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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.
281

TRENDS IN DENTAL CARE FOR INDIVIDUALS WITH ECTODERMAL DYSPLASIA

Edwards, Justin 27 April 2011 (has links)
Purpose: The specific aim of this study is to evaluate the trends in dental health care for individuals with ectodermal dysplasia. Methods: This was a cross sectional analysis of subjects recruited through the National Foundation of Ectodermal Dysplasia (NFED). From 1997 to 2000, individuals with ectodermal dysplasia or their caregiver (if the individuals were too young to selfreport) voluntarily completed questionnaires. The questionnaire consisted of 37 items consisting of demographics, ectodermal dysplasia diagnosis, access to dental care, level of dental utilization, and type of dental services received. Descriptive statistics were used in addition to ANOVA analyses to evaluate the changing trends in oral health care for individuals with ectodermal dysplasia. Results: Preliminary results indicate: 1) individuals with ectodermal dysplasia are being diagnosed earlier than in the past, 2) physicians are primary source of the initial diagnosis of ectodermal dysplasia, 3) children with ectodermal dysplasia are receiving prostheses earlier than in the past, and 4) access to care is problematic. Conclusion: Diagnosis and recognition of treatment needs are occurring at an earlier age and that an access to dental care for individuals with ectodermal dysplasia continues to be an issue.
282

Prenatal Alcohol Exposure Reduces Dendritic Spine Density across Sensory Cortices

Oppong, Francis 06 May 2011 (has links)
Dendritic spines are the major site of excitatory synapses in cortex, and factors that reduce dendritic spine numbers will produce serious cortical processing deficits, such as has been demonstrated for mental retardation and other psychiatric disorders. Prenatal alcohol exposure also has detrimental effects on brain development that lead to Fetal Alcohol Spectrum Disorder (FASD), which results in reduction of dendritic spine numbers in the hippocampus, prefrontal cortex and somatosensory cortex. FASD also is associated with temporal processing disorders involving sequential auditory stimuli that would be processed in auditory cortical areas. However, it is unknown if the reduction of spine density following prenatal alcohol exposure occurs at auditory cortex, or is generally reduced across the different sensory cortices. This present study examined that question. Young adult ferrets (176 days old, 1 male, 1 female), that were exposed to alcohol during the equivalent of third-trimester development, were used to prepare Golgi-Cox stained sections through primary auditory cortex (A1). Other cortical regions examined included primary somatosensory (S1), and higher-level multisensory cortices of lateral rostral suprasylvian (LRSS) and rostral posterior parietal (PPr) areas. Control values from normal animals (n=3) were derived from a previous study. The results of this present study demonstrated that, dendritic spine density was significantly (Student's t-test, P < 0.05) lower in the alcohol treated group than in normal controls in all the cortical regions examined. These data indicate that although reduced spine density in auditory cortex may underlie temporal processing disorders in FASD, pre-natal alcohol exposure has widespread consequences for sensory cortical processing in general.
283

Genetic Manipulation of the Relapsing Fever Spirochete Borrelia hermsii Permits Novel Investigation into the Role of Factor H Binding in Borrelial Virulence

Fine, Lindy 01 January 2011 (has links)
Borrelia hermsii, an etiologic agent of tick-borne relapsing fever, binds negative complement regulator factor H (FH) via its FhbA protein. Direct demonstration of the role of FhbA in the disease process has been hindered by the lack of genetic manipulation systems for the relapsing fever Borrelia. Here, we demonstrate successful generation of a B. hermsii strain YOR fhbA deletion mutant (Bh YORΔfhbA) that constitutively produces green fluorescent protein (GFP). Genetic manipulation did not affect growth rate or plasmid composition. Bh YORΔfhbA lost factor H-binding and C3b-inactivation capabilities, but retained resistance to killing in human serum and infectivity in mice. Stable production of GFP was demonstrated in vitro and in vivo. Collectively, these results suggest that B. hermsii employs an unidentified mechanism of complement evasion that is FH-independent and sufficient for persistence within the host. Additionally, this study represents a significant methodological advancement in the molecular characterization of relapsing fever spirochetes.
284

The Effect of Insulating K-Type Files on Accuracy and Reliability as Used in Two Electronic Apex Locators

Finkler, Timothy 06 May 2011 (has links)
The purpose of this in-vitro study is to compare the accuracy and reliability of a 3rd and 4th generation electronic apex locator (EAL) in locating the apical foramen when using insulated and non-insulated K files. Forty extracted human adult single-rooted teeth were coronally sectioned and placed in agar. EAL determined tooth length measurements were compared to actual tooth measurements. Comparisons to the standard measures used correlation and paired t-test. Preliminary comparisons of the groups used ANOVA to compare the means and the Brown-Forsythe test to compare variance. In the final analyses, the measurements were compared using a repeated-measures mixed-model multiway ANOVA that allowed for heterogeneous variance in the subgroups. Findings were that accuracy is not different due to insulation in the Root ZX group (p-value=0.50) but is improved in the Elements Diagnostic Unit group (p-value<.001). Reliability is nominally improved with insulation in both the Root ZX and Elements Diagnostic Unit.
285

Quantitative Genetic Methods to Dissect Heterogeneity in Complex Traits

Bigdeli, T. Bernard 05 January 2012 (has links)
Etiological models of complex disease are elusive[46, 33, 9], as are consistently replicable findings for major genetic susceptibility loci[54, 14, 15, 24]. Commonly-cited explanations invoke low-frequency genomic variation[41], allelic heterogeneity at susceptibility loci[33, 30], variable etiological trajectories[18, 17], and epistatic effects between multiple loci; these represent among the most methodologically-challenging issues in molecular genetic studies of complex traits. The response has been con- sistently reactionary—hypotheses regarding the relative contributions of known func- tional elements, or emphasizing a greater role of rare variation[46, 33] have undergone periodic revision, driving increasingly collaborative efforts to ascertain greater numbers of participants and which assay a rapidly-expanding catalogue of human genetic variation. Major deep-sequencing initiatives, such as the 1,000 Genomes Project, are currently identifying human polymorphic sites at frequencies previously unassailable and, not ten years after publication of the first major genome-wide association find- ings, re-sequencing has already begun to displace GWAS as the standard for genetic analysis of complex traits. With studies of complex disease primed for an unprecedented survey of human genetic variation, it is essential that human geneticists address several prominent, problematic aspects of this research. Realizations regarding the boundaries of human traits previously considered to be effectively disparate in presentation[44, 39, 35, 27, 25, 12, 4, 13], as well as profound insight into the extent of human genetic diversity[23, 22] are not without consequence. Whereas the resolution of fine-mapping studies have undergone persistent refinement, recent polygenic findings suggest a less discriminant basis of genetic liability, raising the question of what a given, unitary association finding actually represents. Furthermore, realistic expectations regarding the pattern of findings for a particular genetic factor between or even within populations remain unclear. Of interest herein are methodologies which exploit the finite extent of genomic variability within human populations to distinguish single-point and cumulative group differences in liability to complex traits, the range of allele frequencies for which common association tests are appropriate, and the relevant dimensionality of common genetic variation within ethnically-concordant but differentially ascertained populations. Using high-density SNP genotype data, we consider both hypothesis-driven and agnostic (genome-wide) approaches to association analysis, and address specific issues pertaining to empirical significance and the statistical properties of commonly- applied tests. Lastly, we demonstrate a novel perspective of genome-wide genetic “background” through exhaustive evaluation of fundamental, stochastic genetic processes in a sample of matched affected and unaffected siblings selected from high- density schizophrenia families.
286

Genetic Dissection of Behavioral and Neurogenomic Responses to Acute Ethanol

Wolen, Aaron 02 December 2001 (has links)
Individual differences in initial sensitivity to ethanol are strongly related to the heritable risk of alcoholism in humans. To elucidate key molecular networks that modulate ethanol sensitivity we performed a systems genetics analysis of ethanol-responsive gene expression in brain regions of the mesocorticolimbic reward circuit (prefrontal cortex, nucleus accumbens and ventral midbrain) across the BXD RI panel, a highly diverse family of isogenic mouse strains before and after treatment with ethanol. Acute ethanol altered the expression of ~2,750 genes in one or more regions and 400 transcripts were jointly modulated in all three. Ethanol-responsive gene networks were extracted with a powerful graph theoretical method that efficiently summarized ethanol's effects. These networks correlated with acute behavioral responses to ethanol and other drugs of abuse. As predicted, networks were heavily populated by genes controlling synaptic transmission and neuroplasticity. Several of the most densely interconnected network hubs, including Kcnma1 and Gsk3-beta, are known to influence behavioral or physiological responses to ethanol, validating our overall approach. Other major hub genes like Grm3 and Nrg3 represent novel targets of ethanol effects. Networks were under strong genetic control by variants that we mapped to a small number of chromosomal loci. Using a novel combination of genetic, bioinformatic and network-based approaches, we identified high priority cis-regulatory candidate genes, including Scn1b, Gria1, Sncb and Nell2. The ethanol-responsive gene networks identified here represent a previously uncharacterized intermediate phenotype between DNA variation and ethanol sensitivity in mice. Networks involved in synaptic transmission were strongly regulated by ethanol and could contribute to behavioral plasticity seen with chronic ethanol. Our novel finding that hub genes and a small number of loci exert major influence over the ethanol response of gene networks could have important implications for future studies regarding the mechanisms and treatment of alcohol use disorders.
287

Antinociceptive Effects of Monoamine Reuptake Inhibitors in Assays of Pain-Stimulated and Pain-Depressed Behaviors

Rosenberg, Marisa 30 March 2012 (has links)
ANTINOCICEPTIVE EFFECTS OF MONOAMINE REUPTAKE INHIBITORS IN ASSAYS OF PAIN-STIMULATED AND PAIN-DEPRESSED BEHAVIOR By Marisa B. Rosenberg A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University. Virginia Commonwealth University, 2012 Advisor: Sidney Stevens Negus, Ph.D. Professor, Department of Pharmacology/Toxicology Noxious stimuli can produce pain-related stimulation of some behaviors (e.g. withdrawal responses) and depression of other behaviors (e.g. feeding, locomotion, responding maintained by many types of positive reinforcement). Monoamine reuptake inhibitors are used clinically to treat depression and to manage some types of pain. This study examined the antinociceptive properties of a variety of monoamine reuptake inhibitors selective for SERT, NET and DAT in complementary assays of acute pain-stimulated and pain-depressed behaviors. Intraperitoneal injection of dilute lactic acid (1.8% in a volume of 1ml/kg) was used as a noxious stimulus to stimulate a stretching response and to depress intracranial self-stimulation (ICSS) of the median forebrain bundle. All eight monoamine reuptake inhibitors produced an antinociception-like blockade of acid-stimulated stretching, but only compounds with prominent DA reuptake inhibition (SDRIs RTI-113 and bupropion and the TRI RTI-112) were able to block acid-depressed ICSS, although these effects were produced only at doses that also produced an abuse-related facilitation of control ICSS. Selective or mixed-action inhibitors of 5-HT and NE failed to block acid-induced depression of ICSS. In a separate group of rats, citalopram was also tested using a repeated dosing regimen (10 mg/kg x 3 doses) shown previously to produce antidepressant effects in a forced-swim test in rats. As with acute administration, repeated citalopram decreased acid-stimulated stretching but failed to block acid-induced depression of ICSS. Taken together, these results suggest that SSRIs, SNRIs and S+NRIs produce relatively non-selective depression of all behavior rather than a selective blockade of sensory sensitivity to noxious stimuli. Conversely, dopamine reuptake may be able to block sensory detection of noxious stimuli. Additionally, these results suggest that assays of pain-depressed behavior can provide new insights on analgesia-related effects of monoamine reuptake inhibitors.
288

Therapeutic Drug Monitoring of Factor VIII Prophylaxis Using Its Plasma Coagulant Activity and Global Hemostasis Biomarkers: A Pharmacokinetic/Pharmacodynamic Pilot Study

Al, Hawaj Maitham 30 April 2012 (has links)
Background: The current clinical practice of factor VIII (FVIII) prophylaxis revolves around converting patients with severe hemophilia A, hereafter simply referred to as hemophilia, phenotype (defined as plasma factor VIII coagulant activity [FVIII:C] <1 IU dL-1) to moderate hemophilia phenotype (defined as plasma FVIII:C from 1–5 IU dL-1). However, a wide inter-individual variation in bleeding tendency is observed despite changes in plasma FVIII:C (pharmacokinetic [PK] changes). Therefore, monitoring FVIII prophylaxis by global hemostasis biomarkers (pharmacodynamic [PD] response) can potentially be beneficial. Objective: To conduct appropriate PK/PD modeling using plasma FVIII:C and global hemostasis (platelet function and blood viscoelastic) biomarkers in severe hemophilia. Methods: Nine non-bleeding severe hemophiliacs (plasma FVIII:C <1 IU dL-1) with variant bleeding tendency (5 frequent bleeders and 4 infrequent bleeders) were infused with a recombinant factor FVIII (rFVIII) prophylactic dose (mean = 32.1 international units per kilogram [IU kg-1]). Blood was collected at baseline and 0.5-, 1-, 2-, 4-, 8-, 12-, 24- and 48-hours (h) post-dose for plasma FVIII:C, platelet function (platelet contractile force [PCF], clot elastic modulus [CEM] and force onset time [FOT]) and blood viscoelastic (reaction-time [R], kinetics-time [K] and maximum amplitude [MA]) biomarkers and activated partial thromboplastin time (aPTT). Non-compartmental analysis (NCA) was performed using standard methods. Compartmental analysis (CA) and PK/PD modeling were performed by non-linear regression. Correlation and analysis of variance (ANOVA) were used to explore the role of clinically relevant modifiers of bleeding tendency, as appropriate. ANOVA was used to assess inter-group differences in pertinent PK and PD parameters. P value <0.05 significance level was pre-specified for all statistical tests. Results: Mean (±SD) volume of distribution at steady state (Vss), total clearance (CLtot) and terminal half-life (t1/2) from NCA were 40.5 (±11.2) milliliter per kilogram (mL kg-1), 2.9 (±1.2) milliliter per hour per kilogram (mL h-1 kg-1) and 11.6 (±6.2) h, respectively. Mean (±SD) Vss and CLtot from the one-compartment body model (CA) were 39.6 (±8.9) mL kg-1 and 3.1 (±1.3) mL h-1 kg-1, respectively. The mean (±SD) baseline effect (E0) and slope from the PK/PD linear modeling were: for aPTT, 48.9 (±4.4) seconds (sec) and -0.025 (±0.009) second deciliter per international unit (sec dL IU-1), respectively; for PCF, 0.3 (±0.3) kilodynes (kdynes) and 0.008 (±0.004) kilodynes deciliter per international unit (kdynes dL IU-1), respectively; and for CEM, 0.0 (±0.0) kilodynes per square centimeter (kdynes cm-2) and 0.032 (±0.016) kilodynes deciliter per international unit per square centimeter (kdynes dL IU-1 cm-2), respectively. The mean (±SD) maximum effect (Emax) and half the maximum effective concentration (EC50) from the PK/PD sigmoidal Emax model were: for FOT, 70.1 (±16.9) % reduction and 87.8 (±31.4) IU dL-1 for FOT, respectively; for R, 74.9 (±26.0) % reduction and 68.5 (±28.4) IU dL-1, respectively; and for K, 73.2 (±36.4) % reduction and 67.2 (±29.0) IU dL-1, respectively. MA was not PK/PD modeled due to its low sensitivity. Conclusions: Plasma FVIII:C remained ≥1 IU dL-1 over the prophylactic interval. FOT and R were the most sensitive biomarkers at lower plasma FVIII:C. PCF and CEM were more sensitive than K and aPTT at lower plasma FVIII:C. MA was the least sensitive biomarker. Correlation and inter-group differences did not reach statistical significance (small sample size). These results may be used to assess risk of bleeding and dose-optimize FVIII prophylaxis in severe hemophilia.
289

Fullerene C70 derivatives dampen anaphylaxis and allergic asthma pathogenesis in mice

Norton, Sarah 20 April 2012 (has links)
Fullerenes are carbon nanospheres that can be solublized by the addition of polar chemical groups to the carbon cage, forming fullerene derivatives. One specifically derivatized fullerene compound, termed C70-Tetragylocolate (C70-TGA), has been shown to stabilize mast cell responses in vitro thus we hypothesized it may have an effect on mast cell-driven diseases such as asthma and systemic anaphylaxis. To observe the effects of C70-TGA on systemic anaphylaxis, mice were subjected to a model of passive systemic anaphylaxis. In this model, mice were injected with DNP-specific IgE 16 hours prior to challenge, then treated with C70-TGA. Immediately prior to DNP challenge, mice were subjected to a second injection of C70-TGA. Following DNP challenge, body temperature was recorded and blood was collected for quantitation of histamine levels. Treatment with C70-TGA significantly reduced body temperature drop associated with systemic anaphylaxis and serum histamine levels. To observe the effects of C70-TGA on chronic features of asthma in vivo, we utilized a heavily MC influenced model of asthma pathogenesis. Mice were sensitized by intraperitoneal (i.p.) injection of ovalbumin (OVA) in saline, challenged intranasally (i.n.) with OVA, and one of two treatment strategies was pursued. In one, C70-TGA was given i.n. throughout disease development. In the other, C70-TGA was given following an initial set of challenges to allow disease to develop prior to treatment; mice were then re-challenged with OVA to assess the effect on established disease. We found that C70-TGA treatment significantly reduced airway inflammation and eosinophilia and dramatically reduced bronchoconstriction in either model. Cytokines IL-4 and IL-5 and serum IgE levels are significantly reduced in C70-TGA treated animals. Interestingly, we also saw an increase in the anti-inflammatory eicosanoid 11, 12-epoxyeicosatreinoic acid (11,12-EET) in the BAL fluid, suggesting the involvement of this mediator in C70-TGA inhibition. Further experiments utilizing an inhibitor of 11,12-EET formation (6-(2-Propargyloxyphenyl)hexanoic acid) and a structural analog of 14,15-EET (14,15-EE-5(Z)-E) in vivo indicate that these mediators are closely associated with C70-TGA mediated inhibition as their inhibition reverses the anti-inflammatory effects of C70-TGA. Importantly, mice did not exhibit any acute toxicity following C70-TGA treatment and liver and kidney function were normal. Collectively, these results show that the fullerene C70 derivative C70-TGA is capable of dampening severe allergic responses including systemic anaphylaxis, airway inflammation, and bronchoconstriction. The mechanism of inhibition is through the upregulation of the anti-inflammatory EETs, which may dampen mast cell degranulation in vivo, thus contributing to the inhibitory effect of C70-TGA on allergic disease.
290

TOWARDS UNDERSTANDING THE MECHANISM OF ACTION OF ABUSED CATHINONES

Vekariya, Rakesh 27 July 2012 (has links)
The dopamine transporter (DAT) mediates reuptake of dopamine from the synaptic cleft into the presynaptic terminus and plays a critical role in maintaining the normal function of dopaminergic neurons. DAT is the major target of widely abused psychostimulant drugs, including cocaine and amphetamine. DAT also figures into disease states, and it is a target for therapeutic drugs. It is known that cathinone and methcathinone, β-keto analogs of amphetamine and methamphetamine, respectively, produce pharmacological actions similar to amphetamine. Cathinone and methcathinone analogs are recently gaining in popularity on the clandestine market (e.g. ‘bath salts’). Cathinone and methcathinone analogs as well as their amphetamine and methamphetamine counterparts were synthesized and examined at the hDAT expressed in Xenopus oocytes. One of the two major constituents of ‘bath salts’ (i.e., mephedrone) produced an electrophysiological signature similar to the dopamine releasing agent S(+)-amphetamine while the other major constituent (i.e., MDPV) produced an electrophysiological signature similar to the dopamine re-uptake inhibitor cocaine.

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