Response to Mechanical Cues by Interplay of YAP/TAZ Transcription Factors and Key Mechanical Checkpoints of the Cell: A Comprehensive Review.

Many factors including growth factors (GF), scaffold materials, and chemical and physical cues determine the cell behaviors. For many years, growth factors have been considered as the pivotal cell behavior regulators, whereas recent studies emphasize also the key role of physical factors such as mechanical forces, cell shape, surface topographies, and extracellular matrix (ECM) in regulating the cell proliferation, apoptosis, differentiation, etc. through mechanotransduction pathways. In this process, the cell morphology and mechanical properties of the cell's micro/ nano-environments and ECM can be conveyed to the nucleus by regulating transcriptional factors such as Yes-associated protein and transcriptional coactivator with PDZ-binding motif (TAZ). Generally, YAP/TAZ activity is considered as the key factor for the growth of whole organs, however, recent studies have also repeatedly addressed the role of YAP/TAZ in mechanotransduction. In this review, the biological functions of the YAP/TAZ pathway and its contribution to the mechanotransduction and cell behavior regulation in response to the mechanical cues have been summarized. Also, the role of key mechanical checkpoints in the cell including focal adhesions, cytoskeletal tension, Rho small GTPases, and nuclear membrane protein elements involved in the transfer of environmental mechanical cues from the cell surface to the nucleus and their effect in regulating the YAP/TAZ activity are discussed.

Characteristics of Medial Depression of the Mandibular Ramus: A CBCT Analysis in Different Sagittal Skeletal Patterns.

Statement of the Problem: Medial depression of the mandibular ramus (MDMR) as a normal anatomical variation might complicate orthognatic surgeries that involve ramus. When planning an orthognatic surgery, it is clinically valuable to notice MDMR in osteotomy site to decrease the risk of failure. Purpose: The aim of present study was to evaluate the prevalence as well as characteristics of MDMR in three skeletal sagittal classifications. Materials and Method: This cross sectional study evaluated 530 cone beam computed tomography (CBCT) scans, of which 220 were enrolled. The skeletal sagittal classification, the presence of MDMR, the shape, depth, and width of MDMR were recorded for each patient by two examiners. Chi-square test was performed to determine the differences between three skeletal sagittal groups and between two genders. Results: The overall prevalence of MDMR was 60.45%. MDMR was mostly detected in class III (76.92%), followed by class II (76.66%), and class I (54.87%). In the analyzed CBCT scans, semi-lunar was the most common shape detected (42.85%), followed by triangular (30.82%), circular (18.04%), and tear-drop (8.27%). The depth of MDMR was not significantly different between three sagittal groups and between genders; however, the width of MDMR was higher in class III group and in male patients. In the present study, MDMR was found to be more common in patients with class II and class III skeletal classifications. Although, MDMR was more frequent in class III, the difference between class II and class III was not significant. Conclusion: More caution is needed during orthognatic surgery in patients with dentoskeletal deformities during the splitting of the ramus. Moreover, higher width of MDMR in class III and male patients should be concerned when planning an orthognatic surgery for these patients.

One Side Ovarian Rejuvenation: A Quasi-Experimental Study of the Effect of the Autologous Platelet Rich Plasma in Poor Ovarian Responders in IVF.

Background: The poor ovarian response is the most important limiting factor in the success of in vitro fertilization (IVF). The aim of this study was to evaluate the outcome of intraovarian injection of autologous platelet-rich plasma (aPRP) on the oocyte number and IVF outcomes in poor ovarian responders (POR). Methods: This quasi-experimental study was performed from August 2021 to December 2021, in Vali-e-Asr Infertility Clinic affiliated with Tehran University of Medical Sciences, Tehran, Iran. There were 12 POR patients selected based on the criteria of Bologna group 4 who underwent two IVF cycles with similar antagonist regimens in a 70-day-interval. Immediately after the Oocytes Pick-Up (OPU), there was a 4cc of autologous PRP multifocal intramedullary injection done into their right ovaries in the first IVF cycle (case group). On the other hand, their left ovaries were considered as the control group. The patients underwent the second IVF cycle after 70 days. Results: Those who had undergone aPRP experienced a significant increase of the mean of antral follicular count (AFC) (from 1.91±0.79 to 2.50±0.90, p=0.043). There was a significant increase in the number of embryos from the right ovary (intervention group) compared to the left ovary (control group) after PRP, but there was no significant difference in the number of embryos in the right ovary before and after the intervention (from 0.25 ±0.45 to 1.08±0.79, p=0.705). There was no significant change in the number of oocytes, AMH, and FSH in the case and control groups before and after the intervention (p>0.05). Conclusion: According to the results of this study, it seems that in females with POR, intraovarian aPRP had no effect on the outcomes (embryos number, number of oocytes, FSH and AMH level), except for an increase in AFC.