Taking the mechanism of glucose catabolism disorder in depression as an example to explore the research ideas and strategies of stable isotope tracer metabolomics / 药学学报

Stable isotope tracer metabolomics tracks and analyzes the whole metabolic process of the body through the tracer atoms, which belongs to the frontier technology in the field of biomedicine. This technology is of great significance and value for explaining the pathogenesis of diseases, finding biomarkers of diseases and drug action targets. Taking the mechanism of glucose catabolism disorder in depression as an example, this paper systematically expounds the stable isotope tracer metabolomics technology and its application. The research idea of stable isotope tracer metabolomics based on unmarked metabolomics was put forward, and the research strategy of biological significance interpretation from four dimensions of metabolite isotope abundance, key metabolic enzymes, metabolic flow direction and metabolite flow was given, which broke through the bottleneck of stable isotope tracer metabolomics research technology based on overall animal experiment, and provided scientific basis for the promotion and application of this technology.

Discrimination of cultivation modes of Dendrobium nobile based on content of mineral elements and ratios of nitrogen stable isotopes / 中国中药杂志

This study explored the feasibility of mineral element content and ratios of nitrogen isotopes to discriminate the cultivation mode of Dendrobium nobile in order to provide theoretical support for the discrimination of the cultivation mode of D. nobile. The content of 11 mineral elements(N, K, Ca, P, Mg, Na, Fe, Cu, Zn, Mn, and B) and nitrogen isotope ratios in D. nobile and its substrate samples in three cultivation methods(greenhouse cultivation, tree-attached cultivation, and stone-attached cultivation) were determined. According to the analysis of variance, principal component analysis, and stepwise discriminant analysis, the samples of different cultivation types were classified. The results showed that the nitrogen isotope ratios and the content of elements except for Zn were significantly different among different cultivation types of D. nobile(P<0.05). The results of correlation analysis showed that the nitrogen isotope ratios, mineral element content, and effective component content in D. nobile were correlated with the nitrogen isotope ratio and mineral element content in the corresponding substrate samples to varying degrees. Principal component analysis can preliminarily classify the samples of D. nobile, but some samples overlapped. Through stepwise discriminant analysis, six indicators, including δ~(15)N, K, Cu, P, Na, and Ca, were screened out, which could be used to establish the discriminant model of D. nobile cultivation methods, and the overall correct discrimination rates after back-substitution test, cross-check, and external validation were all 100%. Therefore, nitrogen isotope ratios and mineral element fingerprints combined with multivariate statistical analysis could effectively discriminate the cultivation types of D. nobile. The results of this study provide a new method for the identification of the cultivation type and production area of D. nobile and an experimental basis for the quality evaluation and quality control of D. nobile.

Research progress of metabolic flux analysis technology in glucose metabolism pathway research / 药学学报

With the wide application of stable isotope tracer metabolomics technology, its comprehensive analysis and in-depth mining of data are particularly important, and metabolic flux analysis is one of the main technical means, especially in the study of glucose metabolism. Metabolic flux analysis technology combines isotope tracing with mathematical models to deduce and calculate the metabolic flux between metabolites. The metabolic flux provides more information for research and reflects a dynamic metabolic process more clearly and specifically. This paper reviews the basic process, precautions, and application examples of metabolic flux analysis in glucose metabolism research, and provides a reference for the application of metabolic flux analysis based on stable isotope tracer metabolomics in glucose metabolism research.

Application and prospect of stable isotope technology in tracing geographical origin of Chinese herbal medicines / 中国中药杂志

As a unique medical resource in China, Chinese herbal medicine plays a key role in the prevention and treatment of human diseases. With the gradual expansion of applications, the quality of Chinese herbal medicine has become the focus of attention. The quality of Chinese herbal medicines depends largely on their source authenticity. Tracing the origin of Chinese herbal medicines plays an important role in ensuring their quality and efficacy and reducing the mixing and adulteration of Chinese herbal medicines from different regions. Stable isotope technology, as a key technology for origin tracing of agricultural products and food, has been used in the research of Chinese herbal medicines from multiple sources and origins in recent years. This new technological means contributes to standardizing the origin of Chinese herbal medicines and controlling their quality from the source. Apart from introducing the basic principles of stable isotope technology and the characteristics of common stable isotopes, this study reviewed the application status of light and heavy stable isotopes in the origin tracing of Chinese herbal medicines and their correlation with ecological factors, and forecasted the application prospect of this technology in the authentication of Chinese herbal medicines, aiming to provide reference for the geographical origin tracing of Chinese herbal medicines and promote the sustainable development of traditional Chinese medicine.

Application of stable isotope-resolved metabolomics in glucose catabolism / 药学学报

With the rapid development of high sensitivity detection techniques such as nuclear magnetic resonance and mass spectrometry, stable isotope-resolved metabolomics has been widely used in elucidating the regulatory mechanism of metabolic pathways and metabolic flow analysis, and some breakthroughs have been made. In this paper the application of stable isotope-resolved metabolomics in glucose catabolic regulation, metabolic flow analysis and functional interpretation of key metabolic pathways is reviewed, providing references for the wider use and application of this technology.

Origin traceability of main root of spring Panax notoginseng based on stable isotope fingerprint / 中国中药杂志

This paper established the identification technology of the main root origin of three-year-old spring Panax notoginseng aiming at providing theoretical basis for the protection and traceability of geographical indication products of P. notoginseng. Forty-four samples of three-year-old spring P. notoginseng from Guangxi Baise, Yunnan Wenshan, Yunnan new cultivating regions. The stable isotopic ratios of carbon, nitrogen, hydrogen and oxygen were determined by elemental analysis and stable isotope mass spectrometer. Combined with Duncan multiple comparative analysis, fisher discriminant analysis and sequential discriminant analysis, a origin discriminant model for the main root of three-year-old spring P. notoginseng was established for 3 production areas of P. notoginseng. The geographical climate and environment of three production areas of P. notoginseng are obviously different. From Guangxi Baise-Yunnan Wenshan-Yunnan new cultivating regions, the longitude, average annual temperature and annual precipitation gradually decrease, and the elevation and latitude are increasing. The results of multiple comparative analysis showed that there were significant or very signi-ficant differences in the δ~(13)C,δ~(15)N,δ~2H,δ~(18)O of the main roots of P. notoginseng in three regions. The results of fisher's discriminant analysis and sequential discriminant analysis showed that the correct discriminant rates of the main roots of P. notoginseng for three regions were 80.05%,76.47% and 90.91%, respectively, based on four stable isotope ratios, with an average of 84.09%. Using stable isotope fingerprint and chemometrics method, we can distinguish the origin of the main raw materials and products of P. notoginseng.

Evaluation of Erythrocyte Iron Incorporation in Beijing Prepubertal Children Using a Single Stable Isotope Tracer Method / 生物医学与环境科学（英文）

Objective@#To analyze the rate of erythrocyte iron incorporation and provided guidance for the iron nutrition for prepubertal children.@*Methods@#Fifty-seven prepubertal children of Beijing were involved in this study and each subject was orally administered 3 mg of Fe twice daily to obtain a total of 30 mg Fe after a 5-d period. The stable isotope ratios in RBCs were determined in 14th day, 28th day, 60th day, and 90th day. The erythrocyte incorporation rate in children was calculated using the stable isotope ratios, blood volume and body iron mass.@*Results@#The percentage of erythrocyte Fe incorporation increased starting 14 th day, reached a peak at 60 d (boys: 19.67% ± 0.56%, girls: 21.33% ± 0.59%) and then decreased. The erythrocyte incorporation rates of Fe obtained for girls in 60th day was significantly higher than those obtained for boys ( < 0.0001).@*Conclusions@#The oral administration of Fe to children can be used to obtain erythrocyte iron incorporation within 90 d. Prepubertal girls should begin to increase the intake of iron and further studies should pay more attention to the iron status in prepubertal children.

Geographical origin discriminant of Panax japonicus based on stable isotope ratios analysis / 中草药

Objective: The isotopic ratios of light elements (C/N/H/O) in Panax japonicus from six producing areas were determined with isotope ratio mass spectrometry.Methods: Three methods, including linear discrimination (LD), gaussian kernel support vector machine (SVM), and the back-propagation learning algorithm of pattern recognition based on neural network toolbox (BPN) were employed to establish a model for P. japonicus geographical origin discrimination. Results: The results showed that stable isotope carbon (δ 13C) had obvious regional characteristics, which will be used to effectively distinguish the origin of P. japonicus. The methods of LD and BPN could classify the geographical origin of P. japonicus from six producing areas, both of which showed that the accuracy rates were 100% using training dataset. Conclusion: Therefore, the stable isotope technique combined with LD and BPN method can effectively trace the origin of P. japonicus.

Protein quality & amino acid requirements in relation to needs in India

The relevance of protein and its constituent amino acids (AAs) in the structure and function of the human body is well known. Accumulating evidence has conferred specific functional and regulatory roles for individual AAs, adding relevance to their requirements across different age groups. The methods for measuring AA requirements have progressed from the classical nitrogen balance to the current stable isotope-based AA balance methods. Requirements of most of the indispensable AA (IAA) have been estimated in healthy Indian population by the best available balance method and has shown to be higher than earlier 1985 WHO/FAO/UNU (World Health Organization/Food and Agriculture Organization/United Nations University) recommendations. In addition, potential changes in the requirement, through adaptation to chronic undernutrition or to infection, have also been evaluated. In 2007, the WHO/FAO/UNU released a recommendation that increased the daily IAA requirement, based on primary evidence from Indian balance studies. This meant that to ensure that the new IAA requirements were met, individual foods or mixed diets needed to be assessed for their protein quality, or their ability to deliver the required amount of IAA. The recent FAO report on protein quality evaluation recommends the use of a new chemical AA score, the digestible IAA score (DIAAS), to replace the earlier protein digestibility corrected AA score. The DIAAS requires the determination of individual AA digestibility at the ileal level. A minimally invasive dual stable isotope tracer-based approach has been developed in India and has been used to determine digestibility of various foods in Indian adults and children. The increase in IAA requirements and subsequent protein quality requirements have implications for national regulatory frameworks, growth and development, and in turn, for economic and agricultural policy.

Inferior Assimilation of Algae-based Diets by Sea Cucumber Holothuria scabra under Laboratory Condition Expressed by Stable Isotope Mixing Model

Aim: To investigate the dietary preferences of sea cucumber Holothuria scabra fed with algal food sources like Sargassum, Fucus, Spirulina, Ulva in combination with marine pellet under laboratory condition. Carbon stable isotope technique (δ13C) was used to better understand the assimilation of different dietary food sources. Study Design: A microcosm approach was undertaken where 24 experimental aquaria were set up, each having juvenile H. scabra. These aquaria were segregated into four different dietary treatments with six replicates per treatment. (SGP treatment= Sargassum + marine pellet, FCP treatment= Fucus + marine pellet, SPP treatment= Spirulina + marine pellet, ULP treatment= Ulva + marine pellet). Place and Duration of Study: Marine Experimental Ecology Unit (MAREE), Leibniz Centre for Tropical Marine Research, Bremen, Germany, between January and October 2017. Methodology: We included 24 sea cucumber juveniles for conducting the feeding trial. CN contents, C/N ratio and carbon stable isotopes were measured in food sources as well as in H. scabra body wall. The growth of H. scabra was also monitored. Stable isotope mixing model was used to calculate the exact food preference under laboratory condition. Results: The results of carbon stable isotopes (δ13C) of sea cucumber body wall exhibited depleted values that are significantly different (ANOVA, P˂0.05) from all the dietary treatments (SGP, FCP, SPP, ULP) thereby suggesting inferior assimilation of food ingredients. The poor performance of selected food sources (algae and marine pellet) towards the growth of sea cucumber was clearly reflected in the data (ANOVA, P>0.05). Conclusion: Therefore, it is assumed that some additional food source co-existed within the microcosm and could have contributed to their food uptake, probably sediment microbes that require further clarification.

Geographical origin discriminant of Polygoni Multiflori Radix based on stable isotope ratios and elemental analysis / 中国中药杂志

The seventy samples of Polygoni Multiflori Radix were collected from three producing areas: Bozhou, Anhui province, Jingmen, Hubei province and Xichang, Sichuan province. Three stable isotope ratios and contents of 44 elements in the Polygoni Multiflori Radix samples were determined by EA-IR-MS and HR-ICP-MS. Three data mining methods，including partial least square discriminant analysis (PLS-DA), fisher linear discriminant analysis (FLDA) and decision tree CHAID were employed to establish a model for geographical origin discrimination．The study results showed that the stable isotope ratios expressed significant difference followed with the different producing areas, and will be used to discern the samples from different producing areas, effectively. Combined with the data of elemental analysis, the accuracy rates of model can be further improved. All the three methods showed the accuracy rates of external sample were over 90% using training dataset. These results confirmed that stable isotope ratios and multi-elemental analysis combined with chemometric method was effectiv in geographical tracing of Polygoni Multiflori Radix．The analysis method has great potential and prospect in geographical origin discriminant of Chinese medicinal materials, and provids a new study method to identify origin information of Chinese medicinal materials.

Geographical origin discriminant of Dendrobium officinale based on stable isotope ratios / 中国中药杂志

The isotopic ratios of strontium isotope (Sr) and light elements (C/H/O/N) in Dendrobium officinale from different producing areas (Shaoguan, Guangdong; Yulin, Guangxi; Shibing, Guizhou; Wenshan, Yunnan and Zhejiang province) were determined with thermal ionization mass spectrometry (TI-MS) and isotope ratio mass spectrometry (IRMS)．The differences of the stable isotope ratios in D. officinale were obtained by the variance analysis and the correlation analysis, and pattern recognition techniques with principal component analysis (PCA) was used to classify the geographical origins of D. officinale from different producing areas．The isotopic ratios of strontium isotope can be used to identified D. officinale in Zhejiang province, and the isotopic ratios of light elements showed the difference followed with the different producing areas. For δD and δ¹⁸ O in samples, maybe influenced by the environment effect. A positive correlation was found between δD and δ ¹⁸O.The principal component analysis was used to discern the samples of D. officinale from different producing areas based on detection technology of stable isotope ratios.These results revealed that it was possible and feasible to classify the geographical origin of D. officinale by the method of determination of isotopes,and provided a new method to identificate origin information of Chinese medicinal materials.

Pharmacokinetics of levornidazole disodium phosphate in monkey / 药学学报

This study was carried out to investigate the pharmacokinetics/bioequivalence of levornidazole disodium phosphate by using stable isotope labeled drug, evaluated the pharmacokinetic profile and confirmed the prodrug characteristics of levornidazole disodium phosphate in monkey. Levornidazole (Drug A) and stable isotope 15N labeled levornidazole disodium phosphate (Drug B) were mixed with equal mole amount (experiment I); stable isotope 15N labeled levornidazole disodium phosphate (Drug B) and levornidazole disodium phosphate (Drug C) were mixed with equal mole amount, respectively. After giving the mixed drugs to the monkey, the concentration of 15N-levornidazole disodium phosphate, levornidazole disodium phosphate, 15N-levornidazole and levornidazole in plasma samples of pre-dosing and 24 h after administration were analyzed by a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method. Pharmacokinetic calculations were performed through non-compartmental analysis using WinNonlin software. Two-sided 90% confidence intervals (CI) were used to evaluate the bioequivalence of two drugs. The results showed that levornidazole disodium phosphate was metabolized to levornidazole rapidly after administration, the body exposure were increased with the dosage. The method of bioequivalence used in this study was different from the traditional two periods, crossover design. By using the method of this study, the effects of administration period, intra-individual variability, and sequence of administration on bioequivalence were avoided. The results of this study had successfully supported the pharmacokinetic and bioequivalence study of this drug in human using the same approach.

A Fast Analytical Approach for Determination of 16 Kinds of Mycotoxins in Vegetable Oils Using Stable Isotope Dilution and Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry / 分析化学

A fast, simple and cost-effective UPLC-MS / MS method was established for determination of 16 kinds of mycotoxins in vegetable oils with stable isotope dilution technique. Samples were extracted by acetonitrile-water-acetic acid 84: 15: 1(V/ V) and then diluted using water without any further clean-up steps. The mycotoxins were fully separated on a pentafluorophenyl column. Matrix effects were efficiently compensated by the [ 13 C]-labelled internal standards. The mean recoveries at three different concentration levels ranged from 74. 2％ to 105. 6％ , with RSD varied from 0. 3％ to 13. 9％ . Finally, the method was applied to analyze several kinds of vegetable oil samples. The method was simple, rapid, high sensitive and suitable for the determination of mycotoxins in vegetable oils.

Design and synthesis of deuterium-labeled vorapaxar / 中国药科大学学报

Vorapaxar,a novel antagonist of the protease-activated receptor 1 (PAR-1 ),can inhibit the clotting process. Deuterium-labeled vorapaxar was required for the analysis of clinical sample as an internal stand-ard. Starting for unlabeled vorapaxar,four-step reactions including hydrolysis,condensation,transesterification and hydrogen-deuterium exchange were carried out to synthesize [D8]vorapaxar effectively for the first time. All intermediates and final products were confirmed by NMR and high resolution mass spectrometry (HRMS).Impor-tantly,the prepared [D8]vorapaxar could meet the requirements of sample analysis as the internal standard.

Applications progress of stable isotopic tracer technique in metabolic regulation of endogenous substances / 中草药

With the rapid development of high-sensitivity detection methods, stable isotope tracing technique has received increasing attention. Stable isotope tracing technique can accurately track the activity of labeled compounds in the body through the tracer atoms and determine their specific metabolic pathways based on the distribution of isotopic peaks of the intermediate metabolites. By calculating the flux, the metabolic pathways are analyzed to provide a basis for the study of disease mechanism and drug metabolism. In recent years, the technique has a wide application in the field of biomedicine. This paper summarizes the applications of stable isotopic tracer technique in the metabolic regulation of endogenous substances such as carbohydrate metabolism, lipid metabolism, amino acid metabolism, hormone metabolism, nucleic acid metabolism, and so on.

Arginine and Citrulline for the Treatment of MELAS Syndrome

Abstract Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a maternally inherited mitochondrial disease with a broad spectrum of manifestations. In addition to impaired energy production, nitric oxide (NO) deficiency occurs in MELAS syndrome and leads to impaired blood perfusion in microvasculature that can contribute to several complications including stroke-like episodes, myopathy, and lactic acidosis. The supplementation of NO precursors, L-arginine and L-citrulline, increases NO production and hence can potentially have therapeutic utility in MELAS syndrome. L-citrulline raises NO production to a greater extent than L-arginine; therefore, L-citrulline may have a better therapeutic effect. The clinical effect of L-citrulline has not yet been studied and clinical studies on L-arginine, which are limited, only evaluated the stroke-like episodes' aspects of the disease. Controlled studies are still needed to assess the clinical effects of L-arginine and L-citrulline on different aspects of MELAS syndrome.

Zinc Absorption from Representative Diet in a Chinese Elderly Population Using Stable Isotope Technique / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To determine the dietary zinc absorption in a Chinese elderly population and provide the basic data for the setting of zinc (Zn) recommended nutrient intakes (RNI) for Chinese elderly people.</p><p><b>METHODS</b>A total of 24 elderly people were recruited for this study and were administered oral doses of 3 mg 67Zn and 1.2 mg dysprosium on the fourth day. The primary macronutrients, energy, and phytic acid in the representative diet were examined based on the Chinese National Standard Methods. Fecal samples were collected during the experimental period and analyzed for zinc content, 67Zn isotope ratio, and dysprosium content.</p><p><b>RESULTS</b>The mean (± SD) zinc intake from the representative Chinese diet was 10.6 ± 1.5 mg/d. The phytic acid-to-zinc molar ratio in the diet was 6.4. The absorption rate of 67Zn was 27.9% ± 9.2%. The RNI of zinc, which were calculated by the absorption rate in elderly men and women, were 10.4 and 9.2 mg/d, respectively.</p><p><b>CONCLUSION</b>This study got the dietary Zn absorption in a Chinese elderly population. We found that Zn absorption was higher in elderly men than in elderly women. The current RNI in elderly female is lower than our finding, which indicates that more attention is needed regarding elderly females' zinc status and health.</p>

Application of stable isotope dilution liquid chromatography-mass spectrometry in medical research / 国际药学研究杂志

Stable isotope dilution mass spectrometry(ID-MS)is a quantitative method for determining the content of unla?beled compounds with stable isotope labeled compounds as internal standard. Stable isotope dilution liquid chromatography-mass spec?trometry(ID-LC-MS)has the advantages of high sensitivity,no quantitative separation of the analytes,and effective elimination of the biological matrices. The method has been widely used in quantitative analysis of biomarkers,drugs and their metabolites. In this pa?per,the mechanism and characteristics of ID-LC-MS are briefly introduced,and its medical applications are summarized.

Application of stable isotope dilution liquid chromatography-mass spectrometry in medical research / 国际药学研究杂志

Stable isotope dilution mass spectrometry(ID-MS)is a quantitative method for determining the content of unlabeled compounds with stable isotope labeled compounds as internal standard. Stable isotope dilution liquid chromatography-mass spectrometry(ID-LC-MS)has the advantages of high sensitivity, no quantitative separation of the analytes, and effective elimination of the biological matrices. The method has been widely used in quantitative analysis of biomarkers, drugs and their metabolites. In this paper, the mechanism and characteristics of ID-LC-MS are briefly introduced, and its medical applications are summarized.