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BACKGROUND Iron is the most abundant element on earth with variable valences. It is widely distributed in various minerals, rocks, fluids and organisms, and is involved in diagenesis, mineralization, hydrothermal activities and life activities. The study of iron isotope composition provides important information for geochemistry, astrochemistry and biochemistry. The accurate measurement of Fe isotopes is an important basis for the development of related research. OBJECTIVES To summarize the research progress of Fe isotope measurement technology. METHODS The current chemical separation and purification methods and main instrumental analysis techniques commonly used for iron isotopes, were compared and analyzed in this review, and the mechanism of different types of fractionations during mass spectrometry were discussed. These advances included:(1) Improvement of anion resin during determination of iron isotope by solution method; (2) Mass spectrometry development from traditional thermal ionization mass spectrometry to multi-collector inductively coupled plasma mass spectrometry; (3) Development of laser in situ analytical technology. On this basis, the steps and calibration methods that would cause iron isotope fractionation during the analysis were summarized, and the advantages and disadvantages of different analytical methods were reviewed. RESULTS The analysis process of solution method was long and complicated, but the precision was high (0.03‰, 2SD) and the method was stable. In situ iron isotope analysis method developed from nanosecond laser denudation to femtosecond laser denudation, with shorter pulse duration, higher pulse peak intensity (up to 1012W), and focusing intensity exceeding 1020W/cm2. In situ iron isotope analysis method was fast and had high spatial resolution, which can be used to discuss the geochemical process from the microscopic perspective. However, the presence of matrix effects limited the widespread use of iron isotopes. CONCLUSIONS Shortening solution analysis process and developing a series of matrix-matched standard samples are the research direction of iron isotope analysis.

BACKGROUND The conventional method for the measurement of sulfur isotopes in sulfate includes mainly barite conversion coupled with dual-inlet SO2 methods. These methods are facile and reliable. However, the large amounts of samples, the length of time needed, the laborious experimental work, and complicated preprocessing are impractical for the development direction of micro-analysis. OBJECTIVES To develop a method for determination of sulfur isotope compositions in gypsum directly through continuous flow elemental analyzer-isotope mass spectrometry (EA-IRMS). METHODS Two different preparation methods were used. (1) Direct measurement of sulfur isotopes was carried out by mixing calcium sulfate powder with V2O5 in a tin cup using EA-IRMS. (2) Calcium sulfate was fully dissolved in deionized water. The precipitation reagent BaCl2 was added to the liquid in which the calcium sulfate sample was dissolved. After the precipitated barium sulfate was filtered out, it was washed 2 to 3 times with deionized water. Samples were dried and mixed with V2O5 in a sealed tin cup and then determined by mass spectrometry. RESULTS The δ34S values of 13 gypsum samples ranged from -20‰ to -30‰, and the results from replicate measurements were compared for these two methods, yielding the absolute difference in δ values were 0.0-0.2 permil, indicating that the sulfur isotope ratios of the same sample were basically identical. CONCLUSIONS Compared with the conventional analysis method, the application of 'no pretreatment' to analyze the sulfur isotopes of gypsum was conducted successfully. Adding V2O5 to samples directly, during the process of instantaneous combustion, the oxygen in calcium sulfate are substituted by the external oxygen in V2O5 and oxygen gas, and the obtained oxygen of SO2 gas is uniform. Therefore, sulfur isotope ratios of SO2 can completely represent those of the calcium sulfate, making it unnecessary for oxygen isotope correction. The direct online analysis of sulfur isotopes in calcium sulfate samples using EA-IRMS is verified to be feasible.

Mitogen-activated protein kinase 15 (MAPK15) has been reported to be associated with several cancers. This study aimed to explore for the first time on the relationship between MAPK15 expression and cancer progression/drug responsiveness in ovarian carcinoma. To this end, MAPK15 expression level was examined by immunohistochemistry (IHC) staining of an ovarian tissue array (10 normal and 70 malignant samples). Drug sensitivity of ovarian cancer cell lines (including OVCAR3 and SKOV3) was measured by MTS assay. The modulation of MAPK15 expression in OVCAR3 and SKOV3 was verified by immunoblot and real-time PCR analyses. The prognostic value of MAPK15 in ovarian cancer patients was assessed using the Kaplan-Meier Plotter database and Gene Expression Omnibus (GEO) datasets. The IHC results showed that MAPK15 expression was negatively associated with tumor grade, TNM stage, tumor size, and regional lymph node metastasis of ovarian carcinoma. Importantly, overexpressing MAPK15 increased cisplatin toxicity in ovarian carcinoma cells and online database analysis indicated that patients with high MAPK15 expression had favorable prognosis with/without chemotherapy. Taken together, our results indicate that a decreased MAPK15 expression is associated with advanced-stage ovarian cancer and unfavorable survival outcomes. MAPK15 may be a new biomarker for ovarian cancer, and the encouraging therapeutic strategy would be found by combining the regulation of MAPK15 expression. [ABSTRACT FROM AUTHOR]

The cytochrome P450s (CYP450s) include key oxidative enzymes involved in the metabolism of various carcinogens and anticancer drugs. Bioinformatic studies have demonstrated the association of CYP3A43 with liver cancer and ovarian cancer. However, the biological function of CYP3A43 in tumor progression remains unclear. To further reveal the role of CYP3A43 in tumor progression, we first analyzed the data from the UALCAN database and found that CYP3A43 was negatively correlated to the cancer staging and lymph node metastasis of lung adenocarcinoma (LUAD). We established stable CYP3A43-knockdown LUAD H1299 cell line and found that its knockdown enhanced cell proliferation, colony formation, and migration in vitro, and promoted the growth of tumor xenograft in vivo. Interestingly, when CYP3A43 was ectopically-expressed in the LUAD cell lines, decreased cell proliferation and ERK1/2 phosphorylation level were observed. Lastly, we also identified CYP3A43 co-expressed genes in LUAD from LinkedOmics database followed by GO and KEGG analyses. In conclusion, our results indicate the unprecedented role of CYP3A43 in the suppression of LUAD and provide new possibilities for targeted therapy of this life-threatening disease. [ABSTRACT FROM AUTHOR]

Objective: To study the effect of total flavonoids of Rhizoma Drynariae on the expression of NMDAR1, GluR2 and CAMK II protein in model mice of kidney deficiency induced by exogenous glucocorticoid hydrocortisone and its mechanism. Methods: Kunming (KM) mice were randomly divided into the blank group, the hydrocortisone model group, the anti-brain failure capsule group, the Drynaria total flavonoids group, the Drynaria total flavonoids+ER blocker group, with 15 animals in each group. Except for the blank group, all groups were injected intramuscularly with hydrocortisone (25 mg·kg-1·d-1) to create models. The water maze experiment, new object recognition experiment and platform jump experiment were used to conduct behavioral investigations. HE staining was used to observe the pathological changes of mouse hippocampus, and Western blotting detected the expressions of NMDR1, GluR2 and CAMK II proteins in the hippocampus of mice in each group. Results: The experimental results showed that compared with the model group, the learning and memory ability of the mice in the Drynaria fortunei total flavonoids group was significantly improved, and the difference was statistically significant (P <0.01), the expression of NMDR1 and GluR2 proteins in the hippocampus of the mice was significantly increased (P<0.01), and the level of CAMK II protein significantly decreased (P<0.01). Conclusion: The total flavonoids of Rhizoma Drynariae may enhance the expression of NMDAR1 and GluR2 protein in the brain of hydrocortisone model mice through ER, reduce the expression of CAMK II protein, and alleviate the damage to the brain tissue of the model mice and play a neuroprotective effect. [ABSTRACT FROM AUTHOR]