Real-Time Detection Reveals Responsive Cotranscriptional Formation of Persistent Intramolecular DNA and Intermolecular DNA:RNA Hybrid G-Quadruplexes Stabilized by R-Loop.

G-quadruplex (GQ) structures are implicated in important physiological and pathological processes. Millions of GQ-forming motifs are enriched near transcription start sites (TSSs) of animal genes. Transcription can induce the formation of GQs, which in turn regulate transcription. The kinetics of the formation and persistence of GQs in transcription is crucial for the role they play but has not yet been explored. We established a method based on the fluorescence resonance energy transfer (FRET) technique to monitor in real-time the cotranscriptional formation and post-transcriptional persistence of GQs in DNA. Using a T7 transcription model, we demonstrate that a representative intramolecular DNA GQ and DNA:RNA hybrid GQ promptly form in proportion to transcription activity and, once formed, are maintained for hours or longer at physiological temperature even after transcription is stopped. Both their formation and persistence strongly depend on R-loop, a DNA:RNA hybrid duplex formed during transcription. Enzymatic removal of R-loop dramatically slows their formation and accelerates their unfolding. These results suggest that a transcription event is promptly read-out by GQ-forming motifs and the GQ formed can either perform regulation in fast response to transcription and/or memorized in DNA to mediate time-delayed regulation under the control of RNA metabolism and GQ-resolving activity. Alternatively, GQs need to be timely resolved to warrant success of translocating activities such as replication. The kinetic characteristics of GQs and its connection with the R-loop may have implications in transcription regulation, signal transduction, G-quadruplex processing, and genome stability.

[Comparison of Southern blotting and Real-time PCR in measuring telomere shortening].

OBJECTIVE: To analyze and compare the performances of two telomere measurement methods (digoxigenin-labeled Southern blot and Real-time PCR) in cellular senescence research. METHODS: Genomic DNA extracted from normal human fibroblasts (2BS) of different population doublings (PDs) was used as test samples. The Southern blot and Real-time PCR methods for telomere measurements were optimized. The specificity and sensitivity of digoxigenin detection system were analyzed by dot blot. The two methods were respectively used to measure parallel samples to analyze and compare their resolution and accuracy. RESULTS: Digoxigenin-labeled Southern blot system could detect less than 1 µg of human genomic DNA, but the optimal sample size was around 4-5 µg when measuring telomeres. The resolution of the Southern blot method was around 150 bp while the Real-time PCR method 300-400 bp. The former could distinguish the difference of 2 PDs for 2BS cells while the latter could not distinguish the difference of less than 5 PDs. The measurement error of the repeated measurements for the Real-time PCR method was more than 10% which was bigger than that of the Southern blot method (2.5%, P<0.001). CONCLUSION: Digoxigenin-labeled Southern blot system is fully applicable to telomere measurement. The performance of the Southern blot method is better than that of the Real-time PCR method while the latter is convenient and high-throughput. In the study of cellular senescence, the appropriate method should be selected according to specific experiment.

Radiological and Clinical Outcomes comparing 2-level MIS Lateral and MIS Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spinal Stenosis.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVES: To compare early postoperative radiological and clinical outcomes between 2-level minimally invasive (MIS) trans-psoas lateral lumbar interbody fusion (LLIF) and MIS transforaminal lumbar interbody fusion (TLIF) for degenerative lumbar spinal stenosis. METHODS: Fifty three consecutive patients undergoing 2-level lumbar interbody fusion from L3-L5 for degenerative lumbar spinal stenosis were enrolled. Twenty four patients underwent LLIF and 29 underwent TLIF. RESULTS: Operative time and length of stay were similar between LLIF and TLIF (272.8 ± 82.4 vs 256.1 ± 59.4 minutes; 5.5 ± 2.8 vs 4.7 ± 3.3 days, P > .05), whereas blood loss was lower for LLIF (229.0 ± 125.6 vs 302.4 ± 97.1mls, P = .026). Neurological deficits were more common in LLIF (9 vs 3, P = .025), whereas persistent deficits were rare for both (1 vs 1, P = 1). For both groups, all patient reported outcomes visual analogue scale (VAS back pain, VAS leg pain, ODI, SF-36 physical) improved from preoperative to 2-years postoperative (P < .05), with both groups showing no significant differences in extent of improvement for any outcome. Lateral lumbar interbody fusion demonstrated superior restoration of disc height (L3-L4: 4.1 ± 2.4 vs 1.2 ± 1.9 mm, P < .001; L4-L5: 4.6 ± 2.4 vs .8 ± 2.8 mm, P < .001), foraminal height (FH) (L3-L4: 3.5 ± 3.6 vs 1.0 ± 3.6 mm, P = .014; L4-L5: 3.0 ± 3.5 vs -.1 ± 4.4 mm, P = .0080), segmental lordosis (4.1 ± 6.4 vs -2.1 ± 8.1°, P = .005), lumbar lordosis (LL) (4.1 ± 7.0 vs -2.3 ± 12.6°, P = .026) and pelvic incidence-lumbar lordosis (PI-LL) mismatch (-4.1 ± 7.0 vs 2.3 ± 12.6°, P = .019) at 2-years follow-up. CONCLUSION: The superior radiological outcomes demonstrated by 2-level trans-psoas LLIF did not translate into difference in clinical outcomes compared to 2-level TLIF at the 2-years follow-up, suggesting both approaches are reasonable for 2-level lumbar interbody fusion in degenerative lumbar spinal stenosis.

Melioidosis-related mycotic aneurysm: Three cases.

BACKGROUND: Melioidosis-related mycotic aneurysm (MA) is rare but a potentially life-threatening disease with high morbidity and mortality rate. CASE PRESENTATION: We report a case series of mycotic aneurysm caused by Burkholderia pseudomallei and the subsequent outcomes. Here, we illustrate their clinical characteristics, laboratory results, radiological findings, mode of therapies and clinical outcomes. CONCLUSION: Melioidosis-associated MA may manifest in an atypical presentation. Its outcome is often lethal if antimicrobial therapy and surgical intervention are not offered promptly.

Hydrogen peroxide induces p16(INK4a) through an AUF1-dependent manner.

Elevation of p16(INK4a) has been described as an important mechanism for hydrogen peroxide (H2O2)-induced replicative senescence. However, the mechanisms underlying remain unknown. In this study, we demonstrate an important role of RNA-binding protein AUF1-mediated mRNA turnover in H2O2-induced p16(INK4a) expression. The induction of p16 by H2O2 was accompanied with declined cytoplasmic AUF1 level. Accordingly, exposure of cells to H2O2 remarkably reduced the binding of AUF1 to p16 3'UTR and increased the half-life of an EGFP-p16-3'UTR chimeric transcript. In AUF1-silenced cells, the effect of H2O2 on p16 induction was abolished. Furthermore, in cells co-transfected with vectors expressing AUF1s, treatment with H2O2 failed to significantly reduce the expression of AUF1 and subsequently elevate the levels of p16. Moreover, HeLa cells overexpressing AUF1s were resistant to H2O2-induced senescence. Our results indicate that AUF1 is critical for H2O2-induced p16 expression and cellular senescence.

Paradoxical effects of cellular senescence-inhibited gene involved in hepatocellular carcinoma migration and proliferation by ERK pathway and mesenchymal-like markers.

BACKGROUND: Cellular senescence-inhibited gene (CSIG) strongly prolongs the progression of replicative senescence. However, roles and mechanisms of CSIG in tumor progression have not been studied widely. METHODS: Roles of CSIG in migration and proliferation of SMMC7721 and Huh7 cells were analyzed by transwell or cell viability assays, respectively. Tumorigenicity assays were used to study whether CSIG knockdown could affect SMMC7721 proliferation in vivo. Next, Western blotting and RT-PCR were preformed to evaluate the effects of CSIG on P-ERK cascade and epithelial mesenchymal transformation markers. Then, the location and expression of CSIG protein was detected by immunofluorescence and Western blotting, respectively. Finally, the Cancer Genome Atlas dataset was used to analyze CSIG mRNA levels in hepatocellular carcinoma (HCC) and adjacent non-tumor tissues. RESULTS: In this study, we found that CSIG overexpression promoted SMMC7721 cell migration, and CSIG knockdown suppressed tumorigenicity of SMMC7721 cells. In contrast to expectation, CSIG up-regulation could significantly inhibit Huh7 cell growth and migration. CSIG could promote P-ERK activation and levels of mesenchymal-like markers in SMMC7721 cells, whereas CSIG suppressed P-ERK activation and levels of mesenchymal-like markers in Huh7 cells. CSIG protein was located in nucleoli as well as nucleoplasm of SMMC7721 cells, whereas CSIG protein was mainly expressed in the nucleoli rather than nucleoplasm of Huh7 cells. Finally, due to individual differences, raised or down-regulated trends of CSIG in HCC as compared with adjacent non-tumor tissues are different among various patient populations. CONCLUSION: In summary, these results indicate that CSIG might play different roles in SMMC7721 and Huh7 cells through regulating P-ERK pathway and mesenchymal-like markers. The differential distribution of CSIG might be an important factor that causes its different functions in SMMC7721 and Huh7 cells. CSIG might play different roles in various patient populations.

Early clinical outcomes of the domestic KokaclipTM transcatheter edge-to-edge mitral valve repair system for severe degenerative mitral regurgitation: A single-arm, prospective, single-group target value clinical trial / 中国胸心血管外科临床杂志

@#Objective To summarize and analyze the preliminary clinical outcomes of the KokaclipTM transcatheter edge-to-edge mitral valve repair system for severe degenerative mitral regurgitation (DMR). Methods This study was a single-arm, prospective, single-group target value clinical trial that enrolled patients who underwent the KokaclipTM transcatheter edge-to-edge repair (TEER) system for DMR in the Department of Heart Surgery of Guangdong Provincial People's Hospital, Guangdong Cardiovascular Institute from June 2022 to January 2023. Differences in the grade of mitral regurgitation (MR) during the perioperative and follow-up periods were compared, and the incidences of adverse events such as all-cause death, thoracotomy conversion, reoperation, and severe recurrence of MR during the study period were investigated. Results The enrolled patient population consisted of 14 (50.0%) females with a mean age of 70.9±5.4 years. Twenty-eight (100.0%) patients were preoperatively diagnosed with typeⅡ DMR, with a prolapse width of 12.5 (11.0, 16.1) mm, a degree of regurgitation 4+ leading to pulmonary venous reflux, and a New York Heart Association cardiac function class≥Ⅲ. All patients completed the TEER procedure successfully, with immediate postoperative improvement of MR to 0, 1+, and 2+ grade in 2 (7.1%), 21 (75.0%), and 5 (17.9%) patients, respectively. Mitral valve gradient was 2.5 (2.0, 3.0) mm Hg. Deaths, thoracotomy conversion, or device complications such as unileaflet clamping, clip dislodgement, or leaflet injury were negative. Twenty-eight (100.0%) patients completed at least 3-month postoperative follow-up with a median follow-up time of 5.9 (3.6, 6.8) months, during which patients had a mean MR grade of 1.0+ (1.0+, 2.0+) grade and a significant improvement from preoperative values (P<0.001). There was no recurrence of ≥3+ regurgitation, pulmonary venous reflux, reoperation, new-onset mitral stenosis, or major adverse cardiovascular events. Twenty-two (78.6%) patients’ cardiac function improved to classⅠorⅡ. Conclusion The domestic KokaclipTM TEER system has shown excellent preliminary clinical results in selected DMR patients with a high safety profile and significant improvement in MR. Additional large sample volume, prospective, multicenter studies, and long-term follow-up are expected to validate the effectiveness of this system in the future.

Two isomers of HDTIC isolated from Astragali Radix decrease the expression of p16 in 2BS cells.

BACKGROUND: Astragali Radix, the root of Astragalus membranceus (Fish) Bunge Var. mongholicus (Bge), is a crude drug considered as one of the effective traditional Chinese anti-ageing material. The two isomers of 4-hydroxy-5-hydroxymethyl-[1, 3] dioxolan-2, 6'-spirane-5', 6', 7', 8'-tetrahydro-indolizine-3'-carbaldehyde (HDTIC), HDTIC-1 and HDTIC-2, were first extracted from the herb in 2002. We demonstrated previously that 0.1 micromol/L HDTIC-1 or 1.0 micromol/L HDTIC-2 strongly delay replicative senescence of human fetal lung diploid fibroblasts (2BS). In this study, we chose them to investigate their effects on the expression of senescence-associated genes to explore the mechanism of how HDTIC delays replicative senescence. METHODS: The effects of HDTIC-1 and HDTIC-2 on the expression of p16 and p21 were observed in vitro by RT-PCR and Western blot. The anti-oxidative activities of the compounds were also observed by phenotype alteration after treatment with antioxidants. RESULTS: There was an obvious expression of p16 in the control senescent cells. However, in the 2BS cells, after 56 population doublings (PDs) grown from PD28 in 0.1 micromol/L HDTIC-1 or 1.0 micromol/L HDTIC-2, there was a weak mRNA expression of p16 and no protein expression of p16 was observed. The expression level of p21 increased with cell ageing. Moreover, there was no difference between the expression level of p21 in the control cells and that in the same PD cells cultured with HDTIC compounds. The results also showed that 2BS cells exposed to 100 micromol/L H2O2 for 5 minutes return to their non-senescent phenotype and continue to be confluent after incubating the damaged cells with HDTIC-1 (1.0 micromol/L ) or HDTIC-2 (10 micromol/L ) for 1 hour. CONCLUSIONS: Expression of p16 by 2BS cells was strongly inhibited by HDTIC compounds, which could contribute to their delayed replicative senescence by the way of p16(INK4a)/Rb/MAPK. The anti-oxidative activities of HDTIC-1 and HDTIC-2, described in this study for the first time, might be indirectly related to their inhibition of p16 expression.

Comparison of sternotomy and thoracoscopic extended myectomy in the treatment of elderly patients with hypertrophic obstructive cardiomyopathy / 中华老年医学杂志

Objective:To evaluate the clinical effectiveness of thoracoscopic extended septal myectomy in elderly patients diagnosed with hypertrophic obstructive cardiomyopathy(HOCA).Methods:From April 2019 to August 2021, 36 elderly patients with HOCM who underwent septal myectomy were retrospectively analyzed, including 20 patients under thoracoscopy and 16 patients under median sternotomy.The surgical outcomes, echocardiography and follow-up results were compared between the two groups.Results:The number of intracardiac incisions in the Thoracoscopy group was significantly lower than that in the median thoracotomy group( P=0.001).Additionally, the ventilation time of ≤24 hours was higher in the thoracoscopy group compared to the median thoracotomy group(75.0% vs 31.2%, P=0.017).It is noteworthy that there were no deaths in the thoracoscopic group.However, one patient experienced left ventricular rupture during mitral valve replacement and had to be converted to median sternotomy.This patient also developed low cardiac output syndrome after the operation but was discharged smoothly.In the median sternotomy group, one patient died in the hospital, two patients developed low cardiac output syndrome, and one patient underwent re-sternotomy due to bleeding.Importantly, neither group experienced ventricular septal perforation or complete atrioventricular block.The number of intracardiac incisions in the thoracoscopy postoperative interventricular septal thickness was significantly reduced in both groups.In the thoracoscopic group, the interventricular septal thickness was(19.2±3.5)mm and(11.3±2.2)mm, with a t-value of 8.531 and a p-value of <0.001.In the median sternotomy group, the interventricular septal thickness was(19.9±3.9)mm and(13.1±2.6)mm, with a t-value of 5.664 and a p-value of <0.001.This reduction effectively relieved left ventricular outflow tract obstruction.In the thoracoscopic group, the left ventricular outflow tract obstruction decreased from(96.2±32.9)mmHg to(8.2±3.4)mmHg, with a t-value of 11.894 and a p-value of <0.001.In the median sternotomy group, the left ventricular outflow tract obstruction decreased from(83.2±40.9)mmHg to(13.3±19.3)mmHg, with a t-value of 5.997 and a p-value of <0.001.The patients in the thoracoscopic group were followed up for an average of(13.5±8.8)months, and no complications occurred.The patients in the median sternotomy group were followed up for an average of(15.8±9.4)months.One patient in this group underwent alcohol septal ablation for residual obstruction and developed complete atrioventricular block. Conclusions:Thoracoscopic extended myectomy in elderly patients with(HOCM)can achieve comparable therapeutic effectiveness and safety compared to the median sternotomy approach.This minimally invasive procedure is associated with shorter ventilation time and can also minimize the need for additional intracardiac incisions, especially when simultaneous mitral valve treatment is necessary.

Effect analysis of myectomy guided by personalized three-dimensional reconstruction and printing in the treatment of obstructive hypertrophic cardiomyopathy / 中华外科杂志

Objective: To examine the clinical efficacy of myectomy guided by personalized three-dimensional reconstruction and printing for patients with obstructive hypertrophic cardiomyopathy. Methods: The clinical data of 28 patients with obstructive hypertrophic cardiomyopathy, who underwent septal myectomy guided by personalized three-dimensional reconstruction and printing in the Department of Cardiaovascular Surgery, Guangdong Provincial People's Hospital from May 2020 to December 2021, were retrospectively analyzed. There were 14 males and 14 females, aging (51.1±14.0) years (range: 18 to 72 years). Enhanced cardiac computed tomography images were imported into Mimics software for preoperative three-dimensional reconstruction. The direction of the short axial plane of each segment was marked perpendicularly to the interventricular septum on the long axial plane of the digital cardiac model, then the thickness was measured on each short axial plane. A figurative digital model was used to determine the extent of resection and to visualize mitral valve and papillary muscle abnormalities. Correlation between the length, width, thickness, and volume of the predicted resected myocardium and those of the surgically resected myocardium was assessed by Pearson correlation analysis or Spearman correlation analysis. The accuracy of detecting mitral valve and papillary muscle abnormalities of transthoracic echocardiography and three-dimensional reconstruction was also compared. Results: There was no death or serious complications like permanent pacemaker implantation, re-sternotomy for bleeding, low cardiac output syndrome, stroke, or multiple organ dysfunction syndromes in the whole group. Namely, the obstruction of the left ventricular outflow tract was effectively relieved. The systolic anterior motion of the anterior mitral valve leaflet was absent in all patients after myectomy. The length, width, and thickness of the predicted resected myocardium by three-dimensional reconstruction were significantly positively correlated with the length (R=0.65, 95%CI: 0.37 to 0.82, P<0.01), width (R=0.39, 95%CI: 0.02 to 0.67, P<0.01), and thickness (R=0.82, 95%CI: 0.65 to 0.92, P<0.01) of the surgically resected myocardium, while the relation of the volume of the predicted resected myocardium and the volume of the surgically resected myocardium was a strong positive correlation (R=0.88, 95%CI: 0.76 to 0.94, P<0.01). Importantly, the interventricular septal myocardial thickness measured by preoperative transthoracic echocardiography showed a moderate positive correlation with the volume of surgically resected myocardium (R=0.52, 95%CI: 0.19 to 0.75, P<0.01). During a follow-up of (14.4±6.8) months (range: 3 to 22 months), no death occurred, and 1 patient was readmitted for endocardial radiofrequency ablation due to atrial fibrillation. Conclusion: Personalized three-dimensional reconstruction and printing can not only visualize the intracardiac structure but also guide septal myectomy by predicting the thickness, volume, and extent of resected myocardium to achieve ideal resection.

Early outcomes of thoracoscopic trans-mitral myectomy in obstructive hypertrophic cardiomyopathy patients with left midventricular obstruction / 中华外科杂志

Objective: To examine the early effect of thoracoscopic trans-mitral myectomy for hypertrophic cardiomyopathy patients with left midventricular obstruction. Methods: From April 2020 to July 2021, 10 hypertrophic cardiomyopathy patients with left midventricular obstruction underwent thoracoscopic trans-mitral myectomy at Guangdong Provincial People's Hospital. The whole group of patients consisted of 7 males and 3 females aged (52.0±16.4) years (range: 18 to 68 years). The EuroSCORE Ⅱ predicted mortality rate was 1.78% (1.20%) (M(IQR)) (range: 0.96% to 4.86%). The clinical data were collected and analyzed retrospectively to evaluate the clinical efficacy by comparing preoperative and postoperative echocardiographic parameters using paired t-test, paired Wilcoxon test or Fisher exact test, including left ventricular outflow tract peak pressure gradient, maximum interventricular septum thickness, systolic anterior motion of the anterior mitral leaflet and so on. The safety was determined by summarizing the incidence of perioperative and follow-up complications. Results: All the procedures successed with no conversion to median sternotomy, septal defect, ventricular rupture. There was no in-hospital 30-day death, neither serious complications like permanent pacemaker implantation, re-sternotomy for bleeding, low cardiac output syndrome, stroke, or multiple organ dysfunction syndrome. The left ventricular outflow tract obstruction was effectively relieved in all patients expect a patient developed residual obstruction. Compared with that of pre-operation, the thickness of the interventricular septum was significantly reduced from (22.1±4.0) mm to (10.3±1.7) mm (t=10.693, P<0.01), while the left ventricular outflow tract peak pressure gradient was significantly reduced from (81.7±21.1) mmHg to 12.3 (11.5) mmHg (Z=-2.805, P<0.01) (1 mmHg=0.133 kPa). Conclusion: Thoracoscopic trans-mitral myectomy is an effective and safe procedure for hypertrophic cardiomyopathy patients with left midventricular obstruction.

Preliminary clinical outcomes of the domestic Renatus® balloon-expandable valve system for the treatment of severe aortic stenosis: A prospective cohort study / 中国胸心血管外科临床杂志

@#Objective     To evaluate the early clinical outcomes of the Renatus® balloon-expandable valve in the treatment of severe aortic stenosis. Methods    From November 2021 to April 2022, a total of 38 patients who received Renatus® balloon-expandable valve for severe aortic stenosis in Guangdong Provincial People's Hospital were included. There were 22 males and 16 females, with an average age of 73.7±5.3 years. Mean aortic gradient and peak aortic jet velocity at baseline, post-procedure, and follow-up were compared. Clinical outcomes including all-cause mortality, perivalvular leakage, serious adverse cardiovascular events and the occurrence of permanent pacemaker implantation were assessed. Results    All patients completed the procedure successfully without conversion to thoracotomy or perioperative death. The post-implant mean aortic pressure gradient was decreased from 41.5 (27.8, 58.8) mm Hg to 6.0 (3.0, 8.0) mm Hg, and the peak aortic jet velocity was also decreased from 4.1±0.9 m/s to 1.7±0.4 m/s (P<0.001). Pacemakers were required in 2 (5.3%) patients. The median follow-up time was 27.5 (23.0, 87.5) d, with a follow-up rate of 100.0%. The mean aortic gradient was 8.0 (7.0, 10.8) mm Hg and peak aortic jet velocity was 2.0±0.3 m/s, showing significant improvement compared with those in the preoperative period (P<0.001). No severe aortic regurgitation or paravalvular leak was observed. There was no serious cardiovascular adverse event or reoperative event during the study period. Conclusion    Transcatheter aortic valve replacement with the domestic Renatus® balloon-expandable valve system is a safe and effective procedure for selected patients with severe aortic stenosis who are at high risk or not candidates for surgical aortic valve replacement.

Clinical efficacy and survival analysis of totally thoracoscopic redo mitral valve replacement / 中国胸心血管外科临床杂志

@#Objective     To analyze the clinical efficacy and survival outcome of totally thoracoscopic redo mitral valve replacement and evaluate its efficiency and safety. Methods     The clinical data of patients with totally thoracoscopic redo mitral valve replacement in Guangdong Provincial People’s Hospital between 2013 and 2019 were retrospectively analyzed. Survival analysis was performed using the Kaplan-Meier method. Univariate and multivariate Cox regression analyses were used to determine the risk factors for postoperative death. Results     There were 48 patients including 29 females and 19 males with a median age of 53 (44, 66) years. All the procedures were performed successfully with no conversion to median sternotomy. A total of 15, 10 and 23 patients received surgeries under non-beating heart, beating heart and ventricular fibrillation, respectively. The in-hospital mortality rate was 6.25% (3/48), and the incidence of early postoperative complications was 18.75% (9/48). Thirty-five (72.92%) patients had their tracheal intubation removed within 24 hours after the operation. The 1- and 6-year survival rates were 89.50% (95%CI 81.30%-98.70%) and 82.90%(95%CI 71.50%-96.20%), respectively. Age>65 years was an independent risk factor for postoperative death (P=0.04). Conclusion     Totally thoracoscopic redo mitral valve replacement is safe and reliable, with advantages of rapid recovery, reducing blood transfusion rate, reducing postoperative complications and acceptable long-term survival rate. It is worthy of being widely popularized in the clinic.

Totally endoscopic transmitral septal myectomy for the treatment of recurrent left ventricular outflow tract obstruction after alcohol septal ablation / 中国胸心血管外科临床杂志

@#Objective    To investigate the surgical strategies and clinical efficacy of transmitral septal myectomy in the treatment of recurrent left ventricular outflow tract obstruction (LVOTO) after alcohol septal ablation. Methods    The clinical data of patients with recurrent LVOTO after alcohol septal ablation from July 2020 to July 2021 in the Department of Cardiac Surgery, Guangdong Provincial People's Hospital were retrospectively analyzed. Patients were preoperatively evaluated by echocardiography, cardiac magnetic resonance imaging, cardiac computed tomography, 3D modeling and printing technology. A personalized surgical strategy was preoperatively developed according to multimodality imaging assessment, while visual exploration was performed on the digital model and simulated surgical resection was performed on the printed model. Results     Two female patients were enrolled, aged 62 years and 64 years, respectively. Totally endoscopic transmitral extended myectomy was successfully performed on both patients with aortic cross-clamping time of 96 min and 85 min, respectively. LVOTO was relieved immediately (subaortic peak pressure gradient decreased from 100 mm Hg to 4 mm Hg and from 84 mm Hg to 6 mm Hg, respectively) and the mitral regurgitation significantly improved after the procedure. No patient had complete atrioventricular block or required permanent pacemaker implantation. The patients were discharged uneventfully without postoperative complications. Conclusion    Personalized totally endoscopic transmitral extended myectomy combined with multimodality imaging assessment and 3D modeling and printing has an acceptable clinical effect in patients with recurrent LVOTO after alcohol septal ablation. The procedure can precisely resect the hypertrophic septal myocardium while avoiding serious complications such as septal perforation or complete atrioventricular block.

Transapical approach under 3D printing guidance for myectomy in apical hypertrophic cardiomyopathy: A case report / 中国胸心血管外科临床杂志

@#We reported a 26-year-old male who was diagnosed with apical hypertrophic cardiomyopathy with left ventricular aneurysm. The location of the hypertrophic myocardium and the extent of resection were accurately assessed preoperatively using 3D modeling and printing technology. Myectomy was performed via transapical approach, and the intraoperative exploration was consistent with the description of the preoperative 3D modeling. The patient underwent the surgery successfully without any complications during the hospitalization, and the cardiopulmonary bypass time was 117 min, the aortic cross-clamping time was 57 min, and the hospital stay time was 7 d. The postoperative echocardiography demonstrated left ventricular cavity flow patency. This case provides a reference for the management of patients with apical hypertrophic cardiomyopathy.

Clinical study of intercondylar fossa formation to prevent intercondylar fossa impingement after high tibia osteotomy / 中国骨伤

OBJECTIVE@#To observe the clinical efficacy of intercondylar fossa plasty in preventing intercondylar fossa impingement syndrome after high tibial osteotomy.@*METHODS@#From August 2018 to August 2020, 84 patients with inverted knee osteoarthritis were treated by arthroscopy combined with high tibial osteotomy, and were divided into two groups with 42 cases in each group according to different surgical methods. In the intercondylar fossa plasty group, there were 13 males and 29 females, age ranged from 52 to 67 years old with an average of(58.27±4.32) years old, and arthroscopic intercondylar fossa plasty was performed first, and then high tibial osteotomy. In the arthroscopic cleansing group, 16 males and 26 females, age ranged from 50 to 71 years old with an average of (59.02±5.14) years old, underwent arthroscopic cleansing and then high tibial osteotomy. Postoperative treatment was evaluated using visual analogue scale(VAS), hospital for special surgery (HSS) score for the knee, and the occurrence of intercondylar percussa impingement.@*RESULTS@#All 84 patients were followed up, the duration ranged from 12 to 18 months with an average of (14.1±1.6) months. The VAS and HSS score of knee joint at 6, 12 and 18 months after surgery were significantly improved compared with preoperative period, and there was no significant difference between the two groups (P>0.05), but the incidence of intercondylar fossa index and intercondylar fossa impact between the two groups was significantly compared 18 months after surgery (P<0.05).@*CONCLUSION@#Intercondylar fossa plasty can effectively prevent the incidence of intercondylar fossa impact after high tibial osteotomy, and has a more significant effect on postoperative knee pain and function improvement.

Aminoguanidine delays the replicative senescence of human diploid fibroblasts.

BACKGROUND: The accumulation of free radicals and advanced glycation end products (AGEs) in cell plays a very important role in replicative senescence. Aminoguanidine (AG) has potential antioxidant effects and decreases AGE levels. This study aimed to investigate its effect on replicative senescence in vitro. METHODS: The effects of aminoguanidine on morphology, replicative lifespan, cell growth and proliferation, AGEs, DNA damage, DNA repair ability and telomere length were observed in human fetal lung diploid fibroblasts (2BS). RESULTS: Aminoguanidine maintained the non-senescent phenotype of 2BS cells even at late population doubling (PD) and increased cumulative population doublings by at least 17 - 21 PDs. Aminoguanidine also improved the potentials of growth and proliferation of 2BS cells as detected by the MTT assay. The AGE levels of late PD cells grown from early PD in DMEM containing aminiguanidine decreased significantly compared with those of late PD control cells and were similar to those of young control cells. In addition, the cells pretreated with aminoguanidine had a significant reduction in DNA strand breaks when they were exposed to 200 micromol/L H(2)O(2) for 5 minutes which indicated that the compound had a strong potential to protect genomic DNA against oxidative stress. And most of the cells exposed to 100 micromol/L H(2)O(2) had much shorter comet tails and smaller tail areas after incubation with aminoguanidine-supplemented DMEM, which indicated that the compound strongly improved the DNA repair abilities of 2BS cells. Moreover, PD55 cells grown from PD28 in 2 mmol/L or 4 mmol/L aminoguanidine retain telomere lengths of 7.94 kb or 8.12 kb, which was 0.83 kb or 1.11 kb longer than that of the control cells. CONCLUSION: Aminoguanidine delays replicative senescence of 2BS cells and the senescence-delaying effect of aminoguanidine appear to be due to its many biological properties including its potential for proliferation improvement, its inhibitory effect of AGE formation, antioxidant effect, improvement of DNA repair ability and the slowdown of telomere shortening.

Posttranscriptional induction of p21Waf1 mediated by ectopic p16INK4 in human diploid fibroblast.

BACKGROUND: Both p16(INK4) and p21(Waf1) are tumor suppressors with similar biological functions in the regulation of cellular senescence. Previous reports showed that p16(INK4) could be activated by p21(Waf1) through transcriptional factor Sp1 in HeLa cells. This study was undertaken to determine the effects of p16(INK4) on the expression and functions of p21(Waf1). METHODS: Human diploid fibroblast 2BS cells were stably transfected with sense (2BS/p16(INK4)), antisense p16(INK4) (2BS/asp16(INK4)) or empty vector (2BS/neo). Then they were assayed by reverse-transcription polymerase chain reaction (RT-PCR), fluorescence activated cell sorting (FACS) and Western blot. RESULTS: 2BS/p16(INK4) cells exhibited cell cycle arrest in both G1 and G2/M phases. Endogenous p21(Waf1) protein levels increased twofold in the 2BS/p16(INK4) cells, but not decreased in the 2BS/asp16(INK4) cells. p21(Waf1) mRNA levels were not affected in neither 2BS/p16(INK4) nor 2BS/asp16(INK4) cells. CONCLUSION: p16(INK4) may play an important role in the regulation of cellular senescence by modulating the p21(Waf1) protein level via the posttranscriptional mechanism.

Optimization of reporter gene assay: several factors influencing detection of promoter activity.

BACKGROUND: Promoter analysis is currently applied to detect the expression of the targeted gene in studies of signal transduction and transcriptional regulation. As a reporter gene, luciferase plays an important role and has been used widely in the promoter assay. METHODS: Human embryonic lung fibroblast cells (2BS), HeLa cells and MCF-7 cells were transfected with various genes embedded by lipofectamine. This study determined various factors that affect promoter activity determination, such as the selection of the reporter genes and internal references, the dose and the type of the vectors carrying the transcription factors, the host cells and the instruments. RESULTS: The sensitivity of the luciferase assay was much higher than that of enhanced green fluorescence protein (EGFP). Moreover, promoter activity is increased in a dose-related manner only in certain ranges outside of which the results may be reversed and the promoter activity is related to the expression vector which is carrying the cDNA. Otherwise, the length of the promoter, internal references and the host cell can also influence the promoter activity. CONCLUSIONS: To detect the promoter activity accurately, a few factors including dose, vector, length and host cell which influence reporter gene assay aforementioned should be considered.