A validated method for quantitation of psilocin in plasma by LC–MS/MS and study of stability

A liquid chromatography-electrospray ionization/tandem mass spectrometry method for the quantitation of psilocin in plasma is presented. Sample workup was performed with mixed-mode solid-phase extraction using ascorbic acid and nitrogen for drying to protect the unstable analyte. Calibration curves were linear from 2 to 100?ng/mL, and no selectivity problems occurred. The limit of detection was 0.1?ng/mL, and the limit of quantitation was 0.34?ng/mL. Recovery was >86% and matrix effects were <110%. Both were reproducible. Interday and intraday precisions at different concentrations were 1.5-4.3% relative standard deviation, bias within ±9%. Processed samples were stable in the autosampler for at least 26?h. Furthermore, the stability of psilocin in blood stored at different temperatures over various periods of time was investigated. Samples stored at room temperature showed a continuous decrease of analyte leading to a loss of about 90% after 1?week. Storage in the fridge improved sample stability significantly. Freezing of blood samples led to a not reproducible loss of psilocin.     

Establishment of a new methicillin resistant staphylococcus aureus animal model of osteomyelitis

Purpose

The increase in methicillin-resistant Staphylococcus aureus (MRSA) infections is currently a major health care problem. Vancomycin is still often the first-line anti-microbiological agent for treating such infections; however, a recent decline in efficacy of vancomycin in MRSA infections has raised concerns and accelerated the search for new antibiotics. The aim of this study was to establish a MRSA peri-implant osteomyelitis animal model for future testing of new anti-microbiological agents under typical MRSA infection conditions.

Methods

Eighteen randomised NZW-rabbits underwent a standardised surgical procedure with the insertion of a femoral bone implant. Animals were then divided into group 1 (MRSA inoculation, no antibiotics; M/N), group 2 (MRSA inoculation, Vancomyin; M/V), and group 3 (no MRSA inoculation, no antibiotics; N/N). The primary study outcome parameters were animal leucocyte count, animal weight, and animal body temperature at one, seven, and 42 days after surgery. Additionally, a histo-morphometrical score was established and adjusted to a modified histological Smeltzer score.

Results

Macroscopic and histo-morphometrical findings showed a peri-implant osteomyelitis in group 1 with both increased acute and chronic infection parameters in M/N, as compared to M/V and N/N, indicating that vancomycin treatment prevented typical morphological changes of MRSA peri-implant osteomyelitis. Similarly, there was a reduction in animal weight and increase in leucocyte count and body temperature in group 1 (each p < 0.005). Vancomycin treatment again resulted in significantly reduced leucocyte count and body temperature, and increased animal body weight.

Conclusions

Here we have established a peri-implant MRSA osteomyelitis model that successfully combined clinical and laboratory outcome parameters of infection with histo-morphometrical results; this model appears to be valuable for future experimental use and therapeutic monitoring of new anti-microbiological MRSA drugs.     

The P2X7 receptor tracer [11C]SMW139 as an in vivo marker of neuroinflammation in multiple sclerosis: a first-in man study

European Journal of Nuclear Medicine and Molecular Imaging - The novel PET tracer [11C]SMW139 binds with high affinity to the P2X7 receptor, which is expressed on pro-inflammatory microglia. The...     

New Target Genes in Endometrial Tumors Show a Role for the Estrogen‐Receptor Pathway in Microsatellite‐Unstable Cancers

Microsatellite instability (MSI) in tumors results in an accumulation of mutations in (target) genes. Previous studies suggest that the profile of target genes differs according to tumor type. This paper describes the first genome‐wide search for target genes for mismatch repair‐deficient endometrial cancers. Genes expressed in normal endometrium containing coding repeats were analyzed for mutations in tumors. We identified 44 possible genes of which seven are highly mutated (>15%). Some candidates were also found mutated in colorectal and gastric tumors. The most frequently mutated gene, NRIP1 encoding nuclear receptor‐interacting protein 1, was silenced in an endometrial tumor cell line and expression microarray experiments were performed. Silencing of NRIP1 was associated with differences in the expression of several genes in the estrogen‐receptor network. Furthermore, an enrichment of genes related to cell cycle (regulation) and replication was observed. We present a new profile of target genes, some of them tissue specific, whereas others seem to play a more general role in MSI tumors. The high‐mutation frequency combined with the expression data suggest, for the first time, an involvement of NRIP1 in endometrial cancer development.     

CD4and CD8T-cell reactions against leukemia-associated- or minor-histocompatibility-antigens in AML-patients after allogeneic SCT

T-cells play an important role in the remission-maintenance in AML-patients (pts) after SCT, however the role of LAA- (WT1, PR1, PRAME) or minor-histocompatibility (mHag, HA1) antigen-specific CD4⁺ and CD8⁺T-cells is not defined.