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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.
1

The Characterization and Diagnosis of Late-Onset Psychotic Disorder: A prospective longitudinal case series

MacDougall, Arlene G. 10 1900 (has links)
<p>There is considerable confusion regarding the diagnosis of patients presenting with non-affective psychosis in the absence of a dementia or secondary to a general medical condition in the fifth decade and beyond. A number of different terms, diagnostic criteria and age-cut-offs have been applied to this presentation posing a challenge to clinicians and researchers alike. Despite diagnostic inconsistencies and conceptual uncertainty, a remarkably consistent clinical picture has emerged. However, many questions still remain with regards to its underlying etiopathophysiological mechanisms, treatment and prognosis, including whether it is distinct from schizophrenia and whether it might be a prelude to cognitive deterioration. Currently there is no official diagnostic designation for patients who develop a primary psychosis in late life, with patients being typically diagnosed as either schizophrenia or delusional disorder, although the validity of such a distinction has been questioned.</p> <p>The following prospective longitudinal study sets out to characterize the largest known group of patients (n=102) with first-episode, late-onset (>age 40) psychotic disorder on demographic, clinical, treatment and prognostic variables. Given that one of the most contentious issues in the characterization of these patients has been that of diagnostic classification, we examined whether the currently nosological distinction of schizophrenia (SCZ) from delusional disorder (DD) has validity and/or utility. Patients were classified as either SCZ (n=47) or DD (n=55) according to DSM-IV criteria, and were then compared on a number of validators proposed as part of the DSM-V development process. As predicted, there were no significant differences between the two groups. In conclusion, our analysis did not find the current diagnostic distinction of SCZ from DD in the late-onset population to be valid and/or useful. We recommend the use of the more general diagnostic term, “Late-Onset Psychotic Disorder”, to refer to all patients who develop a primary psychosis in their forties or beyond.</p> / Master of Science (MSc)
2

Zur lokalen Epidemiologie multiresistenter biofilmbildender Staphylococcus epidermidis Stämme bei sehr kleinen Frühgeborenen und ihren Müttern / Local epidemiology of multi-resistant biofilm forming Staphylococcus epidermidis strains in very low birth weight infants and their mothers

Gellichsheimer, Eva January 2012 (has links) (PDF)
Das grampositive Bakterium Staphylococcus epidermidis ist ein wesentlicher Bestandteil der kommensalen Flora der Haut und der Schleimhäute des Menschen. Jedoch stellen diese Bakterien eine häufige Ursache nosokomialer Katheter-assozierter Infektionen bei immunsupprimierten Patienten dar. Dies liegt zum einen an der Fähigkeit von S. epidermidis, Biofilm zu bilden. Diese physikalische Barriere schützt die Bakterien vor dem Immunsystem sowie vor Antibiotika. Dabei zählen sie zu den häufigsten Erregern von Infektionen an implantierten Fremdkörpern mit Plastikoberflächen, wie z. B. Venenkathetern, künstlichen Herzklappen oder Gefäßprothesen. Zum anderen stellt die Antibiotikaresistenzentwicklung unter S. epidermidis ein zunehmendes Problem dar. Vor allem die late-onset Sepsis, die durch S. epidermidis als Erreger verursacht werden kann, stellt für Frühgeborene eine Gefahr dar. Ziel der vorliegenden Arbeit war, für S. epidermidis als häufigsten und klinisch bedeutsamen KoNS zu eruieren, ob die zunehmende Dauer des stationären Krankenhausaufenthaltes von sehr kleinen Frühgeborenen mit einer höheren Rate an ica-Präsenz, Biofilmbildung und Antibiotikaresistenz assoziiert ist, sowie die Verbreitungswege und das Reservoir für diese S. epidermidis-Stämme zu identifizieren. Hierzu wurden sequenzielle Isolate von S. epidermidis bei Müttern, Kindern und vom Krankenhauspersonal gewonnen und mittels MLST (Multilocus-Sequence-Typing) klonal typisiert. Sie wurden auf Antibiotikaresistenzen, Biofilmbildung und Präsenz des icaA-Gens, das eine Rolle bei der Biofilmbildung spielt, sowie des mecA-Gens untersucht und mit Isolaten, die aus Blutkulturen oder Venenkatheter des Kindes isoliert wurden, verglichen. Es fiel auf, dass die Isolate der sehr kleinen Frühgeborenen deutlich mehr Virulenzfaktoren, wie z.B. Biofilmbildung, hohe Antibiotikaresistenzraten sowie die Präsenz des mecA- und des icaA- Gens, als die maternalen Stämme besaßen. Im Vergleich mit den Ergebnissen der untersuchten Personalstämme liegt der Verdacht nahe, dass oftmals auch das Personal als Transmitter, vor allem von Klonen mit mehreren Virulenzfaktoren, dient. Das Krankenhaus-Milieu scheint dabei ein ideales Reservoir für die Ausbreitung solcher gefährlichen S. epidermidis-Stämme zu sein. / Staphylococcus epidermidis is usually a commensal inhabitant of the human skin and mucosa. However, they are a common cause of nosocomial infections, especially in context with medical devices and catheters in immunocompromised patients. This is due to the ability of Staphylococcus epidermidis to form biofilms on inert surfaces of medical devices, like intravenous catheters or artificial arthroplastics. Furthermore the development of antibiotic resistances among Staphylococcus epidermidis is another problem. Especially the late-onset-sepsis is a danger for very low birth weight premature infants. The aim of the study was to identify for S. epidermidis isolates in very preterm infants, if a longer stay in the hospital is associated with a higher carriage of the ica-operon, a higher antibiotic resistance and the ability to form biofilms. The reservoir and the means of distribution of these nosocomial isolates should be idendified. Therefore sequential isolates were taken from mothers, their children and from the hospital staff. They were clonally typified by MLST (Multilocus-Sequence-Typing) and tested for antibiotic resistances, biofilm formation and the presence of the icaA- and mecA gene. Then they were compared with isolates from blood cultures or venous catheters from the preterm infants. Herby it was remarkable that the isolates of the very premature infants had more virulence factors, e.g. formation of biofilm, antibiotic resistances and the presence of the icaA- and mecA gene, as the maternal isolates. Compared to the results of the isolates from the medical staff it could be suggested that the staff transmits these opportunistic pathogens. The hospital environment seems to be an ideal reservoir for these dangerous S. epidermidis isolates.
3

Determinação dos níveis séricos e urinários da Interleucina 8 em recém-nascidos prematuros com sepse tardia /

Bentlin, Maria Regina. January 2003 (has links)
Orientador: Lígia Maria Suppo Souza Rugolo / Resumo: A sepse neonatal tardia é importante causa de morbidade e mortalidade em recém-nascidos prematuros. Os sinais e sintomas são inespecíficos, o que dificulta o diagnóstico. As citocinas são potentes mediadores inflamatórios que desempenham importante papel na patogênese da infecção. Níveis séricos aumentados de citocinas são observados durante infecções. A Interleucina 8 (IL-8) tem função de atrair e ativar neutrófilos, mantendo o processo inflamatório. O objetivo deste estudo foi determinar os níveis séricos e urinários da IL-8 em recém-nascidos prematuros com sepse tardia confirmada por culturas (sangue, urina ou líquor) ou associada com meningite, e avaliar se os níveis urinários de IL-8 podem ser utilizados como teste diagnóstico da sepse neonatal tardia. Amostras de sangue e urina foram coletadas de 36 RN prematuros com suspeita clínica de sepse tardia e os exames foram repetidos após 48 horas do início do estudo. Os valores séricos e urinários da IL-8 foram determinados pelo método de ELISA e a IL-8 urinária foi ajustada pelo valor da creatinina urinária. Dois grupos foram constituídos: Grupo séptico: 19 RN com sepse confirmada por culturas ou associada a meningite, idade gestacional (IG) de 31 ± 2,5 semanas, peso de nascimento (PN) de 1350 ± 420g, idade pós-natal (IPN) de 9,7 ± 5,3 dias e Grupo não infectado: 17 RN nos quais o diagnóstico de sepse foi excluído, IG 31 ± 2,1 sem, PN 1510 ± 380g, IPN 6,9 ± 4,1 dias. A mediana dos níveis séricos da IL-8 não diferiu estatisticamente entre os grupos séptico e não infectado (929 x 624 pg/ml; p=0,079) mas os níveis urinários (IL-8 ur/cr) foram significativamente maiores no grupo séptico (249 x 41,7; p<0,001). O ponto de corte ótimo da IL-8 sérica foi de 304 pg/ml com sensibilidade de 84% (IC 95%: 60 a 95%) e especificidade de 47% (IC 95%: 23 a 72%)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Late onset sepsis (LOS) is an important cause of morbidity and mortality in preterm infants. However, the diagnosis of LOS is difficult. Elevated serum levels of cytokines have been found during infections and this plays a critical role in the pathogenesis of infections. Interleukin 8 (IL-8) attracts and activates neutrophils which is crucial for the maintenance of the inflamatory process. The aim of this study was to determine serum and urine IL-8 levels in preterm infants with clinical LOS and positive culture (blood, urine ou cerebrospinal fluid) or meningitis and to evaluate if IL-8 levels can be a useful test for the diagnosis of LOS. Blood and urine were obtained from 36 premature babies with clinical signs of LOS and the collection of the samples were repeated after two days. Serum and urine IL-8 levels were determined by ELISA and the urine IL-8 concentration was corrected with the urine creatinine level. Nineteen preterm infants with sepsis (positive cultures or meningitis) - LOS Group: gestational age (GA) 31 ± 2.5wk, Birth Weight (BW) 1.35 ± 0.42 Kg, postnatal age(PNA) 9.7 ± 5.3 days and 17 noninfected - Control Group: GA 31 ± 2.1wk, BW 1.51 ± 0.38, PNA 6.9 ± 4.1 days, were studied. The medium serum IL-8 levels were not statistically different between groups (LOS vs Control, 929 x 624 pg/ml; p=0,079) but urine IL-8 levels were significantly higher in the LOS group when compared with the noninfected (249 x 41,7 p<0,001). The optimal cut-off point was 304pg/ml for serum IL8 with 84% sensitivity (95% CI: 60-95%) and 47% specificity (95% CI: 23-72%). The cut-off point for urine IL-8 was 89 with 100% sensitivity (95% CI: 82-100%) and 100% specificity (95%CI:81-100%). Two days after of clinical signs of LOS, urine IL-8 levels decreased in LOS group (p<0,001). The decrease in serum IL-8 levels in the LOS group was not statistically different (p=0,123)... (Complete abstract, click electronic address below) / Doutor
4

Mental health services and late-onset depression

McGill Fox, Eileen January 1900 (has links)
Master of Science / Department of Family Studies and Human Services / Candyce S. Russell / As the number of Americans aged 60 and over increases substantially in the coming years, so is the incidence of depression among this age group. The purpose of this report is to explore the mental health needs of older Americans, the ways in which they are undiagnosed or under-diagnosed for depression, the clinical challenges associated with treating depression in the elderly, and the barriers that are in place due to social, psychological, financial and governmental factors. With the “Baby Boom” generation (those born between 1946-1964) entering their senior years, there will be an increased need for Marriage and Family Therapists to be cognizant of the rise in depression and familiar with the treatment options and limitations. Marriage and Family Therapists adhere to the Systems Theory and thus are uniquely qualified to act as a bridge between the medical and mental health communities. This report will promote the collaborative approach to healthcare and the way in which Marriage and Family Therapists can contribute to the treatment of depression in the aged.
5

Determinação dos níveis séricos e urinários da Interleucina 8 em recém-nascidos prematuros com sepse tardia

Bentlin, Maria Regina [UNESP] January 2003 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T19:04:16Z : No. of bitstreams: 1 bentlin_mr_dr_botfm.pdf: 810873 bytes, checksum: 830e8baa1a9b44778883a83210feaf9d (MD5) / A sepse neonatal tardia é importante causa de morbidade e mortalidade em recém-nascidos prematuros. Os sinais e sintomas são inespecíficos, o que dificulta o diagnóstico. As citocinas são potentes mediadores inflamatórios que desempenham importante papel na patogênese da infecção. Níveis séricos aumentados de citocinas são observados durante infecções. A Interleucina 8 (IL-8) tem função de atrair e ativar neutrófilos, mantendo o processo inflamatório. O objetivo deste estudo foi determinar os níveis séricos e urinários da IL-8 em recém-nascidos prematuros com sepse tardia confirmada por culturas (sangue, urina ou líquor) ou associada com meningite, e avaliar se os níveis urinários de IL-8 podem ser utilizados como teste diagnóstico da sepse neonatal tardia. Amostras de sangue e urina foram coletadas de 36 RN prematuros com suspeita clínica de sepse tardia e os exames foram repetidos após 48 horas do início do estudo. Os valores séricos e urinários da IL-8 foram determinados pelo método de ELISA e a IL-8 urinária foi ajustada pelo valor da creatinina urinária. Dois grupos foram constituídos: Grupo séptico: 19 RN com sepse confirmada por culturas ou associada a meningite, idade gestacional (IG) de 31 ± 2,5 semanas, peso de nascimento (PN) de 1350 ± 420g, idade pós-natal (IPN) de 9,7 ± 5,3 dias e Grupo não infectado: 17 RN nos quais o diagnóstico de sepse foi excluído, IG 31 ± 2,1 sem, PN 1510 ± 380g, IPN 6,9 ± 4,1 dias. A mediana dos níveis séricos da IL-8 não diferiu estatisticamente entre os grupos séptico e não infectado (929 x 624 pg/ml; p=0,079) mas os níveis urinários (IL-8 ur/cr) foram significativamente maiores no grupo séptico (249 x 41,7; p<0,001). O ponto de corte ótimo da IL-8 sérica foi de 304 pg/ml com sensibilidade de 84% (IC 95%: 60 a 95%) e especificidade de 47% (IC 95%: 23 a 72%)... / Late onset sepsis (LOS) is an important cause of morbidity and mortality in preterm infants. However, the diagnosis of LOS is difficult. Elevated serum levels of cytokines have been found during infections and this plays a critical role in the pathogenesis of infections. Interleukin 8 (IL-8) attracts and activates neutrophils which is crucial for the maintenance of the inflamatory process. The aim of this study was to determine serum and urine IL-8 levels in preterm infants with clinical LOS and positive culture (blood, urine ou cerebrospinal fluid) or meningitis and to evaluate if IL-8 levels can be a useful test for the diagnosis of LOS. Blood and urine were obtained from 36 premature babies with clinical signs of LOS and the collection of the samples were repeated after two days. Serum and urine IL-8 levels were determined by ELISA and the urine IL-8 concentration was corrected with the urine creatinine level. Nineteen preterm infants with sepsis (positive cultures or meningitis) - LOS Group: gestational age (GA) 31 ± 2.5wk, Birth Weight (BW) 1.35 ± 0.42 Kg, postnatal age(PNA) 9.7 ± 5.3 days and 17 noninfected - Control Group: GA 31 ± 2.1wk, BW 1.51 ± 0.38, PNA 6.9 ± 4.1 days, were studied. The medium serum IL-8 levels were not statistically different between groups (LOS vs Control, 929 x 624 pg/ml; p=0,079) but urine IL-8 levels were significantly higher in the LOS group when compared with the noninfected (249 x 41,7 p<0,001). The optimal cut-off point was 304pg/ml for serum IL8 with 84% sensitivity (95% CI: 60-95%) and 47% specificity (95% CI: 23-72%). The cut-off point for urine IL-8 was 89 with 100% sensitivity (95% CI: 82-100%) and 100% specificity (95%CI:81-100%). Two days after of clinical signs of LOS, urine IL-8 levels decreased in LOS group (p<0,001). The decrease in serum IL-8 levels in the LOS group was not statistically different (p=0,123)... (Complete abstract, click electronic address below)
6

An investigation into the genetic basis of late-onset psoriasis

Hebert, Harry January 2015 (has links)
Background: Psoriasis is a complex disease with a genetic component contributing to disease pathogenesis. Chronic plaque psoriasis can be dichotomised into two subtypes according to age of onset; type 1 (early-onset; <40 years) and type 2 (late-onset; ≥40 years). Despite clinical and biological differences between the two subtypes, the genetics underpinning late-onset psoriasis remains poorly characterised compared to early-onset psoriasis. Aims: The aim of this project was to identify genetic loci associated with late-onset psoriasis, to assess the overlap of loci with early-onset psoriasis and to elucidate the functional role of the identified variants. Methods: The study had three parts; the first was a candidate-gene association study of the IL1B gene. A total of 16 SNPs from the region were genotyped in 595 late-onset and 1,137 early-onset psoriasis samples and compared to 4,770 controls from the European population. The second was a large-scale study conducted in 543 late-onset psoriasis and 4,373 controls using the Immunochip array. The third was a functional study using bioinformatics data mining, chromatin immunoprecipitation and electrophoretic mobility shift assay techniques to analyse the role of a disease-associated variant at the biological level. Results: The candidate-gene study replicated a previously reported association at a promoter polymorphism, rs16944 (P<0.05), within the IL1B gene and discovered a novel association at a second variant, rs11687624 (P<3.12x10-3), in late-onset psoriasis. None of the variants analysed were significantly associated with early-onset psoriasis. Bioinformatic eQTL data suggests the two variants and their proxies are associated with the expression of IL1A, IL1B, IL38 and PAX8. The Immunochip study identified 6 non-HLA loci (P<2.3x10-5) previously associated with early-onset psoriasis to also be associated with late-onset psoriasis (IFIH1, IL12B, IL23A, IL23R, TRAF3IP2 and ZNF313). Conditional analysis of the MHC region also identified two loci (HLA-C and HLA-A). A novel locus, IL1R1, was associated with late-onset psoriasis, but not early-onset psoriasis. Bioinformatic data mining found no role for the IL1R1 variants as eQTLs and prioritised the IL1B variant rs2708914 for functional analysis. The transcription factor STAT3 was found to be enriched at rs2708914 in keratinocyte and CD8+ T-lymphocyte cell lines. Allele-specific binding could not be established. Conclusions: This project is the largest genetic study of late-onset psoriasis to date and provides evidence that it shares susceptibility loci with early-onset psoriasis as well as having specific susceptibility loci. These findings provide further evidence for the dichotomisation of chronic plaque psoriasis, firstly to facilitate better understanding of the pathogenesis of the two subtypes and secondly to enable tailored therapy to be developed. Both have potential benefits for patients in the future. The genetic and functional studies conducted have provided a platform from which further studies can be carried out.
7

Bayesian Adaptive Dose-Finding Clinical Trial Designs with Late-Onset Outcomes

Zhang, Yifei 07 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The late-onset outcome issue is common in early phase dose- nding clinical trials. This problem becomes more intractable in phase I/II clinical trials because both toxicity and e cacy responses are subject to the late-onset outcome issue. The existing methods applying for the phase I trials cannot be used directly for the phase I/II trial due to a lack of capability to model the joint toxicity{e cacy distribution. We propose a conditional weighted likelihood (CWL) method to circumvent this issue. The key idea of the CWL method is to decompose the joint probability into the product of marginal and conditional probabilities and then weight each probability based on each patient's actual follow-up time. We further extend the proposed method to handle more complex situations where the late-onset outcomes are competing risks or semicompeting risks outcomes. We treat the late-onset competing risks/semi-competing risks outcomes as missing data and develop a series of Bayesian data-augmentation methods to e ciently impute the missing data and draw the posterior samples of the parameters of interest. We also propose adaptive dose- nding algorithms to allocate patients and identify the optimal biological dose during the trial. Simulation studies show that the proposed methods yield desirable operating characteristics and outperform the existing methods.
8

Sympathetic innervation of ciliary muscle and oculomotor function in emmetropic and myopic young adults.

Mallen, Edward A.H., Gilmartin, B., Wolffsohn, J.S. January 2005 (has links)
No / Purpose: Evidence exists for an additional inhibitory accommodative control system mediated by the sympathetic branch of the autonomic nervous system (ANS). This work aims to show the relative prevalence of sympathetic inhibition in young emmetropic and myopic adults, and to evaluate the effect of sympathetic facility on accommodative and oculomotor function. Methods: Profiling of ciliary muscle innervation was carried out in 58 young adult subjects (30 emmetropes, 14 early onset myopes, 14 late onset myopes) by examining post-task open-loop accommodation responses, recorded continuously by a modified open-view infrared optometer. Measurements of amplitude of accommodation, tonic accommodation, accommodative lag at near, AC/A ratio, and heterophoria at distance and near were made to establish a profile of oculomotor function. Results: Evidence of sympathetic inhibitory facility in ciliary smooth muscle was observed in 27% of emmetropes, 21% of early-onset myopes and 29% of late-onset myopes. Twenty-six percent of all subjects demonstrated access to sympathetic facility. Closed-loop oculomotor function did not differ significantly between subjects with sympathetic facility, and those with sympathetic deficit. Conclusions: Emmetropic and myopic groups cannot be distinguished in terms of the relative proportions having access to sympathetic inhibition. Presence of sympathetic innervation does not have a significant effect on accommodative function under closed-loop viewing conditions.
9

Investigating a C1QTNF5 mutation associated with macular degeneration

Slingsby, Fern January 2009 (has links)
C1QTNF5 is a 25kDa short chain collagen of unknown function which is mutated in late-onset retinal macular degeneration (L-ORMD). L-ORMD is an autosomal dominant disease characterised by sub-retinal pigment epithelial deposits leading to photoreceptor death and visual loss and shows several similarities to age-related macular degeneration (AMD). A Tyr402His polymorphism in complement factor H (CFH), a regulatory protein in the innate immune system, has been associated with increased risk of AMD. C1QTNF5 and CFH are both expressed and secreted by the retinal pigment epithelium (RPE) which supports photoreceptors and is responsible for phagocytosis of shed rod photoreceptor outer segments (ROS). The properties of the normal C1QTNF5 and disease-associated Ser163Arg mutation were examined in detail, including protein characterisation, cellular processing and function. Recombinant wild type and mutant C1QTNF5 were produced and their multimerisation and solubility functions compared. Both proteins were found to be soluble and to form similar multimeric species which were resistant to reducing conditions, as seen in other short chain collagens. Due to the similarities between LORMD and AMD, a proposed interaction between C1QTNF5 and CFH was investigated. CFH is composed of 20 short consensus repeats (SCR) and interactions were confirmed between C1QTNF5 and both CFH and SCR modules 7-8 and 19-20. CFH showed a greater affinity for mutant C1QTNF5 compared with wild type on the basis of surface plasmon resonance assays. Stably transfected RPE-derived cell lines were created which expressed either wild type or mutant C1QTNF5. Both proteins were found to be secreted and showed similar cellular processing with no evidence of aggregation or retention of the mutant protein within the endoplasmic reticulum. In order to investigate C1QTNF5 function, phagocytosis of ROS by the stably transfected cell lines was carried out. Cells expressing wild type C1QTNF5 showed greater ROS phagocytosis compared with mutant C1QTNF5-expressing or untransfected cells. Addition of anti-C1QTNF5 antibody increased ROS phagocytosis further. In summary, it is proposed that wild type and mutant C1QTNF5 are secreted by the RPE where they interact with CFH. C1QTNF5 is also shown to have a role in ROS phagocytosis, with mutation in C1QTNF5 affecting phagocytosis efficiency, which may contribute to sub-RPE deposit formation. The results suggest that CFH may also be involved in this process, suggesting a common pathogenic pathway between L-ORMD and AMD.
10

Development of allergy, salivary IgA antibodies and gut microbiota in a Swedish birth cohort

Sandin, Anna January 2008 (has links)
The increasing prevalence of allergic diseases in affluent societies has been associated with changes in microbial exposure early in life and a less diverse gut flora. The objective of this thesis was to assess the development of allergic sensitisation and symptoms during the first four years of life in a non-selected birth cohort in relation to environmental factors, family history, gut microbiota and salivary IgA antibodies. The cohort comprised all 1,228 infants living in a Swedish county who were born over a one-year period. The parents replied to questionnaires, and 817 children (67 %) were skin prick tested both at 1 and 4 years of age. Saliva (n=279), faecal (n=139) and blood (n=253) samples were collected at 1 year of age from children with a positive skin prick test at 1 year and from a sample of children with a negative skin prick test. Faecal samples were also obtained from 53 children at 4 years of age. Dog keeping during infancy was associated with a decreased risk of sensitisation to pollen and late-onset wheezing at age 4, and the reduced odds ratios persisted after adjustment for heredity and avoidance measures, OR 0.3, 95% CI 0.1-0.9 and OR 0.5, 95% CI 0.2-1.0, respectively. In contrast, early dog keeping was associated with an increased risk of earlyonset transient wheezing but only in children with parental asthma (OR 2,8, 95% CI 1.3-6.4). Levels of short chain fatty acids (SCFAs) in faeces were assessed both at 1 and 4 years of age and related to the development of sensitisation and symptoms. The levels of acetic (p&lt;.01) and propionic (p&lt;.01) acids decreased from one to four years of age, whereas valeric acid (p&lt;.001) increased which is in line with a more complex gut microbiota with age. Allergic children, compared with non-allergic children, had lower levels of i-butyric, i-valeric and valeric acid in faeces both at 1 and 4 years of age. Low levels of secretory IgA (SIgA) in saliva were associated with wheezing but only in sensitised children. In children with positive SPT to at least one allergen both at 1 and 4 years of age and in children with circulating IgE antibodies to egg or cat at one year of age, those who developed late-onset wheezing had lower levels of SIgA than those who did not, p=.04 and p=.02 respectively. Of 9 children with levels of SIgA in the upper quartile and persistent sensitisation, none developed wheezing, compared with 10/20 children with lower levels, (p=. 01). Having older siblings, more than three infections during infancy, at least one smoking parent and male gender were all associated with high levels (in the upper quartile) of total IgA and SIgA. The findings in this thesis indicate that the microbial load early in life could affect the development of allergy. A functional assessment of the gut flora demonstrated differences between allergic and non-allergic children both at 1 and 4 years of age. Salivary IgA was associated with infections during infancy, and high levels of secretory IgA protected from symptoms in sensitised children. Finally, dog keeping in infancy may offer protection from allergy, but the mechanism is uncertain.

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