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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Study of the insulin-like peptide 3 in human platelets

Borg, Mathias January 2009 (has links)
The insulin-like 3 peptide is autocrine/paracrine insulin-related hormone with a size of approximately 6kDa [1]. It mediates through a leucine richG-coupled receptor named LGR8. INSL3 is mainly expressed in human Leydig cells and is directly responsible for migration of the testis during the pre-natal period in maledevelopment. [2] INSL3 mRNA has recently been verified in human platelets whereas no mRNA has been detected for LGR8 (by Sanofi-Aventis GmbH in Frankfurt,Germany), indicating that INSL3 might be released through paracrine functions at sites of platelet adhesion and aggregation upon a vascular injury.Furthermore, has activated platelets been shown to translate essential proteins upon activation, in a term called “signal-dependent protein synthesis”.The B-Cell lymphoma-3 protein (BCL-3) is an example of such a protein [3], and there is a possibility that INSL3 might be also. In this thesis we wanted to detect the relaxin- like peptide 3 hormone (INSL3). (Its function, location and the timeframe of its release, when/if it issecreated in stimulated platelets).The source of platelet-derived INSL3 can be found with Western blotting and Enzyme immunoassay. Detection of the insulin-like 3 peptide in human platelets turned out to be a difficult challenge due to the small amount of INSL3 secretion uponplatelet activation; hence the total amount of INSL3 produced might be below detection limit.
32

Analysis of CD4+ and CD8+ T-lymphocytes : A comparison between EPICS XL and Celldyn Sapphire

Yazdan Panah, Haleh January 2006 (has links)
Flowcytometric technology has been widely used for measurement of the absolute numbers of T-lymphocytes subsets in Human Immunodeficiency virus (HIV), defining the disease state, monitoring antiviral treatment, and identifying any risk for opportunistic infections. A manual preparing of the samples is required. More recently an automated and enclosed blood cell counting, Celldyn Sapphire has been introduced. In this study the performance of the Flow cytometer EPICS XL as a reference method for analysis of CD3+, CD4+ and CD8 T-lymphocytes was evaluated with blood from 40 individual’s samples. EPICS XL was also compared with Celldyn Sapphire in the analysis of T-lymphocyte subsets in 39 blood samples from patients with low, high and normal lymphocyte counts. The result showed that the precision was high for both EPICS XL (2.5%) and Celldyn (10%). The method was linear over a wide range. Comparisons of CD3+, CD4+, and CD8+ T-lymphocytes analysis showed high coefficients of correlation (r0.9) and agreement (y>0.9x) between two instruments. A lower degree of agreement was observed at low concentration of CD3+ and CD4+ T-lymphocytes (0.757, 0.739). This means that cell counts obtained by Celldyn were 30% lower than those obtained with EPICS XL. This study shows that both EPICS XL and Celldyn Sapphire were suitable for CD4+ and CD8+ T cell counts. It is however preferable to use Flowcytometry for counting of low concentration of CD4+ T-lymphocytes (<200 cells/µL).
33

External Quality Assessment of HbA1c for Point of Care Testing

Bjuhr, Mathias, Berne, Christian, Larsson, Anders January 2005 (has links)
Objectives: To evaluate the long term total imprecision of HbA1c testing within the county of Uppsala in relation to the Swedish analytical goal of coefficient of variation (CV) <3% for HbA1c and to study the cost of an external quality assurance program for point-of-care HbA1c The county uses Bayer DCA 2000™ for point-of care HbA1c testing currently having 23 of these instruments. Methods: Method imprecision was assessed by analysis of patient samples performed as split samples during a 3 year period (2002-2004) as part of the quality assurance program for point-of-care HbA1c testing. The samples were first analysed on a Bayer DCA 2000™ and the samples were then sent to the centralised laboratory for reanalysis with an HPLC system (Variant II™, Biorad). The testing was performed approximately 8 times per year with each instrument. Results: The median CV between the HPLC method and the point-of-care instruments for each unit was slightly higher than 3%. Conclusion: The DCA 2000™ systems have an acceptable imprecision and agreement with the central laboratory. The test results show acceptable agreements within the county regardless where the patient is tested. The cost of the external quality assurance program is calculated to be approximately SEK 1340 (Euro 150) per instrument.
34

THE EXPRESSION OF THROMBOMODULIN, TISSUE FACTOR, TISSUE FACTOR PATHWAY INHIBITOR AND ENDOTHELIAL PROTEIN C RECEPTOR IN NORMAL AND IUGR PLACENTA

Källebring, Tina January 2005 (has links)
The aim of this study was to examine the expression of Thrombomodulin, Tissue Factor, Tissue Factor Pathway Inhibitor and Endothelial Protein C Receptor in placenta throughout the three phases of the third trimester in the normal placenta and in IUGR placenta from full term. Twenty-five normal placenta samples and twenty-five IUGR placenta samples were obtained and each sample was stained by immunohistochemistry using monoclonal antibodies. Each antibody was optimised for antigen retrieval method and for optimal dilution, before been applied to the test tissue. The results showed that each of the antibodies mentioned was expressed in normal placenta and in IUGR placenta. No significant difference could be established concerning the expression of each antibody mentioned between normal and IUGR placenta.
35

Measurement and validation of urinary cystatin C by particle-enhanced turbidimetric immunoassay on Architect ci8200

Hikmet Noraddin, Feria January 2011 (has links)
Cystatin C, a 13 kDa low molecular weight protein is an inhibitor of cysteine proteases. Due to its low molecular weight and positive charge at physiological pH, it is freely filtered by the glomerulus and catabolized after reabsorption by proximal tubular cells with a low concentration (0.03-0.3 mg/L) in urine amongst healthy subjects. Urinary cystatin C is a potential biomarker detection of acute kidney injury (AKI) in the acute phase when patients are submitted to the intensive care unit. The aim in this report was to perform a full method validation of urinary analysis of cystatin C on a high throughput chemical analyzer by particle-enhanced turbidimetric immunoassay (PETIA) at the University Hospital in Uppsala, Sweden. The antigen excess, linearity, lower limit of quantification (LoQ), recovery, assay precision, stability and interference caused by haemoglobin was evaluated. No hook effect was observed, the assay was linear over the studied interval <0.001-0.950 mg/L with a regression of R2=0.9994. The LoQ was calculated to 0.020 mg/L with a coefficient of variation (CV) ≤10% which was considered acceptable. The assay had a recovery between 93-100% and the assay precision had a total CV <3.5%. Cystatin C is stable for 3 days in room temperature and 14 days in +4C. The assay did not show any major interference with haemoglobin. The urinary cystatin C showed good precision and performance characteristics by measurements using PETIA all of which is a necessary qualification for a biomarker at a 24-h running routine laboratory.
36

Comparison of Different Electrophoretic Methods for Haptoglobin Phenotyping and an Investigation in Patients with Abdominal Aortic Aneurysm

Hellman, Jana January 2011 (has links)
Haptoglobin is an acute phase protein with important biological role because of its capacity to bind to haemoglobin. Haptoglobin exists in three major genetic polymorphism types: Hp1-1, Hp2-1 and Hp2-2, the distribution of which has been associated with abdominal aortic aneurysm (AAA), an asymptomatic aortic disease common among men older than 65 years.    Five different electrophoretic methods were tested according to their ability to separate the haptoglobin phenotypes. The detection was based on a produced hemolysate of blood in which haemoglobin binds to haptoglobin thereby forming a complex that can be detected by specific haemoglobin staining using TMB-dihydrochloride and hydro peroxide as substrate resulting in an azure-green color of the bands. Samples from 15 patients who had suffered surgery for not broken AAA, that is more than5.0 cmaortic diameter, and 15 samples from matched controls were analyzed.    Among the five tested electrophoretic methods best migration and separation was seen on the pre-cast agarosgel Hydragel HR on the instrument Hydrasys. The other four methods gave less successful results. This pilot investigation showed the following distribution of the phenotypes of haptoglobin among AAA patients; 7 % Hp1-1, 40 % Hp2-1 and 53 % Hp2-2 and for the controls; 13 % Hp1-1, 33 % Hp2-1 and 53 % Hp2-2.    In conclusion, the used techniques has to be further optimized and more patients have to be included in the study before it can be ascertained if the phenotypes of Haptoglobin play any role in the progress of the AAA disease.
37

Comparison between four commonly used methods for detection of small M-components in plasma

Jonsson, Susanne January 2008 (has links)
Analysis of M-components is an important part of the diagnosis of monoclonal gammopathies and for the evaluation of disease response during treatment. In this project, two widely used electrophoresis methods and their corresponding immunotyping method were compared to evaluate the sensitivity of each method for the detection of small M-components. The project included 30 plasma samples from patients with identified M-components; 10 samples containing each IgG, IgA and IgM, respectively. All samples were diluted with normal EDTA plasma to achieve M-components of 5,00g/L. The samples were then serially diluted to achieve M-component concentrations of; 5,00, 2,50, 1,25, 0,63, 0,31 and 0,16g/L. All 180 samples were analysed with agarose gel electrophoresis and capillary electrophoresis. The dilutions above and below the detection level of each method were then analysed with immunofixation and immunosubtraction. The results showed good agreement between agarose gel electrophoresis and capillary electrophoresis in the highest concentrations of IgG and IgM. With agarose gel electrophoresis, IgA was detected in the same location as transferrin and the lowest concentration detected were therefore 1,25g/L. Besides the samples containing IgG, immunofixation was the most sensitive method.
38

Evaluation of platelet parameters from Advia 2120 and Sysmex XT-2000iV in samples from dogs, horses and cats.

Mitander, Maria January 2008 (has links)
Haematology instruments using optical and fluorescence techniques have improved the platelet count in domestic animals. There are still some difficulties present, especially when counting cat thrombocytes due to their ability to aggregate and the occurrence of large platelets. The objective of this study was to evaluate and compare the platelet count, mean platelet volume and platelet crit in dogs, horses and cats on Advia 2120 and Sysmex XT-2000iV. Fresh blood samples from 64 dogs, 40 horses and 39 cats with various medical conditions were analysed on both instruments. Manual blood smears of all feline samples were scrutiniously analysed to evaluate the aggregation warning flag from Advia. There was good agreement between the instruments for the optical platelet count in dogs and cats. Slightly higher values were reported from Advia. Samples from horses presented poor correlations for all studied parameters. Platelet clumps appeared in 70% of the 37 scrutinized feline blood smears, while 46% of the samples generated aggregation warning flags from the Advia instrument. Advia and Sysmex showed good agreement for platelet counts in blood from dogs and cats. Mean platelet volume and platelet crit need further evaluation before conclusions can be made concerning their clinical relevance. The sensitivity of the platelet aggregation warning flag from the Advia instument needs further elevation.
39

Digital Microfluidics: A Versatile Platform For Applications in Chemistry, Biology and Medicine

Jebrail, Mais J. 31 August 2011 (has links)
Digital microfluidics (DMF) has recently emerged as a popular technology for a wide range of applications. In DMF, nL-mL droplets containing samples and reagents are controlled(i.e., moved, merged, mixed, and dispensed from reservoirs) by applying a series of electrical potentials to an array of electrodes coated with a hydrophobic insulator. DMF is distinct from microchannel-based fluidics as it allows for precise control over multiple reagent phases (liquid and solid) in heterogeneous systems with no need for complex networks of microvalves. In this thesis, digital microfluidics has been applied to address key challenges in the fields of chemistry, biology and medicine. For applications in chemistry, the first two-plate digital microfluidic platform for synchronized chemical synthesis is reported. The new method, which was applied to synthesizing peptide macrocycles, is fast and amenable to automation, and is convenient for parallel scale fluid handling in a straightforward manner. For applications in biology, I present the first DMF-based method for extraction of proteins (via precipitation) in serum and cell lysate. The performance of the new method was comparable to that of conventional techniques, with the advantages of automation and reduced analysis time. The results suggest great potential for digital microfluidics for proteomic biomarker discovery. Furthermore, I integrated DMF with microchannels for in-line biological sample processing and separations. Finally, for applications in medicine, I developed the first microfluidic method for sample clean-up and extraction of estrogen from one-microliter droplets of breast tissue homogenates, blood, and serum. The new method is fast and automated, and features >1000x reduction in sample use relative to conventional techniques. This method has significant potential for applications in endocrinology and breast cancer risk reduction. In addition, I describe a new microfluidic system incorporating a digital microfluidic platform for on-chip blood spotting and processing, and a microchannel emitter for direct analysis by mass spectrometry. The new method is fast, robust, precise, and is capable of quantifying analytes associated with common congenital disorders such as homocystinuria, phenylketonuria, and tyrosinemia.
40

Digital Microfluidics: A Versatile Platform For Applications in Chemistry, Biology and Medicine

Jebrail, Mais J. 31 August 2011 (has links)
Digital microfluidics (DMF) has recently emerged as a popular technology for a wide range of applications. In DMF, nL-mL droplets containing samples and reagents are controlled(i.e., moved, merged, mixed, and dispensed from reservoirs) by applying a series of electrical potentials to an array of electrodes coated with a hydrophobic insulator. DMF is distinct from microchannel-based fluidics as it allows for precise control over multiple reagent phases (liquid and solid) in heterogeneous systems with no need for complex networks of microvalves. In this thesis, digital microfluidics has been applied to address key challenges in the fields of chemistry, biology and medicine. For applications in chemistry, the first two-plate digital microfluidic platform for synchronized chemical synthesis is reported. The new method, which was applied to synthesizing peptide macrocycles, is fast and amenable to automation, and is convenient for parallel scale fluid handling in a straightforward manner. For applications in biology, I present the first DMF-based method for extraction of proteins (via precipitation) in serum and cell lysate. The performance of the new method was comparable to that of conventional techniques, with the advantages of automation and reduced analysis time. The results suggest great potential for digital microfluidics for proteomic biomarker discovery. Furthermore, I integrated DMF with microchannels for in-line biological sample processing and separations. Finally, for applications in medicine, I developed the first microfluidic method for sample clean-up and extraction of estrogen from one-microliter droplets of breast tissue homogenates, blood, and serum. The new method is fast and automated, and features >1000x reduction in sample use relative to conventional techniques. This method has significant potential for applications in endocrinology and breast cancer risk reduction. In addition, I describe a new microfluidic system incorporating a digital microfluidic platform for on-chip blood spotting and processing, and a microchannel emitter for direct analysis by mass spectrometry. The new method is fast, robust, precise, and is capable of quantifying analytes associated with common congenital disorders such as homocystinuria, phenylketonuria, and tyrosinemia.

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