Effectiveness of sildenafil and U-74389G in a rat model of colitis.

BACKGROUND: Crohn disease is still incurable. Compounds with anti-inflammatory and/or antioxidative effects are tested in various preclinical models of the disease. Our aim was to investigate the effects of sildenafil and lazaroid U-74389G in an experimental rat model of trinitrobenzenesulfonic acid-induced colitis. MATERIALS AND METHODS: Trinitrobenzenesulfonic acid was instilled into the colon of all male Wistar rats except for the rats belonging to the first group. For 6 days, the animals in group 3 were administered daily sildenafil orally, the rats in group 4 were administered daily U-74389G intravenously, and the rats in group 5 were coadministered daily sildenafil orally and intravenous U-74389G. The rats in groups 1 and 2 were not administered any treatment. During the study, the weights were recorded as a marker of clinical condition. The colon damage was evaluated using macroscopic colon mucosal damage index (CMDI), microscopic (Geboes score), and biochemical methods (tissue tumor necrosis factor [TNF]-α and malondialdehyde [MDA]). RESULTS: Sildenafil reduced TNF-α tissue levels and increased body weight. U-74389G reduced TNF-α, the macroscopic index of mucosal damage score (CMDI) and increased body weight. The combined treatment with sildenafil and U-74389G reduced tissue levels of both TNF-α and MDA, lowered CMDI and microscopic Geboes score, and increased body weight. CONCLUSIONS: U-74389G demonstrated a significant anti-inflammatory activity related to its ability to reduce colonic TNF-α, CMDI score, and improve weight change. We confirmed that sildenafil has anti-inflammatory capacity by reducing colonic TNF-α and by improving body weight. Finally, the combined treatment showed superior effects by reducing colonic TNF-α, colonic MDA, CMDI score, Geboes score, and by improving weight.

Neuroprotection for ischaemic stroke: translation from the bench to the bedside.

Neuroprotection seeks to restrict injury to the brain parenchyma following an ischaemic insult by preventing salvageable neurons from dying. The concept of neuroprotection has shown promise in experimental studies, but has failed to translate into clinical success. Many reasons exist for this including the heterogeneity of human stroke and the lack of methodological agreement between preclinical and clinical studies. Even with the proposed Stroke Therapy Academic Industry Roundtable criteria for preclinical development of neuroprotective agents for stroke, we have still seen limited success in the clinic, an example being NXY-059, which fulfilled nearly all the Stroke Therapy Academic Industry Roundtable criteria. There are currently a number of ongoing trials for neuroprotective strategies including hypothermia and albumin, but the outcome of these approaches remains to be seen. Combination therapies with thrombolysis also need to be fully investigated, as restoration of oxygen and glucose will always be the best therapy to protect against cell death from stroke. There are also a number of promising neuroprotectants in preclinical development including haematopoietic growth factors, and inhibitors of the nicotinamide adenine dinucleotide phosphate oxidases, a source of free radical production which is a key step in the pathophysiology of acute ischaemic stroke. For these neuroprotectants to succeed, essential quality standards need to be adhered to; however, these must remain realistic as the evidence that standardization of procedures improves translational success remains absent for stroke.

Tirilazad for aneurysmal subarachnoid haemorrhage.

BACKGROUND: Delayed cerebral ischaemia is a significant contributor to poor outcome (death or disability) in patients with aneurysmal subarachnoid haemorrhage (SAH). Tirilazad is considered to have neuroprotective properties in animal models of acute cerebral ischaemia. OBJECTIVES: To assess the efficacy and safety of tirilazad in patients with aneurysmal SAH. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched October 2009); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2009); MEDLINE (1966 to October 2009); EMBASE (1980 to October 2009); and the Stroke Trials Directory, the National Center for Complementary and Alternative Medicine, and the National Institute of Health Clinical Trials Database (searched October 2009). We handsearched 10 Chinese journals, searched the reference lists of relevant publications, and contacted the manufacturers of tirilazad. SELECTION CRITERIA: Randomised trials of tirilazad started within four days of SAH onset, compared with placebo or open control in patients with aneurysmal SAH documented by angiography and computerised tomography (CT) scan or cerebrospinal fluid examination, or both. DATA COLLECTION AND ANALYSIS: We extracted data relating to case fatality, poor outcome (death, vegetative state, or severe disability), delayed cerebral ischaemia (or symptomatic vasospasm), cerebral infarction and adverse events of treatments. We pooled the data using the Peto fixed-effect method for dichotomous data. MAIN RESULTS: We included five double-blind, placebo-controlled trials involving 3821 patients; there was no significant heterogeneity. Oral or intravenous nimodipine was used routinely as a background treatment in both groups in all trials. There was no significant difference between the two groups at the end of follow up for the primary outcome, death (odds ratio (OR) 0.89, 95% confidence interval (CI) 0.74 to 1.06), or in poor outcome (death, vegetative state or severe disability) (OR 1.04, 95% CI 0.90 to 1.21). During the treatment period, fewer patients developed delayed cerebral ischaemia in the tirilazad group than in the control group (OR 0.80, 95% CI 0.69 to 0.93). Subgroup analyses did not demonstrate any significant difference in effects of tirilazad on clinical outcomes. Leukocytosis and prolongation of Q-T interval occurred significantly more frequently in the treatment group in only one trial evaluating tirilazad at high dose. There was no significant difference in infusion site disorders or other laboratory parameters between the two groups. AUTHORS' CONCLUSIONS: There is no evidence that tirilazad, in addition to nimodipine, reduces mortality or improves poor outcome in patients with aneurysmal SAH.

Clinical review: Prevention and therapy of vasospasm in subarachnoid hemorrhage.

Vasospasm is one of the leading causes of morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). Radiographic vasospasm usually develops between 5 and 15 days after the initial hemorrhage, and is associated with clinically apparent delayed ischemic neurological deficits (DID) in one-third of patients. The pathophysiology of this reversible vasculopathy is not fully understood but appears to involve structural changes and biochemical alterations at the levels of the vascular endothelium and smooth muscle cells. Blood in the subarachnoid space is believed to trigger these changes. In addition, cerebral perfusion may be concurrently impaired by hypovolemia and impaired cerebral autoregulatory function. The combined effects of these processes can lead to reduction in cerebral blood flow so severe as to cause ischemia leading to infarction. Diagnosis is made by some combination of clinical, cerebral angiographic, and transcranial doppler ultrasonographic factors. Nimodipine, a calcium channel antagonist, is so far the only available therapy with proven benefit for reducing the impact of DID. Aggressive therapy combining hemodynamic augmentation, transluminal balloon angioplasty, and intra-arterial infusion of vasodilator drugs is, to varying degrees, usually implemented. A panoply of drugs, with different mechanisms of action, has been studied in SAH related vasospasm. Currently, the most promising are magnesium sulfate, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, nitric oxide donors and endothelin-1 antagonists. This paper reviews established and emerging therapies for vasospasm.

Effect of combined therapy with hyperbaric oxygen and antioxidant on infarct volume after permanent focal cerebral ischemia.

The aim of the present study was to evaluate the efficiency of combination of hyperbaric oxygen (HBO) and an antioxidant on permanent focal cerebral ischemia. Male Wistar rats underwent permanent middle cerebral artery occlusion (MCAO). Then, animals were randomly assigned to one of four groups: the control group (n=9) received no treatment, HBO group (n=9) was treated for 90 min at 2.5 absolute atmosphere for 3 days, the U-74389G group (n=8) received single U-74389G injection (3 mg/kg), the HBO + U-74389G group (n=8) received both HBO and U-74389G treatments. Treatments were initiated within the first 10 min after MCAO. After 3 days, the infarct volumes in rat brains were measured. The infarct ratios were 25.6+/-6.5 % for the control group, 21.9+/-6.4 % for the HBO group, 15.7+/-5.7 % for U-74389G group and 12.5+/-3.8 % for HBO + U74389G group. The infarct volumes were significantly reduced in rats treated with U-74389G (p<0.05) and combination therapy (p<0.05). HBO failed to reduce infarct volume significantly. We concluded that 1) U-74389G is more beneficial than HBO on permanent MCAO in rats, and 2) a combined therapy failed to significantly improve infarct volume more than either single treatment.

Neuronal degeneration and iNOS expression in experimental brain contusion following treatment with colchicine, dexamethasone, tirilazad mesylate and nimodipine.

BACKGROUND: The pathophysiological mechanisms of secondary neurological injury after traumatic brain injury are complex. Post-traumatic biochemical reactions include parenchymal inflammation, free radical production, increased intracellular calcium and lipid peroxidation and nitric oxide production. The relative importance of each mechanism is unknown in brain contusions. This study was undertaken to investigate protection by the neuroprotective and/or anti-inflammatory drugs that have different putative mechanisms of action: colchicine, dexamethasone, tirilazad mesylate and nimodipine. METHOD: A brain contusion was produced using a weight-drop model in rats. The animals were treated with either one of the drugs at previously defined relevant dosage or control. Fluoro-Jade labelling, TUNEL-staining and immunohisto-chemistry were used to study neuronal degeneration, cellular apoptosis and iNOS expression. In addition, the number of surviving neurons after 14 days was determined. FINDINGS: The number of degenerating neurons was significantly reduced in all treatment groups at 24 hours while the total number of apoptotic cells including inflammatory cells and glia was unchanged. iNOS-expression was reduced in all treatment groups at 24 hours but not later. Only colchicine and tirilazad mesylate significantly enhanced neuronal survival at 14 days after injury. CONCLUSIONS: The findings underscored that an early neuroprotective effect does not necessarily lead to increased long-term neuronal survival. The absence of a significant long-term effect with nimodipine and dexamethasone agrees with clinical studies. Colchicine with an anti-macrophage/anti-inflammatory activity and the free radical scavenger tirilazad mesylate were effective for amelioration of experimental contusion with moderate energy transfer. Early neuroprotection may to some extent target iNOS via different pathways since all tested drugs affected both iNOS expression and neuronal degeneration.

Factors associated with the development of vasospasm after planned surgical treatment of aneurysmal subarachnoid hemorrhage.

OBJECT: The goal of this study was to determine factors associated with the development of symptomatic vasospasm among patients with aneurysmal subarachnoid hemorrhage (SAH) who participated in the randomized, double-blind, placebo-controlled trials of tirilazad between 1991 and 1997. METHODS: Data obtained from 3567 patients entered into trials of tirilazad were analyzed using uni- and multivariate logistic regression to determine factors that predict the development of symptomatic vasospasm. Symptomatic vasospasm was defined by clinical criteria accompanied by laboratory- and radiologically determined exclusion of other causes of neurological deterioration. Transcranial Doppler ultrasonographic and/or angiographic confirmation was not required. In these patients, the aneurysms were scheduled to be treated surgically, and no patient undergoing endovascular treatment was included. A multivariate analysis showed that factors significantly associated with vasospasm were age 40 to 59 years, history of hypertension, worse neurological grade, thicker blood clot on the cranial computerized tomography (CT) scan obtained on hospital admission, larger aneurysm size, presence of intraventricular hemorrhage (IVH), prophylactic use of induced hypertension, and not participating in the first European tirilazad study. CONCLUSIONS: Symptomatic vasospasm was associated with the amount of SAH on the CT scan, the presence of IVH, and the patient's neurological grade. The association with patient age may reflect alterations in vessel reactivity associated with age. A history of hypertension may render the brain more susceptible to symptoms from vasospasm. The explanation for the relationships with aneurysm size, use of prophylactic induced hypertension, and the particular study is unclear.

Drug development in spinal cord injury: what is the FDA looking for?

It has long been recognized that much of the post-traumatic degeneration of the spinal cord following injury is caused by a secondary injury process that occurs during the first minutes, hours, and days after spinal cord injury (SCI). A key biochemical event in that process is reactive oxygen-induced lipid peroxidation (LP). Indeed, the administration of a high-dose regimen of the glucocorticoid steroid methylprednisolone (MP) has been shown to inhibit post-traumatic LP in animal models of SCI, and to improve neurological recovery in spinal cord-injured humans. This resulted in the registration of high-dose MP for acute SCI in several countries, although not in the U.S. Nevertheless, this treatment quickly became the standard of care for acute SCI, since it was already on the U.S. market for many other indications. Subsequently, it was demonstrated that the nonglucocorticoid 21-aminosteroid tirilazad could duplicate the antioxidant neuroprotective efficacy of MP in SCI models, and evidence of human efficacy has been obtained. This article explains the process of the discovery, development, and Food and Drug Administration regulation of new drugs for SCI; reviews the past development of MP and tirilazad for acute SCI; identifies the regulatory complications involved in future SCI drug development; and suggests some promising therapeutic approaches that could either replace or be added to high-dose MP.

[Cerebral vasospasm after subarachnoid hemorrhage. Current possibilities of prevention and treatment]. / Skurcz naczyn mózgowych po krwotoku podpajeczynówkowym. Obecne mozliwosci zapobiegania i leczenia.

Cerebral vasospasm is a complication diagnosed in angiography among about 2/3 of patients after subarachnoid haemorrhage with ruptured cerebral aneurysm. In half of the cases it appears in disturbances of consciousness, neurological deficits and vegetative disturbances. It's final result can be ischemic stroke. Among patients with symptomatic cerebral vasospasm around 1/3 fully recover in 1/3 of cases persistent neurological deficit remains and 1/3 of the patients die. Authors basing on literature and taking into consideration their own experience, reviewed and estimated current methods of prevention and treatment of cerebral vasospasm. Discussed mainly were methods which had been used in every day clinical practice, however some of them still remain controversial. The accepted model of treatment suggests as follows: 1. The exclusion of the aneurysm which was the cause of haemorrhage from the circulation and clot removal from the subarachnoid space; 2. Nimodipine administration; 3. Undertaking hemodynamic treatment; 4. Aminosteroid administration; 5. Performance of angioplasty in the case of lack of reaction to previous types of treatment of cerebral vasospasm.

Chronic effects of an aminosteroid on microdialytically measured parameters after experimental middle cerebral artery occlusion in the rat.

The effects of the neuroprotective aminosteroid U74006F (tirilazad mesylate, Freedox) were monitored microdialytically in rat cortex during three 4h periods beginning immediately, 25h and 49h after permanent middle cerebral artery occlusion. Either U74006F or vehicle only was administered 15 min, 2h, 6h, 12h and 24h after operation. The dialysate was analysed for on-line pH, ascorbic acid, uric acid, glucose and lactate. The efficacy of post-ischaemic treatment was shown by: a) lesion volume 53h after operation was significantly smaller in U74006F-treated animals; b) microdialytic findings were very similar to those found previously with pre-ischaemic drug application (reduction in release of ascorbic acid, uric acid and lactate, increased pH); c) an effect of U74006F on lactate release could still be seen on days 2 and 3; and d) increases in uric acid on days 2 and 3, possibly reflecting delayed cell death, were smaller in aminosteroid treated animals.

Emerging potentials for an antioxidant therapy as a new approach to the treatment of systemic sclerosis.

Oxidative stress, favoring disease progression by a rapid degeneration of endothelial cell function is deeply involved in Systemic Sclerosis (SSc) pathogenesis. Raynaud's phenomenon (RP), present in 90% of patients with SSc, provoking frequent daily episodes of hypoxia-reperfusion injury, produces several episodes of free radicals-mediated endothelial derangement. These events results in a positive feedback effect of luminal narrowing and ischemia and therefore to the birth of a vicious cycle of oxygen free radicals (OFR) generation, leading to endothelial damage, intimal thickening and fibrosis. Thus ischemia and reperfusion are two criticals events that may induce oxidative stress and inactivation of antioxidant enzymes. In RP and SSc, a reduced concentration of ascorbic acid, alpha-tocopherol and beta-carotene as well as low values of Selenium have been reported. This antioxidative potential deficiency increases the propensity to oxidative stress. favoring the development of injury mediated by OFR. We reviewed several antioxidant compounds, aiming at their capacity of reverting endothelial dysfunction and damage, scavenging lipid peroxidation and reducing multiple episodes of hypoxia-reperfusion injury. In order to interrupt SSc vicious cycle, we propose a main strategy for SSc treatment by a supplementation of antioxidants and different kind of drugs with antioxidant property, such as Lazaroids, Resveratrol, Melatonin and Probucol.

A 21-aminosteroid, U-74006F, attenuates endotoxin-induced lung injury in awake sheep.

The purpose of the present study was to examine the efficacy of U-74006F, a 21-aminosteroid, on lung dysfunction induced by endotoxaemia in awake sheep with lung lymph fistula and haemodynamic monitoring. We measured pulmonary haemodynamics, lung lymph balance, circulating leucocyte count, arterial blood gas tensions, and levels of thromboxane (Tx) B2 and 6-keto-prostaglandin (PG) F1 alpha in plasma and lung lymph. We performed two experiments. In experiment 1 (n = 6), we intravenously infused Escherichia coli lipopolysaccharide endotoxin (1 microgram/kg) over 30 min and observed the parameters over 5 h. In experiment 2 (n = 6), we pretreated sheep with an intravenous bolus of U-74006F (2 mg/kg) 30 min before the infusion of endotoxin in the same manner of experiment 1, and continuously infused U-74006F (0.5 mg/kg per h) over 5 h after the bolus during the experiment. The U-74006F significantly suppressed the early pulmonary hypertension, the late increase in pulmonary permeability and the elevations of TxB2 and 6-keto-PGF1 alpha levels in plasma and lung lymph during the early period following endotoxaemia, although the compound did not change the time course of leucocytopenia and hypoxaemia. These findings suggest that the administration of U-74006F attenuates the lung dysfunction induced by endotoxaemia in awake sheep.

Anti-inflammatory effects of U74389F in a rat model of intestinal ischemia/reperfusion injury.

OBJECTIVE: To investigate the role of eicosanoid generation and neutrophilic infiltration in the protective effects of U74389F against ischemia/reperfusion injury in the small intestines of rats. DESIGN: Prospective, randomized, controlled study. SETTING: University research laboratory. SUBJECTS: Adult, male Sprague-Dawley rats weighing between 200 and 300 g. INTERVENTIONS: Groups (5-8) of rats treated with U74389F or vehicle were subjected to a sham operation and 30 mins of ischemia by occlusion of the superior mesenteric artery or 30 mins of ischemia followed by 60 or 120 mins of reperfusion. U74389F (2.5 mg/kg i.v.) or vehicle (citrate buffer) were slowly injected 2 mins before ischemia. MEASUREMENTS AND MAIN RESULTS: Ischemia significantly (p < .05) increased mucosal injury (0 [normal] to 5) in both U74389F and untreated rats. In contrast, U74389F significantly (p < .05) attenuated the severity of injury after reperfusion. In vehicle-treated rats, ischemia/reperfusion significantly reduced villus height in both U74389F and untreated groups. However, the surface epithelial layer was intact in the U74389F but not in the vehicle-treated group. In addition, compared with the vehicle-treated group, U74389F significantly reduced neutrophil infiltration and prevented the increase in leukotriene B4 and prostaglandin E2 in response to ischemia and reperfusion. CONCLUSIONS: This study demonstrates that the mechanism of U74389F against mesenteric ischemia/reperfusion includes a delay and reduction of neutrophilic infiltrate, an inhibition of leukotriene B4 production, and a facilitation of mucosal restitution.

Beneficial effects of the radioprotectant 21-aminosteroid U-74389G in a radiosurgery rat malignant glioma model.

PURPOSE: To evaluate the radioprotectant effects of the 21-aminosteroid U-74389G on the rat C6 glioma model after stereotactic radiosurgery. Because radiosurgery causes both tumor cytotoxicity, as well as regional brain edema, we hypothesized that this drug might exhibit advantageous or deleterious effects on healthy and neoplastic tissue. METHODS: Rats were implanted with 10(6) C6 glioma cells into the right frontal brain and randomized to a Control Group (n = 18), radiosurgery on Day 14 (50% isodose = 35 Gy) (n = 15), or radiosurgery preceded by a single 15 mg/kg intravenous dose of 21-aminosteroid (n = 27). All animals were killed by 90 days and evaluated for survival, tumor size, the presence or absence of regional parenchymal edema, or radiation-induced vasculopathy. RESULTS: After tumor implantation, median survival in the Control Group was 23 days. Significant improvements in median survival were noted after RS alone (median, 31 days; p = 0.02), and RS plus 21-aminosteroid (median, 59 days; p < 0.0001). In the Control Group, mean tumor diameter was 5.4 mm. After RS alone, the mean diameter was 3.2 mm (p = 0.002), and after RS plus 21-aminosteroid, 2.9 mm (p = 0.0002). In the Control Group, the tumor grew as a hypercellular, compact mass. Only 3 of 18 animals had peritumoral edema. In contrast, 7 of 15 animals in the RS group had evidence of edema (p = 0.006), but rats that received 21-aminosteroid showed no increase compared to controls (p = 0.38). Similarly, 6 of 15 animals that had radiosurgery alone showed evidence of vasculopathy (p = 0.005) compared to no animals in the control group and only 2 of 27 aminosteroid-treated animals. CONCLUSIONS: The 21-aminosteroid U-74389G exhibits a radioprotectant effect on normal brain tissue, but does not appear to protect the tumor in an in vivo rat radiosurgery model. We believe that the observed beneficial effects on healthy brain led to significant prolongation of animal survival; perhaps, by limiting the adverse effects of high-dose radiosurgery. This radioprotectant should now be evaluated in randomized clinical trials in patients with malignant brain tumors.

Monotherapy with dextromethorphan or tirilazad--but not a combination of both--improves outcome after transient focal cerebral ischemia in rats.

Cell death after cerebral ischemia is mediated by a massive release of excitatory amino acids, generation of free radicals, and - a crucial step - calcium influx into cells. We examined the hypothesis that concurrent administration of drugs ameliorating brain damage via different mechanisms would result in a synergistic neuroprotective effect. The neuroprotective efficacy of two clinically available drugs - the N-methyl-D-aspartate and calcium-channel antagonist dextromethorphan (DM) and the antioxidant tirilazad - were studied in monotherapy and in combination in a rat model of transient focal ischemia. Male Sprague-Dawley rats were subjected to 90 min of middle-cerebral-artery occlusion by an intraluminal filament technique. The animals were randomly assigned to one of four treatments (n=10 each): (1) vehicle-treated controls, (2) DM, (3) tirilazad, (4) DM+tirilazad. Drugs or vehicles were administered 15 min before ischemia and at reperfusion. Local cerebral blood flow (LCBF) was bilaterally recorded by continuous laser Doppler flowmetry. Functional deficits were quantified by daily neurological examinations. Infarct volume was assessed planimetrically after 7 days. DM prevented post-ischemic hypoperfusion. Tirilazad did not influence LCBF. Monotherapy with DM or tirilazad improved neurological function and reduced infarct volume by 45% and 48%, respectively. Combination therapy failed to influence neurological recovery and infarct volume. Although, from pharmacological point of view, a synergistic neuroprotective effect is expected, combination of dextromethorphan and tirilazad may lead to mutual inhibition or potentiate adverse effects.

The 21-aminosteroid 16-desmethyl tirilazad mesylate prevents necroinflammatory changes in experimental alcoholic liver disease.

We investigated the potential of 16-desmethyl tirilazad mesylate, a member of 21-aminosteroids, to ameliorate alcohol-induced liver injury. Four groups (five rats/group) of male Wistar rats were studied. One group of rats was fed fish oil and ethanol (FE) for 4 weeks, and a second group received isocaloric amounts of dextrose instead of ethanol (FD). The third (FE-LAZ) and fourth (FD-LAZ) groups received the addition of 10 mg/kg/day of 16-desmethyl tirilazad mesylate (U74389) daily via intragastric tube. Liver samples were analyzed for histopathology, nonheme iron, lipid peroxidation and levels of mRNA for tumor necrosis factor-alpha (TNF-alpha) and cyclooxygenase-2 (COX-2). Concentrations of endotoxin and 8-isoprostane were measured in plasma. Membrane ATPases were measured in isolated membrane red cells. FE rats developed fatty liver, necrosis and inflammation. Treatment with the 21-aminosteroid resulted in prevention of necroinflammatory changes, but the degree of fatty liver was unchanged. The absence of necroinflammatory changes in the FE-LAZ group was accompanied by a decrease in levels of nonheme iron, lipid peroxidation, TNF-alpha mRNA and COX-2 mRNA. Ethanol administration decreased membrane Ca(++)-ATPase and calmodulin-stimulated Ca(++)-ATPase, and the decrease was reversed by 21-aminosteroid treatment. The data indicate that the improvement in the degree of necrosis and inflammation in the rats treated with the 21-aminosteroid may be explained, at least in part, by reduced levels of proinflammatory stimuli such as lipid peroxidation, TNF-alpha and COX-2. Membrane stabilization may also, by reducing lipid peroxidation, play an additional role in preventing liver injury.

The effect and management of delayed vasospasm after aneurysmal subarachnoid hemorrhage.

Delayed cerebral vasospasm after aneurysm rupture is one of the major complications of subarachnoid hemorrhage. The purpose of this review was to determine the true incidence of vasospasm. All literature on cerebral aneurysms from 1960 onwards was reviewed, and the figures extracted from publications that mentioned vasospasm. Angiographic vasospasm, where patients were studied at the time of peak incidence, was reported in about two thirds of cases. Symptomatic vasospasm or delayed ischemia affects about one third. Untreated, nearly a third of those with ischemic deficits die and a similar proportion are left permanently disabled. Variations of Triple-H (hypervolemia, hypertension, hemodilution) therapy, used early after hemorrhage for prophylaxis of vasospasm, are associated with a decrease of nearly half in the incidence of delayed ischemia. When used as therapy outcome also appears better, with a reduction particularly in the death rate. Calcium antagonists have been widely used, especially nimodipine. In several controlled trials the incidence of delayed ischemia was significantly reduced. More importantly, the overall outcome of all subarachnoid hemorrhage patients was better with nimodipine prophylaxis. The 21-aminosteroid tirilazad mesylate has been the subject of several trials. In one the overall outcome of all patients was improved, but the effect was essentially in males only. Further studies with larger doses in females are being analyzed.

A randomized, double-blind, vehicle-controlled trial of tirilazad mesylate in patients with aneurysmal subarachnoid hemorrhage: a cooperative study in North America.

To test the safety and efficacy of tirilazad mesylate, a nonglucocorticoid 21-aminosteroid, in improving the outcome of patients with aneurysmal subarachnoid hemorrhage (SAH), 902 patients were enrolled in a prospective randomized, double-blind, vehicle-controlled trial at 54 North American neurosurgical centers. Five patients were excluded prior to receiving any study drug. Of 897 patients who received at least one dose of study medication, 300 received a placebo containing a citrate vehicle, 298 received 2 mg/kg per day tirilazad, and 299 received 6 mg/kg per day tirilazad, all administered intravenously beginning within 48 hours of the SAH and continuing through 10 days posthemorrhage. All patients were also treated with orally administered nimodipine. At 3 months post-SAH, there were no significant differences (p < 0.025) among the groups with regard to mortality rate, favorable outcome on the Glasgow Outcome Scale, or employment status. During the first 14 days after the SAH, there were no significant differences among the groups in the incidence or severity of clinically symptomatic or angiographically identifiable cerebral vasospasm. Mortality data stratified by gender and neurological grade on admission (assessed according to a modified World Federation of Neurological Surgeons scale) demonstrated that the men with Grades IV to V had a 33% mortality rate in the vehicle group, 52% in the 2 mg/kg per day tirilazad group (p = 0.29), and 5% in the 6 mg/kg per day tirilazad group (p = 0.03). Tirilazad was well tolerated at both dose levels. Tirilazad mesylate at dosage levels of up to 6 mg/kg per day for 8 to 10 days following SAH did not improve the overall outcome in patients with aneurysmal SAH in this trial. The differences in the efficacy of tirilazad in this trial and a previously reported trial in Europe, Australia, and New Zealand, in which dosage levels of tirilazad of 6 mg/kg per day reduced mortality rates and increased good recovery, may be a result of differences in admission characteristics of the patients and/or differences in management protocols, including the use of anticonvulsant medications.

Effect of 21-aminosteroid on extracellular energy-related metabolites and amino acids after compression injury of rat spinal cord.

We evaluated in a rat model of severe spinal cord compression the effect of the 21-aminosteroid tirilazad on extracellular levels of energy metabolites and amino acids, until 3 h after injury. The compound was given i.v. 30 min before injury (3 mg/kg) and hourly thereafter (1.5 mg/kg). The findings were compared with previously reported effects of methylprednisolone. Both treated and untreated rats with spinal cord compression showed, at 10 min after injury, a five- to sixfold elevation of extracellular lactate above the preinjury level. There was no significant difference for lactate, pyruvate or lactate/pyruvate ratio between the treated and untreated injured groups at any time point after trauma. Glutamate was significantly elevated both in treated and untreated injured rats for 20 min after trauma. The mean glutamate level was lower in animals treated with 21-aminosteroid. However, there was no statistically significant difference between the treated and untreated rats at any time after trauma. There was no statistically significant difference between the groups for aspartate, serine, glutamine, histidine, glycine, threonine, taurine, alanine and tyrosine. In conclusion our findings indicate that, in the injured spinal cord, methylprednisolone and the 21-aminosteroid have differences and similarities, regarding their effects on energy and amino acid metabolism. The lowering of the lactate and arginine levels early after trauma seen with methylprednisolone pretreatment was absent after 21-aminosteroid pretreatment. However, the mean extracellular level of glutamate was lower with both methylprednisolone and 21-aminosteroid after injury, although the difference was not statistically significant between treated and untreated rats.