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PubMed1983

Quantitative measurements of radioactive isotopes in human nasal secretion.

Four patients receiving an intravenous injection of 99mTc-pertechnetate were investigated concerning transfer of the radioisotope to the nasal secretion. The concentration of isotope in nasal secretion was in all patients found to be approximately 10 times higher than in blood. The results suggest an active transport mechanism in the glandular elements of the nasal mucosa and that they are important as source of nasal secretion during normal conditions.

Adult↗
PubMedDate not supplied

Intensity/frequency indicator for detection in space: the high values of the incident solar or laser optical radiation in comparison with the appropriate maximum permissible exposure.

The solar or laser optical radiation impact to humans in space depends on the intensity, on the exposure type (direct or indirect) & duration and on the matching of radiation wavelength to tissue characteristics. The main protection factor in space is the application of exposure limits. This paper describes the main biological optical interaction parameters, the optical exposure hazards and the development of a small active lightweight indicator, with output beeper rate depended to the ratio of optical irradiance/exposure limit. The indicator may be used as warning element on the side of helmets, goggles, spectacles, etc, with low power consumption. Electronically the indicator is an intensity/frequency converter, based on the value of the ratio of exposure/exposure limits, with audio & light beepers like the indication output of the ionizing (radioactive) radiation monitors.

Electronics↗
PubMedDate not supplied

Pulmonary blood volume: correlation of equilibrium radionuclide and dye-dilution estimates.

In fifteen prospective patients with aortic stenosis undergoing transseptal cardiac catheterization, dye-dilution and count-based estimates of pulmonary blood volume (PBV) were performed. Three radionuclide methods were evaluated. Two were based on electrocardiogram (ECG)-gated imaging of the thorax, where pulmonary counts (PC) were corrected for frame-time, venous radioactivity, and either (1) the number of processed heart beats or (2) the total duration of acquisition. The third method involved ungated frame mode acquisitions, where PC were corrected for the duration of acquisition and the venous activity. PC (per channel element) were derived from manual assignments of the right lung. All methods correlated well with standard dye-dilution techniques (r greater than 0.82), though at greater volumes it was clear that count-based methods underestimated the dye-dilution values. In five acutely instrumented, anesthetized dogs, radionuclide (ungated formula) and dye-dilution estimates of PBV were made during multiple interventions (19 data points). The five control count volumes as well as the 14 separate intervention points correlated well (r greater than 0.89). It is concluded that PC from equilibrium blood pool images reflect PBV and that induced changes in PC can be utilized as a reflection of changes in PBV.

Adult↗
PubMed1984

The effect of chloroquine on lysosomal prolactin receptors in rat liver.

PRL receptors have been previously identified in purified rat liver plasma membrane and Golgi vesicle preparations. In this study, we report on PRL receptors located in highly purified lysosome preparations. These lysosomal PRL receptors were characterized using Scatchard analysis and compared to other intracellular and cell surface receptors. We have identified two classes of lysosomes. Lighter lysosome-like vesicles, which are greatly enriched in acid phosphatase activity (the marker enzyme of lysosomes), contain a great deal of binding activity. This PRL binding was only slightly increased by pretreatment of animals with the lysosomotropic agent chloroquine. In contrast, mature lysosomes showed very little binding activity in control animals, but chloroquine treatment increased binding 7- to 8-fold in these mature lysosomes. We suggest that the lysosome-like structures are immature lysosomes (namely prelysosomes) toward which the hormone-receptor complex is internalized: they appear to bear little proteolytic activity. These structures could play a role in PRL receptor recycling. Lysosomal PRL receptors showed curvilinear Scatchard plots, in contrast to plasma membrane and Golgi counterparts, which were linear over the same range of hormone concentrations. The high affinity site in lysosomes had a Kd comparable to the cell surface and Golgi receptors. The number of binding sites per mg protein in prelysosomes and lysosomes was 3 times greater than that in the homogenate, but Golgi preparations were 3 times as rich as lysosomes. The great number of PRL receptors in prelysosomes could be attributed, in large part, to the low affinity sites. The internalization of PRL into rat liver was examined after in vivo injection of [125I]iodoovine PRL. The labeled hormone was found initially in the plasma membrane fraction, after which it localized preferentially in the Golgi fraction, with maximum incorporation 15 min postinjection. Substantial radioactivity was observed in both classes of lysosomes (L-1 and L-2). In contrast to the Golgi fraction, maximum incorporation of [125I]iodoovine PRL in lysosomes occurred at 30 min. This suggests either that during internalization, PRL first reaches Golgi elements and is then transferred to the lysosomal compartment, or that there are two independent pathways of internalization, one rapid toward the Golgi complex (may be a path of receptor recycling) and the other toward lysosomes (probably leading to receptor degradation).

Acid Phosphatase↗
PubMed1980

A cloned chicken DNA fragment includes two repeated DNA sequences with remarkably different genomic organizations.

The presence of both single copy sequences and repeated DNA sequences with a broad range of repetition frequency is a hallmark of the eukaryotic genome. The advent of recombinant DNA technology has made it possible to isolate cloned DNA fragments that encompass two or more DNA sequences with different repetition frequencies. This provides the first opportunity to investigate the structural relationships in the genome of DNA of the different repetition frequency classes in a thorough and systematic way. A cloned fragment of the chicken genome containing two different repeated DNA sequences has been used for this purpose. By hybridization of radioactive restriction fragments of the cloned DNA to filter-bound restriction fragments of total chicken DNA, it has been determined that the 5.5-kilobase inserted DNA in this clone contains a copy of each of two long, repeated DNA sequence elements with different repetition frequencies. These two repeated DNA sequences have very diverse arrangements in the chicken genome. The results establish that, in addition to the interspersion of single copy and repeated DNA sequences in the chicken genome, repeated DNA sequences with very different structural characteristics can be interspersed with one another. Thus, the chicken genome is a complex network of related sequences in which some members of a family of repeated DNA sequences are associated with other, nonhomologous repeated DNA sequences, while other members of the same family are flanked by single copy DNA.

Animals↗
PubMed2005

Retention and phytoavailability of radioniobium in soils.

Radioniobium is present in long-lived nuclear waste as a result of the activation of zirconium pellets associated with the nuclear fuel. The behaviour of niobium (Nb) in the environment and especially its fate in the soil-plant system has not been thoroughly investigated so far. In safety assessment of French long-lived nuclear waste disposal, data concerning the mobility and the bioavailability of Nb in soils are needed as well as general trends of its fate in the specific environment around the site of French underground research laboratory. Therefore, we investigated the mobility of 95Nb in three different soils typical of the area of north-eastern France and its uptake by two plants, rye grass (Lolium perenne L.) and winter wheat (Triticum aestivum L.). Soil:solution distribution of 95Nb was observed in 1:10 batch experiments with deionized water for a 3-day period. Results showed that K(d) values were high (in the order of 10(3) L kg(-1)) and were still significantly increasing after 3 days. A mathematical model, fitted to describe the decrease of the radioactivity after 3 days, is proposed to calculate sorption ratios--SR--(rather than K(d) values as equilibrium was not reached) over longer periods. Soil-to-plant concentration ratios (CR) were measured in shoots and roots of the two plants after cultivation on two soils spiked with (95)Nb (406kBqkg(-1)). Soil-to-root dry weight CR were high (0.30-1.52) and could probably be due to efficient uptake into the roots. However, no transfer of Nb to plant shoots was detected in any of the soils. Nb is thus a rather immobile element in soils and its transfer to plants seems limited to underground parts. It would therefore tend to accumulate in surface horizons of soils in case of long-term continuous surface release.

Biological Availability↗
PubMed1994

Application of nuclear analytical techniques using long-life sealed-tube neutron generators.

The new range of sealed-tube neutron generators developed by SODERN appears to be appropriate for the industrial environment. The main characteristics are the high emission stability during the very long lifetime of the tube, flexible pulsed mode capability, safety in operation with no radiation in "off" state, and the easy transportation of equipment. Some applications of the neutron generators, called GENIE, are considered: high-sensitivity measurement of transuranic elements in nuclear waste drums, bulk material analysis for process control, and determination of the airborne pollutants for environmental monitoring.

Air Pollutants, Radioactive↗
PubMed2005

Thorium uptake by wheat at different stages of plant growth.

Data on biogeochemistry of thorium are rather limited. So far little is known about toxic effects of small amounts of the radionuclide on higher plants. In this study the uptake of thorium by wheat seedlings was measured by greenhouse experiments. Germination of wheat seeds for 6 days in the presence of thorium resulted in accumulation of the metal in all parts of the seedlings. When the Th-rich seedlings were transferred to normal soil and were grown there further for 7 days, Th concentrations in roots and leaves decreased significantly (in leaves the Th content decreased up to the level of Th in the control plants). In seeds, however, Th content remained unchanged. An increase of Th content in roots and seeds was also observed as a result of addition of thorium to soil but in this case the concentration of Th in leaves did not change. The accumulation of Th in plants affected the uptake of other elements including essential macro-nutrients. The most strongly affected part of the plants was leaf.

Germination↗
PubMedDate not supplied

Radionuclide production at the Russia State Scientific Center, RIAR.

Radionuclide production capabilities of the Russia State Scientific Center, the Research Institute of Atomic Reactors (RIAR) are reviewed. Radionuclides routinely produced are as follows: transplutonium elements 243Am, 244-248Cm, 249Bk, 249Cf, 252Cf and high specific activity radionuclides 153Gd, 33P, 113,119mSn, 188W, 63Ni, 55,59Fe, 51Cr, 54Mn, 89Sr. Other HSA radionuclides (133Ba, 65Zn, 124Sb, 45Ca, 60Co, 192Ir, 169Yb, 170Tm, 75Se) are also available from RIAR. Besides radioactive preparations RIAR produces ionising neutron (252Cf), gamma (60Co, 192Ir, 75Se, 153Gd) and alpha (244Cm) sources for medicine, industry and research. A short description of the technology developed is presented.

Nuclear Reactors↗
PubMed2002

Ligand-induced heterodimerization between the ligand binding domains of the Drosophila ecdysteroid receptor and ultraspiracle.

The insect ecdysteroid receptor consists of a heterodimer between EcR and the RXR-orthologue, USP. We addressed the question of whether this heterodimer, like all other RXR heterodimers, may be formed in the absence of ligand and whether ligand promotes dimerization. We found that C-terminal protein fragments that comprised the ligand binding, but not the DNA binding domain of EcR and USP and which were equipped with the activation or DNA binding region of GAL4, respectively, exhibit a weak ability to interact spontaneously with each other. Moreover, the heterodimer formation is greatly enhanced upon administration of active ecdysteroids in a dose-dependent manner. This was shown in vivo by a yeast two-hybrid system and in vitro by a modified electromobility shift assay. Furthermore, the EcR fragment expressed in yeast was functional and bound radioactively labelled ecdysteroid specifically. Ligand binding was greatly enhanced by the presence of a USP ligand binding domain. Therefore, ecdysteroids are capable of inducing heterodimer formation between EcR and USP, even when the binding of these receptor proteins to cognate DNA response elements does not occur. This capability may be a regulated aspect of ecdysteroid action during insect development.

Animals↗
PubMed1989

Three example applications of optimization techniques to Department of Energy contractor radiation protection programs.

Six numerical examples of optimization of radiation protection are provided in the appendices of International Commission on Radiological Protection (ICRP) Publication No. 37 (1983). In each case, the calculations were based on well-defined parameters and assumptions. In this paper, we examined three different numerical examples that were based on empirical data and less-certain assumptions. In the first example, the optimum sampling frequency for a typical 3H bioassay program was found to be once every 2 mo. However, this result depended on assumed values for several variables that were difficult to evaluate. The second example showed that the optimum frequency for recalibrating a group of "cutie pie" (CP) ionization chamber survey instruments was once every 85 d. This result depended largely on the assumption that an improperly operating CP instrument could lead to a serious overexposure. In the third example, one continuous air monitor (CAM) was determined to be the optimum number in a workplace at a Department of Energy (DOE) Pu facility. The optimum location of the CAM was determined from past glove-box release studies. These examples demonstrated that cost-benefit analysis of individual elements of radiation protection programs can be useful even if limited data are available.

Air Pollution, Radioactive↗
PubMed1992

Concentrations of radionuclides of size fractionated fly-ash emissions from a thermal power plant using Taiwan coal.

Coal, fly ash and bottom ash samples were taken from a 300-MWe coal-fired power plant with a daily coal consumption of 2400 tons. A high volume sampler coupled with several mesh testing sieves was used to separate fly ash samples into different size fractions. Determination of the concentrations of 40K, 238U, 226Ra, 210Pb, 210Po, 228Th and 228Ra was carried out either by gamma or alpha spectrometry. For elements volatilized during combustion, their radionuclide concentrations decrease with increasing particle size. The enrichment factors for all radionuclides mentioned above were studied. Their values range from 31.0 for 210Po to 2.2 for 228Ra. Of all radionuclides studied, 210Po and 210Pb are the most volatile elements; therefore, an increase in the natural radiation level should first be indicated by an increase in these two nuclides.

Air Pollutants, Radioactive↗
PubMed1988

Isolation of a vesicular intermediate in the cell-free transfer of membrane from transitional elements of the endoplasmic reticulum to Golgi apparatus cisternae of rat liver.

Preparations enriched in part-smooth (lacking ribosomes), part-rough (with ribosomes) transitional elements of the endoplasmic reticulum when incubated with ATP plus a cytosol fraction responded by the formation of blebbing profiles and approximately 60-nm vesicles. The 60-nm vesicles formed resembled closely transition vesicles in situ considered to function in the transfer of membrane materials between the endoplasmic reticulum and the Golgi apparatus. The transition elements following incubation with ATP and cytosol were resolved by preparative free-flow electrophoresis into fractions of differing electronegativity. The main fraction contained the larger vesicles of the transitional membrane elements, while a less electronegative minor shoulder fraction was enriched in the 60-nm vesicles. If the vesicles concentrated by preparative free-flow electrophoresis were from material previously radiolabeled with [3H]leucine and then added to Golgi apparatus immobilized to nitrocellulose, radioactivity was transferred to the Golgi apparatus membranes. The transfer was rapid (T1/2 of about 5 min), efficient (10-30% of the total radioactivity of the transition vesicle preparations was transferred to Golgi apparatus), and independent of added ATP but facilitated by cytosol. Transfer was specific and apparently unidirectional in that Golgi apparatus membranes were ineffective as donor membranes and endoplasmic reticulum vesicles were ineffective as recipient membranes. Using a heterologous system with transition vesicles from rat liver and Golgi apparatus isolated from guinea pig liver, coalescence of the small endoplasmic reticulum-derived vesicles with Golgi apparatus membranes was demonstrated using immunocytochemistry. Employed were polyclonal antibodies directed against the isolated rat transition vesicle preparations. When localized by immunogold procedures at the electron microscope level, regions of rat-derived vesicles were found fused with cisternae of guinea pig Golgi apparatus immobilized to nitrocellulose strips. Membrane transfer was demonstrated from experiments where transition vesicle membrane proteins were radioiodinated by the Bolton-Hunter procedure. Additionally, radiolabeled peptide bands not present initially in endoplasmic reticulum appeared following coalescence of the derived vesicles with Golgi apparatus. These bands, indicative of processing, required that both Golgi apparatus and transition vesicles be present and did not occur in incubated endoplasmic reticulum preparations or on nitrocellulose strips to which no Golgi apparatus were added.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphate↗
PubMed2002

Effect of a chayotte (Sechium edule) extract on the labeling of red blood cells and plasma proteins with technetium-99m: in vitro and in vivo studies.

Sechium edule (chayotte) is used as food or as medication in popular medicine. The labeling of blood elements with technetium-99m (99mTc) has been altered by drugs (synthetic and natural). Some authors have reported biological effects concerning the chayotte. We have evaluated the influence of chayotte extracts (macerated and infusion) on the labeling of blood elements with 99mTc. In vitro study, blood was incubated with the extracts, (6.25, 12.5, 25, 50 and 100% v/v). In in vivo study, the animals were treated with the extracts (100% v/v), as drinking water (15 and 60 days) and samples of blood were withdrawn. The blood samples were incubated with stannous chloride and with 99mTc. Plasma (P) and blood cells (BC) were isolated, also precipitated with trichloroacetic acid and soluble (SF) and insoluble fractions (IF) separated. There was a (p < 0.05) decrease in the radioactivity in BC, IF-BC and IF-P with the infusion (100%) and a slight decrease in the uptake of 99mTc by BC and a strong decrease in the fixation in IF-P with the macerated when the extracts were administrated in vivo (15 days). In 60 days, there was a decrease in BC (98.77 to 53.53%), in IF-BC (90.36 to 21.20%) and in IF-P (77.20 to 11.01%). In vitro study no alterations on the labeling of blood elements were found, however, we have found alterations on the fixation of 99mTc in the in vivo study, probably, due to the metabolization of chayotte capable to induce the generation of active metabolites.

Animals↗
PubMed2005

Radionuclide and chemical concentrations in mineral waters at Saratoga Springs, New York.

A project to characterize the radionuclide and chemical components in natural spring waters in the vicinity of Saratoga Springs, New York (USA) has been completed. As a result of the measured radionuclide and chemical content, eight springs were labeled as mineral waters, whereas three springs contained very low concentrations of these components. The mineral waters were highly enriched in alkaline and alkaline-earth elements, as well as chloride ions. Three isotopes of radium ((224)Ra, (226)Ra, (228)Ra) were detected in the mineral waters and reached concentrations of 1, 20, and 2 Bq/L, respectively. Overall, the (226)Ra isotope constituted about 80% of the total radioactivity measured in the water samples. Dissolved uranium concentrations in the mineral waters were very low (mean approximately 50 mBq/L).

Environmental Monitoring↗
PubMed1986

Development of the hypothalamic serotoninergic system during ontogenesis in rats. Immunocytochemical and radioautographic study.

The development of the hypothalamic serotoninergic system has been studied in rats from the 14th fetal till the 9th postnatal day. Serotoninergic elements were detected with immunocytochemistry using antiserum to serotonin (5-HT) and radioautography following the injections of [3H]5-HT into the cerebral ventricles. Immunocytochemistry failed to recognize hypothalamic 5-HT neurons either in fetuses or in neonatal rats. Conversely, radioautography demonstrated sparse radioactively labeled cells, undifferentiated in appearance, at the 16th and 18th fetal days. Moreover, at the 18th fetal day an accumulation of radioactively labeled typical neurons appeared in the suprachiasmatic region. By the 9th postnatal day, practically all radioactively labeled cells looking like highly differentiated neurons were concentrated in the dorsomedial nucleus. As to nerve fibers, a small number of 5-HT-immunoreactive axons arising from the raphe nucleus were first detected in the hypothalamus at the 16th fetal day. Two days later, both 5-HT-immunoreactive and radioactively labeled fibers became widely distributed through the hypothalamus with especially high concentrations in and around the optic chiasma. By the 9th postnatal day, the frequency of 5-HT fibers increased considerably both in the anterior and middle hypothalamus. Some 5-HT fibers were apposed to unlabeled neurons and others abutted on the capillaries either in the organum vasculosum of the lamina terminalis or in the median eminence. The present morphologic study suggests that during the perinatal period the hypothalamic 5-HT system becomes developed enough to be involved in the regulation of some neuroendocrine functions.

Animals↗
PubMedDate not supplied

[Sentinel lymph-node biopsy for breast cancer. Analysis of 235 cases and review of the literature].

Sentinel lymph-node biopsy for breast cancer has been rapidly adopted in clinical practice. At the present time few prospective randomised studies exist, the false negative rate is variable and its role with regard to prognosis is not well known. The aim of this study was to evaluate the elements of sentinel lymph-node biopsy that have yet to be clearly defined, by reference to the literature and our own experience. From September 1999 to July 2005, we considered 235 consecutive patients undergoing sentinel lymph-node biopsy. We used the radioactive tracer in 143 cases, and the radiotracer combined with vital blue dye in 89 cases. Vital blue dye was used alone in only 3 cases. In 224 cases the sentinel lymph-node biopsy was performed in a single session, using frozen sections to evaluate the sentinel node. The identification rate obtained was 97.9% with the radiotracer, 100% with the combined procedure and 66.7% with vital blue alone. The sentinel node proved positive in 52 cases. The frozen sections correctly predicted the positive result of the definitive histopathological analysis in 26 cases and correctly predicted a negative result in 172. We discuss the indications and methods of sentinel lymph-node biopsy, analysing our own data and those reported in the literature.

Adult↗