ABSTRACT
PURPOSE: The objective of this study was to assess the utility of a fourth-generation multi-theory model (MTM) in explaining the intention for initiation and sustenance of PAP adherence among newly diagnosed sleep apnea patients. PATIENTS AND METHODS: For this cross-sectional study, data were collected at a private sleep center located in the Southeastern United States. A total of 138 newly diagnosed patients with sleep apnea who had been prescribed PAP therapy completed a valid and reliable 41-item MTM instrument. Stepwise multiple regression modeling was conducted to assess MTM based explanatory variables of PAP adherence in this study sample. RESULTS: MTM constructs namely participatory dialogue (ß = 0.17, p = 0.014), behavioral confidence (ß = 0.48, p < 0.001), and changes in the physical environment (ß = 0.26, p = 0.001) were statistically significant predictors of the intention for initiation of PAP therapy and accounted for 53.5% of the variance. Emotional transformation (ß = 0.57, p < 0.001), changes in the social environment (ß = 0.16, p = 0.016), and practice for change (ß = 0.16, p = 0.047) were statistically significant predictors of the intention for sustenance of PAP therapy and accounted for 60.6% of the variance. CONCLUSION: The MTM was found to be a promising theoretical model in explaining the intention for initiation and sustenance of PAP therapy.
ABSTRACT
Background: Phosphoprotein phosphatases (PPP) belong to the PPP Sequence family, which in turn belongs to the broader metallophosphoesterase (MPE) superfamily. The relationship between the PPP Sequence family and other members of the MPE superfamily remains unresolved, in particular what transitions took place in an ancestral MPE to ultimately produce the phosphoprotein specific phosphatases (PPPs). Methods: We use structural and sequence alignment data, phylogenetic tree analysis, sequence signature (Weblogo) analysis, in silico protein-peptide modeling data, and in silico mutagenesis to trace a likely route of evolution from MPEs to the PPP Sequence family. Hidden Markov Model (HMM) based iterative database search strategies were utilized to identify PPP Sequence Family members from numerous bacterial groups. Results: Using Mre11 as proxy for an ancestral nuclease-like MPE we trace a possible evolutionary route that alters a single active site substrate binding His-residue to yield a new substrate binding accessory, the "2-Arg-Clamp". The 2-Arg-Clamp is not found in MPEs, but is present in all PPP Sequence family members, where the phosphomonesterase reaction predominates. Variation in position of the clamp arginines and a supplemental sequence loop likely provide substrate specificity for each PPP Sequence family group. Conclusions: Loss of a key substrate binding His-in MPEs opened the path to bind novel substrates and evolution of the 2-Arg-Clamp, a sequence change seen in both bacterial and eukaryotic phosphoprotein phosphatases.General significance: We establish a likely evolutionary route from nuclease-like MPE to PPP Sequence family enzymes, that includes the phosphoprotein phosphatases.
