Clindamycin release determined by high performance liquid chromatography from a novel low-cost local drug delivery system: a new potential treatment option for chronic osteomyelitis.

Osteomyelitis continues to be a severe problem worldwide, causing plenty of hospital admissions and entailing vast expenses. Previously, we developed a low-cost polymethyl-methacrylate (PMMA)-sorbitol based capsule system for local long-term drug delivery. In the present study we aimed to test the in vitro release of clindamycin capsules by high performance liquid chromatography. By the end of the clinically relevant period (42 days), the capsules released 70-100% of their load. Furthermore, the release kinetics suggested that an effective antimicrobial concentration may be maintained within the target area. Our findings indicate that these newly developed capsules may be a versatile device for local clindamycin delivery by providing efficient release and reducing financial burdens.

Do hormonal indices of maturation explain energy expenditure differences in African American and Caucasian prepubertal children?

OBJECTIVE: To examine the relationships between hormonal indices of maturation and total, resting and physical activity-related energy expenditure (TEE, REE and AEE) in African American and Caucasian prepubertal children. DESIGN: Cross-sectional study. SUBJECTS: Sixty-four African American and 48 Caucasian prepubertal children. MEASUREMENTS: TEE (by doubly labeled water), REE (by indirect calorimetry), fat mass and fat-free mass (by dual-energy X-ray absorptiometry), fasting serum dehydroepiandrosterone-sulfate (DHEAS), androstenedione, and estrone-sulfate (by radioimmunoassay). RESULTS: Serum concentrations of hormones correlated significantly with REE and TEE (r values range from 0.33 to 0.76, P<0.001). Only androstenedione correlated significantly with AEE (r = 0.23, P<0.05). However, these correlations were no longer significant after adjusting energy expenditure components for fat-free mass. In multiple regression models, ethnicity was not a significant determinant of any energy expenditure component after adjusting for body composition and hormone concentrations. CONCLUSION: Hormonal indices of maturation do not influence energy expenditure in this group of African American and Caucasian prepubertal children.

Influence of sex, seasonality, ethnicity, and geographic location on the components of total energy expenditure in young children: implications for energy requirements.

BACKGROUND: There are limited data on the influence of body composition, sex, seasonality, ethnicity, and geographic location on the components of energy expenditure in children. OBJECTIVE: The objective was to examine the determinants of total energy expenditure (TEE), resting energy expenditure (REE), and activity-related energy expenditure (AEE) in children. DESIGN: Cross-sectional data from 232 children (4-10 y of age) from 4 ethnic groups (white American, African American, Guatemalan Mestizo, and Native American Mohawk) were examined. RESULTS: In 104 white children studied in Vermont and Alabama, TEE was significantly higher in spring than in fall, higher in boys than in girls, and higher in children in Vermont (all effects: approximately 0.42 MJ/d, P < 0.05). The significant effect of sex was explained through REE; the influences of season and location were explained through AEE. In all children, there was no effect of sex but a significant effect of ethnicity (P < 0.01) on TEE: a significant effect of sex (P < 0.01) and no effect of ethnicity (P = 0.16) on REE; and no effect of sex and a significant effect of ethnicity on AEE. The significant effects of ethnicity were due to lower values in Guatemalan children. TEE correlated most strongly with weight (r = 0.81) and fat-free mass (r = 0.79-0.81); REE with weight (r = 0.85) and fat-free mass (r = 0.80-0.87); and AEE with maximal oxygen consumption (r = 0.54), fat-free mass (r = 0.50), and fat mass (r = 0.49). CONCLUSIONS: 1) Season and location influenced TEE in children through their effects on AEE, 2) a higher REE in boys was consistent across all groups examined, 3) Guatemalan children had lower TEE due to a lower AEE, 4) body weight may be the best predictor of TEE, and 5) maximal oxygen consumption was the strongest marker of AEE.

Developmental changes in energy expenditure and physical activity in children: evidence for a decline in physical activity in girls before puberty.

OBJECTIVE: To examine individual changes in energy expenditure and physical activity during prepubertal growth in boys and girls. METHODS: Total energy expenditure (TEE), resting energy expenditure, physical activity-related energy expenditure, reported physical activity, and fat and fat-free mass were measured three times over 5 years in 11 boys (5.3 +/- 0.9 years at baseline) and 11 girls (5.5 +/- 0.9 years at baseline). RESULTS: Four-year increases in fat ( approximately 6 kg) and fat-free mass ( approximately 10 kg) and resting energy expenditure ( approximately 200 kcal/day) were similar in boys and girls. In boys, TEE increased at each measurement year, whereas in girls, there was an initial increase from age 5.5 (1365 +/- 330 kcal/day) to age 6.5 (1815 +/- 392 kcal/day); however, by age 9.5, TEE was reduced significantly (1608 +/- 284 kcal/day) with no change in energy intake. The gender difference in TEE changes over time was explained by a 50% reduction in physical activity (kcal/day and hours/week) in girls between the ages of 6.5 and 9.5. CONCLUSIONS: These data suggest a gender dimorphism in the developmental changes in energy expenditure before adolescence, with a conservation of energy use in girls achieved through a marked reduction in physical activity.

Total, resting, and activity-related energy expenditures are similar in Caucasian and African-American children.

There is some evidence to suggest that ethnic differences in energy expenditure in adults may modulate different propensities for obesity. However, there is lack of data for the components of energy expenditure in young children of different ethnic backgrounds. In this study, we examined total energy expenditure (TEE), resting energy expenditure (REE), and physical activity-related energy expenditure (AEE) in healthy prepubertal Caucasian (18 girls, 21 boys) and African-American (29 girls, 30 boys) children. TEE was measured over 14 days under free-living conditions with the doubly labeled water technique, REE was from indirect calorimetry after an overnight fast, and AEE was estimated from the difference between TEE and REE after reducing TEE by 10% to account for the thermic effect of feeding. Fat mass (FM) and fat-free mass (FFM) were measured by dual-energy X-ray absorptiometry. There were no significant effects of ethnicity or gender on TEE after adjustment for FFM or for both FFM and FM. For REE, there was no effect of ethnicity, but a significant effect of gender, with a higher REE in boys after adjustment for FFM and FM (P < 0.001). For AEE, there were no significant effects of ethnicity or gender after adjustment for FFM or for FFM and FM. In conclusion, ethnicity was not a significant determinant for any of the components of energy expenditure. TEE, REE, and AEE were similar in Caucasian and African-American prepubertal children after adjustment for FFM or for FFM and FM.

Longitudinal changes in fatness in white children: no effect of childhood energy expenditure.

Reduced energy expenditure may predispose children to the development of obesity, but there are limited longitudinal studies to support this theory. We studied 75 white, preadolescent children over 4 y by taking annual measures of body composition and resting energy expenditure (by indirect calorimetry) and two annual measures of total energy expenditure and physical-activity-related energy expenditure (by doubly labeled water). Body composition of parents was assessed at the onset of the study with use of underwater weighing. The major outcome variable was the individual rate of change in fat mass (FM) adjusted for fat-free mass (FFM). The influence of sex, energy expenditure components, initial FM, and parental FM on the rate of change in FM was analyzed by hierarchical linear modeling and analysis of variance. The rate of change in absolute FM was 0.89 +/- 1.08 kg/y (range: -0.44 to 5.6 kg/y). The rate of change in FM adjusted for FFM was 0.08 +/- 0.64 kg/y (range: -1.45 to 2.22 kg/y) and was similar among children of two nonobese parents and children with one nonobese or one obese parent, but was significantly higher in children with two obese parents (0.61 +/- 0.87 kg/y). The major determinants of change in FM adjusted for FFM were sex (greater fat gain in girls), initial fatness, and parental fatness. None of the components of energy expenditure were inversely related to change in FM. The main predictors of change in FM relative to FFM during preadolescent growth are sex, initial fatness, and parental fatness, but not reduced energy expenditure.

Serum leptin and energy expenditure in children.

Leptin has been hypothesized to play an important role in energy balance by affecting both energy intake and energy expenditure. The purpose of our study was to determine the relationship between fasting serum leptin concentrations and measures of energy expenditure in prepubertal children. We measured total energy expenditure (TEE; by the doubly labeled water technique), resting energy expenditure (REE; after an overnight fast), activity energy expenditure (AEE; TEE-REE), body composition (by dual energy x-ray absorptiometry), and fasting serum leptin concentration (by RIA) in 76 children. Simple correlations showed that all measures of energy expenditure (TEE, REE, and AEE) were positively related to the serum leptin concentration (r = 0.50, P < 0.001; r = 0.45, P < 0.001; and r = 0.30, P < 0.01, respectively). However, after adjusting for body composition (fat-free mass and fat mass), gender, and ethnicity, serum leptin concentrations were not related to any measure of energy expenditure (TEE, P = 0.61; REE, P = 0.97; AEE, P = 0.65). These latter findings were further confirmed using structural equation models with leptin and energy expenditure as dependent variables, and fat-free mass and fat mass as independent variables. Results from these models showed no direct effect of leptin and no indirect effect of fat mass (through leptin) on any measure of energy expenditure, when a path between fat mass and energy expenditure was present in the model. Thus, our data do not support the hypothesis that the serum leptin concentration (independent of fat mass) is related to measures of energy expenditure in children.

Physical activity related energy expenditure and fat mass in young children.

OBJECTIVE: To examine whether body fat content in pre-pubertal children is influenced by physical activity related energy expenditure (AEE) and/or more qualitative aspects of physical activity. DESIGN: Cross-sectional study. SUBJECT: 101 pre-pubertal children were examined in Study 1: (age: 5.3 +/- 0.9 y; weight: 20.2 +/- 3.6 kg). In Study 2: 68 of the original children were re-examined (age: 6.3 +/- 0.9 y; weight: 23.6 +/- 5.0 y). MEASUREMENT: Fat mass (FM) and fat free mass (FFM) were determined by bioelectrical resistance and skinfolds; AEE was estimated from the difference between total energy expenditure (TEE) by doubly labeled water and post-prandial resting energy expenditure (REE) by indirect calorimetry; qualitative information on activity was derived by questionnaire. RESULTS: AEE was significantly correlated with FFM (r = 0.32 in both Studies) and body weight (r = 0.28 in Study 1; r = 0.29 in Study 2), but not FM. There were no significant relationships between AEE and any of the variables from the activity questionnaire in children (including TV time, playing time, and an accumulated activity index in h/week). After adjusting for FFM, age, and gender, FM was inversely related to activity time in h/week (partial r = -0.24 in Study 1; partial r = -0.32 in Study 2) but not AEE (P > 0.5). CONCLUSION: After adjusting for FFM, age, and gender, a small portion of the variance in body fat mass in children (approximately 10%) is explained by time devoted to recreational activity, whereas none of the variance is explained by the combined daily energy expenditure related to physical activity.

Acute water shortage and health problems in Haiti.

During a severe drought Port-au-Prince, Haiti, lost hydroelectric power for 10 weeks. This led to water shortages in areas of the city dependent on water supplied from electrically driven pumps. In a study of the impact of water restriction on disease, 400 families were randomly selected from two urban areas differentially affected by the water shortage. Disease in children was found to be related to quantity of water used, socioeconomic status, employment of head of household, and family size. The methods used in this study are recommended for the investigation of the relationship between water quantity and health.