Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RADIOACTIVITY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,711 records · Page 95Linked to original sources
PubMed1977

Effect of purification on the accumulation of radioactive gallium labeled leukocytes in abscesses.

In rabbits, autologous peripheral blood leukocytes labeled in vitro with 67Ga citrate have been purified in vitro by the processes of dialysis and cell washing to determine the effect of purification on the accumulation of the labeled cells in abscesses of the abdominal wall. Dialysis was found to be ineffective, but cell washing produced a population of labeled leukocytes that was essentially free of noncell bound radioactivity. The purification process minimally altered the recirculating capacity of the leukocytes but significantly enhanced the relative accumulation of radioactivity in the septic area. Thus, the use of an essentially pure population of labeled leukocytes should offer a significant potential in the definitive scintiscan demonstration of hidden abscesses.

Abscess↗
PubMed1996

Detection of cytokine mRNA-expressing cells in peripheral blood of patients with IgA nephropathy using non-radioactive in situ hybridization.

IgA nephropathy (IgA-N) is considered to be an immune-mediated disorder and several immunological abnormalities have been observed. In the present study, we optimized non-radioactive in situ hybridization and applied this technique to evaluate the degree of expression of various cytokine mRNAs in peripheral blood mononuclear cells (PBMC) taken from patients with IgA-N on cytospin preparation. Using this method, together with image analysis, we examined the expression of mRNA in cells which secrete cytokines, such as IL-2, interferon-gamma (IFN-gamma), IL-4, IL-5 and IL-6. The expression of these mRNAs was clearly observed in monocytes and lymphocytes at a single-cell level. Compared with healthy adults, the expression of IL-4 mRNA, IL-5 mRNA and IL-6 mRNA, but not IL-2 mRNA or IFN-gamma mRNA, was significantly enhanced. Our results indicate that non-radioactive in situ hybridization method is a powerful technique for analysis of cytokine mRNAs in PBMC at a cellular level. Our results also suggest that mRNA expression of IL-4, IL-5 and IL-6, produced by Th2 cells, is increased in patients with IgA-N. The abnormal regulatory process involved in cytokine expression may play an important immunopathologic role in IgA-N.

Adult↗
PubMed1995

Use of non-radioactive probes for mRNA detection by in situ hybridization: interests and applications in the central nervous system.

Non-radioactive probes for in situ hybridization (ISH) are now widely used to detect mRNAs in the central nervous system (CNS) using light and electron microscopy. Many different protocols for the detection of biotinylated or digoxigenin-labelled probes are now available. The advantages and inconveniences of the use of the non-radioactive probes are reviewed in the current work. These aspects are illustrated by some results from first-hand experience in the field of ISH to analyse gene expression and neuronal phenotypes in the hypothalamus and the basal ganglia. A very sensitive procedure for the simultaneous detection of two mRNAs with cRNA probes have been detailed and using in particular digoxigenin-labelled probes.

Animals↗
PubMed1995

A simple non radioactive method for detecting beta-thalassemia/hbe disease: application to prenatal diagnosis.

We have developed allele specific polymerase chain reaction (ASPCR) that allows rapid screening of the beta E-globin and common beta-thalassemia genes in Thailand. These non-radioactive methods are based on the amplification by the polymerase chain reaction of the beta E and beta-thalassemia specific DNA fragments using specific primers. With this approach, both heterozygote and homozygote for the disease could readily be identified on agarose gel electrophoresis of the amplified DNA. We have applied the method for a prenatal diagnosis of beta-thalassemia/HbE disease in a Thai family at the second trimester of pregnancy. The result obtained was comparable to that of conventional dot blot hybridization using radioactive probes. The simplicity, accuracy and non isotopic of the approach make it a highly promising method for a carrier screening and a prenatal diagnosis of this common disorder.

Alleles↗
PubMed1996

[Detection of rifampicin-resistant strains of Mycobacterium tuberculosis by a non-radioactive PCR-SSCP method].

PCR-SSCP method to detect genetic mutations in rpoB gene as a marker of rifampicin-resistance was developed by Telenti et al., and we have modified it applying non-radioactive PhastSystem for more practical use in the detection of rifampicin-resistance of Mycobacterium tuberculosis. PCR products amplified with the primers specific to rpoB gene using extracted DNA from 89 strains of M. tuberculosis were sequenced and the amino acid sequences were morphism was determined by the PhastSystem. The bands were stained by silver staining. Among 89 strains of M. tuberculosis, 43 were confirmed as rifampicin-resistant (RFPr) and 46 were rifampicin-sensitive (RFPs) by the culture on the drug-containing media. All of the 43 RFPr strains had one or more mutations in the DNA sequence of rpoB gene, while none of the RFPs strains had such mutations. However, by PCR-SSCP, only 20 out of 43 RFPr strains showed clear differences in the band pattern of electrophoresis from that of RFPs strains. Other 23 RFPr strains had only slight differences in the band pattern of the PCR-SSCP from that of RFPs strains. But it was noticed that the main bands of RFPr strains were distinguishable from the main bands of RFPs strains even their patterns were similar. Thus, it is possible to apply a non-radioactive PCR-SSCP for the detection of rifampicin resistance of M. tuberculosis with further improvement of the condition of gel electrophoresis or staining techniques.

Amino Acid Sequence↗
PubMed1977

Tissue distribution studies with radioactive manganese: a potential agent for myocardial imaging.

Manganese, a trace metal, is known to localize in mitochondria. Because mitochondria are abundant in heart muscle, the possible utility of radioactive manganese as a myocardial imaging agent was examined in 25 rats and six dogs. Myocardial uptake of Mn-54 in rats was found to exceed that of thallium-201; myocardium-to-blood ratios averaged 306:1 versus 48:1 for Tl-201. In the dog, uptake of Mn-54 by ischemic myocardium was reduced by 17-75% compared with normal myocardium. Thus, radioactive manganese appears promising as an intravenous myocardial imaging agent, and might be useful in studying the function of myocardial mitochondria by external imaging.

Animals↗
PubMed1996

The assessment of doses and effects from intakes of radioactive particles.

The behaviour of radionuclides after entry into the body and the radiation doses received by individual tissues depend on the chemical nature of the element, the physicochemical form of the intake, the radioactive half-life of the isotope and the type and energy of the emissions. Ingestion of radionuclides in insoluble particles will result in radiation doses being delivered to tissues of the gastrointestinal (GI) tract; other tissues will also be irradiated by nuclides with penetrating photons emissions (gamma) but doses may be largely confined to the GI tract for charged particle emissions (alpha, beta). Ingestion of more soluble forms will lead to greater absorption to blood and deposition in other tissues and therefore may result in greater doses to other tissues. Similar considerations apply to inhaled material and to the entry of radionuclides through cuts or wounds. For ingested materials, including particles, more information is needed on uptake and retention in intestinal tissues and consequent doses to sensitive cells, particularly for alpha emitters. There has been concern that the pattern of distribution of activity throughout irradiated tissues may influence the extent of damage, particularly for alpha emitters because of the localised deposition of energy and their greater relative biological effectiveness compared with beta/gamma emitters. Aggregation of activity has the potential to result in greater acute tissue damage and has been shown, for example, to result in focalised pneumonitis and fibrosis in the lung and ulceration of the skin. The main long-term effect of irradiation of tissues is the induction of malignant change, although hereditary disease may also be of concern following irradiation of the gonads. There are only limited data available to compare the effect on cancer induction of heterogeneous and homogeneous irradiation of tissues. However, the available information, for irradiation of the lung, skin or liver, indicates that in general nonuniform alpha irradiation from radioactive particles is no more hazardous, and may be less hazardous, than if the same activity is uniformly distributed.

Administration, Oral↗
PubMed1996

Rapid detection of factor V Leiden (FVQ506) by non-radioactive single strand conformation polymorphism (SSCP).

The transition G-->A at position 506 of the factor V gene is responsible for resistance to the anticoagulant effect of activated protein C (APC-resistance), and represents the most common hereditary risk factor for venous thrombosis. A comparison of the ability of non-radioactive single-strand conformation polymorphism (SSCP) and of a standard PCR procedure followed by further digestion with MnlI to detect this factor V gene (FVQ 506) transition indicates that these is a good agreement between the two methods. Non-radioactive SSCP analysis therefore represents a rapid and sensitive alternative for the diagnosis of this important point mutation.

DNA Mutational Analysis↗
PubMed1997

Protection of the infant thyroid from radioactive contamination by the administration of stable iodide. An experimental evaluation in chimpanzees.

Protection of the thyroid from radioactive contamination by the administration of stable iodide was investigated in chimpanzees aged 2 to 98 weeks. The uptake of iodide in the thyroid was measured with 123I-. The animals were subjected to a control measurement first, and subsequently the thyroid uptake of 123I- was determined twice; once at the start and once at the end of 11 days of ingestion of 0.5, 1.5 or 5.0 mg of stable iodide per kg body weight per day. The three doses of iodide reduced the control thyroid iodide uptake of 10 to 30% to lower than 1% when ingested 1 h before exposure to the tracer and to 2-4% when ingested 20 h before exposure. In the latter experiments 0.5 mg iodide/kg was less effective than doses of 1.5 mg/kg or higher. The physiological state of the thyroid of control infant chimpanzees does not differ from that of human infants. Incidentally, an increased level of TSH was found during the ingestion of iodide, but with unaltered thyroxine levels. Therefore, it is concluded that a daily dose of 1.5 mg stable iodide/kg body weight and higher offers optimal protection of the thyroid against exposure to radioactive iodine in infants and that, when used during 10 days, it leaves the thyroid unaffected.

Animals↗
PubMed1997

Estimation of radioactive calcium absorption based on expanding Ca-exchangeable space.

Anthropological interest in calcium metabolism is partially connected with the genetic basis of skeletal metabolism that could provide additional optimism for people suffering from osteoporosis. The present investigation is aimed at deal with a of model describing Ca intestinal absorption, suitable for other descriptions currently investigated in anthropology (migration and gene flow). The purpose of this investigation was to establish features of the reflection of the Ca isotopic absorption tests in serum using the concept of an expanding Ca-space and to assess the reliability of the estimation of absorption (ABS) from one serum sample. Double tracer method, using 85Sr as the iv tracer, was used as the referent. The study included 100 subjects (49 females, 51 males) of which 34 were considered healthy. The mean value of ABS was 68 (+/-17.45 SD) % of dose. Serum radioactivity during the 24 hours following oral administration of 47Ca (together with 100 mg elemental Ca), o.s(t), from five blood samples was determined. The relationship between o.s(t) and ABS was found to be connected to an expanding Ca-space, V(t): ABS = o.s(t)V(t) = 26 + 11.8t0.35 o.s(t). After the absorption process was finished, an approximate value of V(t) is (100/S1)(t-x)b. The constants "S1" and "b" describe power function of iv s(t), whereas parameter "x" represents delay of V(t) Ca-space at oral administration in comparison to the iv administration. Statistical models selected on the basis of their low values of the SEE (from 8.71 to 8.90% of dose) include body surface index or body weight index (BW0.425). The CV expressed as (SEE/mean x ABS(Ca/Sr) x 100 were about 13% and the observed greatest difference between the estimated and measured ABS(Ca/Sr) was 20% of dose. The authors believe that models presented permit, to a limited extent, comparison of results obtained by different procedures. The results, according to variability of the sample of subjects, permit judgment on upper limits of error at estimation of absorption from one blood sample radioactivity.

Adult↗
PubMed1977

Estimation of the migration of thoracic duct lymphocytes to non-lymphoid tissues. A comparison of the distribution of radioactivity at intervals following i.v. transfusion of cells labelled with 3H, 14C, 75Se, 99mTc, 125I and 51Cr in the rat.

The distribution of radioisotopes in tissues was measured following i.v. injection of labelled thoracic duct lymphocytes into syngeneic rats. The rate of elution of an isotope from the labelled cells and the subsequent fate of the eluted isotope were shown to be the most important factors limiting the usefulness of such isotopes for measuring cell localization particularly in non-lymphoid tissues. Comparison of labelling procedures using [3H] and [14C]uridine, [3H] and [14C]leucine, [75Se]-L-selenomethionine, [99mTc]sodium pertechnetate and [51Cr]sodium chromate in vitro and [3H]thymidine in vivo showed that 51Cr had the fewest disadvantages in the present context. Using 51Cr-labelled cells, the radioactivity was measured in a wide range of non-lymphoid tissues, and estimates of cell traffic were obtained. In skin, for example, the results indicate a cell flux in the range of 10(4)-10(5) lymphocytes/gm/hr. Evidence is presented which suggests that the early substantial localization of labelled cells in the lung is not an artefact due to sequestration or embolization of traumatized cells but probably reflects a slow intravascular transit time through this capillary bed. The primary lymphoid organs, thymus and bone marrow were shown to include a subpopulation of lymphocytes which belong to the recirculating pool. The thymus always contained a greater concentration of radioactivity at 24 hr than all non-lymphoid tissues except liver and kidney (approx. 0-1% of the recirculating lymphocyte pool) and the bone marrow was capable of temporarily accepting a substantial proportion (approx.25%) of the injected cells.

Animals↗
PubMed1998

CuTira brachytherapy: a new combination of radioactive copper isotopes and the hypoxic cytotoxin, tirapazamine, for targeted tumor therapy.

We previously showed a significant enhancement of tirapazamine-induced cytotoxicity and DNA damage after binding with copper. This result suggests that conjugates of tirapazamine with radioactive copper, i.e., 64Cu and 67Cu, may offer potential for targeted therapy of a wide range of advanced stage tumors including a possible treatment for patients with solitary hepatocellular carcinoma by intrahepatic arterial infusion. Major supporting considerations include: (a) tirapazamine having a high selective toxicity against hypoxic cells; (b) the nature of radioactive decay of these copper isotopes and obtainable high specific activity; and (c) simple procedure for the production of copper-tirapazamine complex.

Brachytherapy↗
PubMed1976

Imaging small pulmonary ischemic lesions after radioactive carbon monoxide inhalation.

A new method is described for imaging small ischemic regions in the lung immediately after a single breath of radioactive carbon monoxide (11CO). A tungsten-collimated scintillation camera is used to visualize the 0.51-MeV annihilation photons due to the 11C. In normal dogs the entire field is cleared of 11CO within 10 sec. However, in dogs with experimentally occluded 2-mm-diam segmental arteries, the ischemic but well-ventilated segment appears as a region of persistent high radioactivity, due most likely to temporary entrapment of 11CO-labeled red blood cells in the ischemic region. This technique also provides a simple noninvasive means for instantly labeling the systemic circulation without left heart catheterization.

Animals↗
PubMed1998

Revised Nuclear Regulatory Commission regulations for release of patients administered radioactive materials: outpatient iodine-131 anti-B1 therapy.

UNLABELLED: The Nuclear Regulatory Commission regulations for the release of patients administered radioactive material have been revised to include dose-based or activity-based criteria. METHODS: The revised 10 CFR 35.75 regulations and the formula that can be used to determine when an individual patient administered radioactivity is releasable are reviewed. The implications of these new regulations on patient release after 131I anti-B1 therapy for the treatment of non-Hodgkin's lymphoma are also discussed. RESULTS: A licensee may now release patients if the total effective dose equivalent to another individual from exposure to a released patient is <500 mrem. Compliance with this dose limit is demonstrated by licensees either by using a default table for activity or dose rate provided in Regulatory Guide 8.39 or by performing a patient-specific dose calculation. Licensees may also demonstrate compliance by basing patient release on the patient-specific measured dose rate at 1 m instead of administered activity. Data on more than 50 patients receiving 131I anti-B1 therapy, an investigational therapy for non-Hodgkin's lymphoma, indicate that all patients would have been releasable under the new regulations. CONCLUSION: The new regulations will permit 131I anti-B1 therapy to be conducted on an outpatient basis.

Ambulatory Care↗
PubMed1976

Induced fat embolism in rabbits by means of radioactively labelled fat. Evaluation of different treatments.

Fat embolism was induced in the rabbit by administering a suspension containing radioactively (triglyceride) labelled homologous fat. Different kinds of treatment were tested: Ringerdex, 2% dextran 70, 2.2% dextran 40 SoluMedrol, and EPL-a phospholipid mixture with detergent properties. It was sound that fat injection gave a macroscopically and histologically verifiable fat embolism with lung edema. 2% dextran 70 significantly increased edema, whereas 2.2% dextran 40 did not. SoluMedrol significantly decreased edema caused by fat injection. Of the triglyceride administered, 99.5% was recovered as such from the lungs. Practically no radioactivity was found in cerebrum and kidneys. Compared with Ringerdex, no other treatment increased elimination of fat from lungs.

Animals↗
PubMed1994

Radioactive contamination of forests in Poland.

Partial results of a large survey of radioactive contamination in Polish forests are presented. All measurements were performed with low-background gamma spectrometers. The measurement method is briefly described. Activities of 137Cs, 134Cs, 125Sb, 106Ru, 144Ce, 154Eu, 155Eu, and 60Co in A0 and A1 layers of forest litter from all over Poland are determined. The geographical distribution of contamination as well as its origin is discussed. Nonuniform composition of the Chernobyl fallout over Poland is confirmed and documented.

Agaricales↗
PubMed2005

Northern conditions influencing the selection of countermeasures after radioactive fallout in Finland.

The paper summarizes an evaluation of practicability of rural countermeasures after radioactive fallout in northern conditions carried out by a Finnish group of experts in the FARMING Network project. Snow and soil frost limit the selection of crops, and the short growing season allows mostly one harvest yearly. Cold climate restricts fruit production to apples and berries. Due to the long indoor feeding period, conserved and stored clean feed is available almost all year round. The use of fertilisers and lime on poor and acidic soils leads to high potassium and calcium intake of cows increasing the incidence of milk fever. The surface soil layer is thin and ploughing deeper than 20 cm is problematic due to stony and compacted soils. It also increases soil acidity and decreases fertility. Cultivation of peatlands limits the selection of plants and increases long-term radiocaesium contamination of crops. Frost and snow delay ploughing and spreading of waste milk on arable land, but removal of snow is a decontamination option. Long distances and high transport costs complicate carrying out the countermeasures. The Finnish stakeholder group considered it vital to be prepared for implementation of practicable measures for the safety of food.

Agriculture↗
PubMed2004

Levels and trends of radioactive contaminants in the Greenland environment.

Levels of radioactive contaminants in various Greenland environments have been assessed during 1999-2001. The source of 137Cs, 90Sr and (239,240)Pu in terrestrial and fresh water environments is mainly global fallout. In addition, the Chernobyl accident gave a small contribution of 137Cs. Reindeer and lamb contain the largest observed 137Cs concentrations in the terrestrial environment--up to 80 Bq kg(-1) fresh weight have been observed in reindeer. Due to special environmental conditions, 137Cs is transferred to landlocked Arctic char with extremely high efficiency in South Greenland leading to concentrations up to 100 Bq kg(-1) fresh weight. In these cases very long ecological half-lives are seen. Concentrations of 99Tc, 137Cs and 90Sr in seawater and in marine biota decrease in the order North-East Greenland and the coastal East Greenland current > South-West Greenland > Central West Greenland and North-West Greenland > Irmiger Sea-Faroe Islands. The general large-scale oceanic circulation combined with European coastal discharges and previous contamination of the Arctic Ocean causes this. As the same tendency is seen for the persistent organic pollutants (POPs) DDT and PCB in marine biota, it is suggested that long-distance oceanic transport by coastal currents is a significant pathway also for POPs in the Greenland marine environment. The peak 99Tc discharge from Sellafield 1994-1995 has only been slightly visible in the present survey year 2000. The concentrations are expected to increase in the future, especially in East Greenland. The Bylot Sound at the Thule Airbase (Pituffik) in North-West Greenland was contaminated with plutonium and enriched uranium in a weapons accident in 1968. Biological activity has mixed accident plutonium efficiently into the new sediments resulting in continued high surface sediment concentrations three decades after the accident. Transfer of plutonium to benthic biota is low--and lower than observed in the Irish Sea. This is supposed to be caused by the physico-chemical form of the accident plutonium. A recent study indicates that 'hot particles' hold considerably more plutonium than previously anticipated and that the Bylot Sound sediments may account for the major part of the un-recovered plutonium after the accident, i.e. approximately 3 kg.

Animals↗