Alterations in diet consistency and variation in Hypoxia Inducible Factor-1α expression in condylar chondrocytes.

OBJECTIVE: To investigate the expression of HIF-1α during the postnatal development of the mandibular condyle under normal and soft consistency diet conditions. MATERIALS AND METHODS: Forty eight Wistar-Furth rats, aged 21 days, were divided into two groups, each being fed with either normal or soft consistency diet. Three animals from each group were sacrificed after 3, 7, 10 days (initial period), 14, 17 days (intermediate period), and 21, 24 and 28 days (final period) after the start of the experiment. Immediately after sacrifice, the mandible was excised surgically, fixed, demineralised and embedded in paraffin. Six µm thick sections were obtained, processed for conventional and immunohistochemical staining and observed in the optical microscope. HIF-1α expression was assessed semiquantitavely and graded separately for the nucleus stained cells and the cells stained exclusively in the cytoplasm. Differences in HIF-1α expression in the experimental groups were evaluated statistically. RESULTS: HIF-1α expression was evident in the proliferative and chondroblast layers. No differences were observed between the anterior, the intermediate and the posterior parts of the condylar cartilage. In the normal consistency diet group, nuclear HIF-1α expression increased gradually until the end of the experiment. On the contrary, in the soft diet animals, nuclear HIF-1α expression increased only at the final period of the experiment. The normal diet fed animals exhibited more intense nuclear HIF-1α expression compared to cytoplasmic expression. CONCLUSIONS: HIF-1α expression in condylar chondrocytes varies under altered conditions of diet consistency.

The effect of capecitabine on the healing of colonic anastomoses in rats.

PURPOSE: Capecitabine is a fluoropyrimidine carbamate with antineoplasmatic activity, recommended for the treatment of colorectal cancer. This study was designed to assess the effectiveness of the perioperative administration of capecitabine on the healing process of colonic anastomosis. METHODS: Sixty Wistar rats were used, which were randomized in 2 groups of 30 each. The study group was subjected to colonic anastomosis and treated with therapeutic doses of capecitabine (359 mg/kg, or 2/3 of the mean toxic dose) by mouth one week before anastomosis and throughout the study. The control group received only placebo medication. Both groups were further divided into three subgroups, each of ten animals. In both study and control groups, ten animals were killed in each session on postoperative Days 3, 7, and 14. RESULTS: We found no negative impact on the healing of colonic anastomosis on capecitabine administration. The rate of anastomotic leakage and septic complications were not found to be significantly different between the study and control groups. The median bursting pressure was found to be significantly higher in the study subgroup killed on the third day (68 vs. 46 mmHg of the control group). CONCLUSIONS: Perioperative administration of capecitabine does not have a negative impact on colonic anastomosis in rats.

Ultrastructural changes of the palatal mucosa following application of 4-nitroquinoline-l-oxide (4NQO) in rats subjected to major salivary gland excision.

OBJECTIVE: It has been suggested that saliva exerts a protective role against the carcinogenic effect of various substances in the oral cavity. The objective of this study was to examine the ultrastructural changes of the palatal mucosa caused by the application of 4-nitroquinoline-l-oxide (4NQO) in the presence or absence of saliva. STUDY DESIGN: Wistar-Furth rats subjected and not subjected to total bilateral excision of the major salivary glands were either painted with an aqueous solution of 4NQO or with propylene glycol only (controls). Two animals of each group were humanely killed periodically. The areas of the palatal lesions were immediately sliced and processed for TEM examination. RESULTS: Ultrastructurally, the progressive changes to squamous cell carcinoma were observed in the animals painted with 4NQO. In the desalivated animals group, the ultrastructural alterations appeared earlier than in the group with salivary glands. CONCLUSIONS: Saliva appeared to delay but not hinder tumor induction by 4NQO.