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International Nuclear Information System (INIS)

Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma rays, often less than 0.1%. A system for small animal SPECT imaging which uses no collimators could potentially achieve very high sensitivity-several tens of percent-with reasonably sized detectors. This would allow two significant improvements in preclinical studies: images could be obtained more rapidly, allowing higher throughput for screening applications, or for dynamic processes to be observed with very good time resolution; and images could be obtained with less radioactive tracer, making possible the in vivo imaging of low-capacity receptor systems, aiding research into ...

International Nuclear Information System (INIS)

Tumor-targeted monoclonal antibodies (mAb) might be useful as diagnostic or therapeutic agents when linked to cytotoxic or imaging reagents. Our group is working to test this hypothesis by linking cytocidal and image-producing isotopes to mAb and testing the utility of the radioimmunoconjugates formed in animal model systems. Radioiodines were first employed for these purposes,but unfavorable nuclear properties (half-lives, #gamma#-ray and #beta#-particle energies) and chemical reactivity (deiodination in vivo) limit their utility. Labeling immunoproteins with metallic radionuclides offers more versatility in that the selection of potentially useful radiometals spans the periodic table.Of the metallic radionuclides with physical properties most suited for use with mAb in nuclear medicine, few are more available or desirable than those of bismuth ("2"1"2Bi) and lead ("2"0"3Pb, "2"1"2Pb), as listed in Table 1. "2"1"2Bi or "2"1"2Pb could serve as sources for highly cytocidal ...

International Nuclear Information System (INIS)

The aim of this report was to assess the usefulness of cerebral blood flow (CBF) scanning utilising the SPECT technique in forensic medicine cases in the area of civil law cases. CBF SPECT scanning was performed in four patients utilising "9"9"mTc-ECD and a triple-head gammacamera. In the analysis both the asymmetry index and cerebellar normalisation were applied. Reference values were obtained by studying 30 healthy volunteers. In those cases CBF SPECT scanning played an important role in forensic argument. It influenced the sentence and the amount of financial compensation. CBF SPECT scanning may provide valuable information in forensic medicine argument in civil law cases, but only when taken together with psychometric tests and other neuroimaging methods (CT, MRI). The value of CBF SPECT scanning alone may be limited in judicial proceedings. (author)

UK PubMed Central (United Kingdom)

BackgroundIn primary hyperparathyroidism (PHPT) the predictive value of technetium 99m sestamibi single emission computed tomography (Tc99m-MIBI-SPECT) for localizing pathological...Full Text Available

KoreaScience (Korea)

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Skeletal radiotracer (sup(99m)Tc-HEDP) uptake was quantitated with and without the aid of a computer in 30 chronic dialysis patients with histologic evidence of renal osteodystrophy. Before scintigraphy, elevated soft-tissue activity due to the absence of renal radiotracer excretion was reduced by hemodialysis. The results were compared with those of a normal group and with the results of the biochemical and the bone morphometric studies of these patients. In all patients the radiotracer uptake was elevated, often markedly. In several patients with minimal histologic bone disease, however, soft-tissue activity could not be normalized by hemodialysis although its influence on the quantitative data could be further reduced (but not excluded) by computer evaluation of skeletal radiotracer uptake. Since the latter technique clearly distinguished the majority of the patients from the normals, it appears that ...

International Nuclear Information System (INIS)

Single photon emission computed tomography (SPECT) of lung perfusions permits to map functioning lung parenchyma with higher sensitivity than CT. Delivering higher radiations doses it used to increase local control in lung carcinoma; this strategy is based on radiobiological and clinical studies. Lung parenchyma is a dose-limiting tissue in patients irradiated for lung cancer. Functional mapping based on SPECT and CT findings permits to design radiation beams such as to minimize irradiation of functioning lung.

UK PubMed Central (United Kingdom)

We have cloned and characterized a 77-kDa oestrogen receptor (ER) from an oestrogen-independent subclone of the MCF-7 human breast cancer cell line. This receptor contains an in-frame, tandem duplication...Full Text Available

International Nuclear Information System (INIS)

It has been five years since the last in-depth American College of Nuclear Physicians/Society of Nuclear Medicine Symposium on the subject of single photon emission computed tomography (SPECT) was held. Because this subject was nominated as the single most desired topic we have selected SPECT imaging as the basis for this year's program. The objectives of this symposium are to survey the progress of SPECT clinical applications that have taken place over the last five years and to provide practical and timely guidelines to users of SPECT so that this exciting imaging modality can be fully integrated into the evaluation of pathologic processes. The first half was devoted to a consideration of technical factors important in SPECT acquisition and the second half was devoted to those organ systems about which sufficient clinical SPECT imaging data are available. With ...

International Nuclear Information System (INIS)

This study aimed to reveal that severe disturbance of attachment relationship with primary care-giver can affect functional and anatomical brain development by measuring cerebral perfusion on "9"9"mTc-ECD brain SPECT and correlative MRI. We included 18 children aged 31 to 76 months who met the diagnostic criteria of RAD as defined in DSM-IV and ICD-10 and SSP and CARS. "9"9"mTc-ECD SPECT was performed using CERASPECT. MRI was performed in all patients. SPECT data were visually assessed. 15 of 18 children had abnormal perfusion on SPECT, revealing decreased perfusion of Lt.thalamus (7/15) and Rt.thalamus (3/15), and bilateral thalami (5/15). Perfusion of basal ganglia was decreased in 8 children. Decreased perfusion of Lt. parietal area was seen in 2. Whereas, all patients had normal MR findings. Perfusion abnormalities involving thalamus, BG in most children with RAD were found in this study. These ...

International Nuclear Information System (INIS)

Coronary angiography provides anatomical information whereas thellium myocardial scintigraphy measures resistive tissue perfusion. Because of this fundamental difference. The authors question the validity of using coronary angiography as the gold standard to judge thellium myocardial scintigraphy. The authors studied 20 patients undergoing elective percutaneous coronary angioplasty who fulfilled the following criteria: (1) history of chest pain; (2) angiographically significant single vessel disease (>50% stenosis); (3) no prior myocardial infarction. All patients underwent maximal exercise thallium single photon emission computed tomography (T1-SPECT). Tl-SPECT was scored visually according to a 0 to 3 scale (0=absent uptake; 1=markedly decreased uptake; 2=minimally decreased uptake; 3=normal uptake). Translesional gradient and percent stenosis were measured before and after angioplasty. The authors found that significant linear ...

UK PubMed Central (United Kingdom)

The LW blood group antigens reside on a 42-kDa erythrocyte membrane glycoprotein that was purified by immunoaffinity and partially sequenced. From this information, a specific PCR-amplified DNA fragment...Full Text Available

UK PubMed Central (United Kingdom)

The cloned 135-kDa CryIC delta-endotoxin from Bacillus thuringiensis is a lepidopteran-active toxin, displaying high activity in vivo against Spodoptera litoralis and Spodoptera frugiperda larvae and...Full Text Available

UK PubMed Central (United Kingdom)

A genomic clone that specifies a single polypeptide precursor for ricin, a toxic lectin of Ricinus communis (castor bean), was isolated, sequenced and Sl mapped. The gene encodes a 64 kDa precursor...Full Text Available

UK PubMed Central (United Kingdom)

Confluent monolayers of microvascular endothelial cells, derived from the rat epididymal fat pad and grown in culture, were radioiodinated by using the lactoper-oxidase method. Their radioiodinated...Full Text Available

UK PubMed Central (United Kingdom)

A compact dedicated 3D breast SPECT-CT (mammotomography) system is currently under development. In its initial prototype, the cone-beam CT sub-system is restricted to a fixed-tilt circular rotation...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Attention deficit hyperactivity disorder (ADHD) has been known as psychiatric disorder in childhood associated with dopamine dysregulation. In present study, we investigated changes in dopamine transporter (DAT) density of the basal ganglias using I-123 N-(3-iodopropen-2-yl) -2-carbomethoxy-3beta-(4-chlorphenyl) tropane (I-123 IPT) SPECT in children with ADHD before and after methylphenidate treatment. Nine drug-naive children with ADHD and seven normal children were included in the study. We performed brain SPECT two hours after the intravenous administration of I-123 IPT and made both quantitative and qualitative analyses using the obtained SPECT data, which were reconstructed for the assessment of specific/nonspecific DAT binding ratios in the basal ganglia. All children with ADHD reperformed (123I)IPT SPECT after treatment with methylphenidate (0.7mg/kg/d) during about 8 weeks. ...

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UO/sub 2/ definitely leaked past the O-ring in three of the tests confirming the major results of the previous work. Continuous leakage at these levels may require additional precautions under present regulatory policies. The mechanism and the time and particle size dependence for the leakage are not known, but there is some indication leakage is more likely at low temperatures. It is possible leakage is due to movement of the O-ring during temperature or pressure cycling at the beginning or end of a test. The radiotracer method involves less labor and is much less susceptible to contamination than the previous method. Future work will investigate leakage past lubricated O-rings and time dependence of leakage. 1 reference, 1 table.

International Nuclear Information System (INIS)

The aim of the study was the attempt to evaluate the influence of two different methods of cardiac perfusion SPECT reconstruction (FBP and ITW) on clinical efficacy in diagnosing the coronary artery disease as well as the cardiac ischemia detection in three areas of heart vascularized by main coronary arteries: LAD, LCX and RCA with the use of artificial neural networks (ANN). The study was performed retrospectively with the use of the diagnostic image records as well as clinical dataset of 43 patients. Myocardial perfusion stress/rest SPECT study and X-ray coronarography data were evaluated for each patient. The results of coronary angiography were considered the reference method. The cardiac SPECT data were reconstructed using the two different methods: filtered backprojection (FBP) and iterative Wallis method (ITW). The local perfusion deficits denominated in stress and rest study in three main vessel cardiac segments ...

International Nuclear Information System (INIS)

Introduction: Previous studies have published the correlation between myocardial perfusion SPECT (MP) during cold pressor test (CPT) and intracoronary acetylcholine and its usefulness as independent marker of endothelial dysfunction (ED). Objective: To analyze the incidence of positivization of MP exercise studies in the follow up of asymptomatic patients with moderate cardiovascular risk (CV) and ED detected by PF. Material and Methods: Of 301 patients of the PARADIGMA Registry (normal exercise MP SPECT and clinical probability < 20% of events at 10 years [moderate risk by Framingham index]) 55 had positive PF (+) (18.3%). Prospectively and consecutively, 15 asymptomatic patients with PF (+), and a control group (CG) of 15 patients with negative PF, with paired sex, age and coronary risk factors (CRF), that accomplished a 12 #+-# 2 months follow up, and that underwent a new exercise and resting MP SPECT were analyzed. ...

International Nuclear Information System (INIS)

Quantitative gated SPECT (QGS) was evaluated in 7 normal volunteers and 31 patients with cardiac diseases. Adequate cut off value of a prefilter was 0.45. In phantom, the left ventricular volume value was 93.9% of determined value by 180-degree projection in L type and 98.8% by 360-degree projection in opposed type. In normal volunteers, LVEF measured by QGS program related to value by first pass method. As for functional map, regional EF and wall motion decreased at the septum side, and wall thickening at base side of heart. Good correlation was recognized (p<0.0001) between blood flow image and functional map (regional EF and wall thickening). In 20 cases of acute myocardial infarction, lesion was detected conspicuously in regional EF and wall motion. The accuracy of coronary arterial stenosis improved in functional map (regional EF 92%, wall motion 92% and wall thickening 88%). In particular, the accuracy of 3 rami lesion was 100% in functional map and higher ...

Energy Technology Data Exchange (ETDEWEB)

Attention deficit hyperactivity disorder (ADHD) is known as a psychiatric disorder in childhood associated with dopamine dysregulation. We investigated dopamine transporter (DAT) density in children with ADHD in the present study using {sup 123}I-IPT SPECT and postulated that an alteration in DAT density in the basal ganglia (BG) is responsible for dopaminergic dysfunction in children with ADHD. 9 durg-naive children with ADHD and 6 normal children were included in the study. We performed brain SPECT 2 hours after administration of {sup 123}I-IPT and made both quantitative and qualitative analyses for assessment of specific/nonspecific DAT binding ratio in the BG. We investigated the correlation between the severity scores of ADHD symptoms in children with ADHD assessed with ADHD rating scale and specific/nonspecific DAT binding ratio in the BG. Drug-naive children with ADHD showed a significantly incresed specific/nonspecific DAT binding ratio ...

Energy Technology Data Exchange (ETDEWEB)

In developing new brain imaging agents for single photon emission computed tomography (SPECT), we synthesized eleven radioiodinated phenoxyacetic acid derivatives and investigated the relationship between the chemical structure and in vivo characteristics. Biodistribution studies in mice revealed high initial brain uptake for all the compounds. Blood radioactivity level depended markedly upon the chemical stability of the compound. The alpha,alpha-dimethylester derivative, amide derivatives and diamine derivatives, which were stable to hydrolysis, showed low blood activity levels following intravenous administration. Disappearance of the ester and amide compounds from the brain was rapid. However, the diamine derivatives displayed improved retention in the brain. Compounds 3a and 4 possessed the best combination of high brain uptake and sufficient retention to be useful as potential brain imaging radiopharmaceuticals with SPECT devices.

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A {lambda}gt11 cDNA library was constructed from poly(U)-Spharose-selected Entamoeba histolytica trophozoite RNA in order to clone and identify surface antigens. The library was screened with rabbit polyclonal anti-E. histolytica serum. A 700-base-pair cDNA insert was isolated and the nucleotide sequence was determined. The deduced amino acid sequence of the cDNA revealed a cysteine-rich protein. DNA hybridizations showed that the gene was specific to E. histolytica since the cDNA probe reacted with DNA from four axenic strains of E. histolytica but did not react with DNA from Entamoeba invadens, Acanthamoeba castellanii, or Trichomonas vaginalis. The insert was subcloned into the expression vector pGEX-1 and the protein was expressed as a fusion with the C terminus of glutathione S-transferase. Purified fusion protein was used to generate 22 monoclonal antibodies (mAbs) and a mouse polyclonal antiserum specific for the E. histolytica portion of the fusion protein. A ...

UK PubMed Central (United Kingdom)

CAP18 (an 18-kDa cationic antimicrobial protein) is a granulocyte-derived protein that can bind lipopolysaccharide (LPS) and inhibit various activities of LPS in vitro. The present study examined the...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundhTERTC27 is a 27 kDa C-terminal polypeptide of human telomerase reverse transcriptase that has previously been shown to reduce tumorigenicity of HeLa cells and suppress...Full Text Available

UK PubMed Central (United Kingdom)

MauG is a novel 42 kDa di-heme protein which is required for the biosynthesis of tryptophan tryptophylquinone, the prosthetic group of methylamine dehydrogenase. The visible absorption and resonance...Full Text Available

International Nuclear Information System (INIS)

Aminophenpyramine, a derivative of mepyramine (pyrilamine), a typical antagonists of histamine at its H_1 receptor was synthesized and converted into ["1"2"5I]iodoazidophenpyramine, a potential photoaffinity probe for the H_1 receptor. In the dark, reversible binding of this probe to cerebellar membranes occurred with a K/sub d/ of 1.2 x 10"-"1"1 M and a B/sub max/ of 240 fmol/mg of protein and was inhibited by various H_1-receptor antagonists with the expected potencies. These features establish the compound as one of the most potent H_1-receptor antagonists known so far. Upon IV irradiation, 5% of the bound radioactivity was covalently incorporated into cerebellar membrane polypeptides as shown by standard NaDodSO_4/PAGE. Two bands of 47 and 56 kDa were consistently labeled, labeling being prevented by various H_1-receptor antagonists with the expected potencies and stereoselectivity. In the presence of protease inhibitors, labeling of the ...

UK PubMed Central (United Kingdom)

The ζ chain-associated 70-kDa protein (ZAP-70) of tyrosine kinase plays a critical role in T cell receptor-mediated signal transduction and the immune response. A high level of ZAP-70 expression...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The behavior of lead in the graphite furnace during the individual steps of the temperature program was investigated by means of /sup 203/Pb as a radiotracer. The matrix systems include HCl and HNO/sub 3/ solutions, 1% NaCl solution, blood, serum, urine, and the solid samples bovine liver and orchard leaves. Without matrix modificaton, a pyrolysis temperature of up to 500/sup 0/C can be used for all samples. Significant stabilization effects can be achieved in the preatomization steps by using NH/sub 4/H/sub 2/PO/sub 4/ and ammonia as matrix modifiers and by addition of hydrogen to the flowing argon gas. It was found that the use of a L'vov platform also helps to eliminate the matrix effects. With respect to lead stabilization and elimination of matrix effects, optimum experimental conditions are achieved by simultaneous use of a L'vov platform and NH/sub 4/H/sub 2/PO/sub 4/ as the matrix modifier. 34 references, 5 figures, 1 table.

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A review is made of the various brain imaging agents utilised in the post few years with their own characters and respective advantages: cerebral blood volume tracers, non diffusible tracers, diffusible tracers among which gases and lipophilic agents. Our results with IAMP and SPECT are presented in two different clinical application fields: normal pressure hydrocephalus and cerebral ischemia.

International Nuclear Information System (INIS)

Scintigraphic imaging of dementia relies today essentially on the study of brain Single Photo Emission Computed Tomography (SPECT) perfusion, after intravenous injection of 99mTc radio-pharmaceutic. This paper is based on the guidelines published in October 2001 by the European Association of Nuclear Medicine (http://eanm.org/). (author)

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Research is described in the development of organometallic reagents in which the boron was attached to a nonreactive organic or inorganic matrix such as polystyrene, silica, or alumina. We developed the synthesis of oxygen-15 labelled butanol, which has been found to be a valuable blood flow agent in humans. We have also developed a series of polymeric borane derivatives which were used to prepare nitrogen-13 labelled amines.

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This book contains 18 selections. Some of the titles are: Labelling of amphetamines with /sup 123/I: Receptors for amphetamines; New amphetamine derivatives; Potential new approaches for the development of brain imaging agents for single-photon applications; and IM SPECT with the pinhole collimator.

International Nuclear Information System (INIS)

Single photon tomography using lipophilic tracers provides tomographic representations of regional blood flow. To penetrate a healthy blood-brain barrier requires that radiotracers either are fat-soluble or have an affinity for one of the selective blood-brain barrier transport systems. In recent years there has been an increasing interest to explore the ideal physical characteristics of "9"9"mTc for diagnostic problems of brain diseases. The development of radiopharmaceuticals for brain imaging including the intensively studied "9"9"mTc-propyleneamineoxime derivatives is discussed. (author).

Science.gov (United States)

Plerocercoids of the tapeworm Spirometra mansonoides produce a substance that stimulates growth of experimental hosts. We report purification of plerocercoid growth factor (PGF) to homogeneity by a process involving isolation and solubilization of plerocercoid membranes, isoelectric point selection by chromatofocusing chromatography or preparative isoelectric focusing, and anion-exchange chromatography. A radioreceptor assay (RRA) for human growth hormone (hGH) was used to detect PGF and purity of the 27.5-kDa protein was judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Proteolytic activity was detected in the 27.5-kDa protein by gelatin substrate PAGE. Characterization of PGF as a neutral cysteine proteinase was based on substrate and inhibitor specificities and dependence on pH and thiol-containing reagents. The association of hGH agonist and proteinase activities was shown by comparing RRA and hydrolytic ...

International Nuclear Information System (INIS)

The crystal structure of outer surface protein A (OspA) from Borrelia burgdorferi contains a single-layer #beta#-sheet connecting the N- and C-terminal globular domains. The central #beta#-sheet consists largely of polar amino acids and it is solvent-exposed on both faces, which so far appears to be unique among known protein structures. We have accomplished nearly complete backbone H, C and N and C";/H"#beta# assignments of OspA (28 kDa) using standard triple resonance techniques without perdeuteration. This was made possible by recording spectra at a high temperature (45 "oC ). The chemical shift index and "1"5N T_1/T_2 ratios show that both the secondary structure and the global conformation of OspA in solution are similar to the crystal structure, suggesting that the unique central #beta#-sheet is fairly rigid.

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Photoaffinity labeling analogs of the adenylate cyclase activator forskolin (PF) have been synthesized, purified and tested for their effect on preparations of membrane-bound, Lubrol solubilized and forskolin affinity-purified adenylate cyclase (AC). All analogs of forskolin significantly activated AC. However, in the presence of 0.1 to 0.3 microM forskolin, the less active forskolin photoaffinity probes at 100 microM caused inhibition. This inhibition was dose-dependent for PF, suggesting that PF may complete with F for the same binding site(s). After cross-linking (125I)PF-M to either membrane or Lubrol-solubilized AC preparations by photolysis, a radiolabeled 100-110 kDa protein band was observed after autoradiography following SDS-PAGE. F at 100 microM blocked the photoradiolabeling of this protein. Radioiodination of forskolin-affinity purified AC showed several protein bands on autoradiogram, however, only one band (Mr = 100-110 kDa) was ...

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Acanthamoeba castellanii myosins IA and IB demonstrate the catalytic properties of a myosin and can support analogues of contractile and motile activity in vitro, but their single, low molecular weight heavy chains, roughly globular shapes, and inabilities to self-assemble into filaments make them structurally atypical myosins. The authors present the complete amino acid sequence of the 128-kDa myosin IB heavy chain, which they deduced from the nucleotide sequence of the gene and which reveals that the polypeptide is a fusion of myosin-like and non-myosin-like sequences. Specifically, the amino-terminal approx. 76 kDa of amino acid sequence is highly similar to the globular head sequences of conventional myosins. By contrast, the remaining approx. 51 kDa of sequence shows no similarity to any portion of conventional myosin sequences, contains regions that are rich in glycine, proline, and alanine residues, and lacks the ...

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The work examines twenty-two patients with coronary artery disease, previous myocardial infarction and LV dysfunction, using the technetium-99m ({sup 99m}Tc) tetrofosmin (SPECT) associated with nitrate administration in the detection of hypoperfused but still viable myocardium. The method allows the detection of this disease. [Italian] Il lavoro analizza i risultati degli esami condotti su 22 pazienti con cardiopatia ischemica cronica e ridotta funzione ventricolare sinistra sottoposti a tomografia computerizzata con emissione di fotone singolo (SPECT) cardiaca con tecnezio-99m ({sup 99m}Tc) tetrofosmina associata alla somministrazione di nitrati nella differenziazione tra tessuto miocardico ipoperfuso ma ancora vitale e tessuto miocardico necrotico. La metodologia usata consente di identificare la presenza di tessuto miocardico vitale in territori vascolari severamente ipoperfusi.

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The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by [sup 201]Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after [sup 123]I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of [sup 123]I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the [sup 201]Tl image and the [sup 123]I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score ([Delta]TUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar ...

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Analytical expressions that describe the dependence of slopes and amplitudes of the scatter distribution functions (SDF) on source depth and media density are used to estimate a scatter component in SPECT projection data. Since the ratio of detected scattered to total photons (S/T), SDF amplitude and slope depend strongly on line source length (SL) used to obtain SDFs, we compared estimated scattered components using SDFs, obtained for lengths of 2-21 cm. At 10 cm source depth, S/T changes from 0.19 to 0.36 when SL changes from 2 to 21 cm. Scatter amplitude`s dependence on source depth (d) in water was described by 6.38e{sup -0.186d} for a 2 cm and 16.15e{sup -0.129d} for a 21 cm SL. Slope was described by 0.292d{sup -0.601} for a cm SL and by 0.396d{sup -0.82} for a 21 cm SL. The estimated scatter components are compared with simulated SPECT projection data obtained with Monte Carlo modeling of six hot spheres placed in a cylindrical water ...

International Nuclear Information System (INIS)

Optional multiple long-axial gated blood pool SPECT images were prepared for the purpose of stereoscopic and quantitative imaging of left ventricular wall motion (LVWM). Sixteen patients with ischemic heart disease and 8 healthy subjects were imaged in 32 views in the 360 degrees position after iv injection of 740 MBq of Tc-99m-labeled human serum albumin D. The R-R interval was divided into 16. After preparing conventional oblique images, long-axial images were prepared. Shortening rate of left ventricular wall was calculated in 5 segments of the apex and base of the left ventricle. An average shortening rate in each segment was graded with a score from a minimum of 0 to a maximum of 40% or more. In the normal group, shortening rate in each segment, except for the base of the septal region, exceeded 40%. In the group of ischemic heart disease, radial shortening was capable of visualizing the degree and extent of the whole LVWM abnormality. LVWM abnormality seen on ...

British Library Electronic Table of Contents (United Kingdom)

Introduction.Microfluidic technology allows fast reactions in a simple experimental setup, while using very low volumes and amounts of starting material. Consequently, microfluidic technology is an ideal tool for radiolabeling reactions involving short-lived positron emitters. Optimization of the complex array of different reaction conditions requires knowledge of the different reaction parameters linked to the microfluidic system as well as their influence on the radiochemical yields. 1-(5-Deoxy-5-fluoro-?-d-arabinofuranosyl)-2-nitroimidazole ([18F]FAZA) is a frequently used radiotracer for PET imaging of tumor hypoxia. The present study describes the radiosynthesis of [18F]FAZA by means of microfluidic technology and subsequent small animal PET imaging in EMT-6 tumor-bearing mice.Methods...

International Nuclear Information System (INIS)

A steadily increasing part of comminution is nowadays carried out by tube ball mills. Our investigations are a first step to a possible tuning of material distribution with mechanical stress characteristic of the grinding media charge, that is essential for a high efficiency of grinding. A BOND mill filled with porcelain balls as grinding media and labelled corundum (Au-198) as grinding material was used to measure the distribution of material over the cross-section. The evaluation was made by linear interpolation between all combinations of adjacent measuring points to calculate all coordinates with equal intensity for each selected level of activity. Two plottings showing the dependence of material distribution on the rotating speed are presented. (author).

Energy Technology Data Exchange (ETDEWEB)

Periphyton is typically a heterogeneous assemblage of filamentous and single celled photoautotrophic and heterotrophic micoorganisms suspended in a mucopolysaccharide matrix which they produce. By definition, the assemblage is attached to a substratum such as rock, sediment, or plant in an aquatic environment. Microtechniques with high spatial and temporal resolution are required to define metabolic interactions among the heterotrophic and autotrophic constituents, and between periphyton and its environment. This study used oxygen sensitive microelectrodes with tip diameters of < 30 m to investigate the effects of photosynthesis and respiration on the oxygen dynamics of several diverse periphyton communities both in situ and in laboratory microcosms. A novel flow-through system that utilized TSP radiotracer and that permitted manipulation of the velocity, flushing rate, and oxygen concentration of overlying water was developed to investigate the role of ...

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A newly-available radioisotopic system, /sup 172/Hf-/sup 172/Lu, has excellent potential for tracer applications in which nuclear data acquisition must be accomplished in real time. The 6.7-day half-life of /sup 172/Lu is sufficient for a large fraction of tracer experiments, and should allow the direct incorporation of /sup 172/Lu into tests that have traditionally utilized much longer-lived radionuclides. Since /sup 172/Lu is the daughter component of a radioisotope generator, however, its effective shelf-life is determined by the half-life of its 1.9-year /sup 172/Hf parent. Consequently, the frequency of isotope procurement need not be any more extensive than investigators would normally be accustomed to. Discussion relevant to isotope production, generator operation, and nuclide acquisition is presented in this paper.

International Nuclear Information System (INIS)

The effect on human health of using food packaging made from recycled materials will depend on whether the elements will migrate into the food itself and at which levels that would be of concern. There is no EU directive for paper and board packaging, but guidelines on paper and board intended to come into contact with food are being developed in another forum. These do not propose limits for paper intended to come into contact with dry foods. However, for other foodstuffs, restriction limits in paper of 0.002 mg/dm"2 (Cd), 0.003 mg/dm"2 (Pb), and 0.002 mg/dm"2 (Hg) have been proposed. This paper describes a radiotracer method that has been applied to the determination of migration of trace elements from paper and board into real food samples.

International Nuclear Information System (INIS)

Radioiodinated carbohydrates such as 2-deoxy-2-iodo-D-glucose and 3-deoxy-3-iodo-D-glucose undergo facile chemical or in vivo deiodination which precludes their use as radiotracers of glucose metabolism in tissues. To overcome the problems resulting from in vivo deiodination, we explored the concept of stabilizing radioiodide on a model carbohydrate, (E)-C-3-iodovinyl-D-allose as an iodovinyl moiety. This agent did not exhibit brain specificity but showed low in vivo deiodination which demonstrated for the first time that radioiodide can be stabilized on a carbohydrate. The goal of this study was to develop a deoxy-branched carbohydrate with radioiodide stabilized as a vinyliodide with the objective of achieving high brain uptake. (author).

Energy Technology Data Exchange (ETDEWEB)

A general method for stable-isotope labeling of large proteins is introduced and applied for studies of the E. coli GroE chaperone proteins by solution NMR. In addition to enabling the residue-specific {sup 15}N-labeling of proteins on a highly deuterated background, it is also an efficient approach for uniform labeling. The method meets the requirements of high-level deuteration, minimal cross-labeling and high protein yield, which are crucial for NMR studies of structures with sizes above 150 kDa. The results obtained with the new protocol are compared to other strategies for protein labeling, and evaluated with regard to the influence of external factors on the resulting isotope labeling patterns. Applications with the GroE system show that these strategies are efficient tools for studies of structure, dynamics and intermolecular interactions in large supramolecular complexes, when combined with TROSY- and CRINEPT-based experimental NMR schemes.

British Library Electronic Table of Contents (United Kingdom)

In order to investigate the antioxidant properties of the polysaccharides from the brown alga Sargassum fusiforme, the crude polysaccharides from S. fusiforme (SFPS) were extracted in hot water, and the lipid peroxidation inhibition assay exhibited that SFPS possessed a potential antioxidant activity. Hence, two purely polymeric fractions, SFPS-1 and SFPS-2 were isolated by the column of DEAE (2-diethylaminoethanol)-Sepharose Fast Flow, with their molecular weights of 51.4 and 30.3 kDa determined by high performance gel permeation chromatography (HPGPC). They were preliminarily characterized using chemical analysis in combination of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies and found to contain large amounts of uronic acids and ?-glycosidical linkages. The antioxida...

British Library Electronic Table of Contents (United Kingdom)

Heme peroxidases are a class of multifunctional redox-active proteins found in all organisms. We recently cloned, expressed, and characterized an ascorbate peroxidase from Leishmania major (LmAPX) that was capable of detoxifying hydrogen peroxide. Localization studies using green fluorescent protein fusions revealed that LmAPX was localized within the mitochondria by its N-terminal signal sequence. Subcellular fractionation analysis of the cell homogenate by the Percoll density-gradient method and subsequent Western blot analysis with anti-LmAPX antibody further confirmed the mitochondrial localization of mature LmAPX. Submitochondrial fractionation analysis showed that the mature enzyme (?3.6?kDa shorter than the theoretical value of the whole gene) was present in the intermembrane space ...

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Abstract Despite the fact that oxidation is the second most frequent degradation pathway for pharmaceuticals, means of evaluating the oxidative stability of pharmaceutical solids, especially effective stress testing, are still lacking. This paper describes a novel experimental method for peroxide-mediated oxidative stress testing on pharmaceutical solids. The method utilizes urea-hydrogen peroxide, a molecular complex that undergoes solid-state decomposition and releases hydrogen peroxide vapor at elevated temperatures (e.g., 30C), as a source of peroxide. The experimental setting for this method is simple, convenient, and can be operated routinely in most laboratories. The fundamental parameter of the system, that is, hydrogen peroxide vapor pressure, was determined using a modified spect...

International Nuclear Information System (INIS)

The effect of X-irradiation on production of MUC1 was studied with human colon carcinoma HT-29 cells. As evaluated by immunocytochemical staining, the percentages or MUC1-positive cells in cells at 4 days after 6 Gy irradiation and in unirradiated control cells were 52#+-#3.5% (n=6) and 26#+-#2.8% (n=6), respectively. Flow-cytometric analysis of living cells showed that MUC1 began to rise from day 1, reaching a plateau by day 4 after 6 Gy irradiation. Western blot analysis with monoclonal antibody MY.1E12 against glycosylated MUC1 (mature form) showed dose-dependent increases of two bands (500 and 390 kDa) corresponding to two polymorphic MUC1 alleles. Premature forms of MUC1 (350 and 240 kDa) were detectable with monoclonal antibody HMFG-2 only in irradiated cells, suggesting that new core protein synthesis had been induced. The transcriptional activity of the MUC1 gene was analyzed in terms of transient expression of MUC1-CAT reporter ...

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Duchenne and Becker muscular dystrophies are caused by defects of dystrophin, which forms a part of the membrane cytoskeleton of specialized cells such as muscle. It has been previously shown that the dystrophin-associated protein A1 (59-kDa DAP) is actually a heterogeneous group of phosphorylated proteins consisting of an acidic ({alpha}-A1) and a distinct basic ({beta}-A1) component. Partial peptide sequence of the A1 complex purified from rabbit muscle permitted the design of oligonucleotide probes that were used to isolate a cDNA for one human isoform of A1. This cDNA encodes a basic A1 isoform that is distinct from the recently described syntrophins in Torpedo and mouse and is expressed in many tissues with at least five distinct mRNA species of 5.9, 4.8, 4.3, 3.1, and 1.5 kb. A comparison of the human cDNA sequence with the GenBank expressed sequence tag (EST) data base has identified a relative from human skeletal muscle, EST25263, which is probably a human ...

International Nuclear Information System (INIS)

Heavy ion irradiation on tantalum metal target with 57 MeV "1"1B"4"+ leads to the production of no-carrier-added radioisotopes of platinum, "1"8"7","1"8"8Pt and iridium, "1"8"7","1"8"8Ir in the matrix, which have been effectively separated from the bulk target and from each other with suitable anion exchangers employing liquid-liquid extraction (LLX). Also "1"8"8","1"8"9Pt and "1"8"8","1"8"9Ir radionuclides have been produced, from their short-lived precursors "1"8"8","1"8"9Au, in "1"2C"6"+ irradiated tantalum matrix. Gamma-spectroscopy has been utilised to determine the production, extent of separation and purity of the radiotracers at different stages of the experiment. (orig.)

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The need for noninvasive sensitive techniques for the diagnosis and follow-up of metabolic bone disease in dialysis patients has stimulated the author's interest in the efficacy of more detailed quantitative bone scintigraphy. Using hemodialysis to reduce elevated soft-tissue activity at scintigraphy, an attempt was made to assess the diagnostic sensitivity of quantitative bone scintigraphy as compared to qualitative bone scintigraphic, biochemical, radiographic and bone histologic studies. The second aim of these studies was to determine if one of the two major components of renal osteodystrophy is a major determinant for skeletal radiotracer uptake. The clinical observations on the efficacy and possible specificity of quantitative bone scintigraphy in the diagnosis and follow-up during treatment of renal osteodystrophy are presented briefly in this chapter. Thus, the use of scintigraphy for the routine detection and follow-up of renal osteodystrophy in dialysis ...

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The interest in radioiodinated diamines stems from their similarity to /sup 125/I-HIPDM and to the 1-dialkvlamino-acyl-4-phenylpiperazines that the authors have previously examined as potential brain imaging agents. In this study they converted the 1-(dialkylaminoacyl)-4-phenylpiperazines to their corresponding 1-(dialkylaminoacyl) analogs via reduction with diborane in THF. Radioiodination at the no-carrier-added level with Na/sup 125/I and chloramine-T gave the final compounds, after chromatographic separation, in 30-50% yields. The tissue distributions were determined in rats at 0.25, and 4 hrs after an i.v. injection of the radiochemical. The results indicated that all of the agents were readily extracted by the brain (1.5-2.5% ID) with brain to blood ratios >20. The structure-distribution relationships for this series were, however, decidedly different from the aminoacyl compounds in that morpholino-derivatives had better uptake and retention than the piperidine derivatives. ...

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Radionuclides exhibiting in decaying a strong interaction between nucleus and electron shell (especially electron capture and internal conversion) are, in principle, sensitive to their chemical surroundings. Consequently, they can be used to yield chemical information after an appropriate labelling procedure. The information can be extracted from the decay rate variation as well as from their X-ray emission as a response to an inner-shell vacancy creation during nuclear deexcitation. As an example of the former method the relationship between the decay rate of /sup 99m/Tc and the chemical structures of pertechnetate and bis(meso-dimercapto-succinate)oxotechnetate(V) is considered. Lower expectations with respect to measuring techniques are associated with the observation of X-ray emission. For a number of elements (especially 3d transition elements) the K/sub ..cap alpha..//K/sub ..beta../ X-ray intensity ratio was found to be an indicator of the nearest neighbour atoms. Equivalent ...

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[sup 123]I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was performed in 20 diabetic patients (NIDDM) and 8 control subjects to investigate the association between clinical autonomic nerve dysfunction and myocardial accumulation of MIBG. We used coefficient variance of R-R interval (CV[sub R-R]) as a index of the autonomic neuropathy and categorized diabetes into two groups (CV[sub R-R][>=]2.0: non-autonomic neuropathy. CV[sub R-R]<2.0: autonomic neuropathy). In planar imaging studies, heart to mediastinum MIBG uptake ratio (H/M) was calculated on both early and delayed images. The washout ratio of [sup 123]I-MIBG in the heart (%WR) was also obtained using myocardial tracer activity on the both images. Mean value of these indices in diabetic group did not reveal any significant difference with the value in the control group. On the SPECT images, low uptake was observed in the posterior-inferior wall with normal uptake of [sup 201]Tl in diabetic ...

International Nuclear Information System (INIS)

Regional cerebral blood flow (rCBF) was assessed with single photon emission computed tomography (SPECT), "1"2"3I-N-isopropyl-iodoamphetamine ("1"2"3I-IMP), and the Table-Look-Up method in 51 children (27 boys, 24 girls) considered neurologically normal and aged 1 month to 15 years (mean age, 4 years 1 month; standard deviation (SD) 3 years 11 months) divided into seven age groups. The rCBF was measured in cortical regions, the cerebellum, thalamus, and the head of the caudate nucleus. Curves for reference values and standard deviations were defined for each region. The rCBF rapidly increased until 2 years of age, reaching maximum values during the third to fifth periods (2 to 10 years of age) in each region. The rCBFs then decreased, reaching adult levels at 10 to 15 years of age. The rCBF reached maximum values later in the frontal region than in other regions. The rCBF during the early period increased most prominently in the occipital region. These results ...

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The ability of Yersinia pestis to forestall the mammalian innate immune response is a fundamental aspect of plague pathogenesis. In this study, we examined the effect of Ail, a 17-kDa outer membrane protein that protects Y. pestis against complement-mediated lysis, on bubonic plague pathogenesis in mice and rats. The Y. pestis ail mutant was attenuated for virulence in both rodent models. The attenuation was greater in rats than in mice, which correlates with the ability of normal rat serum, but not mouse serum, to kill ail-negative Y. pestis in vitro. Intradermal infection with the ail mutant resulted in an atypical, subacute form of bubonic plague associated with extensive recruitment of polymorphonuclear leukocytes (PMN or neutrophils) to the site of infection in the draining lymph node and the formation of large purulent abscesses that contained the bacteria. Systemic spread and mortality were greatly attenuated, however, and a productive adaptive immune ...

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Purpose HER2 is a transmembrane tyrosine kinase, which is overexpressed in a number of carcinomas. The Affibody molecule ZHER2:342 is a small (7?kDa) affinity protein binding to HER2 with an affinity of 22?pM. The goal of this study was to evaluate the use of ((4-hydroxyphenyl)ethyl)maleimide (HPEM) for radioiodination of ZHER2:342 and to compare the targeting properties of monomeric and dimeric forms of ZHER2:342. Methods The biodistribution of different radioiodinated derivatives of ZHER2:342 was studied in BALB/C nu/nu mice bearing HER2-expressing SKOV-3 xenografts. Biodistributions of 125I-PIB-ZHER2:342 and site-specifically labelled 125I-HPEM-ZHER2:342-C were compared. Biodistributions of monomeric 131I-HPEM-ZHER2:342-C and dimeric 125I-HPEM-(ZHER2:342)2-C were evaluated using a paire...

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Low expression of osmotically responsive genes 2 (LOS2) encodes an enolase (2-phospho-D-glycerate hydrolase, EC 4.2.1.11) that converts 2-phospho-D-glycerate (PGA) to phosphoenolpyruvate (PEP) in the glycolytic pathway in Arabidopsis. Meanwhile, it is a transcriptional activator of cold-responsive gene, negatively controlling the expression of STZ/ZAT10, a zinc finger transcriptional repressor of cold-responsive gene from Arabidopsis. A novel LOS2 gene, designated PtrLOS2 (GenBank accession number GQ144341), was isolated from trifoliate orange [Poncirus trifoliata (L.) Raf.]. The PtrLOS2 cDNA is 1 662 bp in length with a 1 338 bp open reading frame (ORF), encoding a deduced 445 amino acid residue protein with a predicted molecular mass of 47.79 kDa and an isoelectric point of 5.54. The ded...

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Abstract Plant annexins represent a multigene family involved in cellular elongation and development. A cDNA encoding a novel annexin was isolated from a cotton (Gossypium hirsutum) fiber cDNA library and designated-GhAnx1. This gene encodes a 316 amino acid protein with a theoretical molecular mass of 36.06 kDa and a theoretical pI of 6.19. At the amino acid level, it shares high sequence similarity and has evolutionary relationships with annexins from higher plants. The purified recombinant protein expressed in-Escherichia coli-was used to investigate its physicochemical properties. Circular dichroism spectrum analyses showed a positive peak rising to the maximum at 196 nm and a broad negative band rounding 215 nm, suggesting that the GhAnx1 protein was prominently -helical. The fluoresc...

Science.gov (United States)

We have constructed a 27-kDa hTERT C-terminal polypeptide (hTERTC27) devoid of domains required for telomerase activity and demonstrated that it is capable of nuclear translocation/telomere-end targeting. Here we showed that expression of a low level of hTERTC27 renders hTERT positive HeLa cells sensitive to H(2)O(2)-induced oxidative stress and subsequent cell senescence. The senescence-associated gene, the cyclin/cdk inhibitor p21(Waf1), was up-regulated. This occurs without changing the expression of endogenous hTERT, causing significant telomere shortening or inhibiting telomerase activity. Results from this study suggest for the first time that in addition to telomerase activity, the C-terminus of hTERT also plays a role in hTERT-mediated cellular resistance to oxidative stress. PMID:12565825

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Since chlordecone (Kepone, CD) interferes with cardiac Na{sup +} ion translocases, we have studied CD effects on cardiac SR calcium pump activity. SR was isolated from heart ventricles of male Sprague-Dawley rats. Cardiac SR Ca{sup 2+}-ATPase, {sup 45}Ca-uptake and cAMP as well as calmodulin (CaM) dependent protein phosphorylation were measured. Ca{sup 2+}-ATPase was differentiated into low affinity and high affinity forms by measuring the activity using 50 and 0.7 {mu}M free Ca{sup 2+} respectively. CD in vitro inhibited {sup 45}Ca-uptake by SR in a concentration dependent manner with an IC50 value of 7 {mu}M and SR {sup 45}Ca-uptake was totally inhibited at 20-30 {mu}M CD. In agreement with this, both high affinity and low affinity Ca{sup 2+}-ATPases, which are involved in Ca{sup 2+} transport across membranes, were also inhibited by CD in a concentration dependent manner with IC50 values of 0.7 and 3.2 {mu}M respectively. Both Ca{sup 2+}-ATPase and {sup 45}Ca-uptake by cardiac SR ...

International Nuclear Information System (INIS)

Technetium-99m was previously shown to form a stable, neutral and lipopholic complex with propylene amine oxime, PnAO. This Tc-99m-PnAO complex was shown to efficiently extracted by normal brain. However, it is not sufficiently retained in the brain to image its cerebral distribution using convertional SPECT (single-photon emission computerized tomography) instrumentation. A number of derivatives of PnAO have been synthesized and their technetium-99m complexes have been biologically evaluated. A number of these have been shown to have high brain uptake without exhibiting the rapid cerebral clearance that was observed with Tc-99m-PnAO. To better understand the chemistry of these potential brain imaging agents, a number of technetium-99 complexes of derivatives of PnAO have been synthesized and characterized. Substituents on the tetradentate amine oxime backbone were varied to probe the effect(s) of these structural changes on the properties of the resultant Tc(V) ...

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In developing new Tc-99m brain perfusion imaging agents for SPECT, a series of BAT (bis-aminoethanethiol) derivatives was prepared. These N/sub 2/S/sub 2/ ligands formed stable and neutral complexes with reduced Tc-99m, either by Sn(II)-PPi or sodium borohydride reduction. The purity of the Tc-99m complexes was >95% (HPLC reverse-phase column, acetonitrile: pH 7.0 buffer, 85:15). The biodistribution in rats was evaluated using I-125 iodoantipyrine (IAP), a free diffusible tracer, as the internal reference. Compounds with a free hydroxyl group (I and IV) showed lower brain uptake, inspite of high P.C.; this may be related to in vivo instability of the complexes. High initial brain uptake was observed for three compounds (II, III and V), however, only compound V (P.C.=384) showed significant brain retention. Planar imaging with compound V in a monkey demonstrated that the compound localized in brain and the retention time was T/sub 1/2/=35 min. Compounds of this ...

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Hepatobiliary scintigraphy is the only non-invasive technique providing real-time assessment of hepatocytes function and bile progression from the liver to the intestine; for this reason it is of great importance in the study of jaundice and many other disorders of the liver and the biliary tract in children. Ultrasonography is the initial method of evaluating the intra- and extrahepatic bile ducts dilatation: the differential diagnosis between biliary atresia and neonatal hepatitis cannot however be done without hepatobiliary scintigraphy. Cystic fibrosis patients also require hepatobiliary scintigraphy; liver and biliary tract disease can really occur independently of the underlying disease severity and the presence of steatorrhoea. Hepatobiliary imaging in children who have undergone liver transplantation is of major importance; it can assess vascularity, parenchymal function biliary drainage, possible presence of a bile leak and obstruction; it has very good sensitivity and ...

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In the search for new brain imaging agents for use with single photon emission computed tomography (SPECT), quantitative structure activity relationship (QSAR) analysis of the correlations between initial brain uptake and physicochemical parameters like lipophilicity, log P, molecular weight, log MW and log U/D (undissociated/dissociated), of the {sup 99m}Tc-DADT (diaminedithiol) complexes and {sup 99m}Tc-PAO (propyleneaminoxime) complexes have been analyzed. High correlations are found for both the {sup 99m}Tc-DADT complexes (r = 0.94) and for the {sup 99m}Tc-PAO complexes (r = 0.83) which are significant at 99.9 and 99.5 percentile level, respectively. These results will help the further design of better ligands for {sup 99m}Tc in brain imaging. (author).

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We labelled Lipiodol with yttrium-90 and analysed the biodistribution in rats after intrahepatic arterial injection. An RP-18 column was used to separate {sup 90}Y from strontium-90. {sup 90}Y was retained on the column, which had been pretreated with yttrium-selective extraction reagent, di(2-ethylhexyl) phosphate, while {sup 90}Sr was washed out. A hexadentate nitrogen-donor chelating ligand N,N,N`,N`-tetrakis(2-benzymidazolylmethyl)-1,2-ethanediamine (EDTB) was synthesized by condensation of 1,2-benzenediamine and ethylene diamine tetra-acetic acid (EDTA). Lipiodol was covalently conjugated with EDTB. The final product was obtained by eluting the retained {sup 90}Y from the RP-18 column with EDTB-Lipiodol. Sixteen male rats (Sprague-Dawley) were sacrificed at 1 h, 24 h, 48 h and 72 h (four rats at each time) after injection of approximately 0.1 mCi {sup 90}Y-Lipiodol via the hepatic artery. Samples of liver, spleen, muscle, lung, kidney, bone, whole blood and testis were obtained ...

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Bone formation and resorption have been measured in patients with idiopathic osteoporosis by histomorphometry of 7.5-mm trephine biopsies and in the whole body by 85Sr radiotracer methodology and calcium balances. The studies were synchronized and most were preceded by double in vivo tetracycline labeling. Correlations between histological and kinetic bone formation indices were better when better when based on the extent of double tetracycline labels than on measurements of osteoid by visible light microscopy. Correction of the kinetic data for long-term exchange, using 5 months' serial whole body counting of retained 85Sr, improved the fit of the kinetic to the histological data. A statistical analysis of the measurement uncertainties showed that the residual scatter in the best correlations (between exchange-corrected bone formation rates and double-labeled osteoid surface indices) could be attributed to measurement imprecision alone. The ...

International Nuclear Information System (INIS)

Three cDNAs, designated IIA3, IIA3v, and IIA4, coding for P450s in the CYP2A gene subfamily were isolated from a #lambda#gt11 library prepared from human hepatic mRNA. Only three nucleotide differences and a single amino acid difference, Leu"1"6"0#->#His, were found between IIA3 and IIA3v, indicating that they are probably allelic variants. IIA4 displayed 94% amino acid similarity with IIA3 and IIA3v. The three cDNAs were inserted into vaccinia virus, and recombinant viruses were used to infect human hepatoma Hep G2 cells. Only IIA3 was able to produce an enzyme that had a reduced CO-bound spectrum with a #lambda#_m_a_x at 450 nm. This expressed enzyme was able to carry out coumarin 7-hydroxylation and ethoxycoumarin O-deethylation. cDNA-expressed IIA3v and IIA4 failed to incorporate heme and were enzymatically inactive. Analysis of IIA proteins in human liver microsomes, using antibody against rat IIA2, revealed two proteins of 49 and 50 kDa, the former of ...

Science.gov (United States)

From the dried fruiting bodies of the mushroom Armillaria luteo-virens, a dimeric lectin with a molecular mass of 29.4 kDa has been isolated. The purification procedure involved (NH{sub 4}){sub 2}SO{sub 4} precipitation, ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. The hemagglutinating activity of the lectin could not be inhibited by simple sugars but was inhibited by the polysaccharide inulin. The activity was stable up to 70 {sup o}C but was acid- and alkali-labile. Salts including FeCl{sub 3}, AlCl{sub 3}, and ZnCl{sub 2} inhibited the activity whereas MgCl{sub 2}, MnCl{sub 2}, and CaCl{sub 2} did not. The lectin stimulated mitogenic response of mouse splenocytes with the maximal response achieved by 1 {mu}M lectin. Proliferation of tumor cells including MBL2 cells, HeLa cells, and L1210 cells was inhibited by the lectin with an IC{sub 5} of 2.5, 5, and 10 ...

International Nuclear Information System (INIS)

The active site of chicken gizzard myosin was labeled by direct photoaffinity labeling with ["3H]UDP. ["3H] UDP was stably trapped at the active site by addition of vanadate (Vi) and Co"2"+. The extraordinary stability of the myosin.Co2+.[3H]UDP.Vi complex (t1/2 greater than 5 days at 0 degrees C) allowed it to be purified free of extraneous ["3H]UDP before irradiation began. Upon UV irradiation, greater than 60% of the trapped ["3H]UDP was photoincorporated into the active site. Only the 200-kDa heavy chain was labeled, confirming earlier results using ["3H]UTP. Extensive tryptic digestion of photolabeled myosin subfragment 1 followed by high performance liquid chromatography separations and removal of nucleotide phosphates by treatment with alkaline phosphatase allowed two labeled peptides to be isolated. Sequencing of the labeled peptides and radioactive counting showed that Glu185 was the residue labeled. Since UDP is a zero-length cross-linker, Glu185 is ...

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Three regio-isomers of N-(N-benzylpiperidin-4-yl)-4-iodobenzamide, IBP, were prepared and evaluated for their sigma affinities. All three isomers (2, 3, and 4-substituted) showed high affinities for sigma-1 receptors in guinea pig brain membranes (Ki - 1.64 nM, 3.02 nM, 1.70 nM respectively) against ["3H]-(+)-pentazocine, a sigma-1 selective ligand. 2-IBP and 4-IBP showed modest affinities for sigma-2 sites in rat liver (Ki = 29.6 nM. 25.2 nM respectively) against ["3H]DTG in the presence of dextrallorphan to mask sigma-1 sites. The homologous competition binding studies of 4-["1"2"5I]BP in MCF-7 human breast tumor cells showed high affinity dose-dependent binding. Competition binding studies with haloperidol and DTG also showed a high affinity binding (Ki = 4.6 nM, 60 nM respectively), demonstrating the sigma specificity. The saturation binding (Scatchard analysis) of ["3H]DTG with MCF-7 cell membrane preparations gave Kd of 24.54 nM and a Bmax of 2071 fmol/mg protein. These results ...

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The radioiodination and in vivo evaluation of p-iodocaramiphen a muscarinic antagonist which binds with high affinity to the M[sub 1] receptor subtype in vitro are described. Biodistribution studies in female Fischer rats demonstrated that [[sup 125]I]-piodocaraminphen had significant cerebral localization, but the uptake did not demonstrate specific uptake in those cerebral regions rich in muscarinic receptors, and radioactivity washed out rapidly from the brain. In addition there was no significant blockage of activity when the rats were preinjected with quinuclidinyl benzilate. These results suggest that p-iodocaramiphen is not a good candidate for the in vivo study of M[sub 1] muscarinic receptor populations by SPECT. Because of the widespread interest and expected importance of the availability of large amounts of tungsten-188 required for the tungsten-188/rhenium-188 generator systems, we have investigated the large-scale production of tungsten-188 in the ...

International Nuclear Information System (INIS)

Neurotensin (NT) and its high affinity receptor (NTR1) are involved in several neoplastic processes. Thus, NT-based radiopharmaceuticals are potential tracers for targeted diagnosis and therapy of NTR-positive tumours. A new analogue based on NT(8-13), NT-XIX, with the three enzymatic cleavage sites stabilised, was synthesised and tested. The synthesis was performed by Boc strategy. Labelling with "9"9"mTc/"1"8"8Re was performed using the tricarbonyl technique. Metabolic stability was tested in vitro and in vivo. NT-XIX was further characterised in vitro in HT-29 cells and in vivo in nude mice with HT-29 xenografts. NT-XIX showed much longer half-lives than non-stabilised analogues. Binding to NTR1 was highly specific, although the affinity was lower than that of natural NT. Bound activity rapidly internalised into HT-29 cells and 50% remained trapped after 24 h. In the time-course biodistribution, the highest uptake was found in the tumour at all p.i. times. In vivo uptake was ...

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Nuclear medicine and magnetic resonance imaging (MRI) are widely used in cardiac diagnostics. Both techniques have been carefully evaluated and are equivalent for the assessment of regional and global wall motion as well as the evaluation of ejection fraction and cardiac volumes, though MRI is herein currently seen as gold standard. For evaluation of myocardial perfusion, extensive data exist for nuclear imaging, that, next to high diagnostic accuracy for evaluation of coronary artery disease, show incremental prognostic information and allow for independent risk stratification. Because of rapid technical advance, myocardial perfusion imaging has also become feasible with cardiac MRI. Results of recent studies are promising, but the data are few compared to perfusion scintigraphy. For viability assessment in patients with ischemic cardiomyopathy, positron emission tomography (PET) with FDG is currently seen as gold standard. However, single photon emission computed tomography ...

International Nuclear Information System (INIS)

Aim: There has been a great demand for developments of the radioligands to visualize the N-methyl-D-aspartate (NMDA) receptors by PET/SPECT. We have recently synthesized two C-11 labeled antagonists for the glycine-binding site on NMDA receptors. The aim of this work is to examine for their in vitro and in vivo binding characteristics, and to evaluate their potentials as PET radioligands for the NMDA receptors. Materials and methods: Two C-11 labeled 4-hydroxy-2-quinolones (1 and 2) were synthesized by conventional methylation of the corresponding phenols with ["1"1C]methyl iodide. In vitro and ex vivo quantitative autoradiographs with imaging plate, as well as animal PET, were employed in order to evaluate their in vitro and in vivo binding to the NMDA receptors. Results: The compound 1 showed the specific binding to rat brain slices with higher localization in the hippocampus and cerebral cortex than in the cerebellum. Both glycine antagonists and agonists ...