Biomedical subjects

E O Smith

Publications and source records attributed to E O Smith.

At least 55 records · Page 3Linked to original sources

PubMed1998

Early feeding, antenatal glucocorticoids, and human milk decrease intestinal permeability in preterm infants.

To determine the effects of age, feeding regimen, and antenatal glucocorticoids on intestinal permeability, preterm infants (n = 132) were stratified by gestational age and by diet (mothers' own milk versus preterm formula), and assigned randomly to one of four feeding regimens: early-continuous, early-bolus, standard-continuous, and standard-bolus. At 10, 28, and 50 d of age permeability was determined by measuring the ratio of lactulose/ mannitol in the urine after the two sugars were administered enterally for 30 h. The mean (+/-SE) birth weight and gestational age of the infants were 1044 +/- 13 g and 27 +/- 0.1 wk, respectively. Permeability changed as a function of age (p = 0.003). Early feeding was associated with a reduction in permeability at 10 d of age (p = 0.01). Antenatal steroid administration was associated with decreased permeability at 28 d of age (p = 0.017). The feeding of human milk (versus formula) was associated with decreased permeability at 28 d of age (p = 0.02). Continuous versus bolus feeding did not affect permeability.

Aging↗

PubMed1998

Serum leptin concentrations in Caucasian and African-American girls.

Because African-American girls are heavier, taller, and mature earlier than Caucasian girls, we hypothesized that the serum leptin concentration differs between the two groups. Serum leptin concentrations were measured by immunoassay in 12-h fasted blood samples collected from 79 Caucasian and 57 African-American girls between 8 and 17 yr of age. Body composition was measured by dual-energy x-ray absorptiometry, sexual maturity by physical examination, and physical fitness by treadmill testing. Serum leptin concentrations were positively correlated (P < 0.01) with maturation, body fatness, and insulin and were higher (6.6 ng/mL, P < 0.01) in the African-American girls after adjusting for age. The difference remained significant (P < 0.01) but was reduced to 3.2 ng/mL after controlling for differences in maturation, fat mass, and physical fitness. The higher serum leptin levels might play an important role in the accelerated growth and sexual maturation of African-American girls.

Adolescent↗

PubMed1997

The acetylcholine releaser linopirdine increases parietal regional cerebral blood flow in Alzheimer's disease.

Centrally acting cholinergic drugs have been reported to increase regional cerebral blood flow (rCBF) as measured by single photon emission computed tomography (SPECT) in brain regions affected by Alzheimer's disease (AD). We studied the effects of the acetylcholine releaser linopirdine (LPD) on SPECT rCBF in patients with probable AD. Twenty-four AD patients (12 M, 12 F; mean age +/- SD = 68.9 +/- 8.2 years) and 13 healthy controls (8 M, 5 F; 68.4 +/- 8.0 years) participated. AD patients were scanned with 20 mCi of Tc99m-ECD at baseline and following 4 weeks of treatment with LPD 40 mg TID (n = 15) or placebo TID (n = 9) in a double-blind trial. Healthy subjects were scanned for comparison with baseline AD scans. Cortical/cerebellar rCBF ratios were derived for nine cortical structures. The combined parietal association cortex showed a 20.6% reduction in patients relative to controls. Patients treated with LPD showed an increase in parietal rCBF of 4.1 +/- 5.8%; whereas those treated with placebo showed a decrease of -2.0 +/- 7.4% (F = 5.13; df = 1, 22; P = 0.03). These data support the conclusion that rCBF abnormalities in AD are, in part, truly "functional" and can be selectively altered with pharmacological interventions. The parietal activation seen with LPD and other cholinergic AD drug therapies suggests the importance of measuring parietal lobe neuropsychological function in the course of evaluating these drugs.

Acetylcholine↗

PubMed1997

Bone mineral changes in young women with hypothalamic amenorrhea treated with oral contraceptives, medroxyprogesterone, or placebo over 12 months.

OBJECTIVES: The objectives of this study were to assess (1) whether treatment with oral contraceptives, in comparison with medroxyprogesterone and placebo, improved bone mineral in women with hypothalamic amenorrhea and (2) whether treatment with medroxyprogesterone, in comparison with placebo, improved bone mineral in women with hypothalamic oligomenorrhea. STUDY DESIGN: The study was a randomized, controlled clinical trial. Twenty-four white women, aged 14 to 28 years, with hypothalamic amenorrhea or oligomenorrhea were prospectively enrolled for a 12-month intervention period. Amenorrheic subjects were randomized to receive oral contraceptives, medroxyprogesterone, or placebo. Oligomenorrheic subjects were randomized to receive medroxyprogesterone or placebo. Bone mineral was measured by dual-energy x-ray absorptiometry at baseline and at 6 and 12 months. RESULTS: In amenorrheic subjects spine and total body bone mineral measurements at 12 months were greater in the oral contraceptive group than in the medroxyprogesterone and placebo groups when baseline bone mineral measurements, body weight, and age were controlled for (p < or = 0.05). There were no differences in hip bone mineral calcium and bone mineral density measurements at 12 months among the three groups. In oligomenorrheic subjects there was no detectable improvement in bone mineral associated with medroxyprogesterone use. CONCLUSIONS: This study supports the hypothesis that oral contraceptive use in women with hypothalamic amenorrhea will improve lumbar spine and total body bone mineral.

Adolescent↗

PubMed1997

Does extracorporeal membrane oxygenation benefit neonates with congenital diaphragmatic hernia? Application of a predictive equation.

The overall survival of neonates with congenital diaphragmatic hernia (CDH) remains poor despite the advent of extracorporeal membrane oxygenation (ECMO). Attempts at accurately predicting survival have been largely unsuccessful. The purpose of this study was twofold: (1) to identify independent predictors of survival from a cohort of CDH neonates treated at the authors' institution when ECMO was not available and combine them to form a predictive equation, and (2) to apply the equation prospectively in a cohort of CDH neonates, treated at the same institution when ECMO was available, to determine whether ECMO improves outcome. From the clinical data of 62 CDH neonates treated at the authors' center by the same team of university neonatologists and pediatric surgeons between 1983 and 1993 (before ECMO availability), 15 preoperative and seven operative variables were selected as potential independent predictors. When subjected to multivariate, stepwise logistic regression analysis, four variables were identified as statistically significant (P < .05), independent predictors of survival: (1) ventilatory index (VI), (2) best preoperative PaCO2, (3) birth weight (BW), and (4) Apgar score at 5 minutes. When combined via logistic regression analysis, the following predictive equation was formulated: P (probability of survival to discharge) = [1 + e(x)]-1 where x = 4.9 - 0.68 (Apgar) - 0.0032 (BW) + 0.0063 (VI) + 0.063 (PaCO2). Applying a standard cut-off rate of survival at less than 20%, the equation yielded a sensitivity of 94% and a specificity of 82% in identifying the correct outcome of patients treated with conventional ventilatory management. The overall survival rate was 66%. Since the availability of ECMO at the center, 32 CDH neonates were treated using the same conventional ventilatory treatment and surgical repair by the same university staff. The overall survival rate was 69%. The predictive equation was applied prospectively to all neonates to determine predicted outcome, but was not used to decide the treatment method. Eighteen neonates received conventional therapy alone; 16 of 18 survived (89%). Fifteen of the 16 patients who survived had their outcomes predicted correctly (94%). Fourteen neonates did not respond to conventional therapy and required ECMO; 6 of 14 survived (43%). Six of the eight patients predicted to survive, lived (75%). All six patients predicted to die, died despite the addition of ECMO therapy (100%). The mean hospital cost, per ECMO patient who died, was $277,264.75 +/- $59,500.71 (SE). An odds ratio analysis, using the four independent predictors to standardize for degree of illness, was performed to assess the risk associated with adding ECMO therapy. The result was 1.25 (P = 0.75). Although the cohort was not large enough to eliminate significant beta error, the data strongly suggested no advantage of ECMO. At this center, absolute survival rates for neonates with CDH have not been significantly altered since ECMO has become available (66% v 69%). The authors conclude that the predictive equation remains an accurate measurement of survival at their center even when ECMO is used as a salvage therapy. The method of creating a predictive equation may be applied at any institution to determine the potential outcome of CDH neonates and assess the effect of ECMO, or other salvage therapies, on survival rates.

Decision Support Techniques↗

PubMed1997

Interviewing techniques with adolescents in primary care.

PURPOSE: Privacy is of utmost concern to adolescents seeking advice regarding life-style and behavior choices. Lack of privacy and confidential health services are barriers to adolescents' access to health care. This study describes primary care physicians' practices with regard to inviting parent(s) to leave the room in order to interview the teen alone, and the factors associated with use of this technique. METHOD: A cross-sectional random survey of 1,630 pediatricians, internists, and family practitioners in a large metropolitan area was performed using a confidential mailed questionnaire. RESULTS: The majority of the physicians were in private practice, male, board certified, Caucasian, and did not have a subspecialty. Forty-nine percent of the respondents "almost always" or "always" invite parent(s) to leave the room in order to interview the teen alone. Physicians who were female, board certified, and completed residency from 1974-94 were most likely to use this technique. Among physicians who frequently employ this strategy, the decision to interview the teen alone varied according to the clinical scenario. Using logistic regression analysis, only gender and board certification were significantly related to use of this interviewing method. CONCLUSION: A large proportion of physicians do not interview their adolescent patients alone, therefore, not affording them privacy to discuss confidential health concerns. Future research should focus on developing and validating methods to teach physicians skills to interview adolescents privately.

Adolescent↗

PubMed1997

Changes in fat-free mass and fat mass in postpartum women: a comparison of body composition models.

OBJECTIVES: (1) To compare 2-, 3- and 4-component models of body composition based on total body water (TBW), underwater weighing (UWW), skinfold thicknesses (SF), total body potassium (TBK), dual-energy X-ray absorptiometry (DXA) and total body electrical conductivity (TOBEC); (2) to compare postpartum changes in body composition estimated by the 2-, 3- and 4-component models and (3) to test for an effect of pregnancy or lactation on the hydration, density and potassium content of fat free mass (FFM) in postpartum women. DESIGN: Longitudinal measurements of body composition at 3, 6 and 12 months postpartum. SUBJECTS: Thirty-five healthy postpartum women, aged 30.2 +/- 3.5 y. MEASUREMENTS: Body composition was estimated by 2-component models based on TBW, UWW, SF, TBK, DXA or TOBEC; 3-component models based on TBW and UWW (Fuller 3, Siri 3); and a 4-component model (Fuller 4) based on TBW, UWW and bone mineral content. RESULTS: Systematic differences were seen among the various body composition models, with the following ranking from lowest to highest estimate of fat mass (FM): TOBEC, TBW, Fuller 3, Siri 3, Fuller 4, UWW, SF, TBK, and DXA. Estimated changes in FFM and FM were not significantly different among methods, except for the 3-6 months FFM and FM changes estimated from TBW, which differed from SF, DXA, and TOBEC. Pregnancy-induced changes in the hydration, density and potassium content of FFM were not evident by 3 months postpartum (0.73 +/- 0.02, 1.099 +/- 0.015 kg/l and 2.31 +/- 0.10 g/kg, respectively). CONCLUSION: In spite of systematic differences among body composition models for the measurement of FFM and FM, changes in FFM and FM did not differ significantly among the models. Since there was no apparent effect of pregnancy or lactation on the postpartum composition of FFM, 2-component models of body composition are acceptable for use in postpartum women beyond the puerperium.

Adult↗

PubMed1997

Body fat estimation in late pregnancy and early postpartum: comparison of two-, three-, and four-component models.

Accurate methods for determining body fat mass during reproduction are necessary to evaluate energy balance. However, determination of fat mass is complicated during pregnancy by the accretion of water, which invalidates assumptions underlying standard two-compartment models. The extent to which the variability in body water during pregnancy invalidates use of pregnancy-corrected two-compartment models for determination of fat mass in individual women is unknown. Moreover, it is unclear whether body water returns to nonpregnant values by 2 wk postpartum, which is frequently used as the baseline in studies of postpartum women. The present study uses a four-component model as a criterion for evaluating two- and three-component models. Fifty-six healthy, normotensive women between the ages of 19 and 35 y were studied at 36 +/- 1 wk gestation and 15 +/- 2 d postpartum. Total body water (TBW), total body potassium (TBK), body density, and bone mineral content were measured by deuterium dilution, whole-body potassium counting, hydrodensitometry, and dual-energy X-ray absorptiometry (postpartum only), respectively. At 2 wk postpartum, hydration and density of fat-free mass (FFM) had not returned to nonpregnant values, and differed between lactating and nonlactating women (P < 0.05). Accordingly, standard TBW and body density estimates of fat mass differed from four-component estimates at both time points (P < 0.005). Moreover, our data indicate that even when pregnancy-specific values for hydration or density of FFM are used in TBW and body density models, individual fat mass estimates may differ by > 3 kg from the four-component value. Fat mass by TBK may differ by > 10 kg from fat mass by the four-component model during pregnancy, and by 6 kg postpartum. Use of standard two-compartment models to estimate fat mass results in significant error both during pregnancy and at 2 wk postpartum. Pregnancy-corrected two-compartment models produce reliable mean fat mass estimates during pregnancy, but individual fat mass estimates may vary widely from four-component values.

Absorptiometry, Photon↗

PubMed1997

Maternal energy balance and lactation performance of Mesoamerindians as a function of body mass index.

The effect of maternal energy balance in conjunction with body energy reserves on lactation performance has not been fully elucidated in humans. Energy balance was computed from changes in weight and body composition over 6 mo postpartum in 21 Otomi Indian women with relatively low postpartum body mass indexes (BMIs; in kg/m2, 21.4 +/- 0.9) and 19 with relatively high BMIs (25.7 +/- 1.9). Body fat was determined by deuterium dilution. Milk production was estimated by 24-h test weighing. Macronutrient content of human milk was measured by standard techniques. In both groups weight declined over the 6 mo postpartum (P = 0.04). In the lower BMI group only, body fat (kg, % of wt) decreased significantly (P = 0.04). Milk fat concentration was positively correlated with body fat at 3 and 6 mo (r = 0.32 and 0.40; P = 0.04 and 0.01, respectively). Energy balance was not associated with milk production or composition, nutrient secretion into milk, or infant growth velocity, except at 6 mo, when energy balance was positively correlated with milk energy and fat concentration in the lower BMI group (r = 0.55; P = 0.01). Fat concentration was lower in the lower BMI group (P = 0.04). Because of the inverse correlation between milk production and milk fat at 3 and 6 mo (r = -0.47 and -0.43, respectively; P = 0.01), fat secretion into milk did not differ between groups. Infant growth velocities did not differ significantly between groups. In conclusion, negative energy balance in conjunction with lower energy reserves did not adversely affect lactation performance or infant growth in this population of Otomi Indians.

Adolescent↗

PubMed1997

Total energy expenditure and physical activity level of lactating Mesoamerindians.

Energy-sparing mechanisms may be elicited to meet increased energy requirements imposed by lactation on women who reside in poor, rural communities in developing countries. The objectives of this study were to measure total energy expenditure and its components, basal and activity energy expenditure, and to investigate their relationships with lactation performance in a total of 40 rural Mesoamerindians stratified according to postpartum body mass index. Total energy expenditure and fat-free mass were measured by the doubly labeled water method, and basal metabolic rate was determined by indirect calorimetry at 3 and 6 mo postpartum. Physical activity level was taken as the ratio of total energy expenditure to basal metabolic rate. Milk energy output, which is not included in total energy expenditure, was computed from 24-h milk intake (test-weighing) and energy concentration of milk (bomb calorimetry). Anthropometric measurements revealed negligible mobilization of tissue stores. Mean (+/- SD) total energy expenditures were 8912 +/- 1296 kJ/d and 9253 +/- 1298 kJ/d for the lower and higher body mass index groups, respectively. Adjusted for fat-free mass, total energy expenditure was higher in the lower body mass index group (P = 0.05). Adjusted for fat-free mass, basal metabolic rate did not differ between groups. Physical activity level was significantly higher in the lower body mass index group (P = 0.03). Lactation performance did not differ between groups and was not associated with total energy expenditure or its components. Despite the maintenance of energy balance and heightened energy requirements of lactation, energy-sparing mechanisms were not evident in these lactating Mesoamerindians.

Adolescent↗

PubMed1997

Resource utilization among neonatologists in a university children's hospital.

OBJECTIVE: We studied factors affecting length of hospital stay and resulting hospital charges among patients managed by two separate groups of neonatologists in the same academic health science center. DESIGN: Retrospective analysis of clinical and financial data base information. METHODS: Neonatal intensive care was provided in the same acute care nursery in a large university children's hospital by: (1) neonatologists in a full-time academic division (group A) and (2) a group associated with a private managed care organization (group B). Clinical and financial parameters of all neonates admitted in fiscal year 1994 were compared for the two provider groups. Stepwise regression analysis was used to evaluate factors influencing hospital charges and length of hospital stay (LOS) and to adjust for differences in clinical variables between the two groups. RESULTS: Group A physicians provided care for 340 infants, while 137 were treated by those of group B. Group A included older patients, more outborns, more level III patients, more sepsis, more intermittent positive pressure ventilation, and more patent ductus arteriosus. The incidence of transient tachypnea of the newborn was higher among group B patients. Hospital charges were primarily determined by LOS, which was similar for the two groups. When the data were corrected for differences in risk and patient acuity, however, a significant relationship between physician group and LOS was demonstrated, with LOS being an average of 7.8 days shorter for group A. A net reduction of $3 114 969 in hospital charges might have been realized had group A physicians provided care for all study patients. CONCLUSIONS: Hospital charges were determined by LOS. In this setting, academic neonatologists produced shorter LOS and comparable clinical outcomes, despite caring for a population at greater risk. The reduction in LOS could have resulted in more than $3.1 million in annualized savings had the academic group provided care for all of the study patients.

Analysis of Variance↗

PubMed1997

Adipose tissue beta-adrenergic and A1 adenosine receptors in suckling pigs.

During the first few weeks after birth, major changes occur in porcine adipocyte lipid metabolism. Two of the important receptors controlling lipid metabolism in adipocytes are the beta-adrenergic receptors (betaAR) and the A1 adenosine receptors (A1R). To gain insight into the role of these receptors in modulating neonatal adipocyte lipid metabolism, we measured receptor affinity and number in suckling pigs. Adipose tissue from crossbred (X-Bred) and genetically obese suckling pigs at 0, 3, 10, and 17 d of age was used to prepare crude membranes. The betaAR and A1R number and affinity were measured in membranes by equilibrium saturation binding with radioligands. Obese pigs were smaller than X-Bred pigs (average weight = 1.62 and 2.43 kg for obese and X-Bred, respectively; P < .01). Osmium-fixed adipocytes were larger in obese pigs than in X-Bred pigs (average cell diameter = 34.4 and 30.1 microm for obese and X-Bred, respectively; P < .01). In the obese and X-Bred pigs, the affinity of the betaAR for iodocyanopindolol was greater (lower Kd) at 17 d than at the younger ages (average Kd = 177 pM at 17 d compared with > 330 pM at younger ages; age effect P < .01). The pattern for the betaAR number was complex; the lowest receptor number was at 10 d of age in obese and X-Bred pigs (average number = 41 at 10 d compared with > 65 fmol/mg protein at older and younger ages; age effect P = .03). The higher betaAR Kd and the lower receptor number in younger animals suggest less regulation by physiologic concentrations of epinephrine and norepinephrine. This would allow greater anabolic lipid metabolism to proceed during the neonatal period, when adipocytes increase four- to sixfold in volume. There were no measurable A1R at any of these early ages; thus, adenosine control mechanisms to counteract the betaAR and provide negative controls to lipid accretion are not operable in suckling pigs.

Adipocytes↗

PubMed1997

Influence of nutritional weaning on porcine adipocyte beta-adrenergic and adenosine A1 receptors.

Obese and crossbred (X-Bred) pigs were removed from sows at 14 d of age and given ad libitum access to a high-fat, milk-based diet. A subset of pigs fed this diet were killed at 28 and 49 d of age. At 28 d, another subset of pigs was given ad libitum access to a low-fat, grain-based diet and were killed at 31, 35, and 49 d of age (nutritionally weaned for 3, 7, and 21 d, respectively). Dorsal subcutaneous adipose tissue was obtained at death and adipocytes were prepared by incubation with collagenase. A portion of the cells was fixed with osmium to determine size and number; remaining cells were lysed in hypotonic media and centrifuged to yield a crude membrane fraction. The beta-adrenergic receptor (beta-AR) and A1 adenosine receptor (A1R) affinity and number were measured in the membranes by equilibrium saturation ligand binding. Obese pigs had a lower body weight than X-Bred pigs at all ages (P < .05). Obese pigs tended (P for volume > .1 but < .2) to have larger adipocytes than X-Bred pigs. The beta-AR affinity did not differ between obese and X-Bred pigs. There were fewer beta-AR per milligram of membrane protein in obese than in X-Bred pigs at 28 and 49 d of age when fed the high-fat, milk-based diet (P < .01). However, beta-AR number expressed per cell or unit cell surface area did not differ between genetic groups. As pigs of either genetic group continued to be fed the low-fat, grain-based diet, the beta-AR decreased when expressed per milligram of protein or unit cell surface area (P < .05) and tended to decrease when expressed per cell. Obese and X-Bred pigs fed the high-fat, milk-based diet had more beta-AR than respective pigs fed the low-fat, grain-based diet when data were expressed per milligram of protein (P < .01) but not when expressed per cell or unit surface area. The A1R were only detectable in 2 of 16 X-Bred litters but were more developed in adipocytes of obese pigs, being measurable in 8 of 14 litters. The A1R number, expressed per milligram of protein, was lower in obese pigs fed the milk-based diet than in those fed the grain-based diet (P < .05). These findings suggest the decreased beta-AR number after nutritional weaning, or the transition from a high-fat to low-fat diet, may contribute to fat accretion in pigs. Furthermore, the lower number of beta-AR in obese than in X-Bred pigs may contribute to the obesity.

Adipocytes↗

PubMed1996

Quantitative echocardiographic analysis of the aortic arch predicts outcome of balloon angioplasty of native coarctation of the aorta.

BACKGROUND: The use of balloon angioplasty for treatment of native aortic coarctation is controversial. Cineangiographic data suggest that aortic arch hypoplasia and isthmic narrowing are associated with angioplasty failure. This study of echocardiographic measurements of preangioplasty aortic arch morphology was performed to identify potential anatomic predictors of outcome noninvasively. METHODS AND RESULTS: The preangioplasty echocardiograms of 105 patients 3 days to 17 years old with native coarctation of the aorta were analyzed off-line. Angioplasty was considered successful if the residual coarctation gradient was < 20 mm Hg and no intervention for recoarctation occurred. Univariate analysis identified young age at angioplasty, presence of a patent ductus arteriosus, and the diameters of the aortic isthmus, distal transverse arch, and aortic valve as predictors of early and late outcomes. Multivariate analysis showed that the preangioplasty aortic isthmus z value was the best independent predictor of outcome, eliminating the effect on outcome of age and associated cardiac defects. An isthmus z value < or = -2.16 predicted early failure with 91% sensitivity and 85% specificity. Kaplan-Meier analysis demonstrated that 90% of patients with an isthmus z value > -1.0 remained free of recoarctation at late follow-up, whereas 89% of patients with a preangioplasty isthmus z value < or = -2.0 developed recoarctation within 36 months. CONCLUSIONS: Echocardiographic measurements of the aortic arch predict both early and late outcomes of balloon angioplasty for native aortic coarctation, and the preangioplasty aortic isthmus z value was the best independent predictor. Quantitative aortic arch analysis may improve selection of angioplasty candidates who are likely to benefit from the procedure.

Adult↗

PubMed1996

Acute cocaine effects on absolute cerebral blood flow.

Cocaine use has been associated with vasoconstriction and stroke, and several studies have demonstrated that it decreases relative cerebral blood flow (rCBF) in humans. However, rCBF has not been quantitated. We compared 40 mg IV cocaine hydrochloride to placebo effects on absolute rCBF in four cocaine users using 99mTc-HMPAO SPECT with a modified microsphere model for CBF quantitation. Cocaine produced significant decreases in rCBF in all regions studied with a mean decrease of 30% in absolute whole brain blood flow (P = 0.002) which was 3-fold greater than relative blood flow changes.

Adult↗

PubMed1996

Are basal metabolic rate prediction equations appropriate for female children and adolescents?

The basal metabolic rate (BMR), which accounts for 50-70% of total energy expenditure, is essential for estimation of patient and population energy needs. Numerous equations have been formulated for prediction of human BMR. Most equations in current use are based on measurements of Caucasians performed more than four decades ago. We evaluated 10 prediction equations commonly used for estimation of BMR in 76 Caucasian and 42 African-American girls between 8 and 17 yr of age against BMR measured by whole-body calorimetry. The majority of the prediction equations (9 of 10) overestimated BMR by 60 +/- 46 kcal/day (range, 15-176 kcal/day). This overestimation was found to be significantly greater (P < 0.05) for African-American (77 +/- 17 kcal/day) than for Caucasians (25 +/- 17 kcal/day) in six equations, controlling for age, weight, and sexual maturity. We conclude that ethnicity is an important factor in estimation of the BMR and that the current prediction equations are not appropriate for accurate estimation of the BMR of individual female children and adolescents.

Adolescent↗

PubMed1996

Practice variations by population: training significance.

OBJECTIVE: This study sought to examine variations in the frequency of procedures performed and patterns of care of sick infants and older children by general pediatricians in different sized communities. The results of the study will be considered in developing relevant educational experiences for postgraduate trainees. METHODOLOGY: Questionnaires were sent to 1412 Texas pediatricians requesting frequency information for 29 procedures and whether they provided various levels of care to sick infants and older children. Responses were tabulated by the size of the community in which each pediatrician practiced. RESULTS: Fifty-four percent of the questionnaires were returned. The proportion of pediatricians performing each procedure was significantly different for all but 8 of the 29 procedures between communities of less than 100,000 and more than 100,000 population. For all procedures with significant differences, the proportion of physicians performing the procedures was significantly greater for pediatricians practicing in communities of less than 100,000 population. No significant difference was found between the proportion of pediatricians providing newborn level II and III care; however, more than 65% of both groups provided level II care. Physicians in communities of less than 100,000 population were more likely to provide intermediate and intensive care beyond the newborn period. CONCLUSION: The general practice rotation in the community setting will not provide adequate training experiences for many of the procedures currently being performed by general pediatricians.

Child↗

PubMed1996

Comparison of technetium-99m-HMPAO and technetium-99m-ECD cerebral SPECT images in Alzheimer's disease.

UNLABELLED: SPECT has shown increasing promise as a diagnostic tool in Alzheimer's disease (AD). Recently, a new SPECT brain perfusion agent, 99mTc-ethyl cysteinate dimer (99mTc-ECD) has emerged with purported advantages in image quality over the established tracer, 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO). This research aimed to compare cerebral images for 99mTc-HMPAO and 99mTc-ECD in discriminating patients with AD from control subjects. METHODS: Twenty-four AD patients (mean age +/- s.d. = 68.9 +/- 8.2 yr) and 13 healthy subjects (68.4 +/- 8.0 yr) were scanned sequentially with 20 mCi of each tracer using the CERASPECT system within 1 mo. Scanning began on average 11.5 +/- 2.8 min after 99mTc-HMPAO injection and 41.8 +/- 10.1 min after 99mTc-ECD. A ratio, R, was derived of count densities in "typically affected" brain structures (parietal and temporal association cortices) to "unaffected" structures (cerebellum, basal ganglia, thalamus, occipital cortex, and sensorimotor cortex). RESULTS: Analysis of variance revealed significant interaction between diagnostic group and radiopharmaceutical (F = 4.71; df = 1.35; p = 0.04), with 99mTc-ECD demonstrating better separation of R values between AD patients and control subjects than 99mTc-HMPAO. Receiver operating characteristic (ROC) analysis, revealed no significant difference in the ability of the two tracers to correctly classify AD patients and control subjects. Both tracers showed high diagnostic accuracy (99mTc-ECD: sensitivity = 100%, specificity = 92%; 99mTc-HMPAO: sensitivity = 100%, specificity = 85%). CONCLUSION: Technetium-99m-ECD shows greater contrast than 99mTc-HMPAO between affected and unaffected brain structures in AD when patients are compared to age-matched control subjects. Both tracers perform equally well in correctly classifying patients and control subjects.

Aged↗