Objective:To construct a recombinant bioluminescent bacteriophage (HT7) targeting Escherichia coli, and evaluate its ability to identify Escherichia coli. Methods:Initially, pCRISPR-sg (1-10) and PFN-1000 plasmid strains were constructed by genetic engineering, and the most efficient small guild RNA (sgRNA) were screened by bilayer plate. By the gene editing technique, which comprised homologous recombination and clustered regularly interspaced short palin dromic repeats (CRISPR)-Cas system, the Nanoluc luciferase gene was integrated into the downstream non-coding region of 10A gene of T7 phage, to constructe the bioluminescent phage HT7 successfully. The difference of biological characteristics between HT7 phage and T7 phage was evaluated by plaque assay and liquid amplification assay. In addition, 51 strains of Escherichia coli, 20 strains of Klebsiella pneumoniae, 14 strains of Staphylococcus aureus, 6 strains of Enterococcus faecium, 5 strains of Enterococcus faecalis, 3 strains of Acinetobacter baumannii and 1 strain of Pseudomonas aeruginosa were collected and isolated to evaluate the limit of detection and specificity of HT7 phage. Results:Among the 10 CRISPR-targeted cleavage systems constructed, sgRNA8 exhibited the highest cleavage efficiency, with a cleavage rate of 0.18. After three rounds of recombination screening using the pCas9/pCRISPR/PFN-1000 triple-plasmid system, PCR validation yielded recombinant phage bands at 2 798 bp, indicating the successful construction of the HT7 phage. The recombinant phage showed significant differences in biological characteristics in terms of lysis efficiency ( P<0.001), one-step growth curve ( P=0.001), and infection multiplicity ( P=0.031). Both lysis burst time and log growth node were extended by 10 min, with the optimal infection multiplicity being 0.1. Clinical sample testing identified lysis of 6 strains of Escherichia coli within 4.5 h, while other strains remained unaffected, with detection of pathogenic bacteria below 10 CFU/ml. Conclusions:The developed pCas9/pCRISPR/PFN-1000 triple-plasmid editing system efficiently edits the bacteriophage genome. The constructed HT7 fluorescent bacteriophage enables the detection of Escherichia coli below 10 CFU/ml within 4.5 hours, demonstrating low detection limits and high detection specificity.

OBJECTIVE: To evaluate the diagnostic ability of toxicity pathology in patho-toxicological testing institutions in China. METHODS: The institutions participated in the 2018 Interlaboratory Comparison Activity of Toxicity Pathology Testing(hereinafter referred to as reference unit) were selected as the research subjects. The heart, spleen, skin, soft tissue, liver and mammary gland of SD rats of different groups in the 2-year carcinogenesis test were selected. The femur, knee joint and nose of Beagle dogs in the 4-week toxicity test and a total of 10 pathological tissues were selected as the comparison samples. The pathological diagnosis was carried out by the pathological diagnostic personnel of the reference unit, and the diagnostic results were reported. The expert appointed by the Toxicology and Pathology Committee of Chinese Toxicology Association compared the diagnostic results with the appointed value. RESULTS: A total of 167 pathological diagnostic personnel from 75 reference units in 24 provinces and municipalities participated in the comparison activity. The reference units were mainly distributed in East China, South China and North China, accounting for 77.3%(58/75). Totally 75 reference units fed back 750 effective diagnostic results. The qualified rates of diagnosis on heart, spleen, skin, soft tissue and breast samples were higher than 60.0%. The qualified rates of diagnosis on femur and knee joint, and nose samples were low(30.7% and 6.7%, respectively). There were 1(1.3%), 46(61.4%) and 28(37.3%) reference units rated as unqualified, qualified and excellent, respectively. CONCLUSION: Most of the testing institutions in China have a high level of patho-toxicological diagnostic ability, that can provide reliable diagnostic results for toxicology safety evaluation tests.

Objective To investigate the effects of hydrogen (H2) on myocardium injury post-cardiac arrest (CA) in rabbits.Methods Sixty New Zealand rabbits were randomly divided into H2 treatment group (n = 30) and control group (n = 30) by random number table. The rabbit CA model was established by means of electrical stimulation of external membrane, both groups were mechanically ventilated. Cardiopulmonary resuscitation (CPR) was performed after 6 minutes of nonintervention, and stopped after restoration of spontaneous circulation (ROSC). Inhalation of 2％ H2 gas was conferred to rabbits immediately at the end of CA modeling for 72 hours in H2 treatment group. Air was given to rabbits in control group instead. The survival rate of rabbits was analyzed. Heart rate, ventricular premature beat frequency, and the levels of blood samples cardiac troponin I (cTnI), left ventricular ejection fraction (LVEF), B-type natriuretic peptide (BNP), and blood lactic acid (Lac) were collected before CA and after ROSC in all rabbits. Rabbits were sacrificed and microstructure injury was observed by electric microscope after ROSC 72 hours.Results There were 28 animals ROSC in both groups; the survival number in H2 treatment group was higher than that in control group at 72 hours after ROSC (number: 15 vs. 7,χ2 = 4.791,P = 0.029). In the early stage of ROSC, the heart rate of two groups slowed down, the number of premature ventricular increased, and then gradually recovered; the heart rate in H2 treatment group was returning to normal more quickly than that in control group at 48 hours after ROSC (bpm: 319±63 vs. 362±40,P < 0.05); the ventricular premature beat frequency was lower than that in control group at 72 hours after ROSC (times per minutes: 9.1±4.3 vs. 15.0±8.0,P < 0.05). The animals of two groups had different degrees of myocardial damage and cardiac insufficiency after ROSC, and restored with the extension of time. Compared with control group, the level of BNP in H2 treatment group was significant decreased at 24 hours after ROSC (ng/L: 385±98 vs. 488±174,P < 0.05), the levels of cTnI and Lac were significant decreased at 48 hours after ROSC [cTnI (μg/L:1.83±0.68 vs. 2.83±0.98, Lac (mmol/L): 5.5±1.6 vs. 7.9±2.6, bothP < 0.01], the LVEF was slightly higher than that at 72 hours after ROSC (0.690±0.040 vs. 0.650±0.041,P = 0.051). Compared with control group, less damage to myocardial ultra structure was found in H2 treatment group at 72 hours after ROSC.Conclusion Inhalation of H2 alleviates cardiac dysfunction and myocardial injury after CPR.

The continuing education system at the Peking University Health Science Center for vis-iting scholars (Research program for young and middle-aged doctors) is a relatively advanced and compre-hensive medical continuing education system in China, among which, the tutorial system is a good method to guide the visiting scholars of continuing education. On this basis we conducted scholars learning effect questionnaire survey and combined with the feedback results, discussed the advantages and disadvantages of the current educational system of visiting scholars in China, and put forward some concrete suggestions on the development of the continuing education in China.

Objective:To compare the pain control efficiency of continuous adductor canal block (ACB) and femoral nerve block (FNB) in total knee arthroplasty.Methods:From April to September 2016,patients with severe knee osteoarthritis undergoing primary unilateral total knee arthroplasty (TKA) were prospectively observed,and all the patients were randomized received ultrasound-guided continuous ACB or FNB after surgery.Numeric pain rating scales (NPRS)pain scores in rest and activity 2,6,12,24 and 48 h after surgery were collected,and the preoperative and postoperative quadriceps strength at 24 and 48 h were analyzed.Opioids consumption and anesthesia related adverse effects were also recorded.Results:In the study,40 patients were enrolled,with 20 patients in each group,male ∶female =7 ∶ 33,the age:(63.8 ± 10.1) years,and the body mass index (BMI):(28.5 ± 3.5) kg/ m2.The general conditions were comparable between the two groups.Though the rest pain 2 h after surgery [ACB =0.0(0,6),FNB =3.0(0,5),P=0.004] and activity pain 12 h post operation [ACB =3.0(3,0),FNB =5.5(0,10),P =0.004] were lower in ACB group compared with FNB group,there was no statistical difference in the other pain checking points between the two groups.The quadriceps strength 24 h and 48 h after surgery were (85.3-± 27.6) N and (80.0 ± 30.1) N in ACB group,(69.0 ± 29.4) N and (64.4 ± 32.0) N in FNB group,both of them were declined by time.The exact data were higher in ACB group,however,there was no statistical difference between the two group by repeated measurements variance analysis(F =2.703,P =0.108).Four patients in ACB group and five in FNB acquired additional use of dolantin once (100 mg/per time) within 24 h.And among them,three patients acquired once dolantin in ACB,two in FNB,from 24 to 48 h postoperation.There were five patients who suffered nausea postoperation in ACB group,and one who reported xerostomia.Four patients in FNB had nausea with vomiting,and three experienced xerostomia.Deep vein thrombosis appeared in 2 patients in FNB group,but no one in ACB group.Conclusion:Continuous ACB is not superior in pain control after TKA compared with FNB,and the quadriceps strength could be reserved more by this method,which performed early benefits in fast rehabilitation.

Toxascaris leonina is a common parasitic nematode of wild mammals and has significant impacts on the protection of rare wild animals. To analyze population genetic characteristics of T. leonina from South China tiger, its mitochondrial (mt) genome was sequenced. Its complete circular mt genome was 14,277 bp in length, including 12 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 2 non-coding regions. The nucleotide composition was biased toward A and T. The most common start codon and stop codon were TTG and TAG, and 4 genes ended with an incomplete stop codon. There were 13 intergenic regions ranging 1 to 10 bp in size. Phylogenetically, T. leonina from a South China tiger was close to canine T. leonina. This study reports for the first time a complete mt genome sequence of T. leonina from the South China tiger, and provides a scientific basis for studying the genetic diversity of nematodes between different hosts.
Animals ; Animals, Wild ; Bias (Epidemiology) ; China* ; Codon, Initiator ; Codon, Terminator ; DNA, Intergenic ; Genes, rRNA ; Genetic Variation ; Genome ; Genome, Mitochondrial* ; Mammals ; Phylogeny ; RNA, Transfer ; Sequence Analysis* ; Tigers* ; Toxascaris*

It is very frequent that patients undergoing total knee arthroplasty ( TKA) suffer a severe pain from the bone cutting and soft tissue balance procedures postoperatively .In addition , pain control is the key point of the rehabilitation after surgery . Therefore, establishing an effective method to decrease the pain should be considered as a priority .Femoral nerve block (FNB), as a common and effective peripheral nerve block after TKA , affects the strength of quadriceps femoris and the postoperative recovery . Adductor canal block (ACB), targeting at the saphenous nerve , is proved to be as effective as FNB in pain control , and has less influence on the quadriceps strength .However , considering about the short time following up , the expansion of local anesthesia drug and few reports in China , the application of ACB in TKA needs further study .

Objective To summarize the experiences of diagnosis and treatment for blunt tracheobronchial injuries ( BTI) . Methods From January 1993 to December 2013, 15 patients were diagnosed with BTI and underwent surgical treatment at our hospital.Mean age of the 15 patients (11 men and 4 women) was 26.4 ±4.5 years.All the patients had a history of trauma, which included crushing injury in 8 cases, deceleration injury in 4, fall injury in 2, and traction-type injury in 1.BTI loca-tion: right main bronchus in eight cases, left main bronchus in four cases, upper trachea in one case, lower trachea with the right main bronchus in one case, and cervico-thoracic trachea with left main bronchus in one case .Thoracic computerized tomo-graphy was performed in 15 patients, which showed pneumothorax, subcutaneous emphysema, pneumomediastinum or falling lung sign of Kumpe.Preoperative fiberoptic bronchoscopy examination was performed in 15 cases, which included bronchial atresia in 9 cases, bronchial transection in 3 cases, laceration of trachea in 2 cases, and tracheal transection in 1 case.An e-lective surgical procedure after BTI was performed in 10 cases, and emergency surgery was performed in 5 cases.Tracheo-bron-chial laceration repair were performed in 2 cases, tracheal end-to-end reanastomosis in 1 case, and bronchial end-to-end re-anastomosis in 12 cases.Results There was no operative death, and one case was complicated with anastomotic stenosis.The average operation time was 205.7 ±41.3 minutes, and the average blood loss was 268.4 ±109 ml.The postoperative hospi-tal stay was 11.6 ±3.7 days on average.Follow-up was completed in 15 patients (mean, 29.3 months), and 15 patients were all symptomatic improvement .Conclusion The most common site of BTI was the right main bronchus near Carina parts .Al-though the diagnosis and treatment are often delayed , our findings indicate that chest CT and endoscopic findings could be used for the diagnosis of BTI.Surgical resection and reconstruction are effective methods to repair BTI successfully even many months after they occur.Often they do not require the resection of pulmonary parenchyma .

Objective To explore the expression characteristic of T regulatory cell (Treg)/T help cell (Th)17 and the correlation to disease progression in chronic hepatitis B (CHB) patients undergoing antivirus treatment,and to explore their roles in pathogenesis of CHB.Methods A total of 53 patients with CHB (CHB group) and 21 healthy controls (healthy control group) were selected,CHB patients included mild 18 cases,moderate 16 cases and severe 19 cases.The expression of Treg and Th17 were detected by flow cytometry and compared.The levels of alanine aminotransferase (ALT),total bilirubin (TBIL),cholinesterase,albumin were measured by automatic biochemical machine and for correlation analysis.Results The levels ofTh17,Treg,Treg/Th17 were (2.13 ± 0.65)％,(2.99 ± 0.68)％ and (6.07 ± 1.18)％,(5.14 ± 0.96)％ and 2.86 ± 0.67,1.73 ± 0.45 in CHB group before and after treatment for 24 weeks and (3.59 ± 0.75)％,(4.02 ± 0.77)％,1.04 ± 0.34 in healthy control group.There were significant differences (F =14.78,10.12,17.19; P ＜ 0.01).The level of Th17 in mild,moderate and severe CHB was gradually decreased,but there was no significant difference (F =1.10,P =0.337).The level of Treg in mild,moderate and severe CHB patients was gradually increased,but there was no significant difference (F =0.54,P =0.585).The level of Treg/Th17 was gradually increased with aggravation (2.58 ± 0.59,2.76 ± 0.63,3.21 ± 0.71),and there was significant difference (F =3.15,P ＜ 0.01),the level of Treg/Th17 in severe CHB patients was significantly higher than that in mild,moderate CHB patients (P ＜0.05).The level of Treg/Th17 had significantly positive correlation with ALT,TBIL (r =0.272,P=0.000; r =0.226,P=0.000).Conclusion Treg/Th17 balance not only relates with the pathogenesis of CHB,but also with the related immune inflammatory of liver tissue.

Objective To assess metabolic state in patients with Roux-y sigmoid neobladder.Methods The study comprised 33 patients(21 men and 12 women) with Roux-y sigmoid neobladder after oneological sur-gery.All enrolled patients were treated by the same protocol.Before and after withdrawing the catheter , serum e-lectrolytes, ereatinine and urea were analysed and used to assess the effect.Results All 33 patients were evalu-able.Before and after withdrawing the catheter , serum electrolytes, creatinine and urea were normal values and there was no signifcant difference(P >0.05).Three patients developed mild metabolic acidosis.Conclusions The Roux-y sigmoid neobladder is a feasible , safe and effective method for continent urinary diversion.This surgi-cal technique had no signifcant effect on metabolic state.