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In order to stimulate students' interest in orthodontics and develop their competency in self-directed learning,innovation and practice,we introduced "maker education" into the orthodontics course for undergraduate.In the early stage,the teaching materials were organized based on fragmentation of learning,and the "maker group" is the basic unit.In class,the topics were discussed in the form of flipped classroom.Finally,a series of orthodontic experiments were carried out.This article can provide new ways to improve the quality of orthodontics education.
ABSTRACT
<p><b>BACKGROUND</b>Erythropoietin (EPO) and granulocyte colony-stimulating factor (G-CSF) are both potential novel therapeutics for use after myocardial infarction (MI). However, their underlying mechanisms remain unclear and the efficacy of monotherapy with EPO or G-CSF is also controversial. Therefore, we investigated the effects of combined treatment with EPO and G-CSF on neovascularization and cardiac function in post-infarction rats and explored the potential mechanisms.</p><p><b>METHODS</b>Four groups of rats were used: control (saline injection after MI, i.h.), EPO (a single dose of 5 000 IU/kg after MI, i.h.), G-CSF (a dose of 50 µg× kg(-1)× d(-1) for 5 days after MI, i.h.), and both EPO and G-CSF (EPO+G-CSF, using the same regiment as above). Cardiac function was assessed by echocardiography before and 1 day, 7 days, 14 days and 21 days after MI. CD34(+)/Flk-1(+) cells in the peripheral blood were evaluated by flow cytometry before and 3 days, 5 days and 7 days after MI. The infarct area and angiogenesis in the peri-infarct area were analyzed. The mRNA and protein expression of vascular endothelial growth factor (VEGF) and stromal-derived factor-1a (SDF-1α) in the peri-infarct area were detected by real-time quantitative RT-PCR and Western blotting.</p><p><b>RESULTS</b>Compared with the control and monotherapy groups, the EPO+G-CSF group had significantly increased CD34(+)/Flk-1(+) endothelial progenitor cells (EPCs) in the peripheral blood (P < 0.05), up-regulated VEGF and SDF-1α levels in the peri-infarct region (P < 0.05), enhanced capillary density (P < 0.05), reduced infarct size (P < 0.05) and improved cardiac structure and function (P < 0.05). G-CSF alone did not dramatically increase EPCs in the peripheral blood, enhance capillary density in the peri-infarct area or reduce infarct size compared with the control group.</p><p><b>CONCLUSIONS</b>Combined treatment with EPO and G-CSF increased EPCs mobilization, up-regulated VEGF and SDF-1α levels in the post-infarction microenvironment, subsequently enhanced neovascularization in the peri-infarct region and reduced infarct size. All factors contributed to its beneficial effects on cardiac function in post-infarction rats.</p>
Subject(s)
Animals , Male , Rats , Blotting, Western , Chemokine CXCL12 , Metabolism , Echocardiography , Erythropoietin , Therapeutic Uses , Flow Cytometry , Granulocyte Colony-Stimulating Factor , Therapeutic Uses , Myocardial Infarction , Drug Therapy , Metabolism , Neovascularization, Physiologic , Rats, Sprague-DawleyABSTRACT
Objective To evaluate the feasibility and value of quantitatively assessing left ventricular systolic function in rats with myocardial infarction (MI) by myocardial contrast echocardiography (MCE) based on mathematical morphology algorithm.Methods SD rats model of MI were mede,then MCE were performed before MI and at 1,3 weeks after MI.In vitro study:based on the principle of binary morphology,segmentation of endocardium was acquired using dilation,erosion,closed operations and connected domain object tag-based.The automatic segmentation of endocardial contour was compared with the manual segmentation boundary.In vivo study:the left ventricular area was calculated using the software,and the area variation fraction (AVF),a new index of left ventricular systolic function,were acquired.The correlation between AVF and left ventricular ejection fraction (LVEF) was analyzed.The value of AVF for diagnosis for left ventricular dysfunction was evaluated by ROC curve.Results ① The cross-correlation coefficient (CCC) and percent error (PE) between automatic contours and manual boundary were more than 0.90 and less than 9％,respectively.② AVF correlated positively with LVEF (r =0.934,P ＜ 0.001).③ ROC analyses showed the area under curves for AVF diagnosing left ventricular dysfunction was 0.834.The best cutoff value was 27.5 ％ for diagnosing left ventricular dysfunction with the sensitivity of 85 ％ and specificity of 60 ％.Conclusions Left ventricular endocardium can be identificated automatically and rapidly by MCE based on mathematical morphology algorithm.AVF can assessed quantitatively left ventricular systolic function in rats with myocardial infarction.
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AIM To observe whether acute stimulation of BRL 37344, a β3-adrenergic receptor (β3-AR) agonist, has the same effects of exacerbating hemodynamics and increasing in β3-AR expression on rats with failing heart as chronic administration. METHODSRats received two doses of isoprenaline (Iso, 340 mg·kg-1, sc, with a 24-h interval) to prepare heart failure model. After 8 weeks, rats were given iv BRL 37344 0.4 nmol·kg-1·min-1 for 10 min. Hemodynamics were measured at 0, 10, 30 min, 1, 2, 3 h, 1, 2 and 7 d after BRL 37344. Levels of β-AR mRNA in myocardium were measured at 0, 1, 2 and 7 d after BRL 37344 by reverse transcription-polymerase chain reaction. RESULTSCompared with Iso group, heart rate, left ventricular end systolic pressure and +dp/dtmax were significantly higher, and left ventricular end diastolic pressure was significantly lower during 1-3 h after BRL 37344 injection in Iso+BRL group. Then, they were restored to the same level as that prior to BRL 37344 injection. Compared with normal control, the levels of β1-, β2- and β3-AR mRNA displayed no significant change in BRL group;the level of β1-AR mRNA was lower and the level of β3-AR mRNA was higher in Iso group. In Iso+BRL group, much more lower β1-AR mRNA level and much higher β3-AR mRNA level were shown on d 2 and d 7 than Iso group. CONCLUSION Acute administration of β3-AR agonist has a shorter improved hemodynamics. But it caused the same result as chronic administration in reduction of β1-AR mRNA and increment of β3-AR mRNA in failure hearts, which may aggravate the cardiac functions.
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Objective To investigate the effects of valsartan on platelet and endothelial function in atrial fibrillation dogs induced by chronic rapid atrial pacing.Methods From Sep.2001 to Jun.2003,14 dogs paced at 400 bpm in the right atrium for 6 weeks were randomly divided into control group and valsartan group.The dogs in valsartan group received valsartan(30 mg?kg~ -1 ?d~ -1 )1 week before rapid atrial pacing until pacing stop.The plasma von Willebrand factor(vWF),endothelin-1(ET-1),angiotensin Ⅱ(AngⅡ)levels and blood platelet aggregation rate were measured before and after rapid atrial pacing.Results (1)Plasma AngⅡ level elevated significantly in both groups,indicating activation of renin-angiotensin system.(2)The maximam platelet aggregation rates by four different agonists(Adenosine diphosphate,Epinephrine,Collagen,Arachidonic acid)increased significantly in control group dogs.To some extent,valsartan could inhibit platelet activation caused by chronic rapid atrial pacing.(3)There were significant elevations in the plasma levels of vWF and ET-1 in control group dogs.Valsartan could meliorate endothelial function and decrease the concentrations of vWF and ET-1.Conclusion Valsartan can inhibit platelet activation and meliorate endothelial function in chronic rapid atrial pacing dogs.