Oropouche virus experimental infection in the golden hamster (Mesocrisetus auratus)

Oropouche virus (OROV), of the family Bunyaviridae, is the second most frequent arbovirus causing febrile disease in Brazil. In spite of this, little is known about pathogenesis of OROV infection. This report describes an experimental model of OROV in golden hamster (Mesocricetus auratus). Following subcutaneous inoculation of OROV, over 50% of the animals developed disease characterized by lethargy, ruffled fur, shivering, paralysis, and approximately one third died. Animals were sacrificed on days 1, 3, 5, 8 and 11 post-inoculation to collect tissue samples from brain, heart, liver, lung, spleen, muscle and blood for virus titration, histology and OROV immunohistochemistry. OROV was detected in high titers in blood, liver and brain, but not in the other organs. Histopathology revealed meningoencephalitis and hepatitis, with abundant OROV antigen detected in liver and brain. Diffuse galectin-3 immunostaining in brain and liver supports microglial and Kupfer cells activation. This is the first description of an experimental model for OROV infection and should be helpful to study pathogenesis and possibly to test antiviral interventions such as drugs and vaccine candidates. (C) 2010 Elsevier B.V. All rights reserved.

The Ideal Timing for Experimental Cleft Lip Creation

Cleft lip and palate (CLP) is the most common congenital defect of the face. Many animal models have been utilized to study embryogenesis and pathogenesis of CLP, including the development of secondary anomalies and consequent deformities. However, the ideal gestational age for surgical creation of lip or palate defects in rat models has never been determined. The aim of the present study is to improve the experimental model utilizing rat fetuses, defining the most appropriate timing for creation of the lip defect model. The study was composed of three groups of fetuses undergoing surgical creation of a lip defect at the left side of the superior lip at 17.5, 18.5, and 19.5 days of gestation. Fetuses were harvested at 21.5 days of gestation (term = 22 days) and underwent macroscopic and microscopic analyses. We found that the most appropriate moment for lip defect creation was at 19.5 days, given the presence of lip depression at the site of the defect and asymmetry and retraction associated with interruption of the lip and complete reepithelialization of the borders of the defect.

Hyperbaric oxygen on the healing of ischemic colonic anastomosis - an experimental study in rats

The aim of the present study was to evaluate the effect of hyperbaric oxygen therapy (HBO(2)) on the healing process of ischemic colonic anastomoses in rats Forty Wistar rats were divided into four groups control (Group I), control and HBO(2) (Group 11), ischemia (Group III), ischemia and HBO(2) (Group IV) Ischemia was achieved by clamping four centimeters of the colonic arcade On the eighth therapy day, the anastomotic region was removed for quantification of hydroxyproline and immunohistochemical determination of metalloproteinases 1 and 9 (MMP1,MMP9) The immunohistochemical studies showed significantly larger metalloproteinase-labeled areas in Group IV compared with Group III for both MMP1 and MMP9 (p<001) This finding points to a higher remodeling activity of the anastomoses in this experimental group Additionally, animals subjected to hyperbaric oxygen therapy showed both a reduction in interstitial edema and an increase in hydroxyproline concentrations [at the anastomotic site] Therefore, we conclude that HBO(2) is indeed beneficial in anastomotic ischemia