Biofilm removal effect of diatom complex on 3D printed denture base resin.

For patients who have difficulty in mechanical cleaning of dental appliances, a denture cleaner that can remove biofilm with dense extracellular polymeric substances is needed. The purpose of this study is to evaluate the efficacy of diatom complex with active micro-locomotion for removing biofilms from 3D printed dentures. The diatom complex, which is made by doping MnO2 nanosheets on diatom biosilica, is mixed with H2O2 to generate fine air bubbles continuously. Denture base resin specimens were 3D printed in a roof shape, and Pseudomonas aeruginosa (107 CFU/mL) was cultured on those for biofilm formation. Cleaning solutions of phosphate-buffered saline (negative control, NC), 3% H2O2 with peracetic acid (positive control, PC), denture cleanser tablet (DCT), 3% H2O2 with 2 mg/mL diatom complex M (Melosira, DM), 3% H2O2 with 2 mg/mL diatom complex A (Aulacoseira, DA), and DCT with 2 mg/mL DM were prepared and applied. To assess the efficacy of biofilm removal quantitatively, absorbance after cleaning was measured. To evaluate the stability of long-term use, surface roughness, ΔE, surface micro-hardness, and flexural strength of the 3D printed dentures were measured before and after cleaning. Cytotoxicity was evaluated using Cell Counting Kit-8. All statistical analyses were conducted using SPSS for Windows with one-way ANOVA, followed by Scheffe's test as a post hoc (p < 0.05). The group treated with 3% H2O2 with DA demonstrated the lowest absorbance value, followed by the groups treated with 3% H2O2 with DM, PC, DCT, DCT + DM, and finally NC. As a result of Scheffe's test to evaluate the significance of difference between the mean values of each group, statistically significant differences were shown in all groups based on the NC group. The DA and DM groups showed the largest mean difference though there was no significant difference between the two groups. Regarding the evaluation of physical and mechanical properties of the denture base resin, no statistically significant differences were observed before and after cleaning. In the cytotoxicity test, the relative cell count was over 70%, reflecting an absence of cytotoxicity. The diatom complex utilizing active micro-locomotion has effective biofilm removal ability and has a minimal effect in physical and mechanical properties of the substrate with no cytotoxicity.

A totally thoracoscopic ablation for persistent atrial fibrillation.

We report the case of a 72-year-old female with persistent atrial fibrillation who underwent a totally thoracoscopic ablation. A successful normal sinus conversion was achieved.

Complete stable remission after extended transsternal thymectomy in myasthenia gravis.

OBJECTIVE: This study sought to determine the efficacy and prognostic factors of extended transsternal thymectomy as a treatment for myasthenia gravis (MG). METHODS: Medical records of 147 patients who underwent extended transsternal thymectomy for MG from January 1991 to December 2002 were reviewed retrospectively. The complete stable remission (CSR) rate and prognostic factors for CSR were assessed in 106 female and 41 male patients. RESULTS: The median age was 35 years (range 11-75 years). Ninety-eight patients had non-thymomatous MG and 49 patients had thymomatous MG. The median follow-up time was 89.7 months (range 12-167 months). Both non-thymomatous MG and thymomatous MG exhibited significant differences in population characteristics and CSR rates (29.6% vs 13.3% at 5 years, 45.2% vs 27.7% at 10 years, p = 0.022). Steroid therapy (hazard ratio: 0.234, p = 0.003) was a poor prognostic factor, while early onset (hazard ratio: 3.519, p = 0.048) was a good prognostic factor for CSR in non-thymomatous MG. In contrast, steroid therapy (hazard ratio: 0.061, p = 0.034) was poor prognostic factor for thymomatous MG. CONCLUSIONS: Extended transsternal thymectomy is a good treatment tool to achieve CSR in MG. Thymomatous MG and non-thymomatous MG were significantly different in patient characteristics and prognosis. Prognostic factors were steroid therapy and age of onset in non-thymomatous MG, and steroid therapy in thymomatous MG.

Prognostic and clinical relevance of the World Health Organization schema for the classification of thymic epithelial tumors: a clinicopathologic study of 108 patients and literature review.

STUDY OBJECTIVES: Controversy has ensued about the prognostic relevance of the new World Health Organization (WHO) schema for the classification of thymoma. In this study, we present the clinical and histologic features of 108 thymomas and evaluate the usefulness of this histologic schema in view of the prognosis. DESIGN: Retrospective, clinicopathologic analysis of our experience and a review of recent literature. SETTING: Department of Thoracic and Cardiovascular Surgery of a university hospital. METHODS: A series of 108 thymomas were reviewed and classified by the new WHO schema. The clinical characteristics and the survival outcome were investigated in reference to the WHO subtypes. The Cox proportional hazards model was applied to determine the factors affecting the tumor-related survival. Recent literature on the prognostic relevance of the WHO schema was reviewed. RESULTS: There were 7 type A tumors, 25 type AB tumors, 12 type B1 tumors, 32 type B2 tumors, 20 type B3 tumors, and 12 type C tumors. The histologic subtype closely correlated with the Masaoka stage (p = 0.00). The tumor-related survivals at 5 years and 10 years were 88.0% and 77.9%, respectively. Stage III and IV tumors had a significantly worse prognosis than stage I or II tumors (p < 0.05). Type B3 tumors had an intermediate prognostic ranking in comparison with the carcinomas and with the other groups. On multivariate analysis, the WHO subtype (A-B2 vs B3 vs C) could predict the tumor-related survival, but the Masaoka stage was the most important prognostic factor affecting the postoperative survival (p = 0.026). CONCLUSION: The Masaoka stage is the most important determinant of survival in surgically resected cases of thymoma. To clarify the prognostic relevance and clinical usefulness of the WHO schema, consistent parameters reflecting the surgical outcome and development of the diagnostic tools that could improve the interobserver agreement within type B are needed.

Change in pulmonary function following empyemectomy and decortication in tuberculous and non-tuberculous chronic empyema thoracis.

Chronic empyema thoracis results from various etiologies. Improvement in pulmonary function after empyemectomy and decortication has proved difficult to predict when the etiology of chronic empyema thoracis is tuberculosis. The purpose of this study was to confirm the changes in pulmonary function according to the etiology after an operation. Sixty-five patients were classified into two groups according to their etiology: Group A (tuberculous) and Group B (non-tuberculous), and they were retrospectively evaluated with regard to their forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), percentage of predicted normal value of FEV1 (% FEV1) and FVC (%FVC). Empyemectomy and decortication was performed for all the patients and the two groups were similar in age, gender and preoperative spirometric parameters. In Group A (n=41), the pre- and postoperative mean values were 2.31 L and 2.8 L in FEV1, 65.8% and 80.5% in %FEV1, 2.62 L and 2.55 L in VC, 61.9% and 71.8% in %VC, respectively. In Group B (n=24), the pre- and postoperative mean values were 2.13 L and 2.49 L in FEV1, 66.4% and 73.8% in %FEV1, 2.55 L and 2.95 L in FVC, 64.9% and 71.8% in %FVC, respectively. All the spirometric parameters improved significantly in both groups compared to their preoperative values. However, no significance was shown in the rate of increase of the spirometric parameters between the two groups. In conclusion, improvement of lung function is expected after empyemectomy and decortication, regardless of the etiology of the chronic empyema thoracis.