Dengue infection in mice inoculated by the intracerebral route: neuropathological effects and identification of target cells for virus replication.

Dengue is an important arboviral infection, causing a broad range symptom that varies from life-threatening mild illness to severe clinical manifestations. Recent studies reported the impairment of the central nervous system (CNS) after dengue infection, a characteristic previously considered as atypical and underreported. However, little is known about the neuropathology associated to dengue. Since animal models are important tools for helping to understand the dengue pathogenesis, including neurological damages, the aim of this work was to investigate the effects of intracerebral inoculation of a neuroadapted dengue serotype 2 virus (DENV2) in immunocompetent BALB/c mice, mimicking some aspects of the viral encephalitis. Mice presented neurological morbidity after the 7th day post infection. At the same time, histopathological analysis revealed that DENV2 led to damages in the CNS, such as hemorrhage, reactive gliosis, hyperplastic and hypertrophied microglia, astrocyte proliferation, Purkinje neurons retraction and cellular infiltration around vessels in the pia mater and in neuropil. Viral tropism and replication were detected in resident cells of the brain and cerebellum, such as neurons, astrocyte, microglia and oligodendrocytes. Results suggest that this classical mice model might be useful for analyzing the neurotropic effect of DENV with similarities to what occurs in human.

Peripheral effects induced in BALB/c mice infected with DENV by the intracerebral route.

The lack of an immunocompetent animal model for dengue mimicking the disease in humans is a limitation for advances in this field. Inoculation by intracerebral route of neuroadapted dengue strains in mice is normally lethal and provides a straightforward readout parameter for vaccine testing. However, systemic effects of infection and the immune response elicited in this model remain poorly described. In the present work, BALB/c mice infected by the intracerebral route with neuroadapted DENV2 exhibited several evidences of systemic involvement. DENV-inoculated mice presented virus infective particles in the brain followed by viremia, especially in late stages of infection. Infection induced cellular and humoral responses, with presence of activated T cells in spleen and blood, lymphocyte infiltration and tissue damages in brain and liver, and an increase in serum levels of some pro-inflammatory cytokines. Data highlighted an interplay between the central nervous system commitment and peripheral effects under this experimental condition.

Utilização do filme de quitosana na reparação de tendão em coelhos / Use of the film of chitosan in the repair of tendons in rabbits

Com este trabalho objetivou-se avaliar o processo de cicatrização do tendão em coelhos, utilizando-se no grupo tratamento o filme de quitosana, por meio de uma análise clínico-cirúrgica e histológica. Foram utilizados 12 coelhos adultos, separados em grupo controle (GC) e grupo tratamento (GT), nos quais se realizou uma secção parcial do tendão gastrocnêmio de ambos os membros pélvicos. A avaliação clínica baseou-se na presença de reação inflamatória, infecção, dor e deiscência da sutura. Para a avaliação histológica, foi realizado um estudo comparativo do processo cicatricial por meio do tipo de células, da quantidade de tecido conjuntivo e da organização das fibras colágenas entre os grupos e os momentos. Nas feridas cirúrgicas, não foram observadas secreção, dor ou deiscência. Na histologia comparativa entre os grupos, o GC apresentou melhor processo cicatricial em relação ao GT, aos 60 dias. Aos 90 dias, no GT a cicatrização já esboça recuperação do tendão, com reorganização da celularidade e das fibras colágenas no tecido conjuntivo denso modelado. Concluiu-se que a quitosana estimula rápido crescimento celular, mas de forma desorganizada, e que a cicatrização completa só ocorre após 90 dias da sua implantação no tecido...

This work aimed to evaluate the process of tendon healing in rabbits, using the treatment group in chitosan film through a clinical, surgical and histological analysis. In the experiment, 12 adult rabbits were used, divided into control group (CG) and treatment group (TG), which were held in the partial section of the gastrocnemius tendon of both limbs. Clinical assessment was based on the presence of inflammation, infection, pain and suture dehiscence. For histological evaluation a comparative study of the healing process through the cell type, amount of connective tissue and collagen fiber organization was performed between groups and times. In surgical wounds no secretion, pain or dehiscence were observed. In the comparative histology between groups, the CG showed better healing compared to TG, at 60 days. On day 90 the TG already outlines tendon recovery with reorganization of cellularity and collagen fibers in the dense connective tissue modeled. It was concluded that chitosan stimulates faster cell growth, but it is haphazardly, and that complete healing occurs after 90 days of their implantation in tissue...

Use of chitosan and ß-tricalcium phosphate, alone and in combination, for bone healing in rabbits.

The aim of this research was to evaluate the process of bone regeneration in rabbits, using chitosan and beta-tricalcium phosphate (ß-TCP) independently and in combination. A total of 12 New Zealand rabbits of both sexes, with average weight of 3.0 ± 0.57 kg were used. Animals were randomly divided into two experimental time points, with six animals euthanized 45 days after surgery and six euthanized 90 days after surgery. We performed two osteotomies in each tibia. The left tibia was used for the chitosan (QUI) and control groups, and the right tibia was used for the ß-TCP alone and in combination with chitosan (QUI+TCP) groups. Tomographic evaluation showed no statistically significant difference among groups; however radiopacity was higher in the treated groups. Comparative descriptive histological evaluation found that treatment groups stimulated a more pronounced tissue repair reaction and accelerated bone repair. Morphometric analysis showed that treatment groups presented statistically higher bone formation compared with the control group.

Fratura de patela com ruptura do tendão patelar em um cão: relato de caso / Patella fracture with rupture of the patellar tendon in a dog: case report

Relatou-se a ocorrência de fratura patelar associada à ruptura do tendão patelar em um cão sem raça definida, macho, atendido em um hospital veterinário escola. A técnica utilizada foi a combinação de fixação óssea com fio de Kirschner e aplicação de banda de tensão, recomendada em fraturas transversais da patela. Para reparar a lesão do tendão patelar, realizou-se a sutura tipo Kessler modificada com fio de náilon 0,80mm. No retorno do paciente, 150 dias após o procedimento cirúrgico, havia processo cicatricial ósseo avançado da patela. Concluiu-se que as medidas adotadas para reparação da lesão foram eficazes.

It is reported the occurrence of patellar fracture associated with rupture of the patellar tendon in a mongrel male dog referred to a Teaching Veterinary Hospital. The used technique was the combination of bone fixation with Kirschner wire and application of tension band recommended in most transverse fractures of the patella. To repair the damage to the patellar tendon, the modified Kessler suture with nylon 0.80mm was performed. When the patient returned 150 days after surgery, advanced bone healing process was observed in patella. It was concluded that the measures taken to repair the injury were effective.

Ocorrência de Hepatozoon spp. (Apicomplexa, Hepatozoidae) em serpentes captive Boa constrictor mantidas em cativeiro no semiárido do estado do Rio Grande do Norte / Occurrence of Hepatozoon spp. (Apicomplexa, Hepatozoidae) in captive Boa constrictor snakes in the semi-arid of Rio Grande do Norte State, Northeastern Brazil

The occurrence of Hepatozoon spp. in the blood cells of captive Boa constritor in captivity in the semi-arid of the Rio Grande do Norte State, Brazil, was analyzed. Blood samples from Geochelone carbonaria (n = 6), Geochelone denticulata (n = 4), Boa Constrictor (n = 7), and Tupinanbis teguixim (n = 10) were used. All snakes presented Hepatozoon spp. in their blood cells, and few erythrocytes were infected. G. carbonaria, G. denticulate, and T. teguixim were negative for Hepatozoon spp. gametocytes research. This is the first report of the occurrence of Hepatozoon spp. in captive B. constritor in the studied area.

DNA vaccines against dengue virus based on the ns1 gene: the influence of different signal sequences on the protein expression and its correlation to the immune response elicited in mice.

We analyzed four DNA vaccines based on DENV-2 NS1: pcENS1, encoding the C-terminal from E protein plus the NS1 region; pcENS1ANC, similar to pcENS1 plus the N-terminal sequence from NS2a (ANC); pcTPANS1, coding the t-PA signal sequence fused to NS1; and pcTPANS1ANC, similar to pcTPANS1 plus the ANC sequence. The NS1 was detected in lysates and culture supernatants from pcTPANS1-, pcENS1- and pcENS1ANC-transfected cells and not in cells with pcTPANS1ANC. Only the pcENS1ANC leads the expression of NS1 in plasma membrane, confirming the importance of ANC sequence for targeting NS1 to cell surface. High levels of antibodies recognizing conformational epitopes of NS1 were induced in mice immunized with pcTPANS1 and pcENS1, while only few pcENS1ANC-inoculated animals presented detectable anti-NS1 IgG. Protection against DENV-2 was verified in pcTPANS1- and pcENS1-immunized mice, although the plasmid pcTPANS1 induced slight higher protective immunity. These plasmids seem to activate distinct patterns of the immune system.