Estimating dietary consumption patterns among children: a comparison between cross-sectional and longitudinal study designs

Estimating dietary intake for children is an essential component of conducting pesticide exposure assessments given the fact that children are predominantly exposed to certain pesticides, such as organophosphorus pesticide, through dietary intake. Different study designs and their respective sampling methodology utilized to estimate food consumption patterns can significantly alter the parameter estimates and the variability in the values obtained. This study investigated the impacts of study design on overall estimates of dietary intake by applying the temporal sampling characteristics used in cross-sectional approaches, as in The Continuing Survey of Food for Intakes by Individuals (CSFII), to food consumption data collected in a longitudinal manner via a bootstrap sampling technique. We examined the precision of time-averaged dietary intake estimates under various sampling schemes and explored the contribution of seasonality toward the dietary patterns. A comparison between the estimates of food consumption obtained from the bootstrap replicates and the longitudinal study estimates indicate that variability is significantly decreased when employing a longitudinal study design. Moreover, both between and within-subject variability decreases when individuals are followed over an increasing number of days. Finally, within the longitudinal study cohort, we observed a seasonal component to dietary intake for fruits and grains. Our findings suggest that longitudinal dietary surveys offer substantial improvements for exposure assessment compared to a standard cross-sectional design.     

Effects of Anion-Transport Inhibitors on NaCl Reabsorption in the Rat Superficial Proximal Convoluted Tubule

The effects of anion-transport inhibitors on volume reabsorption, and total CO(2) concentrations were examined by in vivo microperfusion of superficial proximal convoluted tubules of rats. The luminal perfusion solution was a high-chloride, low-bicarbonate solution like that in the in vivo late proximal tubule. The anion-transport inhibitors were only added to the luminal perfusion solutions.In tubules perfused with the control high-chloride solution, the rate of volume reabsorption (J(v)) was 2.3+/-0.2 nl/mm.min (n = 18), and the collected total CO(2) concentration was 4.0+/-0.3 mM. Furosemide (3 mM) caused a marked reduction in volume reabsorption to 0.8+/-0.3 nl/mm.min (n = 20) and only a slight increase in the total CO(2) concentration of collected samples of perfusate (7.8+/-0.5 mM). 0.8 mM acetazolamide caused a more pronounced rise in the collected total CO(2) concentrations to 10.7+/-0.5 mM but only a slight fall in J(v) to 1.7+/-0.3 nl/mm.min (n = 19). Hence, we inferred that inhibition of carbonic anhydrase only partially accounted for the inhibition of J(v) by furosemide. 4-acetamido-4'-iso-thiocyanato-stilbene-2,2'-disulphonic acid (0.1 mM), a well-characterized inhibitor of erythrocyte anion exchange mechanisms, also reduced J(v) to 1.6+/-0.3 nl/mm.min (n = 15) without changing the total CO(2) concentrations of the collected perfusates (3.6+/-0.4 mM). The effect of 4-acetamido-4'-iso-thiocyanato-stilbene-2,2'-disulphonic acid on volume reabsorption could not be explained by carbonic anhydrase inhibition because there was no increase in the total CO(2) concentration of the collected fluids. Furosemide did not significantly inhibit the rate of tracer glucose efflux out of the tubules, which suggests that the effect of furosemide on volume reabsorption was not a result of some nonspecific depression of active sodium transport. These results are discussed with respect to the possible effects of anion-transport inhibitors on the paracellular shunt pathway, active sodium reabsorption, and neutral sodium chloride transport.     

Is there an association between early weight status and utility-based health-related quality of life in young children?

Purpose

Few studies focus on the health-related quality of life (HRQoL) of preschool children with overweight or obesity. This is relevant for evaluation of obesity prevention trials using a quality-adjusted life year (QALY) framework. This study examined the association between weight status in the preschool years and HRQoL at age 5 years, using a preference-based instrument.

Methods

HRQoL [based on parent proxy version of the Health Utilities Index Mark 3 (HUI3)] and weight status were measured in children born in Australia between 2007 and 2009. Children’s health status was scored across eight attributes of the HUI3—vision, hearing, speech, ambulation, dexterity, emotion, cognition and pain, and these were used to calculate a multi-attribute utility score. Ordinary least squares (OLS), Tobit and two-part regressions were used to model the association between weight status and multi-attribute utility.

Results

Of the 368 children for whom weight status and HUI3 data were available, around 40% had overweight/obesity. After adjusting for child’s sex, maternal education, marital status and household income, no significant association between weight status in the preschool years and multi-attribute utility scores at 5 years was found.

Conclusions

Alternative approaches for capturing the effects of weight status in the preschool years on preference-based HRQoL outcomes should be tested. The application of the QALY framework to economic evaluations of obesity-related interventions in young children should also consider longitudinal effects over the life-course.Clinical Trial Registration The Healthy Beginnings Trial was registered with the Australian Clinical Trial Registry (ACTRNO12607000168459).

     

Clinicogenetic lessons from 370 patients with autosomal recessive limb-girdle muscular dystrophy

Limb-girdle muscular dystrophies (LGMD) are a group of genetically heterogeneous disorders characterized by predominantly proximal muscle weakness. We aimed to characterize epidemiological, clinical and molecular data of patients with autosomal recessive LGMD2/LGMD-R in Brazil. A multicenter historical cohort study was performed at 13 centers, in which index cases and their affected relatives' data from consecutive families with genetic or pathological diagnosis of LGMD2/LGMD-R were reviewed from July 2017 to August 2018. Survival curves to major handicap for LGMD2A/LGMD-R1-calpain3-related, LGMD2B/LGMD-R2-dysferlin-related and sarcoglycanopathies were built and progressions according to sex and genotype were estimated. In 370 patients (305 families) with LGMD2/LGMD-R, most frequent subtypes were LGMD2A/LGMD-R1-calpain3-related and LGMD2B/LGMD-R2-dysferlin-related, each representing around 30% of families. Sarcoglycanopathies were the most frequent childhood-onset subtype, representing 21% of families. Five percent of families had LGMD2G/LGMD-R7-telethonin-related, an ultra-rare subtype worldwide. Females with LGMD2B/LGMD-R2-dysferlin-related had less severe progression to handicap than males and LGMD2A/LGMD-R1-calpain3-related patients with truncating variants had earlier disease onset and more severe progression to handicap than patients without truncating variants. We have provided paramount epidemiological data of LGMD2/LGMD-R in Brazil that might help on differential diagnosis, better patient care and guiding future collaborative clinical trials and natural history studies in the field.     

Intracellular injection of vital dyes into single cells in the salamander olfactory epithelium

Intracellular vital dye injection was used to examine the morphology of single sustentacular and receptor cells and the developmental fate of individual basal cells in the olfactory epithelium of the tiger salamander. In acute experiments, Lucifer yellow injections were used to identify single basal, receptor or sustentacular cells on the basis of their overall morphology. Dye-coupling between a number of the different epithelial cells was observed. Progeny of basal cells were examined by following labeled cells for up to 2 weeks using intracellular injection of rhodamine-labeled dextran. These experiments indicate that some olfactory epithelial cells are dye-coupled and that dye-filled basal cells can undergo division and migration.     

Blood Volume Changes in Splenomegaly

S ummary . Blood volume changes have been measured in 65 patients with splenomegaly due to a miscellany of causes. The red-cell mass is often normal despite the fact that anaemia is present, and the anaemia is in part due to sequestration of red cells in a splenic pool and haemodilution of the red cells in an expanded plasma volume. Both factors may be relieved by splenectomy although the ultimate prognosis is dependent on the primary disease present.