An alternative to nerve repair using an antioxidant compound: a histological study in rats.

The fascicular composition and organisation of the inferior alveolar nerve (IAN) were determined to confirm the microarchitecture of the IAN bundles into each of the mandibular teeth, including the composition of the mental nerve. The aim of this study was to evaluate peripheral nerve repair after the application of an antioxidant compound to the damaged nerve tissue to elevate the concentration and bioavailability of elements capable of favouring tissue repair. Twenty-five Wistar rats were divided into groups: The Control 1 (Ctl 1) (n = 5) animals had the ischiatic nerve exposed with no suture injury and were sacrificed at 30 days post-operatively. The Control 2 (Ctl 2) (n = 10) animals had the ischiatic nerve exposed, and the nerve was injured using suture in three distinct regions. In the experimental (Exp) animals (n = 10), an antioxidant organic compound was applied to the nerve injury site. The animals with nerve injury (Ctl2 and Exp group) were sacrificed at 15 and 30 days post-operatively. The histological analysis showed less degeneration in the Exp group at 15 and 30 days post-operatively. Nerve neoformation forming a connection between the distal and proximal suture sites was observed in the experimental group. This study presented an alternative to nerve repair using an antioxidant compound.

Cytotoxicity of cannulas for ophthalmic surgery after cleaning and sterilization: evaluation of the use of enzymatic detergent to remove residual ophthalmic viscosurgical device material.

PURPOSE: To evaluate the cytotoxicity of reusable cannulas for ophthalmic surgery after the cannulas were filled with an ophthalmic viscosurgical device (OVD) and cleaned with an enzymatic detergent. SETTING: Microbiological Testing Laboratory, Department of Medical-Surgical Nursing, University of São Paulo School of Nursing, and Cell Culture Section, Adolfo Lutz Institute, São Paulo, Brazil. DESIGN: Experimental study. METHODS: The sample consisted of 30 reusable 25-gauge injection cannulas, 20.0 mm in length, whose lumens were filled with an OVD solution for 50 minutes. The following steps were used to process the cannulas: (1) presoaking, (2) washing the lumen using a high-pressure water jet, (3) backwashing with enzymatic detergent in ultrasonic cleaner, (4) preliminary rinsing with tap water, (5) final rinsing with sterile distilled water, (6) drying with compressed filtered air, (7) wrapping in surgical-grade paper, and (8) steam sterilization at 134°C for 4 minutes. The cannulas were then tested for cytotoxicity according to the United States Pharmacopeia 32. RESULTS: The cleaning protocol used in this study removed residues of OVD solution and enzymatic detergent as shown by the lack of cytotoxicity of all sample extracts. CONCLUSION: This cleaning protocol has the potential to minimize the occurrence of toxic anterior segment syndrome associated with residues of OVD solutions and enzymatic detergents. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Estudo comparativo entre os métodos in vivo e in vitro na análise toxicológica de produtos de higiene descartáveis e sua avaliação microbiológica / Comparative study between in vivo and in vitro toxicological methods and microbiological quality assessment in disposable hygienic products

Os objetivos deste trabalho foram comparar os métodos in vivo e in vitro na avaliação da toxicidade dérmica e estimar a qualidade microbiológica de 60 amostras de produtos de higiene descartáveis comercializados na cidade de São Paulo. Nos testes de toxicidade in vivo foram utilizados o “Método deDraize” e o “Método Modificado por Magnusson e Kligman” e nos testes in vitro o Método de “difusão em agar”, empregando as linhagens celulares, NCTC clone 929 (ATCC- CCL1) e SIRC (ATCC-CCL-60). A análise microbiológica foi realizada de acordo com o “Bacteriological Analytical Manual OnLine”, 2001. Os produtos analisados não apresentaram irritação dérmica primária, cumulativa e sensibilização cutânea, mas nos testes in vitro, foi observada em 18 amostras toxicidade leve à severa, com índice de zona (IZ) variando de 2,0 - 4,0 nas duas linhagens celulares testadas. A análise microbiológica apresentou número elevado de bactérias aeróbias mesófilas, resultados positivos para bolores, presença de Enterobacter sp, Enterobacter agglomerans e Enterobacter cloacae. De acordo com os resultados obtidos e para garantir a segurança da saúde do usuário recomenda-se que, além dos testes já mencionados pela legislação vigente, seja também preconizado teste de citotoxicidade in vitro, para os produtos de uso interno e externo. A realização prévia deste teste pode se constituir em mecanismo de triagem.

Isolation of the wild-type rubella virus in rabbit kidney cell line RC-IAL

O presente estudo descreve o isolamento e o crescimento do vírus selvagem da rubéola na linhagem celular RC-IAL. A susceptibilidade da linhagem celular RC-IAL (rim de coelho, Instituto Adolfo Lutz) para o vírus-padrão da rubéola RA 27/3 foi anteriormente descrito por nós(4). Amostras de 20 pacientes com suspeita de infecção por rubéola foram testadas por sorologia, isolamento viral e nested PCR. Os soros foram testados por Elisa para detecção de anticorpos reagentes para rubéola e nested PCR para detectar o RNA viral. As amostras clínicas de sangue, urina, fragmento de placenta e líquido amniótico foram inoculadas nas linhagens celulares RC-IAL (rim de coelho, Instituto Adolfo Lutz) e Sirc (córnea de coelho). O vírus da rubéola foi isolado das amostras clínicas de quatorze pacientes. O efeito citopático (ECP) foi examinado por microscopia de contraste de fase, e o RNA do vírus da rubéola foi amplificado por nested PCR. Os resultados obtidos mostram que a linhagem celular RC-IAL é um excelente substrato para isolamento do vírus da rubéola. Estes dados são importantes, pois poucas linhagens descritas na literatura apresentam efeito citopático que possibilite seu uso para isolar o vírus da rubéola de material clínico.

Biocompatibility study of polymeric biomaterials.

Polymeric hydrogels are used as wound dressing material since these materials show advantages such as pain relief, exudates absorption, barrier to microorganisms, permeability, and others. This article shows the results obtained in a study aiming to know the biological performance of different polymeric materials to be used in contact with skin: PVP hydrogels and acrylate adhesive. The biocompatibility was determined by in vitro assay of cytotoxicity and in vivo assay by using the contact test of irritability in rabbits. All the tested samples presented no toxicity and no dermal irritation.

A proposal of an alternative in vitro method for the evaluatiopn of the safety of shampoos

Although tests using animals are still demanded in the evaluation fo shampoos, there is a strong evidence of a tendency for replacing them by in vitro systems. This study aims at defining conditions for the application of a method using NCTC clone 929 cells, as an alternative. Procedures employed to test non diluted samples of shampoos for adults resulted in irritation (in the in vivo method); the same result was not observed when samplesdiluted to a 25 per cent concentration were tested. In the in vitro tests, the same shampoos presented a perfect correlation of results when not diluted (cytotoxic) and when diluted to a 0.1 per cent concentration (non cytotoxic). When the shampoos for children use were tested, the only case of irritation happened with one of the 4 non-diluted shampoos. The absence of cytotoxicity was observed in the in vitro test, after diluting all the samples to 1 per cent and 0.1 per cent. It is possible thus to use the in vitro test instead of the vivo one, if preceded by a careful validation with emphasis on the concentration of the product

RC-IAL cell line: sensitivy of rubella virus grow

Objetivo: Descreve-se o crescimento do vírus-padräo da rubéola RA-27/3 na linhagem celular RC-IAL, com desenvolvimento de efeito citopático em resposta à infecçäo viral. Para este propósito, o vírus-padräo foi titulado simultaneamente nas linhagens celulares Vero, SIRC e RK13. Métodos: O vírus-padräo da rubéola RA-27/3 foi inoculado na linhagem celular RC-IAL (rim de coelho, Instituto Adolfo Lutz). Placas contendo 1,5c105 células/ml foram inoculadas com 0,1ml do contendo 1x104 DICT50/0,1 ml. O efeito citopático correspondente a 25 por cento foi observado após 48h e 100 por cento após 96h. Os resultados obtidos foram comparados com o crescimento do vírus nas linhagens celulares SIRC, Vero e RK13. O vírus da rubéola na linhagem celular RC-IAL foi detectado por imuno-histoquímica. Resultados: As células inoculadas com o vírus da rubéola apresentaram efeito citopático nas primeiras 48h. As células apresentaram aspecto arredondado, com formaçäo de alguns prolongamentos citoplasmáticos e sincícios, produzindo células multinucleadas. A curva do crescimento da infectividade do vírus foi praticamente a mesma que a observada nas outras linhagens celulares. Conclusäo: Os resultados obtidos mostram que a linhagem celular RC-IAL é um ótimo substrato para crescimento do vírus da rubéola, pois poucas linhagens celulares descritas na literatura apresentam efeito citopático considerável e podem ser utilizadas para preparaçäo de antígenos e nos testes de diagnóstico sorológico para o vírus da rubéola

Citotoxicidade in vitro das membranas de hidrogel reticuladas por radiação ionizante / In vitro cytotoxicity of hydrogel membranes reticulate by ionizing radiations

Hidrogéis constituídos de poli N-vinil-2-porrolidona (PVP), ágar e polietilenoglicol (PEG) säo utilizados como membranas para uso tópico, no tratamento de lesöes de pele. Com o objetivo de melhorar algumas das propriedades mecânicas da membrana, como tensäo de ruptura e elongaçäo, substituiu-se o PEG pelo copolímero poli (dimetilsiloxano)-co-poli (óxido de etileno) (SEO). A biocompatibilidade "in vitro" das membranas de PVP-SEO com diferentes concetraçöes de SEO foi testada em cultura de células. O teste de citotoxicidade foi realizado pelo estudo comparativo de dois métodos: 1) difusäo em ágar, utilizando-se as linhagens celulares RC-IAL e NCTC Clone L-929 e 2) inibiçäo da formaçäo de colônias utilizando-se a linhagem celular CHO-K1. Os resultados obtidos nos dois métodos foram análogos e demonstraram que as membranas do PVP-SEO apresentaram toxicidade nas concentraçöes testadas e nas linhagens celulares utilizadas. Foi possível também concluir que a adiçäo de SEO ocasiona caráter citotóxico às membranas de PVP

Hydrogels composed by PVP, agar and PEG are used as wound dressings in the treatmentof skin ulcers. In order to improve the mechanical properties of the membrane, such as tensile strengthand elongation, PEG was replaced by copolymer poly (dimethilsiloxane)-co-polyoxiethylene (SEO).The "in vitro" biocompatibility evaluation of PVP-SEO membranes with different concentrations of SEOwas carried out in cell culture. A comparative study of cytotoxicity assays was performed by twomethods: 1) diffusion agar assay, using RC-IAL and NCTC Clone L-929 cells and 2) colony suppressionassay, using CHO-K1 cells. In the cytotoxic evaluation of PVP-SEO membranes by both methods,analogous results were obtained. It was also possible to conclude that the addition of SEO promotescytotoxicity in PVP membranes

Detecção da citotoxicidade de materiais biocompatíveis nas linhagens celulares MRC-5, HeLa e RC-IAL / Detection of cytotoxicity of biocompatible materials in MRC-5, HeLa, and RC-IAL cell lines

The sensitivity of diploid and heteroploid cell lines for detection of cytotoxicity using the agar diffusion method on cell culture, was tested with ascorbic acid solution of different concentrations. A total of 562 samples of 21 various materials were tested. The heteroploid cell line, RC-IAL, showed in relation to the MRC-5 and HeLa cell lines, greater sensitivity because it showed the presence of cytotoxic effect with the lowest concentration used (10 and 25 micrograms/ml) of ascorbic acid and showed greater diameter of cytotoxic halo in 15 samples and equal diameter in 16 of the 43 positive samples (7.6). Out of 43 positive samples, the MRC-5 line did not show cytotoxicity in 3 sponge samples and 1 of acrylic resin. The PVC (polyvinylchloride) and polyethylene rarely showed positivity, while, the plastic, cotton and acrylic resin demonstrated cytotoxicity in about 5 of samples. We thus suggest the use of the RC-IAL and HeLa cell lines for continuation of this type of analysis at Adolfo Lutz Institute.