Along with the coming of aged society, the prevalence of heart valvular disease is significantly increasing, and the use of bioprosthetic valves for treating patients with severe valve disease has increased over the last two decades. As a consequence, a growing number of patients with surgical bioprosthesis degeneration is predicted in the near future. In this setting, valve-in-valve (ViV) transcatheter aortic/mitral valve replacement (TAVR/TMVR) has emerged as an alternative to redo surgery. A deep knowledge of the mechanism and features of the failed bioprosthetic heart valve is pivotal to plan an adequate procedure. Multimodal imaging is fundamental in the diagnostic and pre-procedural phases. The immediate and mid-term clinical and hemodynamic results have demonstrated the safety and feasibility of ViV techniques, but the development of these techniques faces several specific challenges, such as coronary obstruction, potential post-procedural mismatch and leaflet thrombosis. This article reviews the current status and prospects of ViV-TAVR technology in the treatment for biological valve degeneration, and suggests that ViV-TAVR should be promoted and implemented in existing medical centers with good surgical aortic valve replacement experience, so as to provide better treatment for patients.
Objective To evaluate clinical efficacy of four-claw Ti-planes for internal fixation of multiple rib fractures and flail chest. Methods Clinical data of 93 patients with multiple rib fractures and flail chest who were admittedto Shanghai Pudong Hospital from December 2011 to November 2012 were retrospectively analyzed. There were 78 male and 15 female patients with their age of 20-80 years. All the patients received internal fixation of rib fractures using four-clawTi-planes. Finite element modeling and analysis were performed to investigate biomechanical behaviors of rib fractures after internal fixation with four-claw Ti-planes. Results The average number of rib fractures of the 93 patients was 5.9±2.1，and each patient received 3.8±1.3 four-claw Ti-planes for internal fixation. The operations were performed 6.3±3.2 days after admission. After the rib fractures were fixed with four-claw Ti-planes，rib dislocations and chest-wall collapse of flail chest were restored，and patients’ pain was relieved. Postoperative CT image reconstruction of the chest showed no dislocationor displacement at the fixation areas of the four-claw Ti-planes. Rib fractures were stabilized well，and normal contours of the chest were restored. Finite element analysis showed that the maximum bearable stress of the rib fractures after internal fixation with four-claw Ti-planes was twice as large as normal ribs. Conclusion Clinical outcomes of four-claw Ti-planesfor internal fixation of rib fractures are satisfactory with small incisions and less muscle injury of the chest wall，so this technique deserves wide clinical use.
Objective To investigate the effects of 1, 25-( OH) 2D3 on the expression of matrix metalloprotease-9 ( MMP-9) and nuclear factor κB ( NF-κB) activity in a murine model of chronic asthma. Methods BALB/ c mice were sensitized and challenged with ovalbumin to establish chronic asthmatic model. The animals were randomly divided into a control group, an asthma group and a VD group. Lung sections from the mice were stained by HE and Masson’s trichrome, respectively. Morphometric analysis of the stained sections was performed using computerized image analysis system. Nuclear translocation of NF-κB p65 was examined using Western blot. The level of IκBαwas detected with real-time quantitative PCR ( RTPCR) and Western blot. In addition, the expression of MMP-9 in both activity and mRNA level was detected by gelatin zymograph and RT-PCR, respectively. Results Prominent airway remodeling developed in the asthma group, including the inflammatory cell infiltration, subepithelial collagen deposition and increased airway smooth muscle mass. In contrast, 1, 25-( OH) 2D3 attenuated these established structural changes of the airways. Stimulation with OVA induced a 7. 87-fold increase in the MMP-9 activity compared with that in the control group, and 1, 25-( OH) 2D3 treatment only induced a 3. 46-fold increase in the MMP-9 activity compared with that in the control group ( P lt;0. 05) . The mRNA level of MMP-9 in the VD group ( 3.16 ± 0.09) was decreased compared with the asthma group ( 5.74 ±0.13) ( P lt;0.05) , but itwas still higher than that in the control group ( 0.57 ±0.08) ( P lt;0.05) . 1, 25-( OH) 2D3 reduced the nuclear translocation of NF-κB p65 while up-regulated the IκBα level in lung tissue of chronic asthma. Conclusions 1, 25- ( OH) 2D3 can inhibit the NF-κB activity and down-regulate the expression of MMP-9 in lung tissue of chronic asthma, thus alleviating the established chronic asthma-induced airway remodeling.
Objective
To investigate the effects of transforming growth factor beta (TGF-β) on airway remodeling in obese asthmatic mice and intervention effects of pirfenidone.
Methods
Seventy-five C57BL/6J mice were randomly divided into five groups, namely a blank control group (group A), an obese group (group B), an obese asthmatic group (group C), a budesonide treatment group (group D) and a pirfenidone treatment group (group E). The mice in the B, C, D, and E groups were fed with high fat diets, then the mice in the C, D, and E groups were sensitized and challenged with ovalbumin (OVA) to establish the model of chronic obese asthma. The mice in group A were fed with normal diets, sensitized and challenged with normal saline. The mice in group D were treated with budesonide (0.5 mg/ml), and the mice in group E were treated with pirfenidone (300 mg/kg). After 4 weeks of treatment, the total number of white cells as well as the percentage of leukocytes, eosinophils, neutrophils and macrophage in bronchoalveolar lavage fluid (BALF) were counted. ELISA and Western blot were used to evaluate the expression of TGF-β. The pathological changes of mice were observed under light microscope by HE and periodic acid-Schiff staining. Meanwhile the remodeling indices were measured including total bronchial wall area (WAt), smooth muscle area (WAm), and bronchial basement membrane perimeter (Pbm).
Results
The levels of leukocyte and eosinophils in BALF, expression of TGF-β, WAt/Pbm and WAm/Pbm in group C were higher than those in group A, B, D, and E (allP<0.05). The levels of eosinophils in BALF, WAt/Pbm in group E were lower than those in group D (allP<0.05). The level of TGF-β decreased in a sequence of group C>D>E>B>A (allP<0.05). The expression of TGF-β was in a positive correlation with eosinophil percentage in BALF (r=0.79,P<0.01).
Conclusions
The expression of TGF-β in the airway of obese asthmatic mice is closely related to airway inflammation, airway hyper-secretion and airway remodeling. Pirfenidone can effectively inhibit the expression of TGF-β and improve airway remodeling.
Objective
By observation of the diameter, progression rate, wall thickness, and the opening angle of the abnormal aortic of abdominal aortic aneurysm (AAA) in rats, to observe the effect of saturated hydrogen saline on residual strain of AAA rats, and to investigate its inhibition effect on AAA formation.
Methods
Twenty healthy male Sprague Dawley rats (weighing, 200-220 g) were randomly divided into 2 groups, which was made the AAA model by infiltration of the abdominal arota with 0.5 mol/L calcium chloride. Saturated hydrogen saline (5 mL/kg) or saline (5 mL/kg) was injected intraperitoneally in the experimental group or control group respectively, every day for 28 days. At 28 days, the diameter, progression rate, wall thickness, and opening angle of the abnormal aorta were mearsured. The aortic tissue was harvested for histological examination (HE staining and aldehyde-fuchsin staining).
Results
At 28 days after operation, the diameter of abnormal aorta in 2 groups were significantly higher than preoperative ones (P lt; 0.05), the progression rate in experimental group (65% ± 15%) was significantly lower than that in control group (128% ± 54%) (t=3.611, P=0.005). The opening angle and the wall thickness in experimental group were (88.78 ± 29.20)° and (0.14 ± 0.03) mm respectively, had significant differences when compared with the values in control group [(44.23 ± 28.52)° and (0.36 ± 0.05) mm respectively] (P lt; 0.01). The integrity and continuity of the aortic wall in experimental group were superior to that in the control group. Compared with the control group, the injury of elastic fiber in aortic wall and the infiltration of inflammation were all reduced.
Conclusion
Saturated hydrogen saline can maintain good mechanical properties and reduce dilatation of the aorta by increasing residual strain and reducing the remodeling of it.
The Monte Carlo N-Particle (MCNP) is often used to calculate the radiation dose during computed tomography (CT) scans. However, the physical calculation process of the model is complicated, the input file structure of the program is complex, and the three-dimensional (3D) display of the geometric model is not supported, so that the researchers cannot establish an accurate CT radiation system model, which affects the accuracy of the dose calculation results. Aiming at these two problems, this study designed a software that visualized CT modeling and automatically generated input files. In terms of model calculation, the theoretical basis was based on the integration of CT modeling improvement schemes of major researchers. For 3D model visualization, LabVIEW was used as the new development platform, constructive solid geometry (CSG) was used as the algorithm principle, and the introduction of editing of MCNP input files was used to visualize CT geometry modeling. Compared with a CT model established by a recent study, the root mean square error between the results simulated by this visual CT modeling software and the actual measurement was smaller. In conclusion, the proposed CT visualization modeling software can not only help researchers to obtain an accurate CT radiation system model, but also provide a new research idea for the geometric modeling visualization method of MCNP.
ObjectiveTo review the role and mechanism of protein factors in bone remodeling, and provides theoretical basis for further elucidating the pathogenesis and clinical treatment of bone-related diseases. MethodsThe relevant research results at home and abroad in recent years were extensively consulted, analyzed, and summarized. ResultsBone remodeling is an important physiological process to maintain bone homeostasis. Protein, as an important stimulator in bone remodeling, regulates the balance between bone resorption and bone formation. ConclusionAt present, the research on the mechanism of protein in bone remodeling is insufficient. Therefore, it is necessary to further study the specific time, process, and interaction network of protein in bone remodeling, and to confirm its mechanism in bone remodeling, so as to reveal and treat the pathogenesis of bone-related diseases.
Magnetic resonance imaging (MRI)-based electroencephalography (EEG) forward modeling method has become prevalent in the field of EEG. However, due to the inability to obtain clear images of an infant’s fontanel through MRI, the fontanelle information is often lacking in the EEG forward model, which affects accuracy of modeling in infants. To address this issue, we propose a novel method to achieve fontanel compensation for infant EEG forward modeling method. First, we employed imaging segmentation and meshing to the head MRIs, creating a fontanel-free model. Second, a projection-based surface reconstruction method was proposed, which utilized priori information on fontanel morphology and the fontanel-free head model to reconstruct the two-dimensional measured fontanel into a three-dimensional fontanel model to achieve fontanel-compensation modeling. Finally, we calculated a fontanel compensation-based EEG forward model for infants based on this model. Simulation results, based on a real head model, demonstrated that the compensation of fontanel had a potential to improve EEG forward modeling accuracy, particularly for the sources beneath the fontanel (relative difference measure larger than 0.05). Additional experimental results revealed that the uncertainty of the infant’s skull conductivity had the widest impact range on the neural sources, and the absence of fontanel had the strongest impact on the neural sources below the fontanel. Overall, the proposed fontanel-compensated method showcases the potential to improve the modeling accuracy of EEG forward problem without relying on computed tomography (CT) acquisition, which is more in line with the requirements of practical application scenarios.
Abstract： Objective To investigate the effects of βreceptor blocker on intraventricular pressure gradient and left ventricle remodeling after valve replacement for critical aortic stenosis. Methods Fifty-six patients with critical aortic stenosis underwent aortic valve replacement surgery from January 2008 to January 2010 in the First Affiliated Hospital of Zhengzhou University. Thirtytwo of them who were followed up were selected to be enrolled in this study. The patients were divided into two groups under the same basis of clinical features. Twelve patients in the experimental group received oral βreceptor blocker (Metoprolol, 6.2525.00 mg once, twice daily). The rest 20 patients in the control group had no βreceptor blocker. The various indicators of ultrasound cardiogram (UCG) shortly after operation (within a week) and long after operation (6-24 months) were compared between the two groups. Results No death occurred in both groups, and chest distress, shortness of breath and other symptoms were obviously alleviated. Although left ventricular endsystolic dimension (LVESD) and left ventricular outflow tract dimension (LVOTD) of both groups increased 6-24 months after operation, compared with the early postoperative period, only the increase of LVOTD in the experimental group showed statistical difference (t=-47.937, P=0.001). In both groups, interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), filament band velocity of left ventricular outflow tract (V), intraventricular pressure gradient (G) and left ventricular mass index (LVMI) of the later period after operation were significantly lower than those of the early postoperative period. All these indicators in the experimental group showed significant differences (t=7.781, P=0.001；t=5.749, P=0.001; t=2.637, P=0.023; t=7.167, P=0.001; t=100.061, P0.001), while only V, G， and LVMI showed statistical differences in the control group (t=4.051, P=0.001; t= 4.759, P= 0.001; t=-0.166,P=0.001). EF in the experimental group also indicated significant difference compared with early period after aortic valve replacement (t=-6.621, P=0.001). EF between two groups indicated no significant difference (t=-0.354,P=0.726). But differences between the two groups in LVEDD, IVS, G， and LVMI were all statistically significant in the later period after surgery (t=-2.494, P=0.018; t=-3.434, P=0.002;t=-2.171,P=0.038; t=-2.316, P=0.028). Conclusion β-receptor blocker is a safe and reliable drug for those patients who have undergone aortic valve replacement surgery for critical aortic stenosis, and can decrease significantly the residual intraventricular pressure gradient and accelerate left ventricular cardiac remodeling.
Objective
To observe the effects of taurine on ventricular remodeling of rats with acute myocardial infarction (AMI) though the establishment of rat AMI model by ligating the left anterior descending coronary branch.
Methods
Sixty 8-week-old male Wistar rats were randomly divided into four groups: sham group, AMI group, small-dose and high-dose taurine group, with 15 rats in each. Rats in the AMI group and taurine groups received ligation of the anterior descending coronary branch to establish an animal model of AMI. Meanwhile, rats in the sham group were subjected to sham coronary ligature. From the next day of the operation, rats in the taurine groups were dosed orally per day with taurine 300 mg/kg or 400 mg/kg for 8 weeks, respectively. Echocardiographic images were acquired before and 8 weeks after the operation, to get the indexes such as left ventricular end systolic diameter (LVIDs), left ventricular end diastolic diameter (LVIDd), left ventricular posterior wall end diastolic thickness (LVPWd), left ventricular ejection fraction (LVEF), fractional shortening (FS), mitral inflow velocity E (E), mitral inflow velocity A (A), and E/A ratio, and all the measurements above were expressed as the average of 6 consecutive cardiac cycles. After the animals were executed, cardiac mass and left ventricular mass were measured, and cardiac mass index (CMI) and left ventricular mass index (LVMI) were calculated. Brain natriuretic peptide (BNP) in all groups were measured by enzyme-linked immunosorbent assay before and 8 weeks after the operation.
Results
In comparison with the AMI group, CMI, LVMI, LVIDd and LVIDs of the small-dose and high-dose taurine groups were lower, and LVPWd, LVEF, FS and E/A were higher (P<0.05). Plasma BNP level in the AMI group and two taurine-treated groups were higher than that in the sham group, and it was the highest in the AMI group (P<0.05).
Conclusion
Taurine has a protective effect on ventricular remodeling in rats with AMI, and the protective effect is dose-dependent.
