Linearly scaling computation of ddPCM solvation energy and forces using the fast multipole method

This paper proposes the first linear scaling implementation for the domain decomposition approach of the polarizable continuum model (ddPCM) for the computation of the solvation energy and forces. The ddPCM-equation consists of a (non-local) integral equation on the van der Waals or solvent accessible surface of the solute's cavity resulting in a dense solution matrix, and, in turn, one matrix-vector multiplication has a quadratic arithmetic complexity with respect to the number of atoms of the solute molecule. The use of spherical harmonics as basis functions makes it natural to employ the fast multipole method (FMM) in order to provide an asymptotically linear scaling method. In this paper, we employ the FMM in a non-uniform manner with a clusterization based on a recursive inertial bisection. We present some numerical tests illustrating the accuracy and scaling of our implementation.

Universal indirect enzyme-linked immunosorbent assay for monitoring of human and animal brucellosis in Kazakhstan

Combinations of conventional serological methods and new ELISA procedures were evaluated to develop the most efficient and effective diagnostics for the detection of brucellosis in humans and animals. Sera from humans (n=249) and animals (n=99) were collected from brucellosis endemic areas (Zhambyl district and Enbekshi-Kazakh district of Almaty region in Kazakhstan) for serologic analysis. Sera from the humans reacted positively in the RBT (38.5%), SAT (43.3%), iELISA (42.5%) while sera from the animals reacted positively in RBT (79.8%), SAT (89.9%), CF (87.8%), iELISA (100%). Greater seropositivity was detected in animals as compared to human samples. All positive sera were also evaluated on an indirect ELISA (iELISA). Bacterial isolation was attempted on seropositive human sera. Our data indicate that the combination of conventional serological tests (SAT and CF), combined with the iELISA is optimal for the processing of large numbers of samples and the most efficient detection of human and animal brucellosis.

Growth of human-human hybridomas in serum-free media enhances antibody secretion

Human-human hybridomas derived from fusing lymph node lymphocytes with UC 729-6 were adapted to grow in commercially available serum-free medium and were compared with serum-supplemented [10% fetal bovine serum (FBS)] cultures. Over a 6-d period, no significant changes occurred in the growth of the cells in 10% FBS or serum-free medium. In cultures supplemented with 10% FBS more total proteins were secreted than in serum-free cultures. However, there was an enhanced secretion of three- to four-fold of both immunoreactive human IgG and IgM under serum-free conditions compared to serum-supplemented conditions. Serum-free conditions may provide the appropriate milieu for the increased level of Ig secretion from human hybridomas derived from UC 729-6 in that there are no inhibitors that may be present in serum.

The generation of Ig-secreting UC 729-6 derived human hybridomas by electrofusion

UC 729-6, a 6-thioguanine resistant human lymphoblastoid B cell line, was fused with human lymphocytes by electrofusion. Resulting human-human hybridomas were tetraploid, expressed markers derived from both fusion parents, and secreted approximately 1 microgram Ig/10(6) cells/ml/day. Cells to be used for electrofusion were washed in 0.3M mannitol, and fusions were performed with glass slides, 1.0 ml, and 50.0 ml chambers. Fusion sequences consisted of alignment, compression, and the fusion event itself. The optimal cell concentration for electrofusion was 5 X 10(6)/ml. Fusion efficiencies of human lymphocytes were ranked as follows: lymphoma cells greater than lymph node lymphocytes greater than PBL. 80% of the lymphoma hybridomas, 60% of the lymph node hybridomas, and 40% of the PBL hybridomas were Ig secretors. These data demonstrate that the UC 729-6 cell line is a suitable vector for generating human-human hybridomas by electrofusion.