Pathology and tissue distribution of turkey coronavirus in experimentally infected chicks and turkey poults.

Twenty 1-day-old specific pathogen free chicks and 20 1-day-old commercially derived turkey poults were inoculated with a Brazilian strain of turkey coronavirus (TCoV) to study the pathogenicity and virus distribution up to 14 days post-inoculation by histopathology, immunohistochemistry, reverse transcriptase polymerase chain reaction and sequencing. At 2-14 dpi, TCoV antigens were detected in the paranasal sinus and lachrymal accessory gland (Harderian gland) of infected chicks and in the ileum, ileocaecal junction and caecum of infected poults. Lymphocytic inflammation was present in these tissues. TCoV was re-isolated from pooled tissue suspensions of nasal concha, Harderian gland and paranasal sinus from chicks, as well as from the ileum, ileocaecal junction and caecum of poults, after three consecutive passages in 28-day-old embryonated turkey eggs. Viral RNA corresponding to the spike gene region (1178-2073 genome position) was amplified from the upper respiratory tract of chickens and from the intestinal tract of poults and phylogenetic analysis confirmed the identity as TCoV. This is the first description of TCoV antigens and mRNA in upper respiratory tissues in experimentally infected chickens.

Effects of melatonin on the Harderian gland of lipopolysaccharide-treated rats: morphological observations.

Melatonin is a free radical scavenger and antioxidant. This indol is reported to efficiently scavenge both hydroxyl and peroxyl radicals and it also reduces both in vitro and in vivo tissue damage due to oxidants which generate oxygen toxic radicals. Lipopolysaccharide (LPS) administration induces oxidative damage in various tissues mainly due to its ability to increase reactive oxygen species. In the present work, we studied the morphological changes and lipid peroxidation in the Harderian gland after LPS administration and the effects of melatonin in preventing the induced changes. Hyperchromasia, vesicular degeneration, necrosis and infiltration with macrophages, monocytes and neutrophils were observed in the LPS-treated group (10 mg/kg, intraperitonally [i.p.]). Also, a typical structure of the glandular acini of the gland exhibited diffuse damage. In the LPS rats treated with melatonin (10 mg/kg, i.p.), a diminished number of infiltrative cells was seen, and cloudy swelling was reduced, as was nuclear hyperchromasia. Neither necrosis nor vesicular degeneration were noted in the melatonin-treated rats, and in general, glandular structure was preserved. Lipid peroxidation products increased significantly within six hours after LPS administration, and melatonin treatment decreased the LPS-dependent lipid peroxidation products. These data together suggest that melatonin protects the Harderian gland against LPS toxicity in terms of morphological damage.

Avian infectious bronchitis: viral persistence in the harderian gland and histological changes after eyedrop vaccination.

The histological changes in the harderian gland (HG) induced by the attenuated H-120 infectious bronchitis virus (IBV) vaccine strain and the persistence of this virus in the stroma of the gland was evaluated in chickens after eyedrop vaccination. Virus replication induced an increase in IBV-specific enzyme-linked immunosorbent assay antibody levels from marginal levels at vaccination (26 days of age) to significantly higher levels 10 days after exposure. IBV antigen was detected in the HG by both immunofluorescence using a monoclonal antibody and virus reisolation in embryonated chickens eggs until day 14 postvaccination. Lymphocytic, heterophilic, erythrocytic, and plasma cell infiltration as well as epithelial cell integrity in collecting tubules and acini were evaluated in the HG throughout the experimental period. IBV vaccination with the attenuated vaccine strain H-120 resulted in partial damage to the HG, as demonstrated by both the presence of plasma cells showing Russell bodies and by tubule epithelial cell exfoliation that occurs simultaneously with the presence of detectable IBV. The increase in plasma cell number and the enlargement of lymphoid foci appear to be expressions of the immunocompetence of this paraocular gland.

Hipervitaminose A experimental no rato. XVII. Estudo estereológico das alterações provocadas pela hipervitaminose A na glândula de Harder de ratos / Experimental hypervitaminosis A in the rat. XVII. Stereological study of the alterations in the Harder's gland of rats submitted to hypervitaminosis A

A hipervitaminose A induz as seguintes alterações na glândula de Harder de ratos: ácinos de menor tamanho constituídos de células mais baixas e lumen amplo, além de núcleos de menos volume quando comparadas às dos controles. Estes dados foram confirmados com técnicas estereológicas adequadas