Dada a existência de quatro famílias molecularmente distintas de estirpes de Mycobacterium avium isoladas de suínos da região Sul do Brasil e a verificação de diferentes virulências em hamsters de um representante por família, o presente trabalho objetiva relacionar a virulência de isolados de M. avium aos seus perfis genéticos obtidos em experimentos de RFLP. Foram selecionados três representantes por família que foram inoculados pela via intraperitoneal em hamsters distribuídos em doze grupos (cada grupo recebeu uma estirpe diferente). Foi mantido um grupo controle que recebeu solução salina estéril pela mesma via. Após 16 dias da inoculação, os animais foram eutanasiados; os baços foram colhidos, pesados, macerados, suspendidos em solução salina estéril e diluídos. Cada uma das diluições foi semeada em duplicata em placas com meio de Petragnani, que foram incubadas a 37°C. Após 30 dias de incubação, foram realizadas as contagens de UFC e os resultados foram expressos em UFC de M. avium por grama de baço. As famílias genéticas apresentaram capacidade de virulência semelhante (p=0,49). As estirpes dentro das famílias PIG B e PIG D não apresentaram diferença na virulência (p=0,15 e p=0,87, respectivamente). Dentro da família PIG A, o isolado A52 foi mais virulento do que A1 e A162; a estirpe C122 se apresentou menos virulenta do que as estirpes C44 e C68 dentro da família PIG C. Independente das famílias, todos os isolados apresentaram diferenças na virulência. A estirpe A52 mostrou maior capacidade de virulência em relação às estirpes A1, A162, B72, C122, D242 e 243. Diferentes contagens de UFC significam diferentes capacidades de produzir infecção, ou seja, diferentes virulências. Concluiu-se que isolados de M. avium com diferentes perfis de RFLP podem apresentar diferentes virulências, independentemente de pertencerem a uma mesma família genética definida com base na similaridade dos padrões de RFLP; não houve diferença de virulência entre as quatro famílias genéticas de M. avium estruturadas com base na similaridade dos padrões de RFLP. / Knowing the existence of four molecularly distinct families of Mycobacterium avium strains isolated from swine populations of Brazil Southern and the corroboration of diverse virulence in experimentally infected hamsters by one representative of each family, this work intend to establish relation between virulence of M. avium isolates and their genetic patterns obtained in prior RFLP analyses. We selected three representatives of each family, totalizing twelve strains, which were introduced by intraperitoneal route into hamsters distributed in twelve groups (each group received a different strain). A control group was maintained and received buffer solution by the same route. Sixteen days after the inoculation, animals were euthanized and their spleens were collected, weighted, triturated, suspended in buffer solution and then diluted. Two plates containing Petragnani medium were seeded with each dilution and were incubated at 37ºC. At the 30th day, the CFU counting was performed and the results were expressed in M. avium CFU/g of spleen. All genetic families presented similar capacity of virulence (p=0,49). Strains of PIG B and PIG D families presented similar virulence within their families (respectively, p=0,15 and p=0,87). Inside the PIG A family, strain A52 was more virulent than strains A1 and A162; the strain C122 presented the lowest virulence compared with the strains C44 and C68 within the PIG C family. All strains, independent of their family, presented diverse virulence. Strain A52 was more virulent than strains A1, A162, B72, C122, D242 and D243. Distinct counting of CFU means different capacity of producing infection, i.e. diverse virulence. We concluded that, independent fo the genetic family established by similarity of RFLP patterns, M. avium isolates with diverse RFLP profiles may present different virulence; there was not difference in virulence; among all of four M. avium genetic families structured according to the similarity of RFLP patterns.

A doença de Chagas ainda permanece como um importante problema de saúde em regiões endêmicas na América Latina, onde se estima 8 a 10 milhões de infectados. A isquemia microvascular é frequente na cardiomiopatia chagásica crônica (CCC) e pode estar envolvida nos processos fisiopatogênicos que levam à disfunção sistólica ventricular esquerda (DSVE). Lança-se a hipótese que a redução da isquemia microvascular possa atenuar a progressão da DSVE na CCC. Desta forma, nosso objetivo foi avaliar os efeitos do uso prolongado do dipiridamol (DIPI), um agente vasodilatador da microcirculação coronária, sobre a perfusão miocárdica e sobre a função sistólica do ventrículo esquerdo mediante emprego de métodos de imagem in vivo. Foram utilizados 60 hamsters fêmeas adultas divididas em: animais infectados com T. cruzi e tratados com DIPI (Chagas + DIPI, n=15); infectados tratados com placebo (Chagas + Placebo, n=15); animais não infectados, tratados com DIPI (Controle + DIPI, n=15) e tratados com placebo (Controle + placebo, n=15). Após 6 meses de infecção (condição basal), os animais foram submetidos a ecocardiograma e a cintilografia de perfusão miocárdica por SPECT com Sestamibi-Tc99m. Em seguida, foram tratados com injeções intraperitoneais de DIPI (4mg/Kg) duas vezes ao dia ou igual volume de salina, durante 30 dias. Após o tratamento, os animais foram reavaliados com os mesmos métodos de imagem e a seguir sofreram eutanásia e o tecido cardíaco foi preparado para análise histológica quantitativa para extensão de fibrose (coloração de picrosírius vermelho) e do infiltrado inflamatório (coloração de hematoxilinaeosina). Na condição basal os animais do grupo Chagas + placebo e Chagas + DIPI apresentaram maior área de defeito de perfusão (19,2 ± 5,4% e 20,9 ± 4,2%, respectivamente, quando comparados aos grupos controle + placebo e controle + DIPI (3,8 ± 0,7% e 3,6 ± 0,9%, respectivamente), p=0<0,05, mas valores semelhantes de fração de ejeção do ventrículo esquerdo (FEVE), p=0,3, e de diâmetro diastólico do ventrículo esquerdo (DdVE,), p=0,2. Após o tratamento, observou-se redução significativa dos defeitos de perfusão somente no grupo Chagas + DIPI (p=0,02). Quando comparados os valores basais e após tratamento, os animais dos grupos Chagas + DIPI e Chagas + placebo apresentaram redução da FEVE (65,3 ± 2,5% para 53,6 ± 1,9% e 69,3 ± 1,4% para 54,4 ± 2,5%, respectivamente (p<0,001), e aumento do DdVE de 0,68 ± 0,5 cm para 0,76 ±0,17 cm e 0,64 ± 0,01 cm para 0,71 ± 0,23 cm, respectivamente (p<0,002). Na análise histológica quantitativa, observou-se maior número de núcleos de células inflamatórias mononucleares nos grupos Chagas + DIPI (998,1 ± 116,0 cel/mm²) e Chagas + Placebo (1191,4 ± 133,2 cel/mm²) quando comparados aos grupos Controle + DIPI (396,5 ± 28,3 cel/mm²) e Controle + Placebo (257,1 ± 21,6 cel/mm²), p=0,05. A porcentagem de fibrose foi maior nos grupos Chagas + DIPI (4,7 ± 0,4%) e Chagas + Placebo (5,4 ± 0,2%) quando comparados com o grupo controle + Placebo (3,2 ± 0,3%). Não houve diferença entre os grupos Chagas + DIPI e Chagas + Placebo em ambas as variáveis da histologia. Conclusões: O uso prolongado de DIPI em animais com CCC associou-se à significativa redução dos defeitos de perfusão miocárdica avaliados in vivo. Contudo, a resolução da isquemia microvascular mediante emprego de DIPI não impediu a progressão da disfunção ventricular esquerda. Esses resultados sugerem que a isquemia microvascular não seja um mecanismo lesivo miocárdico central no complexo fisiopatogênico neste modelo de CCC. É plausível supor que a isquemia microvascular seja um marcador da presença de processo lesivo subjacente, provavelmente de natureza inflamatória. / Chagas disease continues to be an important public health problem in endemic regions of Latin America, where 8 to 10 million infected people are estimated to live. Microvascular ischemia is frequent in chronic chagasic cardiomyopathy (CCC) and may be involved in the physiopathogenic processes that lead to left ventricular systolic dysfunction (LVSD). The hypothesis is raised that reduction of microvascular ischemia may attenuate the progression of LVSD in CCC. Thus, our objective was to assess the effects of prolonged use of dipyridamole (DIPY), a coronary microvascular dilator agent, on myocardial perfusion and on left ventricular systolic function using imaging methods in vivo. A total of 60 adult female hamsters were divided into the following groups: T. cruzi-infected animals treated with DIPY (Chagas + DIPY, n=15); infected animals treated with placebo (Chagas + Placebo, n=15); uninfected animals treated with DIPY (Control + DIPY, n=15) and treated with placebo (Control + placebo, n=15). After 6 months of infection (baseline condition), the animals were submitted to an echocardiogram and to rest myocardial perfusion scintigraphy by SPECT with SestamibiTc99m. Next, the animals were treated with intraperitoneal injections of DIPY (4 mg/kg) twice a day or with an equal volume of saline for 30 days. After treatment, the animals were reevaluated by the same imaging methods and euthanized. Cardiac tissue was prepared for quantitative histological analysis of the extent of fibrosis (picrosirius red staining) and of the inflammatory infiltrate (hematoxylin-eosin staining). At baseline, the group Chagas + placebo and Chagas + DIPY showed a larger area of perfusion defect (19.2 ± 5.4% and 20.9 ± 4.2%, respectively) compared to control + placebo and control + DIPY (3.8 ± 0.7% e 3.6 ± 0.9%, respectively), p<0.05, but similar left ventricular ejection fraction (LVEF), p=0.3, and left ventricular diastolic diameter (LVdD), p=0.2. After treatment, a significant reduction of perfusion defects was observed only in the Chagas + DIPY group (p=0.02). When the values after treatment were compared to baseline values, Chagas + DIPY and Chagas + placebo animals showed a reduction of LVEF (from 65.3 ± 2.5% to 53.6 ± 1.9% and from 69.3 ± 1.4% to 54.4 ± 2.%5, respectively), p<0.001, and an increase of LVdD from 0.68 ± 0,15 cm to 0.76 ± 0.17 cm and from 0.64 ± 0.01 cm to 0.70 ± 0,02 cm, respectively, p<0.002. Quantitative histological analysis revealed a larger number of nuclei of mononuclear inflammatory cells in the Chagas + DIPY (998.1 ± 116.0 cel/mm²) and Chagas + Placebo (1191.4 ± 133.2 cells/mm²) groups compared to the Control + DIPY (396.5 ± 28.3 cells/mm²) and Control + Placebo (257.1 ± 21.6 cells/mm²) groups, p=0.05. The percentage of fibrosis was higher in the Chagas + DIPY (4.7 ± 0.4%) and Chagas + Placebo (5.4 ± 0.2%) groups compared to the Control + Placebo group (3.2 ± 0.3%). There was no difference between the Chagas + DIPY and Chagas + Placebo groups regarding the two histological variables. Conclusions: The prolonged use of DIPY in animals with CCC was associated with a significant reduction of myocardial perfusion defects assessed in vivo. However, the resolution of microvascular ischemia with the use of DIPY did not prevent the progression of left ventricular dysfunction. These results suggest that microvascular ischemia may not be a central myocardial injury mechanism in the physiopathogenic complex of this CCC model. It is plausible to assume that microvascular ischemia may be a marker of the presence of an underlying injury process probably of an inflammatory nature.

Thesis: M.S., Massachusetts Institute of Technology, Department of Psychology, 1973 / Vita. / Bibliography: leaves 67-73. / M.S. / M.S. Massachusetts Institute of Technology, Department of Psychology

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

Tan, Sijiao. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 118-136). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (in English) --- p.iii / Abstract (in Chinese) --- p.vi / List of Abbreviations --- p.viii / Table of Contents --- p.x / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Frying --- p.1 / Chapter 1.1.1 --- General introduction of frying --- p.1 / Chapter 1.1.2 --- Physical and chemical changes of oils during frying --- p.2 / Chapter 1.1.2.1 --- Physical changes --- p.2 / Chapter 1.1.2.2 --- Chemical changes --- p.5 / Chapter 1.1.2.2.1 --- Hydrolysis --- p.5 / Chapter 1.1.2.2.2 --- Oxidation --- p.5 / Chapter 1.1.2.2.3 --- Polymerization --- p.6 / Chapter 1.1.3 --- Frying oil selection --- p.11 / Chapter 1.1.4 --- Quality control of frying oil --- p.11 / Chapter 1.2 --- Selection of experiment oil --- p.13 / Chapter 1.2.1 --- Lard as a cholesterol-containing animal fat --- p.13 / Chapter 1.2.2 --- Corn oil as a healthy vegetable oil --- p.14 / Chapter 1.3 --- Current studies on frying oils --- p.18 / Chapter 1.4 --- Atherosclerosis and cholesterol metabolism --- p.19 / Chapter 1.4.1 --- Atherosclerosis --- p.19 / Chapter 1.4.2 --- Cholesterol metabolism and related regulating factor --- p.23 / Chapter 1.5 --- Animal model selection --- p.29 / Chapter CHAPTER 2 --- OBEJECTIVES --- p.30 / Chapter CHAPTER 3 --- MATERIALS AND METHODS / Chapter 3.1 --- Sample lard and corn oil preparation --- p.31 / Chapter 3.2 --- Diet preparation --- p.34 / Chapter 3.3 --- Animals --- p.36 / Chapter 3.4 --- Sample collection --- p.36 / Chapter 3.5 --- GC analysis of fatty acid composition in fresh and fried experiment oil samples --- p.37 / Chapter 3.6 --- Determination of plasma cholesterol and organ cholesterol --- p.41 / Chapter 3.7 --- "Determination of hamster fecal neutral and acidic sterols, corn oil phytosterol content" --- p.44 / Chapter 3.7.1 --- Determination of fecal neutral sterols --- p.44 / Chapter 3.7.2 --- Determination of fecal acidic sterols --- p.45 / Chapter 3.7.3 --- Determination of phytosterol content in corn oil --- p.46 / Chapter 3.8 --- "Determination of composition and concentration of liver triglycerides, total free fatty acids and phospholipids" --- p.51 / Chapter 3.9 --- Statistics --- p.54 / Chapter CHAPTER 4 --- RESULTS IN FRIED LARD EXPERIMENT / Chapter 4.1 --- Fatty acid composition and cholesterol content of experiment lard --- p.55 / Chapter 4.2 --- Body weight and food intake --- p.55 / Chapter 4.3 --- Relative organ weight --- p.55 / Chapter 4.4 --- "Plasma total cholesterol, triglycerides and HDL- cholesterol" --- p.60 / Chapter 4.5 --- Organ cholesterol --- p.60 / Chapter 4.6 --- Fecal neutral sterol output --- p.64 / Chapter 4.7 --- Fecal acidic sterol output --- p.64 / Chapter 4.8 --- Effect of fried lard on cholesterol balance in hamster --- p.64 / Chapter 4.9 --- "Effect of fried lard on hepatic triglycerides, free fatty acids and phospholipids concentration in hamster" --- p.68 / Chapter 4.10 --- Correlation between serum HDL cholesterol and liver cholesterol --- p.76 / Chapter 4.11 --- Correlation between serum HDL cholesterol and kidney cholesterol --- p.76 / Chapter 4.12 --- Correlation between serum TG and liver TG --- p.76 / Chapter CHAPTER 5 --- RESULTS OF FRIED CORN OIL EXPERIMENT / Chapter 5.1 --- Fatty acid composition and phytosterol content of experiment corn oil --- p.80 / Chapter 5.2 --- Body weight and food intake --- p.80 / Chapter 5.3 --- Relative organ weight --- p.84 / Chapter 5.4 --- Plasma total cholesterol，triglycerides and HDL- cholesterol --- p.84 / Chapter 5.5 --- Organ cholesterol --- p.87 / Chapter 5.6 --- Fecal neutral sterol and phytosterol output --- p.87 / Chapter 5.7 --- Fecal acidic sterol output --- p.92 / Chapter 5.8 --- Effect of fried corn oil on cholesterol balance and phytosterol balance in hamsters --- p.92 / Chapter 5.9 --- "Effect of fried corn oil on hepatic triglycerides, free fatty acids and phospholipids concentration in hamster" --- p.97 / Chapter 5.10 --- Correlation between serum HDL cholesterol and liver cholesterol --- p.105 / Chapter 5.11 --- Correlation between serum HDL cholesterol and kidney cholesterol --- p.105 / Chapter 5.12 --- Correlation between serum TG and liver TG --- p.105 / Chapter CHAPTER 6 --- DISCUSSION --- p.109 / Chapter CHAPTER 7 --- CONCLUSION --- p.117 / REFERENCE --- p.118

published_or_final_version / Medicine / Master / Doctor of Medicine

published_or_final_version / abstract / toc / Molecular Biology / Master / Master of Philosophy

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy