The doubly labeled water (DLW) method is used to measure free-living energy expenditure in humans... more The doubly labeled water (DLW) method is used to measure free-living energy expenditure in humans. Inherent to this technique is the assumption that natural abundances of stable isotopes (2)H and (18)O in body water remain constant over the course of the measurement period and after elimination of the loading dose of doubly-labeled water will return to the same pre-dose level. To determine variability in the natural abundances of (2)H and (18)O in humans living in a region with seasonal shifts in rain patterns and sources of drinking water, over the course of 12 months we collected weekly urine samples from four individuals living in southwest Nigeria as well as samples of their drinking water. From ongoing regional studies of hypertension, obesity and energy expenditure, average water turnover rate, urine volumes and sodium and potassium excretion were estimated. Results suggest that 2H and 18O in urine, mean concentrations of urinary sodium and potassium, urine volume, and total body turnover differed significantly from dry to rainy season. Additionally, seasonal weather variables (mean monthly maximum temperatures, total monthly rainfall, and minimum relative humidity) were all significantly associated with natural abundances in urine. No seasonal difference was observed in drinking water samples. Findings suggest that natural abundances in urine may not remain constant as assumed and studies incorporating DLW measurements across the transition of seasons should interpret results with caution unless appropriate doses of the tracers are used.
The hepatitis C virus (HCV), which was not recognized as an infectious agent until the 1980s, is ... more The hepatitis C virus (HCV), which was not recognized as an infectious agent until the 1980s, is responsible for a worldwide epidemic. The World Health Organization estimates global prevalence at 2.8%, with 185 million persons infected. In contrast to hepatitis B, where successful vaccine campaigns have reduced the disease burden, much less progress has been made toward the control of HCV. Phylogenetic studies suggest that HCV originated in Africa and has been endemic in some regions for at least 500-600 years. However, little is known about the epidemiology, transmission, and clinical course of HCV in Africa. With the advent of highly effective anti-HCV agents, there exists great potential to at least curb the global epidemic. For regions such as sub-Saharan Africa, however, this will require a thorough understanding of the regional population-level epidemiology, risk factors, and transmission mechanisms. Only then can effective treatment and prevention strategies be introduced.
The tens of thousands of catch basins found in many urban areas are a primary target of local vec... more The tens of thousands of catch basins found in many urban areas are a primary target of local vector control agencies for seasonal application of extended-release larvicides. A concern with using larvicides in these structures is that active ingredients can be hampered by high flows, debris, and sediment, all of which are common to these structures. As such a certain proportion of basins may be "resistant" to larvicide treatments due to site specific characteristics that may promote these and other factors that hinder larvicide action and/or promote mosquito infestation. Analyses from three years of larvicide efficacy trials suggest that over a quarter of basins in the study area may not be receiving adequate protection from a single dose of larvicide that is routinely applied. Implications of increasing the dose and/or toxicity of larvicide treatments are discussed further.
Low-income minority females are disproportionately affected by obesity. The relevance of summer m... more Low-income minority females are disproportionately affected by obesity. The relevance of summer months to weight gain is often overlooked. Some evidence suggests that summer programming, such as day camps, may offer increased opportunities for structured physical activities resulting in less weight gain. This study examined the effectiveness of Girls in the Game, a six-hour four-week sports and fitness summer camp program, in increasing physical activity (PA) and reducing body mass index and media use. Statistically significant increases were observed in four physical activity measures including total PA, MVPA, average number of ten-minute bouts of MVPA, and minutes participants spent in bouts of at least ten minutes of MVPA. This chapter highlights the importance of investigating the potential relationships among weight, physical activity, sedentary time, media use, and participation in summer camp programming.
The doubly labeled water (DLW) method is used to measure free-living energy expenditure in humans... more The doubly labeled water (DLW) method is used to measure free-living energy expenditure in humans. Inherent to this technique is the assumption that natural abundances of stable isotopes (2)H and (18)O in body water remain constant over the course of the measurement period and after elimination of the loading dose of doubly-labeled water will return to the same pre-dose level. To determine variability in the natural abundances of (2)H and (18)O in humans living in a region with seasonal shifts in rain patterns and sources of drinking water, over the course of 12 months we collected weekly urine samples from four individuals living in southwest Nigeria as well as samples of their drinking water. From ongoing regional studies of hypertension, obesity and energy expenditure, average water turnover rate, urine volumes and sodium and potassium excretion were estimated. Results suggest that 2H and 18O in urine, mean concentrations of urinary sodium and potassium, urine volume, and total body turnover differed significantly from dry to rainy season. Additionally, seasonal weather variables (mean monthly maximum temperatures, total monthly rainfall, and minimum relative humidity) were all significantly associated with natural abundances in urine. No seasonal difference was observed in drinking water samples. Findings suggest that natural abundances in urine may not remain constant as assumed and studies incorporating DLW measurements across the transition of seasons should interpret results with caution unless appropriate doses of the tracers are used.
The hepatitis C virus (HCV), which was not recognized as an infectious agent until the 1980s, is ... more The hepatitis C virus (HCV), which was not recognized as an infectious agent until the 1980s, is responsible for a worldwide epidemic. The World Health Organization estimates global prevalence at 2.8%, with 185 million persons infected. In contrast to hepatitis B, where successful vaccine campaigns have reduced the disease burden, much less progress has been made toward the control of HCV. Phylogenetic studies suggest that HCV originated in Africa and has been endemic in some regions for at least 500-600 years. However, little is known about the epidemiology, transmission, and clinical course of HCV in Africa. With the advent of highly effective anti-HCV agents, there exists great potential to at least curb the global epidemic. For regions such as sub-Saharan Africa, however, this will require a thorough understanding of the regional population-level epidemiology, risk factors, and transmission mechanisms. Only then can effective treatment and prevention strategies be introduced.
The tens of thousands of catch basins found in many urban areas are a primary target of local vec... more The tens of thousands of catch basins found in many urban areas are a primary target of local vector control agencies for seasonal application of extended-release larvicides. A concern with using larvicides in these structures is that active ingredients can be hampered by high flows, debris, and sediment, all of which are common to these structures. As such a certain proportion of basins may be "resistant" to larvicide treatments due to site specific characteristics that may promote these and other factors that hinder larvicide action and/or promote mosquito infestation. Analyses from three years of larvicide efficacy trials suggest that over a quarter of basins in the study area may not be receiving adequate protection from a single dose of larvicide that is routinely applied. Implications of increasing the dose and/or toxicity of larvicide treatments are discussed further.
Low-income minority females are disproportionately affected by obesity. The relevance of summer m... more Low-income minority females are disproportionately affected by obesity. The relevance of summer months to weight gain is often overlooked. Some evidence suggests that summer programming, such as day camps, may offer increased opportunities for structured physical activities resulting in less weight gain. This study examined the effectiveness of Girls in the Game, a six-hour four-week sports and fitness summer camp program, in increasing physical activity (PA) and reducing body mass index and media use. Statistically significant increases were observed in four physical activity measures including total PA, MVPA, average number of ten-minute bouts of MVPA, and minutes participants spent in bouts of at least ten minutes of MVPA. This chapter highlights the importance of investigating the potential relationships among weight, physical activity, sedentary time, media use, and participation in summer camp programming.
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