Enhancing activity of Pleurotus sajor-caju (Fr.) Sing β-1,3-Glucanoligosaccharide (Ps-GOS) on proliferation, differentiation, and mineralization of MC3T3-E1 cells through the involvement of BMP-2/Runx2/MAPK/Wnt/β-catenin signaling pathway

Osteoporosis is a leading world health problem that results from an imbalance between bone formation and bone resorption. β-glucans has been extensively reported to exhibit a wide range of biological activities, including antiosteoporosis both in vitro and in vivo. However, the molecular mechanisms responsible for β-glucan-mediated bone formation in osteoblasts have not yet been investigated. The oyster mushroom Pleurotus sajor-caju produces abundant amounts of an insoluble β-glucan, which is rendered soluble by enzymatic degradation using Hevea glucanase to generate low-molecular-weight glucanoligosaccharide (Ps-GOS). This study aimed to investigate the osteogenic enhancing activity and underlining molecular mechanism of Ps-GOS on osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells. In this study, it was demonstrated for the first time that low concentrations of Ps-GOS could promote cell proliferation and division after 48 h of treatment. In addition, Ps-GOS upregulated the mRNA and protein expression level of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor-2 (Runx2), which are both involved in BMP signaling pathway, accompanied by increased alkaline phosphatase (ALP) activity and mineralization. Ps-GOS also upregulated the expression of osteogenesis related genes including ALP, collagen type 1 (COL1), and osteocalcin (OCN). Moreover, our novel findings suggest that Ps-GOS may exert its effects through the mitogen-activated protein kinase (MAPK) and wingless-type MMTV integration site (Wnt)/β-catenin signaling pathways

l-Quebrachitol Promotes the Proliferation, Differentiation, and Mineralization of MC3T3-E1 Cells: Involvement of the BMP-2/Runx2/MAPK/Wnt/β-Catenin Signaling Pathway.

Osteoporosis is widely recognized as a major health problem caused by an inappropriate rate of bone resorption compared to bone formation. Previously we showed that d-pinitol inhibits osteoclastogenesis but has no effect on osteoblastogenesis. However, the effect on osteoblast differentiation of its isomer, l-quebrachitol, has not yet been reported. The purpose of this study was, therefore, to investigate whether l-quebrachitol promotes the osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells. Moreover, the molecular mechanism of action of l-quebrachitol was further explored. Here, it is shown for the first time that l-quebrachitol significantly promotes proliferation and cell DNA synthesis. It also enhances mineralization accompanied by increases in mRNA expression of bone matrix proteins including alkaline phosphatase (ALP), collagen type I (ColI), osteocalcin (OCN), and osteopontin (OPN). In addition, l-quebrachitol upregulates the mRNA and protein expression of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor-2 (Runx2), while down-regulating the receptor activator of the nuclear factor-κB ligand (RANKL) mRNA level. Moreover, the expression of regulatory genes associated with the mitogen-activated protein kinase (MAPK) and wingless-type MMTV integration site (Wnt)/β-catenin signaling pathways are also upregulated. These findings indicate that l-quebrachitol may promote osteoblastogenesis by triggering the BMP-2-response as well as the Runx2, MAPK, and Wnt/β-catenin signaling pathway

Bacterial aerosols in the dental clinic: a review

A number of sources of bacterial aerosols exist within and outside the dental clinic. The concentration of bacterial aerosols and splatters appears to be highest during dental procedures, especially those generated by some procedures such as ultrasonic scaling, or using a high speed drill. Several infectious diseases could be transmitted to staff and patients by airborne bacterial and other contaminants in the dental clinic. Air-conditioning and ventilation systems should be regularly maintained to reduce environmental contaminants and to prevent recirculation of bacterial aerosols. Pre-procedural rinsing by patients with mouthwashes as well as vacuum and electrostatic extraction of aerosols during dental procedures could also be employed. Dental staff should also consider appropriate immunisations and continue to use personal protective measures, which reduce contact with bacterial aerosols and splatters in the dental clinic

Occupational risks of modern dentistry: a review

There are many occupational health risks in modern dentistry. These include exposure to infectious diseases (such as hepatitus B and C (HBV and HVC) and human immunodeficiency virus (HIV)), musculoskeletal and other injuries, contact dermatitis, radiation noise, mercury, dental materials and stress. Percutaneous injuries are particular concern to those dentists who may be exposed to serious infectious agents (such as HIV, HBV and HCV), and further education on how to avoid injuries would be beneficial. Dentists should receive HBV immunisation and use personal protective measures and appropriate sterilisation or high-level disinfection techniques. Additional studies are required in order to identify causes of and appropriate interventions for musculoskeletal pain and contact dermatitis - which may reduce thier prevalence. Clearly dentists should be kept up to date with current OHS practices (particularly in areas such as exposure to mercury, radiation and some newer dental materials) through continuing education programs and practice audits

Travel insurance claims made by travellers from Australia for dental conditions

Background: Little is known about dental problems suffered by travellers abroad. This study was designed to investigate travel insurance claims made by travellers from Australia for dental conditions, particularly examining demographic factors, type of travel insurance coverage, nature and duration of travel, when dental treatment was sought during travel, use of emergency assistance, type of treatment, and claim outcome, including cost.\ud \ud Methods: 1,289 claims submitted during 1998–99 to a major Australian-based travel insurance company were examined for dental claims.\ud \ud Results: 104 (8.1%) claims for dental conditions were submitted, of which 45 (43.3%) were made by male and 59 (56.7%) by female travellers. The majority of claimants were in the 60 years and over age group 54 (52.4%). Dental conditions reported required conservative (mostly fillings) 31 (29.8%), endodontic (mostly root canal treatment) 19 (18.3%), prosthodontic 27 (26.0%), periodontal 8 (7.7%), oral and maxillofacial surgery 2 (1.9%) and other or multiple 17 (16.3%) treatments. Use of the travel insurance emergency telephone service for dental conditions was reported in only seven cases (6.7%). Almost two-thirds 64 (61.5%) of claims were accepted. Claims for prosthodontic treatment were significantly less likely to be accepted. The majority of dental conditions did not require further medical investigations, 74 (71.2%). The mean cost of payouts to claims was AU$238.06 for males and AU$182.58 for females. Claims for endodontic and prosthodontic treatment were significantly more expensive than other types of treatment.\ud \ud Conclusions: Claims for dental conditions represent a noteworthy proportion of travel insurance claims made by Australian travellers abroad. More than three-quarters of claims for dental conditions were for conservative, endodontic or prosthodontic treatment. Travellers should be advised to have a dental check-up before departure overseas and to take care with pre-existing dental conditions, which may not be able to be claimed on travel insurance