To investigate the clinical efficacy of extended thymectomy by subxiphoid approach video-assisted thoracoscopic surgery(VATS) for myasthenia gravis. Methods We retrospectively analyzed the clinical date of 64 cases of myasthenia gravis treated by subxiphoid approach VATS in the same surgical team from September 2015 to April 2018. The patients were equally divided into 4 groups(A, B, C and D) according to the date of operation. Comparisons were made among the four groups in operation time, blood loss during operation, rate of conversion to thoracotomy, postoperative complications, postoperative hospital stay, duration and amount of postoperative chest tube drainage, frequenlly of surgery. The operative effect of different stage was analyzed. Results There were no intraoperative deaths. 1 patient(group A) was converted to thoracotomy. 3 patients(2 cases of group A; 1 case of group D) had lung infection. 1 patient(group B) developed myasthenia crisis after surgery, and the rest patients showed obvious improvement in postoperative myasthenia symptoms. No significant differences were found in postoperative complications, rate of conversion to thoracotomy, postoperative hospital stay, duration and amount of postoperative chest tube drainage among the 4 groups(P >0. 05). The operation time was significantly longer in group A(186. 25 ± 25. 79) min than the other 3 groups [B(128. 75 ± 16. 28) min, C(135. 00 ± 21. 29) min, D(128. 75 ± 19. 62)min], P <0. 05. The blood loss in surgery was significsntly more in group A(110. 00 ±38. 82)ml than that in the other 3 groups[B(63. 75 ±28. 26)ml, C(58. 13 ±27. 86)ml, D(58. 75 ±25. 00)ml], P <0. 05, while no statistical difference was found among group B, C and D. The frequency of surgery was increased from 1. 6 cases in group A to 2. 3, 2. 7 and 2. 7 cases one month in B, C and D, respectively. Conclusion The results of the present study have shown that subxiphoid approach VATS thymectomy is safe and feasible for the treatment of MG patients. For thoracic surgeons with certain experience in thoracoscopic technique, a plateau of the surgical skill of the subxiphoid opproach can be reached after learning curve procedures.

Objective:To summarize the surgical treatment experience of extended thymectomy for myasthenia gravis(MG), and to explore the surgical treatment of MG.Methods:Retrospectively analyzed the clinical data of 527 MG patients undergoing extended thymectomy in our hospital from June 1996 to October 2017, including 242 males and 285 females, aged 5 to 77 years, with a mean age of(52.6±13.7) years old. The course of illness was 12 days to 18 years. There were 22 cases of hyperthyroidism, 7 cases of pure red blood cell aplastic anemia, 1 case each of hypothyroidism, irritable bowel disease, rheumatoid arthritis, ankylosing spondylitis and thrombocytopenia syndrome. There were 272 cases of MG in Osserman Ⅰ, 72 cases inⅡa, 78 cases inⅡb, 81 cases in Ⅲ, and 24 cases in Ⅳ, respectively. The muscle fatigue test and neostigmine test of all patients were positive, and the diagnosis was confirmed by chest CT examination. Meanwhile, summarize the perioperative data and postoperative follow-up.Results:3 cases died during the postoperative period, all of which were thymoma with MG, including 2 cases of Osserman Ⅲ MG and 1 case of Ⅳ MG; 15 cases of postoperative myasthenia crisis, including 2 OssermanⅡb cases, 11 Osserman Ⅲ cases and 2 Osserman Ⅳ cases, also including 7 cases of tracheotomy; 70 cases of plasma exchange, of whom 2 cases of hypotonic syndrome and 2 cases of lower extremity venous thrombosis. The postoperative pathological types were followed by thymic hyperplasia 293 cases(55.60%), thymoma 207 cases(39.28%), thymic cyst 24 cases(4.55%) and thymic atrophy 3 cases(0.57%) in descending order. 378 cases were followed up with an average follow-up of(85.9±58.5)months; MG with complete remission, partial remission, no change and deterioration accounted for 135(35.71%), 192(50.79%), 41(10.85%) and 10(2.65%)cases, respectively. Complete remission rate ranked as Osserman typeⅠ>Ⅱa>Ⅳ>Ⅱb>Ⅲ, the deterioration rate from high to low was Osserman type Ⅲ>Ⅳ>Ⅰ. 18 OssermanⅠcases showed no effects, whose preoperative course of disease> 5-10 years; 1 OssermanⅠcase was worsening who initially was diagnosed with ophthalmic MG and underwent video-assisted thoracoscopic thymectomy. The left thymus lobe was left unresected and developed 6 years later. Another operation was performed to remove the left lobe thymus, confirming the compensatory hypertrophy of the left lobe thymus. Among the worsening patients, 6 died, all of them were thymoma with MG, including 5 cases of type Ⅲ and one case of type Ⅳ. The cause of death was omyasthenia crisis(3 cases), sudden respiratory arrest after 3 months of rapid stopping of brompistigmine(2 cases)and cholinergic crisis(1 case).Conclusion:Standardized extended thymectomy is an effective method for the treatment of MG. Earlier surgery for ocular muscle type MG can effectively reduce the risk of generalization. MG with Osserman Ⅱb or higher is prone to myasthenia crisis. Comprehensive treatments should be taken to reduce MG-related risks. Myasthenia crisis can occur repeatedly in severe patients in the long term after surgery, requiring regular medication and comprehensive MG treatments.

Objective: The aim of this study is to investigate the effect of G9a inhibitor BIX-01294 on attenuating cell proliferation in human lung adenocarcinoma A549 cell line and the underlying molecular mechanism. Methods: Treated with BIX-01294, the growth and proliferation of A549 cells were detected by MTT assay and colony formation assay, and its impact on cell apoptosis was analyzed using flow cytometry. By Western blot, we explored the alterations in the expression of apoptosis-related proteins and the G9a catalysate, H3K9me and H3K9me2. In addition, in the pretreatment with caspase inhibitor Z-VAD-FMK, we detected the apoptotic dependence of BIX-01294 attenuating impact on A549 cell proliferation. Results: Compared with the control group, the histone methyltransferase G9a inhibitor BIX-01294 attenuated cell proliferation in A549 cells in a dose- and time-dependent manner. There were 42.5±8.7 colonies after BIX-01294 (10 μmol/L) treatment for 7 days, while 172.7±23.0 colonies in the control group, with a statistical significance (P<0.05). After treatment with BIX-01294 (10 μmol/L) for 24 hours, the cell apoptotic rate was(47.6±8.4)%, with a significant difference in comparison with the control group [(7.2±3.6)%, P<0.05]. The expression of G9a catalysate, H3K9me and H3K9me2 was downregulated, the same with anti-apoptotic protein Bcl-2, while the proteins in mitochondrial apoptosis pathway, Bax, Bak and cleaved caspase-9, were upregulated, so was the expression of cleaved caspase-3 and cleaved PARP, and there was no alteration in the expression of cleaved caspase-8, which is a protein related with death receptor apoptosis pathway. Furthermore, after Z-VAD-FMK pretreatment, the cell apoptotic rate was decreased significantly, and the expression of apoptosis-related proteins were downregulated. Conclusions Our results indicate that BIX-01294 can attenuate cell proliferation in lung adenocarcinoma, and it can be considered as one of the underlying mechanisms, the apoptosis may be induced by activating mitochondrial pathway.