STRUCTURE-FUNCTION ANALYSIS OF MYC/MAX-DNA BINDING

The c-Myc oncoprotein (or Myc) is a transcription factor of the basic-Helix-Loop-Helix Leucine-zipper (bHLH-LZ) family, whose transcriptional activity depends on dimerization with the bHLH-LZ partner Max and DNA binding, mediated by the basic regions of both proteins. Myc/Max dimers bind preferentially to the hexanucleotide motif CACGTG (known as E-box) and variants thereof. The ability of Myc to bind DNA in vivo, however, is not stringently regulated by the presence of the E-box, since many genomic sites targeted by Myc do not contain this motif. Hence, we still need to fully comprehend how Myc recognizes its genomic targets and to what extent sequence-specific DNA binding contributes to this process. Based on the crystal structure of the DNA-bound Myc/Max dimer, we generated a Myc mutant in which two basic region residues engaged in sequence-specific contacts (H359 and E363) were mutated to Alanine (Myc HEA), and compared this with a mutant in which three Arginine residues involved in DNA backbone interactions were mutated to Alanine (Myc RA). While both mutants showed impaired E-box recognition in vitro, their over-expression in murine fibroblasts revealed very different genome-interaction profiles, Myc RA showing no detectable DNA binding, and Myc HEA retaining about half of the binding sites seen with Myc wt. The analysis of the binding intensity of Myc wt and Myc HEA at their binding sites revealed that, as expected, Myc wt bound more strongly the sites containing the E-box, while Myc HEA bound the sites with an E-box as well as the sites without it, confirming that the mutant lost the sequence-specific recognition ability. The interactions retained by the Myc HEA were dramatically reduced with the protein expressed from the endogenous c-myc locus, though genome engineering. Thus, unlike Myc RA, the Myc HEA mutant retained non-specific interactions with genomic DNA (detectable at elevated protein levels) but failed to engage more stably through sequence-specific DNA contacts. In spite of this residual DNA-binding activity, Myc HEA was profoundly impaired in its biological function, undistinguishable from Myc RA: in particular, neither mutant could substitute for wild-type Myc in supporting cell proliferation in murine fibroblasts, whether at normal or supra-physiological levels. While the assessment of transcriptional activities is still ongoing, we conclude that E-box recognition is essential for Myc\u2019s biological function

Trends and determinants of change in compliance to dietary guidelines in a Swiss community-dwelling sample.

Adherence to dietary guidelines is associated with significantly better health outcomes. Studies across the world shows that compliance with the guidelines was low, but data in Switzerland are lacking. Hence, we aimed to assess the 5-year trends in dietary compliance regarding food guidelines in Switzerland in a prospective, population-based observational study. Data from 2882 participants (1591 women, 35-75 years), from the first (2009-2012) and second (2014-2017) follow-up. Dietary intake was assessed using a validated food frequency questionnaire. Compliance with the guidelines of the Swiss society of nutrition was assessed at baseline and 5.5 years afterwards. Prevalence rates for compliance were calculated using the exact Poisson method. Factors associated with changes in compliance (never, shifter or maintainer) were assessed by multinomial logistic regression using "Never compliers" as reference. Overall, improvements in compliance to fruits (42.4% to 45.1%) vegetables (6.9% to 8.6%) and fish (66.6% to 60.5%) were found, while compliance to meat decreased (61.1% to 58.5%). The prevalence of participants complying with at least three dietary recommendations did not change (24.1% to 25.2%). During follow-up, only 11.6% of participants maintained compliance to at least three dietary recommendations, and 62.4% never managed to comply. Female gender and older age were associated with maintaining compliance during the two study periods. In conclusion, compliance with dietary guidelines is a dynamic status, and only a small fraction of the population achieves sustained compliance with at least three guidelines. Almost two thirds of the population never achieve compliance with three guidelines

Low birth weight and markers of inflammation and endothelial activation in adulthood: The ARIC study

To investigate the hypothesis that intrauterine growth restriction might produce a longstanding pro-inflammatory tendency, we investigated the association of low birth weight with blood levels of markers of inflammation and endothelial activation in middle-aged adults

Red Blood Cell Transfusion Need for Elective Primary Posterior Lumbar Fusion in A High-Volume Center for Spine Surgery

(1) Background: This study evaluated the perioperative red blood cell (RBC) transfusion need and determined predictors for transfusion in patients undergoing elective primary lumbar posterior spine fusion in a high-volume center for spine surgery. (2) Methods: Data from all patients undergoing spine surgery between 1 January 2014 and 31 December 2016 were reviewed. Patients' demographics and comorbidities, perioperative laboratory results, and operative time were analyzed in relation to RBC transfusion. Multivariate logistic regression analysis was performed to identify the predictors of transfusion. (3) Results: A total of 874 elective surgeries for primary spine fusion were performed over the three years. Only 54 cases (6%) required RBC transfusion. Compared to the non-transfused patients, transfused patients were mainly female (p = 0.0008), significantly older, with a higher ASA grade (p = 0.0002), and with lower pre-surgery hemoglobin (HB) level and hematocrit (p < 0.0001). In the multivariate logistic regression, a lower pre-surgery HB (OR (95% CI) 2.84 (2.11-3.82)), a higher ASA class (1.77 (1.03-3.05)) and a longer operative time (1.02 (1.01-1.02)) were independently associated with RBC transfusion. (4) Conclusions: In the instance of elective surgery for primary posterior lumbar fusion in a high-volume center for spine surgery, the need for RBC transfusion is low. Factors anticipating transfusion should be taken into consideration in the patient's pre-surgery preparation

Tecnologias digitais móveis: reterritorialização dos cotidianos escolares

As tecnologias digitais móveis têm engendrado práticas reterritorializantes, a partir das quais os interagentes/praticantes têm criado espaços/tempos outros para ser, estar, criar e viver. O cotidiano escolar também vem sendo marcado intensamente pelas táticas de seus interagentes/praticantes que criam territorialidades outras a partir dessas tecnologias. Em vista disso, buscamos refletir sobre os movimentos ocorridos nos cotidianos escolares a partir da chegada das tecnologias digitais móveis em três escolas públicas do ensino fundamental. Para tanto, desenvolvemos uma cartografia dos processos que envolvem o fenômeno, descrevendo e buscando encontrar/identificar suas intensidades. Como resultados da pesquisa, apontamos a criação de territórios onde o digital passa a ser estruturante de práticas de produção de conteúdos, conhecimentos e significados e de reorganização do espaço escolar

Metabolic syndrome in overweight children from the city of Botucatu - São Paulo State - Brazil: agreement among six diagnostic criteria

<p>Abstract</p> <p>Background</p> <p>The metabolic syndrome has been described in children; however, a standard criterion has not been established for its diagnosis. Also, few studies have been conducted to specifically observe the possible existence of agreement among the existing diagnostic criteria. The purpose of the study is to evaluate agreement concerning prevalence rates of the metabolic syndrome diagnosed by six different criteria in overweight schoolchildren in the city of Botucatu - SP -Brazil.</p> <p>Methods</p> <p>This is a cross-sectional study on 128 overweight schoolchildren. Clinical examination included anthropometry, pubertal staging evaluation, and blood pressure. Triacylglycerol, glycemia, HDL-cholesterol, insulin levels, and HOMA-IR were determined. The Kappa index, the Mann-Whitney test and the chi-square test were used for statistical analysis.</p> <p>Results</p> <p>The prevalence of the metabolic syndrome varied from 10 to 16.5% according to different diagnostic criteria. Results were similar for boys and girls and pubertal stage. Great agreement was observed among the six different diagnostic criteria for the metabolic syndrome.</p> <p>Conclusions</p> <p>Different diagnostic criteria, when adopted for subjects with similar demographic characteristics, generate similar and compatible prevalence. Results suggest that it is possible to adopt any of the analyzed criteria, and the choice should be according to the components available for each situation.</p