An association study on contrasting cystic fibrosis endophenotypes recognizes KRT8 but not KRT18 as a modifier of cystic fibrosis disease severity and CFTR mediated residual chloride secretion

<p>Abstract</p> <p>Background</p> <p>F508del-CFTR, the most frequent disease-causing mutation among Caucasian cystic fibrosis (CF) patients, has been characterised as a mutant defective in protein folding, processing and trafficking. We have investigated the two neighbouring cytokeratin genes <it>KRT8 </it>and <it>KRT18 </it>in a candidate gene approach to ask whether variants in <it>KRT8 </it>and/or <it>KRT18 </it>modify the impaired ion conductance known as the CF basic defect, and whether they are associated with correct trafficking of mutant CFTR and disease severity of CF.</p> <p>Methods</p> <p>We have selected contrasting F508del-<it>CFTR </it>homozygous patient subpopulations stratified for disease severity, comparing 13 concordant mildly affected sib pairs vs. 12 concordant severely affected sib pairs, or manifestation of the CF basic defect in intestinal epithelium, comparing 22 individuals who exhibit CFTR-mediated residual chloride secretion vs. 14 individuals who do not express any chloride secretion, for an association. The <it>KRT8</it>/<it>KRT18 </it>locus was initially interrogated with one informative microsatellite marker. Subsequently, a low density SNP map with four SNPs in KRT8 and two SNPs in KRT18, each selected for high polymorphism content, was used to localize the association signal.</p> <p>Results</p> <p><it>KRT8</it>, but not <it>KRT18</it>, showed an association with CF disease severity (P_best= 0.00131; P_corr= 0.0185) and CFTR mediated residual chloride secretion (P_best= 0.0004; P_corr= 0.0069). Two major four-marker-haplotypes spanning 13 kb including the entire <it>KRT8 </it>gene accounted for 90% of chromosomes, demonstrating strong linkage disequilibrium at that locus. Absence of chloride secretion was associated with the recessive haplotype 1122 at rs1907671, rs4300473, rs2035878 and rs2035875. The contrasting haplotype 2211 was dominant for the presence of CFTR mediated residual chloride secretion. In consistency, the <it>KRT8 </it>haplotype 2211 was associated with mild CF disease while 1122 was observed as risk haplotype. Analysis of microsatellite allele distributions on the SNP background suggests that the mild <it>KRT8 </it>haplotype 2211 is phylogenetically older than its severe counterpart.</p> <p>Conclusions</p> <p>The two opposing <it>KRT8 </it>alleles which have been identified as a benign and as a risk allele in this work are likely effective in the context of epithelial cell differentiation. As the mild <it>KRT8 </it>allele is associated with CFTR mediated residual chloride secretion among F508del-<it>CFTR </it>homozygotes, the KRT8/KRT18 heterodimeric intermediary filaments of the cytoskeleton apparently are an essential component for the proper targeting of CFTR to the apical membrane in epithelial cells.</p

Evidence-based Kernels: Fundamental Units of Behavioral Influence

This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior–influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of its components would render it inert. Existing evidence shows that a variety of kernels can influence behavior in context, and some evidence suggests that frequent use or sufficient use of some kernels may produce longer lasting behavioral shifts. The analysis of kernels could contribute to an empirically based theory of behavioral influence, augment existing prevention or treatment efforts, facilitate the dissemination of effective prevention and treatment practices, clarify the active ingredients in existing interventions, and contribute to efficiently developing interventions that are more effective. Kernels involve one or more of the following mechanisms of behavior influence: reinforcement, altering antecedents, changing verbal relational responding, or changing physiological states directly. The paper describes 52 of these kernels, and details practical, theoretical, and research implications, including calling for a national database of kernels that influence human behavior

Standardization of relative centrifugal forces in studies related to platelet-rich fibrin.

Platelet-rich fibrin (PRF), a second-generation platelet concentrate, has been the focus of intensive research endeavors over the past 2 decades. Over the years, however, numerous reports have inaccurately reported relative centrifugal force (RCF) values, which has caused considerable confusion in the field. Furthermore, the use of trade names such as leukocyte and platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF) has further confused many readers, since studies have not always used centrifugation parameters with equal rotor sizes, angulation of tubes, and/or tube design. This has led to considerable misperception in the report of relative centrifugal force. Herein is described necessary parameters pivotal for the future report of RCF in studies related to PRF, which include: 1) dimensions of the rotor (radius at the clot and end of the tube); 2) rotor angulation for the tube holder; 3) revolutions per minute (RPM) and time; 4) RCF value calculated at either the RCF-minimum, RCF-clot, or RCF-maximum; 5) composition and size of tubes used to produce PRF; and 6) centrifugation model used. This editorial aims to minimize confusion in the field and create more transparent research reporting RCF values in future studies

Systems to support health technology assessment (HTA) in member states of the European union with limited institutionalization of HTA

OBJECTIVES: The aim of this study was to support health technology assessment (HTA) capacity building in Member States of the European Union with limited experience or without institutionalized HTA. The main output is a Handbook on HTA Capacity Building. METHODS: The methods used were worldwide surveys of (i) HTA organizations, (ii) information management units, and (iii) HTA educational programs. The results of two surveys (i & ii) were combined with expert opinion to produce the Handbook on HTA Capacity Building. RESULTS: Survey of HTA organizations (n = 41, response rate 35 percent). Most of the organizations were established by the government (61 percent), and all were not-for-profit. Working on HTA (80.5 percent) and doing research (63.4 percent) were the main lines of activity. Survey on information management units (n = 23, response rate 23 percent). Most (74.2 percent) of the responding HTA agencies reported having personnel dedicated to HTA information services. Survey on HTA educational programs (n = 48, response rate 60 percent). In total, nine Master of Science (MSc) programs were identified (three MSc in HTA and six MSc in HTA-related areas). Handbook on HTA Capacity Building. A group of twenty experts from thirteen countries developed the handbook. It consists of nine chapters focusing on HTA institutional development (structural setup, work processes, and visibility). CONCLUSIONS: Setting up organizational structures and establishing effective HTA programs that guide key policy decisions is a challenging task. There are no standard models or pathways. 'One size fits all' is not a useful principle because of the wide systemic and cultural differences between countries. The Handbook on HTA Capacity Building includes approaches for overall institutional development, especially in formulating objectives, setting up structures, and defining work processe