Edmund H. Frank

Expression of class II major histocompatibility antigens on reactive astrocytes and endothelial cells within the gliosis surrounding metastases and abscesses

To pursue the hypothesis that astrocytes may function as immunoregulatory cells, astrocytes within the reactive gliosis surrounding metastases and abscesses were examined for the expression of the class II major histocompatibility antigen HLA-DR. The tissue was analysed using single- and double-label avidin-biotin immunoperoxidase techniques employing monoclonal antibodies for HLA-DR (D1-12), macrophages (anti-Fc), T lymphocytes (2D3), glial fibrillary acidic protein (GFAP) and GFAP antiserum. Macrophages, astrocytes and T lymphocytes were present. The double label demonstrated HLA-DR on a large number of astrocytes. Taken together with evidence that astrocytes can release interleukin-1 and can present an antigen to lymphocytes, the finding of HLA-DR on these astrocytes supports their possible involvement in the cellular immune response.

Identification of motoneurons innervating the tensor tympani and tensor veli palatini muscles in the cat

The somatotopic arrangement of the motoneurons associated with the two non-masticatory muscles innervated by the trigeminal motor nerve, tensor tympani (TT) and tensor veli palatini (TVP), was determined in the cat using retrograde transport of horseradish peroxidase. The motoneurons of the TT are distinct and separate, ventral and ventral-lateral to the rostral two-thirds of the trigeminal motor nucleus. The cells are smaller than those of the motor nucleus and constitute a parvocellular division. Based on functional and morphological criteria, TT motoneurons may be considered as an accessory trigeminal nucleus. The somatotopic arrangement of TVP motoneurons has been described for the first time. These motoneurons are located in the rostral two-thirds of the ventromedial division of the cat trigeminal motor nucleus. The location of motoneurons associated with TT and TVP does not fit the parcellation of the cat trigeminal motor nucleus as described by previous investigators. The motoneurons of these muscles can now be assigned to areas either within (TVP) or adjacent to (TT) the rostral two-thirds of the motor nucleus.

Bilateral epidural hematomas

Sixty-four cases of bilateral epidural hematomas were reviewed. The factors of patient age, direction of injuring forces, location of hematomas, presence of associated skull fracture, and time interval between injury and onset of signs and symptoms were analyzed. The results of this analysis show that bilateral epidural hematomas may develop slowly indicate that they occur with traumatic forces predominantly oriented in the anteroposterior direction, have fewer overlying fractures associated with them than unilateral epidural hematomas, and commonly contain venous blood. the differences between unilateral and bilateral epidural hematomas in direction of injuring forces, frequency of overlying skull fracture, and type of hemorrhage suggests that varying mechanisms may be responsible for production of these hematomas. Serial angiograms and CT scans have shown delayed accumulation of blood in bilateral epidural hematomas. This finding challenges the theory that epidural hematomas develop within minutes following injury.

Basilar impression and platybasia in osteogenesis imperfecta tarda

Osteogenesis imperfecta, a rare, genetically transmitted disorder of bone, is known to be associated with the development of basilar impression and platybasia. These deformities of the base of the skull may cause neurosurgical abnormalities secondary to compression of the brainstem and hydrocephalus. The case is presented of a young boy with a family history of osteogenesis imperfecta tarda who suffered respiratory arrest during hospitalization. Cranial nerves and pyramidal tract signs were demonstrated. Roentgenograms showed severe basilar impression and hydrocephalus. Decompression of the brainstem and shunting were performed with improvement in the patients neurological status. This case represents a rare by significant central nervous system complication of osteogenesis imperfecta. Early recognition and implementation of aggressive treatment are important if irreversible neurological deficits are to be avoided.

Cytokeratin provides a specific marker for human arachnoid cells grown in vitro

Cells from cranial and spinal arachnoid membranes of humans were grown in culture. Their growth characteristics, morphology and details of their cytoskeletal composition are described. Arachnoid membranes, obtained at autopsy, were finely minced and incubated in tissue culture medium. Monolayers of cells of homogeneous morphology grew from these tissue fragments. The cells were flat and polygonal. They divided slowly to form nonoverlapping monolayers of low cell density. Electron microscopic examination of cultured arachnoid cells revealed numerous desmosome-like tight junctions and abundant intermediate filaments (tonofilaments). Both morphological features are characteristic of arachnoid cells in situ, but not of cells in the fibroblast-rich dura mater. Immunofluorescence microscopy with monoclonal antibodies demonstrated cytokeratin in the cytoplasm of primary cultures of arachnoid cells. Thus we demonstrated that these cultured cells retained certain of the specific differentiated properties of arachnoid cells in situ and that they are not fibroblasts (which lack tight junctions and cytokeratins). To our knowledge, there have been no previous reports of in vitro growth of arachnoid cells. This in vitro model should be useful in studying the response of arachnoid cells to a variety of substances thought to be involved in the chronic inflammatory condition of the meninges known as arachnoiditis.

Chondromyxoid fibroma of the petrous-sphenoid junction

A case of primary chondromyxoid fibroma of the petrous and sphenoid bones extending into the posterior clinoid process, sella, and cavernous sinus in a 26-year-old man is reported. The presence of this tumor was heralded solely by the progressive paresis of the abducens nerve. The occurrence of this tumor is exceedingly rare, and to our knowledge, this is the first report of a primary chondromyxoid fibroma in the parasellar region. The natural history of this tumor, its pathologic diagnosis, and its treatment will be discussed with reference to this unusual case.

The prolonged Q-T syndrome presenting as a focal neurological lesion

A patient with a prolonged electrocardiographic Q-T interval suddenly developed left hemiplegia after an episode of ventricular fibrillation. A CT scan showed a cerebral infarction in the right internal capsule. The prolonged Q-T interval, by virtue of its association with cardiac arrhythmias, may cause cerebral hypoperfusion that commonly results in generalized neurological deficits. The lack of evidence for embolization in this patient suggests that decreased cerebral perfusion was responsible for the genesis of her neurological signs and symptoms. The prolonged Q-T interval is an easily overlooked cardiac abnormality that must be considered in a patient who exhibits a focal neurological deficit.