ABSTRACT
Background Q-value is used to express the asphricity of the anterior corneal surface.As a optical surface,the optial morphology of cornea is composed of a series of tangential sections that cut-off through the optical axial.Therefore,tangential section could represent the true optical morphology of the corneal surface,and Q-value calculation by tangential radius can better represent the asphericity.Objective This study was to calculate Q-value of meridian section of the anterior corneal surface by tangential radius of the tangential topography and analyze the corneal asphericity in horizontal interval.Methods Ninety right eyes of 90 myopia subjects aged 16-30years and with mean spherical equivalent of (-5.45 ± 2.75) D received corneal topography examination using Orbscan Ⅱ system.The subjects were assigned to low myopia group,moderate myopia group and high myopia group based on their diopter and 30 eyes for each group.The tangential curvatures on meridian section at a 0.1 mm interval from apex to periphery of the anterior surface were accepted and the Q value of the semimeridian section was calculated by linear regression mathematical formulas of the tangential radius.Mydriatic optometry,intraocular pressure,keratometer and fundus examinations were performed on the subjects.Written informed consent was obtained from each subject before any medical examination.Results The coefficients of determination in all the semimeridians were over 0.5.The average calculated Q-values in the nasal and temporal horizontal interval were -0.32±0.11 and-0.30±0.12,with a significant difference between them (t =2.009,P＜0.05).The vertex radius of curvature was (7.78±0.27)mm and (7.72±0.25)mm respectively in the nasal and temporal horizontal interval,showing a significant difference(t=-1.016,P＞0.05).No significant difference was seen in Q values of both nasal and temporal areas among three myopic groups (nasal:F =0.192,P =0.825 ; temporal:F =0.912,P =0.406).The average Q value of the nasal and temporal principal meridian was-0.33±0.14 and-0.30±0.13 respectively,and the r0 was 7.76±0.30 and 7.74±0.24 respectively.A weak positive correlation was found between r0 and mean Q value of nasal meridian (r=0.320,P＜0.05),but no significant correlation was found between r0 and mean Q-value of temporal meridian (r=0.104,P＞0.05).No significant differenees were seen in the Q values between nasal meridian and nasal zone (t=0.349,P＞0.05) as well as between temporal meridian and temporal zone(t=-0.373,P＞0.05).Conclusions The study analyzes the calculated Q-value of the semimeridian section in borizontal area with myopia by linear regression mathematical formulas of tangential radius on tangential topography.The anterior surface of the cornea is proved to be prolate ellipse in shape in the subjects with myopia.
ABSTRACT
<p><b>OBJECTIVE</b>Landmark trials have demonstrated that statins can reduce the risk of coronary events. Despite the widespread use of statins in the settings of primary and secondary prevention of CHD, withdrawal of statins is a frequent problem in clinical practice. Several recent clinical studies have suggested that withdrawal of statin therapy might be associated with an increase in thrombotic vascular events and the onset of acute coronary syndromes. However, the effects of discontinuing of statins treatment on endothelial function and underlying mechanism are unknown. Objectives We investigated the effects after withdrawal of simvastatin on brachial artery endothelial function in patients unreached cholesterol target with coronary heart disease (CHD) or CHD risk factors.</p><p><b>METHODS</b>We included 33 patients with established CHD or CHD risk factors, whose serum cholesterol did not achieve NCEP target level. They were administered simvastatin (20 mg) for 4 weeks. Endothelial dependent flow-mediated vasodilation (FMD) was assessed in the brachial artery using high-resolution ultrasound at baseline, after 4 weeks of simvastatin and after termination of therapy 1 week. We evaluated fasting serum lipid profiles and vasoactive substances simultaneously, included nitric oxide (NO), endothelin (ET), 6-keto-PGF1(alpha) and thromboxane B(2) (TXB(2)), which were measured as plasma prostacyclin and TXA(2) respectively.</p><p><b>RESULTS</b>Simvastatin treatment reduced low density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) levels and improved endothelial-dependent vasodilation in patients after 4 weeks. Withdrawal of simvastatin, however, FMD showed a significant reduction [(4.82 +/- 0.71)% vs (11.51 +/- 0.87)%, P < 0.01], that remained in low level after 1 week, and the FMD were even lower than the baseline values [(4.82 +/- 0.71)% vs (5.89 +/- 0.65)%, P < 0.01]. After terminating simvastatin treatment, serum NO and plasma 6-keto-PGF1(alpha) levels decreased, as well as plasma ET and serum LDL-C levels increased. But there was no significant difference between plasma TXB(2) levels before and after withdrawal of simvastatin (P > 0.05). Overall, there were significant positive correlations between withdrawal-induced changes in FMD and serum NO level (r = 0.674, P = 0.004), whereas no correlations were shown between the changes in FMD and serum LDL-C level (r = -0.414, P = 0.083).</p><p><b>CONCLUSIONS</b>Abrupt withdrawal of simvastatin therapy resulted in the significant adverse impact on brachial artery endothelial function in patients unreached cholesterol target with CHD or CHD risk factors. Termination of therapy may suppress endothelial NO production and impair endothelial function that is independent of lipid-lowering effect.</p>
Subject(s)
Aged , Female , Humans , Male , Middle Aged , Brachial Artery , Cholesterol, LDL , Blood , Coronary Disease , Drug Therapy , Endothelium, Vascular , Hypolipidemic Agents , Nitric Oxide , Blood , Risk Factors , Simvastatin , VasodilationABSTRACT
<p><b>OBJECTIVE</b>To find a method without corticosteroids, aspirin or heparin for treatment of anticardiolipin antibody-positive early recurrent spontaneous abortion (AARSA).</p><p><b>METHODS</b>Twenty-three patients of AARSA in the treated group were treated with Chinese herbal medicine (CHM) plus human chorionic gonadotropin and progesterone, and 18 patiens in the control group were treated with multi-vitamin only. The change of anticardiolipin antibody was determined by enzyme linked immunoabsorbent assay (ELISA).</p><p><b>RESULTS</b>After treatment, anticardiolipin antibody negative converted in 20 cases (86.9%) of the treated group. The cure rate of abortion in the treated group was 82.6% (19/23), which was raised to 95% (19/20) in those patients with antibody negative conversion, while in the control group, it was 16.7% (3/18) merely, comparison between the two groups in cure rate showed significant difference (P < 0.01).</p><p><b>CONCLUSION</b>CHM plus human chorionic gonadotropin and progesterone could cure AARSA effectively.</p>