solubility and short half-life, has restricted its use in in vivo animal studies.

PURPOSE

The purpose of this study was to assess the ability of monensin incorporated in unilamellar vesicles (liposomes) to potentiate antitumor immunotoxins in vitro and in vivo.

METHODS

Monensin was incorporated into liposomes and used in combination with specific immunotoxins against human tumor cell lines in vitro and in vivo. Inhibition of [3H]leucine incorporation was used to evaluate the cytotoxic action of immunotoxin with or without monensin in vitro on the following human tumor cell lines: H-MESO-1 malignant mesothelioma, LS174T colorectal carcinoma, and U373, U87, and MG-1 glioblastomas. For the in vivo studies of immunotoxins and liposomal monensin, BALB/c nu/nu mice were inoculated intraperitoneally with H-MESO-1 cells.

RESULTS

Liposomal monensin potentiated the cytotoxic action of cell-specific anti-human transferrin receptor immunotoxin on H-MESO-1 target cells at a molar concentration of monensin that was 160-fold lower than the concentration of monensin in buffer that produced the same effect (0.3 nM versus 0.05 microM). Moreover, immunotoxin plus 0.1 microM liposomal monensin was fivefold more toxic for H-MESO-1 cells and 1000-fold and 2200-fold more toxic for human glioblastoma U373 and U87 cells, respectively, than immunotoxin plus 0.1 microM free monensin in buffer. Liposomal monensin produced similar effects when it was combined with different specific immunotoxins and other target cell lines (i.e., LS174T, U87, and CEM). Immunotoxin specificity was preserved with liposomal monensin, as shown by the absence of effect with non-cell-binding immunotoxins or on antigen-negative cell lines. In mice, liposomal monensin in combination with specific immunotoxin substantially prolonged survival, and three (21%) of 14 mice bearing H-MESO-1 xenografts treated with the liposomes showed no evidence of tumor at day 160 after treatment. Treatment with control immunotoxin plus liposomal monensin was ineffective.

CONCLUSION

These findings suggest that encapsulation of monensin into liposomes increased the capacity of monensin to enhance the potency of cell-specific immunotoxin in vitro and in vivo.

A comparison of two-dimensional echocardiography vs carotid duplex scanning in older patients with cerebral ischemia

BACKGROUND

To determine the relative value of two-dimensional (2D) echocardiography vs carotid duplex scanning and to devise an optimal, cost-effective diagnostic approach for older patients with cerebral ischemia, 68 consecutive patients in sinus rhythm who suffered focal cerebral ischemia were studied. All patients underwent 2D echocardiography and carotid duplex scanning in addition to routine clinical evaluation.

METHODS

Twenty-five of 68 patients had Q-wave myocardial infarction by electrocardiography; nine (36%) of these 25 had left ventricular mural thrombi demonstrated by 2D echocardiography. In contrast, none of 43 patients without Q-wave myocardial infarction had clinically unsuspected findings diagnosed by 2D echocardiography. Duplex scanning, however, identified significant, abnormal findings in the carotid artery ipsilateral to the involved cerebral hemisphere in 23 patients (34%).

CONCLUSIONS

Thus, in older patients in sinus rhythm who suffer a cerebral ischemic event, carotid duplex scanning has a higher diagnostic yield than 2D echocardiography and appears to be a more cost-effective initial test. Our data suggest that in patients with carotid distribution cerebral ischemic events and no obvious cardiac source for emboli by history and physical examination, 2D echocardiography should be limited to those with evidence of Q-wave myocardial infarction by electrocardiography; such management should optimize diagnostic yield and cost effectiveness.

Impairment of grip function in rheumatoid arthritis--studies with a simple hand test

A new, simple and quick method for assessment of impaired grip function was evaluated in a rheumatology department, 208 of 211 patients with definite rheumatoid arthritis were unable to do the test, 48 of these patients had regarded their hands as unaffected when questioned. The impairment of grip function was closely related to clinical and functional observations but not related to the most common laboratory tests. The study confirms the hypothesis that almost all patients with RA are unable to do the hand test, even those who consider their hand function as normal.

Construction of a simple test for assessment of hand function in primary care. Theories and experimental trials for the test situation

This paper describes a hand test consisting of three steps to test the subject's ability to grasp firmly another person's hand to hold a pencil firmly with fingers II-V with straight knuckles and maximally flexed finger joints, while the investigator pulls the pencil to hold on to a piece of paper with a rounded pinch grip between thumb and index finger while the investigator pulls the paper with a rounded pinch grip with submaximal strength. All three steps must be performed with each hand without causing pain. The test was an adequate parameter for the grip function, and at the same time could register work-load elicited pain, strength, and mobility. The test can be carried out by healthy subjects, but not by patients with rheumatoid arthritis. The test is logically constructed and has a high validity and reliability.

Transferrin receptor in normal and neoplastic brain tissue: implications for brain-tumor immunotherapy

The distribution of transferrin receptor (TfR) in normal human brain-tissue obtained at autopsy and in brain-tumor biopsy specimens from 27 patients was determined by immunohistochemistry using two specific murine monoclonal antibodies against human TfR. The tumors studied included 10 glioblastomas multiforme (GBM's), nine other glial tumors, and eight meningiomas. In normal brain, TfR was detected primarily in endothelial cells; rare glial cells also contained immunoreactive product. All tumors contained TfR-positive cells, although the intensity (number of cells stained) and pattern (focal vs. diffuse) of staining varied with the histopathological type of the tumor. Among gliomas, the most intense staining was seen in GBM's, especially in areas of pseudopalisading where virtually all cells were stained. A rough correlation between tumor grade, number of positively stained cells, and staining pattern was seen in the other astrocytic tumors. By contrast, all meningiomas demonstrated an identical and characteristic focal staining pattern. Considering the differential immunostaining for TfR between normal and neoplastic tissue, the authors conclude that TfR may be an appropriate target for monoclonal antibody-directed brain-tumor immunotherapy, especially in more malignant tumors such as GBM's.

Preirradiation chemotherapy of supratentorial malignant primary brain tumors with intracarotid cis-platinum (CDDP) and i.v. BCNU. A phase II trial

Thirty patients with histologically verified malignant supratentorial gliomas were treated with a preirradiation chemotherapy protocol consisting of two courses of intracarotid (i.c.) CDDP, 90 mg/m2, followed by i.v. BCNU, 200 mg/m2. Side effects from therapy were mild and self-limiting; no irreversible retinal or neurologic toxicity could be attributed to i.c. chemotherapy. Of the 27 patients who completed the chemotherapy portion of the protocol, tumor size on postchemotherapy computed tomography (CT) was decreased by greater than 50% in 13% as compared to the postoperative CT scan; in only 4% was the CT scan unequivocally increased in size. Twenty-five (83%) patients completed the entire protocol. Median time to tumor progression and survival in patients who completed the protocol was 53 (range of 13-130+) and 61 (range of 29-130+) weeks, respectively. Twenty-four percent of patients still have not demonstrated tumor progression at intervals greater than 1 year after diagnosis as judged by clinical and radiographic criteria. Tumor recurrences were always contiguous to the original tumor bed. We conclude that preirradiation chemotherapy may be administered safely and with low morbidity. Further study to determine an optimal timing between chemotherapy and radiation therapy is warranted.