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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

Examining the Current U.S. Beef Trade Policies Concerning the Testing for Mad Cow Disease

Miller, David C 11 November 2004 (has links)
Despite existing mad cow disease surveillance efforts in the United States, in place since the 1980s, a cow that tested positive for mad cow disease was granted entrance into the U.S. in December, 2003. The cow that tested positive, according to witnesses, displayed no symptoms that are synonymous with advanced bovine spongiform encephalopathy, BSE. This occurrence had detrimental effects on the U.S. beef export market, as many countries banned American beef. Estimates of the damage inflicted reach into the billions of dollars. BSE in the U.S. has the potential of causing damages in other aspects as well. Aside from the fact that BSE is a public health issue, it has caused political rifts between nations, particularly between Canada and the U.S. It can undermine confidence in the USDA and confidence in the governments ability to handle emergencies. BSE can imperil American good that contain beef or beef products. Finally, it can undermine trust in scientists to provide useful guidance. The subtle changes in U.S. BSE surveillance efforts in the 1980’s were greatly surpassed by the changes that were made when a BSE-positive cow was discovered in Washington State in 2003. However, there remains room for much needed improvement in U.S. BSE surveillance efforts. These changes include: increased testing to include all cows slaughtered in the U.S. and all imported beef products, a nationwide animal tracking program, increased proficiency in training of inspectors, and the implementation of strict rules governing the ingredients of animal feed. The implementation of regulations based on economics instead of public health concerns has the potential to leave loopholes in regulations that the BSE agent might exploit. By enacting the recommendations made in this thesis, the U.S. will greatly increased its' odds of stopping the entrance and proliferation of BSE within its’ borders.
62

The first step towards the development of an electrophoretic prion detector

Madampage, Claudia Avis 02 September 2011
In nanopore analysis, peptides and proteins can be detected by the change in current when single molecules interact with an α-hemolysin pore embedded in a lipid membrane. Studies into the effects of fluorenylmethoxycarbonyl (Fmoc), acetylation or proline modification to negatively charged α-helical peptides showed that Fmoc peptides give more translocations than acetylated peptides. The addition of a proline in the middle of an acetylated peptide further reduces the number of translocations compared to Fmoc. The effect of peptide conformation on translocation or intercalation was studied with small α-helical and β-sheet hairpins. The capped β-hairpin increased translocations compared to the uncapped. The Fmoc-α-helical hairpin, containing a disulfide link, displayed both bumping and translocations whereas in the unlinked peptide the proportion of translocations was greater. Prion diseases arise from the misfolding and aggregation of the normal cellular prion protein. Nanopore analysis of prion peptides with α-helical and β-strand sequences show changes to the event parameters that help distinguish them. The interaction of bovine prion protein (bPrP), with α-hemolysin showed both bumping (type-I) and intercalation/translocation (type-II) events. There are several lines of evidence that indicate these type-II events with a blockade current of -65 pA for bPrP, represent translocations. Nanopore analysis showed that about 37% events were translocations. The interaction of metal ions with bPrP showed that Cu(II) or Zn(II) reduced translocations. Surprisingly, Mn(II) caused an increase in translocation events to about 64%. Complex formation between antibodies and prion peptides and proteins can be detected by nanopore analysis. The PrP/antibody complex is too large to translocate whereas the event parameters for unbound molecules are unchanged. In principle, a nanopore can detect a single molecule; thus, this work represents the first step towards the development of a prion detector. The nanopore will provide the sensitivity and the antibodies will provide the specificity to distinguish between PrPC and PrPSc. Also, the prion N- and C-terminal signal peptides interact with bPrP changing the event parameters, relating to a new mechanism. Finally, the folding intermediates of bPrP at 0.86 M Gdn-HCl suggests that the protein unfolds and then refolds into a different conformation with event parameters similar to those of bPrP.
63

The first step towards the development of an electrophoretic prion detector

Madampage, Claudia Avis 02 September 2011 (has links)
In nanopore analysis, peptides and proteins can be detected by the change in current when single molecules interact with an α-hemolysin pore embedded in a lipid membrane. Studies into the effects of fluorenylmethoxycarbonyl (Fmoc), acetylation or proline modification to negatively charged α-helical peptides showed that Fmoc peptides give more translocations than acetylated peptides. The addition of a proline in the middle of an acetylated peptide further reduces the number of translocations compared to Fmoc. The effect of peptide conformation on translocation or intercalation was studied with small α-helical and β-sheet hairpins. The capped β-hairpin increased translocations compared to the uncapped. The Fmoc-α-helical hairpin, containing a disulfide link, displayed both bumping and translocations whereas in the unlinked peptide the proportion of translocations was greater. Prion diseases arise from the misfolding and aggregation of the normal cellular prion protein. Nanopore analysis of prion peptides with α-helical and β-strand sequences show changes to the event parameters that help distinguish them. The interaction of bovine prion protein (bPrP), with α-hemolysin showed both bumping (type-I) and intercalation/translocation (type-II) events. There are several lines of evidence that indicate these type-II events with a blockade current of -65 pA for bPrP, represent translocations. Nanopore analysis showed that about 37% events were translocations. The interaction of metal ions with bPrP showed that Cu(II) or Zn(II) reduced translocations. Surprisingly, Mn(II) caused an increase in translocation events to about 64%. Complex formation between antibodies and prion peptides and proteins can be detected by nanopore analysis. The PrP/antibody complex is too large to translocate whereas the event parameters for unbound molecules are unchanged. In principle, a nanopore can detect a single molecule; thus, this work represents the first step towards the development of a prion detector. The nanopore will provide the sensitivity and the antibodies will provide the specificity to distinguish between PrPC and PrPSc. Also, the prion N- and C-terminal signal peptides interact with bPrP changing the event parameters, relating to a new mechanism. Finally, the folding intermediates of bPrP at 0.86 M Gdn-HCl suggests that the protein unfolds and then refolds into a different conformation with event parameters similar to those of bPrP.
64

Parent and Provider Decision-Making for Infants with HIE

Allen, Kimberly A. January 2012 (has links)
<p>Hypoxic ischemic encephalopathy (HIE) is a serious birth complication of full term infants; 40-60% of affected infants die by 2 years or have severe disabilities. Infants with HIE often have a normal gestation and parents anticipate a healthy birth. HIE can be managed with aggressively with moderate hypothermia < 6 hours of life, cardiopulmonary support, and seizure management. Experimental interventions such as moderate hypothermia > 6 hours of life and umbilical cord stem cell transplant are also available. Additional decision-making for these infants may include long-term developmental therapy, nutritional support, and respiratory support. However, who makes these decisions, what factors influence decision-making and the long-term impact of decision-making on parents and health care providers remains unknown. Therefore, the purpose of this study was to explore parental and health care provider decision-making for infants with HIE.</p><p>A longitudinal case study design was used to study 11 cases of infants with HIE. Each case included the infant, the parent, and the infant's providers. Infant medical record data, interviews and questionnaires were used to collect data from infant birth through 6 months of age. Content analysis was used to analyze the interviews. Descriptive statistics were used with the questionnaires. Visualization techniques were used to search for patterns and trends in the assembled data. </p><p>All infants required resuscitation and their treatment plans included aggressive care or aggressive and experimental care. The level of parental participation varied with in the first week of life depending on whether the infant was enrolled in experimental interventions plus aggressive care or only aggressive care. Parental hopefulness was lower in parents of infants who received experimental interventions, but the infants receiving experimental interventions were less critically ill than infants who received aggressive care only. Parental stress was also lower among parents of infants who received experimental interventions over the first 2 months of life. </p><p>Parents were concerned about the short and long-term impact of HIE, few parents understood that even though their infant had appropriate developmental outcomes at 6-months that did mean that neurological damage occurred. However in one case of an infant, the neurological development became central to the parental decision-making for the infant. Parents became less hopeful as diagnostic examinations continued find more complex conditions that were individually not problematic for the parents, but when the complexity of the infant's illnesses continued to unfold, parents feared that too many complications existed for their daughter to have an acceptable quality of life. Yet, when parents broached the topic of transitioning from aggressive care to palliative care with providers, they were told that withholding/withdrawing treatment was not appropriate for the infant. Not discussing withholding or withdrawing treatment ultimately created conflict between parents and providers due to differences in opinions about the predicted neurological outcomes for the infant. The conflict led to distrust and parents regretted most decisions they made for their infant. </p><p>Parental and provider decision-making is complex and many of the decisions within the 6-month trajectory were made within the first 6 hours of birth. Parents felt that the decision-making was appropriate in most cases, but the extent of the infant's injury remains unknown. How parents will evaluate the decision-making when the infant begins to miss developmental milestones is unknown. Results from this dissertation suggest that decision-making is a trajectory and decisions are not made in isolation. Implications for practice include discussing and educating parents during the first 6 months and later about developmental milestones and the importance of continuing therapy, even when the infant appears normal. Providers can also acknowledge to parents, up front, that the extent of the neurological injury is unknown and different providers may have different opinions about the long-term effects. By acknowledging these differences, providers can begin discussing the treatment options with parents and educating them about the specific needs of their infant.</p> / Dissertation
65

An input-output analysis of the economic impacts of chronic wasting disease and bovine spongiform encephalopathy in Alberta and Canada

Petigara, Milap Unknown Date
No description available.
66

Identification and Characterization of Pathogenic Mutations in Neurodevelopmental Disorders Discovered by Next-Generation Sequencing

Ruzzo, Elizabeth Kathryn January 2014 (has links)
<p>Neurodevelopmental disorders develop over time and are characterized by a wide variety of mental, behavioral, and physical phenotypes. The categorization of neurodevelopmental disorders encompasses a broad range of conditions including intellectual disability, autism spectrum disorder, attention deficit hyperactivity disorder, cerebral palsy, schizophrenia, bipolar disorder, and epilepsy, among others. Diagnostic classifications of neurodevelopmental disorders are complicated by comorbidities among these neurodevelopmental disorders, unidentified causal genes, and growing evidence of shared genetic risk factors. </p><p>We sought to identify the genetic underpinnings of a variety of neurodevelopmental disorders, with a particular emphasis on the epilepsies, by employing next&ndash;generation sequencing to thoroughly interrogate genetic variation in the human genome/exome. First, we investigated four families presenting with a seemingly identical and previously undescribed neurodevelopmental disorder characterized by congenital microcephaly, intellectual disability, progressive cerebral atrophy, and intractable seizures. These families all exhibited an apparent autosomal recessive pattern of inheritance. Second, we investigated a heterogeneous cohort of &sim;60 undiagnosed patients, the majority of whom suffered from severe neurodevelopmental disorders with a suspected genetic etiology. Third, we investigated 264 patients with epileptic encephalopathies &mdash; severe childhood epilepsy disorders &mdash; looking specifically at infantile spasms and Lennox&ndash;Gastaut syndrome. Finally, we investigated &sim;40 large multiplex epilepsy families with complex phenotypic constellations and unclear modes of inheritance. The studied neurodevelopmental disorders exhibited a range of genetic complexity, from clear Mendelian disorders to common complex disorders, resulting in varying degrees of success in the identification of clearly causal genetic variants. </p><p>In the first project, we successfully identified the disease&ndash;causing gene. We show that recessive mutations in <italic>ASNS </italic> (encoding asparagine synthetase) are responsible for this previously undescribed neurodevelopmental disorder. We also characterized the causal mutations <italic>in vitro</italic> and studied Asns&ndash;deficient mice that mimicked aspects of the patient phenotype. This work describes ASNS deficiency as a novel neurodevelopmental disorder, identifies three distinct causal mutations in the ASNS gene, and indicates that asparagine synthesis is essential for the proper development and function of the brain.</p><p>In the second project, we exome sequenced 62 undiagnosed patients and their unaffected biological parents (trios). By analyzing all identified variants that were annotated as putatively functional and observed as a novel genotype in the probands (not observed in the unaffected parents or controls), we obtained a genetic diagnosis for 32% (20/62) of these patients. Additionally, we identify strong candidate variants in 31% (13/42) of the undiagnosed cases. We also present additional analysis methods for moving beyond traditional screens, e.g., considering only securely implicated genes, or subjecting qualifying variants from any gene to two unique analysis approaches. This work adds to the growing evidence for the utility of diagnostic exome sequencing, increases patient sizes for rare neurodevelopmental disorders (enabling more detailed analyses of the phenotypic spectrum), and proposes novel analysis approaches which will likely become beneficial as the number of sequenced undiagnosed patients grows. </p><p>In the third project, we again employ a trio&ndash;based exome sequencing design to investigate the role of <italic>de novo</italic> mutations in two classical forms of epileptic encephalopathy. We find a significant excess of <italic>de novo</italic> mutations in the &sim;4,000 genes that are the most intolerant to functional genetic variation in the human population (P = 2.9 x 10<super>&ndash;3</super>, likelihood analysis). We provide clear statistical evidence for two novel genes associated with epileptic encephalopathy &mdash; <italic>GABRB3</italic> and <italic>ALG13</italic>. Together with the 15 well&ndash;established epileptic encephalopathy genes, we statistically confirm the association of an additional ten putative epileptic encephalopathy genes. We show that only &sim;12% of epileptic encephalopathy patients in our cohort are explained by <italic>de novo</italic> mutations in one of these 24 genes, highlighting the extreme locus heterogeneity of the epileptic encephalopathies. </p><p>Finally, we investigated multiplex epilepsy families to uncover novel epilepsy susceptibility factors. Candidate variants emerging from sequencing within discovery families were further assessed by cosegregation testing, variant association testing in a case&ndash;control cohort, and gene&ndash;based resequencing in a cohort of additional multiplex epilepsy families. Despite employing multiple approaches, we did not identify any clear genetic associations with epilepsy. This work has, however, identified a set of candidates that may include real risk factors for epilepsy; the most promising of these is the <italic>MYCBP2</italic> gene. This work emphasizes the extremely high locus and allelic heterogeneity of the epilepsies and demonstrates that very large sample sizes are needed to uncover novel genetic risk factors. </p><p>Collectively, this body of work has securely implicated three novel neurodevelopmental disease genes that inform the underlying pathology of these disorders. Furthermore, in the final three studies, this work has highlighted additional candidate variants and genes that may ultimately be validated as disease&ndash;causing as sample sizes increase.</p> / Dissertation
67

Selective increase of neuronal cyclooxygenase-2 (COX-2) expression in vulnerable brain regions of rats with experimental Wernicke's encephalopathy : effects of nimesulide

Gu, Baoying. January 2007 (has links)
Wernicke's encephalopathy is a neuropsychiatric disorder resulting from thiamine deficiency (TD) and is characterized by neuronal loss, astrocytic proliferation and microglial activation. Cyclooxygenases (COX) are enzymes which catalyze the first step in the synthesis of prostanoids. COX-1 is expressed constitutively and COX-2 is the inducible isoform. Groups of TD rats and pair-fed controls were killed at presymptomatic and symptomatic stages of encephalopathy. Cresyl violet and NeuN staining showed decreased numbers of neuronal cells in vulnerable regions (medial thalamus and inferior colliculus) but not in a spared region (frontal cortex). Numbers of GFAP-positive and OX-42-positive cells were increased at symptomatic stage of encephalopathy. Expression of COX-2 mRNA and neuronal COX-2 immunoreactivity were selectively increased in vulnerable regions of TD rats at symptomatic stages of encephalopathy. Nimesulide, a highly selective COX-2 inhibitor, lowered PGE2 levels and precipitated the progression of encephalopathy suggesting that COX-2 in this model is conferring neuroprotection.
68

An input-output analysis of the economic impacts of chronic wasting disease and bovine spongiform encephalopathy in Alberta and Canada

Petigara, Milap 06 1900 (has links)
This thesis utilizes input-output analysis to calculate the economic impacts from potential prion diseases outbreaks in Alberta and Canada. Both chronic wasting disease and bovine spongiform encephalopathy have the capacity to not only affect the farmed cervid and cattle industries, but to impact all industries with direct and indirect links to these sectors. Cervid sector shocks consistently yield small spillover effects on the economy in all models. In contrast, the cattle sector generates larger multiplier effects. A worst-case scenario that reduces cervid sector output to zero yields total economic losses of $11.5 million in Alberta, and $43.7 million in Canada. A reduction of cattle sector output to zero results in total economic losses of $6.4 billion in Alberta, and $34.9 billion in Canada. / Agricultural and Resource Economics
69

Mitochondrially inherited sensory ataxic neuropathy in golden retriever dogs : phenotype, clinical course and genotype of a novel neurological syndrome /

Hultin Jäderlund, Karin, January 2009 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2009. / Härtill 4 uppsatser.
70

Spinal cord pathology in chronic traumatic encephalopathy with motor neuron disease

Fry, Brian 22 January 2016 (has links)
Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease caused by repetitive head trauma and mild traumatic brain injuries (mTBIs) and has been associated with contact sports such as football, boxing, and ice hockey. CTE is a slowly progressing neurological disease that is often clinically associated with symptoms of memory loss, decline in cognitive function, behavioral changes such as increased impulsivity and aggression, and/or suicidal thoughts. Advanced stages of the disease present with more severe neurological changes such as dementia, speech and gait abnormalities, and parkinsonism. Amyotrophic Lateral Sclerosis (ALS, also known as Lou Gehrig Disease) is a progressive and fatal neurodegenerative disease characterized by motor neuron loss and corticospinal tract degeneration. While 90-95% of ALS cases are sporadic in nature, many genetic mutations have been identified that contribute to familial forms of the disease. The etiology of sporadic ALS is unknown but it is likely caused by a complex interaction of various genetic and environmental risk factors. Epidemiological evidence suggests that one such risk factor is brain trauma, the main risk factor associated with the development of CTE. In this study the spinal cord tissue of twelve athletes diagnosed with CTE who also developed a progressive motor neuron disease and showed symptoms of profound muscle weakness, atrophy, spasticity, and fasciculations several years before death was examined. The spinal cord tissue from these 12 CTE cases with motor neuron disease (CTE+MND) was compared to the spinal cord tissue of 10 sporadic ALS control cases. Results showed a difference in frequency of tau pathology between the two disease cohorts, as one-third of CTE+MND cases and none of the ALS cases showed tau immunoreactivity. In addition, TDP-43 immunoreactivity was present in every CTE+MND case but one and was present in all ALS cases. Motor neuron inclusions were positive for both FUS and p62 in both cohorts, and no distinct differences were observed cystatin C pathology. Overall, this suggests that the spinal cord inclusions in CTE+MND have a similar composition to sporadic ALS. However, there is an increased frequency of tau pathology in CTE+MND though this result did not reach statistical significance in this study.

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