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Glycosaminoglycans
Published in Luke R. Bucci, Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Bioavailability of oral glucosamine, glucosamine sulfate, or N-acetylglucosamine is excellent.1305–1307 Studies utilizing radioactive glucosamine salts found that glucosamine was absorbed intact and almost completely, with only 5% excreted in feces of rats.1306 Glucosamine levels in plasma reached a broad peak at 1 h that continued for 10 h.1307 After a very short time (<60 min), radioactivity in the form of glycoproteins was also encountered in plasma. Thus, glucosamine was taken up and utilized very quickly by peripheral tissues. Most of the ingested glucosamine (82%) was metabolized into carbon dioxide and expired. However, significant levels of radioactivity were found in all organs, including femoral cartilage, femurs, and sternum, which possessed the same levels as plasma 8 h after administration. Further studies in dogs showed that articular cartilage had active uptake of glucosamine from plasma. Thus, oral administration of glucosamine leads to rapid, complete absorption and uptake by all tissues, including connective tissues, in animals.
Nutraceuticals and Functional Foods
Published in Robert E.C. Wildman, Richard S. Bruno, Handbook of Nutraceuticals and Functional Foods, 2019
Another homopolysaccharide is pectin, where the repeating subunits are largely methylgalacturonic acid units. It is a jelly-like material that acts as a cellular cement in plants. The linkage between the subunits is also β1-4 bonds. The carboxyl groups become methylated in a seemingly random manner as fruit ripen. Chemically related to pectin is chitin. Chitin is not a plant polysaccharide but is found within the animal kingdom, although not necessarily in humans. It is a β1-4 homopolymer of N-acetyl-glucosamine found in shells or exoskeletons of insects and crustacea. Chitin has been positioned as a dietary ingredient for weight loss.
Multiple Roles of Cardiac Metabolism: New Opportunities for Imaging the Physiology of the Heart
Published in Robert J. Gropler, David K. Glover, Albert J. Sinusas, Heinrich Taegtmeyer, Cardiovascular Molecular Imaging, 2007
In preliminary experiments, we observed that altered glucose homeostasis through feeding of an isocaloric low carbohydrate, high fat diet completely abolishes MHC isoform switching in the hypertrophied heart (32). One mechanism by which glucose affects gene expression is through O-linked glycosylation of transcription factors. Glutamine, fructose-6-phosphate amidotransferase (gfat) catalyzes the flux-generating step in UDP-N-acetylglucosamine biosynthesis, the rate determining metabolite in protein glycosylation (Fig. 7). In preliminary studies, we observed that overload increases the intracellular levels of UDP-N-acetylglucosamine (unpublished work in collaboration with Dr. Don McClain, University of Utah). Thus, there is early evidence for glucose-regulated gene expression in the heart and, more specifically, for the involvement of glucose metabolites in isoform switching of sarcomeric proteins. More importantly, excess O-GlcNAcylation in the diabetic heart appears to play a significant role in cardiac function because reducing this excess cellular O-GlcNAcylation improves calcium handling and cardiac contraction in diabetic mice (63).
Hyaluronic acid in vulvar and vaginal administration: evidence from a literature systematic review
Published in Climacteric, 2021
G. Buzzaccarini, L. Marin, M. Noventa, A. Vitagliano, A. Riva, F. Dessole, G. Capobianco, L. Bordin, A. Andrisani, G. Ambrosini
Hyaluronic acid (HA) is a fundamental component of the extracellular matrix, which has remained largely unchanged throughout animal evolution, with hydrating and lubricant properties. In particular, it is a glycosaminoglycan composed of repeating units of disaccharides, d-glucuronic acid and N-acetylglucosamine molecules linked by β-(1–4) and β-(1–3). In esthetic medicine, HA is widely used thanks to its water-binding property, which can provide a lubricating and moisturizing effect on tissue [1]. Actually, cross-linked HA and non-cross-linked HA are some of the most requested and appreciated esthetic medicine procedures for facial rejuvenation. In particular, it is used both for biostimulation and facial remodeling, filling facial cavities that are crumbling due to reabsorbed bone, fat or subcutaneous matrix [2–4]. HA usage is now gaining widespread popularity in different clinical fields related to esthetic medicine, such as esthetic gynecology, and is taken into consideration for many different and innovative purposes.
An overview of ProTide technology and its implications to drug discovery
Published in Expert Opinion on Drug Discovery, 2021
Michaela Serpi, Fabrizio Pertusati
Phosphor(n)amidate technology was applied to carbohydrates, a class of very hydrophilic compounds. McGuigan et al reported the conversion of N-acetylglucosamine to a series of O-6 [117], O-3 and O-4 aryloxy phosphoramidate prodrugs [118], evaluated for their potential chondroprotective activity against osteoarthritis. By comparison to the parent drug, some of the analogues showed a significant enhancement in the inhibition of inflammatory cytokine-induced proteoglycan degradation. Specifically, the O-3 and O-4 (L)-proline prodrugs proved to be the most active of the series, and well processed in chondrocytes. Data on human cartilage supported the notion that these novel O-3 and O-4 regioisomers may represent novel promising leads for osteoarthritis treatment. These findings showed that amino acids other than L-alanine, can be effective promoieties in this technology.
Ulva lactuca methanolic extract improves oxidative stress-related male infertility induced in experimental animals
Published in Archives of Physiology and Biochemistry, 2021
Doaa A. Ghareeb, Alshimaa Abd-Elgwad, Nihal El-Guindy, Galila Yacout, Hala H. Zaatout
An aliquot of 0.8 mL hyaluronate solution (1.25 g/L in acetate buffer, the acetate buffer prepared with 50 mM concentration, pH 4 containing 150 mM sodium chloride) was preincubated for 15 min at 37 °C. An aliquot of 0.2 mL buffered sample (135 µL spermatozoa mixed with 67.5 µL acetate buffer) was mixed with hyaluronate and incubated for 10 min at 37 °C (tested solution). An aliquot of 500 µL of tested solution was added to 0.1 mL tetraborate (0.8 M, pH 9.1) and heated for 3 min in boiling water bath then cooled. Three millilitres dimethylaminobenzaldehyde, 1% (4-dimethylaminobenz-aldehyde in acetic acid containing 12.5 v/v hydrochloric acid, 10 M, before used, the solution was diluted with 9 volumes acetic acid) reagent was added then the solution was incubated for 20 min at 37 °C. Blank solution was prepared by mixing 0.1 mL tetraborate solution, 0.4 mL hyaluronate, and 0.1 mL sample. An aliquot of 500 µl of standard N-acetylglucosamine solutions (10 µg/mL in acetate buffer) or blank solution was added instead of tested solution and the previous procedure was carried out. The obtained colour was estimated at 585 nm against blank (Leaback and Walker 1963).