Response of a Shadow-Shield Whole-Body Counter to a Variety of Physical Phantoms.

The performance characteristics of a shadow-shield whole-body counter system with an array of four high-resolution germanium detectors using whole-body and organ-specific (lungs, liver, head, knee and thyroid) physical phantoms are described. Detection efficiency and minimum detectable activities for selected radionuclides and several measurement configurations are presented. Results demonstrate that the system meets the requirements for direct radio bioassay and that detection efficiency and minimum detectable activities are similar in magnitude to other whole-body (or organ) counting systems installed in fully shielded structures.

Decreased insulin-like growth factor-I receptor sites on circulating mononuclear cells from children with acute leukemia.

Insulin-like growth factor-I (IGF-I) is a known mitogen for various cell types, including those of the hematopoietic cell system. To study the role of IGF-I in the neoplastic process of leukemia in children, the authors have determined the number of IGF-I binding sites on circulating mononuclear cells of children with acute leukemia as compared to normal children, using binding assays. The IGF-I binding sites per cell on peripheral mononuclear cells of children with leukemia decreased compared to those of the control group (411 +/- 73 and 1334 +/- 227, respectively, p < .001), while their affinity increased (Kd = 0.14 +/- 0.04 and 0.43 +/- 0.16, respectively, p = .05). Furthermore, in the patients, the number of the IGF-I binding sites was significantly lower in the subgroup of the peripheral mononuclear cells, which included lymphocytes and monocytes, as compared to their number in the peripheral blast cells (254 +/- 43.6 and 536 +/- 98.6, respectively, p = .02). A significant reduction was found in serum GHBP levels in the patients as compared to the controls (28.21 +/- 1.93 and 35.83 +/- 2.90, respectively, p = .02), while serum IGF-I and growth hormone levels were similar in patient and control groups. These results suggest a possible involvement of IGF-I in childhood acute leukemia, but further studies are needed to establish whether IGF-I plays a role in this disease.

Changes in body composition of patients with subnormal spontaneous secretion of growth hormone, during the first year of treatment with growth hormone.

The effects of 1 year of growth hormone (GH) therapy were studied in 10 subjects with subnormal spontaneous secretion of GH, whose ages ranged from 6.5 to 12.4 years. Height, weight, body fat percentage, total body potassium (TBK), and extracellular water (ECW) were measured prior to initiating the treatment, and thereafter at 6 months (period 1) and 12 months (period 2). Height velocity almost doubled during the year of treatment: 7.8 +/- 0.8 and 7.1 +/- 0.7 cm/yr (P less than .0001) during periods 1 and 2, respectively, as compared with 3.9 +/- 0.6 cm/yr pretreatment. Body fat percentage decreased during period 1 to 18.2% +/- 4.9%, versus 16.3% +/- 4.5% (P less than .02), but stabilized thereafter (16.3% +/- 4.9%). Mid-arm muscle circumference (MAMC) and TBK increased in accordance with the predicted values for age. Body mineral density (BMD) increased both in absolute and standardized terms. No changes were found in ECW during treatment. We concluded that GH treatment in children with subnormal spontaneous secretion of GH has mainly a lipolytic effect on body composition, and that resistance to the lipolytic effect develops during the course of therapy.

Concentrations of U and Po in animal feed supplements, in poultry meat and in eggs.

The present study was undertaken to assess the contribution of phosphate feed supplements to the radiation exposure of the population in Israel. The phosphates usually contain appreciable quantities of U and its daughters and the actual exposure of human consumers depends, to a very large extent, on the degree of equilibrium of the decay chain in the feed and through the metabolic process. The concentrations of 238U, 234U, 226Ra and 210Po (210Pb) in poultry feed supplements and in chicken meat (breasts, thighs) and organs (livers, spleens, gizzards) as well as in eggs were determined. From the results, the transfer coefficients of U and Po in chicken meat and in eggs were calculated. The effective dose equivalent to the Israeli population due to the consumption of poultry products which accounts for approximately 70% of all meat consumed in Israel is assessed to be 0.04 mSv y-1.