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Background Since the implementation of the "universal two-child" policy, multiparous women has become the main labor and delivery population. Problems such as advanced maternal age, chronic comorbidities, obstetric complications and pregnancy after cesarean section have become increasingly prominent, bringing new challenges to obstetricians. Objective To analyze the current status of cesarean section in multiparous women under the new childbearing policy based on the revised Robson classification system, in order to provide data support for rational control of cesarean section rate, improvement of obstetric care. Methods A total of 19 170 women who delivered by cesarean section in the Tenth Affiliated Hospital, Southern Medical University from 2017 to 2020 were included and divided into the primipara group (n=5 630) and multiparous group (n=13 540). Maternal information including age, gravity, parity, previous deliveries, fetal position, pregnancy comorbidities and complications, maternal and fetal outcomes, was collected through the electronic medical records. The general information and maternal and neonatal outcomes of the two groups were compared. The revised Robson classification system was used to classify the parturients according to their obstetric characteristics (parity, fetal position, number of fetuses and gestational weeks of delivery). The distribution of parturients in the revised Robson classification system and the change of the proportion of parturients in each group with year were compared. Results The proportion of pregnancy after cesarean section was as high as 81.4% (11 026/13 540). The age, gravity, parity, proportion of age ≥35 years and gestational diabetes mellitus of the multiparous group were higher than the primipara group (P0.05) . Conclusion Advanced age and pregnancy after cesarean section are prominent features of multiparous women. Although the proportion of R3 class decreased by year, it is still the main population of cesarean section. In order to reduce cesarean section rate, it is necessary to effectively control the cesarean section of primipara women, and actively promote the vaginal trial of labor for women in R3 class. Meanwhile, the proportion of R2 and R8 in the multiparous women, which put forward new requirements for clinical practice of obstetrics.

Objective To investigate the effect and underlying mechanism of roxadustat on apoptosis and senescence of renal tubular epithelial cell line HK-2 induced by heat stress. Methods After HK-2 cells were treated with different concentrations of roxadustat (10, 20, 30, 40 and 50 μmol/L) for 24 h, CCK-8 assay was used to determine the optimal intervention concentration of roxadustat. HK-2 cells were divided into 4 groups (n=3): control group, roxadustat group (30 μmol/L, 24 h), heat-stress group (43 ℃, 2 h), and heat-stress+roxadustat group (30 μmol/L roxadustat treatmnet for 24 h followed by heat-stress 2 h). Cell viability was detected by CCK-8 assay. Expression of hypoxia-inducible factor-1α (HIF-1α), Cleaved Caspase-3, p16 and p21 at protein level was detected by Western blotting. Immunofluorescence assay was employed to observe the distribution of HIF-1α. β-galactosidase staining kit was utilized to detect SA-β-Gal activity. TUNEL staining was used to measure cell apoptosis. Results The highest cell viability was observed in the cells after 30 μmol/L roxadustat treatment. Heat stress resulted in a significant decrease in cell viability (P < 0.05), elevated protein levels of HIF-1α, Cleaved Caspase-3, p16 and p21(P < 0.05), enhanced SA-β-Gal activity (P < 0.05) and increased percentage of TUNEL-positive cells (P < 0.05) when compared with the cells in the control group. In comparison with the heat-stress group, the heat-stress+roxadustat group showed significant decrease in the protein levels of Cleaved Caspase-3, p16 and p21 (P < 0.05), reduced activity of SA-β-Gal [(65.44±5.00)% vs (77.15±2.61)%, P < 0.05] and decreased percentage of TUNEL-positive cells [(16.73±2.20)% vs (46.40±13.87)%, P < 0.05], but increase in cell viability [(86.33±4.51)% vs (66.33±8.50)%, P < 0.05] as well as HIF-1α protein expression (P < 0.05). Furthermore, immunofluorescence assay showed that HIF-1α was mainly distributed in the nucleus and perinucleus. Conclusion Roxadustat attenuates heat stress-induced apoptosis and senescence of renal tubular epithelial cells by upregulating HIF-1α.

A gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring (SIM) method for the precise quantitative and qualitative analysis of 58 volatile components in grape fruits of different varieties using stable isotope labeled internal standard was developed based on the understanding of the mass spectrometric cleavage behavior of special volatile components. The difference in the volatile composition of the tested varieties was explored. After crushing and homogenization, grape samples were extracted by solid phase microextraction (SPME) and analyzed by GC-MS-SIM. The results indicated that this method had good linear relationships within the investigated concentration range with a correlation coefficient (R) greater than 0.995 0 for all analytes expect for isopropanol (equal to 0.967 1). The limits of detection (LODs) for most target compounds were lower than 1.56 μg/kg. The spiked recoveries of only a few volatile components were very low, while those of most volatile components ranged from 60.64% to 129.63% with relative standard deviations (RSDs) less than 19.56%. This method was suitable for qualitative and quantitative analysis of volatile components in grape and other fruits as well as vegetables, with high sensitivity and accuracy. Furthermore, the characteristic volatile components of 12 grape varieties were identified by analyzing the differences in their volatile composition.

Objective: To establish a HPLC-MS /MS method for simultaneous determination of five pesticides residues in - cluding tebuconazole,metalaxyl-M, thiophanate-methyl, oxytetracycline and abamectin in Anoectochilus roxburghii. Methods; The samples were extracted by acetonitrile solution and purified by QuEChERS method. Separation was performed on Agilent Eclipse Plus Ci8 column (50 mmx2.1 mm, 1.8m ) with the mobile phase consisting of 0. 1% formic acid (A ) and acetonitrile (B ) by gradient elution (0-1.0 min,90% A ;1.0-3.0 min,90% -70% A ;3.0-5.0 min,70% -30% A ;5.0-8.0 min,30% -10% A ; 8.0-14.0 min, 10% A ;14.0-15.0 min, 10%-90% A ;15.0-17.0 min, 90% A ). Detection was performed on a triple quadrupole tandem mass spectrometry with electrospray ionization source operating in positive ion mode under multiple reaction monitoring (M RM ) mode.Results : The calibration curves of five pesticides showed good linearity coefficients ( r>0.99 ).The average re¬coveries ranged from 72.7% to 94.9% (n=6),and the relative standard derivations (RSDs ) were within 1.8% -10.3% ( n-6 ). The detection limits of tebuconazole,metalaxyl-M,thiophanate-methyl,oxytetracycline and abamectin were 0.6,0.2,0.3,0.2, 5.0g /kg,and the quantitation limits of 5 pesticides were 2.0,0.5,1.0,0.6 and 10.0 ^g /kg respectively.Conclusion; The established method was proved to be sensitive, simple and reliable, and could be applied for the determination of these five pesticides in Anoectochilus roxburghii and quality control in the planting process. [ABSTRACT FROM AUTHOR]