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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Aderência, invasão e citotoxicidade de Aggregatibacter actinomycetemcomitans isolados de pacientes portadores de doença periodontal crônica e agressiva. / Adhesion, invasion and cytotoxicity of Aggregatibacter actinomycetemcomitans isolated from patients with chronic and aggressive periodontal disease.

Thais Cristiane Wahasugui 27 May 2013 (has links)
Aggregatibacter actinomycetemcomitans exerce um papel fundamental no desenvolvimento da doença periodontal crônica e agressiva. Produz fatores de virulência que o tornam capaz de colonizar e invadir os tecidos periodontais e de escapar das defesas do hospedeiro. Nesse estudo, foram determinadas as características fenotípicas e genotípicas de A. actinomycetemcomitans e a presença dos principais genes responsáveis por sua virulência. Amostras de biofilme subgengival de 65 indivíduos com doença periodontal e de 48 indivíduos sadios foram coletadas, sendo obtidos 73 isolados bacterianos. Testes de biotipagem, adesão, invasão e citotoxicidade às células orais (KB), produção de neuraminidase e biofilme, presença de cápsula e fimbrias foram avaliados, assim como, a presença dos genes flp-1 (relacionado à adesão); apaH (relacionado à invasão); promotor LTX e ltxA (produção de leucotoxina); e cdtA, cdtB, cdtC, cdtABC (produção de toxina distensora). O biotipo II foi o mais predominante nos isolados de A. actinomycetemcomitans. Sessenta e seis isolados foram capazes de aderir às células KB e dentre eles, 33 foram capazes de invadir as mesmas. Quarenta e seis isolados de A. actinomycetemcomitans foram citotóxicos às células KB, produzindo alterações na morfologia celular. Neuraminidase foi produzida por 60 dos isolados analisados, com títulos de aglutinação de 2 a 8. Cinquenta e quatro isolados foram capazes de formar grande quantidade de biofilme. Todos os isolados apresentaram cápsula, porém nenhum deles apresentou fímbrias. O gene flp-1 foi detectado em 40 isolados e o gene apaH em 52 isolados de A. actinomycetemcomitans. O promotor LTX e o gene ltxA foram encontrados em todos os isolados, sendo 64 altamente leucotóxicos e 9 fracamente leucotóxicos. O gene cdtA foi observado em 50 isolados testados; o gene cdtB, em 48 isolados; o gene cdtC, em 61 isolados e o gene cdtABC, em 40 isolados. Esses resultados sugerem que a maioria dos isolados clínicos de A. actinomycetemcomitans, provenientes de pacientes com periodontite, abrigam os principais genes responsáveis pela virulência, principalmente os relacionados à produção de toxinas. Possivelmente, a maioria dos isolados foram capazes de aderir às células orais e formar biofilmes em superfícies sólidas pelo envolvimento de outros tipos de adesinas, além das fímbrias. Além disso, dois dos três isolados de indivíduo sadio também apresentaram fatores de virulência que poderiam causar periodontite. / Aggregatibacter actinomycetemcomitans plays a key role in the development of chronic and aggressive periodontitis. This microorganism produces virulence factors which make it able to colonize and invade the periodontal tissues and escape from host defenses. In this study, the phenotypic and genotypic characteristics of A. actinomycetemcomitans and the presence of the main genes responsible for virulence were determined. Subgingival biofilm samples from 65 patients with periodontal disease and 48 healthy individuals were collected, and 73 bacterial isolates were obtained. Biotyping, adhesion, invasion and cytotoxicity to oral cells (KB), neuraminidase and biofilm production, presence of capsule and fimbriae were evaluated, as well as the presence of flp-1 (related to adhesion); apaH (related to invasion); LTX promoter and ltxA (leukotoxin production); cdtA, cdtB, cdtC, cdtABC (cytoletal distending toxin production) genes. Biotype II was the most prevalent in A. actinomycetemcomitans. Sixty-six isolates were able to adhere to KB cells and among them 33 were able to invade them. Forty-six A. actinomycetemcomitans isolates were cytotoxic to KB cells, producing changes in cell morphology. Neuraminidase was produced by 60 isolates, with agglutination titles of 2 to 8. Fifty-four A. actinomycetemcomitans were able to form large amount of biofilm. All isolates showed capsule, but not fimbriae. The flp-1 and apaH genes were detected, respectively, in 40 and 52 isolates. The LTX promoter and ltxA gene were found in all isolates, in 64 were highly leukotoxic and 9 minimally leukotoxic. The cdtA gene was observed in 50; cdtB in 48; cdtC in 61 and cdtABC in 40 A. actinomycetemcomitans. These results suggest that most of A. actinomycetemcomitans clinical isolates from periodontal patients, harbor the main genes responsible for virulence, especially those related to toxins production. Possibly, most of the isolates were able to attach to oral cells and form biofilms on solid surfaces, by the involvement of other types of adhesins, besides the fimbriae. Furthermore, two out three isolates from healthy individual also had virulence factors that could cause periodontitis.
322

Tratamento da distonia cervical com fisioterapia: estudo de 20 casos / Cervical dystonia and physical therapy: a case study of 20 subjects

Mariana Araujo Ribeiro Queiroz 21 May 2012 (has links)
INTRODUÇÃO: Apesar da terapia com toxina botulínica ser o tratamento de escolha para a distonia cervical, admite-se que um tratamento multidisciplinar, agregando a fisioterapia ao tratamento com toxina botulínica, poderia acrescentar maiores benefícios aos pacientes com distonia cervical; sendo assim, o objetivo primário deste estudo foi avaliar o efeito da associação da toxina botulínica a um protocolo de fisioterapia na gravidade da distonia cervical, incapacidade e dor; e o objetivo secundário foi avaliar o efeito desta associação na qualidade de vida de pacientes com distonia cervical. MÉTODOS: Participaram deste estudo controlado aberto quarenta de setenta pacientes com distonia cervical, tratados no Ambulatório de Distúrbios do Movimento do Departamento de Neurologia da Faculdade de Medicina do Hospital das Clínicas da Universidade de São Paulo. Antes de serem submetidos à aplicação da toxina botulínica, os pacientes foram avaliados por um médico da equipe, e esperava-se que neste dia os pacientes estivessem sem a ação da medicação. Todos os pacientes avaliados foram convidados a participar do programa de fisioterapia, e conforme a disponibilidade de aderir ao programa dos mesmos, chegou-se ao número de vinte pacientes em G1 (fisioterapia e toxina botulínica) e vinte pacientes em G2 (toxina botulínica), sendo esta amostra de conveniência. Para G2, foram escolhidos os primeiros vinte pacientes consecutivos que não poderiam aderir ao programa fisioterapêutico. Os pacientes de G1 e G2 foram reavaliados após quarenta e cinco dias. As escalas utilizadas foram a Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) e a Short-Form Health Survey (SF-36). Foi proposto um novo modelo de tratamento para pacientes com distonia cervical que seriam submetidos a um protocolo fisioterapêutico, baseado em três principais abordagens: aprendizagem motora, cinesioterapia e estimulação elétrica funcional na musculatura antagonista ao padrão distônico. Os pacientes de G1 foram tratados por um período de quatro semanas, a frequência era diária (cinco vezes por semana) e a duração da sessão em média uma hora e quinze minutos. RESULTADOS: As características demográficas iniciais dos indivíduos não diferiram significativamente entre os dois grupos tratados, em apenas um dos itens avaliados (tempo de tratamento) houve diferença entre grupos no momento inicial. Os resultados dos tratamentos na qualidade de vida foram avaliados pela escala SF-36, esta dividida em dois grandes domínios: aspectos físicos e aspectos emocionais. Em relação aos aspectos físicos, G1 apresentou melhora significativa comparando-se antes e depois do tratamento (intragrupo) em três subdomínios: capacidade funcional, limitação por aspectos físicos e dor; em G2 não houve melhora significativa em nenhum dos quatro subdomínios. Houve também uma diferença entre G1 e G2 depois dos tratamentos (entre grupos) em dois subdomínios: limitação por aspectos físicos e dor. Em relação aos aspectos emocionais, em G1, houve melhora significativa nos seguintes subdomínios depois do tratamento (intragrupo): vitalidade, aspectos sociais e saúde mental. Houve também uma diferença entre G1 e G2 depois dos tratamentos (entre grupos) em dois subdomínios: vitalidade e saúde mental. Não houve melhora em G2 nos subdomínios dos aspectos emocionais. A avaliação das características e gravidade da distonia cervical, medida pela TWSTRS, demonstrou melhora significativa de G1 e G2 após os tratamentos que foram submetidos (intra grupos) em duas subescalas: gravidade (I) e incapacidade (II). Na subescala de dor (III), apenas G1 apresentou melhora intragrupo após o tratamento a que foi submetido; houve também, neste mesmo subdomínio, diferença significativa entre G1 e G2 depois dos tratamentos, entre grupos. CONCLUSÕES: O presente estudo avaliou possibilidade de que a utilização da toxina botulínica, junto a um protocolo de fisioterapia facilmente reprodutível, poderia agregar melhoras em sintomas como gravidade da doença, incapacidade, dor e qualidade de vida de uma população de indivíduos com distonia cervical, e os resultados obtidos permitiram negar as hipóteses nulas. Novas pesquisas são necessárias para confirmar esses achados e solidificar a reabilitação neurológica como um tratamento eficaz no manejo da distonia cervical / INTRODUCTION: Despite the fact that therapy with botulinum toxin is considered the best treatment for cervical dystonia, it is assumed that a multidisciplinary treatment, adding physical therapy to the botulinum toxin treatment could provide additional gains to patients with cervical dystonia. The primary objective of this study was to evaluate the effect of the combination of botulinum toxin and physical therapy on severity of cervical dystonia, disability and pain. The secondary objective was to evaluate the effect of this combination on the quality of life in patients with cervical dystonia. METHODS: forty patients of seventy with cervical dystonia from the Ambulatório de Distúrbios do Movimento do Departamento de Neurologia da Faculdade de Medicina do Hospital das Clínicas da Universidade de São Paulo attended this open- controlled study. Before receiving an application of botulinum toxin, the patients were evaluated by a neurologist and it was assumed that patients were not under any effect of the medication (botulinum toxin). All patients were asked to participate in a physical therapy program, and according to the patients availability to join the program, we reached the number of twenty patients in G1 (physical therapy and botulinum toxin) and in G2 (botulinum toxin only), the first twenty consecutive patients who couldnt participate in the physical therapy program were chosen. This was a convenience sample. Patients of G1 and G2 were revaluated after forty five days, and the evaluation scales used was the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Short-Form Health Survey (SF-36). A new model of physical therapy treatment was applied to patients with cervical dystonia, and it was based on three main approaches: motor learning, kinesiotherapy and functional electrical stimulation on the antagonist muscles of the dystonic pattern. The patients in G1 were treated daily for a period of four weeks, and each session lasted one hour and fifteen minutes. RESULTS: The demographic characteristics of individuals didnt differ significantly between two treated groups, but there was a difference between groups in the initial moment (baseline) in only one feature evaluated (time of treatment). The SF-36 scale was used to evaluate the results of the treatments for quality of life, and was divided into two big domains: physical and emotional aspects. When analyzing physical aspects, G1 showed a significant improvement when comparing before and after the proposed treatment (inside group) in three subdomains: physical functioning, role-physical and body pain; in G2 there was no improvement in any of the four subdomains. A difference between G1 and G2, after the treatments (between groups), was also seen in two subdomains: role-physical and body pain. In relation to emotional aspects, in G1, after the treatment (intra-group), there was a significantly improvement in vitality, social functioning and mental health. There was also a difference between G1 and G2 after the treatment (between groups) in two subdomains: vitality and mental health. There was no improvement in G2 in any domains of the social aspects. Severity of cervical dystonia showed a significant improvement of G1 and G2 after treatments (intra-group) in two subdomains: severity (I) and disability (II). In subscale pain (III), only patients of G1 showed a significant improvement intra-group after the treatment; in this subdomain there was also a significant difference between groups after the treatments (G1 and G2). CONCLUSIONS: The present study showed that botulinum toxin, combined with an easily reproducible physical therapy protocol, could improve symptoms like severity of cervical dystonia, disability, pain and quality of life, in a population of individuals with cervical dystonia, and these results makes it possible to deny the null hypothesis. Other studies are needed to confirm these findings and solidify neurologic rehabilitation as an effective cervical dystonia treatment approach
323

Avaliação da eficácia e segurança da toxina botulínica tipo A na indução da ptose temporária em cães / Evaluation of the efficacy and safety of botulinum toxin type A to induce temporary ptosis in dogs

Bittencourt, Maura Krähembuhl Wanderley, 1979- 26 August 2018 (has links)
Orientador: José Paulo Cabral de Vasconcellos / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T03:03:06Z (GMT). No. of bitstreams: 1 Bittencourt_MauraKrahembuhlWanderley_D.pdf: 4949840 bytes, checksum: 022f99304656d76ae232d1c85d47077b (MD5) Previous issue date: 2014 / Resumo: Objetivo: Descrever a ação da toxina botulínica do tipo A quando aplicada no músculo elevador da pálpebra superior, investigar a sua segurança e eficácia na produção de ptose protetora em cães. Métodos: Neste estudo do tipo longitudinal, série de casos com intervenção, um total de 10 cães foram submetidos à quimiodenervação do músculo elevador da pálpebra superior, através da aplicação por via transcutânea de 15 unidades de toxina botulínica do tipo A. Alterações sistêmicas, mobilidade ocular, função visual, pressão intraocular, produção lacrimal, o aparecimento, grau e duração da ptose foram avaliados diariamente durante os sete primeiros dias e posteriormente nos dias 14, 21 e 28 após a aplicação. Resultados: O início do efeito clínico foi observado entre 2 e 3 dias após a aplicação da toxina, o tempo necessário para desenvolver a máxima ptose variou entre 4 e 7 dias (média de 5 dias), a duração média do efeito da toxina foi de 21 dias. O percentual médio de redução máxima do tamanho da fenda palpebral foi 42,9 % (DP ± 35,7%). Não houve diferença estatisticamente significativa na pressão intraocular antes e depois da aplicação da toxina (P = 0,974 ), bem como na avaliação da produção lacrimal (P = 0,276). Não houve alteração na mobilidade ocular e nenhum outro efeito adverso foi observado em associação com a administração do medicamento em estudo. Conclusão: A aplicação da toxina botulínica do tipo A no músculo elevador da pálpebra superior em cães foi eficaz e segura para promover a ptose protetora com uma cobertura temporária da córnea / Abstract: Purpose: Describe the action of botulinum toxin type A when applied into levator palpebral superioris muscle, verifying its safety and efficacy to promote protective ptosis in dogs. Methods: In this prospective interventional study, a total of 10 dogs underwent transcutaneous anterior chemodenervation of levator palpebral superioris with 15 units of botulinum toxin type A. The systemic changes, ocular mobility, visual function, intraocular pressure (IOP), tear production and the onset, degree and duration of ptosis were evaluated on a daily basis during the first seven days and on days 14, 21 and 28 after application. Results: The onset of the clinical effect was observed between 2 and 3 days after application of the toxin, the time taken for maximum ptosis develop varied from 4 to 7 days (mean 5 days), average duration of the toxin effect was 21 days. The mean percentage reduction in palpebral fissure height was 42.8% (SD ± 35.7%). There was not a statistically significant difference in IOP before and after the BoNT/A application (P = 0.974), or lacrimal production evaluation (P = 0.276). There was no change in ocular mobility and no other adverse effect was observed in association with the administration of the study drug. Conclusion: The application of botulinum toxin type A into levator palpebral superioris muscle in dogs was effective and safe to promote protective ptosis with a temporary covering of the cornea / Doutorado / Ciencias Biomedicas / Doutora em Ciências Médicas
324

Transcriptoma da glândula venenífera da serpente Bothrops alternatus (urutu) e caracterização molecular e bioquímica parcial da dipeptidilpeptidase IV / Venom gland transcriptomic of the snake Bothrops alternatus (urutu) and partial molecular and biochemical characterization of the dipeptidyl peptidase IV

Cardoso, Kiara Carolina, 1979- 19 August 2018 (has links)
Orientador: Stephen Hyslop / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T08:32:10Z (GMT). No. of bitstreams: 1 Cardoso_KiaraCarolina_D.pdf: 27750375 bytes, checksum: a1ca027909bfd58421b986e75bfcd515 (MD5) Previous issue date: 2011 / Resumo: O estudo do transcriptoma de bibliotecas de cDNA da glândula venenífera de serpentes, realizado a partir da análise de ESTs (expressed sequence tags), tem se mostrado útil na identificação de genes expressos neste tecido, inclusive no gênero Bothrops, responsável pela maioria dos acidentes ofídicos no Brasil. Neste trabalho utilizamos uma abordagem transcriptômica para analisar a composição gênica da glândula venenífera da serpente Bothrops alternatus, uma espécie encontrada no sudeste e sul do Brasil, Uruguai, norte da Argentina e leste do Paraguai. Também clonamos e caracterizamos parcialmente a enzima dipeptidilpeptidase IV (DPP IV), uma enzima que cliva peptídeos com prolina ou alanina na penúltima posição em sua porção N-terminal e que tem sido detectada em diversas peçonhas ofídicas. A construção de bibliotecas de cDNA usando métodos convencionais de clonagem, sequenciamento e análise bioinformática resultou em 5,350 ESTs que foram reunidas em 838 contigs and 4512 singletons. Pesquisas a partir de bancos de dados relevantes (BLAST) mostraram 30% de hits e 70% no-hits. Os transcritos relacionados a toxinas correspondem a 23% do total de transcritos e 78% dos hits, respectivamente. A análise por ontologia gênica (GO) detectou genes relacionados ao metabolismo geral, transcrição, tradução, processamento, degradação de polipeptídeos, funções estruturais, e regulação celular. Os principais grupos de toxinas identificados foram metaloproteinases (81%), peptídeos potenciadores da bradicinina/peptídeos natriuréticos do tipo C (8,8%), fosfolipases 'A IND. 2' ('PLA IND. 2'; 5,6%), serinoproteinases (1.9%) e lectinas do tipo C (1,5%). As metaloproteinases eram quase queexclusivamente da classe PIII, com poucas da classe PII e nenhuma da classe PI. As 'PLA IND. 2' eram todas ácidas; nenhuma 'PLA IND. 2' básica foi detectada. Outras toxinas encontradas incluíram a L-aminoácido oxidase, proteínas secretadas ricas em cisteína, DPP IV, hialuronidase, toxinas three-finger e ohanina. Foram identificadas duas proteínas não-tóxicas, a tioredoxina e a Dusp6 (fosfatase de dupla especificidade) que mostraram alto grau de similaridade a proteínas semelhantes de outras serpentes. Também foram observados polimorfismos de nucleotídeos únicos (SNPs - single-nucleotide polymorphisms), microssatélites, transposons e repetições invertidas, todos os quais podem contribuir de alguma forma para a multiplicidade de toxinas na glândula. Estes resultados mostram que a glândula venenífera de B. alternatus possui as principais classes de toxinas encontradas em estudos transcriptômicos e proteômicos de outras espécies botrópicas. ... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Transcriptomic studies of snake venom gland cDNA based on the analysis of expressed sequence tags (ESTs) have been useful in identifying the genes expressed in this organ in a variety of species, including the genus Bothrops, which is responsible for most venomous snakebites in Brazil. In this work, we used a transcriptomic approach to analyze the gene composition of the venom gland of Bothrops alternatus (urutu), a species found in southeastern and southern Brazil, Uruguay, northern Argentina e eastern Paraguay. We also cloned and partially characterized dipeptidylpeptidase IV (DPP IV), an enzyme that cleaves peptides with proline or alanine as the penultimate residue in the N-terminal region and has been identified in several snake venoms. A cDNA library constructed using conventional methods of cloning, sequencing and bioinformatic analysis yielded 5,350 ESTs that formed 838 contigs and 4512 singletons. Databank BLAST searches yielded 30% hits and 70% no-hits. Toxin-related transcripts accounted for 23% of the total transcripts and 78% of the hits. Gene ontology analysis detected genes related to general metabolism, transcription, translation, processing, polypeptide degradation, structural functions and cellular regulation. The main toxin groups identified were metalloproteinases (81%), bradykinin-potentiating peptides/C-type natriuretic peptides (8.8%), phospholipases 'A IND. 2' ('PLA IND. 2'; 5.6%), serine proteinases (1.9%) and C-type lectins (1.5%). Metalloproteinases were almost exclusively class PIII, with few class PII and no class PI enzymes. The 'PLA IND. 2' were all acidic; no basic 'PLA IND. 2' were detected. Other toxins identified included L-amino acid oxidase, cysteine-rich secretory proteins, DPP IV, hyaluronidase, three-finger toxins and ohanin. Two non-toxic proteins, thioredoxin and a dual specificity phosphatase (Dusp6), shared high sequence homology with similar proteins from other snakes. Single-nucleotide polymorphisms (SNPs), microsatellites, transposons and inverted repeats were also observed and may contribute to the toxin diversity of the gland. These results show that the venom gland of B. alternatus contains the major toxin classes identified in transcriptomic and proteomic studies of other Bothrops species. The predominance of class PIII metalloproteinases agrees with the hemorrhagic activity of this venom, while the low content of serine proteinases and C-type lectins could account for the less intense coagulopathy observed after envenoming by this species. The lack of basic 'PLA IND. 2' agrees with the lower myotoxicity of this venom compared to other Bothrops species. ... Note: The complete abstract is available with the full electronic digital thesis or dissertations / Doutorado / Farmacologia / Doutor em Farmacologia
325

Avaliação de métodos e ocorrência de Clostridium difficile em carnes / Evaluation of methods and occurrence of Clostridium difficile in meats

Tsuchiya, Ana Claudia, 1987- 04 September 2012 (has links)
Orientador: Arnaldo Yoshiteru Kuaye / Dissertação (mestrado) - Universidade Estadual de Campionas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-20T10:25:27Z (GMT). No. of bitstreams: 1 Tsuchiya_AnaClaudia_M.pdf: 449310 bytes, checksum: 3afe68453ac7a3b16148cef90be5c03f (MD5) Previous issue date: 2012 / Resumo: Clostridium difficile é um bacilo anaeróbio responsável por doença intestinal associada ao tratamento prévio com antibióticos, manifestando desde uma diarreia leve até casos graves de colite pseudomembranosa causada principalmente pelas toxinas A (TcdA) e B (TcdB). Os casos de infecção estão relacionados à contaminação em hospitais, porém pesquisas recentes sugerem possível associação ao consumo de alimentos contaminados, pois C. difficile já foi isolado de bovinos, suínos e aves e suas carnes sugerindo os animais como reservatórios. Desta forma, os estudos são de suma importância para o entendimento da transmissão da doença causada por C. difficile. Diante de poucas pesquisas de C. difficile e da inexistência de método padronizado para seu isolamento a partir dos alimentos, o trabalho consistiu em três etapas: 1) avaliação de metodologia [utilizando dois procedimentos (tratamento com álcool e plaqueamento direto) e dois meios seletivos (ágar Clostridium difficile moxalactan norfloxacina ¿ CDMNA e ágar cicloserina cefoxitina frutose ¿ CCFA)] de detecção de C. difficile em carnes (bovina moída e peito de frango [Peitoralis profundus e superficialis]); 2) avaliação da ocorrência de C. difficile em amostras de carnes resfriadas (bovina moída, bovina peça [Semimembranosus], suína [Longuisimus dorsi] e frango [Peitoralis profundus e superficialis]), compreendendo detecção, isolamento e identificação dos isolados; 3) avaliação do perfil toxigênico dos isolados através da detecção de genes tcdA e tcdB codificadores de TcdA e TcdB e respectivamente avaliação de produção do toxinas pelos isolados. A partir da comparação de dois procedimentos, observou-se que o plaqueamento direto foi mais eficaz e recuperou uma maior quantidade de C. difficile se comparado com o tratamento com álcool e o ágar Clostridium difficile moxalactan norfloxacina (CDMNA) apresentou maior taxa de recuperação em relação ao ágar cicloserina cefoxitina frutose (CCFA). A ocorrência de C. difficile foi observada em 11,5% (17/147) das amostras analisadas, totalizando 80 isolados, destes 41,2% (33/83) apresentaram positivo para pelo menos um gene de virulência (A-B+), ou para ambos os genes (A+B+). Houve concordância de 70,5% entre os testes fenotípicos e genotípicos utilizados para detecção de toxinas. Desta forma, sugere-se que alimentos de origem animal são uma potencial fonte de transmissão de C. difficile para humanos / Abstract: Clostridium difficile is an anaerobic bacillus responsible for intestinal deseases in individuals previouslly treated with antibiocs, who can manifest from a mild diarrhea to severe cases of pseudomembranous colitis, mainly caused by toxins A (TcdA) and B (TcdB). The infections are related to contamination in hospitals, but recent researches sugests a possible association with the consumiption of contaminated foods as C. difficile has been isolated from bovines, suines and poultries and their meat, sugesting animals as reservatories. Thus, studies are extremelly important to elucidate the transmition of the desease caused by C. difficile. Faced with few researches about this bacteria and the lack of a standard method for its isolation from food, this work is divided in three steps: 1) Evaluation of the methodology for C. difficile detection in meet (commercial bovine mince and chicken breast ¿ [Peitoralis superficialis and Peitoralis profundus] [using two procedures (treatment with alcohol and direct plating) and two selective mediums (agar Clostridium difficile moxalactan norfloxacin ¿ CDMNA and cycloserine cefoxitin fructose agar¿ CCFA)]; 2) Assessing of the occurrence of C. difficile in samples of chilled meat (bovine: commercial mince and the whole Semimembranosus; suine: whole Longuisimus dorsi; chicken: Peitoralis profundus and Peitoralis superficialis) by detection, isolation and identification of the isolated; 3) Evaluation of the toxicogenic profile of the isolated by the detection of the genes tcdA and tcdB, which are encoding of TcdA and TcdB respectivelly, and the capacity of toxine production by the isolated bacterias. From the comparison of the two proceeding above it was observed that the direct plating was more efficient and recovered a larger aumont of C. difficile than the treatment with alcohol. Furthermore, the CDMNA agar presented a higher recovery rate compared to CCFA agar. It was observed the occurrence of C. difficile in 11,5% (17/147) of the analyzed samples, comprising 80 isolates, of which 41,2% (33/83) showed a positive response for at least one virulence gene (A-B+), or for both genes (A+B-). In addition, there was a 70,5% concordance between the phenotypic and genotypic tests used to detect toxins. In this way, it is suggested that foods of animal origin are a potential source of transmission of C. difficile for humans / Mestrado / Tecnologia de Alimentos / Mestre em Tecnologia de Alimentos
326

Bygg- och rivningsavfall- Hanteras kakel och klinker på rätt sätt? / Construction- and demolition wasteAre tile and clinker handled correctly?

Läckgren, Robin, Osama, Yesen January 2014 (has links)
Inom byggbranschen omsätts stora mängder byggavfall. Avfallet är svårt att hantera för att det består av så stora mängder. Restavfall som kommer från en byggarbetsplats källsorteras. Avfall från byggnation och rivning innehåller många olika typer av miljöfarliga ämnen, vilket förorsakar miljöföroreningar. Farliga ämnen riskerar att läcka ut i marken och ut i naturen. Branschen har funderat på om kakel och klinkers verkligen deponeras på rätt sätt idag från byggavfall och rivning. Syftet med arbetet var att undersöka om kakel och klinkers innehåller metaller som kan vara miljöfarliga. Halterna i ytskikten uppmättes och genom att utföra laktester kunde vi analysera avgivningen från materialen i olika miljöer. Det visade sig att kakel och klinker innehåller höga halter av metaller som kan läcka ut till omgivningen vid lågt pH-värde. Slutsatsen från laktesterna är att om kakel och klinker hanteras på rätt sätt i neutral eller basisk miljö är det inte miljöfarligt, eftersom samtliga utlakningsvärden vid pH åtta till tio låg inom gränserna. Men vi ser en fara om kakel och klinker hamnar i en sur miljö som har ett lågt pH runt fem till sex. Då är kakel och klinker inte inert avfall och skall alltså inte hanteras som det. Detta gör att kakel och klinker inte bör användas som till exempel fyllnadsmassor, utan att det bör deponeras som det görs idag. Arbetet bygger till stor del på diskussioner och samtal med Structor i Örebro och MTM på Örebro Universitet. / The construction industry deals with large quantities of construction waste. The waste is difficult to manage because of large amounts. Residual waste that comes from a construction site is recycled. Waste from construction and demolition includes many different types of pollutants causing environmental pollution. Hazardous substances likely to leach into the soil and into the wild. Structor have been thinking about if tile and clinkers tiles really are deposited in the right way today from construction waste and demolition. The purpose of this work is to investigate whether tile and clinker contains metals that can be harmful to the environment. The contents in the surface layers were measured and by performing leaching tests, we could analyze the leakage from materials in different surroundings. The samples proved that tile and clinker have high level of metals in the materials that can be given off to the environment at low pH. The conclusion from the leaching tests is that if the tiles are handled properly in the neutral or alkaline environment, it is not harmful to the environment because all results of leaching tests at pH values between eight and ten were within limits. But we see a danger if tiles end up in an acidic environment that has a low pH of around five to six. Then the tiles are not inert waste and therefore should not be handled like that. Tiles should thus not be used to such as aggregate, but it should be deposited as is done today. The work is largely based on discussions and conversations with Structor in Örebro and MTM at Örebro University.
327

Bioaccumulation and histopathology of copper in Oreochromis mossambicus

Naigaga, Irene January 2003 (has links)
Cu is one of the most toxic elements that affect fish populations when the fish are exposed to concentrations exceeding their tolerance. To investigate the effects of elementary Cu on aspects of bioconcentration, histology and behaviour, O. mossambicus were exposed to 0 and 0.75 ± 0.20 mg/l of Cu for 96 hours (short-term study), and 0, 0.11 ± 0.02, 0.29 ± 0.02, and 0.47 ± 0.04 mg/l of Cu for 64 days (longterm study) under controlled conditions in the laboratory. For the long-term study fish were sampled for gills, liver, and kidney Cu accumulation analysis after 1, 32 and 64 days of exposure and after 1, 2, 4, 16, 32, and 64 days for gills, liver and spleen histology analysis. Cu accumulation was concentration-duration dependent with the highest accumulation capacity in the liver. A multifactor linear model was developed for the relationship between exposure dose, exposure duration and Cu accumulation in the organs with the liver model: Log L = 3.35 + 0.85W + 0.31T (r² = 0.892) giving a better fit than the gills: G = −35.09 + 10.58W + 17.58T (r² = 0.632). Where L = Cu accumulation values in the liver, G = Cu accumulation values in the gills (both in μg/g dry mass); W = exposure dose in water (mg/l); and T = exposure time (days). Using this model Cu accumulation in organs can be estimated when exposure concentration and duration is known. This model should be tested under different conditions to determine the potential of the model in monitoring Cu toxicity in the environment. Lesions were observed in the liver, gills and spleen in all Cu treatments at all exposure concentration and exposure durations. However, the incidence and the degree of alteration was related to the concentration of Cu and duration of exposure. The sequential appearance of lesions in the order of, hepatic vacuolar degeneration, fatty degeneration and necrosis indicated a gradual increase in liver damage with larger duration of exposure time and increasing Cu concentration. The initial lesions in the gills were manifested as hypertrophy and hyperplasia of the gill epithelium causing increase in the thickness of the secondary lamellae, mucous cell hypertrophy and proliferation, mucous hypersecretion, proliferation of eosinophilic granule cells and hyperplasia of interlamellar cells. With increase in exposure time, necrosis of the eosinophilic granule cells, lamellar oedema, epithelial desquamation and increase in severity of lamellar hyperplasia were observed. These lesions indicated an initial defence mechanism of the fish against Cu toxicity followed by advanced histological changes that were related to Cu concentration and duration of exposure. Changes in the spleen were haemosiderosis, increase in the white pulp and macrophage centres, reduction in the red pulp, and necrosis suggesting that fish exposed to environmentally relevant levels of Cu may be histopathologically altered leading to anaemia and immunosuppression. Regression analysis was used to quantify the relationship between the total activity of the fish, and duration of exposure. There was a gradual decline in fish activity related to Cu concentration and duration of exposure before introducing food into the tanks. There was a constant activity after introducing food in the tanks at the control and 0.11 ± 0.02 mg/l Cu exposure levels irrespective of exposure time. Analysis of covariance (ANCOVA) was used to test for the difference in slopes between treatments. There was no significant difference (p > 0.05) between slopes of the control and 0.11 ± 0.02 mg/l Cu, and between 0.29 ± 0.02 and 47 ± 0.04 mg/l Cu before and after introducing food in the tanks. The slopes of both the control and 0.11 ± 0.02 mg/l Cu were significantly different from those of 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu (p < 0.05). There were significant differences in the mean opercular movements per minute between treatments (p < 0.05). There was hyperventilation at 0.11 ± 0.02 mg/l Cu i.e. 87 ± 18 opercular movements per minute (mean ± standard deviation) and hypoventilation at 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu i.e. 37 ± 34 and 13 ± 6 opercular movements per minute compared to the control. Hypo- and hyperventilation were related to the lesser and greater gill damage, respectively. In conclusion Cu accumulation and effects on histology of the liver, gills and were related to the concentration of Cu in the water and duration of exposure showing a gradual increase in incidence and intensity with larger duration of exposure time and increasing Cu concentration. The fish were initially able to homeostatically regulate and detoxify Cu. However, as the exposure continued, the homeostatic mechanism appears to have failed to cope with the increasing metal burden causing advanced histological changes.
328

An investigation into the effects of inorganic toxins and tryptophan metabolites on the forebrain cholinergic system and the pineal gland of the rat

Mahabeer, Rajeshree January 1997 (has links)
As soon as the building of the body is completed, the ageing process begins. In the natural course of events, the functioning of some organ systems finally ebbs below the threshold necessary to maintain the body, resulting in death. This occurrence is relatively rare, because diseases superimpose themselves upon the ageing process, bringing premature death resulting from pathological causes. This study focused on the cholinergic system of the rat forebrain. The cholinergic neurons in the brain are said to be involved in memory and learning, and a decrease in the activity of its enzymes has been reported in certain diseases, such as Alzheimer's disease. In the present study, the in vitro effects on the cholinergic system, of aluminium and mercury and tryptophan metabolites, kynurenic acid and quinolinic acid, are determined. Aluminium has been considered as a possible factor in Alzheimer's disease. Mercury in high concentrations is toxic, and its use in amalgam for dental treatment is under consideration with regard to its possible role in promoting neurological disease. The tryptophan metabolites increase in the brain with age and may have a role in pathological diseases. Quinolinic acid, when administered in toxic concentrations produces a possible model for Huntington's disease. This study investigated the effects of the above mentioned toxins on: (1) The synthesis of acetylcholine by choline acetyltransferase; (2) The specific binding of acetylcholine muscarinic receptors; (3) The degradation of acetylcholine by acetyl cholinesterase, Choline acetyltransferase activity did not change in the presence of aluminium chloride, kynurenic acid and quinolinic acid from 1 nM to 1 mM. Mercuric chloride had no significant effect on the enzymes activity from a concentration of 1 nM- 1 pM. At 10 pM there was a significant decrease in cholineacetyltransferase activity (P < 0.001). Enzyme activity continued to decrease at 100 pM (P < 0.0002). At 1 mM, enzyme activity was virtually non existent (P < 0.0001). Acetyl cholinesterase activity was not affected by aluminium chloride, kynurenic acid and quinolinic acid. Mercuric chloride from 1 pM - 1 mM significantly reduced the enzyme activity (P < 0.05). The binding of the antagonist, [³H] quinuclidinyl benzilate (QNB), to acetylcholine muscarinic receptors, revealed that aluminium chloride did not affect the binding of the antagonist, in the concentration range of 1 nM - 100 pM, to the receptors. At 1 mM, aluminium chloride appears to increase the sensitivity of the receptors for the ligand (P < 0.01). Mercuric chloride also does not appear to have any significant effect on receptor binding in this range. However, at 1 mM there appears to be a very significant decrease in receptor binding (P < 0.01). This decrease may be attributed to the interaction of mercury with the sulfhydryl groups in muscarinic receptors. Kynurenic acid had no effect on the receptor binding. Quinolinic acid, in the concentration range from 10 nM - 1 mM increased the binding ofthe receptor to [3Hi QNB significantly (P < 0.001). The study also investigated the effect of the tryptophan metabolites of the kynurenine pathway on pineal indole metabolism. The kynurenine pathway is a major route of tryptophan metabolism in the pineal gland, along with indole metabolism. Investigations showed that kynurenic acid produced a decrease in N-acetylserotonin concentrations ( P < 0.001) and melatonin concentrations (P < 0.003). Further experiments using quinolinic acid produced a similar decrease in N-acetylserotonin (P < 0.001) and melatonin (P < 0.015). A decrease was also noted in the level of 5-methoxytryptophol (P < 0.0005). These findings suggest that aluminium chloride, kynurenic acid and quinolinic acid have no possible role in the decrease of activity of cholinergic enzymes which is observered in diseases such as Alzheimer's disease. The results regarding the effect of mercury chloride on the cholinergic system suggest that low exposure to the toxin will not adversely effect the enzymes. The decrease in N-acetylserotonin and melatonin concentrations reported here, may be a result of kynurenic acid and quinolinic acid having an inhibitory effect on the enzyme, serotonin Nacetyltransferase, which is responsible for the conversion of serotonin to N-acety/serotonin.
329

Interactions of Toxic Metals with Algal Toxins Derived from Harmful Algal Blooms

Li, Shuo 24 October 2011 (has links)
The purposes of this study were to characterize the complexation of toxic metals with algal toxins and to determine the effects of arsenic and copper on the growth of Karenia brevis under specific experimental conditions. Microcystins, pahayokolides, brevetoxins and okadaic acid were used as representatives of algal toxins while arsenic, copper, cadmium, cobalt, iron, manganese and mercury were selected as typical toxic metals (including metalloids here) in the aquatic environment. The stabilities of the toxin-metal complexes were determined using equilibrium dialysis and/or centrifugal ultrafiltration technique. A direct exposure of arsenic and copper to the K. brevis was carried out to determine the effects of these metals to the growth of the algal cell. The results indicated that Cu2+, Hg2+, Co2+, Cd2+ and Fe2+ were capable of complexing with the algal toxins. Moreover, the exposure experiments demonstrated that the high concentration of arsenic and copper could affect the growth of the K. brevis.
330

Contribution of Lipophilic Secondary Metabolites to the Toxicity of Strains of Freshwater Cyanobacterial Harmful Algal Blooms, Identified Using the Zebrafish (Danio rerio) Embyo as a Model for Vertebrate Development

Jaja-Chimedza, Asha D 21 March 2014 (has links)
Cyanobacteria (“blue-green algae”) are known to produce a diverse repertoire of biologically active secondary metabolites. When associated with so-called “harmful algal blooms”, particularly in freshwater systems, a number of these metabolites have been associated - as “toxins”, or commonly “cyanotoxins” - with human and animal health concerns. In addition to the known water-soluble toxins from these genera (i.e. microcystins, cylindrospermopsin, and saxitoxins), our studies have shown that there are metabolites within the lipophilic extracts of these strains that inhibit vertebrate development in zebrafish embryos. Following these studies, the zebrafish embryo model was implemented in the bioassay-guided purification of four isolates of cyanobacterial harmful algal blooms, namely Aphanizomenon, two isolates of Cylindrospermopsis, and Microcystis, in order to identify and chemically characterize the bioactive lipophilic metabolites in these isolates. We have recently isolated a group of polymethoxy-1-alkenes (PMAs), as potential toxins, based on the bioactivity observed in the zebrafish embryos. Although PMAs have been previously isolated from diverse cyanobacteria, they have not previously been associated with relevant toxicity. These compounds seem to be widespread across the different genera of cyanobacteria, and, according to our studies, suggested to be derived from the polyketide biosynthetic pathway which is a common synthetic route for cyanobacterial and other algal toxins. Thus, it can be argued that these metabolites are perhaps important contributors to the toxicity of cyanobacterial blooms. In addition to the PMAs, a set of bioactive glycosidic carotenoids were also isolated because of their inhibition of zebrafish embryonic development. These pigmented organic molecules are found in many photosynthetic organisms, including cyanobacteria, and they have been largely associated with the prevention of photooxidative damage. This is the first indication of these compounds as toxic metabolites and the hypothesized mode of action is via their biotransformation to retinoids, some of which are known to be teratogenic. Additional fractions within all four isolates have been shown to contain other uncharacterized lipophilic toxic metabolites. This apparent repertoire of lipophilic compounds may contribute to the toxicity of these cyanobacterial harmful algal blooms, which were previously attributed primarily to the presence of the known water-soluble toxins.

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