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Spectroscopies vibrationnelles (MCR et ATR-FTIR) et Chromatographie Liquide couplée à la Spectrométrie de Masse Haute Résolution (LC-HR-MS) : Outils d’investigation in vivo de l’impact du vieillissement cutané sur le Stratum Corneum aux niveaux tissulaire, supra-moléculaire et moléculaire / Vibrational spectroscopies (MCR and ATR-FTI) and Liquid Chromatography coupled Mass Spectrometry High Resolution : In vivo investigation tools for the effect of skin aging on the Stratum Corneum at tissular, supra-molecular and molecular levelsBoireau-Adamezyk, Elise 22 May 2015 (has links)
La peau est l’organe le plus étendu du corps humain. Doté d’une membrane biologique fine appelée la couche cornée, celle-ci le protège du desséchement et des agressions extérieures chimiques ou mécaniques auxquelles le corps humain doit faire face. Ce travail de thèse a consisté, dans un premier temps, à décrire via la littérature existante les effets de l’âge,dûs au vieillissement intrinsèque et extrinsèque,sur la physiologie cutanée du Stratum Corneum (SC).La partie expérimentale basée sur la microscopie vibrationnelle traitera des variations de la fonction barrière et de l’hydratation du SC lors du vieillissement chronologique et photo-vieillissement. D’autres méthodes ont également été utilisées comme la chromatographie liquide en phase normale couplée à la spectrométrie de masse haute résolution dotée d’une source APCI et d’un détecteur Orbitrap pour l’étude de la composition détaillée des lipides du SC ainsi que des méthodes plus globales comme la PIE ou la cornéométrie. Le caractère non invasif de toutes ces méthodes a permis de réaliser ces études in vivo. L’évolution de la fonction barrière a été étudiée aux niveaux tissulaire, moléculaire et supramoléculaire par micro-spectroscopie confocale Raman et spectroscopie Infrarouge. Puis le lien moléculaire a été fait entre le vieillissement intrinsèque et les céramides de la matrice lipidique intercornéocytaires par chromatographie en phase liquide couplée à la spectrométrie de masse. Les molécules discriminantes entre population jeune et âgée ont été déterminées par analyse chimiométrique. L’évolution de l’hydratation cutanée aux niveaux tissulaire, moléculaire et supramoléculaire a également été l’objet d’une investigation approfondie. Les variations de la composition des NMF et la teneur en eau dans le SC lors du vieillissement cutané ont été mises en lumière en utilisant des descripteurs spectraux Raman. Les variations structurelles des molécules d’eau impactant l’organisation supramoléculaire des édifices lipidiques ont également été évaluées. Au cours du vieillissement, la fonction barrière cutanée et hydratation sont conservées. / Skin is the external surface defining the human body in space. Its outer-most layer is a thin biological membrane, called Stratum Corneum(SC), that protects the internal organs from desiccation as well as chemical or mechanical external aggressions. The present thesis aimsin a first step, to summarize the current knowledge regarding the effects of intrinsic and extrinsic aging on SCphysiology,based on available literature. The experimental part addresses the gaps in our understanding of the effects of chronological aging and photoaging on the SC barrier function and hydration, using traditional methods (such as trans epidermal water loss and skin conductance) as well as more advanced ones (vibrational spectroscopies, liquid chromatography in normal phase tandem mass spectrometry high resolution with an APCI source and an Orbitrap detector. As these methods are non-invasive, all studies have been carried out in vivo. The evolution of the barrier function has been studied at the tissular, molecular and supramolecular levels using confocal Raman micro-spectroscopy and infrared spectroscopy. Then the link between the intrinsic aging and the ceramides of the intercorneocytary lipid matrix has been studied by liquid chromatography tandem mass spectrometry. The discriminant molecules between young and old population have been identified by a chemometric analysis. The evolution of cutaneous hydration at the tissular, molecular and supramolecular level has also been investigated. The variations in the NMF composition and the SC water content have been studied by Raman spectral descriptors. Moreover, the structural variations of water molecules impacting the supramolecular organization of the lipid structures have been evaluated. Chronological aging and chronic exposure to environmental factors mildly affect SC barrier function and hydration levels. However, the processes controlling these properties are affected by aging in a site-dependent fashion.
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Molecular Epidemiology, Clinical Molecular Diagnosis and Genetic Diversity of Cutaneous Leishmaniasis in Jericho, PalestineAl-Jawabreh, Amer 17 January 2006 (has links)
In der vorliegenden Arbeit wurde die Sensitivität des Nachweises von Leishmanien in Giemsa-gefärbten Bioptaten aus Hautulzerationen mittels direkter Mikroskopie mit der Sensitivität der ITS1-PCR verglichen. Bei der ITS1-PCR wurde eine Sensitivität von 87 % mit einem positiven predictive value von 100 %, sowie eine Spezifität von 100 % mit einem negativen predictive value von 85 % nachgewiesen. Weiterhin wurden vier verschiedene Nachweismethoden miteinander verglichen: die in vitro Kultivierung in NNN Medium, die direkte Mikroskopie von Giemsa gefärbten Hautbioptaten, die PCR Amplifizierung der ITS1 Region aus auf Filterpapier aufgetragenen Hautbioptaten (FP) sowie die ITS1-PCR von ungefärbten Hautbioptaten (US). Die PCR der US erwies sich als die sensitivste Methode. Die Verbreitung von Leishmanien Arten in Jericho wurde mittels molekularer Epidemiologie untersucht. Die räumliche (Spatial) Analyse zeigte drei statistisch relevante Cluster innerhalb der kutanen Leishmaniose (CL): ein Cluster mit L. major und zwei L. tropica Cluster. Bei der Raum-Zeit–Analyse wurden vier Cluster von Kutanen Leishmaniose, zwei L. major und drei L. tropica Cluster nachgewiesen. Insgesamt 106 Stämme, die aus verschiedenen endemischen Regionen in Zentralasien, im Nahen Osten und Afrika stammen, wurden mit 10 Mikrosatellitenmarkern untersucht. Die Auswertung erfolgte über zwei Analysemethoden: die Distanz-basierte und die Modell-basierte Methode. Anhand der L. major Genomsequenz wurden PCR-Primer zur Amplifizierung von Mikrosatellitenloci von L. major entwickelt, die auf den Chromosomen 1, 3, 5, 21 und 35 liegen. Sieben unterschiedliche L. major Populationen einschließlich zweier genetisch isolierter Populationen im Nahen Osten wurden mit diesen Markern nachgewiesen. / In this study we compared the sensitivity of the diagnosis of Giemsa-stained skin scrapings by standardized graded direct microscopy with that of ITS1-PCR. ITS1-PCR showed a sensitivity of 87% with positive predictive value of 100% and a specificity of 100% with negative predictive value of 85%. In-vitro cultivation using NNN medium and direct smear microscopy of Giemsa-stained slides, PCR amplifying region 1 of internal transcribed spacer (ITS1) using skin scrapings spotted on filter papers (FP) and unstained tissue smears (US) were compared. PCR using US was more sensitive than all other methods Molecular epidemiology was used to study the distribution of Leishmania species in Jericho. Spatial analysis showed three statistically significant clusters of CL, one cluster for L. major and two clusters for L. tropica. In the case of space-time, four clusters for CL, two for L. major and three for L. tropica were detected. A total of 106 strains isolated in different endemic regions of Central Asia, Middle East and Africa were analysed using 10 pairs of microsatellite markers under two cluster methods: distance and model-based. Markers were designed to amplify microsatellite loci identified in the genome sequence of L. major on chromosomes 1, 3, 5, 21 and 35. Seven discrete populations of L. major including two genetically isolated populations in the Middle East were revealed.
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Contribuição à farmacognosia de Artemisia annua L. e Bidens pilosa L. (Asteraceae). Acompanhamento da variação de metabólitos secundários em diferentes fases fenológicas, órgãos e extratos vegetais, aspectos botânicos e avaliação da atividade antileishmania in vitro / Pharmacognosy of Artemisia annua L and Bidens pilosa L. (Asteraceae). Growth stages variation of secondary metabolites in extracts from plant parts collected in different growth stages, botanical aspects and in vitro evaluation of the antileishmanial activityFabiana Lima Silva 29 September 2008 (has links)
Na busca por espécies vegetais com atividade antileishmania, selecionaram-se, para o estudo, duas espécies bem conhecidas da família Asteraceae: Artemisia annua L. e Bidens pilosa L. Ambas são reconhecidamente utilizadas na medicina popular, como antiprotozoárias. Apesar de terem sido amplamente estudadas em diversos aspectos, alguns permaneceram inexplorados, até o momento, e foram abordados, neste trabalho. As duas espécies foram analisadas quanto aos aspectos químico e biológico de extratos (hidroetanólico e infuso) e frações orgânicas selecionados, em função da atividade antileishmania in vitro, frente às formas promastigotas de Leishmania amazonensis. Os extratos foram obtidos a partir de órgãos vegetais, em estados de conservação diferentes (in natura, droga) e coletados em fenofases distintas. Extratos e frações orgânicas das espécies estudadas mostraram promissora atividade antileishmania in vitro e baixo nível de citotoxicidade in vitro em células epiteliais humanas (HEP-2). No estudo químico dos extratos e frações bioativos, realizaram-se análises qualitativas e/ou quantitativas de terpenos, flavonóides e de marcadores específicos (artemisinina, quercetina e rutina), avaliando-se a variação da composição dos mesmos, nas diferentes fenofases consideradas. Discutiram-se as possíveis relações existentes entre a composição química e a atividade biológica verificada. Aspectos inéditos do estudo morfoanatômico de partes aéreas de A. annua foram descritos. / Plants are potential sources of new antileishmanial drugs. Two well-known antiprotozoal species were selected, from the Asteraceae family, for this study: Artemisia annua L and Bidens pilosa L. Despite the traditional and scientific accumulated knowledge, some aspects were not investigated before and were the subject of this work. Several extracts (infusions and ethanol 96 °GL) and selected fractions from both species were evaluated according to the different parameters, such as: plant organs and/or parts, growth stages and drying state of starting materials (fresh, drug). Fractions were selected among those more active against promastigotes of Leishmania amazonensis. Ethanol extracts and their fractions showed a high level of in vitro antileishmanial activity and a low cytotoxicity on epithelial human cells (HEP-2). Qualitative and/or quantitative analysis of extracts and fractions were performed for terpenes, flavonoids and selected markers (artemisinin, quercetin and rutin) in order to characterize them and evaluate variations during the different growth stages. Correlations of the chemical composition and the biological activity were discussed. The main anatomical characters of the aerial parts of A. annua were described for the first time and illustrated by photomicrographs.
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Avaliação in vitro da permeabilidade cutânea da rutina em emulsões cosméticas / In vitro evaluation of rutin cutaneous permeability from cosmetic emulsionsAndré Rolim Baby 10 September 2007 (has links)
A rutina é empregada como antioxidante e na prevenção da fragilidade capilar. Pode ser veiculada em emulsões tópicas adequadas para atingir o local de ação. Estudos de penetração in vitro através da pele humana seria a situação ideal, entretanto, há dificuldades de sua obtenção e manutenção de sua viabilidade. Entre os demais modelos de membrana, a muda de pele de cobra apresenta-se como estrato córneo puro, fornecendo barreira similar ao humano e é obtida sem a morte do animal. Os objetivos desta pesquisa foram: (1) desenvolver e avaliar a estabilidade de emulsões cosméticas, contendo rutina e promotores de penetração cutânea, tais como, uréia (U), isopropanol (IP) e propilenoglicol (PG); (2) avaliar a liberação da referida substância ativa das emulsões e; (3) avaliar a penetração e a retenção cutânea in vitro da rutina da formulação de melhor desempenho. Emulsões foram desenvolvidas com rutina a 5,0% p/p e U, IP e PG, associados ou não e em proporções distintas, segundo planejamento fatorial com dois níveis com ponto central. Quantificou-se a rutina das emulsões por espectrofotometria a 361,0 nm, método previamente validado. A liberação da rutina nas formulações foi realizada em células de difusão vertical com membrana de acetato de celulose e água destilada e álcool etílico absoluto 99,5% (1:1), como fluido receptor. O experimento foi conduzido em um período de seis horas, a 37,0 ±. 0,5 °C e agitação constante de 300 rpm.>f. emulsão de melhor desempenho quanto à liberação foi estudada quanto à estabilidade (Testes de Estabilidade Acelerada). Para o estudo de penetração e retenção cutânea da rutina dessa formulação foi utilizada muda de pele de cobra de Crotalus durissus. Empregou-se o método espectrofotométrico validado a 410,0 nm para a quantificação da rutina após liberação, penetração e retenção cutânea. Todas as emulsões foram consideradas adequadas após desenvolvimento das formulações. A uréia (isolada e em associação com IP e PG) e o isopropanol (isolado e em associação com PG) influenciaram negativamente a liberação da rutina das emulsões em diversos parâmetros. A rutina liberada e acumulada da formulação contendo PG a 5,0% p/p possuiu valor de 648,80 ±. 53,01 µg/cm2. Fora do esperado, a preparação contendo o número maior de promotores (U 5,0% p/p, IP 5,0% p/p e PG 5,0% p/p) resultou em liberação de menor magnitude igual a 419,76 ±. 17,98 µg/cm2. A presença do PG apresentou-se mais eficiente na liberação da rutina, mas não na sua penetração através da muda de pele de C. durissus, retendo 0,931 ± 0,0391 µg de rutina/mg de muda de pele de cobra. Nas condições de armazenamento a 25,0 ±2,0 °C; 5,0 ±0,5 °C e 45,0 ±. 0,5 °C, a emulsão com PG e rutina apresentou-se quimicamente estável durante 30 dias. De acordo com os resultados, a emulsão contendo PG apresentou liberação mais expressiva da rutina, no entanto, não ocorreu a penetração cutânea, mas apenas sua retenção no estrato córneo de C. durissus. A preparação manteve-se estável em todas as condições de armazenamento. / Rutin is employed as antioxidant and to prevent the capillary fragility and, when incorporated in cosmetic emulsions, it must target the action site. In vitro cutaneous penetration studies through human skin is the ideal situation, however, there are difficulties to obtain and to maintain this tissue viability. Among the membrane models, the shed snake skin presents itself as pure stratum corneum, providing barrier function similar to human and it is obtained without the animal sacrifica. The objectives of this research were: (1) development and stability evaluation of cosmetic emulsions containing rutin and penetration enhancers, as urea (U), isopropanol (IP) and propylene glycol (PG); (2) release evaluation of the mentioned active substance from the emulsions and; (3) evaluation of rutin in vitro cutaneous penetration and retention from the emulsion of the best performance. Emulsions were developed with rutin 5.0% w/wand U, IP and PG, associated or not according to factorial design with two levels and central point. Active substance on the formulations was quantified by a validated spectrophotometric method at 361.0 nm. Rutin release from emulsions was performed in vertical diffusion cells with cellulose acetate membrane and distilled water and ethanol 99.5% (1:1), as receptor fluid. The experiment was conducted for six hours, at 37.0 ± 0.5 °c with constant stirring of 300 rpm. Formulation with best profile of rutin release had its stability studied by the Accelerated Stability Assays. Rutin cutaneous penetration and retention from the mentioned emulsion was performed with shed snake skin from Crotalus durissus. Spectrophotometry at 410.0 nm, previously validated, determined the active substance after release and cutaneous penetration/retention. Ali emulsions were considered apparently stables after development. Urea (isolated and associated with IP and PG) and isopropanol (isolated and associated with PG) have influenced negatively the rutin release in several parameters. Emulsion with PG 5.0% w/w presented rutin released and accumulated equal to 648.80 ± 53.01 µg/cm2. Unexpectedly, the formulation containing all enhancers (U 5.0% w/w, IP 5.0% w/w and PG 5.0% w/w) has decreased the amount released of the active substance (419.76 ± 17.98 µg/cm2). Emulsion with PG presented more adequate for rutin release, but PG did not provide rutin cutaneous penetration through C. durissus skin, retaining 0.931 ± 0.0391 &$181;g rutin/mg shed snake skin. The referred formulation was chemically stable for 30 days after they have been stored at 25.0 ± 2.0 °c, 5.0 ± 0.5 °c and 45.0 ± 0.5 °C. In conclusion, emulsion with PG provided rutin release more expressively, although, it has not been verified the active cutaneous penetration, but only its retention on the Crotalus durissus stratum corneum. Formulation was stable in all storage conditions.
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Androgen secretion and cardiovascular risk factors in women with and without PCOS:studies on age-related changes and medical interventionPuurunen, J. (Johanna) 26 May 2015 (has links)
Abstract
Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. The main features of the syndrome include menstrual irregularities and hyperandrogenism. In addition to symptoms related to fertility, some women also suffer from an unfavourable metabolic profile including impaired glucose tolerance, dyslipidaemia and low-grade chronic inflammation.
In the present studies we aimed to investigate the role of age on adrenal and ovarian androgen secretion in 79 women with PCOS and 98 healthy women, with special focus on the menopause. Furthermore, we studied the effects of combined hormonal contraceptives (CHCs) administered orally, transdermally and vaginally (n=42, healthy women, 9 weeks) and atorvastatin treatment (n=28, women with PCOS, 6 months) on androgen levels and metabolic factors. Androgen secretion capacity was analysed by using adrenal and ovarian stimulation tests and glucose tolerance by using oral and intravenous glucose tolerance tests. Furthermore, chronic inflammation was assessed via assay of C-reactive protein and pentraxin-3.
Basal and stimulated adrenal and ovarian androgen production was elevated and levels remained higher in women with PCOS compared with healthy women even after the menopause. Furthermore, women with PCOS presented with enhanced insulin resistance and chronic inflammation, which persisted beyond menopausal transition. During CHC treatment, the route of administration was insignificant, and all treatments impaired insulin sensitivity and increased chronic inflammation. In women with PCOS, treatment with atorvastatin improved chronic inflammation and the lipid profile as expected, but worsened glucose tolerance and did not affect testosterone levels.
Regardless of strict exclusion criteria, where only relatively healthy women with PCOS were recruited, the results showed that enhanced androgen secretion and unfavourable metabolic alterations associated with PCOS persist through menopausal transition. The findings emphasize the importance of monitoring glucose metabolism during the use of CHCs, especially in women with known risks of type 2 diabetes. Atorvastatin treatment exacerbates insulin resistance in women with PCOS and therefore the treatment should only be considered after individual risk assessment of cardiovascular disease and not just because of PCOS. / Tiivistelmä
Monirakkulainen munasarjaoireyhtymä (PCOS) on hedelmällisessä iässä olevien naisten yleisin hormonaalinen ongelma. Tyypillisiä PCOS:n oireita ovat munarakkuloiden epäsäännöllisestä kypsymisestä johtuvat kuukautiskierron häiriöt ja miessukuhormonien eli androgeenien liikatuotanto. Hedelmällisyyttä heikentävien oireiden lisäksi PCOS:än liittyy aineenvaihdunnan ongelmia, kuten heikentynyttä sokerinsietoa sekä taipumus rasva-aineenvaihdunnan häiriöihin ja krooniseen tulehdukseen.
Tutkimuksessa selvitettiin ikääntymisen ja vaihdevuosien vaikutuksia lisämunuais- ja munasarjaperäiseen androgeenieritykseen 79 PCOS-naisella ja 98 terveellä naisella. Lisäksi tutkittiin eri yhdistelmäehkäisyvalmisteiden antoreittien (suu, iho, emätin) (n=42, terveet naiset, 9 viikkoa) ja atorvastatiinihoidon (n=28, PCOS-naiset, 6 kuukautta) vaikutuksia androgeenitasoihin ja aineenvaihdunnallisiin muuttujiin. Androgeenieritystä tutkittiin lisämunuaisten ja munasarjojen stimulaatiotesteillä ja sokeriaineenvaihdunnan muutoksia suun kautta ja suonensisäisesti tehtävillä sokerirasituskokeilla. Tulehduksellista tilaa mitattiin määrittämällä C-reaktiivisen proteiinin ja pentraksiini-3:n pitoisuuksia.
Lisämunuaisten ja munasarjojen androgeenieritys oli PCOS-naisilla lisääntynyt terveisiin naisiin verrattuna, ja ero säilyi vaihdevuosi-iän jälkeen. PCOS-naisilla esiintyi myös enemmän heikentynyttä sokerinsietoa ja kroonista tulehdusta vielä vaihdevuosi-iän jälkeenkin. Hormonaalinen yhdistelmäehkäisy heikensi insuliiniherkkyyttä sekä pahensi pitkäaikaista tulehdusta annostelureitistä riippumatta. Atorvastatiinihoito puolestaan paransi pitkäaikaista tulehdusta sekä rasva-aineenvaihduntaa PCOS-naisilla, mutta huononsi sokerinsietoa ja insuliiniherkkyyttä eikä sillä ollut vaikutusta testosteronitasoihin.
Koska poissulkukriteerit olivat tiukat, tutkimuksiin valikoitui varsin terveitä PCOS-naisia. Siitä huolimatta osoittautui, että PCOS:än liittyvä lisääntynyt androgeenituotanto sekä epäedulliset aineenvaihdunnan muutokset jatkuvat vielä vaihdevuosi-iän jälkeen. Hormonaalisen yhdistelmäehkäisyn käytön aikana olisi hyvä seurata sokeriaineenvaihdunnan muutoksia erityisesti niillä naisilla, joilla on kohonnut riski sairastua aikuistyypin diabetekseen. Atorvastatiinihoito huonontaa PCOS-naisilla insuliiniherkkyyttä, minkä vuoksi hoito tulisi aloittaa vain yksilöllisen riskiarvion perusteella.
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MECHANISTIC STUDIES ON THE PHOTOTOXICITY OF ROSUVASTATIN, ITRACONAZOLE AND IMATINIBNardi, Giacomo 31 March 2015 (has links)
Photosensitizing effects of xenobiotics are of increasing concern in public health
since modern lifestyle often associates sunlight exposure with the presence of chemical
substances in the skin. An important number of chemicals like perfumes, sunscreen
components, or therapeutic agents have been reported as photosensitizers.
In this context, a considerable effort has been made to design a model system for
photosafety assessment. Indeed, screening for phototoxicity is necessary at the
early phase of drug discovery process, even before introducing drugs and chemicals
into clinical therapy, to prevent undesired photoreactions in humans. In the case
of new pharmaceuticals, their phototoxic potential has to be tested when they absorb
in the regions corresponding to the solar spectrum, that is, for wavelengths
>290 nm. So, there is an obvious need for a screening strategy based on in vitro
experiments. The goal of the present thesis was the photochemical study of different
photoactive drugs to investigate the key molecular aspects responsible for their
photosensitivity side effects.
In a first stage, rosuvastatin was considered in chapter 3 as representative
compound of the statin family. This lipid-lowering drug, also known as “superstatin”,
contains a 2-vinylbiphenyl-like moiety and has been previously described
to decompose under solar irradiation, yielding stable dihydrophenanthrene analogues.
During photophysical characterization of rosuvastatin, only a long-lived
transient at ca. 550 nm was observed and assigned to the primary photocyclization
intermediate. Thus, the absence of detectable triplet-triplet absorption and
the low yield of fluorescence ruled out the role of the parent drug as an efficient
sensitizer. In this context, the attention was placed on the rosuvastatin main photoproduct
(ppRSV). Indeed, the photobehavior of this dihydrophenanthrene-like
compound presented the essential components needed for an efficient biomolecule
photosensitizer i.e. (i) a high intersystem crossing quantum yield (ΦISC =0.8), (ii)
a triplet excited state energy of ca. 67 kcal mol−1
, and (iii) a quantum yield of singlet oxygen formation (Φ∆) of 0.3. Furthermore, laser flash photolysis studies
revealed a triplet-triplet energy transfer from the triplet excited state of ppRSV
to thymidine, leading to the formation of cyclobutane thymidine dimers, an important
type of DNA lesion. Finally, tryptophan was used as a probe to investigate the
Type I and/or Type II character of ppRSV-mediated oxidation. In this way, both
an electron transfer process giving rise to the tryptophanyl radical and a singlet
oxygen mediated oxidation were observed. On the basis of the obtained results,
rosuvastatin, through its major photoproduct ppRSV, should be considered as a
potential sensitizer.
Then, itraconazole (ITZ), a broad-spectrum antifungal agent, was chosen as
main character of chapter 4. Its photochemical properties were investigated in connection
with its reported skin photosensitivity disorders. Steady state photolysis,
fluorescence and phosphorescence experiments were performed to understand ITZ
photoreactivity in biological media. The drug is unstable under UVB irradiation,
suffering a primary dehalogenation of the 2,4-dichlorophenyl moiety that occurs
mainly at the ortho-position. In poorly H-donating solvents, as acetonitrile, the
major photoproduct arises from intramolecular attack of the initially generated
aryl radical to the triazole ring. In addition, reduced compounds resulting from
homolytic cleavage of the C-Cl bond in ortho or para positions and subsequent Habstraction
from the medium are obtained to a lesser extent. In good H-donating
solvents, such as ethanol, the main photoproducts are formed by reductive dehalogenation.
Furthermore, irradiation of a model dyad containing a tryptophan unit
and the reactive 2,4-dichlorophenyl moiety of itraconazole leads to formation of
a new covalent link between these two substructures revealing that homolysis of
the C-Cl bond of ITZ can result in alkylation of reactive amino acid residues of
proteins, leading to formation of covalent photoadducts. Therefore, it has been established
that the key process in the photosensitization by itraconazole is cleavage
of the carbon-halogen bond, which leads to aryl radicals and chlorine atoms. These
highly reactive species might be responsible for extensive free radical-mediated biological
damage, including lipid peroxidation or photobinding to proteins.
In chapter 5, photobehavior of imatinib (IMT) was addressed. This is a
promising tyrosine kinase inhibitor used in the treatment of some types of human
cancer, which constitutes a successful example of rational drug design based on the
optimization of the chemical structure to reach an improved pharmacological activity.
Cutaneous reactions, such as increased photosensitivity or pseudoporphyria,
are among the most common nonhematological IMT side effects; however, the
molecular bases of these clinical observations have not been unveiled yet. Thus,
to gain insight into the IMT photosensitizing properties, its photobehavior was
studied together with that of its potentially photoactive anilino-pyrimidine and
pyridyl-pyrimidine fragments. In this context, steady-state and time resolved fluorescence,
as well as laser flash photolysis experiments were run, and the DNA
photosensitization potential was investigated by means of single strand breaks
detection using agarose gel electrophoresis. The obtained results revealed that the drug itself and its anilino-pyrimidine fragment are not DNA-photosensitizers.
By contrast, the pyridyl-pyrimidine substructure displayed a marked photogenotoxic
potential, which was associated with the generation of a long-lived triplet
excited state. Interestingly, this reactive species was efficiently quenched by benzanilide,
another molecular fragment of IMT. Clearly, integration of the photoactive
pyridyl-pyrimidine moiety in a more complex structure strongly modifies its
photobehavior, which in this case is fortunate as it leads to an improved toxicological
profile. Thus, on the bases of the experimental results, direct in vivo
photosensitization by IMT seems unlikely. Instead, the reported photosensitivity
disorders could be related to indirect processes, such as the previously suggested
impairment of melanogenesis or the accumulation of endogenous porphyrins.
Finally, a possible source of errors in the TEMPO/EPR method for singlet
oxygen detection was analyzed. For many biological and biomedical studies, it is essential
to detect the production of 1O2 and to quantify its production yield. Among
the available methods, detection of the characteristic 1270 nm phosphorescence of
singlet oxygen by time-resolved near infrared (TRNIR) emission constitutes the
most direct and unambiguous approach. An alternative indirect method is electron
paramagnetic resonance (EPR) in combination with trapping. This is based on
the detection of the TEMPO free radical formed after oxidation of TEMP (2,2,6,6-
tetramethylpiperidine) by singlet oxygen. Although the TEMPO/EPR method has
been largely employed, it can produce misleading data. This was demonstrated by
the present study, where the quantum yields of singlet oxygen formation obtained
by TRNIR emission and by the TEMPO/EPR method were compared for a set of
well-known photosensitizers. The results revealed that the TEMPO/EPR method
leads to significant overestimation of singlet oxygen yield when the singlet or triplet
excited state of the photosensitizers were efficiently quenched by TEMP, acting as
electron donor. In such case, generation of the TEMP+•
radical cation, followed by
deprotonation and reaction with molecular oxygen gives rise to a EPR detectable
TEMPO signal that is not associated with singlet oxygen production. This knowledge
is essential for an appropriate and error-free application of the TEMPO/EPR
method in chemical, biological and medical studies. / Nardi, G. (2014). MECHANISTIC STUDIES ON THE PHOTOTOXICITY OF ROSUVASTATIN, ITRACONAZOLE AND IMATINIB [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48535 / TESIS
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Rôle des afférences plantaires dans le contrôle postural et oculomoteur de sujets sains et de sujets avec Inefficience des Afférences Plantaires non symptomatique / Role of plantar afferents in postural and oculomotor control of healthy subjects and subjects with asymptomatic plantar extercoeptive inefficencyFoisy, Arnaud 27 June 2016 (has links)
Ce travail de thèse vise à évaluer le rôle des afférences cutanées plantaires dans le contrôle postural et oculomoteur en manipulant l’extéroception plantaire à l’aide de stimulations mécaniques plantaires fines. La 1ère étude a montré que des éléments médio-plantaires fins externes (EME) et surtout internes (EMI) améliorent la stabilité orthostatique et postériorisent le CPP de sujets jeunes et sains lors de mouvements des yeux. Ils ont aussi une action spécifique sur la vergence (pas sur les saccades) : les EMI augmentent l’amplitude phasique de divergence et diminuent la partie tonique, autrement dit agissent surtout sur la composante pré-programmée du mouvement ; alors que les EME agissent sur la convergence en augmentant son amplitude tonique, composante contrôlée sous influence de la rétroaction visuelle. Les inserts influent de manière directe sur le contrôle postural et oculomoteur par des voies spécifiques et indépendantes. La 2ème étude explique la variabilité des réponses des sujets de la 1ère. Nous avons mesuré leur degré d’utilisation des afférences extéroceptives plantaires par la méthode du Quotient Plantaire (QP = Surface CPP mousse / Surface CPP sol dur X 100). Un QP<100 suggère une Inefficience des Afférences Plantaires (IAP) : les sujets IAP ne présentent plus d’amélioration de leur stabilité ni aucune modification de la vergence avec les inserts plantaires. Nous proposons que cette situation soit non physiologique et relève d’un dysfonctionnement non douloureux latent des récepteurs plantaires, opposant les sujets IAP aux sujets ayant un QP normal. La 3ème étude a investigué les rapports entre l’utilisation des afférences plantaires et visuelles chez de jeunes adultes sains avec la méthode du QP et du Quotient du Romberg (QR). Elle mis en évidence l’existence d’une utilisation synergique des afférences visuelles et plantaires en vision de près, uniquement chez les sujets au QP normal. Les sujets IAP ont un QR plus bas que les sujets au QP normal, en vision de près et sur sol dur uniquement. Sur mousse, leur QR des sujets IAP augmente ; les yeux fermés, leur QP augmente, ce qui objective une asynergie visuo-podale. La 4ème étude, sur la même population, a montré qu’un EME bilatéral augmente l’esophorie, uniquement de loin et chez les sujets IAP. La 5ème étude a révélé l’influence de l’extéroception plantaire sur la perception de la Verticale Visuelle Subjective (VVS) sur la même population. Elle a montré une diminution de l’erreur vers la gauche de près chez les sujets au QP normal avec un EME droit, ainsi qu’une diminution de l’erreur absolue de loin chez les sujets IAP avec un EMI bilatéral. L’ensemble de ces travaux consolide au plan théorique l’importance des afférences plantaires aussi bien pour le contrôle orthostatique, le contrôle de la vergence, la perception de la VVS et l’alignement des yeux (phories). Ils démontrent que l’utilisation de ces afférences est variable selon les sujets et ont des implications cliniques pluridisciplinaires. / This thesis aims at assessing the role of plantar cutaneous afferents in postural and oculomotor control by manipulating plantar exteroception with thin mechanical plantar stimulations. The 1st study showed that lateral, and even more medial mid-foot plantar inserts (LAS / MAS) improve stability in quiet stance and induce a backward shift of the CoP of young healthy subjects during eye movements. They also have a specific action upon vergence (not saccades): MAS increase the phasic amplitude of divergence and decrease its tonic part, in other words they mainly act on the pre-programmed component of the movement; whereas LAS act upon convergence, increasing its tonic amplitude, which is under the influence of visual retroaction. The inserts have a direct influence upon postural and oculomotor control through specific and independent paths. The 2nd study explained the variability of the subjects’ answers of the former. We measured their degree of reliance upon plantar cutaneous afferents with the Plantar Quotient method (PQ = Surface CoP foam / Surface CoP firm gorund X 100). A PQ<100 suggest a Plantar Extercoeptive Inefficency (PEI): PEI subjects do not show any improvement of their stability or any modification of vergence with the inserts. We propose that this situation is non-physiological and results from a non-noxious latent dysfunction of the sole receptors, opposing the PEI subjects to those who have a normal PQ. The 3rd study investigated the relationship between the use of plantar and visual afferents in young healthy subjects with the method of the PQ and Romberg Quotient (RQ). It has evidenced the existence of a synergic use of visual and plantar afferents in close-distance vision, only among normal PQ subjects. The PEI subjects have a significantly lower RQ than the others only at close distance on firm ground. On foam, their RQ increases; eyes closed, their PQ increases, which objectifies a visual-podal asynergy. The 4th study, on the same population, showed that a bilateral LAS increase esophoria only at far distance and among the PEI subjects. The 5th study revealed the influence of plantar exteroception upon the perception of verticality on the same population. It has brought out a decrease of the leftward error at near distance among the normal PQ subjects with a right LAS, and a decrease of the absolute error at far distance among the PEI subjects with a bilateral MAS. Taken together, these studies support, from a theoretical point of view, the importance of plantar afferents for postural control as well as vergence control, SVV estimation and eyes alignment (phorias). They demonstrate that the use of these afferents depends on the subjects and have multidisciplinary clinical implications.
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Ipsi- and contralateral corticospinal influences in uni- and bimanual movements in humansDuval, Laura 04 1900 (has links)
Il existe des projections corticospinales (CS) vers les motoneurones (MNs) aussi bien contra- (c)
qu’ipsilatérales (i). Les influences CSc sur les MNs du poignet sont connues pour être modulées
entre autres par la position du poignet et les afférences cutanées. Pour cette raison, notre objectif
était de vérifier si ces caractéristiques sont aussi valides pour les influences CSi. En utilisant la
stimulation transcrânienne magnétique au niveau du cortex primaire droit, nous avons tout
d’abord comparé les influences CSi sur les MNs des fléchisseurs du poignet à des positions
maintenues de flexion et d’extension durant une tâche uni-manuelle ainsi que deux tâches bimanuelles,
ceci chez des sujets droitiers (n=23). Nous avons ensuite comparé les influences CSi
dans cinq tâches bi-manuelles de tenue d’objet durant lesquelles les sujets avaient à tenir entre
leurs mains un bloc à la surface soit lisse, soit rugueuse, dont le poids était supporté ou non, ceci
en position de flexion (n=21). Dans une tâche, un poids était ajouté au bloc lisse en condition non
supportée pour amplifier les forces de préhension requises. Une modulation positiondépendante
était observée au niveau des potentiels évoqués moteurs (iPEM), mais seulement
lors de la tâche bi-manuelle quand les deux mains interagissaient via un bloc (p= 0.01). Une
modulation basée sur la texture était également présente, quel que soit le support de poids, et le
bloc lisse était associé avec des iPEMs plus importants en comparaison avec le bloc rugueux (p=
0.001). Ainsi, les influences CSi sur les MNs n’étaient modulées que lors des tâches bi-manuelles
et dépendaient de la manière dont les mains interagissaient. De plus, les afférences cutanées
modulaient les influences CSi facilitatrices et pourraient ainsi participer à la prise en main des
objets. Il en est conclu que les hémisphères droit et gauche coopèrent durant les tâches bimanuelles
impliquant la tenue d’objet entre les mains, avec la participation potentielle de
projections mono-, et poly-synaptiques, transcallosales inclues. La possibilité de la contribution
de reflexes cutanés et d’étirement (spinaux et transcorticaux) est discutée sur la base de la notion
que tout mouvement découle du contrôle indirect, de la « référence » (referent control). Ces
résultats pourraient être essentiels à la compréhension du rôle des interactions interhémisphériques
chez les sujets sains et cliniques. / There are both contra- (c) and ipsilateral (i) corticospinal (CS) projections to motoneurons (MNs).
There is evidence that cCS influences on wrist MNs are modulated by wrist position and
cutaneous afferents. Thus, we aimed to test whether these findings are valid for iCS influences as
well. Using transcranial magnetic stimulation applied over the right primary motor cortex, we first
compared iCS influences on wrist flexor MNs at actively maintained flexion and extension wrist
positions in one uni- and two bimanual tasks in right-handed subjects (n=23). We further
compared iCS influences in five bimanual holding tasks in which subjects had to hold a smooth or
coarse block between their hands, with or without its weight being supported, in flexion position
(n=21). In one task, a weight was added to the unsupported smooth block to increase load forces.
A position-dependent modulation of the short-latency motor evoked potential (iMEP) was
observed, but only in the bimanual task when the two hands interacted through a block (p=0.01).
A texture-dependent modulation was present regardless of the weight supported, and the
smooth block was associated with larger iMEPs in comparison to the coarse block (p=0.001).
Hence, iCS influences on MNs were modulated only in bimanual tasks and depended on how the
two hands interacted. Furthermore, cutaneous afferents modulated facilitatory iCS influences
and thus may participate to grip forces scaling and maintaining. It is concluded that the left and
right cortices cooperate in bimanual tasks involving holding an object between the hands, with
possible participation of mono- and poly-synaptic, including transcallosal projections to MNs. The
possible involvement of spinal and trans-cortical stretch and cutaneous reflexes in bimanual tasks
when holding an object is discussed based on the notion that indirect, referent control underlies
motor actions. Results might be essential for the understanding of the role of intercortical
interaction in healthy and neurological subjects.
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Klinickopatologické a molekulárně biologické charakteristiky vybraných kožních epiteliálních a neepiteliálních nádorů / Clinicopathological and molecular biologic characteristics of selected cutaneous epithelial and nonepithelial tumorsKastnerova, Liubov January 2019 (has links)
The doctoral thesis MD. Liubov Kastnerova (previous name Kyrpychova) is focused on the histomorphological and molecular biologic features of selected cutaneous epithelial and nonepithelial tumors and is structured as a commentary to the 20 articles published during four years, representing the completed scientific projects in the Ph.D. course. In eight papers, the author of the thesis is the first author, whereas she coauthored in the remaining 12 papers. The thesis is composed of the commented files of authors own publications and it is divided into cutaneous epithelial and nonepithelial tumors. The first section, «Cutaneous epithelial tumors», includes 14 articles that are subdivided into two parts: adnexal tumors (9 articles) and lesions of anogenital mammary-like glands (5 articles). Of the nine articles on adnexal tumors, there are 5 articles focused on various benign and malignant adnexal lesions with apocrine or eccrine differentiation. Novel findings in this part include the identification of hitherto unreported alterations of the MYBL1 gene in adenoid cystic carcinoma of the skin and lack of deletion of the 1p36 locus in this neoplasm; the lack of a correlation between cellular composition and the presence CRTC1-MAML2 fusions in hidradenoma, the absence of CRTC3-MAML2 fusions in this tumor,...
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CURE RATE AND DESTRUCTIVE CURE RATE MODELS UNDER PROPORTIONAL ODDS LIFETIME DISTRIBUTIONSFENG, TIAN January 2019 (has links)
Cure rate models, introduced by Boag (1949), are very commonly used while modelling
lifetime data involving long time survivors. Applications of cure rate models can be seen
in biomedical science, industrial reliability, finance, manufacturing, demography and criminology. In this thesis, cure rate models are discussed under a competing cause scenario,
with the assumption of proportional odds (PO) lifetime distributions for the susceptibles,
and statistical inferential methods are then developed based on right-censored data.
In Chapter 2, a flexible cure rate model is discussed by assuming the number of competing
causes for the event of interest following the Conway-Maxwell (COM) Poisson distribution,
and their corresponding lifetimes of non-cured or susceptible individuals can be
described by PO model. This provides a natural extension of the work of Gu et al. (2011)
who had considered a geometric number of competing causes. Under right censoring, maximum likelihood estimators (MLEs) are obtained by the use of expectation-maximization
(EM) algorithm. An extensive Monte Carlo simulation study is carried out for various scenarios,
and model discrimination between some well-known cure models like geometric,
Poisson and Bernoulli is also examined. The goodness-of-fit and model diagnostics of the
model are also discussed. A cutaneous melanoma dataset example is used to illustrate the
models as well as the inferential methods.
Next, in Chapter 3, the destructive cure rate models, introduced by Rodrigues et al. (2011), are discussed under the PO assumption. Here, the initial number of competing
causes is modelled by a weighted Poisson distribution with special focus on exponentially
weighted Poisson, length-biased Poisson and negative binomial distributions. Then, a damage
distribution is introduced for the number of initial causes which do not get destroyed.
An EM-type algorithm for computing the MLEs is developed. An extensive simulation
study is carried out for various scenarios, and model discrimination between the three
weighted Poisson distributions is also examined. All the models and methods of estimation
are evaluated through a simulation study. A cutaneous melanoma dataset example is used
to illustrate the models as well as the inferential methods.
In Chapter 4, frailty cure rate models are discussed under a gamma frailty wherein the
initial number of competing causes is described by a Conway-Maxwell (COM) Poisson
distribution in which the lifetimes of non-cured individuals can be described by PO model.
The detailed steps of the EM algorithm are then developed for this model and an extensive
simulation study is carried out to evaluate the performance of the proposed model and the
estimation method. A cutaneous melanoma dataset as well as a simulated data are used for
illustrative purposes.
Finally, Chapter 5 outlines the work carried out in the thesis and also suggests some
problems of further research interest. / Thesis / Doctor of Philosophy (PhD)
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