You limited your search to:

  Access Rights: Use restricted to UNT Community
  Partner: UNT Libraries
 Degree Discipline: Biology
 Collection: UNT Theses and Dissertations
Primary Cilia in the Oligodendrocyte Lineage

Primary Cilia in the Oligodendrocyte Lineage

Access: Use of this item is restricted to the UNT Community.
Date: May 2013
Creator: Hao, Yung-Chia
Description: oligodendrocytes migrate from the corpus callosum into the overlying cortex. The incidence of cilia did not change markedly across age groups, and did not vary consistently with the number of processes per cell, which was used as an indication of the maturation stage of OPCs and young OLs. The mean percent of Olig1 immunopositive (Olig1+) cells having cilia across ages was 33.1% + 16.5%, with all ages combined. In O4+ cells of these mice, 56.7 + 3.6% had primary cilia. If it is the case that adult OLs do not have cilia, the point in the lineage when primary cilia are lost is still unknown. Adult mice that had been injected with cyclopamine to block cilia-dependent Shh signaling were examined to determine whether the rate of generating new OPCs was influenced. In the CC of control mice, the numerical density of Olig1+/BrdU+ cells was 1.29 + 0.07/mm2 was reduced to 0.68 + 0.38/mm2 in the cyclopamine-injected group, and the numerical density of all BrdU+ cells (including both Olig1+ and Olig1- cells) of 4.55 + 1.50/mm2 in the control group was reduced to 3.14 + 1.27/mm2 in the cyclopamine-injected group. However, there were only 2 mice in each group and the ...
Contributing Partner: UNT Libraries
Tests of a New Model of Paclitaxel-Induced Neuropathy and the Effects of Paclitaxel on the Dorsal Root Ganglia

Tests of a New Model of Paclitaxel-Induced Neuropathy and the Effects of Paclitaxel on the Dorsal Root Ganglia

Access: Use of this item is restricted to the UNT Community.
Date: August 2011
Creator: McWilliams, Steven P.
Description: This study examined a new model of paclitaxel-induced neuropathic pain and the effects of systemic paclitaxel on the gap junction protein subunit Cx43 and potassium inwardly-rectifying channel Kir4.1 within the dorsal root ganglia. In the new neuropathic pain model, subplantar injections of paclitaxel resulted in decreased conduction velocities of A-beta fiber compound action potentials in the sciatic (5.9%) and tibial nerves (6.8%) as well as in M (10.6%) and H (10.2%) waves. By using repeated recordings it was found that following paclitaxel injection, conduction velocities in the contralateral plantar nerve increased (9.2%). Systemic injections of paclitaxel resulted in reduced Kir4.1 immunolabeling in the dorsal root ganglia compared to vehicle injections. This reduction was observed in total labeling (32.4%) as well as in areas of intense labeling (28.7%). Reductions in overall Cx43 immunolabeling (25%) and area (25%) following systemic paclitaxel injections were not statistically significant. The results of these studies suggest that subplantar injections of paclitaxel can result in reduced peripheral nerve conduction velocities. The results also show that a unilateral neuropathy can result in contralateral changes in conduction velocities. The effects of paclitaxel on reducing Kir4.1 levels suggest that neuropathic pain caused by paclitaxel may share mechanisms in common with ...
Contributing Partner: UNT Libraries
Automated Low-cost Instrument for Measuring Total Column Ozone

Automated Low-cost Instrument for Measuring Total Column Ozone

Access: Use of this item is restricted to the UNT Community.
Date: May 2006
Creator: Nebgen, Gilbert Bernard
Description: Networks of ground-based and satellite borne instruments to measure ultraviolet (UV) sunlight and total column ozone have greatly contributed to an understanding of increased amounts of UV reaching the surface of the Earth caused by stratospheric ozone depletion. Increased UV radiation has important potential effects on human health, and agricultural and ecological systems. Observations from these networks make it possible to monitor total ozone decreases and to predict ozone recovery trends due to global efforts to curb the use of products releasing chemicals harmful to the ozone layer. Thus, continued and expanded global monitoring of ozone and UV is needed. However, existing automatic stratospheric ozone monitors are complex and expensive instruments. The main objective of this research was the development of a low-cost fully automated total column ozone monitoring instrument which, because of its affordability, will increase the number of instruments available for ground-based observations. The new instrument is based on a high-resolution fiber optic spectrometer, coupled with fiber optics that are precisely aimed by a pan and tilt positioning mechanism and with controlling programs written in commonly available software platforms which run on a personal computer. This project makes use of novel low-cost fiber optic spectrometer technology. A cost ...
Contributing Partner: UNT Libraries
Inherent Problems Associated with the Identification of Genes Responsible for Allowing  B. cepacia to Adhere to Human Lung Carcinoma A549 Cells

Inherent Problems Associated with the Identification of Genes Responsible for Allowing B. cepacia to Adhere to Human Lung Carcinoma A549 Cells

Access: Use of this item is restricted to the UNT Community.
Date: May 2001
Creator: Nesty, Gilda S.
Description: In this project a bacteria's ability to bind to human lung tissue was investigated. To carry out this study Pseudomonas aeruginosa, Eschericia coli and Burkholderia cepacia were used. B. cepacia served as the bacterium of interest. Isolating the gene which confers upon this bacterium the ability to bind to lung tissue was the main objective of this study. P. aeruginosa has been identified as being the bacteria most responsible for causing serious lung infections that can result in cystic fibrosis. This bacterium therefore served as the positive control in this study. On the contrary, E. coli does not possess this binding ability and served as the negative control. This paper gives a detailed outline of the different procedures necessary for the successful completion of this project. Firstly, a broad guideline of the important steps involved are explored. This is followed by a discussion on potential problems and possible solutions. Throughout the document, illustrations of expected results are indicated so as to further guide the researcher.
Contributing Partner: UNT Libraries
Animal contribution to human medicine

Animal contribution to human medicine

Access: Use of this item is restricted to the UNT Community.
Date: May 2001
Creator: Kvernes, Kayce
Description: The use of animal models in research has led to a fierce debate between animal rights activists and scientists. The former claim that little useful information is gained from animal studies and the suffering of animals does not preclude any treatments which may be used to treat human illnesses. Yet, research scientists claim that in vivo animal models are of absolute necessity to developing treatments and cures to disease. To determine the necessity of animal use, one must examine the models currently in research. Have the animal models for disorders such as cystic fibrosis and muscular dystrophy given scientists enough information to develop effective treatments? This paper will examine the role of animal subjects in several disease research protocols, as well as the applicability of the research.
Contributing Partner: UNT Libraries
Application of cultured neuronal networks for use as biological sensors in water toxicology and lipid signaling.

Application of cultured neuronal networks for use as biological sensors in water toxicology and lipid signaling.

Access: Use of this item is restricted to the UNT Community.
Date: August 2004
Creator: Dian, Emese Emöke
Description: This dissertation research explored the capabilities of neuronal networks grown on substrate integrated microelectrode arrays in vitro to be applied to toxicological research and lipid signaling. Chapter 1 details the effects of chlorine on neuronal network spontaneous electrical activity and pharmacological sensitivity. This study demonstrates that neuronal networks can maintain baseline spontaneous activity, and respond normally to pharmacological manipulations in the present of three times the chlorine present in drinking water. The findings suggest that neuronal networks may be used as biological sensors to monitor the quality of water and the presence of novel toxicants that cannot be detected by conventional sensors. Chapter 2 details the neuromodulatory effects of N-acylethanolamides (NAEs) on the spontaneous electrical activity of neuronal networks. NAEs are a group of lipids that can mimic the effects of marijuana and can be derived from a variety of plant sources including soy lecithin. The most prominent NAEs in soy lecithin, palmitoylethanolamide (PEA) and linoleoylethanolamide (LEA), were tested individually and were found to significantly inhibit neuronal spiking and bursting activity. These effects were potentiated by a mixture of NAEs as found in a HPLC enriched fraction from soy lecithin. Cannabinoid receptor-1 (CB1-R) antagonists and other cannabinoid pathway modulators indicated ...
Contributing Partner: UNT Libraries
Evaluation of virulence in wild type and pyrimidine auxotrophs of  Pseudomonas aeruginosa using the eukaryotic model system  Caenorhabditis elegans.

Evaluation of virulence in wild type and pyrimidine auxotrophs of Pseudomonas aeruginosa using the eukaryotic model system Caenorhabditis elegans.

Access: Use of this item is restricted to the UNT Community.
Date: August 2004
Creator: Anvari, Sara
Description: The human opportunistic pathogen, Pseudomonas aeruginosa PAO1, has been shown to kill the nematode Caenorhabditis elegans. C. elegans has been a valuable model for the study of bacterial pathogenesis, and has reinforced the notion that common virulence and host defense mechanisms exist. Recently, the pyrimidine pathway was shown to regulate virulence levels. Therefore, mutations in the pyrimidine pathway of PAO1 showed decrease virulence in the nematode. When starving the nematode, bacterial resistance was also shown to increase. It was hypothesized that starvation induced the DAF pathway, which regulates the transcription of genes involved with the antibacterial defense mechanism. Further research will be conducted to test this theory by performing RNAi experiments for the genes functioning in the antibacterial defense mechanism.
Contributing Partner: UNT Libraries
Chemotactic Response of Lumbricus terrestris Coelomocytes to Larval and Adult Stages of Rhabditis pellio

Chemotactic Response of Lumbricus terrestris Coelomocytes to Larval and Adult Stages of Rhabditis pellio

Access: Use of this item is restricted to the UNT Community.
Date: December 1999
Creator: Medrano, Jennifer Centurion
Description: Experiments were performed to assess the suitability of Rhabditis pellio, a nematode found in earthworms, as a challenge organism for use in development of a biomarker assay to determine the potential of chemicals to suppress the immunocompetence of the non-specific immune system. To accomplish this goal, information on the life cycle of R. pellio was determined; including effects of incubation time and temperature on growth rates; along with information on the immune response elicited in the earthworm, Lumbricus terrestris. Immune parameters measured were coelomocyte migration toward and attachment to R. pellio larvae and adults. Preliminary background information showed that R. pellio has potential as a challenge organism for development of a biomarker assay.
Contributing Partner: UNT Libraries
Evaluation of City of Denton Sub-Watershed by Benthic Macroinvertebrate Field Experimental Approach

Evaluation of City of Denton Sub-Watershed by Benthic Macroinvertebrate Field Experimental Approach

Access: Use of this item is restricted to the UNT Community.
Date: August 2006
Creator: Mahato, Mahendra
Description: In this study, two different field experiments were designed to assess the relative influence of urbanization on benthic communities. During spring and summer, four urban and one reference sites from Denton County, Texas were selected for benthic macroinvertebrate evaluation. Statistically significant differences in colonized benthic macroinvertebrate taxa on artificial substrates were observed among the four urban sites and the reference site. Oligochaetes and chironomids were the dominant taxa at all sites. Identification of chironomid larvae at the subfamily and genus level to detect differences between sites had higher statistical power than the evaluation based on total chironomids. At the reference site, Caenis, Cladotanytarsus, Orthocladius, and Ceratopogonidae were the dominant taxa, while the urban sites were dominated by Dero, Physella, Ancylidae, Chironomus, Dicrotendipes, Glyptotendipes, Polypedilum, Pseudochironomus, Stenochironomus, and Tanytarsus. These differences may have been dependent upon differences in hydrologic regime and water quality between sites. Significant differences (ANOVA, p < 0.01) in water quality parameters (alkalinity, hardness, nitrates, phosphates, chlorides, sulfates, calcium, magnesium, potassium, and triazine) were found among water samples collected from the reference and urban sites. During the transfer period, most of the Ephemeroptera and Trichoptera taxa and a few other taxa disappeared from artificial substrates that were colonized ...
Contributing Partner: UNT Libraries
A morphological study of the avian (Gallus domesticus) ductus arteriosi during hatching.

A morphological study of the avian (Gallus domesticus) ductus arteriosi during hatching.

Access: Use of this item is restricted to the UNT Community.
Date: May 2006
Creator: Belanger, Candace
Description: The ductus arteriosi (DA) are two blood vessels connecting the pulmonary arteries to the descending aorta in the avian embryo. Following hatching, the DA closes, separation of the systemic and pulmonary circulation. I present the morphological changes that occur in the chicken DA during prepipping, internal pipping, external pipping, and hatching. The avian DA consists of two distinct tissue types, a proximal and a distal portion. Histological examination shows developmental differences between the proximal and distal portions of the DA with regard to lumen occlusion, endothelial cells, smooth muscle and elastin. Endothelial cell proliferation begins to occur as early as external pipping, with the lumen almost completely occluded by the 3rd day of post-hatching life. Expression of vascular endothelial growth factor (VEGF) increases in avian endothelial cells during hatching. I provide a morphological timeline of changes in the DA as the chicken develops from embryo to hatchling.
Contributing Partner: UNT Libraries
FIRST PREV 1 2 3 NEXT LAST