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Both bone mass by densitometry and speed of sound (SOS) from quantitative ultrasound of the bone (QUS) are directly related to bone strength. However, reports of lower bone mass but higher SOS in neonates with intrauterine growth deficit lead to apparent contradictory conclusions on bone strength. Three groups of infants were studied: small for gestation (SGA) with birth weights ≤10th percentile for gestation and 2 control groups with appropriate birth weights (11th to 90th percentile) for gestation (AGA): matched to SGA group for gestation and birth weight, respectively. SOS was measured with a commercial QUS instrument (Sunlight Omnisense 7000, Sunlight Medical Ltd, Tel Aviv, Israel) and 2 manufacturer supplied ultrasound probes (CS and CR) for small bones. The SGA group had significantly (p<0.01) higher SOS compared with weight matched but gestational less matured control group by an average of 54m/s with the CS probe and 80m/s with the CR probe but not significantly different from gestation-matched AGA group. SOS values from both probes were significantly correlated (r=0.71-0.91) but were significantly different between probes. Probe failure occurred with both probes. We conclude that QUS SOS values in SGA neonates are a reflection of a continuum of intrauterine maturation of the skeleton., (Copyright © 2011 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.)

Bone quantitative ultrasound generated speed of sound (SOS) is a marker of bone strength. However, critical evaluation of its validity for use in small bones is extremely limited, and SOS data may not be consistent with data obtained from dual energy x ray absorptiometry, another marker of bone strength. We report the SOS values pre and postinjection of s.c. fat using a chicken bone model; and in large for gestation and appropriate for gestation neonates to determine the influence of s.c. fat. Average SOS were lowered for the chicken bones postfat injection by 36 m/s (CS probe) and 58 m/s (CR probe), and in large for gestation group by 75 m/s (CS probe) and 51 m/s (CR probe) (p = 0.03-0.004 paired t test) although SOS measurements from each probe are significantly correlated within the large (r = 0.78) and appropriate (r = 0.83) for gestation group. Failed SOS measurements occurred significantly more frequently in the postinjection studies regardless of the probe used in the chicken bone model and for the CS probe in large for gestation neonates. The lowered bone quantitative ultrasound measurements in large for gestation neonates is likely a measurement artifact from increased s.c. fat.

Background: Leptin and its soluble receptor (sOB-R) are important to regulation of body composition but there are no data on the developmental variations in these plasma variables and their relationship with body composition measurements,, Methods: Weight, length, and body composition (bone, fat and lean mass) by dual energy absorptiometry, and plasma variables were measured in healthy infants at 2, 4, 8 and 12 months., Results: 15 whites and 29 African Americans (21 males and 23 females) with mean birth weight 3357 +/- 45 (SEM) g and gestation of 39.3 +/- 0.17 weeks were studied. The overall Z score for weight, length and weight for length during the study were 0.00 +/- 0.15, -0.08 +/- 0.11 and 0.12 +/- 0.14 respectively. With increasing age, plasma leptin (1.0 to 18.2, median 5.5 ng/mL) and sOB-R:leptin molar ratio (10.1 to 247.4, median 59.9) were lowered (r = -0.47, p < 0.01; and r = -0.37, p < 0.05 respectively), best predicted by weight Z score and percentage of fat mass, and higher in African American and female. Presence of body composition measurements eliminated the race and gender effect on the plasma variables. Plasma sOB-R (49.5 to 173.9, median 81.3 ng/mL) did not change significantly with age and was correlated and predicted only by body composition measurements., Conclusion: In healthy growing infants, plasma leptin but not sOB-R decreases with age. Gender, race and anthropometric measurements are additional physiological determinants predictive of plasma leptin and the receptor:ligand ratio. However, body composition is the only variable that can predict plasma leptin and its soluble receptor and the receptor: ligand ratio; and body composition measurements eliminated the race and gender effect on these plasma variables.

Background: Despite the theoretical benefits of nutrient-enriched formula given to preterm infants after hospital discharge, its role in reversing growth deficits after hospital discharge remains poorly defined., Objective: The aim was to determine the effect of different formulas on the growth, bone mass, and body composition of preterm infants after hospital discharge., Design: This was a randomized, double blind comparison of a nutrient-enriched formula (EF) and a formula for term infants (TF) given for 1 y after hospital discharge. Compared with the TF, the EF had a higher energy density and higher contents of protein, calcium, and phosphorus (by 10%, 21%, 44%, and 11%, respectively) and higher contents of almost all other nutrients (by >or=10%)., Results: Birth weights of the infants were 630-1620 g (median: 1250 g) and gestational ages were 24-34 wk (median: 29 wk). TF resulted in significantly greater weight, length, head circumference measurements, and their respective z scores on the basis of age- and sex-specific norms. At the end of the study, the mean z scores for the corrected age of infants in the TF group were -0.37 for weight, 0.001 for length, and 0.50 for head circumference. The TF group also had significantly greater dual-energy X-ray absorptiometry measured bone and lean and fat mass than did the EF group (P < 0.05 for all comparisons)., Conclusions: The use of EF for preterm infants after hospital discharge shows no advantage over TF in growth, bone mineralization, and body composition. More studies are needed to determine the optimal postdischarge nutrition support for preterm infants.

Aim: Twin gestations are associated with disturbed fetal growth. The aim of this study was to compare body composition measurements of twins to those of singletons., Methods: Anthropometric and dual energy X-ray absorptiometry (DXA) measurements were performed in twins and in matched singleton neonates. There were 48 pairs of twins in which 76 infants were appropriate for gestational age (AGA) with birth weights between the 10th and 90th percentile and 20 were small for gestational age (SGA) with birth weights <10th percentiles. Each AGA twin was matched as closely as possible for birth weight to an AGA singleton. Each SGA twin was matched with two cohorts of AGA singletons: one with similar birth weight and one with similar gestation., Results: For AGA twins and their singleton cohort matched for birth weights, profile analysis using repeated measure analysis of variance showed that there were no significant differences in bone, fat and lean mass either as absolute values or as percentage of total weight. This was also the case for body composition of SGA twins compared to singletons matched for birth weight. In contrast, SGA twins have significantly lower absolute amounts of lean with tendency to lower fat and bone mass., Conclusion: For clinically normally grown neonates, with comparable weight, the body composition with respect to bone, fat and lean mass components are similar regardless whether they are products of singleton or twin pregnancies.

Objective: To evaluate the published clinical data on the physiologic effects of using palm oil and its low melting fraction, palm olein (PO) as a dominant lipid source in the fat blend in infant formulas., Design: A systematic search of Medline and the Cochrane Database of Systematic Reviews was performed to retrieve studies comparing infants who received infant formulas containing PO with those who received infant formulas without PO or which contained synthetic triacylglyceride as a source of palmitic acid. Outcomes of interest include intestinal fractional absorption of fat, palmitic acid and calcium; and bone mass. The effect size for each dependent variable in each published study was obtained by standardizing based on the difference in means between non-PO and PO group with respect to the standard deviation of the PO group. Trend analysis of the outcome of interest was performed when 3 or more between group comparisons were available. The comparison of effect size across different studies was based on all available data and includes results that showed no significant difference between infants fed PO or non-PO study formulas in the outcomes of interest., Results: Nine publications were identified with non-PO and PO comparison groups. The gestational ages of infants in the published studies were between 28 to 42 weeks and postnatal ages were birth to 192 days at study onset. Within each published study, there was some variability in the effect size between non-PO and PO groups. The standardized results were consistently significantly (p < 0.05) positive in favor of the feeding with non-PO formulas with respect to increased intestinal fractional absorption of fat, palmitic acid and calcium. The latter two variables were significantly different by at least 0.6 SD. Bone mass measured as total body bone mineral content was significantly higher in the non-PO group by at least 0.3 SD., Conclusion: The use of PO in infant formulas to match the human milk content of palmitic acid has unintended physiological consequences including diminished intestinal absorption of fat, palmitic acid and calcium and lower bone mass. The avoidance of PO or its substitution with synthetic triacylglyceride in infant formulas can prevent this detrimental effect.

African-American women have disturbingly high rates of hypertension, exceeding those of African-American men and other ethnic groups. Reasons for these disparities are not understood. Depression, more common in women than men, has been linked to endothelial dysfunction, inflammation, metabolic and hematologic abnormalities, and increased sympathetic nervous system activity--all factors associated with cardiovascular disease. A descriptive correlational design was used to test the following hypotheses: 1) African-American women with higher levels of depression will have higher blood pressure (BP) levels, more cardiovascular risk factors, greater stress, and lower social support; and 2) depression will mediate the relationship between stress and BP. A convenience sample of 245 hypertensive African-American women (mean age, 61+/-12.7 years) was recruited through free BP screenings offered in the community. All data were collected during a structured interview and brief physical examination. Pearson r correlation coefficients, analysis of variance, and multiple regression analyses were used to analyze the hypotheses. Women with higher levels of depression had higher diastolic BP and were more likely to smoke, eat fewer fruits and vegetables, and have more stress and less social support. Depression mediated the relationship between stress and diastolic BP. The findings emphasize the importance of assessing both behavioral and psychosocial factors in urban African-American women with hypertension.

This study examined the relationship between measured and derived anthropometric measurements with dual-energy X-ray absorptiometry measured lean and fat mass at 3.0 +/- 2.8 (SD) days in 120 neonates with birth weights appropriate (AGA; n=74), large (LGA; n=30); or small (SGA, n=16) for gestational age. Anthropometric measurements, including total body weight and length, and regional measurements, including circumferences of head, chest, abdomen, midarm, and midthigh and dynamic skinfold thickness (15 and 60 s) at tricep, subscapular, suprailiac, and midthigh, were performed. Derived anthropometry included muscle and fat areas, and ratios were calculated from direct measurements. The skinfold thickness measurements between 15 and 60 s were highly correlated (r=0.973-0.996, p <0.001 for all comparisons). Strong correlations existed within the four circumferences of trunk and extremities, the four skinfolds, and the ratios of weight to length and its higher powers. Weight and length accounted for >97% of the variance of lean mass in AGA and SGA infants and 46% of the variance in LGA infants and for 80, 82, and 84% of the variance of fat mass in SGA, AGA, and LGA infants, respectively, whereas midarm:head circumference ratio and arm muscle and fat areas are the most important derived anthropometry in the prediction for body composition. They independently accounted for up to 16.5 and 10.2%, respectively, of the variance in body composition depending on the state of in utero growth. Thus, total body weight and length and some selected regional and derived anthropometry accounted for the vast majority of the variance of body composition.

Background: A piglet model was used to determine the influence of frequently encountered situations in clinical studies of infants and young children on fan-beam dual-energy x-ray absorptiometry (DXA) measurements., Methods: DXA scans of piglets (640 g to 21,100 g) were acquired in the infant and adult mode and were analyzed with 1 infant, 1 pediatric, and 3 versions of adult software., Results: The effect of repositioning of the piglets from the center to the periphery of the scanning table on DXA measurements included an average difference of up to 0.5% for total weight, 5.0% for bone mineral content, 5.6% for bone mineral density, 1.3% for lean mass, and 21.9% for fat mass (< or = .05, all comparisons) although no significant changes occurred when the piglets were scanned in symmetrical positions on either edge of the scanning table. Different posture (prone vs supine and side), varied number of blankets overlaid or wrapped around the piglet, and parenteral but not enteral bolus feeding could significantly alter fan-beam DXA measurements to varying extents. Adult and pediatric software underestimated bone area and bone mineral content but overestimated bone mineral density, lean mass, fat mass, and total weight compared with infant software measurements. However, strong predictive relationships among these fan-beam DXA data in subjects >10 kg allow systematic corrections of data from different scan modes and different software., Conclusions: Attention to details and consistency in the technique for scan acquisition and analysis are critical to the generation of meaningful data and to allow for detection of true differences in DXA measurements of small subjects.

Objective: To document the clinical and experimental situations that may affect DXA measurements in small subjects., Methods: 49 piglets (886g to 21100g) had measurements with either of two pencil beam densitometers (QDR 1000W and QDR 2000 Plus, Hologic Inc, Waltham, MA) using commercial infant (IWB) and adult whole body (AWB) software v5.71p and v5.71 respectively. AWB scans were analyzed with three additional software versions. 35 infants (2115 to 11564g) had IWB measurements., Results: DXA measurements of total weight, bone mineral content, bone area, bone mineral density, fat and lean mass from IWB scans (all piglets) and from AWB scans (piglets >12 kg) were highly reproducible (p < 0.001). A statistically significant change occurred in at least one of the DXA measurements from the use of different platforms, variations in the amount and placement of covering (e.g., blanket), placement of the external calibration standard, presence of radiographic contrast material, presence of movement artifact, delivery of an intravenous fluid bolus prior to scanning or improper delineation of external calibration standard during analysis. Additionally, results varied amongst different versions of software as well as between IWB and AWB softwares., Conclusion: In small subjects, consistency in the DXA techniques is paramount for valid and meaningful comparison of DXA data in bone mass and body composition.

Objective: To validate the most widely reported dual energy X-ray absorptiometry (DXA) technique for the measurement of bone mass and body composition in human infants with a piglet model., Methods: Duplicate scans were obtained in 13 piglets (1950g to 21100g) using a whole body densitometer (Hologic QDR 2000 plus, Hologic Inc., Waltham, MA) operated in the pencil-beam mode on a two platform (aluminum platform overlying a foam table pad) system. DXA measurements that included total weight, bone mineral content, fat and lean mass were compared with carcass weight and chemical analysis for ash and calcium content, fat and lean mass., Results: Measurements from duplicate DXA scans were nearly perfectly correlated (r = 0.98 to 1.00). DXA measurements were strongly predictive of scale weight and chemical composition for all piglets (adjusted r(2) = 0.93 to 1.00, intraclass reliability coefficients = 0.943 to 0.999, p < 0.001 for all comparisons) although DXA bone mineral content consistently underestimated carcass ash and calcium content. Measured values from heavier piglets were not significantly different from values predicted from the lighter piglets' data. Slopes from regression based on lighter versus heavier piglets were not significantly different except for the bone mineral content with carcass ash or calcium content., Conclusion: Our study validated the use of pencil beam DXA and its ability to determine relative changes in bone mass and body composition measurements over a much greater range of body weight than previous reports although its use as a direct indicator of nutrient requirement may be limited.

Background: Fan beam dual energy x-ray absorptiometry (FB DXA) has recently been validated for the measurement of body composition in small subjects. This study represents the first report of body composition (bone mineral content, fat mass, and lean mass) in human neonates measured by FB DXA., Methods: FB DXA measurements were performed in 73 healthy singleton neonates with mean +/- SD birth weights 3354 +/- 316 g (range, 2720 to 3982 g) and gestational ages 39.5 +/- 1.2 weeks (range, 37 to 42 weeks). There were 26 white (11 male infants, 15 female infants), 42 African American (17 male infants, 25 female infants), and 5 Hispanic (4 male infants, 1 female infant) infants. The predictive ability of physiologic parameters to predict body composition measurements was determined with regression analysis., Results: The mean +/- SD for bone mineral content was 89.3 +/- 14.1 g, fat mass was 485 +/- 14.1 g, and lean mass was 2898 +/- 281.5 g. Weight was significantly correlated with all DXA measurements and was the single best predictor of body composition. Weight alone contributed 32% to 98% of the variance of the DXA measured parameters. Gender, race, and length were additional predictors that could be forced into a predictive equation for selected DXA dependent variables according to statistical significance. An independent gender effect was also demonstrated, with male infants having higher lean mass but lower fat mass., Conclusions: Our data in human neonates demonstrated the ability of FB DXA to measure body composition. Body weight is the best physiologic predictor of overall body composition. There is also an independent gender effect on soft tissue body composition.

Objectives: A piglet model was used to validate and cross validate the fan-beam (FB) dual energy X-ray absorptiometry (DXA) software vKH6 and to determine the predictive values of physiologic parameters (weight, length, age and gender) on body composition., Methods: Nineteen piglets (Group A: 600 to 21100 g) were used to validate the FB-DXA measurements of body composition based on chemical analysis of the carcass. An additional 22 piglets (Group B: 640 g to 17660 g) had FB-DXA measurements, and these values were compared to the predicted values generated from regression equations computed from group A piglets. Body composition for bone mass, lean mass and fat mass was based on ash weight, nitrogen and fat measured from three aliquots of homogenate from each carcass. Data from all piglets (n = 41) were used to determine the variations in body composition. Data analysis used regression, t test and analysis of variance., Results: Duplicate DXA (total weight TW, bone mineral content BMC, bone area BA, bone mineral density BMD, lean mass LM and fat mass FM) measurements were highly correlated (r = 0.98 to 1.00, p < 0.001 for all comparisons) and were not significantly different. No significant differences were found in the residuals from predicted versus measured DXA values between the larger and the smaller (<1.6 kg) piglets from Group A. For Group B piglets, the DXA measured TW of 5666 +/- 5692 g (mean +/- SD), LM (5063 +/- 5048 g), FM (465 +/- 510 g), BMC (138 +/- 139 g), BA (486 +/- 365 cm(2)) and BMD (0.235 +/- 0.071 g/cm(2)) were highly significantly correlated with (r = 0.94 to 1.00, p < 0.001 for all comparisons) and were not significantly different from the predicted values. Data from all piglets (n = 41) showed that weight is the dominant predictor of whole body and regional body composition. Length, age or gender contributed to <2% of the variability of body composition., Conclusion: Body composition measurements using the FB DXA software vKH6 is highly reproducible. The software vKH6 is validated for use in a wide range of body weights and body composition, and cross-validated using a separate group of animals. Body weight is the dominant predictor of body composition in immature piglets.

Background: Compared with the older pencil-beam (PB) dual-energy X-ray absorptiometry (DXA), the newer fan-beam (FB) DXA has the advantage of faster scan acquisition and greater accuracy of body-composition measurement in small subjects. However, no data exist on the relation between the measurements obtained with these techniques., Objective: The objective of the study was to investigate whether PB and FB DXA measurements in small subjects are interchangeable., Design: PB and FB DXA scans were performed on 26 piglets and 54 infants to examine the relation between the measurements obtained by using the 2 techniques., Results: The correlation between all PB and FB DXA measurements of variables (total weight, bone area, bone mineral content, bone mineral density, and lean and fat masses) approached 1.0, but there were significant differences in absolute values. The extent of the differences varied according to the variable, with the lowest value for total weight (mean difference: approximately 1% for both piglets and infants) and the highest value for bone mineral content (mean difference: 35.3% and 36.7% for piglets and infants, respectively). PB and FB DXA measurements were strongly predictive of each other after adjustment (r(2) = 0.927-1.000 for the piglet data and 0.939-0.999 for the infant data)., Conclusion: In small subjects, DXA measurements from PB and FB techniques were strongly predictive of each other, although their absolute values differed. Thus, group comparison of PB and FB DXA data is possible after adjustment of the data from either technique. It is advisable to generate normative data for each technique and to use the same technique throughout longitudinal studies.

Objective: To test the suitability of phantoms to cross-calibrate body composition measurements in small subjects among different dual energy X-ray absorptiometry (DXA) instruments., Methods: A set of four phantoms with total weights 1520g, 3140g, 4650g and 7490g were made with low cost and easily available materials. Each phantom was made from assembling polyethylene bottles (100 to 1000 mL) filled with either pure olive oil or electrolyte solution in different combinations, and borosilicate tubes (3 and 5 mL) and flexible polypropylene tubing filled with calcium carbonate. Triplicate measurements of each of the four phantoms were performed with three pencil beam densitometers made by the same manufacturer (Hologic Inc., Waltham, MA): two QDR 2000 (University of Liege, Liege, Belgium, and Wayne State University, Detroit, Michigan) and a QDR1500 (University Children's Hospital, Greifswald, Germany) using infant whole body-scanning mode and analyzed with software V5.73P., Results: DXA measured total weight, or bone, lean and fat masses, from one center were highly predictive of DXA measurements from the other centers with an adjusted r2 of 0.94 to 1.00, p < 0.001. This was the case whether the measurements from single scan or from average of triplicate scans were used in the analysis., Conclusions: Systematic corrections, in the form of linear transformations, are possible to allow comparison of clinical data generated from different centers. Different size phantoms can be made to accommodate the varying range of weights and body composition of study subjects.

The objectives of this study were to do inexpensive lamellar body count (LBC) in amniotic fluid, to do statistical analysis to evaluate cutoff values for fetal lung maturity (FLM) and fetal lung immaturity (FLI), to derive a threshold for obtaining a lecithin-to-sphingomyelin (L/S) ratio and phosphatidylglycerol percentage (%PG), and to determine the potential cost savings to the hospital if they use this new method. Testing (LBC, L/S ratio, and %PG) was done on 123 specimens of amniotic fluid. Receiver operating characteristic (ROC) curve, discriminant, linear regression, chi2, and cost analyses were used to evaluate the laboratory and financial parameters. Lamellar body counts of greater than 41,500 (Coulter MAXM: sensitivity, 90.5%; specificity, 87.7%; positive predictive value, 79.2%; negative predictive value, 94.7%) and greater than 32,000 (Coulter Gen.S: sensitivity, 90.5%; specificity, 85.2%; positive predictive value, 76.0%; negative predictive value, 94.5%) were the best threshold for biochemical FLM. Similarly, LBC of less than 24,000 (MAXM: sensitivity, 78.6%; specificity, 100%; positive predictive value, 100%; negative predictive value, 90.0%) and less than 21,000 (Gen.S: sensitivity, 71.4%; specificity, 100%; positive predictive value, 100%; negative predictive value, 87.1%) provided the best statistical cutoff for biochemical FLI from discriminant analysis. The authors concluded that FLM and FLI can be predicted with reasonable accuracy from LBC in amniotic fluid specimens. The expensive and not easily accessible L/S ratio and %PG can then be done only in cases in which LBC indicates transitional FLM. A cascade approach results in 86% savings to the hospital if the L/S ratio and %PG are not sent to a reference laboratory.

A piglet model was used to determine whether the fan beam dual energy X-ray absorptiometry technique (DXA) could be adapted for the measurement of body composition of small subjects. Commercial domestic swine piglets (n = 14) with weights between 1.95 and 21.1 kg had duplicate fan beam-DXA scans followed by chemical analysis of body composition. Each scan required 2-3 min to complete. DXA-measured total body weight was validated against scale weights of the piglets (with and without blanket and other covering), DXA bone mineral content validated against carcass ash and calcium, and DXA lean and fat mass validated against chemical lean and fat contents. Measurements from duplicate DXA scans were highly reproducible with adjusted r(2) values from 0.992 to 1.000. Each DXA measurement was highly predictive of the scale weight or specific chemical body composition with adjusted r(2) values from 0.974 to 0.999. The intraclass reliability coefficient among measurements from individual scans with scale weight or the weight of individual chemical components was extremely high at > or =0.99 for all comparisons. The SD of residuals for DXA prediction of scale weights (with and without covering) were 168 and 157 g, respectively, and were 27, 8.8, 122 and 72 g for the prediction of carcass ash, calcium, lean and fat tissue content, respectively. We conclude that rapid scan acquisition, accurate and precise prediction of scale weight and components of body composition would support the use of fan beam-DXA for body composition studies in growing humans or animals.

Objective: The objective was to compare dual-energy x-ray absorptiometry-measured body composition between large (LGA) and appropriate (AGA) birth weight for gestational age neonates., Study Design: LGA term infants (n = 47) with birth weights > or =4000 g were compared with 47 gestational age-matched AGA infants; 11 LGA infants were born to mothers with gestational (9) or pregestational diabetes (2). Dual-energy x-ray absorptiometry scans were performed at 1.8 +/- 1.0 days after birth., Results: Body weight and length were the dominant predictors of body composition in LGA and AGA neonates. However, LGA neonates had significantly (P <.001, all comparisons) higher absolute amounts of total body fat, lean body mass, and bone mineral content and had significantly (P <.001, all comparisons) higher proportions of total body fat and bone mineral content but lower lean body mass as a percent of body weight. The changes for total body fat and lean body mass as a percent of body weight were greatest (P <.001) in LGA infants whose mothers had impaired glucose tolerance., Conclusion: LGA neonates have higher body fat and lower lean body mass than AGA infants. Impaired maternal glucose tolerance exaggerated these body composition changes.

Dual energy x-ray absorptiometry (DXA) of the lumbar spine (LS) was measured in 201 singleton infants with birth weights from 1152 to 3970 g and gestational ages from 27 to 42 wk. All infants were well and studied at a mean (+/-SD) of 2.1 (+/-1.6) days after birth. There were 75 Caucasian (46 males, 29 females) and 126 African American infants (58 males, 68 females). Scan acquisition of the first to fourth lumbar vertebrae was performed with a single beam whole body scanner (Hologic QDR 1000/W densitometer, Hologic Inc, Waltham, MA, U.S.A.) using the infant spine mode. Scan analysis was performed with software version 4.57Q and consistent region of interest. The SD of difference for duplicate LS scans is <1.4% at a mean bone mineral content (BMC) of 2.14 g. Results show that LS BMC, area, bone mineral density (BMD) increased by approximately 550%, 280% and 180%, respectively, between 27 and 42 wk gestational age. Body mass accounted for about 70% and 55% of the variance in BMC and BMD respectively. In contrast, the infant's length appears to be the best determinant of LS area and accounts for about 75% of the variance in LS area. Race, gender or season has little or no effect on LS bone mass. There was progressive increase in BMC and area from first to fourth lumbar vertebra but BMD was significantly higher only at the fourth lumbar vertebra. We conclude that DXA LS can be performed even in small preterm infants. Its excellent precision, low radiation exposure and rapid scan acquisition offers promise as a useful tool for widespread use in pediatrics. Our data may be used as a basis for further studies in physiologic and pathologic situations that may affect bone mineralization in infants.

The predictive values of anthropometric measurements, race, gender, gestational and postnatal ages, and season at birth and at study for the total body dual energy X-ray absorptiometry (DXA)-derived lean mass (LM), fat mass (FM) and fat mass as a percentage of body weight (%FM) were determined in 214 singleton appropriate birth weight for gestational age infants [101 Caucasian (60 boys, 41 girls) and 113 African American (55 boys, 58 girls)]. Gestational ages were 27-42 wk and the infants were studied between birth and 391 d, weighing between 851 and 13446 g. In addition, predictive value of body weight, LM and FM for DXA bone measurements was also determined. Scan acquisition used Hologic QDR 1000/W densitometer and infant platform and scans without significant movement artifacts were analyzed using software 5.64p. Body weight, length, gender and postnatal age were significant predictors of LM (adjusted R:(2) >0. 94) and FM (adjusted R:(2) >0.85). Physiologic variables had little predictive value for %FM except in the newborns (adjusted R:(2) 0. 69). Body weight was the dominant predictor of LM and FM, although length had similar predictive value for LM with increasing postnatal age. Female infants had less LM and more FM throughout infancy (P: < 0.01). LM or FM offered no advantage over body weight in the prediction of bone mass measurements. DXA is a useful means with which to determine body composition, and our data are important in the design and assessment of nutritional intervention studies.

This article describes the sensitivity and specificity of troponin I when compared to creatine kinase-MB (CK-MB) and electrocardiography (ECG) for diagnosing acute myocardial infarction (AMI). Two different lower levels for defining positive results with troponin I were evaluated. A retrospective study of 153 patients who presented to the emergency department of a community hospital supplied the pool of patients for this study. Patients included in this study were those for whom a CK-MB was ordered. The majority of these patients were evaluated for chest pain or symptoms suggesting an acute cardiac event. Of the 153 patients studied, CK-MB results were positive in 91 (59%) patients; ECG revealed AMI in 72 (47%) patients. There were 103 (67%) patients who had either positive CK-MB or ECG results. Ninety (59%) patients had a troponin I level greater than 2.0 ng/mL, and 18 (12%) patients had a troponin I level between 0.6 and 2.0 ng/mL. Seven patients whose troponin I level was between 0.6 and 2.0 ng/mL had negative CK-MB and ECG results. Therefore, 11 patients with troponin I between 0.6 and 2.0 ng/mL had AMI. Five patients with positive troponin I results (> 2.0 ng/mL) had negative CK-MB and ECG results. When a troponin I level greater than 0.6 ng/mL was used as a positive value, compared to CK-MB and ECG using either time zero or time 6 hours, the sensitivity was 94% and specificity was 81%. When troponin I greater than 2.0 ng/mL was used to define a positive test, the sensitivity was 85% and specificity was 91% when compared to CK-MB and ECG.

The Well-Being Institute (WBI), a community-based nursing organization in Detroit, Michigan, has developed and put into practice innovative intervention and service delivery models to assist HIV-positive women who have a history of substance abuse and mental illness. These multiple-diagnosed women are known to have special problems and barriers to accessing health care. The service delivery model is based on "hyperlinking" women into hard-to-get health care appointment slots through nurses' personal contacts in health care clinics. The intervention model is the personalized nursing LIGHT model. This article describes the service delivery and intervention models and discusses outcomes of the WBI Women's Intervention Program in practice. The program locates HIV-positive, substance-abusing women; enrolls them in primary medical and mental health care; and helps retain them in health care. The results of the model in practice demonstrate its success in hyperlinking hard-to-reach and hard-to-serve HIV-positive women with health care and other needed services and resources. In addition, these multiple-diagnosed women have shown positive effects with respect to improved sense of well-being and decreased psychosocial distress.

The study described here examined the prevalence of HIV infection as a function of place of residence and high-risk behaviors in six subpopulations of out-of-treatment drug injectors and crack cocaine users who participated in the National Institute on Drug Abuse (NIDA) Cooperative Agreement project. The subpopulations were blacks, Hispanics, and non-Hispanic whites sampled separately by gender. The research asked three questions: (a) Is the HIV infection rate higher among the on-the-street homeless than among those in other places of residence? (b) Do high-risk drug-related behaviors differ by housing status? and (c) What are the joint effects of high-risk drug-related behaviors and housing status on the probability of HIV infection? Overall, on-the-street homeless had a significantly higher HIV+ rate (19.0%) than the study population as a whole (11.2%). Rates differed by gender and race, with exceptionally high HIV+ rates for on-the-street homeless Hispanic males (29%) and females (32%) and for on-the-street homeless black females (38%). Having used drug works previously used by a HIV-infected person was a strong predictor of HIV+ status, as was frequency of drug injections and crack use. Having multiple sex partners was also a significant risk behavior. Findings argue against considering on-the-street homelessness as equivalent to shelter dwelling or aggregated homelessness for purposes of the AIDS epidemic. On-the-street homeless drug users were at strong risk for acquisition and transmission of HIV infection and therefore in need of targeted-racially relevant, ethnically relevant, and gender-relevant-public health interventions to help prevent the spread of AIDS.

Controversy persists regarding the validity, utility, and practicality of oral examinations. This study of a recent 3-year experience at the University of Michigan Medical School was undertaken to determine the value of the oral examination in the required junior year surgery clerkship. Multiple regression analysis of the relationship between the oral examination and ward grades, written examination grades, and the final grades for the clerkship years 1980 to 1981 (n = 198), 1981 to 1982 (n = 234), and 1982 to 1983 (n = 215) (classes of 1982, 1983, and 1984) revealed significant correlation between the oral examination and other evaluation parameters. Stepwise regression analysis revealed that the oral examination contributed unique information to final grade determination. Two surveys identified faculty and student opinion regarding the oral examination. The results were consistent during the 3-year period of study. Faculty and student opinion regarding the examination as an evaluation process and motivational device were positive, as was opinion regarding the breadth and depth of knowledge tested and the examination as a learning experience and an accurate reflection of students' performance. Both faculty and students agreed that the examination was worth the time and effort invested by faculty, was an appropriate evaluation process, and was a source of worthwhile faculty and student interaction.