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OBJECTIVE@#To investigate the effect of orthodontic traction on the microstructure of dental enamel.@*METHODS@#Forty-eight isolated premolars were randomly divided into 6 groups (=8), including Group A (blank control group), in which the teeth were bonded with the orthodontic brackets without any loading force; Groups B1, B2, and B3 where the teeth were bonded with the orthodontic brackets using clinical adhesives and loaded with 50 g force for 6 months, 200 g force for 6 months, and 200 g force for 1 month, respectively; and Groups C1 and C2, where the teeth were bonded with straight wire brackets using light curing bonding and chemical curing bonding techniques, respectively. All the teeth were embedded with non-decalcified epoxy resin. Scanning electron microscope (SEM), atomic force microscope (AFM), and energy spectrometer (EDS) were used to analyze interface morphology and elemental composition of the teeth sliced with a hard tissue microtome.@*RESULTS@#Compared with those in Group A, the teeth in the other 5 groups showed increased adhesive residue index with microcracks and void structures on the enamel surface under SEM; AFM revealed microcracks on the enamel surface with angles to the grinding direction. A larger loading force on the bracket resulted in more microcracks on the enamel interface. The interface roughness differed significantly between Groups A and C2, and the peak-to-valley distance differed significantly between Groups A, C, and C2.@*CONCLUSIONS@#Orthodontic traction can cause changes in the microstructure of normal dental enamel.
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Dental Enamel , Materials Testing , Orthodontic Brackets , Resin Cements , Surface Properties , TractionABSTRACT
Objective To investigate the change of adiponectin (AD),tumor necrosis factor-alpha (TNF-α) and S100 levels in serum elderly patients with rheumatoid arthritis and cerebral infarct in order to evaluate the therapeutic effect of dioscornin.Methods One hundred patients with rheumatoid arthritis and cerebral infarct were selected as our subjects,who were hospitalized in the Department of Neurology of Recovery Changzhi Municipal People's Hospital and the Department of Internal Medicine of the Affiliated Hospital of Shaoxing Medical College,between 2006 September and 2010 September.All subjects (male 55,female 45,average age of 57 years old) were randomly divided into regular and dioscomin groups,50 for per group.Patients in regular group were treated with routine therapy and patients in dioscornin groups were treated with dioscornin 80mg,three daily plus regular treatment drug.Meanwhile 40 middle patients with single rheumatoid arthritis subjects were severed as controls.The changes of BMI,fasting plasma glucose,lipid factors,insulin sensitivity index (ISI),serum adiponectin,TNF-α and serum S100B were determined at treatment before and 6 months after treatments.Results The level of TNF-α,serum S100 in ERA patients were significantly higher andAdiponectin significantly lower than that of the control group,(TNF-α:[(89.0 ± 25.3) ng/L,(88.0 ± 24.2)ng/L vs(74.0 ±21.0) ng/L,F =3.292,P ＜0.05],[S100B:(0.102 ±0.051) μg/L,(0.101 ±0.045) μg/L vs(0.092 ± 0.031) μg/L,F =2.792,P ＜ 0.05],and AD and BMI were lower [AD:(7.2 ± 1.4) μg/L,(7.3 ±1.4) μg/L vs (18.1 ± 3.5) μg/L,F =17.057,P ＜ 0.01],[BMI:(18.9 ± 2.4) kg/m2,(19.0 ± 1.9) kg/m2 vs (21.8 ± 1.8) kg/m2,F =6.147,P ＜ 0.01].There was a negative correlation between adiponect and TNF-α,S100B (r =-0.46,-0.52,P ＜ 0.01) and positive correlation between adiponect and BMI (r =0.44,P ＜0.01).The adiponectin level was significantly increased in patients for six months after dioscornin treatment than that of control group.[AD:(12.2±2.9) μg/L,(7.8 ±1.8) μg/L vs (18.0 ±4.3) μg/L,F=6.480,P＜0.01].The level of TNF-α and S100B significantly decreased than that of the control group,TNF-α:[(72.0 ±21.0) ng/L,(82.0±23.0)ng/L vs (68.0 ±20.0) ng/L,F =3.065,P ＜0.05],[S100B:(0.092 ±0.021)μg/L,(0.099 ±0.031) μg/L vs (0.091 ±0.029) μg/L,F=3.030,P＜0.05].Conclusion Dioscornin could ameliorate the prognosis through decreasing the levels of TNF-α and S100B,and increasing adiponectin level in patients with rheumatoid arthritis and cerebral infarct.
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Objective To investigate the effects of different fine particulate matter (PM2.5) components (water-soluble, organic, water-soluble+organic) in vivo on the NOS/NO system in the endothelial cells from rat thoracic aortas. Methods Three PM2.5 components were used to inject by vein in rat tail. ELISA and immunohistochemical technique were used to examine the change of NOS/NO system in the blood-serum and the endothelial cells from rat thoracic aorta. Results Compared with control group, three PM2.5 components increased NO level of rat blood-serum [control, (38.00±5.40) μmol/L; water-soluble group, (44.66±16.59) μmol/L, t =3.58, P0.05). Three components decreased the expression of eNOS protein in the endothelial cells from rat thoracic aorta(control, 164.68±4.80; water-soluble group, 185.43±5.63, t =4.26, P <0.05; organic groups, 194.07±9.77, t =5.26, P <0.05; Mixtural component group, 209.24±15.43, t =43.19, P <0.01), increased the expression of iNOS protein (control, 160.17±5.79; water-soluble group, 134.78±8.22, t =5.21, P <0.05; organic groups, 134.78±8.22, t =5.98, P <0.05; Mixtural component group, 81.62 ±10.59, t =34.98, P <0.01) in the endothelial cells from rat thoracic aortas.Conclusion Three components of PM2.5 induced the dysfunction of endothelial cells and disorder of NOS/NO system in the endothelial cells.
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Objective Recent studies reveal important roles of platelet P-seleetin on progression of atherosclerosis.In the present study,we examine the relation between Platelet P-selectin expression and severity of acute coronary syndromes.Methods One hundredand eighty-four consecutive patients with proven or clinically suspected acute coronary syndromes(ACS)were enrolled in the study.Level of P-selectin expression was determined bv flow cytometry.Platelet P-selectin level was expressed as the percentage of P-selectin positive platelet.Results The level of P-selectin was higher in patients with a single diseased coronary artery or multiplediseased arteries compared to thOSe with normal coronary arteries.P-selectin expression was significantly and positively correlatedwith angiographic Gensini score(r=0.323,P=0.029).Multiple regression analyses showed that the association of the percentage of P-selectin-positive platelets with ACS was independent of other clinical factors. Conclusions Platelet P-selectin is associated withseverity of acute coronary syndromes in patients with acute coronary syndromes.
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Aim To observe the effects of pituitrin ad- ministrated intravenously on electrocardiogram (ECG), and the effects of taurine on the ECG changes induced by pituitrin in conscious unrestrained rats. Methods ECG(leadⅡ)was recorded telemetrically and analyzed with Data Science International (DSI, USA); the changes of the ECG T wave and the heart rate at different times after the intravenous(iv) injection of pituitrin with or without intraperitoneal (ip) pre-administration of taurine were observed and calculated. Results ① Pituitrin 0.25～4.0 U?kg -1 dose-dependently elevated the ECG T wave; the T wave values were increased 0.75～3.42 times over the values before pituitrin, and the maximal effect appeared at 15 s after the injection. ② TAU 100, 200 or 400 mg?kg -1,injected intraperitoneally 30 min before the pituitrin, inhibited the T wave elevation and heart rate decrease induced by intravenous injection of pituitrin; compared with NS+pituitrin group, T wave elevation(mV) was decreased from 1.77?0.165 to 1.60?0.13(P
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AIM To study the effects of Phe-Met-Arg-Phe-NH2 (FMRFa) on Na+/Ca2+ exchange and its specificity for Na+/Ca2+ exchange in rat ventricular myocytes. METHODS Na+/Ca2+ exchange current and other currents of ion channels were measured using whole cell voltage clamp techniques. RESULTS A dose-related inhibition of tetrapeptide FMRFa on Na+/Ca2+ exchange was observed in rat ventricular myocytes. Inward and outward INa+/Ca2+ were inhibited by 60.1% and 56.5%, respectively, at highest concentration (100 μmol*L-1) and its IC50 were 20 μmol*L-1 and 34 μmol*L-1 in inward and outward INa+/Ca2+, respectively. Inward and outward INa+/Ca2+ were inhibited 38.7% and 34.9%, respectively, at FMRFa 5 μmol*L-1. FMRFa 5 μmol*L-1 and 20 μmol*L-1 did not affect L-type calcium current, sodium current, transient outward current and inward rectifier potassium current. CONCLUSION These data indicate that FMRFa is a specific inhibitor of Na+/Ca2+ exchange in intact rat ventricular myocytes.