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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

Maus-tratos na inf?ncia, estresse e envelhecimento celular

Levandowski, Mateus Luz 12 January 2018 (has links)
Submitted by PPG Psicologia (psicologia-pg@pucrs.br) on 2018-01-29T17:22:04Z No. of bitstreams: 1 MATEUS_LUZ_LEVANDOWSKI_DIS.pdf: 8338894 bytes, checksum: 3552e80d2ab07794efd004f518518133 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2018-02-05T12:59:19Z (GMT) No. of bitstreams: 1 MATEUS_LUZ_LEVANDOWSKI_DIS.pdf: 8338894 bytes, checksum: 3552e80d2ab07794efd004f518518133 (MD5) / Made available in DSpace on 2018-02-05T13:02:25Z (GMT). No. of bitstreams: 1 MATEUS_LUZ_LEVANDOWSKI_DIS.pdf: 8338894 bytes, checksum: 3552e80d2ab07794efd004f518518133 (MD5) Previous issue date: 2018-01-12 / We aimed this thesis to explore biological mechanisms of childhood maltreatment exposure in two articles. The first article is an extensive meta-analysis assessing basal and dynamic levels of cortisol in children and adults who have experienced early life stress. We found that children during early childhood exhibit lower basal cortisol levels and lower activation of the HPA axis during stress exposure. Also, we found a biological ecophenotype within individuals with mental disorder and history of childhood maltreatment. In the second article we evaluated children and adolescents in a longitudinal study to assess the impact of early life stress on biomarkers of cell aging. We found that children exposed to maltreatment presented a greater number of behavioral problems, a higher rate of psychiatric diagnosis and accelerated cellular aging compared to children without traumatic exposure. Accelerated cell aging was identified through Telomere Length, Mitochondrial DNA copy number and ND4, being the first study with children to report these variables in association with traumatic experiences. / Esse trabalho buscou compreender mecanismos biol?gicos da exposi??o aos maus-tratos na inf?ncia em dois artigos. O primeiro artigo ? uma extensa meta-an?lise avaliando n?veis basais e din?micos de cortisol em crian?as e adultos que passaram por estresse precoce. Evidenciou-se que crian?as durante a primeira inf?ncia exibem n?veis basais de cortisol mais baixos e menor ativa??o do eixo HPA durante exposi??o ao estresse. Tamb?m foi verificado que indiv?duos que compartilham o mesmo diagn?stico apresentaram diferentes n?veis de cortisol se tiverem ou n?o sido expostos a maus-tratos durante a inf?ncia, revelando um ecofen?tipo biol?gico nestes indiv?duos. No segundo artigo foram avaliadas crian?as e adolescentes em um estudo longitudinal para avaliar o impacto do estresse precoce em marcadores de envelhecimento celular. Foi encontrado que crian?as expostas a maus-tratos apresentam maior n?mero de problemas comportamentais, maior taxa de diagn?stico psiqui?trico e envelhecimento celular acelerado em compara??o com crian?as sem exposi??o traum?tica. O envelhecimento celular acelerado foi identificado atrav?s de importantes biomarcadores de envelhecimento, tais como comprimento de tel?mero, n?mero de c?pias de DNA mitocondrial e ND4, sendo o primeiro estudo com crian?as a relacionar estas vari?veis com a exposi??o traum?tica.
2

Padr?es temporais e grau de diversifica??o cariot?pica em esp?cies atl?nticas da fam?lia Acanthuridae (Perciformes)

Fernandes, Maria Aparecida 26 March 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-10T22:12:31Z No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-17T23:45:01Z (GMT) No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) / Made available in DSpace on 2016-03-17T23:45:01Z (GMT). No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) Previous issue date: 2015-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / A fam?lia Acanthuridae ? um grupo bastante representativo dentre os peixes marinhos e que desempenha um papel fundamental na din?mica ecol?gica dos recifes de corais. Tr?s esp?cies pertencentes ao g?nero Acanthurus s?o comuns ao longo dos recifes costeiros do Atl?ntico Ocidental: A. coeruleus, A. bahianus e A. chirurgus. No presente estudo, s?o apresentados dados citogen?ticos para estas tr?s esp?cies de Acanthurus com base em m?todos citogen?ticos cl?ssicos e no mapeamento de sequ?ncias ribossomais repetitivas, como DNAr 18S e 5S, al?m de sondas telom?ricas com a finalidade de auxiliar na compreens?o da carioevolu??o deste grupo. O padr?o citogen?tico dessas esp?cies indica que as etapas sequenciais de rearranjos cromoss?micos, que datam 19-5 milh?es de anos atr?s (Ma), s?o respons?veis por suas diferen?as interespec?ficas. Acanthurus coeruleus (2n=48; 2sm + 4st + 42a), A. bahianus (2n=36; 12m + 2sm + 4st + 18a) e A. chirurgus (2n=34; 12m + 2sm + 4st + 16a) compartilham um antigo conjunto de tr?s pares cromoss?micos originados atrav?s de invers?es peric?ntricas. Um conjunto de seis grandes pares metac?ntricos formados por transloca??es Robertsonianas (Rb) encontrado em A. bahianus e A. chirurgus e uma suposta fus?o em tandem presente em A. chirurgus s?o eventos mais recentes. A falta de sequ?ncias telom?ricas intersticiais (ITS), apesar de v?rias fus?es c?ntricas em A. bahianus e A. chirurgus pode estar relacionada com o longo per?odo de tempo ap?s a sua ocorr?ncia (estimado em 5 Ma). Al?m disso, as homeologias entre os pares de cromossomos que carregam os genes ribossomais, al?m de outras caracter?sticas estruturais, destacam grandes regi?es cromoss?micas conservadas nas tr?s esp?cies. Nossos resultados indicam que as mudan?as macroestruturais ocorreram durante a cladog?nese dessas esp?cies n?o foram seguidas por rearranjos microestruturais vis?veis nos cari?tipos. / The Acanthuridae family is a representative group from the marine fish that plays a key role in ecological dynamics of coral reefs. Three species are common along coastal reefs of Western Atlantic: Acanthurus coeruleus, Acanthurus bahianus and Acanthurus chirurgus. In the present study, cytogenetic data are presented for these three species Acanthurus based on classical cytogenetic methods and mapping of repetitive sequences such as ribosomal 18S and 5S rDNA and telomeric repeats to improve their karyotype evolutionary analyses. The cytogenetic pattern of these species indicated sequential steps of chromosomal rearrangements dating back 19 to 5 millions of years ago (M.a.) that accounted for their interspecific differences. A. coeruleus (2n=48; 2sm+4st+42a), A. bahianus (2n=36; 12m+2sm+4st+18a) and A. chirurgus (2n=34; 12m+2sm+4st+16a) share an older set of three chromosomal pairs that were originated through pericentric inversions. A set of six large metacentric pairs formed by Robertsonian (Rb) translocations found in A. bahianus and A. chirurgus and a putative in tandem fusion found in A. chirurgus are more recent events. The lack of interstitial telomeric sequences (ITS) in spite of several centric fusions in A. bahianus and A. chirurgus might be related to the long period of time after their occurrence (estimated in 5 M.a.). Furthermore, the homeologies among the chromosome pairs bearing ribosomal genes, in addition to other structural features, highlight large conserved chromosomal regions in the three species. Our findings indicate that macrostructural changes occurred during the cladogenesis of these species were not followed by conspicuous microstructural rearrangements in the karyotypes.
3

Efeitos da intensidade do treinamento aer??bio sobre o comprimento do tel??mero e suas prote??nas de prote????o durante o envelhecimento

Cunha, Verusca Najara de Carvalho 14 July 2015 (has links)
Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-04-10T13:40:31Z No. of bitstreams: 1 VeruscaNajaradeCarvalhoCunhaTese2015.pdf: 1703847 bytes, checksum: a9661f4b3c0b28fe801235efd03b727c (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-04-10T13:40:39Z (GMT) No. of bitstreams: 1 VeruscaNajaradeCarvalhoCunhaTese2015.pdf: 1703847 bytes, checksum: a9661f4b3c0b28fe801235efd03b727c (MD5) / Made available in DSpace on 2017-04-10T13:40:39Z (GMT). No. of bitstreams: 1 VeruscaNajaradeCarvalhoCunhaTese2015.pdf: 1703847 bytes, checksum: a9661f4b3c0b28fe801235efd03b727c (MD5) Previous issue date: 2015-07-14 / Telomeres are composed of complex deoxyribonucleic acid and proteins located at the ends of chromosomes, formed by a short sequence of nitrogenous bases (5'-TTAGGGn -3 ') repeated several times. Are connected to a multiprotein complex called "shelterin" consists of six proteins (TRF1, TRF2, POT1, TIN2, RAP1 and TPP1) which maintains telomere homeostasis, preventing degradation. Telomeres are affected by the DNA polymerase inability fully replicate the tape 5' end of the chromosome. The results of such failure are successors shortenings with each cell division, which leads to extremely short telomeres at the end of cell division, resulting in cell senescence. Therefore telomeres are considered a potential biomarker of aging at the cellular level. The shortening of telomeres has been associated with an increased risk of developing age-related diseases such as diabetes, cardiovascular disease and obesity. In contrast, it is believed that physical exercise can attenuate the shortening rate of telomeres, even in the elderly. However, it is possible that there is a 'dose' ideal of physical exercise that can enhance this beneficial effect. The objective of this study was to analyze and compare the effects of aerobic training intensity swimming conducted in two intensity domains (high and low) on the expression of genes encoding the protective telomeric proteins (trf1 and trf2), associated proteins cellular senescence (p53 and Chek2), in addition to measuring telomere length in gastrocnemius and myocardium old mice. Sixteen animals were divided into four groups: two groups submitted to twelve weeks of physical training of swimming at low intensity (BI) and high intensity (AI) and two who remained sedentary for the same period, with a group of young animals (CONTj) and elderly animals (CONTi). Training consisted of swimming exercise three times a week, 20 minutes per session for the group AI and 40 minutes for BI with load corresponding to 3% body weight (%PC) (BI) and 6%PC (AI). An incremental test for functional evaluation was performed every four weeks to measure the maximum load (Gm??x). After the training period, animals were sacrificed for removal of tissue samples for analysis of genes expression related to telomeres. The results suggest that high intensity exercise is "teloprotetor" in the gastrocnemius tissue, since telomere length of the elderly animals did not differ from each other, however, the animals in this group (AI) had a lower expression of genes of proteins protective (trf1 and trf2) and cellular senescence (p53). These results suggest that the intensity at which the exercise is performed interfere with telomere length and that this response is tissue dependent, since the same results were not observed in cardiac tissue of animals. / Tel??meros s??o complexos compostos por ??cido desoxirribonucleico e prote??nas, localizados nas extremidades dos cromossomos, formados por uma pequena sequ??ncia de bases nitrogenadas (5???-TTAGGGn -3???) repetida diversas vezes. Encontram-se ligados a um complexo multiprot??ico denominado ???shelterin??? composto por seis prote??nas (TRF1, TRF2, POT1, TIN2, RAP1 e TPP1) que mant??m a homeostase telom??rica, prevenindo sua degrada????o. Os tel??meros s??o afetados pela incapacidade da DNA polimerase replicar completamente o final da fita 5??? do cromossomo. Os resultados de tal falha s??o sucess??veis encurtamentos a cada divis??o celular, o que leva ?? tel??meros extremamente curtos ao t??rmino das divis??es celulares, resultando na senesc??ncia celular. Sendo assim, considerados um potencial biomarcador do envelhecimento a n??vel celular. O encurtamento dos tel??meros tem sido associado a um maior risco de desenvolvimento de doen??as associadas ao envelhecimento, tais como, diabetes mellitus, doen??as cardiovasculares e obesidade. Em contrapartida, acredita-se que o exerc??cio f??sico possa atenuar a taxa de encurtamento dos tel??meros, mesmo em indiv??duos idosos. Contudo, ?? poss??vel que exista uma ???dose??? ideal de exerc??cio f??sico que possa potencializar este efeito ben??fico. Assim, o objetivo do presente estudo foi analisar e comparar os efeitos do treinamento aer??bio de nata????o realizado em dois dom??nios de intensidade (alta e baixa) sobre a express??o dos genes que codificam as prote??nas de prote????o telom??rica (trf1 e trf2), prote??nas associadas ?? senesc??ncia celular (p53 e Chek2), al??m de mensurar o comprimento do tel??mero no gastrocn??mio e no mioc??rdio de camundongos idosos. Dezesseis animais foram divididos em quatro grupos: dois grupos submetidos a doze semanas de treinamento f??sico de nata????o em baixa intensidade (BI) ou alta intensidade (AI) e dois que permaneceram sedent??rios pelo mesmo per??odo, sendo um grupo de animais jovens (CONTj) e um de animais idosos (CONTi). O treinamento consistiu do exerc??cio de nata????o, tr??s vezes por semana, 20 minutos por sess??o para o grupo AI e 40 minutos para o BI, com carga correspondente a 3% do peso corporal (%PC) (BI) e 6%PC (AI). Um teste incremental para avalia????o funcional fora realizado a cada quatro semanas para mensura????o da carga m??xima (Gm??x). Ap??s o t??rmino do per??odo de treinamento, os animais foram sacrificados para retirada de amostras de tecido para an??lise da express??o dos genes relacionados aos tel??meros. Os resultados obtidos sugerem que o exerc??cio de alta intensidade seja ???teloprotetor??? no tecido gastrocn??mio, uma vez que o comprimento do tel??mero dos animais idosos n??o diferiu entre si, embora, os animais desse grupo (AI) apresentaram uma menor express??o dos genes das prote??nas protetoras (trf1 e trf2) e da senesc??ncia celular (p53). Esses resultados sugerem que a intensidade na qual o exerc??cio ?? realizado interfere no comprimento dos tel??meros e que tal resposta ?? tecido dependente, uma vez que os mesmos resultados n??o foram observados no tecido card??aco dos animais.

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