An evaluation of operator preference of diamond burs in coronal tooth preparation

Three postgraduate prosthodontic students served as clinicians/evaluators in a study rating their preferences for three different diamond cutting instruments from three manufacturers. Each evaluator prepared the axial walls of complete veneer crowns on extracted molar teeth and then ranked their preference of the instruments. To prepare nine teeth, each of the three instruments was used in random order and without knowledge of the specific manufacturer. The methodology for analyzing the evaluators' preferences and the results are discussed.     

Characterization of nephropathy induced by immunization with high molecular weight dextran

BACKGROUND: Injection of DEAE dextran into Lewis rats can produce proteinuria and has been reported as a model of IgA nephropathy. METHODS: Cationic diethyl aminoethyl (DEAE) dextran of molecular weight 500 kDa was injected into male Lewis rats. After a pre-immunization period of 3 weeks, the animals were divided into two groups: group 1 (n = 14) received daily i.v, injections of 3.5 mg of antigen, group 2 (n = 14) was injected with 1.5 mg three times per week for a total period of 6 weeks. I.v. treatment was initiated with gradually increasing doses of DEAE dextran in both groups for 1 week, after which the maintenance dose was reached. RESULTS: We observed the appearance of proteinuria in a nephrotic range after 5 weeks of i.v. injections in group 1 (urinary excretion: 332 +/- 83 mg/24 h, controls: 53 +/- 14 mg/24 h). In group 2, the proteinuria was almost equal to protein excretion of healthy rats of the same weight (67 +/- 20 mg/24 h). The serum and urine creatinine were normal. By light microscopy of kidney biopsies, the presence of focal and segmental proliferation of mesangial cells after 6 weeks of i.v. injections was identified. Immunohistochemistry revealed no deposition of IgA, IgM, IgG, or C3. Using anti-ED1 antibodies, there was no evidence of interstitial infiltration of monocytes/macrophages after 6 weeks of i.v. injections. Staining for proliferating cell nuclear antigen (PCNA) did not show the presence of proliferating cells either in glomeruli or in the interstitium. Staining with FITC-WGA lectin revealed focal and segmental loss of the negative charge in the capillary wall. By electron microscopy there was deposition of dextran in the basal membrane and segmental and focal damage of the podocyte foot processes. As the chemokine RANTES may be involved in glomerular injury, we examined the kidneys of proteinuric and non-proteinuric rats for the presence of RANTES. By indirect immunofluorescence only the proteinuric rats showed RANTES deposition in the mesangium. CONCLUSIONS: Injection of rats with DEAE dextran leads to dose-dependent proteinuria without deposition of immune complexes but with podocyte damage. This is associated with local expression of the chemokine RANTES which may play a role in proteinuria of glomerular disease.     

Management of ingested foreign bodies within the appendix: a case report with review of the literature

A case is reported of an elective appendectomy in a patient with known ingestion of a sharp foreign body. The metal drill bit was ingested unintentionally 3 months before presentation at our institution. Plain abdominal films demonstrated the foreign body in the right lower abdominal quadrant. Because the gold dental drill bit was sharp and thought to be lodged in the terminal ileum or cecum, an attempt was made to remove the object during colonoscopy. This attempt was unsuccessful because no drill bit could be detected in the colon or terminal ileum. A laparoscopic exploration was performed, and the foreign body was found to lie in the appendix, after bowel manipulation under fluoroscopic guidance and with direct laparoscopic visualization. A laparoscopic assisted appendectomy was performed. On pathologic examination the drill bit was embedded in the tip of the appendix with signs of intramucosal acute inflammation. Management and indication for surgery of foreign bodies in the appendix are discussed, and we review the related literature. This is the second reported case of a dental drill bit in the appendix causing appendicitis.     

Ex vivo culture of peripheral blood CD34+ cells: effects of hematopoietic growth factors on production of neutrophilic precursors

A major potential application for ex vivo culture of hematopoietic progenitor cells is the treatment of cytopenia following high-dose chemotherapy and hematopoietic transplantation. We have previously postulated that infusion of a sufficient number of neutrophil postprogenitor cells generated by ex vivo culture of CD34+ cells may be able to abrogate neutropenia. In this article, we describe further development of an efficient stromal-free, cytokine-dependent, static culture system for generation of these cells. Our previous studies indicated that maximal production of nucleated cells and myeloid progenitor cells from PB CD34+ cells occurred with multiple hematopoietic growth factor (HGF), notably the 6-HGF combination of interleukin (IL)-1, IL-3, IL-6, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage-CSF (GM-CSF), and stem cell factor (SCF). In the present study, we determine the contribution of each of these 6 HGF in generation of neutrophilic precursors. SCF, G-CSF, and IL-3 were found to be the most important HGF for production of neutrophilic cells. The 4-HGF combination of IL-3, IL-6, G-CSF, and SCF was optimized by performing dose-response experiments and shown to be as potent as 6 HGF for production of nascent CFU-GM and neutrophilic precursors.