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PubMed1960

Gastro-intestinal blood loss measured by radioactive chromium.

A new technique is described for the measurement of blood loss in the faeces of patients labelled with radioactive chromium ((51)Cr). The method is simple and is probably more accurate at low levels of faecal radioactivity than those previously described. The method will measure as little as 0.02muC of (51)Cr in whole blood in a 24-hour stool. The apparent average daily blood loss in a series of 10 normal people averaged 0.6 ml., with a range of 0.3 to 1.3 ml. Estimations of plasma and salivary radioactivity have been made in an attempt to assess the importance of contamination from eluted (51)Cr. Minor radioactivity in plasma but none in saliva was recorded. Stool contamination from such sources is thought to be insignificant. No significant correlation existed between chemical occult blood tests and isotope measurements, where there was less than 10 ml. of whole blood in a 24-hour stool.

Chromium↗

PubMed1967

Vitamin B12 absorption studies: effect of parenteral non-radioactive B12 on serum level of 57CO vitamin B12.

The intestinal absorption of (57)Co vitamin B(12) has been measured by counting the radioactivity in the serum, and the effect of the parenteral administration of 1 mg. non-radioactive vitamin B(12) two hours after the oral dose has been studied. When parenteral vitamin B(12) was not given, the mean radioactivity in the serum was lower in both patients with pernicious anaemia and in control subjects, and the results in the patients with pernicious anaemia were more definitive. There was no significant difference between the results obtained with an Ekco scaler and those with an I.D.L. scaler. This is the simplest and most convenient method of measuring vitamin B(12) absorption. It is suggested that the test be standardized by giving 0.5 mug. (57)Co vitamin B(12) with a maximal histamine stimulation of intrinsic factor secretion, but without a parenteral dose of non-radioactive vitamin B(12). The results are expressed most usefully as a percentage of the administered dose per litre of serum or plasma.

Anemia, Pernicious↗

PubMed1977

Radioactive conversion products of intramuscularly injected [4-14C]formononetin including sulfates in the urine of hens.

The phytoestrogen formononetin was injected intramuscularly as [4-14C]formononetin into two adult hens. Radioactive materials in the urine for the succeeding 14 days (hen 1) or 16 days (hen 2) were fractionated on DEAE-Sephadex-25 columns by elution with a gradient of NaCl; the four major fractions thus separated were examined by solvent partition, thin-layer chromatography, and enzymic cleavage. The following seven radioactive components were identified in the urine, the average proportions of each being given in terms of percentage of total 14C recovered from the urine: [14C]formononetin (4.3%); [14C]diaidzein (11.4%); [14C]equol (6.8%); [14C]daidzein monosulfate (30.4%); [14C]equol monosulfate (5.8%); [14C]diadzein disulfate (19.8%); and [14C]equol disulfate (6.5%). Small proportions of sulfates of unidentified radioactive phenols were present. Tests for presence of glucosiduronates of 14C-labelled material gave negative results. Radioactive formononetin sulfate was not detected in the urine of either hen.

Animals↗

PubMed1977

Selective enzymatic radioactive and spin labelling of phospholipids in biological membranes: application to study of temperature-induced changes of microsomal phosphatidylinositols and mitochondrial polyglycerophosphatides.

A new method for the covalent radioactive and spin labelling of lipids within isolated biological membranes has been described in detail and applied to studies of temperature-induced changes of microsomal and mitochondrial membranes. The method is based on the enzymatic use of radioactive substrates carrying covalently bound doxyl derivatives of stearic acid in the biosynthesis of phospholipids in isolated membranes. Radioactive-and spin-labelled lipids bound to the microsomal and mitochondrial membranes were then used as internal probes in monitoring temperature-induced changes of these membranes. Since the analysis of isolated radioactive-and spin-labelled lipids revealed the exact composition of membrane-bound labelled lipids, specific temperature-induced changes were correlated with specific lipids of examined membranes. Phosphatidylinositol of microsomal membranes and polyglycerophosphatides (phosphatidyl-glycerol and cardiolipin) of mitochondrial and inner mitochondrial membranes were found to be involved in the apparent formation of lipid clusters at around 20-30 degrees C. Cardiolipin was found to be involved in the fluidization of inner mitochondrial membranes. These findings are discussed in view of the present state of knowledge of the organization of lipids in biological membranes.

Animals↗

PubMed1976

The relationship between radiographic findings and asymmetrical radioactivity in the shoulder.

A prospective study was performed to compare asymmetrical radioactivity in the shoulder on 99mTc bone scans with the conventional radiographic findings of 100 right-handed and 8 left-handed patients. Of the 100 right-handed patients, 30 had increased radioactivity in the right shoulder; 5 showed increased radioactivity on the left. Clinical history, shoulder physical examination, and site of injection did not influence the frequency of asymmetrical radioactivity; only dominant handedness correlated with this finding.

Adolescent↗

PubMed2003

Endovascular treatment of intracranial aneurysms with radioactive coils: initial clinical experience.

BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms is safe and effective but is associated with angiographic recurrences. Beta radiation prevents recanalization after coil embolization in experimental models. We wanted to assess the feasibility of using radioactive coil embolization to improve long-term results of endovascular treatment. METHODS: Platinum coils were ion-implanted with 0.13 to 0.26 microCi/cm of 32P. Forty-one patients aged 34 to 84 years with 44 aneurysms with a high propensity for recurrences were included. Radioactive coils were introduced into aneurysms to reach a target volumetric activity of 0.018 microCi/mm3. Nonradioactive coils were also used to ensure the same safety and the same angiographic results as the standard procedure. Angiographic results, procedure-related complications, and neurological events during follow-up were recorded. Angiographic follow-up data are available in 36 lesions 6 months after treatment. RESULTS: Forty of 44 aneurysms (91%) could be treated with radioactive coils. Target activities could be reached in 88% of lesions that could actually be coiled (35/40). Total activities ranged from 1.72 to 80.9 microCi, for a mean of 20.13+/-20.80 microCi. Procedure-related complications occurred in 7% of patients. Initial angiographic results were satisfactory (complete occlusions or residual necks) in 75% of lesions. Angiographic recurrences occurred in 11 (31%) of patients followed, within the expected range for standard coils. There was no complication from beta radiation during a mean follow-up period of 10 months. CONCLUSIONS: Radioactive coil embolization is feasible; target volumetric activities can be reached in most aneurysms considered for endovascular treatment.

Adult↗

PubMed1998

A new method for measuring aerosol nebulizer output using radioactive tracers.

Reproducibility and comparability of bronchial challenge tests depends critically on accurate assessment of nebulizer output. Evaporation during nebulization means that simple weighing is inaccurate, overestimating the delivered dose of active ingredient. We wanted to quantify this effect in the context of intermittent nebulization, using a dosimeter as used in bronchial provocation tests. Output of three types of nebulizer, from the MEFAR dosimeter, was measured by radioactive tracer, using a standard solution of technetium-99m-pertechnetate (1.5 kBq x mL(-1)) in 4 mL of normal saline. The aerosol was impacted by suction onto a microfilter, and the radioactivity measured. Nebulizers were weighed before and after nebulization. Ratio of nebulized volume calculated from the radioactivity on the filter, to the total volume loss by weight, was expressed as nebulized ratio. The effect on output of two concentrations of methacholine, two tracers of different weights, and change in temperature, were assessed. Nebulized ratio varied between 44.1-71.6%. Results were more consistent within the same type of nebulizer than between different makes. Neither changes in molar concentration nor molecular weight affected nebulizer output or nebulized ratio. Mean nebulized ratio was 58.5%, showing that calibration by weighing, overestimates the delivered dose by a factor of approximately two. Measuring radioactivity eluted from a microfilter, onto which nebulized output had been impacted proved to be a satisfactory method of calibration.

Aerosols↗

PubMed1990

Distribution of radioactively labelled eltoprazine in rat and dog.

Eltoprazine labelled with 14C either in the phenyl or the piperazine ring was administered orally to rats and dogs. While distribution of radioactivity was not affected by the position of label during the first hours after dosing, from six hours onward concentrations of radioactivity in the organs of rats were higher after [14C]piperazine-labelled eltoprazine. In most organs, radioactivity originating from the [14C]phenyl-labelled compound was detectable up to 72 hours, while [14C]piperazine-labelled material could still be detected 384 hours after dosing. These results suggest that the piperazine ring may be broken down to aliphatic amines which are retained in the body. Quantitatively, however, this is of minor importance, representing about 1% of the dose. With either label, the highest concentrations of the radiolabel were found in liver and kidney. Excretion of radioactivity in rat and dog urine and faeces was not influenced by the position of the radiolabel.

Animals↗

PubMed1980

Metabolism of a new synthetic progestagen, Org 2969, in female volunteers. The distribution and excretion of radioactivity after an oral dose of the labelled drug.

The metabolism of a new synthetic progestagen, Org 2969 was studied in 4 healthy female volunteers. During the first part of the study (Phase I), the volunteers ingested 50 microgram (about 0.1 mCi) of [16-3H5Org 2969 together with 50 microgram of ethinyloestradiol as a single dose. During the second part of the study (Phase II), a 10-day pre-treatment with the same dosage of non-radioactive compound preceded the administration of the radioactive steroid. A peak level of total radioactivity, representing 3.16-5.02% of the dose given/l of serum, was achieved within 2-3 h in Phase I. During Phase II, the corresponding figures were 4.54-5.13% after 1.5-3 h. The difference was mainly due to an increase of freely-extractable steroids during Phase II. The difference can at least partly be explained by assuming a change in the kinetics of the metabolism of Org 2969 by pre-treatment with Org 2969 and ethinyloestradiol. The mean recovery of radio activity in urine and faeces was 83.0%/48.1%/34.9% (total/urine/faeces) of the total dose in Phase I and 76.1%/45.2%/30.9% during Phase II. The differences in the total excretion and in the radioactivity excreted in the faeces were significant.

Administration, Oral↗

PubMed1975

Distribution of radioactivity in the organs of the rat and mouse after injection of (125I)alpha-melanocyte-stimulating hormone.

The distribution of radioactivity after intrajugular injection of 125I-labelled alpha-melanocyte-stimulating hormone (alpha-MSH) was studied by whole-body autoradiography of the mouse and by direct measurement of radioactivity in individual organs of the rat. Very high uptake of radioactivity in the pineal gland was measured 5 min after the injection of (125I)alpha-MSH. Lower levels of accumulation of radioactivity were found in the kidney and in the posterior (including intermediate) lobe of the pituitary. High uptake was also found in the thyroid, stomach, and oesophagus. The specificity of uptake of (125I)alpha-MSH into the pineal and pituitary is suggested by the very low uptake of Na125I into those tissues.

Adrenal Glands↗

PubMed1986

Characterization of radioactivity in plasma after intraduodenal administration of 131I-labelled human cationic trypsin.

Active human pancreatic cationic trypsin labelled with 131I was administered into the duodenum in nine healthy individuals pretreated with "cold", i.e. non-radioactive iodine. Radioactivity in plasma was measured during 72 hours and was present in plasma after 15 minutes with a maximum 1 hour after administration. The recovered radioactivity in plasma was characterized using dialysis and gel-filtration and the radioactive iodine was found to be in the form of free 131I. Our results are in agreement with recent experimental studies indicating the presence of de-iodinases in the intestine. Furthermore, it was found that pretreatment with "cold" iodine prevented isotope binding to circulating plasma proteins.

Adult↗

PubMed1977

Tissue distribution of radioactivity in rats given tritiated analogues of hepatotoxic pyrrolizidine alkaloids.

1. [3H]Retronecine 7,9-bis-N-ethylcarbamate (RC) given intravenously (120 mg/kg) to male rats showed similar tissue distribution of radioactivity to that after an equally hepatotoxic dose (40 mg/kg) of [3H]synthanecine A bis-N-ethylcarbamate (SAC), but the 3H in most tissues after 3H-SAC was about double that after 3H-RC. 2. Concentrations of radioactivity were initially highest in liver and lung, but were higher in lung after 3H-RC than after 3H-SAC, reflecting the higher pneumotoxicity of the former. Concentrations of radioactive metabolites strongly attached to liver tissue were approx. the same 1 day after similarly hepatotoxic doses of either compound. 3. Excretion of radioactivity from 3H-RC was about double that from 3H-SAC in urine, and half that in faeces during the first day.

Animals↗

PubMed1993

Genomic sequencing by ligation mediated polymerase chain reaction using direct blotting and non-radioactive detection.

Genomic sequencing has become an important tool for analyzing uncloned cellular DNA with regard to the methylation status of cytidines as well as to DNA-protein interactions within cells. The hybridization step of the genomic sequencing procedure requires a very high sensitivity, rendering the method fairly difficult. Using a modified ligation mediated polymerase chain reaction procedure (LMPCR) and a sensitive non-radioactive detection method, we have developed a procedure avoiding the high amounts of radioactivity formerly needed for detection of chemically cleaved genomic DNA. The detection limit of our method of genomic sequencing is less than 1 microgram mammalian DNA, which is much better than the detection limit of the original genomic sequencing method and comparable with the detection limit of radioactive detection after the LMPCR procedure. In addition to the advantages of the non-radioactive detection technique we simplified the blotting step of the genomic sequencing procedure by using the direct blotting electrophoresis method. The method was applied to a region 5' to the human c-myc promoter of HeLa cells and was able to verify the sequence obtained by other authors and to specify the methylation status of five CpG-pairs within this sequence.

Base Sequence↗

PubMed1994

Iron-58 and neutron activation analysis: a non-radioactive method for tracing hemoglobin iron.

To develop a non-radioisotopic alternative to radioactive Fe-59 as a hemoglobin iron tracer, we evaluated Fe-58 and neutron activation analysis (NAA). Upon irradiation with thermal neutrons, stable isotope Fe-58 is converted to radioactive Fe-59 through (n,gamma) neutron reaction; its radioactivity measured by a gamma counter is proportional to the original Fe-58 present. Organ samples from rats infused with Hb or saline were analyzed along with a 10 mg Hb as a standard (105 nanograms of Fe-58). The measured values of Fe-58 in tissues were compared with those derived from the literature tissue iron contents. The amount of Fe-58 in normal tissue is extremely low yet detectable by NAA demonstrating high sensitivity. Measured values of Fe-58 from tissues were generally correlated well with literature derived values (e.g., brain: 0.19 and 0.15 ng/mg tissue; kidney: 0.6 and 0.7 ng/mg tissue, respectively). The results indicate that Fe-58 can be used as a non-radioactive tracer for absorption, distribution, metabolism, and distribution studies of hemoglobin-based oxygen carriers.

Animals↗

PubMedDate not supplied

Radioactive iodine therapy: effect on functioning metastases of adenocarcinoma of the thyroid.

A case of metastatic adenocarcinoma of the thyroid is reported in which treatment by means of radioactive iodine has been successful. The patient was completely thyroidectomized for "malignant adenoma" in 1923, with neither thyrotoxicosis then nor hypothyroidism postoperatively; 15 years later there developed classic symptoms of hyperthyroidism and severe pain in the lower back. In October 1939 a pulsating tumor removed from the level of the 12th thoracic vertebra proved to be metastatic thyroid adenocarcinoma (histologically well differentiated, with small follicles and colloid). In the next two years hyperthyroidism increased and roentgenograms revealed new metastases in the lungs, upper part of the right femur, second rib on the left side, left ilium, and skull. Roentgenologic irradiation of the metastases proved ineffectual. In March 1943 a tracer dose of radioactive iodine revealed iodine retention by all the known lesions and no evidence of residual thyroid tissue in the neck. Therapeutic amounts of radioactive iodine were administered orally between May and October 1943. Definite and lasting clinical improvement followed. In April 1944 and March 1945 additional I* was administered with a resultant disappearance of pain, increase in weight, and progressive change in all clinical criteria in the direction of hypothyroidism. Roentgenographic evidence pointed to an arrest if not a regression of the disease. No untoward effects followed this therapy. Radioactive iodine seems to be an effective therapeutic agent in the control of this type of tumor.

Adenocarcinoma↗

PubMed2000

A simple solution to prevent the loss of radioactive spot markers.

OBJECTIVE: Most nuclear medicine technologists have experienced the misplacing and/or the loss of a radioactive spot marker. We report on a simple solution to prevent or at least minimize the loss of radioactive spot markers. METHODS: One end of a metallic beaded chain was attached to the side of 57Co spot marker using repair putty. The other end of the beaded chain was attached to a lead shield that housed the radioactive source when not in use. RESULTS: This design has allowed easy, unobstructed use of the 57Co spot marker for marking the right or left side and anatomical position during imaging while preventing its loss. CONCLUSION: A radioactive spot marker that is attached to a lead shield by a beaded chain is a simple way to prevent its loss while allowing it to be used easily during imaging.

Cobalt Radioisotopes↗

PubMed2000

The role of radioactive iodine in salivary gland dysfunction.

The use of radioactive iodine has become an important adjunct to the treatment of thyroid cancer. Many normal tissues--including salivary glands, gastrointestinal mucosa, gonads, and lactating breast tissue--have the ability to concentrate radioactive iodine under normal circumstances. Although the mechanism is just beginning to be elucidated, it is this ability that might contribute to the immediate and long-term complications associated with radioactive iodine treatment. In some patients, the salivary complications can be permanent and might compromise daily functioning. In this article, we examine the salivary gland complications associated with radioactive iodine therapy, and we suggest potential protective mechanisms to circumvent these problems.

Cytoprotection↗

PubMed2000

Multicolour FISH detection of radioactive iodine-induced 17cen-p53 chromosomal breakage in buccal cells from therapeutically exposed patients.

Simultaneous labelling of 17cen and the p53 locus by multicolour FISH was used to monitor radioactive iodine-induced structural and numerical chromosome abnormalities in buccal cells from 29 hyperthyroidism and thyroid cancer patients sampled before and after therapeutic treatment. This novel methodology allowed the efficient detection of 17p deletions leading to p53 allelic deletions, 17p gains and whole chromosome 17 numerical abnormalities in epithelial cells. Highly significant increases in the frequency of cells with (i) 17p abnormalities (1.8-fold; P < 0.001), including p53 monoallelic deletions (2.1-fold; P < 0.001) and 17p gains (3.5-fold; P < 0.001); (ii) chromosome 17 numerical abnormalities (2-fold; P < 0.001); and (iii) simultaneous 17p breakage and chromosome 17 numerical abnormalities (2.3-fold; P < 0.001), were observed after radioactive iodine treatment. As expected, the major contribution to these increases was detected in hyperthyroidism patients compared with thyroid cancer patients who suffered thyroidectomy before radioactive iodine exposure and, therefore, experienced a rapid elimination of the radioisotope. Considering that both the genetic endpoints and the target tissue are extremely relevant in carcinogenesis, it is suggested that the observed genetic damage could contribute to the reported increase in cancer risk of people therapeutically or accidentally exposed to radioactive iodine.

Adult↗