Gauche, ortho, transoid and anti conformations of the tetrasilanes SiMe3SiX2SiX2SiMe3 (X=H, F, Cl, Br, I): a computational and vibrational spectroscopic study.

The energy profile for rotation around the central Si-Si bonds of the tetrasilanes SiMe3SiX2SiX2SiMe3 (X=H, F, Cl, Br and I) were examined by ab initio calculations and temperature-dependent Raman spectroscopy. Ethanelike intrinsic barriers to rotation were found for X=H, Cl, Br and I. MP2 calculations predict for SiMe3SiF2SiF2SiMe3 the existence of a gauche minimum with backbone dihedral angle ω≈64° and a twisted minimum with ω≈115°, as shown in the picture (solid line=HF, dashed line=MP2). The curious 115° local minium can be accounted for by a unique intrinsic barrier to rotation superimposed by electrostatic interactions involving strongly polar SiF bonds.

Catamenial pneumothorax--3 case reports and view of literature.

INTRODUCTION: The unusual correlation between chronic recurring spontaneous pneumothorax and the menstrual cycle, was first presented by Maurer in 1958. In our clinic we had 3 cases in 5 years. The anamnesis shows that this syndrome is unknown to many of our colleagues. Not mentioned in several standard textbooks, warrants our attention. METHODS: In 5 years we had 3 cases of C.P., all of them had already on admission, at least one recurrence; all of them had right sided thoracic pain and dyspnoea. They undergone video-assisted thoracoscopy, with histological examination of diaphragm specimen. Gynaecological consultations was followed by hormonal therapy and follow up. RESULTS: In all 3 cases we found no signs of lung defects or bullae, instead, we identified diaphragm defects of different extension, even a liver prolapse in one of the cases. Endometriosis extra genitalis could be diagnosed in only one case which undergone a hysterectomy 8 years before. CONCLUSION: A spontaneous pneumothorax which recurs in correlation with menses has a pathogenesis which concern only women, that is why is referred to as catamenial. Our experience supports the hypothesis, that air in the pleural cavity originates from the peritoneal one, arriving here via uterus and tuba. Beside the symptomatic therapy ther is an etiological one, by inhibition the menstrual cycle. Thoracosurgical intervention could help preventing recurrence, and contributes in clarifying the pathogenesis.

Postoperative complications after bronchoplastic procedures in the treatment of bronchial malignancies.

OBJECTIVE: The purpose of this study was to determine the frequency of postoperative complications after bronchoplastic procedures in the treatment of pulmonary malignant tumors and to analyze the factors influencing the complication rate. METHODS: During a 5-year-period (1992-1996) 79 patients (68 male, 11 female, mean age 57 years) underwent reconstructive operations for bronchial malignancies. We performed 58 bronchoplastic procedures and 21 combined broncho- and angioplastic procedures. Among the bronchoplastic procedures the number of sleeve resections (n = 44) and wedge resections (n = 35) were comparable. RESULTS: Fifty-nine patients (74,7%) showed a regular postoperative course; 12 patients (15,2%) had severe postoperative complications (death, re-operation). Concerning the primary operation the operative 30-day mortality was 5.1% (n = 4) and including the two deaths after re-operation it was 7.6% (n = 6). After subdividing the patients into three groups (severe, less severe and no complications) we tried to determine predictors for occurrence of postoperative complications. There was a higher rate of severe complications in the age group 61-70 years (6/25 = 24%) as compared with younger patients between 51 and 60 years (4/38 = 10,5%; P < 0,05). Concerning the location, the outcome was better after sleeve- or wedge lobectomies of the upper lobes (four complications/51 patients = 7.8%) compared with procedures of the lower lobes (3/14 = 21.4%). The data could not prove a lower frequency of severe postoperative complications or specific morbidity after pleural coverage following bronchial sleeve resection. The complication rate was higher when sleeve resection of the bronchus was performed (10/44 = 22.7%) as compared with wedge resections (2/35 = 5.7%; P = 0,011) and after resection of T3/T4 tumors (6/28 = 21,4%) compared with T1/T2 tumors (4/37 = 10.8%; P < 0,05). CONCLUSIONS: Bronchoplastic procedures represent a fairly safe therapy opportunity in patients with centrally localized bronchial carcinoma and compromised or uncompromised pulmonary function. In this study the complication rate was higher after sleeve resection of the bronchus as compared with wedge resection. Pleural coverage of the anastomosis was not effective to prevent major complications due to dehiscence of the bronchial anastomosis. A pedicled muscle flap could be a valuable alternative.

[Thoracic surgery relevant indications for adjuvant and/or palliative measures in breast carcinoma]. / Thoraxchirurgisch relevante Indikationen zu adjuvanten und/oder palliativen Massnahmen beim Mammakarzinom.

Metastatic lesions of breast cancer represent rare indications for operation in thoracic surgery. Only in case of persistent malignant pleural effusions or in case of tumour progress despite all other available therapy modalities thoracic surgery can be indicated. Over a period of 5 years between 1993 and 1997 53 patients with metastatic breast cancer were treated in our institution. 36 pts. suffered from persistent pleural effusions, 13 pts. had pulmonary metastases and 4 pts. had metastases involving the chest wall. In all these patients the disease could not be controlled by conservative measures. Our experiences are the following: Thoracoscopy is the diagnostic method of choice for pleural effusions in patients with malignant tumors. If a malignant pleural effusion is confirmed, a talc poudrage represents the most reliable treatment to palliate the dyspnea. The resection of a single solitary pulmonary metastasis can be indicated to confirm the histologic type of the nodule. Resections for centrally localized lesions causing hemoptysis or atelectasis represent rare occasions. Metastatic lesions of breast cancer involving the ribs or the sternum are resected in order to confirm the histologic diagnosis. According to the literature these procedures, with a 5-year survival rate of 50% and without perioperative mortality, can be beneficial.