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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

Einflussgrößen der Nephrotoxizität eines Radiotracers am Beispiel der Radioimmuntherapie mit 188Re-anti-CD66

Oehme, Liane 02 December 2008 (has links)
Die Nephrotoxizität ist die wichtigste Nebenwirkung bei Applikation von Radioimmunkonjugaten zur Konditionierung des Knochenmarks bei der Leukämiebehandlung. Die Auswirkungen der Unsicherheiten bei der Dosisbestimmung der Niere, insbesondere durch individuelle Nierenmasse und regionale Aktivitätsunterschiede, wurden untersucht. Die biologische Strahlenwirkung wurde als Biologisch Effektive Dosis unter Berücksichtigung des Zeitverlaufs der Dosisapplikation quantifiziert. Berechnungen wurden neben 188Rhenium auch für andere therapierelevante Radionuklide durchgeführt.
32

Análisis de la influencia in vitro de bajas dosis de radiación producidas por 222Rn sobre proliferación celular, apoptosis y respuesta a agentes citotóxicos

Sainz Fernández, Carlos 25 October 2002 (has links)
Los efectos biológicos producidos por dosis bajas de radiación continúan siendo objeto de controversia. Cada cierto tiempo aparecen nuevos estudios a escala molecular y celular que arrojan luz sobre los mecanismos moleculares básicos que subyacen en las respuestas de los sistemas vivos a las radiaciones ionizantes. En esta tesis se muestran tanto la metodología empleada como los resultados obtenidos tras la irradiación in vitro de diferentes líneas celulares tumorales y no tumorales. Para irradiar los cultivos con dosis bajas (del orden del mGy) de radiación alfa se ha puesto a punto un dispositivo para disolver el gas radiactivo 222Rn en el medio de cultivo celular.Los resultados más interesantes han sido los obtenidos tras la irradiación de la línea MCF-7 de cáncer de mama humano metastásico. Junto con la observación de cambios en el crecimiento (no relacionadas linealmente con la dosis), los análisis genéticos revelaron modificaciones en la expresión de genes de la familia Bcl-2, reguladores de la muerte celular por apoptosis. En concreto, el gen bcl-xS (relacionado con quimiorresistencia en esta línea celular) sólo se expresó en los cultivos irradiados. Tras este resultado se analizó la influencia de la radiación sobre la sensibilidad de las MCF-7 a los fármacos Taxol y VP-16, observándose que los cultivos previamente irradiados respondían mejor al tratamiento con ambos quimioterápicos. / Biological effects due to low doses of radiation still remain as a controversial issue. Every certain time new studies on a cellular and molecular basis give out light on the basic mechanisms underlying the response of living systems to ionising radiation. In this thesis the methodology and results obtained after in vitro irradiation of tumour and normal cell lines are described. In order to expose cells to low doses of alpha particles, a new device for dissolving radioactive gas 222Rn in the culture medium was set up.The most remarkable results are those obtained after the irradiation of human breast metastasic cells of the line MCF 7. Together with influences on the growth rate (non linearly related with the dose of radiation), also genetic changes were observed in the expression of some Bcl 2 gene family members related with apoptotic cell death. In short, bcl xs (related with multidrug resistance phenomena in this cellular line) was only expressed in irradiated cell cultures. After this result, the influence of alpha irradiation on the sensibility of MCF 7 to the chemotherapeutic drugs Taxol and VP 16 was analysed, obtaining that those cell cultures previously irradiated showed an improved response to the action of the drugs.
33

Comparative risk assessment of carcinogens in alcoholic beverages using the margin of exposure approach

Lachenmeier, Dirk W., Przybylski, Maria C., Rehm, Jürgen 06 August 2012 (has links) (PDF)
Alcoholic beverages have been classified as carcinogenic to humans. As alcoholic beverages are multicomponent mixtures containing several carcinogenic compounds, a quantitative approach is necessary to compare the risks. Fifteen known and suspected human carcinogens (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, lead, 4-methylimidazole, N-nitrosodimethylamine, ochratoxin A and safrole) occurring in alcoholic beverages were identified based on monograph reviews by the International Agency for Research on Cancer. The margin of exposure (MOE) approach was used for comparative risk assessment. MOE compares a toxicological threshold with the exposure. MOEs above 10,000 are judged as low priority for risk management action. MOEs were calculated for different drinking scenarios (low risk and heavy drinking) and different levels of contamination for four beverage groups (beer, wine, spirits and unrecorded alcohol). The lowest MOEs were found for ethanol (3.1 for low risk and 0.8 for heavy drinking). Inorganic lead and arsenic have average MOEs between 10 and 300, followed by acetaldehyde, cadmium and ethyl carbamate between 1,000 and 10,000. All other compounds had average MOEs above 10,000 independent of beverage type. Ethanol was identified as the most important carcinogen in alcoholic beverages, with clear dose response. Some other compounds (lead, arsenic, ethyl carbamate, acetaldehyde) may pose risks below thresholds normally tolerated for food contaminants, but from a cost-effectiveness point of view, the focus should be on reducing alcohol consumption in general rather than on mitigative measures for some contaminants that contribute only to a limited extent (if at all) to the total health risk.
34

Veränderungen von Indikatoren der “Lebensqualität” nach Hochdosis-Chemotherapie / Changes of concise Quality of Life indices after high-dose chemotherapy

Kamm, Margret 09 June 2004 (has links)
No description available.
35

Evaluación de métodos de Monte Carlo de equipos de mamografía digital del programa de cribado de la Comunidad Valenciana

Ramos Pascual, Miguel 06 May 2008 (has links)
El cribado mamográfico o screening consiste en la exposición sistemática y organizada de mujeres asintomáticas a mamografía, con el fin de detectar precozmente cualquier enfermedad en sus primeras etapas. Sin embargo, la exposición de la mama a la radiación ionizante de un equipo mamográfico supone un riesgo para la salud de las mujeres estudiadas que es necesario estimar y controlar. Los métodos de Monte Carlo se utilizan en el transporte de radiación para estimar magnitudes dosimétricas, como la dosis absorbida, que está relacionada con el riesgo de exposición. Se ha modelado un equipo de mamografía mediante el código de Monte Carlo MCNP5 para la estimación de la dosis media glandular absorbida en la mama a través de medidas físicas del kerma en aire en la superficie de entrada (KASE) durante controles de calidad. Se han utilizado diferentes registros dosimétricos o tallies, como las F2, F4 y F5, aplicando diferentes técnicas de reducción de varianza (TRV). A partir de las dosis medias calculadas, se estimó el riesgo radiológico en el programa de cribado mamográfico de la Comunidad Valenciana mediante un modelo de riesgo multiplicativo derivado de procesos de Markov, considerando diferentes estudios de control: Life Span Study, los estudios de fluoroscopia de Canadá y Massachussets y los tratamientos de enfermedades benignas de mama en Suecia, entre otros. El estudio se aplicó a diferentes equipos de mamografía digital (CR y DR) implantados en el programa de cribado, para la evaluación de calidad de las diferentes tecnologías en lo que respecta a la dosis glandular absorbida. El detrimento radiológico medio ha sido inferior a 9 10-5 cánceres de mama inducidos en mujeres-año, entre todos los estudios de incidencia y mortalidad, e inferior a 6 10-5 cánceres mortales, mientras que para el caso de mamografía digital, la incidencia es inferior a 1.3 10-4 y la mortalidad a 8 10-5. Los riesgos radiológicos son mayores en las muestras poblacionales de equipos digitales po / Ramos Pascual, M. (2006). Evaluación de métodos de Monte Carlo de equipos de mamografía digital del programa de cribado de la Comunidad Valenciana [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1861 / Palancia
36

INFLUENCIA DE FACTORES INHERENTES AL ALIMENTO Y AL INDIVIDUO SOBRE LA DIGESTIBILIDAD DE LÍPIDOS DE ORIGEN VEGETAL

Paz Yépez, Carolina Alicia 02 September 2019 (has links)
[ES] Los lípidos en la alimentación del ser humano son esenciales para lograr una homeostasis en el individuo. Las propiedades fisicoquímicas de los lípidos están condicionadas por el origen y su estructura, determinando su interacción con otros componentes de la matriz alimentaria. Estos factores considerados como inherentes al alimento, junto con las condiciones fisiológicas del entorno digestivo de cada individuo, pueden modular la digestibilidad y la absorción intestinal de los lípidos. Así por ejemplo, en el contexto de las patologías que cursan insuficiencia pancreática exocrina (IPE) como es el caso de la fibrosis quística (FQ), la maldigestión de alimentos y malabsorción de nutrientes, especialmente de los lípidos, es una de las principales consecuencias. En estos casos, los pacientes siguen una serie de recomendaciones médicas y dietéticas que consisten en la administración de un suplemento enzimático de pancreatina encapsulada así como en un aumento de la ingesta de alimentos con alto contenido lipídico. En este escenario, los alimentos lipídicos de origen vegetal como frutos secos, semillas, así como alimentos formulados con derivados de estos, son recomendados por su perfil lipídico rico en ácidos grasos mono y poliinsaturados. La metodología de simulación in vitro de la digestión gastrointestinal permite imitar los procesos del tracto gastrointestinal estableciendo las condiciones propias del medio (pH, concentración de enzimas, sales biliares, etc.) según la etapa digestiva. Esta metodología está avalada para analizar la influencia de los diversos factores implicados en la digestibilidad y bioaccesibilidad de nutrientes en condiciones fisiológicas concretas como las determinantes de la Fibrosis Quística. El objetivo principal de esta tesis doctoral fue analizar la influencia de los factores inherentes al alimento sobre la digestibilidad lipídica y bioaccesibilidad de compuestos bioactivos en matrices alimentarias ricas en lípidos de origen vegetal. Las matrices seleccionadas fueron: semillas y germinados de chía, frutos secos (nueces y cacahuetes), chocolates (negro, con leche y blanco) y productos de panadería (pan integral, pan blanco, galletas tipo María, galletas con pepitas de chocolate, pastel de chocolate, donut, gofre, croissant y magdalenas). Otro de los objetivos fue analizar la influencia de las condiciones gastrointestinales de la FQ (pH intestinal subóptimo, secreción biliar y pancreática reducidas) sobre la lipólisis y bioaccesibilidad de compuestos bioactivos. Los resultados de esta tesis permiten afirmar que la estructura matricial, su composición, el tipo de procesado y la interacción entre nutrientes son determinantes en la lipólisis y bioaccesibilidad de algunos compuestos bioactivos en condiciones intestinales alteradas como sucede en FQ. Así por ejemplo, en el caso de la chía y los frutos secos se evidenció que un mayor nivel de desestructuración (reducción de tamaño de las matrices) resulta en una mejor digestibilidad de los macronutrientes. Por otro lado, determinados procesos como la germinación de semillas de chía se traduce en una mejora en la digestibilidad lipídica y bioaccesibilidad de compuestos fenólicos. En el caso de chocolates y productos de panadería cabe destacar que su composición (contenido y tipo de grasa, proteínas, emulsificantes, etc.) juegan un papel esencial en la digestibilidad de macro y micronutrientes. Finalmente, los ensayos realizados a distintas dosis de suplemento enzimático permitieron identificar que las dosis adecuadas para mejorar la bioaccesibilidad de compuestos bioactivos, así como para lograr una óptima extensión de la lipólisis no son únicamente en función de la cantidad de grasa. La modelización de los resultados experimentales obtenidos en cuanto a la dosificación enzimática en condiciones FQ, permitió obtener una herramienta para la predicción de la dosis óptima de enzimas reco / [CA] Els lípids en l'alimentació de l'ésser humà resulta essencial per a aconseguir una homeostasis en l'individu. Les propietats fisicoquímiques dels lípids estan condicionades per l'origen i la seua estructura, determinant la seua interacció amb altres components de la matriu alimentària. Estos factors considerats com inherents a l'aliment, junt amb les condicions fisiològiques de l'entorn digestiu pròpies de cada individu, poden modular la digestibilitat i la posterior absorció intestinal dels lípids. Així per exemple, en el context de les patologies que cursen insuficiència pancreàtica exocrina (IPE) com és el cas de la fibrosi quística (FQ), la maldigestió d'aliments i malabsorció de nutrients, especialment dels lípids, és una de les principals conseqüències. En estos casos, els pacients seguixen una sèrie de recomanacions mèdiques i dietètiques que consistixen en l'administració oral d'un suplement enzimàtic de pancreatina encapsulada així com en un augment de la ingesta d'aliments amb alt contingut lipídico. En este escenari, els aliments lipídics d'origen vegetal com a fruits secs, llavors, així com aliments formulats amb derivats d'estos, són especialment recomanats pel seu perfil lipídic, que és ric en àcids grassos mono i poliinsaturats. La metodologia de simulació in vitro de la digestió gastrointestinal permet imitar els processos del tracte gastrointestinal establint condicions pròpies del mig (pH, concentració d'enzims, sals biliars, etc.) segons l'etapa digestiva. Esta metodologia està avalada per a analitzar la influència dels diversos factors implicats en la digestibilitat i bioaccesibilidad de nutrients en condicions fisiològiques concretes com per exemple les determinants de la Fibrosi Quística. L'objectiu principal d'esta tesi doctoral va ser analitzar la influència dels factors inherents a l'aliment sobre la digestibilitat lipídica i bioaccesibilidad de compostos bioactivos en matrius alimentàries riques en lípids d'origen vegetal. Les matrius seleccionades van ser: llavors i germinats de xia, fruites seques (anous i cacauets), xocolates (negre, amb llet i blanc) i productes de forn (pa integral, pa blanc, galletes, galletes amb llavors de xocolate, pastís de xocolate, donut, gofre, croissant i magdalenes). Un altre dels objectius va ser analitzar la influencia de les condicions gastrointestinals característiques de la FQ (pH intestinal subòptim, secreció biliar i pancreàtica reduïdes) sobre la lipòlisi i bioaccesibilitat de compostos bioactivos. Així, els resultats d'esta tesi permeten afirmar que l'estructura matricial, la seua composició, el tipus de processat i la interacció entre nutrients són determinants en la lipólisis i bioaccesibilidad d'alguns compostos bioactius en condicions intestinals alterades com succeïx en FQ, tenint menor repercussió en condicions estàndards d'adult sa. Així per exemple, en el cas de la xia i els fruits secs es va evidenciar que un major nivell de desestructuració (reducció de grandària de les matrius) resulta en una millor digestibilitat dels macronutrients. D'altra banda, la germinació de llavors, de xia, millora en la digestibilitat lipídica i bioaccesibilitat de compostos fenòlics. En el cas del xocolates i productes de forn cal destacar que la seua composició (contingut i tipus de greix, proteïnes, emulsificants, etc.) juguen un paper essencial en la digestibilitat de macro i micronutrients. Finalment els assajos realitzats a distintes dosis de suplement enzimàtic van permetre identificar que les dosis adequades per a millorar la bioaccesibilidad de compostos bioactius, així com per a aconseguir una òptima extensió de la lipólisis no són únicament funció de la quantitat de greix. La modelització dels resultats experimentals obtinguts pel que fa a la dosificació enzimàtica en condicions FQ, va permetre obtindre una ferramenta per a la predicció de la dosi òptima d'enzims recomanable per / [EN] Lipids in the diet of human beings are essential to achieve a correct homeostasis in the individual. The physicochemical properties of lipids are conditioned by the origin and the structure, determining its interaction with other components of the food matrix. These factors are considered as inherent to the food, and together with the physiological conditions of the digestion lumen, can modulate the digestibility and intestinal lipid absorption. Thus, in the context of pathologies that present with exocrine pancreatic insufficiency (IPE), such as cystic fibrosis (CF), food maldigestion and malabsorption of nutrients, especially lipids, is one of the main consequences. In these cases, patients follow a series of medical and dietary recommendations, including the administration of encapsulated pancreatin enzyme supplements and high intake of lipid-rich foods. Plant-origin foods such as nuts, seeds and food formulated with derivate of these lipids are especially recommended because of their lipid profile, which is rich in mono and polyunsaturated fatty acids. The methodology of in vitro simulation of gastrointestinal digestion allows for imitating the processes of the gastrointestinal tract establishing the specific conditions (pH, concentration of enzymes, bile salts, etc.) according to the digestive stage. This methodology is endorsed to analyze the influence of various factors involved in the digestibility and bioavailability of nutrients under specific physiological conditions, such as those which are determinants of Cystic Fibrosis. The main objective of this doctoral thesis was to analyze the influence of inherent-to-food factors on the lipid digestibility and bioaccessibility of bioactive compounds in food matrices rich in vegetable lipids. The selected matrices were: seeds and sprouts of chia, nuts (walnuts and peanuts), chocolates (black, with milk and white) and bakery products (wheat bread, white bread, cookies, cookies with chocolate chips, chocolate cake, donut, waffle, croissant and muffins). Another main objective was to analyze the influence of the characteristic gastrointestinal conditions of Cystic Fibrosis (suboptimal intestinal pH, reduced biliary and pancreatic secretion) on the lipolysis and bioavailability of bioactive compounds. Thus, the results of this thesis allow us to affirm that the matrix structure, its composition, the type of processing and the interaction between nutrients, are determinants of lipolysis and bioavailability of some bioactive compounds in altered intestinal conditions as in CF. For example, in the case of chia and nuts, it was evident that a greater reduction of size of the matrices results in a better macronutrient digestibility. On the other hand, germination of chia seeds results in an improvement in the lipid digestibility and bioavailability of phenolic compounds. In the case of chocolates and bakery products it should be noted that their composition (content and type of fat, proteins, emulsifiers, etc.) play an essential role in the digestibility of macro and micronutrients. Finally the tests carried out at different doses of enzyme supplement allowed for identifying that the adequate doses to improve the bioavailability of bioactive compounds, as well as to achieve optimal lipolysis, are not only dependent of the amount of fat. The modeling of the experimental results obtained in terms of enzymatic dosing under Cystic Fibrosis conditions allowed the development of a tool for the prediction of the optimal dose of enzymes recommended for the clinical treatment in patients with cystic fibrosis. / La presente tesis doctoral ha sido desarrollada en el marco del proyecto multidisciplinar “Innovative approach for self-management and social welfare of cystic fibrosis patients in europe: development, validation and implementation of a telematics tool (MyCyFAPP)” (www.mycyfapp.eu) financiado por la Unión Europea en el contexto del Programa Horizonte 2020 (Grant Agreement: 643806). / Paz Yépez, CA. (2019). INFLUENCIA DE FACTORES INHERENTES AL ALIMENTO Y AL INDIVIDUO SOBRE LA DIGESTIBILIDAD DE LÍPIDOS DE ORIGEN VEGETAL [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/125474 / TESIS
37

Millora de la qualitat espermàtica de dosis seminals de mascles reproductors Piétrain per filtració en diverses reïnes

Bussalleu Muntada, Eva 07 March 2008 (has links)
En aquest treball s'ha dissenyat un mètode ràpid i fiable de tinció amb fluorocroms per a l'anàlisi de la integritat i viabilitat espermàtiques a partir del marcatge de la beina mitocondrial amb MitoTracker®Green FM, de l'acrosoma amb la lectina Trypsin inhibitor from Soybean (SBTI) conjugada amb el fluorocrom Alexa Fluor®488 específic per la proacrosina i del nucli amb els fluorocroms bis-benzimida (específic per a cèl·lules viables) i iodur de propidi (específic per a cèl·lules no viables). També s'ha determinat l'efecte de la filtració de dosis seminals de mascles astentoteratonecrospèrmics en columnes de Sephadex neutre i de dosis de mascles amb baixa qualitat espermàtica per filtració en columnes de Sephadex iònic, llana de vidre i glass beads sobre la qualitat espermàtica dels diferents grups de mascles analitzats. Els resultats obtinguts han mostrat que diversos paràmetres de qualitat espermàtica milloren després de la filtració en les diferents reïnes segons la patologia que presentin. / In this work, a quick and reliable method of staining with fluorochromes was designed for the assessment of the sperm integrity and vitality by marking the mitochondrial sheath with MitoTracker®Green FM, the acrosome with the lectine Trypsin inhibitor from Soybean (SBTI) conjugated with the fluorochrome Alexa Fluor ® 488m, specific for the proacrosine, and the nucleus with the fluorochromes bis-benzimida (specific for viable cells) and propidium iodide (specific for non-viable cells).Moreover, in this work, the effects of filtration of seminal doses from asthenoteratonecrospermic boars through columns of Sephadex neuter and seminal doses from boars with low sperm quality through ionic Sephadex, glass wool and glass beads columns on sperm quality were tested. The results obtained showed that some sperm quality parameters improved after filtration through the different matrixes depending on the pathology that the males presented before filtration.
38

Prescribing patterns of antidepressants with known off-label indications among adults / Jan Daniël le Roux

Le Roux, Jan Daniël January 2014 (has links)
“Off-label use” is defined as the use of medicine for indications other than recommended or registered for, e.g. the prescribing of a particular active substance for a patient younger than the substance is recommended or indicated for, or different formulations or dosages of a substance (Ekins-Daukes et al., 2004:349; Stedman’s medical dictionary, 2006). Off-label prescribing is common, and fluctuates by physician, patient and drug (Eguale et al., 2012:781). Drug classes most commonly prescribed off-label include anti-asthmatic, cardiovascular drugs and antidepressants. Lee et al. (2012:140) found that 9 out of 10 antidepressants prescribed were associated with unapproved usage of antidepressants. An antidepressant can be defined as a substance that prevents or relieves depression or depressive episodes (Mosby, 2009:115). There is paucity of information on the off-label prescribing practices of antidepressants in the South African private health sector. According to Eguale et al. (2012:781), the paucity of information on off-label prescribing practices may be, in part, ascribed to the difficulty in the establishment of reasons for treatment. The objective of this study was to determine the prescribing patterns of antidepressants as well as to identify off-label prescribing of antidepressants among adults in a section of the private health sector of South Africa by using a medicine claims database. A quantitative and observational, descriptive cross-sectional design was followed in this study. Data for a period of a year, from January to December 2010 were obtained for analysis. The data set consisted of medicine claims for a total number of 1 220 289 patients, containing a total of 8 515 428 prescriptions and 20 527 777 medicine items. The study population (patients receiving antidepressants 18 years and older) accounted for 14.8% (n = 1 220 289) of the total data set. The average age of patients receiving antidepressants was 56.1 ± 16.6 (median = 56.2) (Inter quartile range = 43.3–68.1). Results of the study showed that antidepressant prescriptions accounted for 8.3% (n = 8 515 428) of all prescriptions claimed during 2010. A total 3.5 % (n = 20 527 777) of antidepressants were claimed during the study period. Using the DU90% method it was established that the majority of antidepressant medicine items were prescribed by general practitioners (i.e. 75.7%, n = 702 285) and psychiatrists (14.9%, n = 702 285). Almost 72% (n = 702 885) of antidepressant medicine items claimed for the study population were for women. The most prescribed antidepressants (based on the DU90%) were amitriptyline (20.6%, n = 702 885), citalopram (19.2%), escitalopram (14.6%), fluoxetine (11.7%), venlafaxine (5.7%), paroxetine (5.2%), duloxetine (4.4%), sertraline (3.8%), bupropion (3.1%) and mirtazapine (2.6%). Amitriptyline accounted for 82.4% of off-label prescriptions (n = 2 635), whereas escitalopram and fluoxetine accounted for 4.2% and 3.8%, respectively. The tricyclic antidepressants (TCAs) were mostly prescribed off-label for migraine, headache and sleep disorders. The off-label prescribing of selective serotonin re-uptake inhibitors (SSRIs) included menopause, schizophrenia and headache. The off-label indicated prescriptions of the serotonin and noradrenaline re-uptake inhibitors (SNRIs) were mostly for schizophrenia and other anxiety disorders. Mirtazapine, a serotonin modulator/tetracyclic antidepressant, was mostly prescribed off-label for anxiety disorders. Off-label prescriptions for bupropion, a noradrenaline and dopamine re-uptake inhibitor mainly included other anxiety disorders and attention deficit hyperactivity disorder (ADHD). Furthermore, the prescribed daily dose (PDD) of each active antidepressant for all off-label indications was determined. In conclusion: This study investigated the off-label prescribing patterns of antidepressants among adults a section of the private health sector of a South Africa, using a large medicine claims database. Recommendations for future research were made. / MPham (Pharmacy Practice), North-West University, Potchefstroom Campus, 2014
39

Prescribing patterns of antidepressants with known off-label indications among adults / Jan Daniël le Roux

Le Roux, Jan Daniël January 2014 (has links)
“Off-label use” is defined as the use of medicine for indications other than recommended or registered for, e.g. the prescribing of a particular active substance for a patient younger than the substance is recommended or indicated for, or different formulations or dosages of a substance (Ekins-Daukes et al., 2004:349; Stedman’s medical dictionary, 2006). Off-label prescribing is common, and fluctuates by physician, patient and drug (Eguale et al., 2012:781). Drug classes most commonly prescribed off-label include anti-asthmatic, cardiovascular drugs and antidepressants. Lee et al. (2012:140) found that 9 out of 10 antidepressants prescribed were associated with unapproved usage of antidepressants. An antidepressant can be defined as a substance that prevents or relieves depression or depressive episodes (Mosby, 2009:115). There is paucity of information on the off-label prescribing practices of antidepressants in the South African private health sector. According to Eguale et al. (2012:781), the paucity of information on off-label prescribing practices may be, in part, ascribed to the difficulty in the establishment of reasons for treatment. The objective of this study was to determine the prescribing patterns of antidepressants as well as to identify off-label prescribing of antidepressants among adults in a section of the private health sector of South Africa by using a medicine claims database. A quantitative and observational, descriptive cross-sectional design was followed in this study. Data for a period of a year, from January to December 2010 were obtained for analysis. The data set consisted of medicine claims for a total number of 1 220 289 patients, containing a total of 8 515 428 prescriptions and 20 527 777 medicine items. The study population (patients receiving antidepressants 18 years and older) accounted for 14.8% (n = 1 220 289) of the total data set. The average age of patients receiving antidepressants was 56.1 ± 16.6 (median = 56.2) (Inter quartile range = 43.3–68.1). Results of the study showed that antidepressant prescriptions accounted for 8.3% (n = 8 515 428) of all prescriptions claimed during 2010. A total 3.5 % (n = 20 527 777) of antidepressants were claimed during the study period. Using the DU90% method it was established that the majority of antidepressant medicine items were prescribed by general practitioners (i.e. 75.7%, n = 702 285) and psychiatrists (14.9%, n = 702 285). Almost 72% (n = 702 885) of antidepressant medicine items claimed for the study population were for women. The most prescribed antidepressants (based on the DU90%) were amitriptyline (20.6%, n = 702 885), citalopram (19.2%), escitalopram (14.6%), fluoxetine (11.7%), venlafaxine (5.7%), paroxetine (5.2%), duloxetine (4.4%), sertraline (3.8%), bupropion (3.1%) and mirtazapine (2.6%). Amitriptyline accounted for 82.4% of off-label prescriptions (n = 2 635), whereas escitalopram and fluoxetine accounted for 4.2% and 3.8%, respectively. The tricyclic antidepressants (TCAs) were mostly prescribed off-label for migraine, headache and sleep disorders. The off-label prescribing of selective serotonin re-uptake inhibitors (SSRIs) included menopause, schizophrenia and headache. The off-label indicated prescriptions of the serotonin and noradrenaline re-uptake inhibitors (SNRIs) were mostly for schizophrenia and other anxiety disorders. Mirtazapine, a serotonin modulator/tetracyclic antidepressant, was mostly prescribed off-label for anxiety disorders. Off-label prescriptions for bupropion, a noradrenaline and dopamine re-uptake inhibitor mainly included other anxiety disorders and attention deficit hyperactivity disorder (ADHD). Furthermore, the prescribed daily dose (PDD) of each active antidepressant for all off-label indications was determined. In conclusion: This study investigated the off-label prescribing patterns of antidepressants among adults a section of the private health sector of a South Africa, using a large medicine claims database. Recommendations for future research were made. / MPham (Pharmacy Practice), North-West University, Potchefstroom Campus, 2014
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Development and evaluation of an oral fixed–dose triple combination dosage form for artesunate, dapsone and proguanil / van der Merwe, A.J.

Van der Merwe, Adriana Johanna January 2011 (has links)
Malaria is a life–threatening disease caused by Plasmodium spp and causes over one million deaths annually. The complex life cycle of the malaria parasite offers several points of attack for the antimalarial drugs. The rapid spread of resistance against antimalarial drugs, especially chloroquine and pyrimethamine–sulphadoxine, emphasises the need for new alternatives or modification of existing drugs. Artemisinin–based combination therapies (ACT’s) with different targets prevent or delay the development of drug resistance and therefore have been adopted as first–line therapy by all endemic countries. Proguanil–dapsone, an antifolate combination is more active than pyrimethamine–sulphadoxine and is being considered as an alternative to pyrimethamine–sulphadoxine. Artesunate–proguanil–dapsone is a new ACT that has wellmatched pharmacokinetics and is relatively rapidly eliminated; therefore there is a reduced risk of exposure to any single compound and potentially a decreasing risk of resistance. A few studies have been done on a triple fixed–dose combination therapy for malaria treatment and such a combination for artesunate, proguanil and dapsone are not currently investigated, manufactured or distributed. The aim of this study was to develop a triple fixed–dose combination for artesunate, proguanil and dapsone. The formulation was developed in three phases; basic formulation development, employing factorial design to obtain two possible optimised formulations and evaluating the optimised formulations. During the formulation development the most suitable manufacturing procedure and excipients were selected. A full 24 factorial design (four factors at two levels) was used to obtain the optimised formulations. As end–points to identify the optimised formulations, weight variation, friability, crushing strength and disintegration of the tablets, were used. Statistical analysis (one way ANOVA) was used to identify optimal formulations. To identify any interaction between the active pharmaceutical ingredients (API’s) and the API’s and excipients, differential scanning calorimetry was done. Flow properties of the powder mixtures (of the optimised formulations) were characterised by means of angle of repose; critical orifice diameter (COD); bulk density and tapped density; and flow rate. Tablets of the two optimised powder formulations were compressed. The tablets were evaluated and characterised in terms of weight variation, friability, crushing strength, disintegration and dissolution behaviour. Initial formulation development indicated that wet granulation was the most suitable manufacturing method. The results from the factorial design indicated that different amounts (% w/w) of the lubricant and binder as well as two different fillers influenced the weight variation, crushing strength and disintegration statistically significant. Two formulations containing two different fillers (microcrystalline cellulose or Avicel® PH 101, and lactose or Granulac® 200) were found to be within specifications and ideal for manufacturing. Tablets prepared from the FA formulation (formulation containing Avicel® PH 101) complied with the standards and guidelines for weight variation, friability, crushing strength and disintegration as set by the British Pharmacopoeia (BP). Tablets had an average crushing strength of 121.56 ± 0.022 N. Tablets disintegrated within 52.00 seconds and a maximum weight loss of 0.68% occurred during the friability test. Weight variation of the tablets prepared from the FG formulation (formulation containing Granulac® 200) complied with the standards. Average crushing strength was 91.99 ± 6.008 N and the tablets disintegrated within 140.00 seconds. Percentage friability (1.024%) did not comply with the guideline of a percentage friability of less than 1%, however, no cracked or broken tablets were seen. Dissolution showed that 98, 93 and 94% of artesunate, proguanil and dapsone were respectively released (of the label value) within 15 minutes for the FA formulations. Release of artesunate, proguanil and dapsone for the FG formulation was 62, 85 and 92% for the same time period. The release of the three API’s (the FG formulation) increased to 78, 89 and 92%, respectively, after 45 minutes. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2012.

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