Papers by GABRIEL MARTINS
O trabalho investiga a ocorrencia do fenomeno da curva J e a validade da condicao de Marshall-Ler... more O trabalho investiga a ocorrencia do fenomeno da curva J e a validade da condicao de Marshall-Lerner para a balanca comercial do Estado do Ceara com dados mensais entre janeiro de 2000 e julho de 2013 e vetores de correcao de erros. Na maioria dos modelos considerados, a reposta das exportacoes liquidas cearenses a uma depreciacao cambial se mostra positiva e elastica, validando, portanto, a condicao de Marshall-Lerner. Essa resposta se mostrou maior para os bens industrializados. Alem disso, o impacto da atividade industrial cearense se mostrou positivo e elastico para a sua balanca comercial e a atividade externa parece nao influencia-la. Por fim, o exame das relacoes de curto prazo revelou a ocorrencia do fenomeno da curva J na maioria dos casos analisados.
con-cluded that the inventory of infecting Leptospira serogroupsrevealed that current vaccines in... more con-cluded that the inventory of infecting Leptospira serogroupsrevealed that current vaccines in France are not fully capableof preventing leptospirosis. In total, 394 cattle were diag-nosed with clinical leptospirosis, and the results suggestedinfection by serogroups Australis (43%), Sejroe (33%), andGrippotyphosa (17%).We share our experience with bovine leptospirosis in Braziland compare it with the scenario described in France.Infected cattle are commonly asymptomatic and may shedthe bacterium in urine for long periods.
Anais do IV Simpósio de Engenharia, Gestão e Inovação, 2021
Comparative Immunology, Microbiology and Infectious Diseases, 2020
The first experimental infections with Leptospira in ruminants were conducted in the 1950s, prima... more The first experimental infections with Leptospira in ruminants were conducted in the 1950s, primarily assessed the pathogenesis caused by serovar Pomona in cows. Throughout the decades, experimental infections have also demonstrated the clinical aspects of the infection by other strains, mainly Hardjo. Despite the important outcomes observed in experimental infections in ruminants, there is still a large discrepancy regarding the ideal dose, route, strain, model species or animal age that should be used to reproduce the acute and chronic leptospirosis in ruminants. In this context, the present study aimed to review the historical processes involved on the experimental leptospiral infection in ruminants. The inclusion criteria were papers that clearly described inoculation route, strain, dose, clinical signs and animal age. Overall, 37 experiments were noted. The most frequently reported clinical signs were fever, prostration, hematuria and death, with the majority of them occurring in young animals infected by incidental strains. Regarding reproductive problems, they occurred in the majority of the experiments and were also more related to incidental strains. In this context, abortions, retained placenta and weak fetuses were the most frequent symptoms. Noteworthy that although the mechanisms of the clinical acute disease either systemic or reproductive, is reasonably well understood, the physiopathology involved on reproductive problems due to the silent chronic infection is less discussed and remains to be elucidated. In this context, it is evident the need for studies focused on the genital infection and reproductive aspects of leptospiral infection in ruminants.
Nova Economia, 2020
Resumo Este artigo analisa os impactos de curto e de longo prazo das desvalorizações cambiais sob... more Resumo Este artigo analisa os impactos de curto e de longo prazo das desvalorizações cambiais sobre as exportações líquidas totais, de básicos e de industrializados para um painel de estados brasileiros a partir da aplicação de modelos Panel Vector Autoregression (PVAR), para testar a ocorrência do fenômeno da curva J, e do Panel Dynamic Ordinary Least Squares (PDOLS), para investigar a validade da condição de Marshall-Lerner. Em todos os modelos considerados a resposta das exportações líquidas dos estados brasileiros a uma depreciação cambial se mostra positiva, validando, portanto, a condição de Marshall-Lerner. Essa resposta é maior para os bens industrializados. Como previsto pela teoria, a renda doméstica apresenta impacto negativo e estatisticamente robusto sobre o saldo comercial, enquanto a renda externa apresenta repercussão positiva. Os resultados indicam a ocorrência da curva J para os totais e os industrializados.
Blucher Medical Proceedings, 2019
Acta Scientiae Veterinariae, 2019
Background: Leptospirosis is currently a source of significant economic losses in the agribusines... more Background: Leptospirosis is currently a source of significant economic losses in the agribusiness; as such, experimental studies on this infection are required to develop a better understanding of the pathogenesis, treatment, and immunoprophylaxis of the disease. Sheep may represent a good model for ruminants in such models. Despite the extent of the studies that has been conducted thus far, researchers have yet to reach a consensus on the experimental practices to apply for leptospirosis in this animal species, and several gaps in understanding remain. To bridge these gaps, the present study aimed to assess the usage of several tools for the monitoring of experimental leptospirosis in sheep.Material, Methods & Results: Twelve Santa Ines sheep of different ages were each allocated to one of four groups (A, B, C, and D). The subjects in groups A, B, and C received different doses of Leptospira interrogans serogroup Icterohemorrhagiae by intraperitoneal route, 1x102, 1x105, and 1x108...
Journal of Equine Veterinary Science, 2018
This study investigated the risk factors associated with seroreactivity to Leptospira sp. in hors... more This study investigated the risk factors associated with seroreactivity to Leptospira sp. in horses from Brazilian Amazon. Blood samples were collected and Microscopic agglutination test (MAT) was performed; and univariate and multivariate analysis was conducted for association with risk factors. General seroprevalence was 32.7% and the most prevalent serogroup observed was Sejroe (5.9%). Seroreactivity was associated with age, sex, activity (work, leisure or both), feed supplementation, trash accumulation and presence of felines. Epidemiology of leptospirosis remains poorly understood in Amazon region, particularly in livestock, requiring more studies in order to improve control and prevention measures.
O trabalho investiga a ocorrencia do fenomeno da curva J e a validade da condicao de Marshall-Ler... more O trabalho investiga a ocorrencia do fenomeno da curva J e a validade da condicao de Marshall-Lerner para a balanca comercial do Estado do Ceara com dados mensais entre janeiro de 2000 e julho de 2013 e vetores de correcao de erros. Na maioria dos modelos considerados, a reposta das exportacoes liquidas cearenses a uma depreciacao cambial se mostra positiva e elastica, validando, portanto, a condicao de Marshall-Lerner. Essa resposta se mostrou maior para os bens industrializados. Alem disso, o impacto da atividade industrial cearense se mostrou positivo e elastico para a sua balanca comercial e a atividade externa parece nao influencia-la. Por fim, o exame das relacoes de curto prazo revelou a ocorrencia do fenomeno da curva J na maioria dos casos analisados.
Microbial Pathogenesis, 2019
Leptospirosis is an important zoonotic disease and, in urban areas, rodents are considered the ma... more Leptospirosis is an important zoonotic disease and, in urban areas, rodents are considered the main reservoir of Leptospira to human hosts. It has been described that capybaras, the world largest rodent, also harbor and shed leptospires by urine. Although not virulent to their hosts, strains of rodent origin are virulent for the hamster. In this context we aim to investigate the virulence of Leptospira kirschneri strains of serogroup Icterohaemorrhagiae recovered from capybaras in Brazil in the hamster model. Five isolates of Leptospira recovered from asymptomatic capybaras were submitted to virulence tests following the suggested protocols and the 3Rs policy for experimental science. Briefly, 1ml of 1x10 8 leptospires was inoculated intraperitoneally four times in one hamster for each strain. Four days after inoculation, a blood sample was collected via the gingival route for confirmation of blood culture infection. The infected animals were kept isolated in microisolators to observe clinical signs and monitored daily till day 21 post-inoculation. None strain caused acute disease in hamsters but were able to colonize their kidneys. The present study demonstrated that although Icterohaemorrhagiae strains are often reported as virulent, not all strains of that serogroup are indeed aggressive. Concluding, we report that strains of L. kirschneri serogroup Icterohaemorrhagiae recovered from healthy capybaras presented an atypical virulence to the hamster model, what reinforces that virulence is an intrinsic strains characteristic.
Nova Economia, 2020
Resumo Este artigo analisa os impactos de curto e de longo prazo das desvalorizações cambiais sob... more Resumo Este artigo analisa os impactos de curto e de longo prazo das desvalorizações cambiais sobre as exportações líquidas totais, de básicos e de industrializados para um painel de estados brasileiros a partir da aplicação de modelos Panel Vector Autoregression (PVAR), para testar a ocorrência do fenômeno da curva J, e do Panel Dynamic Ordinary Least Squares (PDOLS), para investigar a validade da condição de Marshall-Lerner. Em todos os modelos considerados a resposta das exportações líquidas dos estados brasileiros a uma depreciação cambial se mostra positiva, validando, portanto, a condição de Marshall-Lerner. Essa resposta é maior para os bens industrializados. Como previsto pela teoria, a renda doméstica apresenta impacto negativo e estatisticamente robusto sobre o saldo comercial, enquanto a renda externa apresenta repercussão positiva. Os resultados indicam a ocorrência da curva J para os totais e os industrializados.
Acta tropica, 2018
Vaccination is one of the most important measures for the control of bovine leptospirosis. Despit... more Vaccination is one of the most important measures for the control of bovine leptospirosis. Despite the broad usage of vaccination against leptospirosis in cattle worldwide, the dynamics of the post-vaccine immune response remain controversial and many aspects are still unclear, particularly in naturally-infected animals. Thus, the objective of this study is to describe the dynamics of humoral response in naturally-infected cattle after vaccination against leptospirosis. A total of 162 cows were studied, consisting of 129 included in the experimental group (G1), and subdivided into two groups, vaccinated with two different brands of bacterins, as well as 33 in the control group (G2). Serology (MAT) was performed in all cows on D0 (vaccination), then 60 and 120 days post-vaccination. Vaccination significantly elicited the production of anti-leptospiral antibodies. Seroreactivity increased rapidly but was of short duration (up to D60). Significantly, that increase was notably higher in...
Tropical animal health and production, Jan 18, 2018
Bovine leptospirosis is an important infectious disease that causes reproductive problems and eco... more Bovine leptospirosis is an important infectious disease that causes reproductive problems and economic risks, particularly in the tropics. The present study aimed to determine the extent of Leptospira infection among bovines on a slaughterhouse from Rio de Janeiro, Brazil via serological, bacteriological, and molecular tests. Two hundred eight bovines were examined in total, and we obtained 208 blood samples for serology, 198 urine samples collected via direct bladder puncture for polymerase chain reaction (PCR) and culture, 208 kidney samples (one from each animal) for PCR and culture, and 92 vaginal fluid samples from sterile swabs for PCR and culture. Serology demonstrated that 77/208 (37%) of the animals presented anti-Leptospira antibodies. Serogroup Sejroe was by far the most common. One hundrd thirty-three animals (63.9%) were PCR positive in at least one of the tested samples and were considered as Leptospira carriers. Furthermore, ten isolates were obtained by pure culture,...
Journal of Equine Veterinary Science, 2017
Leptospirosis causes substantial economic losses in horses. Nevertheless, humoral response post-v... more Leptospirosis causes substantial economic losses in horses. Nevertheless, humoral response post-vaccine is not well described and there is a paucity of knowledge regarding the dynamics of the response in naturally infected horses under field conditions. Fifty-four randomly selected mares, 36 vaccinated (Group I), and non-vaccinated (II-control), were used. Mares in Group I were given two doses of a multivalent (12 antigens) commercial vaccine (D0 and booster on D40). Blood samples were collected (for MAT and ELISA) at D0, D7, D14, D21, D30, D60 and D90. Vaccination significantly interfered with production of anti-leptospiral antibodies. Seroreactivity increased rapidly, but was of short duration (up to D60). Responses varied among serogroups present in the vaccine, with the most intense responses against those serogroups that were previously circulating in the herd (Icterohaemorrhagiae and Australis). Therefore, we concluded that vaccines elicited a significant humoral response in horses.
Microbial Pathogenesis, 2017
International journal of biological macromolecules, Jan 6, 2017
Polymer blending is a strategy commonly used to obtain hybrid materials possessing properties bet... more Polymer blending is a strategy commonly used to obtain hybrid materials possessing properties better than those of the individual constituents regarding their use in scaffolds for Tissue Engineering. In the present work, the scaffolds produced by electrospinning solutions of polymeric blends obtained using a polyester (polycaprolactone, PCL), a polysaccharide (chitosan, CS) and a protein (gelatin extracted from cold water fish skin, GEL), were investigated. Solutions conductivity, shear viscosity and surface tension were determined. GEL-containing scaffolds were crosslinked with vapour phase glutaraldehyde (GTA). The scaffolds were characterized physico-chemically regarding fibre morphology, porosity, water contact angle, mechanical properties, chemical bonds and fibre and dimensional stability upon immersion in water and cell culture medium. The scaffolds were further tested in vitro for cell adhesion, growth and morphology of human foetal fibroblasts (cell line HFFF2). Results sho...
Ultrastructural pathology
1. Leapman RD, Rizzo NW. Towards single atom analysis of biological structures. Ultramicroscopy 1... more 1. Leapman RD, Rizzo NW. Towards single atom analysis of biological structures. Ultramicroscopy 1999;78:251. 2. Ingram P, Shelburne JD, Roggli VL, LeFurgey A. Biomedical Applications of Microprobe Analysis. Academic Press: San Diego, CA, 1999. 3. Denk W, Horstmann H. Serial block-face scanning electron microscopy to reconstruct three dimensional tissue nanostructure.PLoS Biol 2004;2(11):e329. 4. Chen S, Deng J, Yuan Y, et al. The Bionanoprobe: hard x-ray fluorescence nanoprobe with cryogenic capabilities. J Synchrotron Radiat. 2014;21(1):66.
The Canadian veterinary journal. La revue vétérinaire canadienne, 2010
This study determined the diversity of species and antimicrobial resistance of staphylococci isol... more This study determined the diversity of species and antimicrobial resistance of staphylococci isolated from dogs with a presumptive diagnosis of urinary tract infection (UTI). Urine samples from 348 dogs with clinical signs of UTI, according to clinical examination and urinalysis, were processed for isolation of Staphylococcus. Colonies in pure culture were identified by biochemical reactions and tested for susceptibility to 15 antimicrobials. Seventy isolates of staphylococci were obtained (20.1%). Staphylococcus pseudintermedius was the most frequent species (32.8%), followed by S. epidermidis (18.6%), S. simulans (15.7%), S. schleiferi schleiferi (11.4%), S. aureus (11.4%), S. schleiferi coagulans (7.2%) and S. saprophyticus (2.9%). All the isolates were resistant to at least 1 drug and 77.1% were multiresistant. The study reports the alarming antimicrobial resistance of members of the Staphylococcus genus isolated from canine UTI and highlights the importance of coagulase-negativ...
Ciência Rural, 2010
The objective was to study haematological and biochemical alterations associated to seropositivit... more The objective was to study haematological and biochemical alterations associated to seropositivity to Leptospira interrogans serovar Bratislava infection in horses with reproductive alterations, such as neonatal deaths, embryonic deaths and abortions. A flock of mares with poor reproductive performance was studied. Eighty-two (58.6%) were seropositive (titre 200); 72 of those (87.8%) for Bratislava. Slight haematological and biochemical alterations were observed, being more frequent (P<0.05) in horses seropositive versus seronegative. In conclusion horses seropositive for Bratislava had no consistent, severe alteration in values for hematology and biochemistry serum. Those findings reinforce this serovar as adapted to the horse and causing only mild symptoms, focused on reproductive problems.
Developmental cell, Jan 11, 2014
The stereotypic left-right (LR) asymmetric distribution of internal organs is due to an asymmetri... more The stereotypic left-right (LR) asymmetric distribution of internal organs is due to an asymmetric molecular cascade in the lateral plate mesoderm (LPM) that is originated at the embryonic node. In chicken embryos, molecular asymmetries at Hensen's node are created by leftward cell movements that occur transiently. What terminates these movements, and, moreover, what is the impact of prolonging them on the LR asymmetry cascade? We show that leftward movements last longer when N-cadherin function is blocked and cease prematurely when N-cadherin is overexpressed on the right side of the node. The prolonged leftward movements lead to loss of asymmetric expression of fgf8 and nodal at the node region. This originates an abnormal expression of the asymmetric genes cer1 and snai1 in the LPM, resulting in mispositioned hearts. We conclude that N-cadherin stops the leftward cell movements and that this termination is an essential step in the establishment of LR asymmetry.
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Papers by GABRIEL MARTINS