***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: Publisher Summary This chapter focuses on the bias in analytic research .  Case-control studies are attractive . They can be executed quickly and at low cost , even when the disorders of interest are rare . The execution of pilot case-control studies is becoming automated ; strategies have been devised for the “ computer scanning ” of large files of hospital admission diagnoses and prior drug exposures , with detailed analyses carried out in the same data set on an ad hoc basis . As evidence of their growing popularity , when one original article was r and omly selected from each issue of The New Engl and Journal of Medicine , The Lancet , and the Journal of the American Medical Association for the years 1956 , 1966 , and 1976 , the proportion that reported case-control analytic studies increased fourfold over these two decades ; however , the proportion reporting cohort analytic studies fell by half ; a general trend toward fewer study subjects but more study authors was also noted BACKGROUND Homeopathic pathogenetic trials ( HPTs ) ( provings ) are the pillar of homeopathy . Symptoms experienced by healthy volunteers are used to find the correct medicine for therapy . It is unclear whether these symptoms are specific or due to placebo noise . Furthermore , it is uncertain whether proving effects , if present at all , are due to a local or non-local process OBJECTIVES To develop a test model which allows for testing if homeopathic proving symptoms are caused by placebo or causative mechanisms , and if these symptoms are due to local or non-local processes . DESIGN R and omised , blinded , placebo-controlled , parallel-group study , with 1-week baseline and 2-weeks proving period . SUBJECTS 11 healthy volunteers from two different homeopathic schools . PROVING SUBSTANCE : An homeopathic medicine ( Cantharis 30c ) , blindly chosen from 12 potential medicines , compared to placebo . OUTCOME MEASURE Number of symptoms typical for the medicine in the experimental and control group during baseline and proving period . RESULTS During baseline there was no difference in the number of typical or atypical symptoms in either group . During the proving period , both more typical symptoms for Cantharis ( P= 0.03 ) and more atypical symptoms ( P= 0.02 ) were observed compared to baseline . Between-group differences were not significant . Effect sizes for the difference between the proving and control group for typical symptoms was d=0.4 , and for atypical symptoms d=0.6 . DISCUSSION This proving model could be valuable in study ing the validity of proving symptoms of homeopathic substances in healthy volunteers . CONCLUSION Homeopathic proving symptoms appear to be specific to the medicine and do not seem to be due to a local process . Since this was a pilot study using a small number of provers , rival hypotheses can not be ruled out and the study needs replication Two homeopathic pathogenetic trials ( HPTs , provings ) , of identical design were conducted : of Acidum malicum 12 cH and Acidum ascorbicum 12 cH. Each trial included 20 healthy volunteers . Both were of double-blind , placebo-controlled , r and omised , four period crossover design , with two sequences . ' Healthy ' was defined in terms of SF-36 scores , medical judgement and blood tests . All volunteers had regular interviews with the same supervisor . No serious adverse reactions occurred . The causal relationship of each symptom with treatment was judged , blind , by the volunteer , the supervisor and a 9-item pathogenetic index . For Acidum malicum 79 symptoms were identified by the supervisor , 57 were included in the final analysis , 22 occurred in verum treatment periods . For Acidum ascorbicum , of 55 symptoms , 39 were included in the analysis . 16 occurred in verum treatment periods The occurrence of a nocebo effect after placebo administration to healthy volunteers in a Phase I trial was analysed according to their type of personality ( Bortner Rating Scale ) . More subjects with a behaviour pattern A ( competitive and aggressive ) ( 50 % ) described subjective side effects of the placebo than type B subjects ( 17 % , P = 0.03 ) . The volunteers who had nocebo effect had a higher Bortner score ( BS ) than did placebo non-responsive subjects ( P = 0.05 ) . The BS was 205 for paramedical staff , 189 for medical and dentistry students , 173 for non-science students and 161 for science students ( P < 0.04 ) . The nocebo response was not statistically correlated with professional status . These results suggest that volunteer 's type of personality might influence the reporting of subjective symptoms after placebo , and therefore impair the evaluation of new drugs in Phase I clinical trials AIMS To investigate if ultramolecular homeopathy has any clinical effects . This was assessed using the proving of the homeopathic remedy Belladonna given at an ultramolecular dose ( 30C ) , as a model . A proving states that when a homeopathic remedy is given to a healthy person , they will experience symptomatic effects specific to that remedy . If ultramolecular doses are clinical ly active , the Belladonna 30C group should experience more true Belladonna proving symptoms than the placebo group . METHODS Healthy subjects ( n = 253 ) , aged 18 - 30 years , took part in this double-blind , r and omized  placebo-controlled study . Total study duration was 4 weeks . Subjects were r and omized before 1 week placebo run-in . They received 2 weeks of treatment intervention ( Belladonna 30C or placebo ) and were followed up for 1 week . Subjects recorded any symptoms experienced during the total study period on a daily basis using a structured question naire . Symptom diaries were analysed blind to determine if each subject had proved or not ( based on predefined criteria ) . The main outcome was the proportion of subjects who had proved in each treatment group . RESULTS No significant group differences in proving rates were observed [ Belladonna provers N = 14 ( 13.9 % ) ; placebo provers N = 15 ( 14.3 % ) ; mean difference -0.4 % , 95 % confidence interval -9.3 , 10.1 ] based on intention to treat analysis . Primary outcome was not affected by seasonality or the individual 's attitude to complementary medicine . CONCLUSION Ultramolecular homeopathy had no observable clinical effects Abstract Healthy university students and hospital staff taking no medications  were surveyed by question naire to obtain data on the occurrence of many symptoms often listed as side effects of drugs Two experiments ( N=56 ) investigated the relationship between subjects ’ expectancies concerning the effect of caffeine on a motor skill , and the type of placebo response . Male subjects were assigned to four groups . Three groups expected to receive caffeine but received a placebo . Prior to the placebo , two of the groups received information about the effect of caffeine on a motor skill task which led one group E(+ ) to expect enhanced performance , and the other E(− ) to expect impairment . The third placebo group received no information E ( ? ) . A control group E(0 ) received no beverage , so neither caffeine nor any effect on performance was expected . The expected type of effect predicted the type of placebo response displayed . Group E(+ ) displayed greater improvement under placebo than did group E(0 ) , and group E(− ) performed more poorly than those in group E(0 ) . No placebo response was observed in group E ( ? ) . Placebo effects on mood were correlated with subjects ’ predictions about the effect of caffeine on mood . The role of expectancies in response to placebos and psychoactive drugs is discussed Abstract A class experiment for medical students Summary was devised to demonstrate the influence of the placebo effect and non-drug factors on response to drugs . The subjects were conditioned to expect sedative or stimulant effects , but all received placebo in one or two blue or pink capsules . Predictions about the size and nature of the placebo response and influence of the non-drug factors were made before the experiment and discussed afterwards . Four of six predictions were fully confirmed . Drug- associated changes were reported by 30 % of the subjects and were severe in 1 or 2 individuals . Two capsules produced more noticeable changes than one , and blue capsules were associated with more sedative effects than pink capsules . Students rated the experiment highly both as a learning experience and for its relevance to their future practice of medicine 
    Output:
    
More symptoms were reported from HPTs of poor quality than from better ones .
The HPTs were generally of low method ological quality .
There is a high incidence of pathogenetic effects in publications and volunteers but this could be attributable to design flaws .
Homeopathic medicines , tested in HPTs , appear safe .