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1.
Malays J Med Sci ; 29(6): 89-103, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36818909

RESUMEN

Background: Flexible work arrangements (FWAs) have been widely implemented during the COVID-19 pandemic. We aimed to assess the validity and reliability of the FWA perceived benefits and barriers (FWAPB) scale and subsequently, to determine the preference and perceived feasibility, perceived benefits and barriers, and readiness to implement FWA among healthcare workers. Methods: We conducted a cross-sectional study using a self-administered questionnaire in Miri Hospital. The questionnaire was administered via a web survey design (Google Forms). The convenience sampling method was applied to recruit respondents. All healthcare workers in Miri Hospital who could read and understand English were invited to participate in the study. Response process validation, exploratory factor analysis, reliability analyses and descriptive statistics were performed. Results: A total of 339 respondents participated. All items had satisfactory response process indices. Exploratory factor analysis revealed a three-factor structure. Items of 'perceived benefits-workplace management', 'perceived benefits-family life balance' and 'perceived barriers' have high internal consistency reliability (Cronbach's alpha = 0.852-0.884) and factor loadings. Flextime is preferred and perceived to be the most feasible work arrangement. Most agreed that FWA helps in improving social distancing among colleagues (mean = 3.65, standard deviation [SD] = 0.99) and reduces their exposure to COVID-19 (mean = 3.60, SD = 1.06). A total of 44.0% of the respondents agreed Miri Hospital is ready to implement FWA. Conclusion: The FWAPB is valid and reliable. Almost half of the respondents were positive towards the implementation of FWA. These findings contribute to the understanding of FWA, and thus increase the readiness and acceptance of such an arrangement.

2.
J Infect Dis ; 220(2): 203-212, 2019 06 19.
Artículo en Inglés | MEDLINE | ID: mdl-30901054

RESUMEN

BACKGROUND: Zika virus (ZIKV) infections have reemerged as a global health issue due to serious clinical complications. Development of specific serological assays to detect and differentiate ZIKV from other cocirculating flaviviruses for accurate diagnosis remains a challenge. METHODS: We investigated antibody responses in 51 acute ZIKV-infected adult patients from Campinas, Brazil, including 7 pregnant women who later delivered during the study. Using enzyme-linked immunosorbent assays, levels of antibody response were measured and specific epitopes identified. RESULTS: Several antibody-binding hot spots were identified in ZIKV immunogenic antigens, including membrane, envelope (E) and nonstructural protein 1 (NS1). Interestingly, specific epitopes (2 from E and 2 from NS1) strongly recognized by ZIKV-infected patients' antibodies were identified and were not cross-recognized by dengue virus (DENV)-infected patients' antibodies. Corresponding DENV peptides were not strongly recognized by ZIKV-infected patients' antibodies. Notably, ZIKV-infected pregnant women had specific epitope recognition for ZIKV NS1 (amino acid residues 17-34), which could be a potential serological marker for early ZIKV detection. CONCLUSIONS: This study identified 6 linear ZIKV-specific epitopes for early detection of ZIKV infections. We observed differential epitope recognition between ZIKV-infected and DENV-infected patients. This information will be useful for developing diagnostic methods that differentiate between closely related flaviviruses.


Asunto(s)
Epítopos/inmunología , Proteínas no Estructurales Virales/inmunología , Infección por el Virus Zika/inmunología , Virus Zika/inmunología , Enfermedad Aguda , Adolescente , Adulto , Anciano , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , Formación de Anticuerpos/inmunología , Brasil , Reacciones Cruzadas/inmunología , Dengue/inmunología , Dengue/virología , Virus del Dengue/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Serológicas , Adulto Joven , Infección por el Virus Zika/virología
3.
J Virol ; 89(22): 11420-37, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26339054

RESUMEN

UNLABELLED: Many viruses affect or exploit the phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway, a crucial prosurvival signaling cascade. We report that this pathway was strongly activated in cells upon infection with the Old World alphavirus Semliki Forest virus (SFV), even under conditions of complete nutrient starvation. We mapped this activation to the hyperphosphorylated/acidic domain in the C-terminal tail of SFV nonstructural protein nsP3. Viruses with a deletion of this domain (SFV-Δ50) but not of other regions in nsP3 displayed a clearly delayed and reduced capacity of Akt stimulation. Ectopic expression of the nsP3 of SFV wild type (nsP3-wt), but not nsP3-Δ50, equipped with a membrane anchor was sufficient to activate Akt. We linked PI3K-Akt-mTOR stimulation to the intracellular dynamics of viral replication complexes, which are formed at the plasma membrane and subsequently internalized in a process blocked by the PI3K inhibitor wortmannin. Replication complex internalization was observed upon infection of cells with SFV-wt and SFV mutants with deletions in nsP3 but not with SFV-Δ50, where replication complexes were typically accumulated at the cell periphery. In cells infected with the closely related chikungunya virus (CHIKV), the PI3K-Akt-mTOR pathway was only moderately activated. Replication complexes of CHIKV were predominantly located at the cell periphery. Exchanging the hypervariable C-terminal tail of nsP3 between SFV and CHIKV induced the phenotype of strong PI3K-Akt-mTOR activation and replication complex internalization in CHIKV. In conclusion, infection with SFV but not CHIKV boosts PI3K-Akt-mTOR through the hyperphosphorylated/acidic domain of nsP3 to drive replication complex internalization. IMPORTANCE: SFV and CHIKV are very similar in terms of molecular and cell biology, e.g., regarding replication and molecular interactions, but are strikingly different regarding pathology: CHIKV is a relevant human pathogen, causing high fever and joint pain, while SFV is a low-pathogenic model virus, albeit neuropathogenic in mice. We show that both SFV and CHIKV activate the prosurvival PI3K-Akt-mTOR pathway in cells but greatly differ in their capacities to do so: Akt is strongly and persistently activated by SFV infection but only moderately activated by CHIKV. We mapped this activation capacity to a region in nonstructural protein 3 (nsP3) of SFV and could functionally transfer this region to CHIKV. Akt activation is linked to the subcellular dynamics of replication complexes, which are efficiently internalized from the cell periphery for SFV but not CHIKV. This difference in signal pathway stimulation and replication complex localization may have implications for pathology.


Asunto(s)
Virus Chikungunya/metabolismo , Fosfatidilinositol 3-Quinasa/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas de Unión al ARN/genética , Virus de los Bosques Semliki/metabolismo , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Proteínas no Estructurales Virales/genética , Infecciones por Alphavirus/virología , Androstadienos/farmacología , Animales , Línea Celular Tumoral , Virus Chikungunya/genética , Cricetinae , Activación Enzimática , Humanos , Ratones , Naftiridinas/farmacología , Inhibidores de las Quinasa Fosfoinosítidos-3 , Fosforilación , Estructura Terciaria de Proteína/genética , Virus de los Bosques Semliki/genética , Transducción de Señal , Sirolimus/farmacología , Serina-Treonina Quinasas TOR/metabolismo , Internalización del Virus/efectos de los fármacos , Replicación Viral , Wortmanina
4.
J Virol ; 86(10): 5674-85, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22438538

RESUMEN

Autophagy is a cellular process that sequesters cargo in double-membraned vesicles termed autophagosomes and delivers this cargo to lysosomes to be degraded. It is enhanced during nutrient starvation to increase the rate of amino acid turnover. Diverse roles for autophagy have been reported for viral infections, including the assembly of viral replication complexes on autophagic membranes and protection of host cells from cell death. Here, we show that autophagosomes accumulate in Semliki Forest virus (SFV)-infected cells. Despite this, disruption of autophagy had no effect on the viral replication rate or formation of viral replication complexes. Also, viral proteins rarely colocalized with autophagosome markers, suggesting that SFV did not utilize autophagic membranes for its replication. Further, we found that SFV infection, unlike nutrient starvation, did not inactivate the constitutive negative regulator of autophagosome formation, mammalian target of rapamycin, suggesting that SFV-dependent accumulation of autophagosomes was not a result of enhanced autophagosome formation. In starved cells, addition of NH(4)Cl, an inhibitor of lysosomal acidification, caused a dramatic accumulation of starvation-induced autophagosomes, while in SFV-infected cells, NH(4)Cl did not further increase levels of autophagosomes. These results suggest that accumulation of autophagosomes in SFV-infected cells is due to an inhibition of autophagosome degradation rather than enhanced rates of autophagosome formation. Finally, we show that the accumulation of autophagosomes in SFV-infected cells is dependent on the expression of the viral glycoprotein spike complex.


Asunto(s)
Infecciones por Alphavirus/fisiopatología , Autofagia , Glicoproteínas/metabolismo , Fagosomas/metabolismo , Virus de los Bosques Semliki/fisiología , Proteínas Estructurales Virales/metabolismo , Infecciones por Alphavirus/metabolismo , Infecciones por Alphavirus/virología , Animales , Línea Celular , Cricetinae , Glicoproteínas/genética , Humanos , Ratones , Virus de los Bosques Semliki/genética , Proteínas Estructurales Virales/genética
5.
J Crohns Colitis ; 2023 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-37941436

RESUMEN

BACKGROUND AND AIMS: We sought to determine whether six commonly used immunosuppressive regimens were associated with lower antibody responses after seasonal influenza vaccination in patients with IBD. METHODS: We conducted a prospective study including 213 IBD patients and 53 healthy controls; 165 who had received seasonal influenza vaccine and 101 who had not. IBD medications included infliximab, thiopurines, infliximab and thiopurine combination therapy, ustekinumab, vedolizumab or tofacitinib. The primary outcome was antibody responses against influenza/A H3N2 and A/H1N1, compared to controls, adjusting for age, prior vaccination and interval between vaccination and sampling. RESULTS: Lower antibody responses against influenza A/H3N2 were observed in patients on infliximab (Geometric Mean Ratio 0.35 [95% CI 0.20-0.60], p=0.0002), combination of infliximab and thiopurine therapy (0.46 [0.27-0.79], p=0.0050) and tofacitinib (0.28 [0.14-0.57], p=0.0005) compared to controls. Lower antibody responses against A/H1N1 were observed in patients on infliximab (0.29 [0.15-0.56], p=0.0003), combination of infliximab and thiopurine therapy (0.34 [0.17-0.66], p=0.0016), thiopurine monotherapy (0.46 [0.24-0.87], p=0.017) and tofacitinib (0.23 [0.10-0.56], p=0.0013). Ustekinumab and vedolizumab were not associated with reduced antibody responses against A/H3N2 or A/H1N1. Vaccination in the previous year was associated with higher antibody responses to A/H3N2. Vaccine-induced anti-SARS-CoV-2 antibody concentration weakly correlated with antibodies against H3N2 (r=0.27; p=0.0004) and H1N1 (r=0.33; p<0.0001). CONCLUSIONS: Vaccination in both the 2020-2021 and 2021-2022 seasons was associated with significantly higher antibody responses to influenza/A than no vaccination or vaccination in 2021-2022 alone. Infliximab and tofacitinib are associated with lower binding antibody responses to Influenza/A, similar to COVID-19 vaccine-induced antibody responses.

7.
PLoS One ; 13(4): e0195956, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29684045

RESUMEN

Tenovin-6 is the most studied member of a family of small molecules with antitumour activity in vivo. Previously, it has been determined that part of the effects of tenovin-6 associate with its ability to inhibit SirT1 and activate p53. However, tenovin-6 has also been shown to modulate autophagic flux. Here we show that blockage of autophagic flux occurs in a variety of cell lines in response to certain tenovins, that autophagy blockage occurs regardless of the effect of tenovins on SirT1 or p53, and that this blockage is dependent on the aliphatic tertiary amine side chain of these molecules. Additionally, we evaluate the contribution of this tertiary amine to the elimination of proliferating melanoma cells in culture. We also demonstrate that the presence of the tertiary amine is sufficient to lead to death of tumour cells arrested in G1 phase following vemurafenib treatment. We conclude that blockage of autophagic flux by tenovins is necessary to eliminate melanoma cells that survive B-Raf inhibition and achieve total tumour cell kill and that autophagy blockage can be achieved at a lower concentration than by chloroquine. This observation is of great relevance as relapse and resistance are frequently observed in cancer patients treated with B-Raf inhibitors.


Asunto(s)
Antineoplásicos/farmacología , Autofagia/efectos de los fármacos , Benzamidas/farmacología , Indoles/farmacología , Melanoma/genética , Proteínas Proto-Oncogénicas B-raf/genética , Sulfonamidas/farmacología , Antineoplásicos/química , Benzamidas/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Sinergismo Farmacológico , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Melanoma/tratamiento farmacológico , Estructura Molecular , Mutación , Sirtuinas/genética , Proteína p53 Supresora de Tumor/genética , Vemurafenib
8.
PLoS Negl Trop Dis ; 9(1): e3445, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25568956

RESUMEN

Chikungunya virus (CHIKV) and clinically-related arboviruses cause large epidemics with serious economic and social impact. As clinical symptoms of CHIKV infections are similar to several flavivirus infections, good detection methods to identify CHIKV infection are desired for improved treatment and clinical management. The strength of anti-E2EP3 antibody responses was explored in a longitudinal study on 38 CHIKV-infected patients. We compared their anti-E2EP3 responses with those of patients infected with non-CHIKV alphaviruses, or flaviviruses. E2EP3 cross-reactive samples from patients infected with non-CHIKV viruses were further analyzed with an in vitro CHIKV neutralization assay. CHIKV-specific anti-E2EP3 antibody responses were detected in 72% to 100% of patients. Serum samples from patients infected with other non-CHIKV alphaviruses were cross-reactive to E2EP3. Interestingly, some of these antibodies demonstrated clearly in vitro CHIKV neutralizing activity. Contrastingly, serum samples from flaviviruses-infected patients showed a low level of cross-reactivity against E2EP3. Using CHIKV E2EP3 as a serology marker not only allows early detection of CHIKV specific antibodies, but would also allow the differentiation between CHIKV infections and flavivirus infections with 93% accuracy, thereby allowing precise acute febrile diagnosis and improving clinical management in regions newly suffering from CHIKV outbreaks including the Americas.


Asunto(s)
Anticuerpos Antivirales/sangre , Infecciones por Arbovirus/virología , Virus Chikungunya/inmunología , Especificidad de Anticuerpos , Infecciones por Arbovirus/sangre , Infecciones por Arbovirus/inmunología , Biomarcadores , Reacciones Cruzadas , Humanos , Inmunoglobulina G/sangre , Estudios Seroepidemiológicos , Proteínas Virales
9.
Mol Biol Cell ; 23(24): 4701-12, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23087212

RESUMEN

Dynamic, mRNA-containing stress granules (SGs) form in the cytoplasm of cells under environmental stresses, including viral infection. Many viruses appear to employ mechanisms to disrupt the formation of SGs on their mRNAs, suggesting that they represent a cellular defense against infection. Here, we report that early in Semliki Forest virus infection, the C-terminal domain of the viral nonstructural protein 3 (nsP3) forms a complex with Ras-GAP SH3-domain-binding protein (G3BP) and sequesters it into viral RNA replication complexes in a manner that inhibits the formation of SGs on viral mRNAs. A viral mutant carrying a C-terminal truncation of nsP3 induces more persistent SGs and is attenuated for propagation in cell culture. Of importance, we also show that the efficient translation of viral mRNAs containing a translation enhancer sequence also contributes to the disassembly of SGs in infected cells. Furthermore, we show that the nsP3/G3BP interaction also blocks SGs induced by other stresses than virus infection. This is one of few described viral mechanisms for SG disruption and underlines the role of SGs in antiviral defense.


Asunto(s)
Proteínas Portadoras/metabolismo , Gránulos Citoplasmáticos/metabolismo , Proteínas de Unión al ARN/metabolismo , Virus de los Bosques Semliki/metabolismo , Proteínas no Estructurales Virales/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Animales , Sitios de Unión/genética , Proteínas Portadoras/genética , Línea Celular , Células Cultivadas , Gránulos Citoplasmáticos/virología , ADN Helicasas , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Interacciones Huésped-Patógeno , Humanos , Immunoblotting , Ratones , Microscopía Confocal , Mutación , Proteínas de Unión a Poli-ADP-Ribosa , Unión Proteica , Biosíntesis de Proteínas , ARN Helicasas , Proteínas con Motivos de Reconocimiento de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/genética , Virus de los Bosques Semliki/genética , Virus de los Bosques Semliki/fisiología , Estrés Fisiológico , Proteínas no Estructurales Virales/genética
10.
Autophagy ; 6(5): 634-41, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20458170

RESUMEN

Autophagy is a cellular degradation process with an increasingly recognised importance in many biological pathways such as nutrient sensing, stress responses and development. We present a straightforward assay for autophagy which combines the sensitivity of the EGFP-LC3 reporter protein with the throughput capacity and quantitative power of flow cytometry. Because saponin extraction is specific for the non-autophagosome associated EGFP-LC3-I form of the protein, flow cytometry can be used to measure total fluorescence of saponin extracted HOS-EGFP-LC3 cells as a measure of the levels of autophagosome associated EGFP-LC3-II. Combined with inhibitors of degradation, we have adapted this assay to differentiate between constitutive and induced autophagy and to quantify the changes in flux of the system. Moreover, using direct antibody staining for the endogenous LC3 protein, we have extended this assay to the detection of autophagosome formation in non-transfected cells.


Asunto(s)
Autofagia , Bioensayo/métodos , Citometría de Flujo/métodos , Animales , Autofagia/efectos de los fármacos , Cloroquina/farmacología , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Espacio Intracelular/efectos de los fármacos , Espacio Intracelular/metabolismo , Ratones , Proteínas Asociadas a Microtúbulos/metabolismo , Saponinas/metabolismo
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