Elucidation of the chain of disease transmission and identification of the source of coronavirus disease 2019 (COVID-19) infections are crucial for effective disease containment. We describe an ...epidemiological investigation that, with use of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological assays, established links between three clusters of COVID-19.
In Singapore, active case-finding and contact tracing were undertaken for all COVID-19 cases. Diagnosis for acute disease was confirmed with RT-PCR testing. When epidemiological information suggested that people might have been nodes of disease transmission but had recovered from illness, SARS-CoV-2 IgG serology testing was used to establish past infection.
Three clusters of COVID-19, comprising 28 locally transmitted cases, were identified in Singapore; these clusters were from two churches (Church A and Church B) and a family gathering. The clusters in Church A and Church B were linked by an individual from Church A (A2), who transmitted SARS-CoV-2 infection to the primary case from Church B (F1) at a family gathering they both attended on Jan 25, 2020. All cases were confirmed by RT-PCR testing because they had active disease, except for A2, who at the time of testing had recovered from their illness and tested negative. This individual was eventually diagnosed with past infection by serological testing. ELISA assays showed an optical density of more than 1·4 for SARS-CoV-2 nucleoprotein and receptor binding domain antigens in titres up to 1/400, and viral neutralisation was noted in titres up to 1/320.
Development and application of a serological assay has helped to establish connections between COVID-19 clusters in Singapore. Serological testing can have a crucial role in identifying convalescent cases or people with milder disease who might have been missed by other surveillance methods.
National Research Foundation (Singapore), National Natural Science Foundation (China), and National Medical Research Council (Singapore).
Aim
To compare the mineralization inductive capacity of Biodentine and Bioaggregate with Mineral trioxide aggregate (MTA) and to investigate possible signaling pathways of mineralization in human ...dental pulp cells (HDPCs).
Methodology
Viability of HDPCs in response to Biodentine, Bioaggregate, and MTA was measured using 3‐4,5‐dimethylthiazol‐2‐yl‐2,5 diphenyltetrazolium bromide. To investigate their potential to induce odontoblast differentiation, expression of dentine sialophosphoprotein (DSPP) and dentine matrix protein1 (DMP1) mRNA level was evaluated by RT‐PCR. For the mineralized nodule assay, Alizarin red staining was performed. To determine the role of MAPK signaling in the odontoblastic differentiation of HDPCs, activated MAPKs were investigated by Western blot and the effect of MAPK inhibitor was examined by Alizarin red S staining. The results were statistically analysed using one‐way anova and the Bonferroni test.
Results
The effects of MTA, Biodentine, and Bioaggregate on cell viability were similar. Biodentine and Bioaggregate enhanced DSPP and DMP1 mRNA expression compared to the control group, but to the same extent as MTA (P < 0.05). MTA, Biodentine, and Bioaggregate increased the area of calcified nodules compared to the control (P < 0.01). MTA, Biodentine, and Bioaggregate increased phosphorylation of extracellular signal‐regulated kinase (ERK), p38, and c‐Jun N‐terminal kinase (JNK). MAPK inhibitors attenuated mineralized nodule formation, which was increased by MTA, Biodentine, and Bioaggregate, respectively (P < 0.01).
Conclusion
Biodentine and Bioaggregate stimulated odontoblastic differentiation and mineralization nodule formation by activating the MAPK pathway as did MTA. This suggests that the new materials could be useful for regenerative endodontic procedures.
The cause of chronic inflammatory periodontitis, which leads to the destruction of periodontal ligament and alveolar bone, is multifactorial. An increasing number of studies have shown the clinical ...significance of NLRP3-mediated low-grade inflammation in degenerative disorders, but its causal linkage to age-related periodontitis has not yet been elucidated. In this study, we investigated the involvement of the NLRP3 inflammasome and the therapeutic potential of NLRP3 inhibition in age-related alveolar bone loss by using in vivo and in vitro models. The poor quality of alveolar bones in aged mice was correlated with caspase-1 activation by macrophages and elevated levels of IL-1β, which are mainly regulated by the NLRP3 inflammasome, in periodontal ligament and serum, respectively. Aged mice lacking Nlrp3 showed better bone mass than age-matched wild-type mice via a way that affects bone resorption rather than bone formation. In line with this finding, treatment with MCC950, a potent inhibitor of the NLRP3 inflammasome, significantly suppressed alveolar bone loss with reduced caspase-1 activation in aged mice but not in young mice. In addition, our in vitro studies showed that the addition of IL-1β encourages RANKL-induced osteoclastogenesis from bone marrow–derived macrophages and that treatment with MCC950 significantly suppresses osteoclastic differentiation directly, irrelevant to the inhibition of IL-1β production. Our results suggest that the NLRP3 inflammasome is a critical mediator in age-related alveolar bone loss and that targeting the NLRP3 inflammasome could be a novel option for controlling periodontal degenerative changes with age.
Patients with cortical dysplasia (CD) are difficult to treat because the MRI abnormality may be undetectable. This study determined whether fluorodeoxyglucose (FDG)-PET/MRI coregistration enhanced ...the recognition of CD in epilepsy surgery patients.
Patients from 2004-2007 in whom FDG-PET/MRI coregistration was a component of the presurgical evaluation were compared with patients from 2000-2003 without this technique. For the 2004-2007 cohort, neuroimaging and clinical variables were compared between patients with mild Palmini type I and severe Palmini type II CD.
Compared with the 2000-2003 cohort, from 2004-2007 more CD patients were detected, most had type I CD, and fewer cases required intracranial electrodes. From 2004-2007, 85% of type I CD cases had normal non-University of California, Los Angeles (UCLA) MRI scans. UCLA MRI identified CD in 78% of patients, and 37% of type I CD cases had normal UCLA scans. EEG and neuroimaging findings were concordant in 52% of type I CD patients, compared with 89% of type II CD patients. FDG-PET scans were positive in 71% of CD cases, and type I CD patients had less hypometabolism compared with type II CD patients. Postoperative seizure freedom occurred in 82% of patients, without differences between type I and type II CD cases.
Incorporating fluorodeoxyglucose-PET/MRI coregistration into the multimodality presurgical evaluation enhanced the noninvasive identification and successful surgical treatment of patients with cortical dysplasia (CD), especially for the 33% of patients with nonconcordant findings and those with normal MRI scans from mild type I CD.
Abstract
Guided bone regeneration aided by the application of occlusive membranes is a promising therapy for diverse inflammatory periodontal diseases. Symbiosis, homeostasis between the host ...microbiome and cells, occurs in the oral environment under normal, but not pathologic, conditions. Here, we develop a symbiotically integrating occlusive membrane by mimicking the tooth enamel growth or multiple nucleation biomineralization processes. We perform human saliva and in vivo canine experiments to confirm that the symbiotically integrating occlusive membrane induces a symbiotic healing environment. Moreover, we show that the membrane exhibits tractability and enzymatic stability, maintaining the healing space during the entire guided bone regeneration therapy period. We apply the symbiotically integrating occlusive membrane to treat inflammatory-challenged cases in vivo, namely, the open and closed healing of canine premolars with severe periodontitis. We find that the membrane promotes symbiosis, prevents negative inflammatory responses, and improves cellular integration. Finally, we show that guided bone regeneration therapy with the symbiotically integrating occlusive membrane achieves fast healing of gingival soft tissue and alveolar bone.
In a forward screen for genes affecting neurotransmission in
Drosophila, we identified mutations in
dynamin-related protein (
drp1). DRP1 is required for proper cellular distribution of mitochondria, ...and in mutant neurons, mitochondria are largely absent from synapses, thus providing a genetic tool to assess the role of mitochondria at synapses. Although resting Ca
2+ is elevated at
drp1 NMJs, basal synaptic properties are barely affected. However, during intense stimulation, mutants fail to maintain normal neurotransmission. Surprisingly, FM1-43 labeling indicates normal exo- and endocytosis, but a specific inability to mobilize reserve pool vesicles, which is partially rescued by exogenous ATP. Using a variety of drugs, we provide evidence that reserve pool recruitment depends on mitochondrial ATP production downstream of PKA signaling and that mitochondrial ATP limits myosin-propelled mobilization of reserve pool vesicles. Our data suggest a specific role for mitochondria in regulating synaptic strength.
Aim
To explore the involvement of TLR5 in pulp inflammation and to examine the effects of TLR5 activation with its ligand, FlaB protein, on pro‐inflammatory gene expression.
Methodology
TLR5 ...expression in dental pulp tissues and human dental pulp cells (hDPCs) were determined by immunohistochemistry, immunocytochemistry, Western blots and RT‐PCR analyses. To examine the role of TLR5, hDPCs were treated with recombinant FlaB protein (500 ng mL−1) to activate the receptor or with a small interfering RNA against TLR5 (si‐TLR5) to downregulate the receptor. After exposure to FlaB, the expression of inflammation‐related proteins was screened using a protein array kit. Western blots or qRT‐PCR analyses were performed to identify changes in the expression of uPA (urokinase plasminogen activator), TIMPs (tissue inhibitor of metalloproteinases), and IL‐6 and to determine their signalling pathways. Statistical analysis was performed using one‐way analysis of variance (anova) with Tukey post hoc test; P < 0.05 was considered statistically significant.
Result
TLR5 expression was identified in pulp tissues and hDPCs. In the protein array analysis, treatment with FlaB significantly increased uPA expression (P < 0.01) and significantly decreased TIMP1/4 (P < 0.05). FlaB treatment also significantly increased expression of the inflammatory marker IL‐6 (P < 0.01). FlaB treatment increased phosphorylation of the NF‐κB p65 subunit, JNK, p38 and ERK. Chemical inhibitors of NF‐κB (Bay11‐7082), p38 (SB202190) or ERK (U0126) decreased the FlaB induction of uPA expression. Downregulation of TLR5 expression by siRNA decreased the FlaB induction of uPA protein and p65 phosphorylation.
Conclusion
TLR5 activation with FlaB treatment induced the expression of uPA via the NF‐κB and MAPK signalling pathways. Flagellin‐bearing oral bacteria may cause pulp inflammation through TLR5. The findings provide new clues to control pulpal diseases by targeting TLR5 signalling pathways.
Summary
Background
Chronic delta hepatitis virus (HDV) infection rapidly progresses to cirrhosis. Treatment with peginterferon for up to 2 years is often without durable response.
Aim
To examine the ...efficacy and safety of long‐term peginterferon in achieving a durable response.
Methods
Treatment was initiated with 180 μg/week of peginterferon alfa‐2a with titration to a maximal tolerable dose, for up to 5 years. Liver biopsies and hepatic venous pressure gradients (HVPG) were evaluated at baseline, 1, 3 and 5 years. The primary endpoint was histological improvement or loss of serum HDV and HBsAg at 3 years.
Results
Thirteen patients were treated for a median of 140 weeks (6–260) with an average peginterferon dose of 180 μg/week (90–270). At baseline, most had advanced disease (median Ishak fibrosis = 3) with portal hypertension (HVPG = 10.2 ± 6 mmHg). Five of 13 patients (39%) achieved the primary endpoint, with three seroconverting for HBsAg after 24, 37 and 202 weeks of treatment. Histological inflammation improved after 1 year, (median HAI: 10 vs. 7, P = 0.01) with persistence in 4/5 patients at 3 years (median HAI: 7.5). Greatest improvements occurred in the first year. Baseline bilirubin and HBsAg levels were significantly lower in virological responders than nonresponders. After 12 weeks, virological responders had a significant decline in HBsAg (1.5 log10 IU/mL, P = 0.05).
Conclusion
Despite increased doses and duration of therapy, treatment of chronic HDV with peginterferon remains unsatisfactory. Quantitative measures of HBsAg may be an important biomarker of early response to peginterferon therapy in chronic delta hepatitis virus infection.
Aim
To investigate the effect of simvastatin on lipopolysaccharide (LPS)‐stimulated inflammatory cytokines, cell adhesion molecules and nuclear factor‐κB (NF‐κB) transcription factors in human dental ...pulp cells (HDPCs).
Methodology
The effect of LPS and simvastatin on human dental pulp cell (HDPCs) viability was measured using a 3‐4, 5‐dimethylthiazol‐2‐yl‐2, 5 diphenyltetrazolium bromide (MTT) assay. The expression of inflammatory cytokines and cell adhesion molecules was evaluated by reverse‐transcription polymerase chain reaction (RT‐PCR), enzyme‐linked immunosorbent assay (ELISA) and Western blot analysis. NF‐κB transcription factors were evaluated by Western blot analysis. Statistical analysis was performed with analysis of variance (anova).
Results
The viability of cells exposed to different concentrations of E. coli LPS, P. gingivalis LPS and simvastatin was not significantly different compared with that of control cells (P > 0.05). LPS significantly increased interleukin (IL)‐1β (P < 0.05) and IL‐6 mRNA expression (P < 0.05) and vascular cell adhesion molecule‐1 (VCAM‐1) (P < 0.05) and intercellular adhesion molecule‐1 (ICAM‐1) protein expression (P < 0.05) in HDPCs. Treatment with simvastatin significantly attenuated LPS‐stimulated production of IL‐1β, IL‐6, VCAM‐1 and ICAM‐1 (P < 0.05). Treatment with simvastatin decreased LPS‐induced expression of p65 and phosphorylation of IκB and also significantly decreased the phosphorylation of p65 and IκB in the cytoplasm and the level of p65 in the nucleus (P < 0.05).
Conclusions
Simvastatin has a suppressing effect on LPS‐induced inflammatory cytokine, cell adhesion molecules and NF‐κB transcription factors in HDPCs. Therefore, simvastatin might be a useful candidate as a pulp‐capping agent in vital pulp therapy.
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