ABSTRACT
Turbot (Scophthalmus maximus) were exposed to two sublethal concentrations (1 and 10 mg metal/l) of cadmium (8.9 and 89 microM Cd), copper (15.26 and 152.6 microM Cu) and zinc (15.3 and 153 microM Zn) for 7 days, and afterwards were maintained depurating for 14 days. Immunoreactive metallothioneins (irMTs) and metal ions were localized in the branchial epithelium by immunohistochemistry (using an anti-Cod MT antibody) and autometallography (AMG), respectively. Metal ions were demonstrated by AMG as black silver deposits (BSD), mainly in mucocytes (MC) and to a lesser extent in the other branchial cell-types (respiratory cells (RC), chloride cells (CC) and basal layer cells (BLC)). Irrespective of the metal supplied, BSD were rapidly visualized in MC after 1 h of exposure. This accumulation did not increase with increasing exposure time and concentration. Metallothionein expression was mainly observed in mature CC in the interlamellar space for all exposure conditions and it was shown that all mature cells express the same amount of irMT. The number of CC exhibiting irMT in metal-exposed turbots increased following short exposure times (1 h-1 day) in the filament epithelium and following longer exposure times (1-7 days) in the secondary lamellae. Total levels of irMT in the gills (quantified by image analysis and densitometry) increased significantly in metal-exposed turbot and were related to increased exposure times. It can be concluded that the total content of irMT in the gills of metal-exposed turbot is governed by changes in the number of mature CC expressing the protein. The quantification of total irMT in branchial CC can be considered as a reliable biomarker of metal exposure since reflects changes in metal bioavailability. This approach based on cell-selective immunohistochemistry can be simplified by only quantifying the number of mature CC. In addition, the dramatic increase of CC in the gills that produces epithelial thickening of the FE enhances migration of CC up to the edge of the SL and provokes the hypertrophy and fusion of secondary lamellae can be considered as unspecific biomarkers of effect indicating disturbed health in turbot.
Subject(s)
Flatfishes/physiology , Gills/drug effects , Metallothionein/biosynthesis , Metals/toxicity , Analysis of Variance , Animals , Biomarkers/analysis , Cell Count/veterinary , Densitometry/veterinary , Epithelium/drug effects , Gills/metabolism , Gills/pathology , Histocytochemistry/veterinary , Immunohistochemistry/veterinary , Metallothionein/analysis , Metallothionein/drug effects , Metals/analysis , Polarography/veterinary , Time FactorsABSTRACT
BACKGROUND AND PURPOSE: Tumor oxygenation predicts treatment outcome, and reoxygenation is considered important in the efficacy of fractionated radiation therapy. Therefore, the purpose of this study was to document the changes of the oxygenation status in spontaneous canine tumors during fractionated radiation therapy using polarographic needle electrodes. MATERIAL AND METHODS: Tumor oxygen partial pressure (pO(2)) measurements were performed with the Eppendorf-pO(2)-Histograph. The measurements were done under general anesthesia, and probe tracks were guided with ultrasound. pO(2) was measured before radiation therapy in all dogs. In patients treated with curative intent, measurements were done sequentially up to eight times (total dose: 45-59.5 Gy). Oxygenation status of the palliative patient group was examined before each fraction of radiation therapy up to five times (total dose: 24-30 Gy). RESULTS: 15/26 tumors had a pretreatment median pO(2) < or = 10 mmHg. The pO(2) values appeared to be quite variable in individual tumors during fractionated radiation therapy. The pO(2) of initially hypoxic tumors (pretreatment median pO(2) < or = 10 mmHg) remained unchanged during fractionated radiotherapy, whereas in initially normoxic tumors the pO(2) decreased. CONCLUSION: Hypoxia is common in spontaneous canine tumors, as 57.7% of the recorded values were < or = 10 mmHg. The data of this study showed that initially hypoxic tumors remained hypoxic, whereas normoxic tumors became more hypoxic.
Subject(s)
Dog Diseases/metabolism , Dog Diseases/radiotherapy , Neoplasms/veterinary , Oxygen/metabolism , Animals , Cell Hypoxia/radiation effects , Dogs , Dose Fractionation, Radiation , Dose-Response Relationship, Radiation , Female , Male , Neoplasms/metabolism , Neoplasms/radiotherapy , Polarography/veterinary , Radiotherapy Dosage , Treatment OutcomeABSTRACT
BACKGROUND: Poor tumour oxygenation is associated with radiation resistance. The recording of pre-treatment oxygenation status has been shown to be of prognostic relevance. MATERIAL AND METHODS: Eleven dogs with spontaneously arising soft tissue sarcomas were included in this study. Oxygen partial pressure measurements (pO2) were performed with the Eppendorf method. RESULTS: The mean of median pO2 was 9.6 mmHg (range: 0.1-30 mmHg). Four of the nine dogs included in the statistical analysis showed a median pO2 < or = 2.5 mmHg. The natural logarithm of the hypoxic subvolume correlated with the hypoxic fraction < or = 2.5 mmHg (p = 0.0712) and < or 5 mmHg (p = 0.0988). Mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) correlated significantly to several oxygen parameters. CONCLUSION: Hypoxia exists in spontaneous canine soft tissue sarcomas and the dog can be used as a reliable model for repeated oxygenation measurements. Ultrasonography assures reliability of needle placement.
