4 research outputs found
Action Mechanism of Inhibin α-Subunit on the Development of Sertoli Cells and First Wave of Spermatogenesis in Mice
Inhibin is an important marker of Sertoli cell (SC) activity in animals with impaired spermatogenesis. However, the precise relationship between inhibin and SC activity is unknown. To investigate this relationship, we partially silenced both the transcription and translation of the gene for the α-subunit of inhibin, Inha, using recombinant pshRNA vectors developed with RNAi-Ready pSIREN-RetroQ-ZsGreen Vector (Clontech Laboratories, Mountain View, Calif). We found that Inha silencing suppresses the cell-cycle regulators Cyclin D1 and Cyclin E and up-regulates the cell-cycle inhibitor P21 (as detected by Western blot analysis), thereby increasing the number of SCs in the G1 phase of the cell cycle and decreasing the amount in the S-phase of the cell cycle (as detected by flow cytometry). Inha silencing also suppressed Pdgfa, Igf1, and Kitl mRNA levels and up-regulated Tgfbrs, Inhba, Inhbb, Cyp11a1, Dhh, and Tjp1 mRNA levels (as indicated by real-time polymerase chain reaction [PCR] analysis). These findings indicate that Inha has the potential to influence the availability of the ligand inhibin and its antagonist activin in the SC in an autocrine manner and inhibit the progression of SC from G1 to S. It may also participate in the development of the blood–testis barrier, Leydig cells, and spermatogenesis through its effect on Dhh, Tjp1, Kitl, and Pdgfa. Real-time PCR and Western blot analyses of Inha, Inhba, and Inhbb mRNA and Inha levels over time show that Inha plays an important role in the formation of round spermatid during the first wave of spermatogenesis in mice
WNT4 mediates estrogen receptor signaling and endocrine resistance in invasive lobular carcinoma cell lines
Retention of fiber-post not affected by cements but cyclic loading
Objective: To compare the micro-push-out bond strengths of a fiber-post cemented with two dentine adhesive systems in extracted human teeth with and without simulated occlusal loading. Methods: Human extracted, single-rooted teeth were decoronated above the CEJ to a standard length, root canal-treated, and then randomly divided into four groups (n=16 each). A fiber-reinforced root canal post system (Radix; Dentsply Maillefer) was cemented either with a chemically cured (Panavia F; Kuraray) or a self-etch self-adhesive resin composite cement (SmartCem2; Dentsply Maillefer) according to the manufacturer instructions, followed by a resin composite build-up to a standard shape. A layer of silicon sealant was painted over the root surface to about 2 mm below the CEJ, to imitate the periodontal ligament before embedding the root in mold for simulated occlusal loading. A total of 120,000 load cycles up to 70 N were applied for each tooth. Then, the roots were horizontally sectioned into slices of about 1 mm thick. Push-out test was performed at a cross-head speed of 1 mm/min in a universal testing machine (Instron). Data was analyzed using one-way ANOVA and two-sample t-test, where appropriate, at a significance level of 0.05. Results: No significant difference was found in the micro-push-out bond strengths at various horizontal levels for specimens of each individual group (ANOVA, P > 0.05). Panavia and SmartCem2 demonstrated similar bond strengths without loading (14.0±5.3 and 15.5±7.2 MPa, respectively). There was a significantly reduction in bond strength for both materials due to the simulated loads (P < 0.05). After loading, Panavia (5.9±3.3 MPa) showed a significantly lower bond strength than SmartCem2 (13.0±7.8 MPa) (P < 0.001). Conclusion: While the “static” bond strength for retaining a fiber-post is comparable, the two types of resin cement are both adversely and significantly affected by functional loads, but to different extents.The 88th General Session & Exhibition of the International Association of Dental Research (IADR), Barcelona, Spain, 14-17 July 2010