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941.
942.
透明质素(Hyaluronan)是一种被广泛应用于临床医学领域的粘多糖类物质。有关它的药用标准相继出台。本文引用了欧洲药典2002版以及删拟定的草案对透明质酸钠制定的药用标准。同时提出了建立我国的相应标准所需的检测项目和期望采用的测试手段,为我国开展相关研究提供可供参考的工作平台。 相似文献
943.
Zhang F Wang CH Wang W Chen LX Ma HY Zhang CF Zhang M Bligh SW Wang ZT 《Phytochemical analysis : PCA》2008,19(1):25-31
A quantitative method using HPLC-MS(2) has been developed for the determination of adonifoline, one of the retronecine-type hepatotoxic pyrrolizidine alkaloids in Senecio scandens Buch.-Ham. ex D. Don., a traditional Chinese herb. Using an orthogonal design test, a simple and rapid sample extraction method was developed. HPLC analysis was conducted using a C(18) column as stationary phase and a mixture of acetonitrile and aqueous formic acid as mobile phase. Good linearity for adonifoline was found in the concentration range 0.12-4.18 microg/mL, and the HPLC-MS/MS method was shown to be appropriate, in terms of sensitivity, precision and reproducibility. The quantities of adonifoline in extracts of 18 plant samples from different collection sources and from different parts (flowers, leaves, thick stems, slim stems and roots) of S. scandens were determined using the newly developed HPLC/MS(2) analysis. 相似文献
944.
An HPTLC densitometric method for the simultaneous determination of cinnamaldehyde and eugenol as well as trace amounts of piperine in pepper-contaminated cinnamon was developed. The applicability of the method was tested with cinnamon bark powder adulterated with pepper powder, cinnamon oil, clove powder, clove oil and a commercial preparation containing cinnamaldehyde and eugenol. The method was validated for specificity, precision, accuracy and robustness. The method was found to be precise for different concentrations of cinnamaldehyde, eugenol and piperine. The accuracy of the method was checked by conducting a recovery study at three different levels. The linearity was found to be in the ranges 52.54-735.56, 533.2-8531.2 and 50-300 ng/spot, respectively, with correlation coefficients of 0.9985 +/- 0.04, 0.9982 +/- 0.06 and 0.9937 +/- 0.11 for cinnamaldehyde, eugenol and piperine. 相似文献
945.
Hashimoto M Tsushima T Murakami T Nomiya M Takada N Tanaka K 《Bioorganic & medicinal chemistry letters》2008,18(14):4228-4231
A novel γ-methylidene-spirobutanolide spirolephtoshol (1) was isolated from ascomycetous fungus Leptosphaeria doliolum as a cytotoxic compound. The relative structure was established by the NMR analysis involving the NOE experiments. Absolute structure of the bicyclic moiety was determined by chemical derivation followed by the CD analysis. The relative and absolute stereochemistry of the side chain was established by comparison of the 1H NMR spectra and the chiral GC chromatograms of the degradation product with the synthetic samples. 相似文献
946.
C. Laforsch E. Christoph C. Glaser M. Naumann C. Wild W. Niggl 《Coral reefs (Online)》2008,27(4):811-820
The surface area of corals represents a major reference parameter for the standardization of flux rates, for coral growth
investigations, and for investigations of coral metabolism. The methods currently used to determine the surface area of corals
are rather approximate approaches lacking accuracy, or are invasive and often destructive methods that are inapplicable for
experiments involving living corals. This study introduces a novel precise and non-destructive technique to quantify surface
area in living coral colonies by applying computed tomography (CT) and subsequent 3D reconstruction. Living coral colonies
of different taxa were scanned by conventional medical CT either in air or in sea water. Resulting data volumes were processed
by 3D modeling software providing realistic 3D coral skeleton surface reconstructions, thus enabling surface area measurements.
Comparisons of CT datasets obtained from calibration bodies and coral colonies proved the accuracy of the surface area determination.
Surface area quantifications derived from two different surface rendering techniques applied for scanning living coral colonies
showed congruent results (mean deviation ranging from 1.32 to 2.03%). The validity of surface area measurement was verified
by repeated measurements of the same coral colonies by three test persons. No significant differences between all test persons
in all coral genera and in both surface rendering techniques were found (independent sample t-test: all n.s.). Data analysis of a single coral colony required approximately 15 to 30 min for a trained user using the
isosurface technique regardless of the complexity and growth form of the latter, rendering the method presented in this study
as a time-saving and accurate method to quantify surface areas in both living coral colonies and bare coral skeletons.
Communicated by Biology Editor Dr Michael Lesser 相似文献
947.
The basic concept, that specialized extracellular matrices rich in hyaluronan, chondroitin sulfate proteoglycans (aggrecan, versican, neurocan, brevican, phosphacan), link proteins and tenascins (Tn-R, Tn-C) can regulate cellular migration and axonal growth and thus, actively participate in the development and maturation of the nervous system, has in recent years gained rapidly expanding experimental support. The swift assembly and remodeling of these matrices have been associated with axonal guidance functions in the periphery and with the structural stabilization of myelinated fiber tracts and synaptic contacts in the maturating central nervous system. Particular interest has been focused on the putative role of chondroitin sulfate proteoglycans in suppressing central nervous system regeneration after lesions. The axon growth inhibitory properties of several of these chondroitin sulfate proteoglycans in vitro, and the partial recovery of structural plasticity in lesioned animals treated with chondroitin sulfate degrading enzymes in vivo have significantly contributed to the increased awareness of this long time neglected structure. 相似文献
948.
In this paper, a sensitive resonance light scattering (RLS) method for the determination of protein is reported. In the Tris–HCl (pH 7.50) buffer, protein enhanced the RLS intensity of the Y3+–2‐thenoyltrifluoroacetone (TTA)–sodium dodecyl sulphate (SLS) system. The enhanced RLS intensities were in proportion to the concentrations of proteins in the range 8.0 × 10?9–1.0 × 10?5 g/mL for BSA, 1.0 × 10–8–1.0 × 10?5 g/mL for HSA and 1.0 × 10–8–1.0 × 10?6 g/mL for EA, and their detection limits were 5.0, 5.4 and 6.7 ng/mL, respectively. Actual samples were satisfactorily determined. The interaction mechanism was also studied. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
949.
Garcia EA Veridiano AM Martins JR Nader HB Pinheiro MC Joazeiro PP Toledo OM 《Cell biology international》2008,32(8):913-919
The present work quantifies hyaluronan (HA) during the late pregnancy and post-partum in order to provide a better understanding of the role of HA in the adaptations that occur in the pubic symphysis during this period. HA was quantified in situ (histochemically) and in interpubic tissue extracts by fluorimetric assay. Samples were taken from virgin mice and from pregnant animals at various stages of pregnancy: 12th-18th days into pregnancy, the day of delivery (D19) and the 3rd and 5th day post-partum. The quantitative fluorimetric analysis indicated a gradual increase of HA in the interpubic tissue throughout late pregnancy (2.4-14.6 microg/mg dry weight). This was followed by a decrease beginning on D19 (12.4 microg/mg), reaching close to virgin levels (2.2 microg/mg) on the 5th day post-partum. The same optical density changes could be seen in the HA staining. Furthermore, the histochemical analysis demonstrated the presence of HA both in the extracellular matrix of the tissue and within its cells. Such results indicate that the extracellular presence of HA may contribute to the transformation of the symphysis into a flexible structure. In addition, HA's intracellular presence (until the 18th day of pregnancy) may contribute to cellular proliferation. Finally, during parturition and on the 5th day post-partum, HA may contribute to the maintenance of the myofibroblastic phenotype of ligament cells, aiding the ligament involution after parturition. 相似文献
950.
Biophysical studies of protein–anesthetic interactions using nuclear magnetic resonance (NMR) spectroscopy are often conducted
by the addition of micro amounts of neat inhaled anesthetic which yields much higher than clinically relevant (0.2–0.5 mM)
anesthetic concentrations. We report a 19F NMR technique to measure clinically relevant inhaled anesthetic concentrations from saturated aqueous solutions of these
anesthetics (halothane, isoflurane, sevoflurane, and desflurane). We use a setup with a 3-mm NMR tube (containing trifluoroacetic
acid as standard), coaxially inserted in a 5-mm NMR tube containing anesthetic solution under investigation. All experiments
are conducted in a 5-mm NMR probe. We also have provided standard curves for four inhaled anesthetics using NMR technique.
The standard curve for each of these anesthetics is helpful in determining the prerequisite amount of aqueous anesthetic solution
required to prepare clinically relevant concentrations for protein–anesthetic interaction studies.
Parts of the results to be presented at Society for Neuroscience meeting, 2008. 相似文献