title: [Oxygen pressure distribution in lymph node metastases and the changes during acute respiratory hypoxia].
abstract: OBJECTIVE
  The radiosensitivity of tissues is essentially influenced by hypoxia. Based on the oxygen effect a new therapeutic modality has been developed to protect healthy tissues while hypoxic breathing during irradiation.
  
  
  METHODS
  The effect of hypoxic breathing (8.1% O2) on the pO2 in metastatic lymph nodes was studied in 14 patients. Tissue oxygenation was assessed using a polarographic electrode system.
  
  
  RESULTS
  The median pO2 was 19.6 mm Hg prior to hypoxic breathing with a great intra- and intertumoral variability. The relative frequency of pO2-values < 5 mm Hg was between 0 and 88%. During hypoxic breathing we registered no significant changes in the mean, the median or the pO2 values < 5 mm Hg.
  
  
  CONCLUSIONS
  In metastatic lymph nodes can be found chronic hypoxia with great inter- and intratumoral pO2 variability. The hypoxic breathing (8.1% O2) shows no significant modifications of the tumor oxygenation with increased pO2 variability. This fact explains the experimental and clinical experience, that the hypoxic breathing (8 to 10% O2) protects the healthy tissue without changes in the radiosensitivity of chronic hypoxic tumor tissue.
authors.affiliation: Klinik und Poliklinik für Strahlentherapie, Universität Erlangen-Nürnberg.
authors.forename: V
authors.initials: V
authors.lastname: Strnad
authors.forename: L
authors.initials: L
authors.lastname: Keilholz
authors.forename: M
authors.initials: M
authors.lastname: Kirschner
authors.forename: M
authors.initials: M
authors.lastname: Meyer
authors.forename: R
authors.initials: R
authors.lastname: Sauer
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D008198:Lymph Nodes / Q000378:metabolism*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009333:Neck; D009369:Neoplasms / Q000378:metabolism*; D010101:Oxygen Consumption; D010313:Partial Pressure; D011836:Radiation Tolerance