Neurosurgery
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This report presents a brief overview of the medical and ethical issues involved with the procurement, preparation, safety, efficacy, and subject protection of human fetal central nervous system tissue in the context of neural transplantation. The ethical perspectives from which to view the clinical use of fetal tissue include the following: 1) that fetal tissue from elective abortions is a surgical specimen; 2) that the use of such tissue involves fetal experimentation in which the fetus is a subject; and 3) that fetal tissue is considered as a cadaveric organ specimen, similar to other organs, but with special considerations compared with adult cadaveric tissue. ⋯ Additional issues include the following: 1) the safety and quality of fetal tissue for implantation; 2) the hypothesis that "legitimization" and "redemption" (potentially positive effects of tissue donation in general) may lead to an increase in elective abortion rates; 3) the ethical issues of the validity and value of human experimentation involving neural grafting; and 4) the type of consent to be obtained and the appropriate timing. Elective abortions, however, probably will continue to be the primary source of fetal tissue for grafting for some time, until other tissue sources become available.
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Proliferation and proto-oncogene expression in 19 meningiomas of typical and atypical histology were analyzed in an attempt to understand the mechanism of growth that characterizes the neoplastic process in these tumors. Proliferation was estimated as the proliferative index by the enumeration of S-phase cells in imprints of tumor tissue exposed to bromodeoxyuridine in vitro, and the gene expression of c-myc, c-fos, c-src, c-H-ras, N-myc, acidic and basic fibroblast growth factor, insulin-like growth factors I and II, platelet-derived growth factor-alpha, and epidermal growth factor was quantified by messenger ribonucleic acid dot-blot hybridization assay. Atypical and malignant tumors had significantly higher proliferative indexes than did their nonmalignant counterparts. ⋯ Positive correlations between proliferation and proto-oncogene/growth factor expression were found for c-myc in atypical/malignant tumors and for epidermal growth factor in fibroblastic meningiomas. Deregulated expression of c-myc and c-fos common to both typical and atypical tumors suggests that these are early events in the meningioma tumor process that may disturb the control of cell differentiation and together with fibroblast growth factors are likely to endow the transformed cell with a selective growth advantage by reducing the requirement for exogenous mitogens and by providing a niche for the growth of the tumor clone. Positive correlation of c-myc levels with proliferation in atypical/malignant meningiomas implies that this is a feature of malignancy and indicates continued disruption of the negative regulation of proto-oncogene expression, perhaps by tumor suppressor gene losses, during the course of tumor progression.
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Review Case Reports
Iatrogenic cerebrospinal fluid fistula to the pleural cavity: case report and literature review.
The authors observed one case of an iatrogenic subarachnoid-pleural fistula secondary to the resection of an upper lobe carcinoma of the lung. The clinical presentation was characterized by a sudden deterioration of mental status and level of consciousness immediately after the removal of the thoracotomy chest tube. The diagnosis was substantiated by the demonstration of pneumocephalus by a computed tomographic scan of the head and by the identification of a left T5 nerve root fistula by a postmyelographic computed tomographic scan. ⋯ Operative treatment consisted of the suture ligature of the nerve root and a chest drain. The postoperative course was uneventful, and the outcome was excellent, with the only finding of sensory loss in the T5 nerve root territory. A review of the literature disclosed 11 similar cases, with some differences in the choice of the most appropriate diagnostic procedure and significant differences in the therapeutic options, which were related to the various mechanisms of injury.
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Brain retraction is required for adequate exposure during many intracranial procedures. The incidence of contusion or infarction from overzealous brain retraction is probably 10% in cranial base procedures and 5% in intracranial aneurysm procedures. The literature on brain retraction injury is reviewed, with particular attention to the use of intermittent retraction. ⋯ Recommendations for operative management of cases involving significant brain retraction are made. These recommendations optimize the following goals: anesthesia and metabolic depression, improvement in cerebral blood flow and calcium channel blockade, intraoperative monitoring, and operative exposure and retraction efficacy. Through a combination of judicious retraction, appropriate anesthetic and pharmacological management, and aggressive intraoperative monitoring, brain retraction should become a much less common source of morbidity in the future.