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1.
Med Eng Phys ; 121: 104067, 2023 11.
Article in English | MEDLINE | ID: mdl-37985031

ABSTRACT

Mitral valve function depends on its complex geometry and tissue health, with alterations in shape and tissue response affecting the long-term restorarion of function. Previous computational frameworks for biomechanical assessment are mostly based on patient-specific geometries; however, these are not flexible enough to yield a variety of models and assess mitral closure for individually tuned morphological parameters or material property representations. This study details the finite element approach implemented in our previously developed toolbox to assess mitral valve biomechanics and showcases its flexibility through the generation and biomechanical evaluation of different models. A healthy valve geometry was generated and its computational predictions for biomechanics validated against data in the literature. Moreover, two mitral valve models including geometric alterations associated with disease were generated and analysed. The healthy mitral valve model yielded biomechanical predictions in terms of valve closure dynamics, leaflet stresses and papillary muscle and chordae forces comparable to previous computational and experimental studies. Mitral valve function was compromised in geometries representing disease, expressed by the presence of regurgitating areas, elevated stress on the leaflets and unbalanced subvalvular apparatus forces. This showcases the flexibility of the toolbox concerning the generation of a range of mitral valve models with varying geometric definitions and material properties and the evaluation of their biomechanics.


Subject(s)
Mitral Valve Insufficiency , Mitral Valve , Humans , Mitral Valve/physiology , Biomechanical Phenomena , Finite Element Analysis , Papillary Muscles/physiology , Models, Cardiovascular
2.
Vaccines (Basel) ; 11(10)2023 Oct 05.
Article in English | MEDLINE | ID: mdl-37896969

ABSTRACT

Dogs with visceral leishmaniasis play a key role in the transmission cycle of Leishmania infantum to humans in the urban environment. There is a consensus regarding the importance of developing a vaccine to control this disease. Despite many efforts to develop a protective vaccine against CVL, the ones currently available, Leish-tec® and LetiFend®, have limited effectiveness. This is due, in part, to the complexity of the immune response of the naturally infected dogs against the parasite and the complexity of the parasite transmission cycle. Thus, strategies, such as the development of a transmission-blocking vaccines (TBVs) already being applied to other vector-borne diseases like malaria and dengue, would be an attractive alternative to control leishmaniasis. TBVs induce the production of antibodies in the vertebrate host, which can inhibit parasite development in the vector and/or interfere with aspects of vector biology, leading to an interruption of parasite transmission. To date, there are few TBV studies for CVL and other leishmaniasis forms. However, the few studies that exist show promising results, thus justifying the further development of this approach.

3.
Am J Lifestyle Med ; 17(3): 336-354, 2023.
Article in English | MEDLINE | ID: mdl-37304744

ABSTRACT

Introduction: The relevance of lifestyle medicine in diabetes treatment is now incorporated in clinical practice guidelines but finding an exemplar for the creation of a Lifestyle Medicine Program (LMP) is a difficult task. Aim: To use Lifedoc Health (LDH) as a LMP exemplar by describing their multidisciplinary team (MDT) approach to diabetes care along with tactics to address sustainability challenges. Results: The LDH model facilitates early activation of patients with diabetes and other cardiometabolic risk factors, MDT approaches, and protocols/policies that are able to overcome barriers to equitable healthcare in the community. Specific programmatic targets are clinical outcomes, effective dissemination, economic viability, and sustainability. Infrastructure centers on patient-driven problem-based visits, shared medical appointments, telemedicine, and patient tracking. Further discussions on program conceptualization and operationalization are provided. Conclusion: Even though strategic plans for LMPs that specialize in diabetes care are well represented in the literature, implementation protocols, and performance metrics are lacking. The LDH experience provides a starting point for those healthcare professionals interested in translating ideas into action.

4.
Ticks Tick Borne Dis ; 13(1): 101828, 2022 01.
Article in English | MEDLINE | ID: mdl-34628330

ABSTRACT

Rhipicephalus microplus, popularly known as the cattle tick, is the most important tick of livestock as it is responsible for significant economic losses. The use of chemical acaricides is still the most widely used control method despite its known disadvantages. Vaccination would be a safe alternative for the control of R. microplus and holds advantages over the use of chemical acaricides as it is environmental-friendly and leaves no residues in meat or milk. Two vaccines based on the Bm86 protein were commercialized, TickGARD® and Gavac®, with varying reported efficacies in different countries. The use of other vaccines, such as Tick Vac®, Go-Tick®, and Bovimune Ixovac® have been restricted to some countries. Several other proteins have been analyzed as possible antigens for more effective vaccines against R. microplus, including peptidases, serine proteinase inhibitors, glutathione S-transferases, metalloproteases, and ribosomal proteins, with efficacies ranging from 14% to 96%. Nonetheless, more research is needed to develop safe and efficient tick vaccines, such as the evaluation of the efficacy of antigens against other tick species to verify cross-reactivity and inclusion of additional antigens to promote the blocking of the infection and spreading of tick-borne diseases. This review summarizes the discoveries of candidate antigens for R. microplus tick vaccines as well as the methods used to test their efficacy.


Subject(s)
Cattle Diseases , Rhipicephalus , Tick Infestations , Vaccines , Animals , Antigens , Cattle , Cattle Diseases/prevention & control , Tick Infestations/prevention & control , Tick Infestations/veterinary , Vaccination
5.
PLoS One ; 16(11): e0259196, 2021.
Article in English | MEDLINE | ID: mdl-34731193

ABSTRACT

Coronary bifurcations are prone to atherosclerotic plaque growth, experiencing regions of reduced wall shear stress (WSS) and increased platelet adhesion. This study compares effects across different rheological approaches on hemodynamics, combined with a shear stress exposure history model of platelets within a stenosed porcine bifurcation. Simulations used both single/multiphase blood models to determine which approach best predicts phenomena associated with atherosclerosis and atherothrombosis. A novel Lagrangian platelet tracking model was used to evaluate residence time and shear history of platelets indicating likely regions of thrombus formation. Results show a decrease in area of regions with pathologically low time-averaged WSS with the use of multiphase models, particularly in a stenotic bifurcation. Significant non-Newtonian effects were observed due to low-shear and varying hematocrit levels found on the outer walls of the bifurcation and distal to the stenosis. Platelet residence time increased 11% in the stenosed artery, with exposure times to low-shear sufficient for red blood cell aggregation (>1.5 s). increasing the risk of thrombosis. This shows stenotic artery hemodynamics are inherently non-Newtonian and multiphase, with variations in hematocrit (0.163-0.617) and elevated vorticity distal to stenosis (+15%) impairing the function of the endothelium via reduced time-averaged WSS regions, rheological properties and platelet activation/adhesion.


Subject(s)
Coronary Stenosis/blood , Coronary Stenosis/physiopathology , Coronary Vessels/physiopathology , Animals , Hemodynamics , Models, Cardiovascular , Platelet Activation , Rheology , Stress, Mechanical , Swine
6.
Comput Biol Med ; 135: 104628, 2021 08.
Article in English | MEDLINE | ID: mdl-34246162

ABSTRACT

The mitral valve is a complex anatomical structure, whose shape is key to several traits of its function and disease, being crucial for the success of surgical repair and implantation of medical devices. The aim of this study was to develop a parametric, scalable, and clinically useful model of the mitral valve, enabling the biomechanical evaluation of mitral repair techniques through finite element simulations. MATLAB was used to parameterize the valve: the annular boundary was sampled from a porcine mitral valve mesh model and landmark points and relevant boundaries were selected for the parameterization of leaflets using polynomial fitting. Several geometric parameters describing the annulus, leaflet shape and papillary muscle position were implemented and used to scale the model according to patient dimensions. The developed model, available as a toolbox, allows for the generation of a population of models using patient-specific dimensions obtained from medical imaging or averaged dimensions evaluated from empirical equations based on the Golden Proportion. The average model developed using this framework accurately represents mitral valve shapes, associated with relative errors reaching less than 10% for annular and leaflet length dimensions, and less than 24% in comparison with clinical data. Moreover, model generation takes less than 5 min of computing time, and the toolbox can account for individual morphological variations and be employed to evaluate mitral valve biomechanics; following further development and validation, it will aid clinicians when choosing the best patient-specific clinical intervention and improve the design process of new medical devices.


Subject(s)
Mitral Valve Insufficiency , Mitral Valve , Animals , Biomechanical Phenomena , Humans , Mitral Valve/diagnostic imaging , Swine
7.
Cureus ; 13(3): e13917, 2021 Mar 16.
Article in English | MEDLINE | ID: mdl-33880269

ABSTRACT

Dysembryoplastic neuroepithelial tumors (DNETs) are benign mixed glioneuronal neoplasms that frequently occur in children and young adults. We present the case of a 17-year-old male who arrived at the hospital following seizure-like activity. A magnetic resonance imaging (MRI) scan showed a 10 x 8 x 10 mm, oval-shaped, non-enhancing, well-defined mass within the right hippocampus. The patient underwent a transcortical approach via the middle temporal gyrus for resection of the mass; histopathological examination demonstrated the presence of round, uniform cells in an extensively myxoid background with diffuse reactivity to glial fibrillary acidic protein (GFAP). DNETs are considered benign, non-recurring lesions. Complete surgical resection is associated with a seizure-free outcome in 80% to 100% of cases.

8.
Cureus ; 13(1): e12759, 2021 Jan 18.
Article in English | MEDLINE | ID: mdl-33614352

ABSTRACT

Proton pump inhibitors (PPIs) marked a before and after in the management of gastric acid-related disorders since their introduction to the market in 1989. Due to a novel, highly effective mechanism of action blocking the last converging step of gastric acid secretion by parietal cells and very few and mostly tolerable side effects, these drugs quickly displaced other pharmacological compounds such as H2 antagonists as the first treatment choice for peptic ulcer disease, gastroesophageal ulcers, Zollinger-Ellison syndrome, nonsteroidal anti-inflammatory drug-associated ulcers, and eradication of Helicobacter pylori, leading to an exponential increase in their prescription up to now. However, widespread PPI use has led to emerging evidence of long-term adverse effects not described previously, including increased risk of kidney, liver, and cardiovascular disease, dementia, enteroendocrine tumors of the gastrointestinal tract, susceptibility to respiratory and gastrointestinal infections, and impaired absorption of nutrients. Although the evidence published thus far has not established strong correlations, it has been relevant enough to raise new questions about PPIs' safety profile and reconsideration of their clinical indications. Hence, the aim of this review is to evaluate the association between PPI use and the risk of serious adverse effects given increasing concerns about the overuse of PPIs in the general population.

9.
PLoS One ; 16(2): e0247438, 2021.
Article in English | MEDLINE | ID: mdl-33630903

ABSTRACT

Central venous catheters are widely used in haemodialysis therapy, having to respect design requirements for appropriate performance. These are placed within the right atrium (RA); however, there is no prior computational study assessing different catheter designs while mimicking their native environment. Here, a computational fluid dynamics model of the RA, based on realistic geometry and transient physiological boundary conditions, was developed and validated. Symmetric, split and step catheter designs were virtually placed in the RA and their performance was evaluated by: assessing their interaction with the RA haemodynamic environment through prediction of flow vorticity and wall shear stress (WSS) magnitudes (1); and quantifying recirculation and tip shear stress (2). Haemodynamic predictions from our RA model showed good agreement with the literature. Catheter placement in the RA increased average vorticity, which could indicate alterations of normal blood flow, and altered WSS magnitudes and distribution, which could indicate changes in tissue mechanical properties. All designs had recirculation and elevated shear stress values, which can induce platelet activation and subsequently thrombosis. The symmetric design, however, had the lowest associated values (best performance), while step design catheters working in reverse mode were associated with worsened performance. Different tip placements also impacted on catheter performance. Our findings suggest that using a realistically anatomical RA model to study catheter performance and interaction with the haemodynamic environment is crucial, and that care needs to be given to correct tip placement within the RA for improved recirculation percentages and diminished shear stress values.


Subject(s)
Blood Flow Velocity/physiology , Catheterization, Central Venous/instrumentation , Heart Atria/physiopathology , Catheters, Indwelling , Central Venous Catheters , Computer Simulation , Equipment Design/instrumentation , Hemodynamics/physiology , Humans , Hydrodynamics , Models, Anatomic , Models, Cardiovascular , Stress, Mechanical
10.
PLoS One ; 15(8): e0236946, 2020.
Article in English | MEDLINE | ID: mdl-32764790

ABSTRACT

Hemodialysis catheters are used to support blood filtration, yet there are multiple fundamentally different approaches to catheter tip design with no clear optimal solution. Side-holes have been shown to increase flow rates and decrease recirculation but have been associated with clotting/increased infection rates. This study investigates the impact of changing the shape, size and number of side-holes on a simple symmetric tip catheter by evaluating the velocity, shear stress and shear rate of inflowing blood. A platelet model is used to examine the residence time and shear history of inflowing platelets. The results show that side-holes improve the theoretical performance of the catheters, reducing the maximum velocity and shear stress occurring at the tip compared to non-side-hole catheters. Increasing the side-hole area improved performance up to a point, past which not all inflow through the hole was captured, and instead a small fraction slowly 'washed-out' through the remainder of the tip resulting in greater residence times and increasing the likelihood of platelet adhesion. An oval shaped hole presents a lower chance of external fibrin formation compared to a circular hole, although this would also be influenced by the catheter material surface topology which is dependent on the manufacturing process. Overall, whilst side-holes may be associated with increased clotting and infection, this can be reduced when side-hole geometry is correctly implemented though; a sufficient area for body diameter (minimising residence time) and utilising angle-cut, oval shaped holes (reducing shear stress and chances of fibrin formation partially occluding holes).


Subject(s)
Catheters , Renal Dialysis/instrumentation , Blood Flow Velocity , Blood Platelets/cytology , Catheters/statistics & numerical data , Computational Biology , Computer Simulation , Equipment Design , Hemodynamics , Humans , Hydrodynamics , Models, Cardiovascular , Platelet Adhesiveness
11.
Cardiovasc Eng Technol ; 11(4): 431-447, 2020 08.
Article in English | MEDLINE | ID: mdl-32519086

ABSTRACT

PURPOSE: Bicuspid aortic valve (BAV) is a congenital heart malformation with phenotypic heterogeneity. There is no prior computational study that assesses the haemodynamic and valve mechanics associated with BAV type 2 against a healthy tricuspid aortic valve (TAV) and other BAV categories. METHODS: A proof-of-concept study incorporating three-dimensional fluid-structure interaction (FSI) models with idealised geometries (one TAV and six BAVs, namely type 0 with lateral and anterior-posterior orientations, type 1 with R-L, N-R and N-L leaflet fusion and type 2) has been developed. Transient physiological boundary conditions have been applied and simulations were run using an Arbitrary Lagrangian-Eulerian formulation. RESULTS: Our results showed the presence of abnormal haemodynamics in the aorta and abnormal valve mechanics: type 0 BAVs yielded the best haemodynamical and mechanical outcomes, but cusp stress distribution varied with valve orifice orientation, which can be linked to different cusp calcification location onset; type 1 BAVs gave rise to similar haemodynamics and valve mechanics, regardless of raphe position, but this position altered the location of abnormal haemodynamic features; finally, type 2 BAV constricted the majority of blood flow, exhibiting the most damaging haemodynamic and mechanical repercussions when compared to other BAV phenotypes. CONCLUSION: The findings of this proof-of-concept work suggest that there are specific differences across haemodynamics and valve mechanics associated with BAV phenotypes, which may be critical to subsequent processes associated with their pathophysiology processes.


Subject(s)
Bicuspid Aortic Valve Disease/physiopathology , Hemodynamics , Models, Cardiovascular , Bicuspid Aortic Valve Disease/diagnostic imaging , Biomechanical Phenomena , Blood Flow Velocity , Computer Simulation , Elastic Modulus , Humans , Phenotype , Proof of Concept Study , Stress, Mechanical
12.
J Clin Nurs ; 29(9-10): 1590-1598, 2020 May.
Article in English | MEDLINE | ID: mdl-32096283

ABSTRACT

AIMS AND OBJECTIVES: To compare and evaluate interobserver (nurses and physicians) agreement for dengue clinical signs and symptoms, including the World Health Organization diagnostic algorithm. BACKGROUND: Agreement of clinical history defines the capacity of the examiner to measure a given clinical parameter in a reproducible and consistent manner, which is prerequisite for diagnosis validity. Nurses play a major role in the triage and care of dengue patients in many countries. STUDY DESIGN: This is a sub-study on interobserver agreement performed as part of a cross-sectional diagnostic accuracy study for acute febrile illness (AFI) using the checklist STARD. METHODS: A previously validated semi-structured sign and symptom standardised questionnaire for AFI was independently administered to 374 patients by physician and nurse pairs. The interobserver agreement was estimated using kappa statistics. RESULTS: For a set of 27 signs and symptoms, we found six interobserver discrepancies (examiner detected red eyes, lethargy, exanthema, dyspnoea, bleeding and myalgia) as identified by regular and moderate kappa indexes. Four signs (patient observed red eyes, cough, diarrhoea and vomiting) and one symptom (earache) had near-perfect agreement. Most signs and symptoms showed substantial agreement. The WHO (Dengue guidelines for diagnosis, treatment, prevention and control: new edition, World Health Organization, 2009) clinical criteria for dengue comprise a group of symptoms known as "pains and aches." Interobserver agreement for abdominal pain, retro-orbital pain and arthralgia exceed that found for headache and myalgia. CONCLUSIONS: During a dengue outbreak, the interobserver agreement for most of the signs and symptoms used to assess AFI was substantial. RELEVANCE TO CLINICAL PRACTICE: This result suggests good potential applicability of the tool by health professionals following training. A well-trained health professional is qualified to apply the standardised questionnaire to evaluate suspected dengue cases during outbreaks.


Subject(s)
Dengue/diagnosis , Observer Variation , Surveys and Questionnaires/standards , Adult , Cross-Sectional Studies , Dengue/physiopathology , Female , Fever/diagnosis , Humans , Male , Middle Aged
13.
Article in English | MEDLINE | ID: mdl-31921703

ABSTRACT

Visceral leishmaniasis (VL), caused by digenetic protozoa of the genus Leishmania, is the most severe form of leishmaniasis. Leishmania infantum is one of the species responsible for VL and the disease caused is considered a zoonosis whose main reservoir is the dog. Canine visceral leishmaniasis (CVL) can lead to the death of the animal if left untreated. Furthermore, the available pharmocologial treatment for CVL presents numerous disadvantages, such as relapses, toxicity, drug resistance, and the fact treated animals continue to be reservoirs when treatment fails to achieve parasitological cure. Moreover, the available VL control methods have not been adequate when it comes to controlling parasite transmission. Advances in immune response knowledge in recent years have led to a better understanding of VL pathogenesis, allowing new treatments to be developed based on immune system activation, often referred to as immunotherapy. In fact, well-defined protocols have been described, ranging from the use of immunomodulators to the use of vaccines. This treatment, which can also be associated with chemotherapy, has been shown to be effective in restoring or inducing an adequate immune response to reduce parasitic burden, leading to clinical improvement. This review focuses on immunotherapy directed at dogs infected by L. infantum, including a literature review of what has already been done in dogs. We also introduce a promising strategy to improve the efficacy of immunotherapy.


Subject(s)
Antigens, Protozoan/therapeutic use , Dog Diseases/therapy , Immunotherapy/methods , Leishmaniasis, Visceral/therapy , Leishmaniasis, Visceral/veterinary , Animals , Antibodies, Protozoan/immunology , Antigens, Protozoan/administration & dosage , Antigens, Protozoan/immunology , Biomarkers , Dog Diseases/immunology , Dog Diseases/parasitology , Dogs , Humans , Immunologic Factors/therapeutic use , Leishmania infantum/immunology , Leishmaniasis, Visceral/immunology , Protozoan Vaccines/therapeutic use , Treatment Outcome
14.
Bioinformatics ; 33(4): 547-548, 2017 02 15.
Article in English | MEDLINE | ID: mdl-27797761

ABSTRACT

Summary: The move of computational genomics workflows to Cloud Computing platforms is associated with a new level of integration and interoperability that challenges existing data representation formats. The Variant Calling Format (VCF) is in a particularly sensitive position in that regard, with both clinical and consumer-facing analysis tools relying on this self-contained description of genomic variation in Next Generation Sequencing (NGS) results. In this report we identify an isomorphic map between VCF and the reference Resource Description Framework. RDF is advanced by the World Wide Web Consortium (W3C) to enable representations of linked data that are both distributed and discoverable. The resulting ability to decompose VCF reports of genomic variation without loss of context addresses the need to modularize and govern NGS pipelines for Precision Medicine. Specifically, it provides the flexibility (i.e. the indexing) needed to support the wide variety of clinical scenarios and patient-facing governance where only part of the VCF data is fitting. Availability and Implementation: Software libraries with a claim to be both domain-facing and consumer-facing have to pass the test of portability across the variety of devices that those consumers in fact adopt. That is, ideally the implementation should itself take place within the space defined by web technologies. Consequently, the isomorphic mapping function was implemented in JavaScript, and was tested in a variety of environments and devices, client and server side alike. These range from web browsers in mobile phones to the most popular micro service platform, NodeJS. The code is publicly available at https://github.com/ibl/VCFr , with a live deployment at: http://ibl.github.io/VCFr/ . Contact: jonas.almeida@stonybrookmedicine.edu.


Subject(s)
Genetic Variation , Genome , High-Throughput Nucleotide Sequencing/methods , Sequence Analysis, DNA/methods , Software , Genomics/methods , Humans , Information Storage and Retrieval , Semantics
15.
BMC Infect Dis ; 16: 37, 2016 Jan 29.
Article in English | MEDLINE | ID: mdl-26822788

ABSTRACT

BACKGROUND: Early diagnosis of dengue infection is important for decision-making and timely implementation of therapeutic measures. Although rapid NS1 assays have been used for dengue diagnosis since 2008, their performance in DENV-4 cases has not yet been fully assessed. METHODS: We evaluated the accuracy of NS1 Bioeasy™ immunochromatographic strip test and of three clinical criteria for dengue diagnosis. Patients presenting at an emergency care center within 72 h of an acute febrile illness during the 2013 DENV-4 epidemic in Rio de Janeiro were consecutively enrolled for clinical and laboratory evaluation. We classified patients as suspected dengue or not according to three clinical criteria: WHO 2009, WHO 1997, and INI-FIOCRUZ. Dengue diagnosis was defined by RNA detection using RT-PCR and the negative cases were negative for all dengue serotypes and also Platelia™ NS1 ELISA. We obtained accuracy indices for NS1 Bioeasy™ alone and in combination with the clinical criteria. RESULTS: RT-PCR for DENV-4 was positive in 148 out of 325 patients. Positive likelihood ratio, sensitivity, and specificity of NS1 Bioeasy™ with WHO 2009, WHO 1997, and INI-FIOCRUZ criteria were 22.6 (95% CI 7.2-70.6), 40.6% (95% CI 32.3-49.3), and 98.2% (95% CI 94.9-99.6); 18.3 (95% CI 6.8-49.2), 44.2 (95% CI 35.8-52.9), 97.6 (95% CI 94.0-99.3); 26.2 (95% CI 6.5-106.5), 29.7 (95% CI 22.4-37.8), 98.9 (95% CI 96.0-99.9), respectively. WHO 1997 clinical criteria presented high sensitivity to rule out disease, but extremely low specificity. INI-FIOCRUZ had moderate sensitivity and specificity, and could target a group to a more specific test. CONCLUSIONS: Although the large rates of false negative results using NS1 Bioeasy™ rapid test advise against its use for triaging (rule out) purposes in DENV-4 epidemics, it could be used as a confirmatory tool in a bedside algorithm.


Subject(s)
Dengue Virus/metabolism , Dengue/diagnosis , Adult , Brazil/epidemiology , Dengue/epidemiology , Dengue/virology , Dengue Virus/genetics , Dengue Virus/isolation & purification , Early Diagnosis , Enzyme-Linked Immunosorbent Assay , Epidemics , Female , Humans , Male , Middle Aged , Point-of-Care Systems , RNA, Viral/analysis , Reagent Kits, Diagnostic , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity , Serogroup , Viral Nonstructural Proteins/analysis , Viral Nonstructural Proteins/immunology
16.
Chemosphere ; 127: 214-21, 2015 May.
Article in English | MEDLINE | ID: mdl-25732633

ABSTRACT

The presence and formation of methylmercury (MMHg), a highly toxic form of Hg, in mangrove ecosystems is poorly studied. Therefore the aim of this study was to evaluate mercury methylation potentials in sediment, litter and root samples (Avicennia shaueriana and Spartina alterniflora) from different regions of a mangrove ecosystem, as well as the influence of salinity on methylation. Sediment was sampled under different depths and in mangrove regions with different plant covers and salinities. All samples were incubated with (203)Hg and MM(203)Hg was extracted and measured by liquid scintillation. MMHg was formed in all samples and sites tested including plant roots and litter. Higher Hg methylation was found in the superficial fraction of sediments (0.47-7.82%). Infralittoral sandy sediment had low MMHg formation (0.44-1.61%). Sediment under Rhizophora mangle had lower MMHg formation (0.018-2.23%) than under A. shaueriana (0.2-4.63%) and Laguncularia racemosa (0.08-7.82). MMHg formation in sediment tended to increase with salinity but the differences were not significant. Therefore, MMHg formation occurs in different sites of mangrove ecosystems and may be an important threat that requires further study.


Subject(s)
Avicennia/chemistry , Ecosystem , Geologic Sediments/chemistry , Methylmercury Compounds/analysis , Poaceae/chemistry , Avicennia/growth & development , Brazil , Mercury/analysis , Methylation , Plant Leaves/chemistry , Plant Roots/chemistry , Plant Roots/growth & development , Poaceae/growth & development , Rhizosphere , Salinity
17.
Integr Biol (Camb) ; 6(11): 1088-99, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25212181

ABSTRACT

The bacterial two-component system (TCS) regulates genes that are crucial for virulence in several pathogens. One of such TCS, the PhoPR system, consisting of a transmembrane sensory histidine kinase protein (PhoR) and an intracellular response regulator protein (PhoP), has been reported to have a major role in mycobacterial pathogenesis. We knocked out the phoP in C. pseudotuberculosis, the causal organism of caseous lymphadenitis (CLA), and using a combination of in vitro and in vivo mouse system, we showed for the first time, that the PhoP of C. pseudotuberculosis plays an important role in the virulence and pathogenicity of this bacterium. Furthermore, we modeled the PhoP of C. pseudotuberculosis and our docking results showed that several natural compounds including Rhein, an anthraquinone from Rheum undulatum, and some drug-like molecules may target PhoP to inhibit the TCS of C. pseudotuberculosis, and therefore may facilitate a remarkable attenuation of bacterial pathogenicity being the CLA. Experiments are currently underway to validate these in silico docking results.


Subject(s)
Bacterial Proteins/immunology , Corynebacterium Infections/immunology , Corynebacterium pseudotuberculosis/pathogenicity , Signal Transduction/immunology , Animals , Anthraquinones/pharmacology , Bacterial Proteins/antagonists & inhibitors , Bacterial Proteins/genetics , Biological Assay , Cell Line , Cell Survival/immunology , Corynebacterium Infections/genetics , Corynebacterium pseudotuberculosis/genetics , Corynebacterium pseudotuberculosis/immunology , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Macrophages , Mice , Mice, Inbred BALB C , Molecular Docking Simulation , Polymerase Chain Reaction , Sequence Deletion/genetics , Sequence Deletion/immunology , Virulence
18.
Int J Data Min Bioinform ; 10(3): 329-56, 2014.
Article in English | MEDLINE | ID: mdl-25946867

ABSTRACT

The whole set of human imprinted genes, termed imprintome, is here analysed by means of a reasonable, valid application of the Semantic Web and Linked Data approaches to a few structured datasets in order to provide a comprehensive collection of imprinted genes in the human genome. Thus, we have stored, organised, filtered, and analysed massive amounts of existing data on human imprinted genes towards compiling, structuring and linking data to comprise a sharing resource for genome and epigenome interrogated studies. Our datasets of linked data are the actual research outcome of this human imprintome analysis because as genomics become more and more data intensive, due to huge amounts of biological data, so does our needs for more structured data to be easier mined and shared. We present the resulting first version of the Linked Human Imprintome as a project within Linked Open Data (LOD) initiative (http://lod-cloud.net/) through Data Hub (http:// thedatahub.org/en/dataset/a-draft-version-of-the-linked-human-imprintome).


Subject(s)
Computational Biology/methods , Genomic Imprinting , Genomics/methods , Access to Information , Algorithms , CpG Islands , Databases, Factual , Epigenomics , Gene Expression Profiling , Genome, Human , Humans , Pseudogenes , Semantics , Software
19.
Ecotoxicol Environ Saf ; 96: 124-30, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23829936

ABSTRACT

Mercury is a toxic pollutant and spreads to several compartments in the environment. Previous in-vitro studies showed that roots of aquatic macrophytes are sites of methylmercury formation, performed mainly by sulfate-reducing bacteria (SRB). The objective of this study was to observe MMHg formation and distribution among filtered water (0.2µm), suspended and settled particles and macrophyte roots during seventeen days, in (203)Hg- spiked mesocosms with and without live Eichhornia crassipes whole plants and a SRB inhibitor. Root samples were also incubated in-vitro for comparison of MM(203)Hg formation under in-vitro and in-vivo conditions. To evaluate the effect of SRB inhibition by sodium molybdate on total heterotrophic activity, the latter was measured by (3)H-leucine uptake. Inhibition of Hg methylation by sodium molybdate decreased with time in mesocosms. MMHg averaged 10, 12.4 and 0.23 percent of total (203)Hg present in filtered water, suspended particles and roots respectively. In vitro MMHg formation in roots averaged 5.54 percent of total added (203)Hg, with a clearer SRB inhibition effect than in mesocosms. Though significant, MMHg formation in roots from in-vivo mesocosms was one order of magnitude lower than previously found in in-vitro incubations of roots alone.


Subject(s)
Eichhornia/metabolism , Mercury/metabolism , Bacteria/metabolism , Eichhornia/chemistry , Eichhornia/drug effects , Enzyme Inhibitors/pharmacology , Mercury/analysis , Methylation/drug effects , Methylmercury Compounds/pharmacology , Molybdenum/pharmacology , Plant Roots/chemistry , Plant Roots/drug effects , Plant Roots/metabolism
20.
Nucleic Acids Res ; 41(15): 7387-400, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23761445

ABSTRACT

Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector-human and vector-parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi.


Subject(s)
Anopheles/genetics , Genome, Insect , Insect Vectors/genetics , Animals , Anopheles/classification , Brazil , Chromosomes, Insect/genetics , DNA Transposable Elements , Evolution, Molecular , Female , Genetic Variation , Host-Parasite Interactions , Insect Proteins/genetics , Insect Vectors/classification , Insecticide Resistance , Insecticides/pharmacology , Malaria/parasitology , Male , Molecular Sequence Annotation , Phylogeny , Synteny , Transcriptome
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