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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.
351

Importância da ocorrência de estro e do diâmetro folicular no momento da inseminação em protocolos de sincronização da ovulação para inseminação artificial em tempo fixo em fêmeas zebuínas de corte / Importance of occurrence of estrus and the ovarian follicle diameter at insemination in synchronization of ovulation protocols for timed artificial insemination in zebu beef cows

Sá Filho, Manoel Francisco de 06 November 2012 (has links)
O objetivo deste trabalho foi avaliar as associações entre a ocorrência de estro após os protocolos de sincronização da ovulação e diâmetro folicular no momento da inseminação artificial em tempo fixo (IATF) nas respostas ovarianas e na taxa de concepção após IATF em fêmeas zebuínas de corte. Assim, avaliaram-se as possíveis implicações práticas do uso dessas informações para a melhoria dos programas de IATF em fêmeas zebuínas lactantes. Essa tese é dividida em três capítulos. No primeiro capítulo, estudou-se a associação entre o diâmetro folicular no momento da IATF com as respostas das fêmeas após sincronização da ovulação e IATF. Observou-se que o aumento do diâmetro folicular no momento da IATF aumenta tanto a taxa de ovulação, quanto a taxa de concepção após IATF. O segundo capítulo relata a realização de quatro estudos onde foram avaliadas as associações da ocorrência de estro no intervalo entre o final do protocolo de sincronização e o momento da IATF na resposta ovariana e a taxa de concepção após a IATF. Foi observado que a ocorrência de estro após o protocolo de sincronização está associada à melhores respostas ovarianas, melhor função luteínica no ciclo subsequente e melhor taxa de concepção após IATF. Por fim, o terceiro capítulo trata da utilização das informações supracitadas para a seleção de fêmeas com maior probabilidade de gestação após IATF para receberem sêmen sexado. Os resultados são indicativos de que é possível obter maiores taxas de concepção após uso de sêmen sexado ou convencional nas fêmeas selecionadas pela ocorrência de estro ou pela presença de folículo de maior diâmetro no momento da IATF. Portanto, estratégias para melhorar a ocorrência de estro e o diâmetro folicular no momento da IATF são importantes para o sucesso dos programas de sincronização da ovulação para IATF de fêmeas zebuínas, e tais critérios podem ser utilizados na seleção de fêmeas de melhor resposta para receberem sêmen sexado. / The objective of the present thesis was to evaluate the associations between the occurrence of estrus after synchronization of ovulation protocols and ovarian follicle diameter at the timed artificial insemination (TAI) on ovarian responses and conception rates after TAI in Zebu beef females. Finally, there were evaluated some practical tools using established information to select cows to receive great value semen during TAI program. This thesis was divided into three chapters. In the first chapter, it was evaluated the association between ovarian follicle diameter at the TAI moment on ovarian responses and pregnancy per TAI. It was observed that the increase in the ovarian follicle diameter at TAI increases both the ovulation and conception rates following the TAI synchronization protocol. In the second chapter, there were four studies in which was analyzed the effect of occurrence of estrus between the end of the synchronization protocol and the IATF. It was observed that the occurrence of estrus after synchronization protocol is associated with higher ovarian responses, greater luteal function on subsequent estrous cycle and higher pregnancy per TAI. Finally, the third chapter, the established information were used to select females with greater odds of pregnancy to receive sex-sorted sperm. It was possible to obtain higher conception rates following the selection of females through the occurrence of estrus or the presence of larger ovarian follicle at the time of TAI after the use either sex-sorted or non sex-sorted sperm. Therefore strategies to improve the occurrence of estrus and the ovarian follicle diameter at TAI moment are important to improve the reproductive outcomes following synchronization of ovulation protocols for TAI in lactating zebu cows. Besides, such selection criteria can be used to select females with greater odds of pregnancy to receive sex-sorted sperm.
352

The Role of RalA and RalB in Cancer

Falsetti, Samuel C 07 April 2008 (has links)
Ras genes are frequently mutated in human cancers and present compelling targets for therapeutic intervention. While previous attempts to directly inhibit oncogenic Ras function have largely been unsuccessful use of targeted agents to inhibit the three primary oncogenic pathways activated by mutated Ras: RalGEF-Ral, PI3K-Akt and Raf- MEK-Erk, is an area of intense investigation. Here, we describe the ability of a novel pharmacological inhibitor of geranylgeranyltransferase I, GGTI-2417, to inhibit Ral prenylation and localization. We further used a Ral rescue system to selectively preserve RalA and RalB function and localization during GGTI-2417 treatment and determine the precise roles for inhibition of Ral prenylation in the GGTI anti-cancer response. Specifically, we determined inhibition of RalA is required for GGTI-attenuation of anchorage independent growth whereas inhibition of RalB is required for inhibition of proliferation, induction of apoptosis, suppression of survivin and induction of p27Kip1. We next determined the role of RalGEF-Ral signaling as well as PI3K-Akt and Raf-MEKErk signal transduction pathways in an in vitro model of human ovarian surface epithelial (T80 HOSE) cell Ras-dependent transformation. Using both small interfering RNA (siRNA) and pharmacological inhibitors of Ral, PI3K and MEK we determined that Ras signaling via Ral and PI3K but not MEK is required for ovarian oncogenesis. Furthermore, stable expression of Ras mutants unable to activate Raf-MEK-Erk signaling were able to robustly transform T80 cells. Since we had confirmed the importance of Ral proteins to human epithelial malignancies we next sought to explore the molecular interactions governing Ral transformation using a proteomics approach to rapidly identify proposed Ral interacting partners. Using immunoprecipition of transiently overexpressed FLAG-tagged RalA and RalB followed by 1D-gel separation and tandem MS/MS analysis we determined a database of proposed Ral interacting proteins. One of these, RACK1, is a validated RalA and RalB interacting protein which is at least partially required for Ras and Ral transformation. These results provide both a strong impetus and a solid basis for future studies into the mechanisms of RalA- and RalB- dependent transformation.
353

BRCA1 185delAG Mutant Protein, BRAt, Amplifies Caspase-Mediated Apoptosis and Maspin Expression in Ovarian Cells

O'Donnell, Joshua D 04 April 2008 (has links)
Ovarian cancer is a deadly disease that kills an estimated 15,000 women annually in the United States. It is estimated that approximately 10% of ovarian cancers are due to familial inheritance. The most commonly mutated genes in familial ovarian cancer are BRCA1 and BRCA2. It has been reported that cells carrying the BRCA1 185delAG mutation undergo an enhanced caspase-3 mediated apoptotic response. Here, we report on the transfection of cDNA coding for the putative truncated protein product of the BRCA1 185delAG mutant gene into BRCA1 wild-type human immortalized ovarian surface epithelial (IOSE) cells and ovarian cancer cells. Cells transfected with the BRCA1 185delAG truncation protein (BRAt) showed increased levels of active caspase 3, increased cleavage of caspase 3 substrates, PARP and DFF45, and decreased XIAP and cIAP1 following staurosporine (STS) treatment. BRAt also reduced Akt phosphorylation and over expression of activated Akt in BRAt cells restored caspase-3 activity to that seen in wild type cells. Further, BRAt expression increased chemosensitivity in platinum resistant ovarian cancer cells. Similarly, maspin protein has been shown to sensitize breast carcinoma cells to STS-induced apoptosis. We provide the first evidence that BRAt is sufficient to induce maspin protein in IOSE cells. IOSE cell lines carrying the BRCA1 185delAG mutation showed higher maspin levels than wild-type BRCA1 IOSE cell lines. BRCA1 wild-type IOSE cells were transfected with BRAt protein and showed increased maspin mRNA levels and increased nuclear maspin protein levels as compared to control cells. Additionally, both heterozygous carriers of the BRCA1 185delAG mutation and cells transfected with BRAt protein show an increased ability to activate the maspin promoter as compared to control cells. The transcription factor AP1 is at least partially required for full activation of the maspin promoter in BRAt cells, as siRNA directed towards c-jun decreased activation of the full-length maspin promoter. Taken together, our data demonstrate that truncated proteins arising from BRCA1 185delAG mutation increase Akt-mediated apoptosis by increasing nuclear maspin expression, suggesting a possible mechanism by which ovarian cancer patients with germline BRCA1 mutations may respond better to chemotherapy.
354

Characterization of Iron Response in Gynecological Cell Lines

Bauckman, Kyle A. 25 March 2014 (has links)
Ovarian carcinoma afflicts over 22,000 women each year with a 5 year survival rate of only 18% for stage IV patients [23]. Current treatment options are limited due to high rates of drug resistance and recurrence. Further, the identity of "precursor lesions" which give rise to various subclasses of epithelial ovarian cancer has been evasive. This is due to discovery of the cancer at already an advanced stage. Interestingly, endometriosis a benign but invasive gynecological disease has been described as a "precursor lesion" in the development of specific subtypes of ovarian cancer. Endometriotic cyst development involves the accumulation of "old blood" components including iron-rich heme. Published evidence implicates excess iron that is involved in the transformation of normal surface epithelial cells inducing morphological characteristics of clear cell ovarian cancer cells [13, 34]. Due to excess iron in endometriotic cysts, this essential element may play a transformative role in the development of clear cell ovarian cancer and possibly other subtypes [13, 35-38]. Further, studies show increased risk of developing ovarian cancer, particularly clear cell and endometrioid ovarian subtypes, in patients diagnosed with endometriosis [36, 37, 39, 40] . This thesis aims to initiate an investigation regarding the contribution of iron and endometriotic lesions in the development and progression of specific subtypes of epithelial ovarian cancers. Since there is a lack of well-validated and characterized endometriotic cell lines that could be used for endometriosis studies, we sought to develop an immortalized cell line for future endometriotic in vitro and in vivo studies. Thus, in Chapter 3 we present our efforts in developing a novel life-span extended epithelial endometriotic cell line. The cells were derived from the endometriotic tissue of a patient with endometriosis. We describe our attempts at immortalization and the characterization of this endometriotic cell line in relation to previously reported/available endometrial/endometriotic cell lines. In Chapter 4 we investigated the role of iron in modulating functional aspects of various gynecological cell lines. Although our expectation was that iron could transform normal ovarian surface epithelial cells (OSE) to a carcinoma-like phenotype, we instead discovered that ovarian cell lines containing Ras mutations (or with H-Ras overexpression) responded to iron (presented as ferric ammonium citrate (FAC)) with a reduced growth response. Further treatment with iron induced an apoptotic/necrotic death response in the Ras mutated HEY ovarian carcinoma cell line. Interestingly, we identified that iron induced autophagic activation in all ovarian cell lines investigate, although autophagy contributed only modestly to the cell death event. Furthermore, we noted that iron activated the MAPK pathway and its inhibition (via U0126, a MAPK inhibitor) allowed survival of cells. In Chapter 5, we briefly explore the role of iron in ovarian cell types growing under anchorage-independent conditions. We found that the cell lines displayed increased cleaved PARP and apoptosis when placed under these conditions. Treatment with iron led to a reduction in cleaved PARP suggesting that iron promotes cell survival in anchorage-independent conditions. Further, inhibition of autophagy via chloroquine led to increased cleaved PARP suggesting that autophagy may mediate a protective role against anchorage-independent apoptotic response In Chapter 6, we attempted to elucidate the downstream mechanism following Ras/MAPK activation in response to iron. This study identified several signaling pathways including that involved in translational control, iron metabolism, as well as mitochondrial function. The inhibition of the iron regulatory and translation control pathway did not significantly lead to rescue of iron-induced cell death of Ras mutated/overexpressed cells. However, we noted mitochondrial stress and damage including altered expression of mitochondrial markers (TOM20/TOM70, outer membrane transporters) which occurred concurrently with iron-induced cell death. The inhibition of iron import into mitochondria using a calcium uniporter channel inhibitor (Ru360) led to a marked reversal of the cell death response. Collectively, these studies suggest that increased mitochondrial permeabilization may be responsible for the observed iron-induced cell death response. Overall, the studies presented in this thesis have revealed novel responses to iron in the gynecological cell types investigated. We initially sought to understand the role of iron in precursor lesions which included the development of a novel life-span extended epithelial endometriotic cell type. Remarkably, our findings revealed a Ras driven sensitivity to excess iron. Treatment with iron caused decreased cell growth and increased cell death in cell types containing Ras mutation/overexpression. Further, we found that the mechanism leading to the iron-induced cell death events was mediated via the MAPK pathway. We then determined that the cell death response was associated with mitochondrial permeabilization. Loss of mitochondrial integrity occurred in Ras sensitive cell lines and inhibition of iron import into the mitochondria (via the calcium uniporter channel inhibitor, Ru360) led to reversal of this response. We show herein the cellular response of excess iron and its potential implication in ovarian cancer research.
355

Growth Factor-Mediated Telomerase Activity in Ovarian Cancer Cells

Bermudez, Yira 11 April 2007 (has links)
Ovarian cancer is the leading cause of gynecological cancer death in the United States. Even though no single genetic alteration can be attributed to all ovarian cancers, 90% of ovarian tumors express telomerase, a ribonucleoprotein that elongates telomeric (TTAGGG)n repeats de novo. In normal somatic cells, telomerase is absent. In cancer cells, the re-expression of telomerase allows senescence to be bypassed contributing to cellular immortalization, a key step for cellular transformation, making telomerase a potentially important target for therapeutic intervention. Ovarian cancer cells secrete vascular endothelial growth factor (VEGF) and lysophosphatidic acid (LPA) that feedback through their receptors present on ovarian cancer cells to promote cell growth. Since telomerase can be regulated by growth factors, I examined VEGF regulation of telomerase activity and the possible contribution of LPA as an upstream regulator of VEGF-mediated telomerase activity in ovarian cancer. My data reveal that both VEGF and LPA upregulate telomerase activity by ERK 1/2-dependent transcriptional activation within the -976 to the -378 bp hTERT promoter regions where Sp1 is one of the major mediators of VEGF- and LPA-induced transactivation of hTERT. It also identifies telomerase as a novel molecular target of LPA as well as a target of VEGF in non-endothelial cells. In addition I found that, vitamin E, a dietary supplement able to degrade and suppress LPA activity, consistently abrogrates LPA-mediated telomerase activity through transcriptional inhibition of the hTERT -976 to -578 bp promoter regions. Lastly, since epidermal growth factor (EGF) promotes ovarian surface epithelial (OSE) cell growth and EGF receptors are frequently constitutively activated in ovarian cancers, the potential contribution of EGF in the regulation of telomerase activity was also examined. While none of the ovarian cancer cell lines examined produced large amounts of EGF, EGF stimulation of telomerase activity was mediated by Sp1 and c-Myc transcription factors within the hTERT core promoter in an ERK 1/2 /Pyk2-dependent manner. In conclusion, my research shows differential regulation of telomerase activity by growth factor and/or anti-oxidant nutraceuticals. In the future, these factors may be exploited as adjuvant therapy for improved chemotherapeutic benefit to decrease the mortality associated with ovarian cancer.
356

A POPULATION-BASED ANALYSIS OF PATIENT AGE AND OTHER DISPARITIES IN THE TREATMENT OF OVARIAN CANCER IN CENTRAL APPALACHIA AND KENTUCKY

Ore, Robert 01 January 2019 (has links)
Objectives: Adherence to National Comprehensive Cancer Network (NCCN) guidelines for ovarian cancer treatment improves patient outcomes. The aim of this study was to assess disparities associated with ovarian cancer treatment in the state of Kentucky and central Appalachia. Methods: Data on patients diagnosed as having ovarian cancer from 2007 through 2011 were extracted from administrative claims-linked Kentucky Cancer Registry data. NCCN compliance was defined by stage, grade, surgical procedure, and chemotherapy. Selection criteria were reviewed carefully to ensure data quality and accuracy. Descriptive analysis, logistic regression, and Cox regression analyses were performed to examine factors associated with guidelines compliance and survival. Results: Most women were age 65 years or older (62.5%), had high grade (65.9%) and advanced stage (61.0%) ovarian cancer. Two-thirds of cases (65.9%) received NCCN-recommended treatment for ovarian cancer. The hazard ratio (HR) of death for women who did not receive NCCN-compliant care was 62% higher compared to the women who did receive NCCN compliant treatment (HR 1.62, 95% CI 1.11-2.35). Results from the logistic regression showed that NCCN-compliant treatment was more likely for: women age 65-74 years compared to age 20-49 (OR=3.32, 95% CI=1.32- 8.32), late stage compared to early stage cancers (OR 0.32, 95% CI 0.20-0.53), receipt of care at tertiary hospitals (OR=1.92, 95% CI=1.10-3.34), and privately insured compared to Medicaid (OR=0.31, 95% CI=0.13-0.77) or Medicare (OR=0.31, 95% CI=0.15-0.66). Conclusions: When the treatment of ovarian cancer did not follow NCCN-recommendations, patients had a significantly higher risk of death. Women were less likely to receive NCCN-compliant care if they were of younger age (20-49 years), had early stage disease, were not privately insured, or had care provided at a non-tertiary hospital.
357

Role and Regulation of SnoN/SkiL and PLSCR1 Located at 3q26.2 and 3q23, Respectively, in Ovarian Cancer Pathophysiology

Kodigepalli, Madhav Karthik 18 September 2014 (has links)
Ovarian cancer is one of the most common causes of gynecological cancer related deaths in women. In 2014, the estimated number of deaths due to ovarian cancer is 14,270 with occurrence of over 22, 240 new cases (National Cancer Institute, http://seer.cancer.gov/statfacts/html/ovary.html). Despite improvement in treatment strategies, the 5-year survival rate is still below 50% mainly due to chemoresistance and relapse. Amplification of chromosomal region 3q26 is a common characteristic in various epithelial cancers including ovarian cancer. This region harbors various oncogenes including the TGFβ signaling mediators EVI1 and SnoN/SkiL, PKCι and PIK3CA amplified at 3q26.2 and 3q26.3, respectively, in ovarian cancers. Previous studies indicate that these genes can exhibit cooperative oncogenicity by cross-regulating one another and facilitating cancer development. Our earlier studies demonstrated that treatment of ovarian cancer cells with arsenic trioxide (As2O3) promotes cytoprotective autophagy regulated by induction of SnoN to antagonize the cytotoxic effects of As2O3. Since exact mechanisms underlying As2O3-induced SnoN expression and cytoprotective responses were unclear, we hypothesized that SnoN may be regulated by signaling pathways involving genes amplified at the 3q26 locus. Phospholipid scramblase 1 (PLSCR1) is located at 3q23 proximal to the amplified 3q26 region. It had been implicated in disruption of plasma membrane asymmetry by mediating phospholipid scrambling, a process critical for cellular events such as blood coagulation and apoptosis. However, recent findings have led to more investigations on the role and regulation of PLSCR1 in cancer development and immune responses. PLSCR1 expression is regulated by various stimuli including growth factors (EGF, G-CSF, and SCF), cytokines (IFN), and differentiation-inducing agents (ATRA). Despite these studies, transcriptional regulation of PLSCR1 remains incompletely understood. Numerous studies have suggested a critical role for PLSCR1 in the pathophysiology of various cancers including leukemia, ovarian cancer, colorectal cancer, and metastatic liver cancer. However, the precise contribution of PLSCR1 and its regulation in ovarian cancer development is unclear. Since PLSCR1 (at 3q23) is located in close proximity to SnoN/SkiL (at 3q26.2), we hypothesized that PLSCR1 expression in ovarian cancer cells could be regulated by SnoN. Herein, we present studies that primarily focus on understanding the role and regulation of SnoN/SkiL (a TGFβ pathway regulator) and PLSCR1 (an interferon-regulated gene), which are located at 3q26.2 and 3q23, respectively, in epithelial ovarian cancer. In Chapter 3, we determined that activation of the PI3K signaling pathway mediates SnoN expression and cytoprotective responses upon stimulation of ovarian cancer cells with As2O3. We first identified that As2O3 stimulation leads to activation of EGFR and its downstream signaling mediators as well as modulates its interaction with the adaptor proteins, ShcA and Grb2. Interestingly, while treatment with a general SFK inhibitor (PP2), reduced the As2O3-induced EGFR activation and SnoN induction, a more specific inhibitor SU6656 did not alter SnoN expression. Further, via studies utilizing specific inhibitors and siRNA targeting PI3K, we determined that inhibition of PI3K signaling pathway decreases SnoN induction and increases apoptosis in ovarian cancer cells in response to As2O3. This suggests that PI3K (PIK3CA) activity is required for the As2O3-mediated SnoN induction and the cell survival responses in ovarian cancer cells. Finally, we determined by siRNA-mediated knockdown that EGFR and MAPK1 alter As2O3-induced cell death response independently of SnoN induction. In Chapter 4, via bioinformatic analyses, we identified that PLSCR1 DNA copy number and mRNA expression is elevated in ovarian cancer patients and cell lines relative to immortalized (Tag/hTERT) normal ovarian surface epithelial (OSE) cells. Interestingly, altered PLSCR1 DNA and mRNA levels were correlated with SnoN in ovarian cancers. We next identified that SnoN knockdown leads to a significant (~35%, P2O3 transcriptionally downregulates PLSCR1 in a ROS-independent mechanism. Furthermore, PLSCR1 knockdown, similar to SnoN knockdown increases ovarian cancer cell sensitivity to As2O3. PLSCR1 knockdown increases cleaved PARP (marker of apoptosis) with a consequent reduction in LC3-II levels (marker of autophagosomes). Collectively, these studies implicate PLSCR1 in the pathophysiology of ovarian cancers and in altering the chemotherapeutic responses in ovarian cancer cells. PLSCR1 is an IFN-regulated gene and mediates antiviral/immune responses. More recent studies in plasmacytoid dendritic cells have implicated PLSCR1 in regulating TLR9 signaling upon stimulation with CpG ODN. However, whether PLSCR1 could mediate the innate immune responses upon stimulation with dsDNA remained unclear. In Chapter 5, we identified that stimulation of normal ovarian and mammary epithelial cells with dsDNA (empty plasmid) markedly induces PLSCR1 consequent with activation of IRF3, a downstream mediator of TLR signaling that transcriptionally regulates the expression of type 1 IFNs. Interestingly, IRF3 knockdown ablates the dsDNA-induced PLSCR1 expression suggesting that PLSCR1 induction in response to dsDNA could be mediated by IRF3. Additionally, we have determined that dsDNA stimulation induces nucleic acid sensing TLRs, TLR9 and TLR4 as well as IFN-α and IFN-β mRNAs. Interestingly, dsDNA stimulation did not induce PLSCR1 or IRF3 activation in ovarian cancer cells suggesting that the mechanisms of IRF3 activation and PLSCR1 induction in response to dsDNA might be dysregulated in ovarian cancers. Collectively, our studies demonstrate a possible synergistic role of SnoN and PLSCR1 in ovarian cancer pathophysiology and suggest a potentially dysregulated role of PLSCR1 in the dsDNA-induced immune responses of malignant epithelial cells relative to normal epithelial cells. These studies could potentially lead to development of a novel combinatorial therapeutic strategy that targets both these molecules for improving treatment of patients with ovarian carcinoma.
358

Control of ovarian development in the Yabby (Cherax destructor)

McRae, Thomas Geoffrey, mikewood@deakin.edu.au January 1998 (has links)
A study under controlled conditions of ovarian development and rematuration in the yabby (Cherax destructot) was undertaken. The purpose of the study was to improve fundamental understanding of the reproductive biology of the species and provide a basis for application to hatchery management in culture. A review was made of the current status of yabby culture in Australia and the present understanding of reproductive biology of decapod Crustacea. The review emphasised factors controlling several aspects of ovarian development, in particular the processes of vitellogenesis. The subsequent study was designed within the context of current hatchery practice and was based on existing knowledge of decapod reproduction, The sexual differentiation of the yabby after hatching was investigated by serial histological sections, and experiments were carried out to investigate the possibility of sex reversal of males. Most of this Investigation was concerned with removing the influence of the androgenic gland in directing male development, with the intent of observing the development of the elementary gonadal tissue into ovary. It was found that in contrast to other crustacean species, the sex of the yabby becomes fixed before the development of external secondary sexual characteristics, and before the androgenic gland can be discerned. Ovarian tissue developed in females at less than 8 weeks after hatching. A preliminary examination was undertaken for feminising parasites in gonadal tissue of a hermaphrodite yabby. Investigation of the ovary after spawning demonstrated that whilst the female was held under constant conditions of temperature and photoperiod, little rematuration occurred. Except for generation of previtellogenic oocytes during the first two days, the gonaciosomatic index remained low for up to 5 months after spawning. If the temperature of the female was reduced to 10°C and maintained constant, the previtellogenic oocytes were partially resorbed over a three week period. Rematuration then commenced, albeit at a low rate because of the reduced temperature, A method for standardising gonadosomatic indices was developed which took into account differences in hepatopancreatic nutrient reserves of individuals and loss of one or more appendages. This part of the study also considered constraints to rematuration and developed a method of accounting for differences in the ability of females to remature after spawning. Experiments were carried out to investigate the effect of crowding and temperature manipulation on initiating ovarian rematuration and to determine the rate of rematuration at 22°C once initiated. The duration of low temperature had no effect on rematuration; an overnight cooling was sufficient to initiate the process, Rematuration to the end of stage 2 vltellogenesis was substantially complete within 10 days. Crowding of females suppressed rematuration, but less than ideal water quality was not found to have any effect. The presence of a male initiated rematuration at a similar rate, but also led to stage 3 vitetlogenesis and spawning. A study was made of the pheromonal influence of the male through water borne factors without success. Rematuration could not be induced in ovigerous females. The literature review indicated that ovarian rematuration was under the control of an ovary stimulating hormone produced by the thoracic nerve ganglia. Attempts were therefore made to stimulate ovarian rematuration by incorporating the thoracic nerve into the diet of females. Attempts were also made to induce the release of ovary stimulating hormone from the thoracic nerve with 5-hydroxytryptamine, and also with octopamine. No effects were found, but a significant difference between the neurophysiology of the yabby and northern hemisphere crayfish was observed, and the implications of this finding are discussed. The study did not produce any conclusive evidence of an ovary stimulating hormone for the yabby. A model of ovarian rematuration which collects the findings of the experimental investigations was developed, and was used to suggest a hatchery broodstock management protocol. This model differs from existing models in that rematuration triggers and nutritional status are considered.
359

Molecular Characterisation of Structural Chromosomal Abnormalities Associated with Congenital Disorders

Mansouri, Mahmoud R. January 2006 (has links)
<p>Chromosomal abnormalities are defined as changes in the chromosome structure and fall in one of two categories. The first category is numerical alterations while the second category consists of structural abnormalities. Structural chromosomal abnormalities do not always interrupt genes in order to cause disease. They can also affect gene expression by separating a gene and its promoter element from distant regulatory elements. We have used characterisation of structural chromosomal abnormalities to identify the genetic bases for several congenital disorders.</p><p>In papers I-III, we have applied molecular characterisation of chromosomal translocations in order to identify candidate genes involved in mental retardation, hypospadias and anal malformation and premature ovarian failure. In paper I, we localised the chromosome X translocation breakpoint in a t(X;15) to be in the immediate proximity of the gene <i>ZDHHC15 </i>in a patient with severe mental retardation. Subsequent experiments revealed loss of <i>ZDHHC15</i> transcription in the patient which suggests this gene to be involved in the aetiology of the patient’s phenotype. In paper II, we show that a balanced translocation between chromosomes 6 and 17 in a patient with urogential malformation disrupts 2 genes, one at each translocation breakpoint. We also identified a fusion-gene as a result of the translocation. Our hypethesis is that the translocation together with its molecular consequences is important for the phenotype in the patient. Similarly, in paper III, we have used molecular characterisation of the breakpoints in a balanced translocation between chromosomes X and 11 in order to localise candidate genes in ovarian function. Our results indicate a number of genes affected by the translocation. In paper IV, we have used array-based comparative genomic hybridisation (array-CGH) in order to investigate a cohort of autistic sib-pairs for submicroscopic chromosomal alterations. We have identified several novel duplications and one novel deletion with strong association with autism.</p>
360

The regulation and role of hypoxia inducible factor-1 (HIF-1) in human cancer

Skinner, Heath Devin. January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains vi, 156 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

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