Otávio Valério de Carvalho

The thiopurine nucleoside analogue 6-methylmercaptopurine riboside (6MMPr) effectively blocks zika virus replication

Since the emergence of Zika virus (ZIKV) in Brazil in 2015, 48 countries and territories in the Americas have confirmed autochthonous cases of disease caused by the virus. ZIKV-associated neurological manifestations and congenital defects make the development of safe and effective antivirals against ZIKV of utmost importance. Here we evaluated the antiviral activity of 6-methylmercaptopurine riboside (6MMPr), a thiopurine nucleoside analogue derived from the prodrug azathioprine, against the epidemic ZIKV strain circulating in Brazil. In all of the assays, an epithelial (Vero) and a human neuronal (SH-SY5Y) cell line were used to evaluate the cytotoxicity and effective concentrations of 6MMPr against ZIKV. Levels of ZIKV-RNA, viral infectious titre and the percentage of infected cells in the presence or absence of 6MMPr were used to determine antiviral efficacy. 6MMPr decreased ZIKV production by >99% in both cell lines in a dose- and time-dependent manner. Interestingly, 6MMPr was 1.6 times less toxic to SH-SY5Y cells compared with Vero cells, presenting a 50% cytotoxic concentrations (CC50) of 460.3 µM and 291 µM, respectively. The selectivity index of 6MMPr for Vero and SH-SY5Y cells was 11.9 and 22.7, respectively, highlighting the safety profile of the drug to neuronal cells. Taken together, these results identify, for the first time, the thiopurine nucleoside analogue 6MMPr as a promising antiviral candidate against ZIKV that warrants further in vivo evaluation.

Evaluation of the antiviral activities of Bacharis dracunculifolia and quercetin on Equid herpesvirus 1 in a murine model

Equid herpesvirus 1 (EHV-1) is a pathogen of high economic importance in equine breeding operations around the world. EHV-1 infection causes respiratory, neurologic and reproductive disease. The absence of an efficient therapy has caught the attention of the scientific community and the therapeutic activities of natural products with its antivirals effects might be effective for the diseases treatment. Herein it was evaluated the prophylactic and therapeutic potential of quercetin and ethanolic extracts of Bacharis dracunculifolia formulations compared to Penciclovir® in an in vivo EHV-1 infection model. Six to seven-week-old female C57BL/6 mice were randomly organized into fifteen groups with six animals each. Ex-1 represents the treatment post-challenge groups to assess morbidity, mortality and weight variation. Ex-2 represents the animals that received treatment for 5 days post-challenge for lesion evaluation. In Ex-3 animals were treated prior to viral challenge to assess morbidity, mortality and weight variation. All mice in the treatment groups were challenged by intranasal inoculation of 3.0 × 105 TCID50 EHV-1. The quercetin and B. dracunculifolia treatment decreased morbimortality in post-challenge treatment (Ex-1) and EHV-1 related lesions (Ex-2). Treatment prior to viral challenge (Ex-3) did not show any significant results. Based on the results of the present study, both tested formulations are promising antiviral agents for the treatment of EHV-1 infection.

Revisiting Key Entry Routes of Human Epidemic Arboviruses into the Mainland Americas through Large-Scale Phylogenomics

The rapid worldwide spread of chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses have raised great international concern. Knowledge about the entry routes and geographic expansion of these arboviruses to the mainland Americas remain incomplete and controversial. Epidemics caused by arboviruses continue to cause socioeconomic burden globally, particularly in countries where vector control is difficult due to climatic or infrastructure factors. Understanding how the virus circulates and moves from one country to another is of paramount importance to assist government and health officials in anticipating future epidemics, as well as to take steps to help control or mitigate the spread of the virus. Through the analyses of the sequences of arbovirus genomes collected at different locations over time, we identified patterns of accumulated mutations, being able to trace routes of dispersion of these viruses. Here, we applied robust phylogenomic methods to trace the evolutionary dynamics of these arboviruses with special focus on Brazil, the epicenter of these triple epidemics. Our results show that CHIKV, DENV-1–4, and ZIKV followed a similar path prior to their first introductions into the mainland Americas, underscoring the need for systematic arboviral surveillance at major entry points of human population movement between countries such as airports and seaports.

6-methylmercaptopurine riboside, a thiopurine nucleoside with antiviral activity against canine distemper virus in vitro

BackgroundCanine distemper (CD) is a widespread infectious disease that can severely impact a variety of species in the order Carnivora, as well as non-carnivore species such as non-human primates. Despite large-scale vaccination campaigns, several fatal outbreaks have been reported in wild and domestic carnivore populations. This, in association with expansion of the disease host range and the development of vaccine-escape strains, has contributed to an increased demand for therapeutic strategies synergizing with vaccine programs for effectively controlling canine distemper. 6-methylmercaptopurine riboside (6MMPr) is a modified thiopurine nucleoside with known antiviral properties against certain RNA viruses.MethodsWe tested the inhibitory effects of 6MMPr against a wild-type CDV strain infection in cell culture. We measured infectious particle production and viral RNA levels in treated and untreated CDV-infected cells. Ribavirin (RIB) was used as a positive control.ResultsHere, we report for the first time the antiviral effects of 6MMPr against canine distemper virus (CDV) in vitro. 6MMPr was able to reduce viral RNA levels and to inhibit the production of infectious CDV particles. The therapeutic selectivity of 6MMPr was approximately six times higher than that of ribavirin.ConclusionOur results indicate that 6MMPr has high anti-CDV potential and warrants further testing against other paramyxoviruses, as well as clinical testing of the compound against CDV.

Designing Ti6Al4V doped hydroxyapatite structures for dental applications

T study reports the preparation of the new drug carrier gel system based on poly (itaconic anhydride-co-3, 9-divinyl-2, 4, 8, 10-tetraoxaspiro (5.5) undecane) (PITAU) copolymer and hyaluronic acid (HA-PITAU). In relation with its composition PITAU has specific conformational structure owing to the unsaturated double bond of 3, 9-divinyl-2, 4, 8, 10-tetraoxaspiro (5.5) undecane comonomer and the spiroacetal moiety, giving macromolecular chains with network type structures. PITAU is biocompatible and biodegradable and present pH and temperature sensitivity. Itaconic anhydride (ITA) has been considered as an alternative to maleic anhydride for introducing polar functionality into polymers. Polymers based on ITA have not received as much attention as lactic acid derived materials. The composition was confirmed by FTIR spectra, evidencing the cross linking bridges between copolymer and hyaluronic acid. SEM microscopy and chemical imagining evidence the homogeneous porous structure of the new 3D network. NIR-chemical imaging technique proves the successful preparation of polymeric drug delivery system by using indomethacin (IND) as bioactive model substance. The dissolution data revealed the interdependence of the ratio between the two compounds and attaining optimum loading capacity. In vivo study demonstrated that HA_ PITAU and HA_ PITAU_IND determined similar blood parameters modifications and biochemical responses with distilled water, after intraperitoneal administration in mice. Systemic administration of the tested substances in mice did not modify their immune reactivity comparing with control group. All these results reveal a good in vivo biocompatibility. The bioactive compound caused a significant antinociceptive effect occurring after 60 minutes and lasts about 3 hours in tail flick test.R dystrophic epidermolysis bullosa (RDEB) has been defined as severe chronic skin fragility and caused by mutations in COL7A1, which encodes for the elastic structural protein type VII collagen (C7). The 8.9 Kb COL7A1 transcript is particularly a large sequence with many repeating units which makes it difficult to manipulate and package into viral systems. Therefore, the minicircle system is ideal for use with COL7A1, firstly to minimize the overall DNA construct size while secondly increasing the safety profile of the gene therapy. We successfully inserted COL7A1 into the parental plasmid MN512A1 and combined it with our highly efficient a non-viral vector (HPAE). HPAE-MC-COL7A1 polyplexes successfully produced significant levels of recombinant C7 with negligible cytotoxicity in RDEB-TA4 keratinocytes. Minimal effect was seen on primary keratinocyte metabolic health, even after multiple applications of HPAE polyplexes. Furthermore, in vivo transfection studies revealed that HPAE carrying MC-COL7A1 restores the expression of C7 along the basement membrane zone in a human RDEB graft mouse model after intradermal injection and topical application. Of the 7 animals treated, 5 were positive for recombinant C7, with all animals receiving 2 or more applications having strong positive signal. While further assessment is required to prove this approach is safe and well tolerated in the long term, HPAE-MC-COL7A1 polyplexes showed great promise as a potential therapeutic for RDEB.M play important roles to repair human tissue defect. In this work, human amniotic membrane (HAM) was decellularized and explored the efficacy as an implantable biological mesh. Surfactant, hypertonic saline, lipase and DNAase were used individually or collectively to remove all cell components and remain the extracellular matrix. Results of H&E and DAPI staining demonstrated that the method of surfactant and lipase combining with DNAase is the most effective treatment for HAM decellularization. Primary smooth muscle cells were seeded to evaluate the decellularized HAM’s (dHAM) in vitro cytocompatibility. The in vivo test was performed via implantation at rabbits’ uterus with clinic polypropylene mesh (PP) as the control. The results indicated that dHAM possessed good biocompatibility and will be a potential candidate for biological mesh.

Campanulotes compar (Burmeister, 1838) (Phthiraptera: Ischnocera) in chickens (Gallus gallus domesticus) from Rio Grande do Norte State, Brazil. The reemergence of an ectoparasite?

The importance of ectoparasites in the transmission of pathogens, as well as the variability of species from one region to another, motivated this notification of the ectoparasite lice Campanulotes compar in range chickens (Gallus gallus domesticus L.) reared in an extensive system in the city of Apodi, Rio Grande do Norte state, in the Northeast region of Brazil. The examined birds were infested with ten males and six females of C. compar. Thus, C. compar is recorded as parasitizing chickens in the state of Rio Grande do Norte after 77 years from its unique citation in the Southeast region of Brazil. We further discuss the possible risks of this finding.

First occurrence of Amblyomma ovale in the State of Rio Grande do Norte, Brazil

This study aims to report the occurrence of parasitism by Amblyomma ovale (Koch, 1844) in dogs in the municipality of Apodi, Rio Grande do Norte, Brazil. Specimens were identified as being one female and two males of A. ovale, besides; the animal was infested by five females of Rhipicephalus (Boophilus) microplus and seven females and three males of R. sanguineus. The finding of A. ovale confirms results in the literature that these ticks, reported in several species of wild carnivores, can also infect dogs in Brazil. The distribution of this tick species in several Brazilian states has already been confirmed, but this is the first report in the State of Rio Grande do Norte. This finding highlights the risk of the carrying of emerging and re-emerging pathogens to peridomestic hosts are as, either because of the frequency of these ticks in wild environments or the presence of infected wild animals near peridomestic environments, exposing domestic dogs to parasitism by A. ovale ticks and, therefore, to agents potentially carried by this ectoparasite.