A bifunctional bortezomib-loaded porous nano-hydroxyapatite/alginate scaffold for simultaneous tumor inhibition and bone regeneration.

Treatments of osteolytic lesions due to malignant metastasis remain one of the major clinical challenges. The residual tumor cells after surgical resections and an acidic tumor microenvironment are unfavorable for osteogenic induction. Bortezomib (BTZ), a proteasome inhibitor used in chemotherapy, also has an osteogenic potential in concentration- and Ca2+-dependent manners. In this study, controlled delivery of BTZ in a novel bifunctional scaffold based on nano-hydroxyapatite (nHA) and sodium alginate (SA) nanocomposite, namely BTZ/nHA@SA, has been explored. By smartly adjusting microenvironments, a sustainable release of Ca2+ from nHA could be achieved, which was not only able to cross-link SA but also to regulate the switch between the dual functions of tumor inhibition and bone regeneration of BTZ to promote the osteogenic pathway. The freeze-dried BTZ/nHA@SA scaffold has excellent interconnectivity, is capable to promote the attachment and proliferation of mouse embryonic osteoblast precursor cells, as well as effectively induces breast cancer cell death in vitro. Furthermore, in vivo, studies using a mouse tumor model and a rabbit femoral defect model showed that the BTZ/nHA@SA scaffold could promote tumor ablation, and also enhance bone repair. Therefore, the BTZ/nHA@SA scaffold has unique dual functions of inhibiting tumor recurrence and promoting bone tissue regeneration simultaneously. This smart bi-functional scaffold offers a promising novel approach for oncological treatments by synchronously orchestrating tumor inhibition and tissue regeneration for the repair of neoplastic bone defects.

Changes in bone graft height and influencing factors after sinus floor augmentation by using the lateral window approach: A clinical retrospective study of 1 to 2 years.

STATEMENT OF PROBLEM: Recent systematic reviews have reported resorption of bone grafts after augmentation, but the influencing factors are numerous and uncertain. Different brands of bone graft and other factors may affect the bone formation effect after sinus floor augmentation. PURPOSE: The purpose of this retrospective clinical study was to evaluate the graft material height changes after sinus floor augmentation with cone beam computed tomography (CBCT) and to investigate the potential influencing factors related to graft resorption. MATERIAL AND METHODS: Four midsagittal cut CBCT images of 157 posterior maxillary implants after maxillary sinus floor elevation by using the lateral window approach with bone grafts from 116 patients were obtained. Four CBCT scans had been performed immediately (T0), 6 months (T1) and 12 months after bone grafting (T2), and 1.5 to 2 years after treatment (T3), and the distance between the implant platform and the grafted mucosa of the maxillary sinus floor was measured at 3 locations. Correlation coefficients of these parameters were calculated. A linear mixed model was used to investigate potential factors influencing graft height reduction, including the patient's sex, age, smoking status, periodontal status, graft brand, implant site, implant level, placement time, and residual bone height. RESULTS: Mean ±standard deviation graft height at the mesial side of the implant (MeGH) was significantly decreased by 0.32 ±0.88 mm in the first 6 months, was gradually reduced after 6 months (0.26 ±0.43 mm), and then 1 to 2 years later increased to 0.39 ±0.97 mm. The changes in graft height at the center of the implant (CeGH) and graft height at the distal side (DiGH) groups were similar to those in the MeGH group. A significantly positive correlation was found among the height alterations in 3 locations (rs=0.954, P<.001). The linear mixed model showed that smoking was more likely to cause graft height reduction in MeGH (P=.034). CONCLUSIONS: Graft height significantly decreased after maxillary sinus augmentation over 1 to 2 years. Smoking had a negative effect on graft height changes, while the 2 brands of graft and other factors had no significant effect.

Implant survival rate and marginal bone loss with the all-on-4 immediate-loading strategy: A clinical retrospective study with 1 to 4 years of follow-up.

STATEMENT OF PROBLEM: Assessing peri-implant marginal bone loss (MBL) and its risk factors with cone beam computed tomography (CBCT) may clarify the risk factors for the all-on-4 (5 or 6) strategy and further improve its survival rate. PURPOSE: The purpose of this retrospective clinical study was to evaluate the implant survival rate, MBL, and associated risk factors of all-on-4 (5 or 6) prostheses after 1 to 4 years of follow-up with CBCT. MATERIAL AND METHODS: A total of 56 participants rehabilitated with 325 implants by using the all-on-4 (5 or 6) concept between October 2015 and December 2019 were included. Outcome measures were cumulative implant survival (life-table analysis) and MBL. Four CBCT scans, a scan immediately after surgery (T0), a scan 1 year after surgery (T1), a scan 2 years after surgery (T2), and a scan 3 to 4 years after treatment (T3), were obtained to evaluate the MBL. The Pearson correlation coefficient analysis and linear mixed models were performed to assess the potential risk factors for MBL (α=.05). RESULTS: The implant survival rate was 99.38%, and the prosthesis survival rate was 100%. The reductions in the vertical buccal bone height (△VBBH) were 0.74 ±0.10 mm (T0-T1), 0.37 ±0.12 mm (T1-T2), and 0.15 ±0.14 mm (T2-T3). Except for T2-T3, the △VBBH showed a significant difference at T0-T1 and T1-T2 (P≤.05). The alterations in vertical mesial bone height (VMBH), vertical distal bone height (VDBH), and vertical lingual bone height (VLBH) were similar to the trend observed in VBBH. The △VBBH (T0-T3) was negatively correlated with the horizontal buccal bone thickness (HBBT) (T0) (r=-.394, P<.001). Linear mixed models revealed that factors such as smoking (P=.001), mandible implant site (P<.001), immediate implant (P=.026), tilted implant (P<.001), female sex (P=.003), systemic disease (P=.025), and bruxism (P=.022) negatively affected MBL. The cantilever length (CL) also had a negative effect on MBL around the implants at the distal extension (P<.001). CONCLUSIONS: The high implant and prosthesis survival rates and low MBL confirmed the predictability of the all-on-4 (5 or 6) concept. Smoking, mandible implant site, systemic disease, bruxism, female sex, immediate implant, tilted implant, and CL were identified as potential risk factors for MBL.

Application of WeChat-based flipped classroom on root canal filling teaching in a preclinical endodontic course.

BACKGROUND: This study was aimed to evaluate the application of WeChat-based flipped classroom in root canal filling teaching in a preclinical endodontic course. METHODS: A two-group comparative study was designed. The pre-class test, on-site quiz, and root canal filling on extracted premolars were performed by students from a lecture-based classroom group (LG, n = 30) and a WeChat-based flipped classroom group (WFG, n = 30). Results of the Pre-class test and on-site quiz were analyzed by independent samples t-test. Post-filling radiographs were taken and evaluated by a specialist in oral radiology who was blinded to grouping. Results of root canal fillings were analyzed by the Pearson chi-square test. Student responses in questionnaires were analyzed by Fisher's exact test. RESULTS: The students in WFG could get significantly higher scores in the on-site test and make better performances in root canal filling than those in LG. In terms of questionnaires, students from WFG were perceived to be more motivated to learn, better to understand the knowledge, better to improve communication and clinical skills, easier to perform root canal filling but spending more time. CONCLUSION: The WeChat-based flipped classroom teaching can have a better effect than lecture-based teaching on root canal filling learning for students with limited endodontic experiences.

Vital Pulp Therapy in Permanent Teeth with Irreversible Pulpitis Caused by Caries: A Prospective Cohort Study.

BACKGROUND: When a tooth is diagnosed with irreversible pulpitis, root canal therapy (RCT) is generally performed to completely remove pulp tissue, which might lead to a higher risk of loss of vascularity, and teeth being more prone to fracture. Vital pulp therapy (VPT) is a personalized method of treating irreversible pulpitis, which conforms to the trend of minimally invasive endodontics. The remaining vital pulp could promote the physiological development of the roots of young permanent teeth with incomplete apical foramen. However, clear guidelines for VPT indication are still missing. OBJECTIVE: This prospective cohort study evaluated the outcomes of vital pulp therapy (VPT) using iRoot BP Plus (Innovative Bioceramix Inc, Vancouver, BC, Canada) in permanent teeth of 6- to 20-year-old patients with irreversible pulpitis caused by caries and analyzed the preoperative factors affecting VPT prognosis. METHODS: Fifty-nine permanent teeth in 59 patients with irreversible pulpitis caused by caries were treated with VPT using iRoot BP Plus. All patients received VPT under a standardized protocol. After informed consent, teeth were isolated with a dental dam, then operators performed VPT with iRoot BP Plus and restored the teeth with composite resin or stainless steel crown. Patients were postoperatively recalled after 3, 6 and 12 months and then recalled annually. Successful cases were defined as successful in both clinical and radiographic evaluations. A statistical analysis was performed using the Fisher exact test, and the level of significant difference was p < 0.05. RESULTS: After 6-36 months of follow-up, a total of 57 teeth from 57 patients were accessible for evaluation. The mean age of subjects was 11.75 ± 3.81 years. The overall clinical and radiographic success rate of VPT was 91.2% (52/57). With an observation time of one year or more, the success rate was 90.5% (38/42). All the symptoms and physical examination findings showed no significant effect on VPT prognosis (p > 0.05) using a binary logistic regression model. CONCLUSIONS: Permanent teeth in 6- to 20-year-old patients diagnosed as irreversible pulpitis caused by caries can be successfully treated with VPT using iRoot BP Plus.

Clinical analysis and a novel risk predictive nomogram for 155 adult patients with hemophagocytic lymphohistiocytosis.

Recently, more and more attention has been paid on adult hemophagocytic lymphohistiocytosis (HLH), a disease with complicated symptoms and high mortality. In order to analyze the clinical characteristics and prediction risk factors of mortality, we designed a retrospective study with 1-year follow-up and included 155 patients admitted to Tongji Hospital diagnosed as HLH. One hundred seven patients formed the training cohort for nomogram development, and 48 patients formed the validation cohort to confirm the model's performance. All patients' clinical characteristics, laboratory results, medical records, and prognosis were analyzed. Among all the 107 patients in the training cohort, 46 were male and 61 were female, with the median age of 49.0 (IQR 31.0-63.0). The 1-year mortality rate was 43.9% (47/107) and 45.8% (22/48) in the training and validation cohort, respectively. And further multivariate logistic regression analysis in the training cohort showed that male (odds ratio 5.534, 95% CI 1.507-20.318, p = 0.010), altered mental status (11.876, 1.882-74.947, p = 0.008), serum ferritin ≥ 31,381 µg/L (8.273, 1.855-36.883, p = 0.006), and IL-6 ≥ 18.59 pg/mL (19.446, 1.527-247.642, p = 0.022) were independent risk factor of mortality. A nomogram included the four prediction factors mentioned above was also tabled to help clinicians evaluate the probability of poor outcome. Area under the receiver operating characteristic curve (AUROC) analysis, calibration curves, and decision curve analysis (DCA) certify the accuracy and the clinical usefulness of the nomogram. Our research reveals that male, altered mental status, serum ferritin ≥ 31,381 µg/L, and IL-6 ≥ 18.59 pg/mL are four independent predictors for poor prognosis. Doctors should pay more attention to patients with altered mental status, high serum ferritin, and IL-6 level, who have a higher risk of death.

Kctd9 Deficiency Impairs Natural Killer Cell Development and Effector Function.

We previously showed that potassium channel tetramerization domain containing 9 (KCTD9) is aberrantly expressed in natural killer (NK) cells in patients with hepatitis B virus-associated acute-on-chronic liver failure and mice with experimental fulminant hepatitis. However, the mechanism underlying the regulation of NK cell function and fulminant hepatitis progression by KCTD9 is unknown. Here, we investigated the role of Kctd9 in regulation of early development, maturation, and function of NK cells using Kctd9-knockout mice. Compared to wild-type mice, Kctd9-deficient mice exhibited impaired NK cell lineage commitment, as evidenced by selective reduction in the refined NK progenitors, and incomplete NK cell maturation, as manifested by a higher proportion of CD11b- NK cells and a lower percentage of CD11b+ NK cells with high proliferative potential. Moreover, Kctd9-depleted NK cells displayed insufficient IFN-γ production, degranulation, and granzyme B production in response to cytokine stimulation, and attenuated cytotoxicity to tumor cells in vitro. The defect in NK cells was further supported by ameliorated liver damage and improved survival in Kctd9-deficient mice following murine hepatitis virus strain-3 (MHV-3) infection, which otherwise leads to immune-mediated fulminant hepatitis, a phenotype homologous to that caused by NK cell depletion in wild-type mice. Further investigation to identify the underlying mechanism revealed that Kctd9 deficiency hindered the expression of transcription factors, including Ets1, Nfil3, Eomes, and Id2 in NK cells. Collectively, our data reveal that Kctd9 acts as a novel regulator for NK cell commitment, maturation, and effector function.

ß-Estradiol antagonizes the inhibitory effects of caffeine in BMMSCs via the ERß-mediated cAMP-dependent PKA pathway.

Caffeine negatively mediates bone homeostasis to cause bone loss and even osteoporosis. This phenomenon occurs in postmenopausal women with estrogen deficiency but not in healthy young women. In this study, we determined whether the effects of caffeine on bone homeostasis were antagonized by estrogen and the underlying mechanisms. In particular, because high levels of cAMP, an important second messenger, have been observed in postmenopausal women suffering from osteoporosis, we examined the role of cAMP in the effects of caffeine on bone homeostasis. In vivo study showed that caffeine accelerated bone loss in osteoporotic rats, whereas ß-estradiol blunted the negative effect of caffeine on bone. In vitro study, we harvested bone marrow-derived mesenchymal stromal cells (BMMSCs) from osteoporotic rats. We found that caffeine and ß-estradiol inversely affected BMMCSs proliferation, apoptosis, osteogenic lineage commitment, extracellular matrix synthesis and mineralization. These parameters were assessed according to the expression levels of osteogenic markers, alkaline phosphatase activity and Alizarin red staining. The deleterious effects of caffeine on BMMSCs were blunted by ß-estradiol. The cAMP-dependent PKA pathway was found to be involved in regulating caffeine/ß-estradiol-mediated cell growth, survival and osteogenesis. Additionally, after estrogen receptor (ER) ß knockdown, the antagonistic effects of ß-estradiol on caffeine were nearly abolished. These results indicated that by binding to ERß, ß-estradiol antagonizes the negative impacts of caffeine on cell growth and osteogenic differentiation in BMMSCs through the cAMP-dependent PKA signaling pathway.

Angiotensin II/Angiotensin II Receptor Blockade Affects Osteoporosis via the AT1/AT2-Mediated cAMP-Dependent PKA Pathway.

Animal studies have reported on the benefits of ARB on bone mass. However, the underlying mechanism for angiotensin II (AngII)/AngII receptor blockade (ARB) in regulating bone mass remains elusive. Since high levels of plasma and urine cAMP are observed in osteoporotic and hypertensive patients, we hypothesized that cAMP may be an important molecule for the downstream events of the activation of AT receptors, members of the G-protein-coupled receptor family, in regulating bone turnover. In this study, micro-CT and X-ray analyses indicated that AngII decreased bone mass via biasing bone resorption over bone formation in osteoporotic mice. However, these adverse effects were blocked by olmesartan and PD123319. In vitro, AngII was shown to downregulate osteogenic differentiation and matrix mineralization, but to upregulate osteoclastic activity by mainly affecting osteoblasts producing osteoclastogenesis-associated key soluble factors, including M-CSF and RANKL. Similarly, ARB treatment exhibited antagonistic effects on AngII. In conclusion, osteoblasts are the directly targeted cells. ARB1 exhibits a greater capacity to increase bone mass than ARB2. The cAMP-dependent PKA pathway plays an important role in AngII/ARB on changing bone mass.

A few selected contributions to electron and photon collisions with H2 and H 2 + .

We discuss a number of aspects regarding the physics of H 2 + and H2. This includes low-energy electron scattering processes and the interaction of both weak (perturbative) and strong (ultrafast/intense) electromagnetic radiation with those systems.

Gene expression profiling of bone marrow-derived stromal cells seeded onto a sandblasted, large-grit, acid-etched-treated titanium implant surface: The role of the Wnt pathway.

OBJECTIVE: The physical and chemical characteristics of the titanium implant surface have been shown to influence dental implant fixation. However, the underlying mechanism by which sandblasted, large-grit, acid-etched (SLA) treatment affects osseointegration remains elusive. METHODS: In the present study, the involved target genes and pathways for SLA treatment, which is an extensively used implant surface modification on improving osseointegration, were identified by in vitro microarray and bioinformatics analyses. RESULTS: A total of 19 genes were differentially expressed after SLA treatment, which included Apc2, Fzd1, Frzb, Wnt16, Fzd2, Plau, Wnt5b, Wnt5a, Lrp6, Wnt9a, Sfrp4, Prkch, Calcoco1, Ccnd1, Wif1, Fzd4, Myc, LRP5, and Lect2. Interaction pathway analyses showed that the Wnt pathway was the most relevant signal after SLA treatment. To ensure the reliability of microarray data, LRP5 was shown to positively regulate osteogenic commitment, extracellular matrix synthesis, and mineralization for BMMSCs seeded onto an SLA-treated titanium surface. However, with LRP5 shRNA treatment, the reduction in calcium deposition in the SLA-treated group was more severe than that observed in cells seeded onto SLA-untreated titanium surface, suggesting that the function of LRP5 was reinforced in the SLA-treated group. In addition, the present study demonstrated that the ß-catenin/LRP5 pathway was responsible for the enhanced osteogenic responses of BMMSCs on SLA-treated titanium surface. CONCLUSIONS: The findings of the present study serve as an initial step towards understanding the mechanism underlying SLA treatment in osseointegration.

Whole body vibration improves osseointegration by up-regulating osteoblastic activity but down-regulating osteoblast-mediated osteoclastogenesis via ERK1/2 pathway.

Due to the reduction in bone mass and deterioration in bone microarchitecture, osteoporosis is an important risk factor for impairing implant osseointegration. Recently, low-magnitude, high-frequency (LMHF) vibration (LM: <1×g; HF: 20-90Hz) has been shown to exhibit anabolic, but anti-resorptive effects on skeletal homeostasis. Therefore, we hypothesized that LMHF loading, in terms of whole body vibration (WBV), may improve implant fixation under osteoporotic status. In the in vivo study, WBV treatment (magnitude: 0.3g, frequency: 40Hz, time: 30min/12h, 5days/week) was applied after hydroxyapatite-coated titanium implants were inserted in the bilateral tibiae of ovariectomized rats. The bone mass and the osteospecific gene expressions were measured at 12weeks post implantation. In the in vitro study, the cellular and molecular mechanisms underlying osteoblastic and osteoclastic activities were fully investigated using various experimental assays. Micro-CT examination showed that WBV could enhance osseointegration by improving microstructure parameters surrounding implants. WBV-regulated gene levels in favor of bone formation over resorption may be the reason for the favorable adaptive bone remolding on bone-implant surface. The in vitro study showed that vibration (magnitude: 0.3g, frequency: 40Hz, time: 30min/12h) up-regulated osteoblast differentiation, matrix synthesis and mineralization. However, mechanically regulated osteoclastic activity was mainly through the effect on osteoblastic cells producing osteoclastogenesis-associated key soluble factors, including RANKL and M-CSF. Osteoblasts were therefore the direct target cells during the mechanotransduction process. The ERK1/2 pathway was demonstrated to play an essential role in vibration-induced enhancement of bone formation and decreased bone resorption. Our data suggests that WBV was a helpful non-pharmacological intervention for improving osseointegration under osteoporosis.

N-acetyl-heparin attenuates acute lung injury caused by acid aspiration mainly by antagonizing histones in mice.

Acute lung injury (ALI) is the leading cause of death in intensive care units. Extracellular histones have recently been recognized to be pivotal inflammatory mediators. Heparin and its derivatives can bind histones through electrostatic interaction. The purpose of this study was to investigate 1) the role of extracellular histones in the pathogenesis of ALI caused by acid aspiration and 2) whether N-acetyl-heparin (NAH) provides more protection than heparin against histones at the high dose. ALI was induced in mice via intratracheal instillation of hydrochloric acid (HCl). Lethality rate, blood gas, myeloperoxidase (MPO) activity, lung edema and pathological changes were used to evaluate the degree of ALI. Heparin/NAH was administered intraperitoneally, twice a day, for 3 days or until death. Acid aspiration caused an obvious increase in extracellular histones. A significant correlation existed between the concentration of HCl aspirated and the circulating histones. Heparin/NAH (10 mg/kg) improved the lethality rate, blood gas, MPO activity, lung edema and pathological score. At a dose of 20 mg/kg, NAH still provided protection, however heparin tended to aggravate the injury due to hemorrhagic complications. The specific interaction between heparin and histones was verified by the binding assay. In summary, high levels of extracellular histones can be pathogenic in ALI caused by acid aspiration. By neutralizing extracellular histones, heparin/NAH can offer similar protection at the moderate doses. At the high dose, NAH provides better protection than heparin.

Angiogenic/osteogenic response of BMMSCs on bone-derived scaffold: effect of hypoxia and role of PI3K/Akt-mediated VEGF-VEGFR pathway.

Bone tissue deficiency is a common clinical challenge. Tissue-engineered bone constructs are an effective approach for the repair of orthopedic bone defects. Mimicking the essential components of the in vivo microenvironment is an efficient way to develop functional constructs. In this study, bone marrow-derived mesenchymal stromal cells (BMMSCs) were seeded into bone-derived scaffolds, a material with similar structure to natural bone. This was done under hypoxic conditions, an environment that imitates that experienced by BMMSCs in vivo. Our data indicate that hypoxia (5% O2 ) significantly increases the proliferation of BMMSCs seeded in scaffolds. As reflected by highly expressed osteogenesis- and angiogenesis-associated biomarkers, including vascular endothelial growth factor (VEGF), RUNX2, bone morphogenetic protein-2/4 and osteopontin, hypoxia also significantly increases the osteogenic and angiogenic responses of BMMSCs seeded into bone-derived scaffold composites. PI3K/Akt-mediated regulation of VEGF-activated VEGFR1/2 signaling is important for hypoxia-induced proliferative/osteogenic/angiogenic responses in BMMSC cellular scaffolds. The combination of bone-derived scaffolds and hypoxia is conducive to the differentiation of BMMSCs into functional tissue-engineered scaffold composites.

Hypoxia induces osteogenic/angiogenic responses of bone marrow-derived mesenchymal stromal cells seeded on bone-derived scaffolds via ERK1/2 and p38 pathways.

Osteogenesis and angiogenesis are tightly coupled processes during bone development and formation. It is thus well known that the enhancement of vascularization is of great importance in bone tissue engineering. As a potential approach for repairing bone defects, bone tissue constructs should therefore replicate the essential components in vivo microenvironments to promote cell osteogenic differentiation while at same time induce angiogenic response. In light of standpoint above, a combination of human bone-derived scaffolds and BMSCs that subjected to hypoxia was used to mimic in vivo conditions. Also the underlying cellular/molecular regulation was fully investigated. The results showed that hypoxia (5-10% O2 ) greatly enhanced the proliferation of BMSCs seeded in scaffolds, although the hypoxia (5% O2 )-induced proliferative effect on BMSC cellular scaffolds was not apparent to those cultured in plates. However, such a kind of model was able to significantly induce the osteogenic/angiogenic responses of BMSCs as reflected by osteogenesis or angiogenesis-related highly expressed genes or proteins, such as alkaline phosphatase, osteocalcin, hypoxia-inducible factor-1α and vascular endothelial growth factor. Moreover, ERK1/2 and/or p38 pathways were demonstrated to play essential roles in hypoxia-induced osteogenic/angiogenic responses. Our results indicated that the combination of bone-derived scaffolds, a material that has a three dimensional network structure, and hypoxia, an environment that replicates in vivo BMSCs hypoxic living conditions, may be a potential approach for creating functional tissue-engineered bone.

Effects of compounds found in Nidus Vespae on the growth and cariogenic virulence factors of Streptococcus mutans.

Nidus Vespae (honeycomb) is a kind of traditional Chinese medicine that has been demonstrated to inhibit the growth and acid-production of oral cariogenic bacteria. Subsequent studies showed that the chloroform/methanol (Chl/MeOH) chemical extraction of Nidus Vespae was the most effective inhibitor of growth and acidogenicity of Streptococcus mutans. In this study, we isolated the chemical compounds of the Nidus Vespae Chl/MeOH extraction, tested their antimicrobial activity against six cariogenic bacteria and further evaluated the acid inhibition properties, anti-F-ATPase activity and anti-LDH activity against S. mutans. The isolated flavonoids, quercetin and kaempferol, inhibited the growth of bacteria (S. mutans, Streptococcus sobrinus, Streptococcus sanguis, Actinomyces viscosus, Actinomyces naeslundii and Lactobacillus rhamnosus) with minimum inhibitory concentrations (MICs) ranging from 1 to 4 mg/ml and minimum bactericidal concentrations (MBCs) from 4 to 16 mg/ml. In addition, quercetin and kaempferol at sub-MIC levels significantly inhibited acidogenicity and acidurity of S. mutans cells. Treated with the test agents, the F-ATPase activity was reduced by 47.37% with 1mg/ml quercetin and by 49.66% with 0.5mg/ml kaempferol. The results showed that quercetin and kaempferol contained in Chl/MeOH extraction presented remarkably biological activity, suggesting that Nidus Vespae might be useful as a potential preventive and therapeutic agent in dental caries.

Reciprocal roles of angiotensin II and Angiotensin II Receptors Blockade (ARB) in regulating Cbfa1/RANKL via cAMP signaling pathway: possible mechanism for hypertension-related osteoporosis and antagonistic effect of ARB on hypertension-related osteoporosis.

Hypertension is a risk factor for osteoporosis. Animal and epidemiological studies demonstrate that high blood pressure is associated with increased calcium loss, elevated parathyroid hormone, and increased calcium movement from bone. However, the mechanism responsible for hypertension-related osteoporosis remains elusive. Recent epidemiological studies indicate the benefits of Angiotensin II Receptors Blockade (ARB) on decreasing fracture risks. Since receptors for angiotensin II, the targets of ARB, are expressed in both osteoblasts and osteoclasts, we postulated that angiotensin II plays an important role in hypertension-related osteoporosis. Cbfa1 and RANKL, the important factors for maintaining bone homeostasis and key mediators in controlling osteoblast and osteoclast differentiation, are both regulated by cAMP-dependent signaling. Angiotensin II along with factors such as LDL, HDL, NO and homocysteine that are commonly altered both in hypertension and osteoporosis, can down-regulate the expression of Cbfa1 but up-regulate RANKL expression via the cAMP signaling pathway. We thus hypothesized that, by altering the ratio of Cbfa1/RANKL expression via the cAMP-dependent pathway, angiotensin II differently regulates osteoblast and osteoclast differentiation leading to enhanced bone resorption and reduced bone formation. Since ARB can antagonize the adverse effect of angiotensin II on bone by lowering cAMP levels and modifying other downstream targets, including LDL, HDL, NO and Cbfa1/RANKL, we propose the hypothesis that the antagonistic effects of ARB may also be exerted via cAMP signaling pathway.

Osteogenic differentiation of bone marrow-derived mesenchymal stromal cells on bone-derived scaffolds: effect of microvibration and role of ERK1/2 activation.

Although in vivo studies have shown that low-magnitude, high-frequency (LMHF) vibration (LM: < 1 ×g; HF: 20-90 Hz) exhibits anabolic effects on skeletal homeostasis, the underlying cellular/molecular regulation involved in bone adaptation to LMHF vibration is little known. In this report, we tested the effects of microvibration (magnitude: 0.3 ×g, frequency: 40 Hz, amplitude: ± 50 µm, 30 min/12 h) on proliferation and osteodifferentiation of bone marrow-derived mesenchymal stromal cells (BMSCs) seeded on human bone-derived scaffolds. The scaffolds were prepared by partial demineralisation and deproteinisation. BMSCs were allowed to attach to the scaffolds for 3 days. Morphological study showed that spindle-shaped BMSCs almost completely covered the surface of bone-derived scaffold and these cells expressed higher ALP activity than those cultured on plates. After microvibration treatment, BMSC proliferation was decreased on day 7 and 10; however, numbers of genes and proteins expressed during osteogenesis, including Cbfa1, ALP, collagen I and osteocalcin were greatly increased. ERK1/2 activation was involved in microvibration-induced BMSC osteogenesis. Taken together, this study suggests that bone-derived scaffolds have good biocompatibility and show osteoinductive properties. By increasing the osteogenic lineage commitment of BMSCs and enhancing osteogenic gene expressions, microvibration promotes BMSC differentiation and increase bone formation of BMSCs seeded on bone-derived scaffolds. Moreover, ERK1/2 pathway plays an important role in microvibration-induced osteogenesis in BMSC cellular scaffolds.

Reciprocal roles between caffeine and estrogen on bone via differently regulating cAMP/PKA pathway: the possible mechanism for caffeine-induced osteoporosis in women and estrogen's antagonistic effects.

Caffeine is consumed by most people in Europe and North America. As a risk factor for osteoporosis, caffeine has been reported to decrease bone mineral density, negatively influence calcium absorption and increase the risk of bone fracture in women. Except for the epidemiological observations and several studies which proved caffeine's unfavorable effects on osteoblast proliferation and impaired ability to form bone, little mechanism is known for the caffeine-induced osteoporosis. Since our unpublished studies showed that the precursor cells of osteoblasts, bone marrow-derived mesenchymal stem cells (BMSCs), were more sensitive than osteoblasts when exposed to the same dose of caffeine. We herein hypothesize that MSCs may be the primary target cells for caffeine-induced osteoporosis. It is well established that increasing cyclic 3',5'-adenosine monophosphate (cAMP) can regulate the expression of key genes involved in bone metabolism, including Cbfa1, PPARgamma, RANKL and OPG. We thereby propose the hypothesis that caffeine, a known inhibitor of cAMP phosphodiesterase, may affect bone metabolism by activating cAMP-dependent protein kinase A (PKA) pathway. In addition, considering the fact observed in epidemiology that caffeine's negative effects on bone only occurred in postmenopausal women and the inverse roles of caffeine and estrogen on bone metabolism, we postulate that caffeine may exert its undesirable influences on bone only in absence or low level of estrogen in vivo and estrogen may antagonize the adverse effect of caffeine on bone. Since several studies have demonstrated that estrogen may have ability to temper the biological effects of cAMP stimulators' roles on bone through cAMP to regulate some important genes' expression in bone metabolism. We assume that estrogen may block cAMP-dependent PKA pathway which is shared by caffeine, to exhibit its antagonistic roles.

Complete breakup of the helium atom by proton and antiproton impact.

We present a fully ab initio, nonperturbative, time-dependent approach to describe single and double ionization of helium by proton and antiproton impact. The problem is discretized by a flexible finite-element discrete-variable representation on the radial grid. Good agreement with the most recent experimental data for absolute angle-integrated cross sections is obtained for projectile energies between 3 keV and 6 MeV. Also, angle-differential cross sections for two-electron ejection are predicted for a proton impact energy of 6 MeV. The time evaluation of the ionization process is portrayed by displaying the electron density as a function of the projectile location.