Sickle Cell Disease (SCD) is a genetic disorder that affects approximately 1 out of every 600 African-American newborns (NHLBI, 2006). Research suggests that caregivers of children with SCD are at risk for maladjustment. The purpose of this current study was to build upon previous research regarding stress and coping of parents of children with SCD. Additionally, novel information regarding the effects of racial identity was explored. Participants included 103 caregivers (M = 41.1 years old, SD = 8.04 years) of children with SCD. Parents completed a demographic form, the Brief Symptom Inventory-18, Pediatric Inventory for Parents, Coping Health Inventory for Parents, and the Multidimensional Inventory of Black Identity. Results revealed that increases in caregiver stress associated with parenting a chronically ill child were accompanied by increases in caregiver psychosocial maladjustment. Caregiver coping did not significantly predict functioning nor moderate the stress-adjustment relation. Exploratory analysis revealed significant associations between parents’ racial identity and parenting stress.

This dissertation thesis consists of a series of chapters that are interwoven by solving interesting biological problems, employing various computational methodologies. These techniques provide meaningful physical insights to promote the scientific fields of interest. Focus of chapter 1 concerns, the importance of computational tools like docking studies in advancing structure based drug design processes. This chapter also addresses the prime concerns like scoring functions, sampling algorithms and flexible docking studies that hamper the docking successes. Information about the different kinds of flexible dockings in terms of accuracy, time limitations and success studies are presented. Later the importance of Induced fit docking studies was explained in comparison to traditional MD simulations to predict the absolute binding modes. Chapter 2 and 3 focuses on understanding, how sickle cell disease progresses through the production of sickled hemoglobin and its effects on sickle cell patients. And how, hydroxyurea, the only FDA approved treatment of sickle cell disease acts to subside sickle cell effects. It is believed the primary mechanism of action is associated with the pharmacological elevation of nitric oxide in the blood, however, the exact details of this mechanism is still unclear. HU interacts with oxy and deoxyHb resulting in slow NO production rates. However, this did not correlate with the observed increase of NO concentrations in patients undergoing HU therapy. The discrepancy can be attributed to the interaction of HU competing with other heme based enzymes such as catalase and peroxidases. In these two chapters, we investigate the atomic level details of this process using a combination of flexible-ligand / flexible-receptor virtual screening (i.e. induced fit docking, IFD) coupled with energetic analysis that decomposes interaction energies at the atomic level. Using these tools we were able to elucidate the previously unknown substrate binding modes of a series of hydroxyurea analogs to human hemoglobin, catalase and the concomitant structural changes of the enzymes. Our results are consistent with kinetic and EPR measurements of hydroxyurea-hemoglobin reactions and a full mechanism is proposed that offers new insights into possibly improving substrate binding and/or reactivity. Finally in chapter 4, we have developed a 3D bioactive structure of O6-alkylguanine-DNA alkyltransferase (AGT), a DNA repair protein using Monte Carlo conformational search process. It is known that AGT prevents DNA damage, mutations and apoptosis arising from alkylated guanines. Various Benzyl guanine analouges of O6- methylguanine were tested for activity as potential inhibitors. The nature and position of the substitutions methyl and aminomethyl profoundly affected their activity. Molecular modeling of their interactions with alkyltransferase provided a molecular explanation for these results. The square of the correlation coefficient (R2 ) obtained between E-model scores (obtained from GLIDE XP/QPLD docking calculations) vs log(ED)values via a linear regression analysis was 0.96. The models indicate that the ortho-substitution causes a steric clash interfering with binding, whereas the meta-aminomethyl substitution allows an interaction of the amino group to generate an additional hydrogen bond with the protein. Using this model for virtually screening studies resulted in identification of seven lead compounds with novel scaffolds from National Cancer Institute Diversity Set2.

Cells often exist in heterogeneous mixtures. Density provides a property to separate several types of cells from the mixed sample in which they originate. Density-based separation methods provide a standard method to quickly separate or enrich specific populations of cells, such as lymphocytes from whole blood. This dissertation explores the use of aqueous multiphase systems (AMPS) as self-forming step-gradients in density for the separation of cells. AMPS were first discovered over a hundred years ago as aqueous two-phase systems. Density as a tool to separate cells is at least as old. Despite this long history, the work in this thesis is the first work to use AMPS to perform density-based separations on cells. This combination provides a powerful technique to separate cells and enable new testing at the point-of-care. Chapter 1 provides a short overview of aqueous multiphase systems and density-based separations of cells. Chapter 2 describes the process of taking technology, including AMPS, from a demonstration in a laboratory to a large scale evaluation in a field setting. In Chapter 3 and Appendix I, AMPS provide a means to enrich reticulocytes from whole blood as a means to grow malaria parasites. Chapter 4 and Appendix II describe the development and proof-of-prinicple of a density-based diagnostic test for sickle cell disease (SCD) using AMPS. Chapter 5 and Appendix III detail the results of a large scale field evaluation of a rapid test for SCD using AMPS in Zambia. Demonstrations of AMPS for density- and size-based separations are provided in Appendices IV and V. Appendix VI demonstrates the general usefulness of density to separate crystal polymorphs with another density-based separation method: magnetic levitation in a paramagnetic fluid. Beyond density, novel combinations of technology, such as electrochemistry and telecommunications provide opportunities for enabling global health (Appendix VII). / Engineering and Applied Sciences

Pregnancy in women with hemoglobinopathy has been associated with an increased risk of adverse pregnancy outcomes. We conducted a historical cohort study using Discharge Abstract Database for the fiscal year 1991-1992 through 2007-2008. We estimated the frequency of pregnant women with hemoglobinopathy and examined their associations with adverse pregnancy outcomes. Women with sickle cell disease are more likely to develop pre-eclampsia and preterm labor, and to undergo cesarean delivery than women with nutritional deficiency anemia, suggesting that there are other mechanisms beyond anemia that may be responsible for an increased risk of adverse pregnancy outcomes. The data suggested a synergistic effect of hemoglobinopathy and pre-eclampsia on preterm labor and cesarean delivery. Prediction models for pre-eclampsia, preterm labor and cesarean delivery were created and internally validated for women with hemoglobinopathy, with satisfactory discrimination and calibration.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed Feb. 13, 2009). Includes bibliographical references.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 13, 2008). Includes bibliographical references (p. 174-183).

Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2006. / Dr. Peter A. Lane, Committee Member ; Dr. Larry V. McIntire, Committee Member ; Dr. Ronald W. Rousseau, Committee Member ; Dr. James R. Eckman, Committee Member ; Dr. Timothy M. Wick, Committee Chair.

Orientador: Eduardo Alves de Almeida / Coorientador: Claudia Regina Bonini Domingos / Banca: Gustavo Orlando Bonilla Rodriguez / Banca: Dorotéia Rossi Silva Souza / Resumo: A anemia falciforme (AF) apresenta fisiopatologia que envolve múltiplas alterações nos eritrócitos falcêmicos, episódios vasoclusivos, hemólise, ativação de mediadores inflamatórios, disfunção das células endoteliais e estresse oxidativo. Estes eventos dificultam o tratamento e culminam no desenvolvimento de manifestações como anemia, crises de dor e insuficiência de múltiplos órgãos. Portanto, o presente estudo objetivou, em portadores da AF, avaliar marcadores do estresse oxidativo e da capacidade antioxidante, correlacionando-os ao tratamento com hidroxiureia (HU), aos haplótipos da β-globina e aos polimorfismos da glutationa S-transferase (GSTT1, GSTM1 e GSTP1), em comparação com os resultados do grupo controle (GC). Os grupos estudados se compuseram de 48 indivíduos sem hemoglobinopatias (GC), pacientes com AF tratados com HU [AF (+HU), n=13] e pacientes não tratados [AF (-HU); n=15], após consentimento informado. Para a composição dos grupos utilizamos métodos citológicos, eletroforéticos, cromatográficos, moleculares e informações de prontuários. A pesquisa dos polimorfismos de GSTM1 e GSTT1 foi realizada por meio de PCR-MULTIPLEX, enquanto o polimorfismo GSTP1 por PCR-RFLP. Os parâmetros bioquímicos foram avaliados por meio de métodos espectrofotométricos [TBARS, TEAC, atividade das enzimas catalase (CAT) e GST] e cromatográficos [glutationa (GSH)]. Os níveis de Hb Fetal (Hb F) verificados no grupo AF (+HU) (10,9%) confirmaram seu já bem descrito efeito farmacológico da HU, porém, o grupo AF (-HU) também apresentou níveis elevados de Hb F (6,1%) que podem ter sido influenciados por fatores genéticos não considerados neste estudo. Encontramos maior frequência do haplótipo Bantu (48,2%), seguido pelo Benin (32,1%) e, também, haplótipo Camarões... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sickle cell anemia (SCA) shows a pathophysiology that involves multiple changes in the sickle cell erythrocytes, vaso-occlusive episodes, hemolysis, activation of inflammatory mediators, endothelial cell dysfunction and oxidative stress. These events complicate the treatment and culminate in the manifestations development such as anemia, pain crises and multiorgan dysfunction. Therefore, the aim of this study was to evaluate, in SCA patients, oxidative stress and antioxidant capacity markers, correlating them to treatment with hydroxyurea (HU), the β-globin haplotypes and glutathione S-transferase polymorphisms (GSTT1, GSTM1 and GSTP1) in comparison to a control group (CG). The groups were composed of 48 individuals without hemoglobinopathies (CG), SCA patients treated with HU [AF (+ HU), n = 13] and untreated patients [AF (-HU), n = 15], after informed consent . For the groups composition we used cytological, electrophoretic, chromatographic and molecular methods and information from medical records. The GSTM1 and GSTT1 polymorphisms study was performed by multiplex PCR, while the GSTP1 polymorphism by PCR-RFLP. Biochemical parameters were measured using spectrophotometric methods [TBARS, TEAC and catalase (CAT) and GST activities] and chromatographic method [glutathione (GSH)]. The Fetal Hb (Hb F) levels observed in the SCA (+HU) group (10.9%) confirmed their already welldescribed pharmacological effect of HU, however, the SCA (-HU) group also had high Hb F levels (6.1%) that may have been influenced by genetic factors not targeted in this study. We found a higher frequency of Bantu haplotype (48.2%), followed by Benin (32.1%) and also Cameroon haplotype, rare in our population and 19.7% of atypical haplotypes. The Bantu haplotype presence was related to higher lipid peroxidation levels in patients, but also, it confered the differential response to HU treatment... (Complete abstract click electronic access below) / Mestre

Haemoglobinopathies, which include sickle-cell anaemia (SCA) and α- and β-thalassaemia, represent some of our few unequivocal examples of human evolution. The underlying genetic mutations reflect a recurring adaptation against one of the biggest infectious disease killers of humans, Plasmodium falciparum malaria. Inheritance of one copy of a sickle-cell or thalassaemic allele leads to protection against death from malaria, while two copies can result in a severe blood disorder. As a result, haemoglobinopathies have risen in frequency through balancing selection and pose a significant public health problem in parts of the world with a history of malaria transmission. Their study therefore lies at the interface between evolutionary biology and public health. In this thesis, I explore different aspects of the epidemiology and population genetics of haemoglobinopathies around the world. Using pre-existing epidemiological data, statistical and geostatistical methods and Geographic Information System tools, I develop detailed evidence-based maps of the α-thalassaemia allele frequency distribution and genetic diversity in Southeast Asia and sickle-cell allele frequency in India. Pairing these with birth data, I generate sub-national estimates of the number of newborns born with severe forms of α-thalassaemia and SCA in Thailand and India, respectively, together with uncertainty estimates. In addition, I use a flexible population genetic simulation model to explore evolutionary explanations for the contrasting spatial haplotype patterns observed for SCA and the severe form of β-thalassaemia (β0-thalassaemia) in sub-Saharan Africa and the Middle East, and resurrect a 20-year old question surrounding the genetic origin of sickle-cell. Understanding the fine-scale geographical heterogeneities in the distributions of malaria-protective haemoglobinopathies is critical for addressing basic science questions and applied public health queries. Working at the interface between evolutionary biology and public health has provided me with the opportunity to build a more complete overview of the neglected increasing public health burden that this group of human disorders represents.

This thesis explores communication with children affected by sickle cell disease about their condition from the perspectives of both children and parents. It includes three papers: A literature review, an empirical paper and a critical appraisal. Papers one and two have been prepared for submission to Social Science and Medicine and Qualitative Health Research, respectively. Paper one is a meta-synthesis of qualitative literature investigating experiences of communication from the perspective of children with sickle cell disease. A systematic literature search revealed nine relevant papers, which were synthesised by extracting findings related to communication about sickle cell disease. Children were found to receive inconsistent messages about their condition from different personal and professional groups. Communication about the prognosis of sickle cell disease and the social acceptability of the condition differed across the groups. The implications for children's understandings of their condition and their adjustment are discussed. Paper two presents an empirical study of parental communication experiences with children affected by sickle cell disease. Twelve interviews were conducted and subject to inductive thematic analysis which was applied within a contextualist epistemological framework. Parents described skills in 'coaching' their child to negotiate the various challenges associated with managing sickle cell disease. They also described ways in which they avoided challenging topics of communication such as inheritance, the risk of comorbid disease and the life-long nature of the condition. The findings suggest a need for healthcare professionals to support parents in overcoming barriers to talking about difficult topics. This may facilitate more consistent communication between parents and professionals, which has implications for improving child wellbeing and adjustment. Paper three is a reflective piece and is not intended for publication. It critically evaluates papers one and two and discusses the joint implications of the findings for research and clinical practice. Reflections on the experience of conducting a meta-synthesis and an empirical qualitative study are offered in the context of personal and professional development.