Influence of various alginate brands on the redifferentiation of dedifferentiated bovine articular chondrocytes in alginate bead culture under high and low oxygen tension.

We examined the influence of various alginates on the redifferentiation of dedifferentiated articular chondrocytes in alginate bead culture under low (5%) and (21%) high oxygen supply. Isolated bovine articular chondrocytes were dedifferentiated and multiplied by 2-week monolayer culture under 21% oxygen. They were subcultured at a density of 10(7) cells/mL in six different commercially available sodium alginates (1.2%, w/v) and held under 21 or 5% oxygen for 3 weeks. Proliferation (DNA measurement on days 0 and 21 of culture), collagen type II production (immunocytochemistry and Western blotting), and [(3)H]proline and [(35)S]sulfate incorporation were monitored. Collagen type II production was significantly stronger under 5% oxygen compared with 21% oxygen in two alginates (three other alginates nearly reached the significance level). However, alginate-based differences proved not to be significant. [(3)H]Proline incorporation was not influenced by alginate but showed strong oxygen dependency (up to 3-fold higher under 5% oxygen). For [(35)S]sulfate incorporation oxygen dependency was even stronger (up to 8-fold higher under 5% oxygen) and significant alginate-dependent differences were found for several alginates. The effects of the different alginates did not correlate with their pH, viscosity, or guluronic:mannuronic acid ratio. Thus, the type of alginate and even more, the oxygen supply, influence the redifferentiation and matrix production of dedifferentiated bovine articular chondrocytes.

Production and characterization of alginate-starch-chitosan microparticles containing stigmasterol through the external ionic gelation technique

Stigmasterol - a plant sterol with several pharmacological activities - is susceptible to oxidation when exposed to air, a process enhanced by heat and humidity. In this context, microencapsulation is a way of preventing oxidation, allowing stigmasterol to be incorporated into various pharmaceutical forms while increasing its absorption. Microparticles were obtained using a blend of polymers of sodium alginate, starch and chitosan as the coating material through a one-stage process using the external gelation technique. Resultant microparticles were spherical, averaging 1.4 mm in size. Encapsulation efficiency was 90.42% and method yield 94.87%. The amount of stigmasterol in the oil recovered from microparticles was 9.97 mg/g. This technique proved feasible for the microencapsulation of stigmasterol.

O estigmasterol, um fitoesterol com diversas atividades farmacológicas, é suscetível à oxidação quando exposto ao ar, calor e umidade. Neste contexto, a microencapsulação é uma forma de proteção contra oxidação, permitindo a incorporação do estigmasterol em diversas formas farmacêuticas e aumentar sua absorção. As micropartículas foram obtidas por gelificação iônica externa, em uma etapa, utilizando como revestimento polímeros naturais de alginato de sódio, amido de milho e quitosana. As micropartículas apresentaram formato esférico com tamanho aproximado de 1,4 mm. O rendimento foi de 94,87% e a eficiência média de encapsulação de 90,42%. A quantidade de estigmasterol no óleo recuperado das micropartículas foi de 9,97 mg/g. O método mostrou-se viável para a microencapsulação do estigmasterol.

The influence of tray type and other variables on the palatal depth of casts made from irreversible hydrocolloid impressions.

STATEMENT OF PROBLEM: There are conflicting data regarding the effect of various factors on the palatal depth of casts made from irreversible hydrocolloid impressions. PURPOSE: This study examined the influence of tray type, water temperature, pouring technique, and stone expansion on the palatal depth of casts. MATERIAL AND METHODS: Irreversible hydrocolloid impressions were made of a model under simulated oral conditions. Palatal depth was measured relative to a reference plane with a microscope. The reference planes were standardized by subjecting the data to three 2-dimensional mathematic rotations. A 2-factor analysis of variance (alpha=.05) was used to determine whether differences existed among tray types and among palatal locations. RESULTS: The palatal depth of the casts increased approximately 0.06 mm compared with the master model with all but 2 variables. Statistical testing revealed that increased depth was not attributable to water temperature (52 degrees F or 72 degrees F) or tray type (custom resin, perforated metal, metal rimlock, or rimlock with built-up palate). Custom resin tray impressions poured with a lower expansion stone and perforated tray impressions inverted onto a base made from the same mix of stone resulted in casts with palatal depths most similar to that of the master model (P<.001). CONCLUSIONS: Casts with palatal contours of comparable accuracy were obtained with the use of a stock metal or customized tray and the use of differing water temperatures to mix the impression material.

TNF production from peripheral blood mononuclear cells in diabetic patients after stimulation with alginate and lipopolysaccharide.

Microencapsulated pancreatic Langerhans islets in calcium alginate gels have been used as an implantable bio-artificial pancreas in the treatment of diabetes mellitus, but with limited success due to overgrowth of the capsule with fibroblasts and phagocytes. The authors earlier demonstrated that alginates enriched in mannuronic acid stimulate human monocytes to produce high levels of cytokines such as tumour necrosis factor (TNF), IL-1 IL-6. In this study the authors have measured the TNF production from peripheral blood mononuclear cells (PBMC) in different groups of insulin-dependent diabetes mellitus (IDDM) patients after stimulation with different alginates and lipopolysaccharide (LPS). It was found that high G-alginate did not induce TNF production in any of the groups. High-M alginate and LPS induced a dose-dependent TNF production in all groups and the production was significantly different from unstimulated cells. The highest TNF response was found in newly diagnosed IDDM patients and the lowest was in the controls.

Influência de diferentes dosagens de pó, para três alginatos, na alteraçäo linear de modelos de gesso pedra / Influence of different water powder ratio, for three alginates, in stone models linear changes

Estudaram-se as alteraçöes lineares de modelos de gesso de pedra obtidos de moldes de três alginatos: Avagel (A), Hydrogum (H) e Jeltrate (J), em três diferentes modos de comparaçäo do pó: näo compactado (NC), suavemente compactado (SC) e fortemente compactado (FC). Foram feitas comparaçöes analisando-se a distância entre duas marcas de uma placa metálica; o gesso também foi usado como material de moldagem para ser avaliado quanto à sua influência no processo, dada sua expansäo normal de presa. Aceitando-se que a distância estudada exprressa o tamanho dos modelos e moldes de gesso, a análise estatística dos resultados permitiu concluir que: 1- os moldes de gesso sempre foram maiores que o original (expansäo média de 0,4 por cento); 2- os modelos provenientes dos três alginatos também apresentaram-se maiores; 3- dentre estes modelos, comparando-se aos moldes de gesso, a maioria apresentou semelhança, com a condiçäo JNC promovendo modelos maiores e ANC e HSC menores; 4- para um mesmo alginato, nas diferentes condiçöes, a maioria dos modelos apresentou diferenças entre si e 5- para a mesma condiçäo de compactaçäo, os modelos, em sua maioria, apresentaram diferençäas entre si; o Hydrogum, na condiçäo de suave compactaçäo originou modelos de dimensöes mais próximas do original

Tratamiento oclusivo con alginato de calcio en heridas infectadas / Obstetricia treatment with calcium alginate in infected wounds

Las heridas infectadas representan un problema quirúrgico serio, con implicacionmes ocupacionales y económicas. El uso de Alginato de Calcio en su tratamiento puede ser de gran ayuda para su curación. En nuestro estudio, noventa y tres pacientes con heridas infectadas, que requerían debridación y curas compresivas, fueron tratados con cura de alginato de calcio el cual fue bien tolerado, su retiro fue fácil sin causar dolor ni daño, reduciendo el número de curas oclusivas realizadas y su frecuencia así como mejorando la curación y cicatrización con efectos adversos mínimos