Dental unit waterline testing practices: an 11-Year retrospective study.

OBJECTIVES: This retrospective study examined the dental unit waterline (DUWL) testing practices of Saskatchewan dental clinics over a period of 11 years, with an emphasis on their responses after identification of high microbial levels. MATERIALS AND METHODS: Dental clinics (n = 137) aseptically collected samples of output water from their air/water syringes, handpieces, and ultrasonic scaler lines using Sigma-Aldrich® waterline test kits and delivered them to a quality assurance laboratory. Tests were incubated for seven days at room temperature, and those with heterotrophic plate counts > 500 CFU/mL were reported as failures. Statistical analyses were performed on a database containing 4,093 test results. RESULTS: Participating clinics submitted an average of 11 DUWL tests per year. Overall, 21% of tests failed, and a moderate positive association (rs=.52, p < 0.001) was found between clinics' DUWL testing frequency and failure rate. Only 7% of failed DUWL tests were followed up by collection of a subsequent test within two weeks, of which 47% still exceeded the 500 CFU/mL threshold. CONCLUSIONS: Our findings demonstrate an association between DUWL testing frequency and detection of unacceptable microbial levels, along with infrequent retesting and often-inadequate intervention after a failed test. This suggests the need for further efforts at the regulatory and educational levels to maintain adequate water quality during dental treatment. CLINICAL RELEVANCE: Procedural water can become contaminated in DUWLs and endanger patients. Regular DUWL monitoring and evidence-based interventions to treat contaminated systems are necessary to safeguard patient health.

Salivary changes in chronic kidney disease and in patients undergoing hemodialysis: a systematic review and meta-analysis.

OBJECTIVES: This study is aimed at describing changes in salivary flow rate and ionic composition present in the saliva of chronic kidney disease (CKD) patients by assessing the pH, calcium, phosphate, and phosphorus concentrations and comparing them to healthy individuals, along with exploring the influence of hemodialysis on these parameters. METHODS: The bibliographical search was performed in nine databases to find all types of studies, including observational clinical studies, without restrictions regarding publication year or language. Two reviewers selected the studies, extracted the data, and assessed the risk of bias using JBI tools. Random-effect meta-analysis was performed with the standardized mean difference (SMD) as effect estimate, at a 95% confidence interval. RESULTS: Thirty-three studies were included in the qualitative synthesis and 31 studies were included in the meta-analysis. Chronic kidney disease patients presented lower salivary flow rate (SMD: - 1.73; 95% CI = - 2.14; - 1.31), higher pH (SMD: 1.57; 95% CI = 1.11; 2.03), and higher phosphorus concentration (SMD: 0.86; 95% CI = 0.63; 1.09) in saliva. Concurrently, salivary flow rate and pH presented significant changes after hemodialysis, with higher salivary flow rate (SMD: 0.53; 95% CI = 0.25; 0.81) and lower pH (SMD: - 0.53; 95% CI = - 0.88; - 0.19) in patients on hemodialysis treatment. CONCLUSION: Chronic kidney disease patients present reduced salivary flow rate and increased pH and phosphorus concentration in saliva. Hemodialysis can increase the salivary flow rate of these patients.

Chemokine expression is upregulated in chondrocytes in diabetic fracture healing.

Chemokines are thought to play an important role in several aspects of bone metabolism including the recruitment of leukocytes and the formation of osteoclasts. We investigated the impact of diabetes on chemokine expression in normal and diabetic fracture healing. Fracture of the femur was performed in streptozotocin-induced diabetic and matched normoglycemic control mice. Microarray analysis was carried out and chemokine mRNA levels in vivo were assessed. CCL4 were examined in fracture calluses by immunohistochemistry and the role of TNF in diabetes-enhanced expression was investigated by treatment of animals with the TNF-specific inhibitor, pegsunercept. In vitro studies were conducted with ATDC5 chondrocytes. Diabetes significantly upregulated mRNA levels of several chemokines in vivo including CCL4, CCL8, CCL6, CCL11, CCL20, CCL24, CXCL2, CXCL5 and chemokine receptors CCR5 and CXCR4. Chondrocytes were identified as a significant source of CCL4 and its expression in diabetic fractures was dependent on TNF (P<0.05). TNF-α significantly increased mRNA levels of several chemokines in vitro which were knocked down with FOXO1 siRNA (P<0.05). CCL4 expression at the mRNA and proteins levels was induced by FOXO1 over-expression and reduced by FOXO1 knockdown. The current studies point to the importance of TNF-α as a mechanism for diabetes enhanced chemokine expression by chondrocytes, which may contribute to the accelerated loss of cartilage observed in diabetic fracture healing. Moreover, in vitro results point to FOXO1 as a potentially important transcription factor in mediating this effect.

FOXO1 modulates osteoblast differentiation.

Forkhead box O1 (FOXO1) is upregulated during bone formation and in response to stimulation by bone morphogenetic proteins. Studies presented here examined the functional role of FOXO1 in a well defined culture system in which pre-osteoblastic cells undergo terminal differentiation in vitro. Mineralizing cultures of MC3T3-E1 cells were examined with or without FOXO1 knockdown by RNAi. Normal cells show the upregulation of FOXO1 and RUNX2 DNA binding activity, alkaline phosphatase activity, and mRNA levels of FOXO1, RUNX2, type 1 collagen, osteocalcin and MMP13 during formation of mineralizing nodules. In FOXO1 depleted cells each of these measurements was significantly reduced compared to values in control cells transfected with scrambled siRNA (P<0.05). Depletion of FOXO1 also reduced the number of mineralized nodules formed. Moreover, chromatin immunoprecipitation assays revealed a direct interaction of FOXO1 with the RUNX2 promoter. Overexpression of FOXO1 reduced the MC3T3-E1 cell number and the number of PCNA positive cells with little effect on apoptosis. These findings indicate that FOXO1 plays an important role in promoting osteoblast differentiation and suppressing proliferation in differentiating cells.

The transcription factor ST18 regulates proapoptotic and proinflammatory gene expression in fibroblasts.

Suppression of tumorigenicity 18 (ST18) and the homologues neural zinc-finger protein-3 (NZF3) and myelin transcription factor 3 (Myt3) are transcription factors with unknown function. Previous studies have established that they repress transcription of a synthetic reporter construct consisting of the consensus sequence AAAGTTT linked to the thymidine kinase promoter. In addition, ST18 exhibits significantly reduced expression in breast cancer and breast cancer cell lines. We report here for the first time evidence that ST18 mediates tumor necrosis factor (TNF) -alpha induced mRNA levels of proapoptotic and proinflammatory genes in fibroblasts by mRNA profiling and silencing with ST18 small interfering RNA (siRNA). Gene set enrichment analysis and mRNA profiling support this conclusion by identifying several apoptotic and inflammatory pathways that are down-regulated by ST18 siRNA. In addition, ST18 siRNA reduces TNF-induced fibroblast apoptosis and caspase-3/7 activity. Fibroblasts that overexpress ST18 by transient transfection exhibit significantly increased apoptosis and increased expression of TNF-alpha, interleukin (IL) -1alpha, and IL-6. In addition, cotransfection of ST18 and a TNF-alpha or IL-1alpha reporter construct demonstrates that ST18 overexpression in fibroblasts significantly enhanced promoter activity of these genes. Taken together, these studies demonstrate that the transcription factor ST18/NZF3 regulates the mRNA levels of proapoptotic and proinflammatory genes in revealing a previously unrecognized function.

Immunization enhances inflammation and tissue destruction in response to Porphyromonas gingivalis.

It is well established that host-bacterium interactions play a critical role in the initiation and progression of periodontal diseases. By the use of inhibitors, it has been shown that mediators associated with the innate immune response significantly contribute to the disease process. Less is known regarding the role of the acquired immune response. To investigate mechanisms by which the acquired immune response to Porphyromonas gingivalis could affect connective tissue, we used a well-documented calvarial model to study host-bacterium interactions. Injection of P. gingivalis stimulated gamma interferon, interleukin 6, macrophage inflammatory protein 2, and monocyte chemoattractant protein 1 expression as determined by real-time PCR. Prior immunization against P. gingivalis significantly enhanced the mRNA levels of these cytokines and chemokines. Similarly, immunization significantly increased and prolonged the formation of a polymorphonuclear leukocyte and mononuclear cell infiltrate (P < 0.05). In addition, the area of connective tissue destruction, osteoclastogenesis, bone loss, mRNA expression of proapoptotic genes, and degree of fibroblast apoptosis were increased in immunized mice (P < 0.05). These results indicate that activation of the acquired immunity by P. gingivalis increases the inflammatory and destructive responses which occur in part through up-regulating the innate immune response and enhancing osteoclastogenesis and fibroblast apoptosis.