Prospects for improving cosmological parameter estimation with gravitational-wave standard sirens from Taiji.

Taiji, a space-based gravitational-wave observatory, consists of three satellites forming an equilateral triangle with arm length of 3×106 km, orbiting around the Sun. Taiji is able to observe the gravitational-wave standard siren events of massive black hole binary (MBHB) merger, which is helpful in probing the expansion of the universe. In this paper, we preliminarily forecast the capability of Taiji for improving cosmological parameter estimation with the gravitational-wave standard siren data. We simulate five-year standard siren data based on three fiducial cosmological models and three models of MBHB's formation and growth. It is found that the standard siren data from Taiji can effectively break the cosmological parameter degeneracies generated by the cosmic microwave background (CMB) anisotropies data, especially for dynamical dark energy models. The constraints on cosmological parameters are significantly improved by the data combination CMB + Taiji, compared to the CMB data alone. Compared to the current optical cosmological observations, Taiji can still provide help in improving the cosmological parameter estimation to some extent. In addition, we consider an ideal scenario to investigate the potential of Taiji on constraining cosmological parameters. We conclude that the standard sirens of MBHB from Taiji will become a powerful cosmological probe in the future.

Tris(8-Hydroxyquinoline)iron induces apoptotic cell death via oxidative stress and by activating death receptor signaling pathway in human head and neck carcinoma cells.

BACKGROUND: 8-Hydroxyquinoline derivatives have highly sensitive fluorescent chemosensors for metal ions, which are associated with anti-oxidant, anti-tumor and anti-HIV-1 properties. Head and neck squamous cell carcinoma (HNSCC) is associated with a high rate of mortality and novel anti-HNSCC drugs must be developed. Therefore, effective chemotherapy agents are required to address this public health issue. HYPOTHESIS/PURPOSE: The aim of this study was to investigate the inhibitory effect of tris(8-hydroxyquinoline)iron (Feq3) on the HNSCC and the underlying mechanism. STUDY DESIGN/METHODS: A novel 8-hydroxyquinoline derivative, Feq3, was synthesized. The cell viabilities were analyzed using MTT reagent. Apoptosis and the cell cycle distributions were determined by flow cytometer. Reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence, western blot, MitoSOX and CellROX stain assay were used to study the mechanism of Feq3. Feq3 combined with antioxidants NAC (N-acetylcysteine) and BSO (buthionine sulfoximine) measured the cell viability and intracellular ROS. RESULTS: Feq3 induced the death of HNSCC cells and caused them to exhibit the morphological features of apoptosis. Feq3 also induced apoptosis of SCC9 cells by cell cycle arrest during the G2/M phase and the induced arrest of SCC25 cells in the G0/G1 and G2/M phases, which was associated with decreased cyclin B1/cdc2 and cyclin D/cdk4 expressions. Feq3 increases reactive oxygen species (ROS) and reduces glutathione (GSH) levels, and responds to increased p53 and p21 expressions. Feq3 induced apoptosis by mitochondria-mediated Bax and cytochrome c up-expression and down-expression Bcl-2. Feq3 also up-regulated tBid, which interacts with the mitochondrial pathway and tumor necrosis factor-α (TNF-α)/TNF-Rs, FasL/Fas, and TNF-related apoptosis inducing ligand receptors (TRAIL-Rs)/TRAIL-dependent caspases apoptotic signaling pathway in HNSCC cells. However, Feq3 activates Fas but not FasL in SCC25 cells. Feq3 arrests the growth of HNSCC cells and is involved in the mitochondria- and death receptor (DR)-mediated caspases apoptotic pathway. CONCLUSION: This study is the first to suggest that apoptosis mediates the anti-HNSCC of Feq3. Feq3 has potential as a cancer therapeutic agent against HNSCC.

Vitamin D decreases the secretion of eotaxin and RANTES in nasal polyp fibroblasts derived from Taiwanese patients with chronic rhinosinusitis with nasal polyps.

Eosinophils are important inflammatory cells involved in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). Vitamin D and its derivatives, in addition to their classic role as regulators of electrolytes homeostasis, have modulatory effects in immunological and inflammatory responses. Such properties suggest that vitamin D might also play a role in inflammatory airway diseases such as CRSwNP. In this study, we investigated the effect of vitamin D derivatives (calcitriol and tacalcitol) on the secretion of eotaxin and Regulated on Activation, Normal T Cell Expressed and Secreted (RANTES), the two major eosinophil chemoattractants, in fibroblasts derived from the polyps of Taiwanese CRSwNP patients. Patients diagnosed with eosinophilic CRSwNP but without malignancies or asthma and undergoing elective endoscopic sinus surgery were recruited. Three primary fibroblast cultures were established using the polyp specimens obtained from these patients. The third to eighth passages of the fibroblasts were used for in vitro studies. Nasal polyp-derived fibroblasts were stimulated with IL-1ß (10 ng/mL) for 24 hours, followed by replacement with media alone or with calcitriol or tacalcitol (10 µM) and incubation for another 24 hours. After the treatments, the levels of secreted eotaxin and RANTES were evaluated by ELISA assays. The results showed that IL-1ß could substantially stimulate the secretion of eotaxin (p < 0.01) and RANTES (p < 0.01) in nasal polyp-derived fibroblasts. More importantly, this stimulatory effect was significantly suppressed by adding calcitriol (p ≤ 0.002 for eotaxin and p ≤ 0.008 for RANTES) or tacalcitol (p ≤ 0.009 for eotaxin and p ≤ 0.02 for RANTES). Therefore, the inhibitory effect of vitamin D derivatives on eotaxin and RANTES secretion might shed light not only on the disease mechanism, but also on the potential use of vitamin D in pharmacotherapy of Taiwanese patients with CRSwNP.

Seizure after local anesthesia for nasopharyngeal angiofibroma.

We report a young male patient who experienced seizure after local injection of 3 mL 2% lidocaine with epinephrine 1:200,000 around a recurrent nasal angiofibroma. After receiving 100% oxygen via mask and thiamylal sodium, the patient had no residual neurologic sequelae. Seizure immediately following the injection of local anesthetics in the nasal cavity is probably due to injection into venous or arterial circulation with retrograde flow to the brain circulation. Further imaging study or angiography should be done before head and neck surgeries, especially in such highly vascular neoplasm.

Treatment of laryngeal radionecrosis with hyperbaric oxygen therapy: a case report.

An 81-year-old male with early-stage laryngeal carcinoma had been treated with 60 Gy curative radiotherapy. He complained of a sore throat, foul odor in the mouth, progressive dyspnea, and fever 2 months after the completion of radiotherapy. Direct laryngoscopy revealed narrowing of the glottis with diffuse ulcerative necrotic tissue. Biopsies at multiple sites and pathology revealed intense coagulation necrosis with complete denudation of covering epithelium without any malignancy. Since laryngeal radionecrosis was suspected, the patient received hyperbaric oxygen (HBO) therapy 40 times for 1 hour of 100% O2 at 2 atm absolute pressure. His clinical symptoms gradually improved and repeated endolaryngeal biopsies were undertaken near the end of HBO therapy and again 6 months later. The patient's larynx healed completely with diffuse fibrosis and no malignant cells were found on pathology. Radionecrosis must be differentiated from cancer recurrence following curative radiotherapy for early laryngeal cancer. HBO therapy could be a useful treatment adjunct for laryngeal radionecrosis.