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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Correlação da imunoexpressão de podoplanina e ezrin em carcinomas espinocelulares de lábio / Correlation of podoplanin and ezrin immunoexpression in lip squamous cell carcinoma

Alexandre Simões Garcia 27 May 2013 (has links)
A podoplanina humana consiste em uma proteína associada ao processo de invasão das células epiteliais neoplásicas, sendo sua alta expressão correlacionada com um pior prognóstico para os pacientes com câncer de cabeça e pescoço. A porção citoplasmática da podoplanina pode se ligar a ezrin, uma proteína que vem sendo associada com a ocorrência de metástases e menor sobrevida para os pacientes com neoplasias malignas. O objetivo do presente estudo foi avaliar em 48 carcinomas espinocelulares de lábio inferior a expressão imuno-histoquímica da podoplanina e da ezrin, nas células do front de invasão tumoral, e verificar a correlação entre a expressão das duas proteínas nas células epiteliais neoplásicas. A expressão membranosa e citoplasmática da podoplanina e da ezrin foi avaliada nas células neoplásicas periféricas e centrais das ilhotas tumorais, por meio de um método semi-quantitativo de escores. A associação entre a expressão membranosa e citoplasmática da podoplanina e da ezrin nos tumores foi feita pelo teste de qui-quadrado, com nível de significância de 5% e a correlação entre a expressão das duas proteínas foi realizada pelo teste de correlação de Spearman. Os resultados demonstraram uma forte expressão membranosa e citoplasmática da podoplanina nas células periféricas do front de invasão tumoral com ausência desta expressão na região central das ilhotas tumorais. A imunomarcação da ezrin foi homogênea nos tumores e predominantemente citoplasmática. Uma diferença estatisticamente significativa foi encontrada entre a expressão da podoplanina nas células neoplásicas periféricas e centrais (p<0,001), como também entre a expressão da ezrin membranosa e citoplasmática (p<0,001) nos carcinomas espinocelulares de lábio. Houve uma correlação positiva, porém sem significância estatística, entre a expressão da podoplanina membranosa e da ezrin membranosa ou citoplasmática nas células neoplásicas periféricas. Estes resultados comprovam que a podoplanina e ezrin são fortemente expressas pelas células neoplásicas do front de invasão tumoral e sugerem que ambas proteínas podem estar participando do processo de invasão dos carcinomas espinocelulares de lábio. / The human podoplanin consists in a protein associated to the invasion process of the epithelial malignant cells, being your high expression correlated with poor prognosis in patients with head and neck cancer. The cytoplasmic tail of the podoplanin can bind to ezrin, a protein that have been associated with metastasis and lower survival rate in patients with malignant neoplasms. The aim of this study was evaluate in 48 squamous cell carcinomas of the lower lip, the immunohistochemical expression of podoplanin and ezrin, in the invasive front, and verify correlation between the expression of both proteins by epithelial neoplastic cells. The membranous and cytoplasmic expression of podoplanin and ezrin was evaluated in peripheral and central areas of the tumor islets, using a semi-quantitative score method. The association between the membranous and cytoplasmic expression of podoplanin and ezrin in the tumors was performed by chi-square test, using a significance level of 5% and the correlation between the expression of both proteins was performed by Spearman correlation test. The results showed a high membranous and cytoplasmic podoplanin expression in the peripheral cells of the invasive front, with no expression of this protein in the central cells. The ezrin immunostaining was homogeneous and observed mainly in the cytoplasm of malignant cells. A statistically significant difference was found between the expression of podoplanin in peripheral and central tumor cells (p<0,001), as well between the membranous and cytoplasmic expression of ezrin (p<0.001) in squamous cell carcinoma of the lip. There was a positive correlation, but without statistical significance, between the expression of membranous podoplanin and membranous or cytoplasmic ezrin in the peripheral tumor cells. These results prove that podoplanin and ezrin are strongly expressed by malignant cells of the invasive front tumor and suggest that both proteins may be participating in the invasive process of the squamous cell carcinoma of the lip.
62

Expressão de moesina e podoplanina no câncer de boca e sua relação com o processo de invasão tumoral / Expression of moesin and podoplanin in oral cancer and its relation to the process of tumor invasion

Francisco Barbara Abreu Barros 04 April 2014 (has links)
A proteína moesina, uma das proteínas do complexo ERM (ezrina, radixina e moesina), participa do processo de migração de células tumorais controlando a ligação entre o citoesqueleto de actina e os receptores transmembrana. As proteínas ERM vêm sendo investigadas como ligantes de outras glicoproteínas, como a podoplanina, cuja expressão é encontrada em células malignas de diversas neoplasias, incluindo o carcinoma espinocelular (CEC) de boca. O objetivo desse estudo foi avaliar as expressões imuno-histoquímicas da moesina e da podoplanina pelas células malignas no front de invasão de 84 pacientes com CEC de boca e suas associações com a evolução clínica e com o prognóstico dos pacientes. A associação entre a expressão imuno-histoquímica da moesina e da podoplanina pelas células malignas e as variáveis demográficas, clínicas e microscópicas foi avaliada pelo teste qui-quadrado ou teste exato de Fisher. As análises de sobrevida global e livre de doença em 5 e 10 anos foram calculadas pelo estimulador produto-limite de Kaplan-Meier e a comparação das curvas de sobrevida realizada pelo teste de log-rank. Os resultados mostraram que houve expressão da moesina pelas células malignas na região do front de invasão tumoral, entretanto, nenhuma associação estatisticamente significativa foi encontrada entre esta proteína e as características clínicas, demográficas e microscópicas. A expressão da podoplanina, pelas células malignas, foi significativamente associada à radioterapia (p=0,004), à invasão muscular (p=0,006) e ao comprometimento linfonodal (p=0,013). Não houve associação significativa entre a expressão das duas proteínas nos CECs de boca (p=0,460). A forte expressão da moesina pelas células malignas constituiu um fator de prognóstico desfavorável para os pacientes com CEC de boca e estadiamento clínico II e III. O comprometimento linfonodal histopatológico também se mostrou fator de prognóstico significativo para a recidiva da doença (p=0,018). Estes resultados sugerem que a expressão de moesina, pelas células malignas juntamente com o comprometimento linfonodal pode contribuir para determinar os pacientes com CEC de boca que apresentam um pior prognóstico. Além disso, verificamos que as proteínas moesina e podoplanina se expressam pelas células neoplásicas nos CEC de boca mas não parecem estar associadas no processo de invasão tumoral. / The moesin protein, one of the proteins of the ERM complex (ezrin, radixin and moesin) takes part in the migration of tumor cells process by controlling the relation between actin cytoskeleton and transmembrane receptors. The ERM proteins have been investigated as ligants of other glycoproteins, such as podoplanin, which are found in malignant cells of malignant, including oral squamous cell carcinoma (OSCC). The aim of this study was to evaluate the immunohistochemical expressions of moesin and podoplanin by malignant cells in the invasive front of 84 patients with oral squamous carcinoma and its association with clinical outcome and patients\' prognosis. Chi- square or Fisher\'s exact test was used to analyze the association between the moesin and podoplanin expressions by malignant cells and demographic, clinical and microscopic variables in oral squamous cell carcinoma patients. The 5 and 10 years survival rates were calculated by Kaplan-Meier method and the comparison of survival curves were performed using log-rank test. The results showed that there was moesin expression by malignant cells in the invasive front, however, no statistically significant association was found between this protein and demographic, clinical and microscopic features. The expression of podoplanin by malignant cells was significantly associated with radiotherapy (p=0.004), with muscular invasion (p=0.006) and lymph node involvement (p=0.013). There was no significant association between the expression of two proteins in OSCC (p=0.460). The strong expression of moesin by malignant cells was a factor of unfavorable prognosis for patients with OSCC and clinical stage II and III. The histopathological lymph node involvement was also significant prognostic factor for disease recurrence (p=0.018). These results suggest that the expression of moesin by malignant cells and lymph node involvement may help to determine patients with squamous cell carcinoma who have a poor prognosis. Furthermore, we found that moesin and podoplanin proteins are expressed by neoplastic cells in oral squamous cell carcinoma but not appear to be associated in the process of tumor invasion.
63

Addressing Potential Interactions Between Antineoplastics and Dietary Supplements

Bossaer, John B. 01 June 2015 (has links)
Excerpt: Interactions between chemotherapy and dietary or herbal supplements can compromise patient care.
64

Low Rate of Cetuximab Hypersensitivity Reactions in Northeast Tennessee: An Appalachian Effect?

Adams, Brooke C., Street, Sierra D., Crass, Melanie, Bossaer, John B. 20 November 2015 (has links)
Purpose: Cetuximab is a monoclonal antibody with a known risk of hypersensitivity reactions. Early studies showed hypersensitivity reaction rates of 3%, but there appears to be a higher incidence in the southeastern United States. To confirm the findings from nearby institutions that cetuximab-associated hypersensitivity reactions occur in approximately 20% of patients in the southeastern United States. Methods: A retrospective chart review was conducted at Johnson City Medical Center in Johnson City, Tennessee. Each patient’s first infusion was analyzed for hypersensitivity reaction, as well as for demographic information such as allergy and smoking history, pre-medications, and malignancy type. Results: Data from the first infusion of cetuximab were collected for a total of 71 patients with various malignancies. The overall rate of grade 3 or higher hypersensitivity reaction was 1.4%, and total rate of hypersensitivity reaction was 8.5%. These findings more closely correlate to the early clinical trials and package insert. Both severe (p = 0.001) and any-grade (p = 0.002) hypersensitivity reaction occurred less frequently in one Southeastern Appalachian medical center compared to academic medical centers directly to the east and west. Conclusions: Patients in southern Appalachia may be less likely to develop cetuximab hypersensitivity reactions compared to surrounding areas in the Southeastern U.S. These results lend support to the theory that exposure to lonestar ticks (Amblyomma americanum) may be responsible for the development of IgE antibodies to cetuximab that cause hypersensitivity reactions. The development of quick and reliable bedside predictors of cetuximab hypersensitivity reactions may aid clinicians considering the use of cetuximab.
65

Cardiovascular Toxicity and Management of Targeted Cancer Therapy: An Overview for Generalists

Bossaer, John B., Geraci, Stephen A., Chakraborty, Kanishka 01 May 2016 (has links)
The advent of effective oral, molecular-targeted drugs in oncology has changed many incurable malignancies such as chronic myeloid leukemia into chronic diseases similar to coronary artery disease and diabetes mellitus. Oral agents including monoclonal antibodies, kinase inhibitors and hormone receptor blockers offer cancer patients incremental improvements in both overall survival and quality of life. As it is imperative to recognize and manage side effects of platelet inhibitors, beta blockers, statins, HIV drugs, and fluoroquinolones by all healthcare providers, the same holds true for these newer targeted therapies, patients may present to their generalist or other subspecialist with drug-related symptoms. Cardiovascular adverse events are among the most frequent, and potentially serious, health issues in outpatient clinics, and among the most frequent side effects of targeted chemotherapy. Data support improved patient outcomes and satisfaction when primary care and other providers are cognizant of chemotherapy side effects, allowing for earlier intervention and reduction in morbidity and health care costs. With the implementation of accountable care and pay-for-performance, improved communication between generalists and subspecialists is essential to deliver cost-effective patient care.
66

Isavuconazonium Sulfate: A Triazole Prodrug for Invasive Fungal Infections

Murrell, Derek, Bossaer, John B., Carico, Ronald, Harirforoosh, Sam, Cluck, David 29 August 2016 (has links)
Objective: To review the place in therapy of isavuconazole, the active metabolite of isavuconazonium sulfate, via a review of the available literature on drug chemistry, spectrum of activity, pharmacokinetic/pharmacodynamic profile and trials assessing clinical efficacy and safety. Methods: Relevant data, original research articles and reviews, were gathered primarily through the use of a PubMed database search. The search was conducted without date restrictions in order to collect both historical and recent data regarding isavuconazole. Key findings: Isavuconazole is a triazole currently approved not only for use in invasive aspergillosis and mucormycosis but also has demonstrable activity against Candida species and other common fungal pathogens. This drug has features which make it more clinically appealing compared to other azoles with similar indications. In specific, isavuconazole does not require a cyclodextrin vehicle due to its water solubility, and at present, does not require therapeutic drug monitoring. Moreover, isavuconazole has displayed improved safety and tolerability compared to voriconazole. Available data from Phase III clinical trials shows isavuconazole to be a possible therapeutic option to currently available therapies for which it is approved; however, clinical conclusions should be reserved until results have been published and more data from clinical use is reported. Conclusions: Isavuconazole is a new triazole with broad‐spectrum antifungal activity including invasive aspergillosis and mucormycosis.
67

Pharmacological ascorbate enhances oxygen consumption and epigenetic reprogramming in pancreatic cancer

Gibson, Adrienne Rae 01 August 2018 (has links)
Pharmacological ascorbate treatment (P-AscH-, high-dose, intravenous vitamin C) results in a short-term increased flux of H2O2 that is preferentially cytotoxic to cancer cells vs. normal cells. We hypothesized that there may be a sustained effect (> 24 h) of P-AscH- that may contribute to cytotoxicity. P-AscH- significantly increased sustained oxygen consumption (OCR), DCFH-DA oxidation, and extracellular acidification (ECAR) in tumor lines with no change in non-tumorigenic cells. One possible source of this sustained ROS and OCR, the NADPH oxidase family of enzymes Dual Oxidase 1 and 2 (DUOX), which are epigenetically silenced by methylation in vitro and in vivo in PDAC, are up-regulated with P-AscH- treatment. Catalase pretreatment reversed the P-AscH--induced increases in DUOX, while DUOX inhibition partially rescues P-AscH- toxicity. Additionally, nutritional ascorbate is unable to mediate the increase in DUOX expression. Together these results suggest that P-AscH--induced toxicity may be enhanced by late metabolic and epigenetic shifts in tumor cells resulting in a feed-forward mechanism of H2O2 generation and induction of metabolic stress via enhanced DUOX expression and OCR. These data highlight a novel epigenetic mechanism of action for P-AscH-.
68

DNA damage and disruption of cellular bioenergetics contribute to the anti-cancer effects of pharmacological ascorbate

Buranasudja, Visarut 01 December 2018 (has links)
The clinical potential of pharmacological ascorbate (P-AscH-; IV delivery achieving mM concentrations in blood) as an adjuvant in cancer therapy is being re-evaluated. At mM concentrations, P-AscH- is thought to exhibit anti-cancer activity via generation of a flux of H2O2 in tumors, which leads to oxidative distress. Here, we use cell culture models of pancreatic cancer, MIA PaCa-2, PANC-1, and 339 cells, to examine the effects of P-AscH- on DNA damage, and downstream consequences, including changes in bioenergetics. We have found that the high flux of H2O2 produced by P-AscH- induces both nuclear and mitochondrial DNA damage. In response to this DNA damage, we observed that poly (ADP-ribose) polymerase-1 (PARP-1) is hyperactivated, as determined by increased formation of poly (ADP-ribose) polymer. Using our unique absolute quantitation, we found that the P-AscH--mediated the overactivation of PARP-1, which results in consumption of NAD+, and subsequently depletion of ATP (potential energy crisis) leading to mitotic cell death. Time-course studies with MIA PaCa-2 cells showed that the level of NAD+ and ATP were reduced by 80% immediately after a 1-h exposure to P-AscH- (4 mM; 14 pmol cell-1); both species returned to near basal levels within 24 h. In parallel with these metabolic and energetic restorations, the lesions in nuclear DNA were removed within 3 h; however, even after 24 h, lesions in mitochondrial DNA were only partially repaired. We have also found that the Chk1 pathway has a major role in the maintenance of genomic integrity following treatment with P-AscH-. Hence, combinations of P-AscH- and Chk1 inhibitors could have the potential to improve outcomes of cancer treatment. Hyperactivation of PARP-1 and DNA repair are ATP-consuming processes. Using a Seahorse XF96 Analyzer, we observed no changes in OCR or ECAR/PPR following treatment with P-AscH-. OCR and ECAR/PPR together indicate the rate of production of intracellular ATP; therefore, the rate of production is unchanged after challenge with P-AscH-. Thus, the severe decrease in ATP is due solely to increased demand. Genetic deletion and pharmacological inhibition of PARP-1 preserved both NAD+ and ATP; however, the toxicity of P-AscH- remained. These data indicate that loss of NAD+ and ATP are secondary factors in the toxicity of P-AscH-, and damage to DNA is the primary factor. These preclinical findings can guide the best use of P-AscH- as an adjuvant in cancer therapy.
69

Transcription Factor AP-2 in Relation to Serotonergic Functions in the Central Nervous System

Damberg, Mattias January 2002 (has links)
<p>Eukaryotic gene transcription plays a regulatory role in mammalian developmental processes. It has been shown that transcriptional control is an important mechanism for specification of neurotransmitter phenotypes. In the mammalian central nervous system, the transcription factor AP-2 family is one of the critical regulatory factors for neural gene expression and neuronal development. It has been shown that several genes in the monoaminergic systems have AP-2 binding sites in regulatory regions, suggesting a regulatory role of AP-2 also in the adult brain. Brainstem monoamines are implicated in the expression of personality traits and imbalances in these systems may give rise to psychiatric disorders. </p><p>The gene encoding AP-2β includes a polymorphic region consisting of a tetranucleotide repeat of [CAAA]<sub>4-5</sub> in intron 2. Studies on AP-2β genotype in relation to personality and platelet MAO activity, a trait-dependant marker for personality, are presented in this thesis. Furthermore, correlations between brainstem levels of AP-2α and AP-2β and monoamine turnover in projection areas in rat forebrain are reported. These results strengthen the notion that the AP-2 family is important regulators of the monoaminergic systems in the adult brain. Furthermore, two studies are presented in this thesis with analyses indicating a role for AP-2 in the molecular mechanism of antidepressant drugs.</p><p>Altogether, this thesis presents data supporting our notion that the transcription factor AP-2 family is involved in the regulation of the monoaminergic systems both pre- and postnatally, and, therefore, might be involved in the pathophysiology of neuropsychiatric disorders.</p>
70

Semicarbazide-sensitive amine oxidase and vascular complications in diabetes mellitus : Biochemical and molecular aspects

Nordquist, Jenny January 2002 (has links)
<p>Plasma activity of the enzyme semicarbazide-sensitive amine oxidase (SSAO; EC.1.4.3.6) has been reported to be high in disorders such as diabetes mellitus, chronic congestive heart failure and liver cirrhosis. Little is known of how the activity is regulated and, consequently, the cause for these findings is not well understood. Due to the early occurrence of increased enzyme activity in diabetes, in conjunction with the production of highly cytotoxic substances in SSAO-catalysed reactions, it has been speculated that there could be a causal relationship between high SSAO activity and vascular damage. Aminoacetone and methylamine are the best currently known endogenous substrates for human SSAO and the resulting aldehyde-products are methylglyoxal and formaldehyde, respectively. Both of these aldehydes have been shown to be implicated in the formation of advanced glycation end products (AGEs).</p><p>This thesis is based on studies exploring the regulation of SSAO activity and its possible involvement in the development of vascular damage. The results further strengthen the connection between high SSAO activity and the occurrence of vascular damage, since type 2 diabetic patients with retinopathy were found to have higher plasma activities of SSAO and lower urinary concentrations of methylamine than patients with uncomplicated diabetes. From studies on mice, it was also found that an SSAO inhibitor potently reduces the incorporation of methylamine-metabolite in the tissues. By quantifying SSAO-gene expression in alloxan-induced diabetes, increased transcription could be ruled out as a cause for the increased enzyme activity, thereby opening up for the possibility that the activity is regulated post-translationally. In fact, increased enzyme activity in adipose tissue was accompanied by decreased mRNA-levels, suggesting that the gene expression could be negatively controlled by the enzyme activity.</p>

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