Influence of insulin on the healing of exposed dental pulp after pulp capping: An experimental study in a dog model.

BACKGROUND: This study investigates the influence of insulin on pulp tissue healing after pulp capping in diabetic dogs. METHODS: Diabetes mellitus was induced in four dogs, and their blood glucose levels were adjusted by insulin to normoglycemic level in two dogs (normoglycemic group) and to hyperglycemic level in two dogs (hyperglycemic group). Class V buccal cavities were performed in 15 teeth in each diabetic dog and two normal dogs (control group). The three groups (30 teeth each) were divided according to the capping materials into three subgroups (10 teeth each) including: subgroup A - mineral trioxide aggregate (MTA), subgroup B - bioaggregate (BA), and subgroup C - calcium hydroxide (Ca(OH)2 ). Each subgroup was divided into two subdivisions according to the evaluation period, subdivision 1: 1 month and subdivision 2: 2 months. Qualitative and quantitative evaluations of the inflammation and dentine bridge formation were assessed histologically. RESULTS: The hyperglycemic diabetic group exhibited significant higher inflammatory cell count and scores and lower dentine bridge thickness than those of the normoglycemic diabetic and control groups (P < .05). There were no significant differences in these parameters between the normoglycemic diabetic and control groups (P > .05). CONCLUSION: Insulin has favourable effects on the pulp tissue healing after pulp capping in diabetic dogs.

Image cytometric analysis of p53 and mdm-2 expression in primary and recurrent mucoepidermoid carcinoma of parotid gland: immunohistochemical study.

AIMS AND OBJECTIVES: This study aims to analyze immunocytochemically p53 aberrant expression and mdm-2 expression in primary and recurrent mucoepidermoid carcinoma (MEC) of parotid gland and to ascertain if expression of these markers correlates with tumor behavior, clinical outcome, histological grade and local recurrence. METHODS: 20 cases histologically diagnosed as primary MEC with different grades were included in the study. Out of 20 cases, 7 were classified as grade I, 8 as grade II and 5 as grade III. Immunohistochemical staining of these 20 primary cases as well as 6 recurrent cases with anti-p53 and anti-mdm-2 antibodies was carried out. Area fraction of immunopositivity was estimated by image analysis software. RESULTS: 16/20 primary cases were p53 +ve (80%). The p53 positive cases included 3 cases classified as grade (I), 8 cases as grade (II) and 5 cases as grade (III). All 6 recurrent cases were p53 +ve. On the other hand, 14/20 primary and only 2/6 recurrent cases were mdm-2 +ve. The mdm-2 +ve primary cases included 2 classified as grade (I), 7 as grade (II) and 5 as grade (III). 12 primary MEC showed co-expression of both p53 and mdm-2 of which 2 cases showed local recurrence. CONCLUSIONS: These data suggested that expression of p53 and mdm-2 in primary and recurrent MEC correlates with the high histological grade. P53 aberrant expression is not only considered as an early event in MEC carcinogenesis but also correlates to tumor behavior and local recurrence. Mdm-2 overexpression is correlated to pathogenesis of MEC. However, no strong evidence was found between mdm-2 expression and MEC local recurrence.

Immunohistochemical localization of mdm-2, p27Kip1 and bcl-2 in Warthin's tumor of the parotid gland.

BACKGROUND: Warthin's tumor is a benign monomorphic adenoma with unclear origin that almost occur exclusively in the parotid gland. Etiology of Warthin's tumor as well as its malignant potential are still unclear. Therefore immunohistochemical assessment of Warthin's tumor may be useful to detect its origin or its malignant transformation potential. AIMS AND OBJECTIVES: The present study aims to investigate the immunohistochemical expression of murine double minute-2 (mdm-2), p27Kip1 and B cell lymphoma-2 (bcl-2) in Warthin's tumor of parotid gland and also to clarify the role of these proteins in the behavior of that tumor. METHODS: Twenty paraffin blocks of cases previously diagnosed as Warthin's tumor were collected for immunohistochemical staining with primary antibodies against mdm-2, p27Kip1 and bcl-2 using streptavidin-biotin immunoperoxidase staining system. RESULTS: All cases showed immunopositivity for mdm-2 and p27Kip1 while 18/20 showed bcl-2 immunopositivity. Both layers of the neoplastic epithelial cells that line the cystic spaces showed immunopositivity with all antibodies used. Goblet cells were mdm-2 immunonegative while myoepithelial cells were p27Kip-1 immunonegative. Areas of epithelial proliferation that formed buds were p27Kip-1 and bcl-2 immunopositive. CONCLUSION: Mdm-2 played a tumor-suppressor role that might be implicated with the benign behavior of Warthin's tumor. The mutual expression of both p27Kip1 and bcl-2 suggested a protective role of these slowly proliferating cells from apoptosis to maintain their survival and elevated bcl-2 expression offers a significant protection against p27Kip1-mediated apoptosis.