Salivary Nickel and Chromium Levels in Orthodontic Patients with and Without Periodontitis: a Preliminary Historical Cohort Study

Many periodontal patients may need orthodontic treatment. Alterations in oral environment particularly the reduction of pH in periodontal patients could affect metal ion release from orthodontic appliances. However, there is no study on metal ion release in periodontal patients. The aim of this preliminary study was to comparatively evaluate, for the first time, salivary levels of nickel and chromium in periodontal patients (versus healthy controls) under orthodontic treatment for 2 months. In this in vivo study, 40 subjects were evaluated. Patient selection and standardization of orthodontic treatment protocols were prospectively designed and performed. Two groups of n = 20 each (control: healthy orthodontic patients, cohort: orthodontic patients with periodontitis) underwent similar protocols of fixed orthodontic treatment for 2 months. After 2 months, salivary nickel and chromium concentrations of the case and cohort groups were measured using inductively coupled plasma mass spectrometry (ICP-MS). The values were compared between the two groups using t test. There were 10 men and 10 women in each group. The mean age of patients was 34.6 ± 3.6 years old. The salivary level of nickel was 338.2 ± 235.5 ng/ml and 182.8 ± 116.5 ng/ml in the cohort and control groups, respectively (P = 0.0118). The salivary level of chromium was 7.4 ± 3.15 ng/ml in the cohort and 6.35 ± 2.39 ng/ml in the control group (P = 0.2214). Salivary level of nickel might be considerably higher in periodontal patients undergoing 2 months of orthodontic treatment compared to orthodontic patients with healthy gingivae.

     

Prevalence and determinants of diabetes mellitus among Iranian patients with chronic liver disease

BACKGROUND: Alterations in carbohydrate metabolism are frequently observed in cirrhosis. We conducted this study to define the prevalence of diabetes mellitus (DM) and impaired glucose tolerance (IGT) in Iranian patients with chronic liver disease (CLD), and explore the factors associated with DM in these patients. METHODS: One hundred and eighty-five patients with CLD were enrolled into the study. Fasting plasma glucose and two-hour plasma glucose were measured in patients' sera. DM and IGT were diagnosed according to the latest American Diabetes Association criteria. RESULTS: The subjects included 42 inactive HBV carriers with a mean age of 42.2 +/- 12.0 years, 102 patients with HBV or HCV chronic hepatitis with a mean age of 41.2 +/- 10.9 years, and 41 cirrhotic patients with a mean age of 52.1 +/- 11.4 years. DM and IGT were diagnosed in 40 (21.6%) and 21 (11.4%) patients, respectively. Univariate analysis showed that age (P = 0.000), CLD status (P = 0.000), history of hypertension (P = 0.007), family history of DM (P = 0.000), and body mass index (BMI) (P = 0.009) were associated with DM. Using Multivariate analysis, age (OR = 4.7, 95%CI: 1.8-12.2), family history of DM (OR = 6.6, 95%CI: 2.6-17.6), chronic hepatitis (OR = 11.6, 95%CI: 2.9-45.4), and cirrhosis (OR = 6.5, 95%CI: 2.4-17.4) remained as the factors independently associated with DM. When patients with cirrhosis and chronic hepatitis were analyzed separately, higher Child-Pugh's score in cirrhotic patients (OR = 9.6, 95%CI: 1.0-88.4) and older age (OR = 7.2, 95%CI: 1.0-49.1), higher fibrosis score (OR = 59.5, 95%CI: 2.9-1211.3/ OR = 11.9, 95%CI: 1.0-132.2), and higher BMI (OR = 30.3, 95%CI: 3.0-306.7) in patients with chronic hepatitis were found to be associated with higher prevalence of DM. CONCLUSIONS: Our findings indicate that patients with cirrhosis and chronic hepatitis are at the increased risk of DM occurrence. Older age, severe liver disease, and obesity were associated with DM in these patients.     

Molecular basis for regulation of Src by the docking protein p130Cas

The docking protein p130Cas (Cas) becomes tyrosine-phosphorylated in its central substrate domain in response to extracellular stimuli such as integrin-mediated cell adhesion, and transmits signals through interactions with various intracellular signaling molecules such as the adaptor protein Crk. Src-family kinases (SFKs) bind a specific site in the carboxyl-terminal region of Cas and subsequently SFKs phosphorylate progressively the substrate domain in Cas. In this study crystallography, mutagenesis and binding assays were used to understand the molecular basis for Cas interactions with SFKs. Tyrosine phosphorylation regulates binding of Cas to SFKs, and the primary site for this phosphorylation, Y762, has been proposed. A phosphorylated peptide corresponding to Cas residues 759MEDpYDYVHL767 containing the key phosphotyrosine was crystallized in complex with the SH3-SH2 domain of the SFK Lck. The results provide the first structural data for this protein-protein interaction. The motif in Cas 762pYDYV binds to the SH2 domain in a mode that mimics high-affinity ligands, involving dual contacts of Y762 and V765 with conserved residues in SFK SH2 domains. In addition, Y764 is in position to make an electrostatic contact after phosphorylation with a conserved SFK arginine that mediates interactions with other high-affinity SH2 binders. These new molecular data suggest that Cas may regulate activity of Src as a competing ligand to displace intramolecular interactions that occur in SFKs (between the C-terminal tail and the SH2 domain) and restrain and down-regulate the kinase in an inactive form.