Loss of Atg7 in Endothelial Cells Enhanced Cutaneous Wound Healing in a Mouse Model.

BACKGROUND: Emerging evidence has linked autophagy to skin wound healing; however, the underlying cellular and molecular mechanisms remain poorly understood. The present study was designed to determine the role of autophagy in endothelial cell (EC)-mediated skin wound healing in mice. METHODS: Autophagy-related gene (Atg7) in mouse ECs was inactivated by the Cre-loxP system under the control of an EC-specific VE-Cadherin (Cdh5) promoter (Atg7EC-/- mice). Full-thickness skin wounds were created on the dorsum of wild-type (WT), Cdh5-Cre+, floxed Atg7 (Atg7F/F), and Atg7EC-/- mice. Autophagic activity was determined by autophagic flux assay in the primary culture of ECs isolated from these mice. The wound re-epithelialization and angiogenesis was examined by histological analyses. The angiogenic activity of ECs was evaluated by tube formation assay in vitro. EC proliferation was examined by a cell count CCK-8 kit. EC-originated intercellular communication with dermal fibroblasts and keratinocytes was assessed by measuring the effect of EC conditional medium on the growth of keratinocytes and fibroblasts. The levels of VEGF, EGF, bFGF in EC conditional medium were measured by ELISA. RESULTS: Autophagy deficiency in ECs markedly enhanced the re-epithelialization and the wound closure during skin wound healing. However, it has minimal impact on angiogenesis in the wounded skin. Notably, autophagy deficiency in ECs did not affect their proliferation and migration or angiogenic activity per se but enhanced the EC conditional medium-induced proliferation and migration of keratinocytes and fibroblasts. CONCLUSIONS: These results demonstrate for the first time an inhibitory role of autophagy in the EC-originated paracrine regulation of skin wound healing.

Performance of ChatGPT on Chinese Master's Degree Entrance Examination in Clinical Medicine.

BACKGROUND: ChatGPT is a large language model designed to generate responses based on a contextual understanding of user queries and requests. This study utilised the entrance examination for the Master of Clinical Medicine in Traditional Chinese Medicine to assesses the reliability and practicality of ChatGPT within the domain of medical education. METHODS: We selected 330 single and multiple-choice questions from the 2021 and 2022 Chinese Master of Clinical Medicine comprehensive examinations, which did not include any images or tables. To ensure the test's accuracy and authenticity, we preserved the original format of the query and alternative test texts, without any modifications or explanations. RESULTS: Both ChatGPT3.5 and GPT-4 attained average scores surpassing the admission threshold. Noteworthy is that ChatGPT achieved the highest score in the Medical Humanities section, boasting a correct rate of 93.75%. However, it is worth noting that ChatGPT3.5 exhibited the lowest accuracy percentage of 37.5% in the Pathology division, while GPT-4 also displayed a relatively lower correctness percentage of 60.23% in the Biochemistry section. An analysis of sub-questions revealed that ChatGPT demonstrates superior performance in handling single-choice questions but performs poorly in multiple-choice questions. CONCLUSION: ChatGPT exhibits a degree of medical knowledge and the capacity to aid in diagnosing and treating diseases. Nevertheless, enhancements are warranted to address its accuracy and reliability limitations. Imperatively, rigorous evaluation and oversight must accompany its utilization, accompanied by proactive measures to surmount prevailing constraints.

Development and Validation of an Interpretable Machine Learning Model for Early Prognosis Prediction in ICU Patients with Malignant Tumors and Hyperkalemia.

This study aims to develop and validate a machine learning (ML) predictive model for assessing mortality in patients with malignant tumors and hyperkalemia (MTH). We extracted data on patients with MTH from the Medical Information Mart for Intensive Care-IV, version 2.2 (MIMIC-IV v2.2) database. The dataset was split into a training set (75%) and a validation set (25%). We used the Least Absolute Shrinkage and Selection Operator (LASSO) regression to identify potential predictors, which included clinical laboratory indicators and vital signs. Pearson correlation analysis tested the correlation between predictors. In-hospital death was the prediction target. The Area Under the Curve (AUC) and accuracy of the training and validation sets of 7 ML algorithms were compared, and the optimal 1 was selected to develop the model. The calibration curve was used to evaluate the prediction accuracy of the model further. SHapley Additive exPlanations (SHAP) and Local Interpretable Model-agnostic Explanations (LIME) enhanced model interpretability. 496 patients with MTH in the Intensive Care Unit (ICU) were included. After screening, 17 clinical features were included in the construction of the ML model, and the Pearson correlation coefficient was <0.8, indicating that the correlation between the clinical features was small. eXtreme Gradient Boosting (XGBoost) outperformed other algorithms, achieving perfect scores in the training set (accuracy: 1.000, AUC: 1.000) and high scores in the validation set (accuracy: 0.734, AUC: 0.733). The calibration curves indicated good predictive calibration of the model. SHAP analysis identified the top 8 predictive factors: urine output, mean heart rate, maximum urea nitrogen, minimum oxygen saturation, minimum mean blood pressure, maximum total bilirubin, mean respiratory rate, and minimum pH. In addition, SHAP and LIME performed in-depth individual case analyses. This study demonstrates the effectiveness of ML methods in predicting mortality risk in ICU patients with MTH. It highlights the importance of predictors like urine output and mean heart rate. SHAP and LIME significantly enhanced the model's interpretability.

[The roles of CD4+CD25+ T regulatory cells and Foxp3 mRNA expression in the subjects with and without responses to hepatitis B virus vaccination].

OBJECTIVES: To investigate the internal links between immune responses and Tregs and cytokine by the expression of T regulatory cells (Tregs), Foxp3 mRNA of different response groups and the detection of cytokine secretion after hepatitis B vaccination. METHODS: Blood samples were collected in different response groups. Real-time fluorescence quantitative PCR was used to detect the expression of Foxp3 mRNA of peripheral blood mononuclear cells; The surface markers CD4 and CD25 in peripheral-blood mononuclear cells were determined by flow cytometry; ELISA tests were used to detect the production level of phytohemagglutinin (PHA) in peripheral blood mononuclear cells, IL -4, IL-12, IL-18 stimulated by HBsAg and (IFN) gamma. RESULTS: (1) Foxp3 expressions in response group and non-response group were higher before or after PHA and HBsAg were stimulated. Differences were statistically significant (P value less than 0.05) ; (2) In peripheral blood, the percentage of CD4+CD25+ Treg of CD4+ T cells in response group (0.59%+/-0.46%) was obviously lower than those in control group (1.30%+/-1.44%) ; (3) Peripheral blood mononuclear cells stimulated by PHA and HbsAg in each group, the concentration of IFNgamma in non-response group [(11.00+/-9.03) IU/ml] was markedly lower than those in response group [(38.88+/-28.16) IU/ml],and differences were statistically significant (P value less than 0.01); (4) In PHA- or HBsAg-stimulated peripheral-blood mononuclear cells, the concentrations of IL-18, IL-4 and IL-12 had no significant difference. CONCLUSIONS: To some extent, CD4+CD25+Foxp3+ Treg cells may be involved in negative regulation of the immune responses to HBV vaccination. Immune non-response to HBV vaccination may be connected to insufficient secretion of IFNgamma; There was no correlation between the titer of anti-HBs and the expressions of IFNgamma and CD4+CD25+ Foxp3.

Retrospective analysis of nosocomial infections in the intensive care unit of a tertiary hospital in China during 2003 and 2007.

BACKGROUND: Nosocomial infections are a major threat to patients in the intensive care unit (ICU). Limited data exist on the epidemiology of ICU-acquired infections in China. This retrospective study was carried out to determine the current status of nosocomial infection in China. METHODS: A retrospective review of nosocomial infections in the ICU of a tertiary hospital in East China between 2003 and 2007 was performed. Nosocomial infections were defined according to the definitions of Centers for Disease Control and Prevention. The overall patient nosocomial infection rate, the incidence density rate of nosocomial infections, the excess length of stay, and distribution of nosocomial infection sites were determined. Then, pathogen and antimicrobial susceptibility profiles were further investigated. RESULTS: Among 1980 patients admitted over the period of time, the overall patient nosocomial infection rate was 26.8% or 51.0 per 1000 patient days., Lower respiratory tract infections (LRTI) accounted for most of the infections (68.4%), followed by urinary tract infections (UTI, 15.9%), bloodstream (BSI, 5.9%), and gastrointestinal tract (GI, 2.5%) infections. There was no significant change in LRTI, UTI and BSI infection rates during the 5 years. However, GI rate was significantly decreased from 5.5% in 2003 to 0.4% in 2007. In addition, A. baumannii, C. albicans and S. epidermidis were the most frequent pathogens isolated in patients with LRTIs, UTIs and BSIs, respectively. The rates of isolates resistant to commonly used antibiotics ranged from 24.0% to 93.1%. CONCLUSION: There was a high and relatively stable rate of nosocomial infections in the ICU of a tertiary hospital in China through year 2003-2007, with some differences in the distribution of the infection sites, and pathogen and antibiotic susceptibility profiles from those reported from the Western countries. Guidelines for surveillance and prevention of nosocomial infections must be implemented in order to reduce the rate.

Novel Method of 3-Dimensional Graphical Representation for Proteins and Its Application.

In this article, we propose a 3-dimensional graphical representation of protein sequences based on 10 physicochemical properties of 20 amino acids and the BLOSUM62 matrix. It contains evolutionary information and provides intuitive visualization. To further analyze the similarity of proteins, we extract a specific vector from the graphical representation curve. The vector is used to calculate the similarity distance between 2 protein sequences. To prove the effectiveness of our approach, we apply it to 3 real data sets. The results are consistent with the known evolution fact and show that our method is effective in phylogenetic analysis.

PIK3CG single nucleotide polymorphisms are associated with poor responsiveness to clopidogrel and increased risk of ischemia in patients with coronary heart disease.

BACKGROUND: This study explores the associations between PIK3CG single nucleotide polymorphisms (SNPs, rs1129293 and rs17398575) and patient responsiveness to clopidogrel to evaluate the risks of ischemia in patients with coronary heart disease (CHD). METHODS: The study consisted of 513 CHD patients who received clopidogrel as part of antiplatelet therapy, after percutaneous coronary intervention. According to the patient responsiveness to clopidogrel, the subjects were assigned to either clopidogrel-resistant (CR) or clopidogrel-sensitive (CS) groups. CR group was determined by patients' platelet aggregation rate of ≥70% and poor responsiveness to clopidogrel, and CS group by patients' platelet aggregation rates of <70% and good responsiveness to clopidogrel. Polymerase chain reaction using TaqMan probe was employed to detect PIK3CG polymorphism. Haplotype and linkage disequilibrium analyses were performed. Prognosis analysis was performed using the Kaplan-Meier curve. RESULTS: Significant difference was found in genotype and rs1129293 and rs17398575 allele frequency between the CR and CS groups. Haplotype analysis indicated that the frequency of TG allele was higher in the CR group compared with the CS group, and the frequency of CA allele was lower in the CR group compared with the CS group. Patients with rs1129293 CT + TT genotype and T allele, rs1129293 AG + GG genotype and G allele exhibited an increased CR risk. Logistic regression analysis determined hypertension history as an independent risk factor for CR. The Kaplan-Meier curve suggests that distribution curve of cumulative probability nonischemic events was different between patients with rs1129293 and rs17398575 alleles. Stable CHD patients with TT genotype of rs1129293 allele and GG genotype of rs17398575 allele showed poorer prognosis compared to those with other genotypes and patients with acute coronary syndromes. CONCLUSION: A positive correlation may exist between PIK3CG SNPs (rs1129293 and rs17398575) and patients with poor responsiveness to clopidogrel. These findings show that this factor may contribute to an increased risk of ischemia in patients suffering from CHD.

[Comparison of the efficiency of three techniques for labeling human adipose-derived stem cells].

OBJECTIVE: To explore the optimal methods for labeling human adipose-derived stem cells (ASCs). METHODS: ASCs were isolated by collagenase digestion and density gradient centrifugation, and their cell surface markers and ability to differentiate into the adipogenic, chondrogenic, and osteogenic lineages were examined in vitro. Three different cell labeling methods, namely 5 µl DiI, 10 µg/ml BrdU and 50 MOI adenovirus carrying GFP, were used for ASC labeling, and the labeling efficiency were compared at different time points and in different passages using fluorescent microscope. RESULTS: The isolated ASCs were capable of differentiating into adipogenic, osteogenic, chondrogenic lineages with positive stem cell marker expression. At 48 h after DiI staining, 100% of the ASCs emitted red fluorescence in the cytoplasm with fluorescent-negative nuclei, but the fluorescence intensity declined quickly after cell passaging. With 10 µg/ml BrdU, 90% of the cells showed green fluorescence in the cell nuclei at 48 h after the labeling, but the positivity rate also decreased gradually after cell passaging. Cell labeling with GFP adenovirus showed more stable labeling efficiency, and green fluorescence was detected at 24 h after labeling, and even till 5 days later more than 90% of the ASCs remained positive without an obvious attenuation of the fluorescent intensity even after cell passaging. CONCLUSION: All the 3 techniques are applicable for labeling ASCs. Cell labeling with DiI and BrdU can be convenient and economic and well serve the purpose of short-term labeling. Adenovirus carrying GFP gene is the optimal choice for long-term ASC tracing.