Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Acta Psychol (Amst) ; 243: 104135, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38237472

RESUMO

Detecting participants not exerting sufficient effort (e.g., answering randomly; termed 'insufficient effort responding' or IER) in self-report surveys is crucial but intricate. Challenges of appropriately removing IER resemble a surgeon excising necrotic tissue without being inadequate, excessive, or incorrect. Current cutoff criteria for stopping the elimination of suspected IER responses are often arbitrary. This study proposes an external criterion strategy to identify the optimal cutoff values for various IER detection methods. We investigated the change in correlations between the IER-containing scale (e.g., motivation) and the external criterion (e.g., academic performance, socioeconomic status index, or another questionnaire scale) utilizing simulated and authentic international survey data. The findings revealed that the stopping rule and consequently, the optimal cutoff values for IER detection methods, can be accurately identified by locating the inflection point in the correlation plot with the external criterion. Practical strategies are recommended for applied researchers.


Assuntos
Inquéritos e Questionários , Humanos , Autorrelato
2.
Semin Perinatol ; 47(8): 151844, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37852893

RESUMO

The healthcare industry makes up 4.6 % of greenhouse gas (GHS) emissions worldwide. Although it is not known what proportion of GHGs come from obstetric and newborn units, newborns and pregnant individuals are likely to face some of the largest consequences from climate change. We review the literature in the areas of decarbonization on labor and delivery (L&D) and neonatal units and describe innovations from the fields of surgery and anesthesia. Best practices for L&D include refining disposable equipment packs, decreasing the use of single-use medical devices, adequately triaging waste, and decreasing the use of potent anesthetic gases such as nitrous oxide and desflurane. In neonatal settings, similarly triaging waste and decreasing the use of plastics containing endocrine disrupting chemicals can lower the carbon and environmental footprint and improve neonatal health. Additionally, avoiding unnecessary cesarean deliveries and increasing breastfeeding practices are also likely to improve the carbon footprint of L&D and neonatal units.


Assuntos
Anestésicos Inalatórios , Gases de Efeito Estufa , Recém-Nascido , Humanos , Anestésicos Inalatórios/análise , Óxido Nitroso/análise , Gases de Efeito Estufa/análise
3.
Biology (Basel) ; 12(2)2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36829435

RESUMO

Boosting trophic support to striatal neurons by increasing levels of brain-derived neurotrophic factor (BDNF) has been considered as a target for therapeutic intervention for several neurodegenerative diseases, including Huntington's disease (HD). To aid in the implementation of such a strategy, a thorough understanding of BDNF cortical-striatal transport is critical to help guide its strategic delivery. In this manuscript, we investigate the dynamic behavior of BDNF transport along the cortical-striatal axis in Q140 primary neurons, a mouse model for HD. We examine this by using single-molecule labeling of BDNF conjugated with quantum dots (QD-BDNF) to follow the transport along the cortical-striatal axis in a microfluidic chamber system specifically designed for the co-culture of cortical and striatal primary neurons. Using this approach, we observe a defect of QD-BDNF transport in Q140 neurons. Our study demonstrates that QD-BDNF transport along the cortical-striatal axis involves the impairment of anterograde transport within axons of cortical neurons, and of retrograde transport within dendrites of striatal neurons. One prominent feature we observe is the extended pause time of QD-BDNF retrograde transport within Q140 striatal dendrites. Taken together, these finding support the hypothesis that delinquent spatiotemporal trophic support of BDNF to striatal neurons, driven by impaired transport, may contribute to the pathogenesis of HD, providing us with insight into how a BDNF supplementation therapeutic strategy may best be applied for HD.

4.
Transplantation ; 107(5): 1172-1179, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36595026

RESUMO

BACKGROUND: Donor-specific antibodies (DSAs) have been associated with antibody-mediated rejection, chronic lung allograft dysfunction (CLAD), and increased mortality in lung transplant recipients. Our center performs transplants in the presence of DSA, and we sought to evaluate the safety of this practice with respect to graft loss, CLAD onset, and primary graft dysfunction (PGD). METHODS: We reviewed recipients transplanted from 2010 to 2017, classifying them as DSA positive (DSA + ) or negative. We used Kaplan-Meier estimation to test the association between DSA status and time to death or retransplant and time to CLAD onset. We further tested associations with severe PGD and rejection in the first year using logistic regression and Fisher exact testing. RESULTS: Three hundred thirteen patients met inclusion criteria, 30 (10%) of whom were DSA + . DSA + patients were more likely to be female, bridged to transplant, and receive induction therapy. There was no association between DSA status and time to death or retransplant (log rank P = 0.581) nor death-censored time to CLAD onset (log rank P = 0.278), but DSA + patients were at increased risk of severe PGD (odds ratio 2.88; 95% confidence interval, 1.10-7.29; P = 0.031) and more frequent antibody-mediated rejection in the first posttransplant year. CONCLUSIONS: Crossing DSA at time of lung transplant was not associated with an increased risk of death or CLAD in our cohort, but patients developed severe PGD and antibody-mediated rejection more frequently. However, these risks are likely manageable when balanced against the benefits of expanded access for sensitized candidates.


Assuntos
Isoanticorpos , Transplante de Pulmão , Humanos , Feminino , Masculino , Rejeição de Enxerto/prevenção & controle , Estudos Retrospectivos , Transplante de Pulmão/efeitos adversos , Pulmão , Doadores de Tecidos , Antígenos HLA
5.
Biol Open ; 12(1)2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36524613

RESUMO

Stem cells cycle between periods of quiescence and proliferation to promote tissue health. In Drosophila ovaries, quiescence to proliferation transitions of follicle stem cells (FSCs) are exquisitely feeding-dependent. Here, we demonstrate feeding-dependent induction of follicle cell differentiation markers, eyes absent (Eya) and castor (Cas) in FSCs, a patterning process that does not depend on proliferation induction. Instead, FSCs extend micron-scale cytoplasmic projections that dictate Eya-Cas patterning. We identify still life and sickie as necessary and sufficient for FSC projection growth and Eya-Cas induction. Our results suggest that sequential, interdependent events establish long-term differentiation patterns in follicle cell precursors, independently of FSC proliferation induction.


Assuntos
Proteínas de Drosophila , Ovário , Animais , Feminino , Ovário/metabolismo , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Divisão Celular , Diferenciação Celular
6.
Respir Med ; 206: 107093, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36549515

RESUMO

BACKGROUND: Indwelling pleural catheters (IPCs) are a mainstay therapy for malignant pleural effusions (MPEs). Many patients treated with IPCs achieve pleurodesis. We aimed to identify the effect of systemic therapies for non-small cell lung cancer (NSCLC) on IPC removal in patients with associated MPEs. METHODS: We completed a retrospective cohort study of adult IPC recipients with metastatic NSCLC at the pleural effusion clinic at the Royal Alexandra Hospital from 2009 to 2020. We used logistic regression to assess the rates of IPC removal and Cox regression to assess the time to IPC removal. RESULTS: 232 patients met inclusion criteria with 248 IPCs reviewed. The overall pleurodesis rate was 42.7% with a median time to pleurodesis of 68 (IQR 38-140) days. In univariate analysis, chemotherapy (OR 1.86, CI 0.99-3.49) and epidermal growth factor receptor (EGFR) targeted therapy (OR 3.81, CI 1.86-7.79) were associated with higher rates of pleurodesis. In multivariate analysis, increased rates of pleurodesis were associated with an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of ≤2 (OR 4.82, CI 2.24-10.37) and EGFR targeted therapy (OR 3.87, CI 1.80-8.32). Earlier IPC removal was associated with EGFR targeted therapy in both univariate (HR 1.84, CI 1.20-2.83) and multivariate analysis (HR 1.86, CI 1.19-2.92). CONCLUSIONS: Treatment with EGFR targeted therapy is associated with increased rates and earlier removal of IPC in patients with NSCLC in our cohort. Further large cohort studies are required to determine if this relationship persists.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Derrame Pleural Maligno , Adulto , Humanos , Derrame Pleural Maligno/terapia , Carcinoma Pulmonar de Células não Pequenas/complicações , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Estudos Retrospectivos , Talco , Neoplasias Pulmonares/complicações , Neoplasias Pulmonares/terapia , Cateteres de Demora/efeitos adversos , Pleurodese , Drenagem , Imunoterapia
7.
PLoS One ; 17(12): e0279913, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36584183

RESUMO

BACKGROUND: Women with HIV (WWH) face heightened risks of heart failure; however, insights on immune/inflammatory pathways potentially contributing to left ventricular (LV) systolic dysfunction among WWH remain limited. SETTING: Massachusetts General Hospital, Boston, Massachusetts. METHODS: Global longitudinal strain (GLS) is a sensitive measure of LV systolic function, with lower cardiac strain predicting incident heart failure and adverse heart failure outcomes. We analyzed relationships between GLS (cardiovascular magnetic resonance imaging) and monocyte activation (flow cytometry) among 20 WWH and 14 women without HIV. RESULTS: WWH had lower GLS compared to women without HIV (WWH vs. women without HIV: 19.4±3.0 vs. 23.1±1.9%, P<0.0001). Among the whole group, HIV status was an independent predictor of lower GLS. Among WWH (but not among women without HIV), lower GLS related to a higher density of expression of HLA-DR on the surface of CD14+CD16+ monocytes (ρ = -0.45, P = 0.0475). Further, among WWH, inflammatory monocyte activation predicted lower GLS, even after controlling for CD4+ T-cell count and HIV viral load. CONCLUSIONS: Additional studies among WWH are needed to examine the role of inflammatory monocyte activation in the pathogenesis of lower GLS and to determine whether targeting this immune pathway may mitigate risks of heart failure and/or adverse heart failure outcomes. TRIAL REGISTRATION: Clinical trials.gov registration: NCT02874703.


Assuntos
Infecções por HIV , Insuficiência Cardíaca , Disfunção Ventricular Esquerda , Humanos , Feminino , Monócitos , Coração , Função Ventricular Esquerda/fisiologia , Volume Sistólico/fisiologia
8.
J Infect Dis ; 226(10): 1823-1833, 2022 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-35856671

RESUMO

BACKGROUND: Persistent immune activation is thought to contribute to heightened atherosclerotic cardiovascular disease (ASCVD) risk among people with human immunodeficiency virus (PWH). METHODS: Participants (≥18 years) with or without human immunodeficiency virus (HIV) and without history of clinical ASCVD were enrolled. We hypothesized that increased macrophage-specific arterial infiltration would relate to plaque composition and systemic immune activation among PWH. We applied a novel targeted molecular imaging approach (technetium-99m [99mTc]-tilmanocept single photon emission computed tomography [SPECT]/CT) and comprehensive immune phenotyping. RESULTS: Aortic 99mTc-tilmanocept uptake was significantly higher among PWH (n = 20) than participants without HIV (n = 10) with similar 10-year ASCVD risk (P = .02). Among PWH, but not among participants without HIV, noncalcified aortic plaque volume related directly to aortic 99mTc-tilmanocept uptake at different uptake thresholds. An interaction (P = .001) was seen between HIV status and noncalcified plaque volume, but not calcified plaque (P = .83). Systemic levels of caspase-1 (P = .004), CD14-CD16+ (nonclassical/patrolling/homing) monocytes (P = .0004) and CD8+ T cells (P = .005) related positively and CD4+/CD8+ T-cell ratio (P = .02) inversely to aortic 99mTc-tilmanocept uptake volume. CONCLUSIONS: Macrophage-specific arterial infiltration was higher among PWH and related to noncalcified aortic plaque volume only among PWH. Key systemic markers of immune activation relating to macrophage-specific arterial infiltration may contribute to heightened ASCVD risk among PWH. CLINICAL TRIALS REGISTRATION: NCT02542371.


Assuntos
Aterosclerose , Infecções por HIV , Placa Aterosclerótica , Humanos , Placa Aterosclerótica/diagnóstico por imagem , Infecções por HIV/tratamento farmacológico , Macrófagos , HIV
10.
J Genet Couns ; 31(4): 976-988, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35416393

RESUMO

Genetic counselors (GCs) and healthcare interpreters (HIs) are key members of the healthcare team when providing genetic counseling services to patients with Limited English Proficiency (LEP); however, the working relationship between GCs and HIs and the role each member plays within a genetic counseling session is unclear. Previous studies assessing this relationship have been qualitative and limited in sample size (Agather et al., 2018, Journal of Genetic Counseling, 26, 1388; Krieger et al., 2018, Journal of Genetic Counseling, 26, 1388; Lara-Otero et al., 2019, Health Communication, 34, 1608; Rosenbaum et al., 2020, Journal of Genetic Counseling, 29, 352). This study utilized a quantitative approach to allow for sampling of larger populations and to simultaneously understand current perspectives of GCs and HIs regarding each other's and their own roles within a genetic counseling session. GC and HI participants from the United States were recruited via email to complete an online survey with questions regarding interactions prior to a session, roles during a session, and opportunities for collaboration and constraints in the working relationship. Descriptive and inferential statistics were utilized to analyze responses of GCs and HIs. 130 GC and 40 HI participants were included in this study. There were statistically significant differences (p < .001) in responses between GC and HI participants on the expected distribution of roles during a session in advocacy, psychosocial and cultural domains. Additionally, this study identified that HI desired resources and training regarding genetics and genetic counseling are currently not being met. To our knowledge, this is the largest study to simultaneously survey GC and HI perspectives on these topics. Our findings suggest the need for greater communication and collaboration between GCs and HIs to ensure high-quality care for patients with LEP. Integrating a pre-session meeting between the GC and HI for sessions with patients with LEP and increasing education for GCs and HIs on the roles each group brings into a session is warranted to optimize this collaborative relationship and patient care.


Assuntos
Conselheiros , Proficiência Limitada em Inglês , Pessoal Técnico de Saúde , Conselheiros/psicologia , Atenção à Saúde , Aconselhamento Genético/psicologia , Humanos , Estados Unidos
11.
STAR Protoc ; 2(2): 100592, 2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34169286

RESUMO

We have outlined the approach of visualizing autophagy specifically in the epithelial follicle stem cells of the Drosophila ovary using the LysoTracker dye. The advantage of using this protocol is that it details several techniques, including ovary dissection, immunofluorescence, and western blotting, that positively identify autophagy changes in a very small population of cells. One of the limitations of this protocol is that it needs to be combined with other genetic manipulations and positive markers of the autophagy pathway. For complete details on the use and execution of this protocol, please refer to Singh et al., (2018).


Assuntos
Autofagia , Rastreamento de Células , Folículo Ovariano/citologia , Células-Tronco/citologia , Animais , Drosophila , Células Epiteliais/citologia , Feminino , Microscopia Confocal
12.
Proc Natl Acad Sci U S A ; 116(37): 18423-18428, 2019 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-31444302

RESUMO

During prophase I of meiosis, chromosomes become organized as loop arrays around the proteinaceous chromosome axis. As homologous chromosomes physically pair and recombine, the chromosome axis is integrated into the tripartite synaptonemal complex (SC) as this structure's lateral elements (LEs). While the components of the mammalian chromosome axis/LE-including meiosis-specific cohesin complexes, the axial element proteins SYCP3 and SYCP2, and the HORMA domain proteins HORMAD1 and HORMAD2-are known, the molecular organization of these components within the axis is poorly understood. Here, using expansion microscopy coupled with 2-color stochastic optical reconstruction microscopy (STORM) imaging (ExSTORM), we address these issues in mouse spermatocytes at a resolution of 10 to 20 nm. Our data show that SYCP3 and the SYCP2 C terminus, which are known to form filaments in vitro, form a compact core around which cohesin complexes, HORMADs, and the N terminus of SYCP2 are arrayed. Overall, our study provides a detailed structural view of the meiotic chromosome axis, a key organizational and regulatory component of meiotic chromosomes.


Assuntos
Cromossomos de Mamíferos/química , Cromossomos de Mamíferos/metabolismo , Microscopia/métodos , Animais , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Masculino , Mamíferos/genética , Meiose , Camundongos , Espermatócitos/metabolismo , Coloração e Rotulagem , Complexo Sinaptonêmico/metabolismo
13.
Clin Nephrol Case Stud ; 6: 21-26, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30206511

RESUMO

. Sarcoidosis is a rare autoimmune disease resulting in formation of non-necrotizing "non-caseating" granulomas generally in the lung. The disease classically strikes African American females in their fourth and fifth decades. The resulting hypercalcemia is a result of 1-α hydroxylase overexpression in granulomas with increased 1,25-dihydroxy vitamin D levels. This phenomenon can also be observed in mycobacterial and fungal infections that produce granulomas in infected patients. Thus, chronic infectious diseases are part of differential diagnosis of granulomatous processes. We present an elderly Caucasian female who presented with hypercalcemia with serum calcium of 11 - 14 mg/dL and an elevated ionized calcium of 1.4 - 1.5 mmol/L. Initially cholecalciferol supplements were stopped, but hypercalcemia persisted for more than 2 months. 1,25-dihydroxy vitamin D levels were markedly elevated with low normal 25-hydroxy vitamin D levels, angiotensin-converting enzyme levels were also high, and chest computed tomography (CT) imaging was negative for any lymphadenopathy (including perihilar lymphadenopathy). Malignancy and infectious workups were negative for fungal and mycobacterial infections. Positron emission tomography revealed several small lymph nodes in right upper lobe of lung, and biopsy of bone marrow and lung lymph-nodes revealed non-caseating granulomata. We present an atypical case of occult sarcoidosis presenting mainly with biochemical findings without any definitive imaging findings, making diagnosis a clinical challenge.

14.
J Neurosci ; 35(24): 9122-36, 2015 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-26085635

RESUMO

The extinction of learned fear is a hippocampus-dependent process thought to embody new learning rather than erasure of the original fear memory, although it is unknown how these competing contextual memories are represented in the hippocampus. We previously demonstrated that contextual fear conditioning results in hippocampal place cell remapping and long-term stabilization of novel representations. Here we report that extinction learning also induces place cell remapping in C57BL/6 mice. Specifically, we observed cells that preferentially remapped during different stages of learning. While some cells remapped in both fear conditioning and extinction, others responded predominantly during extinction, which may serve to modify previous representations as well as encode new safe associations. Additionally, we found cells that remapped primarily during fear conditioning, which could facilitate reacquisition of the original fear association. Moreover, we also observed cells that were stable throughout learning, which may serve to encode the static aspects of the environment. The short-term remapping observed during extinction was not found in animals that did not undergo fear conditioning, or when extinction was conducted outside of the conditioning context. Finally, conditioning and extinction produced an increase in spike phase locking to the theta and gamma frequencies. However, the degree of remapping seen during conditioning and extinction only correlated with gamma synchronization. Our results suggest that the extinction learning is a complex process that involves both modification of pre-existing memories and formation of new ones, and these traces coexist within the same hippocampal representation.


Assuntos
Potenciais de Ação/fisiologia , Aprendizagem da Esquiva/fisiologia , Extinção Psicológica/fisiologia , Medo/fisiologia , Hipocampo/citologia , Hipocampo/fisiologia , Animais , Medo/psicologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
15.
Hippocampus ; 24(12): 1533-48, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25045084

RESUMO

Compared with the dorsal hippocampus, relatively few studies have characterized neuronal responses in the ventral hippocampus. In particular, it is unclear whether and how cells in the ventral region represent space and/or respond to contextual changes. We recorded from dorsal and ventral CA1 neurons in freely moving mice exposed to manipulations of visuospatial and olfactory contexts. We found that ventral cells respond to alterations of the visuospatial environment such as exposure to novel local cues, cue rotations, and contextual expansion in similar ways to dorsal cells, with the exception of cue rotations. Furthermore, we found that ventral cells responded to odors much more strongly than dorsal cells, particularly to odors of high valence. Similar to earlier studies recording from the ventral hippocampus in CA3, we also found increased scaling of place cell field size along the longitudinal hippocampal axis. Although the increase in place field size observed toward the ventral pole has previously been taken to suggest a decrease in spatial information coded by ventral place cells, we hypothesized that a change in spatial scaling could instead signal a shift in representational coding that preserves the resolution of spatial information. To explore this possibility, we examined population activity using principal component analysis (PCA) and neural location reconstruction techniques. Our results suggest that ventral populations encode a distributed representation of space, and that the resolution of spatial information at the population level is comparable to that of dorsal populations of similar size. Finally, through the use of neural network modeling, we suggest that the redundancy in spatial representation along the longitudinal hippocampal axis may allow the hippocampus to overcome the conflict between memory interference and generalization inherent in neural network memory. Our results indicate that ventral population activity is well suited for generalization across locations and contexts.


Assuntos
Região CA1 Hipocampal/fisiologia , Neurônios/fisiologia , Percepção Espacial/fisiologia , Potenciais de Ação , Animais , Sinais (Psicologia) , Eletrodos Implantados , Comportamento Exploratório/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Modelos Neurológicos , Redes Neurais de Computação , Odorantes , Percepção Olfatória/fisiologia , Análise de Componente Principal , Rotação , Processamento de Sinais Assistido por Computador , Memória Espacial/fisiologia
16.
Hippocampus ; 23(6): 451-66, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23460388

RESUMO

The study of fear memory is important for understanding various anxiety disorders in which patients experience persistent recollections of traumatic events. These memories often involve associations of contextual cues with aversive events; consequently, Pavlovian classical conditioning is commonly used to study contextual fear learning. The use of predator odor as a fearful stimulus in contextual fear conditioning has become increasingly important as an animal model of anxiety disorders. Innate fear responses to predator odors are well characterized and reliable; however, attempts to use these odors as unconditioned stimuli in fear conditioning paradigms have proven inconsistent. Here we characterize a contextual fear conditioning paradigm using coyote urine as the unconditioned stimulus. We found that contextual conditioning induced by exposure to coyote urine produces long-term freezing, a stereotypic response to fear observed in mice. This paradigm is context-specific and parallels shock-induced contextual conditioning in that it is responsive to extinction training and manipulations of predator odor intensity. Region-specific lesions of the dorsal and ventral hippocampus indicate that both areas are independently required for the long-term expression of learned fear. These results in conjunction with c-fos immunostaining data suggest that while both the dorsal and ventral hippocampus are required for forming a contextual representation, the ventral region also modulates defensive behaviors associated with predators. This study provides information about the individual contributions of the dorsal and ventral hippocampus to ethologically relevant fear learning.


Assuntos
Condicionamento Psicológico/fisiologia , Medo/fisiologia , Hipocampo/fisiologia , Odorantes , Animais , Coiotes , Medo/psicologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
17.
J Neurosci ; 32(45): 15802-14, 2012 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-23136419

RESUMO

Fear is an emotional response to danger that is highly conserved throughout evolution because it is critical for survival. Accordingly, episodic memory for fearful locations is widely studied using contextual fear conditioning, a hippocampus-dependent task (Kim and Fanselow, 1992; Phillips and LeDoux, 1992). The hippocampus has been implicated in episodic emotional memory and is thought to integrate emotional stimuli within a spatial framework. Physiological evidence supporting the role of the hippocampus in contextual fear indicates that pyramidal cells in this region, which fire in specific locations as an animal moves through an environment, shift their preferred firing locations shortly after the presentation of an aversive stimulus (Moita et al., 2004). However, the long-term physiological mechanisms through which emotional memories are encoded by the hippocampus are unknown. Here we show that during and directly after a fearful experience, new hippocampal representations are established and persist in the long term. We recorded from the same place cells in mouse hippocampal area CA1 over several days during predator odor contextual fear conditioning and found that a subset of cells changed their preferred firing locations in response to the fearful stimulus. Furthermore, the newly formed representations of the fearful context stabilized in the long term. Our results demonstrate that place cells respond to the presence of an aversive stimulus, modify their firing patterns during emotional learning, and stabilize a long-term spatial representation in response to a fearful encounter. The persistent nature of these representations may contribute to the enduring quality of emotional memories.


Assuntos
Região CA1 Hipocampal/fisiologia , Condicionamento Psicológico/fisiologia , Emoções/fisiologia , Medo/fisiologia , Neurônios/fisiologia , Animais , Masculino , Camundongos , Odorantes
18.
J Am Chem Soc ; 133(51): 20684-7, 2011 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-22129213

RESUMO

To increase the biochemical efficiency of biosynthetic systems, metabolic engineers have explored different approaches for organizing enzymes, including the generation of unnatural fusion proteins. Previous work aimed at improving the biosynthesis of resveratrol, a stilbene associated a range of health-promoting activities, in yeast used an unnatural engineered fusion protein of Arabidopsis thaliana (thale cress) 4-coumaroyl-CoA ligase (At4CL1) and Vitis vinifera (grape) stilbene synthase (VvSTS) to increase resveratrol levels 15-fold relative to yeast expressing the individual enzymes. Here we present the crystallographic and biochemical analysis of the 4CL::STS fusion protein. Determination of the X-ray crystal structure of 4CL::STS provides the first molecular view of an artificial didomain adenylation/ketosynthase fusion protein. Comparison of the steady-state kinetic properties of At4CL1, VvSTS, and 4CL::STS demonstrates that the fusion protein improves catalytic efficiency of either reaction less than 3-fold. Structural and kinetic analysis suggests that colocalization of the two enzyme active sites within 70 Å of each other provides the basis for enhanced in vivo synthesis of resveratrol.


Assuntos
Acil Coenzima A/química , Aciltransferases/química , Arabidopsis/enzimologia , Proteínas Recombinantes de Fusão/química , Vitis/enzimologia , Acil Coenzima A/genética , Acil Coenzima A/metabolismo , Aciltransferases/genética , Aciltransferases/metabolismo , Arabidopsis/química , Arabidopsis/genética , Cristalografia por Raios X , Expressão Gênica , Cinética , Modelos Moleculares , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/genética , Vitis/química , Vitis/genética
19.
Nanotechnology ; 19(35): 355708, 2008 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-21828862

RESUMO

Although butterfly wings and water strider legs have an anti-wetting property, their working conditions are quite different. Water striders, for example, live in a wet environment and their legs need to support their weight and bear the high pressure during motion. In this work, we have focused on the importance of the surface geometrical structures in determining their performance. We have applied an atomic layer deposition technique to coat the surfaces of both butterfly wings and water strider legs with a uniform 30 nm thick hydrophilic Al(2)O(3) film. By keeping the surface material the same, we have studied the effect of different surface roughness/structure on their hydrophobic property. After the surface coating, the butterfly wings changed to become hydrophilic, while the water strider legs still remained super-hydrophobic. We suggest that the super-hydrophobic property of the water strider is due to the special shape of the long inclining spindly cone-shaped setae at the surface. The roughness in the surface can enhance the natural tendency to be hydrophobic or hydrophilic, while the roughness in the normal direction of the surface is favorable for forming a composite interface.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...