An Improved Protocol for Efficient Engraftment in NOD/ LTSZ-SCIDIL-2RcNULL Mice Allows HIV Replication and Development of Anti-HIV Immune Responses

in PLoS ONE (2012), 7(6), 38491

Cord blood hematopoietic progenitor cells (CB-HPCs) transplanted immunodeficient NOD/LtsZ-scidIL2Rcnull (NSG) and NOD/SCID/IL2Rcnull (NOG) mice need efficient human cell engraftment for long-term HIV-1 ... [more ▼]

Cord blood hematopoietic progenitor cells (CB-HPCs) transplanted immunodeficient NOD/LtsZ-scidIL2Rcnull (NSG) and NOD/SCID/IL2Rcnull (NOG) mice need efficient human cell engraftment for long-term HIV-1 replication studies. Total body irradiation (TBI) is a classical myeloablation regimen used to improve engraftment levels of human cells in these humanized mice. Some recent reports suggest the use of busulfan as a myeloablation regimen to transplant HPCs in neonatal and adult NSG mice. In the present study, we further ameliorated the busulfan myeloablation regimen with fresh CB-CD34+cell transplantation in 3–4 week old NSG mice. In this CB-CD34+transplanted NSG mice engraftment efficiency of human CD45+cell is over 90% in peripheral blood. Optimal engraftment promoted early and increased CD3+T cell levels, with better lymphoid tissue development and prolonged human cell chimerism over 300 days. These humanized NSG mice have shown long-lasting viremia after HIV-1JRCSF and HIV-1Bal inoculation through intravenous and rectal routes. We also saw a gradual decline of the CD4+T cell count, widespread immune activation, up-regulation of inflammation marker and microbial translocation after HIV-1 infection. Humanized NSG mice reconstituted according to our new protocol produced, moderate cellular and humoral immune responses to HIV-1 postinfection. We believe that NSG mice reconstituted according to our easy to use protocol will provide a better in vivo model for HIV-1 replication and anti-HIV-1 therapy trials. [less ▲]

Improved Quantification of Angiogenesis in the Rat Aortic Ring Assay

in Angiogenesis (2001), 4(2), 133-42

In vitro angiogenesis assays are essential for the identification of potential angiogenic agents and screening for pharmacological inhibitors. Among these assays, the rat aortic ring model developed by ... [more ▼]

In vitro angiogenesis assays are essential for the identification of potential angiogenic agents and screening for pharmacological inhibitors. Among these assays, the rat aortic ring model developed by Nicosia bridges the gap between in vivo and in vitro models. The quantification of angiogenesis on this system must be applicable to characterise vascular networks of various states of complexity. We present here an improved computer-assisted image analysis which allows: (1) the determination of the aortic ring area and its factor shape; (2) the number of microvessels, the total number of branchings, the maximal microvessel length and the microvessel distribution; (3) the total number of isolated fibroblast-like cells and their distribution. We show that this method is suitable to quantify spontaneous angiogenesis as well as to analyse a complex microvascular network induced by various concentrations of vascular endothelial growth factor (VEGF). In addition, by evaluating a new parameter, the fibroblast-like cell distribution, our results show that: (1) during spontaneous angiogenic response, maximal fibroblast-like cell migration delimits microvascular outgrowth; and (2) the known angiogenic inhibitor Batimastat prevents endothelial cell sprouting without completely blocking fibroblast-like cell migration. Finally, this new method of quantification is of great interest to better understand angiogenesis and to test pro- or anti-angiogenic agents. [less ▲]

Improved rank-based dependence measures for categorical data

in Statistics & Probability Letters (2003), 63

We extend rank-based dependence measures like Spearman's rho to categorical data so that the same ±1 limits are always reached under complete dependence. A goodness-of-fit procedure is derived for ... [more ▼]

We extend rank-based dependence measures like Spearman's rho to categorical data so that the same ±1 limits are always reached under complete dependence. A goodness-of-fit procedure is derived for dependence models using copulas. [less ▲]

An Improved Reachability Analysis Method for Strongly Linear Hybrid Systems

in Lecture Notes in Computer Science (1997), 1254

This paper addresses the exact computation of the set of reachable states of a linear hybrid system. It proposes an approach that is an extension of classical state-space exploration. This approach uses a ... [more ▼]

This paper addresses the exact computation of the set of reachable states of a linear hybrid system. It proposes an approach that is an extension of classical state-space exploration. This approach uses a new operation, based on a cycle analysis in the control graph of the system, for generating sets of reachable states, as well as a powerful representation system for sets of values. The method broadens the range of hybrid systems for which a finite and exact representation of the set of reachable states can be computed. In particular, the state-space exploration may be performed even if the set of variable values reachable at a given control location cannot be expressed as a finite union of convex regions. The technique is illustrated on a very simple example. [less ▲]

Improved separation and quantification of dioxin and furan congeners using Novel low-bleed capillary gas chromatography columns and mass spectrometry

in Organohalogen Compounds (2004), 66

Improved separation of the 209 polychlorinated biphenyl congeners using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

in Journal of Chromatography. A (2004), 1040(2), 227-238

The separation of the 209 polychlorinated biphenyl (PCB) congeners has been studied using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS). Four ... [more ▼]

The separation of the 209 polychlorinated biphenyl (PCB) congeners has been studied using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS). Four column combinations based on thermally stable phases, DB-1/HT-8, DB-XLB/HT-8, DB-XLB/BPX-50, and HT-8/BPX-50, have been investigated. The HT-8/BPX-50 set produced the best separation. The distribution of the 100 to 150 ms wide peaks was highly structured in the chromatographic space and based on the degree of ortho-substitution within each separated homologue series. A total of 192 congeners were resolved in 146 min (1.3 analyte per min) using this column set. Eight coelutions involved 17 congeners. Among them, seven congeners were present in Aroclors at levels >1.0 wt.% (CBs 33, 47, 48, 95, 97, 163, 187). Except for CBs 47 and 48, none of the major constituents of commercial mixtures were coeluting. CB 138 was well separated from CBs 163 and 164 in the second dimension. For all column sets, CBs 20, 33, and 109 always coeluted with other PCBs. The 12 toxic dioxin-like congeners (CBs 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, 189), and the seven European Union marker PCBs (CBs 28, 52, 101, 118, 138, 153, 180) were separated from any interfering congeners. This was not the case for the other investigated column sets. [less ▲]

Improved stability and transient behaviour of generalized-alpha time integrators for constrained flexible systems

Conference (2011, November)

An Improved Test to Study the Changes in Membrane Permeability During Rehydration of Freeze-Dried Weissella paramesenteroides LC11

in The Open Biotechnology Journal (2010), 4

The objective of this study was to assess changes in membrane permeability during rehydration of freeze-dried Weissella paramesenteroides LC11. Viability was assessed using the electrical conductivity ... [more ▼]

The objective of this study was to assess changes in membrane permeability during rehydration of freeze-dried Weissella paramesenteroides LC11. Viability was assessed using the electrical conductivity measurement (ms cm-1 g-1 dry weight) and the plate count method (cfu g-1 dry weight). The symptoms of injury included an increase in the electrolyte leakage during the first 4 h of rehydration in Milli Q water and a decrease in the survival rate (about 64%), suggesting an increase in membrane permeability during dehydration. During rehydration of the freeze-dried strain, an increase in the temperature, NaCl or monosodium glutamate concentration and a decrease in H+ concentration resulted in an increase in the electrolyte leakage and a decrease in the survival rate (from about 5% to 97%, with respect to the treatment made). However, a decrease in the electrolyte leakage was observed with increasing glycerol, sucrose or maltodextrin and resulted in the maintenance of cell viability. Change in membrane permeability might lead to electrolyte leakage during rehydration and, ultimately, cell death. The electrolyte leakage assay associated with the plate count method, a quick and inexpensive method, could be used to evaluate dried bacteria resistance to dehydration. [less ▲]

Improved use of serial laboratory data in acute myocardial infarction

in Clinical Chemistry (1983), 28

An improved weighting method with multibounds formulation and convex programming for multicriteria structural optimization

in International Journal for Numerical Methods in Engineering (2001), 52(9), 889-902

This paper presents an improved weighting method for multicriteria structural optimization. By introducing artificial design variables, here called as multibounds formulation (MBF), we demonstrate ... [more ▼]

This paper presents an improved weighting method for multicriteria structural optimization. By introducing artificial design variables, here called as multibounds formulation (MBF), we demonstrate mathematically that the weighting combination of criteria can be transformed into a simplified problem with a linear objective function. This is a unified formulation for one criterion and multicriteria problems. Due to the uncoupling of involved criteria after the transformation, the extension and the adaptation of monotonic approximation-based convex programming methods such as the convex linearization (CONLIN) or the method of moving asymptotes (MMA)are made possible to solve multicriteria problems as efficiently as for one criterion problems. In this work, a multicriteria optimization tool is developed by integrating the multibounds formulation with the CONLIN optimizer and the ABAQUS finite element analysis system. Some numerical examples are taken into account to show the efficiency of this approach. [less ▲]