scholarly journals Comparison of Compositions and Metabolic Activities of Fecal Microbiotas in Young Adults and in Antibiotic-Treated and Non-Antibiotic-Treated Elderly Subjects

2004 ◽  
Vol 70 (10) ◽  
pp. 6113-6122 ◽  
Author(s):  
Emma J. Woodmansey ◽  
Marion E. T. McMurdo ◽  
George T. Macfarlane ◽  
Sandra Macfarlane
Keyword(s):  
Young Adults ◽  
Species Diversity ◽  
Bifidobacterium Longum ◽  
The Elderly ◽  
Elderly Subjects ◽  
Bifidobacterium Adolescentis ◽  
Healthy Elderly ◽  
Molecular Events ◽  
Metabolic Activities ◽  
Clostridial Species

ABSTRACT The colonic microbiota mediates many cellular and molecular events in the host that are important to health. These processes can be affected in the elderly, because in some individuals, the composition and metabolic activities of the microbiota change with age. Detailed characterizations of the major groups of fecal bacteria in healthy young adults, in healthy elderly people, and in hospitalized elderly patients receiving antibiotics were made in this study, together with measurements of their metabolic activities, by analysis of fecal organic acid and ammonia concentrations. The results showed that total anaerobe numbers remained relatively constant in old people; however, individual bacterial genera changed markedly with age. Reductions in numbers of bacteroides and bifidobacteria in both elderly groups were accompanied by reduced species diversity. Bifidobacterial populations in particular showed marked variations in the dominant species, with Bifidobacterium angulatum and Bifidobacterium adolescentis being frequently isolated from the elderly and Bifidobacterium longum, Bifidobacterium catenulatum, Bifidobacterium boum, and Bifidobacterium infantis being detected only from the healthy young volunteers. Reductions in amylolytic activities of bacterial isolates in healthy elderly subjects and reduced short-chain fatty acid concentrations supported these findings, since bifidobacteria and bacteroides are important saccharolytic groups in the colon. Conversely, higher numbers of proteolytic bacteria were observed with feces samples from the antibiotic-treated elderly group, which were also associated with increased proteolytic species diversity (fusobacteria, clostridia, and propionibacteria). Other differences in the intestinal ecosystem in elderly subjects were observed, with alterations in the dominant clostridial species in combination with greater numbers of facultative anaerobes.

scholarly journals Protein requirements and ageing: metabolic demand and efficiency of utilization

1997 ◽  
Vol 77 (5) ◽  
pp. 685-702 ◽  
Author(s):  
A. Fereday ◽  
N. R. Gibson ◽  
M. Cox ◽  
P. J. Pacy ◽  
D. J. Millward
Keyword(s):  
Young Adults ◽  
The Elderly ◽  
The Body ◽  
Elderly Subjects ◽  
Metabolic Demand ◽  
Protein Requirement ◽  
Body Protein ◽  
Protein Requirements ◽  
Leucine Oxidation ◽  
Healthy Elderly

The protein requirements of the elderly were investigated with [13C]leucine balance studies of metabolic demand, the efficiency of postprandial protein utilization (PPU) and the consequent apparent protein requirement. Ten elderly subjects aged 68–91 years (five men and five women) and ten young adult subjects aged 21–31 years (five men and five women) were infused with L-[1-13C]leucine for 9h commencing in the postabsorptive state (0–3h), continuing during the half-hourly feeding of low-protein meals (LP; protein 3% energy, 3–6 h), and during similar feeding of isoenergetic higher protein meals (HP; protein 15% energy, 6–9h). Leucine oxidation and balance were determined from plasma [l-13C]-α-ketoisocaproate enrichment and expired 13CO2 excretion measured during the 3rd hour of each 3h period. The protein intake during the HP phase was similar to the habitual intake estimated in the subjects from 24h urinary N excretion. Metabolic demand was defined as equal to twice the body-protein equivalent of measured postabsorptive leucine oxidation. The efficiency of PPU was calculated from the increased leucine oxidation observed during feeding, and the apparent protein requirement was defined as metabolic demand/PPU and calculated in relation to both body weight (BW) and fat-free mass (FFM) determined by densitometry or bioimpedance. Metabolic demand in the young adults was 0·83g protein/kg per d; in both elderly groups it was 36% lower when expressed per kg BW and 30% lower when expressed per kg FFM. The apparent protein requirement calculated from metabolic demand and PPU was 0·99g protein/kg per d in the young adults and this was also lower in the elderly, although this was only significant in the men (0·66g per kg BW, P=0·013; 0·79g per kg FFM, P=0·02). The results show that in this group of healthy elderly adults protein requirements as assessed from leucine balance studies were either similar to or less than those of younger adults.

Walking with Visual Restrictions in Healthy Elderly and Young Adults

2002 ◽  
Vol 21 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Sean Gallagher ◽  
Yves Lajoie ◽  
Michel Guay
Keyword(s):  
Young Adults ◽  
Visual Information ◽  
Older Persons ◽  
Visual Cues ◽  
Elderly Population ◽  
The Elderly ◽  
Elderly Subjects ◽  
Elderly Persons ◽  
Experimental Conditions ◽  
Healthy Elderly

ABSTRACTVisual requirements for a simple walking task were evaluated for young and elderly persons to determine if, with normal aging, elderly subjects require more visual information. Ten young adults and 10 elderly people were asked to complete a simple walking task within predetermined pathway boundaries under two conditions of visual restriction. In the reactive condition, subjects automatically received a 200 ms flash of visual information at the halfway point of the walkway. For the predictive condition, subjects did not receive any visual information during the walking trial, but were equipped with an emergency button that would provide 200 ms of visual information whenever they needed it. For both experimental conditions, subjects received additional flashes of visual information if they stepped out of the walkway boundaries. Results showed that older persons stepped out of bounds more often in the reactive condition and gave themselves more visual cues than the younger subjects in the predictive condition. The relative importance of vision during locomotion seems to be higher in the elderly population when compared to young adults.

scholarly journals Pharmacokinetics of Total and Unbound Ertapenem in Healthy Elderly Subjects

2004 ◽  
Vol 48 (2) ◽  
pp. 521-524 ◽  
Author(s):  
D. G. Musson ◽  
A. Majumdar ◽  
S. Holland ◽  
K. Birk ◽  
L. Xi ◽  
...  
Keyword(s):  
Young Adults ◽  
High Performance ◽  
The Elderly ◽  
Reversed Phase ◽  
Elderly Subjects ◽  
Multiple Dosing ◽  
Time Curve ◽  
Unbound Fraction ◽  
Healthy Elderly ◽  
The Mean

ABSTRACT Ertapenem is a new once-a-day parenteral carbapenem antimicrobial agent. The pharmacokinetics of unbound and total concentrations of ertapenem in plasma were investigated in elderly subjects and compared with historical data from young adults. In a single- and multiple-dose study, healthy elderly males and females (n = 14) 65 years old or older were given a 1-g intravenous (i.v.) dose once daily for 7 days. Plasma and urine samples collected for 24 h on days 1 and 7 following administration of the 1-g doses were analyzed by reversed-phase high-performance liquid chromatography. Areas under the concentration-time curve from 0 h to infinity (AUC0-∞) for elderly females and males were similar following administration of 1-g single i.v. doses, and thus, the genders were pooled in subsequent analyses. Concentrations in plasma and the half-life of ertapenem were generally higher and longer, respectively, in elderly subjects than in young adults. The mean AUC0-∞ of total ertapenem in the elderly was 39% higher than that in young subjects following administration of a 1-g dose. The differences were slightly greater for the mean AUC0-∞ of unbound ertapenem (71%). The unbound fraction of ertapenem in elderly subjects (∼5 to 11%) was generally greater than that in young adults (∼5 to 8%). As in young adults, ertapenem did not accumulate upon multiple dosing in the elderly. The pharmacokinetics of ertapenem in elderly subjects, while slightly different from those in young adults, do not require a dosage adjustment for elderly patients.

The influence of dynamic visual environments on postural sway in the elderly

1999 ◽  
Vol 9 (3) ◽  
pp. 197-205
Author(s):  
L.L. Borger ◽  
S.L. Whitney ◽  
M.S. Redfern ◽  
J.M. Furman
Keyword(s):  
Visual Information ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Age Groups ◽  
The Elderly ◽  
Visual Scene ◽  
Elderly Subjects ◽  
Mean Velocity ◽  
Healthy Elderly ◽  
Young Subjects

Postural sway during stance has been found to be sensitive to moving visual scenes in young adults, children, and those with vestibular disease. The effect of visual environments on balance in elderly individuals is relatively unknown. The purpose of this study was to compare postural sway responses of healthy elderly to those of young subjects when both groups were exposed to a moving visual scene. Peak to peak, root mean squared, and mean velocity of the center of pressure were analyzed under conditions combining four moving scene amplitudes ( 2 . 5 ∘ , 5 ∘ , 7 . 5 ∘ , 10 ∘ ) and two frequencies of scene movement (0.1 Hz, 0.25 Hz). Each visual condition was tested with a fixed floor and sway referenced platform. Results showed that elderly subjects swayed more than younger subjects when experiencing a moving visual scene under all conditions. The elderly were affected more than the young by sway referencing the platform. The differences between the two age groups were greater at increased amplitudes of scene movement. These results suggest that elderly are more influenced by dynamic visual information for balance than the young, particularly when cues from the ankles are altered.

Fat and carbohydrate metabolism during exercise in elderly and young subjects

1996 ◽  
Vol 271 (6) ◽  
pp. E983-E989 ◽  
Author(s):  
S. Sial ◽  
A. R. Coggan ◽  
R. Carroll ◽  
J. Goodwin ◽  
S. Klein
Keyword(s):  
Young Adults ◽  
Carbohydrate Metabolism ◽  
Relative Intensity ◽  
The Elderly ◽  
Absolute Intensity ◽  
Substrate Oxidation ◽  
Carbohydrate Oxidation ◽  
Moderate Intensity ◽  
Elderly Subjects ◽  
Moderate Intensity Exercise

We evaluated the effect of aging on fat and carbohydrate metabolism during moderate intensity exercise. Glycerol, free fatty acid (FFA), and glucose rate of appearance (Ra) in plasma and substrate oxidation were determined during 60 min of cycle ergometer exercise in six elderly (73 +/- 2 yr) and six young adults (26 +/- 2 yr) matched by gender and lean body mass. The elderly group was studied during exercise performed at 56 +/- 3% of maximum oxygen uptake, whereas the young adults were studied during exercise performed at the same absolute and at a similar relative intensity as the elderly subjects. Mean fat oxidation during exercise was 25-35% lower in the elderly subjects than in the young adults exercising at either the same absolute or similar relative intensities (P < 0.05). Mean carbohydrate oxidation in the elderly group was 35% higher than the young adults exercising at the same absolute intensity (P < 0.001) but 40% lower than the young adults exercising at the same relative intensity (P < 0.001). Average FFA Ra in the elderly subjects was 85% higher than in the young adults exercising at the same absolute intensity (P < 0.05) but 35% lower than the young adults exercising at a similar relative intensity (P < 0.05). We conclude that fat oxidation is decreased while carbohydrate oxidation is increased during moderate intensity exercise in elderly men and women. The shift in substrate oxidation was caused by age-related changes in skeletal muscle respiratory capacity because lipolytic rates and FFA availability were not rate limiting in the older subjects.

scholarly journals Energy Requirement Equations in Elderly Patients: A Systematic Review (P01-002-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Dario Gregori ◽  
Honoria Ocagli ◽  
Corrado Lanera ◽  
Giulia Lorenzoni
Keyword(s):  
Systematic Review ◽  
Elderly Patients ◽  
Indirect Calorimetry ◽  
Gold Standard ◽  
Web Application ◽  
The Elderly ◽  
Energy Requirements ◽  
Elderly Subjects ◽  
Predictive Equation ◽  
Healthy Elderly

Abstract Objectives Elderly patients are at risk of malnutrition and need an appropriate assessment of energy requirements. In the clinical setting, predictive equations are widely used to estimate the Resting Energy Expenditure (REE). Although easy to use, these equations are not always validated for the elderly and, even if validated, they often provide different outputs of energy requirements for the same subject. This study aimed at doing a systematic review of the equations for the estimation of REE in the elderly with the final aim of developing a web-based application helping clinicians in finding out the most appropriate equation for estimating the REE for each subject. Methods The systematic review was carried out using PubMed and Scopus following PRISMA guidelines. Studies in subjects older than 65 years of age, testing the performance of a predictive equation for the estimation of REE vs. a gold standard (indirect calorimetry or doubly labeled water) were included in the review. Studies performed in critically ill elderly patients were excluded. Results The initial search identified 2035 studies. The final review included 50 studies. Included studies were mainly observational, conducted in healthy elderly subjects enrolled in the outpatient setting, and using indirect calorimetry as gold standard. The 50 studies included in the review corresponded to 189 different equations. Several parameters were included in the equations and they can be divided as following: anthropometric characteristics, body composition parameters, environmental measures, laboratory tests, presence of comorbidities, and physical activity frequency. Conclusions The assessment of the energy requirements in the elderly is crucial for the management of nutritional problems in this population group since nutritional problems are related to worse health outcomes. The present study showed a wide use of different type of equations for the estimation of REE in the elderly highlighting the need of choosing the most appropriate predictive equation according to the subject characteristics and health status. The web application that is currently under development will help clinicians in doing that. Funding Sources Unit of Biostatistics, Epidemiology and Public Health, University of Padova, Padova, Italy.

Effect of ‘Autonomic Blockade’ on Cardiac β-Adrenergic Chronotropic Responsiveness in Healthy Young, Healthy Elderly and Endurance-Trained Elderly Subjects

1994 ◽  
Vol 87 (3) ◽  
pp. 297-302 ◽  
Author(s):  
G. A. Ford ◽  
O. F. W. James
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Geometric Mean ◽  
Cardiovascular Responses ◽  
The Elderly ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Autonomic Blockade ◽  
Young Subjects

1. Cardiac chronotropic responses to isoprenaline are reduced with ageing in man. It is unclear whether this is due to reduced cardiac β-adrenergic sensitivity or to age-associated differences in reflex cardiovascular responses to the vasodilatory effects of isoprenaline. Age-associated changes in physical activity are also reported to influence β-adrenergic sensitivity. 2. The aim of the present study was to determine the contribution of alterations in reflex changes in parasympathetic and sympathetic influences and physical fitness to the age-associated reduction in cardiac chronotropic responses to β-adrenergic agonists. 3. The effect of ‘autonomic blockade’ with atropine (40 μg/kg intravenously) and clonidine (4 μg/kg intravenously) on blood pressure, heart rate and chronotropic responses to intravenous bolus isoprenaline doses was determined in eight healthy young (mean age 21 years), nine healthy elderly (72 years) and 10 endurance-trained elderly (69 years) subjects. 4. Elderly subjects had a reduced increase in heart rate after atropine (young, 49 ± 9 beats/min; elderly, 36 ± 5 beats/min; endurance-trained elderly, 34 ± 12 beats/min; P < 0.01) and did not demonstrate the transient increase in systolic blood pressure after clonidine observed in young subjects (young, 11 ± 10 mmHg; elderly, −12 ± 16 mmHg; endurance-trained elderly, −18 ± 11 mmHg; P < 0.01). 5. Cardiac chronotropic sensitivity to isoprenaline after ‘autonomic blockade’ increased in the young but decreased in the elderly subjects. The isoprenaline dose that increased heart rate by 25 beats/min before and after autonomic blockade' was: young, before 1.6 μg, after 2.8 μg, P < 0.01 (geometric mean, paired test); elderly, before 6.9 μg, after 3.6 μg, P < 0.05; endurance-trained elderly, before 5.9 μg, after 4.0 μg, P < 0.05. Cardiac chronotropic sensitivity to isoprenaline was significantly reduced in elderly compared with young subjects before (P < 0.01) but was similar after (P = 0.09) ‘autonomic blockade’. Chronotropic sensitivity did not differ between healthy and endurance-trained elderly subjects before or after ‘autonomic blockade’. 6. The age-associated reduction in cardiac chronotropic responses to bolus isoprenaline is primarily due to an age-related reduction in the influence of reflex cardiovascular responses on heart rate and not to an age-related reduction in cardiac β-adrenergic sensitivity. Endurance training is not associated with altered β-adrenergic chronotropic sensitivity in the elderly. The transient pressor response to intravenously administered clonidine may be lost in ageing man.

scholarly journals Arginine behaviour after arginine or citrulline administration in older subjects

2015 ◽  
Vol 115 (3) ◽  
pp. 399-404 ◽  
Author(s):  
C. Moinard ◽  
J. Maccario ◽  
S. Walrand ◽  
V. Lasserre ◽  
J. Marc ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
The Elderly ◽  
Volume Of Distribution ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Loading Tests ◽  
Kinetics Of ◽  
Healthy Elderly Subjects

AbstractArginine (ARG) and its precursor citrulline (CIT) are popular dietary supplements, especially for the elderly. However, age-related reductions in lean body mass and alterations in organ functions could change their bioavailability. Pharmacokinetics and tolerance to amino acid (AA) loads are poorly documented in elderly subjects. The objective here was to characterise the plasma kinetics of CIT and ARG in a single-dosing study design. Eight fasting elderly men underwent two separate isomolar oral loading tests (10 g of CIT or 9·94 g of ARG). Blood was withdrawn over an 8-h period to measure plasma AA concentrations. Only CIT, ornithine and ARG plasma concentrations were changed. Volume of distribution was not dependent on AA administered. Conversely, parameters related to ARG kinetics were strongly dependent on AA administered: after ARG load, elimination was higher (ARG>CIT; P=0·041) and admission period+time at peak concentration was lower (ARG<CIT; P=0·033), and the combination of both phenomena results in a marked increase in ARG availability when CIT was administered (ARG<CIT; P=0·033) compared with ARG administration itself. In conclusion, a single CIT administration in the elderly is safe and well tolerated, and CIT proves to be a better in vivo ARG precursor than ARG itself in healthy elderly subjects.

Health Locus of Control and Self-Efficacy Beliefs in a Healthy Elderly Sample

1992 ◽  
Vol 6 (4) ◽  
pp. 302-309 ◽  
Author(s):  
Kathy V. Waller ◽  
R. Carson Bates
Keyword(s):  
Locus Of Control ◽  
Self Efficacy ◽  
Health Locus Of Control ◽  
Good Health ◽  
The Elderly ◽  
Efficacy Beliefs ◽  
Elderly Subjects ◽  
Control Belief ◽  
Lifestyle Behaviors ◽  
Healthy Elderly

Background. The elderly are the fastest growing segment of the population, and this will place additional burdens on the healthcare system. It is therefore valuable to study the elderly who have reached their later years relatively free of disease and in good health. Methods. Health locus of control, self-efficacy beliefs, and lifestyle behaviors were studied in a sample of 57 healthy elderly subjects. Subjects completed the Multidimensional Health Locus of Control Scale, Self-Efficacy Scale, and Healthstyle Self- Test for Seniors. Results. Most of the subjects were characterized by an internal health locus of control belief (91.2%), high generalized self-efficacy (57.9%), and good health behaviors. As hypothesized, positive relationships were found among these variables. Discussion. Individuals with an internal health locus of control and high generalized self-efficacy are more likely to benefit from a health education program than those with an external locus of control and low self-efficacy. Health educators can better serve their clients by evaluating these parameters when developing programs.

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