***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: Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Abstract Objective .—To determine the efficacy of 2 different sources of Ginkgo biloba extract ( GBE ) in reducing the incidence and severity of acute mountain sickness ( AMS ) following rapid ascent to high altitude . Methods .—Two r and omized , double-blind , placebo-controlled cohort studies were conducted in which participants were treated with GBE ( 240 mg·d−1 ) or placebo prior to and including the day of ascent from 1600 m to 4300 m ( ascent in 2 hours by car ) . Acute mountain sickness was diagnosed if the Environmental Symptom Question naire III acute mountain sickness – cerebral ( AMS-C ) score was ≥0.7 and the Lake Louise Symptom ( LLS ) score was ≥3 and the participant reported a headache . Symptom severity was also determined by these scores . Results .— Results were conflicting : Ginkgo biloba  reduced the incidence and severity of AMS compared to placebo in the first but not the second study . In the first study , GBE reduced AMS incidence ( 7/21 ) vs placebo ( 13/19 ) ( P = .027 , number needed to treat = 3 ) , and it also reduced severity ( AMS-C = 0.77 ± 0.26 vs 1.59 ± 0.27 , P = .029 ) . In the second study , GBE did not reduce incidence or severity of AMS ( GBE 4/15 vs placebo 10/22 , P = .247 ; AMS-C = 0.48 ± 0.13 vs 0.58 ± 0.11 , P = .272 ) . The primary difference between the 2 studies was the source of GBE . Conclusions .—The source and composition of GBE products may determine the effectiveness of GBE for prophylaxis of AMS BACKGROUND Acute mountain sickness ( AMS ) commonly occurs when unacclimatized individuals ascend to altitudes above 2000 m.  Acetazolamide and Ginkgo biloba have both been recommended for AMS prophylaxis ; however , there is conflicting evidence regarding the efficacy of Ginkgo biloba use . We performed a r and omized , placebo-controlled trial of acetazolamide vs Ginkgo biloba for AMS prophylaxis . METHODS We r and omized unacclimatized adults to receive acetazolamide , Ginkgo biloba , or placebo in double-blind fashion and took them to an elevation of 3800 m for 24 hours . We grade d AMS symptoms using the Lake Louise Acute Mountain Sickness Scoring System ( LLS ) and compared the incidence of AMS ( defined as LLS score > or =3 and headache ) . RESULTS Fifty-seven subjects completed the trial ( 20 received acetazolamide ; 17 , Ginkgo biloba , and 20 , placebo ) . The LLS scores were significantly different between groups ; the median score of the acetazolamide group was significantly lower than that of the placebo group ( P=.01 ; effect size , 2 ; and 95 % confidence interval [ CI ] , 0 to 3 ) , unlike that of the Ginkgo biloba group ( P=.89 ; effect size , 0 ; and 95 % CI , -2 to 2 ) . Acute mountain sickness occurred less frequently in the acetazolamide group than in the placebo group ( effect size , 30 % ; 95 % CI , 61 % to -15 % ) , and the frequency of occurrence was similar between the Ginkgo biloba group and the placebo group ( effect size , -5 % ; 95 % CI , -37 % to 28 % ) . CONCLUSIONS In this study , prophylactic acetazolamide therapy decreased the symptoms of AMS and trended toward reducing its incidence . We found no evidence of similar efficacy for Ginkgo biloba BACKGROUND Acute mountain sickness ( AMS ) is a pathophysiological symptom complex that occurs in high-altitude areas . The incidence of AMS on Jade Mountain , the highest peak in Taiwan ( 3952 m ) , has been reported to be ∼36 % . There is a lack of data in children trekking at altitude in Taiwan . The purpose of this study was to determine the incidence , risk factors and symptoms of AMS in children trekking on Jade Mountain , Taiwan . METHODS This prospect i ve cohort study included a total of 96 healthy non-acclimatized children aged 11 - 12 years who trekked from an elevation of 2600 - 3952 m in 3 days .  The Lake Louise AMS score  was used to record symptoms associated with AMS . RESULTS AMS were reported in 59 % of children trekking on Jade Mountain over a 3 day period . AMS incidence increased significantly with increasing altitude . The most common AMS symptom was headache , followed by fatigue or weakness , difficulty sleeping , dizziness or lightheadedness and gastrointestinal symptoms . Children who had experienced upper respiratory infection ( URI ) within the 7 days before their trek tended to have a greater risk for development of AMS . AMS incidence did not significantly differ according to gender , recent acute gastroenteritis , menstruation and body mass index . CONCLUSIONS The incidence of AMS in children trekking on Jade Mountain is greater than that observed in adults , and was associated with altitude and recent URI AIM To investigate the effect of ginkgo biloba extract ( EGb 761 ) on lung injury induced by intestinal ischemia/reperfusion ( II/R ) . METHODS The rat model of II/R injury was produced by  clamping  the superior mesenteric artery for 60 min followed by reperfusion for 180 min . The rats were r and omly allocated into sham , II/R , and EGb + II/R groups . In EGb + II/R group , EGb 761 ( 100 mg/kg per day ) was given via a gastric tube for 7 consecutive days prior to surgery . Rats in II/R and sham groups were treated with equal volumes of the vehicle of EGb 761 .  Lung injury was assessed by light microscopy , wet-to-dry lung weight ratio ( W/D ) and pulmonary permeability index ( PPI ) . The levels of malondialdehyde ( MDA ) and nitrite/nitrate ( NO2(-)/NO3(- ) ) , as well as the activities of superoxide dismutase ( SOD ) and myeloperoxidase ( MPO ) were examined . Western blot was used to determine the expression of inducible nitric oxide synthase ( iNOS ) . RESULTS EGb 761 markedly improved mean arterial pressure and attenuated lung injury , manifested by the improvement of histological changes and significant decreases of pulmonary W/D and PPI ( P < 0.05 or 0.01 ) . Moreover , EGb 761 markedly increased SOD activity , reduced MDA levels and MPO activity , and suppressed NO generation accompanied by down-regulation of iNOS expression ( P < 0.05 or 0.01 ) . CONCLUSION The results indicate that EGb 761 has a protective effect on lung injury induced by II/R , which may be related to its antioxidant property and suppressions of neutrophil accumulation and iNOS-induced NO generation . EGb 761 seems to be an effective therapeutic agent for critically ill patients with respiratory failure related to Abstract Objective To evaluate the efficacy of ginkgo biloba , acetazolamide , and their combination as prophylaxis against  acute mountain sickness . Design Prospect i ve , double blind , r and omised , placebo controlled trial . Setting Approach to Mount Everest base camp in the Nepal Himalayas at 4280 m or 4358 m and study end point at 4928 m during October and November 2002 . Participants 614 healthy western trekkers ( 487 completed the trial ) assigned to receive ginkgo , acetazolamide , combined acetazolamide and ginkgo , or placebo , initially taking at least three or four doses before continued ascent . Main outcome measures Incidence measured by Lake Louise acute mountain sickness score ≥ 3 with headache and one other symptom . Secondary outcome measures included blood oxygen content , severity of syndrome ( Lake Louise scores ≥ 5 ) , incidence of headache , and severity of headache . Results Ginkgo was not significantly different from placebo for any outcome ; however participants in the acetazolamide group showed significant levels of protection . The incidence of acute mountain sickness was 34 % for placebo , 12 % for acetazolamide ( odds ratio 3.76 , 95 % confidence interval 1.91 to 7.39 , number needed to treat 4 ) , 35 % for ginkgo ( 0.95 , 0.56 to 1.62 ) , and 14 % for combined ginkgo and acetazolamide ( 3.04 , 1.62 to 5.69 ) . The proportion of patients with increased severity of acute mountain sickness was 18 % for placebo , 3 % for acetazoalmide ( 6.46 , 2.15 to 19.40 , number needed to treat 7 ) , 18 % for ginkgo ( 1 , 0.52 to 1.90 ) , and 7 % for combined ginkgo and acetazolamide ( 2.95 , 1.30 to 6.70 ) . Conclusions When compared with placebo , ginkgo is not effective at preventing acute mountain sickness . Acetazolamide 250 mg twice daily afforded robust protection against symptoms of acute mountain sickness Acetazolamide and gingko biloba are the two most investigated drugs for the prevention of acute mountain sickness ( AMS ) . Evidence suggests that they may also reduce pulmonary artery systolic pressure ( PASP ) . To investigate whether these two drugs for AMS prevention also reduce PASP with rapid airlift ascent to high altitude , a r and omized controlled trial was conducted on 28 healthy young men with acetazolamide ( 125 mg bid ) , gingko biloba ( 120 mg bid ) , or placebo for 3 days prior to airlift ascent ( 397 m ) and for the first 3 days at high altitude ( 3658 m ) . PASP , AMS , arterial oxygen saturation ( Sao2 ) , mean arterial pressure ( MAP ) , heart rate ( HR ) , forced vital capacity ( FVC ) , forced expiratory volume in the first second ( FEV1 ) , and peak expiratory flow ( PEF ) were assessed both at 397 m and 3658 m. HR , PEF , and PASP increased with altitude exposure ( p<0.05 ) , and SaO2 decreased ( p<0.05 ) . PASP with acetazolamide ( mean at 3658 m , 26.2 mm Hg ; incremental change , 4.7 mm Hg , 95 % CI . , 2.6 - 6.9 mm Hg ) was lower than that with ginkgo biloba ( mean at 3658 m , 33.7 mm Hg , p=0.001 ; incremental change , 13.1 mm Hg , 95%CI . , 9.6 - 16.5 mm Hg , p=0.002 ) , and with placebo ( mean at 3658 m , 34.7 mm Hg , p<0.001 ; 14.4 mm Hg , 95 % CI . , 8.8 - 20.0 mm Hg , p=0.001 ) . The data show that a low prophylactic dosage of acetazolamide , but not gingko biloba , mitigates the early increase of PASP in a quick ascent profile Previous studies suggest that 5 days of prophylactic ginkgo decreases the incidence of  acute mountain sickness ( AMS )  during gradual ascent . This trial was design ed to determine if ginkgo is an effective prophylactic agent if begun 1 day prior to rapid ascent . In this double-blind , r and omized , placebo-controlled trial , 26 participants residing at sea level received  ginkgo ( 60 mg TID ) or placebo starting 24 h before ascending Mauna Kea , Hawaii . Subjects were transported from sea level to the summit ( 4205 m ) over 3 hours , including 1 hour at 2835 m. The Lake Louise Self-report Question naire constituted the primary outcome measure at baseline , 2835 m , and after 4 h at 4205 m. AMS was defined as a Lake Louise Self-report Score ( LLSR ) > /= 3 with headache . Subjects who developed severe AMS were promptly transported to lower altitude for the remainder of the study . The  ginkgo ( n = 12 ) and placebo ( n = 14 ) groups were well matched ( 58 % vs. 50 % female ; median age 28 yr , range 22 - 53 vs. 33 yr , range 21 - 53 ; 58 % vs. 57 % Caucasian ) . Two ( 17 % ) subjects on ginkgo and nine ( 64 % ) on placebo developed severe AMS and required descent for their safety ( p = 0.021 ) ; all recovered without sequelae . Median LLSR at 4205 m was significantly 
    Output:
    
The currently available data suggest that although GBE may tend towards AMS prophylaxis , there are not enough data to show the statistically significant effect of GBE on preventing AMS .