Relevance of Toll-like receptor-4 polymorphisms in renal transplantation

BACKGROUND: Polymorphisms in Toll-like receptor-4 (TLR4) have been reported to be associated with a blunted immune response to microbial pathogens, as well as a decreased risk of atherosclerosis in the general population. We assessed the impact of the two TLR4 variants on the risk of severe infection, the incidence of acute rejection, and the occurrence of atherosclerotic complications in renal transplant recipients (RTR). METHODS: TLR-4 polymorphisms were assessed in a cohort of 238 RTR. Post-transplant atherosclerotic events, acute rejection, severe bacterial infection, cytomegalovirus (CMV) disease, and opportunistic infections were evaluated as outcomes. RESULTS: The patients were followed for a mean duration of 95 +/- 29 months after transplant. TLR4 polymorphism was observed in 27 (11.3%) RTR. Subjects with TLR4 polymorphisms were less likely to experience post-transplant atherosclerotic events (RR 0.44; 95% CI 0.21 to 0.93; P= 0.02) and acute rejection (RR 0.41; 95% CI 0.30 to 0.83; P= 0.01), but presented severe bacterial infections (RR 1.33; 95% CI 1.12 to 1.67; P= 0.01) and opportunistic infections (RR 3.03; 95% CI 1.72 to 8.29; P= 0.008) more frequently. TLR4 polymorphism was marginally associated with CMV disease (RR 1.47; 95% CI 0.95 to 2.64; P= 0.08). CONCLUSION: RTR with TLR4 polymorphism present a lower risk of post-transplant atherosclerotic events and acute allograft rejection, but experience severe infectious episodes more frequently. This subset of RTR may benefit from a less potent immunosuppression regimen, along with increased preventive measures against infectious agents.     

Assessment of two thoracolumbar fracture classification systems as used by multiple surgeons

BACKGROUND: The reproducibility and repeatability of modern systems for classification of thoracolumbar injuries have not been sufficiently studied. We assessed the interobserver and intraobserver reproducibility of the AO (Arbeitsgemeinschaft für Osteosynthesefragen) classification and compared it with that of the Denis classification. Our purpose was to determine whether the newer, AO system had better reproducibility than the older, Denis classification. METHODS: Anteroposterior and lateral radiographs and computerized tomography scans (axial images and sagittal reconstructions) of thirty-one acute traumatic fractures of the thoracolumbar spine were presented to nineteen observers, all trained spine surgeons, who classified the fractures according to both the AO and the Denis classification systems. Three months later, the images of the thirty-one fractures were scrambled into a different order, and the observers repeated the classification. The Cohen kappa (kappa) test was used to determine interobserver and intraobserver agreement, which was measured with regard to the three basic classifications in the AO system (types A, B, and C) as well as the nine subtypes of that system. We also measured the agreement with regard to the four basic types in the Denis classification (compression, burst, seat-belt, and fracture-dislocation) and with regard to the sixteen subtypes of that system. RESULTS: The AO classification was fairly reproducible, with an average kappa of 0.475 (range, 0.389 to 0.598) for the agreement regarding the assignment of the three types and an average kappa of 0.537 for the agreement regarding the nine subtypes. The average kappa for the agreement regarding the assignment of the four Denis fracture types was 0.606 (range, 0.395 to 0.702), and it was 0.173 for agreement regarding the sixteen subtypes. The intraobserver agreement (repeatability) was 82% and 79% for the AO and Denis types, respectively, and 67% and 56%, for the AO and Denis subtypes, respectively. CONCLUSIONS: Both the Denis and the AO system for the classification of spine fractures had only moderate reliability and repeatability. The tendency for well-trained spine surgeons to classify the same fracture differently on repeat testing is a matter of some concern.     

Renin-angiotensin system polymorphisms and renal graft function in renal transplant recipients

OBJECTIVE: To analyze the role of 3 polymorphisms of the renin-angiotensin system (RAS) in renal transplant recipients (RTRs) and correlate them with graft function. METHODS: The present study was performed in the Drug Applied Research Center, Tabriz Medical University, Tabriz, Iran from September 2003 to December 2005 on 108 RTRs (66 males and 42 females, with a mean age of 37.34 +/- 4.97 years) with stable allograft function (creatinine < or =2.2 mg/dl). Following the DNA extraction from the blood leukocytes, the genotypes of the angiotensin converting enzyme (ACE I/D), angiotensinogen (ANG M235T), and angiotensin II type 1 receptor (ATR1 A1166C) were determined by polymerase chain reaction. The magnitude of clearance of creatinine (ClCr) in the setting of each of the above RAS polymorphisms was determined. The ClCr was measured by modification of diet in renal disease formula. Values were expressed as mean +/- SD; p< or =0.05 was considered to indicate statistical significance. RESULTS: There was no association of each genotype of the RAS alone with ClCr, serum urea, cyclosporine through level and the degree of urinary protein excretion rate. However, patients with the DD genotype of angiotensin converting enzyme + CC genotype of angiotensin II type I receptor polymorphisms had lower ClCr (p=0.05) and a higher urinary protein excretion rate (p=0.03). Other combination genotypes of RAS had no effect on allograft function. Interestingly, the percent of hypertensive patients in the C allele (70%) was more than the A allele (30%) of ATR1 polymorphism (p=0.04). CONCLUSION: Although none of the single gene polymorphisms of the RAS affected renal allograft function, combinations of these genotypes were associated with the outcome of allograft function.     

Pre-etching vs. grinding in promotion of adhesion to intact enamel using self-etch adhesives

This study was aimed to determine the effectiveness of grinding and pre-etching in promotion of adhesion to human intact enamel using the self-etch adhesive (SEA) Adper Easy Bond (3M ESPE). Etch-and-rinse adhesive Adper Single Bond (3M ESPE) served as control. Composite cylinders (AP-X Kuraray) were built and after 24 h micro-shear bond strengths (MSBS) were measured. Bonding interfaces were evaluated under scanning electron microscope (SEM). For evaluation of average roughness (Ra) and morphological analysis, treated enamel surfaces were observed under SEM and confocal laser scanning microscope (CLSM) with 3D surface profiling. Highest bond strengths were obtained by pre-etching and grinding showed a less significant role. Phosphoric acid (PA) etching compare to grinding created significantly rougher surface (Ra: 0.72 and 0.43 μm respectively). Therefore, this study recommends pre-etching the intact enamel prior to application of the adhesive instead of grinding.     

A Biomechanical Foot-Worn Device Improves Total Knee Arthroplasty Outcomes

Background

Biomechanics after total knee arthroplasty (TKA) often remain abnormal and may lead to prolonged postoperative recovery. The purpose of this study is to assess a biomechanical therapy after TKA.

A successful anticoagulation protocol for the first HeartMate II implantation in the United States

Bleeding and thrombus formation are common problems with life-threatening implications in patients receiving a left ventricular assist device. We describe the anticoagulation protocol for the 1st patient in the United States to undergo successful implantation of the HeartMate II left ventricular assist system.