Two-Dimensional Terahertz Spectroscopy of Nonlinear Phononics in the Topological Insulator MnBi_{2}Te_{4}.

The interaction of a single-cycle terahertz electric field with the topological insulator MnBi_{2}Te_{4} triggers strongly anharmonic lattice dynamics, promoting fully coherent energy transfer between the otherwise noninteracting Raman-active E_{g} and infrared (IR)-active E_{u} phononic modes. Two-dimensional terahertz spectroscopy combined with modeling based on the classical equations of motion and symmetry analysis reveals the multistage process underlying the excitation of the Raman-active E_{g} phonon. In this nonlinear combined photophononic process, the terahertz electric field first prepares a coherent IR-active E_{u} phononic state and subsequently interacts with this state to efficiently excite the E_{g} phonon.

H3K27me3 may be associated with Oct4 and Sox2 in mouse preimplantation embryos.

As a core member of polycomb repressive complex 2, the transcription and enzyme activity of enhancer of zeste homolog 2 (Ezh2) is directly involved in the trimethylation of lysine 27 on histone H3. In this study, the fluorescence intensity of H3K27me3 in mouse in vivo morulae and blastocysts was compared by indirect immunofluorescence staining. We found that demethylation of H3K27me3 occurred during the blastocyst stage. Real-time polymerase chain reaction was performed to investigate Ezh2 expression in oocytes and in preimplantation embryos. Ezh2 expression peaked during the zygote stage and gradually decreased from the 2-cell stage, exhibiting an inverse pattern when compared with Oct4 and Sox2 mRNA in mouse preimplantation embryos. To understand the role of development-related genes on the transcription of mouse Ezh2, a promoter assay was performed in NIH/3T3 cells. Ezh2 expression was markedly suppressed by Oct4 and Sox2 alone in a dose-dependent manner, while Ezh2 promoter activity in co-transfection with Nanog, Klf-4, and c-Myc groups showed no significant change as compared with the control. Our data suggest that the demethylation of H3K27me3 is caused by the degressive expression and activity of Ezh2 in blastocysts, leading to increased expression of developmentally important transcription factors. We also observed negative effects of Oct4 and Sox2 on the transcription of Ezh2 and identified Oct4 and Sox2 as novel negative regulators of Ezh2 at the post-translation level in a mouse preimplantation embryo.

Alveolar bone loss around incisors in Class I bidentoalveolar protrusion patients: a retrospective three-dimensional cone beam CT study.

OBJECTIVES: The aim of this study was to test the null hypothesis that there is no difference in the alveolar bone thickness, bone loss or incidence of fenestrations between upper and lower incisors in skeletal Class I bidentoalveolar protrusive patients before orthodontic treatment. METHODS: Three-dimensional (3D) cone beam CT (CBCT) images were taken of 24 patients from the Republic of Korea (17 females and 7 males). Reformatted CBCT images were used to measure labial and lingual alveolar bone thickness (ABT) of the 4 upper incisors and 4 lower incisors of the 24 patients (total n = 192 incisors) at every 1/10 of root length (Level 0, cementoenamel junction (CEJ) area; Level 10, root apex area) as well as alveolar bone area (ABA) and alveolar bone loss (%BL) rate to dental root length. The numbers of fenestration teeth were also tallied. RESULTS: All anterior teeth were supported by <1 mm of ABT on the labial surfaces up to root length Level 8. ABA was statistically greater on the lingual aspect than the labial aspect in lower incisors. The %BL was 26.98% in the lower labial region, 19.27% in upper labial aspect and most severe on the lower lingual plate 31.25% compared with the labial plate. There were no significant differences in %BL between subgroups when categorized by sex or age. Fenestrations were 1.37 times more frequent on lower incisors (37) than upper incisors (27). CONCLUSION: The null hypothesis was rejected, confirming that incisor periodontal support is poor and alveolar bone loss is severe even prior to the start of orthodontic treatment. Careful diagnosis using 3D CBCT images is needed to avoid iatrogenic degeneration of periodontal support around anterior teeth, particularly in the lower lingual bone plate region.

Lodox/Statscan facilitates the early detection of commonly overlooked extracranial injuries in patients with traumatic brain injury.

INTRODUCTION: Traumatic brain injury (TBI) is a common diagnosis in the emergency department. Brain computed tomography (CT) has become a standard diagnostic tool with which to examine TBI patients. Conventional X-rays are ineffective for the evaluation of torso or extremity injuries. In the current study, we attempted to establish a diagnostic modality to evaluate systemically initially unconscious patients in the emergency department with a rapid screening technique characterized by sufficient information, low cost and low radiation exposure. MATERIALS AND METHODS: From January 2008 to December 2009, patients with diminished level of consciousness received the Lodox/Statscan for evaluation of extracranial injuries were enrolled in this study. The accuracy of this diagnostic modality in detecting torso or extremity injuries in initially unconscious patients was analyzed by comparing the initial diagnosis (by the Lodox/Statscan) with the final diagnosis (confirmed by torso CT scan or after two weeks of follow-up). RESULTS: There were 1,210 patients with TBI whose extracranial injuries were evaluated by the Lodox/Statscan. After excluding intra-abdominal injuries, the overall sensitivity rates of the Lodox/Statscan in diagnosing torso injuries and extremity injuries were 89.7% and 90.2%, respectively. No long bone fracture was missed by the Lodox/Statscan. The sensitivity and specificity of the Lodox/Statscan in diagnosing long bone fractures were both 100%. Most patients with torso injuries that were missed by the Lodox/Statscan could be managed conservatively without further treatment or complications. All of the missed extremity injuries were distal bone fractures. CONCLUSION: The Lodox/Statscan can provide benefits for surveying extracranial injuries in patients with diminished level of consciousness. The Lodox/Statscan also emits a notably low dose of radiation and appears to be a relatively inexpensive adjunct to screen torso or extremity injuries in TBI patients.

Polytetrafluoroethylene patch venoplasty for outflow reconstruction in living donor liver transplantation: two case reports.

Outflow obstruction may lead to liver congestion and eventual graft failure after living donor liver transplantation. Various methods of venoplasty provide wider outflow tracts. Most series have suggested use of autologous or allogenic grafts for patch venoplasty. We used a polytetrafluorethylene patch in two patients. Both showed good patency of the outflow tract at Doppler ultrasonography at 7 months and 4 months posttransplantation. A polytetrafluoroethylene patch may be a good alternative when no other autologous or allogeneic vascular patch is available or when the situation is critical.

Stimulation of embryo hatching and implantation by prostacyclin and peroxisome proliferator-activated receptor delta activation: implication in IVF.

BACKGROUND: Successful IVF depends in part on quality embryos. Recent work suggests that prostaglandin I(2) (PGI(2) or prostacyclin) promotes the development of embryos in vitro and enhances their implantation potential. The mechanism underlying the effects of PGI(2) is unclear. It has been reported that peroxisome proliferator-activated receptor delta (PPARdelta) mediates the effects of PGI(2) at the implantation sites. METHODS: The expression of PPARdelta in the preimplantation embryos was examined by RT-PCR, western blot analysis and immunohistochemistry. Synthetic PPARdelta ligand (L-165041) and PPARdelta targeted (PPARdelta(-/-)) embryos were used to reveal the roles of PPARdelta in PGI(2)-stimulated and spontaneous embryo development. RESULTS: Preimplantation embryos express PPARdelta, which is essential for the enhancing effect of PGI(2) and the spontaneous progression of preimplantation embryos. Enhanced blastocyst hatching by PGI(2) (P < 0.05) was abrogated by PPARdelta deletion. Blastocyst formation and embryo hatching were impaired in PPARdelta(-/-) embryos. PPARdelta deletion significantly reduced embryo cell proliferation (P < 0.01); PPARdelta activation increased embryo cell proliferation (P < 0.05). PPARdelta activation enhanced the implantation of wild-type (WT) embryos (P < 0.05); PPARdelta deletion reduced embryo implantation (P < 0.05). CONCLUSIONS: PPARdelta is essential for spontaneous and PGI(2)-stimulated embryo development and blastocyst hatching. The implantation of cultured embryos is enhanced by PPARdelta activation. PPARdelta represents a novel therapeutic target to improve IVF outcome.

Effects of intrahepatic canine islet autotransplantation on the portal vein pressure and liver function.

Currently, the most common method used for human islet transplantation is intrahepatic implantation via the portal vein, which may affect portal vein pressure and liver function. The aim of this study was to investigate the effects of intrahepatic canine islet autotransplantation on portal vein pressure and liver function. After total pancreatectomy was performed in 30 mongrel dogs, islets were isolated and transplanted back into the portal vein of the same dog. In our series, 12 dogs achieved normoglycemia (fasting glucose <200 mg/dL) without exogenous insulin after transplantation. The portal vein pressure increased from 4.6 +/- 1.5 to 7.7 +/- 2.9 cm H(2)O after islet infusion (P < .05). Alanine transferase amino transferase (ALT) levels gradually increased after pancreatectomy with the peak at 4 weeks after islet infusion. But the changes of portal vein pressure and ALT were not significantly different between successful and failed islet transplantation. In summary, elevation of portal vein pressure and liver enzymes were noted after intrahepatic canine islet autotransplantation. However, they did not influence the transplant outcome.

Prostacyclin enhances the implantation and live birth potentials of mouse embryos.

BACKGROUND: Recently we reported that iloprost, a stable analogue of prostacyclin, enhanced mouse embryo hatching. Here we present a follow-up study to determine whether exposure to iloprost augments the implantation and live birth potentials of mouse embryos. METHODS: Two-cell embryos (C3B6F1) were harvested 42 h after HCG injection and cultured in medium supplemented with iloprost. After 48 h, the embryos were transferred to 2.5 day pseudopregnant gestational carriers. The number of gestation sacs was counted 72 h later; the number of live pups and the weight of pups and placentae were determined 14 days later. The implantation rate was defined as gestation sac per embryo transferred; the live birth rate was defined as live pup per embryo transferred. RESULTS: The prostacyclin analogue enhanced the implantation rate from 42 to 76% [relative risk 1.84, 95% confidence interval (CI) 1.38-2.43]. The rate of live pups also increased from 28 to 36% (relative risk 1.28, 95% CI 1.04-1.56). The weights of the pups and of the placentae of the two groups were comparable. CONCLUSION: Prostacyclin enhances the potentials of implantation and live birth of mouse embryos.

Prostacyclin enhances embryo hatching but not sperm motility.

BACKGROUND: Recently we discovered that the human oviduct synthesizes abundant prostacyclin (PGI(2)). Gene knock-out studies suggest that PGI(2) is essential to endometrial decidualization, but the effects of PGI(2) on sperm and embryos have not been reported. METHODS: The effects of PGI(2) on human sperm were analysed by a computer-assisted semen analysis system. The effects of PGI(2) on mouse embryos were examined based on the rates of complete hatching. The expression of PGI(2) receptor (IP) was evaluated by Western blot analysis and immunohistochemistry. The binding of PGI(2) to embryos was confirmed by radioligand binding assay. Finally, cAMP levels were assessed in PGI(2)-challenged embryos. RESULTS: Iloprost (a stable PGI(2) analogue) did not affect the motility or the overnight survivability of human sperm. Western blot analysis did not detect IP in the sperm plasma membrane. In contrast, the hatching of mouse embryos was enhanced by iloprost (ED(50) 6.7 nmol/l). Exposure to iloprost during 8-cell to morulae or morulae to early blastocyst stages was critical to enhanced hatching. This coincided with the developmental stage-specific expression of IP. Although iloprost bound to blastocysts, it did not significantly increase cAMP. CONCLUSION: PGI(2) enhanced the hatching of mouse embryos but not the motility of human sperm.