Glucosamine effects

Free intracellular glucosamine could readily be removed by incubation of the poisoned cells in a glucosamine free medium and its loss is accompanied by the relief of the inhibition of glycosylation. Moreover, an earlier study by Scholtissek (1975) had conclusively shown that the glucosamine effect could not be attributed to its depleting pools of cellular uridine nucleotides. It would therefore appear that glucosamine levels alone may be the real cause of inhibition. Schwarz etal (1979) quote their unpublished evidence in support... 

J.W. Anderson, R.J. Nicolosi, and J.F. Borzelleca, Glucosamine effects in humans A review of effects on glucose metabolism, side effects, safety considerations and efficacy. Food Chem. Toxicol, 43 (2), 187-201, 2005. 

Peculiar characteristics of chitins and chitosans are hemostatic action, anti-inflammatory effect, biodegradability, biocompatibihty, besides antimicrobial activity, retention of growth factors, release of glucosamine and M-acetylglucosamine monomers and oligomers, and stimulation of cellular activities [11,12,295-297]. 

Chitosan freeze-dried fleeces support chondrocyte attachment and synthesis of extracellular matrix [344]. Chitosan was used to assist the spontaneous tissue repair of the meniscus [345]. The repair of the cartilage and the prevention of its degradation in osteoarthritis is, however, possible with the association of glucosamine sulfate salt and chondroitine sulfate, the latter being particularly effective [346]. 

The landmark National Institutes of Health (NIH) study comparing glucosamine, chondroitin, glucosamine plus chondroitin, celecoxib, and placebo for OA was published recently.26 Glucosamine, chondroitin, and their combination were no more effective than placebo in decreasing pain symptoms in 1583 patients with knee OA after 24 weeks. 

Celecoxib, however, was effective. In the subgroup of patients with moderate to severe OA pain, the combination of glucosamine and chondroitin appeared to have a moderate effect, although this subgroup analysis must be interpreted with caution. On the other hand, a European study (the GUIDE trial) that compared a prescription glucosamine product with acetaminophen and placebo in patients with knee OA reported that glucosamine performed better versus placebo than did acetaminophen.27... 

Glucosamine adverse effects are mild and include GI gas, bloating, and cramps it should not be used in patients with shellfish allergies. The most common adverse effect of chondroitin is nausea. 

Q73 Gl ucosamine should be used with care in patients with impaired glucose tolerance. Glucosamine may cause nausea, abdominal pain and indigestion as side-effects. 

Glucosamine is an amino sugar derivative occurring naturally in healthy tendons, ligaments and cartilage. Its use has been shown to be effective in the symptomatic relief of osteoarthritis, especially in combination with chondroitin, also a derivative of cartilage. 

Metallic tin, Sn(0), is even more effectively employed. For example, in the presence of Sn(0), allyl bromide and a-halocarbonyl compounds afford nucleophilic organometallic species, which add to aldehydes in good yields to give homoallylic alcohols (12) and g-hydroxycarbonyl compounds (13,14) respectively. a-Diketones could be reduced by activated Sn(0), to give tin(II) enediolates which in turn undergo aldol reaction to form a,g-dihydroxyketones (15,16). This reaction was successfully applied to a stereoselective synthesis of methyl D-glucosaminate (17). 

This enzyme [EC 3.2.1.17], also called muramidase, catalyzes the hydrolysis of the l,4-/3-linkages between N-acetyl-D-glucosamine and A-acetylmuramic acid in pep-tidoglycan heteropolymers of prokaryotic cell walls. Some chitinases [EC 3.2.1.14] also exhibit this activity. See Kinetic Isotope Effect... 

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