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  • Aromaticity  (1)
  • Key words: early gastric cancer  (1)
  • 1995-1999  (2)
  • 1980-1984
  • 1955-1959
  • 1999  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 1434-1948
    Keywords: Phosphorus heterocycles ; Aromaticity ; Phosphenium cations ; Ab initio calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aromatic stabilization of cyclic phosphenium cations (general type C2N2P+) was studied by experimental methods (synthesis, multinuclear NMR, single crystal X-ray crystallography) and quantum chemical calculations (ab initio methods). The structures of the 1,3,2-diazaphosphole derivatives [(tBuN-CH=CH-NtBu)P+]Cl- (1), (tBuN-CH2-CH2-NtBu)P-Cl (2), [(tBuN-CH=CH-NtBu)P]+PF6- (3) and [(tBuN-CH2-CH2-NtBu)]P+PF6- (4) were examined by single crystal X-ray diffraction. The chloro phosphane [(tBuN-CH=CH-NtBu)P]+Cl- (1) has an ionic P-Cl bond and contains an aromatically stabilized phosphenium cation [shortest distance P···Cl = 275.9(2) pm], while the CC-saturated compound (tBuN-CH2-CH2-NtBu)P-Cl (2) is covalent. The two chloro-phosphanes 1 and 2 differ sharply in their volatility and solubility in organic solvents. Compound 2 is soluble in hydrocarbons and sublimes readily at 90 °C/0.1 Torr but 1 is insoluble in hexanes and not volatile below 180 °C/0.1 Torr. The degree of aromatic stabilization in the phosphenium cation 1 was investigated by ab initio methods. For the model cations [RN-CH2-CH2-NR]P+ and [(RN-CH=CH-NR)P]+, thermochemical stabilization energies of 25.8 kcal · mol-1 (R = H) and 28.1 kcal · mol-1 (R = Me) were obtained from isodesmic hydrogenation reactions at the RHF/MP2/6-31G*//RHF/6-31G* level.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1436-3305
    Keywords: Key words: early gastric cancer ; Japanese-type radical resection ; long-term results
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Background. Long-term survival following Japanese-type radical surgery for 130 consecutively performed early gastric cancers (EGC) in a single Austrian institution between January 1, 1984 and May 31, 1998 was analyzed in terms of long-term survival, postoperative morbidity, and mortality. Methods. Extended D2 lymphadenectomy as defined by the JRSGC was performed in 129 patients with EGC. The surgical process was consistent as nearly all patients were operated on by only two surgeons. Overall survival and factors influencing survival were analyzed with particular regard to the depth of tumor infiltration, histological type, tumor grading, Lauren classification, tumor diameter, macroscopic appearance, localization, and lymph node involvement. Results. Of 678 gastric cancer patients surgically treated in the mentioned period, 130 patients (19.2%) were qualified as EGC. In 70 patients the tumor was limited to the mucosa and in 60 patients the tumor had not yet invaded the submucosa. The percentage of patients with positive lymph nodes increased from 2.9% with mucosal invasion to 21.7% with submucosal tumor involvement. The overall 5- and 10-year observed survival rate, postoperative mortality not excluded, was 74.6% and 62.1%, respectively, and 91.1% and 91.1%, respectively, when calculated as tumor specific. The 5- and 10-year observed survival rate of tumors limited to the mucosa was 77.2% and 72.1%, respectively, and 98.1% and 98.1%, respectively, when calculated as tumor specific. The respective values for submucosal invasion were 71.6% and 51.7%, and 82.7% and 82.7%. Postoperative complications occurred in 17 patients (13.1%) and postoperative hospital mortality totaled 1.5% (2/130). In multivariate analysis, only lymph node metastases were found to have independent prognostic influence on survival (P 〈 0.001; hazard ratio, 8.25). Conclusion. Japanese-type radical lymph node dissection for EGC in a European surgical institution yielded long-term survival nearly identical to that reported repeatedly by Japanese authors. Postoperative morbidity and mortality was not sacrificed by our comparatively radical surgical approach.
    Type of Medium: Electronic Resource
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