Zoekresultaten

Rapid chemoenzymatic route to glutamate transporter inhibitor l -TFB-TBOA and related amino acids

The complex amino acid (l-threo)-3-[3-[4-(trifluoromethyl)benzoylamino]benzyloxy]aspartate (l-TFB-TBOA) and its derivatives are privileged compounds for studying the roles of excitatory amino acid transporters (EAATs) in regulation of glutamatergic neurotransmission, animal behavior, and in the pathogenesis of neurological diseases. The wide-spread use of l-TFB-TBOA stems from its high potency of EAAT inhibition and the lack of off-target binding to glutamate receptors. However, one of the main challenges in the evaluation of l-TFB-TBOA and its derivatives is the laborious synthesis of these compounds in stereoisomerically pure form. Here, we report an efficient and step-economic chemoenzymatic route that gives access to enantio- and diastereopure l-TFB-TBOA and its derivatives at multigram scale.

Amino acid profiling from fingerprints

UPLC-MS is a commonly used technique to first separate complex samples and subsequently quantify molecules of interest. Herein we describe the use of UPLC-MS using an amide stationary phase to quantify non-derivatized amino acids extracted from fingerprints. As detector either a triple-quadrupole MS/MS or a TOF-MS detector was used. This method allows for a simple and fast sample preparation, which facilitates the analysis of large amounts of samples.

Review of Presence, Induction and Isolation of Major Cellular Constituents From Porphyra Sensu Lato (Rhodophyceae), Including Mycosporine-Like Amino Acids (MAA’s)

Seaweeds from the genus Porphyra play a big economic role in seaweed aquaculture, mainly in Asia. In Europe, resources are put towards seaweed cultivation, but without attention to the Porphyra species which is also native to Europe. Different nomenclature and specifications are used to describe Porphyra, due to taxonomical reclassification and difficult phenotypical identification. Abiotic & biotic together with seasonal factors make for major variance in chemical compositions that are reported. This is also fueled by differences in chemical analytical methods and procedures followed. Combining taxonomical challenges, variance due to seasonal factors and differences in analysis, overviewing published research on Porphyra constituents such as protein, polysaccharides and fatty acids is warranted. Within this review, cellular consitutents found in Porphyra are discussed, including proteins, polysaccharides, fatty acids and mycosporine-like amino acids (MAA’s). MAA's are considered amongst the strongest UV-photoprotectants found in nature and feature possible applications in cosmetics. As global interest in seaweeds as food, feed and industrial resource is emerging, opportunities for Porphyra constituents is rising.

Analysis of amino acid enantiomers from aged fingerprints

Fingerprints found at a crime scene can be key in criminal investigations. A method to accurately determine the age of the fingerprint, potentially crucial to linking the fingerprint to the crime, is not available at the moment. In this paper, we show that the use of the enantiomeric ratio of d/l-serine in fingerprints could pose as interesting target for age estimation techniques. We developed a UPLC-MS/MS method to determine the enantiomer ratios of histidine, serine, threonine, alanine, proline, methionine and valine from fingerprint residue. We found a significant change only in the relative ratio of d-serine with increasing fingerprint age after analysis of fingerprints up to 6 months old.

Achieving protein targets without energy overfeeding in critically ill patients: A prospective feasibility study

Background & aims: High protein delivery during early critical illness is associated with lower mortality, while energy overfeeding is associated with higher mortality. Protein-to-energy ratios of traditional enteral formulae are sometimes too low to reach protein targets without energy overfeeding. This prospective feasibility study aimed to evaluate the ability of a new enteral formula with a high protein-to-energy ratio to achieve the desired protein target while avoiding energy overfeeding.Methods: Mechanically ventilated non-septic patients received the high protein-to-energy ratio nutrition during the first 4 days of ICU stay (n = 20). Nutritional prescription was 90% of measured energy expenditure. Primary endpoint was the percentage of patients reaching a protein target of ≥1.2 g/kg ideal body weight on day 4. Other endpoints included a comparison of nutritional intake to matched historic controls and the response of plasma amino acid concentrations. Safety endpoints were gastro-intestinal tolerance and plasma urea concentrations. Results: Nineteen (95%) patients reached the protein intake target of ≥1.2 g/kg ideal body weight on day 4, compared to 65% in historic controls (p = 0.024). Mean plasma concentrations of all essential amino acids increased significantly from baseline to day 4. Predefined gastro-intestinal tolerance was good, but unexplained foul smelling diarrhoea occurred in two patients. In one patient plasma urea increased unrelated to acute kidney injury. Conclusions: In selected non-septic patients tolerating enteral nutrition, recommended protein targets can be achieved without energy overfeeding using a new high protein-to-energy ratio enteral nutrition.

Amino acid profiling from fingerprints, a novel methodology using UPLC-MS