Early and late neuropathological features of meningoencephalitis associated with Maraba virus infection.

Maraba virus is a member of the genus Vesiculovirus of the Rhabdoviridae family that was isolated in 1983 from sandflies captured in the municipality of Maraba, state of Pará, Amazônia, Brazil. Despite 30 years having passed since its isolation, little is known about the neuropathology induced by the Maraba virus. Accordingly, in this study the histopathological features, inflammatory glial changes, cytokine concentrations, and nitric oxide activity in the encephalon of adult mice subjected to Maraba virus nostril infection were evaluated. The results showed that 6 days after intranasal inoculation, severe neuropathological-associated disease signs appeared, including edema, necrosis and pyknosis of neurons, generalized congestion of encephalic vessels, and intra- and perivascular meningeal lymphocytic infiltrates in several brain regions. Immunolabeling of viral antigens was observed in almost all central nervous system (CNS) areas and this was associated with intense microglial activation and astrogliosis. Compared to control animals, infected mice showed significant increases in interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (INF)-γ, MCP-1, nitric oxide, and encephalic cytokine levels. We suggest that an exacerbated inflammatory response in several regions of the CNS of adult BALB/c mice might be responsible for their deaths.

Early and late neuropathological features of meningoencephalitis associated with Maraba virus infection

Maraba virus is a member of the genus Vesiculovirus of the Rhabdoviridae family that was isolated in 1983 from sandflies captured in the municipality of Maraba, state of Pará, Amazônia, Brazil. Despite 30 years having passed since its isolation, little is known about the neuropathology induced by the Maraba virus. Accordingly, in this study the histopathological features, inflammatory glial changes, cytokine concentrations, and nitric oxide activity in the encephalon of adult mice subjected to Maraba virus nostril infection were evaluated. The results showed that 6 days after intranasal inoculation, severe neuropathological-associated disease signs appeared, including edema, necrosis and pyknosis of neurons, generalized congestion of encephalic vessels, and intra- and perivascular meningeal lymphocytic infiltrates in several brain regions. Immunolabeling of viral antigens was observed in almost all central nervous system (CNS) areas and this was associated with intense microglial activation and astrogliosis. Compared to control animals, infected mice showed significant increases in interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (INF)-γ, MCP-1, nitric oxide, and encephalic cytokine levels. We suggest that an exacerbated inflammatory response in several regions of the CNS of adult BALB/c mice might be responsible for their deaths.

Brucella canis infection in dogs from commercial breeding kennels in Brazil.

Canine brucellosis caused by Brucella canis is a neglected zoonosis worldwide and is a leading cause of reproductive failure in dogs, often causing substantial economic losses in breeding kennels. This study aimed to investigate the occurrence of B. canis infection in dogs of commercial breeding kennels located in São Paulo State, Brazil. A total of 753 dogs (183 males and 570 females) from 38 commercial kennels were clinically examined, and blood samples were collected for brucellosis diagnosis through blood culture. The association between clinical manifestations suggestive of brucellosis and positive results through blood culture was determined. Of the 753 dogs tested, 166 (22.0%) had at least one clinical sign suggestive of brucellosis and 158 (20.9%) had positive blood cultures. Seventy-two dogs had positive blood culture and had at least one clinical sign suggestive of brucellosis, while 91 dogs showed at least one clinical manifestation suggestive of brucellosis although blood culture was negative. Of the 38 kennels, 16 (42.1%) had at least one positive dog. The prevalence of infection in each kennel varied from 3.8% to 62.6%. Abortion/stillbirth, failure to conceive and enlargement of lymph nodes were significantly associated with brucellosis in female. No association of clinical signs and positive results in blood culture was observed in males. None of the kennels has been carrying out programmes to control brucellosis, and the sale of infected dogs was considered a common practice yielding risks to the public health, in view of the zoonotic potential of the infection.

Evaluation of an Immunochromatographic Test to the Diagnosis of Canine Brucellosis Caused by Brucella canis.

This study evaluated the performance of an immunochromatographic test (ICT) for the diagnosis of canine brucellosis caused by Brucella canis, comparing its results with that of the rapid slide agglutination test with and without the use of 2-mercaptoethanol and the agar gel immunodiffusion test (AGID). The microbiological culture, PCR and clinical examination were used as reference. According to the results obtained in clinical examination, blood culture, culture of semen and vaginal swab and PCR in blood, semen and vaginal swab, a total of 102 dogs were divided into three groups: B. canis-infected dogs (Group 1), B. canis-non-infected dogs (Group 2) and dogs with suspected brucellosis (Group 3). The diagnostic sensitivity of RSAT, 2ME-RSAT, AGID and ICT in Group 1 was, respectively, 75%, 37.5%, 27.8% and 89.58%. The diagnostic specificity of RSAT, 2ME-RSAT, AGID and ICT in Group 2 was, respectively, 91%, 100%, 100%, and 100%. In dogs with suspected brucellosis, 9.67% were RSAT positive, none was positive by 2ME-RSAT, 3.22% were AGID positive and 6.45% were ICT positive. The main drawback concerning canine brucellosis diagnosis is the lack of a highly sensitive serological assay to be used as a screening test to the rapid identification of infected animals. The ICT showed a high diagnostic specificity and a diagnostic sensitivity value greater than that observed in the RSAT, 2ME-RSAT and AGID. However, 10.41% of infected dogs had negative results by ICT. These dogs were positive by microbiological culture and/or PCR, indicating active infection and consequently a higher potential of spreading Brucella. Although rapid and simple to perform, the ICT lacked sensitivity to be used as a screening test.

Vitamin E-analog Trolox prevents endoplasmic reticulum stress in frozen-thawed ovarian tissue of capuchin monkey (Sapajus apella).

Ovarian fragments were exposed to 0.5 M sucrose and 1 M ethylene glycol (freezing solution; FS) with or without selenium or Trolox. Histological and ultrastructural analyses showed that the percentages of normal follicles in control tissue and in tissue after exposure to FS + 50 µM Trolox were similar. Trolox prevented endoplasmic reticulum (ER)-related vacuolization, which is commonly observed in oocytes and stromal tissue after exposure to FS. From the evaluated stress markers, superoxide dismutase 1 (SOD1) was up-regulated in ovarian tissue exposed to FS + 10 ng/ml selenium. Ovarian fragments were subsequently frozen-thawed in the presence of FS with or without 50 µM Trolox, followed by in vitro culture (IVC). Antioxidant capacity in ovarian fragments decreased after freeze-thawing in Trolox-free FS compared with FS + 50 µM Trolox. Although freezing itself minimized the percentage of viable follicles in each solution, Trolox supplementation resulted in higher rates of viable follicles (67 %), even after IVC (61 %). Furthermore, stress markers SOD1 and ERp29 were up-regulated in ovarian tissue frozen-thawed in Trolox-free medium. Relative mRNA expression of growth factors markers was evaluated after freeze-thawing followed by IVC. BMP4, BMP5, CTGF, GDF9 and KL were down-regulated independently of the presence of Trolox in FS but down-regulation was less pronounced in the presence of Trolox. Thus, medium supplementation with 50 µM Trolox prevents ER stress and, consequently, protects ovarian tissue from ER-derived cytoplasmic vacuolization. ERp29 but not ERp60, appears to be a key marker linking stress caused by freezing-thawing and cell vacuolization.

Characterization of two new rhabdoviruses isolated from midges (Culicoides SPP) in the Brazilian Amazon: proposed members of a new genus, Bracorhabdovirus.

Itacaiunas and Curionopolis viruses were isolated from Culicoides midges in Parauapebas municipality, Pará state, Brazil, in 1984 and 1985, respectively. Itacaiunas virus infected newborn mice and mosquito cells (C6/36), but did not replicate in some mammalian cell lineages; while Curionopolis virus infected only mice. Neither virus showed a serological relationship with any of the 195 known arboviruses circulating in Brazil, nor against 38 other rhabdoviruses isolated worldwide. Both virus particles are bullet-shaped and similar in morphology to that observed for other members of the family Rhabdoviridae. Partial nucleotide sequencing of the N protein showed that those two viruses constitute a separate clade in the family Rhabdoviridae, which we propose to be a new genus, designated Bracorhabdovirus.

Neurotropism and neuropathological effects of selected rhabdoviruses on intranasally-infected newborn mice.

Viral neurotropism is the ability of viruses to infect neuronal cells. This is well studied for herpesviruses, rabies-related viruses, and a few others, but it is poorly investigated among almost all arboviruses. In this study, we describe both the neurotropism and the neuropathological effects of Amazonian rhabdoviruses on the brains of experimentally infected-newborn mice. Suckling mice were intranasally infected with 10(-4) to 10(-8) LD50 of viruses. Animals were anaesthetized and perfused after they had become sick. Immunohistochemistry using specific anti-virus and anti-active caspase three antibodies was performed. All infected animals developed fatal encephalitis. Survival time ranged from 18 h to 15 days. Viruses presented distinct species-dependent neurotropism for CNS regions. Histopathological analysis revealed variable degrees of necrosis and apoptosis in different brain regions. These results showed that viruses belonging to the Rhabdoviridae family possess distinct tropism for CNS structures and induce different pattern of cell death depending on the CNS region.

Some observations on the fine structure of trophozoites of the haemogregarine Cyrilia lignieresi (Adeleina: Haemogregarinidae) in erythrocytes of the fish Synbranchus marmoratus (Synbranchidae).

This communication describes the fine structure of trophozoites of the haemogregarine Cyrilia lignieresi (Laveran, 1906) found in erythrocytes of the fresh-water fish Synbranchus marmoratus from Belém, Pará, North Brazil. The parasite possesses the usual structures, such as conoid, rhoptries and micronemes, seen in members of the phylum Apicomplexa. Three structures, however, appear to be characteristic features of this parasite. The parasitophorous vacuole is unusual in containing a large number of spherical bodies. Secondly, some of the dense bodies, which are usually spherical organelles, may appear as elongated structures. Thirdly, peculiar invaginations of the inner membrane appear to divide the parasite into compartments.

The fine structure of the axostyle and its associations with organelles in Trichomonads.

The fine structure of the axostyle in the protists Tritrichomonas foetus and Monocercomonas sp is described using transmission electron microscopy after quick-freezing techniques and immunocytochemistry. The axostyle microtubules presents a lateral projection formed by two protofilaments in addition to the 13 protofilaments normally found in microtubules. The axostyle is associated with other cell structures such as hydrogenosomes, endoplasmic reticulum, sigmoid filaments and glycogen particles. The microtubules of the pelta-axostylar system are connected to each other by bridges regularly spaced with an interval of 9 nm. Labeling of the axostyle was observed after cell incubation with monoclonal antibodies recognizing alpha-tubulin and acetylated-tubulin.

The fine structure of Garnia gonadati and its association with the host cell.

Most of the studies on the fine structure of protozoa of the Apicomplexa group have been carried out with members of the ToxoPlasma, Eimeria, and Plasmodium genera. In the present study we analyzed the fine structure of Garnia gonadoti parasitizing the red blood cells of the Amazonian reptile Gonatodes humeralis (Reptilia; Lacertilia). Transmission electron microscopy of thin sections showed that G. gonadoti presented all structures characteristic of the group, including the apicoplast. However, four special features were observed: (1) absence of the hemozoin (malarial) pigment; (2) a group of microtubules associated with the mitochondrion; (3) a vacuole containing electron-dense material, which resembled the acidocalcisome described in trypanosomatids; and (4) a special array of the host-cell endoplasmic reticulum around the parasitophorous vacuole.

Trophozoites of Giardia lamblia may have a Golgi-like structure.

Trophozoites of the primitive protozoan Giardia lamblia have been considered as cells which do not present the Golgi complex. Using C(6)-NBD ceramide, which has been shown to label the Golgi complex of mammalian cells, labelling of the perinuclear region of G. lamblia was observed by confocal laser scanning microscopy. Transmission electron microscopy of thin sections and of replicas of freeze-fractured cells revealed the presence of concentric perinuclear membranes resembling the Golgi complex.

Presence of a protrusion on the ventral disk of adhered trophozoites of Giardia lamblia.

About 30% of the trophozoites of Giardia lamblia, fixed while adherent to the substrate using fixative solutions designed to better preserve cytoskeletal elements, showed the presence of a ventral disk. This structure varied in shape and size and could be seen by scanning and transmission electron microscopy, as well as by confocal laser scanning microscopy of cells incubated with 3-3'-dihexyloxacarbocyanine iodide, which labels cisternae of the endoplasmic reticulum. It could also be observed in living adherent cells. A row of microtubules, a large number of glycogen particles, peripheral vesicles and concentric membranes were seen within the protrusion.

Cellular uptake and retention measurements of alkylphosphocholines in the SK-BR-3 breast cancer and Molt-4 leukemia cell line using capillary gas chromatography.

The determination of cellular content of octadecylphosphocholine (D-19391) and hexadecylphosphocholine (HePC, D-18506), two anticancer agents of the alkylphosphocholine group, using capillary gas chromatography is described. The compounds' cytotoxicity was first determined by the MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium] assay, being indicative for the concentration used in the uptake and retention measurements. D-19391 was added to the SK-BR-3 breast cancer cell line and HePC to the Molt-4 leukemia cell line in concentrations of, respectively, 18.6 and 15.0 microM, during a 36-h incubation period at 37 degrees C, 5% CO2. HePC uptake in the leukemia cells was followed by a 24-h reversibility test in drug-free medium. Subsequently, sample clean-up was performed on a weak cation-exchange column. For the quantitative analysis, HePC was used as internal standard for the D-19391 measurements and vice versa. Derivatization of the samples with trimethylsilylbromide was followed by capillary gas chromatographic analysis. From these data we conclude that our uptake results are quite similar with those of a previous study of HePC cellular uptake in the more resistant Caco-2T colon cancer cell line. Without having investigated the mechanism that underlies the cellular uptake results obtained, our study points to no direct correlation between the compounds' cellular uptake and their cytotoxic effects.

Sulfated polysaccharides from the egg jelly layer are species-specific inducers of acrosomal reaction in sperms of sea urchins.

We have characterized the fine structure of sulfated polysaccharides from the egg jelly layer of three species of sea urchins and tested the ability of these purified polysaccharides to induce the acrosome reaction in spermatozoa. The sea urchin Echinometra lucunter contains a homopolymer of 2-sulfated, 3-linked alpha-L-galactan. The species Arbacia lixula and Lytechinus variegatus contain linear sulfated alpha-L-fucans with regular tetrasaccharide repeating units. Each of these sulfated polysaccharides induces the acrosome reaction in conspecific but not in heterospecific spermatozoa. These results demonstrate that species specificity of fertilization in sea urchins depends in part on the fine structure of egg jelly sulfated polysaccharide.

Cisto parameatal: apresentacao de um caso. / Parameatalcyst: report of a case

Os autores apresentam um caso de cisto parameatal; e escassa a descricao de casos semelhantes na literatura. E feito uma revisao sobre sua etiologia e tratamento