2011 MU theses - Access restricted to UM
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Item The role of astrocytic calcium signaling in brain damage after photothrombosis(University of Missouri--Columbia, 2011) Xie, Yicheng; Ding, Shinghua[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Ischemic stroke is the third leading cause of death in industrialized countries. Our previous study found elevated [Ca[superscript 2+]]i signals in astrocytes after photothrombosis-induced ischemia. However, the role of astrocytic Ca[superscript 2+] signaling in ischemia is still poorly understood. In this study, we generated a stable and repeatable photothrombosis-induced ischemia model so that its ischemic infarction could be controlled by regulating the intensity of the output light and the size of the irradiated area in the cortex, which could be used to study the mechanisms of tissue damage and neuronal protection. Secondly, we investigated the effect of the Pleckstrin Homology (PH) domain of Phospholipase C (PLC)-like protein p130 (p130PH) on Ca[superscript 2+] signaling in astrocytes in vivo. We used the serotype 2/5 recombinant adeno-associated virus (rAV2/5) vectors to introduce p130PH fused with a tagged protein monomer red fluorescent protein at the N-terminal (i.e., transgene mRFP-p130PH). In order to selectively disrupt the Ca[superscript 2+] signaling pathway in astrocytes, the transgene was driven by a novel astrocyte-specific promoter gfaABC1D. Our results show that mRFP-p130PH is exclusively expressed in astrocytes with a high efficiency and a stable expression level. In vivo imaging using two-photon microscopy demonstrated reduced Ca[superscript 2+] signal in transduced astrocytes in response to ATP simulation. As Ca[superscript 2+] signaling is a characteristic form of cellular excitability in astrocytes that can mediate chemical transmitter release and contribute to neuronal excitotoxicity, the current study provides an in vivo approach to better understand Ca[superscript 2+]-dependent gliotransmission and its involvement in glia related diseases (i.e., ischemia). In order to study the role of astrocytic Ca[superscript 2+] signaling in ischemia, we tested the photothrombosis ischemic model on IP[subscript 3]R2 knockout mice. First, we demonstrated that IP[subscript 3]R2 knockout mice depleted astrocytic IP[subscript 3]R in vivo, but also abolished IP[subscript 3] mediated astrocytic [Ca[superscript 2+]]i signaling in response to ATP using in vivo imaging. Between WT and IP[subscript 3]R2 knockout mice, there is no difference in the number of astrocytes number and expression of specific astrocytic proteins which have been demonstrated to be crucial in ischemia damage. At 24 hours after photothrombosis-induced ischemia, we found a similar size of infarct volume and neuronal response between WT and IP[subscript 3]R2 knockout mice. The same phenomena were observed at 2 days and 7 days after ischemia. Until day 14 after ischemia, we discovered smaller infarct volume in IP[subscript 3]R2 knockout mice than WT mice, with more shrinking tissue around the ischemic core in the IP[subscript 3]R2 knockout mice. Further investigation demonstrated that the IP[subscript 3]R2 knockout mice have more severe glia scar formation and microglia activation during the time period between day 7 and 14. The neurogenesis study suggests that more migration of proliferating cells in IP[subscript 3]R2 knockout mice might result in dense and thick glia scar after 14 days ischemia. However, investigation should be done to test the process of migration. These observations suggest that IP3 mediated astrocytic Ca[superscript 2+] has an active role in ischemia recovery.Item The drunken self : the five-factor model as an organizational framework for charcterizing one's own drunkenness(University of Missouri--Columbia, 2011) Winograd, Rachel P.; Sher, Kenneth J.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This study evaluated the use of the Five-Factor Model (FFM) as an organizational framework for understanding self-perceptions of drunkenness (i.e. individual changes in mood, affect, and behavior associated with intoxication). Existing literature supports the use of the FFM personality dimensions (i.e. Neuroticism, Extraversion, Agreeableness, Intellect, and Conscientiousness) as a comprehensive representation of stable aspects of mood, affect, and behavior. This study investigated self-reported, mean-level changes from baseline personality (i.e. sober personality) to typical "drunken"� personality when under the influence of alcohol. Using cross-sectional data from an online survey of college student drinkers at a large, mid-western university, participants reported on their sober and drunk "personalities."� On average, individuals reported being substantially lower in conscientiousness and intellect when drunk, and moderately higher in extraversion, with small decreases in neuroticism and agreeableness (with variation in amount of these changes associated with participant sex and drinking patterns). Findings support for the use of the FFM as a framework for organizing self-reported drunken personality change.Item Buriscon regulated immune response in Drosophila melanogaster(University of Missouri--Columbia, 2011) Wang, Qian; Song, Qisheng[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Bursicon is a heterodimeric neurohormone which binds to the receptor LGR2 and regulates various aspects in cuticle sclerotization and wing expansion in diverse insect orders. However, it is still unknown why some neurosecretory cells store only one bursicon subunit, similarly, it is not fully understood the function of burs [alpha] or burs [beta] in the course of insect development. We found that each of bursicon subunit is sufficient to induce immune responses in Drosophila larvae. The expression of several antimicrobial peptide (AMP) genes is mediated by the bursicon induced proteolytic activation of NF-[superscript k]B transcription factor Relish. These results implicate the D. melanogaster neurohormone bursicon with the novel function of modulating innate immune response. They also partially explain the presence and function of a single bursicon subunit during immature stages of Drosophila. More generally, our data suggest that bursicon plays a similar role in the post-edysial periods of other insect species.Item An evaluation of technical efficiency of small farm households Chuong My district, Ha Tay province, Vietnam(University of Missouri--Columbia, 2011) Vu, Yen Hoang; Meyers, William H. (William Henry), 1941-[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The research focused on technical efficiency in small farm households in Chuong My District- Ha Tay Province in Vietnam. The goal was to find the technical efficiency, allocative efficiency, scale efficiency and scope efficiencies among farms, as well as to investigate how farm characteristics might affect farm efficiencies. Vietnam was selected as the region of study because there is not much study on technical efficiency in this area, especially there is none study about how added enterprises or level of diversification impacts farm efficiencies. The dataset is obtained from two surveys: one was conducted in 2010, and the other was the 2006 Vietnam household livelihood survey. The first survey has 75 respondents, and the second has 81 respondents. The data envelopment analysis (DEA) approach is used to measure technical efficiency, and Tobit regression is used to see how the level of diversification and other farm characteristics affect the farm's efficiency. The results show that 2010 farms have higher technical efficiency than 2006 farms. Farmers who get higher profit also have higher technical efficiency and other efficiencies. According to regression results, among farm characteristics, age, off-farm income, education, loan, land and added enterprises have the most effect on farm's efficiencies.Item The interaction of positive and negative outcome expectancies on drinking: a latent growth modeling approach(University of Missouri--Columbia, 2011) Vergés, Alvaro; Sher, Kenneth J.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Despite the fact that a number of studies on expectancies have included measures of positive and negative expectancies, only a few have tested the interaction between them. Such interactions would be expected to be important because they might help identify patterns of expectancy configuration that indicate increased risk of heavy alcohol use. Moreover, to date no study has tested the interaction between positive and negative expectancies as they change over time. The current study was intended to fill this gap in the literature by estimating the interactions between initial levels as well as rates of change of positive and negative expectancies predicting alcohol consumption. Latent growth models were estimated across five stages of complexity using longitudinal data from 3,720 college students assessed during four consecutive years. Results showed that both positive and negative expectancies had significant associations with drinking, predicting both initial status and rates of change in alcohol use over time. Furthermore, the interaction between positive and negative expectancies predicted the rates of change in drinking levels both cross-sectionally and prospectively. These results suggest that individuals who exhibit higher increases in positive and negative expectancies might be at higher risk of increasing their levels of alcohol use during young adulthood.