Intrathecal edaravone, a free radical scavenger, is effective on inflammatory-induced pain in rats

BACKGROUND

Free radicals have some roles in inflammation and systemic and local tissue injuries. (Free radical scavengers are neuroprotective against excitotoxic insults.) Therefore, we hypothesized that free radical scavenger would be analgesic on pain induced by excitotoxicity or inflammation. The purpose of this study was to investigate analgesic effects of intrathecally administered edaravone, a free radical scavenger, on thermal and inflammatory pain.

METHODS

Sprague-Dawley rats were implanted with lumbar intrathecal catheters. Edaravone 0.05, 0.1, 0.5, and 1 mg per 20 microl or saline 20 microl (control) were administered intrathecally, and the withdrawal response to thermal stimulation to the tail (tail-flick test) or flinch responses to subcutaneous formalin injection into the hind paw (formalin test) were tested. General behaviour and motor function were also examined. In each dose group, eight rats were used.

RESULTS

No dose-dependent analgesic effects were observed in the tail-flick test. However, dose-dependent analgesia was obtained in both phase 1 and 2 of the formalin test. The 50% effective dose values were 0.25 mg (95% confidence interval, 0.11-0.56 mg) in phase 1 and 0.25 mg (95% confidence interval, 0.061-1.05 mg) in phase 2. No behavioural side-effects nor motor dysfunction was observed, even with the maximum soluble dose (1 mg/20 microl).

CONCLUSION

Intrathecally administered edaravone, a free radical scavenger, had analgesic effects on inflammatory-induced acute and facilitated pain but not on acute thermal pain, without any behavioural side-effects.

Montelukast, a Cysteinyl Leukotriene Receptor-1 Antagonist, Dose- and Time-Dependently Protects against Focal Cerebral Ischemia in Mice

Our previous studies showed that cysteinyl leukotriene receptor-1 (CysLT1) antagonist pranlukast has a neuroprotective effect on cerebral ischemia in rats and mice. However, whether the neuroprotective effect of pranlukast is its special action or a common action of CysLT1 receptor antagonists remains to be clarified. This study was performed to determine whether montelukast, another CysLT1 receptor antagonist, has the neuroprotective effect on focal cerebral ischemia in mice, and to observe its dose- and time-dependent properties. Permanent focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). Montelukast was injected intraperitoneally either as multiple doses (once a day for 3 days and 30 min before MCAO) or as a single dose (at 30 min before, 30 min after, or 1 h after MCAO), respectively, and pranlukast and edaravone were used as controls. The neurological deficits, infarct volumes, brain edema, neuron density, and Evans blue extravasation in the brain were determined 24 h after MCAO. Pretreatments with multiple doses or a single dose of montelukast (0.1 and 1.0 mg/kg) before MCAO significantly attenuated all the ischemic insults. Post-treatment with a single dose of montelukast (0.1 and 1.0 mg/kg) at 30 min after MCAO also significantly decreased brain edema and infarct volume, but not neurological deficits. However, post-treatment with a single dose of montelukast at 1 h after MCAO had no significant effect. Pranlukast showed the same effects as montelukast, but edaravone attenuated the ischemic insults only with multiple doses before MCAO. Thus, montelukast has a dose- and time-dependent neuroprotective effect on permanent focal cerebral ischemia in mice, with an effective dose range of 0.1-1.0 mg/kg and a therapeutic window of 30 min. These findings further support the therapeutic potential of CysLT1 receptor antagonists in the treatment of cerebral ischemia at earlier phases.

EPR imaging to estimate the in vivo intracerebral reducing ability of mature rats after neonatal hypoxic–ischemic brain injury

A rat model of neonatal hypoxic-ischemic encephalopathy (Rice's model) was obtained by unilateral ligation of the common carotid artery of 7-day-old rats with hypoxia (exposure to 8% oxygen). To estimate the in vivo intracerebral reducing ability of the mature rats (8 weeks old) of Rice's model, temporal electron paramagnetic resonance (EPR) imaging of the brain of a rat receiving a blood-brain barrier-permeable nitroxide radical, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, was performed. In this imaging technique, the decay rate of the EPR signal intensity in a selected region of the brain is indicative of region-specific reducing ability. The effect of neonatal treatment of an antioxidant agent, 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186), after a hypoxic-ischemic insult was also tested. It was found that the reducing ability had been depleted in the contralateral hemisphere of Rice's model rats; this depletion was suppressed by administering MCI-186.

Pretreatment with the Free Radical Scavenger Edaravone Prevents Cerebral Hyperperfusion after Carotid Endarterectomy

OBJECTIVE:

Cerebral hyperperfusion syndrome after carotid endarterectomy (CEA) is a rare but potentially devastating complication. The purpose of the present study, which was not a randomized controlled trial but a case cohort study with historical control, was to determine whether pretreatment with a novel free radical scavenger, edaravone, could prevent occurrence of cerebral hyperperfusion after CEA.

METHODS:

Fifty patients with ipsilateral internal carotid artery stenosis (≥70%) underwent CEA with administration of edaravone before internal carotid artery clamping. Preoperative cerebral blood flow and cerebrovascular reactivity (CVR) to acetazolamide were assessed with single-photon emission computed tomography (SPECT). Cerebral blood flow also was measured immediately after CEA and on the 3rd postoperative day.

RESULTS:

Cerebral hyperperfusion (cerebral blood flow increase ≥100% compared with preoperative values) was revealed by SPECT performed immediately after CEA in only one patient (2%), who also exhibited reduced preoperative CVR. The incidence of post-CEA hyperperfusion as revealed by SPECT in the control group (51 CEA patients without administration of edaravone) was significantly higher (16%) (P= 0.0310, control versus treatment group). In addition, in a subgroup of patients with reduced preoperative CVR, the incidence of post-CEA hyperperfusion as revealed by SPECT in the edaravone group (7%) was significantly lower than that in the control group (67%) (P= 0.0029). Logistic regression analysis demonstrated that reduced preoperative CVR and absence of pretreatment with edaravone were significant independent predictors of post-CEA hyperperfusion as revealed by SPECT.

CONCLUSION:

Pretreatment with edaravone can prevent occurrence of cerebral hyperperfusion after CEA.

Edaravone inhibits acute renal injury and cyst formation in cisplatin-treated rat kidney

BACKGROUND

Although cis-diamminedichloroplatinum (II) (cisplatin) is an effective anticancer agent, its clinical use is highly limited predominantly due to its adverse effects on renal functions. The present work examined the therapeutic potential of edaravone, a free radical scavenger, for inhibiting cisplatin-induced renal injury.

METHODS

Edaravone, 3-methyl-1-phenyl-pyrazolin-5-one, was administrated intravenously at a dose of 30 mg/kg of body weight to male Wistar rats (200-220 g). After 30 min, cisplatin was injected intraperitoneally at a dose of 5 mg/kg of body weight. At the indicated times after the treatment, functions and histological changes of the kidney were analyzed. To test the therapeutic potential of edaravone in chemotherapy, its effect on the anticancer action of cisplatin was examined in ascites cancer-bearing rats.

RESULTS

We found that cisplatin rapidly impaired the respiratory function and DNA of mitochondria in renal proximal tubules, thereby inducing apoptosis of tubular epithelial cells within a few days and chronic renal dysfunction associated with multiple cysts one-year after the administration. Administration of edaravone inhibited the cisplatin-induced acute injury of mitochondria and their DNA and renal epithelial cell apoptosis as well as the occurrence of chronic renal dysfunction and multiple cyst formation. The anticancer effect of cisplatin remained unaffected by intravenous administrating of edaravone.

CONCLUSIONS

These results indicate that edaravone may have therapeutic potential for inhibiting the acute and chronic injury of the kidney induced by cisplatin.

Effects of edaravone on reperfusion injury in patients with acute myocardial infarction

This clinical pilot study was a randomized, controlled, open-label study in 80 patients with acute myocardial infarction and was designed to examine the effects of a novel free radical scavenger, edaravone. Administration of edaravone before myocardial reperfusion was associated with smaller enzymatic infarcts and better clinical outcome.

A new free radical scavenger, edaravone, ameliorates oxidative liver damage due to ischemia-reperfusion in vitro and in vivo

Ischemia-reperfusion injury causes oxidative stress producing reactive oxygen species, which is a serious problem linked to morbidity and mortality in liver surgery. We investigated the effects of edaravone, a new free radical scavenger, on liver oxidative stress in vitro and in vivo. We employed a hypoxia-reoxygenation model of primary cultured hepatocytes using an AnaeroPack (Mitsubishi Gas Chemical Co., Tokyo, Japan). Hepatocytes were exposed to 3 or 4 hours of hypoxia and then returned to oxygenation. We analyzed the time course changes of aspartate aminotransferase (AST), phosphatidylcholine hydroperoxide (PCOOH), and adenosine triphosphate (ATP) content in hepatocytes of edaravone-treated groups or nontreated groups after reoxygenation. Edaravone significantly attenuated the elevation of the AST level of the medium and hepatocellular PCOOH and preserved the hepatocellular ATP level. In vivo, male Sprague-Dawley rats were subjected to 45 minutes of hepatic ischemia and 120 minutes of reperfusion. The rats were intravenously injected with vehicle or edaravone (3 mg/kg or 10 mg/kg) before reperfusion and 1 hour after reperfusion. Serum AST levels and hepatic PCOOH and energy charge were significantly improved in both edaravone groups compared with control. In conclusion, edaravone has the ability to eliminate intra-hepatocellular superoxide species and attenuate oxidative liver damage in liver surgery.

MCI-186 reduces oxidative cellular damage and increases DNA repair function in the rabbit spinal cord after transient ischemia

BACKGROUND

Paraplegia is a serious complication of operations on the thoracic and thoracoabdominal aorta. To investigate the mechanism by which motor neurons are damaged during these operations, we have reported a rabbit model of spinal cord ischemia. We also tested whether a free radical scavenger MCI-186 that is useful for treating ischemic damage in the brain can protect against ischemic spinal cord damage.

METHODS

Fifteen minutes of ischemia was induced, then MCI-186 or vehicle was injected intravenously. Cell damage was analyzed by observing the function of the lower limbs and by counting the number of motor neurons. To investigate the mechanism by which MCI-186 prevents ischemic spinal cord damage, we observed the immunoreactivity of 8-hydroxy-2'-deoxyguanosine as an oxidative DNA damage marker and redox effector as a DNA repair marker.

RESULTS

In sham control, 8-hydroxy-2'-deoxyguanosine was not observed, and the nuclear expression of redox effector was observed. In vehicle injection group (group I), the nuclear expression of 8-hydroxy-2'-deoxyguanosine was observed at 1 and 2 days after reperfusion. The nuclear expression of redox effector was observed at 8 hours and 1 day, and disappeared at 2 days after transient ischemia. In MCI-186 injection group (group M), the nuclear expression of 8-hydroxy-2'-deoxyguanosine was not observed, and redox effector was observed at 8 hours and 1 and 2 days.

CONCLUSIONS

These results suggest that redox effector decreased in motor neurons after transient ischemia and this reduction preceded oxidative DNA damage. MCI-186 works as a radical scavenger and reduced oxidative DNA damage, so redox effector did not disappear. MCI-186 could be a strong candidate for a use as a therapeutic agent in the treatment of ischemic spinal cord injury.

Neuroprotection of edaravone on hypoxic-ischemic brain injury in neonatal rats

Edaravone has an inhibitory effect on lipid peroxidation by scavenging free radicals and prevents vascular endothelial cell injury. We examined whether edaravone was effective on hypoxic-ischemic (HI) brain injury in immature brain or not using the Rice-Vannucci model. The initial dose, 3 mg/kg (0.05 ml) of edaravone, was injected intraperitoneally just before hypoxic exposure. Subsequently, the same dose was injected every 12 h until the animals were killed. Controls received saline injection as the same protocol. Macroscopic evaluation of brain injury revealed that the neuroprotective effect of edaravone on HI brain after 48 h post HI. TUNEL showed that edaravone injection decreased neurodegeneration. Quantitative analysis of cell death using H&E-stained 2.5 microm sections showed that there was a trend for both necrotic and apoptotic cells to decrease in edaravone injection group. Edaravone injection inhibited the release of cytochrome c from mitochondria to cytosol and caspase-3 activation in cortex and hippocampus between 24 and 168 h post HI. Our results suggest that edaravone is protective after HI insult in the immature brain by decreasing both apoptosis and necrosis and also by inhibiting mitochondrial injury.

Free radical scavenger, edaravone, in stroke with internal carotid artery occlusion

BACKGROUND

Edaravone has potent free radical quenching and antioxidant actions. The agent has been recently in commercial use for acute ischemic stroke patients. In this study, we investigated the therapeutic effect of edaravone on severe carotid-territorial stroke.

METHODS

Stroke patients with internal carotid artery occlusion and baseline NIH Stroke Scale Score > or =15 were treated for 14 days with drip intravenous infusion of edaravone (n=30) and were compared with a historical control cohort of similar patients (n=31). Glycerol was also administered to all patients in both groups.

RESULTS

Infarct volume (P<0.02) and midline shift (P<0.02) on CT performed on day 2 of the patients treated with edaravone were smaller than those without edaravone. For patients with edaravone, infarct volume (P<0.0001) and midline shift (P<0.0001) on days 5-7 were greater than those on day 2. Hemorrhagic transformation of infarcts on day 2 was less severe in patients with than without edaravone (P<0.03). Within 14 days after the onset of stroke, 6 patients with edaravone (20%) and 14 without edaravone (45%) died directly of stroke (P<0.03). Among all patients, only two treated with edaravone were independent without any assistance 8 weeks after the onset.

CONCLUSIONS

Edaravone was associated with delayed evolution of infarcts and edema in patients with severe carotid-territorial stroke and decreased mortality during the acute stage. The agent, however, failed to prevent evolution of infarcts and edema on later days, and did not significantly improve functional outcome among the surviving patients.

[Research and development of the free radical scavenger edaravone as a neuroprotectant]

Increasing data suggest that oxygen free radical species play detrimental roles in ischemic diseases. A free radical scavenger capable of inhibiting oxidative injury is expected to become a new drug for the treatment of ischemic diseases such as cerebral ischemia. Edaravon (3-methyl-1-phenyl-2-pyrazolin-5-one), which has been developed as an neuroprotective agent for more than 15 years since its discovery, is approved for the treatment of acute cerebral infarction. In this paper, the pharmacologic characteristics and clinical effects of edaravone are reviewed. In early stage of investigation, edaravone was found to have promising activities as an antioxidative radical scavenger, quenching hydroxyl radical (.OH) and inhibiting both .OH-dependent and .OH-independent lipid peroxidation. Edaravone showed inhibitory effects on both water-soluble and lipid-soluble peroxyl radical-induced peroxidation systems, which are different from the inhibitory effects of vitamins C and E in each system, respectively. Oxidative injury to cultured endothelial cells caused by arachidonate (AA) peroxides is prevented in the existence of edaravone. To clarify the characteristics of this free radical scavenger, further investigation was carried out. Edaravone ameliorated exacerbation of cortical edema induced by a focal ischemia-reperfusion model in rats, suggesting inhibitory effects on oxidative injury to the blood-brain barrier (BBB). Additionally, edaravone also prevented rat cortical edema caused by intracortical AA infusion in which free radical production and subsequent oxidative injury to the BBB are involved. With advances in in vivo measurement technology of oxygen radicals, edaravone was shown to inhibit postischemic increases in .OH production and tissue injury in the penumbral or recirculated area in rat cerebral ischemia models. In clinical studies, edaravone improved the core neurologic deficits, activities of daily living, and functional outcome of stroke patients. Furthermore, a study using proton magnetic resonance spectroscopic techniques showed that edaravone preserved N-acetyl-aspartate in stroke patients, a promising neuronal marker in the brain. Further investigation is essential for a better understanding of free radical-mediated cerebral injury during ischemia followed by recirculation. We hope that edaravone represents a promising neuroprotectant for drug therapy in acute cerebral ischemia.

Tetracycline compound placement to prevent dry socket: a postoperative study of 200 impacted mandibular third molars

PURPOSE

Our objective was to study whether the placement of intra-alveolar tetracycline prevents dry sockets or improves the postoperative period.

PATIENTS AND METHODS

A comparative clinical study of the surgical removal of 200 impacted mandibular third molars is made, with particular reference to postextraction pain, inflammation, trismus, and the incidence of dry socket. In 50% of these cases, a pharmacologic preparation that includes tetracycline was placed in the socket after removal of the impacted molar.

RESULTS

Dry socket was diagnosed in 4 cases (2%), with no relation to intra-alveolar tetracycline placement being observed. The patients who were administered intra-alveolar tetracycline had less pain and trismus and consumed fewer analgesics than the patients who received no such treatment, although statistical significance was not reached.

CONCLUSIONS

The intra-alveolar placement of tetracycline compound after the surgical removal of impacted mandibular third molars did not affect the incidence of dry socket.

Edaravone Protects against Hypoxia/Ischemia-Induced Endoplasmic Reticulum Dysfunction

Endoplasmic reticulum (ER) stress-induced cell death plays an important role in cerebral ischemia. In the present study, we investigated whether edaravone (3-methyl-1-phenyl-pyrazolin-5-one), a free radical scavenger, can protect against ER damage induced by cerebral ischemia. In a mouse model of hypoxia/ischemia, treatment with edaravone reduced edema-corrected infarction volume, attenuated hemispheric swelling, and improved neurological status. Moreover, edaravone suppressed ER stress-mediated apoptosis by inhibiting eukaryotic initiation factor alpha phosphorylation, C/EBP homologous protein (CHOP) induction, and caspase-12 activation. In mouse primary cultured glial cells, edaravone attenuated ER stress as evidenced by inhibition of the induction of glucose regulated protein 78 and CHOP and XBP-1 splicing under treatment with tunicamycin (Tm), which induces ER stress. Tm did not induce the production of reactive oxygen species in primary cultured glial cells. In addition, the free radical scavengers N-acetyl-l-cysteine and ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] did not affect ER stress response caused by Tm. These results demonstrated a novel action of edaravone that can protect against ER dysfunction in cerebral ischemia.

The hydroxyl radical scavenger MCI-186 protects the liver from experimental cold ischaemia-reperfusion injury

BACKGROUND

Oxidative stress contributes to hepatic ischaemia-reperfusion (IR) injury in a biphasic pattern. In addition to direct cytotoxic effects, oxidative stress also initiates the signal transduction processes that promote second-phase liver injury. The present study investigated the effects of the hydroxyl radical scavenger MCI-186 on the biphasic process of hepatic cold IR injury.

METHODS

After cold preservation for 16 h, rat livers were reperfused on an isolated liver perfusion system for 120 min with oxygenated Krebs-Henseleit bicarbonate buffer. Perfusate samples were obtained serially, and portal flow rates were also recorded. To determine whether MCI-186 affected cytokine levels that control the second-phase injury, levels of interleukin (IL) 10 and tumour necrosis factor (TNF) alpha were measured in the perfusate.

RESULTS

Addition of MCI-186 1 mg/l into the perfusate significantly improved portal flow (P<0.050), hepatic enzyme release into the perfusate (P=0.038), total bile production (P=0.029) and malondialdehyde concentration (P=0.038). Furthermore, treatment with MCI-186 led to a substantial increase in IL-10 release (P=0.032). TNF-alpha levels were not affected.

CONCLUSIONS

MCI-186, an agent ready for clinical use, appears to have direct and indirect protective effects against hepatic cold IR injury.

Free radical scavenger protects against inner hair cell loss after cochlear ischemia

We investigated the protective effects of edaravone, a free radical scavenger, against ischemic damage of inner hair cells (IHCs) in gerbils. Cochlear ischemia was induced in the animals by occluding the vertebral arteries bilaterally for 15 min. Edaravone (1 mg/kg, i.v.) or saline was administered 1 h after ischemia. Hearing was assessed by auditory brain response (ABR). In animals treated with saline, the ABR threshold shift was 24.1 dB and there was a 26.5% decrease in the number of IHCs. By contrast, in animals treated with edaravone, the threshold shift was 7.5 dB and only 8.8% of IHCs was lost. These results suggest that edaravone protects against damage to the inner ear following transient ischemia.

[Gene therapy and neuroprotection for cerebral infarction]

Topical application of GDNF protein greatly reduced the infarct size and brain edema at 24 hr of continuous MCAO in rats. The reduction of the infarct size was not related to a change of cerebral blood flow (CBF), but was accompanied by marked reduction of positive cells for TUNEL and caspases in the affected area. GDNF protein showed a direct protective effect against ischemic brain damage, but not secondary by improving CBF. Pretreatment of animals with Ad-GDNF 24 hr before the subsequent 90 min of transient MCAO effectively reduced infract volume and area without affecting regional CBF compared to the vehicle or Ad-LacZ animal groups. Free radical scavenger edaravone effectively reduced brain edema, infarct size, and peroxidative markers of protein, lipid and DNA. Thus, gene therapy and neuroprotective strategy have a great potential for reducing ischemic brain damage of human stroke patients in the near future.

[Advances in the diagnosis and treatment of cerebral ischemia during the acute phase]

Recent advances in MRI technology and the development of effective neuroprotective agents has improved the outcome of stroke. In order to salvage tissue after an ischemic insult it is important to differentiate the core and penumbra area of the ischemic lesion. The penumbra surrounds the ischemic core, damage in this area is reversible if effective neuroprotective agents are given and reperfusion occurs. In this symposium detection of penumbra in an ischemic lesion using diffusion weighted imaging (DWI) and perfusion imaging (PI), diffusion-perfusion mismatch, and indications for thrombolytic therapy are discussed. If a hypoperfusion area is revealed with PI without a corresponding lesion indicated with DWI or when the DWI lesion is less than one third of the PI lesion, combined thrombolytic and neuroprotective therapies are recommended. In contrast, when both PI and DWI show an identical lesion, only neuroprotective therapy is advised. Additionally, newly developed neuroprotective agents, especially the combined effect of rt-PA and the immunosuppressant, FK506, on an embolic infarct model are discussed.

Edaravone, a novel free radical scavenger, prevents liver injury and mortality in rats administered endotoxin

We postulated that a novel free radical scavenger, 3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone; EDA), would attenuate inflammatory cytokine and chemokine expression in the liver after lipopolysaccharide (LPS) challenge through its antioxidant effect. Rats were administered EDA (0.3, 1.5, 3.0, 6.0, and 12.0 mg/kg) or the same volume of saline intravenously just after LPS (10 mg/kg) injection and then was continued intermittently every 2 h (five administrations in total). Survival was assessed for the next 24 h. In separate experiments, rats were sacrificed at 60 min, 90 min, 6 h, and 9 h after LPS injection. Serum and liver sections were collected for further analysis. Survival was improved by EDA in a dose-dependent manner up to 3 mg/kg, and maximum effects were observed at a dose of 3 mg/kg. After LPS injection, alanine aminotransferase levels increased significantly to about 1,250 IU/l in the vehicle-treated group, whereas values were blunted by about 80% by EDA. Furthermore, increases in 4-hydroxynonenal-modified proteins were also blunted in the liver by EDA. Moreover, mRNA expressions of macrophage infiltrating protein-2, monocyte chemoattractant protein (MCP)-1 and MCP-5 were attenuated by EDA. As a result, increases in the number of infiltrating inflammatory cells and mRNA expression of inflammatory cytokines such as tumor necrosis factor-alpha and interleukin-6 were significantly blunted in the liver by EDA. This reduction was accompanied by a significant reduction of their serum levels. In conclusion, EDA prevented liver injury by both inhibition of recruitments of inflammatory cells and expression of inflammatory cytokine levels in the liver.

[Current aspects of the treatment of migraine]

In the article, an analysis is performed of the published literature focusing on the pathogenesis and current approaches to the management of migraine. It shows results of clinical approbation of nomigren, a new combined drug, in 72 patients presenting with different forms of migraine.

Effect of a novel free radical scavenger, edaravone (MCI-186), on acute brain infarction. Randomized, placebo-controlled, double-blind study at multicenters

Edaravone, a novel free radical scavenger, demonstrates neuroprotective effects by inhibiting vascular endothelial cell injury and ameliorating neuronal damage in ischemic brain models. The present study was undertaken to verify its therapeutic efficacy following acute ischemic stroke. We performed a multicenter, randomized, placebo-controlled, double-blind study on acute ischemic stroke patients commencing within 72 h of onset. Edaravone was infused at a dose of 30 mg, twice a day, for 14 days. At discharge within 3 months or at 3 months after onset, the functional outcome was evaluated using the modified Rankin Scale. Two hundred and fifty-two patients were initially enrolled. Of these, 125 were allocated to the edaravone group and 125 to the placebo group for analysis. Two patients were excluded because of subarachnoid hemorrhage and disseminated intravascular coagulation. A significant improvement in functional outcome was observed in the edaravone group as evaluated by the modified Rankin Scale (p = 0.0382). Edaravone represents a neuroprotective agent which is potentially useful for treating acute ischemic stroke, since it can exert significant effects on functional outcome as compared with placebo.

Drug-induced hepatitis with hepatic granuloma due to saridon

A 38-year-old Japanese woman with no past history of liver disease developed liver dysfunction associated with fever, anorexia, and general malaise following the prolonged administration of saridon. A liver biopsy demonstrated multiple noncaseating epithelioid granulomas within hepatic lobules, with an inflammatory cell infiltrate of the lobular parenchyma and portal tracts. Viral markers and autoantibodies were negative. Lymphocyte stimulation tests for saridon and for isopropylantipyrine, one of the constituents of saridon, were positive, and therefore a diagnosis of drug-induced hepatitis due to administration of saridon was made. Her symptoms resolved and liver function test results returned to normal following discontinuation of the drug. The possibility of drug-induced hepatitis must be considered when liver dysfunction or systemic symptomatology develops during saridon therapy.

Contractile responses to reactive oxygen species in the canine basilar artery in vitro: selective inhibitory effect of MCI-186, a new hydroxyl radical scavenger

BACKGROUND

Cerebral vasospasm is one of the important pathological phenomena which influence morbidity and mortality following subarachnoid haemorrhage. Reactive oxygen species (ROSs) generated by the autoxidation of oxyhemoglobin to methemoglobin may be one of the essential factors in the pathogenesis of cerebral vasospasm. The direct vasocontractile effects of hydrogen peroxide (H(2)O(2)), superoxide anion (O(2)(-)), and hydroxyl radical (*OH) on the canine basilar artery and the inhibitory effects of MCI-186 (3-methyl-1-phenyl-2-pyrazolin-5-one), a new *OH scavenger, were investigated.

METHOD

Isometric tension was recorded in basilar artery rings from dogs in vitro. H(2)O(2), pyrogallol (O(2)(-) donor), and vitamin C (VitC)/Fe(2+) (*OH-generating system) were used to generate the ROSs.

FINDINGS

H(2)O(2) (10 micromol/L), pyrogallol (10 micromol/L), and VitC/Fe(2+) (100 micromol/L each) induced fast onset and transient, slow onset and transient, and sustained contraction, respectively, in the canine basilar artery. Contractions induced by H(2)O(2) were almost completely inhibited by pre-incubation with catalase (800 U/mL) and those by pyrogallol with superoxide dismutase (150 U/mL), but neither with MCI-186 (10 micromol/L). The contraction induced by VitC/Fe(2+) was clearly inhibited by pre-incubation with MCI-186, but not with catalase or superoxide dismutase.

INTERPRETATION

ROSs have direct vasocontractile effects on the canine basilar artery in vitro, but different ROSs have different contractile characteristics. Such contractions might be related to the pathophysiology of cerebral vasospasm. MCI-186 had a clear and selective inhibitory effect against *OH-induced contraction in vitro. Comparison of different radical scavengers may be important in pharmacological assessment, especially targeted on cerebral vasospasm.

Beneficial effect of MCI-186 on hepatic warm ischemia-reperfusion in the rat

Despite growing evidence that reactive oxygen species are responsible for deleterious effects of ischemia-reperfusion (I/R) injury of the liver, there exists, until now, no reliable antioxidant therapeutics applicable in the clinical setting. We investigated the effects of free radical scavenger, 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186), using an isolated liver perfusion model to elucidate its possible therapeutic effects on hepatic warm I/R injury. Isolated livers from Wistar rats were reperfused for 120 min with an oxygenated Krebs-Henseleit bicarbonate buffer after 1 hr of warm ischemia. Addition of MCI-186 (1 mg/L) into the perfusate significantly improved portal flow, hepatic enzyme release into the perfusate, total bile production, histologic alteration, and malondialdehyde concentration but not sinusoidal endothelial cell function as assessed by the clearance of hyaluronic acid. MCI-186 seems to have protective effects against hepatic warm I/R injury by attenuating the damage of the hepatocyte, which is the major target of oxidative damage in this model.

Myocardial protection of MCI-186 in rabbit ischemia-reperfusion

We observed that 3-methyl-1-1phenyl-2-pyrazolin-5-one (MCI-186), a newly-developed free radical scavenger, attenuated necrosis in the in vivo rabbit hearts upon reperfusion after prolonged ischemia. In rabbits undergoing 1 hour ligation of the anterior ventricular coronary artery, a single bolus injection of MCI-186 (1.5 mg/kg) was introduced into the post-ischemic heart immediately before 4 hour reperfusion. Compared to negligible necrosis in sham-operated control animals and 33.81 +/- 13.50% necrosis in the area at risk for the saline control group (n = 8), the MCI-186 - treated group (n = 8) had a necrosis of 13.27 +/- 4.60% (p < 0.05 vs saline control group). The pressure-rate index had a slight decrease in MCI-186 treated group compared to the control group (p > 0.05). However, the blood levels of malondialdehyde (MDA) in MCI-186 treated group (2.08 +/- 0.23 microM) was significantly smaller than that of 2.65 +/- 0.31 microM in control animals (p < 0.01), while sham control had an average MDA level of 1.91 +/- 0.40 microM, with p > 0.05 relative to that in the MCI-186 treated group. These data support our contention that MCI-186 reduces reperfusion injury in perfused hearts with prolonged ischemia and the mechanism for the in vivo efficacy of MCI-186 is predominantly related to its antioxidant activities.