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Lena Danielsson,1,2 Gunnvald Kvarstein,1,2 Svein Bergvik3 1Pain Clinic, Division Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø, Norway; 2Department of Clinical Medicine, UiT - the Arctic University of Norway, Tromsø, Norway; 3Department of Psychology, UiT the Arctic University of Norway, Tromsø, NorwayCorrespondence: Lena DanielssonPain Clinic, Division Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø NO-9038, NorwayTel +4799023564Email Lena.Danielsson@unn.noPurpose: Chronic pain is often multifactorial and accompanied by psychological distress, catastrophizing thoughts, reduced physical function, and socio-economic worries. In this explorative study, we investigated potential mediators in the relationships of psychological and demographic variables with chronic pain and physical function in women and men.Patients and Methods: The study included 301 patients admitted to a multidisciplinary pain clinic. Prior to their first consultation, patients completed a questionnaire including items on demographics (age, education, occupational and financial situation), catastrophizing thoughts, psychological distress, pain intensity, and physical function. Hierarchical multiple regression analyses examined demographic and psychological factors associated with pain intensity and physical function. Mediation and reversed mediation models were tested and developed based on calculated relations in the regression analyses between demographic, psychological, pain intensity and physical function variables.Results: Fifty-eight percent were females and mean age 43.8 and 46.0 years for women and men, respectively. In the regression analyses, psychological factors accounted better for pain intensity than demographic variables, while physical function was best accounted for by demographic variables. Among women, catastrophizing thoughts mediated significantly the relationships between education and pain intensity, and between education and physical function. Psychological distress mediated significantly the relationships between financial situation and pain intensity, and between financial situation and physical function in women. In men, the only significant mediation model was psychological distress mediating the relationship between financial situation and pain intensity. Some of the reversed models revealed indirect effects, indicating bidirectionality.Conclusion: The results indicate that there might be gender-specific mediators in how demographic variables are associated with pain intensity and physical function. This suggests an awareness among clinicians of potential gender-specific factors mediating pain problems, and the need for a gender-specific, multidisciplinary approach in the treatment of chronic pain.Keywords: depression, physical disability, comorbidity, catastrophizing, mediation, multidisciplinary treatment

Two independent methods for determination of the effectively sampled mass per unit area are presented and compared. The first method combines directional-hemispherical transmittance and reflectance measurements. A three-flux approximation of the equation of radiative transfer is used, to separately determine the specific absorption and scattering coefficients of the powder material, which subsequently are used to determine the effective sample size. The second method uses a number of diffuse reflectance measurements on layers of controlled powder thickness in an empirical approach. The two methods are shown to agree well and thus confirm each other. From the determination of the effective sample size at each measured wavelength in the visible-NIR region for two different model powder materials, large differences was found, both between the two analyzed powders and between different wavelengths. As an example, the effective sample size ranges between 15 and 70 mg/[cm.sup.2] for microcrystalline cellulose and between 70 and 300 mg/[cm.sup.2] for film-coated pellets. However, the contribution to the spectral information obtained from a certain layer decreases rapidly with increasing distance from the powder surface. With both methods, the extent of contribution from various depths of a powder sample to the visible - NIR diffuse reflection signal is characterized. This information is valuable for validation of analytical applications of diffuse reflectance visible - NIR spectrometry.

A model chemical reaction was monitored with in situ Fourier transform mid-infrared spectroscopy using an attenuated total reflectance probe. The evaluation of the IR spectra is complicated by the fact that the reaction runs in nonisothermal aqueous solution with large variations in pH. Despite this, it was possible to extract large amounts of useful information on the reaction after suitable pretreatment of the spectra. Alternating least-squares (ALS) multivariate curve resolution is shown to be a useful technique for obtaining pure component spectra and concentrations if suitable spectral regions are analyzed. Rank mapping methods are used as the basis for this sectioning into smaller regions. Techniques for finding and analyzing selective spectral regions are also shown to be applicable to this type of data. Partial least-squares (PLS) regression models based on spectral data were used to verify the results where possible. The correlation between the concentrations predicted from PLS and ALS is excellent.

Objective. Estimation of the glomerular filtration rate (GFR) is essential when evaluating patients with kidney disease and treating patients with drugs eliminated from the circulation by the kidneys. Cystatin C has been shown in several studies to be superior to creatinine in the estimation of GFR. At our hospitals, there is an increasing demand for cystatin C and at present we perform approximately 1500 cystatin C analyses a month. We thus need the assay available 24 h/day and to have it on our routine chemistry instrument to minimize handling time per test and time to reported test results. Material and methods. We have evaluated a new cystatin C immunoassay from Gentian (Gentian, Moss, Norway) on Architect ci8200 (Abbott Laboratories, Abbott Park, Ill., USA). A prerequisite at our hospital is that cystatin C results are reported as a calculated GFR in mL/min/1.73 m2, so we also made a comparison with iohexol clearance. Results. The Gentian cystatin C assay showed good agreement with the corresponding assay from Dade Behring (Deerfield, Ill., USA) and good inter-laboratory concordance. The assay has very low total imprecision, good linearity and strong correlation with iohexol clearance (R 2 = 0.956). The equation for the correlation curve is: y = 79.901x-1.4389. Conclusions. There was low inter-laboratory variation between the three laboratories involved in the cystatin C evaluation, and thus all three laboratories can use the same equation for calculating the estimated GFR. [ABSTRACT FROM AUTHOR]