Previous Midlife Oestradiol Treatment Results in Long-Term Maintenance of Hippocampal Oestrogen Receptor α Levels in Ovariectomised Rats: Mechanisms and Implications for Memory.

Ovariectomised rats that have received previous administration of oestradiol in midlife display enhanced cognition and increased hippocampal levels of oestrogen receptor (ER)α months after oestradiol treatment ended compared to ovariectomised controls. The present study aimed to investigate the mechanisms by which ERα levels are maintained following midlife oestradiol exposure and the role of ERα in memory in ageing females in the absence of circulating oestrogens. Unliganded ERα has increased interaction with the ubiquitin ligase, C-terminus of Hsc-70 interacting protein (CHIP), leading to increased degradation of the receptor. In our first experiment, we tested the hypothesis that midlife oestradiol exposure in ovariectomised rats results in decreased interaction between CHIP and hippocampal ERα, leading to increased levels of ERα. Middle-aged rats were ovariectomised and received oestradiol or vehicle implants. After 40 days, implants were removed. One month later, rats were killed and hippocampi were processed for whole protein western blotting and co-immunoprecipitation, in which ERα was immunoprecipitated from lysate. As expected, ERα protein expression was increased in rats previously treated with oestradiol compared to vehicle-treated rats. In rats treated with oestradiol, there was a decrease in CHIP-ERα interaction, suggesting that previous oestradiol treatment reduces interaction, slowing the degradation of ERα. In a second experiment, we determined the impact on memory of antagonism of ER in the absence of circulating oestrogens. Rats were ovariectomised and implanted with oestradiol capsules. Capsules were removed after 40 days. Rats received chronic i.c.v. infusion of ER antagonist, ICI 182 780, or artificial cerebrospinal fluid vehicle and were tested on a spatial memory radial-maze task. Rats treated with ICI 182 780 had significantly worse performance (more errors). These experiments provide evidence that previous midlife oestradiol treatment maintains hippocampal ERα by decreasing its interaction with CHIP and that activation of these receptors provides cognitive benefits in the absence of circulating oestrogens.

Urinary tract infections in meningioma patients: analysis of risk factors and outcomes.

BACKGROUND: Urinary tract infections (UTIs) account for about 35% of all nosocomial infections and 75% are associated with the use of urethral catheters. AIM: The goal of this study was to evaluate preoperative factors associated with the risk of UTI and to estimate the impact of UTIs on patient outcome and resource utilization. METHODS: Adult meningioma patients treated with craniotomy in US hospitals between 2002 and 2007 were queried from the Nationwide Inpatient Sample (NIS) database. Univariate and multivariate analyses that correct for sample survey design data were used to study the association of perioperative UTIs and outcomes. FINDINGS: In all, 46,344 patients were included. Women comprised the majority (70.0%), had lower mortality (1.2% vs 2.0%), shorter in-hospital stay (6.7 vs 7.5 days), lower hospital charges (US$76,682 vs 87,220) and higher UTI rates (6.3% vs 3.9%) than men. In multivariate analysis, female gender (odds ratio: 2.2; P < 0.0001), older age (1.4; P < 0.001), emergency room admissions (1.8; P < 0.0001), total length of stay (1.08; P < 0.0001), comorbidity score (1.04; P = 0.0147), postoperative fluid abnormalities (1.96; P < 0.0001) and pulmonary complications (1.3; P < 0.0011) were associated with UTI. UTI was associated with an additional 2.3 days of hospital stay and an incremental US$18,920 in hospital charges. CONCLUSIONS: Perioperative UTIs are associated with specific comorbidities and postoperative complications. They significantly increase in-hospital length of stay and costs. Our data emphasize the need to support national efforts that are underway to reduce hospital-acquired UTIs within the neurosurgical population.

miR-34a functions as a tumor suppressor modulating EGFR in glioblastoma multiforme.

Chromosome 1p36.23 is frequently deleted in glioblastoma multiforme (GBM). miR-34a localizes in this region. Our experiments found that miR-34a was often deleted and epidermal growth factor receptor (EGFR) was frequently amplified in genomic DNA of 55 GBMs using single-nucleotide polymorphism DNA microarray. Notably, we found that the mean survival time was significantly shortened for patients whose GBMs had both EGFR amplification and miR-34a deletion. Expression of miR-34a was significantly lower in GBM samples compared with normal brain tissue. Forced expression of miR-34a in GBM cells decreased their ability to migrate and profoundly decreased their levels of cyclin-A1, -B1, -D1, and -D3, as well as cyclin-dependent kinase and increased expression of cyclin kinase inhibitor proteins (p21, p27). Also, human GBM cells (U251) stable overexpressing mir-34a formed smaller tumors when growing as xenografts in immunodeficient mice compared with wild-type U251 GBM cells. Furthermore, the protein expression of EGFR decreased in the cells with forced overexpression of miR-34a. Additional studies showed that mir-34a targeted Yin Yang-1 (YY1) and YY1 is a transcription factor that can stimulate the expression of EGFR. Thus, our data suggest that miR-34a acts as a tumor suppressor by inhibiting growth of GBM cells in vitro and in vivo associated with moderating the expression of cell-cycle proteins and EGFR. Moreover, we discovered for the first time that both deletion of miR-34a and amplification of EGFR were associated with significantly decreased overall survival of GBM patients.

Isolation of tumour stem-like cells from benign tumours.

BACKGROUND: Cancerous stem-like cells (CSCs) have been implicated as cancer-initiating cells in a range of malignant tumours. Diverse genetic programs regulate CSC behaviours, and CSCs from glioblastoma patients are qualitatively distinct from each other. The intrinsic connection between the presence of CSCs and malignancy is unclear. We set out to test whether tumour stem-like cells can be identified from benign tumours. METHODS: Tumour sphere cultures were derived from hormone-positive and -negative pituitary adenomas. Characterisation of tumour stem-like cells in vitro was performed using self-renewal assays, stem cell-associated marker expression analysis, differentiation, and stimulated hormone production assays. The tumour-initiating capability of these tumour stem-like cells was tested in serial brain tumour transplantation experiments using SCID mice. RESULTS: In this study, we isolated sphere-forming, self-renewable, and multipotent stem-like cells from pituitary adenomas, which are benign tumours. We found that pituitary adenoma stem-like cells (PASCs), compared with their differentiated daughter cells, expressed increased levels of stem cell-associated gene products, antiapoptotic proteins, and pituitary progenitor cell markers. Similar to CSCs isolated from glioblastomas, PASCs are more resistant to chemotherapeutics than their differentiated daughter cells. Furthermore, differentiated PASCs responded to stimulation with hypothalamic hormones and produced corresponding pituitary hormones that are reflective of the phenotypes of the primary pituitary tumours. Finally, we demonstrated that PASCs are pituitary tumour-initiating cells in serial transplantation animal experiments. CONCLUSION: This study for the first time indicates that stem-like cells are present in benign tumours. The conclusions from this study may have applications to understanding pituitary tumour biology and therapies, as well as implications for the notion of tumour-initiating cells in general.

Novel uses of insulin syringes to reduce dosing errors: a retrospective chart review of enoxaparin whole milligram dosing.

UNLABELLED: Enoxaparin is a low molecular weight heparin (LMWH) commonly used for thromboprophylaxis children. Enoxaparin dosing is based on patients' weight and results in decimal dosing. Due to the high concentration of enoxaparin the resultant decimal dose makes precise measurement difficult. Dilution is necessary and often results in ten-fold medication administration errors [Ghaleb MA, Barber N, Franklin BD, Yeung VWS, Khaki ZF, Wong ICK. Systematic review of medication errors in pediatric patients. Ann Pharmacother Oct 2006;40(10):1766-76, Raju TN, Kecskes S, Thornton JP, Perry M, Feldman S. Medication errors in neonatal and paediatric intensive-care units. Lancet Aug 12 1989;2(8659):374-6]. Enoxaparin may be administered in whole milligram doses via insulin syringe, where one milligram of enoxaparin equals one unit on the 100 unit graduated insulin syringe. STUDY DESIGN: A retrospective chart review of 514 children. Data was collected on underlying diagnosis, reason for anticoagulation, anti-Xa levels, hemorrhagic events, and medication errors identified. OUTCOME: to determine the occurrence rate of supra-therapeutic anticoagulation as indicated by anti-Xa levels >1.0 u/ml, when enoxaparin doses are rounded up to the whole milligram, and are administered using insulin syringes. The secondary objectives were to determine if the supra-therapeutic anti-Xa levels were associated with hemorrhagic events. To determine if children achieved and maintained therapeutic anti-Xa range using whole milligram dosing and to evaluate the impact of utilizing insulin syringes for administration on reducing dose measurement errors. RESULTS: All 514 patients were prescribed whole milligram enoxaparin dosing, and achieved therapeutic anti-Xa within a mean time of 2 days. No infant or child required decimal doses to achieve therapeutic levels. Five children achieved an initial supra-therapeutic anti-Xa level (1.04 -1.36 U/ml), requiring a single whole milligram dose decrease. There were no associated hemorrhagic events. CONCLUSION: Whole milligram enoxaparin dosing administered via an insulin syringe safely and effectively, achieved therapeutic levels in infants and children. The reduced incidence of enoxaparin dosing errors suggests that whole milligram enoxaparin dosing via an insulin syringe is a method that should be considered for standard of care.

DLK1: increased expression in gliomas and associated with oncogenic activities.

DLK1 (delta-like) is a transmembrane and secreted protein in the epidermal growth factor-like homeotic family. Although expressed widely during embryonic development, only a few tissues retain the expression in adults. Neuroendocrine tumors often highly express this protein; therefore, we hypothesized that brain tumors might also express it. This study found that the expression of DLK1 in gliomas was higher than that in normal brain (P < 0.05). After stable transfection of a DLK1 cDNA expression vector into GBM cell lines, their proliferation was increased. Furthermore, they lost contact inhibition, had enhanced anchorage-independent growth in soft agar, and had significantly greater capacity to migrate. Western blot studies showed that expression of cyclin D1, CDK2, and E2F4 were increased, and Rb levels were decreased in these cells. DLK1 was found on the cell surface and secreted in the medium from the transfected GBM cells. DLK1-enriched condition medium stimulated the growth of glioblastoma multiforme cell lines and explants. DLK1 antibody blocked cell growth stimulated by DLK1. In summary, these results suggest that DLK1 may play a role in the formation or progression of gliomas.

Repeated, short-term ischemia augments bradykinin-mediated opening of the blood-tumor barrier in rats with RG2 glioma.

The objective of this study was to investigate the effects of repeated, short-term ischemia on bradykinin-mediated permeability of the blood-brain barrier (BBB) and the blood-tumor barrier (BTB). The mechanism by which bradykinin transiently opens the BTB, involves B2 receptors, Ca2+ flux, nitric oxide (NO) and cyclic GMP (cGMP). Since global and focal cerebral ischemia are known to increase levels of brain nitric oxide synthase (bNOS) and endothelial nitric oxide synthase (eNOS) we tested the hypothesis that bradykinin may increase the BTB permeability to a greater extent under ischemic rather than nonischemic conditions. The vertebral arteries in female Wistar rats were coagulated immediately after intracerebral implantation of RG2 glioma. Short-term ischemia was produced in some rats by a modification of the four-vessel occlusion procedure for incomplete forebrain ischemia, in which the common carotid arteries were clamped daily for 15 min on days 7, 8 and 9 after tumor implantation, after which reperfusion was allowed. On day 10 after tumor implantation, bradykinin (10 microg kg(-1) min(-1)) or phosphate-buffered saline (PBS) was infused for 15 min into the right carotid artery of anesthetized, sham-operated (nonischemic controls) and ischemic rats, followed by an intravenous bolus (100 microCi kg(-1)) each of [14C]-iodo-antipyrine (IAP), [14C]-dextran or [14C]-aminoisobutyric acid (AIB) to measure regional cerebral blood flow (rCBF), blood volume, or unidirectional transfer constant Ki, respectively, by quantitative autoradiography. A single 15-min ischemic episode significantly decreased rCBF in the tumor center (158.9 +/- 17.33 in control vs. 58.78 +/- 24.45 ml 100 g(-1) min(-1) in ischemic group; p < 0.01) and in the tumor periphery (106.82 +/- 7.34 in control vs. 70.55 +/- 26.66 ml 100 g(-1) min(-1) in ischemic group; p < 0.05). Respective mean blood volume in tumors (11.7 +/- 13.3, 12.7 +/- 14.0, and 13.3 +/- 14.5 microl g(-1)) from ischemic-PBS, nonischemic-bradykinin, and ischemic-bradykinin groups, respectively, was not significantly different; mean blood volume in normal brain (3.7, 3.1 and 3.8 microl g(-1)) was not significantly different among these groups either. Intracarotid infusion of bradykinin following repeated ischemia significantly increased mean Ki, as compared to bradykinin infusion in nonischemic controls, in both the tumor center (36.60 +/- 8.4 vs. 22.90 +/- 4.61 microl g(-1) min(-1), p < 0.05) and in tumor periphery (17.70 +/- 5.93 vs. 8.50 +/- 4.42 microl g(-1) min(-1), p < 0.05). Mean Ki values for tumor center and tumor periphery of ischemic rats receiving intracarotid bradykinin were 3-fold greater than those of nonischemic rats infused with PBS. Immunohistochemical and Western blot analyses showed that repeated, short-term ischemia significantly increased the levels of bNOS in tumor cells and eNOS in tumor capillaries, but neither induced iNOS nor affected B2 receptor levels in tumor cells in vivo, as compared with nonischemic controls. Taken together, these results demonstrate for the first time that repeated, short-term ischemia augments bradykinin-mediated opening of the BTB. We conclude that the elevated intratumoral levels of bNOS and eNOS may 'prime' the NO generating capacity of tumor cells. Consequently, increased de novo synthesis and a correspondingly elevated concentration of NO within the tumor, therefore, may be one mechanistic explanation for the significantly increased, bradykinin-mediated BTB opening under ischemic conditions, reported here.

Overexpression of alpha4 chain-containing laminins in human glial tumors identified by gene microarray analysis.

Differential gene expression in tumors often involves growth factors and extracellular matrix/basement membrane components. Here, 11,000- gene microarray was used to identify gene expression profiles in brain tumors including high-grade gliomas [glioblastoma multiforme (GBM) and anaplastic astrocytoma], low-grade astrocytomas, or benign extra-axial brain tumors (meningioma) in comparison with normal brain tissue. Histologically normal tissues adjacent to GBMs were also studied. All GBMs studied overexpressed 14 known genes compared with normal human brain tissue. Overexpressed genes belonged to two broad groups: (a) growth factor-related genes; and (b) structural/extracellular matrix-related genes. For most of these 14 genes, expression levels were lower in low-grade astrocytoma than in GBM and were barely detectable in normal brain. Despite normal-appearing histology, gene expression patterns of tissues immediately adjacent to GBM were similar to those of their respective primary GBMs. Two genes were consistently up-regulated in both high-grade and low-grade gliomas, as well as in histologically normal tissues adjacent to GBMs. These genes coded for the epidermal growth factor receptor (previously reported to be overexpressed in gliomas) and for the alpha4 chain of laminin, a major blood vessel basement membrane component. Changes in expression of this laminin chain have not been previously associated with malignant tumors. Overexpression of laminin alpha4 chain in GBM and astrocytoma grade II by gene microarray analysis was confirmed by semiquantitive reverse transcription-PCR and immunohistochemistry. Importantly, an alpha4 chain-containing laminin isoform, laminin-8 (alpha4beta1gamma1), was expressed mainly in blood vessel walls of GBMs and histologically normal tissues adjacent to GBMs, whereas another alpha4 chain-containing laminin isoform, laminin-9 (alpha4beta2gamma1), was expressed mainly in blood vessel walls of low-grade tumors and normal brain. GBMs that overexpressed laminin-8 had a shorter mean time to tumor recurrence (4.3 months) than GBMs with overexpression of laminin-9 (9.7 months, P = 0.0007). Up-regulation of alpha4 chain-containing laminins could be important for the development of glioma-induced neovascularization and glial tumor progression. Overexpression of laminin-8 may be predictive of glioma recurrence.

Modified immunoregulation associated with interferon-gamma treatment of rat glioma.

Little is known about modulation by cytokines of major histocompatibility complex (MHC) antigen expression on intracranial tumors in vivo. The ability of cytokines to up-regulate MHC class-1 (MHC-1) antigen expression was investigated first in vitro using three rat glioma cell lines. Immunohistochemistry showed that incubation with recombinant rat interferon-gamma (rrIFN-gamma) increased MHC-1 antigen expression in RG2, C6, and 9L cell lines. Flow cytometric analysis revealed different baseline levels of MHC-1 antigen expression in each line (RG2 lowest, C6 highest), and that these levels increased in all lines after stimulation with 100 U ml(-1) or more of rrIFN-gamma. The antitumor effect of rrIFN-gamma in vivo was evaluated by assessing survival of rats with implanted intracerebral RG2 gliomas after intracarotid infusion of rrIFN-gamma. A high dose of rrIFN-gamma (2.4 x 10(5) U kg(-1)) significantly increased the survival, compared to control (p < 0.02). Intracarotid pre-treatment with the bradykinin analogue RMP-7 did not further increase survival. Immunohistochemical staining of tumor sections after in vivo rrIFN-gamma, infusion showed no clear increase in MHC-1 antigen expression on tumor cells but increased staining for ED2 antigen within tumor tissue, presumably from perivascular cells with MHC class-2 antigen.

Correlation between bradykinin-induced blood-tumor barrier permeability and B2 receptor expression in experimental brain tumors.

Localization of B2 receptors in brain tumor cells and microvessel endothelial cells of the brain tumors was investigated to study the differential sensitivity of brain tumors to bradykinin. The present study shows that B2 receptor expression levels vary in cultured RG2, C6 and 9L glioma cells as well as in the intracerebral tumors established with these cell lines in rats. The double immunohistochemical data indicate that B2 receptors are localized to tumor cells and not to the tumor capillaries. Immunostaining and Western blot analysis for B2 receptor showed that the B2 receptor expression was in the order C6 > RG2 > 9L. The permeability studies on RG2, C6 and 9L tumors in rats showed that C6 tumor had the highest increase (178%) in Ki (unidirectional transport across blood-brain barrier (BBB)/blood-tumor barrier (BTB)), while 9L tumor had the least increase of Ki (35%) over the control group, following intracarotid infusion of bradykinin. We found a positive correlation (r = 0.965, p < 0.001) between B2 receptor levels and bradykinin-induced increase in BTB permeability. We conclude that B2 receptors are localized to tumor cells and not to normal or tumor capillary endothelial cells. C6 tumor with highest B2 receptor expression was most responsive to bradykinin, while RG2 and 9L tumors with lower B2 receptor expression level were less sensitive to bradykinin with regard to BTB permeability.

A herpes simplex virus type 1 mutant deleted for gamma34.5 and LAT kills glioma cells in vitro and is inhibited for in vivo reactivation.

To create an oncolytic herpes simplex virus type 1 (HSV-1) that is inhibited for reactivation, we constructed a novel herpes recombinant virus with deletions in the gamma34.5 and LAT genes. The LAT gene was replaced by the gene for green fluorescent protein, thereby allowing viral infection to be followed. This virus, designated DM33, is effective in killing primary and established human glioma cell lines in culture. DM33 is considerably less virulent following intracerebral inoculation of HSV-susceptible BALB/c mice than the wild-type HSV-1 strain McKrae. The safety of this virus is further supported by the retention of its sensitivity to ganciclovir and its relatively limited toxicity against cultured human neuronal cells, astrocytes, and endothelial cells. The ability of DM33 to spontaneously reactivate was tested in a rabbit ocular infection model that accurately depicts human herpes infection and reactivation. Following ocular infection of rabbits, spontaneous reactivation was detected in 83% (15/18) of the eyes infected with wild-type McKrae. In contrast, none of the eyes infected with DM33 had detectable reactivation. The efficacy of this virus in cultured human glioma cell lines, its safety, confirmed by its inability to reactivate, and its attenuated neurovirulence make DM33 a promising oncolytic agent for tumor therapy.

Gene expression abnormalities in human glial tumors identified by gene array.

Novel genes specific for human oligodendroglioma and glioblastoma multiforme (GBM) were detected using the gene array analysis [18,376 genes Gene Discovery Array (GDA) from Incyte Genomics, Inc.]. Eleven genes were chosen based on the highest ratios of differential expression identified by GDA between histologically normal adjacent tissue and brain tumor tissue. The differential expression of those 11 genes was verified by semiquantitative RT-PCR and Northern analysis on 22 samples of glial and other tumors of the brain, as well as of normal embryonic and adult brain tissue. Gene no. 5 (an EST) was more expressed by GDA analysis in histologically normal adjacent brain tissue than in the corresponding oligodendroglioma. By RT-PCR, this gene was expressed in a number of brain tumors but not in normal adult and embryonic brain. By GDA analysis, gene no. 7 (oligophrenin-1) gave the highest ratio compared to other genes in brain tissue adjacent to the GBM vs. GBM. By RT-PCR, oligophrenin-1 was expressed in tumors and tumor-adjacent tissue, whereas meningioma and corpus callosum were negative. Gene no. 11 (an EST) was expressed only in brain tumors but not in normal brain by Northern analysis (message size 1.5 kb) and RT-PCR. GDA analysis successfully identified genes preferentially expressed in brain tumors, which was confirmed by Northern analysis and semiquantitative RT-PCR. The validity of gene arrays for tumor-specific gene discovery is discussed. Study of differential gene expression in glial tumors should help identify the mechanism/s of transformation of normal glial cells to malignant.

Vaccination of malignant glioma patients with peptide-pulsed dendritic cells elicits systemic cytotoxicity and intracranial T-cell infiltration.

In this Phase I trial, patients' peripheral blood dendritic cells were pulsed with peptides eluted from the surface of autologous glioma cells. Three biweekly intradermal vaccinations of peptide-pulsed dendritic cells were administered to seven patients with glioblastoma multiforme and two patients with anaplastic astrocytoma. Dendritic cell vaccination elicited systemic cytotoxicity in four of seven tested patients. Robust intratumoral cytotoxic and memory T-cell infiltration was detected in two of four patients who underwent reoperation after vaccination. This Phase I study demonstrated the feasibility, safety, and bioactivity of an autologous peptide-pulsed dendritic cell vaccine for patients with malignant glioma.

Innovative cancer vaccine strategies based on the identification of tumour-associated antigens.

The identification of tumour-associated antigens has opened up new approaches to cancer immunotherapy. While past research focused on CD8+ cytotoxic T-cell responses, accumulating evidence suggests that CD4+ T cells also play an important role in orchestrating the host immune response against cancer. In this article, we summarise new strategies for the identification of major histocompatibility complex (MHC) class II-associated tumour antigens and discuss the importance of engaging both CD4+ and CD8+ T cells in cancer immunotherapy. The cloning of MHC class I- or class II-associated antigens has made it possible to develop synthetic and recombinant cancer vaccines that express specific tumour antigens. There are three major types of synthetic and recombinant cancer vaccines: recombinant viral and bacterial vaccines; naked DNA or RNA vaccines; and recombinant protein and peptide vaccines. In this article, we also discuss a new generation of recombinant cancer vaccines, 'self-replicating' DNA and RNA vaccines. Studies on the mechanisms of 'self-replicating' nucleic acid vaccines revealed that the enhanced immunogenicity was not due to an enhanced antigen expression, suggesting that the quantitative difference may not be as important as the qualitative difference in antigen presentation. The presence of the RNA replicase in the 'self-replicating' nucleic acid vaccines mimics alphavirus infection, which triggers the innate antiviral pathways of the host cells. Studies on how viral and cellular modulators of the innate antiviral pathways affect vaccine function should provide molecular insights crucial to future vaccine design.

Glioblastoma induction after radiosurgery for meningioma.

A 70-year-old woman developed a glioblastoma in the irradiated field 7 years after stereotactic radiosurgery for meningioma. Glioma induction has been previously reported after external beam radiation for leukaemia, pituitary adenoma, tinea capitus, and meningioma. This radiosurgery-induced malignancy may portend further reports of tumour induction. The theoretical risk of tumour induction by low doses of radiation to normal neural tissue after radiosurgery is now confirmed. Reports of additional cases of radiosurgery-induced tumours might temper the use of this increasingly used technique for benign surgically accessible lesions.

Response of MHC class-1 antigen on rat glioma cells to cytokines.

BACKGROUND: Enhanced MHC class-1 expression has potentially been correlated with the increased susceptibility of tumor cells to a T cell-mediated immune response. We examined the immunomodulatory effects of some cytokines on MHC class-1 expression in rat glioma cell lines. MATERIALS AND METHODS: Using three rat glioma cell lines (RG2, C6, 9L), the immunomodulatory effects of cytokines (rhIL-2, rmIL-4, rmGM-CSF, rrIFN-gamma) on the expression of MHC class-1 antigen were evaluated using immunohistochemical and flow cytometric analyses. RESULTS: Varying baseline levels of MHC class-1 antigen were confirmed in each glioma cell line. Stimulation with rrIFN-gamma consistently increased the expression of MHC-1 antigen in all three of the rat glioma cell lines. On the other hand, MHC class-1 expression was not affected by stimulation with rhIL-2, rmIL-4 or rmGM-CSF, even in combination. CONCLUSIONS: rrIFN-gamma can upregulate MHC class-1 expression in rat glioma cells. Our data suggest that rrIFN-gamma may be able to exert antitumor activity against gliomas in vivo.

Treatment of a patient by vaccination with autologous dendritic cells pulsed with allogeneic major histocompatibility complex class I-matched tumor peptides. Case Report.

Dendritic cells (DCs) are antigen-presenting cells that play a central role in the initiation and modulation of antitumor immune responses. In this pilot study, we investigated the ability of autologous DCs pulsed ex vivo with allogeneic major histocompatibility complex class I-matched glioblastoma peptides to stimulate host antitumor immune responses when injected as a vaccine. A patient with recurrent brainstem glioblastoma multiforme (GBM) received a series of three intradermal immunizations of antigen-pulsed DCs on an outpatient basis following surgical debulking of her posterior fossa tumor. Dendritic cell vaccination was well tolerated, and no clinical signs of autoimmunity or experimental allergic encephalomyelitis were detected. She developed a measurable cellular immune response against the allogeneic glioblastoma peptides used in her vaccine preparation, as demonstrated by in vitro T-cell proliferation assays. In addition, increased T-cell infiltration was noted within the intracranial tumor site in the biopsy sample obtained following DC vaccination. An objective clinical response, however, was not evident, and this patient eventually died 21 months after her disease was diagnosed. To our knowledge, this is the first patient with brain cancer ever to be treated with DC-based immunotherapy. This case illustrates that vaccination with DCs pulsed with acid-eluted glioblastoma peptides is feasible and can induce systemic antigen-specific immunity in a patient with recurrent GBM. Additional studies are necessary to determine the optimum DC doses and antigen loading conditions that may translate into clinical effectiveness and survival benefit for patients with brain tumors. Phase I trials for malignant glioma are currently underway.

MRI of thermally denatured blood: methemoglobin formation and relaxation effects.

Focal regions of T1-shortening have been observed in magnetic resonance imaging (MRI)-monitored thermal ablations of perfused tissues. The aims of this study were two-fold: to find evidence for heat-induced conversion of hemoglobin (Hb) to methemoglobin (mHb), and to investigate the effects of heat treatment of in-vitro blood components upon their MR relaxation times. Spectrophotometric studies were performed to confirm the heat-induced formation of methemoglobin. Preparations of whole and fractionated blood, previously submitted to elevated temperatures of 40 degrees C to 80 degrees C, were imaged and the relaxation times were calculated. Optical absorption spectra of samples containing free Hb, heated to 60 degrees C, showed increased light absorption at 630 nm, evident of mHb presence. Short T1 values in whole blood (1.13 s) and packed red blood cell (0.65 s) compartments, heated at 60 degrees C, compared to their baseline values (1.62 s and 0.83 s, respectively), were attributed to mHb formation. In relation to MRI-guided thermal interventions, these results suggest a possible explanation for observation of hyperintense regions on T1-weighted images.

Immunotherapy of malignant brain tumors in children and adults: from theoretical principles to clinical application.

In the span of just 10 years, our understanding of the cancer-immune system relationship has increased exponentially, and yet we are only beginning to understand the intricacies of cytokine and immune cell interactions. This paper reviews the interactions of the immune system with brain tumors. In principle, the immune system is uniquely qualified to be an instrument for cancer therapy. An immune response directed against cells bearing tumor antigens could provide a specific and effective mechanism for killing residual tumor. While the theoretical background for immunotherapy as a treatment for brain tumors is elegant and persuasive, a substantial clinical breakthrough has yet to be made. This paper reviews the major forms of both animal and human data on types of immunotherapy, such as passive serological immunotherapy, active, and adoptive immunotherapy. Next a review of existing data on effects of cytokines, immune regulation, and tumor cytotoxicity is detailed. The review concludes with the clinical trials using interferons and other methodologies. The trials presented here demonstrate the challenging work being done to take basic science into the clinical realm. As this work continues, our ability to design effective immune therapies will mature and yield increased therapeutic success.