Acta neurochirurgica
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Acta neurochirurgica · Jan 2000
Systemic administration of mexiletine for attenuation of cerebral vasospasm following experimental subarachnoid haemorrhage.
Mexiletine is a class Ib drug that is widely used to treat ventricular arrhythmias. This compound is mainly known as a sodium channel blocker, but studies have demonstrated that it can also activate ATP-sensitive K+ channels and block Ca2+ channels. Recent in vitro data from experiments on liposomes indicate that mexiletine is also a potent antioxidant. ⋯ Considerable vasorelaxation was seen in the prevention study, in which average arterial cross-sectional areas were reduced by only 17.86% and 39.29% in the mexiletine 80- and 20-mg/kg/day groups, respectively, compared with controls (p < 0.001). Compared with controls, average arterial cross-sectional areas were reduced by 53.58% and 64.29% in the mexiletine 80- and 20-mg/kg/day reversal groups, respectively. Our findings indicate that mexiletine induces potent relaxation in cerebrovascular arteries contracted with various agents, and that it prevents and partially reverses SAH-induced vasoconstriction.
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Acta neurochirurgica · Jan 2000
Comparative StudySystemic and cerebral haemodynamics during craniotomy under mild hypothermia in patients with acute subarachnoid haemorrhage.
Mild hypothermia provides cerebral protection against ischaemic insults in various animal models. We compared systemic and cerebral oxygenation between mild hypothermic and normothermic management in 60 patients with acute subarachnoid haemorrhage who underwent clipping of cerebral aneurysms. ⋯ The balance between oxygen supply and demand systemically and in the brain may worsen during aneurysm surgery for patients with acute subarachnoid haemorrhage under mild hypothermia. Oxygenation of the brain and the whole body should be monitored closely during this surgery, and adequate circulatory assistance is recommended under mild hypothermia.
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Acta neurochirurgica · Jan 2000
Lumbar intervertebral disc herniation following experimental intradiscal pressure increase.
An experimental biomechanical model of overload and rupture of the annulus fibrosus (AF) and lumbar disc herniation was achieved by increasing intradiscal pressure while keeping disc height constant in 69 motion segments at the L4-L5 level excised from cadaveric spines. The experiments were made on 53 specimens in neutral posture and on 16 specimens in flexion posture. ⋯ The herniated lumbar intervertebral disc model by intradiscal pressure increase makes possible these assertions: * The correlation between the degree of AF degeneration and the RIP is significant: the maximum RIP corresponds to a non-degenerated AF and the less RIP can tear only a degenerated AF; so disc herniation only occurs to discs with torn AF. * AF breaking is more often paramedian, left or right. The place of AF breaking was paramedian in 70.3% cases, median in 9.45% cases and posterolateral in 20.25% cases.
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Acta neurochirurgica · Jan 2000
Spinal subdural and epidural haematomas: diagnostic and therapeutic aspects in acute and subacute cases.
The diagnosis of spontaneous spinal haematomas mainly depends on magnetic resonance imaging. This study evaluates the MRI characteristics of spinal epidural and subdural haematomas. The results were correlated with medical history, coagulation abnormalities and therapeutic outcome to provide guidelines for early diagnosis and treatment of spinal epidural and subdural hematomas. ⋯ Spontaneous spinal hematomas are frequently located in the thoracic spine. Subdural spinal haemorrhage is more frequent than epidural. Epidural haemorrhage is frequently located dorsal to the spinal cord because of the tight fixation of the dura to the vertebral bodies.
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Acta neurochirurgica · Jan 2000
Time-course of blood-brain barrier permeability changes after experimental subarachnoid haemorrhage.
An increase in blood-brain barrier (BBB) permeability after subarachnoid haemorrhage (SAH) has been described in humans and has been correlated with delayed cerebral ischemia and poor clinical outcome. Few studies examined in the laboratory the relationship between SAH and BBB, with contrasting results due to limitations in experimental probes adopted and in timing of observation. The aim of this study was to quantify the time-course of BBB changes after experimental SAH. ⋯ As compared to sham-operated controls, SAH determined a significant BBB permeability change beginning 36 hours after SAH, peaking at 48 hours, and normalizing on day 3. This study provides a quantitative description of the temporal progression and recovery of BBB dysfunction after SAH. These results have implications for the management of aneurysm patients and for assessing the rationale and the therapeutic window of new pharmacological approaches.