O objetivo deste estudo foi avaliar a evolução do estado nutricional, a ingestão alimentar por via oral (VO) e a utilização de terapias nutricionais complementares durante a internação de crianças e adolescentes submetidos ao transplante de células-tronco hematopoéticas (TCTH) alogênico em um hospital terciário. Estudo retrospectivo, com revisão de prontuários de pacientes submetidos ao TCTH, com idade entre 0 e 19 anos incompletos, entre janeiro de 2009 e dezembro de 2014. Foram coletados dados referentes a dados antropométricos, ingestão alimentar por VO, terapias nutricionais utilizadas (nutrição enteral (NE) e/ou parenteral (NP)); e sinais e sintomas clínicos em seis momentos: Internação, D0 (dia da infusão de células), D+7, D+14, D+21 e D+ 28. Foram avaliados 63 pacientes, 56% do sexo masculino, com uma mediana de idade de 10 anos. No momento da internação 100% dos pacientes tiveram suas necessidades energéticas atingidas pela VO, diminuindo a partir do D0 (cerca de 30%), com maior prevalência de utilização de NP e NE a partir do D+7. Inapetência, mucosite e náusea foram os sinais e sintomas mais frequentes. A partir do D+21 foi possível observar um aumento do aporte calórico por VO. Os pacientes apresentaram diminuição da ingestão alimentar ao longo da internação, porém, neste hospital, já se está conseguindo atingir um aporte calórico mais próximo do ideal, com auxílio de terapias nutricionais complementares. / The aim of this study was to describe the nutritional aspects relevant to the maintenance of a nutritional status during hospitalization of children and adolescents undergoing allogeneic hematopoietic stem cell transplantation (HSCT) at a tertiary hospital. A retrospective study with a review of medical records of patients undergoing HSCT, aged between 0 and 19 years of age (incomplete) between January 2009 and December 2014. Data were collected regarding food intake, nutritional therapies used, and clinical signs and symptoms in six times: Hospitalization, D0 (day of cell infusion), D+7, D+14, D+21 and D+28. Sixty-three patients were evaluated, being 56% males, with a median age of 10 years. At the time of hospitalization, 100% of patients had their energy needs met by mouth, decreasing from D0 (about 30%), with more prevalent use of PN (parenteral nutrition) and EN (enteral nutrition) from D+7. Loss of appetite, mucositis and nausea were the most frequent signs and symptoms. From D+21 it was possible to observe an increase in caloric intake by mouth. Patients showed decreased food intake throughout hospitalization, but in this hospital it has been already possible to get calorie intake closer to the ideal one with the help of complementary nutritional therapies.

Foram analisados 106 pacientes portadores de Linfoma de Hodgkin (LH) com recidiva da doença ou refratários ao tratamento inicial que foram submetidos ao transplante autólogo de células tronco hematopoiéticas (TCTH), na ordem consecutiva de sua realização, entre o mês de abril de 1993 a dezembro de 2007 em um único Centro Brasileiro: o Serviço de Transplante de Medula Óssea da FMUSP. O grupo teve a mediana etária de 28 anos, 55 pacientes (51,9%) eram do sexo masculino e houve predomínio da raça branca (87,6%). A mediana de seguimento clínico foi de 56,4 meses. Todos pacientes foram submetidos no pré TCTH a protocolos de tratamento convencionais, sendo que o uso dos protocolos MOPP, ABVD e sua associação foram utilizados em 97 pacientes (91,5%). Os pacientes foram classificados, de acordo com a resposta ao tratamento utilizado antes do TCTH, sendo 38,1% considerados refratários e 61,9% responsivos. Dos responsivos, 54 pacientes estavam em segunda remissão completa (85%). Tratamento com quimioterapia em alta dose pré TCTH foi feito em 45 (42,4%) dos pacientes (salvamento). A mobilização das células tronco hematopoiéticas foi realizada com ciclofosfamida 120 mg/kg dividida em dois dias seguido de fator estimulador de colônias de granulócitos (G-CSF) na dose de 6 a 17 mcg/kg em 83 (78%) pacientes. Em 25 pacientes (22%) houve falha de mobilização e a coleta foi realizada por múltiplas punções da medula óssea em centro cirúrgico. O valor mediano de células CD 34 coletadas foi de 2,6 x 106 células CD34/Kg de peso do paciente. Os condicionamentos mais utilizados foram BEAM e CVB, e não se encontrou diferença na sobrevida em relação ao regime empregado (p=0,17). A mediana de enxertia das células transplantadas foi de 12 dias. A sobrevida global após o TCTH pelo método de Kaplan-Meier foi, respectivamente, de 86% e 70% aos 5 e 10 anos. Não influenciaram a sobrevida na análise univariada o sexo, o estadio da doença e a presença de massa tumoral extensa. O principal fator preditivo de melhor sobrevida foi a presença de resposta a quimioterapia pré TCTH (p=0,0095) e hemoglobina maior que 10g/dL ao diagnóstico (p=0,0229). A mortalidade relacionada ao procedimento até o centésimo dia após o TCTH foi de 3,74%, e a principal causa de mortalidade tardia após TCTH foi a recidiva da doença / The study enrolled 106 patients with classic Hodgkin disease (HD) refractory or relapsed after initial treatment who underwent to autologous hematopoietic stem cell transplantation (HSCT) between April 1993 and December 2007. Median age was 28 years and 55 (51,9%) patients were male. Ninety three (87,6%) of patients were white. All patients underwent to conventional chemotherapy protocols prior HSCT. The use of MOPP, ABVD protocols and their associations were used in 97 (91,5%) of the patients. Disease classification was done according to the response to initial treatment and comprised 38,1% refractory and 61,9% responsive patients. In the group of responsive, 54 (85%) patients were in second complete remission. High dose chemotherapy prior HSCT was done as salvage in 45 (42,4%) patients. Stem cell mobilization was done after cyclophosphamide 120mg/kg divided in two days. Granulocyte-colony stimulating factor (G-CSF) 617 mcg/kg was given after cyclophosphamide in 83 (78%) patients. Twenty five (22%) patients failed the mobilization and stem cell harvest was done by bone marrow aspirations. The median number of CD34 collected was 2.6 x 106/L. Preparative regimen mostly used comprised BEAM and CVB and no differences was observed in overall survival (p=0.17). Median time to engraftment was 12 days. Median time of follow-up was 56.4 months. The overall survival (OS) was calculated by the Kaplan-Meier method and was 86% and 70% at 5 and 10 years, respectively. In the univariate analysis, response to initial treatment (p=0.009) and hemoglobin greater than 10g/dL at the time of diagnosis (p=0.02) were factors that influenced better OS. The gender, stage of disease and presence of bulky disease were not significant regarding OS in the univariate analysis. Treatment-related mortality (TRM) in 100-days was 3.74%. The major cause of late mortality was relapse of the disease

O bussulfano (BU) e a ciclofosfamida (CY) são fármacos utilizados nos regimes de condicionamento pré-transplante de células tronco hematopoéticas (TCTH). O BU apresenta estreito intervalo terapêutico, alta variabilidade interindividual na farmacocinética e graves reações adversas. O presente estudo avaliou a administração de uma dose teste de BU oral para a individualização do regime de dosagem, definiu o melhor tempo de coletas esparsas para o monitoramento terapêutico do BU e validou um algoritmo baseado em modelo compartimental e farmacocinética populacional em pacientes submetidos ao TCTH. Trinta pacientes portadores de doenças hematológicas tiveram o tratamento com BU individualizado baseado em uma dose teste oral de 0,25 mg/Kg de BU. As doses foram baseadas no clearance aparente calculado na dose teste e as concentrações plasmáticas foram confirmadas após a quinta dose de tratamento. Os coeficientes de variação obtidos entre os valores de clearance avaliados na dose teste e na quinta dose foram <= 30%, exceto para 5 pacientes. Não foram observadas associação entre os parâmetros farmacocinéticos do BU e a evolução clínica dos pacientes. Com a finalidade de estimar os melhores tempos de coletas ideais para aplicação no monitoramento terapêutico do BU, um modelo farmacocinética populacional foi utilizado e um esquema de coletas esparsas com não mais de cinco amostras por paciente (t = 0,5; 2,25; 3; 4 e 5 horas após a dose) demonstrou ser suficiente para a caracterização da farmacocinética do BU. O presente estudo avaliou também a farmacocinética dos enantiômeros da ciclofosfamida (CY) e seus metabólitos (4-hidroxiciclofosfamida e carboxiciclofosfamida), em pacientes submetidos ao TCTH. Foram investigados pacientes portadores de esclerose sistêmica (n=10) e esclerose múltipla (n=10) em regime de condicionamento com 50 mg CY /kg/dia durante 4 dias. Dois ensaios específicos baseados na análise por LC-MS/MS foram desenvolvidos e validados para analisar os enantiômeros da CY e seus metabólito 4- hidroxiciclofosfamida (HCY) e carboxiciclofosfamida (CEPM) em plasma humano. Os parâmetros farmacocinéticos dos enantiômeros da CY e seus metabólitos foram calculados empregando o programa WinNonlin e mostraram acúmulo plasmático dos enantiômeros (S)- (-)-CY (AUC 215, 0 vs 186,2 ?g.h/mL para os paciente EM e 219,1 vs 179,2 ?g.h/mL para os paciente ES) e HCY (1), provavelmente o (R)-(+)-HCY (AUC 5,6 vs 3,7 ?g.h/mL para os paciente EM e 6,3 vs 5,6 ?g.h/mL para os paciente ES) em ambos os grupos de pacientes investigados. A disposição cinética do metabólito CEPM não mostrou enantiosseletividade. A farmacocinética da CY e seus metabólitos HCY e CEPM não diferiu entre os pacientes portadores de EM ou ES. Não foi observado correlação entre o metabolismo da CY e os genótipos avaliados (CYP2B6 e CYP2C9). Não foi possível correlacionar os valores de AUC0-? dos enantiômeros da CY e/ou dos metabólitos HCY e CEPM com a toxicidade ao uso de CY em virtude do pequeno número de pacientes investigados. / Busulfan (BU) and cyclophosphamide (CY) are drugs used during conditioning treatment for hematopoietic stem cell transplantation (HSCT). BU presents narrow therapeutic window, high interindividual variability in the pharmacokinetics and serious adverse effects. The present study evaluated the administration of a BU test dose for dose individualization, set the best sparse sampling scheme for BU therapeutic monitoring and validated an algorithm based on compartmental and population pharmacokinetics model in HSCT patients. Thirty patients received BU individualized treatment based on an oral test dose of 0.25 mg/kg. Doses were based on apparent clearance calculated with BU test dose. Plasma concentrations were confirmed after the fifth treatment dose. Coefficients of variation obtained between the clearance values evaluated in the test dose and fifth dose were <= 30%, except for 5 patients. No association between BU pharmacokinetic parameters and clinical outcome was observed. To estimate the ideal sampling scheme for BU therapeutic drug monitoring, a population pharmacokinetic model was used. Sparse sampling scheme with no more than five samples per patient (t = 0.5, 2.25, 3, 4 and 5 hours after dosing) was shown to be sufficient to characterize the BU pharmacokinetics. This study also evaluated the pharmacokinetics of the cyclophosphamide enantiomers and its metabolites (4-hydroxycyclophosphamide and carboxicyclophosphamide) in HSCT patients. We investigated patients with systemic sclerosis (SS) (n = 10) and multiple sclerosis (MS) (n = 10) in the conditioning regimen with CY 50 mg/kg/day for 4 days. Two specific tests based on LC-MS/MS analysis were developed and validated to analyze the CY enantiomers and its metabolite 4-hydroxycyclophosphamide (HCY) and carboxicyclophosphamide (CEPM) in human plasma. Pharmacokinetics of CY enantiomers and its metabolites were calculated using WinNonlin software and showed plasma accumulation of (S)-(-)-CY (AUC 215.0 vs 186.2 ?g.h/mL for the MS patient and 219.1 vs. 179.2 ?g.h/mL for the SS patient) and HCY (1), probably the (R)-(+)-HCY (AUC 5.6 vs 3.7 ?g.h /mL for MS patients and 6.3 vs 5.6 ?g.h/ mL for the SS patients) enantiomers in both groups of investigated patients. CEPM kinetics disposition showed lack of enantioselectivity. The pharmacokinetics of CY and its metabolites (HCY and CEPM) did not differ between patients with MS or SS. There was no correlation between the metabolism of CY, CYP2B6 and CYP2C9 genotypes. It was not possible to correlate the AUC0-? of CY enantiomers and/or its metabolites (HCY and CEPM) with CY toxicity due to the small number of patients investigated.

Despite the relatively large number of parents with cancer, relatively little is known about the extent to which having cancer affects the parenting experience. Qualitative studies have identified issues and concerns that create distress among parents with cancer, but quantitative studies have yet to be conducted. Studies demonstrate that parents with cancer experience psychological distress, and that parenting self-efficacy is related to psychological distress among parents without cancer. However, no study to date has examined the relationships between parenting self-efficacy and psychological distress among parents with cancer. This study sought to address these gaps in the literature by comparing parents with cancer to parents without cancer on measures of parenting self-efficacy and psychological distress. It was hypothesized that cancer patients would report lower parenting self-efficacy and higher levels of psychological distress than parents without cancer. This study also sought to explore whether parenting or general self-efficacy mediated the relationship between cancer status and psychological distress. A sample of 57 patients who had been diagnosed with cancer and undergone hematopoietic stem cell transplantation (HSCT), and a control group of 57 parents with no history of cancer were recruited for participation in the study. Patients were recruited during routine outpatient visits or by mail, and controls were recruited using community outreach. Medical record reviews were conducted to assess clinical variables, and participants filled out a standard demographic questionnaire as well as self-report measures of parenting self-efficacy, general self-efficacy, and psychological distress. As hypothesized, results demonstrated that parents with cancer reported less parenting self-efficacy, and more psychological distress than controls (all p-values < .05). Furthermore, findings indicated that both parenting self-efficacy and general self-efficacy mediated the relationship between cancer status and psychological distress. This study fills several gaps in the quantitative literature on parenting with cancer, and suggests that both parenting and general self-efficacy are possible targets for interventions seeking to lessen distress among parents with cancer. Future research should use matched case-control designs to examine longitudinal relationships between parenting self-efficacy and psychological distress, and empirically evaluate interventions aimed at improving parenting and general self-efficacy.

Hematopoietic stem cells (HSCs) that function to maintain the hematopoietic compartment through self-renewal and differentiation capacities, as well as their downstream progeny, are susceptible to transformation resulting in the generation of the leukemic stem cell (LSC). Chief in the factors that control HSC regulation and protection of the HSC compartment is the cellular redox environment. Deregulation of the Hematopoietic Stem/Progenitor Cell (HSPC) redox environment results in loss of HSPC function and exhaustion. The characteristic developments of HSPC exhaustion via exposure to redox stress closely mirror phenotypic traits of hematopoietic malignancies, presenting the HSPC/LSC redox environment as a potential therapeutic target. While myelosuppression and HSPC exhaustion are detrimental side effects of classical chemotherapies, new approaches that differentially modify the HSPC/LSC redox environment may demonstrate LSC cytotoxicity while offering protection of normal HSPC function via differential activation of internal signaling pathways. Precisely how the redox environment and downstream signaling events are affected by these treatments remains unclear; thus highlighting the need for robust methods that evaluate the HSPC/LSC redox state. Because the glutathione (GSH), glutathione disulfide (GSSG) redox couple heavily contributes to the management of HSPC function and redox environment, characterizing the GSH/GSSG redox potential at the HSPC level would provide great insight for therapeutic opportunities. However, accurate measurement the GSH/GSSG redox potential within HSPCs/LSCs has been difficult due to their inherently low numbers. Here, we describe the development and validation of a sensitive method used for the direct and simultaneous quantitation of both oxidized and reduced GSH via LC-MS/MS. We use these methodologies to establish a difference in GSH-GSSG half-cell reduction potentials between normal and malignant HSPCs and examine the therapeutic effect of a redox active MnSOD mimetic, Mn(III) mesotetrakis (N-n-butoxyethylpyridinium-2yl) porphyrin, MnTnBuOE-2-PyP5+ (MnP), within these populations in vitro as well as within a human xenograft model in vivo. MnP demonstrates significant cytotoxic effects in several malignant models, while inducing an opposite cytoprotective effect in normal HSPC populations. The GSH/GSSG redox balance, specifically managed by glutathione reductase activity, is identified as a determining factor of MnP efficacy in various malignant populations. Treatment of the human myelodysplastic cell line (MDSL) offers mechanistic insights into MnP efficacy through hydrogen peroxide mediated activation of activator protein 1 (AP-1) signaling. We identify the redox dependent activation of JunB, a known regulator of normal myeloid lineage HSC proliferation, as a transcriptional mechanistic mediator of MnP treatment induced AP-1 signaling resulting in malignant cytotoxicity. The development of this novel method allowing for the identification of targetable differences between normal and malignant cell populations has provided insight to the underpinnings of potential redox based therapies. Additionally, the finding that MnP can target varying cellular redox states and exert selective cytotoxicity in malignant over normal populations by re-gaining lost control of AP-1 signaling demonstrates the potential for development of safe therapeutics within a variety of clinical applications.

O transplante autólogo de células-tronco hematopoéticas (TACTH) é efetivo para o tratamento da esclerose sistêmica (ES), com controle do acometimento pulmonar, e melhora da fibrose cutânea, da qualidade de vida e aumento da sobrevida global, quando comparado a pacientes não transplantados. Neste tratamento, utiliza-se ciclofosfamida em altas doses, uma droga imunossupressora associada a cardiotoxicidade, potencialmente fatal. A avaliação de potenciais fatores de risco e monitorização clínica durante o procedimento podem contribuir para identificar precocemente a lesão cardíaca aguda e, assim, melhorar o desfecho clínico do paciente. O objetivo deste estudo foi identificar a ocorrência de disfunções cardíacas e avaliar os fatores de risco clínicos e laboratoriais para o desenvolvimento de toxicidade cardíaca aguda induzida pela ciclofosfamida, em pacientes com ES submetidos ao TACTH. Trata-se de um estudo longitudinal e prospectivo, conduzido no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, em pacientes com ES com idade superior a 18 anos, no período de novembro de 2016 a maio de 2018, aprovado por Comitê de Ética em Pesquisa. Os pacientes foram avaliados quanto aos dados clínicos e laboratoriais, incluindo dosagem de peptídeo natriurético, no período pré, durante e 6 meses após o transplante. Foram incluídas 16 mulheres com ES, das quais uma optou por descontinuar a participação no estudo, tendo seus dados excluídos. Nenhum dos participantes apresentava história de uso de substâncias psicoativas ou diagnóstico de diabetes mellitus. Uma paciente era tabagista passiva e uma era tabagista ativa há 24 anos, abstinente desde há três meses antes do início do transplante. Duas pacientes eram hipertensas, controladas com medicamentos anti-hipertensivos. Durante o transplante, 7 (46,7%) pacientes apresentaram alterações cardíacas associadas à ciclofosfamida. As pacientes apresentaram taquicardia, ganho ponderal, aumento de pressão venosa central e dispneia iniciados em menos de 24 horas e até 4 dias após o término da infusão da dose total de ciclofosfamida (200mg/kg) do transplante. Em três, de cinco pacientes submetidas a ecocardiografia, foram detectadas alterações sugestivas de disfunção cardíaca, corroborando os achados clínicos. Uma paciente evoluiu com choque refratário e posterior óbito por falência múltipla de órgãos. Uma paciente necessitou de pericardiocentese de alívio e, nos demais, o manejo com medicações reverteu as alterações clínicas. A dosagem dos níveis séricos de peptídeo natriurético mostrouse mais elevada (p<0,0005) nos pacientes que apresentaram sinais de toxicidade cardíaca. Concluímos que as avaliações clínicas sistematizadas por equipe de enfermagem permitiram a detecção de disfunções cardíacas pós-infusão de altas doses de ciclofosfamida, quadros retrospectivamente comprovados por elevação dos níveis sérico de peptídeo natriurético. O número reduzido de participantes não permitiu fazer análises estatísticas preditoras de cardiotoxicidade e foi uma limitação do estudo. Futuramente, objetivamos aumentar o número de pacientes do estudo e identificar marcadores preditivos de toxicidade cardíaca antes e durante o transplante / Autologous hematopoietic stem cell transplantation (AHSCT) is effective for the treatment of systemic sclerosis (SSc), with stabilization of pulmonary involvement and improvement of cutaneous fibrosis, quality of life and overall survival, when compared to non-transplanted patients. Transplant includes high dose cyclophosphamide, an immunosuppressive drug associated with potentially fatal cardiotoxicity. The evaluation of potential risk factors and clinical monitoring during the procedure may contribute to early identification of acute cardiac injury and thus improve the patient\'s clinical outcome. The aim of this study was to detect cardiac dysfunctions and to evaluate clinical and laboratory risk factors for the development of acute cardiac toxicity induced by cyclophosphamide in SSc patients submitted to AHSCT. This is a longitudinal and prospective study, conducted in the University Hospital of the Ribeirão Preto Medical School (Brazil), in patients with SSc, older than 18 years of age, from November 2016 to May 2018. The protocol has been approved by the Institutional Research Ethics Committee and all patients signed informed consent. Patients were evaluated for clinical and laboratory data, including natriuretic peptide dosage before, during and at the 6 months post-transplant time point Sixteen women with SSc were included, one of whom chose to discontinue participation in the study, having their data excluded. None of the participants had a history of psychoactive substance abuse or a diagnosis of diabetes mellitus. One patient was a passive smoker and another, an active smoker for 24 years, not smoking in the three months before transplantation. Two patients had their blood pressure controlled with antihypertensive drugs. During transplantation, 7 (46.7%) patients had cardiac changes associated with cyclophosphamide. The patients presented tachycardia, weight gain, increased central venous pressure and dyspnoea initiated in less than 24 hours and up to 4 days after the end of the infusion of the total cyclophosphamide dose (200mg / kg) of the transplant. In three of five patients investigated by echocardiography, alterations suggestive of cardiac dysfunction were detected, corroborating the clinical findings of cardiac dysfunction. One patient evolved with refractory shock and subsequent death due to multiple organ failure. One patient required pericardiocentesis due to cardiac tamponade and, in the others, management with medications reversed the clinical alterations. Serum natriuretic peptide levels were higher (p<0,0005) in the patients with than in the patients without any signs of cardiac toxicity. Clinical evaluations by the nursing staff allowed the detection of cardiac dysfunctions after infusion of high dose cyclophosphamide, retrospectively confirmed by elevation of serum levels of natriuretic peptide. The reduced number of participants did not allow for statistical analyzes to predict cardiotoxicity and was a limitation of the study. In the future, we aim to increase the number of patients in the study and to identify predictive markers of cardiotoxicity before and during transplant procedure

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 85-105).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 101-113).

The principal isoform of Src homology (SH) 2-domain containing 5' inositol phosphatase protein 1 (SHIP) is a 145kDa protein primarily expressed by cells of the hematopoietic compartment. The enzymatic activity of SHIP is responsible for hydrolyzing the 5' phosphate of phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3), and thereby preventing the recruitment of pleckstrin homology domain containing effector proteins. Furthermore, SHIP contains protein-protein interaction domains, such as an SH2 domain, two NPXY and several proline-rich motifs. All of these different domains endow SHIP with the capacity to impact signaling pathways important for proliferation, survival, differentiation and activation. Therefore, we hypothesized that SHIP-deficiency could result in the loss of hematopoietic cell homeostasis and functionTo this verify this hypothesis, we first studied the effect of SHIP ablation on hematopoietic stem cell (HSC) proliferation, survival, function and hom ing. Most interestingly we observed that SHIP impacts HSC homeostasis and their ability to home appropriately to the bone marrow. Then, since SHIP was shown to be activated after engagement of the c-mpl receptor by its ligand, thrombopoietin, we studied the impact of SHIP deletion on the function of megakaryocytes, the major target cell of that cytokine. We found that SHIP is also important for homeostasis of the megakaryocyte compartment. Thirdly, we studied the role of SHIP in natural killer (NK) cells biology. We observed that F4 generation SHIP-/- mice have increased NK cells in their spleen and that these cells exhibit a disrupted receptor repertoire. We verified the hypothesis that SHIP helps shape the receptor repertoire of NK cells, mainly through regulation of cell survival and proliferation. Also included, is a study on the role of a SHIP isoform lacking the SH2-domain, called stem cell-SHIP (s-SHIP) in the biology of embryonic stem (ES) cells. To date, this isoform i s expressed by stem/progenitor cells and not by normal differentiated cells. Due to its specific expression pattern, s-SHIP has the potential to have an important role in stem cell biology.

Hematopoietic stem and progenitor cells (HSPCs) repopulate the blood system upon transplantation. A large-scale genetic approach to understand the factors that participate in successful engraftment has not been undertaken. In this thesis, I present the development of a novel live imaging-based competitive marrow repopulation assay in adult zebrafish, which allows fast and quantitative measurement of HSPC engraftment capability. Using this assay, a transplantation-based chemical screen was performed, which led to the discovery of 10 compounds that can enhance the marrow engraftment capability in zebrafish. Among them, the arachidonic acid-derived epoxyeicosatrienoic acids (EET), had conserved effects on both short- and long-term bone marrow engraftment in mice. Genetic analysis in zebrafish embryos demonstrated that EET acts through a \(G\alpha12/13\)-mediated receptor, which activates PI3K and induces transcription factors of the AP-1 family. This PI3K/AP-1 pathway directly induced the transcription of HSC marker, runx1, in embryos. The activation of PI3K by EET promoted HSPC migration and interactions with niche cells. Our studies define a role for EETs in the development of blood stem cells during embryogenesis, and in engraftment in adult vertebrates. The other compounds discovered in the screen implicate additional novel signaling pathways involved in the HSPC engraftment process, which require further investigation. In summary, this thesis elucidated an important role of bioactive lipids in regulating HSC engraftment in adults and during embryo development. Systematically mapping out the regulatory network will tremendously benefit both the basic understanding of stem cell biology and the clinical manipulation to generate better stem cells for transplantation.