Introdução: o uso da videolaparoscopia na doença de Crohn (DC) teve seu início nos anos 90, com ressalvas à possível dificuldade técnica que a DC complexa ou recorrente poderia impor à sua realização. Diversos estudos ao longo das décadas de 90 e 2000 mostraram ser a mesma factível, quando comparada à laparoscopia para DC primária, além de demonstrarem maior benefício da laparoscopia comparada à cirurgia aberta/convencional nos casos de DC recorrente. Entretanto, não houve estudos sobre resultados cirúrgicos após repetidas ressecções laparoscópicas. Objetivo: avaliar resultados pós-operatórios em curto prazo no tratamento da DC, comparando pacientes submetidos a uma segunda ressecção intestinal laparoscópica e pacientes sem cirurgia prévia. Além disso, comparar os mesmos resultados pós-operatórios entre pacientes submetidos a uma segunda ressecção intestinal laparoscópica e pacientes sendo submetidos a laparoscopia para DC e história prévia de ressecção intestinal prévia por laparotomia. Materiais e métodos: foi realizado análise retrospectiva a partir de base de dados mantida prospectivamente de pacientes submetidos a laparoscopia para tratamento da DC no Hospital Beaujon, França, entre 2005 e 2010. Os desfechos analisados foram: conversão para cirurgia aberta, tempo operatório, taxa de enterotomias inadvertidas no intra-operatório, morbidade, necessidade de reintervenção (cirúrgica ou radiológica) e tempo total de hospitalização. Resultados: foram analisados 18 pacientes com laparoscopia prévia (grupo A), 90 pacientes sem cirurgia prévia (grupo B) e 26 pacientes com laparotomia prévia (grupo C). Em nossa análise principal, comparando os grupos A e B, vemos grupos semelhantes em relação a dados demográficos, exceto maior número de casos complexos no grupo A (83,3 vs 46,7%; p=0,005) e tipo de operação realizada (p < 0,001). Quanto aos resultados, apenas o tempo operatório foi significativamente mais longo no grupo A (180 minutos vs. 150 minutos; p=0,013). A taxa de conversão, enterotomia inadvertida, morbidade, necessidade de reintervenção e tempo de hospitalização foram similares entre os grupos. Em nossa segunda análise, entre os grupos A e C, não houve diferença significativa quanto aos mesmos resultados analisados. Conclusão: apesar de um maior tempo operatório, uma segunda ressecção laparoscópica mantém os mesmos benefícios vistos em uma ressecção intestinal laparoscópica primária. Os mesmos benefícios são vistos quando os resultados são comparados com pacientes submetidos previamente a uma ressecção intestinal por laparotomia, em especial quando nas mãos de equipe experiente / Introduction: the use of laparoscopy in Crohn\'s disease (CD) had its beginning in the 90s, despite the possible challenge of technical difficulty that the complex or recurrent CD could impose to its realization. Numerous studies over the decades of 90 and 2000 showed laparoscopy in recurrent CD to be feasible compared to laparoscopy for primary CD, and have also shown the benefits of laparoscopic compared to open conventional surgery in patients with recurrent CD. However, there were no studies on surgical outcomes after repeated laparoscopic resections. Objective: 1. to evaluate postoperative short-term results regarding surgical treatment of CD, comparing patients who underwent a second laparoscopic bowel resection and patients without prior surgery. 2. to compare the same postoperative results among patients who underwent a second laparoscopic bowel resection patients and patients undergoing laparoscopic resection with history of prior intestinal resection by laparotomy. Materials and methods: a retrospective analysis from prospectively maintained database of patients undergoing laparoscopy for treatment of CD in Hospital Beaujon, France, between 2005 and 2010, was performed. The outcomes analyzed were: conversion to open surgery, operative time, intraoperative inadvertent enterotomy, morbidity, need for re-intervention (surgical or radiological) and length of hospitalization. Results: 18 patients with previous laparoscopy (group A), 90 patients without previous surgery (group B) and 26 patients with previous laparotomy (group C) were included. In our main analysis, comparing the groups A and B, groups were similar in respect to demographic data, except number of complex cases in group A (83.3 vs 46.7%; p = 0.005) and type of surgery performed (p < 0.001). As for the results, operative time was significantly longer in group A (180 minutes vs. 150 minutes; p = 0.013). Conversion rate, inadvertent enterotomy, morbidity, need for re-intervention and hospital stay were similar between groups. In our second analysis, between groups A and C, there was no significant difference between groups regarding the same variables. Conclusion. In spite of a longer operative time, a second laparoscopic resection guarantees the same benefits seen in a primary laparoscopic bowel resection. The same benefits are kept compared to patients who underwent prior bowel resection by laparotomy, especially when in the hands of experienced staff

Objetivo: Avaliar o prognóstico clínico do transplante multivisceral (TMV) na vigência de trombose difusa do sistema porto-mesentérico. Introdução. O transplante hepático (TH) na vigência de cirrose e trombose difusa do sistema porto-mesentérico é controverso e muitas vezes contraindicado em muitos centros de transplante hepático. O transplante hepático utilizando técnicas alternativas como a hemitransposição portocava falha na eliminação de complicações provenientes da hipertensão portal. O TMV substitui o fígado e todo o sistema venoso porto-mesentérico. Métodos: Uma base de dados de pacientes submetidos a transplante intestinal foi mantida com análise prospectiva de resultados. O diagnóstico de trombose difusa do sistema porto-mesentérico foi estabelecido através de tomografia abdominal em fases arterial e venosa, ou por ressonância magnética com reconstrução venosa. Resultados: Vinte e cinco pacientes com trombose de porta, estádio IV, foram submetidos ao TMV. Onze pacientes receberam transplante renal concomitante. Rejeição aguda confirmada por biópsia foi notada em cinco pacientes, que foram tratados com sucesso. Com um seguimento médio de 2,8 anos, a sobrevida de enxertos e pacientes foi de 80%, 72% e 72%, respectivamente. Até a presente data, todos os sobreviventes estão com boa função de enxerto e sem nenhum sintoma ou evidência de hipertensão portal. Conclusão: O TMV deve ser considerado como opção para o tratamento de pacientes com trombose portomesentérica difusa. O transplante multivisceral é o único procedimento que reverte completamente a hipertensão portal e a doença de base com uma sobrevida superior ao TH com reconstruções vasculares alternativas / Objective: To evaluate the clinical outcomes of multivisceral transplantation (MVT) in the setting of diffuse thrombosis of the portomesenteric venous system. Background: Liver transplantation (LT) in the face of cirrhosis and diffuse portomesenteric thrombosis (DPMT) is controversial and contraindicated in many transplant centers. LT using alternative techniques such as portocaval hemitransposition fails to eliminate complications of portal hypertension. MVT replaces the liver and the thrombosed portomesenteric system. Methods: A database of intestinal transplant patients was maintained with prospective analysis of outcomes. The diagnosis of diffuse PMT was established with dual-phase abdominal computed tomography or magnetic resonance imaging with venous reconstruction. Results: Twentyfive patients with grade IV DPMT received 25 MVT. Eleven patients underwent simultaneous cadaveric kidney transplantation. Biopsy proven acute cellular rejection was noted in 5 recipients, which was treated successfully. With a median follow-up of 2.8 years, patient and graft survival were 80%, 72%, and 72% at 1, 3, and 5 years, respectively. To date, all survivors have good graft function without any signs of residual/recurrent features of portal hypertension. Conclusions: MVT can be considered as an option for the treatment of patients with diffuse DPMT. MVT is the only procedure that completely reverses portal hypertension and addresses the primary disease, while achieving superior survival results in comparison to the alternative vascular reconstructions

Objetivo: Investigar a deglutição em indivíduos com a Síndrome Richieri Costa-Pereira (SRCP), com o propósito de verificar a presença sintomas de disfagia por parte dos cuidadores e paciente, bem como sinais de disfagia. Casuística e Método: Estudo retrospectivo e prospectivo, no qual foram avaliados 19 indivíduos com a SRCP, entre 26 dias e 30 anos de idade, de ambos os sexos. Foram levantados sintomas de disfagia por meio de entrevista, bem como análise de prontuários, seguida de avaliação clínica e instrumental da deglutição (videoendoscopia da deglutição - VED) para investigar os sinais de disfagia. A deglutição foi classificada de acordo com a Functional Oral Intake Scale - FOIS e a Escala de Comprometimento Funcional da Deglutição - ECFD. Resultados: Todos os indivíduos maiores de 4 anos (n=12) se alimentavam por via oral exclusiva (VO), sem restrições (FOIS nível 7), assim realizaram única avaliação, apesar de constatada a presença de sinais de comprometimento da deglutição em 8 casos na ECFD. Os indivíduos menores de 3 meses de idade (n=7), com alimentação exclusiva por sonda alimentadora na primeira avaliação (FOIS nível 1), foram acompanhados por apresentarem sintomas e sinais de disfagia detectados nas avaliações clínica e instrumental. Ao longo do estudo, foi verificado o desenvolvimento de mecanismo de proteção das vias aéreas com melhora da deglutição, sendo que 4 casos passaram a se alimentar exclusivamente por VO na última avaliação. Conclusão: Sintomas de disfagia, principalmente na população infantil, estão presentes, assim como sinais de disfagia, em diferentes graus, durante toda a evolução do tratamento, mesmo na ausência de sintomas; os indivíduos com a SRCP desenvolveram mecanismo de proteção das vias aéreas realizando a deglutição de maneira adaptada e estabelecendo assim condições para a alimentação por via oral exclusiva. / Objective: To investigate swallowing in individuals with Richieri Costa-Pereira syndrome (RCPS), in order to verify the presence of dysphagia symptoms by caregivers and patients, as well as dysphagia signs. Methods: A retrospective and prospective study in which 19 subjects with RCPS, aged 26 days - 30 years, both genders, were evaluated. Data from dysphagia symptoms were collected through interviews and records analysis, followed by clinical and instrumental swallowing evaluation (Flexible Endoscopic Evaluation of Swallowing FEES) to investigate dysphagia signs. Swallowing was classified according to the Functional Oral Intake Scale - FOIS and Swallowing Functional Impairment Scale - SFIS. Results: A single assessment was performed in all subjects older than 4 years (n=12). They were exclusively oral fed without restrictions (FOIS level 7) although impaired swallowing signs were observed in 8 cases on the ECFD. Individuals younger than 3 months (n=7), were exclusively tube fed in the first evaluation (FOIS level 1), and were followed up for presenting dysphagia symptoms and signs detected in clinical and instrumental evaluation. The development of airway protection mechanism with swallowing improvement was verified during the study, and 4 cases (n=7) were exclusively oral fed in the last assessment. Conclusion: Dysphagia symptoms are present especially in children as well as dysphagia signs, which may vary in degrees, even when no symptoms are reported throughout treatment evolution. Individuals with RCPS developed protective airways mechanism performing adapted swallowing and thereby establishing conditions for exclusively oral feeding.

Orientador: Maria Beatriz Duarte Gavião / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-24T16:58:30Z (GMT). No. of bitstreams: 1 Strini_PolyanneJunqueiraSilvaAndresen_D.pdf: 1536403 bytes, checksum: 660235bf6e3720dfc8efe64a5a11f203 (MD5) Previous issue date: 2014 / Resumo: O número de idosos está aumentando mundialmente, fato que sugere a necessidade de melhor entendimento de fatores individuais e ambientais relacionados ao envelhecimento. O objetivo deste estudo foi analisar a qualidade de vida geral, a avaliação subjetiva das condições bucais, os níveis de depressão e estresse percebido, presença de disfunções orofaciais e níveis salivares de cortisol e alfa-amilase em idosos institucionalizados. A amostra foi composta por 76 indivíduos de ambos os gêneros, com idade mínima de 60 anos, submetidos a exame clínico intraoral para a verificação da presença de próteses. Foram aplicados os questionários "Medical Outcomes Study 36-Item Short-Form Health Survey" (SF-36) para a avaliação da qualidade de vida geral; "Oral Health Assessment Index" (GOHAI) para a avaliação subjetiva das condições bucais; "Perceived Stress Scale" (PSS), para avaliação da percepção de situações estressantes; "Geriatric Depression Scale" (GDS-15) para a avaliação da presença de depressão e "Nordic Orofacial Test ¿ Screening" (NOT-S) para a avaliação da presença de disfunções orofaciais. As amostras de saliva foram coletadas durante dois dias, ao acordar e 30 minutos após, obtendo a Resposta do Cortisol ao Acordar - ACR e a Resposta da Alfa-amilase ao Acordar - AAAR. Os dados foram submetidos à análise estatística por meio do coeficiente de correlação de Spearman, regressão linear múltipla (?=0.05), teste Chi-square ou Exato de Fisher e teste Kruskal-Wallis. Os resultados mostraram correlação positiva entre o valor total de GOHAI e SF-36, correlação negativa entre o domínio função física de GOHAI e PSS e escores de GDS-15. A regressão linear múltipla mostrou uma interrelação entre os escores de PSS e domínio físico do GOHAI porém não houve associação com ACR e AAAR. Correlação positiva foi observada entre o domínio Função Psicossocial de GOHAI e NOT-S para os indíviduos com próteses em ambas arcadas dentárias e entre GOHAI total e NOT-S para os indivíduos com pelo menos uma prótese. Pode-se concluir que os indivíduos avaliaram a condição bucal como desfavorável e da mesma forma consideraram a saúde geral como inapropriada. Da mesma forma, os indivíduos portadores de próteses ou não podem apresentar dificuldades relacionadas com aspectos físicos e psicológicos, que podem causar dor e desconforto ocasionando impactos na qualidade de vida / Abstract: The number of elderly is increasing worldwide, which suggests the need for better understanding of individual and environmental factors related to aging. The aim of this study was to assess overall quality of life and subjective assessment of oral conditions, levels of depression and perceived stress, presence of orofacial dysfunctions and levels of salivary cortisol and alpha-amylase in institutionalized elderly. The sample comprised 76 subjects of both genders, with minimum age 60 years, submitted to intraoral clinical examination to verify the presence of prostheses. Questionnaire "Medical Outcomes Study 36-Item Short-Form Health Survey" (SF-36) was applied to assess overall quality of life; "Oral Health Assessment Index" (GOHAI) for the subjective assessment of oral conditions; "Perceived Stress Scale" (PSS), to evaluate the perception of stressful situations; "Geriatric Depression Scale" (GDS-15) for evaluating the presence of depression and "Nordic Orofacial Test - Screening" (NOT-S) to assess the presence of orofacial dysfunctions. Multiple linear regression showed an interrelationship between PSS scores and physical domain of GOHAI but there was no association with ACR and AAAR. Positive correlation was observed between Psychosocial Function GOHAI domain and NOT-S for individuals with prostheses in both dental arches and between total NOT-S and GOHAI for individuals with at least one prostheses. Similarly, individuals with prostheses or not may present difficulties related to physical and psychological aspects, which may cause pain and discomfort impacting on quality of life / Doutorado / Anatomia / Doutora em Biologia Buco-Dental

In mammals, newly synthesized proteins destined for secretion are translocated cotranslationally into the lumen of the Endoplasmic Reticulum (ER). Once inside, these nascent polypeptide chains are bound by a lumenal ER protein called BiP (Immunoglobulin Binding Protein) or Grp 78 (Glucose Regulated Protein 78). It is hypothesized that this binding is necessary to protect the nascent chains until they are properly folded or assembled with other subunits. When the proteins are folded and assembled, they are released from BiP by a process that is dependent on ATP hydrolysis. Since ATP is synthesized mainly in the mitochondria, we hypothesized that there must be an ATP transporter in the ER which would allow the protein mediated transport of ATP from the cytosol into the ER lumen. We studied the transport of ATP in vitro and found that ATP enters the lumen of the ER in a saturable manner with a Kmapp~3μM. ATP transport is dependent on time, protein, and vesicle integrity, it is also inhibited by the general anion transport inhibitor, 4,4' diisothiocyano-2,2'-disulfonic acid stilbene (DIDS). We also found that the transport was inhibited by membrane impermeable protein modifying agents such as N-ethlymaleamide (NEM) and Pronase when added to intact ER vesicles. These results suggest that the transport is mediated by a protein with an active cytoplasmic face. Using monoclonal and polyclonal antibodies to BiP and Grp94 (another resident ER protein) and U.V. crosslinking, we demonstrated that after transport of ATPα32P into intact vesicles, radiolabeled BiP and Grp94 could be immunoprecipitated. We also found that labeling of lumenal proteins with ATP is dependent on the transport of ATP. Finally using ATP labeled with 35S, we concluded that BiP was able to bind intact ATP and we confirmed earlier work that BiP was thiophosphorylated while Grp94 is not. The second area of study involves processes that occur further along the secretory pathway in the Golgi apparatus. It was known from previous work that the nucleotide sugar substrates necessary for the synthesis of the linkage region, UDP-xylose (UDP-Xyl), UDP-galactose (UDP-Gal) and UDP-glucuronic acid (UDP-GlcA) were transported into the Golgi apparatus from the cytosol via protein mediated transporters. In order to eventually purify one of these transporter proteins, we wanted to reconstitute their activities. We were able to reconstitute the activities that exhibited kinetic parameters and inhibitor sensitivities very similar to those seen in intact Golgi vesicles. In the case of UDP-xylose it was necessary to prepare the liposomes using endogenous Golgi lipids in order to get transport activity similar to that seen in the intact Golgi vesicles. This suggested a specific lipid requirement for the UDP-xylose transporter. These transporters seem to be antiporters, whereby the nucleotide sugar enters the lumen of the Golgi coupled to the equimolar exit of the corresponding nucleoside monophosphate (Hirschberg, C.B. and Snider, M.D. 1987). We also showed that we could reproduce the hypothesized antiporter system in the reconstituted proteoliposomes by preloading the proteoliposomes with the putative antiporter molecule UMP. The rationale for developing the reconstituted system is eventually to use this system to purify one of these nucleotide sugar translocators. In the last set of studies, I have shown that this reconstituted system can be used to monitor the purification of the UDP-galactose translocator. Using column chromatography we were able to purify this membrane translocator protein 45,000 fold from a rat liver homogenate.

Background: Recent national trends and distribution of ileal pouch-anal anastomosis (IPAA) procedures for patients with ulcerative colitis (UC) are unknown. We examined the frequency of use of elective IPAA procedures among patients with UC and the distribution of IPAA procedures across more than 140 U.S. academic medical centers and their affiliates. Methods: Data were obtained from the University HealthSystem Consortium for patients with a primary diagnosis of UC admitted electively between 2012 and 2015. Results: The mean age of the study population (n=6,875) was 43 years and 57% were men. Among these, one-third (n=2,307) underwent an IPAA, while two-thirds (n=4,568) underwent colectomy, proctectomy, proctocolectomy or other procedures. The proportion of IPAA cases among all elective admissions was relatively stable at 33-35% during the years under study. A total of 131 hospitals, out of 279 hospitals participating in the UHC, performed IPAA. The median number of IPAA cases performed annually was 1.9 [IQR 0.8 – 4.3]. Nearly one half (48%) of these cases were performed by the top ten hospitals. Overall, only a total of 30 centers performed ³ five elective IPAA cases annually. Conclusions: Although the frequency of elective IPAA surgery in recent years has been stable, nearly one half of all IPAA cases was performed at ten hospitals. The concentration of IPAA cases at high-volume centers, and the steady number of cases performed annually, have potential implications for fellowship training, patient clinical outcomes and access to care.

Background: Treatment decisions for elderly patients with gallbladder pathology are complex. Little is known about what factors go into treatment decisions in this population. We used Medicare data to examine gender-based differences in the use of cholecystectomy vs. cholecystostomy tube placement in elderly patients with acute cholecystitis. Methods: We queried a 5% random sample of Medicare data (2009-2011) for patients >65 admitted for acute cholecystitis (by ICD-9 code) who subsequently underwent a cholecystectomy and/or cholecystostomy tube placement. Demographic information (age, race), clinical characteristics (Elixhauser index, presence of biliary pathology), and hospital outcomes (case fatality rate, length of stay, need for ICU care) were compared by gender. A multivariable model was used to examine predictors of cholecystectomy vs. cholecystostomy tube placement. Results: Of 4063 patients admitted with cholecystitis undergoing the procedures of interest just over half (58%) were women. The majority of patients (93%) underwent cholecystectomy. Compared to women, men were younger (average age 76 vs. 78, p value < 0.01) and had few comorbidities (average Elixhauser 1.2 vs. 1.4 p value < 0.01). Case fatality rate was similar between men (2.5%) and women (2.4% p value 0.48). A higher percentage of men spent time in the ICU (36%) compared to women (31% p value < 0.01). On multivariable analysis men were 30% less likely to undergo cholecystectomy (OR 0.69, 95% CI 0.53-0.91). Conclusion: Elderly men are less likely than elderly women to undergo cholecystectomy for acute cholecystitis despite being younger with less co morbidity and are more likely to spend time in the ICU. More research is needed to determine whether a difference in treatment is contributing to the higher rate of ICU utilization in elderly men with acute cholecystitis.

Two decades after the discovery of the Hepatitis C Virus (HCV), Hepatitis C infection still persists to be a global health problem. With the recent approval of the first set of directly acting antivirals (DAAs), the rate of sustained viral response for HCV-infected patients increased significantly. However, a complete cure has not been found yet. Drug development efforts primarily target NS3/4A protease, bifunctional serine protease-RNA helicase of HCV. HCV NS3/4A is critical in viral function; protease domain processes the viral polyprotein and helicase domain aids replication of HCV genome by unwinding double stranded RNA transcripts produced by NS5B, RNA-dependent RNA polymerase of HCV. Protease and helicase domains can be isolated, expressed and purified separately while retaining function. Isolated domains of HCV NS3/4A have been extensively used in biochemical and biophysical studies for scientific and therapeutic purposes to evaluate functional capability and mechanism. However, these domains are highly interdependent and modulate the activities of each other bidirectionally. Interdomain dependence was demonstrated in comparative studies where activities of isolated domains versus the full length protein were evaluated. Nevertheless, specific factors affecting interdependence have not been thoroughly studied. Chapter II investigates the domain-domain interface formed between protease and helicase domains as a determinant in interdependence. Molecular dynamics simulations performed on single chain NS3/4A constructs demonstrated the importance of interface in the coupled dynamics of the two domains. The role of the interface in interdomain communication was experimentally probed by disrupting the domain-domain interface through Ala-scanning mutations in selected residues in the interface with significant buried surface areas. These interface mutants were assayed for both helicase and protease related activities. Instead of downregulating the activities of either domain, interface mutants caused enhancement of protease and helicase activities. In addition, the interface had minimal effect in RNA unwinding activity of the helicase domain, the mere presence of the protease domain was the main protagonist in elevated RNA unwinding activity. In conclusion, I suspect that the interface formed between the domains is transient in nature and plays a regulatory role more than a functional role. In addition, I found results supporting the suggestion that an alternate domain-domain arrangement other than what is observed in crystal structures is the active, biologically relevant conformation for both the helicase and the protease. Chapter III investigates structural features of HCV NS3/4A protease inhibitors in relation to effects on inhibitor potency, susceptibility to drug resistance and modulation of potency by the helicase domain. Nearly all NS3/4A protease inhibitors share common features, with major differences only in bulky P2 extension groups and macrocyclization statuses. Enzymatic inhibition profiles of different drugs were analyzed for wildtype isolated protease domain and single chain NS3/4A helicase-protease construct, their multi drug resistant variants, and additional helicase mutants. Inhibitor potency was mainly influenced by macrocyclization, where macrocyclic drugs were significantly more potent compared to acyclic variants. Potency loss with respect to resistance mutations primarily depended on the P2 extension, while macrocyclization had minimal effect except for P2-P4 macrocyclic compounds which were up to an order of magnitude more susceptible to mutations A156T and, in lesser extent, D168A. Modulation by helicase domain was also dependent on P2 extension, although opposite trends were observed for danoprevir analogs versus others. In conclusion, this study provides a basis for future inhibitor development in both avoiding drug resistance and exploitation of the helicase domain for additional efficacy. In this thesis, I have provided evidence further supporting and revealing the details of domain-domain dependency in HCV NS3/4A. Lessons learned here will aid future research for dissecting the interdependency to gain a better understanding of HCV NS3/4A function, which can possibly be extended to all Flaviviridae NS3 protease-helicase complexes. In addition, interdomain dependence can be exploited in future drug development efforts to create better drugs that will pave the way to an effective cure.

Telomere length has been shown to be a critical determinant of T cell replicative capacity and in vivo persistence in humans. We evaluated telomere lengths in virus-specific T cells to understand how they may both shape and be changed by the maintenance of memory T cells during a subsequent virus re-infection or reactivation. We used longitudinal peripheral blood samples from healthy donors and samples from a long-term HCV clinical interferon therapy trial to test our hypotheses. To assess T cell telomere lengths, I developed novel modifications to the flow cytometry fluorescence in situ hybridization (flowFISH) assay. These flowFISH modifications were necessary to enable quantification of telomere length in activated, proliferating T cells. Adoption of a fixation-permeabilization protocol with RNA nuclease treatment prior to telomere probe hybridization were required to produce telomere length estimates that were consistent with a conventional telomere restriction fragment length Southern blot assay. We hypothesized that exposure to a non-recurring, acute virus infection would produce memory T cells with longer telomeres than those specific for recurring or reactivating virus infections. We used two acute viruses, vaccinia virus (VACV) and influenza A virus (IAV) and two latent-reactivating herpesviruses, cytomegalovirus (CMV) and varicella zoster virus (VZV) for these studies. Combining a proliferation assay with flowFISH, I found telomeres in VACV-specific CD4 + T cells were longer than those specific for the recurring exposure IAV; data which support my hypothesis. Counter to my hypothesis, CMV-specific CD4 + T cells had longer telomeres than IAV-specific CD4 + T cells. We assessed virus-specific CD4 + T cell telomere length in five donors over a period of 8-10 years which allowed us to develop a linear model of average virus-specific telomere length changes. These studies also found evidence of long telomere, virus-specific CD45RA + T cell populations whose depletion may precede an increased susceptibility to latent virus reactivation. I tested the hypothesis that type I interferon therapy would accelerate T cell telomere loss using PBMC samples from a cohort of chronic hepatitis C virus patients who either did or did not receive an extended course of treatment with interferon-alpha. Accelerated telomere losses occurred in naïve T cells in the interferon therapy group and were concentrated in the first half of 48 months of interferon therapy. Steady accumulation of CD57 + memory T cells in the control group, but not the therapy group, suggested that interferon also accelerated memory turnover. Based on our data, I present proposed models of memory T cell maintenance and impacts of T cell telomere length loss as we age.

Pancreatic cancer is the 4th leading cause of cancer related death in the United States with a median survival time of less than 6 months. Pancreatic ductal adenocarcinoma (PDAC) accounts for greater than 85% of all pancreatic cancers, and is marked by early and frequent mutation of the KRAS oncogene, with activating KRAS mutations present in over 90% of PDAC. To date, though, targeting activated KRAS for cancer treatment has been very difficult, and targeted therapies are currently being sought for the downstream effectors of activated KRAS. Activation of KRAS stimulates multiple signaling pathways, including the MEK-ERK and PI3K-AKT signaling cascades, but the role of downstream effectors in pancreatic tumor initiation and progression remains unclear. I therefore used primary pancreatic ductal epithelial cells (PDECs), the putative cell of origin for PDAC, to determine the role of specific downstream signaling pathways in KRAS activated pancreatic tumor initiation. As one third of KRAS wild type PDACs harbor activating mutations in BRAF , and KRAS and BRAF mutations appear to be mutually exclusive, I also sought to determine the effect of activated BRAF (BRAF V600E ) expression on PDECs and the signaling requirements downstream of BRAF. I found that both KRAS G12D and BRAF V600E expressing PDECs displayed increased proliferation relative to GFP expressing controls, as well as increased PDEC survival after challenge with apoptotic stimuli. This survival was found to depend on both the MEK-ERK and PI3K-AKT signaling cascades. Surprisingly, I found that this survival is also dependent on the IGF1R, and that activation of PI3K/AKT signaling occurs downstream of MEK/ERK activation, and is dependent on signaling through the IGF1R. Consistent with this, I find increased IGF2 expression in KRAS G12D and BRAF V600E expressing PDECs, and show that ectopic expression of IGF2 rescues survival in PDECs with inhibited MEK, but not PI3K. Finally, I showed that the expression of KRAS G12D or BRAF V600E in PDECs lacking both the Ink4a/Arf and Trp53 tumor suppressors is sufficient for tumor formation following orthotopic transplant of PDECs, and that IGF1R knockdown impairs KRAS and BRAF-induced tumor formation in this model. In addition to these findings within PDECs, I demonstrate that KRAS G12D or BRAF V600E expressing tumor cell lines differ in MEK-ERK and PI3K-AKT signaling from PDECs. In contrast to KRAS G12D or BRAF V600E expressing PDECs, activation of AKT at serine 473 in the KRAS G12D or BRAF V600E expressing tumor cell lines does not lie downstream of MEK, and only the inhibition of PI3K alone or both MEK and the IGF1R simultaneously results in loss of tumor cell line survival. However, inhibition of MEK, PI3K, or the IGF1R in KRAS G12D or BRAF V600E expressing tumor cell lines also resulted in decreased proliferation relative to DMSO treated cells, demonstrating that all three signaling cascades remain important for tumor cell growth and are therefore viable options for pancreatic cancer therapeutics.