• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 47
  • 8
  • 7
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 94
  • 13
  • 12
  • 11
  • 10
  • 9
  • 9
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • 7
  • 7
  • 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.
71

Hemodinâmica uterina avaliada por ultrassom Doppler colorido e taxa de fertilidade de vacas submetidas à IATF com sêmen analisado por sondas fluorescentes / Uterine hemodynamics assessed by color Doppler ultrasound and fertility rate of cows submitted to FTAI with semen analyzed by fluorescent probes

Oliveira, Bruna Marcele Martins de 31 January 2012 (has links)
Após a inseminação artificial, as fêmeas apresentam reação inflamatória transitória e fisiológica, que pode resultar em alterações na vascularização uterina. A ultrassonografia Doppler colorido é uma técnica não invasiva, que vem sendo utilizada para estudar a hemodinâmica do trato reprodutivo de bovinos. Os objetivos deste trabalho foram verificar a resposta inflamatória uterina por ultrassonografia Doppler colorido e a taxa de fertilidade em bovinos após inseminação artificial (IA) com sêmen avaliado por sondas fluorescentes. Para isso foram delineados dois experimentos. O experimento 1 foi realizado para estudar a hemodinâmica uterina por ultrassonografia Doppler colorido em bovinos após a IA. Foram utilizadas 18 vacas da raça Nelore, submetidas a um protocolo para a inseminação artificial em tempo fixo (IATF) e divididas em dois grupos: Grupo não inseminado (controle, GC, n=9) e grupo submetido à inseminação artificial (GIA, n=9). Avaliações por ultrassonografia foram realizadas em cinco momentos em modo espectral (30 horas antes da IA, 4, 24, 48 e 168 horas após a IA) para avaliar o índice de resistência (RI) da artéria uterina e em quatro momentos em modo color Doppler (4, 24, 48 e 168 horas após a IA) para avaliar a vascularização dos cornos uterinos. O diagnóstico de gestação foi feito após 30 dias da IA. No experimento 2 objetivou-se verificar se o percentual de espermatozóides com integridade das membranas plasmática e acrossomal e função mitocondrial (PIAIC) avaliadas por sondas fluorescentes influencia a fertilidade e estudar a hemodinâmica uterina após a deposição do sêmen com diferentes percentuais de espermatozóides PIAIC. Foram utilizadas 182 vacas paridas da raça Nelore, submetidas a um protocolo para IATF e divididas em três grupos de acordo com a qualidade do sêmen: Bom (B) 44,5%, Médio (M) 23% e Regular (R) 8,5% de espermatozóides PIAIC/palheta. Uma amostra de 30% das fêmeas (54, sendo 18 de cada grupo) foram submetidas a avaliações com ultrassonografia Doppler colorido 30 horas antes da IA, 4 e 24 horas após a IA. Foram considerados os RI das artérias uterinas direita (AD) e esquerda (AE) e vascularização subjetiva dos cornos uterinos direito (CD) e esquerdo (CE). Posteriormente, foram separados levando em consideração o lado do ovário contendo o folículo dominante para comparar RI das artérias ipsi (AI) e contralateral (AC) e vascularização subjetiva dos cornos uterinos ipsi (CI) e contralateral (CC). O diagnóstico de gestação foi realizado 30 dias após a IA. Para a análise estatística foi utilizado o programa SAS versão 9.2 (SAS 2010). As variáveis foram analisadas pelo PROC MIXED, utilizando modelo linear misto para medidas repetidas no tempo. Foram considerados os efeitos fixos de grupo, tempo e interação grupo x tempo. Os dados obtidos foram submetidos à análise de variância e ao teste de Duncan, pelo PROC GLM. A análise de Qui-Quadrado foi utilizada para determinar a taxa de prenhez, de acordo com a qualidade do sêmen pelo PROC FREQ. O nível de significância considerado foi de 5%. No experimento 1 não foram observadas diferenças dos parâmetros avaliados por ultrassom Doppler entre GIA e GC, mas foram notados efeitos do tempo para RI, sendo mais baixos 4 horas após a IA. Quando os dados foram avaliados de acordo com o lado do folículo dominante foi observado que 4 e 24 horas após a IA, RI da AC do GIA foi mais baixo do que o GC. No experimento 2 não houve diferença entre os animais inseminados com sêmen B, M ou R quanto a hemodinâmica uterina, mas houve efeito do tempo, sendo que 4 horas após a IA verificou-se menor valor de RI e maior fluxo sanguíneo. A taxa de prenhez dos animais inseminados com o sêmen B (64,7%) foi maior quando comparada ao sêmen R (36,2%), sendo que ambos não diferiram do sêmen M (50,0%). Pode-se concluir que não é possível detectar por ultrassonografia Doppler alterações na hemodinâmica uterina devido à IA em fêmeas bovinas. A deposição de sêmen com diferentes qualidades não altera a hemodinâmica uterina de forma detectável por ultrassonografia Doppler em bovinos. Por outro lado, é possível detectar por ultrassonografia Doppler mudanças na perfusão sanguínea do útero em relação ao tempo da IA, o que pode ser devido a alterações hormonais que ocorrem durante o ciclo estral. Por fim, a IA com sêmen contendo menor percentual de espermatozoides PIAIC causa redução na taxa de fertilidade em bovinos. / After insemination, females have physiological and transient inflammatory reaction, which can result in changes in the uterine vasculature. The color Doppler ultrasound is a noninvasive technique that has been used to study the hemodynamics of cattle reproductive tract.The purposes of this work were to verify uterine inflammatory response by color Doppler ultrasound and fertility rate in cattle after artificial insemination (IA) with semen evaluated by fluorescent probes. For this, two experiments were delineated. The first experiment was conducted to study the uterine hemodynamic by color Doppler ultrasound in cattle after AI. Were used 18 Nellore cows that were subjected to a protocol for fixed timed artificial insemination (IATF). The animals were divided in two groups: Not inseminated group (control, GC, n=9) and inseminated group (GIA, n=9). Ultrasonografic evaluation were done in five moments on spectral mode (30 hours before AI, 4, 24, 48 e 168 hours after IA) to evaluate the resistence index (RI) of uterine artery and in four moments in color Doppler mode to evaluate the uterine horns vascularization. The pregnancy diagnostic was done 30 days after IA. In the second experiment the objective was to evaluate whether the percentage of sperm with plasma membrane integrity and acrossomal and mitochondrial function (PIAIC) assessed by fluorescent probes influences fertility and study the uterine hemodynamic after the deposition of semen with different percentages of PIAIC sperm. Were used 182 caved Nellore cows submitted to a protocol for IATF and divided into three groups according to semen quality: Good (B) 44.5%, Medium (M) 23% and Regular (R) 8,5% of PIAIC sperm/blade. A sample of 30% of female (54, 18 in each group) were submitted to evaluation by color Doppler ultrasound 30 hours before IA, 4 and 24 hours after IA. Were considered RI of right (AD) and left (AE) uterine arteries and subjective vascularization of right (CD) and left (CE) uterine horns. Later, they were separated taking into account the side of the ovary containing the dominant follicle to compare RI of ipsi (AI) and contralateral (AC) arteries and subjective vascularization of ipsi (CI) and contralateral (CC) uterine horns. The pregnancy diagnostic was done 30 days after IA. Statistical analysis was performed using the program SAS version 9.2 (SAS 2010). The variables were analyzed by PROC MIXED, using mixed linear model for repeated measures in time. We considered effects of group, time and group x time interaction. The data obtained were submitted to ANOVA and Duncan test, using PROC GLM. The chi-square analysis was used to determine pregnancy rate, according to the quality of semen by PROC FREQ. the significance level was 5%. In experiment 1 there were no differences of the parameters evaluated by Doppler ultrasound between GIA and GC, but time effects were noted for RI, it was lower four hours after IA. When the data were evaluated according to the side of the dominant follicle was observed that 4 and 24 hours after IA, RI of AC of GIA was lower when it was compared with GC. In experiment 2 there was no difference between animals inseminated with semen B, M or R about uterine hemodynamics, but there were effects of time, so that 4 hours after IA showed lower value of RI and increased blood flow. The pregnancy rate of animals inseminated with semen B (64.7%) was higher when compared with semen R (36.2%), both of them did not differ of semen M (50.0%). It can be concluded that is not possible to detect uterine hemodynamic changes by Doppler ultrasound due to IA in cattle. The deposition of semen with different qualities does not change the uterine hemodynamics enough to be detectable by Doppler ultrasonography in cattle. On the other hand, is possible to detect changes in blood perfusion of the uterus in relation to the time of IA by Doppler ultrasound, which may be due to hormonal changes that occur during the estrous cycle. Finally, IA with semen containing a lower percentage of PIAIC sperm causes a reduction in fertility rate in cattle.
72

Hemodinâmica uterina avaliada por ultrassom Doppler colorido e taxa de fertilidade de vacas submetidas à IATF com sêmen analisado por sondas fluorescentes / Uterine hemodynamics assessed by color Doppler ultrasound and fertility rate of cows submitted to FTAI with semen analyzed by fluorescent probes

Bruna Marcele Martins de Oliveira 31 January 2012 (has links)
Após a inseminação artificial, as fêmeas apresentam reação inflamatória transitória e fisiológica, que pode resultar em alterações na vascularização uterina. A ultrassonografia Doppler colorido é uma técnica não invasiva, que vem sendo utilizada para estudar a hemodinâmica do trato reprodutivo de bovinos. Os objetivos deste trabalho foram verificar a resposta inflamatória uterina por ultrassonografia Doppler colorido e a taxa de fertilidade em bovinos após inseminação artificial (IA) com sêmen avaliado por sondas fluorescentes. Para isso foram delineados dois experimentos. O experimento 1 foi realizado para estudar a hemodinâmica uterina por ultrassonografia Doppler colorido em bovinos após a IA. Foram utilizadas 18 vacas da raça Nelore, submetidas a um protocolo para a inseminação artificial em tempo fixo (IATF) e divididas em dois grupos: Grupo não inseminado (controle, GC, n=9) e grupo submetido à inseminação artificial (GIA, n=9). Avaliações por ultrassonografia foram realizadas em cinco momentos em modo espectral (30 horas antes da IA, 4, 24, 48 e 168 horas após a IA) para avaliar o índice de resistência (RI) da artéria uterina e em quatro momentos em modo color Doppler (4, 24, 48 e 168 horas após a IA) para avaliar a vascularização dos cornos uterinos. O diagnóstico de gestação foi feito após 30 dias da IA. No experimento 2 objetivou-se verificar se o percentual de espermatozóides com integridade das membranas plasmática e acrossomal e função mitocondrial (PIAIC) avaliadas por sondas fluorescentes influencia a fertilidade e estudar a hemodinâmica uterina após a deposição do sêmen com diferentes percentuais de espermatozóides PIAIC. Foram utilizadas 182 vacas paridas da raça Nelore, submetidas a um protocolo para IATF e divididas em três grupos de acordo com a qualidade do sêmen: Bom (B) 44,5%, Médio (M) 23% e Regular (R) 8,5% de espermatozóides PIAIC/palheta. Uma amostra de 30% das fêmeas (54, sendo 18 de cada grupo) foram submetidas a avaliações com ultrassonografia Doppler colorido 30 horas antes da IA, 4 e 24 horas após a IA. Foram considerados os RI das artérias uterinas direita (AD) e esquerda (AE) e vascularização subjetiva dos cornos uterinos direito (CD) e esquerdo (CE). Posteriormente, foram separados levando em consideração o lado do ovário contendo o folículo dominante para comparar RI das artérias ipsi (AI) e contralateral (AC) e vascularização subjetiva dos cornos uterinos ipsi (CI) e contralateral (CC). O diagnóstico de gestação foi realizado 30 dias após a IA. Para a análise estatística foi utilizado o programa SAS versão 9.2 (SAS 2010). As variáveis foram analisadas pelo PROC MIXED, utilizando modelo linear misto para medidas repetidas no tempo. Foram considerados os efeitos fixos de grupo, tempo e interação grupo x tempo. Os dados obtidos foram submetidos à análise de variância e ao teste de Duncan, pelo PROC GLM. A análise de Qui-Quadrado foi utilizada para determinar a taxa de prenhez, de acordo com a qualidade do sêmen pelo PROC FREQ. O nível de significância considerado foi de 5%. No experimento 1 não foram observadas diferenças dos parâmetros avaliados por ultrassom Doppler entre GIA e GC, mas foram notados efeitos do tempo para RI, sendo mais baixos 4 horas após a IA. Quando os dados foram avaliados de acordo com o lado do folículo dominante foi observado que 4 e 24 horas após a IA, RI da AC do GIA foi mais baixo do que o GC. No experimento 2 não houve diferença entre os animais inseminados com sêmen B, M ou R quanto a hemodinâmica uterina, mas houve efeito do tempo, sendo que 4 horas após a IA verificou-se menor valor de RI e maior fluxo sanguíneo. A taxa de prenhez dos animais inseminados com o sêmen B (64,7%) foi maior quando comparada ao sêmen R (36,2%), sendo que ambos não diferiram do sêmen M (50,0%). Pode-se concluir que não é possível detectar por ultrassonografia Doppler alterações na hemodinâmica uterina devido à IA em fêmeas bovinas. A deposição de sêmen com diferentes qualidades não altera a hemodinâmica uterina de forma detectável por ultrassonografia Doppler em bovinos. Por outro lado, é possível detectar por ultrassonografia Doppler mudanças na perfusão sanguínea do útero em relação ao tempo da IA, o que pode ser devido a alterações hormonais que ocorrem durante o ciclo estral. Por fim, a IA com sêmen contendo menor percentual de espermatozoides PIAIC causa redução na taxa de fertilidade em bovinos. / After insemination, females have physiological and transient inflammatory reaction, which can result in changes in the uterine vasculature. The color Doppler ultrasound is a noninvasive technique that has been used to study the hemodynamics of cattle reproductive tract.The purposes of this work were to verify uterine inflammatory response by color Doppler ultrasound and fertility rate in cattle after artificial insemination (IA) with semen evaluated by fluorescent probes. For this, two experiments were delineated. The first experiment was conducted to study the uterine hemodynamic by color Doppler ultrasound in cattle after AI. Were used 18 Nellore cows that were subjected to a protocol for fixed timed artificial insemination (IATF). The animals were divided in two groups: Not inseminated group (control, GC, n=9) and inseminated group (GIA, n=9). Ultrasonografic evaluation were done in five moments on spectral mode (30 hours before AI, 4, 24, 48 e 168 hours after IA) to evaluate the resistence index (RI) of uterine artery and in four moments in color Doppler mode to evaluate the uterine horns vascularization. The pregnancy diagnostic was done 30 days after IA. In the second experiment the objective was to evaluate whether the percentage of sperm with plasma membrane integrity and acrossomal and mitochondrial function (PIAIC) assessed by fluorescent probes influences fertility and study the uterine hemodynamic after the deposition of semen with different percentages of PIAIC sperm. Were used 182 caved Nellore cows submitted to a protocol for IATF and divided into three groups according to semen quality: Good (B) 44.5%, Medium (M) 23% and Regular (R) 8,5% of PIAIC sperm/blade. A sample of 30% of female (54, 18 in each group) were submitted to evaluation by color Doppler ultrasound 30 hours before IA, 4 and 24 hours after IA. Were considered RI of right (AD) and left (AE) uterine arteries and subjective vascularization of right (CD) and left (CE) uterine horns. Later, they were separated taking into account the side of the ovary containing the dominant follicle to compare RI of ipsi (AI) and contralateral (AC) arteries and subjective vascularization of ipsi (CI) and contralateral (CC) uterine horns. The pregnancy diagnostic was done 30 days after IA. Statistical analysis was performed using the program SAS version 9.2 (SAS 2010). The variables were analyzed by PROC MIXED, using mixed linear model for repeated measures in time. We considered effects of group, time and group x time interaction. The data obtained were submitted to ANOVA and Duncan test, using PROC GLM. The chi-square analysis was used to determine pregnancy rate, according to the quality of semen by PROC FREQ. the significance level was 5%. In experiment 1 there were no differences of the parameters evaluated by Doppler ultrasound between GIA and GC, but time effects were noted for RI, it was lower four hours after IA. When the data were evaluated according to the side of the dominant follicle was observed that 4 and 24 hours after IA, RI of AC of GIA was lower when it was compared with GC. In experiment 2 there was no difference between animals inseminated with semen B, M or R about uterine hemodynamics, but there were effects of time, so that 4 hours after IA showed lower value of RI and increased blood flow. The pregnancy rate of animals inseminated with semen B (64.7%) was higher when compared with semen R (36.2%), both of them did not differ of semen M (50.0%). It can be concluded that is not possible to detect uterine hemodynamic changes by Doppler ultrasound due to IA in cattle. The deposition of semen with different qualities does not change the uterine hemodynamics enough to be detectable by Doppler ultrasonography in cattle. On the other hand, is possible to detect changes in blood perfusion of the uterus in relation to the time of IA by Doppler ultrasound, which may be due to hormonal changes that occur during the estrous cycle. Finally, IA with semen containing a lower percentage of PIAIC sperm causes a reduction in fertility rate in cattle.
73

ASSESSMENT OF BOVINE VASCULAR SEROTONIN RECEPTOR POPULATIONS AND TRANSPORT OF ERGOT ALKALOIDS IN THE SMALL INTESTINE

Snider, Miriam A. 01 January 2017 (has links)
Prior work using a contractility bioassay determined that the serotonin (5-HT) receptor subtype 5-HT2A is present in bovine lateral saphenous veins and plays a role in ergot alkaloid-induced vascular contraction in steers grazing endophyte-infected (Epichloë coenophiala) tall fescue (Lolium arundinaceum). A study was conducted to determine what 5-HT receptors are involved in vasoconstriction of bovine gut vasculature. The findings of this study indicate that 5-HT2A is present and may play a role in ergot alkaloid induced vasoconstriction. A second study was conducted to determine if ergot alkaloids were transported in the small intestine. The active transporter, peptide transporter 1 (PepT1), was evaluated for its role in the transport of various concentrations of ergot alkaloids across Caco-2 cell monolayers. Results indicate that CEPH, ERT, EXT, and LSA do move across Caco-2 cell monolayers, but appear to utilize PepT1 at larger concentrations. Overall, the demonstrated presence of 5-HT2A receptors in the bovine gut vasculature established a potential for vascular interference by ergot alkaloids entering the bloodstream through transepithelial absorption.
74

Steath and pH-sensitive lipid nanocapsules : targeting the tumor microenvironment of melanoma / Nanocapsules lipidiques furtives et pH sensible : cibler le microenvironnement tumoral du mélanome

Pautu, Vincent 14 December 2018 (has links)
Il a été démontré que l’acidité de l’environnement tumoral jouait un rôle dans la résistance aux chimiothérapies. L’utilisation de nanovecteurs, tels que les nanocapsules lipidiques (LNC), permet non seulement d’améliorer le temps de biodistribution de substances actives, mais aussi de cibler l’environnement tumoral tout en protégeant les actifs de cet environnement acide. L’objectif de cette thèse porte ainsi sur l’optimisation et l’évaluation de LNC furtives et pH-sensibles dans le contexte du mélanome.Dans un premier temps, ces travaux ont consisté à caractériser la vascularisation de mélanomes humain et murin. Ces études ont permis de comparer différentes tumeurs (densité, taille et structure) et de déterminer si l’usage de nanomédecines est approprié dans ce contexte.La seconde partie s’est orientée sur l’élaboration de polymères combinant furtivité et pH-sensibilité. Ces copolymères composés de N-vinylpyrrolidone (NVP)et de vinylimidazole ont été synthétisés par polymérisation RAFT et post-insérés à la surface des LNC. Ces modifications ont donné lieu à des LNC présentant des charges de surface pH-dépendantes,entrainant une augmentation de leur internalisation à pH acide dans des cellules de mélanome. Finalement, des études de biodistribution ont mis en évidence l’intérêt de la NVP dans le développement de nanovecteurs furtifs. En conclusion, les copolymères développés ont permis de prolonger le temps de circulation, mais aussi d’apporter des propriétés pH-sensibles qui pourraient améliorer l’internalisation tumorale des LNC in vivo et donc de potentialiser l’effet d’une thérapie anticancéreuse. / Tumor acidity has been shown to play a major role in resistance to chemotherapy. The use of nanomedicines, as lipid nanocapsules (LNC), allows to protect drugs from this acidic environment. They can also improve the biodistribution of therapeutics and to target the tumor environment. The aim of this thesis concerns the evaluation and characterization of stealth and pH-sensitive LNC in the context of melanoma. Firstly, these works consisted in characterizing the vascularization of human and mice melanoma. These studies allowed to compare different tumors (density, size and structure), and determine if the used of nanocarrier is suitable in the context of melanoma.The second part of this thesis described the development and the characterization of new copolymers, combining stealth and pH-sensitive properties. These copolymers, composed of Nvinylpyrrolidone(NVP) and vinylimidazole, were synthesized by RAFT polymerization and were post in sertedonto LNC surface. These modifications allowed to obtain charge reversal nanocarriers, leading to increase their melanoma cell uptake underacid pH. Finally, biodistribution of these modified nanoparticles was studied in vivo and highlighted the interest of NVP in the development of stealth nanocarriers. To conclude, the developed copolymers able to extend nanocarrier circulation time and to provide pH-responsive properties which should increase the tumor internalization of LNC invivo and potentiate the effect of anticancer drugs.
75

Development of the Fetoplacental Vascular Tree in Mice During Normal and Growth Restricted Pregnancies

Rennie, Monique Yvonne 11 January 2012 (has links)
The geometry of an organ’s vascular system determines the blood flow distribution to tissues for exchange of gas and nutrients by determining its vascular resistance. The importance of vascular geometry is evident in the placenta, where insufficient fetoplacental vascularity elevates vascular resistance thereby impairing perfusion, leading to one of the most common and severe pregnancy complications, intrauterine growth restriction (IUGR). The mouse is becoming a widely used model for human placental development due to the increasing availability of mouse models thought to have a placental defect. Vascular geometry can now be imaged and quantified using micro-computed tomography (micro-CT) and results used to estimate resistance to blood flow. This thesis first describes the implementation of contrast agent perfusion and micro-CT imaging of the mouse fetoplacental vasculature throughout late gestation. Application of a vascular segmentation technique is then described and evaluated for quantification of the arterial fetoplacental tree. Normal fetoplacental vascular development in late gestation is described for two common mouse strains, CD1 and C57Bl6 (B6). In B6 placentas, both late gestational capillary growth and thinning of the interhaemal membrane were blunted relative to CD1. Analysis of CD1 and B6 tree geometry revealed a constant number of arterial segments throughout late gestation in both strains but expansion of arterial diameters in B6 only, resulting in decreased B6 arterial resistance and shear stress in late gestation. Strain dependence shows the importance of genetics in fetoplacental vascular development. Quantification of the arterial tree in a mouse model of maternal pre-pregnancy exposure to chemicals commonly found in cigarettes revealed an increase in vascular tortuousity and a reduced number of arteriole sized vessels. This led to an increase in vascular resistance and a predicted decrease in blood flow, which could contribute to the observed reduction in fetal weights. In future studies, the methods described herein can be used in phenotyping numerous mouse models which currently are suspected to have a placental vascular defect.
76

Development of the Fetoplacental Vascular Tree in Mice During Normal and Growth Restricted Pregnancies

Rennie, Monique Yvonne 11 January 2012 (has links)
The geometry of an organ’s vascular system determines the blood flow distribution to tissues for exchange of gas and nutrients by determining its vascular resistance. The importance of vascular geometry is evident in the placenta, where insufficient fetoplacental vascularity elevates vascular resistance thereby impairing perfusion, leading to one of the most common and severe pregnancy complications, intrauterine growth restriction (IUGR). The mouse is becoming a widely used model for human placental development due to the increasing availability of mouse models thought to have a placental defect. Vascular geometry can now be imaged and quantified using micro-computed tomography (micro-CT) and results used to estimate resistance to blood flow. This thesis first describes the implementation of contrast agent perfusion and micro-CT imaging of the mouse fetoplacental vasculature throughout late gestation. Application of a vascular segmentation technique is then described and evaluated for quantification of the arterial fetoplacental tree. Normal fetoplacental vascular development in late gestation is described for two common mouse strains, CD1 and C57Bl6 (B6). In B6 placentas, both late gestational capillary growth and thinning of the interhaemal membrane were blunted relative to CD1. Analysis of CD1 and B6 tree geometry revealed a constant number of arterial segments throughout late gestation in both strains but expansion of arterial diameters in B6 only, resulting in decreased B6 arterial resistance and shear stress in late gestation. Strain dependence shows the importance of genetics in fetoplacental vascular development. Quantification of the arterial tree in a mouse model of maternal pre-pregnancy exposure to chemicals commonly found in cigarettes revealed an increase in vascular tortuousity and a reduced number of arteriole sized vessels. This led to an increase in vascular resistance and a predicted decrease in blood flow, which could contribute to the observed reduction in fetal weights. In future studies, the methods described herein can be used in phenotyping numerous mouse models which currently are suspected to have a placental vascular defect.
77

Modeling of the arterial system with an AVD implanted / Modellering av det arteriella systemet med en inopererad AVD

Nyblom, Henrik January 2004 (has links)
The number of patients that are waiting for heart transplants far exceed the number of available donor hearts. Left Ventricular Assist Devices are mechanical alternatives that can help and are helping several patients. They work by taking blood from the left ventricle and ejecting that blood into the aorta. In the University of Louisville they are developing a similar device that will take the blood from the aorta instead of the ventricle. This new device is called an Artificial Vasculature Device. In this thesis the arterial system and AVD are modeled and a simple control algorithm for the AVD proposed. The arteries are modeled as a tube with linear resistance and inertia followed by a chamber with linear compliance and last a tube with linear resistance. The model is identical to the 4-element Windkessel model. The values for the resistances, inertia and compliance are identified using pressure and flow measurements from the ventricle and aortic root from a healthy patient. In addition to the Windkessel model the aortic valve is also modeled. The valve is modeled as a drum that closes the aorta and the parameters identified like before. The measurements are also used to model the left ventricle by assuming it has a constant compliance profile. The AVD is modeled using common modeling structures for servo motors and simple structures for tubes and pistons. The values for the AVD could not be measured and identified so they are fetched from preliminary motor and part specifications. The control algorithm for the AVD uses a wanted load to create a reference aortic flow. This wanted aortic flow is then achieved by using a PI controller. With these models and controller the interaction between the arterial system and AVD is investigated. With this preliminary understanding of the interaction further research can be made in the future to improve the understanding and improve the AVD itself.
78

Modeling of the arterial system with an AVD implanted / Modellering av det arteriella systemet med en inopererad AVD

Nyblom, Henrik January 2004 (has links)
<p>The number of patients that are waiting for heart transplants far exceed the number of available donor hearts. Left Ventricular Assist Devices are mechanical alternatives that can help and are helping several patients. They work by taking blood from the left ventricle and ejecting that blood into the aorta. In the University of Louisville they are developing a similar device that will take the blood from the aorta instead of the ventricle. This new device is called an Artificial Vasculature Device. In this thesis the arterial system and AVD are modeled and a simple control algorithm for the AVD proposed. </p><p>The arteries are modeled as a tube with linear resistance and inertia followed by a chamber with linear compliance and last a tube with linear resistance. The model is identical to the 4-element Windkessel model. The values for the resistances, inertia and compliance are identified using pressure and flow measurements from the ventricle and aortic root from a healthy patient. In addition to the Windkessel model the aortic valve is also modeled. The valve is modeled as a drum that closes the aorta and the parameters identified like before. The measurements are also used to model the left ventricle by assuming it has a constant compliance profile. </p><p>The AVD is modeled using common modeling structures for servo motors and simple structures for tubes and pistons. The values for the AVD could not be measured and identified so they are fetched from preliminary motor and part specifications. </p><p>The control algorithm for the AVD uses a wanted load to create a reference aortic flow. This wanted aortic flow is then achieved by using a PI controller. With these models and controller the interaction between the arterial system and AVD is investigated. </p><p>With this preliminary understanding of the interaction further research can be made in the future to improve the understanding and improve the AVD itself.</p>
79

Identifikace osob pomocí biometrie sítnice / Identification of persons using retinal biometry

Klimešová, Lenka January 2018 (has links)
This paper deals with identification of persons using retinal biometry. The retinal vasculature is invariant and unique to everyone, which determines it for biometric purposes. The first part of the work includes information about biometrics, biometric systems and reliability measures. The next part describes the principle of using experimental video ophthalmoscope, which was used for retinal vascular imaging and includes the literature research of use of retinal images for biometrics, feature extraction methods and similarity measures. Finally, two algorithms to use the input data are proposed and realized in programming environment MATLAB®. The methods are tested and evaluated on a data set from experimental video ophthalmoscope and on publicly available STRaDe and DRIVE databases.
80

Autoradiographic Localization of NK<sub>1</sub> and NK<sub>3</sub> Tachykinin Receptors in Rat Kidney

Chen, Yuejin, Hoover, Donald B. 01 January 1995 (has links)
The distribution of neurokinin receptors in rat kidney, renal artery, renal vein, and proximal ureter was evaluated by autoradiography after in vitro labeling of NK1 sites with [125I]Bolton-Hunter substance P (BHSP) or NK3 sites with [125I][MePhe7]neurokinin B ([MePhe7NKB). Film autoradiography using [125I][MePhe7]NKB revealed specific binding sites associated with the renal vein and its large branches, the renal pelvis, the inner strip of outer renal medulla, and the proximal ureter. High-resolution autoradiograms demonstrated that these sites were localized to the smooth muscle layer in the veins, pelvis, and ureter. Neither the renal arterial system nor the renal cortex contained specific [125I][MePhe7]NKB binding sites although a high level of nonspecific binding was associated with the renal artery. Specific binding of [125I]BHSP was associated with the renal artery and renal pelvis but not the renal veins. Arterial NK1 receptors appeared to be localized to the adventitia. The results indicate that at least two types of tachykinin receptor are present in the rat kidney. The distinct localization observed for most of the NK1 and NK3 receptors suggests that they have different functions.

Page generated in 0.0621 seconds