Biomedical subjects

J C Tonn

Publications and source records attributed to J C Tonn.

At least 91 records · Page 5Linked to original sources

PubMed1984

[Isolated liver perfusion in advanced metastases of colorectal cancers].

A special cannulation system was developed in order to completely isolate the liver in an extracorporeal circuit. Isolated hyperthermic liver perfusion at 40 degrees C with an average dosage of 1000 mg 5-FU was performed in 32 patients with liver metastases (29 colorectal carcinomas, 2 carcinoids, 1 primary hepatoma). 12 patients who had an overall 45% tumor invasion of the entire liver-volume as measured in CT-scan were treated exclusively by isolated liver perfusion. In that group median survival was 8 months and death occurred in the presence of extrahepatic metastases. Better results are achieved with isolated liver perfusion followed by intraarterial short-time infusions (Mitomycin C/5-FU) via an Implantofix catheter. Median actual survival in this group is 12 months, the longest follow-up period is 23 months.

Chemotherapy, Cancer, Regional Perfusion↗

PubMed1983

[Intra-arterial cytostatic therapy with venous filtration in a half-open system].

Hemofiltration was found to be suitable for the elimination of cytostatics out of the systemic blood circulation. By means of this technique the intensity of systemic side effects can be controlled. High drug concentrations in the tumor bearing areas along with low systemic concentrations as well as moderate systemic side effects may be achieved with intraarterial administration of chemotherapeutics combined with venous drug filtration.

Arm↗

PubMed1982

[Isolated liver perfusion with 5-fluorouracil (5-FU) in the human].

In two patients with liver metastases from colorectal cancer an isolated perfusion of the liver with 5-fluorouracil was performed. The primary tumors had been resected 5 weeks and 11 months before the perfusion treatment. By means of special cannulation system the hepatic artery and the portal vein were both arterialized. The patients recovered well after the operation. Sonographic measurements of the metastases showed colliquation areas in the tumours postoperatively.

Chemotherapy, Cancer, Regional Perfusion↗

PubMedDate not supplied

Matrix metalloproteinases and their biological function in human gliomas.

Gliomas, a type of devastating primary brain tumors, are distinct from other solid, non-neural primary neoplasms, in that they display extensive infiltrative invasive behavior but seldom metastasize to distant organs. This invasiveness into the surrounding normal brain tissue makes gliomas a major challenge for clinical intervention. Total surgical resection of gliomas is not possible, and recurrence of tumor growth is common; mean survival time is 8-12 months. Although substantial progress has been made recently toward understanding the behavior of gliomas, the mechanisms that facilitate invasion are still poorly documented. Clues to the invasion process have been ascertained through clarification of the key roles played by the extracellular matrix (ECM), cell-adhesion molecules and matrix degrading proteases. Serine proteases and metalloproteinases have been implicated in glioma tumor cell-invasion. Matrix metalloproteinases (MMPs) in particular can degrade almost all known ECM components and seem to play important roles in mediating glioblastoma tumor cell invasion. This review focuses on recent developments concerning the role of MMPs in the invasiveness of human gliomas.

Brain Neoplasms↗

PubMedDate not supplied

Heterogeneous regional expression patterns of matrix metalloproteinases in human malignant gliomas.

The aim of the study was to assess the differential intra- and intertumoral heterogeneity and patterns of matrix metalloproteinase expression in human glioblastomas in vivo. 12 glioblastoma samples were analyzed for MMP expression by semi-quantitative RT-PCR. A total of 56 samples (8 adjoining regions of 6 glioblastoma tumors) were immunohistochemically examined for the expression and regional distribution of gelatinase-A (MMP-2), gelatinase-B (MMP-9), matrilysin (MMP-7) and stromelysin-1 (MMP-3). Gelatinase-A mRNA was detected in all samples, gelatinase-B was found in numerous samples. Correspondingly, strong expression levels of both gelatinase protein was seen in immunohistochemistry. Gelatinase-A was expressed by both tumor cells and endothelium while gelatinase-B was found to be restricted to endothelial cells. Stromelysin-1 protein was not detected in any of the samples. Matrilysin was found around tumor cells of three samples from one patient only. The strong immunoreactivity seen for gelatinase-A around tumor cells and blood vessels suggests a role in both tissue degradation and tumor neoangiogenesis which is in accordance with previously published in vitro data. The marked localization of gelatinase-B to the endothelium and its presence in non-infiltrative benign lesions, however, makes a direct proteolytic role of gelatinase-B on ECM components during glioma invasion appear unlikely. Its close association with vascular structures, however, might indicate a link to neoangiogenesis. The significance of matrilysin which was only seen in tumor cells in three samples remains unclear. Stromelysin-1, though strongly expressed in cell lines, does not appear to play a role in glioblastoma tumors in vivo.

Brain Neoplasms↗

PubMedDate not supplied

Glioma cell migration is associated with glioma-induced angiogenesis in vivo.

To simultaneously assess glioma cell invasion and glioma angiogenesis in vivo by non-invasive and quantitative means, DiI-labeled C6 glioma spheroids were implanted into the dorsal skinfold chamber preparation of nude mice (n = 6). Heat-inactivated spheroids served as controls to distinguish between active and passive cell spread. Using multi-fluorescent intravital videomicroscopy, glioma cell migration was analyzed on days 1-4, 6, and 10 and spheroid vascularization was analyzed on days 3, 6, and 10 after implantation. Additionally, C6 glioma spheroids were implanted into the chronic cranial window of nude mice as an orthotopic implantation site (n = 4). In the dorsal skinfold chamber, spheroids were vascularized within 10 days and revealed a tumor-specific microvasculature. In parallel, individual glioma cells detached from the spheroid edge and migrated centrifugally demonstrating an affinity to tumor and host vessels. Glioma cells demonstrated a heterogeneous pattern of their regional migratory activity (0.2-9.6 microm/h) which correlated well with regional glioma angiogenesis (r = 0.733). Using the cranial window, glioma cells spread similarly demonstrating an affinity to the perivascular space of pial/subpial vessels with preference to the arteriolar segments. Intravital fluorescence microscopy represents a versatile technique to assess the complex relationship between glioma-driven angiogenesis and glioma cell invasion.

Animals↗

PubMedDate not supplied

Different vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors.

Astrocytoma vasculature patterns differ according to histological grade of malignancy with glioblastoma multiforme (WHO grade IV) showing most extensive endothelial proliferation. Here, we determined whether the vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors (PNETs), which can be hardly distinguished histopathologically, differ. We evaluated the spatial organization of vessels in medulloblastomas and PNETs using antibodies to von Willebrand factor (vWF) and CD34. Medulloblastoma capillaries showed slight endothelial cell hyperplasia. Microvessels sprouted from the capillaries and formed glomeruloid clusters. There were areas with chains of unopposed endothelial cells (3-10 cells). Supratentorial PNETs had highly branched capillaries with extensive endothelial cell hyperplasia. Glomeruloid arrays of microvessels extended from the capillaries. Small fragments of endothelial tubes were scattered throughout the tumor. Therefore, medulloblastomas and supratentorial PNETs showed different spatial organization of tumor vessels which can be used for differentiation of each tumor entity. These vascular patterns may reflect different tumor derived angiogenic stimuli.

Antigens, CD34↗

PubMedDate not supplied

Dissecting glioma invasion: interrelation of adhesion, migration and intercellular contacts determine the invasive phenotype.

The invasive cellular behavior of malignant gliomas is determined by receptor mediated cell-substratum contacts and cell-cell interaction as well as cellular locomotion. This study attempts to break down the complex phenomena of the invasive process into their components of attachment to neighboring cells, aggregate formation, adhesion to matrix substratum, migration and invasion into three-dimensional cellular aggregates separately analyzed in different in vitro assay systems. Using a panel of 13 glioma cell lines, adhesion to non-specifically or merosin coated surfaces was correlated to monolayer cell migration and dissemination of tumor cells from aggregates plated on these substrates. The formation kinetics of aggregates were determined and compared to the ability of these cells to rapidly attach and form mechanically stable cell-cell contacts. The motility rates in the different assay systems as well as cell-cell attachment was correlated to invasion of re-aggregated tumor cells into fetal rat brain. A tight positive correlation was found for substrate adhesion and monolayer migration. In contrast, cell-substratum contacts had little influence on dissemination of cells out of three-dimensional aggregates and no association between monolayer migration and migration of cells out of aggregates was detected. The ability of glioma cells to rapidly form aggregates was associated with enhanced migration out of aggregates. The capacity to invade fetal rat brain aggregates was correlated with the capacity to form stable intercellular adhesion as measured in a cell-cell adhesion assay. Invasion in this system was not found to be associated with migration in monolayer or with migration out of tumor aggregates. This study highlights that current in vitro assays for invasion only represent isolated aspects of the multi-cascade process which is involved in tumor cell invasion.

Animals↗

PubMedDate not supplied

Reservoir systems for intraventricular chemotherapy.

This paper describes the current techniques for intraventricular drug administration in patients with meningiosis. Advantages and disadvantages of different reservoir systems, the standard implantation procedure and more recently developed image-guided techniques are discussed. In patients with slit ventricles, the CT-based stereotactic approach is recommended for reservoir implantation.

Antineoplastic Agents↗

PubMedDate not supplied

Models for assessment of angiogenesis in gliomas.

In the last two decades, much attention has been focussed on mechanisms of glioma vascularization including the investigation of growth factors and receptors involved. Recently, these efforts resulted in various approaches for antiangiogenic treatment of experimental brain tumors. These basic science and preclinical trials need an assortment of models, which should allow investigating a variety of questions. Several objectives concerning basic endothelial cell (EC) characteristics can adequately be studied in vitro using EC monolayer assays. Three-dimensional spheroid techniques respect the more complex cell-cell and cell-environment interplay within a three-dimensional culture. To optimize the imitation of the crucial interaction of human gliomas with host endothelial cells, immunological cells and extracellular matrix, animal models are mandatory. An essential rule is to utilize an orthotopic model, since tumor-host interaction is organ specific. To avoid alloimmunogenic responses, it is desirable to use weakly or not immunogenic glioma grafts, what is best accomplished in a syngeneic model. However, since rat gliomas poorly resemble human glioma growth patterns, human glioma xenografting into immunocompromized animals should be considered. In vivo monitoring techniques like videoscopy via a cranial window or magnetic resonance imaging (MRI) allow for functional studies and improve the validity of the model employed. Finally, it is essentially to recognize the limitations of each model considered and to select that model, which seems to be most appropriate for the objectives to be investigated.

Animals↗

PubMedDate not supplied

Inhibition of Ras farnesylation by lovastatin leads to downregulation of proliferation and migration in primary cultured human glioblastoma cells.

BACKGROUND: Malignant astrocytomas are the most common primary intracranial human tumors. All therapeutic approaches are limited due to their high proliferative capacity and their ability to diffusely invade the brain. Amplification of tyrosine kinase receptors and their signaling pathways have been implicated as contributing to the molecular pathogenesis of astrocytomas, providing possible new targets for therapeutic intervention. In particular, astrocytomas, although lacking oncogenic Ras mutations, have elevated levels of activated Ras. Lovastatin, an inhibitor of the beta-hydroxy-beta-methylglutary CoA reductase (HMG-CoA-reductase), is currently used to treat patients with hypercholesterolemia. In addition, it inhibits isoprenylation of several members of the Ras superfamily of proteins and therefore has multiple cellular effects including the reduction of proliferation. MATERIALS AND METHODS: In this study, we investigated the impact of lovastatin on two human glioma cell lines and on 15 primary cell cultures established from biopsies of patients with glioblastoma multiforme (GBM,) Proliferation of glioma cell lines and primary tumor cells was determined by cell counting and by using the MTT assay. The cell morphology was analyzed by staining of actin filaments with phalloidin. Apoptosis was measured using the TUNEL assay. To investigate the influence of this drug on glioma cell motility, tumor cell migration was investigated using three dimensional spheroid disintegration assays. In addition, tumor cell invasion was analyzed with a confrontational assay between tumor spheroids and rat brain aggregates. RESULTS: Inhibition of farnesyl biosynthesis using lovastatin led to a block in Ras mediated signaling, indicated by lower MAPK activity. Consequently, tumor cell proliferation was reduced up to 80%. Lovastatin appeared to decrease glioma viability by inducing apoptosis, as indicated by morphological changes and increase of TUNEL positive cells. Lovastatin acts through isoprenoid depletion, because supplementation of the media with 50-100 microM mevalonate restored all tau eta epsilon effects. Invasion of tumor cells into brain tissue was not effected while migration was reduced beta upsilon about 30-40% in cells treated with high concentrations (> or = 100 microM) of lovastatin. This was surprising because drug treatment at lower concentrations led to a disruption of the actin cytoskeleton, as indicated by Phalloidin staining. CONCLUSION: Our data strongly suggest that inhibition of elevated Ras activity by lovastatin effectively targets the MAPK and probably other signaling pathways thus offering a pharmacological based approach for a potential treatment of human astrocytomas.

Animals↗

PubMedDate not supplied

Progesterone receptors are detectable in tumor fragment spheroids of meningiomas in vitro.

Progesterone receptors (PgR) are hardly to be found in monolayer tissue culture of meningiomas although 60-70% of native tissue specimens are PgR positive. Thus we examined whether RgR might be detectable in fragment spheroids of meningiomas in vitro. 25 meningiomas of 17 women and 8 men were investigated as native tissue, monolayer cell culture (primary passage and passage 3) and as fragment spheroid culture after 1 and 3 weeks. 18/25 native tissue samples revealed the PgR. There was no prevalence of sex or histological subtypes discernible. PgR was preserved in cell clumps of the primary passage but was completely lost when cells grew as monolayers (primary passage and passage 3). 21 meningiomas formed spheroids in vitro. In 8 out of 15 native PgR positive tumors the fragment spheroids showed PgR on cryosections after 1 and 3 weeks of culture. We conclude that PgR are preserved in a considerable amount of tumor fragment spheroids of meningiomas in contrast to monolayer culture. Thus spheroids seem to be a suitable tool to investigate progesterone/anti-progesterone effects in meningiomas in vitro.

Culture Techniques↗

PubMedDate not supplied

In vitro chemosensitivity test of malignant gliomas: clinical relevance of test results independent of adjuvant chemotherapy.

Tumor specimens of malignant human gliomas were processed in a colony forming assay (CFA, n = 70) and a metabolic test system (MTT-test, n = 49) for in-vitro chemosensitivity testing. The clinical data as well as the complete follow-up of these patients were obtained until their death or at least 2 years of survival. By means of multivariate statistical analysis we demonstrate that both test systems are not influenced by biometrical data of the patient of histopathological parameters of the tumor. According to the COX regression model the results of both assays are per se no prognostic factor when regarded independently of additional treatment. However, in 33 patients treated with either ACNU or BCNU, a prospective correlative trial clearly demonstrates a predictive value of the CFA in adjuvant chemotherapy of gliomas.

Carmustine↗

PubMedDate not supplied

Comparative amplification analysis of human glioma tissue and glioma derived fragment spheroids using reverse chromosome painting (RCP).

Tumor fragment spheroids (TFS) represent an organotypic in vitro model with preserved cytoarchitecture and matrix components of the native tumor in situ. In order to determine whether DNA amplifications within gliomas remain stable in spheroid culture, tumor fragment spheroids were established from 15 human gliomas including 14 glioblastoma and one anaplastic astrocytoma. Native tumor tissue, monolayers as well as TFS were evaluated for DNA amplification using reverse chromosome painting (RCP). A modified protocol for DNA isolation from TFS was established. Amplifications in the original tumor tissue were found on chromosomes 12q13-15, tel, 4q12-13 and 11p12-13, an amplification on 11p12-13 is reported for the first time. By RCP we could demonstrate that amplified domains on 12q13-15 and 4q12-13 in three tumors were maintained in TFS whereas the amplification on 11p12-13 could not be confirmed in TFS. In monolayer cultures, all amplifications which were detected in primary culture were lost until passage 5. The results of this first comparative study of DNA amplification in glioma by analyzing native tumor tissue and tumor fragment spheroids enables us to conclude that TFS seems to be a promising in vitro model for the study of DNA amplification under cell culture conditions.

Adult↗

PubMedDate not supplied

ECM dependent and integrin mediated tumor cell migration of human glioma and melanoma cell lines under serum-free conditions.

Collagen IV, laminin and fibronectin are constituents of the cerebral extracellular matrix (ECM), which is critical in glioma cell invasion. The aim of the present study was to evaluate the integrin dependent cell-matrix interactions of two tumors with different invasive properties under matrixfree conditions. Two human glioma (GaMG, U373) and melanoma (MV3, BLM) cell lines were grown in serum free medium. Immunofluorescence microscopy of collagen IV, laminin, and fibronectin was performed. The adhesion of monolayer cells and their migration out of multicellular spheroids was quantified for these ECM components. Integrin chains known to act as laminin receptors were blocked by specific antibodies in additional migration assays. All cell lines expressed all the ECM components under serum free conditions. Tumor cell adhesion and migration in both glioma and melanoma cell lines was increased by all the ECM components, laminin being the strongest promotor of migration. However, migration was dose dependent in gliomas, whereas melanomas revealed a dose optimum of 10 micrograms/ml laminin. Antibodies against alpha 3 integrins significantly reduced migration on laminin in all cell lines, anti-beta 1 in all cell lines except U373. Anti-alpha 2 in BLM showed a strong effect, anti-alpha 6 was a stronger inhibitor in glioma than in melanoma cells. Integrins are functionally involved in tumor cell locomotion on laminin. The blocking of laminin related integrin chains markedly reduces cell motility in a varying manner between the cell lines. Moreover, different cell lines utilize different integrins as the laminin receptor.

Cell Adhesion↗

PubMedDate not supplied

Interleukin 10 is expressed in human gliomas in vivo and increases glioma cell proliferation and motility in vitro.

Interleukin 10 (IL-10) is a cytokine with a broad spectrum of immunosuppressive activity, but itoffs role in the oncogenesis of solid tumors is still unclear. In previous experiments we have shown that IL-10 specific mRNA is produced within glial tumors in vivo. The aim of the present study was to investigate the expression of the IL-10 protein in vivo and to identify the cells producing IL-10 within the tumor tissue. Expression levels significantly increased with malignancy of the gliomas. 87.5% of grade III and IV, but only 4% of grade II tumors expressed high levels of mRNA. Elevation of IL-10 serum levels was found in 11% of low grade and in 63.6% of high grade glioma patients. In situ hybridization analysis with combined immunohistochemistry revealed that: a) IL-10 is not produced by infiltrating B- or T- lymphocytes, b) both microglia and astroglia contributed to IL-10 expression in malignant gliomas in vivo. These data suggested the functional role of IL-10 in glioma progression. Therefore, the effects of IL-10 on proliferation and migration of glioma cells were determined in vitro. Two human glioma cell lines were grown as monolayer as well as spheroids in the presence of different concentrations of IL-10. IL-10 increased cell proliferation significantly in both culture systems with a dose optimum of 25 ng/ml. Glioma cell motility was enhanced with 25 ng/ml as the optimal dose. Adding the IL-10 specific antibody reversed both effects. We conclude from our data that IL-10 is involved in the progression of glial tumors, especially in the enhancement of tumor cell proliferation and migration which promotes infiltration of the surrounding tissue.

Brain↗

PubMedDate not supplied

Transfection and dye premarking of human and rat glioma cell lines affects adhesion, migration and proliferation.

It is assumed that a cell that is transfected for any gene addition or replacement or was premarked with a cell tracker dye retains the characteristics of the original cell. The following experiments compare the original C6 rat glioma cell line with C6 cells transfected with the retroviral plasmid LacZ, and the human glioma cell lines GaMG, U373, U251, and D54 with cells stained with tracker dyes (Dil and DiO). We tested adhesion, migration and proliferation. C6 cell transfection did not affect adhesion but decreased (p < 0.05) migration. Dil staining resulted in a significant decrease (p < 0.01) in adhesion in all cell lines but U251. After DiO staining human cell lines U373 and D54 displayed a decrease in adhesion (p < 0.01) whereas U251 and GaMG cells had enhanced adhesion (p < 0.01). Dye marking of C6, GaMG and U373 cells did not alter migratory capacity. In contrast, Dil and DiO reduced migration of U251 and D54 cells (p < 0.05). There was a decrease (p < 0.01) in proliferation of the human cell lines after Dil staining. Transfection or membrane dyes can alter basic cell characteristics. The assumption that a transfected or dye marked cell is the same as the original cell but with an additional gene or the presence of a dye in the membrane is untenable.

Animals↗

PubMedDate not supplied

Guanidinobenzoatase and UPA in high-grade human astrocytomas and after xenografting cell suspensions into the rat cerebral cortex: proteases for metastasis and disease progression.

BACKGROUND: Invasion and metastasis is aided by the secretion of guanidinobenzoatase, that cleaves the link peptide to fibronectin, and urokinase plasminogen activator (uPA), which initiates a molecular cascade to activate plasmin and collagenases. This process permits malignant cell migration through the extracellular matrix. MATERIALS: Original human astrocytomas were examined for guanidinobenzoatase and uPA. Suspensions of high-grade human astrocytomas were xenografted into pockets in host cerebral cortex for 1-7 days. RESULTS: A class of guanidinobenzoatase positive cells was observed in the original human astrocytomas and in tumor masses formed in the implantation pocket and around blood vessels. Secondary foci containing guanidinobenzoatase positive cells formed around blood vessels and individual positive astrocytoma cells migrated on the glia limitans along parallel and intersecting nerve fiber fascicles and the corpus callosum. uPA and GFAP were colocalized with guanidinobenzoatase. CONCLUSION: The high-grade astrocytomas reestablish themselves and maintain their characteristics as a tissue although grafted as individual cells.

Animals↗