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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

An investigation of the effect of Bifidobacterium infantis on hippocampal interleukin-6 levels in a rodent model of hypoxia-ischemia following preterm birth

Blaney, Caitlin 11 September 2016 (has links)
Inflammation has modulatory effects on the brain, particularly during development. These plastic changes can hold severe functional consequences. Perinatal hypoxia-ischemia (HI)-induced inflammation can result in cerebral palsy and cognitive impairment. In an attempt to reduce inflammation in the brain, we assessed the probiotic Bifidobacterium (B.) infantis as an HI intervention, using a rat model. Rat pups, developmentally equivalent to preterm infants, were exposed to chronic hypoxia from postnatal (PND) 3 –PND 10. Inflammation was assessed through hippocampal concentrations of the cytokine interleukin-6 (IL-6). Tissue was collected from pups on PND 10 and analyzed via enzyme-linked immunosorbent assay (ELISA). Results showed lower IL-6 concentrations in hypoxic groups , regardless of B. infantis administration. Qualitative observations suggested poor gut health in association with hypoxia and probiotic exposure. These preliminary findings support the chronic hypoxia exposure model of HI and suggest the association with IL-6 and HI events is less straightforward than expected. / October 2016
2

Response of the Femur to Exercise During Recovery Between Two Bouts of Hindlimb Unloading in Adult Male Rats

Gonzalez, Estela 2012 August 1900 (has links)
Mechanical unloading with microgravity exposure during spaceflight induces bone loss in weight bearing bones. Combined with loss of bone due to aging, this disuse bone loss puts astronauts at increased risk of fracture upon returning to 1G conditions. It is important to study countermeasures, such as exercise, to mitigate or prevent this bone loss. This study utilized the hindlimb unloaded (HU) rat model to characterize the effects of resistance exercise on recovery dynamics in-between two bouts of HU. In the larger project adult male Sprague-Dawley rats, six months of age, were divided into the following groups: baseline (sacrificed at 6 months of age); aging cage controls (did not undergo any treatment, sacrificed at 7, 8, 9, 10, and 12 months of age); 1HU7 (one month of HU at 6 months of age followed by three months of ambulatory recovery); 2HU10 (one month of HU at 6 months of age, ambulatory recovery for two months, one month HU at 9 months of age, and final two month ambulatory recovery); 1HU10 (one month HU at 9 months of age and two month ambulatory recovery); and 2HU+Ex (One month HU at 6 months of age, two month resistance exercise recovery, and a 2nd bout of HU at 9 months of age). This thesis focused on the 2HU+Ex data, while utilizing data from other groups for comparisons. The data in this thesis includes ex vivo densitometric and biomechanical properties at the femoral neck (FN), femur midshaft diaphysis (FD), and distal femur metaphysis (DFM). All compartments of BMC increased following exercise recovery above AC at the FN and DFM. Ambulatory recovery values revealed incomplete recovery in total and cortical BMC at the DFM and full recovery in other parameters. DFM and FD vBMD data indicated there were further benefits of exercise during recovery. Geometric data revealed periosteal apposition at the DFM and FN following exercise recovery. FD mechanical properties did not produce benefits of exercise. However, FN maximum force increased above all other groups after exercise recovery. Elastic modulus of the DFM showed benefits of exercise recovery in the response to the 2nd HU.
3

MicroRNA expression profiling in endometrial adenocarcinoma

Jurcevic, Sanja January 2015 (has links)
No description available.
4

Alteration of cartilage-surface collagen fibers differs locally after immobilization of knee joints in rats / ラット膝関節不動後の軟骨表面のコラーゲン線維変化は領域により異なる

Nagai, Momoko 25 May 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第19180号 / 人健博第28号 / 新制||人健||3(附属図書館) / 32172 / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 高桑 徹也, 教授 市橋 則明, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM
5

A pivotal role for interleuking-4 in Atorvastatin-associated neuroprotection in rat brain.

Clarke, R.M., Lyons, A., O'Connell, F., Deighan, B.F., Barry, C.E., Anyakoha, Ngozi G., Nicolaou, Anna, Lynch, M.A. January 2008 (has links)
No / Inflammatory changes, characterized by an increase in pro-inflammatory cytokine production and up-regulation of the corresponding signaling pathways, have been described in the brains of aged rats and rats treated with the potent immune modulatory molecule lipopolysaccharide (LPS). These changes have been coupled with a deficit in long-term potentiation (LTP) in hippocampus. The evidence suggests that anti-inflammatory agents, which attenuate the LPS-induced and age-associated increase in hippocampal interleukin-1ß (IL-1ß) concentration, lead to restoration of LTP. Here we report that atorvastatin, a member of the family of agents that act as inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, exerts powerful anti-inflammatory effects in brain and that these effects are mediated by IL-4 and independent of its cholesterol-lowering actions. Treatment of rats with atorvastatin increased IL-4 concentration in hippocampal tissue prepared from LPS-treated and aged rats and abrogated the age-related and LPS-induced increases in pro-inflammatory cytokines, interferon-¿ (IFN¿) and IL-1ß, and the accompanying deficit in LTP. The effect of atorvastatin on the LPS-induced increases in IFN¿ and IL-1ß was absent in tissue prepared from IL-4¿/¿ mice. The increase in IL-1ß in LPS-treated and aged rats is associated with increased microglial activation, assessed by analysis of major histocompatibility complex II expression, and the evidence suggests that IFN¿ may trigger this activation. We propose that the primary effect of atorvastatin is to increase IL-4, which antagonizes the effects of IFN¿, the associated increase in microglial activation, and the subsequent cascade of events.
6

Essai du traitement pré-clinique du carcinome hépatocellulaire sur la cirrhose dans le modèle de rat / Pre-trial of hepatocellular carcinoma on cirrhosis in a rat model

Zeybek, Ayça 22 December 2016 (has links)
Hepatocellular carcinoma (HCC) is the second most common cause of cancerrelated mortality worldwide. AKT pathway has been found activated in 50% of HCC cases, making it promising target. Therefore we assess efficacy of the allosteric AKT inhibitor or the combination of Sorafenib with AKT inhibitor compared to untreated control and to standard treatment, Sorafenib, in vitro and in vivo. AKT inhibitor blocked phosphorylation of AKT in vitro and strongly inhibited cell growth with significantly higher potency than Sorafenib. Similarly, apoptosis and cell migration were strongly reduced by AKT inhibitor in vitro. To mimic human advanced HCC, we used diethylnitrosamine-induced cirrhotic rat model with fully developed HCC. MRI analyses showed that AKT inhibitor significantly reduced overall tumor size. Furthermore, number of tumors was decreased by AKT inhibitor, which was associated with increased apoptosis and decreased proliferation. Tumor contrast enhancement was significantly decreased in the AKT inhibitor group. Moreover, on tumor tissue sections, we observed a vascular normalization and a significant decrease in fibrosis in surrounding liver of animals treated with AKT inhibitor. Finally, pAKT/AKT levels in AKT inhibitor treated tumors were reduced, followed by down regulation of actors of AKT downstream signalling pathway: pmTOR, pPRAS40, pPLCγ1 and pS6K1. In conclusion, we demonstrated that AKT inhibitor blocks AKT phosphorylation in vitro and in vivo. In HCC-rat model, AKT inhibitor was well tolerated, showed anti-fibrotic effect and had stronger antitumor effect than Sorafenib. Our results confirm the importance of targeting AKT in HCC. / Hepatocellular carcinoma (HCC) is the second most common cause of cancerrelated mortality worldwide. AKT pathway has been found activated in 50% of HCC cases, making it promising target. Therefore we assess efficacy of the allosteric AKT inhibitor or the combination of Sorafenib with AKT inhibitor compared to untreated control and to standard treatment, Sorafenib, in vitro and in vivo. AKT inhibitor blocked phosphorylation of AKT in vitro and strongly inhibited cell growth with significantly higher potency than Sorafenib. Similarly, apoptosis and cell migration were strongly reduced by AKT inhibitor in vitro. To mimic human advanced HCC, we used diethylnitrosamine-induced cirrhotic rat model with fully developed HCC. MRI analyses showed that AKT inhibitor significantly reduced overall tumor size. Furthermore, number of tumors was decreased by AKT inhibitor, which was associated with increased apoptosis and decreased proliferation. Tumor contrast enhancement was significantly decreased in the AKT inhibitor group. Moreover, on tumor tissue sections, we observed a vascular normalization and a significant decrease in fibrosis in surrounding liver of animals treated with AKT inhibitor. Finally, pAKT/AKT levels in AKT inhibitor treated tumors were reduced, followed by down regulation of actors of AKT downstream signalling pathway: pmTOR, pPRAS40, pPLCγ1 and pS6K1. In conclusion, we demonstrated that AKT inhibitor blocks AKT phosphorylation in vitro and in vivo. In HCC-rat model, AKT inhibitor was well tolerated, showed anti-fibrotic effect and had stronger antitumor effect than Sorafenib. Our results confirm the importance of targeting AKT in HCC.
7

Análise comparativa in vitro do efeito da osteoporose no comportamento de células osteoblásticas da medula óssea e da calvária de ratas ovariectomizadas / Comparative analysis of the effect of osteoporosis on the in vitro behavior of bone marrow and calvaria osteoblastic cells from female ovariectomized rats

Azevedo, Fernanda Grilo de 29 August 2014 (has links)
A osteoporose, uma doença óssea progressiva, é considerada um grave problema de saúde pública, sendo uma das condições mais importantes associadas ao envelhecimento e que afeta milhões de pessoas no mundo. Esta doença multifatorial é caracterizada pela densidade óssea reduzida e deterioração da microarquitetura óssea. O objetivo deste trabalho foi investigar as mudanças comportamentais em células mesenquimais da medula óssea e células osteoblásticas da calvária de ratas induzidas à osteoporose. Após aprovação da Comissão de Ética no Uso de Animais, 18 ratas Wistar foram utilizadas e divididas em grupos controle e ovariectomizadas. Após 150 dias, as ratas de ambos os grupos foram sacrificadas para coleta dos fêmures e fragmentos da calvária. As células recolhidas a partir da medula óssea e calvária foram cultivadas em placas de 24 poços (n = 5) para avaliação da proliferação e viabilidade celular, atividade de fosfatase alcalina (ALP), detecção e quantificação de nódulos mineralizados e análise da expressão gênica por meio de PCR em tempo real. Os dados foram submetidos ao testes de Kruskal-Wallis e Mann-Whitney, com nível de significância de 5%. As células da medula óssea do grupo controle (MC) mostraram uma diminuição significativa na proliferação quando comparado com as células do grupo controle da calvária (CC) em todos os períodos (p < 0,05). Por outro lado, as células da medula óssea de ratas com osteoporose (MO) revelaram um aumento significativo na taxa de proliferação após 7 e 10 dias (p < 0,01) em comparação às células da calvária de ratas ovariectomizadas (CO). A viabilidade celular foi maior em todos os períodos estudados dos grupos CC e CO em relação aos grupos MC e MO (p < 0,05). A atividade de fosfatase alcalina não foi significativamente diferente após 7 dias de cultura entre os grupos estudados; por outro lado, após 10 e 14 dias, observou-se uma diminuição da sua atividade no grupo MC quando comparado ao grupo CC (p < 0,01). Nas ratas com osteoporose, as células da medula óssea mostraram um aumento desta atividade quando comparada às células de calvária (p < 0,01). A análise dos nódulos mineralizados após 14 e 21 dias revelou que os grupos controle CC e MC não apresentaram diferenças significativas, ao passo que no grupo MO observou-se um aumento da mineralização quando comparado ao grupo CO nos mesmos períodos experimentais. Os resultados obtidos na análise de expressão gênica mostraram que para os genes Runx2, Oc, Alpl, Rank-l e Er&alpha; a expressão no grupo MO foi maior que no grupo MC (p < 0,05), enquanto que para as células da calvária, CC teve maior expressão gênica que CO (p < 0,05). Os genes Opg e Er&beta; apresentaram variações de acordo com o grupo avaliado. Frente aos resultados obtidos, sugere-se que existam alterações no metabolismo das células progenitoras e células diferenciadas após a indução da osteoporose e que as células da medula óssea apresentam um aumento da sua função como uma resposta compensatória neste modelo animal ovariectomizado. / Osteoporosis, a progressive bone disease, is considered a serious public health problem, being one of the most important conditions associated with aging, affecting millions of people worldwide. This multifactorial disease is characterized by reduced bone density and deterioration of bone microarchitecture. The objective of this work was to investigate the behavioral changes in mesenchymal cells from bone marrow and osteoblastic cells from calvaria bone of female rats induced to osteoporosis. After institutional review board approval, 18 Wistar female rats were used and divided into control and ovariectomized groups. After 150 days, the rats of both groups were sacrificed for collection of femurs and calvariae fragments. The cells collected from bone marrow and calvaria were cultured in 24-well plates (n=5) for the assessment of cell proliferation and viability, alkaline phosphatase (ALP) activity and detection and quantification of mineralized nodules. The data were submitted to Kruskal-Wallis and Mann-Whitney tests, with significance level set at 5%. The cells from bone marrow control group (MC) showed a significantly decrease in proliferation when compared to the cells from calvaria bone control group (CC) in all periods evaluated (p < 0,05). On the other hand, bone marrow cells from osteoporotic rats (MO) revealed a significant increase in their proliferation rate after 7 and 10 days (p < 0,01) compared to calvaria cells from ovariectomized rats (CO). Cell viability was higher in all investigated periods of CC and CO groups compared to MC and MO groups (p < 0,05). Alkaline phosphatase activity was not significantly different after 7 days of culture among the studied groups; in spite of that, after 10 and 14 days, there was a decrease in its activity in MC group when compared to CC (p < 0,01). In the osteoporotic rats, bone marrow cells showed an increase in this activity when compared to calvaria cells (p < 0,01). The analysis of mineralized nodules after 14 and 21 days revealed that control groups (CC and MC) did not have significant differences, whereas it was observed in MO group an increase in the mineralization when compared to CO in the same experimental periods. The data obtained in the analysis of gene expression showed that for Runx2, Oc, Alpl, Rank-l and Er&alpha; genes, the expression in MO group was higher than in MC (p < 0,05), whereas for the calvaria cells, CC group had higher gene expression than CO group (p < 0,05). The Opg and Er&beta; genes showed variations according to the evaluated group. Thus, it is suggested that there are changes in the metabolism of progenitor and differentiated cells after osteoporosis induction and that bone marrow cells present an enhancement of their function as a compensatory response in this ovariectomized rat model.
8

Influence of early life and positive affect on feeding behaviour and food choice in the rat

Warnock, Amy Louise January 2018 (has links)
In recent years, worldwide obesity rates have risen dramatically, putting major strain on public health systems and the economy. Obesity is a multifaceted disease and its development can be influenced by a variety of factors including genetic, psychological and environmental influences. One area of current focus in obesity research is that of early life programming. It has been well-established that certain early life factors can impact the physiology and behaviour of the offspring. Because of this, early life programming has become increasingly well studied in order to develop a deeper understanding of how early life can influence obesity development. Another area of interest lies in positive mood. While there has been much research into the effects of negative states such as stress and anxiety on feeding behaviour, there is still very little known about how positive states can influence food choice. Using rat models of prenatal stress, neonatal overnutrition and positive affect, this thesis aimed to investigate the effects of early life and mood factors on feeding behaviour and food choice. Prenatal stress has been extensively studied and is characterised by an enhanced stress response in the offspring. Using two rat models of prenatal stress- social and restraint stress, the effects of prenatal stress on feeding behaviour and food choice in the offspring were examined. In both models, no effects of prenatal stress on either food intake or food choice were observed. However, in both cases the expected alterations to the offspring's stress responses when exposed to an acute stressor were not replicated. This may suggest that models of prenatal stress are not as robust as often cited in the literature. As well as the prenatal environment, the early postnatal environment is also able to influence physiology and behaviour. In terms of obesity, a well-studied model is that of small litter size. Rats from small litters are over-nourished as neonates and because of this illustrate an increased body weight that persists throughout life. While this increase in weight gain has been well-established, there is no evidence examining the impact of neonatal overnutrition on long-term food choice. Therefore, food intake and food choice were measured in small and control litter rats over a 10-week period. When placed on an ad lib diet of bland chow, sucrose and lard, small litter rats consumed significantly more chow than control litter rats, whilst maintaining similar consumption of lard and sucrose. However, when offered a high-fat high-sugar (HFHS) pellet for two hours a day alongside ad lib chow, small litter rats illustrated increased consumption of the HFHS pellet compared to controls. This suggests that small litter rats may be programmed to adjust their food choices to enable them to maintain their increased body weight in comparison to controls. To examine the effects of positive affect on feeding behaviour, ultrasonic vocalisations (USVs, specifically those at 50 kHz) were used as a measure of positive affect in rats. In order to examine whether access to a food reward could induce a positive affect (as measured by an increase in 50 kHz USVs), rats were schedule-fed sweetened condensed milk and USVs measured before, during and after consumption. No differences in 50 kHz USVs were observed suggesting that a palatable food, whilst rewarding, does not alter affective state in the rat. Using heterospecific social contact (a tickling interaction simulating rough and tumble play) to induce positive affect, rats were presented with an hour-long sucrose preference test following social contact in order to examine the impact of positive affect on food choice. While no differences in sucrose consumption were found, a reduced sucrose preference was observed in rats receiving social contact compared to controls, suggesting that positive affect may play a role in mediating food choice. Finally, the effects of fasting (a negative stimulus thought to reduce 50 kHz USVs) and a food reward on motivation for social contact were examined. Both fasting and access to a food reward resulted in no differences in conditioned place preference to receive social interaction. Overall, the results obtained in this thesis implicate both neonatal overnutrition and, for the first time, positive affect as possible mediators of food choice, although further studies are required to fully establish these effects. Importantly, these results also raise questions regarding the reproducibility of some early life models, such as prenatal stress, and highlights the importance of sharing precise experimental protocols across laboratories. Through further investigation of the effects of early life and affective states on food consumption and choice, and the mechanisms behind these, this may enable the development of therapeutic interventions and preventative measures that can help slow, or even reverse, the global obesity epidemic.
9

Noninvasive monitoringn of CCl4 induced acute and chronic liver damage in rat by single quantum and triple quantum filtered 23Na magnetic resonance imaging

Gao, Yong. January 2008 (has links)
Thesis (M.S.)--Indiana University, 2008. / Title from screen (viewed on January 26, 2010). Department of Cellular & Integrative Physiology, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Navin Bansal, Andriy M. Babsky, Stephen A. Kempson, David P. Basile. Includes vitae. Includes bibliographical references (leaves 33-36).
10

THE TRANSPORT AND MODULATION OF HIV PROTEASE INHIBITORS INTO THE RAT CENTRAL NERVOUS SYSTEM AND MILK

Edwards, Jeffrey Earl 01 January 2004 (has links)
The objective of this dissertation is to study the mechanism by which HIV protease inhibitors enter into the central nervous system (CNS) and breast milk of rats, and what effects MDR modulators have on the distribution and metabolism of HIV protease inhibitors. The transporter P-glycoprotein (P-gp) has been shown to limit the distribution of HIV protease inhibitors into the CNS of rodents. This thesis examined the effects of GF120918, an MDR modulator, on the CNS distribution of amprenavir, an HIV protease inhibitor, in rats. GF120918 significantly increased the unbound CNS concentrations of amprenavir without altering the unbound blood concentrations of amprenavir. The results of these studies show that GF120918 can inhibit P-gp at the blood brain barrier (BBB) to increase the unbound CNS concentration of amprenavir and potentially other HIV protease inhibitors. Many first generation MDR modulators inhibited both P-gp transport and CYP3A metabolism. Therefore, a principal goal of this thesis was to determine if GF120918 could selectively inhibit P-gp transport without inhibiting CYP3A metabolism. Using in vitro (human) and in vivo (rat) studies, GF120918 selectively inhibited P-gp at the BBB without inhibiting CYP3A metabolism. The transporter MRP1 has been shown to both transport HIV protease inhibitors and expressed in the CNS. Studies contained in the thesis have shown that mrp1 is not localized to the BBB of rats, therefore, mrp1 is unlikely to play a significant role in the distribution of HIV protease inhibitors into the CNS of rats. The distribution of nelfinavir, an HIV protease inhibitor, into rat breast milk was studied in the thesis as a first approach in understanding the extent to which HIV protease inhibitors can accumulate into milk. The concentration of nelfinavir in rat milk was approximately half that of plasma. P-gp protein expression was detected in lactating rat mammary tissue. However, GF120918 showed no effect on the distribution of nelfinavir into rat milk suggesting that P-gp does not play a significant role in the distribution of HIV protease inhibitors into milk.

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