***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    Input: On the basis of previously unpublished observations , we hypothesized that prolonged use of proton pump inhibitors ( PPIs ) causes an increase in 99mTc-sestamibi uptake in the stomach wall , manifested as curvilinear activity surrounding the photopenic fundus of the stomach cavity . We prospect ively evaluated the frequency of stomach wall uptake in patients undergoing myocardial perfusion SPECT who were taking PPIs or H2 antagonists .  Methods : Patients ( n = 138 ) who were scheduled for single-day rest/stress 99mTc-sestamibi SPECT were r and omly selected .  Poststress SPECT was performed 30 min after treadmill exercise or 45 min after dipyridamole infusion . The rest scan was obtained 45 min after tracer injection . All patients drank 473 mL of water 5–10 min after both the rest and the stress radiotracer injections . Patients were question ed regarding their use of PPIs and H2 antagonists . The significant use of either was defined as more than 2 wk of continuous therapy before cardiac SPECT . Masked observers assessed poststress planar projection images in endless-loop cinematic format for the following 3 patterns : stomach cavity uptake , attributable to duodenogastric reflux of tracer ; stomach wall uptake ; and no stomach uptake . A 2-tailed χ2 test with Yates correction was used to calculate statistically significant associations among variables . Results : Only patients with observed patterns of stomach wall uptake ( n = 30 ) and no stomach wall uptake ( n = 91 ) were included . Patients with stomach cavity uptake ( n = 17 ) were excluded because the assessment of the adjacent stomach wall uptake was not possible . Of the patients included ( n = 121 ) , 30 were men and 91 were women . Sixty-seven patients were older than 60 y ; 26 patients were taking PPIs . Of the 95 patients not taking PPIs  , 14 were taking H2 antagonists . No patients were taking both medications . Stomach wall uptake was strongly associated with prolonged use of PPIs ( χ2 = 51.9 , P < 0.0001 ) . No statistically significant association was noted among age , sex , or use of H2 antagonists ( P = NS ) . Conclusion : Prolonged PPI therapy , but not H2 antagonist therapy , contributes to a significant increase in stomach wall activity , potentially result ing in Compton scatter or ramp filter artifacts affecting the inferior wall of the left ventricle . Stomach wall activity , unlike the stomach cavity activity , can not be prevented by the ingestion of water before imaging . Therefore , it is important to elicit a history of prolonged PPI use to better anticipate the possibility of increased stomach wall activity , which can confound the image quality and interpretation Little is known about healing or recurrence of aspirin-induced gastric  ulcers if aspirin intake is continued . A double-blind controlled study compared cimetidine plus antacids as needed ( prn ) with placebo plus prn antacids in healing  aspirin-associated gastric ulcers  during continued salicylate ingestion in 18 rheumatic disease patients over a 2-month period .  Healing occurred in 44 % of the placebo and 56 % of the cimetidine-treated patients ( P>0.05 ) . Subjects in both groups ingested potentially therapeutic doses of antacid .  Ulcer size had an effect on healing rate , irrespective of treatment . Ninety percent of gastric ulcers<0.5 cm in diameter healed in 2 months but only 25 % of ulcers>0.5 cm . Six of seven patients with unhealed ulcers at 2 months eventually healed medically at intervals of 6–26 months . Of 11 patients managed medically and followed endoscopically for a mean of 15 months after healing , only one had a recurrent ulcer . In conclusion , placebo and antacid therapy were as effective as cimetidine and antacids in healing ulcers over a 2-month period . In spite of continued aspirin intake , most benign gastric ulcers < 0.5 cm in diameter heal medically in two months .  Aspirin-induced ulcers≥1 cm in diameter are relatively resistant to therapy but can be healed with prolonged cimetidine and antacid treatment ; once healed , recurrence rate is low with prophylactic therapy even with continued aspirin intake AIM To assess benefit versus harm of aspirin for cardiovascular disease ( CVD ) primary prevention by age group , gender and risk category and to interpret these results in light of current New Zeal and CVD risk assessment and management guidelines . METHODS Rates of benefit ( avoided vascular events ) and harm ( additional major extracranial bleeds ) for each gender and age group were calculated from data from the six r and omised controlled trials included in the Anti-Thrombotic Trialists ' ( ATT ) Collaboration meta- analysis . These rates were applied to CVD risk categories to calculate the net benefit or net harm likely to occur from the use of aspirin in primary prevention of CVD as monotherapy and when added to lipid and blood pressure-loweringtherapies . RESULTS Benefits of aspirin monotherapy outweigh the harms for both men and women aged up to 80 years with calculated five-year CVD risk > 15 % in primary prevention . Harm may outweigh benefit for primary prevention for those over 80 years . For men 70 - 79 years the benefit of aspirin in primary prevention is marginal when added to lipid and blood pressure-lowering therapies . DISCUSSION The recent ATT Collaboration meta- analysis has raised doubts about the relative safety of aspirin in primary prevention of CVD . However , modelling by risk category and age group suggests that current guidelines are justified in recommending aspirin for primary prevention of CVD in those with five-year CVD risk > or = 15 % up to the age of 80 years . For men 70 - 79 , consider lipid and blood pressure-lowering therapies first then reassess whether aspirin adds additional net benefit A r and omized , double-blind , placebo-controlled study examined whether concomitant administration of ranitidine could protect against the gastroduodenal  mucosal damage associated with long-term aspirin therapy in healthy men . Twenty-four subjects received ranitidine ( 150 mg twice daily ) plus aspirin ( 650 mg four times daily ) , and 19 received placebo twice daily plus aspirin ( 650 mg four times daily ) for four weeks . Gastric injury and duodenal injury were assessed separately according to a numerical rating scale for incidence and severity of lesions observed during endoscopic examinations at baseline and after four weeks of treatment . The ranitidine/aspirin group had significantly less mucosal damage in the stomach and duodenum than the placebo/aspirin group . Mean serum salicylate levels were similar between treatment groups after two and four weeks of aspirin therapy . Therefore , the protective effect of ranitidine was achieved with no compromise in salicylate absorption BACKGROUND There are few therapeutic options for the prevention of gastrointestinal mucosal damage caused by low-dose aspirin . We therefore investigated the efficacy of famotidine , a well-tolerated histamine H(2)-receptor antagonist , in the prevention of peptic ulcers and erosive oesophagitis in patients receiving low-dose aspirin for vascular protection . METHODS Adult patients ( aged > /=18 years ) from the cardiovascular , cerebrovascular , and diabetes clinics at Crosshouse Hospital , Kilmarnock , UK , were eligible for enrolment in this phase III , r and omised , double-blind , placebo-controlled trial if they were taking  aspirin 75 - 325 mg per day with or without other cardioprotective drugs .  Patients without ulcers or erosive oesophagitis on endoscopy at baseline were r and omly assigned by computer-generated r and omisation sequence to receive famotidine 20 mg twice daily ( n=204 ) or placebo twice daily ( n=200 ) . Patients had a final endoscopic examination at 12 weeks . The primary endpoint was the development of new ulcers in the stomach or duodenum or erosive oesophagitis at 12 weeks after r and omisation . Analysis was by intention to treat , including all r and omised patients who received at least one dose of study drug ( famotidine or placebo ) . This trial is registered as an International St and ard R and omised Clinical Trial , number IS RCT N96975557 . FINDINGS All r and omised patients received at least one dose and were included in the ITT population . 82 patients ( famotidine , n=33 ; placebo , n=49 ) did not have the final endoscopic examination and were assumed to have had normal findings ; the main reason for participant withdrawal was refusal to continue . At 12 weeks , comparing patients assigned to famotidine with patients assigned to placebo , gastric ulcers had developed in seven ( 3.4 % ) of 204 patients compared with 30 ( 15.0 % ) of 200 patients ( odds ratio [ OR ] 0.20 , 95 % CI 0.09 - 0.47 ; p=0.0002 ) ; duodenal ulcers had developed in one ( 0.5 % ) patient compared with 17 ( 8.5 % ; OR 0.05 , 0.01 - 0.40 ; p=0.0045 ) ; and erosive oesophagitis in nine ( 4.4 % ) compared with 38 ( 19.0 % ; OR 0.20 , 0.09 - 0.42 ; p<0.0001 ) , respectively . There were fewer adverse events in the famotidine group than in the placebo group ( nine vs 15 ) ; four patients in the placebo group were admitted to hospital with upper gastrointestinal haemorrhage . The other most common adverse event was angina  ( famotidine , n=2 ; placebo , n=4 ) . INTERPRETATION Famotidine is effective in the prevention of gastric and duodenal ulcers , and erosive oesophagitis in patients taking low-dose aspirin .  These findings widen the therapeutic options for the prevention of gastrointestinal damage in patients needing vascular protection . FUNDING Merck Laboratories and Astellas Pharma OBJECTIVE To compare the efficacy and safety of long term use of ranitidine 150 mg bid , 300 mg bid and placebo in prevention of endoscopic and symptomatic relapse of reflux esophagitis in an international , double-blind , placebo controlled , parallel group study . PATIENTS AND METHODS A total of 279 patients at least 18 years old from hospital out-patient departments with healed esophagitis ( grade 0 ) with no or mild symptoms entered the study . Patients were r and omly allocated to receive ranitidine 150 mg , 300 mg placebo twice daily for 48 weeks . Patients returned for symptom assessment s at eight-week intervals and for re-endoscopy every 16 weeks . RESULTS Both ranitidine regimens were significantly more effective than placebo in preventing endoscopic and symptomatic relapse of reflux esphagitis ( p = 0.003 for ranitidine 150 mg bid ; P < 0.001 for ranitidine 300 mg bid ) . No statistically significant differences were observed in relapse rates between the two ranitidine regiments . The percentage of patients with endoscopic relapse ( grade 2 ) after 48 weeks were 60 % , 37 % and 27 % for placebo , ranitidine 150 mg bid and ranitidine 300 mg bid , respectively ( P = 0.002 for ranitidine 150 mg bid versus placebo ; P < 0.001 for ranitidine 300 mg bid versus placebo ) . Ranitidine was well tolerated . CONCLUSIONS Ranitidine 150 mg bid and 300 mg bid are safe and effective treatments in the prevention of reflux esophagitis relapse 
    Output:
    
INTERPRETATION H2 blockers reduced gastrointestinal harm among patients taking ASA for 2 weeks or longer .