human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background and Purpose — Among patients with acute stroke , high blood pressure is often associated with poor outcome , although the reason is unclear . We analyzed data from the International Stroke Trial ( IST ) to explore the relationship between  systolic blood pressure ( SBP ) , subsequent clinical events over the next 2 weeks , and functional outcome at 6 months in patients with acute stroke . Methods — We included in the analysis 17 398 patients from IST with confirmed ischemic stroke . A single measurement of SBP was made immediately before r and omization . Clinical events within 14 days of r and omization were recorded : recurrent ischemic stroke , symptomatic intracranial hemorrhage , death result ing from presumed cerebral edema , fatal coronary heart disease , and death . Survival and dependency were assessed at 6 months . Outcomes were adjusted for age , sex , clinical stroke syndrome , time to r and omization , consciousness level , atrial fibrillation , and treatment allocation ( aspirin , unfractionated heparin , both , or neither ) . Results — A U-shaped relationship was found between baseline SBP and both early death and late death or dependency : early death increased by 17.9 % for every 10 mm Hg below 150 mm Hg ( P < 0.0001 ) and by 3.8 % for every 10 mm Hg above 150 mm Hg ( P = 0.016 ) . The rate of recurrent ischemic stroke within 14 days increased by 4.2 % for every 10–mm Hg increase in SBP ( P = 0.023 ) ; this association was present in both fatal and nonfatal recurrence . Death result ing from presumed cerebral edema was independently associated with high SBP ( P = 0.004 ) . No relationship between symptomatic intracranial hemorrhage and SBP was seen . Low SBP was associated with a severe clinical stroke ( total anterior circulation syndrome ) and an excess of deaths from coronary heart disease ( P = 0.002 ) . Conclusions — Both high blood pressure and low blood pressure were independent prognostic factors for poor outcome , relationships that appear to be mediated in part by increased rates of early recurrence and death result ing from presumed cerebral edema in patients with high blood pressure and increased coronary heart disease events in those with low blood pressure . The occurrence of symptomatic intracranial hemorrhage within 14 days was independent of SBP Background and Purpose — Hemiparesis is the commonest disabling deficit caused by stroke . In animals , dextroamphetamine ( AMPH ) paired with training enhances motor recovery , but its clinical efficacy is uncertain . Methods — In a r and omized , double-blind , placebo-controlled trial , 71 stroke patients were stratified by hemiparesis severity and r and omly assigned to 10 sessions of physiotherapy coupled with either 10 mg AMPH or placebo . Study treatments were administered by 1 physiotherapist , beginning 5 to 10 days after stroke and continuing twice per week for 5 weeks . Outcomes were assessed by 1 physiotherapist at baseline , after each treatment session , at 6 weeks , and at 3 months . The primary outcome was motor recovery ( impairment level ) on the Fugl-Meyer ( FM ) scale . Secondary outcomes assessed mobility , ambulation , arm/h and function , and independence in activities of daily living . Results — Baseline hemiparesis was severe overall ( mean FM score 27.7±20.0 ) . Motor scores improved during treatment in both groups ( mean change , baseline to 3 months 29.5±16.6 ) . Repeated- measures ANOVA revealed no significant differences in recovery between the treatment groups for the entire cohort ( n=67 ) or for subgroups with a severe hemiparesis ( n=43 ) , moderate hemiparesis ( n=24 ) , or cortically based stroke ( n=26 ) . In the moderate subgroup , there was a significant drug × time interaction for upper extremity motor recovery ( F=5.14 ; P<0.001 ) , although there was a significant baseline imbalance in motor scores in this subgroup . Conclusion — In stroke patients with a severe motor deficit , 10 mg AMPH coupled with physiotherapy twice per week for 5 weeks in the early poststroke period provided no additional benefit in motor or functional recovery compared with physiotherapy alone . Patients with moderate severity hemiparesis deserve further investigation . Increased intensity and longer duration drug/therapy dosing regimens should be explored , targeting the upper and lower limbs separately Despite advances in acute treatment of ischemic cerebrovascular events , the most common clinical outcome is disabling neurological impairment . Despite experimental evidence that psychostimulant treatment can positively affect recovery rate after focal brain lesions , beyond rehabilitation therapies there are no currently accepted medical treatments indicated for diminishing neurological impairment after clinical ly established stroke . To test the effect of amphetamine , task-specific training , limiting motor experience , and their interaction on motor recovery in a postacute animal model of stroke , animals were nonaversively trained in beam walking before a unilateral photochemical sensorimotor cortex lesion and tested for 10 days after lesion . Animals were r and omized to groups receiving : a single session of motor training 24 h after lesion ; a single injection of amphetamine 2 mg/kg 24 h after lesion ; beam-walking experience limited to testing on days 1 and 10 after lesion ; and groups that received amphetamine treatment combined with training or combined with limited experience .  Motor recovery was maximally enhanced by training , delayed by amphetamine treatment , and most negatively affected by limiting beam-walking experience during the recovery period . These findings support physical training after stroke , indicating that limiting physical activity negatively affects motor recovery and raises questions about the role of stimulant treatment to enhance motor recovery in the postacute phase after stroke Functional magnetic resonance imaging was used to evaluate the effects of oral d-amphetamine on brain activation elicited by auditory and simple motor tasks in ten normal right-h and ed subjects . We measured the percent signal change and number of voxels activated by a tone discrimination task and a right h and finger-tapping task after 20 mg of d-amphetamine and after placebo . Compared to placebo , amphetamine significantly increased the number of activated voxels in the left and right primary auditory cortices during the tone discrimination task and increased the number of activated voxels in the ipsilateral primary sensorimotor cortex and right middle frontal area during the motor task . Although highly specific vascular effects of drug can not be ruled out as an explanation , these results could also mean that amphetamine increases the neuronal activity associated with each of these two tasks Background and Purpose — The baroreceptor reflex arc is important in the short-term regulation of the cardiovascular system , and small studies have reported impaired cardiac baroreceptor sensitivity ( BRS ) after acute stroke . However , the prognostic significance of impaired BRS is uncertain . Methods — One hundred twenty-four patients underwent simultaneous ECG and noninvasive beat-to-beat blood pressure ( BP ) monitoring within 72 hours of neuroradiologically confirmed acute ischemic stroke . Cardiac BRS was assessed from the combined & agr;-index by means of power spectral analysis techniques . Baseline data for acute stroke patients were compared with those of a control group matched for age , sex , and casual BP . Patients were followed up for a median of 1508 days ( range , 9 to 2656 days ) , and outcome was compared between patients with and without impaired BRS . Results — Median BRS values were significantly lower in stroke patients than in controls ( 5 [ interquartile range , 3.5 to 7.4 ] versus 6.2 [ interquartile range , 4.5 to 8.3 ] ms/mm Hg;P = 0.04 ) . Sixty-one ( 33 male ) patients ( mean age , 70.2 [ SD 10.5 ] years ) had impaired BRS ( ≤5.0 ms/mm Hg ) compared with 63 ( 35 male ) patients ( mean age , 70.6 [ SD 11.7 ] years ) without impaired BRS ( > 5.0 ms/mm Hg ) . Stroke patients with impaired BRS values had a significantly poorer prognosis ( 28 % versus 8 % mortality rate during the follow-up period ) although there were no differences in age , stroke severity , stroke type , or casual or 24-hour BP parameters between the 2 groups . Conclusions — Impaired cardiac BRS is associated with increased long-term mortality after acute ischemic stroke , irrespective of age , sex , stroke type , and BP . This may reflect cardiac arrhythmias , but the mechanisms underlying this association are unknown , although therapies that improve cardiac BRS after stroke warrant further investigation PURPOSE To assess the effects of d-amphetamine on motor facilitation and recovery in stroke patients with mild arm paresis receiving the Arm Ability training . METHODS Thirty-one stroke patients with mild arm paresis were r and omly assigned to either ( a. ) receiving placebo or ( b. ) d-amphetamine twice a week 2 hours before Arm Ability training sessions for three weeks . MAIN OUTCOME MEASURE time needed to perform TEMPA tasks , a measure of upper extremity performance reflecting everyday life tasks . Secondary measures : aim ed movements , tapping , and a 10 m walkway as well as motor performance during training sessions . RESULTS The interim efficacy analysis of 26 stroke patients who completed the study intervention showed overall arm motor recovery both from pre to post test after 3 weeks of training and from pre test to follow-up 1 year later . No superior effect of d-amphetamine over placebo could be substantiated for either motor facilitation during training or motor recovery ( post training or long-term ) . D-amphetamine exerted mild effects on blood pressure . Serious adverse events were not observed . CONCLUSIONS d-Amphetamine failed to facilitate motor performance during training sessions , to promote skill acquisition with training tasks , and most importantly to enhance motor recovery among patients with mild arm paresis after stroke Background and Purpose — Amphetamine is reported to enhance recovery after experimental stroke , but results from the first few trials in humans are inconclusive . Limited information is available on treatment safety . This study intended to investigate the safety and tolerability of dexamphetamine in patients with acute cerebral ischemia . Methods — Forty-five patients with cerebral ischemia were enrolled within 72 hours after onset of symptoms . Patients were r and omized to 1 of 3 dose levels ( 2.5 , 5 , or 10 mg orally twice daily ) or placebo for 5 consecutive days . Adverse events , blood pressure , heart rate , body temperature , consciousness level , and functional outcome measures were followed up daily during treatment . Follow-ups were made at day 7 and 1 and 3 months after stroke . Results — Mean systolic and diastolic blood pressures and heart rate increased 14 mm Hg , 8 mm Hg , and 9 bpm , respectively , with dexamphetamine treatment compared with placebo ( P ≤0.01 ) . There was no difference between dexamphetamine and placebo  regarding adverse events , body temperature , or consciousness level . During treatment , there was a benefit of dexamphetamine in neurological and functional outcome ( P < 0.05 ) , but differences were not maintained at follow-up . Conclusions — Overall , dexamphetamine was safe and well tolerated by patients with acute cerebral ischemia , but blood pressure and heart rate increased during treatment in comparison to placebo . These observations may be important in the future planning of amphetamine trials because changes in these variables have been observed to interfere with clinical outcome . The suggestions of improvement in outcome must be confirmed in further studies Practice -dependent plasticity underlies motor learning in everyday life and motor relearning after lesions of the nervous system . Previous studies showed that practice -dependent plasticity is modifiable by neuromodulating transmitters such as norepinephrine ( NE ) , dopamine ( DA ) or acetylcholine ( ACh ) . Here we explored , for the first time comprehensively and systematic ally , the modifying effects of an agonist versus antagonist in each of these neuromodulating transmitter systems on practice -dependent plasticity in healthy subjects in a  placebo-controlled , r and omized , double-blind crossover design . We found that the agonists in all three neuromodulating transmitter systems ( NE : methylpheni date ; DA : cabergoline ; ACh : tacrine ) enhanced practice -dependent plasticity , whereas the antagonists decreased it ( NE : prazosin ; DA : haloperidol ; ACh : biperiden ) . Enhancement of plasticity under methylpheni date and tacrine was associated with an increase in corticomotoneuronal excitability of the prime mover of the practice , as measured by the motor evoked potential amplitude , but with a decrease under cabergoline . Our findings demonstrate that agonists and antagonists in various neuromodulating transmitter systems produce significant and oppositely directed modifications of practice -dependent plasticity in human motor cortex . Enhancement of plasticity occurred through different strategies that either favoured extrinsic ( NE , ACh ) or intrinsic ( DA ) modulating influence on the motor cortical output network Amphetamine enhances recovery after experimental ischaemia and has shown promise in small clinical trials when combined with motor or sensory stimulation . Amphetamine , a sympathomimetic , might have haemodynamic effects in stroke patients , although limited data have been published . Subjects were recruited 3–30 days post-ischaemic stroke into a phase II r and omized ( 1:1 ) , double-blind , placebo-controlled trial . Subjects received dexamphetamine ( 5 mg initially , then 10 mg for 10 subsequent doses with 3- or 4-day 
    Output:
    
agent
No evidence exists at present to support the use of amphetamine after stroke .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background and Purpose — Among patients with acute stroke , high blood pressure is often associated with poor outcome , although the reason is unclear . We analyzed data from the International Stroke Trial ( IST ) to explore the relationship between  systolic blood pressure ( SBP ) , subsequent clinical events over the next 2 weeks , and functional outcome at 6 months in patients with acute stroke . Methods — We included in the analysis 17 398 patients from IST with confirmed ischemic stroke . A single measurement of SBP was made immediately before r and omization . Clinical events within 14 days of r and omization were recorded : recurrent ischemic stroke , symptomatic intracranial hemorrhage , death result ing from presumed cerebral edema , fatal coronary heart disease , and death . Survival and dependency were assessed at 6 months . Outcomes were adjusted for age , sex , clinical stroke syndrome , time to r and omization , consciousness level , atrial fibrillation , and treatment allocation ( aspirin , unfractionated heparin , both , or neither ) . Results — A U-shaped relationship was found between baseline SBP and both early death and late death or dependency : early death increased by 17.9 % for every 10 mm Hg below 150 mm Hg ( P < 0.0001 ) and by 3.8 % for every 10 mm Hg above 150 mm Hg ( P = 0.016 ) . The rate of recurrent ischemic stroke within 14 days increased by 4.2 % for every 10–mm Hg increase in SBP ( P = 0.023 ) ; this association was present in both fatal and nonfatal recurrence . Death result ing from presumed cerebral edema was independently associated with high SBP ( P = 0.004 ) . No relationship between symptomatic intracranial hemorrhage and SBP was seen . Low SBP was associated with a severe clinical stroke ( total anterior circulation syndrome ) and an excess of deaths from coronary heart disease ( P = 0.002 ) . Conclusions — Both high blood pressure and low blood pressure were independent prognostic factors for poor outcome , relationships that appear to be mediated in part by increased rates of early recurrence and death result ing from presumed cerebral edema in patients with high blood pressure and increased coronary heart disease events in those with low blood pressure . The occurrence of symptomatic intracranial hemorrhage within 14 days was independent of SBP Background and Purpose — Hemiparesis is the commonest disabling deficit caused by stroke . In animals , dextroamphetamine ( AMPH ) paired with training enhances motor recovery , but its clinical efficacy is uncertain . Methods — In a r and omized , double-blind , placebo-controlled trial , 71 stroke patients were stratified by hemiparesis severity and r and omly assigned to 10 sessions of physiotherapy coupled with either 10 mg AMPH or placebo . Study treatments were administered by 1 physiotherapist , beginning 5 to 10 days after stroke and continuing twice per week for 5 weeks . Outcomes were assessed by 1 physiotherapist at baseline , after each treatment session , at 6 weeks , and at 3 months . The primary outcome was motor recovery ( impairment level ) on the Fugl-Meyer ( FM ) scale . Secondary outcomes assessed mobility , ambulation , arm/h and function , and independence in activities of daily living . Results — Baseline hemiparesis was severe overall ( mean FM score 27.7±20.0 ) . Motor scores improved during treatment in both groups ( mean change , baseline to 3 months 29.5±16.6 ) . Repeated- measures ANOVA revealed no significant differences in recovery between the treatment groups for the entire cohort ( n=67 ) or for subgroups with a severe hemiparesis ( n=43 ) , moderate hemiparesis ( n=24 ) , or cortically based stroke ( n=26 ) . In the moderate subgroup , there was a significant drug × time interaction for upper extremity motor recovery ( F=5.14 ; P<0.001 ) , although there was a significant baseline imbalance in motor scores in this subgroup . Conclusion — In stroke patients with a severe motor deficit , 10 mg AMPH coupled with physiotherapy twice per week for 5 weeks in the early poststroke period provided no additional benefit in motor or functional recovery compared with physiotherapy alone . Patients with moderate severity hemiparesis deserve further investigation . Increased intensity and longer duration drug/therapy dosing regimens should be explored , targeting the upper and lower limbs separately Despite advances in acute treatment of ischemic cerebrovascular events , the most common clinical outcome is disabling neurological impairment . Despite experimental evidence that psychostimulant treatment can positively affect recovery rate after focal brain lesions , beyond rehabilitation therapies there are no currently accepted medical treatments indicated for diminishing neurological impairment after clinical ly established stroke . To test the effect of amphetamine , task-specific training , limiting motor experience , and their interaction on motor recovery in a postacute animal model of stroke , animals were nonaversively trained in beam walking before a unilateral photochemical sensorimotor cortex lesion and tested for 10 days after lesion . Animals were r and omized to groups receiving : a single session of motor training 24 h after lesion ; a single injection of amphetamine 2 mg/kg 24 h after lesion ; beam-walking experience limited to testing on days 1 and 10 after lesion ; and groups that received amphetamine treatment combined with training or combined with limited experience .  Motor recovery was maximally enhanced by training , delayed by amphetamine treatment , and most negatively affected by limiting beam-walking experience during the recovery period . These findings support physical training after stroke , indicating that limiting physical activity negatively affects motor recovery and raises questions about the role of stimulant treatment to enhance motor recovery in the postacute phase after stroke Functional magnetic resonance imaging was used to evaluate the effects of oral d-amphetamine on brain activation elicited by auditory and simple motor tasks in ten normal right-h and ed subjects . We measured the percent signal change and number of voxels activated by a tone discrimination task and a right h and finger-tapping task after 20 mg of d-amphetamine and after placebo . Compared to placebo , amphetamine significantly increased the number of activated voxels in the left and right primary auditory cortices during the tone discrimination task and increased the number of activated voxels in the ipsilateral primary sensorimotor cortex and right middle frontal area during the motor task . Although highly specific vascular effects of drug can not be ruled out as an explanation , these results could also mean that amphetamine increases the neuronal activity associated with each of these two tasks Background and Purpose — The baroreceptor reflex arc is important in the short-term regulation of the cardiovascular system , and small studies have reported impaired cardiac baroreceptor sensitivity ( BRS ) after acute stroke . However , the prognostic significance of impaired BRS is uncertain . Methods — One hundred twenty-four patients underwent simultaneous ECG and noninvasive beat-to-beat blood pressure ( BP ) monitoring within 72 hours of neuroradiologically confirmed acute ischemic stroke . Cardiac BRS was assessed from the combined & agr;-index by means of power spectral analysis techniques . Baseline data for acute stroke patients were compared with those of a control group matched for age , sex , and casual BP . Patients were followed up for a median of 1508 days ( range , 9 to 2656 days ) , and outcome was compared between patients with and without impaired BRS . Results — Median BRS values were significantly lower in stroke patients than in controls ( 5 [ interquartile range , 3.5 to 7.4 ] versus 6.2 [ interquartile range , 4.5 to 8.3 ] ms/mm Hg;P = 0.04 ) . Sixty-one ( 33 male ) patients ( mean age , 70.2 [ SD 10.5 ] years ) had impaired BRS ( ≤5.0 ms/mm Hg ) compared with 63 ( 35 male ) patients ( mean age , 70.6 [ SD 11.7 ] years ) without impaired BRS ( > 5.0 ms/mm Hg ) . Stroke patients with impaired BRS values had a significantly poorer prognosis ( 28 % versus 8 % mortality rate during the follow-up period ) although there were no differences in age , stroke severity , stroke type , or casual or 24-hour BP parameters between the 2 groups . Conclusions — Impaired cardiac BRS is associated with increased long-term mortality after acute ischemic stroke , irrespective of age , sex , stroke type , and BP . This may reflect cardiac arrhythmias , but the mechanisms underlying this association are unknown , although therapies that improve cardiac BRS after stroke warrant further investigation PURPOSE To assess the effects of d-amphetamine on motor facilitation and recovery in stroke patients with mild arm paresis receiving the Arm Ability training . METHODS Thirty-one stroke patients with mild arm paresis were r and omly assigned to either ( a. ) receiving placebo or ( b. ) d-amphetamine twice a week 2 hours before Arm Ability training sessions for three weeks . MAIN OUTCOME MEASURE time needed to perform TEMPA tasks , a measure of upper extremity performance reflecting everyday life tasks . Secondary measures : aim ed movements , tapping , and a 10 m walkway as well as motor performance during training sessions . RESULTS The interim efficacy analysis of 26 stroke patients who completed the study intervention showed overall arm motor recovery both from pre to post test after 3 weeks of training and from pre test to follow-up 1 year later . No superior effect of d-amphetamine over placebo could be substantiated for either motor facilitation during training or motor recovery ( post training or long-term ) . D-amphetamine exerted mild effects on blood pressure . Serious adverse events were not observed . CONCLUSIONS d-Amphetamine failed to facilitate motor performance during training sessions , to promote skill acquisition with training tasks , and most importantly to enhance motor recovery among patients with mild arm paresis after stroke Background and Purpose — Amphetamine is reported to enhance recovery after experimental stroke , but results from the first few trials in humans are inconclusive . Limited information is available on treatment safety . This study intended to investigate the safety and tolerability of dexamphetamine in patients with acute cerebral ischemia . Methods — Forty-five patients with cerebral ischemia were enrolled within 72 hours after onset of symptoms . Patients were r and omized to 1 of 3 dose levels ( 2.5 , 5 , or 10 mg orally twice daily ) or placebo for 5 consecutive days . Adverse events , blood pressure , heart rate , body temperature , consciousness level , and functional outcome measures were followed up daily during treatment . Follow-ups were made at day 7 and 1 and 3 months after stroke . Results — Mean systolic and diastolic blood pressures and heart rate increased 14 mm Hg , 8 mm Hg , and 9 bpm , respectively , with dexamphetamine treatment compared with placebo ( P ≤0.01 ) . There was no difference between dexamphetamine and placebo  regarding adverse events , body temperature , or consciousness level . During treatment , there was a benefit of dexamphetamine in neurological and functional outcome ( P < 0.05 ) , but differences were not maintained at follow-up . Conclusions — Overall , dexamphetamine was safe and well tolerated by patients with acute cerebral ischemia , but blood pressure and heart rate increased during treatment in comparison to placebo . These observations may be important in the future planning of amphetamine trials because changes in these variables have been observed to interfere with clinical outcome . The suggestions of improvement in outcome must be confirmed in further studies Practice -dependent plasticity underlies motor learning in everyday life and motor relearning after lesions of the nervous system . Previous studies showed that practice -dependent plasticity is modifiable by neuromodulating transmitters such as norepinephrine ( NE ) , dopamine ( DA ) or acetylcholine ( ACh ) . Here we explored , for the first time comprehensively and systematic ally , the modifying effects of an agonist versus antagonist in each of these neuromodulating transmitter systems on practice -dependent plasticity in healthy subjects in a  placebo-controlled , r and omized , double-blind crossover design . We found that the agonists in all three neuromodulating transmitter systems ( NE : methylpheni date ; DA : cabergoline ; ACh : tacrine ) enhanced practice -dependent plasticity , whereas the antagonists decreased it ( NE : prazosin ; DA : haloperidol ; ACh : biperiden ) . Enhancement of plasticity under methylpheni date and tacrine was associated with an increase in corticomotoneuronal excitability of the prime mover of the practice , as measured by the motor evoked potential amplitude , but with a decrease under cabergoline . Our findings demonstrate that agonists and antagonists in various neuromodulating transmitter systems produce significant and oppositely directed modifications of practice -dependent plasticity in human motor cortex . Enhancement of plasticity occurred through different strategies that either favoured extrinsic ( NE , ACh ) or intrinsic ( DA ) modulating influence on the motor cortical output network Amphetamine enhances recovery after experimental ischaemia and has shown promise in small clinical trials when combined with motor or sensory stimulation . Amphetamine , a sympathomimetic , might have haemodynamic effects in stroke patients , although limited data have been published . Subjects were recruited 3–30 days post-ischaemic stroke into a phase II r and omized ( 1:1 ) , double-blind , placebo-controlled trial . Subjects received dexamphetamine ( 5 mg initially , then 10 mg for 10 subsequent doses with 3- or 4-day 
    Output:
    