***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: From a review of thirty published papers it is clear that the variety of options for treatment of  hepatitis B  have led to a large number of small exploratory trials . However , small groups lead to imprecise estimates of seroconversion rates ; for example a result of 4/10 gives an estimate of 40 % with 80 % confidence limits of 20 % and 60 % . A number of possible prognostic factors have been proposed and , whilst their importance is generally unproven , their estimated effects are considerable . Comparison between studies can therefore be misleading ; for example comparing two treatments A and B of identical efficacy in two common population s could give a 1 in 4 chance of declaring B to give double the seroconversion rate of A. Larger , r and omised , controlled trials on homogeneous patient groups are needed to give conclusive evidence of the efficacy or otherwise of various treatment regimes R and omized clinical trials ( RCTs ) provide the most reliable therapeutic information available . Unfortunately , there are no systemic listing of RCTs . We compared a MEDLARS search of 3686 biomedical journals for RCTs with a manual search of the medical literature for the period 1966 - 1982 . For the former search we used subject headings ( 1 ) liver disease or ( 2 ) biliary tract disease and subheadings ( 1 ) drug therapy , ( 2 ) surgery , ( 3 ) radiotherapy , or ( 4 ) therapy , and check tags ( 1 ) comparative study or ( 2 ) clinical research . For the manual search , the contents of 34 arbitrarily selected , gastroenterologic , hepatologic , surgical , or general journals were perused . The MEDLARS search identified 160 RCTs and 29 others were found in the references of the 160 . One hundred fifty-four RCTs were identified by both methods . The manual search identified 208 RCTs and an additional 34 were found in the references of the 208 . The MEDLARS search identified only 107 of 208 RCTs found in the references of the 208 . The MEDLARS search identified only 107 of 208 RCTs found manually in the 36 journals , an efficiency rate of 51 % . We estimate that 330 hepatobiliary RCTs had been published during this 17-year period . Sixty percent of the RCTs found by MEDLARS used the key word " r and omized , " " double blind , " or " controlled " in the title , compared to 36 % in those found by the manual search . In order to retrieve RCTs , it is essential that editors require that RCTs be identified in their titles or key words by specific terms such as " controlled , " " r and omized , " and " double blind , " that papers be so catalogued and indexed , and that search ers be instructed in appropriate search strategies In a double-blind study human leucocyte interferon was given for six weeks to 8 of 16 patients with chronic HBsAg-positive hepatitis . In the first week 12 x 10(6 ) reference units were administered daily , and thereafter the dose was halved every week . During the first two weeks leucopenia was observed in 6 of the 8 interferon-treated patients . Apart from a drop in DNA-polymerase activity in the first week , no effect was found on indices of hepatitis-B-virus infection THE R AND OMIZED controlled trial ( RCT ) , more than any other methodology , can have a powerful and immediate impact on patient care . Ideally , the report of such an evaluation needs to convey to the reader relevant information concerning the design , conduct , analysis , and generalizability of the trial . This information should provide the reader with the ability to make informed judgments regarding the internal and external validity of the trial . Accurate and complete reporting also benefits editors and review ers in their deliberations regarding su bmi tted manuscripts . For RCTs to ultimately benefit patients , the published report should be of the highest possible st and ard A grid devised to evaluate the method ological quality of  r and omized therapeutic trials is presented . Fourteen items are analysed : description of the principal criterion of assessment , criteria of inclusion , number of subjects seen and excluded , number of subjects r and omized to each group , number of subjects excluded who are alive or lost to follow-up and reasons for the fall-outs , blind character of the doctors , patients and persons responsible for the assessment criteria , calculation of the number of subjects required before starting the trial , method of r and omization and its blind character , analysis and discussion of covariables , statistical tests used , taking into account of the fall-outs and power of the trials with non-significant results . This grid , used for the analysis of 527 r and omized trials , showed that about one-half of them were of mediocre quality , the most frequent defects encountered being the multiplicity of assessment criteria , the lack of description of the subjects excluded , the absence of calculation of the number of subjects required before starting the trial and the small number of subjects in trials with non-significant results 46 male chronic hepatitis B virus ( HBV ) carriers with active viral replication were r and omised , with stratification for histology and sexual preference , to receive six months ' lymphoblastoid interferon or no therapy . After nine to eighteen months ' follow-up , HBeAg was no longer detectable and anti-HBe was present in 6 of the 23 treated patients .  HBsAg was not detectable in 5 of these patients and 3 had anti-HBs . All of the controls remained positive for HBeAg and HBsAg . Seroconversion from HBeAg to anti-HBe was preceded in all cases by a pronounced increase in serum aspartate aminotransferase levels of more than ten times the upper limit of normal at eight to twelve weeks ; this response was exclusively associated with interferon therapy . These results suggest that loss of HBsAg and a hepatitis-like illness in the third month of therapy are direct effects of interferon treatment BACKGROUND & AIMS Long-term ursodeoxycholic acid ( UDCA ) therapy slows the progression of primary biliary cirrhosis . This study examined the effect of UDCA therapy on survival free of liver transplantation in a large group of patients . METHODS Data from three clinical trials were combined in which patients with primary biliary cirrhosis were r and omly assigned to receive UDCA ( n = 273 ) or placebo ( n = 275 ) . After 2 years , patients from French and Canadian studies received UDCA for up to 2 years . Patients from the American study remained on their assigned treatment for up to 4 years . RESULTS Survival free of liver transplantation was significantly improved in the patients treated with UDCA compared with the patients originally assigned to placebo ( P < 0.001 ; relative risk , 1.9 ; 95 % confidence interval , 1.3 - 2.8 ) . Subgroup analyses showed that survival free of liver transplantation was significantly improved in medium- and high-risk groups ( serum bilirubin level , 1.4 to 3.5 or > 3.5 mg/dL ; P < 0.0001 and P < 0.03 , respectively ) and histological stage IV subgroup ( P < 0.01 ) . CONCLUSIONS Long-term UDCA therapy improves survival free of liver transplantation in patients with moderate or severe disease . An effect in patients with mild disease is probably not found because they do not progress to end-stage disease in 4 years Forty-five patients with chronic hepatitis B were entered into a r and omized controlled trial of recombinant human alpha-interferon therapy .  All patients had hepatitis B surface antigen in serum for at least 1 yr and had stable serum levels of both hepatitis B virus deoxyribonucleic acid and hepatitis B e antigen . During the 4-mo period of therapy , 10 of 31 ( 32 % ) treated patients and only 1 of 14 ( 7 % ) control patients became negative for serum hepatitis B virus deoxyribonucleic acid and deoxyribonucleic acid polymerase . All 10 patients who became negative for serum hepatitis B virus deoxyribonucleic acid subsequently had a marked improvement in serum aminotransferase activities and lost hepatitis B e antigen from serum , and 9 of them had improvement in liver histology . Comparison of responders to nonresponders indicated that female sex and a high initial level of serum aspartate aminotransferase correlated best with response to interferon therapy . These findings indicate that a 4-mo course of recombinant alpha-interferon can induce a remission in disease in approximately one-third of patients with chronic hepatitis 
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The second hypothesis was that survival of truth should be higher for negative conclusions than for positive conclusions .
A negative conclusion has a better chance of survival because the only way it would not continue to be negative is if it were found to be false .
A positive conclusion risks being found to be false or becoming obsolete .
Conclusions from older research are at greater risk for being refuted or becoming obsolete than are conclusions from more recent studies .