Psychological factors associated with diabetes self-management among adolescents with Type 1 diabetes: A systematic review.

This review aims to synthesise the literature examining the psychosocial variables related to self-management (insulin adherence, non-adherence and administration, blood sugar monitoring, dietary behaviour, exercise behaviour) in adolescents with type 1 diabetes. A systematic search of three electronic databases was carried out and, after the application of eligibility criteria, 21 articles were assessed for quality prior to data extraction. Numerous psychological factors were found to be associated with self-management; however, correlations were typically small to moderate. The strongest associations were found between social anxiety and diet (among males); greater intrinsic motivation, conscientiousness and diet; and extraversion and exercise.

Assessing the fidelity of delivery of an intervention to increase attendance at the English Stop Smoking Services.

BACKGROUND: Implementation fidelity refers to the extent to which a proposed intervention is enacted as designed and is necessary to determine how much the intervention in question is the primary mechanism in any changes observed. Start2quit was a randomised controlled trial that aimed to improve attendance at the English Stop Smoking Service (SSS). The complex intervention combining computer-tailored personal risk letters and no-commitment ("taster") sessions aimed at encouraging attendance at the SSS doubled attendance at the SSS and significantly increased abstinence rates, although attendance and abstinence varied between participating SSSs. Assessment of the fidelity of the delivery of the taster sessions to the protocol was embedded into the trial and is the focus of this study. METHODS: Eighteen SSSs participated in the study. Taster sessions were delivered by SSS advisors in the area. Of the 131 sessions delivered, 93 (71 %) were recorded and 41 (31.3 %) were selected for transcription and analysis. The taster session protocol contained 73 specified behaviours, which were independently classified into component behaviour change techniques (BCTs) using an established taxonomy for smoking cessation. All transcripts were coded by two authors with 25 % additionally coded by a third. The fidelity of each taster session was expressed as the percentage of overall protocol-specified behaviours that were delivered. Adherence to each BCT was measured as the number of behaviours applied by the advisors within each BCT divided by the total number classified within each. RESULTS: Adherence of protocol-specified behaviours was relatively high (median 71.23 %), though there was considerable variation (28.76 to 95.89 %) in individual sessions. Median fidelity to specific BCTs across sessions also varied from 50 to 100 %. Shorter sessions, sessions run jointly by two advisors, by female advisors, or by advisors aged 45 to 54 were associated with higher levels of adherence. There was no association between adherence and subsequent attendance at the SSS. CONCLUSIONS: These results suggest that the delivery of the intervention of this study is not likely to have been impacted by issues of fidelity. As such, we can have greater confidence that variability in the main outcome is not due to variability in SSS advisor adherence to the protocol of the taster sessions. TRIAL REGISTRATION: Current Controlled Trials ISRCTN76561916.

Photocontrol of beta-amyloid peptide (1-40) fibril growth in the presence of a photosurfactant.

The effect of an azobenzene-based photoresponsive surfactant on fibril formation of beta-amyloid (1-40) (Abeta40) has been studied using small-angle neutron scattering (SANS), atomic force microscopy (AFM), and light scattering (LS) measurements. Fibril formation is inhibited with a lag phase persisting for approximately 5 h in the presence of the trans isomer of the photosurfactant under visible light (i.e., the relatively hydrophobic, activated form). Conversely, only a 2-h lag phase is observed under UV light with the cis photosurfactant isomer (relatively hydrophilic, passive form), while large fibril networks are immediately observed for the pure protein. Furthermore, in situ UV illumination of a solution of trans surfactant and protein results in rapid fibril formation. Thus, the ability to photoreversibly inhibit and trigger the fibrilization process with light illumination is demonstrated. Shape-reconstruction analysis of the SANS data is used to obtain novel information on the conformation of the protein during the initial stages of protein aggregation. Small, cylindrical protein aggregates 5 nm in diameter and 7 nm long are initially observed during the lag phase independent of the sample conditions. AFM images confirm both the aggregate structure and the duration of the lag phase and further suggest that these early aggregates appear to be the nuclei for longer aggregates that develop over time.

Solution structure of an amyloid-forming protein during photoinitiated hexamer-dodecamer transitions revealed through small-angle neutron scattering.

Shape-reconstruction analysis applied to small angle neutron scattering (SANS) data is used to determine the in vitro conformations of alpha-chymotrypsin oligomers that form as a result of partial unfolding with a photoresponsive surfactant. In the presence of the photoactive surfactant under visible light, the native oligomers (dimers or compact hexamers) rearrange into expanded corkscrew-like hexamers. Converting the surfactant to the photopassive form with UV light illumination causes the hexamers to laterally aggregate and intertwine into dodecamers with elongated, twisted conformations containing cross-sectional dimensions similar to amyloid protofilaments. Secondary-structure measurements with FT-IR indicate that this photoinduced hexamer-to-dodecamer association occurs through intermolecular beta sheets stabilized with hydrogen bonds, similar to amyloid formation. Traditional structural characterization techniques such as X-ray crystallography and NMR are not easily amenable to the study of these non-native protein conformations; however, SANS is ideally suited to the study of these associated intermediates, providing direct observation of the mechanism of oligomeric formation in an amyloid-forming protein. Combined with photoinitiated hexamer-to-dodecamer associations in the presence of the photoresponsive surfactant, this study could provide unique insight into the amyloidosis disease pathway, as well as novel disease treatment strategies.

Probing lysozyme conformation with light reveals a new folding intermediate.

A means to control lysozyme conformation with light illumination has been developed using the interaction of the protein with a photoresponsive surfactant. Upon exposure to the appropriate wavelength of light, the azobenzene surfactant undergoes a reversible photoisomerization, with the visible-light (trans) form being more hydrophobic than the UV-light (cis) form. As a result, surfactant binding to the protein and, thus, protein unfolding, can be tuned with light. Small-angle neutron scattering (SANS) measurements were used to provide detailed information of the protein conformation in solution. Shape-reconstruction methods applied to the SANS data indicate that under visible light the protein exhibits a native-like form at low surfactant concentrations, a partially swollen form at intermediate concentrations, and a swollen/unfolded form at higher surfactant concentrations. Furthermore, the SANS data combined with FT-IR spectroscopic analysis of the protein secondary structure reveal that unfolding occurs primarily in the alpha domain of lysozyme, while the beta domain remains relatively intact. Thus, the surfactant-unfolded intermediate of lysozyme appears to be a separate structure than the well-known alpha-domain intermediate of lysozyme that contains a folded alpha domain and unfolded beta domain. Because the interactions between the photosurfactant and protein can be tuned with light, illumination with UV light returns the protein to a native-like conformation. Fluorescence emission data of the nonpolar probe Nile red indicate that hydrophobic domains become available for probe partitioning in surfactant-protein solutions under visible light, while the availability of these hydrophobic domains to the probe decrease under UV light. Dynamic light scattering and UV-vis spectroscopic measurements further confirm the shape-reconstruction findings and reveal three discrete conformations of lysozyme. The results clearly demonstrate that visible light causes a greater degree of lysozyme swelling than UV light, thus allowing for the protein conformation to be controlled with light.