Study of trace-element metabolism during the formation of rat's cataract

A cataract in the lenses of Wistar rats was induced by injecting Na₂SeO₃ into their bodies; they exhibited various kinds of cataract between 8 and 28 days. Samples were prepared using the method of low temperature ashing. The trace-element analyses of samples of different kinds of lenses were carried out by PIXE method. From the results obtained we have studied the ratio of their concentrations relative to the control values in relation to the formation time of cataract. It was found that the metabolites, of most trace-elements in the control lenses are stable, but in various kinds of cataractous lenses they display certain changes. Elements are clearly divided into two types. Elements of the first type are S, Cl, Ca, Fe and Zn. They appear to accumulate relative to the controls, while the second type, P, K and Rb, shows deficiency. The functions of trace-element metabolism during the formation of cataract are also discussed.     

Glycation and insolubility of human lens protein.

To learn whether glycation plays a role in insolubilization or in senile cataractogenesis, the reactivity of lens protein from normal and senile cataractous lenses and individual crystallin prepared from human lens with various sugars [glucose, glucose-1-phosphate (G-1-P), glucose-6-phosphate (G-6-P) and fructose], and the insolubility of those proteins were determined. The reactivity of human lens protein to glucose was increased in a dose-dependent manner, and it was demonstrated that 17.9, 18.5 and 24 kDa proteins were susceptible to glycation with sugars. The study also showed that alpha-, beta-crystallins and high molecular weight (HMW) aggregate obtained from cataractous lens have some weak reactivity against sugars. It was demonstrated that the proteins obtained from normal lens of older age and from cataractous lenses have higher insolubilities to glucose than do normal younger ones. Measurement of glycosylated protein by affinity column chromatography revealed that cataractous lenses contained a larger amount of glycosylated protein than normal ones. These results suggest that there is an age-related increase of glycation in normal human lens protein, and that such glycation increases the amount of insolubilized protein with the effect of aging. The author also speculates that an abnormal acceleration of glycation in the human lens may induce senile cataract formation.     

石墨炉原子吸收光谱法测定不同镍环境下人眼晶状体的镍量

利用高灵敏度的石墨炉原子吸收光谱仪对来自不同镍环境和不同状态的40个人眼晶状体中的镍进行了测试。在测试中，采用了方便的HNO，消解法对样品进行预处理，通过实验比较测得普通石墨管对镍的特征质量是长寿命石墨管的4．6倍，然后用长寿命石墨管对各种样品的消解后获得的测试液进行镍的测定，由此得到每个人眼晶状体中的绦量。结果表明：正常人的透明晶状体中的镍量明显低于患有白内障人眼晶状体中的镍量；而与镍矿直接接触的白内障患者的晶状体中的镍量显著高于非直接接触镍矿白内障患者和一般白内障患者晶状体中的镍量。这种关联表明人眼晶状体中的镍元素可能是白内障的致病因素之一。     

老年性白内障晶状体中金属元素的人工神经网分析

由Ｋ、Ｎａ，Ｃａ，Ｍｇ，Ｆｅ，Ｃｕ，Ｚｎ和Ｍｎ在老年性晶状体中的含量，运用人工神经网法成功地将老年性白内障，白内障晶状体核和正常人晶状体划分为３类，同时讨论了神经网的结构（层数及每层的结点数）、初始权重等对神经网性能的影响，随机地将３０个晶状体分为训练集和测试集，其识别率及预测率均达到１００％。     

Pattern recognition study of biochemical assays for liver function

To extract discriminant information from analytical data, results from eight conventional biochemical tests of liver function and from determinations of two serum bile acids are studied by supervised pattern recognition methods. The population comprised healthy subjects and seven groups of people affected by different liver diseases. The principal components, linear discriminant, k nearest neighbours and Bayesian methods were applied. Because the prediction ability computed on the whole data set was poor, the problem was simplified by dividing the data set into three subsets, each comprising two liver diseases which were contiguous and overlapped in the hyperspace of variables. The prediction ability of the Bayesian method reached 96% at best, 75% at minimum, in the three subsets. Best performance was achieved in distinguishing between healthy subjects and those with mild liver diseases on the basis of four biochemical assays.     

DSC examinations on cataractous lens materials obtained by phacoemulsification

Modifications of lens proteins play a crucial role in the formation of cataract, which is among the leading causes of world blindness in the ageing population. Although modern cataract surgery by phacoemulsification is a very successful and safe procedure, the prevention of cataract formation would be a real breakthrough in this field of ophthalmology. The aim of our study was to analyse the thermal denaturation of the cataractous lens proteins by the method of differential scanning calorimetry (DSC), to understand cataract formation and to work on its prevention possibilities. Samples were obtained from cataract patients of different age, sex, patients with and without diabetes mellitus. Samples were obtained from lenses of mature degree and progredient degree of cataract as well. Previous DSC examinations were performed on manually extracted human cataractous lens materials, however to the best of our knowledge, this is the first study, in which DSC examinations were performed on lens materials obtained by the phacoemulsification technique, which gained acceptance world-wide in the last decade. The online version of the original article can be found at     

老年性白内障与微量元素

参阅有关老年性白内障的文献．归纳其病因有四种学说:(1)老化学说;(2)醌体学说;(3)微量元素学说;(4)中医学说．按病因学说不同．用药各异．目前治疗老年性白内障药物有滴眼剂及内服剂,其中有一种新药名为除障灵．它是根据中医学说及微量元素学说，筛选中药制成,它含有丰富的锌、硒、铜、镁等微量元素．应用除障灵治疗老年性白内障患者102例(204只眼)，观察6个月至2年，有效率达95％，开创了治疗老年性白内障的新方法．     

Investigations on inorganic elements in human lenses of normal and senile cataractous character

Some essential trace elements as copper, zinc, iron, cobalt, scandium and rubidium have been measured by neutron activation analysis in normal and different types of senile cataractous lenses.     

Integrated LC/MS and GC/MS Metabolomics Data for the Evaluation of Protection Function of Fructus Ligustri Lucidi on Mouse Liver

A comprehensive metabolomic strategy, integrating GC/MS and LC/MS data, had been developed to study the protection function of herbal medicine, Fructus Ligustri Lucidi, on mouse liver. Mouse plasma samples were analyzed by GC/MS and LC/MS in conjunction with multiblock multivariate analysis method, multiblock partial least squares discriminant analysis (MBPLS-DA), to supply more important and distinct information of metabolomic biomarkers. Then, the biological pathway analysis was carried out to help further understanding the mechanism of liver protection of Fructus Ligustri Lucidi.     

Discrimination of Ganoderma lucidum according to geographical origin with near infrared diffuse reflectance spectroscopy and pattern recognition techniques

A rapid and nondestructive near infrared (NIR) method combined with chemometrics was used to discriminate Ganoderma lucidum according to cultivation area. Raw, first, and second derivative NIR spectra were compared to develop a robust classification rule. The chemical properties of G. lucidum samples were also investigated to find out the difference between samples from six varied origins. It could be found that the amount of polysaccharides and triterpenoid saponins in G. lucidum samples was considerably different based on cultivation area. These differences make NIR spectroscopic method viable. Principal component analysis (PCA), discriminant partial least-squares (DPLS) and discriminant analysis (DA) were applied to classify the geographical origins of those samples. The results showed that excellent classification could be obtained after optimizing spectral pre-treatment. For the discriminating of samples from three different provinces, DPLS provided 100% correct classifications. Moreover, for samples from six different locations, the correct classifications of the calibration as well as the validation data set were 96.6% using the DA method after the SNV first derivative spectral pre-treatment. Overall, NIR diffuse reflectance spectroscopy using pattern recognition was shown to have significant potential as a rapid and accurate method for the identification of herbal medicines.     

Application of UHPLC Fingerprints Combined with Chemical Pattern Recognition Analysis in the Differentiation of Six Rhodiola Species

Rhodiola, especially Rhodiola crenulate and Rhodiola rosea, is an increasingly widely used traditional medicine or dietary supplement in Asian and western countries. Because of the phytochemical diversity and difference of therapeutic efficacy among Rhodiola species, it is crucial to accurately identify them. In this study, a simple and efficient method of the classification of Rhodiola crenulate, Rhodiola rosea, and their confusable species (Rhodiola serrata, Rhodiola yunnanensis, Rhodiola kirilowii and Rhodiola fastigiate) was established by UHPLC fingerprints combined with chemical pattern recognition analysis. The results showed that similarity analysis and principal component analysis (PCA) could not achieve accurate classification among the six Rhodiola species. Linear discriminant analysis (LDA) combined with stepwise feature selection exhibited effective discrimination. Seven characteristic peaks that are responsible for accurate classification were selected, and their distinguishing ability was successfully verified by partial least-squares discriminant analysis (PLS-DA) and orthogonal partial least-squares discriminant analysis (OPLS-DA), respectively. Finally, the components of these seven characteristic peaks were identified as 1-(2-Hydroxy-2-methylbutanoate) β-D-glucopyranose, 4-O-glucosyl-p-coumaric acid, salidroside, epigallocatechin, 1,2,3,4,6-pentagalloyglucose, epigallocatechin gallate, and (+)-isolarisiresinol-4′-O-β-D-glucopyranoside or (+)-isolarisiresinol-4-O-β-D-glucopyranoside, respectively. The results obtained in our study provided useful information for authenticity identification and classification of Rhodiola species.     

基于近红外光谱技术与化学计量学的绿茶无损鉴别方法研究

该文利用近红外光谱技术结合化学计量学方法开发了不同品种绿茶的无损鉴别方法。通过近红外光谱技术得到了8个品种绿茶样品的近红外光谱,比较了单一以及优化组合光谱预处理方法对光谱的影响,利用无监督的主成分分析(PCA)与有监督的线性判别分析方法(LDA)分别构建了茶叶品种鉴别模型。结果表明：对比单一预处理方法,优化组合预处理具有更优的鉴别准确性。标准正态变量变换预处理消除了茶叶样品大小不均造成的光谱散射影响,一阶导数预处理实现了变动背景的消除,减少了基线漂移的影响,突出了图谱中的有效信息,采用二者相结合的预处理方式并结合无监督的主成分分析法可实现较为准确的绿茶样品种类鉴别分析,准确率达75.0%。此外,采用有监督的线性判别分析方法处理原始光谱数据,可达到100%的鉴别准确率,但该方法需提供类别的先验知识。因此,采用近红外光谱技术和化学计量学相结合的手段可实现不同品种绿茶的快速无损鉴别。     

Feasibility study on the use of infrared spectroscopy for the direct authentication of Iberian pig fattening diet

The feasibility of using both middle- and near-infrared spectroscopy for discrimination between subcutaneous fat of Iberian pigs reared on different fattening diets has been evaluated. The sample set was formed by subcutaneous fat of pigs fattened outdoors (extensively) with natural resources (montanera) and pigs fattened on commercial feeds, either with standard feed or with especial formulations with higher content in oleic acid (HO-formulated feed). Linear discriminant analysis was used to classify the samples according to the fattening diet using the scores obtained from principal component analysis of near- and middle-infrared spectra as variables to construct the discriminant functions. The most influential variables were identified using a stepwise procedure. The discriminant potential of each spectral region was investigated. Best results were obtained with the combination of both regions with 91.7% of the standard feed and 100% of montanera and HO-formulated feed samples correctly classified. Chemical explanations are provided based on the correlation of these variables with fatty acid content in the samples.     

STUDIES ON HUMAN LENSES: II. DISTRIBUTION AND SOLUBILITY OF FLUORESCENT PIGMENTS IN CATARACTOUS AND NON-CATARACTOUS LENSES OF INDIAN ORIGIN

Abstract— Fluorometric studies of cataractous and non-cataractous human lenses were carried out to study the emission characteristics and the distribution and solubility of lenticular pigments. Most of the detected fluorophores were well distributed over the cortical and nuclear portion of the lens. The decrease in solubility of proteins with aging and cataract formation is concomitant with increasing photolysis of tryptophan. However, this is likely a phenomenon independent of the photochemical transformations of the lens proteins. The number of emitting species in the diseased lenses are higher than in the normal mature lenses. A species emitting around 375 or 388 nm is of particular interest (λ_cx, 330 nm) in that the emission characteristics of this fluorophore resemble kynurenic acid which has a high photosensitizing efficiency. The concentration of fluorescent pigments in the lenses of Indian origin is significantly high. The intense pigmentation could be attributed largely to the formation of photoproducts in the absence of normal endogenous antioxidant accumulation that is dependent on nutrition standard. If, indeed, any of these fluorescent pigments, because of their photosensitizing ability, are responsible for lenticular opacity, it is not the abundance of sunlight alone but also malnutrition that could account for the high incidence of cataract in India.     

Wheat lipids to discriminate species, varieties, geographical origins and crop years

The knowledge of lipid components of wheat finds a precious information in order to differentiate between Triticum durum (TD) and Triticum aestivum (TA). The determination of the percentages of methyl esters of the differently unsaturated fatty acids with 18-carbon atoms (C₁₈), of sterol fraction and of the other components is of particular weight. In this paper, the classification methods of linear discriminant analysis (LDA) and quadratic discriminant analysis (QDA) were applied in order to measure the classification and prediction abilities of the determined (percentages of the) components of the lipid fraction of wheat in differentiating among species, origins, varieties and crops. By univariate feature selection method (Fisher weights (FW)) and linear discriminant analysis, it was found that the only oleate is able to distinguish between the two species with a prediction rate of 100%. Inside the species Triticum durum, it was obtained a prediction rate of 83.9% while discriminating between the different origins, a prediction rate of 82.2% while discriminating among varieties and a prediction rate of 94.3% among crop years.     

Focal length variability and protein leakage as tools for measuring photooxidative damage to the lens

Hypericin is the ingredient used to standardize the popular over-the-counter antidepressant medication St. John's Wort. Because hypericin readily produces singlet oxygen and other excited state intermediates, it is a very efficient phototoxic agent in the eye that can potentially induce the development of the cataract photooxidative mechanism. Hypericin absorbs in the UV and visible ranges, binds to the lens crystallins (alpha, beta and gamma) and damages these proteins through a photooxidative mechanism. Effects were measured previously using fluorescence, UV and mass spectrometry. We report here two additional methods to monitor lens damage: (1) measuring focal length variability using a ScanTox instrument and (2) measuring protein leakage from the damaged lens. Because nonenzymic glycation results in free radical production, we chose to use elevated glucose concentrations as a convenient model for studying oxidative stress. To compare and contrast photooxidative damage against oxidative damage to the lens, we also measured the focal length variability and protein leakage induced by the presence of elevated glucose concentrations. We found that the total accumulated protein leakage was positively correlated (r = 0.9) with variability in focal length. Lenses treated with hypericin and irradiated with UVB had an increase in focal length variability as compared with the lenses that were only UVB-irradiated. Lenses without UVB irradiation had much lower focal length variability than irradiated lenses. For non-hypericin-treated lenses, UVB-irradiated lenses had a larger variability (4.58 mm) than the unirradiated lenses (1.78 mm). The lenses incubated in elevated glucose concentrations had a focal length variability (3.23 mm) equivalent to that of the unirradiated hypericin-treated lenses (3.54 mm). We conclude that photooxidative damage by hypericin results in changes in the optical properties of the lens, protein leakage and finally cataract formation. In contrast to this, high concentrations of glucose induced protein leakage but not changes in optical properties or the opacity associated with a cataract. This work provides further evidence that people should protect their eyes from intense sunlight when taking St. John's Wort.     

New discrimination method combining hit quality index based spectral matching and voting

A new discrimination method, called hit quality index (HQI)-voting, that uses the HQI for discriminant analysis has been developed. HQI indicates the degree of spectral matching between two spectra as known. In this method, a library sample yielding the highest HQI value for an unknown sample was initially searched and a group containing this sample was chosen as the group for the unknown sample. When overall spectral features of two groups are quite close to each other, many library samples with similar HQI values could be available for an unknown sample. In this situation, the simultaneous consideration of multiple votes (several library samples with close HQI values) for final decision would be more robust. In order to evaluate the discrimination performance of HQI-voting, three different near-infrared (NIR) spectroscopic datasets composed of two sample groups were used: (1) domestic and imported sesame samples, (2) domestic and imported Angelica gigas samples, and (3) diesel and light gas oil (LGO) samples. For the purpose of comparison, principal component analysis–linear discriminant analysis (PCA–LDA), partial least squares–discriminant analysis (PLS–DA) as well as k-nearest neighbor (k-NN) were also performed using the same datasets and the resulting accuracies were compared. The discrimination performances improved with the use of HQI-voting in comparison with those resulted from PCA–LDA and PLS–DA. The overall results support that HQI-voting is a comparable discrimination method to that of existing factor-based multivariate methods.     

Measurement of lens protein aggregation in vivo using dynamic light scattering in a guinea pig/UVA model for nuclear cataract

The role of UVA radiation in the formation of human nuclear cataract is not well understood. We have previously shown that exposing guinea pigs for 5 months to a chronic low level of UVA light produces increased lens nuclear light scattering and elevated levels of protein disulfide. Here we have used the technique of dynamic light scattering (DLS) to investigate lens protein aggregation in vivo in the guinea pig/UVA model. DLS size distribution analysis conducted at the same location in the lens nucleus of control and UVA-irradiated animals showed a 28% reduction in intensity of small diameter proteins in experimental lenses compared with controls (P < 0.05). In addition, large diameter proteins in UVA-exposed lens nuclei increased five-fold in intensity compared to controls (P < 0.05). The UVA-induced increase in apparent size of lens nuclear small diameter proteins was three-fold (P < 0.01), and the size of large diameter aggregates was more than four-fold in experimental lenses compared with controls. The diameter of crystallin aggregates in the UVA-irradiated lens nucleus was estimated to be 350 nm, a size able to scatter light. No significant changes in protein size were detected in the anterior cortex of UVA-irradiated lenses. It is presumed that the presence of a UVA chromophore in the guinea pig lens (NADPH bound to zeta crystallin), as well as traces of oxygen, contributed to UVA-induced crystallin aggregation. The results indicate a potentially harmful role for UVA light in the lens nucleus. A similar process of UVA-irradiated protein aggregation may take place in the older human lens nucleus, accelerating the formation of human nuclear cataract.     

“Cell adhesion resistant,UV curable,polymer zinc oxide nanocomposite materials for intraocular lens application”

Foldable acrylic lenses are used for surgical replacement of diseased intraocular lens in treatment of cataract. One of the main postsurgical complications of this treatment method is postcapsular opacification caused by proliferating epithelial cells. The most common approach taken by research community to address this issue has been modification of lens surface with hydrophobic or hydrophilic moieties to manipulate surface cell interaction. In the present study, inherently cell repellent photopolymer resins are presented. Taking advantage of zinc oxide antiproliferative properties, its nanocomposite resins were made and investigated. Hydrophobically modified zinc oxide nanoparticles and poly(phenylethylacrylate‐co‐phenylethyl methacrylate) were made, and their nanocomposite films were prepared by UV polymerization. Films made with 5 wt% ZnO nanoparticles in them resisted fibroblast attachment substantially. In addition, these films filtered harmful UV light and showed other necessary properties like visible light transparency, glass transition temperatures, mechanical strength, and biocompatibility necessary for making intraocular lenses.     

Bioaerosols chemometric characterization by laser-induced fluorescence: Air sample analysis

A laser-induced fluorescence (LIF) system was optimized using a solution of Micrococcus luteus in ethanol/water 50% (v/v) to obtain spectra in the gas phase of 46 bioaerosols. Experimental designs such as Plackett-Burman and factorial design were applied. The fluorescence spectra were treated chemometrically by principal component analysis, linear discriminant analysis and hierarchical cluster analysis to classify the microorganisms according to family, morphology and gram. The best results were obtained using LDA. The method was applied to air samples and the LIF results allowed to characterize bioaerosols reliability. The robustness of the technique was demonstrated by the identification of many bacteria.