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PubMed1996

Oxygen diffusivity in calcium alginate gel beads containing Gluconobacter suboxydans.

Gaining insight into the mass transfer characteristics in immobilized enzyme and microorganism systems bears much importance because of their widely increased use in industrial scale production as well as for analysis purposes. In this study, the effective diffusion coefficient of oxygen in calcium alginate gel with and without cells has been determined by the Moment Analysis Method for the first time in literature. When the gel concentration was increased from 1 to 3 %, De values of oxygen varied between 2.54 x 10(-5) cm2/s and 2.58 x 10(-5) cm2/s indicating almost no dependency on gel concentration. However, a decrease in effective diffusion coefficient (from 2.55 cm2/s to 2.47 cm2/s) was observed with increased immobilized Gluconobacter suboxydans concentration in the range of 0 to 6 %. Experimental results on liquid-particle mass transfer coefficient revealed a negligible external mass transfer resistance. Effectiveness factor for the bioreactor system was also calculated and found to be 0.39 and 0.21 for gel beads of 0.1 and 0.2 cm radius respectively. It is concluded therefore that the use of smaller gel beads could substantially improve the production efficiency in similar bioreactors.

Acetobacteraceae↗
PubMed2003

Proteolysis, volatile compounds, and sensory evaluation in Hispánico cheese manufactured with the addition of a thermophilic adjunct culture, nisin, and calcium alginate-nisin microparticles.

Nisin, free or incorporated in calcium alginate microparticles, was added to pasteurized milk (80% cows' and 20% ewes' milk) used for the manufacture of Hispánico cheese with a mesophilic starter and a thermophilic adjunct culture of high aminopeptidase activity. Addition of nisin incorporated in microparticles promoted early lysis of thermophilic adjunct culture bacteria. Extracellular aminopeptidase activity in 1-d-old cheese made with both thermophilic adjunct culture and nisin incorporated in microparticles was 1.8-fold higher than in cheese made with thermophilic adjunct culture and free nisin and 2.0-fold higher than in cheese made only with thermophilic adjunct culture without any addition of nisin. Addition of nisin, free or incorporated in microparticles, did not influence cheese proteolysis measured using hydrophilic or hydrophobic peptides, o-phthaldialdehyde ripening index, or free amino acids. Moreover, a total of 37 volatile compounds were identified in the volatile fraction of Hispánico cheese, using a dynamic headspace technique with a purge and trap system followed by a gas chromatography mass spectrometry analysis. The volatile compound profile was not influenced by nisin addition, either free or incorporated in microparticles, but addition of thermophilic adjunct culture enhanced the formation of 2-butanone, diacetyl, 2,3-pentanedione and acetoin and improved the flavor quality (sensory panel) of cheese.

Alginates↗
PubMedDate not supplied

influence of concentration and mannuronate/guluronate [correction of gluronate] ratio on steady flow properties of alginate aqueous systems.

Steady flow properties were measured at various concentrations for aqueous systems of alignates with different mannuronate/gluronate (M/G) ratios using a cone-plate type rheometer. The flow curve (a plot of shear stress vs. shear rate) shows a plateau region, which is ascribed to a heterogeneous structure, at low shear rate. This plateau region is more noticeable in the G-rich systems than in the M-rich systems. On the other hand, the flow curves for the systems with the same molecular weight but different M/G ratios are congruent in the high shear rate region. The zero shear viscosity can be reduced by the segment contact parameter, cMw, for the alginates with the same M/G ratio but different molecular weights. The zero shear viscosity is proportional to cMw in a low concentration region and is proportional to (cMw)3.4 at relatively high concentrations. The critical value of cMw for which the zero shear viscosity changes from proportionality with cMw to proportionality with (cMw)3.4 is ca. 900.

Alginates↗
PubMed2006

Prospective, randomized, and active controlled study of the efficacy of alginic acid and antacid in the treatment of patients with endoscopy-negative reflux disease.

AIM: To assess the efficacy and safety of a compound containing alginic acid plus antacid (Topaal) compared to equal-strength antacid (Nacid) in patients with endoscopy-negative reflux disease (ENRD). METHODS: A total of 121 patients with ENRD were randomized to receive Topaal (65 patients) or Nacid (56 patients) for 6 weeks, with a consultation every 3 weeks. The primary end-point assessment was the change in the severity of heartburn as evaluated using a visual analog scale (VAS) at 6 weeks. The secondary end-point assessments were the VAS at 3 weeks, the change of frequency of the reflux symptom, the change of quality of life and the adverse effects. RESULTS: Demographics of randomized subjects in each treatment group were comparable except that the Topaal group included more males. The baseline characteristics between the groups were similar. After 6 weeks of treatment, the reduction of VAS of heartburn was more prominent in the Topaal group (-6.29 cm vs -4.11 cm). At the 3rd week, Topaal group showed greater reduction of VAS for heartburn (P=0.0016), regurgitation (P=0.0006), vomiting (P=0.0373), and belching (P<0.0001). The patients of the Topaal group had lower frequency of heartburn (P=0.0015) and pain (P=0.0163) at the end of the 6-week treatment period. From the doctor's point of view, the Topaal group also showed significant reduction in the severity of heartburn (P=0.0020), regurgitation (P=0.0081), vomiting (P=0.0182), and belching (P=0.0018) at the end of the treatment. The improvement of the quality of life was more remarkable in the Topaal group at the end of the 6-week treatment period (P<0.0001). For the adverse effect, there was no difference in both the groups. CONCLUSION: Topaal is more effective than Nacid for the treatment of symptoms presented by patients with ENRD.

Adult↗
PubMed1998

Factors affecting dimensional instability of alginate impressions during immersion in the fixing and disinfectant solutions.

To clarify the factors determining the dimensional stability of alginate impressions during immersion in disinfectant and fixing solution, the weight change of impressions in solutions of glutaraldehyde (GA), NaClO, Na2SO4, K2SO4, CaCl2, and ZnSO4 was measured. In the nonelectrolytic solution, GA, the weight decreased in proportion to concentration, possibly due to the gradient of osmotic pressure between the impression and solution. In monovalent metallic salt solutions the weight change decreased with increased concentration. Especially at lower concentrations the rate of weight loss was high. A chemical action of the solution might also be involved, in addition to the osmotic pressure difference. The weight loss in divalent metallic salt solutions was greater than in monovalent solutions, implicating crosslinking reactions between the impression and solution.

Alginates↗
PubMed2006

Antimicrobial effects of alginate-based film containing essential oils for the preservation of whole beef muscle.

Alginate-based edible films containing 1% (wt/vol) essential oils of Spanish oregano, Chinese cinnamon, or savory were immersed in 2% (wt/vol) or 20% (wt/vol) CaCl2 solution and then applied to beef muscle slices to control the growth of Escherichia coli O157:H7 and Salmonella Typhimurium. Whole beef muscle surfaces were inoculated with one of these strains at 10(3) CFU/cm2. During the 5 days of storage, samples of meat were obtained periodically for microbiological analysis. The availability of active compounds from essential oils present in films was evaluated by determination of total phenolic compounds for oregano- and savory-based films and of total aldehydes for cinnamon-based films during storage. After 5 days of storage, films containing oregano or cinnamon essential oils were the most effective against Salmonella Typhimurium regardless of the type of pretreatment used (2 or 20% CaCl2). During the same period, meat inoculated with E. coli O157:H7 and coated with films treated with 2% CaCl2 had significantly fewer bacteria (P < or = 0.05) when oregano-based films were used than when cinnamon- and savory-based films were used. The E. coli O157:H7 concentration was higher at the end of the storage period when films were pretreated with 20% CaCl2. Evaluation of the active compounds in films revealed that availability in oregano- and savory-based films was significantly more important (P < or = 0.05) than that in cinnamon-based films regardless of the type of pretreatment used (2 or 20% CaCl2). At the end of storage, release rates of 40, 60, and 77% were noted in oregano-, savory-, and cinnamon-based films in 2% CaCl2 and rates of 65, 62, and 90% were noted in the same films in 20% CaCl2.

Alginates↗
PubMed1998

A microbiological investigation following the disinfection of alginate and addition cured silicone rubber impression materials.

The antimicrobial efficacy of four commercially available disinfectants (Haz-tabs, chlorhexidine, Virkon and C&J Algisept Spray) was investigated. It was shown that all were effective in decontaminating the impressions whilst those placed only in sterile water, used as a control, showed variable levels of bacterial growth. Moreover, alginate appeared to carry significantly higher numbers of bacteria than addition cured silicone rubber.

Adult↗
PubMed1999

Biodegradable alginate microspheres as a delivery system for naked DNA.

Sodium alginate is a naturally occurring polysaccharide that can easily be polymerized into a solid matrix to form microspheres. These biodegradable microspheres were used to encapsulate plasmid DNA containing the bacterial beta-galactosidase (LacZ) gene under the control of either the cytomegalovirus (CMV) immediate-early promoter or the Rous sarcoma virus (RSV) early promoter. Mice inoculated orally with microspheres containing plasmid DNA expressed LacZ in the intestine, spleen and liver. Inoculation of mice with microspheres containing both the plasmid DNA and bovine adenovirus type 3 (BAd3) resulted in a significant increase in LacZ expression compared to those inoculated with microspheres containing only the plasmid DNA. Our results suggest that adenoviruses are capable of augumenting transgene expression by plasmid DNA both in vitro and in vivo.

3T3 Cells↗
PubMed1999

Evaluation of bioartificial pancreas function made from sodium alginate and poly-L-lisine microcapsules settled with viable pancreatic islets.

The possibility of transplantation of immuno-isolated viable pancreatic islets is a promising alternative for treatment diabetic patients. To establish the value of the artificial prosthesis made from settled with viable pancreatic islets microcapsulated using sodium alginate and poly-L-lisine, the glucose plasma levels were analyzed versus time after implantation into peritoneal cavity of rats or mice with alloxan-induced diabetes. The proper function of the bio-artificial pancreas manifested in normalization of glucose plasma level has been observed from 14 to 21 days after implantation in diabetic mice and rats.

Alginates↗
PubMed2000

Intranasal vaccination of New Zealand white rabbits against pasteurellosis, using alginate-encapsulated Pasteurella multocida toxin and potassium thiocyanate extract.

OBJECTIVE: We evaluated the efficacy of intranasal administration of Pasteurella multocida toxin (PMT) and a potassium thiocyanate extract of P. multocida (CN) encapsulated in alginate microspheres, compared with unencapsulated PMT and CN antigens, in protection of rabbits against pasteurellosis. METHODS: New Zealand male rabbits (n=24) were allotted randomly into four intranasally administered vaccine groups: 1, PMT/CN; 2, microencapsulated PMT/CN with or; 3, without subcutaneous priming; and 4, empty microspheres (control). Blood samples and nasal wash specimens were collected before vaccination and one week after each vaccination (days 7, 21, 35, and 49). Rabbits were primed subcutaneously with either unencapsulated PMT/CN or aluminum hydroxide (control) (day 0), vaccinated intranasally (days 14, 28, and 42), challenged intranasally with live P. multocida (day 56), and necropsied (day 60). RESULTS: Compared with controls, PMT/CN-immunized rabbits had significantly higher concentrations of serum IgG and IgM, nasal IgG, and bronchoalveolar lavage fluid IgA and IgG against CN. Immunized rabbits had 100% survival rate and low numbers of bacteria in liver and lungs; the control group had 50% survival rate and higher numbers of bacteria (> 4x) per gram of tissue in liver and lungs. CONCLUSION: The PMT/CN microspheres stimulated systemic and mucosal immune responses similar in effectiveness (protection) to those in response to unencapsulated PMT/CN administration.

Administration, Intranasal↗
PubMed2000

Changes in the metabolism of the microalga Chlorella vulgaris when coimmobilized in alginate with the nitrogen-fixing Phyllobacterium myrsinacearum.

In an agroindustrial wastewater pond, a naturally occurring unicellular microalga, Chlorella vulgaris, was closely associated with the terrestrial plant-associative N2-fixing bacterium Phyllobacterium myrsinacearum. When the two microorganisms were artificially coimmobilized in alginate beads, they shared the same internal bead cavities, and the production of five microalgal pigments increased, but there were no effects on the number of the cells or the biomass of the microalga. The association, however, reduces the ability of C. vulgaris to remove ammonium ions and phosphorus from water. The bacterium produced nitrate from ammonium in synthetic wastewater with or without the presence of the microalga, and fixed nitrogen in two culture media. Our results suggest that interactions between microalgae and associative bacteria should be considered when cultivating microalgae for wastewater treatment.

Alginates↗
PubMed2000

Synthesis of iron-crosslinked hydroxamated alginic acid and its in vitro evaluation as a potential matrix material for oral sustained-release beads.

Hydroxamated alginic acid (HAA) was prepared. The generated semisynthetic polymer was employed in the formation of drug-loaded, iron(III)-crosslinked polymeric beads. Infrared spectroscopy was employed to prove the crosslinking. The degree of hydroxamate substitution was determined by acid-base back titration, and it was found to be ca. 20%. The produced beads were evaluated in vitro as orally administered sustained release drug delivery system. Theophylline, paracetamol, and chlorpheniramine maleate were used as model drugs. The generated beads proved to be successful in prolonging drug release, particularly in the case of theophylline. Iron leaching from the generated beads was minimal (< 0.5% of the entire complexed iron), and took place during passage through the simulated gastric fluid.

Acetaminophen↗
PubMed2001

Ion exchange selectivities of calcium alginate gels for heavy metals.

An equilibrium model has been proposed and verified, based on the conditions in the gel phase and Donnan equilibrium theory, for the analysis of the experimental data on the recovery of lead, copper, cadmium, cobalt, nickel and zinc from synthetic, nonmetallic aqueous solutions on calcium alginate gels. This equilibrium model considers that the system behaves as an ion-exchange process between the calcium in the gels and the divalent metals in solution, and that the metallic portion enclosed in gel fluid is supposed an important quantitative contribution to the total amount of metal uptake by gels. According to the equilibrium constants calculated, it is deduced that the selectivity order is: Pb > Cu > Cd > Ni > Zn > Co.

Alginates↗
PubMedDate not supplied

Effect of hydrophilic substances on liberation of quinidine from starch - alginate sphere.

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.

Alginates↗
PubMedDate not supplied

[Treatment with sodium alginate of gastroesophageal reflux disease in childhood: efficacy and tolerance assessment].

OBJECTIVE: Evaluation of efficacy of sodium alginate (Gaviscon) in the treatment of gastroesophageal reflux disease in children 3-12 months old, assessed by 24 hours esophageal continuous pH monitoring. METHOD: 28 children studied by 24 hours pH esophageal continuous monitoring before starting the treatment with Gaviscon 0.5 ml/Kg/dose four times a day, 20 minutes after meal. After 2 months of treatment, a second pH esophageal monitoring was performed, during therapy. Total number of refluxes, number of refluxes longer than 5 minutes and reflux index before and during treatment were evaluated, by multiple regression method. RESULTS: All pHmetric parameters showed a statistically significative improvement after 60 days of treatment.

Alginates↗
PubMedDate not supplied

[Content of alginic acid and fucoidan in fucus algae of the Barents sea].

Seasonal changes in the content of alginic acid and fucoidan have been studied in four species of fucus algae from the Barents sea: Fucus vesiculosus, F. distichus, F. serratus, and Ascophyllum nodosum. These polysaccharides are accumulated in the biomass of the algae during summer and autumn. To ensure complete processing of fucus algae it is recommended that the raw material be harvested within this period.

Alginates↗
PubMedDate not supplied

Some effects of disinfecting solutions on the properties of alginate impression material and dental stone.

The study investigated the effect of two disinfecting solutions on one brand of alginate impression material and dental stone. Control impressions were immersed in water for equivalent periods and the effect of storage of impressions after disinfection or control immersion in water was also investigated. There were no significant dimensional changes in impressions poured after one hour. All impressions stored for 16 hours before pouring showed significant dimensional changes. Mixing dental stone with one disinfectant caused a significant softening of the cast. It is strongly recommended that all impressions are thoroughly rinsed with water after disinfection to prevent incorporation of disinfectant in the cast.

Alginates↗
PubMedDate not supplied

Effect of Chitosan and Sodium Alginate on the adherence of autochthonous C. Albicans to oral epithelial cells (in vitro).

The aim of the present study was to evaluate the effect of Heavy Molecular Weight Chitosan (HMWCh) and Sodium Alginate (NaAl) on fungal adherence. C albicans was identified and isolated from non-stimulated saliva extracted from male and female healthy adults. The minimum inhibitory concentration (MIC) was determined for each of the biopolymers. MIC values were 0.25 % (W/V) for HMWCh and 0.10 % (W/V) for NaAl. Fungal cell hydrophobicity was evaluated against xylene in the presence of HMWCh. Statistically significant differences between the control (without HMWCh) and the different HMWCh concentrations in fungal suspension were observed (P< 0.05). The fact that HMWCh and NaAl impaired fungal adherence to buccal epithelial cells (BEC) as compared to control revealed that polymers inhibit Candida albicans adherence to BEC (HMWCh and NaAl: P= 0.00001), NaAl being more effective than HMWCh (P = 0.00001). HMWCh dettached and aggregated C. albicans, including the fungi and BEC in the mesh. NaAl inhibited adherence, aggregated and entrapped the fungi in the mesh, excluding BEC. We may conclude that both biopolymers are effective. However, NaAl is a stronger inhibitor of adherence. Thus, in combination or alone, these biopolymers could be used in the treatment of oral candidosis.

Alginates↗