Effect of sex steroids on bone formation in an orthopedically expanded suture in rats : An immunohistochemical and computed tomography study.

OBJECTIVE: The purpose of this work was to evaluate the effects of sex steroids on bone formation in response to midpalatal suture expansion by means of histological and immunohistochemical examinations and computed tomography (CT). MATERIALS AND METHODS: A total of 32 male and 32 female 12-week-old Wistar rats were divided into four groups per gender. Testosterone was administered to the castrated experimental male rats, estrogen to castrated experimental female rats. Saline solution was given subcutaneously to the male and female control, sham, and castration groups during expansion and retention periods, which lasted 7 and 5 days, respectively. The expansion amount was measured with a digital caliper. The density of the new bone in the expansion area was measured via CT. RESULTS: Histological and CT evaluation revealed that the number of osteoblasts and density of the new bone was higher in male and female experimental groups than in all the other groups. When scores of staining intensity were compared, the experimental groups demonstrated statistically significant greater immunoreactivity in the osteoblasts compared to castrated-only groups. Bone density was higher in the female experimental group than in the others, and higher in the male experimental group than in the others. Expansion amounts in the castrated groups were higher than in the others (p < 0.05). CONCLUSION: Raising the levels of sex steroids in rats revealed positive effects on bone formation in the midpalatal suture in response to expansion. Increased sex steroid levels can reduce the time needed for retention.

High risk of malignant mesothelioma and pleural plaques in subjects born close to ophiolites.

BACKGROUND: Ophiolites, a special sequence of geologic rock units, are known sources of naturally occurring asbestos. The aim of this study was to test whether the occurrence of malignant mesothelioma (MM) or pleural plaques (PPs) in the province of Sivas, Turkey, is determined by the proximity of the patient's birthplace to ophiolites and, if so, to establish the magnitude of the risk. METHODS: The birthplaces of patients with MM or PPs (cases) and patients with prostate or breast cancer (control subjects), diagnosed between 2000 and 2010 and identified through a mandatory cancer registry or from hospital records (PPs), were located on a geologic map, and the nearest distance to ophiolites was measured. The relation of MM or PPs with distance to ophiolites was analyzed by logistic regression. Samples of soil and house plaster were determined by x-ray diffraction. RESULTS: Patients with MM (n = 100) or PPs (n = 133) were born significantly nearer to ophiolites (median distance, 4.5 km for men, 0 km for women) than were patients with prostate cancer (n = 161) or breast cancer (n = 139) (median distance, 20 km for both). ORs were 1.6 (men) ( P < .001) and 2.0 (women) ( P < .001) for every 5-km decrease in the distance of birthplace to ophiolites for MM, compared with prostate and breast cancer, respectively. CONCLUSION: In this area without substantial industrial asbestos use, there is an association between the occurrence of mesothelioma (and of PPs) and the proximity of the subject's birthplace to ophiolites.