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1.
EMBO J ; 43(9): 1740-1769, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38565949

RESUMEN

The Hippo pathway effectors Yes-associated protein 1 (YAP) and its homolog TAZ are transcriptional coactivators that control gene expression by binding to TEA domain (TEAD) family transcription factors. The YAP/TAZ-TEAD complex is a key regulator of cancer-specific transcriptional programs, which promote tumor progression in diverse types of cancer, including breast cancer. Despite intensive efforts, the YAP/TAZ-TEAD complex in cancer has remained largely undruggable due to an incomplete mechanistic understanding. Here, we report that nuclear phosphoinositides function as cofactors that mediate the binding of YAP/TAZ to TEADs. The enzymatic products of phosphoinositide kinases PIPKIα and IPMK, including phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and phosphatidylinositol 3,4,5-trisphosphate (P(I3,4,5)P3), bridge the binding of YAP/TAZ to TEAD. Inhibiting these kinases or the association of YAP/TAZ with PI(4,5)P2 and PI(3,4,5)P3 attenuates YAP/TAZ interaction with the TEADs, the expression of YAP/TAZ target genes, and breast cancer cell motility. Although we could not conclusively exclude the possibility that other enzymatic products of IPMK such as inositol phosphates play a role in the mechanism, our results point to a previously unrecognized role of nuclear phosphoinositide signaling in control of YAP/TAZ activity and implicate this pathway as a potential therapeutic target in YAP/TAZ-driven breast cancer.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Neoplasias de la Mama , Transducción de Señal , Transactivadores , Factores de Transcripción , Proteínas Señalizadoras YAP , Humanos , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Proteínas Señalizadoras YAP/metabolismo , Proteínas Señalizadoras YAP/genética , Femenino , Transactivadores/metabolismo , Transactivadores/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ/metabolismo , Línea Celular Tumoral , Fosfatos de Fosfatidilinositol/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositoles/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Núcleo Celular/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética
2.
Chembiochem ; : e202300853, 2024 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-38705850

RESUMEN

In this study, we present the probe SATE-G3P-N3 as a novel tool for metabolic labeling of glycerolipids (GLs) to investigate lipid metabolism in yeast cells. By introducing a clickable azide handle onto the glycerol backbone, this probe enables general labeling of glycerolipids. Additionally, this probe contains a caged phosphate moiety at the glycerol sn-3 position to not only facilitate probe uptake by masking negative charge but also to bypass the phosphorylation step crucial for initiating phospholipid synthesis, thereby enhancing phospholipid labeling. The metabolic labeling activity of the probe was thoroughly assessed through cellular fluorescence microscopy, mass spectrometry (MS), and thin-layer chromatography (TLC) experiments. Fluorescence microscopy analysis demonstrated successful incorporation of the probe into yeast cells, with labeling predominantly localized at the plasma membrane. LCMS analysis confirmed metabolic labeling of various phospholipid species (PC, PS, PA, PI, and PG) and neutral lipids (MAG, DAG, and TAG), and GL labeling was corroborated by TLC. These results showcased the potential of the SATE-G3P-N3 probe in studying GL metabolism, offering a versatile and valuable approach to explore the intricate dynamics of lipids in yeast cells.

3.
BMC Psychiatry ; 24(1): 390, 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38783227

RESUMEN

BACKGROUND: Cognitive Behaviour Therapy (CBT) is one of the most successful therapeutic approaches for treating anxiety and depression. Clinical trials show that for some clients, internet-based CBT (eCBT) is as effective as other CBT delivery modes. However, the fidelity of these effects may be weakened in real-world settings where clients and providers have the freedom to choose a CBT delivery mode and switch treatments at any time. The purpose of this study is to measure the CBT attendance rate and identify client-level characteristics associated with delivery mode selection and having reliable and clinically significant improvement (RCSI) of treatment in each delivery mode in a real-world CBT outpatient program. METHODS: This is a retrospective cohort analysis of electronic medical records collected between May 1, 2019, and March 31, 2022, at Ontario Shores Centre for Mental Health Sciences. Regression models were used to investigate the impact of individual client characteristics on participation and achieving RCSI of different CBT delivery modes. RESULTS: Our data show a high attendance rate for two and more CBT sessions across all modalities (98% of electronic, 94% of group, 100% of individual, and 99% of mixed CBT). Individuals were more likely to enter mixed and group CBT modality if they were younger, reported being employed, and reported higher depression severity at the baseline. Among the four modalities of CBT delivery, group CBT clients were least likely to have RCSI. Of those who started sessions, clients were significantly more likely to experience RCSI on the Patient Health Questionnaire (PHQ)-9 and the Generalized Anxiety Disorder (GAD)-7 if they were employed, reported more severe symptoms at baseline, and were living in the most deprived neighborhoods. CONCLUSIONS: This study will contribute to the body of knowledge about the implementation and treatment planning of different CBT delivery modes in real-world settings. With the changing clinical environment, it is possible to advocate for the adoption of the eCBT intervention to improve therapy practices and achieve better treatment success. The findings can help guide future CBT program planning based on client socio-demographic characteristics, allowing the optimal therapy type to be targeted to the right client at the right time.


Asunto(s)
Trastornos de Ansiedad , Terapia Cognitivo-Conductual , Humanos , Terapia Cognitivo-Conductual/métodos , Femenino , Masculino , Adulto , Estudios Retrospectivos , Persona de Mediana Edad , Trastornos de Ansiedad/terapia , Trastorno Depresivo/terapia , Intervención basada en la Internet , Adulto Joven , Ontario
4.
Can J Psychiatry ; : 7067437241261928, 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39051555

RESUMEN

BACKGROUND: Schizophrenia spectrum disorders (SSDs) are a group of psychiatric disorders characterized by positive and negative symptoms as well as cognitive impairment that can significantly affect daily functioning. METHOD: We reviewed evidence-based strategies for improving cognitive function in patients with SSDs, focusing on the Canadian landscape. RESULTS: Although antipsychotic medications can address the positive symptoms of SSDs, cognitive symptoms often persist, causing functional impairment and reduced quality of life. Moreover, cognitive function in patients with SSDs is infrequently assessed in clinical practice, and evidence-based recommendations for addressing cognitive impairment in people living with schizophrenia are limited. While cognitive remediation (CR) can improve several domains of cognitive function, most individuals with SSDs are currently not offered such an intervention. While the development of implementation strategies for CR is underway, available and emerging pharmacological treatments may help overcome the limited capacity for psychosocial approaches. Furthermore, combining pharmacological with non-pharmacological interventions may improve outcomes compared to pharmacotherapy or CR alone. CONCLUSION: This review highlights the challenges and discusses the potential solutions related to the assessment and management of cognitive impairment to help mental health-care practitioners better manage cognitive impairment and improve daily functioning in individuals with SSDs.


Improving Thinking Skills in People With Schizophrenia: A Focus on CanadaPlain Language SummarySchizophrenia spectrum disorders (SSDs) are mental health conditions that can cause a mix of symptoms making everyday life difficult for people. For example, some people might experience positive symptoms like seeing and hearing things that are not there, having false believes, or feeling suspicious. Others might experience negative symptoms like isolating from social interactions, having trouble showing emotion, or finding it hard to connect with others. Finally, they might also have trouble with thinking skills, like paying attention, planning and organizing, remembering things, or understanding social cues. While some medicines can help with some of the symptoms, they often do not help with improving thinking skills. In addition, these thinking problems are not checked often enough in patients with SSDs. In fact, there are not many proven ways to help with these issues. One method that can help with thinking skills is called cognitive remediation (CR), but it is not offered to most people with SSDs. There are ongoing efforts to make CR more available. It is also possible that CR may be combined with new medicines to make it work better than using just one treatment. This article looks at ways to improve thinking skills in people with SSDs, with a focus on what is happening in Canada. We present the challenges and possible solutions for checking and managing thinking problems, to help health-care workers better care for people with SSDs.

5.
Chembiochem ; 24(2): e202200436, 2023 01 17.
Artículo en Inglés | MEDLINE | ID: mdl-36164720

RESUMEN

Liposomes are highly effective nanocarriers for encapsulating and delivering a wide range of therapeutic cargo. While advancements in liposome design have improved several pharmacological characteristics, an important area that would benefit from further progress involves cellular targeting and entry. In this concept article, we will focus on recent progress utilizing strategies including reversible covalent bonding and caging groups to activate liposomal cell entry. These approaches take advantage of advancements that have been made in complementary fields including molecular sensing and chemical biology and direct this technology toward controlling liposome cell delivery properties. The decoration of liposomes with groups including boronic acids and cyclic disulfides is presented as a means for driving delivery through reaction with functional groups on cell surfaces. Additionally, caging groups can be exploited to activate cell delivery only upon encountering a target stimulus. These approaches provide promising new avenues for controlling cell delivery in the development of next-generation liposomal therapeutic nanocarriers.


Asunto(s)
Sistemas de Liberación de Medicamentos , Liposomas , Liposomas/química , Portadores de Fármacos/química , Membrana Celular , Disulfuros
6.
Acc Chem Res ; 55(20): 2882-2891, 2022 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-36174148

RESUMEN

The ability to exert control over lipid properties, including structure, charge, function, and self-assembly characteristics is a powerful tool that can be implemented to achieve a wide range of biomedical applications. Examples in this arena include the development of caged lipids for controlled activation of signaling properties, metabolic labeling strategies for tracking lipid biosynthesis, lipid activity probes for identifying cognate binding partners, approaches for in situ membrane assembly, and liposome triggered release strategies. In this Account, we describe recent advancements in the latter area entailing the development of stimuli-responsive liposomes through programmable changes to lipid self-assembly properties, which can be harnessed to drive the release of encapsulated contents toward applications including drug delivery. We will focus on an emerging paradigm involving liposomal platforms that are sensitized toward chemical agents ranging from metal cations to small organic molecules that exhibit dysregulation in disease states. This has been achieved by developing synthetic lipid switches that are designed to undergo programmed conformational changes upon the recognition of specific target analytes. These structural alterations are leveraged to perturb the packing of lipids within the membrane and thereby drive the release of encapsulated contents.We provide an overview of the inspiration, design, and characterization of liposomes that selectively respond to wide-ranging target analytes. This series of studies began with the development of calcium-responsive liposomes utilizing a lipid switch inspired by sensors including indo-1. Following this successful demonstration, we next showed that the selectivity of the lipid switch could be altered among different metal cations by producing a liposomal platform for which release is induced through zinc binding. Our next goal was to develop metabolite-responsive liposomes in which switching is driven by molecular recognition events involving phosphorylated small molecules. In this work, screening of lipid switches designed to interact with phosphorylated metabolites led to the identification of liposomal formulations that selectivity release contents in the presence of adenosine triphosphate (ATP). Finally, we were able to modulate the metabolite selectivity by rationally designing a modified lipid switch structure that is activated through complexation of inositol-(1,4,5)-trisphosphate (IP3). These projects show the progression of our approaches for liposome release triggered by molecular recognition principles, building from ion-responsive lipid switches to structures that are activated by small molecules. These "smart" liposomal platforms provide an important addition to the toolbox for controlled cargo release since they respond to ions or small molecules that are commonly overproduced by diseased cells.


Asunto(s)
Calcio , Liposomas , Adenosina Trifosfato , Calcio/química , Inositol , Lípidos/química , Liposomas/química , Zinc
7.
Chemistry ; 29(38): e202300417, 2023 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-37085958

RESUMEN

We report the use of clickable monoacylglycerol (MAG) analogs as probes for the labeling of glycerolipids during lipid metabolism. Incorporation of azide tags onto the glycerol region was pursued to develop probes that would label glycerolipids, in which the click tag would not be removed through processes including acyl chain and headgroup remodeling. Analysis of clickable MAG probes containing acyl chains of different length resulted in widely variable cell imaging and cytotoxicity profiles. Based on these results, we focused on a probe bearing a short acyl chain (C4 -MAG-N3 ) that was found to infiltrate natural lipid biosynthetic pathways to produce click-tagged versions of both neutral and phospholipid products. Alternatively, strategic blocking of the glycerol sn-3 position in probe C4 -MEG-N3 served to deactivate phospholipid tagging and focus labeling on neutral lipids. This work shows that lipid metabolic labeling profiles can be tuned based on probe structures and provides valuable tools for evaluating alterations to lipid metabolism in cells.


Asunto(s)
Glicerol , Fosfolípidos , Metabolismo de los Lípidos
8.
Org Biomol Chem ; 21(5): 955-959, 2023 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-36622111

RESUMEN

In this work, we report triggered content release from liposomes brought about by copper chelation to a synthetic lipid switch containing a picolinamide headgroup. Fluorescence-based dye-leakage assays showcase release of carboxyfluorescein dye cargo upon copper treatment and control of liposomal release based on copper abundance. Our results additionally show that this platform is selective for copper and is accompanied by significant changes to liposome properties upon treatment with this ion.


Asunto(s)
Cobre , Liposomas , Ácidos Picolínicos , Colorantes Fluorescentes , Lípidos
9.
Bioorg Med Chem ; 87: 117301, 2023 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-37150117

RESUMEN

In this work, we report the design, synthesis, and application of a bis-pyrene phospholipid probe for detection of phospholipase A2 action through changes in pyrene monomer and excimer fluorescence intensities. Continuous fluorometric assays enabled detection of the activities of multiple PLA2 enzymes as well as the decrease in catalysis by PLA2 from honey bee venom caused by the inhibitor p-bromo phenacylbromide. Thin-layer chromatography and mass spectrometry analysis were also used to validate probe hydrolysis by PLA2. Mass spectrometry data also supported cleavage of the probe by phospholipase C and D enzymes, although changes in fluorescence were not observed in these cases. Nevertheless, the bis-pyrene phospholipid probe developed in this work is effective for detection of PLA2 enzyme activity through an assay that enables screening for inhibitor development.


Asunto(s)
Fosfolipasas , Fosfolípidos , Hidrólisis , Fosfolipasas/análisis , Fosfolipasas A2/química , Pirenos
10.
Psychopathology ; 56(6): 462-472, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37094551

RESUMEN

INTRODUCTION: Individuals with schizotypy can experience a number of cognitive biases that may increase their risk in developing schizophrenia-spectrum psychopathology. However, cognitive biases are also present in mood and anxiety disorders, and it is currently unclear which biases are specific to schizotypy and which may be a result of comorbid depression and/or anxiety. METHODS: 462 participants completed measures of depression, anxiety, cognitive biases, cognitive schemas, and schizotypy. Correlation analyses were conducted to examine the relationship between these constructs. Three hierarchical regression analyses were conducted to examine if schizotypy, depression, and anxiety explained a statistically significant amount of variance in cognitive biases after controlling for depression and anxiety, schizotypy and anxiety, and schizotypy and depression, respectively. Moderated regression analyses were also conducted to investigate the moderating role of biological sex and ethnicity in the association between cognitive biases and schizotypy. RESULTS: Self-referential processing, belief inflexibility, and attention for threat were associated with schizotypy. The belief inflexibility bias and social cognition problems were specifically associated with schizotypy after controlling for depression and anxiety and were not directly associated with either depression or anxiety. These associations were not moderated by biological sex or ethnicity. CONCLUSION: The belief inflexibility bias may be an important cognitive bias underlying schizotypal personality, and further research will be important to determine whether this bias is also associated with an increased likelihood of transitioning to psychosis.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Trastorno de la Personalidad Esquizotípica , Humanos , Trastorno de la Personalidad Esquizotípica/complicaciones , Trastorno de la Personalidad Esquizotípica/psicología , Trastornos Psicóticos/psicología , Ansiedad/complicaciones , Ansiedad/psicología , Esquizofrenia/complicaciones , Cognición
11.
J Am Chem Soc ; 144(8): 3746-3756, 2022 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-35171601

RESUMEN

Liposomal delivery vehicles can dramatically enhance drug transport. However, their clinical application requires enhanced control over content release at diseased sites. For this reason, triggered release strategies have been explored, although a limited toolbox of stimuli has thus far been developed. Here, we report a novel strategy for stimuli-responsive liposomes that release encapsulated contents in the presence of phosphorylated small molecules. Our formulation efforts culminated in selective cargo release driven by ATP, a universal energy source that is upregulated in diseases such as cancer. Specifically, we developed lipid switches 1a-b bearing two ZnDPA units designed to undergo substantial conformational changes upon ATP binding, thereby disrupting membrane packing and triggering the release of encapsulated contents. Dye leakage assays using the hydrophobic dye Nile red validated that ATP-driven release was selective over 11 similar phosphorylated metabolites, and release of the hydrophilic dye calcein was also achieved. Multiple alternative lipid switch structures were synthesized and studied (1c-d and 2), which provided insights into the structural features that render 1a-b selective toward ATP-driven release. Importantly, analysis of cellular delivery using fluorescence microscopy in conjunction with pharmacological ATP manipulation showed that liposome delivery was specific, as it increased upon intracellular ATP accumulation, and was inhibited by ATP downregulation. Our new approach shows strong prospects for enhancing the selectivity of release and payload delivery to diseased cells driven by metabolites such as ATP, providing an exciting new paradigm for controlled release.


Asunto(s)
Lípidos , Liposomas , Adenosina Trifosfato , Lípidos/química , Liposomas/química
12.
Chembiochem ; 23(21): e202200402, 2022 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-36044591

RESUMEN

Liposomes are effective therapeutic nanocarriers due to their ability to encapsulate and enhance the pharmacokinetic properties of a wide range of drugs and diagnostic agents. A primary area in which improvement is needed for liposomal drug delivery is to maximize the delivery of these nanocarriers to cells. Cell membrane glycans provide exciting targets for liposomal delivery since they are often densely clustered on cell membranes and glycan overabundance and aberrant glycosylation patterns are a common feature of diseased cells. Herein, we report a liposome platform incorporating bis-boronic acid lipids (BBALs) to increase valency in order to achieve selective saccharide sensing and enhance cell surface recognition based on carbohydrate binding interactions. In order to vary properties, multiple BBALs (1 a-d) with variable linkers in between the binding units were designed and synthesized. Fluorescence-based microplate screening of carbohydrate binding showed that these compounds exhibit varying binding properties depending on their structures. Additionally, fluorescence microscopy experiments indicated enhancements in cellular association when BBALs were incorporated within liposomes. These results demonstrate that multivalent BBALs serve as an exciting glycan binding liposome system for targeted delivery.


Asunto(s)
Ácidos Borónicos , Liposomas , Liposomas/química , Ácidos Borónicos/química , Carbohidratos , Membrana Celular , Polisacáridos , Sistemas de Liberación de Medicamentos/métodos
13.
Chemistry ; 28(45): e202201164, 2022 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-35699671

RESUMEN

Liposomes are effective therapeutic delivery nanocarriers due to their ability to encapsulate and enhance the pharmacokinetic properties of a wide range of therapeutics. Two primary areas in which improvement is needed for liposomal drug delivery is to enhance the ability to infiltrate cells and to facilitate derivatization of the liposome surface. Herein, we report a liposome platform incorporating a cyclic disulfide lipid (CDL) for the dual purpose of enhancing cell entry and functionalizing the liposome membrane through thiol-disulfide exchange. In order to accomplish this, CDL-1 and CDL-2, composed of lipoic acid (LA) or asparagusic acid (AA) appended to a lipid scaffold, were designed and synthesized. A fluorescence-based microplate immobilization assay was implemented to show that these compounds enable convenient membrane decoration through reaction with thiol-functionalized small molecules. Additionally, fluorescence microscopy experiments indicated dramatic enhancements in cellular delivery when CDLs were incorporated within liposomes. These results demonstrate that multifunctional CDLs serve as an exciting liposome system for surface decoration and enhanced cellular delivery.


Asunto(s)
Sistemas de Liberación de Medicamentos , Liposomas , Disulfuros , Sistemas de Liberación de Medicamentos/métodos , Lípidos , Liposomas/metabolismo , Compuestos de Sulfhidrilo
14.
Chemistry ; 28(46): e202201057, 2022 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-35639353

RESUMEN

We report boronate-caged guanidine-lipid 1 that activates liposomes for cellular delivery only upon uncaging of this compound by reactive oxygen species (ROS) to produce cationic lipid products. These liposomes are designed to mimic the exceptional cell delivery properties of cell-penetrating peptides (CPPs), while the inclusion of the boronate cage is designed to enhance selectivity such that cell entry will only be activated in the presence of ROS. Boronate uncaging by hydrogen peroxide was verified by mass spectrometry and zeta potential (ZP) measurements. A microplate-based fluorescence assay was developed to study the ROS-mediated vesicle interactions between 1-liposomes and anionic membranes, which were further elucidated via dynamic light scattering (DLS) analysis. Cellular delivery studies utilizing fluorescence microscopy demonstrated significant enhancements in cellular delivery only when 1-liposomes were incubated with hydrogen peroxide. Our results showcase that lipid 1 exhibits strong potential as an ROS-responsive liposomal platform for targeted drug delivery applications.


Asunto(s)
Peróxido de Hidrógeno , Liposomas , Guanidina , Lípidos/química , Liposomas/química , Especies Reactivas de Oxígeno/metabolismo
15.
Bioconjug Chem ; 32(12): 2485-2496, 2021 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-34870414

RESUMEN

Liposomes are effective nanocarriers due to their ability to encapsulate and deliver a wide variety of therapeutics. However, therapeutic potential would be improved by enhanced control over the release of drug cargo. Zinc ions provide exciting new targets for stimuli-responsive lipid design due to their overly abundant concentrations associated with diseased cells. Herein, we report zinc-triggered release of liposomal contents exploiting synthetic lipid switches designed to undergo conformational changes in the presence of this ion. Initially, Nile red leakage assays were conducted that validated successful dose-dependent triggering of release using zinc-responsive lipids (ZRLs). In addition, dynamic light scattering and confocal microscopy experiments showed that zinc treatment led to morphological changes in lipid nanoparticles only when ZRLs were present in formulations. Next, zinc-binding experiments conducted in a solution (NMR, MS) or membrane (zeta potential) context confirmed ZRL-Zn complexation. Finally, polar cargo release from liposomes was achieved. The results from these wide-ranging experiments using four different compounds indicated that zinc-responsive properties varied based on ZRL structure, providing insights into the structural requirements for activity. This work has established zinc-responsive liposomal platforms toward the development of clinical triggered release formulations.


Asunto(s)
Liposomas , Nanopartículas
16.
J Chem Phys ; 154(3): 034703, 2021 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-33499640

RESUMEN

We report a comprehensive experimental and theoretical study of the lower-wavenumber vibrational modes in the surface-enhanced hyper-Raman scattering (SEHRS) of Rhodamine 6G (R6G) and its isotopologue R6G-d4. Measurements acquired on-resonance with two different electronic states, S1 and S2, are compared to the time-dependent density functional theory computations of the resonance hyper-Raman spectra and electrodynamics-quantum mechanical computations of the SEHRS spectra on-resonance with S1 and S2. After accounting for surface orientation, we find excellent agreement between experiment and theory for both R6G and its isotopologue. We then present a detailed analysis of the complex vibronic coupling effects in R6G and the importance of surface orientation for characterizing the system. This combination of theory and experiment allows, for the first time, an unambiguous assignment of lower-wavenumber vibrational modes of R6G and its isotopologue R6G-d4.

17.
Pers Individ Dif ; 175: 110704, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33531727

RESUMEN

BACKGROUND: The COVID-19 pandemic has produced a worldwide mental health crisis. Conspiracy beliefs regarding the origin of COVID-19 are prevalent, however, mental health consequences and factors associated with the likelihood of endorsing COVID-19 conspiracy theories have not yet been examined. The current study examined predictors and mental health consequences of conspiracy beliefs. METHODS: Participants in Canada and the United States were surveyed via Amazon Mechanical Turk in April 2020 (N = 797), approximately one month after the WHO declared COVID-19 a pandemic, and again in May 2020 (N = 395). RESULTS: Approximately half of the sample (49.7%) believed at least one conspiracy theory. Greater Covid-19 conspiracy beliefs were associated with more anxiety at follow up but not quality of life. Religiosity/spirituality, not knowing someone at high-risk for COVID-19, and non-white ethnicity were associated with greater conspiracy beliefs. Lower positive other-schemas were associated with greater conspiracy beliefs, only at low and moderate levels of positive self-schemas. CONCLUSIONS: There is substantial conspiracy belief endorsement during the COVID-19 pandemic and conspiracy beliefs are associated with anxiety, but not quality of life. Positive self-schemas protect against believing conspiracy theories and interventions to increase positive self-schemas may be effective to reduce the negative effects of conspiracy beliefs.

18.
Clin Psychol Psychother ; 28(6): 1379-1390, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34734452

RESUMEN

Cognitive-behavioural models of health anxiety propose a positive association between information seeking and health anxiety; however, it is unclear the extent to which cognitive mechanisms may mediate this relationship. Catastrophic cognitions are one type of cognition that may mediate this relationship, and the COVID-19 pandemic has presented an opportunity to examine these relationships within the context of a global health catastrophe. The current study investigated both cross-sectional (N = 797) and longitudinal (n = 395) relationships between information seeking, health anxiety and catastrophizing during the pandemic. Data were collected using Amazon Mechanical Turk during April and May 2020. Information seeking and health anxiety were positively associated both cross-sectionally and longitudinally (rs = .25-.29). Catastrophic cognitions significantly mediated the relationship between information seeking and health anxiety both cross-sectionally and longitudinally. Developing effective methods of reducing information seeking and catastrophizing may serve to reduce health anxiety during global health crises such as the current pandemic.


Asunto(s)
COVID-19 , Pandemias , Ansiedad/epidemiología , Cognición , Estudios Transversales , Humanos , Conducta en la Búsqueda de Información , SARS-CoV-2
19.
Bioconjug Chem ; 31(9): 2220-2230, 2020 09 16.
Artículo en Inglés | MEDLINE | ID: mdl-32808755

RESUMEN

Liposomes have proven to be effective nanocarriers due to their ability to encapsulate and deliver a wide variety of therapeutic cargo. A key goal of liposome research is to enhance control over content release at diseased sites. Though a number of stimuli have been explored for triggering liposomal release, reactive oxygen species (ROS), which have received significantly less attention, provide excellent targets due to their key roles in biology and overabundance in diseased cells. Here, we report a ROS-responsive liposome platform through the inclusion of lipid 1 bearing a boronate ester headgroup and a quinone-methide (QM) generating self-immolative linker attached onto a dioleoylphosphatidylethanolamine (DOPE) lipid scaffold. Fluorescence-based dye release assays validated that this system enables release of both hydrophobic and hydrophilic contents upon hydrogen peroxide (H2O2) addition. Details of the release process were carefully studied, and data showed that oxidative removal of the boronate headgroup is sufficient to result in hydrophobic content release, while production of DOPE is needed for hydrophilic cargo leakage. These results showcase that lipid 1 can serve as a promising ROS-responsive liposomal delivery platform for controlled release.


Asunto(s)
Compuestos de Boro/química , Preparaciones de Acción Retardada/química , Liposomas/química , Fosfatidiletanolaminas/química , Especies Reactivas de Oxígeno/química , Colorantes Fluorescentes/administración & dosificación , Indolquinonas/química
20.
Chemistry ; 26(39): 8597-8607, 2020 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-32301193

RESUMEN

Liposomes are effective nanocarriers due to their ability to deliver encapsulated drugs to diseased cells. Nevertheless, liposome delivery would be improved by enhancing the ability to control the release of contents at the target site. While various stimuli have been explored for triggering liposome release, enzymes provide excellent targets due to their common overexpression in diseased cells. We present a general approach to enzyme-responsive liposomes exploiting targets that are commonly aberrant in disease, including esterases, phosphatases, and ß-galactosidases. Responsive lipids correlating with each enzyme family were designed and synthesized bearing an enzyme substrate moiety attached via a self-immolating linker to a non-bilayer lipid scaffold, such that enzymatic hydrolysis triggers lipid decomposition to disrupt membrane integrity and release contents. Liposome dye leakage assays demonstrated that each enzyme-responsive liposome yielded significant content release upon enzymatic treatment compared to minimal release in controls. Results also showed that fine-tuning liposome composition was critical for controlling release. DLS analysis showed particle size increases in the cases of esterase- and ß-galactosidase-responsive lipids, supporting alterations to membrane properties. These results showcase an effective modular strategy that can be tailored to target different enzymes, providing a promising new avenue for advancing liposomal drug delivery.


Asunto(s)
Lípidos/química , Liposomas/química , beta-Galactosidasa/química , Sistemas de Liberación de Medicamentos/métodos , Liposomas/metabolismo , Tamaño de la Partícula
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