Three-dimensional evaluation of maxillary second molar position in untreated patients with normal occlusion : Implications for preadjusted appliance prescriptions.

PURPOSE: The study was aimed at evaluating the sagittal and transversal inclinations of upper second molars in untreated adolescents with normal occlusion. METHODS: A sample of 41 subjects (16 females, 25 males) was selected from the University of Michigan Growth Study (UMGS). Digital dental casts with fully erupted second molars in occlusion were chosen (mean age 14.9 ± 1.3 years). Digital measurements were recorded with the open source software 3D Slicer ( www.slicer.org ). The digital measurements of the UMGS sample were compared with the manual measurements collected by Andrews from his sample of untreated class I subjects with normal overbite and overjet. Two mixed effect models (sagittal and transversal inclinations) were performed. The "random effect" was represented by the subjects, while the "fixed effects" were the two compared groups, the side of the arch (right and left), and the groupâ€¯× side interaction. Outcome variables were sagittal and transversal inclinations of the upper second molars. RESULTS: The UMGS group showed a significantly greater distal crown angulation (-18.9°) with respect to the Andrews sample (0.4°, P < 0.0001). As for the transversal inclination, the UMGS group exhibited significantly greater lingual crown inclination (-10.6° versus -8.0°, P = 0.0118). CONCLUSIONS: Fully erupted maxillary second molars in a sample of adolescent subjects with normal occlusion showed significantly greater distal and lingual inclinations when compared with Andrews' values. The finding of a distal crown inclination in contrast with Andrews' observation of a mesial crown inclination suggests that revision in tip prescription for preadjusted brackets may be considered.

Tissue Nonspecific Alkaline Phosphatase Function in Bone and Muscle Progenitor Cells: Control of Mitochondrial Respiration and ATP Production.

Tissue nonspecific alkaline phosphatase (TNAP/Alpl) is associated with cell stemness; however, the function of TNAP in mesenchymal progenitor cells remains largely unknown. In this study, we aimed to establish an essential role for TNAP in bone and muscle progenitor cells. We investigated the impact of TNAP deficiency on bone formation, mineralization, and differentiation of bone marrow stromal cells. We also pursued studies of proliferation, mitochondrial function and ATP levels in TNAP deficient bone and muscle progenitor cells. We find that TNAP deficiency decreases trabecular bone volume fraction and trabeculation in addition to decreased mineralization. We also find that Alpl-/- mice (global TNAP knockout mice) exhibit muscle and motor coordination deficiencies similar to those found in individuals with hypophosphatasia (TNAP deficiency). Subsequent studies demonstrate diminished proliferation, with mitochondrial hyperfunction and increased ATP levels in TNAP deficient bone and muscle progenitor cells, plus intracellular expression of TNAP in TNAP+ cranial osteoprogenitors, bone marrow stromal cells, and skeletal muscle progenitor cells. Together, our results indicate that TNAP functions inside bone and muscle progenitor cells to influence mitochondrial respiration and ATP production. Future studies are required to establish mechanisms by which TNAP influences mitochondrial function and determine if modulation of TNAP can alter mitochondrial respiration in vivo.

Effects of Improvac and Bopriva on the testicular function of boars ten weeks after immunization.

This study investigated the effects of Improvac and Bopriva, two anti-GnRF immunization products, on testicular function in boars. We predicted that both products would diminish testicular function; however, we specifically tested the hypothesis that the duration of efficacy for Bopriva would be longer than that of Improvac. Animals were immunized with either Improvac or Bopriva and then observed ten weeks after the second injection. Serum GnRF antibody titers rose after the second injection and peaked approximately two weeks later. At the same time testosterone concentrations decreased to undetectable levels and remained below assay detection for at least six weeks. At approximately eight weeks, testosterone began to increase in animals treated with Improvac though levels remained decreased in Bopriva treated animals throughout the ten weeks. Daily sperm production at 10 weeks was significantly reduced in both treatment groups; however, the reduction was greater in Bopriva treated boars. Examination of testes of both treatments revealed incomplete spermatogenesis with impaired spermatid production and reduced seminiferous tubule diameter. These findings were universal in Bopriva treated animals, but Improvac treated animals exhibited morphologies intermediate between Bopriva treated animals and control boars. Overall testicular function in Bopriva boars remained suppressed ten weeks post-immunization while Improvac boars appeared to be recovering.