Objective We aimed to explore the mechanism by which Bushen Yangjing Soup improves elderly infertility based on oocyte mitochondrion.Methods C57BL/6J mice were used,including 15 young females(6-8 weeks old),45 elderly females(10 months old),and ten young males(6-8 weeks old).The female 6-8-week-old young mice were assigned to the young group,and the female 10-month-old elderly mice were randomly divided into the model group,the dehydroepiandrosterone(DHEA)group,and the Bushen Yangjing Soup group.Mice in the DHEA and Bushen Yangjing Soup groups were given DHEA[11.26 mg/(kg·d)]and Bushen Yangjing Soup[11.41 g/(kg·d)].Mice in the other groups were given normal saline.After 45 days,oocytes were collected,the number of oocytes and the proportion of mature oocytes were recorded,and in vitro fertilization(IVF)was carried out,followed by calculation of the successful fertilization rate.Real-time PCR was used to determine the copy number of mitochondrial DNA in oocytes,mito-tracker green was used to observe the distribution of mitochondria,and the mitochondrial membrane potential(MMP)of oocytes was determined using the JC-1 kit.The mRNA and protein levels of mitofusin 2(Mfn2)in oocytes were determined by real-time PCR and Western blotting,respectively.Results Compared with the young group,the number of oocytes,the proportion of mature oocytes,and the IVF rate were significantly reduced(P＜0.01),the copy number of mitochondrial DNA in oocytes was decreased,the rate of abnormal mitochondrial distribution was increased,the MMP was decreased(P＜0.01),and the mRNA and protein levels of Mfn2 were decreased(P＜0.01)in the elderly model mice.Compared with the elderly model group,the number of oocytes,the proportion of mature oocytes,and the IVF rate were significantly increased(P＜0.05),the copy number of mitochondrial DNA in oocytes was increased(P＜0.05),the rate of abnormal mitochondrial distribution was decreased,the MMP was increased(P＜0.05),and the mRNA and protein levels of Mfn2 were increased(P＜0.01)in the Bushen Yangjing Soup group.Compared with the DHEA group,the number of oocytes,the proportion of mature oocytes,and the IVF rate were increased,the copy number of mitochondrial DNA in oocytes was increased,the rate of abnormal mitochondrial distribution was decreased,the MMP was increased,the mRNA and protein levels of Mfn2 were increased in the Bushen Yangjing Soup group,and there was a significant difference in the number of oocytes and the expression of Mfn2 protein(P＜0.05).Conclusion Bushen Yangjing Soup may improve the quantity,distribution,and function of oocyte mitochondria by increasing the mRNA and protein levels of Mfn2,thereby improving oocyte quality.This is one of the possible mechanisms for clinical application of Bushen Yangjing Soup to improve ovarian function and treat elderly infertility.

Clostridioides difficile is a key pathogen of antibiotic related diarrhea and hospital associated infection, causing several outbreaks in Europe and North Americans and resulting in severe disease burden. However, the standardized diagnostic principle and detection specifications in C. difficile infection (CDI) survey are limited in China, and the infection rate and disease burden of CDI in China are unclear. Therefore, National Institute for Communicable Disease Control and Prevention,National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, together with another 11 institutions, draft the group standard entitled "Diagnosis of Clostridium difficile infection (T/CPMA 008-2020)" of Chinese Preventive Medicine Association. Based on the principle of "legality, scientificity, advancement, and feasibility", this standard clarifies risk factors, diagnosis principles, diagnoses and differential diagnoses in order to improve the accuracy of CDI diagnosis in clinical practice, guide the surveillance for CDI, and understand the infection rate and disease burden of CDI in China .

Objective:To assess the risk of COVID-19 foreign imports cases to China.Methods:We collected epidemic data (cumulative daily confirmed cases in each country, cumulative confirmed imported cases), demographic data (population density, population) and information on potential source groups of tourists (the daily estimated number of overseas Chinese, overseas Chinese students, overseas workers, foreign students coming to China and flight passengers) and the global health security index (GHS) to assess and predict risk of imported cases for recent (February 1 st to April 25 th) and future (after April 26 th). Results:Strong positive correlation was found among variables including the number of imported cases, cumulative confirmed cases, attack rate, number of overseas Chinese, number of overseas Chinese students, number of foreign students coming to China, number of flight passengers and GHS. In the recent risk analysis, imported cases of Russian were the highest, followed by United Kingdom, United States, France and Spain. In the future risk prediction, 44 countries including United States and Singapore are evaluated as potential high-risk countries in the future through the attack rate index of each country and the estimated average number of daily passengers.Conclusion:The risk assessment of COVID-19 imported cases can be used to identify high-risk areas in recent and future, and might be helpful to strengthen the prevention and control of the epidemic and ultimately overcome the epidemic.

Objective:To infer the start time of the resurgent COVID-19 epidemic in Xinfadi wholesale market in Beijing in June 2020 and evaluate the effect of comprehensive prevention and control measures in this epidemic.Methods:SEIR dynamics model was used to fit daily onset infections to search the start date of this resurgent COVID-19 epidemic in Beijing. The number of cumulative infections from June 12 to July 1 in Beijing were fitted considering different levels of control strength.Results:The current reemerged COVID-19 epidemic in Beijing probably started between May 22 and May 28 (cumulative probability: 95 %), with the highest probability on May 25 (23 %). The R0 of the current reemerged COVID-19 epidemic was 4.22 (95 %CI: 2.88-7.02). Dynamic model fitting suggested that by June 11, the cumulative number of COVID-19 cases would reached 99 (95 %CI: 77-121), which was in line with the actual situation, and without control, by July 1, the cumulative number of COVID-19 cases would reach 65 090 (95 %CI: 39 068-105 037). Since June 12, comprehensive prevention and control measures have been implemented in Beijing, as of July 1, compared with uncontrolled situation, the number of infections had been reduced by 99 %, similar to the fitting result of a 95 % reduction of the transmission rate. The sensitivity analysis showed consistent results. Conclusions:For the emergent outbreak of COVID-19, the dynamics model can be used to infer the start time of the transmission and help tracing the source of epidemic. The comprehensive prevention and control measures taken in Beijing have quickly blocked over 95 % of the transmission routes and reduced 99 % of the infections, containing the sudden epidemic timely and effectively, which have value in guiding the prevention and control of the epidemic in the future.

Objective To explore the clinical features and risk factors of poor prognosis in neonatal necrotizing enterocolitis(NEC).Methods A retrospective study was carried out in the infants with NEC admitted to 6 cooperative hospitals in Guangdong Province between January 2005 and December 2014.The clinical features and risk factors of poor prognosis in preterm and full-term infants diagnosed NEC,early onset and late onset NEC were analyzed.Results A total of 449 cases who met the criteria were admitted during the study time.The mortality was 23.6％ (106/449 cases),of which the preterm group was 24.6％ (58/238 cases) while the full-term group was 22.7％ (48/211 cases),the early onset group was 22.1％ (45/204 cases) while the late onset group was 24.3％ (57/235 cases).The median number of NEC onset in preterm group was 11 d after birth while the number of the full-term group was 6 d.Full-term infants who diagnosed NEC were more likely to manifest themselves as abdominal distension (52.1％ vs.42.0％,x2 =4.597,P =0.032),vomiting(36.5％ vs.17.2％,x2 =21.428,P =0.000) and bloody stool(30.3％ vs.21.4％,x2 =4.653,P =0.031);but in the onset of NEC,preterm infants more likely to have feeding intolerance (21.0％ vs.12.8％,x2=5.309,P =0.021).The early onset group of full-term NEC was much common in twins or multiplets(9.4％ vs.1.1％,x2 =6.226,P =0.013),which rate of surgical therapy was much higher (41.0％ vs.27.0％,P =0.036) and the breast-feeding rate before NEC was lower than the late onset group(14.5％ vs.32.6％,x2 =9.500,P =0.002),the differences were statistically significant.The gestational age and birth weight were bigger in the early onset group of preterm NEC[(33.8 ±2.5) weeks vs.(32.2 ±2.8) weeks,t =4.261,P =0.000;(2.1 ±0.5) kg vs.(1.7 ± 0.5) kg,t =4.735,P =0.000)],but length of stay was shorter than the late onset group (18.0 d vs.26.5 d,P =0.000).Logistic regression analysis showed that the risk factors of poor prognosis of full-term NEC were shock,peritonitis and sepsis;while risk factors of poor prognosis of preterm NEC were small for gestational age infant,pulmonary hemorrhage,shock,intestinal perforation and sepsis;the risk factors of poor prognosis of the early onset group of full-term NEC was shock;while those of the late onset group were shock and peritonitis;the risk factors of poor prognosis in the early onset group of preterm NEC were shock and sepsis,while those in the late onset group were pulmonary hemorrhage,shock,intestinal perforation and sepsis.Conclusions Compared to the preterm NEC,the onset time of full-term NEC was earlier and the clinical manifestations were more typical.Early identification and management of shock,peritonitis,intestinal perforation,sepsis and pulmonary hemorrhage can reduce the risk of poor prognosis of neonate NEC.

Objective: To establish a standard operation procedure (SOP) for ribosome genotyping (ribotyping) on Clostridioides (C.) difficile, supplement and verify ribotyping typing library, so as to improve the comparability of data between different laboratories and to develop surveillance network of C. difficil in China. Methods: Molecular typing of 54 reference strains from the United States and Europe of C. difficile were performed by using the SOP referencing correspondence from abroad and from our laboratory with a BioNumerics 7.6 software to estimate the reference library of types of C. difficile. Identification of 374 clinical and animal isolates of C. difficile from 13 cities in China between 2010 and 2018, to supplement the library information. Kappa test was used to evaluate the consistency. Results: Results of capillary electrophoresis of reference strains appeared clear and stable, which guaranteed the clustering results being fast and accurate. Results from the supplementary typing showed that there were 84 types of isolates, of which 25 RT types were consistent with reference strains from abroad, while 58 RT types were different from referenced types. In the 40 referenced types, 15 RT types were not found in this study. In the consistency evaluation, the Kappa value was 0.891 and (P<0.01), showing the two Molecular typing as consistent and with close resemblance. Conclusions The result of capillary electrophoresis by applying SOP for ribotyping on C. difficile base on QIAxcel capillary electrophoresis system, appeared clear and stable. The standardized library seemed more easily used for comparability and data sharing between the laboratories.

Objective To investigate the residents' acceptance and the influencing factors of the hierarchical medical system in Xuzhou, and to suggest on effective system implementation. Methods Xuzhou residents free of cognitive impairment and over 18 years old were sampled for questionnaire survey in July-August 2016, to study their acceptance of their basics and acceptance of the system. 1 550 questionnaires were distributed, and 1 473 valid ones were recovered. The count data were expressed as constituent ratio, and χ2test was used for single-factor analysis, with binary logistic regression analysis for multi-factor analysis. Results 71. 0% of the residents embraced this system. Their acceptance varies significantly with their age, place of residence, education, annual average monthly income, self-rated health status, physical examination experience, conditions of chronic diseases, medical visit experience at primary healthcare institutions, and their awareness of the system (P<0.05). Conclusions The acceptance of the system by Xuzhou residents needs to be elevated, by means of greater promotional efforts, capacity building for primary institutions, so as to fully leverage the system to serve the residents.

Objective To establish an easily reproducible rabbit model of acute pulmonary embolism (APE) with right ventricular dysfunction (RVD).Methods Two gelfoam strips (5 rnm×5 mm× 10 mm) were squeezed and were introduced into the pulmonary arteries of each healthy rabbit (n=12).Pulmonary and systemic hemodynamic function were recorded.All rabbits underwent CT pulmonary angiography (CTPA) and pathological examination after the introduction of APE.Results All gelfoam strips located in the bilateral lower lobe arteries.Compared with baseline mean pulmonary artery pressure (mPAP) ([9.75±1.75] mmHg),mPAP increased to (20.58 ± 5.86) mmHg immediately after embolism (P ＜ 0.001),and then decreased to (18.78 ±4.80) mmHg 1 h after embolism (P＜0.001).Right ventricle/left ventricle diameter ratio (RV/LV) increased from baseline (0.67±0.09) to (1.90±0.28) 45 min after embolism (P＜0.001).Conclusion An easily reproducible rabbit model of APE with RVD are established and may be suitable for study of APE pathophysiology.

Objective To study the effect of SKF96365 and NiCl2 on cyclopiazonic acid (CPA) induced intracellular calcium cation concentration ([Ca2+ ]i ) change in rat distal pulmonary arterial smooth muscle cells (PASMC) .Methods The rat distal PASMC were isolated and cultured .The effects of CPA ,SKF96365 and NiCl2 on [Ca2+ ]i in PASMC were tested by fluorescence microscope and InCyte [Ca2+ ]i measurement system .Results PASMC were incubated with Ca2+‐free Krebs solution containing 5μmol/L nifedipine ,10 μmol/L CPA caused a small transient increase in [Ca2+ ]i ;after restoration of extracellular Ca2+ to 2 .5 mmol/L ,10 μmol/L CPA caused marked increases in [Ca2+ ]i in PASMC incubated with Krebs solution containing 5 μmol/L nife‐dipine .Both 50 μmol/L SKF96365 and 500 μmol/L NiCl2 distinctly attenuated the increases in [Ca2+ ]i caused by 10 μmol/L CPA in PASMC .However ,neither 50 μmol/L SKF96365 nor 500 μmol/L NiCl2 affected the increases in [Ca2+ ]i caused by 60 mmol/L KCl in PASMC .Conclusion CPA induced increases in [Ca2+ ]i may related to Ca2+ release from sarcoplasmic reticulum and the in‐flux of Ca2+ through store‐operated Ca2+ channels (SOCC) in rat distal PASMC .Both SKF96365 and NiCl2 could selectively block SOCC and attenuated the influx of Ca2+ through SOCC in PASMC .

Objective To observe late effect of 60Co radiation accident on eye lens in the victims.Methods Medical observations of eye lens were performed on ten victims accidentally exposed to 60Co sources in four radiation accidents that have occurred from 1986 to 2000 in Henan Province.Pathological changes of the eye lenses were examined by using slit lamp microscopy after mydriasis with compound tropicamide.Results Of these ten victims, Liang in a radiation accident in Kaifeng (in 1986), Mei in Xinxiang (in 1999) and Xu in Xuchang (in 2000) all had typical radiation-induced cataract 2, 3 and 6 years after irradiation, respectively.Follow-up observation of the lens showed the punctate and/or granular opacities present in the eye posterior subcapsular of Yan in Kaifeng accident, Jie in Zhengzhou (1987), and Tian, Yong and Yi in Xinxiang accident, featuring the early changes of radiation-induced cataract, but the posterior subcapsular opacities were not observed in Wang and Min in Xinxiang accident.Conclusions Focus should be on the eye lens as the target organ of radiation exposure in long-term follow-up of victims accidentally exposed to radiation source.Severity of the lens opacity induced by ionizing radiation is closely associated with radiation doses.