Regulating the structure of bacterial cellulose by altering the expression of bcsD using CRISPR/dCas9 / 生物工程学报

Gluconacetobacter xylinus is a primary strain producing bacterial cellulose (BC). In G. xylinus, BcsD is a subunit of cellulose synthase and is participated in the assembly process of BC. A series of G. xylinus with different expression levels of the bcsD gene were obtained by using the CRISPR/dCas9 technique. Analysis of the structural characteristics of BC showed that the crystallinity and porosity of BC changed with the expression of bcsD. The porosity varied from 59.95%-84.05%, and the crystallinity varied from 74.26%-93.75%, while the yield of BC did not decrease significantly upon changing the expression levels of bcsD. The results showed that the porosity of bacterial cellulose significantly increased, while the crystallinity was positively correlated with the expression of bcsD, when the expression level of bcsD was below 55.34%. By altering the expression level of the bcsD gene, obtaining BC with different structures but stable yield through a one-step fermentation of G. xylinus was achieved.

Desarrollo de cobertura y su evaluación en el tratamiento de las heridas crónicas / Desenvolvimento de cobertura e sua avaliação no tratamento de feridas crônicas / Development of coverage and its evaluation in the treatment of chronic wounds

Objective. To describe the development of the bacterial cellulose coating with anti-inflammatory Ibuprofen (BC/Ibu) and to evaluate the cicatrization process with its use in patients with chronic wounds of venous and diabetic etiology. Methods. Longitudinal descriptive study. The cellulose membrane, cultivated with bacteria Gluconacetobacter xylinus and with incorporation of Ibuprofen, was used in the treatment of patients with chronic wounds in public health services in a Brazilian municipality. The ideal coverage characteristics were evaluated through physical, chemical and cell proliferation tests. Results. The sample consisted of 14 patients (10 women and 4 men), 8 with venous ulcer, 5 with diabetic foot and one with mixed wound. There was reduction of area and pain in 9 lesions; total healing of 3 wounds; and debridement of the devitalized tissue in 5 wounds with increased area. The use of the membrane was important in the reduction of pain, exudation and ease in the accomplishment of the curative. Conclusion. BC/Ibu favored the cicatrization process of patients with chronic vasculogenic wounds.(AU)

Objetivo. Describir el desarrollo de la cobertura de celulosa bacteriana con antiinflamatorio Ibuprofeno (CB/Ibu) y evaluar el proceso de cicatrización en la utilización en pacientes con heridas crónicas de etiología venosa y diabética. Métodos. Estudio descriptivo longitudinal. La membrana de celulosa, cultivada con bacterias Gluconacetobacter xylinus y con incorporación del Ibuprofeno se utilizó en el tratamiento de pacientes con heridas crónicas en servicios de atención pública de un municipio brasileño. Se evaluaron características de cobertura ideal mediante pruebas físicas, químicas y de proliferación celular. Resultados. La muestra fue constituida por 14 pacientes (10 mujeres y 4 hombres): 8 con úlcera venosa, 5 con pie diabético y uno con herida mixta. Se redujo el área y el dolor en 9 lesiones; la cicatrización total de 3 heridas; y el debridamiento del tejido desvitalizado en 5 heridas con aumento del área. El uso de la membrana de celulosa disminuyó el dolor de la exudación y facilitó la realización del vendaje. Conclusión. La CB/Ibu favoreció el proceso de cicatrización de los pacientes con heridas crónicas vasculogénicas.(AU)

Objetivo. Descrever o desenvolvimento da cobertura de celulose bacteriana com anti-inflamatório Ibuprofeno (CB/Ibu) e avaliar o processo de cicatrização com a sua utilização em pacientes com feridas crônicas de etiologia venosa e diabética. Métodos. Estudo descritivo longitudinal. A membrana de celulose, cultivada com bactérias Gluconacetobacter xylinus e com incorporação do Ibuprofeno, foi utilizada no tratamento de pacientes com feridas crônicas em serviços de atendimento público de um município brasileiro. Foram avaliadas as características de cobertura ideal mediante testes físicos, químicos e de proliferação celular. Resultados. A amostra foi constituída por 14 pacientes (10 mulheres e 4 homens), sendo 8 com úlcera venosa, 5 com pé diabético e um com ferida mista. Houve redução da área e da dor em 9 lesões; cicatrização total de 3 feridas; e o debridamento do tecido desvitalizado em 5 feridas com aumento da área. O uso da membrana além da diminuição da dor, da exsudação e facilidade na realização do curativo. Conclusão. A CB/Ibu favoreceu o processo cicatrização dos pacientes com feridas crônicas vasculogênicas. (AU)

Bacterial cellulose and bacterial cellulose/polycaprolactone composite as tissue substitutes in rabbits' cornea / Celulose bacteriana e composto de celulose bacteriana/policaprolactone para substituto tissular na córnea de coelho

In order to test the performance of bacterial cellulose/polycaprolactone composite (BC/PCL) and pure bacterial cellulose (BC) as tissue substitutes in rabbits' cornea, a superficial ulcer containing 5mm in diameter and 0.2mm deep was made in the right cornea of 36 rabbits, then a interlayer pocket was created from the basis of this ulcer. Twelve rabbits received BC/PCL membrane and 12 were treated with BC membranes, both membranes with 8mm in diameter. The remaining rabbits received no membrane constituting the control group. The animals were clinically followed up for 45 days. Three animals of each group were euthanized at three, seven, 21, and 45 days after implantation for histological examination of the cornea along with the implant. Clinical observation revealed signs of moderate inflammatory process, decreasing from day 20th in the implanted groups. Histology showed absence of epithelium on the membranes, fibroplasia close to the implants, lymph inflammatory infiltrate with giant cells, collagen disorganization, with a predominance of immature collagen fibers in both groups with implants. Although inflammatory response is acceptable, the membranes used does not satisfactorily played the role of tissue substitute for the cornea during the study period.(AU)

Com objetivo de testar o desempenho do compósito celulose bacteriana/policaprolactona (CB/PCL) e da celulose bacteriana pura (CB) como substitutos teciduais em córnea de coelhos, foi realizada uma úlcera superficial de 5 mm de diâmetro e 0,2 mm de profundidade na córnea direita de 36 coelhos, criando-se um bolso interlamelar a partir da base dessa úlcera. Doze animais receberam a membrana do compósito CB/PCL e 12 foram tratados com membranas de CB, ambas com 8 mm de diâmetro, os coelhos restantes não receberam nenhuma membrana, constituindo o grupo controle. Os animais foram acompanhados clinicamente até 45 dias. Três animais de cada grupo sofreram eutanásia aos três, sete, 21 e 45 dias após o implante das membranas para análise histológica da córnea juntamente com o implante. À observação clínica, houve sinais de processo inflamatório moderado, diminuindo a partir do 20º dia nos grupos implantados. A histologia demonstrou ausência de epitélio sobre as membranas, fibroplasia próxima aos implantes, infiltrado inflamatório linfo-histiocitário com células gigantes, desorganização do colágeno, com predominância de fibras imaturas de colágeno em ambos os grupos com implantes. Embora a resposta inflamatória seja aceitável, as membranas utilizadas não desempenharam satisfatoriamente o papel de substituto tecidual para a córnea, no período estudado.(AU)

Minerals consumption by Acetobacter xylinum on cultivation medium on coconut water

The objective of this work is to verifying the consume of the minerals K, Na, Fe, Mg, P, S-SO4-2,B,N Total Kjedahl (NTK), NO3--N, and NH4+-N in the production of bacterial cellulose by Acetobacter xylinum, according to the medium and the manner of cultivation. The fermentative process was in ripe and green coconut water. K and Na were determined by flame emission photometry, Mg and Fe by atomic absorption spectrophotometry, P by molecular absorption spectrophotometry, S-SO4-2 by barium sulphate turbidimetry, B by Azomethin-H method, NTK by Kjeldahl method, N-NO3-and N-NH4+ by vapor distillation with magnesium oxide and Devarda's alloy, respectively. In Fermentation of ripe coconut water there were higher consumption of K (69%), Fe (84,3%), P (97,4%), S-SO2-2 (64,9%), B (56,1%), N-NO3 (94,7%) and N-NH4+ (95,2%), whereas coconut water of green fruit the most consumed ions were Na (94,5%), Mg (67,7%) and NTK (56,6%). The cultivation under agitation showed higher mineral consumption. The higher bacterial cellulose production, 6 g.L-1, was verified in the coconut water fermentative in ripe fruit, added KH2PO4, FeSO4 and NaH2PO4 kept under agitation.

Produção de biofilme (membrana de biocelulose) por Gluconacetobacter xylinus em meio de resíduos de frutas e folhas de chá verde / Biofilm production (biocellulose membrane), production by Gluconacetobacter xylinus in fruits residues and green tea medium

A biomembrana, que é uma membrana de celulose bacteriana (C6H10O5)n formada na superfície do meio de cultivo durante a fermentação acética, foi obtida através do cultivo associado de Gluconacetobacter xylinus (formalmente Acetobacter xylinum) e Saccharomyces cerevisiae em meio de folhas de chá verde, resíduos de frutas (abacaxi, mamão, laranja), resíduos de vegetais (beterraba), vinho e colágeno em condições estáticas a 28 ± 2°C de 7 a 30 dias de cultivo. Foi incorporado à biomembrana, extrato hidroalcoólico de Calendula officinalis, devido as suas propriedades anti-inflamatórias, antioxidantes e cicatrizantes. A espessura, o diâmetro e o peso da biomembrana foram mensurados e foram calculados a produtividade, bem como o fator de conversão de açúcar em celulose. A caracterização da biomembrana foi realizada por Differential Scanning Calorimetric, espectroscopia infravermelho, Brunauer-Emmett-Teller, resistência à tração e alongamento, microscopia eletrônica (Escola Politécnica - USP) e difração de raio-X. Através destas análises verificou-se que a biomembrana obtida nos diferentes meios de cultivo é composta por celulose, o tamanho médio dos poros variou de 517,9 a 1582,0 nm, a resistência à tração variou de 0,76 a 4,32 kN/m e o índice de cristalinidade entre 75% e 91%, a espessura da biomembranas variou de 0,16 a 6,38 mm. Foram realizados 576 experimentos, a maior produtividade (8,23 g de celulose/dia) foi atingida no meio de mamão com suco de laranja (suco de mamão: 50% v/v e suco de laranja: 19% v/v) em 7 dias de cultivo. O maior fator de conversão (2,36 g celulose/g de açúcar) foi obtido no meio de chá verde em 25 dias de cultivo. A adição de 1,5% p/v de colágeno ao meio de chá verde dobrou a massa da biomembrana. A incorporação do extrato de calêndula aumentou a flexibilidade, a cristalinidade e as propriedades mecânicas da biomembrana de chá verde

The biomembrane, cellulose membrane (C6H10O5)n formed in medium surface, was obtained from an associate culture Gluconacetobacter xylinus (formally Acetobacter xylinum) and Saccharomyces cerevisiae in green tea leaves, fruit residues (pineapple, papaya, orange), vegetables residues (beet), wine and collagen media in static condition , at 28 ± 2 ºC in 7 - 30 days cultivation. The Calendula officinalis hydroalcoholic extract was incorporated in the Biomembrane, due to its anti-inflammatory, anti-oxidants and cicatrizing proprieties. The biomembrane thickness, diameter and weight were measured. The productivity and conversion factor from cellulose to sugar were calculated. The biomembrane caracterization was performed by Differential Scanning Calorimetric, infrared spectroscopy, Brunauer-Emmett-Teller, resistance to tension, elongation, eletrocnic microscopy and raio-X difraction. In these analyses were verified that biomembrane obtained in different media were composed by cellulose, average porous size varied from 517.9 to 1582.0 nm, the resistance to tension varied from 0.76 to 4.32 kN/m and cristalinity index varied from 75% to 91%. The biomembrane thickness varied from 0,16 to 6,38 mm. It was performed 596 tests, the highest bacterial cellulose yield (8.23 ± 0.58 g cellulose/day) was obtained in papaya with orange (papaya juice: 50% v/v and orange juice: 19% v/v) in 7 cultivation days. The highest conversion factor (2,36 g cellulose/g sugar) was obtained in green tea medium in 25 days. The addition of 1.5% w/v collagen to the green tea media increased 2 times the biomembrane weight. The biomembrane absorption capacity for water and Marigold hydroalcoholic extract (1:1), were from 1.73 to 22 and, from 1.75 to 24 times dry weight, respectively. The Marigold extract improved the green tea biomembrane flexibility, cristalinity, and physical proprieties

Efecto de la sacarosa en la producción de celulosa por Gluconacetobacter xylinus en cultivo estático / Effect of sucrose in the production of cellulose by Gluconacetobacter xylinus in static culture

Objetivo. Determinar el efecto de sacarosa en la productividad de BC por Gluconacetobacter xylinus IFO 13693 en condición estática. Materiales y métodos. La síntesis de celulosa bacteriana (BC) por Gluconacetobacter xylinus se llevo a cabo en un cultivo estático discontinuo a temperatura ambiente, en presencia de sacarosa como la principal fuente de carbono a concentraciones iniciales de 0.8 a 7.6 % (p/v). Las concentraciones remanentes de BC, sacarosa, glucosa y fructosa se determinaron cada semana. Para la cinética de la hidrólisis de la sacarosa y formación de celulosa y el coeficiente de rendimiento del producto se utilizo el software Microcal Origin 6.0®. Resultados. En la cuarta semana los valores de BC se encontraron entre 32.5 a 39.5 g/L para las diferentes concentraciones de sacarosa. La cinética para la hidrólisis de sacarosa se ajusta al modelo de Michaelis-Menten, con una Vmax de 0.0002 mol L-1 h-1 y Km de 0.018 M. La producción de BC se ajusta al modelo propuesto por Marx-Figini y Pion, con un valor de la pendiente (kc), entre 0.0018 y 0.0024 h-1 para las diferentes concentraciones iniciales de sacarosa. Los coeficientes de rendimiento tienen valores de 0.8 a 2.4 g de BC producida/g de sacarosa consumida. Conclusiones. La hidrólisis de sacarosa, el consumo de glucosa y fructosa se refleja en la síntesis de celulosa. La hidrólisis de sacarosa y la producción de BC se ajustan a los modelos de Michaelis-Menten y al propuesto por Marx-Figini y Pion, respectivamente. Finalmente, el rendimiento depende de la concentración de sacarosa.

Objective. Determine the effect of sucrose on the productivity of BC by Gluconacetobacter xylinus IFO 13693 in static condition. Materials and methods. The synthesis of bacterial cellulose (BC) by Gluconacetobacter xylinus was carried out in a discontinuous static culture at room temperature, in the presence of sucrose as the main carbon source at initial concentrations of 0.8 to 7.6% (p/v). The residual concentrations of BC, sucrose, glucose and fructose were measured every week. The Microcal Origin 6.0®. Software used to determine the kinetics of hydrolysis of sucrose and formation of cellulose and the coefficient of performance of the product Results. In the fourth week the BC values were between 32.5 to 39.5 g/L for the different concentrations of sucrose. The kinetics for the hydrolysis of sucrose fits the Michaelis-Menten model, with a Vmax of 0.0002 mol L-1 h-1 and Km of 0.018 M. The production of BC follows the model proposed by Marx-Figini and Pion, with a value of the slope (kc) between 0.0018 and 0.0024 h-1 for different initial concentrations of sucrose. The yield coefficients have values of 0.8 to 2.4 g of BC produced / g of sucrose consumed. Conclusions. The hydrolysis of sucrose, fructose consumption and glucose is reflected in cellulose synthesis. The hydrolysis of sucrose and production of BC fit the Michaelis-Menten model and the model proposed by Marx-Figini and Pion, respectively. Finally, the performance depends on the concentration of sucrose.

Preparation for and study on the property of medical bacterial cellulose / 生物医学工程学杂志

Bacterial cellulose (BC) was prepared by Acetobacter xylinum in static culture. After purified by chemical treatment, the microstructure, chemical structure, crystal structure and mechanical property of BC were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD) and tensile strength measurement respectively, and compared with those of the imported bacterial cellulose wound dressing served as control sample (XBC). The results indicated that the diameter of the BC was (22 +/- 9) nm, and the crystallinity index was 89.71%. The tensile strength and the Young's mouduls of BC were significant higher than XBC both in wet and dry states. The biocompatibility of BC and XBC were evaluated by cytotoxicity test, delayed contact sensitization study in the Guinea Pig and skin irritation test. The results showed that BC had reliable biocompatibility as well as XBC. With the unique nanostructure, high crystallinity, high mechanical strength, and reliable biocompatibility, BC produced in our country as well as XBC can be used as a safe biomaterial for the medical applications.

Biotechnological production of cellulose by gluconacetobacter xylinus from agricultural waste

The purpose of this study was to utilize low quality date syrup, a rich and available source of nutrient in Iran, for the production of bacterial cellulose using Gluconacetobacter xylinus. Static batch fermentation for the purpose of cellulose production by G. xylinus [PTCC, 1734] was studied using low quality date syrup and sucrose solution [Bx. 10%] as fermentation media at 28°C. Results showed that maximum yields of bacterial cellulose after 336 h fermentation were 4.35 and 1.69 g/100 ml of date syrup and sucrose media, respectively. The FT-IR spectrum of commercial plant cellulose as a standard was similar to that of bacterial cellulose. To determine the physical structure of the bacterial cellulose and standard cellulose fibers, scanning electron microscopy [SEM] was carried out. The results revealed more delicacy in structure of bacterial cellulose. Determination of crystallinity of the samples using X-ray diffractometry demonstrated that the crystallinity level of standard cellulose [83.61%] was more than that of bacterial cellulose [60.73%]. This study obviously showed the ability of low quality date syrup, a suitable and cheap carbon source, to be used as a substrate in a fermentation medium for production of cellulose by Gluconacetobacter xylinus

Fechamento de perfuração septal nasal em coelhos com celulose bacteriana / Nasal septal perforation closure with bacterial cellulose in rabbits

Biomateriais podem ser válidos à somação de tecido e estrutura para o fechamento da perfuração do septo nasal. OBJETIVO: Testar celulose produzida pela bactéria Acetobacter xylinum associada à cola biológica no fechamento de perfurações septais em coelhos. Comparar histologicamente fibrose, inflamação, congestão vascular, integridade do enxerto e fechamento da perfuração septal. MATERIAL E MÉTODO: Quinze coelhos foram distribuídos em dois grupos: Controle (5 coelhos) e celulose - Bionext® associado à cola de fibrina - Tissucol® (10 coelhos). Foi realizada uma perfuração cirúrgica no septo nasal em todos os coelhos. Nos animais do grupo Bionext® foi realizado o fechamento da perfuração com a colocação de celulose e aplicação de cola de fibrina. RESULTADOS: Dois coelhos foram a óbito. No grupo com celulose ocorreu o fechamento de duas perfurações e em 4 casos a celulose manteve-se impactada entre os bordos das perfurações. No grupo controle não ocorreu fechamento da perfuração septal em nenhum dos coelhos operados. CONCLUSÃO: Não houve diferença estatística significante nos quesitos inflamação aguda, congestão vascular e fibrose, avaliado histologicamente. Nos casos onde o enxerto se manteve posicionado, não houve alteração quanto à sua integridade. Pode ser útil à somação do arsenal terapêutico como base para re-epitelização dos bordos da perfuração.

Alloplastic materials can be used together with tissue and structure to close nasal septal perforation. AIM: to test cellulose use in the closure of septal perforation in rabbits and to compare fibrosis, inflammation, vascular congestion and graft integrity. MATERIALS AND METHODS: Fifteen rabbits. The rabbits were divided into two groups: Control: Five rabbits and Bionext® and fibrin glue Tissucol®: Ten rabbits. Septal perforations were done in all of them. In the Bionext® group the closure was performed with the placement of cellulose. RESULTS: Two rabbits died in the first week. Cellulose group: 2 closures without the cellulose in between the septum membrane and in 4 cases the graft stood in the middle of the perforation locked in place by the edges. No closure in the control group. CONCLUSION: There was no closure of the perforation of the nasal septum with the graft between the septum membranes. There was no statistically significant difference concerning acute inflammation, vascular congestion and fibrosis between the 2 groups. In cases in which the graft remained in place, there was no change in its integrity. It may be used as a substructure for reepithelization of the perforation edges.

Estudo experimental da resposta tecidual à presença de celulose produzida por Acetobacter xylinum no dorso nasal de coelhos / Experimental study of the tissue reaction caused by the presence of cellulose produced by Acetobacter Xylinum in the nasal dorsum of rabbits

Vários materiais são propostos para reconstrução nasal, não havendo consenso sobre qual o melhor. A manta de celulose produzida por bactéria pode ser mais um elemento para adição cartilaginosa. Não há estudos deste material no dorso nasal. OBJETIVO: Avaliar a resposta tecidual à presença da celulose bacteriana no dorso nasal de coelhos. MATERIAL E MÉTODO: Foram utilizados 22 coelhos Nova Zelândia, sendo que em 20 deles foi implantada a manta de celulose no dorso nasal e em 2 controles nada foi feito. Foram acompanhados por um período de três e seis meses, sendo então retirados as regiões do dorso nasal e narinas dos coelhos e realizado estudo histopatológico levando em consideração parâmetros definidos de condição inflamatória como congestão vascular, intensidade do processo inflamatório e presença de exsudato purulento. RESULTADOS: O processo inflamatório manteve-se estável, demonstrando sua relação com o procedimento cirúrgico, e não com a presença da manta de celulose. Nos demais parâmetros estudados não houve diferença estatisticamente significante. CONCLUSÃO: A manta de celulose de Acetobacter xylinum mostrou boa biocompatibilidade e manteve-se estável no decorrer do tempo de estudo, podendo ser considerada um bom material para uso na elevação do dorso nasal.

Several materials have been proposed for nasal reconstruction. There is no consensus on which is the best. The cellulose blanket produced by bacteria may be a possible cartilaginous addition element to the nose. AIM: to study tissue reaction to cellulose in the dorsal nose of rabbits. MATERIALS AND METHODS: 22 New Zealand rabbits were used. In 20 a cellulose blanket was implanted in the nasal dorsum and 2 served as controls. They were followed up through a period of three and six months, after which their nostrils and nasal dorsums were removed and histological studies were carried out on them, considering defined parameters of inflammation such as vascular congestion, intensity of the inflammatory process and presence of purulent exudate. RESULTS: The inflammatory process remained stable, showing its relationship with the surgical procedure and not with the presence of the cellulose blanket. There were no statistical differences in the other parameters. CONCLUSION: The cellulose blanket produced by Acetobacter xylinum presented good biocompatibility, remained stable during the entire study period, and could be considered a good material for elevating the nasal dorsum.

Controllable bio-fabrication based on microbes / 生物工程学报

Microorganisms in nature have rich variety, whose sizes are from nano scale to micro scale. Therefore, microbes can be used as natural "building blocks" in nano/micro multi-level fabrication processes. At present, most of the bio-manufacturing methods do not apply to direct control of living microbes. Their microbiological global functions and superiorities are not available. In this paper, two novel nano/micro bio-fabrication approaches, micro-fluidic control method and magnetic control method have been established. The living microbes could be manipulated to form micro-scaled patterns or to move orientedly. By these approaches, living microbes are taken as nano/micro robots. We could employ their specific biological functions and regulate their controllable self-assembly, which is expected to design and create a series of new special functional materials and devices.

Comparison of locally-produced microcellulose dressing from Acetobacter xylinum with silver sulfadiazine cream in the treatment of acute superficial partial thickness burn wounds: A preliminary report

OBJECTIVES: To compare the efficacy, safety and cost of locally-produced microcellulose dressing from Acetobacter xylinum in promoting healing of superficial partial thickness burn wounds to standard dressing using silver sulfadiazine (SSD) cream and gauze in terms of the following: time to healing, morbidity/infection rate, pain score, scarring and cost of dressingMETHODS: Comparative controlled trial. Each patient served as his own control, that is, one area was randomized to the treatment group dressed with microcellulose dressing, while another was assigned to the control group dressing with SSD. Both areas were inspected regularly for signs of infection, as well as reepithelialization. The patients were also asked for the pain score at rest, and during dressing using the visual analog scale. Once healed, the Vancouver scale was used to grade the resultant scars.RESULTS: Ten patients were included from February to June 2008. All patients were males, with a mean age of 30.1 years (17-48 years, ± 12.05), and a mean total body surface involvement of 12.75% (4-22% TBSA,?± 7.0) superficial partial thickness burns. The time in days to complete reepithelialization was significantly lower in MCD dressings (p-value=0.05760). The mean times (in days) to complete reepithelialization for MCD and SSD were 11.4 (90 percent CI: 9.80-13.0) and 13.8 (90 percent CI: 12.33-15.27) days, respectively. Statistical analysis of differences of VAS scores during dressing changes were significantly lower in MCD dressing on days 2,6,9 and 12 post burn. Background VAS scores were also lower in those patients with MCD dressing on days 6, 9 and 12 post burn. None of the wounds in either treatment arm had signs of infection. Scarring of wounds dressed with MCD were better, based on the Vancouver scar score than those dressed with SSD (p = 0.0299). The means for the Vancouver score for MCD and SSD were 2.65 (90 percent CI: 2.25-3.05) and 4.05 (90 percent CI: 3.32-4.78), respectively.CONCLUSION: Microcellulose dressing is significantly more effective than silver sulfadiazine in treatment of second degree burn wounds in terms of number of days to full reepithelialization and quality of scarring. Dressing with MCD was less painful on days 2, 6, 9 and 12 post burn. Background VAS scores were also lower on days 6, 9 and 12 post burn. None ofthe wounds in both treatment arms had signs of infection throughout the treatment period.

Avaliação da resposta inflamatória traqueal ao curativo de celulose bacteriana após escarificação cirúrgica em coelhos / Tracheal inflammatory response to bacterial cellulose dressing after surgical scarification in rabbits

Dentre as causas de insucesso nas cirurgias para a estenose traqueal está a formação de tecidos de cicatrização exuberantes. O uso de curativos para evitar esta reação pode ser de grande valia nestes casos. A celulose bacteriana produzida por acetobacter xylinun pode ser útil nestes casos. Não há estudos na região laringotraqueal. OBJETIVO: Avaliar a resposta tecidual subglótica de coelhos após escarificação e colocação de curativo de celulose, comparando com grupo controle. FORMA DE ESTUDO: Experimental MATERIAL E MÉTODOS: Foram estudados 26 coelhos, submetidos a escarificação da região laringotraqueal e tratados com curativo e comparados com controle. Foram estabelecidos 4 tempos de seguimento. Os seguimentos laringotraqueais foram examinados histologicamente e os resultados foram avaliados estaticamente. RESULTADOS: O grupo de estudo evoluiu com o passar do tempo com resultados estatisticamente semelhantes ao do grupo controle, nos parâmetros Congestão vascular, Exsudato purulento, Inflamação aguda, Integridade do epitélio, Proliferação fibrosa e Reação granulomatosa. CONCLUSÃO: Não foram observadas diferenças entre os grupos controle e de estudo quanto aos parâmetros inflamatórios ou cicatriciais. Não houve sinais inflamatórios relacionados ao uso da membrana de celulose que não tivessem ocorrido devido ao traumatismo cirúrgico.

Exuberant scarring tissue formation is among the failure causes of tracheal stenosis surgery. Dressings that could avoid such reaction could be very helpful in these cases. Bacterial cellulose, produced by acetobacter xylinun can be useful in these cases. There are no studies in the laryngotracheal region. AIM: to assess subglottic tissue response in rabbits after scarification and placement of cellulose dressing, and comparing it to a control group. STUDY DESIGN: experimental. MATERIALS AND METHODS: 26 rabbits underwent laryngotracheal scarification, received the dressing and were compared to the control group. We established four follow up periods. Laryngotracheal specimens underwent histological exam and the results were statistically assessed. RESULTS: the study group had statistically similar results when compared to the control group in the following parameters: vascular congestion, purulent oozing, acute inflammation, epithelial integrity, fibrous proliferation and granulous proliferation. CONCLUSION: we did not observe differences between the study and control groups as far as inflammation and scarring are concerned. There were no inflammatory signs associated with the use of the cellulose membrane that did no occur because of surgery.