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find Keyword "modeling" 101 results
  • Effect of transcatheter aortic valve replacement on postoperative left ventricular reverse remodeling in patients with aortic regurgitation

    Objective To investigate the left ventricular reverse remodeling (LVRR) in patients with aortic valve insufficiency with reduced ejection fraction (AIrEF) and aortic valve insufficiency with preserved ejection fraction (AIpEF) after transcatheter aortic valve replacement (TAVR). MethodsThe clinical and follow-up data of patients who underwent TAVR in the Department of Cardiothoracic Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from 2018 to 2021 were retrospectively analyzed. According to the guideline, the patients with left ventricular ejection fraction<55% were allocated to an AIrEF group, and the patients with left ventricular ejection fraction≥55% were allocated to an AIpEF group. ResultsA total of 50 patients were enrolled. There were 19 patients in the AIrEF group, including 15 males and 4 females with a mean age of 74.5±7.1 years. There were 31 patients in the AIpEF group, including 19 males and 12 females with a mean age of 72.0±4.8 years. All patients underwent TAVR successfully. Echocardiographic results showed that TAVR significantly promoted LVRR in the patients. Significant LVRR occurred in the early postoperative period (the first day after the surgery) in both groups. It remained relatively stable after the LVRR in the early postoperative period (the first day after surgery) in the AIpEF patients, while it continued to occur in the early postoperative period (the first day after surgery) to three months after the surgery in the AIrEF patients, and then remained relatively stable. Compared to preoperative values, AIrEF patients had a reduction in the average left ventricular end-diastolic volume index and left ventricular end-systolic volume index by 16.8 mL/m2 (P=0.003) and 8.6 mL/m2 (P=0.005), respectively, and the average left ventricular end-diastolic diameter index and end-systolic diameter index decreased by 2.5 mm/m2 (P=0.003) and 1.9 mm/m2 (P=0.003), respectively on the first day after the surgery. In comparison to the first day after the surgery, AIrEF patients experienced an average increase of 12.1% in the left ventricular ejection fraction three months after the surgery (P<0.001). ConclusionTAVR has achieved good therapeutic effects in patients with aortic valve insufficiency, significantly promoting the LVRR in patients, and has better curative effects in AIrEF patients.

    Release date:2023-07-25 03:57 Export PDF Favorites Scan
  • RESEARCH PROGRESS OF PATHOLOGY OF ENDOCHONDRAL OSSIFICATION IN OSTEOARTHRITIS

    ObjectiveTo summarize the research progress of pathological manifestations and mechanism of endochondral ossification in osteoarthritis (OA). MethodsThe literature about endochondral ossification, bone-cartilage remodeling in OA, and joints development was reviewed, analyzed, and summarized. ResultsChondrocyte hypertrophy and apoptosis, vascular invasion, replication of the tidemark, thickening calcified cartilage, and thinning superficial cartilage are the characteristics of cartilage degeneration in OA. Articular cartilage and growth plate are similar in structure, and cartilage degeneration in OA is similar to a process of endochondral ossification of the growth plate. ConclusionLoss of stability characterization from resting metabolic balance to a high conversion state of temporary cartilage in stimulation of abnormal mechanical stresses and cytokines would subsequently contributed to continual calcification and remodeling of articular cartilage, which may be the key link of the initiation and development of OA.

    Release date:2016-12-12 09:20 Export PDF Favorites Scan
  • Internal relationship between Hippo pathway and pulmonary hypertension

    Pulmonary hypertension is a kind of progressive pulmonary vascular diseases in which there is excessive vasoconstriction and abnormal pulmonary vascular remodeling, and then a gradual increase in pulmonary arterial pressure, and it eventually leads to right ventricular failure and even death. The pathogenesis of pulmonary hypertension is still uncertain, but some studies suggest that Hippo pathway or some components of the Hippo pathway may be involved in the progress of pulmonary hypertension. In this review, we describe the mechanism of the Hippo pathway or some components of the Hippo pathway in the progress of pulmonary hypertension.

    Release date:2021-11-25 03:54 Export PDF Favorites Scan
  • ULTRASTRUCTURE OF ANTERIOR CRUCIATE LIGAMENT AFTER TRANSPLANTATION

    OBJECTIVE: To study the characteristics of, morphology histology and ultrastructure of anterior cruciate ligament(ACL) autograft and two-step cryopreserved ACL allograft after transplantation. METHODS: Sixty New Zealand rabbits and sixty Japanese rabbits were randomly divided into two groups: ACL autograft group and two-step cryopreserved ACL allograft group. Immunosuppressant were not used after transplantation. The histology and ultrastructure of the ACL of transplantation and normal knee were observed after 4 weeks and 12 weeks, respectively. RESULTS: The rate of remodeling process was faster in ACL autograft than in two-step cryopreserved ACL allograft, but there was similar remodeling process between two groups 12 weeks after transplantation. The proportions of large-diameter fibers(gt; or = 80 nm) of ACL autograft and cryopreserved ACL allograft were 6% and 24% in the 4th week, and were 0 and 2% in the 12th week, respectively. The proportions of small-diameter of fibers(lt; 80 nm) of ACL autogrft and cryopreserved ACL allograft were 94% and 76% in the 4th week, and 100% and 98% in the 12th week, respectively. Histologic incorporation in ACL autograft was similar to that in cryopreserved ACL allograft. CONCLUSION: Two-step cryopreserved bone-ACL-bone allograft were similar to bone-ACL-bone autograft cryopreserved in remodeling process and histology. The rate of remodeling process was faster in ACL autograft than in cryopreserved ACL allograft.

    Release date:2016-09-01 09:35 Export PDF Favorites Scan
  • Research Progress of Correlation between Adipocytokines and Myocardial Remodeling

    Myocardial remodeling is a common pathological physiology change for a variety of heart diseases under stimulation such as stress or ischemia. The engine body will release a lot of cytokines to promote the change of myocardial structure and ultimately lead to heart failure. Myocardial remodeling includes myocardial cells remodeling and the extracellular matrix remodeling. In recent years, we find that the function of adipose tissue is not only about energy storage, buffering to protect, supporting and filling, but also has a powerful function of secretion. Adipose tissue can secrete various adipocytokines, such as leptin, adiponectin, visfatin, omentin, angiotensin Ⅱ, and so on. Current studies have shown that adipocytokines and myocardial remodeling are intimated. And this article will summarize the function of adipocytokines on myocardial remodeling.

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  • Nontransplantation Surgical Cardiac Remodeling Operation for Endstage Cardiac Valve Disease

    Objective To evaluate the effectiveness and prospect of nontransplantation surgical cardiac remodeling for endstage cardiac valve disease by performing the remodeling operation (including anatomical and functional remodeling) after strict perioperative adjustment for endstage cardiac valve disease. Methods We retrospectively analyzed the clinical data of 31 patients, including 14 males and 17 females, with endstage cardiac valve disease who were treated with surgical cardiac remodeling operation from December 2005 to July 2009 in the 2nd Hospital of Anhui Medical University . Their age ranged from 27 to 74 years with an average age of 40.4 years. Continuous renal replacement therapy (CRRT) was carried out 3 days before surgery in all patients and intraaortic balloon pumping (IABP) was performed 1-3 days before operation in 9 patients. Among the patients, there were 13 patients of mitral valve replacement (MVR), 7 patients of aortic valve replacement (AVR), 4 patients of tricuspid valve replacement (TVR), and 7 patients of double valve replacement (DVR). At the same time, all patients underwent ventricular or atrial volume reduction operation, including 19 patients of left atrial partial excision or plication, 7 patients of partial left ventricular excision, 5 patients of left atrial and left ventricular volume reduction operation, 21 patients of partial right atrial excision, and 3 patients of partial right ventricular excision. Besides, there were 5 patients of De Vega plasty, 14 patients of annuloplasty and3 patients of coronary artery bypass grafting (CABG). The echocardiogram was used to observe the change of heart function, atrium and ventricular in patients on postoperative and follow -up period. Results After surgery, one patient died of low cardiac output syndrome, and one other patient gave -up because of incision and mediastinum infection after reoperation for hemorrhage. Twentynine patients were followed -up for 3 to 12 months with 1 case lost. During the follow- -up, 3 patients died, of whom 2 died of deterioration of heart function and 1 died of sudden stroke. In the 12th month during the follow -up, heart function of all other 25 patients showed obvious improvements with 12 classⅠ, 7 classⅡ, 3 classⅢ and 3 classⅣ heart function according to NYHA classification. At the end of the follow -up, ejection fraction (5400%±800% vs. 2500%±300%) and cardiac index [3.30±0.50 L/(min·m2) vs. 1.10±0.30 L/(min·m2)] were significantly higher than those before operation (P<0.05), whereas left ventricular end diastolic diameter (5200±1000 mm vs. 9500±1200 mm) and left atrial diameter (3900±800 mm vs. 7000±1200 mm) both decreased significantly than those before operation (P<0.05). Conclusion Cardiac remodeling operation for endstage cardiac valve disease after active adjustment and preparation can achieve similar results to operation for severe valve diseases, providing a new choice for endstage heart disease.

    Release date:2016-08-30 05:56 Export PDF Favorites Scan
  • Equivalent modeling and evaluation of molars using point-contact higher kinematic pair based on occlusal dynamic analysis

    As a representative part of the oral system and masticatory robot system, the modeling method of the dental model is an important factor influencing the accuracy of the multi-body dynamic model. Taking the right first molars of the masticatory robot as the research object, an equivalent model, point-contact higher kinematic pair composed of v-shaped surface and sphere surface, was proposed. Firstly, the finite element method was used to analyze the occlusal dynamics of the original model in three static contact cases (intrusive contact, centric occlusion, and extrusive contact) and one dynamic chewing case, and the expected bite force was obtained. Secondly, the Hertz contact model was adopted to establish the analytical expression of the bite force of the equivalent model in three static contact cases. The normal vectors and contact stiffness in the expression were designed according to the expected bite force. Finally, the bite force performance of the equivalent model in three static contact cases and one dynamic chewing case was evaluated. The results showed that the equivalent model could achieve the equivalent bite force of 8 expected items in the static contact cases. Meanwhile, the bite force in the early and late stages of the dynamic chewing case coincides well with the original model. In the middle stage, a certain degree of impact is introduced, but it can be weakened by subsequent trajectory planning. The equivalent modeling scheme of the dental model proposed in this paper further improves the accuracy of the dynamic model of the multi-body system. It provides a new idea for the dynamic modeling of other complex human contacts.

    Release date:2020-10-20 05:56 Export PDF Favorites Scan
  • The Effect of Smooth Muscle Cell Transplantation on MyocardialMMP2, MMP9 and TIMP3 Content One Week after Myocardial Infarction

    Objective To evaluate the effect of smooth muscle cell transplantation on myocardial interstitial reconstruction shortly after myocardial infarction. Methods A total of 48 female Wister rats were randomly divided into two groups with the random number table, the control group (n=24) and the smooth muscle cell transplantation group (n=24). The left coronary artery was ligated to set up the myocardial infarction animal model. An amount of 05 ml phosphate buffered saline(PBS) containing 1×106 smooth muscle cells or 0.5 ml PBS without cells was injected into the injured myocardium immediately. By immunoblot and reverse transcriptionolymerase china reaction (RT-PCR), we observed the amount of protein and mRNA of matrix metalloproteinase2(MMP-2), matrix metalloproteinase-9(MMP-9) and tissue inhibitor of metalloprotease-3 (TIMP-3) in the myocardium of the rats. Results The transplanted smooth muscle cells survived well. Compared with the control group, myocardial TIMP3 mRNA (1.06±0.22 vs. 0.81±0.19, t=-2.358, P=0.033) and protein content (3.33±0.53 vs. 1.63±0.47, t=-6.802, Plt;0.001) were significantly increased in the transplantation group. Myocardial MMP-2, MMP-9 mRNA (0.49±0.12 vs. 1.16±0.18, t=8.453, Plt;0.001; 0.45±0.12 vs. 0.80±0.11, t=5.884, Plt;0.001) and protein content (3.98±1.08 vs. 6.05±0.91, t=4.139, P=0.001; 0.39±0.14 vs. 0.57±0.17, t=2.409, P=0.031) [CM(1585mm]were significantly reduced in the transplantation group compared with the control group. Conclusion transplanted smooth muscle cells can survive well in the infarction myocardium and can increase the amount of myocardial TIMP-3 mRNA and protein content and reduce myocardial MMP-2, MMP-9 mRNA and protein content, which is an effective way to prevent harmful cardiac remodeling.

    Release date:2016-08-30 06:02 Export PDF Favorites Scan
  • Effects of Bone Marrow Mononuclear Cells Implantation on Morphology, Structure, and Ventricular Function ofInfarct Heart in Dogs

    Abstract:  Objective To observe the changes in morphology, structure, and ventricular function of infarct heart after bone marrow mononuclear cells (BMMNC) implantation.  Methods Twenty-four dogs were divided into four groups with random number table, acute myocardial infarction (AM I) control group , AM I-BMMNC group , old myocardial infarct ion (OMI) control group and OM I-BMMNC group , 6 dogs each group. Autologous BMMNC were injected into infarct and peri-infarct myocardium fo r transplantation in AM I-BMMNC group and OM I-BMMNC group. The same volume of no-cells phosphate buffered solution (PBS) was injected into the myocardium in AM Icontrol group and OM I-control group. Before and at six weeks of cell t ransplantation, ult rasonic cardiography (UCG) were performed to observe the change of heart morphology and function, then the heart was harvested for morphological and histological study.  Results U CG showed that left ventricular end diastolic dimension (LV EDD) , left ventricular end diastolic volume (LVEDV ) , the thickness of left ventricular postwall (LVPW ) in AM I-BMMNC group were significantly less than those in AM I-control group (32. 5±5. 1mm vs. 36. 6±3. 4mm , 46. 7±12. 1m l vs. 57. 5±10. 1m l, 6. 2±0. 6mm vs. 6. 9±0. 9mm; P lt; 0. 05). LVEDD, LVEDV , LVPW in OM I-BMMNC group were significantly less than those in OM I-control group (32. 8±4. 2 mm vs. 36. 8±4. 4mm , 48. 2±12. 9m l vs. 60.6±16.5m l, 7. 0±0. 4mm vs. 7. 3±0. 5mm; P lt; 0. 05). The value of eject fraction (EF) in OM I-BMMNC group were significantly higher than that in OM I-control group (53. 3% ±10. 3% vs. 44. 7%±10. 1% ). Compared with their control group in morphological measurement, the increase of infarct region thickness (7. 0 ± 1. 9mm vs. 5. 0 ±2.0mm , 6.0±0. 6mm vs. 4. 0±0. 5mm; P lt; 0. 05) and the reduction of infarct region length (25. 5±5. 2mm vs. 32. 1±612mm , 33. 6±5. 5mm vs. 39. 0±3. 2mm , P lt; 0. 05) were observed after transplantation in AM I-BMMNC group and OM I-BMMNC group, no ventricular aneurysm was found in AM I-BMMNC group, and the ratio between long axis and minor axis circumference of left ventricle increased in OM I-BMMNC group (0. 581±0. 013 vs. 0. 566±0.015; P lt; 0. 05). Both in AM I-BMMNC group and OM I-BMMNC group, fluorescence expressed in transplantation region was observed, the morphology of most nuclei with fluorescencew as irregular, and the differentiated cardiocyte with fluorescence was not found in myocardium after transplantation. The histological examination showed more neovascularization after transp lantation both in AMI and in OM I, and significant lymphocyte infiltration in AM I-BMMNC group.  Conclusion  BMMNC implantation into infarct myocardium both in AMI and OMI have a beneficial effect, which can attenuate deleterious ventricular remodeling in morphology and st ructure, and improve neovascularization in histology, and improve the heart function.

    Release date:2016-08-30 06:08 Export PDF Favorites Scan
  • Effects of βreceptor Blocker on Intraventricular Pressure Gradient after Aortic Valve Replacement

    Abstract: Objective To investigate the effects of βreceptor 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. Thirtytwo 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 βreceptor blocker (Metoprolol, 6.2525.00 mg once, twice daily). The rest 20 patients in the control group had no βreceptor 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 endsystolic 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, P0.001), 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. 

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