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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.
11

Diffusion tensor imaging of human brain development

Lebel, Catherine Unknown Date
No description available.
12

The physical and behavioral effects of embryonic ethanol exposure in Caenorhabitis elegans

Lin, Conny 05 1900 (has links)
In this thesis I used Caenorhabitis elegans as a model of Fetal Alcohol Spectrum Disorder (FASD) to study the physical and behavioral effects of ethanol exposure during embryonic development. Davis et al. (2008) found that ethanol exposure during larval development in C. elegans produced physical/developmental and behavioral effects; however, whether exposure during embryonic development might produce similar outcomes remained to be elucidated. Because the type and degree of effects caused by developmental ethanol exposure was dependent on the pattern of ethanol treatment, in the first part of the thesis I investigated the physical/developmental effects of embryonic exposure to various ethanol doses, exposure durations, onsets and frequencies. I found that exposure to >30% ethanol for an hour during embryonic development was necessary to lower hatch rate, delay reproductive onset, and reduce body size in C. elegans. Furthermore, exposure during early embryonic development caused a larger effect than exposure during later stages, and multiple exposures produced a worse outcome than a single exposure for a comparable duration. In the second part of the thesis, I investigated locomotory activities and habituation of adult C. elegans exposed to various patterns of embryonic ethanol treatment. I found that the rate of locomotion was altered differently by chronic and acute embryonic ethanol exposure, but I did not find any effect in short- or long-term habituation. In summary, I have characterized the pattern of embryonic ethanol exposure necessary to produce physical/developmental effects in C. elegans, and identified the types of exposure conditions that would cause worse outcomes than others; in addition, I have found that embryonic ethanol exposure affects the rate of locomotion in C. elegans. In this thesis, I have established a foundation for the future investigation into the physical and motor defects caused by embryonic ethanol exposure in C. elegans. / Medicine, Faculty of / Graduate
13

Developmental ethanol exposure and its impact on behaviour and HPI axis activity of zebrafish

Baiamonte, Matteo January 2015 (has links)
Ethanol exposure during pregnancy is one of the leading causes of preventable birth defects, leading to a range of symptoms collectively known as fetal alcohol spectrum disorder (FASD). More moderate levels of prenatal ethanol exposure (PNE) lead to a range of behavioural deficits including aggression, poor social interaction, poor cognitive performance and increased likelihood of addiction in later life. Current theories suggest that adaptation in the hypothalamic-pituitaryadrenal (HPA) axis and neuroendocrine systems contributes to mood alterations underlying behavioural deficits and vulnerability to addiction. This has led to the suggestion that corticotrophin-releasing factor (CRF) antagonists and glucocorticoid (steroid) inhibitors may be potential therapeutics to address the deficits of PNE and for the treatment of addiction. The zebrafish (Danio rerio) has several advantages over mammalian models, such as low cost of maintenance, short life cycle, easy embryological manipulation and the possibility of large-scale genetic screening. By using this model, our aim is to determine whether developmental ethanol exposure provokes changes in the HPA axis (HPI axis in fish), as it does in mammalian models, therefore opening the possibilities of using zebrafish to elucidate the mechanisms involved, and to test novel therapeutics to alleviate deleterious symptoms. Thus this thesis focuses solely on the effect of developmental ethanol exposure on the functioning of the HPI axis in zebrafish. Stress-reactivity in zebrafish larvae ethanol-treated 1-9 days post 4 fertilisation (dpf) was assessed using thigmotaxis and thigmotaxis following airstress. In both tests, lower stress-related responses were obtained with ethanol treated animals, in that they spent less time at the edges of the apparatus (P<0.01, n=3). They also showed lower total body cortisol (P=0.04, n=14). Larvae also showed the same behaviour pattern two weeks after ethanol exposure, (23dpf) (P=0.04, n=3), again with reduced total cortisol (P=0.03, n=4). HPI-related gene transcription was also assessed in 9dpf ethanol treated zebrafish larvae, by qRT-PCR. Revealing up-regulation of CRH, CRHBP and CRHR2, normalized against β-Actin, Elav1 and Gap43 housekeeping genes. In situ hybridization revealed no spatial changes in CRH, CRH-BP and POMC with animals at the same stage. Behavioural stress-reactivity differences in 6-months old adults that had been exposed developmentally to ethanol were assessed using novel tank diving and thigmotaxis. Both assays indicated a decrease in stress-like behaviour due to early ethanol exposure compared to controls (P<0.05, n=5 both). Finally, cortisol levels were assayed from 9dpf larvae and 6-month-old adults that had been treated with ethanol during early development showed a significant reduction in cortisol output when air-exposed stressed compared to controls (P=0.04, n=5). Conclusion: Early ethanol exposure produced significant changes in cortisol, HPI gene mRNA expression and stress-reactive behaviour in 9dpf animals. Changes in cortisol and behaviour were still detected in 6-months old adults, developmentally treated with ethanol, indicating that early ethanol exposure has permanent effects on the HPI axis. 5 As our data contradicts the findings in mammalian literature where early ethanol exposure increases stress-like behaviour in later life, it is also possible that more permanent effects of PNE in mammals may arise through maternal-offspring interactions, during and post gestation, such as breastfeeding and maternal grooming of the offspring, which are absent in the zebrafish model.
14

Foetal alcohol spectrum disorder: The development of guidelines to inform policy

Adebiyi, Babatope Oluwadamilare January 2019 (has links)
Philosophiae Doctor - PhD / Introduction: Maternal alcohol consumption during pregnancy can result to birth defects, which may be developmental, intellectual and physical. Fetal alcohol spectrum disorder (FASD) is a term used to describe an array of disorders related to alcohol consumption during pregnancy. FASD is a severe public health problem globally, with South Africa having the highest prevalence (29 to 290 per 1000 live births). What makes the FASD problem severe in the country is rife of maternal risk factors and widespread binge drinking during pregnancy. There is no policy specifically addressing FASD despite being pervasive in South Africa. Government programmes to prevent and manage FASD remain limited and fragmental across relevant departments. Herein, we aimed to conduct a multi-method study with a modified Delphi approach to developing a guideline to inform the development of a comprehensive and multi-sectoral policy for the prevention and management of FASD. Method and analysis: We used a modified version of the World Health Organization’s approach to guideline development in three phases. In phase 1, we conducted four different studies to design the initial guideline prototype. The studies include an in-depth interview with policymakers and a focus group with relevant service providers on policy requirements for FASD, a document review of policies on FASD and a scoping review of various interventions employed for the prevention and management of FASD. The second phase involved using the initially developed guideline prototype to engage with the local and international experts on FASD for improvement on the content. In the third phase, we refined the prototype using a modified Delphi approach. Framework method and content analysis were used to analyse the qualitative data while the Statistical Package for Social Science (SPSS) software was used to analyse the quantitative data.
15

Examining Different Levels of Prevention of Birth Defects and Fetal Alcohol Spectrum Disorder

Goh, Y. Ingrid 16 July 2009 (has links)
While all women hope to deliver a healthy baby, approximately 3-5% babies are affected by birth defects. Birth defects can occur naturally or be induced by teratogens. Alcohol is a known teratogen that causes fetal alcohol spectrum disorder (FASD), the most commonly known cause of neurobehavioural and neurodevelopmental deficits. Individuals affected with FASD are likely to be involved with or require additional assistance from healthcare, education, social services, and justice sectors. Due to this immense burden, effective prevention of FASD can have a major public impact. Prevention of FASD can occur at different levels: primary prevention (preventing alcohol-induced birth defects from occurring in the first place); secondary prevention (preventing alcohol-induced birth defects from developing or progressing); tertiary prevention (improving the outcome of individuals affected with FASD); and quaternary prevention (preventing another child from being affected with FASD). The objective of this thesis was to explore a multilevel birth defect and FASD prevention strategy. Primary prevention by was investigated by maternal multivitamin supplementation to optimize fetal growing conditions, as alcoholics are commonly deficient in nutrients. A meta-analysis of maternal multivitamin supplementation demonstrated a decreased risk for certain congenital anomalies and pediatric cancers. Secondary prevention was investigated by a randomized double-blinded placebo-controlled evaluating the ability of high doses of antioxidants (vitamin C and vitamin E) to mitigate the effects of prenatal alcohol exposure. The study was ceased due to safety concerns regarding high doses of vitamin C and vitamin E in preeclamptic studies. Tertiary prevention was investigated by anonymous meconium screening of babies of Grey-Bruce, Ontario residents delivering at or transferred to St. Joseph’s Health Care in London, Ontario. A 30% prevalence of fatty acid ethyl esters (FAEE) positive meconium was observed at this high-risk unit. Meconium screening is also a means of quaternary prevention since positive screens also identify mothers who were unable to stop consuming alcohol after 13 weeks of pregnancy, and therefore are at risk of delivering another child who is prenatally exposed to alcohol. The identification and engagement of these mothers into treatment programs constitutes primary prevention of FASD in subsequent pregnancies.
16

The role of folate status in formate metabolism and its relationship to antioxidant capacity during alcohol intoxication

Sokoro, AbdulRazaq Abubakar Hamud 22 August 2007
Alcohol abuse during pregnancy has been associated with Fetal Alcohol Spectrum Disorder (FASD). Research to date has focused on the role played by ethanol in the development of this disorder. In addition to ethanol, alcoholic drinks also contain methanol. Hence, consumption of alcohol can also lead to methanol accumulation. Methanol is metabolized to formaldehyde, which is then rapidly metabolized to formate, a toxic metabolite. Folate, a B-vitamin and antoxidant, is a cofactor in the metabolism of formate. This study assessed the relationship between formate and folate, formate kinetics in folate deficiency and, changes in antioxidant capacity during formate insult in folate deficiency. The findings of this study would lead to a better understanding of the role of formate in the development of the etiology of FASD and form the basis of future research. The relationship between formate and folate was investigated in intoxicated human female subjects, sober drug rehabilitating females and, pregnant women. A negative (inverse) relationship was observed between plasma formate and folate in pregnant sober women (correlation coefficient = -0.4989). Such a relationship, however, was not observed in whole blood in alcohol intoxicated (correlation coefficient = 0.0899) and detox women (correlation coefficient = 0.2382). Because of the health promoting ingredients in grain and fruit based alcoholic drinks, antioxidant B-vitamins were higher during intoxication while homocysteine levels were lower.<p>Formate kinetics during folate deficiency and changes in the body antioxidant capacity was investigated in folate deficient young swine. Folate deficiency altered formate kinetics leading to decreased systemic clearance (by approximately 2.3 fold), increased half-life (by 2.5 fold) and, consequently increased exposure (by 2.7 fold). Folate deficiency alone compromised antioxidant capacity. However, the combination of folate deficiency and formate insult further compromised antioxidant capacity.<p>In conclusion, methanol accumulates after alcohol intoxication, which can lead to formate build up in the body. During folate deficiency formate kinetics is altered leading to reduced formate clearance and increased exposure. Exposure to formate coupled to folate deficiency compromises antioxidant capacity, which can have deleterious effects on the fetus.
17

Towards self-forgiveness and self-worth : journeys of birth mothers of children with FASD.

Wood, Megan 21 September 2010
The purpose of this study was to come to a greater understanding of the experiences of birth mothers of children with FASD since the birth of their child. The principles of feminist research practice were utilized throughout in order to give a voice to the women who participated in the study. The research followed the general guidelines to conducting hermeneutic phenomenology outlined by van Manen (1990). Purposeful sampling was used to recruit four birth mothers of children with FASD who have been involved in the mothering of that child. Data was generated through three semi-structured interviews with each participant, including a hermeneutic interview in which the women participated in the process of interpretation. Data was analysed using selective, detailed and wholistic methods and through the process of writing and re-writing (van Manen, 1990).<p> The results focus on the social and emotional experiences of the women who participated in the study. The experience of being a birth mother of a child with FASD is represented in a discussion of four main themes: Living with the Past: Self-Forgiven, yet Always Present; Living with Others: Judgement and Understanding; Living with the Self: Unworthy and Unfit; and Living with Ambivalence: Mothering as a Birth Mother. The implications of this research in relation to the understanding of the experiences of birth mothers of children with FASD and potential supports are discussed.
18

Examining Different Levels of Prevention of Birth Defects and Fetal Alcohol Spectrum Disorder

Goh, Y. Ingrid 16 July 2009 (has links)
While all women hope to deliver a healthy baby, approximately 3-5% babies are affected by birth defects. Birth defects can occur naturally or be induced by teratogens. Alcohol is a known teratogen that causes fetal alcohol spectrum disorder (FASD), the most commonly known cause of neurobehavioural and neurodevelopmental deficits. Individuals affected with FASD are likely to be involved with or require additional assistance from healthcare, education, social services, and justice sectors. Due to this immense burden, effective prevention of FASD can have a major public impact. Prevention of FASD can occur at different levels: primary prevention (preventing alcohol-induced birth defects from occurring in the first place); secondary prevention (preventing alcohol-induced birth defects from developing or progressing); tertiary prevention (improving the outcome of individuals affected with FASD); and quaternary prevention (preventing another child from being affected with FASD). The objective of this thesis was to explore a multilevel birth defect and FASD prevention strategy. Primary prevention by was investigated by maternal multivitamin supplementation to optimize fetal growing conditions, as alcoholics are commonly deficient in nutrients. A meta-analysis of maternal multivitamin supplementation demonstrated a decreased risk for certain congenital anomalies and pediatric cancers. Secondary prevention was investigated by a randomized double-blinded placebo-controlled evaluating the ability of high doses of antioxidants (vitamin C and vitamin E) to mitigate the effects of prenatal alcohol exposure. The study was ceased due to safety concerns regarding high doses of vitamin C and vitamin E in preeclamptic studies. Tertiary prevention was investigated by anonymous meconium screening of babies of Grey-Bruce, Ontario residents delivering at or transferred to St. Joseph’s Health Care in London, Ontario. A 30% prevalence of fatty acid ethyl esters (FAEE) positive meconium was observed at this high-risk unit. Meconium screening is also a means of quaternary prevention since positive screens also identify mothers who were unable to stop consuming alcohol after 13 weeks of pregnancy, and therefore are at risk of delivering another child who is prenatally exposed to alcohol. The identification and engagement of these mothers into treatment programs constitutes primary prevention of FASD in subsequent pregnancies.
19

The role of folate status in formate metabolism and its relationship to antioxidant capacity during alcohol intoxication

Sokoro, AbdulRazaq Abubakar Hamud 22 August 2007 (has links)
Alcohol abuse during pregnancy has been associated with Fetal Alcohol Spectrum Disorder (FASD). Research to date has focused on the role played by ethanol in the development of this disorder. In addition to ethanol, alcoholic drinks also contain methanol. Hence, consumption of alcohol can also lead to methanol accumulation. Methanol is metabolized to formaldehyde, which is then rapidly metabolized to formate, a toxic metabolite. Folate, a B-vitamin and antoxidant, is a cofactor in the metabolism of formate. This study assessed the relationship between formate and folate, formate kinetics in folate deficiency and, changes in antioxidant capacity during formate insult in folate deficiency. The findings of this study would lead to a better understanding of the role of formate in the development of the etiology of FASD and form the basis of future research. The relationship between formate and folate was investigated in intoxicated human female subjects, sober drug rehabilitating females and, pregnant women. A negative (inverse) relationship was observed between plasma formate and folate in pregnant sober women (correlation coefficient = -0.4989). Such a relationship, however, was not observed in whole blood in alcohol intoxicated (correlation coefficient = 0.0899) and detox women (correlation coefficient = 0.2382). Because of the health promoting ingredients in grain and fruit based alcoholic drinks, antioxidant B-vitamins were higher during intoxication while homocysteine levels were lower.<p>Formate kinetics during folate deficiency and changes in the body antioxidant capacity was investigated in folate deficient young swine. Folate deficiency altered formate kinetics leading to decreased systemic clearance (by approximately 2.3 fold), increased half-life (by 2.5 fold) and, consequently increased exposure (by 2.7 fold). Folate deficiency alone compromised antioxidant capacity. However, the combination of folate deficiency and formate insult further compromised antioxidant capacity.<p>In conclusion, methanol accumulates after alcohol intoxication, which can lead to formate build up in the body. During folate deficiency formate kinetics is altered leading to reduced formate clearance and increased exposure. Exposure to formate coupled to folate deficiency compromises antioxidant capacity, which can have deleterious effects on the fetus.
20

Towards self-forgiveness and self-worth : journeys of birth mothers of children with FASD.

Wood, Megan 21 September 2010 (has links)
The purpose of this study was to come to a greater understanding of the experiences of birth mothers of children with FASD since the birth of their child. The principles of feminist research practice were utilized throughout in order to give a voice to the women who participated in the study. The research followed the general guidelines to conducting hermeneutic phenomenology outlined by van Manen (1990). Purposeful sampling was used to recruit four birth mothers of children with FASD who have been involved in the mothering of that child. Data was generated through three semi-structured interviews with each participant, including a hermeneutic interview in which the women participated in the process of interpretation. Data was analysed using selective, detailed and wholistic methods and through the process of writing and re-writing (van Manen, 1990).<p> The results focus on the social and emotional experiences of the women who participated in the study. The experience of being a birth mother of a child with FASD is represented in a discussion of four main themes: Living with the Past: Self-Forgiven, yet Always Present; Living with Others: Judgement and Understanding; Living with the Self: Unworthy and Unfit; and Living with Ambivalence: Mothering as a Birth Mother. The implications of this research in relation to the understanding of the experiences of birth mothers of children with FASD and potential supports are discussed.

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