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Biomedical subjects

M E Barker

Publications and source records attributed to M E Barker.

At least 19 recordsLinked to original sources
PubMed2000

Evaluation of the Dinamap 8100 and Omron M1 blood pressure monitors for use in children.

The aim of this study was to evaluate the Dinamap 8100 and the Omron M1 (the test devices) against standard criteria for use in children in a fieldwork setting. Device calibration and validation were carried out in accordance with the British Hypertension Society protocol for special groups such as children. A total of 102 children, recruited from infant and junior schools in Southampton, had six sequential measurements made of their blood pressure-four measurements with a mercury sphygmomanometer and two with one of two test devices, 55 children with the Dinamap 8100 and 47 with the Omron M1. Systolic and diastolic readings with the Dinamap 8100 were on average 11 mmHg higher (95% confidence interval [CI] +9, +12 mmHg) and 3 mmHg lower (95% CI -5, -1 mmHg), respectively, than measurements with the mercury sphygmomanometer, overestimating systolic pressures and underestimating diastolic pressures across the whole range observed. The Omron M1 gave readings lower by 1 mmHg on average for systolic pressures and 2 mmHg for diastolic pressures compared with the sphygmomanometer (95% CIs -4, +1 mmHg and -5, +1 mmHg respectively), specifically overestimating higher pressures and underestimating lower pressures. According to the criteria of the British Hypertension Society, neither the Dinamap 8100 nor the Omron M1 can be recommended for use in children in clinical situations in which accuracy of the absolute measurement is required. In epidemiological surveys, in which differences in blood pressure between groups of people are more important than absolute levels, it may be more appropriate to use these devices. Of the two, its more consistent performance supports the Dinamap 8100 as the instrument of choice in such studies of children.

Blood Pressure Determination↗
PubMed2000

Growth in utero and blood pressure levels in the next generation.

OBJECTIVE: To determine whether blood pressure levels in adult life are related to the mother's fetal growth and size at birth. DESIGN: A follow-up study of men and women whose mothers' or fathers' size at birth was recorded in Preston, Lancashire, UK. SUBJECTS: Two hundred and twenty-eight men and women born in Preston, Lancashire, UK, and still living in Lancashire. MAIN OUTCOME MEASURES: Blood pressure at 18-40 years of age. RESULTS: Systolic and diastolic pressures fell with increasing mother's birthweight and head circumference. Systolic pressure fell by 2.4 mmHg (95% confidence interval (CI) 0.1-4.7) for each pound increase in mother's birthweight and by 4.0 mmHg (95% CI 0.2-7.8) for each one inch increase in head circumference. These associations were little changed by adjusting for length of gestation or for the subject's age, sex, body mass index or alcohol consumption. They were independent of the mother's blood pressure. As expected, mothers' birthweights were strongly related to their children's birthweights (P= 0.009), but the association between mother's birthweight and offspring's blood pressure was largely independent of this. Father's size at birth was not related to the offspring's blood pressure. CONCLUSIONS: If the growth of a female fetus is constrained by lack of nutrients, there are persisting changes in her physiology and metabolism which lead to reduced fetal growth and raised blood pressure in the next generation. Public health policies to improve fetal growth in one generation may therefore benefit succeeding generations as well.

Adolescent↗
PubMed1999

Zinc supplementation and bone growth in pubertal girls.

We supplemented the diets of 47 peripubertal girls with zinc (15 mg/day) or placebo for 6 weeks. Zinc supplementation increased serum zinc. Insulin-like growth factor I and biochemical markers of bone turnover did not change, albeit dietary zinc was below the reference level (in 94% of individuals).

Adolescent↗
PubMed1999

How are consumers of low-fat and high-fat diets perceived by those with lower and higher fat intake?

Dietary social stereotypes may hinder dietary change. The aim of this study was to measure stereotypes attributed to consumers of low-fat and high-fat diets, and to investigate if stereotype attribution differed with subjects' fat intake. A sample of 100 subjects completed a 24-h dietary recall for the estimation of macronutrient intake, and then completed a questionnaire which assessed the stereotypes associated with a low-fat and a high-fat diet. The low-fat diet was associated with a "healthy", "slim", "fit" and "sporty" person, who was "intelligent", "middle class" and "female". Conversely, the high-fat diet was associated with an "unhealthy", "overweight", "unfit" and "inactive" person, who was "unintelligent", "working class", "smoking" and "male". Followers of the low-fat diet were seen as "serious" and "highly strung", while followers of the high-fat diet were seen as "fun-loving" and "happy". However, positive stereotypes were the predominant descriptors of consumers of the low-fat diet, while negative stereotypes were the predominant descriptors of consumers of the high-fat diet by both men and women. Older people were more likely to choose negative descriptors for a follower of the low-fat diet. Subjects were grouped according to their own fat intake. A high-fat (>33% fat energy) group selected more positive and negative stereotypes to describe high- and low-fat diet consumers, respectively, than did their low-fat counterparts (<33% fat energy). Choice of "happy" to describe a follower of a high-fat diet had four-fold higher odds for the high-fat group. The social meaning and values associated with food choices require further investigation. Health education may need to redress some of these stereotypes.

Adolescent↗
PubMed1998

Attitudes towards meat-eating in vegetarian and non-vegetarian teenage girls in England--an ethnographic approach.

This study compared vegetarian and non-vegetarian teenage English girls' attitudes towards meat. A convenience sample of 15 vegetarian (mean age 17.2 years) and 15 non-vegetarian (mean age 17.3 years) girls was recruited from a teenage health clinic. Attitudes towards meat were assessed in a single, tape-recorded, semi-structured interview. Eight themes of the cultural meaning of meat were identified; five were common to both groups: Animal (66% of vegetarians, 33% of non-vegetarians); Taste/Texture/Smell (66%, 60%); Flesh and Blood (86%, 26%); Colour (33%, 20%); Miscellaneous (60%, 46%). The theme Eating Well was unique to the non-vegetarian group (40%). The themes Life/Death and Health-related were unique to the vegetarian group (66 and 20%, respectively). The vegetarians generally abhorred killing animals for food, meat's sensory characteristics and ingesting blood. A meat-free diet was not particularly associated with health in either group. The non-vegetarians tended to characterize meat positively, both liking meat's sensory characteristics and associating meat with luxury and special occasions. We speculate on possible reasons for the current popularity of vegetarianism in teenage girls.

Adolescent↗
PubMed1998

A longitudinal study of bone gain in pubertal girls: anthropometric and biochemical correlates.

The aim of this longitudinal study was to investigate the factors associated with bone mineral acquisition in pubertal girls. Subjects were 37 healthy, Caucasian girls aged 12.1 years (SD 0.3). Measurements were made at 6-month intervals over a period of 18 months and included total body bone mineral content (TBBMC), total body bone mineral density (TBBMD), lean mass, and fat mass by dual-energy X-ray absorptiometry, anthropometry, lifestyle factors, four biochemical markers of bone turnover, hormonal status, and fractional calcium absorption. In multiple regression analysis, correlates of relative gain in TBBMC were gain in lean mass (p < 0.001) and estradiol (p = 0.008). For TBBMD, correlates were gain in lean (p < 0.001) and fat mass (p = 0.003), estradiol (p < 0.001), dietary energy intake (p = 0.003), and parathyroid hormone (p = 0.023). Statural growth and gain in bone mass were unrelated; both height velocity and bone turnover peaked approximately 20 months prior to menarche, whereas gain in bone mass peaked at menarche. Bone turnover markers correlated with height velocity (0.40 < r < 0.62), but not with bone gain. Estradiol was independently and negatively associated with all markers of bone turnover (-0.67 < r < -0.80). We conclude that estradiol is an important determinant of bone mineral gain in pubertal girls and is probably responsible for the reduction in bone turnover in late puberty; lean mass was the body composition parameter most closely associated with bone gain; height gain and bone gain are dissociated during the period of rapid growth at puberty; and bone turnover markers are modestly related to height gain, but are not predictive of bone gain.

Anthropometry↗
PubMed1997

Milk intake and bone mineral acquisition in adolescent girls: randomised, controlled intervention trial.

OBJECTIVES: To investigate the effect of milk supplementation on total body bone mineral acquisition in adolescent girls. DESIGN: 18 month, open randomised intervention trial. SUBJECTS: 82 white girls aged 12.2 (SD 0.3) years, recruited from four secondary schools in Sheffield. INTERVENTION: 568 ml (one pint) of whole or reduced fat milk per day for 18 months. MAIN OUTCOME MEASURES: Total body bone mineral content and bone mineral density measured by dual energy x ray absorptiometry. Outcome measures to evaluate mechanism included biochemical markers of bone turnover (osteocalcin, bone alkaline phosphatase, deoxypyridinoline, N-telopeptide of type I collagen), and hormones important to skeletal growth (parathyroid hormone, oestradiol, insulin-like growth factor I). RESULTS: 80 subjects completed the trial. Daily milk intake at baseline averaged 150 ml in both groups. The intervention group consumed, on average, an additional 300 ml a day throughout the trial. Compared with the control group, the intervention group had greater increases of bone mineral density (9.6% v 8.5%, P = 0.017; repeated measures analysis of variance) and bone mineral content (27.0% v 24.1%, P = 0.009). No significant differences in increments in height, weight, lean body mass, and fat mass were observed between the groups. Bone turnover was not affected by milk supplementation. Serum concentrations of insulin-like growth factor I increased in the milk group compared with the control group (35% v 25%, P = 0.02). CONCLUSION: Increased milk consumption significantly enhances bone mineral acquisition in adolescent girls and could favourably modify attainment of peak bone mass.

Adolescent↗
PubMed1996

Do type as eat differently? A comparison of men and women.

Type A behaviour has been associated with coronary heart disease, but little is known about how Type A behaviour relates to diet. As part of a cross-sectional epidemiological study in Northern Ireland, Type A behaviour was assessed using a validated questionnaire and diet assessed using weighed records. Diet was described in terms of nutrient intake, food intake and dietary pattern. The study population comprised 245 men and 306 women aged 16 to 64 years. The relation between Type A behaviour and diet was examined by calculating partial correlation coefficients between A-type score and dietary variables, controlling for age and household socio-economic group. In men Type A score showed a weak but significant association with fat and protein intake, and intake of beef, cheese, yoghurt and chips. In women, Type A score showed a weak positive association with sugar and alcohol intake. In both men and women, Type A score was positively associated with the "convenience" dietary pattern. These relationships are discussed in the context of the dominant food ideology and coronary risk.

Adolescent↗
PubMed1995

Attitudinal dimensions of food choice and nutrient intake.

A diet low in fat and rich in fibre has been recommended to optimize general health and in particular cardiovascular health. Health attitudes to fat and fibre were studied in relation to food and nutrient intake and sociocultural and lifestyle factors amongst the general population of Northern Ireland. The study population comprised 592 adults aged 16-64 years; health attitudes to fat and fibre were assessed by questionnaire (based on a social psychological model, which adjusted for taste and convenience factors). Dietary intake was estimated using the weighed inventory technique. Fat-phobic and fibre-philic attitudes were more prevalent in women than men. Fat-phobic attitudes in women were inversely related to intake of fat through a reduced intake of chips, butter and sausages. In contrast, men's fat-phobic attitudes were not strongly correlated with fat intake; consumption of chips and sausages was negatively associated with fat-phobic attitudes, but cake/biscuit, buns/pastries and milk consumption was positively associated with fat-phobic attitudes. Fibre-philic attitudes were positively associated with dietary fibre intake; intakes of potatoes, vegetables, wholemeal bread and breakfast cereal were positively associated with fibre-philic attitudes. There were clear sociocultural and lifestyle differences in relation to dietary attitude. These findings have implications for campaigns designed to effect population dietary change.

Adolescent↗
PubMed1992

Dietary behaviour and health in Northern Ireland: an exploration of biochemical and haematological associations.

STUDY OBJECTIVE: The aim was to determine the relationships between dietary behaviour and biochemical and haematological measures. DESIGN: This was a cross sectional population study. SETTING: The study took place in the general community within Northern Ireland. SUBJECTS: 522 randomly selected adults aged 18-64 years took part (65% of the eligible sample). MEASUREMENTS AND MAIN RESULTS: Four dietary behaviours were identified using principal components analysis from 7 d weighed dietary records described in terms of mean intake of 41 food groups. Haematological and biochemical analyses were carried out on non-fasting blood samples. Social, personal, and lifestyle information was ascertained through interviewer administered questionnaires. Partial correlations controlled for age and smoking behaviour were calculated. There were significant negative associations between iron status measures and the "traditional" behaviour, while the "meat and two veg" behaviour showed positive associations. There were positive associations between the "cosmopolitan" and "convenience" behaviours and folate status in women. White cell count and platelet levels in women were negatively associated with the "traditional" and "cosmopolitan" behaviours. Total cholesterol levels showed significant negative associations with the "cosmopolitan" behaviour in women and HDL cholesterol levels were positively associated with the "cosmopolitan", "convenience" and "meat and two veg" behaviours. CONCLUSIONS: Through a multivariate approach to dietary assessment it is possible to identify food combinations that cluster and interact to influence biochemical and haematological indices of health status.

Adolescent↗
PubMed1991

Potential contribution of leisure activity to the energy expenditure patterns of sedentary populations.

Total daily energy expenditure (TEE) by the doubly-labelled (2H218O) water method and basal metabolic rate (BMR) by indirect calorimetry were measured in thirty-two healty free-living adults in Northern Ireland. Habitual physical activity patterns in occupational and discretionary activities were assessed by interview questionnaire. Expressed as a multiple of BMR the TEE values for the sixteen males (1.88 (SD 0.28), range 1.44-2.57) and sixteen females (1.77 (SD 0.16), range 1.50-2.06) were compatible with current Department of Health and Social Security (DHSS; 1979) and Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU; 1985) estimates of energy requirements. The results suggest that discretionary physical activity is now emerging as an equally important determinant of energy expenditure in the UK as the occupational classifications currently used as the basis of DHSS (1979) and FAO/WHO/UNU (1985) recommendations for energy requirements. Therefore, realistically achievable inputs of recreational exercise can have a significant impact in counteracting low levels of energy expenditure which are associated with modern lifestyles and are implicated as a risk factor for coronary heart disease and obesity.

Adult↗
PubMed1991

Localization of epidermal growth factor receptor in hepatocyte nuclei.

Experiments undertaken to investigate the binding of epidermal growth factor by hepatocyte nuclei showed that: (a) isolated nuclei from both normal and regenerating rat liver are capable of binding 125I-epidermal growth factor, (b) the nuclear epidermal growth factor-binding protein is similar in molecular weight to the plasma membrane epidermal growth factor receptor, (c) monoclonal antibodies produced against the plasma membrane epidermal growth factor receptor recognize the nuclear epidermal growth factor receptor and (d) the nuclear receptor has an affinity for epidermal growth factor comparable to that of the plasma membrane receptor, but fewer (approximately 10%) nuclear receptors are available per protein unit compared with the plasma membrane.

Animals↗
PubMed1991

Localization of tumor necrosis factor-stimulated DNA synthesis in the liver.

Tumor necrosis factor and other cytokines mediate the body's response to infection and inflammation. Long-term administration of tumor necrosis factor causes liver hypertrophy, and our laboratory has shown that tumor necrosis factor acutely increases hepatic DNA synthesis. The purpose of this study was to determine which specific cell types in the liver undergo DNA synthesis in response to tumor necrosis factor. Light microscopic autoradiographs of 3H-thymidine incorporation demonstrate that tumor necrosis factor stimulates DNA synthesis in nonparenchymal cells, whereas the low level of DNA synthesis normally found in hepatocytes remains unaffected. Tumor necrosis factor increased labeling in sinusoidal cells that appeared to be Kupffer cells and in cells localized to the portal tracts. With electron microscopy and histochemical staining for endogenous peroxidase, the sinusoidal cells were clearly identified as Kupffer cells. The exact identity of the cells in the portal tract is less certain, but some of the cells shared the characteristics of bile duct precursors. With long-term administration of tumor necrosis factor, a striking proliferation of bile ducts was seen. The functional role of the proliferation of bile ducts in response to tumor necrosis factor is unclear, and it is not known whether the increase is a beneficial or deleterious response. The increased DNA synthesis in Kupffer cells could result in a potentially beneficial response to infection by increasing an animal's ability to phagocytize and clear microorganisms. However, under some circumstances, an expansion of the number of Kupffer cells could be deleterious by increasing an animal's ability to produce tumor necrosis factor and other cytokines that in large quantities can have toxic effects.

Animals↗
PubMed1990

Accuracy of weighed dietary records in studies of diet and health.

OBJECTIVE: To provide an independent evaluation of seven day weighed dietary records, which are currently accepted as the most accurate technique for assessing habitual dietary intake in studies investigating the links between diet and health. DESIGN: Subjects who had previously participated in the Northern Ireland diet and health study were reselected by stratified random sampling to represent the range of energy intakes in the study as assessed by the seven day weighed dietary record. SETTING: Northern Ireland. SUBJECTS: 31 Free living adults (16 men and 15 women). MAIN OUTCOME MEASURES: Energy intake as measured by the seven day weighed dietary record and total energy expenditure estimated concurrently by the doubly labelled water technique. RESULTS: Average recorded energy intakes were significantly lower than measured expenditure in the group overall (9.66 MJ/day v 12.15 MJ/day, 95% confidence interval 1.45 to 3.53 MJ/day). Among those in the upper third of energy intakes the mean (SE) ratio of intake to expenditure was close to 1.0, indicating accurate records (men 1.01 (0.11), women 0.96 (0.08]. In the middle and lower thirds the ratios for men were only 0.74 (0.05) and 0.70 (0.07) respectively and for women 0.89 (0.07) and 0.61 (0.07). CONCLUSIONS: These results show a serious bias in reporting habitual energy intake. If substantiated they may have wide implications for the interpretation of many nutritional studies.

Adolescent↗
PubMed1990

Iron sufficiency in the population of Northern Ireland: estimates from blood measurements.

Estimates of iron status in a random sample (218 men, 283 women) of the Northern Ireland population (aged 18-64 years) were obtained from blood measurements. Multiple criteria were used to determine Fe deficiency and body Fe stores were calculated as an index of Fe sufficiency. Three distinct groups with respect to Fe stores were identified on the basis of sex and menstrual status. Estimates of body Fe stores, mean (and SD), were 13.4 (SD 5.97), 5.3 (SD 6.09) and 8.5 (SD 6.72) mM for men, woman aged 18-44 years and women aged 45-64 years respectively. The prevalence of Fe-deficiency anaemia was low, ranging from 0.5% in men to 6.6% and 4.6% in the younger and older women respectively. The prevalence of Fe deficiency was low in men (1.4%) and older women (5.7%) rising to 11.0% in the younger group of women. The disproportionately elevated serum ferritin relative to transferrin saturation supported the suggestion that chronic inflammation might have influenced Fe status measurements in men and older women.

Adolescent↗
PubMed1990

Dietary behaviours and sociocultural demographics in Northern Ireland.

Subjects aged 16-64 years (592; 258 men and 334 women), randomly selected from the population of Northern Ireland, kept a 7 d weighed record of all food and drink consumed. Social, personal and anthropometric data were also collected. From the weighed records food consumption was described in terms of forty-one food groups. Using principal components analysis, four distinct dietary patterns were generated which were identified as a traditional diet, a cosmopolitan diet, a convenience diet and a 'meat and two veg' diet. These dietary patterns were then correlated with sociocultural, lifestyle and anthropometric variables. It is clear that dietary behaviour is influenced by a number of inter-related sociocultural demographics and that identifiable population groups in Northern Ireland have different dietary behaviours.

Adolescent↗