Strategy for finding new materials for ESR dosimeters

The right strategy for finding a new ESR dosimetric material sensitive to radiation is to follow the orthodox procedures used in the development of thermoluminescence dosimeters (TLD) and phosphorescence studies. Modern procedures used in materials sciences, such as computer calculation of molecular orbitals (MO), should be employed to estimate the ESR and optical properties of prospective materials. Radiation effects in lithium and magnesium sulfates and metal salts of organic acids, such as lithium and magnesium lactates, have been investigated in search for tissue-equivalent dosimeter with a large G value.

Thoracoscopic parasternal lymph node dissection for the staging of breast cancer.

With the advent of advanced thoracoscopic techniques, new applications have been expanding their roles in thoracic surgery. The aim of this paper is to introduce our new thoracoscopic approach in performing parasternal lymph node dissection of advanced breast cancer for its staging. This technique does not need the removal of any costal cartilage which is usually done in the conventional classical technique after radical mastectomy. Thoracoscopic procedure, in which wide and complete parasternal lymph node dissection is done, is minimally invasive and easy to perform. Therefore, the thoracoscopic technique may be a suitable alternative to the conventional approach in the future.

Thoracoscopic surgery combined with a supraclavicular approach for removing superior mediastinal tumor.

This report introduces our new technique of thoracoscopic surgery combined with a supraclavicular approach for removing superior mediastinal tumor. A 68-year-old woman noticed a tumor palpable in the left supraclavicular fossa. The patient had no pain around the neck and shoulder. A radio-opaque shadow 6 cm in diameter was detected in her left apical lung field on chest roentgenogram. Chest CT and MRI showed that the tumor was located in the superior mediastinum, extending up to the thoracic inlet, and there was no invasion of the surroundings. At first, a thoracoscopic examination was performed to assess the possibility of the excision. After dissecting the tumor from the mediastinal tissue and the first costovertebrae as far as possible by thoracoscopic surgery, a supraclavicular approach was used to enter the thoracic cavity. Complete resection of the tumor was successfully performed by thoracoscopic surgery combined with a supraclavicular approach. The tumor was removed in a plastic bag through the supraclavicular defect. Postoperative histopathology revealed that the tumor was a benign neurogenic one. A satisfactory follow-up of 5 postoperative days was observed without any complications, and the patient was discharged. The procedure was safe, easy, and minimally invasive to perform. Moreover, the supraclavicular approach could be used to add trocar port if needed.

Thoracoscopic treatment of esophagobronchial fistula with esophageal diverticulum.

Thoracoscopic fistulectomy and diverticulectomy for esophagobronchial fistula with esophageal diverticulum were performed on a 49-year-old-woman. The neck of the diverticulum and the fistula were divided with endo-stapling technique. Intraoperative esophagoscopy was found to be useful for the definite localization and complete excision of the fistula and the diverticulum and the avoidance of stenosis of the esophagus. To avoid the recurrence of fistula, a pedicle of viable mediastinal pleura was interposed between esophageal and bronchial closures. Postoperative course was uneventful, and the complete relief of symptom was experienced for a period of 10 months after the operation. It is to be considered that the present thoracoscopic procedure with intraoperative esophagoscopy can be used as a standard operative procedure for esophagobronchial fistula with esophageal diverticulum.

Secondary structural changes of metmyoglobin and apomyoglobin in anionic and cationic surfactant solutions: effect of the hydrophobic chain length of the surfactants on the structural changes.

Secondary structural changes of metmyoglobin and apomyoglobin were examined in solutions of sodium alkylsulfates with hydrocarbon numbers of 8 and 12, and alkyltrimethylammonium bromides with hydrocarbon numbers of 10, 12, 14, and 16. The relative proportion of alpha-helical structure was estimated by the curve-fitting method of circular dichroic spectrum. The helical proportions of metmyoglobin and apomyoglobin were 82 and 63%, respectively. The shorter the hydrocarbon chain the surfactant had, the higher the concentration necessary to disrupt the secondary structures of these proteins. However, the helical proportion had a tendency to decrease down to lower values in solutions of the cationic surfactants with short hydrophobic groups. On the other hand, the alpha-helical structure of apomyoglobin was disrupted in lower concentrations of each cationic surfactant than that of metmyoglobin, although the disruptions of the same structures in both the proteins occurred in the same concentration range of each anionic surfactant. It appeared likely that the removal of the heme group unstabilized the myoglobin conformation only in the cationic surfactant solutions.