Transport of lanthanides in milk into suckling rats.

The aim of this paper was to examine the transport of lanthanides in milk of contaminated rats into their sucklings and the retention of lanthanides in the sucklings. The research involved 55 female Wistar rats contaminated in the period of lactation and their offspring (400 infant rats). The study showed that in the period of lactation the transport in milk from the mother to the offspring of the lanthanide radionuclides under examination (144Ce, 147Nd, 152Sm, 155Eu and 160Tb) increased with their mass numbers: CE < Nd < Sm < Eu < Tb, and varied from 0.01% for 144Ce to 17.7% for 160Tb of the administered dose per litter. It was demonstrated that lanthanides were not absorbed from the digestive tract of sucklings because they were not detected beyond its area. Because of its highest concentration in milk 160Tb was chosen for further investigation of the kinetics of transport in individual segments of the digestive tract. The model for determining the function of lanthanide retention in separate parts of the digestive tract of sucklings and the half life of effective accumulation and elimination of 160Tb in the whole organism as well as in individual segments of the digestive tract are presented. Terbium-160 accumulation in sucklings increased whereas its elimination decreased with the age of the infant. No significant differences in 160Tb specific activity in stomach, and small and large intestines were observed in sucklings one to 21 days old. Biological half lives for retention of the contaminated milk were as follow: 0.25 +/- 0.021 per day for the stomach, 0.92 +/- 0.12 per day for the small intestine and 5.03 +/- 0.22 per day for the large intestine. The data obtained can be used in the evaluation of the doses absorbed from 160Tb and from other lanthanide radionuclides that are nonabsorbable from the digestive tract, as well as in estimation of the radiation risk to the offspring of mothers contaminated in the period of lactation.

The effect of toxic doses of lanthanum and cerium on the placental barrier and the blood/organ barrier in mice after intravenous injection of these elements.

In earlier studies the toxicity of the lanthanides was determined on the basis of the LD50/30 value, increase of serum ornithine carbamoyltransferase activity, and the degree of passage of the lanthanides to the fetuses and milk. The purpose of the present work was to investigate the effects of toxic doses of lanthanum and cerium on the function of the placental barrier and the blood/organ barrier in mice using substances of known molecular weight labelled with radionuclides (14C-aminoisobutyric acid--AIB, 3H-thymidine and 125I-albumin). Increased uptake of 14C-AIB and 3H-thymidine was demonstrated in the liver, spleen and placenta of mice after toxic doses of La and Ce indicating disturbances in the function of the blood/organ barrier (liver, spleen, placenta) due to damage to the vascular endothelium or cell membranes. No disturbances were shown in the function of the placental barrier (which would have caused increased passage of these markers to the fetus), and rupture of the cell membranes in the studied tissues was not demonstrated (it would have caused increased passage of 125I-albumin, a macromolecular compound) in any of the studied organs in mice.

Estimation of I131 doses absorbed by the thyroid in the period from May to June 1986.

In a randomly selected group of subjects the uptake of iodine radioisotopes was measured over the thyroid in the period May 6-23, 1986. From the obtained results the doses were estimated which were absorbed from April 28, 1986 until the time of complete disappearance of I131 from the thyroid. The highest dose of radiation absorbed from I131 by the thyroid was found in the youngest group (children aged 5 to 12 years) and it was 227.8 mGy (about 23 rads).

The metabolism of 4-iodantipyrine--I125 (RIAP) in rat organism after intravenous injection.

Radioactive antipyrine labelled with I125 (RIAP) is used in radioisotope diagnostic methods for determination of the total water content of the organism, and cerebral and cardiac blood flow. The purpose of this study was to investigate RIAP metabolism in rats after intravenous administration. The distribution, excretion and passage with milk to the newborn animals were studied. Electrophoresis of the urine of the rats treated with this radioisotope was done as well. A rapid accumulation of the radioisotope in the thyroid was observed (the T 1/2 value was about 4 hours, and the greatest accumulation of RIAP was after 15 hours). The biological time of RIAP elimination from the thyroid was 5 days. I125 concentration in other organs was below 1% of the injected dose. Excretion was mainly with urine in three phases. In the urine of the rats two I125-containing fractions were found (a iodide fraction and an unidentified fraction). RIAP administration to lactating females caused passage of between 10 and 20% of the administered dose to pass to the newborns with milk. RIAP administration to pregnant rats raised this proportion by several per cent. Thyroid blockade with potassium iodide had no effect on RIAP passage with milk to the newborns. These results suggest a rapid loss of iodine from RIAP after intravenous injection.

Regeneration in small intestine following exposure to X-radiation and neutron beam as estimated in the light of changes in alkaline phosphatase activity and degree of 3H-thymidine incorporation into cells in intestinal crypts.

Swiss mice were irradiated with X-rays (5, 7 and 9 Gy) and neutrons (3 and 5 Gy) determining the degree of 3H-thymidine incorporation into the cells in the intestinal crypts, alkaline phosphatase activity in intestinal homogenate and serum, and radiation-induced leucopenia. It was shown that damage to the cells in intestinal crypts depends on the dose and type of radiation. More radiation-resistant cells covering the intestinal villi showed a significant inhibition of alkaline phosphatase activity at high radiation doses. Changes in intestinal alkaline phosphatase activity were reflected also by changes in its level in the serum where its dependence on the dose of radiation was evident also.

The effect of X-radiation on the process of lung clearance after inhalation of bacteria labelled with 3H-thymidine.

The respiratory tract is cleared very effectively from the inhaled particles by the ciliated bronchial epithelium, secretion of secretory cells, and specialized phagocytic cells. Within 4 hours about 80% of the inhaled microorganisms are destroyed in the respiratory tract. The rate of removal of the micro-organisms from the lungs and their destruction may play a very important role in preventing infection development. The aim of the present experiment was to study the adverse effect of ionizing radiation on the mechanisms involved in cleaning the lungs. Wistar rats were used for this purpose. They received a dose of 500 cGy. The irradiated animals and the control non-irradiated ones inhaled in a PIANO IV apparatus Staphylococcus epidermidis labelled with tritiated thymidine. Determining the clearance of the bacteria from the bronchial tree and pulmonary tissue an impairment of the mechanisms clearing the lungs in the irradiated group was demonstrated. The effect of radiation may be related to a damage to the alveolar macrophages which are principally responsible for destroying bacteria at the level of pulmonary alveoli. The relatively radiation-resistant ciliated epithelial bronchial cells may have their efficiency reduced owing to disturbances in mucus secretion by the secretory cells.

Injury and regeneration in rat small intestine cells after exposure to neutrons.

The degree of damage to intestinal crypt epithelium and the process of its regeneration was studied after exposure to neutrons in rats. The aim of the study was an evaluation of the degree of impairment of proliferation of the stem cells in the intestinal crypts following exposure to one dose of 4 Gy, to two doses of 2 Gy each with an interval of 24 hours between them, and to one dose of 4 Gy administered together with a stimulator of leucopoiesis--Leukogen. The animals were administered 3H-thymidine and the per cent of its incorporation was determined. It was found that administration of the divided dose or of one total dose but together with the regeneration-stimulating agent prevented profound epithelial changes. The rate of return to normal incorporation was similar in the rats given the divided dose and in those receiving Leukogen.

Leucogen effect on postradiation injury of intestinal crypts.

Leucogen effect on the regeneration of cells in intestinal crypts was examined after a sublethal dose of 600R of gamma radiation. The animals were given 3H-thymidine and the per cent of its incorporation was determined. A stimulating effect of Leucogen was observed on the regeneration of cells in the intestinal crypts.

Effect of various doses of cerium on the serum level of ornithine-carbamyltransferase in rats.

The relationships between different cerium doses administered intravenously as CeCl3 and the mortality of rats and their serum OCT level were studied. The LD50/30 value for cerium given intravenously to rats was 5.56 mg Ce/kg. A directly proportional correlation was demonstrated between intravenously administered Ce doses and the serum OCT level above a threshold dose.

Modifying effect of commercially available stannous pyrophosphate (PYRO-Sn) on the tissue affinity of 99mTc pertechnetate.

Investigations were performed to examine the conditions required for in vivo labelling of red blood cells (RBCs) with 99mTc after injection of stannous pyrophosphate. It was found that good in vivo labelling of RBCs is possible and that the efficacy of this procedure is high. The highest concentration of 99mTc in the blood occurred in the first 2 h after pertechnetate injection, and the optimum time between stannous pyrophosphate and pertechnetate injection ranged from 10 to 30 min.

Cardiac studies using red blood cells labeled with Tc-99m in vivo with single intravenous injections--first pass technique, gating and blood pool scanning.

The investigations were carried out in 51 patients with different cardiovascular diseases using a gamma camera coupled to a computer. Pyrophosphate (Sn) injection followed by technetium-99m injection were administered through only one puncture of an antecubital vein. Tc-99m was given as a bolus and its passage through the cardiac cavities was recorded and ejection fraction and wall motion of left ventricle were estimated. It was observed that 10-30 min after Tc-99m injection a steady activity Tc-99m-labeled RBCs was maintained in the vascular bed which made possible evaluation of the motility of cardiac walls by the gating technique. Presence of labeled RBCs also permitted blood pool scans and spleen scans to be obtained. Cases investigated by this method for pericardial effusion and splenomegaly are described for illustration.

Serum ornithine carbamoyltransferase (OCT) in rats poisoned with lanthanum, cerium and praseodymium.

Serum ornithine carbamoyltransferase (OCT) in rats poisoned with lanthanum, cerium and praseodymium. Acta Physiol. Pol., 1977, 28 (6): 589-594. The serum ornithine carbamoyltransferase in relation to doses of lanthanum, cerium and praseodymium, administered intravenously as chlorides, was investigated. A directly proportional relationship was found between the doses of these compounds and the serum enzyme level in rats. The lowest doses at which a rise in the serum OCT level occured were determined. They were: lanthanum - 0.75 mg/kg of body weight, cerium - 1.5 mg/kg, and praseodymium - 3 mh/kg. A decreasing toxicity of these elements with increasing value of atomic number was observed.

Effects of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) derivatives on penetration of ytterbium-169 and cerium-144 into the rat offspring.

Effects of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) derivatives on penetration of ytterbium-169 and cerium-144 into the rat offspring. Acta Physiol. Pol., 1976, 27 (2): 175-181. Penetration of radioactive ytterbium-169 and cerium-144 into fetuses was determined at the end of pregnancy and penetration into the organism of suckling rats was studied during feeding with the milk of exposed mothers when EDTA or DTPA derivatives were being administered. Injection of ytterbium-169 as a complex with EDTA or DTPA or injection of Na2Ca EDTA or Na3Ca DTPA 1h after administration of cerium-144 to mothers reduced penetration of both radionuclides into offsprings in relation to the animals receiving no complex compounds. It was observed that the action of DTPA was stronger than that of EDTA. Passage of ytterbium with milk and across the placenta was greater than the passage of cerium.