Joint International Conference on Long-term Experiments ...

MATERIALS AND METHODS
The material consisted of 53 male lung cancer patients operated for the cancer, and of 39
control patients who died of non-malignant diseases and were autopsied. Because
pulmonary emphysema is a good indicator for smoking, the control material was collected
to include cases with various degrees of emphysema. The smoking habits and occupational
history were required from the patients or next of kin and from the hospital records (Table
1). The severity of emphysema was graded in the radiographs of excised air-inflated lungs
or lobes of lungs.
Fresh lung tissue for analyses was taken from the (apico) posterior and anterior
segment of the upper lobe and from the superior (apical) segment and basal part of the lower
lobe. The samples, weighing 0.5-2 g, contained no pleural surface or cancer tissue. Ninety
percent of the Cd analyses were made from the anterior segment and 80% of the Cr analyses
from the (apico) posterior segment of the upper lobe. The samples were prepared under a
laminar flow hood avoiding contamination. The fresh, vacuum-dried samples were ashed in
glass cups with a blank and NBS Bovine Liver (SRM 1577) control for 48-72 h in a low
temperature oxygen plasma asher (BIO-RAD Plasma Asher E 2000, 100-120 °C). The
tissue residue was dissolved in a total of 3 ml of 50 % ethanol and transferred into a Teflon
cup and dried at 80 °C for 24 h. The residue was digested in a mixture of 3 ml of
concentrated nitric acid and 0.2 ml of percloric acid. The solution was allowed to stand
overnight and dry-heated at moderate temperature (100-150 °C) in a sand-bath. Finally the
ash was diluted in 3-6 ml of high quality water. The Cd and Cr contents were determined on
a direct current plasma atomic emission spectrometer (DCP-AES) (SpectraSpan IIIB
coupled with a Hewlett-Packard 85 data processor) not considering speciation. A standard
addition method was employed for Cr to eliminate matrix interference. The analytical
characteristics are shown in Table 2.
Table 2. Analytical characteristics
Cd Cr______
Accuracy
NBS 1577 Bovine Liver 0.36 0.25
(0.274 ±0.086) a (0.125±0.057) a
Lanonorm-Metalle 2 0.028
(0.021-0.030) b
RSD (0.02 ppm) % 3.9 2.4
Detection limit (ppm) 0.010 0.017
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RESULTS AND DISCUSSION
Both the total pulmonary Cd and Cr content were higher in the lung cancer (Cd 3.0 ± 2.4
and Cr 6.1 ± 4.2 µg/g dry weight) than in the control patients (Cd 2.1 ± 1.9 and Cr 4.1 ± 4.0
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