• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 297
  • 41
  • 24
  • 19
  • 16
  • 14
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 563
  • 126
  • 103
  • 91
  • 57
  • 55
  • 55
  • 50
  • 48
  • 46
  • 46
  • 44
  • 41
  • 41
  • 41
  • 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.
451

Uticaj soli žučnih kiselina na prodor i metabolizam simvastatina u probiotskim bakterijama / The influence of bile salts on simvastatin transport and metabolism in probiotic bacteria

Đanić Maja 15 September 2016 (has links)
<p>Interindividualne razlike u sastavu i aktivnosti crevne mikroflore mogu uticati na metabolizam lekova kao i na njihov konačan terapijski odgovor. Simvastatin je lek iz grupe statina i karakteri&scaron;e ga izuzetno mala rastvorljivost u vodi, mala bioraspoloživost (&lt;5%) i velike interindividualne razlike u terapijskom odgovoru čiji uzroci nisu u potpunosti obja&scaron;njeni. Poslednjih godina velika pažnja se posvećuje ispitivanjima žučnih kiselina u razvoju novih farmaceutskih formulacija zbog svoje uloge u solubilizaciji i modifikaciji prodora lekova kroz biolo&scaron;ke membrane. Zbog svega navedenog, u fokusu na&scaron;eg istraživanja su bile potencijalne interakcije između simvastatina, probiotskih bakterija i žučnih kiselina o kojima se vrlo malo zna, a od izuzetne su važnosti, zbog mogućeg uticaja na farmakokinetske i farmakodinamske osobine simvastatina, pa samim tim i na konačan terapijski odgovor kod pacijenta.Cilj istraživanja je bio da se ispita prodor i metabolizam simvastatina u probiotskim bakterijama kao i uticaj različitih žučnih kiselina na transport ovog leka u bakterijske ćelije. Takođe, cilj je bio da se ispita uticaj soli žučnih kiselina na distribucioni koeficijent simvastatina, kao i interakcije žučnih kiselina sa simvastatinom na nivou transportnih proteina probiotskih bakterija kako bi se objasnila priroda očekivanih interakcija.Identifikacija i kvantifikacija uzoraka vr&scaron;ena je metodom tečne hromatografije sa masenom spektrometrijom (LC-MS/MS). Kori&scaron;ćenjem programskih paketa VolSurf+ i Molinspiration, za identifikovane metabolite su izračunati molekulski deskriptori koji opisuju fizičko-hemijske i farmakokinetske osobine molekula. Određivanje distribucionog koeficijenta vr&scaron;eno je Shake-flask metodom. Interakcije žučnih kiselina sa simvastatinom na nivou transportnih proteina probiotskih bakterija ispitane su doking studijama pomoću SwissDock programa. Prilikom dvadesetčetvoročasovne inkubacije sa probiotskim bakterijama uočen je statistički značajan pad koncentracije simvastatina u ekstracelularnom sadržaju. Ukupan sadržaj simvastatina, kao zbir ekstracelulamog i intracelularnog sadržaja, je tokom čitavog ispitivanog perioda bio statistički značajno niži u odnosu na kontrolnu grupu bez probiotika navodeći na zaključak da se deo simvastatina tokom vremena metabolisao pod dejstvom enzima ispitivanih bakterija. Detektovano je i identifikovano 8 metaboličkih produkata simvastatina. Na osnovu izračunatih vrednosti molekulskih deskriptora, očekuje se da će metabolit M-452, koji predstavlja hidroksilovani produkt simvastatinske kiseline, pokazati najbolje rezultate u pogledu fizičko-hemijskih osobina i bioraspoloživosti u biolo&scaron;kom sistemu. Žučne kiseline nisu dovele do statistički značajne modifikacije transporta simvastatina u/iz probiotskih bakterija. Ipak, u nekim vremenskim tačkama primećena je ne&scaron;to veća koncentracija leka u ekstracelulamom prostoru u grupama sa žučnim kiselinama. Ove razlike se mogu delimično objasniti rezultatima određivanja distribucionog koeficijenta koji su pokazali da ispitivane žučne kiseline dovode do statistički značajnog smanjenja distribucionog koeficijenta simvastatina usled povećanja rastvorljivosti u vodenoj fazi. Rezultatima doking studija procenjeno je da ispitivane žučne kiseline imaju veći afinitet prema čak 80% multidrug transportera ispitivanih bakterija u odnosu na simvastatin &scaron;to govori o mogućnosti ostvarivanja interakcija žučnih kiselina sa ovim lekom na nivou transportnih proteina probiotskih bakterija. Na osnovu dobijenih rezultata možemo zaključiti da probiotske bakterije imaju ogroman uticaj na sudbinu simvastatina u biolo&scaron;kom sistemu. Uzimajući u obzir činjenicu da probiotske bakterije ulaze u sastav normalne crevne flore i da svaki organizam poseduje specifičan bakterijski sastav, trebalo bi posvetiti vi&scaron;e pažnje ispitivanju njegovog uticaja na farmakokinetiku lekova. Neophodna su dalja in vivo ispitivanja kako bi se utvrdila potencijalna farmakolo&scaron;ka aktivnost identifikovanih metabolita simvastatina nastalih pod dejstvom enzimske aktivnosti probiotskih bakterija. Povećanje rastvorljivosti simvastatina pomoću žučnih kiselina otvara mogućnost za dalja istraživanja u cilju razvoja novih farmaceutskih formulacija sa pobolj&scaron;anom bioraspoloživosti i farmakokinetskim osobinama.</p> / <p>Interindividual differences in the composition and activity of the gut microflora may affect the metabolism of drugs as well as their final therapeutic response. Simvastatin is drug from the group of statins and has extremely low water solubility, low bioavailability (&lt;5%) and high interindividual differences in therapeutic response whose causes are not fully understood. In recent years, great attention has been paid to studies of bile acids in the development of new pharmaceutical formulations because of their role in the drug solubilization and modification of drug transport through biological membranes. Accordingly, interactions between simvastatin, probiotic bacteria and bile acids were the focus of our research due to great importance and potential influence on the pharmacokinetic and pharmacodynamic properties of simvastatin, and therefore the final therapeutic response in the patients. The aim of the study was to investigate the simvastatin transport and metabolism in probiotic bacteria as well as the effect of various bile acids on drug transport into the bacterial cell. Additonally, the aim was to investigate the influence of bile salts on the distribution coefficient of simvastatin, and the interactions of bile acids with simvastatin at the level of probiotic transport proteins in order to elucidate the nature of expected interactions. Identification and quantification of samples were performed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Molecular descriptors that describe the physico-chemical and pharmacokinetic properties of identified metabolites were calculated using the software packages VolSurf+ and Molinspiration. Determination of the distribution coefficient was performed using Shake-flask method. Interaction of bile acids with simvastatin at the level of bacterial transport proteins were studied using docking studies with SwissDock program. During the twenty-four hours of incubation with probiotic bacteria, simvastatin concentrations in the extracellular contet showed a statistically significant decrease. The total amount of simvastatin, as the sum of the extracellular and intracellular amount, during the whole study period, was significantly lower in comparison with control group without probiotics, suggesting that the part of simvastatin was metabolized by the enzymatic activity of studied bacteria. Accordingly, eight metabolic products of simvastatin were detected and identified. Based on the calculated values of molecular descriptors, it is expected that the metabolite M-452, which is the hydroxylated product of simvastatin acid, will show the best results in terms of physico-chemical properties and bioavailability in biological system. Bile acids did not show a significant influence on simvastatin transport into probiotic bacteria. However, in some time points, slightly higher drug concentrations in the extracellular medium in groups with bile acids were observed. These differences can be partly explained by the results of the determination of the distribution coefficients which showed that investigated bile acids lead to a statistically significant decrease in simvastatin distribution coefficient due to increased solubility in the aqueous phase. The results of docking studies estimated that studied bile acids have stronger affinities for the 80% of bacterial multidrug transporters compared to simvastatin indicating the possibility of achieving the interactions of bile acids with simvastatin at the level of transport proteins of probiotic bacteria. Based on the obtained results it could be concluded that probiotic bacteria have great influence on the fate of simvastatin in a biological system. Taking into account the fact that probiotic bacteria are the normal part of gut microflora and that each individual has specific bacterial fingerprint, more attention should be paid on studying its influence on drug pharmakocinetics. Further in vivo studies are required in order to determine potential pharmacological activity of identified simvastatin metabolites. Increased water solubility of simvastatin with bile acids may open the possibility for further investigations with the aim of development of new pharmaceutical formulation with improved bioavailability and pharmacokinetic properties.</p>
452

Střevní mikrobiota a poruchy nálady / Intestinal microbiota and mood disorders

Ambrožová, Lucie January 2016 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Candidate: Lucie Ambrožová Supervisor: Doc. MUDr. Josef Herink, DrSc. Title of diploma thesis: Intestinal microbiota and mood disorders The intestinal microbiom is composed mainly of two dominated strains - Bacteroidetes and Firmicutes. The other strains are just not numerous like the previous ones. The specimens have the invariable core of microbiom which doesn't change in time. Nevertheless they have also the transient gut bacteria, which change during their life. Intestinal microbiom is influenced by many factors. Between them we can categorize for example the way of the childbirth, the breast - feeding, the alimentation, the state of health, and the medicaments. Every specimen has own specific microbiom. It was found that human population is possible to divide into three intestinal groups or enterotypes. To each enterotype dominates different bacterial strain. It was proved that intestinal microbiom communicates with the brain and it works also vice versa. This communication system is called "brain - intestine" and takes several ways in several body systems (such as nervous, endocrine, metabolic, and immune). To normal development of the brain is needed the right colonisation of non...
453

Úloha střevního mikrobiomu v imunitních onemocněních centrálního nervového systému / The role of the gut microbiome in immune-mediated CNS disorders

Zedníková, Barbora January 2016 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Candidate: Bc. Barbora Zedníková Supervisor: Doc. MUDr. Josef Herink, DrSc. Title of diploma thesis: The role of the gut microbiome in immune-mediated CNS disorders Human body hosts a large number of microorganisms - i.e. Archea, Eukarya, Bacteria and viruses. These microorganisms form microbiome, the total number of the microorganisms is ten times higher than the number of all human cells. Largest part of the microbiome is located in the intestine. The current development of molecular genetics revealed the close relationship between intestinal microbiome and health. Recent studies the most recent studies have pointed to a connection with the pathogenesis of various diseases. This dissertation is focused on the connection between intestinal microbiome and autoimmune diseases of the central nervous system. Research shows that the key factor are the ongoing changes in the composition of microbiome. These changes lead to increased immune stimulation and thereby to inflammatory proliferation.
454

The spittlebug Mahanarva fimbriolata (St&#229;l) produces foam as a thermoregulatory and defensive strategy / A cigarrinha Mahanarva fimbriolata (St&#229;l) produz espuma como estratégia termorregulatória e defensiva

Tonelli, Mateus 16 April 2019 (has links)
Insects of the family Cercopidae are easily identified by the spit-like foam that they produce to surround themselves during the nymphal stage. Known as spittlebugs, these insects can be observed developing in a wide range of host plants. Among the functions attributed to the foam, there are the protection of nymphs against high temperatures, desiccation and natural enemies. However, experimental evidence to confirm these hypotheses are sparse. Mahanarva fimbriolata is an economically important spittlebug in Brazilian sugarcane crops, especially after the harvest with burning had been prohibited. The nymphs of M. fimbriolata develop on the soil surface or below ground where they suck the xylem content of exposed sugarcane roots, blocking the water and nutrients transport, eventually causing physiological disorder. In this thesis, it was evaluated the importance of foam for the thermoregulation of M. fimbriolata nymphs, its bacterial microbiome and the protective action against predators. The thesis was divided into four chapters. The Chapter 1 presented an introduction to the bioecological aspects of M. fimbriolata and the possible role of foam produced by the nymphs, which was explored in details along the other chapters. The Chapter 2 examined the importance of foam and its chemical compounds in the thermoregulation of nymphs. The Chapter 3 explored the diversity and composition of bacterial community present in the foam, in the gut of nymphs, and in the soil close to the foam. The Chapter 4 investigated whether the foam acts in protecting the nymphs against the predatory ants Solenopsis invicta, and its topical irritancy to the cockroaches Periplaneta americana. It was demonstrated that the foam produced by M. fimbriolata: (i) serves as an important thermal microhabitat, maintaining the temperature close to the ideal for the nymphs development; (ii) harbor a diversity of bacteria previously reported as protective symbionts of insects, which are probably originated from the nymphs\'s gut; and (iii) is a repellent to predators and topical irritant to another arthropod (roaches). Taken together, the foam produced by M. fimbriolata is a thermoregulatory and defensive strategy to the nymphs. In addition, this thesis serves as a background for future research that aims to investigate the importance of foam for the growth and development of spittlebugs. / Os insetos da família Cercopidae são facilmente reconhecidos pela espuma que produzem durante o desenvolvimento ninfal para recobrir o próprio corpo. Essas ninfas, conhecidas como cigarrinhas, podem ser observadas em uma ampla gama de plantas hospedeiras. Dentre as funções atribuídas à espuma estão a proteção contra elevadas temperaturas, dessecação e inimigos naturais. Contudo, evidências experimentais para confirmar estas hipóteses são escassas. Mahanarva fimbriolata é uma cigarrinha de importância econômica em áreas de produção de cana-de-açúcar no Brasil, especialmente após a proibição da colheita da cana com queima prévia. As ninfas de M. fimbriolata se desenvolvem nas raízes de cana-de-açúcar expostas na superfície ou abaixo do solo, onde sugam a seiva do xilema, bloqueando o transporte de água e nutrientes e causando desordens fisiológicas. Nesta tese foi avaliada a importância da espuma para a termorregulação de ninfas de M. fimbriolata, seu microbioma bacteriano e sua ação protetora contra predadores. A tese foi dividida em quatro capítulos. O Capítulo 1 apresenta uma introdução sobre os aspectos bioecológicos de M. fimbriolata e o possível papel da espuma produzida pelas ninfas, o qual foi explorado em detalhes ao longo dos demais capítulos. O Capítulo 2 examinou a importância da espuma e de seus compostos químicos na termorregulação das ninfas. O Capítulo 3 explorou a diversidade e composição da comunidade bacteriana presente na espuma, no intestino das ninfas, e no solo próximo à espuma. O Capítulo 4 investigou se a espuma atua na sua proteção das ninfas contra formigas predadoras Solenopsis invicta, e sua irritação tópica a baratas Periplaneta americana. A espuma produzida por M. fimbriolata demonstrou: (i) servir como um importante microhabit térmico, mantendo a temperatura próxima da ideal para o desenvolvimento das ninfas; (ii) abrigar uma diversidade de bactérias previamente reportadas como simbiontes protetivos de insetos e que, provavelmente, são provenientes do intestino das ninfas; e (iii) ser repelente a formigas predadoras e irritante a outro artrópode (baratas). Tomados em conjunto, a espuma produzida por M. fimbriolata serve como uma estratégia termorregulatória e defensiva para as ninfas. Ademais, esta tese serve como base para futuras pesquisas que visam investigar a importância da espuma para o crescimento e desenvolvimento das cigarrinhas.
455

Análise da microbiota fecal em pacientes obesas graves portadores de diabetes mellitus do tipo 2 submetidos à derivação gástrica em Y de Roux / Analysis of fecal microbiote in obese patient with type 2 diabetes mellitus submited to Roux Y Gastric Bypass

Assal, Karina Al 08 August 2018 (has links)
Introdução: A derivação gástrica em Y de Roux (DGYR) é considerada um bom modelo cirúrgico para estudar mecanismos associados à perda de peso e remissão de diabetes mellitus tipo 2 (DM2) em pacientes obesos. Após DGYR, variações na microbiota intestinal podem ocorrer. Objetivo: O objetivo desse estudo foi avaliar o perfil da microbiota intestinal nos períodos pré e pós-operato?rio, precoce e tardio, de pacientes obesas diabéticas submetidas à DGYR, e estudar sua associação com variáveis clínicas, antropométricas, de ingestão alimentar e remissão total de DM2. Métodos: O perfil da microbiota intestinal foi avaliado em amostras fecais obtidas de mulheres obesas com DM2 no momento pré-operatório - basal (n=25), três meses (n=20) e 12 meses (n=14) após DGYR através do sequenciamento do gene RNA ribossomal 16S (16SRNA) com equipamento Illumina MiSeq. Nos três períodos foram coletados dados de ingestão alimentar, composição corporal e marcadores bioquímicos. O diagnóstico de remissão total de DM2 foi obtido após 12 meses de cirurgia, respeitando os critérios da American Diabetes Association (ADA). Resultados: Três meses após DGYR foi observado aumento (n=9) e decréscimo (n=1) de gêneros bacterianos e aumento da riqueza da microbiota intestinal, em relação aos apresentados no momento basal (p <- 0,05). Nenhuma alteração na abundância da microbiota intestinal foi observada entre 3 e 12 meses após a cirurgia (p >,05). No entanto, em relação ao momento pré-operatório, a razão Firmicutes/Bacteroidetes diminuiu após 12 meses da cirurgia (p < 0,037). Houve aumento na riqueza da microbiota que se associou à maior ingestão de fibras e menor ingestão de gorduras (p <- 0,05), em todos os tempos. Ao longo do período pós-operatório, as variáveis metabólicas gerais mostraram melhora, acompanhadas pela redução significativa de peso corpóreo e massa de gordura. Pacientes com remissão total de DM2 (RTDM) (57%) apresentaramno período pré-operatório aumento de três gêneros de bactérias intestinais e diminuição de dois gêneros, comparado aos doentes sem RTDM. Conclusões: Após DGYR, houve alterações quanto à composição do perfil da microbiota intestinal de mulheres obesas diabéticas e aumento da riqueza bacteriana. Os hábitos alimentares também influenciaram a modificação da microbiota fecal. A diferença pré-operatória de gêneros bacterianos encontrada em pacientes com remissão total do DM2 sugere a possibilidade de uso de marcadores microbianos na seleção de pacientes que podem se beneficiar desse efeito metabólico da cirurgia bariátrica / Background: Roux-en-Y gastric bypass (RYGB) is considered a good surgical model to study mechanisms associated with weight loss and remission of type 2 diabetes mellitus (DM2) in obese patients. After RYGB, variations in intestinal microbiota may occur. Objective: To evaluate the profile of the intestinal microbiota in the preoperative and postoperative periods, early and late, of obese diabetic patients submitted to the RYGB, and study the association with clinical, anthropometric, food intake and total remission of DM2. Methods: The intestinal microbiota profile was evaluated in faecal samples obtained from obese women with DM2 before (n = 25), three months (n = 20) and 12 months (n = 14) after RYGB, by extracting ribosomal RNA 16S and sequencing in Illumina MiSeq. Data on food intake, body composition and biochemical markers were collected in the same periods. The diagnosis of total remission of DM2 was obtained after 12 months of surgery, respecting the criteria of the American Diabetes Association (ADA). Results: Three months after DGYR, there was an increase (n = 9) and a decrease (n = 1) in bacterial genus and an increase in intestinal microbiota richness compared to basal (p <= 0.05). No change in intestinal microbiota abundance was observed between 3 and 12 months after surgery (p > 0.05). However, in relation to baseline, the Firmicutes / Bacteroidetes ratio decreased after 12 months of surgery (p < 0.037). There was an increase in the richness of the microbiota that was associated to the higher fiber intake and lower fat intake (p <= 0.05). Over the postoperative period, the general metabolic variables showed improvement, accompanied by a significant reduction in body weight and loss of fat mass. Patients with total remission of DM2 (TRDM) (57%) in the preoperative period, had an increase in tree genus of bacteria and a decrease in two genera of bacteria compared with patients without a total remission of DM2. Conclusions: After RYGB, changes occur in the intestinal microbiota profile of diabetic obese women, in terms of composition and increase of bacterial richness. Feeding habits also influenced the fecal microbiota modification. The difference in bacterial genus found in patients with total remission of DM2 suggests the potential possibility of using microbial markers to select patients who may benefit from this metabolic effect of bariatric surgery
456

Estudo da microbiota de pacientes portadores de doença de Chagas / Study of the microbiota of patients with Chagas disease

Basqueira, Marcela de Souza 20 August 2018 (has links)
INTRODUÇÃO: A doença de Chagas é causada pelo protozoário flagelado Trypanosoma cruzi (T. cruzi) e ainda hoje representa um grande problema de saúde pública tendo infectado mais de oito milhões de pessoas. A patogênese da cardiomiopatia chagásica ainda não é completamente compreendida. A inflamação no miocárdio é intensa em relação ao número de parasitos presentes e também se observa um dano progressivo em outros órgãos como esôfago e cólon em 30% a 40% dos casos em que se diagnosticou a doença. Alguns estudos começaram a mostrar que a resposta imunológica a um parasita pode depender da microbiota intestinal; porém, ainda não existem estudos com a tecnologia de sequenciamento de nova geração (NGS) que descrevam a microbiota intestinal em doença de Chagas. É possível que uma pequena alteração do peristaltismo intestinal, decorrente da infecção por T. cruzi possa alterar a colonização de algumas bactérias as quais podem causar mudanças na reatividade do sistema imune como aumentar a resposta autoimune, gerando maior dano ao coração. OBJETIVO: Este trabalho objetivou descrever a microbiota intestinal de acordo com a forma clínica da doença de Chagas, através da amplificação do gene 16s RNA ribossomal e avaliar seu papel na patogênese da doença. MÉTODO: Foram selecionados 114 indivíduos, sendo 30 portadores da forma cardíaca da doença, 11 com a forma digestiva (megacólon), 32 com a indeterminada e 31 indivíduos saudáveis (controles). De cada um deles, foram coletadas amostras de fezes para a análise da microbiota por meio de técnicas de sequenciamento de nova geração Ion Torrent. Os resultados obtidos foram analisados pelo software QIIME para determinar a população de bactérias presentes nas amostras. A análise estatística foi realizada utilizando-se os testes não paramétricos de Kruskal-Wallis e Mann-Whitney U-test. RESULTADOS: A frequência relativa do filo Verucomicrobia foi significantemente menor no grupo cardíaco em comparação ao grupo controle e as outras formas clínicas: indeterminada e digestiva. Apesar da abundância relativa desse filo ser menor do que 1%, a diferença observada se manteve significante, mesmo após a correção de Bonferroni. CONCLUSÕES: Nosso estudo sugere que uma menor proporção do filo Verrucomicrobia possa estar relacionada ao processo inflamatório na forma cardíaca; porém, ainda pouco se conhece sobre este grupo de bactérias e seus componentes, que nos permita afirmar o seu efetivo papel na forma cardíaca da doença de Chagas / INTRODUCTION: Chagas disease is caused by the flagellate protozoan Trypanosoma cruzi (T.cruzi) and still represents a major public health problem with more than eight million people infected. Chagas cardiomyopathy pathogenesis is still not completely understood. Inflammation in the myocardium is intense in relation to the number of parasites present and progressive damage is also observed in other organs such as the esophagus and colon in 30% to 40% of the cases. Some studies are beginning to show that the immune response to a parasite may depend on the intestinal microbiota. However, there are no studies using NGS technology that describes the intestinal microbiota of Chagas disease. It is possible that a small change in intestinal peristalsis due to T cruzi infection may alter the colonization of some bacteria. These changes could cause changes in the reactivity of the immune system such as increasing the autoimmune response causing greater damage to the heart. OBJECTIVE: This study aimed to describe the intestinal microbiota according to the clinical form of Chagas disease, through amplification of the 16s ribosomal RNA gene and to evaluate its role in the pathogenesis of the disease. METHODS: A total of 114 individuals were selected, 30 of cardiac form of the disease, 11 with the digestive form (megacolon), 32 with indeterminate form and 31 healthy individuals (controls). Stool samples were collected and analysed for the microbiota using Ion Torrent sequencing technique. The results were analyzed by the QIIME software to determine the population of bacteria present in the samples. Statistical was performed using Kruskal-Wallis non-parametric test and Mann-Whitney U-test. RESULTS: The relative frequency of the Verrucomicrobia phylum was significantly lower among the cardiac group when compared to control, indeterminate and digestive form. Our study suggest that the phylum Verrucomicrobia may play a role in the miocardio inflammation process in Chagas disease, however little is known about these bacteria to infer the mechanism
457

Investigação do microbioma intestinal em camundongos deficientes em CRAMP submetidos à sepse experimental / Investigation of the intestinal microbiome in mice deficient in CRAMP subjected to experimental sepsis

Almeida, Marta Lucia de 05 December 2018 (has links)
O microbioma intestinal tem sido associado à sepse, causada por infecção, apresentando respostas imunológicas exacerbadas. O peptídeo antimicrobiano CRAMP atua na imunidade inata com característica ambígua, ora pró-inflamatória ora anti-inflamatória. Nesse estudo, a sepse foi induzida por modelo de ligadura e punção cecal (CLP) e, através de RT-qPCR, o DNA de amostras fecais de camundongos selvagens e deficientes em CRAMP foi analisado. A expressão de Alfa-defensina 5 e Beta-defensina 1 foi investigada em RT-qPCR. Técnicas de imunofluorescência, Elisa e Milliplex, foram utilizadas na quantificação de citocinas - IL-1Beta, IL-6, IL-10, MCP-1 e TNF-Alfa -, e Alfa-defensina 7 e Beta-defensina 1. Os resultados mostraram a intensificação da resposta imune, diante da sepse, com alterações pró-inflamatórias de IL-1Beta, IL-6, MCP-1 e TNF-Alfa e anti-inflamatória de IL-10. A Beta-defensina 1 teve expressão aumentada, enquanto a produção foi mantida ou reduzida nos tecidos, após CLP. A liberação de Alfa-defensina 7 foi ampliada no pulmão de animais selvagens durante a sepse, enquanto a expressão de Alfa-defensina 5 foi reduzida no íleo e cólon. A relação entre o microbioma intestinal e a sepse evidenciou-se com o crescimento da espécie Escherichia coli, enquanto o CRAMP apresentou associação com a espécie Bacteroides vulgatus. Novos estudos permitiram mais conhecimento sobre a interação entre sepse e microbioma intestinal, potencializando o uso de biomarcadores e nova terapêutica na recuperação intestinal, tal como transplante microbiológico fecal / The intestinal microbiome has been associated with sepsis, caused by infection, presenting exacerbated immune responses. The antimicrobial peptide CRAMP acts on innate immunity with ambiguous features, pro-inflammatory and anti-inflammatory. In this study, sepsis was induced by cecal ligation and puncture (CLP) model and, through RT-qPCR, the DNA of fecal samples from wild type and CRAMP-deficient mice was analyzed. Expression of Alpha-defensin 5 and Beta-defensin 1 was investigated in RT-qPCR. Immunofluorescence techniques, Elisa and Milliplex, were used to quantify cytokines - IL-1Beta, IL-6, IL-10, MCP-1 and TNF-Alpha -, and Alpha-defensin 7 and Beta-defensin 1. The results showed the enhancement of the immune response to sepsis with proinflammatory alterations of IL-1Beta, IL-6, MCP-1 and TNF-Alpha and anti-inflammatory IL-10. CRAMP and Beta-defensin 1 peptides had increased expression, while production was maintained or reduced in tissues after CLP. The release of Alpha-defensin 7 was amplified in the lungs of wild type animals during sepsis, while expression of Alpha-defensin 5 was reduced in the ileum and colon. The relationship between the intestinal microbiome and sepsis was evidenced by the growth of Escherichia coli, while CRAMP was associated with Bacteroides vulgatus. New studies have allowed more knowledge about the interaction between sepsis and intestinal microbiome, potentializing the use of biomarkers and new therapy in intestinal recovery, such as fecal microbiological transplantation
458

Baixa diversidade e sucessão microbiana anormal estão associadas à enterocolite necrosante em recém-nascidos prematuros

Dobbler, Priscila Caroline Thiago 07 April 2017 (has links)
Submitted by Ana Damasceno (ana.damasceno@unipampa.edu.br) on 2017-06-07T18:12:48Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Baixa diversidade e sucessão microbiana anormal estão associadas à enterocolite necrosante em recém-nascidos prematuros.pdf: 1587508 bytes, checksum: c407e4cf94f25b2272a7d25213f72873 (MD5) / Made available in DSpace on 2017-06-07T18:12:48Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Baixa diversidade e sucessão microbiana anormal estão associadas à enterocolite necrosante em recém-nascidos prematuros.pdf: 1587508 bytes, checksum: c407e4cf94f25b2272a7d25213f72873 (MD5) Previous issue date: 2017-04-07 / As múltiplas causas de Enterocolite Necrosante (NEC) e seus indicativos clínicos utilizados para o diagnóstico ainda se mantêm elusivos. Biomarcadores alternativos para o diagnóstico precoce de NEC em recém-nascidos prematuros e um melhor entendimento dos fatores de risco para o desenvolvimento de NEC são desafios emergentes. Em uma tentativa de contribuir para a solução deste problema, neste trabalho nós rastreamos as mudanças no microbioma dos recém-nascidos (diversidade microbiana, abundância e estrutura) com NEC, iniciando com a primeira evacuação (mecônio) e continuando até a liberação, e comparamos essas mudanças com os prematuros sem o diagnóstico de NEC. Um estudo metataxonomico foi conduzido usando 88 amostras fecais, a partir da primeira evacuação até a 5ª semana de vida, obtidas de 25 recém-nascidos prematuros (14 controles e 11 casos de NEC) selecionados de um grupo de 52 prematuros. Nossos dados revelaram que casos de NEC apresentaram baixa diversidade e uma transição anormal da comunidade microbiana até o diagnóstico de NEC. Um microrganismo pertencendo a família Enterobacteriaceae foi consistentemente mais abundante em prematuros com NEC do que nos controles, mesmo nas amostras de mecônio, e foi considerado um constituinte chave da comunidade microbiana correlacionada com a doença. Finalmente, nos também detectamos uma distorção na associação micróbio-micróbio nas amostras de mecônio dos casos de NEC. Portanto, nossos dados sugerem que a detecção precoce de elevada dominância de Enterobacteriaceae, baixa diversidade e associações micróbio-micróbio nos primeiros dias de vida poderiam ser utilizados como indicativo de risco de desenvolvimento de Enterocolite Necrosante nas UTIs neonatais brasileiras. / The multiple causes of Necrotizing Enterocolitis (NEC) as well as the clinical predictors used for diagnosis have remained elusive to date. Alternative biomarkers for early diagnosis of NEC in premature infants and a better understanding of risk factors for NEC development are emergent challenges. In attempt to contribute to solve this problem, in this work we tracked the changes in the newborn’s microbiome (microbial diversity, abundance and structure) with Necrotizing Enterocolitis beginning with the first stool (meconium) continuing until discharge and compare those changes with preterns without NEC diagnosis. A metataxonomy study was conducted using 88 fecal samples from the first stool (meconium) until the 5th week of life obtained from 25 preterm babies (14 controls and 11 NEC cases) selected from a cohort of 52 premature infants. Our data revealed low microbial diversity in NEC cases and an abnormal transition of the microbial community until NEC diagnosis. A microbial phylotype belonging to the Enterobacteriaceae family were consistently more abundant in NEC than in the controls even in meconium samples and was considered a key constituent of the microbial community that correlated with the disease. Finally, we also detected a disruption of microbial-microbial associations in the meconium samples of NEC cases. Thus, our data suggests that early detection of high dominance of Enterobacteriaceae, low diversity and altered microbial-microbial associations at the first days of life could be used as an indicative of risk of preterm development of Necrotizing Enterocolitis in Brazilian NICU’s.
459

Statistical methods for analyzing sequencing data with applications in modern biomedical analysis and personalized medicine

Manimaran, Solaiappan 13 March 2017 (has links)
There has been tremendous advancement in sequencing technologies; the rate at which sequencing data can be generated has increased multifold while the cost of sequencing continues on a downward descent. Sequencing data provide novel insights into the ecological environment of microbes as well as human health and disease status but challenge investigators with a variety of computational issues. This thesis focuses on three common problems in the analysis of high-throughput data. The goals of the first project are to (1) develop a statistical framework and a complete software pipeline for metagenomics that identifies microbes to the strain level and thus facilitating a personalized drug treatment targeting the strain; and (2) estimate the relative content of microbes in a sample as accurately and as quickly as possible. The second project focuses on the analysis of the microbiome variation across multiple samples. Studying the variation of microbiomes under different conditions within an organism or environment is the key to diagnosing diseases and providing personalized treatments. The goals are to (1) identify various statistical diversity measures; (2) develop confidence regions for the relative abundance estimates; (3) perform multi-dimensional and differential expression analysis; and (4) develop a complete pipeline for multi-sample microbiome analysis. The third project is focused on batch effect analysis. When analyzing high dimensional data, non-biological experimental variation or “batch effects” confound the true associations between the conditions of interest and the outcome variable. Batch effects exist even after normalization. Hence, unless the batch effects are identified and corrected, any attempts for downstream analyses, will likely be error prone and may lead to false positive results. The goals are to (1) analyze the effect of correlation of the batch adjusted data and develop new techniques to account for correlation in two step hypothesis testing approach; (2) develop a software pipeline to identify whether batch effects are present in the data and adjust for batch effects in a suitable way. In summary, we developed software pipelines called PathoScope, PathoStat and BatchQC as part of these projects and validated our techniques using simulation and real data sets.
460

Estudo da associação entre o microbioma vaginal com variáveis sociodemográficas e de hábitos comportamentais de mulheres brasileiras em idade reprodutiva

Novak, Juliano January 2019 (has links)
Orientador: Camila Marconi / Resumo: A microbiota vaginal normal é composta predominantemente por Lactobacillus spp. que conferem proteção contra infecções por patógenos, por meio da produção de ácido lático, peróxido de hidrogênio e bacteriocinas. Diferentemente, a vaginose bacteriana (VB) é caracterizada pela substituição da microbiota de Lactobacillus spp. por bactérias anaeróbias em sua maioria. A VB é a alteração de microbiota vaginal mais comum em mulheres de idade reprodutiva, acometendo aproximadamente 30% dessa população. Além disso, a VB é fator de risco para aquisição de infecções sexualmente transmissíveis (IST). Diversas características da população já foram associadas à VB, como idade, etnia, comportamentos sexual e de higiene. Entretanto, a real composição da microbiota vaginal só foi possível em 2011 com estudo utilizando o sequenciamento de nova geração do gene bacteriano RNA ribossômico 16S. Foi demonstrado que o microbioma vaginal pode ser classificado em cinco tipos de comunidades bacterianas (community-state types, CST). Quatro dessas CSTs tem predomínio de Lactobacillus: L. crispatus (CSTI), L. gasseri (CST II), L. iners (CST III) e L. jensenii (CST V), enquanto que a CST IV apresenta grande diversidade bacteriana e engloba a maioria dos casos de VB. Apesar de quatro CSTs apresentarem predomínio de Lactobacillus, o papel protetor da CST III, dominada por L. iners, contra aquisição de IST tem se demonstrado menor que os demais. Embora os estudos de microbioma tenham possibilitado conhecer me... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The normal vaginal microbiota is predominantly composed of Lactobacillus spp. which confer protection against pathogen infections through the production of lactic acid, hydrogen peroxide and bacteriocins. Differently, bacterial vaginosis (BV) is characterized by the replacement of the microbiota of Lactobacillus spp. by anaerobic bacteria for the most part. BV is the most common vaginal microbiota alteration in women of reproductive age, affecting approximately 30% of this population. In addition, BV is a risk factor for the acquisition of sexually transmitted infections (STIs). Several characteristics of the population have already been associated with BV, such as age, ethnicity, sexual and hygiene behaviors. However, the actual composition of the vaginal microbiota was only possible in 2011 with study using the new generation sequencing of the bacterial 16S ribosomal RNA gene. It has been shown that the vaginal microbiome can be classified into five types of community-state types (CST). Four of these CSTs have a predominance of Lactobacillus: L. crispatus (CSTI), L. gasseri (CST II), L. iners (CST III) and L. jensenii (CST V), while CST IV shows great bacterial diversity and involve most cases of BV. Although four CSTs have a predominance of Lactobacillus, the protective role of CST III, dominated by L. iners, against IST acquisition has been shown to be lower than the others are. Although microbiome studies have made it possible to know better the relationship between bact... (Complete abstract click electronic access below) / Mestre

Page generated in 0.0352 seconds