Comparative proteomic analysis of vancomycin-sensitive and vancomycin-intermediate resistant Staphylococcus aureus.

PURPOSE: The extensive use of vancomycin has led to the development of Staphylococcus aureus strains with varying degrees of resistance to vancomycin. The present study aimed to explore the molecular causes of vancomycin resistance by conducting a proteomics analysis of subcellular fractions isolated from vancomycin-intermediate resistant S. aureus (VISA) and vancomycin-sensitive S. aureus (VSSA) strains. METHODS: We conducted proteomics analysis of subcellular fractions isolated from 2 isogenic S. aureus strains: strain 11 (VSSA) and strain 11Y (VISA). We used an integrated quantitative proteomics approach assisted by bioinformatics analysis, and comprehensively investigated the proteome profile. Intensive bioinformatics analysis, including protein annotation, functional classification, functional enrichment, and functional enrichment-based cluster analysis, was used to annotate quantifiable targets. RESULTS: We identified 128 upregulated proteins and 21 downregulated proteins in strain 11Y as compared to strain 11. The largest group of differentially expressed proteins was composed of enzymatic proteins associated with metabolic and catalytic activity, which accounted for 32.1% and 50% of the total proteins, respectively. Some proteins were indispensable parts of the regulatory networks of S. aureus that were altered with vancomycin treatment, and these proteins were related to cell wall metabolism, cell adhesion, proteolysis, and pressure response. CONCLUSION: Our proteomics study revealed regulatory proteins associated with vancomycin resistance in S. aureus. Some of these proteins were involved in the regulation of cell metabolism and function, which provides potential targets for the development of strategies to manage vancomycin resistance in S. aureus.

Evaluation of liver function using Gd-EOB-DTPA-enhanced MRI with T1 mapping.

PURPOSE: To evaluate the value of MRI T1 mapping with Gd-EOB-DTPA for assessing liver function. METHODS: Seventy-two patients who underwent Gd-EOB-DTPA-enhanced MRI for focal liver lesions at Beijing Friendship Hospital from August 2020 to March 2022 were prospectively enrolled, and variable-flip-angle T1 mapping was performed before and 20 min after enhancement. The Child-Pugh (C-P) score and albumin-bilirubin (ALBI) grade of liver function were assessed using the clinical data of the patients. Correlation analysis was used to evaluate the correlation between T1 mapping parameters and liver function grading and laboratory tests. Nonparametric tests were used to compare the differences among different liver function groups. The liver function classification efficiency of each image index was evaluated with receiver operating characteristic (ROC) curves. RESULTS: T1post was positively correlated with the C-P grade and the ALBI grade (r = 0.717 and r = 0.652). ΔT1 was negatively correlated with the C-P grade and the ALBI grade (r = -0.790 and r = -0.658). T1post and ΔT1 significantly differed among different liver function grades (p < 0.05). For the C-P grade, T1post and ΔT1 were significantly different between each pair of groups (p < 0.05), and ΔT1 had a better diagnostic efficiency than T1post. For the ALBI grade, ΔT1 and T1post were significantly different between the NLF and ALBI1 groups (p < 0.05), and ΔT1 had a better diagnostic efficacy than T1post. T1post significantly differed between the ALBI1 and ALBI2 + 3 groups (p < 0.05), while ΔT1 had a weak ability to differentiate between these two groups. CONCLUSION: T1post and ΔT1 were strongly correlated with the two liver function grades and can be noninvasive imaging indexes for evaluating liver function.

Noninvasive evaluation of esophageal varices in cirrhotic patients based on spleen hemodynamics: a dual-energy CT study.

OBJECTIVE: To evaluate noninvasively the severity of esophageal varices (EV) in cirrhotic patients using splenic hemodynamics obtained with dual-energy CT. METHODS: We retrospectively analyzed 72 cirrhotic patients with EV between December 2018 and June 2019. Patients were divided into three groups: mild (EV1), medium (EV2), or severe (EV3) EV groups based on severity of EV assessed by endoscopy. An additional control group included 20 patients with normal liver CT. All patients underwent contrast-enhanced dual-energy CT. The iodine weight in spleen (IW-S) was calculated as IW-S = IC-S (iodine concentration in spleen) × V-S (spleen volume). Differences between EV and control groups were analyzed using one-way analysis of variance with Welch's correction. Games-Howell test made further pairwise comparison. The diagnostic value of IW-S on high-risk EV (EV2, EV3, or EV1 with red color sign) was evaluated using the ROC curve. p < 0.05 indicated statistical significance. RESULTS: The overall difference of IW-S between the control and EV groups was statistically significant (p < 0.001). Patients with more severe EV had higher IW-S values. Pairwise comparisons showed that except for control vs. EV1 groups, the IW-S between any other two groups was significantly different (p < 0.05). With a cutoff value at 1087 mg, the AUC for using IW-S for the detection of high-risk EV was 0.87 (95% CI 0.77~0.94). Sensitivity and specificity were 84.9% and 84.2%, respectively. CONCLUSION: IW-S obtained with dual-energy CT can noninvasively predict EV severity. KEY POINTS: • A higher iodine weight in spleen (IW-S) was observed in case of severe esophageal varices. • Cirrhotic patients have significantly higher IW-S than normal-liver patients. • IW-S in dual-energy CT maybe used to evaluate the severity of EV.

Assessing Liver Hemodynamics in Children With Cholestatic Cirrhosis by Use of Dual-Energy Spectral CT.

OBJECTIVE. The purpose of this study was to evaluate the value of dual-energy CT (DECT) in assessing liver hemodynamics in children with cholestatic cirrhosis. MATERIALS AND METHODS. The cases of 60 children with cholestatic cirrhosis (study group) and 15 children with inherited metabolic diseases but normal liver function (control group) were retrospectively evaluated. Enhanced CT scans were obtained in spectral imaging mode. Iodine concentration (IC) of hepatic parenchyma in the arterial phase (ICA) and portal venous phase (ICP) was measured on iodine-water material decomposition images. The hepatic arterial iodine fraction (AIF) was calculated as: AIF = ICA / ICP. The ICA, ICP, and AIF of children in the control and study groups were analyzed by one-way ANOVA and post hoc test with Bonferroni correction. The radiation dose was recorded. RESULTS. There were differences in ICA and AIF between the control and study groups. The values in patients in the Child-Pugh class C group were the highest and those in the control group the lowest (p < 0.05). Statistically significant differences in ICP were not found (p > 0.05). Specifically, the multiple comparison results indicated that there were differences in both ICA and AIF in most of the groups (p < 0.05). The volume CT dose index value for all patients was the same at 10.14 mGy for each enhanced phase, and the total dose-length product varied between 402.68 and 679.18 mGy-cm. CONCLUSION. ICA and AIF obtained at dual-energy CT can be used as semiquantitative indicators to evaluate the liver hemodynamics of children with cholestatic cirrhosis.

8-Week Basic Military Training Improves Adiponectin Multimer Ratio in Healthy Young Males.

To investigate the effect of exercise on adiponectin in young healthy human males, we examined serum total adiponectin and high-molecular-weight (HMW) adiponectin in newly recruited male soldiers who participated in an 8-week basic military training (BMT). A total of 95 males (mean age, 18.79±1.50 years) were sampled from among 1,100 new male army recruits in China. Participants were separated into 3 groups according to their body mass index (BMI): overweight group (BMI: 24.9 kg/m2 to<30 kg/m2; n=26); normal-weight group (BMI: 18.5 kg/m2 to<24.9 kg/m2; n=40); and underweight group (BMI:<18.5 kg/m2; n=29). Anthropometric measurements, fasting serum total adiponectin, HMW adiponectin, and lipid profiles were recorded at baseline and at the end of the 8-week BMT. After the 8-week BMT, the HMW/total adiponectin ratio (HMW/total ratio) and HDL cholesterol improved significantly (p<0.001 and p<0.001, respectively). HMW/total ratio showed significant correlations with HDL cholesterol. Our study suggests that an 8-week BMT can improve the HMW/total ratio in healthy young males regardless of their BMI and anthropometry. Both HMW/total ratio and HDL cholesterol can serve as potential biomarkers for assessing the efficacy of exercise and may have metabolic benefits for preventing obesity and obesity-related disease.

Behind BMI: The Potential Indicative Role of Abdominal Ectopic Fat on Glucose Metabolism.

INTRODUCTION: The purpose of this study was to compare the difference in abdominal fat distribution between different metabolic groups and find the ectopic fat with the most risk significance. METHODS: A total of 98 subjects were enrolled; there were 53 cases in the normal glucose metabolism group and 45 cases in the abnormal glucose metabolism group. Chemical shift-encoded magnetic resonance imaging was applied for quantification of pancreatic fat fraction (PFF) and hepatic fat fraction (HFF), subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT). The correlation and the difference of fat distribution between different metabolism groups were analyzed. The receiver operating characteristic (ROC) curve was used to analyze the suggestive effect of different body fat fraction. RESULTS: Correlation analysis showed that body mass index (BMI) had the strongest correlation with fasting insulin (r = 0.473, p < 0.001), HOMA-IR (r = 0.363, p < 0.001), and C-reactive protein (r = 0.245, p < 0.05). Pancreatic fat has a good correlation with fasting blood glucose (r = 0.247, p < 0.05) and HbA1c (r = 0.363, p < 0.001). With the increase of BMI, PFF, VAT, and SAT showed a clear upward trend, but liver fat was distributed relatively more randomly. The pancreatic fat content in the abnormal glucose metabolism group is significantly higher than that in the normal group, and pancreatic fat is also a reliable indicator of abnormal glucose metabolism, especially in the normal and overweight groups (the area under the curve was 0.859 and 0.864, respectively). CONCLUSION: MR-based fat quantification techniques can provide additional information on fat distribution. There are differences in fat distribution among people with different metabolic status. People with more severe pancreatic fat deposition have a higher risk of glucose metabolism disorders.

Superiority of spleen stiffness on two-dimensional magnetic resonance elastography over liver stiffness and serum tests in assessing portal hypertension in chronic liver disease.

Background: The value of magnetic resonance elastography (MRE) in portal hypertension (PH) has yet to be determined in the context of chronic liver disease (CLD). This study examined the value of MRE for the prediction of hepatic venous pressure gradient (HVPG) and high-risk esophageal varices (EVs) in a CLD cohort with a generally high HVPG. Methods: Patients with CLD who underwent both HVPG measurement and two-dimensional MRE examination at Beijing Friendship Hospital between April 2018 and March 2022 were prospectively included. Two-dimensional MRE was performed within the liver and spleen. Endoscopy results and laboratory parameters were collected. Some selected published serum markers were calculated, including fibrosis 4, aspartate aminotransferase-to-platelet ratio index, and King's score. The efficacy of the parameters for assessing PH was analyzed by using the Pearson correlation coefficient, linear and logistic regression, and receiver operating characteristic curve analyses. Results: A total of 48 patients were included. The mean HVPG was 16.8±5.8 mmHg. Among these patients, 47 patients had PH (HVPG >5 mmHg), and 43 patients had clinically significant PH (HVPG ≥10 mmHg). Among the parameters associated with HVPG, the strongest correlation was found for spleen stiffness (SS) (R=0.638; P<0.001). In multiple regression analyses, SS was independently associated with an elevated HVPG and high-risk EVs. The areas under the receiver operating characteristic curve of SS for identifying patients with an HVPG ≥16 mmHg, HVPG ≥20 mmHg, and high-risk EVs were 0.790, 0.822, and 0.886, respectively, which were higher than those of liver stiffness (LS) and serum markers but slightly inferior to that of fibrosis 4 (area under the receiver operating characteristic curve =0.844) in identifying an HVPG ≥16 mmHg. SS cutoff values of 9.5, 10.05, and 9.9 kPa were selected to rule out the presence of an HVPG ≥16 mmHg, HVPG ≥20 mmHg, and high-risk EVs (sensitivity: 100%, 100%, and 100%, respectively; specificity: 45.5%, 50%, and 60%, respectively). Conclusions: In patients with generally high HVPG, SS measured by two-dimensional MRE may be a better predictor of HVPG values and high-risk EVs than LS and serum markers.

The timing phase affected the inconsistency of APHE subtypes of liver observations in patients at risk for HCC on the multi-hepatic arterial phase imaging.

OBJECTIVE: To investigate whether liver observations in patients at risk for hepatocellular carcinoma (HCC) display inconsistent arterial phase hyperenhancement (APHE) subtypes on the multi-hepatic arterial phase imaging (mHAP) and to further investigate factors affecting inconsistent APHE subtype of observations on mHAP imaging. METHODS: From April 2018 to June 2021, a total of 141 patients at high risk of HCC with 238 liver observations who underwent mHAP MRI acquisitions were consecutively included in this retrospective study. Two experienced radiologists reviewed individual arterial phase imaging independently and assessed the enhancement pattern of each liver observation according to LI-RADS. Another two experienced radiologists identified and recorded the genuine timing phase of each phase independently. When a disagreement appeared between the two radiologists, another expert participated in the discussion to get a final decision. A separate descriptive analysis was used for all observations scored APHE by the radiologists. The Kappa coefficient was used to determine the agreement between the two radiologists. Univariate analysis was performed to investigate the factors affecting inconsistent APHE subtype of liver observations on mHAP imaging. RESULTS: The interobserver agreement was substantial to almost perfect agreement on the assessment of timing phase (κ = 0.712-0.887) and evaluation of APHE subtype (κ = 0.795-0.901). A total of 87.8% (209/238) of the observations showed consistent nonrim APHE and 10.2% (24/238) of the observations showed consistent rim APHE on mHAP imaging. A total of 2.1% (5/238) of the liver observations were considered inconsistent APHE subtypes, and all progressed nonrim to rim on mHAP imaging. 87.9% (124/141) of the mHAP acquisitions were all arterial phases and 12.1% (17/141) of the mHAP acquisitions obtained both the arterial phase and portal venous phase. Univariate analysis was performed and found that the timing phase of mHAP imaging affected the consistency of APHE subtype of liver observations. When considering the timing phase and excluding the portal venous phase acquired by mHAP imaging, none of the liver observations showed inconsistent APHE subtypes on mHAP imaging. CONCLUSION: The timing phase which mHAP acquisition contained portal venous phase affected the inconsistency of APHE subtype of liver observations on mHAP imaging. When evaluating the APHE subtype of liver observations, it's necessary to assess the timing of each phase acquired by the mHAP technique at first.

Computed tomography-based body composition parameters can predict short-term prognosis in ulcerative colitis patients.

OBJECTIVES: Emerging evidence suggests a potential relationship between body composition and short-term prognosis of ulcerative colitis (UC). Early and accurate assessment of rapid remission based on conventional therapy via abdominal computed tomography (CT) images has rarely been investigated. This study aimed to build a prediction model using CT-based body composition parameters for UC risk stratification. METHODS: In total, 138 patients with abdominal CT images were enrolled. Eleven quantitative parameters related to body composition involving skeletal muscle mass, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were measured and calculated using a semi-automated segmentation method. A prediction model was established with significant parameters using a multivariable logistic regression. The receiver operating characteristic (ROC) curve was plotted to evaluate prediction performance. Subgroup analyses were implemented to evaluate the diagnostic efficiency of the prediction model between different disease locations, centers, and CT scanners. The Delong test was used for statistical comparison of ROC curves. RESULTS: VAT density, SAT density, gender, and visceral obesity were significantly statistically different between remission and invalidation groups (all p < 0.05). The accuracy, sensitivity, specificity, and area under the ROC curve (AUC) of the prediction model were 82.61%, 95.45%, 69.89%, and 0.855 (0.792-0.917), respectively. The positive predictive value and negative predictive value were 70.79% and 93.88%, respectively. No significant differences in the AUC of the prediction model were found in different subgroups (all p > 0.05). CONCLUSIONS: The predicting model constructed with CT-based body composition parameters is a potential non-invasive approach for short-term prognosis identification and risk stratification. Additionally, VAT density was an independent predictor for escalating therapeutic regimens in UC cohorts. CRITICAL RELEVANCE STATEMENT: The CT images were used for evaluating body composition and risk stratification of ulcerative colitis patients, and a potential non-invasive prediction model was constructed to identify non-responders with conventional therapy for making therapeutic regimens timely and accurately. KEY POINTS: • CT-based prediction models help divide patients into invalidation and remission groups in UC. • Results of the subgroup analysis confirmed the stability of the prediction model with a high AUC (all > 0.820). • The visceral adipose tissue density was an independent predictor of bad short-term prognosis in UC.

Quantitative Evaluation of Nonalcoholic Fatty Liver in Rat by Material Decomposition Techniques using Rapid-switching Dual Energy CT.

RATIONALE AND OBJECTIVES: To evaluate the material decomposition (MD) techniques in rapid kVp switching dual-energy CT (rsDECT) for quantifying liver fat content in rats with nonalcoholic fatty liver. MATERIALS AND METHODS: Fifty male Sprague-Dawley (SD) rats were divided into study group (n=37) and control group (n = 13) and underwent rsDECT examination at different intervals. All the data analysis was performed using AW4.7 workstation. The fat contents under the traditional fat(water), fat(blood), and fat(muscle) material decomposition (MD) images and the fat volume fraction (FVF) from the liver fat maps generated using multi-material decomposition (MMD) technique were measured. The pathological grades (grade 0, 1, 2 and 3) of fatty liver were determined after euthanasia. The measurement differences among different grades and the correlation of measurements with different grades was analyzed using ANOVA and Spearman correlation, respectively. A receiver operating characteristics (ROC) curve was used to analyze the diagnostic efficacies of fat contents and FVF. RESULTS: There were statistically significant differences in FVF and fat contents under fat(water), fat(blood), fat(muscle) based MD images among different grades. These values correlated well with the pathological grades (R-value: 0.90, 0.75, 0.79, 0.80, all p <0.001), with FVF having the highest correlation. The area-under-the-curve in ROC of using FVF was the highest, with the cut-off value of 0.92 for sensitivity of 89.2% and specificity of 100%. CONCLUSION: The rsDECT MD techniques could quantitatively evaluate the fat content of fatty liver in rat, with the FVF from MMD having the highest correlation with pathological grades.

Non-invasive evaluation of esophageal varices in patients with liver cirrhosis using low-dose splenic perfusion CT.

PURPOSE: To assess the value of splenic hemodynamic parameters measured using low-dose perfusion CT in the noninvasive evaluation of esophageal varices (EV) in patients with liver cirrhosis. METHODS: We retrospectively studied 43 cirrhotic patients with EV, which were divided into mild (EV1), moderate (EV2) and severe (EV3) groups. 14 patients with normal liver function and no EV were selected as the control group. All patients underwent low-dose splenic perfusion CT and radiation dose were recorded. Spleen perfusion parameters, including blood volume (BV), blood flow (BF) and permeability surface (PS), were obtained. The volume of the spleen (V-S) was measured. The total blood volume of the spleen (BV-S) was obtained using the product of V-S and BV. The measurement differences among the four groups were analyzed using ANOVA with Welch correction. Least Significant Difference (LSD) was used for the multiple comparison. P < 0.05 was considered statistically significant. RESULTS: There were statistically significant differences in BV, BF, PS, V-S, and BV-S among different groups (p < 0.05). PS, V-S, and BV-S were higher, and BV and BF were lower in the study groups than those in the control group. There was a statistically significant difference between EV2 and EV1 groups, and EV2 and EV3 groups in BV and BF. The average dose-length product (DLP) was 1286.41 ± 261.15 mGy*cm, and the effective radiation dose（Deff）was 19.30 ± 3.92 mSv. CONCLUSION: The splenic perfusion parameters obtained in the low-dose splenic perfusion CT could be used to noninvasively evaluate the degrees of EV in cirrhotic patients.

Automated segmentation of liver segment on portal venous phase MR images using a 3D convolutional neural network.

OBJECTIVE: We aim to develop and validate a three-dimensional convolutional neural network (3D-CNN) model for automatic liver segment segmentation on MRI images. METHODS: This retrospective study evaluated an automated method using a deep neural network that was trained, validated, and tested with 367, 157, and 158 portal venous phase MR images, respectively. The Dice similarity coefficient (DSC), mean surface distance (MSD), Hausdorff distance (HD), and volume ratio (RV) were used to quantitatively measure the accuracy of segmentation. The time consumed for model and manual segmentation was also compared. In addition, the model was applied to 100 consecutive cases from real clinical scenario for a qualitative evaluation and indirect evaluation. RESULTS: In quantitative evaluation, the model achieved high accuracy for DSC, MSD, HD and RV (0.920, 3.34, 3.61 and 1.01, respectively). Compared to manual segmentation, the automated method reduced the segmentation time from 26 min to 8 s. In qualitative evaluation, the segmentation quality was rated as good in 79% of the cases, moderate in 15% and poor in 6%. In indirect evaluation, 93.4% (99/106) of lesions could be assigned to the correct segment by only referring to the results from automated segmentation. CONCLUSION: The proposed model may serve as an effective tool for automated anatomical region annotation of the liver on MRI images.

In vitro and in vivo assessment of an intelligent artificial anal sphincter in rabbits.

Artificial sphincters have been developed for patients with fecal incontinence, but finding a way to make such sphincters more "intelligent" remains a problem. We assessed the function of a novel intelligent artificial anal sphincter (IAAS) in vitro and in vivo in rabbits. After the prosthesis was activated, rabbits were continent of feces during 81.4% of the activation time. The fecal detection unit provided 100% correct signals on stool in vitro and 65.7% in vivo. The results indicated that the IAAS could efficiently maintain continence and detect stool; however, the IAAS is still in the preliminary experimental stage and more work is needed to improve the system.

Saliency-based 3D convolutional neural network for categorising common focal liver lesions on multisequence MRI.

BACKGROUND: The imaging features of focal liver lesions (FLLs) are diverse and complex. Diagnosing FLLs with imaging alone remains challenging. We developed and validated an interpretable deep learning model for the classification of seven categories of FLLs on multisequence MRI and compared the differential diagnosis between the proposed model and radiologists. METHODS: In all, 557 lesions examined by multisequence MRI were utilised in this retrospective study and divided into training-validation (n = 444) and test (n = 113) datasets. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the performance of the model. The accuracy and confusion matrix of the model and individual radiologists were compared. Saliency maps were generated to highlight the activation region based on the model perspective. RESULTS: The AUC of the two- and seven-way classifications of the model were 0.969 (95% CI 0.944-0.994) and from 0.919 (95% CI 0.857-0.980) to 0.999 (95% CI 0.996-1.000), respectively. The model accuracy (79.6%) of the seven-way classification was higher than that of the radiology residents (66.4%, p = 0.035) and general radiologists (73.5%, p = 0.346) but lower than that of the academic radiologists (85.4%, p = 0.291). Confusion matrices showed the sources of diagnostic errors for the model and individual radiologists for each disease. Saliency maps detected the activation regions associated with each predicted class. CONCLUSION: This interpretable deep learning model showed high diagnostic performance in the differentiation of FLLs on multisequence MRI. The analysis principle contributing to the predictions can be explained via saliency maps.

Evaluation on Heterogeneity of Fatty Liver in Rats: A Multiparameter Quantitative Analysis by Dual Energy CT.

RATIONALE AND OBJECTIVES: To investigate the value of using rapid kVp switching dual energy computed tomography (rsDECT) for the multi-parameter analysis of the heterogeneity of fatty liver in rat. MATERIALS AND METHODS: Twenty-four male rats were randomly divided into experimental (n = 16) and control (n = 8) groups. Four rats in the experimental group and two in the control group were examined by rsDECT every 3 weeks starting from week 8. The liver fat contents (LFC) of the left and right liver lobes were measured on the fat(water)-based material decomposition images to calculate fat content and CT value of liver and spleen were measured on the 70keV monochromatic images to calculate the liver-to-spleen CT value ratio [(L/S)70 keV] and difference at 70keV[(L-S)70 keV], and the spectral curve slopes of the left and right liver lobes (Slope-L, Slope-R). Measurements were evaluated statistically. RESULTS: The statistical analysis showed that the (L/S)70 keV, (L-S)70 keV, Slope and LFC in the different fatty liver groups were all significantly different (p < 0.05). Pearson correlation analysis results showed that the rsDECT results of the left and right liver lobes correlated with the fat percentage from pathological analysis (p < 0.05), with the left liver lobe having better correlation. Paired t-tests showed that the fat percentage of the left liver lobe was significantly higher than that of the right one, while (L/S)70 keV, and (L-S)70 keV were significantly lower. Diagnostic analysis using ROC curve showed that the areas under the curves with parameters of the left liver lobe were also greater than those of the right liver lobe. CONCLUSION: rsDECT multi-parameter imaging could quantitatively evaluate the heterogeneity of fat deposition in the liver, providing valuable information for the accurate and effective assessment of the heterogeneity of fatty liver.

[Preliminary effect of VEGF promoter-driven recombinant adenovirus containing double suicide genes on apoptosis of human gastric carcinoma cells].

OBJECTIVE: To study the effect of the adenovirus containing CD/TK fusion gene controlled by the human vascular endothelial growth factor (VEGF) promoter on apoptosis of human gastric carcinoma cells SGC-7901. METHODS: VEGF-expressing SGC-7901 cells were infected by the recombinant adenovirus Ad-VEGFP-CD/TK, and the infection efficiencies were observed with fluorescence microscopy. The toxic effect and intracellular calcium concentration induced by 5-fluorocytosine (5-FC) and ganciclovic (GCV) were determined by light microscopy, electron microscopy and flow cytometry. RESULTS: The transfection efficiency of the recombinant adenovirus in SGC-7901 cells increased with the viral titer. At the multiplicity of infection (MOI) of 100, 5-FC and GCV could induce apoptosis of SGC-7901 cells within a given dose range in a dose- and time-dependent manner, and apoptotic changes of the cells were observed with electron microscopy. Apoptotic peak was also detected by flow cytometry. Cell cycle analysis revealed increased cell percentage in G(0)-G(1) phase and decreased percentage of cells in G(2)-M and S phases in response to treatment with the pro-drugs, which also induced marked elevation of intracellular calcium concentration in the infected cells. CONCLUSIONS: CD/TK fusion gene system driven by VECF promoter selectively induces apoptosis of VEGF-expressing SGC-7901 cells, the action of which is probably mediated by intracellular calcium variation.