Intra-arterial simultaneous administration of anandamide attenuates endothelin-1 induced vasospasm in rabbit basilar arteries.

BACKGROUND: Anandamide induces not only endothelium-dependent vasodilatation through cannabinoid receptors but also some endothelium- independent vasodilator effect by calcitonin gene-related peptide release through vanilloid receptors. Endothelin-1, a powerful vasoconstrictive peptide derived from endothelial cells, has been shown to be converted to its active form after cleaving by a vascular matrix metalloproteinase which is also involved in inactivation of calcitonin gene-related peptide. The purpose of this study was to investigate whether anandamide inhibits the acute vascular and morphological effects of Endothelin-1 applied intra-arterially on rabbit basilar arteries. METHOD: Fifteen albino rabbits were anaesthetised and underwent placement of a vertebral artery catheter for angiography of the basilar artery. Animals were divided, arbitrarily, into animals in which there was either intra-arterial injection of saline (Group I, n=5), Endothelin-1 (Group II, n=5) and Endothelin-1 and anandamide (Group III, n=5). The diameter of the basilar artery between the pre and post injection angiograms was measured in each of the three groups and transmission electron microscopic investigations on basilar arteries were performed. FINDINGS: Angiographic studies showed that simultaneous administration of anandamide significantly attenuated Endothelin-1 induced vasoconstriction. Furthermore, it was demonstrated that anandamide reversed the morphological changes induced by Endothelin-1 on the vessel wall. INTERPRETATION: These results indicated that anandamide overcomes the angiographic and morphological effects of intrarterially administered ET-1 induced vasospasm in rabbit basilar arteries probably by induction of CGRP related vasodilatation through vanilloid receptors and prevents the acute ET-1 induced ultrastructural vessel wall damage.

A viable residual spinal hydatid cyst cured with albendazole. Case report.

Spinal hydatid disease is a rare entity that frequently yields to severe, acute-onset neurological deficits. Although the gold standard treatment is total surgical removal of the cysts without inducing any spillage, it may not be possible to perform this in patients with multiple and fragile cysts. In such cases, the neural structures should be adequately decompressed and albendazole should be administered promptly. The authors describe the case of a 13-year-old girl who was admitted with a history of back pain and acute-onset lower-extremity weakness. Magnetic resonance imaging scans demonstrated severe spinal cord compression caused by multiple cysts involving T-4 and the mediastinum. The patient underwent surgery, and the cysts were removed, except for one cyst that was hardly exposed. Following histopathological confirmation of spinal hydatid disease, she was treated with albendazole for 1 year. One year postoperatively, the residual cyst had gradually shrunk and had almost disappeared. Although a single case is not sufficiently promising, we believe that administration of albendazole is efficient to prevent recurrences in cases in which it is not possible to obtain total removal of the cysts without inducing spillage.

Does thromboxane A2 synthase inhibitor UK-38485 prevent the vasoconstrictor effects of endothelin-1 on rabbit basilar artery?

Prevention of the production of thromboxane A2--a potent vasoconstrictor and aggregating metabolite of arachidonic acid--or infusion of the stable analogues of prostacyclin--which is another cyclo-oxygenase metabolite of arachidonic acid--has been shown to be beneficial in cerebral vasoconstriction. Endothelin-1, a peptide derived from endothelial cells, has been shown to induce a long-lasting cerebral vasoconstriction both in vivo and in vitro. The purpose of this study was to investigate the role of a novel thromboxane A2-synthase inhibitor UK 38485 on the acute vascular and morphological effects of Endothelin-1 applied intra-arterially on rabbit basilar arteries. The inguinal region of twenty four anaesthetized albino rabbits of both sexes were dissected and a catheter was inserted into the aorta via the femoral artery, for control angiography of the basilar artery and intra-arterial injection of ET-1 (0.25 ng total dose) and UK 38485 at a dose of 0.05 microgram kg-1 min-1 for 20 min or saline. Angiographic vasoconstriction quantification and morphological investigations of both vessels and brain stem either by light microscopy or transmission electron microscopy were the techniques applied for the study. We found out that, although the systemic administration of UK 38485 resulted in a potent antagonism of the acute vasoconstriction as visualized in angiographic studies, it did not affect the morphological changes induced by Endothelin-1 on the vessel wall. The results indicated that there might have been an interaction between Endothelin-1 and the prostaglandin synthesis mechanism in acute cerebral vasoconstriction.

Assessment of mortality associated with mild head injury in the pediatric age group.

Reducing mortality among accident and trauma patients requires careful attention to monitoring those regarded as being at low risk. We hospitalized almost 1600 head-injured patients in the period between 1979 and 1992 at the Neurosurgery Department of Gazi University Medical School, Ankara, Turkey. These patients were selected from among the numerous patients admitted to our emergency unit and treated with the same protocol in the same department. Among the hospitalized children, there were three patients defined as having a mild head injury on the basis of Glasgow Coma Scale scores of 15 who later had unfavorable outcomes. Clinical signs that might identify potentially endangered patients with mild injury were gathered; these included the presence of post-traumatic amnesia, somnolence, irritability, anisocoria, local evidence of trauma to the head, associated injuries, history of altered consciousness, and skull fracture. The study was designed to identify features by which patients who are in real danger can be distinguished among the many with trivial trauma that we face every day. We did not find any identifying clinical features and concluded that computed tomographic scanning is the only reliable answer. This will reduce avoidable mortality and morbidity by identifying the patients who are at higher risk than is at first evident.

Immediate ultrastructural effects of endothelin-1 on rabbit basilar artery. A comparison between immersion and perfusion fixation techniques.

In this study intra-arterial Endothelin-1 was applied to rabbit basilar arteries and morphological findings were compared between two groups who were either perfusion fixed or immersion fixed. We planned to establish the quantitative dimension of the drug-induced morphological alterations, independent of the fixation technique's effect. There was an abundance of collagenous fibres deposited among the smooth muscle cells which was not observed in control arteries and after immersion fixation. These degenerative changes are similar to the finding following subarachnoid haemorrhage. The only fixation-related difference was the fact that lamina elastica interna was not corrugated in the perfusion fixation group. It is concluded that, the observed changes in the connective tissue of the arterial wall alter the passive elastic properties and so affect the degree of the response to the vasoactive messengers.

Computed tomographic ventriculography: a clinicoradiological study of 31 cases.

We present 31 patients whose diagnoses were established by the aid of computed tomographic ventriculography. The indications for and diagnostic value of this method are reviewed.

Alteration by Iloprost of the vasospastic effects of endothelin-1 in rabbit cerebral vessels.

The reversal of endothelin-1 induced cerebral vasospasm with Iloprost was studied in the rabbit. Vasospasm in the basilar artery was evaluated by angiography; cerebral ischaemia by 'red-neurone-count' on light microscopy and morphological changes by electron microscopy. A potent antagonistic effect of Iloprost against ET-1 was observed in each of the parameters measured.

Co-incidence of Guillain-Barré syndrome and spinal cord compression in non-Hodgkin lymphoma.

Extradural, radicular and spinal cord compressions are severe neurological complications of lymphomas. Less frequently, involvement of the peripheral nervous system, polymyositis, myasthenia gravis and Guillain-Barré syndrome (GBS) occur. We report a patient with GBS along with a lymphoma of the spinal extradural space where at the beginning the features of GBS outweighed the symptomatology of the extradural spinal mass.

Head trauma and leucocytosis.

A prospective analysis of 153 cases of head trauma was conducted with respect to their white blood cell counts. A white blood cell count exceeding 20 x 10(6)/l is associated with a poor clinical grade on admission and with a 96% mortality as opposed to that of a 23% mortality for those with slightly lower or slightly above normal white blood cell count. The sensitivity for this level is a mortality of 96% while the specificity is 77%.

Tuberculoma in the suprasellar cistern: possible CT--misinterpretation as aneurysm.

A patient with multiple intracranial tuberculomas mimicking aneurysms is reported. The diagnosis was established by CT during the treatment of tuberculous meningitis. Anti-tuberculous therapy was continued until the radiological resolution of the lesions. A discussion of previous reports on the non-operative treatment of intracranial tuberculomas is included.

Computer assisted quantification of vasospasm on angiograms.

We describe a new computer-based, automated method for the assessment of in vivo cerebral vasospasm. Arterial diameter measurements were performed on post-processed digital substraction angiographic images, using "pixel" as the unit. Vasospasm which was difficult to detect by visual inspection could be measured by the "stenosis quantification" program. A computer-assisted method such as we describe might decrease the risk of subjective errors.

Evidence for the participation of vascular endothelium originated humoral factors to cerebral vasospasm.

Vascular endothelium synthesizes mediators which either cause vasorelaxation or vasoconstriction. The purpose of this study is to investigate the role of these mediators in the pathogenesis of cerebral vasospasm. An inhibitor of endothelium-derived relaxing factor is haemoglobin; endothelium removal by triton X-100 and endothelin-1 caused narrowing in the diameter of basilar artery of the rabbit. The pathological, ultrastructural investigations and computerized tomography images are in accordance with this finding. These results indicate that not only an increase in vasoconstrictor mediator level but also the lack of endothelium-derived relaxing mediators are responsible of the spasm of the basilar artery.