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Results for “Potassium Radioisotopes”

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At least 19 recordsLinked to original sources
PubMed1990

[Radioactivity of fodder mixtures for poultry and swine].

The investigation was conducted to determine the radioactivities of fodder mixtures and their components for poultry and swine. The total radioactivity, concentrations of potassium, potassium radioisotopes radium and thorium in 273 fodder mixture samples for poultry, 131 fodder mixture samples and concentrates for swine, and 915 component samples of the mixtures were estimated. The radioactivities of fodder mixtures for poultry, swine, and protein concentrates ranged from 212.0 (DKM-2) to 269.0 Bq/kg (DKA-starter), from 206.0 (PT-1) to 233.0 (PP-prestarter), and from 444.0 (KT-1) to 557.0 Bq/kg (Provit), respectively. As to the components of fodder mixture, the radioactivities ranged from 18.0 (fodder phosphate) to 1104.0 Bq/kg (fodder yeasts). The potassium concentrations in fodder mixtures for poultry ranged from 0.82 g/100 g (DKA-starter) to 0.62 g/100 g (KB-1); for swine ranged from 1.97 g/100 g (Provit) to 0.63 g/100 g (PT-1). The highest concentration of potassium was found in fodder yeasts (3.85 g/100 g), and the lowest one in fodder phosphate (0.01 g/100 g). The analysis of the data showed that the radioactivity of the mixtures and their components was mostly conditioned by radiopotassium and revealed correlations between the radioactivities and the total concentrations of potassium. The contamination with the natural radioelements (potassium, radium, thorium) as well as their limited absorption by the gastrointestinal tract, their metabolism in organism, and their radiotoxicological characteristics do not create radiological threat to animals.

Animal Feed↗
PubMed2003

Nutritional and radiological impact of dietary potassium on the Pakistani population.

The nutritional status of dietary potassium and the radiological impact of its isotope (40)K were estimated for the Pakistani population. Potassium concentration was determined in dietary samples by atomic absorption spectrometry. An average potassium concentration was 4.54+/-0.89 mg/g, which leads to potassium dietary intake of 2.69+/-0.54 g/day and the radiological hazard due to (40)K activity was 79.94 Bq/day. The annual and lifetime effective doses calculated for the reference Pakistani man weighing 64 kg due to measured activity of (40)K were found to be 1.65 x 10(-4) Sv y(-1) and 8.27 x 10(-3) Sv, respectively. Measured data showed that the potassium concentration in the Pakistani diet is adequate and safe according to international standards.

Adult↗
PubMed1999

A two-compartment model for zinc in humans.

The oral absorption of zinc, from a test meal of minced beef, mashed potatoes and peas, have been measured in 19 healthy adults using the radiotracer 65Zn. The oral absorption, expressed as a percentage of the administered dose, was 20 +/- 5% (mean +/- 1 SD) in good agreement with previous results. In a subset of 9 subjects, tracer retention in whole body and whole blood was followed out to one year. The data were fitted to a simple two compartment model yielding total body zinc (TBZn), the zinc content in each of the 2 compartments and zinc turnover. The TBZn values ranged from 15.5 to 35.9 mmol while zinc turnover ranged from 0.043 to 0.073 mmol/d in keeping with results reported for significantly more complicated compartmental models applied to more comprehensive 65Zn tracer data sets. Additionally, TBZn correlated well with total body potassium, a measure of lean body mass, measured by whole body counting of the naturally-occurring potassium radioisotope, 40K. The zinc content of the more rapidly turning over compartment ranged from 3.2 to 5.6 mmol in reasonable agreement with exchangeable zinc pool estimations reported for short term studies using stable zinc isotopes. Therefore, the simple dataset and model employed in the present study yielded information on the short- and long-term behaviour of zinc compatible with both more complex radiotracer studies and analytically more demanding stable isotope studies.

Administration, Oral↗
PubMed1977

Performance parameters of the Hamburg 4 pi whole body radioactivity detector.

Large 4 pi whole body counters allow the use of very low doses of radioactivity in medical research and in routine diagnosis of patients. The electronics of the 4 pi whole body counter in Hamburg (HAMCO) have recently been updated. The detector contains 1360 I of liquid organic scintillator. Experiments combined with extensive computer simulations yielded quantitative information for whole body counters and comparable systems, (1) about physical parameters such as detection efficiency, energy resolution and background count rates which are important for practical performance, and (2) concerning the optical properties of the large volume scintillation counters employed here; these are of interest for the construction of future detectors of related types.

Cesium Radioisotopes↗
PubMed1975

Radioisotopic measurements of coronary blood flow.

This review has presented a critical evaluation of current methods used in measurement of total and regional blood flow. Measurement of total coronary blood flow furnishes little evidence of pathological processes within the coronary vascular system. However, in conjunction with coronary vasodilators, measurement of total coronary blood flow may indicate the presence of coronary artery disease. Difficulties inherent in the determination of regional coronary blood flow lie primarily in defining clearance slopes and in the presence of accidental counts. More promising are methods using scintigraphs obtained with radioactive particles injected into the coronary artery. However, these procedures do not measure flow, only flow distribution. A procedure for measuring regional uptake of positron emitters by coincidence counting has been described; the method possesses definite advantages over other procedures, since it is noninvasive and appears to have good resolution. However, the method is dependent on higher decay density which necessitates the use of nuclides with a short half-life (e.g., 81rubidium).

Animals↗
PubMed1986

Ionizing radiation promotes protozoan reproduction.

This experiment was performed to determine whether ionizing radiation is essential for maximum growth rate in a ciliated protozoan. When extraneous ionizing radiation was reduced to 0.15 mrad/day, the reproduction rate of Tetrahymena pyriformis was significantly less (P less than 0.01) than it was at near ambient levels, 0.5 or 1.8 mrad/day. Significantly higher growth rates (P less than 0.01) were obtained when chronic radiation was increased. The data suggest that ionizing radiation is essential for optimum reproduction rate in this organism.

Background Radiation↗
PubMed1993

Potassium loss from skeletal muscle during exercise in man: a radioisotope study.

Muscle potassium (K+) content decreases during exercise. Previous studies, in humans, have used measurements of arteriovenous plasma potassium concentration differences (AV delta[K+]) and/or muscle biopsy to measure the loss of muscle K+ during exercise. In the current study a non-invasive method was developed to measure skeletal muscle K+ before and after exercise, using an isotope of K+, potassium-43 (43K+). Twelve subjects performed single-leg extension exercise for 2 h at 50% of their maximum predicted heart rate. The level of radioactivity from the quadriceps femoris was determined before exercise and during two periods post-exercise. After correction for counts arising outside the exercised muscle, we estimate a decrease in muscle K+ content of 3.2 +/- 1.55% (mean +/- S.E.M.) following exercise. The muscle K+ was not restored following 75 min of recovery. The decrease in muscle K+ following exercise in our study is considerably less than that suggested by previous studies using AV delta[K+] measurements but not so dissimilar from results obtained using muscle biopsy. We conclude that a small but significant loss of K+ occurs following prolonged dynamic exercise, and that complete recovery of muscle K+ is slow.

Adult↗