The changing direction of nystagmus in acute Menière's disease: pathophysiological implications.

The direction(s) and pathophysiologic basis of nystagmus during an acute attack of Menière's disease have been subject to much debate in the world literature. Clinical recordings from two patients whose nystagmus was captured near the very beginning of the acute vertiginous episode are presented. Previous clinical observations in Meniere's disease, experimental animal models concerned with initiation of peripheral nystagmus, and the phenomenon of recovery are discussed.

Expression of metalloproteinases and metalloproteinase inhibitors by fetal astrocytes and glioma cells.

Metalloproteinases have been implicated as important factors mediating the tissue migration of a variety of normal and transformed cells. The conditioned medium (CM) of fetal human astrocytes and five glioma cell lines did not degrade azocoll in suspension, but several proteolytic activities, inhibitable by 1,10-phenanthroline, were detected on sodium dodecyl sulfate-polyacrylamide gels containing gelatin. Both cell types secreted three major proteolytic species (Mr 65,000, 57,000, and 52,000).

Intradural granulocytic sarcoma presenting as a lumbar radiculopathy. Case report.

Granulocytic sarcoma usually occurs in the setting of leukemia and myeloproliferative disorders. Rarely, it can occur in isolation at various anatomical sites without hematological evidence of leukemia. The unique case of an elderly man presenting with right L2-3 radiculopathy is described.

Speculation into the etiologic role of viruses in the development of Bell's palsy and disorders of inner ear dysfunction: a case history and review of the literature.

It has long been postulated that Bell's palsy and a number of inner ear disorders may have as their basis a common underlying viral etiology. The change from one recognizable inner ear disorder into another is not unusual in the same patient and has been recognized by neurotologists. The case history of a patient who initially presented with an idiopathic facial palsy that years later developed into a spectrum of vestibular dysfunction associated with the clinical stigmata of herpes zoster is discussed.

Brain tumor epidemiology, growth, and invasion.

This article focuses on the most common primary intracranial neoplasms and the biologic descriptions of their growth and invasion. The proliferative aspects of the different primary brain tumors are discussed, along with recently discovered genetic changes. Because local invasion of primary brain tumors is a key pathologic feature of these tumors, the mechanisms known to influence cell movement are discussed.

Isolation and partial purification of growth factors with TGF-like activity from human malignant gliomas.

The effect of concentrated conditioned medium from each of eight human malignant glioma cell lines on the growth of indicator cells (normal rat kidney fibroblasts (NRK), clone 14) was determined in monolayer and in soft agar assay systems. The conditioned medium from all cell lines was mitogenic in the monolayer assay, but only SF-210, U-343 MG-A, and U-251 MG produced soluble factors that caused NRK cells to grow in soft agar. The soluble growth-promoting factors from these three cell lines were acid- and heat-stable (60 degrees C for 30 minutes) but were inactivated by trypsin (100 microns/ml) and dithiothreitol (50 microM).

Histopathologic consequences of surgical approaches to the singular nerve.

Selective sectioning of the singular nerve has proven successful in the relief of incapacitating benign positional vertigo (BPV), presumably on the histopathologic basis of posterior ampullary cupulolithiasis. Although the surgical techniques of transmeatal and the recently introduced retrosigmoid IAC approach have been well described, little has been written about the singular nerve's anatomical relationships determined histologically for each surgical approach. The anatomical relationships of the singular nerve in both the transmeatal and retrosigmoid IAC approaches are discussed.

Computed tomographic analysis of the intratemporal facial nerve and facial nerve neuromas.

High-resolution computed tomography (HRCT) has replaced multidirectional tomography in the detailed analysis of the temporal bone because of its excellent resolution of fine bony detail. Small soft-tissue masses not discernible on plain tomograms are easily seen using HRCT. Unsuspected early disease which has not caused recognizable bone erosion in also demonstrable by HRCT.

Cavernous hemangioma of the incus (an incidental finding).

The incidental discovery of a cavernous hemangioma in an apparently normal incus found during pathological examination is reported. The incus had been removed during the course of a total osseous labyrinthectomy for delayed endolymphatic hydrops (DEH), and this unexpected finding noted. Although rare, hemangiomatous involvement of the temporal bone does occur and its manifestations are discussed.

Recent perspectives in brain tumor biology and treatment.

Tumors are composed of tumor cells, normal host cells, and an ECM. Tumor growth depends on the balance between tumor cell proliferation and tumor cell loss and is significantly influenced by normal vascular, immune, and glial cells of the host. Furthermore, tumor size and growth regulation are probably influenced by components of the ECM and by edema within and surrounding the tumor.

Computer-generated three-dimensional reconstruction of the singular nerve.

Advances in computer technology have made it possible for detailed and accurate three-dimensional images of complex anatomical structures to be reconstructed from serial histologic sections. This technique is useful in visualizing the morphologic nature and relationships between many intratemporal structures. In this paper, the three-dimensional anatomy of the singular nerve was examined by means of a three-dimensional computer reconstruction.

Effect of retinoids on the proliferation, morphology and expression of glial fibrillary acidic protein of an anaplastic astrocytoma cell line.

We studied the effect of retinoids on the growth and differentiation of a cell line (U 343 MG-A) derived from a human malignant astrocytoma. Cultures treated with all-trans or 13-cis retinoic acid showed a dose-dependent inhibition of proliferation and a marked reduction in the mean cell number at the plateau phase of growth (3.5 x 10(6) vs.

The extracellular matrix of the central and peripheral nervous systems: structure and function.

The extracellular matrix (ECM) is the naturally occurring substrate upon which cells migrate, proliferate, and differentiate. The ECM functions as a biological adhesive that maintains the normal cytoarchitecture of different tissues and defines the key spatial relationships among dissimilar cell types. A loss of coordination and an alteration in the interactions between mesenchymal cells and epithelial cells separated by an ECM are thought to be fundamental steps in the development and progression of cancer.

Familial cavernous malformations. Diagnostic potential of magnetic resonance imaging.

Three patients from the same family underwent operations for neurological symptoms related to vascular lesions that proved on pathological examination to be cavernous malformations. Two of the lesions were intracranial and one was in the thoracic spine. Five other family members have also had neurological symptoms; three of these five were studied with cerebral magnetic resonance imaging and computed tomography.

The effects of human recombinant tumor necrosis factor on glioma-derived cell lines: cellular proliferation, cytotoxicity, morphological and radioreceptor studies.

To determine whether tumor necrosis factor is of potential value for the treatment of human malignant gliomas, we studied the effects of human recombinant tumor necrosis factor (rTNF-alpha) on the morphology, incorporation of tritiated thymidine, and proliferation of 5 established cell lines derived from human malignant gliomas and 3 normal human brain cell cultures. A radioreceptor analysis for rTNF-alpha was performed on all cell lines and cultures. Two of the 5 human glioma cell lines (SF-188 and U 343 MG-A) demonstrated a marked decrease (60% or less of untreated controls) in the uptake of tritiated thymidine when treated with rTNF-alpha at a concentration of 40 U/ml; rTNF-alpha at 100 U/ml had antiproliferative and cytotoxic effects on both cell lines.

Partial characterization of a soluble mitogenic factor from medulloblastoma.

To determine how medulloblastoma cells might influence the proliferation and phenotype of normal stromal cells, normal human leptomeningeal cells were treated in culture with medulloblastoma-conditioned medium; their ability to incorporate tritiated thymidine and synthesize collagen was measured. The treated leptomeningeal cells had a significantly greater uptake of tritiated thymidine and grew faster than control leptomeningeal cells. Immunofluorescence studies demonstrated a greater intensity of staining for procollagen type III in the cell layer of the treated cultures than in control cultures; diethylaminoethyl (DEAE)-cellulose chromatography of the medium showed that the treated cells synthesized predominantly type III collagen, whereas control cells synthesized type I collagen.

Growth of a medulloblastoma on normal leptomeningeal cells in culture: interaction of tumor cells and normal cells.

Well-characterized medulloblastoma cells growing in suspension were placed on top of a confluent monolayer of leptomeningeal cells. In contrast to cells placed on plastic alone, which did not grow or attach, the medulloblastoma cells attached readily to the leptomeningeal cells and grew to form enlarging spheroids. The growth of these spheroids was supported with minimal essential medium containing 10% fetal calf serum or with human cerebrospinal fluid.

Inhibition of growth and induction of differentiation in a malignant human glioma cell line by normal leptomeningeal extracellular matrix proteins.

We devised a model system to study the effects of extracellular matrix proteins on the malignant phenotype of an anaplastic glioma cell line, U 343 MG-A. Well-characterized cultures derived from normal human leptomeninges were grown to confluence and maintained for 2 weeks. The leptomeningeal cells were then removed with base and detergent, leaving behind an extracellular matrix enriched in laminin, fibronectin, type I and IV collagen, and procollagen III.

Human immunodeficiency virus can productively infect cultured human glial cells.

Six isolates of the human immunodeficiency virus (HIV) showed differences in their ability to productively infect glioma-derived cell lines and early-passage human brain cell cultures. Susceptibility to HIV infection correlated well with the expression of the astrocyte marker glial fibrillary acidic protein. The CD4 molecule was expressed on some, but not all, of the brain-derived cells; however, no correlation was observed between CD4 protein expression and susceptibility to virus infection.

Distribution of extracellular matrix proteins in primary human brain tumours: an immunohistochemical analysis.

Using immunohistochemical techniques, we localized several glycoproteins of the extracellular matrix in paraffin-embedded sections of 4 normal brain and 38 primary intracranial tumour specimens. All specimens were positively immunostained to various degrees by monoclonal antibodies to type IV collagen and procollagen III and by antisera to laminin and fibronectin. Staining was consistently most intense at sites of contact between neuroepithelial and mesenchymal or leptomeningeal elements; there was no demonstrable staining within or between neuroepithelial elements in the neuropil.