274 research outputs found
Proximity to Fermi-surface topological change in superconducting LaO0.54F0.46BiS2
The electronic structure of nearly optimally-doped novel superconductor
LaOFBiS ( = 0.46) was investigated using
angle-resolved photoemission spectroscopy (ARPES). We clearly observed band
dispersions from 2 to 6 eV binding energy and near the Fermi level (), which are well reproduced by first principles calculations when
the spin-orbit coupling is taken into account. The ARPES intensity map near
shows a square-like distribution around the (Z) point
in addition to electronlike Fermi surface (FS) sheets around the X(R) point,
indicating that FS of LaOFBiS is in close proximity to
the theoretically-predicted topological change.Comment: 6 pages, 3 figures, + supplemental materia
SHED Repair Critical-Size Calvarial Defects in Mice
OBJECTIVE Stem cells from human exfoliated deciduous teeth (SHED) are a population of highly proliferative postnatal stem cells capable of differentiating into odontoblasts, adipocytes, neural cells, and osteo-inductive cells. To examine whether SHED-mediated bone regeneration can be utilized for therapeutic purposes, we used SHED to repair critical-size calvarial defects in immuno-compromised mice. MATERIALS AND METHODS We generated calvarial defects and transplanted SHED with hydroxyapatite/ tricalcium phosphate as a carrier into the defect areas. RESULTS SHED were able to repair the defects with substantial bone formation. Interestingly, SHED-mediated osteogenesis failed to recruit hematopoietic marrow elements that are commonly seen in bone marrow mesenchymal stem cell-generated bone. Furthermore, SHED were found to co-express mesenchymal stem cell marker, CC9/MUC18/CD146, with an array of growth factor receptors such as transforming growth factor β receptor I and II, fibroblast growth factor receptor I and III, and vascular endothelial growth factor receptor I, implying their comprehensive differentiation potential. CONCLUSIONS Our data indicate that SHED, derived from neural crest cells, may select unique mechanisms to exert osteogenesis. SHED might be a suitable resource for orofacial bone regeneration
A phase 3 randomized controlled trial of a COVID-19 recombinant vaccine S-268019-b versus ChAdOx1 nCoV-19 in Japanese adults
We assessed S-268019-b, a recombinant spike protein vaccine with a squalene-based adjuvant, for superiority in its immunogenicity over ChAdOx1 nCoV-19 vaccine among adults in Japan. In this multicenter, randomized, observer-blinded, phase 3 study, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–naïve participants (aged ≥ 18 years, without prior infection or vaccination against SARS-CoV-2) were randomized (1:1) to receive either S-268019-b or ChAdOx1 nCoV-19 as two intramuscular injections given 28 days apart. Participants who provided consent for a booster administration received S-268019-b at Day 211. The primary endpoint was SARS-CoV-2 neutralizing antibody (NAb) titer on Day 57; the key secondary endpoint was the seroconversion rate for SARS-CoV-2 NAb titer on Day 57. Other endpoints included anti–SARS-CoV-2 S-protein immunoglobulin (Ig)G antibody titer and safety. The demographic and baseline characteristics were generally comparable between S-268019-b (n = 611) and ChAdOx1 nCoV-19 (n = 610) groups. S-268019-b showed superior immunogenicity over ChAdOx1 nCoV-19, based on their geometric mean titers (GMTs) and GMT ratios of SARS-CoV-2 NAb on Day 57 by cytopathic effect assay (GMT [95% confidence interval {CI}] 19.92 [18.68, 21.23] versus 3.63 [3.41, 3.87]; GMT ratio [95% CI] 5.48 [5.01, 6.00], respectively; two-sided p-values < 0.0001). Additionally, NAb measured using a cell viability assay also showed similar results (GMT [95% CI] 183.25 [168.04, 199.84] versus 24.79 [22.77, 27.00]; GMT ratio [95% CI] 7.39 [6.55, 8.35] for S-268019-b versus ChAdOx1 nCoV-19, respectively; p < 0.0001). The GMT of anti–SARS-CoV-2 S-protein IgG antibody was 370.05 for S-268019-b versus 77.92 for ChAdOx1 nCoV-19 on Day 57 (GMT ratio [95% CI] 4.75 [4.34, 5.20]). Notably, immune responses were durable through the end of the study. S-268019-b elicited T-helper 1 skewed T-cell response, comparable to that of ChAdOx1 nCoV-19. After the first dose, the incidence of solicited systemic treatment-related adverse events (TRAEs) was higher in the ChAdOx1 nCoV-19 group, but after the second dose, the incidence was higher in the S-268019-b group. Headache, fatigue, and myalgia were the most commonly reported solicited systemic TRAEs, while pain at the injection site was the most frequently reported solicited local TRAE following both doses in both groups. No serious treatment-related adverse serious TRAEs events were reported in the two groups. S-268019-b was more immunogenic than ChAdOx1 nCoV-19 vaccine and was well tolerated (jRCT2051210151)
Five Amino Acid Residues Responsible for the High Stability of Hydrogenobacter thermophilus Cytochrome c552
Five amino acid residues responsible for extreme stability have been identified in cytochrome c552 (HT c552) from a thermophilic bacterium, Hydrogenobacter thermophilus. The five residues, which are spatially distributed in three regions of HT c552, were replaced with the corresponding residues in the homologous but less stable cytochrome c551 (PA c551) from Pseudomonas aeruginosa. The quintuple HT c552 variant (A7F/M13V/Y34F/Y43E/I78V) showed the same stability against guanidine hydrochloride denaturation as that of PA c551, suggesting that the five residues in HT c552 necessarily and sufficiently contribute to the overall stability. In the three HT c552 variants carrying mutations in each of the three regions, the Y34F/Y43E mutations resulted in the greatest destabilization, by –13.3 kJ mol–1, followed by A7F/M13V (–3.3 kJ mol–1) and then I78V (–1.5 kJ mol–1). The order of destabilization in HT c552 was the same as that of stabilization in PA c551 with reverse mutations such as F34Y/E43Y, F7A/V13M, and V78I (13.4, 10.3, and 0.3 kJ mol–1, respectively). The results of guanidine hydrochloride denaturation were consistent with those of thermal denaturation for the same variants. The present study established a method for reciprocal mutation analysis. The effects of side-chain contacts were experimentally evaluated by swapping the residues between the two homologous proteins that differ in stability. A comparative study of the two proteins was a useful tool for assessing the amino acid contribution to the overall stability.This work was supported in part by grants from Hiroshima University, the Noda Institute for Scientific Research, and the Japanese Ministry of Education, Science and Culture (grants-in-aid for Scientific Research on Priority Areas)
The impact of molecular profile on the lymphatic spread pattern in stage III colon cancer
The anatomical spread of lymph node (LN) metastasis is of practical importance in the surgical management of colon cancer (CC). We examined the effect of KRAS, BRAF, and microsatellite instability (MSI) on LN count and anatomical spread pattern in stage III CC. We determined KRAS, BRAF, and MSI status from stage III CC patients. Biomarker status was correlated with LN count and anatomical spread pattern, which was classified as sequential or skipped. Relapse-free survival (RFS) was estimated using Kaplan-Meier method, and correlations were assessed using log-rank and Cox regression analyses. We analyzed 369 stage III CC patients. The proportion of KRAS mutant (mt), BRAF mt, and MSI-high (H) were 44.2% (163/344), 6.8% (25/344), and 6.8% (25/344), respectively. The mean number of metastatic LN was higher in microsatellite-stable (MSS) compared with MSI patients (3.5 vs. 2.7, P = .0406), although no differences were observed in accordance with KRAS or BRAF status. Interestingly, patients with BRAF mt and MSI-H were less likely to harbor skipped metastatic LN (9.3% vs 20% and 4% vs 10.5% compared with BRAF wild-type (wt) and MSS, respectively), but KRAS status did not predict anatomical spread pattern. Patients with KRAS wt and MSI-H showed superior RFS compared with KRAS mt and MSS patients, respectively, whereas BRAF status did not affect RFS. Differences exist in the anatomical pattern of invaded LN in accordance with the molecular status of stage III CC. Patients with MSI-H CC have less invaded and skipped LN, suggesting that a tailored surgical approach is possible
A SARS-CoV-2 recombinant spike protein vaccine (S-268019-b) for COVID-19 prevention during the Omicron-dominant period: a phase 3, randomised, placebo-controlled clinical trial
Clinical trials of new vaccines based on existing variants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are often impacted by the emergence of new virus variants. We evaluated the efficacy, immunogenicity, and safety of S-268019-b, a recombinant spike protein subunit vaccine based on the ancestral strain, for preventing symptomatic coronavirus disease 2019 (COVID-19) during the Omicron (BA.2)-dominant period in Vietnam. In this multicentre, phase 3, randomised (2:1), observer-blind, placebo-controlled crossover study, participants received 2 intramuscular doses (28 days apart) of either 10 µg of S-268019-b (Recombinant S-protein vaccine) or placebo. The primary endpoint was incidence of laboratory-confirmed symptomatic COVID-19 before crossover, with onset within 14 days following the second dose, in participants who were seronegative and reverse transcription polymerase chain reaction (RT-PCR)-negative at baseline. The secondary endpoints included immunogenicity and safety. In total, 8,594 participants were randomised (S-268019-b [n = 5,727]; placebo [n = 2,867]). Vaccine efficacy versus placebo was 39·1 % (95 % confidence interval [CI]:26·6–49·5; one-sided P = 0·0723). The incidence rate (95 % CI) of symptomatic COVID-19 was 776·41/1,000 person-years (682·04–880·19) in the S-268019-b group and 1272·87/1,000 person-years (1101·32–1463·57) in the placebo group. The geometric mean titres (95 % CI) of the SARS-CoV-2 neutralising antibody increased on Day 57 versus baseline with S-268019-b (34·66 [27·04–44·41] versus 2·50 (non-estimable) but not with placebo. There were no safety concerns regarding S-268019-b. S-268019-b did not demonstrate the targeted efficacy threshold against symptomatic COVID-19; however, findings were comparable with other prophylactic vaccines based on ancestor strain during the Omicron-dominant period. S-268019-b demonstrated immunogenicity and was well-tolerated
Pharmacologic Stem Cell Based Intervention as a New Approach to Osteoporosis Treatment in Rodents
Background: Osteoporosis is the most prevalent skeletal disorder, characterized by a low bone mineral density (BMD) and bone structural deterioration, leading to bone fragility fractures. Accelerated bone resorption by osteoclasts has been established as a principal mechanism in osteoporosis. However, recent experimental evidences suggest that inappropriate apoptosis of osteoblasts/osteocytes accounts for, at least in part, the imbalance in bone remodeling as occurs in osteoporosis. The aim of this study is to examine whether aspirin, which has been reported as an effective drug improving bone mineral density in human epidemiology studies, regulates the balance between bone resorption and bone formation at stem cell levels. Methods and Findings: We found that T cell-mediated bone marrow mesenchymal stem cell (BMMSC) impairment plays a crucial role in ovariectomized-induced osteoporosis. Ex vivo mechanistic studied revealed that T cell-mediated BMMSC impairment was mainly attributed to the apoptosis of BMMSCs via the Fas/Fas ligand pathway. To explore potential of using pharmacologic stem cell based intervention as an approach for osteoporosis treatment, we selected ovariectomy (OVX)-induced osteoporosis mouse model to examine feasibility and mechanism of aspirin-mediated therapy for osteoporosis. We found that aspirin can inhibit T cell activation and Fas ligand induced BMMSC apoptosis in vitro. Further, we revealed that aspirin increases osteogenesis of BMMSCs by aiming at telomerase activity and inhibits osteoclast activity in OVX mice, leading to ameliorating bone density. Conclusion: Our findings have revealed a novel osteoporosis mechanism in which activated T cells induce BMMSC apoptosis via Fas/Fas ligand pathway and suggested that pharmacologic stem cell based intervention by aspirin may be a new alternative in osteoporosis treatment including activated osteoblasts and inhibited osteoclasts. © 2008 Yamaza et al
Regenerative endodontics: a true paradigm shift or a bandwagon about to be derailed?
Aims: Regenerative endodontic techniques (RETs) have been hailed as a paradigm shift for the management of traumatised non-vital immature permanent anterior teeth. In this article the aim was to critically appraise the literature with regards to the outcome of regenerative endodontics on root development. Methods: Critical review of the literature where regenerative endodontic techniques have been used in the management of immature non-vital teeth with continuation of root development as the main outcome reported. Results: Most studies published were in the form of case reports and series with very few randomised controlled trials with a high risk of bias. Continuation of root development following the use of RET has been shown to be unpredictable at best with lower success in those teeth losing vitality as a result of dental trauma. Conclusions: Despite the high success of regenerative endodontics in terms of periodontal healing including resolution of clinical and radiographic signs and symptoms of infection, continuation of root development remains an unpredictable outcome. The use of a blood clot as a scaffold in regenerative endodontics should be reviewed carefully as that might offer an environment for repair rather than regeneration. In addition, preservation of structures, such as Hertwig’s epithelial root sheath, may have an important bearing on the success of this approach and should be further investigated
Candida albicans Isolates from the Gut of Critically Ill Patients Respond to Phosphate Limitation by Expressing Filaments and a Lethal Phenotype
Candida albicans is an opportunistic pathogen that proliferates in the intestinal tract of critically ill patients where it continues to be a major cause of infectious-related mortality. The precise cues that shift intestinal C. albicans from its ubiquitous indolent colonizing yeast form to an invasive and lethal filamentous form remain unknown. We have previously shown that severe phosphate depletion develops in the intestinal tract during extreme physiologic stress and plays a major role in shifting intestinal Pseudomonas aeruginosa to express a lethal phenotype via conserved phosphosensory-phosphoregulatory systems. Here we studied whether phosphate dependent virulence expression could be similarly demonstrated for C. albicans. C. albicans isolates from the stool of critically ill patients and laboratory prototype strains (SC5314, BWP17, SN152) were evaluated for morphotype transformation and lethality against C. elegans and mice during exposure to phosphate limitation. Isolates ICU1 and ICU12 were able to filament and kill C. elegans in a phosphate dependent manner. In a mouse model of intestinal phosphate depletion (30% hepatectomy), direct intestinal inoculation of C. albicans caused mortality that was prevented by oral phosphate supplementation. Prototype strains displayed limited responses to phosphate limitation; however, the pho4Δ mutant displayed extensive filamentation during low phosphate conditions compared to its isogenic parent strain SN152, suggesting that mutation in the transcriptional factor Pho4p may sensitize C. albicans to phosphate limitation. Extensive filamentation was also observed in strain ICU12 suggesting that this strain is also sensitized to phosphate limitation. Analysis of the sequence of PHO4 in strain ICU12, its transcriptional response to phosphate limitation, and phosphatase assays confirmed that ICU12 demonstrates a profound response to phosphate limitation. The emergence of strains of C. albicans with marked responsiveness to phosphate limitation may represent a fitness adaptation to the complex and nutrient scarce environment typical of the gut of a critically ill patient
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