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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.
161

Peripheral Dopamine 2 Receptors Both Modulate Central Dopamine Release and Adopt in a Similar Manner to that of Central Dopamine 2 Receptors

Obray, J. Daniel 24 April 2020 (has links)
Alcohol use disorder is a debilitating disorder affecting nearly 5% of people in the United States. Despite the prevalence of alcohol use disorder few affected individuals seek treatment and of those who do many will relapse. This highlights a need to develop new treatments for alcohol use disorder that are both more accessible and more effective. This dissertation characterizes a novel pathway involved in ethanol enhancement of dopamine levels in the nucleus accumbens as well as investigating alterations in dopamine 2 receptor expression and function following an acute dose of ethanol. This was done by using microdialysis to measure dopamine levels in the nucleus accumbens, single-unit recordings of dopamine neurons in the ventral tegmental area to measure dopamine neuron activity and place conditioning to measure the rewarding properties of the intravenous dopamine and ethanol. It was found that activation of peripheral dopamine 2 receptors by intravenous dopamine enhanced dopamine levels in the nucleus accumbens and dopamine neuron firing rate in the ventral tegmental area. Additionally, intravenous dopamine produced a modest conditioned place preference. Domperidone, a peripheral dopamine 2 receptor antagonist blocked each of these effects. Further, domperidone blocked ethanol enhancement of dopamine release in the nucleus accumbens and bidirectionally modulated the sedating effects of ethanol depending on the dose of ethanol administered. The involvement of peripheral dopamine 2 receptors in ethanol reward could not be ascertained in these studies as domperidone produced a weak conditioned place aversion. Finally, acute ethanol was found to enhance dopamine 2 receptor expression in the nucleus accumbens and medial prefrontal cortex while also enhancing dopamine 2 receptor expression on NK and B cells. Additionally, ethanol was found to reduce desensitization of dopamine 2 receptors in the ventral tegmental area. These results demonstrate that activation of peripheral dopamine 2 receptors can enhance dopamine levels in the nucleus accumbens and that this effect has relevance in understanding the effects of ethanol on dopamine release in the mesolimbic pathway. These results also provide evidence for transient upregulation of dopamine 2 receptors in the brain and on leukocytes suggesting that dopamine 2 receptor levels on leukocytes may be a useful biomarker for central dopamine function.
162

Peripheral Dopamine 2 Receptors Both Modulate Central Dopamine Release and Adopt in a Similar Manner to that of Central Dopamine 2 Receptors

Obray, J. Daniel 24 April 2020 (has links)
Alcohol use disorder is a debilitating disorder affecting nearly 5% of people in the United States. Despite the prevalence of alcohol use disorder few affected individuals seek treatment and of those who do many will relapse. This highlights a need to develop new treatments for alcohol use disorder that are both more accessible and more effective. This dissertation characterizes a novel pathway involved in ethanol enhancement of dopamine levels in the nucleus accumbens as well as investigating alterations in dopamine 2 receptor expression and function following an acute dose of ethanol. This was done by using microdialysis to measure dopamine levels in the nucleus accumbens, single-unit recordings of dopamine neurons in the ventral tegmental area to measure dopamine neuron activity and place conditioning to measure the rewarding properties of the intravenous dopamine and ethanol. It was found that activation of peripheral dopamine 2 receptors by intravenous dopamine enhanced dopamine levels in the nucleus accumbens and dopamine neuron firing rate in the ventral tegmental area. Additionally, intravenous dopamine produced a modest conditioned place preference. Domperidone, a peripheral dopamine 2 receptor antagonist blocked each of these effects. Further, domperidone blocked ethanol enhancement of dopamine release in the nucleus accumbens and bidirectionally modulated the sedating effects of ethanol depending on the dose of ethanol administered. The involvement of peripheral dopamine 2 receptors in ethanol reward could not be ascertained in these studies as domperidone produced a weak conditioned place aversion. Finally, acute ethanol was found to enhance dopamine 2 receptor expression in the nucleus accumbens and medial prefrontal cortex while also enhancing dopamine 2 receptor expression on NK and B cells. Additionally, ethanol was found to reduce desensitization of dopamine 2 receptors in the ventral tegmental area. These results demonstrate that activation of peripheral dopamine 2 receptors can enhance dopamine levels in the nucleus accumbens and that this effect has relevance in understanding the effects of ethanol on dopamine release in the mesolimbic pathway. These results also provide evidence for transient upregulation of dopamine 2 receptors in the brain and on leukocytes suggesting that dopamine 2 receptor levels on leukocytes may be a useful biomarker for central dopamine function.
163

The Effects of Diet, Population, and Water Temperature on the Stress Response of Angled Largemouth Bass Micropterus Salmoides

Dinken, Colin P 04 May 2018 (has links)
Angling practices subject Largemouth Bass Micropterus salmoides to multiple stressors, causing homeostatic physiological disturbances. The combined effects of ambient and live well temperature on stress responses from exercise have not been thoroughly examined. Large numbers of fish required for stress experiments can be produced by intensive culture, but hatchery fish may differ physiologically from wild fish due to dietary carbohydrates. Therefore, the effects of diet, population, and temperature on stress response and health were examined. Stress responses were similar among fish fed formulated and live diets and liver health improved within 4-6 weeks. Although cortisol responses of hatchery and wild fish differed, secondary stress responses were similar. Fish subjected to simulated angling at temperatures of 17, 25, 33 °C with live well temperature differentials of -4, 0, +4 °C, had the lowest resilience to stress at the warmest temperatures, exhausting energy supplies, coincident with metabolic acidosis and poor ion regulation.
164

Characterization of the expression and function of signaling lymphocyte activation molecule family members 9 in murine innate immune cells

Mikulin, Joseph A. 17 August 2022 (has links)
No description available.
165

The Interactions of Clostridium Perfringens With Phagocytic Cells

O'Brien, David Kenneth 24 April 2003 (has links)
Clostridium perfringens is the most common cause of gas gangrene (clostridial myonecrosis), a disease that begins when ischemic tissues become contaminated with C. perfringens. C. perfringens quickly multiplies in ischemic tissues and spreads to healthy areas, leading to high levels of morbidity and mortality. As a species, the bacterium can synthesize thirteen different toxins. The alpha toxin (PLC) and perfringolysin O (PFO) are thought to be important virulence factors in gangrene. We wished to understand how C. perfringens is capable of avoiding killing by the host immune system, and determine if PLC and PFO play a role in this avoidance. We found C. perfringens was not killed by J774-33 cells or mouse peritoneal macrophages under aerobic or anaerobic conditions. Using electron microscopy, we showed that C. perfringens could escape the phagosome of J774-33 and mouse peritoneal macrophages. We believe the ability of C. perfringens to survive in the presence of macrophages is due to its ability to escape the phagosome. Using a variety of inhibitors of specific receptors, we identified those used by J774-33 cells to phagocytose C. perfringens. The scavenger receptor, mannose receptor(s), and complement receptor (CR3) were involved in the phagocytosis of C. perfringens. To determine if PFO or PLC were involved in the ability of C. perfringens to survive in the presence of macrophages, we constructed C. perfringens strains lacking these toxins. The ability of C. perfringens to survive in the presence of J774-33 cells is dependent on PFO, while survival in mouse peritoneal macrophages is dependent on PFO and PLC. The ability of C. perfringens to escape the phagosome of J774-33 cells and mouse peritoneal macrophages is mediated by either PFO or PLC. Using a mouse model, we found that PFO and PLC were necessary for C. perfringens to survive in vivo using infectious doses 1000 times lower than those required to initiate a gangrene infection. We propose that PFO and PLC play a critical role in the survival of C. perfringens during the early stages of gangrene infections, when phagocytic cells are present and bacterial numbers are low. / Ph. D.
166

Messung L-Selektin-abhängiger Adhäsionsprozesse mit Hilfe eines homotypischen Aggregationsassays

Gratopp, Alexander 17 June 2000 (has links)
Ischemia followed by reperfusion, as happens in myocardial infarction, or the development of acute respiratory distress syndrome, are associated with a exaggerated extravasation of leukocytes into the surrounding tissue , which may cause severe bystander damage. In animal models of these diseases, pharmacological blockage of the leukocyte adhesion molecule, L-selectin (CD62L), has been shown to be partially protective by reduction or inhibition of leukocyte-mediated secondary tissue damage. The aim of this project was the development of an in vitro assay to investigate the relative effectiveness of potential L-selectin antagonists. Ideally, the assay should require low sample volumes and allow for measurements of larger series of reagents. The assay system investigated was based on the homotypic granulocyte aggregation under shear stress, which mimicks the L-selectin-dependent adhesion of leukocytes to previously arrested neutrophils on vascular endothelium. After optimizing numerous variables of the aggregation assay, the requirement of L-selectin for the homotypic granulocyte aggregation induced was demonstrated by inhibition experiments using soluble L-selectin or monoclonal antibodies directed against the lectin domain of L-selectin. Several carbohydrate polymers with L-selectin binding properties, such as the seaweed-derived fucose polymer fucoidin, high-molecular-weight dextran sulfate or heparin, also inhibited neutrophil aggregation in a dose-dependent fashion. However, despite employing a flow cytometry-based read-out technique, the assay remained extremely labor intensive, precluding investigations of extended series. Therefore, the homotypic aggregation experiments with freshly isolated human granulocytes remains a useful tool to further evaluate specific questions of L-selectin dependent adhesion processes, but it is not apt for transfer into routine laboratories.
167

Intestinal absorption of colostral leukocytes, peripheral blood mononuclear cells, and porcine umbilical cord matrix stem cells by neonatal pigs

Miller, Danielle January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Duane L. Davis / Intestinal absorption of colostral leukocytes (CL), peripheral blood mononuclear cells (PBMC), and porcine umbilical cord matrix stem cells (PUC) was analyzed in neonatal pigs. Maternal CL have previously been demonstrated in pigs, and maternal PBMC have been observed in calves to enter neonatal circulation after ingestion. PUC are primitive stem cells that are easily isolated from Wharton's jelly of the porcine umbilical cord. These cells do not have an immunogenic effect on the host upon initial transplantation. The general characteristics of PUC may allow them to serve as a delivery system to the neonate. Cellular migration through the duodenum, jejunum, and ileum was assessed using confocal microscopy. In vitro experiments utilized an organ explant culture system to determine the trafficking of labeled cells. Small-intestine tissue was collected from stillborn and sacrificed neonates. All three cell types (CL, PBMC, and PUC) were detected below the luminal surface, after 72 h of culture with media, and regardless of whether explants were from stillborns or live-born pigs. In vivo trafficking was assessed using neonatal pigs that were fed PBMC isolated from their mother or PUC from an unrelated pig. The effect of prior exposure to 25% acellular colostrum (AC) in medium was evaluated for both cell types. Piglets were euthanized 8 h or 24 h post feeding and sections of the small intestine collected. Both PBMC and PUC were found in all intestinal samples. Exposure to AC had no detected effect on the ability of either cell type to attach and migrate into the tissue. Labeled PUC were detected on the surface of the epithelium and in the lamina propria 8 h post treatment. PBMC were observed on the surface of the epithelium, in the lamina propria, and superficial submucosa 8 h following ingestion. In neonates sacrificed 24 h post treatment, both PUC and PBMC were observed on the surface of the epithelium, in the lamina propria, superficial submucosa, and deep submucosa of the small intestine. PUC and PBMC were noted at the apex, intermediate between the apex and the base, or at the base of the villus.
168

Porovnání tvorby cytokinů novorozeneckými leukocyty dětí zdravých a alergických matek. / Comparison of cytokine production by leukocytes from newborns of healthy and allergic mothers

Dusilová, Adéla January 2012 (has links)
The increasing incidence of children suffering from allergic diseases could be caused by sensitization of immature immune system during the intrauterine development. Several important scientific papers have demonstrated the ability of cord blood cells to respond by elevated proliferation activity after stimulation by common allergens. Following these findings, present study follows the production of cytokines which play a role in the pro- and anti-allergenic tuning of the immune system. Umbilical cord blood cells were stimulated with polyclonal activators (phytohaemagglutinin) and common allergens (ovalbumin, timothy grass, birch, mite). Subsequently, cytokine production was monitored using selected methods that reflect different stages of cell activation - at the level of mRNA by quantitative real time PCR (qRT-PCR), by flow cytometry detection of the presence of intracellular cytokines in different cell subpopulations and by ELISA measurement of cytokines in CBMC culture supernatants. The results obtained point to a very weak ability of these common allergens (timothy grass, birch, mite, ovalbumin) to stimulate CBMC to produce cytokines observed by all of these methodological procedures. Although we did not observe significant differences in CBMC cytokine production (IL-2, IL-4, IL-10, IL-12,...
169

"Efeito da poluição atmosférica urbana da cidade de São Paulo nas células sangüíneas e no sistema cardiopulmonar. Estudo morfo-funcional em camundongos in vivo" / Effect of urbain air pollution of Sao Paulo city in the blood and cardiopulmonary system : a morpho-functional study in mice in vivo

Matsumoto, Giselli Silva 05 September 2005 (has links)
Objetivo: checar se poluentes do ar urbano de São Paulo induzem alterações sangüíneas e cardiopulmonares. MM: camundongos Balb/c foram expostos por 7, 14, 21, 30 e 45 dias em 3 câmaras: Limpa (controle), Intermediária (seletiva ao PM) e Suja (ar externo). Após exposição, os animais foram ventilados (FlexiVent) e coletados dados de mecânica pulmonar, sangue, coração e pulmão. Foram registrados PM, CO, SO2 e NO2 diários. Resultados: aos 21 e 45 dias coincidentes com picos de poluição houve aumento da resistência de via aérea (45d p=0,012), leucocitose (21d p < 0,001 e 45d p=0,039) e vasoconstricção pulmonar (21d p=0,034) nos animais da Câmara Suja, sem alteração de coronárias. Nenhum poluente excedeu limites de qualidade de ar / Objective: verify if air pollution of São Paulo city induces alterations in blood and cardiopulmonary systems. MM: Balb/c mice were exposed during 7, 14, 21, 30 and 45 days to 3 chambers: Clean (control), Intermediate (PM only) and Dirty (external air). After exposure, animals were ventilated (FlexiVent) and collected lung mechanics data and blood, heart and lung. PM, CO, SO2 e NO2 were measured daily. Results: on day 21 and 45, coincidently to peak of pollutions, there was proximal airway resistance increase (45d p=0.012), leukocytosis (21d p < 0.001 and 45d p=0.039) and vasoconstriction of peribronchiolar arterioles (21d p=0.034) in animals of Dirty Chamber with no alterations of coronaries. Neither pollutants exceeded the standard limits
170

Desenvolvimento de reagente liofilizado de glucoheptonato-estanho para marcação de leucócitos com Tecnécio-99m in vitro / Development of lyophilized kit of Tin-Glucoheptonate for in vitro labeling of leucocytes with 99mTc

Nascimento, Rosemeire Fagundes 24 August 2007 (has links)
O estudo de processos inflamatórios e infecciosos em Medicina Nuclear apresenta grande relevância para a clínica médica diagnostica. Enquanto em alguns casos o diagnóstico é óbvio, baseado na história clínica e exame físico do paciente, em outros é mais difícil, por serem assintomáticos ou por apresentarem sintomas não específicos. O diagnóstico precoce do processo inflamatório ou infeccioso permite tratamento rápido e também o impedimento de outras complicações. Além disto, a distinção entre inflamação e infecção é de extrema importância, bem como a provável localização. O uso de leucócitos radiomarcados, já estudados e aplicados em várias patologias, é o método de escolha para visualização de focos de infecção e inflamação. A cintilografia de leucócitos radiomarcados foi introduzida em 1976 por McAffe e Thakur e desde então é usada para diagnosticar diferentes patologias que envolvem infiltração leucocitária como distúrbios inflamatórios do intestino, infecção óssea ou prótese-vasculares entre outras. A marcação dos leucócitos in vitro pode ser realizada com 111In utilizando-se oxima ou tropolona como ligante ou com 99mTc, tendo a hexametilpropileno amino oxima (HMPAO) como ligante, resultando em um complexo lipofílico. A melhor disponibilidade, menor tempo de realização do exame, melhor propriedade física e menor dose de radiação para o paciente, resultou na preferência pelo agente HMPAO marcado com 99mTc, ao invés do 111In, para a maioria das indicações na maioria dos países. Entretanto, a marcação empregando o agente HMPAO apresenta como desvantagens a curta estabilidade do reagente marcado, as exigências relacionadas ao processo de marcação (tempo pós-eluição do 99mTc), além do custo elevado, pois se trata de produto importado. Este trabalho visou o desenvolvimento do reagente liofilizado de glucoheptonatoestanho para marcação de leucócitos com 99mTc in vitro pelo método de préestanização. A otimização da técnica de marcação foi realizada através da incubação dos leucócitos, isolados de sangue total, com diferentes volumes do reagente de glucoheptonato-estanho por diferentes tempos à 37°C (préestanização), com posterior marcação com 99mTc (185 MBq), incubados à temperatura ambiente por 20 minutos. O rendimento da marcação foi superior a 90% na condição ótima de marcação. O reagente liofilizado mostrou-se estável por mais de 90 dias. As imagens cintilográficas obtidas 1, 2 e 3 horas após a administração dos leucócitos radiomarcados em coelho New Zeland demonstraram a alta eficiência de marcação de processo inflamatório provocado a partir da administração local de terebentina. O método de marcação de leucócitos desenvolvido apresenta aplicação promissora na clínica médica, com proposta de redução de custo do procedimento, apesar de ser um procedimento mais demorado quando comparado ao procedimento que utiliza o quelante lipofílico de HMPAO. / The study and localization of inflammatory and infection process in Nuclear Medicine represents a relevant tool in diagnostic procedures. In same cases, the diagnostic is easy and based on anamnesis and clinical observation; in other cases, the patients are asymptomatic or present non specific symptoms that difficult the diagnostic. The early diagnostic of inflammatory or infectious process allow the early introduction of therapy and prevents complications. Farther, the differentiation between inflammation and infection is of extreme importance as well as the localization of the focus. The use of labeled leucocytes, studied and applied in much pathologies, is the method of choice for the visualization of inflammation and infection. The scintigraphy using labeled leucocytes was introduced at 1976 by McAffe and Thakur and since of this is used in the diagnostic of different pathologies related to leucocyte infiltration like intestinal inflammatory disease, bone or prosthetic-vascular infections. The in vitro labeling of leucocytes with 111In was performed using oxime or tropolone as ligand and with 99mTc using hexamethylpropylene amine oxime (HMPAO) as ligand, resulting in a lipophilic complex. The 99mTc-HMPAG complex was preferably employed in many indications and countries do to the ideal physical properties of 99mTc that results in low dose to the patient. However, the labeling employing the HMPAO complex results in some disadvantages like the low stability of the complex, and some requirements related to the 99mTc elution (like the time pos elution), beyond the high cost of the compound that is imported. The aim of this work was the development of a tin-glucoheptonate lyophilized kit for in vitro leucocytes labeling with 99mTc using the pre-stannization method. The optimization of the labeling technique was developed using leucocytes isolated from total blood and employing different volumes of the tinglucoheptonate reagent and different incubation times at 37 deg C (pre-stannization), and posterior labeling with 99mTc (185 MBq), after 20 minutes reaction at room temperature. The labeling yield was superior to 90% using the optimized labeling conditions. Lyophilized reagent was stable after 90 days. Scintilographic images obtained 1, 2 e 3 hours after the administration of labeled leucocytes in New Zealand rabbit, showed good uptake on inflammatory focus promoted by tupertine injection. The leucocytes labeling method developed can be probably applied in clinical procedures and represents cost effective method in substitution of the lipophilic complex of HMPAO.

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