Performance evaluation of mapping and linear imaging FTIR microspectroscopy for the characterisation of paint cross sections.

Different Fourier transform infrared microspectroscopic techniques, using attenuated total reflection (ATR) mode and single-element mercury-cadmium-telluride (MCT) detector (mapping) or multielement MCT detector (raster scanning), are compared with each other for the characterisation of inorganic compounds and organic substances in paint cross sections. All measurements have been performed on paint cross sections embedded in potassium bromide, a transparent salt in the mid-infrared region, in order to better identify the organic materials without the interference of the usual embedding resin. The limitations and advantages of the different techniques are presented in terms of spatial resolution, data quality and chemical information achieved. For all techniques, the chemical information obtained is found to be nearly identical. However, ATR mapping performed with a recently developed instrumentation shows the best results in terms of spectral quality and spatial resolution. In fact, thin organic layers (approximately 10 microm) have been not only identified but also accurately located. This paper also highlights the recent introduction of multielement detectors, which may represent a good compromise between mapping and imaging systems.

Patient-reported and physician-estimated adherence to HAART: social and clinic center-related factors are associated with discordance.

OBJECTIVES: To evaluate the rate of discordance between patients and physicians on adherence to highly active antiretroviral therapy (HAART) and identify factors related to discordance in these two assessments. DESIGN: Prospective, multicenter, cohort study (AdICONA) nested within the Italian Cohort Naive Antiretrovirals (ICONA) study. SETTING: Tertiary clinical centers. PARTICIPANTS: The patients filled out a 16-item self-administered questionnaire on adherence to HAART. At the same time, physicians estimated the current HAART adherence of their patient. MAIN OUTCOME MEASURE: Discordance between patient and physician on adherence to antiretroviral therapy. RESULTS: From May 1999 to March 2000, 320 paired patient-physician assessments were obtained. Patients had a mean plasma HIV RNA of 315 copies/ml (64% had undetectable HIV RNA) and a mean CD4+ cell count of 577 cells x 10(6)/L. Nonadherence was reported by 30.9% of patients and estimated by physicians in 45.0% cases. In 111 cases (34.7%), patients and physicians were discordant on adherence to HAART. Kappa statistics was 0.27. Using patient-assessed adherence as reference, sensitivity, specificity, positive predictive value, and negative predictive value of physician-estimated adherence were 64.7%, 66.6%, 81.2%, and 45.8%, respectively. On multivariable analysis, low education level, unemployment, absence of a social worker in the clinical center, and unavailability of afternoon visits were significantly correlated with patient-physician discordance on adherence to antiretrovirals. CONCLUSIONS: Physicians did not correctly estimate patient-reported adherence to HAART in more than one third of patients. Both social variables and factors related to the clinical center were important predictors of discordance between patients and physicians. Interventions to enhance adherence should include strategies addressed to improve patient-physician relationship.

Relative prognostic value of self-reported adherence and plasma NNRTI/PI concentrations to predict virological rebound in patients initially responding to HAART.

We studied the predictive value of self-reported adherence and plasma drug concentrations on virological rebound to HAART. Among 238 participants in the AdICoNA study who had viral load < or = 500 copies/ml, 42 (17.6%) experienced virological rebound by 96 weeks. Both self-reported non-adherence and sub-optimal concentration were independently associated with a higher risk of virological rebound.