Alexandre Da Silva

Dr. Alexandre Da Silva


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2011 in Journal of Virological Methods
Verified
Journal Article
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VPVanessa de Paula
Vanessa de Paula
ASAlexandre Da Silva
Alexandre Da Silva
GBGentil Arthur Bentes
Gentil Arthur Bentes
EIEzio Tavares Iff
Ezio Tavares Iff
MSMaria Eduarda Monteiro Silva
Maria Eduarda Monteiro Silva
MPMarcelo Alves Pinto
Marcelo Alves Pinto

4 September 2019 in BMC Infectious Diseases
Verified
Journal Article
Open access
PDF file
JRJéssica Vasques Raposo
Jéssica Vasques Raposo
AAArthur Daniel Rocha Alves
Arthur Daniel Rocha Alves
ASAlexandre Da Silva
Alexandre Da Silva
DSDamião Carlos dos Santos
Damião Carlos dos Santos
JMJuliana Gil Melgaço
Juliana Gil Melgaço
VPVanessa de Paula
Vanessa de Paula
The etiology of acute liver failure (ALF) is often unknown and reported to be associated with herpesviruses in a number of cases. In this study, we examined for betaherpesviruses infections in patients with ALF of unknown etiology using a multiplex qPCR to Betaherpesviruses subfamily. Liver explant and serum samples from 27 patients with ALF of unknown etiology were analyzed with the aid of multiplex qPCR to identify betaherpesviruses. All positive samples were sequenced to confirm herpes infection and liver enzyme levels evaluated. Betaherpesviruses infection was effectively detected using multiplex qPCR. Six (22%) HHV-6, one (3%) HCMV and two (7%) dual infections (one with HHV-7/HHV-6, and the other with HHV-7/ HCMV). Interestingly, HHV-7 was only detected in the presence of other betaherpesviruses. Sequencing information confirmed betaherpesviruses infection. High hepatic enzyme levels and INR values> 1.5 were determined in all betaherpesvirus-positive patients. Multiplex qPCR facilitated efficient quantification, indicating that differentiation between betaherpesviruses is possible with the sole use of real-time PCR. Liver explant and serum samples were positive for some betaherpesviruses, and coinfection of HHV-7 with HHV-6 and HCMV was additionally detected. Based on these results, we propose that ALF patients should be screened for the presence of betaherpesviruses.

1 April 2015 in Antiviral Therapy
Verified
Journal Article
Closed access
ASAlexandre Da Silva
Alexandre Da Silva
JRJéssica V Raposo
Jéssica V Raposo
TPTiago Pereira
Tiago Pereira
MPMarcelo A Pinto
Marcelo A Pinto
VPVanessa de Paula
Vanessa de Paula
Background: Herpetic encephalitis (HSE) is caused mainly by herpes simplex virus type 1 (HSV-1) with an annual incidence of 1–4 cases/million inhabitants. Currently, HSE treatment faces difficulties such as the use of antivirals with elevated toxicity, metabolic side effects and HSV-1 resistance. An alternative to antivirals is the use of small interfering RNA (siRNA) as a viral replication inhibitor. In this work, siRNA targeting the UL-39 region was evaluated for HSE treatment in vivo. Methods: BALB/c mice were inoculated with HSV-1 and treated with siRNA. The treatment was evaluated through kinetics of HSV-1 replication inhibition, number of siRNA doses administered and treatment with siRNA plus acyclovir. All groups were evaluated for signs of HSE, mortality and HSV-1 replication inhibition. Results: The treated group of the kinetic experiment demonstrated a reduction of HSE signs and an HSV-1 replication inhibition of 43.6–99.9% in the brain and 53–98% in trigeminal ganglia (TG). Animals treated with one or two doses of siRNA had a prolonged survival time, reduced clinical signs of HSE and HSV-1 replication inhibition of 67.7% in brains and 85.7% in TG of animals treated with two doses of siRNA. Also, animals treated with siRNA plus acyclovir demonstrated reduced signs of HSE and mortality, as well as HSV-1 replication inhibition in the brain (83.2%) and TG (74.5%). Conclusions: These findings demonstrated that siRNA was capable of reducing HSE clinical signs, prolonging survival time and inhibiting HSV-1 replication in mice. Thus, siRNA can be a potential alternative to the standard HSE treatment especially to reduce clinical signs and extend survival time in vivo.

9 September 2022 in Viruses
Verified
Journal Article
Open access
PDF file
GBGentil Arthur Bentes
Gentil Arthur Bentes
NLNatália Maria Lanzarini
Natália Maria Lanzarini
JGJuliana Rodrigues Guimarães
Juliana Rodrigues Guimarães
MHMarcos Bryan Heinemann
Marcos Bryan Heinemann
EVEduardo de Mello Volotão
Eduardo de Mello Volotão
MPMarcelo Alves Pinto
Marcelo Alves Pinto
Producing specific antibodies in chickens is an attractive approach for diagnosis or therapeutic applications. Besides the high immunoglobulin Y (IgY) yield transferred to the egg yolk and its suitability for large-scale production, such an approach is more bioethical for animal maintenance. The IgY technology offers new possibilities for application in human and veterinary diagnostics and therapeutics, including strategies for treating severe intestinal diseases in children, particularly in emerging countries. Herein, we describe the production and purification of polyclonal antibodies against rotavirus group A (RVA) in immunised hens aiming at its application in prophylaxis and treatment of rotavirus-induced diarrhoea. For this purpose, we inoculated Rhodia laying chickens (Gallus gallus domesticus) with two or three doses of RVA combined with adjuvants or only adjuvants (control group). As the egg-laying period began, the yolk protein purification processes yielded a high concentration of specific IgY, the highest titre resulting from the group of hens that received three doses of the immunogen. The purified IgY blocked the functional activity of RVA in MA-104 cells, thus confirming the neutralisation ability. Therefore, anti-RVA IgY could be a promising candidate for pre- and post-exposure prevention or treatment of rotavirus-induced diarrhoea.

15 May 2015 in Memórias do Instituto Oswaldo Cruz
Verified
Journal Article
Open access
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GBGentil Arthur Bentes
Gentil Arthur Bentes
NLNatália Maria Lanzarini
Natália Maria Lanzarini
LLLyana Rodrigues Pinto Lima
Lyana Rodrigues Pinto Lima
PMPedro Paulo de Abreu Manso
Pedro Paulo de Abreu Manso
ASAlexandre Da Silva
Alexandre Da Silva
MPMarcelo Alves Pinto
Marcelo Alves Pinto
An increasing amount of research has been conducted on immunoglobulin Y (IgY) because the use of IgY offers several advantages with respect to diagnostic testing, including its easy accessibility, low cost and translatability to large-scale production, in addition to the fact that it can be ethically produced. In a previous work, immunoglobulin was produced and purified from egg yolks (IgY) reactive to hepatitis A virus (HAV) antigens. In the present work, this anti-HAV-specific IgY was used in an indirect immunofluorescence assay to detect viral antigens in liver biopsies that were obtained from experimentally infected cynomolgus monkeys. Fields that were positive for HAV antigen were detected in liver sections using confocal microscopy. In conclusion, egg yolks from immunised hens may be a reliable source for antibody production, which can be employed for immunological studies.

4 July 2018 in Viruses
Verified
Journal Article
Open access
PDF file
GBGentil Arthur Bentes
Gentil Arthur Bentes
JGJuliana Rodrigues Guimarães
Juliana Rodrigues Guimarães
EVEduardo De Mello Volotão
Eduardo De Mello Volotão
AFAlexandre Madi Fialho
Alexandre Madi Fialho
CHCleber Hooper
Cleber Hooper
MPMarcelo Alves Pinto
Marcelo Alves Pinto
Group A rotaviruses (RVA) are one of the most common causes of severe acute gastroenteritis in infants worldwide. Rotaviruses spread from person to person, mainly by faecal–oral transmission. Almost all unvaccinated children may become infected with RVA in the first two years of life. The establishment of an experimental monkey model with RVA is important to evaluate new therapeutic approaches. In this study, we demonstrated viral shedding and viraemia in juvenile–adult Macaca fascicularis orally inoculated with Wa RVA prototype. Nine monkeys were inoculated orally: seven animals with human RVA and two control animals with saline solution. During the study, the monkeys were clinically monitored, and faeces and blood samples were tested for RVA infection. In general, the inoculated animals developed an oligosymptomatic infection pattern. The main clinical symptoms observed were diarrhoea in two monkeys for three days, associated with a reduction in plasmatic potassium content. Viral RNA was detected in seven faecal and five sera samples from inoculated animals, suggesting virus replication. Cynomolgus monkeys are susceptible hosts for human Wa RVA infection. When inoculated orally, they presented self-limited diarrhoea associated with presence of RVA infectious particles in faeces. Thus, cynomolgus monkeys may be useful as animal models to evaluate the efficacy of new antiviral approaches.