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1.
Anal Chem ; 96(35): 14168-14177, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39163401

RESUMO

Antibiotic resistance can rapidly spread through bacterial populations via bacterial conjugation. The bacterial membrane has an important role in facilitating conjugation, thus investigating the effects on the bacterial membrane caused by conjugative plasmids, antibiotic resistance, and genes involved in conjugation is of interest. Analysis of bacterial membranes was conducted using gas cluster ion beam-secondary ion mass spectrometry (GCIB-SIMS). The complexity of the data means that data analysis is important for the identification of changes in the membrane composition. Preprocessing of data and several analytical methods for identification of changes in bacterial membranes have been investigated. GCIB-SIMS data from Escherichia coli samples were subjected to principal components analysis (PCA), principal components-canonical variate analysis (PC-CVA), and Random Forests (RF) data analysis with the aim of extracting the maximum biological information. The influence of increasing replicate data was assessed, and the effect of diminishing biological variation was studied. Optimized m/z region-specific scaling provided improved clustering, with an increase in biologically significant peaks contributing to the loadings. PC-CVA improved clustering, provided clearer loadings, and benefited from larger data sets collected over several months. RF required larger sample numbers and while showing overlap with the PC-CVA, produced additional peaks of interest. The combination of PC-CVA and RF allowed very subtle differences between bacterial strains and growth conditions to be elucidated for the first time. Specifically, comparative analysis of an E. coli strain with and without the F-plasmid revealed changes in cyclopropanation of fatty acids, where the addition of the F-plasmid led to a reduction in cyclopropanation.


Assuntos
Escherichia coli , Análise de Componente Principal , Espectrometria de Massa de Íon Secundário , Escherichia coli/efeitos dos fármacos , Espectrometria de Massa de Íon Secundário/métodos , Antibacterianos/farmacologia , Membrana Celular/metabolismo , Membrana Celular/química , Farmacorresistência Bacteriana , Resistência Microbiana a Medicamentos , Algoritmo Florestas Aleatórias
2.
BMC Infect Dis ; 24(1): 483, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730352

RESUMO

BACKGROUND: Monkeypox (Mpox) is an important human pathogen without etiological treatment. A viral-host interactome study may advance our understanding of molecular pathogenesis and lead to the discovery of suitable therapeutic targets. METHODS: GEO Expression datasets characterizing mRNA profile changes in different host responses to poxviruses were analyzed for shared pathway identification, and then, the Protein-protein interaction (PPI) maps were built. The viral gene expression datasets of Monkeypox virus (MPXV) and Vaccinia virus (VACV) were used to identify the significant viral genes and further investigated for their binding to the library of targeting molecules. RESULTS: Infection with MPXV interferes with various cellular pathways, including interleukin and MAPK signaling. While most host differentially expressed genes (DEGs) are predominantly downregulated upon infection, marked enrichments in histone modifiers and immune-related genes were observed. PPI analysis revealed a set of novel virus-specific protein interactions for the genes in the above functional clusters. The viral DEGs exhibited variable expression patterns in three studied cell types: primary human monocytes, primary human fibroblast, and HeLa, resulting in 118 commonly deregulated proteins. Poxvirus proteins C6R derived protein K7 and K7R of MPXV and VACV were prioritized as targets for potential therapeutic interventions based on their histone-regulating and immunosuppressive properties. In the computational docking and Molecular Dynamics (MD) experiments, these proteins were shown to bind the candidate small molecule S3I-201, which was further prioritized for lead development. RESULTS: MPXV circumvents cellular antiviral defenses by engaging histone modification and immune evasion strategies. C6R-derived protein K7 binding candidate molecule S3I-201 is a priority promising candidate for treating Mpox.


Assuntos
Interações Hospedeiro-Patógeno , Monkeypox virus , Vaccinia virus , Proteínas Virais , Humanos , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vaccinia virus/genética , Vaccinia virus/metabolismo , Células HeLa , Monkeypox virus/genética , Mpox/virologia , Mapas de Interação de Proteínas , Perfilação da Expressão Gênica , Simulação de Acoplamento Molecular , Poxviridae/genética , Poxviridae/metabolismo , Fibroblastos/virologia , Fibroblastos/metabolismo
3.
J Med Virol ; 95(4): e28697, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36951428

RESUMO

It is believed that human papilloma virus infection (HPV), which is caused by the DNA virus, is the most prominent factor contributing to sexually transmitted disease (STD) in the world, with males having a prevalence rate of 3.5%-45% while that women are 2%-44%. Infertility is a rising problem on a global basis, affecting anywhere from 10% to 30% of couples who have reached reproductive age. This study aims to investigate the existing research on HPV, its connection to male infertility, and how it could be a helpful tool for medical professionals managing HPV in the context of reproductive health care. Infection with HPV has been identified as a risk factor for several spontaneous abortions; however, there is a lack of evidence on how HPV influences individuals undergoing assisted reproductive technology (ART) in terms of live births. The significance of the immune response to HPV-infected male reproductive system cells and its effect on embryos, as well as the oxidative stress generated by high-risk HPV DNA damage and genomic instability, is discussed in this review. Further, the association between male individuals infected with HPV and asthenozoospermia should provide a compelling case for vaccinating young people against HPV.


Assuntos
Infertilidade Masculina , Infecções por Papillomavirus , Gravidez , Humanos , Masculino , Feminino , Adolescente , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/epidemiologia , Papillomavirus Humano , Saúde Reprodutiva , Papillomaviridae/genética
4.
Health Qual Life Outcomes ; 21(1): 27, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36949507

RESUMO

BACKGROUND: Over the past few decades the benefits of assessing Quality of Life (QoL) and mental health in patients with Type 2 Diabetes Mellitus (T2DM) have steadily increased with limited studies relating to the most useful method to assess these patients. This study aims to identify, review, summarise, and evaluate the methodological quality for the most validated commonly used health-related QoL and mental health assessment measurements in diabetic patients. METHODS: All original articles published on PubMed, MedLine, OVID, The Cochrane Register, Web of Science Conference Proceedings and Scopus databases were systematically reviewed between 2011 and 2022. A search strategy was developed for each database using all possible combinations of the following keywords: "type 2 diabetes mellitus", "quality of life", mental health", and "questionnaires". Studies conducted on patients with T2DM of ≥ 18 years with or without other clinical illnesses were included. Articles designed as a literature or systematic review conducted on either children or adolescents, healthy adults and/or with a small sample size were excluded. RESULTS: A total of 489 articles were identified in all of the electronic medical databases. Of these articles, 40 were shown to meet our eligibility criteria to be included in this systematic review. Approximately, 60% of these studies were cross-sectional, 22.5% were clinical trials, and 17.5% of cohort studies. The top commonly used QoL measurements are the SF-12 identified in 19 studies, the SF-36, included in 16 studies, and the EuroQoL EQ-5D, found in 8 studies. Fifteen (37.5%) studies used only one questionnaire, while the remaining reviewed (62.5%) used more than one questionnaire. Finally, the majority (90%) of studies reported using self-administered questionnaires and only 4 used interviewer mode of administration. CONCLUSION: Our evidence highlights that the commonly used questionnaire to evaluate the QoL and mental health is the SF-12 followed by SF-36. Both of these questionnaires are validated, reliable and supported in different languages. Moreover, using single or combined questionnaires as well as the mode of administration depends on the clinical research question and aim of the study.


Assuntos
Diabetes Mellitus Tipo 2 , Adulto , Criança , Adolescente , Humanos , Qualidade de Vida , Saúde Mental , Inquéritos e Questionários
5.
JAMA ; 330(21): 2106-2114, 2023 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-38051324

RESUMO

Importance: Transparent reporting of randomized trials is essential to facilitate critical appraisal and interpretation of results. Factorial trials, in which 2 or more interventions are assessed in the same set of participants, have unique methodological considerations. However, reporting of factorial trials is suboptimal. Objective: To develop a consensus-based extension to the Consolidated Standards of Reporting Trials (CONSORT) 2010 Statement for factorial trials. Design: Using the Enhancing the Quality and Transparency of Health Research (EQUATOR) methodological framework, the CONSORT extension for factorial trials was developed by (1) generating a list of reporting recommendations for factorial trials using a scoping review of methodological articles identified using a MEDLINE search (from inception to May 2019) and supplemented with relevant articles from the personal collections of the authors; (2) a 3-round Delphi survey between January and June 2022 to identify additional items and assess the importance of each item, completed by 104 panelists from 14 countries; and (3) a hybrid consensus meeting attended by 15 panelists to finalize the selection and wording of items for the checklist. Findings: This CONSORT extension for factorial trials modifies 16 of the 37 items in the CONSORT 2010 checklist and adds 1 new item. The rationale for the importance of each item is provided. Key recommendations are (1) the reason for using a factorial design should be reported, including whether an interaction is hypothesized, (2) the treatment groups that form the main comparisons should be clearly identified, and (3) for each main comparison, the estimated interaction effect and its precision should be reported. Conclusions and Relevance: This extension of the CONSORT 2010 Statement provides guidance on the reporting of factorial randomized trials and should facilitate greater understanding of and transparency in their reporting.


Assuntos
Revelação , Ensaios Clínicos Controlados Aleatórios como Assunto , Projetos de Pesquisa , Humanos , Lista de Checagem , Consenso , Revelação/normas , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Padrões de Referência , Projetos de Pesquisa/normas
6.
Angew Chem Int Ed Engl ; 62(15): e202217993, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36749546

RESUMO

Aberrant functioning of the proteasome has been associated with crucial pathologic conditions including neurodegeneration. Yet, the complex underlying causes at the cellular level remain unclear and there are conflicting reports of neuroprotective to neurodegenerative effects of proteasomal inhibitors such as lactacystin that are utilised as models for neurodegenerative diseases. The conflicting results may be associated with different dose regimes of lactacystin and hence we have performed a dose dependent study of the effects of lactacystin to identify concurrent changes in the cell membrane lipid profile and the dynamics of exocytosis using a combination of surface sensitive mass spectrometry and single cell amperometry. Significant changes of negatively charged lipids were associated with different lactacystin doses that showed a weak correlation with exocytosis while changes in PE and PE-O lipids showed dose dependent changes correlated with initial pore formation and total release of vesicle content respectively.


Assuntos
Lipídeos de Membrana , Inibidores de Proteassoma , Inibidores de Proteassoma/farmacologia , Espectrometria de Massas , Exocitose
7.
Molecules ; 27(15)2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35897946

RESUMO

Ethanol is the most commonly used recreational drug worldwide. This study describes the development and validation of a headspace gas chromatography flame ionisation detection (HS-GC-FID) method using dual columns and detectors for simultaneous separation and quantitation. The use of a dual-column, dual-detector HS-GC-FID to quantitate ethanol is a common analytical technique in forensic toxicology; however, most analytical systems utilise pressure-balance injection rather than a simplified gas-tight syringe, as per this technique. This study is the first to develop and validate a technique that meets the specifications of the United Kingdom's requirements for road traffic toxicology testing using a Shimadzu GC-2014 gas-tight syringe. The calibration ranged from 10 to 400 mg/100 mL, with a target minimum linearity of r2 > 0.999, using tertiary butanol as the internal standard marker. The method has an expanded uncertainty at 99.73% confidence of 3.64% at 80 mg/100 mL, which is the blood alcohol limit for drink driving in England and Wales. In addition, at 200 mg%­the limit at which a custodial sentence may be imposed on the defendant­the expanded uncertainty was 1.95%. For both the 80 mg% and 200 mg% concentrations, no bias was present in the analytical method. This method displays sufficient separation for other alcohols, such as methanol, isopropanol, acetaldehyde, and acetone. The validation of this technique complies with the recommended laboratory guidelines set out by United Kingdom and Ireland Association of Forensic Toxicologists (UKIAFT), the recently issued Laboratory 51 guidelines by the United Kingdom Accreditation Service (UKAS), and the criteria set out by the California Code of Regulations (CCR), 17 CCR § 1220.1.


Assuntos
Etanol , Seringas , Acetaldeído/análise , Cromatografia Gasosa , Etanol/análise , Ionização de Chama/métodos
8.
AAPS PharmSciTech ; 23(1): 48, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34984564

RESUMO

Gefitinib is a tyrosine kinase inhibitor that is intended for oral administration yet suffers poor bioavailability along with undesirable side effects. To enhance its solubility and allow colon targeting, gefitinib (ZD) and blends of different ratios of polymers (ternary dispersion) were prepared in organic solution, and solid dispersions were generated employing the spray drying (SD) technique. The methylmethacrylate polymer Eudragit S 100 was incorporated for colon targeting; polyvinylpyrrolidone (PVP) and hydroxypropyl methyl cellulose (HPMC) were utilised to improve the solubility of ZD. SEM, DSC, XRPD, FT-IR, dissolution and cytotoxicity studies were undertaken to characterise and evaluate the developed formulations. SEM images revealed that the rod-shaped crystals of ZD were transformed into collapsed spheres with smaller particle size in the spray-dried particles. DSC, FTIR and XRPD studies showed that ZD loaded in the spray-dried dispersions was amorphous. ZD dissolution and release studies revealed that while a significant (P < 0.05) increase in the ZD dissolution and release was observed from HPMC-based solid dispersion at pH 7.2 (up to 95% in 15 h), practically no drug was released at pH 1.2 and pH 6.5. Furthermore, the HPMC-based solid dispersions displayed enhanced mucoadhesive properties compared with PVP-based ones. Interestingly, cell viability studies using the neutral red assay showed that PVP and HPMC-based solid dispersions had no additional inhibitory effect on Caco-2 cell line compared to the pure drug.


Assuntos
Secagem por Atomização , Células CACO-2 , Liberação Controlada de Fármacos , Gefitinibe , Humanos , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Int Wound J ; 19(2): 370-379, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34240793

RESUMO

Optimal treatment of full-thickness skin injuries requires dermal and epidermal replacement. To spare donor dermis, dermal substitutes can be used ahead of split-thickness skin graft (STSG) application. However, this two-stage procedure requires an additional general anaesthetic, often prolongs hospitalisation, and increases outpatient services. Although a few case series have described successful single-stage reconstructions, with application of both STSG and dermal substitute at the index operation, we have little understanding of how the physical characteristics of dermal substitutes affects the success of a single-stage procedure. Here, we evaluated several dermal substitutes to optimise single-stage skin replacement in a preclinical porcine model. A porcine full-thickness excisional wound model was used to evaluate the following dermal substitutes: autologous dermal graft (ADG; thicknesses 0.15-0.60 mm), Integra (0.4-0.8 mm), Alloderm (0.9-1.6 mm), and chitosan-based hydrogel (0.1-0.2 mm). After excision, each wound was treated with either a dermal substitute followed by STSG or STSG alone (control). Endpoints included graft take at postoperative days (PODs) 7 and 14, wound closure at POD 28, and wound contracture from POD 28-120. Graft take was highest in the STSG alone and hydrogel groups at POD 14 (86.9% ± 19.5% and 81.3% ± 12.3%, respectively; P < .001). There were no differences in graft take at POD 7 or in wound closure at POD 28, though highest rates of wound closure were seen in the STSG alone and hydrogel groups (93.6% ± 9.1% and 99.8% ± 0.5%, respectively). ADG-treated wounds demonstrated the least amount of wound contracture at each time point. Increase dermal substitute thickness was associated with worse percent graft take at PODs 14 and 28 (Spearman ρ of -0.50 and -0.45, respectively; P < .001). In this preclinical single-stage skin reconstruction model, thinner ADG and hydrogel dermal substitutes outperformed thicker dermal substitutes. Both substitute thickness and composition affect treatment success. Further preclinical and clinical studies to optimise this treatment modality are warranted.


Assuntos
Transplante de Pele , Pele Artificial , Animais , Sobrevivência de Enxerto , Pele , Suínos , Cicatrização
10.
Anal Bioanal Chem ; 413(16): 4181-4194, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33974088

RESUMO

This work assesses the potential of new water cluster-based ion beams for improving the capabilities of secondary ion mass spectrometry (SIMS) for in situ lipidomics. The effect of water clusters was compared to carbon dioxide clusters, along with the effect of using pure water clusters compared to mixed water and carbon dioxide clusters. A signal increase was found when using pure water clusters. However, when analyzing cells, a more substantial signal increase was found in positive ion mode when the water clusters also contained carbon dioxide, suggesting that additional reactions are in play. The effects of using a water primary ion beam on a more complex sample were investigated by analyzing brain tissue from an Alzheimer's disease transgenic mouse model. The results indicate that the ToF-SIMS results are approaching those from MALDI as ToF-SIMS was able to image lyso-phosphocholine (LPC) lipids, a lipid class that for a long time has eluded detection during SIMS analyses. Gangliosides, sulfatides, and cholesterol were also imaged.


Assuntos
Doença de Alzheimer/patologia , Encéfalo/patologia , Dióxido de Carbono/análise , Lipídeos/análise , Água/análise , Animais , Química Encefálica , Modelos Animais de Doenças , Humanos , Células MCF-7 , Camundongos , Camundongos Transgênicos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massa de Íon Secundário
11.
Anal Bioanal Chem ; 413(2): 445-453, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33130974

RESUMO

Changes in the membrane composition of sub-populations of cells can influence different properties with importance to tumour growth, metastasis and treatment efficacy. In this study, we use correlated fluorescence microscopy and ToF-SIMS with C60+ and (CO2)6k+ ion beams to identify and characterise sub-populations of cells based on successful transfection leading to over-expression of CCTδ, a component of the multi-subunit molecular chaperone named chaperonin-containing tailless complex polypeptide 1 (CCT). CCT has been linked to increased cell growth and proliferation and is known to affect cell morphology but corresponding changes in lipid composition of the membrane have not been measured until now. Multivariate analysis of the surface mass spectra from single cells, focused on the intact lipid ions, indicates an enrichment of phosphatidylethanolamine species in the transfected cells. While the lipid changes in this case are driven by the structural changes in the protein cytoskeleton, the consequence of phosphatidylethanolamine enrichment may have additional implications in cancer such as increased membrane fluidity, increased motility and an ability to adapt to a depletion of unsaturated lipids during cancer cell proliferation. This study demonstrates a successful fluorescence microscopy-guided cell by cell membrane lipid analysis with broad application to biological investigation.Graphical abstract.


Assuntos
Microscopia de Fluorescência/métodos , Chaperonas Moleculares/análise , Neoplasias/metabolismo , Fosfatidiletanolaminas/análise , Espectrometria de Massa de Íon Secundário/métodos , Animais , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Proliferação de Células , Citoesqueleto/metabolismo , Ouro , Proteínas de Fluorescência Verde/metabolismo , Íons , Lipídeos/química , Melanoma Experimental , Camundongos , Análise Multivariada , Análise de Componente Principal
12.
Int J Mol Sci ; 22(17)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34502027

RESUMO

Monocytes play a key role in cardiovascular disease (CVD) as their influx into the vessel wall is necessary for the development of an atherosclerotic plaque. Monocytes are, however, heterogeneous differentiating from classical monocytes through the intermediate subset to the nonclassical subset. While it is recognized that the percentage of intermediate and nonclassical monocytes are higher in individuals with CVD, accompanying changes in inflammatory markers suggest a functional impact on disease development that goes beyond the increased proportion of these 'inflammatory' monocyte subsets. Furthermore, emerging evidence indicates that changes in monocyte proportion and function arise in dyslipidemia, with lipid lowering medication having some effect on reversing these changes. This review explores the nature and number of monocyte subsets in CVD addressing what they are, when they arise, the effect of lipid lowering treatment, and the possible implications for plaque development. Understanding these associations will deepen our understanding of the clinical significance of monocytes in CVD.


Assuntos
Aterosclerose/etiologia , Doenças Cardiovasculares/etiologia , Dislipidemias/complicações , Monócitos , Animais , Aterosclerose/fisiopatologia , Doenças Cardiovasculares/fisiopatologia , Humanos , Inflamação
13.
J Neurochem ; 154(1): 84-98, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32141089

RESUMO

There is emerging evidence that amyloid beta (Aß) aggregates forming neuritic plaques lead to impairment of the lipid-rich myelin sheath and glia. In this study, we examined focal myelin lipid alterations and the disruption of the myelin sheath associated with amyloid plaques in a widely used familial Alzheimer's disease (AD) mouse model; 5xFAD. This AD mouse model has Aß42 peptide-rich plaque deposition in the brain parenchyma. Matrix-assisted laser desorption/ionization imaging mass spectrometry of coronal brain tissue sections revealed focal Aß plaque-associated depletion of multiple myelin-associated lipid species including sulfatides, galactosylceramides, and specific plasmalogen phopshatidylethanolamines in the hippocampus, cortex, and on the edges of corpus callosum. Certain phosphatidylcholines abundant in myelin were also depleted in amyloid plaques on the edges of corpus callosum. Further, lysophosphatidylethanolamines and lysophosphatidylcholines, implicated in neuroinflammation, were found to accumulate in amyloid plaques. Double staining of the consecutive sections with fluoromyelin and amyloid-specific antibody revealed amyloid plaque-associated myelin sheath disruption on the edges of the corpus callosum which is specifically correlated with plaque-associated myelin lipid loss only in this region. Further, apolipoprotein E, which is implicated in depletion of sulfatides in AD brain, is deposited in all the Aß plaques which suggest apolipoprotein E might mediate sulfatide depletion as a consequence of an immune response to Aß deposition. This high-spatial resolution matrix-assisted laser desorption/ionization imaging mass spectrometry study in combination with (immuno) fluorescence staining of 5xFAD mouse brain provides new understanding of morphological, molecular and immune signatures of Aß plaque pathology-associated myelin lipid loss and myelin degeneration in a brain region-specific manner. Read the Editorial Highlight for this article on page 7.


Assuntos
Doença de Alzheimer/patologia , Apolipoproteínas E/metabolismo , Encéfalo/patologia , Bainha de Mielina/metabolismo , Placa Amiloide/patologia , Doença de Alzheimer/metabolismo , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Lipidômica/métodos , Lipídeos/análise , Camundongos , Camundongos Transgênicos , Placa Amiloide/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
14.
Anal Chem ; 92(24): 15811-15817, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33259206

RESUMO

In mass spectrometry (MS), a major loss of ions can readily occur during their transfer from atmospheric pressure to a lower pressure, which limits performance. Here, we report an ion funnel that can be used to effectively focus ions at ambient pressure (∼777 Torr) to significantly enhance performance in electrospray ionization (ESI) MS. For seven singly charged test ions (m/z 124-1131), the ambient pressure ion funnel (APIF) is demonstrated to improve ion abundances, sensitivity, and detection limits by up to factors of ∼17, ∼16, and ∼3, respectively, compared to the operation of conventional ESI-MS. Simulated ion trajectories were used to rationalize the enhanced performance of the APIF, which is attributed primarily to using a relatively high RF field amplitude to radially confine ions, a high DC field, and a wide exit ring electrode. The effective focusing of ions at ambient pressures should be beneficial in the future for improving the performance of (i) additional methods that ionize molecules at atmospheric pressure, (ii) ambient pressure ion mobility-based instruments, and (iii) high flow rate liquid chromatography mass spectrometry platforms.

15.
Anal Chem ; 92(6): 4468-4474, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32083845

RESUMO

Dielectric barrier discharge ionization (DBDI) is an emerging technique for ionizing volatile molecules directly from complex mixtures for sensitive detection by mass spectrometry (MS). In conventional DBDI, a high frequency and high voltage waveform with pulse widths of ∼50 µs (and ∼50 µs between pulses) is applied across a dielectric barrier and a gas to generate "low temperature plasma." Although such a source has the advantages of being compact, economical, robust, and sensitive, background ions from the ambient environment can be formed in high abundances, which limits performance. Here, we demonstrate that high voltage pulse widths as narrow as 100 ns with a pulse-to-pulse delay of ∼900 µs can significantly reduce background chemical noise and increase ion signal. Compared to microsecond pulses, ∼800 ns pulses can be used to increase the signal-to-noise and signal-to-background chemical noise ratios in DBDI-MS by up to 172% and 1300% for six analytes, including dimethyl methylphosphonate (DMMP), 3-octanone, and perfluorooctanoic acid. Using nanosecond pulses, the detection limit for DMMP and PFOA in human blood plasma can be lowered by more than a factor of 2 in comparison to microsecond pulses. In "nanopulsed" plasma ionization, the extent of internal energy deposition is as low as or lower than in electrospray ionization and micropulsed plasma ionization based on thermometer ion measurements. Overall, nanosecond high-voltage pulsing can be used to significantly improve the performance of DBDI-MS and potentially other ion sources involving high voltage waveforms.

16.
BMC Geriatr ; 20(1): 429, 2020 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-33109091

RESUMO

BACKGROUND: Fried's Phenotype Model of Frailty (PMF) postulates that frailty is a syndrome. Features of a syndrome are a heterogeneous population that can be split into at least two classes, those presenting and those not presenting the syndrome. Syndromes are characterized by a specific mixture of signs and symptoms which increase in prevalence, from less to more severe classes. So far, the null hypothesis of homogeneity - signs and symptoms of frailty cannot identify at least two classes - has been tested using Latent Class Analysis (LCA) on the five dichotomized components of PMF (unintentional weight loss, exhaustion, weakness, slowness, and low physical activity). The aim of this study is to investigate further the construct validity of frailty as a syndrome using the extension offered by Factor Mixture Models (FMM). METHODS: LCA on dichotomized scores and FMM on continuous scores were conducted to test homogeneity on the five PMF components in a sample of 1643 community-dwelling older adults living in Québec, Canada (FRéLE). RESULTS: With dichotomized LCA, three frailty classes were found: robust, prefrail and frail, and the hypothesis of homogeneity was rejected. However, in FMM, frailty was better represented as a continuous variable than as latent heterogeneous classes. Thus, the PMF measurement model of frailty did not meet the features of a syndrome in this study. CONCLUSION: Using the FRéLE cohort, the PMF measurement model validity is questioned. Valid measurement of a syndrome depends on an understanding of its etiological factors and pathophysiological processes, and on a modelling of how the measured components are linked to these processes. Without these features, assessing frailty in a clinical setting may not improve patient health. Research on frailty should address these issues before promoting its use in clinical settings.


Assuntos
Fragilidade , Idoso , Canadá , Estudos Transversais , Idoso Fragilizado , Fragilidade/diagnóstico , Fragilidade/epidemiologia , Avaliação Geriátrica , Humanos , Fenótipo , Quebeque , Síndrome
17.
Indian J Public Health ; 64(Supplement): S128-S131, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32496242

RESUMO

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted (at the time of writing) in over 3.3 million cases and 233,000 deaths globally and ~33,000 cases and ~1,100 deaths in India. The mainstay of the diagnosis is a reverse-transcription polymerase chain reaction assay to detect SARS-CoV-2 RNA. The accurate diagnosis is contingent on appropriate specimen choice, time of collection, and assay employed. In this commentary, we highlight the role of laboratory diagnostic tests used in the different stages of India's COVID-19 pandemic response.


Assuntos
Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Anticorpos Antivirais/metabolismo , Betacoronavirus , COVID-19 , Infecções por Coronavirus/epidemiologia , Reações Falso-Negativas , Humanos , Imunoensaio , Índia/epidemiologia , Pandemias , Pneumonia Viral/epidemiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SARS-CoV-2 , Cultura de Vírus
18.
Anal Chem ; 91(17): 11355-11361, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31359753

RESUMO

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) using a (CO2)6k+ gas cluster ion beam (GCIB) was used to analyze Escherichia coli mutants previously identified as having impaired plasmid transfer capability related to the spread of antibiotic resistance. The subset of mutants selected were expected to result in changes in the bacterial envelope composition through the deletion of genes encoding for FabF, DapF, and Lpp, where the surface sensitivity of ToF-SIMS can be most useful. Analysis of arrays of spotted bacteria allowed changes in the lipid composition of the bacteria to be elucidated using multivariate analysis and confirmed through imaging of individual ion signals. Significant changes in chemical composition were observed, including a surprising loss of cyclopropanated fatty acids in the fabF mutant where FabF is associated with the elongation of FA(16:1) to FA(18:1) and not cyclopropane formation. The ability of the GCIB to generate increased higher mass signals from biological samples allowed intact lipid A (m/z 1796) to be detected on the bacteria and, despite a 40 keV impact energy, depth profiled through the bacterial envelope along with other high mass ions including species at m/z 1820 and 2428, attributed to ECACYC, that were only observed below the surface of the bacteria and were notably absent in the depth profile of the lpp mutant. The analysis provides new insights into the action of the specific pathways targeted in this study and paves the way for whole new avenues for the characterization of intact molecules within the bacterial envelope.


Assuntos
Membrana Celular/química , Escherichia coli/genética , Plasmídeos/metabolismo , Espectrometria de Massa de Íon Secundário/métodos , Acetiltransferases/genética , Isomerases de Aminoácido/genética , Proteínas da Membrana Bacteriana Externa/genética , Resistência Microbiana a Medicamentos , Escherichia coli/química , Escherichia coli/enzimologia , Escherichia coli/ultraestrutura , Proteínas de Escherichia coli/genética , Ácido Graxo Sintase Tipo II/genética , Ácidos Graxos/análise , Lipídeo A/análise , Lipídeos/análise , Lipoproteínas/genética , Proteínas Mutantes
19.
J Clin Ethics ; 30(2): 128-130, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31188789

RESUMO

In the context of all of the discussion about "Fletcherian" ethics consultation, we're including this description of ethics consultation for clarity and in deference to the work of John C. Fletcher. It's reprinted from the third edition of Fletcher's Introduction to Clinical Ethics.


Assuntos
Consultoria Ética , Humanos
20.
Circulation ; 135(25): 2534-2555, 2017 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-28630267

RESUMO

Peripheral artery disease affects >200 million people worldwide and is associated with significant limb and cardiovascular morbidity and mortality. Limb revascularization is recommended to improve function and quality of life for symptomatic patients with peripheral artery disease with intermittent claudication who have not responded to medical treatment. For patients with critical limb ischemia, the goals of revascularization are to relieve pain, help wound healing, and prevent limb loss. The baseline risk of cardiovascular and limb-related events demonstrated among patients with stable peripheral artery disease is elevated after revascularization and related to atherothrombosis and restenosis. Both of these processes involve platelet activation and the coagulation cascade, forming the basis for the use of antiplatelet and anticoagulant therapies to optimize procedural success and reduce postprocedural cardiovascular risk. Unfortunately, few high-quality, randomized data to support use of these therapies after peripheral artery disease revascularization exist, and much of the rationale for the use of antiplatelet agents after endovascular peripheral revascularization is extrapolated from percutaneous coronary intervention literature. Consequently, guideline recommendations for antithrombotic therapy after lower limb revascularization are inconsistent and not always evidence-based. In this context, the purpose of this structured review is to assess the available randomized data for antithrombotic therapy after peripheral arterial revascularization, with a focus on clinical trial design issues that may affect interpretation of study results, and highlight areas that require further investigation.


Assuntos
Consenso , Gerenciamento Clínico , Fibrinolíticos/administração & dosagem , Doença Arterial Periférica/tratamento farmacológico , Sociedades Médicas/normas , Ensaios Clínicos como Assunto/métodos , Humanos , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/fisiopatologia
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