Characterization and in vivo toxicological evaluation of multi-walled carbon nanotubes: a low-dose repeated intratracheal administration study.

This study characterized and investigated the toxicity of two multi-walled carbon nanotubes (MWCNT) NM-401 and NM-403 at 60 and 180 µg after four repeated intratracheal instillations; follow-up times were 3, 7, 30, and 90 days after the last instillation. NM-401 was needle-like, long, and thick, while NM-403 was entangled, short, and thin. Both MWCNT types induced transient pulmonary and systemic alterations in renal function and oxidative lipid damage markers in recent times. Animals showed general toxicity in the immediate times after exposures, in addition to increased pulmonary LDH release at day 3. In further times, decreased liver and kidney relative weights were noted at higher MWCNT doses. Lung histological damages included pulmonary fibrosis, for both MWCNT types, similarly to asbestos; single liver and kidney histological alterations were present. Repeated instillations led to persistent pulmonary damage at low doses, and possibly the extrapulmonary effects may be associated with the consecutive exposures.

Monoclonal antibodies against LipL32 confer prophylactic protection against lethal leptospirosis challenge in animal model.

Leptospirosis is a widespread zoonotic disease caused by pathogenic spirochetes of the genus Leptospira. The commercially available vaccines are bacterins that offer limited protection, short-term effect, and serovar-specific immunity. The development of novel immunization strategies is crucial to control the infection and decrease the chances of new outbreaks. In this study, purified monoclonal antibodies (mAbs) anti-LipL32 (1D9 and mAb3) were evaluated by their capacity to bind and neutralize the pathogen improving host survival. For that, an in vitro growth inhibition assay, and in vivo passive immunization were performed in animal model. Syrian hamsters were passively immunized by three different strategies. Hamsters immunized with mAb3 6 h prior to the lethal challenge showed a significantly higher survival rate of 61.1%, and a significant reduction in tissue damage in the lungs. Cumulatively, our results showed that anti-LipL32 mAbs inhibited the growth of L. interrogans in vitro, and that passive immunization offered significant protection in animal model when administered prior to infection.

Evaluation of different strategies to promote a protective immune response against leptospirosis using a recombinant LigA and LigB chimera.

Leptospirosis is a zoonosis of worldwide distribution, caused by infection with pathogenic Leptospira species. The vaccines that are currently available are bacterins, with limited human use, that confer short-term, serovar-specific immunity. Lig proteins are considered to be the best vaccine candidates to date. Here, we aimed to construct a recombinant Lig chimera (LC) comprised of LigAni and LigBrep fragments, and to evaluate it as subunit or DNA vaccine using different administration strategies. Vaccines were formulated with 50 µg of recombinant LC associated with different adjuvants or with 100 µg of pTARGET/LC. Four-week-old hamsters received two doses of vaccine with different strategies and were challenged with 5 × DL50Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130. The immune response generated by Lig chimera conferred 100% protection to hamsters treated with at least one dose of recombinant LC. Despite the high levels of antibodies that vaccinated animals produced, a sterilizing immunity was not achieved. The lack of a sterilizing immunity could indicate the importance of a mixed humoral and cellular immune response. The present study generated insights that will be useful in the future development of improved subunit vaccines against leptospirosis.

Recombinant BCG strains expressing chimeric proteins derived from Leptospira protect hamsters against leptospirosis.

Leptospirosis is a zoonosis that is responsible for one million human cases per year. Fusing multiple immunogenic antigens represents a promising approach to delivering an effective vaccine against leptospirosis. Mycobacterium bovis bacillus Calmette-Guérin (BCG) is a potential vaccine vector due to its adjuvant properties and safety. Two chimeric genes based on genic sequences of ligANI, ligBrep, lipL32, and lemA, were individually cloned into five BioBrick vectors with different promoters (pAN, Hsp60, 18 kDa, Ag85B and Ag85B plus signal sequence) for antigen expression in BCG. Groups of ten hamsters were vaccinated with recombinant BCG (rBCG) strains in two doses of 106 CFU and challenged with 5 × LD50 of L. interrogans serovar Copenhageni. All rBCG vaccines expressing chimera 1, based on antigens LipL32, LigANI, and LemA, under the control of any promoter, protected 80-100% of the hamsters from challenge (P < 0.05) and four of them also protected from renal carrier status; for chimera 2, based on LigANI and LigBrep antigens, the only vaccine that afforded survival rates statistically different from the control was the vaccine that incorporated the pAN promoter (60% of survival). A single vaccine dose was sufficient to induce significant IgG levels by all vaccine compositions evaluated; however, humoral response was not related to protection. These findings suggest that the combination of potential vaccine candidates in chimeric antigens and the use of BCG as a live vector are promising strategies by which it is possible to obtain an effective and sterilizing vaccine against leptospirosis.

Infection with Leptospira kirschneri Serovar Mozdok: First Report from the Southern Hemisphere.

Leptospirosis is a global zoonosis caused by pathogenic Leptospira spp. In this study, we characterized two Leptospira kirschneri serogroup Pomona serovar Mozdok isolates, one obtained from a dog and the other from a patient with severe leptospirosis, 4 years later. Histopathological analysis showed that both isolates caused severe tissue damage when used to infect hamsters. While L. kirschneri serogroup Pomona serovar Mozdok is endemic in animals in Europe, there is only one report of human leptospirosis in the literature. Although strains belonging to L. kirschneri serogroup Pomona have been identified in cases of human leptospirosis in Europe, serovar Mozdok has not yet been implicated. The 4-year interval between isolations and the fact that this is the first report of serovar Mozdok as the causative agent of human leptospirosis in the southern hemisphere, demonstrates its epidemiological importance to public health. Moreover, the presence of serovar Mozdok in Brazil has the potential to affect vaccine and diagnostic test development.

Immunological and molecular characterization of Leptospira interrogans isolated from a bovine foetus.

Cattle are commonly infected with pathogenic leptospires, and similarly to rodents, they excrete the bacteria in their urine and can transmit the pathogen from animal to animal or animal to human. Thus, surveillance and monitoring systems for detection of new Leptospira serovars are important for the control of leptospirosis. Here, we report the isolation of a spirochete from a stillborn bovine foetus and its characterization by immunological and molecular techniques. A variable number tandem repeat profile using seven discriminatory primers identified the spirochete as belonging to species Leptospira interrogans serogroup Australis serovar Muenchen. A phenotypic analysis using monoclonal antibodies (mAbs) against leptospiral membrane-associated proteins confirmed the expression of important virulence and pathogenicity factors (LipL32 and LigBrep). Out of 120 reference sera tested, 22 positive (36.66%) and 9 negative (15%) also reacted with the new isolate. Furthermore, the serovar Muenchen isolate was virulent in hamster model. The animal inoculated developed acute lethal infection characterized by hepatic, pulmonary and renal lesions. Local isolates exhibited unique characteristics that differed from those of reference strains; therefore, isolation of leptospires is useful in the surveillance of local pathogenic serovars. In conclusion, the data obtained from this study can contribute to the epidemiological understanding and control of leptospirosis in southern Brazil.

Efeitos do treinamento moderado contínuo sobre parâmetros imunológico e metabólico de ratos suplementados com maltodextrina / Effects of continuous moderate training on immune and metabolic parameters of rats supplemented with maltodextrin

O objetivo deste estudo foi verificar os efeitos do exercício moderado contínuo sobre a contagem total e diferencial de leucócitos, as concentrações de glicose sérica e os teores lipídicos de ratos suplementados e não suplementados com solução carboidratada. Para tanto, 35 ratos Wistar, machos foram distribuídos em quatro grupos: sedentários não suplementado (n = 10) e suplementado (n = 8); treinados em exercício aeróbio moderado contínuo não suplementado (n = 9) e suplementado (n = 8). O período de treinamento foi de seis semanas de natação em padrão contínuo com sobrecarga correspondente a 3% do peso corporal. Durante cinco dias os animais foram suplementados com uma dose diária de 0,48 g.kg-1 de maltodextrina dissolvida em água ou receberam água pura. O exercício moderado causou uma diminuição significativa na glicemia (p < 0,001) e no número de linfócitos sanguíneos (p < 0,01), entretanto, a maltodextrina proporcionou um aumento significativo nos linfócitos dos animais treinados (p < 0,03). Não houve efeito do treinamento e da maltodextrina no perfil lipídico. Conclui-se que com seis semanas de treinamento foi possível causar queda no número de linfócitos e concentração de glicose sérica, mas com cinco dias de suplementação o declínio na contagem de linfócitos foi atenuado sem, no entanto, causar elevações no perfil lipídico.

The objective of this study was to determine the effects of continuous moderate exercise on the differential and total count leukocyte, serum glucose concentration and lipid levels of rats supplemented and not supplemented with carbohydrate solution. To this purpose, thirty-five male Wistar rats were divided into four groups: sedentary non-supplemented (n = 10) and supplemented (n = 8), trained in continuous moderate aerobic exercise non-supplemented (n = 9) and supplemented (n = 8). The training of continuous swimming was developed during six week with 3% body weight overload. For five days the animals were supplemented with 0.48 g.kg-1 maltodextrin daily dose dissolved in water or pure water. Moderate exercise caused a significant decrease in blood glucose (p < 0.001) and in the number of blood lymphocytes (p < 0.01). Additionally, the maltodextrin significantly increased the number of lymphocytes of trained animals (p < 0.03). There was no effect of training and maltodextrin on the lipid profile. The results allowed to conclude that with six weeks of training it was possible to cause a drop in the number of lymphocytes and in the concentration of serum glucose, but with five days of supplementation the decline in the lymphocyte count was attenuated without, however, cause elevations in the lipid profile.

Hemangioma cavernoso da vesícula biliar: causa de hemorragia digestiva alta? / Cavernous hemangioma of the gallblader: cause of upper gastrointestinal bleeding?

Os autores descrevem o achado de um raro caso de neoplasia benigna da vesícula biliar, qual seja, o de um hemangioma à cavernoso mural. Essa neoplasia foi encontrada num paciente masculino, com sangramentos digstivos de repetiçåo, com estudo endoscópio digestivo alto normal, dois meses após o último sangramento, constituindo-se num achado ocasional de colecistectomia indicada por quadro agudo