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PubMed1992

[Microbiological studies of self-disinfecting alginate impression materials].

Using microbiologically experimental methods and observations corresponding to praxis the efficiency of the addition of antiseptics to alginate is evaluated. The addition of chlorhexidine to the alginate leads to a considerable reduction of the amounts of germs, but an one hundred percent disinfection of the alginates is not always performed. An influence of the alginate materials and the water quality on the antimicrobial efficacy of chlorhexidine has been proved. The always occurring contamination of the impression tray rules out a complete stopping of infection between the patient and the laboratory staff.

Alginates↗
PubMed2003

[Experimental studies on adriamycin alginate-chitosan microcapsules in the treatment of rabbit VX2 carcinoma in the extremity].

OBJECTIVE: To study the effects of chemoembolization with adriamycin alginate-chitosan microcapsules in the treatment of VX2 carcinoma in the extremity of the rabbit. METHODS: Twenty-four New Zealand white rabbits transplanted with VX2 carcinoma cells into the muscle tissue of the lower right thigh were divided into four groups namely groups A, B, C and D, and received regional infusion from femoral artery. Each group consisted of six rabbits: a group given natural saline (Group A), a group given adriamycin (Group B), a group given blank alginate-chitosan microcapsules (Group C) and a group given adriamycin alginate-chitosan microcapsules (Group D). Three days after treatment, all groups were examined by histology and immunohistochemical detection (TdT-mediated dUTP nick end labeling technique, TUNEL; proliferating cell nuclear antigen, PCNA). RESULTS: The blood vessels of the tumor were almost embolized by the microcapsules. Extensive necrosis, high level of positive cells in TUNEL (60.85% +/- 5.21%) and low level in PCNA detection with in the tumors were observed in Group D. CONCLUSION: Adriamycin alginate-chitosan microcapsules can potentially play roles in two respects, 1 to serve as embolizing agents, and 2 to serve as drug delivery vehicles for local release. Chemoembolization with microparticals is an effective treatment of malignant osseous and soft tissue sarcomas in an experimental model.

Alginates↗
PubMed2003

A clinical evaluation of the agar alginate combined impression: dimensional accuracy of dies by new master crown technique.

PURPOSE: To evaluate the dimensional accuracy of several impression methods including agar alginate combined impression in vivo; the marginal accuracy of stone dies was determined using a new electroformed master crown technique. MATERIALS AND METHODS: Cast cores with knife-edge and chamfer margins and electroformed master crowns were fabricated for 3 patients. Five impressions were taken of each preparation, using agar alginate combined impression and silicone impression materials. Dies were made after impression. The marginal fit of the master crown on each die was analyzed by four-way analysis of variance (ANOVA) and Tukey HSD test (p<0.05). RESULTS: The marginal fit of the master crown on the dies with chamfer margin was better than those with knife-edge margin for agar alginate combined impression. The shape of the margin did not affect the accuracy when silicone impression material was used. CONCLUSIONS: The results suggest that the agar alginate impression method is clinically acceptable for the chamfer margin, but shape of the margin may affect the dimensional accuracy of dies. The shape of the margin does not affect the accuracy of dies when silicone impression was used. Furthermore, the master crown made by electroforming technique could be useful for clinical evaluation of impression methods.

Agar↗
PubMed1997

[High performance gel chromatographic behaviour of sodium alginate and determination of its molecular weight parameters].

The molecular weight parameters of sodium alginate were determined by high performance gel chromatography with Waters Bondagel E-High A column. The differences in high performance gel chromatographic behaviours between the sodium alginate and the non-polar standard Dextran T500 were compared. The influences of the sample concentration and the sample volume on the results were discussed. The high performance gel chromatographic behaviour of sodium alginate is different from that of Dextran T500, and is also different from those on Sepharose or Sephadex columns. The peak shifted toward full osmotic side under in crease of ionic strength. The elution volumn didn't tend toward stable, even though at the high concentration of 0.5mol/L NaCl. A change of the sample concentration at stable sample volume or the sample volume at stable sample concentration would cause tailing peaks. It was showed that the sample size of sodium alginate would be less than 25microg, and the relative standard deviations of Mn, Mw and d were 0.95%, 4.04% and 4.70%.

Alginates↗
PubMed1992

Mucosal immunity to Pseudomonas aeruginosa alginate in cystic fibrosis.

Patients with cystic fibrosis commonly acquire chronic pulmonary infection with alginate-producing Pseudomonas aeruginosa. The infection remains localized at the mucosal surfaces of the airways. Using enzyme-linked immunosorbent assays immunoglobulin concentrations and titers of specific antibodies to purified P. aeruginosa alginate and to P. aeruginosa sonicated antigens were measured in tears, saliva, sputum and serum. CF patients had significantly higher concentrations of IgG, IgA and SIgA in serum and saliva than controls. They also had significantly higher levels of specific antibodies to alginate and sonicated antigen in secretions and serum. Local production of IgA, IgG and IgM antibodies to P. aeruginosa was demonstrated. Only a minor proportion of specific IgA antibodies were present as secretory IgA in tears, saliva and sputum. The ratio of alginate-specific SIgA to specific monomeric IgA in sputum was significantly lower than the similar ratio in saliva, whereas the same ratio for specific P. aeruginosa sonicate antigens was found in saliva and sputum.

Adolescent↗
PubMed2005

Synthesis of zinc-crosslinked thiolated alginic acid beads and their in vitro evaluation as potential enteric delivery system with folic acid as model drug.

The aim of this study is to explore the potential of synthetic modifications of alginic acid as a method to enhance the stability of its complexes with divalent cations under physiological conditions. A fraction of algin's carboxylic acid moieties was substituted with thiol groups to different substitution degrees through conjugating alginate to cysteine to produce alginate-cysteine (AC) conjugates. Infrared spectrophotometry and iodometry were used to characterize the resulting polymeric conjugates in terms of structure and degree of substitution. Moreover, zinc ions were used to crosslink the resulting AC polymers. Folic acid loaded beads were prepared from Zinc-crosslinked AC polymers (AC-Zn) of different cysteine substitution degrees. The generated beads were then investigated in vitro for their capacity to modify folic acid release. AC-Zn polymeric beads resisted drug release under acidic conditions (pH 1.0). However, upon transfer to a phosphate buffer solution (pH 7.0) they released most of their contents almost immediately. This change in drug release behavior is most probably due to the sequestering of zinc cations by phosphate ions within the buffer solution to form insoluble chelates and, to a lesser extent, the ionization of the carboxylic acid and thiol moieties. Removal of zinc ions from the polymeric matrix seems to promote polymeric disintegration and subsequent drug release. A similar behavior is expected in vivo due to the presence of natural zinc sequestering agents in the intestinal fluids. AC-Zn polymers provided a novel approach for enteric drug delivery as drug release from these matrices complied with the USP specifications for enteric dosage forms.

Alginates↗
PubMed1991

[Refeeding after ingestion of diets containing 10% soybean protein associated with various concentrations of alginate or sodium carrageenan. Effects on growth and lipid parameters in the rat].

Male 21-d-old Wistar rats were fed over 3 experimental periods. During the first period of 4 wk, diets contained 10% casein or defatted soy flour proteins, with or without 0.5, 1, 2 or 3% sodium alginate or sodium carrageenan, and were heated. During the second period, they were fed a standard diet for 16 wk with 17% proteins, and during the third period, they received the same diet as in the first period, but with 20% proteins. Rat body weights were measured throughout the study period; plasma lipid levels were then determined after fasting. Presence of sodium alginate in the diet had no effect on growth, but rats fed carrageenan presented growth retardation at the end of the experimental period, which was not altered by refeeding the standard diet. Sodium alginate did not modify rat triglyceridemia, except at the 1% level. Carrageenan had a hypotriglyceridemic effect. Alginate and carrageenan had no effect on blood cholesterol. Compared to soybean protein, casein intake did not increase plasma cholesterol levels as generally described. The effect of carrageenans on growth and plasma triglyceride levels could be a result of their physico-chemical properties.

Alginates↗
PubMed1991

Suppression of radioactive strontium absorption by sodium alginate in animals and human subjects.

The effect of 23 sodium alginate preparations from different species of algae (Sargassum sp.) and kelp (Laminaria sp.) on reducing the absorption of strontium was studied in detail. A pilot production procedure has been established. Na alginate from S. siliquastrum was proven to be a potent agent for reducing Sr absorption, with high efficiency and virtually no toxicity. It reduced the body burden of strontium 3.3-4.2 fold in rats. Strontium absorption in human subjects was reduced by 78% (+/- 8.9) or completely suppressed the increase of serum Sr at 2 h after ingestion of stable Sr in volunteers and decrease 24 h urine Sr to similar extent. No undesirable effects on gastrointestinal function was observed nor were Ca, Fe, Cu and Zn metabolism changed, both in the animal experiments and in human. It was concluded that alginate preparations derived from Sargassum species are a suitable antidote against radiostrontium absorption on a long-term basis, when added to bread at a 6% level. In cases of emergency, an alginate syrup preparation appears to be more suitable because of its rapid action.

Alginates↗
PubMed1991

Experimental immunization with Pseudomonas aeruginosa alginate induces IgA and IgG antibody responses.

We tried experimentally to induce a specific antibody response against Pseudomonas aeruginosa locally in the airways and systemically in rats by three different routes of immunization; intragastric feeding, intratracheal inoculation or subcutaneous vaccination. Three groups of rats were immunized with live mucoid P. aeruginosa PAO 579 by intragastric feeding or with killed PAO 579 intratracheally or subcutaneously. Three other groups were immunized with purified P. aeruginosa alginate either by intragastric feeding, intratracheally or subcutaneously. At weekly intervals for four weeks animals were sacrificed and serum and bronchial fluid were obtained. The specific IgA and IgG antibody response in lavage fluid and serum was measured. Only traces of antibodies could be detected in the bronchial lavage fluids. Anti-alginate IgA and IgG antibodies developed in all rats immunized with alginate but no antibodies against other P. aeruginosa antigens were detected. The highest IgA and IgG titer against alginate was induced by the subcutaneous immunization. IgA and IgG antibodies against other P. aeruginosa antigens developed in rats immunized with liver and sonicated bacteria. The highest IgA and IgG titers were obtained after intratracheal and subcutaneous immunization with sonicated bacteria. The present work has shown that IgA and IgG antibodies develop with high specificity after immunization. The different titers obtained do not necessarily reflect different degrees of protection.

Alginates↗
PubMed1990

Treatment of childhood peptic oesophagitis with famotidine or alginate-antacid.

Both antacids and H2 receptor antagonists have a potential role in treating peptic oesophagitis associated with acid reflux. The aim of this study is to assess the efficacy and tolerability of famotidine and alginate-antacid in children with endoscopically documented peptic oesophagitis. We compared clinical, endoscopic and histological response to alginate-antacid (1 tablet to be chewed 30 min after each meal and at bed time) or famotidine (1 mg/kg before supper at 7 pm) in 49 children (mean age 9 years, 34 males). Twenty-four of them were randomly allocated to alginate-antacid treatment (group A), twenty-five to famotidine (group B). Both treatments were protracted for six months and endoscopy was then repeated. Symptoms disappeared in 43.4% and improved in 47.8% of children of group A and disappeared in 91.6% of those of group B (p less than .05). Mean time for symptom disappearance was 17 weeks for group A and 5 weeks for group B (p less than .01). After six months, at endoscopy oesophagitis was healed in 43.4% in group A and in 41.6% of group B, the difference between the two groups was not significant, however the improvement of endoscopic grades induced by famotidine was significantly better (p less than .05). Histology showed a healed peptic oesophagitis in 52.2% of the children in group A and in 70.8% of group B (p less than .001). No toxicity was observed with either treatment. We conclude that famotidine is superior to alginate-antacid in treating peptic oesophagitis associated with acid reflux, since it induces a better symptomatic response and a greater improvement of endoscopic lesions.

Adolescent↗
PubMed1990

[Angle reproducibility and surface roughness of stone casts obtained from combined agar-alginate impressions].

Angle reproducibility and surface roughness were compared among stone casts obtained from two agar-alginate impression methods; 1) conventional method in which an alginate mix was applied before gelation of agar, and 2) improved method in which an alginate mix was applied to gelled agar. Impressions of the rectangular parallel piped metal mold with a high accurate point angle was taken according to the above methods, and stone casts were obtained. Enlarged images of the angles of the casts were projected with an optical projector, and the defects of the point angle were traced. The area, the length and the circular-degree coefficient of the defects were determined using an image analysis system. The surface roughness of the stone casts was also measured. The stone casts prepared by the improved agar-alginate method had better angle reproducibility and the same surface roughness as that prepared by the conventional method.

Agar↗
PubMed1990

[Effects of alginates and sodium carrageenates mixed with soy proteins on the coefficient of protein efficiency].

Male 21 d-old Wistar rats, were fed for 4 wk with diets containing casein or soybean proteins (10%) with 0.5, 1, 2 or 3% sodium alginate or sodium carrageenan or without any alginate or carrageenan. Daily protein intake and weight gain of casein-fed rats were not significantly different (P less than 0.05) from those of rats fed soybean meal with alginate, whatever the dose received. Rats fed 3% carrageenan in soybean meal had significantly higher feed intake than that of rats fed casein. At the levels studied, alginate had no effect on the Protein Efficiency Ratio (PER), but carrageenan did. The addition of increased quantities of carrageenan to soybean meal followed by heating the mixture led to a progressive and significant decrease in PER at all levels of carrageenan compared to casein feeding. The addition of 3% carrageenan to heated soybean meal, corresponding to 0.62% of meal diet, led to a significant decrease in PER. These results confirm the precipitating role of carrageenans on proteins.

Alginates↗
PubMed1990

[Clinical evaluation of sodium alginate on oral mucositis associated with radiotherapy].

We evaluated the effect of sodium alginate on 39 patients with oral mucositis associated with radiotherapy. Sodium alginate was administered during radiotherapy to 17 patients with head and neck cancer. Compared with 22 patients without administration, sodium alginate reduced the pain and the erosion of oral mucosa significantly. Consequently the interval of radiotherapy was shortened. It is, therefore, expected that the effect of radiotherapy improves by the administration of sodium alginate.

Adult↗
PubMed1989

Surface quality of gypsums when poured against alginates.

Alginate impression materials are universally accepted for the fabrication of dental casts. Since casts reflect a direct link between the patient and the dentist, it is imperative that their surfaces be of highest quality. This study assesses the quality of dental cast surfaces when poured against alginate impression materials. A standardized system previously designed by the authors allowed the evaluations of 16 different gypsums poured against 32 different alginate surfaces, including a plexiglass control surface. Five hundred and twelve gypsum surfaces were produced and evaluated for quality in the following manner: 1) assessed visually with the aid of photomicrographs for surface smoothness; 2) evaluated by a modified Vickers scratch test for surface hardness. The results indicate that certain gypsum-alginate combinations provide superior surfaces with respect to hardness and smoothness, while other combinations suggest a high degree of incompatibility.

Alginates↗
PubMed1989

Calcium alginate, an aluminum-free phosphate binder, in patients on CAPD.

Since dialysis solutions in CAPD are now nearly aluminum free, the only source for elevated aluminum levels are aluminum-containing phosphate binders. Elimination with CAPD is insufficient to prevent aluminum accumulation. Therefore, we investigated a phosphate binder consisting of calcium alginate, a natural polyuronic acid, containing 100 mg calcium/g substance in 14 patients on CAPD over a period of one year. The patients had previously been treated with aluminum-containing phosphate binders for a period of 24.3 +/- 21.3 months. During a period of 3 weeks before changing to the new phosphate binder the mean (+/- SD) serum phosphorus concentration was 1.8 +/- 0.4 mmol/l, while at the end of one year of treatment with calcium alginate the concentration was 1.6 +/- 0.4 mmol/l. In order to lower serum phosphorus to this level, it was necessary to increase the mean (+/- SD) amount of calcium alginate from 6.9 +/- 1.3 g per day at the beginning of the study to 8.3 +/- 2.1 g per day at the end. The mean (+/- SD) serum calcium concentration did not change throughout the study period. Serum levels of alkaline phosphatase, 1.25 (OH)2 vitamin D3, and intact parathyroid hormone did not change as well. The mean (+/- SD) serum aluminum level declined from 36.0 +/- 20 to 14.0 +/- 11.3 micrograms/l after 6 months (p less than 0.001). In conclusion, calcium alginate is a good alternative to aluminum-containing phosphate binders and to phosphate binders on a calcium base as it does not lead to hypercalcemia. It prevents aluminum intoxication and has no serious side effects.

Alginates↗
PubMed1988

Radiolabelling patterns in alginate of Pseudomonas aeruginosa synthesized from specifically-labelled 14C-monosaccharide precursors.

Incorporations of radioactivity in alginate from specifically-radiolabelled glucose molecules by a parental strain and a gluconate-negative mutant of Pseudomonas aeruginosa were compared. The gluconate-negative mutant, which was deficient in the Entner Doudoroff pathway enzymes, produced less alginate than did the parental strain. The ratio of incorporation of radiolabel from [6-14C] versus [1-14C] glucose was 9.7:1 in the parental strain, implying that the carbon skeleton is catabolised via the Entner Doudoroff pathway. In comparison, a ratio of 1.5:1 was obtained for the mutant. Analysis of the alginate produced after growth on [6-14C] glucose showed that in both strains less radiolabel was present in carbon-6 of the constituent uronic acids than would be predicted (parental strain 8.4% and mutant 38.3% of the expected values). These results imply that TCA cycle intermediates are probably the major precursors of alginate in P. aeruginosa.

Alginates↗
PubMed1985

Alginate impression materials, dimensional stability and surface detail sharpness following treatment with disinfectant solutions.

A study was made of the influence of six dissimilar disinfectants on the dimensional stability and the surface detail sharpness of four alginate impression materials. All combinations of alginates and disinfectant solutions produced quite acceptable results as regards dimensional stability one hour after the impression material had been sprayed with the disinfectant. As regards surface detail sharpness one hour after this spraying certain combinations of alginates and disinfectant solutions showed better results than others. Immersion of the alginates in disinfectant solutions for one hour or more produced unacceptable changes.

Alginates↗
PubMed1970

Studies on inhibition of intestinal absorption of radioactive strontium. IX. Relationship between biological activity and electron microscopic appearance of alginic acid components.

The inhibitory action of alginate on intestinal absorption of radioactive strontium was investigated in order to correlate the biological activity with the chemical composition. Alginate from Laminaria hyperborea was partially hydrolyzed with oxalic acid and the degradation products were fractionated into polymannuronic and polyguluronic acid. The activity of these products was assessed biologically in rats and morphologically by electron microscopy. Sodium polymannuronate was found to be less effective than sodium polyguluronate in preventing absorption of radiostrontium. The inhibition of absorption of radio-calcium was low and not affected by hydrolysis or fractionation. When dried from dilute aqueous solutions, the polymannuronate retained the original helical structure of alginate, while the polyguluronate showed a strong tendency to coagulate, forming granules. The variation in the biological activity was attributed to the morphological differences between these alginic acid components and it is suggested that the degree of uncoiling of the polyguluronate chain in water is greater than that of the polymannuronate chain, thus making the carboxylate ions more accessible to strontium.

Alginates↗