Analysis of COVID-19 mRNA Vaccine-induced Mouth Ulcers Using the Japanese Adverse Drug Event Report Database

There are case reports of mouth ulcers caused by the coronavirus disease 2019 (COVID-19) messenger ribonucleic acid (mRNA) vaccine; however, the actual number and characteristics of cases are unknown. Therefore, we examined this issue using the Japanese Adverse Drug Event Report (JADER), a large Japanese database. We calculated the reported odds ratio (ROR) of drugs that may be specifically associated with mouth ulcers and assumed that a signal was present if the lower limit of the calculated ROR's 95% confidence interval (CI) was > 1. In addition, the time to symptom onset after administration of the COVID-19 mRNA and influenza HA vaccines was investigated. We found that the JADER database contained 4,661 mouth ulcer cases between April 2004 and March 2022. The COVID-19 mRNA vaccine was the eighth most common causative drug for mouth ulcers, with 204 reported cases. The ROR was 1.6 (95% CI, 1.4-1.9) and a signal was detected. There were 172 mouthulcer cases associated with the Pfizer-BioNTech's COVID-19 mRNA vaccine, 76.2% of which were female. The outcome was no unrecovered cases with the influenza HA vaccine, whereas the COVID-19 mRNA vaccine showed unrecovered cases (Pfizer-BioNTech: 12.2%, Moderna: 11.1%). The median time-to-onset of the mouth ulcers was two days for the COVID-19 mRNA vaccine and one day for the influenza HA vaccine, indicating that mouth ulcers caused by the COVID-19 mRNA vaccine were delayed adverse events. In this study, the COVID-19 mRNA vaccine was shown to cause mouth ulcers in a Japanese population.

Utility of the Berlin Initiative Study-1 equation for the prediction of serum vancomycin concentration in elderly patients aged 75 years and older

Accurate assessment of renal function is essential for determining serum vancomycin (VCM) concentration. Creatinine clearance (Ccr)-calculated using the Cockcroft and Gault (CG) equation-can be used to evaluate renal function for determining VCM dosage. However, Ccr-based evaluation may not be an accurate representation of the renal function in the elderly. Herein, we examine the effectiveness of estimated glomerular filtration rate (eGFR) calculated using the Berlin Initiative Study-1 (BIS1) equation, for predicting the serum VCM concentration. Herein, we retrospectively analyzed patients (aged ≥ 75 years) who had received VCM. Serum VCM concentration was predicted based on Ccr and eGFR. eGFR was calculated using the Japanese equation for eGFR (eGFR_JAP), Modification of Diet in Renal Disease (MDRD) equation (eGFR_MDRD), chronic kidney disease epidemiology collaboration (CKD-EPI) equation (eGFR_CKD-EPI), and BIS1 equation (eGFR_BIS1). The predicted serum VCM concentration was compared with the measured values. Prediction bias, accuracy, and precision were evaluated by calculating the mean prediction error (ME), mean absolute prediction error (MAE), and root mean squared prediction error (RMSE). Our results showed that the ME between the measured and the predicted values calculated using Ccr and each eGFR was the largest and smallest when calculated based on Ccr and eGFR_MDRD, respectively. MAE and RMSE were the largest and smallest when calculated based on Ccr and eGFR_BIS1, respectively. A significant difference was observed in the MAE associated with eGFR_JAP, eGFR_MDRD, and eGFR_CKD-EPI compared to that associated with eGFR_BIS1. In conclusion, our results suggest that the BIS1 equation might be useful for determining the VCM dosage in the elderly.

The role of marshall bundle epicardial connections in atrial tachycardias after atrial fibrillation ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial tachycardias (ATs) are often seen in the context of AF ablation.

Objectives

We evaluated the role of the Marshall bundle (MB) network in left atrial (LA) ATs using high-density high-spatial resolution 3D mapping.

Methods

199 post-AF ablation LA tachycardias were mapped in 140 consecutive patients (112 (80%) males, mean age: 61.8 years); 133 (66.8%) were macro-reentrant and 66 (33.2%) were scar-related re-entry. MB-dependent perimitral AT (PMAT) was diagnosed where the difference between the post pacing interval and the tachycardia cycle length (PPI-TCL) was <20ms in parts of the expected MB-dependent perimitral circuit (within the VOM, the ridge between the left pulmonary veins and LA appendage (LAA), the anterior LA and between 6- and 11-o’clock of the mitral annulus) and the PPI-TCL was >20ms in areas bypassed by the VOM (the distal coronary sinus (CS), the posterior LA and the mitral isthmus). MB-related re-entry was diagnosed by PPI-TCL <20ms at the left lateral ridge, posterior base of LAA, inferolateral LA or VOM ostium; and PPI-TCL >20ms in the septal annulus. Typically, in MB-dependent localized re-entry, the earliest activation was found along the MB-LA endocardial connection or MB-CS epicardial connection. 

Results

The MB network was found to participate in 60 (30.2%) re-entrant ATs, 31 PMATs and 29 localized re-entries. High-frequency multiphasic fragmented electrograms with long duration were often recorded endocardially or epicardially at the MB-LA or MB-CS connections. The amplitude and duration of these signals were 0.5 ± 0.79 mV and 65 ± 40 ms for MB-PMATs and 0.26 ± 0.28mV and 122 ± 67 ms for MB-localized re-entries. Unipolar EGMs at the site of endocardial-epicardial breakthrough had a rS pattern in all MB-related ATs. Of 60 MB-related ATs, 49 (81.6%) terminated with RF ablation, 44 (73.3%) at the MB-LA junction and 5 (8.3%) at the MB-CS junction, while 9 (15%) terminated after 2.5-5 cc of alcohol infusion inside the vein of Marshall (VOM). Of the 31 MB-related macroreentrant ATs, 17 (54.8%) terminated at the MB-LA junction, 5 (16.1%) at the MB-CS junction and 7 (22.6%) with alcohol infusion inside the VOM. Two macroreentries (6.5%) using the MB did not terminate with RF energy either endocardially at the MB-LA junction or epicardially at the MB-CS junction, and we were unable to identify or cannulate the VOM for ethanol infusion. Of the 29 localized re-entrant ATs using the MB, 27 (93.1%) terminated at the MB-LA junction, none terminated at the MB-CS junction and 2 (6.9%) terminated after alcohol infusion. After a mean follow up of 12 months, only 4 patients (6.7%) had AT recurrence.

Conclusions

MB re-entrant ATs accounted for up to 29% of the left ATs after AF ablation. Ablation of the MB-LA or CS-MB connections or alcohol infusion inside the VOM is required to treat these arrhythmias. Abstract Figure.

The Spectrum of Idiopathic Ventricular Fibrillation and J-Wave Syndromes: Novel Mapping Insights

Idiopathic ventricular fibrillation and J-wave syndromes are causes of sudden cardiac death (SCD) without any identified structural cardiac disease after extensive investigations. Recent data show that high-density electrophysiological mapping may ultimately offer diagnoses of subclinical diseases in most patients including those termed "unexplained" SCD. Three major conditions can underlie the occurrence of SCD: (1) localized depolarization abnormalities (due to microstructural myocardial alteration), (2) Purkinje abnormalities manifesting as triggering ectopy and inducible reentry; or (3) repolarization heterogeneities. Each condition may result from a spectrum of pathophysiologic processes with implications for individual therapy.

5201Intra-cardiac thrombus in patients undergoing ventricular tachycardia ablation. a computed tomographic scan study

Background

Embolic event is one of the complications of VT ablation. This may be due to the presence of intra-cardiac thrombus before ablation. However, there is no clear consensus on how to rule out thrombus before the procedure.

Objective

We sought to examine the prevalence and risk factors of intra-cardiac thrombus with cardiac computed tomographic (CT) scan in patients undergoing scar-related VT ablation.

Methods

In absence of contra-indication, all patients undergoing scar-related VT ablation at our institution underwent contrast-enhanced cardiac CT within one week before ablation. 324 consecutive patients (292 male, 59±16 yo) have been included in this study. The etiology was ischemic cardiomyopathy (CMP) (n=191), arrhythmogenic right ventricular CMP (ARVC) (n=37), congenital CMP (n=11) or other CMP (n=85). LVEF was <40% in 154 patients (48%).

Results

Intra-cardiac thrombus was diagnosed in 29 (9%) patients: in the left atrium (n=8), in the right atrium (n=1), in the left ventricle (n=15), in the right ventricle (n=3), in right and left atrium (n=1), and in left atrium and right ventricle (n=1). Moreover in 2, a bilateral pulmonary embolism was identified. The population with thrombus was older (65±12 vs 58±16 years, p=0,005), with more permanent atrial fibrillation (AF) (28% vs 8%; p=0.005). Patients with left ventricular (LV) aneurysm were at higher risk of thrombus 50% vs 3% (p<0.001). The average CHADSVASC score was similar for both groups (2,5 vs 2,1; p=0.179). After matching for age and sex, only ischemic CMP and LV aneurysm were risk factors for thrombus. Because of arrhythmic storm, ablation was performed by epicardial approach only, in 5 patients with intra-ventricular thrombus and by retroaortic approach only, in 2 patients with LAA thrombus. No embolic event occurred during these procedures.

Conclusion

CT scans help eliminating intra-cardiac thrombus before VT ablation procedure. A high proportion of thrombus (9%) was identified. Whereas LV thrombus should systematically be ruled out before scar related VT ablation, in patients with AF, a LAA thrombus should also be eliminated as well as RV thrombus in patients with ARVC.

Acknowledgement/Funding

ANR-10-IAHU-04

Balance of Emission and Dynamical Controls on Ozone During the Korea-United States Air Quality Campaign From Multiconstituent Satellite Data Assimilation

Global multiconstituent concentration and emission fields obtained from the assimilation of the satellite retrievals of ozone, CO, NO2, HNO3, and SO2 from the Ozone Monitoring Instrument (OMI), Global Ozone Monitoring Experiment 2, Measurements of Pollution in the Troposphere, Microwave Limb Sounder, and Atmospheric Infrared Sounder (AIRS)/OMI are used to understand the processes controlling air pollution during the Korea-United States Air Quality (KORUS-AQ) campaign. Estimated emissions in South Korea were 0.42 Tg N for NO x and 1.1 Tg CO for CO, which were 40% and 83% higher, respectively, than the a priori bottom-up inventories, and increased mean ozone concentration by up to 7.5 ± 1.6 ppbv. The observed boundary layer ozone exceeded 90 ppbv over Seoul under stagnant phases, whereas it was approximately 60 ppbv during dynamical conditions given equivalent emissions. Chemical reanalysis showed that mean ozone concentration was persistently higher over Seoul (75.10 ± 7.6 ppbv) than the broader KORUS-AQ domain (70.5 ± 9.2 ppbv) at 700 hPa. Large bias reductions (>75%) in the free tropospheric OH show that multiple-species assimilation is critical for balanced tropospheric chemistry analysis and emissions. The assimilation performance was dependent on the particular phase. While the evaluation of data assimilation fields shows an improved agreement with aircraft measurements in ozone (to less than 5 ppbv biases), CO, NO2, SO2, PAN, and OH profiles, lower tropospheric ozone analysis error was largest at stagnant conditions, whereas the model errors were mostly removed by data assimilation under dynamic weather conditions. Assimilation of new AIRS/OMI ozone profiles allowed for additional error reductions, especially under dynamic weather conditions. Our results show the important balance of dynamics and emissions both on pollution and the chemical assimilation system performance.

Universal geometric frustration in pyrochlores

Materials with the pyrochlore/fluorite structure have diverse technological applications, from magnetism to nuclear waste disposal. Here we report the observation of structural instability present in the pyrochlores A₂Zr₂O₆Oʹ (A = Pr, La) and Yb₂Ti₂O₆Oʹ, that exists despite ideal stoichiometry, ideal cation-ordering, the absence of lone pair effects, and a lack of magnetic order. Though these materials appear to have good long-range order, local structure probes find displacements, of the order of 0.01 nm, within the pyrochlore framework. The pattern of displacements of the A₂Oʹ sublattice mimics the entropically-driven fluxional motions characteristic of and well-known in the silica mineral β-cristobalite. The universality of such displacements within the pyrochlore structure adds to the known structural diversity and explains the extreme sensitivity to composition found in quantum spin ices and the lack of ferroelectric behavior in pyrochlores.

The family of pyrochlore complex oxides includes many materials of fundamental or practical interest, such as spin ices and dielectrics. Trump et al. show that flexibility of the pyrochlores’ structure leads to local displacements that explain some of their unusual physical properties.

Classical Spin Nematic Transition in LiGa_{0.95}In_{0.05}Cr_{4}O_{8}

We present the results of a combined ^{7}Li-NMR and diffraction study on LiGa_{0.95}In_{0.05}Cr_{4}O_{8}, a member of the LiGa_{1-x}In_{x}Cr_{4}O_{8} "breathing" pyrochlore family. Via specific heat and NMR measurements, we find that the complex sequence of first-order transitions observed for LiGaCr_{4}O_{8} is replaced by a single second-order transition at T_{f}=11  K. Neutron and x-ray diffraction rule out both structural symmetry lowering and magnetic long-range order as the origin of this transition. Instead, reverse Monte Carlo fitting of the magnetic diffuse scattering indicates that the low-temperature phase may be described as a collinear spin nematic state, characterized by a quadrupolar order parameter. This state also shows signs of short-range order between collinear spin arrangements on tetrahedra, revealed by mapping the reverse Monte Carlo spin configurations onto a three-state color model.

Low-intensity pulsed ultrasound (LIPUS) treatment of cultured chondrocytes stimulates production of CCN family protein 2 (CCN2), a protein involved in the regeneration of articular cartilage: mechanism underlying this stimulation

OBJECTIVE

CCN family protein 2/connective tissue growth factor (CCN2/CTGF) promotes cartilage regeneration in experimental osteoarthritis (OA) models. However, CCN2 production is very low in articular cartilage. The aim of this study was to investigate whether or not CCN2 was promoted by cultured chondrocytes treated with low-intensity pulsed ultrasound (LIPUS) and to clarify its mechanism.

METHODS

Human chondrocytic cell line (HCS)-2/8, rat primary epiphyseal and articular cartilage cells, and Ccn2-deficient chondrocytes that impaired chondrocyte differentiation, were treated with LIPUS for 20 min at 3.0 MHz frequency and 60 mW/cm² power. Expressions of chondrocyte differentiation marker mRNAs were examined by real-time PCR (RT-PCR) analysis from HCS-2/8 cells and Ccn2-deficient chondrocytes at 30 min and 1 h after LIPUS treatment, respectively. CCN2 production was examined by Western blotting after 5 h of LIPUS treatment. Moreover, Ca²⁺ influx was measured by using a Fluo-4 probe.

RESULTS

The gene expression of chondrocyte differentiation markers and CCN2 production were increased in cultured chondrocytes treated with LIPUS. In addition, Ca²⁺ influx and phosphorylation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK)1/2 were increased by LIPUS treatment, and the stability of TRPV4 and BK_ca channel mRNAs was decreased by siRNA against CCN2. Consistent with those findings, the LIPUS-induced the gene expressions of type II collagen (COL2a1) and Aggrecan (ACAN) observed in wild-type cells were not observed in the Ccn2-deficient chondrocytes.

CONCLUSION

These data indicate that chondrocyte differentiation represented by CCN2 production was mediated via MAPK pathways activated by LIPUS-stimulated Ca²⁺ influx, which in turn was supported by the induced CCN2 molecules in articular chondrocytes.

Real space imaging of spin polarons in Zn-doped SrCu(2)(BO(3))(2)

We report on the real space profile of spin polarons in the quasi-two-dimensional frustrated dimer spin system SrCu(2)(BO(3))(2) doped with 0.16% of Zn. The (11)B nuclear magnetic resonance spectrum exhibits 15 additional boron sites near nonmagnetic Zn impurities. With the help of exact diagonalizations of finite clusters, we have deduced from the boron spectrum, the distribution of local magnetizations at the Cu sites with fine spatial resolution, providing direct evidence for an extended spin polaron. The results are confronted with those of other experiments performed on doped and undoped samples of SrCu(2)(BO(3))(2).

Identification of transactivation-responsive DNA-binding protein 43 (TARDBP43; TDP-43) as a novel factor for TNF-α expression upon lipopolysaccharide stimulation in human monocytes

BACKGROUND AND OBJECTIVE

Tumor necrosis factor alpha (TNF-α) is a major cytokine implicated in various inflammatory diseases. The nature of the nuclear factors associated with human TNF-α gene regulation is not well elucidated. We previously identified a novel region located from -550 to -487 in human TNF-α promoter that did not contain the reported binding sites for nuclear factor kappa B (NF-κB) but showed lipopolysaccharide (LPS)-induced transcriptional activity. The purpose of this study is to identify novel factors that bind to the promoter region and regulate TNF-α expression.

MATERIAL AND METHODS

To identify DNA-binding proteins that bound to the target region of TNF-α promoter, a cDNA library from LPS-stimulated human monocytic cell line THP-1 was screened using a yeast one-hybrid system. Cellular localizations of the DNA-binding protein in the cells were examined by subcellular immunocytochemistry. Nuclear amounts of the protein in LPS-stimulated THP-1 cells were identified by western blot analysis. Expression of mRNA of the protein in the cells was quantified by real-time polymerase chain reaction. Electrophoretic mobility shift assays were performed to confirm the DNA-binding profile. Overexpression of the protein and knockdown of the gene were also performed to investigate the role for TNF-α expression.

RESULTS

Several candidates were identified from the cDNA library and transactivation-responsive DNA-binding protein 43 (TARDBP43; TDP-43) was focused on. Western blot analysis revealed that nuclear TDP-43 protein was increased in the LPS-stimulated THP-1 cells. Expression of TDP-43 mRNA was already enhanced before TNF-α induction by LPS. Electrophoretic mobility shift assay analysis showed that nuclear extracts obtained by overexpressing FLAG-tagged TDP-43 bound to the -550 to -487 TNF-α promoter fragments. Overexpression of TDP-43 in THP-1 cells resulted in an increase of TNF-α expression. Knockdown of TDP-43 in THP-1 cells downregulated TNF-α expression.

CONCLUSION

We identified TDP-43 as one of the novel TNF-α factors and found that it bound to the LPS-responsive element in the TNF-α promoter to increase TNF-α expression.

Using Bayesian optimization method and FLEXPART tracer model to evaluate CO emission in East China in springtime

Carbon monoxide (CO) is of great interest as a restriction factor for pollutants related to incomplete combustions. This study attempted to evaluate CO emission in East China using the analytical Bayesian inverse method and observations at Mount Hua in springtime. The mixing ratio of CO at the receptor was calculated using 5-day source-receptor relationship (SRR) simulated by a Lagrangian Particle Dispersion Model (FLEXPART) and CO emission flux. The stability of the inversion solution was evaluated on the basis of repeated random sampling simulations. The inversion results demonstrated that there were two city cluster regions (the Beijing-Tianjin-Hebei region and the low reaches of the Yangtze River Delta) where the difference between a priori (Intercontinental Chemical Transport Experiment-Phase B, INTEX-B) and a posteriori was statistically significant and the a priori might underestimate the CO emission flux by 37 %. A correction factor (a posteriori/a priori) of 1.26 was suggested for CO emission in China in spring. The spatial distribution and magnitude of the CO emission flux were comparable to the latest regional emission inventory in Asia (REAS2.0). Nevertheless, further evaluation is still necessary in view of the larger uncertainties for both the analytical inversion and the bottom-up statistical approaches.

Report on the 7(th) international workshop on the CCN family of genes : October 16-19, 2013-Nice, France

In this report, chairs of the 7th International Workshop on the CCN family of Genes, review the progress made in understanding the biological functions of CCN proteins (CCN1, CCN2, CCN3, CCN4, CCN5 and CCN6) with a particular focus on their implications in various pathological conditions, including cancer, fibrosis, diabetes, and cardiovascular diseases.

Incomplete devil's staircase in the magnetization curve of SrCu2(BO3)2

We report on NMR and torque measurements on the frustrated quasi-two-dimensional spin-dimer system SrCu(2)(BO(3))(2) in magnetic fields up to 34 T that reveal a sequence of magnetization plateaus at 1/8, 2/15, 1/6, and 1/4 of the saturation and two incommensurate phases below and above the 1/6 plateau. The magnetic structures determined by NMR involve a stripe order of triplets in all plateaus, suggesting that the incommensurate phases originate from proliferation of domain walls. We propose that the magnetization process of SrCu(2)(BO(3))(2) is best described as an incomplete devil's staircase.

Tetrahedral magnetic order and the metal-insulator transition in the pyrochlore lattice of Cd2Os2O7

Cd2Os2O7 shows a peculiar metal-insulator transition at 227 K with magnetic ordering in a frustrated pyrochlore lattice, but its magnetic structure in the ordered state and the transition origin are yet uncovered. We observed a commensurate magnetic peak by resonant x-ray scattering in a high-quality single crystal. X-ray diffraction and Raman scattering experiments confirmed that the transition is not accompanied with any spatial symmetry breaking. We propose a noncollinear all-in-all-out spin arrangement on the tetrahedral network made of Os atoms. Based on this we suggest that the transition is not caused by the Slater mechanism as believed earlier but by an alternative mechanism related to the formation of the specific tetrahedral magnetic order on the pyrochlore lattice in the presence of strong spin-orbit interactions.

Magnetic Coulomb fields of monopoles in spin ice and their signatures in the internal field distribution

Fractionalization-the breaking up of an apparently indivisible microscopic degree of freedom-is one of the most counterintuitive phenomena in many-body physics. Here we study its most fundamental manifestation in spin ice, the only known fractionalized magnetic compound in 3D: we directly visualize the 1/r(2) magnetic Coulomb field of monopoles that emerge as the atomic magnetic dipoles fractionalize. We analyze the internal magnetic field distribution, relevant for local experimental probes. In particular, we present new zero-field NMR measurements that exhibit excellent agreement with the calculated line shapes, noting that this experimental technique can in principle measure directly the monopole density in spin ice. The distribution of field strengths is captured by a simple analytical form that exhibits a low density of low-field sites-in apparent disagreement with reported muon spin rotation results. Counterintuitively, the density of low-field locations decreases as the local ferromagnetic correlations imposed by the ice rules weaken.

Spontaneous formation of a superconducting and antiferromagnetic hybrid state in SrFe2As2 under high pressure

We report a novel superconducting (SC) and antiferromagnetic (AF) hybrid state in SrFe(2)As(2) revealed by (75)As nuclear magnetic resonance (NMR) experiments on a single crystal under highly hydrostatic pressure up to 7 GPa. The NMR spectra at 5.4 GPa indicate simultaneous development of the SC and AF orders below 30 K. The nuclear spin-lattice relaxation rate in the SC domains shows a substantial residual density of states, suggesting proximity effects due to the spontaneous formation of a nanoscale SC-AF hybrid structure. This entangled behavior is a remarkable example of a self-organized heterogeneous structure in a clean system.

Nicotine-induced CCN2: from Smoking to Periodontal Fibrosis

Since fibrosis is observed in smokers’ gingiva, it was hypothesized that fibrosis was caused by nicotine in the periodontium. Therefore, in this study, we investigated the effects of nicotine on the induction of a profibrotic molecule, connective tissue growth factor (CCN2/CTGF), in human gingival fibroblasts (HGFs) and periodontal ligament (PDL) cells. With 1 μg/mL nicotine, vacuolization and attenuated proliferation were observed. Interestingly, 1 μg/mL nicotine increased the production of CCN2/CTGF protein in both cells without increasing mRNA expression. Furthermore, type I collagen mRNA and protein were also increased and were significantly blocked by a CCN2/CTGF neutralizing antibody. This is the first report to describe a relationship between nicotine and CCN2/CTGF in periodontal tissue cells. Analysis of our data also indicated that nicotine was cytotoxic, while it increased CCN2/CTGF and, eventually, type I collagen production. These findings suggest that periodontal fibrosis can be promoted by nicotine from smoking via effects on CCN2/CTGF.

Phase diagram and spin dynamics in volborthite with a distorted kagome lattice

We report a (51)V-NMR study on a high-quality powder sample of volborthite Cu3V2O7(OH)2 . 2H2O, a spin-1/2 Heisenberg antiferromagnet on a distorted kagome lattice formed by isosceles triangles. In the magnetic fields below 4.5 T, a sharp peak in the nuclear spin-lattice relaxation rate 1/T(1) accompanied with line broadening revealed a magnetic transition near 1 K. The low temperature phase shows anomalies such as a Lorentzian line shape, a 1/T(1) proportional, variantT behavior indicating dense low-energy excitations, and a large spin-echo decay rate 1/T(2) pointing to unusually slow fluctuations. Another magnetic phase appears above 4.5 T with less anomalous spectral shape and dynamics.

CTGF and apoptosis in mouse osteocytes induced by tooth movement

It is known that experimental tooth movement stimulates the gene expression of connective tissue growth factor (CTGF) and induces apoptosis in osteocytes in rats. We hypothesized that there is a relationship between CTGF expression and the induction of apoptosis in osteocytes, to play a significant role in triggering bone remodeling during experimental tooth movement. In this study, CTGF mRNA expression was detected at 2 hours in osteocytes on the pressure side, followed by apoptosis at 6 hours after tooth movement in mice. The number of empty lacunae significantly increased on day 1 after mechanical stimulation. Thereafter, the number of osteoclasts significantly increased on the pressure side of the alveolar bone on day 3. Tooth movement increased rapidly on day 10. These findings suggest that CTGF expression, followed by apoptosis in osteocytes in response to mechanical stimulation, might play a significant role in triggering bone remodeling during tooth movement.

Local lattice distortion in the giant negative thermal expansion material Mn3Cu1-xGexN

Giant negative thermal expansion is achieved in antiperovskite manganese nitrides when the sharp volume change associated with magnetic ordering is broadened by substitution. In this Letter, we address the unique role of the ''magic" element, Ge, for such broadening in Mn3Cu1-xGexN. We present evidence for a local lattice distortion well described by the low-temperature tetragonal (T4) structure of Mn3GeN for a range of x, where the overall structure remains cubic. This structural instability shows a strong correlation with the broadness of the growth of the ordered magnetic moment and, hence, is considered to trigger the broadening of the volume change.

NMR evidence for the persistence of a spin superlattice beyond the 1/8 magnetization plateau in SrCu2(BO3)_{2}

We present 11B NMR studies of the 2D frustrated dimer spin system SrCu2(BO3)_{2} in the field range 27-31 T covering the upper phase boundary of the 1/8 magnetization plateau, identified at 28.4 T. Our data provide a clear evidence that above 28.4 T the spin superlattice of the 1/8 plateau is modified but does not melt even though the magnetization increases. Although this is precisely what is expected for a supersolid phase, the microscopic nature of this new phase is much more complex. We discuss the field-temperature phase diagram on the basis of our NMR data.

CCN family 2/connective tissue growth factor (CCN2/CTGF) stimulates proliferation and differentiation of auricular chondrocytes

OBJECTIVES

CCN family 2/connective tissue growth factor (CCN2/CTGF) is an atypical growth factor for growth plate chondrocytes. It plays an important role in their proliferation and differentiation in vitro, but does not stimulate hypertrophy or calcification of articular chondrocytes. We herein report for the first time that CCN2/CTGF promotes growth and differentiation of auricular chondrocytes and maintains their molecular phenotype in vitro and in vivo.

METHODS

Auricular chondrocytes were isolated from rabbit auricular cartilage by trypsin-collagenase treatment, and treated with human recombinant CCN2/CTGF or infected with adenovirus harboring the ccn2/ctgf gene. Cell proliferation was measured by [(3)H] thymidine incorporation and MTS assay, and changes in gene expression of auricular chondrocyte markers were monitored by real-time polymerase chain reaction, Northern hybridization, and histological analysis. For in vivo studies, auricular chondrocytes were cultured as pellets and implanted subcutaneously after treatment of recombinant human CCN2/CTGF. Ectopically formed cartilage was subjected to histological analysis. Cell death was monitored by in situ TUNEL analysis.

RESULTS

CCN2/CTGF stimulated proliferation, differentiation and synthesis of elastin and proteoglycans of rabbit primary auricular chondrocytes in a dose-dependent manner. CCN2/CTGF caused a 2.5-fold increase in the expression of elastin in comparison to the control, resulting in enhanced deposition of elastin fibers in a monolayer culture of auricular chondrocytes. Mineralization was not induced; in contrast, CCN2/CTGF stimulated expression of matrix gla protein which is known to impair mineralization. Furthermore, pretreatment of pellets of auricular chondrocytes with CCN2/CTGF and subcutaneous implantation significantly enhanced the growth of ectopic auricular cartilage pieces expressing phenotypic markers of auricular chondrocytes including type II and X collagen. Notably, chondrocyte apoptosis was impaired by CCN2/CTGF.

CONCLUSIONS

These findings show that CCN2/CTGF may be a suitable agent for promoting differentiation and growth of auricular chondrocytes, while preventing mineralization and apoptosis, and suggests that CCN2/CTGF may be useful for the repair or reconstruction of elastic cartilage.

NMR observation of rattling phonons in the pyrochlore superconductor KOs2O6

We report nuclear magnetic resonance studies on the beta-pyrochlore oxide superconductor KOs2O6. The nuclear relaxation at the K sites is entirely caused by fluctuations of the electric field gradient, which we ascribe to highly anharmonic low frequency oscillation (rattling) of K ions. A phenomenological analysis shows a crossover from overdamped to underdamped behavior of the rattling phonons with decreasing temperature and its sudden sharpening below the superconducting transition temperature T(c). Suppression of the Hebel-Slichter peak in the relaxation rate at the O sites below T(c) also indicates strong electron-phonon coupling.