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1.
N Engl J Med ; 390(18): 1663-1676, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38657265

RESUMO

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a nonviral cell therapy designed to reactivate fetal hemoglobin synthesis through ex vivo clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of the erythroid-specific enhancer region of BCL11A in autologous CD34+ hematopoietic stem and progenitor cells (HSPCs). METHODS: We conducted an open-label, single-group, phase 3 study of exa-cel in patients 12 to 35 years of age with transfusion-dependent ß-thalassemia and a ß0/ß0, ß0/ß0-like, or non-ß0/ß0-like genotype. CD34+ HSPCs were edited by means of CRISPR-Cas9 with a guide mRNA. Before the exa-cel infusion, patients underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end point was transfusion independence, defined as a weighted average hemoglobin level of 9 g per deciliter or higher without red-cell transfusion for at least 12 consecutive months. Total and fetal hemoglobin concentrations and safety were also assessed. RESULTS: A total of 52 patients with transfusion-dependent ß-thalassemia received exa-cel and were included in this prespecified interim analysis; the median follow-up was 20.4 months (range, 2.1 to 48.1). Neutrophils and platelets engrafted in each patient. Among the 35 patients with sufficient follow-up data for evaluation, transfusion independence occurred in 32 (91%; 95% confidence interval, 77 to 98; P<0.001 against the null hypothesis of a 50% response). During transfusion independence, the mean total hemoglobin level was 13.1 g per deciliter and the mean fetal hemoglobin level was 11.9 g per deciliter, and fetal hemoglobin had a pancellular distribution (≥94% of red cells). The safety profile of exa-cel was generally consistent with that of myeloablative busulfan conditioning and autologous HSPC transplantation. No deaths or cancers occurred. CONCLUSIONS: Treatment with exa-cel, preceded by myeloablation, resulted in transfusion independence in 91% of patients with transfusion-dependent ß-thalassemia. (Supported by Vertex Pharmaceuticals and CRISPR Therapeutics; CLIMB THAL-111 ClinicalTrials.gov number, NCT03655678.).


Assuntos
Hemoglobina Fetal , Edição de Genes , Transplante de Células-Tronco Hematopoéticas , Talassemia beta , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Adulto Jovem , Antígenos CD34 , Talassemia beta/terapia , Talassemia beta/genética , Transfusão de Sangue , Bussulfano/uso terapêutico , Sistemas CRISPR-Cas , Hemoglobina Fetal/biossíntese , Hemoglobina Fetal/genética , Edição de Genes/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas , Proteínas Repressoras/genética , Condicionamento Pré-Transplante , Transplante Autólogo , Agonistas Mieloablativos/uso terapêutico , América do Norte , Europa (Continente)
2.
Immunol Rev ; 308(1): 123-148, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35373371

RESUMO

Pregnant women infected with pathogenic respiratory viruses, such as influenza A viruses (IAV) and coronaviruses, are at higher risk for mortality, hospitalization, preterm birth, and stillbirth. Several factors are likely to contribute to the susceptibility of pregnant individuals to severe lung disease including changes in pulmonary physiology, immune defenses, and effector functions of some immune cells. Pregnancy is also a physiologic state characterized by higher levels of multiple hormones that may impact the effector functions of immune cells, such as progesterone, estrogen, human chorionic gonadotropin, prolactin, and relaxin. Each of these hormones acts to support a tolerogenic immune state of pregnancy, which helps prevent fetal rejection, but may also contribute to an impaired antiviral response. In this review, we address the unique role of adaptive and innate immune cells in the control of pathogenic respiratory viruses and how pregnancy and specific hormones can impact their effector actions. We highlight viruses with sex-specific differences in infection outcomes and why pregnancy hormones may contribute to fetal protection but aid the virus at the expense of the mother's health.


Assuntos
Infecções por Coronavirus , Vírus da Influenza A , Nascimento Prematuro , Feminino , Hormônios , Humanos , Recém-Nascido , Pulmão , Masculino , Gravidez
3.
N Engl J Med ; 384(3): 252-260, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33283989

RESUMO

Transfusion-dependent ß-thalassemia (TDT) and sickle cell disease (SCD) are severe monogenic diseases with severe and potentially life-threatening manifestations. BCL11A is a transcription factor that represses γ-globin expression and fetal hemoglobin in erythroid cells. We performed electroporation of CD34+ hematopoietic stem and progenitor cells obtained from healthy donors, with CRISPR-Cas9 targeting the BCL11A erythroid-specific enhancer. Approximately 80% of the alleles at this locus were modified, with no evidence of off-target editing. After undergoing myeloablation, two patients - one with TDT and the other with SCD - received autologous CD34+ cells edited with CRISPR-Cas9 targeting the same BCL11A enhancer. More than a year later, both patients had high levels of allelic editing in bone marrow and blood, increases in fetal hemoglobin that were distributed pancellularly, transfusion independence, and (in the patient with SCD) elimination of vaso-occlusive episodes. (Funded by CRISPR Therapeutics and Vertex Pharmaceuticals; ClinicalTrials.gov numbers, NCT03655678 for CLIMB THAL-111 and NCT03745287 for CLIMB SCD-121.).


Assuntos
Anemia Falciforme/terapia , Sistemas CRISPR-Cas , Hemoglobina Fetal/biossíntese , Edição de Genes/métodos , Terapia Genética , Proteínas Repressoras/genética , Talassemia beta/terapia , Adulto , Anemia Falciforme/genética , Feminino , Hemoglobina Fetal/genética , Humanos , Proteínas Repressoras/metabolismo , Adulto Jovem , Talassemia beta/genética
4.
J Am Chem Soc ; 145(29): 15827-15837, 2023 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-37438911

RESUMO

Photosynthetic organisms utilize dynamic and complex networks of pigments bound within light-harvesting complexes to transfer solar energy from antenna complexes to reaction centers. Understanding the principles underlying the efficiency of these energy transfer processes, and how they may be incorporated into artificial light-harvesting systems, is facilitated by the construction of easily tunable model systems. We describe a protein-based model to mimic directional energy transfer between light-harvesting complexes using a circular permutant of the tobacco mosaic virus coat protein (cpTMV), which self-assembles into a 34-monomer hollow disk. Two populations of cpTMV assemblies, one labeled with donor chromophores and another labeled with acceptor chromophores, were coupled using a direct protein-protein bioconjugation method. Using potassium ferricyanide as an oxidant, assemblies containing o-aminotyrosine were activated toward the addition of assemblies containing p-aminophenylalanine. Both of these noncanonical amino acids were introduced into the cpTMV monomers through amber codon suppression. This coupling strategy has the advantages of directly, irreversibly, and site-selectively coupling donor with acceptor protein assemblies and avoids cross-reactivity with native amino acids and undesired donor-donor or acceptor-acceptor combinations. The coupled donor-acceptor model was shown to transfer energy from an antenna disk containing donor chromophores to a downstream disk containing acceptor chromophores. This model ultimately provides a controllable and modifiable platform for understanding photosynthetic interassembly energy transfer and may lead to the design of more efficient functional light-harvesting materials.


Assuntos
Modelos Biológicos , Fotossíntese , Transferência de Energia , Complexos de Proteínas Captadores de Luz/química , Aminoácidos
5.
Artigo em Inglês | MEDLINE | ID: mdl-37582863

RESUMO

BACKGROUND: Self-stigma among people with mental illness is negatively associated with personal and clinical recovery. Due to the concealable nature of mental illness, people with mental illness experience constant struggles between concealment and disclosure. Disclosure of mental health challenges can potentially minimize negative impacts of self-stigma and enhance self-esteem and sense of empowerment. Honest, Open, Proud (HOP) is a peer-led intervention that promotes autonomous and dignified decisions about disclosure. PURPOSE: This study examined the effectiveness of HOP on concealment motivation, empowerment, self-stigma, stigma stress, and recovery among people with lived experience of mental illness in Hong Kong. METHODOLOGY: A total of 162 participants with a mean age of 45.38 were recruited and randomized into intervention group and waitlist control group. Participants in the intervention group were invited to attend a 6-session HOP group intervention. RESULTS: Significant improvement in optimism score from the empowerment scale was found in the intervention group compared to the waitlist control group and the effect was sustained at 1-month follow-up. However, significant changes were not found in other outcome variables. CONCLUSION: Only improvement in optimism was observed in the current study. Future study needs to examine the effects of HOP with further modification to maximize the benefit for people with lived experience of mental illness in the local context.

6.
Ann Clin Microbiol Antimicrob ; 21(1): 43, 2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36229877

RESUMO

Group B streptococci (GBS) are bacteria that can cause preterm birth and invasive neonatal disease. Heterogeneous expression of virulence factors enables GBS to exist as both commensal bacteria and to become highly invasive. A molecular epidemiological study comparing GBS bacterial traits, genotype and host characteristics may indicate whether it is possible to predict the risk of perinatal invasive GBS disease and more accurately target intrapartum antibiotic prophylaxis. A total of 229 invasive GBS isolates from Swedish pregnant women or neonates were assessed for virulence and phenotypic traits: hemolysis zone, hemolytic pigment (Granada agar), Streptococcus B Carrot Broth (SBCB) assay, CAMP factor, and hyaluronidase activity. Genes regulating hemolytic pigment synthesis (covR/covS, abx1, stk1, stp1) were sequenced. Of the virulence factors and phenotypes assessed, a Granada pigment or SBCB score ≥ 2 captured more than 90% of EOD isolates with excellent inter-rater reliability. High enzyme activity of hyaluronidase was observed in 16% (36/229) of the invasive GBS isolates and notably, in one case of stillbirth. Hyaluronidase activity was also significantly higher in GBS isolates obtained from pregnant/postpartum individuals versus the stillbirth or neonatal invasive isolates (p < 0.001). Sequencing analysis found that abx1 (g.T106I), stk1 (g.T211N), stp1 (g.K469R) and covS (g.V343M) variants were present significantly more often in the higher (Granada pigment score ≥ 2) versus lower pigmented isolates (p < 0.001, each variant). Among the 203 higher Granada pigment scoring isolates, 22 (10.8%) isolates had 3 of the four sequence variants and 10 (4.9%) had 2 of the four sequence variants. Although heterogeneity in GBS virulence factor expression was observed, the vast majority were more highly pigmented and contained several common sequence variants in genes regulating pigment synthesis. High activity of hyaluronidase may increase risk for stillbirth and invasive disease in pregnant or postpartum individuals. Our findings suggest that testing for GBS pigmentation and hyaluronidase may, albeit imperfectly, identify pregnant people at risk for invasive disease and represent a step towards a personalized medical approach for the administration of intrapartum antibiotic prophylaxis.


Assuntos
Nascimento Prematuro , Infecções Estreptocócicas , Ágar/metabolismo , Ágar/uso terapêutico , Antibacterianos/uso terapêutico , Feminino , Genótipo , Humanos , Hialuronoglucosaminidase/genética , Hialuronoglucosaminidase/metabolismo , Hialuronoglucosaminidase/uso terapêutico , Recém-Nascido , Fenótipo , Gravidez , Gestantes , Nascimento Prematuro/tratamento farmacológico , Reprodutibilidade dos Testes , Natimorto , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae , Suécia/epidemiologia , Virulência/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
7.
J Med Internet Res ; 24(5): e30073, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35503653

RESUMO

BACKGROUND: Although text messaging has the potential to be the core intervention modality, it is often used as an adjunct only. To improve health and alleviate the distress related to insomnia, pain, and dysregulated eating of people living in urban areas, text messaging-based mindfulness-based interventions were designed and evaluated in 3 randomized controlled trials. OBJECTIVE: This study investigated the effectiveness and mediating mechanisms of text messaging-based mindfulness-based interventions for people with distress related to insomnia, pain, or dysregulated eating. METHODS: In these trials, 333, 235, and 351 participants were recruited online and randomized to intervention and wait-list control conditions for insomnia, pain, and dysregulated eating, respectively. Participants experienced 21 days of intervention through WhatsApp Messenger. Participants completed pre-, post-, 1-month follow-up, and 3-month follow-up self-report questionnaires online. The retention rates at postmeasurements were 83.2% (139/167), 77.1% (91/118), and 72.9% (129/177) for intervention groups of insomnia, pain, and dysregulated eating, respectively. Participants' queries were answered by a study technician. Primary outcomes included insomnia severity, presleep arousal, pain intensity, pain acceptance, and eating behaviors. Secondary outcomes included mindfulness, depression, anxiety, mental well-being, and functional impairments. Mindfulness, dysfunctional beliefs and attitudes about sleep, pain catastrophizing, and reactivity to food cues were hypothesized to mediate the relationship between the intervention and outcomes. RESULTS: For all 3 studies, the intervention groups showed significant improvement on most outcomes at 1-month follow-up compared to their respective wait-list control groups; some primary outcomes (eg, insomnia, pain, dysregulated eating indicators) and secondary outcomes (eg, depression, anxiety symptoms) were sustained at 3-month follow-up. Medium-to-large effect sizes were found at postassessments in most outcomes in all studies. In the intervention for insomnia, mediation analyses showed that dysfunctional beliefs and attitudes about sleep mediated the effect of the intervention on all primary outcomes and most secondary outcomes at both 1-month and 3-month follow-ups, whereas mindfulness mediated the intervention effect on presleep arousal at 1-month and 3-month follow-ups. In the intervention for pain, pain catastrophizing mediated the effect of intervention on pain intensity and functioning at both 1-month and 3-month follow-ups, whereas mindfulness only mediated the effect of intervention on anxiety and depressive symptoms. In the intervention for dysregulated eating, power of food mediated the effect of intervention on both uncontrolled and emotional eating at both 1-month and 3-month follow-ups and mindfulness was found to mediate the effect on depressive symptoms at both 1-month and 3-month follow-ups. CONCLUSIONS: These 3 studies converged and provided empirical evidence that mindfulness-based interventions delivered through text messaging are effective in improving distress related to sleep, pain, and dysregulated eating. Text messaging has the potential to be a core intervention modality to improve various common health outcomes for people living a fast-paced lifestyle. TRIAL REGISTRATION: Clinical Research and Biostatistics Clinical Trials Registry CUHK_CCRB00559; https://tinyurl.com/24rkwarz.


Assuntos
Atenção Plena , Aplicativos Móveis , Distúrbios do Início e da Manutenção do Sono , Envio de Mensagens de Texto , Humanos , Dor , Ensaios Clínicos Controlados Aleatórios como Assunto , Distúrbios do Início e da Manutenção do Sono/terapia
8.
J Med Internet Res ; 23(12): e26733, 2021 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-34889760

RESUMO

BACKGROUND: Although social networking services (SNSs) have become popular among young people, problematic SNS use has also increased. However, little is known about SNS addiction and its association with SNS use patterns and mental health status. OBJECTIVE: This study aims to test the mediating role of SNS addiction between SNS use patterns and mental health status among Chinese university students in Hong Kong (HK). METHODS: An online cross-sectional survey was conducted using a convenience sampling method. In total, 533 university students (323 [66.9%] female, mean age [SD]=20.87 [2.68] years) were recruited from February to March 2019. Multiple linear regression was used to assess the association between SNS use and SNS addiction. Structural equation modeling (SEM) was performed to examine the pathways and associations among SNS use, SNS addiction, psychosocial status, and mental health status (including anxiety and depressive symptoms). RESULTS: A longer time spent on SNSs per day (>3 h), a longer time spent on each SNS access (≥31 min), a higher frequency of SNS access (≤every 30 min), a longer duration of SNS use before sleeping (≥61 min), and a shorter duration from waking to first SNS use (≤5 min) were significantly associated with a higher level of SNS addiction (adjusted beta [aß]=6.03, 95% CI 4.66-7.40; aß=4.99, 95% CI 3.14-6.83; aß=5.89, 95% CI 4.14-7.64; aß=5.92, 95% CI 4.19-7.65; and aß=3.27, 95% CI 1.73-4.82, respectively). SEM showed a significant mediating effect of SNS addiction in the relationship between SNS use and psychosocial status, and mental health status, including an indirect effect (ß=0.63, 95% CI 0.37-0.93) and the total effect (ß=0.44, 95% CI 0.19-0.72), while the direct effect was insignificant (ß=-0.19, 95% CI -0.49 to 0.08). CONCLUSIONS: SNS use patterns were associated with SNS addiction, and SNS addiction mediated the associations between SNS use, psychosocial status, and mental health status of Chinese university students in HK. The findings suggest that screening for and addressing excessive SNS use are needed to prevent SNS addiction and mental distress among young people.


Assuntos
Rede Social , Universidades , Adolescente , Pré-Escolar , Estudos Transversais , Feminino , Nível de Saúde , Hong Kong/epidemiologia , Humanos , Análise de Classes Latentes , Estudantes
9.
Transfus Apher Sci ; 59(4): 102780, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32505439

RESUMO

Indications for therapeutic and donor apheresis continue to increase and expand into new domains of therapy. The level and amount of apheresis education in residency programs remains heterogeneous, which may translate into varying degrees of clinical confidence in providing care. The purpose of this study was to assess Canadian clinicians' perceptions of their apheresis training in order to help demonstrate a need for a concrete apheresis education in residency curricula. A 22-question survey was distributed to Canadian graduates who recently completed training (2013-2017) in the following specialties: hematology, nephrology, transfusion medicine, and hematologic pathology. Questions regarding clinician perception of their training were asked using a Likert scale. Fifty-seven survey responses (32% response rate) were obtained from recent graduates from hematology (29/57, 51%), nephrology (21/57, 37%), hematologic pathology (4/57, 7%) and transfusion medicine (3/57, 5%). Although most respondents (68%) received some form of apheresis exposure during residency, only 23% reported a formal apheresis rotation. Only 40% felt that the amount of time devoted to apheresis education was sufficient, and only four respondents (7%) felt confident providing independent apheresis care at the end of training. Overall, these findings suggest that a common, dedicated apheresis curriculum in these training programs could possibly increase knowledge and competence of trainees, and provide a more solid foundation in apheresis for future practice.


Assuntos
Remoção de Componentes Sanguíneos/métodos , Internato e Residência/métodos , Avaliação das Necessidades/estatística & dados numéricos , Canadá , Humanos , Inquéritos e Questionários
10.
Am J Primatol ; 82(2): e23093, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31930746

RESUMO

Ecoimmunological patterns and processes remain understudied in wild primates, in part because of the lack of noninvasive methods to measure immunity. Secretory immunoglobulin A (sIgA) is the most abundant antibody present at mammalian mucosal surfaces and provides an important first line of defense against pathogens. Recent studies show that sIgA can be measured noninvasively in feces and is a good marker of mucosal immunity. Here we validated a commercial ELISA kit to measure fecal IgA in baboons, tested the robustness of its results to variation in collection and storage conditions, and developed a cost-effective in-house ELISA for baboon fecal IgA. Using data from the custom ELISA, we assessed the relationship between fecal IgA concentrations and gastrointestinal parasite burden, and tested how sex, age, and reproductive effort predict fecal IgA in wild baboons. We find that IgA concentrations can be measured in baboon feces using an in-house ELISA and are highly correlated to the values obtained with a commercial kit. Fecal IgA concentrations are stable when extracts are stored for up to 22 months at -20°C. Fecal IgA concentrations were negatively correlated with parasite egg counts (Trichuris trichiura), but not parasite richness. Fecal IgA did not vary between the sexes, but for males, concentrations were higher in adults versus adolescents. Lactating females had significantly lower fecal IgA than pregnant females, but neither pregnant nor lactating female concentrations differed significantly from cycling females. Males who engaged in more mate-guarding exhibited similar IgA concentrations to those who engaged in little mate-guarding. These patterns may reflect the low energetic costs of mucosal immunity, or the complex dependence of IgA excretion on individual condition. Adding a noninvasive measure of mucosal immunity will promote a better understanding of how ecology modulates possible tradeoffs between the immune system and other energetically costly processes in the wild.


Assuntos
Ensaio de Imunoadsorção Enzimática/veterinária , Imunidade nas Mucosas , Imunoglobulina A/análise , Papio anubis/imunologia , Papio cynocephalus/imunologia , Manejo de Espécimes/veterinária , Fatores Etários , Animais , Animais Selvagens/imunologia , Animais de Zoológico/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Quênia , Masculino , Doenças dos Macacos/imunologia , Doenças dos Macacos/parasitologia , North Carolina , Reprodução , Fatores Sexuais , Manejo de Espécimes/métodos , Tricuríase/imunologia , Tricuríase/parasitologia , Tricuríase/veterinária , Trichuris/fisiologia
11.
Appl Environ Microbiol ; 85(16)2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31201276

RESUMO

Research on the role of diet on gut and systemic health has led to considerable interest toward identifying novel therapeutic modulators of the gut microbiome, including the use of prebiotics and probiotics. However, various host responses have often been reported among many clinical trials. This is in part due to competitive exclusion as a result of the absence of ecological niches as well as host-mediated constraints via colonization resistance. In this research, we developed a novel in vitro enrichment (IVE) method for isolating autochthonous strains that can function as synergistic synbiotics and overcome these constraints. The method relied on stepwise in vitro fecal fermentations to enrich for and isolate Bifidobacterium strains that ferment the prebiotic xylooligosaccharide (XOS). We subsequently isolated Bifidobacterium longum subsp. longum CR15 and then tested its establishment in 20 unique fecal samples with or without XOS. The strain was established in up to 18 samples but only in the presence of XOS. Our findings revealed that the IVE method is suitable for isolating potential synergistic probiotic strains that possess the genetic and biochemical ability to ferment specific prebiotic substrates. The IVE method can be used as an initial high-throughput screen for probiotic selection and isolation prior to further characterization and in vivo tests.IMPORTANCE This study describes an in vitro enrichment method to formulate synergistic synbiotics that have potential for establishing autochthonous strains across multiple individuals. The rationale for this approach-that the chance of survival of a bacterial strain is improved by providing it with its required resources-is based on classic ecological theory. From these experiments, a human-derived strain, Bifidobacterium longum subsp. longum CR15, was identified as a xylooligosaccharide (XOS) fermenter in fecal environments and displayed synergistic effects in vitro The high rate of strain establishment observed in this study provides a basis for using synergistic synbiotics to overcome the responder/nonresponder phenomenon that occurs frequently in clinical trials with probiotic and prebiotic interventions. In addition, this approach can be applied in other protocols that require enrichment of specific bacterial populations prior to strain isolation.


Assuntos
Bifidobacterium/isolamento & purificação , Bifidobacterium/metabolismo , Simbióticos/análise , Adulto , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bifidobacterium/genética , Bifidobacterium/crescimento & desenvolvimento , Fezes/microbiologia , Fermentação , Microbioma Gastrointestinal , Glucuronatos/metabolismo , Humanos , Oligossacarídeos/metabolismo , Filogenia , Adulto Jovem
13.
J Chem Phys ; 149(7): 072311, 2018 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-30134726

RESUMO

Calorimetric studies of protein-ligand binding sometimes yield thermodynamic data that are difficult to understand. Today, molecular simulations can be used to seek insight into such calorimetric puzzles, and, when simulations and experiments diverge, the results can usefully motivate further improvements in computational methods. Here, we apply near-millisecond duration simulations to estimate the relative binding enthalpies of four peptidic ligands with the Grb2 SH2 domain. The ligands fall into matched pairs, where one member of each pair has an added bond that preorganizes the ligand for binding and thus may be expected to favor binding entropically, due to a smaller loss in configurational entropy. Calorimetric studies have shown that the constrained ligands do in fact bind the SH2 domain more tightly than the flexible ones, but, paradoxically, the improvement in affinity for the constrained ligands is enthalpic, rather than entropic. The present enthalpy calculations yield the opposite trend, as they suggest that the flexible ligands bind more exothermically. Additionally, the small relative binding enthalpies are found to be balances of large differences in the energies of structural components such as ligand and the binding site residues. As a consequence, the deviations from experiment in the relative binding enthalpies represent small differences between these large numbers and hence may be particularly susceptible to error, due, for example, to approximations in the force field. We also computed first-order estimates of changes in configurational entropy on binding. These too are, arguably, paradoxical, as they tend to favor binding of the flexible ligands. The paradox is explained in part by the fact that the more rigid constrained ligands reduce the entropy of binding site residues more than their flexible analogs do, at least in the simulations. This result offers a rather general counterargument to the expectation that preorganized ligands should be associated with more favorable binding entropies, other things being equal.


Assuntos
Proteína Adaptadora GRB2/química , Oligopeptídeos/química , Termodinâmica , Ligantes , Simulação de Dinâmica Molecular , Análise de Componente Principal , Ligação Proteica , Conformação Proteica , Água/química , Domínios de Homologia de src
14.
Pediatr Hematol Oncol ; 35(1): 45-51, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29652549

RESUMO

Glycogen storage disease (GSD) type 1 is a rare autosomal recessive inherited condition. The 1b subtype comprises the minority of cases, with an estimated prevalence of 1 in 500,000 children. Patients with glycogen storage disease type 1b are often treated with granulocyte colony stimulating factor (G-CSF) for prolonged periods to improve symptoms of inflammatory bowel disease (IBD) and in the face of severe neutropenia to decrease risk of infection. Long-term G-CSF treatment may result in an increased risk of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) possibly due to increased marrow stress resulting in telomere shortening. To our knowledge, there have been two published cases of AML in GSD type 1b patients following long-term G-CSF exposure. Here, we report two further cases of AML/MDS-related changes in patients GSD type 1b treated with G-CSF. One patient developed AML with complex karyotype after 20 years of G-CSF treatment. The second patient was found to have short telomeres after 10 years of G-CSF exposure, but no evidence of acute leukemia at present. The third patient developed AML/MDS after 25 years of G-CSF use, with short telomeres prior to bone marrow transplant. Together these cases suggest that GSD type 1b patients with prolonged G-CSF exposure may be at an increased risk of MDS/AML states associated with G-CSF-induced shortened telomeres. We recommend that any GSD1b patients with prolonged G-CSF should have routine telomere assessments with monitoring for MDS if telomere shortening is observed, and with particular attention warranted if there is unexplained loss of G-CSF responsiveness.


Assuntos
Doença de Depósito de Glicogênio Tipo I , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Leucemia Mieloide Aguda , Homeostase do Telômero , Criança , Pré-Escolar , Feminino , Doença de Depósito de Glicogênio Tipo I/tratamento farmacológico , Doença de Depósito de Glicogênio Tipo I/genética , Doença de Depósito de Glicogênio Tipo I/metabolismo , Fator Estimulador de Colônias de Granulócitos/efeitos adversos , Humanos , Lactente , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Masculino , Fatores de Tempo
15.
J Am Chem Soc ; 139(24): 8138-8145, 2017 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-28532152

RESUMO

In this paper, we report on the noteworthy attractive interaction between organic azides and the portal carbonyls of cucurbiturils. Five homologous bis-α,ω-azidoethylammonium alkanes were prepared, where the number of methylene groups between the ammonium groups ranges from 4 to 8. Their interactions with cucurbit[6]uril were studied by NMR spectroscopy, IR spectroscopy, X-ray crystallography, and computational methods. Remarkably, while the distance between the portal plane and most atoms at the guest end groups increases progressively with the molecular size, the ß-nitrogen atoms maintain a constant distance from the portal plane in all homologues, pointing at a strong attractive interaction between the azide group and the portal. Both crystallography and NMR support a specific electrostatic interaction between the carbonyl and the azide ß-nitrogen, which stabilizes the canonical resonance form with positive charge on the ß-nitrogen and negative charge on the γ-nitrogen. Quantum computational analyses strongly support electrostatics, in the form of orthogonal dipole-dipole interaction, as the main driver for this attraction. The alternative mechanism of n → π* orbital delocalization does not seem to play a significant role in this interaction. The computational studies also indicate that the interaction is not limited to azides, but generalizes to other isoelectronic heteroallene functions, such as isocyanate and isothiocyanate. This essentially unexploited attractive interaction could be more broadly utilized as a tool not only in relation to cucurbituril chemistry, but also for the design of novel supramolecular architectures.


Assuntos
Azidas/química , Compostos Macrocíclicos/química , Azidas/síntese química , Cristalografia por Raios X , Modelos Moleculares , Teoria Quântica
16.
Med Educ ; 51(2): 158-173, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27862175

RESUMO

CONTEXT: While medical curricula were traditionally almost entirely comprised of bioscientific knowledge, widely accepted competency frameworks now make clear that physicians must be competent in far more than biomedical knowledge and technical skills. For example, of the influential CanMEDS roles, six are conceptually based in the social sciences and humanities (SSH). Educators frequently express uncertainty about what to teach in this area. This study concretely identifies the knowledge beyond bioscience needed to support the training of physicians competent in the six non-Medical Expert CanMEDS roles. METHODS: We interviewed 58 non-clinician university faculty members with doctorates in over 20 SSH disciplines. We abstracted our transcripts (meaning condensation, direct quotations) resulting in approximately 300 pages of data which we coded using top-down (by CanMEDS role) and bottom-up (thematically) approaches and analysed within a critical constructivist framework. Participants and clinicians with SSH PhDs member-checked and refined our results. RESULTS: Twelve interrelated themes were evident in the data. An understanding of epistemology, including the constructed nature of social knowledge, was seen as the foundational theme without which the others could not be taught or understood. Our findings highlighted three anchoring themes (Justice, Power, Culture), all of which link to eight more specific themes concerning future physicians' relationships to the world and the self. All 12 themes were cross-cutting, in that each related to all six non-Medical Expert CanMEDS roles. The data also provided many concrete examples of potential curricular content. CONCLUSIONS: There is a definable body of SSH knowledge that forms the academic underpinning for important physician competencies and is outside the experience of most medical educators. Curricular change incorporating such content is necessary if we are to strengthen the non-Medical Expert physician competencies. Our findings, particularly our cross-cutting themes, also provide a pedagogically useful mechanism for holistically teaching the underpinnings of physician competence. We are now implementing our findings into medical curricula.


Assuntos
Educação Médica/métodos , Ciências Humanas/educação , Ciências Sociais/educação , Competência Clínica/normas , Educação Baseada em Competências/métodos , Cultura , Humanos , Conhecimento , Papel do Médico , Poder Psicológico , Justiça Social/educação
17.
Int J Eat Disord ; 49(5): 499-506, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26712303

RESUMO

OBJECTIVE: Interpersonal difficulties among individuals with anorexia nervosa (AN) may stem in part due to misperceiving social cues. The current study investigated social functioning by comparing interpersonal self-efficacy, perceptions of dominance/submission (i.e., agency) and coldness/warmth (i.e., communion), and hypothetical behavioral reactions among individuals with and without AN. METHOD: Seventy-seven women (AN/Other Specified Feeding or Eating Disorder OSFED-AN n = 41, nonclinical comparison group n = 36) completed questionnaires assessing mood symptoms and interpersonal self-efficacy, followed by an experimental video-rating task in which they received critical feedback from job supervisors varying in degrees of agency and communion. RESULTS: AN respondents perceived more coldness overall, even after adjusting for differences in depression and anxiety symptoms, and tended to respond with coldness even to videos that they perceived as being warm. However, perceptual accuracies for agency were similar across groups. Interpersonal self-efficacy moderated the relationship between diagnostic status and behavioral responses: among those who felt competent being cold-submissive, AN respondents selected cold-submissive responses more frequently than did the nonclinical comparison group. DISCUSSION: Among those with AN symptoms, there may be a tendency toward social perceptual inaccuracies regarding communion and non-complementary cold behavioral responses. Results suggest that improving social perceptions may be a fruitful intervention target for enhancing interpersonal functioning among individuals with AN. © 2015 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:499-506).


Assuntos
Anorexia Nervosa/psicologia , Cognição/fisiologia , Percepção Social , Adolescente , Adulto , Idoso , Ansiedade/etiologia , Estudos de Casos e Controles , Depressão/etiologia , Emoções/fisiologia , Retroalimentação Psicológica , Feminino , Humanos , Relações Interpessoais , Pessoa de Meia-Idade , Comportamento Social , Inquéritos e Questionários , Adulto Jovem
18.
Cancer ; 121(9): 1499-507, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25586788

RESUMO

BACKGROUND: The cure rate for childhood intracranial ependymoma is approximately 70% in the setting of a gross total resection followed by radiation, but management remains challenging in patients with residual disease. Therefore, robust biomarkers are needed to guide the development of new targeted therapy. The authors evaluated the expression of several biomarkers in pediatric intracranial ependymoma and observed that the expression of enhancer of zeste homolog 2 (EZH2), a polycomb complex protein involved in epigenetic regulation of gene expression, was independently associated with poor survival. METHODS: Tissue microarray immunostaining was performed on 180 ependymoma samples from 12 of 16 Canadian pediatric centers. Expression levels of EZH2, Ki-67, B lymphoma Moloney-murine leukemia virus insertion region 1 homolog, tumor protein 16 (P16), Y-box binding protein 1, phosphorylated protein kinase B (pAKT), and epidermal growth factor receptor were evaluated. Cox regression analyses were performed, and the Kaplan-Meier method was used to construct survival curves. RESULTS: EZH2 expressed in 16% of tumors was associated with inferior 5-year overall survival. Ki-67 and pAKT levels were associated with a poor outcome in patients with posterior fossa ependymoma, and the absence of P16 was associated with a poor outcome in patients with supratentorial ependymoma. Multivariate analysis revealed that younger age and EZH2 expression (95% confidence interval, 1.1-36.0) were independent markers of a poor prognosis. CONCLUSIONS: EZH2 is a novel, independent marker of a poor prognosis in patients with ependymoma, especially in those who have tumors located in the posterior fossa. EZH2, pAKT, and P16 are potential therapeutic targets, particularly for patients who have tumors in which standard gross total resection plus fractionated radiotherapy is not feasible.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/metabolismo , Ependimoma/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Adolescente , Neoplasias Encefálicas/mortalidade , Criança , Pré-Escolar , Proteína Potenciadora do Homólogo 2 de Zeste , Ependimoma/mortalidade , Feminino , Humanos , Lactente , Estimativa de Kaplan-Meier , Masculino , Análise Multivariada , Prognóstico , Modelos de Riscos Proporcionais , Estudos Retrospectivos
20.
Protein Expr Purif ; 104: 57-64, 2014 12.
Artigo em Inglês | MEDLINE | ID: mdl-25240855

RESUMO

In Gram-negative bacteria, the cell wall is surrounded by an outer membrane, the outer leaflet of which is comprised of charged lipopolysaccharide (LPS) molecules. Lipid A, a component of LPS, anchors this molecule to the outer membrane. UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a zinc-dependent metalloamidase that catalyzes the first committed step of biosynthesis of Lipid A, making it a promising target for antibiotic therapy. Formation of soluble aggregates of Pseudomonas aeruginosa LpxC protein when overexpressed in Escherichia coli has limited the availability of high quality protein for X-ray crystallography. Expression of LpxC in the presence of an inhibitor dramatically increased protein solubility, shortened crystallization time and led to a high-resolution crystal structure of LpxC bound to the inhibitor. However, this approach required large amounts of compound, restricting its use. To reduce the amount of compound needed, an overexpression strain of E. coli was created lacking acrB, a critical component of the major efflux pump. By overexpressing LpxC in the efflux deficient strain in the presence of LpxC inhibitors, several structures of P. aeruginosa LpxC in complex with different compounds were solved to accelerate structure-based drug design.


Assuntos
Amidoidrolases/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Escherichia coli/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Pseudomonas aeruginosa/enzimologia , Amidoidrolases/antagonistas & inibidores , Amidoidrolases/genética , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Catálise , Cromatografia Líquida , Cristalografia por Raios X , Escherichia coli , Expressão Gênica , Espectrometria de Massas , Conformação Proteica , Zinco/química , Zinco/metabolismo
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