• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • Tagged with
  • 38
  • 38
  • 25
  • 23
  • 23
  • 16
  • 14
  • 9
  • 9
  • 9
  • 8
  • 7
  • 7
  • 6
  • 6
  • 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.
21

The Epigenetic Silencing of PMP24 During the Progression of Prostate Cancer from an Androgen-Dependent to Androgen-Independent State in the LNCAP Cell Model: a Dissertation

Wu, Mengchu 20 January 2005 (has links)
One important objective of prostate cancer (PCa) research is to understand the molecular basis underlying the progression of these cancers from an androgen dependent to an androgen independent state. Hypermethylation of the promoter CpG islands is associated with the transcriptional silencing of specific gene sets in each tumor type and subtype. Transcriptional silencing of antitumor genes via CpG island hypermethylation could be a mechanism mediating PCa progression from an androgen-dependent to an androgen-independent state. Hypermethylation associated gene silencing has been reported for a great number of genes in PCa with the exception of the genes that undergo methylation associated silencing specifically during cancer development to androgen independence. The first aim of this thesis is to identify novel glenes which undergo DNA hypermethylation associated gene silencing during the cancer progression. The androgen-dependent (AD, as defined as the inability of celill to proliferate in the absence of androgen) PCa cell line LNCaP gives rise to the androgen-independent (AI) subline LNCaPcs generated by maintaining LNCaP in medium with charcoal-stripped (CS) serum for over 30 passages. This LNCaP cell model was used to identify differentially methylated sequences between the two genomes using the Methylation-Sensitive Restriction Fingerprinting (MSRF) technique. One sequence identified is located in a 5' CpG island, which encompasses part of the promoter, exon 1, and part of intron 1, of the Peroxisomal Membrane Protein 24 KD (PMP24) gene. PMP24 is silenced in concert with the hypermethylation of its CpG island in AI LNCaPcsand PC-3 cell lines. The silencing is reactivated by the treatment with a DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5AZAdC). PMP24 is specifically silenced in PCa cancer cell lines and shows potential antitumor properties. These results demonstrate the utility of MSRF in the identification of novel, differentially methylated DNA sequences in the genome and suggest that hypermethylation-mediated silencing of PMP24 is an epigenetic event involved in PCa progression to androgen independence. The next study investigated the molecular mechanism for DNA methylation associated gene silencing of PMP24 in AI LNCaPcs and PC-3 cell lines. We demonstrated that PMP24 transcription is repressed by the disruption of transcription factor binding to a critical cis-element by hypermethylation of its promoter CpG island. We found a CpG containing activator protein 2 (AP-2) cis-element in the intron 1 of PMP24 whose first CpG dinucleotidle is essential for the sequence-specific protein binding and the promoter activity of the gene. We presented first in cellulo evidence that the methylation of AP-2 cis-element alone but not the whole CpG island, using a newly developed methylated oligonucleotides treatment, is sufficient for the downregulation of PMP24. Our study is the first to report that the silencing mechanism for PMP24 in AI LNCaPcs and PC-3 is mediated by the complete methylation of a single GpG site of AP-2 cis-element in the intron 1 part of the CpG island, which interferes with transcription factor binding. Most interestingly, the promoter CpG island of PMP24 is hypermethylated in AD LNCaP cells with the incomplete methylation specifically at the AP-2 cis-element. The silencing of PMP24 in AD LNCaP cells was reactivated not by the 5AZAdC treatment but by the treatment with Trichostatin A (TSA), a histone deacetylase inhibitor. An alternative silencing mechanism for PMP24 other than the interference with transcription factor binding by methylation is therefore likely involved at this androgen-dependent stage. During the androgen ablation process, this mechanism is either evolved by the spread of methylation in the promoter CpG island or selected against, leading to the methylation-dominant silencing mechanism in the AI cells as seen in LNCaPcsand PC-3 cells. Taken together, this thesis emphasized the important role of DNA methylation in the progression of PCa into androgen independence. Particular respect should be paid to the specific CpG dinucleotides in cis-elements critical for the promoter activity, whose complete methylation could dominate the silencing mechanism which is independent of androgen. This thesis also pointed to the importance of monitoring the effects of cell culture on the methylation status of genes. Most importantly, this thesis raised the possibility that the silencing mechanisms for PMP24 could be different in AD LNCaP cells as compared to AI LNCaPcs and PC-3 cells. Either the evolution of such mechanism or the selectivity against it during the androgen ablation process would result in a methylation-dominant silencing mechanism of the genes such as PMP24 in AI cells and may contribute to the overall androgen independence of the cells.
22

Why are HPV Vaccination Rates So Low?

Gokhale, Kimaya 01 January 2018 (has links)
This thesis attempts to apply the theory of rational disease dynamics to the human papillomavirus by testing whether HPV vaccinations are prevalence elastic. A prevalence elastic relationship suggests that HPV vaccination rates respond positively to increasing prevalence rates of cervical cancer. Prevalence rates are measured both by incidence rates of cervical cancer and by mortality rates of cervical cancer. Data from the NIS-Teen Survey as well as data from the United States Cancer Statistics branch of the Centers for Disease Controls are used to construct a linear regression that controls for income, education levels, proxies for social culture, and proxies for physician access. Incidence was found to have no statistically significant effect on vaccination rates, while mortality rates were found to have a negative relationship with vaccination rates, suggesting that the rational disease dynamics theory does not apply to human papillomavirus and that vaccination rates for HPV are not prevalence elastic.
23

The Effects of Age, Ethnicity, Sexual Dysfunction, Urinary Incontinence, Masculinity, and Relationship with the Partner on the Quality of Life of Men with Prostate Cancer

Ballout, Suha 08 November 2013 (has links)
Prostate cancer, the leading cause of cancer in men, has positive survival rates and constitutes a challenge to men with its side effects. Studies have addressed the bivaritate relationships between prostate cancer treatment side effects masculinity, partner relationship, and quality of life (QOL). However, few studies have highlighted the relationships among prostate cancer treatment side effects (i.e., sexual dysfunction, urinary incontinence), masculinity, and relationship with the partner together on QOL in men. Most studies were conducted with predominately Caucasian sample of men. Miami is a unique multiethnic setting that hosts Cuban, Columbian, Venezuelan, Haitian, other Latin American and Caribbean communities that were not represented in previous literature. The purpose of this study was to examine relative contributions of age, ethnicity, sexual dysfunction, urinary incontinence, masculinity, and perception of the relationship with the partner on the quality of life in men diagnosed with prostate cancer. Data were collected using self administered questionnaires measuring demographic variables, sexual and urinary functioning (UCLA PCI), masculinity (CMNI), partner relationship (DAS), and QOL (SF-36). A total of 117 partnered heterosexual men diagnosed with prostate cancer were recruited from four urology clinics in Miami, Florida. Men were 67.47 (SD = 8.42) years old and identified themselves to be of Hispanic origin (54.3 %, n = 63). Findings demonstrated that there was a significant moderate negative relationship between urinary and sexual functioning of men. There was a significant strong negative association between men’s perceived relationship with partner and masculinity. There was a weak negative relationship between the partner relationship and QOL. Hierarchal multiple regression showed that the partner relationship (β = -.25, t (91) = -2.28, p = .03) significantly contributed overall to QOL. These findings highlight the importance of the relationship satisfaction in the QOL of men with prostate cancer. Nursing interventions to enhance QOL for these men should consider strengthening the relationship and involving the female partner as an active participant.
24

Adaptations of Adipose Tissue Expandability in Gestation are Associated with Maternal Glucose Metabolism

Rojas-Rodriguez, Raziel 17 July 2019 (has links)
Pregnancy induces maternal metabolic adaptations including mild glucose intolerance and weight gain in order to support fetal development and lactation. Adipose tissue (AT) function in gestation is featured by reduced insulin sensitivity and fat mass accrual which partly accounts for the weight gain in pregnant women and adaptation of glucose metabolism. A common metabolic pregnancy complication is gestational diabetes mellitus (GDM), a disease characterized by impaired glucose tolerance with onset in gestation. However, the relationship between AT expandability and glucose metabolism in gestation is not well understood. The goal of this thesis was to investigate the adaptations of human AT expansion induced by pregnancy, how these changes are reflected in pregnancies complicated with GDM and characterize a mouse model to study the mechanisms underlying this disease. This dissertation illustrates that pregnancy promotes AT expandability by a signaling mechanism between placental pregnancy-associated plasma protein-A (PAPP-A) and AT- insulin-like growth factor binding protein-5 (IGFBP5). In addition, gravidas with GDM showed impaired AT expansion. Studies investigating the relationship between PAPP-A and glycemic state demonstrated that low levels of PAPP-A in the 1sttrimester are highly associated with the development of GDM. Moreover, PAPP-A knockout mice exhibit reduced insulin sensitivity and impaired AT growth exclusively in gestation. These results expand the knowledge of AT biology in gestation and have the potential to improve maternal care by proposing PAPP-A as an early biomarker and possible therapeutic for GDM. It also introduces a new mouse model to study the etiology of gestational diabetes.
25

Impact of Parity on Gait Biomechanics

Stein, Bekah P 15 July 2020 (has links)
Background: Symptomatic knee osteoarthritis (OA) is an incurable condition that affects nearly 50% of adults, and women are twice as likely as men to develop OA. Throughout pregnancy, women experience large changes in morphology and gait mechanics, as well as changes in joint loading. It is possible these adaptations could cause lasting changes postpartum, which may potentially contribute to initiation of OA, thereby increasing the overall risk of OA for women. Purpose: This exploratory study looked to identify differences between lower limb gait mechanics of healthy nulliparous women and healthy parous women. Methods: 28 healthy female participants (14 parous, 14 nulliparous) were recruited for the study. Nulliparous participants had never given birth to a child, and were self-reported not pregnant. Parous participants had given birth to at least one full term infant (37 – 42 weeks) without complications between one to five years before data collection. Kinematic and kinetic data was collected for the lower body, using motion capture and in-ground force plates. Participants completed one quiet standing trial, and walked over-ground through the motion capture space at their preferred, fast, and set walking speeds (1.4 m/s). An ANOVA was performed to test if there were significant differences in between groups. Results: Q angle did not differ between groups. There was a significant main effect of group indicating a larger knee flexion angle at toe off (p = 0.060), smaller knee extension moment at heel strike (p = 0.0006), smaller first peak knee flexion moment (p = 0.040), and smaller peak hip adduction moment for the parous group compared to the nulliparous group (p = 0.003). Conclusions: Our data revealed a decrease in the moments experienced, which could possibly lead to degradation of cartilage due to under loading of the joint. We think this may be an indication that pregnancy could increase risk of OA, and therefore more research into this possibility is warranted.
26

Genital Chlamydia Infection is Influenced by the Female Sex Hormones Estrogen and Progesterone in Vivo

Gravitte, Amy Gail 01 December 2021 (has links)
Chlamydia is the most common bacterial sexually transmitted infection in the United States and worldwide. It often goes unnoticed due to lack of symptoms and left untreated it can ascend the female genital tract to cause sequelae like pelvic inflammatory disease and irreversible tubal infertility. In reproductive-aged women, female sex hormones estrogen (E2) and progesterone (P4) concentrations fluctuate during the menstrual cycle and are influenced by hormonal contraceptives and hormone replacement therapy. E2 and P4 influence genital Chlamydia infection in women and mice, but these multifactorial interactions are not entirely mapped out. The complex interplay of E2 and P4 with Chlamydia and the host response demand further study to determine the effect of hormonal environment and host susceptibility to Chlamydia. E2 primarily signals through estrogen receptors (ER) ERα and ERβ. We used ERα or ERβ knockout (KO) mice to study the role of E2 and ERs in chlamydial progression and examined the host immune response at day 9 post-infection, when we expected the immune response to be the most robust. ERαKO, but not ERβKO mice had significant differences in the progression of Chlamydia and the host immune response. Future studies should test the immune response at additional timepoints, and a model should be utilized wherein ERα and ERβ are simultaneously silenced by chemical knockdown of ERβ in ERα knockout mice using ER agonist ICI 182, 680. 3 Mice are widely used in Chlamydia research, but due to its short estrus cycle, infection cannot be established naturally before infected cells are shed. To overcome this, mice are pretreated with depot medroxyprogesterone acetate (DMPA), an exogenous progesterone that halts the estrus cycle. However, a mouse model not reliant on DMPA pretreatment is needed because 1.) DMPA can affect the immune response and 2.) the hormonal environment in women is not static. Our model uses mice that are ovariectomized to stop the production of endogenous E2 and P4, then treated with physiologically relevant levels of E2 and P4 via implantation of a hormone-filled capsule. We observed that E2 protected mice from Chlamydia, making our model a good alternative for in vivo Chlamydia studies.
27

Chemotherapy-Induced Premature Menopause Among Latina Women With Breast Cancer: An Interpretive Description: A Dissertation

Brisbois, Maryellen D. 14 August 2013 (has links)
The description and interpretation of Latinas’ experience with chemotherapyinduced premature menopause from breast cancer treatment were explored in this study, which utilized an interpretive descriptive method from a feminist lens, and Knobf’s (1998, 2002) “Carrying on” theory. The specific aims of the study and the interview questions were guided by the state of the science literature. Overall, the impact of physiological effects, psychosocial effects, barriers, influencing factors that made their experience easier or harder, and how participants adjusted to a cancer diagnosis, treatment course, and menopause transition were described as bigger than the menopause experience alone. Participants also described a period of uncertainty or “ever-changing landscape” that began at the time of diagnosis and continued through survivorship. The impact of information, access to healthcare, acculturation levels, support, and a sense of control were elucidated as important factors in “working through” the experience. A range of collateral data sources were employed. Study limitations and future implications for practice, research, and health policy were demarcated.
28

Predicting Other Cause Mortality Risk for Older Men with Localized Prostate Cancer: A Dissertation

Frendl, Daniel M. 26 March 2015 (has links)
Background: Overtreatment of localized prostate cancer (PCa) is a concern as many men die of other causes prior to experiencing a treatment benefit. This dissertation characterizes the need for assessing other cause mortality (OCM) risk in older men with PCa and informs efforts to identify patients most likely to benefit from definitive PCa treatment. Methods: Using the linked Surveillance Epidemiology and End Results-Medicare Health Outcomes Survey database, 2,931 men (mean age=75) newly diagnosed with clinical stage T1a-T3a PCa from 1998-2009 were identified. Survival analysis methods were used to compare observed 10-year OCM by primary treatment type. Age and health factors predictive of primary treatment type were assessed with multinomial logistic regression. Predicted mortality estimates from Social Security life tables (recommended for life expectancy evaluation) and two OCM risk estimation tools were compared to observed rates. An improved OCM prediction model was developed fitting Fine and Gray competing risks models for 10-year OCM with age, sociodemographic, comorbidity, activities of daily living, and patient-reported health data as predictors. The tools’ ability to discriminate between patients who died and those who did not was evaluated with Harrell’s c-index (range 0.5-1), which also guided new model selection. Results: Fifty-four percent of older men with localized PCa underwent radiotherapy while 13% underwent prostatectomy. Twenty-three percent of those treated with radiotherapy and 12% of those undergoing prostatectomy experienced OCM within 10 years of treatment and thus were considered overtreated. Health factors indicative of a shorter life expectancy (increased comorbidity, worse physical health, smoking) had little to no association with radiotherapy assignment but were significantly related to reductions in the likelihood of undergoing prostatectomy. Social Security life tables overestimated mortality risk and discriminated poorly between men who died and those who did not over 10 years (c-index=0.59). Existing OCM risk estimation tools were less likely to overestimate OCM rates and had limited but improved discrimination (c-index=0.64). A risk model developed with self-reported age, Charlson comorbidity index score, overall health (excellent-good/fair/poor), smoking, and marital status predictors had improved discrimination (c-index=0.70). Conclusions: Overtreatment of older men with PCa is primarily attributable to radiotherapy and may be reduced by pretreatment assessment of mortality-related health factors. This dissertation provides a prognostic model which utilizes a set of five self-reported characteristics that better identify patients likely to die of OCM within 10 years of diagnosis than age and comorbidity-based assessments alone.
29

The Role of Non-Neuronal Acetylcholine in Urogenital Chlamydial Infection

Lockhart, Jessica R 01 December 2018 (has links) (PDF)
Chlamydia trachomatiscauses a bacterial sexually transmitted infection, Chlamydia, that is often chronic and casues reproductive complications in women. We hypothesized that Chlamydia infection increases local acetylcholine (ACh) production, which regulates the host’s inflammatory response to the infection. Female mice infected with C. muridarumwere sacrificed at days 3, 9, 15, and 21 post-infection, genital tract tissues harvested, and immunohistochemistry performed to enumerate ACh-producing cells. Infection increased the number of ACh-producing cells in cervical tissue at days 3,15, and 21 post-infection (pi), uterine tissue at day 3 and 9 pi, and ovarian tissue day 3, 15, and 21 pi. These findings suggest that C. trachomatis increases ACh production, which may suppress the host’s immunity and aid in establishing chronic infection.
30

Role of WFS1 in Regulating Endoplasmic Reticulum Stress Signaling: A Dissertation

Fonseca, Sonya G. 24 February 2009 (has links)
The endoplasmic reticulum (ER) is a multi-functional cellular compartment that functions in protein folding, lipid biosynthesis, and calcium homeostasis. Perturbations to ER function lead to the dysregulation of ER homeostasis, causing the accumulation of unfolded and misfolded proteins in the cell. This is a state of ER stress. ER stress elicits a cytoprotective, adaptive signaling cascade to mitigate stress, the Unfolded Protein Response (UPR). As long as the UPR can moderate stress, cells can produce the proper amount of proteins and maintain a state of homeostasis. If the UPR, however, is dysfunctional and fails to achieve this, cells will undergo apoptosis. Diabetes mellitus is a group of metabolic disorders characterized by persistent high blood glucose levels. The pathogenesis of this disease involves pancreatic β-cell dysfunction: an abnormality in the primary function of the β-cell, insulin production and secretion. Activation of the UPR is critical to pancreatic β-cell survival, where a disruption in ER stress signaling can lead to cell death and consequently diabetes. There are several models of ER stress leading to diabetes. Wolcott-Rallison syndrome, for example, occurs when there is a mutation in the gene encoding one of the master regulators of the UPR, PKR-like ER kinase (PERK). In this dissertation, we show that Wolfram Syndrome 1 (WFS1), an ER transmembrane protein, is a component of the UPR and is a downstream target of two of the master regulators of the UPR, Inositol Requiring 1 (IRE1) and PERK. WFS1 mutations lead to Wolfram syndrome, a non-autoimmune form of type 1 diabetes accompanied by optical atrophy and other neurological disorders. It has been shown that patients develop diabetes due to the selective loss of their pancreatic β-cells. Here we define the underlying molecular mechanism of β-cell loss in Wolfram syndrome, and link this cell loss to ER stress and a dysfunction in a component of the UPR, WFS1. We show that WFS1 expression is localized to the β-cell of the pancreas, it is upregulated during insulin secretion and ER stress, and its inactivation leads to chronic ER stress and apoptosis. This dissertation also reveals the previously unknown function of WFS1 in the UPR. Positive regulation of the UPR has been extensively studied, however, the precise mechanisms of negative regulation of this signaling pathway have not. Here we report that WFS1 regulates a key transcription factor of the UPR, activating transcription factor 6 (ATF6), through the ubiquitin-proteasome pathway. WFS1 expression decreases expression levels of ATF6 target genes and represses ATF6-mediated activation of the ER stress response (ERSE) promoter. WFS1 recruits and stabilizes an E3 ubiquitin ligase, HMG-CoA reductase degradation protein 1 (HRD1), on the ER membrane. The WFS1-HRD1 complex recruits ATF6 to the proteasome and enhances its ubiquitination and proteasome-mediated degradation, leading to suppression of the UPR under non-stress conditions. In response to ER stress, ATF6 is released from WFS1 and activates the UPR to mitigate ER stress. This body of work reveals a novel role for WFS1 in the UPR, and a novel mechanism for regulating ER stress signaling. These findings also indicate that hyperactivation of the UPR can lead to cellular dysfunction and death. This supports the notion that tight regulation of ER stress signaling is crucial to cell survival. This unanticipated role of WFS1 for a feedback loop of the UPR is relevant to diseases caused by chronic hyperactivation of ER stress signaling network such as pancreatic β-cell death in diabetes and neurodegeneration.

Page generated in 0.0467 seconds