Shaping ability of RaCe rotary nickel-titanium instruments in simulated root canals

This study assessed the shaping ability of RaCe rotary nickel-titanium instruments in simulated root canals. Forty simulated root canals consisting of four different shapes were prepared with RaCe rotary nickel-titanium instruments in a crowndown approach. Preoperative images were taken at the outset and postoperative images at various stages of preparation including at the conclusion of the shaping procedure. The combined images enabled assessment of aberrations and resin removal at various positions along the canal length. Overall, mean preparation time to size 40, .02 taper was 1.36 min. Thirty-three canals (83%) maintained the working length, three instruments deformed and no zips, perforations, or ledges were created. Under the conditions of this study RaCe rotary nickel-titanium instruments prepared simulated canals rapidly and successfully, with little change in working length and with few aberrations or instrument deformities.     

Influence of pancreas transplantation alone on native renal function

Pancreas transplantation alone (PTA) has become an accepted treatment of nonuremic diabetic patients, when the risks of secondary complications of diabetes mellitus are greater than those of the surgical procedure and the posttransplant immunosuppression. As a decrease in native renal function is expected, we followed this parameter among patients who underwent PTA. From January 1997 through January 2005, we performed 69 PTA in 66 patients. All patients showed glucose hyperlability with hypoglycemic unawareness, or two or more diabetic complications as well as creatinine clearance (CrCl) > or = 45 mL/min. Immunosuppression was based on tacrolimus, mycophenolate mofetil and prednisone. Twenty-four hour CrCl were performed after all successful PTA. We divided patients in two groups according to the pretransplant CrCl: group 1, CrCl < or = 70 mL/min (n = 20) and group 2, CrCl > 70 mL/min (n = 25). The data were analyzed using Student's t-test (P < or = .05 was considered significant). Twenty-one patients were excluded from the analysis because of death (n = 5) or graft loss (n = 8) during the first year or follow-up shorter than 1 year (n = 8). The mean value of CrCl decreased 28.8% (85.0 +/- 31 versus 60.5 +/- 36 mL/min; P < .001). There was also a 39.3% reduction among group 1 subjects (P = .003), including 10 who displayed CrCl < or = 30 mL/min. There was also a 24.4% reduction among group 2 (P = .008), but no patient developed end-stage renal disease. In conclusion, native renal function decreased significantly after PTA, but was well tolerated among patients with CrCl > 70 mL/min. Patients with CrCl < 70 mL/min show a significant risk of worsened renal function.     

Cephalic pancreaticoduodenectomy with mesentericoportal venous reconstruction. Technical features

Cephalic pancreaticoduodenectomy (CPD) with mesentericoportal venous resection increases the resectability rate of pancreatic tumors. When performed in selected patients and by experienced surgical teams, this technique shows the same long-term rates of morbidity, mortality and survival as CPD without vascular resection, provided that negative surgical margins are obtained. This procedure is contraindicated by complete thrombosis of the portal or superior mesenteric veins, invasion of the superior mesenteric artery or celiac trunk, and distant or periaortic lymph node involvement. Venous reconstruction can be performed through lateral suture, termino-terminal anastomosis, or by graft placement. We believe that intercalation of the autologous internal jugular vein facilitates resection and minimizes phenomena of venous stasis. We present a case of adenocarcinoma of the pancreatic head infiltrating the superior mesenteric-portal vein confluence that underwent surgery in our hospital. CPD with mesentericoportal venous resection and reconstruction using autologous internal jugular vein were performed. The most important technical features are discussed.     

Polyacylated oligosaccharides from medicinal Mexican morning glory species as antibacterials and inhibitors of multidrug resistance in Staphylococcus aureus

Twenty-two convolvulaceous oligosaccharides selected from the tricolorin (1-7), scammonin (8, 9), and orizabin (10-22) series were evaluated for activity against a panel of Staphylococcus aureus strains possessing or lacking specific efflux pumps. The minimum inhibitory concentrations (MIC values) for most of the amphipatic compounds ranged from 4 to 32 microg/mL against XU-212 (possessing the TetK multidrug efflux pump) and SA-1199B (overexpressing the NorA multidrug efflux pump), compared with 64 and 0.25 microg/mL, respectively, for tetracycline. This activity was shown to be bactericidal. Two microbiologically inactive members of the orizabin series (10, 20) increased norfloxacin susceptibility of strain SA-1199B. At low concentrations, compound 10 was a more potent inhibitor of multidrug pump-mediated EtBr efflux than reserpine. The wide range of antimicrobial activity displayed by these compounds is an example of synergy between related components occurring in the same medicinal crude drug extract, i.e., microbiologically inactive components disabling a resistance mechanism, potentiating the antibiotic properties of the active substances. These results provide an insight into the antimicrobial potential of these complex macrocyclic lactones and open the possibility of using these compounds as starting points for the development of potent inhibitors of S. aureus multidrug efflux pumps.     

Time course study of oxidative and nitrosative stress and antioxidant enzymes in K2Cr2O7-induced nephrotoxicity

Background

It has been established that hypothyroidism protects rats against renal ischemia and reperfusion (IR) oxidative damage. However, it is not clear if hypothyroidism is able to prevent protein tyrosine nitration, an index of nitrosative stress, induced by IR or if antioxidant enzymes have involved in this protective effect. In this work it was explored if hypothyroidism is able to prevent the increase in nitrosative and oxidative stress induced by IR. In addition the activity of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase was studied. Control and thyroidectomized (HTX) rats were studied 24 h of reperfusion after 60 min ischemia.

Methods

Male Wistar rats weighing 380 ± 22 g were subjected to surgical thyroidectomy. Rats were studied 15 days after surgery. Euthyroid sham-operated rats were used as controls (CT). Both groups of rats underwent a right kidney nephrectomy and suffered a 60 min left renal ischemia with 24 h of reperfusion. Rats were divided in four groups: CT, HTX, IR and HTX+IR. Rats were sacrificed and samples of plasma and kidney were obtained. Blood urea nitrogen (BUN) and creatinine were measured in blood plasma. Kidney damage was evaluated by histological analysis. Oxidative stress was measured by immunohistochemical localization of protein carbonyls and 4-hydroxy-2-nonenal modified proteins. The protein carbonyl content was measured using antibodies against dinitrophenol (DNP)-modified proteins. Nitrosative stress was measured by immunohistochemical analysis of 3-nitrotyrosine modified proteins. The activity of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase was measured by spectrophotometric methods. Multiple comparisons were performed with ANOVA followed by Bonferroni t test.

Results

The histological damage and the rise in plasma creatinine and BUN induced by IR were significantly lower in HTX+IR group. The increase in protein carbonyls and in 3-nitrotyrosine and 4-hydroxy-2-nonenal modified proteins was prevented in HTX+IR group. IR-induced decrease in renal antioxidant enzymes was essentially not prevented by HTX in HTX+IR group.

Conclusion

Hypothyroidism was able to prevent not only oxidative but also nitrosative stress induced by IR. In addition, the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase seem not to play a protective role in this experimental model.     

Halogenated helianane derivatives from the sponge Spirastrella hartmani

Two new halogenated derivatives (1 and 2) of helianane (3) were isolated from the 2-propanol extract of the sponge Spirastrella hartmani. The structures of the new derivatives were determined on the basis of detailed spectroscopic analysis, including (+)-HREIMS and 1D and 2D NMR. Compound 1 showed in vitro cytotoxicity against the human tumor cell lines A549, HT29, and MDA-MB-231.