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1.
Biopharm Drug Dispos ; 45(3): 117-126, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38646776

RESUMO

This study aimed to control the oral absorption of cyclosporine A (CsA) with the use of a mucosal drug delivery system (mDDS). Mucopenetrating nanocarriers (MP/NCs) and mucoadhesive nanocarriers (MA/NCs) were prepared by flash nanoprecipitation employing polystyrene-block-poly(ethylene glycol) and polystyrene-block-poly(N,N-dimethyl aminoethyl methacrylate), respectively. Their particle distribution in the rat gastrointestinal tract were visualized by fluorescent imaging. Plasma concentrations were monitored after oral administration of CsA-loaded MP/NCs (MP/CsA) and MA/NCs (MA/CsA) to rats. MP/NCs and MA/NCs had a particle size below 200 nm and ζ-potentials of 4 and 40 mV, respectively. The results from in vitro experiments demonstrated mucopenetration of MP/NCs and mucoadhesion of MA/NCs. Confocal laser scanning microscopic images showed diffusion of MP/NCs in the gastrointestinal mucus towards epithelial cells and localization of MA/NCs on the surface of the gastrointestinal mucus layer. In a pH 6.8 solution, rapid and sustained release of CsA were observed for MP/CsA and MA/CsA, respectively. After oral dosing (10 mg-CsA/kg) to rats, amorphous CsA powder exhibited a time to maximum plasma concentration (Tmax) of 3.4 h, maximum plasma concentration (Cmax) of 0.12 µg/mL, and bioavailability of 0.7%. Compared with amorphous CsA powder, MP/CsA shortened Tmax by 1.1 to 2.3 h and increased the bioavailability by 43-fold to 30.1%, while MA/CsA prolonged Tmax by 3.4 to 6.8 h with Cmax and bioavailability of 0.65 µg/mL and 11.7%, respectively. These pharmacokinetic behaviors would be explained by their diffusion and release properties modulated by polymeric surface modification. The mDDS approach is a promising strategy for the pharmacokinetic control of orally administered CsA.


Assuntos
Ciclosporina , Sistemas de Liberação de Medicamentos , Ratos Sprague-Dawley , Animais , Ciclosporina/farmacocinética , Ciclosporina/administração & dosagem , Masculino , Administração Oral , Ratos , Imunossupressores/farmacocinética , Imunossupressores/administração & dosagem , Imunossupressores/sangue , Portadores de Fármacos/química , Mucosa Intestinal/metabolismo , Nanopartículas/química , Disponibilidade Biológica , Tamanho da Partícula
2.
Comput Inform Nurs ; 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38270543

RESUMO

Keeping students engaged and motivated during online or class discussion may be challenging. Artificial intelligence has potential to facilitate active learning by enhancing student engagement, motivation, and learning outcomes. The purpose of this study was to develop, test usability of, and explore undergraduate nursing students' perceptions toward the Artificial Intelligence-Teaching Assistant System. The system was developed based on three main components: machine tutor intelligence, a graphical user interface, and a communication connector. They were included in the system to support contextual machine tutoring. A field-testing study design, a mixed-method approach, was utilized with questionnaires and focus group interview. Twenty-one undergraduate nursing students participated in this study, and they interacted with the system for 2 hours following the required activity checklist. The students completed the validated usability questionnaires and then participated in the focus group interview. Descriptive statistics were used to analyze quantitative data, and thematic analysis was used to analyze qualitative data from the focus group interviews. The results showed that the Artificial Intelligence-Teaching Assistant System was user-friendly. Four main themes emerged, namely, functionality, feasibility, artificial unintelligence, and suggested learning modality. However, Artificial Intelligence-Teaching Assistant System functions, user interface, and content can be improved before full implementation.

3.
Helminthologia ; 61(1): 76-84, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38659466

RESUMO

Pratylenchus coffeae, belonging to the root-lesion nematode group, is a highly prevalent and destructive plant-parasitic nematode that is able to infest a wide range of host plants. Although this species' devastating impacts on coffee plantations across the world are widely known on other host plants, its association with Ming aralia has never been reported. Our study characterized two popu lations of P. coffeae (associated with Ming aralia and coffee) and compared them with other popu lations from previous studies in Vietnam and other countries in the world. The identification of P. coffeae in our study was confirmed by the comprehensive analysis encompassing morphological examination, morphometric data, and molecular characterizations of the COI mtDNA and D2D3 of 28S rRNA regions. The cluster and MDS analyses revealed that the two populations of P. coffeae from Vietnam are closely related to those from Japan and Indonesia. The D2-D3 sequences of 28S rRNA and COI mtDNA regions exhibited high similarity among these populations, indicating a stable genetic profile. Our research contributes to a better understanding of the distribution and genetic characterizations of P. coffeae by offering new morphological and molecular insights into the presence of this nematode in Vietnam. Additionally, this nematode species was found to be associated with host plant's symptoms such as chlorotic leaves, stunted growth and root lesion in both hosts. Given the economic significance of both Ming aralia and coffee crops in Vietnam, as well as the damaging potential of P. coffeae, this study emphasizes the need of proactive nematode management measures to control this destructive pest.

4.
Phys Rev Lett ; 130(5): 051803, 2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36800477

RESUMO

The COHERENT Collaboration searched for scalar dark matter particles produced at the Spallation Neutron Source with masses between 1 and 220 MeV/c^{2} using a CsI[Na] scintillation detector sensitive to nuclear recoils above 9 keV_{nr}. No evidence for dark matter is found and we thus place limits on allowed parameter space. With this low-threshold detector, we are sensitive to coherent elastic scattering between dark matter and nuclei. The cross section for this process is orders of magnitude higher than for other processes historically used for accelerator-based direct-detection searches so that our small, 14.6 kg detector significantly improves on past constraints. At peak sensitivity, we reject the flux consistent with the cosmologically observed dark-matter concentration for all coupling constants α_{D}<0.64, assuming a scalar dark-matter particle. We also calculate the sensitivity of future COHERENT detectors to dark-matter signals which will ambitiously test multiple dark-matter spin scenarios.

5.
J Clin Nurs ; 32(17-18): 5562-5578, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36775886

RESUMO

AIM AND OBJECTIVE: As rising global prevalence of diabetes burdens an overstrained healthcare system, it would be prudent to employ primary prevention strategies. This review aims to detail characteristics of technology-enabled diabetes prevention programs (t-DPP) and the technology acceptance amongst prediabetic individuals. DESIGN: A scoping review. REVIEW METHODS: Summative and direct content analysis. DATA SOURCES: Seven electronic databases-PubMed, Cochrane, Embase, CINAHL, Scopus, PsycINFO and Web of Science-were searched from inception till 9 June 2022 for primary studies conducted on t-DPP. Initial search identified 2412 unique articles. Removal of duplicates and irrelevant articles resulted in 58 full text articles screened and 17 articles meeting the eligibility criteria. There was no limitation to study type or year of publication, but language was limited to English. RESULTS: Common t-DPP characteristics include physical activity (n = 17), diet control (n = 16), coaching (n = 12), social support (n = 9) and skills acquisition (n = 12). Technological acceptance of t-DPPs were generally positive as participants found them useful (n = 5) and easy to use (n = 4), with majority of the participants interested (n = 5) and engaging well with it (n = 13). However, personal-, design- and technological-level factors were found to negatively influence t-DPPs acceptance. CONCLUSION: This review reported a generally positive technological acceptance. The result encourages remote delivery of diabetes prevention programs, offering researchers a guide to t-DPP development. However, it also highlights the need for integration of behavioural change theories and socio-cultural considerations, with gaps in knowledge amongst men and young adults. IMPLICATIONS FOR NURSING: The success of t-DPP can reinforce clinical advice and sustain health behaviours advocated by nurses. Involvement of diabetes-trained nurses would enable continual risk assessment, monitoring and timely intervention to prevent diabetes and potential complications. REPORTING METHOD: PRISMA-ScR checklist.


Assuntos
Diabetes Mellitus Tipo 2 , Estado Pré-Diabético , Humanos , Masculino , Adulto Jovem , Diabetes Mellitus Tipo 2/prevenção & controle , Exercício Físico , Apoio Social , Tecnologia
6.
Phys Rev Lett ; 129(8): 081801, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-36053683

RESUMO

We measured the cross section of coherent elastic neutrino-nucleus scattering (CEvNS) using a CsI[Na] scintillating crystal in a high flux of neutrinos produced at the Spallation Neutron Source at Oak Ridge National Laboratory. New data collected before detector decommissioning have more than doubled the dataset since the first observation of CEvNS, achieved with this detector. Systematic uncertainties have also been reduced with an updated quenching model, allowing for improved precision. With these analysis improvements, the COHERENT Collaboration determined the cross section to be (165_{-25}^{+30})×10^{-40} cm^{2}, consistent with the standard model, giving the most precise measurement of CEvNS yet. The timing structure of the neutrino beam has been exploited to compare the CEvNS cross section from scattering of different neutrino flavors. This result places leading constraints on neutrino nonstandard interactions while testing lepton flavor universality and measures the weak mixing angle as sin^{2}θ_{W}=0.220_{-0.026}^{+0.028} at Q^{2}≈(50 MeV)^{2}.

7.
J Adv Nurs ; 78(4): 1154-1165, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35170786

RESUMO

AIM: To evaluate the effectiveness of a nurse-led smartphone-based self-management programme (NSSMP) on improving self-efficacy, promoting diabetes self-care, increasing health-related quality of life (HRQoL) and decreasing HbA1c, acute complications and unplanned medical consultation for people with poorly controlled type 2 diabetes compared with a nurse-led diabetic service (NDS). DESIGN: A two-arm randomized controlled trial with repeated measures was conducted. METHODS: Participants were recruited from June 2018 to September 2020. Eligible participants were assigned to either the intervention or control group randomly. Participants assigned to intervention group received the 6-month NSSMP, while those in the control group received existing NDS provided by the study hospital. Outcomes were measured at baseline, and at 3 and 6 months from baseline. RESULTS: A total of 114 participants were recruited. There were no significant interactions between group and time for all the outcomes except for blood glucose testing activities (F = 4.742, p = .015). Both groups had reduced HbA1c over 6 months. The intervention group had a lower HbA1c than the control group at follow-ups, but the differences were not statistically significant. None of the participants had acute diabetes complications at follow-up. Similarly, the differences in the number of unplanned medical consultation at 6-month follow-up between two groups were statistically insignificant. CONCLUSION: The NSSMP is as effective as existing NDS provided by the study hospital in improving most of the outcomes. NSSMP can liberate valuable time for nurses to provide care to critically ill patients and supports healthcare resource constraints in the current COVID-19 pandemic. IMPACT: The existing diabetes service is labour intensive as nurses are required to deliver education, follow-up telephone calls to trace blood sugar monitoring and provide therapeutic consultations and necessary referrals. The outbreak of COVID-19 pandemic has added further strain on the overworked professionals. NSSMP provides an alternative programme that is just as effective, to reduce nurses' workload by delegating them back to the individuals through self-management strategies. This enables nurses to increase contact time with patients, and individuals to take onus of their disease through increased self-efficacy, facilitated by technology. CLINICAL TRIAL: This study is registered under clinical registration number NCT03088475.


Assuntos
COVID-19 , Diabetes Mellitus Tipo 2 , Autogestão , Diabetes Mellitus Tipo 2/terapia , Humanos , Papel do Profissional de Enfermagem , Pandemias , Qualidade de Vida , SARS-CoV-2 , Smartphone
8.
Pharm Res ; 38(12): 2109-2118, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34904203

RESUMO

PURPOSE: This study was undertaken to develop novel mucoadhesive formulations of clofazimine (CFZ), a drug candidate for the treatment of cryptosporidiosis, with the aim of strategic delivery to the small intestine, the main site of the disease parasites. METHODS: CFZ-loaded nanoparticles (nCFZ) coated with non-biodegradable anionic polymer (nCFZ/A) and biodegradable anionic protein complex (nCFZ/dA) were prepared by Flash NanoPrecipitation (FNP) and evaluated for their physicochemical and biopharmaceutical properties. RESULTS: The mean diameters of nCFZ/A and nCFZ/dA were ca. 90 and 240 nm, respectively, and they showed narrow size distributions and negative ζ-potentials. Both formulations showed higher solubility of CFZ in aqueous solution than crystalline CFZ. Despite their improved dispersion behaviors, both formulations exhibited significantly lower diffusiveness than crystalline CFZ in a diffusion test using artificial mucus (AM). Quartz crystal microbalance analysis showed that both formulations clearly interacted with mucin, which appeared to be responsible for their reduced diffusiveness in AM. These results suggest the potent mucoadhesion of nCFZ/A and nCFZ/dA. After the oral administration of CFZ samples (10 mg-CFZ/kg) to rats, nCFZ/dA and nCFZ/A exhibited a prolongation in Tmax by 2 and >9 h, respectively, compared with crystalline CFZ. At 24 h after oral doses of nCFZ/A and nCFZ/dA with mucoadhesion, there were marked increases in the intestinal CFZ concentration (4-7 fold) compared with Lamprene®, a commercial CFZ product, indicating enhanced CFZ exposure in the small intestine. CONCLUSION: The use of FNP may produce mucoadhesive CFZ formulations with improved intestinal exposure, possibly offering enhanced anti-cryptosporidium therapy.


Assuntos
Clofazimina/administração & dosagem , Sistemas de Liberação de Fármacos por Nanopartículas/química , Administração Oral , Animais , Clofazimina/farmacocinética , Criptosporidiose/tratamento farmacológico , Liberação Controlada de Fármacos , Humanos , Absorção Intestinal , Mucosa Intestinal/metabolismo , Intestino Delgado/metabolismo , Masculino , Modelos Animais , Ratos , Solubilidade
9.
Neuroimage ; 200: 601-606, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31158477

RESUMO

PURPOSE: To achieve sufficient precision of R1 (=1/T1) maps of the fetal brain in utero to perform QUEnch-assiSTed (QUEST) MRI in which a significant anti-oxidant-induced reduction in R1 indicates oxidative stress. METHODS: C57BL/6 mouse fetuses in utero were gently and non-surgically isolated and secured using a homemade 3D printed clip. Using a commercial receive-only surface coil, brain maps of R1, an index sensitive to excessive and continuous free radical production, were collected using either a conventional Cartesian or a non-Cartesian (periodically rotated overlapping parallel lines with enhanced reconstruction) progressive saturation sequence. Data were normalized to the shortest TR time to remove bias. To assess oxidative stress, brain R1 maps were acquired on the lipopolysaccharide (LPS) model of preterm birth ±â€¯rosiglitazone (ROSI, which has anti-oxidant properties); phosphate buffered saline (PBS) controls ±â€¯ROSI were similarly studied. RESULTS: Sufficient quality R1 maps were generated by a combination of the 3D printed clip, surface coil detection, non-Cartesian sequence, and normalization scheme ensuring minimal fetal movement, good detection sensitivity, reduced motion artifacts, and minimal baseline variations, respectively. In the LPS group, the combined caudate-putamen and thalamus region R1 was reduced (p < 0.05) with ROSI treatment consistent with brain oxidative stress; no evidence for oxidative stress was found in the pons region. In the PBS control group, brain R1's did not change with ROSI treatment. CONCLUSION: The sensitivity and reproducibility of the combined approaches described herein enabled first-time demonstration of regional oxidative stress measurements of the fetal brain in utero using QUEST MRI.


Assuntos
Encéfalo/diagnóstico por imagem , Embrião de Mamíferos/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Estresse Oxidativo , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Embrião de Mamíferos/metabolismo , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Diagnóstico Pré-Natal
11.
J Adv Nurs ; 75(9): 1922-1932, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30786051

RESUMO

AIM: The aim of this study was to develop and examine the effectiveness of a 4-week Mobile Health (mHealth) programme using the smartphone app Care4Heart on awareness, knowledge, perceived stress, and a heart-related lifestyle among working population in Singapore. DESIGN: A quasi-experimental single group pretest and repeated post-test design. METHODS: A total of 160 nonhealth-related working adults were recruited from February 2016-April 2016. The Care4Heart app was installed on the participants' phones. Outcome measures, including the Heart Disease Fact Questionnaire-2, the Behavioral Risk Factor Surveillance System, and the Perceived Stress Scale were collected online at baseline, 4th week, and 6th month from baseline. RESULTS: Compared with the baseline, the participants had significantly higher total mean scores for awareness and knowledge of coronary heart disease (CHD) after study intervention at 4 weeks and 6 months from baseline. However, there were no significant differences in perceived stress levels and heart-related lifestyle behaviours before and after the intervention. CONCLUSIONS: The study contributed some evidence that the mHealth app helped to improve awareness and knowledge of CHD. IMPACT: Coronary heart disease remains one of the major causes of death and disability. It imposes a heavy financial burden on working adults. However, working adults were less able to identify the risk factors and adopt healthy lifestyles due to gaps in knowledge and awareness. This study demonstrated some effects of a mHealth programme in improving awareness and knowledge of CHD among the working population. mHealth provides a potential avenue for primary prevention of CHD.


Assuntos
Doença das Coronárias/prevenção & controle , Promoção da Saúde/métodos , Aplicativos Móveis , Telemedicina/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Singapura , Inquéritos e Questionários
12.
Nano Lett ; 18(8): 4791-4795, 2018 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-29989824

RESUMO

Because of its attractive cost and yield, hierarchical assembly, in which constituent structures of lower hierarchy share a majority of components, is an appealing approach to scale up DNA self-assembly. A few strategies have already been investigated to combine preformed DNA nanostructures. In this study, we present a new hierarchical assembly method based on four-way toehold-mediated strand displacement to facilitate the combination of preformed DNA structural units. Employing such a method, we have constructed a series of higher-order structures composed of 5, 7, 9, 11, 13, and 15 preformed units respectively.

13.
Mol Pharm ; 15(1): 216-225, 2018 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-29206046

RESUMO

Nanoprecipitation of active pharmaceutical ingredients (APIs) to form nanocarriers (NCs) is an attractive method of producing formulations with improved stability and biological efficacies. However, nanoprecipitation techniques have not been demonstrated for highly soluble peptide therapeutics. We here present a model and technique to encapsulate highly water-soluble biologic APIs by manipulating API salt forms. APIs are ion paired with hydrophobic counterions to produce new API salts that exhibit altered solubilities suitable for nanoprecipitation processing. The governing rules of ion pair identity and processing conditions required for successful encapsulation are experimentally determined and assessed with theoretical models. Successful NC formation for the antibiotic polymyxin B requires hydrophobicity of the ion pair acid to be greater than logP = 2 for strong acids and greater than logP = 8 for weak acids. Oleic acid with a logP = 8, and pKa = 5, appears to be a prime candidate as an ion pair agent since it is biocompatible and forms excellent ion pair complexes. NC formation from preformed, organic soluble ion pairs is compared to in situ ion pairs where NCs are made in a single precipitation step. NC properties, such as stability and release rates, can be tuned by varying ion pair molecular structure and ion pair-to-API molar ratios. For polymyxin B, NCs ≈ 100-200 nm in size, displaying API release rates over 3 days, were produced. This work demonstrates a new approach that enables the formation of nanoparticles from previously intractable compounds.


Assuntos
Antibacterianos/química , Portadores de Fármacos/química , Nanopartículas/química , Peptídeos/química , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Interações Hidrofóbicas e Hidrofílicas , Polimixina B/química , Solubilidade
14.
Mol Pharm ; 14(10): 3480-3488, 2017 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-28929769

RESUMO

Clofazimine, a lipophilic (log P = 7.66) riminophenazine antibiotic approved by the US Food and Drug Administration (FDA) with a good safety record, was recently identified as a lead hit for cryptosporidiosis through a high-throughput phenotypic screen. Cryptosporidiosis requires fast-acting treatment as it leads to severe symptoms which, if untreated, result in morbidity for infants and small children. Consequently, a fast-releasing oral formulation of clofazimine in a water-dispersible form for pediatric administration is highly desirable. In this work, clofazimine nanoparticles were prepared with three surface stabilizers, hypromellose acetate succinate (HPMCAS), lecithin, and zein, using the flash nanoprecipitation (FNP) process. Drug encapsulation efficiencies of over 92% were achieved. Lyophilization and spray-drying were applied and optimized to produce redispersible nanoparticle powders. The release kinetics of these clofazimine nanoparticle powders in biorelevant media were measured and compared with those of crystalline clofazimine and the currently marketed formulation Lamprene. Remarkably improved dissolution rates and clofazimine supersaturation levels up to 90 times equilibrium solubility were observed with all clofazimine nanoparticles tested. Differential scanning calorimetry indicated a reduction of crystallinity of clofazimine in nanoparticles. These results strongly suggest that the new clofazimine nanoparticles prepared with affordable materials in this low-cost nanoparticle formulation process can be used as viable cryptosporidiosis therapeutics.


Assuntos
Antiparasitários/farmacologia , Clofazimina/farmacologia , Criptosporidiose/tratamento farmacológico , Portadores de Fármacos/química , Composição de Medicamentos/métodos , Desenho de Fármacos , Antiparasitários/economia , Antiparasitários/uso terapêutico , Varredura Diferencial de Calorimetria , Química Farmacêutica , Clofazimina/economia , Clofazimina/uso terapêutico , Cristalização , Dessecação , Portadores de Fármacos/economia , Composição de Medicamentos/economia , Liberação Controlada de Fármacos , Excipientes/química , Liofilização , Nanopartículas/química , Nanopartículas/economia , Tamanho da Partícula , Solubilidade , Fatores de Tempo
15.
Health Qual Life Outcomes ; 15(1): 49, 2017 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-28288636

RESUMO

BACKGROUND: Coronary heart disease (CHD) is the most prevalent type of cardiac disease among adults worldwide, including those in Singapore. Most of its risk factors, such as smoking, physical inactivity and high blood pressure, are preventable. mHealth has improved in the last decade, showing promising results in chronic disease prevention and health promotion worldwide. Our aim was to develop and examine the effect of a 4-week Smartphone-Based Coronary Heart Disease Prevention (SBCHDP) programme in improving awareness and knowledge of CHD, perceived stress as well as cardiac-related lifestyle behaviours in the working population of Singapore. METHODS: The smartphone app "Care4Heart" was developed as the main component of the programme. App content was reviewed and validated by a panel of experts, including two cardiologists and two experienced cardiology-trained nurses. A pilot randomised controlled trial was conducted. Eighty working people were recruited and randomised to either the intervention group (n = 40) or the control group (n = 40). The intervention group underwent a 4-week SBCHDP programme, whereas the control group were offered health promotion websites only. The participants' CHD knowledge, perceived stress and behavioural risk factors were measured at baseline and on the 4th week using the Heart Disease Fact Questionnaire-2, Perceived Stress Scale, and Behavioural Risk Factor Surveillance System. RESULTS: After the SBCHDP programme, participants in the intervention group had a better awareness of CHD being the second leading cause of death in Singapore (X 2 = 6.486, p = 0.039), a better overall CHD knowledge level (t = 3.171, p = 0.002), and better behaviour concerning blood cholesterol control (X 2 = 4.54, p = 0.033) than participants in the control group. CONCLUSION: This pilot study partially confirmed the positive effects of the SBCHDP programme in improving awareness and knowledge of CHD among the working population. Due to the small sample size and short follow-up period, this study was underpowered to detect significant differences between groups. A full-scale longitudinal study is required in the future to confirm the effectiveness of the SBCHDP programme.


Assuntos
Doença da Artéria Coronariana/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Promoção da Saúde/métodos , Qualidade de Vida , Comportamento de Redução do Risco , Adulto , Conscientização , Feminino , Humanos , Estilo de Vida , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Fatores de Risco , Singapura , Smartphone , Inquéritos e Questionários
16.
Chembiochem ; 17(11): 990-4, 2016 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-26991964

RESUMO

The receptor tyrosine kinase EGFR is regulated by complex conformational changes, and this conformational control is disturbed in certain types of cancer. Many ligands are known to bind EGFR in its active conformation, thereby preventing ATP from binding. Only a few ligands are known to stabilize EGFR in its inactive conformation, thus providing novel strategies for perturbing EGFR activity. We report a direct binding assay that enables the identification of novel ligands that bind to and stabilize the inactive conformation of EGFR.


Assuntos
Receptores ErbB/metabolismo , Inibidores de Proteínas Quinases/metabolismo , Sítios de Ligação , Receptores ErbB/química , Receptores ErbB/genética , Cloridrato de Erlotinib/química , Cloridrato de Erlotinib/metabolismo , Lapatinib , Ligantes , Mutagênese Sítio-Dirigida , Ligação Proteica , Inibidores de Proteínas Quinases/química , Estrutura Terciária de Proteína , Quinazolinas/química , Quinazolinas/metabolismo , Espectrometria de Fluorescência
17.
Biomacromolecules ; 17(11): 3828-3837, 2016 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-27744703

RESUMO

One factor limiting the expansion of nanomedicines has been the high cost of the materials and processes required for their production. We present a continuous, scalable, low cost nanoencapsulation process, Flash Nanoprecipitation (FNP) that enables the production of nanocarriers (NCs) with a narrow size distribution using zein corn proteins. Zein is a low cost, GRAS protein (having the FDA status of "Generally Regarded as Safe") currently used in food applications, which acts as an effective encapsulant for hydrophobic compounds using FNP. The four-stream FNP configuration allows the encapsulation of very hydrophobic compounds in a way that is not possible with previous precipitation processes. We present the encapsulation of several model active compounds with as high as 45 wt % drug loading with respect to zein concentration into ∼100 nm nanocarriers. Three examples are presented: (1) the pro-drug antioxidant, vitamin E-acetate, (2) an anticholera quorum-sensing modulator CAI-1 ((S)-3-hydroxytridecan-4-one; CAI-1 that reduces Vibrio cholerae virulence by modulating cellular communication), and (3) hydrophobic fluorescent dyes with a range of hydrophobicities. The specific interaction between zein and the milk protein, sodium caseinate, provides stabilization of the NCs in PBS, LB medium, and in pH 2 solutions. The stability and size changes in the three media provide information on the mechanism of assembly of the zein/active/casein NC.


Assuntos
Antioxidantes/química , Portadores de Fármacos/química , Nanopartículas/química , Zeína/química , Antioxidantes/farmacologia , Caseínas/química , Portadores de Fármacos/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Nanomedicina , Nanopartículas/administração & dosagem , Tamanho da Partícula , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Percepção de Quorum/efeitos dos fármacos , Vitamina E/química , Zea mays/química , Zeína/farmacologia
18.
Nano Lett ; 15(4): 2235-41, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25651002

RESUMO

The rise of bacterial antibiotic resistance has created a demand for alternatives to traditional antibiotics. Attractive possibilities include pro- and anti-quorum sensing therapies that function by modulating bacterial chemical communication circuits. We report the use of Flash NanoPrecipitation to deliver the Vibrio cholerae quorum-sensing signal CAI-1 ((S)-3-hydroxytridecan-4-one) in a water dispersible form as nanoparticles. The particles activate V. cholerae quorum-sensing responses 5 orders of magnitude higher than does the identically administered free CAI-1 and are diffusive across in vivo delivery barriers such as intestinal mucus. This work highlights the promise of combining quorum-sensing strategies with drug delivery approaches for the development of next-generation medicines.


Assuntos
Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Cetonas/administração & dosagem , Nanocápsulas/química , Percepção de Quorum/efeitos dos fármacos , Percepção de Quorum/fisiologia , Cetonas/química , Nanocápsulas/ultraestrutura , Tamanho da Partícula
19.
PLoS One ; 19(2): e0288526, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38324614

RESUMO

It was necessary to have a tool that could predict the amount of protein and optimize the gene sequences to produce recombinant proteins efficiently. The Transim model published by Tuller et al. in 2018 can calculate the translation rate in E. coli using features on the mRNA sequence, achieving a Spearman correlation with the amount of protein per mRNA of 0.36 when tested on the dataset of operons' first genes in E. coli K-12 MG1655 genome. However, this Spearman correlation was not high, and the model did not fully consider the features of mRNA and protein sequences. Therefore, to enhance the prediction capability, our study firstly tried expanding the testing dataset, adding genes inside the operon, and using the microarray of the mRNA expression data set, thereby helping to improve the correlation of translation rate with the amount of protein with more than 0.42. Next, the applicability of 6 traditional machine learning models to calculate a "new translation rate" was examined using initiation rate and elongation rate as inputs. The result showed that the SVR algorithm had the most correlated new translation rates, with Spearman correlation improving to R = 0.6699 with protein level output and to R = 0.6536 with protein level per mRNA. Finally, the study investigated the degree of improvement when combining more features with the new translation rates. The results showed that the model's predictive ability to produce a protein per mRNA reached R = 0.6660 when using six features, while the correlation of this model's final translation rate to protein level was up to R = 0.6729. This demonstrated the model's capability to predict protein expression of a gene, rather than being limited to predicting expression by an mRNA and showed the model's potential for development into gene expression predicting tools.


Assuntos
Escherichia coli K12 , Escherichia coli , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Escherichia coli K12/genética , Escherichia coli K12/metabolismo , Genoma , Proteínas Recombinantes/metabolismo , Biossíntese de Proteínas/genética
20.
J Am Chem Soc ; 135(11): 4364-71, 2013 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-23437920

RESUMO

Nuclear receptor binding to coactivator proteins is an obligate first step in the regulation of gene transcription. Nuclear receptors preferentially bind to an LXXLL peptide motif which is highly conserved throughout the 300 or so natural coactivator proteins. This knowledge has shaped current understanding of this fundamental protein-protein interaction, and continues to inspire the search for new drug therapies. However, sequence specificity beyond the LXXLL motif and the molecular functioning of flanking residues still requires urgent addressing. Here, ribosome display has been used to reassess the estrogen receptor for new and enlarged peptide recognition motifs, leading to the discovery of a potent and highly evolved PXLXXLLXXP binding consensus. Molecular modeling and X-ray crystallography studies have provided the molecular insights on the role of the flanking prolines in priming the length of the α-helix and enabling optimal interactions of the α-helix dipole and its surrounding amino acids with the surface charge clamp and the receptor activation function 2. These findings represent new structural parameters for modulating the nuclear receptor-coactivator interaction based on linear sequences of proteinogenic amino acids and for the design of chemically modified inhibitors.


Assuntos
Peptídeos/química , Peptídeos/metabolismo , Prolina/química , Receptores de Estrogênio/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Sequência Consenso , Cristalografia por Raios X , Biblioteca Gênica , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Biblioteca de Peptídeos , Prolina/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína , Receptores de Estrogênio/química
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