Contribution of mesenchymal proliferation in tooth root morphogenesis.

In mouse tooth development, the roots of the first lower molar develop after crown formation to form 2 cylindrical roots by post-natal day 5. This study compared the morphogenesis and cellular events of the mesial-root-forming (MRF) and bifurcation-forming (BF) regions, located in the mesial and center of the first lower molar, to better define the developmental mechanisms involved in multi-rooted tooth formation. We found that the mesenchyme in the MRF showed relatively higher proliferation than the bifurcation region. This suggested that spatially regulated mesenchymal proliferation is required for creating cylindrical root structure. The mechanism may involve the mesenchyme forming a physical barrier to epithelial invagination of Hertwig's epithelial root sheath. To test these ideas, we cultured roots in the presence of pharmacological inhibitors of microtubule and actin polymerization, nocodazole and cytochalasin-D. Cytochalasin D also inhibits proliferation in epithelium and mesenchyme. Both drugs resulted in altered morphological changes in the tooth root structures. In particular, the nocodazole- and cytochalasin-D-treated specimens showed a loss of root diameter and formation of a single-root, respectively. Immunolocalization and three-dimensional reconstruction results confirmed these mesenchymal cellular events, with higher proliferation in MRF in multi-rooted tooth formation.

Capsaicin protects against ethanol-induced oxidative injury in the gastric mucosa of rats.

In this study, we investigated the protective effects of capsaicin on gastric mucosal oxidative damage induced by ethanol. Sprague Dawley rats intragastrically received 0.5-10 mg/kg, BW capsaicin or vehicle; 30 min later gastric lesions were induced by intragastric administration of absolute ethanol. Lipid peroxidation was estimated by measuring thiobarbituric acid reactive substances in gastric mucosa. Myeloperoxidase activity, a marker enzyme of polymorphonuclear leukocytes for tissue inflammation, was also measured in the gastric mucosa. The expression level of cyclooxygenase-2, which increases in inflammatory region, was determined by Western blot analysis. Capsaicin significantly suppressed gastric haemorrhagic erosions induced by ethanol. Capsaicin inhibited lipid peroxidation and myeloperoxidase activity in ethanol-induced gastric mucosal lesion in a dose-dependent manner. Capsaicin also inhibited the expression of cyclooxygenase-2 in the gastric mucosal lesion. The gastroprotective activity of capsaicin on the ethanol-induced oxidative damage may be important for chemoprevention.

Serum antioxidative vitamin levels and lipid peroxidation in gastric carcinoma patients.

Serum antioxidative vitamin levels and lipid peroxidation in gastric cancer patients were compared with values for age-matched healthy subjects. Blood samples were collected from the stomach of cancer patients scheduled for surgical removal of their tumor. Serum ascorbic acid, alpha-tocopherol, beta-carotene, and retinol in serum were determined by high-performance liquid chromatography, and malondialdehyde levels were analyzed spectrophotometrically. General health characteristics and taste preference for spicy and/or salty food were assessed by a self-administered questionnaire. Significant decreases in serum ascorbic acid and beta carotene were observed in stomach cancer patient as compared to the control group. The levels of ascorbic acid in patients with gastric carcinoma were less than one-fifth of the control. Beta carotene and alpha-tocopherol levels in the serum of the cancer patients were significantly decreased compared to the control group, but there were no differences in retinol between the groups. Serum malondialdehyde levels were significantly higher in the cancer patients than in controls. The levels of ascorbic acid and alpha-tocopherol tend to be lower in the patient with a preference for spicy and salty food than in others without the preference. Our results demonstrate that a correlation existed between the levels of serum ascorbic acid and beta carotene, alpha-tocopherol and lipid peroxidation in gastric carcinoma.