The present invention relates to a metabolic biomarker set for use in assessing breast cancer in a mammalian subject. In particular, the invention relates to a metabolic biomarker set for screening and/or diagnosing breast cancer, the metabolic biomarker set including at least (a) one amino acid selected from glutamine, glutamate and serine, and one lipid, or (b) glutamine and glutamate. Further, the invention relates to a metabolic biomarker set for prediction of therapeutic response to breast cancer neoadjuvant chemotherapy. Moreover, the present invention relates to a method for assessing breast cancer, which includes obtaining a biological sample, preferably blood, from a mammalian subject and measuring in the biological sample the amount and/or ratios of metabolites. By employing the specific biomarkers and the method according to the present invention it becomes possible to more properly and reliably assess breast cancer.

The disclosure generally relates to the detection of symmetrical dimethylarginine (SDMA). More particularly, the disclosure relates to the detection of SDMA using a solid phase. The disclosure provides devices, reagents, kits and methods for detecting symmetrical dimethyl arginine (SDMA) in sample, such as a biological sample from an animal. The method includes detecting the presence or amount of SDMA in the sample by using an immunoassay format, such as a competitive immunoassay. The assay includes the use of antibodies to SDMA that are specific for SDMA and that have less affinity for other arginine derivatives.

A method and a sensor for detecting L-arginine are provided. The method includes synthesizing ferrocene-functionalized hexadecapeptide dithiocyclopentane (FC-P16 Peptide), preparing a polypeptide composite membrane-modified electrode (FC-P16 Peptide/AuE), detecting L-Arg and other steps. The results show that the polypeptide composite membrane-modified electrode (FC-P16 Peptide/AuE) exhibits excellent electrochemical response properties to L-Arg. In 10 mmol/L phosphate-buffered saline (PBS, pH=7.4), the DPV response peak current of the polypeptide composite membrane-modified electrode has an excellent linear relationship with the L-Arg concentration of 1.0×10.sup.−13 mol/L to 1.0×10.sup.−7 mol/L, with a detection limit of 1.0×10.sup.−13 mol/L. With prominent reproducibility, repeatability and selectivity, the modified electrode has potential application in life science and nutritional health.

The present invention relates to the field of biochemistry, more particularly to proteomics, more particularly to protein sequencing, even more particularly to single molecule peptide sequencing. The invention discloses methods for single molecule protein sequencing and/or amino acid identification using cleavage inducing agents which are not specific for one particular amino acid, cleave polypeptides step by step from the N-terminus onwards and provide information on the identity of the cleaved amino acids based on the reaction kinetics.

The present invention relates to systems, kits, and methods for identifying subjects with increased levels of phenylacetyl glutamine (PAG) or the combination of PAG and trimethylamine-n-oxide (TMAO) and/or N6-trimethyl-lysine (TML), and/or PSA, pp and/or betaine, and/or choline, as well as methods of determining risk of disease (e.g., CVD, heart failure, asthma, diabetes, thrombosis, and lethal prostate cancer) based on such levels. In certain embodiments, the subjects are free of chronic kidney disease and/or have type II diabetes. In particular embodiments, subjects are treated with a therapeutic, such as a beta-adrenergic blocking agent, an alpha 2 adrenergic receptor agonist, an alpha 2 adrenergic receptor antagonist, an antibiotic or antibiotic cocktail, or a prostate cancer therapeutic. In certain embodiments, the subject is treated with a procedure such as brachytherapy, radiation therapy, or prostatectomy.

The present invention relates to a specific set of circulating biomarkers and related methods and kits for the diagnosis of Brugada Syndrome in a human being.

The present invention relates to a method for determining the origin of glutamic acid in a sample and, in a broader sense, relates to a method for determining the origin of an amino acid. The present invention makes it possible to measure the stable isotope ratio, with a considerably higher accuracy than that of conventional methods, by measuring the δ13C of glutamic acid (amino acid) by elemental analysis-stable isotope ratio mass spectrometry (EA-IRMS) and measuring the δ15N by gas chromatography-stable isotope ratio mass spectrometry (GC-IRMS). In addition, the present invention makes it possible to determine the origin of glutamic acid (amino acid) by comparing the stable isotope ratio of the glutamic acid (amino acid) whose origin is unclear with the stable isotope ratio of glutamic acid (amino acid) whose origin is clear.

Provided herein chiral derivatization reagents for use in separating and detecting of amine containing enantiomers. The said chiral derivatization reagents provide a combination of improved detectable properties to facilitate various downstream analyses. In particular, the chiral derivatization reagents include at least one chiral carbon atom; at least one strongly basic moiety; at least one chromophore moiety or at least one fluorophore moiety; and at least one reactive group. The present disclosure further provides methods for analyzing amine-containing enantiomeric isomers using a chromatographic separation device and a mass spectroscopy.

The present invention relates to compositions and methods for determining the absolute configuration of D/L-cysteine and/or the enantiomeric composition of cysteine and/or the concentration of total cysteine in a sample. Uses of the composition and method are also described.

The present invention provides markers for judging the efficacy of therapy with a PD-1 signal inhibitor before or at an early stage of the therapy. As biomarkers for predicting or judging the efficacy of therapy with a PD-1 signal inhibitor, surrogate indicators of metabolic changes relating to mitochondrial activity in T cells and/or T cell activation in a subject are used. As such indicators, intestinal flora-related metabolites in the serum or plasma, energy metabolism-related metabolites in the serum or plasma, amino acid metabolism-related metabolites and/or derivatives thereof in the serum of plasma, oxygen consumption rate and/or ATP turnover in peripheral blood CD8.sup.+ cells, amino acids in T cells, and T-bet in peripheral blood CD8.sup.+ cells may be used.