Biphenylsulfonacetic acid inhibitors of the human papillomavirus type 6 E1 helicase inhibit ATP hydrolysis by an allosteric mechanism involving tyrosine 486

Human papillomaviruses (HPVs) are the causative agents of benign and malignant lesions of the epithelium. Despite their high prevalence, there is currently no antiviral drug for the treatment of HPV-induced lesions. The ATPase and helicase activities of the highly conserved E1 protein of HPV are essential for viral DNA replication and pathogenesis and hence are considered valid antiviral targets. We recently described novel biphenylsulfonacetic acid inhibitors of the ATPase activity of E1 from HPV type 6 (HPV6). Based on kinetics and mutagenesis studies, we now report that these compounds act by an allosteric mechanism. They are hyperbolic competitive inhibitors of the ATPase activity of HPV6 E1 and also inhibit its helicase activity. Compounds in this series can also inhibit the ATPase activity of the closely related enzyme from HPV11; however, the most potent inhibitors of HPV6 E1 are significantly less active against the type 11 protein. We identified a single critical residue in HPV6 E1, Tyr-486, substituted by a cysteine in HPV11, which is primarily responsible for this difference in inhibitor potency. Interestingly, HPV18 E1, which also has a tyrosine at this position, could be inhibited by biphenylsulfonacetic acid derivatives, thereby raising the possibility that this class of inhibitors could be optimized as antiviral agents against multiple HPV types. These studies implicate Tyr-486 as a key residue for inhibitor binding and define an allosteric pocket on HPV E1 that can be exploited for future drug discovery efforts.     

Virological and pharmacological parameters predicting the response to lopinavir-ritonavir in heavily protease inhibitor-experienced patients

The genotypic inhibitory quotient (GIQ) has been proposed as a way to integrate drug exposure and genotypic resistance to protease inhibitors and can be useful to enhance the predictivity of virologic response for boosted protease inhibitors. The aim of this study was to evaluate the predictivity of the GIQ in 116 protease inhibitor-experienced patients treated with lopinavir-ritonavir. The overall decrease in human immunodeficiency virus type 1 (HIV-1) RNA from baseline to month 6 was a median of -1.50 log(10) copies/ml and 40% of patients had plasma HIV-1 RNA below 400 copies/ml at month 6. The overall median lopinavir study-state C(min) concentration was 5,856 ng/ml. Using univariate linear regression analyses, both lopinavir GIQ and the number of baseline lopinavir mutations were highly associated with virologic response through 6 months. In the multivariate analysis, only lopinavir GIQ, baseline HIV RNA, and the number of prior protease inhibitors were significantly associated with response. When the analysis was limited to patients with more highly mutant viruses (three or more lopinavir mutations), only lopinavir GIQ remained significantly associated with virologic response. This study suggests that GIQ could be a better predictor of the virologic response than virological (genotype) or pharmacological (minimal plasma concentration) approaches used separately, especially among patients with at least three protease inhibitor resistance mutations. Therapeutic drug monitoring for patients treated by lopinavir-ritonavir would likely be most useful in patients with substantially resistant viruses.     

Late hemodynamic changes during a negative passive head-up tilt predict the symptomatic outcome to a nitroglycerin sensitized tilt

BACKGROUND: Sublingual nitroglycerin is advocated to sensitize the passive 70 degrees head-upright tilt test (HUTT) of patients with unexplained syncope. We hypothesized that a detailed analysis of hemodynamic responses recorded during a negative HUTT could predict the outcome to a subsequent nitroglycerin sensitized HUTT (NTG-HUTT). METHODS: Thirty-two patients (46 +/- 3 years, 17 males) with recurrent unexplained syncope but a negative HUTT were included. Heart rate, arterial blood pressure, and central hemodynamics assessed by transthoracic impedance (preejection and rapid left ventricular ejection time, slow ejection time, peak amplitude of first derivative, and cardiac index) were recorded during supine rest and 45 minutes HUTT. Changes from supine rest of the variables were retrospectively compared between patients with a negative (n = 15, NTG-HUTT(-)) and positive (n = 17, NTG-HUTT(+)) outcome to 10 minutes subsequent NTG-HUTT. RESULT: Significant differences between groups were observed during the 15th-20th minutes (Italian protocol) and during the last 5 minutes of passive HUTT (Westminster protocol). The combination of cutoff values, determined by receiver operating curves, on hemodynamic variables changes during the last 5 minutes predicted the outcome to a NTG-HUTT with a sensitivity of 76% and a specificity of 87%. The cutoff values determined during 15th-20th minutes gave an attractive sensitivity (85%) but a too weak specificity (53%) to shorten the 45 minutes passive HUTT at 20 minutes. CONCLUSION: Outcome to a NTG-HUTT can be reliably predicted by selected criteria determined from multiple hemodynamic variables recorded during a passive 70 degrees HUTT.     

Use of the Research Diagnostic Criteria for Temporomandibular Disorders for multinational research: translation efforts and reliability assessments in The Netherlands

AIMS: To outline the steps taken to conduct and to culturally adapt Dutch translations of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) history questionnaire, clinical examination form, and verbal instructions to the patients, and to assess the reliability of the clinical examination. METHODS: For the linguistic translation from English into Dutch, the forward and back-translation approach was followed. For cultural adaptation, an expert panel reviewed the translation, and a pretest was performed on a small clinical sample. Examiner training and calibration were carried out, and the clinical reliability of a "gold standard examiner" and 3 clinicians was assessed on 18 symptomatic TMD patients and 6 asymptomatic controls. The order of the examinations was based on a quasi-random Latin square design. Intraclass correlation coefficients (ICCs) were calculated to assess the overall interexaminer reliability of the clinical examination. RESULTS: A linguistically valid and culturally equivalent translation of the RDC/TMD into Dutch resulted from the above-outlined procedure. As for the clinical reliability, the ICC values obtained could mostly be considered "excellent" or, less frequently, as "fair to good." Poor reliability was found only for some of the palpation tests. For uncommon diagnoses (disc displacement without reduction and without limited mouth opening; osteoarthritis), no reliable ICC value could be calculated. CONCLUSION: The mode described by the authors for preparing clinical sites for RDC/TMD-based research is a feasible one.     

Effects of exercise adherence on physical function among overweight older adults with knee osteoarthritis

OBJECTIVE: To determine whether high exercise adherence improved physical function among older adults with knee osteoarthritis (OA) who were overweight or obese. METHODS: Associations between exercise adherence, changes in 6-minute walking distance in meters, and self-reported disability (Western Ontario and McMaster Universities Osteoarthritis Index function subscale) after 6 and 18 months were examined among an Arthritis, Diet, and Activity Promotion Trial subsample (n = 134) using multiple linear regression models. RESULTS: Higher exercise adherence was associated with greater improvements in 6-minute walking distance after 6 and 18 months and in disability after 6 months. Pain and body mass index (BMI) contributed, to some extent, to explaining the link between exercise adherence and changes in physical performance and self-reported disability. CONCLUSION: Higher exercise adherence is associated with improved physical function in overweight and obese older adults with knee OA. This indicates that promoting adherence is clinically relevant when prescribing exercise regimens that also focus on decreasing pain and BMI.