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At least 1,243 records · Page 69Linked to original sources
PubMed1986

In vivo labelling and axonal transport of monoamine oxidase in the rat basal ganglia using radioactive pargyline.

The enzyme monoamine oxidase was labelled in the rat striatum or substantia nigra with locally injected radioactive pargyline. The binding was prevented by a pretreatment with non-radioactive pargyline, or with a combination of clorgyline and deprenyl. Most of the MAO labelled with 3H-pargyline was of the B-type, but also some MAO-A was labelled, as shown in rats pretreated with clorgyline or deprenyl separately. Seven days after the injection of (3H)-pargyline into the striatum a significant labelling was observed in the substantia nigra. This labelling was clorgyline sensitive, indicating type A MAO, and was not present when striatal neurons were destroyed with kainic acid. Labelling of the striatum following 3H-pargyline injection into the substantia nigra was also less in kainate intoxicated striata. Damage of nigral dopamine neurons with 6-hydroxydopamine did not influence the distribution of the label. Thus by using 3H-pargyline, specific labelling and axonal transport of type A MAO in striatal neurons projecting to the substantia nigra was demonstrated.

Animals↗
PubMed1996

Application of the nonradioactive in situ hybridization for the localization of acetylcholinesterase mRNA in the central nervous system of the rat; comparison to the radioactive technique.

In this preliminary report nonradioactive digoxigenine-based and radioactive in situ hybridization procedures for the localization of acetylcholinesterase mRNA were tested and compared in rat brain. General patterns of Ache mRNA localization observed by both techniques did not differ significantly and were practically the same as reported in previous in situ studies on the mammalian brain. Shorter procedure time and avoidance of precautions necessary at work with radioactive materials are major advantages of nonradioactive technique. Under- and over- staining can be prevented by direct examination of coloring reaction. Faint staining in the control experiment with heterologous DNA suggests that proper stringency is essential for the specificity of staining.

Acetylcholinesterase↗
PubMed1980

A single-step method for determination of the specific radioactivity of lipids.

The use of a liquid scintillation counter to measure both the mass and the radioactivity content of charred 14C-labeled lipid bands from thin layer chromatoplates has been evaluated. Following lipid mass determination from a measurement of the external standard channels ratio, a suitable choice of counting parameters enabled a reproducible and efficient 14C count to be obtained over virtually the whole range of lipid concentrations tested. Although the charring procedure resulted in some loss of radioactivity, the efficiency of counting remained high enough for accurate dpm measurements.

Carbon Radioisotopes↗
PubMed1992

One-step synthesis of radioactive acyl-CoA and acylcarnitines using rat liver mitochondrial outer membrane as enzyme source.

Rat liver mitochondrial outer membrane enriched preparations have proven to be a convenient enzyme source for synthesizing coenzyme A (CoA) and carnitine esters of radioactive fatty acids. These membranes are simple to isolate and they retain acyl-CoA ligase and carnitine palmitoyltransferase activities well upon storage. Enzyme purification is not required. A novel aspect of the present procedure is that the same enzymatic incubation step allows both the acyl-CoA and the acylcarnitine esters to be obtained simultaneously when carnitine is present, but produces acyl-CoA ester only when carnitine is not included. Under the conditions described, the conversion of [1-14C]octanoic acid to the respective esters was about 95%; the corresponding figure for [1-14C]palmitic acids was over 70%. The procedure seems suitable for synthesizing the labeled CoA and carnitine esters from a variety of radioactive fatty acids.

Acyl Coenzyme A↗
PubMed1999

Study of implanted biomaterial functionality by diphosphonate molecules labeled with radioactive 99mTc.

An implanted biomaterial can be transformed into young bone after some months, but it has not necessary reached full biofunctionality. Mineral concentration kinetics and crystal-structure studies, still being carried out in our group, are completed here by biofunctionality determinations. A natural coral is implanted in vivo at the cortical level of the femoral diaphyoff++ in rabbits. Diphosphonates molecules labeled with radioactive 99mTc are then injected in rabbits and the fixation of the radioactivity is analyzed in several sites for 8 mo after the implantation. Nuclear instruments and methods are used for the measurements. Four successive cycles of osseous remodeling are determined before reaching a biofunctional phase.

Animals↗
PubMed1999

Relationship between the biodistributions of radioactive metal nuclides in tumor tissue and the physicochemical properties of these metal ions.

This study was undertaken to elucidate the relationship between the biodistribution of radioactive metal nuclides in tumor tissue and its physicochemical properties. Potassium analogs (86Rb, 134Cs, 201Tl) were taken up into viable tumor tissue, although 22Na concentrated in necrotic tumor tissue. 67Ga and 111In were more predominant in inflammatory tissue than in the viable and necrotic tumor tissue. 169Yb and 167Tm accumulated in viable tumor tissue and tissue containing viable and necrotic tumor tissue. 67Ga, 111In, 169Yb and 167Tm were bound to the acid mucopolysaccharide with a mol. wt. of about 10,000 daltons in the tumor tissue. 46Sc, 51Cr, 95Zr, 181Hf, 95Nb, 182Ta, and 103Ru were highly concentrated in inflammatory tissue and were bound to the acid mucopolysaccharides with a mol. wt. exceeding 40,000 daltons. 65Zn and 103Pd concentrated in viable tumor tissue and were bound to the protein in the tissue. The results suggest that the difference in intra-tumor distribution of these elements is caused by a difference in the binding substances (or status) of these elements in the tissues, and the binding substance is determined by physicochemical properties of the elements. We therefore conclude that the biodistribution of radioactive metal ions in tumor tissue is determined by its own physicochemical properties.

Animals↗
PubMedDate not supplied

The kinetics and dynamics of three kinds of radioactive methionine after i.v. administration in mice.

In C57BL mice, a tracer amount of methionine (Met) at a concentration approximate to that in the blood was administered in the tail vein (i.v.). The rates of endogenous metabolic decomposition of methionine were obtained by using three specifically labelled compounds, [1-14C]-Met, [m-14C]-Met and [35S]-Met. Results on the kinetics and dynamics after i.v. administration suggested that 5 min after administration, most of the labelled compounds were taken up into the organs and tissues, and only a small portion was excreted in the expired air as CO2, the final metabolite of methionine. At 30 min the radioactive concentration in blood was minimal and was consistent with the maximum of the 14CO2 excretion in expired air. Gradual increase of the radioactive concentration in blood after 30 min might be due to the contribution of the metabolite in the blood. Methionine taken up was endogenously utilized by more than 40% during 48 h and it maintained the order of [1-14C]:[m-14C]:[35S]. Out of the remaining 60%, 40% was metabolized in 6 h after administration, the [1-14C] moiety being excreted mainly into expired air, the [m-14C] moiety into expired air and urine, and the [35S] moiety mainly into urine and partly into faeces. Microautoradiograms revealed that a part of the last 20% was taken up into the enzyme proteins contained in the pancreatic juice and intestinal juice, and was decomposed within 48 h.

Animals↗
PubMed2003

An imaging co-registration system using novel non-invasive and non-radioactive external markers.

We present a system of image co-registration and its validation in phantom and volunteer studies. The system co-registered images via six novel non-invasive and non-radioactive external markers. The fiducial markers were attached with sponge bases on the skin surface of the phantom and the volunteers in a non-collinear and non-coplanar array. The subjects were scanned with a 1.5-T magnetic resonance (MR) imager using 2D spin-echo T1-weighted (SE) and 3D spoiled gradient recalled pulse sequences (SPGR) and with a positron emission tomography (PET) scanner for transmission imaging (TI) and emission imaging (EI). The sponge bases created radiolucent gaps with good contrast between the fiducial markers and skin surface. They made the markers visible with clear edge boundaries on both PET and MR images. The images to be registered were rescaled, interpolated, reformatted and followed by point-to-point registration for coordinate determination and the estimation of geometrical transformation and fiducial registration errors (FREs) via the fiducial markers. The images formed four matched pairs of inter-modality (SE-TI, SPGR-TI, SE-EI and SPGR-EI) and two pairs of intra-modality (SE-SPGR, TI-EI) imaging for direct co-registration. The parameters for direct co-registration of SE-TI and SPRG-TI were subsequently used as a bridge and applied for indirect co-registration of SE with EI (SE-EI(TI)) and SPGR with EI (SPGR-EI(TI)), respectively. The overall FREs of the phantom were, respectively, 1.50 mm for inter-modality and 1.10 mm for intra-modality direct co-registration. Those of volunteers were, respectively, 1.79 mm for inter-modality and 1.21 mm for intra-modality direct co-registration. For indirect co-registration, the overall FREs of the phantom were 2.53 mm (SE-EI(TI)) and 2.28 (SPGR-EI(TI)) mm; those of volunteers were 2.84 mm (SE-EI(TI)) and 2.81 mm (SPGR-EI(TI)). The errors of direct co-registration were smaller than those of indirect co-registration; the errors of phantom studies, MR-EI and SPGR-PET were smaller than those of the volunteer studies, MR-TI and SE-PET, respectively (all P<0.01, paired-difference test). In conclusion, motion artefacts, imaging blurring and spatial resolution of imaging remained the key factors affecting the accuracy of co-registration. High-accuracy indirect co-registration is provided by using non-invasive and non-radioactive external fiducial markers. The errors were less than 3 mm for both phantom and volunteer studies. The system is applicable for imaging co-registration of inter-modality non-dual imaging, inter-modality multi-tracer imaging and intra-modality multiple parameter images in clinical practice.

Brain↗
PubMed2001

Characteristics of a new fully programmable blood sampling device for monitoring blood radioactivity during PET.

The first performance tests of a new fully programmable blood sampling device for monitoring blood radioactivity during positron emission tomography (PET) are described. Blood is withdrawn through 1-mm internal diameter tubing using an infusion pump which can be operated at rates varying from 0 to 600 ml/h. Activity in blood is measured by a 6-cm-thick bismuth germanate crystal connected to a photomultiplier tube and multichannel analyser (MCA) which are positioned within 6 cm lead shielding. Positioning of the tubing is an exact and simple procedure. The minimal readout time of the MCA is 1 s. Two independent energy windows can be set. Operation of the pump and MCA is fully controlled by a PC, i.e. sampling time, interval time and pump rate can be varied at any time during the PET scan by user-defined scripts. A number of characteristics of the new system were studied, such as sensitivity, dead time, linearity, effect of background radiation and pump rate as a function of input pressure. In addition, dispersion was measured as a function of pump rate. Finally, first clinical results were compared with manual samples. The sensitivity equalled 0.7 and 0.2 cps/Bq for 511- and 1022-keV 30% energy windows, respectively, and the system dead time was 500 ns. The system remained linear within 2% with activity concentrations up to 2.5 MBq/cc. Short-term reproducibility was better than 3% for a 1-h period. Long-term reproducibility was about 5% (ISD), which was mainly caused by variation in the diameter of the tubing. If the device was positioned in such a way that maximum shielding was directed towards the patient, the effects of background radiation from the patient on the measured activity concentration for clinically relevant conditions was minimal (<3%). Pump rate varied with input pressure, but remained constant for a given pressure. Dispersion constants smaller than 0.14 s(-1) were observed for pump rates higher than 300 ml/h, indicating that the system dispersion is small. Clinical data showed an excellent agreement to within 3% (ISD) between the results obtained with the new system and manual samples. With the continuous blood sampler radioactivity in blood can be measured accurately during the entire course of the PET scan. Furthermore, the system is fully programmable allowing adjustment of all parameters during a single PET scan.

Algorithms↗
PubMed1998

A new non-radioactive method for the screening and prenatal diagnosis of myotonic dystrophy patients.

Myotonic dystrophy (DM) is an autosomal dominant neuromuscular disease with an estimated incidence of 1 in 8000 and is the most common form of muscular dystrophy affecting adults. An unstable, untranslated part of the myotonic dystrophy protein kinase gene on the long arm of chromosome 19, composed of CTG repeats, is a genetic marker for DM. We have developed a fast non-radioactive polymerase chain reaction (PCR) procedure to detect the (CTG)n repeat expansion in DM patients and their relatives. Genomic DNA extracted from peripheral blood lymphocytes was amplified by PCR using specific primers to flank the region containing the triplets. To improve the amplification of this CG-rich region, either 10% glycerol or rTth DNA polymerase XL (extra long) was added to the reaction mixture, allowing amplification of huge expansions otherwise not polymerized by PCR. The PCR products were Southern blotted and the expansion revealed using a fluorescein-labelled (CTG)10 probe. We compared our results with those obtained in 24 patients and relatives using genomic digestion followed by radioactive Southern blot; in all cases the results overlapped. The same technique was used for prenatal diagnosis in pregnant DM mothers. We conclude that this new method is reliable for the genetic testing of DM patients.

Adult↗
PubMed2005

A new method for evaluation of radioactive label transport intensity in the predominant direction between blood and liver.

The intensity of (75)Se transport in the predominant direction after intraperitoneal injection of [(75)Se]selenate was compared in 1- and 3-month-old rats receiving common vivarium ration or sucrose diet. The incorporation percent, blood/liver relative radioactivity, and relative radioactivity difference coefficient were evaluated in the blood and liver. The dynamics of label incorporation in the blood of rats fed common diets has two peaks (at 1-3 h and 12-24 h) and a drop at 6 h. Coefficient of difference in 1-month-old rats was characterized by a greater amplitude of fluctuations than in 3-month-old animals.

Age Factors↗
PubMed1995

Regional and arterial localization of radioactive microparticles after local delivery by unsupported or supported porous balloon catheters.

Catheter-mediated intramural delivery of pharmaceutical agents after angioplasty is a potential method to reduce postangioplasty restenosis. The efficacy of such delivery has been limited both by an incomplete initial intramural deposition of delivered agents and by rapid diffusion of soluble agents from the site of delivery. The local delivery of microparticulate agents results in prolonged retention of material at the delivery site. Accordingly this study was designed to evaluate the complementary issue of the initial delivery efficiency and pattern of localization of microparticles after local catheter-mediated delivery with two types of porous balloons. These two types were a "standard" porous balloon (PB) in which hydraulic pressure both inflated the balloon and infused the agents and a porous balloon with a mechanical undergirding that permitted mechanical expansion (PB/ME) before agent infusion. Radioactive cerium 141-labeled microparticles (11.4 microns diameter) were locally delivered into atherosclerotic rabbit femoral arteries after angioplasty to test the hypothesis that use of the PB/ME apparatus would yield enhanced intramural particle deposition and decreased systemic administration by increased balloon-wall contact before microparticle infusion. Six animals underwent infusion with the PB catheter, and seven animals underwent infusion with the PB/ME catheter. An image of the in vivo particle distribution was obtained with a gamma camera during infusion, immediately after infusion, and 1, 3, and 7 days after infusion. Tissue samples from the artery, periadventitia, thigh, calf, and foot musculature, and liver were obtained at animal death, and retained radioactivity was measured with a well counter.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1988

Treatment of non-toxic multinodular goiter with radioactive iodine.

Fourteen patients with large non-toxic multinodular goiters were treated with 20 to 100 mCi (740 to 3,700 MBq) of radioactive iodine (iodine-131). In seven, the goiter had recurred after a partial thyroidectomy and four of these had had two operations. Eight had symptoms of respiratory obstruction, two had dysphagia, and the others sought treatment for cosmetic reasons. After administration of iodine-131, there was a significant decrease in goiter size in 11 of the 14 patients, and all those with obstructive symptoms showed improvement. No significant local side effects occurred, but hypothyroidism and Graves' disease each occurred once during follow-up from one to 13 years. Radioactive iodine in doses of 20 to 100 mCi is an effective, safe therapeutic alternative in patients with large non-toxic multinodular goiter, particularly when there is recurrence following surgery or when there are contraindications to surgery.

Adult↗
PubMed1977

Enhancement of biliary phospholipid radioactivity by intestinal administration of labeled precursors of hepatic lecithin synthesis.

An animal model is used to study the effects of different radioactive precursors of lecithin, administered intestinally, upon biliary lecithin synthesis. Choline caused greater biliary lecithin radioactivity than choline-labeled lecithin or palmitic acid. The clinical application of this finding is discussed with relation to patients with gallstones or potentially lithogenic bile. Oral administration of choline may increase biliary lecithin concentration and, thus, cholesterol-holding capacity in this patient group, thereby changing the character of the bile to a non-lithogenic state.

Animals↗
PubMed1984

Sources of error in estimating radioactivity in protein from cell cultures by liquid scintillation counting.

In this study, several common sample preparation techniques for liquid scintillation counting were critically reviewed. It has been shown that techniques such as NaOH or formic acid solubilization of trichloroacetic acid (TCA)-precipitated proteins led to underestimation of the radioactivity by 20-40%; this loss was not corrected by either internal or external standardization. Hydrolysis of the proteins with 6 N HCl or Pronase significantly increased the recovery of the labeled proteins. Also, 10% of the labeled cell proteins remained on the dish when cells were scraped into buffer; these labelled proteins could be recovered either by in situ hydrolysis with Pronase or by solubilization and scraping in 0.3 N NaOH. These techniques increased the recovered radioactivity by 50-60%, allowing quantitative measurements to be made over a 3-day chase period. A possible mechanism and the implications of this observation were discussed.

Animals↗
PubMed1985

Metabolic labeling of sialic acids in tissue culture cell lines: methods to identify substituted and modified radioactive neuraminic acids.

The parent sialic acid N-acetylneuraminic acid can be modified or substituted in various ways, giving rise to a family of more than 25 compounds. The definitive identification of these compounds has previously required isolation of nanomole amounts for mass spectrometry or NMR. We have explored the possibility of using the known metabolic precursors of the sialic acids, particularly N-acetyl-[6-3H]mannosamine, to label and identify various forms of sialic acids in tissue culture cells. Firstly, we defined several variables that affect the labeling of sialic acids with N-acetyl-[6-3H]mannosamine. Secondly, we have devised a simple screening method to identify cell lines that synthesize substituted or modified sialic acids. We next demonstrate that it is possible to definitively identify the natures of the various labeled sialic acids without the use of mass spectrometry, even though they are present only in tracer amounts. The methods used include paper chromatography, analytical de-O-acetylation, periodate release of the 9-3H as [3H]formaldehyde (which is subsequently converted to a specific 3H-labeled chromophore), acylneuraminate pyruvate lyase treatment with identification of [3H]acylmannosamines, gas-liquid chromatography with radioactive detection, and two new high-pressure liquid chromatography methods utilizing the amine-adsorption:ion suppression and ion-pair principles. The use of an internal N-acetyl-[4-14C]neuraminic acid standard in each of these methods assures precision and accuracy. The combined use of these methods now allows the identification of radioactive tracer amounts of the various types of sialic acids in well-defined populations of tissue culture cells; it may also allow the identification of hitherto unknown forms of sialic acids.

Animals↗
PubMed1988

N-(3-(p-azido-m-[125I]iodophenyl)propionyl)-succinimide--a heterobifunctional reagent for the synthesis of radioactive photoaffinity ligands: synthesis of a carrier-free 125I-labeled cardiac glycoside photoaffinity label.

A new heterobifunctional reagent, N-(3-(p-azido-m-iodophenyl)propionyl)-succinimide (AIPPS), was synthesized and chemically characterized. The radiochemical form of the reagent, [125I]AIPPS, should be of general use as a photoactive reagent for the derivatization of free amino groups on a large variety of biologically active compounds, including many hormones. Amino-containing ligands can be derivatized with [125I]AIPPS in a method which is similar to that used for the 125I-labeled Bolton-Hunter reagent (N-(3-(p-hydroxyphenyl)propionyl)-succinimide). The added advantage with [125I]AIPPS, however, is that the ligand derivative is made both photoactive and radioactive in a single step. As an example of how this reagent can be used, we have prepared carrier-free [125I]AIPPS and reacted it with the amino-containing cardiac glycoside, 4-amino-4,6-dideoxyglucosyl digitoxigenin (GluD). The radioiodinated cardiac glycoside, [125I]AIPP-GluD, was purified by thin-layer chromatography and was carrier-free with a specific radioactivity of 2175 Ci/mmol. [125I]AIPP-GluD was an effective photoaffinity label for Na,K-ATPase as shown by specific photoaffinity labeling of purified canine kidney enzyme and human erythrocyte enzyme.

Affinity Labels↗
PubMed1988

Measurement of specific radioactivity by high-performance liquid chromatograph with a synchronized accumulating radioisotope detector: determination of turnover rate and pool size of tryptophan in rat.

A high-performance liquid chromatograph with a synchronized accumulating radioisotope detector was used to determine the turnover rate and pool size of tryptophan in rat. The specific radioactivity could be followed for three half-lives on the final slope of the specific radioactivity curve following intravenous administration of 15 muCi of carrier free tryptophan labeled with carbon-14. Remarkable individual differences were noted in turnover rate and in pool size among rats.

Animals↗