***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: OBJECTIVES : Little is known about missed rates of upper gastrointestinal cancer ( UGC ) in Western population s , with most data originating from Japanese centers quoting high missed rates of 23.5–25.8 % . The objective of this study was to better define missed rates of esophagogastroduodenoscopy ( EGD ) and the natural history of UGC in a Western population that underwent an initial EGD  without cancer , but were subsequently diagnosed with a UGC . Our hypothesis was that a normal EGD rarely misses the detection of UGC . METHODS : This is a retrospective cohort study . A prospect ively maintained electronic data base was used to identify all patients who underwent EGD between 1990 and 2004 at the study institution . Patients in this cohort who were diagnosed with UGC before 2006 were identified through the Western Australian Cancer Registry . We defined missed cancers as those diagnosed within 1 year of EGD , possible missed cancers as those diagnosed 1–3 years after EGD , and new cancers as those diagnosed more than 3 years after EGD . This study had no interventions and was conducted at a tertiary referral center . The main outcome measurement included UGC . RESULTS : Of the 28,064 EGDs performed , UGC was diagnosed subsequent to the procedure in 116 cases ( 0.41 % ) . There were 29 missed cancers , 26 possible missed cancers , and 75 new cancers . Of the missed cancers , 11 were esophageal , 15 were gastric , and 3 were duodenal . In 69 % ( n=20 ) of the missed cancers , an abnormality was described at the site of malignancy . In 59 % ( n=17 ) of the missed cancers , the indication for EGD was an alarm symptom of dysphagia or suspected blood loss . In an univariate analysis , the presence of an alarm symptom was related to missed cancers , whereas operator experience , trainee participation , and usage of newer equipment were not . One of the main limitations of this study is that it was a retrospective review . CONCLUSIONS : UGC is rare after normal EGD , confirming the high accuracy of EGD . Institutional approval was granted for the conduct of this study A system has been constructed to evaluate the design , implementation , and analysis of  r and omized control trials ( RCT ) . The degree of quadruple blinding ( the r and omization process , the physicians and patients as to therapy , and the physicians as to ongoing results ) is considered to be the most important aspect of any trial . The analytic techniques are scored with the same emphasis as is placed on the control of bias in the planning and implementation of the studies . Description of the patient and treatment material s and the measurement of various controls of quality have less weight . An index of quality of a RCT is proposed with its pros and cons . If published papers were to approximate these principles , there would be a marked improvement in the quality of r and omized control trials . Finally , a reasonable st and ard design and conduct of trials will facilitate the interpretation of those with conflicting results and help in making valid combinations of undersized trials BACKGROUND AND AIM Upper GI endoscopy ( UGE ) is essential for the diagnosis of gastrointestinal diseases . Mucus and bubbles may decrease mucosal visibility . The use of mucolytics could improve visualization . Our aim was to determine whether premedication with simethicone or simethicone plus N-acetylcysteine is effective in improving visibility during UGE . METHODS This was a r and omized , double-blinded , placebo-controlled trial with 2 control groups : no intervention and water 100 mL ( W ) ; and 3 intervention groups : simethicone 200 mg ( S ) ; S + N-acetylcysteine ( NAC ) 500 mg ( S+NAC500 ) ; and S + NAC 1000 mg ( S+NAC1000 ) . The solution was ingested 20 minutes before UGE . Gastric visibility was evaluated in 4 segments with a previously described scale . A score of less than 7 points was defined as adequate visibility ( AV ) . Water volume was used to improve visibility , and adverse reactions were evaluated as a secondary outcome . Multiple group comparison was performed using non-parametric one-way analysis of variance ( ANOVA ) . RESULTS Two hundred thirty patients were included in the study , 68 % female , mean age 49 years . The most common indication for UGE was epigastric pain/dyspepsia ( 33 % ) .  AV was more frequent in the S+NAC500 and S+NAC1000 groups ( 65 % and 67 % ) compared with no intervention ( 44 % , P = .044 ) and water ( 41 % , P = .022 ) . The gastric total visibility scale ( TVS ) was significantly better in the S+NAC500 and S+NAC1000 groups compared with water ( P = .03 and P = .008 ) . Simethicone was not different from no intervention and water . S+NAC1000 required less water volume to improve visibility . No adverse reactions from the study drugs were observed . CONCLUSIONS Premedication with S+NAC500 and S+NAC1000 improves visibility during UGE . The use of simethicone did not show improvements in gastric visibility . TVS was worse in patients using water alone . ( Clinical trial registration number : NCT 01653171 . ) Background and study aim Upper endoscopy is the most common method for the diagnosis of upper gastrointestinal tract diseases . The aim of this study was to determine whether premedication with simethicone or N-acetylcysteine improves mucosal visualization during upper endoscopy . Patients and methods This was a r and omized , double-blind , placebo-controlled study of 297 patients scheduled for upper endoscopy who were premedicated 15 - 30 minutes before the procedure with : 100 mL of water ( placebo , group A ) ; water plus 100 mg simethicone  ( group B ) ; water plus 100 mg simethicone plus 600 mg N-acetylcysteine ( group C ) . The primary outcome measure was the quality of mucosal visualization ( score : excellent , adequate or inadequate ) . Results The addition of simethicone ( group B ) or simethicone plus N-acetylcysteine to the water ( group C ) improved the visualization scores of endoscopies compared with water alone ( group A ) . In particular , groups B and C produced a significantly higher percentage of endoscopies with excellent visualization for the esophagus ( 91.1 % and 86.7 % , respectively , vs. 71.4 % in group A ; P < 0.001 ) and stomach ( 76.2 % and 74.5 % vs. 38.8 % in group A ; P < 0.001 ) . For the duodenum , the use of simethicone also showed an increase in the endoscopies with excellent visualization compared with water alone ( 85.1 % vs. 73.5 % ; P = 0.042 ) . There were no significant differences in scores between groups B and C or between gastric scores in patients with previous subtotal gastrectomy ( B and C vs. A ) : 60.0 % and 42.1 % vs. 28.6 % ( P = 0.14 ) . The rate of reported lesions was higher in group B but without statistical significance . Conclusions Premedication with simethicone result ed in better mucosal visibility . Such premedication might improve diagnostic yield , and should be considered for st and ard practice . Trial registered at Clinical Trials.gov ( NCT02357303 ) BACKGROUND Simethicone improves endoscopic visibility and diagnostic accuracy during colonoscopy and capsule endoscopy . Nevertheless , there have been limited data on its usefulness in esophagogastroduodenoscopy ( EGD ) . OBJECTIVE To evaluate the effectiveness of simethicone on enhancing endoscopic visibility in patients undergoing EGD . MATERIAL AND METHOD 121 patients were r and omized to take 2 ml ofeither liquid simethicone or placebo in 60 ml of water at 15 - 30 minutes before EGD . The severity scores of foam and bubbles at the esophagus , stomach and duodenum were compared . RESULTS Simethicone improved endoscopic visibility by diminishing mean cumulative ( 6.83 + /- 2.4 vs. 11.05 + /- 2.6 , p < 0.001 ) and local scores offoam and bubbles at all areas , and decreased the number and timing ofadjunctive simethicone washing ( 17.5 % vs. 74.1 % , p < 0.001 and 0 vs. 19 seconds , p < 0.001 ) . Simethicone increased endoscopist and patient satisfaction significantly without having adverse effects . CONCLUSION Using simethicone before EGD enhances endoscopic visibility , reduces adjunctive simethicone washing and increases endoscopist and patient satisfaction AIM To evaluate the efficacy of 5 mL simethicone solution in decreasing gastric foam if given at least 30 min before gastroscopy . METHODS This was a r and omized , placebo controlled , endoscopist blinded study performed at Changi General Hospital . Patients were at least 21 years old , had no prior surgical resection of the upper gastrointestinal tract , and scheduled for elective diagnostic gastroscopies . The primary outcome was the total mucosal visibility score ( TMVS ) which was evaluated using McNally score . The sample size was calculated to be 24 per group ( SD 2.4 , 80 % power , P < 0.05 , 2- sample t test ) . RESULTS Fifty-four patients were r and omised to receive either simethicone [ 1 mL liquid simethicone ( 100 mg ) in 5 mL of water ] or placebo ( 5 mL of water ) at least 30 min before their gastroscopy . Six accredited consultants conducted the gastroscopy , and the interobserver agreement of scoring TMVS was good with a Kappa statistic of 0.73 . The simethicone group had significantly better mean TMVS compared to placebo ( 5.78 ± SD 1.65 vs 8.89 ± SD 1.97 , P < 0.001 ) . The improvement was statistically significant for the duodenum and the gastric antrum , angularis , body , and fundus . Percent 51.9 of patients in the simethicone group had a TMVS of 4 ( no bubbles at all ) to 5 ( only 1 area with minimal bubbles ) , while in the placebo group 3.7 % of patients had TMVS of 4 or 5 . The number needed to treat was 2.1 to avoid a TMVS of 6 and more . The simethicone group also had a significantly shorter procedure time with less volume of additional flushes required during gastroscopy to clear away obscuring gastric foam . CONCLUSION With a premedication time of at least 30 min , 5 mL simethicone can significantly decrease gastric foam , decrease the volume of additional flushes , and shorten gastroscopy time OBJECTIVES To investigate whether a 360-degree horizontal turn after oral premedication with simethicone improves the mucosal visibility during gastroendoscopic examination , and to determine the proper time to turn over the patient . METHODS This study involved 993 patients scheduled for gastroendoscopy .  Just before gastroendoscopy , after oral premedication with simethicone , patients were r and omly assigned to three groups : in Group A , patients waited for 20 min before gastroendoscopy ; in Group B , patients were separately waited for 5/10/15/20 min and were then turned 360 degrees just before gastroendoscopy ; in Group C , patients were immediately turned 360 degrees and then separately waited for 5/10/15/20 min before examination . The sum of the gastric mucosal visibility scores ( MVS ) was calculated after the examination . The MVS and proportion of images with higher visibility scores for the mucosal surface . Lower scores indicate better visibility of the mucosal surface . RESULTS In Groups B and Groups C , when waiting time more than 10 min had lower mean total MVS than Group A. The MVS of four subgroups of Group B were not different from those of Group C. CONCLUSION Oral premedication with simethicone and immediately make a body posture change ( turning over 360 degrees ) then waiting for 10min can increase the image quality during gastroendoscopy and effectively decrease the premedication time AIM : To evaluate the effects of the various methods of small bowel preparation on the quality of visualization of the small bowel and the gastrointestinal transit time of capsule endoscopy ( CE ) . METHODS : Ninety patients referred for CE were prospect ively r and omized to three equal groups according to the preparation used : ( a ) a control group , in which patients were requested to drink 1 L of clear liquids only , 12 h before the examination ; ( b ) a purgative group , in which patients were requested to ingest 1 L of a polyethylene glycol (PEG)/electrolyte solution only , 12 h before the examination ; or ( c ) a purgative combined with simethicone group ( P-S group ) , in which patients were requested to ingest 1 L of PEG , 12 h before the examination , and 300 mg of simethicone , 20 min before the examination . Effects of the different bowel preparations on the gastric transit time ( GTT ) , small bowel trans 
    Output:
    
Conclusions The findings of current study on 1,099 patients successfully demonstrate that the pre-procedure oral administration of Simethicone ± N-acetylcysteine  improves mucosal visualization and mucosal visualization score during OGD