Protective effect of Copalite surface coating on mercury release from dental amalgam following treatment with carbamide peroxide

Abstract – The effect of Copalite coating on mercury release from dental amalgam following treatment with 10%, 20%, 30% and 40% carbamide peroxide was assessed in vitro, using a cold‐vapour atomic absorption Mercury Analyzer System. Eighty samples of dental amalgam were automatically mixed in a dental amalgamator and condensed into silicon embedding molds. Forty amalgam samples were coated with three uniform layers of Copalite intermediary varnish and the other 40 samples were left uncoated. The coated and non‐coated amalgam samples were exposed for 24 h to 10%, 20%, 30% or 40% carbamide peroxide preparations and compared with samples exposed to phosphate buffer. In the non‐coated samples a significant increase of mercury concentration in solution was found following exposure to all carbamide peroxide preparations tested. Mercury concentration was directly related to carbamide peroxide concentration. In the Copalite‐coated samples, significantly lower concentrations of mercury in solution were found as compared to the non‐coated samples (P<0.01). In conclusion, exposure of amalgam restorations to 10%–40% carbamide peroxide‐based bleaching agents increased the mercury release. Pre‐coating of the external amalgam surfaces with Copalite significantly reduced the release of mercury.     

Significant others benefit from preoperative information

Little attention has been given to the preparation of the patient's family prior to surgery, even though nurses' clinical experience suggests that family members are often more anxious than the patient. This study explored the knowledge and anxiety of spouses and significant others of patients preparing for cardiac surgery. The subjects were selected by convenience from a preoperative class offered at the hospital where surgery was to occur. Before and after the class, the subjects completed a cardiac-surgery knowledge test and an anxiety test. The significant others were significantly more anxious than the patients prior to the class. The anxiety level of significant others was significantly reduced after the class. There were no statistically significant differences between patients and significant others on the cardiac-surgery knowledge test. These results suggest that significant others may benefit from preoperative instruction.     

The association of biliary and pancreatic anomalies with periampullary duodenal diverticula. Correlation with clinical presentations

Fifty-eight symptomatic patients with periampullary duodenal diverticula (PDD) were examined for pancreatic and biliary anomalies using endoscopic retrograde cholangiopancreatography (ERCP), ultrasonography, and other imaging modalities. The pathologic findings in these patients were compared with those in a matched group of 58 patients without PDD, who were simultaneously undergoing a similar investigation for the same clinical presentations. Pathologic findings in the pancreas and/or biliary tree were detected in 70.7% of all patients with PDD, compared with 39.7% in the control group. In patients with PDD, pancreatobiliary anomalies were detected in all patients who presented with jaundice, 85% of patients with pancreatitis, and 27.8% of patients with abdominal pain, as compared with 60%, 40%, and 17%, respectively, in the control group. In 23 patients, ERCP findings demonstrated pancreatobiliary abnormalities that were not detected by other imaging modalities. Fifteen of the patients with PDD and pancreatobiliary anomalies had undergone cholecystectomy between six months and five years previously. We conclude that ERCP is essential in the investigation of all patients with PDD, especially those presenting with jaundice or pancreatitis. Biliary surgery in patients with PDD and a dilated bile duct should include a biliary drainage procedure to prevent recurrence of pancreatobiliary disease.     

Effect of colloid volume expansion on glomerular barrier size-selectivity in humans

Colloid volume expansion magnifies proteinuria in subjects with the nephrotic syndrome. To elucidate this phenomenon, we performed differential solute clearances prior to and following infusion of hyperoncotic albumin in 21 nephrotic subjects and seven healthy controls. Urinary excretion rate and fractional clearance of albumin (radius = 36 A) and immunoglobulin G (radius = 55 A) increased significantly in nephrotic subjects. However, urinary albumin excretion rate was unchanged in controls. The fractional clearances of dextrans of broad size distribution (radii = 28 to 58 A) were markedly altered in both groups following albumin infusion. A heteroporous model which depicts the major portion of the glomerular capillary wall as an isoporous membrane (pore radius approximately 55 A) and the minor portion as a non-discriminatory shunt, revealed the latter to be much more prominent in nephrotic subjects than in controls, and to be enlarged further following albumin infusion. By contrast no increase in pore size of the non-shunt pathway occurred in either group. We infer that enhancement of a pre-existing defect of glomerular size-selectivity in nephrotic subjects accounts, in large part, for exaggerated proteinuria in the colloid volume-expanded state. Increases in glomerular perfusion rate and pressure associated with plasma hypervolemia may mediate this alteration in glomerular membrane-pore structure.     

Post-Traumatic Stress Disorder in Children: Controversies and Unresolved Issues

TOPIC: Questions regarding how severely traumatized children may meet diagnostic criteria for an accurate diagnosis of posttraumatic stress disorder (PTSD), the comorbidity of PTSD with many other psychiatric illnesses, and the possibility that PTSD is not a valid diagnostic formulation as it has been applied to children and adolescents demonstrate that the currently held concept of PTSD may not be operationally sound. PURPOSE: To explore recent empirical studies to demonstrate the current state of controversy and postulate future direction of the conceptual framework. SOURCES: Selected published literature. CONCLUSIONS: PTSD in children and adolescents, as it is popularly understood as a conceptual framework, is found to be undergoing a conceptual metamorphosis.