Naltrexone for treatment of impaired awareness of hypoglycemia in type 1 diabetes: A randomized clinical trial

AIMS

Impaired awareness of hypoglycemia (IAH) is a limiting factor in the treatment of type 1 diabetes (T1D) and is a challenging condition to reverse. The objective of this study was to test the hypothesis that naltrexone therapy in subjects with T1D and IAH will improve counterregulatory hormone response and recognition of hypoglycemia symptoms during hypoglycemia.

METHODS

We performed a pilot randomized double blind trial of 4weeks of naltrexone therapy (n=10) or placebo (n=12) given orally in subjects with T1D and IAH. Outcome measures included hypoglycemia symptom scores, counterregulatory hormone levels and thalamic activation as measured by cerebral blood flow using MRI during experimental hypoglycemia in all subjects before and after 4weeks of intervention.

RESULTS

After 4weeks of therapy with naltrexone or placebo, no significant differences in response to hypoglycemia were seen in any outcomes of interest within each group.

CONCLUSIONS

In this small study, short-term treatment with naltrexone did not improve recognition of hypoglycemia symptoms or counterregulatory hormone response during experimental hypoglycemia in subjects with T1D and IAH. Whether this lack of effect is related to the small sample size or due to the dose, the advanced stage of study population or the drug itself should be the subject of future investigation.

Orgasmic headache and middle cerebral artery dissection

A patient with a 20 year history of primary orgasmic headache is described who, after suffering an unusually severe episode of orgasmic headache was found to have a middle cerebral artery dissection. This unusual association of primary and secondary orgasmic headache emphasises the need for a thorough diagnostic examination when the orgasmic headache differs from that of previous episodes or is associated with neurological symptoms.

Milrinone for the treatment of cerebral vasospasm after subarachnoid hemorrhage: report of seven cases

OBJECTIVE

The intra-arterial infusion of papaverine has been used for dilation of spastic cerebral vessels after aneurysmal subarachnoid hemorrhage, although its efficacy is controversial. Milrinone is an inotropic drug that dilates vessels by phosphodiesterase inhibition in a mechanism similar to that of papaverine. We examined the effects of intra-arterial and subsequent intravenous administration of milrinone on patients with symptomatic cerebral vasospasm.

METHODS

Seven patients with cerebral vasospasm were enrolled in this study. Milrinone was delivered intra-arterially via catheter at a rate of 0.25 mg/min. The total delivered dose was between 2.5 and 15 mg. Radiological measurement of the middle cerebral artery diameter and cerebral blood flow was carried out before and after arterial infusion. Intravenous treatment followed at 0.50 or 0.75 microg/kg/min for up to 2 weeks from the onset of subarachnoid hemorrhage.

RESULTS

Dilation of the vasospastic vessels occurred in all patients. The rate of cerebral blood flow was calculated in six patients and was increased in all. Subsequent intravenous infusion was effective in preventing a recurrence of symptomatic vasospasm in four of the seven patients.

CONCLUSION

It is suggested that milrinone was effective and safe for the treatment of cerebral vasospasm after subarachnoid hemorrhage in the patients in this series. Intra-arterial infusion with adjunctive intravenous infusion holds promise as a clinically advantageous treatment regimen.

Effects of mitogen-activated protein kinase inhibitors on cerebral vasospasm in a double-hemorrhage model in dogs

OBJECT

Mitogen-activated protein kinase (MAPK) may be involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage. This study was conducted to investigate the ability of the MAPK inhibitors PD-98059 and U-0126 to reverse vasospasm in a double-hemorrhage model in dogs.

METHODS

Twenty-two adult mongrel dogs of either sex, each weighing 18 to 24 kg, were divided randomly into four groups: control SAH (four dogs), vehicle- (dimethyl sulfoxide, six dogs), PD-98059- (six dogs), and U-0126-treated groups (six dogs). The double-hemorrhage model was created by an autologous blood injection into the cisterna magna on Days 0 and 2. An intracisternal injection of MAPK inhibitors was administered once per day on Days 3 through 6. Cerebral angiography was performed on Days 0 and 7 before the animals were killed. Western blot analysis was used to study the effects of hemorrhage and drug treatment on the MAPK immunoprecipitation. Severe vasospasm developed in the dogs in the control and vehicle-treated groups (basilar artery [BA] diameter reduction 46.6 +/- 5.5% and 49.3 +/- 4.6%, respectively). In the PD-98059-treated group, most of the dogs developed mild vasospasm (18.9 +/- 6.2%). In the U-0126-treated group, severe vasospasm was observed despite treatment (39.6 +/- 6.4%). The PD-98059 but not the U-0126 abolished MAPK immunoprecipitation in the spastic BAs. However, treatment with either PD-98059 or U-0126 improved the clinical scores of the dogs.

CONCLUSIONS

The present study is the first in which the effects of MAPK inhibitors on vasospasm have been investigated in vivo. The authors demonstrate that MAPK may play a role in vasospasm and that PD-98059 is a potential candidate for the treatment of cerebral vasospasm.

Reversal of severe cerebral vasospasm in three patients after aneurysmal subarachnoid hemorrhage: initial observations regarding the use of intraventricular sodium nitroprusside in humans

OBJECTIVE AND IMPORTANCE

The chronic delayed type of cerebral vasoconstriction that occurs after aneurysmal subarachnoid hemorrhage (SAH) is now the most important cause of mortality and neurological morbidity for patients who initially survive the rupture of cerebral aneurysms. Although intravascular volume expansion and cardiac performance enhancement have had a profound impact on the treatment of the chronic delayed type of cerebral vasoconstriction, this form of treatment is not tolerated by all patients and is unhelpful in some. A more specific and more reliable treatment for this condition has not been previously reported. Previous work in an animal model has demonstrated the efficacy of nitric oxide-donating compounds in reversing severe cerebral vasoconstriction when delivered to the adventitial side of the blood vessel. A clinical study was initiated after receiving approval from the United States Food and Drug Administration and the institutional review board.

CLINICAL PRESENTATION

Three cases of prompt and substantial reversal of medically refractory vasospasm occurring after aneurysmal SAH in humans using an intrathecally administered nitric oxide donor and clinical, angiographic, and ultrasonographic documentation are presented. All patients developed severe vasospasm refractory to medical treatment 5 to 12 days after sustaining aneurysmal SAH. All patients manifested stupor of new onset (Glasgow Coma Scale score of 7) and new focal neurological deficit (hemiplegia). The condition was angiographically demonstrated in all cases.

INTERVENTION

The patients were treated with intrathecally administered sodium nitroprusside, which caused the reversal of vasospasm, which was documented by angiography and transcranial Doppler ultrasonography up to 54 hours later and also by dramatic clinical improvement. Complications related to intracranial pressure elevation, changes in vital signs, and hemodynamic parameters were not observed during or after the procedures. Radiographic evidence of the reversal of vasospasm and brain ischemia was obtained. The clinical outcomes of the treated patients were excellent. All patients presented with hemiplegia and stupor that resolved or markedly improved (within several days, two patients; within 12 hours, one patient). All three patients were discharged and were living at home at the time of manuscript submission.

CONCLUSION

These preliminary observations suggest that sodium nitroprusside delivered by an intrathecal route of administration may be a useful treatment for severe vasospasm complicating SAH in humans.

Effectiveness of intra-arterially infused papaverine solutions of various concentrations for the treatment of cerebral vasospasm

We evaluated the effect of intra-arterially infused papaverine solutions of various concentrations on cerebral vasospasm following subarachnoid haemorrhage. A total of 90 vascular territories in 46 patients with symptomatic cerebral vasospasm after subarachnoid haemorrhage were treated with intra-arterial infusions of papaverine. In all patients, papaverine was infused at the top of the internal carotid artery (ICA). Of the 90 vascular territories, 30 vascular territories in 14 patients were treated with an infusion of 0.1-0.2% (weight/volume) papaverine (Group 1), 30 vascular territories in 16 patients were treated with a 0.4% (w/v) papaverine infusion (Group 2), and 30 vascular territories in 16 patients were treated with an infusion of 0.8-2.0% (w/v) papaverine (Group 3). Among the three groups, we compared the vasodilatory effects of papaverine by assessing the angiographical and clinical improvements following the treatment. When 0.4% (w/v) papaverine was infused, 24 vascular territories (80%) were successfully dilated and 7 patients (44%) showed a marked reversal of neurological deficits due to vasospasm. Therefore, 80 mg/20 ml (0.4% (w/v)) papaverine infused over a 10-minute period proved to be a beneficial concentration. Transient focal neurological deficits due to the infusion of papaverine occurred in 1 Group 1 patient (7%), 1 Group 2 patient (6%), and 7 Group 3 patients (44%). Highly concentrated papaverine had a higher risk of temporary deterioration. In conclusion, the papaverine concentration of 0.4% (w/v) infused at the top of the ICA was a safe and adequate concentration for treating cerebral vasospasm.

Repeat intra-arterial papaverine for recurrent cerebral vasospasm after subarachnoid haemorrhage

We assessed the prevalence of recurrent vasospasm following failure of intra-arterial papaverine and the efficacy of repeat intra-arterial infusions of papaverine for control of recurrent vasospasm. Of 24 patients treated with intra-arterial papaverine for vasospasm following aneurysm surgery, 12 did not improve clinically after the initial treatment; 9 received second or third infusions on consecutive days; 6 received only a second infusion; and 3 received a third. Superselective infusion into the intracranial arteries was performed in all nine cases. Despite angiographic improvement after the initial or second infusions, all nine patients showed varying degrees of recurrent vasospasm at the time of the second or third treatment. Within 24 h of a second infusion, three of the six patients had significant clinical improvement, and one of these showed marked improvement soon after a third infusion. Our preliminary results suggest that repeat papaverine infusion may be a way of controlling recurrent or recalcitrant vasospasm.

Technical considerations on intra-arterial papaverine hydrochloride for cerebral vasospasm

Intra-arterial infusion of papaverine hydrochloride for subarachnoid hemorrhage-induced cerebral vasospasm has become an adjunctive endovascular therapy along with cerebral angioplasty. Our knowledge concerning the mechanism of action, method of administration and potential side effects of this therapeutic alternative are reviewed.

Endovascular treatment for acute thrombotic occlusion of the middle cerebral artery: local intra-arterial thrombolysis combined with percutaneous transluminal angioplasty

We report our experience in treating 15 patients with acute thrombotic occlusion of the M1 or M2 segment of the middle cerebral artery who underwent intra-arterial thrombolytic therapy alone or in combination with percutaneous transluminal angioplasty (PTA). The results were compared with those of 30 patients with acute embolic occlusion of the same artery. Intra-arterial thrombolysis was performed in 10 patients and thrombolysis combined with PTA in 5 in whom symptoms reappeared due to restenosis or reocclusion, or in whom recanalisation was not successfully accomplished by thrombolysis alone. In the patients with embolism recanalisation was observed in 28 (93 %) and there was no patient with reocclusion. In the patients with thrombosis recanalisation immediately after thrombolysis alone was observed in 9 of 15 (60%). Restenosis, with reappearance of symptoms, occurred in 2 of these (22 %). In the patients who also underwent PTA, angiography after 1 month did not demonstrate any restenosis or reocclusion. Thrombolysis combined with PTA for acute thrombotic stroke may provide an effective procedure for restoring patency and preventing reocclusion of the occluded artery.

Prevention of chronic cerebral vasospasm in dogs with milrinone

OBJECTIVE

Delayed cerebral ischemia resulting from vasospasm is a major cause of morbidity and death in patients with aneurysmal subarachnoid hemorrhage. Milrinone, because it inhibits Type IV cyclic adenosine monophosphate-specific phosphodiesterase enzyme in both cardiac and vascular smooth muscle, is a powerful inotrope and vasodilator, but it has little effect on heart rate or blood pressure. Because of these properties, milrinone is an attractive potential therapy after subarachnoid hemorrhage. The purpose of the present study was to investigate the effect of milrinone on chronic experimental cerebral vasospasm.

METHODS

A double-hemorrhage canine model of vasospasm was used to study the efficacy of milrinone. Angiographic vasospasm and systemic hemodynamics were compared in a treatment group of animals that received a loading dose of milrinone (0.05 mg/kg, intravenously) and then slow-release (0.05 microgram/kg/min) milrinone pellets (n = 10) and a control group that received placebo pellets (n = 9), over an 8-day period after the initial subarachnoid hemorrhage. The hemorrhage was created by injection of 4 ml of autologous, nonheparinized, arterial blood into the cisterna magna on Days 1 and 3. Hemodynamic measurements, including cardiac output determinations, were made on Days 0, 1, 3, 6, and 8 with a pulmonary artery catheter, and angiographic vasospasm was assessed on Day 8 by comparison with baseline angiograms.

RESULTS

Treatment with milrinone caused no significant changes in systemic hemodynamics. Angiographic vasospasm, however, was significantly reduced in the Day 8 angiograms for the treated group, compared with the control group (98.28 +/- 14.06 and 67.89 +/- 13.06% of original vessel cross-sectional area, respectively; P < 0.001).

CONCLUSION

Milrinone is effective in preventing chronic cerebral vasospasm in a canine model of experimental chronic cerebral vasospasm. This effect is independent of changes in systemic hemodynamics. Milrinone and related drugs warrant further investigation for the treatment of cerebral vasospasm.

Effect of intraarterial papaverine on cerebral circulation time

PURPOSE

To measure the mean cerebral circulation time (CCT) in patients with symptomatic vasospasm stemming from subarachnoid hemorrhage and to determine any change after papaverine treatment.

METHODS

We studied 27 patients who received intraarterial papaverine from November 1992 to August 1995 to determine the CCT in 59 carotid territories. CCT was measured from the first image in which contrast was seen above the supraclinoid internal carotid artery to the peak filling of parietal cortical veins. Angiograms at the time of presentation were examined in 19 of the 27 patients. A control population of 19 patients (30 carotid territories) was also studied.

RESULTS

The mean CCT on presentation was 6.8 seconds +/- 1.1. The prepapaverine mean CCT was 6.1 seconds +/- 1.2. The immediate postpapaverine mean CCT was 3.8 seconds +/- 0.8. CCT decreased in 58 of 59 territories treated with papaverine; the mean change was -35.7%. In eight of these patients, CCT rose on the following day to 6.1 seconds +/- 1.1. In the control group, mean CCT was 5.9 seconds +/- 0.8. The mean CCT in patients with subarachnoid hemorrhage was slightly prolonged on presentation relative to that in control subjects.

CONCLUSION

Intraarterial papaverine produces a consistent decrease in CCT in patients with vasospasm.

Development of calcitonin gene-related peptide slow-release tablet implanted in CSF space for prevention of cerebral vasospasm after experimental subarachnoid haemorrhage

The calcitonin gene-related peptide (CGRP), a known potent intrinsic cerebral vasodilator, is contained in the sensory nerves from trigeminal ganglia that inervate the cerebral arteries. We previously reported that human alpha CGRP (hCGRP) dilates spastic cerebral arteries after experimental subarachnoid haemorrhage (SAH) in rabbits. In the present study, we investigated the prophylactic potential of a sustained higher cerebrospinal fluid level of hCGRP against experimental cerebral vasospasm. An hCGRP slow-release tablet (hCGRP s-r tablet) was developed for cisternal implantation. Experimental SAH was induced by percutaneous cisternal injection of autologous arterial blood. Angiography was initiated on day 1 (before SAH) and performed everyday. The hCGRP s-r tablet was implanted into the cisterna magna on day 2 in the treated groups. The spastic response of the basilar artery was maximized on day 4 in the non-treated (80.7% of day 1) and the placebo-treated (79.3%) groups. In contrast, the arterial diameters on day 4 were 96.1% and 90.5% of day 1 in the groups implanted with hCGRP 24 micrograms and 153 micrograms s-r tablets, respectively. We also measured the concentration of hCGRP in the cerebrospinal fluid (CSF) following implantation of the hCGRP 24 micrograms s-r tablet in the cisterna magna. The hCGRP concentration before implantation was below the dectable level. Following implantation, the hCGRP level in the CSF was 23.12 nmol/L on the second day and remained at elevated levels until the fifth day. These experiments suggest that the intrathecal single implantation of the hCGRP s-r tablet could produce an elevated concentration of hCGRP in the CSF over five days and have prevented the cerebral vasospasm after SAH in the rabbit. The hCGRP s-r tablet may be clinically applicable in the treatment of patients with SAH against cerebral vasospasm.

[Cerebral infarct in chronic acetylsalicylic acid poisoning]

Salicylates increase the risk of hemorrhage. An ischemic brain infarct has not previously been described following intoxication with salicylates. Case report. A 58-year-old comatose patient was admitted with symptoms of a basilar artery thrombosis. A diagnostic angiography was impossible because laboratory results showed a prothrombin time (Quick) of 9% and a toxic salicylate level of 528 mg/l. During the next few days CCT and MRI scans revealed ischemic infarctions within the brain stem. Discussion. Salicylates can induce hemorrhage both by inhibiting platelet aggregation and - especially in higher doses - by vitamin K antagonism, leading to severe coagulopathy. The occurrence of an ischemic infarction, as presented in this case report, can be explained by a reduction of the vitamin K-dependent protein C level.

Prevention of cerebral vasospasm after experimental subarachnoid hemorrhage by RO 47-0203, a newly developed orally active endothelin receptor antagonist

Since their discovery in 1988, endothelins have attracted scientific interest because of their extremely potent and long-lasting vasoconstrictive effects, similar to cerebral vasospasm in humans. In this study, the efficacy of the orally active endothelin receptor antagonist RO 47-0203 for prevention of cerebral vasospasm after experimental subarachnoid hemorrhage, using the two-hemorrhage dog model, was investigated. Twenty-eight beagle dogs were used in this laboratory experiment. Fourteen animals each were assigned to the treatment and control groups. In the treatment group, each dog received two single doses of 30 mg/kg RO 47-0203 orally per day. The diameter of the basilar artery decreased from 1.36 +/- 0.17 mm on Day 1 to 1.19 +/- 0.23 mm on Day 8 in the treatment group, whereas in the control group, the vessel diameter decreased from 1.48 +/- 0.19 mm on Day 1 to 1.02 +/- 0.22 mm on Day 8. These results corresponded to a decrease of vessel diameter of 13.1% +/- 11.2% in the treatment group and a decrease of vessel diameter of 30.7% +/- 12.4% in the control group (P < 0.001). Concentrations of endothelin-1 in cerebrospinal fluid significantly increased with time after subarachnoid hemorrhage. These results emphasize the important role of endothelin in the development of cerebral vasospasm and present first-time evidence that prevention of cerebral vasospasm can be achieved by the endothelin receptor antagonist RO 47-0203.

Acute embolic carotid occlusion after cardiac catheterization: effect of local intra-arterial urokinase thrombolysis

A 64-year-old woman developed a severe embolic cerebral attack with total left hemiplegia approximately 30 hours after cardiac catheterization for mitral stenosis. She underwent intra-arterial thrombolysis of the right internal carotid artery four and one-half hours after the onset of neurologic deficit with subsequent recanalization of the occluded vessel and near complete neurologic recovery.

Papaverine-sensitive vasospasm and arterial contractility and compliance after subarachnoid hemorrhage in dogs

This study examined the relationship between papaverine-sensitive and -insensitive components of vasospasm, arterial contractility and compliance, and time after subarachnoid hemorrhage (SAH) in dogs. Eighteen dogs underwent angiography and then two intracisternal injections of blood. Angiography was repeated 4 (n = 5), 7 (n = 4), 10 (n = 4), or 14 (n = 5) days later. Papaverine, 100 to 200 mg, was infused into the basilar artery, and angiography was repeated. Four additional dogs had cerebral angiography only and served as controls. The basilar arteries were removed and studied pharmacologically. Significant vasospasm of the basilar artery was observed each time after SAH. Papaverine significantly reversed vasospasm at 4 and 7 days (88 +/- 6% and 63 +/- 11% of vasospasm reversed; analysis of variance, P < 0.05). The papaverine-insensitive component of vasospasm increased significantly with increasing time after SAH and with increasing severity of vasospasm. Arterial contractility and compliance decreased significantly with increasing time after SAH and were significantly related to the degree of papaverine-insensitive vasospasm but not to the severity of vasospasm. In conclusion, the majority of vasospasm early after SAH in dogs was caused by reversible vasoconstriction. The ability of papaverine to reverse vasospasm depended on the time after SAH and on the severity of vasospasm, a finding that may be important to the use of papaverine in humans. The pathological and biochemical basis for the association between papaverine-insensitive vasospasm and reduced arterial wall contractility and compliance remains to be determined.

Recovery from primary deep cerebral venous sinus thrombosis with recanalisation

A 50-year-old woman with idiopathic deep cerebral sinus and vein thrombosis (DCVT) had cerebellar disturbance prior to impaired consciousness. CT and MRI revealed haemorrhagic infarction in the cerebellum and signal changes suggesting infarction in the thalamus and basal ganglia bilaterally. The straight sinus and internal cerebral vein (ICV) were dense on CT. On angiography, the vein of Galen (VG) and straight sinus were not seen. Following clinical recovery, CT and MRI became normal, and angiography showed recanalization of the VG and ICV. The relationship between cerebellar infarction and DCVT, and signal changes on CT and MRI are discussed.

Intra-arterial infusion of papaverine combined with intravenous administration of high-dose nicardipine for cerebral vasospasm

The clinical effect of combination therapy with high doses of intravenous nicardipine and intra-arterial infusion of papaverine on symptomatic vasospasm after subarachnoid haemorrhage (SAH) was analysed retrospectively. In 66 of 122 patients who underwent early aneurysm surgery between 1990 and 1993, the intracranial haemodynamics were documented by transcranial Doppler (TCD) ultrasonography. 33 of these 66 patients received high dose nicardipine intravenously (Group I); the other 33 patients were not treated with calcium antagonists (Group II). Symptomatic vasospasm occurred in 6 Group I patients (18%) and in 13 (39%) in Group II patients. All 19 symptomatic patients received an intra-arterial infusion of papaverine; 15 patients (79%) responded well to this therapy and the symptoms were reversed quickly. Although the mean flow velocity (MFV) was not different between the two groups, it was reduced significantly after papverine infusion. Our retrospective analysis suggests that symptomatic vasospasm can be treated effectively with the combination of intravenous high dose nicardipine and intra-arterial infusion of papaverine, and that the correct timing of the infusions is crucial.

Effect of GSH on cerebral vasospasm in dogs

Reduced glutathinone (tau-glutamylcysteinglycine, GSH) is a scavenger for oxygen radicals and plays in important role in protection of cells from ischemia and from the harmful effects of free oxygen radicals. Free oxygen radicals due to cerebral vasospasm increase in both vasospasm and proliferative vasculopathy. This experiment was performed to determine whether GSH plays a role in cerebral vasospasm after subarachnoid hemorrhage by preventing the harmful effects of free oxygen radicals. In this study, GSH was administered intraarterially and intracisternally following vasospasm of the canine basilar artery. Less vasospasm was observed in the group treated with GSH intraarterially following subarachnoid hemorrhage than in the one treated with GSH intracisternally and in the control group. The arterial wall was investigated ultrastructurally. We evaluated the effect of the anti-oxidating substance through the activity of superoxide dismutase in the arterial wall. We compared the effect of glutathione reductase in the two groups treated with GSH intraarterially and intracisternally. Arterial degeneration was more prominent in the group in which GSH was used intracisternally, while the superoxide dismutase levels were low. In contrast, arterial degeneration was less in the other group in which GSH was used intraarterially, while the superoxide dismutase levels were high.

Successful treatment of an acute thrombosis of an intracranial vertebral artery endarterectomy with urokinase

This is a case report of a 47-year-old man admitted with a 7-month history of disequilibrium, multiple reversible vertebrobasilar ischemic attacks, and one submaximal completed stroke in the left posterior inferior cerebellar artery distribution. Vertebrobasilar ischemic attacks continued despite anti-coagulation, and orthostatic symptomatology suggested a significant hemodynamic component contributing to the posterior circulation ischemia. Angiography confirmed bilateral high-grade stenoses of the intracranial vertebral arteries. A right intracranial vertebral artery endarterectomy was performed with electroencephalographic and somatosensory evoked potential monitoring and protection with barbiturate infusion. The arteriotomy was closed with a vein patch. Postoperatively, the endarterectomy site thrombosed. This thrombosis was completely reversed with 220,000 U of urokinase selectively infused intra-arterially at the site of thrombosis. This procedure was not complicated by hemorrhage or distal embolization. The vertebral artery was confirmed to be patent 24 hours and 7 days after the urokinase injection. The patient sustained a borderzone infarction in the right cerebellar hemisphere without neurological deficits and was discharged home well.

Transient neurologic events associated with intraarterial papaverine infusion for subarachnoid hemorrhage-induced vasospasm

This report describes three patients who experienced transient neurologic events associated with intraarterial papaverine infusion in the vertebrobasilar system. Two of these involved respiratory depression and underscore the need for careful monitoring and, when required, cardiopulmonary support.

Use of a calcium channel blocker (nicardipine HCl) in the treatment of childhood moyamoya disease

Moyamoya disease is a cerebrovascular disease characterized radiologically by progressive narrowing and occlusion of the arteries contributing to the circle of Willis and its branches. There is formation of an exuberant collateral network of blood vessels at the base of the brain, which is thought to arise in response to chronic ischemia. Clinically, the course is variable, with patients having repeated transient ischemic attacks, strokes, migraine, and seizures. Effective treatment is not available. The etiology and pathophysiology of moyamoya disease are largely unknown. Two patients with arteriographically proven moyamoya disease were identified. Both patients were symptomatic before age 5 years. Despite successful encephaloduroarteriosynangiosis revascularization procedures, they continued to experience an inexorable downhill course. A calcium channel blocker (nicardipine HCl) was introduced in order to prevent further symptoms. After the introduction of nicardipine, no further strokes occurred in either patient. There were no further episodes of transient ischemic attacks, seizures, or headache in one patient and decreased frequency in the other. In patients with moyamoya disease, nicardipine may have a beneficial effect on cerebral hemodynamics and may prevent ischemic sequelae by optimizing existing collateral circulation.

Effects of new 21-aminosteroid tirilazad mesylate (U74006F) on chronic cerebral vasospasm in a "two-hemorrhage" model of beagle dogs

The present work aimed at examining the effect of tirilazad mesylate (U74006F), a newly developed lipid peroxidation inhibitor, on the intraluminal narrowing of basilar artery subjected to subarachnoid hemorrhage (SAH) in beagle dogs. In Experiment 1, an intravenous bolus injection of either vehicle or U74006F (0.5, 1.5 and 3.0 mg/kg) was repeated every 8 hours after an induction of the first SAH until the animals were killed. A dose of 0.5 mg/kg of U74006F provided the greatest beneficial effect. In Experiment 2, an intravenous infusion of 100 ml of saline containing either vehicle or U74006F (0.3 and 1.0 mg/kg) was given in the same time schedule as in Experiment 1. Post-SAH treatment of U74006F, at a dosage of approximately 0.5 mg/kg, showed a beneficial effect by infusion as well as by bolus administration. The present study demonstrates that U74006F has an ability to prevent chronic vasospasm in the canine SAH model.

Effects of prophylactic intrathecal administrations of nicardipine on vasospasm in patients with severe aneurysmal subarachnoid haemorrhage

Calcium antagonists are currently most widely used for chronic cerebral vasospasm after aneurysmal subarachnoid haemorrhage (SAH). However, the vasodilatory effects of systemically administered calcium antagonists can be limited secondary to hypotension. We previously compared intrathecal and intravenous routes of administration of nicardipine. Intrathecal administration of nicardipine significantly dilated spastic basilar arteries on day 7 in a two-haemorrhage canine model of vasospasm. In the present communication, the effects of prophylactic, serial administration of intrathecal nicardipine on vasospasm was examined in 50 patients. Patients were classified as Fisher SAH group 3 and all had their aneurysms clipped within 3 days of SAH. Following placement of a cisternal drain, 2 mg of nicardipine was injected, three times each day for an average of 10 days. The control group consisted of 91 similar patients with cisternal drainage not treated with nicardipine. Intrathecal administration of nicardipine decreased the incidence of symptomatic vasospasm by 26%, angiographic vasospasm by 20% and increased good clinical outcome at one month after the haemorrhage by 15%. Postoperative angiograms revealed that patients in the nicardipine group showed less vasospasm of major cerebral arteries, near the tip of a drain in the basal cistern, but vasospasm in the A2 and M2 segments was not decreased. Radio-isotope cisternography suggested that nicardipine might not reach the subarachnoid space around A2 and M2 segments. Nine patients complained of headache probably secondary to nicardipine induced vasodilation. Two patients suffered from meningitis, both were successfully treated. Intrathecal administration nicardipine appears to be effective in the treatment of vasospasm, but side effects were significant.

[Evaluation of 2 modalities of use of propofol in cerebral angiography]

Fifty eight adult patients suffering from different intracranial lesions and scheduled for cerebral angiography were given propofol. In the first group (38 patients) brief periods of anaesthesia were induced and reinduced by means of 1.5 mg/kg of propofol iv and sometimes extended with boluses of 25-50 mg of this anesthetic. The patients were premedicated with 0.5 mg atropine im 30-40 min before the induction. Fentanyl, droperidol and diazepam in various combinations and doses were injected, im together with the atropine and iv 1-2 min before the induction, to obtain long-lasting sedations. In the second group (20 patients) the induction of the anaesthesia started 20-35 min after 0.5 mg of atropine im and 1 min after 0.1 mg of fentanyl iv. The induction was based on a bolus of 2.5 mg/kg of propofol and it was followed by suxamethonium, tracheal intubation and mechanical ventilation with N2O 70% in O2. An adequate depth of anaesthesia was maintained with supplemental doses of 50 mg of propofol, frequently associated with 25 mg of suxamethonium. Both methods proved to be reliable and safe. Nevertheless, the second method provided a better stability as far as a number of physiologic variables is concerned.