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PubMed1994

Adenovirus-mediated gene therapy of experimental gliomas.

The efficacy of adenovirus (ADV)-mediated gene therapy to treat brain tumors was tested in a syngeneic glioma model. Tumor cells were transduced in situ with a replication-defective ADV carrying the herpes simplex virus thymidine kinase (HSV-tk) gene controlled by the Rous sarcoma virus promoter. Expression of the HSV-tk gene enables the transduced cell to convert the drug ganciclovir to a form that is cytotoxic to dividing cells. Tumors were generated in Fischer 344 rats by stereotaxic implantation of 9L gliosarcoma cells into the caudate nucleus. Eight days later, the tumors were injected either with the ADV carrying the HSV-tk (ADV-tk) gene or a control ADV vector containing the beta-galactosidase (ADV-beta gal) gene and the rats were treated with either ganciclovir or saline. Tumor size was measured 20 days after implantation of 9L cells or at death. Rats treated with ADV-beta gal and ganciclovir or with ADV-tk and saline had large tumors. No tumors were detected in animals treated with ADV-tk and with ganciclovir at doses > or = 80 mg/kg. An infiltrate of macrophages and lymphocytes at the injection site in animals treated with ADV-tk and ganciclovir indicated an active local immune reaction. In survival studies, all animals treated with ADV-tk and ganciclovir have remained alive longer than 80 and up to 120 days after tumor induction whereas all untreated animals died by 22 days. These results demonstrate that ADV-mediated transfer of HSV-tk to glioma cells in vivo confers sensitivity to ganciclovir, and represents a potential method of treatment of brain tumors.

Adenoviridae↗

PubMed2002

Water exchange and inflow affect the accuracy of T1-GRE blood volume measurements: implications for the evaluation of tumor angiogenesis.

The goal of this study was to determine the degree to which vascular water exchange and blood flowing into an imaging slice affect the accuracy of blood volume measurements of brain and tumor tissue when using intravascular T(1) contrast agents. The study was performed using 2D and 3D gradient-echo imaging sequences, since these are two of the most commonly used MRI methods used to evaluate tissue blood volume fraction. Computer simulations were performed and measurements made in a rat 9L gliosarcoma brain tumor model. The computer simulations demonstrate that, with either water exchange or inflow effects alone, the dependence on the physiologic and imaging parameters can be well characterized and therefore potentially offset. In the exchange only case, the parametric dependence of 3D simulations suggest that the best accuracy is achieved with high flip angles, short TR, and low blood contrast agent concentrations. However, for a 2D GRE sequence which is influenced by both water exchange and inflow, the simulations predict that the error trend as a function of the imaging and physiologic parameters is unpredictable and therefore difficult to compensate. With both 2D and 3D GRE the measured blood volume data in rat brain and tumor tissue demonstrate tissue-specific trends, which reflect differences in the considered physiologic parameters. The experimental data strongly support the computer simulations and also indicate that minimization of the physiological effects by proper selection of imaging parameters, contrast concentration, and volume calculation methods is crucial for accurate assessment of absolute blood volume fraction.

Animals↗

PubMed2001

MR-derived cerebral blood volume maps: issues regarding histological validation and assessment of tumor angiogenesis.

In an effort to develop MRI methods for the evaluation of tumor angiogenesis (new blood vessel formation), MRI-derived cerebral blood volume (CBV) information has been compared to histologic measures of microvessel density (MVD). Although MVD is a standard marker of angiogenesis, it is not a direct correlate of the volume measurements made with MRI, and therefore inappropriate for the development and validation of the MR techniques. Therefore, the goal of this study was to develop an approach by which MR measurements of CBV can be directly correlated. To this end, dynamic susceptibility contrast (DSC) MRI experiments were performed in six Fisher rats implanted with 9L gliosarcoma brain tumors. Subsequently, the circulation was perfused with a latex compound (Microfil), after which 50-microm tissue sections were analyzed for vessel count, diameter, and the fraction of area comprised of vessels. The results demonstrate that while fractional area (FA) does not provide a good measure of CBV, FA corrected for section thickness effects does. Whereas the FA in normal brain was found to be 13.03 +/- 1.83% the corrected FA, or fractional volume (FV), was 1.89 +/- 0.39%, a value in agreement with those reported in the literature for normal brain. Furthermore, while no significant difference was found between normal brain and tumor FA (P = 0.55), the difference was significant for FV (P = 0.036), as would be expected. And only with FV does a correlation with the MRI-derived CBV become apparent (r(S) = 0.74). There was strong correlation (r(s) = 0.886) between the tumor / normal blood volume ratios as estimated by each technique, although the MR-ratio (1.56 +/- 0.29) underestimated the histologic-ratio (2.35 +/- 0.75). Thus, the correlation of MRI CBV methods requires a measurement of fractional vessel area and correction of this area for section thickness effects. This new independent correlative measure should enable efficient and accurate progress in the development of MRI methods to evaluate tumor angiogenesis.

Animals↗

PubMed1991

31P NMR spectroscopy of 9L cell line in culture: differential effects of high temperature on anchored cells and spheroids.

The differential effects of high temperature on 9L rat gliosarcoma cells cultured in two distinctive forms, namely, anchored monolayer cells and multicellular spheroids, were investigated using 31P nuclear magnetic resonance spectroscopy. The critical temperatures resulting in irreversible changes in cellular energetics were found to be significantly different: 45 degrees C for anchored cells and 43 degrees C for multicellular spheroids, respectively. Phosphomonoester levels in multicellular spheroids were found to be consistently higher than those in anchored monolayer cells regardless of the temperature to which they were exposed. The study demonstrates that tissue derived from a single cell line may exhibit different metabolic properties depending on its growth pattern.

Animals↗

PubMed1993

Quantitative proton spectroscopy and histology of a canine brain tumor model.

Quantitative, single voxel proton nuclear magnetic resonance (NMR) spectroscopy and histological analysis was performed in eight dogs implanted with the transplantable canine glioma model of Wodinsky (Proc. Am. Assoc. Cancer Res. 10, 99 (1969)). Signals from choline, creatine, N-Acetyl Aspartate (NAA) and lactate were converted to molar concentration units and correlated with the quantitative analysis of histologically determined tissue types within the localized volume selected for NMR spectroscopy. In general, compared with normal brain, the lesions were associated with reductions in all metabolite concentrations, with the exception of lactate, which was increased. NAA and creatine decreases were most significantly correlated with the total lesion volume (P < 0.01), suggesting that these compounds are present in normal brain only. Changes in choline levels did not correlate strongly with any particular tissue type. Lactate was found to increase with increasing total lesion volume (P < 0.01), but not with increasing percent tumor, suggesting that it accumulates in abnormal tissue other than the tumor. The spectra reported were similar to those observed in human glioblastomas, with the exception that elevations of choline were not observed. The transplantable canine gliosarcoma system appears to be a suitable tumor model for evaluation by clinical radiological techniques such as magnetic resonance imaging (MRI) and proton NMR spectroscopy.

Animals↗

PubMed2005

Improving the reliability of obtaining tumor hemodynamic parameters in the presence of contrast agent extravasation.

A new approach to improve the reliability of dynamic susceptibility contrast MRI for the evaluation of brain tumor hemodynamics in the presence of contrast agent extravasation is described. This model-based technique simultaneously estimates the voxel-wise tumor residue function and the temporal extravascular T(1) changes following contrast agent leakage. With these estimates the model corrects the measured MRI signal, which is then used to calculate tumor hemodynamic parameters. The feasibility of this technique is demonstrated with computer simulations that cover a wide range of hemodynamic conditions and by application to eight tumor-bearing rats. The simulations demonstrate that the corrected hemodynamic parameters precisely matched the actual values with a maximum percentage error of 4.2% compared to 68.6% for the uncorrected parameters. The corrected parameters are also essentially independent of the tumor hemodynamic state and degree of contrast extravasation. Consistent with these improvements, significant differences between corrected and uncorrected parameters, calculated from a gradient-echo sequence, are shown in a rat 9L gliosarcoma model. This method combined with the hemodynamic parameters derived from GE and SE sequences shows promise as a new tool to evaluate tumor angiogenesis and its therapy.

Animals↗

PubMed1997

Tumor cell endocytosis imaging facilitates delineation of the glioma-brain interface.

We describe a method for measuring tumor cell endocytosis in vivo and provide the anatomic correlate of this tumor cell function using a superparamagnetic and histologically detectable marker for cell uptake (MION). Rats (n = 22) were intrahemispherically implanted with a thymidine kinase (TK)-positive 9L gliosarcoma cell line, where TK served as the tumor marker. Twenty-four hours after intravenous injection of 10 mg Fe/kg of MION, rat brains were removed and underwent MR imaging ex vivo at near-microscopic resolution (isotropic voxel size of 86 microm, 9.4 T) prior to histologic processing. The imaging probe accumulated within tumor cells adjacent to the hyperpermeable tumor-brain interface including microscopic deposits and along finger-like invasions of the tumor into brain, facilitating the demarcation of the true histologic tumor border in three dimensions by MR microscopy. The method has potential research and clinical implications for delineating the tumor-brain interface prior to therapy and/or for providing a rational basis for imaging nanocolloid drug delivery to solid tumors.

Animals↗

PubMed2001

GM3 as a novel growth regulator for human gliomas.

The simple ganglioside GM3 inhibits proliferation and induces apoptosis in proliferating immature rodent CNS cells. To determine whether GM3 influenced the expansion of human neural tumors the effects of GM3 treatment on primary human brain tumors were assayed. Here we demonstrate that GM3 treatment dramatically reduces cell numbers in primary cultures of high-grade human glioblastoma multiforme (GBM) tumors and the rat 9L cell gliosarcoma cell line. By contrast, GM3 treatment had little effect on cell number in cultures of normal human brain. A single injection of GM3 3 days after intracranial implantation of 9L tumor cells in a murine xenograft model system resulted in a significant increase in the symptom-free survival period of host animals. The effects of GM3 were not restricted to GBMs and 9L cells. Cultures of high-grade ependymomas, mixed gliomas, astrocytomas, oligodendrogliomas, and gangliogliomas were all susceptible to GM3 treatment. These results suggest that GM3 may have considerable value as a selectively toxic chemotherapeutic agent for human high-grade gliomas.

Animals↗

PubMed1989

Interstitial hyperthermia of experimental brain tumor using implant heating system.

New experimental system of induction hyperthermia for brain tumor using ferromagnetic implant with low Curie point has been developed. The metal implant is cylindrical needle and made of Fe-Pt alloy with low Curie point suitable for hyperthermia (50-60 degrees C). Induction coil and generator which produce maximum power of 200W and variable frequency of 100-500kHz, yielding magnetic power of 16.7Oe, have been developed. Interstitial hyperthermia was made on rat brain tumor model (T9 gliosarcoma) by this system. Significant effects of single hyperthermia (45 degrees C for 30 minutes) were observed by the extension of life span and morphological changes of the tumor.

Animals↗

PubMed1985

Vimentin and glial fibrillary acidic protein in human brain tumors.

Using the peroxidase-antiperoxidase (PAP) technique, we examined 35 primary brain tumors for expression of vimentin and GFAP. Both low-grade and high-grade astrocytomas contained vimentin-positive and GFAP-positive cells. Ependymomas also stained for both markers. In gliosarcomas, the glioblastomatous portions stained like astrocytomas, while only vimentin stain was seen in the fibrosarcomatous portions. Medulloblastomas and oligodendrogliomas were negative for both vimentin and GFAP, while meningiomas contained scattered areas of vimentin-positive cells. These results suggest that the expression of vimentin and GFAP is mostly confined to glial-derived tumors, and that vimentin can potentially be a useful marker for distinguishing undifferentiated GFAP-negative glial tumors and mesenchymal tumors from primitive neuroectodermal tumors.

Astrocytoma↗

PubMed1986

Magnetic induction hyperthermia for brain tumor using ferromagnetic implant with low Curie temperature. I. Experimental study.

Experimental study was made on magnetic induction hyperthermia for brain tumor using ferromagnetic implant with low Curie temperature. Thermoseed (implant) was made of nickel-palladium alloy, which was confirmed to produce enough heat by eddy current and also to have low Curie point between 43 degrees C-58 degrees C. Using this implant heating system, the effect of hyperthermia on normal rat brain and intracutaneously inoculated rat gliosarcoma (T9) were studied. Heat conduction from seed was twice as much in tumor tissue as in normal brain. It was also found that the intradermal brain tumors were completely diminished within 4 weeks by single local hyperthermia at 45 degrees C for 60 min.

Animals↗

PubMed1996

Intra-arterial cisplatin in malignant brain tumors: incidence and severity of otic toxicity.

Intra-arterial (IA) cisplatin is used to treat gliomas with the goal of maximizing drug concentration in the brain while minimizing systemic toxicity. The present study is based on the author's experience with IA cisplatin administration in 12 patients. The primary goal of the study was to document the extent of otic toxicity in these individuals. Hearing was tested clinically and with audiograms, before each IA cisplatin injection. Eight women and four men with a mean age of 39 1/2 years (range 22-61) were treated. Diagnoses included 7 glioblastoma multiformes, 4 anaplastic astrocytomas, and 1 gliosarcoma. Diagnosis was obtained by stereotactic biopsy in four and craniotomy for resection and debulking in eight. The mean number of IA injections per patient was 4.58 (range 3-6). The cisplatin dose was 60 mg/m2 with the average dose of cisplatin per cycle being 116 mg (range 96-130 mg). Eleven patients had the agent administered via the internal carotid and one received it by way of a vertebral artery. Nine of the twelve patients (75%) demonstrated pure tone loss, as measured by audiography, of greater than 15 dB in the higher frequencies range (> or = 3 kHz) bilaterally. One patient became deaf and two others had clinically significant hearing loss. The severity of the auditory damage increased after each administration in each of the cases with clinical abnormality. IA cisplatin may have a role in the treatment of patients with primary malignant brain tumors, but further developments to limit otic toxicity would be of value.

Adult↗

PubMed1983

Bleomycin and brain tumors. A review.

A logical inference from the recent reports indicating that malignant brain tumors are composed of a heterogeneous cell population is that combination chemotherapy will be required for effective brain tumor control. For several years we have been investigating the use of Bleomycin as an agent to be used in conjunction with radiation therapy and a nitrosourea compound. Since systemically administered Bleomycin does not cross the blood-brain-barrier and has significant toxicity when used parenterally in high doses, we have studied the use of smaller doses of Bleomycin injected directly into the brain tumor cavity. Such an intracerebral dose was more effective in prolonging survival of rats burdened with experimental 9L gliosarcomas than an intravenous dose that is 25 times as great. The combination of intracerebrally administered Bleomycin and radiation therapy was more effective than either modality alone. Furthermore, the combination of Bleomycin delivered intracerebrally and BCNU given systemically was more effective than either agent used alone. Finally, in a Phase I clinical of Bleomycin given via an Ommaya reservoir to eight patients with recurrent malignant brain tumors, we have demonstrated that individual doses of up to 7.5 units and cumulative doses of up to 255 units can be administered without significant toxicity.

Adult↗

PubMed1992

Intracerebral chemotherapy in the 9L rat brain tumor model.

We have used the 9L rat brain tumor model to search for effective chemotherapeutic approaches to the management of brain tumors. Several antineoplastic agents which have been proposed or are currently being used for human brain tumors, including 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU), bleomycin, aziridinylbenzoquinone (AZQ), cis-Platinum, and acivicin, were administered intravenously (iv), intraperitoneally (ip), or intracerebrally (ic) to rats burdened with the intracranial 9L gliosarcoma. The results confirm that BCNU is the most effective systemic agent among the chemotherapeutic agents tested as indicated by its ability to significantly increase the median survival time (MST) and life span of the tumor-burdened animals. Bleomycin is an effective agent against the intracranial 9L tumor when administered ic. While neither systemic single iv dose AZQ (0.5-2.5 mg/kg) nor multiple ip treatments (0.5-1.0 mg/kg x 5, q 6 h) were effective in prolonging the survival, single ic dose AZQ (5-50 micrograms/rat) treatment significantly increased the MST of the treated animals (P < 0.05). Systemic AZQ treatments using higher doses produced a hematological toxicity, resulting in a decrease in MST of the treated animals. Cis-Platinum, either administered ip or ic, produced only a marginal effect on survival, although acute neurologic toxicity limited the dose of cis-Platinum that could be administered ic. Acivicin, either administered ip or ic, produced no effect on the survival of treated animals. Our results suggest that local treatment with certain antineoplastic agents may be an efficient therapy in the management of brain tumors.

Animals↗

PubMed1990

A new rat brain tumor model: glioma disseminated via the cerebral spinal fluid pathways.

A rat brain tumor model has been developed with the clinical and pathological features of dissemination via the cerebral spinal fluid (CSF) pathways. A precise number of 9L gliosarcoma cells (5 x 10(2) to 5 x 10(5)) is stereotactically injected into the CSF of the lateral ventricle. The interval until the onset of neurological symptoms and then death is reproducible and dependent upon the number of cells injected. The median survival of three groups of rats receiving 5 x 10(5) cells in three different experiments was 17, 18 and 19 days respectively. For three groups receiving 5 x 10(4) cells, the median survival was 23, 24 and 25.5 days respectively and for two groups receiving 5 x 10(3) cells the median survival was 28 and 30 days respectively. The animals developed multiple tumor implants along the CSF pathways usually resulting in hydrocephalus. This tumor model was developed to simulate dissemination via CSF pathways as seen with medulloblastoma and other primitive neuroectodermal tumors of the central nervous system. It will be used to evaluate the therapeutic efficacy of intraventricularly administered anti-neoplastic drugs against small implants and malignant cells in the CSF pathways.

Animals↗

PubMed1984

Observations in studies of quantitative kinetics of tritium labelled hematoporphyrin derivatives (HpDI and HpDII) in the normal and neoplastic rat brain model.

Increasing interest has developed in the use of the photodynamic agent, Hematoporphyrin derivative (HpD) for photoradiation therapy (PRT) as adjunctive therapy of malignant glial tumors of the brain. HpD, injected systemically, is preferentially taken up and retained by neoplastic tissue. Early studies of such uptake have largely relied on gross fluorescence as evidence of tissue uptake. In this study HpD was labelled with a tritiated radioisotope (3H) in order to quantify tissue uptake in visceral and in normal and neoplastic brain tissues in a rat brain model. 3H-HpD was injected intravenously at a 10 mg/kg dose into 30 Sprague-Dawley rats (Group A) without tumors in order to clarify method. Separately, 3H-HpD of like dosage was injected into 20 Fischer-344 rats (Group B), 5 control and 15 with a 9L gliosarcoma implanted in the left anterior cerebral cortex. Post injection sacrifice occurred at 6, 24 and 48 hours. From the Sprague-Dawley group multiple somatic and cerebral specimens were assayed. Differential areas within the brain showed no significant difference in uptake. The tumor area, peritumoral margin, and distant uninvolved areas of the Fischer-344 9L rats were likewise assayed. Definite uptake of normal visceral and cerebral tissue occurred with a markedly higher uptake differential in tumor areas. Such differential was relatively consistent from trial to trial, but multiple separate values obtained in the respective study groups were often unreliabe in their reproducibility and at variance with previously reported tissue level studies. These findings implied an instability of 3H-HpD, subsequently confirmed chromatographically as contamination probably due to time related degradation and exchange. Therefore, 3H-HpD appears to inherently carry such a risk for contamination. The compound Photofrin II (HpDII) represents a chromatographic fraction of HpD (HpDI), currently considered its most photodynamically active and purest component. Tritiated Photofrin II was used for quantification. An assay was performed with 5 Fischer-344 9L brain tumor rats (Group C), sacrificed at 24 hours. Photofrin II provided results more reliably reproducible. Contamination, degradation, and exchange of 3H-Photofrin II did not appear to occur. Neoplastic brain levels of the Photofrin II isotope were higher than in the HpD studies, and highly fluorescent. Normal brain values were consistently minimal and without fluorescence. The differential tumor/brain ratio in Photofrin II was consequently much higher. The isolated active substrate of HpDI and HpDII (Photofrin II) appears to be the compound DiHematoporphyrin Ether (DHE).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1989

Lectin histochemistry of human gliomas.

Formalin-fixed and paraffin-embedded specimens of 24 human gliomas were examined histochemically with five lectins; concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin 1 (RCA-1), peanut agglutinin (PNA), and Ulex europaeus agglutinin 1 (UEA-1). Although the staining intensity with lectins was variable, tumor cells in five astrocytomas, three oligodendrogliomas, six ependymomas, and one gliosarcoma, were generally positive for Con A, WGA, and RCA-1, and negative for PNA and UEA-1, whereas those in nine glioblastomas were usually positive for Con A and WGA and negative for RCA-1 and PNA as well as UEA-1. The malignancy in neoplastic astrocytes was correlated with the decrease in binding with lectins, especially RCA-1. Blood vessels, particularly the endothelial layers, in all gliomas were stained intensely with all lectins used. Macrophages showed two staining features with lectins; stippled and granular. The former macrophages were positive for Con A, WGA, RCA-1, and PNA, and negative for UEA-1, whereas the latter macrophages were positive for all lectins used. Thus, the staining characteristics with lectins of macrophages were different from those of any glioma cells and very useful for identification of macrophages in gliomas.

Brain Neoplasms↗

PubMed1994

Cytoplasmic inclusions of astrocytic elements of glial tumors: special reference to round granulated body and eosinophilic hyaline droplets.

Round granulated body (RGB) and eosinophilic hyaline droplets (EHDs) have been described as cytoplasmic inclusions of certain astrocytic tumors. In the previous literature, however, these inclusions have been described using various terms or regarded as nosologically the same entity. Light microscopically, RGB appeared as a round discrete body filled with fine uniform granules, while EHDs demonstrated a cluster of bright eosinophilic, round objects of various size. They could be clearly distinguished even by conventional histochemical staining such as the Masson trichrome stain and the phosphotungstic acid hematoxylin preparation. Both RGB and EHDs expressed positive immunoreactions for glial fibrillary acidic protein, several lysosomal markers, and some stress-response proteins. The ultrastructural appearances of these inclusions were distinct, however, one common feature was that they consisted of aggregations of numerous membrane-bound electron-dense bodies. Thus, both inclusions appear to be produced by neoplastic astrocytes and are possibly related to the lysosomal system. We examined the presence of RGB and EHDs in 138 astrocytic tumors. Both inclusions occurred most frequently in pleomorphic xanthoastrocytomas, followed by gangliogliomas and pilocytic astrocytomas. Subependymal giant cell astrocytomas exhibited only RGBs. RGBs and EHDs were not seen in any abundance in glioblastomas, gliosarcomas, fibrillary astrocytomas, protoplasmic astrocytomas, or oligo-astrocytomas. Some glioblastomas, however, showed only EHDs in small numbers. Several anaplastic astrocytomas were associated with a large number of RGBs and/or EHDs, and they revealed only rare mitosis despite marked cellular pleomorphism. Although RGB and EHDs have different morphological features, the presence of these inclusions in abundance may represent either a degenerative change, a long-standing lesion, or an indolent growth of the astrocytic tumors.

Adolescent↗