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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.
1

A retrospective analysis of comorbid traits affecting feeding in infants with Down syndrome

Duvall, Nichole L. 03 July 2012 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Down syndrome (DS) is the most common aneuploidy to affect humans and occurs in approximately 1 of 750 live births. Individuals with DS present with a wide range of clinical phenotypes. Common craniofacial phenotypic expressions include a small mandible, protruding tongue, and a flattened nasal bridge. These traits may affect the feeding, breathing, and swallowing of individuals with DS. Because some complications may go unnoticed for longer periods of time, we hypothesize that significant cardiac and GI defects may be indicative of feeding and airway difficulties. In order to better understand the secondary phenotypes resulting from DS, we have implemented a retrospective chart review of 137 infants between zero and six months of age who were evaluated through the Down Syndrome Program at Riley Hospital for Children from August 2005 to August 2008. Data regarding cardiac, gastrointestinal, endocrine, airway, auditory, and feeding abnormalities have been collected and incedences and comorbidites of these traits has been examined. Comprehensive results indicate cardiac abnormalities occur in 80% of infants, 60% experience gastrointestinal complications, feeding difficulties occur in 46%, and airway complications occur in 38% of infants. Infants with DS were found to be breastfed less over time, with an increase in tube feeds. Notably, we have found all infants with videofluoroscopic evaluations had some type of dysphagia. The presence of gastrointestinal abnormalities closely correlate with the need for tube feeds, and the comorbidity between GI anomalies and muscle tone appear to indicate the likelihood of feeding difficulties and need for altered feeding strategies. Comorbidities between feeding difficulties were nearly significant with cardiac defects and significant with GI abnormalities. Identification of such associations will help healthcare providers determine the best course of treatment and recommended feeding methodology for infants with DS. In order to utilize an in vitro model to study the craniofacial dysmorphologies seen in individuals with DS, cranial neural crest cells (NC) have been cultured. With these, we have begun to investigate the mechanisms behind a smaller trisomic mandibular precursor as compared to the euploid. With this in vitro model, we will be able to test proliferation, migration, and senescence of NC in a culture system.
2

Effect of Epigallocatechin-3-gallate on Skeletal and Cognitive Phenotypes in a Down Syndrome Mouse Model

Abeysekera, Irushi Shamalka January 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Down syndrome (DS), a genetic disorder that affects ~1 in 700 live births, is caused by trisomy of human chromosome 21 (Hsa21). Individuals with DS are affected by a wide spectrum of phenotypes which vary in severity and penetrance. However, cognitive and skeletal impairments can be commonly observed in all individuals with DS. To study these phenotypes, we utilized the Ts65Dn mouse model that carries three copies of approximately half the gene orthologs found on Hsa21 and exhibit similar phenotypes as observed in humans with DS. Individuals with DS and Ts65Dn mice have deficits in bone mineral density (BMD), bone architecture, bone strength, learning and memory. Over-expression of DYRK1A, a serine-threonine kinase encoded on Hsa21, has been linked to deficiencies in DS bone homeostasis and cognition. Epigallocatechin-3-gallate (EGCG), an aromatic polyphenol found in high concentrations in green tea, is a selective inhibitor of DYRK1A activity. Normalization of DYRK1A activity by EGCG therefore may have the potential to ameliorate skeletal and cognitive deficits. We hypothesized that supplements containing EGCG obtained from health food stores/ online vendors will not be as effective as EGCG from a chemical company in correcting bone deficits associated with DS. Our results suggest that EGCG improves the bone mineral density of trisomic femurs significantly better than the supplements while the EGCgNOW supplement from NOW FOODS improves trabecular and cortical bone structure. The results from HPLC analysis of supplements showed the presence of other catechins in EGCgNOW and degradation analysis revealed the rapid degradation of supplements. Therefore we hypothesize that the presence of EGCG degradation products and other green tea catechins in supplements may play a role in the differential skeletal effects we observed. We further hypothesized that a three week treatment of adolescent mice with EGCG will lead to an improvement in the learning and memory deficits that are observed in trisomic animals in comparison to control mice. However, our results indicate that three weeks of low-dose EGCG treatment during adolescence is insufficient to improve hippocampal dependent learning and memory deficits of Ts65Dn mice. The possibility remains that a higher dose of EGCG that begins at three weeks but lasts throughout the behavioral test period may result in improvement in learning and memory deficit of Ts65Dn mice.
3

Molecular and Cellular Mechanisms Leading to Similar Phenotypes in Down and Fetal Alcohol Syndromes

Solzak, Jeffrey Peter 22 August 2013 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Down syndrome (DS) and Fetal Alcohol Syndrome (FAS) are two leading causes of birth defects with phenotypes ranging from cognitive impairment to craniofacial abnormalities. While DS originates from the trisomy of human chromosome 21 and FAS from prenatal alcohol consumption, many of the defining characteristics for these two disorders are stunningly similar. A survey of the literature revealed over 20 similar craniofacial and structural deficits in both human and mouse models of DS and FAS. We hypothesized that the similar phenotypes observed are caused by disruptions in common molecular or cellular pathways during development. To test our hypothesis, we examined morphometric, genetic, and cellular phenotypes during development of our DS and FAS mouse models at embryonic days 9.5-10.5. Our preliminary evidence indicates that during early development, dysregulation of Dyrk1a and Rcan1, cardinal genes affecting craniofacial and neurological precursors of DS, are also dysregulated in embryonic FAS models. Furthermore, Caspase 3 was also found to have similar expression in DS and FAS craniofacial neural crest derived tissues such as the first branchial arch (BA1) and regions of the brain. This may explain a developmental deficit by means of apoptosis. We have also investigated the expression of pAkt, a protein shown to be affected in FAS models, in cells located within the craniofacial precursor of Ts65Dn. Recent research shows that Ttc3, a gene that is triplicated and shown to be overexpressed in the BA1 and neural tube of Ts65Dn, targets pAkt in the nucleus affecting important transcription factors regulating cell cycle and cell survival. While Akt has been shown to play a role in neuronal development, we hypothesize that it also affects similar cellular properties in craniofacial precursors during development. By comparing common genotypes and phenotypes of DS and FAS we may provide common mechanisms to target for potential treatments of both disorders. One of the least understood phenotypes of DS is their deficient immune system. Many individuals with DS have varying serious illnesses ranging from coeliac disease to respiratory infections that are a direct result of this immunodeficiency. Proteasomes are an integral part of a competent and efficient immune system. It has been observed that mice lacking immunoproteasomes present deficiencies in providing MHC class I peptides, proteins essential in identifying infections. A gene, Psmg1 (Dscr2), triplicated in both humans and in Ts65Dn mice, is known to act as a proteasome assembly chaperone for the 20S proteasome. We hypothesized that a dysregulation in this gene promotes a proteasome assembly aberration, impacting the efficiency of the DS immune system. To test this hypothesis we performed western blot analysis on specific precursor and processed β-subunits of the 20S proteasome in thymic tissue of adult Ts65Dn. While the β-subunits tested displayed no significant differences between trisomic and euploid mice we have provided further insight to the origins of immunodeficiency in DS.
4

Adapted dance- connecting mind, body and soul

Swinford, Rachel R. 29 January 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Using Heideggerian interpretive phenomenology, this study illuminates the lived experience of an adapted dance program for individuals with Down syndrome and their family members. The overall pattern from both dancers and family members was adapted dance: connecting mind, body and soul. The primary theme from dancer interpretations was expressing a mosaic of positive experiences, and the primary theme from family member interpretations was experiencing pride in their loved ones. The dance program provided dancers an opportunity to express their authentic self while experiencing moments of full embodiment in the connection of their mind, body and soul. While dancers experienced the connection of mind-body-soul, family members recognized the importance of this connection in their loved one. This research is instrumental in advocating for opportunities for individuals with Down syndrome to experience dance as a social, physical and intellectual activity that results in learning and increasing social interactions. The research findings from this study can support future initiatives for dance programs that may influence a population that has limited access to physical activity and dance. The study’s teaching strategies, dance activities, class procedures and sequences, and feedback techniques can be used by other professionals who teach individuals with intellectual disabilities.
5

Effect of Epigallocatechin-3-gallate on a pattern separation task and hippocampal neurogenesis in a mouse model of Down syndrome

Stringer, Megan Elizabeth January 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Down syndrome (DS) is caused by three copies of human chromosome 21 (Hsa21) and results in an array of phenotypes including intellectual disability. Ts65Dn mice, the most extensively studied DS model, have three copies of ~50% of the genes on Hsa21 and display many phenotypes associated with DS, including cognitive deficits. DYRK1A is found in three copies in humans with Trisomy 21 and in Ts65Dn mice, and is involved in a number of critical pathways including CNS development and osteoclastogenesis. Epigallocatechin-3-gallate (EGCG), the main polyphenol in green tea, inhibits Dyrk1a activity. We have shown that a three-week EGCG treatment (~10mg/kg/day) during adolescence normalizes skeletal abnormalities in Ts65Dn mice, yet the same dose did not rescue deficits in the Morris water maze spatial learning task (MWM) or novel object recognition (NOR). Others have reported that An EGCG dose of 2-3 mg per day (90mg/ml) improved hippocampal-dependent task deficits in Ts65Dn mice. The current study investigated deficits in a radial arm maze pattern separation task in Ts65Dn mice. Pattern separation requires differentiation between similar memories acquired during learning episodes; distinguishing between these similar memories is thought to depend on distinctive encoding in the hippocampus. Pattern separation has been linked to functional activity of newly generated granule cells in the dentate gyrus. Recent studies in Ts65Dn mice have reported significant reductions in adult hippocampal neurogenesis, and after EGCG treatment, enhanced hippocampal neurogenesis. Thus, it was hypothesized that Ts65Dn mice would be impaired in the pattern separation task, and that EGCG would alleviate the pattern separation deficits seen in trisomic mice, in association with increased adult hippocampal neurogenesis. At weaning, Ts65Dn mice and euploid littermates were randomly assigned to the water control, or EGCG [0.4 mg/mL], with both treatments yielding average daily intakes of ~50 mg/kg/day. Beginning on postnatal day 75, all mice were trained on a radial arm maze-delayed non-matching-to-place pattern separation task. Euploid mice performed significantly better over training than Ts65Dn mice, including better performance at each of the three separations. EGCG did not significantly alleviate the pattern separation deficits in Ts65Dn mice. After the behavioral testing commenced, animals were given ad libitum food access for five days, received a 100mg/kg injection of BrdU, and were perfused two hours later. Coronal sections through the dorsal hippocampus were processed for BrdU labeling, and cells were manually counted throughout the subgranular zone of the dentate gyrus. The euploid controls had significantly more BrdU labeled cells than Ts65Dn mice, however, EGCG does not appear to increase proliferation of the hippocampal neuroprogenitor cells. This is the first report of deficits in Ts65Dn mice on a pattern separation task. To the extent that pattern separation depends on the functional involvement of newly generated neurons in an adult dentate gyrus, this approach in Ts65Dn mice may help identify more targeted pharmacotherapies for cognitive deficits in individuals with DS.
6

The psychosocial outcomes of adult siblings of adults with autism and Down syndrome

Belkin, Teri 31 July 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Little is known regarding the psychosocial outcomes of adult siblings of adults with autism. Accordingly, the current study sought to: (1) illuminate factors that predict health-related quality of life, caregiver burden, and reported benefits in adult siblings of adults with autism, using a stress and coping framework and (2) compare outcomes of siblings of adults with autism (n = 31) to siblings of adults with Down syndrome (DS) (n = 54). For the within subject hypotheses, analyses were repeated within the DS group and an overall Disability group (n = 97). The Disability group consisted of participants in the Autism and Down syndrome groups plus twelve individuals in a mixed group of adult siblings of adults with DS who presented with co-morbid symptoms of autism. Variables were organized using The Adult Sibling Caregiver Conceptual Model (ASCCM) into three categories: antecedents (e.g., sibling relationship quality, problem behaviors of the disabled sibling), mediators (e.g., coping strategies, cognitive appraisal types), and psychosocial outcome variables (i.e., mental and physical health-related quality of life, caregiver burden, and reported benefits). For the within subject primary hypotheses, I posited a series of relationships between the antecedents and outcomes based on prior literature on demographic and individual difference predictors (e.g., siblings of adults with autism with fewer problem behaviors would have increased health-related quality of life [HRQOL], decreased caregiver burden, and increased reported benefits) and on stress and coping factors related to the burden of providing care for an individual with autism (e.g., greater use of avoidant coping strategies would be related to lower HRQOL, increased caregiver burden, and decreased reports of benefits). Exploratory hypotheses also were examined (e.g., being married would be associated with increased HRQOL, decreased burden, and increased reported benefits). The within-subject results indicated support for eight of the ten primary hypotheses and five of the six exploratory hypotheses when examined within at least one of the study groups: Autism, DS, or Disability. Overall, sibling caregivers, regardless of their sibling’s disability, reported more favorable psychosocial outcomes when demands were lower (e.g., less severe levels of problem behaviors, fewer autism symptoms exhibited by their disabled sibling, decreased additional pile-up stress), when resources were available to cope with stress (e.g., social support, respite care), and when healthy responses to stress were reported (e.g., use of emotion focused vs. avoidant coping strategies, use of challenge vs. threat appraisal types). Of note, reported benefits, which have rarely been examined in the autism literature, were strongly related to the quality of a sibling relationship across all study groups, and with the helpfulness of received services and perceived social support within the Autism group. The between subject hypotheses also were largely supported. As expected, compared to siblings of those with Down syndrome, siblings of those with autism demonstrated greater levels of caregiver burden and lower mental HRQOL. Moreover, there was a rank ordering in levels of caregiver burden across disability groups; siblings of adults with DS reported the lowest burden, siblings of adults with DS with symptoms of autism reported significantly higher levels of burden, and siblings of those with autism reported the most burden. The results imply that autism, either alone or co-morbid with another diagnosis, presents an increased risk of stress and caregiver burden, not only in parent caregivers, but also in sibling caregivers. Interestingly, there was also evidence for higher levels of stress related growth within the Autism group compared to the DS group. Future research will be needed to generalize the results of this study to broader samples of adult siblings while taking a life course perspective to assess changes in non-disabled siblings’ outcomes over time.

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