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1.
BMJ Lead ; 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38418198

RESUMO

BACKGROUND: The complexity of US healthcare has been increasing for many years, requiring clinicians and learners to understand care delivery systems in addition to clinical sciences. Thus, there has been a major push to educate faculty and trainees on healthcare functionality. This comes as hospitals expand into health systems requiring the help of more sophisticated expertise of departments such as operations excellence when problem-solving. As a medical student with a background in operations excellence, medical education leader and clinical administration leader all currently facilitating this transition, we wanted to reflect on the barriers we have experienced in clinical implementation of quality improvement projects and educating learners on the impact of operations excellence principles in their clinical education. METHODS: The ideas presented in this article were the result of a several collaborative discussion between the authors, on the key challenges to adopting operations excellence principles into health system science education. In an effort to add context to this reflection through the current body of research present, they supplemented a literature review on the topic which included 86 studies published between 2013 and 2021 regarding health systems science and healthcare leadership engagement in the USA. The themes that intersected between the literature review and the discussions were then expanded on in this paper. RESULTS: Through this process, we identified four challenges: (1) the difference in thinking styles, which we term, 'mental model differences'; (2) the strategic nature of process improvement projects and how that collides with physician priorities, or 'the chess game of stakeholder engagement'; (3) the language and precise methodology, or 'consistency of language and need for administrative resilience' and (4) the issue of teaching these concepts or bridging the learning gap.' CONCLUSION: In an increasingly complex healthcare landscape, physicians and trainee's need to bridge gaps between the mental models of administrative and clinical workflow.

2.
Sci Adv ; 9(30): eade3557, 2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37494432

RESUMO

Electroreduction of carbon dioxide (CO2) or carbon monoxide (CO) toward C2+ hydrocarbons such as ethylene, ethanol, acetate and propanol represents a promising approach toward carbon-negative electrosynthesis of chemicals. Fundamental understanding of the carbon─carbon (C-C) coupling mechanisms in these electrocatalytic processes is the key to the design and development of electrochemical systems at high energy and carbon conversion efficiencies. Here, we report the investigation of CO electreduction on single-atom copper (Cu) electrocatalysts. Atomically dispersed Cu is coordinated on a carbon nitride substrate to form high-density copper─nitrogen moieties. Chemisorption, electrocatalytic, and computational studies are combined to probe the catalytic mechanisms. Unlike the Langmuir-Hinshelwood mechanism known for copper metal surfaces, the confinement of CO adsorption on the single-copper-atom sites enables an Eley-Rideal type of C-C coupling between adsorbed (*CO) and gaseous [CO(g)] carbon moxide molecules. The isolated Cu sites also selectively stabilize the key reaction intermediates determining the bifurcation of reaction pathways toward different C2+ products.

4.
Arch Dermatol Res ; 314(1): 71-76, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33683446

RESUMO

Physician burnout and its association with the use of electronic health records (EHRs) is well known. The impact of scribes for academic dermatologists and their patients needs to be explored. As physician burnout increases, system-based solutions are needed. To assess the impact of a scribe on physician and patient satisfaction at an academic dermatology clinic. Prospective, pre-post-pilot intervention study. During the pilot intervention, clinicians had clinic sessions with and without a scribe. We assessed changes in (1) clinician satisfaction and burnout, (2) time spent on EHR, and (3) patient satisfaction. An electronic 7-item baseline survey, 23-item mid-study survey, and a 22-item end-of-study survey to assess clinician burnout and feedback on satisfaction with medical scribes. A 19-item post visit satisfaction survey was given to patients. EHR was queried to compare amount of time spent on EHR, closure of charts, and number of patients seen during scribe coverage and at baseline. Of the six clinicians, 100% felt that there was value to scribe support. Physician burnout was low at baseline and did not change post-pilot. Active documentation time, on average, decreased by 67% per patient with a 28% increase in patients seen per clinic. Over 88% of patients disagreed with the statement, "I was uncomfortable disclosing personal information when a scribe was present" (p < 0.001). In an academic dermatology and Mohs surgery setting, medical scribes increased clinician satisfaction without compromising patient satisfaction.


Assuntos
Atitude do Pessoal de Saúde , Dermatologia , Documentação/métodos , Registros Eletrônicos de Saúde , Satisfação no Emprego , Satisfação do Paciente , Médicos/psicologia , Eficiência Organizacional , Humanos , Projetos Piloto , Estudos Prospectivos , Inquéritos e Questionários , Fatores de Tempo
6.
Mol Ther Methods Clin Dev ; 17: 429-440, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32154328

RESUMO

Sickle cell disease (SCD) and ß-thalassemia are caused by structural abnormality or inadequate production of adult hemoglobin (HbA, α2ß2), respectively. Individuals with either disorder are asymptomatic before birth because fetal hemoglobin (HbF, α2γ2) is unaffected. Thus, reversal of the switch from HbF to HbA could reduce or even prevent symptoms these disorders. In this study, we show that insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is one factor that could accomplish this goal. IGF2BP1 is a fetal factor that undergoes a transcriptional switch consistent with the transition from HbF to HbA. Lentivirus delivery of IGF2BP1 to CD34+ cells of healthy adult donors reversed hemoglobin production toward the fetal type in culture-differentiated erythroid cells. Analogous studies using patient-derived CD34+ cells revealed that IGF2BP1-dependent HbF induction could ameliorate the chain imbalance in ß-thalassemia or potently suppress expression of sickle ß-globin in SCD. In all cases, fetal γ-globin mRNA increased and adult ß-globin decreased due, in part, to formation of contacts between the locus control region (LCR) and γ-globin genes. We conclude that expression of IGF2BP1 in adult erythroid cells has the potential to maximize HbF expression in patients with severe ß-hemoglobin disorders by reversing the developmental γ- to ß-globin switch.

7.
Nat Chem ; 12(3): 284-293, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32094437

RESUMO

Functionalizing the surfaces of transition metal dichalcogenide (TMD) nanosheets with noble metals is important for electrically contacting them to devices, as well as improving their catalytic and sensing capabilities. Solution-phase deposition provides a scalable approach to the creation of metal-TMD hybrid systems, but controlling such processes remains challenging. Here we elucidate the different pathways by which gold and silver deposit at room temperature onto colloidal 1T-WS2, 2H-WS2, 2H-MoSe2, 2H-WSe2, 1T'-MoTe2 and Td-WTe2 few-layer nanostructures to produce several distinct classes of 0D-2D and 2D-2D metal-TMD hybrids. Uniform gold nanoparticles form on all of the TMDs. By contrast, silver deposits as nanoparticles with a bimodal size distribution on the disulfides and diselenides, and as atomically thin layers on the ditellurides. The various sizes and morphologies of these surface-bound metal species arise from the relative strengths of the interfacial metal-chalcogen bonds during the reduction of Au3+ or Ag+ by the TMDs.

8.
J Am Chem Soc ; 141(42): 16635-16642, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31509393

RESUMO

Alloying is an important strategy for the design of catalytic materials beyond pure metals. The conventional alloy catalysts however lack precise control over the local atomic structures of active sites. Here we report on an investigation of the active-site ensemble effect in bimetallic Pd-Au electrocatalysts for CO2 reduction. A series of Pd@Au electrocatalysts are synthesized by decorating Au nanoparticles with Pd of controlled doses, giving rise to bimetallic surfaces containing Pd ensembles of various sizes. Their catalytic activity for electroreduction of CO2 to CO exhibits a nonlinear behavior in dependence of the Pd content, which is attributed to the variation of Pd ensemble size and the corresponding tuning of adsorption properties. Density functional theory calculations reveal that the Pd@Au electrocatalysts with atomically dispersed Pd sites possess lower energy barriers for activation of CO2 than pure Au and are also less poisoned by strongly binding *CO intermediates than pure Pd, with an intermediate ensemble size of active sites, such as Pd dimers, giving rise to the balance between these two rate-limiting factors and achieving the highest activity for CO2 reduction.

9.
J Autism Dev Disord ; 49(9): 3798-3806, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31172338

RESUMO

Children with autism often need sedation for diagnostic procedures and they are often difficult to sedate. This prospective randomized double-blind control trial evaluates the efficacy and safety using intranasal dexmedetomidine with and without buccal midazolam for sedation in children with autism undergoing computerized tomography and/or auditory brainstem response test. The primary outcome is the proportion of children attaining satisfactory sedation. One hundred and thirty-six children received intranasal dexmedetomidine and 139 received intranasal dexmedetomidine with buccal midazolam for sedation. Combination of intranasal dexmedetomidine and buccal midazolam was associated with higher sedation success when compared to intranasal dexmedetomidine. Since intranasal and buccal sedatives required little cooperation this could be especially useful technique for children with autism or other behavioral conditions.


Assuntos
Transtorno Autístico/tratamento farmacológico , Dexmedetomidina/administração & dosagem , Hipnóticos e Sedativos/administração & dosagem , Midazolam/administração & dosagem , Administração Bucal , Administração Intranasal , Criança , Pré-Escolar , Dexmedetomidina/efeitos adversos , Dexmedetomidina/uso terapêutico , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Hipnóticos e Sedativos/efeitos adversos , Hipnóticos e Sedativos/uso terapêutico , Masculino , Midazolam/efeitos adversos , Midazolam/uso terapêutico
10.
JCI Insight ; 4(3)2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30728332

RESUMO

Spine implant infections portend disastrous outcomes, as diagnosis is challenging and surgical eradication is at odds with mechanical spinal stability. Current imaging modalities can detect anatomical alterations and anomalies but cannot differentiate between infection and aseptic loosening, diagnose specific pathogens, or delineate the extent of an infection. Herein, a fully human monoclonal antibody 1D9, recognizing the immunodominant staphylococcal antigen A on the surface of Staphylococcus aureus, was assessed as a nuclear and fluorescent imaging probe in a preclinical model of S. aureus spinal implant infection, utilizing bioluminescently labeled bacteria to confirm the specificity and sensitivity of this targeting. Postoperative mice were administered 1D9 probe dual labeled with 89-zirconium (89Zr) and a near infrared dye (NIR680) (89Zr-NIR680-1D9), and PET-CT and in vivo fluorescence and bioluminescence imaging were performed. The 89Zr-NIR680-1D9 probe accurately diagnosed both acute and subacute implant infection and permitted fluorescent image-guided surgery for selective debridement of infected tissue. Therefore, a single probe could noninvasively diagnose an infection and facilitate image-guided surgery to improve the clinical management of implant infections.

11.
Transfusion ; 58(11): 2693-2704, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30312480

RESUMO

BACKGROUND: The 1000 Genomes Project provides a database of genomic variants from whole genome sequencing of 2504 individuals across five continental superpopulations. This database can enrich our background knowledge of worldwide blood group variant geographic distribution and identify novel variants of potential clinical significance. STUDY DESIGN AND METHODS: The 1000 Genomes database was analyzed to 1) expand knowledge about continental distributions of known blood group variants, 2) identify novel variants with antigenic potential and their geographic association, and 3) establish a baseline scaffold of chromosomal coordinates to translate next-generation sequencing output files into a predicted red blood cell (RBC) phenotype. RESULTS: Forty-two genes were investigated. A total of 604 known variants were mapped to the GRCh37 assembly; 120 of these were reported by 1000 Genomes in at least one superpopulation. All queried variants, including the ACKR1 promoter silencing mutation, are located within exon pull-down boundaries. The analysis yielded 41 novel population distributions for 34 known variants, as well as 12 novel blood group variants that warrant further validation and study. Four prediction algorithms collectively flagged 79 of 109 (72%) known antigenic or enzymatically detrimental blood group variants, while 4 of 12 variants that do not result in an altered RBC phenotype were flagged as deleterious. CONCLUSION: Next-generation sequencing has known potential for high-throughput and extended RBC phenotype prediction; a database of GRCh37 and GRCh38 chromosomal coordinates for 120 worldwide blood group variants is provided as a basis for this clinical application.


Assuntos
Genoma Humano/genética , Genômica/métodos , Algoritmos , Antígenos de Grupos Sanguíneos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos
12.
Am J Public Health ; 108(10): 1296-1302, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30138066

RESUMO

OBJECTIVES: To determine the lung cancer screening yield and stages in a union-sponsored low-dose computerized tomography scan program for nuclear weapons workers with diverse ages, smoking histories, and occupations. METHODS: We implemented a low-dose computerized tomography program among 7189 nuclear weapons workers in 9 nonmetropolitan US communities during 2000 to 2013. Eligibility criteria included age, smoking, occupation, radiographic asbestos-related fibrosis, and a positive beryllium lymphocyte proliferation test. RESULTS: The proportion with screen-detected lung cancer among smokers aged 50 years or older was 0.83% at baseline and 0.51% on annual scan. Of 80 lung cancers, 59% (n = 47) were stage I, and 10% (n = 8) were stage II. Screening yields of study subpopulations who met the National Lung Screening Trial or the National Comprehensive Cancer Network Group 2 eligibility criteria were similar to those found in the National Lung Screening Trial. CONCLUSIONS: Computerized tomography screening for lung cancer among high-risk workers leads to a favorable yield of early-stage lung cancers. Public Health Implications. Health equity and efficiency dictate that screening high-risk workers for lung cancer should be an important public health priority.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/etiologia , Programas de Rastreamento , Neoplasias Induzidas por Radiação/diagnóstico por imagem , Neoplasias Induzidas por Radiação/etiologia , Armas Nucleares , Doenças Profissionais/diagnóstico por imagem , Exposição Ocupacional/efeitos adversos , Exposição à Radiação , Tomografia Computadorizada por Raios X , Idoso , Feminino , Humanos , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Induzidas por Radiação/epidemiologia , Doenças Profissionais/epidemiologia , Doenças Profissionais/etiologia , Doenças Profissionais/patologia , Doses de Radiação , Fatores de Risco , Fumar/epidemiologia , Estados Unidos/epidemiologia
13.
Clin J Oncol Nurs ; 22(4): 464, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30035779

RESUMO

As a new nurse, I was aware of how judging or stereotyping someone based on religion, gender, culture, or other bias can inhibit a caring nurse-patient relationship. Expectations or preferences of my patients and their family members in certain caregiving scenarios influenced our interactions, and, as a male healthcare professional, I learned how cultural context, interactions with unrelated people of the opposite gender, modesty, and masculinity could become barriers if not addressed. My own experience, beginning as a nurse and progressing to a nurse practitioner, has offered opportunities for me to expand the horizons of myself and my patients.


Assuntos
Assistência à Saúde Culturalmente Competente , Profissionais de Enfermagem/psicologia , Relações Enfermeiro-Paciente , Enfermagem Oncológica , Preconceito/psicologia , Estereotipagem , Adulto , Atitude do Pessoal de Saúde , Humanos , Masculino
14.
J Transl Med ; 15(1): 169, 2017 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-28768505

RESUMO

BACKGROUND: In humans, the heterochronic cascade composed of the RNA-binding protein LIN28 and its major target, the let-7 family of microRNAs (miRNAs), is highly regulated during human erythroid ontogeny. Additionally, down-regulation of the let-7 miRNAs in cultured adult CD34(+) cells or the over-expression of LIN28 in cultured erythrocytes from pediatric patients with HbSS genotype causes increased levels of fetal hemoglobin (HbF) in the range of 19-40% of the total. Therefore, we hypothesized that focused targeting of individual let-7 miRNA family members would exhibit regulatory effect on HbF expression in human adult erythroblasts. METHODS: The expression levels of mature let-7 family members were measured by RT-qPCR in purified cell populations sorted from peripheral blood. To study the effects of let-7 miRNAs upon globin expression, a lentiviral construct that incorporated the tough decoy (TuD) design to target let-7a or let-7b was compared with empty vector controls. Transductions were performed in CD34(+) cells from adult healthy volunteers cultivated ex vivo in erythropoietin-supplemented serum-free media for 21 days. Downstream analyses included RT-qPCR, Western blot and HPLC for the characterization of adult and fetal hemoglobins. RESULTS: The expression of individual let-7 miRNA family members in adult peripheral blood cell populations demonstrated that let-7a and let-7b miRNAs are expressed at much higher levels than the other let-7 family members in purified adult human blood cell subsets with expression being predominantly in reticulocytes. Therefore, we focused this study upon the targeted inhibition of let-7a and let-7b with the TuD design to explore its effects upon developmentally-timed erythroid genes. Let-7a-TuD transductions significantly increased gamma-globin mRNA expression and HbF to an average of 38%. Let-7a-TuD also significantly decreased the mRNA expression of some ontogeny-regulated erythroid genes, namely CA1 and GCNT2. In addition, the erythroid-related transcription factors BCL11A and HMGA2 were down- and up-regulated, respectively, by let-7a-TuD, while ZBTB7A, KLF1 and SOX6 remained unchanged. CONCLUSIONS: Overall, our data demonstrate that let-7 miRNAs are differentially expressed in human hematopoietic cells, and that targeted inhibition of the highly-expressed species of this family is sufficient for developmentally-specific changes in gamma-globin expression and HbF levels.


Assuntos
Células-Tronco Hematopoéticas/metabolismo , MicroRNAs/metabolismo , Adulto , Sequência de Bases , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Diferenciação Celular , Proliferação de Células/genética , Células Cultivadas , Hemoglobina Fetal , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Proteína HMGA2/genética , Proteína HMGA2/metabolismo , Células-Tronco Hematopoéticas/citologia , Humanos , MicroRNAs/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Repressoras , Reticulócitos/metabolismo , gama-Globinas/genética , gama-Globinas/metabolismo
15.
Proc Natl Acad Sci U S A ; 114(28): E5664-E5672, 2017 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-28652347

RESUMO

Here we investigated in primary human erythroid tissues a downstream element of the heterochronic let-7 miRNA pathway, the insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), for its potential to affect the hemoglobin profiles in human erythroblasts. Comparison of adult bone marrow to fetal liver lysates demonstrated developmental silencing in IGF2BP1. Erythroid-specific overexpression of IGF2BP1 caused a nearly complete and pancellular reversal of the adult pattern of hemoglobin expression toward a more fetal-like phenotype. The reprogramming of hemoglobin expression was achieved at the transcriptional level by increased gamma-globin combined with decreased beta-globin transcripts resulting in gamma-globin rising to 90% of total beta-like mRNA. Delta-globin mRNA was reduced to barely detectable levels. Alpha-globin levels were not significantly changed. Fetal hemoglobin achieved levels of 68.6 ± 3.9% in the IGF2BP1 overexpression samples compared with 5.0 ± 1.8% in donor matched transduction controls. In part, these changes were mediated by reduced protein expression of the transcription factor BCL11A. mRNA stability and polysome studies suggest IGF2BP1 mediates posttranscriptional loss of BCL11A. These results suggest a mechanism for chronoregulation of fetal and adult hemoglobin expression in humans.


Assuntos
Proteínas de Transporte/metabolismo , Eritroblastos/metabolismo , Hemoglobina Fetal/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Proteínas Nucleares/metabolismo , Proteínas de Ligação a RNA/metabolismo , Medula Óssea/metabolismo , Células HEK293 , Proteína HMGA2/metabolismo , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Fígado/embriologia , Fenótipo , RNA Mensageiro/metabolismo , Proteínas Repressoras , Globinas beta/metabolismo , gama-Globinas/metabolismo
16.
Proc Natl Acad Sci U S A ; 114(5): E689-E696, 2017 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-28096387

RESUMO

Although it has been known for more than 60 years that the cause of sickle cell disease is polymerization of a hemoglobin mutant, hydroxyurea is the only drug approved for treatment by the US Food and Drug Administration. This drug, however, is only partially successful, and the discovery of additional drugs that inhibit fiber formation has been hampered by the lack of a sensitive and quantitative cellular assay. Here, we describe such a method in a 96-well plate format that is based on laser-induced polymerization in sickle trait cells and robust, automated image analysis to detect the precise time at which fibers distort ("sickle") the cells. With this kinetic method, we show that small increases in cell volume to reduce the hemoglobin concentration can result in therapeutic increases in the delay time prior to fiber formation. We also show that, of the two drugs (AES103 and GBT440) in clinical trials that inhibit polymerization by increasing oxygen affinity, one of them (GBT440) also inhibits sickling in the absence of oxygen by two additional mechanisms.


Assuntos
Antidrepanocíticos/farmacologia , Tamanho Celular/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Furaldeído/análogos & derivados , Anemia Falciforme/terapia , Eritrócitos/fisiologia , Furaldeído/farmacologia , Hemoglobina Falciforme/metabolismo , Humanos , Cinética , Oxigênio
17.
PLoS One ; 11(11): e0166928, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27861570

RESUMO

Induction of fetal hemoglobin (HbF) has therapeutic importance for patients with beta-hemoglobin disorders. Previous studies showed that let-7 microRNAs (miRNAs) are highly regulated in erythroid cells during the fetal-to-adult developmental transition, and that targeting let-7 mediated the up-regulation of HbF to greater than 30% of the total globin levels in human adult cultured erythroblasts. HMGA2 is a member of the high-mobility group A family of proteins and a validated target of the let-7 family of miRNAs. Here we investigate whether expression of HMGA2 directly regulates fetal hemoglobin in adult erythroblasts. Let-7 resistant HMGA2 expression was studied after lentiviral transduction of CD34(+) cells. The transgene was regulated by the erythroid-specific gene promoter region of the human SPTA1 gene (HMGA2-OE). HMGA2-OE caused significant increases in gamma-globin mRNA expression and HbF to around 16% of the total hemoglobin levels compared to matched control transductions. Interestingly, no significant changes in KLF1, SOX6, GATA1, ZBTB7A and BCL11A mRNA levels were observed. Overall, our data suggest that expression of HMGA2, a downstream target of let-7 miRNAs, causes moderately increased gamma-globin gene and protein expression in adult human erythroblasts.


Assuntos
Eritroblastos/metabolismo , Hemoglobina Fetal/genética , Regulação da Expressão Gênica , Proteína HMGA2/metabolismo , Adulto , Diferenciação Celular/genética , Células Cultivadas , Eritroblastos/citologia , Eritropoese/genética , Hemoglobina Fetal/metabolismo , Expressão Gênica , Proteína HMGA2/genética , Humanos , MicroRNAs/genética , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fatores de Transcrição/metabolismo , gama-Globinas/genética , gama-Globinas/metabolismo
18.
BMC Struct Biol ; 16(1): 13, 2016 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-27578274

RESUMO

BACKGROUND: Diversity-generating retroelements (DGRs) provide organisms with a unique means for adaptation to a dynamic environment through massive protein sequence variation. The potential scope of this variation exceeds that of the vertebrate adaptive immune system. DGRs were known to exist only in viruses and bacteria until their recent discovery in archaea belonging to the 'microbial dark matter', specifically in organisms closely related to Nanoarchaeota. However, Nanoarchaeota DGR variable proteins were unassignable to known protein folds and apparently unrelated to characterized DGR variable proteins. RESULTS: To address the issue of how Nanoarchaeota DGR variable proteins accommodate massive sequence variation, we determined the 2.52 Å resolution limit crystal structure of one such protein, AvpA, which revealed a C-type lectin (CLec)-fold that organizes a putative ligand-binding site that is capable of accommodating 10(13) sequences. This fold is surprisingly reminiscent of the CLec-folds of viral and bacterial DGR variable protein, but differs sufficiently to define a new CLec-fold subclass, which is consistent with early divergence between bacterial and archaeal DGRs. The structure also enabled identification of a group of AvpA-like proteins in multiple putative DGRs from uncultivated archaea. These variable proteins may aid Nanoarchaeota and these uncultivated archaea in symbiotic relationships. CONCLUSIONS: Our results have uncovered the widespread conservation of the CLec-fold in viruses, bacteria, and archaea for accommodating massive sequence variation. In addition, to our knowledge, this is the first report of an archaeal CLec-fold protein.


Assuntos
Archaea/genética , Proteínas Arqueais/química , Lectinas Tipo C/química , Retroelementos/genética , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Cristalografia por Raios X , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Simulação de Dinâmica Molecular , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação
19.
PLoS One ; 11(4): e0153244, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27116614

RESUMO

Sickle cell anemia (SCA) is an inherited hemolytic anemia with compensatory reticulocytosis. Recent studies have shown that increased levels of reticulocytosis during infancy are associated with increased hospitalizations for SCA sequelae as well as cerebrovascular pathologies. In this study, absolute reticulocyte counts (ARC) measured prior to transfusion were analysed among a cohort of 29 pediatric SCA patients receiving chronic transfusion therapy (CTT) for primary and secondary stroke prevention. A cross-sectional flow cytometric analysis of the reticulocyte phenotype was also performed. Mean duration of CTT was 3.1 ± 2.6 years. Fifteen subjects with magnetic resonance angiography (MRA) -vasculopathy had significantly higher mean ARC prior to initiating CTT compared to 14 subjects without MRA-vasculopathy (427.6 ± 109.0 K/µl vs. 324.8 ± 109.2 K/µl, p<0.05). No significant differences in hemoglobin or percentage sickle hemoglobin (HbS) were noted between the two groups at baseline. Reticulocyte phenotyping further demonstrated that the percentages of circulating immature [CD36(+), CD71(+)] reticulocytes positively correlated with ARC in both groups. During the first year of CTT, neither group had significant reductions in ARC. Among this group of children with SCA, cerebrovasculopathy on MRA at initiation of CTT was associated with increased reticulocytosis, which was not reduced after 12 months of transfusions.


Assuntos
Anemia Falciforme/sangue , Anemia Falciforme/terapia , Transfusão de Sangue , Reticulocitose , Adolescente , Anemia Falciforme/complicações , Transfusão de Sangue/métodos , Criança , Pré-Escolar , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Angiografia por Ressonância Magnética , Masculino , Contagem de Reticulócitos , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/prevenção & controle , Adulto Jovem
20.
Biol Blood Marrow Transplant ; 22(5): 825-33, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26806586

RESUMO

B cell antihost antibody production plays a central role in chronic graft-versus-host disease (cGVHD). T follicular helper (TFH) cells drive B cell responses and are implicated in this process. Given differences in cGVHD incidence between umbilical cord blood (UCB) and adult donor transplant recipients, we evaluated TFH cell reconstitution kinetics to define graft source differences and their potential pathogenic role in cGVHD. Although we observed significantly fewer TFH cells in the blood of UCB recipients (versus matched related donors [MRD]) early after transplantation, by 1 year the numbers of TFH cells were similar. Additionally, at both early (day 60) and late (1 year) time points, TFH cell phenotype was predominantly central memory cells in both cohorts. TFH cells were functional and able to produce multiple cytokines (INF-γ, TNF-α, IL-2, IL-17, and IL-21) after stimulation. In contrast to mouse models, where an enhanced frequency of splenic TFH cells contributes to cGVHD, patients with cGVHD showed significantly depleted circulating TFH cells after both UCB and MRD transplantation. Low numbers of TFH cells early after UCB transplantation could directly contribute to less cGVHD in this cohort. Additionally, systemic therapy (including steroids and calcineurin inhibitors) may contribute to decreases in TFH cells in patients with cGVHD. These data provide further evidence supporting the importance of TFH cells in cGVHD pathogenesis.


Assuntos
Citocinas/sangue , Citocinas/imunologia , Doença Enxerto-Hospedeiro/sangue , Doença Enxerto-Hospedeiro/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Adulto , Idoso , Animais , Doença Crônica , Feminino , Seguimentos , Doença Enxerto-Hospedeiro/patologia , Humanos , Contagem de Linfócitos , Masculino , Camundongos , Pessoa de Meia-Idade , Linfócitos T Auxiliares-Indutores/patologia
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