Este trabalho está baseado no desenvolvimento do compósito poli(metacrilato de metila) (PMMA) microfibra de biovidro 45S5® (BV) com porosidade para aplicação direcionada a implantes ósseos. O PMMA é um material do tipo bioinerte amplamente utilizado na fabricação de implantes. O biovidro 45S5® é um biomaterial bioativo classe-A, que significa ser capaz de integração com tecidos moles e ósseos. O presente trabalho objetiva a conjugação das propriedades destes dois materiais em um conceito que introduz microfibra de biovidro 45S5® e porosidade em uma matriz de PMMA na busca de um material com elevada osteointegração e que permita a manufatura de implantes com adequada resistência a carregamentos mecânicos. Foram manufaturados e avaliados fisicamente e in vivo corpos de prova de PMMA com introdução de 20% de microfibra de biovidro (densos e porosos a 80%), corpos de PMMA com introdução de hidroxiapatita (densos e porosos a 80%) e de PMMA (densos e porosos a 80%) para controle. Foram realizados testes mecânicos de compressão e de flexão a três pontos para medidas de resistência e rigidez. Também foram realizadas medidas da microdureza Vickers e da densidade das amostras. Os resultados médios obtidos da tensão de escoamento e módulo elástico para os corpos de prova com introdução de 20% de microfibra de biovidro nos ensaios de compressão foram de 44 MPa e 1403 MPa respectivamente para as amostras densas e de 8 MPa e 13 MPa para as amostras porosas e nos ensaios de flexão foram de 48 MPa e 8129 MPa para os corpos densos e de 5 MPa e 97 MPa para os corpos porosos. A modelagem matemática a partir dos resultados permite a determinação antecipada da formulação para o atendimento específico de cada proposta de implante. Os implantes ensaiados in vivo com adição de microfibra de Biovidro 45S5® foram os que apresentaram os melhores resultados em integração óssea e controle da inflamação local. / This work is based on the development of poly(methyl methacrylate) (PMMA) - bioglass 45S5® microfibers composite with porosity for bone implants application. PMMA is a bioinert material widely used in the manufacture of biological implants. The 45S5® bioglass is a bioactive class-A biomaterial which indicates ability to integrate with bone and soft tissues. The present study aims to combine the properties of these two materials on a concept that introduces bioglass 45S5® microfibers and porosity in a matrix of PMMA in order to find a material with high bone integration and capable of manufacture implants with adequate resistance to mechanical loads. Samples of PMMA with the introduction of 20% of bioglass microfiber (dense and 80% of porous), PMMA with introduction of hydroxyapatite (dense and 80% of porous), and PMMA (dense and 80% of porous) for control were fabricated and evaluated both physically and in vivo. Mechanical tests such as compression and three points bending have been performed for measurements of strain and stiffness. Measurements of Vickers microhardness and density of the samples also were performed. The average results of yield stress and elastic modulus for the samples with the introduction of 20% microfiber bioglass in compression tests were 44 MPa and 1403 MPa respectively for dense samples and 8 MPa and 13 MPa for porous samples and in bending tests were 48 MPa and 8129 MPa for dense bodies and 5 MPa and 97 MPa for the porous bodies. The mathematical modeling based on the results allows the early determination of the formulation to meet the specific needs of each implant proposal. The implants tested in vivo with addition of 45S5® bioglass microfiber presented the best results in bone integration and control of local inflammation when compared with all the other groups with the scaffold presence.

Resumo: A proposta deste estudo foi avaliar a associação do PLA/PGA ao redor de implantes osseointegráveis instalados sem estabilidade primária, por meio da análise biomecânica, histométrica e da expressão das proteínas OPG, RANKL, OC e COL-I. Vinte e cinco coelhos receberam 2 implantes de 2,6/ 6,0mm na tíbia direita em leitos receptores preparados com 3,0mm. Um defeito foi preenchido com coágulo sanguíneo e o outro com o PLA/PGA previamente à instalação dos implantes. A eutanásia dos animais foi realizada nos períodos de 5, 15, 40 e 60 dias pósoperatórios e o teste biomecânico foi realizado nos períodos de 40 e 60 dias. As peças foram submetidas ao processamento imunoistoquímico e coradas por HE. As peças de 5 animais do período de 60 dias foram desgastadas e coradas com vermelho de alizarina e azul de Stevenel. Não houve diferenças nos valores de torque-reverso na comparação entre os grupos e os períodos avaliados. A análise das imunomarcações não evidenciou diferença estatística entre os grupos para cada período. Houve evidência estatística de maior expressão de RANKL no período de 15 dias no grupo tratado em relação à expressão de colágeno I. A proteína RANKL apresentou mais percentuais de marcações celulares acima de 50% quando comparada às outras proteínas. Não houve diferença estatística entre os grupos quanto à extensão linear de contato entre tecido ósseo e implante. Conclui-se que o copolímero apresentou biocompatibilidade e permitiu neoformação óssea em contato com o implante. Além disso, ocorreu o processo de osseointegração em ambos os grupos, mesmo na ausência de estabilidade primária dos implantes. / Abstract: The purpose of this study was to evaluate the association of the PLA/PGA around of osseointegrated implants installed without primary stability, through the biomechanics, histometric analysis and of the OPG, RANKL, OC and COL-I proteins expression. Twenty-five rabbits received 2 implants of 2.6 / 6.0mm in the right tibia in receptor beds prepared with 3,0mm. A defect was fulfiled with blood clot and the other with the PLA/PGA, previously to the implants installation. The euthanasia of 25 animals was performed at 5, 15, 40 and 60 days and the biomechanical test was performed at 40 and 60 days. The samples followed immunoistochemistry processing and were stained with HE. The pieces of 5 animals of 60 days were trimmed and stained with alizarin red and Stevenel's blue. There were not differences in the torque-reverse between the groups and periods. The analysis of the immunolabelings did not evidence statistic difference between the groups for each period. There was statistics evidence of increase in the RANKL expression in the 15 days period, in the treated group, when compared to the COL-I. The RANKL protein presented more percentiles of immunolabelings above 50% when compared to the other proteins. There was no statistics difference between the groups regarding contact linear extension between bone tissue and implant. It can be concluded that the copolymer presented biocompatibility and it allowed bone neoformation in contact with the implant. Besides, the osseointegration process happened in both groups, even in the absence of primary stability of the implants. / Orientador: Eduardo Hochuli Vieira / Coorientador: Roberta Okamoto / Banca: Idelmo Rangel Garcia Júnior / Banca: Cássio Edvard Sverzut / Mestre

Made available in DSpace on 2017-07-24T19:22:23Z (GMT). No. of bitstreams: 1 AriadneCristiane.pdf: 1142679 bytes, checksum: b75266aff500589fbbff70e1db04f74b (MD5) Previous issue date: 2004-06-17 / The purpose of this study was to evaluate physic-chemical characteristics and the biocompatibility of the bioglass, developed by the UEPG Chemistry Department, (UEPG Bioglass) and compare it with the PerioGlas® e Biogran®. The physicchemical characterization was made by scanning electron microscopy (SEM) (size and morphology of particles); scanning electron microscopy/energy dispersive X Ray (MEV/EDAX) (chemical elements); X Ray diffractometry (DRX) (structure); X Ray fluorescence (FRX) (chemical elements) For the biocompatibility test was used 100 rats: Gl-PerioGlas® - 25 animals; Gll – Biogran® - 25 animals; Glll – Biovidro UEPG – 25 animals; GIV – Control (surgical procedure without implantation of biomaterial) – 25 animals. The animals were evaluated at 7, 15, 21, 45 and 60 days. It was used histomorphometric analysis to determine the size of inflammatory reaction, size of granules, the presence and quantity of polymorphonuclear cells (PMN), mononuclear (MN) and fibroblast (F). The results shown that the particles of the three materials were irregular with superficial roughness. The medial size of PerioGlas® granules was 222,00±40,64 µm. The Biogran® granules with 385.09±68.51µm. And the UEPG Bioglass was 102.86±36.22µm. There was significant difference in the size of granules (p<0.001-ANOVA). The three samples presented calcium, oxygen, sodium, phosphorus and silica, aggregated on silica oxide, sodium oxide, calcium oxide and phosphorus oxide. The materials were no crystalline and with crystalline points in their surfaces. There was significant difference on size of inflammatory reaction between groups, times and interaction (group*time) (p<0.001). There was not significant difference between on the count of MN between groups (p=0.117), there was difference between times (p<0.001) and interaction (p=0.022). There was significant difference (p<0.001) on the count of PMN between the times, groups and interaction. There was not significant difference on the count of F between the groups (p=0.131) and interaction (p=0.665), with significant difference between the times (p=0.008). There was significant difference on granules size between the groups, time and interaction (p<0.001). It was concluded that the three materials were biocompatible and bioreabsorbable, without sign of osteoinducture capacity. / O presente trabalho se propôs a avaliar as características físico-químicas e a biocompatibilidade do biovidro desenvolvido pelo departamento de Química da UEPG (Biovidro UEPG) e compará-lo com o PerioGlas® e Biogran®. Realizou-se a caracterização físico-química através da microscopia eletrônica de varredura (MEV) (tamanho e morfologia das partículas); microscopia eletrônica de varredura/ energia dispersiva de Raios X (MEV/EDX) (elementos químicos); difratometria de Raios X (DFR) (estrutura); fluorescência de Raios X FRX (elementos químicos). Para o teste de biocompatibilidade utilizou-se 100 ratos, sendo: GI- PerioGlas® - 25 animais; GIIBiogran ® - 25 animais; GIII- Biovidro UEPG - 25 animais; GIV- Controle (procedimento cirúrgico sem implantação do biomaterial) - 25 animais. Avaliou-se os animais em 7, 15, 21, 45 e 60 dias. Através de histomorfometria determinou-se o tamanho da reação inflamatória, tamanho dos grânulos, presença e quantidade de células polimorfonuclear (PMN), mononuclear (MN) e fibroblasto (F). Os resultados mostraram que as partículas dos três materiais apresentaram-se não uniformes e com rugosidade superficial. Os grânulos de PerioGlas® apresentaram-se com tamanho médio de 222,00±40,64µm. O Biogran® com 385,09±68,51µm. E o Biovidro-UEPG com 102,86±36,22µm. Houve diferença significativa no tamanho dos grânulos (p<0,001- ANOVA). Identificou-se nas três amostras cálcio, oxigênio, sódio, fósforo e sílica, agrupados em óxido de sílica, óxido de sódio, óxido de cálcio e óxido de fósforo. Os materiais mostraram-se não cristalinos e com pontos de cristalização. Houve diferença significativa no tamanho da reação inflamatória entre os grupos, tempos e interação (grupo*tempo) (p<0,001). Na contagem de MN não houve diferença significativa entre os grupos (p=0,117), havendo entre os tempos (p<0,001) e interação (p=0,022). Houve diferença significativa (p<0,001) na contagem de PMN entre os tempos, grupos e interação. A contagem de F não mostrou diferença significativa entre os grupos (p=0,131) e interação (p=0,665), havendo diferença entre os tempos (p=0,008). Houve diferença significativa no tamanho dos grânulos entre os grupos, tempo e interação (p<0,001). Concluiu-se que os três materiais apresentaram-se biocompatíveis e bioreabsorvíveis, sem indício de capacidade osteoindutora.

This paper studies the current cotton market situation. The situation is a recent vast increase in cotton fibre price, mainly due to tight supply and demand circumstances. Focus is on two issues; how the fibre price affect companies cost wise and the likely future development of the cotton market. The cotton market has been studied by hard facts and contemporary views from industry people and companies. Factors influencing the cotton market such as economical growth, population and substitute textile fibres are taken into consideration. Besides how companies themselves claim to respond to the cotton price increase cost calculations approximated by thumb rules of the industry are performed. The result is a higher cost, derived from higher cotton price, at the finish garment stage. The magnitude depend on if one sees it relative to retail price or manufacturing cost along with how the participant in the value chain react. The future cotton market is evaluated by what might effect cotton supply and cotton demand and how the market mechanism is likely to answer. Short term the high prices seem to lower the demand and along with a larger harvest next season prices should be lowered. Long term the price is suggested to remain high because of a larger grow in demand then supply. / Program: Magisterutbildning i Applied Textile Management

This paper studies the current cotton market situation. The situation is a recent vast increase in cotton fibre price, mainly due to tight supply and demand circumstances. Focus is on two issues; how the fibre price affect companies cost wise and the likely future development of the cotton market. The cotton market has been studied by hard facts and contemporary views from industry people and companies. Factors influencing the cotton market such as economical growth, population and substitute textile fibres are taken into consideration. Besides how companies themselves claim to respond to the cotton price increase cost calculations approximated by thumb rules of the industry are performed. The result is a higher cost, derived from higher cotton price, at the finish garment stage. The magnitude depend on if one sees it relative to retail price or manufacturing cost along with how the participant in the value chain react. The future cotton market is evaluated by what might effect cotton supply and cotton demand and how the market mechanism is likely to answer. Short term the high prices seem to lower the demand and along with a larger harvest next season prices should be lowered. Long term the price is suggested to remain high because of a larger grow in demand then supply. / Program: Applied Textile Management

O uso crônico de etanol prejudica diretamente o processo biológico de reparo ósseo, principalmente pela inibição das células osteoblásticas, podendo causar retardo de consolidação ou pseudoartrose. Vários biomateriais naturais ou sintéticos, têm sido utilizados como uma alternativa aos enxertos ósseos. Os biomateriais sintéticos, como o Beta Fosfato Tricálcico (-TCP) são biocompatíveis, biodegradáveis e osteocondutíveis, por orientar as células osteoblásticas, promovendo a neoformação óssea. Sendo assim, objetivou-se avaliar a influência da ingestão crônica de etanol no processo de reparo ósseo de defeitos cranianos tratados com -TCP® comparativamente aos preenchidos com coágulo sanguíneo e a sua interferência sobre a massa corporal. Foram utilizados 40 ratos machos (Rattus norvegicus), distribuídos aleatoriamente em 2 grupos: GAG - receberam água como dieta liquida, e GAL - receberam etanol a 25%. O GAL foi submetido inicialmente à adaptação gradativa ao álcool e depois permaneceu a 25% por 90 dias. Após o término desse período, todos os animais foram submetidos à cirurgia experimental. Nos ossos parietais de cada animal, foram confeccionadas duas cavidades 5,0 mm de diâmetro ao lado da sutura sagital, de forma que o parietal direito foi preenchido com -TCP® e o esquerdo com coágulo. Dessa forma, os grupos GAG e GAL foram divididos de acordo com o preenchimento dos defeitos: GC-AG (Grupo Coágulo Água), GC-AL (Grupo Coágulo Álcool), GB-AG (Grupo Biomaterial Água) e GB-AL (Grupo Biomaterial Álcool). O reparo ósseo foi observado de acordo com o período de eutanásia: 10, 20, 40 e 60 dias após a cirurgia. Após inclusão histológica, as peças foram submetidas à análises histomorfológica e histomorfométrica. Na análise da variação da massa corporal, observou-se que as massas iniciais do GAG foram maiores que GAL e as massas finais de GAG aumentou significativamente apenas em 60 dias e no GAL em todos os períodos. Na análise histomorfológica, observou-se nos períodos iniciais de todos os grupos a presença de tecido conjuntivo fibroso preenchendo toda área central do defeito. Os grupos com os defeitos preenchidos com -TCP apresentaram tecido reacional com as partículas envoltas por células inflamatórias. No período final de análise, observou-se em todos os grupos pequena neoformação óssea com a área central preenchida por tecido conjuntivo fibroso. Nos grupos GC-AL, GB-AG e GB-AL evidência de reação inflamatória menos intensa. Na análise histomorfométrica em relação à influência do tempo na neoformação óssea, os grupos GC-AG e GC-AL apresentaram o mesmo perfil gráfico em todos os períodos exceto 60 dias. O grupo GB-AG houve aumento substancial de neoformação em todo experimento e GB-AL pequeno aumento, mas não foi significante. Em relação à interferência da dieta, observou-se maior percentual de formação óssea nos grupos que consumiram água nos períodos 40 e 60 dias. E em relação ao tipo de preenchimento, observou-se no grupo GC-AG maior formação nos períodos de 20 e 40 dias. Já nos GB-AG e GB-AL a formação foi similar durante todo experimento. Conclui-se que o -TCP® não foi capaz de contribuir para melhor regeneração óssea, apresentando desempenho inferior nos animais que consumiram álcool. / Chronic use of ethanol directly affects the biological process of bone repair, primarily by inhibition of osteoblastic cells. This may cause delayed consolidation or nonunion. Various natural and synthetic biomaterials have been used as alternatives to bone grafting. Synthetic biomaterials such as beta tricalcium phosphate (-TCP) are biocompatible, biodegradable, and osteoconductive, guiding osteoblastic cells and promoting bone formation. Thus, the objective was to evaluate the influence of chronic ethanol intake on the bone healing process of cranial defects treated with - TCP® compared to those filled with blood clot. Forty male rats were used (Rattus norvegicus), randomly divided into two groups: GAG received water as a liquid diet, and GAL received 25% ethanol. The GAL group was initially subjected to gradual adaptation to the alcohol and then maintained at 25% for 90 days. At the end of this period, all animals were submitted to experimental surgery. In the parietal bone of each animal, two cavities were prepared, 5.0 mm in diameter on the side of the sagittal suture, and the right parietal was filled with -TCP® and left to clot. Thus, the GAG and GAL groups were divided according to the filling of defects: GC-AG (Clot Water Group); GC-AL (Clot Alcohol Group); GB-AG (Biomaterial Water Group); and GB-AL (biomaterial Alcohol Group). The bone repair was observed according to the euthanasia period: 10; 20; 40; and 60 days after surgery. After a histological inclusion, the pieces were submitted to histomorphological and histomorphometric analysis. The histomorphological analysis was observed in the initial periods of all groups fibrous connective tissue filling the entire central area of the defect. The groups of defects filled with -TCP showed tissue reaction to particles surrounded by inflammatory cells. At the end of the period of analysis, it was observed that in all groups there was little bone formation, with the central area filled with fibrous connective tissue. In the GC-AL, GB-AG, and GB-AL groups there was evidence of less intense inflammatory reaction. In histomorphometric analysis regarding the influence of time in osteogenesis, the GC-AG and GC-AL groups had the same graphic profile in all periods except 60 days. In the GB-AG group there was a substantial increase of formation in every experiment, and in the GB-AL a small increase, but it was not significant. Regarding the influence of diet, there was a higher percentage of bone formation in the group that consumed water in the 40- and 60-day periods, and in the type of filling, increased formation in the periods of 20 and 40 days was observed in the GC-AG group. In the GB-AG and GB-AL groups, the formation was similar throughout the experiment. It is concluded that the -TCP® was not able to contribute to better bone regeneration, with underperformance in animals that consumed alcohol.

A evolução do processo de reparo ósseo foi avaliada, em alvéolos dentários de ratos, frente ao coágulo sangüíneo, bem como ao implante de sulfato de cálcio di-hidratado e da hidroxiapatita BTCP GenPhos. Foram utilizados 48 ratos machos, divididos em três grupos, nos quais foi realizada a extração do incisivo superior direito. No grupo I, os alvéolos foram preenchidos com coágulo sangüíneo, permanecendo dessa forma como controle. No grupo II, implantou-se no alvéolo sulfato de cálcio di-hidratado e, no grupo III, realizou-se a inserção da hidroxiapatita BTCP GenPhos nos alvéolos. Após 7, 15 e 30 dias dos procedimentos cirúrgicos, os animais foram mortos, as hemimaxilas direitas removidas e processadas histologicamente para a realização das análises microscópicas descritiva e quantitativa, cujos resultados foram submetidos aos testes estatísticos de Kruskal-Wallis e Dunn. Foi possível concluir que o processo de reparo alveolar, aos 7, 15 e 30 dias, ocorreu de forma semelhante entre os grupos do coágulo sangüíneo, do sulfato de cálcio di-hidratado e da hidroxiapatita BTCP GenPhos, destacando-se a diferença significativa quanto à neoformação óssea, aos 15 dias, entre os grupos controle e hidroxiapatita BTCP GenPhos; e que, aos 30 dias, a evolução da neoformação óssea foi igual para todos os grupos analisados. / The evolution of bone repair was evaluated in tooth sockets of rats filled with blood clot as well as after placement of calcium sulfate dihydrate implant and hydroxyapatite BTCP GenPhos. The study sample was composed of 48 males rats divided into three groups, which were submitted to extraction of the right maxillary incisor. In group I, the sockets were filled with blood clot and were kept as such as control. Group II received a calcium sulfate dihydrate implant, and group III was submitted to placement of hydroxyapatite BTCP GenPhos in the sockets. At 7, 15 and 30 days after surgery, the animals were killed, the right hemimaxillae were removed and histologically processed for descriptive and quantitative microscopic analysis, whose results were statistically analyzed by the Kruskal-Wallis and Dunn tests. It was concluded that the alveolar repair process at 7, 15 and 30 days was similar for sockets filled with blood clot, calcium sulfate dihydrate and hydroxyapatite BTCP GenPhos, with emphasis to the significant difference with regard to new bone formation at 15 days between the control and hydroxyapatite BTCP GenPhos groups; and, at 30 days, the evolution of new bone formation was similar for all study groups

A preservação da arquitetura óssea alveolar, durante o processo de reparo do alvéolo dentário após exodontias, é um grande desafio clínico. É esperado que 40 a 60% do volume ósseo alveolar inicial sejam perdidos nos primeiros seis meses. O OsteoScaf é um novo substituto ósseo, desenvolvido pela Universidade de Toronto e representa uma alternativa promissora para a manutenção da integridade óssea alveolar nesse cenário. Esse material é uma matriz tridimensional trifásica reabsorvível e osteocondutiva, composta por ácido polilático-co-glicólico e duas fases de fosfato de cálcio reabsorvível. Com o objetivo de avaliar se o OsteoScaf poderia reduzir a perda óssea durante a fase de reparação/remodelação alveolar após a exodontia, quando comparado com o controle (apenas coágulo sanguíneo), foram implantados cilindros desse material (com duas porosidades diferentes - poros grandes e poros pequenos) em alvéolos de dentes anteriores superiores humanos, imediatamente após a exodontia. Dez pacientes (32 alvéolos) fizeram parte deste estudo, onde 16 alveólos receberam o implante de OsteoScaf e 16 foram usados como controle. Foram feitas tomografias computadorizadas de feixe cônico (TCFC) imediatamente após a exodontia e também aos 120 dias pós-operatóro, quando foram realizadas biópsias ósseas analisadas por microtomografia computadorizada (microTC) e microscopia. A análise quantitativa das microTCs mostraram mais trabéculas ósseas e menor espaço entre elas, com OsteoScaf de poros menores. A análise quantitativa das TCFC indicou menor perda óssea no grupo experimental, principalmente o OsteoScafTM de poros maiores. A avaliação qualitativa dos cortes histológicos mostrou neoformação óssea justaposta ao material, demonstrando sua natureza osteocondutiva. Nossas observações mostraram que o OsteoScaf (de poros pequenos ou grandes) reduziu a perda óssea alveolar durante o processo de reparação/remodelação óssea pós-exodôntica, aos 120 dias de pós-operatório, em humanos. Essa pesquisa recebeu apoio financeiro da CAPES (Brasil) e TRT (Canadá). / Preserving alveolar bone architecture during socket healing is a significant clinical challenge. It is expected that 40% to 60% of the initial alveolar bone volume will be lost up to 6 months after tooth extraction. OsteoScaf is a novel bone substitute material developed at the University of Toronto and represents a promising alternative for maintaining alveolar bone integrity in this clinical scenario. It is a resorbable, osteoconductive, 3-phase composite scaffold comprising poly(lactide-co-glycolide) and 2 osteoclast-resorbable calcium phosphate phases. Our hypothesis was that OsteoScaf lithomorphs (10x3mm cylinders), placed in fresh extraction sockets, would reduce post-extraction bone loss compared to sockets with coagulum alone (control). Thus, we placed OsteoScaf (of two different porosities small and large pores) in fresh extraction sockets of maxillary anterior teeth in humans. A total of 10 patients (32 sockets) were included in the study, of which 16 sockets were grafted with OsteoScaf and 16 were used as control. Cone Beam Computer Tomography (CBCT) was performed both immediately following extraction and also at 120 days postoperatively, at which time biopsy samples were also harvested for micro computer tomography (µCT) and histological analyses. Quantitative analysis of the µCT showed more bone trabeculae and smaller trabecular separation in the experimental group than control, specifically with small pore scaffolds. In addition, quantitative analysis of CBCT showed less bone resorption in the OsteoScafTM groups, especially with the large pore scaffolds. Qualitative histological analysis showed new bone tissue in direct apposition to the scaffold demonstrating its osteoconductive nature. Our observations showed that the OsteoScafTM groups (small and large pores) reduced alveolar bone loss after 120 days of socket healing in humans. Grants: CAPES (Brazil) and TRT (Canada).

Abstract available in The FASEB Journal.

Nitric oxide (NO) and carbon monoxide (CO) gases, alone or with oxalate, phytate, or ethylenediaminetetraacetate (EDTA) were tested for antibotulinal activity as substitutes for sodium nitrite in ground pork inoculated with spores of Clostridium botulinum, then abused by storage at 277°C. Nitric oxide with 250 ppm oxalate or phytate was most inhibitory, while NO alone was as effective as 156 ppm sodium nitrite for inhibition of gas and botulinal toxin production in the meat system. All swollen samples contained very low levels of residual nitrite, but nitroso heme and soluble iron content did not change compared with unswollen samples of the same treatment while total heme content decreased slightly. Binding iron in the meat system did not appear to be sufficient for botulinal inhibition. Apparently, residual nitrite must be present to react directly with the botulinal cell, inhibiting growth. NO gas would not be a practical subsitute for sodium nitrite in curing, since nitrite itself is formed when meat is blended in the presence of this gas. Neither could CO be used in meat curing, since the pink color of raw, CO-treated meat disappeared after cooking. More importantly, all samples treated with CO swelled rapidly and contained botulinal toxin.