RU51599 is an arginine vasopressin (AVP) release inhibitor and a selective kappa opioid agonist which has a pure water diuresis effect without associated electrolyte excretion. The effect of RU51599 on brain oedema following transient forebrain ischaemia in rats was examined. Under microscopy, the visible vertebral arteries at the second vertebra could be easily electrocauterized and completely cut by microscissors to yield complete cessation of circulation of both vertebral arteries. Transient forebrain ischaemia was induced by this improved highly reproducible technique of four-vessel occlusion model. Forty-three male Wistar rats were separated into six groups; saline-treated (1 ml/kg) normal rats (n = 10), RU51599-treated (1 mg/kg) normal rats (n = 4), saline-treated (1 ml/kg) rats with complete occlusion of both vertebral arteries (n = 5), RU51599-treated (1 mg/kg) rats with complete occlusion of both vertebral arteries (n = 5), saline-treated (1 ml/kg) rats with both complete occlusion of both vertebral arteries and carotid occlusion bilaterally during 45 minutes followed by 60 minutes of reperfusion (n = 11), RU51599-treated (1 mg/kg) rats with both complete occlusion of both vertebral arteries and carotid occlusion bilaterally during 45 minutes followed by 60 minutes of reperfusion (n = 8). The brain water content was determined by the dry-wet weight method. Cerebral blood flow was monitored during ischaemia and reperfusion was performed by laser Doppler flowmetry to make sure to obtain reversible forebrain ischaemia. Effects of RU51599 on concentration of glutamate released from the hippocampal CA1 of rats subjected to 5 minutes four-vessel occlusion and 60 minutes of reperfusion were also investigated by the microdialysis method. This modified four-vessel occlusion method produced reversible forebrain ischaemia with a high level of success. Bilateral carotid occlusion followed by 60 minutes reperfusion caused a significant increase in brain water content (P < 0.01), which was significantly attenuated by RU51599 (P < 0.01). These findings indicate that the AVP-release inhibitor RU51599 reduced brain oedema following transient forebrain ischaemia in rats.

Patients with degenerative diseases of the cervical spine, such as ossification of the posterior longitudinal ligament, spondylosis, and canal stenosis, sometimes present with acute spinal cord injury caused by minor trauma. However, the relative risk of cervical cord injury with these diseases is unknown. The clinical and radiological features of 94 elderly patients with head injury, 57 men and 37 women aged from 65 to 98 years (mean 76.6 years), were retrospectively analyzed to assess the association of spinal cord injury with degenerative cervical diseases. Degenerative cervical diseases were present in 25 patients, and spinal cord injury was more common in the patients with degenerative diseases (11/25 patients) than in the patients without such diseases (3/69 patients; relative risk ＝ 10.2). The incidence of degenerative cervical diseases seems to be increasing in Japan because life expectancy has increased and the elderly are a rapidly growing part of the population. A fall while walking or cycling is a common mechanism of head injury and/or cervical cord injury in the elderly. To decrease the occurrence of cervical myelopathy, prevention by increasing social awareness and avoiding traffic accidents and falls is important.

A 62-year-old woman presented with a symptomatic arachnoid cyst of the right occipital convexity manifesting as visual disturbances and headache. She underwent craniotomy with membranectomy and fenestration to the subarachnoid space. Postoperatively, her complaints disappeared and brain magnetic resonance (MR) imaging showed cyst shrinkage. During the first 1 year after surgery, she made a good recovery without clinical symptoms or cyst enlargement. However, she complained of visual disturbances after 6 years. Brain MR imaging revealed cyst enlargement and Goldmann perimetry detected left lower quadrantanopia. The diagnosis was recurrent arachnoid cyst. A second surgical procedure was performed including membranectomy for histological examination of the cyst membrane, and an Ommaya reservoir was inserted into the cyst cavity to prevent further cyst enlargement. The histological findings were compatible with arachnoid cyst, similar to the results seen at the first surgery. She was discharged 3 weeks after the second operation with no complications, and follow up continues as an outpatient. Patients with symptomatic arachnoid cysts typically have good progress after surgery, but the present case shows that follow up should continue for at least 6 years after surgery, even if cyst volume reduction was initially favorable.

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