Estrogen-induced proliferation in cultured hepatocytes involves cyclin D1, p21(Cip1) and p27(Kip1).

The purpose of this study was to establish if estrogen-induced hepatocyte proliferation in vitro involves the cell cycle regulators cyclin D1, p21(Cip1), and p27(Kip1). Male rat hepatocytes were cultured in presence of 17-beta-estradiol (E2) +/- ICI-182780, a pure estrogen antagonist, and [3H]-thymidine, as required. DNA synthesis as well as p21(Cip1), p27(Kip1), and cyclin D1mRNA and protein levels were evaluated at different times (12, 24, 36, and 48 hours) of incubation. E2-increased DNA synthesis was correlated with cyclin D1 and p21(Cip1) (mRNA and protein) variations that were reversed by the addition of ICI-182780. p27(Kip1) protein levels progressively increased regardless of the presence of E2 or ICI-182780. Our data confirm that estrogens' stimulatory effect is related to their ability to increase cyclin D1 levels. The increase of p21(Cip1) is probably related to the reentry of hepatocytes in the quiescent state. p27(Kip1) protein is not able to arrest hepatocyte proliferation.

[Epithelial leiomyosarcoma of gingiva: a case report and review of literature]. / Leiomiosarcoma epitelioide gengivale: presentazione di un caso clinico e revisione della letteratura.

Epithelioid leiomyosarcoma (EL) is a rare malignant tumor of mesenchymal origin. The Authors review the literature and report a case of gingival epithelioid leiomyosarcoma in a 40-year-old patient. In this case the leiomyosarcoma was located in the lower front dental group and invaded the symphysis menti. A segmentary mandibolectomy was performed with reconstruction using a non-revascularized autologous iliac bone graft. The differential diagnosis of primary EL is quite complex and it is grouped with other sarcomas, sarcomatoid carcinoma, myoepithelioma, amelanotic melanoma and metastases from gastrointestinal EL. Anatomopathological examination and immunohistochemical study enabled a definitive diagnosis of primary EL of gingiva. The follow-up calls for clinical-radiological check-ups every three months for the first year and every six months thereafter. One year after surgery there were no signs of recurrence.

Demonstration of a direct stimulatory effect of bile salts on rat colonic epithelial cell proliferation.

BACKGROUND: Despite the clear demonstration that an increase in faecal bile salt concentration can augment colonocyte proliferation, it is still controversial whether bile salts act on these cells as direct mitogens or by inducing a damage-related proliferative response. The goal of this study was to define the mechanism mediating the proliferative effect of bile salts on rat colonocytes. METHODS: Faecal bile salt concentration was increased by feeding rats on diets enriched with either bile salts or fats. Colonic mucosa proliferating cell nuclear antigen (PCNA) expression, histology and apoptosis, and faecal water cytolytic activity were evaluated to assess proliferation and direct or indirect signs of mucosal damage. RESULTS: Compared to standard diet, chenodeoxycholate-, deoxycholate- and fat-enriched diets produced a significant increase in both faecal water total bile salt concentration (46.0 versus 124.1, 145.9 and 498.5 micromol/L, respectively) and percentage of PCNA-positive nuclei (30.5, versus 37.7, 33.9 and 47.1, respectively) that appeared significantly correlated (r = 0.8; P < 0.001). Chenodeoxycholate and deoxycholate fed animals showed colonic mucosa histology and faecal water cytolytic activity similar to controls, with a significantly reduced apoptotic index. Rats fed on high fat diet, however, showed a mild inflammatory infiltrate associated with an increased apoptosis and faecal water cytolytic activity, all conditions not apparently determined by the increased faecal water total bile salt concentration. CONCLUSIONS: The results obtained in this study demonstrate that bile salts act as direct mitogens on colonic epithelial cells.