Biomedical subjects

W M Clark

Publications and source records attributed to W M Clark.

At least 19 recordsLinked to original sources

PubMed2001

A phase III randomized efficacy trial of 2000 mg citicoline in acute ischemic stroke patients.

BACKGROUND: Citicoline may reduce CNS ischemic injury by stabilizing cell membranes and reducing free radical generation. Previous safety and efficacy trials in patients who have had acute strokes suggested that citicoline may improve neurologic outcome with minimal side effects. OBJECTIVE: To determine the safety and efficacy of citicoline treatment in acute stroke patients. METHOD: An 118-center, randomized, double-blind, efficacy trial in 899 patients compared placebo (n = 446) with citicoline (n = 453) (1000 mg PO twice a day) for 6 weeks, with a 6-week post-treatment follow-up period. Patients with acute (< or =24 hours) ischemic strokes clinically thought to be in the middle cerebral artery territory with NIH Stroke Scale (NIHSS) scores > or =8 were enrolled. RESULTS: Mean time to treatment was 13 hours for both groups and mean age was 67 years for those receiving placebo and 68 years for those receiving citicoline. Mean baseline NIHSS scores were 14.5 for placebo and 13.9 for citicoline (p = 0.06); medians were 14 for placebo and 13 for citicoline (p = 0.04). The incidence and type of side effects were similar between the groups. There were no between-group differences on the planned primary analysis, percent of patients with a > or =7-point NIHSS score change at 90 days (placebo 51%, citicoline 52%). There were no between-group differences on the other planned secondary analyses at 90 days, including mortality. However, post hoc analyses using standard "excellent recovery" measures suggested a possible treatment effect on the modified Rankin 0 or 1 (last observation carried forward: placebo 20%, citicoline 26%; p = 0.025) as well as a global outcome statistic. CONCLUSIONS: Citicoline was safe but ineffective in improving the outcome of patients with acute ischemic stroke as measured by the planned analyses. Post hoc analyses suggest that a modest treatment effect may have been seen if more traditional analyses had been used.

Acute Disease↗

PubMed2001

Current status of neuroprotective agents in the treatment of acute ischemic stroke.

To keep ischemic brain cells alive, neuroprotective agents target events in the ischemic cascade that might be injurious to the cells. They can be divided broadly into groups that restore ion balance, block receptors, prevent reperfusion injury, or promote neuronal healing. To date, neuroprotective agents have either shown a lack of efficacy in clinical stroke trials or been limited by side effects. Ongoing clinical trials with novel agents are trying to enroll a more homogeneous population of stroke patients in an effort to demonstrate treatment benefit.

Acute Disease↗

PubMed2001

Efficacy of antioxidant therapies in transient focal ischemia in mice.

BACKGROUND AND PURPOSE: Ginkgo biloba extract (EGb) and alpha-lipoic acid (LA) are commercially available "antioxidant supplements" with a variety of actions that may be beneficial during acute stroke. These actions include inhibiting platelet and leukocyte activation and adhesion, reducing free radical generation, and increasing cerebral blood flow. Both EGb and LA have been shown to be neuroprotective in cell culture and global central nervous system ischemia models. In this study we investigated the neuroprotective efficacy of EGb and LA in a clinically relevant, transient focal central nervous system ischemic model. METHODS: In the EGb study, 60 adult C57blk mice were randomized to treatment with EGb given orally (via gavage) for 7 days: low dose, 50 EGb mg/kg daily; high dose, 100 mg/kg daily; matched placebo. On day 7, reversible middle cerebral artery occlusion was produced by advancing a silicone-coated 8-0 filament into the internal carotid artery for 45 minutes followed by reperfusion. At 24 hours, the animals were evaluated on a 28-point clinical scale, and infarct volume was determined with the use of triphenyltetrazolium chloride. In the LA study, 24 C57blk mice were treated with 100 mg/kg SC of LA or placebo 1.5 hours before transient MCAO, as in the EGb study. RESULTS: In the EGb study, values for infarct volume at 24 hours were as follows (mean+/-SD): low dose (n=18), 13+/-5 mm(3); high dose (n=22), 22+/-12 mm(3); placebo (n=20), 20+/-10 mm(3) (P:=0.03 overall; P=0.02, low dose versus placebo). Infarct percentage of hemisphere values were as follows: low dose, 14+/-5%; high dose, 21+/-11%; placebo, 20+/-9% (P=0.03 overall; P=0.02, low dose versus placebo). Ten percent of the high-dose group showed significant intracerebral hemorrhage (ICH) within the infarct, while no ICH was seen in the other groups. Neurological function scores were as follows: low dose, 11.8+/-1.5; high dose, 11.4+/-1.7; placebo, 11.3+/-1.8 (P=NS). In the LA study, infarct volume was as follows: 100 mg/kg LA (n=12), 16.8+/-8.3 mm(3); placebo (n=12), 27.2+/-14.6 mm(3) (P<0.05). LA also produced a significant improvement in neurological function at 24 hours: LA, 9.5+/-1.2; placebo, 11.2+/-1.8 (P=0.02). There was no evidence of ICH in any of the animals. CONCLUSIONS: Both oral EGb and LA therapies produced significant reductions in stroke infarct volume. However, for EGb this beneficial effect appears to be dose related, with higher doses potentially increasing the risk of ICH.

Administration, Oral↗

PubMed2001

Potential of anticytokine therapies in central nervous system ischaemia.

Central nervous system (CNS) ischaemia is associated with an acute inflammatory response which appears to potentiate CNS injury, especially following reperfusion. This response includes the release of inflammatory mediators called cytokines including IL-1 and TNF-alpha, which triggers the production of additional cytokines including IL-6 and activates leukocytes which infiltrate into the CNS. Increased expression of cytokines has been demonstrated to occur in the first few hours after CNS ischaemia. Preliminary clinical studies suggest that plasma levels of IL-6 are correlated with functional recovery while brain levels of cytokines have been demonstrated to increase following experimental ischaemia. Although there are no current clinical 'anti-cytokine' treatment studies for stroke, experimental studies modulating IL-1 and TNF-alpha have shown neuroprotection.

Animals↗

PubMed2000

Association of intracranial stenosis with cortical symptoms or signs.

The association of the presence of cortical symptoms or signs and anterior circulation intracranial stenosis in patients with anterior circulation ischemia and no known extracranial carotid or cardiac etiology was studied. Fifteen percent (5/33) of patients with cortical symptoms or signs had symptomatic intracranial stenosis of 50% or more by MR angiography or angiography, compared with 0% (0/15) of those without such findings (p < 0.005).

Aged↗

PubMed2000

Intravenous tissue-type plasminogen activator for treatment of acute stroke: the Standard Treatment with Alteplase to Reverse Stroke (STARS) study.

CONTEXT: Tissue-type plasminogen activator (tPA) is the only therapy for acute ischemic stroke approved by the Food and Drug Administration. OBJECTIVE: To assess the safety profile and to document clinical outcomes and adverse events in patients treated with intravenous tPA for acute stroke in clinical practice. DESIGN AND SETTING: Prospective, multicenter study of consecutive patients enrolled between February 1997 and December 1998 at 57 medical centers in the United States (24 academic and 33 community). INTERVENTION: Intravenous tPA (recombinant alteplase). PATIENTS: Three hundred eighty-nine patients with a mean age of 69 years (range, 28-100 years); 55% were men. MAIN OUTCOME MEASURES: Time intervals between stroke symptom onset, hospital arrival, and treatment with tPA; pretreatment computed tomographic scan results, intracerebral hemorrhage, and major systemic bleeding. The modified Rankin Scale score was used to assess clinical outcomes at 30 days. RESULTS: Median time from stroke onset to treatment was 2 hours 44 minutes, and the median baseline National Institutes of Health Stroke Scale score was 13. The 30-day mortality rate was 13%. At 30 days after treatment, 35% of patients had very favorable outcomes (modified Rankin score, 0-1) and 43% were functionally independent (modified Rankin score, 0-2). Thirteen patients (3.3%) experienced symptomatic intracerebral hemorrhage, including 7 who died. Twenty-eight patients (8.2%) had asymptomatic intracerebral hemorrhage within 3 days of treatment with tPA. Protocol violations were reported for 127 patients (32.6%), and included treatment with tPA more than 3 hours after symptom onset in 13.4%, treatment with anticoagulants within 24 hours of tPA administration in 9.3%, and tPA administration despite systolic blood pressure exceeding 185 mm Hg in 6.7%. A multivariate analysis found predictors of favorable outcome to be a less severe baseline National Institutes of Health Stroke Scale score, absence of specific abnormalities (effacement or hypodensity of >33% of the middle cerebral artery territory or a hyperdense middle cerebral artery) on the baseline computed tomographic scan, an age of 85 years or younger, and a lower mean arterial pressure at baseline. CONCLUSIONS: This study, conducted at multiple institutions throughout the United States, suggests that favorable clinical outcomes and low rates of symptomatic intracerebral hemorrhage can be achieved using tPA for stroke treatment.

Adult↗

PubMed2000

The rtPA (alteplase) 0- to 6-hour acute stroke trial, part A (A0276g) : results of a double-blind, placebo-controlled, multicenter study. Thromblytic therapy in acute ischemic stroke study investigators.

BACKGROUND AND PURPOSE: The Thrombolytic Therapy in Acute Ischemic Stroke Study, which started in August of 1991, was designed to assess the efficacy and safety of intravenous rtPA (alteplase) in patients with acute (0 to 6 hours) ischemic stroke. In October 1993 enrollment was halted because of Safety Committee (DMSB) concerns. In December 1993 the time window was changed to 0 to 5 hours, and it was decided to restart enrollment as a separate study (part B). We report here the results of the original study (part A), focusing on evaluating the safety and efficacy of rtPA given between 0 and 6 hours after stroke onset. METHODS: This investigation was a phase II, placebo-controlled, double-blind, randomized study utilizing 0.9 mg/kg IV rtPA or placebo over 1 hour, which was conducted at university and community sites in North America. Except for time to treatment, enrollment criteria were very similar to those of the NINDS rtPA stroke study. Primary efficacy end points were the number of patients with a decrease of 4 or more points on the National Institutes of Health Stroke Scale (NIHSS) at 24 hours and day 30, along with infarct volume at day 30. Secondary end points included mortality and functional recoveries on the Barthel Index and Modified Rankin scale at days 30 and 90. RESULTS: A total of 142 patients were enrolled at 42 sites in North America, including 22 <3 hours (15%) and 46 between 5 and 6 hours (32%). The groups were well matched on baseline characteristics, including NIHSS (mean of 13 for both). For the primary end points, a higher percentage of rtPA patients had a 4-point improvement at 24 hours (placebo 21%, rtPA 40%; P=0.02); however, this early effect was reversed by 30 days, with more placebo patients having a 4-point improvement (75%) than patients treated with rtPA (60%, P=0.05). Treatment with rtPA significantly increased the rate of symptomatic intracerebral hemorrhage within 10 days (11% versus 0%, P<0.01) and mortality at 90 days (23% versus 7%, P<0.01). CONCLUSIONS: This study found no significant rtPA benefit on any of the planned efficacy end points at 30 and 90 days in patients treated between 0 and 6 hours after stroke onset. These negative results apply to patients treated after 3 hours, because only 15% of the patients were enrolled before 3 hours. The risk of symptomatic intracerebral hemorrhage was increased with rtPA treatment, particularly in patients treated between 5 and 6 hours after onset. These results do not support the use of intravenous rtPA for stroke treatment >3 hours after onset.

Acute Disease↗

PubMed2000

Postischemic attenuation of cerebral artery reactivity is increased in the presence of tissue plasminogen activator.

BACKGROUND AND PURPOSE: We investigated the combined effect of tissue plasminogen activator and ischemia on middle cerebral artery (MCA) reactivity to determine whether abnormal MCA function after 2 hours of ischemia was worse in arteries perfused with recombinant tissue plasminogen activator (rtPA). METHODS: The intraluminal suture model of focal cerebral ischemia was used to induce 2 hours of ischemia in rats, after which occluded MCAs were removed and studied in vitro with an arteriograph system that allowed control of transmural pressure (TMP) and measurement of lumen diameter. Arteries were either nonischemic (control; n=8), nonischemic and perfused with 400 microg/mL rtPA (rtPA; n=5), ischemic (ISC; n=6), or ischemic and perfused with 400 microg/mL rtPA (ISC-rtPA; n=6). After a 1-hour equilibration at 75 mm Hg, TMP was increased to 125 mm Hg and lumen diameter was recorded at each pressure. Reactivity to acetylcholine (ACh, 0.1 to 10.0 micromol/L) and serotonin (0.01 to 10 micromol/L) was then determined. RESULTS: Control arteries responded myogenically to pressure and increased the amount of tone from 18.5+/-3.8% at 75 mm Hg to 24.8+/-3.0% at 125 mm Hg (P<0.05), which decreased diameter from 241+/-7 to 232+/-6 microm. In contrast, all other groups decreased tone at 125 mm Hg, which demonstrated a loss of myogenicity. The percent tone in each group at 75 versus 125 mm Hg was rtPA, 16.0+/-4.5% versus 11.8+/-3.8%; ISC, 23.5+/-4.5% versus 13. 5+/-3.1%; and ISC-rtPA, 23.5+/-4.2% versus 12.3+/-3.2% (P<0.05 for all). The percent increase in lumen diameter at each concentration of ACh was diminished in all groups compared with control; ISC-rtPA arteries responded the least, which suggests an additive effect of rtPA in ischemic arteries. The percent increase in lumen diameter at 10(-5)mol/L ACh was 23+/-4% for control versus 15+/-2% for rtPA; 17+/-3% for ISC arteries (P<0.05), and 8+/-2% for ISC-rtPA arteries (P<0.01). Sensitivity to serotonin was equally diminished in all groups compared with control: EC(50) (micromol/L) was 0.06+/-0.01 for control, 0.17+/-0.02 for rtPA, 0.22+/-0.07 for ISC, and 0.16+/-0. 04 for ISC-rtPA (P<0.05). CONCLUSIONS: These results demonstrate that both ischemia and rtPA perfusion diminish cerebral artery reactivity and that the combination may produce an additive effect. This impaired reactivity may contribute to reperfusion-induced injury during or after thrombolysis by altering upstream cerebrovascular resistance.

Acetylcholine↗

PubMed2000

Cervene (Nalmefene) in acute ischemic stroke : final results of a phase III efficacy study. The Cervene Stroke Study Investigators.

BACKGROUND AND PURPOSE: The goals of the present study were to assess the efficacy and safety of nalmefene (Cervene) in patients with acute (< or =6 hours) ischemic stroke and to investigate the safety of combined recombinant tissue plasminogen activator and nalmefene in a separate subset of patients. Nalmefene, an opioid antagonist with relative kappa receptor selectivity, has shown neuroprotective effects in multiple experimental central nervous system injury and ischemic models. Results from an earlier phase II study in patients with acute ischemic stroke suggested that nalmefene was safe and tolerable and may be effective for patients <70 years old. METHODS: This investigation was a phase III, placebo-controlled, double-blind, randomized study of a 24-hour infusion of nalmefene. Patients with acute ischemic stroke who had an onset of symptoms within 6 hours and a baseline score of > or =4 on the NIH Stroke Scale were randomized to receive either 60 mg nalmefene administered as a 10-mg bolus over 15 minutes and then a 50-mg infusion over 23.75 hours or placebo. The primary efficacy outcome was the proportion of patients achieving a score of > or =60 on the Barthel Index and a rating of "moderate disability" or better on the Glasgow Outcome Scale at 12 weeks. Assessments were performed at baseline (predose), hours 12 and 24, days 2 and 7, and week 12. RESULTS: A total of 368 patients were randomized at 42 centers, including 32 patients treated with recombinant tissue plasminogen activator and study drug. Nalmefene was well tolerated. Overall, there was no significant difference in 3-month functional outcome for nalmefene treatment compared with placebo on any of the planned analyses. A prospective secondary analysis also failed to find a treatment effect in patients <70 years old. CONCLUSIONS: Although nalmefene appears to be safe and well tolerated, this study failed to find any treatment benefit in stroke patients treated within 6 hours.

Acute Disease↗

PubMed2000

Lack of interleukin-6 expression is not protective against focal central nervous system ischemia.

BACKGROUND AND PURPOSE: Interleukin-6 (IL-6) appears to be involved in the inflammatory response associated with central nervous system (CNS) ischemia. Although IL-6 levels increase after stroke, it is not known whether IL-6 directly influences CNS ischemic injury. In this study, we used a focal reversible stroke model to investigate whether mice lacking IL-6 were protected against acute ischemic injury. METHODS: We bred IL-6-deficient C57 black mice (I-129 IL-6 KO back-crossed with C57), including homozygous knockouts (IL-6 -/-), heterozygous littermates (IL-6 +/-), and normal littermates (IL-6 +/+). The status of all animals was confirmed by DNA sampling and polymerase chain reaction analysis. Reversible middle cerebral artery occlusion was produced by advancing a silicone-coated 8-0 filament into the internal carotid artery for 2 hours (experiment 1) or 45 minutes (experiment 2). At 24 hours, animals were evaluated on a 28-point clinical scale, blood and cerebrospinal fluid were obtained, and the brains were evaluated for infarct volume and IL-6 mRNA levels. RESULTS: In experiment 1 (severe ischemia), no differences were seen in lesion size or neurological function between the groups: lesion volume was IL-6 -/- (n=15), 57+/-13 mm(3); IL-6 +/- (n=15), 58+/-23 mm(3); and IL-6 +/+ (n=15), 58+/-18 mm(3) (P=NS). ELISA testing confirmed very low to absent levels of IL-6 in the serum and cerebrospinal fluid of knockout animals. Brain mRNA levels of the other proinflammatory cytokines, including tumor necrosis factor-alpha, IL-1beta, and IL-1 receptor antagonist, were 50% lower in IL-6-deficient ischemic animals than in normal animals. In experiment 2 (mild ischemia), no differences were seen in lesion size or neurological function between the groups: lesion volume was IL-6 -/- (n=10), 16+/-8 mm(3); IL-6 +/- (n=10), 14+/-4 mm(3); and IL-6 +/+ (n=10), 19+/-12 mm(3) (P=NS). CONCLUSIONS: In this study, infarct size and neurological function at 24 hours were not different in animals deficient in IL-6 after transient CNS ischemia. This suggests that IL-6 does not have a direct influence on acute ischemic injury. Further study investigating the role of IL-6 on long-term recovery after stroke is in progress.

Acute Disease↗

PubMed1999

A highly enantioselective conjugate reduction of 3-arylinden-1-ones using bakers' yeast for the preparation of (S)-3-arylindan-1-ones.

[formula: see text] The bakers' yeast reduction of 3-(1,3-benzodioxol-5-yl)-6-propoxy-1H-inden-1-one 4 has been shown to give (S)-3-(1,3-benzodioxol-5-yl)-2,3-dihydro-6-propoxy-1H-indan-1-one 6 in 65% yield with high enantioselectivity (> 99.0% ee), a key intermediate for the synthesis of the endothelin receptor antagonist SB 217242. In addition, the substituted 3-arylinden-1-ones 10a-e gave equally high enantioselectivity for the 3-arylindan-1-one products 13a-e. Mechanistic studies of the reaction indicate the operative pathway to be an asymmetric conjugate reduction, wherein the hydride transfer from NAD(P)H occurs from the Re-face of the indenone substrate.

Carboxylic Acids↗

PubMed1999

Intra-arterial prourokinase for acute ischemic stroke. The PROACT II study: a randomized controlled trial. Prolyse in Acute Cerebral Thromboembolism.

CONTEXT: Intravenous tissue-type plasminogen activator can be beneficial to some patients when given within 3 hours of stroke onset, but many patients present later after stroke onset and alternative treatments are needed. OBJECTIVE: To determine the clinical efficacy and safety of intra-arterial (IA) recombinant prourokinase (r-proUK) in patients with acute stroke of less than 6 hours' duration caused by middle cerebral artery (MCA) occlusion. DESIGN: PROACT II (Prolyse in Acute Cerebral Thromboembolism II), a randomized, controlled, multicenter, open-label clinical trial with blinded follow-up conducted between February 1996 and August 1998. SETTING: Fifty-four centers in the United States and Canada. PATIENTS: A total of 180 patients with acute ischemic stroke of less than 6 hours' duration caused by angiographically proven occlusion of the MCA and without hemorrhage or major early infarction signs on computed tomographic scan. INTERVENTION: Patients were randomized to receive 9 mg of IA r-proUK plus heparin (n = 121) or heparin only (n = 59). MAIN OUTCOME MEASURES: The primary outcome, analyzed by intention-to-treat, was based on the proportion of patients with slight or no neurological disability at 90 days as defined by a modified Rankin score of 2 or less. Secondary outcomes included MCA recanalization, the frequency of intracranial hemorrhage with neurological deterioration, and mortality. RESULTS: For the primary analysis, 40% of r-proUK patients and 25% of control patients had a modified Rankin score of 2 or less (P = .04). Mortality was 25% for the r-proUK group and 27% for the control group. The recanalization rate was 66% for the r-proUK group and 18% for the control group (P<.001). Intracranial hemorrhage with neurological deterioration within 24 hours occurred in 10% of r-proUK patients and 2% of control patients (P = .06). CONCLUSION: Despite an increased frequency of early symptomatic intracranial hemorrhage, treatment with IA r-proUK within 6 hours of the onset of acute ischemic stroke caused by MCA occlusion significantly improved clinical outcome at 90 days.

Aged↗

PubMed1999

Recombinant tissue-type plasminogen activator (Alteplase) for ischemic stroke 3 to 5 hours after symptom onset. The ATLANTIS Study: a randomized controlled trial. Alteplase Thrombolysis for Acute Noninterventional Therapy in Ischemic Stroke.

CONTEXT: Recombinant tissue-type plasminogen activator (rt-PA) improves outcomes for patients with acute ischemic stroke, but current approved use is limited to within 3 hours of symptom onset. This restricts the number of patients who can be treated, since most stroke patients present more than 3 hours after symptom onset. OBJECTIVE: To test the efficacy and safety of rt-PA in patients with acute ischemic stroke when administered between 3 and 5 hours after symptom onset. DESIGN: The Alteplase ThromboLysis for Acute Noninterventional Therapy in Ischemic Stroke (ATLANTIS) study is a phase 3, placebo-controlled, double-blind randomized study conducted between December 1993 and July 1998, with up to 90 days of follow-up. SETTING: One hundred forty university and community hospitals in North America. PATIENTS: An intent-to-treat population of 613 acute ischemic stroke patients was enrolled, with 547 of these treated as assigned within 3 to 5 hours of symptom onset. A total of 39 others were treated within 3 hours of symptom onset, 24 were treated more than 5 hours after symptom onset, and 3 never received any study drug. INTERVENTION: Administration of 0.9 mg/kg of rt-PA (n = 272) or placebo (n = 275) intravenously over 1 hour. MAIN OUTCOME MEASURES: Primary efficacy was an excellent neurologic recovery at day 90 (National Institutes of Health Stroke Scale [NIHSS] score of < or =1); secondary end points included excellent recovery on functional outcome measures (Barthel index, modified Rankin scale, and Glasgow Outcome Scale) at days 30 and 90. Serious adverse events were also assessed. RESULTS: In the target population, 32% of the placebo and 34% of rt-PA patients had an excellent recovery at 90 days (P = .65). There were no differences on any of the secondary functional outcome measures. In the first 10 days treatment with rt-PA significantly increased the rate of symptomatic intracerebral hemorrhage (ICH) (1.1% vs 7.0% [P<.001]), a symptomatic ICH (4.7% vs 11.4% [P = .004]), and fatal ICH (0.3% vs 3.0% [P<.001]). Mortality at 90 days was 6.9% with placebo and 11.0% with rt-PA (P = .09). Results in the intent-to-treat population were similar. CONCLUSIONS: This study found no significant rt-PA benefit on the 90-day efficacy end points in patients treated between 3 and 5 hours. The risk of symptomatic ICH increased with rt-PA treatment. These results do not support the use of intravenous rt-PA for stroke treatment beyond 3 hours.

Aged↗

PubMed1999

Temporal modulation of cytokine expression following focal cerebral ischemia in mice.

There is increasing evidence that the inflammatory response plays an important role in CNS ischemia. The murine model of focal ischemia, however, remains incompletely characterized. In this study we examined expression of several cytokines and the vascular adhesion molecule E-selectin, in order to characterize the molecular events following stroke in the C57BL/6J mouse. Using a multi-probe RNAse protection assay (RPA), mRNA for 19 cytokines was analyzed following permanent and transient occlusion of the middle cerebral artery in mice. In addition, samples from the same mice were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) to evaluate E-selectin mRNA expression levels. Several cytokine mRNAs showed a similar expression pattern in both permanent and transient CNS ischemia while others showed a temporal expression pattern that was dependent on the type of stroke. For both models, mRNA levels of TNFalpha rose early (4 h) followed by IL-6 (10-18 h) and a comparatively late increase (96 h) in TGFbeta1. IL-1alpha, IL-1beta and IL-1ra levels showed a model dependent shift in temporal expression. Reperfusion appeared to delay the induction of these cytokines. Temporal changes in cytokine mRNA expression in the mouse CNS occur following ischemic damage. Our findings demonstrate the utility and power of multi-probe RPA for evaluation of changes in cytokine mRNA levels. Moreover, this study is, to our knowledge the first to show temporal changes in cytokine mRNA in mouse cerebral ischemia, forming a basis for further exploration of the roles of these cytokines in modulating ischemic neuronal damage in this model.

Animals↗

PubMed1999

Microalbuminuria in ischemic stroke.

OBJECTIVES: To determine (1) the incidence of microalbuminuria in patients with recent ischemic stroke, (2) its relationship to risk factors for stroke, (3) its prevalence in the major subtypes of ischemic stroke, and (4) its potential for identifying patients at increased risk for recurrent stroke, myocardial infarction, or vascular death. DESIGN: Prospective case-control study. SETTING: Outpatient clinics at the medical centers affiliated with the Department of Veterans Affairs and Oregon Health Sciences University in Portland, Ore. PATIENTS: A total of 186 older men and women (median age, 65 years) who were enrolled in a prospective study of risk factors for recurrent stroke, including 97 patients with recent (6-8 weeks) ischemic stroke, 51 with similar clinical risk factors for stroke, including 24 with a history of remote stroke or transient ischemic attack, and 38 community-dwelling volunteers. RESULTS: Microalbuminuria was 3 times more prevalent in patients with recent stroke (29%) than in those with clinical risk factors for stroke (10%), and was undetectable in healthy elderly controls (P<.001). The presence of microalbuminuria in recent stroke as well as in the combined recent and remote stroke or transient ischemic attack group (n = 121) was predicted by diabetes (odds ratio [OR], 8.4; 95% confidence interval [CI], 2.6-27.0; P<.001; serum albumin levels (OR, 0.12; 95% CI, 0.03-0.50; P<.005); age (OR, 1.1; 95% CI, 1.0-1.2; P<.01), and ischemic heart disease (OR, 3.0; 95% CI, 1.0-9.1; P<.05). Among patients with recent stroke the prevalence of microalbuminuria did not differ among major ischemic stroke subtypes, ie, atheroembolic, 23%; cardioembolic, 30%; and lacunar, 33%. During a mean +/- SD of 1.5 +/- 0.9 years of follow-up, 20% of patients with recent stroke, 14% with risk factors for stroke, and 0% of healthy elderly volunteers had vascular end points (P<.004), with events being as frequent in patients with microalbuminuria (32%) as in patients with macroalbuminuria (33%). After controlling for major clinical risk factors, microalbuminuria remained an independently significant predictor of future stroke in the combined recent stroke and remote stroke or transient ischemic attack group (Cox proportional hazard ratio, 4.9; 95% CI, 1.4-17.6; P<.01). CONCLUSIONS: Microalbuminuria is a common finding in patients with cerebrovascular disease and is associated with increased risk for stroke even after correction for the presence of confounding clinical risk factors. These data suggest that microalbuminuria merits further examination as a potentially inexpensive and easily measured marker of increased risk for stroke.

Aged↗

PubMed1999

Time course of IL-6 expression in experimental CNS ischemia.

Interleukin-6 (IL-6) appears to be an important modulator of the inflammatory response associated with CNS ischemia. Clinically, IL-6 values obtained in the first week post-stroke have been shown to correlate with infarct size and outcome. In this study we used a focal reversible stroke model to investigate the time course and relationship to outcome of IL-6 production in plasma, brain and CSF. Reversible middle cerebral artery occlusion or sham surgery was produced in 50 adult Swiss Webster mice by advancing an 8-0 filament into the internal carotid artery for 2 h (sham 1 min). At 3, 6, 12, 24, and 72 h (8 each ischemia; 2 each sham) groups of animals were evaluated on a 28 point clinical scale, blood and CSF obtained, and the brains were evaluated for infarct volume and IL-6 mRNA levels. Serum levels of IL-6 (ELISA mean +/- SD; undetectable in controls) overall sham group, 102 +/- 87; 3 h, 908 +/- 494* pg ml-1; 6 h, 1079 +/- 468* pg ml-1; 12 h, 980 +/- 221* pg ml-1; pg ml-1; 24 h, 320 +/- 314* pg ml-1; 72 h, 20 +/- 30* pg ml-1 (*p < or = 0.05 to sham). CSF levels (ELISA) overall sham group, 10 +/- 18; 3 h, 379 +/- 210* pg ml-1; 6 h, 157 +/- 61* pg ml-1; 12 h, 136 +/- 88* pg ml-1; 24 h, 127 +/- 99 pg ml-1; 72 h, 72 +/- 9* pg ml-1 (*p < or = 0.05 to sham). Brain IL-6 mRNA levels overall sham group, 20; 3 h, 480; 6 h, 599; 12 h, 7960; 24 h, 20267; 72 h, 0. There was an overall R2 of 0.20 between plasma and CSF IL-6. There was an overall R2 of 0.13 and 0.20 between infarct size and serum and CSF IL-6 level respectively, and an overall R2 of 0.10 and 0.17 between neurologic function and serum and CSF IL-6 level respectively. These findings confirm that IL-6 values increase following CNS ischemia with peak serum and CSF levels occurring before brain values. CSF IL-6 levels had a stronger correlation with neurologic function and infarct size than serum.

Age Factors↗

PubMed1999

A randomized efficacy trial of citicoline in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: Citicoline (cytidine-5'-diphosphocholine; CDP-choline) may reduce central nervous system ischemic injury by stabilizing cell membranes and reducing free radical generation. A previous dose-comparison trial in patients with acute stroke found that 500 mg of citicoline appeared to improve neurological outcome with minimal side effects. METHODS: The current trial was a 33-center, randomized, double-blind, efficacy trial in 394 patients comparing placebo (n=127) with citicoline (n=267) (500 mg po daily) for 6 weeks, with a 6-week posttreatment follow-up period. Patients with acute (24 hours) ischemic strokes clinically assessed to be in the middle cerebral artery territory with National Institutes of Health Stroke Scale (NIHSS) > or = 5 were enrolled. RESULTS: Mean time to treatment was 12 hours, and mean age was 71 for placebo and 70 for citicoline. Although mean baseline NIHSS were similar for both groups, there was a higher percentage of placebo patients with NIHSS <8 (34% vs 22%; P<0.01). The incidence and type of side effects were similar between the groups. The planned primary analysis (logistic regression: 5 categories Barthel) failed the proportional odds assumption and was rendered unreliable. There were no between-group differences seen on the planned secondary assessment analyses at 90 days, including the Barthel Index > or = 95 at 12 weeks (last observation carried forward: placebo 40%; citicoline 40%) or mortality rate (placebo 18%; citicoline 17%). However, post hoc analyses in a subgroup of patients with baseline NIHSS > or = 8 found that citicoline-treated patients were more likely to have a full recovery (Barthel > or = 95): placebo 21%; citicoline 33%; P=0.05; whereas no difference was seen in patients with baseline NIHSS<8 (placebo 77%; citicoline 69%; P>0.1. CONCLUSIONS: The results of this study indicate that citicoline was safe but ineffective in improving the outcome of patients with acute ischemic stroke who were enrolled in this trial. Post hoc analyses indicate that there may be a subgroup of patients with moderate to severe strokes who would benefit.

Aged↗

PubMed1999

Dose escalation study of the NMDA glycine-site antagonist licostinel in acute ischemic stroke.

BACKGROUND AND PURPOSE: Licostinel (ACEA 1021; 5-nitro-6, 7-dichloro-2,3-quinoxalinedione), a competitive antagonist of glycine at the N-methyl-D-aspartate (NMDA) receptor, is an effective neuroprotective agent in animal models of cerebral ischemia. The purpose of this study was to assess the safety, tolerability, and pharmacokinetics of licostinel in patients with acute stroke. METHODS: In this 5-center dose escalation trial, patients were enrolled within 48 hours of an ischemic stroke and treated with ascending doses of a short infusion of licostinel or a placebo. Adverse effects were assessed with clinical and laboratory measurements, and patient outcome was determined with the National Institutes of Health Stroke Scale. RESULTS: Sixty-four patients (44 treated with escalating doses of licostinel and 20 who received placebo) were treated. Lower doses of licostinel (0.03 to 0.60 mg/kg) were not associated with any significant adverse effects. Higher doses of licostinel (1.2 to 3.0 mg/kg) were associated with a variety of mild-to-moderate adverse effects including neurological and gastrointestinal complaints. No major psychotomimetic effects or significant safety concerns occurred. At the higher dose levels, peak plasma concentrations of licostinel were substantially higher than those required for neuroprotection in animal stroke models. A similar improvement in National Institutes of Health Stroke Scale scores over time was seen in both the placebo group and the licostinel-treated patients. CONCLUSIONS: A short infusion of licostinel in doses up to 3.0 mg/kg is safe and tolerable in acute stroke patients. Licostinel may be a safer and better tolerated neuroprotective agent than many of the previously evaluated NMDA antagonists.

Acute Disease↗