SEARCH · PubMed Health

Results for “GLUCOSAMINE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources

PubMed2003

Immunobiological effects of glucosamine in vitro.

Glucosamine (GlcN) and N-acetyl-d-glucosamine (GlcNAc) were assayed in vitro for their effects on proliferation, cytotoxicity and cytokine secretion in primary and secondary mixed lymphocyte cultures (MLCs). In addition, we studied the effect of GlcN and GlcNAc on the proliferation of purified CD4+ T cells exposed to immobilized anti-CD3 antibody. The present data show that GlcN, but not GlcNAc, inhibits CD4+ T-cell proliferation, the generation of alloreactive cytotoxic T lymphocytes (CTLs) and the secretion of interferon-gamma (IFN-gamma) and interleukin-5 (IL-5) in primary MLC. In secondary T helper-2 (Th2)-polarized MLC, GlcN, but not GlcNAc, inhibits IL-4 and IL-5 secretion, whereas no effect was found on IFN-gamma secretion in Th1-polarized MLC. Dendritic cells treated with GlcN showed a 75-80% decreased capacity for antigen cross-presentation and allostimulation. In cellular bioassays, GlcN was shown to inhibit the stimulatory activity of IL-4 and IL-2, as well as the cytotoxic activity of tumour necrosis factor-alpha (TNF-alpha). In conclusion, GlcN suppresses unprimed T-cell responses by interfering with antigen-presenting cell functions and by a direct inhibitory effect on T-cell proliferation. In addition, GlcN inhibits the secretion of cytokines in antigen-stimulated unprimed T cells and primed Th2-polarized cells.

Adjuvants, Immunologic↗

PubMed1998

Stimulation of proteoglycan production by glucosamine sulfate in chondrocytes isolated from human osteoarthritic articular cartilage in vitro.

OBJECTIVE: This study investigated the in-vitro effects of a crystalline glucosamine sulfate (GS) preparation on DNA synthesis and on proteoglycan (PG) and type II collagen (coll II) production by human articular chondrocytes isolated from human osteoarthritic articular cartilage in a 3-dimensional culture system for 4, 8, and 12 days. MATERIALS AND METHODS: Human articular chondrocytes from osteoarthritic femoral heads were isolated from their matrix by collagenase digestion and then cultured in suspension. Under constant agitation, cells aggregated and formed a cluster within a few days. The effects of GS (1-100 micrograms/ml) on chondrocytes were determined by quantifying DNA synthesis (by measurement of [3H]-thymidine uptake) as well as PG and coll II production using radiommunoassays (RIAs) specific for coll II and to human human cartilage PG. Cross-reaction with GS in the RIAs was not detected. Moreover, PG size distribution was determined by exclusion chromatography under associative conditions to determine the association of PG monomers with hyaluronic acid (HA) to form large molecular weight PG aggregates. RESULTS: Under the above conditions, PG production in culture media and chondrocyte clusters was increased by GS (10-100 micrograms/ml). DNA synthesis and coll II production were not modified by GS. In addition, GS did not modify the physico-chemical form of PG produced by cells during culture. CONCLUSIONS: Glucosamine sulfate did not affect DNA synthesis nor coll II production but caused a statistically significant stimulation of PG production by chondrocytes from human osteoarthritic cartilage cultured for up to 12 days in 3-dimensional cultures.

Aged↗

PubMed2001

Absorption, distribution, metabolism and excretion of glucosamine sulfate. A review.

This article reviews the literature related to the absorption, distribution, metabolism and excretion (ADME) of glucosamine (Gl) in man and in animals after administration of crystalline glucosamine sulfate (CGS). Intravenous administration of CGS In man, after single bolus intravenous (i.v.) injection of 1005 mg CGS (628 mg Gl), the parent Gl disappears from plasma with an apparent half life of 1.11 h. Investigations with uniformly 14C labeled Gl (14C-Gl) administered with 502 mg CGS indicate that the disappearance of Gl is due to an incorporation into the plasma globulins that occurs with a lag time of 0.45 h and a rate of 0.26 h-1. The radioactivity reaches a peak after 10 h and is eliminated with a t1/2 of 95 h. After single i.v. doses of 502 mg CGS traced with 14C-Gl, the urinary excretion in 120 h accounted for 29% of the administered dose. Consistent results are obtained in rat and dogs, in which radioactivity rapidly appears in liver, kidneys and other tissues, including the articular cartilage. In man, after i.v. bolus injection of 1005 mg CGS, the urinary excretion in 24 h of Gl determined with ion exchange chromatography was 38% of the administered dose, mostly in the first 8 h after administration. Similar results were obtained tracing CGS with 14C-Gl. Consistent results of urinary excretion were obtained in rats and dogs tracing CGS with 14C-Gl. The excretion of radioactivity in feces was small. The elimination of radioactivity with the expired air as 14CO2 measured in rats amounted to 49% of the administered dose in the 144 h following the administration, 16% of which occurred in the first 6 h. Intramuscular administration of CGS In man, a single intramuscular injection of 502 mg CGS traced with 14C-Gl, gave results similar to those after i.v. administration. Oral administration of CGS In man, after a single dose of 7.5 g CGS, Gl in plasma was below the limit of quantitation (3 micrograms/ml) of the ion exchange chromatography method. After a single dose of 314 mg CGS traced with 14C-Gl, radioactivity appeared incorporated in plasma globulins with a lag time of 1.5 h and increasing with a rate of 0.24 h-1. The peak was reached at the 9th h after administration. The radioactivity then was eliminated with a t1/2 of 58 h. The absolute oral bioavailability evaluated on the AUCs of the globulin-incorporated radioactivity was 44%. The fecal excretion in 120 h was 11.3% of the administered dose showing that at least 88.7% of the administered dose was absorbed through the gastrointestinal tract. The difference of 45% is probably due to a hepatic first-pass effect. Investigated in the rat with doses from 126 to 3768 mg CGS traced with 14C-Gl, a linear relationship was found with the AUCs as well as between doses and the Cmax of radioactivity in total and in deproteinized plasma. The urinary elimination in man of the parent Gl in 24 h determined with ion exchange chromatography after a single dose of 7.5 g of CGS was 1.19% of the administered dose, occurring mostly in the first 8 h after administration. After administration of 1884 mg repeated for 7 days the daily urinary excretion of Gl increased from 1.60% of the daily dose during the first 24 h to 2.22% of the daily dose in the last 24 h. The steady state was reached after the second day. The urinary excretion at steady state during repeated administration allowed to conclude that daily 1884 CGS administered either t.i.d. in sugar coated tablets or once a day in oral solution were bioequivalent. The elimination of radioactivity with the expired as 14CO2 measured in rats was 82% of the administered dose in the 144 h following the administration, 61% of which occur in the first 6 h. Interaction of Gl with the ADME of glucose The ADME of glucose was investigated in the rat administering i.v. or orally 14C uniformly labeled glucose. The kinetic in plasma and the tissue distribution of glucose differed totally from those of Gl, pointing out that exogenous glucose provides the energy for biochemical processes, whereas exogenous Gl acts mainly as substrate for the biosynthesis of mucopolysaccharides and of biopolymers of the articulations and bones. There was no evidence of interaction by Gl orally administered with the ADME of glucose.

Animals↗

PubMed1972

Cytochalasin B: inhibition of glucose and glucosamine transport.

Cytochalasin B has been shown to potently inhibit the transport of glucose, deoxyglucose, and glucosamine by Novikoff hepatoma cells in suspension culture without affecting their intracellular phosphorylation and metabolism. Deoxyglucose transport is inhibited by cytochalasin B in a simple competitive manner. Although this inhibition is not sufficient to explain the biological action of the drug on cytokinesis, it does explain earlier observations on inhibition by cytochalasin B of the incorporation of glucose and glucosamine, and probably of other extracellular precursors, into macromolecules by various types of cells.

Animals↗

PubMed1976

Carbohydrate moieties of procollagen: incorporation of isotopically labeled mannose and glucosamine into propeptides of procollagen secreted by matrix-free chick embryo tendon cells.

Cells obtained from chick embryo tendons incorporate isotopically labeled glucosamine and mannose into the pro-alpha1 and pro-alpha2 chains of procollagen as judged by sodium dodecyl sulfate-gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The label was further localized to the propeptides of pro-alpha1 and pro-alpha2 by its chromatographic behavior after digestion with bacterial collagenase or alpha-chymotrypsin. Carbohydrate analysis of isolated pro-alpha chains showed the presence of labeled galactosamine in addition to mannose and glucosamine. Resistance to mild alkaline hydrolysis suggested that greater than 90% of the oligosaccharide units are not linked to the propeptide backbone by either serine or threonine.

Animals↗

PubMed1984

Tunicamycin blocks neuritogenesis and glucosamine labeling of gangliosides in developing cerebral neuron cultures.

Fetal cerebral neurons at the initiation of active neurite outgrowth in culture incorporate 4-fold more [3H]glucosamine into glycoproteins than into the cellular lipid fraction. After 8 days or longer, when a well-developed fiber network is apparent, lipids are labeled more extensively than the glycoproteins. Labeling of the latter is inhibited 95% and 89% by 0.5 microgram of tunicamycin per ml added to 1-day-old and 8-day-old cultures, respectively. Labeling of glycolipids is inhibited 30% in 1-day-old and 86% in 8-day-old cultures. Tunicamycin blocks incorporation of glucosamine label into practically all ganglioside species except for a resorcinol-positive, sialidase-sensitive band tentatively identified as GQ1b tetrasialoganglioside (Svennerholm ganglioside nomenclature). It also substantially reduces binding of 125I-labeled tetanus toxin to intact cells. There is 14% and 27% reduction in the total ganglioside sialic acid content in 1-day-old and 8-day-old cells treated for 24 hr with 0.5 microgram of tunicamycin per ml, but no substantial compositional changes are encountered. Tunicamycin blocks neurite outgrowth when added to cells soon after plating but causes no retraction or losses of fibers once the fiber network is established. Therefore, inhibition of neurite outgrowth by tunicamycin is not due to an effect on cellular gangliosides but can be correlated to an inhibition of protein glycosylation.

Animals↗

PubMed2002

Kinetic characterization of human glutamine-fructose-6-phosphate amidotransferase I: potent feedback inhibition by glucosamine 6-phosphate.

Glutamine-fructose-6-phosphate amidotransferase (GFAT) catalyzes the first committed step in the pathway for biosynthesis of hexosamines in mammals. A member of the N-terminal nucleophile class of amidotransferases, GFAT transfers the amino group from the L-glutamine amide to D-fructose 6-phosphate, producing glutamic acid and glucosamine 6-phosphate. The kinetic constants reported previously for mammalian GFAT implicate a relatively low affinity for the acceptor substrate, fructose 6-phosphate (Fru-6-P, K(m) 0.2-1 mm). Utilizing a new sensitive assay that measures the production of glucosamine 6-phosphate (GlcN-6-P), purified recombinant human GFAT1 (hGFAT1) exhibited a K(m) for Fru-6-P of 7 microm, and was highly sensitive to product inhibition by GlcN-6-P. In a second assay method that measures the stimulation of glutaminase activity, a K(d) of 2 microm was measured for Fru-6-P binding to hGFAT1. Further, we report that the product, GlcN-6-P, is a potent competitive inhibitor for the Fru-6-P site, with a K(i) measured of 6 microm. Unlike other members of the amidotransferase family, where glutamate production is loosely coupled to amide transfer, we have demonstrated that hGFAT1 production of glutamate and GlcN-6-P are strictly coupled in the absence of inhibitors. Similar to other amidotransferases, competitive inhibitors that bind at the synthase site may inhibit the synthase activity without inhibiting the glutaminase activity at the hydrolase domain. GlcN-6-P, for example, inhibited the transfer reaction while fully activating the glutaminase activity at the hydrolase domain. Inhibition of hGFAT1 by the end product of the pathway, UDP-GlcNAc, was competitive with a K(i) of 4 microm. These data suggest that hGFAT1 is fully active at physiological levels of Fru-6-P and may be regulated by its product GlcN-6-P in addition to the pathway end product, UDP-GlcNAc.

Animals↗

PubMed2001

A randomized double-blind clinical trial of the effect of chondroitin sulfate and glucosamine hydrochloride on temporomandibular joint disorders: a pilot study.

Previous studies have shown chondroitin sulfate and glucosamine hydrochloride have beneficial effects on symptoms of osteoarthritis of the knee. Our aim was to study the effect of a daily dose of 1500 mg of glucosamine hydrochloride (GH) and 1200 mg of chondroitin sulfate (CS) taken for twelve weeks on subjects diagnosed with capsulitis, disk displacement, disk dislocation, or painful osteoarthritis of the temporomandibular joint (TMJ). Forty-five subjects were enrolled in the study and were randomly assigned to either an active medication group or a placebo group. Eleven subjects were lost from the study for various reasons, resulting in fourteen subjects remaining in the active medication group and twenty subjects remaining in the placebo group. Subjects taking CS-GH had improvements in their pain as measured by one index of the McGill Pain Questionnaire, in TMJ tenderness, in TMJ sounds, and in the number of daily over-the-counter medications needed. Subjects taking the placebo medication had improvements in their pains as measured by the visual analog scale and by four indices of the McGill Pain Questionnaire. Additional studies are required to evaluate the clinical effectiveness of CS-GH and to determine the exact mechanism by which CS-GH affects the articular cartilage of synovial joints.

Adult↗

PubMed2001

The effect of an oral supplement containing glucosamine, amino acids, minerals, and antioxidants on cutaneous aging: a preliminary study.

BACKGROUND: Alterations in collagen, elastin, and glycosaminoglycans contribute to cutaneous changes seen in aging skin. METHODS: A randomized, controlled, single-blind study was conducted with 53 female volunteers who were supplied with an oral supplement containing glucosamine, amino acids, minerals, and various antioxidant compounds. Hydration properties of the skin as well as textural analysis of the women's fine lines and wrinkles were assessed following 5 weeks intake of the oral supplement and results were compared with those of a control group of 12 individuals who did not take the supplement. RESULTS: There was a statistically significant reduction (34%) in the number of visible wrinkles as measured by the silflo replicas (P < 0.01) and a reduction (34%) in the number of fine lines (P < 0.06) in the group of women who took the supplement. No significant changes in epidermal hydration were observed in either the control or study groups. CONCLUSION: The use of an oral supplement containing glucosamine, minerals, and various antioxidant compounds can potentially improve the appearance of visible wrinkles and fine lines. It does not, however, affect epidermal hydration.

Administration, Oral↗

PubMed2006

Hyperglycemia and glucosamine-induced mesangial cell cycle arrest and hypertrophy: Common or independent mechanisms?

The Hexosamine Pathway (HP) is one hypothesis proposed to explain glucose toxicity and the alterations observed during the course of diabetic microvascular complication development. Glucosamine is a precursor of UDP-N-Acetylglucosamine (UDP-GlcNAc), the main product of the HP that has often been used to mimic its activation. The transfer of a UDP-GlcNAc residue onto proteins (O-GlcNAc modification) represents the final step of the HP and is considered as a major mechanism by which this pathway exerts its signalling effects. While it is well accepted that the HP promotes extracellular matrix accumulation in the context of diabetic nephropathy, its involvement in the perturbations of cell cycle progression and hypertrophy of renal cells has been poorly investigated. Nevertheless, in a growing number of studies, the HP and O-GlcNAc modification are emerging as important regulators of cell cycle progression. This review will focus on the role of glucosamine and O-GlcNAc modification in cell cycle regulation in the context of diabetic nephropathy. Special emphasis will be given into the role of the HP as a potential mediator of the effects of high glucose on the perturbations of renal cell growth.

Animals↗

PubMed1993

Neonatal porcine endometrial development involves coordinated changes in DNA synthesis, glycosaminoglycan distribution, and 3H-glucosamine labeling.

To determine whether neonatal porcine endometrial development involved alterations in endometrial DNA synthesis, glycosaminoglycan (GAG) distribution, and/or 3H-glucosamine labeling, gilts were assigned randomly at birth (Day 0) to be hysterectomized on either Day 0, 7, 14, 28, 42, or 56. Uteri were processed for histology and Alcian blue-8GX (AB) histochemistry or cultured as explants in the presence of [methyl-3H]thymidine (3H-Thd) or D-[6-3H]glucosamine (3H-GlcN) and processed for subsequent autoradiography. For 3H-Thd-labeled tissues, labeling index (LI; % of nuclei labeled) was determined for two endometrial tissues (epithelium and stroma); two epithelial areas (luminal and glandular); and, for glandular epithelium, in three endometrial zones (zone 1 = shallow, zone 2 = intermediate, zone 3 = deep). For 3H-GlcN-labeled tissues, LI (grains/100 microns2) was determined for two stromal zones (shallow and deep). Endometrial glands were absent on Day 0, present in shallow stroma on Days 7 and 14, and extended to the myometrium in tissues from Day 28 through Day 56. Appearance of endometrial glands was associated with a dramatic increase in glandular epithelial 3H-Thd LI, which was maximal on Days 7 and 14 and declined thereafter. When glands were present in all three endometrial zones (Days 28-56), glandular epithelial 3H-Thd LI was consistently greatest in zone 2. Stromal 3H-Thd LI decreased after Day 0. In tissues obtained after Day 0, a distinct zone of alcianophilia was observed in shallow stroma adjacent to luminal epithelium and surrounding the necks of newly developed endometrial glands. This staining pattern was marked in tissues from Days 7, 14, and 28. Generally, stromal 3H-GlcN LI was greater in shallow than in deep stromal zones; it decreased after Day 0 to minimum values on Days 28 and 42 in both zones, and increased slightly in shallow stroma on Day 56. Data indicate that development of the neonatal porcine endometrium between birth and Day 56 involves coordinated alterations in patterns of DNA synthesis, GAG distribution, and glycoconjugate biosynthesis. The morphogenetic processes characterized here are likely to be regulated locally via changes in tissue microenvironment.

Animals↗

PubMed2003

Naturocetic (glucosamine and chondroitin sulfate) compounds as structure-modifying drugs in the treatment of osteoarthritis.

PURPOSE OF REVIEW: Several entities have been investigated carefully for the symptomatic and structural management of osteoarthritis. This review reports recent findings suggesting that such compounds may delay the structural progression of osteoarthritis. RECENT FINDINGS: The most compelling evidence of a potential for inhibiting the structural progression of osteoarthritis has been obtained with glucosamine sulfate, whereas preliminary results obtained in patients with osteoarthritis of the hands also suggest that chondroitin sulfate could be used in the same indication. At any rate, these two compounds have clearly demonstrated a symptomatic action, mainly in osteoarthritis of the lower limbs. Patients with the less severe radiographic osteoarthritis will experience, in the long run, the most dramatic disease progression in terms of joint space narrowing. Such patients may be particularly responsive to structure-modifying drugs. SUMMARY: Glucosamine sulfate has demonstrated its ability to reduce the progression of osteoarthritis in the lower limbs. The preliminary results obtained in the hands suggest that chondroitin sulfate could also be of interest in this indication. An important issue is that all the conclusive studies with such chemical entities resulted from the use of prescription medicines, not over-the-counter pills or food supplements.

Antirheumatic Agents↗

PubMed2006

Glucosamine administration during resuscitation improves organ function after trauma hemorrhage.

Stress-induced hyperglycemia is necessary for maximal rates of survival after severe hemorrhage; however, the responsible mechanisms are not clear. One consequence of hyperglycemia is an increase in hexosamine biosynthesis, which leads to increases in levels of O-linked attachment of N-acetyl-glucosamine (O-GlcNAc) on nuclear and cytoplasmic proteins. This modification has been shown to lead to improved survival of isolated cells after stress. In view of this, we hypothesized that glucosamine (GlcNH2), which more selectively increases the levels of O-GlcNAc administration after shock, will have salutary effects on organ function after trauma hemorrhage (TH). Fasted male rats that underwent midline laparotomy were bled to a mean arterial blood pressure of 40 mmHg for 90 min and then resuscitated with Ringer lactate (four times the shed blood volume). Administration of 2.5 mL of 150 mmol L GlcNH2 midway during resuscitation improved cardiac output 2-fold compared with controls that received 2.5 mL of 150 mmol L NaCl. GlcNH2 also improved perfusion of various organs systems, including kidney and brain, and attenuated the TH-induced increase in serum levels of IL-6 (902+/-224 vs. 585+/-103 pg mL) and TNF-alpha (540+/-81 vs. 345+/-110 pg mL) (values are mean+/-SD). GlcNH2 administration resulted in significant increase in protein-associated O-GlcNAc in the heart and brain after TH. Thus, GlcNH2 administered during resuscitation improves recovery from TH, as assessed by cardiac function, organ perfusion, and levels of circulating inflammatory cytokines. This protection correlates with enhanced levels of nucleocytoplasmic protein O-GlcNAcylation and suggests that increased O-GlcNAc could be the mechanism that links stress-induced hyperglycemia to improved outcomes.

Animals↗

PubMed1984

Protein synthesis and amino acid pool during yeast-mycelial transition induced by N-acetyl-D-glucosamine in Candida albicans.

Protein synthesis at different stages of yeast-mycelial transition induced by N-acetyl-D-glucosamine in Candida albicans was evaluated by following incorporation of radioactive amino acids into the acid-insoluble cellular material. In passing from the early germ-tube formation (60-90 min) to the mature hyphal cell (240-270 min) there was a marked decrease in the capacity for protein synthesis. Apparently, this decrease was not due to a decreased amino acid uptake into the soluble cellular pool or to exhaustion of carbon/energy source in the inducing medium with consequent arrest of growth. Protein synthesis, however, did not decay when amino acids at high concentration were added to the medium fostering the yeast-mycelial transition and this effect was potentiated by glucose. Analysis of the intracellular amino acid pool showed that both germ-tubes and hyphal cells were relatively depleted of several amino acids as compared to the yeast-form cells, whereas in the hyphae there was a higher concentration of glutamic acid/glutamine, the latter being the predominant component. These modulations in amino acid pool composition were not seen when yeasts were converted to hyphae in an amino acid-rich induction medium. This study emphasizes that yeast-form cells of C. albicans may efficiently convert to the mycelial form even under a progressively lowered rate of protein synthesis, and suggests that initiation of hyphal morphogenesis in the presence of N-acetyl-D-glucosamine is somehow separated from cellular growth.

Acetylglucosamine↗

PubMed1989

Controlling the growth rate of Saccharomyces cerevisiae cells using the glucose analogue D-glucosamine.

By using competition between glucose and its analogue D-glucosamine, we have produced a system in which it is possible to vary the steady-state growth rate of populations of Saccharomyces cerevisiae cells without otherwise altering the composition of the medium or significantly affecting catabolite repression. We demonstrate that D-glucosamine inhibits the accumulation of glucose derived label and the phosphorylation of glucose by hexokinase (EC 2.7.1.1).

Cell Division↗

PubMed2000

Reduced virulence of Candida albicans mutants lacking the GNA1 gene encoding glucosamine-6-phosphate acetyltransferase.

The yeast GNA1 gene encodes glucosamine-6-phosphate acetyltransferase which catalyses the reaction of glucosamine 6-phosphate with acetyl-CoA to form N-acetylglucosamine 6-phosphate, a fundamental precursor in UDP-N-acetylglucosamine biosynthesis. Candida albicans mutants lacking GNA1 were viable in the presence of N-acetylglucosamine. To confirm the physiological importance of C. albicans GNA1, the virulence of a C. albicans gna1Delta null mutant was examined in a mouse model of candidiasis. When injected intravenously into mice, the virulence of the C. albicans gna1Delta null mutant was significantly attenuated. The reduced virulence appeared to be the result of rapid clearance from host tissue. These data suggest that C. albicans GNA1 is required for survival of the fungus in host animals, probably because an insufficient level of N-acetylglucosamine is available from the host tissues.

Acetyltransferases↗

PubMed2005

N-retinoyl-D-glucosamine, a new retinoic acid agonist, mediates topical retinoid efficacy with no irritation on photoaged skin.

BACKGROUND: Chronic ultraviolet (UV) radiation from sunlight induces wrinkle formation. Retinoic acid (RA) can markedly improve wrinkles, although RA does have some side-effects, such as skin irritation. As the efficacy and cytotoxicity of RA has been traced to its free carboxylic acid, we synthesized a new molecule, N-retinoyl-D-glucosamine (GRA), in which a glucosamine has been attached to the polar end group of all-trans retinoic acid. OBJECTIVES: To analyse the effect of topical GRA in wrinkle repair and anti-irritation in photoaged mice compared with topical RA, as well as to determine retinoic acid receptor (RAR) and retinoid X receptor (RXR) transactivation activity in vitro. METHODS: Hairless mice were irradiated with 60 mJ cm-2 of UVB for 10 weeks, and then topically treated with 0.05% GRA or 0.05% RA for 8 weeks. An in vitro transcriptional assay was performed and the activity of GRA in 293 cells transfected with RAR-alpha or RXR-alpha expression plasmid and luciferase reporter plasmid then determined. RESULTS: Topical GRA and RA brought about almost complete disappearance of the wrinkles caused by UVB irradiation. The two ligands promoted both a wide repair zone histologically, and the expression of type 1 collagen in the skin. In contrast, topical GRA treatment did not produce irritation such as erythema or roughness, or alteration of transepidermal water loss values, compared with RA. In the in vitro luciferase assay, GRA resulted in significant dose-dependent RAR transactivation activity in a 100 times higher concentration range than RA. GRA did not mediate RXR transactivation activity at all. CONCLUSIONS: Topical GRA appears to be able to repair photoaged skin damage without any of the irritation caused by topical RA, probably via RAR transactivation activity.

Administration, Topical↗

PubMed1977

The action of lysozyme on peptidoglycan with N-unsubstituted glucosamine residues. Isolation of glycan fragments and their susceptibility to lysozyme.

1. A peptidoglycan preparation N-acetylated at about 30% of glucosamine residues was obtained by the treatment of the lysozyme-resistant cell wall paptidoglycan of Bacillus cereus with acetic anhydride at pH 7. Fractionation of dialyzable material resulting from lysozyme digestion of the glycan component of this peptidoglycan preparation yielded five oligosaccharides designated as S1 to S5 besides the disaccharide GlcNAc-MurAc. 2. Oligosaccharide S3, which accounted for about 30% of the disaccharide units recovered as disaccharides and oligosaccharides, was identified as GlcN-MurAc-GlcNAc-MurAc. Oligosaccharide S1, accounting for about 20% of the disaccharide units recovered, was characterized as GlcN-MurAc-GlcN-MurAc-GlcNAc-MurAc, while oligosaccharide S2, present in a smaller amount, as GlcNAc-MurAc-GlcN-MurAc-glcNAc-MurAc. Oligosaccharides S4, and S5, present in small amounts, were identified as GlcNAc-MurAc-GlcNAc-MurAc and MurAc-GlcNAc-MurAc, respectively. 3. Oligosaccharides S1, S3 and S5 proved to be completely insusceptible to lysozyme, whereas S2 was digsted by lysozyme to produce GlcNAc-MurAc and S3. S1 was found to act as a more potent inhibitor than S3 in lysozyme-catalyzed digestion of polysaccharides. 4. The results obtained show that the lysozyme-catalyzed hydrolysis of peptidoglycan oligosaccharides had an obligatory requirement for the N-acetyl group on the glucosamine residue located in subsite C in the enzyme-substrate complex.

Bacillus cereus↗