A pilot investigation of poloxamer 407 for the prevention of leptomeningeal adhesions in the rabbit.

Leptomeningeal adhesion formation frequently complicates operations and diseases of the central nervous system. Chronic adhesive arachnoiditis may follow intraspinal surgery for disc, tumor, and closure of myelomeningocele, eventually producing pain and declining neurological status of the patient. Reoperation for scar removal is seldom successful as the arachnoidal adhesions reform. Poloxamer 407 (P407) has been shown to reduce postoperative peritoneal adhesion formation in rats and golden hamsters. In a rabbit model, we investigated the potential of P407 to prevent the production of arachnoidal adhesions and nerve root scarring following laminectomy and surgical meningeal injury. The lumbar spinal roots of 8 New Zealand white rabbits were surgically isolated under magnification. One root sleeve axilla was opened and immediately closed with 10-0 suture (control site) and a second root sleeve axilla was opened, P407 injected, and closed with 10-0 suture (treatment site). Five of 7 rabbits treated with P407 and followed for 7-42 days showed no arachnoidal adhesions at the level of the nerve root. Four New Zealand white rabbits had the lamina removed, and the dura over the spinal cord was opened at two sites separated by one to two lumbar segments. At one site P407 was inserted beneath the dura following durotomy, and the other site was opened in a similar fashion and immediately closed without the insertion of P407. There was a 50% reduction in leptomeningeal adhesion formation with the use of P407. P407 may be useful in neurosurgery for the prevention of arachnoidal adhesions.

Hemangioblastoma of the third ventricle.

A case of intraventricular hemangioblastoma not associated with von Hippel-Lindau disease is presented. Only one other case of intraventricular hemangioblastoma has been reported. The literature on supratentorial hemangioblastomas is reviewed, and the problems of histological identification of such lesions are discussed.

Primary infiltrating signet ring carcinoma of the eyelids.

A 61-year old man presented with a five-year history of a swelling initially developing in his right lower lid that progressed to involve the lateral canthal skin and eventually the upper lid and anterior orbit. He was discovered to have an infiltrating, poorly differentiated, mucin-producing carcinoma. Systemic work-up failed to disclose a visceral malignancy, and it was concluded that his tumor was primary in the lids, arising from an adnexal sweat gland. Three other reports in the literature also share almost identical clinical and pathologic features, in that all of the earlier reports dealt with middle-aged or elderly men who had diffusely indurated lids. Histopathologically, the tumor cells grow diffusely in a sclerotic stroma, and resemble the "histiocytoid" variant of metastatic breast carcinoma to the lids in women. Ultrastructural studies in our case point toward an apocrine origin, although earlier authors have favored an eccrine origin. Despite its indolent clinical course, the tumor is capable of producing regional and distant metastases on long-term follow-up. Complete local excision, possibly necessitating radical surgery, is probably the preferred method of treatment, but local radiotherapy may have a beneficial effect in retarding spread of the disease.

Cytomegalovirus retinitis in a young homosexual male with acquired immunodeficiency.

A case is reported of histopathologically documented CMV retinitis. It is part of a recently appreciated syndrome in young homosexual men, in which cellular immune deficiency has been documented and in which CMV infection may play a role. This case demonstrates that CMV retinitis is not excluded by negative CMV serology or cultures.

Cell rigidity: Effect on concanavalin A-mediated agglutinability of fibroblasts after fixation.

A quantitative hemadsorption assay distinguishes the effects of membrane fixation on concanavalin A-mediated agglutinability of fixed cells with unfixed cells. We observed undiminished adherence of unfixed erythrocytes to glutaraldehyde-fixed normal and virus-transformed hamster fibroblasts coated with concanavalin A. Fixation of the erythrocytes abolished agglutination with fixed fibroblasts. The agglutinability of fixed cells is more likely related to increased cell rigidity than to decreased membrane fluidity.