Impact of catheter-tissue contact force on lesion size during right ventricular outflow tract ablation in a swine model / 中华医学杂志(英文版)

BACKGROUND@#The catheter-tissue contact force (CF) is one of the significant determinants of lesion size and thus has a considerable impact on the effectiveness of ablation procedures. This study aimed to evaluate the impact of CF on the lesion size during right ventricular outflow tract (RVOT) ablation in a swine model.@*METHODS@#Twelve Guangxi Bama miniature male pigs weighing 40 to 50 kg were studied. After general anesthesia, a ThermoCool SmartTouch contact-sensing ablation catheter was introduced to the RVOT via the femoral vein under the guidance of the CARTO 3 system. The local ventricular voltage amplitude and impedance were measured using different CF levels. We randomly divided the animals into the following four groups according to the different CF levels: group A (3-9 g); group B (10-19 g); group C (20-29 g); and group D (30-39 g). Radiofrequency ablations were performed at three points in the free wall and septum of the RVOT in power control mode at 30 W for 30 s while maintaining the saline irrigation rate at 17 mL/min. At the end of the procedures, the maximum depth, surface diameter, and lesion volume were measured and recorded. A linear regression analysis was performed to determine the relationship between continuous variables.@*RESULTS@#A total of 72 ablation lesions were created in the RVOT of the 12 Bama pigs. The maximum depth, surface diameter, and volume of the lesions measured were well correlated with the CF (free wall: β = 0.105, β = 0.162, β = 3.355, respectively, P < 0.001; septum: β = 0.093, β = 0.150, β = 3.712, respectively, P < 0.001). The regional ventricular bipolar voltage amplitude, unipolar voltage amplitude, and impedance were weakly positively associated with the CF (β = 0.065, β = 0.125, and β = 1.054, respectively, P < 0.001). There was a significant difference in the incidence of steam pops among groups A, B, C, and D (free wall: F = 7.3, P = 0.032; septum: F = 10.5, P = 0.009); and steam pops occurred only when the CF exceeded 20 g. Trans-mural lesions were observed when the CF exceeded 10 g in the free wall, while the lesions in the septum were non-trans-mural even though the CF reached 30 g.@*CONCLUSIONS@#CF seems to be a leading predictive factor for the size of formed lesions in RVOT ablation. Maintaining the CF value between 3 and 10 g may be reasonable and effective for creating the necessary lesion size and reducing the risk of complications, such as steam pops and perforations.

Therapeutic effect of L‐carnitine combined cyclic adenosine monophosphate and its influence on serum levels of IFN‐γ and IL‐4 in patients with viral myocarditis／ / 心血管康复医学杂志

To observe therapeutic effect of L‐carnitine combined cyclic adenosine monophosphate and its influence on serum levels of IFN‐γ and IL‐4 in patients with viral myocarditis .Methods : A total of 132 VMC pa‐tients treated in our hospital from 2017 to 2018 were randomly and equally divided into L‐carnitine group and com‐bined treatment group (received cAMP based on L‐carnitine group ) , both groups were treated for two weeks .Pe‐ripheral serum levels of IFN‐γ , IL‐4 , cardiac troponin T (cTnT) and creatine kinase isoenzyme MB (CK‐MB) be‐fore and two weeks after treatment , therapeutic effect and incidence of adverse drug reactions were observed and compared between two groups .Results : Compared with before treatment , there was significant rise in serum IL‐4 level , and significant reductions in serum levels of IFN‐γ , cTnT and CK‐MB in two groups after two‐week treat‐ment , P＝0. 001 all ;compared with L‐carnitine group , there was significant rise in serum IL‐4 level [ (47. 43 ± 9.17) ng／ml vs.(55. 38 ± 10.23 ) ng／ml] , and significant reductions in serum levels of IFN‐γ [ (65.22 ± 11.82 ) ng／ml vs .(52.18 ± 10.06) ng／ml] , cTnT [ (0. 37 ± 0.09) ng／ml vs.(0.18 ± 0.03) ng／ml] and CK‐MB [ (28.56 ± 5. 34) U／L vs.(16. 22 ± 3. 47) U／L] in combined treatment group , P＝0.001 all.Total effective rate of com‐bined treatment group was significantly higher than that of L‐carnitine group (92.4% vs.80.3%) , P＝ 0.042. There was no significant difference in incidence rate of adverse drug reactions between two groups , P＝0. 784. Con‐clusion : L‐carnitine combined cAMP can significantly reduce peripheral serum IFN‐γ level and increase IL‐4 level , regulate Th1／Th2 imbalance with significant therapeutic effect in VMC patients .And its safety is good .

Effect of vascular endothelial growth factor small interfering RNA (siRNA) on retinal microvascular endothelial cells under hypoxia condition in vitro / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore VEGF siRNA's effect on the immature fetal retinal microvascular endothelial cells in vitro.</p><p><b>METHOD</b>The fresh retinal micrangium was primarily cultured to obtain microvascular endothelial cells. CoCl2 was used to simulate oxygen-deficient conditions. siRNA directed against human VEGF was designed and chemically synthesized. There were 3 groups in our experiment: VEGF siRNA group, hypoxia control group, and negative siRNA control group. The fetal retinal micrangium vascular endothelial cells were transfected by using liposome. The expression levels of VEGF mRNA and protein were evaluated by RT-PCR and Western blotting 24, 48, 72 h after transfection, cell proliferation was evaluated by MTT method.</p><p><b>RESULT</b>The expression levels of VEGF mRNA decreased by 21.05%, 79.67%, and 90.48% 24 h, 48 h, and 72 h after transfection as compared to those in hypoxia control group, the expression level of VEGF protein had decreased by 14.58%, 66.97%, and 81.61% as compared to those in hypoxia control group. The siRNA could decrease cell proliferation under hypoxia too, the multiplication rate after 12, 24, 48, and 72 h decreased by 15.0%, 42.9%, 78.3% and 65.9%.</p><p><b>CONCLUSION</b>VEGF siRNA could down-regulate the expression of VEGF in immature fetal retinal microvascular endothelial cells and suppressed cell proliferation. Application of siRNA to inhibit expression of VEGF may be a hopeful way to prevent and cure ROP.</p>

The Analysis of an Inquiry in Grouping Teaching among Medical Students——the Research of Grouping Teaching Model,Students Inquiry / 中华医学教育探索杂志

By inquiring the medical students under the background of grouping teaching between the mainland students and the oversea Chinese students,we have got something about their attitude toward the credit system.The result will help us to improve the teaching renovation in medical education.The questionnaire including implementing of credit system,standard credit system, grouping teaching,curriculum,tutor system of the undergraduates,the administration of education,and so on.Then we analyze and get the result.