Dissertationen zum Thema „Respiratory organs Diseases Immunological aspects“

To investigate the possibility that malnutrition is an important factor that prolongs respiratory failure (PRF), I studied the effects of pharmacologic injections of recombinant human growth hormone (rhGH), an important anabolic stimulus, on nutritional and respiratory parameters in patients requiring mechanical ventilation for more than three days. Patients were excluded from consideration if dominating factors known to prolong ventilatory failure had not been stabilized. Over ten months, 106 patients in PRF were evaluated, but only six met the selection criteria. Three patients were randomized to receive standard nutritional support, and three into a group that received the equivalent nutrition plus 5 mg/day of rhGH for 14 days or until withdrawal of mechanical ventilation. Baseline characteristics of the selected patients were divergent as demonstrated by body mass indexes ranging from 14 to 42 (kg/m$ sp2),$ baseline maximal inspiratory pressures (PI$ sb{ max}$ from $-$15 to $-$70 cm H$ sb2$O, and Day 1 N balances from $-$13.5 to 1.2 g N/day. Despite increased plasma insulin-like growth factor-1 concentrations, the mean daily N balances of the rhGH-treated group were no better than the controls (1.3 $ pm$ 5.0 vs. 0.4 $ pm$ 2.6 g N/day; Mean $ pm$ SD), nor were there differences in PI$ sb{ max},$ level of ventilatory assistance required, and days to weaning. The persistence of respiratory failure in the overwhelming majority of patients in PRF appears to be due to factors already known to prevent weaning from mechanical ventilation. Even the carefully selected patients enrolled in the present study were insufficiently homogeneous or stable enough to allow proper testing of the experimental hypothesis.

Objectives : To investigate the impacts of traffic related air pollution (TRAP) on children’s respiratory health, and to investigate the policies and regulations implemented in other countries and the suggestions from the World Health Organization (WHO) to tackle this problem. Methods and Results: Using relevant keywords, 122 articles were acquired from PubMed and 15 were from MEDLINE via EBSCO host respectively. The articles were published between 1980 to 2013; all of which had examined the impacts of TRAP on children’s respiratory health. After assessing inclusion and exclusion criteria, 9 articles were finally included in this systematic review. Differences in demographic characteristics were studied and compared to determine the association between TRAP exposure and respiratory health impacts on children aged between 1 and 18. Four cross-section surveys and five cohort studies were selected in this review. The association between TRAP exposure and differences in children’s respiratory impacts were demonstrated in all studies. Multiple outcome measures were used to examine changes of children’s respiratory health such as the decline in lung function, incidences of asthma and inflammatory responses. There were 4 out of 9 articles suggesting the decline in lung function was related to TRAP exposure; 5 out of 9 articles showed the relationships between incidences of asthma and inflammatory responses and TRAP exposure and 2 articles mentioned other respiratory symptoms; notably, wheezing and sneezing, runny and stuffed nose. This review finally summarized the results of selected articles stressing that children who lived close to roadway within a 500 meter radius from home, with an early exposure to air pollution in the first year of age and a frequent exposure to heavy road traffic and outdoor air pollutants would experience greater impacts on respiratory health. Conclusion: The positive association between the impacts on children’s respiratory health and TRAP exposure has been determined through this systematic review. Stricter emission control strategies and updated guidelines are required to regulate traffic emission and improve air quality in order to reduce harm and provide a better living environment for our next generations.
published_or_final_version
Public Health
Master
Master of Public Health

Artists are exposed to numerous respiratory health hazards in the production of art. Little is known of artists' studio behaviors or of their health beliefs related to respiratory toxins. The Health Belief Model hypothesizes that individuals require a minimal level of relevant health motivation and knowledge before attempting to prevent a health condition, as well as a perception of their vulnerability to health conditions they view as threatening, conviction in the efficacy of preventive behaviors, and a perception that recommended preventive action entails few difficulties. This descriptive and exploratory study, conducted within the framework of the Health Belief Model, seeks to determine artists' knowledge, health beliefs, and preventive studio practices related to occupational respiratory health risks.

Thesis (MNutr)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Background: The Ironman® triathlon is an ultra-endurance event. It has previously been shown that heavy training schedules and racing ultra-endurance events can lead to immune impairment. Evidence supporting the potential role of dietary intake and body composition on immune impairment or upper respiratory tract infections (URTIs) is currently lacking. Aim: To investigate the relationship between dietary intake, body composition and the incidence of URTI in triathletes residing in Port Elizabeth (PE), during training and competition for the Ironman® 2011 triathlon. Method: An observational longitudinal descriptive study with an analytical component was conducted. The study population included triathletes living in PE, who completed an Ironman® distance event one year prior to, and who were training for the April 2011 Ironman®. Habitual dietary intake was assessed with a quantitative food frequency questionnaire; and race dietary strategies with a three day food record. Body composition was determined with anthropometry and the incidence of URTI was assessed with the WURSS-44. A general health screen (SF-36) was also administered. Results: Habitual dietary intake during the three months pre- and post-Ironman® 2011 triathlon was adequate for all nutrients except for carbohydrate intake in female and male participants (pre-Ironman® of 4.0 (1.7) g/kg body weight (BW)/day and 5.4 (1.8) g/kg BW/day; and post-Ironman® 3.0 (1.0) g/kg BW/day and 4.7 (1.5) g/kg BW/day respectively). Carbohydrate-loading strategies were below recommendations with intakes of 6.0 (2.9) and 5.1 (2.5) g/kg BW/day for female and male participants respectively. Race day nutrition strategies were below recommendations for carbohydrate intake. Post-race dietary intake was below recommendations for carbohydrate in the female participants (0.9 (0.5) g/kg BW). Body mass index was 26.6 (3.4) kg/m2 and 26.1 kg/m2 (1.40) for female and male study participants respectively. Body fat percentage was at the upper end for endurance athletes (29.3 (9.4) % and 13.7 (5.1) % for females and males respectively). In this study 25 % of the triathletes (N=20) developed an episode of URTI during the 3 months post-Ironman®. Dietary intake parameters measured three months pre-Ironman® that had a significant influence on URTI were: potassium (p=0.04) and thiamine (p=0.02) and dietary intake parameters measured 3 months post-Ironman® that had a significant influence on URTI were: total protein (p=0.04); isoleucine (p=0.03); leucine (p=0.03); phenylalanine (p=0.03); valine (p=0.02); thiamine (p=0.01); and Beta-tocopherol (p=0.03). Dietary intake parameters measured during the race that had a significant influence on URTI were: selenium (p=0.04); folate (p=0.04) and proline (p=0.02). Body composition did not have a significant influence on URTI. Conclusion: Habitual dietary intake three months pre- and post-Ironman® as well as pre- and post Ironman race strategies were low for carbohydrate. Body composition indicated that athletes were at the upper end associated with endurance sport. There was a relationship found between an episode of URTI and dietary intake.
AFRIKAANSE OPSOMMING: Agtergrond: Die Ironman® driekamp is 'n ultra-uithouvermoë kompetisie. Daar is voorheen bewys dat swaar oefening skedules en ultra-uithouvermoë kompetisies kan lei tot ‘n immuungebrek. Daar is tans ‘n tekort aan wetenskaplike bewyse wat die potensiële rol van dieetinname en liggaamsamestelling op immuungebrek of boonste lugweginfeksies ondersoek. Doel: Die doel van die studie was om ondersoek in te stel oor die verhouding tussen dieetinname, liggaamsamestelling en die insidensie van boonste lugweg infeksies in driekamp atlete woonagtig in Port Elizabeth (PE), tydens oefening en deelname aan die Ironman® 2011 driekamp. Metodes: 'n Waargenome, longitudinale beskrywende studie is gedoen met 'n analitiese komponent. Die studiepopulasie het bestaan uit driekampatlete woonagtig in PE, wat 'n Ironman® afstand kompetisie voltooi het een jaar voor en wat oefen vir die April 2011 Ironman® kompetisie. Gewoontelike dieetinname is bepaal met 'n kwantitatiewe voedselfrekwensie vraelys, en dieet strategieë rondom die byeenkoms met 'n drie dag voedselrekord. Liggaamsamestelling is bepaal met antropometrie en die insidensie van boonste lugweg infeksies is bepaal met die WURSS-44. 'n algemene gesondheid vraelys (SF- 36) is ook ingevul. Resultate: Die gewoontelike dieetinname gedurende die drie maande voor- en na-Ironman® 2011 was voldoende vir alle voedingstowwe, behalwe vir koolhidraat-inname in die vroulike en manlike deelnemers (voor Ironman® 4.0 (1.7) g / kg liggaamsmassa (LM) / dag en 5.4 (1.8) g / kg LM / dag, en na Ironman® 3.0 (1.0) g / kg LM / dag en 4.7 (1.5) g / kg LM / dag onderskeidelik). Koolhidraatlading strategieë was ontoereikend met innames van 6.0 (2.9) en 5.1 (2.5) g / kg BW / dag vir vroulike en manlike deelnemers onderskeidelik. Die inname op die dag van die byeenkoms was onvoldoende vir koolhidraat. Die dieetinname na die byeenkoms was onvoldoende vir koolhidraat inname in die vroulike deelnemers (0.9 (0.5) g / kg LM). Die liggaamsmassa-indeks was 26.6 (3.4) kg/m2 en 26.1 (1.4) kg/m2 vir vroulike en manlike deelnemers onderskeidelik. Persentasie liggaamsvet was aan die boonste grens geassosieer met uithouvermoë oefening atlete 29.3 (9.4) % en 13.7 (5.1) % vir vrouens en mans onderskeidelik. Die insidense van boonste lugweg infeksies was 25% (N=20) gedurende die drie maande na Ironman®. Dieetinname paramters wat gemeet was drie maande voor Ironman® wat beduidende beïnvloed met boonste lugweginfeksies getoon het, was, kalium (p=0.04) en tiamien (p=0.02) en die dieetinname parameters wat drie maande na Ironman® gemeet is en betekenisvolle beïnvloed getoon het met boonste lugweginfeksies was, totale proteïen (p=0.04); isoleusien (p=0.03), leusien (p=0.03), fenielalanien (p=0.03), valien (p=0.02), tiamien (p=0.01), en B-tocopherol (p=0.03). Die dieetinname parameters wat gemeet was tydens die wedloop wat beduidende beïnvloed met boonste lugweginfeksies getoon het na Ironman® 2011 was, selenium (p=0.04), folaat (p=0.04) en prolien (p=0.02). Die antropometriese parameters gemeet het nie beïnvloed op boonste lugweginfeksies gehad nie. Gevolgtrekking: Die gewoontelike dieetinname drie maande voor- en na Ironman® sowel as voor- en na Ironman® kompetisie strategieë was onvoldoende vir koolhidrate. Liggaamsamestelling het aangedui dat atlete aan die boonste grens geassosieer met uithouvermoë oefening geval het. Daar was beduidende beïnvloed gevind tussen dieetinname en boonste lugweginfeksies.

Introduction. Stone crushing in Dar-es-Salaam Tanzania is largely an informal occupational activity, with approximately 7000 workers exposed to varying level of respirable dust. A highly marginalized, self employed, informal stonecrusher is prone to multiple work related risks, particularly dust related respiratory diseases. Aim. This study, the first to be done among informal stone crushers in Southern Africa, aimed at determining the prevalence of dust related respiratory outcomes and relationships between these health endpoints and exposure to respirable dust in this sample of stonecrushers. Methods. This was primarly a cross-sectional descriptive study with analytic components. This study analysed a subset of data collected in a health survey of stone crushers in Kigamboni informal stone quarry in Dar-es-Salaam, Tanzania in 2007. All 200 workers working in the quarry were interviewed. A subset of 86 and 59 workers underwent exposure assessment and health assessments (spirometry and chest radiography) respectively. Associations were investigated between exposure measures and respiratory outcomes. Results. The average age of the workers was 36.3 years with 51.5% males participating in the study. Smoking was common with 30.1% male, 8.25% female smokers, with 2% ex-smokers. Personal dust sampling showed varying dust levels ranging from 0.5-2.8mg/m3 with geometric mean of 1.2gm/m3. The exposure duration of workers in the quarry ranged from 1-62 years with mean of 7.8 years. No single worker was found to use personal protective equipment at work. Reported prevalence of doctor diagnosed respiratory diseases was low: pulmonary tuberculosis (2%), chronic bronchitis (2%), asthma (3%), pneumonia (3%). In contrast, there was high prevalence of respiratory symptoms: chronic cough (13.5%), phlegm production (14.5%), productive cough (10%), wheezing (14%), mild breathlessness (9.5% ) and coughing blood (7.5%). Mean forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) adjusted for age, height and sex was 2.6L/min and 3.7 L respectively, among males and 2.1L/min and 3.0L respectively among females. Adjusted exposure odds ratios for symptoms were statistically significant for mild and moderate breathlessness with odds ratios of 3.4 and 3.1 respectively. Linear regression showed statistically significant decline of 2.3mls in FEV1 with years of exposure while controlling for sex, age, height , doctor diagnosed TB and smoking showing that with prolonged exposure in the quarry, workers are at a risk of developing obstructive lung disease. This trend was not evident for FVC. The majority of films were normal (60.9%), with 19.6% read as 1/0 and 19.9% as 0/1. Discussion. This study identified adverse respiratory outcomes among informal stonecrushers, particularly a high prevalence of respiratory symptoms and clinically important lung function deficits. These are in keeping with other environment studies where workers were exposed to respirable dust. Recommendations. Urgent policy initiatives for developing cost effective hazard control, engineering interventions to protect these marginalized self-employed informal sector stonecrushers are needed.
Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2010.

Inorganic arsenic exposure is a well-known toxicant of which we are still discovering harmful effects. People are exposed to inorganic arsenic in the environment through either drinking arsenic-contaminated groundwater or consuming arsenic-contaminated food. Regarding global public health, drinking water is still the most important source of inorganic arsenic exposure and is the main focus of this work. The overall goal of this dissertation is to answer some pointing epidemiological questions about exposure to inorganic arsenic: How much do we know about inorganic arsenic and non-malignant lung disease in the general population? To what extent are adolescents with lifetime arsenic exposure susceptible to the respiratory consequences seen in adults? And what actions can be taken to effectively reduce exposure from arsenic-contaminated drinking water? First, we conducted a systematic review of 29 peer-reviewed articles from various populations around the world. The review focused on the different ways in which arsenic is associated with respiratory health to help inform policy makers and public health researchers on the existing evidence. In short, associations between arsenic and respiratory health were noted throughout the lifespan: in infancy, there was growing evidence that in utero arsenic exposure was associated with increased frequency and severity of respiratory tract infections; in childhood, evidence of respiratory symptoms also began to appear; and in adulthood, there was consistent evidence that arsenic exposure was associated with deficits in lung function and increased reports of coughing and breathing problems. The review also uncovered some research gaps, including few studies with strong exposure history from early life and few studies examining respiratory effects during adolescence. Next, we used a life course epidemiological approach to create a more precise understanding of arsenic exposure and respiratory health during the teenage years. This study examined the relationship between lifetime arsenic exposure and lung function in 14-17 year olds, thus studying the period of maximal lung function before natural decline. Overall, higher arsenic exposure was associated with lower lung function levels; however, these associations were only observed in males. This study used a sensitive marker of lung function to investigate early signs of small airway disease. Incorporating this common marker of small airway disease and airflow limitation in future studies on arsenic and respiratory health may help clarify how inorganic arsenic contributes to the development of chronic respiratory disease. Lastly, we evaluated the effectiveness of arsenic removal filters at the household-level in rural Bangladesh. Identifying sustainable ways of reducing exposure to arsenic from naturally contaminated groundwater has been a major environmental health challenge. Although lab-approved arsenic removal water filters exist, there was limited evidence of their prolonged efficacy in the field. To our knowledge, this was the largest and longest deployment of filters accompanied by monitoring of urinary arsenic. Our results demonstrated that filters can temporarily reduce arsenic exposure for weeks to a few months, but should not be considered as a long-term arsenic mitigation option. This failed attempt to reduce exposure confirmed that alternative mitigation strategies need to be employed in Bangladesh, particularly among more vulnerable populations, including pregnant women and young children. This dissertation has important policy implications for future arsenic research and mitigation efforts and should be effectively communicated to policy makers, public health officials, and the general population. Given the pervasive nature of arsenic exposure and the growing evidence of health consequences at different stages throughout the life course, the continued integration of information on inorganic arsenic and research collaborations across disciplines is critical for the prevention and mitigation of arsenic-induced health consequences.

Introduction: Numerous studies have found associations between exposure to airborne particulate matter and respiratory morbidity and mortality. However, the varying composition, dependant on the different sources of particulate matter, and its effect on processes of inflammation and oxidative stress in the airways has not been completely elucidated. The use of airway biomarkers, fractional exhaled nitric oxide (FENO) and exhaled breath condensate (EBC), can provide valuable insight into processes of inflammation and oxidative stress in the airways. In these studies we sought to characterize the associations between airborne pollutant exposures and their sources and airway biomarkers. Methods:The study population of interest for Chapters III-V is a subset of children currently enrolled in a birth cohort under the Columbia Children's Center for Environmental Health. Chapter III refers to the validation in this population of a method for partitioning FENO contributions from the proximal and distal airways. Chapters IV and V refer to the implementation of this method in the study of ambient metals and residential proximity to relevant sources of particulate matter (PM) and black carbon (BC). Briefly, the children of African-American and Dominican mothers living in low-income NYC neighborhoods had FENO samples collected offline at constant flow rates of 50, 83 and 100 mL/sec at ages 9 and/or 11. Surrogate measures for bronchial flux NO (JNO) and alveolar (Calv) NO concentrations were estimated using a previously validated mathematical model. Wheeze in the last 12 months was assessed by the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Seroatopy was determined by specific IgE at age 9. For Chapter IV, in order to examine the associations between metal fractions of particulate matter and airway inflammation, ambient measures of Ni, V, Zn and Fe were obtained from a local central monitoring site and averaged over nine days based on three 24 hour measures every third day. Seroatopy was determined by specific IgE at age 7. For Chapter V, residential distance to a major road, truck route and bus stop density, area covered by major roads, stationary point sources (SPS), toxic release inventory sites (TRIS) and commercial buildings, and number of buildings burning residual oil within 250-meters of each child's home were determined. These variables were selected a priori as potential important sources or airborne PM and BC. For Chapter VI, the study population was comprised of seven- and eight-year-old children enrolled in an asthma case-control study in New York City. Seven day averages of domestic levels of particulate matter <2.5 microns (PM2.5), BC and environmental tobacco smoke (ETS) were measured. Urea and 8-isoprostane were measured by liquid chromatography tandem mass spectrometry (LC/MS/MS) in EBC collected during home visits. All data were analyzed with SPSS. Results: In our first study, children with seroatopy had significantly higher median JNO p<0.001) when compared to non-seroatopic children; however, median Calv was not significantly different between these two groups (p=0.644). Children with wheeze in the past year had significantly higher median Calv (p<0.001), but not JNO (295 vs. 165 pL/s, p=0.241) when compared with children without wheeze. In our second study, ambient V and Fe concentrations were associated positively with FENO50 (p=0.018, p=0.027). Ambient Fe was associated positively with JNO (p=0.017). Ambient Ni and V concentrations were associated positively with Calv (p=0.004, p=0.018 respectively). A stronger association of Ni concentrations with Calv was observed among the children with seroatopy. In our third study, there were no significant associations between any of the air pollution indicator variables and FENO parameters in adjusted models. In our final study, PM2.5and BC, but not ETS, were significantly associated with increases in 8-isoprostane (p<0.05 for both) after adjustment for covariates. In a co-pollutant model including PM2.5, BC and ETS, only BC remained a statistically significant predictor of 8-isoprostane. Discussion: Recent exposure to airborne pollutants was associated with increased levels of biomarkers of airway inflammation and oxidative stress measured in exhaled breath. The metal and BC fractions of PM might be more relevant to the understanding adverse respiratory outcomes related to air pollution exposure.

In order to evaluate the respiratory health status of spray painters exposed to paints containing hexamethylene diisocyanates (HDI) and to obtain more insight into the relationship between occupational exposures to isocyanates and chronic obstructive airway diseases, a follow up study on 33 of an original cohort of 40 randomly selected workers was undertaken. The original investigation was conducted by the author in 1989. The subjects were studied using a standardised American Thoracic Society (ATS) approved respiratory health questionnaire, baseline pre and post shift spirometry and ambulatory peak flow monitoring. Bronchial hyperresponsiveness tests using histamine (PC20) were performed. Immunological tests including IgE, RAST (HDI), and house dust mite evaluations were also made. The subjects were stratified into exposed (n=20), partially exposed (n=5) and no longer exposed (n=7) groups. One subject was excluded from the group analysis because of his indeterminate isocyanate exposure. Warehouse assistants (n=30) in a non-exposed occupation were used as controls. The worker's compliance with safety regulations and the employers provision of safety requirements was assessed by means of a questionnaire. The environmental conditions in the workplace were measured by the evaluation of the isocyanate concentrations at the worker's breathing zone. Spray booth efficiency was measured using measurements of airflow velocities and airflow patterns within the booth. Longitudinal changes in respiratory health status was assessed by comparison with baseline data studied in 1989. The exposed group showed the largest mean cross-shift declines of 297 ml (± 83.8) in forced expiratory volume in one second (FEV1). The decline in the partially exposed group was 282 ml (± 102.7) and 54 ml (± 140) in the no longer exposed group. The results of the first study, when compared with the second study, showed a mean cross-shift decline in FEV1 of 130.5 ml. (± 203) (p=0.0002) and 297ml. (± 323) (p=0.0001) respectively. Furthermore, of the spray painters examined, 10 (25%) showed clinically significant cross-shift declines in FEV1 viz. decreases >250 ml in the first study (n=40) compared with 9 (45%) in the second study (n=33). In contrast to the HDI exposed spray painters, a closely matched control group (n=30) showed a mean cross-shift increase in FEV1 of 17.4 ml ( ± 63.04). Only 2 subjects had a diagnosis of asthma which was made in childhood and not related to occupation. The mean annual baseline decline in FEV1 was greatest in the exposed group 41.25 ml (25% showed a decline greater than >90 ml per annum). These values exceeded the predicted annual declines for both smokers and non smokers due to age. The decline in the no longer exposed group was 7.85 ml per annum. Immunological tests showed no correlation with declines in FEV1 . This study demonstrates the difficulties in correlating immunological status with clinical and lung function findings in workers exposed to HDI, as a means of predicting occupational asthma. Although measurements in cross-shift declines in FEV1 appear to be a suitable predictor of occupational asthma, in some cases it was found that the forced expiratory flow rate (FEF 25-75 %) was a more sensitive predictor of early changes in the small airways. The mean isocyanate concentration in the spray painter's breathing zone was 14.65 mg/m3 (±12.219), exceeding the current South African Occupational Exposure Limit - Control Limit (OEL-CL) of 0.07 mg/m3 for isocyanates. Fifty per cent of the subjects suffered from eye irritation and 40% had dermatitis of the hand. This was expected since none of the spray painters wore goggles or gloves. Whilst no subject had evidence of clinical asthma related to spray painting, a large proportion demonstrated significant cross- shift changes in lung function implying short- term adverse effects of exposure. In addition longitudinal declines in lung function which was worse in those who continued spray painting in the follow-up study, is of major concern. The lack of cases of clinical or occupational asthma may be due to the healthy worker effect. Recommendations include, routine spirometric lung function testing of all spray painters, the use of high volume-low pressure spray guns and the wearing of positive pressure airline masks complying with the South African Bureau of Standards (SABS) safety standard. In terms of current legislation it was further recommended that spray booths be regularly monitored, including the measurement of HDI concentrations, airflow velocities and airflow patterns within the booth and the implementation and enforcement of stricter control measures. Workers demonstrating excessive declines in both cross-shift and longitudinal spirometry, require special attention.
Thesis (M.Med.Sc.)-University of Natal, 1997.

Dampness can cause the development of moulds in buildings and pose a threat to the quality of the building structure, indoor air quality and health of the occupants. An emerging source of housing related problems are the building materials commonly used in housing construction, which can influence respiratory health. There is concern regarding the quality of the housing stock in the Durban Metropolitan area with regard to dampness and its the potential impact on the health of occupants. To elucidate this issue, a study was conducted to assess natural ventilation, dampness and mouldiness in dwellings of the Waterloo Housing development (Durban Metropolitan Area), between February 2001 and December 2003. A total of 491 randomly selected homes were visually inspected and residents were surveyed by means of a structured questionnaire. Three hundred and eighteen (318) air and surface mould samples were collected in duplicate, totalling 636 samples and analysed in the laboratory. Building characteristics and physical conditions were recorded and noted. Temperature and relative humidity readings were also taken during the survey. After the analysis of the 491 questionnaires, physical conditions of the dwellings were found to be poor and of concern. With the number (1178) and size of habitable rooms in the dwellings; the occupancy of 2414 people with an average of 2.05 persons per room, indicated overcrowding and congestion. About 51% (n=249) of the dwellings surveyed were found to be experiencing dampness (>3m2) and 47% (n=230) had visible surface moulds, primarily on the walls (at least an average of 1m2) . Predominant airborne fungal organism identified included; Aspergillus (23%-indoors, 26outdoors), Cladosporium (47%- indoors, 51%-outdoors), Penicillum (27%-indoors, 26%-outdoors) spp. Natural ventilation was also inadequate in 261 (53%) dwellings, which did not have airbricks. This inadequacy significantly promotes the occurrence of dampness and surface moulds (p < 0.05). With poor ventilation, dampness and mould growth in the dwellings, there was a high number of cases with upper respiratory tract health complaints; like Cough - 25% (n=122), Sinuses - 25% (n=121), flu symptoms 23% (n=llO) lower respiratory infections such as asthma - 27% (n=130), and chest infections - 23% (n=113). Asthma, wheeze, runny nose and allergy to dust were statistically associated with dampness (p < 0.05), mouldiness (p < 0.03) and lack of ventilation (p < 0.01). Buildings separate their occupants from hostile external environments and create a better internal environment for them, therefore dwellings must be constructed in a manner that promotes the health and well being of the occupants. In terms of guiding regulations, there were several omissions and non-compliance with existing local building bye-laws in the construction of houses, leading to adverse implications. Improved workmanship, appropriate material selection and compliance with the relevant guidelines during planning and construction inter alia, are recommended when addressing housing issues, thereby promoting the interest, health and well-being of the users.
Thesis-(M.Med)- University of KwaZulu-Natal, Durban, 2004.

Indiana University-Purdue University Indianapolis (IUPUI)
IL-17-producing T cells are critical to the development of pathogen and tumor immunity, but also contribute to the pathology of autoimmune diseases and allergic inflammation. CD8+ (Tc17) and CD4+ (Th17) IL-17-secreting T cells develop in response to a cytokine environment that activates Signal Transducer and Activator of Transcription (STAT) proteins, though the mechanisms underlying Tc17/Th17 development and stability are still unclear. In vivo, Tc17 cells clear vaccinia virus infection and acquire cytotoxic potential, that is independent of IL-17 production and the acquisition of IFN-γ-secreting potential, but partially dependent on Fas ligand, suggesting that Tc17-mediated vaccinia virus clearance is through cell killing independent of an acquired Tc1 phenotype. In contrast, memory Th cells and NKT cells display STAT4-dependent IL-23-induced IL-17 production that correlates with Il23r expression. IL-23 does not activate STAT4 nor do other STAT4-activating cytokines induce Il23r expression in these populations, suggesting a T cell-extrinsic role for STAT4 in mediating IL-23 responsiveness. Although IL-23 is important for the maintenance of IL-17-secreting T cells, it also promotes their instability, often resulting in a pathogenic Th1-like phenotype in vitro and in vivo. In vitro-derived Th17 cells are also flexible when cultured under polarizing conditions that promote Th2 or Th9 differentiation, adopting the respective effector programs, and decreasing IL-17 production. However, in models of allergic airway disease, Th17 cells do not secrete alternative cytokines nor adopt other effector programs, and remain stable IL-17-secretors. In contrast to Th1-biased pro-inflammatory environments that induce Th17 instability in vivo, during allergic inflammatory disease, Th17 cells are comparatively stable, and retain the potential to produce IL-17. Together these data document that the inflammatory environment has distinct effects on the stability of IL-17-secreting T cells in vivo.