Radiofrequency and laser ablation of spinal lesions.

Radiofrequency current and laser energy can be delivered locally through electrode-needle or optical fiber inserted in the tissue and allows local ablation of tissues, up to a volume of 4 to 5 cm in diameter with one application or vaporizes tissue. Tumor ablation guided with medical imaging proved a high local efficacy over 90% for tumors less than 25 mm in the liver, lung, and kidney. The spinal applications of the thermal energy of RF and laser are reported in this paper. First, the tumor ablation is reviewed with malignant and benign tumors. In malignant tumors, radiofrequency is very efficient in local tumor control and in pain management. The second part of this paper is devoted to disk diseases where laser and RF techniques increase their applications. The technique, indications and results of these techniques are reported and illustrated.     

Investigating the performance of four specific types of material grafts and their effects on hemodynamic patterns as well as on von Mises stresses in a grafted three-layer aortic model using fluid-structure interaction analysis

One of the important parts of the cardiac system is aorta which is the fundamental channel and supply of oxygenated blood in the body. Diseases of the aorta represent critical cardiovascular bleakness and mortality around the world. This study aims at investigation of hemodynamic parameters in a two-dimensional axisymmetric model of three-layer grafted aorta using fluid–structure interaction (FSI). It assumes that a damaged part of aorta, which may happen as a result of some diseases like aneurysm, dissection and post-stenotic dilatation, is replaced with a biomaterial graft. Four types of grafts materials so-called Polyurethane, Silicone rubber, Polytetrafluoroethylene (PTFE) and Dacron are considered in the present study. The assumption of linear elastic and isotropic material is set for the both aorta's wall and aforementioned grafts. Blood is considered as an incompressible and Newtonian fluid. The results indicate higher displacement in Polyurethane and silicone rubber in comparison with other two. Furthermore, results reveal that blood flow velocity has slightly higher values in PTFE and Dacron grafted models compared to Polyurethane and Silicone rubber ones. Even though there are some differences in hemodynamic patterns in these grafted models, they are not considerable as much as von Mises stresses across the graft-aorta intersections are. This study shows that the types of material grafts play an important role in the amount of stresses particularly at intersections of aorta and graft.     

Tumor antigen discovery through translation of the cancer genome

Cancer cells harbor unique mutations that theoretically create corresponding unique tumor-specific antigens. This class of mutated antigens represents an attractive target for cancer immunotherapy, but their identification has been cumbersome. By combining cancer genome sequencing with computational analysis of MHC binding, it is possible to predict and rank all of the possible mutated tumor antigens. This form of antigen screen is being combined with high throughput methods to measure the immune response to each candidate mutated antigen. Using these techniques, it is possible to systematically test each mutated tumor antigens for an associated immune response. Only a small fraction of the putative mutated antigens tested in this manner have been found to elicit an immune response, yet these responses appear to be both robust and durable. It is becoming increasingly clear that these mutated tumor antigens are an important target in the antitumor response. Studies incorporating this approach promise to improve our understanding of the inherent immunogenicity of individual cancers, potentially providing an explanation for the varying clinical responses to novel immunotherapeutic agents.     

Predictors of venous obstruction following pacemaker or implantable cardioverter-defibrillator implantation: a contrast venographic study on 100 patients admitted for generator change, lead revision, or device upgrade.

AIM: Venous obstruction following transvenous device implantation rarely cause immediate clinical problems. When lead revision or device upgrade is indicated, venous obstruction become a significant challenge. The aim of this study was to determine the predictors of venous obstruction after transvenous device implantation, and to asess likely effects of antiplatelet/anticoagulant drugs in preventing venous thrombosis. METHODS AND RESULTS: Between March 2005 and July 2006, contrast venography was performed in 100 patients who were candidates for generator change, lead revision, or device upgrade. Vessel patency was graded as either completely obstructed, partially obstructed (>70%), or patent. The incidence of venous obstruction was 26%, with 9% of patients having total obstruction and 17% of patients exhibiting partial obstruction. No statistically significant differences between obstructed and non-obstructed patients were seen for age, sex, indication for device implantation, atrial fibrillation, cardiothoracic ratio, insulation material, operative technique, device type, and manufacturer (all Ps > 0.05). In a univariate analysis, multiple leads (P = 0.033), and presence of dilated cardiomyopathy (P = 0.036) were associated with higher risk of venous obstruction, whereas anticoagulant/antiplatelet therapy (P = 0.047) significantly reduced incidence of venous obstruction. Multivariate logistic regression analysis showed that only number of the leads (P = 0.039, OR: 2.22, and 95% CI: 1.03-4.76) and antiplatelet/anticoagulant therapy (P = 0.044, OR: 2.79, and 95% CI: 0.98-7.96) were predictors of venous obstruction. CONCLUSION: Total or partial obstruction of the access veins occurs relatively frequently after pacemaker or ICD implantation. Multiple pacing or ICD leads are associated with an increased risk of venous obstruction, whereas antiplatelet/anticoagulant therapy appears to have a preventive effect on development of access vein thrombosis.     

Optimal β-blocker for prevention of atrial fibrillation after on-pump coronary artery bypass graft surgery: Carvedilol versus metoprolol

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia after coronary artery bypass graft (CABG) surgery. It has been shown that prophylactic oral beta-blocker administration reduces the incidence of post-CABG AF. However, the optimal beta-blocker has not been identified. OBJECTIVE: This study sought to determine whether oral carvedilol (with its unique anti-inflammatory and antioxidant properties) is more effective than oral metoprolol for prevention of AF after CABG surgery. METHODS: Between April 2006 and December 2006, 120 patients (63 men, mean age 61 +/- 9.4 years) who were scheduled to undergo their first on-pump CABG were enrolled in this study. The patients were randomized in a prospective 1:1 manner to receive either oral carvedilol (n = 60) or oral metoprolol (n = 60). The end point of the study was the occurrence of the new-onset AF during the first 5 days after CABG. RESULTS: AF occurred in 29 of 120 patients (24.0%). The incidence of postoperative AF was 15.0% (9 of 60) in the carvedilol group and 33% (20 of 60) in the metoprolol group (P = .022). The carvedilol group was treated with mean daily dose of 46 +/- 9 mg and metoprolol group with mean daily dose of 93 +/- 11 mg. There were no differences between the study groups regarding any known preoperative, perioperative, or postoperative characteristics (all values were P >.05). No significant adverse effect was observed in either group. CONCLUSION: This prospective study suggested that oral carvedilol is more effective than oral metoprolol in the prevention of AF after on-pump CABG. It is well tolerated when started before and continued after the surgery. However, further prospective studies are needed to clarify this issue.     

Evaluation of humoral immune function in patients with bronchiectasis

Bronchiectasis is a chronic debilitating condition characterized by abnormal dilated thick-walled bronchi. To investigate humoral immune function in bronchiectatic patients, this study was performed. Forty patients with established diagnosis of bronchiectasis, who were referred from two tertiary care pulmonology centers in Tehran, were investigated in this study. Immunoglobulin isotypes concentrations and IgG-subclasses were measured by nephelometry and enzyme-linked immunosorbent assay (ELISA) methods, respectively. All patients received unconjugated pneumococcal vaccine, and blood samples were taken before and 21 days after vaccination. Specific antibodies against whole pneumococcal antigens were measured using the ELISA method. Fifteen (37.5%) out of 40 patients were diagnosed to have defects in antibody mediated immunity including 5 (12.5%) patients with immunoglobulin class deficiency (2 with common variable immunodeficiency and 3 with IgA deficiency), 3 (7.5%) with IgG subclass deficiency and 7 (17.5%) patients had Specific antibody deficiency (SAD) against polysaccharide antigen despite normal levels of serum immunoglobulins and IgG subclasses. Our study along with several other studies confirmed that all patients with bronchiectasis should undergo thorough immunological evaluation in order to identify the presence of the underlying immunologic defect. This evaluation should include serum immunoglobulins, IgG subclasses concentrations and also determination of serum antibodies against pneumococcal antigens. Early diagnosis and appropriate treatment will prevent the subsequent complications and improve quality of life of affected individuals.     

The Efficacy of an Herbal Medicine, Carmint, on the Relief of Abdominal Pain and Bloating in Patients with Irritable Bowel Syndrome: A Pilot Study

Carmint contains total extracts of Melissa officinalis, Mentha spicata, and Coriandrum sativum, which have antispasmodic, carminative, and sedative effects. As abdominal pain/discomfort and bloating are commonly observed in patients with irritable bowel syndrome, we decided to evaluate the effectiveness of Carmint in relieving these symptoms in irritable bowel syndrome patients. We randomly assigned 32 irritable bowel syndrome patients to receive either Carmint or placebo, plus Loperamide or psyllium (based on their predominant bowel function), for 8 weeks. T-test analysis of the results showed that the severity and frequency of abdominal pain/discomfort were significantly lower in the Carmint group than the placebo group at the end of the treatment (P=0.016 and P=0.001, respectively), as were the severity and frequency of bloating (P=0.02 and P=0.002, respectively). This pilot study suggests that Carmint plus loperamide or Carmint plus psyllium (depending on the irritable bowel syndrome subtype) might be effective in these patients.     

Detection of hepatitis B virus variants in HBV monoinfected and HBV/HIV coinfected Iranian patients under lamivudine treatment

Chronic hepatitis B affects nearly 10% of HIV-infected patients. Hepatitis B virus (HBV) infection is a dynamic disease and coinfection with HIV impacts directly on the outcome of HBV infection, considerably complicating its natural history, diagnosis, and management. The aim of this study was to compare two cohorts of HBV monoinfected and HBV/HIV coinfected Iranian patients undergoing long-term lamivudine therapy from the clinical and virological aspects, as well as the frequency of detected mutations in HBV genome. To this end, HBV Pol/S regions from 72 patients were PCR-amplified and directly sequenced. Phylogenetic analysis indicated a 40-times higher risk of coinfection with ayw3 subtype of HBV genotype D rather than ayw2 subtype [P<0.001, odd: 40.66, CI: 95 % (4.69-352.23)]. While no resistance mutation was detected in HBV/HIV coinfected cohort, LAM-resistance mutations (rtM204I/V in YMDD and rtL180M in FLLA polymerase motifs) were identified in 30% (9 out of 30) and 16.66% (5 out of 30) of HBV monoinfected patients (P<0.05). Moreover, several mutations (sP105A, sI110S/L, sS136Y and sP127T/L) with significant differences in the frequency were identified in the S region of both cohorts. Finally, this study found strong correlation between the type of infection (mono or coinfection) and characteristics like patient gender, ALT levels, HBV-DNA levels and HBV subtypes. These results pointed to the importance of determination of HBV variants in the management of patients and suggested that in contrary to HBV monoinfections, LAM may be still an appropriate drug for the treatment of HBV in HBV/HIV coinfected patients; however, further studies to clarify the role of HIV in HBV LAM-resistance mutations are required.