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Biomedical subjects

J R Leonard

Publications and source records attributed to J R Leonard.

52 records · Page 3Linked to original sources

Characterization of malignant gliomas and cerebrovascular disease by cerebral dynamic studies.

A technique for analysis of dynamic radionuclide studies of the cerebral circulation is described. This technique permits objective classification of observed radionuclide distribution patterns. Variation in the time-to-peak activity, and in the maximum attained activity as determined by region-of-interest analysis of cerebral hemispheric activity, was defined for a normal population. Application of these normal values permits classification of observed hemispheric radionuclide distribution patterns in anaplastic gliomas and in occlusive cerebrovascular disease. Radionuclide activity in gliomas may be normal, decreased, or increased in the region of the tumor. In cerebrovascular occlusion, decreased activity, associated with a delay in time-to-peak activity, is frequently demonstrated in the affected hemisphere.

Brain Neoplasms↗

Fine needle aspiration cytology of hemangioblastoma of the spinal cord. Report of a case with immunocytochemical and ultrastructural studies.

The cytologic features of a hemangioblastoma of the spinal cord diagnosed by an intraoperative fine needle aspiration (FNA) biopsy are reported in a 66-year-old man with a long-standing history of Charcot-Marie-Tooth disease. A dual population of delicate branching vascular channels associated with nearby coarsely vacuolated stromal cells was appreciated in the smears. Histologic, immunocytochemical and ultrastructural studies demonstrated three cell types comprising the tumor: endothelial cells, pericytes and stromal cells. Factor VIII-related antigen positivity, vimentin positivity and glial fibrillary acid protein negativity support the contention that all three types of tumor cells may arise from a common angiogenic mesenchymal ancestry. A discussion of the expected aspiration cytologic findings of other tumors of the spinal cord is also presented. FNA biopsy of suspected hemangioblastoma should be performed with utmost caution due to the possibility of extensive intraoperative bleeding, such as we experienced following sampling of this tumor.

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