Antiparasitic activity of chalcones analogue against Trichomonas vaginalis: biochemical, molecular and in silico aspects.

Trichomonas vaginalis is the etiologic agent of trichomoniasis, a worldwide distributed sexually transmitted infection (STI) that affects the genitourinary tract. Even though this disease already has a treatment in the prescription of drugs of the 5-nitroimidazole class, described low treatments adhesion, adverse side effects and cases of resistant isolates demonstrate the need for new formulations. With this in mind, chalcones emerge as a potential alternative to be tested, being compounds widely distributed in nature, easy to chemically synthesize and presenting several biological activities already reported. In this experiment, we evaluated the antiparasitic activity of 10 chalcone at a concentration of 100 µM against ATCC 30236 T. vaginalis isolates, considering negative (live trophozoites), positive (Metronidazole 100 µM) and vehicle (DMSO 0.6%) controls. Compounds 3a, 3c, 3 g and 3i showed promising results, with MICs set at 70 µM, 80 µM, 90 µM and 90 µM, respectively (p < 0,05). Cytotoxicity assays were performed on VERO and HMVII cell lines and revealed low inhibition rates at concentrations bellow 20 µM. To elucidate a possible mechanism of action for these molecules, the DPPH, ABTS and FRAP assays were performed, in which none of the four compounds presented antioxidant activity. Assays to verify ROS and lipid peroxidation in the parasite membrane were performed. None of the tested compounds identified ROS accumulation after incubation with trophozoites. 3 g molecule promoted an increase in MDA production after incubation. Results presented in this paper demonstrate the promising trichomonicidal profile, although further tests are still needed to optimize their performance and better elucidate the mechanisms of action involved.

Concepts on Accumulation of Pesticides and Veterinary Drugs in Fish: A Review with Emphasis in Tilapia.

The quality of the aquatic environment can be compromised by the practice of intensive use of pesticides in agriculture and by the misuse of veterinary drugs. Therefore, organisms that live in aquatic ecosystems may be affected due to the presence of these chemicals, through runoff, leaching and other processes. Exposure of aquatic organisms to these xenobiotics could pose health risks. Consequently, there is a growing interest in predicting the bioaccumulation of these substances in aquatic biota from experiments conducted under laboratory conditions. Studies on fish have been performed due to its importance as human food and their wide distribution in most of the aquatic environment. Thus, this article reviews the concepts on determining the accumulation of pesticides and veterinary drugs in fish. The risk regarding the consumption of fish containing residues of these chemical agents, the acceptable daily intake, the testing protocols and the analytical techniques used to determine the residues of these substances in fish tissues are discussed. An emphasis on studies involving tilapia as the test organism was included because, according to Food and Agricultural Organization (FAO), this species is one of the most cultivated in the world.

Antibacterial and antibiofilm activity of 1-thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H pyrazoles and thiazoles in multidrug-resistant pathogens.

To find novel antibiotic drugs, six 1-thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H derivatives named 1b, 1d (pyrazoles), 2a, 2b, 2c, and 2d (thiazoles) were evaluated in silico and in vitro. The in silico analyses were based on ADME pharmacokinetic parameters (absorption, distribution, metabolism, and excretion). The in vitro antibacterial activity was evaluated in Gram-positive and Gram-negative species (Staphylococcus aureus ATCC® 25904, Staphylococcus epidermidis ATCC® 35984, Klebsiella pneumoniae ATCC® 700603, and Acinetobacter baumannii ATCC® 19606), by determination of minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), kinetics curve, and antibiofilm assays. As results, the azoles have activity against the Gram-negative species K. pneumoniae ATCC® 700603 and A. baumannii ATCC® 19606. No antibacterial activity was observed for the Gram-positive bacteria evaluated. Thus, the azoles were evaluated against clinical isolates of K. pneumoniae carbapenemase (KPC) and A. baumannii multidrug-resistant (Ab-MDR). All azoles have antibacterial activity against Ab-MDR isolates (Gram-negative) with MIC values between 512 µg/mL and 1,024 µg/mL. Against KPC isolates the azoles 1b, 1d, and 2d present antibacterial activity (MIC = 1,024 µg/mL). In the kinetics curve assay, the 1b and 1d pyrazoles reduced significantly viable cells of Ab-MDR isolates and additionally inhibited 86.6 to 95.8% of the biofilm formation. The in silico results indicate high possibility to permeate the blood-brain barrier (2b) and was predict human gastrointestinal absorption (all evaluated azoles). Considering that the research and development of new antibiotics is a priority for drug-resistant pathogens, our study revealed the antibacterial and antibiofilm activity of novel azoles against K. pneumoniae and A. baumannii pathogens.

Comprehensive adsorption and spectroscopic studies on the interaction of magnetic biochar from black wattle sawdust with beta-blocker metoprolol.

The rise of contaminants of emerging concern in water-resources due to human activities has driven research toward wastewater treatment, specifically adsorption. The utilization of woody biomass for biochar production in adsorption has shown promise due to its high availability. This study shows the preparation of magnetic biochars (MB) from waste black wattle sawdust, utilizing ZnCl2 and NiCl2 (proportions: 1:0.5:0.5 = MB-0.5 and 1:1:1 = MB-1) as activating and magnetic agents. Synthesized via microwave-assisted-pyrolysis, MB boasts a high surface area (up to 765 m2.g-1) and functional groups, enhancing metoprolol medicine adsorption. Nonlinear kinetic and isothermal models were tested; the Avrami fractional-order kinetic model and Liu's isothermal model provided the best fits for experimental data. Thermodynamics and spectroscopic studies revealed spontaneous and exothermic adsorption processes, with physisorption magnitude and dominance of hydrogen-bond and π-π-interactions. MB can be easily extracted from an aqueous medium using magnetic fields, while adsorption capacity could be regenerated through green solvent elution.

Ecotoxicity studies of two atrazine nanoformulations: From the evaluation of stability in media to the effects on aquatic organisms.

In the field of agriculture, nanopesticides have been developed as an alternative to the conventional pesticides, being more efficient for pest control. However, before their widespread application it is essential to evaluate their safe application and no environmental impacts. In this paper, we evaluated the toxicological effects of two kinds of atrazine nanoformulations (ATZ NPs) in different biological models (Raphidocelis subcapitata, Danio rerio, Lemna minor, Artemia salina, Lactuca sativa and Daphnia magna) and compared the results with nanoparticle stability over time and the presence of natural organic matter (NOM). The systems showed different characteristics for Zein (ATZ NPZ) (184 ± 2 nm with a PDI of 0.28 ± 0.04 and zeta potential of (30.4 ± 0.05 mV) and poly(epsilon-caprolactone (ATZ PCL) (192 ± 3 nm, polydispersity (PDI) of 0.28 ± 0.28 and zeta potential of -18.8 ± 1.2 mV) nanoparticles. The results showed that there is a correlation between nanoparticles stability and the presence of NOM in the medium and Environmental Concentrations (EC) values. The stability loss or an increase in nanoparticle size result in low toxicity for R. subcapitata and L. minor. For D. magna and D. rerio, the presence of NOM in the medium reduces the ecotoxic effects for ATZ NPZ nanoparticles, but not for ATZ NPs, showing that the nanoparticles characteristics and their interaction with NOM can modulate toxic effects. Nanoparticle stability throughout the evaluation must be considered and become an integral part of toxicity protocol guidelines for nanopesticides, to ensure test quality and authentic results regarding nanopesticide effects in target and non-target organisms.

Bioprospection of the trichomonacidal activity of lipid extracts derived from marine macroalgae Gigartina skottsbergii.

Algal extracts are sources of bioactive substances with applications in the development of novel alternative drugs against several diseases, including trichomoniasis sexually transmitted infection caused by Trichomonas vaginalis. Factors such as clinical failures and resistant strains limit the success of the existing drugs available for treating this disease. Therefore, searching for viable alternatives to these drugs is essential for the treatment of this disease. The present study was conducted for, in vitro and in silico characterization of extracts obtained from marine macroalgae Gigartina skottsbergii at stages gametophidic, cystocarpic, and tetrasporophidic. In addition, antiparasitic activity of these extracts against the ATCC 30236 isolate of T. vaginalis, their cytotoxicity, and gene expression of trophozoites after treatment were evaluated. The minimum inhibitory concentration and 50% inhibition concentration were determined for each extract. Results: In vitro analysis of the extracts' anti-T. vaginalis activity revealed an inhibitory effect of 100%, 89.61%, and 86.95% for Gigartina skottsbergii at stages gametophidic, cystocarpic, and tetrasporophidic, respectively, at 100 µg/mL. In silico analysis revealed the interactions between constituents of the extracts and enzymes from T. vaginalis, with significant free energy values obtained for the binding. None of the extract concentrations exhibited cytotoxic effects on VERO cell line compared to control, while cytotoxicity on HMVII vaginal epithelial cells line was observed at 100 µg/mL (30% inhibition). Gene expression analysis revealed differences in the expression profile of T. vaginalis enzymes between the extract-treated and control groups. According to these results, Gigartina skottsbergii extracts exhibited satisfactory antiparasitic activity.

Carrageenan from Gigartina skottsbergii: A Novel Molecular Probe to Detect SARS-CoV-2.

The COVID-19 pandemic has caused an unprecedented health and economic crisis, highlighting the importance of developing new molecular tools to monitor and detect SARS-CoV-2. Hence, this study proposed to employ the carrageenan extracted from Gigartina skottsbergii algae as a probe for SARS-CoV-2 virus binding capacity and potential use in molecular methods. G. skottsbergii specimens were collected in the Chilean subantarctic ecoregion, and the carrageenan was extracted -using a modified version of Webber's method-, characterized, and quantified. After 24 h of incubation with an inactivated viral suspension, the carrageenan's capacity to bind SARS-CoV-2 was tested. The probe-bound viral RNA was quantified using the reverse transcription and reverse transcription loop-mediated isothermal amplification (RT-LAMP) methods. Our findings showed that carrageenan extraction from seaweed has a similar spectrum to commercial carrageenan, achieving an excellent proportion of binding to SARS-CoV-2, with a yield of 8.3%. Viral RNA was also detected in the RT-LAMP assay. This study shows, for the first time, the binding capacity of carrageenan extracted from G. skottsbergii, which proved to be a low-cost and highly efficient method of binding to SARS-CoV-2 viral particles.

Reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay as a rapid molecular diagnostic tool for COVID-19 in healthcare workers.

In December 2019, the Chinese Center for Disease Control (CDC of China) reported an outbreak of pneumonia in the city of Wuhan (Hubei province, China) that haunted the world, resulting in a global pandemic. This outbreak was caused by a betacoronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several of these cases have been observed in healthcare professionals working in hospitals and providing care on the pandemic's frontline. In the present study, nasopharyngeal swab samples of healthcare workers were used to assess the performance of the reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay and subsequently compared with the real-time reverse-transcription quantitative PCR (RT-qPCR) method. Thus, in this study, we validated a method for detecting SARS-CoV-2 based on RT-LAMP that can be used to diagnose these workers. The methodology used was based on analyzing the sensitivity, specificity, evaluation of the detection limit, and cross-reaction with other respiratory viruses. The agreement was estimated using a dispersion diagram designed using the Bland-Altman method. A total of 100 clinical specimens of nasopharyngeal swabs were collected from symptomatic and asymptomatic healthcare workers in Pelotas, Brazil, during the SARS-CoV-2 outbreak. RT-LAMP assay, it was possible to detect SARS-CoV-2 in 96.7% of the healthcare professionals tested using the E gene and N gene primers approximately and 100% for the gene of human ß-actin. The observed agreement was considered excellent for the primer set of the E and N genes (k = 0.957 and k = 0.896), respectively. The sensitivity of the RT-LAMP assay was positive for the primer set of the E gene, detected to approximately 2 copies per reaction. For the primer set of the N gene, the assay was possible to verify an LoD of approximately 253 copies per reaction. After executing the RT-LAMP assay, no positive reactions were observed for any of the virus respiratory tested. Therefore, we conclude that RT-LAMP is effective for rapid molecular diagnosis during the COVID-19 outbreak period in healthcare professionals.

Osteonecrosis múltiple inducida por glucocorticoides / Multiple osteonecrosis induced bye glucocorticoids / Osteonecrose múltipla induzida por glicocorticóides

La osteonecrosis múltiple es una entidad poco frecuente que se define por el compromiso de al menos tres regiones diferentes. Es indispensable el abordaje multidisciplinario de los pacientes que la padecen tanto para el diagnóstico como el tratamiento oportuno. Presentamos el caso clínico de un paciente joven que presenta una osteonecrosis múltiple con compromiso de ambas caderas, hombros, rodillas, codo derecho y cuello de pie izquierdo. El principal factor de riesgo presente en nuestro caso es el consumo de glucocorticoides.

Multiple osteonecrosis is a rare entity that is defined by the involvement of at least three different regions. A multidisciplinary approach to patients who suffer from it is essential for both diagnosis and timely treatment. We present the clinical case of a young patient who presented multiple osteonecrosis with involvement of both hips, shoulders, knees, right elbow, and neck of the left foot. The main risk factor present in our case is the consumption of glucocorticoids.

A osteonecrose múltipla é uma entidade rara que se define pelo envolvimento de pelo menos três regiões diferentes. Uma abordagem multidisciplinar aos pacientes que sofrem com isso é essencial para o diagnóstico e tratamento oportuno. Apresentamos o caso clínico de um paciente jovem que apresenta osteonecrose múltipla envolvendo quadris, ombros, joelhos, cotovelo direito e pescoço do pé esquerdo. O principal fator de risco presente no nosso caso é o consumo de glicocorticóides.

Synthesis of N-phenyl- and N-thiazolyl-1H-indazoles by copper-catalyzed intramolecular N-arylation of ortho-chlorinated arylhydrazones.

The broad application of 1H-indazoles has prompted the development of several approaches for the synthesis of such compounds, including metal-free, palladium-, or copper-promoted intramolecular N-arylation of in situ-generated or isolated o-haloarylhydrazones. Such methods mainly start from o-bromo derivatives due to the better yield observed when compared to those obtained from o-chloroarylhydrazones. However, the o-chloroarylaldehydes and o-chloroarylketones used to prepare the arylhydrazones are more commercially available and less expensive than brominated analogs. Seeking to cover a lack in the literature, this work reports a convenient protocol for the synthesis of N-phenyl- and N-thiazolyl-1H-indazoles by copper-catalyzed intramolecular N-arylation of o-chlorinated arylhydrazones. Therefore, a series of seven N-phenyl derivatives and a series of six novel N-thiazolyl derivatives was obtained in 10-70% and 12-35% yield, respectively, after stirring the o-chlorinated arylhydrazones, CuI, KOH, and 1,10-phenantroline for 12-48 hours in DMF at 120 °C. The products were isolated by column chromatography on silica gel. All products were fully characterized by HRMS as well as 1H and 13C NMR spectroscopy. Thus, this approach is valuable for promoting the synthesis of N-phenyl-1H-indazoles in a higher yield than that reported in the literature using copper catalysis and the same substrates. This study also prompted the first reported synthesis of pharmacologically interesting N-thiazolyl derivatives.

Dihydropyrimidinones Against Multiresistant Bacteria.

The increase in bacterial resistance to antimicrobials has led to high morbidity and mortality rates, posing a major public health problem, requiring the discovery of novel antimicrobial substances. The biological samples were identified as the Gram-negative bacilli Acinetobacter baumannii, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Morganella morgannii, Pseudomonas aeruginosa and Serratia marcescens and the Gram-positive cocci Enterococcus faecium, and Staphylococcus aureus, all of them resistant to at least three classes of antimicrobials. The antibacterial activity of the compounds was checked in vitro by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) by the broth microdilution method and plating in brain heart infusion (BHI) agar, respectively. The chemical characterization of the compounds was performed by measuring the melting point and gas chromatography coupled with mass spectrometry (GC-MS) on a Shimadzu GC-MS-QP system 2010SE. Synthetic compounds showed antimicrobial activity against Gram-positive cocci at MIC concentrations 0.16-80 µg/ml and Gram-negative bacilli at MIC concentrations 23.2-80 µg/ml. Enterococcus faecium and S. aureus had the best MIC values. The results of the cytotoxicity test indicated that the synthetic compounds showed no significant difference in three concentrations tested (5, 20, and 80 µg/ml), allowing cell viability not different from that assigned to the control, without the tested compounds. In this context, the development of DHPM derivatives brings an alternative and perspective on effectiveness of drugs as potential future antimicrobial agents.

Detection of SARS-CoV-2 virus using an alternative molecular method and evaluation of biochemical, hematological, inflammatory, and oxidative stress in healthcare professionals.

In early December 2019, an outbreak of coronavirus disease 2019 caused by a new strain of coronavirus (SARS-CoV-2), occurred in the city of Wuhan, Hubei Province, China. On January 30, 2020, the World Health Organization (WHO) declared the outbreak a public health emergency of international concern. Since then, frontline healthcare professionals have been experiencing extremely stressful situations and damage to their physical and mental health. These adverse conditions cause stress and biochemical, hematological, and inflammatory changes, as well as oxidative damage, and could be potentially detrimental to the health of the individual. The study population consisted of frontline health professionals working in BHU in a city in southern Brazil. Among the 45 participants, two were infected with the SARS-CoV-2 virus and were diagnosed using immunochromatographic tests such as salivary RT-LAMP and qRT-PCR. We also evaluated biochemical, hematological, inflammatory, and oxidative stress markers in the participants. The infected professionals (CoV-2-Prof) showed a significant increase in the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), cholesterol, lactic dehydrogenase, lymphocytes, and monocytes. In this group, the levels of uric acid, triglycerides, leukocytes, neutrophils, hemoglobin, hematocrit, and platelets decreased. In the group of uninfected professionals (NoCoV-2-Prof), significant increase in HDL levels and the percentages of eosinophils and monocytes, was observed. Further, in this group, uric acid, LDH, triglyceride, and cholesterol levels, and the hematocrit count and mean corpuscular volume were significantly reduced. Both groups showed significant inflammatory activity with changes in the levels of C-reactive protein and mucoprotein. The NoCoV-2-Prof group showed significantly elevated plasma cortisol levels. To our kowledge, this study is the first to report the use of the RT-LAMP method with the saliva samples of health professionals, to evalute of SARS-CoV-2.

Retentive efficacy, antimicrobial and cytotoxicity comparisons between different types of commercial and experimental denture adhesives with antifungal action.

The effect of the addition of nystatin and an alternative antifungal derived from pyrazoles in different commercial denture adhesives on their retentive efficacy, cytotoxicity and antimicrobial activity against Candida albicans was evaluated. Commercial denture adhesives were prepared with the inclusion of nystatin and 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamide (pyrazole) in three concentrations: 23.78 %w/w, 3.02 %w/w, and 0.31 %w/w (0.015 g, 0.0015 g, and 0.00015 g, respectively). The retentive efficacy was tested observing the influence of the medium, type of commercial denture type and the test condition (dipping). The antifungal action through disk diffusion and direct contact tests at 1, 4, 8 and 12 h and cytotoxic activity was evaluated in mouse fibroblasts (NIH/3T3) by the MTT reduction colorimetric assay. The addition of pyrazole and nystatin in commercial denture adhesives did not affect retentive efficacy rates and enhanced antifungal actions against Candida albicans. Results show a possibility of using denture adhesives as a delivery system for commercial antifungals (Nystatin) or pyrazole, with the second concentration (1,560 µg-3.02 %w/w) as the most efficient.

Exposure of tilapia (Oreochromis niloticus) to the antibiotic florfenicol in water: determination of the bioconcentration factor and the withdrawal period.

The demand for healthier foods with high nutritional value has resulted in intensive fish farming. In this production system, high-frequency infections occur, and antibiotics are administrated for control. Only two antibiotics are allowed for use in Brazilian aquaculture, one of which is florfenicol. In this work, a bioconcentration assay was performed to assess the accumulation of florfenicol in the muscle of Nile tilapia (Oreochromis niloticus). Tilapia was evaluated as it is the most produced fish species in Brazil. The fish were exposed to florfenicol at a nominal concentration of 10 mg/L, through the water. Muscle and water were collected at 0, 1.5, 3, 6, 24, and 48 h during the exposure phase and at 1.5, 3, 6, 24, 48, and 120 h during the depuration phase. Quantification was performed using an LC-MS/MS. The results showed rapid absorption and elimination of the antibiotic (half-life, t1/2 = 5 h), with low potential for accumulation of florfenicol in tilapia muscles. The study was performed to determine the bioconcentration factor (BCF) and withdrawal period of florfenicol, being 0.05 mL/µg and 1.8 h, respectively. The results contribute to set protocols for the safe use of florfenicol in tilapia transport, avoiding residues in fish that may pose risks to human health.

Avaliação de risco ecológico do óleo essencial de Piper aduncum em organismos não alvo / Ecological risk assessment of Piper aduncum essential oil in non-target organisms

Uma possível alternativa ao uso de fármacos veterinários no tratamento e prevenção de doenças na piscicultura é o uso do óleo essencial de Piper aduncum. No entanto, são necessários dados ecotoxicológicos para garantir seu uso apropriado sem causar efeitos adversos a organismos não alvo. Esta informação é relevante, pois esse óleo essencial é descrito como tendo atividades inseticidas, moluscicidas e citotóxicas, possivelmente associadas à sua composição química. Assim, o objetivo deste estudo foi avaliar a ecotoxicidade do óleo essencial de P. aduncum para cinco organismos-teste, usando o método estatístico da Distribuição da Sensibilidade das Espécies (SSD). A composição química do óleo essencial foi caracterizada por cromatografia gasosa acoplada a espectrometria de massa (GC-MS) e cromatografia gasosa com detector de ionização de chama (GC-FID), para fins de identificação e quantificação, respectivamente. O principal componente (75,5%) do óleo essencial foi o dilapiol. A concentração perigosa para 5% de espécies biológicas (HC5) foi calculada com um nível de proteção de 95%, resultando em um valor de 0,47 mg L-1 (com intervalo de confiança de 50% = 0,028 - 1,19 mg L-1). A faixa de concentração relacionada aos níveis de proteção para comunidades aquáticas (concentração sem efeito previsto - PNEC) foi calculada através da aplicação de fatores de segurança ao valor de HC5. Os parâmetros de ecotoxicidade indicaram que o óleo essencial de P. aduncum pode ser usado com segurança em corpos d'água se a concentração for igual ou inferior a 0,09 mg L-1.(AU)

Epitope-resolved serology test differentiates the clinical outcome of COVID-19 and identifies defects in antibody response in SARS-CoV-2 variants

BACKGROUNDThe role of humoral immunity in the coronavirus disease 2019 (COVID-19) is not fully understood owing, in large part, to the complexity of antibodies produced in response to the SARS-CoV-2 infection. There is a pressing need for serology tests to assess patient-specific antibody response and predict clinical outcome. METHODSUsing SARS-CoV-2 proteome and peptide microarrays, we screened 146 COVID-19 patients plasma samples to identify antigens and epitopes. This enabled us to develop a master epitope array and an epitope-specific agglutination assay to gauge antibody responses systematically and with high resolution. RESULTSWe identified 54 linear epitopes from the Spike (S) and Nucleocapsid (N) protein and showed that epitopes enabled higher resolution antibody profiling than protein antigens. Specifically, we found that antibody responses to the S(811-825), S(881-895) and N(156-170) epitopes negatively or positively correlated with clinical severity or patient survival. Moreover, we found that the P681H and S235F mutations associated with the coronavirus variant B.1.1.7 altered the specificity of the corresponding epitopes. CONCLUSIONSEpitope-resolved antibody testing not only offers a high-resolution alternative to conventional immunoassays to delineate the complex humoral immunity to SARS-CoV-2 and differentiate between neutralizing and non-neutralizing antibodies, it may also be used as predictor of clinical outcome. The epitope peptides can be readily modified to detect antibodies against variants in both the peptide array and latex agglutination formats. FUNDINGOntario Research Fund (ORF)-COVID-19 Rapid Research Fund, the Toronto COVID-19 Action Fund, Western University, the Lawson Health Research Institute, the London Health Sciences Foundation, and the AMOSO Innovation Fund.

Guidelines for prophylaxis and anti-thrombotic treatment for patients with COVID-19. Consensus of the Latin American Cooperative Group on Hemostasis and Thrombosis (CLAHT) / Guía de profilaxia y tratamiento antitrombótico para pacientes con COVID-19. Consenso del Grupo Cooperativo Latinoamericano en Hemostasia y Trombosis (CLAHT)

Coagulopathy and thrombosis associated with coronavirus disease 2019 (COVID-19) represent a major issue in the management of this disease. In the past months, clinical studies have demonstrated that COVID-19 patients present with a particular hypercoagulable state, in which a markedly increased D-dimer concomitant with increased levels of fibrinogen are observed. This hypercoagulable state leads to an increased risk of thrombosis, which seems to be higher among those patients with critical symptoms of COVID-19. The best therapeutic approach to prevent thrombotic events in COVID-19 has not been determined yet and several questions regarding thromboprophylaxis therapy, such as the time to initiate anticoagulation, type of anticoagulant and dose regimen, have emerged among physicians. To address these concerns, several medical societies have published position papers to provide the opinion of thrombosis experts on the management of coagulopathy and thrombosis associated with COVID-19. In line with this, the Latin America Cooperative Group of Hemostasis and Thrombosis (Grupo CLAHT) has constituted a panel of experts in thrombosis and hemostasis to discuss the available data on this topic. The aim of this review is to summarize the current evidence regarding hemostatic impairment and thrombotic risk in COVID-19 and to provide a carefully revised opinion of Latin American experts on the thromboprophylaxis and management of thrombotic events and coagulopathy in patients with suspected COVID-19.

La coagulopatía y la trombosis asociadas a la enfermedad por coronavirus 2019 (COVID-19) representan un problema importante en el manejo de esta enfermedad. Los estudios clínicos de los últimos meses han demostrado que los pacientes con COVID-19 presentan un estado de hipercoagulabilidad particular, en el que se observa un aumento notable del dímero D concomitante con niveles elevados de fibrinógeno. El estado de hipercoagulabilidad conduce a un mayor riesgo de trombosis, que parece ser mayor entre aquellos pacientes con síntomas críticos de COVID-19. El mejor enfoque terapéutico para prevenir los eventos trombóticos en esta nueva enfermedad aún no se ha determinado y han surgido varias preguntas con respecto a la tromboprofilaxia, como el momento adecuado para iniciar la anticoagulación, el tipo de anticoagulante y el régimen de dosis. Para abordar estas preocupaciones, varias sociedades médicas han publicado artículos de posición para brindar la opinión de expertos en trombosis sobre el manejo de la coagulopatía y trombosis asociadas a COVID-19. Grupo Cooperativo Latinoamericano de Hemostasia y Trombosis (Grupo CLAHT) ha convocado a un panel de expertos en trombosis y hemostasia para discutir los datos disponibles sobre este tema. El objetivo de esta revisión es resumir la evidencia actual con respecto al deterioro hemostático y el riesgo trombótico en el COVID-19 y proporcionar una opinión cuidadosamente revisada de los expertos latinoamericanos sobre la tromboprofilaxis y el manejo de eventos trombóticos y coagulopatía en pacientes con sospecha de COVID-19.

Risk assessment and acute toxicological effects of atrazine on Nile tilapia larvae after stress.

The present study aimed to evaluate the risk assessment, median lethal concentration LC50-96h, development, and mortality of Nile tilapia Oreochromis niloticus larvae exposed to atrazine after stress management. An LC50-96h trial was carried out using fish (n = 147; 8.5 ± 1.0 mg; seven larvae/aquarium), which were allocated randomly in 21 aquaria (1 L) and exposed to five concentrations of atrazine: 2, 4, 8, 16, and 32 mg L-1 plus one control (without herbicide) and a control with a solubility adjuvant (acetone). Temperature, pH, dissolved oxygen, conductivity, and total ammonia were measured daily. In addition, a stress test was performed with fish (n = 150; 17.9 ± 1.7 mg; 10 larvae/aquarium) submitted to air exposition (five minutes) and posteriorly distributed randomly in 15 aquaria (1 L), and exposed to atrazine at 0.18, 6, 12, and 18 mg L-1. The LC50-96h of atrazine for Nile tilapia larvae was 17.87 mg L-1. Significant differences (P < 0.05) were found for weight and final length, pH, and dissolved oxygen that was responsive to the increased levels of herbicide. Larvae mortality post-stress was registered to 6, 12, and 18 mg L-1 of atrazine, and was more critical at 24 h. The increased doses of atrazine used in LC50-96h test depressed the development of Nile tilapia larvae. Fish submitted to stress (air exposition) and exposed to sub-lethal doses of atrazine showed significant mortality, indicating that stressors may increase the toxic effect of atrazine for Nile tilapia larvae. On the other hand, based on risk assessment atrazine can be classified as herbicide with low toxicity for Nile tilapia larvae and low toxicological risk.

Bioprospection of novel synthetic monocurcuminoids: Antioxidant, antimicrobial, and in vitro cytotoxic activities.

The irrational use of medications has increased the incidence of microbial infections, which are a major threat to public health. Moreover, conventional therapeutic strategies are starting to become ineffective to treat these infections. Hence, there is a need to develop and characterize novel antimicrobial compounds. Phytochemicals are emerging as a safe and accessible alternative to conventional therapeutics for treating infectious diseases. Curcumin is extracted from the dried rhizome of the spice turmeric (Curcuma longa (Zingiberaceae)). However, the bioavailability of curcumin is low owing to its lipophilic property and thus has a low therapeutic efficacy in the host. A previous study synthesized structural variants of curcumin, which are called monocurcuminoids (CNs). CNs are synthesized based on the chemical structure of curcumin with only one methyl bridge. The biological activities of four previously synthesized CNs (CN59, CN63, CN67, and CN77), curcumin, and turmeric powder were examined in this study. Gas chromatography-tandem mass spectrometry analysis of curcumin and turmeric powder revealed similar peaks, which indicated the presence of curcumin in turmeric powder. The antioxidant activity of the test compounds was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays. The ABTS radical scavenging activities of the test compounds were similar to those of vitamin C. The minimum inhibitory concentration (MIC) values of the test compounds against seven microbial strains were in the range of 4.06-150 µg/mL. The MIC value was equal to minimum bactericidal concentration value for CN63 (150 µg/mL) and CN67 (120 µg/mL) against Staphylococcus aureus. The treatment combination of CN77 (8.75 or 4.37 µg/mL) and turmeric powder (9.37 or 4.68 µg/mL) exerted synergistic growth-inhibiting effects on Aeromonas hydrophila, Candida albicans, and Pseudomonas aeruginosa. Photodynamic therapy using 2X MIC of CN59 decreased the growth of Enterococcus faecalis by 4.18-fold compared to the control group and completely inhibited the growth of Escherichia coli. The results of the hemolytic assay revealed that the test compounds were not cytotoxic with half-maximal inhibitory concentration values ranging from 49.65-130.9 µM. The anticoagulant activity of most compounds was comparable to that of warfarin but higher than that of heparin. This indicated that these compounds target the intrinsic coagulation pathway. These results demonstrated that these CNs are a safe and promising alternative for curcumin.

Evaluation of health and environmental risks for juvenile tilapia (Oreochromis niloticus) exposed to florfenicol.

Intensive fish cultivation has a high incidence of infection, which is often controlled by administering antibiotics. Florfenicol (FF) is one of the two antimicrobial drugs permitted for aquaculture in Brazil. Due to their intensive use, potentially harmful effects on aquatic organisms are of great concern. In this sense, we investigated whether the presence of FF in cultivation water could change the health parameters of Nile tilapia. For this, we evaluated hemoglobin, hematocrit, mean corpuscular hemoglobin (MCHC) concentration, mean corpuscular volume (MCV), total plasma protein (TPP), number of circulating red blood cells and leukocytes, as lipid peroxidation levels, catalase activity and glutathione S-transferase activity of fish exposed to 11.72 mg L-1 of FF in water for 48 h. The fish were divided into two groups: Nile tilapia in water with FF or without FF (control). Exposure to FF in cultivation water for a short period didn't change the hematological variables analyzed, but caused changes in liver ROS (Reactive oxygen species) markers of the Nile tilapia, which was revealed by lipid peroxidation levels, catalase activity, and glutathione S-transferase. The 48h exposure period was enough to induce oxidative stress in hepatocytes, causing cellular oxidative damage. Therefore, the antibiotic florfenicol may cause toxicity to organisms and aquatic ecosystems, even at a sublethal concentrations near 1/100 LC50-48h for fish species.