A rapid purification method for trace amounts of cell-free DNA in urine

Cell-free DNA (cfDNA) is a valuable biomarker for the early detection of genetic diseases and for evaluating treatment efficacy. We developed a rapid and cost-effective purification method for urinary cfDNA using a commercially available DNA purification kit. This method enables the rapid purification (< 20 min) of DNA suitable for use in the polymerase chain reaction (PCR) using only a centrifuge and a heater. Additionally, we discovered that short-chain DNA could be efficiently purified by incorporating a concentration step using cationic particles. Quantitative PCR (qPCR) analysis of the purified DNA demonstrated that use of the developed method effectively decreased the DNA detection limit. Overall, this method enables the rapid and inexpensive purification of DNA, and it is suitable for combination with recent advanced DNA analysis technologies such as qPCR, next-generation sequencing, and mass spectrometry. It is therefore expected to contribute to the early detection of cancer and have a major impact on the medical field.

Evaluation of thumbnail clipping as a specimen for retrospectively assessing average production of testosterone

BACKGROUND

The chronic abnormal production of testosterone (T) is associated with many disorders in men. Fingernail clippings might be more suited for the diagnosis and medium-to-long term therapeutic monitoring for the T-related chronic disorders than the blood-derived specimens. The objective of this study was to characterize a thumbnail clipping as the specimen for assessing the several months-old T status.

METHODS

Thumbnail clippings from various subjects were analyzed by liquid chromatography/electrospray ionization-tandem mass spectrometry to evaluate the gender difference, and changes caused by aging and androgen deprivation therapy (ADT) in the thumbnail T concentration.

RESULTS

There was an evident gender difference in the thumbnail T concentrations [male; 2.55 ± 0.85 ng/g and female; 0.48 ± 0.29 ng/g, mean ± SD (n = 25 each), Welch t-test]. The thumbnail T concentrations significantly decreased with age in men (n = 268, Scheffé F-test), which was similar to those of the free or bioavailable T in serum/plasma. The thumbnail T concentrations sharply decreased by a 6-months ADT (especially the effect of the luteinizing hormone-releasing hormone agonist/antagonist) for patients with prostate cancer (n = 10).

CONCLUSIONS

The thumbnail clipping can be a specimen to retrospectively assess the average T production.

Indirect Enantioseparations: Recent Advances in Chiral Metabolomics for Biomedical Research

Chiral metabolomics is starting to become a well-defined research field, powered by the recent advances in separation techniques. This review aimed to cover the most relevant advances in indirect enantioseparations of endogenous metabolites that were published over the last 10 years, including improvements and development of new chiral derivatizing agents, along with advances in separation methodologies. Moreover, special emphasis is put on exciting advances in separation techniques combined with mass spectrometry, such as chiral discrimination by ion-mobility mass spectrometry together with untargeted strategies for profiling of chiral metabolites in complex matrices. These advances signify a leap in chiral metabolomics technologies that will surely offer a solid base to better understand the specific roles of enantiomeric metabolites in systems biology.

Biomarkers of disease in human nails: a comprehensive review

Diagnostic, monitoring, response, predictive, risk, and prognostic biomarkers of disease are all widely studied, for the most part in biological fluids or tissues, but there is steadily growing interest in alternative matrices such as nails. Here we comprehensively review studies dealing with molecular or elemental biomarkers of disease, as opposed to semiological, pharmacological, toxicological, or biomonitoring studies. Nails have a long history of use in medicine as indicators of pathological processes and have also been used extensively as a matrix for monitoring exposure to environmental pollution. Nail clippings are simple to collect noninvasively as well as to transport and store, and the matrix itself is relatively stable. Nails incorporate, and are influenced by, circulating molecules and elements over their several months of growth, and it is widely held that markers of biological processes will remain in the nail, even when their levels in blood have declined. Nails thus offer the possibility to not only look back into a subject's metabolic history but also to study biomarkers of processes that operate over a longer time scale such as the post-translational modification of proteins. Reports on ungual biomarkers of metabolic and endocrine diseases, cancer, and psychological and neurological disorders will be presented, and an overview of the sampling and analytical techniques provided.

The Recent Advances of Fluorescent Sensors Based on Molecularly Imprinted Fluorescent Nanoparticles for Pharmaceutical Analysis

Fluorescent nanoparticles have good chemical stability and photostability, controllable optical properties and larger stokes shift. In light of their designability and functionability, the fluorescent nanoparticles are widely used as the fluorescent probes for diverse applications. To enhance the sensitivity and selectivity, the combination of the fluorescent nanoparticles with the molecularly imprinted polymer, i.e. molecularly imprinted fluorescent nanoparticles (MIFN), was an effective way. The sensor based on MIFN (the MIFN sensor) could be more compatible with the complex sample matrix, which was especially widely adopted in medical and biological analysis. In this mini-review, the construction method, detective mechanism and types of MIFN sensors are elaborated. The current applications of MIFN sensors in pharmaceutical analysis, including pesticides/herbicide, veterinary drugs/drugs residues and human related proteins, are highlighted based on the literature in the recent three years. Finally, the research prospect and development trend of the MIFN sensor are forecasted.

DL-Amino Acid Analysis Based on Labeling with Light and Heavy Isotopic Reagents Followed by UPLC-ESI-MS/MS

L-Pyroglutamic acid succinimidyl ester (L-PGA-OSu) and its isotopic variant (L-PGA[d₅]-OSu) were synthesized and used as the chiral labeling reagents for the enantioseparation of amino acids by reversed-phase UPLC-ESI-MS/MS. The enantiomers of amino acids were labeled with the reagents at 60 °C for 10 min in an alkaline medium. The resulting diastereomers were well separated by the reversed-phase chromatography using an ODS column, packed with small particles (1.7 μm) (Rs = 1.95-8.05). A highly sensitive detection at a low-fmol level (0.5-3.2 fmol) was obtained from the selected reaction monitoring (SRM) chromatograms. An isotope labeling strategy using light and heavy variants for the differential analysis of the DL-amino acids in different sample groups is also presented in this paper. The ratios of D/L-alanine in different yogurt products were successfully determined by the proposed method. The D/L ratios were almost comparable to those obtained from only using light reagent (i.e., L-PGA-OSu). Therefore, the proposed strategy seems to be useful for the differential analysis of DL-amino acids, not only in food products but also in biological samples.

Chiral Metabolomics Using Triazine-Based Chiral Labeling Reagents by UPLC-ESI-MS/MS

The determination of enantiomers of biological molecules is an important issue because a significant difference in the activity of the enantiomers is generally observed in biological systems. Chiral separations can be carried out by direct resolution using a chiral stationary column or by indirect resolution based on the derivatization with a chiral reagent. Many chiral-labeling reagents for ultraviolet-visible and fluorescence detections have been developed for various functional groups, such as amine and carboxylic acid. However, there are hardly any labeling reagents for LC-MS-specific detection. Based on this observation, we have developed several chiral-labeling reagents for LC-MS/MS analysis.This chapter describes methodologies and applications for the indirect LC-MS/MS determination of biological chiral molecules using triazine-based chiral-labeling reagents, i.e., (S and R)-1-(4,6-dimethoxy-1,3,5-triazin-2-yl)pyrrolidin-3-amine (DMT-3(S and R)-Apy) for carboxylic acids and (S and R)-2,5-dioxopyrrolidin-1-yl-1-(4,6-dimethoxy-1,3,5-triazin-2-yl)pyrrolidine-2-carboxylate (DMT-(S and R)-Pro-OSu) for amines and amino acids. A reliable method for the non-targeted chiral metabolomics is also described in this chapter.

The great importance of normalization of LC-MS data for highly-accurate non-targeted metabolomics

The non-targeted metabolomics analysis of biological samples is very important to understand biological functions and diseases. LC combined with electrospray ionization-based MS has been a powerful tool and widely used for metabolomic analyses. However, the ionization efficiency of electrospray ionization fluctuates for various unexpected reasons such as matrix effects and intraday variations of the instrument performances. To remove these fluctuations, normalization methods have been developed. Such techniques include increasing the sensitivity, separating co-eluting components and normalizing the ionization efficiencies. Normalization techniques allow simultaneously correcting of the ionization efficiencies of the detected metabolite peaks and achieving quantitative non-targeted metabolomics. In this review paper, we focused on these normalization methods for non-targeted metabolomics by LC-MS.