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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.
201

The extent of accessibility of public buildings to persons with disabilities in Kenya

Maigua, Mwaura Isaac January 2012 (has links)
Many countries in the world have in recent years developed measures to increase accessibility to the built environment for persons with disabilities. Of particular concern are facilities such as roads, railways and public premises. The United Nations Convention on the Rights of Persons With Disabilities (CRPD) confers accessibility as a right and gives responsibility to state parties to ensure to persons with disabilities (PWDs) a barrier free environment. The Constitution of Kenya (2010) states that PWDs have a right to facilities including educational that integrate their needs. The Person With Disabilities Act (2003) provides for mechanisms through which such enforcements can be enacted. The body responsible for implementing the Act has developed minimum accessibility guidelines to inform this endeavor as part of Kenya‟s dream of becoming a middle income economy by the year 2030. This research report/treatise details the findings of a pilot baseline survey study conducted in Nairobi, Kisumu and Mombasa Cities.
202

Language Translation for Mental Health Materials: A Comparison of Current Back-Translation and Skopostheorie-Based Methods

Black, Amelia Kathleen 01 March 2018 (has links)
As mental health professionals seek to disseminate information in many languages in order to meet the needs of an increasingly diverse population, it is important to consider the methods of written translation that the field is choosing to employ. The method chosen for translation can affect the accuracy and usability of the translated text. This study begins with a survey of current literature, the results of which suggest that the most popular translation method in the mental health field is back-translation, a translation method based in the premise that translating a text back into its original English after it has been translated into a second language provides an accurate indication of the success of the translation. This study then compares back-translation with an alternative translation approach based in skopostheorie, an area of translation theory that asserts that translational activity should be ultimately grounded in the purpose of the translation rather than the objective equivalency of the source and target texts. Each of the two approaches is applied separately in the translation of the Centers for Disease Control's handout, "Helping Parents Cope with Disaster," into Spanish and Chinese. The two resulting target texts for each language are compared in terms of linguistic equivalence by review committees and compared in terms of usability by individuals from the target audiences. Feedback from reviewers and audience members in both languages suggest that the skopostheorie based approach to translation may facilitate higher quality translation than back-translation in terms of both equivalence and usability. Suggestions for mental health professionals engaging in translation are then offered, as well as directions for future research.
203

Induced Pluripotent Stem Cell-derived Brain Endothelial Cells as a Cellular Model to Study Neisseria meningitidis Infection / Induziert pluripotente Stammzellen-basierte Hirnendothelzellen als zelluläres Modell zur Untersuchung der Infektion mit Neisseria meningitidis

Gomes, Sara Ferreira Martins January 2019 (has links) (PDF)
Bacterial meningitis occurs when blood-borne bacteria are able to penetrate highly specialized brain endothelial cells (BECs) and gain access to the meninges. Neisseria meningitidis (Nm) is a human-exclusive pathogen for which suitable in vitro models are severely lacking. Until recently, modeling BEC-Nm interactions has been almost exclusively limited to immortalized human cells that lack proper BEC phenotypes. Specifically, these in vitro models lack barrier properties, and continuous tight junctions. Alternatively, humanized mice have been used, but these must rely on known interactions and have limited translatability. This motivates the need to establish novel human-based in vitro BEC models that have barrier phenotypes to research Nm-BEC interactions. Recently, a human induced pluripotent stem cell (iPSC) model of BECs has been developed that possesses superior BEC phenotypes and closely mimics the in vivo blood vessels present at the blood-meningeal barrier. Here, iPSC-BECs were tested as a novel cellular model to study Nm-host pathogen interactions, with focus on host responses to Nm infection. Two wild type strains and three mutant strains of Nm were used to confirm that these followed similar phenotypes to previously described models. Importantly, the recruitment of the recently published pilus adhesin receptor CD147 underneath meningococcal microcolonies could be verified in iPSC-BECs. Nm was also observed to significantly increase the expression of pro-inflammatory and neutrophil-specific chemokines IL6, CXCL1, CXCL2, CXCL8, and CCL20, at distinct time points of infection, and the secretion of IFN γ and RANTES by iPSC-BECs. Nm was directly observed to disrupt tight junction proteins ZO-1, Occludin, and Claudin-5 at late time points of infection, which became frayed and/or discontinuous upon infection. This destruction is preceded by, and might be dependent on, SNAI1 activation (a transcriptional repressor of tight junction proteins). In accordance with tight junction loss, a sharp loss in trans-endothelial electrical resistance, and an increase in sodium fluorescein permeability was observed at late infection time points. Notably, bacterial transmigration correlated with junctional disruption, indicating that the paracellular route contributes for bacterial crossing of BECs. Finally, RNA-Sequencing (RNA-Seq) of sorted, infected iPSC-BECs was established through the use of fluorescence-activated cell sorting (FACS) techniques following infection. This allowed the detection of expression data of Nm-responsive host genes not previously described thus far to play a role during meningitidis. In conclusion, here the utility of iPSC-BECs in vitro to study Nm infection could be demonstrated. This is the first BEC in vitro model to express all major BEC tight junctions and to display high barrier potential. Altogether, here this model provides novel insights into Nm pathogenesis, including an impact of Nm on barrier properties and tight junction complexes and suggests that the paracellular route contributes to Nm traversal of BECs. / Eine bakterielle Meningitis tritt auf, wenn durch Blut übertragene Bakterien hochspezialisierte Hirnendothelzellen (BEC) durchdringen und Zugang zu den Meningen erhalten. Neisseria meningitidis (Nm) ist ein human-exklusiver Erreger, für dessen Untersuchung es an geeigneten In-vitro-Modellen mangelt. Bis vor kurzem war die Modellierung von BEC-Nm-Wechselwirkungen fast ausschließlich auf immortalisierte humane Zellen beschränkt, denen wichtige BEC-Phänotypen fehlen. Besonders hervorzuheben sind das Fehlen physiologischer Barriereeigenschaften durch unkontinuierliche dichte Zell-Zell-Verbindungen. Als alternative Modellorganismen können humanisierte Mäuse verwendet werden, die sich jedoch auf bekannte Wirt-Erreger-Wechselwirkungen stützen und durch Speziesunterschiede eine eingeschränkte Übersetzbarkeit aufweisen. Dies begründet die Notwendigkeit, neuartige humane In-vitro-BEC-Modelle zu etablieren, die physiologische Barrierephänotypen aufweisen, um Nm-BEC-Wechselwirkungen zu untersuchen. Kürzlich wurde ein humanes Modell entwickelt, welches auf aus induziert pluripotenten Stammzellen (iPSCs) abgeleiteten humanen BECs basiert und sich durch einen physiologischen Blut-Hirn-Schranken-Phänotyp auszeichnet. Die iPSC-BECs wurden in dieser Arbeit als neuartiges zelluläres Modell getestet, um Nm-Wirt-Pathogen-Wechselwirkungen zu untersuchen, wobei der Schwerpunkt auf Wirtsreaktionen auf Nm-Infektionen lag. Zwei Wildtypstämme und drei Mutantenstämme von Nm wurden verwendet, um zu bestätigen, dass diese ähnlichen Phänotypen wie in zuvor beschriebenen Modellen folgten. Hervorzuheben ist, dass die Rekrutierung des kürzlich veröffentlichten Pilus-Adhäsin-Rezeptors CD147 unter Meningokokken-Mikrokolonien in iPSC-BECs verifiziert werden konnte. Es wurde auch beobachtet, dass Nm die Expression der entzündungsfördernden und neutrophilen spezifischen Chemokine IL6, CXCL1, CXCL2, CXCL8 und CCL20 zu bestimmten Zeitpunkten der Infektion sowie die Sekretion von IFN-γ und RANTES durch iPSC-BECs signifikant erhöht. Es wurde zudem beobachtet, dass Nm die Tight Junction-Proteine ZO-1, Occludin und Claudin-5 zu späten Zeitpunkten der Infektion zerstört, verursacht durch die Infektion wurde ein ausgefranster und/oder diskontinuierlicher Tight Junction-Phänotyp beobachtet. Dieser Zerstörung geht die SNAI1-Aktivierung (ein Transkriptionsrepressor für Tight Junction-Proteine) voraus und könnte von ihr abhängig sein. In Übereinstimmung mit dem Verlust der Tight Junctions wurde zu späten Infektionszeitpunkten ein starker Verlust des transendothelialen elektrischen Widerstands und eine Zunahme der Natriumfluoreszein-Permeabilität beobachtet. Bemerkenswerterweise korrelierte die bakterielle Transmigration mit dem Verlust der Tight Junctions, was darauf hinweist, dass der parazelluläre Weg zur bakteriellen Überwindung von BECs eine entscheidende Rolle spielt. Schließlich wurde die RNA-Sequencing (RNA-Seq) von sortierten, infizierten iPSC-BECs durch die Verwendung von fluoreszenzaktivierten Zellsortiertechniken (FACS) nach der Infektion durchgeführt. Dies ermöglichte erstmalig den Nachweis von Expressionsdaten von Nm-responsiven Wirtsgenen, welche bei der Meningitidis eine Rolle zu spielen scheinen. Zusammenfassend konnte im Rahmen der vorliegenden Arbeit der Nutzen von iPSC-BECs In-Vitro-Modellen zur Untersuchung von Nm-Infektionen gezeigt werden. Dies ist das erste BEC-In-vitro-Modell, das alle wichtigen BEC-Tight Junctions exprimiert und ein hohes Barrierepotential aufweist. Insgesamt liefert das eingesetzte Modell neue Einblicke in die Nm-Pathogenese, einschließlich der Beeinflussung der Barriereeigenschaften und der Tight Junction-Komplexe durch Nm, und gibt erste Hinweise darauf, dass die parazelluläre Route zum Nm-Übertritt von BEC-Barrieren eine entscheidende Rolle spielt.
204

Hodnocení sfingosinu, dihydrosfingosinu a fytosfingosinu v modelech kožní bariéry / Study of sphingosine, dihydrosphingosine and phytosphingosine in skin barrier models

Kubátová, Denisa January 2021 (has links)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Denisa Kubátová Supervisor: PharmDr. Andrej Kováčik, Ph.D. Consultant: PharmDr. Lukáš Opálka, Ph.D. Title of diploma thesis: Study of sphingosine, dihydrosphingosine and phytosphingosine in skin barrier models The stratum corneum (SC), the uppermost layer of the skin, localized in the uppermost part of the epidermis, represents the skin barrier of the organism. SC is composed of corneocytes and an intercellular lipid matrix, which is formed by ceramides (Cer), free fatty acids (FFA), and cholesterol (Chol) in an equimolar ratio. Substances from the group of sphingolipids - Cer, are sphingoid bases (for example, sphingosine (S), dihydrosphingosine (dS), phytosphingosine (P)) acylated with a fatty acid (for example, lignoceric acid (LIG)). In the lipid matrix, the metabolic products of Cer (free sphingoid bases) are also present, but their role in SC barrier functions is not clear. Some studies show that Cer with different sphingoid bases, and increased presence of free sphingoid bases, can lead to a change in the permeability of the skin barrier. This work aimed to study the effect of permeability of sphingoid bases on the model membrane permeability. Nine types of membranes were prepared; they...
205

Short-term effects of selected barrier creams on skin barrier function / Amanda Vermaak

Vermaak, Amanda January 2014 (has links)
Background: Barrier creams are applied to the surface of the skin to form a barrier that aims to prevent the penetration of irritants and allergens through the skin surface. Several inconsistencies and controversies exist in literature regarding the effect that barrier creams may have on skin barrier function. Various skin surface parameters are used to evaluate the effect that the barrier creams have on skin barrier function. These parameters include transepidermal water loss (TEWL), skin hydration and skin surface pH. Total skin thickness may be assessed as a variable on its own. Differences may exist in skin surface parameters when comparing African participants with Caucasian participants. Aim: The specific aim of this research was to evaluate the short-term1 effects of selected barrier creams on skin barrier function. Note 1: The words short-term are used in this study as each barrier cream is only tested over a period of 8 hours and not tested over a long term period of months or years. Method: Forty two non-smoking participants were included and tested in this study, of which 21 were African and the rest Caucasian. TEWL, skin hydration and skin surface pH were used to evaluate the differences in the effect of two different barrier creams (Reinol Solvgard and Momar Chex) on skin barrier function. TEWL was measured by making use of a closed chamber Vapometer (Deflin Technology Ltd., Kuopio, Finland), skin hydration using a Corneometer® CM 825 and skin surface pH using a pH meter probe (Courage and Khazaka Electronic Kӧln, Germany). A micro-pipette was used to drip a standard volume of 20 μl of ultrapure water on the skin surface before the researcher placed the pH meter probe onto the skin surface. Total skin thickness was measured by making use of ultrasound (Ultrascan 22 - TBS0061B) (Courage and Khazaka Electronic Kӧln, Germany). Three consecutive measurements were taken on the mid-forearm and the palm of the experimental arm. After baseline values were measured, 5 ml of the selected barrier cream was applied to the experimental arm. The barrier cream (selected for the day) was reapplied after 2, 4 and 6 hours and measurements were taken every 2, 4, 6 and 8 hours. The total skin thickness was measured at time zero and at 8 hours. Results: TEWL: For both barrier creams, statistical significant differences (p ≤ 0.05) were found between TEWL on the palms of African participants and Caucasian participants. Skin hydration: Statistically significant differences (p ≤ 0.05) were obtained with regard to mid-forearm skin hydration when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). A statistically significant difference (p ≤ 0.05) was obtained with regard to mid-forearm skin hydration when comparing African participants with Caucasian participants (this was only applicable to Reinol Solvgard). Statistical significant differences (p ≤ 0.05) were obtained with regard to skin hydration palm when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). Statistically significant differences (p ≤ 0.05) were obtained with regards to skin hydration palm when comparing African participants with Caucasian participants (this was applicable to both barrier creams). Skin surface pH: A statistically significant difference (p ≤ 0.05) was obtained with regard to pH of the mid-forearm when comparing Reinol Solvgard with Momar Chex (this was applicable to only the African participants). A statistical significance (p ≤ 0.05) was obtained with regards to skin surface pH mid-forearm when comparing African participants with Caucasian participants (this was applicable to Momar Chex barrier cream only). A statistically significant difference (p ≤ 0.05) was obtained with regards to the pH of the palm when comparing Reinol Solvgard with Momar Chex (this was only applicable to the African racial group). Conclusion: Using skin surface parameters, it can be concluded that Momar Chex barrier cream elicited more positive effects on skin barrier function than Reinol Solvgard barrier cream. This may be ascribed to the fact that both barrier creams lowered TEWL (positive effect), Reinol Solvgard lowered skin hydration (negative effect) whereas, Momar Chex increased the skin hydration (positive effect) and both barrier creams increased skin surface pH (negative effect). Furthermore, the objectives of this study were reached as (a) short-term effects on skin surface parameters were identified between African versus Caucasian participants, (b) significances were observed between the two barrier creams (Momar Chex and Reinol Solvgard) by making use of skin surface parameters and (c) general increases and or decreases were observed in skin surface parameters over a short term period of 8 hours. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2015
206

Short-term effects of selected barrier creams on skin barrier function / Amanda Vermaak

Vermaak, Amanda January 2014 (has links)
Background: Barrier creams are applied to the surface of the skin to form a barrier that aims to prevent the penetration of irritants and allergens through the skin surface. Several inconsistencies and controversies exist in literature regarding the effect that barrier creams may have on skin barrier function. Various skin surface parameters are used to evaluate the effect that the barrier creams have on skin barrier function. These parameters include transepidermal water loss (TEWL), skin hydration and skin surface pH. Total skin thickness may be assessed as a variable on its own. Differences may exist in skin surface parameters when comparing African participants with Caucasian participants. Aim: The specific aim of this research was to evaluate the short-term1 effects of selected barrier creams on skin barrier function. Note 1: The words short-term are used in this study as each barrier cream is only tested over a period of 8 hours and not tested over a long term period of months or years. Method: Forty two non-smoking participants were included and tested in this study, of which 21 were African and the rest Caucasian. TEWL, skin hydration and skin surface pH were used to evaluate the differences in the effect of two different barrier creams (Reinol Solvgard and Momar Chex) on skin barrier function. TEWL was measured by making use of a closed chamber Vapometer (Deflin Technology Ltd., Kuopio, Finland), skin hydration using a Corneometer® CM 825 and skin surface pH using a pH meter probe (Courage and Khazaka Electronic Kӧln, Germany). A micro-pipette was used to drip a standard volume of 20 μl of ultrapure water on the skin surface before the researcher placed the pH meter probe onto the skin surface. Total skin thickness was measured by making use of ultrasound (Ultrascan 22 - TBS0061B) (Courage and Khazaka Electronic Kӧln, Germany). Three consecutive measurements were taken on the mid-forearm and the palm of the experimental arm. After baseline values were measured, 5 ml of the selected barrier cream was applied to the experimental arm. The barrier cream (selected for the day) was reapplied after 2, 4 and 6 hours and measurements were taken every 2, 4, 6 and 8 hours. The total skin thickness was measured at time zero and at 8 hours. Results: TEWL: For both barrier creams, statistical significant differences (p ≤ 0.05) were found between TEWL on the palms of African participants and Caucasian participants. Skin hydration: Statistically significant differences (p ≤ 0.05) were obtained with regard to mid-forearm skin hydration when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). A statistically significant difference (p ≤ 0.05) was obtained with regard to mid-forearm skin hydration when comparing African participants with Caucasian participants (this was only applicable to Reinol Solvgard). Statistical significant differences (p ≤ 0.05) were obtained with regard to skin hydration palm when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). Statistically significant differences (p ≤ 0.05) were obtained with regards to skin hydration palm when comparing African participants with Caucasian participants (this was applicable to both barrier creams). Skin surface pH: A statistically significant difference (p ≤ 0.05) was obtained with regard to pH of the mid-forearm when comparing Reinol Solvgard with Momar Chex (this was applicable to only the African participants). A statistical significance (p ≤ 0.05) was obtained with regards to skin surface pH mid-forearm when comparing African participants with Caucasian participants (this was applicable to Momar Chex barrier cream only). A statistically significant difference (p ≤ 0.05) was obtained with regards to the pH of the palm when comparing Reinol Solvgard with Momar Chex (this was only applicable to the African racial group). Conclusion: Using skin surface parameters, it can be concluded that Momar Chex barrier cream elicited more positive effects on skin barrier function than Reinol Solvgard barrier cream. This may be ascribed to the fact that both barrier creams lowered TEWL (positive effect), Reinol Solvgard lowered skin hydration (negative effect) whereas, Momar Chex increased the skin hydration (positive effect) and both barrier creams increased skin surface pH (negative effect). Furthermore, the objectives of this study were reached as (a) short-term effects on skin surface parameters were identified between African versus Caucasian participants, (b) significances were observed between the two barrier creams (Momar Chex and Reinol Solvgard) by making use of skin surface parameters and (c) general increases and or decreases were observed in skin surface parameters over a short term period of 8 hours. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2015
207

ADA Compliance and Accessibility of Aquatic Facilities in the North Texas Area

Pike, Hilary Eryn 05 1900 (has links)
The purpose of this study was to determine the degree to which existing aquatic facilities in the North Texas metroplex complied with the 1991 Americans with Disabilities Act Accessibility Guidelines (ADAAG) and the proposed Americans with Disabilities Act Accessibility Guidelines: Recreation Facilities (ADAAG supplement). Fifty-two aquatic facilities were evaluated based on: parking lot, ticket counter, gate/entry, restroom, dressing area, drinking fountain, pathway, and pool entry method structural domains. Physical measurements and a few direct observations were recorded on the survey instrument. Surveys were then reviewed and facility scores were tabulated. No facility was found to be 100% compliant with ADAAG and the ADAAG supplement. Aquatic facilities are already struggling to catch up with the 1991 ADAAG, but when the United States Department of Justice approves the proposed ADAAG supplement, aquatic facilities will fall even further behind.
208

Surface modification of paper and cellulose using plasma enhanced chemical vapor deposition employing fluorocarbon precursors

Vaswani, Sudeep 18 January 2005 (has links)
Paper and cellulosic materials hold a good promise of being candidates for flexible packaging materials provided suitable barrier properties such as water repellence and grease resistance are imparted to them. One of the methods to achieve these objectives is to surface modify paper/cellulose by applying thin fluorocarbon coatings on the surface. Fluorocarbon thin films produced by plasma enhanced chemical vapor deposition (PECVD) offer several advantages over the films produced by conventional polymerization means. Plasma deposited films are pinhole-free, chemically inert, insoluble, mechanically tough, thermally stable and highly coherent and adherent to variety of substrates. In this work, we investigate the use of PECVD technique to produce barrier films on paper and cellulosic materials. These films, with composition and properties not much different from PTFE, repel water and act as a good barrier to lipophilic materials. Two different monomers, pentafluoroethane (PFE; CF3CHF2) and octafluorocyclobutane (OFCB; C4F8), were investigated and compared in terms of deposition rates and final film properties. Various analytical techniques (XPS, FT-IR, SEM, Ellipsometry, Contact Angle Goniometry, etc.) were used to characterize the fluorocarbon films. The fluorocarbon coated paper exhibited hydrophobic character as evidenced by high water contact angles. Although the films allow water vapor diffusion, the films are hydrophobic and are not wetted when liquid water contacts these layers. Based on various thickness of these films deposited on surface of cellulose, there was a minimum PFE film thickness required to achieve a stable hydrophobic behavior. The fluorocarbon films investigated in this work also exhibited good resistance to lipophilic materials (e.g. oils, fatty acids, etc.). While techniques such as oleic acid penetration and TAPPI "oil-kit" test are commonly used in paper industry to qualitatively test the grease barrier properties of paper/cellulose, this work attempts to quantify the grease barrier properties of fluorocarbon coated paper using techniques such as magnetic resonance imaging (MRI) and quartz crystal microbalance (QCM). Finally, the feasibility of deposition of dual layer films by PECVD was investigated using PFE and n-isopropylacrylamide (NIPAAM) as precursors for applications in barrier packaging and printing.
209

Investigating the molecular mechanism of replication restart in fission yeast

Nguyen, Michael Ong January 2014 (has links)
Successful replication of the genome during each cell cycle requires that every replication fork merge with its opposing fork. However, lesions in the template DNA or protein-DNA barriers often impede replication forks and threaten the timely completion of genome duplication. If a fork encounters a replication fork barrier (RFB), it can be subject to a variety of fates. In some cases the replisome is maintained in a manner such that it can resume DNA synthesis when the barrier is removed. Alternatively the stalled fork is simply held in a competent state to merge with the opposing fork when it arrives. However, fork stalling can also precipitate dissociation of the replisome (fork collapse) or even fork breakage. If this happens the recombination machinery can intervene to restore DNA integrity and restart replication, albeit with a risk of causing deleterious genetic change if ectopic homologous sequences are recombined. I have exploited a site-specific RFB in fission yeast termed RTS1 to investigate the consequences of perturbing a single replication fork. RTS1 is a polar RFB (i.e. it blocks fork progression in a unidirectional fashion), enabling replication to be completed by the opposing fork. Despite this, fork blockage at RTS1 triggers a strong recombinational response that is able to restart DNA synthesis, which at least initially is highly error prone. Here, I present my work in establishing a live cell imaging approach to visualizing the recombinational response at the RTS1 RFB, demonstrating that the majority of cells initiate recombination-dependent replication (RDR). RDR begins within a few minutes of fork blockage and is only curtailed by the arrival of the opposing fork. It depends on the Rad52 protein, which remains associated with the restarted fork and whose presence correlates with its infidelity. I also illustrate the significance of various genetic factors, including Rad51, the Rad51 mediators, Fml1 helicase, Rad54 translocase, Pfh1 sweepase, and Cds1 checkpoint kinase, in modulating Rad52 localization and block-induced recombination at the RTS1 RFB.
210

Evaluation of biomarkers for testicular toxicity

Elkin, Naomi D. January 2010 (has links)
Non-clinical safety assessment is essential during the drug development process in the pharmaceutical industry, and involves numerous, detailed in vitro and in vivo toxicology tests (general, reproductive and genetic), and safety pharmacology studies. The testis is a common organ for adverse drug effects leading to attrition of potential compounds. It would, therefore, be useful to detect testicular toxicity as early as possible in the drug development process. Histopathology is the standard method for assessing testis toxicity, but a biomarker for ‘early warning’ detection of testicular toxicity would be far more useful in non-clinical toxicology studies. The aim of this thesis was to evaluate the feasibility of this approach. It is thought that proteins can leak from seminiferous tubules into testicular interstitial fluid following testicular damage, due to either loss of integrity of the blood-testis barrier (BTB) or germ cell damage. A potential biomarker protein could, therefore, leak out of seminiferous tubules into interstitial fluid and then into blood following toxicological insult to the testis. A suitable biomarker protein must be testis specific, abundant, and not normally be present in blood. It may also need to have a low molecular weight. To investigate if proteins do leak out of seminiferous tubules following testicular damage, three known testicular toxicants which affect different aspects of the testis were used; cadmium chloride causes disruption to the blood-testis barrier and spermatogenesis, methoxyacetic acid (MAA) specifically causes a loss of pachytene spermatocytes, and 1,3-dinitrobenzene (DNB) causes Sertoli cell vacuolation and subsequent germ cell disruption. Adult male Wistar rats were treated with various doses of these toxicants to give mild and moderate responses. Samples were collected 24 hours later. Testicular damage was investigated by immunohistochemistry for well-known germ cell markers (DAZL, VASA) and using a general antibody to seminiferous tubule proteins. The integrity of the BTB was evaluated using immunofluorescent co-localisation of occludin, ZO-1, claudin-11, N-cadherin and β-catenin, and a biotin tracer. Protein leakage was investigated using analysis of interstitial fluid samples by 1D gel electrophoresis and staining with Coomassie-based dye or Western blotting for germ cell proteins and with the general antibody to seminiferous tubule proteins. Protein leakage from seminiferous tubules into interstitial fluid was observed with high dose cadmium chloride treatment. This was coincident with a loss of integrity of the BTB. No leakage was observed with MAA treatment which caused a specific loss of pachytene spermatocytes, or DNB which caused Sertoli cell vacuolation. With both treatments the BTB did not appear to be damaged suggesting that protein leakage occurs only following loss of integrity of the BTB. This was further investigated using treatments reported to specifically disrupt the BTB, namely intra-testicular administration of glycerol or transforming growth factor-β3, with samples collected 48 hours later. The damage caused was very localised, although BTB disruption with glycerol treatment caused some protein leakage. The presence of germ cell proteins in interstitial fluid samples before and after the development of the BTB during normal development was also evaluated, although most proteins of interest were not expressed in germ cells of the immature testis before BTB formation. Finally, five potential biomarker candidate proteins (ADAM3, Calpastatin, DAZL, FABP9, VASA) were selected and investigated using samples from the testicular toxicant studies. Smaller molecular weight proteins were thought to be more likely to leak out of seminiferous tubules, however, VASA, a large molecular protein (76kDa) was shown to leak into interstitial fluid following high dose cadmium chloride treatment. However, FABP9 (low molecular weight) was found to be the most promising biomarker for loss of BTB integrity. The results suggest that a biomarker could only be detected if there is a loss of integrity of the BTB and severe disruption of spermatogenesis, thus conferring no real advantage over present histopathology-based toxicity evaluations. Therefore, an automated immunohistochemistry and image analysis method was investigated as a refined method for detection of testicular toxicity at the end of a toxicology study, and shown to have promise.

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