Lumbar myxopapillary ependymoma mimicking neurofibroma.

OBJECTIVE: To report a case of lumbar myxopapillary ependymoma in whom neuroradiological and surgical findings strongly suggested neurofibroma. CLINICAL PRESENTATION: The patient presented with a 2 year history of progressive monoparesthesia and monoparesia of his right leg. He reported having minimal fecal and urinary incontinence. INTERVENTION: Total resection of the tumor was achieved by total L1-L2 laminectomies. There was no attachment to the spinal cord and dura. CONCLUSION: In spite of contemporary sophisticated neuroradiological facilities, we may still have diagnostic difficulties in some spinal tumors.

Central nervous system hydatidosis in Turkey: a cooperative study and literature survey analysis of 458 cases.

OBJECT: Hydatidosis is both a medical and an economic problem in Turkey. The aim of this study was to analyze central nervous system (CNS) involvement in this disease, the related problems the disease causes, and its diagnostic and therapeutic aspects. METHODS: The authors conducted an extensive literature survey of the subject, in which papers published by Turkish authors in international and domestic journals were carefully analyzed. In addition, the authors conducted a cooperative study in which data were gathered from 47 neurosurgery departments across the country. The purpose was to determine the current status of the disease in Turkey; thus, each unit was questioned about their experience over the past 5 years. Contrary to common belief, the incidence of hydatidosis has not decreased significantly in Turkey. However, computerized tomography and magnetic resonance imaging have tremendously increased diagnostic specificity. Incidences of morbidity and mortality have improved over time, according to the results of the cooperative study, although these changes are not statistically significant. This may be attributed to experience that has been gained and to more frequent use of chemotherapy, as reflected by the cooperative study data. The two statistically significant findings of that study were expanded use of chemotherapy in the management of hydatidosis, and a higher rate of extraneural involvement in the disease. The cooperative study revealed that chemotherapy was being used more often and that there was a wider range of indications for this treatment than previously reported. The higher rate of extraneural involvement was predictable because lesions in the CNS are typically secondary in this disease. With regard to the studies' findings on cases of spinal hydatid cysts, the authors found that administration of chemotherapeutic drugs was the only statistically significant parameter (t = 3.78, p < 0.05), with the rate of chemotherapy higher in the cooperative study. CONCLUSIONS: Morbidity, mortality, and recurrence rates of hydatidosis uncovered by the cooperative study and the literature survey were not statistically significant.

No apparent role for neutrophils and neutrophil-derived myeloperoxidase in experimental subarachnoid haemorrhage and vasospasm: a preliminary study.

OBJECTIVE: The literature contains investigations and discussion of the role of neutrophils and neutrophil-derived myeloperoxidase (MPO) in inflammatory processes, local ischaemia, and ischaemia-reperfusion injury models. Our aim was to determine whether the same roles existed for neutrophils and the system involving neutrophil-derived MPO in experimental subarachnoid haemorrhage (SAH) and associated ischaemia. MATERIAL AND METHOD: Forty-eight adult New Zealand white rabbits were divided into six groups of eight. The first SAH model was applied to 16 animals. Eight of these rabbits were sacrificed after 48 hours (Group 1) and the remaining eight were killed after 96 hours (Group 2). The second SAH model applied to another 16 rabbits, which were sacrificed in two groups at the above time periods, forming Groups 3 and 4, respectively. There were two groups of 8 control animals, one group per SAH model, and these rabbits were sacrificed after 48 hours. We carried out histopathological studies using haematoxylin and eosin (H&E) stain, elastin stain, MPO immunohistochemistry, and determination of basilar artery cross-sectional diameter. We also did biochemical analysis of cerebral hemisphere and brainstem specimens, measuring tissue lipid peroxidase and MPO activity. Results were compared between the groups and with their related controls. RESULTS: In contrast to previous experimental findings in local ischaemia and ischaemia-reperfusion models, we found no histopathological or biochemical evidence to suggest a role for neutrophils and neutrophil-derived MPO in relation to subarachnoid haemorrhage and resultant vasospasm. Although we confirmed the successful induction of significant vasospasm and observed the clinical evidences of subsequent ischaemia, there was no notable accumulation of neutrophils or activity of neutrophil-derived MPO in the tissues studied. This suggests that the biological process induced by SAH follows a different pattern from that seen in local ischaemia and ischaemia-reperfusion injury.

Effect of mexiletine on lipid peroxidation and early ultrastructural findings in experimental spinal cord injury.

OBJECT: The purpose of this study was to investigate the effect of mexiletine on lipid peroxidation and on ultrastructural findings after induced spinal cord injury (SCI). The authors also compared the activity of mexiletine to that of the well-known antioxidant, methylprednisolone sodium succinate (MPSS). METHODS: Wistar rats were divided into seven groups, (Groups 1-7). Those in Groups 1 and 2 were control animals that underwent laminectomy only, after which nontraumatized spinal cord samples were obtained immediately (Group 1) and 2 hours postsurgery (Group 2). Spinal cord injury was induced in all other groups, and cord samples were obtained at 2 hours postsurgery. The rats in Group 3 underwent SCI alone; those in Group 4 received 30 mg/kg of MPSS intraperitoneally immediately after trauma was induced; and those in Groups 5, 6, and 7 received 1, 10, and 50 mg/kg of mexiletine, respectively, by intraperitoneal injection immediately after trauma was induced. Compared with the levels in control animals, lipid peroxidation was significantly elevated in rats in Groups 3 and 5, but there were no statistical differences among those in Groups 1, 2, 4, 6 and 7 in this regard. Compared with the findings in rats in Group 3, ultrastructural damage post-SCI was minor in rats in Groups 4 and 5, and there was even less damage evident in rats in Group 7. CONCLUSIONS: Analysis of these findings showed that administration of 50 mg/kg mexiletine significantly decreased the level of lipid peroxidation and protected spinal cord ultrastructure following SCI.

Attenuation of vasospasm and hemoglobin-induced constriction in the rabbit basilar artery by a novel protease inhibitor.

Calcium-activated proteolysis mediated by the protease inhibitor, calpain, has recently been implicated in the pathogenesis of cerebral vasospasm. The effect of one inhibitor of calcium-activated proteolysis, z-Leu-Phe-CONH-morpholene (zLF), on cerebrovascular constriction was examined in two experimental paradigms. In the first paradigm, the rabbit basilar artery (BA) was visualized via a transclival exposure, and its diameter was monitored using videomicroscopy. In the second experimental paradigm two intracisternal injections of autologous blood were administered to mimic a subarachnoid hemorrhage (SAH). The BA was visualized via the transclival exposure, and its luminal diameter was measured. Topical application of oxyhemoglobin (OxyHb), a known pathogenic agent in cerebral vasospasm, elicited vasoconstriction in normal animals, reducing arterial diameter to approximately 75% of resting levels. Pretreatment with zLF (100, 200, or 300 microM) attenuated vasoconstriction induced by OxyHb. In an experimental model of SAH, the diameter of the BA was reduced after the first injection of blood to approximately 67% of normal resting levels when measured 3 to 4 days later. This vasospastic response was reversed significantly by topical application of zLF (100 microM); vascular diameter was increased to approximately 84% of normal resting levels. These findings demonstrate that both acute OxyHb-induced constriction and blood-induced vasospasm are sensitive to an inhibitor of the proteolytic enzyme, calpain. Together, these observations indicate an important role for calcium-activated proteolysis in the development and maintenance of vasospasm after SAH. In addition, it may be inferred from the data that inhibitors of calcium-activated proteolysis may be useful therapeutic agents for treating this form of cerebrovascular disease.

Systemic administration of an inhibitor of endothelin-converting enzyme for attenuation of cerebral vasospasm following experimental subarachnoid hemorrhage.

The potent vasoconstrictor peptide, endothelin-1 (ET-1), has been implicated in the pathophysiology of cerebral vasospasm that occurs after subarachnoid hemorrhage (SAH). This peptide is synthesized as a large prepropeptide that requires a series of modifying steps for its activation. The last of these steps involves the proteolytic conversion of a relatively inactive propeptide, Big ET-1, to its active, 21-amino acid peptide form. The enzyme responsible for converting Big ET-1 to ET-1 is a metalloprotease called endothelin-converting enzyme (ECE). In the present study the authors examined the effects of a newly developed inhibitor of ECE on responses to ET peptides in the normal basilar artery and on pathophysiological constriction in the spastic basilar artery after SAH. In the first series of experiments the authors examined normal basilar arteries in the rabbit, which were exposed transclivally and measured on-line using videomicroscopy. Intravenous administration or topical application of an active inhibitor of ECE, CGS 26303, blocked vasoconstrictor responses to topically applied Big ET-1 but not to ET-1. In contrast, topical application of a structurally related compound that does not inhibit ECE, CGS 24592, was ineffective in blocking vasoconstriction that was elicited by a topical application of Big ET-1. These findings indicate that CGS 26303 when administered systemically is capable of blocking the conversion of Big ET-1 to ET-1 in the basilar artery without affecting the ability of the vessel to respond to ET-1. In the second series of experiments the authors examined the effects of the ECE inhibitor on cerebral vasospasm after experimental SAH. Intraperitoneal administration of CGS 26303 via osmotic minipumps significantly attenuated the delayed spastic response of the basilar artery to an intracisternal injection of autologous blood. This study provides the first evidence that systemic administration of an inhibitor of ECE is capable of preventing cerebral vasospasm after SAH. The results reinforce a growing body of evidence that ETs play a critical role in the development of spastic constriction after SAH. Moreover, the findings indicate that blocking the conversion of Big ET-1 to its active ET-1 form using CGS 26303 may represent a feasible strategy for ameliorating cerebral vasospasm.

Reversal of subarachnoid hemorrhage-induced vasoconstriction with an endothelin receptor antagonist.

Increased concentrations of the vasoconstrictor endothelin have recently been demonstrated in the cerebrospinal fluid after subarachnoid hemorrhage (SAH). This observation is consistent with the hypothesis that SAH-induced vasopasm is mediated in part by enhanced constriction due to endothelin. To investigate the issue, an endothelin receptor antagonist (ETant), cyclo(D-Asp-L-Pro-D-Val-L-Leu-D-Trp), was tested for its ability to reverse vasoconstriction after SAH. A transclival surgical approach to the basilar artery in rabbits was used, and the arterial diameter was measured continuously by videomicroscopy. Rabbits were divided randomly into six groups: 1) normal rabbits treated with 40 nmol/L ETant only; 2) normal rabbits treated with 50 mmol/L KCl, then 50 mmol/L KCl + 40 nmol/L ETant; 3) normal rabbits treated with 20 nmol/L endothelin-1 (ET-1), then 20 nmol/L ET-1 + 40 nmol/L ETant; 4) rabbits treated with 20 nmol/L ET-1 only; 5) rabbits subjected to SAH and treated with 40 nmol/L ETant; and 6) rabbits subjected to SAH and treated with artificial cerebrospinal fluid only. In normal (non-SAH) rabbits, ETant: 1) had little or no effect on resting tone; 2) did not reverse potassium-induced constrictions; and 3) substantially reversed endothelin-induced constrictions. The diameter of normal rabbit basilar arteries was 832.1 +/- 20.0 microns (mean +/- standard error). After SAH (double hemorrhage model), the mean diameter was 517.4 +/- 18.3 microns. The addition of ETant reversed this SAH-induced constriction by 70.7%.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipoma of the cerebral peduncle. Case report.

A rare case of intracranial lipoma of the cerebral peduncle was reported. Computerized tomography (CT) and magnetic resonance imaging (MRI) of this unusual tumor are described. The unique capability of direct sagittal imaging makes MRI the best procedure for evaluating the midline abnormalities. She did not have operation because she was asymptomatic. She will be checked periodically in the outpatient clinic.

Dural arteriovenous malformations in the anterior cranial fossa.

Two elderly patients with dural arteriovenous malformations in the anterior cranial fossa are reported. These patients experienced rupture of the malformations at the age of 73 and 87 years. Surgical excision of the malformation was carried out on the younger patient. In the other case megavoltage x-ray therapy was applied because radical operation was not prudent. A search of the literature provided 26 other cases of this malformation involving the anterior cranial fossa. These are the first cases of rupture of arteriovenous malformation in the anterior fossa in patients over the age of 70.