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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.
41

Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems

Berggren, Martin January 2009 (has links)
Aquatic systems worldwide receive large amounts of organic carbon from terrestrial sources. This ‘allochthonous’ organic carbon (AlloOC) affects critical physical and chemical properties of freshwater ecosystems, with consequences for food web structures and exchange of greenhouse gases with the atmosphere. In the boreal region, loadings of AlloOC are particularly high due to leaching from huge organic deposits in boreal forest, mire and tundra soils. A main process of AlloOC turnover in aquatic systems is its use by heterotrophic bacteria. Applying a bioassay approach, I measured the respiration and growth (production) of bacteria in northern Sweden, in streams and lakes almost totally dominated by AlloOC. The objective was to elucidate how variations in AlloOC source, age, composition and concentration impact on its use by aquatic bacteria, and how AlloOC properties, in turn, are regulated by landscape composition and by hydrology. The bacterial respiration (30-309 µg C L-1 d-1) was roughly proportional to the concentration of AlloOC (7-47 mg C L-1), but not significantly related to AlloOC source or character. Bacterial production (4-94 µg C L-1 d-1), on the other hand, was coupled to the AlloOC character, rather than concentration. A strong coupling to AlloOC character was also found for bacterial growth efficiency (0.06-0.51), i.e. production per unit of assimilated carbon. Bacterial production and growth efficiency increased with rising concentrations of low molecular weight AlloOC (carboxylic acids, free amino acids and simple carbohydrates). While the total AlloOC concentrations generally were the highest in mire-dominated catchments, low molecular weight AlloOC concentrations were much higher in forested catchments, compared to mire-dominated. These patterns were reflected in a strong landscape control of aquatic bacterial metabolism. Moreover, high flow episodes increased the export of organic carbon from forests, in relation to the export from mires, stimulating the bacterial production and growth efficiency in streams with mixed (forest and mire) catchments. The potential of AlloOC to support efficient bacterial growth decreased on time-scales of weeks to months, as the AlloOC was aged in laboratory or lake in situ conditions. To conclude, landscape, hydrology and conditions which determine AlloOC age have large influence on bacterial metabolism in boreal aquatic systems. Considering the role of bacteria in heterotrophic food chains, these factors can have spin-off effects on the structure and function of boreal aquatic ecosystems.
42

Production And Performance Evaluation Of Zif-8 Based Binary And Ternary Mixed Matrix Membranes

Keser, Nilay 01 August 2012 (has links) (PDF)
Mixed matrix membranes (MMMs) have gained importance because they combine the desirable properties of the polymers and the organic/inorganic filler materials and they may have a very big potential. In this study polyethersulfone (PES) was used as polymeric material, and Zeolitic Imidazolate Framework-8 (ZIF-8) was used as porous filler material, and 2-hydroxy 5-methyl aniline(HMA), was used as a third component in membrane formulation. In this study, ZIF-8 crystals were synthesized with varying particle sizes, and a novel recycling methodology was developed to improve the efficiency of ZIF-8 production. ZIF-8 nano-crystals were synthesized by a 1-hour stirring method at room temperature and characterized by X-ray diffractometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and thermal gravimetric analysis (TGA). In order to investigate the effect of ZIF-8 loading on the membrane performance, different types of membranes were prepared with varying amounts of ZIF-8 between 10-60% (w/w). Moreover, ternary mixed matrix membranes were synthesized consisting of different amounts of ZIF-8 between 10-30% (w/w) and HMA 1-10% (w/w). Gas transport properties of the membranes were investigated by single gas permeation experiments of H2, CO2 and CH4 at 3 bar feed pressure. In order to investigate the effect of feed pressure on the gas transport properties of the membranes, single gas experiments were conducted on 3, 6, 8, 10 and 12 bar feed pressures. Moreover, binary gas permeation experiments of CO2/CH4 pair were conducted through selected membranes at 3 bar and 12 bar feed pressures. In addition to gas permeation experiments, the morphology and thermal characteristics of the membranes were characterized by SEM, TGA and differential scanning calorimetry (DSC) analysis. The incorporation of ZIF-8 crystals into continuous PES matrix resulted in high performance gas separation membranes. The permeabilities of all studied gases increased with ZIF-8 loading while the ideal selectivities showed a slight decrease compared to neat PES membrane. Highly reproducible and repeatable results were obtained up to 30 % w/w ZIF-8 loading, while membrane formulation reproducibility was decreased for higher ZIF-8 contents (&gt / 30 w/w %). Addition of HMA improved the gas separation performances of the binary membranes significantly by decreasing permeabilities and increasing ideal selectivities. PES/ZIF-8(%20)/HMA(%7) membrane has the best separation performance for all gases among the ternary membranes. When 7 w/w % HMA was added to PES/ZIF-8(%20) membrane, H2 permeability decreased from 26.3 to 13.7 barrer, while H2/CH4 ideal selectivity increased from 61.8 to 103.7. Increasing feed pressures appreciably increased the separation performances of all membranes. While the H2 permeability is pressure independent, the CO2 and CH4 permeabilities were reduced with increasing feed pressures and the highest selectivity improvement was observed in H2/CH4 pair for all membrane compositions. For instance, when the feed pressure was increased from 3 bar to 12 bar, the percentage improvements in ideal selectivities through PES/ZIF-8(%10)/HMA(%4) membrane were calculated as 26, 69, 113 % for the H2/CO2, CO2/CH4 and H2/CH4 gas pairs / respectively. This results show that working at higher feed pressures will be more advantageous for separation of the studied gas pairs. The ideal selectivities and the separation factors were equal to each other for all membrane compositions both for 3 and 12 bar operating pressures.
43

Liberation of low molecular weight organic acids from sedimentary organic matter and their role on microbial activity

Sauer, Patrick January 2013 (has links)
Low molecular weight organic acids (LMWOAs) are important nutrients for microbes. However, most LMWOAs do not exist freely in the environment but are bound to macromolecular organic matter, e.g. kerogen, lignite and coal. During burial and geological maturation of sedimentary macromolecular organic matter biological and abiological processes promote the liberation of LMWOAs into the surrounding sediment. Through this process, microbes in sedimentary subsurface environments are supplied with essential nutrients. To estimate the feedstock potential of buried macromolecular organic matter to many environments it is important to determine the amount of LMWOAs that are bound to such a matrix. However, high-pressure and high temperature are a key feature of deep subsurface environments, and these physical parameters have a profound influence on chemical reaction kinetics. Therefore it is essential for the estimation of the feedstock potential to generate high-pressure and high temperature for the liberation of LMWOAs to recreate true in-situ conditions. This work presents a newly developed, inexpensive incubation system for biological and geological samples. It allows the application of high-pressure and high temperature as well as a subsampling of the liquid phase without loss of pressure, thereby not disturbing the on-going processes. When simulating the liberation of LMWOAs from sedimentary organic matter, the newly developed incubation system produces more realistic results than other extraction systems like Soxhlet. The extraction products remain in the extraction medium throughout the extraction, influencing the chemical conditions of the extraction medium. Sub-bituminous coal samples from New Zealand as well as lignite samples from Germany were extracted at elevated temperature (90˚C) and pressure (5 MPa). The main LMWOAs released from these low rank coals were formate, acetate and oxalate. Extraction efficiency was increased by two to four times for formate, acetate and oxalate in comparison to existing extraction methods without pressurisation and with demineralised water. This shows the importance of pressure for the simulation of true in-situ conditions and suggests that the amount of bioavailable LMWOAs is higher than previously thought. With the increase in carbon capture and storage (CCS) and the enhanced recovery of oil and gas (EOR/EGR), more and more CO2 becomes injected into the underground. However, the effects of elevated concentrations of carbon dioxide on sedimentary organic matter are rarely investigated. As the incuabtion system allows the manipulation of the composition and partial pressure of dissolved gasses, the effect of highly gas-enriched (CO2, CO2/SO2, CO2/NO2; to simulate flue gas conditions) waters on the extraction yield of LMWOAs from macromolecular organic matter was evaluated. For sub-bituminous coal the concentrations of all LMWAOs decreased upon the addition of gas, irrespective of its composition, whereas for lignite formate always and acetate mostly increased, while oxalate decreased. This suggests an positive effect on the nutrient supply for the subsurface microbiota of lignite layers, as formate and acetate are the most common LMWOAs used for microbial metabolism. In terrestrial mud volcanoes (TMVs), sedimentary material is rapidly ascending from great depth to the surface. Therefore LMWOAs that were produced from buried macromolecular organic matter at depth are also brought up to the surface, and fuel heterotrophic microbial ecosystems at the surface. TMVs represent geochemically and microbiologically diverse habitats, which are supplied with organic substrates and electron acceptors from deep-seated hydrocarbon-generating systems and intersected shallow aquifers, respectively. The main electron donor in TMVs in Azerbaijan is sulphate, and microbial sulphate reduction leads to the production of a wide range of reduced sulphur species that are key players in several biological processes. In our study we estimated the effect of LMWOAs on the sulphur metabolising activity of microorganims in TMVs from Azerbaijan. The addition of a mixture of volatile fatty acids containing acetate and other LMWOAs showed significant positive response to the sulphate reduction rate (SRR) of samples of several mud volcanoes. Further investigations on the temperature dependency of the SRR and the characterisation of thermophilic sulphate-reducing bacteria (SRB) showed a connection between the deep hot subsurface and the surface. / Niedermolekulare organische Säuren (nachfolgend als LMWOAs - low molecular weight organic acids - bezeichnet) stellen wichtige mikrobielle Substrate dar. Jedoch liegen die meisten LMWOAs nicht in freier, bioverfügbarer Form vor, sondern sind vielmehr an hochmolekulare organische Substanzen gebunden, z.B. Kerogen, Lignit und Kohle. Während der geologischen Verbringung in tiefe Erdschichten und der geologischen Reifung von sedimentären hochmolekularen organischen Substanzen, führen biologische und abiologische Prozesse zu einer Freisetzung von LMWOAs in die umgebenden Sedimente. Durch diesen Prozess werden Mikroorganismen in unterirdischen sedimentären Ökosystemen mit essentiellen Nährstoffen versorgt. Um das Nährstoffpotential tief liegender hochmolekularer organischer Substanzen für diverse Ökosystemen abschätzen zu können, ist es notwendig, die Menge an LMWOAs, die an solch eine hochmolekulare Matrix gebunden ist, zu bestimmen. Dabei stellen hoher Druck sowie hohe Temperatur entscheidende Faktoren in tiefen unterirdischen Ökosystemen dar, welche einen signifikanten Einfluss auf chemische Reaktionen haben. Daher ist es für die Abschätzung des Nährstoffpotentials entscheidend, hohen Druck und hohe Temperatur bei der Freisetzung von LMWOAs zu erzeugen, um wahre in situ Bedingungen zu schaffen. In der vorliegenden Arbeit wird ein neu entwickeltes, preiswertes Inkubationssystem für biologische und geologische Proben präsentiert. Es erlaubt die Verwendung von hohem Druck als auch hoher Temperatur sowie eine Unterprobennahme der flüssigen Phase ohne Druckverlust, um den fortlaufende Prozess nicht zu unterbrechen. Bei der Simulierung der Freisetzung von LMWOAs aus sedimentären organischen Substanzen erhält man mit dem neu entwickelten Inkubationssystem realistischere Resultate als mit anderen Extraktionssystemen, wie z.B. eine Soxhlet-Apparatur. Die Extraktionsprodukte verbleiben während der Extraktion im Extraktionsmedium, wodurch die chemischen Bedingungen verändert werden. Kohleproben aus Neuseeland sowie aus Deutschland wurden mittels erhöhter Temperatur (90°C) und Druck (5 MPa) extrahiert. Die wichtigsten LMWOAs, die aus diesen Kohlen freigesetzt wurden, waren Formiat, Acetat und Oxalat. Die Extraktionseffizienz für diese LMWOAs konnte im Vergleich zu existierenden Extraktionsmethoden ohne Druck um den Faktor 2 bis 4 gesteigert werden. Dies zeigt die Bedeutung von Druck bei der Simulation von in situ Bedingungen und legt nahe, dass die Menge an bioverfügbaren LMWOAs größer ist als bisher angenommen. Durch die Zunahme der CO2-Speicherung im Untergrund (carbon capture and storage, CCS) sowie der erweiterten Förderung von Öl und Gas (enhanced recovery of oil and gas, EOR/EGR) wird immer mehr CO2 in den Untergrund gepresst. Jedoch sind die Auswirkungen von erhöhten CO2-Konzentrationen auf sedimentäre organische Materie noch unerforscht. Da mit dem Inkubationssystem die Veränderung der Zusammensetzung und des Partialdruckes von gelösten Gasen möglich ist, wurde der Effekt von hoch mit Gasen (CO2, CO2/SO2, CO2/NO2; um Kraftwerksabgase zu simulieren) angereicherten Wässern auf die Extraktionsausbeute von LMWOAs untersucht. Bei der subbituminösen Kohle zeigte sich eine Abnahme aller LMWOAs-Konzentrationen durch die Lösung von Gas im Extraktionsmedium, wobei die Art des Gases keine Rolle spielte. Bei Lignit konnte hingegen festgestellt werden, dass die Extraktionsausbeute an Formiat immer und an Acetat meistens erhöht wurde, während sie sich bei Oxalat verringerte. Dies deutet auf einen positiven Effekt für die Nährstoffversorgung von Mikroorganismen um Lignit-Lagerstätten an, da Formiat und Acetat die am häufigsten verwendeten LMWOAs im mikrobiellen Stoffwechsel darstellen. In terrestrischen Schlammvulkanen (terrestrial mud volcanoes, TMVs) steigt sedimentäres Material aus großen Tiefen an die Erdoberfläche. Somit werden auch LMWOAs, welche aus hochmolekularen organischen Substanzen freigesetzt werden, an die Oberfläche verbracht, und ermöglichen dort heterotrophe Ökosysteme. TMVs stellen dabei geochemisch und mikrobiell unterschiedliche Habitate dar, welche mit organischen Substraten und Elektronenakzeptoren aus tief liegenden, Kohlenwasserstoffe erzeugenden Systemen versorgt werden. In TMVs in Aserbaidschan stellt Sulfat den Hauptelektronenakzeptor dar, wobei mikrobielle Sulfatreduktion zu einer Vielzahl an reduzierten Schwefelspezies führt. In der vorliegenden Arbeit wurde der Effekt von LMWOAs auf die Aktivität von Mikroorganismen bei der Umsetzung von Schwefel in TMVs in Aserbaidschan untersucht. Die Zugabe einer Mischung verschiedener kurzkettiger Fettsäuren zu Schlammproben verschiedener TMVs erzeugte eine signifikant positive Reaktion in Bezug auf die Sulfat-Reduktionsraten. Weiterführende Untersuchungen zur Temperaturabhängigkeit der Sulfat-Reduktionsraten und die Charakterisierung thermophiler, Sulfat-Reduzierender Bakterien zeigte eine Verbindung zwischen der tiefen, heißen Biosphäre und der Erdoberfläche auf.
44

Dose individualisation of enoxaparin

Michael Barras Unknown Date (has links)
Abstract The global aims of this thesis were: to evaluate if an individualised dose strategy for enoxaparin, based on lean body weight and renal function, resulted in a reduction in the prevalence of bleeding and bruising events when compared to conventional dosing; to further understand the dose-exposure-response relationship for enoxaparin using population pharmacokinetic-pharmacodynamic (PKPD) modelling. This thesis comprises seven chapters: an introduction to the current knowledge and literature pertaining to low-molecular-weight heparins (LMWHs), in particular enoxaparin; five research chapters; and a discussion. Each of the five research chapters consists of a manuscript that has been published in, accepted or submitted for peer review in a scientific journal. Preceding each chapter is a synopsis of the important features of the publication. Supplementary information that supports the findings of the publication, but could not be included in the publication, is provided at the end of the chapter. Appendices relevant to each chapter are located at the end of the thesis. Chapter one is the introduction to this thesis. It commences with an overview of the LMWHs, their mechanism of action, customary uses, licensed doses and adverse effects. There is a brief introduction to renal function and body composition; physiological factors that influence the disposition of LMWHs. As much of this thesis is centred on defining the dose-exposure-response relationship for enoxaparin, there is a critique of the existing literature relevant to each segment of this relationship, namely: dose-exposure, exposure-response and dose-response. To conclude this chapter there is a review of pharmacostatistical models and population modelling, followed by an appraisal of population PK and PKPD models that have previously been developed for enoxaparin, including the two key publications that are critical to this thesis. These two papers were the first to fully describe the dose-exposure relationship for enoxaparin in subjects with renal impairment and obesity. It is from these studies that the individualised dosing strategy, explored throughout this thesis, was developed. The specific aims of the five research chapters are then stated. Chapter two describes a confirmatory, randomised controlled trial (RCT) to compare an individualised dose of enoxaparin to conventional, label based dosing. The RCT was conducted at a major tertiary teaching hospital over an 18 month period. The primary endpoint was the prevalence of overt bleeding events and the secondary endpoint a combination of bleeding or major bruising events. A time-to-bleeding event analysis (Kaplan-Meier) was used and markers of effectiveness such as mortality and readmission were assessed out to 30 days post recruitment. Bleeding and bruising data, along with anti-Xa (aXa)-concentrations were collected for use in additional research described in chapters four and five. Chapter three details the evolution, progression and contemporary knowledge of drug dosing based on body composition and focuses on dosing in obese subjects with cardiovascular disease. The concept of dose-individualisation is explored in this chapter with reference to the methods used to normalise drug exposure across the spectrum of body compositions. Subsequently, there is a review of body size descriptors, such as lean body weight, that are used to scale dosing in the obese. Enoxaparin is used as a motivating example, with reference to data presented in Chapter two of this thesis. There is also a discussion about the type of research designs that are required to maximise information about PK parameters. This chapter was published within a book chapter which was intended for clinical practitioners in the discipline of cardiology. Chapter four is focused on the development and evaluation of population PK and PKPD models to describe the time-course of effects for enoxaparin. A population PK model linked to a proportional-odds model was used to describe the severity of an adverse event as a function of exposure and demographic variables. The final model was used to explore the likely occurrence of bleeding and bruising events in patients with obesity and / or renal impairment dosed using either the individualised or conventional dose strategies from Chapter two. Chapter five describes a study that was undertaken to evaluate the ability of the individualised dosing strategy to achieve and maintain aXa-concentrations within the therapeutic range (500 to 1000 IU L-1), by comparison to conventional dosing. As the confirmatory study focused on the prevalence of adverse events there was no assessment of the therapeutic capability of the dose strategies however, as aXa-concentrations were collected using a sparse design during the confirmatory study, the two dose strategies could not be compared using observed data. Therefore, the population PK model developed in Chapter four was used to predict individual subject concentration-time profiles to 120 hours of enoxaparin therapy. The time spent in the therapeutic, supra-therapeutic and sub-therapeutic ranges was computed for each subject and the dosing strategies statistically compared. This study also allowed the evaluation of the results from Chapter two from a dose-exposure perspective. Chapter six of this thesis describes a survey. The aim of this survey was to gain an understanding of how dosing strategies of enoxaparin vary in four countries, investigate if clinicians are prescribing according to the Product label, and determine the methods used to dose-individualise enoxaparin. In doing so, individual hospitals in the international community will be able to compare, critique or benchmark their own strategies to peer hospitals, as well as the current literature. The publication arising from this survey would assist in the dissemination of knowledge gained from the earlier chapters of this thesis. Chapter seven is the final discussion and conclusions of the thesis along with prospects for future research.
45

Efeito da heparina de baixo peso molecular na perda óssea alveolar em ratos Wistar machos : análises morfométrica e histológica / Effects of low molecular weight heparin on alveolar bone loss in wistar rats: Morphometricand histological analyses

Rivera Oballe, Harry Juan January 2017 (has links)
O objetivo da presente tese foi avaliar os efeitos da heparina de baixo peso molecular (HBPM) na perda óssea alveolar em ratos Wistar. Para a melhor compreensão e entendimento dos efeitos da HBPM se elaborou um único artigo com 40 ratos machos da linhagem Wistar de 60 dias de nascidos, os quais foram dívidos em 4 grupos experimentais previamente randomizados: Grupo Controle (C), Grupos Doença Periodontal (DP), Grupo Heparina (Hp) e Grupo Heparina+Doença Periodontal (Hp+DP) com um período experimental de 60 dias. Um animal foi perdido no período de aclimação, dois animais foram perdidos na primeira de três coletas sanguíneas pré-programadas e um rato foi perdido na colocação da ligadura. Os resultados observados foram analisados são perda óssea alveolar induzida onde houve diferença significava entre os grupos (C) e (DP), entre o grupo (C) e (Hp+DP), entre o grupo (DP) e (Hp) e o grupo (Hp) e (Hp+DP). Foi avaliado perda óssea alveolar não induzida onde não existiu diferença entre os grupos. Foi avaliado o peso do início ao final do período experimental. Foram avaliados o consumo de ração e agua onde não houve diferença significativa entre os grupos. Foram avaliados o número de megacariócitos nos fémures, onde também não existiram diferenças estatísticas. Foram avaliados números de adipócitos no timo, não havendo diferença significativa entre os grupos. Foram avaliados as plaquetas e desvio padrão onde não existiu diferença significativa entre os grupos. Foram avaliados os leucócitos e desvio padrão onde não houve diferença significativa entre os grupos. Posteriormente foi avaliado a porcentagem de linfócitos onde se achou diferença estatisticamente significativa na segunda coleta sanguínea entre o grupo (C) e grupo (Hp+DP) e grupo (Hp) e grupo (Hp+DP). Foi assim que as conclusões deste trabalho foram que o presente estudo mostrou que a HBPM não foi capaz de produzir perda óssea alveolar nos ratos Wistar, mas foi capaz de aumentar a quantidade de leucócitos e linfócitos, indicando a presença de um processo inflamatório. / In order to better understand and understand the effects of (LMWH), a single article was elaborated with 40 male rats of the 60 day old Wistar line, which were divided into four previously randomized experimental groups: Control Group (C), Groups Periodontal Disease (PD), Heparin Group (Hp) and Heparin Group + Periodontal Disease (Hp + PD) with an experimental period of 60 days. One animal was lost in the acclimation period, two animals were lost in the first of three preprogrammed blood collections and one mouse was lost in the ligation placement. The observed results were analyzed for induced alveolar bone loss where there was significant difference between groups (C) and (PD), between group (C) and (Hp + PD), between (PD) and (Hp) group and Group (Hp) and (Hp + PD). Uninduced alveolar bone loss was assessed where there was no difference between the groups. The weight of the onset at the end of the experimental period was evaluated. The ration and water consumption were evaluated where there was no significant difference between the groups. The number of megakaryocytes in the femurs was evaluated, in which there were also no statistical differences. Adipocyte numbers were evaluated in the thymus, with no significant difference between the groups. Platelets and standard deviation were evaluated where there was no significant difference between the groups. Leukocytes and standard deviation were evaluated where there was no significant difference between the groups. Later, the percentage of lymphocytes where a statistically significant difference was found in the second blood collection between group (C) and group (Hp + PD) and group (Hp) and group (Hp + PD) was evaluated. Thus the conclusions of this study were that the present study showed that LMWH was not able to produce alveolar bone loss in Wistar rats, but was able to increase the amount of leukocytes and lymphocytes, indicating the presence of a process inflammatory.
46

Efeito da heparina de baixo peso molecular na perda óssea alveolar em ratos Wistar machos : análises morfométrica e histológica / Effects of low molecular weight heparin on alveolar bone loss in wistar rats: Morphometricand histological analyses

Rivera Oballe, Harry Juan January 2017 (has links)
O objetivo da presente tese foi avaliar os efeitos da heparina de baixo peso molecular (HBPM) na perda óssea alveolar em ratos Wistar. Para a melhor compreensão e entendimento dos efeitos da HBPM se elaborou um único artigo com 40 ratos machos da linhagem Wistar de 60 dias de nascidos, os quais foram dívidos em 4 grupos experimentais previamente randomizados: Grupo Controle (C), Grupos Doença Periodontal (DP), Grupo Heparina (Hp) e Grupo Heparina+Doença Periodontal (Hp+DP) com um período experimental de 60 dias. Um animal foi perdido no período de aclimação, dois animais foram perdidos na primeira de três coletas sanguíneas pré-programadas e um rato foi perdido na colocação da ligadura. Os resultados observados foram analisados são perda óssea alveolar induzida onde houve diferença significava entre os grupos (C) e (DP), entre o grupo (C) e (Hp+DP), entre o grupo (DP) e (Hp) e o grupo (Hp) e (Hp+DP). Foi avaliado perda óssea alveolar não induzida onde não existiu diferença entre os grupos. Foi avaliado o peso do início ao final do período experimental. Foram avaliados o consumo de ração e agua onde não houve diferença significativa entre os grupos. Foram avaliados o número de megacariócitos nos fémures, onde também não existiram diferenças estatísticas. Foram avaliados números de adipócitos no timo, não havendo diferença significativa entre os grupos. Foram avaliados as plaquetas e desvio padrão onde não existiu diferença significativa entre os grupos. Foram avaliados os leucócitos e desvio padrão onde não houve diferença significativa entre os grupos. Posteriormente foi avaliado a porcentagem de linfócitos onde se achou diferença estatisticamente significativa na segunda coleta sanguínea entre o grupo (C) e grupo (Hp+DP) e grupo (Hp) e grupo (Hp+DP). Foi assim que as conclusões deste trabalho foram que o presente estudo mostrou que a HBPM não foi capaz de produzir perda óssea alveolar nos ratos Wistar, mas foi capaz de aumentar a quantidade de leucócitos e linfócitos, indicando a presença de um processo inflamatório. / In order to better understand and understand the effects of (LMWH), a single article was elaborated with 40 male rats of the 60 day old Wistar line, which were divided into four previously randomized experimental groups: Control Group (C), Groups Periodontal Disease (PD), Heparin Group (Hp) and Heparin Group + Periodontal Disease (Hp + PD) with an experimental period of 60 days. One animal was lost in the acclimation period, two animals were lost in the first of three preprogrammed blood collections and one mouse was lost in the ligation placement. The observed results were analyzed for induced alveolar bone loss where there was significant difference between groups (C) and (PD), between group (C) and (Hp + PD), between (PD) and (Hp) group and Group (Hp) and (Hp + PD). Uninduced alveolar bone loss was assessed where there was no difference between the groups. The weight of the onset at the end of the experimental period was evaluated. The ration and water consumption were evaluated where there was no significant difference between the groups. The number of megakaryocytes in the femurs was evaluated, in which there were also no statistical differences. Adipocyte numbers were evaluated in the thymus, with no significant difference between the groups. Platelets and standard deviation were evaluated where there was no significant difference between the groups. Leukocytes and standard deviation were evaluated where there was no significant difference between the groups. Later, the percentage of lymphocytes where a statistically significant difference was found in the second blood collection between group (C) and group (Hp + PD) and group (Hp) and group (Hp + PD) was evaluated. Thus the conclusions of this study were that the present study showed that LMWH was not able to produce alveolar bone loss in Wistar rats, but was able to increase the amount of leukocytes and lymphocytes, indicating the presence of a process inflammatory.
47

Trombofilie a trombotické komplikace u nemocných se závažnou sepsí. / Thrombophilia and thrombotic complications in severe septic patients

Zenáhlíková, Zuzana January 2013 (has links)
Introduction: Thrombotic events are among the most serious complications of sepsis and also the most frequent causes of morbidity and mortality in patients with sepsis. Currently, the administration of low molecular weight heparins (LMWH) is recommended in patients with severe sepsis for prophylaxis of these complications. However, this prophylaxis often fails. Objectives of the study: One of the objectives of our study was to examine changes in haemostasis in relation to the inflammatory response during 15 days of severe sepsis. The next objective was to determine whether a prophylactic inhibition of F Xa in the range from 0.2 to 0.4 IU/mL is achieved in these patients, if they receive the recommended prophylaxis with LMWH. We also recorded the dynamics of changes in the F Xa inhibition during the entire study period. Moreover, we tried to identify the factors that may affect the antithrombotic efficacy of the subcutaneously administered enoxaparin. Patient population and methods: A total of 35 ICU patients meeting the criteria of severe sepsis were enrolled in the study. Only 16 of these patients could be followed throughout the entire 15-day period. Patients were treated according to the current guidelines, including LMWH prophylaxis; enoxaparin (40 mg sc per day) was used in this study....
48

Estudo proteômico de vermes adultos machos e fêmeas de Schistosoma mansoni / Proteomic studies of male and female Schistosoma mansoni adult worms

Camila Macêdo Ribeiro 11 April 2011 (has links)
A esquistossomose é uma doença tropical negligenciada que atinge cerca de 200 milhões de pessoas em todo o mundo, abrangindo a América, a África, as Antilhas, o Oriente Médio e Próximo, além do Sudeste Asiático. A espécie encontrada no Brasil é a Schistosoma mansoni, onde se tem como tratamento típico a administração do Praziquantel ou da Oxamniquina. No entanto, sua característica de infecção se associa a saneamento básico precário e baixos padrões sócio-econômicos, de maneira que a reinfecção de doentes apresenta altas taxas de ocorrência, o que motiva a busca por fármacos ou vacinas antihelmíticas que superem esta dificuldade. Neste trabalho são utilizadas técnicas proteômicas para a identificação de proteínas que estejam potencialmente envolvidas na diferenciação entre os sexos, na interação entre parasitas de diferentes sexos ou com o hospedeiro. São estudadas preparações de amostras de sincício e vermes inteiros adultos machos e fêmeas por eletroforese bidimensional e frações de baixo peso molecular de sincício de vermes adultos machos e fêmeas por gel-LC. A expressão diferencial de proteínas de sincício investigada por gel-LC foi avaliada por análise estatítica, sendo detectadas 5 proteínas mais abundantes em machos e 2 em fêmeas, além de 6 proteínas identificadas somente em machos e 21 somente em fêmeas. Estas informações de expressão diferencial possibilitam a investigação dos recursos de sobrevivência e reprodução desenvolvidos evolutivamente por estes parasitas. / Schistosomiasis is a neglected tropical disease that affects approximately 200 million people around the world, occurring in America, Africa, the Antilles, Middle East and Near East, besides Southeast Asia. The species found in Brazil is Schistosoma mansoni, the typical treatment being administration of either Praziquantel or Oxamniquine. Although, the infection characteristics of this disease is associated with poor sanitation and hardened socio-economic conditions, resulting in high reinfection rates, which motivates the search for antihelmintic drugs and vaccines that overcome this situation. In this study proteomics techniques are used in the search of proteins potencially involved in the differentiation of individuals of both sexes, in the interactions between them and between the worms and the host. Samples of worm syncytium and adult whole worms of both male and female are studied by two-dimentional electrophoresis, while low molecular weight syncytium proteins from male and female adult worms were investigated by gel-LC. The differential protein expression in the syncytium investigated by gel-LC was analyzed statistically, being detected 5 proteins most abundant in males, and 2 in females, while 6 were identified solely on males and 21 on females. The information concerning protein differential expression allows the investigation of survival strategies developed evolutionarily by these parasites.
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Oral anticoagulation and stroke risk

Sjögren, Vilhelm January 2017 (has links)
Background: The risk of ischaemic stroke in patients with atrial fibrillation (AF) and mechanical heart valve (MHV) prostheses can be reduced by oral anticoagulation (OAC), which increases the risk of serious bleeding. The aims of this thesis were [1] to find out how effective and safe warfarin is where treatment quality is high, i.e. Sweden, with proportion of time that patients spend within the therapeutic range (TTR) &gt;70%, [2] whether there is evidence for administering low-molecular-weight heparin (LMWH) during temporary interruptions of OAC (bridging therapy), and whether non-vitamin K-dependent oral anticoagulants (NOACs) as a group, [3] or individually, [4] are more effective and safer than warfarin when used for stroke prevention in patients with AF. Materials and methods: All four studies were retrospective, based on the Swedish anticoagulation register Auricula, and done with merging of data from some or all of the National Patient Register, the Prescribed Drug Register, the Swedish Stroke Register (Riksstroke), and the Cause of Death Register. In studies 2–4, propensity score matching was performed to obtain treatment groups with similar risk profiles. Outcomes were defined as haemorrhages or thromboses requiring specialist care, or death. Haemorrhages were intracranial, gastrointestinal, or other. Thromboses were ischaemic stroke, systemic embolism, myocardial infarction, or venous thromboembolism (VTE). Study 1 described all patients on warfarin during 2006–2011, which was before the introduction of NOACs. Study 2 was a cohort study of all patients who had a planned interruption of warfarin during the same period. Study 3 included all 49,011 patients starting OAC for stroke prevention due to AF between 1 July 2011 and 31 December 2014, and study 4 all 64,382 patients with the same indication between 1 January 2013 and 31 December 2015. Results: Study 1 showed that for the 77,423 patients on warfarin with 217,804 treatment years, TTR was 77.4% for patients with AF, 74.5% with MHV, and 75.9% with VTE. Annual rates of intracranial bleeding were 0.38%, 0.51%, and 0.30%. In study 2, with 14,556 warfarin interruptions, the 30-day risk of a bleeding requiring specialist care was 0.64% for LMWH treated and 0.46% for controls. For patients with VTE as indication for OAC, bleeding rate with LMWH was significantly higher at 0.85% vs. 0.16% (hazard ratio 5.24, 95% confidence interval 1.39–19.77), but with no difference for patients with MHV or AF. The incidence of ischaemic complications was higher in the LMWH bridging group overall and for patients with MHV and AF, but not for patients with VTE. In study 3, for the 12,694 patients starting NOAC (10,392 treatment years) or matched warfarin patients (9,835 treatment years, TTR 70%) due to AF, annual incidence of ischaemic stroke and systemic embolism did not differ between the groups (1.35% vs. 1.58%), but risks of major bleedings and intracranial bleedings were significantly lower: 2.76% vs. 3.61% and 0.40% vs. 0.69%. In study 4, patients on individual NOACs (6,574 dabigatran, 8,323 rivaroxaban, 12,311 apixaban) were compared to 37,174 patients starting warfarin (in total 81,176 treatment years). No NOAC showed any difference in risk of ischaemic stroke or systemic embolism, but there were fewer intracranial bleedings, serious bleedings overall, and deaths for dabigatran and apixaban compared to warfarin. For patients starting rivaroxaban the risk of gastrointestinal bleeding was higher than for matched warfarin counterparts, with no significant differences in other bleeding risks, or mortality. Conclusions: Swedish warfarin treatment shows TTR levels that are high by international standards, correlating to low incidences of ischaemic and haemorrhagic events. LMWH bridging has not been proven beneficial, even for patients with MHV, meaning that bridging in general cannot be recommended. NOACs as a group were safer than high-quality warfarin treatment. Efficacy did not differ, even when comparing individual NOACs to warfarin, but there were fewer bleedings on dabigatran and apixaban. Although not more efficient than warfarin with a high TTR, NOACs should be the recommended first choice for OAC in AF, on the merit of lower bleeding risks. / <p>Finansiär: Forskning och Utveckling, Region Västernorrland</p>
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Anticoagulation Review: A Primer for the Home Health Care Provider

Stewart, David W., Gentry, Chad, Freshour, Jessica 01 April 2012 (has links)
Anticoagulants, also known as antithrombotics, are among the most commonly prescribed medications in the United States. Understanding how these medications work, the propensity for interactions with other drugs, dietary factors, and disease states is important for clinicians assessing and providing care to patients in all environments. In this review, we seek to provide essential information for the home health care provider for evaluating patients receiving anticoagulants commonly prescribed in the home health care setting. The low-molecular-weight heparins and vitamin K antagonists are the most commonly used agents for outpatient anticoagulation. New agents, such as the direct factor Xa inhibitors and direct thrombin inhibitors have recently been approved with additional new agents in the approval process and development pipeline. We seek to review the most pertinent information for each of these classes of medications providing information on pharmacology, interactions with other drugs, diet, and diseases and important clinical information.

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