PubMed Health⌕ Search

Biomedical subjects

A E Black

Publications and source records attributed to A E Black.

At least 19 recordsLinked to original sources
PubMed2003

An evaluation of the sensitivity and specificity of energy expenditure measured by heart rate and the Goldberg cut-off for energy intake: basal metabolic rate for identifying mis-reporting of energy intake by adults and children: a retrospective analysis.

OBJECTIVE: To identify adults and children as under- (UR), acceptable (AR), or over-reporters (OR) of energy intake (EI) using energy expenditure measured by doubly labelled water (DLW) (EE(DLW)), and to use this as a reference to determine the sensitivity and specificity of (i) EE measured by heart rate (EE(HR)), and (ii) the Goldberg cut-off technique for classifying subjects into the same categories. DESIGN: Retrospective analysis of a dataset comprising concurrent measurements of EE(DLW), EE(HR), basal metabolic rate (BMR), and EI by weighed record (EI(WR)) on 14 adults and 36 children. EI by diet history (EI(DH)) was also measured in the children only. EI(WR):EE(DLW) provided the reference definition of subjects as UR, AR or OR. Three strategies for classifying mis-reporters based on EE(HR) and Goldberg cut-offs were then explored. Sensitivity and specificity were calculated respectively as the proportion of UR and non-UR correctly identified. RESULTS: Approximately 80% of all subjects were AR. For EI(WR) and EI(DH) respectively, the sensitivity of EE(HR) was 0.50 and 1.00, and specificity was 0.98 and 1.00. Although designating subjects as having low, medium or high activity levels (EE(HR):BMR(meas)) and calculating cut-offs based on appropriate WHO physical activity level PALs did not change sensitivity, specificity dropped to 0.98 (EI(WR)) and 0.97 (EI(DH)). Cut-offs based on a PAL of 1.55 reduced sensitivity to 0.33 (EI(WR)) and 0.00 (EI(DH)), but specificity remained unchanged. The sensitivity of all cut-offs based on physical activity level (PALs) for EI(WR) was 0.50 (adults) and 0.25 (children). CONCLUSIONS: If the precision of EE(HR) was improved, it may be useful for identifying mis-reporters of EI.

Adolescent↗
PubMed2001

Biased over- or under-reporting is characteristic of individuals whether over time or by different assessment methods.

Seven studies with repeated measurements of energy intake and/or nitrogen intake were examined to determine whether misreporting is characteristic of some persons or occurs randomly. Four of the studies were validated by doubly labeled water measurements of energy expenditure. Reporting validity was expressed as the ratio of energy intake to energy expenditure. Ratios were consistently below the expected value of 1.0 for some subjects and consistently above 1.0 for others, indicating characteristic reporting validity within subjects. Two year-long studies provided 4 to 12 measurements and a total number of days sufficient to measure individual habitual intake. Subjects mean energy intake to basal metabolic rate (BMR) ratios were < 1.35 in 45% and 47% and < 1.35 at every measurement in 25% of subjects. This indicated persistent underreporting over time, because 1.35 x BMR is the minimum energy expenditure compatible with a normally active lifestyle. Three of the studies used more than 1 assessment method (validated by doubly labeled water and/or urinary nitrogen excretion). There was a tendency for persons determined to be underreporters by 1 method to be also underreporters when tested by other methods. We conclude that biased over- or underreporting is characteristic of some persons. Thus, repeat measurements do not necessarily provide valid measures of individual intake, extreme intakes may reflect under- and overreporting rather than true low or high intakes, and subjects most prone to reporting bias may be repeatedly misclassified in quantiles of the distribution. This presents a challenge to dietitians nutritionists, and statisticians both for the design of surveys and the handling of flawed data.

Adolescent↗
PubMed2001

The genetic basis of plasma variation in adiponectin, a global endophenotype for obesity and the metabolic syndrome.

Here we present the first genetic analysis of adiponectin levels, a newly identified adipocyte-derived protein. Recent work has suggested that adiponectin may play a role in mediating the effects of body weight as a risk factor for coronary artery disease. For this analysis we assayed serum levels of adiponectin in 1100 adults of predominantly northern European ancestry distributed across 170 families. Quantitative genetic analysis of adiponectin levels detected an additive genetic heritability of 46%. The maximum LOD score detected in a genome wide scan for adiponectin levels was 4.06 (P = 7.7 x 10(-6)), 35 cM from pter on chromosome 5. The second largest LOD score (LOD = 3.2; P = 6.2 x 10(-5)) was detected on chromosome 14, 29 cM from pter. The detection of a significant linkage with a quantitative trait locus on chromosome 5 provides strong evidence for a replication of a previously reported quantitative trait locus for obesity-related phenotypes. In addition, several secondary signals offer potential evidence of replications for additional previously reported obesity-related quantitative trait loci on chromosomes 2 and 10. Not only do these results identify quantitative trait loci with significant effects on a newly described, and potentially very important, adipocyte-derived protein, they also reveal the emergence of a consistent pattern of linkage results for obesity-related traits across a number of human populations.

Adiponectin↗
PubMed2000

Intensity of bacteraemia associated with conservative dental procedures in children.

OBJECTIVES: To explore the individual dento-gingival manipulative procedures that together lead to the placement of a restoration and to estimate the associated intensity of bacteraemia. PATIENTS AND METHODS: Healthy children receiving dental treatment under general anaesthesia provided blood samples 30 seconds after one of four dento-gingival manipulative procedures: 1. Placement of rubber dam, 2. Use of the high speed drill, 3. Use of the slow speed drill, and 4. Placement of matrix band and wedge. Blood cultures were processed to give the percentage prevalence of bacteraemia, the intensity of organisms per millilitre of blood and the identity of the organisms cultured. RESULTS: A total of 257 children were recruited to the study. The percentage positive prevalence of blood cultures was baseline--9.3%, rubber dam placement--31.4%, slow drill--12.2%, fast drill--4.3%, and matrix band and wedge--32.1%. The intensity of bacteraemia was baseline--1.2 cfu, rubber dam placement--1,962 cfu, slow drill--0.3 cfu, fast drill--1.9 cfu, matrix band and wedge--4.8 cfu. CONCLUSIONS: These data indicate that dento-gingival manipulative procedures comprising a simple dental restoration can lead to a bacteraemia comparable to that from dental extractions. It is suggested that these data may indicate the need for antibiotic prophylaxis for some aspects of conservative dentistry.

Adolescent↗
PubMed2000

Validation of dietary intakes measured by diet history against 24 h urinary nitrogen excretion and energy expenditure measured by the doubly-labelled water method in middle-aged women.

A diet history method for estimating energy and N intakes was validated against 24 h urinary N excretion and energy expenditure measured by the doubly-labelled water (DLW) method. Forty-eight women aged 50-65 years were studied over 1 year. Weighed diet records from 4 d and two 24 h urine collections, for measurement of urinary N excretion, were obtained in each of four seasons. At the end of the year, a diet history was obtained, BMR was measured by whole-body calorimetry, and, in sixteen women, total energy expenditure (EE) was measured by DLW. Energy intake (EI) and N intake (NI) were calculated using food tables. Using weighed records and diet history respectively mean NI were 11.21 (SD 2.09) g and 11.47 (SD 2.40) g (NS) and EI were 8.08 (SD 1.54) MJ and 8.20 (SD 1.86) MJ (NS). Mean urine N:NI and EI:BMR values indicated bias to under-reporting by weighed record and diet history techniques in some individuals, but there was no significant difference between these measures at the group level. The Pearson correlation coefficient (r) for urine N v. NI was 0.81 for the weighed record and 0.38 for the diet history. The correlation of EE v. EI was r 0.48 for weighed record and r 0.11 for diet history. In this study the diet history gave the same estimate of mean intake, but the weighed record appeared to perform better in ranking individuals.

Aged↗
PubMed2000

Within- and between-subject variation in energy expenditure measured by the doubly-labelled water technique: implications for validating reported dietary energy intake.

OBJECTIVES: To estimate the total (CVt), within-subject (CVw) and between-subject (CVb) variation in free-living energy expenditure as measured by the doubly-labelled water (DLW) technique. To examine the limitation of the DLW measurement of energy expenditure for evaluating reported energy intake. To estimate the probable minimum and maximum 'habitual' energy expenditures for a sustainable lifestyle. DESIGN: Review and analysis of individual data from 25 studies with repeat DLW measurements of energy expenditure (EE). RESULTS: Pooled mean CVw derived from 21 studies was 11.8% for EE and 12.3% for physical activity level (PAL). Multiple regression analysis of CVw in 25 studies found a positive association with time span between measurements. At zero time CVw for EE was 8.2% rising to 9.6% at 13 weeks and 15.4% at 52 weeks. At the same time points CVw for PAL was 9.1%, 10.0% and 13.4% respectively. Pooled mean CVt was 13.0% for EE and 10.7% for PAL. CVb calculated from pooled mean CVt and CVw was 20.6% for EE and 7.2% for PAL. 95% confidence limits of PAL in 11 age-sex groups averaged 1.2 to 2.2. CONCLUSIONS: The analysis supported previous estimates of 8% for within-subject variation in DLW measurements including analytic plus inherent biologic variation. Variation that included changes in weight, season and activity increased with increased time between measurements to about 15% at a time span of 12 months. Confidence limits of agreement between EE and reported energy intake were estimated to range from +/-15% to +/-32%. Estimates of the range of usual EE for normally active persons ranged from 1.3 to 2.2.

Adolescent↗
PubMed2000

The sensitivity and specificity of the Goldberg cut-off for EI:BMR for identifying diet reports of poor validity.

OBJECTIVE: To explore the specificity and sensitivity of the Goldberg cut-off for EI:BMR for identifying diet reports of poor validity as compared with the direct comparison of energy intake with energy expenditure measured by doubly-labelled water. DESIGN: Twenty-two studies with measurements of total energy expenditure by doubly-labelled water (EE), basal metabolic rate (BMR) and energy intake (EI) provided the database (n=429). The ratio EI:EE provided the baseline definition of under- (UR), acceptable- (AR) and over-reporters (OR), respectively EI:EE <0.76, 0.76-1.24 and >1.24. Four strategies for identifying under- and over-reporters using the Goldberg cut-off were explored. Sensitivity of the cut-off was calculated as the proportion of UR correctly identified and specificity as the proportion of non-UR correctly identified. RESULTS: UR, AR and OR (by EI:EE) were 34, 62 and 4% respectively of all subjects. When a single Goldberg cut-off for the physical activity level (PAL) of 1.55 was used, for men and women respectively the sensitivity was 0.50 and 0.52 and the specificity 1. 00 and 0.99. Using a cut-off for higher PAL traded specificity for sensitivity. Using the cut-off for a PAL of 1.95, sensitivity was 0. 76 and 0.85 and the specificity 0.87 and 0.78 for men and women respectively. Using cut-offs for mean age-sex specific PAL did not improve sensitivity. When subjects were assigned to low, medium and high activity levels and cut-offs for three different PALs used, sensitivity improved to 0.74 and 0.67 without loss of specificity (0. 97 and 0.98), for men and women respectively. If activity levels for men were applied to the womens' data, sensitivity improved to 0.72. CONCLUSION: To identify diet reports of poor validity using the Goldberg cut-off for EI:BMR, information is needed on each subject's activity level.

Adolescent↗
PubMed2000

Critical evaluation of energy intake using the Goldberg cut-off for energy intake:basal metabolic rate. A practical guide to its calculation, use and limitations.

OBJECTIVES: To re-state the principles underlying the Goldberg cut-off for identifying under-reporters of energy intake, re-examine the physiological principles and update the values to be substituted into the equation for calculating the cut-off, and to examine its use and limitations. RESULTS: New values are suggested for each element of the Goldberg equation. The physical activity level (PAL) for comparison with energy intake:basal metabolic rate (EI:BMR) should be selected to reflect the population under study; the PAL value of 1.55 x BMR is not necessarily the value of choice. The suggested value for average within-subject variation in energy intake is 23% (unchanged), but other sources of variation are increased in the light of new data. For within-subject variation in measured and estimated BMR, 4% and 8.5% respectively are suggested (previously 2.5% and 8%), and for total between-subject variation in PAL, the suggested value is 15% (previously 12.5%). The effect of these changes is to widen the confidence limits and reduce the sensitivity of the cut-off. CONCLUSIONS: The Goldberg cut-off can be used to evaluate the mean population bias in reported energy intake, but information on the activity or lifestyle of the population is needed to choose a suitable PAL energy requirement for comparison. Sensitivity for identifying under-reporters at the individual level is limited. In epidemiological studies information on home, leisure and occupational activity is essential in order to assign subjects to low, medium or high PAL levels before calculating the cut-offs. In small studies, it is desirable to measure energy expenditure, or to calculate individual energy requirements, and to compare energy intake directly with energy expenditure.

Adolescent↗
PubMed2000

Comparison of the incidence of complications at induction and emergence in infants receiving oral atropine vs no premedication.

We studied 120 patients less than 1 yr of age, allocated randomly to receive atropine 40 micrograms kg-1 orally 1 h before operation (group A) or no premedication (group B). All patients underwent a standardized anaesthetic, including inhalation induction with halothane followed by atracurium 0.5 mg kg-1, tracheal intubation and positive pressure ventilation. Monitoring during anaesthesia included heart rate, arterial oxygen saturation, temperature and airway conditions at induction and emergence. The incidence of a decrease in arterial oxygen saturation to 94% or less at induction and recovery was similar in both groups (30.5% at induction, 39% at extubation in group A; 31% at induction, 41% at extubation in group B). There were significantly more airway complications in group B both at induction and emergence (25% and 49%, respectively, compared with 9% and 25% in group A; P < 0.015). Mean heart rate at induction and in the peroperative period was significantly higher in the group receiving atropine (P < or = 0.001). There was an increased incidence of bradycardia (decrease in heart rate of > or = 20%) at induction in the non-premedicated group (23% in group B compared with 10% in group A), but this was not statistically significant. We conclude that the incidence of airway complications at induction and emergence was reduced by orally administered atropine premedication.

Anesthesia Recovery Period↗
PubMed1999

Metabolism and excretion of atorvastatin in rats and dogs.

Atorvastatin (AT) is a second-generation potent inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase, clinically approved for lowering plasma cholesterol. Using a mixture of [D(5)/D(0)] AT and/or [(14)C]AT, the metabolic fate and excretion of AT were examined in rats and dogs following single and multiple oral doses. Limited biliary recycling was examined in one dog after a single dose of AT. AT-derived metabolites in bile samples were identified by metabolite screening of the [D(5)/D(0)] AT molecular clusters using tandem mass spectrometry. Bile was a major route of [(14)C] drug-derived excretion, accounting for 73 and 33% of the oral dose in the rat and dog, respectively. The remaining radioactivity was recovered in the feces; only trace amounts were excreted in urine. Radioactive components identified in rat and dog bile were the para- and ortho-hydroxy metabolites, a glucuronide conjugate of ortho-hydroxy AT, and unchanged AT. Two minor radioactive components were identified as beta-oxidation products of AT with one confirmed as a beta-oxidized AT derivative. The reappearance of AT and major metabolites in bile from a dog administered a sample of its previously excreted bile indicated biliary recycling is an important component in AT metabolism. Multiple dose administration in rats did not alter biliary metabolic profiles. Rat and dog plasma profiles after multiple dose administration were similar and showed no additional metabolites not found in bile. Examination of rat and dog bile and plasma indicates that AT primarily undergoes oxidative metabolism.

Animals↗
PubMed1998

Assessment of selective under-reporting of food intake by both obese and non-obese women in a metabolic facility.

OBJECTIVE: To investigate the degree of bias in under-reporting of food intake in obese and non-obese subjects, hypothesising that under-reporting may be selective for either macronutrient content (carbohydrate (CHO), fat, protein, alcohol), specific food types or eating occasions (meals, snacks). DESIGN: Thirty-three women (18 obese, 15 non-obese) were recruited to a long-stay metabolic facility for 24h. Ad libitum food intake was covertly measured throughout the study and a reported food intake completed at the end of 24h. RESULTS: Reported total daily energy intake was significantly lower than measured intake. Whilst meals were accurately reported, energy from snack foods eaten between meals was significantly under-reported. (P< 0.001) Reported total carbohydrate and added sugar intakes were significantly lower than measured, whilst reported protein and fat intakes were not significantly different from measured. Reported alcohol intake was also considerably lower than measured, but high variability prevented significance. CONCLUSIONS: In both obese and non-obese women the major cause of under-reporting, as assessed by covert study design in subjects restricted within a metabolic facility, is the failure to report between-meal snack foods. There is some evidence for increased under-reporting in high CHO, but no evidence of a bias in under-reporting towards high fat or high protein foods.

Adult↗
PubMed1998

Assessing medical student effectiveness from the psychiatric patient's perspective: the Medical Student Interviewing Performance Questionnaire.

This study sought to develop and pilot-test a patient-completed rating scale of medical student effectiveness while training in psychiatry. Specifically, the study focused on: (1) examining the statistical reliability and validity of a new scale; (2) using the measure to assess patient satisfaction with medical student care during the psychiatry clerkship; and (3) providing some experience-based recommendations about utilizing patient feedback when training medical students in psychiatry. Data were collected over an entire academic year and involved 35 third-year medical students and ratings of their performance provided by 102 psychiatric inpatients. Participants were recruited from three inpatient units and the rate of participation was 62.5%. Principle components analyses of the Medical Student Interviewing Performance Scale (MSIPQ) showed that the overall scale consisted of two, theoretically relevant subscales called 'Rapport' and 'Treatment Feedback.' Each subscale had adequate reliability. In addition, the two subscales were shown to each account for unique variance in two separate questions assessing the patient's overall ratings of rapport and treatment helpfulness. Finally, patients' mean ratings of medical student effectiveness were examined and showed very high levels of satisfaction with the student-patient relationship and the quality of care received. This study is among the first to examine patient satisfaction with medical student providers among a general population of psychiatric inpatients. Recommendations are made about the ways in which the MSIPQ can be used to strengthen the training of medical students in psychiatry.

Adult↗
PubMed1998

Metabolism and excretion studies in mouse after single and multiple oral doses of the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor atorvastatin.

Atorvastatin, [(R-(R,R)]-2-(4-fluorophenyl)-beta, delta-dihydroxy-5-(1-methylethyl)-3-phenyl-4-[(phenyl-amino)carbonyl] -1H-pyrrole-1-heptanoic acid calcium salt (CI-981, AT), is a second generation 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor approved for clinical use as a cholesterol lowering agent. The disposition and metabolism of AT, including potential CYP450 induction, was investigated in mice administered an oral dose of [14C]AT (free acid) on study days 1 and 14. Peak plasma radioactivity concentrations occurred 1 hr postdose after both single- and multiple-dose administration and declined rapidly thereafter. Total plasma radioactivity levels in mice receiving the multiple dose were approximately 50% of levels observed after single-dose administration. Plasma metabolic profiles, which provided evidence of extensive metabolism, remained similar. Feces was the major route of AT-derived radioactivity elimination. Fecal profiles showed extensive metabolism with qualitatively similar profiles after single- and multiple-dose administration; however, quantitative differences were apparent. Metabolites identified in plasma and feces include hydroxylated, beta-oxidized, and unsaturated derivatives of AT. Most metabolites had undergone beta-oxidation. In mice receiving multiple 1 mg/kg doses of AT, no effect on spectral P450 concentration was found, and only a minor increase was observed at the 200 mg/kg dose level. Catalytic activities of CYP4501A, -2B, and -3A were not significantly affected; CYP4A activity decreased in a dose-dependent manner. Administration of multiple doses resulted in lower systemic plasma levels of total AT-derived radioactivity not readily explained by these studies. In mice, the majority of metabolites are formed primarily through the beta-oxidation pathway.

Administration, Oral↗
PubMed1997

Validation of dietary intakes of protein and energy against 24 hour urinary N and DLW energy expenditure in middle-aged women, retired men and post-obese subjects: comparisons with validation against presumed energy requirements.

OBJECTIVES: To compare validation of reported dietary intakes from weighed records against urinary nitrogen excretion and energy expenditure measured by DLW, and to examine the utility of the Goldberg cut-off for EI:BMR in the identification of under-reporters. DESIGN: Energy (EI) and nitrogen (protein) intake (NI) were measured by 16 d of weighed diet records collected over 1 y. They were validated against urinary nitrogen excretion in 5-8 (mean 6.0) 24 h urine collections and total energy expenditure (EE) measured by doubly labelled water (DLW). Basal metabolic rate (BMR) as measured by whole body calorimetry in women or bedside ventilated hood (Deltatrac) in men. Individual subjects were identified as under-reporters if Urine N:NI was > 1.00 or if EI:EE was < 0.79. The agreement between the two ratios in detecting under-reporting was examined. The results from the direct validation by DLW were also compared with validation using the Goldberg cut-off for EI:BMR (Goldberg et al, 1991). SUBJECTS: Eighteen women aged 50-65 y and 27 men aged 55-87 y were selected from participants in two larger dietary surveys as representing the full range of dietary reporting as measured by Urine N:NI. Data from a previous study of 11 post-obese subjects were also included. RESULTS: The two ratios, Urine N:NI and EI:EE, were significantly related (r = -0.48, P < 0.01). Using the above cut-offs, seven (4F, 3M) subjects were identified as under-reporters by both methods, one (1M) by Urine N:NI only and 8 (3F, 5M) by EI:EE only. There was close agreement in post-obese subjects where 6 subjects showed a substantial degree of under-reporting by both methods (r = -0.87, P < 0.001). The correlation between direct validation by DLW and EI:BMRest was 0.65 (P < 0.001). Some limitations of the Goldberg cut-off for identifying individual under-reporters were demonstrated. CONCLUSIONS: EI:EE provides an estimate of the degree of under-reporting of energy at the group and individual level. Urine N:NI identifies under-reporting of protein intake and the most obvious under-reporters of energy, but is probably of lesser value in estimating the overall degree of under-reporting of energy at group level. Good validation by EI:BMR depends on knowledge of physical activity at both group and individual level. However, the correlation of 0.65 between EI:EE and EI:BMRest suggests that EI:BMR could be usefully incorporated into analysis of data from epidemiological studies. Validation measures consisting of at least predicted EI:BMR ratios and urinary measures should be incorporated into dietary surveys. SPONSORSHIP: This work was funded by the Ministry of Agriculture Fisheries and Food, the Medical Research Council, the Cancer Research Council and the Swedish Medical Research Council and the Henning and Johan Throne-Holst Foundation.

Aged↗