Investigation of posterior corneal curvature in CL-induced corneal swelling

Purpose

To evaluate Orbscan II measurements without contact lens (CL) removal to monitor in vivo posterior corneal curvature in CL (hypoxia)-induced corneal swelling during extended wear (EW).

Methods

Orbscan II corneal topographer was used to measure posterior corneal curvature 1 week before CL wearing and during 1 week of EW. Central corneal thickness (CCT) was also measured during the 2-week study with OCT to determine the corneal swelling percentage. High Dk (lotrafilcon A) and low Dk (etafilcon A) soft CL were randomly fitted in EW in the right and left eyes of 20 subjects with normal ocular health. Orbscan and OCT were also performed without CL removal after 3 and 7 days of wear.

Results

Low Dk lenses induced significantly higher corneal swelling (2.41 ± 2.65%), as compared to the high Dk lenses (0.17 ± 2.28%; P < 0.05 repeated measures ANOVA (Re-ANOVA and paired t-test) measures with OCT. The low Dk lens induced a significantly posterior corneal flattening compared to the high Dk lens (0.036 ± 0.06 mm versus 0.006 ± 0.04 mm; P < 0.05 Re-ANOVA and paired t-test). High repeatability for Orbscan-measured posterior best fit sphere (BFS) radii with (r² = 0.15, 95% limits of agreement (LoA) = 0.10 to −0.06) and without (r² = 0.00, 95% LoA = 0.08 to −0.08) CL removal was also observed and suggest that posterior corneal changes was not due to Orbscan variability.

Conclusions

Orbscan is a non-invasive and reproducible technique to evaluate and monitoring posterior corneal curvature in vivo in CL (hypoxia)-induced corneal swelling during EW.     

Traumatic insertion of eyelashes into corneal stroma

An unusual case of eyelashes being traumatically inserted into the corneal stroma is presented. A 75-year-old hit her right eye with her own fist, presenting with intra-corneal eyelashes. All remained entirely within the cornea, with no breach of the endothelium. They seemed to have tracked there first through the superior conjunctiva and then the superior limbus. The lashes were surgically removed, with good visual recovery. The authors present a short review of intra-ocular eyelash insertion.     

燕麦β-葡聚糖水凝胶溶胀性研究

凝胶性是燕麦β–葡聚糖的重要特性。该文研究了温度、pH和质量分数对燕麦β–葡聚糖水凝胶溶胀率的影响,并对凝胶溶胀动力学过程进行了分析。结果表明,温度越高,燕麦β–葡聚糖凝胶溶胀率越大;碱性条件下溶胀率显著增大;凝胶溶胀率随着质量分数的增大而下降。对β–葡聚糖溶胀性动力学研究表明,溶胀初期满足Fickian扩散定律,是扩散过程控制的溶胀。     

Fluorescein staining and physiological state of corneal epithelial cells

PurposeTo evaluate the physiological status of corneal epithelial cells exhibiting fluorescein staining.MethodsFluorescein staining properties of corneal epithelial cells under normal and stressed conditions were studied using cell-culture (human corneal limbal epithelial cells – HCLE) and organ-culture (rabbit) models. Stress stimuli comprised exposure to hypotonicity, hypertonicity, preservatives, scratch, and alkaline wounding. In addition to fluorescein, cells were stained with Hoechst-33342 (HO), Propidium-iodide (PI), and Annexin-V (AN-V) to identify live, dead and apoptotic cells. Clinical-slit-lamp and fluorescence confocal-microscopic (FCM) observations were performed. FCM images were quantified for fluorescence intensity using Image-J software.ResultsHealthy HCLE cells uniformly took up fluorescein to a moderate degree with a mean grey value of 62 ± 24 (mean ± SD) on a scale of 0–256 (no unit). Fluorescence levels similar to those observed prior to stress were associated with healthy cells. Apoptotic cells showed the highest fluorescence (138 ± 38). Dead cells showed minimal fluorescence (23 ± 7) that was similar to the background (20 ± 11, p > 0.05). Observations in whole rabbit eyes were in general agreement with these cell culture findings.ConclusionsThe clinical observation of corneal staining with fluorescein suggests the presence of epithelial cells that are undergoing apoptosis but does not indicate dead cells. Under in vitro or ex vivo conditions, healthy cells took up fluorescein at levels that were lower than those of apoptotic cells and thus, are not likely to be perceived as exhibiting staining during clinical observation. Sodium fluorescein may be considered as a probe for apoptotic epithelial cells.     

pH对含天然多聚糖基生物凝胶膨胀特性的影响

研究了pH对含天然多聚糖基生物凝胶结构及响应特性的影响.结果表明,含天然多聚糖基的生物凝胶在pH=7时,膨胀率达到最大;在pH=4～7时,通过调节pH可使接枝胶的膨胀和收缩反复进行多次.     

大豆活性成分及其生理功能

<正> 大豆是人类的重要食物资源,它不仅富含营养物质,还含有大豆蛋白、大豆多肽、大豆异黄酮、大豆皂苷、大豆磷脂、大豆低聚糖、大豆植酸及大豆膳食纤维等多种具有独特生理功能的活性成分。近年来,许多研究工作表明,大豆活性成分在保健食品和医药等领域有着极高的潜在应用价值。基于大豆的保健和药用价值,对大豆的综合     

Proteomic profiling of human corneal stroma from long-term contact lens wearers reveals activation of inflammatory responses

PurposeTo investigate the association between proteomic changes and potential pathogenesis in the human cornea with respect to the duration of wearing soft contact lenses (SCLs).MethodsA total of 96 corneal stroma samples, obtained via small incision lenticule extraction (SMILE), were equally grouped according to the duration of wearing SCL: 0Y, did not wear SCL; 5Y, wore SCL for<5 years; 5–10Y, wore SCL for 5–10 years; O10Y, wore SCL for>10 years. Liquid chromatography–tandem mass spectrometry was used to identify and quantify protein profiles in the corneal stroma. Expression levels of CO1A1, CO4A1, NFKB1, and IL6RB were determined using western blot and immunohistochemistry analysis.ResultsThis study quantified a total of 5,668 proteins across samples and identified 2,379 differentially expressed proteins (DEPs) with significantly increased abundance in the three SCL-wearing groups compared with that in the non-SCL-wearing group. Compared with those in the 0Y group, the molecular functions of DEPs in the 5Y, 5–10Y, and O10Y groups were mainly related to translation regulator activity, antigen binding, peptidase inhibitor activity, participation in extracellular matrix (ECM) production, complement activation, and inflammatory responses. Pathway enrichment analysis of DEPs showed that the sphingolipid, phosphatidylinositol 3-kinase-protein kinase B, and hypoxia-inducible factor-1 signaling pathways were activated in the human corneal stroma after long-term SCL use.ConclusionsInflammation-related proteomic components in human corneal stroma increased after long-term use of SCL and may act as an essential factor in the molecular pathogenesis of corneal stroma damage.     

Effect of cross-linking on the physicochemical and physiological properties of corn starch

Corn starch was chemically modified by cross-linking with STMP/STPP (99:1. w/w) and the physicochemical and physiological properties (in vitro and in vivo) of the cross-linked corn starch were investigated as a function of the degree of cross-linking. Cross-linking decreased the solubility, swelling factor, and paste clarity of corn starch. While the swelling factor was highly correlated with the degree of cross-linking (R² = 0.878), the X-ray diffraction patterns did not show any significant alteration in the crystallinity of corn starch. It was shown by SEM measurement that a black zone was observed on the surface of crossed-linked starch granules, which did not occur with native starch. When mice were fed the diets containing the corn starch with low (CLCS-5) and high (CLCS-12) degree of cross-linking (51.3 and 99.1%, respectively), significant effects on the final body weight, weight gain as well as perirenal weight of the mice (p < 0.05) were observed. Also, significant decreases in total lipid, triglyceride, and total cholesterol concentrations in serum were detected in CLCS-5 and CLCS-12 groups (p < 0.05). While total lipid level in the liver decreased with increasing degree of cross-linking, the triglyceride level was not affected by the supplementation with both of CLCS-5 and CLCS-12 corn starch samples.     

柠檬酸钠对小鼠生理及肠道菌群的影响

研究添加剂柠檬酸钠对小鼠的生长、血清生化指标及肠道菌群的影响。小鼠随机分为空白组、低剂量组(添加量0.65%)、中剂量组(添加量2.6%)和高剂量组(添加量5.2%),分别连续膳食干预4周,于不同时间点采集各组小鼠粪便样品并记录体重、采食量等数据;试验结束后对小鼠血清生化指标和肠道菌群进行分析,结果表明:柠檬酸钠组小鼠体重均低于空白组,且高剂量组小鼠的血清高密度脂蛋白胆固醇含量显著增高(P0.05)。柠檬酸钠的添加影响了小鼠肠道微生物的beta多样性,使厚壁菌门和拟杆菌门的比例发生变化。在属水平上,柠檬酸钠高剂量组检测出了棒状杆菌属和葡萄球菌属,说明摄食高剂量的柠檬酸钠会对小鼠肠道微生态造成一定影响。     

A simple technique for measurement of corneal thickness.

Measurement of corneal thickness has potential benefit both in the fitting of contact lenses and in monitoring any pathology that could affect corneal thickness. Corneal thickness measurement is undertaken using an accessory to the biomicroscope, the optical pachometer, or by means of expensive apparatus such as the ultrasonic pachometer. There are other complex methods, such as laser Doppler interferometry, or ultrasonic rasters of the cornea. In this study, an easier and low cost method, based on the measurement of the optical section formed of the cornea by the biomicroscope illumination system, is proposed. The advantages of this new method are the simplicity of its experimental set-up which consists of a calibrated graticule in an eyepiece of the biomicroscope, the speed of the measurement which increases with practice and the low cost, due to the fact that the biomicroscope is standard equipment in the ophthalmic consulting room.     

壳聚糖-果胶钙微球的制备及其体外溶胀释放性的研究

通过将离子移变交联和聚电解质络合相结合,制备载有牛血清白蛋白的壳聚糖-果胶钙微球。以微球形态、包封率、载药量、体外溶胀度以及释放率为指标,依次考察果胶溶液的浓度、氯化钙溶液的浓度和壳聚糖溶液浓度等因素对微球质量的影响。结果表明,最佳制备工艺为:7%（w/v）的果胶溶液,3%（w/v）氯化钙溶液,pH5.5的氯化钙-壳聚糖交联溶液,0.50%（w/v）的壳聚糖溶液,5%（w/v）的BSA浓度。最终,壳聚糖-果胶钙微球的包封率高达89.68%,载量高达32.13%,释放时间显著延长,缓释效果得到明显改善。因此,壳聚糖-果胶钙微球能够有效包埋BSA并有望成为功能成分经口服肠道释放的载体。      

叶黄素(Lutein)的结构、分布、物化性质及生理功能

本文简要介绍了叶黄素的结构、分布、物化性质和生理功能。     

钛营养对烤烟生长过程中生理特性的影响

研究了不同浓度钛溶液灌根对烤烟生长过程中各种生理特性的影响.结果表明:在伸根期用适量的钛肥灌根,能增加烤烟叶片中叶绿素、类胡萝卜素含量和转化酶活性,可以促进烤烟的光合作用,有利于烟草同化产物的转化和利用,同时也能够提高烤烟叶片中SOD和POD活性,降低MDA含量,明显降低烟叶中细胞膜脂过氧化程度,提高烤烟抗衰老能力和抗逆性.上述作用,在钛肥灌根的短期内,效果尤为明显,其中富钛增效剂稀释600倍灌根效果最好.     

A machine learning-based algorithm for estimating the original corneal curvature based on corneal topography after orthokeratology

ObjectiveTo estimate the original corneal curvature after orthokeratology by applying a machine learning-based algorithm.MethodsA total of 497 right eyes of 497 patients undergoing overnight orthokeratology for myopia for more than 1 year were enrolled in this retrospective study. All patients were fitted with lenses from Paragon CRT. Corneal topography was obtained by a Sirius corneal topography system (CSO, Italy). Original flat K (K1) and original steep K (K2) were set as the targets of calculation. The importance of each variable was explored by Fisher’s criterion. Two machine learning models were established to allow adaptation to more situations. Bagging Tree, Gaussian process, support vector machine (SVM), and decision tree were used for prediction.ResultsK2 after one year of orthokeratology (K2_after) was most important in the prediction of K1 and K2. Bagging Tree performed best in both models 1 and 2 for K1 prediction (R = 0.812, RMSE = 0.855 in model 1 and R = 0.812, RMSE = 0.858 in model 2) and K2 prediction (R = 0.831, RMSE = 0.898 in model 1 and R = 0.837, RMSE = 0.888 in model 2). In model 1, the difference was 0.006 ± 1.34 D (p = 0.93) between the predictive value of K1 and the true value of K1 (K1_before) and was 0.005 ± 1.51 D(p = 0.94) between the predictive value of K2 and the true value of K2 (K2_before). In model 2, the difference was −0.056 ± 1.75 D (p = 0.59) between the predictive value of K1 and K1_before and was 0.017 ± 2.01 D(p = 0.88) between the predictive value of K2 and K2_before.ConclusionBagging Tree performed best in predicting K1 and K2. Machine learning can be applied to predict the corneal curvature for those who cannot provide the initial corneal parameters in the outpatient clinic, providing a relatively certain degree of reference for the refitting of the Ortho-k lenses.     

低聚异麦芽糖理化功能特性及生产方法研究进展

低聚异麦芽糖是由α-1,6-糖苷键结合的功能性低聚糖,具有优良的理化特性和显著的生理功能,广泛应用于医药、食品、保健品及饲料行业。文中综述了低聚异麦芽糖的理化特性和生理功能,并从酶催化、分离纯化环节探讨了低聚异麦芽糖的生产技术。