OBJECTIVE: To develop and validate a user-friendly risk score for older mitral regurgitation (MR) patients, referred to as the Elder-MR score. METHODS: The China Senile Valvular Heart Disease (China-DVD) Cohort Study functioned as the development cohort, while the China Valvular Heart Disease (China-VHD) Study was employed for external validation. We included patients aged 60 years and above receiving medical treatment for moderate or severe MR (2274 patients in the development cohort and 1929 patients in the validation cohort). Candidate predictors were chosen using Cox's proportional hazards model and stepwise selection with Akaike's information criterion. RESULTS: Eight predictors were identified: age ≥ 75 years, body mass index < 20 kg/m², NYHA class III/IV, secondary MR, anemia, estimated glomerular filtration rate < 60 mL/min per 1.73 m², albumin < 35 g/L, and left ventricular ejection fraction < 60%. The model displayed satisfactory performance in predicting one-year mortality in both the development cohort (C-statistic = 0.73, 95% CI: 0.69-0.77, Brier score = 0.06) and the validation cohort (C-statistic = 0.73, 95% CI: 0.68-0.78, Brier score = 0.06). The Elder-MR score ranges from 0 to 15 points. At a one-year follow-up, each point increase in the Elder-MR score represents a 1.27-fold risk of death (HR = 1.27, 95% CI: 1.21-1.34, P < 0.001) in the development cohort and a 1.24-fold risk of death (HR = 1.24, 95% CI: 1.17-1.30, P < 0.001) in the validation cohort. Compared to EuroSCORE II, the Elder-MR score demonstrated superior predictive accuracy for one-year mortality in the validation cohort (C-statistic = 0.71 vs. 0.70, net reclassification improvement = 0.320, P < 0.01; integrated discrimination improvement = 0.029, P < 0.01). CONCLUSIONS The Elder-MR score may serve as an effective risk stratification tool to assist clinical decision-making in older MR patients.

Gut microbiome sequencing studies have great potential to translate microbial analysis outcomes into human health research. Sequencing strategies of 16S amplicon and whole-metagenome shotgun (WMS) are two main methods in microbiome research with respective advantages. However, how sample heterogeneity, sequencers and library preparation protocols affect the sequencing reproducibility of gut microbiome needs further investigation. This study aims to provide a reference for the selection of sequencing technologies by comparing differences in microbial composition from different sampling sites. The results of three widely adopted sequencers showed that the technical repetition correlation (r= 0. 94) was high in WMS method, while the biological repetition correlation (r = 0. 69) was low. Bray-Curtis distance identified that dissimilarity from biological replicates was larger than that of technical replicates (P<0. 001). In addition, dissimilarity and specific taxonomic profiles were observed between 16S and WMS datasets. Our results imply that homogenization is a necessary step before sample DNA extraction. The sequencers contributed less to taxonomic variation than the library preparation protocols. We developed an empirical Bayes approach that " borrowed information" in calculations and analyzed batch effect parameters using standardized data and prior distributions of (non-) parameters, which may improve population comparability between 16S and WMS and provide a basis for further application to fusion analysis of published 16S and microbial datasets.

In the past 37 years, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) has undergone various major transmission routes in China, with the world most complex co-circulating HIV-1 subtypes, even the prevalence is still low. In response to the first epidemic outbreak of HIV in injecting drug users and the second one by illegal commercial blood collection, China issued the Anti-Drug Law and launched the Blood Donation Act and nationwide nucleic acid testing, which has avoided 98,232 to 211,200 estimated infections and almost ended the blood product-related infection. China has been providing free antiretroviral therapy (ART) since 2003, which covered >80% of the identified patients and achieved a viral suppression rate of 91%. To bend the curve of increasing the disease burden of HIV and finally end the epidemic, China should consider constraining HIV spread through sexual transmission, narrowing the gaps in identifying HIV cases, and the long-term effectiveness and safety of ART in the future.
Acquired Immunodeficiency Syndrome/prevention & control* ; China/epidemiology* ; Disease Outbreaks ; HIV Infections/prevention & control* ; Humans ; Prevalence

The outbreak of coronavirus disease 2019 (COVID-19) was declared a global public health emergency on 31 January 2020. Emergency medicine procedures in Emergency Department should be optimized to cope with the current COVID-19 pandemic by providing subspecialty services, reducing the spread of nosocomial infections, and promoting its capabilities to handle emerging diseases. Thus, the Chinese Society of Emergency Medicine and Wuhan Society of Emergency Medicine drafted this consensus together to address concerns of medical staffs who work in Emergency Department. Based on in-depth review of COVID-19 diagnosis and treatment plans, literatures, as well as management approval, this consensus proposes recommendations for improving the rationalization and efficiency of emergency processes, reducing the risk of nosocomial infections, preventing hospital viral transmission, and ensuring patient safety.

OBJECTIVETo investigate the presence of leukemia stem cells (LSC) in acute myeloid leukemia (AML) and find out the relative position of leukemia cells in the figures of flow cytometry, and to analyze the relationship between minimal residual diseases (MRD) and the level of LSC, so as to explore the correlation of LSC changes with the curative effect and the prognosis during chemical therapy.

METHODSA total of 85 samples were collected from 50 AML (except M3) patients, including 50 samples from the newly diagnosed patients, 7 samples of AML patients with non-remission and 28 samples of AML patients with complete remission. All samples were used for detection of LSC from immune phenotype of CD34/CD38/CD123 by flow cytometry. The detection of immune phenotypic of leukemia cells was performed in the newly diagnosed patients. The detection of leukemia- associated immune phenotypes (LAIP) was implemented in the non-newly diagnosed patients.

RESULTSThe LSC was identified in the CD34/ CD38/ CD123 in AML and consistent with the relative position of the leukemia cell in flow cytometry figures. Statistical analysis showed significant difference in LSC content between the newly diagnosed AML group and the post-chemotherapy complete remission group(P<0.01),but did not between the newly diagnosed AML group and the post-chemotherapy non-remission group(P>0.05).There was significant positive correlation between the LSC content and MRD level in 28 AML patients with complete remission (r=0.680,P<0.01).

CONCLUSIONLSC exist in AML and the relative position are consistent with the leukemia cells in flow cytometry figures, the size characteristics and weak expression of CD45 are also similar to leukemia cells. The proportion of LSC decreases after chemotherapy. Detecting and tracking the LSC changes in bone marrow and combination with detecting minimal resident disease(MRD) may contribute to evaluate the theraputic efficacy and prognosis of leukemia patients.

OBJECTIVETo explore the optimal implantation strategy of tissue-engineered liver (TEL) constructed based on decellularized spleen matrix (DSM) in rats.

METHODSDSM was prepared by freeze-thawing and perfusion with sodium dodecyl sulfate (SDS) of the spleen of healthy SD rats. Primary rat hepatocytes isolated using modified Seglen 2-step perfusion method were implanted into the DSM to construct the TEL. The advantages and disadvantages were evaluated of 4 transplant strategies of the TEL, namely ectopic vascular anastomosis, liver cross-section suture transplantation, intrahepatic insertion and mesenteric transplantation.

RESULTSThe planting rate of hepatocytes in the DSM was (74.5∓7.7)%. HE staining and scanning electron microscopy showed satisfactory cell status, and immunofluorescence staining confirmed the normal expression of ALB and G6Pc in the cells. For TEL implantation, ectopic vascular anastomosis was difficult and resulted in a mortality rate of 33.3% perioperatively and massive thrombus formation in the matrix within 6 h. Hepatic cross-section suture failed to rapidly establish sufficient blood supply, and no viable graft was observed 3 days after the operation. With intrahepatic insertion method, the hepatocytes in the DSM could survive as long as 14 days. Mesenteric transplantation resulted in a hepatocyte survival rate of (38.3+7.1)% at 14 days after implantation.

CONCLUSIONTEL constructed based on DSM can perform liver-specific functions with a good cytological bioactivity. Mesenteric transplantation of the TEL, which is simple, safe and effective, is currently the optimal transplantation strategy.

BACKGROUND: There are various methods to observe and detect early angiogenesis in the process of entochondrostosis, but each holds certain deficiencies.OBJECTIVE: To explore the possibility of tetracycline and alizarin complexone as an indirect marker ofangiogenesis in the process of entochondrostosis.METHODS: New Zealand white rabbit models of bilateral radial bone defects were prepared, followed by β-tricalcium phosphate implantation, and then given the injection of tetracycline and alizarin complexone at 1 and 15 days,respectively. Samples were collected at 28 days, some of which were observed using fluorescence/light microscope after ink perfusion and hard tissue slicing, and the others were decalcified and observed using immunohistochemistry. The uniformity between lumen structures labeled with bone affinity fluorescein and vascular structures marked by immunohistochemistry and ink perfusion was compared.RESULTS AND CONCLUSION: The lumen structure labeled with bone affinity fluorescein was confirmed to be a CD34 positive vascular structure. Under the fluorescence microscope, the bone affinity fluorescein labeled vascular morphology was consistent with ink perfusion-labeled, and black ink lines could be observed in the lumen structures labeled with bone affinity fluorescein after ink perfusion. In addition, the color of the lumen labeled with fluorescein was more gorgeous,three-dimensional structure more vivid, and the vascular evolution process distinguished more easily by different fluorescein colors, exhibiting unique advantages. Therefore, it is available to detect the early angiogenesis in the process of entochondrostosis.

Objective To obtain different biomechanical conditions of the tibia section with different osteotomy thickness under different activity states,so as to provide theoretical basis for total knee arthroplasty (TKA) and patient activities after operation.Methods The three-dimensional models of lower limb were reconstructed and the proximal tibia was resect by 0 mm,5 mm,7 mm,9 mm,respectively,based on the principle of bone resection in TKA.The tibia models after osteotomy were assigned with the material properties,and the stress and strain of the tibia cross-section were then analyzed under the following activity states:standing,walking,running and climbing upstairs.Results The stress and displacement of the tibia cross-section increased with the increase of osteotomy thickness under the same activity state.The maximum stress and displacement of tibia cross-section with the same osteotomy thickness showed an increasing trend when the strength of activity increased.Conclusions For TKA in clinic,the stress and strain on tibia cross-section become larger with the thicker tibia osteotomy and the stronger postoperative activity.Excessive osteotomy in TKA and activity too intensively after TKA should be avoided,so as to reduce stress and strain of the tibia plateau and promote long-term life of the prosthesis.

BACKGROUND: Revascularization is a challenge for the tissue-engineered bone carrying cells after implanted into human body. Previous studies have found that tanshinol can improve the functions of endothelial progenitor cells and exert vascular protective effects.OBJECTIVE: To prepare the β-calcium phosphate (β-TCP) scaffold with tanshinol coating, and to observe its cytocompatibility.METHODS: The β-TCP scaffolds coated with 10-7, 10-6 and 10-5 mol of tanshinol were constructed by negative pressure absorption method. The distribution of tanshinol coating on the scaffold was observed using scanning electron microscopy,and the inner ingredients were analyzed by infrared spectrum. Human endothelial progenitor cells (hEPCs) were cultured in the extracts of β-TCP and β-TCP scaffolds with 10-7, 10-6, 10-5 mol of tanshinol coatings, respectively. The cell proliferation was detected at 2, 4, 6, 8 and 10 days of culture; the levels of nitric oxide and vascular endothelial growth factor in the supernatants were detected at 1, 7 and 14 days of culture; the lumen formation on the matrigel was observed after 14-day culture. hEPCs were respectively seeded onto the β-TCP and β-TCP scaffolds with different dosages of tanshinol coating,and then the cell growth was observed under scanning electron microscope at 7 days.RESULTS AND CONCLUSION: The tanshinol coating evenly distributed on the inner surface of the pores, and its crystalline structure became dense with dosage increasing. Infrared spectrum analysis revealed no changes in the characteristic absorption peak of tanshinol and TCP in the scaffold. The β-TCP scaffolds with tanshinol coating could promote the proliferation of hEPCs, especially the scaffolds with 10-6 and 10-5 mol tanshinol coating. Compared with the β-TCP scaffold, the scaffolds with 10-6 and 10-5 mol tanshinol coating significantly upregulated the nitric oxide level at 14 days of culture, and significantly increased the level of vascular endothelial growth factor at 7 and 14 days of culture (P <0.05). Although it could be found in all β-TCP scaffolds with tanshinol coating, the lumen formation was the maturest in the scaffold with 10-5 mol tanshinol coating. These results suggest the β-TCP scaffolds with tanshinol coating can promote the proliferation and endothelial differentiation of hEPCs, and hold a good cytocompatibility.

Toxicologic pathology plays an important role in the safety evaluation of drugs.The results of toxicologic pathology can answer the basic problems of pathological lesions such as location,severity grading,nature and prognosis,etc.Necropsy and gross pathology examination are important aspects of toxicologic pathology assessment.Procedures typically include preparation for the necropsy,euthanasia procedures,identification and recording all gross lesions,collection of tissues listed in the study protocol,determination of organ weight,as well as tissue fixation so as to be ready for the subsequent tissue processing and histopathology examination.All the procedures must be done in a consistent manner and in accordance with standard operating procedures (SOPs).The present paper briefly introduced the principles of necropsy and gross pathology examination for toxicologic pathology in order to standardize the procedures and to lay foundation for the improvement of the histopathology examination in the field of preclinical safety evaluation of drugs of China.