HIV-1 is the causative agent for AIDS and has been a major focus of research for the past two decades. Though there is a combination therapy in place known as the “Highly Active Anti-Retroviral Therapy” (HAART), its usefulness is confounded by the generation of escape mutants, a host of side effects, and its prohibitive cost. The most useful alternative would be the prevention of infection by vaccination. Vaccine research has been focused on the use of recombinant protein sub-units of the virus or combinations thereof to elicit a neutralizing response against the virus. These approaches have mostly resulted in a failure to generate broadly cross reactive neutralizing response against primary strains of the virus. The work reported herein is aimed at designing a rigidified version of gp120/gp120 derivatives and understanding the scope of the various antigenic regions in gp120 in generating a neutralization response. Chapter one discusses some general features of the virus and the immune system. The general nature of AIDS, its spread and its immunological characteristics are also described in this chapter. Chapter two discusses the design and NMR structural analysis of gp120 bridging sheet peptide mimics in methanol and water. The structure of gp120 can be loosely divided into two domains (the outer domain and the inner domain) that are linked together by a discontinuous four stranded antiparallel beta sheet known as the bridging sheet. The bridging sheet is known to overlap with the coreceptor binding site of gp120 and hence is a suitable target for designing virus-entry inhibitors. 17b, a neutralizing antibody isolated from an infected individual, is known to bind to this region of gp120. Our aim in this part of the work was to design a four stranded antiparallel beta sheet, based on the sequence of the bridging sheet, that would contain most of the residues involved in 17b binding. NMR and CD studies confirmed that the peptide was well structured in methanol but the structure was largely lost on addition of aqueous solvent. A small population of the peptide was found to be well-folded in aqueous solution. Chapter three discusses the design and characterization of a gp120-CD4D12 single chain. It is well known that the conformation of gp120 changes upon binding CD4 to expose cryptic epitopes, known as CD4i epitopes. In this work we report the generation of a single chain gp120-CD4 construct that has the cryptic epitopes exposed. The construct bound to 17b, a conformation specific antibody against the bridging sheet of gp120, a cryptic epitope, as well as a non-covalent complex of gp120:CD4D12. There was also very insignificant secondary structural change in gp120 upon complex formation with CD4D12 as observed by CD spectroscopy. Immunological studies with DNA and protein vaccination in guinea-pigs indicated that though 17b like antibodies are generated after immunization, they did not contribute towards the neutralization of primary isolates of the virus. It was also observed that it was the anti-CD4D12 antibodies that were responsible for the neutralization by the sera. These studies indicated towards the inability of the bridging sheet to generate effective neutralization response in case of vaccination with gp120/CD4 complexes. Chapter four discusses the design of a mimic of the gp120/CD4 complex. Since it was seen from our previous work that gp120/CD4 complexes generate a large fraction of antiCD4 antibodies and hence are unsuitable for vaccination purposes, we generated a construct with the minimal binding region of CD4. The small fragment of CD4 spanning from 21st residue to 64th residue was inserted in the V1/V2 loop of gp120. The insertion site was designed based on the region of gp120 closest to this fragment and capable of tolerating insertions. This protein did not bind to 17b as well as gp120/CD4 complex but showed a higher binding compared to full length gp120. Further immunological characterization with this protein revealed that it was not capable of generating neutralizing antibodies against the virus. Chapter five discusses the design and execution of a SPR based solution phase competition experiment to find the solution phase binding constant of CD4 and CD4 analogs to gp120. A major problem during the analysis of binding data obtained by SPR is the accurate determination of Rmax, a parameter needed to obtain an accurate equilibrium dissociation constant. In this chapter we have developed a binary as well as a ternary solution phase SPR based assay to accurately determine a solution phase equilibrium binding constant. The binding constants were determined for gp120 binding to CD4D12 and other CD4 analogs. To confirm the validity of the assay, a control antigen:antibody interaction whose equilibrium dissociation constant has been determined by other methods has been used as a test case. Chapter six discusses the design and characterization of V3 peptides inserted in the loop regions of E. coli Thioredoxin (Trx). Trx has earlier been used to display random peptide libraries between the 33rd and the 34th residue. We have constructed three constructs where the peptide has been inserted between the 33rd and 34th residue, between the 74th and 75th residue and between the 84th and 85th residue. The insertion between 74th and 75th position (74V3Trx) was found to be superior to the other two and would be a suitable alternative for display of a random peptide library. The binding of these constructs to 447-52D, a V3 peptide specific antibody was characterized. These were also characterized immunologically, and 74V3Trx was found to generate weakly neutralizing activity against the MN strain of HIV-1. Competition experiments with 447-52D with these sera indicated that there were antibodies generated that could compete out 447-52D binding to gp120 but not in sufficient concentration to provide broad neutralization. Appendix 1 discusses the rational design of disulfides to stabilize proteins based on the analysis of naturally occurring disulfides. In our attempts to design a rigidified version of gp120 we had designed disulfides in gp120 based on its crystal structure. Many of these were disulfides that would span antiparallel adjacent strands. In order to improve the design principles, we analyzed naturally occurring disulfides that span antiparallel adjacent strands and characterized them in terms of their positional preference in a beta sheet. It was found that these disulfides mostly occur on edge strands and are found exclusively between non-hydrogen bonded registered pairs of adjacent antiparallel strands. Mutagenesis on Thioredoxin was performed to verify our results. It was found that disulfides designed between the non-hydrogen bonded pairs of antiparallel strands could significantly stabilize the protein whereas the ones between hydrogen bonded pairs destabilized the protein.

L’épidémie du VIH/SIDA a particulièrement touché l’Afrique Sub-Saharienne. En 1998, le gouvernement sénégalais a mis en place une cohorte observationnelle d’adultes infectés par le VIH-1 afin d’évaluer l’impact des antirétroviraux donnés au sein de l’Initiative Sénégalaise d’Accès aux Antirétroviraux (ISAARV). Plus spécifiquement, cette évaluation portait sur l’efficacité clinique et biologique des traitements, leur tolérance clinique et biologique, l’observance et l’émergence de résistances virales. La cohorte ANRS 1215 a été mise en place entre 1998 et 2002 à partir des 404 premiers patients inclus dans l’ISAARV. Cette thèse a utilisé les données recueillies au sein de cette cohorte pour analyser certains aspects de la réponse bio-cliniques aux traitements antirétroviraux en Afrique. Dans la première partie de ce travail, différents aspects de l’infection par le VIH en Afrique Sub-Saharienne et les questions relatives à la réponse bio-cliniques aux traitements antirétroviraux ont été passés en revus. Dans la seconde partie, les aspects méthodologiques de l’analyse des données longitudinales de cohorte ainsi que les problématiques associées ont été étudiés. Enfin, différents aspects de la réponse bio-cliniques après initiation des antirétroviraux ont été analysés au travers de 5 articles portant sur la mortalité précoce, la reconstitution immunologique, la survenue d’évènements classant, la réponse et la tolérance à deux régimes thérapeutiques différents. / Sub-Saharan Africa has been heavily affected by the HIV/AIDS epidemic. In 1998, the Sengalese government launched an observational cohort of HIV-1 infected adults that aimed to assess the impact of antiretroviral therapy (ART) provided by the “l’Initiative Sénégalaise d’Accès aux Antirétroviraux” (ISAARV). This assessment focused more specifically on the clinical and biological effectiveness of ART, on the clinical and biological tolerance and on the emergence of virological resistances. The cohort was made of the first 404 patients included in the ISAARV between 1998 and 2002. The data collected through this cohort have been used to analyse in this work various aspects of biological and clinical answer to ART in Africa. In the first section, different aspects of the HIV/AIDS infection in Sub-Saharan countries have been reviewed with an emphasis put on the remaining bio-clinical questions. In the second, methodological aspects of the analysis of longitudinal data and related questions have been studied. Then, various aspects of the biological and clinical answer to ART have been analysed through five articles about early mortality, immune reconstitution, AIDS-defining illness occurrence, and the effectiveness and tolerance of two regimen.

This research focuses on the psychosocial factors that affect adherence to highly active antiretroviral therapy (HAART) amongst HIV/AIDS patients at Kalafong Hospital. Even though the development of such regimens has helped turn HIV infection in the United States into a relatively manageable, though still serious chronic disease, compliance remains one of the major challenges in managing medication for those patients living with HIV/AIDS. This is particularly relevant given the high adherence rate (95%) required to obtain a successful long-lasting effect. In South Africa non-compliance to HAART is an under-explored phenomenon. Consequently, an understanding of factors influencing compliance is still incomplete. A qualitative study that investigates non-adherence to medication in HIV/AIDS patients was undertaken at Kalafong Hospital. This study aimed to understand patients’ psychosocial difficulties resulting in non-adherence. The study was approached in terms of the health belief model (HBM), which addresses individual characteristics pertaining to change, the transtheoretical change model (TTM) and the motivational interviewing model (MI), which address both individual and social contexts pertaining to change. The findings are designed for use by healthcare professionals as a proactive compliance enhancement tool. Participants were recruited through referrals by the medical staff to the researcher. The criteria included that participants had relapsed due to non-compliance with drug therapy. Participants that were currently experiencing difficulties with adherence were also included in the study. Males and females aged between 20 and 40 were included in the study. Fifteen participants between the ages of 20 and 40 participated in the study (13 females and two males). The data were collected by means of semi-structured interviews and follow-up unstructured questions. The interviews were audio recorded and field notes were taken. Data were analysed qualitatively. Sixteen themes emerged and were further classified into two categories: individual and social context. The themes were then compared and integrated with the literature. The study concludes that psychosocial factors such as support from family, friends and healthcare workers was found to be of utmost importance in encouraging adherence. Medication can only prolong a patient’s life if the psychosocial context in which the patient is embedded is considered in the treatment plan. / Dissertation (MA)--University of Pretoria, 2008. / Psychology / unrestricted

Orientador: Maria Luiza Moretti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-18T15:05:39Z (GMT). No. of bitstreams: 1 Passos_AnaIsabelaMorsch_M.pdf: 2317515 bytes, checksum: 2a34cbc644c6ec0279e1f66cf58ccf4a (MD5) Previous issue date: 2011 / Resumo: A função pulmonar, em pacientes infectados pelo vírus da imunodeficiência humana (HIV), tem sido associada com a redução nos parâmetros de ventilação pulmonar. Métodos: Foi realizado estudo do tipo corte transversal para avaliar a função pulmonar de pacientes com aids atendidos em ambulatórios de doenças infecciosas. Foram avaliados dados de espirometria, pressão inspiratória máxima (PImáx) e pressão expiratória máxima (PEmáx). Também foram coletados, através de prontuários médicos, dados clínicos, demográficos e laboratoriais. Resultados: Os dados de PImáx e PEmáx foram avaliados em 73 pacientes, o exame de espirometria foi avaliado em 54 pacientes. O tempo médio de infecção pelo HIV (em anos) foi semelhante para os homens (8,5 ± 5,1) e mulheres (10,4 ± 4,2, p = 0,13) e o tempo médio de utilização da terapia antiretroviral foi de 8,5 ± 4,1 anos para as mulheres e 7,7 ± 4,1 anos para os homens (p = 0,46). Os valores de PImáx e PEmáx foram abaixo do previsto em 38 (52%) e 25 (34%) pacientes, respectivamente. O uso do tenofovir e a presença de tosse, no momento em que o teste foi realizado, foram independentemente associados com PEmáx abaixo do valor previsto. Valores elevados de creatinoquinase foram associados com o uso prolongado de terapia antiretroviral (9,6 ± 4,1 anos versus 7,4 ± 3,9 anos, p = 0,05). Os valores de capacidade vital forçada (CVF) se apresentaram reduzidos em 14 (26,4%) pacientes e foi independentemente associado com risco cardiovascular intermediário ou alto (p = 0,002) e com murmúrio vesicular reduzido à ausculta pulmonar (p = 0,047). Os valores de volume expiratório forçado no primeiro segundo (VEF1) foram significativamente menores nos pacientes com tempo prolongado de tabagismo (p = 0,019) e risco cardiovascular intermediário ou alto (p = 0,003). A redução da relação VEF1/CVF foi associada com o tabagismo (p = 0,041). Conclusão: Nas medidas de PImáx e PEmáx, 38 (52,1%) e 25 (34,2%) pacientes apresentaram resultados abaixo do previsto. O exame de Espirometria foi considerado normal em 45 pacientes. Houve diagnóstico de distúrbio obstrutivo e restritivo em um (1,9%) e 8 (14,8%) pacientes. O uso de Tenofovir e a presença de tosse foram independentemente associadas à PEmáx abaixo do previsto. Pacientes com menores valores de CVF foram os com maior risco cardiovascular e murmúrio vesicular diminuído à ausculta pulmonar. Pacientes com menores valores de VEF1 foram aqueles com maior tempo de tabagismo e maior risco cardiovascular. A variável independentemente associada a valores reduzidos de VEF1/CVF foi tabagismo / Abstract: Background: Pulmonary function, in HIV infected patients, has been associated with reduction in pulmonary ventilation parameters Methods: We conducted a sectional study to evaluate the pulmonary function of AIDS patients cared for in the infectious diseases ambulatories. Maximal inspiratory (MIP) and expiratory (MEP) pressures and spirometry were assessed. Clinical, demographic and laboratorial data were also evaluated. Results: MIP and MEP were assessed in 73 and spirometry in 54 patients. The mean time of HIV infection (in years) was similar for men (8.5+5.1) and women (10.4±4.2; p= .13) and the mean time of use of antiretroviral therapy (ART) was 8.5±4.1 years for women and 7.7±4.1 years for men (p= .46). MIP and MEP values were not normal in 38 (52%) and 25 (34%) patients, respectively. The use of tenofovir (TVF) and presence of cough, by the time the test was performed, were independently associated MEP below the predictive value. Elevated CK values were associated with prolonged time ARV usage (9.6±4.1 years vs 7.4±3.9 years; p= .05). FVC was reduced in 14 (26.4%) patients and was independently associated with high and/or intermediate cardiovascular risk (p= .002), and those with reduced vesicular murmur in auscultation (p= .047). FEV1 was significantly lower in patients with prolonged time of smoking (p= .019) and high and/or intermediate cardiovascular risk (p= .003). Reduced FEV1/FVC ratio was associated with smoking (p= .041). Conclusions: In measurements of MIP and MEP, 38 (52.1%) and 25 (34.2%) patients had results below forecast. The spirometry test was considered normal in 45 patients. There was a diagnosis of obstructive and restrictive ventilation disorder in one (1.9%) and 8 (14.8%) patients. The use of tenofovir and cough were independently associated with lower than expected MEP. Patients with lower values of FVC had the highest cardiovascular risk and reduced breath sounds on pulmonary auscultation. Patients with lower values of FEV1 were those with longer duration of smoking and increased cardiovascular risk. The variable independently associated with lower values of FEV1/FVC was smoking / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

No description available.

This paper investigates occupational mismatch of highly educated refugees in Sweden and aims to study what factors are impacting their labour market integration process. In contrast to the extensive number of quantitative reports based on registered data in the field, this research applies a qualitative approach by conducting interviews with the target group and incorporating a temporal aspect of the process. The results confirm existing theories such as human capital deficit, lack of social capital and signalling issues, but also indicates that contextual factors, being family demands and financial pressure, affect the process. An openness towards a change of field and lack of guidance from authorities emerged as factors for mismatch too. Lastly, feelings of stress and frustration seems to influence the process to a big extent which leads us to the conclusion that the labour market integration process of educated refugees is highly influenced by the aspect of time - and more specifically the lack of it.

Human immunodeficiency virus (HIV) infection has reached epidemic proportions in South Africa. The availability of highly active anti-retroviral therapy (HAART) prolongs life in HIV-infected persons, who may subsequently present with chronic manifestations of HIV-infection. The respiratory morbidity attendant to HIV-infection, even in the presence of HAART is high, the aftermath of which is lung tissue destruction and bronchiectasis. As a consequence of the political decision not to offer HAART to HIV-infected children, a number of children in South Africa have been left with severe consequences of uncontrolled HIV-infection. Bronchiectasis is one of those and because children with this devastating condition were numerous in the Pretoria region, the author and her colleagues began a Chronic Lung Disease Clinic in that region. This prompted the idea of investigating both the epidemiological profiles of these children and an attempt to intervene with both standard bronchiectasis guideline care and the use of a form of therapy commonly employed in other forms of bronchiectasis. This thesis explores those ideas. Important new and novel findings that were consequent were; that bronchiectasis is diagnosed late in HIV-infected children at a mean age of 6.9 years. The predominant organisms cultured from the airways are Haemophilus influenzae and parainfluenzae in 49% of samples. Pseudomonas aeruginosa (PA), common in cystic fibrosis (CF)-bronchiectasis is an uncommon pathogen in HIV-related bronchiectasis; isolated in only 2% of specimens. Tuberculosis (TB), at least as reported, is a significant antecedent of bronchiectasis, reported in 48.5%of children. A further 21.2% of the patients had received more than two courses of anti-TB treatment. However, proof of TB infection has been lacking. Respiratory morbidity is significant with the mean forced expiratory flow in one second (FEV1) of 53%, in this cohort at the time of presentation. Thirty-six percent of all children were exposed to environmental tobacco smoke, although this was not correlated with disease severity or HIVdisease progression. There is elevation of immunoglobulins in HIV-related bronchiectasis, with a mean IgE of 79 kU/l. This was not, though, associated with HIV disease progression as previously described in adult studies, nor with the presence of allergic bronchopulmonary aspergillosis (ABPA). The elevation in IgE was also not associated with an elevation of T helper-2 mediated cytokines, confirming the lack of association with atopy. The predominant cytokine, identified is interleukin (IL)-8, both systemically and locally (in airway secretions). There was elevation of other T helper-1 driven cytokines, reflecting an ability to mediate adequate inflammatory responses, which was independent of the level of immunosuppression. With the presence of HAART, there was a decline in the pro-inflammatory cytokines over time, which may be attributed to the ongoing effect of HAART that ties in to, or goes beyond the restoration of T cell numbers. Soluble triggering receptor expressed on myeloid cells (sTREM), an innate immune marker, is elevated in children with HIV-related bronchiectasis when compared to a control group of children with cystic fibrosis-related bronchiectasis. sTREM is not associated with the presence of exacerbations and the level of immunosuppression. The use of an anti-inflammatory drug erythromycin also did not impact the sTREM values. There was also no relationship between sTREM and pro and antiinflammatory cytokines and chemokines. Fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) could not reliably predict the presence of pulmonary exacerbations. Its diagnostic value was limited to identifying disease activity in acute pneumonia. 18F-FDG PET also had no significant correlation with CRP, inflammatory cytokines or markers of HIV disease activity. In a randomised controlled trial of erythromycin, a cost-effective immunomodulatory drug, compared to placebo, erythromycin was ineffective in reducing the number of pulmonary exacerbations. Erythromycin also failed to demonstrate any effect on systemic and local pro- and anti-inflammatory cytokines/chemokines. With access to anti-retroviral therapy, airway clearance, nutritional rehabilitation and vigilant follow up there was an improvement in pulmonary function parameters and stability of the degree of bronchiectasis that we propose is probably in keeping with an organ system disease modifying effect that may be, an as yet, undefined and undescribed byproduct of HAART. / Thesis (PhD)--University of Pretoria, 2012. / Paediatrics and Child Health / unrestricted

In the diploma thesis the charge transfer reaction on thin layer N,N',N'',N'''-tetramethyl-tetra-3,4-pyridinoporphyrazinocobalt mediator is studied. The mediator is deposited on electrode surface formed by basal plane of highly ordered pyrolytic graphite. The modified electrode, which displays electrocatalytic activity to oxidation of propylene, has been characterized by cyclic voltammetry, backscattering spectroscopy and atomic force microscopy.

Inorganic alternating current electroluminescent devices (AC-ELs) are known for their ruggedness and extreme long-term reliability, which is why they can often been found in industrial and medical equipment as well as in applications in the military sector. In contrast to the inorganic phosphors used in AC-ELs, organic materials offer a number of advantages, in particular a significantly higher efficiency, easier processibility, and a wide selection of emitter materials spanning the entire visible spectrum. Several efforts towards alternating current driven organic light-emitting devices have recently been made, however, important operating mechanism are still not well understood. In the first part of this theses, alternating current driven, capacitively coupled, pin-based organic light-emitting devices are investigated with respect to the influence of the thickness of the insulating layer and the intrinsic organic layer on the driving voltage. A three-capacitor model is employed to predict the basic behavior of the devices and good agreement with the experimental values is found. The proposed charge regeneration mechanism based on Zener tunneling is studied in terms of field strength across the intrinsic organic layers. A remarkable consistency between the measured field strength at the onset point of light emission (3–3.1 MV/cm) and the theoretically predicted breakdown field strength of around 3 MV/cm is obtained. The latter value represents the field required for Zener tunneling in wide band gap organic materials according to Fowler-Nordheim theory. In a second step, asymmetric driving of capacitively coupled OLEDs is investigated. It is found that different voltages and/or pulse lengths for positive and negative half-cycle lead to significant improvements in terms of brightness and device efficiency. Part two of this work demonstrates a device concept for highly efficient organic light-emitting devices whose emission color can be easily adjusted from, e.g., deep-blue through cold-white and warm-white to saturated yellow. The presented approach exploits the different polarities of the positive and negative half-cycles of an alternating current driving signal to independently address a fluorescent blue emission unit and a phosphorescent yellow emission unit vertically stacked on top of each other. The electrode design is optimized for simple fabrication and driving and allows for two-terminal operation by a single source. The presented approach for color-tunable OLEDs is versatile in terms of emitter combinations and meets application requirements by providing a high device efficiency of 36.2 lm/W, a color rendering index of 82 at application relevant brightness levels of 1000 cd/m², and warm-white emission color coordinates. The final part demonstrates an approach for full-color OLED pixels that are fabricated by vertical stacking of a red-, green-, and blue-emitting unit. Each unit can be addressed separately which allows to efficiently generate every color that is a superposition of spectra of the individual emission units. The device is built in a top-emission geometrywhich is highly desirable for display fabrication as the pixel can be directly deposited onto the back-plane electronics. Furthermore, the presented device design requires only three independently addressable electrodes which simplifies fabrication and electrical driving. The electrical performance of each individual unit is on par with standard pin single emission unit OLEDs, showing very low leakage currents and achieving high brightness levels at moderate voltages of around 3–4 V.

Brain drain, or human capital flight, is a phenomenon which represents a society-wide problem in the post-Dayton Bosnia and Herzegovina (BiH). At present, more than half of the people claiming BiH nationality live abroad, out of which a significant part possesses tertiary education. Loss of human capital carries negative socio-economic consequences which hinder the country's development. On the other hand, brain gain, i.e. return of highly skilled migrants to their country of origin, might reverse some of the unfavourable effects. Nevertheless, the phenomenon of the return of highly skilled migrants remains under researched not only within the region of the Western Balkans, but also on a global scale. Although this type of migration has increasingly attracted the attention of many scholars from various academic and non- academic fields, contemporary literature on this topic suffers from limitations and tends to oversimplify the returnees' motivations to purely economic incentives. This study attempts to describe the complex factors leading the highly skilled migrants to return to BiH. Based on the 33 respondents' subjective preferences from the spheres of career, family and lifestyle, this work provides an insight into the decisions of returnees in the context of the developing Western Balkan country.