• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 81
  • 36
  • 5
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 153
  • 80
  • 15
  • 12
  • 11
  • 10
  • 10
  • 9
  • 9
  • 9
  • 9
  • 9
  • 9
  • 8
  • 8
  • 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.
21

Morphometrical Methodology in Quantification of Biological Tissue Components

Blomgren, Bo January 2004 (has links)
<p><b>Objective:</b></p><p>To develop and validate computer-assisted morphometrical methods, based on stereological theory, in order to facilitate the analysis and quantitative measurements of biological tissue components.</p><p><b>Material and methods:</b></p><p>Biopsy specimens from the vaginal wall or from the vestibulum vaginae of healthy women, or from women suffering from incontinence or vestibulitis were used.</p><p>A number of histochemical methods for light microscopy were used, and modified for the different morphometrical analyses. Electron microscopy was used to reveal collagen fibre diameter.</p><p>Computer-assisted morphometry, based on image analysis and stereology, was employed to analyse the different tissue components in the biopsies. Computer programs for these purposes were developed and validated.</p><p><b>Results:</b></p><p>The results show that computer-assisted morphometry is of great value for quantitative measurements of the following tissue components:</p><p><b>Epithelium:</b> The epithelial structure, instead of just thickness, was measured in an unbiased way.</p><p><b>Collagen:</b> The collagen fibril diameter was determined in electron microscopic specimens, and the collagen content was analysed in light microscopic specimens.</p><p><b>Elastic fibres:</b> The amount of elastic fibres in the connective tissue was measured after visualisation by autofluorescence.</p><p><b>Vasculature:</b> A stereological method using a cycloid grid was implemented in a computer program. Healthy subjects were compared with patients suffering from vestibulitis. The results were identical in the two groups.</p><p><b>Smooth muscle:</b> A stereological method using a point grid was implemented in a computer program. Using the Delesse principle, the fibres were calculated as area fractions. The area fractions were highly variable among the different specimens.</p><p><b>Conclusion:</b></p><p>Morphometry, used correctly, is an important analysis method in histopathological research. It is important that the methods are as simple and user-friendly as possible. The present studies show that this methodology can be applied for most quantitative histological analyses.</p>
22

Morphometrical Methodology in Quantification of Biological Tissue Components

Blomgren, Bo January 2004 (has links)
<b>Objective:</b> To develop and validate computer-assisted morphometrical methods, based on stereological theory, in order to facilitate the analysis and quantitative measurements of biological tissue components. <b>Material and methods:</b> Biopsy specimens from the vaginal wall or from the vestibulum vaginae of healthy women, or from women suffering from incontinence or vestibulitis were used. A number of histochemical methods for light microscopy were used, and modified for the different morphometrical analyses. Electron microscopy was used to reveal collagen fibre diameter. Computer-assisted morphometry, based on image analysis and stereology, was employed to analyse the different tissue components in the biopsies. Computer programs for these purposes were developed and validated. <b>Results:</b> The results show that computer-assisted morphometry is of great value for quantitative measurements of the following tissue components: <b>Epithelium:</b> The epithelial structure, instead of just thickness, was measured in an unbiased way. <b>Collagen:</b> The collagen fibril diameter was determined in electron microscopic specimens, and the collagen content was analysed in light microscopic specimens. <b>Elastic fibres:</b> The amount of elastic fibres in the connective tissue was measured after visualisation by autofluorescence. <b>Vasculature:</b> A stereological method using a cycloid grid was implemented in a computer program. Healthy subjects were compared with patients suffering from vestibulitis. The results were identical in the two groups. <b>Smooth muscle:</b> A stereological method using a point grid was implemented in a computer program. Using the Delesse principle, the fibres were calculated as area fractions. The area fractions were highly variable among the different specimens. <b>Conclusion:</b> Morphometry, used correctly, is an important analysis method in histopathological research. It is important that the methods are as simple and user-friendly as possible. The present studies show that this methodology can be applied for most quantitative histological analyses.
23

Development of digital image analysis and stereological techniques to incorporate microstructural information in finite element based simulations

Yang, Shichen 05 1900 (has links)
No description available.
24

The textural effects of multiphase mineral systems in liberation measurement

Latti, Anna Dewetia. Unknown Date (has links)
No description available.
25

The textural effects of multiphase mineral systems in liberation measurement /

Latti, Anna Dewetia. January 2006 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2006. / CD-ROM has title : The testural [sic] effects of multiphase mineral systemsin liberation measurement. Includes bibliography.
26

Avaliação macroscópica, microscópica e estereológica de implante de biomembrana em estômago de coelhos (Oryctolagus cuniculus)

Scavone, Alessandra Regina Freixo [UNESP] 19 February 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-19Bitstream added on 2014-06-13T19:30:11Z : No. of bitstreams: 1 scavone_arf_me_jabo.pdf: 1274995 bytes, checksum: 0e2f0c104877e36f7e533b10ff78fb89 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Neste estudo, implantou-se biomembrana de látex natural em defeito (1,5 x 1,5 cm) induzido na parede de estômago de coelhos, com o intuito de se avaliar o processo de reparação tecidual no que se refere à biocompatibilidade, capacidade de reparação e possíveis complicações. Utilizaram-se 24 coelhos, albinos, raça Nova Zelândia Branco, adultos, machos inteiros, divididos em grupos experimentais: Grupo Biomembrana Fundo (GBF), Grupo Biomembrana Corpo (GBC), Grupo Controle Fundo (GCF) e Grupo Controle Corpo (GCC). Aos quinze, 30 e 60 dias de pós-operatório, os animais foram sacrificados, para as avaliações. Macroscopicamente, aos quinze dias de pós-operatório observou-se em 100% dos animais presença de aderências na face serosa e a presença da biomembrana na face luminal. Aos 30 dias de pós-operatório 37,5% dos animais avaliados apresentaram aderências na face serosa e em 62,5% dos animais não ocorreram aderências em nenhuma estrutura. Neste mesmo período, todos os animais ainda apresentavam a biomembrana na face mucosa. Aos 60 dias de pósoperatório, 50% dos animais estudados não apresentaram aderências em nenhuma estrutura e em 50% dos animais, foi observada aderências na face serosa. Neste período, em todos os animais avaliados a biomembrana não foi encontrada. Sob microscopia de luz, no grupo Biomembrana aos quinze e 30 dias verificaram-se descontinuidade das camadas muscular e mucosa, presença de infiltrado inflamatório polimorfonuclear. Foi visualizado vasos sanguíneos e fibras musculares. Aos 60 dias as camadas mucosa, muscular estavam completamente recontituídas. No grupo GC, aos quinze e 30 dias de pós-operatório verificou-se descontinuidade da camada muscular e mucosa neoformada e presença de infiltrado inflamatório mononuclear em submucosa. Já aos 60 dias, a mucosa mostrou-se reconstituída... / In this study, biomembrane of natural latex was utilized to replace a section of face of the stomach of rabbits, with purpose of evaluation of the tissue repair process in regard of its biocompatility, scar formation ability and possible complications. Twentyfour New Zealand rabbits, adult and non-castrated males were divided in experimental groups: Biomembrane Fund Group (GBF), Biomembrane Body Group (GBC), Control Fund Group (GCF) and Control Body Group (GCC). The animals were euthanized at fifteen, 30 and 60 days of post operative, followed by analysis. Macroscopically, in fifteen days of post operative were observed in 100% of the animals presence in the serosal face, the adherences and in the luminal face the biomembrane. In 30 days of post operative 37,5% of the animals, presence in the serosal face, the adherences and 62,5% were observed in of the animals absence of the adherences. In this time, all of the animals were observed in the luminal face the biomembrane. In 60 days of post operative 50% of the animals were observed absence of the adherences, and in 50% of the animals, presence in the serosal face, the adherences. In this time the biomembrana is not in the stomach. Under light microscopy, in the Biomembrane group at fifteen and 30 days, were observed discontinuity of muscle layer and mucosa layer, presence of polimorfonuclear population of inflammatory cells. New vessels and muscle fibers were observed. In 60 days the mucosa, muscle layers were complete reconstituted. In the GP group, at 15 and 30 days of post operative were observed discontinuity of muscle layer and mucosa formed and presence of mononuclear population of inflammatory cells in submucosa. In 60 days, hypoglandular and complete layer reconstituted mucosa and muscle layers were complete reconstituted. The stereologic... (Complete abstract click electronic access below)
27

Avaliação estereológica da microestrutura do fígado em animais desnutridos e submetidos à renutrição protéica / Stereological evaluation of microstructure in the liver of animals denutrition of followed by proteic renutrition

Silvio Pires Gomes 24 March 2011 (has links)
A fome e a má nutrição permanecem entre os problemas mais devastadores que enfrentam a maioria dos pobres e carentes do mundo. A desnutrição está relacionada com o desequilíbrio do estado nutricional e ocorre sob diversas formas, podendo afetar o fígado. A desnutrição no início da vida pode afetar profundamente o corpo e o cérebro de ratos adultos. Alguns desses efeitos são permanentes enquanto outros desaparecem quando os animais são submetidos ao processo de renutrição. Sendo assim, outra maneira de interferir na regeneração hepática fundamenta-se no fato de que os processos proliferativos do fígado podem ser modulados por fatores alimentares. Experimentos de desnutrição protéico-energética mostraram que o fígado de ratos desnutridos regenera-se mais lentamente após a hepatectomia. O objetivo deste estudo foi avaliar os efeitos da desnutrição e renutrição protéica na microestrutura dos fígados de camundongos. Foram utilizados 12 camundongos Swiss machos, subdividos nos seguintes grupos: Controle do desnutrido (CD) (n=3), Desnutrido (D) (n=3), Renutrido (R) (n=3) e Controle do renutrido (CR) (n=3). Os animais dos dois grupos controle e do grupo renutrido receberam ração normoprotéica (12%) ao passo que o grupo desnutrido recebeu ração hipoprotéica contendo (2%). Os seguintes parâmetros estereológicos do fígado foram estimados: volume, número total e o volume menor (p= 0,001) em relação ao CR (R= 8020 µm³ e CR= 10018 µm³). O número total de hepatócitos nos animais desnutridos não apresentou diferença significativa (p= 0,055) em comparação ao seu CR (D = 1.1 x 107 e CD=1.6 x 107) e o R não apresentou diferença significativa (p= 0,055) em comparação ao seu CR (R= 2.8 x 107 e CR= 2.2 x 107). Portanto, a renutrição atenuou a atrofia do volume do hepatócito ocasionada pelo processo de desnutrição (carência de proteína). / The hunger and the malnutrition remain the most devastating problems faced by the majority of poor and needy people in the world. The malnutrition is related to an unbalanced nutritional condition and it occurs in different ways may affecting the liver. In the beginning of life, the malnutrition can affect profoundly the body and the brain in adult rats. Most of these effects are permanent while others disappear when the animal are submitted to a renutrition process. In this way, other manner to interfere in the hepatic regeneration is based on the fact that the liver proliferative processes might be modulating by food factors. The energetic protein malnutrition experiments have showed that the undernourished rat livers regenerate slower after hepatectomy. The aim of this study was to evaluate the effects of the caloric protein malnutrition and renutrition in the liver microstructure. In this study were used 12 Swiss male mice divided in: control of the undernourished mice (UC) (n=3), undernourished (U) (n=3), renourished (RN) (n=3) and control of the renourished (RNC) (n=3). The animals from both control groups and the undernourished group received normal protein food (12% protein) and the undernourished group received hypoprotein food (2% protein). The following stereological parameters were estimated: volume, total number and mean volume of the hepatocytes. The mean volume of U was significantly lower (p=0.001) than the UC (U= 23.57 mm³ e UC= 46.5 2mm³) and RN was lower (p=0.001) than the RNC (RN= 38.89 mm³ e RNC= 52.03 mm³).The mean volume of hepatocytes in undernourished animals was lower (p=0.001) in comparison with the respective control (U= 4505 µm³ e CD= 8170.13 µm³) and the RN was lower (p= 0.001) in relation to the RNC (RN= 8020 µm³ e RNC= 10018 µm³). The total number of hepatocytes in undernourished animals did not presented significant difference (p= 0.055) in comparison with the respective control (U = 1.1 x 107 e UC= 1.6 x 107). So, the renutrition attenuated the hepatocyte volume atrophy caused by the malnutrition process (protein deficiency).
28

Stereological Analysis of Oligodendrocyte Progenitor Cells In the Adult Mouse Brain

Boulanger, Jenna January 2017 (has links)
The main goal of this study was to further explore the hypothesis that experience-dependent neural network activity and neurotransmission can modulate adult OPC proliferation and differentiation. More specifically, we used stereology to establish whether extensive reference memory training and system-wide administration of GABAergic agonists and antagonists could influence the proliferation and differentiation of adult OPCs, as well as the prevalence of OPC-neuron pairs. Analysis of the effects of reference memory training on OPC proliferation and differentiation corresponds to experiment 2, analysis of the effects of GABAergic agents on OPC proliferation and differentiation corresponds to experiment 3, and analysis of the effects of both reference memory training and GABAergic agents on OPC-neuron pairs, as well as an histological analysis of these closely apposed cells, corresponds to experiment 4.
29

Punção aspirativa percutanea do epididimo (PESA) : estudo quantitativo, histologico e estereologico em ratos / Percutaneous epididymal sperm aspiration (PESA) : quantitative, histological and stereological study in rats

Saade, Ricardo Destro 30 August 2006 (has links)
Orientadores: Carlos Arturo Levi D'Ancona, Paulo Augusto Neves / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T11:43:00Z (GMT). No. of bitstreams: 1 Saade_RicardoDestro_D.pdf: 1299944 bytes, checksum: dfdd6825fd6739a18659a773638e845d (MD5) Previous issue date: 2006 / Resumo: Introdução: O tratamento da infertilidade masculina tem evoluído muito nas últimas décadas. O advento de técnicas de reprodução assistida (RA) e, particularmente, a injeção intracitoplasmática de espermatozóides (ICSI) tornaram possível o tratamento de indivíduos até então considerados inférteis, como os casos de azoospermia obstrutiva e os de azoospermia não obstrutiva. Nestes casos, na impossibilidade de correção cirúrgica, outros procedimentos de obtenção de espermatozóides podem ser realizados como a aspiração microcirúrgica dos epidídimos (MESA), punção aspirativa percutânea dos epidídimos (PESA), aspiração testicular de espermatozóides (TESA) ou a extração testicular (TESE). Objetivos: A proposta de trabalho foi verificar a obtenção de espermatozóides viáveis em até cinco punções percutâneas do epidídimo. Analisar as alterações histológicas inflamatórias e cicatriciais, assim como a densidade de fibras de músculo liso e colágenas nos epidídimos de ratos, após punções. Material e método: O grupo piloto consistiu em quatro animais, sendo dois para estudo da anatomia e da histologia do epidídimo normal e outros dois para avaliação dos efeitos da vasectomia. A vasectomia bilateral foi realizada por meio de laparotomia infra-umbilical. Foi padronizado o lado direito para estudo e o esquerdo como controle. O grupo estudado consistiu em 50 ratos que realizaram vasectomia e foram separados em cinco grupos de I a V, contendo 10 animais cada. Os animais do grupo I foram submetidos a uma punção percutânea trans-escrotal; II a duas punções; III a três punções; IV a quatro punções; V a cinco punções. As punções dos epidídimos foram feitas após 30 dias da vasectomia, com escalpe 25G na cabeça do epidídimo. O material extraído foi suspenso em meio de cultura HTF e analisado em câmara de Makler. O intervalo entre cada punção foi de 15 dias e os animais foram sacrificados após 15 dias da última punção. Os epidídimos foram fixados em líquido de Bouin. Foram realizados estudos histológicos e estereológicos dos epidídimos puncionados. Resultados: O número médio de espermatozóides recuperados nas punções foi de: 48,78 x 106 /ml, 37,55 x 106 /ml, 26,33 x 106 /ml, 33,90 x 106 /ml e 41,34 x 106 /ml, nos grupos I a V, respectivamente. Após a análise histológica, observou-se que as variáveis infiltrado linfoplasmocitário, reação granulomatosa, fibrose e desarranjo estrutural apresentaram diferença significativa a partir da segunda punção. O efeito cumulativo das punções somente foi observado nas variáveis infiltrado linfoplasmocitário e fibrose, mostrando que existe diferença significativa entre os grupos I e II em relação aos grupos III, IV e V. No estudo estereológico, a densidade volumétrica do tecido conjuntivo foi de 21,56%, 27,60%, 35,67%, 37,56% e 38,60% no lado puncionado nos grupos I a V (p<0,05). Conclusões: No presente estudo, verificamos a obtenção de espermatozóides em todos os grupos até cinco punções. Todos os animais apresentaram alterações histológicas significativas dos epidídimos, quando comparados ao grupo controle, a partir da segunda punção, exceto na variável necrose. Somente nas variáveis infiltrado linfoplasmocitário e fibrose foram observadas efeito cumulativo das PESA. O estudo estereológico demonstrou aumento da densidade volume do tecido conjuntivo dos epidídimos provocado pelas punções / Abstract: Introduction: The treatment of male infertility had a great development in the last decades. The advent of assist reproductive techniques and specially the intra-cytoplasmic sperm injection (ICSI) has allowed the treatment of these patients otherwise considered infertile. Patients with obstructive and non-obstructive azoospermia, whose surgical reconstruction is not possible, can be submitted to retrieval spermatozoa procedures including microsurgical epididymal sperm aspiration (MESA), percutaneous epididymal sperm aspiration (PESA) testicular sperm extraction (TESE) and testicular sperm aspiration (TESA). Objectives: To verify the retrieval of viable spermatozoa within up to five percutaneous epididymal sperm aspirations and to evaluate the histological and stereological modifications in the rat epididymis after the procedures. Material and Methods: The pilot group consisted of four animals, two of them were used in the study about anatomy and histology of normal epididymis. The other two were used to verify the effects of the vasectomy. These procedures were performed through infra-umbilical laparotomy. The right side was standardized for the study group and the left for control. A total of 50 Wistar rats underwent vasectomy procedures and were distributed into five groups I to V, totalizing 10 animals each. In the group I, the animals underwent to one PESA procedure, II two, III three, IV four and V five. The epididymal punctures were done with 25G scalp in the caput after 30 days of the vasectomy and consecutively after 15 days of the previous puncture. The material extracted was suspended in HTF solution culture and analyzed in a Makler chamber. The epididymis were fixed in Bouin technique. Histological and stereological analyses were performed in the punctured epididymidis. Results: The number of retrieved spermatozoa was: mean 48.78 x 106 /ml, 37.55 x 106 /ml, 26.33 x 106 /ml, 33.90 x 106 /ml e 41.34 x 106 /ml, from group I to V. The histological analyses included evaluation of infiltration of lymphocytes and plasmocytes, granulomatous reaction, fibrosis and structural disorder; these alterations presented significant differences after the second puncture. The cumulative effect was observed only within the variables: lymphocytic and plasmocytic infiltrate and fibrosis. It was found differences in the groups I and II in comparison with III, IV and V. The stereological analyzes showed significant increase in connective tissue volume 21.56%, 27.60%, 35.67%, 37.56% and 38.60% from group I through V. Conclusions: In this study, it was performed retrieval of spermatozoa in all groups up to five punctures. All the animals presented histological alterations in the epididymis after the second puncture when compared to the control group, except necrosis, and only lymphocytic and plasmocytic infiltrate and fibrosis were shown as cumulative effects within the punctures. The stereological analyses showed increase of connective tissue volume that was caused by the punctures / Doutorado / Cirurgia / Doutor em Cirurgia
30

Auswirkungen von (-)-Δ9-trans-Tetrahydrocannabinol auf Zellzahl und adulte Neurogenese im Hippocampus / Effects of (-)-Δ9-trans-Tetrahydrocannabinol on cell number and adult neurogenesis in the hippocampus

Silcher, Barbara 09 March 2021 (has links)
No description available.

Page generated in 0.074 seconds