The effect of diabetes on Fracture Resistance of Teeth: An in vitro study.

The root fracture resistance (RFR) of premolars extracted from diabetic patients and the effect of biomaterials: white mineral trioxide aggregate (WMTA) and WMTA+Na2 HPO4 as an additive, on enhancing RFR were evaluated. Diabetic and non-diabetic teeth were divided into 4 subgroups (n = 5): root canals were obturated with WMTA, WMTA+Na2 HPO4 , gutta-percha and one unfilled (control). A plunger (1 mm diameter) applied a downward compressive load with crosshead speed of 1 mm min-1 on the specimens mounted on resin blocks, and the ultimate force to fracture was measured. The mean RFR values of diabetic specimens were significantly lower. The lowest and highest means of RFR were recorded in the control and WMTA, in normal group and the control and WMTA+Na2 HPO4 in the diabetic group, respectively. The RFR in diabetic patients was significantly lower, indicating their higher susceptibility to fracture under vertical forces. The use of WMTA (with or without Na2 HPO4 ) for obturation enhances the RFR.

Aggressive fibromatosis (desmoid tumor) is derived from mesenchymal progenitor cells.

The cellular origins from which most tumors arise are poorly defined, especially in mesenchymal neoplasms. Aggressive fibromatosis, also known as desmoid tumor, is a locally invasive soft tissue tumor that has mesenchymal characteristics. We found that aggressive fibromatosis tumors express genes and cell surface markers characteristic of mesenchymal stem cells (MSC). In mice that are genetically predisposed to develop aggressive fibromatosis tumors (Apc(wt/1638N)), we found that the number of tumors formed was proportional to the number of MSCs present. Sca-1(-/-) mice, which develop fewer MSCs, were crossed with Apc(wt/1638N) mice. Doubly mutant mice deficient in Sca-1 developed substantially fewer aggressive fibromatosis tumors than wild-type (WT) littermates, but Sca-1 deficiency had no effect on the formation of epithelial-derived intestinal polyps. MSCs isolated from Apc(wt/1638N) mice (or mice expressing a stabilized form of ß-catenin) induced aberrant cellular growth reminiscent of aggressive fibromatosis tumors after engraftment to immunocompromised mice, but WT cells and mature fibroblasts from the same animals did not. Taken together, our findings indicate that aggressive fibromatosis is derived from MSCs, and that ß-catenin supports tumorigenesis by maintaining mesenchymal progenitor cells in a less differentiated state. Protecting this progenitor cell population might prevent tumor formation in patients harboring a germline APC mutation, where fibromatosis is currently the leading cause of mortality.

Evaluation of body composition of large-for-gestational-age infants of women with gestational diabetes mellitus compared with women with normal glucose tolerance levels.

OBJECTIVE: The purpose of this study was to determine whether there is a difference in body composition and the factors that are associated with fat mass in the large-for-gestational-age infants of women with gestational diabetes mellitus compared with the large-for-gestational-age infants of women with normal glucose tolerance levels. STUDY DESIGN: Large for gestational age was defined as weight >90th percentile for gestational age, race, and sex on the basis of our population's normative data. Anthropometric measurements and/or total body electrical conductivity estimated body composition that included fat mass, percent body fat, and lean body mass were obtained. Multiple stepwise regression was used to determine factors correlating with fat mass. RESULTS: Fifty cases of women with gestational diabetes mellitus and 52 cases of women with normal glucose tolerance levels were evaluated. Infants of mothers with gestational diabetes mellitus had increased fat mass (662 vs 563 g; P = .02) and percent body fat (16.2% vs 13.5%; P = .002) but decreased lean body mass (3400 vs 3557 g; P = .0009), as compared with infants of mothers with normal glucose tolerance levels, despite similar birth weights. Stepwise regression on all 102 women showed gestational age and a diagnosis of gestational diabetes mellitus correlated with fat mass (r2 = 0.11; P = .001). For gestational diabetes mellitus alone, both gestational age and fasting value of the oral glucose tolerance test correlated with fat mass and percent body fat (r2 = 0.33 [P = .0009] and r2 = 0.26 [P = .005], respectively). CONCLUSION: Large-for-gestational-age infants of mothers with gestational diabetes mellitus have increased fat mass and decreased lean body mass compared with infants of mothers with normal glucose tolerance levels. In gestational diabetes mellitus, gestational age and fasting value of the oral glucose tolerance test correlated best with fat mass.