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Purpose: We aimed to describe the vitamin D status and its distribution in different age groups, sexes, seasons, and provinces of a large Chinese population. Methods: This study retrospectively analyzed 1,528,685 results of serum 25-hydroxyvitamin D (25(OH)D) in the central laboratory of KingMed Diagnostics. The samples were from the individuals aged 0–119 years old in 30 provinces of China. Serum 25(OH)D was measured by an accurate commercial liquid chromatography-tandem mass spectrometry (LC–MS/MS) method from January 2017 to December 2019. The subjects were stratified by age, sex, the season of blood collection, and the province of residence. Results: The median 25(OH)D concentration was 25.5 ng/mL (interquartile range (IQR) 18.7–32.7 ng/mL) in males and 20.8 ng/mL (IQR 14.4–28.2 ng/mL) in females. Overall, the median 25(OH)D concentration decreased with age in both males and females. Males had a 0.2–2.4 ng/mL higher median 25(OH)D concentration than females in different age groups. Vitamin D deficiency (25(OH)D < 15 ng/mL for the individuals under 14 years old; < 20 ng/mL for the individuals over 14 years old) was found in 21.3% of males and 43.6% of females. Significant seasonal variation of serum 25(OH)D concentrations was repeatedly observed in 3 years, with median concentration higher in summer (25.3 ng/mL (IQR 19.3–31.9 ng/mL)) and lower in winter (18.5 ng/mL (IQR 12.3–26.6 ng/mL)). Vitamin D status varied by province. The median 25(OH)D concentration was the highest in Hainan (31.0 ng/mL (IQR 24.9–39.2 ng/mL)) and the lowest in Qinghai (14.4 ng/mL (IQR 9.6–20.0 ng/mL)). 25(OH)D2 was detected in 12.2% of the results, and no significant seasonal variation was observed. Conclusion: In China, vitamin D deficiency is prevalent in the population participating in clinical vitamin D measurement. Age and sex differences in vitamin D levels were observed in our study. Seasonal variation and provincial differences are important aspects of serum vitamin D status. 25(OH)D2 cannot be ignored entirely in clinical measurement practice in China. [ABSTRACT FROM AUTHOR]

Background. Traditional Chinese medicine Smilax is the rhizome of liliaceous plant Smilax china L., which is used to treat pelvic inflammatory disease and anxieties. Purpose. To investigate the mechanism of anti-inflammatory activity of the extract from Smilax china L. (ES). Methods. The components of ES were identified by UPLC-QTOF-MS/MS. The anti-inflammatory activities were evaluated in xylene-induced ear oedema and egg white-induced plantar swelling test. Cell viability was examined by CCK-8 assay. The inflammatory mediators, proinflammatory cytokines, and MAPK and NF-κB signals in LPS-stimulated THP-1 cells were determined using ELISA, real-time PCR, and Western blot, respectively. Results. 20 compounds of ES were confirmed by comparing with the reference substance. ES displayed more prominent anti-inflammatory activity than the positive control "Jin Gang Teng" capsule in the in vivo acute inflammatory model. ES suppressed the expression of PGE2 and 6-Keot-PGF1α, and the ratio of IC50 (COX-1)/IC50 (COX-2) of ES was 3.15, which indicated that ES could selectively inhibit COX-2. ES dose-dependently (12.5, 25, and 50 mg/L) decreased the production and mRNA levels of proinflammatory cytokines IL-1β, IL-6, and TNF-α. Furthermore, ES significantly decreased LPS-induced phosphorylation of p38, JNK, ERK1/2, and p65, inhibiting the expression of IKKα and the degradation of IκBα. Conclusion. The results suggested that ES could selectively inhibit the activity of COX-2, and the anti-inflammatory effect of ES was associated with the inhibition of IL-1β, IL-6, and TNF-α via negative regulation of MAPK and NF-κB signaling pathways in LPS-induced THP-1 cells. [ABSTRACT FROM AUTHOR]

Objective: We aimed to describe the 25-hydroxyvitamin D (25(OH)D) status of southern Chinese individuals by a high-accuracy liquid chromatography tandem mass spectrometry (LC-MS/MS) method which can trace to reference measurement procedure. Materials and methods: From January 2018 to June 2019, a total of 4775 southern Chinese individuals were evaluated in our study. The serum levels of parathyroid hormone (PTH) were detected simultaneously in 162 cases. 25(OH)D was determined by LC-MS/MS, and PTH was detected using routine automated analysers. The distribution of the concentration, prevalence and seasonal variability of 25(OH)D in males and females of different age groups were studied. Results: The mean 25(OH)D concentration in our study was 32.57 ng/mL (4.20–101.40 ng/mL). The global 25(OH)D concentration in males was higher than that in females of different age group. The prevalence of vitamin D deficiency (< 20 ng/mL) in females (16.65%) was higher than that in males (6.83%). The prevalence of vitamin D deficiency (< 20 ng/mL) was most common in winter (22.98% of all women and 15.49% of all men). 25(OH)D concentrations were higher in those from whom blood samples were collected in summer and autumn than in winter and spring. 25(OH)D2 was detected in 672 serum samples (14.07%). In addition, there was a negative correlation between the concentrations of 25(OH)D and serum PTH (r = − 0.149, P < 0.05). Conclusion: Our study demonstrated that the average serum 25(OH)D concentration in southern Chinese individuals was higher than that in other Chinese cohorts by a high-accuracy LC-MS/MS method. The global 25(OH)D concentration in males was higher than that in females of different ages, and the prevalence of vitamin D deficiency in females was higher than that in males. Seasonal change was an important aspect of 25(OH)D concentration in young and middle-aged people but became less relevant for that in older subjects. 25(OH)D2 detection was of minor practical significance in our study. In addition, we also found that there was a negative correlation between the serum levels of 25(OH)D and PTH in southern Chinese individuals. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via the original article. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first design of DNA-peptide probes targeting lncRNA with high specificity and efficient detection. • A novel method for the quantitative analysis of lncRNAs is proposed, utilizing LC-MS/MS and DNA-peptide probes. • The first application of mass spectrometry in conjunction with DNA-peptide probe technology for liver cancer diagnosis. Liver cancer, a prominent contributor to cancer-related deaths, necessitates timely identification for successful intervention. In recent years, long non-coding RNAs (lncRNAs) have gained attention as potential biomarkers for liver cancer, and accurate quantification of lncRNA is essential for early diagnosis of liver cancer. However, existing methods for lncRNA detection rely on amplification and labeling techniques, resulting in semi-quantitative or qualitative outcomes. DNA-peptide technology offers a promising alternative. It has successfully translated nucleic acid quantification into peptide quantification, particularly in the context of miRNA analysis. However, the intricate structure of long-chain lncRNAs presents a challenge not encountered with miRNAs, making the design and acquisition of specific DNA-peptide probes for direct quantification more difficult. In this study, a strategy for lncRNA quantification was developed using a DNA-peptide probe coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based quasi-targeted proteomics. The inherent structural complexity of long-chain lncRNAs was overcome by designing DNA-peptide probes based on their unique sequence segments, enabling direct quantification without the need for amplification. Highly upregulated in liver cancer (HULC) was identified as a target lncRNA through bioinformatics analysis using GEO2R online software. Subsequently, the target lncRNA (i.e., HULC), which had been biotinylated and bound to streptavidin agarose beforehand, was hybridized with the probe. Following trypsin digestion, the reporter peptide was released and quantified using LC-MS/MS. Finally, this method was applied to analyze HULC levels in liver cancer cell lines and serum samples, enabling quantitative assessment and early diagnosis. The results demonstrated that liver cancer diagnostics could be enhanced through the integration of mass spectrometry and DNA-peptide probe technology for lncRNA quantification. [ABSTRACT FROM AUTHOR]

Isotope-labeled proteins are expected to be used as internal standard proteins in the field of protein quantification by isotope dilution mass spectrometry (ID/MS). To achieve the absolute quantification of Cystatin C (Cys C) based on ID/MS, we aims to obtain 15N isotope-labeled recombinant Cys C (15N-Cys C) protein. Firstly, the Cys C gene was optimized based on the preferred codons of Escherichia coli , and inserted into the pET-28a(+) expression plasmid. Then, the plasmid was transformed into TOP10 and BL21 strains, and 15N-Cys C was expressed in M9 medium using 15N as the only nitrogen source. 15N-Cys C was detected by SDS-PAGE, protein immunoblotting and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The characteristic peptides obtained from 15N-Cys C were analyzed by a Q Exactive Plus MS system. Results showed that 53.06% of the codons were optimized. The codon adaptation index of the Cys C genes increased from 0.31 to 0.95, and the GC content was adjusted from 64.85% to 54.88%. The purity of 15N-Cys C was higher than 95%. MALDI-TOF MS analysis showed that the m / z of 15N-Cys C had changed from 13 449 to 14 850. The characteristic peptides showed that 619.79 m/z (M+2H)2+ was the parent ion of 15N-Cys C and that the secondary ions of 15N-labeled peptides from y+5 to y+9 were 616.27 m/z, 716.33 m/z, 788.39 m/z, 936.43 m/z, and 1052.46 m/z, respectively. In conclusion, we successfully expressed, purified and identified of 15N-Cys C protein in Escheichia coli intended for absolute quantification using ID/MS. • The 15N isotope labeled Cys C was successfully expressed and purified, and the purity was more than 95% for the first time. • The codon and GC content of gene were optimized to improve the express yield. • The purified 15N labeled Cys C was confirmed by SDS-PAGE and MALDI-TOF MS. [ABSTRACT FROM AUTHOR]