ABSTRACT
INTRODUCTION: Evidence shows that some individuals with HIV or diabetes do not report their medical history to the dentist. Disclosure is important because these individuals can be at greater risk of oral disease. AIMS AND OBJECTIVES: The aim of this study is to provide greater understanding of why some individuals do not disclose HIV or diabetes to the dentist.Methods In-depth interviews were conducted with 20 participants (10 HIV & 10 diabetes) based around the participant's diagnosis and disclosure history. Data were analysed using framework analysis. RESULTS: While a lack of disclosure can be found among those with a diagnosis of HIV and diabetes, it appears that the reasons behind disclosure, or lack thereof, are different for each. The reasons are based around: differences in age, understanding of diagnosis, experience of stigma, past disclosure behaviour, trust in dentists and experience of healthcare. Few individuals had discussed the effects of their diagnosis with their dentist or were advised on the importance of seeing a dentist. DISCUSSION: Individuals with chronic illness should be advised why it is important for the dentist to know their medical history and should be made to feel comfortable to disclose.
Subject(s)
Dentist-Patient Relations , Diabetes Mellitus/psychology , HIV Seropositivity/psychology , Self Disclosure , Adult , Age Factors , Female , Humans , Interviews as Topic , Male , Middle Aged , Qualitative Research , Stereotyping , Trust , Young AdultABSTRACT
This paper describes the design and characterization of novel inhibitors of IleRS, whose binding affinity approaches the tightest reported for noncovalent inhibition. Compounds were designed from a binding model for the natural product pseudomonic acid-A (PS-A) together with a detailed understanding of the reaction cycle of IleRS and characterization of the mode of binding of the reaction intermediate IleAMP. The interactions of the compounds with IleRS were characterized by inhibition of aminoacylation of tRNA or PP(i)/ATP exchange at supersaturating substrate concentration and by transient kinetics and calorimetry methods. A detailed understanding of the interaction of a comprehensive series of compounds with IleRS allowed the identification of key features and hence the design of exquisitely potent inhibitors. Predictions based on these results have been recently supported by a docking model based on the crystal structure of IleRS with PS-A [Silvian, L. F., Wang J. M., and Steitz T. A. (1999) Science 285 1074-1077].
Subject(s)
Anti-Bacterial Agents/chemistry , Enzyme Inhibitors/chemical synthesis , Isoleucine-tRNA Ligase/antagonists & inhibitors , Isoleucine-tRNA Ligase/chemistry , Models, Molecular , Mupirocin/chemistry , Anti-Bacterial Agents/metabolism , Binding Sites , Calorimetry, Differential Scanning , Circular Dichroism , Enzyme Inhibitors/metabolism , Enzyme Stability , Isoleucine/chemistry , Isoleucine/metabolism , Isoleucine-tRNA Ligase/metabolism , Kinetics , Models, Chemical , Mupirocin/metabolism , Spectrometry, Fluorescence , Staphylococcus aureus/enzymology , Structure-Activity Relationship , ThermodynamicsABSTRACT
The interactions of isoleucyl-tRNA synthetase (IleRS, E) from Staphylococcus aureus with both intermediate analogues and pseudomonic acid (PS-A) have been investigated using transient and steady-state techniques. Non-hydrolyzable analogues of isoleucyl-AMP (I) were simple competitive inhibitors (Ile-ol-AMP, Ki = 50 nM and Ile-NHSO2-AMP, Ki = 1 nM;). PS-A (J) inhibits IleRS via a slow-tight binding competitive mechanism where E.J (Kj = approximately 2 nM), undergoes an isomerization to form a stabilized E*.J complex (K*j = 50 pM). To overcome tight-binding artifacts when K*j << [E], K*j values were estimated from PPi/ATP exchange where [S] >> Km, thus raising K*j,app well above [E]. Using [3H]PS-A, it was confirmed that binding occurs with 1:1 stoichiometry and is reversible. Formation of inhibitor complexes was monitored directly through changes in enzyme tryptophan fluorescence. For Ile-ol-AMP and Ile-NHSO2-AMP, the fluorescence intensity of E.I was identical to that when E.Ile-AMP forms catalytically. Binding of PS-A induced only a small change in IleRS fluorescence that was characterized using transient kinetic competition. SB-205952, a PS-A analogue, produced a 37% quenching of IleRS fluorescence upon binding as a result of radiationless energy transfer. Inhibitor reversal rates were obtained by measuring relaxation between spectroscopically different complexes. Together, these data represent a comprehensive solution to the kinetics of inhibition by these compounds.
