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 Gastric distension reduces food intake , and antral , rather than proximal , gastric distension may be the dominant mechanism in the induction of appetite-related sensations . Healthy aging is associated with reduced appetite . OBJECTIVE We examined the effects of different energy preloads on appetite , plasma cholecystokinin , antral area , and subsequent energy intake in healthy older and young subjects . DESIGN On 3 separate days , 12 young and 12 older subjects consumed 400 mL of a drink containing either 0 kcal ( water ) , 250 kcal , or 750 kcal 70 min before a buffet-style meal . RESULTS Hunger was less in the older than in the young subjects ( P < 0.001 ) . Both nutrient preloads reduced hunger and increased fullness more than did water ( P < 0.02 ) , and older subjects were more full than were the young ( P < 0.05 ) . Antral area was greater after the nutrient preloads than after water ( P = 0.001 ) and greater in the older than in the young subjects ( P = 0.005 ) . In both groups , food intake was suppressed in an energy-dependent manner ( P = 0.008 ) . Plasma cholecystokinin was greater in the older than in the young subjects ( P = 0.003 ) . Immediately before the meal , hunger ( r = -0.59 ) and energy intake ( r = -0.90 ) were inversely related and fullness ( r = 0.66 ) was directly related to antral area ( all : P < 0.001 ) . Antral area , but not plasma cholecystokinin , was a predictor of subsequent energy intake . CONCLUSION In healthy young and older subjects , the suppression of subsequent energy intake by a liquid preload is nutrient dependent and comparable , and both satiation and satiety are related to antral area and ( presumably ) antral distension BACKGROUND Aging is associated with a decrease in appetite and a slowing of gastric emptying . The gastrointestinal hormones cholecystokinin ( CCK ) , glucagon-like peptide 1 ( GLP-1 ) , and peptide YY ( PYY ) may mediate these changes . OBJECTIVE We investigated whether aging influenced the secretion of CCK , GLP-1 , and PYY and their effects on appetite and pyloric motility . DESIGN Eight healthy older ( 65 - 80 y ) and 7 younger ( 20 - 34 y ) men received isoenergetic ( 12.1 kJ/min ) intraduodenal infusions of lipid and glucose for 120 min on separate days . Plasma CCK , GLP-1 , and PYY concentrations were measured . RESULTS Plasma CCK concentrations were higher in older than in younger subjects ( P = 0.004 ) as a result of higher baseline values ( 4.7+/-0.2 compared with 3.2+/-0.2 pmol/L ; P < 0.0001 ) and a greater rise during lipid infusion ( increase from baseline : 7.1+/-0.5 compared with 5.3+/-0.6 pmol/L ; P = 0.048 ) . Plasma GLP-1 and PYY concentrations were not significantly different between groups . The decrease in hunger during intraduodenal lipid infusion was inversely related to the increase in CCK , GLP-1 , and PYY in younger but not older subjects . During intraduodenal lipid infusion , the increase in isolated pyloric pressure wave ( IPPW ) frequency was positively related to GLP-1 and PYY and the increase in IPPW amplitude was positively related to CCK in older but not younger subjects , whereas the increase in IPPW amplitude and pyloric tone was negatively related to GLP-1 and PYY in younger subjects . CONCLUSIONS Human aging is associated with increased CCK concentrations , which may contribute to the slowing of gastric emptying , mediated by increased pyloric motility . The role of increased plasma CCK concentrations in mediating the age-related decrease in appetite remains to be established To assess the biological activity and tolerability of pegylated recombinant native human leptin ( PEG-OB ) , 30 obese men ( mean body mass index , 33.9 kg/m2 ) were r and omized to a double-blind treatment with weekly sc injections of 20 mg PEG-OB or placebo for 12 weeks , in addition to a hypocaloric diet ( deficit , 2 MJ/day ) . Body composition , energy expenditure , and metabolic parameters were measured before and after treatment . PEG-OB was generally well tolerated based on adverse event reports , lab values , and vital signs . Weekly sc PEG-OB led to sustained serum concentrations of PEG-OB and leptin throughout treatment . No significant differences in the delta or percent weight loss , percent body fat , sleeping metabolic rate , or respiratory quotient were observed between the PEG-OB and placebo groups . Percent change in serum triglycerides from baseline was significantly correlated with body weight loss in the PEG-OB group , but not in the placebo group . Although larger reductions in serum triglycerides were observed in the PEG-OB group compared with the placebo group , these differences were not statistically significant . We concluded that weekly injection of PEG-OB leads to sustained serum concentration of PEG-OB and leptin throughout the 12-week treatment period and is generally well tolerated . The trends observed in serum triglycerides suggest that a weekly 20-mg sc treatment with PEG-OB may have biological effects in obese men Healthy aging is associated with reductions in appetite and food intake -- the so-called anorexia of aging , which may predispose to protein-energy malnutrition . One possible cause of the anorexia of aging is an increased satiating effect of cholecystokinin ( CCK ) . To investigate the impact of aging on the satiating effects of CCK , 12 young and 12 older healthy subjects received 25-min iv infusions of saline ( control ) and CCK-8 , 1 ng/kg per min or 3 ng/k per min , on 3 separate days before a test meal . Older subjects ate less than young subjects , and food intake was suppressed 21.6 % by CCK-8 , compared with the control day ( P < 0.05 ) . The suppression of energy intake by CCK-8 in older subjects was twice that in young subjects ( 32 + /- 6 % vs. 16 + /- 6 % SEM , P < 0.05 ) and was related to plasma CCK-8 concentrations , which were higher at baseline ( P < 0.05 ) and increased more during CCK-8 infusions in older than young subjects ( P < 0.01 ) . The extent of suppression of food intake per given rise in plasma CCK-8 concentrations did not differ between the two age groups ( P = 0.35 ) . Endogenous CCK concentrations were higher at baseline in older subjects ( P < 0.001 ) and decreased during the CCK-8 but not control infusions ( P < 0.01 ) , suggesting that CCK suppresses its own release . Plasma leptin concentrations were not affected by CCK infusion , whereas postpr and ial insulin concentrations were lowered and the peak postpr and ial glucose concentration was delayed but not affected by CCK-8 infusion . Because older people retain their sensitivity to the satiating effects of exogenous CCK and plasma endogenous CCK concentrations are higher in older people , increased CCK activity may contribute to the anorexia of aging Protein-rich supplements are used widely for the prevention and management of malnutrition in older people . We have reported that healthy older , compared to younger , adults have less suppression of energy intake by whey-protein — effects on appetite-related hormones are unknown . The objective was to determine the effects of intraduodenally administered whey-protein on glucose , gut hormone , and amino acid concentrations , and their relation to subsequent ad libitum energy intake at a buffet meal , in healthy older and younger men .  Hydrolyzed whey-protein ( 30 kcal , 90 kcal , and 180 kcal ) and a saline control ( ~0 kcal ) were infused intraduodenally for 60 min in 10 younger ( 19–29 years , 73 ± 2 kg , 22 ± 1 kg/m2 ) and 10 older ( 68–81 years , 79 ± 2 kg , 26 ± 1 kg/m2 ) healthy men in a r and omized , double-blind fashion . Plasma insulin , glucagon , gastric inhibitory peptide ( GIP ) , glucagon-like peptide-1 ( GLP-1 ) , peptide tyrosine-tyrosine ( PYY ) , and amino acid concentrations , but not blood glucose , increased , while ghrelin decreased during the whey-protein infusions . Plasma GIP concentrations were greater in older than younger men . Energy intake correlated positively with plasma ghrelin and negatively with insulin , glucagon , GIP , GLP-1 , PYY , and amino acids concentrations ( p < 0.05 ) . In conclusion , intraduodenal whey-protein infusions result ed in increased GIP and comparable ghrelin , insulin , glucagon , GIP , GLP-1 , PYY , and amino acid responses in healthy older and younger men , which correlated to subsequent energy intake Objective : Visual analogue scales are widely used in appetite research , yet the validity of these scales to evaluate appetite and mood has not been assessed in older subjects . The aim of this study was to determine the relations between food intake and visual analogue scale ( VAS ) ratings of appetite and nonappetite sensations in healthy older and young subjects . Design : Retrospective combined analysis of four single-blind , r and omised , controlled appetite studies . Setting : All studies were conducted in the University of Adelaide , Department of Medicine , Adelaide , Australia . Subjects : A total of 45 healthy young men ( n=24 ) and women ( n=21 ) aged 18–35 y and 45 healthy older men ( n=24 ) and women ( n=21 ) aged 65–85 y were recruited by advertisement . Interventions : Oral , intraduodenal or intravenous administration of treatments which suppressed food intake were compared to control . Up to 90 min after treatment , a test meal was offered and subjects ate freely for between 30 and 60 min . Perceptions were assessed by 100-mm visual analogue scales administered at regular intervals . Results : Food intake at the test meal was positively related to perceptions of hunger , drowsiness , and calmness at both baseline and premeal ( r>0.16 , P<0.05 ) , and inversely related to premeal ratings of fullness ( r > 0.2 , P<0.05 ) in both older and young subjects . Food intake was related to VAS ratings at least as strongly , if not more so , in older as in young subjects . Conclusions : These observations ( i ) confirm that food intake is related to perceptions of hunger and fullness as assessed by VAS in healthy older and young subjects , and ( ii ) suggest that sensations , not obviously associated with appetite , including ‘ drowsiness ’ and ‘ calmness ’ , are also associated with food intake 
    Output:
    
agent
Higher circulating concentrations of insulin , leptin , cholecystokinin and peptide-YY accord with reduced appetite and energy intakes in healthy older adults .
Interventions to reduce circulating levels of these hormones may be beneficial for combatting the anorexia of ageing
***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 Gastric distension reduces food intake , and antral , rather than proximal , gastric distension may be the dominant mechanism in the induction of appetite-related sensations . Healthy aging is associated with reduced appetite . OBJECTIVE We examined the effects of different energy preloads on appetite , plasma cholecystokinin , antral area , and subsequent energy intake in healthy older and young subjects . DESIGN On 3 separate days , 12 young and 12 older subjects consumed 400 mL of a drink containing either 0 kcal ( water ) , 250 kcal , or 750 kcal 70 min before a buffet-style meal . RESULTS Hunger was less in the older than in the young subjects ( P < 0.001 ) . Both nutrient preloads reduced hunger and increased fullness more than did water ( P < 0.02 ) , and older subjects were more full than were the young ( P < 0.05 ) . Antral area was greater after the nutrient preloads than after water ( P = 0.001 ) and greater in the older than in the young subjects ( P = 0.005 ) . In both groups , food intake was suppressed in an energy-dependent manner ( P = 0.008 ) . Plasma cholecystokinin was greater in the older than in the young subjects ( P = 0.003 ) . Immediately before the meal , hunger ( r = -0.59 ) and energy intake ( r = -0.90 ) were inversely related and fullness ( r = 0.66 ) was directly related to antral area ( all : P < 0.001 ) . Antral area , but not plasma cholecystokinin , was a predictor of subsequent energy intake . CONCLUSION In healthy young and older subjects , the suppression of subsequent energy intake by a liquid preload is nutrient dependent and comparable , and both satiation and satiety are related to antral area and ( presumably ) antral distension BACKGROUND Aging is associated with a decrease in appetite and a slowing of gastric emptying . The gastrointestinal hormones cholecystokinin ( CCK ) , glucagon-like peptide 1 ( GLP-1 ) , and peptide YY ( PYY ) may mediate these changes . OBJECTIVE We investigated whether aging influenced the secretion of CCK , GLP-1 , and PYY and their effects on appetite and pyloric motility . DESIGN Eight healthy older ( 65 - 80 y ) and 7 younger ( 20 - 34 y ) men received isoenergetic ( 12.1 kJ/min ) intraduodenal infusions of lipid and glucose for 120 min on separate days . Plasma CCK , GLP-1 , and PYY concentrations were measured . RESULTS Plasma CCK concentrations were higher in older than in younger subjects ( P = 0.004 ) as a result of higher baseline values ( 4.7+/-0.2 compared with 3.2+/-0.2 pmol/L ; P < 0.0001 ) and a greater rise during lipid infusion ( increase from baseline : 7.1+/-0.5 compared with 5.3+/-0.6 pmol/L ; P = 0.048 ) . Plasma GLP-1 and PYY concentrations were not significantly different between groups . The decrease in hunger during intraduodenal lipid infusion was inversely related to the increase in CCK , GLP-1 , and PYY in younger but not older subjects . During intraduodenal lipid infusion , the increase in isolated pyloric pressure wave ( IPPW ) frequency was positively related to GLP-1 and PYY and the increase in IPPW amplitude was positively related to CCK in older but not younger subjects , whereas the increase in IPPW amplitude and pyloric tone was negatively related to GLP-1 and PYY in younger subjects . CONCLUSIONS Human aging is associated with increased CCK concentrations , which may contribute to the slowing of gastric emptying , mediated by increased pyloric motility . The role of increased plasma CCK concentrations in mediating the age-related decrease in appetite remains to be established To assess the biological activity and tolerability of pegylated recombinant native human leptin ( PEG-OB ) , 30 obese men ( mean body mass index , 33.9 kg/m2 ) were r and omized to a double-blind treatment with weekly sc injections of 20 mg PEG-OB or placebo for 12 weeks , in addition to a hypocaloric diet ( deficit , 2 MJ/day ) . Body composition , energy expenditure , and metabolic parameters were measured before and after treatment . PEG-OB was generally well tolerated based on adverse event reports , lab values , and vital signs . Weekly sc PEG-OB led to sustained serum concentrations of PEG-OB and leptin throughout treatment . No significant differences in the delta or percent weight loss , percent body fat , sleeping metabolic rate , or respiratory quotient were observed between the PEG-OB and placebo groups . Percent change in serum triglycerides from baseline was significantly correlated with body weight loss in the PEG-OB group , but not in the placebo group . Although larger reductions in serum triglycerides were observed in the PEG-OB group compared with the placebo group , these differences were not statistically significant . We concluded that weekly injection of PEG-OB leads to sustained serum concentration of PEG-OB and leptin throughout the 12-week treatment period and is generally well tolerated . The trends observed in serum triglycerides suggest that a weekly 20-mg sc treatment with PEG-OB may have biological effects in obese men Healthy aging is associated with reductions in appetite and food intake -- the so-called anorexia of aging , which may predispose to protein-energy malnutrition . One possible cause of the anorexia of aging is an increased satiating effect of cholecystokinin ( CCK ) . To investigate the impact of aging on the satiating effects of CCK , 12 young and 12 older healthy subjects received 25-min iv infusions of saline ( control ) and CCK-8 , 1 ng/kg per min or 3 ng/k per min , on 3 separate days before a test meal . Older subjects ate less than young subjects , and food intake was suppressed 21.6 % by CCK-8 , compared with the control day ( P < 0.05 ) . The suppression of energy intake by CCK-8 in older subjects was twice that in young subjects ( 32 + /- 6 % vs. 16 + /- 6 % SEM , P < 0.05 ) and was related to plasma CCK-8 concentrations , which were higher at baseline ( P < 0.05 ) and increased more during CCK-8 infusions in older than young subjects ( P < 0.01 ) . The extent of suppression of food intake per given rise in plasma CCK-8 concentrations did not differ between the two age groups ( P = 0.35 ) . Endogenous CCK concentrations were higher at baseline in older subjects ( P < 0.001 ) and decreased during the CCK-8 but not control infusions ( P < 0.01 ) , suggesting that CCK suppresses its own release . Plasma leptin concentrations were not affected by CCK infusion , whereas postpr and ial insulin concentrations were lowered and the peak postpr and ial glucose concentration was delayed but not affected by CCK-8 infusion . Because older people retain their sensitivity to the satiating effects of exogenous CCK and plasma endogenous CCK concentrations are higher in older people , increased CCK activity may contribute to the anorexia of aging Protein-rich supplements are used widely for the prevention and management of malnutrition in older people . We have reported that healthy older , compared to younger , adults have less suppression of energy intake by whey-protein — effects on appetite-related hormones are unknown . The objective was to determine the effects of intraduodenally administered whey-protein on glucose , gut hormone , and amino acid concentrations , and their relation to subsequent ad libitum energy intake at a buffet meal , in healthy older and younger men .  Hydrolyzed whey-protein ( 30 kcal , 90 kcal , and 180 kcal ) and a saline control ( ~0 kcal ) were infused intraduodenally for 60 min in 10 younger ( 19–29 years , 73 ± 2 kg , 22 ± 1 kg/m2 ) and 10 older ( 68–81 years , 79 ± 2 kg , 26 ± 1 kg/m2 ) healthy men in a r and omized , double-blind fashion . Plasma insulin , glucagon , gastric inhibitory peptide ( GIP ) , glucagon-like peptide-1 ( GLP-1 ) , peptide tyrosine-tyrosine ( PYY ) , and amino acid concentrations , but not blood glucose , increased , while ghrelin decreased during the whey-protein infusions . Plasma GIP concentrations were greater in older than younger men . Energy intake correlated positively with plasma ghrelin and negatively with insulin , glucagon , GIP , GLP-1 , PYY , and amino acids concentrations ( p < 0.05 ) . In conclusion , intraduodenal whey-protein infusions result ed in increased GIP and comparable ghrelin , insulin , glucagon , GIP , GLP-1 , PYY , and amino acid responses in healthy older and younger men , which correlated to subsequent energy intake Objective : Visual analogue scales are widely used in appetite research , yet the validity of these scales to evaluate appetite and mood has not been assessed in older subjects . The aim of this study was to determine the relations between food intake and visual analogue scale ( VAS ) ratings of appetite and nonappetite sensations in healthy older and young subjects . Design : Retrospective combined analysis of four single-blind , r and omised , controlled appetite studies . Setting : All studies were conducted in the University of Adelaide , Department of Medicine , Adelaide , Australia . Subjects : A total of 45 healthy young men ( n=24 ) and women ( n=21 ) aged 18–35 y and 45 healthy older men ( n=24 ) and women ( n=21 ) aged 65–85 y were recruited by advertisement . Interventions : Oral , intraduodenal or intravenous administration of treatments which suppressed food intake were compared to control . Up to 90 min after treatment , a test meal was offered and subjects ate freely for between 30 and 60 min . Perceptions were assessed by 100-mm visual analogue scales administered at regular intervals . Results : Food intake at the test meal was positively related to perceptions of hunger , drowsiness , and calmness at both baseline and premeal ( r>0.16 , P<0.05 ) , and inversely related to premeal ratings of fullness ( r > 0.2 , P<0.05 ) in both older and young subjects . Food intake was related to VAS ratings at least as strongly , if not more so , in older as in young subjects . Conclusions : These observations ( i ) confirm that food intake is related to perceptions of hunger and fullness as assessed by VAS in healthy older and young subjects , and ( ii ) suggest that sensations , not obviously associated with appetite , including ‘ drowsiness ’ and ‘ calmness ’ , are also associated with food intake 
    Output:
    