• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 17
  • 5
  • 2
  • 1
  • Tagged with
  • 34
  • 34
  • 34
  • 6
  • 6
  • 6
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 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

Molecular genetics of blood coagulation factor X

Fung, Marion R. January 1988 (has links)
Thirty thousand colonies of a bovine liver cDNA library were screened with a mixture of synthetic oligodeoxyribonucleotides coding for bovine factor X. Five positive colonies were identified, and plasmid DNA was isolated. Cleavage with restriction endonucleases showed that these plasmids (designated pBXl-5) contained inserts of 1530 bp, 770 bp, 700 bp, 1100 bp and 930 bp. DNA sequence analysis of the plasmid with the largest insert (pBXl) confirmed that bovine factor X cDNAs had been cloned. The cDNA sequence predicts that factor X is synthesized as a single chain precursor in which the light and heavy chains of plasma factor X are linked by the dipeptide Arg-Arg. The cDNA sequence also predicts that factor X is synthesized with a preproleader peptide. It is proposed that at least five specific proteolytic events occur during the conversion of preprofactor X to plasma factor Xa. A human liver cDNA library was screened by colony hybridization with a bovine factor X cDNA probe. Three of the positive plasmids contained overlapping DNA that coded for most of human factor X mRNA. A second human liver cDNA library was screened by in situ hybridization with 32P-labeled human factor X cDNA clones obtained from the first screen. Several clones were isolated that contained longer inserts. DNA sequence analysis of these clones allowed the prediction of the amino acid sequence of the precursor form of human plasma factor X. From these studies, it is predicted that human factor X is synthesized as a single polypeptide chain precursor in which the light and heavy chains of plasma factor X are linked by the tripeptide Arg-Lys-Arg. The cDNA sequence also predicts that human factor X is synthesized as a preproprotein having an aminoterminal leader peptide of 40 amino acid residues. A comparison of the amino acid sequences of human and bovine factor X shows high sequence identity around the calcium- binding regions and catalytic regions but low sequence identity around the nonfunctional regions. A human genomic phage library was screened with a human factor X cDNA as a hybridization probe. Thirty-two overlapping phage clones were isolated. Characterization of six of these clones indicates that over 32 Kbp of contiguous sequence is represented. DNA sequence and restriction map analysis shows that the factor X gene is comprised of at least 8 exons and 7 introns. No clones representing the 5' untranslated region and the prepeptide of the leader sequence were identified. Two further genomic phage libraries and two libraries specific for the 5' region of the factor X gene were screened, but no 5' end clones were obtained. Restriction enzyme mapping and Southern blot analysis indicate that thus far, the human factor X gene maps to 24 Kbp of the human genome. Comparison of the factor X gene with other vitamin K-dependent blood coagulation factor genes reveals homologous exon organization. Within the blood coagulation serine proteases factor X, factor IX, factor VII, and protein C form a closely related gene family. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate
22

Novas estratégias de purificação dos fatores de coagulação Fator VIII e Proteína C a partir de plasma humano empregando cromatografia líquida. / New strategies of purification of coagulation Factor VIII and Protein C from human plasma using liquid chromatography.

Iwashita, Claudia 19 March 2012 (has links)
Neste trabalho estudou-se a purificação de fator VIII de coagulação (FVIII) e da Proteína C (PC) por cromatografia. Em coluna ANX Sepharose FF como primeira etapa de purificação do plasma permite a eluição do FVIII e da PC com bom fator de purificação, mas não a separação destas. Propomos a separação de FVIII e PC empregando cromatografia de afinidade a metal (IMAC) empregando Cu2+, Ni2+, Zn2+, Co2+ e Fe3+ e dessorção empregando imidazol, cloreto de amônio e variação de pH. Em colunas de Fe3+ e Ni2+ as proteínas praticamente não se ligaram à resina. Em IMAC-Co2+, a PC não é adsorvida pela resina enquanto o FVIII pode ser eluído com imidazol 100 mM. Em IMAC-Cu2+ a PC eluiu com imidazol 10mM e o FVIII com 200mM. Não foi possível eluir as proteínas nem com NH4Cl 1M nem quando o pH foi abaixado até 4,0. Em IMAC-Zn2+ a PC não é adsorvida e o FVIII eluiu com imidazol 200mM ou NH4Cl 1M. Diminuindo-se o pH, a recuperação da atividade do FVIII foi baixa. Concluímos que IMAC-Co2+ apresentou os melhores rendimentos e melhores fatores de purificação para as 2 protéinas. / In this work purification methods for the coagulation factor VIII (FVIII) and Protein C (PC) by chromatography was studied. The use of ANX Sepharose FF column as the first purification step allows the elution of FVIII and PC with good purification factors, but not its separation. We propose the separation of FVIII and PC using immobilized metal ion affinity chromatography (IMAC) using Cu2+, Ni2+, Zn2+, Co2+ and Fe3+ and desorption employing imidazole, ammonium chloride and pH variation. In the columns containing Fe3+ and Ni2+ metal ions, proteins did not adsorb to the resin. In IMAC-Co2+, PC was not adsorbed to the resin, while FVIII could be eluted with 100 mM imidazole. In IMAC-Cu2+ PC could be eluted with 10 mM imidazole and FVIII with 200 mM. It was not possible to elute the proteins from IMAC-Cu2+ column with either 1M NH4Cl or when pH was descreased to 4,0. In IMAC-Zn2+, PC was not adsorbed and FVIII could be eluted with 200 mM imidazole or 1 M NH4Cl. We conclude that IMAC-Co2+ presented the best yield and purification factors for the 2 proteins.
23

Biologically active assemblies that attenuate thrombosis on blood-contacting surfaces

Qu, Zheng 12 November 2012 (has links)
All artificial organ systems and medical devices that operate in direct contact with blood elicit activation of coagulation and platelets, and their long-term use often necessitates antithrombotic therapies that carry significant cost and bleeding risk. Thrombomodulin (TM) is a major endogenous inhibitor of blood coagulation localized on the endothelial cell surface. The overall objective of this research is to develop clinically durable synthetic materials by incorporating TM as a solid-supported film to actively and sustainably attenuate thrombus formation at the blood-contacting interface. During the course of this research, we developed site-specific approaches to covalently attach TM on the luminal surface of commercial vascular grafts using bioorthogonal chemistry that was compatible with ethylene oxide sterilization. Notably, we demonstrated the superior efficacy of TM to reduce platelet deposition compared with commercial heparin modified grafts using a non-human primate model of acute graft thrombosis. Finally, we optimized a novel reversible chemistry to rapidly and repeatedly regenerate immobilized TM, with the potential to significantly extend the lifetime of biologically active films.
24

Family history in relation to myocardial infarction, and analyses of gene-environment interactions involving factors of haemostasis /

Leander, Karin, January 2005 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 4 uppsatser.
25

Haemostatic changes in plasma for transfusion during preparation and storage /

Suontaka, Anna-Maija, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.
26

Glucocorticoid regulated transcription of the [gamma] fibrinogen subunit gene in xenopus laevis

Woodward, Robert Norman, January 1996 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves : 138-152). Also available on the Internet.
27

Effect of adhesion proteins and surface chemistry on the procoagulant state of adherent platelets /

Grunkemeier, John M., January 1999 (has links)
Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 285-296).
28

Padronização das plaquetas preparadas in house para atividade do cofator da ristocetina

Utsunomia, Evandro Katsui [UNESP] 25 February 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-25Bitstream added on 2014-06-13T18:50:22Z : No. of bitstreams: 1 utsunomia_ek_me_botfm.pdf: 415505 bytes, checksum: 904bb5b0f94628384d4ffd205f0db712 (MD5) / A doença de von Willebrand (DvW) é decorrente da deficiência qualitativa ou quantitativa do Fator de von Willebrand (FvW) e é considerada a coagulopatia hereditária mais comum na população com uma prevalência de 1,1% na população geral. Para o seu diagnóstico são utilizados diversos métodos como o teste do cofator da ristocetina, que é amplamente utilizado na rotina laboratorial por ser considerado padrão-ouro na avaliação da função do fator de von Willebrand e por estar diminuído em todos os casos da doença. O kit comercial de plaquetas liofilizadas é importado, de elevado custo e possui uma validade de 30 dias após sua reconstituição se conservado de 2C a 8C. Devido à baixa prevalência da DvW na população, muitas vezes não há uma grande quantidade de exames a serem realizados, fazendo com que os plasmas desses pacientes sejam congelados e armazenados até o momento onde apareça um número mínimo de pacientes. O estudo teve como objetivo padronizar uma técnica como alternativa na utilização de plaquetas fixadas em formalina e o seu teste em indivíduos saudáveis e com a suspeita da doença, onde foram avaliados a porcentagem de atividade expressa considerando o montante de aglutinação induzida pela ristocetina, que se relaciona proporcionalmente com a concentração do FvW e o percentual de atividade normal medido através do agregômetro. O estudo possui um caráter preliminar e apresentou-se viável à rotina laboratorial, e se faz necessário não só a coleta de um número amostral maior, mas também da análise de diversas variáveis (grupo sanguíneo, idade, hormônios, estresse, uso de medicamentos) para se estabelecer nessa população um valor de referência para essa técnica / The von Willebrand disease (VWD) is caused by a qualitative or quantitative deficiency of von Willebrand Factor (vWF) and is considered the most common hereditary bleeding disorder in the population with a prevalence of 1.1% in the general population. For its diagnosis, several methods are used to test the ristocetin cofactor, which is widely used in laboratories because it is considered the gold standard in assessing the function of von Willebrand factor and to be decreased in all cases of the disease. The imported commercial kit of lyophilized platelets is costly and expires 30 days after reconstitution if stored from 2C to 8C. Due to the low prevalence of v WD in the population, usually there are not enough tests to be done, making it necessary to freeze and store the plasma of these patients until there is a minimum number of patients for testing. This study aimed to standardize a technique as an alternative to the use of formalin-fixed platelets and to test it in healthy subjects with suspected disease. Thus, the percentage of expressed activity was evaluated considering the amount of agglutination induced by ristocetin proportionally related to the concentration of vWF and the percentage of normal activity measured by an aggregometer. The study has a preliminary character and showed to be feasible for laboratory routine, and it is necessary not only to collect a larger sample size, but also to analyze several variables (blood group, age, hormones, stress, use of drugs) to establish a reference value for this technique in the population
29

Padronização das plaquetas preparadas in house para atividade do cofator da ristocetina /

Utsunomia, Evandro Katsui. January 2013 (has links)
Orientador: Izolete Aparecida Thomazini Santos / Banca: Regina K. Takahira / Banca: Michele Janegitz Acorse Valerio / Resumo: A doença de von Willebrand (DvW) é decorrente da deficiência qualitativa ou quantitativa do Fator de von Willebrand (FvW) e é considerada a coagulopatia hereditária mais comum na população com uma prevalência de 1,1% na população geral. Para o seu diagnóstico são utilizados diversos métodos como o teste do cofator da ristocetina, que é amplamente utilizado na rotina laboratorial por ser considerado padrão-ouro na avaliação da função do fator de von Willebrand e por estar diminuído em todos os casos da doença. O kit comercial de plaquetas liofilizadas é importado, de elevado custo e possui uma validade de 30 dias após sua reconstituição se conservado de 2C a 8C. Devido à baixa prevalência da DvW na população, muitas vezes não há uma grande quantidade de exames a serem realizados, fazendo com que os plasmas desses pacientes sejam congelados e armazenados até o momento onde apareça um número mínimo de pacientes. O estudo teve como objetivo padronizar uma técnica como alternativa na utilização de plaquetas fixadas em formalina e o seu teste em indivíduos saudáveis e com a suspeita da doença, onde foram avaliados a porcentagem de atividade expressa considerando o montante de aglutinação induzida pela ristocetina, que se relaciona proporcionalmente com a concentração do FvW e o percentual de atividade normal medido através do agregômetro. O estudo possui um caráter preliminar e apresentou-se viável à rotina laboratorial, e se faz necessário não só a coleta de um número amostral maior, mas também da análise de diversas variáveis (grupo sanguíneo, idade, hormônios, estresse, uso de medicamentos) para se estabelecer nessa população um valor de referência para essa técnica / Abstract: The von Willebrand disease (VWD) is caused by a qualitative or quantitative deficiency of von Willebrand Factor (vWF) and is considered the most common hereditary bleeding disorder in the population with a prevalence of 1.1% in the general population. For its diagnosis, several methods are used to test the ristocetin cofactor, which is widely used in laboratories because it is considered the gold standard in assessing the function of von Willebrand factor and to be decreased in all cases of the disease. The imported commercial kit of lyophilized platelets is costly and expires 30 days after reconstitution if stored from 2C to 8C. Due to the low prevalence of v WD in the population, usually there are not enough tests to be done, making it necessary to freeze and store the plasma of these patients until there is a minimum number of patients for testing. This study aimed to standardize a technique as an alternative to the use of formalin-fixed platelets and to test it in healthy subjects with suspected disease. Thus, the percentage of expressed activity was evaluated considering the amount of agglutination induced by ristocetin proportionally related to the concentration of vWF and the percentage of normal activity measured by an aggregometer. The study has a preliminary character and showed to be feasible for laboratory routine, and it is necessary not only to collect a larger sample size, but also to analyze several variables (blood group, age, hormones, stress, use of drugs) to establish a reference value for this technique in the population / Mestre
30

Pentasaccharides para o tratamento da trombose venosa profunda

Brandão, Gustavo Muçouçah Sampaio. January 2016 (has links)
Orientador: Hamilton Almeida Rollo / Coorientador: Marcone Lima Sobreira / Resumo: Pentasaccharides para o tratamento da trombose venosa profunda Questão da revisão: Os novos anticoagulantes da classe dos pentasaccharides podem ser uma alternativa eficaz e segura aos anticoagulantes convencionais utilizados na terapia padrão do tratamento da trombose venosa profunda? Visão geral: Trombose venosa profunda (TVP) é uma doença grave e potencialmente fatal que se caracteriza pela formação aguda de um coágulo de sangue nas veias profundas. Sua incidência aumenta exponencialmente com a idade e estima-se que na população geral, sua incidência seja de 5 casos em 10,000 habitantes. O tratamento padrão se faz por meio de medicamentos anticoagulantes, inicialmente pela administração de medicamentos injetáveis, as heparinas, por 5 a 7 dias e em seguida pelo uso prolongado de medicamentos de uso oral, os antagonistas da vitamina K. Entretanto, o alto risco de sangramento e a necessidade de um rigoroso controle laboratorial, permanecem como importantes limitações à terapia padrão. Os pentasaccharides são anticoagulantes sintéticos que podem apresentar vantagens em relação ao tratamento convencional como um efeito mais previsível, um regime de dosagem mais conveniente, a ausência da necessidade de controle laboratorial, ausência de interações com medicamentos e/ou alimentos, ausência da temida diminuição das plaquetas induzida pela heparina e em muitos casos melhor custo-benefício. Características chaves e resultados: Nossas buscas, realizadas até julho de 2015, iden... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: Deep vein thrombosis (DVT) is a severe disorder caused by acute formation of a clot or thrombus in the deep vein system. The incidence of DVT increases with age: from 2 to 3/10,000 in adults aged 30 to 49 years to 20/10,000 in adults aged 70 to 79 years. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Standard treatment is based on antithrombotic therapy, initially with parenteral administration of unfractionated heparin or low molecular weight heparins (LMWH) for five to seven days, then subsequent long-term oral vitamin K antagonists (e.g. warfarin) therapy. However, hemorrhagic complications are a major concern associated with warfarin treatment. Indeed, the hemorrhagic risk of warfarin and the required laboratory control remain the Achilles' heel of vitamin K antagonist management. The pentasaccharides have characteristics that may be favourable over conventional treatment, including a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions and absence of heparin-induced thrombocytopenia. To date, no systematic review has measured the effectiveness and safety of these drugs in the treatment of DVT. Objectives: To assess the efficacy and harms of pentasaccharides for the treatment of deep venous thrombosis. Search strategy: 1 The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched... (Complete abstract click electronic access below) / Doutor

Page generated in 0.1381 seconds