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: OBJECTIVE To study the effect of L-thyroxine supplementation on neurologic maturation in very preterm infants with transient hypothyroxinemia . DESIGN R and omized , double-blind , placebo-controlled , L-thyroxine supplementation trial . SETTING Level III neonatal intensive care unit . SUBJECTS A total of 200 infants < 30 weeks ' gestational age . INTERVENTION Subjects were r and omly assigned to receive L-thyroxine ( 8 microg/kg birth weight per day ) or a placebo during the first 6 weeks of life . METHODS Median nerve somatosensory evoked potentials were recorded , measuring cortical N1 peak latency at 2 weeks of age , at term , and at 6 months ( corrected ) age . RESULTS Cortical N1 peak latency was not decreased significantly in the L-thyroxine group compared with the placebo group throughout the study period . CONCLUSION L-Thyroxine supplementation during the first 6 weeks of life did not decrease cortical N1 peak latency in infants of < 30 weeks ' gestational age It is not known how immaturity and disease influence postnatal thyroid function in infants < 30 wk of gestational age . We performed serial measurements of  plasma thyroxine ( T4 ) , free T4 ( FT4 ) , triiodothyronine ( T3 ) , reverse T3 ( rT3 ) , TSH , and T4-binding globulin ( TBG ) in 100 infants of < 30 wk of gestation , during the first 8 postnatal weeks , to investigate the influences of disease and gestational age on the time course of thyroid hormones . One hundred infants were divided twice into two groups : 1 ) in a group of 25 - 28 and of 28 - 30 wk of gestation ; and 2 ) in a sick and a healthy group , with similar gestational ages . The time course of T4 , FT4 , T3 , TSH , and TBG , but not rT3 differed significantly ( p < 0.005 ) between the gestational age groups . T4 and FT4 decreased to levels below the cord blood value with a deeper FT4 nadir on d 7 in the youngest group . Disease decreased T4 , FT4 , T3 , TSH , and TBG concentrations especially during the 1st wk after birth ( p < 0.005 ) . However , the FT4 nadir on d 7 was similar in sick and healthy infants . After 3 wk , T4 , FT4 , T3 , and TBG were higher in the sick group compared with the healthy group . rT3 levels were not increased in sick infants . We conclude that the extent of the FT4 decrease after birth in infants of < 30 wk gestation is mainly influenced by gestational age and probably reflects a transient depletion of thyroidal hormone reserves . rT3 can not be used as a marker of nonthyroidal illness in very preterm infants OBJECTIVES To supply normative data for screening thyroxine ( T4 ) and thyrotropin concentrations correlated with birth weight and age at screening of infants with birth weights ranging from 400 to 5500 gm , and to document the effects of screening of very low birth weight ( VLBW ) infants , because VLBW infants comprise 0.86 % of surviving newborn infants and have very low total T4 concentrations with normal or elevated free T4 concentrations as a result of deficient protein binding of thyroid hormones . STUDY DESIGN Both retrospective and prospect i ve studies were used . We conducted retrospective analyses of screening of T4 and thyrotropin concentrations in 9,324 term , 18,946 low birth weight , and 3,450 VLBW infants in Massachusetts , and a prospect i ve study of T4 and thyrotropin concentrations in 48 VLBW infants at 2 weeks of age . Forty of the infants also had hormone measurements at 4 weeks , 29 at 8 weeks of age , and 24 had analysis of cord blood sample s. RESULTS Median T4 concentrations for each weight group ( in 250 gm increments ) increased progressively and significantly up to 2500 gm . Of the surviving VLBW infants , 1.5 % had screening T4 concentrations that were unmeasurably low ( < 3.9 nmol/L ( 0.3 microgram/dl ) ) . The mean T4 concentration varied with age at screening , increasing from cord blood concentrations to a peak at 1 to 3 days of age and thereafter decreasing to a nadir at about 2 weeks in both low birth weight and VLBW infants . In VLBW infants the mean concentrations return to the level of 1 to 3 days by 4 to 8 weeks of age . The incidence of screening thyrotropin concentrations > or = 40 mU/L correlates inversely with weight . The incidence of early , transient hypothyroidism in VLBW infants defined by this thyrotropin concentration was eight times that in term infants . Two infants had late-onset , transient hypothyroidism at 2 and 7 weeks , respectively . CONCLUSIONS The normative data related to birth weight and age at screening allow proper interpretation of VLBW results for primary T4 and primary thyrotropin screening programs . Screening of the concentrations of T4 and thyrotropin in VLBW increases the number of secondary measurements of T4 in a primary thyrotropin screening program and the number of secondary thyrotropin measurements in a primary T4 screening program by 6 % and 9 % , respectively . We recommend screening analyses for VLBW infants in the latter part of the first week of life and again at 2 and 4 to 6 weeks of age . This protocol would increase the number of screening analyses by 1.6 % A r and omized , placebo-controlled , masked study was conducted of the responses of thyroid parameters , cortisol , and the cardiovascular system to a single dose of triiodothyronine ( T3 ) 24 h after birth , followed by a daily dose of thyroxine ( T4 ) during 6 wk to infants < 28 wk gestational age . Thirty-one infants were assigned to three groups:1 ) group A : T3 24 h after birth plus daily T4 during 6 wk ; 2 ) group B : placebo T3 and T4 during 6 wk ; and 3 ) group C : placebo T3 and placebo T4  . T4 , free T4 , T3 , free T3 , reverse T3 , thyroid-stimulating hormone , and cortisol were measured in cord blood and on days 1 , 3 , 7 , 14 , 21 , 42 , and 56 . Data on pulse rate , blood pressure , and cumulative dose of inotropic agents were collected . T3 ( 0.5 μg/kg ) result ed in a plasma increase until day 3 . Thereafter , plasma T3 levels were comparable between the groups . T4 , free T4 , and reverse T3 were increased in groups A and B during the period of T4 administration . Thyroid-stimulating hormone suppression was of shorter duration in group A. T3 and T4 administration did not have any effect on cortisol levels . We did not find any effects of T3 or of T4 administration on the cardiovascular system . A single injection of T3 ( 0.5 μg/kg ) given 22–26 h after birth only leads to a 2-d increase of T3 levels and does not have effects on the cardiovascular system . This study does not support the use of T3 according to our regimen in preterm infants OBJECTIVE To compare the effects of therapy with thyroxine ( T4 ) plus triiodothyronine ( T3 ) versus T4 alone from the first days of life in screened congenital hypothyroid ( CH ) infants . METHODS We examined 14 CH infants diagnosed by neonatal screening and a group of control infants . CH patients were divided r and omly into 2 groups , 1 treated with T4 alone ( group 1 ) and the other treated with T4 plus T3 ( liothyronine ; group 2 ) . In all patients  electrocardiography and thyroid hormone evaluations  were performed before and 15 and 30 days and 3 , 6 , and 12 months after the beginning of therapy . Psychological tests were also performed at 6 and 12 months of age in CH patients and in other matched controls . RESULTS After 15 days of treatment , serum thyrotropin ( TSH ) levels become normal in 5 of 7 cases of group 1 ( median TSH level 10.7 micro U/ml ) and in 1 of 7 cases of group 2 ( median TSH level 72.5 micro U/ml ) . At the same period , serum-free thyroid hormone levels were within the normal range in both groups , but free T4 values were significantly higher in group 1 than in group 2 and in controls . At the subsequent examinations , free T4 values were within the upper normal limit in group 1 , whereas they remained within the normal range in group 2 . No clinical or electrocardiographic signs of heart disease were found in any of the patients . The psychometric quotient in CH infants was significantly lower than in controls , but similar in patients of group 1 and group 2 . CONCLUSIONS The combined treatment with T4 plus T3 seems not to show significant advantages , at least in our experimental conditions , compared with the traditional treatment with T4 alone in early treated CH infants . A further longer and more extensive follow-up is m and atory BACKGROUND We have conducted a r and omized trial with thyroxine ( T4 ) in 200 infants < 30 weeks ' gestation .  T4 treatment was associated with better 5-year outcome in infants < 29 weeks ' gestation , but with worse outcome in infants of 29 weeks . These effects could be related to low , respectively high free thyroxine ( FT4 ) levels METHODS For each infant , the average FT4 of 5 scheduled measurements was calculated between day 3 and day 28 . Infants of the  placebo and the  T4 group separately were divided in 2 groups . The placebo group consisted of a group of infants with average FT4 in the lowest quartile and a group in the upper 75 % . The T4 group consisted of a group of infants with average FT4 in the upper quartile and a group in the lower 75 % . Developmental outcome ( mental/cognitive , motor , and neurologic ) at 2 and 5.7 years was compared between high and low FT4 groups , and then compared separately for the T4 and placebo group . RESULTS In the placebo group , low FT4 was associated with worse outcome on all domains at both time points . After correction for confounding variables , mental and neurologic outcome remained significantly different at 2 years , and motor outcome at 5 years . In the T4 group , high FT4 was not associated with worse outcome , neither at 2 nor at 5 years . CONCLUSIONS In untreated infants , low FT4 values during the first 4 weeks after birth in infants born at < 30 weeks ' gestation are associated with worse neurodevelopmental outcome at 2 and 5 years . In  T4-treated infants , high FT4 is not associated with worse outcome . Other factors than high FT4 concentrations must play a role in the worse outcome of the T4-treated group of 29 weeks ' gestational age BACKGROUND Transient hypothyroxinemia is common in preterm infants and has been associated with neurodevelopmental dysfunction and slow nerve conduction velocity . It is still unknown whether L-thyroxine supplementation is required . During an L-thyroxine supplementation trial , motor nerve conduction velocity was measured to answer the question whether L-thyroxine supplementation improves motor nerve conduction velocity . METHODS Two hundred infants < 30 weeks ' gestational age were enrolled in a r and omized , double-blind , placebo-controlled L-thyroxine supplementation trial . L-Thyroxine ( 8 micrograms/kg birthweight per day ) or a placebo was administered during the first 6 weeks of life . Motor nerve conduction velocity was measured in the ulnar and posterior tibial nerve shortly after birth , at 2 weeks , at 40 weeks , and at 66 weeks postmenstrual age . RESULTS At 2 weeks , the ulnar motor nerve conduction velocity had improved in the L-thyroxine group compared with the placebo group , although the difference was not statistically significant ( difference between means : 0.8 msec ; 95 % CI : -0.13 to 1.80 ; p = 0.06 ) . Later on , no effect of L-thyroxine supplementation on motor nerve conduction velocity was found . CONCLUSION This study shows that in infants < 30 weeks ' gestational age  L-thyroxine supplementation during the first 6 weeks of life does not clearly improve motor nerve conduction velocity BACKGROUND Serum thyroid hormone concentrations decline transiently during critical illness and after surgical procedures . We investigated prospect ively the endocrine and haemodynamic effects of tri-iodothyronine treatment after cardiopulmonary bypass operations in children with congenital cardiac malformations . METHODS We did a r and omised , double-blind , placebo-controlled trial , in which 40 children ( median age 0.6 years ; range 2 days to 10.4 years ) were r and omly assigned placebo ( saline ) or one daily infusion of tri-iodothyronine ( 2 microg/kg bodyweight on day 1 after surgery and 1 microg/kg bodyweight on subsequent postoperative days up to 12 days after surgery . Before and 2 h , 24 h , and 72 h after the first infusion , plasma concentrations of thyroid hormones were measured by RIA , and systolic cardiac function was evaluated by echocardiography . During the postoperative course intensive-care measures were assessed by use of the thera 
    Output:
    
agent
***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: OBJECTIVE To study the effect of L-thyroxine supplementation on neurologic maturation in very preterm infants with transient hypothyroxinemia . DESIGN R and omized , double-blind , placebo-controlled , L-thyroxine supplementation trial . SETTING Level III neonatal intensive care unit . SUBJECTS A total of 200 infants < 30 weeks ' gestational age . INTERVENTION Subjects were r and omly assigned to receive L-thyroxine ( 8 microg/kg birth weight per day ) or a placebo during the first 6 weeks of life . METHODS Median nerve somatosensory evoked potentials were recorded , measuring cortical N1 peak latency at 2 weeks of age , at term , and at 6 months ( corrected ) age . RESULTS Cortical N1 peak latency was not decreased significantly in the L-thyroxine group compared with the placebo group throughout the study period . CONCLUSION L-Thyroxine supplementation during the first 6 weeks of life did not decrease cortical N1 peak latency in infants of < 30 weeks ' gestational age It is not known how immaturity and disease influence postnatal thyroid function in infants < 30 wk of gestational age . We performed serial measurements of  plasma thyroxine ( T4 ) , free T4 ( FT4 ) , triiodothyronine ( T3 ) , reverse T3 ( rT3 ) , TSH , and T4-binding globulin ( TBG ) in 100 infants of < 30 wk of gestation , during the first 8 postnatal weeks , to investigate the influences of disease and gestational age on the time course of thyroid hormones . One hundred infants were divided twice into two groups : 1 ) in a group of 25 - 28 and of 28 - 30 wk of gestation ; and 2 ) in a sick and a healthy group , with similar gestational ages . The time course of T4 , FT4 , T3 , TSH , and TBG , but not rT3 differed significantly ( p < 0.005 ) between the gestational age groups . T4 and FT4 decreased to levels below the cord blood value with a deeper FT4 nadir on d 7 in the youngest group . Disease decreased T4 , FT4 , T3 , TSH , and TBG concentrations especially during the 1st wk after birth ( p < 0.005 ) . However , the FT4 nadir on d 7 was similar in sick and healthy infants . After 3 wk , T4 , FT4 , T3 , and TBG were higher in the sick group compared with the healthy group . rT3 levels were not increased in sick infants . We conclude that the extent of the FT4 decrease after birth in infants of < 30 wk gestation is mainly influenced by gestational age and probably reflects a transient depletion of thyroidal hormone reserves . rT3 can not be used as a marker of nonthyroidal illness in very preterm infants OBJECTIVES To supply normative data for screening thyroxine ( T4 ) and thyrotropin concentrations correlated with birth weight and age at screening of infants with birth weights ranging from 400 to 5500 gm , and to document the effects of screening of very low birth weight ( VLBW ) infants , because VLBW infants comprise 0.86 % of surviving newborn infants and have very low total T4 concentrations with normal or elevated free T4 concentrations as a result of deficient protein binding of thyroid hormones . STUDY DESIGN Both retrospective and prospect i ve studies were used . We conducted retrospective analyses of screening of T4 and thyrotropin concentrations in 9,324 term , 18,946 low birth weight , and 3,450 VLBW infants in Massachusetts , and a prospect i ve study of T4 and thyrotropin concentrations in 48 VLBW infants at 2 weeks of age . Forty of the infants also had hormone measurements at 4 weeks , 29 at 8 weeks of age , and 24 had analysis of cord blood sample s. RESULTS Median T4 concentrations for each weight group ( in 250 gm increments ) increased progressively and significantly up to 2500 gm . Of the surviving VLBW infants , 1.5 % had screening T4 concentrations that were unmeasurably low ( < 3.9 nmol/L ( 0.3 microgram/dl ) ) . The mean T4 concentration varied with age at screening , increasing from cord blood concentrations to a peak at 1 to 3 days of age and thereafter decreasing to a nadir at about 2 weeks in both low birth weight and VLBW infants . In VLBW infants the mean concentrations return to the level of 1 to 3 days by 4 to 8 weeks of age . The incidence of screening thyrotropin concentrations > or = 40 mU/L correlates inversely with weight . The incidence of early , transient hypothyroidism in VLBW infants defined by this thyrotropin concentration was eight times that in term infants . Two infants had late-onset , transient hypothyroidism at 2 and 7 weeks , respectively . CONCLUSIONS The normative data related to birth weight and age at screening allow proper interpretation of VLBW results for primary T4 and primary thyrotropin screening programs . Screening of the concentrations of T4 and thyrotropin in VLBW increases the number of secondary measurements of T4 in a primary thyrotropin screening program and the number of secondary thyrotropin measurements in a primary T4 screening program by 6 % and 9 % , respectively . We recommend screening analyses for VLBW infants in the latter part of the first week of life and again at 2 and 4 to 6 weeks of age . This protocol would increase the number of screening analyses by 1.6 % A r and omized , placebo-controlled , masked study was conducted of the responses of thyroid parameters , cortisol , and the cardiovascular system to a single dose of triiodothyronine ( T3 ) 24 h after birth , followed by a daily dose of thyroxine ( T4 ) during 6 wk to infants < 28 wk gestational age . Thirty-one infants were assigned to three groups:1 ) group A : T3 24 h after birth plus daily T4 during 6 wk ; 2 ) group B : placebo T3 and T4 during 6 wk ; and 3 ) group C : placebo T3 and placebo T4  . T4 , free T4 , T3 , free T3 , reverse T3 , thyroid-stimulating hormone , and cortisol were measured in cord blood and on days 1 , 3 , 7 , 14 , 21 , 42 , and 56 . Data on pulse rate , blood pressure , and cumulative dose of inotropic agents were collected . T3 ( 0.5 μg/kg ) result ed in a plasma increase until day 3 . Thereafter , plasma T3 levels were comparable between the groups . T4 , free T4 , and reverse T3 were increased in groups A and B during the period of T4 administration . Thyroid-stimulating hormone suppression was of shorter duration in group A. T3 and T4 administration did not have any effect on cortisol levels . We did not find any effects of T3 or of T4 administration on the cardiovascular system . A single injection of T3 ( 0.5 μg/kg ) given 22–26 h after birth only leads to a 2-d increase of T3 levels and does not have effects on the cardiovascular system . This study does not support the use of T3 according to our regimen in preterm infants OBJECTIVE To compare the effects of therapy with thyroxine ( T4 ) plus triiodothyronine ( T3 ) versus T4 alone from the first days of life in screened congenital hypothyroid ( CH ) infants . METHODS We examined 14 CH infants diagnosed by neonatal screening and a group of control infants . CH patients were divided r and omly into 2 groups , 1 treated with T4 alone ( group 1 ) and the other treated with T4 plus T3 ( liothyronine ; group 2 ) . In all patients  electrocardiography and thyroid hormone evaluations  were performed before and 15 and 30 days and 3 , 6 , and 12 months after the beginning of therapy . Psychological tests were also performed at 6 and 12 months of age in CH patients and in other matched controls . RESULTS After 15 days of treatment , serum thyrotropin ( TSH ) levels become normal in 5 of 7 cases of group 1 ( median TSH level 10.7 micro U/ml ) and in 1 of 7 cases of group 2 ( median TSH level 72.5 micro U/ml ) . At the same period , serum-free thyroid hormone levels were within the normal range in both groups , but free T4 values were significantly higher in group 1 than in group 2 and in controls . At the subsequent examinations , free T4 values were within the upper normal limit in group 1 , whereas they remained within the normal range in group 2 . No clinical or electrocardiographic signs of heart disease were found in any of the patients . The psychometric quotient in CH infants was significantly lower than in controls , but similar in patients of group 1 and group 2 . CONCLUSIONS The combined treatment with T4 plus T3 seems not to show significant advantages , at least in our experimental conditions , compared with the traditional treatment with T4 alone in early treated CH infants . A further longer and more extensive follow-up is m and atory BACKGROUND We have conducted a r and omized trial with thyroxine ( T4 ) in 200 infants < 30 weeks ' gestation .  T4 treatment was associated with better 5-year outcome in infants < 29 weeks ' gestation , but with worse outcome in infants of 29 weeks . These effects could be related to low , respectively high free thyroxine ( FT4 ) levels METHODS For each infant , the average FT4 of 5 scheduled measurements was calculated between day 3 and day 28 . Infants of the  placebo and the  T4 group separately were divided in 2 groups . The placebo group consisted of a group of infants with average FT4 in the lowest quartile and a group in the upper 75 % . The T4 group consisted of a group of infants with average FT4 in the upper quartile and a group in the lower 75 % . Developmental outcome ( mental/cognitive , motor , and neurologic ) at 2 and 5.7 years was compared between high and low FT4 groups , and then compared separately for the T4 and placebo group . RESULTS In the placebo group , low FT4 was associated with worse outcome on all domains at both time points . After correction for confounding variables , mental and neurologic outcome remained significantly different at 2 years , and motor outcome at 5 years . In the T4 group , high FT4 was not associated with worse outcome , neither at 2 nor at 5 years . CONCLUSIONS In untreated infants , low FT4 values during the first 4 weeks after birth in infants born at < 30 weeks ' gestation are associated with worse neurodevelopmental outcome at 2 and 5 years . In  T4-treated infants , high FT4 is not associated with worse outcome . Other factors than high FT4 concentrations must play a role in the worse outcome of the T4-treated group of 29 weeks ' gestational age BACKGROUND Transient hypothyroxinemia is common in preterm infants and has been associated with neurodevelopmental dysfunction and slow nerve conduction velocity . It is still unknown whether L-thyroxine supplementation is required . During an L-thyroxine supplementation trial , motor nerve conduction velocity was measured to answer the question whether L-thyroxine supplementation improves motor nerve conduction velocity . METHODS Two hundred infants < 30 weeks ' gestational age were enrolled in a r and omized , double-blind , placebo-controlled L-thyroxine supplementation trial . L-Thyroxine ( 8 micrograms/kg birthweight per day ) or a placebo was administered during the first 6 weeks of life . Motor nerve conduction velocity was measured in the ulnar and posterior tibial nerve shortly after birth , at 2 weeks , at 40 weeks , and at 66 weeks postmenstrual age . RESULTS At 2 weeks , the ulnar motor nerve conduction velocity had improved in the L-thyroxine group compared with the placebo group , although the difference was not statistically significant ( difference between means : 0.8 msec ; 95 % CI : -0.13 to 1.80 ; p = 0.06 ) . Later on , no effect of L-thyroxine supplementation on motor nerve conduction velocity was found . CONCLUSION This study shows that in infants < 30 weeks ' gestational age  L-thyroxine supplementation during the first 6 weeks of life does not clearly improve motor nerve conduction velocity BACKGROUND Serum thyroid hormone concentrations decline transiently during critical illness and after surgical procedures . We investigated prospect ively the endocrine and haemodynamic effects of tri-iodothyronine treatment after cardiopulmonary bypass operations in children with congenital cardiac malformations . METHODS We did a r and omised , double-blind , placebo-controlled trial , in which 40 children ( median age 0.6 years ; range 2 days to 10.4 years ) were r and omly assigned placebo ( saline ) or one daily infusion of tri-iodothyronine ( 2 microg/kg bodyweight on day 1 after surgery and 1 microg/kg bodyweight on subsequent postoperative days up to 12 days after surgery . Before and 2 h , 24 h , and 72 h after the first infusion , plasma concentrations of thyroid hormones were measured by RIA , and systolic cardiac function was evaluated by echocardiography . During the postoperative course intensive-care measures were assessed by use of the thera 
    Output:
    