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PubMed1977

Relation between cholic acid synthesis rate and faecal radioisotope excretion following oral administration of 14C-cholic acid.

Bile acid kinetics were evaluated after oral administration of 14C-labelled cholic acid in ten normal subjects and two patients with severe bile acid malabsorption. The faecal 14C excretion was measured during the turnover study. Cholic acid synthesis rate was significantly correlated to 14C output in stools. The faecal radioisotope excretion is recommended for detection and semi-quantitation of bile acid malabsorption.

Administration, Oral↗
PubMed1975

A radioisotopic method to measure delayed type hypersensitivity in the mouse. I. Studies in sensitized and normal mice.

Delayed type hypersensitivity (DTH) lesions have been difficult to evaluate objectively in the mouse because they are usually assessed in terms of an increase in footpad swelling or ear thickness. We have developed a radioisotopic method which not only reduces the observer's error but also gives an objective measurement of the cellular activity in the lesions. In brief, 10 mul of the test antigen is injected intradermally into the left pinna and either nothing or the same volume of a control solution into the right. 10 h later, a 2-muCi pulse of 5-iodo-2'deoxyuridine-125I is given intravenously, the ears cut off at the hairline 16 h later and the radioactivity counted in a gamma spectrometer. The following was obtained as evidence that the increased radioactivity of the left pinna over the right was a measure of the extent of a DTH response: (1) the ear reaction was delayed in mice without serum antibodies becoming maximum at 24 h; (2) there was a mononuclear cell infiltration in the left pinna and autoradiographs revealed radioactive label bound to these cells; (3) athymic mice could not develop a 24-hour ear reaction, and (4) antigens known not to activate T cells did not elicit the ear response. Cell transfer studies will be described in a subsequent paper. Different sensitization regimes were required with different antigens in order to obtain the highest levels of DTH as tested by the ear response, and the maximal ear reaction occurred at different days. The ear reaction showed the specificity expected of a DTH response.

Animals↗
PubMed1975

A radioisotopic method to measure delayed type hypersensitivity in the mouse. II. Cell transfer studies.

Sensitized lymphoid cells could transfer to normal non-sensitized (naive) mice by 24-48 h after antigen challenge in the ear, the capacity to incorporate, at the site of antigen deposition, 5-iodo-2'deoxyuridine-125I in amounts significantly above those obtained in control mice. This was associated with a mononuclear cell infiltration in the pinna. In contrast to lymphoid cells, serum antibodies were unable to transfer a 24- or 48 hour ear reaction. The cells responsible were T lymphocytes as demonstrated by successful transfer following enrichment for T lymphocytes, and abrogation of transfer following treatment with anti-theta serum and complement. Transfer was achieved whether the naive recipients were normal, T-cell deprived, pretreated with cyclophosphamide, or lightly irradiated but not when they were heavily irradiated. Adoptive transfer of the 24-hour ear response was demonstrated with three different antigenic systems. The time-response curves were different with each system although peak reactions were obtained 5 days after sensitization of the donors in all cases. The specificity patterns of the 24-hour ear reaction on transfer were similar to those obtained in the sensitized donors. The results of these studies indicate that the radioisotopic ear method can, under defined conditions, demonstrate the existence of a state of delayed type hypersensitivity in the donors.

Animals↗
PubMed1980

Kidney and bladder pulsating activities during radioisotope renogram by computer data analysis.

This is a report of a new method in which the mathematical study of radioactivity changes in the bladder and kidney shows evidence of pulsating and vibratory activities. This study was done during radioisotope renogram with 99mTc DTPA. Spectral analysis of the recorded activities, taken 50 frames/sec and 1 frame every 10 sec by a scintillation camera connected to a computer, shows evidence of pulsating and vibratory activities of the kidney and the bladder. Slow pulsations with a period from 1/2 to 2 1/2 min were identified. Infrasonoric vibrations, from 2 to 25 Hz were found in the kidney, in a full bladder and during micturition.

Adult↗
PubMed1984

A radioisotopic assay for delta 1-pyrroline-5-carboxylate synthase activity.

A radioisotopic assay is described for measuring the activity of delta 1-pyrroline-5-carboxylate synthase, the enzyme that catalyzes the formation of delta 1-pyrroline-5-carboxylic acid from glutamic acid. Pyrroline-5-carboxylic acid is a common intermediate in the pathways through which glutamic acid, proline, and ornithine are interconverted. To determine pyrroline-5-carboxylate synthase activity, cell homogenates are incubated with [14C]-glutamic acid, the products of the reaction are converted quantitatively to proline by sodium borohydride, and proline is isolated by cation-exchange column chromatography. Cofactor requirements have been defined, and the activity of pyrroline-5-carboxylate synthase in several different cultured fibroblast lines is reported.

Animals↗
PubMed1983

Clinical significance of the radioisotope test using I-131 labelled serum albumin for evaluating the peripheral circulation in the foot during a period of reactive hyperemia.

The radioisotope test using I-131 labelled serum albumin, performed during a period of reactive hyperemia, provides quantitative data which express the rate at which radioactive blood flowing from the leg replaces the non-radioactive blood present in the foot. It has been applied in normal subjects and in patients with arterial occlusions in the lower limbs. High washout rates, i.e. small M/2 index values, were found in the former, whereas low washout rates with higher M/2 indices were observed in the latter. Surprisingly, patients with a very low washout rate could be without subjective symptoms. The usefulness of the test in clinical practice is explained.

Adult↗
PubMed2002

Increased concentrations of radioisotopically-labeled complementary ribonucleic acid probe, dextran sulfate, and dithiothreitol in the hybridization buffer can improve results of in situ hybridization histochemistry.

The goal of the present studies was to optimize mRNA detection with radioisotopic in situ hybridization histochemistry (ISHH). Test experiments performed on sections of rat brain tissue used computer-assisted image analysis to compare autoradiographic signals resulting when varying concentrations of (35)S-labeled cRNA probes, dextran sulfate (DS), and dithiothreitol (DTT) were used for ISHH. We found that greatly enhanced corrected signal density (total density of signal area minus background density) was obtained using concentrations of probe and/or DS that were several-fold higher than those widely recommended in published ISHH procedures (probe concentration >4 x 10(4) cpm/microl; DS concentration >10%). Extended hybridization reaction (>16 hr) also significantly augmented the corrected signal density. Finally, nonspecific probe binding was greatly reduced and corrected signal density enhanced by including 750-1000 mM, rather than the widely used 10-200 mM DTT, in the hybridization buffer. These observations indicate that the low efficiency of hybridization and the formation of high background may largely compromise the sensitivity of routine ISHH procedures. We suggest that the new method using increased concentrations of (35)S-labeled cRNA probe, DS, and DTT will be especially important for the cellular localization of rare mRNA species.

Animals↗
PubMed2004

Experimental system to displace radioisotopes from upper to deeper soil layers: chemical research.

BACKGROUND: Radioisotopes are introduced into the environment following nuclear power plant accidents or nuclear weapons tests. The immobility of these radioactive elements in uppermost soil layers represents a problem for human health, since they can easily be incorporated in the food chain. Preventing their assimilation by plants may be a first step towards the total recovery of contaminated areas. METHODS: The possibility of displacing radionuclides from the most superficial soil layers and their subsequent stabilisation at lower levels were investigated in laboratory trials. An experimental system reproducing the environmental conditions of contaminated areas was designed in plastic columns. A radiopolluted soil sample was treated with solutions containing ions normally used in fertilisation (NO3-, NH4+, PO4--- and K+). RESULTS: Contaminated soils treated with an acid solution of ions NO3-, PO4--- and K+, undergo a reduction of radioactivity up to 35%, after a series of washes which simulate one year's rainfall. The capacity of the deepest soil layers to immobilize the radionuclides percolated from the superficial layers was also confirmed. CONCLUSION: The migration of radionuclides towards deeper soil layers, following chemical treatments, and their subsequent stabilization reduces bioavailability in the uppermost soil horizon, preventing at the same time their transfer into the water-bearing stratum.

Accidents↗
PubMed1975

Gall-bladder emptying measured by a radioisotopic method.

A method of oral radioisotope cholecystography is described using 131I sodium ipodate. Gall-bladder emptying was measured by this method and radiographically: (a) in a model, (b) in 34 patients having oral cholecystography. There was a good correlation between the two methods of measuring volume changes, both in vitro and in vivo. The isotope cholecystogram has the advantage of a lower radiation hazard, and is the only satisfactory method of studying the onset, rate and duration of gall-bladder emptying. These may be easily measurable markers of disorders of the upper small bowel.

Cholecystography↗
PubMed1976

The measurement of the performance of the display system of radioisotope imaging device: the multi-element band display.

An assessment has been made of the performance of the type of display system in which each display signal intensity, i.e. grey shade or colour, represents a range of count densities or counting rates. In the particular commercially available system used in this investigation eight different grey shades are used to display the image, a range of count densities beingallocated to each grey shade. It is shown experimentally that changes in the distribution of radioisotope can fail to be detected solely due to the manner in which the display is used, viz. The way in which the count density is allocated to the available grey shades. Also, it is shown experimentally that the best display performance can be achieved by using one in which the range of count densities represented by each grey shade is less than three standard deviations of the mean background [corrected] count density.

Background Radiation↗
PubMed2003

Intraductal injection of the breast: a potential pitfall of radioisotope occult lesion localization.

The use of radioisotope for the localization of occult breast lesions (ROLL) has been advocated in preference to wire guided excision as it allows reduced excision volume and better lesion centering. However, as this technique is new, potential complications are unknown. In 2 out of 38 ROLL procedures performed at our institution, intraductal injection of isotope has occurred. This was diagnosed on check mammography as non-ionic iodinated contrast was mixed with the isotope. In one of these cases conversion to wire localization was required.

Breast Diseases↗
PubMedDate not supplied

Antimalarial drug susceptibility testing of Plasmodium falciparum in Brazil using a radioisotope method.

From March 1996 to August 1997, a study was carried out in a malaria endemic area of the Brazilian Amazon region. In vivo sensitivity evaluation to antimalarial drugs was performed in 129 patients. Blood samples (0.5 ml) were drawn from each patient and cryopreserved to proceed to in vitro studies. In vitro sensitivity evaluation performed using a radioisotope method was carried out with the cryopreserved samples from September to December 1997. Thirty-one samples were tested for chloroquine, mefloquine, halofantrine, quinine, arteether and atovaquone. Resistance was evidenced in 96.6% (29/30) of the samples tested for chloroquine, 3. 3% (1/30) for quinine, none (0/30) for mefloquine and none for halofantrine (0/30). Overall low sensitivity was evidenced in 10% of the samples tested for quinine, 22.5% tested for halofantrine and in 20% tested for mefloquine. Means of IC 50 values were 132.2 (SD: 46. 5) ng/ml for chloroquine, 130.6 (SD: 49.6) ng/ml for quinine, 3.4 (SD: 1.3) ng/ml for mefloquine, 0.7 (SD: 0.3) ng/ml for halofantrine, 1 (SD: 0.6) ng/ml for arteether and 0.4 (SD: 0.2) ng/ml for atovaquone. Means of chloroquine IC 50 of the tested samples were comparable to that of the chloroquine-resistant strain W2 (137.57 ng/ml) and nearly nine times higher than that of the chloroquine-sensitive strain D6 (15.09 ng/ml). Means of quinine IC 50 of the tested samples were 1.7 times higher than that of the low sensitivity strain W2 (74.84 ng/ml) and nearly five times higher than that of the quinine-sensitive strain D6 (27.53 ng/ml). These results disclose in vitro high resistance levels to chloroquine, low sensitivity to quinine and evidence of decreasing sensitivity to mefloquine and halofantrine in the area under evaluation.

Animals↗
PubMed1981

Relationship between the radioisotopic footpad assay and other immunological assays in tumor bearing rats.

KMT-17, a fibrosarcoma induced by 3-methylcholanthrene in a WKA rat, is a sensitive tumor to various kinds of immunological assays and is a suitable model tumor for the study of the immune status in tumor bearing hosts. The antitumor immune response of KMT-17 bearing rats was studied by a radioisotopic footpad assay (FPA) in comparison with other in vivo and in vitro assays. Delayed hypersensitivity to tumor antigens measured by the FPA was observed from the 8th day after transplantation of KMT-17 cells, reached a peak on the 12-15th day, and then declined in the late stage on the 17th day. The kinetics of the FPA correlated well with those of an in vivo Winn assay and of an in vitro lymphocyte cytotoxicity assay (51Cr-release assay). The appearance of an antitumor antibody detected by a complement dependent cytotoxicity test also correlated well with the kinetics of the FPA. A growth inhibition assay (GIA) for non-specific cell-mediated immunity also showed similar kinetics to that of the FPA. The delayed hypersensitivity footpad reaction to tumor cell extracts measured by this FPA was tumor-specific. These results suggest that the FPA is a simple and reliable in vivo assay for evaluating antitumor immunity in tumor bearing host.

Animals↗
PubMed1981

A new adrenal computer imaging technique using dual-radioisotopes.

Computer processed adrenal imaging using dual-radioisotopes, 6 beta-iodomethyl-19-nor-cholest-5(10)-en-3 beta-ol-131I and 99mTc-phytate was performed in 12 patients with primary aldosteronism and 4 with Cushing's syndrome due to adrenocortical tumor. Adreno-photoscanning and hepato-photoscanning were performed in the same position 2-4 days following intravenous administration of radiocholesterol. The scintigraphic information was stored on cassettes and scan subtraction and a digital-computer method for data smoothing were performed on an oscilloscope. The tumor site could be determined in all cases until day 4 by this computer processed image.

Adosterol↗
PubMedDate not supplied

Transfer of radioisotope from CSF to nasal secretion.

The physiological range of radioisotope (RI) transferred from the CSF to the nasal secretions was observed in 17 subjects without CSF rhinorrhea. A combination of RI cisternography and insertion of cotton pledgets in the nose was used in order to detect the RI transfer in the nasal secretion. The RI ratio was calculated, and those of the 17 subjects were less than 0.3. This is likely to be the normal physiological range of RI transfer.

Adult↗
PubMed1990

Conditions for maximizing and inhibiting synthesis of glutathione in cultured rat lenses: an application of HPLC with radioisotope detection.

This investigation was concerned with factors which would maximize and inhibit L-cyst(e)ine uptake and glutathione synthesis of rat lenses cultured for 24 hours in a medium containing [35S]-L-cystine. The lenticular protein-free extract was separated and quantified by use of HPLC equipment which included an in-line radioisotope detector coupled with extensive post-run computer analysis. Six thiols were assessed for their ability to increase the uptake of L-cyst(e)ine and its utilization for glutathione synthesis. The most successful was 2-mercaptoethanol, which increased the L-cyst(e)ine uptake 3.6-fold and glutathione synthesis 2.9-fold. This work demonstrated that the rate of glutathione synthesis was directly proportional to the rate of uptake of L-cyst(e)ine. An inhibitor of glutathione synthesis, buthionine sulfoximine, in a concentration range of 0.11-3 mM, decreased uptake of the [35S]-label by one-third. The 3.0 mM concentration inhibited glutathione synthesis 98.7% and decreased glutathione 51% in 24 hours. The data indicate that half the glutathione disappeared in 23 hours in these cultured rat lenses. Because determination of this value did not depend upon the variable rate of cysteine transport, the value may approximate the in vivo value.

Animals↗
PubMed1976

[Particle size determination by radioisotope x-ray absorptiometry with sedimentation method].

The possibility of radioisotope X-ray absorptiometry to determine the particle size of powder in conjunction with sedimentation was investigated. The experimental accuracy was primarily determined by Cow and X-ray intensity. where Co'=weight concentration of the particle in the suspension w'=(micron/rho)l/(mu/rho)s-rhol/rhos rho; density micron/rho; mass absorption coefficient, suffix l and s indicate dispersion and particle, respectively. The radiosiotopes, Fe-55, Pu-238 and Cd-109 have high w-values over the wide range of the atomic number. However, a source of high micron value such as Fe-55 is not suitable because the optimal X-ray transmission length, Lopt is decided by the expression, micronlLopt approximately 2/(1+C'ow') by using Cd-109 AgKX-ray source, the weight size distribution of particles from the heavy elements such as PbO2 to light elements such as Al2O3 or flyash was determined.

Aluminum↗