Search

From May to August 1987, 137Cs activity was measured in a total-body counter (4 pi counter) in 33 premature and mature newborns (group I), 40 infants and young children up to 2 4/12 years of age (group II), and 15 children between 3 and 6 8/12 years (group III), all from Bonn or its environs. The mean of measurements in group II, at 3.7 Bq/kg body-weight, was lower than that of group I (5.8 Bq) and III (9.4 Bq). Mean radiation exposure, calculated from these data, was 1.7 mrem/a for group I, 1.1 mrem/a for group II, and 2.8 mrem/a for group III. A comparison with present Cs values in adults and measurements made at the end of the 1950's and beginning of 60's showed good agreement. There were no significant differences, as regards Cs activity, between newborns or infants who had been formula-fed or breast-fed. The measured radiation exposure of the three groups is about 1% of natural radiation exposure. Thus, present-day results indicate that there will be no damage to health outside the natural scatter.

Cesium 137 activity was measured after the Chernobyl incident in a whole-body radiation counter (4-π-scintillation counter) in 85 premature and mature newborns (group 1), 174 infants and young children up to 2 11/12 years (group 2), and 48 children between 3 and 8 years (group 3) from Bonn (Germany) and surroundings. In 1987 the mean level of radioactivity in group 2, at 3.7 Bq/kg body weight corresponding to a mean radiation exposure of 11 µSv/y, was lower than that of group 1 (5.8 Bq/kg, 17 µSv/y) and 3 (9.4 Bq/kg, 28 µSv/y). Up to 1990 the values of all groups revealed a continuous decrease. The latest measurements showed mean values of 0.5 Bq/kg (1.5 µSy/y) in group 1, 0.6 Bq/kg (1.8 µSv/y) in group 2, and 0.8 Bq/kg (2.4 µSv/y) in group 3. A comparison with present cesium 137 values and determinations at the end of the 1950s and beginning of 1960s, both in adults, showed good agreement. The effective dose-equivalent rates amounted to less than 1% of that from natural radiation exposure. These levels should present no teratogenic risks to the population studied and, while there are theoretical mutagenic risks, the dose is so low that no increase in measurable mutagenic effects should be observed.

Proteinase levels were assessed in organ culture fluids from human neonatal foreskin maintained under growth factor-free conditions and in the presence of a combination of growth factors (ie, epidermal growth factor, insulin, hydrocortisone, pituitary extract, and all-trans-retinoic acid). Analysis of culture fluids by gelatin zymography revealed the presence of 92-kd and 72-kd gelatinases. There was a greater amount of 92-kd gelatinase activity in the presence of growth factors whereas the levels of 72-kd gelatinase were similar in growth factor-free and growth factor-containing media. Experiments with keratinocytes and fibroblasts in monolayer culture and with isolated dermal tissue in organ culture indicated that the epithelial component was responsible for most of the 92-kd gelatinase activity whereas fibroblasts were primarily responsible for the 72-kd gelatinase activity. Activation with aminophenyl mercuric acetate, requirement for divalent cations, inhibition with EDTA, and insensitivity to inhibition with phenylmethyl sulfonyl fluoride indicated that both gelatinases were metalloproteinases. In additional studies, culture fluids were examined for the presence of plasminogen activator activity. This was detected in culture fluids from tissues maintained under both conditions but was increased in the growth factor-containing medium. The increased amount seen in the growth factor-containing medium appeared to be due almost entirely to a single factor, ie, all-trans-retinoic acid. In monolayer culture, both keratinocytes and fibroblasts produced plasminogen activator; the level was higher in keratinocyte culture fluids than in culture fluids from fibroblasts.