We conducted purification of filamentous temperature-sensitive protein Z of Streptococcus suis serotype 2 (S.suis 2) and measured its GTPase activity.The ftsz gene in the genome of the Chinese 05ZYH33 strain of S.suis 2 was successfully amplified using PCR,and then the ftsz gene was cloned into prokaryotic expression plasmid pET28a,and the recombinant plasmid pET28a-ftsz was transformed into E.coli BL21.After induction by IPTG,the isolated FtsZ protein was analyzed with SDS-PAGE.Then the recombinant protein was purified by Ni2+-NTA affinity chromatography.The rabbit serum was harvested after immunization with recombinant FtsZ protein,and was analyzed by indirect ELISA and Western blotting.The GTPase activity of FtsZ was measured with the malachite green method.Results showed that successfully constructed recombinant plasmid pET28a-ftsz and the recombinant protein with high purity was obtained;Western blot result indicated that FtsZ could react with the His-tag antibody and the rabbit serum;the polyclonal antibody titer of the rabbit serum reached 1 ∶ 13 107 200;FtsZ have GTPase activity.We successfully prepared S.suis 2 recombinant protein FtsZ having GTPase activity and high titer antiserum would be useful for the further study of S.suis 2 cell division mechanism.

Objective To investigate the clinical value of 64-slice spiral computed tomography(64-MSCT)triple-phase enhanced scan in diagnosis of lymphatic metastasis of gastric cancer.Methods Thirty patients with gastric cancer underwent plain and triple-phase enhanced scan by using 64-MSCT to analyze the relevant parameters of lymphatic metastasis.Results The four parameters de-termined metastatic perigastric lymph node as follows:①the short diameter ≥6 mm,②the ratio of short-to-long diameter ≥0.6,③the CT value in the portal venous phase≥ 65 HU,④the difference of CT values between portal venous phase and plain scan≥35 HU.The sensitivity and specificity of combining two parameters (①+②)in diagnosing metastatic lymph node were 90.5% and 29.0%,respectively.The sensitivity and specificity of combining three parameters (①+②+③)were 98.2% and 1 9.4%,respec-tively.The sensitivity and specificity of combining four parameters (①+②+③+④)were 99.7% and 13.2%,respectively.In ad-dition,metastatic lymph nodes were considered if they were ring-enhancement,or adhesions of several lymph nodes.Conclusion The use of 64-MSCT triple-phase enhanced scan and synthesis of various parameters of lymph nodes could lead to reliable diagnosis of lymphatic metastasis in gastric cancer with rapid,non-invasive,high sensitive and specific features.

Objective To investigate the expression and relationship of canonical transient receptor potential channel-3 (TRPC3) and brain-derived neurotrophic factor (BDNF) in the hippocampus of a rat model of Alzheimer's disease (AD). Methods SD rats were randomly divided into PBS, AD, and AD+BDNF experimental groups. AD models were generated by intracerebroventricular injection ofβ-amyloid protein (Aβ1-42). BDNF was injected via the lateral ventricle catheter after 14 days. The Morris water maze test was used to assess the spatial learning and memory ability of the rats. The expression of TRPC3 and BDNF mRNA and protein in the hippocampus were detected by RT-PCR and Western blotting, respectively. Results The Morris water maze test showed that the escape latencies of the fifth day in the AD group were longer than those in the PBS group (P ＜ 0. 05). The escape latencies in the AD+BDNF group were shorter than those in the AD group (P ＜ 0. 05). RT-PCR and Western blotting results showed that the expression of both TRPC3 and BDNF were reduced in the AD group compared with the PBS group (P ＜ 0. 05). TRPC3 expression was increased in the AD+BDNF group compared with the AD group (P ＜ 0. 05). Conclusion The expression of BDNF and TRPC3 is decreased in the hippocampus of AD rats. An exogenous BDNF injection appears to improve the spatial learning and memory of AD rats that are impaired by a Aβ1-42 injection, possibly via TRPC3 upregulation, and may play a protective role in neurons.

Objective To observe the changes of quadriceps tendon in type 2 diabetes mellitus(T2DM)patients based on ultrasonic elastography.Methods Data of 80 T2DM patients(T2DM group)and 80 healthy subjects(control group)were retrospectively analyzed.The general information and ultrasound elastography parameters,including strain ratio(SR)of the ratio of the proximal,middle and distal segments of quadriceps tendon and ipsilateral anterior femoral fat pad were compared between groups,while the correlations of the above SR with the disease course of T2DM and glycosylated hemoglobin(HbA1c)were explored.Results Fasting blood glucose and HbA1c in T2DM group were both significantly higher than those in control group(both P＜0.05).Compared with control group,SR of the proximal,middle and distal segments of quadriceps tendon in T2DM group were all significantly higher(all P＜0.05),especially the distal and proximal segments(t=6.01,5.92).In T2DM group,SR of the proximal,middle and distal segments of quadriceps tendon were positively correlated with the disease course of T2DM(r=0.45,0.20,0.43,all P＜0.05)and HbA1c(r=0.44,0.40,0.33,all P＜0.05).Conclusion SR of quadriceps tendon in T2DM patients significantly increased and positively correlated with the course of disease and HbA1c.

Objective To examine the safety, efficacy and durability of totally endoscopic minimally invasive (TEMI) mitral valve repair in Barlow’s disease (BD). Methods A retrospective study was performed on patients who underwent mitral valve repair for BD from January 2010 to June 2021 in the Guangdong Provincial People’s Hospital. The patients were divided into a MS group and a TEMI group according to the surgery approaches. A comparison of the clinical data between the two groups was conducted. Results A total of 196 patients were enrolled, including 133 males and 63 females aged (43.8±14.9) years. There were 103 patients in the MS group and 93 patients in the TEMI group. No hospital death was observed. There was a higher percentage of artificial chordae implantation in the TEMI group compared to the MS group (P=0.020), but there was no statistical difference between the two groups in the other repair techniques (P>0.05). Although the total operation time between the two groups was not statistically different (P=0.265), the TEMI group had longer cardiopulmonary bypass time (P<0.001) and aortic clamp time (P<0.001), and shorter mechanical ventilation time (P<0.001) and postoperative hospitalization time (P<0.001). No statistical difference between the two groups in the adverse perioperative complications (P>0.05). The follow-up rate was 94.2% (180/191) with a mean time of 0.2-12.4 (4.0±2.4) years. Two patients in the MS group died with non-cardiac reasons during the follow-up period. The 3-year, 5-year and 10-year overall survival rates of all patients were 100.0%, 99.2%, 99.2%, respectively. Compared with the MS group, there was no statistical difference in the survival rate, recurrence rate of mitral regurgitation, reoperation rate of mitral valve or adverse cardiovascular and cerebrovascular events in the TEMI group (P＞0.05). Conclusion TEMI approach is a safe, feasible and effective approach for BD with a satisfying long-term efficacy.

Objective To develop a novel transcatheter tricuspid valve replacement device and test its performance. Methods The transcatheter tricuspid valve stent consisted of double-layer self-expanding nitinol stent, biotissue-derived bovine pericardial leaflets, and PTFE woven. The delivery system, mainly consisting of a handle control unit and a delivery sheath, was sent to the correct position via right atrium or jugular vein. The sheath had a visualization feature, and the handle control unit could realize the functions of stable release and partial recovery of the interventional valve. In addition, this study performed animal survival experiments on the basis of in vitro experiments. A large-white pig was used as the experimental animal. Cardiopulmonary bypass was established through median thoracotomy, then the right atrium was opened, and the interventional valve was released under direct vision without cardiac arrest. Approximately 1 month after interventional valve implantation, the maneuverability and stability of the interventional tricuspid device were evaluated by autopsy. Results Through the animal experiment, the interventional valve was successfully released, and the anchoring was satisfactory. Postoperative transthoracic echocardiography showed that the interventional valve opened and closed well, the flow rate of tricuspid valve was 0.6 m/s, and there was no obvious tricuspid regurgitation. One month after the operation, we dissected the large-white pig and found the interventional valve was not deformed or displaced, the leaflets were well aligned, and there was thrombus attachment in the groove between the inner and outer layers of the interventional valve. Conclusion Animal experiment shows that the novel device can stably and firmly attach to the tricuspid annulus, with good anchoring effect, and effectively reduce paravalvular leakage.