Experimental Validation of Comprehensive Calculation for High-Resolution Linear MALDI-TOF Mass Spectrometry.

This work discusses the effectiveness of the previously developed comprehensive calculation model to optimize linear MALDI-TOF mass spectrometers. The model couples space- and velocity-focusing to precisely analyze the flight-time distribution of ions and predict optimal experimental parameters for the highest mass resolving power. Experimental validation was conducted using a laboratory-made instrument to analyze CsI and angiotensin I ions in low to medium / range.

High-performance miniature linear time-of-flight mass spectrometry as an advantageous tool in a high mass-to-charge range.

A miniature matrix-assisted laser desorption/ionization linear time-of-flight mass spectrometer suitable for the high mass-to-charge (/) region is described. The instrument size is roughly 1/50th that of regular instruments, and detailed dimensions and experimental parameters were optimized based on the comprehensive calculation method to provide satisfactory mass resolving power. Observations showed that the performance is limited in the low / range and becomes comparable with that of regular instruments in the mid / range.

A Dynamic Data Correction Method for Enhancing Resolving Power of Integrated Spectra in Spectroscopic Analysis.

A dynamic data correction method embedded in the process of data acquisition improves spectral quality. The method minimizes the impact of random errors in spectroscopic measurements by correcting peak positions in every single-scan spectrum. The method is fast enough to facilitate online data correction.

[MicroRNA-155 induces macrophage polarization to M1 in infection].

Objective: To investigate microRNAs differential expression and polarization of human macrophages in infection.

Methods: The microRNAs differential expression of human macrophages in infection was analyzed by microarray, and further validated by qRT-PCR. pEGFP-miR-155 was transfected into THP-1 cells by Lipofectamine M2000 and the transfection ratio was detected by flow cytometry.

Impact of uneven sample morphology on mass resolving power in linear MALDI-TOF mass spectrometry: A comprehensive theoretical investigation.

This work discusses the correlation between the mass resolving power of matrix-assisted laser desorption/ionization time-of-flight mass analyzers and extraction condition with an uneven sample morphology. Previous theoretical calculations show that the optimum extraction condition for flat samples involves an ideal ion source design and extraction delay. A general expression of spectral feature takes into account ion initial velocity, and extraction delay is derived in the current study.

Reducing Spatial Heterogeneity of MALDI Samples with Marangoni Flows During Sample Preparation.

This work demonstrates a method to prepare homogeneous distributions of analytes to improve data reproducibility in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Natural-air drying processes normally result in unwanted heterogeneous spatial distributions of analytes in MALDI crystals and make quantitative analysis difficult. This study demonstrates that inducing Marangoni flows within drying droplets can significantly reduce the heterogeneity problem.

A neutralization charge detection method for detecting ions under ambient and liquid-phase conditions.

The neutralization charge detection method detects induction signals produced from the neutralization of electric charges of ions at metal surfaces. The signals are intense and can propagate through phase boundaries for detection. The detection method can detect ions under ambient and liquid-phase conditions with high sensitivity and fast response time.

Coupled Space- and Velocity-Focusing in Time-of-Flight Mass Spectrometry-a Comprehensive Theoretical Investigation.

A comprehensive theoretical calculation that couples space- and velocity-focusing is developed for optimizing the design of a time-of-flight (TOF) mass spectrometer. Conventional designs for ion sources of TOF mass spectrometers deviate from the optimal condition because the velocity- and space-focusing conditions are considered separately for two ions with simplified equations. The result of a reexamination taking into account all essential ions reveals that the conventional ion source design, especially the length of the ion extraction region, results in poor resolving power.

Activated microglia contribute to neuronal apoptosis in Toxoplasmic encephalitis.

Background: A plethora of evidence shows that activated microglia play a critical role in the pathogenesis of the central nervous system (CNS). Toxoplasmic encephalitis (TE) frequently occurs in HIV/AIDS patients. However, knowledge remains limited on the contributions of activated microglia to the pathogenesis of TE.

Comparative studies of macrophage-biased responses in mice to infection with Toxoplasma gondii ToxoDB #9 strains of different virulence isolated from China.

Background: Different from three clonal lineages of Toxoplasma gondii in North America and Europe, the genotype China 1 is predominantly prevalent in China. However, there are different virulent isolates within China 1, such as virulent TgCtwh3 and avirulent TgCtwh6, and little is known about differences in macrophage activation between them. The objective of this study focused on cytokine production, phenotype and markers of activated macrophages, and correlated signaling pathway induced by the two isolates.

Preventive effect of pidotimod on reactivated toxoplasmosis in mice.

As one of food-borne parasitic diseases, toxoplasmosis entails the risk of developing reactivation in immunocompromised patients. The synthetic dipeptide pidotimod is a potent immunostimulating agent that improves the immunodefenses in immunodepression. To investigate the efficacy of pidotimod as a preventive treatment, we used a murine model of reactivated toxoplasmosis with cyclophosphamide (CY)-induced immunosuppression.

Abrogation of functional selectin-ligand expression reduces migration of pathogenic CD8+ T cells into heart.

CD8+ T cells are involved in autoimmune and infectious myocarditis and cardiac allograft rejection. The role of selectins in cardiac recruitment of CD8+ T cells is not understood. In this study, the contribution of T cell selectin ligands to effector CD8+ T cell recruitment into the heart was examined using a model of myocarditis, which depends on transfer of OVA peptide-specific CD8+ T cells (OT-I) into mice (CMy-mOva) that express OVA in the heart.

Increased blood myeloid dendritic cells and dendritic cell-poietins in Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH), previously known as histiocytosis X, is a reactive proliferative disease of unknown pathogenesis. Current therapies are based on nonspecific immunosuppression. Because multiple APCs, including Langerhans cells and macrophages, are involved in the lesion formation, we surmised that LCH is a disease of myeloid blood precursors.