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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.
631

TOWARDS BIOMARKER DISCOVERY IN CONGENITAL URINARY TRACT OBSTRUCTION

Orton, Dennis 09 May 2014 (has links)
Proteome analysis techonologies are commonly employed for discovery-based biomarker identification studies. This thesis aims to help bridge the gap between analytical technology development and clinical application by improving and appling a proteomics workflow for biomarker discovery in congenital urinary tract obstruction (UTO). By accentuating the importance of experimental design, and evaluating the biological relevance of quantitative proteome analyses, the results of this research provide confidence in a number of identified candidate biomarkers of UTO. A sensitive method for quantification of proteome samples was developed using temperature controlled reversed-phase liquid chromatography (TPLC). The TPLC system provides high recovery (> 90 %), as well as high accuracy and precision in estimating the concentration across a number of protein sample types (CV < 10 %). The need for extensive fractionation strategies coupled with LC-MS analysis challenges the throughput of the overall experiment. Development of a dual column LC-MS interface reduced the total analysis time by a factor of 2 over conventional single column LC-MS systems. The system was applied to a quantitative proteome analysis of proximal tubule cells exposed to mechanical stretch, mimicking the conditions they experience during UTO and a urinary exosomal proteome analysis for candidate biomarker identification of this disease. A total of 1636 proteins were identified in the whole cell proteome analysis, of which 317 were found to be significantly altered in abundance. Analysis of the urinary exosomal proteome yielded 318 proteins, of which 189 were found to be altered in abundance due to obstruction. Western blot confirmation of a few select proteins provided backing to the quantitative proteome analysis, while gene ontology and KEGG pathway analysis yielded functional information. The results from the quantitative analyses of the urinary exosomes and proximal tubule cells identified candidates for both diagnosis and prognosis of UTO. In addition, activation of a novel pathway was identified, presenting a potential drug target which could be exploited to improve recovery of children following relief of UTO. This thesis therefore contributes useful technological and methodological advancements towards routine proteome analysis, as well as providing candidate biomarker identification for the leading cause of renal functional loss in children.
632

An Empirical Study of Bias in Randomized Controlled Trials and Non-randomized Studies of Surgical Interventions

Sandhu, Lakhbir 19 June 2014 (has links)
Objectives: The aim of this dissertation was to examine bias in randomized controlled trials (RCTs) and non-randomized studies (NRS) in surgery using the literature evaluating laparoscopy and conventional (i.e. open) surgery for the treatment of colon cancer as a case study. The objectives were 1) to develop a conceptual framework for bias in comparative NRS; 2) to compare effect estimates from NRS with those from RCTs at low risk of bias; 3) to explore the impact of NRS-design attributes on estimates of treatment effect. Methods: The methods included a modified framework synthesis, systematic review of the literature, random-effects meta-analyses, and frequentist and Bayesian meta-regression. The Cochrane Risk of Bias Tool was used to classify trials as Strong RCTs (i.e. low risk of bias) or Typical RCTs (i.e. unclear or high risk of bias). Results: A conceptual framework for bias in comparative NRS was developed and it contains 37 individual sources of bias or “items”. These items were organized within 6 overarching “domains”: selection bias, information bias, performance bias, detection bias, attrition bias, and selective reporting bias. Our analyses revealed that NRS were associated with more extreme estimates of benefit for laparoscopy than Strong RCTs when examining subjective outcomes. The odds ratios from NRS were 36% smaller (i.e. demonstrating more benefit for laparoscopy) than those from Strong RCTs for the outcome post-operative complications (Ratio of Odds Ratios, ROR 0.64, [0.42, 0.97], p=0.04). Similar exaggerated benefit was seen among NRS when assessing length of stay, (Difference in Mean Differences, -2.15 days, [-4.08, -0.21], p=0.03). This pattern was not observed with the objective outcomes peri-operative mortality and number of lymph nodes harvested. Analyses adjusted for period effects and between-study case-mix yielded similar findings. Finally, effect estimates in NRS did not consistently vary according to the presence or absence of nine design characteristics identified from the conceptual framework. Conclusions: We have demonstrated that the results of surgical NRS can be significantly biased as compared with those of low risk of bias RCTs when evaluating subjective outcomes. However, none of the nine NRS-design characteristics examined was consistently associated with biased effect estimates.
633

The effect of pharmaceutical excipients on the release of indomethacin from chitosan beads / Riana Havinga

Havinga, Riana January 2006 (has links)
Chitosan has proven through the years as a versatile biomaterial to be used in pharmaceutical applications. Its mucoadhesive properties as well as its ability to manipulate the tight junctions in epithelium membranes have qualified it as an effective drug carrier in controlled drug delivery systems. Microparticles or beads as they are forward called in this study have advantages over conventional drug dosage forms because of a large surface to volume ratio and have the ability to target a specific site for drug release. Indomethacin is an anti-inflammatory drug that causes gastrointestinal side effects in conventional immediate-release dosage forms. The goal is to manipulate the drug delivery vehicle to target the intestines/colon as the site for drug delivery and to minimize this side effect. Thus chitosan beads have been chosen as a drug delivery system for indomethacin in this study. Chitosan beads have been prepared through the ionotropic gelation method using tripolyphophate (TPP) as a cross-linking agent. To prepare the most effective bead to encapsulate indomethacin different formulation and system variables (pH of the TPP solution, the concentration of the TPP solution as well as the indomethacin concentration) have been evaluated according to the following parameters: morphology, drug loading capacity and swelling capability. The ideal pH of the TPP solution was determined at 8.7 and the most effective TPP and indomethacin concentration were 5% w/v and 4% w/v respectively. The chitosan concentration was kept at 3% w/v throughout the study. These concentrations were used to examine the effect of pharmaceutical excipients on the indomethacin release from chitosan beads. The effect of the different excipients namely, ExplotabⒽ(0.25% w/v), Ac-Di-SolⓀ (0.5% w/v) and Vitamin C (0.25% w/v), on the morphology, drug loading capacity, swelling capability as well as the drug release of indomethacin chitosan beads (ICB's) were also studied. The excipients were used in the individually above mentioned concentrations and in combination with each other in the same concentrations. These formulations were used in dissolution studies over a period of 6 hours in PBS pH 7.4 solutions. The indomethacin release rate increased when an excipient was added to the formulation and it dramatically increased when the excipients were added in their various combinations, compared to the formulation that did not contain excipients. / Contents: Chitosan -- Controlled drug delivery -- Indomethacin -- Inotropic gelation -- Tripolyphosphate (TPP) -- Explotab® -- Ac-Di-Sol® -- Vitamin C / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
634

Chitosan beads as a delivery vehicle for the antituberculosis drug pyrazinamide / John Botha Havenga

Havenga, John Botha January 2006 (has links)
Controlled release systems aim at achieving a predictable and reproducible drug release profile over a desired time period. These controlled release formulations offer many advantages over conventional dosage forms. These advantages include: reduced dosing intervals, constant drug levels in the blood, increased patient compliance and decreased adverse effects. Complex controlled release formulations such as those with sustained release properties, often require additional steps during the production phase. The cost and economic impact associated with these complex controlled release dosage formulations often outweigh the short term benefits. Thus the development of an economic method to produce controlled release particles is of great importance especially in third world countries. In controlled release formulations the drug is often equally dispersed throughout a polymer matrix. In the presence of a thermodynamically compatible solvent, swelling occurs and the polymer releases its content to the surrounding medium. The rate of drug release can be controlled by interfering with the amount of swelling and rate of diffusion by manipulating the viscosity of the polymer matrix. Chitosan is an ideal candidate for controlled drug delivery through matrix release systems. It is a biodegradable polymer with absorption-enhancing properties. Cross-linking chitosan with different cross-linking agents allow the preparation of beads. Beads are frequently used in controlled release dosage forms as they are very flexible in dosage form development and show various advantages over single unit dosage forms. Because beads disperse freely in the gastrointestinal tract they maximize drug absorption, reduce fluctuation in peak plasma, and minimize potential side effects without lowering drug bio-availability. Chitosan beads and excipient containing chitosan beads were prepared and investigated as possible controlled release formulations. Pyrazinamide was chosen as the model drug. Chitosan beads and excipient containing chitosan beads were prepared by ionotropic gelation in tripolyphosphate. In this study chitosan/pyrazinamide beads containing pharmaceutical excipients (Ascorbic acid, Explotab and Ac-Di-Sol) were produced. The excipients were added individually and in combinations to the chitosadpyrazinamide dispersion and the beads were characterized on the basis of their morphology, solubility, fiability, drug loading capacity and swelling behaviour, as well as drug release (dissolution properties). The drug loading of the pyrazinarnide loaded chitosan beads, was 52.26 % 0.57%. It was noted that the inclusion of excipients in the beads resulted in an increase in drug loading with the combination of Ascorbic acid and Ac-Di-Sol giving the highest drug loading of 67.09 ± 0.22%. It was expected that the addition of the pharmaceutical excipients would lead to a sustained release of pyrazinamide. Dissolutions studies, however, revealed a burst release in both phosphate buffer solution (PBS) pH 5.60 and 7.40 over the first 15 minutes and the curve reached a plateau after 30 minutes. Thus, apparently the inclusion of the pharmaceutical excipients did not contribute to a sustained release of pyrazinamide over the tested period of six hours. In future studies the dissolution time can possibly be extended to a period of 24 hours. It might be possible for the remaining drug (approximately 40%) in the beads to be released over the extended period. Other polymers can also be investigated to control the release of pyrazinamide. Further studies are, however, necessary to investigate this possibility in the future. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
635

A randomised controlled trial of Absorbatox TM C35 in irritable bowel syndrome: a pilot study / Jean Rial Kloppers.

Kloppers, Jean Rial January 2008 (has links)
Thesis (M. Pharm.)--North-West University, Potchefstroom Campus, 2009.
636

ASSESSING THE RISK FOR AUTOIMMUNE DISORDERS FOLLOWING USE OF THE QUADRIVALENT HUMAN PAPILLOMAVIRUS VACCINE: THE ONTARIO GRADE 8 HPV VACCINE COHORT STUDY

Liu, Yiran 24 April 2014 (has links)
Introduction: In 2007 Ontario implemented a grade 8 quadrivalent human papillomavirus (qHPV) vaccination program targeting the virus that causes cervical cancer. Despite being 6 years post-implementation, few post-licensure studies have assessed the safety of the qHPV vaccine in this adolescent population. Since autoimmune disorders are often targeted for post-marketing surveillance by regulatory agencies, it is important to assess the risk of developing an autoimmune disorder post-qHPV vaccination. Objectives: The objectives of this thesis were to assess the risk for developing an autoimmune disorder following qHPV vaccination, assess for effect modification by the presence of predisposing risk factors, identify the period of highest risk and explore the risk for individual autoimmune disorders. Methods: A population-based retrospective cohort of girls eligible for Ontario’s qHPV vaccination program was identified using population-based databases. The risk of autoimmune disorders following qHPV vaccination was ascertained using the self-controlled case series method. Results: The risk of developing a new autoimmune disorder, adjusted for age, seasonality, concurrent vaccines and infections was 1.28 (95% CI: 0.87 – 1.89), and this association was independent of a history of immune-mediated disorders (p=0.39). The risk was not increased during days 7-24 post-vaccination (adjusted RR = 0.87, 95% CI: 0.43 – 1.74), but appeared to increase thereafter (adjusted RR = 1.36, 95% CI: 0.77 – 2.41 and RR = 1.62, 95% CI 0.94 – 2.78 respectively, for days 25 – 42 and days 43 – 60), although these differences were non-significant. The risk may be increased for certain disorders including Bell’s palsy (RR = 2.30, 95% CI: 0.67 – 7.95), systemic autoimmune rheumatic disorders (RR = 1.84, 95% CI: 0.42 – 8.02), Hashimoto’s disease (RR = 1.39, 95% CI: 0.46 – 4.22), and juvenile rheumatoid arthritis (RR = 1.31, 95% CI: 0.83 – 2.08), although none of these associations were statistically significant. Conclusion: This thesis demonstrated that no statistically significant increased risk for autoimmune disorders following qHPV vaccination was detected. However, there remains some uncertainty about the safety of the qHPV vaccine for a subset of the autoimmune disorders. The results from this analysis need to be pooled with those of other studies to confirm whether these are true safety signals. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2014-04-23 22:30:41.428
637

Performance of Swedish listed family-firms

Rasku, Andreas January 2014 (has links)
This thesis investigates the performance of Swedish listed family-controlled firms using re-turn on assets (ROA) and Tobin’s Q as performance measures. Results show that found-ing-family firms perform 6.1 % better than other firms for ROA. Firm-specific knowledge of the founder-CEO is the main cause of the enhanced performance. The results are not robust to residual testing which suggests caution when drawing conclusions from these re-sults. The main contribution of this thesis is an empirical analysis of family insider repre-sentation and the relation to ROA and Tobin’s Q in a sample consisting entirely of Swedish firms.
638

A randomised controlled trial of Absorbatox TM C35 in irritable bowel syndrome: a pilot study / Jean Rial Kloppers.

Kloppers, Jean Rial January 2008 (has links)
Thesis (M. Pharm.)--North-West University, Potchefstroom Campus, 2009.
639

Prescription Drug Monitoring Programs: A Policy Review and Recommendations for States

Lee, Christine Sh-Teng 30 January 2015 (has links)
OBJECTIVE: To review existing PDMP statutes, and to provide recommendations for good legislative drafting that will create effective statutory components that will enhance the function and increase the use of PDMPs. METHODS: This policy review was conducted from July 2014 to December 2014, using articles dated January 01, 2004 to July 01, 2014. All PubMed searches were artificially limited to peer reviewed articles that were available as “free full text.” To ensure a comprehensive review of the policies, statutes from all fifty states were surveyed using the legal database, Westlaw Next. The search used terms associated with PDMPs. Each statute was reviewed by title and content to determine applicability to the study. The list of statutes compiled from Westlaw Next was compared with existing publications that survey PDMP statutes. The recommendations are based on the investigator’s experience and training in law and public health in consultation with a legislative expert, and supported by peer reviewed articles and legislative drafting guides. RESULTS: There are twelve main topical components that are addressed in existing state PDMP statutes. The policy brief’s primary three recommendations are to implement an advisory committee with an outlined membership, impose a duty for the committee to routinely review database information and to report on the findings, mandate practitioners to consult the database prior to administering controlled substances, and enact a PDMP educational component for practitioners. Appendix A of this policy review (attached) provides a full list of the recommendations for effective legislation on all twelve topical components.
640

Vad avgör om en patient skrivs ut tidigt eller sent vid dagkirurgi med intravenös anestesi som sövningsmetod / If a patient discharge in day surgery with intravenous as anesthesia method what effects an early or late discharge

Ellerström, Zandra January 2015 (has links)
Dagkirurgi verksamheten ökar och det pågår en debatt om vilken anestesiform som är mest lämpad för denna verksamhet. Snabb återhämtning, god kvalitet, kostnadseffektivitet och få biverkningar är målen för att få patienten att kunna gå hem samma dag. En kvantitativ studie med en enkät framkonstruerad för studiens syfte utfördes. Syftet med studien var att undersöka vad om avgör om en patient skrivs ut tidigt eller sent vid dagkirurgi med övningsmetod intravenös anestesi Target Controlled Infusion TCI eller Total Intraveös Anestesi TIVA. 20 stycken patienter på en dagkirurgisk avdelning observerades postoperativt av ansvarig sjuksköterska, som fyllde i frågorna i enkäten. I resultatet framkom det att ålder, smärta postoperativt, en längre operationstid med längre sövningstid och  könsskillnader har betydelse för hur snabb utskrivning sker postoperativt. Vidare i en fullskalig studie bör vara inriktad på patientens hela vistelse på dagkirurgin. / After day surgery patients is discharge within a relatively short time. Some of the benefits of outpatient are quick recovery, increased cost effectiveness and adapted anesthetic techniques with fewer adverse effects. Day Surgery is expanding and there has been a long debate on which anesthesia techniques are most suitable for outpatients. A Quantitative custom made survey for the pilot studies purpose was conducted. The aim was to study what effects the anesthetic method hade on time of discharge of the patients undergoing surgery. The chosen method was Target Controlled Infusion or Total Intravenous Anesthesia. 20 patients were observed by nurses in the postoperative ward of the day surgery unit. The results regarding the differences of the time of discharge shoed that age, post-operative pain, longer surgery time with longer anesthesia and gender differences effected the time of discharge. Further research with a full-scale study ought to focus on the patient’s total stay in day surgery.

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