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At least 1,441 records · Page 80Linked to original sources
PubMed1995

A non-radioactive DNA sequencing method using biotinylated dideoxynucleoside triphosphates and delta Tth DNA polymerase.

We synthesized a set of four biotinylated dideoxynucleoside triphosphates (biotin-9-ddNTPs) and optimized the reaction conditions for non-radioactive cycle sequencing using modified Tth DNA polymerase (delta Tth) and a chemiluminescent detection system. The resulting sequencing ladders showed lower background compared to those with the conventional non-radioactive sequencing method which uses 5'-biotinylated primers, especially when PCR products were analysed. With our method, DNA sequences can be determined at any primer positions without preparing 5'-biotinylated primers for dideoxy chain-termination.

Biotin↗
PubMed1980

Excretion and tissue distribution of radioactive lysinoalanine, N epsilon-DL-(2-amino-2-carboxyethyl)-U-14C-L-lysine (LAL) in Sprague-Dawley rats.

Rats were fed either a control soybean protein diet or a diet containing 3,000 ppm soybean protein-bound lysinoalanine (LAL) for 4 or 6 weeks, at which time all rats were dosed by stomach tube with 14C-LAL labeled in the lysine moiety. Urinary and fecal excretion and tissue distribution were followed in one experiment at 6, 12, 18, 24, 48 and 72 hours. Excretion in urine, feces and expired air was followed in the other metabolic experiment at 2-hour intervals for 48 hours, and at 24-hour intervals for the next 7 days. Tissue samples were counted and LAL determination was made by amino acid analysis in both experiments. The group of rats fed LAL excreted slightly more LAL than the group fed the control diet. Very little LAL remained in the rat tissues after either experiment, and the largest remaining quantity of radioactivity was found as lysine. Quantitation of 14C-lysine in the original material and in the material from rat organs showed that the rat has some capacity for converting LAL to lysine. Less than 0.5% of the original 14C remained in any organ examined 9 days after dosing in the either control or LAL-fed rats. Autoradiographs of the kidneys 24 hours after dosing showed that the radioactive material had accumulated in the proximal convoluted tubules of the corticomedullary junction.

Animals↗
PubMed1984

Triacylglycerol secretion in rats: validation of a tracer method employing radioactive glycerol.

A two-compartment model was developed to analyze the temporal changes in plasma triacylglycerol (TG)-specific radioactivity after injection of [2-3H]glycerol into rats. The analysis, which yielded fractional rate constants of TG secretion, was tested in rats fed diets either adequate or deficient in essential fatty acids (EFA) and containing either glucose, fructose or sucrose as the dietary carbohydrate. The method of analysis appeared valid, first, because of a close agreement between experimental and computer-fitted TG-specific radioactivity curves, and second, because the fractional rate constants obtained were quite similar to fractional rate constants determined previously by the Triton WR-1339 technique in rats maintained on identical diets. The results show that EFA deficiency increased the fractional rate constant of TG secretion 1.7-, 1.8- and 3.3-fold and the rate of TG secretion 1.8-, 1.6- and 1.4-fold when the dietary carbohydrate was glucose, sucrose and fructose, respectively, in comparison with control rats fed diets supplying these same carbohydrates but adequate in EFA. In the latter groups, the rates of plasma TG secretion were in the range of 0.14-0.17 mg/min per 100 g body weight, and the rate of secretion in the fructose-fed rats was only 20% higher than in the glucose-fed rats.

Animals↗
PubMed1999

Oral administration of (14)C labeled gelatin hydrolysate leads to an accumulation of radioactivity in cartilage of mice (C57/BL).

Several investigations showed a positive influence of orally administered gelatin on degenerative diseases of the musculo-skeletal system. Both the therapeutic mechanism and the absorption dynamics, however, remain unclear. Therefore, this study investigated the time course of gelatin hydrolysate absorption and its subsequent distribution in various tissues in mice (C57/BL). Absorption of (14)C labeled gelatin hydrolysate was compared to control mice administered (14)C labeled proline following intragastric application. Plasma and tissue radioactivity was measured over 192 h. Additional "gut sac" experiments were conducted to quantify the MW distribution of the absorbed gelatin using SDS-electrophoresis and HPLC. Ninety-five percent of enterally applied gelatin hydrolysate was absorbed within the first 12 h. The distribution of the labeled gelatin in the various tissues was similar to that of labeled proline with the exception of cartilage, where a pronounced and long-lasting accumulation of gelatin hydrolysate was observed. In cartilage, measured radioactivity was more than twice as high following gelatin administration compared to the control group. The absorption of gelatin hydrolysate in its high molecular form, with peptides of 2.5-15kD, was detected following intestinal passage. These results demonstrate intestinal absorption and cartilage tissue accumulation of gelatin hydrolysate and suggest a potential mechanism for previously observed clinical benefits of orally administered gelatin.

Administration, Oral↗
PubMed1988

Non-radioactive automated sequencing of oligonucleotides by chemical degradation.

A non-radioactive sequencing of fluorescently labelled oligonucleotides by solid-phase chemical degradation is described. Although non-radioactive methods have been reported for the dideoxy chain termination technique, such a method has not yet been developed for the chemical degradation sequencing of DNA fragments. A 21-mer fluorescein labelled M13 sequencing primer was sequenced in an on-line automated system in about 30 minutes. The fluorescent dye and its bond to the oligonucleotide were stable during the chemical reactions used for the base specific degradations. As the sequence is determined on-line during electrophoresis, reloading and running 10 fragments simultaneously allows us to use one gel for sequencing of about 50 different oligonucleotides.

Automation↗
PubMed1990

The preparation of polyamide-oligonucleotide probes containing multiple non-radioactive labels.

Oligonucleotide probes containing multiple non-radioactive labels have been prepared by utilising and extending the methods used to prepare polyamide-oligonucleotide conjugates. The probes were prepared by incorporating suitable amino acid residues, such as lysines, in the polyamide, which were then used as sites for the attachment of the non-radioactive labels. The procedures developed give control over the distance of the label from the oligonucleotide, and also the inter-label distance. The labels can be conveniently introduced while the substrate is still on the solid support. Even though fluorescent oligonucleotide probes prepared in this way carrying multiple carboxyfluorescein labels gave low levels of fluorescence due to quenching, the probes containing ten biotin labels gave a detection sensitivity of approximately 5 attomole (3 million molecules).

Animals↗
PubMed2003

Development and assessment of a new radioactive decay database used for dosimetry calculation.

The present paper discusses the technical issues and a scheme for their resolution before undertaking the development of a new radioactive decay database to succeed ICRP38. The scheme consists of the following procedures. (1) The consistency of nuclear structure data files used as input to the computer code EDISTR is established by referring to the latest nuclear parameters and by comparing the computed energies of emitted radiations with total decay energy. (2) A method for calculating detailed spectra of X rays and Auger electrons is incorported into EDISTR to enhance the treatment of atomic relaxation processes initiated by electron vacancies from internal conversion and electron capture. (3) Quality assurance of the compiled data is undertaken by comparisons with experimental data and other decay databases prepared from different computer codes and libraries. JAERI and ORNL are cooperating to implement the scheme in order to assemble a comprehensive radioactive decay database including over 1000 nuclides.

Database Management Systems↗
PubMed2001

Experimental and measurement issues in natural radioactivity.

The paper deals with some open experimental problems in the field of natural radioactivity. Its aim is to stimulate discussion on the type of research efforts needed in the field and to be planned for the future. The review, which makes no claims to completeness. analyses some issues in gamma spectrometry of natural radionuclides, and the measurement of natural radioactivity in non-nuclear industries and of 222Rn and 220Rn concentration in air.

Background Radiation↗
PubMed2005

Evaluation of induced radioactivity in structural material of Toshiba Training Reactor 'TTR1'.

A decommissioning programme for the Toshiba Training Reactor (TTR1), a swimming pool type reactor used for reactor physics experiments and material irradiation, was started in August 2001. As a part of the programme, induced radioactivity in structural material was evaluated using neutron flux data obtained with the three-dimensional Sn code TORT. Induced activity was calculated with the isotope generation code ORIGEN-79 using activation cross section data created from multi-group library based on JENDL-3. The obtained results for radioactivities such as 60Co, 65Zn, 54Mn and 152Eu were compared with measured ones, and the present calculational method was confirmed to have enough accuracy.

Computer Simulation↗
PubMed2005

Radiation issues in a radioactive ion decay ring.

In a beta-beam facility, a pure beam of electron neutrinos, or their antiparticles, are produced by the decay of fully stripped radioactive ions (6He and 18Ne) circulating in a storage ring. Since the beam is not extracted from the ring, all the particles will eventually be lost somewhere in the machine and thus activate the accelerator components and the surrounding concrete and rock. In particular, as nuclei change their charge in beta-decay, a large part of the particles will be lost in the arcs of the decay ring and mainly irradiate the magnets. The density of inelastic interactions of hadrons in the magnets, concrete and rock and the track-length distribution of secondary hadrons were calculated by means of the FLUKA Monte Carlo code. These values were used to estimate the induced radioactivity in the facility, the dose rates expected in the decay ring and the consequences for the environment.

Beta Particles↗
PubMed2006

Workplace characterisation in case of rail transport of radioactive materials.

IRSN has been asked by SNCF (French Railways) to carry out measurements in order to establish the values of ambient dose equivalents H*(10) in the vicinity of shipments of radioactive materials to assess the external exposure to ionising radiation to which employees may be subjected during the carriage of radioactive goods. Detailed dosimetric characterisations of the wagons have been made and the external exposure at different stages of the work that is done by the employees have been measured in terms of H*(10). For the study presented in this paper, and corresponding to a used fuel shipment composed of UO2 and UO2-PuO2, it has been observed that the photon and neutron doses are very similar. In addition, the order of magnitude of the total dose integrated by an employee who would carry out 100 times the series of essential operational tasks, has been found to be approximately 250 microSv. This value is compared with those observed for other previously investigated shipments involving the exposure to photon fields only.

Body Burden↗
PubMed2006

Evaluation of the radioactivity of the pre-dominant gamma emitters in components used at high-energy proton accelerator facilities.

At a high-energy, high-intensity proton accelerator facility, the accelerator components inside the beam-line tunnel and the concrete wall of the tunnel are activated due to beam loss during operation. During maintenance work inside the tunnel, radiation emitted from these activated materials can cause exposure to radiation workers. In this study, the relation between the surface dose rate of activated materials and the induced radioactivity was considered, and an evaluation of the major radioactivity using the surface dose rate was made. It has been revealed that (22)Na in Al samples and (54)Mn in Fe samples, (60)Co and (54)Mn in Fe samples, and (60)Co in Fe and Cu samples are principal residual radionuclides after a few hundred days of cooling about a few years of cooling and approximately 10 y of cooling, respectively.

Construction Materials↗
PubMed2007

Assessment of natural radioactivity and the associated hazards in Iranian cement.

This paper presents the finding of a study undertaken to determine natural radioactivity and associated hazards in local types of cement in Iran. A total of 42 samples were collected from various manufacturers and suppliers and analysed using a shielded HPGe gamma-ray spectrometer. The specific activities of 232Th, 226Ra and 40K were measured in samples and results ranged from minimum values of 8, 16, 101 Bq kg(-1) to maximum values of 17, 43 and 141 Bq kg(-1), respectively. On the basis of activity concentration index (I), it could be shown that, the radioactivity of local cement samples was not greater than the established standard values in other countries.

Background Radiation↗
PubMed1983

Measure of blood flow by the multiple radioactive microsphere technique in radiated gastrointestinal tissue.

In this study, two different radioactive microspheres were used to measure blood flow of an irradiated segment of small intestine in four dogs before, and 12 days after, irradiation with 2000 rad. The technique and implications are discussed. Using multiple radioactive microspheres, the study demonstrated an increased blood flow in irradiated tissues twelve days after a single dose of 2000 rad. There was also an increase in blood flow to adjoining nonradiated segments of intestine in the same animal. These observations may be of significance in clinical applications of radiation therapy and surgery. A major surgical concern is the impaired healing of irradiated tissue in the immediate postradiation period. The mechanism of this has generally implicated decreases in the perfusion of irradiated tissue. No decrease in blood flow was shown in this study, suggesting that other mechanisms, e.g., stem cell depletion, should be considered. Further studies of this type are recommended to increase understanding of the blood flow in irradiated tissue.

Animals↗
PubMed1990

Detection of chromogranins A and B in endocrine tissues with radioactive and biotinylated oligonucleotide probes.

We analyzed the distribution of chromogranins A and B in normal and neoplastic endocrine tissues with secretory granules using 35S-labeled and biotin-labeled oligonucleotide probes by in situ hybridization (ISH). Both radioactive and nonradioactive probes detected messenger RNAs (mRNAs) in frozen and paraffin tissue sections. Endocrine tissues with variable immunoreactivities for chromogranin A protein, such as small-cell lung carcinomas, neuroblastomas, insulinomas, and parathyroid adenomas, expressed the mRNA for chromogranins A and B in most cells. Some technical problems with the biotinylated probes included nonspecific nuclear staining and endogenous alkaline phosphatase, which was not completely abolished by levamisole pretreatment. A differential distribution of chromogranins A and B was seen in pituitary prolactinomas, which expressed abundant chromogranin B but not chromogranin A mRNAs, and in parathyroid adenomas, which expressed abundant chromogranin A but only small amounts of chromogranin B mRNAs. These results indicate that ISH can be used to detect chromogranins A and B in endocrine tissues with radioactive and biotinylated oligonucleotide probes and that the mRNAs for chromogranin A and B are demonstrable in some tumors even when the chromogranin proteins cannot be detected by immunohistochemistry.

Biotin↗
PubMed2000

Recommendations for handling radioactive specimens obtained by sentinel lymphadenectomy. Surgical Pathology Committee of the College of American Pathologists, and the Association of Directors of Anatomic and Surgical Pathology.

Sentinel lymph node biopsy has been shown to be an accurate predictor of axillary nodal status in invasive breast cancer and is a useful alternative to axillary dissection for some patients. Because radioactive materials are often used to identify the sentinel lymph node, concerns have been raised regarding the safe handling of tissue specimens obtained by this technique. The Surgical Pathology Committee of the College of American Pathologists and the Association of Directors of Anatomic and Surgical Pathology have developed recommendations for the safe handling of radioactive specimens obtained by sentinel lymphadenectomy.

Axilla↗
PubMed1986

Diffuse thoracoabdominal radioactivity seen in bone imaging.

Diffusely increased radioactivity in the thoracoabdominal region (lower thorax and/or upper abdomen) occasionally has been observed when performing Tc-99m phosphonate bone studies. To assess the significance of activity in this finding, 1100 bone scintigrams were reviewed and the clinical data and other diagnostic imaging procedures were evaluated in these cases. With the exclusion of Tc-99m sulfur colloid liver-spleen scans 18 patients were found to have mild but diffuse increased radioactivity in the thoracoabdominal region either on the right or left. Clinical findings in these cases with abnormal uptakes were pleural effusions (six cases), hepatic colonic metastases (six cases), splenic metastases from bronchogenic carcinoma (one case), abdominal and peritoneal colonic metastases (one case), a massive metastatic squamous cell carcinoma (from lung) in the right lower chest (one case), and defective radiopharmaceuticals (three cases). Since the defective radiopharmaceuticals contained 5% of hydrolyzed reduced Tc-99m colloid by thin-layer chromatography, each of three patients received approximately 740 mu Ci of Tc-99m sulfur colloid. Factors to be considered in the interpretation of diffuse thoraco-abdominal activity from a bone agent should include splenic or hepatic metastases, a Tc-99m sulfur colloid splenic or hepatic metastases, a Tc-99m sulfur colloid study within the previous 24 hours, pleural effusion, faulty radiopharmaceuticals, and abdominal and peritoneal colonic metastases.

Abdomen↗
PubMed1986

The radioactivity of spas on the Greek island Ikaria and influencing factors.

The aim of this research is the qualitative and quantitative determination by gamma-spectroscopy analysis of all the natural radioisotopes which exist in the waters of the municipal thermometallic radioactive springs (spas) of the Greek island Ikaria. An explanation is suggested for the different concentrations of natural radioisotopes in these spa waters in connection with physical factors (geological composition, temperature of the spas, etc.). In addition to the aforementioned, we also seek to compare radioactivity values of different spas during the same season as well as of an individual spa at different seasons of the year.

Balneology↗