Evaluation of treatment with pentamidine for cutaneous leishmaniasis in Suriname.

BACKGROUND: In Suriname, pentamidine isethionate (PI) is the only drug available for the treatment of cutaneous leishmaniasis (CL). Recently, local dermatologists have observed an increase in CL patients not responding adequately to the standard doses. METHODS: In this study, patient compliance to PI treatment was assessed, and its efficacy was evaluated by comparing the clinical criteria and parasitologic load in week 3 of treatment. Skin biopsies were collected before, during and at the end of therapy and tested by quantitative nucleic acid sequence-based amplification. RESULTS: In total, 67 patients with suspected CL were enrolled during the recruitment period, of which only 23 patients with confirmed CL were followed until the end of treatment. All 23 patients were found to be infected with Leishmania (Viannia) guyanensis. A lower cure rate (76-78%) was estimated than that obtained previously (90%), and only 50% of the recruited CL patients finished the complete treatment schedule. CONCLUSIONS: As one-half of the CL patients were treated insufficiently, a much shorter treatment protocol should be considered to improve the inadequate follow-up.

Comparison between quantitative nucleic acid sequence-based amplification, real-time reverse transcriptase PCR, and real-time PCR for quantification of Leishmania parasites.

DNA or RNA amplification methods for detection of Leishmania parasites have advantages regarding sensitivity and potential quantitative characteristics in comparison with conventional diagnostic methods but are often still not routinely applied. However, the use and application of molecular assays are increasing, but comparative studies on the performance of these different assays are lacking. The aim of this study was to compare three molecular assays for detection and quantification of Leishmania parasites in serial dilutions of parasites and in skin biopsies collected from cutaneous leishmaniasis (CL) patients in Manaus, Brazil. A serial dilution of promastigotes spiked in blood was tested in triplicate in three different runs by quantitative nucleic acid sequence-based amplification (QT-NASBA), quantitative real-time reverse transcriptase PCR (qRT-PCR), and quantitative real-time PCR (qPCR). In addition, the costs, durations, and numbers of handling steps were compared, and 84 skin biopsies from patients with suspected CL were tested. Both QT-NASBA and qRT-PCR had a detection limit of 100 parasites/ml of blood, while qPCR detected 1,000 parasites/ml. QT-NASBA had the lowest range of intra-assay variation (coefficients of variation [CV], 0.5% to 3.3%), while qPCR had the lowest range of interassay variation (CV, 0.4% to 5.3%). Furthermore, qRT-PCR had higher r2 values and amplification efficiencies than qPCR, and qPCR and qRT-PCR had faster procedures than QT-NASBA. All assays performed equally well with patient samples, with significant correlations between parasite counts. Overall, qRT-PCR is preferred over QT-NASBA and qPCR as the most optimal diagnostic assay for quantification of Leishmania parasites, since it was highly sensitive and reproducible and the procedure was relatively fast.

Use of horseradish peroxidase- and fluorescein-modified cisplatin derivatives for simultaneous labeling of nucleic acids and proteins.

BACKGROUND: Microarray platforms will change immunochemical and nucleic acid-based analysis of cell homogenates and body fluids compared with classic analyses. Microarrays use labeled target and immobilized probes, rather than fixed targets and labeled probes. We describe a method for simultaneous labeling of nucleic acids and proteins. METHODS: Horseradish peroxidase- and fluorescein-modified cisplatin derivatives were used for labeling of nucleic acids and proteins. These reagents, called the Universal Linkage System (ULS), bind to sulfur- and nitrogen-donor ligands present in amino acids and nucleotides. For automated screening of proteins and nucleic acids on microarrays, it is advantageous to label these biomolecules without pre- or postpurification procedures. The labeling of antibodies and nucleic acids in whole serum was therefore pursued. RESULTS: Immunoglobulins in nonpurified serum were labeled efficiently enough to be used for immunochemistry. To investigate whether protein-adapted labeling allowed nucleic acid labeling as well, 1 microg of plasmid DNA was added to 1 microL of serum. DNA and serum proteins were simultaneously labeled, and this labeled DNA could be used as a probe for direct fluorescence in situ hybridization. CONCLUSION: ULS provides a direct labeling tool for the (simultaneous) modification of proteins and nucleic acids even in unpurified samples.