Evaluation of self-prepared absorbable hemostatic cellulose fibrils / 浙江大学学报·医学版

To evaluate the effectiveness and safety of self-prepared absorbable hemostatic fibrils.A kind of absorbable hemostatic fibrils were prepared by self-developed patent technique. The physical form and molecular structure of the fibrils and a marketed product Surgicel were characterized by general observation and infrared spectroscopy; the carboxyl content, pH value and relative molecular mass of fibrils were determined by potentiometric titration method, pH meter and copper ethylenediamine method, respectively. The behavior of the fibrils and Surgicel in contact with blood was observed by inverted microscope, the cytotoxicity was evaluated by agarose diffusion cell assay . The external iliac artery hemorrhage model and the back muscle infiltration model in rats were established. The hemostatic effectiveness of the fibrils was investigated by hemostasis time and blood weight, and the degradation and biosafety of fibrils were investigated by observation photography, immune organ weighing, hematology and coagulation index measuring, and histopathological examination. The fibrils and Surgicel had similar molecular structures. Compared with the raw material regenerated cellulose, the typical carboxyl stretching vibration absorption peak of -COOH appeared near in both fibrils and Surgicel. The carboxyl content of the two materials was about 20%, and the pH value was about 3. The relative molecular mass of the fibers after oxidation was 4466±79, which was close to that of Surgicel(>0.05). After contacting with blood, the volume of fibrils and Surgicel expanded, and absorbed blood of dozens of times as their own weight. The results of agar diffusion test showed that the fibrils had no cytotoxicity. The results of animal experiments showed that the hemostasis completed within and there was no significant difference in blood weight and speed of hemostasis between two products (both >0.05). The fibrils could be degraded 1 week after being implanted to the bleeding sites of the muscle. There were no pathological effects on the appearance, body weight, food intake, immunological tissue thymus, spleen, lymph nodes, hematology and coagulation indexes of the rats, and no obvious abnormality found in the histopathological examination. The prepared absorbable hemostatic fibrils have excellent biological safety and effectiveness.

Pine nanocellulose and bacterial nanocellulose dressings are similar in the treatment of second-degree burn? experimental study in rats / Os curativos de nanocelulose de pinus e nanocelulose bacteriana são semelhantes no tratamento da queimadura de segundo grau? estudo experimental em ratos

ABSTRACT Background: Despite all the advances in medicine and the wide variety of dressings available, the treatment of burn wounds still represents an important medical challenge. The pinus cellulose membrane dressing is a biomaterial with characteristics similar to those of bacterial cellulose, but with lower cost. Aim: To evaluate the efficacy of pinus nanocellulose membrane on healing of deep second degree burns in rats and compare with Membracel®. Method: Thirty male Wistar rats were submitted to deep second degree burn in dorse, with boiling water at 97o C for 20 s, generating a 314 mm² area wound. The animals were distributed in three dressing groups (n=10): group 1 - simple gauze; group 2 - bacterial cellulose membrane (Membracel®); and group 3 - pinus cellulose membrane. They were evaluated for 20 days to verify clinical condition, macro and microscopic appearance and wound contraction. Results: All of them remained clinically well with no differences in weight. Crusts were observed in group 1, and none in groups 2 and 3. Regarding to scar contraction, groups 2 and 3 were similar, better than group 1. Microscopic analysis showed predominance of advanced healing degree in groups 1 and 3, and initial in group 2. Mature collagen was predominant in all groups. Conclusion: The pinus nanocellulose membrane is effective in the treatment of experimental second degree burn in rats and its effectiveness is similar to that of the bacterial nanocellular membrane.

RESUMO Racional: Apesar de todos os avanços da medicina e da grande variedade de curativos disponíveis, o tratamento das queimaduras ainda representa importante desafio médico. O curativo de membrana de celulose de pinus é biomaterial com características semelhantes à de celulose bacteriana, mas de menor custo. Objetivo: Avaliar a eficácia da membrana de nanocelulose de pinus na cicatrização de queimaduras profundas de segundo grau em ratos e comparar com a Membracel®. Método: Trinta ratos Wistar machos foram submetidos à queimadura profunda de segundo grau em dorso, com água fervente a 97o C por 20 s, gerando lesão de 314 mm². Os animais foram distribuídos em três grupos de curativos (n = 10): grupo 1 - gaze simples; grupo 2 - membrana de celulose bacteriana (Membracel®); e grupo 3 - membrana de celulose de pinus. Eles foram avaliados por 20 dias para verificar o quadro clínico, aspecto macro e microscópico e a contração da ferida. Resultados: Todos permaneceram clinicamente bem, sem diferenças de peso. Crostas foram observadas no grupo 1 e nenhuma nos grupos 2 e 3. Em relação à contração da cicatriz, os grupos 2 e 3 foram semelhantes, melhores que o grupo 1. A análise microscópica mostrou predomínio de grau de cicatrização avançado nos grupos 1 e 3, e inicial no grupo 2. O colágeno maduro foi predominante em todos os grupos. Conclusão: A membrana de nanocelulose de pinus é eficaz no tratamento de queimaduras experimentais de segundo grau em ratos e sua eficácia é semelhante à da membrana nanocelular bacteriana.

A new material to prevent urethral damage after implantation of artificial devices: an experimental study

ABSTRACT Objective To validate the application of the bacterial cellulose (BC) membrane as a protecting barrier to the urethra. Materials and Methods Forty female Wistar rats (four groups of 10): Group 1 (sham), the urethra was dissected as in previous groups and nothing applied around; Group 2, received a 0.7cm strip of the BC applied around the urethra just below the bladder neck; Group 3, received a silicon strip with the same dimensions as in group 2; Group 4, had a combination of 2 and 3 groups being the silicon strip applied over the cellulosic material. Half of the animals in each group were killed at 4 and 8 months. Bladder and urethra were fixed in formalin for histological analysis. Results Inflammatory infiltrates were more intense at 4 months at lymphonodes (80% Grade 2), statistically different in the group 2 compared with groups 1 (p=0.0044) and 3 (p=0.0154). At 8 months, all samples were classified as grade 1 indicating a less intense inflammatory reaction in all groups. In group 2, at 8 months, there was a reduction in epithelial thickness (30±1μm) when com-pared to groups 1 (p=0.0001) and 3 (p<0.0001). Angiogenesis was present in groups 2 and 4 and absent in group 3. In BC implant, at 4 and 8 months, it was significant when comparing groups 4 with 1 (p=0.0159). Conclusion BC membrane was well integrated to the urethral wall promoting tissue remodeling and strengthening based on morphometric and histological results and may be a future option to prevent urethral damage.

Biocompatibility of the bacterial cellulose hydrogel in subcutaneous tissue of rabbits

PURPOSE: To evaluate the biocompatibility and local sensibility reaction to bacterial cellulose hydrogel (0.8%) implanted in subcutaneous tissue of rabbits. METHODS: Fifteen New Zeland rabbits were randomly allocated into three groups: T1, 7 days, T2, 21 days, and T3, 84 days. The new material was implanted in the subcutaneous tissue of the ear; on the scalp over the periosteum; and on the outer and inner surfaces of the thighs, in the aponeurosis of the muscle. At 7, 21 and 84 postoperative days, the material was collected for histological study. The clinical signs, inflammatory response, angiogenesis and fibrogenesis were variables used for analysis of the biocompatibility and biological reactivity to BCH. Analyses were performed with an AXIO(r) Imager. The statistical tests were performed using the GraphPad Prism 5.0 program(r) RESULTS: The intensity of the inflammatory infiltrate, considering the different cell types (PMN, LMN and GC), was statistically significant, with group T1 different from groups T2 and T3 (p = 0.0124 and p <0.0001, respectively) and T2 different from the T3 group (p = 0.0007). Fibrogenesis grade 1 was the most prevalent in groups T1 (55.4%) and T2 (44.6%). The formation of neovascularization in the group was identified in 84.4% of samples. CONCLUSION: Bacterial cellulose hydrogel (0.8%) is biocompatible, integrating with the subcutaneous tissue of rabbits and inducing tissue remodeling. .

Evaluation of hollocelulase production by Lentinula edodes (Berk.) Pegler during the submerged fermentation growth using RSM / Avaliação da produção de enzimas holocelulolíticas por Lentinula edodes (Berk.) Pegler durante o crescimento em fermentação submersa usando MSR

The cellulase proteins have a great importance in the enzymatic hydrolysis of woody biomass. Despite of costs being a major concern, it has been a stimulus to study basidiomycetes biochemical properties which degrade lignocellulosic material and have prompted the processes' study for obtaining cellulolytic enzymes in fungi. The objective of this research was to evaluate the effects of the initial nitrogen content on (ammonium sulfate) and on sugar cane bagasse, which hereby, acts as an inducer of hydrolytic enzymes to produce cellulases and xylanases, using three Lentinula edodes (Berk.) Pegler strains as a transformation agent. A factorial design with 22 replications in the central point was conducted, varying concentrations of ammonium sulfate and sugar cane bagasse. The submerged cultures carried out in synthetic culture medium and incubated at 25°C for 7 days on an orbital shaker at 150 rpm. The total protein and cellulase activity as endoglucanase, exoglucanase and β-glucosidase and the xylanase was also determined. The results showed that the production of hydrolytic enzymes was stimulated by the presence of high concentrations of sugar cane bagasse (30g/L), characterizing it as an inducer due to the demonstrated proportional relationship. Thus, ammonium sulfate acted as a reducing agent in the synthesis of enzymes, being the low concentrations (0.1g/L) indicated for the enzyme production system under study. Among the studied strains, the EF52 showed higher activity for xylanase, endoglucanases, β-glucosidase and also protein.

As celulases são proteínas de grande importância na hidrólise enzimática de biomassa florestal. No entanto, seu custo elevado tem estimulado o estudo de processos de obtenção de enzimas celulolíticas por fungos filamentosos, tais como os basidiomicetos que apresentam propriedades bioquímicas para degradação de material lignocelulósico. O objetivo deste trabalho foi avaliar os efeitos do teor inicial de nitrogênio (sulfato de amônia) e de um indutor de enzimas hidrolíticas (bagaço de cana de açúcar) na produção de xilanases e celulases utilizando três isolados de Lentinula edodes (Berk.) Pegler como agente de transformação. Foi realizado um planejamento fatorial 22 com repetição no ponto central, variando as concentrações de sulfato de amônia e bagaço de cana de açúcar. O cultivo submerso realizado em meio de cultivo sintético e incubado a 25°C por 7 dias em agitador orbital a 150 rpm. Foram determinados o teor de proteínas totais e a atividade de celulase como: endoglucanase, exoglucanase e β-glucosidase e ainda xilanase. Os resultados demonstraram que a produção das enzimas hidrolíticas foi estimulada pela presença de alta concentração de bagaço de cana (30g/L), caracterizando-o como agente indutor devido à relação de proporcionalidade demonstrada. Por sua vez, o sulfato de amônio atuou como redutor da síntese de enzimas, sendo as baixas concentrações (0,1g/L) indicadas para o sistema de produção das enzimas em estudo. Quanto às linhagens, a EF52 mostrou maior atividade para xilanase, endoglucanases, β-glucosidase e proteínas.

Functionality of innovative and generic celluloses in metronidazole formulations / Funcionalidade de celuloses inovadores e genéricos em formulações de metronidazol

The wide variety of excipients available calls for evaluation of their functionality, in this case of the pharmaceutical performance of microcrystalline celluloses and sodium cross-linked carboxymethylcelluloses from different sources. This evaluation includes parameters such as powder flow, compactibility, ejection pressure and dissolution from fast-release tablets as well as from floating granules and controlled-release tablets. In a previous study, the excipient Carmacel® presented better disintegration properties compared to Croscarmellose®. However, the evaluation showed better compactibility performance for Croscarmellose®. These characteristics were observed using pure excipients. Nevertheless, these advantages have not been confirmed in tests employing immediate-release or modified-release formulations containing metronidazole. Regarding microcrystalline celluloses, the present comparative evaluation between pure Alfacel ® types 101 and 102 and pure Avicel® types 101 and 102 showed better compactibility performance for the latter. However, for metronidazole formulations, this advantage was not evident in the innovative excipient. Notwithstanding, this study revealed better compactibility performance of microcrystalline cellulose type 101. In terms of powder flow properties, Avicel® and Alfacel® showed similar performance. However, the results revealed better powder flow employing microcrystalline cellulose type 102 for both excipients. Based on the results obtained, it can be concluded that the employment of innovative and generic excipients have both advantages and disadvantages. The observed differences however, tend to disappear as the excipients are diluted in a formulation, thereby equalizing their influence on product performance.

A variedade de excipientes disponível no mercado requer adequada seleção desses no que se refere à sua funcionalidade, como no caso de celuloses microcristalinas (Avicel® 101 e 102 e Alfacel® 101 e 102) e de carboximetilceluloses de sódio reticuladas (Croscarmellose® e Carmacel®), provenientes de diferentes fontes. Assim sendo, o desempenho farmacotécnico desses excipientes deve ser avaliado quanto ao fluxo e característica de compactação do pó, à pressão de expulsão do núcleo, ao perfil de dissolução de comprimidos de liberação imediata e modificada assim como de grânulos flutuantes. Em um trabalho anterior, o excipiente Carmacel® apresentou melhores propriedades de desintegração quando comparado ao Croscarmellose®, porém, no que se refere à característica de compactação a avaliação revelou melhor desempenho para o Croscarmellose®. Tais características foram observadas empregando apenas os excipientes. Porém, tais vantagens não foram confirmadas nos ensaios empregando as formulações de liberação imediata ou de liberação modificada contendo metronidazol. No que se refere às celuloses microcristalinas, a avaliação comparativa entre Alfacel® puro dos tipos 101 e 102 e Avicel® puro dos tipos 101 e 102 revelou melhor desempenho desse último quanto à característica de compactação, no entanto, para as formulações contendo metronidazol não foi possível demonstrar tal vantagem para o excipiente inovador. Porém, o estudo revelou melhor desempenho quanto à característica de compactação da celulose microcristalina do tipo 101. Quanto às propriedades relativas ao fluxo de pó, o Avicel® e o Alfacel® apresentaram desempenho semelhante. Porém, o estudo revelou melhor fluxo de pó no emprego da celulose microcristalina do tipo 102, para ambos os excipientes. Considerando os resultados obtidos, pode-se concluir que o emprego dos excipientes inovador e genérico apresentam vantagens e desvantagens. No entanto, as diferenças observadas tendem a desaparecer em função da diluição desses na formulação, equalizando, dessa forma, sua influência no desempenho do produto.

Preparo e caracterização de micropartículas de acetobutirato decelulose e poli(3-hidroxibutirato) contendo piroxicam / Preparation and characterization of cellulose acetate butyrate and poly(3-hydroxybutyrate) microparticles containing piroxicam

O objetivo deste trabalho foi avaliar a influência da massa molar do acetobutirato de celulose (ABC) e da adição de poli(3-hidroxibutirato) [PHB] sobre amorfologia das micropartículas, a eficiência de encapsulação e os perfis de liberação do piroxicam. As micropartículas foram preparadas por meio da técnica de emulsão/evaporação do solvente O/A e caracterizadas quanto à morfologia por microscopia eletrônica de varredura. O teor de fármaco nas micropartículas foi determinado utilizando o método de espectrofotometria de absorção na região do ultravioleta; os ensaios de liberação realizados, utilizando tampão fosfato pH 6,8. As micropartículas obtidas apresentaram formas irregulares, e aquelas preparadas a partir do ABC com maior massa molar apresentaram maior tamanho. Mediante planejamento fatorial, observou-se que as variáveis analisadas(massa molar do ABC e adição de PHB) não influenciaram a eficiência de encapsulação do piroxicam, mas exerceram influência sobre a quantidade inicial de piroxicam liberada a partir das micropartículas.

This work aims to evaluate the influence of the cellulose acetate butyrate (CAB) molar weight and the additionof poly(3-hydroxybutyrate) [PHB] on microparticle morphology, encapsulation efficiency and release profile of piroxicam. The microparticles were prepared using the O/Wemulsion/solvent evaporation technique and characterized according to the morphologyusing scanning electron microscopy. The drug content in the microparticles was determined through UV spectrophotometry and a dissolution assay was conducted usingphosphate buffer pH 6.8. The obtained microparticles presented irregular shape; the ones prepared with CAB with large molar weight presented a larger size. Through a factorial design, it was observed that the analyzed variables (CAB molar weight and PHB addition)did not influence the encapsulation efficiency, but did influence the initial release of piroxicam from the microparticles.

Mecanismos generales de cesión de principios activos a partir de matrices monolíticas hidrofílicas preparadas con éteres de celulosa / Overall mechanisms that rule the active pharmaceutical ingredient’s delivery process from hydrophilic matrices elaborated with ether cellulose

Las matrices hidrofílicas son uno de los sistemas de liberación controlados más empleados a escala mundial. El reconocido éxito global de este tipo de sistemas está ligado a su manufactura por medio de tecnología convencional para la obtención de comprimidos, además de su bajo costo. Estos sistemas han sido objeto de investigación desde hace ya algunas décadas, mediante el uso de técnicas como la creación de imágenes a partir de resonancia magnética, calorimetría de barrido diferencial y la espectroscopia dieléctrica de baja frecuencia, entre otras. Varios autores han estudiado los diferentes estados del agua dentro de una matriz, así como el estado y los cambios en los estados de los materiales en el tiempo, con el fin de estudiar los mecanismos de cesión de los activos a partir de las matrices, así como para buscar modelos matemáticos que describan la evolución de la concentración en el tiempo. En la actualidad se cuenta con modelos matemáticos de gran utilidad que permiten identificar dichos mecanismos a partir de un análisis de los parámetros de los modelos y que conducen finalmente a predecir la velocidad de liberación a partir de estos sistemas.

The hydrophilic matrices are one of the most used controlled delivery systems in the world, due to the simple technology and low cost. A number of publications, over the last decades, have reported investigations in regard with the mechanisms of drug release from hydrophilic matrices. Nevertheless, the mechanisms of drug release from these systems continue to be a matter of debate. Differential scanning calorimetry, low frequency dielectric spectroscopy and nuclear magnetic resonance have been used to examine the distribution of water within ether cellulose matrices, as well as to describe the state of the materials inside the device. The objective is to study the release and hydration rate of hydrophilic matrices in order to contribute to the rationalization of the design of these controlled release systems through mathematical modeling and to obtain a better knowledge of the processes that occur during the release of the drug.

Avaliação da influência de adjuvantes não-poliméricos solúveis na liberação do nimodipino a partir de formulações matriciais de liberação prolongada / Evaluation of soluble non-polymeric adjuvants in the release of nimodipino from controlled release matrices formulations

Fármacos com características lipofílicas costumam apresentar velocidade de difusão muito baixa a partir de matrizes hidrofílicas de liberação, comprometendo a obtenção de níveis plasmáticos terapeuticamente efetivos. Contudo, a liberação de fármacos lipossolúveis a partir de sistemas matriciais é influenciada pelo pH do meio, que pode facilitar a formação de cargas na molécula, melhorando sua performance. O objetivo deste trabalho foi avaliar a capacidade de adjuvantes não poliméricos em facilitar a solubilização do Nimodipino, “in vitro”, através do perfil de dissolução de cápsulas matriciais de hidroxipropilmetilcelulose (HPMC). As formulações desenvolvidas apresentaram o mecanismo de liberação do fármaco pela matriz governado pelo processo de erosão de acordo com o modelo cinético de Korsmeyer-Peppas, onde n>1. Entretanto algumas formulações apresentaram 0.5> n < 1 demonstrando ser um sistema anômalo dependente de difusão e erosão. Os perfis de dissolução nos dois meios testados mostraram-se distintos podendo observar diferenças significativas entre eles.

Drugs with slow solubility present very low diffusion from hydrophilic matrices, committing the serum levels therapeutically effectives. However, the liberation of lipophilic drugs starting from matrix systems is influenced by the pH of the medium, that it can facilitate the formation of charges in the molecule, improving your performance. The objective of this work was to evaluate the capacity of non-polymeric excipients in facilitating the solubilization of Nimodipino “in vitro”, through the capsules dissolution profiles of hydroxypropylmethylcellulose matrices. The developed formulations presented the release mechanism of drug influenced by erosion process according with the kinetic model of Korsmeyer-Peppas, where n>1. However, some formulations presented 0.5> n <1 demonstrating to be an anomalous system dependent of diffusion and erosion. The dissolution profiles in the two tested mediums showed different, allowing to observe significant differences among them.

Effect of aqueous leaf extract of Irvingia gabonensis on gastrointestinal tract in rodents.

Effect of the aqueous leaf extract of I. gabonensis on the gastrointestinal tract was investigated on isolated rabbit jejunum, guinea pig ileum, gastrointestinal motility, castor oil-induced diarrhoea in mice and castor oil-induced fluid accumulation in rats. The results showed that the extract exhibited a concentration-dependent relaxation of spontaneous pendular movement of isolated rabbit jejunum and guinea pig ileum, and attenuated both acetylcholine-induced contraction of rabbit jejunum and histamine-induced contraction of guinea pig ileum. The extract (100, 200 and 400 mg/kg) also caused a significant dose-dependent decrease of gastrointestinal motility in mice (40.12, 39.45 and 37.45%), intestinal fluid accumulation in rats (71.43, 81.63 and 83.27%), and remarkably protected mice against castor oil-induced diarrhoea [58.33, 75 and 91.67% (Di Carlo score)] respectively. Preliminary phytochemical screening of the aqueous leaf extract of I. gabonensis revealed the presence of saponins, tannins, phenols and phlobatanins.

Efeito da fibra do polissacarídeo de soja no peso e na umidade das fezes de ratos em fase de crescimento / The effect of soy polysaccharide fiber on fecal weight and humidity in growing rats

OBJETIVO: Comparar, em ratos, o efeito do polissacarídeo de soja em relação a celulose e fórmula de soja sem fibra alimentar sobre o peso e a umidade fecal. MÉTODOS: Foram utilizados 12 ratos Wistar machos, com 21 dias de vida, distribuídos em três grupos, que receberam ração AIN-93G variando-se a fonte de fibra alimentar: grupo polissacarídeo, com 5 por cento de fibra na forma de polissacarídeo de soja; grupo fórmula de soja, com 5 por cento de fórmula de soja sem fibra; e grupo celulose, com 5 por cento de fibra na forma de celulose. As fezes foram coletadas em três períodos de 72 horas iniciados no 7º, 17º e 27º dia. As mesmas foram pesadas frescas e após secagem em estufa a 105 ºC até peso constante. A umidade foi calculada usando a fórmula [(peso fecal úmido - peso fecal seco)/peso fecal úmido] x 100. RESULTADOS: As somas do peso fecal úmido nos grupos polissacarídeo, fórmula de soja e celulose foram, respectivamente: 17,372±4,743 g; 6,045±0,619 g; 16,012±2,600 g (p = 0,001), observando-se diferença estatisticamente significante dos grupos celulose e polissacarídeo em relação ao grupo fórmula de soja. Não houve diferença estatisticamente significante entre os grupos celulose e polissacarídeo. Para o peso seco, na mesma ordem, observou-se: 6,463±1,177 g; 2,909±0,277 g; 10,068±1,085 g (p < 0,001), com diferença estatisticamente significante entre todos os grupos. CONCLUSAO: Os animais que receberam fórmula de soja apresentaram peso fecal úmido e seco inferior ao dos outros dois grupos, enquanto o polissacarídeo de soja determinou umidade fecal superior à da celulose, provavelmente por maior fermentação no cólon.

Sugar-cane juice induces pectin lyase and polygalacturonase in "Penicillium griseoroseum"

The use of other inducers as substitutes for pectin was studied aiming to reduce the production costs of pectin enzymes. The effects of sugar-cane juice on the production of pectin lyase (PL) and polygalacturonase (PG) by "Penicillium griseoroseum" were investigatedd. The Fungus was cultured in a mineral medium (ph 6.3) in a rotary shaker (150 rpm) for 48 h at 25§C. Culture media were supplemented with yeast extract and sucrose or sugar-cane juice. Sugar-cane juice added singly to the medium promoted higher PL activity and mycelical dry weight when compared to pectin and the use of sugar-cane juice and yeast extract or pectin. The results indicated that were similar to those obtained with sucrose-yeast extractor pectin. The results indicated that, even at low concentrations, sugar-cane juice was capable of inducing pectin lyase and polygalacturonase with no cellulase activity in "P. griseoroseum".

Accion de la celulosa microcristalina en la gastritis alcalina por reflujo biliar / Action of the microcrystalline cellulose in the alkaline gastritis due to bile reflux

Los ácidos biliares presentes en el contenido gástrico, productos de un reflujo duodeno gástrico han sido incriminados como responsables de agredir la mucosa gástrica mediante una acción detergente sobre la barrera defensiva. Esta acción nociva determina una lesión inflamatoria en dicha mucosa, constituyendo una gastritis crónica que se expresa clínicamente por dolor epigástrico pirosis y vómitos de aspecto biliosos entre otros síntomas, lo que ha constituido una entidad clínica llamada Gastritis Alcalina por Reflujo Duodenogástrico, más recientemente, Gastritis Reactiva según el Sistema Sydney. Las fibras dietéticas, más especialmente la celulosa, se han señalado como las más activas en la capacitación e inactivación de los ácidos biliares en recientes investigaciónes, lo que constituye una acción citoprotectora sobre la mucosa del estómago en los pacientes que presentan esta patología. En relación con estos conocimientos hemos realizado un estudio en 50 pacientes con gastritis alcalina diagnosticados por estudio endoscópico, dosificación de àcidos biliares totales en contenido gástrico y biopsia (excluyendo los pacientes con presencia de H. pylori); los cuales fueron divididos en 2 grupos de 25 cada uno, siendo tratados, el primer grupo (A) con almidón de maíz en polvo y el segundo grupo (B) con celulosa microcristalina en polvo a la dosis de 5 gramas diarios durante 3 meses observándose los seguientes resultados: los ácidos biliares totales en contenido gástrico disminuyeron al final del tratamiento de una forma mayoritaria en los pacientes tratados con microcelulosa, aunque no fue estadísticamente significativa. Desde el punto de vista clínico, hubo una respuesta altamente satisfactoria en el dolor, vómitos y pirosis al tratamiento con microcelulosa. Los signos endoscópicos inflamatorios localizados en la región antral y difusamente en toda la mucosa del estómago, mejoraron cuantitativamente, observándose, diferencia significativa en la localización antral. Los hallazgos histológicos al final del tratamiento, en el grupo A y en el grupo B no mostraron variaciones evolutivas en el estudio comparativo de las lesiones encontradas al inicio del tratamiento. Los resultados se muestran en tablas.

Transcriptional control of the cellulase genes in Trichoderma reesei

The expression of the cellulase transcripts of Trichoderma reesei is controlled by the nature of the energy carbon sources used in the culture medium. Cellulose and the soluble disaccharide sophorose, but not glycerol or glucose, act as inducers. Evidence is presented suggesting that a low constitutive extracellular cellulolytic system catalyzes the formation of a soluble inducer from cellulose, and this inducer triggers the expression of the cellulase transcripts. This basal and cellulose-induced expression of the cellobiohydrolase I mRNAs (cbh1), the major member of the cellulase system, is transcriptionally controlled by two independent cis-acting DNA regions. In addition, expression of the cbh1 transcript is influenced by the physiological state of the mitochondria and this sensitivity is controlled through the 5,-flanking DNA sequence of this gene.

Ethylcellulose as a carrier for controlled-release acetaminophen tablets

In this study ethylcellulose was evaluated as a carrier for preparation of prolonged release acetaminophen tablets. Solid dispersions containing three levels of ethylcellulose and acetaminophen (1:3; 1:1; 3:1) were prepared by the solvent method. Also physical mixtures at the same level of ethylcellulose and acetaminophen were prepared. Systems composed of solid dispersion or physical mixture containing the equivalent weight of 50 mg acetaminophen, Emcompress as diluent and 1 per cent magnesium stearate as lubricant were compressed into tablets and tested for dissolution. The dissolution data showed that the drug release decreased as the level of ethylcellulose increased in the solid dispersion formulations. The drug release from tablets prepared with solid dispersion followed the diffusion controlled model for inert porous matrix, while the drug release from tablets prepared with physical mixture followed the first-order kinetic model

Nutrient interaction in relation to glycaemic and insulinaemic response.

Although it is known that protein, fat and fibre reduce the postprandial glycaemia following an oral carbohydrate load, the nature and extent of interaction of different nutrients with one another in this respect is not well understood. The present study was designed to explore systematically the glycaemic and insulinaemic response to glucose (G) alone, or in combination with one or more of the following: casein (CS), maize oil (MO), cellulose (CL) and pectin (P). Besides 100 g G, eleven isoenergetic and six isocarbohydrate meals were studied on healthy adult males using an incomplete block design. Addition of other nutrients to G led to a lowering of the glycaemic response. The lowest glycaemic responses were seen in case of meals containing the largest number of nutrients. P was more effective in reducing postprandial glycaemia than CL. As in case of glycaemic response, low insulinaemic responses were also associated with P-containing meals, and meals containing the largest number of nutrients. But unlike in case of glycaemic response, there was a tendency for elevation of the insulinaemic response in case of CL-containing meals. The degree of attenuation of glycaemic response observed with meals containing several nutrients was roughly predictable on the basis of the attenuation observed with meals in which only one nutrient had been added at a time to G. But the glycaemic response of natural foods is unlikely to be predictable on the basis of their nutrient composition because of the overriding influence of several other factors such as physical form, cooking, processing, storage and antinutrient content of the food.