Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two cases of stereotactically induced and spontaneously metastasizing neoplasms in the rat and the cat brain are reported. In the rat, a malignant Schwannoma derived from initially supratentorially implanted RN6 cells developed a second tumor in the posterior cranial fossa. In the cat, a highly malignant polymorphous anaplastic glioma induced by implantation of cloned rat glioma cells (F98) into the left internal capsule developed small tumor cell nests along the ependyma of the ipsilateral ventricle. In precontrast magnetic resonance imaging (MRI) of both cases, the primary tumor was detectable only by a very weak hypointensity and through a shift of the midline. No metastases were apparent. Application of the metallated paramagnetic porphyrin derivative manganese(III) tetraphenylporphine sulfonate (MnTPPS) resulted in a remarkable contrast enhancement between tumoral and normal tissue, which was evident not only in the primary tumor but also in the small metastases. These observations demonstrate for the first time that MnTPPS is an efficient MRI contrast agent for the detection of metastases from primary brain neoplasms and, in consequence, support the hypothesis of its selective binding to tumor cells.
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PMID:Identification of intracranial liqor metastases of experimental stereotactically implanted brain tumors by the tumor-selective MRI contrast agent MnTPPS. 150 24

The subcapsular renal transplantation tumor model was explored to standardize the growth of rat RN6 neurinoma and RG2 glioma nitrosourea-induced clonal cell lines in syngeneic and allogeneic systems. Growth of RN6 and RG2 tumor spheroids was compared with that of solid subcutaneous tumor pieces transplanted under the renal capsule. Two morphometrical methods were applied to evaluate growth rates. Tumor specimens were examined histologically with regard to their morphology, extent of immune reactions, and development of tumor necroses. The take rate was 98%. In the syngeneic system linear progressive tumor growth was found, while in preirradiated allogeneic rats this was only the case up to 21 to 25 days post transplantation (p.t.). Strong rejection reactions in the allogeneic RN6 tumors were noted from 4 to 7 days p.t. resulting in total tumor rejection after 10 to 14 days. Both kinds of tumors, especially in the first days of growth, were characterized by strong desmoplastic reaction with rich reticulin fiber formation. However, after 10 days, in the center of RG2 subcapsular renal tumors (SRT) this kind of reaction was found only in the vicinity of tumor vessels, while RN6 SRT demonstrated reticulin fibers around tumor cells in all cases studied. The transplantation experiments revealed that the malignant RN6 and RG2 spheroids represent a suitable tool to study three-dimensional early tumor growth in both in vivo and in vitro cultures. The model of spheroid transplantation under the renal capsule is simple to handle and well reproducible. Compared with subcutaneous tumors the SRT model has advantages in early stages of tumor growth because the tumors are clearly visible grossly and can be easily submitted to adequate morphometry, indicating that this model may be suitable for experimental chemotherapy and radiotherapy studies.
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PMID:Subcapsular renal transplantation of neurogenic tumors and tumor spheroids. A comparative study of RN6 and RG2 tumor clones after syngeneic and allogeneic transplantation. 373 66

Diffusion-weighted magnetic resonance imaging was used for the description of experimental brain tumors in rat. To validate this approach, diffusion-weighted images (DWI) were compared with native T1- and T2-weighted images, and with T1-weighted images following contrast enhancement with the tumor-specific contrast agent manganese (III) tetraphenylporphine sulfonate (MnTPPS). Three tumor types were studied: F98 glioma, RN6 Schwannoma, and E376 neuroblastoma. On heavily diffusion-weighted images, all three tumor types as well as the peritumoral edema were clearly hypointense with respect to the intact brain tissue. T2-weighted images presented mainly peritumoral edema as hyperintense region. A clear demarcation of the tumor was possible only on T1-weighted images after contrast enhancement with MnTPPS. The difference in signal intensity between tumor and homotopic regions in the contralateral hemisphere was comparable in DWIs and in contrast-enhanced T1-weighted images. Spatial comparison of depicted lesion areas in all three imaging modalities indicated that hypointense region on DWI represents both tumor and edema but does not permit their spatial differentiation.
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PMID:Diffusion-weighted MR imaging of experimental brain tumors in rats. 760 Jan 72

The detection of brain tumors using standard techniques of qualitative, relaxation-weighted magnetic resonance imaging (MRI) requires the application of contrast agents. We investigated whether or not it is possible to use diffusion-weighted MRI to localize tumors without contrast enhancement. Three different experimental rat brain tumors were studied: F98 glioma, RN6 Schwannoma and E376 neuroblastoma. We found a marked hypointensity in the region of the tumor and edema in heavily diffusion-weighted images, which corresponded well with the histological presentation. Quantitative maps of the apparent diffusion coefficient (ADC) allowed a better localization of the tumor than that obtained by regional presentation of T2 times, particularly under conditions in which peritumoral edema was absent. The ADC differences of the three tumor types were statistically not significant. Based upon regions-of-interest evaluations, tumor could be distinguished from peritumoral edema and normal brain tissue. However, a sharp demarcation between tumor and peritumoral edema was not possible, and this is attributed to a similar enlargement of interstitial space. It was concluded that diffusion-weighted MRI possesses a high potential for the detection of brain tumors but does not allow precise demarcation of the tumor border.
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PMID:Quantitative diffusion MR imaging of cerebral tumor and edema. 797 85

T1 and T2 were determined simultaneously in vivo at 4.7 T in implanted rat brain tumors. Three different tumor cell lines were implanted in the right caudate nucleus: the F98 glioma, the E367 neuroblastoma, and the RN6 schwannoma. Their T1 and T2 values (mean +/- standard deviation [msec]), respectively, were 1,312 +/- 107 and 89 +/- 3 (glioma), 1,284 +/- 86 and 87 +/- 7 (neuroblastoma), and 1,338 +/- 85 and 86 +/- 9 (schwannoma). The T1 values (msec) of normal brain and muscle were 1,090 +/- 59 and 1,139 +/- 77, respectively, and the T2 values (msec) were 76 +/- 3 and 36 +/- 2, respectively. After injection of the contrast agent manganese (III) tetraphenylporphine sulfonate (TPPS) the T1 of all three tumors decreased by 30% and the T2 by 10%, whereas no such change in relaxivity was noted in normal brain. As a result, strong contrast enhancement of the three tumor types was seen on T1-weighted images. The tumor was clearly delineated and correlated with findings at histologic examination. This tumor enhancement was followed up for 4 days with quantitative relaxation time measurements, and the strong, selective reduction in T1 for all three tumor types after Mn-TPPS injection was preserved over the entire observation period.
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PMID:In vivo relaxometry of three brain tumors in the rat: effect of Mn-TPPS, a tumor-selective contrast agent. 842 1

The potential of quantitative parameter images of the relaxation times T1 and T2, the proton density rho and the apparent diffusion coefficient (ADC) to characterize three different experimental rat brain tumors (F98 glioma, RN6 Schwannoma, and E376 neuroblastoma) was studied. All parameter values, as determined in histologically confirmed regions of interest (ROI), were higher in edema than in tumor, which in turn were elevated with respect to normal brain. ROI values of ADC and T2 delivered statistically significant (P < 0.01) differentiation between tumor and edema. Multidimensional parameter combinations improved differentiation between different tissues. However, the three tumor types could not be differentiated. All parameter maps allowed the identification of the whole tumor-edema area. On T2 images, edema could be identified best, whereas the tumor itself was hardly visualized. In many cases, tumor presentation using T1 maps corresponded best with histology, nevertheless suffering from a poor tumor-edema differentiation.
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PMID:High resolution quantitative relaxation and diffusion MRI of three different experimental brain tumors in rat. 859 10