The Abrasive Effect of a Porcelain and a Nickel–Chromium Alloy on the Wear of Human Enamel and the Influence of a Carbonated Beverage on the Rate of Wear

Purpose: This study was conducted to determine the abrasive effect of a porcelain and an Ni–Cr alloy on the wear of human enamel, and the influence of a carbonated beverage on the rate of wear. Materials and Methods: Tooth specimens were prepared by embedding 48 freshly extracted mandibular first premolars in acrylic. Twenty‐four of these specimens were abraded against Ni–Cr, and the remaining 24 against porcelain in artificial saliva and carbonated beverage media, respectively (n = 12), on a specially designed abrasive testing machine at a constant load of 40 N with 6 mm amplitude for 15,000 cycles. The cusp heights of the tooth specimens were measured both before and after abrasion using a profile projector. The abraded cast specimens were subjected to profilometry for computing the surface roughness; the abrading media was subjected to atomic absorption spectrophotometry for analyzing Ni and Cr ion levels. Data obtained were statistically analyzed. Results: Porcelain specimens in a medium of carbonated beverage caused the highest wear of tooth specimens. The lowest wear of tooth specimens was Ni–Cr specimens in artificial saliva medium. Carbonated beverage caused significantly higher wear of tooth specimens when abraded against Ni–Cr and porcelain specimens than did artificial saliva. The mean quantitative surface roughness of porcelain specimens was significantly higher than that of Ni–Cr specimens, irrespective of the medium in which abrasion testing was conducted. There was no statistically significant difference between the concentrations of Ni ions released in artificial saliva and carbonated beverage media. Also, there was no statistically significant difference between the concentrations of Cr ions released in artificial saliva and carbonated beverage media. Conclusions: The wear of human enamel was significantly higher in the presence of carbonated beverage than artificial saliva and against porcelain when compared with Ni–Cr. The surface roughness of porcelain in the presence of carbonated beverage was found to be highest, and the release of Ni and Cr was not affected by carbonated beverage.     

Robot-assisted pancreatic surgery: a systematic review of the literature

Background

To potentially improve outcomes in pancreatic resection, robot-assisted pancreatic surgery has been introduced. This technique has possible advantages over laparoscopic surgery, such as its affordance of three-dimensional vision and increased freedom of movement of instruments. A systematic review was performed to assess the safety and feasibility of robot-assisted pancreatic surgery.

Methods

The literature published up to 30 September 2011 was systematically reviewed, with no restrictions on publication date. Studies reporting on over five patients were included. Animal studies, studies not reporting morbidity and mortality, review articles and conference abstracts were excluded. Data were extracted and weighted means were calculated.

Results

A total of 499 studies were screened, after which eight cohort studies reporting on a total of 251 patients undergoing robot-assisted pancreatic surgery were retained for analysis. Weighted mean operation time was 404 ± 102 min (510 ± 107 min for pancreatoduodenectomy only). The rate of conversion was 11.0% (16.4% for pancreatoduodenectomy only). Overall morbidity was 30.7% (n = 77), most frequently involving pancreatic fistulae (n = 46). Mortality was 1.6%. Negative surgical margins were obtained in 92.9% of patients. The rate of spleen preservation in distal pancreatectomy was 87.1%.

Conclusions

Robot-assisted pancreatic surgery seems to be safe and feasible in selected patients and, in left-sided resections, may increase the rate of spleen preservation. Randomized studies should compare the respective outcomes of robot-assisted, laparoscopic and open pancreatic surgery.     

Impact of laparoscopic right hemicolectomy for colon cancer

INTRODUCTION

This study specifically examined right colonic cancer resection, a common operation for colorectal surgeons starting laparoscopic resection, to assess the impact of commencing laparoscopy.

PATIENTS AND METHODS

A total of 56 patients undergoing open (n = 34) and attempted laparoscopic (n = 22) elective right hemicolectomy for colorectal cancer between November 2003 and March 2007 were compared. Postoperative stay was the primary outcome. Secondary outcomes included analgesic requirements, bowel recovery, morbidity and mortality. Frequency of laparoscopic versus open surgery over time was also examined.

RESULTS

Resections attempted laparoscopically increased from 9.1% to 75% in the first and last quarters of the study period, respectively (P = 0.0002). Uptake of ‘enhanced recovery’ was mainly in the laparoscopic group. Conversion was required in two of 22 patients. Attempted laparoscopic cases had a shorter median postoperative stay (6 vs 10 days; P < 0.0001), duration of parenteral or epidural analgesia (48 vs 72 h; P < 0.0001) and time to first bowel action (3 vs 4 days; P = 0.001) compared with open cases. Demography, tumour characteristics, morbidity and mortality were comparable between groups. Multivariate analysis identified decreased age, attempted laparoscopic surgery, use of enhanced recovery and absence of complications as independently shortening postoperative stay.

CONCLUSIONS

Advantages of laparoscopic surgery and enhanced recovery, even early in a surgeon''s experience, suggest this is the preferred mode for elective right colon cancer resection.     

Preoperative ejection fraction as a predictor of survival after coronary artery bypass grafting: comparison with a matched general population

Background  

Preoperative left ventricular dysfunction is an established risk factor for early and late mortality after revascularization. This retrospective analysis demonstrates the effects of preoperative ejection fraction on the short-term and long-term survival of patients after coronary artery bypass grafting.     

Cyclooxygenase-2 polymorphisms and the risk of esophageal adeno- or squamous cell carcinoma

AIM： TO determine whether -1195 A→G and/or -765 G→C polymorphisms in Cyclooxygenase-2 CCOX-2） may have a risk modifying effect on the development of esophageal carcinoma in a Dutch Caucasian population. METHODS： Two study groups were recruited, 252 patients with esophageal carcinoma and 240 healthy controls, matched for race, age, gender and recruiting area. DNA was isolated from whole blood and used for genotyping. PCR products were digested with restriction enzymes and products were analyzed by agarose gel electrophoresis. Odds ratios （OR） and 95% confidence intervals （CI） were estimated. RESULTS： The distribution of the -1195A→G polymorphism was significantly different in esophageal cancer patients compared to controls. The -1195 GG genotype resulted in a higher risk of developing esophageal adenocarcinoma （OR = 3.85, 95% CI： 1.45-10.3） compared with the -1195AA genotype as a reference. The -765 G→C genotype distribution was not different between the two groups. The GG/ GG haplotype was present more often in esophageal adenocarcinoma patients than in controls （OR = 3.45, 95% CI： 1.24-9.58; with AG/AG as a reference）. The same trends were observed in patients with squamous cell carcinomas, however, the results did not reach statistical significance. CONCLUSION： Presence of the COX-2 -1195 GG genotype and of the GG/GG haplotype may result in a higher risk of developing esophageal carcinoma.     

COX-2 polymorphisms -765G →C and -1195A→G and colorectal cancer risk

AIM： TO determine the possible modulating effect of the COX-2 polymorphisms, -765G→C and -1195A→G, on the risk of colorectal cancer （CRC） in a Dutch population. METHODS： This case-control study includes 326 patients with CRC and 369 age- and gender-matched controls. Genotypes of the COX-2 polymorphisms -7dEG→C and -1195A→G were determined by polymerase chain reaction-based restriction fragment length polymorphism. COX-2 genotypes and haplotypes were analyzed and odds ratios with 95% confidence intervals were estimated by logistic regression. RESULTS： The -765GG genotype was associated with an increased risk of developing CRC （OR, 1.45; 95% CI, 1.03-2.04）. No significant difference was observed in the genotype distribution of the -1195A→G polymorphism between patients and controls. The GG/AC haplotype was present significantly less often in patients than in controls （OR 0.44; 95% CI, 0.22-0.85）. When the AC, AG and GG haplotypes were investigated separately, the AC haplotype showed a tendency to be less frequent in patients than in controls （OR（AG/AC） 0.78; 95% CI, 0.57-1.06）. CONCLUSION： The -765GG genotype is associated with an increased risk of developing CRC and the G6/ AC haplotype seems to protect against CRC. These findings suggest a modulating role for the COX-2 polymorphisms -765G→C and -1195A→G in the development of CRC in a Dutch population.     

Using oriental medicine symptom patterns to identify prostatic hyperplasia patients who may benefit from oriental therapies

Li S, Lu A, Wang Y. Symptomatic comparison in efficacy on patients with benign prostatic hyperplasia treated with two therapeutic approaches. Comp Ther Med 2010; 18: 21–7.