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Typical Kunitz proteins (I2 family of the MEROPS database, Kunitz-A family) are metazoan competitive inhibitors of serine peptidases that form tight complexes of 1:1 stoichiometry, mimicking substrates. The cestode Echinococcus granulosus, the dog tapeworm causing cystic echinococcosis in humans and livestock, encodes an expanded family of monodomain Kunitz proteins, some of which are secreted to the dog host interface. The Kunitz protein EgKU-7 contains, in addition to the Kunitz domain with the anti-peptidase loop comprising a critical arginine, a C-terminal extension of â¼20 amino acids. Kinetic, electrophoretic, and mass spectrometry studies using EgKU-7, a C-terminally truncated variant, and a mutant in which the critical arginine was substituted by alanine, show that EgKU-7 is a tight inhibitor of bovine and canine trypsins with the unusual property of possessing two instead of one site of interaction with the peptidases. One site resides in the anti-peptidase loop and is partially hydrolyzed by bovine but not canine trypsins, suggesting specificity for the target enzymes. The other site is located in the C-terminal extension. This extension can be hydrolyzed in a particular arginine by cationic bovine and canine trypsins but not by anionic canine trypsin. This is the first time to our knowledge that a monodomain Kunitz-A protein is reported to have two interaction sites with its target. Considering that putative orthologs of EgKU-7 are present in other cestodes, our finding unveils a novel piece in the repertoire of peptidase-inhibitor interactions and adds new notes to the evolutionary host-parasite concerto.
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Echinococcus granulosus , Proteínas de Helminto , Echinococcus granulosus/enzimologia , Echinococcus granulosus/genética , Echinococcus granulosus/metabolismo , Animais , Cães , Proteínas de Helminto/metabolismo , Proteínas de Helminto/genética , Proteínas de Helminto/química , Inibidores da Tripsina/metabolismo , Inibidores da Tripsina/química , Bovinos , Sequência de Aminoácidos , Tripsina/química , Tripsina/metabolismoRESUMO
BACKGROUND: Delirium is one of the most common adverse events in older people during hospitalization, especially in the emergency department. Reliable, easy-to-use instruments are necessary to properly manage delirium in this setting. This study aims to evaluate the diagnostic validity of the Spanish version of the 4 'A's Test (4AT) in the ED. METHODS: A diagnostic accuracy study was conducted in patients over 65 years old admitted to the Emergency Department who did not have a formal diagnosis of dementia or a severe mental health disorder. Face and content validity were evaluated by an expert panel. Emergency nurses performed the evaluation with 4AT, whilst blinded and trained researchers assessed patients with the Revised Delirium Rating Scale as the gold standard. The content validity index, sensitivity, specificity, positive and negative predictive values, likelihood ratios, Youden's Index and ROC curves were calculated to evaluate the diagnostic accuracy of the instrument. RESULTS: Of 393 eligible patients, 380 were finally analyzed. Content validity yielded a median content validity index of 4 (interquartile range: 0). The Spanish 4AT sensitivity (95.83%; 95% ECI: 78.9-99.9%), specificity (92.98%; 95% CI: 89.8-95.4%), positive predictive value (47.92%) and negative predictive value (99.7%) were satisfactory. Youden's index was 0.89. Positive likelihood ratio was 13.65, and negative likelihood ratio 0.045. The area under the curve was 0.97. CONCLUSIONS: The Spanish version of the 4AT for use in the Emergency Departments is easy-to-use and applicable. The validation results indicate that it is a valid instrument with sufficient predictive validity to identify patients at risk of delirium in the Emergency Departments. Moreover, it is a tool that facilitates the management of an adverse event that is associated with increased mortality and morbidity.
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Little is known about how low-income residents of urban communities engage their knowledge, attitudes, behaviors, and resources to mitigate the health impacts of wildfire smoke and other forms of air pollution. We interviewed 40 adults in Los Angeles, California, to explore their threat assessments of days of poor air quality, adaptation resources and behaviors, and the impacts of air pollution and wildfire smoke on physical and mental health. Participants resided in census tracts that were disproportionately burdened by air pollution and socioeconomic vulnerability. All participants reported experiencing days of poor air quality due primarily to wildfire smoke. Sixty percent received advanced warnings of days of poor air quality or routinely monitored air quality via cell phone apps or news broadcasts. Adaptation behaviors included remaining indoors, circulating indoor air, and wearing face masks when outdoors. Most (82.5%) of the participants reported some physical or mental health problem or symptom during days of poor air quality, but several indicated that symptom severity was mitigated by their adaptive behaviors. Although low-income residents perceive themselves to be at risk for the physical and mental health impacts of air pollution, they have also adapted to that risk with limited resources.
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Poluentes Atmosféricos , Poluição do Ar , Incêndios Florestais , Adulto , Humanos , Fumaça/efeitos adversos , Poluição do Ar/análise , Nicotiana , Pobreza , Poluentes Atmosféricos/análise , Material ParticuladoRESUMO
We are reporting our engagement with the 'Learning from Excellence' initiative in the neonatal intensive care unit during the covid era, with enhanced professional and personal stresses in the workforce. It highlights the positive experiences around technical management of sick neonates and human factors, like team working, leadership and communication.
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Since a great number of infant cardiopulmonary arrests occur outside of the hospital, it is crucial to train laypersons in cardiopulmonary resuscitation techniques, especially those professionals that will work with infants and children. The main objective of this study was to evaluate the efectiveness of ventilations performed by professional training students. The secondary objective was to analyze the preference between different ventilation and chest-compression methods. The sample consisted of 32 professional training students, 15 preschool students, and 17 physical education students. The activity was conducted separately for each group, and we provided a 10 min theoretical training about infant basic life support followed by a 45 min practical training using a Laerdal Little Anne QCPR CPR manikin. A practical test in pairs was organized to record the ventilation as performed by the participants, establishing the difference between the efficacious and the non-efficacious ones. Furthermore, we handed out a survey before and after training to evaluate their knowledge. More than 90% of the students completely agreed with the importance of learning cardiopulmonary resuscitation techniques for their professional future. More than half of the sample considered that they perform the rescue breathings with the mouth-to-mouth method better. We observed that through mouth-to-mouth-nose ventilations, the number of effective ventilations was significantly higher than the effective ventilations provided by a self-inflating bag and mask (EffectiveMtoMN 6.42 ± 4.27 vs. EffectiveMask 4.75 ± 3.63 (p = 0.007)), which was the preferred method. In terms of the compression method, hands encircling the chest was preferred by more than 85% of students. Mouth-to-mouth nose ventilation is more efficient than bag-face-mask ventilation in CPR as performed by professional training and physical activity students. This fact must be considered to provide higher-quality training sessions to professional training students.
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Reanimação Cardiopulmonar , Parada Cardíaca , Lactente , Pré-Escolar , Humanos , Criança , Reanimação Cardiopulmonar/educação , Respiração , Estudantes , AutoimagemRESUMO
Little is known of how low-income residents of urban heat islands engage their knowledge, attitudes, behaviors, and resources to mitigate the health impacts of heat waves. In this qualitative study, we conducted semi-structured interviews with 40 adults in two such neighborhoods in Los Angeles California to explore their adaptation resources and behaviors, the impacts of heat waves on physical and mental health, and threat assessments of future heat waves. Eighty percent of participants received advanced warning of heat waves from television news and social media. The most common resource was air conditioning (AC) units or fans. However, one-third of participants lacked AC, and many of those with AC engaged in limited use due primarily to the high cost of electricity. Adaptation behaviors include staying hydrated, remaining indoors or going to cooler locations, reducing energy usage, and consuming certain foods and drinks. Most of the participants reported some physical or mental health problem or symptom during heat waves, suggesting vulnerability to heat waves. Almost all participants asserted that heat waves were likely to increase in frequency and intensity with adverse health effects for vulnerable populations. Despite limited resources, low-income residents of urban heat islands utilize a wide range of behaviors to minimize the severity of health impacts, suggesting they are both vulnerable and resilient to heat waves.
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Aclimatação , Temperatura Alta , Adulto , Cidades , Mudança Climática , Humanos , Avaliação de Resultados em Cuidados de Saúde , PobrezaRESUMO
Congenital anomalies (CA) affect 3-5% of newborns, representing the second-leading cause of infant mortality in Argentina. Multiple congenital anomalies (MCA) have a prevalence of 2.26/1000 births in newborns, while congenital heart diseases (CHD) are the most frequent CA with a prevalence of 4.06/1000 births. The aim of this study was to identify the genetic causes in Argentinian patients with MCA and isolated CHD. We recruited 366 patients (172 with MCA and 194 with isolated CHD) born between June 2015 and August 2019 at public hospitals. DNA from peripheral blood was obtained from all patients, while karyotyping was performed in patients with MCA. Samples from patients presenting conotruncal CHD or DiGeorge phenotype (n = 137) were studied using MLPA. Ninety-three samples were studied by array-CGH and 18 by targeted or exome next-generation sequencing (NGS). A total of 240 patients were successfully studied using at least one technique. Cytogenetic abnormalities were observed in 13 patients, while 18 had clinically relevant imbalances detected by array-CGH. After MLPA, 26 patients presented 22q11 deletions or duplications and one presented a TBX1 gene deletion. Following NGS analysis, 12 patients presented pathogenic or likely pathogenic genetic variants, five of them, found in KAT6B, SHH, MYH11, MYH7 and EP300 genes, are novel. Using an algorithm that combines molecular techniques with clinical and genetic assessment, we determined the genetic contribution in 27.5% of the analyzed patients.
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Anormalidades Múltiplas , Cardiopatias Congênitas , Anormalidades Múltiplas/genética , Algoritmos , Testes Genéticos , Cardiopatias Congênitas/genética , Histona Acetiltransferases , Humanos , CariotipagemRESUMO
Resumen: Introducción: la cirugía micrográfica de Mohs es una técnica quirúrgica especializada para el tratamiento del cáncer de piel no melanoma. La histopatología cumple un rol fundamental, y la elección de la tinción es un punto de controversia. Objetivos: comparar el rendimiento de las tinciones de hematoxilina y eosina (HyE) versus azul de toluidina (AT) durante la cirugía. Método: estudio observacional, descriptivo y transversal a partir de noviembre de 2017 hasta mayo de 2018. Se incluyeron las láminas empleadas durante la cirugía en el período mencionado. Estas fueron analizadas por el cirujano de Mohs, tres residentes y una dermopatóloga. Se valoró el rendimiento de ambas tinciones, teniendo en cuenta las características celulares y los elementos del estroma. Resultados: se estudiaron 23 tumores (16 carcinomas basocelulares y 7 carcinomas espinocelulares). Al observarse al microscopio óptico tanto con la tinción de AT como con HyE no se encontraron diferencias significativas entre ambos grupos en lo global, sólo en algunas características, especialmente con la HyE. Conclusiones: es el primer trabajo en Uruguay que compara la eficacia de las dos tinciones durante la cirugía micrográfica de Mohs. Como conclusión tanto la tinción de HyE como el AT son muy buenas técnicas para el diagnóstico de carcinomas cutáneos.
Abstract: Introduction: Mohs micrographic surgery is a specialized surgical technique used to treat nonmelanoma carcinoma. Histopathology plays a vital role in the diagnosis of this condition, and the choice staining method is controversial. Objective: to compare results in the use of hematoxylin and eosin (H&E) versus Toluidine blue (TB) staining during surgery. Method: observational, descriptive and transversal study conducted from November, 2017 until May, 2018 of the slides used during surgeries in the selected period. Slides were analysed by the Mohs surgeon, 3 residents and a dermopathologist to evaluate the results of both staining methods, in consideration of cell features and stromal elements. Results: 23 tumors were analysed (16 Basal Cell carcinomas and 7 Squamous Cell Carcinoma). Microscopic observation of slides prepared with Toluidine blue and hematoxylin and eosin stains did not show significant global differences between both groups, except in terms of a few characteristics, in particular with hematoxylin and eosin stains. Conclusions: this was the first study in Uruguay to evaluate the effectiveness of both staining methods during Mohs micrographic surgery, and it concluded that both Toluidine blue and hematoxylin and eosin stains are very good techniques in evaluating skin-cancer.
Resumo: Introdução: a cirurgia micrográfica de Mohs é uma técnica cirúrgica especializada para o tratamento do câncer de pele não melanoma. A histopatologia desempenha um papel fundamental, onde a escolha da coloração é um ponto de controvérsia. Objetivos: comparar o desempenho das colorações de hematoxilina e eosina versus azul de toluidina durante a cirurgia. Método: estudo observacional, descritivo e transversal de novembro de 2017 a maio de 2018. Foram incluídas as lâminas utilizadas durante as cirurgias no referido período. Estas foram analisadas pelo cirurgião especializado na técnica de Mohs, 3 residentes e um dermatopatologista onde foi avaliado o desempenho de ambas as colorações, levando em consideração as características celulares e os elementos do estroma. Resultados: foram estudados 23 tumores (16 carcinomas basocelulares e 7 carcinomas espinocelulares). Quando observados ao microscópio de luz para coloração AT e H&E, não foram encontradas diferenças significativas entre os dois grupos em geral, apenas em algumas características, especialmente com o H&E. Conclusões: é o primeiro estudo no Uruguai que compara a eficácia dos 2 corantes durante a cirurgia micrográfica de Mohs. Em conclusão, tanto a coloração com hematoxilina e eosina quanto com azul de toluidina são técnicas muito boas para o diagnóstico de carcinomas de pele.
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Cirurgia de MohsRESUMO
In this study, sodium alginate (SA)-based, eco-friendly nanocomposites films were synthesized for potential food packaging applications using silver nitrate (AgNO3) as the metal precursor, reactive nitrogen and oxygen species (RNOS) created within plasma activated water (PAW), or through cold plasma treatment (CP) as reducing agent and SA as stabilizing agent. The formation of silver nanoparticles (AgNPs) was confirmed via the absorption peaks observed between 440 and 450 nm in UV-vis spectroscopy. The tensile strength (TS) and tensile modulus (TM) of the nanocomposite films were significantly higher than those of the SA films. An increase in the TS was also observed as the AgNP concentration was increased from 1 to 5 mM. The storage modulus (G') of the nanocomposite solution was higher than that of the SA solution. The synthesis of AgNPs resulted both in a higher solution viscosity and a more marked shear-thinning effect. The synthesized AgNPs showed antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The AgNPs were spherical in shape with an average size of 22 nm.
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Though AsCas12a fills a crucial gap in the current genome editing toolbox, it exhibits relatively poor editing efficiency, restricting its overall utility. Here we isolate an engineered variant, "AsCas12a Ultra", that increased editing efficiency to nearly 100% at all sites examined in HSPCs, iPSCs, T cells, and NK cells. We show that AsCas12a Ultra maintains high on-target specificity thereby mitigating the risk for off-target editing and making it ideal for complex therapeutic genome editing applications. We achieved simultaneous targeting of three clinically relevant genes in T cells at >90% efficiency and demonstrated transgene knock-in efficiencies of up to 60%. We demonstrate site-specific knock-in of a CAR in NK cells, which afforded enhanced anti-tumor NK cell recognition, potentially enabling the next generation of allogeneic cell-based therapies in oncology. AsCas12a Ultra is an advanced CRISPR nuclease with significant advantages in basic research and in the production of gene edited cell medicines.
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Acidaminococcus/enzimologia , Proteínas de Bactérias/metabolismo , Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas , Endonucleases/metabolismo , Edição de Genes/métodos , Acidaminococcus/genética , Proteínas de Bactérias/genética , Proteínas Associadas a CRISPR/genética , Células Cultivadas , Endonucleases/genética , Células HEK293 , Células-Tronco Hematopoéticas/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células Jurkat , Células Matadoras Naturais/metabolismo , Reprodutibilidade dos Testes , Linfócitos T/metabolismoRESUMO
The role of circumcision in partially protecting against sexually transmitted infections (STIs) and other dermatoses has been documented. Neonatal circumcision is not routinely practiced in South America. Although it is logical to assume that male genital dermatoses are more prevalent in Hispanic men, they are underrepresented in the existing literature. Objective: To describe the epidemiological characteristics from our male genital dermatology unit in Montevideo (Uruguay), the diagnoses, and correlate them with circumcision status and comorbidities. Methods: A retrospective observational cohort study was conducted. A dermatologist and urologist evaluated all patients using standard questionnaires. In 3 years and 8 months, 269 patients were seen. Median age was 41, prevalence of neonatal circumcision was 0.7%, HIV was 4.2%, STIs were 24.9%, non-STIs were 63.9%, and both (STI + non-STI) were 11.2%. Most frequent entities: eczema/balanoposthitis (27.1%), condyloma (24.9%), and lichen sclerosus (15.6%). Data correlating circumcision and other diagnoses did not reach statistical significance. HIV was positively associated with other STIs (p < 0.05), and an association with balanoposthitis was seen; however, it did not reach statistical significance (p < 0.1). Main limitation was small sample size. This is the first study of its kind based on Hispanic patients. Collaboration between specialties proved to be fundamental. Further studies are needed in this demographic to find an association between circumcision, comorbidities, and genital dermatoses.
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Circuncisão Masculina , Dermatologia , Adulto , Genitália , Hispânico ou Latino , Humanos , Recém-Nascido , Masculino , Estudos RetrospectivosRESUMO
Background: Oculocutaneous albinism (OCA) is a Mendelian disorder characterized by hypopigmentation of the skin, hair, and eyes, hypoplastic fovea, and low vision, known to be caused by mutations in the Tyrosinase (TYR) gene. Among the known TYR variants, some reduce but do not completely eliminate tyrosinase activity, allowing residual production of melanin and resulting in a contradictory assignment as either pathogenic or benign, preventing a precise clinical diagnostic.Materials and Methods: In the present work, we performed Whole Exome Sequencing and subsequent Sanger sequencing in a young male clinically diagnosed with OCA.Results: Whole-exome sequencing analysis revealed the identification of two variants in trans in TYR. The first, corresponds to a known pathogenic variant G47D, while the second S192Y, was considered a polymorphism due to its relatively high frequency in the European population.Conclusion: The lack of other pathogenic variants in TYR, the reported reduced enzymatic activity (ca. 40% respect to wt) for S192Y, together with the structural in-silico analysis strongly suggest that both reported variants are jointly disease-causing and that S192Y should be considered as likely pathogenic, especially when it is found in trans with a null variant.
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Albinismo Oculocutâneo/genética , Monofenol Mono-Oxigenase/genética , Mutação de Sentido Incorreto/genética , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Albinismo Oculocutâneo/diagnóstico , Sequência de Aminoácidos , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Sequenciamento do ExomaRESUMO
The genus Echinococcus of cestode parasites includes important pathogens of humans and livestock animals. Transcriptomic and genomic studies on E. granulosus and E. multilocularis uncovered striking expansion of monodomain Kunitz proteins. This expansion is accompanied by the specialization of some family members away from the ancestral protease inhibition function to fulfill cation channel blockade functions. Since cation channels are involved in immune processes, we tested the effects on macrophage physiology of two E. granulosus Kunitz-type inhibitors of voltage-activated cation channels (Kv) that are close paralogs. Both inhibitors, EgKU-1 and EgKU-4, inhibited production of the Th1/Th17 cytokine subunit IL-12/23p40 by macrophages stimulated with the TLR4 agonist LPS. In addition, EgKU-4 but not EgKU-1 inhibited production of the inflammatory cytokine IL-6. These activities were not displayed by EgKU-3, a family member that is a protease inhibitor without known activity on cation channels. EgKU-4 potently inhibited macrophage proliferation in response to M-CSF, whereas EgKU-1 displayed similar activity but with much lower potency, similar to EgKU-3. We discuss structural differences, including a heavily cationic C-terminal extension present in EgKU-4 but not in EgKU-1, that may explain the differential activities of the two close paralogs.
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Echinococcus granulosus/química , Proteínas de Helminto/farmacologia , Interleucina-12/antagonistas & inibidores , Interleucina-6/antagonistas & inibidores , Macrófagos/efeitos dos fármacos , Proteínas Secretadas Inibidoras de Proteinases/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Regulação da Expressão Gênica , Proteínas de Helminto/isolamento & purificação , Interleucina-10/genética , Interleucina-10/imunologia , Interleucina-12/genética , Interleucina-12/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Canal de Potássio Kv1.3/genética , Canal de Potássio Kv1.3/imunologia , Lipopolissacarídeos/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/citologia , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Cultura Primária de Células , Proteínas Secretadas Inibidoras de Proteinases/isolamento & purificação , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologiaRESUMO
OBJECTIVES: Current validated instruments to screen for pelvic organ prolapse and its sequelae address bulge symptoms, bowel and bladder changes, and sexual intimacy. However, sensitivity is lower in younger women, and there is no instrument specifically designed to screen in postpartum, primiparous women for early changes, that is, changes that may be noticed before the symptom of a bulge or signs of pelvic organ prolapse occur. Our goal was to elucidate early sensations of pelvic floor support changes in primiparous women after their first vaginal delivery. These could be the focus of future studies differentiating such sensations from a normal postpartum, aiding identification of women for further follow-up. METHODS: Using comparative focused ethnographic methods, we purposefully sampled and interviewed 17 multiparous women diagnosed with pelvic organ prolapse and 60 primiparous women, half Euro-American and half Mexican American, English or Spanish speaking. Audiotapes were transcribed and then translated. Using inductive coding and matrix analysis, we used constant comparison across transcript data and clustered coded data into body systems-level matrices to arrive at categories of early changes. RESULTS: We identified early changes by ethnic group in pelvic area sensations and bowel, bladder, and sexual function, including sensations not mentioned in extant questionnaires. CONCLUSIONS: Early changes may be distressing but difficult for women to introduce in a clinical conversation. Querying these changes may enhance patient-provider communication. Future research is needed to validate these items in questionnaires designed to identify women with persistent early changes that may lead to subsequent objective pelvic organ prolapse.
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Parto Obstétrico , Diafragma da Pelve/fisiologia , Sensação , Adulto , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Prolapso de Órgão Pélvico/diagnóstico , Período Pós-Parto , Transtornos Puerperais/diagnóstico , Pesquisa QualitativaRESUMO
The choice of alternative donors for HCT for patients without an HLA-matched related donor depends on several factors. We compared major HCT outcomes in 212 consecutive children transplanted at 11 centers in Brazil for acute leukemia or MDS from an HLA-matched unrelated donor (MUD, n = 95), mismatched unrelated donor (MMUD, n = 47) or unrelated umbilical cord blood (UCB, n = 70). Most had ALL (61%), bone marrow (57%) as the graft source and 95% received a MAC regimen. The 3-year OS probability were 57, 55, and 37% after HCT from MUD, MMUD, and UCB, respectively (HR 1.68, 95%CI 1.07-2.63; P = .02). In comparison with MUD, OS was similar after transplantation of a ≥ 6/8 HLA-matched or a high cell dose (>5 × 107 TNC/kg) CB unit (HR 1.41, 95%CI 0.88-2.27; P = .15). NRM was higher for UCB (HR 3.90, 95%CI 1.43-10.7; P = .01) but not for MMUD (HR 1.03, 95%CI 0.53-2.00; P > .20). Advanced disease (HR 2.05, 95%CI 1.26-3.33; P < .001) and UCB with high probability of being < 6/8 HLA-matched (HR 5.34, 95%CI 2.0-13.9; P < .001) were associated with higher mortality. Relapse and acute GVHD were similar among groups, while PGF was higher among UCB transplants (P = .002) and chronic GVHD among MMUD group (HR 2.88, 95% CI 1.05-7.88; P = .04). Our results suggest that in Brazil HCT outcomes performed with MMUD and MUD donors were comparable, while with UCB units < 6/8 HLA-matched were associated with higher NRM for children with acute leukemia or MDS.
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Transplante de Células-Tronco de Sangue do Cordão Umbilical/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Leucemia Mieloide Aguda/terapia , Síndromes Mielodisplásicas/terapia , Brasil/epidemiologia , Criança , Feminino , Sobrevivência de Enxerto , Humanos , Incidência , Leucemia Mieloide Aguda/epidemiologia , Masculino , Síndromes Mielodisplásicas/epidemiologia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Multiplexed genome editing with DNA endonucleases has broad application, including for cellular therapies, but chromosomal translocations, natural byproducts of inducing simultaneous genomic breaks, have not been explored in detail. Here we apply various CRISPR-Cas nucleases to edit the T cell receptor alpha and beta 2 microglobulin genes in human primary T cells and comprehensively evaluate the frequency and stability of the resulting translocations. A thorough translocation frequency analysis using three orthogonal methods (droplet digital PCR, unidirectional sequencing, and metaphase fluorescence in situ hybridization) yielded comparable results and an overall translocation rate of â¼7% between two simultaneous CRISPR-Cas9 induced edits. In addition, we show that chromosomal translocations can be reduced when using different nuclease combinations, or by the presence of a homologous single stranded oligo donor for multiplexed genome editing. Importantly, the two different approaches for translocation reduction are compatible with cell therapy applications.
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Sistemas CRISPR-Cas , Edição de Genes/métodos , Linfócitos T , Translocação Genética , Linfócitos T CD4-Positivos , Proteína 9 Associada à CRISPR/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , DNA/genética , Endonucleases/genética , Genoma Humano , Humanos , Hibridização in Situ Fluorescente , Herança Multifatorial , RNA Guia de Cinetoplastídeos , Streptococcus pyogenesRESUMO
RNA-guided endonucleases such as Cas9 provide efficient on-target genome editing in cells but may also cleave at off-target loci throughout the genome. Engineered variants of Streptococcus pyogenes Cas9 (SpCas9) have been developed to globally reduce off-target activity, but individual off-targets may remain, or on-target activity may be compromised. In order to evolve against activity at specific off-targets while maintaining strong on-target editing, we developed a novel M13 bacteriophage-mediated selection method. Using this method, sequential rounds of positive and negative selection are used to identify mutations to Cas9 that enhance or diminish editing activity at particular genomic sequences. We also introduce scanning mutagenesis of oligo-directed targets (SMOOT), a comprehensive mutagenesis method to create highly diverse libraries of Cas9 variants that can be challenged with phage-based selection. Our platform identifies novel SpCas9 mutants which mitigate cleavage against off-targets both in biochemical assays and in T-cells while maintaining higher on-target activity than previously described variants. We describe an evolved variant, S. pyogenes Adapted to Reduce Target Ambiguity Cas9 (SpartaCas), composed of the most enriched mutations, each of unknown function. This evolved Cas9 mutant reduces off-target cleavage while preserving efficient editing at multiple therapeutically relevant targets. Directed evolution of Cas9 using our system demonstrates an improved structure-independent methodology to effectively engineer nuclease activity.