Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 213
Filter
Add more filters

Publication year range
1.
PLoS Biol ; 20(8): e3001769, 2022 08.
Article in English | MEDLINE | ID: mdl-35998195

ABSTRACT

We propose a novel, non-discriminatory classification of monkeypox virus diversity. Together with the World Health Organization, we named three clades (I, IIa and IIb) in order of detection. Within IIb, the cause of the current global outbreak, we identified multiple lineages (A.1, A.2, A.1.1 and B.1) to support real-time genomic surveillance.


Subject(s)
Monkeypox virus , Mpox (monkeypox) , Disease Outbreaks , Genomics , Humans , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Monkeypox virus/genetics
2.
Nature ; 572(7768): 260-264, 2019 08.
Article in English | MEDLINE | ID: mdl-31341286

ABSTRACT

In humans, the adaptive immune system uses the exchange of information between cells to detect and eliminate foreign or damaged cells; however, the removal of unwanted cells does not always require an adaptive immune system1,2. For example, cell selection in Drosophila uses a cell selection mechanism based on 'fitness fingerprints', which allow it to delay ageing3, prevent developmental malformations3,4 and replace old tissues during regeneration5. At the molecular level, these fitness fingerprints consist of combinations of Flower membrane proteins3,4,6. Proteins that indicate reduced fitness are called Flower-Lose, because they are expressed in cells marked to be eliminated6. However, the presence of Flower-Lose isoforms at a cell's membrane does not always lead to elimination, because if neighbouring cells have similar levels of Lose proteins, the cell will not be killed4,6,7. Humans could benefit from the capability to recognize unfit cells, because accumulation of damaged but viable cells during development and ageing causes organ dysfunction and disease8-17. However, in Drosophila this mechanism is hijacked by premalignant cells to gain a competitive growth advantage18. This would be undesirable for humans because it might make tumours more aggressive19-21. It is unknown whether a similar mechanism of cell-fitness comparison is present in humans. Here we show that two human Flower isoforms (hFWE1 and hFWE3) behave as Flower-Lose proteins, whereas the other two isoforms (hFWE2 and hFWE4) behave as Flower-Win proteins. The latter give cells a competitive advantage over cells expressing Lose isoforms, but Lose-expressing cells are not eliminated if their neighbours express similar levels of Lose isoforms; these proteins therefore act as fitness fingerprints. Moreover, human cancer cells show increased Win isoform expression and proliferate in the presence of Lose-expressing stroma, which confers a competitive growth advantage on the cancer cells. Inhibition of the expression of Flower proteins reduces tumour growth and metastasis, and induces sensitivity to chemotherapy. Our results show that ancient mechanisms of cell recognition and selection are active in humans and affect oncogenic growth.


Subject(s)
Calcium Channels/metabolism , Cell Proliferation , Drosophila Proteins/metabolism , Neoplasms/pathology , Protein Isoforms/metabolism , Animals , Calcium Channels/genetics , Cell Line, Tumor , Cell Transformation, Neoplastic/genetics , Drosophila melanogaster , Female , Gene Knockdown Techniques , Humans , Male , Neoplasm Metastasis , Neoplasms/drug therapy , Protein Isoforms/genetics
3.
Eur J Clin Microbiol Infect Dis ; 43(4): 791-795, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38332396

ABSTRACT

We report for the first time in Portugal a serotype c Haemophilus influenzae isolated from an adult, with HIV-1 infection. Whole-genome sequencing characterized the isolate as clonal complex ST-7, albeit with a novel MLST (ST2754) due to a unique atpG profile. Integration of this genome with other available H. influenzae serotype c genomes from PubMLST revealed its overall genetic distinctiveness, with the closest related isolate being identified in France in 2020. This surveillance study, involving collaboration among hospitals and reference laboratory, successfully contributed to the identification and characterization of this rare serotype.


Subject(s)
Haemophilus Infections , Haemophilus influenzae , Adult , Humans , Serogroup , Haemophilus influenzae/genetics , Multilocus Sequence Typing , Haemophilus Infections/epidemiology , Haemophilus Infections/microbiology , Portugal/epidemiology , Serotyping
4.
Emerg Infect Dis ; 29(3): 569-575, 2023 03.
Article in English | MEDLINE | ID: mdl-36737101

ABSTRACT

We estimated comparative primary and booster vaccine effectiveness (VE) of SARS-CoV-2 Omicron BA.5 and BA.2 lineages against infection and disease progression. During April-June 2022, we implemented a case-case and cohort study and classified lineages using whole-genome sequencing or spike gene target failure. For the case-case study, we estimated the adjusted odds ratios (aORs) of vaccination using a logistic regression. For the cohort study, we estimated VE against disease progression using a penalized logistic regression. We observed no reduced VE for primary (aOR 1.07 [95% CI 0.93-1.23]) or booster (aOR 0.96 [95% CI 0.84-1.09]) vaccination against BA.5 infection. Among BA.5 case-patients, booster VE against progression to hospitalization was lower than that among BA.2 case-patients (VE 77% [95% CI 49%-90%] vs. VE 93% [95% CI 86%-97%]). Although booster vaccination is less effective against BA.5 than against BA.2, it offers substantial protection against progression from BA.5 infection to severe disease.


Subject(s)
COVID-19 Vaccines , COVID-19 , Humans , Portugal , Cohort Studies , SARS-CoV-2 , Disease Progression
5.
Acta Neuropathol ; 145(1): 113-126, 2023 01.
Article in English | MEDLINE | ID: mdl-36198883

ABSTRACT

Hereditary transthyretin amyloidosis (ATTRv) is a systemic disease caused by the accumulation of misfolded transthyretin (TTR). It usually presents with an adult-onset progressive axonal peripheral neuropathy and cardiomyopathy. In the central nervous system (CNS), variant TTR is produced by the choroid plexus and accumulates in the leptomeninges. CNS symptoms have been increasingly recognized in this population, including transient focal neurological episodes and stroke, particularly in patients with the V30M mutation and longstanding disease. The prevalence, pathophysiology, and progression of CNS involvement remain to be clarified. The present work explores if there is a recognizable sequence of CNS TTR deposition in ATTRv. We studied the topographical and severity distribution of TTR deposition in 16 patients with ATTRv, aged 27-69 years and with a mean disease duration of 10.9 years (range: 3-29). Our results suggest that CNS pathological involvement in V30M ATTRv occurs early in the disease course, probably starting in pre-symptomatic phases, and follows a distinct sequence. Leptomeninges and subarachnoid meningeal vessels are affected earlier, then followed by perforating cortical vessels and subpial deposition, and finally by deposition in the subependymal and basal ganglia vessels near the ependymal lining. Brainstem and spinal cord show early and severe involvement, with amyloid subpial deposition already seen in initial stages. Despite massive superficial amyloid deposition, no parenchymal deposition outside subpial or subependymal regions was found. Additionally, vascular lesions or superficial cortical siderosis were not frequent. Future studies with more patients from different populations and TTR mutations will be important to confirm these findings. Defining stages of TTR pathology in the CNS may be useful to better understand pathogenic mechanisms leading to symptoms and to interpret neuroimaging biomarkers.


Subject(s)
Amyloid Neuropathies, Familial , Nervous System Diseases , Adult , Humans , Prealbumin/genetics , Prealbumin/metabolism , Amyloid Neuropathies, Familial/genetics , Amyloid Neuropathies, Familial/diagnosis , Amyloid Neuropathies, Familial/pathology , Nervous System Diseases/pathology , Mutation/genetics , Brain/pathology
6.
Int J Mol Sci ; 24(3)2023 Feb 02.
Article in English | MEDLINE | ID: mdl-36769230

ABSTRACT

The application of whole genome sequencing of Mycobacterium tuberculosis directly on clinical samples has been investigated as a means to avoid the time-consuming need for culture isolation that can lead to a potential prolonged suboptimal antibiotic treatment. We aimed to provide a proof-of-concept regarding the application of the molecular capture of M. tuberculosis genomes directly from positive sputum samples as an approach for epidemiological and drug susceptibility predictions. Smear-positive sputum samples (n = 100) were subjected to the SureSelectXT HS Target Enrichment protocol (Agilent Technologies, Santa Clara, CA, USA) and whole-genome sequencing analysis. A higher number of reads on target were obtained for higher smear grades samples (i.e., 3+ followed by 2+). Moreover, 37 out of 100 samples showed ≥90% of the reference genome covered with at least 10-fold depth of coverage (27, 9, and 1 samples were 3+, 2+, and 1+, respectively). Regarding drug-resistance/susceptibility prediction, for 42 samples, ≥90% of the >9000 hits that are surveyed by TB-profiler were detected. Our results demonstrated that M. tuberculosis genome capture and sequencing directly from clinical samples constitute a potential valid backup approach for phylogenetic inferences and resistance prediction, essentially in settings when culture is not routinely performed or for samples that fail to grow.


Subject(s)
Mycobacterium tuberculosis , Tuberculosis , Humans , Mycobacterium tuberculosis/genetics , Antitubercular Agents/pharmacology , Antitubercular Agents/therapeutic use , Phylogeny , Whole Genome Sequencing , Sputum/microbiology , Tuberculosis/drug therapy , Tuberculosis/epidemiology , Tuberculosis/microbiology , Microbial Sensitivity Tests
7.
Int J Mol Sci ; 24(20)2023 Oct 20.
Article in English | MEDLINE | ID: mdl-37895081

ABSTRACT

The Mycobacterium abscessus complex (MABC) is an emerging, difficult to treat, multidrug-resistant nontuberculous mycobacteria responsible for a wide spectrum of infections and associated with an increasing number of cases worldwide. Dominant circulating clones (DCCs) of MABC have been genetically identified as groups of strains associated with higher prevalence, higher levels of antimicrobial resistance, and worse clinical outcomes. To date, little is known about the genomic characteristics of MABC species circulating in Portugal. Here, we examined the genetic diversity and antimicrobial resistance profiles of 30 MABC strains isolated between 2014 and 2022 in Portugal. The genetic diversity of circulating MABC strains was assessed through a gene-by-gene approach (wgMLST), allowing their subspecies differentiation and the classification of isolates into DCCs. Antimicrobial resistance profiles were defined using phenotypic, molecular, and genomic approaches. The majority of isolates were resistant to at least two antimicrobials, although a poor correlation between phenotype and genotype data was observed. Portuguese genomes were highly diverse, and data suggest the existence of MABC lineages with potential international circulation or cross-border transmission. This study highlights the genetic diversity and antimicrobial resistance profile of circulating MABC isolates in Portugal while representing the first step towards the implementation of a genomic-based surveillance system for MABC at the Portuguese NIH.


Subject(s)
Anti-Infective Agents , Mycobacterium Infections, Nontuberculous , Mycobacterium abscessus , Humans , Mycobacterium abscessus/genetics , Portugal , Mycobacterium Infections, Nontuberculous/drug therapy , Nontuberculous Mycobacteria , Anti-Infective Agents/therapeutic use , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Microbial Sensitivity Tests
8.
Entropy (Basel) ; 25(6)2023 Jun 15.
Article in English | MEDLINE | ID: mdl-37372288

ABSTRACT

In this work, we explore the formalism of the irreversible thermodynamics of open systems and the possibility of gravitationally generated particle production in modified gravity. More specifically, we consider the scalar-tensor representation of f(R,T) gravity, in which the matter energy-momentum tensor is not conserved due to a nonminimal curvature-matter coupling. In the context of the irreversible thermodynamics of open systems, this non-conservation of the energy-momentum tensor can be interpreted as an irreversible flow of energy from the gravitational sector to the matter sector, which, in general, could result in particle creation. We obtain and discuss the expressions for the particle creation rate, the creation pressure, and the entropy and temperature evolutions. Applied together with the modified field equations of scalar-tensor f(R,T) gravity, the thermodynamics of open systems lead to a generalization of the ΛCDM cosmological paradigm, in which the particle creation rate and pressure are considered effectively as components of the cosmological fluid energy-momentum tensor. Thus, generally, modified theories of gravity in which these two quantities do not vanish provide a macroscopic phenomenological description of particle production in the cosmological fluid filling the Universe and also lead to the possibility of cosmological models that start from empty conditions and gradually build up matter and entropy.

9.
J Am Chem Soc ; 143(39): 16147-16153, 2021 10 06.
Article in English | MEDLINE | ID: mdl-34559527

ABSTRACT

Many DNA replication and DNA repair enzymes have been found to carry [4Fe4S] clusters. The major leading strand polymerase, DNA polymerase ε (Pol ε) from Saccharomyces cerevisiae, was recently reported to have a [4Fe4S] cluster located within the catalytic domain of the largest subunit, Pol2. Here the redox characteristics of the [4Fe4S] cluster in the context of that domain, Pol2CORE, are explored using DNA electrochemistry, and the effects of oxidation and rereduction on polymerase activity are examined. The exonuclease deficient variant D290A/E292A, Pol2COREexo-, was used to limit DNA degradation. While no redox signal is apparent for Pol2COREexo- on DNA-modified electrodes, a large cathodic signal centered at -140 mV vs NHE is observed after bulk oxidation. A double cysteine to serine mutant (C665S/C668S) of Pol2COREexo-, which lacks the [4Fe4S] cluster, shows no similar redox signal upon oxidation. Significantly, protein oxidation yields a sharp decrease in polymerization, while rereduction restores activity almost to the level of untreated enzyme. Moreover, the addition of reduced EndoIII, a bacterial DNA repair enzyme containing [4Fe4S]2+, to oxidized Pol2COREexo- bound to its DNA substrate also significantly restores polymerase activity. In contrast, parallel experiments with EndoIIIY82A, a variant of EndoIII, defective in DNA charge transport (CT), does not show restoration of activity of Pol2COREexo-. We propose a model in which EndoIII bound to the DNA duplex may shuttle electrons through DNA to the DNA-bound oxidized Pol2COREexo- via DNA CT and that this DNA CT signaling offers a means to modulate the redox state and replication by Pol ε.


Subject(s)
DNA Polymerase II/metabolism , Iron-Sulfur Proteins/metabolism , Saccharomyces cerevisiae Proteins/chemistry , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/enzymology , DNA Polymerase II/genetics , Iron-Sulfur Proteins/chemistry , Oxidation-Reduction , Signal Transduction
10.
Sex Transm Dis ; 47(11): e54-e56, 2020 11.
Article in English | MEDLINE | ID: mdl-32530860

ABSTRACT

We report a multidrug-resistant Neisseria gonorrhoeae exhibiting resistance to ceftriaxone and cefixime, isolated in Portugal in 2019. Whole-genome sequencing was performed for typing and identification of genetic determinants of antimicrobial resistance. Because of its antimicrobial susceptibility profile, awareness should be raised for the circulation of this strain.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cefixime/pharmacology , Ceftriaxone/pharmacology , Gonorrhea/drug therapy , Neisseria gonorrhoeae/drug effects , Adult , Anti-Bacterial Agents/therapeutic use , Drug Resistance, Multiple, Bacterial , Gonorrhea/diagnosis , Humans , Male , Microbial Sensitivity Tests , Neisseria gonorrhoeae/genetics , Neisseria gonorrhoeae/isolation & purification , Portugal
11.
Eur J Clin Microbiol Infect Dis ; 39(9): 1761-1770, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32494956

ABSTRACT

Neisseria gonorrhoeae antimicrobial resistance (AMR) and gonorrhea disease burden remain major public health concerns worldwide. To contribute to the supranational demands to monitor and manage the spread of antimicrobial-resistant N. gonorrhoeae, the Portuguese NIH promoted the creation of the National Laboratory Network for Neisseria gonorrhoeae Collection (PTGonoNet). The present study reports the N. gonorrhoeae major AMR trends observed from 2003 up to 2018. All isolates described in the present study constitute the opportunistic ongoing N. gonorrhoeae isolate collection supported by the National Reference Laboratory for Sexually Transmitted Infections of the Portuguese NIH, enrolling strains isolated in 35 different public and private laboratories. Minimum inhibitory concentrations were determined using E-tests for azithromycin, benzylpenicillin, cefixime, ceftriaxone, ciprofloxacin, gentamicin, spectinomycin and tetracycline. Molecular typing was determined using NG-MAST. AMR data of 2596 country-spread isolates show that 87.67% of all N. gonorrhoeae isolates presented decreased susceptibility to at least one antimicrobial. A continuous decreased susceptibility and resistance to penicillin, tetracycline and ciprofloxacin can be observed along the years. However, no decreased susceptibility to cephalosporins was observed until 2018, while for azithromycin, this was always low. The most common observed NG-MAST genogroups were G1407, G7445, G225, G2, and G1034. This study evidences the advantages of a nationwide collection of isolates and of centralized AMR testing to respond to supranational (EURO-GASP) requirements while providing unprecedented data on AMR in the context of 15 years of surveillance.


Subject(s)
Anti-Bacterial Agents/pharmacology , Gonorrhea/epidemiology , Neisseria gonorrhoeae/isolation & purification , Adolescent , Adult , Child , Demography , Drug Resistance, Bacterial , Female , Gonorrhea/drug therapy , Gonorrhea/microbiology , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Molecular Epidemiology , Neisseria gonorrhoeae/drug effects , Neisseria gonorrhoeae/genetics , Portugal/epidemiology , Specimen Handling , Young Adult
12.
J Clin Microbiol ; 57(8)2019 08.
Article in English | MEDLINE | ID: mdl-31167846

ABSTRACT

Quality management and independent assessment of high-throughput sequencing-based virus diagnostics have not yet been established as a mandatory approach for ensuring comparable results. The sensitivity and specificity of viral high-throughput sequence data analysis are highly affected by bioinformatics processing using publicly available and custom tools and databases and thus differ widely between individuals and institutions. Here we present the results of the COMPARE [Collaborative Management Platform for Detection and Analyses of (Re-)emerging and Foodborne Outbreaks in Europe] in silico virus proficiency test. An artificial, simulated in silico data set of Illumina HiSeq sequences was provided to 13 different European institutes for bioinformatics analysis to identify viral pathogens in high-throughput sequence data. Comparison of the participants' analyses shows that the use of different tools, programs, and databases for bioinformatics analyses can impact the correct identification of viral sequences from a simple data set. The identification of slightly mutated and highly divergent virus genomes has been shown to be most challenging. Furthermore, the interpretation of the results, together with a fictitious case report, by the participants showed that in addition to the bioinformatics analysis, the virological evaluation of the results can be important in clinical settings. External quality assessment and proficiency testing should become an important part of validating high-throughput sequencing-based virus diagnostics and could improve the harmonization, comparability, and reproducibility of results. There is a need for the establishment of international proficiency testing, like that established for conventional laboratory tests such as PCR, for bioinformatics pipelines and the interpretation of such results.


Subject(s)
Computational Biology/methods , Computer Simulation , High-Throughput Nucleotide Sequencing/standards , Laboratory Proficiency Testing/statistics & numerical data , Sequence Analysis, DNA/standards , Viruses/genetics , Data Analysis , Europe , Genome, Viral , High-Throughput Nucleotide Sequencing/methods , Humans , Intersectoral Collaboration , Laboratory Proficiency Testing/organization & administration , Reproducibility of Results , Sequence Analysis, DNA/statistics & numerical data , Viruses/pathogenicity
13.
Muscle Nerve ; 59(1): 137-141, 2019 01.
Article in English | MEDLINE | ID: mdl-30025162

ABSTRACT

INTRODUCTION: Mutations in the EXOSC3 gene are responsible for type 1 pontocerebellar hypoplasia, an autosomal recessive congenital disorder characterized by cerebellar atrophy, developmental delay, and anterior horn motor neuron degeneration. Muscle biopsies of these patients often show characteristics resembling classic spinal muscle atrophy, but to date, no distinct features have been identified. METHODS: Clinical data and muscle biopsy findings of 3 unrelated patients with EXOSC3 mutations are described. RESULTS: All patients presented as a severe congenital cognitive and neuromuscular phenotype with short survival, harboring the same point mutation (c.92G>C; p.Gly31Ala). Muscle biopsies consistently showed variable degrees of sarcomeric disorganization with myofibrillar remnants, Z-line thickening, and small nemaline bodies. CONCLUSIONS: In this uniform genetic cohort of patients with EXOSC3 mutations, sarcomeric disruption and rod structures were prominent features of muscle biopsies. In the context of neonatal hypotonia, ultrastructural studies might provide early clues for the diagnosis of EXOSC3-related pontocerebellar hypoplasia. Muscle Nerve 59:137-141, 2019.


Subject(s)
Exosome Multienzyme Ribonuclease Complex/genetics , Muscle, Skeletal/pathology , Mutation/genetics , Olivopontocerebellar Atrophies/genetics , Olivopontocerebellar Atrophies/pathology , RNA-Binding Proteins/genetics , Sarcoma/pathology , Biopsy , Child, Preschool , Cohort Studies , Female , Humans , Infant, Newborn , Male , Muscle, Skeletal/ultrastructure , Myopathies, Nemaline , Sarcoma/ultrastructure
14.
Inorg Chem ; 58(21): 14522-14531, 2019 Nov 04.
Article in English | MEDLINE | ID: mdl-31550141

ABSTRACT

Herein we report the synthesis, characterization, and cellular internalization properties of two visible-light active luminescent Mn-based photoCORMs. The enhanced membrane permeability of the photoactive Mn carbonyl complex (photoCORM) derived from a designed lipophilic ligand namely, [Mn(CO)3(Imdansyl)(L1)](CF3SO3) (1) (where L1 = a diazabutadiene-based ligand containing two highly lipophilic adamantyl motifs, Imdansyl = dansylimidazole) promoted rapid internalization within human colorectal adenocarcinoma (HT-29) cells compared to [Mn(CO)3(Imdansyl)(L2)](CF3SO3) (2) (where L2 = a diazabutadiene ligand bearing two hydrophilic 1,3,5-triazaadamantyl group). Colocalization experiments using membrane stain indicate different extents of localization of the two CO complexes within the cellular matrix. Visible-light triggered CO release from the lipophilic photoCORM induced caspase-3/7 activation on HT-29 cells, which was detected using confocal microscopy. The rapid accumulation of the lipophilic photoCORM 1 in the cellular membrane resulted in more efficient CO-induced cell death compared to the hydrophilic analogue 2.


Subject(s)
Coordination Complexes/pharmacology , Light , Luminescent Agents/pharmacology , Cell Death/drug effects , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , Crystallography, X-Ray , HT29 Cells , Humans , Hydrophobic and Hydrophilic Interactions , Ligands , Luminescent Agents/chemical synthesis , Luminescent Agents/chemistry , Models, Molecular , Neoplasms/drug therapy , Solubility
15.
Bioconjug Chem ; 29(5): 1677-1689, 2018 05 16.
Article in English | MEDLINE | ID: mdl-29635917

ABSTRACT

The uptake and transport of dietary antioxidants remains the most important setback for their application in therapy. To overcome the limitations, a PEGylated-based platform was developed to improve the delivery properties of two dietary hydroxycinnamic (HCA) antioxidants-caffeic and ferulic acids. The antioxidant properties of the new polymer-antioxidant conjugates (PEGAntiOxs), prepared by linking poly(ethylene glycol) (PEG) to the cinnamic acids by a one-step Knovenagel condensation reaction, were evaluated. PEGAntiOxs present a higher lipophilicity than the parent compounds (caffeic and ferulic acids) and similar, or higher, antioxidant properties. PEGAntiOxs were not cytotoxic at the tested concentrations in SH-SY5Y, Caco-2, and hCMEC/D3 cells. By contrast, cytotoxic effects in hCMEC/D3 and SH-SY5Y cells were observed, at 50 and 100 µM, for caffeic and ferulic acids. PEGAntiOxs operate as antioxidants against several oxidative stress-cellular inducers in a neuronal cell-based model, and were able to inhibit glycoprotein-P in Caco-2 cells. PEGAntiOxs can cross hCMEC/D3 monolayer cells, a model of the blood-brain barrier (BBB) endothelial membrane. In summary, PEGAntiOxs are valid antioxidant prototypes that can uphold the antioxidant properties of HCAs, reduce their cytotoxicity, and improve their BBB permeability. PEGAntiOxs can be used in the near future as drug candidates to prevent or slow oxidative stress associated with neurodegenerative diseases.


Subject(s)
Antioxidants/pharmacology , Antioxidants/pharmacokinetics , Blood-Brain Barrier/metabolism , Cinnamates/pharmacology , Cinnamates/pharmacokinetics , Polyethylene Glycols/pharmacology , Polyethylene Glycols/pharmacokinetics , Antioxidants/chemistry , Caco-2 Cells , Capillary Permeability , Cell Line , Cinnamates/chemistry , Humans , Oxidative Stress/drug effects , Polyethylene Glycols/chemistry
16.
Inorg Chem ; 57(11): 6692-6701, 2018 Jun 04.
Article in English | MEDLINE | ID: mdl-29775296

ABSTRACT

Microbial invasion and colonization of the skin and underlying soft tissues are among the most common types of infections, becoming increasingly prevalent in hospital settings. Systemic antibiotic chemotherapies are now extremely limited due to emergence of drug-resistant Gram-positive and multidrug-resistant Gram-negative bacterial strains. Topical administration of antimicrobials provides an effective route for the treatment of skin and soft tissue infections (SSTIs). Therefore, the development of new and effective materials for the delivery of these agents is of paramount importance. Silver is a broad-spectrum antibiotic used for the treatment and prevention of infections since ancient times. However, the high reactivity of silver cation (Ag+) makes its incorporation into delivery materials quite challenging. Herein we report a novel soft agar hydrogel composite for the delivery of Ag+ into infected wound sites. This material incorporates a Ag(I) complex [Ag2(DSX)2(NO3)2] (1; DSX = 5-(dimethylamino)- N, N-bis(pyridin-2-ylmethyl) naphthalene-1-sulfonamide) that exhibits a change in fluorescence upon Ag+ release and qualitatively indicates the end point of silver delivery. The antibacterial efficacy of the material was tested against several bacterial strains in an SSTI model. The complex 1-agar composite proved effective at eradicating the pathogens responsible for the majority of SSTIs. The theranostic (therapeutic/diagnostic) properties coupled with its stability, softness, ease of application, and removal make this material an attractive silver-delivery vehicle for the treatment and prevention of SSTIs.


Subject(s)
Agar/pharmacology , Anti-Bacterial Agents/pharmacology , Coordination Complexes/pharmacology , Fluorescent Dyes/pharmacology , Silver/chemistry , Agar/chemical synthesis , Agar/chemistry , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , Drug Carriers , Drug Resistance, Multiple, Bacterial , Drug Stability , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , Gram-Negative Aerobic Rods and Cocci/drug effects , Hydrogels , Ligands , Microbial Sensitivity Tests , Prodrugs/chemical synthesis , Prodrugs/chemistry , Prodrugs/pharmacology , Skin Diseases, Bacterial/drug therapy , Soft Tissue Infections/drug therapy , Staphylococcus aureus/drug effects , Surgical Wound Infection/drug therapy , Theranostic Nanomedicine
18.
Microb Pathog ; 104: 296-302, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28161356

ABSTRACT

Syphilis is the sexually transmitted disease caused by Treponema pallidum, a pathogen highly adapted to the human host. As a multistage disease, syphilis presents distinct clinical manifestations that pose different implications for diagnosis. Nevertheless, the inherent factors leading to diverse disease progressions are still unknown. We aimed to assess the association between treponemal loads and dissimilar disease outcomes, to better understand syphilis. We retrospectively analyzed 309 DNA samples distinct anatomic sites associated with particular syphilis manifestations. All samples had previously tested positive by a PCR-based diagnostic kit. An absolute quantitative real-time PCR procedure was used to precisely quantify the number of treponemal and human cells to determine T. pallidum loads in each sample. In general, lesion exudates presented the highest T. pallidum loads in contrast with blood-derived samples. Within the latter, a higher dispersion of T. pallidum quantities was observed for secondary syphilis. T. pallidum was detected in substantial amounts in 37 samples of seronegative individuals and in 13 cases considered as syphilis-treated. No association was found between treponemal loads and serological results or HIV status. This study suggests a scenario where syphilis may be characterized by: i) heterogeneous and high treponemal loads in primary syphilis, regardless of the anatomic site, reflecting dissimilar duration of chancres development and resolution; ii) high dispersion of bacterial concentrations in secondary syphilis, potentially suggesting replication capability of T. pallidum while in the bloodstream; and iii) bacterial evasiveness, either to the host immune system or antibiotic treatment, while remaining hidden in privileged niches. This work highlights the importance of using molecular approaches to study uncultivable human pathogens, such as T. pallidum, in the infection process.


Subject(s)
Bacterial Load , Syphilis/microbiology , Syphilis/pathology , Treponema pallidum/isolation & purification , Cross-Sectional Studies , Female , Humans , Male , Portugal , Real-Time Polymerase Chain Reaction , Retrospective Studies , Serologic Tests , Treponema pallidum/genetics
19.
Soft Matter ; 13(48): 9246-9258, 2017 Dec 13.
Article in English | MEDLINE | ID: mdl-29199755

ABSTRACT

We use the Dynamic Density-Functional Formalism and the Fundamental Measure Theory as applied to a fluid of parallel hard squares to study the dynamics of heterogeneous growth of non-uniform phases with columnar and crystalline symmetries. The hard squares are (i) confined between soft repulsive walls with a square symmetry, or (ii) exposed to external potentials that mimic the presence of obstacles with circular, square, rectangular or triangular symmetries. For the first case the final equilibrium profile of a well commensurated cavity consists of a crystal phase with highly localized particles in concentric square layers at the nodes of a slightly deformed square lattice. We characterize the growth dynamics of the crystal phase by quantifying the interlayer and intralayer fluxes and the non-monotonicity of the former, the saturation time, and other dynamical quantities. The interlayer fluxes are much more monotonic in time, and dominant for poorly commensurated cavities, while the opposite is true for well commensurated cells: although smaller, the time evolution of interlayer fluxes is much more complex, presenting strongly damped oscillations which dramatically increase the saturation time. We also study how the geometry of the obstacle affects the symmetry of the final equilibrium non-uniform phase (columnar vs. crystal). For obstacles with fourfold symmetry, (circular and square) the crystal is more stable, while the columnar phase is stabilized for obstacles without this symmetry (rectangular or triangular). We find that, in general, density waves of columnar symmetry grow from the obstacle. However, additional particle localization along the wavefronts gives rise to a crystalline structure which is conserved for circular and square obstacles, but destroyed for the other two obstacles where columnar symmetry is restored.

20.
J Chem Phys ; 146(13): 134503, 2017 Apr 07.
Article in English | MEDLINE | ID: mdl-28390379

ABSTRACT

Using transfer operator and fundamental measure theories, we examine the structural and thermodynamic properties of hard rectangles confined between two parallel hard walls. The side lengths of the rectangle (L and D, L>D) and the pore width (H) are chosen such that a maximum of two layers is allowed to form when the long sides of the rectangles are parallel to the wall, while only one layer is possible in case the rectangles are perpendicular to the wall. We observe three different structures: (i) at low density, the rectangles align mainly parallel to the wall, (ii) at intermediate or high density, two fluid layers form in which the rectangles are parallel to the wall, and (iii) a dense single fluid layer with rectangles aligned mainly perpendicular to the wall. The transition between these structures is smooth without any non-analytic behaviour in the thermodynamic quantities; however, the fraction of particles perpendicular (or parallel) to the wall can exhibit a relatively sudden change if L is close to H. In this case, interestingly, even three different structures can be observed with increasing density.

SELECTION OF CITATIONS
SEARCH DETAIL