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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.
31

Personal constructs of body-mind identity with persons who experience Medically Unexplained Symptoms (MUS)

Sanders, Tom January 2017 (has links)
Medically Unexplained Symptoms (MUS) are bodily symptoms for which no organic cause has been identified, and which result in significant levels of psychological distress and functional impairment. MUS are thought to be highly prevalent in primary care settings, and have considerable costs to society. Despite evidence of overlapping psychological and physical presentations, MUS are not well understood or treated in culture that predominantly views the body through the lenses of dualism and mechanistic reductionism. An alternative 'interactive' view of the body as playing a more dynamic role is elaborated through George Kelly's (1955) Personal Construct Psychology. The author draws upon Lin & Payne's (2014) 'frozen construing' theory, and empirical literature on relationships between identity and MUS, to suggest that for people with MUS, the symptomatic body is distressing because the person is struggling to integrate its meaning with their identity. It is hypothesized that embodied processes, that may actually protect the self (and others who share a construct system with that person) from events which threaten to dramatically alter how the self is construed, are difficult to understand because of their preverbal nature. Hence symptoms, and the body itself, are dissociated from the person's more elaborated verbal self-constructions. Several hypotheses relating to this suggestion were tested using a modified form of the repertory grid technique that was designed to explore construct systems of both mind and body, for self and others. Twenty participants with MUS, recruited from the community, completed the repertory grid interviews and measures of depression, anxiety and symptom severity, which were correlated with relevant repertory grid indices to test hypotheses. Findings indicated that symptom constructs, contrary to expectations, were well integrated into participants' construct systems. The alleviation of psychological distress was significantly associated with increased perceived distance between the self in general and the self when symptoms are worst (a relationship which appeared to be independent of severity of symptoms), providing evidence of a process of dissociation that protected the current self from assimilating the undesirable characteristics that were associated with the symptom. The way in which the self when symptoms are worst is construed appeared to influence levels of distress, with more predictive power than several other indices. The study also found evidence for some participants of hypothesized relationships between desired aspects of the current self and symptoms, that would imply that symptom disappearance would actually threaten a desirable aspect of how the self is construed. Content analysis of these constructs revealed (as predicted) that such desirable aspects of self tended to relate to being responsible and sensitive to the needs of others, and were elaborated through bodily constructs in a way that suggested that they were not well integrated with the primary ways that these participants made sense of their identity. For these particular participants, discrepancies between the ideals that they had for themselves, and how they would like to be seen by others, were associated with increased depression. Several participants were identified whose constructions of self and others were dominated by constructs relating to both mental and physical strength and weakness. These participants appeared to be struggling to find coherent meaning for themselves as the result of symptoms, which were regarded as invalidating a pre-symptom construal of themselves as being 'strong'. There seemed to be a continuum of being a 'body for others' on the one hand, a previously 'strong person' on the other, and a person who is 'strong for others' in the middle. Implications for clinical practice are discussed. Although the findings of the current study are limited by a small sample size, it appears that exploring the meaning of the body in the construction of self helps to elaborate the meaning of the body and symptoms in a verbal, expressible form. This process is likely to be helpful to those who struggle to find meanings for their symptoms both in their own construct systems and in a society that objectifies the body.
32

Identification de facteurs génétiques contrôlant la résistance de lignées de souris consanguines à une infection expérimentale par Yersinia pestis, l'agent de la peste

Blanchet, Charlène 20 November 2009 (has links) (PDF)
La peste est une zoonose touchant principalement les rongeurs et de façon accidentelle l'Homme. L'agent responsable de la peste bubonique et pulmonaire est la bactérie Gram négative Yersinia pestis. Les mécanismes qui permettent à l'hôte de résister ou non à cette infection sont mal connus. Nous avons montré que certaines lignées consanguines de souris, comme C57BL/6J, meurent après l'injection sous cutanée de 100 bactéries d'une souche virulente (CO92) alors que d'autres, comme SEG/Pas, dérivée de Mus spretus, résistent. Un croisement en retour entre ces deux lignées a permis d'identifier, sur les chromosomes 3, 4 et 6, trois QTLs contrôlant le taux de survie. Les deux premiers ont été retrouvés uniquement chez les femelles alors que celui du chromosome 6 est commun aux deux sexes. Des souris congéniques portant le chromosome 6 de SEG dans un fonds génétique C57BL/6J ont été produites. Après infection, elles meurent dans les mêmes proportions que les souris C57BL/6, mais un peu plus tardivement. Des souris bi- et tri-congéniques sont en cours de production pour tester l'effet des autres QTLs. Nous avons testé une collection de 55 lignées recombinantes congéniques interspécifiques entre SEG/Pas et C57BL/6J. Plusieurs lignées ont montré des différences de taux ou de durée de survie significatives par rapport à C57BL/6J. L'étude de la lignée 120G, qui meurt plus rapidement que C57BL/6J, suggère que la région proximale du chromosome 6 serait responsable de ce phénotype. Nous avons ainsi montré que le contrôle génétique de la résistance à la peste chez les souris SEG/Pas est complexe, et identifié plusieurs régions génomiques qui jouent un rôle important dans ce phénotype.
33

Causes and Consequences of Cooperative Construction in the Mice Mus spicilegus and Peromyscus polionotus

Tong, Wenfei 14 March 2013 (has links)
The cooperative construction of shared dwellings is a phylogenetically-widespread evolutionary puzzle. Shared shelters are common goods – all individuals in the shelter benefit, at the expense of those individuals that contribute to the construction. The evolution of cooperation requires existing variation for selection to act upon and genetic benefits to cooperators, through inclusive fitness or direct rewards. This study focuses on two genera of mice, Mus and Peromyscus, to examine shared construction and social monogamy as potential transitions to more sophisticated forms of sociality, such as cooperative breeding. The mound-building mouse (Mus spicilegus) is named for the large mounds that groups of mice build and beneath which they overwinter. Variation in mtDNA and 14 microsatellites show limited genetic structure across the geographic range of M. spicilegus. Mice from the same mound are more genetically related than mice from different mounds, and males and females associated with a mound are equally likely to be relatives. However in spring, when breeding begins, male kin are more likely to share a territory than are female kin. One possible interpretation is that males associate with kin to minimize the costs of being cuckolded, as this study finds evidence of multiple paternity in every litter genotyped. By increasing the chances of the cuckold being a brother, a male still gains inclusive fitness benefits from paternal care to extra-pair offspring in this socially monogamous species. Behavioral experiments show that another socially monogamous mouse species, the oldfield mouse (Peromyscus polionotus), can coordinate construction with unfamiliar, unrelated conspecifics. In contrast, two other closely related Peromyscus species do not dig longer burrows in pairs than they would have as individuals. Male-female P. polionotus pairs tend to dig longer burrows than pairs of the same sex, but males within opposite sex pairs do most of the digging, particularly when paired with an unfamiliar female. Male burrowing could be the product of female choice in this monogamous species. In M. spicilegus and P. polionotus, shared parental care and construction shed light on the evolution of cooperation and conflict.
34

The mystery of the Mystery sonatas : a musical rosary picture book

Strieck, Katia. January 1999 (has links)
Heinrich Ignaz Franz von Biber's (1644--1704) Mystery Sonatas of 1676 are a set of fifteen sonatas for violin and continuo plus one unaccompanied passacaglia for solo violin. They are unusual in their use of scordatura and in the presence of an image associated with the Rosary devotion before each sonata. This association between image and music in the sonatas, and the correspondence to the fifteen mysteries of the Rosary closely resembles the structure of seventeenth-century Rosary picture books. / In this thesis the context, background, and meaning of the sonatas is explored. The first chapter examines the function of the sonatas and places them in context by outlining musical life in Salzburg, the sonata tradition, the Rosary devotion, Emblem books, and Rosary picture books. The second chapter focuses more on the collection as a whole and on elements such as key, dance affect, and scordatura. The third chapter consists of an examination of three sonatas---each one unique in placing the listener in a different relation to the mystery.
35

Vitrificação de embriões Mus domesticus domesticus envasados em palheta convencional dotada de haste metálica. / Mus domesticus domesticus embryo vitrification using original straws containing a metallic stick

Costa, Alexandre Aiquel Vaz January 2007 (has links)
O objetivo deste experimento foi determinar a sobrevivência de blastocistos Mus domesticus domesticus vitrificado em palhetas na presença de uma haste metálica .Blastocistos Mus domesticus domesticus coletados no quarto dia após a fecundação, foram avaliados morfologicamente e divididos aleatoriamente em três grupos. Os embriões do grupo controle foram transferidos para gotas de meio KSOM e cultivados in vitro por 48 horas. Os embriões selecionados para criopreservação foram expostos a uma solução crioprotetora constituída por PBSm + de 10% etileno-glicol + 10% propileno-glicol, para promover uma desidratação das células embrionárias. Após foram transferidos para a solução de vitrificação que continha 20% etilenoglicol + 20% propilenoglicol diluídos em PBSm, e mantidos durante 25 segundos, sendo imediatamente imersos em nitrogênio submetido à vácuo. As taxas de sobrevivência embrionária revelaram uma maior eficiência da técnica com a inserção da peça metálica (56,21% - 86/153) em relação ao método convencional (18,84% - 26/138). Concluímos assim que a presença da peça metálica em contato com a amostra propiciou maior taxa de sobrevivência dos embriões submetidos à vitrificação envasados em palhetas de 0,25 mL. / The aim of this experiment was determine the Mus domesticus domesticus blastocysts survival rates after vitrification in straws containing a metallic stick, that allows to increase the temperature changes among the nitrogen and the embryo sample. Day 4 Mus domesticus domesticus blastocysts were collected from superovulated donnors and after morphologically evaluation were randomly divided in three groups. The embryos select as control group were transferred to KSOM medium drops and in vitro cultured during 48 hours. The crioperservation selected embryos were first exposed to a cryoprotective solution (modified PBS + 10% ethylene-glycol and 10% propylene-glycol) to promote embryo cell dehydration and after exposed during 25 seconds to the vitrification solution composed by modified PBS + 20% ethylene-glycol and 20% propylene-glycol, and immediately plunged into slush liquid nitrogen. The embryo survival rate in group vitrified in the straws containing the metallic stick (56,21% - 86/153) was significantly different from the observed in the group loaded in original straws (18,84% - 26/138). In conclusion, the presence of the metallic stick in contact with the sample was efficient to enhance more suitable survival rates after vitrification of Mus domesticus domesticus blastocysts loaded in 0,25 mL straws.
36

Sobrevivência in vitro de blastocistos Mus domesticus domesticus vitrificados em macro ou microvolume de crioprotetor.

Osuna, Alexander Nivia January 2008 (has links)
O desenvolvimento de protocolos eficientes para a vitrificação de embriões mamíferos ainda é um desafio para os especialistas em reprodução. Soluções crioprotetoras de baixa toxicidade associadas a técnicas seguras de envase são fatores fundamentais, para proporcionarem uma eficiente identificação e controle sanitário das amostras. Dois experimentos foram realizados para determinar a taxa de sobrevivência de embriões Mus domesticus domesticus envasados em palhetas convencionais (0,25 mL), na presença de uma haste metálica de ouro, empregando soluções crioprotetoras descritas para a vitrificação em microvolume. No experimento 1, avaliou-se a toxicidade da solução de desidratação (SD: PBSm + 10% EG + 10% PROH + 0,5 M sacarose), expondo-se os embriões por diferentes tempos: 1 (T1), 3 (T2) ou 10 min (T3). A toxicidade da solução de vitrificação (SV: PBSm + 20% EG + 20% PROH) foi determinada pela exposição dos embriões durante 25, 60 ou 180 seg, previamente desidratados por 1 ou 3 min. No experimento 2, avaliou-se a utilização do macrovolume (palhetas com a haste de ouro) e microvolume (micropipetas de vidro - GMP) na vitrificação dos blastocistos expostos à SV por 25 seg, previamente desidratados por 1 ou 3 min. Os dados foram analisados pelo teste Qui-Quadrado (P<0,05). No experimento 1, não foi observada diferença estatística entre as taxas de eclosão dos embriões desidratados: T1=68,0% (38/56), T2=72,0% (36/50), T3=71,0% (39/55) e o grupo controle, (74,0% - 48/65). No entanto, houve diferença significativa (P<0,05) na taxa de eclosão em relação ao tempo de exposição dos embriões à SV. Os embriões desidratados por 1 ou 3 min e expostos à SV por 25 seg proporcionaram maiores taxas de re-expansão (79,0% vs 84,0%) e de eclosão (58,0% vs 72,0%), em relação aos tempos de exposição de 60 e 180 seg. No experimento 2, após a vitrificação dos embriões envasados nas palhetas com a haste de ouro, a taxa de eclosão dos blastocistos previamente desidratados por 1 min foi de 16,0% (10/64) e de 4,0% (2/57) quando previamente desidratados por 3 min. Por outro lado, os embriões envasados nas GMP, e previamente desidratados por 3 min, foram os que apresentaram maior taxa de eclosão (60,0% - 52/86). A vitrificação de embriões utilizando soluções crioprototetoras descritas para microvolume não foi eficiente na crioproteção dos blastocistos envasados em palhetas convencionais com a haste de ouro. / The development of efficient vitrification protocols for mammalian embryos still is a challenge for reproductive biologists. Low toxicity cryoprotectant solutions and safe vitrifications procedures that allow sample identification and sanitary control are fundamental factors. Two experiments were conducted to determine the survival rate of vitrified Mus domesticus domesticus embryos loaded into straws containing a metallic piece (manufactured in gold), using cryoprotectant solutions described for microvolume vitrification procedures. In Experiment 1, the toxicity of the dehydratation solution (SD: PBSm +10% EG + 10% PROH + 0,5 M sucrose) was evaluated using three different embryo exposure times: 1 (T1), 3 (T2) or 10 min (T3), in addition as well as the toxicity of the vitrification solution (SV: PBSm + 20% EG + 20% PROH) was also tested upon embryo exposure for 25, 60 or 180 sec, previously dehydration for 1 or 3 min. In Experiment 2, the use of macrovolume (straw with a stem of gold) or microvolume (glass micropipettes – GMP) was evaluated for the vitrification of blastocysts after exposure to SV for 25 sec and previous dehydration for 1 or 3 min. Data were analized by the Chi-square test (P<0,05). In Experiment 1, statistical differences were not observed between hatching rates of dehydrated embryos: T1=68.0% (38/56), T2=72.0% (36/50), T3=71.0% (39/55) and control group embryos, (74.0% - 48/65). However, a significant difference (P <0,05) was observed between hatching rates after embryos exposure to the SV. Embryos dehydrated for 1 or 3 min and exposed for 25 sec to the SV showed higher re-expansion (79.0% vs. 84.0%) and hatching rates (58.0% vs. 72.0%) than embryos exposed to SV for 60 or 180 sec. In Experiment 2, after vitrification of the embryos loaded into straws containing a metallic piece showed a hatching rate of 16.0% (10/64) when previouslly dehydrated for 1 min, and 4.0% (2/57) when for 3 min. On the other hand, embryos loaded into GMP, previouslly dehydrated for 3 min, showed a higher hatching rate, (60.0% - 52/60). Embryo vitrification using a cryoprotectant solution described as suitable for microvolume was not efficient to cryoprotect blastocysts loaded into macrovolume straws containing a metallic piece.
37

Vitrificação de embriões Mus domesticus domesticus envasados em palheta convencional dotada de haste metálica. / Mus domesticus domesticus embryo vitrification using original straws containing a metallic stick

Costa, Alexandre Aiquel Vaz January 2007 (has links)
O objetivo deste experimento foi determinar a sobrevivência de blastocistos Mus domesticus domesticus vitrificado em palhetas na presença de uma haste metálica .Blastocistos Mus domesticus domesticus coletados no quarto dia após a fecundação, foram avaliados morfologicamente e divididos aleatoriamente em três grupos. Os embriões do grupo controle foram transferidos para gotas de meio KSOM e cultivados in vitro por 48 horas. Os embriões selecionados para criopreservação foram expostos a uma solução crioprotetora constituída por PBSm + de 10% etileno-glicol + 10% propileno-glicol, para promover uma desidratação das células embrionárias. Após foram transferidos para a solução de vitrificação que continha 20% etilenoglicol + 20% propilenoglicol diluídos em PBSm, e mantidos durante 25 segundos, sendo imediatamente imersos em nitrogênio submetido à vácuo. As taxas de sobrevivência embrionária revelaram uma maior eficiência da técnica com a inserção da peça metálica (56,21% - 86/153) em relação ao método convencional (18,84% - 26/138). Concluímos assim que a presença da peça metálica em contato com a amostra propiciou maior taxa de sobrevivência dos embriões submetidos à vitrificação envasados em palhetas de 0,25 mL. / The aim of this experiment was determine the Mus domesticus domesticus blastocysts survival rates after vitrification in straws containing a metallic stick, that allows to increase the temperature changes among the nitrogen and the embryo sample. Day 4 Mus domesticus domesticus blastocysts were collected from superovulated donnors and after morphologically evaluation were randomly divided in three groups. The embryos select as control group were transferred to KSOM medium drops and in vitro cultured during 48 hours. The crioperservation selected embryos were first exposed to a cryoprotective solution (modified PBS + 10% ethylene-glycol and 10% propylene-glycol) to promote embryo cell dehydration and after exposed during 25 seconds to the vitrification solution composed by modified PBS + 20% ethylene-glycol and 20% propylene-glycol, and immediately plunged into slush liquid nitrogen. The embryo survival rate in group vitrified in the straws containing the metallic stick (56,21% - 86/153) was significantly different from the observed in the group loaded in original straws (18,84% - 26/138). In conclusion, the presence of the metallic stick in contact with the sample was efficient to enhance more suitable survival rates after vitrification of Mus domesticus domesticus blastocysts loaded in 0,25 mL straws.
38

Sobrevivência in vitro de blastocistos Mus domesticus domesticus vitrificados em macro ou microvolume de crioprotetor.

Osuna, Alexander Nivia January 2008 (has links)
O desenvolvimento de protocolos eficientes para a vitrificação de embriões mamíferos ainda é um desafio para os especialistas em reprodução. Soluções crioprotetoras de baixa toxicidade associadas a técnicas seguras de envase são fatores fundamentais, para proporcionarem uma eficiente identificação e controle sanitário das amostras. Dois experimentos foram realizados para determinar a taxa de sobrevivência de embriões Mus domesticus domesticus envasados em palhetas convencionais (0,25 mL), na presença de uma haste metálica de ouro, empregando soluções crioprotetoras descritas para a vitrificação em microvolume. No experimento 1, avaliou-se a toxicidade da solução de desidratação (SD: PBSm + 10% EG + 10% PROH + 0,5 M sacarose), expondo-se os embriões por diferentes tempos: 1 (T1), 3 (T2) ou 10 min (T3). A toxicidade da solução de vitrificação (SV: PBSm + 20% EG + 20% PROH) foi determinada pela exposição dos embriões durante 25, 60 ou 180 seg, previamente desidratados por 1 ou 3 min. No experimento 2, avaliou-se a utilização do macrovolume (palhetas com a haste de ouro) e microvolume (micropipetas de vidro - GMP) na vitrificação dos blastocistos expostos à SV por 25 seg, previamente desidratados por 1 ou 3 min. Os dados foram analisados pelo teste Qui-Quadrado (P<0,05). No experimento 1, não foi observada diferença estatística entre as taxas de eclosão dos embriões desidratados: T1=68,0% (38/56), T2=72,0% (36/50), T3=71,0% (39/55) e o grupo controle, (74,0% - 48/65). No entanto, houve diferença significativa (P<0,05) na taxa de eclosão em relação ao tempo de exposição dos embriões à SV. Os embriões desidratados por 1 ou 3 min e expostos à SV por 25 seg proporcionaram maiores taxas de re-expansão (79,0% vs 84,0%) e de eclosão (58,0% vs 72,0%), em relação aos tempos de exposição de 60 e 180 seg. No experimento 2, após a vitrificação dos embriões envasados nas palhetas com a haste de ouro, a taxa de eclosão dos blastocistos previamente desidratados por 1 min foi de 16,0% (10/64) e de 4,0% (2/57) quando previamente desidratados por 3 min. Por outro lado, os embriões envasados nas GMP, e previamente desidratados por 3 min, foram os que apresentaram maior taxa de eclosão (60,0% - 52/86). A vitrificação de embriões utilizando soluções crioprototetoras descritas para microvolume não foi eficiente na crioproteção dos blastocistos envasados em palhetas convencionais com a haste de ouro. / The development of efficient vitrification protocols for mammalian embryos still is a challenge for reproductive biologists. Low toxicity cryoprotectant solutions and safe vitrifications procedures that allow sample identification and sanitary control are fundamental factors. Two experiments were conducted to determine the survival rate of vitrified Mus domesticus domesticus embryos loaded into straws containing a metallic piece (manufactured in gold), using cryoprotectant solutions described for microvolume vitrification procedures. In Experiment 1, the toxicity of the dehydratation solution (SD: PBSm +10% EG + 10% PROH + 0,5 M sucrose) was evaluated using three different embryo exposure times: 1 (T1), 3 (T2) or 10 min (T3), in addition as well as the toxicity of the vitrification solution (SV: PBSm + 20% EG + 20% PROH) was also tested upon embryo exposure for 25, 60 or 180 sec, previously dehydration for 1 or 3 min. In Experiment 2, the use of macrovolume (straw with a stem of gold) or microvolume (glass micropipettes – GMP) was evaluated for the vitrification of blastocysts after exposure to SV for 25 sec and previous dehydration for 1 or 3 min. Data were analized by the Chi-square test (P<0,05). In Experiment 1, statistical differences were not observed between hatching rates of dehydrated embryos: T1=68.0% (38/56), T2=72.0% (36/50), T3=71.0% (39/55) and control group embryos, (74.0% - 48/65). However, a significant difference (P <0,05) was observed between hatching rates after embryos exposure to the SV. Embryos dehydrated for 1 or 3 min and exposed for 25 sec to the SV showed higher re-expansion (79.0% vs. 84.0%) and hatching rates (58.0% vs. 72.0%) than embryos exposed to SV for 60 or 180 sec. In Experiment 2, after vitrification of the embryos loaded into straws containing a metallic piece showed a hatching rate of 16.0% (10/64) when previouslly dehydrated for 1 min, and 4.0% (2/57) when for 3 min. On the other hand, embryos loaded into GMP, previouslly dehydrated for 3 min, showed a higher hatching rate, (60.0% - 52/60). Embryo vitrification using a cryoprotectant solution described as suitable for microvolume was not efficient to cryoprotect blastocysts loaded into macrovolume straws containing a metallic piece.
39

Vitrificação de embriões Mus domesticus domesticus envasados em palheta convencional dotada de haste metálica. / Mus domesticus domesticus embryo vitrification using original straws containing a metallic stick

Costa, Alexandre Aiquel Vaz January 2007 (has links)
O objetivo deste experimento foi determinar a sobrevivência de blastocistos Mus domesticus domesticus vitrificado em palhetas na presença de uma haste metálica .Blastocistos Mus domesticus domesticus coletados no quarto dia após a fecundação, foram avaliados morfologicamente e divididos aleatoriamente em três grupos. Os embriões do grupo controle foram transferidos para gotas de meio KSOM e cultivados in vitro por 48 horas. Os embriões selecionados para criopreservação foram expostos a uma solução crioprotetora constituída por PBSm + de 10% etileno-glicol + 10% propileno-glicol, para promover uma desidratação das células embrionárias. Após foram transferidos para a solução de vitrificação que continha 20% etilenoglicol + 20% propilenoglicol diluídos em PBSm, e mantidos durante 25 segundos, sendo imediatamente imersos em nitrogênio submetido à vácuo. As taxas de sobrevivência embrionária revelaram uma maior eficiência da técnica com a inserção da peça metálica (56,21% - 86/153) em relação ao método convencional (18,84% - 26/138). Concluímos assim que a presença da peça metálica em contato com a amostra propiciou maior taxa de sobrevivência dos embriões submetidos à vitrificação envasados em palhetas de 0,25 mL. / The aim of this experiment was determine the Mus domesticus domesticus blastocysts survival rates after vitrification in straws containing a metallic stick, that allows to increase the temperature changes among the nitrogen and the embryo sample. Day 4 Mus domesticus domesticus blastocysts were collected from superovulated donnors and after morphologically evaluation were randomly divided in three groups. The embryos select as control group were transferred to KSOM medium drops and in vitro cultured during 48 hours. The crioperservation selected embryos were first exposed to a cryoprotective solution (modified PBS + 10% ethylene-glycol and 10% propylene-glycol) to promote embryo cell dehydration and after exposed during 25 seconds to the vitrification solution composed by modified PBS + 20% ethylene-glycol and 20% propylene-glycol, and immediately plunged into slush liquid nitrogen. The embryo survival rate in group vitrified in the straws containing the metallic stick (56,21% - 86/153) was significantly different from the observed in the group loaded in original straws (18,84% - 26/138). In conclusion, the presence of the metallic stick in contact with the sample was efficient to enhance more suitable survival rates after vitrification of Mus domesticus domesticus blastocysts loaded in 0,25 mL straws.
40

Sobrevivência in vitro de blastocistos Mus domesticus domesticus vitrificados em macro ou microvolume de crioprotetor.

Osuna, Alexander Nivia January 2008 (has links)
O desenvolvimento de protocolos eficientes para a vitrificação de embriões mamíferos ainda é um desafio para os especialistas em reprodução. Soluções crioprotetoras de baixa toxicidade associadas a técnicas seguras de envase são fatores fundamentais, para proporcionarem uma eficiente identificação e controle sanitário das amostras. Dois experimentos foram realizados para determinar a taxa de sobrevivência de embriões Mus domesticus domesticus envasados em palhetas convencionais (0,25 mL), na presença de uma haste metálica de ouro, empregando soluções crioprotetoras descritas para a vitrificação em microvolume. No experimento 1, avaliou-se a toxicidade da solução de desidratação (SD: PBSm + 10% EG + 10% PROH + 0,5 M sacarose), expondo-se os embriões por diferentes tempos: 1 (T1), 3 (T2) ou 10 min (T3). A toxicidade da solução de vitrificação (SV: PBSm + 20% EG + 20% PROH) foi determinada pela exposição dos embriões durante 25, 60 ou 180 seg, previamente desidratados por 1 ou 3 min. No experimento 2, avaliou-se a utilização do macrovolume (palhetas com a haste de ouro) e microvolume (micropipetas de vidro - GMP) na vitrificação dos blastocistos expostos à SV por 25 seg, previamente desidratados por 1 ou 3 min. Os dados foram analisados pelo teste Qui-Quadrado (P<0,05). No experimento 1, não foi observada diferença estatística entre as taxas de eclosão dos embriões desidratados: T1=68,0% (38/56), T2=72,0% (36/50), T3=71,0% (39/55) e o grupo controle, (74,0% - 48/65). No entanto, houve diferença significativa (P<0,05) na taxa de eclosão em relação ao tempo de exposição dos embriões à SV. Os embriões desidratados por 1 ou 3 min e expostos à SV por 25 seg proporcionaram maiores taxas de re-expansão (79,0% vs 84,0%) e de eclosão (58,0% vs 72,0%), em relação aos tempos de exposição de 60 e 180 seg. No experimento 2, após a vitrificação dos embriões envasados nas palhetas com a haste de ouro, a taxa de eclosão dos blastocistos previamente desidratados por 1 min foi de 16,0% (10/64) e de 4,0% (2/57) quando previamente desidratados por 3 min. Por outro lado, os embriões envasados nas GMP, e previamente desidratados por 3 min, foram os que apresentaram maior taxa de eclosão (60,0% - 52/86). A vitrificação de embriões utilizando soluções crioprototetoras descritas para microvolume não foi eficiente na crioproteção dos blastocistos envasados em palhetas convencionais com a haste de ouro. / The development of efficient vitrification protocols for mammalian embryos still is a challenge for reproductive biologists. Low toxicity cryoprotectant solutions and safe vitrifications procedures that allow sample identification and sanitary control are fundamental factors. Two experiments were conducted to determine the survival rate of vitrified Mus domesticus domesticus embryos loaded into straws containing a metallic piece (manufactured in gold), using cryoprotectant solutions described for microvolume vitrification procedures. In Experiment 1, the toxicity of the dehydratation solution (SD: PBSm +10% EG + 10% PROH + 0,5 M sucrose) was evaluated using three different embryo exposure times: 1 (T1), 3 (T2) or 10 min (T3), in addition as well as the toxicity of the vitrification solution (SV: PBSm + 20% EG + 20% PROH) was also tested upon embryo exposure for 25, 60 or 180 sec, previously dehydration for 1 or 3 min. In Experiment 2, the use of macrovolume (straw with a stem of gold) or microvolume (glass micropipettes – GMP) was evaluated for the vitrification of blastocysts after exposure to SV for 25 sec and previous dehydration for 1 or 3 min. Data were analized by the Chi-square test (P<0,05). In Experiment 1, statistical differences were not observed between hatching rates of dehydrated embryos: T1=68.0% (38/56), T2=72.0% (36/50), T3=71.0% (39/55) and control group embryos, (74.0% - 48/65). However, a significant difference (P <0,05) was observed between hatching rates after embryos exposure to the SV. Embryos dehydrated for 1 or 3 min and exposed for 25 sec to the SV showed higher re-expansion (79.0% vs. 84.0%) and hatching rates (58.0% vs. 72.0%) than embryos exposed to SV for 60 or 180 sec. In Experiment 2, after vitrification of the embryos loaded into straws containing a metallic piece showed a hatching rate of 16.0% (10/64) when previouslly dehydrated for 1 min, and 4.0% (2/57) when for 3 min. On the other hand, embryos loaded into GMP, previouslly dehydrated for 3 min, showed a higher hatching rate, (60.0% - 52/60). Embryo vitrification using a cryoprotectant solution described as suitable for microvolume was not efficient to cryoprotect blastocysts loaded into macrovolume straws containing a metallic piece.

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