ObjectiveTo investigate the application value of a machine learning model based on preoperative clinical indicators in predicting the risk of hypoalbuminemia after partial hepatectomy. MethodsA retrospective analysis was performed for the clinical data of 700 patients who underwent partial hepatectomy in Nanfang Hospital， Southern Medical University， from January 2018 to January 2023， including demographic data， history of underlying diseases， tumor characteristics， preoperative laboratory markers， and perioperative indicators. The research data were divided into a training set and a test set at a ratio of 7∶3. The two-independent-samples t test was used for comparison of normally distributed continuous data between two groups； the two-independent-samples Wilcoxon rank-sum test was used for comparison of continuous data with skewed distribution between two groups； the chi-square test or the Fisher’s exact test was used for comparison of categorical data between two groups. The least absolute shrinkage and selection operator （LASSO） regression analysis was used to identify characteristic variables， and 7 machine learning algorithms were used to construct predictive models， i.e.， logistic regression， decision tree， artificial neural network， K-nearest neighbors （KNN）， support vector machine， eXtreme gradient boosting， and light gradient boosting machine. The receiver operating characteristic （ROC） curve and the area under the ROC curve （AUC） were used to assess the discriminatory ability of models， and the DeLong test was used for comparison of AUC. The calibration curve and decision curve analysis were used to assess the calibration and clinical practicability of models， and the models were compared with albumin-bilirubin （ALBI） score and Model for End-Stage Liver Disease （MELD） score. SHapley Additive exPlanations （SHAP） were used to interpret the key influencing factors for the optimal model. ResultsA total of 700 patients were finally enrolled， 283 （40.42%） developed hypoalbuminemia after surgery. The LASSO regression analysis identified 8 predictive factors of age， hepatitis B， fatty liver， blockade time， preoperative albumin （Alb）， time of operation， intraoperative blood loss， and preoperative aspartate aminotransferase （AST）. Among the 7 machine learning models， the KNN model showed the best overall predictive performance， with an AUC of 0.835 （95% confidence interval： 0.781 — 0.889）， a sensitivity of 84.0%， and a specificity of 65.5% in the test set. ALBI and MELD scores had an AUC of 0.652 and 0.524， respectively， and the KNN model had a better predictive performance than these two scores （Z=5.309 and 8.945， both P <0.001）. The calibration curve showed good consistency between predicted probabilities and actual incidence rates， and the decision curve analysis showed that the KNN model had net clinical benefit across a wide threshold range. The SHAP analysis showed that preoperative Alb， hepatitis B， time of operation， and age were the most significant influencing factors， and a synergistic effect was observed between hepatitis B and age/time of operation. ConclusionThe KNN machine learning model constructed based on preoperative clinical indicators can effectively predict the risk of hypoalbuminemia after partial hepatectomy and has a better performance than traditional scoring models， which provides a reference for the early identification of high-risk patients in clinical practice.

Objective:To investigate the clinical characteristics of non-typhoidal Salmonella（NTS）enteritis in children and the drug resistance of NTS strains.Methods:The clinical data of 138 children who were hospitalized in Children's Hospital Affiliated to Xi'an Jiaotong University from 2022 to 2023 with diarrhea as the main complaint and NTS detected in stool culture were analyzed retrospectively, and the clinical characteristics and drug resistance were summarized.Results:Among 138 children with NTS enteritis，89 were males and 49 were females，with a male-to-female sex ratio of 1.81∶1 and an average age of 1.9（1.0,3.6）years，with a high incidence rate in June,July and August.Seventeen（12.31%）cases had a history of suspected unclean diet before illness.All the children had diarrhea symptoms with changes in fecal frequency and character，including 74 cases of pus and bloody stool，119 cases of mucus stool，and 70 cases of watery stool.One hundred and twenty-five（90.57%）cases had fever.Among 138 cases of fecal culture,there were 47 (34.05%) strains of Salmonella typhimurium,36(26.09%) strains of Salmonella enteritidis,and 55(39.85%) strains of other serotypes of Salmonella .One hundred and twenty-two（88.40%）NTS strains were resistant to more than one antimicrobial agent，and 29（21.01 %）were multi-drug resistant.The resistance rates to ampicillin，ampicillin/sulbactam，ceftriaxone，trimethoprim/sulfamethazole，ceftazidime，cefepime and piperacillin/tazobactam were 73.91%，71.01%，29.71%，29.71%，23.19%，11.59%，and 3.62%，respectively.All strains were sensitive to carbapenem antibiotics（meropenem，imipenem，and ertapenem）.The drug resistance rates of Salmonella typhimurium to ceftazidime and trimethoprim/sulfamethoxazole were higher than those of Salmonella enteritidis（38.30% vs 8.33%），the difference was statistically significant ( P < 0.05). Conclusion:Infants and young children are the high-incidence group of NTS enteritis，with the peak incidence period being from June to August each year，manifested by mucus-pus-blood stools, abdominal pain, vomiting，fever and other symptoms.Reasonable selection of antibiotics in time according to the local epidemic strains,changes of antimicrobial resistance and the results of drug sensitivity test of strains can effectively resist infection and reduce the production of drug-resistant beads.

Objective:To investigate the clinical characteristics of non-typhoidal Salmonella（NTS）enteritis in children and the drug resistance of NTS strains.Methods:The clinical data of 138 children who were hospitalized in Children's Hospital Affiliated to Xi'an Jiaotong University from 2022 to 2023 with diarrhea as the main complaint and NTS detected in stool culture were analyzed retrospectively, and the clinical characteristics and drug resistance were summarized.Results:Among 138 children with NTS enteritis，89 were males and 49 were females，with a male-to-female sex ratio of 1.81∶1 and an average age of 1.9（1.0,3.6）years，with a high incidence rate in June,July and August.Seventeen（12.31%）cases had a history of suspected unclean diet before illness.All the children had diarrhea symptoms with changes in fecal frequency and character，including 74 cases of pus and bloody stool，119 cases of mucus stool，and 70 cases of watery stool.One hundred and twenty-five（90.57%）cases had fever.Among 138 cases of fecal culture,there were 47 (34.05%) strains of Salmonella typhimurium,36(26.09%) strains of Salmonella enteritidis,and 55(39.85%) strains of other serotypes of Salmonella .One hundred and twenty-two（88.40%）NTS strains were resistant to more than one antimicrobial agent，and 29（21.01 %）were multi-drug resistant.The resistance rates to ampicillin，ampicillin/sulbactam，ceftriaxone，trimethoprim/sulfamethazole，ceftazidime，cefepime and piperacillin/tazobactam were 73.91%，71.01%，29.71%，29.71%，23.19%，11.59%，and 3.62%，respectively.All strains were sensitive to carbapenem antibiotics（meropenem，imipenem，and ertapenem）.The drug resistance rates of Salmonella typhimurium to ceftazidime and trimethoprim/sulfamethoxazole were higher than those of Salmonella enteritidis（38.30% vs 8.33%），the difference was statistically significant ( P < 0.05). Conclusion:Infants and young children are the high-incidence group of NTS enteritis，with the peak incidence period being from June to August each year，manifested by mucus-pus-blood stools, abdominal pain, vomiting，fever and other symptoms.Reasonable selection of antibiotics in time according to the local epidemic strains,changes of antimicrobial resistance and the results of drug sensitivity test of strains can effectively resist infection and reduce the production of drug-resistant beads.

Objective:To analyze the sensitivity and specificity of SARS-CoV-2 nucleic acid testing in 20 348 close contacts of COVID-19 cases in different prevention and control stages in Guangzhou and to provide scientific evidence for optimizing epidemic response strategies.Methods:A total of 20 348 close contacts of COVID-19 cases in Guangzhou were traced between February 21 and September 22,2020. All the close contacts were tested for the nucleic acid of SARS-CoV-2. The sensitivity and specificity of nucleic acid testing and diagnosis in the different prevention and control stages were compared.Results:In 20 348 close contacts, 12 462 were males (61.24%), the median ( P 25, P 75) of age of them was 31.0 years (23.0,43.0), the median number ( P 25, P 75) of nucleic acid testing for them was 2.0 (1.0,3.0), and the median ( P 25, P 75) of their quarantine days was 12.0 (8.0,13.0) days, respectively. A total of 256 COVID-19 cases were confirmed in the close contacts after seven nucleic acid tests. In the 1 st, 2 nd, 3 rd and 7 th nucleic acid testing, the sensitivity and specificity were 69.14% and 99.99% (177 cases confirmed), 89.84% and 99.99% (230 cases confirmed), 97.27% and 99.99% (249 cases confirmed), and 100.00% and 99.98%, respectively. In the three stages of COVID-19 prevention and control in China: domestic case stage, imported case stage, and imported case associated local epidemic stage, the sensitivity of the 1 st nucleic acid testing was 70.68%, 68.00% and 67.35%, and the specificity was 99.98%, 100.00% and 100.00%, respectively. Conclusions:The sensitivity of nucleic acid testing in the close contacts at the different stages were consistent with slight decrease, which might be related to the increased proportion of asymptomatic infections in the late stage of epidemic prevention and control with COVID-19 in Guangzhou. It is suggested to give three nucleic acid tests to improve the sensitivity and reduce false negative risk.

OBJECTIVETo detect the expression of IGF1R and estrogen receptor, and to explore the relationship between their expression and the pathological complete response (pCR) rate of neoadjuvant chemotherapy (docetaxel plus epirubicin) in breast cancer patients.

METHODSWe selected 139 women with breast cancer who underwent neoadjuvant chemotherapy (docetaxel plus epirubicin), and detected the expression of IGF1R and estrogen receptor in the samples taken before chemotherapy by Immunohistochemistry. The association between their expression and pCR rate of neoadjuvant chemotherapy was analyzed.

RESULTSAmong the 139 cases, IGF1R was highly expressed in 45.3% (63/139) cases, and ER was positively expressed in 62.6% (87/139) cases. IGF1R was highly expressed in 54.0% (47/87) of the ER+ cases, significantly higher than that of ER- cases (30.8%, P<0.01). The overall pCR rate of all the 139 patients who received docetaxel plus epirubicin as neoadjuvant chemotherapy was 10.1% (14/139). The pCR rate was 19.2% (10/52) of the ER- patients and 4.6% (4/87) of the ER+ patients (P<0.05). The pCR rate was 10.5% (8/76) in the patients with low IGF1R expression and 9.5% (6/63) in the patients with high IGF1R expression (P>0.05). The patients with negative expression of ER and high expression of IGF1R showed the highest pCR rate (31.2%, P<0.01).

CONCLUSIONSBreast cancer patients with negative expression of ER and high expression of IGF1R are more sensitive to neoadjuvant chemotherapy of docetaxel plus epirubicin, and their pCR rate is significantly higher than that of other patients.

Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Biomarkers, Tumor ; Breast Neoplasms ; drug therapy ; metabolism ; Epirubicin ; administration & dosage ; Female ; Humans ; Immunohistochemistry ; Neoadjuvant Therapy ; Receptors, Estrogen ; metabolism ; Receptors, Somatomedin ; metabolism ; Taxoids ; administration & dosage