In Vitro Validation of Antiparasitic Activity of PLA-Nanoparticles of Sodium Diethyldithiocarbamate against Trypanosoma cruzi

Funding Information: This research was funded by Global Health and Tropical Medicine: Grant number IHMT-UID/multi/04413/2013 and Grant number PTDC/CVT-CVT/28908/2017, FCT-Portugal.We would like to thank João Aristeu da Rosa and Aline Rimodi Rimeiro at UNESP (Universidade Estadual de São Paulo) Araraquara (Brazil) for offering four different strains of T. cruzi. JWFO and MFAS give thanks to their financial support (PhD and post-doctoral fellowships) provided by Capes/Brazil; MSS, AASJ, and HAOR give thanks to CNPq/Brazil for the Research Grant (Bolsa de Produtividade). We would also like to thank the Department of Materials Engineering at UFRN for affording us the use of their scanning electron microscope, and the Department of Biochemistry at UFRN for affording us the use of their culture room. We thank Laysa Ohana for reviewing and editing the English version of the manuscript. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Trypanosoma cruzi is a protozoan parasite responsible for Chagas disease, which affects millions around the world and is not treatable in its chronic stage. Sodium diethyldithiocarbamate is a compound belonging to the carbamate class and, in a previous study, demonstrated high efficacy against T. cruzi, showing itself to be a promising compound for the treatment of Chagas disease. This study investigates the encapsulation of sodium diethyldithiocarbamate by poly-lactic acid in nanoparticles, a system of biodegradable nanoparticles that is capable of reducing the toxicity caused by free DETC against cells and maintaining the antiparasitic activity. The nanosystem PLA-DETC was fabricated using nanoprecipitation, and its physical characterization was measured via DLS, SEM, and AFM, demonstrating a small size around 168 nm and a zeta potential of around −19 mv. Furthermore, the toxicity was determined by MTT reduction against three cell lines (VERO, 3T3, and RAW), and when compared to free DETC, we observed a reduction in cell mortality, demonstrating the importance of DETC nanoencapsulation. In addition, the nanoparticles were stained with FITC and put in contact with cells for 24 h, followed by confirmation of whether the nanosystem was inside the cells. Lastly, the antiparasitic activity against different strains of T. cruzi in trypomastigote forms was determined by resazurin reduction and ROS production, which demonstrated high efficacy towards T. cruzi equal to that of free DETC.publishersversionpublishe

Antimicrobial Activity of Chitosan Oligosaccharides with Special Attention to Antiparasitic Potential

The global rise of infectious disease outbreaks and the progression of microbial resistance reinforce the importance of researching new biomolecules. Obtained from the hydrolysis of chitosan, chitooligosaccharides (COSs) have demonstrated several biological properties, including antimicrobial, and greater advantage over chitosan due to their higher solubility and lower viscosity. Despite the evidence of the biotechnological potential of COSs, their effects on trypanosomatids are still scarce. The objectives of this study were the enzymatic production, characterization, and in vitro evaluation of the cytotoxic, antibacterial, antifungal, and antiparasitic effects of COSs. NMR and mass spectrometry analyses indicated the presence of a mixture with 81% deacetylated COS and acetylated hexamers. COSs demonstrated no evidence of cytotoxicity upon 2 mg/mL. In addition, COSs showed interesting activity against bacteria and yeasts and a time-dependent parasitic inhibition. Scanning electron microscopy images indicated a parasite aggregation ability of COSs. Thus, the broad biological effect of COSs makes them a promising molecule for the biomedical industry.publishersversionpublishe

Structural assessment, toxicity, and increased antimicrobial activity

Scorpion venom is a rich source of biologically active components and various peptides with high-potential therapeutic use that have been characterized for their antimicrobial and antiproliferative activities. Stigmurin is a peptide identified from the Tityus stigmurus venom gland with high antibacterial and antiproliferative activities and low toxicity. Amino acid substitutions in peptides without a disulfide bridge sequence have been made with the aim of reducing their toxicity and increasing their biological activities. The purpose of this study was to evaluate the structural conformation and structural stability, as well as antimicrobial, antiproliferative, and hemolytic activities of two peptide analogs to Stigmurin, denominated StigA6 and StigA16. In silico analysis revealed the α-helix structure for both analog peptides, which was confirmed by circular dichroism. Data showed that the net charge and hydrophobic moment of the analog peptides were higher than those for Stigmurin, which can explain the increase in antimicrobial activity presented by them. Both analog peptides exhibited activity on cancerous cells similar to the native peptide; however, they were less toxic when tested on the normal cell line. These results reveal a potential biotechnological application of the analog peptides StigA6 and StigA16 as prototypes to new therapeutic agents.publishersversionpublishe

Effects of medullary decompression time in spinal cord injury: experimental study in rats

Com o objetivo de avaliar os efeitos do tempo da descompressão medular em 50 ratos, machos, da raça Wistar, criou-se um modelo experimental de compressão medular através da passagem de uma fita de tecido (cetim), que reduz em 30% o diâmetro do canal vertebral na região da coluna torácica após laminectomia (TIX E TX). Os animais foram distribuídos em cinco grupos com 10 ratos cada, sendo: grupo A, controle da técnica de exposição medular atraumática, sem lesão; grupo B, submetidos à compressão medular, seguida de descompressão cinco minutos após a lesão; nos grupos C e D, realizou-se o mesmo procedimento do grupo B, porém a descompressão ocorreu 24 e 72 horas após a compressão, respectivamente; os ratos do grupo E sofreram compressão, sem descompressão até o fim do experimento na quarta semana, quando os 50 ratos foram submetidos à eutanásia. Todos os animais com compressão (B, C, D e E) apresentaram paraplegia no pós-operatório imediato. A recuperação neurológica foi avaliada através do potencial evocado motor, da escala BBB de capacidade locomotora e do exame anatomopatológico do sítio da lesão. Observou-se relação direta entre o potencial de recuperação neurológica e o tempo da descompressão medular nos três métodos de avaliaçãoWith the objective of evaluating the effects of medullary decompression time in 50 male Wistar rats, an experimental model of medullary compression was created, through the insertion of a satin tape, which reduces in 30% the diameter of the vertebral canal at the region of the thoracic column after laminectomy (TIX and TX). The animals were distributed in five groups with 10 rats each, as follows: group A: control of the technique of atraumatic medullary exposure, with no lesion; group B, submitted to medullary compression, followed by decompression five minutes after the lesion; groups C and D underwent the same procedure, but decompression was performed 24 and 72 hours after compression, respectively; and finally, rats from group E underwent compression without decompression up to the end of the experiment on the 4th week, when all 50 rats were euthanized. All animals submitted to compression (groups B, C, D and E) presented paraplegia in the immediate post-operative period. The neurological recovery was evaluated through the motor-evoked potential of the BBB scale of locomotor capacity and anatomopathological examination of the lesion site. A direct correlation between the neurological recovery potential and time of medullary decompression was observed at the three evaluation method

Effects of medullary decompression time in spinal cord injury: experimental study in rats

Com o objetivo de avaliar os efeitos do tempo da descompressão medular em 50 ratos, machos, da raça Wistar, criou-se um modelo experimental de compressão medular através da passagem de uma fita de tecido (cetim), que reduz em 30% o diâmetro do canal vertebral na região da coluna torácica após laminectomia (TIX E TX). Os animais foram distribuídos em cinco grupos com 10 ratos cada, sendo: grupo A, controle da técnica de exposição medular atraumática, sem lesão; grupo B, submetidos à compressão medular, seguida de descompressão cinco minutos após a lesão; nos grupos C e D, realizou-se o mesmo procedimento do grupo B, porém a descompressão ocorreu 24 e 72 horas após a compressão, respectivamente; os ratos do grupo E sofreram compressão, sem descompressão até o fim do experimento na quarta semana, quando os 50 ratos foram submetidos à eutanásia. Todos os animais com compressão (B, C, D e E) apresentaram paraplegia no pós-operatório imediato. A recuperação neurológica foi avaliada através do potencial evocado motor, da escala BBB de capacidade locomotora e do exame anatomopatológico do sítio da lesão. Observou-se relação direta entre o potencial de recuperação neurológica e o tempo da descompressão medular nos três métodos de avaliaçãoWith the objective of evaluating the effects of medullary decompression time in 50 male Wistar rats, an experimental model of medullary compression was created, through the insertion of a satin tape, which reduces in 30% the diameter of the vertebral canal at the region of the thoracic column after laminectomy (TIX and TX). The animals were distributed in five groups with 10 rats each, as follows: group A: control of the technique of atraumatic medullary exposure, with no lesion; group B, submitted to medullary compression, followed by decompression five minutes after the lesion; groups C and D underwent the same procedure, but decompression was performed 24 and 72 hours after compression, respectively; and finally, rats from group E underwent compression without decompression up to the end of the experiment on the 4th week, when all 50 rats were euthanized. All animals submitted to compression (groups B, C, D and E) presented paraplegia in the immediate post-operative period. The neurological recovery was evaluated through the motor-evoked potential of the BBB scale of locomotor capacity and anatomopathological examination of the lesion site. A direct correlation between the neurological recovery potential and time of medullary decompression was observed at the three evaluation method

Padronização da técnica para captação do potencial evocado motor em ratos através da estimulação elétrica transcraniana

Os autores demonstram experimentalmente a padronização da técnica para obtenção do potencial evocado motor em ratos através da estimulação elétrica transcraniana. Foram utilizados 50 ratos Wistar devidamente anestesiados e preparados de acordo com as normas vigentes no Laboratório de Estudos do Traumatismo Raquimedular e Nervos Periféricos do Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina de São Paulo. A latência mínima média das respostas dos membros superiores foi de 2,5 ms e de membros inferiores foi de 6,5 ms. A amplitude média das respostas foi de 3,0 mV e de 2,5 mV nos membros superiores e membros inferiores, respectivamente. Os autores concluem que a técnica para captação do potencial evocado motor em ratos apresentada neste estudo é eficaz na análise da evolução eletrofisiológica da lesão medular, inédita no nosso meio, podendo ser reproduzida de modo simples, além de apresentar padrões de qualidade e aplicabilidade semelhantes aos observados na literatura mundial

Estudo da mortalidade na fratura do fêmur proximal em idosos Study of the proximal femoral fractures mortatlity in elderly patients

Foi feito um estudo de revisão sobre a mortalidade na fratura do fêmur proximal em idosos com base nas publicações mais relevantes do período de 1998 a 2002. Foram incluídos 25 artigos relacionados ao assunto, selecionados com base nos bancos de dados Medline e Cochrane, totalizando 24.062 pacientes com mais de 60 anos de idade, que tiveram fratura do fêmur proximal. Quatorze estudos foram prospectivos, oito retrospectivos e três revisões sistemáticas. As taxas médias de mortalidade foram de 5,5% durante a internação hospitalar, 4,7% ao fim de um mês de seguimento, 11,9% com três meses, 10,8% com seis meses, 19,2% com um ano e 24,9% com dois anos. Foram identificados quatro fatores intimamente relacionados com uma maior mortalidade nestes pacientes: idade avançada, grande número de doenças associadas, sexo masculino e presença de deficiências cognitivas. Outros fatores mostraram uma fraca correlação com a mortalidade como capacidade deambulatória prévia, índice de risco anestésico da Sociedade Americana de Anestesia (ASA), anemia, hipoalbuminemia, linfopenia e existência de AVC prévio. Os fatores como tempo prévio à cirurgia, tipo de anestesia utilizada e tipo de osteossíntese empregada não mostraram ter interferência.<br>A revision study was performed on the proximal femoral fractures mortality in elderly patients, based on the most relevant publications during the 1998 to 2002 period. Twenty-five articles related to the subject were included, selected from the Medline and Cochrane databases, totaling 24.062 patients over the age of 60 years, with fracture of the proximal femur. There were 14 prospective trials, 8 retrospective and 3 were systematic reviews. The mean in-hospital mortality was 5,5%, 1-month mortality 4,7%, 3-months 11,9%, 6-months 10,8%, 1-year 19,2% and 2-years 24,9%. Four factors were identified in these patients closely related with a larger number of deaths: advanced age, polymorbidity, male gender and the presence of cognitive impairment. Other factors, such as a pre-fracture walking ability, ASA score, hemoglobin level, albumin level, lymphocyte count and a previous stroke demonstrated poor correlation with mortality. Finally, factors like time-to-surgery, anesthetic techniques and type of osteosynthesis, had no effect on mortality

Aspidosperma pyrifolium Has Anti-Inflammatory Properties: An Experimental Study in Mice with Peritonitis Induced by Tityus serrulatus Venom or Carrageenan

Scorpions of the genus Tityus are responsible for the majority of envenomation in Brazil, the Tityus serrulatus species being the most common and dangerous in South America. In this approach, we have investigated the ability of the aqueous extract from the leaves of Aspidosperma pyrifolium in reducing carrageenan-induced inflammation and the inflammation induced by T. serrulatus envenomation in mice. We also evaluated the cytotoxic effects of this extract, using the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl-2H-tetrazolium (MTT) assay and the results revealed that the extract is safe. Analysis by High Performance Liquid Chromatography coupled with Diode Array Detector (HPLC-DAD) and Liquid Chromatography Coupled with Mass Spectrometry with Diode Array Detection (LC-DAD-MS) showed one major chemical component, the flavonoid rutin and phenolics compounds. For in vivo studies in carrageenan-induced peritonitis model, mice received extracts, dexamethasone, rutin or saline, before administration of carrageenan. For venom-induced inflammation model, animals received T. serrulatus venom and were, simultaneously, treated with extracts, antivenom, rutin or saline. The extract and rutin showed a reduction in the cell migration into the peritoneal cavity, and in the same way the envenomated animals also showed reduction of edema, inflammatory cell infiltration and vasodilation in lungs. This is an original study revealing the potential action of A. pyrifolium against inflammation caused by Tityus serrulatus venom and carrageenan, revealing that this extract and its bioactive molecules, specifically rutin, may present potential anti-inflammatory application