human
***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: We analysed self-reported cold data for 95 pairs of identical twins who took part in a double-blind trial of vitamin C tablets .  One member of each twin pair took vitamin C and the other took a well matched placebo each day for 100 days . Vitamin C had no significant effect except for shortening the average duration of cold episodes by 19 % Three hundred eleven employees of the National Institutes of Health volunteered to take 1 gm of ascorbic acid or lactose placebo in capsules three times a day for nine months . At the onset of a cold , the volunteers were given an additional 3 gm daily of either a placebo or ascorbic acid .  One hundred ninety volunteers completed the study . Dropouts were defined as those who missed at least one month of drug ingestion . They represented 44 % of the placebo group and 34 % of those taking ascorbic acid . Analysis of these data showed that ascorbic acid had at best only a minor influence on the duration and severity of colds , and that the effects demonstrated might be explained equally well by a break in the double blind During 7 weeks in the spring of 1973 a double-blind pilot study on 172 children in the age group 8 - 9 was carried out to test the possible effect of 1000 mg vitamin C daily as a prophylactic agent against common colds . During the autumn of 1973 , a main study was carried out on 642 children of the same age . The investigations had the same pattern and lasted for 3 months . Both studies have been processed on the same principles . The results were somewhat divergent but , like previously published studies on children , seemed to indicate that the duration and severity of the cold were reduced while , on the other h and , the incidence remained unaltered or indeed increased . The total number of days of upper respiratory tract infection was smaller for the vitamin C group only in the pilot study ( not in the main study ) . No proven biochemical effects were obtained . Preventive treatment of healthy children with vitamin C in large doses this had no definitely proved effect against colds METHOD A large number of women living in two towns in South Wales , and their husb and s , were asked to cooperate in the trial . These women had been identified several years previously in a study of child growth and nutrition and had already cooperated in a prophylactic trial of vitamin C ( Elwood et al. , 1975 ) . The subjects were visited in September and October and those who agreed were given ten effervescent tablets of either vitamin C ( 1 G ) or an inert ; placebo . Allocation of households to vitamin C or placebo was r and om , but each husb and received the same tablets as his wife . This was done to avoid confusion if tablets were shared . The smoking habit of each subject was recorded . Instructions were given that , when symptoms suggestive of a cold commenced , the tablets were to be started , three tablets per day until the 10 tablets had been taken . Symptoms were to be recorded each day for the duration of the cold . Sufficient detail was requested to enable colds to be classed as ‘ simple ’ , that is nasal symptoms with or without general symptoms such as fever or malaise but without any symptom referable to the chest such as cough . ‘ Chest ’ colds were recorded as any symptom-complex which included cough , wheezing , or other chest symptoms . A stamped addressed envelope was given to each subject for the return of the record card . An arbitrary date was chosen approximately six months after the trial commenced , and any subject who had not returned a A concentration of 15 pig/ml was arbitrarily taken as a level read.ly obtainable in h blood wiLh bo.h antibiotics . Th19 strains resistant to penicillin and tetracycline only were resis : ant to  tetracycline  in concentrations above 20 Ag/lml . This resis ance pattern occurs quite frequently in strains of S. aph . aureus isolated both from hospital patients and from the general comnnunity . It would appear therefore that any microbiological advantage which minocycline may exert over other tetracyclines is due to its sup rior activity against strains of Staph . aureus which are resistant to tetracycline . ' -I am , etc . , ARTHUR A. B. MITCHELL Bacteriology Department , Law Hospital , Carluke , Three different dosages of vitamin C , dependent on body weight , were administered to 44 school-aged monozygotic twins for five months using a double-blind , co-twin control study design . The mothers recorded daily observations of cold symptoms , and multiple biochemical , anthropometric , and psychological measurements were made at the beginning and end of the study . Paired comparisons showed no significant overall treatment effect on cold symptoms , but the response was not uniform in all sub-groups . Treated girls in the youngest two groups had significantly shorter and less severe illness episodes , and an effect on severity was also observed in the youngest group of boys . The seven treated twins in the latter group also grew an average of 1.3 cm more than their untreated co-twins during the five-minth period of the study A r and omized controlled trial of the effect of 1 g ascorbic acid per day in the prevention of the common cold was conducted on 688 adult women . There is evidence of a small reduction by  vitamin C  in the mean number of chest colds , but no evidence of any effect on simple colds . The existence of a subgroup of vulnerable women in the community who benefit from vitamin C was considered but further examination of the data gives no support to this conclusion A prospect i ve , r and omized , double-blind study was carried out to determine whether vitamin C prophylaxis , 2.0 g/day , vs placebo prophylaxis would reduce the incidence or morbidity of the common cold  and other respiratory illnesses in 674 marine recruits during an eight-week period . Whole-blood ascorbic acid levels measured six weeks after initiation of the study were significantly higher in the vitamin C group . There was no difference between the two groups in the incidence or duration of colds . The vitamin C group rated their colds as being less severe , but this was not reflected in different symptom complexes or in fewer sick-call visits or training days lost . This study and the literature do not support the prophylactic use of vitamin C to prevent the common cold OBJECTIVE To determine the effect of large doses of vitamin C in the treatment of the common cold . STUDY DESIGN Double-blind , r and omised clinical trial with four intervention arms : vitamin C at daily doses of 0.03 g ( " placebo " ) , 1 g , 3 g , or 3 g with additives ( " Bio-C " ) taken at onset of a cold and for the following two days . PARTICIPANTS AND SETTING 400 healthy volunteers were recruited from staff and students of the Australian National University , Canberra , ACT , between May 1998 and November 1999 . The trial continued for 18 months . INTERVENTIONS Participants were instructed to commence medication when they had experienced early symptoms of a cold for four hours , and to record daily their symptoms , severity , doctor visits and use of other medications . MAIN OUTCOME MEASURES Duration of symptoms and cold episodes ; cumulative symptom severity scores after 7 , 14 and 28 days ; doctor visits ; and whether participants guessed which medication they were taking . RESULTS 149 participants returned records for 184 cold episodes . No significant differences were observed in any measure of cold duration or severity between the four medication groups . Although differences were not significant , the placebo group had the shortest duration of nasal , systemic and overall symptoms , and the lowest mean severity score at 14 days , and the second lowest at 7 and 28 days . CONCLUSIONS Doses of vitamin C in excess of 1 g daily taken shortly after onset of a cold did not reduce the duration or severity of cold symptoms in healthy adult volunteers when compared with a vitamin C dose less than the minimum recommended daily intake A controlled study was made of the effects of natural orange juice , synthetic orange juice , and placebo in the prevention of the common cold ; both natural and synthetic orange juices contained 80 mg of ascorbic acid daily . Three-hundred sixty-two healthy normal young adult volunteers , ages 17 to 25 years , were studied for 72 days with 97 % of participants completing the trial . There was a 14 to 21 % reduction in total symptoms due to the common cold in the supplemented groups that was statistically significant ( P less than 0.05 ) . Ascorbic acid supplementation also increased the number of " episode-free " subjects . However , the clinical usefulness of the results does not support prophylactic ascorbic acid supplements in the well-nourished adult . The results in this study with both natural and synthetic orange juice of physiological content of ascorbic acid , are similar to those obtained using a " megadose " of ascorbic acid This study determined whether daily supplementation with 600 mg vitamin C would reduce the incidence of symptoms of  upper-respiratory-tract ( URT ) infections after participation in a competitive ultramarathon race ( > 42 km ) . Ultramarathon runners with age-matched controls were r and omly divided into placebo and experimental ( vitamin C-supplemented ) groups . Symptoms of URT infections were monitored for 14 d after the race . Sixty-eight percent of the runners in the placebo group reported the development of symptoms of URT infection after the race ; this was significantly more ( P < 0.01 ) than that reported by the vitamin C-supplemented group ( 33 % ) . The duration and severity of symptoms of URT infections reported in the vitamin C-supplemented nonrunning control group was also significantly less than in the nonrunning control group receiving the placebo ( P < 0.05 ) . This study provides evidence that vitamin C supplementation may enhance resistance to the postrace URT infections that occur commonly in competitive ultramarathon runners and may reduce the severity of such infections in those who are sedentary In a survey of double-bind design , 3 groups of approximately 70 student volunteers took 1 g L-ascorbic acid , 1 g D-isoascorbic acid , or placebo tablets every day for 15 weeks and the incidence and duration of colds were recorded . The group taking D-isoascrobic acid suffered 34 % fewer colds than the other two groups ; the results were also analyzed in relation to the sex and smoking habits of the volunteers . The rationale for investigating D-isoascorbic acid , an isomer of L-ascorbic acid which has limited antiscorbutic activity , is discussed Ascorbic acid is widely used as a prophylactic and therapeutic agent against the common cold , and is in fact often recommended for this purpose by medical practitioners . It may be administered as a large dose as soon as possible after the first symptoms are felt , and this dosage is then continued for a few days in order to " abort " the cold . Though many people use this treatment on themselves and believe it is effective , it is impossible to assess its efficacy . Untreated subjects may experience symptoms such as sneezing or a mild sore throat , which then disappear without going on to a full cold , and patients ' assessment s of their colds are much influenced by any treatment owing to the placebo effect ( Diehl et a/. , 1938 ) . In these studies we attempted to show by in-vitro experiments that exposure of cells to ascorbic acid increased their resistance to infection with viruses . Though there was no activity in vitro , we also attempted to demonstrate a protective effect in ftnmy»1 « or man , since it was thought that host resistance might be enhanced indirectly Self-reported cold data have been analyzed for 95 pairs of identical twins aged 14 - 64 who took part in a double-blind trial of vitamin C tablets .  One member of each twin pair took a tablet containing 1 g vitamin C and the other took a well-matched placebo each day for 100 days . In the total sample there was no effect of vitamin C in preventing colds . However , subdivision of the data showed a significant preventive effect of the placebo in the 51 pairs living together and an equal and opposite preventive effect of the vitamin C in the 44 pairs living apart . The placebo effect in the pairs living together may be attributed to the large proportion who wrongly perceived which treatment they were taking . The reduction of colds in the vitamin C group of the pairs living apart was about 20 % . There were significant correlations between cold symptoms reported and the personality trait of neuroticism . No side effects of substantive changes in serum biochemistry could be attributed to the vitamin C dose Abstract A double-blind study to evaluate vitamin C supplements for  respiratory-Infection prophylaxis  was conducted among 641 children at a Navajo boarding school over a 14-week period . Supplements The combination of a regular daily supplement of vitamin C with extra dosage at the time of illness has been shown to reduce the disability due to common colds and other winter illness , but we have seen little effect on frequency of infections , sense of ( well-being ) , or levels of serum cholesterol . The variable results that have been obtained from some other trials of vitamin C may be due in part to variation in the initial nutritional state of the subjects , with the greatest effects to be expected where there is most room for improvement . Because of the great variation in individual susceptibility to infection large numbers of subjects are required in these trials and they must be strictly double-blind . Although we have seen no clear evidence of harmful side-effects , occasional sensitivity to large doses of vitamin C can not be ruled out , and the withdrawal depression of blood levels could conceivably interfere with a patient 's ability to h and le stress A r and omised double-blind trial involving vitamin C/placebo supplementation was conducted on 57 elderly patients admitted to hospital with acute respiratory infections ( bronchitis and bronchopneumonia ) . Patients were assessed clinical ly and biochemically on admission and again at 2 and 4 weeks after admission having received either 20 
    Output:
    
agent
Vitamin C in doses as high as one gram daily for several winter months , had no consistent beneficial effect on incidence of the common cold .
For both preventive and therapeutic trials , there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms .
There was no clear indication of the relative benefits of different regimes or vitamin C doses .
However in trials that tested vitamin C after cold symptoms occurred , there was some evidence that a large dose produced greater benefits than lower doses .
REVIEW ER 'S CONCLUSIONS Long term daily supplementation with vitamin C in large doses daily does not appear to prevent colds .
***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: We analysed self-reported cold data for 95 pairs of identical twins who took part in a double-blind trial of vitamin C tablets .  One member of each twin pair took vitamin C and the other took a well matched placebo each day for 100 days . Vitamin C had no significant effect except for shortening the average duration of cold episodes by 19 % Three hundred eleven employees of the National Institutes of Health volunteered to take 1 gm of ascorbic acid or lactose placebo in capsules three times a day for nine months . At the onset of a cold , the volunteers were given an additional 3 gm daily of either a placebo or ascorbic acid .  One hundred ninety volunteers completed the study . Dropouts were defined as those who missed at least one month of drug ingestion . They represented 44 % of the placebo group and 34 % of those taking ascorbic acid . Analysis of these data showed that ascorbic acid had at best only a minor influence on the duration and severity of colds , and that the effects demonstrated might be explained equally well by a break in the double blind During 7 weeks in the spring of 1973 a double-blind pilot study on 172 children in the age group 8 - 9 was carried out to test the possible effect of 1000 mg vitamin C daily as a prophylactic agent against common colds . During the autumn of 1973 , a main study was carried out on 642 children of the same age . The investigations had the same pattern and lasted for 3 months . Both studies have been processed on the same principles . The results were somewhat divergent but , like previously published studies on children , seemed to indicate that the duration and severity of the cold were reduced while , on the other h and , the incidence remained unaltered or indeed increased . The total number of days of upper respiratory tract infection was smaller for the vitamin C group only in the pilot study ( not in the main study ) . No proven biochemical effects were obtained . Preventive treatment of healthy children with vitamin C in large doses this had no definitely proved effect against colds METHOD A large number of women living in two towns in South Wales , and their husb and s , were asked to cooperate in the trial . These women had been identified several years previously in a study of child growth and nutrition and had already cooperated in a prophylactic trial of vitamin C ( Elwood et al. , 1975 ) . The subjects were visited in September and October and those who agreed were given ten effervescent tablets of either vitamin C ( 1 G ) or an inert ; placebo . Allocation of households to vitamin C or placebo was r and om , but each husb and received the same tablets as his wife . This was done to avoid confusion if tablets were shared . The smoking habit of each subject was recorded . Instructions were given that , when symptoms suggestive of a cold commenced , the tablets were to be started , three tablets per day until the 10 tablets had been taken . Symptoms were to be recorded each day for the duration of the cold . Sufficient detail was requested to enable colds to be classed as ‘ simple ’ , that is nasal symptoms with or without general symptoms such as fever or malaise but without any symptom referable to the chest such as cough . ‘ Chest ’ colds were recorded as any symptom-complex which included cough , wheezing , or other chest symptoms . A stamped addressed envelope was given to each subject for the return of the record card . An arbitrary date was chosen approximately six months after the trial commenced , and any subject who had not returned a A concentration of 15 pig/ml was arbitrarily taken as a level read.ly obtainable in h blood wiLh bo.h antibiotics . Th19 strains resistant to penicillin and tetracycline only were resis : ant to  tetracycline  in concentrations above 20 Ag/lml . This resis ance pattern occurs quite frequently in strains of S. aph . aureus isolated both from hospital patients and from the general comnnunity . It would appear therefore that any microbiological advantage which minocycline may exert over other tetracyclines is due to its sup rior activity against strains of Staph . aureus which are resistant to tetracycline . ' -I am , etc . , ARTHUR A. B. MITCHELL Bacteriology Department , Law Hospital , Carluke , Three different dosages of vitamin C , dependent on body weight , were administered to 44 school-aged monozygotic twins for five months using a double-blind , co-twin control study design . The mothers recorded daily observations of cold symptoms , and multiple biochemical , anthropometric , and psychological measurements were made at the beginning and end of the study . Paired comparisons showed no significant overall treatment effect on cold symptoms , but the response was not uniform in all sub-groups . Treated girls in the youngest two groups had significantly shorter and less severe illness episodes , and an effect on severity was also observed in the youngest group of boys . The seven treated twins in the latter group also grew an average of 1.3 cm more than their untreated co-twins during the five-minth period of the study A r and omized controlled trial of the effect of 1 g ascorbic acid per day in the prevention of the common cold was conducted on 688 adult women . There is evidence of a small reduction by  vitamin C  in the mean number of chest colds , but no evidence of any effect on simple colds . The existence of a subgroup of vulnerable women in the community who benefit from vitamin C was considered but further examination of the data gives no support to this conclusion A prospect i ve , r and omized , double-blind study was carried out to determine whether vitamin C prophylaxis , 2.0 g/day , vs placebo prophylaxis would reduce the incidence or morbidity of the common cold  and other respiratory illnesses in 674 marine recruits during an eight-week period . Whole-blood ascorbic acid levels measured six weeks after initiation of the study were significantly higher in the vitamin C group . There was no difference between the two groups in the incidence or duration of colds . The vitamin C group rated their colds as being less severe , but this was not reflected in different symptom complexes or in fewer sick-call visits or training days lost . This study and the literature do not support the prophylactic use of vitamin C to prevent the common cold OBJECTIVE To determine the effect of large doses of vitamin C in the treatment of the common cold . STUDY DESIGN Double-blind , r and omised clinical trial with four intervention arms : vitamin C at daily doses of 0.03 g ( " placebo " ) , 1 g , 3 g , or 3 g with additives ( " Bio-C " ) taken at onset of a cold and for the following two days . PARTICIPANTS AND SETTING 400 healthy volunteers were recruited from staff and students of the Australian National University , Canberra , ACT , between May 1998 and November 1999 . The trial continued for 18 months . INTERVENTIONS Participants were instructed to commence medication when they had experienced early symptoms of a cold for four hours , and to record daily their symptoms , severity , doctor visits and use of other medications . MAIN OUTCOME MEASURES Duration of symptoms and cold episodes ; cumulative symptom severity scores after 7 , 14 and 28 days ; doctor visits ; and whether participants guessed which medication they were taking . RESULTS 149 participants returned records for 184 cold episodes . No significant differences were observed in any measure of cold duration or severity between the four medication groups . Although differences were not significant , the placebo group had the shortest duration of nasal , systemic and overall symptoms , and the lowest mean severity score at 14 days , and the second lowest at 7 and 28 days . CONCLUSIONS Doses of vitamin C in excess of 1 g daily taken shortly after onset of a cold did not reduce the duration or severity of cold symptoms in healthy adult volunteers when compared with a vitamin C dose less than the minimum recommended daily intake A controlled study was made of the effects of natural orange juice , synthetic orange juice , and placebo in the prevention of the common cold ; both natural and synthetic orange juices contained 80 mg of ascorbic acid daily . Three-hundred sixty-two healthy normal young adult volunteers , ages 17 to 25 years , were studied for 72 days with 97 % of participants completing the trial . There was a 14 to 21 % reduction in total symptoms due to the common cold in the supplemented groups that was statistically significant ( P less than 0.05 ) . Ascorbic acid supplementation also increased the number of " episode-free " subjects . However , the clinical usefulness of the results does not support prophylactic ascorbic acid supplements in the well-nourished adult . The results in this study with both natural and synthetic orange juice of physiological content of ascorbic acid , are similar to those obtained using a " megadose " of ascorbic acid This study determined whether daily supplementation with 600 mg vitamin C would reduce the incidence of symptoms of  upper-respiratory-tract ( URT ) infections after participation in a competitive ultramarathon race ( > 42 km ) . Ultramarathon runners with age-matched controls were r and omly divided into placebo and experimental ( vitamin C-supplemented ) groups . Symptoms of URT infections were monitored for 14 d after the race . Sixty-eight percent of the runners in the placebo group reported the development of symptoms of URT infection after the race ; this was significantly more ( P < 0.01 ) than that reported by the vitamin C-supplemented group ( 33 % ) . The duration and severity of symptoms of URT infections reported in the vitamin C-supplemented nonrunning control group was also significantly less than in the nonrunning control group receiving the placebo ( P < 0.05 ) . This study provides evidence that vitamin C supplementation may enhance resistance to the postrace URT infections that occur commonly in competitive ultramarathon runners and may reduce the severity of such infections in those who are sedentary In a survey of double-bind design , 3 groups of approximately 70 student volunteers took 1 g L-ascorbic acid , 1 g D-isoascorbic acid , or placebo tablets every day for 15 weeks and the incidence and duration of colds were recorded . The group taking D-isoascrobic acid suffered 34 % fewer colds than the other two groups ; the results were also analyzed in relation to the sex and smoking habits of the volunteers . The rationale for investigating D-isoascorbic acid , an isomer of L-ascorbic acid which has limited antiscorbutic activity , is discussed Ascorbic acid is widely used as a prophylactic and therapeutic agent against the common cold , and is in fact often recommended for this purpose by medical practitioners . It may be administered as a large dose as soon as possible after the first symptoms are felt , and this dosage is then continued for a few days in order to " abort " the cold . Though many people use this treatment on themselves and believe it is effective , it is impossible to assess its efficacy . Untreated subjects may experience symptoms such as sneezing or a mild sore throat , which then disappear without going on to a full cold , and patients ' assessment s of their colds are much influenced by any treatment owing to the placebo effect ( Diehl et a/. , 1938 ) . In these studies we attempted to show by in-vitro experiments that exposure of cells to ascorbic acid increased their resistance to infection with viruses . Though there was no activity in vitro , we also attempted to demonstrate a protective effect in ftnmy»1 « or man , since it was thought that host resistance might be enhanced indirectly Self-reported cold data have been analyzed for 95 pairs of identical twins aged 14 - 64 who took part in a double-blind trial of vitamin C tablets .  One member of each twin pair took a tablet containing 1 g vitamin C and the other took a well-matched placebo each day for 100 days . In the total sample there was no effect of vitamin C in preventing colds . However , subdivision of the data showed a significant preventive effect of the placebo in the 51 pairs living together and an equal and opposite preventive effect of the vitamin C in the 44 pairs living apart . The placebo effect in the pairs living together may be attributed to the large proportion who wrongly perceived which treatment they were taking . The reduction of colds in the vitamin C group of the pairs living apart was about 20 % . There were significant correlations between cold symptoms reported and the personality trait of neuroticism . No side effects of substantive changes in serum biochemistry could be attributed to the vitamin C dose Abstract A double-blind study to evaluate vitamin C supplements for  respiratory-Infection prophylaxis  was conducted among 641 children at a Navajo boarding school over a 14-week period . Supplements The combination of a regular daily supplement of vitamin C with extra dosage at the time of illness has been shown to reduce the disability due to common colds and other winter illness , but we have seen little effect on frequency of infections , sense of ( well-being ) , or levels of serum cholesterol . The variable results that have been obtained from some other trials of vitamin C may be due in part to variation in the initial nutritional state of the subjects , with the greatest effects to be expected where there is most room for improvement . Because of the great variation in individual susceptibility to infection large numbers of subjects are required in these trials and they must be strictly double-blind . Although we have seen no clear evidence of harmful side-effects , occasional sensitivity to large doses of vitamin C can not be ruled out , and the withdrawal depression of blood levels could conceivably interfere with a patient 's ability to h and le stress A r and omised double-blind trial involving vitamin C/placebo supplementation was conducted on 57 elderly patients admitted to hospital with acute respiratory infections ( bronchitis and bronchopneumonia ) . Patients were assessed clinical ly and biochemically on admission and again at 2 and 4 weeks after admission having received either 20 
    Output:
    