Transplantation of bone marrow mononuclear cells modulates hippocampal expression of growth factors in chronically epileptic animals.

AIMS: In previous studies, transplantation of bone marrow mononuclear cells (BMMCs) in epileptic animals has been found to be neuroprotective. However, the mechanism by which the BMMCs act remains unclear. We hypothesize that BMMCs may provide neuroprotection to the epileptic brain through trophic support. To test our hypothesis, we studied the temporal expression of neurotrophins after BMMC transplantation in the epileptic rat hippocampus. METHODS: Chronically epileptic rats were intravenously transplanted with 1 × 10(7) BMMCs isolated from GFP transgenic mice. Expression levels of BDNF, GDNF, NGF, VEGF, and TGF-ß1, and their receptors, were evaluated by ELISA and/or qRT-PCR analysis. RESULTS: Our data revealed increased protein expression of BDNF, GDNF, NGF, and VEGF and reduced levels of TGF-ß1 in the hippocampus of transplanted epileptic animals. Additionally, an increase in the mRNA expression of BDNF, GDNF, and VEGF, a reduction in TGF-ß1, and a decrease in mRNA levels of the TrkA and TGFR-ß1 receptors were also observed. CONCLUSION: The gain provided by transplanted BMMCs in the epileptic brain may be related to the ability of these cells in modulating the network of neurotrophins and angiogenic signals.

Real time PCR quantification of viable Mycobacterium tuberculosis from sputum samples treated with propidium monoazide.

Diagnostic methods of TB, nowadays, are prone to delay in diagnosis, increased false negative results and are not sensitive to many forms of paucibacillary disease. The aims of this study were to implement a quantitative nucleic acid-based diagnostic test for paucibacillary tuberculosis, enabling the identification and quantification of viable Mycobacterium tuberculosis bacilli by quantitative Real-Time PCR (qRT-PCR). The intergenic region of the single-copy inhA-mabA gene was chosen as the target region for design of primers and probes conjugated with fluorophores. The construction of synthetic DNA flanking the target region served as standards for absolute quantification of nucleic acids. Using the intercaling dye, propidium monoazide, we were able to discriminate between viable and dead cells of M. tuberculosis. The diagnosis method showed a broad sensitivity (96.1%) when only compared to samples of smear-positive sputum and ROC analyses shows that our approach performed well and yielded a specificity of 84.6% and a sensitivity of 84.6% when compared to M. tuberculosis colony-forming units counting.

The shielding effect of glycerol against protein ionization in electrospray mass spectrometry.

Most commercial recombinant proteins used as molecular biology tools, as well as many academically made preparations, are generally maintained in the presence of high glycerol concentrations after purification to maintain their biological activity. The present study shows that larger proteins containing high concentrations of glycerol are not amenable to analysis using conventional electrospray ionization mass spectrometry (ESI-MS) interfaces. In this investigation the presence of 25% (v/v) glycerol suppressed the signals of Taq DNA polymerase molecules, while 1% (v/v) glycerol suppressed the signal of horse heart myoglobin. The signal suppression was probably caused by the interaction of glycerol molecules with the proteins to create a shielding effect that prevents the ionization of the basic and/or acidic groups in the amino acid side chains. To overcome this difficulty the glycerol concentration was decreased to 5% (v/v) by dialyzing the Taq polymerase solution against water, and the cone voltage in the ESI triple-quadrupole mass spectrometer was set at 80-130 V. This permitted observation of a mass spectrum that contained ions corresponding to protonation of up to 50% of the ionizable basic groups. In the absence of glycerol up to 85% of the basic groups of Taq polymerase became ionized, as observed in the mass spectrum at relatively low cone voltages. An explanation of these and other observations is proposed, based on strong interactions between the protein molecules and glycerol. For purposes of comparison similar experiments were performed on myoglobin, a small protein with 21 basic groups, whose ionization was apparently suppressed in the presence of 1% (v/v) glycerol, since no mass spectrum could be obtained even at high cone voltages.