Left atrial enlargement is an independent risk factor for ischemic stroke and other cardiovascular adverse events. It can affect stroke severity and increase the risk of recurrence. The mechanisms associated with left atrial enlargement and ischemic stroke are not yet clear. It may be associated with atrial thrombosis or co-morbidity, such as atrial fibrillation and hypertension. How to conduct primary and secondary prevention of stroke patients with left atrial enlargement still need further clinical trials to determine.

Objective To investigate the associations of left atrial enlargement and the severity and lesion patterns of cardioembolic stroke in patients with nonvalvular atrial fibrillation (NVAF).Methods The patients with NVAF diagnosed as cardiogenic stroke within 48 h after onset were enrolled.The National Institutes of Health Stroke Scale (NIHSS) was used to evaluate the severity of stroke,and ≥ 10 was defined as moderate to severe stroke,and ＜ 10 was defined as mild stroke.Transthoracic echocardiography was used to measure the left atrial diameter.The patients were divided into normal group,mild,moderate,and severe left atrial enlargement groups.According to the lesion patterns revealed by the diffusion weighted imaging,they were divided into either a multiple infarctions group or a single infarction group.Results A total of 137 patients were enrolled,including 86 patients with mild stroke (62.8％),51 with moderate to severe stroke (37.2％),69 with multiple infarctions,and 68 with single infarction (49.6％).Left atrial enlargement was found in 103 cases,in which 35 (25.5％) were mild enlargement,40 (29.2％) were moderate enlargement,and 28 (20.4％) were severe enlargement.Multivariate logistic regression analysis showed that the risk of severe stroke in patients with mild (odds ratio [OR] 15.662,95％ confidence interval [CI] 1.821-134.677;P =0.012),moderate (OR 26.435,95％ CI 3.201-218.319;P =0.002),and severe (OR 75.763,95％ CI 8.536-672.441;P＜0.001) left atrial enlargement were increased significantly,and there were no significant differences in the lesion patterns among the different severity of left atrial enlargement groups (x2 =7.050,P =0.07).Conclusions Left atrial enlargement may be independently associated with the severity of cardiogenic stroke in patients with NVAF,but it is not associated with the lesion patterns.

Nobel Prize 2009 in Physiology or Medicine is awarded to three American scientists, Elizabeth H.Blackburn, Carol W.Greider and Jack W.Szostak, for the discovery of"how the chromosomes are protected by telomeres and the enzyme telomerase".Telomere is the specific structure at the ends of the chromosomes and protects it from fusion and degradation.Telomerase synthesizes telomere DNA to maintain the telomere length.Studies suggest that telomere length and telomerase activity is directly associated with cell life and the genesis of many diseases.With the progress of study, how to control the telomere length and telomerase activity is helpful to shed light on the studies in"cancer, inherited diseases and senescence", and will stimulate the development of potential new therapies.

E.coli single-stranded DNA-binding protein (SSB) plays an important role in replication, recombination and repair of DNA and is thus crucial for the survival of the bacteria.We described a high expression and efficient purification scheme and kinetic assay of interaction with its substrate, single-stranded DNA (ssDNA). A ssb gene (537 bp) for encoding SSB was obtained by PCR amplification from E.coli K-12 genome. The expression vector of the fusion protein SSB was constructed by attaching ssb gene to pQE30. SSB fusion protein was expressed in M15 E.coli strain induced by IPTG. SDS-PAGE analysis revealed that the expected protein with a molecular weight 20.6kDa was soluble and amounted to about 30% of the total bacterial protein. SSB protein was purified by immobilized metal (Ni2+) chelation affinity chromatography and the purity was about 90%. The resulting SSB protein was a correctly folded tetramer analyzed by gel filtration. It could bind ssDNA with equilibrium dissociation constant (KD) of 4.79×10-7 mol/L as determined by surface plasmon resonance.

MutL and MutS or their homologues are two crucial proteins of DNA mismatch repair (MMR) system. A new method was described for observation of the interaction between MutS and MutL which is based on the fusion gene/fusion protein technique. Three fusion proteins, MutL-GFP fusion (Trx-His6-GFP-(Ser-Gly)6-MutL), MutL-Strep tag Ⅱ fusion (Trx-His6-(Ser-Gly)6-Strep tagⅡ-(Ser-Gly)6-MutL) and MutS fusion (Trx-His6-(Ser-Gly)6-MutS), were constructed and expressed in E. coli AD494 (DE3). Interaction assay between MutS and MutL was performed in a 96-well microtiter plate.MutS fusion protein was immobilized on the wells and provided a surface for the interaction between MutS and MutL.Results showed that only after binding of MutS to the mismatched DNA, there was an interaction between MutS and MutL.The binding events could be indicated by GFP signal or the signal generated from alkaline phosphatase and its substrate. In addition, the method based on fusion molecular system also serve as a model for studies on the interactions among other proteins or biomolecules.

Objective A preliminary study on a new discovered proteomic fingerprint correlated with anxiety disorders, which M/Z range from 15000 to 16800. Methods 221 cases of neoplasm patients from April of 2004 to now were divided into anxious group and non-anxious group according to their scores using self-rating anxiety scale (SAS), and all the patients' sera were detected utilizing SELDI-TOF-MS. The data were analyzed with supported softwares. Results Compared the mass spectra of anxious group(n=49) and non-anxious group (n=172), 2 clusters were captured which M/Z range from 15 000 to 15 380 and 15 700 to 16 800 respectively. The coincidence with SAS was 75.51%. The M/Z range from 15 700 to 16 800 was the most frequent, then the second range from 15 000 to 15 380 and 15 700 to 16 800 which was doublet cluster, the least range from 15 000 to 15 380. The same fingerprints were captured in non-anxious group and their intensity was different. Conclusion The M/Z range from 15 000 to 16 800 was protein fingerprint correlated with anxiety disorders.

Objective To compare the efficacy of laparoscopic and conventional open total mesorectal excision (TME) in the treatment of rectal cancer, and to explore the considerations of laparoscopic TME. Methods 75 cases of laparoscopic group and 61 cases of open surgery group were analyzed retrospectively, and cohort study was used to compare the perioperative indicators and clinicopathological results in the two groups. Results Between the laparoscopic group and the open surgery group, the operative incision [8.7 cm (8.0-10.0 cm) vs. 13.6 cm (10.0-16.0 cm)], the use of postoperative analgesics (8 cases vs. 23 cases), postoperative time to remove the drainage tube [5 d (5-6 d) vs. 6 d (6-8 d)], postoperative time to get out of bed [3 d (3-7 d) vs. 5 d (4-8 d)] and postoperative hospital stay time [6 d (5-18 d) vs. 8 d (6-25 d)] had statistical difference (all P<0.05). The cost of laparoscopic group was higher than that of open surgery group (each patient in laparoscopic group spent more about 7 000 yuan than ones in open surgery group ). There was a significant difference in the overall complication rate between the laparoscopic group and the open surgery group [6.7 % (5/75) vs. 13.1 % (8/61), P<0.05]. Conclusions The postoperative analgesics, removal of drainage tube time, hospital stay and other indicators in the laparoscopic TME are superior compared with those in the open surgery, but due to the use of high-value consumables, the cost of laparoscopic surgery is higher. Besides, laparoscopic resection of rectal cancer should be careful.

Objective:To discuss the procedure for correction of inverted nipple using tiny incision with primary breast ducts reserved.Methods:A total of 35 patients (63 sides) with primary inverted nipples from January 2006 to March 2019 were reviewed retrospectively. Tiny radial incisions were made on the areola around the base of the inverted nipple which had been pulled out. Without skin removed, shorten fiber bundles which caused nipple inverted were totally cut and released. While the primary breast ducts were preserved, purse-string suture was taken around the base of the nipple. The nipple protector was prepared by ourselves, and the nipple was pulled and suspended for 2-6 months.Results:Sixty-three sides of 35 patients with inverted nipples were successfully corrected by this minimally invasive surgery. There was no nipple necrosis. One patient developed mild swelling 3 weeks after operation, and the swelling subsided after symptomatic anti-inflammatory treatment. The average follow-up period was 39 months. After removing the nipple protector, 2 sides (2/63) had a certain degree of recurrence. The rest of the nipples had ideal shape, no obvious scar, good nipple feeling, and retained the possibility of lactation.Conclusions:The procedure for correction of inverted nipple using tiny incision with primary breast ducts reserved has advantages of minimal invasion, safety, less pain, while retaining the possibility of lactation in the future. The clinical effect is satisfactory. It is especially suitable for the correction of type Ⅰ and type Ⅱ inverted nipples.

This research aims at the existing problems of medical students' information literacy to cultivate medical students' information literacy through the construction of cloud libraries, medical school characteristic library, medical schools sharing electronic resources and the establishment of medical student information literacy competitions. The results show that the total scores of medical students' information awareness, information knowledge, information ability, information ethics and information literacy have been greatly improved after the teaching reform [(11.56±1.37) vs. (15.64±1.88), (10.28±1.33) vs. (16.50±1.64), (9.50±1.29) vs. (15.22±1.90), (10.04±1.23) vs. (14.81±1.57), (41.92±3.20) vs. (61.59±3.57)], with statistical significance ( P<0.001). The medical significance shows that the teaching reform based on the construction of the library's diversified information source system can significantly improve the information literacy level of medical students.

Objective:To analyze the characteristics of drug resistance genes in a Klebsiella pneumoniae strain coproducing carbapenemases KPC-2 and NDM-5. Methods:Klebsiella pneumoniae KPN-hnqyy was separated from the stool specimen of a patient in the Hematology Department of Affiliated Cancer Hospital of Zhengzhou University. The strain was identified with a BD Phenix-M50 automated microbiology system and the minimum inhibitory concentration against the strain was measured as well. The genotypes of the carbapenemases were tested by enzyme immunochromatographic assay and PCR method. The transferability of related plasmids was analyzed by conjugation test. Whole-genome sequencing of the strain was conducted using PacBio and Illumina platforms. The MLST type, resistance gene and plasmid type of the strain were retrieved in BacWGSTdb. The genome and open reading frame sequence of the strain were compared using Easyfig_2.2.3. Visual cycle graphs were generated using BRIG v0.95. Results:Klebsiella pneumoniae KPN-hnqyy was resistant to carbapenem antibiotics. It belonged to ST11 and carried two carbapenemase genes of blaKPC-2 and blaNDM-5. The conjugant only harbored the blaKPC-2 gene. Whole-genome sequencing revealed that the strain contained one chromosome and three plasmids. Its chromosome genome shared more than 99.9% similarity with that of Klebsiella pneumonia KP69 and KP19-2029. Moreover, a similar IncR and IncFⅠ resistance gene fusion region was contained in different types of plasmids carried by them: the blaKPC-2 gene was located in a structure—which evolved from the Tn3-△Tn4401-Tn1721/Tn1722 sequence—inside this fusion region with its ends inserted into the transposase IS26 gene; the blaNDM-5 gene was located on a transposon containing the special plasmids of the insertion fragment in phages, with its ends inserted into the transposase IS26 gene too. Conclusions:The IncR and IncFⅡ resistance gene fusion region of blaKPC-2 carried by Klebsiella pneumoniae ST11 might be widely coexistent with the chromosomal genome. The blaNDM-5 gene carried by special plasmids might be accidentally obtained through gene recombination mediated by transposable element IS26. The wide transmission of Klebsiella pneumoniae ST11 carrying the blaKPC-2 gene in China and its ability to obtain other carbapenemase genes through transposable element IS26 were well worth attention.