[Foreign substances in maternal milk]. / Cizorodé látky v materském mléce.

In 1984-1985 72 specimens of human milk were examined for hexachlorobenzene, DDE and polychlorinated biphenyls and 69 specimens for lead and cadmium. The residual levels (expressed in mg.kg-1 milk fat) were as follows: hexachlorobenzene 1.97 (0.24-5.58), DDE 1.56 (0.17-5.80) and polychlorinated biphenyls 3.18 (1.28-9.08). All specimens were positive. The lead levels were 1.68 (less than 0.10-6.75), cadmium levels 0.31 (less than 0.05-1.08) ng.ml-1 milk. Lead was present in 94.2%, cadmium in 98.6% specimens. The results were compared with other areas of the CSSR, data from the literature and hygienic standards. The authors discuss limited or discontinued breastfeeding in high occupational exposure. Finally they emphasize advantages associated with breastfeeding and the justification of a prolactation programme.

Use of N-methyl-D-glucamine as buffer in the determination of serum alkaline phosphatase activity.

We describe a method for determining serum alkaline phosphatase activity with use of N-methyl-D-glucamine buffer, Na+ is a definite activator, whereas NH4+ and Li+ inhibit enzyme activity. Optimum reaction conditions are: methylglucamine buffer, 0.35 mol/L, pH 10.2 +/- 0.1 (30 degrees C); NaCl, 70 mmol/L; MgCl2, 0.5 mmol/L; disodium 4-nitrophenyl phosphate, 15 mmol/L; reaction temperature, 30 degrees C; reaction time, 2 min. The assay conditions are optimum for all human serum isoenzymes.