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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.
181

Evaluation of Escherichia coli probiotic candidates for combating EHEC in the food chain using competition analysis in bovine feces

Stigers, Linnea January 2018 (has links)
Enterohemorrhagic E. coli, EHEC, is a verotoxin producing, zoonotic pathogen, which causes diseases in humans such as bloody or watery diarrhea. Microorganisms compete for limited living space, nutrients and other resources and therefore other microorganisms are EHECs biggest competitors. To avoid outbreaks and infections with EHEC, one possible approach is to use harmless but competitive bacteria as probiotics. Therefore, the aim of this study was to evaluate three probiotic E. coli strains and their ability to outcompete EHEC in bovine feces.     Ten different cattle fecal samples from three different farms were used to mix with the three probiotic and EHEC strains. The mixture was diluted and cultivated at 0 h as a control and then incubated for 48 h at 20°C and 37°C before dilution and cultivation on CT-SMaC. Colonies was counted and ratios between EHEC and probiotic E. coli before and after incubation were calculated. Kruskal-Wallis test with Dunn’s test as post hoc test were used to see if observed reductions of EHEC were significant or not.     In 37°C, strain 10 was the only strain producing a significant reduction of EHEC. In contrast, no significant reduction was observed at 20°C in any of the strains.     Future research studying other factors and performed on live cattle models are necessary to confirm the usefulness of the studied probiotic candidates. However, these results indicate probiotics can be a useful tool to avoid infections and big outbreaks of EHEC in the future.
182

Development of a dynamic ex vivo culture system for human islets of langerhans

Hammarbäck, Madelene January 2018 (has links)
Type 1 diabetes(T1D)is a disease that only gets more common. The etiology of the disease is not known but there are many existing theories about what the cause is. These different theories have been tested in vivoin rodents or invitro. The resultsfrom experiments done in those waysarenotall realistic because rodents differnotablyfrom humans,and when studies areperformed in vitrowith human isletsof Langerhans different hormones will accumulate. The aim of this studywas to establisha dynamic ex vivosystem in which stimulation of human islets of Langerhans can be performed in a more lifelike environment. To study islets in this system couldin the future lead to increased knowledge in the etiology of T1D.The perifusion system PERI-4.2 from Biorep Technologies together with an incubator with 37°Cand5% CO2were used to arrangethe ex vivosystem. An Insulin ELISA from Mercodia was performedto analyze the insulin secretion from the islets. Fourdifferent set ups for the system were tested and the last one showed the best results.In conclusion this study has shown that it is possible to preserve human islets of Langerhans in a dynamic ex vivosystem with a constant medium exchange if it is done under conditionswhere the islets are protected from shear forces from the supplying medium,together with a medium exchange rate which replaces the whole medium in at least one hour.
183

Evaluation of an equine-optimized enzyme-linked immunosorbent assay for the determination of serum insulin in canine and feline samples

Moberg, Ylva January 2018 (has links)
Background: Insulin is an important hormone for glucose homeostasis. It is released from β-cells in the endocrine pancreas as a response to increased concentrations of plasma glucose. The major effect of insulin is the facilitation of cellular uptake and storage of glucose as glycogen. Insulinomas are tumours that produce excessive amounts of insulin resulting in hypoglycaemia. The condition has been observed in dogs and cats and is often malignant. One part of establishing the diagnosis is confirmation of elevated concentrations of insulin in a hypoglycaemic sample. Aim: The aim of this study was to evaluate if an equine-optimized insulin ELISA (Mercodia AB, Uppsala, Sweden) is useful for analysis of insulin in canine and feline serum samples when insulinoma is suspected. Material and methods: All samples were analysed with Equine insulin ELISA. Precision, linearity and effects of haemolysis were studied. The stability of insulin was evaluated after storage in 4°C, room temperature and after repeated freezing and thawing. A reference interval was constructed for both canine and feline samples. Results: Total precision expressed as CV was 4.4 – 18.9 %. The method was linear up to at least 100 mU/L for dogs and 15 mU/L for cats. Reference interval for cats was <11.6 mU/L, due to few healthy animals no reference interval for dogs could be established. Stability was acceptable for up to four days. No effects of haemolysis were detected. Conclusion: Mercodia Equine insulin ELISA is suitable for analysis of insulin in serum from dogs and cats when suspecting insulinoma.
184

Comparison of two HPLC columns: An attempt to improve analysis of carbohydrate-deficient transferrin

Engström, Ida January 2018 (has links)
1ABSTRACTCarbohydrate-deficient transferrin (CDT) is a biomarker for excessive and long-running intake of alcohol. It is a form of transferrin called disialotransferrin that under normal circumstances is <2 % of total transferrin in human blood. An increase is seen when alcohol consumption exceeds450 g per week. CDT is analyzed in serum usinghigh performance liquid chromatography (HPLC) and UV/VIS detection. The purpose of this study was to investigate if an “in routine” method could be improved by switching columns.With ion exchange chromatography transferrin glycoforms are separated and quantified. The carbohydrate-deficient transferrin glycoforms have an isoelectric point between 5,7-5,9 that depends on the number of sialic acids on the molecule. With the use of a salt gradient and pH above the isoelectric point the glycoforms can beseparated depending on their affinity to the stationary phase. Batches with patient and control serum was first analyzed on the routine column Source 15Q PE and then on the alternative column Reprospher 200 SAX 5μm.Student’s t-test showed that the two methods’results correlated but were significantly different. A Bland-Altman plot illustrated differences between the two columns. High and low control serum values from Reprospher were lower than the accepted interval. In this study Reprospher’s stationary phase seemed to be affected to such an extent that stabile retention time, better resolution, and stabile values could not be achieved and because the information about the column was lacking an attempt to regeneratethe columnwas not conducted.
185

A spectrophotometric method to analyze antibiotics in plasma: A validation study

Lindman, Elin January 2018 (has links)
Antibiotic resistance is one of the most serious medical problems in the world. To counteract the increase in antibiotic resistance, new rapid and effective analytical methods are needed. To effectively treat infections in critically ill patients, optimal antibiotic dosages are required. DrugLog® is an instrument that uses a spectrophotometric method to analyze antibiotics in plasma in the wavelength range 200-800 nm. The aim of this study was to do a method validation of the instrument DrugLog®.     The study material that was used was whole blood from healthy donor and routine citrate plasma samples from the laboratory. The precision of the method and stability of plasma, the best way to filtrate lipids from plasma and four antibiotics (meropenem, cefotaxime, vancomycin, piperacillin/tazobactam) were investigated.     The precision of the method, measured as CV% was less than 0.62 and stability plasma showed a CV% of 135.74 after 24 h in room temperature. The stability for the different antibiotics after 24 h in room temperature showed a CV% of 8.11 for meropenem, 40.80 for vancomycin, 16.55 for cefotaxime and 2.92 for the combination antibiotic piperacillin/tazobactam. It was also determined that bacterial filter was the best way to remove lipids from plasma.     In conclusion DrugLog® is a suitable instrument to analyze concentration of antibiotics in patients during antibiotic treatment, however further validations are needed.
186

The Effect of Contrast Media on Several Common Laboratory Assays

Johansson, Isabelle January 2018 (has links)
Contrast media are commonly used as an enhancement in several diagnostic imaging methods, which in today’s healthcare often are combined with blood works in diagnostics and surgical preparations, as well as to follow up on the patient’s recovery. To save time and money for both the hospital and the patients themselves, the ability to carry out both the radiological examination and the blood works within the same hospital visit would be preferred. However, there have been indications of a potential interference from the contrast media used, and therefore a waiting period is in place. The aim of this study was therefore to see if that waiting period was warranted by testing if contrast media does cause a significant interference in the most common analyses. This was investigated by infusing pooled samples with either iohexol or gadoteric acid, the active components of the most common contrast agents, at either a full dosage or a half dosage. These samples were then run by standard protocol and the results compared to control samples. The results showed that while some analyses proved affected, others proved unaffected or only insignificantly so. Some of the affected analyses were sodium, activated partial thrombin time and hemoglobin. While some analyses such as prostate specific antigen and prothrombin time were unaffected. Analysis of more samples is necessary to confirm the results, but the overall consensus is that while most analyses are unaffected the effects are too large and uncertain to comfortably disregard the waiting time.
187

A comparative study of immunofluorescence, zinc sulphate centrifugal flotation and FASTest®GIARDIA strip for detection of Giardia in dogs and cats

Salih, Baraah January 2018 (has links)
Giardia intestinalis is the most common parasite found in dogs and cats. It is traditionally diagnosed using a microscope. These methods include direct immunofluorescence, DIF, and zinc sulphate centrifugal flotation, ZnSO4 C-flotation. However, there are commercially available SNAP tests such as the FASTest® GIARDIA strip that is often used by dogs and cats owner to detect Giardia. The aim of this study was to compare the sensitivity, cost and labor intensity of these three methods for detection of Giardia. To investigate this, 150 samples from dogs and cats were examined at the National Veterinary Institute in Sweden. The samples were a mixture of diarrheic and non-diarrheic stool. Of the 150 stool samples 100 samples were examined with FASTest® GIARDIA strip while 150 samples were examined with DIF and ZnSO4 C-flotation. The results indicated that FASTest® GIARDIA strip had a sensitivity of 66.18 %, a cost of 100 Swedish crowns (SEK) per sample and was the easiest test to use. ZnSO4 C-flotation had a sensitivity of 89.90 %, cost 418.75 SEK and took about 15 minutes to perform. DIF had 100 % sensitivity and specificity and due to that it was used as a standard reference method. The cost for DIF was 300 SEK and took more than an hour to perform per sample. The conclusion from this study is that, FASTest® GIARDIA strip is not a recommended test for detection of Giardia despite their low cost and easiness to use. DIF and ZnSO4 C-flotation remain a better diagnostic option for detection of Giardia.
188

Metodoptimering för sekvensering av S-segmentet i Puumalavirus från human plasma / Optimization of Methods for Sequencing of the S-segment in Puumala Virus from Human Plasma

Pettersson, Cecilia January 2018 (has links)
No description available.
189

Sex minuters gångtest och simulerad flygresa hos patienter med KOL / Six Minute Walktest and Flight Simulation in Patients with COPD

Svensson, Maria January 2018 (has links)
No description available.
190

Detektion av alloantikroppar hos nyligt transfunderade DAT-positiva patienter : Utvärdering med en experimentell in vitro modell / Detection of Alloantibodies in Recently Transfused DAT-Positive Patients : Evaluation with an Experimental in vitro Model

Bixo, Mi January 2018 (has links)
No description available.

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