THE SUSCEPTIBILITY OF RECENT ISOLATES OF Schistosoma mansoni TO PRAZIQUANTEL

Introduction: Schistosomiasis is a chronic disease caused by trematode flatworms of the genus Schistosoma and its control is dependent on a single drug, praziquantel (PZQ), but concerns over PZQ resistance have renewed interest in evaluating the in vitro susceptibility of recent isolates of Schistosoma mansoni to PZQ in comparison with well-established strains in the laboratory. Material and methods: The in vitro activity of PZQ (6.5-0.003 µg/mL) was evaluated in terms of mortality, reduced motor activity and ultrastructural alterations against S. mansoni. Results: After 3 h of incubation, PZQ, at 6.5 µg/mL, caused 100% mortality of all adult worms in the three types of recent isolates, while PZQ was inactive at concentrations of 0.08-0.003 µg/mL after 3 h of incubation. The results show that the SLM and Sotave isolates basically presented the same pattern of susceptibility, differing only in the concentration of 6.5 µg/mL, where deaths occurred from the range of 1.5 h in Sotave and just in the 3 h range of SLM. Additionally, this article presents ultrastructural evidence of rapid severe PZQ-induced surface membrane damage in S. mansoni after treatment with the drug, such as disintegration, sloughing, and erosion of the surface. Conclusion: According to these results, PZQ is very effective to induce tegument destruction of recent isolates of S. mansoni

In vitro evaluation of alkaline lignins as antiparasitic agents and their use as an excipient in the release of benznidazole

Copyright © 2023. Published by Elsevier B.V.The Amazon rainforest is considered the largest tropical timber reserve in the world. The management of native forests in the Amazon is one of the most sensitive geopolitical issues today, given its national and international dimension. In this work, we obtained and characterized physicochemical lignins extracted from branches and leaves of Protium puncticulatum and Scleronema micranthum. In addition, we evaluated in vitro its potential as an antioxidant, cytotoxic agent against animal cells and antiparasitic against promastigotes of Leishmania amazonensis, trypomastigotes of T. cruzi and against Plasmodium falciparum parasites sensitive and resistant to chloroquine. The results showed that the lignins obtained are of the GSH type and have higher levels of guaiacyl units. However, they show structural differences as shown by spectroscopic analysis and radar charts. As for biological activities, they showed antioxidant potential and low cytotoxicity against animal cells. Antileishmanial/trypanocidal assays have shown that lignins can inhibit the growth of promastigotes and trypomastigotes in vitro. The lignins in this study showed low anti-Plasmodium falciparum activity against susceptible strains of Plasmodium falciparum and were able to inhibit the growth of the chloroquine-resistant strain. And were not able to inhibit the growth of Schistosoma mansoni parasites. Finally, lignins proved to be promising excipients in the release of benznidazole. These findings show the potential of these lignins not yet studied to promote different biological activities.publishersversionpublishe

ULTRASTRUCTURAL CHANGES IN Schistosoma mansoni MALE WORMS AFTER in vitro INCUBATION WITH THE ESSENTIAL OIL OF Mentha x villosa Huds

Introduction: The essential oil Mentha x villosa (MVEO) has a wide range of actions, including antibacterial, antifungal, antiprotozoal and schistosomicidal actions. The present study aimed to investigate the ultrastructural changes of MVEO on the tegument of adult Schistosoma mansoni. Materials and Methods: Different concentrations of MVEO were tested on S. mansoni adult worms in vitro. Ultrastructural changes on the tegument of these adult worms were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results: The MVEO caused the death of all worms at 500 μg mL-1 after 24 h. After 24h of 500 μg mL-1 MVEO treatment, bubble lesions were observed over the entire body of worms and they presented loss of tubercles in some regions of the ventral portion. In the evaluation by TEM, S. mansoni adult worms treated with MVEO, 500 μg mL-1, presented changes in the tegument and vacuoles in the syncytial matrix region. Glycogen granules close to the muscle fibers were visible. Conclusion: The ability of MVEO to cause extensive ultrastructural damage to S. mansoni adult worms correlates with its schistosomicidal effects and confirms earlier findings with S. mansoni

Synthesis and biological evaluation of novel imidazolidine derivatives as candidates to schistosomicidal agents

Introduction: Schistosomiasis is an infectious parasitic disease caused by trematodes of the genus Schistosoma, which threatens at least 258 million people worldwide and its control is dependent on a single drug, praziquantel. The aim of this study was to evaluate the anti-Schistosoma mansoni activity in vitro of novel imidazolidine derivatives. Material and methods: We synthesized two novel imidazolidine derivatives: (LPSF/PTS10) (Z)-1-(2-chloro-6-fluorobenzyl)-4-(4-dimethylaminobenzylidene)-5-thioxoimidazolidin-2-one and (LPSF/PTS23) (Z)-1-(2-chloro-6-fluoro-benzyl)-5-thioxo-4-(2,4,6-trimethoxy-benzylidene)-imidazolidin-2-one. The structures of two compounds were determined by spectroscopic methods. During the biological assays, parameters such as motility, oviposition, mortality and analysis by Scanning Electron Microscopy were performed. Results: LPSF/PTS10 and LPSF/PTS23 were considered to be active in the separation of coupled pairs, mortality and to decrease the motor activity. In addition, LPSF/PTS23 induced ultrastructural alterations in worms, after 24 h of contact, causing extensive erosion over the entire body of the worms. Conclusion: The imidazolidine derivatives containing the trimetoxy and benzylidene halogens showed promising in vitro schistosomicidal activity

Aspectos relacionados com a positividade para a esquistossomose: estudo transversal em área de baixa prevalência do estado de Alagoas, 2020

Objective: To analyze aspects related to positivity for schistosomiasis in an area of ​​low prevalence in Brazil. Methods: Cross-sectional study, carried out in the first half of 2020, where proportion of positivity was analyzed according to the number of Kato-Katz slides, the diagnostic performance of the test and the creation of a positivity estimation factor from the data of the Information from the Schistosomiasis Surveillance and Control Program (SISPCE). Results: 2,088 slides from 348 individuals were analyzed, with proportion of positivity of 11.8%, 26.7% and 31.0% for 1, 4 and 6 slides analyzed, respectively. There was excellent agreement (Kappa = 0.91) between the reading of 4 and 6 slides. An underreporting of 2.1 times was estimated in the SISPCE data. Conclusion: Increasing the number of blades increased the positivity of Kato-Katz, which can contribute to maximize the control of the disease as a public health problem.Objetivo: Analisar aspectos relacionados com a positividade para esquistossomose em área de baixa prevalência, no Brasil. Métodos: Estudo transversal, realizado no primeiro semestre de 2020, quando foram analisadas a proporção de positividade, em função do número de lâminas de Kato-Katz, o desempenho diagnóstico do teste e a estimação da positividade a partir dos dados do Sistema de Informação do Programa de Vigilância e Controle da Esquistossomose (SISPCE). Resultados: Foram analisadas 2.088 lâminas de 348 indivíduos, sendo a proporção de positividade de 11,8%, 26,7% e 31,0% para 1, 4 e 6 lâminas analisadas, respectivamente. Houve concordância excelente (índice Kappa = 0,91) na comparação entre as leituras de 4 e 6 lâminas. Foi estimada subnotificação de 2,1 vezes nos dados do SISPCE. Conclusão: Ampliar o número de lâminas aumentou a positividade do Kato-Katz, o que pode contribuir para maximizar o controle da doença enquanto problema de Saúde Pública

Cotesia flavipes (CAM) (Hymenoptera: Braconidae) Supresses Immune Responses In Diatraea flavipennella (BOX) (Lepidoptera: Crambidae)

The present research aimed to elucidate which aspects of immune responses in Diatraea flavipennella are suppressed by the parasitoid Cotesia flavipes, thus, ensuring parasitism success. We investigated the presence of apoptosis in fat body cells through the TUNEL technique. According to the results, reduced levels of nitric oxide and phenoloxidase activity were observed in larvae parasitized for three days, and reduced total number of hemocytes, after three and seven days. An increase in plasmatocytes and decrease in spherulocytes numbers were observed in the differential count on the third day of parasitism. The number of melanized microspheres in parasitized larvae was low and indicated less intense melanization. The ultrastructural analysis confirmed the immunosuppressive effect of C. flavipes on the encapsulation response of D. flavipennella because only the formation of hemocytes capsules, adhered to the microspheres' surface, was evidenced in non-parasitized caterpillars. The effect of parasitism was also recorded on the third day with the presence of hemocytes and apoptosis in fat body cells, including aspects of degeneration in the latter. We concluded that C. flavipes suppresses cellular and humoral immunological responses in D. flavipennella and drastically affects the host's fat tissue