The sugar absorption test is the usual test for measurement of intestinal permeability. After intestinal absorption of probe sugars the subsequently excreted sugars are measured in urine. We have developed four enzymatic methods for the measurement of the urinary concentration of the probe sugars mannitol, raffinose, lactose and sucrose. Mannitol, lactose and sucrose are directly measured on Hitachi 917 using mannitol dehydrogenase, beta-galactosidase and invertase, respectively, as enzyme reagents. Raffinose measurement needs a three hours preincubation with alpha-galactosidase, after which the liberated sucrose is measured. The analytical performances such as within- and between-run precision, linearity, lowest detection limit, interference of other sugars and comparison with a gas chromatographic method are described for the four methods. These methods are accurate an can easily be performed in any clinical laboratory.

SUMMARY.Aluminium in human tissues has been determined by flameless atomic absorption spectroscopy (AAS). Tissues were dried at l lff'C and digested with concentrated nitric acid at SO°C overnight. After dilution with distilled water the samples were measured. The aluminium levels of the controls (healthy individuals who died as a result of an accident) appeared to be: grey matter 2·1 ± 1·0 (mean±SD), white matter 1·7±0·S, spinal cord 3·3±1·S, kidney 1·9±0·7, heart 2·1±1·1, vertebral cortex 1·9±1·8, and vertebral trabeculae 3·1±1·8 Ilg/g dry weight. For a patient with dialysis motor neuropathy significantly higher values were found. Comparison with values in the literature shows that our reference values are in agreement with published results obtained by flameless atomic absorption spectroscopy.

SUMMARY.Urinary cobalt was determined by flameless atomic absorption spectroscopy. Three methods were compared: (i) direct analysis with deuterium background correction after l l-fold dilution with distilled water (method D), (ii) analysis with deuterium background correction after extraction of cobalt from the urinary matrix in organic solution (method E), and (iii) direct analysis with Zeeman background correction (method Z). The detection limit of the direct analysis of urinary cobalt with deuterium background correction was 6 Ilg/L, this appeared to be insufficient for the determination of reference values and moderate enlarged cobalt values. Comparison of the extraction method and the Zeeman method revealed that these methods have similar reference values, detection limits, precision and recovery.Cobalt is an essential trace element that is required in the normal diet of man as a component of vitamin B12. In larger doses cobalt is toxic and is associated with a wide spectrum of clinical syndromes such as pneumoconiosis, allergy, cardiomyopathyI and, in animals, cancer. I It is therefore of interest to monitor this metal in the biological fluids of exposed workers. Cobalt is rapidly excreted and concentrations in urine and serum show a close correlation. 2