Xenopus: An alternative model system for identifying muco-active agents

The airway epithelium in human plays a central role as the first line of defense against environmental contaminants. Most respiratory diseases such as chronic obstructive pulmonary disease (COPD), asthma, and respiratory infections, disturb normal muco-ciliary functions by stimulating the hypersecretion of mucus. Several muco-active agents have been used to treat hypersecretion symptoms in patients. Current muco-active reagents control mucus secretion by modulating either airway inflammation, cholinergic parasympathetic nerve activities or by reducing the viscosity by cleaving crosslinking in mucin and digesting DNAs in mucus. However, none of the current medication regulates mucus secretion by directly targeting airway goblet cells. The major hurdle for screening potential muco-active agents that directly affect the goblet cells, is the unavailability of in vivo model systems suitable for high-throughput screening. In this study, we developed a high-throughput in vivo model system for identifying muco-active reagents using Xenopus laevis embryos. We tested mucus secretion under various conditions and developed a screening strategy to identify potential muco-regulators. Using this novel screening technique, we identified narasin as a potential muco-regulator. Narasin treatment of developing Xenopus embryos significantly reduced mucus secretion. Furthermore, the human lung epithelial cell line, Calu-3, responded similarly to narasin treatment, validating our technique for discovering muco-active reagent

Dynamic and static volatility interruptions : evidence from the Korean stock markets

We conducted a comprehensive analysis on the sequential introductions of dynamic and static volatility interruptions (VIs) in the Korean stock markets. The Korea Exchange introduced VIs to improve price formation, and to limit risk to investors from brief periods of abnormal volatility for individual stocks. We found that dynamic VI is effective in price stabilization and discovery, while the effect of static VI is limited. The static VI functions similarly to the pre-existing price-limit system; this accounts for its limited incremental benefit

GJA1 depletion causes ciliary defects by affecting Rab11 trafficking to the ciliary base

The gap junction complex functions as a transport channel across the membrane. Among gap junction subunits, gap junction protein ??1 (GJA1) is the most commonly expressed subunit. A recent study showed that GJA1 is necessary for the maintenance of motile cilia; however, the molecular mechanism and function of GJA1 in ciliogenesis remain unknown. Here, we examined the functions of GJA1 during ciliogenesis in human retinal pigment epithelium-1 and Xenopus laevis embryonic multiciliated-cells. GJA1 localizes to the motile ciliary axonemes or pericentriolar regions beneath the primary cilium. GJA1 depletion caused malformation of both the primary cilium and motile cilia. Further study revealed that GJA1 depletion affected several ciliary proteins such as BBS4, CP110, and Rab11 in the pericentriolar region and basal body. Interestingly, CP110 removal from the mother centriole was significantly reduced by GJA1 depletion. Importantly, Rab11, a key regulator during ciliogenesis, was immunoprecipitated with GJA1 and GJA1 knockdown caused the mislocalization of Rab11. These findings suggest that GJA1 regulates ciliog

Xenopus gpx3 Mediates Posterior Development by Regulating Cell Death during Embryogenesis

Glutathione peroxidase 3 (GPx3) belongs to the glutathione peroxidase family of selenoproteins and is a key antioxidant enzyme in multicellular organisms against oxidative damage. Downregulation of GPx3 affects tumor progression and metastasis and is associated with liver and heart disease. However, the physiological significance of GPx3 in vertebrate embryonic development remains poorly understood. The current study aimed to investigate the functional roles of gpx3 during embryogenesis. To this end, we determined gpx3's spatiotemporal expression using Xenopus laevis as a model organism. Using reverse transcription polymerase chain reaction (RT-PCR), we demonstrated the zygotic nature of this gene. Interestingly, the expression of gpx3 enhanced during the tailbud stage of development, and whole mount in situ hybridization (WISH) analysis revealed gpx3 localization in prospective tail region of developing embryo. gpx3 knockdown using antisense morpholino oligonucleotides (MOs) resulted in short post-anal tails, and these malformed tails were significantly rescued by glutathione peroxidase mimic ebselen. The gene expression analysis indicated that gpx3 knockdown significantly altered the expression of genes associated with Wnt, Notch, and bone morphogenetic protein (BMP) signaling pathways involved in tailbud development. Moreover, RNA sequencing identified that gpx3 plays a role in regulation of cell death in the developing embryo. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and phospho-histone 3 (PH3) staining confirmed the association of gpx3 knockdown with increased cell death and decreased cell proliferation in tail region of developing embryos, establishing the involvement of gpx3 in tailbud development by regulating the cell death. Furthermore, these findings are inter-related with increased reactive oxygen species (ROS) levels in gpx3 knockdown embryos, as measured by using a redox-sensitive fluorescent probe HyPer. Taken together, our results suggest that gpx3 plays a critical role in posterior embryonic development by regulating cell death and proliferation during vertebrate embryogenesis

Round Cell Variant of Myxoid Liposarcoma in a Japanese Macaque (Macaca fuscata)

A 5-year-old, female, Japanese Macaque (Macaca fuscata) was diagnosed with round cell variant of myxoid liposarcoma. At necropsy, multifocal to coalescing, reddish tan to white nodules, ranging from 0.5 to 1 cm in diameter, were noted throughout the omentum and retroperitoneum. Similar neoplastic nodules were also present in diaphragm, abdominal wall, and on hepatic capsule. Microscopically, neoplastic masses consisted of round to polyhedral cells, which had round, often eccentric nuclei and abundant eosinophilic granular and microvacuolated cytoplasm; Oil red O staining demonstrated large numbers of lipid droplets in the cytoplasm. Ultrastructurally, the cytoplasm of the tumor cells was packed with occasional lipid vacuoles and numerous enlarged mitochondria. Immunohistochemistry revealed tumor cells were positive for vimentin, while negative to cytokeratin, actin, and Factor VIII–related antigen. To the authors' knowledge, this is the first report of round-cell variant of myxoid liposarcoma in nonhuman primate.This study was supported through Brain Korea 21 Program for Veterinary Science

Once-Daily Gentamicin Administration for Community-Associated Methicillin Resistant Staphylococcus aureus in an in vitro Pharmacodynamic Model: Preliminary Reports for the Advantages for Optimizing Pharmacodynamic Index

∙The authors have no financial conflicts of interest. Purpose: Community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infections are increasing. Although gentamicin (GEN) is usually susceptible against CA-MRSA, GEN is rarely considered for treatment as monotherapy. We employed an in vitro pharmacodynamic model (IVPDM) to compare efficacies of GEN against CA-MRSA with two dosing regimens [thrice-daily (TD), once-daily (OD)]. Materials and Methods: Using two strains of CA-MRSA, we adopted IVPDM comprised of two-compartments with a surface-to-volume ratio of 5.34 cm-1. GEN regimens were simulated with human pharmacokinetic data of TD and OD. Experiments were performed over 48 hours in triplicate for each strain and dosing regimen. Results: MICs of GEN for YSSA1 and YSSA15 were 1 and 2 mg/L, respectively. In OD, indices of peak/MIC were> 8.6 at least, in contrast to < 6.4 in TD. A ≥ 3-log10 reduction in CFU/mL was demonstrated prior to 4 hours in TD and OD, and continued until 8 hours for both strains. However, reductions in the colon

Occult bacteremia in children with simple febrile seizure in the post-pneumococcal conjugate vaccine era

Purpose The authors aimed to investigate the utility of blood culture (BC) for children with simple febrile seizure (SFS) in the emergency department (ED) in the post-10/13-valent pneumococcal conjugate vaccine (PCV) era. Methods This study was performed at the ED of a tertiary care university-affiliated women and children’s hospital, and involved 3,237 previously healthy children aged 6-60 months who visited the ED with SFS from January 2013 through December 2017. The SFS was defined according to the International Classification of Diseases, 11th Revision codes related to seizure. The children were divided into 2 groups according to the vaccination rates of the period of their visit: the 70-PCV (70%, 2013-2014) and 97-PCV (97%, 2015-2017) groups. The primary outcome was the yield, defined as a true positivity of BC. In addition, we collected information on baseline characteristics, ED length of stay, inflammatory biomarkers, and ED outcomes. Results Of the 1,578 children with SFS who underwent BC, 1,357 belonged to the 97-PCV group. The median age of the study population was 22 months (interquartile range, 16.0-30.0), and 935 children (59.3%) were boys. Of the 41 children (2.6%) with positive BC results, 3 had the yield (0.2%): Staphylococcus aureus in 2 children and Streptococcus pneumoniae in the other. All 3 children belonged to the 97-PCV group. There were 38 contaminated BCs (2.4%; 95% confidence interval, 1.6%-3.2%). The 97-PCV group showed a shorter median ED length of stay (166.0 minutes [108.0-279.5] vs. 143.0 [109.5-209.5]; P = 0.010) and a lower rate of hospitalization (39.4% vs. 12.8%; P < 0.001). No differences between the 2 groups were found in the baseline characteristics and biomarkers. Conclusion This study suggests a low utility of BC in previously healthy children with SFS in emergency settings in the post-10/13-valent PCV era

Renal Toxicity Evaluation and Comparison Between Visipaque (Iodixanol) and Hexabrix (Ioxaglate) in Patients With Renal Insufficiency Undergoing Coronary Angiography The RECOVER Study: A Randomized Controlled Trial

ObjectivesThis study sought to compare the nephrotoxicity of iodixanol and ioxaglate in patients with renal impairment undergoing coronary angiography.BackgroundIodixanol, a nonionic, dimeric, iso-osmolar contrast medium (IOCM), may be less nephrotoxic than low-osmolar contrast media (LOCM) in high-risk patients.MethodsIn a prospective, randomized trial in 300 adults with creatinine clearance (CrCl) ≤60 ml/min, patients received either iodixanol or ioxaglate and underwent coronary angiography with or without percutaneous coronary intervention. The primary end point was the incidence of contrast-induced nephropathy (CIN) (an increase in serum creatinine [SCr] ≥25% or ≥0.5 mg/dl [≥44.2 μmol/l]). The incidence of CIN in patients with severe renal impairment at baseline (CrCl <30 ml/min) or diabetes and in those receiving large doses (≥140 ml) of contrast medium was also determined.ResultsThe incidence of CIN was significantly lower with iodixanol (7.9%) than with ioxaglate (17.0%; p = 0.021), corresponding to an odds ratio (OR) of CIN of 0.415 (95% confidence interval [CI] 0.194 to 0.889) for iodixanol. The incidence of CIN was also significantly lower with iodixanol in patients with severe renal impairment (p = 0.023) or concomitant diabetes (p = 0.041), or in patients given ≥140 ml of contrast media (p = 0.038). Multivariate analysis identified use of ioxaglate (OR 2.65, 95% CI 1.11 to 6.33, p = 0.028), baseline SCr, mg/dl (OR 2.0, 95% CI 1.04 to 3.85, p = 0.038), and left ventricular ejection fraction, % (OR 0.97, 95% CI 0.94 to 0.99, p = 0.019) as independent risk factors for CIN.ConclusionsThe IOCM iodixanol was significantly less nephrotoxic than ioxaglate, an ionic, dimeric LOCM. (The RECOVER Trial; http://clinicaltrials.gov; NCT00247325