The cytokine-dependent MUTZ-3 cell line as an in vitro model for the screening of contact sensitizers

Langerhans cells (LC) are key mediators of contact allergenicity in the skin. However, no in vitro methods exist which are based on the activation process of LC to predict the sensitization potential of chemicals. In this study, we have evaluated the performances of MUTZ-3, a cytokine-dependent human monocytic cell line, in its response to sensitizers. First, we compared undifferentiated MUTZ-3 cells with several standard human cells such as THP-1, KG-1, HL-60, K-562, and U-937 in their response to the strong sensitizer DNCB and the irritant SDS by monitoring the expression levels of HLA-DR, CD54, and CD86 by flow cytometry. Only MUTZ-3 and THP-1 cells show a strong and specific response to sensitizer, while other cell lines showed very variable responses. Then, we tested MUTZ-3 cells against a wider panel of sensitizers and irritants on a broader spectrum of cell surface markers (HLA-DR, CD40, CD54, CD80, CD86, B7-H1, B7-H2, B7-DC). Of these markers, CD86 proved to be the most reliable since it detected all sensitizers, including benzocaine, a classical false negative in local lymph node assay (LLNA) but not irritants. We confirmed the MUTZ-3 response to DNCB by real-time PCR analysis. Taken together, our data suggest that undifferentiated MUTZ-3 cells may represent a valuable in vitro model for the screening of potential sensitizers.     

Progressive familial intrahepatic cholestasis

Progressive familial intrahepatic cholestasis (PFIC) is an important cause of cholestatic liver disease and biliary cirrhosis in pediatric population. Three cases of PFIC are described that were diagnosed on the basis of family history, pruritus, cirrhosis and / or paucity of interlobular bile ducts on liver biopsy and presence of extrahepatic biliary tree on imaging. These patients were initially labeled as suffering from extra-hepatic biliary atresia and neonatal hepatitis. PFIC-1 and 2 could not be differentiated on histological grounds, since these patients presented late and process of fibrosis was advanced.     

Development of a rapid HPLC method for determination of famotidine in human plasma using a monolithic column

A rapid and sensitive HPLC method using a monolithic column has been developed for quantification of famotidine in plasma. The assay enables the measurement of famotidine for therapeutic drug monitoring with a minimum detectable limit of 5 ngml(-1). The method involves simple, one-step extraction procedure and analytical recovery was complete. The separation was carried out in reversed-phase conditions using a Chromolith Performance (RP-18e, 100 mm x 4.6 mm) column with an isocratic mobile phase consisting of 0.03 M disodium hydrogen phosphate buffer-acetonitrile (93:7, v/v) adjusted to pH 6.5. The wavelength was set at 267 nm. The calibration curve was linear over the concentration range 20-400 ngml(-1). The coefficients of variation for inter-day and intra-day assay were found to be less than 8%.     

A rapid HPLC method for the determination of losartan in human plasma using a monolithic column

A rapid and simple high-performance liquid chromatography (HPLC) method using a monolithic column has been developed for quantification of losartan (CAS 12450-98-8) in plasma. The assay enables the measurement of losartan for therapeutic drug monitoring. The method involves a simple, one-step extraction procedure. The analytical recovery was complete. The separation was carried out in reversed-phase conditions using a Chromolith Performance (RP-18e, 100 x 4.6 mm) column with an isocratic mobile phase consisting of 0.01 mol/L disodium hydrogen phosphate buffer-acetonitrile (60:40 v/v) adjusted to pH 3.5. The wavelength was set at 254 nm. Thioridazine (CAS 50-52-2) was used as internal standard. Losartan, thioridazine and the EXP 3174, the active metabolite of losartan, appeared 3.4, 5.0 and 10.5 min post injection, respectively. The calibration curve was linear over the concentration range 5-300 ng mL(-1) with a minimum detectable limit of 2 ng mL(-1). The coefficients of variation for the inter-day and intra-day assay were found to be less than 8 %. The applicability of this method for pharmacokinetic studies in humans was demonstrated. The present assay is rapid, simple, precise, and accurate and is suitable for pharmacokinetic studies.     

A simple and rapid HPLC method for the determination of atorvastatin in human plasma with UV detection and its application to pharmacokinetic studies

A rapid and sensitive high-performance liquid chromatographic method for the determination of atorvastatin (CAS 134523-00-5) in plasma was developed in this study. Atorvastatin was isolated from plasma using protein precipitation by acetonitrile. Diltiazem (CAS 33286-22-5) was used as internal standard. The chromatographic conditions were as follows: analytical 125 x 4 mm (i.d.) Nucleosil C8 column (5 microm particle size), mobile phase consisting of sodium dihydrogen phosphate buffer-acetonitrile (60:40, v/v) adjusted to pH 5.5 at a flow rate of 1.5 ml/min, UV detection at 245 nm. The detection limit for atorvastatin in plasma was 1 ng ml(-1). The calibration curve was linear over the concentration range 20-800 ng ml(-1). The recovery was complete. The inter-day and intra-day assay coefficients of variation were found to be less than 7%. The present validated method was successfully used for pharmacokinetic studies of atorvastatin in human subjects.     

Simultaneous determination of amoxicillin and clavulanic acid in human plasma by isocratic reversed-phase HPLC using UV detection

A simple, rapid and sensitive isocratic reversed phase HPLC method with UV detection using internal standard has been developed and validated for simultaneous determination of amoxicillin and clavulanic acid in human plasma. The assay enables the measurement of amoxicillin and clavulanic acid for therapeutic drug monitoring with a minimum quantification limit of 15 and 30 ng ml(-1), respectively. The method involves simple, one-step extraction procedure and analytical recovery was complete. The separation was carried out in reversed-phase conditions using a Chromolith Performance (RP-18e, 100 mm x 4.6mm) column with an isocratic mobile phase consisting of 0.02 M disodium hydrogen phosphate buffer-methanol (96:4, v/v) adjusted to pH 3.0. The wavelength was set at 228 nm. The coefficients of variation for inter-day and intra-day assay were found to be less than 9.0%.