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Background End-of-life cancer care involves multidisciplinary teams working in various settings. Evaluating the quality of care and the feedback from such processes is an important aspect of health care quality improvement. Our retrospective cohort study reviewed health care use by lung cancer patients at end of life, their reasons for visiting the emergency department (ed), and feedback from regional health care professionals. Methods We assessed 162 Ontario patients with small-cell and relapsed or advanced non-small-cell lung cancer. Demographics, disease characteristics, and resource use were collected, and the consenting caregivers for patients with ed visits were interviewed. Study results were disseminated, and feedback about barriers to care was sought. Results Median patient age was 69 years; 73% of the group had non-small-cell lung cancer; and 39% and 69% had received chemotherapy and radiation therapy respectively. Median overall survival was 5.6 months. In the last 3 months of life, 93% of the study patients had visited an oncologist, 67% had telephoned their oncology team, 86% had received homecare, and 73% had visited the ed. Death occurred for 55% of the patients in hospital; 23%, at home; and 22%, in hospice. Goals of care had been documented for 68% of the patients. Homecare for longer than 3 months was associated with fewer ed visits (80.3% vs. 62.1%, p = 0.022). Key themes from stakeholders included the need for more resources and for effective communication between care teams. Conclusions Use of acute-care services and rates of death in an acute-care facility are both high for lung cancer patients approaching end of life. In our study, interprofessional and patient–provider communication, earlier connection to homecare services, and improved access to community care were highlighted as having the potential to lower the need for acute-care resources. [ABSTRACT FROM AUTHOR]

To assess the possibility of ethnic differences in mineral metabolism in prepubertal children, we compared measures of calcium metabolism in 7- and 8-y-old Mexican-American (MA) and non-Hispanic Caucasian (CAU) girls (n = 38) living in southeastern Texas. We found similar fractional calcium absorption, urinary calcium excretion, calcium kinetic values and total-body bone mineral content in the MA and CAU girls. In contrast, parathyroid hormone (PTH) concentrations were greater in MA girls (4.01 +/- 0.47 vs. 1. 96 +/- 0.50 pmol/L, P = 0.005) than in CAU girls. Serum 25-hydroxyvitamin D concentrations were lower in MA girls (68.9 +/- 7.7 vs. 109.4 +/- 8.4 nmol/L, P = 0.001) than in CAU girls, but 1, 25-dihydroxyvitamin D concentrations did not differ between groups. Seasonal variability was seen for 25-hydroxyvitamin D concentrations in girls of both ethnic groups, but values in all of the girls were >30 nmol/L (12 ng/mL). We conclude the following: 1) greater PTH levels in MA girls than CAU girls are present without evidence of vitamin D deficiency; and 2) differences in 25-hydroxyvitamin D and PTH concentrations between MA and CAU girls do not have a large effect on calcium absorption, excretion or bone calcium kinetics. These data do not provide evidence for adjusting dietary recommendations for mineral or vitamin D intake by MA girls. [ABSTRACT FROM AUTHOR]

Background: Heritability estimates for body mass index (BMI; in kg/m(2)) in children generally have been derived from twin and adoption studies. However, BMI does not reflect total or regional body composition., Objective: We evaluated the familial resemblance of body composition between prepubertal girls of normal weight and body fatness and their parents by using state-of-the-art technology., Design: The subjects were 101 girls [mean age: 8.5 +/- 0.4 y; percentage body fat (%BF): 12-30%] and their biological parents. Weight, height, and body composition [fat mass (FM), fat-free mass (FFM), and %BF] were measured with dual-energy X-ray absorptiometry (DXA) and total body potassium (TBK)., Results: Weight, height, and BMI showed low-to-moderate similarity between the girls and both their parents (r = 0.29-0.44, P < 0.01). The girls' FM, FFM, and %BF were significantly related to both parents' body composition. Cross-generational equations were developed for DXA, eg, child's %BF = 12.4 + (0.158 paternal %BF) + (0.145 maternal %BF) (adjusted r(2) = 0.16, P < 0.001). Regional analysis with DXA showed that the adjusted r(2) values for the arm, trunk, and leg regions, respectively, were 0.17, 0.33, and 0.31 for lean tissue mass and 0.11, 0.14, and 0.09 for FM. TBK showed a similar relation between parents and girls (r = 0.28-0.47, P < 0.01). Significant heritability (h(2) +/- SE) was detected for BMI (0.35 +/- 0.17, P = 0.03) and %BF measured with DXA (0.50 +/- 0.12, P = 0.0001)., Conclusion: The body composition of prepubertal girls of normal weight and body fatness is significantly related to the body composition of both biological parents.

The objective of this study was to develop an anthropometry-based prediction model for the assessment of bone mineral content (BMC) in children. Dual-energy X-ray absorptiometry (DXA) was used to measure whole-body BMC in a heterogeneous cohort of 982 healthy children, aged 5-18 years, from three ethnic groups (407 European- American [EA], 285 black, and 290 Mexican-American [MA]). The best model was based on log transformations of BMC and height, adjusted for age, gender, and ethnicity. The mean +/- SD for the measured/predicted in ratio was 1.000 +/- 0.017 for the calibration population. The model was verified in a second independent group of 588 healthy children (measured/predicted In ratio = 1.000 +/- 0.018). For clinical use, the ratio values were converted to a standardized Z score scale. The whole-body BMC status of 106 children with various diseases (42 cystic fibrosis [CF], 29 juvenile dermatomyositis [JDM], 15 liver disease [LD], 6 Rett syndrome [RS], and 14 human immunodeficiency virus [HIV]) was evaluated. Thirty-nine patients had Z scores less than -1.5, which suggest low bone mineral mass. Furthermore, 22 of these patients had severe abnormalities as indicated by Z scores less than -2.5. These preliminary findings indicate that the prediction model should prove useful in determining potential bone mineral deficits in individual pediatric patients.

This article provides an overview of the present status of in vivo body composition methodologies that have potential for use in field studies. The methods are divided into four general categories: anthropometric indices and skinfold, body volume measurements, body water measurements including bioelectrical methods, and imaging techniques. Among the newest technologies are air-displacement plethysmography, three-dimensional photonic scanning, multifrequency bioelectrical impedance spectroscopy and whole-body tomography using electrical impedance and magnetic induction. These newer approaches are compared with the established reference methods. The advantages and limitations of each technique as a field method are presented relative to the corresponding concepts of an ideal method.

Background: Early diagnostic efforts and advances in multidrug therapy have considerably prolonged the survival time of children infected perinatally with HIV. Despite these advances, few studies have addressed calcium status and bone growth in HIV-infected children., Objective: Our objective was to examine the effect of HIV infection on calcium status and bone growth in children., Design: We measured calcitropic hormones, urinary calcium excretion, bone mineral content, and body composition in 19 young girls aged 9.2 +/- 2.6 y (range: 5.9-15.2 y) who were infected perinatally with HIV., Results: Serum concentrations of 1,25-dihydroxyvitamin D [1,25(OH)(2)D] and parathyroid hormone concentrations were elevated above normal ranges in 25% and 12% of these girls, respectively. Urinary calcium excretion normalized for creatinine excretion was also elevated (Ca/Cr >0.18) in 17% of these children despite suboptimal calcium intakes (679 +/- 437 mg/d). Total-body bone mineral content, measured with the use of dual-energy X-ray absorptiometry, averaged 845.1 +/- 279.0 g and was on average 2.7 z scores below age- and race-matched values reported in non-HIV-infected healthy girls. Significant positive correlations were found between an indirect marker of bone resorption in urine (N:-telopeptide) and 1,25(OH)2D (P < 0.02, r2 = 0.586, n = 9), and between serum N-telopeptide and total alkaline phosphatase (P < 0.001, r2 = 0.541, n = 17), suggesting that calcium insufficiency may be increasing bone resorption in this group., Conclusions: Young girls with HIV infection had low bone mass and evidence of calcium insufficiency. Nutritional counseling of children with HIV infection should emphasize adequate calcium intakes because of the importance of this age period in bone mineral acquisition.

We compared the effects of supplementing either animal plasma or extruded soy protein in the diet based on the efficiency of dietary protein utilization for lean tissue growth in early-weaned pigs. Twenty-four 14-d-old pigs (4 kg body weight) were pair-fed (per kg body weight) either a control diet containing extruded soy protein (C; n = 12) or a diet with 10% animal plasma (P; n = 12) for 24 d. During the 24 days, protein intake was not different, yet mean daily body weight gains (+23%) and food conversion efficiencies (expressed as the ratio of body weight gain to protein intake) (+19%) were greater (P < 0.05) in the P group than in the C group. Lean body mass measured after 24 d, using both dual-energy X-ray absorptiometry and total body potassium analysis, was significantly (P < 0.05) greater (approximately 16%) in P than in C pigs. The circulating urea concentrations were 40% lower (P < 0.05) in P than in C pigs. Our results demonstrate that supplementing early-weaned pig diets with animal plasma rather than extruded soy protein increased the efficiency of dietary protein use for lean tissue growth and that this response is mediated in part by decreased amino acid catabolism.

Background: Although skinfold-thickness equations are widely used to estimate body fat, their accuracy in a biracial population of female adolescents has not been established., Objective: We undertook this study to determine the agreement between 8 widely used skinfold-thickness equations and a 4-compartment criterion model in predicting the percentage body fat of 72 white and 40 African American girls aged 13.0 +/- 1.9 y., Design: The biceps, triceps, suprailiac, subscapular, thigh, calf, and abdominal skinfold thicknesses of the subjects were measured with skinfold calipers and the buttocks circumference with a metal tape. The percentage fat mass (%FM) predicted by using each skinfold-thickness equation was compared with the criterion value calculated by the 4-compartment model on the basis of measurements of body density, body water, and bone mineral content., Results: When the racial groups were analyzed separately, the Bland-Altman analysis indicated that the quadratic equations agreed most closely with the 4-compartment model's measurement of %FM. Agreement of the other equations varied with body fatness., Conclusions: The quadratic equation of Slaughter et al is recommended for population studies in female adolescents because of its accuracy and simplicity. However, an individual %FM can be over- or underestimated by approximately 10% when this skinfold-thickness equation is used.

Normative body composition during the first 2 y of life was derived from a prospective study of 76 children. We present 1) fat free mass (FFM) and its components, and fat mass (FM), 2) incremental growth rates partitioned into chemical components, and 3) age-specific and gender-specific constants for converting chemical and physical components into FFM for children during the first 2 y of life. A multicomponent model based on measurements of total body water (TBW), total body potassium (TBK) and bone mineral content (BMC) was used to estimate FFM and FM at 0.5, 3, 6, 9, 12, 18, and 24 mo of age. TBW was determined by deuterium dilution, TBK by whole body counting, and BMC by dual energy x-ray absorptiometry. FFM was higher in boys than girls between 0.5-18 mo of age (p < or = 0.05). Percent FM increased on average from 13 to 31% between 0.5 and 3-6 mo, and then gradually declined. Percent FM was significantly higher in girls than in boys at 6 and 9 mo of age (p < or = 0.02). The components of FFM on a percentage basis changed with age (p = 0.001), but not gender. The protein content of FFM increased gradually with age, while TBW declined (p = 0.001). As a percentage of FFM, osseous mineral increased from 2.0 to 3.4% in boys and from 2.1 to 3.3% in girls between 0.5 and 24 mo (p = 0.001). Density and potassium content of FFM increased gradually with age (p = 0.001). These normative body composition data provide an updated reference upon which to assess normal growth and nutritional status of pediatric populations representative of mixed feeding groups during the first 2 y of life.

In vivo methods used to study human body composition continue to be developed, along with more advanced reference models that utilize the information obtained with these technologies. Some methods are well established, with a strong physiological basis for their measurement, whereas others are much more indirect. This review has been structured from the methodological point of view to help the reader understand what can be examined with each technique. The associations between the various in vivo methods (densitometry, dilution, bioelectrical impedance and conductance, whole body counting, neutron activation, X-ray absorptiometry, computer tomography, and magnetic resonance imaging) and the five-level multicompartment model of body composition are described, along with the limitations and advantages of each method. This review also provides an overview of the present status of this field of research in human biology, including examples of reference body composition data for infants, children, adolescents, and adults.

Background: Bioelectrical impedance spectroscopy (BIS) may provide a noninvasive, rapid method for the assessment of total body water (TBW), extracellular water (ECW), and intracellular water (ICW). Few studies, however, have examined the accuracy of BIS in pediatric populations., Objective: Our objective was to evaluate the accuracy of BIS for the measurement of TBW, ECW, and ICW in healthy children., Design: Dual-energy X-ray absorptiometry (DXA), total body potassium (TBK), and BIS measurements were performed in 347 children (202 males and 145 females aged 4-18 y). The reference values for TBW, ECW, and ICW were defined by using a DXA+TBK model. BIS values were evaluated by using the method of Bland and Altman. A randomly selected calibration group (n = 231) was used to derive new BIS constants that were tested in the remaining group (n = 116)., Results: BIS values were highly correlated with the reference values (r(2) = 0.94-0.97, P < 0.0001), but differences between the BIS and DXA+TBK models for individuals were significant (P < 0.001). Use of new BIS constants reduced the mean differences between the BIS and DXA+TBK models; the SDs of the mean differences were improved (1.8 L for TBW, 1.4 L for ICW, and 1.0 L for ECW) for the total population., Conclusions: On a population basis, BIS can be calibrated to replace the DXA+TBK model for the assessment of TBW, ECW, and ICW in healthy children. The accuracy of the BIS measurement in individual children may be refined further by using age- and sex-specific adjustments for the BIS calibration constants.

The vitamin D receptor (VDR) gene has been implicated as one of the major genetic components of osteoporosis. We evaluated the relationship between markers of mineral status and restriction fragment length polymorphisms of the VDR gene in 72 healthy children age 7-12 years. Using stable isotope techniques and dual-energy X-ray absorptiometry, we measured dietary calcium absorption, bone calcium deposition rates, and total body bone mineral density (BMD). The Fok1 polymorphism at the VDR translation initiation site was significantly associated with BMD (p = 0.02) and calcium absorption (p = 0.04). Children who were FF homozygotes had a mean calcium absorption that was 41.5% greater than those who were ff homozygotes and 17% greater absorption than Ff heterozygotes. BMD was 8.2% greater in the FF genotype than the ff genotype and 4.8% higher than the Ff genotype. These results suggest a substantial relationship between the VDR gene and bone metabolism at one or more levels, including dietary absorption of calcium and BMD in growing children.

Pencil-beam dual-energy X-ray absorptiometers (DXA) are being replaced with instruments that rely solely on fan-beam technology. However, information has been lacking regarding the translation of bone mineral and body composition data between the two devices. We have compared total body scans using pencil-beam (Hologic QDR-2000W) and fan-beam (Hologic QDR-4500A) instruments for 33 children (ages 3-18 years) and 14 adults. Bone mineral content (BMC), bone mineral density (BMD), fat, lean, and body fatness (%fat) values were highly correlated (r2 = 0.984-0.998) between the two DXA instruments. The mean differences between the paired measurements were: deltaBMC = 7.5 +/- 73.6 g, deltaBMD = 0.0074 +/- 0.0252 g/cm2, delta lean = 1.05 +/- 1.8 kg, delta fat = -0.77 +/- 1.7 kg, and delta%fat = -0.94% +/- 2.5%. The BMC and BMD values were not statistically different, whereas the differences for the body composition values were significant (p < 0.02-0.005). Regression equations are provided for conversion of bone and body composition data between pencil-beam and fan-beam values for the whole body. To test the performance of these equations for a second group (23 subjects), predicted values were compared with the measured data obtained using the fan-beam instrument. The mean differences were -1.0% to 1.4%, except for body fat mass, where the difference was 6.4%. For cross-sectional studies, the two DXA technologies can be considered equivalent after using the translational equations provided. For longitudinal studies in which small changes in body composition for the individual are to be detected, we recommend that the same DXA instrument be used whenever possible. For example, transition from a pencil-beam to a fan-beam instrument could, in extreme cases, result in differences as large as 19% for the estimate of body fat mass.

The traditional method of assessing total body water (TBW), extracellular water (ECW), and intracellular water (ICW) has been the use of isotopes, on the basis of the dilution principle. Although the development of bioelectrical impedance techniques has eliminated many of the measurement constraints associated with the dilution methods, the degree of interchangeability between the two methods remains uncertain. We used multifrequency bioelectrical impedance spectroscopy (BIS), 2H2O dilution, and bromine dilution to assess TBW, ECW, and ICW in 469 healthy subjects (248 males, 221 females) aged 3-29 yr. We found that the TBW, ECW, and ICW estimates for the BIS and dilution methods were significantly correlated (r2 = 0.80-0.96, P < 0.0001, SE of the estimate = 2.3-2.7 liters). On the basis of population, the constants used in the BIS analysis could be adjusted so that the mean differences with the dilution methods would become zero. The SD values for the mean differences between the dilution and BIS methods, however, remained significant for both males and females: TBW (+/-2.1-2.8 liters), ECW (+/-1.4-1.6 liters), and ICW (2.0-3.1 liters). To improve the accuracy of the BIS measurement for an individual within the age range we have examined, further refinement of the constants used in the BIS analysis is needed.

Heredity and environmental factors contribute to the development of osteoporosis. Because calcium is the major mineral in bone and adolescence is a key period in bone acquisition, we hypothesized that bone turnover would be less responsive to alterations in dietary calcium intake in both girls and adult women from families with histories of osteoporosis. To address this issue, we studied calcium kinetics in the maternal grandmother (age range 56-81 years), mother (age range 32-47 years), and granddaughter (age range 8-15 years) in 10 multigenerational families. In five families, the mother and/or grandmother had osteoporosis (bone mineral density > or = 2 SD below the age-specific mean). To examine both active and passive calcium absorption, families consumed low- (279 +/- 64 mg/day) and high- (1580 +/- 385) calcium diets for 10 days prior to administration of oral (46Ca) and intravenous (42Ca) stable isotopes. Using repeated measures analysis of variance, fractional calcium absorption, true calcium absorption, bone calcium deposition, and the balance in bone calcium turnover were all significantly affected by diet (p < 0.01). Females from nonosteoporotic families had decreased bone calcium resorption with little change in bone calcium deposition during the high-calcium study. In contrast, girls and adult women from osteoporotic families had increased both bone calcium deposition and resorption during the high-calcium period, leading to a less positive balance in bone calcium turnover. A significant interaction between bone status and diet was found for bone calcium resorption (p < 0.05) and approached significance for bone calcium deposition (p < 0.07), effects which were independent of generation. We conclude that girls and women from osteoporotic families have a significantly altered bone turnover response to acute changes in calcium intake.

To determine whether the lean body mass of well-nourished women was mobilized to support milk protein output during lactation, the body composition of 10 lactating and 10 nonlactating women was examined longitudinally at 6-wk intervals between 6 and 24 wk postpartum and at 52 wk postpartum, and that of 10 nulliparous women was examined at equivalent intervals, by using clinical anthropometry and whole-body potassium counting. Milk production was determined at 6-wk intervals during the period of exclusive breast-feeding (6-24 wk postpartum) by the test-weighing procedure. Milk composition was determined by chemical analysis. Dietary intakes were determined at 6-wk intervals between 6 and 24 wk postpartum from 3-d food records with use of a nutrient database. Lean body mass was maintained in women who exclusively breast-fed their infants during the first 6 mo postpartum while consuming dietary protein in amounts that exceeded those of their nonlactating counterparts by 55%. The high protein intakes were sustained throughout lactation despite a progressive reduction by 32% of milk protein output. Lean body mass was preserved throughout lactation in well-nourished women, suggesting that the metabolic needs of milk protein production were met solely by higher protein intakes of the lactating women.

The study objective was to establish the range of total body-composition values for a young, multiethnic, healthy male population (aged 3-18 y) by using dual-energy X-ray absorptiometry (DXA). Results for 297 males in three ethnic groups [European American (white), n = 145; African American (black), n = 78; and Mexican American (Hispanic), n = 74] are reported. Bone mineral content (BMC), lean tissue mass (LTM), body fat mass, and percentage fat are presented as functions of age. Analysis of variance with age, weight, and height as covariates was used to evaluate differences among the three ethnic groups. BMC and LTM were higher in black than in white males, but no difference in BMC or LTM was evident between the white and Hispanic groups. The relation between total-body BMC and LTM was linear (r = 0.985, P < 0.0001) and independent of age or ethnic classification. The Hispanic males had higher body fat values than the white group, whereas the black males generally had lower values than the white group. When adjusted for body size, the Hispanic males continued to have significantly higher body fat and percentage fat than the white or black males. Ethnic-specific equations for the prediction of body composition as a function of age, weight, and height were derived. The results for the white males in the present study were compared with DXA-derived reference data reported in other countries for young white males. We conclude that reference values of total body composition for young healthy males need to be ethnic specific.

Leptin, a hormone secreted by adipocytes, is elevated in blood of obese adults. It is unknown whether the concentration is affected by gender, ethnicity, age, or stage of sexual maturation in children. We measured serum leptin levels in 183 children and 27 young adults using a double-antibody ELISA assay. Body fat mass (FM) and percent body fatness (%Fat) were determined by dual-energy x-ray absorptiometry. Correlations for serum leptin with FM, %Fat, and a body mass index were examined. Analyses of covariance were used to determine the effects of gender, ethnicity, and sexual maturation (Tanner stage). We found strong positive correlations (r = 0.56-0.88, p < 0.001) for serum leptin with body mass index. %Fat, and FM, which were gender-dependent (p < 0.001), but unaffected by ethnicity. At each Tanner stage, female subjects had higher serum leptin than male subjects (p < 0.001), and this difference remained significant (p < 0.001) when leptin was normalized for FM. For each gender, the mean leptin/FM ratios were relatively invariant during sexual maturation and no differences were observed between the oldest children (Tanner stage 5) and the young adults. The observation that female subjects have higher mean serum leptin and leptin/FM levels than male subjects at prepubertal ages may suggest that there are gender differences in leptin synthesis, clearance rates, bioactivity, and/or leptin transport.

The study objective was to establish the range of body-composition values for a multiethnic female population (aged 3-18 y) by using dual-energy X-ray absorptiometry (DXA). Results for 313 females in three ethnic groups [European American (white), n = 141; African American (black), n = 104; and Mexican American (Hispanic), n = 68] are reported. Changes in the bone mineral content (BMC), lean tissue mass (LTM), fat mass, and percentage fat are presented as functions of age. Analysis of variance with age, weight, and height as covariates was used to evaluate differences among the three ethnic groups. BMC and LTM were higher in the black than the white females, but no significant difference in BMC or LTM was evident between the white and Hispanic groups. The relation between the BMC and LTM compartments was linear (r = 0.963, P < 0.0005) and independent of age or ethnic classification. The Hispanic and black females had higher percentage fat values than the white group. When adjusted for body size, the Hispanic females continued to have significantly higher fat mass and percentage fat than the white females in this study. Ethnic-specific equations for body composition as a function of age, weight, and height are given. In addition, the results for the white females in the present study were compared with DXA-derived body-composition data for reference populations in other countries. We conclude that reference values of total body composition for young females need to be ethnic-specific.

The aim of this study was to compare the dual-energy X-ray absorptiometry (DXA) measurement of bone mass with an independent measure of body calcium obtained by neutron activation analysis (NAA). Total body bone mineral content (BMC) was measured using DXA in 46 subjects in the age range 5-47 years (17 children, 28 young women, and 1 adult male). Total body calcium (TBCa) was measured in the same subjects by in vivo NAA. The correlation between the two measures of bone mass was highly significant (BMC[g] = 3.22 x TBCa[g] - 51.4, r > 0.98, p < 0.0001, SEEBMC = 122.7 g). When BMC was the independent parameter, the SEETBCa was 37.5 g. Bland-Altman analysis indicated a mean difference of 2.8 g with a standard error +/- 4.7 g for TBCaNAA versus TBCaDXA when the BMC values were converted to TBCa. The relative change in bone mass (delta TBCa/delta BMC) for DXA was higher than that reported for dual-photon absorptiometry versus NAA. The findings presented in this study provide translational equations among the DXA and NAA measurements and for the conversion of total body BMC to TBCa in children and young adults.

Adequate calcium intake is essential for skeletal integrity, particularly during the period of peak bone mass acquisition from 9 to 17 y of age. Currently, the calcium intake of many adolescent girls is below the recommended dietary allowance. The purpose of this study was to evaluate the ability of girls to respond to acute periods of inadequate dietary calcium intake. Calcium absorption was evaluated in 11 girls aged 11.6 +/- 2.4 y after 10 d on both a low-calcium (7.05 +/- 2.03 mmol/d) and a high-calcium (35.30 +/- 2.28 mmol/d) diet. Fractional calcium absorption was determined by using oral (46Ca) and intravenous (42Ca) stable isotopes of calcium. During a low calcium intake, fractional calcium absorption was significantly greater (0.582 +/- 0.087 compared with 0.260 +/- 0.068, P < 0.0001) and urinary calcium excretion was significantly lower (1.30 +/- 0.83 compared with 3.08 +/- 1.98 mmol/d, P < 0.004) than values obtained during a high calcium intake. Concentrations of 1,25-dihydroxyvitamin D (combination of cholecalciferol and ergocalciferol) were greater during the low calcium intake, although the difference was not significant (108.7 +/- 30.6 compared with 90.0 +/- 25.1 pmol/L, P < 0.1; n = 9). Excretion of N-telopeptide was significantly greater during the low calcium intake (761 +/- 508 compared with 413 +/- 341 nmol bone collagen equivalent (BCM)/mmol creatinine, P < 0.02; n = 9), indicating that bone resorption was increased. These results suggest that during short periods of inadequate calcium intake, girls are able to significantly increase the efficiency of calcium absorption and decrease urinary calcium losses to conserve calcium required for bone mineral acquisition.

Three-wk-old genetically lean or obese pigs were used in two experiments to determine the changes in body composition, visceral organs and brain in response to severe protein deficiency. In Experiment 1, 16 obese pigs were fed an adequate (A, 21% protein, 3% fat) or a protein-deficient (D, 5% protein, 23% fat) diet for 7 wk. One-half of each group was killed at 7 wk, and the remainder of each group was fed the A diet for an additional 8 wk. At 7 wk, pigs fed D contained a higher percentage of fat than those fed A (P < 0.01); after 8-wk of repletion, body composition of the two groups was similar. Duodenum, jejunum, and ileum of the protein-deficient pigs had severely atrophic villi, submucosal edema, and atrophic muscle layers; after 8 wk of repletion, however, microscopic architecture of the gastrointestinal tract was restored to normal. Absolute cerebrum weight at 7 wk, but not after 8 wk repletion, in the pigs fed D were significantly less than in pigs fed A, indicating reduced brain cellularity after 7 wk of protein restriction, but not after 8 wk repletion. In Experiment 2, genetically obese (O, n = 8) and lean (L, n = 8) pigs consumed the A or D diet ad libitum for 10 wk. L and O pigs responded similarly to protein deficiency; D pigs were fatter than A pigs and plasma constituents, bone mineral content, bone mineral density and most organ weights revealed no interactions between diet and genotype. The pig model system used in these experiments enabled the isolation of protein deficiency from infectious disease, parasites and social environmental stimulation that may confound interpretation of human infant malnutrition experiments. The data suggest that genetically controlled body fatness is not a major determinant in the response of the infant pig to severe protein deficiency.

Chronic weight loss is a common characteristic of HIV infection; its full etiology remains unknown. We report body composition measurements for 39 adult males with wt loss >= 10% or a body mass index (BMI) below 19.8 kg • m-2 while receiving stable antiretroviral therapy, and no recent history of opportunistic infection, malignancy, Kaposi sarcoma, or therapy with anabolic agents. CD4+ counts ranged from 2 to 531; 30 subjects having counts <= 200. Body composition was measured by 40K counting, dual-energy X-ray absorptiometry (DXA), and anthropometry. The reference body composition measures were total body potassium (TBK), lean tissue mass (LEAN), fat mass (FAT), and percentage body fat (%FAT). In addition, nutritional assessment was based on a 2-d food diary. The mean TBK was 90.2% ± 10.8% of normal controls, while the %FAT averaged only 14.4% ± 5.3%, also below the normal range. Reasonable estimates of these body composition compartments were obtained using a combination of BMI, mid-arm circumference (MAC), and triceps skinfold measurements (TSF).

Absolute amounts of cadmium (in milligrams) in the left kidney and concentrations of cadmium (micrograms per gram) in the liver were measured in vivo in 20 healthy adult male volunteers. Organ cadmium levels of smokers were significantly elevated above those of nonsmokers. No relationship was evident between body stores of cadmium (liver and kidney) and cadmium or beta 2-microglobulin in urine or blood. The average total body burden of cadmium in man at age 50 is estimated to be 19.3 milligrams for nonsmokers and 35.5 milligrams for smokers (38.7 pack-year smoking history). Biological half-time for the whole body was, on average, 15.7 years (10- to 33-year range). Dietary absorption was 2.7 micrograms per day. Cigarette smoking resulted in the absorption of 1.9 micrograms per pack.

The primary objective of this study was to develop dose-response relationships of cadmium in human beings. In vivo measurements of kidney, liver, urine, and blood cadmium, and urinary levels of beta 2-microglobulin and total protein were obtained in 82 industrially exposed workers and 30 control subjects. The values of 200 micrograms/g creatinine for urinary beta 2-microglobulin and 250 mg/g creatinine for urinary total protein were used to define the upper limit for normal kidney function. Forty-one of the cadmium workers (18 active, 23 retired) were classified as having abnormal kidney function; all control subjects had normal kidney function. Most workers with Cd above 70 ppm in the liver were judged to have some evidence of kidney abnormalities. The dose-response relationship for liver cadmium for the actively employed workers could be described by a linear logistic regression model: (Formula: see text) where p is the individual's probability of having kidney dysfunction. The loss of cadmium from the kidney following dysfunction prohibited a direct logistic analysis of the kidney cadmium data. However, when the linear relationship between kidney and liver cadmium for the subjects with normal kidney function was combined with the logistic equation for the liver, a predicted-response curve was obtained for the kidney. The logistic models predict a 50% probability of having kidney dysfunction at 38.4 mg for the kidney and 42.3 ppm for the liver, respectively.

Studies were undertaken to determine the biologic distribution of thallium-201 in man. The disappearance from the blood is extremely rapid and intracellular deposition is nearly immediate. The biologic half-time of thallium was measured by both the Brookhaven whole-body counter and the Donner whole-body scanner, with excellent agreement. The effective whole-body half-time of thallium-201 is about 57 hr. Concentration of activity was seen in the heart, kidneys, large bowel, and thyroid. The whole-body radiation dose is 0.21 rads/mCi.

The total-body retention of 127Xe, and its variation with time following short, nonequilibrium periods of inhalation, were measured in vivo so as to refine dosimetry calculations. Radioactivity in the chest region and in the recirculating xenon-air mixture was measured continuously during re-breathing of the gas mixture and in the first 5 min of the immediate gas-washout period using a scintillation camera and shielded NaI detector, respectively. Subjects were then counted in a whole-body counter at varying time intervals until background levels were reached, usually in 72 hr. Five components of Xe clearance from the entire body were measured; they had biologic half-times of 21.7+/-12.4 sec, 3.05+/-1.72 min, 0.04+/-0.11 hr, and 2.71+/-0.87 hr, and a long-term component varied between 7.59 and 17.04 hr. The half-time of the last component correlated highly with the percent of total-body fat. After 10-min inhalations of the xenon-air mixture, approximately one-third of the total xenon was transferred to the body tissues, extrapolated back to the start of gas washout. Of this amount, 13% was associated with the slowest component of clearance.

A method for the in vivo determination of body nitrogen by prompt gamma photons from neutron capture is described. An 85-Ci 238Pu-Be source provides the neutrons. The gamma detection system consists of two 15.24 x 15.24 cm Nal(TI) detectors placed above the patient. Absolute value of body nitrogen is determined using body hydrogen as an internal standard. The reproducibility of the method is +/- 3% for a body dose of 26 mrem.