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: BACKGROUND Plasma threonine concentrations are elevated in infants fed formula containing a whey-to-casein protein ratio of 60:40 compared with concentrations in infants fed formula containing a ratio of 20:80 or human milk ( 60:40 ) . OBJECTIVE We studied whether degradation of excess threonine was lower in formula-fed infants than in infants fed their mothers ' milk . DESIGN Threonine kinetics were examined in 17 preterm infants ( gestational age : 31+/-2 wk : birth weight : 1720+/-330 g ) by using an 18-h oral infusion of [1 - 13C]threonine at a postnatal age of 21+/-11 d and weight of 1971+/-270 g. Five infants received breast milk . Formula-fed infants ( n = 12 ) were r and omly assigned to receive 1 of 3 formulas ( 5.3 g protein/MJ ) that differed only in the whey-to-casein ratio ( 20:80 , 40:60 , and 60:40 ) . RESULTS Threonine intake increased significantly in formula-fed infants with increasing whey content of the formula ( 48.5 , 56.4 , and 63.2 micromol.kg(-1).h(-1 ) , respectively ; pooled SD : 2.2 ; P = 0.0001 ) , as did plasma threonine concentrations ( 228 , 344 , and 419 micromol/L , respectively ; pooled SD : 75 ; P = 0.03 ) . Despite a generous threonine intake by infants fed breast milk ( 58.0+/-16.0 micromol.kg(-1).h(-1 ) , plasma threonine concentrations remained low ( 208+/-41 micromol/L ) . Fecal threonine excretion and net threonine tissue gain , estimated by nitrogen balance , did not differ significantly among groups . Threonine oxidation did not differ significantly among formula-fed infants but was significantly lower in formula-fed infants fed than in infants fed breast milk ( 17.1 % compared with 24.3 % of threonine intake , respectively ) . CONCLUSION Formula-fed infants have a lower capacity to oxidize threonine than do infants fed breast milk BACKGROUND We recently discovered that infants r and omly assigned to a formula high in free amino acids ( extensive protein hydrolysate formula ; ePHF )  during infancy consumed less formula to satiation and gained less weight than did infants fed an isocaloric formula low in free amino acids ( cow milk formula ; CMF ) . OBJECTIVE Because ePHF and CMF differ markedly in concentrations of free glutamate , we tested the hypothesis that the higher glutamate concentrations in ePHF promote satiation and satiety . DESIGN In this counterbalanced , within-subject study , infants < 4 mo of age ( n = 30 ) visited our laboratory for 3 sets of 2 consecutive infant-led formula meals over 3 test days . Infants were fed 1 of 3 isocaloric formulas during each first meal : CMF , ePHF , or CMF with added free glutamate to approximate concentrations in ePHF ( CMF+glu ) . When infants signaled hunger again , they were fed a second meal of CMF . From these data , we calculated satiety ratios for each of the 3 formulas by dividing the intermeal interval by the amount of formula consumed during that particular first meal . RESULTS Infants consumed significantly less  CMF+glu  ( P < 0.02 ) and  ePHF  ( P < 0.04 ) than CMF during the first meals . They also showed greater levels of satiety after consuming CMF+glu  or ePHF : satiety ratios for CMF+glu ( P < 0.03 ) and ePHF ( P < 0.05 ) were significantly higher than for CMF . CONCLUSION These findings suggest a role of free glutamate in infant intake regulation and call into question the cl aim that formula feeding impairs infants ' abilities to self regulate energy intake OBJECTIVE This study was design ed to determine whether marginal dietary protein intakes of lactating women alter their milk production and composition . The study followed the observation that marginal dietary protein intakes lead to significantly negative nitrogen balances in these women . METHODS Twenty-four healthy , mature lactating women were divided evenly into three groups on the basis of postpartum times ; 1 , 5 , or 12 months . Each woman was given a controlled protein diet of either 1.5 ( HP ) or 1.0 ( MP ) g/kg body weight/day for 7 to 10 days . Milk production was measured for 72 hours by test weighing the infant before and after feeding . Milk sample s from alternate breasts were collected for 24 hours , pooled , and analyzed for their protein nitrogen , nonprotein nitrogen , free and protein-bound amino acid , and lactoferrin concentrations . RESULTS Reduced dietary protein intakes were associated with a decrease ( p < 0.05 ) in the nonprotein nitrogen and total free amino acid fractions of milk . Although urea was unaffected , the concentrations of milk free leucine , phenylalanine , histidine , and ornithine were lower ( p < 0.05 ) in the MP than in the HP group , while the output of leucine and histidine tended to be lower in the MP group . The amount of milk produced , as well as the amounts of protein nitrogen , protein-bound amino acid , and lactoferrin and their concentrations were unaffected by a reduction of dietary protein . CONCLUSIONS Maternal milk production and the protein nitrogen , but not the nonprotein nitrogen , fraction of human milk were relatively well-preserved in the presence of a short-term , marginal reduction of dietary protein The optimal quantity and quality of protein for low-birth-weight infants is undefined . In this study , 106 well , appropriate-for-gestational-age , low-birth-weight infants weighing 2,100 gm or less were divided into three gestational age groups and assigned r and omly within each age group to one of five feeding regimens : pooled human milk ; formula 1 ( protein content , 1.5 gm/100 ml- 60 parts bovine whey proteins to 40 parts bovine caseins ) ; formula 2 ( 3.0 gm/100 ml , 60:40 ) ; formula 3 ( 1.5 gm/100 ml , 18:82 ) ; and formula 4 ( 3.0 gm/100 ml , 18:82 ) . The concentrations of the free amino aicds in the plasma and urine of these infants were determined . The plasma concentrations of free amino acids were generally far greater in the infants fed the 3.0-gm/100 ml protein diets than they were in the infants fed pooled human milk . The plasma concentrations of free amino acids of the infants fed the 1.5-gm/100 ml protein diets were intermediate . In general , the concentrations of the free amino acids in the plasma of the infants fed the 3.0-gm/100 ml casein-predominant formula ( F4 ) were furthest from those fed pooled human milk . Glutamate showed the highest plasma amino acid concentrations in infants fed the 3.0-gm/100 ml casein-predominant formula ( F4 ) were furthest from those fed pooled human milk . Glutamate showed the highest plasma amino acid concentrations in infants fed both the high- and low-protein casein-predominant formulas . This was true despite the fact that the intake of glutamate on the high-protein , whey-predominant formula was twice that on the low-protein , casein-predominant formula . The differences between groups in the essential amino acids in plasma were generally greater than those of the nonessential amino acids . The concentrations of amino acids in the urine tended to parallel those of the plasma 
    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: BACKGROUND Plasma threonine concentrations are elevated in infants fed formula containing a whey-to-casein protein ratio of 60:40 compared with concentrations in infants fed formula containing a ratio of 20:80 or human milk ( 60:40 ) . OBJECTIVE We studied whether degradation of excess threonine was lower in formula-fed infants than in infants fed their mothers ' milk . DESIGN Threonine kinetics were examined in 17 preterm infants ( gestational age : 31+/-2 wk : birth weight : 1720+/-330 g ) by using an 18-h oral infusion of [1 - 13C]threonine at a postnatal age of 21+/-11 d and weight of 1971+/-270 g. Five infants received breast milk . Formula-fed infants ( n = 12 ) were r and omly assigned to receive 1 of 3 formulas ( 5.3 g protein/MJ ) that differed only in the whey-to-casein ratio ( 20:80 , 40:60 , and 60:40 ) . RESULTS Threonine intake increased significantly in formula-fed infants with increasing whey content of the formula ( 48.5 , 56.4 , and 63.2 micromol.kg(-1).h(-1 ) , respectively ; pooled SD : 2.2 ; P = 0.0001 ) , as did plasma threonine concentrations ( 228 , 344 , and 419 micromol/L , respectively ; pooled SD : 75 ; P = 0.03 ) . Despite a generous threonine intake by infants fed breast milk ( 58.0+/-16.0 micromol.kg(-1).h(-1 ) , plasma threonine concentrations remained low ( 208+/-41 micromol/L ) . Fecal threonine excretion and net threonine tissue gain , estimated by nitrogen balance , did not differ significantly among groups . Threonine oxidation did not differ significantly among formula-fed infants but was significantly lower in formula-fed infants fed than in infants fed breast milk ( 17.1 % compared with 24.3 % of threonine intake , respectively ) . CONCLUSION Formula-fed infants have a lower capacity to oxidize threonine than do infants fed breast milk BACKGROUND We recently discovered that infants r and omly assigned to a formula high in free amino acids ( extensive protein hydrolysate formula ; ePHF )  during infancy consumed less formula to satiation and gained less weight than did infants fed an isocaloric formula low in free amino acids ( cow milk formula ; CMF ) . OBJECTIVE Because ePHF and CMF differ markedly in concentrations of free glutamate , we tested the hypothesis that the higher glutamate concentrations in ePHF promote satiation and satiety . DESIGN In this counterbalanced , within-subject study , infants < 4 mo of age ( n = 30 ) visited our laboratory for 3 sets of 2 consecutive infant-led formula meals over 3 test days . Infants were fed 1 of 3 isocaloric formulas during each first meal : CMF , ePHF , or CMF with added free glutamate to approximate concentrations in ePHF ( CMF+glu ) . When infants signaled hunger again , they were fed a second meal of CMF . From these data , we calculated satiety ratios for each of the 3 formulas by dividing the intermeal interval by the amount of formula consumed during that particular first meal . RESULTS Infants consumed significantly less  CMF+glu  ( P < 0.02 ) and  ePHF  ( P < 0.04 ) than CMF during the first meals . They also showed greater levels of satiety after consuming CMF+glu  or ePHF : satiety ratios for CMF+glu ( P < 0.03 ) and ePHF ( P < 0.05 ) were significantly higher than for CMF . CONCLUSION These findings suggest a role of free glutamate in infant intake regulation and call into question the cl aim that formula feeding impairs infants ' abilities to self regulate energy intake OBJECTIVE This study was design ed to determine whether marginal dietary protein intakes of lactating women alter their milk production and composition . The study followed the observation that marginal dietary protein intakes lead to significantly negative nitrogen balances in these women . METHODS Twenty-four healthy , mature lactating women were divided evenly into three groups on the basis of postpartum times ; 1 , 5 , or 12 months . Each woman was given a controlled protein diet of either 1.5 ( HP ) or 1.0 ( MP ) g/kg body weight/day for 7 to 10 days . Milk production was measured for 72 hours by test weighing the infant before and after feeding . Milk sample s from alternate breasts were collected for 24 hours , pooled , and analyzed for their protein nitrogen , nonprotein nitrogen , free and protein-bound amino acid , and lactoferrin concentrations . RESULTS Reduced dietary protein intakes were associated with a decrease ( p < 0.05 ) in the nonprotein nitrogen and total free amino acid fractions of milk . Although urea was unaffected , the concentrations of milk free leucine , phenylalanine , histidine , and ornithine were lower ( p < 0.05 ) in the MP than in the HP group , while the output of leucine and histidine tended to be lower in the MP group . The amount of milk produced , as well as the amounts of protein nitrogen , protein-bound amino acid , and lactoferrin and their concentrations were unaffected by a reduction of dietary protein . CONCLUSIONS Maternal milk production and the protein nitrogen , but not the nonprotein nitrogen , fraction of human milk were relatively well-preserved in the presence of a short-term , marginal reduction of dietary protein The optimal quantity and quality of protein for low-birth-weight infants is undefined . In this study , 106 well , appropriate-for-gestational-age , low-birth-weight infants weighing 2,100 gm or less were divided into three gestational age groups and assigned r and omly within each age group to one of five feeding regimens : pooled human milk ; formula 1 ( protein content , 1.5 gm/100 ml- 60 parts bovine whey proteins to 40 parts bovine caseins ) ; formula 2 ( 3.0 gm/100 ml , 60:40 ) ; formula 3 ( 1.5 gm/100 ml , 18:82 ) ; and formula 4 ( 3.0 gm/100 ml , 18:82 ) . The concentrations of the free amino aicds in the plasma and urine of these infants were determined . The plasma concentrations of free amino acids were generally far greater in the infants fed the 3.0-gm/100 ml protein diets than they were in the infants fed pooled human milk . The plasma concentrations of free amino acids of the infants fed the 1.5-gm/100 ml protein diets were intermediate . In general , the concentrations of the free amino acids in the plasma of the infants fed the 3.0-gm/100 ml casein-predominant formula ( F4 ) were furthest from those fed pooled human milk . Glutamate showed the highest plasma amino acid concentrations in infants fed the 3.0-gm/100 ml casein-predominant formula ( F4 ) were furthest from those fed pooled human milk . Glutamate showed the highest plasma amino acid concentrations in infants fed both the high- and low-protein casein-predominant formulas . This was true despite the fact that the intake of glutamate on the high-protein , whey-predominant formula was twice that on the low-protein , casein-predominant formula . The differences between groups in the essential amino acids in plasma were generally greater than those of the nonessential amino acids . The concentrations of amino acids in the urine tended to parallel those of the plasma 
    Output:
    