Oral Bone Grafting in a Rat Model and the Use of Scanning Electron Microscopy for Tissue Morphology Evaluation

Oral bone grafting is a procedure widely performed in current dentistry. Several biomaterials fit this purpose.  The aim of this study was to use scanning electron microscopy (SEM) to evaluate the ultrastructural  aspects of bone repair in a rat model, with periodontal tissues involved. Two groups (I and II) of 20 animals  each were operated on to create a surgical defect with a round carbide burr (3mm) on the right side  of their mandible, anterior to the mental foramen. Both groups were evenly divided with 5 animals each to  receive the application of either bifasic calcium phosphate bioceramic (B), lyophilized deproteinated  bovine bone (L), bifasic bioceramic associated with lyophilized deproteinated bovine bone (BL), or no biomaterial  (control or C). Group I was monitored for one week and group II for three weeks prior to euthanasia.  Hemi-mandibles were prepared for SEM analysis. Parameters such as exposure of incisive root surface,  width of the cross-section of filiform structures and presence of mineralized-like globuli (area) were evaluated.  The findings of this study suggested that surgical procedures for introduction or not of biomaterial  did not cause problems with normal feeding to the animals. Both of the biomaterials used promoted a periodontal  ligament involvement. Fibers (single filiform structures) could be detected in a range from 0.07 to  0.18μm of diameter, except for L that was larger – considered to be due to residual fibers of bovine origin.  C bundles (groups of fibers) showed larger width of cross-section than with the use of biomaterials.  Globuli areas (mineralization) were smaller to C than with the biomaterials use. B showed larger globuli  areas, suggesting slow incorporation. It was concluded that the use of these biomaterials favored maintenance  of tissue volume although slowing remodeling, and the combination (BL) presented the best performance.

mTOR Controls Ovarian Follicle Growth by Regulating Granulosa Cell Proliferation

We have shown that inhibition of mTOR in granulosa cells and ovarian follicles results in compromised granulosa proliferation and reduced follicle growth. Further analysis here using spontaneously immortalized rat granulosa cells has revealed that mTOR pathway activity is enhanced during M-phase of the cell cycle. mTOR specific phosphorylation of p70S6 kinase and 4E-BP, and expression of Raptor are all enhanced during M-phase. The predominant effect of mTOR inhibition by the specific inhibitor Rapamycin (RAP) was a dose-responsive arrest in the G1 cell cycle stage. The fraction of granulosa cells that continued to divide in the presence of RAP exhibited a dose-dependent increase in aberrant mitotic figures known as anaphase bridges. Strikingly, estradiol consistently decreased the incidence of aberrant mitotic figures. In mice treated with RAP, the mitotic index was reduced compared to controls, and a similar increase in aberrant mitotic events was noted. RAP injected during a superovulation regime resulted in a dose-dependent reduction in the numbers of eggs ovulated. Implications for the real-time regulation of follicle growth and dominance, including the consequences of increased numbers of aneuploid granulosa cells, are discussed

Dental Implant Placement with Simultaneous Anterior Maxillary Reconstruction with Block and Particulate Fresh Frozen Allograft Bone: A Case Report with 24-Month Follow-Up Data

Fresh frozen allograft bone is routinely used in orthopedic surgery for the reconstruction of large bone defects, and its use in oral and maxillofacial surgery is increasing. The purpose of this case was to demonstrate the installation of dental implants and the use of fresh frozen bone for reconstruction of anterior maxilla in the same surgery. This case report presents the insertion of dental implants followed immediately by a placement of fresh frozen allograft in block and particle for a reconstruction of atrophic anterior maxillary in the same surgery. Ten months subsequent to this procedure, provisional fixed prosthesis was installed on the implants. Four months later (postoperative month 14), the final fixed prosthesis was installed and the clinical success was observed. The insertion of dental implants followed immediately by a placement of fresh frozen allograft is a safe and efficient process that results in the successful return of dental function and aesthetic rehabilitation for the patient

Variation in the ovarian reserve Is linked to alterations in intrafollicular estradiol production and ovarian biomarkers of follicular differentiation and oocyte quality in cattle

The mechanisms whereby the high variation in numbers of morphologically healthy oocytes and follicles in ovaries (ovarian reserve) may have an impact onovarian function, oocyte quality, and fertility are poorly understood. The objective was to determine whether previously validated biomarkers for follicular differentiation and function, as well as oocyte quality differed between cattle with low versus a high antral follicle count (AFC). Ovaries were removed (n = 5 per group) near the beginning of the nonovulatory follicular wave, before follicles could be identified via ultrasonography as being dominant, from heifers with high versus a low AFC. The F1, F2, and F3 follicles were dissected and diameters determined. Follicular fluid and thecal, granulosal, and cumulus cells and the oocyte were isolated and subjected to biomarker analyses. Although the size and numerous biomarkers of differentiation, such as mRNAs for the gonadotropin receptors, were similar, intrafollicular concentrations of estradiol and the abundance of mRNAs for CYP19A1 in granulosal cells and ESR1, ESR2, and CTSB in cumulus cells were greater, whereas mRNAs for AMH in granulosal cells and TBC1D1 in thecal cells were lower for animals with low versus a high AFC during follicle waves. Hence, variation in the ovarian reserve may have an impact on follicular function and oocyte quality via alterations in intrafollicular estradiol production and expression of key genes involved in follicle-stimulating hormone action (AMH) and estradiol (CYP19A1) production by granulosal cells, function and survival of thecal cells (TBC1D1), responsiveness of cumulus cells to estradiol (ESR1, ESR2), and cumulus cell determinants of oocyte quality (CTSB)