1.The effect of wza gene deletion in Klebsiella pneumoniae on capsule formation and bacteriophage sensitivity
Zheng FAN ; Hongbo LIU ; Yuchen CHEN ; Xiaohu CUI ; Zhoufei LI ; Tongtong FU ; Jing YUAN
Chinese Journal of Preventive Medicine 2024;58(7):992-997
Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.
2.Expression, purification and functional validation of phage depolymerase from hypervirulent Klebsiella pneumoniae serotype K1
Zheng FAN ; Yuchen CHEN ; Hongbo LIU ; Xiaohu CUI ; Zhoufei LI ; Tongtong FU ; Jing YUAN
Chinese Journal of Preventive Medicine 2024;58(9):1348-1353
Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.
3.The effect of wza gene deletion in Klebsiella pneumoniae on capsule formation and bacteriophage sensitivity
Zheng FAN ; Hongbo LIU ; Yuchen CHEN ; Xiaohu CUI ; Zhoufei LI ; Tongtong FU ; Jing YUAN
Chinese Journal of Preventive Medicine 2024;58(7):992-997
Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.
4.Expression, purification and functional validation of phage depolymerase from hypervirulent Klebsiella pneumoniae serotype K1
Zheng FAN ; Yuchen CHEN ; Hongbo LIU ; Xiaohu CUI ; Zhoufei LI ; Tongtong FU ; Jing YUAN
Chinese Journal of Preventive Medicine 2024;58(9):1348-1353
Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.
5.Clinical study on early recognition of hepatitis B cirrhosis by two-dimensional shear wave elastography
Yunling FAN ; Yuchen YANG ; Haohao YIN ; Wen SHEN ; Yuli ZHU
Journal of Chinese Physician 2024;26(4):494-498
Objective:To evaluate the feasibility of using two-dimensional shear wave elastography (2D-SWE) based liver and spleen elastic hardness (L/S-SWE) in patients with liver cirrhosis, and to determine the exclusion and diagnostic thresholds for early identification of liver cirrhosis.Methods:A total of 574 patients with chronic hepatitis B (hepatitis B for short) were included in this study. The clinical characteristics, L-SWE and S-SWE of the patients were collected, and the differences between cirrhosis group ( n=311) and non cirrhosis group ( n=263) were analyzed. The success rate and stability of liver and spleen elastic surgery were evaluated in two groups. The receiver operating characteristic (ROC) curve was used to analyze the efficacy of L-SWE, S-SWE, aspartate aminotransferase to platelet ratio index (APRI) alone and in combination in diagnosing liver cirrhosis. By analyzing the ROC curve, the double threshold for excluding and diagnosing liver cirrhosis was determined. Results:There was a statistically significant difference in platelet count and APRI between the cirrhosis group and the non cirrhosis group (all P<0.05). In the feasibility assessment of 2D-SWE technology, the success rate and stability of liver and spleen elastic operation were relatively high (success rate: 97.2% vs 81.3%; stability: 0.92 vs 0.84), and the success rate and stability of L-SWE operation were slightly better than S-SWE. The success rate of S-SWE operation in the cirrhosis group was higher than that in the non cirrhosis group ( P<0.05). The correlation analysis results showed that L-SWE, S-SWE, APRI were positively correlated with liver tissue pathological grading ( r=0.677, 0.528, 0.149, all P<0.05). The areas under the ROC curve for identifying liver cirrhosis using L-SWE, S-SWE, and APRI were 0.959, 0.896, and 0.706, respectively. When L-SWE and S-SWE were combined, the area under the ROC curve was 0.987, the sensitivity was 92.6%, and the specificity was 96.0%. The Delong test showed that the combined diagnosis of L-SWE and S-SWE had the same diagnostic efficacy as using L-SWE alone for liver cirrhosis ( P>0.05). Further analysis of the ROC curve showed that the likelihood of liver cirrhosis was low when L-SWE was less than 9.4 kPa, and high when L-SWE was greater than 12.0 kPa. Patients between 9.4 and 12.0 kPa can undergo further S-SWE testing; If the S-SWE was between 17.5 and 29.3 kPa, it was classified as 2D-SWE, which was difficult to determine whether there was liver cirrhosis, and further liver puncture and other examinations were needed. Conclusions:2D-SWE technology has high operational feasibility in the diagnosis of liver cirrhosis, and combined with S-SWE, it helps to improve the diagnostic efficiency of early non-invasive identification of liver cirrhosis, enabling more patients to avoid unnecessary liver puncture examinations.
6.Efficacy of color Doppler ultrasound-guided percutaneous nephrostomy in the treatment of anastomotic leakage after laparoscopic pyeloplasty in children
Xiangyang CHU ; Luping LI ; Junjie ZHANG ; Shengli ZHANG ; Xiaojiang HAN ; Xiang ZHAO ; Pengpeng LIU ; Bin YU ; Chunyu CHEN ; Yuchen LIU ; Nuoxian LI ; Yingzhong FAN
Chinese Journal of Urology 2024;45(8):587-591
Objective:To investigate the efficacy of color Doppler ultrasound-guided percutaneous nephrostomy in the treatment of anastomotic leakage after laparoscopic pyeloplasty.Methods:A retrospective analysis was performed for the data of 15 children with peritoneal irritation after LP who were admitted to the First Affiliated Hospital of Zhengzhou University from January 2018 to January 2023, of which 10 cases were anastomotic leaks and 5 cases were with renal pelvic blood clots. There were 12 males and 3 females. Age (4.2±2.7) years. The lesions were located on the left side of 11 cases and on the right side of 4 cases. All 15 cases had varying degrees of nausea, vomiting, abdominal pain and other symptoms. Physical examination: the children all showed painful faces and tense abdominal muscles. 15 patients had a preoperative pain score of 9.5 (8, 10). Ultrasound examination showed that the anterior and posterior diameters of renal pelvis separation were (34.93±4.86) mm, the anterior and posterior diameter/renal parenchymal thickness of renal pelvis separation was 15.66±1.02, renal dynamic nuclear imaging shows the renal function of the affected side was (29.69±1.71)%. Thirteen cases had the above symptoms before the abdominal drainage tube was removed, and the time of symptom onset was (3.3±1.1) days after surgery, of which 8 cases had a large increase in abdominal drainage, and color Doppler ultrasonography showed a large amount of fluid in the intra-abdominal intestinal space (about 500 ml). In 5 cases, the intraperitoneal drainage volume did not increase, and color Doppler ultrasonography showed strong echo in the renal pelvis, and blood clots were considered. All 13 patients were placed in the prone position under local anesthesia and underwent color Doppler ultrasound-guided percutaneous nephrostomy. The remaining 2 cases had abdominal drainage tube removed on the 3rd day after surgery, and peritoneal irritation signs appeared on the 4th and 6th days after surgery, respectively. Color Doppler ultrasonography showed that there was a large amount of fluid in the intra-abdominal intestinal space, and color Doppler ultrasound-guided peritoneal puncture and drainage + prone percutaneous nephrostomy was performed in the supine position under local anesthesia, and the biochemical analysis of the peritoneal puncture drainage fluid was confirmed to be anastomotic urine leakage. The drainage volume and urine output of 15 cases of peritoneal puncture drainage and pyelostomy were recorded, and the relief of nausea and vomiting symptoms and the score of postoperative pain after percutaneous nephrostomy were recorded. The changes of hydronephrosis and renal function before and after percutaneous nephrostomy were compared.Results:In this study, 15 patients underwent percutaneous nephrostomy with a duration of (16.8±1.9) min. The symptoms of nausea and vomiting disappeared after operation, and the pain scores were 3.2(2, 4) and 0.4(0, 2) at 2 h and 12 h after operation, respectively, which were statistically significant compared with those before operation ( P<0.01). In 13 children with simple percutaneous nephrostomy, the abdominal drainage tube was removed on (3.6±0.8) days and (8.6±1.0) days after percutaneous nephrostomy. In 2 children with peritoneal puncture and drainage plus percutaneous nephrostomy, the abdominal drainage tube was removed 3 days after the fistula operation, and the pyelostomy tube was removed 8 days after the fistula operation. The anterior and posterior diameters of renal pelvis separation were (10.87±4.05), (10.13±3.50) and (9.13±3.11) mm by color Doppler ultrasound at 3, 6 and 12 months after LP operation, respectively, and there were statistically significant differences compared with preoperative comparisons ( P<0.01).The diameter before and after renal pelvis separation was (7.60±2.86) mm, the diameter before and after renal pelvic separation/renal parenchymal thickness was 1.97±0.22, and the renal function was (39.23±2.66)% at 24 months after operation, which was statistically significant compared with that before operation ( P<0.01). Conclusions:Color Doppler ultrasound-guided percutaneous nephrostomy can effectively alleviate symptoms in the early stage, which could help to the healing of ureteral anastomosis, and has less trauma and short operation course.
7.The impact of central obesity on breast cancer risk and the significance of dietary factors
Yu ZHANG ; Chunwei LI ; Yongchao WANG ; Yuanyuan BAO ; Qi LI ; Lin LI ; Yi PANG ; Chunli GUO ; Yuchen FAN ; Xiangchao MENG ; Kang YU
Chinese Journal of Clinical Nutrition 2024;32(2):65-70
Objective:To explore the influence of central obesity on the risk of breast cancer and the possible role of dietary factors in its prevention.Methods:This study is a case-control study including a total of 212 participants, of whom 63 were with breast cancer, 71 were with breast nodules, and 80 were healthy controls. We used bioelectrical impedance analysis to measure body composition,and adopted the food frequency questionnaire to investigate dietary intake of participants.Results:The visceral adipose tissue ( OR=1.03, 95% CI: 1.003 to 1.077) and trunk fat mass ( OR=1.470, 95% CI: 1.104 to 2.184) were independently associated with the increased risk of breast cancer. Dietary patterns characterized by low dietary intake of beans and dairy products ( OR=1.300, 95% CI: 1.044 to 1.619) and high intake of cereals and red meat ( OR=2.254, 95% CI: 1.705 to 2.982) will increase the risk of breast cancer. Moreover, high meat intake ( β=0.268, 95% CI: 0.034 to 0.503) would advance the accumulation of visceral fat, while high bean intake ( β=-0.485, 95% CI: -0.865 to -0.104) would inhibit. Conclusions:Central obesity is an independent risk factor for breast cancer. Insufficient intake of beans and excessive intake of red meat are identified as factors that can exacerbate central obesity in breast cancer patients.
8.Expert consensus on safety management of inpatients with Alzheimer's disease
Yuchen QIAO ; Hong CHANG ; Hong SUN ; Kaiting FAN ; Xuan YANG ; Siying TIAN
Chinese Journal of Modern Nursing 2024;30(8):981-988
Objective:To develop an expert consensus on safety management of inpatients with Alzheimer's disease (AD) (referred to as the " Consensus") and standardize safety management strategies for AD inpatients. Methods:The evidence on safety management of AD inpatients was searched, evaluated, and summarized, with a search period from database establishment to July 31, 2023. This study conducted methodological quality evaluation and evidence extraction on the included article to form a consensus draft. A total of 24 experts from 15 hospitals across the country were selected for two rounds of Delphi expert consultation to analyze, revise, and improve their opinions, forming the final draft of the Consensus. Results:The positive coefficients for both rounds of expert consultation were 100.00% (24/24). In the second round of consultation, the expert judgment basis coefficient was 0.925, familiarity level was 0.846, authority coefficient was 0.886, Kendall harmony coefficient was 0.044 ( P<0.01). The Consensus elaborated on five common safety problems (loss, falling, aspiration/choking, self-injury/other injury, and medication errors in AD inpatients) from three aspects (assessment, identification of risk factors, and nursing strategies) . Conclusions:The Consensus is scientific and practical to a certain extent, providing guidance and reference for the safety management practice of AD inpatients.
9.Progress in the application of absolute ethanol in interventional embolization treatment of peripheral arteriovenous malformations
Qianyun HAN ; Yuchen SHEN ; Deming WANG ; Lixin SU ; Xiao LI ; Xindong FAN
Journal of Interventional Radiology 2024;33(11):1244-1252
Arteriovenous malformations(AVMs)are a kind of high-flow vascular malformation.AVMs can be classified in many ways,including histo-embryological classification,hemodynamic classification,etc.At present,the two mainstream classification systems used to guide the embolization treatment of peripheral AVMs are proposed by Cho and Yakes respectively based on the angiographic morphology of the lesions.Interventional embolization is the first-line treatment for AVMs.Among the many embolization agents,absolute ethanol is a permanent liquid embolization agent.Absolute ethanol can directly destroy the vascular endothelial cells to achieve a good curative efficacy,therefore,it has been wildly used in the treatment of peripheral AVMs.Yakes classification combines the angiographic classification with absolute ethanol embolization therapy.During absolute ethanol treatment,close attention should be paid to the occurrence of complications such as elevated pulmonary artery pressure.Although there are challenges remaining in the treatment of AVMs,the rapid development of molecular genetics has made targeted drug adjunctive treatment for AVMs possible.Perhaps,the novel therapeutic mode of combination use of traditional therapy targeted drug may be able to make a breakthrough in the treatment of AVMs.
10.Analysis of Serum Sestrin2 and TLR7 Level Expression in Patients with Severe Pneumonic Sepsis and Predictive Value for Heart Failure
Jian ZHANG ; Yuxing XU ; Yuchen LUO ; Qiqiang FAN ; Yang PANG ; Qingmei GONG
Journal of Modern Laboratory Medicine 2024;39(3):131-135,175
Objective To investigate the expression of serum Sestrin2 and Toll-like receptor 7(TLR7)in patients with severe pneumonia and sepsis and their predictive value for heart failure.Methods A total of 86 patients with severe pneumonia and sepsis complicated with heart failure(complicated with heart failure group)and 86 patients with severe pneumonia and sepsis(uncomplicated with heart failure group)who were diagnosed and treated in Shanxi Provincial People's Hospital from February 2022 to May 2023 were studied.Another 86 patients who underwent health examinations were included as the control group.Enzyme linked immunosorbent assay(ELISA)method was applied to measure serum levels of Sestrin2 and TLR7.Color doppler echocardiography was applied to measure cardiac function related indicators:left ventricular ejection fraction(LVEF),left ventricular end diastolic diameter(LVEDD),and left ventricular end systolic diameter(LESD).The expression of Sestrin2 and TLR7 levels and cardiac function in three groups was analyzed.Pearson correlation was applied to analyze the relationship between serum levels of Sestrin2 and TLR7 and cardiac function related indicators in patients with heart failure.Receiver operating characteristic(ROC)curve was applied to analyze the predictive value of serum levels of Sestrin2 and TLR7 in patients with severe pneumonia and sepsis complicated with heart failure.Results The serum levels of Sestrin2(11.59±3.31 ng/ml,16.13±3.62 ng/ml),TLR7(48.93±9.52 ng/ml,61.74±10.11 ng/ml),and cardiac function related indicators[LVEDD(53.28±5.76 mm,62.54±6.11 mm)and LESD(38.16±4.38 mm,48.15±5.02 mm)]were higher in uncomplicated heart failure group and complicated heart failure group than those in control group(7.11±2.34 ng/ml,40.12±10.16 ng/ml,44.86±5.02 mm,29.02±4.07 mm),with significant differences(qSestrin2=13.241,26.659,qTLR7=8.224,20.182,qLVEDD=13.824,29.028,qLESD=18.805,39.359,all P<0.05),and those values in complicated with heart failure group were higher than those in uncomplicated with heart failure group,with significant differences(q=13.418,11.985,15.203,20.554,all P<0.05).The LVEF(55.43%±6.62%,41.67%±5.84%)index in uncomplicated heart failure group and complicated heart failure group was lower than that in control group(62.75%±7.16%),with significant differences(q=10.344,29.789,all P<0.05),and the index in complicated with heart failure group was lower than that in uncomplicated with heart failure group,with significant difference(q=19.455,P<0.05).Pearson correlation analysis showed that serum levels of Sestrin2 and TLR7 in patients with heart failure were negatively correlated with LVEF(r=-0.419,-0.467,all P<0.05),and positively correlated with LVEDD and LESD(r=0.456,0.419;0.402,0.437,all P<0.05).Sestrin2 was positively correlated with TLR7(r=0.641,P<0.05).ROC curve results showed that the area under the curve(AUC)of serum Sestrin2 combined TLR7 for predicting heart failure in severe pneumonia sepsis patients was 0.940,with sensitivity of 74.9%and specificity of 73.3%.Conclusion The serum levels of Sestrin2 and TLR7 in patients with severe pneumonia and sepsis were elevated and may have good predictive value for patients with heart failure.

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