PubMed Health⌕ Search

Biomedical subjects

M S Lawson

Publications and source records attributed to M S Lawson.

At least 19 recordsLinked to original sources
PubMed2006

Body composition in normal weight, overweight and obese children: matched case-control analyses of total and regional tissue masses, and body composition trends in relation to relative weight.

BACKGROUND: Childhood obesity is defined on the basis of weight and height, using body mass index (BMI). There is little detailed information on the body composition characteristic of overweight and obesity. OBJECTIVE: To evaluate total and regional body composition in overweight, obese and control children aged 7-14 years. DESIGN: Body composition was measured by the four-component model and dual X-ray absorptiometry in 38 age- and sex-matched pairs of obese and control children. Body composition trends were also evaluated by quintile of BMI standard deviation score (SDS) in these and 31 other children (n=107; BMI SDS range -1.0 to 4.3). RESULTS: Obese children were taller than controls (Delta=0.6 SDS; P=0.01) and had greater hydration of fat-free mass (FFM) (Delta=1.8 %, P<0.0001). After adjusting for these variables, obese children had greater FFM, fat mass (FM) and mineral (P<0.0001). Regional analyses showed that these differences were apparent in the arm, leg and trunk, but the three tissues had different proportional distributions of the excess. Fat was primarily in the trunk, but mineral in the leg. FM, FFM, hydration and mineral mass all increased across BMI SDS quintiles (P<0.0001), but the trend for FM was much the steepest. DISCUSSION: The greater weight of obese children is due to excess FFM including mineral as well as excess fatness. Increasing weight has a strong continuous relationship with increasing FM across the whole spectrum of weight.

Absorptiometry, Photon↗
PubMed2005

Composition of the fat-free mass in obese and nonobese children: matched case-control analyses.

OBJECTIVE: Most body composition techniques assume constant properties of the fat-free mass (FFM), such as hydration, density and mineralisation. Previous studies suggested that FFM composition may change in childhood obesity; however, this issue has not been investigated in detail. AIM: To compare FFM composition in obese and nonobese children. DESIGN: Observational matched case-control analyses. SUBJECTS: A total of 28 obese children (13 boys, 15 girls) and 22 nonobese children (10 boys, 12 girls) aged 7-14 y. Obesity was defined as body mass index centile >95. METHODS: Measurements were made of weight, height, total body water, and body volume. Bone mineral content was estimated in a subsample. Body composition was calculated using three- and four-component models. RESULTS: According to the three-component model (n=22 matched pairs), obese children had greater hydration (P<0.05), and reduced density (P=0.057) of FFM. According to the four component model (n=11 pairs), obese children had greater hydration (P<0.01) and reduced density (P<0.002) of FFM. The mineralisation of FFM was increased, but not significantly so. CONCLUSION: The greater hydration and reduced density of FFM of obese children should be taken into account if body composition is to be measured with optimum accuracy during treatment programmes. These differences may be addressed by using multicomponent rather than two-component models of body composition. Although the greater mineralisation of FFM in obese children was not significant in the present study, the four-component model is best able to address the combined differences in hydration and mineralisation that occur in childhood obesity.

Absorptiometry, Photon↗
PubMed2005

Assessing the acceptability and feasibility of the MEND Programme in a small group of obese 7-11-year-old children.

BACKGROUND AND AIMS: An uncontrolled, pilot study to evaluate feasibility and acceptability of a new community based childhood obesity treatment programme. METHODS: The mind, exercise, nutrition and diet (MEND) programme was held at a sports centre, twice-weekly, for 3 months. The programme consists of behaviour modification, physical activity and nutrition education. The primary outcome measure was waist circumference. Secondary outcomes were body mass index (BMI), cardiovascular fitness (heart rate, blood pressure and number of steps in 2 min), self-esteem and body composition. BMI of parents was also measured. See http://www.mendprogramme.org. RESULTS: Eleven obese children (7-11 years) and their families were recruited. Mean attendance was 78% (range 63-88%) with one drop out. Waist circumference, cardiovascular fitness and self-esteem were all significantly improved at 3 months and continued to improve at 6 months. BMI was significantly improved at 3 months but lost significance by 6 months. Deuterium studies showed a beneficial trend but were not significant. Of the 17 parents measured, seven were obese (BMI >/= 30) and eight overweight (BMI >/= 25). CONCLUSIONS: Although limited by the small number of participants and no control group, the MEND programme was acceptable to families and produced significant improvements in a range of risk factors associated with obesity that persisted over 3 months.

Body Mass Index↗
PubMed2004

Number of days needed to assess energy and nutrient intake in infants and young children between 6 months and 2 years of age.

OBJECTIVE: To estimate the minimum number of days of recorded dietary intake needed to place infants and young children into thirds of a population distribution with an acceptable degree of accuracy. DESIGN: Dietary intake data collected from 5-day weighed food records for 72 infants and young children up to 2 y of age, collected during a cross-sectional study, were analysed to estimate the number of recording days necessary to assess intake of energy and 10 nutrients. SETTING: Community study among healthy infants and children. SUBJECTS: Parents attended recruitment sessions in local community areas. In total, 72 subjects were entered into the study and all completed the 5-day dietary assessment period. INTERVENTIONS: A 5-day weighed record of children's dietary intake was made by the parents or regular carer. RESULTS: Mean within subject standard deviations were smaller than mean between subject standard deviations with respect to energy (778 vs 824 kJ/day), macronutrient subclasses: protein (8 vs 9.4 g/day); fat (9 vs 10 g/day); and carbohydrate (26 vs 29 g/day) and for specific micronutrients: calcium (163 vs 236 mg/day); phosphorus (143 vs 270 mg/day); magnesium (25 vs 43 mg/day); iron (2 vs 3 mg/day); zinc (1 vs 1.3 mg/day); ascorbic acid (27 vs 64 mg/day) and retinol equivalents (281 vs 424 microg/day). Estimated number of days of food records necessary to assess intake of energy, protein, fat and carbohydrate with acceptable degree of accuracy were 5,4,4 and 3, respectively. For all the micronutrients included in this analysis 2 days of recording were necessary. CONCLUSION: Compared with adults and older children, fewer days are needed to classify this age group into thirds of the distribution with an acceptable degree of accuracy according to intake of energy and specific nutrients. SPONSORSHIP: The data collection phase of this study was supported by a grant from the Procter and Gamble Company, Cincinnati, OH, USA.

Age Factors↗
PubMed2001

Validation of food diary method for assessment of dietary energy and macronutrient intake in infants and children aged 6-24 months.

OBJECTIVES: To compare the estimated food diary record (ED) method against weighed intake record method (WI) for assessing dietary intake in infants and children aged 6-24 months; additionally, to compare WI with metabolisable energy intake (ME) measured by doubly labelled water (DLW) in infants aged 6 12 months. DESIGN: Cross-over study of 5 day WI vs 5 day ED. SUBJECTS: Seventy-two children aged 6-24 months. METHODS: Subjects were randomly assigned to one method during week 1 crossing over to the alternative method in week 2. Data were coded and translated into daily nutrient intakes using COMP-EAT version 5 nutritional analysis software. The analysis compared energy, protein, fat and carbohydrate. Twenty-one infants were dosed with DLW for measurement of total energy expenditure (TEE) and ME. RESULTS: Mean energy intake calculated from WI and ED was 3,782 and 3,920 kJ/day, respectively. There was no significant difference between these values. Using WI as a reference, ED showed a mean bias of 138 kJ/day, equivalent to 3.6% of mean energy intake. Limits of agreement (+/- 2 s.d. of the bias) were wide at +/- 1,385 kJ/day. There were no significant differences between methods for any of the nutrient sub-classes. Using DLW as a reference, WI showed a mean bias of 243 kJ/day, equivalent to 7.3% of mean energy intake, limits of agreement were wide at +/- 1686 kJ/day. CONCLUSION: There is no evidence from the present analysis that ED is less accurate than WI for assessing energy and nutrient sub-class intakes in groups of this age but this good agreement between methods in groups does not extend to individuals.

Age Factors↗
PubMed1998

Iron status of Asian children aged 2 years living in England.

Haemoglobin and ferritin values were analysed in blood from 1057 children, aged 2 years, of Asian parents living in England. Children who had thalassaemia trait or a current/recent infection were excluded. Twenty nine per cent of Pakistani, 25% of Bangladeshi, and 20% of Indian children had haemoglobin < 110.0 g/l. The recent national diet and nutrition survey of preschool children found a prevalence of 12% of 2 year olds with haemoglobin < 110.0 g/l. No single factor accounted for more than a small proportion of the variance in haemoglobin and ferritin values, but the most significant factors that had a negative effect on iron status included the amount of cows' milk consumed, the use of a baby bottle, and mother's place of birth being outside of the UK. Taking vitamin or iron supplements was positively associated with iron status in one or more of the three groups.

Asia↗
PubMed1994

Potential aluminium toxicity in infants fed special infant formula.

Aluminium was measured in samples of plasma and samples of feed obtained from 74 infants with normal renal function established on various feeds (breast, whey-based, fortified whey-based, preterm, soy, and casein hydrolysate). All infants were bolus fed, and blood samples were collected midway between feeds. Aluminium was measured using electrothermal atomization and atomic absorption spectrometry. Mean aluminium concentrations in milks were as follows: breast, 9.2 micrograms/L [95% confidence interval (CI), 5.6-12.7]; whey-based, 165 micrograms/L (95% CI, 151-180); fortified, 161 micrograms/L (95% CI, 143-180); preterm, 300 micrograms/L (95% CI, 272-328); soy, 534 micrograms/L (95% CI, 470-598); casein hydrolysate, 773 micrograms/L (95% CI, 632-914). Mean plasma aluminium concentrations in infants receiving different milks were as follows: breast, 8.6 micrograms/L (95% CI, 5.6-10.6); whey-based, 9.2 micrograms/L (95% CI, 7.4-11.0); fortified, 10.3 micrograms/L (95% CI, 8.3-12.3); preterm, 9.7 micrograms/L (95% CI, 5.3-17.1); soy, 12.5 micrograms/L (95% CI, 5.0-20.0); casein hydrolysate, 15.2 micrograms/L (95% CI, 10.7-19.8). Mean plasma aluminium concentration was significantly different in infants fed casein hydrolysate formulae than in those fed breast milk (difference, 6.7 micrograms/L; 95% CI, 2.8-10.5; p = 0.028). We conclude that infants may be at risk from aluminium toxicity when consuming formula containing > 300 micrograms/L--in particular, casein hydrolysate formulae. We speculate that the aluminium compounds found in breast milk are more bioavailable than those found in other milks and that some constituents of infant formula affect aluminium absorption from the gut lumen.

Aluminum↗
PubMed1991

Stabilization of [99mTc]HMPAO--1. Ethanolic preparation.

The use of [99mTc]HMPAO for cerebral blood flow imaging has been hampered by the short useful life time of the labelled radiopharmaceutical. Preparation of [99mTc]HMPAO in 85% ethanol was found to increase the in vitro stability (92% radiochemical purity at 90 min) in comparison to the aqueous preparation (79% at 90 min). Biological distribution studies in mice indicated similar brain uptake (4.42 +/- 1.02 and 4.12 +/- 0.82% per gram at 20 min) and brain: blood ratio (0.97 +/- 0.27 and 1.03 +/- 0.20 at 20 min) of the ethanolic (2 h after preparation) and aqueous (15 min after preparation) formulations of [99mTc]HMPAO respectively. The improved in vitro stability of [99mTc]HMPAO prepared in 85% ethanol may prove useful in instances where previously the 30 min time limit precluded its use.

Animals↗
PubMed1989

Chemical aspects of labeling sucralfate with 99mTcO4.

Two formulations of [99mTc]sucralfate have been used to image gastric and duodenal ulcers and inflammatory bowel disease. One formulation is a complexation of [99mTc]HSA with sucralfate. The second is prepared by directly labeling sucralfate with [99mTc]pertechnetate in the presence of stannous ion. An in vitro study of the factors affecting the production and stability of these labeled sucralfate preparations was conducted. Both formulations were stable at the acidic pH likely encountered in the stomach. However, at pH greater than 6 the albumin-sucralfate complex began to dissociate while directly labeled sucralfate was stable to a pH of 9. Conversely it was shown that directly labeled sucralfate was more susceptible to loss of 99mTc to other chelating species. Sucralfate complexed with [99mTc]HSA was radiochemically stable up to a specific activity of 26 GBq (700 mCi) per gram while directly labeled sucralfate showed decreased 24-hr stability at specific activities greater than 837 mCi (31 GBq) per gram.

Chemical Phenomena↗
PubMed1988

Selenium balance studies in apparently healthy and housebound elderly people eating self-selected diets.

1. Metabolic balance studies (5 d) for Se were conducted in twenty-four apparently healthy elderly people (age 69.6-85.4 years), and twenty housebound subjects (age 69.9-85.1 years) with chronic disease. During the study the subjects lived in their own homes, ate self-selected diets and continued their normal daily activities. 2. Geometric mean daily dietary intakes of the two groups were significantly different (P less than 0.01), being 819 (range 310-1631) nmol for the healthy and 475 (range 233-1136) nmol for the housebound elderly. 3. Daily intake of Se significantly correlated with balance in both groups. Solution of the regression equations gave theoretical daily requirements of 447 nmol for the healthy and 419 nmol for the housebound subjects. The healthy elderly were in positive balance of 148 nmol/d for Se and the housebound were in equilibrium with an overall mean retention of 43 nmol/d. 4. Mean levels of Se in blood fractions for the healthy and housebound subjects were significantly different, being 1.65 and 1.40 mumol/l whole blood, 1.45 and 1.21 mumol/l plasma and 5.72 and 5.30 nmol/g haemoglobin in erythrocytes respectively. There was no difference in the whole-blood glutathione peroxidase (EC 1.11.1.9) activities between the two groups. 5. There were clear differences in Se status between the two groups of elderly people. The cause of the positive balance in the healthy subjects remains unexplained.

Aged↗
PubMed1987

Nitrogen balance studies in apparently healthy elderly people and those who are housebound.

Metabolic balance studies (5 d) for nitrogen were carried out in twenty-four apparently healthy elderly people (age 69.7-85.6 years) and a heterogeneous group of twenty housebound elderly people (age 69.9-85.1 years) with chronic diseases. During the study all subjects ate self-selected diets, lived in their own homes and continued their normal daily activities. Seven of the housebound received meals-on-wheels 5 d/week. Healthy men and women had mean metabolizable energy intakes of 8.7 and 6.6 MJ/d respectively compared with 6.3 and 4.8 MJ/d in the housebound. The average energy content of the meals-on-wheels as delivered was 2.4 MJ per meal, of which 2.1 MJ were consumed. The healthy men and women had average daily protein intakes of 69.4 and 59.7 g respectively compared with 46.3 and 39.1 g in the housebound. Meals-on-wheels as supplied provided 19.4 g protein per meal, of which 16.2 g were consumed. Healthy subjects were in equilibrium for N balance (0 mmol/d) with a daily intake of 733 mmol, which was equivalent to 11.04 mmol N (0.97 g mixed protein)/kg body-weight per d. Housebound individuals were in negative N balance (-95 mmol/d) with an intake of 475 mmol/d, corresponding to 7.59 mmol N (0.67 g mixed protein)/kg body-weight per d. We were unable to determine in the present study whether the negative N balance observed in the housebound people was due to the relatively low N intake or the underlying disease condition.

Aged↗
PubMed1987

Metabolic balance studies for zinc and copper in housebound elderly people and the relationship between zinc balance and leukocyte zinc concentrations.

Five-day metabolic balance studies for zinc and copper were carried out in 20 housebound elderly people with stable chronic diseases. Subjects were age 70.0-85.1 y, lived in their own homes, and ate self-selected diets. Mean daily intakes for Zn and Cu were 90 mumol and 13.4 mumol with mean negative balances of -16 and -1.1 mumol, respectively. Both balance values significantly differed from equilibrium (p less than 0.05). For Zn and Cu, respectively, mean concentrations were 11.3 and 22.1 mumol/L plasma, 103 and 19.4 mumol/L whole blood, and 98 and 8.7 pmol/10(6) leukocytes. The results for Zn and Cu balance and leukocyte concentrations were different from those obtained by us for healthy elderly people (Am J Clin Nutr 1984;40: 1096-120). A highly significant (r = 0.75, p less than 0.001) correlation was observed between zinc balance and leukocyte zinc concentrations.

Aged↗
PubMed1984

The uptake and excretion of chromium by the elderly.

Metabolic balance studies for chromium have been carried out on 22 apparently healthy elderly people and one subject with impaired glucose tolerance. All subjects were aged between 69.7 and 85.5 yr, ate self-chosen diets, and lived in their own homes during the study. The mean daily intake of chromium for the healthy subjects was 471 nmol (24.5 micrograms) with a mean retention of 3 nmol (0.2 microgram). The subject with a raised plasma glucose was in positive balance for chromium. Although the daily chromium intake was below the lower limit of the estimated safe and adequate daily dietary intake proposed by the American Food and Nutrition Board it appeared to be adequate for these subjects.

Aged↗
PubMed1984

The intake and excretion of lead and cadmium by the elderly.

Metabolic balance for lead and cadmium were carried out in 23 healthy elderly people aged 69.7 to 85.5 yr while living in their own homes and eating self-selected diets. Mean intakes of lead and cadmium were 54.6 and 8.6 micrograms/day, with mean retentions of -8.7 and -1.7 micrograms/day, respectively. Daily dietary lead correlated (p less than 0.05) with the intake of energy, nitrogen, calcium, iron, and zinc but not with manganese or copper. Dietary intake of cadmium correlated (p less than 0.05) only with that of zinc and manganese. There was a highly significant (p less than 0.001) inverse correlation between the percentage cadmium absorbed and body iron stores measured as serum iron, percentage iron saturation, and ferritin. Mean whole blood concentrations were 138 micrograms/l for lead and 0.79 microgram/l for cadmium. The negative balances observed in these elderly people were very different from the positive balances found in a previous similar study in children.

Absorption↗
PubMed1984

Assessment of zinc and copper status of healthy elderly people using metabolic balance studies and measurement of leucocyte concentrations.

Metabolic balance studies for zinc and copper were carried out in 24 apparently healthy elderly people aged 69.7 to 85.5 yrs, living in their own homes and eating self-selected diets. The zinc and copper concentration in whole blood, plasma, and leucocytes were also measured. Mean daily intakes for zinc and copper were 137 and 20.1 mumol with mean retentions of 1.0 and -0.8 mumol, respectively. These values did not differ significantly from equilibrium (p less than 0.01). For zinc and copper, respectively, mean concentrations were 11.0 and 19.4 mumol/l in plasma, 120 and 11.5 mumol/10(6) cells in leucocytes, and 99 and 13.4 mumol/l in whole blood. These data will provide normal standard values for elderly people in good health and should serve as a basis for the investigation of elderly people with suspected deficiencies of these trace metals.

Absorption↗
PubMed1984

Uptake and excretion of iron by healthy elderly subjects.

Metabolic balance studies for iron have been carried out on 24 apparently healthy elderly people (11 men and 13 women) aged 69.7 to 85.5 years living in their own homes and eating self selected diets. Several biochemical and haematological indices of iron state were also measured. The mean daily iron intake was 176 mumol, with a range of 55-321 mumol. Eight women and six men consumed diets which provided less than the recommended daily dietary allowance for iron of 179 mumol/day. Mean daily retention of iron, however, was -7 mumol, a value which did not significantly differ from equilibrium. No sex difference was noted between any of the biochemical and haematological measurements. Mean values of iron concentration, iron binding capacity, iron binding saturation, and ferritin and haemoglobin concentrations were 20 mumol/l, 59 mumol/l, 34%, 77 micrograms/l, and 14.3 g/dl, respectively. We have shown that in apparently healthy elderly people who are in equilibrium for iron balance, several biochemical and haematological measurements of iron state do not differ from the normal ranges established in younger adults.

Aged↗
PubMed1982

Metabolic balance studies for zinc and nitrogen in healthy elderly subjects.

Metabolic balances for zinc and nitrogen were performed in ten healthy elderly men and women aged 72.2 to 85.4 yr whilst they were living in their own homes. The mean daily retentions of nitrogen and zinc were 29 mmol (range-38 to +179) and 4 micromol (range -17 to +16) respectively. The mean concentrations of zinc were 11.9 micromol/1 plasma (lower than in younger adults) and 89.8 micromol/1 whole blood (similar to that of younger adults). There was no significant correlation between these values nor was there correlation with the overall retention of zinc. The balance data provide reference values against which the findings in malnourished, sick and institutionalized elderly may be better assessed.

Aged↗