Isolation and characterizartion of alginic acid from commercially cultured Nemacystus decipiens (Itomozuku).
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An alginate was isolated from commercially cultured Nemacystus decipiens which had been harvested in Yonashiro Town (Okinawa, Japan). The yield of the alginate was 1.6% (w/w of wet alga), and the uronic acid, ash and moisture contents of the alginate were 86.0%, 12.0%, and 2.3% (w/w), respectively. The molecular mass of the alginate was estimated to be about 1.5 x 10(5). The infrared spectrum and optical rotation of the alginate were in agreement with those of the standard alginate. D-Mannuronic acid and L-guluronic acid were identified by 1H- and 13C-NMR spectroscopy, the molar ratio of both sugar residues being estimated to be 0.72:1.00. (+info)
Effects of high molecular weight hyaluronan on the distribution and movement of proteoglycan around chondrocytes cultured in alginate beads.
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OBJECTIVE: To evaluate the effects of high molecular weight hyaluronan (HA) on the distribution and movement of proteoglycan (PG) formed around rabbit chondrocytes cultured in alginate beads. DESIGN: Rooster comb-derived HA (MW 8x10(5) Da) was co-polymerized in alginate gel to study the direct effects of extrinsic HA on chondrocytes. PG metabolism of rabbit chondrocytes cultured in alginate beads was examined by measuring the incorporation of [(35)S]sulfate into glycosaminoglycan in two distinct regions, the cells with their cell-associated matrix (CM) and the further-removed matrix (FRM). Immunohistochemical analysis was performed using monoclonal antibodies against chondroitin sulfate and keratan sulfate. Autoradiography using degenerated cartilage tissue from the rabbit osteoarthritis (OA) model was performed to discover the effect of HA on the distribution of newly-synthesized PG in the cartilage tissue. RESULTS: The incorporation of [(35)S]sulfate into newly-synthesized PG in the cells with CM decreased with the addition of 0.125-1.0 mg/ml HA, while the incorporation in the FRM increased. These effects of HA on the distribution of newly-synthesized PG were the same either in chondrocytes with CM or chondrocytes without CM. Immunohistochemical analysis showed that staining of PG in the CM was decreased and staining in the FRM was increased in the HA treated group compared to the control group. Autoradiography using degenerated cartilage tissue from the rabbit OA model indicated that [(35)S]-labeled macromolecules showed a more diffuse distribution in the HA treated group compared with the control group. CONCLUSION: These results indicate that extrinsic HA could affect the movement of newly-synthesized PG from the CM to the FRM in both alginate beads and cartilage tissue. (+info)
Treponema parvum sp. nov., a small, glucoronic or galacturonic acid-dependent oral spirochaete from lesions of human periodontitis and acute necrotizing ulcerative gingivitis.
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Small oral spirochaetes with a strict dependence on either glucuronic acid (GluA) or galacturonic acid (GalA) were isolated from European patients with periodontitis and from Chinese patients with either gingivitis or acute necrotizing ulcerative gingivitis (ANUG). Thirteen such isolates were similar phenotypically to Treponema pectinovorum ATCC 33768T and this classification was confirmed by 16S rRNA sequencing. However, four isolates differed from T. pectinovorum by their small cell size, by a prominent beta-glucuronidase activity, by a distinct protein and antigen profile, by an inability to grow on pectin as sole source of carbohydrate and by a markedly enhanced growth rate when supplied with a second carbohydrate (L-arabinose, D-galactose, D-glucose, D-fructose, D-mannitol, D-mannose, pectin, D-ribose or D-xylose) in addition to the essential GluA/GalA. By 16S rRNA sequencing these four isolates clustered in the recently described phylotype 'Smibert-2'. T. pectinovorum (14 strains) and 'Smibert-2' (four isolates with beta-glucuronidase activity) could each be subdivided into two serotypes based on immunoblot reactivity with two mAbs. Representatives of the two groups, including T. pectinovorum ATCC 33768T, showed a 1:2:1-type periplasmic flagellar arrangement. 'Smibert-2' is described as a novel species, Treponema parvum sp. nov., with isolate OMZ 833T (= ATCC 700770T) proposed as the type strain and OMZ 842 (= ATCC 700773) as reference strain for a second serotype. (+info)
Cell encapsulation technology as a therapeutic strategy for CNS malignancies.
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Gene therapy using viral vectors has to date failed to reveal its definitive clinical usefulness. Cell encapsulation technology represents an alternative, nonviral approach for the delivery of biologically active compounds to tumors. This strategy involves the use of genetically engineered producer cells that secrete a protein with therapeutic potential. The cells are encapsulated in an immunoisolating material that makes them suitable for transplantation. The capsules, or bioreactors, permit the release of recombinant proteins that may assert their effects in the tumor microenvironment. During the last decades, there has been significant progress in the development of encapsulation technologies that comprise devices for both macro- and microencapsulation. The polysaccharide alginate is the most commonly used material for cell encapsulation and is well tolerated by various tissues. A wide spectrum of cells and tissues has been encapsulated and implanted, both in animals and humans, indicating the general applicability of this approach for both research and medical purposes, including CNS malignancies. Gliomas most frequently recur at the resection site. To provide local and sustained drug delivery, the bioreactors can be implanted in the brain parenchyma or in the ventricular system. The development of comprehensive analyses of geno- and phenotypic profiles of a tumor (genomics and proteomics) may provide new and important guidelines for choosing the optimal combination of bioreactors and recombinant proteins for therapeutic use. (+info)
Ocular hypotensive efficacy and safety of once daily carteolol alginate.
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BACKGROUND/AIM: Carteolol is a beta adrenoceptor antagonist used topically to reduce intraocular pressure, typically twice daily. In an effort to provide a once daily dosing regimen, carteolol was formulated with 1% alginic acid. The objective of this study was to evaluate the efficacy and safety of carteolol alginate solution in comparison with standard carteolol solution. METHODS: This was a double masked, parallel group, multicentre study. Patients with ocular hypertension or open angle glaucoma (n=235) were randomly assigned to receive either carteolol alginate once daily [corrected] or standard carteolol solution, twice daily. The masking was maintained through the use of a vehicle in the evening for the alginate group. Patients were evaluated at baseline, 15, 60, and 120 days. RESULTS: At 0900 (presumed trough) on day 60, mean reductions in intraocular pressure (IOP) from baseline were 6.09 (SD 2.97) and 6.09 (3.18) mm Hg for the standard carteolol and alginate, respectively. At 1100 (presumed peak), mean reductions were 6.51 (2.53) and 6.47 (2.76) mm Hg, respectively. Results were similar at other times (day 15 and day 120). The most common side effect was transient stinging on instillation of drops, which did not differ significantly between groups. There were no differences of note in other ocular or systemic signs or symptoms. CONCLUSION: The new alginate formulation of carteolol 2% given once daily was as effective as standard carteolol 2% given twice daily with no meaningful differences regarding safety. (+info)
Complete protection of islets against allorejection and autoimmunity by a simple barium-alginate membrane.
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We describe a new technique for microencapsulation with high-mannuronic acid (high-M) alginate crosslinked with BaCl(2) without a traditional permselective component, which allows the production of biocompatible capsules that allow prolonged survival of syngeneic and allogeneic transplanted islets in diabetic BALB/c and NOD mice for >350 days. The normalization of the glycemia in the transplanted mice was associated with normal glucose profiles in response to intravenous glucose tolerance tests. After explantation of the capsules, all mice became hyperglycemic, demonstrating the efficacy of the encapsulated islets. The retrieved capsules were free of cellular overgrowth and islets responded to glucose stimulation with a 5- to 10-fold increase of insulin secretion. Transfer of splenocytes isolated from transplanted NOD mice to NOD/SCID mice adoptively transferred diabetes, indicating that NOD recipients maintained islet-specific autoimmunity. In conclusion, we have developed a simple technique for microencapsulation that prolongs islet survival without immunosuppression, providing complete protection against allorejection and the recurrence of autoimmune diabetes. (+info)
Injectable gels for tissue engineering.
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Recently, tissue engineering approaches using injectable, in situ gel forming systems have been reported. In this review, the gelation processes and several injectable systems that exhibit in situ gel formation at physiological conditions are discussed. Applications of selected injectable systems (alginate, chitosan, hyaluronan, polyethylene oxide/polypropylene oxide) in tissue engineering are also described. Injectable polymer formulation can gel in vivo in response to temperature change (thermal gelation), pH change, ionic cross-linking, or solvent exchange. Kinetics of gelation is directly affected by its mechanism. Injectable formulations offer specific advantages over preformed scaffolds such as: possibility of a minimally invasive implantation, an ability to fill a desired shape, and easy incorporation of various therapeutic agents. Several factors need to be considered before an injectable gel can be selected as a candidate for tissue engineering applications. Apart from tissue-specific cell-matrix interactions, the following gel properties need to be considered: gelation kinetics, matrix resorption rate, possible toxicity of degradation products and their elimination routes, and finally possible interference of the gel matrix with histogenesis. (+info)
Effect of hydrophilic substances on liberation of quinidine from starch - alginate sphere.
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The effect of selected hydrophilic agents on the quinidine loading and its release from potato starch alginate spheres prepared by instilling viscous suspensions into a desolvation liquid (saturated calcium chloride: paraffin liquid: heptan 1:1:1 v/v/v) was studied. The loading of quinidine in spheres was 59.77%-46.30% and it depended on the presence of auxiliary hydrophillic agents such as polyethylene glycol 2000 (59.77%), polyoxyethylene - 20 - sorbitan monostearate (49.55%), glyceryl monostearate (49.02%), sorbitan monooleate (46.30%). The drug release from spheres was diffusion controlled in accordance with the Higuchi model. It was concluded that the release rate constants depended on the drug - carrier - hydrophilic agent composition and dissolution media. (+info)