Ameliorative Effect of Citrus Lemon Peel Extract and Resveratrol on Premature Ovarian Failure Rat Model: Role of iNOS/Caspase-3 Pathway

Premature ovarian failure (POF) is described as a loss of oocytes and the absence of folliculogenesis and is considered an adverse effect of chemotherapeutic drugs, which leads to infertility. Subsequently, the existing inquiry was achieved by exploring the potential suspicious influences of lemon peel extract (LPE), and resveratrol (RES) on cyclophosphamide (CPA) induced-POF. The results showed that CPA-induced POF significantly decreased serum estradiol (E2) and progesterone levels, along with a considerable rise in serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels. Moreover, CPA administration to rats significantly increased the serum level of Malondialdehyde (MDA) and significantly lowered the levels of reduced glutathione (GSH) and superoxide dismutase (SOD); in addition, it increased nuclear factor kappa B (NF-κB) levels, tumor necrosis factor-α (TNF-α), as well as cyclooxygenase 2 (COX-2) with the spread expression of inducible nitric oxide synthase (iNOS) mRNA levels and caspase-3 (Casp3) levels in ovarian tissues versus the control rats. However, treatment with LPE and RES suppressed the triggering of NF- κB pathways, evidenced by a considerable reduction in Casp3 & iNOS mRNA expression level and significant ameliorative effects in all evaluated parameters, as confirmed by the histological and immunohistochemical investigation when comparing the model group. In overall findings, both lemon peel extract and resveratrol can mitigate the adverse effects of CPA-induced POF. Most crucially, its combination therapy is a promising pharmacological agent for this disease.     

Solving viscoelastic free surface flows of a second‐order fluid using a marker‐and‐cell approach

This work is concerned with the numerical simulation of two‐dimensional viscoelastic free surface flows of a second‐order fluid. The governing equations are solved by a finite difference technique based on the marker‐and‐cell philosophy. A staggered grid is employed and marker particles are used to represent the fluid free surface. Full details for the approximation of the free surface stress conditions are given. The resultant code is validated and convergence is demonstrated. Numerical simulations of the extrudate swell and flow through a planar 4:1 contraction for various values of the Deborah number are presented. Copyright © 2006 John Wiley & Sons, Ltd.     

Sensitive voltammetric detection of DNA damage at carbon electrodes using DNA repair enzymes and an electroactive osmium marker

This paper presents a new approach to electrochemical sensing of DNA damage, using osmium DNA markers and voltammetric detection at the pyrolytic graphite electrode. The technique is based on enzymatic digestion of DNA with a DNA repair enzyme exonuclease III (exoIII), followed by single-strand (ss) selective DNA modification by a complex of osmium tetroxide with 2,2'-bipyridine. In double-stranded DNA possessing free 3'-ends, the exoIII creates ss regions that can accommodate the electroactive osmium marker. Intensity of the marker signal measured at the pyrolytic graphite electrode responded well to the extent of DNA damage. The technique was successfully applied for the detection of (1) single-strand breaks (ssb) introduced in plasmid DNA by deoxyribonuclease I, and (2) apurinic sites generated in chromosomal calf thymus DNA upon treatment with the alkylating agent dimethyl sulfate. The apurinic sites were converted into the ssb by DNA repair endonuclease activity of the exoIII enzyme. We show that the presented technique is capable of detection of one lesion per approximately 10(5) nucleotides in supercoiled plasmid DNA.     

Spectrophotofluorimetric Study of the Interaction between Trazodone Hydrochloride and Bovine Serum Albumin

Abstract

The binding of trazodone hydrochloride (TZH), an antidepressant drug, to bovine serum albumin (BSA) has been investigated by fluorescence spectroscopic analysis. The fluorescence emission of BSA (λ_em=350 nm) was quenched by TZH while that of this ligand was enhanced (λ_em=443 nm). The spectral behavior was consistent with the static quenching mechanism, and the apparent binding constant, K _a (1.05×10⁴ l mol^?1) as well as binding site number, n (～1), were estimated. Thermodynamic parameters obtained from the measured data at different temperatures showed that the binding of TZH to BSA involved predominantly hydrophobic interactions as well as smaller contributions from electrostatic forces. Phenylbutazone and ibuprofen were utilized as competitive markers for sites I and II, respectively, in the interaction of TZH with BSA. This competitive displacement procedure indicated that the likely binding was site I, i.e., subdomain IIA, and this was supported by the observation that up to 50% of this site marker, phenylbutazone, could be exchanged with TZH whilst only a few percent of ibuprofen were so affected.     

Finite element analysis of filling stage in die‐casting process using marker surface method and adaptive grid refinement technique

The marker surface method and the adaptive grid refinement technique have been applied to the three‐dimensional (3‐D) finite element analysis of the filling stage in the die‐casting process. Especially, the marker surface plugging technique and the marker surface regeneration technique incorporated in the marker surface method have been proposed for the efficient analysis of 3‐D practical problems. Through the marker surface plugging technique, new parts of marker surface are effective lycreated in order to eliminate the gaps between the parts of marker surface or between the edge of marker surface and cavity wall. By using the marker surface regeneration technique, the marker surface including a great number of marker elements is recreated on the basis of its original shape in order to decrease the number of marker elements and computational time. A3‐D example used as the benchmark test and a typical industrial problem of the die‐casting process have been analysed. The numerical results have been in good agreement with the experimental results and the efficiency of the adaptive grid refinement technique has been verified. It has been shown that the proposed techniques incorporated in the marker surface method and the adaptive grid refinement technique can be effectively applied to general industrial problems. Copyright © 2004 John Wiley & Sons, Ltd.     

Direct fluorometric analysis of a newly synthesised fluorescein-labelled marker for glomerular filtration rate

There is an obvious and growing medical need for an accurate determination of kidney function in the diagnosis and management of renal diseases. The glomerular filtration rate (GFR) is the accepted gold standard measurement of kidney function. Several approaches to estimate the GFR are available, but most of them are inconvenient and, therefore, of limited acceptance. A new method of quantification with fluorescein-isothiocyanate (FITC) sinistrin (FS), a novel GFR marker, has been evaluated. The method is based on the fluorescence label of FS and can be performed with a standard fluorometer. To control the interference of protein with the fluorescence signal, a calibration function was developed. The accuracy of the fluorometric method established is comparable to the so-called gold standard of enzymatic determination of polyfructosan. Moreover, FS is easy to handle and requires low-cost instruments. Our results demonstrate the potential of the direct fluorometric analysis of the new FITC-labelled marker of being a precise, simple, rapid and cost-effective method for diagnosing disturbed kidney function and monitoring its treatment efficacy. The dramatic decrease in analytical effort will result in a significantly higher acceptability of GFR determination.     

Electrochemical Enzyme Immunoassay of Tumor Marker CA15-3 with Capillary Electrophoresis

CA15-3 is a circulating antigen that is relatively specific for human breast tissue. CA15-3 is significantly more sensitive than carcinoembryonic antigen in the evaluation of patients with both primary and metastatic breast cancer. CA15-3 levels are often measured by using radioimmunoassay and enzyme immunoassay (EIA) in clinic. These methods are carried out manually. Tedious processes, slow reaction, poor reproducibility are their major problems. Capillary electrophoretic immunoassay …     

The GC-MS detection and characterization of neopine resulting from opium use and codeine metabolism and its potential as an opiate-product-use marker

Neopine, a minor opium alkaloid and an isomer of codeine (also known as -codeine), has been detected in both the urine of opium users and pharmaceutical codeine users. The characterization of neopine was achieved by comparison of the mass spectra and GC retention times of the trimethylsilyl derivative. The presence of neopine in the urine of pharmaceutical codeine users was attributed to the metabolism of codeine through a double bond migration in ring C, from the 7–8 to the 8–14 position. The potential use of the alkaloid as a confirmation marker of opium and/or pharmaceutical codeine use and the ability to differentiate these from heroin use has been discussed.     

Unambiguous NMR Structural Determination of (+)-Catechin—Laccase Dimeric Reaction Products as Potential Markers of Grape and Wine Oxidation

(+)-Catechin—laccase oxidation dimeric standards were hemi-synthesized using laccase from Trametes versicolor in a water-ethanol solution at pH 3.6. Eight fractions corresponding to eight potential oxidation dimeric products were detected. The fractions profiles were compared with profiles obtained with two other oxidoreductases: polyphenoloxidase extracted from grapes and laccase from Botrytis cinerea. The profiles were very similar, although some minor differences suggested possible dissimilarities in the reactivity of these enzymes. Five fractions were then isolated and analyzed by 1D and 2D NMR spectroscopy. The addition of traces of cadmium nitrate in the samples solubilized in acetone-d₆ led to fully resolved NMR signals of phenolic protons, allowing the unambiguous structural determination of six reaction products, one of the fractions containing two enantiomers. These products can further be used as oxidation markers to investigate their presence and evolution in wine during winemaking and wine ageing.     

表面增强拉曼光谱技术在microRNA检测中的研究进展

microRNA是一段长约为18~24个核苷酸的内源性非编码单链RNA. 最新研究发现: 许多疾病和肿瘤的发生与microRNA的表达水平息息相关, 且microRNA有望成为新型肿瘤标志物及癌症治疗的新目标. 因此, 发展高灵敏度、高特异性及简单快速的microRNA分析检测方法对于生物医学研究和癌症的早期诊断具有重要的意义. 表面增强拉曼光谱(SERS)技术由于具有灵敏度高、检测速度快、指纹识别、水干扰小等独特优势, 在癌症的早期诊断领域具有很大的应用价值. 作者综述了SERS技术在microRNA检测方面的最新研究进展, 分析了该技术在生物检测中亟待解决的关键问题和挑战, 并对其未来的发展前景进行了展望.