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This work focuses on the δ receptor (DOR), a G protein-coupled receptor (GPCR) belonging to the opioid receptor group. DOR is expressed in numerous tissues, particularly within the nervous system. Our study explores computationally the receptor's interactions with various ligands, including opiates and opioid peptides. It elucidates how these interactions influence the δ receptor response, relevant in a wide range of health and pathological processes. Thus, our investigation aims to explore the significance of DOR as an incoming drug target for pain relief and neurodegenerative diseases and as a source for novel opioid non-narcotic analgesic alternatives. We analyze the receptor's structural properties and interactions using Molecular Dynamics (MD) simulations and Gaussian-accelerated MD across different functional states. To thoroughly assess the primary differences in the structural and conformational ensembles across our different simulated systems, we initiated our study with 1 µs of conventional Molecular Dynamics. The strategy was chosen to encompass the full activation cycle of GPCRs, as activation processes typically occur within this microsecond range. Following the cMD, we extended our study with an additional 100 ns of Gaussian accelerated Molecular Dynamics (GaMD) to enhance the sampling of conformational states. This simulation approach allowed us to capture a comprehensive range of dynamic interactions and conformational changes that are crucial for GPCR activation as influenced by different ligands. Our study includes comparing agonist and antagonist complexes to uncover the collective patterns of their functional states, regarding activation, blocking, and inactivation of DOR, starting from experimental data. In addition, we also explored interactions between agonist and antagonist molecules from opiate and opioid classifications to establish robust structure-activity relationships. These interactions have been systematically quantified using a Quantitative Structure-Activity Relationships (QSAR) model. This research significantly contributes to our understanding of this significant pharmacological target, which is emerging as an attractive subject for drug development.
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Simulação de Dinâmica Molecular , Receptores Opioides delta , Receptores Opioides delta/metabolismo , Receptores Opioides delta/química , Humanos , Ligantes , Analgésicos Opioides/farmacologia , Analgésicos Opioides/química , Ligação Proteica , Conformação ProteicaRESUMO
Bats are important natural reservoir hosts of a diverse range of viruses that can be transmitted to humans and have been suggested to play an important role in the Zika virus (ZIKV) transmission cycle. However, the exact role of these animals as reservoirs for flaviviruses is still controversial. To further expand our understanding of the role of bats in the ZIKV transmission cycle in Latin America, we carried out an experimental infection in wild-caught Artibeus lituratus bats and sampled several free-living neotropical bats across three countries of the region. Experimental ZIKV infection was performed in wild-caught adult bats (4 females and 5 males). The most relevant findings were hemorrhages in the bladder, stomach and patagium. Significant histological findings included inflammatory infiltrate consisting of a predominance of neutrophils and lymphocytes, in addition to degeneration in the reproductive tract of males and females. This suggests that bat reproduction might be at some level affected by ZIKV. Leukopenia was also observed in some inoculated animals. Hemorrhages, genital alterations, and leukopenia are suggested to be caused by ZIKV; however, since these were wild-caught bats, we cannot exclude other agents. Detection of ZIKV by qPCR was observed at low concentrations in only two urine samples in two inoculated animals. All other animals and tissues tested were negative. Finally, no virus-neutralizing antibodies were found in any animal. To determine ZIKV infection in nature, the blood of a total of 2056 bats was sampled for ZIKV detection by qPCR. Most of the sampled individuals belonged to the genus Pteronotus sp. (23%), followed by the species Carollia sp. (17%), Anoura sp. (14%), and Molossus sp. (13.7%). No sample of any tested species was positive for ZIKV by qPCR. These results together suggest that bats are not efficient amplifiers or reservoirs of ZIKV and may not have an important role in ZIKV transmission dynamics.
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Quirópteros , Infecção por Zika virus , Zika virus , Animais , Feminino , Masculino , Costa Rica/epidemiologia , Guiana Francesa/epidemiologia , Peru/epidemiologia , Zika virus/genética , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/veterinária , Infecção por Zika virus/diagnósticoRESUMO
CC Chemokine receptor 5 (CCR5), a member of the Superfamily of G Protein-Coupled Receptors (GPCRs), is an important effector in multiple physiopathological processes such as inflammatory and infectious entities, including central nervous system neuroinflammatory diseases such as Alzheimer's disease, recovery from nervous injuries, and in the HIV-AIDS infective processes. Thus, CCR5 is an attractive target for pharmacological modulation. Since maraviroc was described as a CCR5 ligand that modifies the HIV-AIDS progression, multiple efforts have been developed to describe the functionality of the receptor. In this work, we characterized key structural features of the CCR5 receptor employing extensive atomistic molecular dynamics (MD) in its apo form and in complex with an endogenous agonist, the chemokine CCL5/RANTES, an HIV entry inhibitor, the partial inverse agonist maraviroc, and the experimental antagonists Compound 21 and 34, aiming to elucidate the structural features and mechanistic processes that constitute its functional states, contributing with structural details and a general understanding of this relevant system.
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Inibidores da Fusão de HIV , Infecções por HIV , Antagonistas dos Receptores CCR5/farmacologia , Antagonistas dos Receptores CCR5/uso terapêutico , Quimiocina CCL5/farmacologia , Infecções por HIV/tratamento farmacológico , Humanos , Imidazóis , Ligantes , Maraviroc/uso terapêutico , Receptores CCR5 , Sulfonamidas , TiofenosRESUMO
The CX3C chemokine receptor 1 (CX3CR1), a member of the class A of G Protein-Coupled Receptors (GPCR) superfamily, and its ligand fractalkine constitute an important biochemical axis that influence many cellular pathways involving homeostatic and inflammatory processes. They participate in the activation, chemotaxis and recruitment of multiple immunological cells such as microglia, macrophages and monocytes, and play a critical role in neuroinflammatory conditions such as Alzheimer's disease and multiple sclerosis, in the recovery from central nervous system injuries, in several chronic, peripheral inflammatory entities and in some infective processes including HIV-AIDS. In this work we present the study of the CX3CR1 receptor employing extensive atomistic Molecular Dynamics (MD) simulations with the aim to characterize the conformational ensemble of the receptor in the presence of its antagonist and agonist ligands. We analyzed the receptor conformational changes and described interactions within its key regions and the bounded ligands to identify their notable differences. Finally, we classify the features that would allow the identification of patterns that characterize a functional state to contribute to the understanding of the complexity of the GPCR superfamily.
Assuntos
Quimiocina CX3CL1 , Quimiotaxia , Receptor 1 de Quimiocina CX3C/metabolismo , Quimiocina CX3CL1/metabolismo , Quimiotaxia/fisiologia , Ligantes , Conformação MolecularRESUMO
Schizophrenia is a severe neuropsychiatric disorder that deteriorates perception, affection, and cognitive mental functions. The current treatments are mainly focused on the dopamine system, but the so-named dopamine hypothesis of schizophrenia fails to explain all the symptoms. Previous studies have shown that there is a reciprocal relationship between muscarinic acetylcholine receptors and dopamine receptor function. Some muscarinic ligands show antidopaminergic activity, and therefore, they should have some antipsychotic efficacy. In this work, conceptual density functional theory is employed to analyze the properties of acetylcholine's agonists, partial agonists, or antagonists. The aim is to establish a classification of the antipsychotic-like or pro-psychotic activities of these molecules based on the electron-donor and electron-acceptor properties. Most of the agonists and antagonists are better electron donors and worse electron acceptors than partial agonists. We found that acetylcholine antagonists that clinically promote psychotic symptoms are good electron-donor molecules, and acetylcholine agonists that clinically relieve symptoms of psychosis are good electron donors. These results represent a further advance on the road to understanding the charge-transfer properties of drugs used as possible treatments for schizophrenia.
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Antipsicóticos , Esquizofrenia , Antipsicóticos/farmacologia , Antipsicóticos/uso terapêutico , Colinérgicos/uso terapêutico , Elétrons , Humanos , Ligantes , Esquizofrenia/tratamento farmacológicoRESUMO
Dopamine is an important neurotransmitter that plays a key role in a wide range of both locomotive and cognitive functions in humans. Disturbances on the dopaminergic system cause, among others, psychosis, Parkinson's disease and Huntington's disease. Antipsychotics are drugs that interact primarily with the dopamine receptors and are thus important for the control of psychosis and related disorders. These drugs function as agonists or antagonists and are classified as such in the literature. However, there is still much to learn about the underlying mechanism of action of these drugs. The goal of this investigation is to analyze the intrinsic chemical reactivity, more specifically, the electron donor-acceptor capacity of 217 molecules used as dopaminergic substances, particularly focusing on drugs used to treat psychosis. We analyzed 86 molecules categorized as agonists and 131 molecules classified as antagonists, applying Density Functional Theory calculations. Results show that most of the agonists are electron donors, as is dopamine, whereas most of the antagonists are electron acceptors. Therefore, a new characterization based on the electron transfer capacity is proposed in this study. This new classification can guide the clinical decision-making process based on the physiopathological knowledge of the dopaminergic diseases.
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Dopaminérgicos/farmacologia , Desenho de Fármacos , Doença de Huntington/tratamento farmacológico , Doença de Parkinson/tratamento farmacológico , Transtornos Psicóticos/tratamento farmacológico , Dopaminérgicos/uso terapêutico , HumanosRESUMO
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
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Bartonella spp. have been identified in many bat species worldwide, including the zoonotic species, Candidatus Bartonella mayotimonensis. The common vampire bat (Desmodus rotundus) preys preferentially on livestock in Latin America and is frequently infected with Bartonella spp. To determine the potential role of D. rotundus in transmitting Bartonella to livestock, common vampire bats and bat-bitten domestic ruminants from Mexico were tested for Bartonella infection by blood culture or conventional PCR. Furthermore, to explore the possibility of bite transmission during blood feeding, saliva swabs from 35 D. rotundus known to be either Bartonella bacteremic (Nâ¯=â¯17) or blood culture negative (Nâ¯=â¯18) were tested by PCR to detect the presence of Bartonella DNA. Twenty (17.1%) of 117 sheep and 16 (34.8%) of 46 cattle were Bartonella bacteremic by PCR testing. However, none of them were infected with Bartonella strains previously isolated from vampire bats and none of the 35 D. rotundus saliva swabs tested were PCR positive for Bartonella. All but two animals among those which were Bartonella culture and/or PCR positive, were infected with either B. bovis (cattle) or B. melophagi (sheep). Two sheep were infected by a possible new species, Candidatus Bartonella ovis, being phylogenetically closer to B. bovis than B. melophagi. This study does not support the role of D. rotundus as a reservoir of Bartonella species infecting livestock, which could be transmitted via bite and blood feeding and therefore suggest limited risk of zoonotic transmission of Bartonella from common vampire bats to humans.
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Infecções por Bartonella/veterinária , Bartonella/isolamento & purificação , Bovinos/microbiologia , Quirópteros/microbiologia , DNA Bacteriano/análise , Reservatórios de Doenças/veterinária , Saliva/microbiologia , Ovinos/microbiologia , Animais , Animais Domésticos/microbiologia , Bartonella/genética , Infecções por Bartonella/epidemiologia , Infecções por Bartonella/transmissão , Mordeduras e Picadas/microbiologia , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/transmissão , Quirópteros/fisiologia , DNA Bacteriano/isolamento & purificação , Reservatórios de Doenças/microbiologia , Variação Genética , México/epidemiologia , Filogenia , Reação em Cadeia da Polimerase , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/microbiologia , Doenças dos Ovinos/transmissãoRESUMO
Strong correlation effects emerge from light-matter interactions in coupled resonator arrays, such as the Mott-insulator to superfluid phase transition of atom-photon excitations. We demonstrate that the quenched dynamics of a finite-sized complex array of coupled resonators induces a first-order like phase transition. The latter is accompanied by domain nucleation that can be used to manipulate the photonic transport properties of the simulated superfluid phase; this in turn leads to an empirical scaling law. This universal behavior emerges from the light-matter interaction and the topology of the array. The validity of our results over a wide range of complex architectures might lead to a promising device for use in scaled quantum simulations.
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Bartonellae are emerging blood-borne bacteria that have been recovered from a wide range of mammalian species and arthropod vectors around the world. Bats are now recognized as a potential wildlife reservoir for a diverse number of Bartonella species, including the zoonotic Candidatus B. mayotimonensis. These bat-borne Bartonella species have also been detected in the obligate ectoparasites of bats, such as blood-feeding flies, which could transmit these bacteria within bat populations. To better understand this potential for transmission, we investigated the relatedness between Bartonella detected or isolated from bat hosts sampled in Mexico and their ectoparasites. Bartonella spp. were identified in bat flies collected on two bat species, with the highest prevalence in Trichobius parasiticus and Strebla wiedemanni collected from common vampire bats (Desmodus rotundus). When comparing Bartonella sequences from a fragment of the citrate synthase gene (gltA), vector-associated strains were diverse and generally close to, but distinct from, those recovered from their bacteremic bat hosts in Mexico. Complete Bartonella sequence concordance was observed in only one bat-vector pair. The diversity of Bartonella strains in bat flies reflects the frequent host switch by bat flies, as they usually do not live permanently on their bat host. It may also suggest a possible endosymbiotic relationship with these vectors for some of the Bartonella species carried by bat flies, whereas others could have a mammalian host.
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Infecções por Bartonella/veterinária , Bartonella/isolamento & purificação , Quirópteros/parasitologia , Dípteros/microbiologia , Reservatórios de Doenças/parasitologia , Animais , Bartonella/genética , Infecções por Bartonella/epidemiologia , Infecções por Bartonella/microbiologia , Quirópteros/microbiologia , Dípteros/classificação , Reservatórios de Doenças/microbiologia , Variação Genética , Humanos , México/epidemiologia , Filogenia , Prevalência , ZoonosesRESUMO
Rabies DNA vaccines based on full-length glycoprotein (G) induce virus neutralizing antibody (VNA) responses and protect against the virus challenge. Although conformational epitopes of G are the main target of VNAs, some studies have shown that a polypeptide linear epitope G5 is also able to induce VNAs. However, a G5 DNA vaccine has not been explored. While multiple doses of DNA vaccines are required in order to confer a protective immune response, this could be overcome by the inclusion of C3d-P28, a molecular adjuvant is know to improve the antibody response in several anti-viral vaccine models. To induce and enhance the immune response against rabies in mice, we evaluated two DNA vaccines based on the linear epitope G5 of Rabies Virus (RABV) glycoprotein (pVaxG5 vaccine) and another vaccine consisting of G5 fused to the molecular adjuvant C3d-P28 (pVaxF1 vaccine). VNA responses were measured in mice immunized with both vaccines. The VNA levels from the group immunized with pVaxG5 decreased gradually, while those from the group vaccinated with pVaxF1 remained high throughout the experimental study. After challenge with 22 LD50 of the Challenge Virus Strain (CVS), the survival rate of mice immunized with pVaxG5 and pVaxF1 was increased by 27% and 50% respectively, in comparison to the PBS group. Furthermore, the in vitro proliferation of anti-rabies specific spleen CD4+ and CD8+ T cells from mice immunized with pVaxF1 was observed. Collectively, these results suggest that the linear G5 epitope is a potential candidate vaccine. Furthermore, the addition of a C3d-P28 adjuvant contributed to enhanced protection, the sustained production of VNAs, and a specific T-cell proliferative response.
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Adjuvantes Imunológicos/administração & dosagem , Imunidade Humoral , Vacina Antirrábica/imunologia , Raiva/prevenção & controle , Vacinas de DNA/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Proliferação de Células , Modelos Animais de Doenças , Epitopos/imunologia , Feminino , Camundongos Endogâmicos BALB C , Vacina Antirrábica/administração & dosagem , Análise de Sobrevida , Vacinas de DNA/administração & dosagemRESUMO
Blood-feeding arthropods play a major role in the transmission of several flaviviruses, which represent an important problem for human health. Currently, dengue is one of the most important arboviral emerging diseases worldwide. Furthermore, some previous studies have reported the presence of viral nucleic acids and antibodies against dengue virus (DENV) in wild animals. Our knowledge of the role played by wildlife reservoirs in the sylvatic transmission and maintenance of DENV remains limited. Our objective was to screen blood-feeding ectoparasites (bat flies) and their common vampire bat (Desmodus rotundus) hosts, for flaviviruses in Hidalgo, Mexico. We detected Flavivirus sequences in 38 pools of ectoparasites (Diptera: Streblidae, Strebla wiedemanni and Trichobius parasiticus) and 8 tissue samples of D. rotundus by RT-PCR and semi-nested PCR using FlaviPF1S, FlaviPR2bis, and FlaviPF3S primers specific for NS5, a gene highly conserved among flaviviruses. Phylogenetic inference analysis performed using the maximum likelihood algorithm implemented in PhyML showed that six sequences clustered with DENV (bootstrap value = 53.5%). Although this study supports other reports of DENV detection in bats and arthropods other than Aedes mosquitoes, the role of these ectoparasitic flies and of hematophagous bats in the epidemiology of DENV still warrants further investigation.
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Quirópteros/parasitologia , Vírus da Dengue/isolamento & purificação , Dípteros/virologia , Miíase/veterinária , Animais , Vírus da Dengue/genética , Reservatórios de Doenças/veterinária , México , Miíase/epidemiologia , FilogeniaRESUMO
Recently, the presence of antibodies and dengue virus (DV) RNA in neotropical wild mammals, including Desmodus rotundus, was reported. In a previous study, DV was also found in a high percentage (39.6%) of ectoparasitic hematophagous dipters specifics of these hematophagous bats. In order to verify the susceptibility of these ectoparasites to DV, in this work experimental infections with VD2 of organs explants of Strebla wiedemanni and of Melophagus ovinus were performed using C6/36 cells as control. Viral titers (UFP/mL) were determined at 0, 48 and 96 hrs pi. Infected organs were observed by electron microscopy and under the confocal microscopy indirect immunofluorescence (IIF) using specific conjugates against DV. The infected organs of both species of ectoparasites replicated DV at titers similar to those obtained with the C6/36 cell line (≥106 UFP/mL). Electron microscopy and IIF showed DV replication in the digestive tract, tracheoles, reproductive organs of males but not in females, and milk glands (MG) of both species. In the fatty bodies of the MG of M. ovinus, zones with a high affinity for the DV were observed. In this work the susceptibility of S. wiedemanni and M. ovinus to DV was demonstrated and consequently the probable role of this ectoparasites as wild reservoirs of DV.
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Vírus da Dengue/fisiologia , Dípteros/virologia , Reservatórios de Doenças/parasitologia , Replicação Viral , Animais , Ectoparasitoses/parasitologia , Feminino , Masculino , Especificidade de Órgãos , Fatores SexuaisRESUMO
Se realizó la caracterización molecular de los genes asociados a la producción de ramnolípidos (RL), en 61 cepas bacterianas de la colección del Laboratorio de Microbiología y Biotecnología Microbiana (LAMYBIM) de la Universidad Nacional Mayor de San Marcos, Perú. Las cepas provenian de entornos peruanos contaminados con hidrocarburos y fueron catalogadas como sobreproductoras de RL(n= 21), productoras de RL (n=20) y no productoras de RL (n= 20). Las 61 cepas fueron identificadas bioquímicamente con el sistema API 20 NE. La identificación molecular se realizó empleando el gen del RNAr 16S. Se encontró que Pseudomonas aeruginosa fue el microorganismo de mayor prevalencia en los estratos sobreproductores y productores de ramnolípidos. Además, se encontraron: Burkholderia cepacea, Pseudomonas fluorescens, Aeromonas hydrophila y Chryseobacterium indologenes. Los microorganismos no productores de ramnolípidos, también fueron caracterizados bioquímicamente. Mediante amplificación de PCR y electroforesis en gel de agarosa, estandarizados por la UNAM, se evidenció que las cepas seleccionadas poseen los genes: rhlA, rhlB, rhlR y rhlC. Para el secuenciamiento de la región génica rhLABR, se seleccionaron cuatros especies: Pseudomonas aeruginosa T2X-2, Pseudomonas aeruginosa IIIT1P2, Pseudomonas aeruginosa 6K-11 y Pseudomonas aeruginosa ATCC 9027, siguiendo metodología estandarizada por la UNAM y fueron comparados con Pseudomonas aeruginosa PAO1. Nuestros resultados muestran que los genes estudiados en las cepas seleccionadas son sinónimas de sus homólogos en la cepa patrón Pseudomonas aeruginosa PAO1, por lo que las diferencias genotípicas que expliquen la sobreproducción de ramnolípidos deberían hallarse en otros marcadores moleculares no cubiertos en el presente estudio.
Genes associated to rhamnolipids production were molecularly characterized in 61 bacterial strains from LAMYBIM bacterial collection (Laboratorio de Microbiología y Biotecnología Microbiana, Universidad Nacional Mayor de San Marcos, Perú). Strains were isolated from peruvian environments hydrocarbons polluted and were classified as RL overproducers (n= 21), RL producers (n = 20) and non-producers (n = 20) producers. Molecular identification using the 16S rRNA gene was preceded by the biochemical identification of 61 strains selected with the API 20 NE system. Pseudomonas aeruginosa was the most prevalent strain of the RL overproducers and RL producers. Species such as Burkholderia cepacea, Pseudomonas fluorescens, Aeromonas hydrophila and Chryseobacterium indologenes, were found too. In the same way, non-producers microorganisms were also characterized. The PCR amplification and agarose gel electrophoresis techniques, standarized by the UNAM laboratory, showed that the selected strains had the genes: rhlA, rhlB, rhlR and rhlC. For the sequencing of the rhLABR gene region, four strains were selected: Pseudomonas aeruginosa T2K2, Pseudomonas aeruginosa III T1P2, Pseudomonas aeruginosa 6K-11 and Pseudomonas aeruginosa ATCC 9027, applying the methodology standardized by the UNAM and were compared with Pseudomonas aeruginosa PAO1. Our results show that the genes studied in the selected strains are synonymous with their homologues in Pseudomonas aeruginosa PAO1 standard strain. Therefore, genotypical differences that explain the overproduction of rhamnolipid might be found in other molecular markers not covered in this study.
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Although emerging nonviral pathogens remain relatively understudied in bat populations, there is an increasing focus on identifying bat-associated bartonellae around the world. Many novel Bartonella strains have been described from both bats and their arthropod ectoparasites, including Bartonella mayotimonensis, a zoonotic agent of human endocarditis. This cross-sectional study was designed to describe novel Bartonella strains isolated from bats sampled in Mexico and evaluate factors potentially associated with infection. A total of 238 bats belonging to seven genera were captured in five states of Central Mexico and the Yucatan Peninsula. Animals were screened by bacterial culture from whole blood and/or polymerase chain reaction of DNA extracted from heart tissue or blood. Bartonella spp. were isolated or detected in 54 (22.7%) bats, consisting of 41 (38%) hematophagous, 10 (16.4%) insectivorous, and three (4.3%) phytophagous individuals. This study also identified Balantiopteryx plicata as another possible bat reservoir of Bartonella. Univariate and multivariate logistic regression models suggested that Bartonella infection was positively associated with blood-feeding diet and ectoparasite burden. Phylogenetic analysis identified a number of genetic variants across hematophagous, phytophagous, and insectivorous bats that are unique from described bat-borne Bartonella species. However, these strains were closely related to those bartonellae previously identified in bat species from Latin America.
Assuntos
Infecções por Bartonella/genética , Infecções por Bartonella/microbiologia , Bartonella/genética , Bartonella/isolamento & purificação , Quirópteros/microbiologia , Animais , Estudos Transversais , Variação Genética , México , FilogeniaRESUMO
We implemented a spatial model for analysing PM 10 maxima across the Mexico City metropolitan area during the period 1995-2016. We assumed that these maxima follow a non-identical generalized extreme value (GEV) distribution and modeled the trend by introducing multivariate smoothing spline functions into the probability GEV distribution. A flexible, three-stage hierarchical Bayesian approach was developed to analyse the distribution of the PM 10 maxima in space and time. We evaluated the statistical model's performance by using a simulation study. The results showed strong evidence of a positive correlation between the PM 10 maxima and the longitude and latitude. The relationship between time and the PM 10 maxima was negative, indicating a decreasing trend over time. Finally, a high risk of PM 10 maxima presenting levels above 1000 µ g/m 3 (return period: 25 yr) was observed in the northwestern region of the study area.
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Poluentes Atmosféricos/análise , Monitoramento Ambiental/estatística & dados numéricos , Modelos Estatísticos , Material Particulado/análise , Poluição do Ar/análise , Teorema de Bayes , Cidades , México , Análise EspacialRESUMO
Bartonella species are highly endemic among wild rodents in many parts of the world. Blood and/or blood clot cultures from 38 rodents, including 27 Yucatan deer mouse (Peromyscus yucatanicus), 7 Gaumer's spiny pocket mouse (Heteromys gaumeri), 2 black rats (Rattus rattus) and 2 big-eared climbing rats (Ototylomys phyllotis) captured near Merida, Yucatan, Mexico, led to the isolation in 3-4 days of small gram-negative bacilli, which were identified as Bartonella spp. based on colony morphology. DNA extraction and PCR testing were also performed from heart samples of 35 of these 38 rodents. Overall, Bartonella spp. were isolated from the blood/blood clots of 22 (58%) rodents. All Bartonella-positive rodents were Yucatán deer mice from San José Pituch. Sequencing of a fragment of the gltA gene showed that all but one rodent isolates were closest to B. vinsonii subsp. vinsonii and one isolate was intermediate between B. vinsonii subsp. berkhoffii and B. vinsonii subsp. arupensis. Further analysis of concatenated housekeeping genes (gltA, ftsZ, rpoB, and 16S rRNA) suggests that this outlier isolate is a new subspecies within the B. vinsonii genogroup, for which we proposed the name B. vinsonii subsp. yucatanensis.
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Bartonella/classificação , Bartonella/isolamento & purificação , Roedores/microbiologia , Animais , Bartonella/genética , México , Filogenia , Reação em Cadeia da Polimerase , RNA Bacteriano/genética , RNA Ribossômico 16S/genéticaRESUMO
Bond failures are produced by the existence of biofilm on the tooth surface. Because biofilm is impermeable, it prevents contact in many areas, reducing the etching effect which selectively dissolves calcified tissues but does not seem to eliminate biofilm from the tooth surface, and thus the bond between the tooth and the bracket is not strong enough. The aim of this study is to compare bracket bonding efficiency with two dental surface pretreatments: sodium hypochlorite vs. hydrogen peroxide techniques. This was a cross-sectional, comparative, in vitro study. Seventy-five premolars extracted for orthodontic purposes were evaluated. They were divided into three groups of 25 teeth and assigned randomly toone of the pretreatment techniques (5.25%sodium hypochlorite or 3.5% hydrogen peroxide) or to a control group. The most efficient pretreatment technique for bonding to brackets was sodium hypochlorite, with an average of 17.15 (kg/F). Significant differences were observed between groups (p=0.0001). The post hoc bond strength test showed statistically significant differences between the sodium hypochlorite technique and the control group (p=0.0001). The sodium hypochlorite technique improves bracket adhesion to tooth enamel.
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Esmalte Dentário , Condicionamento Ácido do Dente , Estudos Transversais , Colagem Dentária , Análise do Estresse Dentário , Peróxido de Hidrogênio , Braquetes Ortodônticos , Cimentos de Resina , Resistência ao Cisalhamento , Hipoclorito de Sódio , Propriedades de SuperfícieRESUMO
Bond failures are produced by the existence of biofilm on the tooth surface. Because biofilm is impermeable, it prevents contact in many areas, reducing the etching effect which selectively dissolves calcified tissues but does not seem to eliminate biofilm from the tooth surface, and thus the bond between the tooth and the bracket is not strong enough. The aim of this study is to compare bracket bonding efficiency with two dental surface pretreatments: sodium hypochlorite vs. hydrogen peroxide techniques. This was a cross-sectional, comparative, in vitro study. Seventy-five premolars extracted for orthodontic purposes were evaluated. They were divided into three groups of 25 teeth and assigned randomly toone of the pretreatment techniques (5.25%sodium hypochlorite or 3.5% hydrogen peroxide) or to a control group. The most efficient pretreatment technique for bonding to brackets was sodium hypochlorite, with an average of 17.15 (kg/F). Significant differences were observed between groups (p=0.0001). The post hoc bond strength test showed statistically significant differences between the sodium hypochlorite technique and the control group (p=0.0001). The sodium hypochlorite technique improves bracket adhesion to tooth enamel.
Las fallas de adhesion se producen por la existencia de la biopelicula en la superficie del organo dental, ya que es impermeable y no permite el contacto en muchas areas, de manera que disminuye el efecto del grabado acido; el cual tiene la capacidad de disolver selectivamente los tejidos calcificados, pero no parece eliminar la biopelicula en la superficie dental, por lo tanto, no se lleva a cabo la suficiente fuerza de adhesion en la interfase diente-bracket. El objetivo es comparar la eficiencia en la adhesion de los brackets con el empleo de dos metodos de pre-tratamientos de la superficie del esmalte, el hipoclorito de sodio vs. peroxido de hidrogeno. Estudio comparativo, transversal, in vitro. Se evaluaron 75 premolares extraidos con fines ortodoncicos, tres grupos de 25 dientes, asignados aleatoriamente con alguna de las dos tecnicas de pre-tratamiento al esmalte, hipoclorito de sodio al 5.25%, peroxido de hidrogeno al 3.5% y un grupo control. La tecnica de pre-tratamiento al esmalte mas eficiente para la fuerza de adhesion a los brackets fue el hipoclorito de sodio, con una media de 17.15 (Kg/F), se observaron diferencias significativas inter-grupos (p= 0.001). Las pruebas post hoc para las fuerzas de adhesion mostraron diferencia estadistica - mente significativa para la tecnica de hipoclorito de sodio/ grupo control (p=.001). La utilizacion de hipoclorito de sodio ayuda a mejorar la adhesion de los brackets en la superficie del esmalte.
Assuntos
Esmalte Dentário , Hipoclorito de Sódio , Propriedades de Superfície , Condicionamento Ácido do Dente , Estudos Transversais , Colagem Dentária , Braquetes Ortodônticos , Cimentos de Resina , Resistência ao Cisalhamento , Análise do Estresse Dentário , Peróxido de HidrogênioRESUMO
BACKGROUND: Almost everyone on the planet has suffered dental caries. It is why dental caries are considered a public health problem. The anticariogenic efficacy of dental sealants for pits and fissures is related to their retention. Air abrasion and acid etching are two current techniques for applying pit and fissure sealants. Our objective was to compare the efficiency of retention a pit and fissure sealant in primary dental organs pre-conditioned with acid etching and air abrasion. METHODS: A descriptive, comparative study was conducted in 40 primary dental organs randomly divided into two groups for conditioning the enamel with one or the other technique. Sealants and double-standard mesh for brackets with double ligatures were applied to test shear bond strength with an Inströn testing machine. Student's t-test was used to compare the shear-peel bond strength exerted by the two techniques. RESULTS: The average traction tolerated in the group treated with air abrasion was 2.62 kgf, and in the group treated with acid etching was 3.55 kgf, with statistically significant differences (p=0.007). CONCLUSIONS: Acid etching demonstrated greater efficiency than air abrasion for retention of dental sealant for small pits and fissures in primary teeth.