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The present study describes the pathogenetic mechanisms of myocarditis in 9 lambs that died in a foot-and-mouth disease outbreak in Samsun, Turkey. In all the heart samples tested, ELISA and sequencing for phylogenetic analyses showed that the virus, namely O/TUR/Samsun/05, was associated with the PanAsia pandemic strain of foot-and-mouth disease virus (FMDV) type O. The lambs had myocardial lesions but no typical vesicular lesions. In situ reverse transcription showed that many cardiomyocytes and some interstitial cells were positive for FMDV type O. Inflammatory infiltration, hyaline degeneration, and necrosis of sheets of myocytes were observed. The cellular infiltrates were mononuclear cells, including many lymphocytes, macrophages, a few plasma cells, and neutrophils. Major histocompatibility complex Class II+ dendritic and mononuclear cells, gammadelta T cells, CD172A+ and CD14+ macrophages and monocytes, and IgM+ B cells were detected mainly in the infected hearts. Inducible nitric oxide synthetase (iNOS) was seen mostly in areas of inflammation infiltrated by large numbers of cells. Of the 2 alpha-subunits of integrin known to be used as receptors by FMDV in epithelial tissues, CD49e (integrin alpha5) was detected in the membranes of cardiac myocytes with intercalated discs, but CD51 (integrin alphaV) was not detected in cardiac myocytes from infected or normal lambs. Interstitial and inflammatory cells were positive for both integrin subunits. The terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL)-positive signal was detected in the nuclei of both cardiac myocytes and interstitial cells from infected lambs. These findings suggest that the iNOS expressed by inflammatory cells in lesions may have a deleterious effect on cardiac myocytes in these lesions.

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Considerable evidence supports the hypothesis that melatonin plays an important role in osteogenesis. We carried out an experiment to investigate histological and radiological changes in the cervical vertebrae of pinealectomized chickens. Thirty new-hatched chicks were divided into two groups: pinealectomized group (n=15) and nonpinealectomized control (n=15). Surgical pinealectomies were performed in Hybro broiler chickens at the age of 3 days. At 8 wk, one animal from each group was examined using computed tomography scanner to obtain density histograms of four consecutive vertebrae between the 4th and 7th cervical vertebral segments of chickens. At the end of the study, all animals were killed for subsequent measurement of bone mineral density (BMD) and macroscopic, radiographic and histopathological evaluation of specimens. We found that the profile of the density histogram in nonpinealectomized control group showed a spike profile for the vertebral body, indicating an increase in the amount of higher density tissues in this region, while a plateau-shaped profile was obtained for the vertebral body in pinealectomy group, indicating the presence of heterogenous bone tissue. Accordingly, the mean value of BMD in pinealectomy group was significantly lower at the vertebral body in chickens compared with control subjects (P<0.001). At the end of the experiment, almost all of the chickens in pinealectomy group developed a scoliotic curvature and the mean weight and length of the cervical vertebral bodies of the pinealectomized chickens were significantly lower than those of control group (P<0.001). Although the numerical density of osteocytes and osteoblasts in pinealectomy group was significantly higher than that from the control group, total number of osteocytes but not osteoblasts in cervical vetrebrae from pinealectomized animals was significantly lower than that from nonpinealectomized control animals (P<0.05). In conclusion, the results of the current study demonstrated for the first time pinealectomy-induced histomorphometrical changes in chicken vertebral column using stereological methods, suggesting that pineal gland/melatonin may have an osteoinductive effect on bone formation, but further studies are needed to elucidate the relationship of our findings with some disorders such as postmenopausal and/or senile osteoporosis.

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