1,721,121 research outputs found
Capillary electrophoresis of carbohydrates: From Monosaccharides to complex polysaccharides
No full textAn essential text for anyone exploring the myriad possibilities of this rapidly expanding field Offers a comprehensive look at the latest breakthroughs and improvements in CE and CE techniques applied to carbohydrates from monosaccharides up to complex oligosaccharides and polysaccharides Provides an overview of the application of CE and CE-mass spectrometry Simple carbohydrates, complex oligosaccharides and polysaccharides all belong to a class of ubiquitous (macro)molecules that exhibit a wide range of biological functions, and the recent advent of enhanced enzymatic, chemical and analytical tools used to study these sugars has inaugurated a genuine explosion in the field of glycomics. Specifically, it has led to a deeper understanding of how specific sugar structures modulate cellular phenotypes, and that breakthrough has led to the discovery of new pharmaceuticals for the treatment of many serious diseases, such as cancer. The subsequent rapid expansion of this research holds high promise for future therapeutic regimens, and capillary electrophoresis (CE) refers to the range of related separation techniques that are integral to this vital research. CE uses narrow-bore fused-silica capillaries to separate a complex array of large and small molecules, and Capillary Electrophoresis of Carbohydrates offers a comprehensive look at the latest breakthroughs and improvements in CE and CE techniques applied to monosaccharides up to complex oligosaccharides and polysaccharides. It begins with an overview of the application of CE and CE- mass spectrometric in the analysis of simple carbohydrates without any previous derivatization step before discussing various detection techniques such as spectrophotometric detection, electrochemical detection and other less common techniques. It then covers in detail an array of related topics and numerous applications. It is an essential text for anyone exploring the myriad possibilities of this rapidly expanding field
Chondroitin Sulfate Safety and Quality.
Full text linkThe industrial production of chondroitin sulfate (CS) uses animal tissue sources as raw
material derived from dierent terrestrial or marine species of animals. CS possesses a heterogeneous
structure and physical-chemical profile in dierent species and tissues, responsible for the various
and more specialized functions of these macromolecules. Moreover, mixes of dierent animal tissues
and sources are possible, producing a CS final product having varied characteristics and not well
identified profile, influencing oral absorption and activity. Finally, dierent extraction and purification
processes may introduce further modifications of the CS structural characteristics and properties
and may lead to extracts having a variable grade of purity, limited biological eects, presence of
contaminants causing problems of safety and reproducibility along with not surely identified origin.
These aspects pose a serious problem for the final consumers of the pharmaceutical or nutraceutical
products mainly related to the traceability of CS and to the declaration of the real origin of the active
ingredient and its content. In this review, specific, sensitive and validated analytical quality controls
such as electrophoresis, eHPLC (enzymatic HPLC) and HPSEC (high-performance size-exclusion
chromatography) able to assure CS quality and origin are illustrated and discussed
Heparin from marine mollusks: Occurrence, structure, and biological role
No full textSeveral invertebrate species contain variable amounts of one or more types of sulfated
glycosaminoglycans (GAGs). At present it is well known the existence of a species-specific sulfated
GAGs composition based on the relative amount and type of chondroitin sulfates, heparan sulfate
and heparin. Heparin is a sulfated polysaccharide belonging to the family of GAGs with numerous
important biological activities, such as anticoagulant and antithrombotic properties that derive from its
interaction with diverse proteins. Unusual heparin samples for molecular mass, fine structural
organization and anticoagulant activity, are isolated and characterized from molluscs. Variable
presence of the trisulfated disaccharide [DUA2S(1->4)-a-D-GlcN2S6S] and significant modifications of
the disaccharides bearing non-sulfated iduronic and glucuronic acids, [->4)-a-L-IdoA(1->4)-a-DGlcNAc6S(
1-> and ->4)-a-L-IdoA(1->4)-a-D-GlcN2S6S(1->] and [->4)-b-D-GlcA(1->4)-a-DGlcN2S6S(
1->], and oligosaccharide sequences bearing part of the ATIII-binding region,
[DUA2S(1->4)-a-D-GlcN2S6S(1->4)-b-D-GlcA(1->4)-a-D-GlcN2S3S6S] and [DUA2S (1->4) -a-DGlcN2S6S
(1->4)-a-L-IdoA (1->4)-a-D-GlcNAc6S (1->4)-b-D-GlcA (1->4)-a-D-GlcN2S3S6S], are
detected and measured in heparin samples derived from different clam species. This review more
specifically deals with structural and biologically important aspects of heparin in invertebrates with
special emphasis on the heparin from molluscs. Furthermore, the fine characterization of heparin
from Tapes phylippinarum and Callista chione is reported
High levels of C3c in the cerebrospinal fluid from amyotrophic lateral sclerosis patients
No full textA study of several parameters of the humoral immunity in the serum and the cerebrospinal fluid (CSF) of thirteen Amyotrophic Lateral Sclerosis (ALS) patients was carried out. A significant increase in CSF C3c was shown. This feature was found to be significantly correlated to the CSF albumin/serum albumin ration (r = 0.70; p less than 0.05) and to the total CSF proteins (r = 0.86; p less than 0.01). The possible effect of the blood-brain barrier breakdown on the CSF complement levels was evaluated. On the basis of the recently found biochemical changes in ALS cell membranes it is proposed that the high levels of the CSF C3c may also be due to a defective binding to the lymphocytes C3 receptors
High-throughput glycosaminoglycan extraction and UHPLC-MS/MS quantification in human biofluids
No full textGlycosaminoglycans (GAGs) are linear, unbranched heteropolysaccharides whose structural complexity determines their function. Accurate quantification of GAGs in biofluids at high throughput is relevant for numerous biomedical applications. However, because of the structural variability of GAGs in biofluids, existing protocols require complex pre-analytical procedures, have limited throughput and lack accuracy. Here, we describe the extraction and quantification of GAGs by using ultra-high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry (UHPLC-MS/MS). Designed for 96-well plates, this method enables the processing of up to 82 study samples per plate, with the remaining 14 wells used for calibrators and controls. Key steps include the enzymatic depolymerization of GAGs, their derivatization with 2-aminoacridone and their quantification via UHPLC-MS/MS. Each plate can be analyzed in a single UHPLC-MS/MS run, offering the quantitative and scalable analysis of 17 disaccharides from chondroitin sulfate, heparan sulfate and hyaluronic acid, with a level of precision and reproducibility sufficient for their use as biomarkers. The procedure from sample thawing to initiating the UHPLC-MS/MS run can be completed in similar to 1.5 d plus 15 min of MS runtime per sample, and it is structured to fit within ordinary working shifts, thus making it a valuable tool for clinical laboratories seeking high-throughput analysis of GAGs. The protocol requires expertise in UHPLC-MS/MS
Uronic acid carbazole assay and cetylpyridinium chloride titration depend on the chondroitin sulfate molecular weight
No full textChondroitin sulfate (CS) of various molecular weight (MW), up to ∼3 kDa, were produced and tested for uronic acid carbazole assay and cetylpyridinium chloride (CPC) titration showing an evident decrease in the assays depending on the CS MW. The described results for uronic acid assay by carbazole reaction and CPC titration of CS poses the problem to know the MW values before their application and to use comparable standards to obtain reliable results. Otherwise, the related quantitative data can be affected by a great error and fake certificate of analysis
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
