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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Identificação de patógenos causadores de mastite subclínica por espectrometria de massas / Identification of subclinical mastitis pathogens causing by mass spectrometry

Juliana Regina Barreiro 19 January 2011 (has links)
O diagnóstico rápido e eficiente da mastite subclínica é importante para reduzir a persistência da doença e os prejuízos decorrentes. O objetivo do estudo foi avaliar a técnica de espectrometria de massas (MS) por ionização e dessorção a laser assistida por matriz - tempo-de-vôo (MALDI-TOF) para identificação de bactérias causadoras de mastite subclínica bovina por dois métodos: 1) a partir de bactérias isoladas por cultivo icrobiológico; 2) a partir da recuperação de bactérias diretamente do leite, visando eliminar completamente a necessidade de cultivo microbiológico para identificação dos patógenos. O estudo foi composto por dois experimentos (1 e 2), no experimento 1 foram utilizadas 33 amostras de leite provenientes de animais das raças Gir e Holandesa de quatro fazendas leiteiras para a identificação icrobiológica e MALDI-TOF MS. As amostras com resultados conflitantes foram confirmadas por sequenciamento do gene 16S rRNA. Os resultados de cultura microbiológica foram Staphylococcus aureus (n = 13), Streptococcus agalactiae (n = 10) e Estafilococos coagulase negativo (ECN) (n = 10). Para todas as amostras de Streptococcus agalactiae, resultados similares foram observados para a identificação microbiológica e por MALDI-TOF MS. De 13 isolados de Staphylococcus aureus, 11 foram igualmente identificados por MALDITOF, 1 isolado foi identificado como Staphylococcus haemolyticus por sequenciamento do gene 16S rRNA, e o outro isolado isolado com resultado conflitante foi caracterizado como cultura mista de Staphylococcus aureus e Enterococcus faecalis. Em relação às amostras de ECN, todas as amostras do grupo foram identificadas por MALDI-TOF em nível de gênero (S. simulans, S. epidermidis, S. Haemolyticus, S. Chromogens e S. aureus coagulase negativa). No experimento 2 foi avaliado o método de recuperação de bactérias presentes em leite e sua identificação por MALDI-TOF MS utilizando o método de contaminação experimental de leite com Escherichia coli, Enterococcus faecalis e Staphylococcus aureus. A identificação de patógenos recuperados diretamente do leite foi possível quando a concentração de E. faecalis e S. aureus foi de 106 ufc/mL, e de 107 ufc/mL para E.coli. Concluímos que o uso de MALDI-TOF MS pode acelerar a identificação de patógenos causadores de mastite subclínica bovina podendo contribuir para a adoção de medidas de controle e tratamento mais adequado. / Rapid and efficient diagnosis of subclinical mastitis is important to reduce the persistence of the disease and its losses. This study aimed to evaluate the technique of mass spectrometry (MS) and desorption ionization by matrix assisted laser time-offlight (MALDI-TOF) for identification of bacteria causing bovine subclinical mastitis by two methods: 1) from bacteria isolated by microbiological culture, 2) from bacteria recovered directly from milk, to eliminate completely the need for microbiological culture for identification of pathogens. The study consisted of two experiments (1 and 2).In experiment 1, 33 milk samples from Gir and Holstein animals collected in four dairy farms were used for microbiological identification and MALDI-TOF MS. The samples with different results were confirmed by sequencing the 16S rRNA. These samples were identified by microbiological culture as Staphylococcus aureus (n = 13), Streptococcus agalactiae (n = 10) and Staphylococcus coagulase negative (SCN) (n = 10). For all strains of Streptococcus agalactiae, similar results were observed for microbiological identification and MALDI-TOF MS. From 13 isolates of Staphylococcus aureus, 11 were also identified by MALDI-TOF, one isolate was identified as Staphylococcus haemolyticus by 16S rRNA sequencing , and the other discrepant sample was charactezided a mixed culture of Staphylococcus aureus and Enterococcus faecalis. Regarding the SCN samples, all samples of this group were identified by MALDI-TOF at gender level (S. simulans, S. epidermidis, S. haemolyticus, S. Chromogens and S. aureus coagulase negative). In experiment 2, we evaluated the method of recovery of bacteria present in milk and their identification by MALDI-TOF MS using experimental method of contamination of milk with Escherichia coli, Enterococcus faecalis and Staphylococcus aureus. The identification of pathogens recovered directly from milk was possible when the concentration of E. faecalis and S. aureus was 106 ufc/mL and 107 ufc/mL for E.coli. We conclude that the use of MALDI-TOF MS can accelerate the identification of pathogens causing bovine subclinical mastitis may contribute to the adoption of control measures and appropriate treatment.
182

The effect of low temperature and transportation time on Clostridium difficile viability

Hörnström, Eva January 2016 (has links)
Anaerobe opportunist Clostridium difficile causes the majority of hospital-acquired antibiotic-associated diarrhea. Infections can be severe because of its ability to withstand many antibiotics, to sporulate and to produce toxins (A, B and binary).     In Sundsvall Hospital C. difficile is detected with real-time PCR, which targets the sequences of toxin B, binary toxin and a regulatory gene deletion seen in the virulent ribotype 027. All positive samples are stored frozen for one month, available for further analysis or outbreak investigation. The aim of this study was to investigate if temperature and transportation time may affect the viability of C. difficile, and the PCR-result.     Frozen feces samples were cultivated, identified with MALDI-TOF and analyzed with real-time PCR after at least one month of storage. To simulate the effect of transportation time, samples were stored at 4-8°C for three and seven days before cultivation and identification. Controls were cultivated after freezing for comparison.     Ninety percent of the frozen samples contained viable C. difficile. Discrepancies between PCR-results were found for two of the oldest samples collected (six months), which turned negative. Fresh samples showed lower amount of viable C. difficile after three days (50 %) than after seven days (60 %) of storage, perhaps because of competition with other bacteria and sporulation. The frozen control group contained a higher viable amount, 75 %. The results indicate that C. difficile tolerates to be stored at low temperatures as practiced today at the laboratory. Transportation time seem to affect the outcome of cultivation, but not the PCR-result.
183

Bactéries associées à l'éponge Méditerranéenne Crambe crambe : diversité et possible rôle dans la biosynthèse des alcaloïdes guanidiniques / Bacteria associated to the Mediterranean sponge Crambe crambe : diversity and possible role in the biosynthesis of guanidine alkaloids

Croué, Julie 18 September 2014 (has links)
Crambe crambe (Schmidt, 1862), espèce largement retrouvée en Méditerranée, est la source de nombreuxalcaloïdes guanidiniques (crambescines et crambescidines). Les voies de biosynthèse de ces métabolitessecondaires n’ont pas encore été démontrées. Il a cependant été proposé que les crambescidines seraientproduites à partir de polycétides, suggérant ainsi la possible implication de micro-organismes dans leurbiosynthèse. Cependant les quelques études portant sur la présence ou non de bactéries associées à cette épongesont contradictoires. Durant cette thèse, nous avons caractérisé la communauté bactérienne associée à C. crambepar l’utilisation de techniques à la fois moléculaires et microscopiques, mettant en évidence l’associationspécifique entre une bêtaprotéobactérie et cette éponge méditerranéenne. La présence d’un micro-organismespécifique au sein du mésohyle de l’éponge pose alors la question du rôle de ce dernier au sein de son hôte etplus particulièrement sa possible implication dans la synthèse des alcaloïdes guanidiniques. L’étude de ladiversité microbienne cultivable par la mise en place d’une procédure d’acclimatation et la conception de diversmilieux de cultures, a permis l’isolement de micro-organismes minoritairement associés à C. crambe, mais n’acependant pas conduit à l’isolement de la bêtaprotéobactérie spécifique. La comparaison des empreinteschimiques (CLHP/DAD/ELSD – CLHP/ESIMS) des extraits de l’éponge et des bactéries cultivées, a révélé queces micro-organismes minoritaires n’étaient pas à eux seuls producteurs de ces métabolites bioactifs. La bactériemajoritaire, principale candidate dans la synthèse des métabolites n’étant pas cultivable, nous avons développédeux études complémentaires afin d’apporter des éléments de réflexion quant à sa possible implication. Laculture ex situ de colonies C. crambe accompagnée d’un stress pH ainsi que l’étude de la distribution spatiale insitu des composés par imagerie par spectrométrie de masse se révèlent prometteuses bien qu’elles n’aient pas, àce jour permis d’identifier le possible rôle de la bêtaprotéobactérie dans la biosynthèse de ces métabolites. / Crambe crambe (Schmidt, 1862), is a marine sponge widely distributed in the Mediterranean Sea and known toproduce bioactive guanidine alkaloids (crambescins and crambescidins). While the biosynthetic pathways ofthese metabolites remains unknown, bio-mimetic chemical synthesis of crambescidins suggested a possiblecontribution of microorganisms in their biosynthesis. Contrastingly, it had been reported via electron microscopythat bacteria were absent in the tissues of this sponge. Thus to shed light onto these contrasting results I studiedthe microbial community associated with C. crambe using alternative approaches. Using molecular andmicroscopic techniques, we demonstrated that a single bacterial species affiliated to the Betaproteobacteria ispresent in abundances commonly found in low microbial abundance sponges, and dominates the bacterialcommunity associated with C. crambe. This finding suggests a possible implication of bacteria the biosynthesisof C. crambe’s guanidine alkaloids. The use of acclimatization procedure and diverse cultivation approachesallowed the isolation of associated microorganisms which were rare or absent among the community describedvia tag pyrosequencing but not isolation of the dominant betaproteobacterium. CLHP/DAD/ELSD andCLHP/ESIMS fingerprints of extracts from C. crambe and from the isolated bacteria showed no evidence of theimplication of these cultured micro-organismes in the synthesis of C. crambe’s metabolites. Finally in order toevaluate the potential role of the uncultivated betaproteobacterial symbiont in the biosynthesis of guanidiniumalkaloids, preliminary experiments using two alternative approaches were attempted. In the first I subjectedsponges to a pH stress and evaluated changes in secondary metabolite profiles, while collecting samples formicrobial community analysis. In the second I tried different mass spectrometry imaging techniques to localizeguanidinium alkaloids in C. crambe tissues. While these experiments did not allow to resolve the question of apossible implication of the dominant betaproteobacterium in the biosynthesis of the pentacyclic guanidinealkaloids, I was able to gather interesting results that will guide future studies towards resolving this question.
184

Untersuchungen zum direkten und indirekten Nachweis von Labormausinfektionen mit Rodentibacter heylii, Rodentibacter pneumotropicus und Muribacter muris

Kähl, Sophie 10 August 2021 (has links)
Einleitung Rodentibacter (R.) pneumotropicus und R. heylii sind wichtige Pneumonie-, Otitis- und Mastitiserreger in Labormäusen. Auf Grund der hohen Prävalenz und Relevanz für tierexperimentelle Studien sind gut etablierte diagnostische Methoden entscheidend. Die bisherigen Möglichkeiten der Diagnostik sind jedoch nicht zufriedenstellend. Auch die Differenzierung zu Muribacter (M.) muris, einer apathogenen Pasteurellaceae, ist nicht mit allen Methoden möglich. Die Pathogenese von Infektionen mit Rodentibacter spp. ist bis heute nicht endgültig beschrieben und auch Virulenzfaktoren sind nur in Form rekombinanter Proteine in vitro untersucht. Ziele der Untersuchung Diese Doktorarbeit verfolgte die Ziele, den direkten Erregernachweis wichtiger muriner Pasteurellaceae über MALDI-TOF MS zu etablieren und zu evaluieren und indirekte spezifische und sensitive Nachweisverfahren (ELISA) von Labormausinfektionen mit R. pneumotropicus und R. heylii im Rahmen eines Verbundprojektes zu entwickeln. Des Weiteren sollte ein neu identifiziertes Immunogen eines hochvirulenten R.-heylii-Stammes geno- und phänotypisch analysiert und charakterisiert werden. Material und Methoden In der ersten Publikation wurden Feldisolate und Referenzstämme der Spezies R. pneumotropicus, R. heylii, R. ratti und M. muris mittels 16S rRNA identifiziert und daraus Referenzspektren zur Erweiterung der MALDI-TOF MS-Datenbank erstellt. Die Evaluierung fand mittels Abgleiches mit einer etablierten Multiplex-PCR und bereits publizierter Stämme statt. Für die zweite Publikation wurden BALB/c- und C57BL/6-Mäuse mit R. heylii SF27GVG oder M. muris infiziert. Als Readout Parameter wurde ein klinischer und pathologischer Score eingesetzt. Weiterhin erfolgte eine quantitative oder semiquantitative bakteriologische Untersuchung unterschiedlicher Gewebe und Körperflüssigkeiten sowie eine serologische Untersuchung auf Serokonversion mit unterschiedlichen ELISAs. Das durch Immunoproteomics identifizierte R. heylii Immunogen A (RhiA) wurde nach in silico Analysen in trunkierter Form rekombinant exprimiert und zur Etablierung eines ELISA genutzt. Die phänotypische Charakterisierung fand mittels Western Blot, Durchflusszytometrie und Immunhistochemie statt. Hierfür wurde ein RhiA-spezifischer IgY-Antikörper eingesetzt. In der dritten Publikation wurde das Protein CARLO-1 kloniert und rekombinant exprimiert. Der neu etablierte ELISA wurde mit Hilfe von Rekonvaleszenzseren verschiedener Tierversuche evaluiert und außerdem die Konservierung des entsprechenden Gens in R. heylii und R. pneumotropicus-Stämmen analysiert. In der vierten Studie wurde das für BALB/c-Mäuse bereits etablierte R. pneumotropicus Infektionsmodell eingesetzt, um die Schutzwirkung einer Inaktivatvakzine vor einer Infektion der Lunge mit diesem Pathogen zu ermitteln. Ergebnisse Die erweiterte MALDI-TOF MS-Datenbank ermöglicht eine sichere Differenzierung zwischen R. heylii, R. pneumotropicus, R. ratti und M. muris, wie die Übereinstimmungen zu Ergebnissen der Multiplex-PCR zeigen. Im Tierversuch zeigte sich, dass R. heylii SF27GVG hoch virulent ist, obwohl dieser Stamm keines der bekannten RTX-Proteine trägt. Das identifizierte Immunogen RhiA dieses Stammes liegt oberflächenassoziiert vor, wird in vitro und in vivo exprimiert und hat strukturelle Ähnlichkeiten zu PnxIII. Es kann in infizierten Lungen assoziiert mit Bakterienrasen nachgewiesen werden und ist als RTX-Adhäsin möglicher Weise an der Biofilmproduktion beteiligt. RhiA ist hoch spezifisch für R. heylii (ELISA-Spezifität 100%). Es wird aber nur von wenigen der untersuchten Stämme gebildet. Der CARLO-1-ELISA zeigt eine Sensitivität von 93,3% und eine Spezifität von 100%. Das kodierende Gen ist in allen untersuchten R. heylii und R. pneumotropicus-Stämmen konserviert. Mit dem in einer vorausgegangenen Dissertation etablierten R. pneumotropicus Infektionsmodell konnte die protektive Wirkung einer neuen Inaktivatvakzine erfolgreich bestätigt werden. Schlussfolgerungen Nach Erweiterung der Datenbank können R. heylii, R. pneumotropicus und M. muris mittels MALDI-TOF MS differenziert werden. RhiA ist ein hochspezifisches, repetitives, Oberflächen-assoziiertes und in Lungenläsionen exprimiertes RTX-Immunogen, das von einem hochvirulenten R.-heylii-Pathotyp gebildet wird. Durch die Unterstützung von Kooperationspartnern konnte der CARLO-1-ELISA als spezifisches und sensitives indirektes Nachweisverfahren für Infektionen mit R. pneumotropicus oder R. heylii etabliert und evaluiert werden. Weiterhin wurde erstmalig gezeigt, dass sich mit dem R. pneumotropicus Infektionsmodell die protektive Wirkung einer Inaktivatvakzine aufzeigen lässt.:I. Inhaltsverzeichnis I II. Abkürzungsverzeichnis III 1 Einleitung 1 2 Literaturübersicht 2 2.1 Taxonomie 2 2.1.1 Pasteurellaceae 2 2.1.2 Rodentibacter spp. 5 2.1.3 Muribacter muris 5 2.2 Klinik und Virulenzfaktoren 7 2.2.1 Pasteurellaceae 7 2.2.2 Rodentibacter heylii und Rodentibacter pneumotropicus 11 2.3 Diagnostik 13 2.3.1 Pasteurellaceae 13 2.3.1.1 Monitoring 13 2.3.1.2 Direkte Diagnostik 14 2.3.1.3 Indirekte Diagnostik 20 2.3.2 Rodentibacter heylii und Rodentibacter pneumotropicus 22 2.3.3 Muribacter muris 23 3 Publikationen 25 3.1 Differentiation of Rodentibacter pneumotropicus, Rodentibacter heylii and Muribacter muris by MALDI-TOF MS 25 3.2 Identification of a large repetitive RTX immunogen in a highly virulent Rodentibacter heylii strain 31 3.3 Sensitive and immunogen-specific serological detection of Rodentibacter pneumotropicus infections in mice 43 3.4 Low-Energy Electron Irradiation Efficiently Inactivates the Gram-Negative Pathogen Rodentibacter pneumotropicus—A New Method for the Generation of Bacterial Vaccines with Increased Efficacy 57 4 Diskussion 69 5 Zusammenfassung 75 6 Summary 77 7 Literaturverzeichnis 79 8 Anhang 93 8.1 Anhang zu „Identification of a large repetitive RTX immunogen in a highly virulent Rodentibacter heylii strain” 93 8.2 Anhang zu “Sensitive and immunogen-specific serological detection of Rodentibacter pneumotropicus infections in mice“ 102 8.3 Anhang zu “Low-Energy Electron Irradiation Efficiently Inactivates the Gram-Negative Pathogen Rodentibacter pneumotropicus—A New Method for the Generation of Bacterial Vaccines with Increased Efficacy” 123 Danksagung 125
185

Biotypizace askomycetních kvasinek / Biotyping of ascomycetous yeasts

Jurnečková, Alena January 2017 (has links)
In total, 84 yeast strains (originated from water, plants, fruits and soil) were selected for MALDI-TOF biotyping. All strains were cultivated on malt agar and YPD medium. Samples for biotyping were processed according to methods of Bruker Daltonik GmbH company, Institute of Chemistry of SAS and combination of these methods. Single strains were identified based on the analysis of intracellular ribozomal proteins using MALDI-TOF mass spectrometry. In case of ambiguous results, the DNA was isolated and the D1/D2 26S rRNA domain sequencing was performed. The strain identification was carried out by comparing its mass spectra with spectra of sequenced strains using MALDI Biotyper 3.0 software. The mutual similarity of strains was considered by score value, which was the result of the analysis. In total, 18 strains from 84 were previously sequenced and used as model strains for comparison with unknown isolates. Altogether 51 strains were definitely taxonomically categorized into 18 phylogenetic groups at the species level. The MALDI-TOF biotyping was repeated for overall 6 strains because of ambiguity of results. The taxonomic classification of 15 strains was not clearly determined and, therefore, these strains were suggested for D1/D2 26S rRNA domain sequencing. It was not possible to identify one strain, based on the results of sequencing, therefore, the DNA isolation was repeated. In the case of 8 strains, the results were identical with originally designed taxonomic classification. Conversely, the remaining 6 strains were identified as species. For 20 selected strains the basic characteristics were determined using microbiological methods. The shape of colonies growing on solid medium and appearance of cultures in liquid medium was assessed. Furthermore, the radial growth constant and the presence of urease were determined. Finally the microscopic observation of cells and the fermentation test for carbohydrate substrates were performed.
186

Analýza antimikrobiálních peptidů v jedových žlázách čmeláků / Analysis of antimicrobial peptides in venom glands of bumblebees.

Janechová, Daniela January 2012 (has links)
The growing resistance of bacteria to traditional antibiotics promotes the interest in finding new substances for their production. Antimicrobial peptides have comparable effect to conventional antibiotics, but a different mechanism of action and they do not provoke bacterial resistance. These peptides were characterized in all forms of multicellular organisms. Hymenoptera venom contains many biologically active substances including antimicrobial peptides. For this reason, this thesis focuses on the acquisition of antimicrobial peptide sequences from selected species of bumblebees (Bombus terrestris, B. hortorum, B. hypnorum, B. pratorum, B. lucorum, B. lapidarius, B. humilis and B. bohemicus). The isolation from the venom glands was performed by high performance liquid chromatography with reversed phases. Subsequent analysis was performed using the methods of mass spectrometry, matrix-assisted laser desorption/ionization with time of flight analyzer and electrospray ionization connected with hybrid linear ion trap analyzer with orbitrap. The sequences for the found peptides were determined by tandem mass spectrometry methods "de novo" and Edman degradation. In this work we characterized 17 sequences of peptides extracted from bumblebee venom glands for which antimicrobial activity was determined...
187

Oral brush biopsy analysis by MALDI-ToF Mass Spectrometry for early cancer diagnosis

Maurer, Katja 10 June 2013 (has links)
Objectives: Intact cell peptidome profiling (ICPP) with MALDI-ToF Mass-Spectrometry holds promise as a non invasive method to detect head and neck squamous cell carcinoma (HNSCC) objectively, which may improve the early diagnosis of oral cancer tremendously. The present study was designed to discriminate between tumour samples and non-cancer controls (healthy mucosa and oral lesions) by analysing complete spectral patterns of intact cells using MALDI-ToF MS. Material and Methods: In the first step, a data base consisting of 26 patients suffering from HNSCC was established by taking brush biopsy samples of the diseased area and of the healthy buccal mucosa of the respective contralateral area. After performing MALDI-ToF MS on these samples, classification analysis was used as a basis for further classification of the blind study composed of additional 26 samples including HNSCC, oral lesions and healthy mucosa. Results: By analyzing spectral patterns of the blind study, all cancerous lesions were defined accurately. One incorrect evaluation (false positive) occurred in the lesion cohort, leading to a sensitivity of 100%, a specificity of 93% and an overall accuracy of 96.5%. Conclusion: ICPP using MALDI-ToF MS is able to distinguish between healthy and cancerous mucosa and between oral lesions and oral cancer with excellent sensitivity and specificity, which may lead to a more impartial early diagnosis of HNSCC.
188

MALDI-TOF MS Data Processing Using Wavelets, Splines and Clustering Techniques.

Chen, Shuo 18 December 2004 (has links) (PDF)
Mass Spectrometry, especially matrix assisted laser desorption/ionization (MALDI) time of flight (TOF), is emerging as a leading technique in the proteomics revolution. It can be used to find disease-related protein patterns in mixtures of proteins derived from easily obtained samples. In this paper, a novel algorithm for MALDI-TOF MS data processing is developed. The software design includes the application of splines for data smoothing and baseline correction, wavelets for adaptive denoising, multivariable statistics techniques such as clustering analysis, and signal processing techniques to evaluate the complicated biological signals. A MatLab implementation shows the processing steps consecutively including step-interval unification, adaptive wavelet denoising, baseline correction, normalization, and peak detection and alignment for biomarker discovery.
189

Dysbiosis of the urinary microbiome - a potential cause for cystitis in women

Näslund, Sandra January 2023 (has links)
Background: Urinary tract infection (UTI) is a common bacterial infection that is usually diagnosed by symptoms such as dysuria and frequency, and the golden standard is to take a urine culture to identify bacteria that may cause UTI. This method was founded with the idea that normal urine is sterile, but this is now being questioned because of growing evidence of a urinary microbiota thus giving a new approach to methods for UTI diagnosis. Aim: To identify and re-evaluate findings of bacteria from urine cultures in the ongoing paradigm shift of a potential urinary microbiome, and dysbiosis as a cause for UTI. Materials and Methods: This study used MALDI-TOF MS to identify approximately 250 bacteria isolates that had been cultured by Expanded Quantitative Urine Culture (EQUC) from 162 women with symptoms of cystitis. EQUC had allowed the bacteria to grow in both CO2 and anaerobic conditions, which differs from standard techniques.   Results and Conclusion: Escherichia coli and Enterococcus faecalis dominated the results of most frequently identified bacteria. However, other bacteria were commonly present within the same culture which is traditionally considered as contamination but may now indicate a urinary flora. Anaerobic bacteria – such as Porphyromonas sp. – were also identified, but their connection to UTI is unclear. Lactobacillus sp. – which are associated with a healthy flora in women – were found in urine cultures and often in smaller quantities which could suggest dysbiosis. More research on Lactobacillus sp. and their correlation with UTI is suggested for a more accurate indication of urinary dysbiosis in women.
190

Identification of human hair follicle antigens targeted in the presumptive autoimmune hair follicle disorder Alopecia Areata and their potential functional relevance In Vitro. Methods development for isolation and identification of Alopecia Areata-relevant human hair follicle antigens using a proteomics approach and their functional assessment using an Ex Vivo hair follicle organ culture model.

Leung, Man Ching January 2008 (has links)
Alopecia areata (AA) is a putative autoimmune hair loss disorder. It mainly affects the scalp hair but can also involve body hair, and can also affect the nail and the eye. While there are may be several lines of evidence to support the autoimmune basis of AA, there is still very little information on the hair follicle autoantigen(s) involved in its pathogenesis. In this project, serum antibodies (AA=10, control=10) were used to immunoprecipitate AA-relevant target antigens from normal human scalp hair follicle extracts. These immunoprecipitates were analysed by LC-MALDI-TOF/TOF mass spectrometry for target protein identification. This part of the project involved substantial methods development. Trichohyalin was immunoprecipitated by all AA sera, but by only 5 normal sera. Importantly, the mean Mascot scores of the AA group was significantly higher than the normal group (p=0.005). Keratin 16 was also identified from immunoprecipitates as another potential AA-relevant target antigen. Functional studies by ex vivo whole hair follicle organ culture using commercial antibodies to trichohyalin and keratin 16 significantly inhibited hair fibre elongation compared to controls. Indirect immunofluorescence studies revealed that AA sera contained higher immunoreactivity against normal human scalp anagen hair follicles compared to normal sera. Immunoreactivities were mainly in the outer root sheath and inner root sheath, and less so to the medulla and hair bulb matrix. Double immunofluorescence studies of AA and normal serum with anti-trichohyalin antibody (AE15) revealed co-localisation of 9 of the AA sera antibodies with trichohyalin in the inner root sheath (mostly in Henle¿s, less in Huxley¿s/inner root sheath cuticle), but only weakly in 3 normal sera. This study supports the involvement of an antibody response to anagen-specific hair follicles antigens in AA. Moreover, there may be some evidence that these antibodies may have a pathogenic role.

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