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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.
161

Protein Separation with Ion-exchange Membrane Chromatography

Cao, Liming 04 May 2005 (has links)
Membrane chromatography is a promising process for the isolation, purification, and recovery of proteins, enzymes, and nuclear acids. Comparing with traditional beads column chromatography, membrane chromatography can faster, easier and cheaper to mass-produce. And also, it is easy to set up and scale up. In this thesis, we are trying to study the performance of membrane chromatography, and the mixture of HSA and chicken egg white is used as an example. We are investigating the purification of Human serum albumin (HSA) from chicken egg white in terms of precondition, dilution, purification method, product recovery, product purity and product cost. HSA, is a very important clinical protein. In order to obtain low cost, high efficiency and less risk HSA, recombinant DNA technology is used. Many kinds of host organism have been used to produce recombinant HSA (rHSA). In this thesis, a kind of ion-exchange membrane (Mustang Q membrane capsule) chromatography was used. The membrane capsule is disposable because it is designed for use in pharmaceutical production. For this project, a cleaning method was used which made the membrane capsule reusable. Washing with 4 mL 1 M NaCl and 4 mL NaOH was sufficient for this purpose. Since the egg white protein solution was very viscous, it needs to be diluted before loaded on FPLC. Dilute experiment was done to find the best dilution level. In this thesis, we found that 5 times dilution was best not only for high efficiency but also for FPLC operation. After getting the basic conditions, some purification experiments were done to find the optimal operation condition to purify HSA form chicken egg white protein solution by changing buffer pH, salt concentration in elution buffer and gradient used to elute proteins. The best purification condition for loading buffer is Tris-HCl buffer A (4.75g/L, pH 9.5) and the elution buffer is Tris-HCl buffer A + 0.2M NaCl. The purity of HSA recovered was 93% on the Mustang Q membrane capsule at 1 ml/min when the mixture of HSA and chicken egg white was diluted 10 times. And the yield was 85%. The impurity is probably ovoglobulin as suggested by the result of SDS-PAGE, whose molecular weight is close to 40kd. To characterize the separation capability of the Mustang Q membrane capsules, equilibrium adsorption and breakthrough curve studies were made using bovine serum albumin (BSA). 1mg/mL BSA solution was used to get the breakthrough curve with different flow rate ranging from 1 to 4 ml/min. With a flow rate is 1 ml/min, breakthrough curve were obtained with different concentrations of BSA ranging from 1 to 16 mg/mL. The dynamic binding capacity was found to be from 9.1 to 119.1 mg/mL. The equilibrium adsorption isotherm showed Langmuir isotherm behavior with dissociation constant and a maximum adsorption capability. According to the result of isotherm adsorption, a multi-plate mathematical model was used to get the theoretical breakthrough curve. By fitting the theoretical breakthrough curve to the experimental breakthrough curve, constants in the multi-plate model were obtained and were used to estimate the axial dispersion coefficient of the membrane capsule. The estimated axial dispersion coefficient of 2.45*10-6 cm2/s is very small which means that the axial ispersion is not significant. The adsorption process is therefore controlled by radial radius dispersion or film dispersion.
162

Identification of a novel interaction partner of serine-arginine protein kinase 2 and studies on their roles in transcriptional regulation.

January 2014 (has links)
SR蛋白在前體信使核糖核酸(pre-mRNA)的組成性剪接和選擇性剪接中扮演者重要的角色,在這個過程中它需要被SR蛋白激酶(SRPK) 燐酸化才能正常行使功能。經典的SR蛋白是由N端一到二個RNA識別基序(RRM) 以及C端一串精氨酸-絲氨酸(RS) 二肽所構成。SR蛋白的燐酸化調控它的亞細胞定位以及生理功能。此外,SR 蛋白激酶1(SRPK1) 和SR蛋白原型ASF/SF2的復合物結構顯示底物的結合需要第二個非標準的RRM結構域以及在N端可以被燐酸化的RS結構域,但是,第一個標準的RRM結構域對於SR 蛋白激酶1的結合卻是可以或缺的。 / 在這裡,我們展示了SR蛋白激酶2(SRPK2) 結合並且燐酸化SRp20的RS結構域,SRp20是另外一個只包含一個RNA識別基序(RRM) 的SR蛋白。與ASF/SF2相似的是,SRp20中的標準RNA識別基序對於SRPK2的結合並不是必要的。與此同時,我們發現錨定槽對於底物的識別作用在SRPK2中也是保守的,因為,錨定槽中四個關鍵氨基酸的突變會削弱它對SRp20的結合。 / 此外,現在認為SRPK2的功能已經不限於對前體信使核糖核酸(pre-mRNA) 的剪接調控。最近發現,SRPK2也可以燐酸化Tau蛋白並且介導阿爾茨海默疾病中的認知性缺陷。組成性的激活是SR蛋白激酶中的一個固有特性,然而人們對於它的調控機制還不是很清楚。因此, 為了更好的瞭解SRPK2,我們采用酵母雙雜交的方法並且最終發現一個新的SRPK2相互作用蛋白: ZNF187。 / ZNF187是一個可以結合血清反應元件(SRE) 的轉綠因子。我們的研究發現,它可以正向調控SRE的轉錄激活。然而,SRPK2在EGF的刺激下卻起着抑制的效果,其中EGF的刺激會促使SRPK2進入細胞核。進一步證實,通過RNAi干擾的方法敲掉SRPK2可以增加ZNF187誘導的SRE活性。在共轉染實驗中,SRPK2可以把ZNF187誘導的SRE活性逆轉到本底水平。對於可以和EGF刺激的SRPK2有着相似細胞定位的缺失或者突變研究發現,它們都可以產生相一致的抑制現象。於此相反,對於和SRPK2有着不同細胞定位的突變,它卻不能產生抑制效果。因此,我們認為在EGF的刺激下,SRPK2進入細胞核並且負向的調控ZNF187激活的SRE。令人驚訝的是,如果細胞在FBS的刺激下,SRPK2卻上調SRE活性,並且它可以協同增加ZNF187對於SRE的誘導。這些結果表明SRPK2對於ZNF187誘導的SRE轉綠調控是刺激物依賴的。 / SR proteins are critical players in regulating both constitutive and alternative pre-mRNA splicing, during which the phosphorylation by SR Protein Kinases (SRPKs) is required. Classical SR proteins contain one or two RNA Recognition Motifs (RRM) in their N terminus and a stretch of Arginine-Serine (RS) dipeptides in C terminus. Phosphorylation status of SR proteins regulates their subcellular localization as well as physiological function. In addition, complex structure of SRPK1 with ASF/SF2, a prototype of SR protein, shows that substrate binding requires non-canonicalRRM2 domain and RS domain, which can be extensivelyphosphorylated. However, the canonical RRM1 domain is dispensable for such interaction. / Here we show that SRPK2 binds and phosphorylates SRp20, a classical single RRM domain-containing SR protein, at its RS domain. Similarly with ASF/SF2, the canonical RRM domain of SRp20 is dispensable for interacting with SRPK2. Meanwhile, we also find that a docking groove that iscritical for substrate binding in SRPK1 is also conserved in SRPK2, since mutations on four key residues in docking groove impair its binding affinity with SRp20. / In addition, SRPK2 is now known to function more then regulating mRNA splicing, such as cell proliferation and cell apoptosis. Recently, SRPK2 is also shown to be a kinase phosphorylating Tau and mediate the cognitive defects in Alzheimer’s disease (AD). Besides, an intrinsic character of SRPKs lies in that they are constitutively active, but the regulation mechanism is not well understood. Therefore, in order to obtain a better recognition about SRPK2, we applied yeast two-hybrid assay and eventually anew interaction partner called ZNF187 was identified. / ZNF187 is a transcriptional factor that binds with Serum Response Element (SRE). Our studies showed that it isa positive regulator of SRE activity. However, SRPK2 showed inhibiting effect on SRE activation with the treatment of EGF, which could induce its nucleus entry, when co-transfected, it reversed the stimulating effect on SRE by ZNF187 to basal level. Furthermore, knockdown of SRPK2 by RNAi would enhance ZNF187-stimuated SRE activation. Studies on truncation and mutations that have the similar effect with EGF-induced subcellular localization of SRPK2 also generated the same inhibiting phenomenon. In contrast, mutant that has distinct localization with SRPK2 wild type failed to exert suppression. Therefore, we conclude that with the treatment of EGF, SRPK2 moves into nucleus and negatively regulates ZNF187-stimulated transactivation of SRE. Surprisingly, when cells were treated with FBS, SRPK2 showed stimulation on SRE activity and it synergized ZNF187-stimulated effect on SRE, indicating that transcriptional regulation of SRPK2 on ZNF187-stimulated SRE activity is stimuli-dependent. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Shang, Yong. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 113-137). / Abstracts also in Chinese.
163

Production of antibodies for the measurement of human serum lipoproteins.

January 1997 (has links)
by Frankie Kar-Ming Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 101-107). / Acknowledgements --- p.IV / Abstract --- p.V / Abbreviations --- p.VI / Chapter Chapter 1 --- Introduction to Lipoprotein and Apolipoprotein --- p.1 / Chapter 1.1 --- Lipoprotein structure and classification --- p.1 / Chapter 1.2 --- Apolipoprotein A-I and B100 --- p.1 / Chapter 1.2.1 --- Apolipoprotein A-I (apoA-I) --- p.1 / Chapter 1.2.2 --- Apolipoprotein B100 (apoB100) --- p.3 / Chapter 1.2.3 --- Biological functions of apolipoprotein --- p.4 / Chapter 1.3 --- Evidence linking apoA-I and B100 with atherosclerosis --- p.4 / Chapter 1.4 --- The roles of apoA-I and B100 in the development of atherosclerosis --- p.6 / Chapter 1.5 --- Measurement of human serum lipoproteins as an assessment of risk for coronary heart disease (CHD) --- p.8 / Chapter 1.6 --- Aims of this study --- p.10 / Chapter Chapter 2 --- Purification of ApoA-I and B100 and Production of Polyclonal Antibodies --- p.12 / Chapter 2.1 --- Introduction --- p.12 / Chapter 2.1.1 --- Purification of apoA-I and B100 from human serum --- p.12 / Chapter 2.1.2 --- Immunization for polyclonal antibodies production against apoA-I and B100 --- p.14 / Chapter 2.1.3 --- Antibody purification --- p.15 / Chapter 2.1.3.1 --- Ammonium sulfate precipitation --- p.17 / Chapter 2.1.3.2 --- DEAE and QEAE Sepharose --- p.17 / Chapter 2.1.3.3 --- Protein A and Protein G --- p.17 / Chapter 2.1.3.4 --- Affinity chromatography --- p.18 / Chapter 2.2 --- Methods --- p.20 / Chapter 2.2.1 --- Purification of HDL and LDL --- p.20 / Chapter 2.2.2 --- Purification of apolipoproteins --- p.22 / Chapter 2.2.3 --- Immunization of rabbit with apoA-I and B100 --- p.23 / Chapter 2.2.4 --- Enzyme-linked immunosorbent assay (ELISA) --- p.24 / Chapter 2.2.5 --- Purification of lipoprotein specific immunoglobulin from antisera --- p.25 / Chapter 2.2.5.1 --- Salt fractionation --- p.25 / Chapter 2.2.5.2 --- Purification of immunoglobulin by Protein A affinity chromatography --- p.25 / Chapter 2.2.5.3 --- Isolation of specific antibody by lipoprotein-coupled affinity chromatography --- p.26 / Chapter 2.3 --- Results --- p.27 / Chapter 2.3.1 --- Purification of apoA-I and B100 --- p.27 / Chapter 2.3.2 --- Purification of immunoglobulins from rabbit anti-apolipoprotein sera --- p.32 / Chapter 2.4 --- Discussion --- p.38 / Chapter Chapter 3 --- Production of monoclonal antibodies against apoA-I and B100 --- p.48 / Chapter 3.1 --- Introduction --- p.48 / Chapter 3.1.1 --- What is monoclonal antibody? --- p.48 / Chapter 3.1.2 --- The basic methodology --- p.49 / Chapter 3.1.2.1 --- Immunization of host --- p.49 / Chapter 3.1.2.2 --- Cell lines required for fusion --- p.49 / Chapter 3.1.2.3 --- Fusion --- p.51 / Chapter 3.1.2.4 --- Selection of hybrids --- p.52 / Chapter 3.1.2.5 --- Screening assay --- p.54 / Chapter 3.1.2.6 --- Cloning --- p.54 / Chapter 3.1.2.7 --- Bulk production of monoclonal antibody --- p.55 / Chapter 3.1.2.8 --- Monoclonal antibody purification --- p.55 / Chapter 3.2 --- Methods --- p.55 / Chapter 3.2.1 --- Immunization of mice with apoA-I and apoB100 --- p.55 / Chapter 3.2.2 --- Preparation before fusion --- p.58 / Chapter 3.2.2.1 --- Preparation of tissue culture working solutions --- p.58 / Chapter 3.2.2.2 --- Preparation of spleen cells --- p.59 / Chapter 3.2.2.3 --- Preparation of myeloma cells --- p.60 / Chapter 3.2.3 --- Fusion --- p.60 / Chapter 3.2.4 --- Screening assay for positive clones --- p.61 / Chapter 3.2.5 --- Limiting dilution cloning --- p.61 / Chapter 3.2.6 --- Determination of isotype --- p.62 / Chapter 3.2.7 --- Cryopreservation of myeloma and established hybridoma cell lines --- p.62 / Chapter 3.2.7.1 --- Freezing cells --- p.62 / Chapter 3.2.7.2 --- Thawing cells --- p.63 / Chapter 3.2.8 --- Bulk production of monoclonal antibodies from ascites --- p.63 / Chapter 3.2.9 --- Purification of monoclonal antibodies from ascites --- p.63 / Chapter 3.2.10 --- Western blot analyses of the monoclonal antibodies --- p.64 / Chapter 3.2.11 --- Iodination of apolipoproteins --- p.64 / Chapter 3.2.12 --- Binding of the monoclonal antibody to iodinated apolipoprotein --- p.65 / Chapter 3.2.13 --- Competitive displacement analyses --- p.65 / Chapter 3.3 --- Results --- p.66 / Chapter 3.3.1 --- Development of monoclonal antibodies --- p.66 / Chapter 3.3.2 --- Purification of monoclonal antibody from ascites --- p.69 / Chapter 3.3.3 --- Western blotting analyses of AB6 and BE8 --- p.69 / Chapter 3.3.4 --- Monoclonal antibody titration curve for apolipoproteins by radioimmunoassays --- p.75 / Chapter 3.3.5 --- Competitive displacement analysis of AB6 and BE8 --- p.75 / Chapter 3.4 --- Discussion --- p.79 / Chapter Chapter 4 --- Enzyme-linked immunosorbent assay (ELISA) for ApoA-I --- p.84 / Chapter 4.1 --- Introduction --- p.84 / Chapter 4.1.1 --- Alkaline phosphatase (ALP) --- p.84 / Chapter 4.1.2 --- Conjugation methods --- p.85 / Chapter 4.1.3 --- Design of the immunoassay format --- p.87 / Chapter 4.1.4 --- Modified solid-phase: Protein A antibody-capture ELISA (PACE) --- p.87 / Chapter 4.2 --- Materials and Methods --- p.90 / Chapter 4.2.1 --- Conjugation of AB6 with maleimide activated alkaline phosphatase --- p.90 / Chapter 4.2.2 --- Titration curve of AB6-ALP conjugate --- p.90 / Chapter 4.2.3 --- Calibration curve of apoA-I sandwich ELISA --- p.91 / Chapter 4.2.4 --- Measurement of apoA-I by Protein A antibody-capture ELISA --- p.91 / Chapter 4.3 --- Results --- p.92 / Chapter 4.3.1 --- Characterization of AB6-ALP conjugate --- p.92 / Chapter 4.3.2 --- Calibration curve for the measurement of apoA-I --- p.92 / Chapter 4.4 --- Discussion --- p.95 / Chapter Chapter 5 --- General Conclusions --- p.99 / References --- p.101
164

Uso de venenos de serpentes australianas como potencial alternativa para a produção de soro anti-elapídico / Australian snake venoms as a potencial alternative for anti-elapidic serum production

Ed Carlos Santos e Silva 16 October 2015 (has links)
O soro anti-elapidico brasileiro é produzido com uma mistura de veneno de Micrurus frontalis e de M. corallinus. Estudos indicam que o soro resultante não neutraliza o veneno de algumas espécies de Micrurus. Além disso, o baixo rendimento de veneno e as dificuldades de manutenção destas serpentes em cativeiro dificultam a produção de soro. Assim, um método alternativo para a produção deste soro seria de grande valor. Estudos têm mostrado que os venenos de elapideos brasileiros contêm toxinas com um elevado grau de homologia com as de suas congêneres australianas. O presente trabalho teve como objetivo comparar inicialmente o soro brasileiro e o australiano frente ao veneno de Micrurus frontalis e M. lemniscatus. A reatividade cruzada foi testada por Western-blot e ELISA com veneno de Micrurus frontalis e a capacidade neutralizante por soroneutralização com venenos de M. frontalis, M. lemniscatus, e em parceiria com venenos de M. corallinus, M. altirostris, M. spixii, M. ibiboboca, M. fulvius, M. pyrrhocryptus , M. nigrocinctus, em camundongos. Os dados obtidos indicam nível elevado de reatividade e neutralização cruzada entre os soros. Também comparamos a imunogenicidade do veneno nativo ou irradiado, não observando diferenças nos níveis de anticorpos obtidos. As serpentes australianas utilizadas para a produção de soro são mais fáceis de manusear e produzem maiores quantidades de venenos do que as corais brasileiras. Concluímos que um soro produzido com o veneno de serpentes australianas neutraliza a atividade tóxica das Micrurus estudadas, incluindo espécies que o soro nacional não neutraliza. Assim, o uso de venenos da Austrália como imunógeno constitui alternativa viável para sanar a carência do soro nacional. / The Brazilian coral snake antivenom is produced using a mixture of Micrurus corallinus and M. frontalis venom. Several studies have shown that this serum does not neutralize the venom of some species. Furthermore, the low venom yields and the difficulties of keeping coral snakes in captivity impair antivenom production. Althought belonging to different species, coral snakes and Australian elapids share many homologous toxins in their venom. The present work aimed to compare the Brazilian and Australian antivenoms against Micrurus venom. Cross- reactivity was assayed by Western blot and ELISA, while cross-neutralization was tested in mice. Both tipes of assays indicate high levels of cross-reactivity and neutralization. We also tested the immunogenicity of native or radiation-attenuated venom and no significant difference in antibody levels was observed. The Australian snakes used for antivenom production are much easier to breed and produce higher amounts of venom that their Brazilian relatives. From this study, we conclude that a serum produced using Australian venoms neutralizes the toxicity of coral snakes venoms, including several venoms which are not neutralized by the Brazilian antivenom. Thus, the use of Australian venoms as an immunogen might solve the bottleneck of coral snake antivenom production.
165

Quantificação de dímero-D em éguas susceptíveis e resistentes à endometrite /

Mendonça, Heitor Vinícius. January 2016 (has links)
Orientador: Juliana Regina Peiró / Banca: Lina Maria Wehrle Gomide / Banca: Alexandre Secorun Borges / Resumo: A endometrite é uma das pricipais causas de redução da fertilidade em éguas. Desta forma, o diagnóstico de subfertilidade em éguas torna-se importante na tentativa de prevenir ou minimizar perdas econômicas. A quantificação de dímero-D tem sido avaliada em animais com diferentes enfermidades. Os objetivos do presente estudo foram determinar se as concentrações de dímero-D no soro e líquido uterino sofrem alteração em éguas susceptíveis à endometrite em relação a éguas resistentes antes e após lavagens uterinas seriadas e antibioticoterapia, determinar em qual compartimento o aumento do dímero-D refletiria melhor e mais rapidamente as alterações inflamatórias em éguas susceptíveis à endometrite em relação a éguas resistentes antes e após lavagens uterinas seriadas e antibioticoterapia, estabelecer valores de referência para as concentrações de dímero-D no soro e no líquido uterino de éguas resistentes e daquelas susceptíveis à endometrite e verificar se o dímero-D pode ser utilizado como um biomarcador para éguas susceptíveis à endometrite. A quantificação de dímero-D foi obtida de amostras de soro e líquido uterino de doze éguas da raça Quarto de Milha, divididas em dois grupos: éguas resistentes (grupo controle) e susceptíveis à endometrite (grupo experimental). Os resultados do presente estudo mostraram que não houve diferença entre as concentrações de dímero-D séricas ou do líquido uterino nos animais do grupo controle e experimental. Portanto, o dímero-D não pode ser util... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Endometritis is one of the main causes of fertility reduction in breeding mares. Therefore, the diagnosis of subfertility in mares becomes important in attempting to prevent or minimize economic losses. Quantification of D-dimer in animals with a variety of diseases has been published. The goals of this study were to determine whether D-dimer concentrations in serum and uterine fluid suffer changes in mares susceptible or resistant to endometritis before and after serial uterine washes in association with antibiotic therapy, to determine in which compartment increased D-dimer concentrations would reflect better and faster the inflammatory changes in mares susceptible to endometritis in comparison to resistant mares before and after serial uterine washes and antibiotic therapy, to establish reference values for concentrations of D-dimer in serum and uterine fluid of resistant mares and those susceptible to endometritis, and to verify whether D-dimer can be used as a biomarker in mares susceptible to endometritis. D-dimer was quantified in serum or uterine fluid of twelve Quarter Horses mares, divided into two groups: mares resistant to (control group) or susceptible to endometritis (experimental group). The results of this study showed no difference between serum or uterine fluid concentrations of serum D-dimer between groups. We concluded that D-dimer cannot be used as a biomarker to identify mares susceptible to endometritis. / Mestre
166

Ex Vivo Protein Post Translational Modifications in Poorly Stored Blood Plasma and Serum and their use as Markers of Biospecimen Integrity

January 2018 (has links)
abstract: Exposure of blood plasma/serum (P/S) to thawed conditions, greater than -30°C, can produce biomolecular changes that misleadingly impact measurements of clinical markers within archived samples. Reported here is a low sample-volume, dilute-and-shoot, intact protein mass spectrometric assay of albumin proteoforms called “ΔS-Cys-Albumin” that quantifies cumulative exposure of archived P/S samples to thawed conditions. The assay uses the fact that S-cysteinylation (oxidation) of albumin in P/S increases to a maximum value when exposed to temperatures greater than -30°C. The multi-reaction rate law that governs this albumin S-cysteinylation formation in P/S was determined and was shown to predict the rate of formation of S-cysteinylated albumin in P/S samples—a step that enables back-calculation of the time at which unknown P/S specimens have been exposed to room temperature. To emphasize the capability of this assay, a blind challenge demonstrated the ability of ΔS-Cys-Albumin to detect exposure of individual and grouped P/S samples to unfavorable storage conditions. The assay was also capable of detecting an anomaly in a case study of nominally pristine serum samples collected under NIH-sponsorship, demonstrating that empirical evidence is required to guarantee accurate knowledge of archived P/S biospecimen storage history. The ex vivo glycation of human serum albumin was also investigated showing that P/S samples stored above their freezing point leads to significant increases in glycated albumin. These increases were found to occur within hours at room temperature, and within days at -20 °C. These increases continued over a period of 1-2 weeks at room temperature and over 200 days at -20 °C, ultimately resulting in a doubling of glycated albumin in both healthy and diabetic patients. It was also shown that samples stored at lower surface area-to-volume ratios or incubated under a nitrogen atmosphere experienced less rapid glucose adduction of albumin—suggesting a role for oxidative glycation in the ex vivo glycation of albumin. / Dissertation/Thesis / Doctoral Dissertation Biochemistry 2018
167

Avaliação do desempenho diagnóstico do teste ELISA para a cisticercose em inquéritos sorológicos / Evaluation of performance diagnostic of the ELISA test for cysticercosis in inquiries sorologycal

Lago, Eloi Marcos de Oliveira 30 August 2007 (has links)
O diagnóstico sorológico da cisticercose vem se destacando como uma fonte alternativa seguramente eficaz ao estudo da doença. Com a proposta de acessibilidade, devido primordialmente a relação custo, os testes ELISA são promissores à pesquisa sorológica de campo. O problema iminente está na utilização de extratos antigênicos capazes de gerar ao teste, parâmetros compatíveis para a pesquisa de anticorpos na população de baixa prevalência. Nesse contexto, o presente trabalho objetivou a avaliação de um teste ELISA com alto valor preditivo positivo (VPP) para a pesquisa de anticorpos anti-cisticercos de Taenia solium em inquéritos sorológicos na população geral. Os antígenos ensaiados foram proteína 18/14 kDa de líquido vesicular de T. crassiceps (18/14-Tcra), liquido vesicular de T. crassiceps (LV-Tcra) e total de cisticercos de T. solium (T-Tso), respectivamente estes constituíram os testes ELISA-18/14, ELISA-Tcra e ELISA-Tso. Foram ensaiadas 610 amostras de soro de indivíduos supostamente saudáveis e 20 amostras de soro de indivíduos com neurocisticercose confirmados por critérios clínicos e laboratoriais. Após os ensaios, o teste ELISA-18/14 apresentou sensibilidade e especificidade de 100% e mesmo em diferentes prováveis prevalências (0,1; 0,5; 1,0 e 5,0%) o VPP e o valor preditivo negativo (VPN) foram fixados também em 100%. A repetitividade das leituras do teste expressa em coeficiente de variação apresentou-se entre 16 e 18%. O teste ELISA-Tcra não demonstrou o mesmo desempenho, a especificidade foi calculada em 96,3% e o VPP variou entre 2,6 a 59,3% para prevalências de 0,1 a 5,0%; quanto à sensibilidade e VPN houve similaridade entre os resultados. O ELISATso apresentou resultados ainda menos expressivos, a especificidade foi calculada em 95,7% e o VPP variou entre 2,3 a 55% para as prevalências de 0,1 a 5,0%; essa redução na especificidade se dá pelo aumento do número de resultados falso-positivos no teste em conseqüência da expressão de proteínas de alto peso molecular. Através dos parâmetros avaliados fica notório o desempenho promissor do teste ELISA-18/14 na pesquisa de anticorpos anti-cisticercos de Taenia solium em inquéritos sorológicos da população geral. / The serum diagnosis of cyticercosis has been highlighted as an efficient alternative source in the study of the disease. With an accessability proposal , due to the expense, the ELISA´s tests are promising to the serum´s field research. This problem makes necessary the use of antigens extracts able to give the test, trusted and compatible parameters to the research of antibodies in the population of low prevalence. In this context, this current work stablished the evaluation of the ELISA´s test with a high predictive value positive(PPV) to the anti-cysticerci of Taenia solium antibodies research in a serum inquiry of the general population. The antigens tested were the 18/14 kDa protein of the vesicular liquid of T. crassiceps (18/14-Tcra), the vesicular liquid of T. crassiceps (LV-Tcra) and the total of T.solium (T-Tso). That constituted in the ELISA 18/14, ELISATcra and ELISA-Tso test respectively. There were 610 sample of serum were tested of healthy people and 20 samples of serum with confirmed neurocysticercosis by clinical and laboratorial criterias. After these tests, the ELISA´s test showed sensibility and specificity in 100% of the cases, even in different prevalences (0,1; 0,5; 1,0 and 5,0%) the VPP and the predictive value negative (VPN) were also fixed in 100%. The repetition of the test expressed in variation coefficient occurred between 16 and 18% of the cases. The ELISATcra didn´t show the same development, the specificity were calculation in 96,3% and the VPP wanted between 2,6 and 59,3% to the prevalences of 0,1 to 5,0%; there were similarities of the results of sensibility and VPP. The ELISA-Tso showed less important results the specificity was calculated in 95,7% and the VPP between 2,3 and 55,0% to the prevalences of 0,1 to 5,0%, this reduction of specificity is due to the increase of the number of false-positive results in the test because of the expression of proteins of high molecular weight. Through these parameters it´s clear the promising development of the ELISA-18/14 test, as been arbitrary in the studies of serology inquiry in the general population.
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Human exposure to organohalogen compounds in the Faroe Islands

Fängström, Britta January 2005 (has links)
<p>The Faroe Islands in the North Atlantic are part of the sub-Arctic region, a remote region far from industrial activity. In spite of this remoteness, the Islands are not a sanctuary: exposures and effects of environmental pollutants mar its natural beauty and wildlife. In the Arctic regions, fish, sea mammals and seabirds have shown to contain elevated levels of the classical persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), as well as more recent POPs such as the polybrominated diphenyl ethers (PBDEs). Human populations living in the Arctic regions are usually highly dependent on seafood and seabirds as food sources, and diet becomes their major source of exposures to POPs. As reported in the 1980’s, residents of the Faroe Islands were shown to have high concentrations of organohalogen substances (OHS) in their breast milk. Long-finned pilot whales (<i>Globicephala melas</i>) blubber and meat have been shown to be a major source of OHS exposure for some of the Faroe Islanders.</p><p>The main objective of this thesis is to investigate the sources and concentrations of some POPs and their metabolites for the Faroese population. First, human milk and serum from pregnant women (mothers) and children were analyzed for PBDEs, PCBs, and polychlorinated biphenylols (OH-PCB), the major PCB metabolites. Second, POPs were measured in seabirds, i.e. PCBs in fulmars (<i>Fulmarus glacialis</i>) and guillemots (<i>Uria algae</i>), and PBDEs in fulmars to search for other potential sources of POPs exposure.</p><p>The results reinforce previous findings that part of the Faroe Island population is highly exposed to OHS. Median concentrations (430 ng/g lipid weight (l.w.) of CB-153) in maternal serum (1994-95) are among the highest in the world. Serum concentrations of CB-153 in children (age 7, samples collected in the early 2000’s) were approximately 90% of those in the mothers, sampled 1994-95. Similarly high CB-153 concentrations (380 ng/g l.w.) were measured in samples of mother’s milk, collected in 1999. The OH-PCB concentrations were also high in segments of the population, with 2.9 ng/g fresh weight as the sum of five OH-PCBs. Except for 4-OH-CB107, concentrations of OH-PCBs were generally lower in children than in mothers.</p><p>The ΣPBDE median concentrations in maternal serum and human milk (1999) are at the higher end of those reported in Europe, with levels of 9.5 and 8.2 ng/g l.w. respectively. ΣPBDE levels increase in human milk samples collected at three different time points (1987-1999), mainly due to increasing BDE-153 concentrations. The range of serum ΣPBDE concentrations in mothers and children are similar, although the congener patterns show differences. BDE-47 is the dominant congener in maternal serum, while BDE-153 is the major congener in children. The differences seen in PBDE congener patterns may arise differences in dates of sampling (7 years) for the two populations, maternal serum sampled in 1994-95 and children serum sampled in 2000-01, rather than from differences in uptake/metabolism or in contemporary exposures.</p><p>PCB concentrations in fulmars and pilot whales show similar ranges. In contrast, PBDE concentrations are 100 times higher in pilot whales than in fulmars. Consequently, Faroese may be especially exposed to PCBs via consumption of fulmars and fulmar eggs, while the exposure to PBDEs is less pronounced.</p><p>Results from this thesis highlight the pronounced exposures to PCBs, OH-PCBs, and PBDEs among residents of the Faroe Islands, a remote region in the Northern Atlantic far away from industrial and urban sources of pollution.</p>
169

What is the optimum diet for asymptomatic HIV-infected people (AHIV)? : a public health approach / Averalda van Graan

Van Graan, Averalda Eldorine January 2007 (has links)
Thesis (Ph.D. (Nutrition))--North-West University, Potchefstroom Campus, 2007.
170

Heparan Sulfate Dependent Mechanisms of Amyloidosis

Noborn, Fredrik January 2012 (has links)
A common theme in amyloid disorders is the deposition of disease-specific protein aggregates in tissues. Amyloid proteins bind to heparan sulfate (HS), a sulfated glycosaminoglycan, and HS has been found to promote the aggregation process. The present work relates to HS mediated mechanisms of amyloidosis, particularly transthyretin (TTR) amyloidosis, AA-amyloidosis and Alzheimer’s disease (AD). TTR is a transport protein present in the blood and cerebrospinal fluid, which under unclear circumstances can deposit as amyloid in the myocardium of elderly individuals. Examination of cardiac tissue from a 70 year old patient with reported cardiomyopathy reveald co-deposition of TTR amyloid and HS. Studies revealed that HS promotes TTR fibrillization through interaction with a basic motif in the protein. Empolyment of a cell model demonstrated that cell surface HS mediates internalization of TTR, an effect likely facilitated by HS-binding to the basic motif on TTR. Collectively, HS-TTR interactions at the cell surface may have dual outcomes, resulting in either fibrillization or internalization, respectively. During inflammatory conditions, serum amyloid A (SAA), an acute-phase protein associated with the high-density lipoprotein (HDL), can assemble into insoluble amyloid fibrils, causing AA-amyloidosis. We found that HS structures exceeding 12-14 sugar units in length separates SAA from HDL and induces subsequent aggregation of the polypeptide. Our result proposes a novel role for HS in AA-amyloidosis in which a critical length of HS is required for separation of SAA from HDL. Late-onset AD patients show reduced ability to clear cerebral amyloid-β (Aβ) aggregates, a pathological hallmark of the disease. Althought the pathway of Aβ clearance is still unclear, several cell-surface receptors are implicated in Aβ internalization. We found that ApoE facilitated Aβ uptake through interactions with HS-proteoglycans and low-density lipoprotein receptor-related protein 1. The ApoE interaction with Aβ likely promotes Aβ clearance in the brain, but, if unbalanced, may contribute to the pathology of AD.     These findings are in accord with the concept of HS as a promoter of amyloid protein aggregation, but also point to more complex relationship.

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