Indoor air quality is described as the chemical, physical and biological characteristics of air in a residential or occupational indoor environment. In residential settings, there are many contributions to indoor pollution levels namely; human activities, biological sources and outdoor air. There has been increased focus on house dust due to its potential to contain biological and chemical pollutants in indoor environments. These have the potential to cause harm to human health. The purpose of this study was to conduct toxicological analysis of house dust collected from inside selected Durban residential buildings. The objectives of this study were to isolate, identify and quantify mould occurrence in house dust samples; to measure the occurrence of heavy metals (arsenic, lead and mercury) in house dust; and to analyse the cytotoxicity of house dust on human lung bronchus carcinoma epithelial line (A549) and human lung bronchus virus transformed epithelial cell line (BBM). One hundred and five house dust samples were obtained from households that participated in the South Durban Health Study. In each home, a sample of settled dust was collected, using standardized protocols, then sieved and individually packed into polystyrene bags. The samples were taken from three surface areas namely; living room couches, bed mattresses, and carpets. Well documented methods were used for the isolation, identification and quantification of mould. The samples for heavy metals analysis were sent to Umgeni Water (chemistry laboratory, Pietermaritzburg) where standardised methods were used. Human cell lines were treated with five different dilutions of each house dust extract. Cell viability was assessed using the MTT assay. Toxic effects of house dust extract were analyzed, following house dust extract treatment and cells were stained with double dye (annexin-V- and propidium iodide) and analysed with flow cytometry, and fluorescent microscope. Cytokines were analysed by Microbionix (Neuried, German) using a Luminex®100 plate reader for multiplex human cytokines analysis. There were (n=128) mould types isolated and (n=105) were identified, of which (n=10) were predominately isolated moulds. This was further confirmed by Allerton Provincial Laboratory in Pietermaritzburg. Among the isolated genera in all three surface areas, Rhizopus spp and Penicillium spp were widely distributed throughout surface areas in greater proportion. The overall highest mean which was reported in this study and expressed in colony forming unit per gram (CFU/g) for Penicillium spp ranged (3400 - 62316 CFU/g) obtained from living room couches, followed by Rhizopus spp (5200 - 15990 CFU/g). The mould results were compared with the South African Occupational Health and Safety Act (OHSA) 85 of 1993 as amended suggested guidelines of 1,000, 000 CFU/g. The findings of this study suggest the moulds in the homes studied were below the suggested guideline. However, this does not imply that the indoor conditions are unsafe or hazardous. Instead, the findings act as an indicator of moulds presence indoors. The type of airborne mould, its concentration and extent of exposure and the health status of the occupants of a building will determine the health effects on an individual. Heavy metals were detected in the dust in the following ascending order: arsenic (As) ranged from 1.3 ug/g -18.4 ug/g (mean, 4.26 ug/g), lead (Pb) ranged from 28.0 - 872 ug/g (mean 171.66 ug/g), and mercury (Hg) ranged from 0.6 -19.0 ug/g (mean, 2.22 ug/g). The mean concentration of lead in the dust was within the range of Canadian National Classification guidelines on residential contamination (500 ug/g). There was numerous numbers of samples in this study that exceeded these guidelines. The mean concentration of arsenic was within residential soil guidelines (20 ug/g). Mercury was within limits when compared with Global Hg project guidelines of soil/residential (6.6 ug/g), thought some of samples were notably above this mean. The ability of house dust extract to lower the cell viability which was slightly above 80% (prior treatment) to less than 50% (post treatment) in both cells was observed in this study. The findings in this study showed that dust extract are toxic to human cell lines, and cells undergone a degree of apoptosis and necrosis 62% (A549) and 99% (BBM). The cytokines serve an important role in the non-specific defence external against insults. It was observed that A549 cells up-regulated the release of IL-6 and IL-8 pro-inflammatory cytokines and under-regulated the release of other cytokines analysed (IL-4, IL-13, and TNF-a). BBM cells released IL-4, IL-8 and IL-13 within limit of detection. The presence of moulds in these sampled indoor household dusts, which is comparable with findings elsewhere indoors, show that moulds act as an indicator for building conditions such as dampness, which supports mould growth. Individuals, whether they are sensitized or not, may develop allergic reactions towards spores, thus the elevated numbers of spores quantified in this study are of concern. Some of the heavy metals reported in this study were higher or marginally higher than international norms and guidelines. The findings in this study strongly suggest that house dust extract is toxic to human lung cell lines. It must be noted, however, that this study may not reflect all that happens when a human lung is exposed to house dust. The findings of this study could contribute to the development of South African indoor air guidelines. In conclusion further study needed to be undertaken with respect to air pollution disease such as allergic; the reason being this study shown the reduced expression of cytokines that are involved in allergic inflammation. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2009.

Les effets anti-allergiques des bactéries lactiques sont suggérés par plusieurs études épidémiologiques, des essais cliniques et des modèles expérimentaux d’allergie. Cependant, les propriétés immunomodulatrices des bactéries lactiques sont sous-exploitées par les stratégies vaccinales développées pour combattre l’allergie et les mécanismes empruntés par ces bactéries pour moduler l’allergie restent peu caractérisés.<p>Dès lors, nous avons caractérisé les propriétés immunomodulatrices qu’exerce Lactobacillus plantarum NCIMB8826, une bactérie lactique modèle, sur la cellule dendritique étant donné le rôle déterminant de cette cellule sur la réponse allergique. Nous montrons que L. plantarum induit une forte sécrétion d’IL-12 p40, d’IL-12 p70, de TNF-a mais une faible production d’IL-10. Cette faculté à induire la sécrétion de cytokines polarisantes dépend de TLR2, de TLR9, de MyD88, de NF-kB, des MAPKs (en particulier JNK, p38 et ERK 1/2), de la composition de l’acide lipotéichoïque de L. plantarum et de CD14. Nous montrons aussi que l’ADN génomique de L. plantarum est un agoniste de TLR9 et que CD14 et CD36 facilitent la liaison de la cellule dendritique avec L. plantarum.<p>Ensuite, nous avons évalué le potentiel vaccinal d’une coadministration L. plantarum + Der p 1 dans un modèle murin d’allergie à Der p 1. Cette formulation vaccinale prévient la production d’IgE Der p 1-spécifique et atténue l’éosinophilie pulmonaire tout en stimulant une forte production d’anticorps IgG2a Der p 1-spécifiques et d’IFN-g par les cellules spléniques. Ces effets bénéfiques nous ont conduit à élaborer une bactérie lactique recombinante dérivée de L. plantarum produisant Der p 1 pour la vaccination contre l’allergie aux acariens. La forme antigénique que nous avons réussi à faire produire par L. plantarum correspond à une protéine de fusion entre la Maltose Binding Protein de E. coli et ProDer p 1 (le zymogène de Der p 1), la présence de ce partenaire de fusion étant indispensable à la production de ProDer p 1. En prophylaxie, la vaccination par cette bactérie recombinante prévient la production d’anticorps IgE-Der p 1-spécifiques et stimule la production d’anticorps IgG2a spécifiques, reproduisant les effets de la coadministration L. plantarum + Der p 1. Elle réduit de manière drastique la production d’IL-5 des cellules spléniques et des cellules ganglionnaires médiastinales et prévient l’éosinophilie pulmonaire mais n’a pas d’effet sur l’hyperréactivité bronchique. Der p 1 étant un des allergènes d’acarien les plus immunodominants, cet ensemble de données montre donc que cette bactérie recombinante constitue un vaccin prophylactique prometteur pour la prévention de l’allergie aux acariens. Des résultats préliminaires obtenus à partir de cellules dendritiques humaines et lymphocytes T autologues montrent la forte capacité de cette bactérie recombinante à induire le développement d’une réponse Th1 fortement polarisée (production d’IFN-g en l’absence de production d’IL-4 et d’IL-5), ce qui suggère que l’utilisation de cette bactérie recombinante pourrait être envisagée pour le traitement de l’allergie chez l’homme. <p> / Doctorat en Sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished

Notre volonté d'économiser l'énergie nous pousse à vivre dans un environnement confiné favorisant les acariens et les micro-organismes. L'objectif de la thèse est de caractériser la contamination en acariens et en micro-organismes des logements de patients présentant des pathologies respiratoires, d'évaluer l'influence des interactions acariens/moisissures sur l'exposition aux allergènes et de comprendre les facteurs favorisant la pollution biologique de l'air intérieur. Afin de disposer d'un outil commun aux acariens et aux micro-organismes, un modèle innovant de quantification des acariens pas qPCR a été mis au point. Les acariens de stockage sont sous-estimés et les mesures d'éviction doivent être appliquées à l'ensemble de l'habitat. L'observation des interactions acariens/moisissures a montré une vraie relation symbiotique: dispersion des moisissures et apports des nutriments essentiels aux acariens. La contamination des logements de producteurs laitiers atteint de BPCO a été comparée à celle de producteurs laitiers sains, de patients BPCO non­-agriculteurs et de sujets sains non-agriculteurs. L'exposition agricole est abondante et spécifique à certains micro­organismes caractéristiques de la ferme et la sensibilité IgG à Wallemia sebi est spécifique des producteurs laitiers BPCO Le suivi de l'impact du compostage sur la qualité biologique de l'air intérieur a démontré une augmentation des concentrations en acariens de stockage et certaines moisissures circonscrite au bio-seau. De nouveaux indicateurs communs aux acariens, aux moisissures et aux bactéries devraient nous permettre de progresser dans la détermination de la relation dose/effet. / Our will to save energy leads us to live in a confined environment providing the ideal conditions to mites and microorganisms development. The aim of the thesis is to characterize mites and microorganisms contamination of dwellings from patients suffering respiratory diseases, to estimate the influence of the interactions between various organic communities on the allergens exposure and to understand the factors increasing the biological pollution ofindoor air. To evaluate our exposition, we needed to quantify mites and microorganisms with a common tool and an innovative quantification mode! of domestic mites by qPCR was developed. The presence of storage mites is overemphasized in dwellings of allergie patients and the eviction measures of mites should be applied into any rooms of dwellings. The contamination of dairy fanners' dwellings suffering from COPD was compared with that ofhealthy dairy fanners, COPC patients non-farmers and healthy non-fanners. In dwellings, the dairy fanners' exposure was important and specific ofth1 fanning environment. The lgG sensitivity to Wallemia sebi was significantly specific of dairy fanners suffering from COPD. The impact of the composting on the biological air quality was evaluated and the concentrations in storage mites and some molds increased significantly only in a confined area around the waste bin. New common indicators of domestic mites, molds and bacteria should allow us to progress in the determination of the dose-response relationship for the different allergens and their possible synergie effects.

<p>Infant exposure to the microbial and allergenic content of indoor floor dust has been shown to play a significant role in both the development of, and protection against, allergies and asthma later in life. Resuspension of floor dust during infant locomotion induces a vertical transport of particles to the breathing zone, leading to inhalation exposure to a concentrated cloud of coarse (> 1μm) and fine (≤ 1μm) particles. Resuspension, and subsequent exposure, during periods of active infant locomotion is likely influenced by gait parameters. This dependence has been little explored to date and may play a significant role in floor dust resuspension and exposure associated with forms of locomotion specific to infants. This study explores associations between infant locomotion dynamics and floor dust resuspension and exposure in the indoor environment. Infant gait parameters for walking and physiological characteristics expected to influence dust resuspension and exposure were identified, including: contact frequency (steps min^-1), contact area per step (m²), locomotion speed (m s^-1), breathing zone height (cm), and time-resolved locomotion profiles. Gait parameter datasets for standard gait experiments were collected for infants in three age groups: 12, 15, and 19 months-old (m/o). The gait parameters were integrated with an indoor dust resuspension model through a Monte Carlo framework to predict how age-dependent variations in locomotion affect the resuspension mass emission rate (mg h^-1) for five particle size fractions from 0.3 to 10 μm. Eddy diffusivity coefficients (m² s^-1) were estimated for each age group and used in a particle transport model to determine the vertical particle concentration profile above the floor.</p><p>Probability density functions of contact frequency, contact area, locomotion speed, breathing zone height, and size-resolved resuspension mass emission rates were determined for infants in each group. Infant standard gait contact frequencies were generally in the range of 100 to 300 steps min^-1and increased with age, with median values of 186 steps min^-1for 12 m/o, 207 steps min^-1 for 15 m/o, and 246.2 steps min^-1 for 19 m/o infants. Similarly, locomotion speed increased with age, from 67.3 cm s^-1at 12 m/o to 118.83 cm s^-1 at 19 m/o, as did the breathing zone height, which varied between 60 and 85 cm. Resuspension mass emission rates increased with both infant age and particle size. A 19 m/o infant will resuspend comparably more particles from the same indoor settled dust deposit compared to a 15 m/o or 12 m/o infant. Age-dependent variations in the resuspension mass emission rate and eddy diffusivity coefficient drove changes in the vertical particle concentration profile within the resuspended particle cloud. For all particle size fractions, there is an average of a 6% increase in the resuspended particle concentration at a height of 1 m from the floor for a 19 m/o compared to a 12 m/o infant. Time-resolved locomotion profiles were obtained for infants in natural gait during free play establish the transient nature of walking-induced particle resuspension and associated exposures for infants, with variable periods of active locomotion, no motion, and impulsive falls. This study demonstrates that floor dust resuspension and exposure can be influenced by the nature of infant locomotion patterns, which vary with age and are distinctly different from those for adults.</p>

<p>Asthma involves a systemic element that includes the mobilization and lung-accumulation of bone marrow-derived endothelial progenitor cells (EPC). This traffic may be driven by the stromal cell derived factor-1α (SDF-1α)/CXCR4 axis, where SDF1-α is a potent progenitor cell chemoattractant.</p> <p>Interfering with EPC lung-accumulation by administering AMD3100, a CXCR4 antagonist, was previously shown to be associated with the modulation of airway angiogenesis and airway hyperresponsiveness. However, since eosinophils express CXCR4, it is unknown whether AMD3100 acted directly on EPC or indirectly through its anti-inflammatory effects on eosinophils.</p> <p>We investigated the role that eosinophilic inflammation plays in the lung-homing of EPCs and airway angiogenesis in allergic asthmatic response by utilizing eosinophil deficient (PHIL) mice.</p> <p>Wild-type BALB/c (WT) and PHIL mice underwent a chronic house dust mite (HDM) exposure protocol. Treatment groups were administered AMD3100. Outcome measurements were made 24hrs post final exposure and included: flow cytometry to enumerate lung-extracted EPCs, immunostaining for von Willebrand factor to assess bronchial vascularity, bronchoalveolar lavage for airway inflammation, haematoxylin and eosin stain to enumerate eosinophils, picrosirius red stain to assess collagen deposition, and measurement of airway resistance to increasing intranasal doses of methacholine.</p> <p>HDM exposed mice had a significant increase in EPC lung accumulation, bronchial vascularity, airway inflammation, collagen deposition and airway hyperresponsiveness (AHR) in both WT and PHIL groups, with some indices at lower levels in PHIL mice. Concurrent treatment with AMD3100 significantly attenuated EPC lung homing, bronchial vascularity, eosinophil numbers in lung tissue and AHR, but not collagen deposition in WT mice. AMD3100 treatment significantly attenuated all indices in PHIL mice.</p> <p>The findings of this study show that, EPC-driven angiogenesis and the development of AHR in allergic airway responses are independent of eosinophils, the presence of these cells, however, may have a role in worsening of the pathology of allergic airways disease.</p> / Master of Science (MSc)