Preoperative prediction of vessel invasion in locally advanced gastric cancer based on venous phase enhanced CT radiomics and machine learning / 中华放射学杂志

Objective:To evaluate the value of preoperative prediction of vessel invasion (VI) of locally advanced gastric cancer by machine learning model based on the venous phase enhanced CT radiomics features.Methods:A retrospective analysis of 296 patients with locally advanced gastric cancer confirmed by pathology in the First Affiliated Hospital of Zhengzhou University from July 2011 to December 2020 was performed. The patients were divided into VI positive group ( n=213) and VI negative group ( n=83) based on pathological results. The data were divided into training set ( n=207) and test set ( n=89) according to the ratio of 7∶3 with stratification sampling. The clinical characteristics of patients were recorded, and the independent risk factors of gastric cancer VI were screened by multivariate logistic regression. Pyradiomics software was used to extract radiomic features from the venous phase enhanced CT images, and the minimum absolute shrinkage and selection algorithm (LASSO) was used to screen the features, obtain the optimal feature subset, and establish the radiomics signature. Four machine learning algorithms, including extreme gradient boosting (XGBoost), logistic, naive Bayes (GNB), and support vector machine (SVM) models, were used to build prediction models for the radiomics signature and the screened clinical independent risk factors. The efficacy of the model in predicting gastric cancer VI was evaluated by the receiver operating characteristic curve. Results:The degree of differentiation (OR=13.651, 95%CI 7.265-25.650, P=0.003), Lauren′s classification (OR=1.349, 95%CI 1.011-1.799, P=0.042) and CA199 (OR=1.796, 95%CI 1.406-2.186, P=0.044) were independent risk factors for predicting the VI of locally advanced gastric cancer. Based on the venous phase enhanced CT images, 864 quantitative features were extracted, and 18 best constructed radiomics signature were selected by LASSO. In the training set, the area under the curve (AUC) of XGBoost, logistic, GNB and SVM models for predicting gastric cancer VI were 0.914 (95%CI 0.875-0.953), 0.897 (95%CI 0.853-0.940), 0.880 (95%CI 0.832-0.928) and 0.814 (95%CI 0.755-0.873), respectively, and in the test set were 0.870 (95%CI 0.769-0.971), 0.877 (95%CI 0.788-0.964), 0.859 (95%CI 0.755-0.961) and 0.773 (95%CI 0.647-0.898). The logistic model had the largest AUC in the test set. Conclusions:The machine learning model based on the venous phase enhanced CT radiomics features has high efficacy in predicting the VI of locally advanced gastric cancer before the operation, and the logistic model demonstrates the best diagnostic efficacy.

Design and Verification of Lung Diffusion Function Detection System / 中国医疗器械杂志

A lung diffusion function detection system is designed. Firstly, the controllable collection of air, test gas source and calibration gas source was based on single-breath method measurement principle. Secondly, pulmonary diffusing capacity for carbon monoxide (DlCO) was calculated by gas concentration measured by the non-dispersive infrared sensor to measure, the gas flow measured by the differential pressure sensor, and the temperature, humidity and atmospheric pressure sensors to test and evaluate the quantitative detection and evaluation of lung diffusion function. Moreover, a preliminary verification of the lung diffusion function detection system was implemented, and the results showed that the error of the lung carbon monoxide diffusion and the alveolar volume did not exceed 5%. Therefore, the system has high accuracy and is of great value for early screening and accurate assessment of COPD.

Simulation Study on the Influence of Sampling Delay on the Accuracy of Energy Metabolism Measurement / 中国医疗器械杂志

Indirect energy metabolism measurement is the gold standard for providing nutritional support for critical illness. The accuracy of the measurement data directly affects the outcome of the disease. In order to study the influence of sampling delay on the accuracy of energy metabolism measurement under mechanical ventilation, the Matlab/Simulink platform and respiratory electrical model were used for simulation and quantitative analysis. The results show that the error of indirect energy metabolism measurement increases with the increase of sampling delay, the error of sampling delay in mechanical ventilation mode is larger than that of spontaneous breathing, and the error of sampling delay in PCV mode of mechanical ventilation is larger than that in VCV mode. Therefore, there should be different sampling delay compensation strategies under severe mechanical ventilation and its different control modes.

Characteristics of oral methicillin-resistant Staphylococcus epidermidis isolated from dental plaque / 国际口腔科学杂志·英文版

The oral microbial community is widely regarded as a latent reservoir of antibiotic resistance genes. This study assessed the molecular epidemiology, susceptibility profile, and resistance mechanisms of 35 methicillin-resistant Staphylococcus epidermidis (MRSE) strains isolated from the dental plaque of a healthy human population. Broth microdilution minimum inhibitory concentrations (MICs) revealed that all the isolates were nonsusceptible to oxacillin and penicillin G. Most of them were also resistant to trimethoprim (65.7%) and erythromycin (54.3%). The resistance to multiple antibiotics was found to be largely due to the acquisition of plasmid-borne genes. The mecA and dfrA genes were found in all the isolates, mostly dfrG (80%), aacA-aphD (20%), aadD (28.6%), aphA3 (22.9%), msrA (5.7%), and the ermC gene (14.3%). Classical mutational mechanisms found in these isolates were mainly efflux pumps such as qacA (31.4%), qacC (25.7%), tetK (17.1%), and norA (8.6%). Multilocus sequence type analysis revealed that sequence type 59 (ST59) strains comprised 71.43% of the typed isolates, and the eBURST algorithm clustered STs into the clonal complex 2-II(CC2-II). The staphyloccoccal cassette chromosome mec (SCCmec) type results showed that 25 (71.43%) were assigned to type IV. Moreover, 88.66% of the isolates were found to harbor six or more biofilm-associated genes. The aap, atlE, embp, sdrF, and IS256 genes were detected in all 35 isolates. This research demonstrates that biofilm-positive multiple-antibiotic-resistant ST59-SCCmec IV S. epidermidis strains exist in the dental plaque of healthy people and may be a potential risk for the transmission of antibiotic resistance.

Effect of transcutaneous electrical acupoint stimulation on gastric emptying in patients undergoing surgery / 中国针灸

<p><b>OBJECTIVE</b>To observe the effects of transcutaneous electrical acupoint stimulation (TEAS) on gastric emptying in patients undergoing selective surgery based on velocity of gastric emptying by ultrasonography.</p><p><b>METHODS</b>A total of 75 patients with selective operation of subarachnoid block at lower limb in the afternoon were randomly assigned to a TEAS group, a sham group and a control group, 25 patients in each one. All the patients were provided with semi-fluid diet at 8 a.m. The TEAS group was treated with TEAS 5 min after semi-fluid diets at bilateral Zusanli (ST 36) and Neiguan (PC 6) for 30 min, with frequency of 5 Hz and intensity which was 1 mA lower than the tolerance threshold. The sham group patients were stimulated at the same acupoints with current intensity which was 1 mA lower than the sensory threshold. The control group received no treatment. On the day of operation, and ultrasonography was given at time of empty stomach (T0), immediately after the semi-fluid diets (T1), and every 30 min after diets (T2-T6), respectively, to measure the gastric content and emptying time at semire-clining position and right lateral position.</p><p><b>RESULTS</b>The volume of gastric content in the three groups at T3-T6 was significantly less than that at T1 (all<0.05). The volume of gastric content at T4-T6 at semire-clining position in the TEAS group was significantly less than that in the control group and sham group (all<0.05). The volume of gastric content at T5-T6 at right lateral position in the TEAS group was significantly less than that in the control group and sham group (all<0.05). The gastric emptying time in the TEAS group was significantly less than that in the control group and sham group (both<0.05).</p><p><b>CONCLUSION</b>The gastric emptying velocity could be evaluated by ultrasonography. TEAS could improve the velocity of gastric emptying and reduce the gastric emptying time.</p>