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The MHYT domain, identified over two decades ago for its potential to detect diatomic gases like CO, O2 or NO, has awaited experimental validation as a protein sensory domain. Here, we characterize the MHYT domain-containing transcriptional regulator CoxC, which governs the expression of the cox genes responsible for aerobic CO oxidation in the carboxidotrophic bacterium Afipia carboxidovorans OM5. The C-terminal LytTR-type DNA-binding domain of CoxC binds to an operator region consisting of three direct repeats sequences overlapping the -35 box at the target PcoxB promoter, which is consistent with the role of CoxC as a specific transcriptional repressor of the cox genes. Notably, the N-terminal transmembrane MHYT domain endows CoxC with the ability to sense CO as an effector molecule, as demonstrated by the relief of CoxC-mediated repression and binding to the PcoxB promoter upon CO exposure. Furthermore, copper serves as the essential divalent cation for the interaction of CO with CoxC, thereby confirming previous hypothesis regarding the role of copper in the gas-sensing mechanism of MHYT domains. CoxC represents the prototype of a novel subfamily of single-component LytTR transcriptional regulators, characterized by the fusion of a DNA-binding domain with a membrane-bound MHYT sensor domain.
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Introduction: Biovigilance (BV) systems aim to improve the quality and safety of tissues and organs for transplantation. This study describes the Catalan BV system and analyzes its utility. Methods: It is a retrospective analysis of notifications on serious adverse events (SAEs) and reactions (SARs) since the implementation of the BV system (2008 for tissues and 2016 for organs) until 2020. Variables are presented to describe the most common critical steps of the pathway and complications associated with the quality and safety of tissues and organs. Results: A total of 154 and 125 notifications were reported to the Tissue and the Organ BV systems, respectively. Most SAEs were related to unexpected donor diseases and implemented actions were assured on those deemed preventable. Regarding SARs, donor-transmitted infections and malignancies (only organs) were the most common, followed by graft failure (tissues) and process-related (organs). The incidence of SAEs and SARs related to tissue was 3.44 and 0.22, respectively. The corresponding figures for organs were 31.48 and 8.8, respectively. Discussion: The analysis of the notifications to the Catalan BV systems has provided useful information about existing risks associated with the quality and safety of tissues and organs, and enabled the implementation of actions targeted to diminish risks and mitigate damage.
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"Tandem" uncaging systems, in which a photolabile protecting group (PPG) is sensitized by an energy-harvesting antenna, may increase the photosensitivity of PPGs by several orders of magnitude for two-photon (2P) photorelease. Yet, they remain poorly accessible because of arduous multi-step synthesis. In this work, we design efficient tandem uncaging systems by (i) using a convenient assembly of the building blocks relying on click chemistry, (ii) H-bonding induced proximity thus facilitating (iii) photoinduced electron transfer (PeT) as a cooperative mechanism. A strong two-photon absorber electron-donating quadrupolar antenna and various electron-accepting PPGs (mDEAC, MNI or MDNI) were clicked stepwise onto a "tweezer-shaped" pyrido-2,6-dicarboxylate platform whose H-bonding and p-stacking abilities were exploited to keep the antenna and the PPGs in close proximity. The different electron acceptor ability of the PPGs led to dyads with wildly different behaviors. Whilst the MDNI and MNI dyads showed poor dark stability or no photo-uncaging ability due to their too high electron accepting character, the mDEAC dyad benefited from optimum redox potentials to promote PeT and slow down charge recombination, resulting in enhanced uncaging quantum yield (Fu=0.38) compared to mDEAC (Fu=0.014). The unique resulted in large 2P photo-sensitivity in the near-infrared window (240 GM at 710 nm).
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Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared a pandemic by the World Health Organization in March 2020. Since then, viral spread from humans to animals has occurred worldwide. Nonhuman primates (NHPs) have been found to be susceptible to reverse-zoonosis transmission of SARS-CoV-2, but initial research suggested that platyrrhine primates are less susceptible than catarrhine primates. Here we report the natural SARS-CoV-2 infection of a common woolly monkey (Lagothrix lagothricha) from a wildlife rehabilitation center in Ecuador. The course of the disease, the eventual death of the specimen, and the pathological findings are described. Our results show the susceptibility of a new platyrrhine species to SARS-CoV-2 and provide evidence for the first time of a COVID-19-associated death in a naturally infected NHP. The putative route of transmission from humans, and implications for captive NHPs management, are also discussed. Given that common woolly monkeys are at risk of extinction in Ecuador, further understanding of the potential threat of SARS-CoV-2 to their health should be a conservation priority. A One Health approach is the best way to protect NHPs from a new virus in the same way that we would protect the human population.
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Atelinae , COVID-19 , Doenças dos Macacos , SARS-CoV-2 , Animais , COVID-19/veterinária , COVID-19/mortalidade , COVID-19/transmissão , Atelinae/virologia , Equador/epidemiologia , Doenças dos Macacos/virologia , Evolução Fatal , Masculino , FemininoRESUMO
Scientific conferences and meetings are valuable opportunities for researchers to network, communicate, and develop knowledge. For early career scientists, conferences can also be intimidating, confusing, and overwhelming, especially without having adequate preparation or experience. In this Perspective, we provide advice based on previous experiences navigating scientific meetings and conferences. These guidelines outline parts of the hidden curriculum around preparing for and attending meetings, navigating conference sessions, networking with other scientists, and participating in social activities while upholding a recommended code of conduct.
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Congressos como Assunto , Currículo , HumanosRESUMO
Schistosomiasis, caused by a parasitic blood fluke of the genus Schistosoma, is a global health problem for which new chemotherapeutic options are needed. We explored the scaffold of gallinamide A, a natural peptidic metabolite of marine cyanobacteria that has previously been shown to inhibit cathepsin L-type proteases. We screened a library of 19 synthetic gallinamide A analogs and identified nanomolar inhibitors of the cathepsin B-type protease SmCB1, which is a drug target for the treatment of schistosomiasis mansoni. Against cultured S. mansoni schistosomula and adult worms, many of the gallinamides generated a range of deleterious phenotypic responses. Imaging with a fluorescent-activity-based probe derived from gallinamide A demonstrated that SmCB1 is the primary target for gallinamides in the parasite. Furthermore, we solved the high-resolution crystal structures of SmCB1 in complex with gallinamide A and its two analogs and describe the acrylamide covalent warhead and binding mode in the active site. Quantum chemical calculations evaluated the contribution of individual positions in the peptidomimetic scaffold to the inhibition of the target and demonstrated the importance of the P1' and P2 positions. Our study introduces gallinamides as a powerful chemotype that can be exploited for the development of novel antischistosomal chemotherapeutics.
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Catepsina B , Schistosoma mansoni , Catepsina B/antagonistas & inibidores , Catepsina B/metabolismo , Animais , Schistosoma mansoni/enzimologia , Schistosoma mansoni/efeitos dos fármacos , Cristalografia por Raios X , Esquistossomicidas/farmacologia , Esquistossomicidas/química , Ligação Proteica , Modelos MolecularesRESUMO
Current small-molecule-based SARS-CoV-2 treatments have limited global accessibility and pose the risk of inducing viral resistance. Therefore, a marine algae and cyanobacteria extract library was screened for natural products that could inhibit two well-defined and validated COVID-19 drug targets, disruption of the spike protein/ACE-2 interaction and the main protease (Mpro) of SARS-CoV-2. Following initial screening of 86 extracts, we performed an untargeted metabolomic analysis of 16 cyanobacterial extracts. This approach led to the isolation of an unusual saturated fatty acid, jobosic acid (2,5-dimethyltetradecanoic acid, 1). We confirmed that 1 demonstrated selective inhibitory activity toward both viral targets while retaining some activity against the spike-RBD/ACE-2 interaction of the SARS-CoV-2 omicron variant. To initially explore its structure-activity relationship (SAR), the methyl and benzyl ester derivatives of 1 were semisynthetically accessed and demonstrated acute loss of bioactivity in both SARS-CoV-2 biochemical assays. Our efforts have provided copious amounts of a fatty acid natural product that warrants further investigation in terms of SAR, unambiguous determination of its absolute configuration, and understanding of its specific mechanisms of action and binding site toward new therapeutic avenues for SARS-CoV-2 drug development.
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Antivirais , Metabolômica , SARS-CoV-2 , SARS-CoV-2/efeitos dos fármacos , Antivirais/farmacologia , Antivirais/química , Antivirais/isolamento & purificação , Humanos , Cianobactérias/química , Relação Estrutura-Atividade , Ácidos Graxos/química , Ácidos Graxos/farmacologia , COVID-19 , Estrutura Molecular , Proteases 3C de Coronavírus/antagonistas & inibidores , Proteases 3C de Coronavírus/metabolismoRESUMO
BACKGROUND: Leptospirosis is the world's most common zoonotic disease. Mitigation and control rely on pathogen identification and understanding the roles of potential reservoirs in cycling and transmission. Underreporting and misdiagnosis obscure the magnitude of the problem and confound efforts to understand key epidemiological components. Difficulties in culturing hamper the use of serological diagnostics and delay the development of DNA detection methods. As a result, especially in complex ecosystems, we know very little about the importance of different mammalian host species in cycling and transmission to humans. METHODOLOGY/PRINCIPAL FINDINGS: We sampled dogs from five indigenous Kichwa communities living in the Yasuní National Park in the Ecuadorian Amazon basin. Blood and urine samples from domestic dogs were collected to assess the exposure of these animals to Leptospira and to identify the circulating species. Microscopic Agglutination Tests with a panel of 22 different serovars showed anti-leptospira antibodies in 36 sampled dogs (75%), and 7 serogroups were detected. Two DNA-based detection assays revealed pathogenic Leptospira DNA in 18 of 19 dog urine samples (94.7%). Amplicon sequencing and phylogenetic analysis of 16S rRNA and SecY genes from 15 urine samples revealed genetic diversity within two of three different Leptospira species: noguchii (n = 7), santarosai (n = 7), and interrogans (n = 1). CONCLUSIONS/SIGNIFICANCE: The high prevalence of antibodies and Leptospira DNA provides strong evidence for high rates of past and current infections. Such high prevalence has not been previously reported for dogs. These dogs live in the peridomestic environment in close contact with humans, yet they are free-ranging animals that interact with wildlife. This complex web of interactions may explain the diverse types of pathogenic Leptospira observed in this study. Our results suggest that domestic dogs are likely to play an important role in the cycling and transmission of Leptospira. Future studies in areas with complex ecoepidemiology will enable better parsing of the significance of genotypic, environmental, and host characteristics.
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Leptospira , Leptospirose , Animais , Cães , Humanos , Ecossistema , Filogenia , RNA Ribossômico 16S/genética , Leptospirose/epidemiologia , Leptospirose/veterinária , Animais Selvagens , DNA , MamíferosRESUMO
BACKGROUND: Human records describe pulmonary edema as a life-threatening complication of electric shock. Successful management requires prompt recognition and intensive care. However, in companion animals, electrocutions are rarely reported, even though domestic environments are full of electrical devices and there is always the possibility of accidental injury. Therefore, it is important for veterinarians to know more about this condition in order to achieve successful patient outcomes. CASE PRESENTATION: A 3-month-old male Labrador Retriever was presented with a history of transient loss of consciousness after chewing on a household electrical cord. On admission, the puppy showed an orthopneic position with moderate respiratory distress. Supplemental oxygen via nasal catheter was provided, but the patient showed marked worsening of respiratory status. Point-of-care ultrasound exams suggested neurogenic pulmonary edema due to electrical shock close to the central nervous system and increased B-lines without evidence of cardiac abnormalities. Mechanical ventilation of the patient was initiated using volume-controlled mode with a tidal volume of 9 to 15 ml/kg until reaching an end-tidal carbon dioxide ≤ 40 mm Hg, followed by a stepwise lung-recruitment maneuver in pressure-controlled mode with increases of the peak inspiratory pressure (15 to 20 cm H2O) and positive end-expiratory pressure (3 to 10 cm H2O) for 30 min, and return to volume-controlled mode with a tidal volume of 15 ml/kg until reaching a peripheral oxygen saturation ≥ 96%. Weaning from the ventilator was achieved in six hours, and the patient was discharged two days after admission without neurological or respiratory deficits. CONCLUSIONS: We present a rather unusual case of a neurogenic pulmonary edema subsequent to accidental electrocution in a dog. Timely diagnosis by ultrasound and mechanical ventilation settings are described. Our case highlights that pulmonary edema should be considered a potentially life-threatening complication of electrical shock in small animal emergency and critical care medicine.
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Doenças do Cão , Traumatismos por Eletricidade , Edema Pulmonar , Síndrome do Desconforto Respiratório , Animais , Cães , Masculino , Doenças do Cão/etiologia , Doenças do Cão/terapia , Traumatismos por Eletricidade/complicações , Traumatismos por Eletricidade/terapia , Traumatismos por Eletricidade/veterinária , Pulmão , Edema Pulmonar/etiologia , Edema Pulmonar/terapia , Edema Pulmonar/veterinária , Respiração Artificial/veterinária , Síndrome do Desconforto Respiratório/veterináriaRESUMO
Livestock predation induces global human-wildlife conflict, triggering the retaliatory killing of large carnivores. Although domestic dogs (Canis familiaris) contribute to livestock depredation, blame primarily falls on wild predators. Dogs can also transmit pathogens between wildlife, domestic animals, and humans. Therefore, the presence of free-ranging dogs can have negative consequences for biodiversity conservation, smallholder economy, food supply, and public health, four of the United Nations' Sustainable Developed Goals (SDGs) for 2030. In Ecuador, where livestock sustains rural households, retaliatory poaching threatens Andean bear (Tremarctos ornatus), jaguar (Panthera onca), and puma (Puma concolor) populations. However, the role of dogs in these incidents remains underexplored. The present study evaluates the possibility of reliable molecular identification of predatory species from DNA traces in bite wounds. Our results revealed the presence of dog saliva on four out of six livestock carcasses presumably attacked by wild predators. These findings highlight the importance of rectifying misinformation about large carnivores in Ecuador and the need to control dog populations. We recommend that local administrations incorporate DNA analysis into livestock predation events to examine how common the problem is, and to use the analysis to develop conflict mitigation strategies which are essential for the conservation of large carnivores.
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Dissecting the role of the thalamus in neuropsychiatric disorders requires new models to analyze complex genetic interactions. In this issue of Cell Stem Cell, Shin et al. use patient-derived thalamocortical organoids to investigate 22q11.2 microdeletion impact on thalamic development, revealing significant transcriptional dysregulation linked to psychiatric disorders.
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Córtex Cerebral , Transtornos Mentais , Humanos , Vias Neurais , Transtornos Mentais/genética , Tálamo , OrganoidesRESUMO
Human populations can be affected in unpredictable ways by the emergence and spread of zoonotic diseases. The COVID-19 (coronavirus disease of 2019) pandemic was a reminder of how devastating these events can be if left unchecked. However, once they have spread globally, the impact of these diseases when entering non-exposed wildlife populations is unknown. The current study reports the infection of brown-headed spider monkeys (Ateles fusciceps) at a wildlife rescue center in Ecuador. Four monkeys were hospitalized, and all tested positive for SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) by RT-qPCR (Quantitative Reverse Transcription PCR). Fecal samples (n = 12) from monkeys at the rescue center also tested positive; three zookeepers responsible for feeding and deworming the monkeys also tested positive, suggesting human-animal transmission. Whole genome sequencing identified most samples' omicron clade 22B BA.5 lineage. These findings highlight the threat posed by an emerging zoonotic disease in wildlife species and the importance of preventing spillover and spillback events during epidemic or pandemic events.IMPORTANCEAlthough COVID-19 (coronavirus disease of 2019) has been primarily contained in humans through widespread vaccination, the impact and incidence of SARS-CoV-2 (Severe acute respiratory syndrome coronavirus) and its transmission and epidemiology in wildlife may need to be addressed. In some natural environments, the proximity of animals to humans is difficult to control, creating perfect scenarios where susceptible wildlife can acquire the virus from humans. In these places, it is essential to understand how transmission can occur and to develop protocols to prevent infection. This study reports the infection of brown-headed spider monkeys with SARS-CoV-2, a red-listed monkey species, at a wildlife recovery center in Ecuador. This study reports the infection of brown-headed spider monkeys with SARS-CoV-2, indicating the potential for transmission between humans and wildlife primates and the importance of preventing such events in the future.
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Atelinae , COVID-19 , Animais , Humanos , Animais Selvagens , COVID-19/epidemiologia , COVID-19/veterinária , Equador/epidemiologia , SARS-CoV-2/genética , Zoonoses/epidemiologia , América do Sul , PandemiasRESUMO
This paper stems from the hypothesis that there are various key factors rooted in economic, political, and social grounds which actively influence and determine the adoption and evolution of LGBT+ rights in the legal framework of any country. The goal of this research is to analyze these factors and understand how they channel the LGBT+ legislation in our present world. Assuming there is an asymmetry in this application and by extension in LGBT+ individuals' human rights, which are often ignored if not deprived in many parts of the world, this study seeks to understand the reasons behind that asymmetry. Based on a sample of 127 countries, a correlation analysis and a Panel data model were developed to analyze the real impact of these factors.
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Bissexualidade , Minorias Sexuais e de Gênero , Humanos , Direitos Humanos , Motivação , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Despite evidence demonstrating that lung cancer screening (LCS) decreases mortality, widespread implementation is lagging. Efforts to identify and recruit patients for LCS are in need. Candidacy for LCS is based on identifiable risk factors, many of which overlap with those of head and neck malignancies. Thus, we aimed to evaluate the prevalence of candidacy for LCS in the head and neck cancer patient population. METHODS: We performed a review of anonymous surveys collected from patients who presented to a head and neck cancer clinic. Variables collected from these surveys included age, biologic sex, smoking history, and head and neck cancer history. Patients' candidacy for screening was determined, and descriptive analyses were performed. RESULTS: A total of 321 patient surveys were reviewed. Mean age was 63.7 years, and 195 (60.7%) were men. In this sample, 19 (5.91%) were current smokers, and 112 (34.9%) were former smokers, having quit an average of 19.4 years prior to completing the survey. Average pack-years was 29.3. Of the 321 patients surveyed, 60 (18.7%) would qualify for LCS using current guidelines. However, among those 60 patients who qualified for LCS, only 15 (25%) patients had been offered screening and only 14 (23.3%) had been screened. CONCLUSIONS: We have importantly demonstrated both a substantial prevalence of candidacy for LCS in the head and neck cancer population as well as disappointingly low levels of screening utilization in this group of patients. We have identified this setting as a key patient population that ought to be targeted for information about and access to LCS.
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Neoplasias de Cabeça e Pescoço , Neoplasias Pulmonares , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Detecção Precoce de Câncer , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/epidemiologia , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/prevenção & controle , Programas de Rastreamento , Fatores de Risco , Fumar/efeitos adversos , Fumar/epidemiologiaRESUMO
BACKGROUND: The watch-and-wait (WW) strategy is a potential option for patients with rectal cancer who obtain a complete clinic response after neoadjuvant therapy. The aim of this study is to analyze the long-term oncological outcomes and perform a cost-effectiveness analysis in patients undergoing this strategy for rectal cancer. MATERIAL AND METHODS: The data of patients treated with the WW strategy were prospectively collected from January 2015 to January 2020. A control group was created, matched 1:1 from a pool of 480 patients undergoing total mesorectal excision. An independent company carried out the financial analysis. Clinical and oncological outcomes were analyzed in both groups. Outcome parameters included surgical and follow-up costs, quality-adjusted life years (QALYs), and the incremental cost per QALY gained or the incremental cost-effectiveness ratio (ICER). RESULTS: Forty patients were included in the WW group, with 40 patients in the surgical group. During a median follow-up period of 36 months, metastasis-free survival (MFS) and overall survival (OS) were similar in the two groups. In the WW group, nine (22%) local regrowths were detected in the first 2 years. The permanent stoma rate was slightly higher after salvage surgery in the WW group compared to the surgical group (48.5% vs 20%, p < 0.01). The cost-effectiveness analysis was slightly better for the WW group, especially for low rectal cancer compared to medium-high rectal cancer (ICER = - 108,642.1 vs ICER = - 42,423). CONCLUSIONS: The WW strategy in locally advanced rectal cancer offers similar oncological outcomes with respect to the surgical group and excellent results in quality of life and cost outcomes, especially for low rectal cancer. Nonetheless, the complex surgical field during salvage surgery can lead to a high permanent stoma rate; therefore, the careful selection of patients is mandatory.
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Análise de Custo-Efetividade , Neoplasias Retais , Humanos , Qualidade de Vida , Neoplasias Retais/cirurgia , Reto , Indução de Remissão , Terapia Neoadjuvante , Conduta Expectante/métodos , Recidiva Local de Neoplasia , Resultado do Tratamento , QuimiorradioterapiaRESUMO
BACKGROUND: The emblematic Galapagos sea lion (GSL-Zalophus wollebaeki) has faced an important population decline over the last four decades. There are multiple environmental and biological factors that might be implied in this decrease. Recently, evidence of various zoonotic infectious diseases that can be potential threats has been reported. Considering that in some islands of the archipelago the risk of transmission of infectious diseases may be promoted by the increasing population of domestic dogs, epidemiological vigilance and search of new pathogens are essential. The canine distemper virus (CDV), one of the viral pathogens that generate the most concern for the agencies responsible for the management and conservation of the Galapagos pinnipeds, was detected in the GSL in 2010. However, there is scarce information about its impact on GSL health and about its epidemiology. METHODS: In this study, 110 GSL serum samples were collected during the summer of 2016 and 2017. All samples were exposed to VERO dog SLAM cells expressing the canine SLAM receptor. RESULTS: Our results showed a significative increase (p = 0.04) in the frequency of neutralizing antibodies to CDV in the 2017 (53.1%) samples compared to the 2016 samples (19.6%). CONCLUSIONS: Our work confirmed the continuous and increasing circulation of the CDV in the GSL and highlights the importance of monitoring emerging diseases that can be transmitted from domestic to wildlife species. Vigilance of CDV is essential to understand the role of this virus in GSL mortality and to take informed decisions for wildlife conservation.
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INTRODUCTION: Acute cardiac tamponade is a rare event during any type of interventional or surgical procedure. It can occur during electrophysiology procedures due to radiofrequency ablation, lead or catheter manipulation, transseptal puncture, laser lead extractions, or left atrial appendage occlusion device positioning. Cardiac tamponade is difficult to study in a prospective manner, and case reports and case series are important contributions to understanding the best options for patient care. An 87-year-old Caucasian male patient breathing spontaneously developed acute tamponade during an atrial flutter ablation. Pericardial drain insertion was difficult, and hypotension failed to respond to epinephrine boluses. The patient became hypoxemic and hypercarbic, requiring intubation. Unexpectedly, the blood pressure markedly increased postintubation and remained in a normal range until the pericardium was drained. CONCLUSION: Spontaneous ventilation is considered important to maintain venous return to the right heart during cardiac tamponade. However, spontaneous ventilation reduces venous return to the left heart and worsens the paradoxical pulse in tamponade. Intravenous vasopressors are thought to be ineffective during cardiac tamponade. Our patient maintained pulmonary blood flow as indicated by end-tidal carbon dioxide measurements but had no measurable systemic blood pressure during spontaneous ventilation. Our case demonstrates that tracheal intubation and positive pressure ventilation can transiently improve left heart venous return, systemic perfusion, and drug delivery to the systemic circulation.
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Flutter Atrial , Tamponamento Cardíaco , Ablação por Cateter , Idoso de 80 Anos ou mais , Humanos , Masculino , Flutter Atrial/cirurgia , Flutter Atrial/complicações , Tamponamento Cardíaco/etiologia , Tamponamento Cardíaco/cirurgia , Ablação por Cateter/efeitos adversos , Ablação por Cateter/métodos , Hemodinâmica/fisiologia , Respiração com Pressão Positiva , Estudos ProspectivosRESUMO
Background and Aim: Leptospirosis is considered a neglected tropical zoonosis in low-income countries due to surveillance system limitations and non-specificity of symptoms. Humans become infected through direct contact with carrier animals or indirectly through Leptospira-contaminated environments. Conventionally, equines have been considered an uncommon source of leptospirosis, but recent publications in Latin America suggest that their role in the maintenance and dispersion of the bacteria could be more relevant than expected, as horses are susceptible to a wide variety of zoonotic Leptospira spp. from domestic and wild animals with which they share the environment. A systematic review of the published literature was conducted to compile the available information on Leptospira spp. in Ecuador, with a special focus on equine leptospirosis, to better understand the epidemiology of the bacterium and identify possible knowledge gaps. Materials and Methods: A systematic review of the published literature was conducted in PubMed, SciELO and Web of Science databases to compile the available information on Leptospira spp. in Ecuador, with a special focus on equine leptospirosis, to better understand the epidemiology of the bacterium. We used a combination of the terms (Leptospira OR Leptospirosis) AND Ecuador, without restrictions on language or publication date. Results: Our literature review reveals that published scientific information is very scarce. Eighteen full-text original scientific articles related to Leptospira or leptospirosis cases in Ecuador were included in the systematic review. Most of the studies reported data obtained from one of the four regions (Coast), and specifically from only one of the 24 Provinces of Ecuador (Manabí), which evidence a large information bias at the geographical level. Furthermore, only the studies focused on humans included clinical signs of leptospirosis and there is only one study that analyzes the presence of Leptospira spp. in water or soil as a risk factor for pathogen transmission. Finally, only one study investigated Leptospira in horses. Conclusion: Since sentinel species can provide useful data on infectious diseases when epidemiologic al information is lacking, and horses could be considered excellent sentinel species to reveal circulating serovars, we propose developing a nationwide surveillance system using horses. This cost-effective epidemiological survey method provides a baseline for implementing specific prevention and control programs in Ecuador and neighboring developing countries.
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Nanostructured porous silicon (pSi) is a synthetic silicon-based material. Its biocompatibility and bioresorbability in body fluids make pSi an appealing biomaterial for tissue engineering, with surfaces characteristics facilitating human cell adhesion and differentiation. The resorption kinetics of such porous biomaterials is crucial for in vivo bone regeneration, in order to adapt biomaterial resorption to tissue formation, and to control the release of loaded bioactive molecules. We investigated pSi as a bioactive scaffold for bone tissue engineering, with an emphasis on kinetics of pSi resorption and silicon release. PSi particles and chips were fabricated from crystalline silicon, and functionalized by oxidation and chemical grafting of amine groups to mimic biological structures. Materials resorption over time was investigated with Raman spectroscopy, infrared spectroscopy, and Scanning Electron Microscopy. Silicon release was followed by mass spectrometry. Particle degradation and inclusion in newly formed bone were studied in vivo. The in vitro experiments revealed that non-oxidized pSi had an accelerated initial dissolution in ddH2O and an inhibition of initial Si release in SBF. This high reactivity also led to transformation towards amorphous non-resorbable silica when incubated in SBF. PSi resorption started immediately with a maximal dissolution in the first 24 h. Later, the dissolution rate decreased over time. In comparison, the resorption process of oxidized pSi seemed delayed, but more continuous. This delayed dissolution increased the bioactivity and stability, leading to enhanced bone formation in vivo. Delayed pSi degradation provided a constant surge of silicic acid over time and promoted bone regeneration, demonstrating the high potential of pSi for bone tissue engineering: Oxidized pSi were almost completely resorbed after 2 months of healing, with remaining partially dissolved particles surrounded by newly formed bone. On the contrary, non-oxidized particles were still obviously present after 2 months with limited bone regeneration. This delayed resorption is consistent with the in vitro observations in SBF, and particles' transformation towards silica.