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At least 73 records · Page 4Linked to original sources
PubMed1975

The co-polymeric structure of pig skin dermatan sulphate. Distribution of L-iduronic acid sulphate residues in co-polymeric chains.

1. Pig skin dermatan sulphate was degraded by periodate oxidation followed by alkaline elimination or by chondroitinase-ABC to quantify irregular repeating units, i.e. those containing D-GlcUA (D-glucuronic acid) and L-IdUA-SO4 (sulphated iduronic acid). 2. Previous results of periodate oxidation (Fransson, 1974) indicated repeating sequences in pig skin dermatan sulphate containing, on average, 3D-GlcUA, 9 L-IdUA-SO4 or 28 L-IdUA units in addition to N-acetylgalactosamine sulphate. However, complete digestion with chondroitinase-ABC yielded, at the most, 3-4 disulphated disaccharides/chain. Consequently, more than one-half of the L-IdUA-SO4 residues were present in monosulphated periods, i.e. IdUA-(SO4)-GalNAc. 3. To determine the location of L-IdUA-SO4 residues along the copolymeric chain dermatan sulphate was digested with testicular hyaluronidase. (This enzyme cleaves GalNAc-GlcUA bonds within block regions containing D-GlcUA.) By NaB3H4 reduction GalNAc residues located in the reducing end of the fragments were converted into [3H]GalNAcOH (N-acetylgalactosaminitol). Finally, the radioactive product was fragmented by periodate oxidation followed by alkaline elimination. The bulk of the radioactivity was associated with periodate-resistant oligosaccharides indicating that clusters of GlcUA-GalNAc-SO4 periods are often adjacent to a varying number of (n = 1-4) of L-IdUA-SO4-containing periods. 4. To study the distribution of L-IdUA-SO4-containing periods in relation to blocks of IdUA-GalNAc-SO4 periods different fractions of hyaluronidase-degraded dermatan sulphate were degraded separately. In all types of fragments (mol. wts. 1,500-10,000) L-IdUA-SO4-containing periods were demonstrated. In short fragments reducing terminal GalNAc-6-SO4 (6-sulphated N-acetylgalactosamine) was found confirming that these sequences were joined to relatively long D-GlcUA-containing block sequences via GalNAc-6-SO4. Moreover, low-molecular-weight oligosaccharides composed of alternating sequences were encountered. An octasaccharide derived from the carbohydrate sequence -GalNAc---GlcUA-GalNAc-IdUA-GalNAc-GlcUA-GalNAc-IdUA-GalNAc---GlcUA-GalNAc (--- indicates the position of cleavage by hyaluronidase) was identified.

Animals↗
PubMed1982

Co-polymeric glycosaminoglycans in transformed cells. Transformation-dependent changes in the co-polymeric structure of heparan sulphate.

1. Heparan sulphates from normal 3T3 fibroblasts are association-prone as indicated by their affinity for agarose gels substituted with cognate heparan sulphate species. Heparan sulphates from SV40-transformed or polyoma-virus-transformed cells have no affinity for the same gels. 2. Heparan sulphates from the medium, the pericellular and intracellular pools of normal, SV40-transformed and polyoma-transformed 3T3 cells were separated into four subfractions (HS1-HS4) by ion-exchange chromatography. In general, HS1-HS3 were found in cell-derived heparan sulphates, whereas HS3-HS4 were present in the medium. The heparan sulphates from transformed cells were more heterogeneous and of lower charge density than those from the normal counterpart. 3. Degradations via periodate oxidation/alkaline elimination yielded the oligomers glucosamine-(hexuronate-glucosamine)(n)-R with n=1-5 and a large proportion of N-sulphate groups. There was a large contribution of fragments n=4-5 from heparan sulphates of normal cells. These fragments were less common in low-sulphated heparan sulphates of transformed cells. In the case of medium-drived heparan sulphates all species had a low content of fragments n=4-5. 4. The size distribution of (glucuronate-N-acetylglucosamine)(n) regions was assessed after deaminative cleavage. It was broad and ranged from n=1-10 for all heparan sulphate species. In the case of medium-derived heparan sulphates there were distinct differences between normal and transformed cells. In the latter chains the N-acetyl-rich segments were both shorter and longer than in the normal case. The shape of the disaccharide peak was consistent with a lower content of O-sulphate in the heparan sulphates from transformed cells. 5. It was concluded that heparan sulphates from medium or transformed cells exhibit the greatest structural deviation from the normal case. The finding of lower proportions of extended, iduronate/glucuronate-bearing, N-sulphate-rich segments in heparan sulphates of transformed cells was particularly interesting in view of the fact that these elements have been associated with ability to self-interact.

Animals↗
PubMed1996

Early enteral feeding in postsurgical cancer patients. Fish oil structured lipid-based polymeric formula versus a standard polymeric formula.

OBJECTIVES: The authors compared the safety, gastrointestinal tolerance, and clinical efficacy of feeding an enteral diet containing a fish oil/medium-chain triglyceride structured lipid (FOSL-HN) versus an isonitrogenous, isocaloric formula (O-HN) in patients undergoing major abdominal surgery for upper gastrointestinal malignancies. SUMMARY BACKGROUND DATA: Previous studies suggest that feeding with n-3 fatty acids from fish oil can alter eicosanoid and cytokine production, yielding an improved immunocompetence and a reduced inflammatory response to injury. The use of n-3 fatty acids as a structured lipid can improve long-chain fatty acid absorption. METHODS: This prospective, blinded, randomized trial was conducted in 50 adult patients who were jejunally fed either FOSL-HN or O-HN for 7 days. Serum chemistries, hematology, urinalysis, gastrointestinal complications, liver and renal function, plasma and erythrocyte fatty acid analysis, urinary prostaglandins, and outcome parameters were measured at baseline and on day 7. Comparisons were made in 18 and 17 evaluable patients based a priori on the ability to reach a tube feeding rate of 40 mL/hour. RESULTS: Patients receiving FOSL-HN experienced no untoward side effects, significant incorporation of eicosapentaenoic acid into plasma and erythrocyte phospholipids, and a 50% decline in the total number of gastrointestinal complications and infections compared with patients given O-HN. The data strongly suggest improved liver and renal function during the postoperative period in the FOSL-HN group. CONCLUSION: Early enteral feeding with FOSL-HN was safe and well tolerated. Results suggest that the use of such a formula during the postoperative period may reduce the number of infections and gastrointestinal complications per patient, as well as improve renal and liver function through modulation of urinary prostaglandin levels. Additional clinical trials to fully quantify clinical benefits and optimize nutritional support with FOSL-HN should be undertaken.

Adolescent↗
PubMed1975

Interaction between polymeric materials and tissue -- biodeterioration of polymeric materials.

Styrene-isoprene block copolymer/methyl methacrylate graft copolymer (SIS-MMA), styrene-butadiene block copolymers (SBS), polyethylene, 1,2-polybutadiene, polysulfone, polycaprolactone polyurethane (PU) and ethylene-vinyl acetate copolymer (EVA) were implanted subcutaneously in dogs for 1 year. The same materials were stored in physiological saline solution at 37 degrees C (in vitro) and in air at room temperature (in air) for 1 year for comparative purpose. Biodeterioration or biodegradation of these materials was studied by mechanical property testing, viscometry, x-ray diffractometry, infrared spectroscopy and microscopy. A little deterioration of the mechanical properties of all the implanted samples was noticed as compared with the samples stored in vitro and in air. The infrared spectrum and x-ray diffraction pattern of the implanted sample except SIS-MMA were practically identical with the control. The implanted samples of SIS-MMA and SBS showed a cracked surface under a differential interference microscope. Viscosity measurements suggested a possible main chain scission for SIS-MMA and cross-linking for SBS and showed that the molecular weight of the other materials was almost unchanged. The intactness was rather surprising in regard to the infrared spectrum and viscosity of PU and EVA, because they were supposed to be more biodegradable. Deterioration of the mechanical properties was not always due to the results of biodegradation, as is often believed, but it must be considered that it might also be due to the absorption of some constituents such as lipids, steroids and amino acid from the body fluids and/or leaching of low molecular weight substances from the implanted materials.

Absorption↗