Novel thoracoscopic approach to posterior mediastinal goiters: report of two cases

Trans-cervical resection of posterior mediastinal goiters is usually very difficult, requiring a high thoracotomy. Until recently, using conventional video-assisted thoracoscopic surgery to resect such tumors has been technically difficult and unsafe. By virtue of 3 dimensional visualization, greater dexterity, and more accurate dissection, the Da Vinci robot, for the first time, enables a completely minimally invasive approach to the posterior superior mediastinum.     

Antigenotoxic role of Centella asiatica L. extract against cyproterone acetate induced genotoxic damage in cultured human lymphocytes.

The majority of the Indian population use traditional natural preparations derived from plant material for the treatment of various diseases, and for that reason it becomes necessary to assess the mutagenic potential or modulating action of plants extract when associated with other substances. The genotoxicity testing provides human a risk assessment. Earlier in vitro and in vivo studies reveal that the plant extracts from various parts of the plant play a modulating role in xenobiotic effects. Identification and characterization of some active principles may lead to the development of the strategies to reduce the risk for developing cancer in humans. Cyproterone acetate (CPA), a synthetic progestin is not only a genotoxic agent but also a tumor initiating agent. It is used in oral contraceptives formulations and also in the treatment of various sexual and metabolic disorders. In this context, the antigenotoxic effect of Centella asiatica L. extract was studied against the genotoxic effect induced by CPA on human lymphocytes using chromosomal aberrations and sister chromatid exchanges as parameters. The treatment of the two doses of CPA, i.e. 20 and 30 microM was given along with the C. asiatica extract at the dosages of 1.075 x 10(-4), 2.125 x 10(-4), 3.15 x 10(-4) and 4.17 x 0(-4)g/ml of culture medium. A clear dose dependent decrease in the genotoxic damage of CPA was observed, suggesting a protective role of C. asiatica extract during CPA therapy. The results of the present study suggest that the plant extract per se do not have genotoxic potential, but can modulate the genotoxicity of CPA on human lymphocytes in vitro.     

Acceptable recipient outcomes with the use of hearts from donors with hepatitis-B core antibodies.

BACKGROUND: The shortage of available donors limits cardiac transplantation. Use of hearts from patients with hepatitis-B core antibodies could expand the donor pool but are usually avoided because of concern about virus transmission. We conducted a retrospective review to determine the safety of transplanting hearts from donors with hepatitis-B core antibodies. METHODS: We reviewed donor and recipient charts for patients who underwent transplantation at our center between January 1, 1997, and December 1, 2002. RESULTS: A total of 541 heart transplantations were performed in this time period. Thirty-three patients (aged 47.5 +/- 18.8 years) received hearts from core-antibody-positive donors (aged 37.7 +/- 10.8 years). Of these, 5 patients received prophylactic antibiotic treatment with lamivudine after transplantation. Only 1 patient (baseline surface-antigen-negative and without prophylaxis) experienced donor-transmitted hepatitis B infection 10 months after transplantation that was treated with lamivudine. Two patients (baseline surface-antibody-negative) had hepatitis B seroconversion, becoming surface-antibody positive without evidence of infection. None of the 5 patients who received prophylaxis with lamivudine had donor-transmitted hepatitis, and only 1 lamivudine-treated patient had surface antibodies. Post-transplant survival in this small cohort was similar to that for all patients who underwent transplantation at our center during this time period. CONCLUSIONS: Transplantation of hearts from donors with hepatitis-B core antibodies is associated with a small viral-transmission risk, with or without post-transplant, anti-viral prophylaxis. Use of these donor hearts should be considered safe and may help to augment the available donor pool.     

Maximal thymectomy in children with myasthenia gravis.

OBJECTIVES: We performed this study to evaluate the benefit of thymectomy in children with myasthenia gravis (MG). METHODS: Over a period of 15 years from 1986 to 2001, we collected data on 30 children with MG and retrospectively reviewed the outcome of maximal thymectomy. RESULTS: There were 23 females and seven males with a mean age of 13.2 years (range 4-16). The mean duration of the disease was 19.3 months (range 2-144). According to Osserman classification, there were 14 children in class II; 12 in class III; and four children in class IV. One child in class IV required postoperative ventilation and one was re-explored to drain a pericardial effusion secondary to central line leak. We found ectopic thymic tissue in 10 cases (33.3%). During a mean follow-up period of 53.5 months (range 9-180), complete remission was noted in 13 children (43.4%) and improvement in 14 (46.6%). The remaining three children (10%) did not improve following surgery. Univariate analysis (P < 0.05) showed that ectopic thymic tissue is a significant prognostic factor for outcome. CONCLUSION: Maximal thymectomy appears to provide a high rate of remission and improvement in children with MG. However, the presence of ectopic thymic tissue has poor prognostic value.     

Axial Compressive Strength Models of Eccentrically-Loaded Rectangular Reinforced Concrete Columns Confined with FRP

The majority of experimental and analytical studies on fiber-reinforced polymer (FRP) confined concrete has largely concentrated on plain (unreinforced) small-scale concrete columns, on which the efficiency of strengthening is much higher compared with large-scale columns. Although reinforced concrete (RC) columns subjected to combined axial compression and flexural loads (i.e., eccentric compression) are the most common structural elements used in practice, research on eccentrically-loaded FRP-confined rectangular RC columns has been much more limited. More specifically, the limited research has generally been concerned with small-scale RC columns, and hence, the proposed eccentric-loading stress-strain models were mainly based on the existing concentric-loading models of FRP-confined concrete columns of small scale. In the light of such demand to date, this paper is aimed at developing a mathematical model to better predict the strength of FRP-confined rectangular RC columns. The strain distribution of FRP around the circumference of the rectangular sections was investigated to propose equations for the actual rupture strain of FRP wrapped in the horizontal and vertical directions. The model was accomplished using 230 results of 155 tested specimens compiled from 19 studies available in the technical literature. The test database covers an unconfined concrete strength ranging between 9.9 and 73.1 MPa, and section’s dimension ranging from 100–300 mm and 125–435 mm for the short and long sides, respectively. Other test parameters, such as aspect ratio, corner radius, internal hoop steel reinforcement, FRP wrapping layout, and number of FRP wraps were all considered in the model. The performance of the model shows a very good correlation with the test results.