Cellular signaling in pseudoxanthoma elasticum: an update.

Pseudoxanthoma elasticum is an autosomal recessive genodermatosis with variable expression, due to mutations in the ABCC6 or ENPP1 gene. It is characterized by elastic fiber mineralization and fragmentation, resulting in skin, eye and cardiovascular symptoms. Significant advances have been made in the last 20 years with respect to the phenotypic characterization and pathophysiological mechanisms leading to elastic fiber mineralization. Nonetheless, the substrates of the ABCC6 transporter - the main cause of PXE - remain currently unknown. Though the precise mechanisms linking the ABCC6 transporter to mineralization of the extracellular matrix are unclear, several studies have looked into the cellular consequences of ABCC6 deficiency in PXE patients and/or animal models. In this paper, we compile the evidence on cellular signaling in PXE, which seems to revolve mainly around TGF-ßs, BMPs and inorganic pyrophosphate signaling cascades. Where conflicting results or fragmented data are present, we address these with novel signaling data. This way, we aim to better understand the up- and down-stream signaling of TGF-ßs and BMPs in PXE and we demonstrate that ANKH deficiency can be an additional mechanism contributing to decreased serum PPi levels in PXE patients.

Adjusting diet-outcome associations for random error: comparison of associations based on observed and estimated usual intakes.

BACKGROUND/OBJECTIVES: To compare linear regression coefficients adjusted for random errors with true coefficients. SUBJECTS/METHODS: Three hundred and two individuals from the city of Rio de Janeiro, Brazil answered 20 non-consecutive 24-hr. Means of 20 24-hr were used as an approximation of the usual dietary intakes. It was simulated outcomes with pre-defined linear regression coefficient (ß=1.0, referred as 'true coefficient') for usual coffee and soft-drink intakes as explanatory variables controlled for sex and age. Regression calibration was applied in each 1000 random combinations of j days of intake (j=2, 4 and 6), and adjusted coefficients were compared with true one. RESULTS: Mean-adjusted coefficients were 1.06 to 1.03 (coffee) and 1.17 to 1.11 (soft drink). The association was not detected (95% CI included zero) in 33 to 23% (coffee) and 37 to 23% (soft drink) when using two and six collection days, respectively, compared with 20% when using observed usual intake. Frequency of consumption as covariate in the regression calibration model increased the precision of the adjusted coefficients. CONCLUSIONS: Adjustment for random errors de-attenuates the association but its precision depends mainly on the number of collection days and sample size.

Is the food frequency consumption essential as covariate to estimate usual intake of episodically consumed foods?

UNLABELLED: BACKGROUNDS/OBJECTIVES: The aim of this paper is to verify the performance of the frequency of consumption as variable for prediction of the usual intakes of foods. SUBJECTS/METHODS: In total, 725 individuals who answered two nonconsecutive 24-h recall and one food frequency questionnaire (FFQ) in the 'Healthy Survey-Sao Paulo-Brazil'. An additional indicator variable indicating if one is usual consumer was created before analyzing. The Multiple Source Method and National Cancer Institute method were used to estimate usual intake of selected food considering different models of prediction: with no covariates; with FFQ; with FFQ plus indicator variable; and with only indicator variable. RESULTS: For foods that are consumed every day or almost every day, the inclusion of the FFQ and/or the indicator variable as covariates resulted in similar percentiles of consumption when compared with the model with no covariates. For episodically consumed foods, the models with FFQ plus indicator variable and with only indicator variable estimated similar percentiles of intake. CONCLUSIONS: The use of the indicator variable instead the FFQ appears as a good alternative to estimate usual intake of episodically consumed foods.

The influence of breakfast and dairy products on dietary calcium and vitamin D intake in postpubertal adolescents and young adults.

BACKGROUND: Given the importance of both calcium and vitamin D for bone health and the high prevalence of vitamin D from around the world, the present study aimed to evaluate calcium and vitamin D intake in a group of healthy Brazilian adolescents and young adults and to examine the influence of breakfast and dairy products in the total intake of these nutrients. METHODS: One hundred and sixty adolescents and young adults, aged 16-20 years old, from a public school, participated in the present study. Three-day dietary records were used to assess calcium and vitamin D intakes. Serum 25(OH)D levels were measured using a radioimmunoassay kit. The results were expressed as the mean (SD). RESULTS: Only 3.8% of the subjects met the daily adequate intake recommendation for calcium, and none for vitamin D [682.2 (132.2)mg day(-1) and 124.0 (28.0)IU day(-1) , respectively]. 25(OH)D serum levels were insufficient in 51.5% and deficient in 9.7% of the individuals [72.5 (22.3) nmol L(-1) ]. There was a significant positive correlation between dairy product intake with both calcium and vitamin D (r=0.597 and r =0.561, respectively; P=0.000). Adolescents who ate breakfast had a significant higher mean calcium, vitamin D and dairy product intake than adolescents who did not report this meal. CONCLUSIONS: The majority of adolescents and young adults did not consume recommended intakes of calcium and vitamin D and also presented 25(OH)D insufficiency. The results indicate that a regular breakfast and the consumption of dairy products represent important strategies in improving calcium and vitamin D intake in the diet.

Demonstration of size variation of RNA segments between different isolates of calf rotavirus.

Polyacrylamide gel electrophosesis of RNA extracted from wild rotavirus isolates and cell culture adapted virus revealed a significant variation in the molecular weight of individual RNA segments. The major differences were observed between wild isolates on the one hand and the adapted strain on the other hand. The slight variations that were observed between different wild isolates were found regularly and appeared to be related to the origin of the samples.