Canine hemangiopericytomas: cell proliferation and apoptosis in the perivascular, storiform and epithelioid histological subtypes and their significance for prognosis

Canine hemangiopericytomas (CHP) are soft tissue neoplasms, originary from pericytes. They are frequently diagnosed in dogs and can be seen more frequently in limbs as circumscribed and firm nodules. The histopathology of CHP reveals the presence of spindle cells around blood vessels, forming whorls. In this study, cases of CHP from the Animal Pathology Service of the Veterinary Hospital of the School of Veterinary Medicine and Animal Science, registered from 1990 to 2003, were studied. All cases were reviewed and classified in the three histological subtypes recently described perivascular (PVHP), storiform (SHP) and epithelioid (EHP). Immunohistochemical markers (vimentin, S-100 protein, CD34, Factor VIII and glial fibrillary acidic protein GFAP) were applied to all tumors. Samples were submitted to the immunostaining of PCNA, and the labeling indexes were obtained. The mitotic index was also quantified in each subtype. Apoptosis bodies were morphologically identified in H&E stained sections, subsequently confirmed by fluorescence microscopy and then quantified in the three histological subtypes. Dog owners were contacted by telephone, and asked to inform about the outcome of their dogs. The survey revealed 61 cases of CHP, in which 21 (34.43.%) belonged to the perivascular subtype, 18 cases (29.51.%) belonged to the storiform subtype, and 22 cases (36.06.%) belonged

Compensatory kidney hypertrophy/hyperplasia after nephrectomy in mice: alterations of connexin 43 (Cx43) phosphorylated isoforms

Compensatory kidney hypertrophy/hyperplasia leads to several changes in kidney structure and function, as increased glomeruli filtration. The aim of this study was to evaluate connexin 43 in remnant mouse kidneys after unilateral nephrectomy. The right kidney was surgically removed from BALB/c mice. Groups were euthanized at 24, 48 and 72 hours, and at 7 and 30 days. Kidney sections of the reminiscent kidneys were stained with Periodic Acid/Schiff and additional slides were submitted to BrdU and Cx43 immunohistochemistry. The results demonstrated an increase in kidney weight as early as 24 hours through 30 post-nephrectomy. In addition, BrdU positive epithelial cells increased at 24 and 48 hours post-nephrectomy. Cx43 was detected in the cytoplasm and membrane of epithelial cells and vasculature. Taking into consideration the quantity, intensity and localization of Cx43 immunostaining pattern, we observed that nephrectomized mice presented lower Cx43 expression and a cytoplasmic localization after 24 hours, peaking in 48 hours. Furthermore, western blot revealed that during the first 24 and 48 hours after nephrectomy, P0 (unphosphorylated) and P1 (phosphorylated) Cx43 disappeared, and the products of Cx43 degradation were reduced. On the other hand, after 72 hours the P0 and P1 state reappeared and the amount of degraded peptides also increased. Seven and thirty days after neph