Time distribution of positive nucleic acid detection in imported cases infected with SARS-CoV-2 in China / 中华流行病学杂志

Objective: To analyze the time distribution of the first positive nucleic acid detection in imported cases infected with SARS-CoV-2 reported nationwide in China and provide references for further improvement of the prevention and control of COVID-19 in international travelers. Methods: The data of imported cases infected with SARS-CoV-2 reported by provinces from 24 July 2020 and 23 July 2021 were collected for the analysis on the time distribution of the first positive nucleic acid detection after entering China. Results: A total of 7 199 imported cases infected with SARS-CoV-2 were reported in 28 provinces during 24 July 2020 to 23 July 2021. The median interval (Q1, Q3) from the entry to the first positive nucleic acid detection of SARS-CoV-2 was 1 (0, 5) day. The imported cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry accounted for 95.15% (6 850/7 199) and 4.85% (349/7 199) respectively. Among these cases, 3.65% (263/7 199), 0.88% (63/7 199) and 0.32% (23/7 199) had the first positive nucleic acid detections within 15-21 days, 22-28 days and 28 days later after the entry respectively. The proportion of asymptomatic infections were 47.24% (3 236/6 850) and 63.61% (222/349) among the cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry respectively. A total of 39.54% (138/349) of cases infected with SARS-CoV-2 with the first positive nucleic acid detections 14 days later after the entry had inter-provincial travel after the discharge of entry point isolation. Conclusions: About 5% of the imported cases infected with SARS-CoV-2 were first positive 14 days later after the entry. In order to effectively reduce the risk of domestic COVID-19 secondary outbreaks caused by imported cases, it is suggested to add a nucleic acid test on 8th -13th day after the entry.

Virtual screening of components of safflower against myocardial ischemia based on molecular docking technology / 中国中药杂志

The screening of active components of traditional Chinese medicine has always been the focus and difficulty in modern research of Chinese medicine preparations. With the continuous development of life science, omics and computer technology, the virtual screening technology for active components of traditional Chinese medicine has gradually come into people's vision. Molecular docking technology is an important method for screening active components of traditional Chinese medicine. It not only has a short cycle and strong operability, but also avoids the disadvantage of poor stability in pharmacological experiments. Safflower extract can effectively alleviate the symptoms of myocardial ischemia, but its active components are not clear. In this study, with use of the molecular docking technology, the active components in safflower against myocardial ischemic were virtually screened based on the screening method of active components. Forty-six chemical components and 5 target proteins which showed high correlation with myocardial ischemia were obtained from the existing database and related literature reports. With the molecules of three commercially available drugs diltiazem, trimetazidine and verapamil as positive control molecules, the compomnents were docked with 5 target proteins. Active components were screened according to docking scores and interactions between molecules and targets, and then the active ingredients can be inferred. Fourteen chemical components were screened to have the most potential anti-myocardial ischemic activity, and all of them were flavonoids. Therefore, it can be inferred that the flavonoid components are the most potential anti-myocardial ischemic components in safflower. The screening of active anti-myocardial ischemia components in safflower was completed in this study, laying the foundation for subsequent researches.

Effect of GnRHa controlled ovarian hyperstimulation on mouse embryo implantation and its mechanism / 生理学报

The purpose of the present study was to investigate the effects and underlying mechanism of gonadotropin-releasing hormone agonist (GnRHa) controlled ovarian hyperstimulation (COH) on embryo implantation in mice. Forty female Kunming mice aged 9 weeks were randomly divided into two groups (control and COH groups). The COH group received intraperitoneal (i.p.) injections of aminocyclin acetate (GnRHa), human menopausal gonadotropin (HMG) and human chorionic gonadotropin (hCG), while the control group was given equal amount of physiological saline by i.p. injection. One male mouse and two female mice were put into the same cage at 16:00 on the hCG injection day, and on the fourth day of pregnancy, 10 mice from each group were killed. The levels of serum estradiol (E) and progesterone (P) were measured by radioimmunoassay; HE staining was used to observe the morphology of ovarian and endometrial tissues. The protein expression levels of endometrial leukemia inhibitory factor (LIF), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), heparin-binding epidermal growth factor-like growth factor (HB-EGF) and glycodelin A were detected by Western blot and immunohistochemistry. Ten mice from each group were sacrificed on the eighth day of pregnancy, and the status of the uterus and the average number of blastocysts were observed. The results showed that, compared with control group, the serum E level in COH group was significantly decreased (P < 0.05), while the P level was increased significantly (P < 0.05); the ovarian follicles at different developmental stages were rare, corpus lutea (CL) were visible and multiple, the endometrium was thinned, and the number of endometrial glands was reduced (P < 0.05); the contents of LIF, p-STAT3, HB-EGF and glycodelin A in the endometrium were decreased significantly (P < 0.05) on the fourth day of pregnancy; mouse blastocysts developed slowly and were decreased in number on the eighth day of pregnancy (P < 0.05). The above results suggest that GnRHa COH can affect embryo implantation in mice. The mechanism may be related to the imbalance of gonadal hormone, the changes in the structure of the endometrium and the expressions of LIF, p-STAT3, HB-EGF and glycodelin A in the implantation stage, which may lead to the decrease of endometrial receptivity and the abnormal dialogue between the embryo and the uterus.

Analysis on plantar force parameters of gait under different simulated gravities / 医用生物力学

Objective To investigate the plantar force characteristics during human walking and running under different gravity environment. Methods Seven healthy male volunteers walked and ran in vertical position on a weight-loss suspension treadmill under simulated Mars gravity (1/3 G) and lunar gravity (1/6 G), and traditional earth gravity (1 G) respectively at three different velocities (3, 7 and 10 km/h). During the exercise, parameters such as stance phase, plantar force, and gait balance in gait cycle were analyzed by using the F-scan insole pressure distribution measurement system. Results At the same velocity during a gait cycle, the contact phase was significantly shorter with the decrease of gravity, but the swing phase was significantly longer (P0.05). The peak and average plantar force, force integrity were significantly reduced with the decrease of gravity. Under normal gravity, the increase of velocity could lead to an obvious increase in peak and average plantar force and an obvious decrease in force integrity. While under simulated lunar and Mars gravity, no significant changes were found in plantar force (P>0.05). Under the three gravities, the ratio of vertical impact was quite different in between (P<0.05), but no significant difference was found in the phase symmetry index. Conclusions As compared to normal gravity environment, parameters benefiting for skeleton and muscle function such as plantar force and contact phase were found to be much smaller under low gravity environment, indicating the necessity of considering these factors when designing countermeasures or exercise prescriptions for space flight so as to sustain the astronaut’s normal function of skeleton and muscle.

Effect of simulated microgravity and its associated mechanism on pulmonary circulation in rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the effect of Simulated Microgravity and its Associated Mechanism on Pulmonary Circulation in Rats).</p><p><b>METHODS</b>Rat tail-suspension model was used to simulate the physiological effects of microgravity and changes in pulmonary blood vessel morphology, pulmonary arterial and venous blood pressure, pulmonary vascular resistance, pulmonary vasomotoricity, as well as the regulation of pulmonary circulation by cytokines produced and released by the lung of rats were measured.</p><p><b>RESULTS</b>The walls of pulmonary blood vessels of rats were thickened, and the pulmonary artery was reconstructed with increased pulmonary vascular resistance. The pulmonary blood vessels of rats became more prone to dilation as contractions increased. Rat epithelial Adrenomedulin gene transcription and protein expression were upregulated. The level of basic fibroblast growth Factor of rat was also elevated.</p><p><b>CONCLUSION</b>Findings from the present study on rats revealed that the microgravity can affect pulmonary blood vessel structure, pulmonary arterial pressure, and pulmonary blood vessel self-regulation and cytokine production.</p>

Relative bioavalability of hydrochloride eperisone granule in healthy volunteers / 中国临床药理学与治疗学

Aim The relative bioavalability of hydrochloride eperisone granule in 10 healthy volunteers was studied. Methods The time-plasma concentrations of hydrochloride eperisone granule, as test drug, and myonal, as reference drug, were determined by GC-MS, with tolperisone senuing as internal standard.The pharmacokinetic parameters of both reference and test drug were calculated and analyzed with two-one side test and confidential interval test. Results The results showed that the AUC0-8, AUC0-∞, Cmax, Tpeak, t1/2(?) and t1/2(?) were (17.9?1.3)ng?h?ml-1 and(18.6?1.6)ng?h?ml-1, (19.1?1.2)ng?h?ml-1 and (20.2?1.6)ng?h?ml-1, (5.2?0.5)ng?ml-1 and (5.4?0.5) ng?ml-1, (1.05?0.18)h and (1.08?0.23)h, (0.78? 0.13)h and ( 0.82?0.14)h,( 1.8?0.3)h and (1.8?0.3)h, respectively. The relative bioavalability of test drug was (105? 5)%. Conclusion It can be concluded that the test and reference are bioequivalented between individuals, preparations and periods.