Thesis (Ph. D.)--University of Washington, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 1998. / Includes bibliographical references.

Made available in DSpace on 2015-01-26T13:21:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2000-06-16Bitstream added on 2015-01-26T13:30:29Z : No. of bitstreams: 1 000127963.pdf: 2973395 bytes, checksum: bf77aed8dd9ecaabebd918b848ba341a (MD5) / O objetivo deste estudo foi avaliar a influência da tetraciclina administrada a ratas prenhas no desenvolvimento hepático e renal de filhotes. Foram utilizadas quinze ratas sendo três controles e 12 tratadas. As ratas controle receberam injeções de solução fisiológica, enquanto as dos grupos experimentais foram tratadas com cloridrato de tetraciclina nas doses de 25, 50, 75 e 100mg/kg, via intraperitoneal, em dose única, no décimo dia da gestação. Os filhotes foram sacrificados ao nascer, com dez, vinte e trinta dias de vida. A análise histológica do fígado mostrou vacuolização, necrose, inflamação e dilatação sinusoidal principalmente em recém-nascidos. Mitoses, aumento precoce da população de células de Kupffer, hipertrofia de hepatócitos com maior síntese de glicogênio foram mais acentuadas nos filhotes com dez e vinte dias. No rim verificamos vacuolização tubular e necrose discretas, que ficaram mais evidentes nos recém-nascidos, e sinais de regeneração tubular aos dez e vinte dias. Os resultados sugerem que os órgãos estudados sofreram alterações morfológicas transitórias durante o desenvolvimento, mas revelaram indícios de regeneração ao longo do tempo / This study aims to evaluate the possible effects of tetracycline administered to pregnant rats on kidney and liver development of their offspring. Fifteen rats were used - three controls and twelve treated ones. The control group received saline injections while the experimental groups were administered tetracycline chlorhidrate in the doses of 25, 50, 75 and 100mglkg, intraperitoneally, in a single injection, on the tenth day of pregnancy. The sucking were sacrificed at birth and after ten, twenty and thirty days of life. The liver specimes showed vacuolizations, necrosis, inflammation and sinusoidal dilatations, more evident in the newborn. Mitosis, early increase of Kupffer cells population and hypertrophy of hepatocytes with greater synthesis of glycogen were present in the 10th and twentieth days of life. The kidney specimens showed slight tubular vacuolizations and necrosis, more prominent in the newbom, as well as signs of tubular regeneration at the tenth and twentieth days. These results suggest that the organs studied went through several transitory morphological changes during development but presented signs of regeneration along the first days of life

Orientador: Rosilene Fernandes da Rocha / Banca: Maria Rozeli de Souza Quirino / Banca: Carmelinda Schmidt Unterkircher / Resumo: O objetivo deste estudo foi avaliar a influência da tetraciclina administrada a ratas prenhas no desenvolvimento hepático e renal de filhotes. Foram utilizadas quinze ratas sendo três controles e 12 tratadas. As ratas controle receberam injeções de solução fisiológica, enquanto as dos grupos experimentais foram tratadas com cloridrato de tetraciclina nas doses de 25, 50, 75 e 100mg/kg, via intraperitoneal, em dose única, no décimo dia da gestação. Os filhotes foram sacrificados ao nascer, com dez, vinte e trinta dias de vida. A análise histológica do fígado mostrou vacuolização, necrose, inflamação e dilatação sinusoidal principalmente em recém-nascidos. Mitoses, aumento precoce da população de células de Kupffer, hipertrofia de hepatócitos com maior síntese de glicogênio foram mais acentuadas nos filhotes com dez e vinte dias. No rim verificamos vacuolização tubular e necrose discretas, que ficaram mais evidentes nos recém-nascidos, e sinais de regeneração tubular aos dez e vinte dias. Os resultados sugerem que os órgãos estudados sofreram alterações morfológicas transitórias durante o desenvolvimento, mas revelaram indícios de regeneração ao longo do tempo / Abstract: This study aims to evaluate the possible effects of tetracycline administered to pregnant rats on kidney and liver development of their offspring. Fifteen rats were used - three controls and twelve treated ones. The control group received saline injections while the experimental groups were administered tetracycline chlorhidrate in the doses of 25, 50, 75 and 100mglkg, intraperitoneally, in a single injection, on the tenth day of pregnancy. The sucking were sacrificed at birth and after ten, twenty and thirty days of life. The liver specimes showed vacuolizations, necrosis, inflammation and sinusoidal dilatations, more evident in the newborn. Mitosis, early increase of Kupffer cells population and hypertrophy of hepatocytes with greater synthesis of glycogen were present in the 10th and twentieth days of life. The kidney specimens showed slight tubular vacuolizations and necrosis, more prominent in the newbom, as well as signs of tubular regeneration at the tenth and twentieth days. These results suggest that the organs studied went through several transitory morphological changes during development but presented signs of regeneration along the first days of life / Mestre

<p> The most uncommon form of tetracycline resistance is enzymatic inactivation of the drug. The first protein characterized that was shown to have this ability was TetX, a 44-kDa cytoplasmic protein responsible for inactivating tetracycline in E. coli. The associated gene, tetX, was found on a transposon in the bacterium Bacteroides fragilis, and encodes an NADP-requiring, FAD-dependent monooxygenase. TetX modifies the structure of tetracycline by the addition of a hydroxyl to the C-11a position, altering the β-diketone system of the tetracycline that is responsible for antibiotic activity. This project was designed to search for novel tetracycline inactivators, and to determine the origin of the tetX. Initially, the search for TetX-like proteins in S. coelicolor and C. hutchinsonii was performed using homologous protein sequences found using BLAST searches. Each of the genes encoding the homologous protein sequences was cloned, over-expressed and purified, then analyzed using HPLC and LC/MS methods to determine their tetracycline inactivating ability. Next, the published tetracycline inactivators Tet34 and Tet37 were tested for their ability to inactivate the drug using HPLC and LC/MS methods, after being cloned, over-expressed and purified. Finally, a search of the Actinomycete library belonging to the Wright Laboratory was conducted looking for novel tetracycline inactivators. Bioassays were the first step in a series of experiments done, with HPLC and LC/MS assays eventually being used to determine if an inactivation event was occurring. The homologous sequences from S. coelicolor and C. hutchinsonii did not inactivate tetracycline as determined by HPLC and LC/MS data. The potential inactivators, Tet34 and Tet37, were also found to be void of tetracycline inactivating activity. Finally, one isolate in the actinomycete library was thought to be inactivating the drug, however, upon further inspection via HPLC and LC/MS methods this inactivation event was dismissed. Future research should focus on the search for novel enzymes capable of modifying the structure of tetracycline, as well as the origin of the only known tetracycline inactivator, tetX.</p> / Thesis / Master of Science (MSc)

This research project deals with the characterization of self-replicating Kirsten murine viral DNA. The replication of this viral DNA and tetracycline resistance conferred to bacteria by this viral DNA will be studied. The restriction endonuclease and Southern blot analysis revealed a fragment of pBR322 from the Hind III and Pst I site that is located in the 3' end of the MLV-K:E molecule. Single stranded sequencing of the two terminal ends of this fragment verified that the 3' end of MLV-K:E contains identical sequence homology to pBR322. The presence of this pBR322 fragment explains the unusual properties of the MLV-K:E molecule. However, tetracycline resistance is less in E. Coli containing MLV-K:E than E. coli containing pBR322 as determined by zone of inhibition assay. This may be due to alteration in the promoter region of the tetracycline gene.

No description available.

No description available.

The purpose of this study was to compare the antimicrobial effect of MTAD, two of its components, doxycycline and citric acid, and NaOCl on E. faecalis in two in vitro models: the bovine tooth model and the agar diffusion model. In the tooth model, the lumens of thirty bovine dentin discs were standardized, autoclaved and infected with E. faecalis for 14 days. The infected dentin discs were treated with either MTAD, doxycycline 100mg/ml, 10% citric acid, 5.25% NaOCl or saline for 10 minutes. Dentinal shavings were collected using sterile 037 and 040 round burs. The number of bacteria in the shavings was enumerated by overnight CO2 culturing on TSA agar plates. For the agar diffusion model, E. faecalis was plated before placing paper discs wetted with three dilutions of each irrigant. The zone of inhibition was recorded after overnight culture. The data were analyzed with a two-way ANOVA and Tukey-Kramer post-hoc test. In the bovine tooth model, NaOCl and doxycycline were more effective than control in killing E. faecalis at the shallow bur depth but at the deeper bur depth, only NaOCl was significantly more effective (psE. faecalis.

Neste trabalho desenvolveu-se um sensor eletroquímico a partir da modificação de superfície de um eletrodo de carbono vítreo com nanopartículas metálicas de Pt e intermetálicas de NiSb suportadas em carbono Vulcan&reg; XC72. Tal modificação visou à obtenção de um sensor de baixo custo, simples e rápido para determinação do cloridrato de tetraciclina (TTC). A tetraciclina é um fármaco com propriedades antibióticas amplamente utilizado na saúde humana e animal devido sua baixa toxicidade e fácil obtenção. A modificação de superfície do eletrodo de trabalho foi realizada a partir da adição de uma suspensão das nanopartículas em dimetilformamida (DMF) (1 mg/1 mL) sobre a superfície do eletrodo previamente limpo e os estudos voltamétricos conduzidos utilizando as técnicas de voltametria cíclica, voltametria de pulso diferencial e cronoamperometria. Como consequência dos resultados obtidos, prosseguiu-se apenas com os estudos da nanopartícula de Pt na construção de um sensor para determinação da TTC. As nanopartículas apresentam propriedades diferentes daquelas exibidas pelo mesmo material quando estes se encontram em partículas de maior tamanho como bulks, e dentre suas principais características, o aumento da área superficial provocado pela modificação do eletrodo mostrou resultados promissores na detecção e quantificação do analito. Após diversos estudos sobre o eletrólito de suporte e o pH, obteve-se a melhor resposta voltamétrica em solução de tampão fosfato 0,10 mol L-1 pH 3,0 através da voltametria cíclica tanto na determinação do analito em água purificada quanto na determinação em urina sintética. O eletrodo modificado com nanopartículas de Pt apresentou resposta linear na faixa de 9,99 e 44,01 &micro;mol L-1, limite de detecção 4,28 &micro;mol L-1 e limite de quantificação 14,26 &micro;mol L-1. A aplicação do eletrodo em uma amostra de urina sintética ocorreu com sucesso, alcançando um valor de concentração com diferença de 3% para o valor real. / In this work it was developed an electrochemical sensor by the surface modification of a glassy carbon electrode with metallic Pt nanoparticles and intermetallic NiSb nanoparticles in Vulcan&reg; XC72 carbon as the support. Such surface modification sought to obtain a low cost sensor, easy to work and quick working to determine tetracycline hydrochloride. The tetracycline is a drug with antibiotics properties widely used in human and animal treatment due to its low toxicity and easy obtainability. The surface modification of the work electrode was accomplished through the addition of a suspension of the nanoparticles in dimethylformamide (1 mg/1 mL) in the electrode surface previously cleaned and the voltammetric studies conducted with the use of techniques such as cyclic voltammetry, differential pulse voltammetry and chronoamperometry. As a consequence of the obtained results, only the studies with the sensor developed with Pt nanoparticles were continued for the tetracycline determination. The nanoparticles presents different properties of those shown by the same material when these are in bigger forms, such as bulks and among the main characteristic, the superficial area increase caused by the electrode modification shown promising results for the detection and quantification of the analyte. After several studies about the supporting electrolyte and the pH, it was obtained a better voltammetric response in phosphate buffer solution 0.1 mol L-1 and pH 3.0 for the determination of the analyte in purified water and synthetic urine. The modified electrode with metallic Pt nanoparticles had a linear response in the range 9.99 to 44.01 &micro;mol L-1 with a detection limit of 4.28 &micro;mol L-1 and quantification limit of 14.26 &micro;mol L-1. The electrode application in a synthetic urine sample was a success, reaching concentration values with a difference within 3% of the real value.