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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.
111

Efeito da hipoxia intermitente em marcadores de progressão de melanoma em um modelo de apneia do sono em camundongos

Perini, Silvana January 2013 (has links)
Objetivos do Estudo: O aumento do crescimento de melanoma foi avaliado em camundongos expostos a hipóxia intermitente. As proteínas que caracterizam a agressividade do tumor ainda não foram investigadas. O estudo teve como objetivo verificar se a hipóxia intermitente simulada pela apneia do sono afeta marcadores de melanoma na progressão tumoral. Desenho: Estudo prospectivo controlado em animais. Senário: Hospital Universitário. Participantes: Doze camundongos C57BL/6. Intervenções: Camundongos foram expostos a hipóxia intermitente ou simulada. Durante 8 horas por dia, o grupo hipóxia foi submetido a um total de 480 ciclos de 30 segundos de hipóxia progressiva SpO2 nadir de 8 ± 1%, seguidos por 30 segundos de normóxia. Um milhão de células de melanoma B16F10 foi injetado por via subcutânea. No dia 14, após a eutanásia, os tumores foram removidos, fixados e corados. Médias e resultados: coloração imunohistoquímica de Ki-67, PCNA, S100-B, HMB-45, Melan-A, TGF, Caspase-1 e HIF-1α foi quantificada por dois observadores que utilizaram captura digital e processamento em três lâminas de cada animal para cada marcador. O tamanho e o peso dos tumores foram semelhantes nas experiências de hipóxia e simulada. A percentagem da mediana [25-75 quartis] de área positiva corada para Ki-67 foi de 23% [15-28] no grupo hipóxia e 0,3% [0,2-1,1] no grupo controle (P = 0,02); para PCNA, as percentagens foram 31% [25-38] e 7% [5-18], respectivamente (P = 0,009). As diferenças entre os grupos para os marcadores restantes não foram significativas. Conclusões: Os marcadores da transcrição do RNA ribossomal e da síntese de DNA são mais expressos em tumores de camundongos expostos a hipóxia intermitente do que em controles, indicando que a apneia do sono pode levar a uma maior agressividade do tumor. / Study Objectives: Increased melanoma growth has been reported in mice exposed to intermittent hypoxia. Proteins that characterize tumor aggressiveness have not been investigated. The study aims to verify whether intermittent hypoxia mimicking sleep apnea affects markers of melanoma tumor progression. Design: Prospective controlled animal study. Settings: University hospital. Participants: Twelve C57bl/6 mice. Interventions: Mice were exposed to intermittent or sham hypoxia. During 8 hours per day, the hypoxia group was submitted to a total of 480 cycles of 30 seconds of progressive hypoxia to a nadir FIO2 of 8±1%, followed by 30 seconds of normoxia. One million B16F10 melanoma cells were injected subcutaneously. On the 14th day, after euthanasia, tumors were removed, fixed and stained. Measurements and Results: Immunohistochemistry staining for Ki-67, PCNA, S100-B, HMB-45, Melan-A, TGFβ, Caspase-1 and HIF-1α was quantified by two observers using digital capture and processing in three slides from each animal for each marker. The size and weight of the tumors were similar in hypoxia and simulated experiments. Median [25-75 quartiles] percentage of positive area stained for Ki-67 was 23% [15-28] in the hypoxia group and 0.3% [0.2-1.1] the control group (P=0.02); for PCNA, the percentages were 31% [25-38] e 7% [5-18], respectively (P=0.009). The differences between the groups for the remaining markers were not significant. Conclusions: Markers of ribosomal RNA transcription and of DNA synthesis are more expressed in tumors of mice exposed to intermittent hypoxia than of controls, indicating that sleep apnea can lead to greater tumor aggressiveness.
112

The Relationship Between Adult Hippocampal Neurogenesis and Spatial Learning and Memory in Natural Populations of Food-storing Red Squirrels (Tamiasciurus hudsonicus).

Johnson, Kristin Margaret 24 February 2009 (has links)
Previous research on the relationship between spatial memory and adult hippocampal neurogenesis has been controversial. In the present study, neurogenesis was compared between two natural populations of the same species that differ in their reliance on spatial memory to cache and retrieve stored food. Western red squirrels store food in a single site whereas eastern red squirrels store food in multiple sites. Neurogenesis was assessed using endogenous markers of the number of proliferating cells (Ki-67) and the number of immature neurons (DCX), and neuronal recruitment was determined by measuring the area of the dentate gyrus of the hippocampus. The number of proliferating cells, immature neurons and neuronal recruitment were enhanced in the eastern compared to the western red squirrels, reflecting the food storing strategies used by the squirrels. This suggests that there is a positive correlation between adult hippocampal neurogenesis and spatial learning and memory.
113

The Relationship Between Adult Hippocampal Neurogenesis and Spatial Learning and Memory in Natural Populations of Food-storing Red Squirrels (Tamiasciurus hudsonicus).

Johnson, Kristin Margaret 24 February 2009 (has links)
Previous research on the relationship between spatial memory and adult hippocampal neurogenesis has been controversial. In the present study, neurogenesis was compared between two natural populations of the same species that differ in their reliance on spatial memory to cache and retrieve stored food. Western red squirrels store food in a single site whereas eastern red squirrels store food in multiple sites. Neurogenesis was assessed using endogenous markers of the number of proliferating cells (Ki-67) and the number of immature neurons (DCX), and neuronal recruitment was determined by measuring the area of the dentate gyrus of the hippocampus. The number of proliferating cells, immature neurons and neuronal recruitment were enhanced in the eastern compared to the western red squirrels, reflecting the food storing strategies used by the squirrels. This suggests that there is a positive correlation between adult hippocampal neurogenesis and spatial learning and memory.
114

Chronic Deep Brain Stimulation and Pharmacotherapy for the Treatment of Depression: Effects on Neuroplasticity in Rats

Isabella, Silvia 30 May 2011 (has links)
Deep brain stimulation (DBS) is currently being investigated as a therapy for treatment-resistant depression, with promising results. However, it is not clear whether or not DBS works via the same mechanisms as those induced by antidepressant medications. Processes currently implicated in antidepressant effects include neuroplastic changes and promotion of neurogenesis. We investigated the effects of chronic treatment with three different classes of antidepressants and DBS on markers of neuroplasticity (brain-derived neurotrophic factor, (BDNF), and phosphorylated cyclic-AMP regulatory element binding protein, (pCREB)) and neurogenesis (Ki-67, bromodeoxyuridine (BrdU) and doublecortin) in the rat hippocampus. No clear treatment effects were seen on BDNF, pCREB and Ki-67 levels. However all treatments caused increased levels of BrdU (range: 46%-96%) and doublecortin (8%-61%), although these effects were statistically significant only for DBS and amitriptyline, respectively. This overall pattern of results may suggest that diverse antidepressant treatments could possibly share common mechanisms involving cell survival and neuronal differentiation. Potentiated effects of DBS on cell survival may underlie its efficacy in treatment-resistant depression.
115

Chronic Deep Brain Stimulation and Pharmacotherapy for the Treatment of Depression: Effects on Neuroplasticity in Rats

Isabella, Silvia 30 May 2011 (has links)
Deep brain stimulation (DBS) is currently being investigated as a therapy for treatment-resistant depression, with promising results. However, it is not clear whether or not DBS works via the same mechanisms as those induced by antidepressant medications. Processes currently implicated in antidepressant effects include neuroplastic changes and promotion of neurogenesis. We investigated the effects of chronic treatment with three different classes of antidepressants and DBS on markers of neuroplasticity (brain-derived neurotrophic factor, (BDNF), and phosphorylated cyclic-AMP regulatory element binding protein, (pCREB)) and neurogenesis (Ki-67, bromodeoxyuridine (BrdU) and doublecortin) in the rat hippocampus. No clear treatment effects were seen on BDNF, pCREB and Ki-67 levels. However all treatments caused increased levels of BrdU (range: 46%-96%) and doublecortin (8%-61%), although these effects were statistically significant only for DBS and amitriptyline, respectively. This overall pattern of results may suggest that diverse antidepressant treatments could possibly share common mechanisms involving cell survival and neuronal differentiation. Potentiated effects of DBS on cell survival may underlie its efficacy in treatment-resistant depression.
116

Efeito da hipoxia intermitente em marcadores de progressão de melanoma em um modelo de apneia do sono em camundongos

Perini, Silvana January 2013 (has links)
Objetivos do Estudo: O aumento do crescimento de melanoma foi avaliado em camundongos expostos a hipóxia intermitente. As proteínas que caracterizam a agressividade do tumor ainda não foram investigadas. O estudo teve como objetivo verificar se a hipóxia intermitente simulada pela apneia do sono afeta marcadores de melanoma na progressão tumoral. Desenho: Estudo prospectivo controlado em animais. Senário: Hospital Universitário. Participantes: Doze camundongos C57BL/6. Intervenções: Camundongos foram expostos a hipóxia intermitente ou simulada. Durante 8 horas por dia, o grupo hipóxia foi submetido a um total de 480 ciclos de 30 segundos de hipóxia progressiva SpO2 nadir de 8 ± 1%, seguidos por 30 segundos de normóxia. Um milhão de células de melanoma B16F10 foi injetado por via subcutânea. No dia 14, após a eutanásia, os tumores foram removidos, fixados e corados. Médias e resultados: coloração imunohistoquímica de Ki-67, PCNA, S100-B, HMB-45, Melan-A, TGF, Caspase-1 e HIF-1α foi quantificada por dois observadores que utilizaram captura digital e processamento em três lâminas de cada animal para cada marcador. O tamanho e o peso dos tumores foram semelhantes nas experiências de hipóxia e simulada. A percentagem da mediana [25-75 quartis] de área positiva corada para Ki-67 foi de 23% [15-28] no grupo hipóxia e 0,3% [0,2-1,1] no grupo controle (P = 0,02); para PCNA, as percentagens foram 31% [25-38] e 7% [5-18], respectivamente (P = 0,009). As diferenças entre os grupos para os marcadores restantes não foram significativas. Conclusões: Os marcadores da transcrição do RNA ribossomal e da síntese de DNA são mais expressos em tumores de camundongos expostos a hipóxia intermitente do que em controles, indicando que a apneia do sono pode levar a uma maior agressividade do tumor. / Study Objectives: Increased melanoma growth has been reported in mice exposed to intermittent hypoxia. Proteins that characterize tumor aggressiveness have not been investigated. The study aims to verify whether intermittent hypoxia mimicking sleep apnea affects markers of melanoma tumor progression. Design: Prospective controlled animal study. Settings: University hospital. Participants: Twelve C57bl/6 mice. Interventions: Mice were exposed to intermittent or sham hypoxia. During 8 hours per day, the hypoxia group was submitted to a total of 480 cycles of 30 seconds of progressive hypoxia to a nadir FIO2 of 8±1%, followed by 30 seconds of normoxia. One million B16F10 melanoma cells were injected subcutaneously. On the 14th day, after euthanasia, tumors were removed, fixed and stained. Measurements and Results: Immunohistochemistry staining for Ki-67, PCNA, S100-B, HMB-45, Melan-A, TGFβ, Caspase-1 and HIF-1α was quantified by two observers using digital capture and processing in three slides from each animal for each marker. The size and weight of the tumors were similar in hypoxia and simulated experiments. Median [25-75 quartiles] percentage of positive area stained for Ki-67 was 23% [15-28] in the hypoxia group and 0.3% [0.2-1.1] the control group (P=0.02); for PCNA, the percentages were 31% [25-38] e 7% [5-18], respectively (P=0.009). The differences between the groups for the remaining markers were not significant. Conclusions: Markers of ribosomal RNA transcription and of DNA synthesis are more expressed in tumors of mice exposed to intermittent hypoxia than of controls, indicating that sleep apnea can lead to greater tumor aggressiveness.
117

Efeito da hipoxia intermitente em marcadores de progressão de melanoma em um modelo de apneia do sono em camundongos

Perini, Silvana January 2013 (has links)
Objetivos do Estudo: O aumento do crescimento de melanoma foi avaliado em camundongos expostos a hipóxia intermitente. As proteínas que caracterizam a agressividade do tumor ainda não foram investigadas. O estudo teve como objetivo verificar se a hipóxia intermitente simulada pela apneia do sono afeta marcadores de melanoma na progressão tumoral. Desenho: Estudo prospectivo controlado em animais. Senário: Hospital Universitário. Participantes: Doze camundongos C57BL/6. Intervenções: Camundongos foram expostos a hipóxia intermitente ou simulada. Durante 8 horas por dia, o grupo hipóxia foi submetido a um total de 480 ciclos de 30 segundos de hipóxia progressiva SpO2 nadir de 8 ± 1%, seguidos por 30 segundos de normóxia. Um milhão de células de melanoma B16F10 foi injetado por via subcutânea. No dia 14, após a eutanásia, os tumores foram removidos, fixados e corados. Médias e resultados: coloração imunohistoquímica de Ki-67, PCNA, S100-B, HMB-45, Melan-A, TGF, Caspase-1 e HIF-1α foi quantificada por dois observadores que utilizaram captura digital e processamento em três lâminas de cada animal para cada marcador. O tamanho e o peso dos tumores foram semelhantes nas experiências de hipóxia e simulada. A percentagem da mediana [25-75 quartis] de área positiva corada para Ki-67 foi de 23% [15-28] no grupo hipóxia e 0,3% [0,2-1,1] no grupo controle (P = 0,02); para PCNA, as percentagens foram 31% [25-38] e 7% [5-18], respectivamente (P = 0,009). As diferenças entre os grupos para os marcadores restantes não foram significativas. Conclusões: Os marcadores da transcrição do RNA ribossomal e da síntese de DNA são mais expressos em tumores de camundongos expostos a hipóxia intermitente do que em controles, indicando que a apneia do sono pode levar a uma maior agressividade do tumor. / Study Objectives: Increased melanoma growth has been reported in mice exposed to intermittent hypoxia. Proteins that characterize tumor aggressiveness have not been investigated. The study aims to verify whether intermittent hypoxia mimicking sleep apnea affects markers of melanoma tumor progression. Design: Prospective controlled animal study. Settings: University hospital. Participants: Twelve C57bl/6 mice. Interventions: Mice were exposed to intermittent or sham hypoxia. During 8 hours per day, the hypoxia group was submitted to a total of 480 cycles of 30 seconds of progressive hypoxia to a nadir FIO2 of 8±1%, followed by 30 seconds of normoxia. One million B16F10 melanoma cells were injected subcutaneously. On the 14th day, after euthanasia, tumors were removed, fixed and stained. Measurements and Results: Immunohistochemistry staining for Ki-67, PCNA, S100-B, HMB-45, Melan-A, TGFβ, Caspase-1 and HIF-1α was quantified by two observers using digital capture and processing in three slides from each animal for each marker. The size and weight of the tumors were similar in hypoxia and simulated experiments. Median [25-75 quartiles] percentage of positive area stained for Ki-67 was 23% [15-28] in the hypoxia group and 0.3% [0.2-1.1] the control group (P=0.02); for PCNA, the percentages were 31% [25-38] e 7% [5-18], respectively (P=0.009). The differences between the groups for the remaining markers were not significant. Conclusions: Markers of ribosomal RNA transcription and of DNA synthesis are more expressed in tumors of mice exposed to intermittent hypoxia than of controls, indicating that sleep apnea can lead to greater tumor aggressiveness.
118

Associação da expressão do Ki67 e linfonodos axilares metastáticos com a sobrevida livre de doença no câncer de mama invasivo

PAIVA, Carina Batista 23 February 2016 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-08-09T14:09:09Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertaçao_Carina_Paiva_PPG_MESTRADO_PATOLOGIA_TURMA2014-2016.pdf: 7682349 bytes, checksum: 18a47d04a840b2356f9461b6b6d72f96 (MD5) / Made available in DSpace on 2017-08-09T14:09:09Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertaçao_Carina_Paiva_PPG_MESTRADO_PATOLOGIA_TURMA2014-2016.pdf: 7682349 bytes, checksum: 18a47d04a840b2356f9461b6b6d72f96 (MD5) Previous issue date: 2016-02-23 / Marcadores biológicos são requeridos para estimar o risco de recorrência da doença em mulheres com câncer de mama. O Ki67 é um marcador de proliferação celular e seu valor preditivo e prognóstico tem sido estudado como um importante biomarcador de rotina na prática clínica. Nosso estudo teve como objetivo avaliar a relação entre a intensidade da expressão do Ki-67 e o envolvimento de linfonodos axilares com metástases com a sobrevida livre de doença em mulheres com câncer de mama. Esse estudo foi retrospectivo e 134 pacientes foram elegíveis para o estudo. A associação entre os escores do Ki67 e outros fatores prognósticos, tais como tamanho do tumor, grau, status dos linfonodos axilares, invasão perineural e linfovascular, biomarcadores RE, RPg e HER-2 foram avaliados, além da análise de sobrevivência. Dos 134 pacientes, 53 tiveram recorrência da doença. O valor da mediana dos escores do Ki67 foi de 30% de todos os pacientes. Um total de 78 (58,25) dos pacientes tiverm escores alto do Ki67. A associação estatisticamente significante foi entre os escores altos do Ki67 com o grau histológico (p<0.001), subtipos moleculares (p<0.001), receptores de estrógeno (p=0.023) e receptores de progesterona (p=0.001). A sobrevida livre de doença em indivíduos com Ki67 alto e axila clinicamente negativa apresentou um menor tempo em meses em comparação com os indivíduos com escores do Ki67 baixo (p=0.049). / Biological markers are required to estimate the risk of disease recurrence in women with breast cancer. The Ki 67 is a cell proliferation marker and its predictive and prognostic value has been studied as an important marker in routine clinical practice. Our study aimed to evaluate the relationship between the intensity of Ki67 expression and involvement of axillary lymph nodes with metastases to the disease-free survival in women with breast cancer. This was a retrospective study and 134 patients were eligible for the study. The association between the scores of Ki67 and other prognostic factors such as tumor size, grade, status of axillary lymph nodes, perineural invasion and lymphovascular, in addition to biomarkers ER, PgR, and HER2 were evaluated, as well as survival analysis. Of the 134 patients, 53 have had recurrence of disease. The median value of Ki scores 67 was 30% of all patients. A total of 78 (58.25) of the patients had high scores Ki 67. A statistically significant association was between high scores of Ki67 with the histological grade, molecular subtypes of progesterone receptors estrogen receptors. A statistically significant association was between high scores of Ki67 with the histological grade (p <0.001), molecular subtypes (p <0.001), estrogen receptor (p = 0.023) and progesterone receptors (p = 0.001). The disease-free survival in patients with high Ki67 and clinically negative axilla had a shorter time in months compared to individuals with low Ki67 scores (p = 0.049).
119

The Keyboard Percussion Trios of Toru Takemitsu and Toshi Ichiyanagi, a Lecture Recital, together with Three Recitals of Selected Works of Cahn, Maslanka, Miki, Miyoshi, Ptaszynska, Schultz, Wesley-Smith, and Others

Finnie, Jimmy W. (Jimmy Wayne) 08 1900 (has links)
The purpose of this study is to examine the various signatures of compositional style as manifested in the keyboard percussion trios Rain Tree by Toru Takemitsu and Wind Trace by Toshi Ichiyanagi. Significant personal interaction between the aforementioned Japanese composers and American composer John Cage justifies an investigation of his influence on their compositional styles. Toru Takemitsu is currently one of the most prolific Japanese composers. In 1981, Takemitsu composed the percussion trio Rain Tree. Three years later (1984) the Japanese concert pianist Toshi Ichiyanagi composed Wind Trace using Rain Tree's identical instrumentation of marimba, vibraphone, and crotales. Rain Tree and Wind Trace are very similar in compositional style. Formally, both works are single-movement compositions employing rhythmic tension, harmonic dissonance, and visual imagery created by the use of polyrhythms, aleatory, nonfunctional harmony, and extra-musical references. This study investigates the Japanese philosophy of ma and its influence in Rain Tree and Wind Trace. Ma is the natural pause or interval between two or more phenomena occurring continuously. According to Takemitsu, ma is living space, more than actual space. Both compositions utilize space as an essential compositional technique to either connect compartmentalized activity or to complement melodic material. With the utmost respect for nature, Toru Takemitsu and Toshi Ichiyanagi have synthesized elements of Oriental and Occidental music into compositional styles that are unique yet universal. Functioning within both composer's strong personal aesthetics, the affective use of aleatoric and polyrhythmic structures reflect John Cage's influence. Takemitsu's decision to reevaluate the qualities of Japanese traditional music, and to consciously attempt to express the qualities of nature within his music, are attributable to his associations with John Cage. Rain Tree and Wind Trace are virtuosic vehicles of musical expression for which an understanding of the subtle elements within the Eastern and Western art forms is essential.
120

Ki-67 Regulates Cell Cycle Progression and Heterochromatin Organization

Sun, Xiaoming 15 September 2017 (has links)
A subset of eukaryotic heterochromatin is located around the nucleoli, and this localization is correlated with gene silencing. Although there is some evidence for trans-acting factors organizing genomic loci around the nucleolus, the characterization of proteins and /or RNAs involved in perinculeolar heterochromatin localization and maintenance is incomplete. Notably, the mammalian female inactive X chromosome, a well-studied model of facultative heterochromatin, frequently resides in the perinucleolar regions during mid to late S phase. The disruption of the Xi–nucleolus association results in the erosion of heterochromatin compartment and silencing, which renders it a good model to investigate the mechanism and biological relevance of heterochromatin organization around the nucleolus. This dissertation will present evidence showing that Ki-67 regulates inactive X (Xi) chromosome association with nucleoli, maintains Xi heterochromatic structures, and regulates cell cycle progression, in cell-type-specific manner dependent on checkpoint proficiency. Ki-67 protein plays roles in heterochromatin organization during interphase. Upon Ki-67 depletion, a subset of Xi in human female hTERT-RPE1 moved away from nucleolus and displayed several features of compromised heterochromatin maintenance. These chromatin alterations were limited to Xi chromosomes localized away from the nuclear lamina and were not observed in virally transformed 293T cells upon Ki-67 depletion. Furthermore, I demonstrated that the different Xi heterochromatin alteration responses result from cell-type-specific reduced proportion of cells in S phase upon Ki-67 depletion. In human hTERT-RPE1, WI-38, IMR90, hTERT-BJ cell lines, depletion of Ki-67 slowed entry into S phase and coordinately downregulated genes related to DNA replication. These cell lines are able to induce p21 expression upon Ki-67 depletion. On the contrary, alteration of transcription and cell cycle progression were not observed in tumor-derived HeLa, U2OS and 293T cell lines. These cell lines do not induce p21 expression either. I additionally examined the Ki-67 function in mouse cell cultures. Depletion of Ki-67 neither redistributes inactive X chromosome nor regulates S phase progression in primary female mouse embryonic cells.

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