Effect of Aging Time and Thickness on Low-Temperature Degradation of Dental Zirconia.

PURPOSE: To evaluate the influence of specimen thickness and low-temperature degradation (LTD) on yttrium-stabilized tetragonal zirconia polycrystals (Y-TZP). MATERIALS AND METHODS: Thin discs of Y-TZP from four manufacturers were sintered according to each manufacturer's recommendations, cut into 23 mm (length) × 4 mm (width) × 0.8 mm/1.5 mm (thickness) specimens, artificially aged under standard autoclave sterilization conditions (34°C at 0.2 MPa for 10 and 20 hours), and finally ground and polished. Tetragonal to monoclinic transformation was confirmed by X-ray diffraction (XRD) analysis. Flexural strength was measured by 3-point bending tests and Vickers hardness measurements. Fracture surfaces were examined by scanning electron microscopy (SEM). RESULTS: SEM investigation revealed that with increasing aging time, the surface defects and grain size increased, particularly in the 20-hour group. Compared with the 1.5 mm group, the 0.8 mm group showed more significant defects, irrespective of aging time. The flexural strengths of Y-TZP materials decreased with a decrease in the thickness. Moreover, LTD of Y-TZP can cause significant tetragonal to monoclinic transformation, which also results in a statistically significant decrease in the flexural strength. CONCLUSION: A thinner Y-TZP specimen was likely to present surface defects and microcracks after aging. In addition, the flexural strengths decreased with a decrease in the thickness, a notable fact for further studies.

A correlation study of ischiocavernosus muscle injury with different types of pelvic fractures and erectile dysfunction after pelvic fracture.

OBJECTIVE: To explore the correlation between ischiocavernosus muscle injury (ICMI) with different types of pelvic fractures and erectile dysfunction (ED) after pelvic fracture. DESIGN: Retrospective analysis of a prospective database. SETTING: The study was carried out at the affiliated hospital of Zunyi Medical University. PATIENTS/PARTICIPANTS: A total of 776 male patients with pelvic fracture, aged 18 to 67 years, were recruited for this study by retrospective analysis, and based on the diagnosis of ED and the presence of ICMI, the participants were divided into ED and non-ED groups as well as ICMI and non-ICMI groups. INTERVENTION: No. MAIN OUTCOME MEASUREMENTS: ICMI, the type of pelvic fracture, International Index of Erectile Function-5 scores. Computed tomography/magnetic resonance imaging scans, electromyography (motor unit potential) was used to diagnose ICMI. RESULTS: The International Index of Erectile Function-5 score was 19.7 ±â€Š5.9. The incidence of ED was 27.3%, the duration time of ED was 30 ±â€Š23 months, and the incidence of reversible ED was 39.6% and of irreversible ED was 60.4%. The incidence of ICMI was 29.4%, among which the incidence of unilateral injury was 57.9%, and the incidence of bilateral injury was 42.1%. Among all pelvic fractures, the incidence of pubic ramus fracture was 88.1%. Bilateral pubic ramus fractures, bilateral fractures of the ischial ramus, and ICMI were independent risk factors for ED after pelvic fracture. Bilateral pubic ramus fractures and pubic symphysis separation were independent risk factors for ICMI. Unilateral ICMI was an independent risk factor for reversible ED, while bilateral ICMI was an independent risk factor for irreversible ED. CONCLUSIONS: ICMI is associated with ED and may be a cause for ED, while pubic ramus fracture, ischial ramus fracture, and pubic symphysis separation may be the main causes of ICMI. Unilateral ICMI may be the main risk factor for transient ED, and bilateral ICMI may be the main risk factor for permanent ED.

Impact of immunosuppressive agents on the expression of indoleamine 2,3-dioxygenase, heme oxygenase-1 and interleukin-7 in mesangial cells.

Chronic allograft nephropathy (CAN) is a major cause of graft loss following kidney transplantation and may result from the interactions of various immune and non-immune factors. The aim of the present study was to establish an in vitro model of glomerular mesangial cell injury in order to examine the gene expression levels of indoleamine 2,3-dioxygenase (IDO), heme oxygenase-1 (HO-1) and interleukin-7 (IL-7) in mesangial cells during the healing process as well as to investigate the effects of various immunosuppressants on the expression of these genes. The HBZY-1 glomerular mesangial cell line was pre-treated in vitro with cytochalasin B for 2 h to induce reversible damage. Following the pre-treatment, the HBZY-1 cells were divided into five groups: Blank control group, cyclosporine A (CsA) group, tacrolimus (Tac) group, mycophenolate mofetil (MMF) group and rapamycin (RAPA) group. After treating the mesangial cells with each immunosuppressive drug for 6, 12 or 24 h, the mRNA and protein expression levels of IDO, HO-1 and IL-7 were examined using reverse transcription quantitative polymerase chain reaction (RT-qPCR), western blot and immunohistochemical analyses. The results showed that expression levels of HO-1 were significantly upregulated in response to treatment with CsA, FK506, RAPA and MMF, whereas the expression levels of IL-7 were markedly downregulated by treatment with the above immunosuppressants. CsA, FK506 and MMF significantly enhanced the expression levels of IDO, whereas RAPA exhibited no apparent effect on IDO. The present study may contribute to the understanding of the pathogenesis of CAN and provide novel strategies for the prevention and treatment of CAN.