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  • Inorganic Chemistry  (8)
  • Single-photon emission tomography  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Uptake of iodine-123-α-methyl tyrosine by gliomas and non-neoplastic brain lesions (1996)
    Springer
    European journal of nuclear medicine 23 (1996), S. 1345-1353 
    Details
    ISSN: 1619-7089
    Keywords: Brain neoplasms ; Amino acids ; Iodine-123-α-methyl tyrosine ; Radionuclide imaging ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using single-photon emission tomography (SPET), the radiopharmaceuticall,-3-iodine-123-α-methyl tyrosine (IMT) has been applied to the imaging of amino acid transport into brain tumours. It was the aim of this study to investigate whether IMT SPET is capable of differentiating between high-grade gliomas, low-grade gliomas and non-neoplastic brain lesions. To this end, IMT uptake was determined in 53 patients using the triple-headed SPET camera MULTISPECT 3. Twenty-eight of these subjects suffered from high-grade gliomas (WHO grade III or IV), 12 from low-grade gliomas (WHO grade II), and 13 from non-neoplastic brain lesions, including lesions after effective therapy of a glioma (five cases), infarctions (four cases), inflammatory lesions (three cases) and traumatic haematoma (one case). IMT uptake was significantly higher in high-grade gliomas than in low-grade gliomas and non-neoplastic lesions. IMT uptake by low-grade gliomas was not significantly different from that by non-neoplastic lesions. Diagnostic sensitivity and specificity were 71% and 83% for differentiating high-grade from low-grade gliomas, 82% and 100% for distinguishing high-grade gliomas from non-neoplastic lesions, and 50% and 100% for discriminating low-grade gliomas from non-neoplastic lesions. Analogously to positron emission tomography with radioactively labelled amino acids and fluorine-18 deoxyglucose, IMT SPET may aid in differentiating high-grade gliomas from histologically benign brain tumours and non-neoplastic brain lesions; it is of only limited value in differentiating between non-neoplastic lesions and histologically benign brain tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01367590
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  • 2
    Electronic Resource
    Electronic Resource
    Non-invasive grading of primary brain tumours: Results of a comparative study between SPET with123I-α-methyl tyrosine and PET with18F-deoxyglucose (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 428-434 
    Details
    ISSN: 1619-7089
    Keywords: Brain neoplasms ; Positron emission tomography ; Single-photon emission tomography ; Fluorine-18 fluorodeoxyglucose ; Iodine-123-α-methyl tyrosine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Use of iodine-123-α-methyl tyrosine (123I-IMT) allows investigation of the amino acid transport rate in gliomas. It was the aim of this study to compare the value of measurement of glucose metabolism with that of measurement of123I-IMT uptake for the non-invasive grading of brain tumours. The study population comprised 23 patients with histopathologically proven primary brain tumours; 14 had high-grade gliomas, and nine low-grade brain neoplasms. Glucose metabolism was studied using an ECAT EXACT 47 positron emission tomography (PET) camera and fluorine-18 fluorodeoxyglucose (18F-FDG);123I-IMT uptake was measured with the triple-headed single-photon emission tomography (SPET) camera, MULTISPECT 3.18F-FDG and123I-IMT uptake was quantified as ratios between the uptake by the tumour and contralateral regions of reference. Glucose metabolism and amino acid uptake of the brain tumours correlated significantly (r=0.71,P 〈0.001). Assuming discrimination thresholds between high-grade and low-grade tumours of 0.8 for18F-FDG uptake and 1.8 for123I-IMT uptake, the accuracy values of18F-FDG PET and123I-IMT SPET for differentiating between high-grade and low-grade tumours were 21/23 (91%) and 19/23 (83%), respectively. The difference in diagnostic performance was not significant on receiver operating characteristic analysis (P 〉0.4). It is concluded that there is no major difference between the PET investigation of glucose metabolism and the less expensive SPET measurement of amino acid uptake in terms of their accuracy in evaluating the malignancy grade of primary brain tumours. This encourages the performance of further studies to analyse the potential impact of123I-IMT SPET on the therapeutic management of patients with brain tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00881816
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  • 3
    Electronic Resource
    Electronic Resource
    Reduced GABAA receptor density contralateral to a potentially epileptogenic MRI abnormality in a patient with complex partial seizures (1996)
    Springer
    European journal of nuclear medicine 23 (1996), S. 95-98 
    Details
    ISSN: 1619-7089
    Keywords: Single-photon emission tomography ; Iodine-123 iomazenil ; GABAA receptor ; Epilepsy ; Arachnoid cyst
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Imaging cerebral GABAA receptor density (GRD) with single-photon emission tomography (SPET) and iodine-123 iomazenil is highly accurate in lateralizing epileptogenic foci in patients with complex partial seizures of temporal origin. Limited knowledge exists on how iomazenil SPET compares with magnetic resonance imaging (MRI) in this regard. We present a patient with complex partial seizures in whom MRI had identified an arachnoid cyst anterior to the tip of the left temporal lobe. Contralaterally to this structural abnormality, interictal electroencephalography (EEG) performed after sleep deprivation disclosed an intermittent frontotemporal dysrhythmic focus with slow and sharp waves. On iomazenil SPET images GRD was significantly reduced in the right temporal lobe and thus contralaterally to the MRI abnormality, but ipsilaterally to the pathological EEG findings. These data suggest that iomazenil SPET may significantly contribute to the presurgical evaluation of epileptic patients even when MRI identifies potentially epileptogenic structural lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01736996
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  • 4
    Electronic Resource
    Electronic Resource
    Non-invasive grading of primary brain tumours: results of a comparative study between SPET with 123I-α-methyl tyrosine and PET with 18F-deoxyglucose (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 428-434 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Brain neoplasms ; Positron emission tomography ; Single-photon emission tomography ; Fluorine-18 fluorodeoxyglucose ; Iodine-123-α-methyl tyrosine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Use of iodine-123-α-methyl tyrosine (123I-IMT) allows investigation of the amino acid transport rate in gliomas. It was the aim of this study to compare the value of measurement of glucose metabolism with that of measurement of 123I-IMT uptake for the non-invasive grading of brain tumours. The study population comprised 23 patients with histopathologically proven primary brain tumours; 14 had high-grade gliomas, and nine low-grade brain neoplasms. Glucose metabolism was studied using an ECAT EXACT 47 positron emission tomography (PET) camera and fluorine-18 fluorodeoxyglucose (18F-FDG); 123I-IMT uptake was measured with the triple-headed single-photon emission tomography (SPET) camera, MULTISPECT 3. 18F-FDG and 123I-IMT uptake was quantified as ratios between the uptake by the tumour and contralateral regions of reference. Glucose metabolism and amino acid uptake of the brain tumours correlated significantly (r=0.71, P 〈0.001). Assuming discrimination thresholds between high-grade and low-grade tumours of 0.8 for 18F-FDG uptake and 1.8 for 123I-IMT uptake, the accuracy values of 18F-FDG PET and 123I-IMT SPET for differentiating between high-grade and low-grade tumours were 21/23 (91%) and 19/23 (83%), respectively. The difference in diagnostic performance was not significant on receiver operating characteristic analysis (P 〉0.4). It is concluded that there is no major difference between the PET investigation of glucose metabolism and the less expensive SPET measurement of amino acid uptake in terms of their accuracy in evaluating the malignancy grade of primary brain tumours. This encourages the performance of further studies to analyse the potential impact of 123I-IMT SPET on the therapeutic management of patients with brain tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00881816
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  • 5
    Electronic Resource
    Electronic Resource
    Three-dimensional contour detection of left ventricular myocardium using elastic surfaces (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 201-207 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Myocardium ; Contour detection ; Elastic surfaces ; Positron emission tomography ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Since the human heart has a complex anatomy, the two-dimensional analysis of myocardial scintigrams obviously is not satisfactory. Three-dimensional display can be more easily read by clinicians and depicts more accurately tracer accumulation defects. In this study we propose a three-dimensional myocardial contour detection approach using elastic surfaces. After manual reorientation into short-axis slices and transformation into heart coordinates, the myocardial mid-wall surface passing through the radial activity mass points is calculated using a second-order partial differential equation as a mathematical model. Special considerations are implemented to demarcate organs close to the heart. In a total of 1102 myocardial scintigrams the three-dimensional contour detection calculated a reasonable shape of the left ventricular myocardium in all cases. Even in areas with severe myocardial infarction, this approach was able to bridge tracer accumulation defects. Inter- and intra-observer variability tests confirmed a high reproducibility and user independence. In conclusion, in this study the proposed three-dimensional contour detection of left ventricular myocardium using elastic surfaces was found to be fast, user-independent and reliable, leading to realistic three-dimensional parametric images of myocardial scintigrams that even clinicians not experienced in nuclear cardiology can easily read.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050377
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  • 6
    Electronic Resource
    Electronic Resource
    The clinical impact of thallium-201 reinjection for the detection of myocardial hibernation (1996)
    Springer
    European journal of nuclear medicine 23 (1996), S. 407-413 
    Details
    ISSN: 1619-7089
    Keywords: Hibernating myocardium ; Wall motion ; Revascularization ; Thallium-201 reinjection ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Thallium-201 reinjection improves detection of hibernating myocardium in about 30%–50% of persisting defects. The main goal of cardiac revascularization techniques is amelioration of clinical symptoms such as angina and dyspnoea; however, improvement in regional and global pump function is an additional and important target. The aim of this study was to investigate whether fill-in in the reinjection study is correlated with improved contractile function after treatment (percutaneous transluminal coronary angioplasty/aortocoronary bypass surgery). We studied 32 patients with coronary heart disease and impaired regional wall motion (RWM). RWM and ejection fraction (EF) were assessed by analysing ventriculographic images using the centreline method (values in standard deviations from mean values found in a healthy control group). Three201T1 single-photon emission tomographic studies (stress, redistribution and reinjection) were performed prior to revascularization and analysed using a bull's-eye scheme. Patients were divided into two groups (group FI-=no fill-in,n=16; group FI+=fill-in,n=16). Fifty-six percent of all patients showed persisting defects, and 56% of these defects showed fill-in after reinjection. Fill-in in our patient group was independent of the size of the persisting defects. After revascularization RWM increased significantly in group FI+ (from −1.9 to 0.0 SD,P〈0.001) whereas group FI- showed no significant change (from −1.6 to −1.8 SD). EF increased from −4.3 preoperatively to −2.1 SD postoperatively in group FI+ and did not change significantly in group Fl- (−2.5 to −3.2 SD). The predictive value of reinjection for improvement of RWM was 88%. It is concluded that fill-in in the201Tl reinjection image can predict recovery of RWM and EF after revascularization and should be used in all patients with impaired RWM and persisting defects independent of their extent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01247369
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  • 7
    Electronic Resource
    Electronic Resource
    Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, IX1) Synthese und Reaktivität von Ruthenium(II)-Komplexen mit Ether-Phosphan-Liganden (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1621-1628 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Novel Basic Ligands for the Homogeneous Catalytic Methanol Carbonylation, IX1). -Synthesis and Reactivity of Ruthenium(II) Complexes with Ether Phosphane LigandsThe ether phosphane ligands R2P↷D (2a-d) react with RuCl3·3H2O (1) to give the complexes Cl2Ru(R2P↷D)2 (3a-d) in which the P,O ligands 2a-d function as bidentates. With CO one Ru-O bond is ruptured with formation of trans-Cl2-(R2P∼D)(R2P↷D)RuCO (4a-d). Upon introduction of a second CO molecule in 4a, b, also the other Ru-O bond is cleaved. On heating the kinetically controlled products all-trans-RuCl2(CO)2(R2P∼D)2 (all-trans-5a, b) are transformed into the thermodynamically more stable complexes cis-Cl2(OC)2Ru(trans-R2P˜D)2 (cis,cis,trans-5a, b). All reaction steps are reversible. Upon irradiation cis,cis,trans-5a, b are retransformed into 3a, b via all-trans-5a, b and 4a, b. The opening and closing mechanism of the P,O ligands 2a, b is observed by IR and 31P{1H} NMR spectroscopy. According to X-ray structural analyses, 3b and 4b crystallize in the monoclinic and triclinic space group P21/n and P1 with Z = 4 and 2, respectively. 4b catalyses the hydrogenation of acetaldehyde to ethanol.
    Notes: Die Ether-Phosphan-Liganden R2P↷D (2a-d) reagieren mit RuCl3·3H2O (1) zu den Komplexen Cl2Ru(R2P↷D)2 (3a-d), in denen die P,O-Liganden 2a-d zweizähnig fungieren. Mit CO wird eine Ru-O-Bindung geöffnet unter Bildung von trans-Cl2-(R2P↷D)(R2P↷D)RuCO (4a-d). Bei der Einführung eines zweiten CO-Moleküls in 4a, b läßt sich auch die andere Ru—O-Bindung spalten. Die kinetisch gelenkt entstehenden Produkte all-trans-RuCl2(CO)2(R2P∼D)2 (all-trans-5a, b) wandeln sich beim Erwärmen in die thermodynamisch stabileren Komplexe cis-Cl2(OC)2Ru(trans-R2P∼D)2 (cis,cis,trans-5a, b) um. Alle Reaktionschritte sind reversibel. Beim Bestrahlen wandeln sich cis,cis,trans-5a, b über all-trans-5a, b und 4a, b in 3a, b zurück. Der Auf- und Zuklappmechanismus der P, O-Liganden 2a, b kann IR- und 31P{1H}-NMR-spektroskopisch verfolgt werden. Nach Röntgenstrukturanalysen kristallisieren 3b und 4b in der monoklinen bzw. triklinen Raumgruppe P21/n bzw. P1 mit Z = 4 bzw. 2. 4b katalysiert die Hydrierung von Acetaldehyd zu Ethanol.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871201005
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  • 8
    Electronic Resource
    Electronic Resource
    Bildung siliciumorganischer Verbindungen. XXXI. Synthese des Brme2Si—CH2—Sime2—C≡C—Sime2—CH2-Sime2Br und dessen Abbau mit HBr (1970)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 372 (1970), S. 59-64 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The synthesis of C6H5me2Si—CH2—Sime2—C≡C—Sime2—CH2—Sime2C6H5 (a) is described, which forms Brme2Si—CH2—Sime2—C≡C—Sime2—CH2-Sime2Br(b) with HBr. The reaction of (b) with HBr (1-4 moles at -78°C) yields Brme2Si—CH2—Sime2Br, as well as 1,2-dibromo-ethane (main products) and Brme2Si—CH2/—Sime2CH = CHBr, Brme2Si—CH2—Sime2CH2—CHBr2.
    Notes: Es wird die Synthese des C6H5me2Si—CH2—Sime2—C≡C—Sime2—CH2—Sime2C6H52 (a) beschrieben, das mit HBr Brme2Si—CH2—Sime2—C≡C—Sime2—CH2—Sime2Br(b) bildet. Der Abbau von (b) mit HBr (1-4 Mol bei -78°C) führt zu Brme2Si—CH2—Sime2Br, sowie 1,2-Dibromäthan (Hauptprodukte) und Brme2Si—CH2—Sime2—CH≡CHBr, Brme2Si—CH2—Sime2—CH2—CHBr2.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19703720106
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  • 9
    Electronic Resource
    Electronic Resource
    Bildung siliciumorganischer Verbindungen. XXXVVorbericht: Z. anorg. allg. Chem. 35, 321 (1970;).. Die metallorganische Synthese von Br[(CH3)2Si—CH2]nBr und [(CH3)2Si—CH2]n; n=2-6 (1970)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 377 (1970), S. 37-47 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1. C6H5me2SiCH2Br reacts nearly quantitative with Li to C6H5me2SiCH2Li(I), which reacts with Br(me2Si—CH2)2Br(II) to C6H5(me2Si—CH2)3Br. The compounds C6H5(me2Si—CH2)nBr (III), n = 2,3,4,5,6, are formed according to (a) (see Inhaltsübersicht.)By cleavage with Br2 according to (b) (Inhaltsübersicht) the compounds of group (IV) are obtained.With Li they form cyclic Carbosilanes (me2Si—CH2)n; n = 2, 3, 4, 5, 6.2. (I) reacts with Clme2Si—CH2Br as well C6H5(me2Si—CH2)2Br as C6H5me2Si—CH2Br, as Cl(me2Si—CH2)2Br as C6H5(me2Si—CH2)3Br.The reaction is traced to trans-metallation according to (c) (Inhaltsübersicht). By low temperatures the trans-metallation is promoted. A trans-metallation of the Cl(me2Si—CH2)n Br, n 〉 1, compound was not observed.
    Notes: 1. C6H5me2SiCH2Br bildet mit Lithium fast quantitativ C6H5me2SiCH2Li [I], das sich mit Br(me2Si—CH2)2Br [II] zu C6H5(me2Si—CH2)3Br umsetzt. Die Verbindungen C6H5(me2Si—CH2)nBr [III], n = 2, 3, 4, 5, 6 bilden sich nach (a). Durch Spaltung mit Brom nach (b) Werden die Verbindungen der Gruppe IV erhalten. Sie bilden mit Lithium die cyclischen Carbosilane (me2Si—CH2)n; (n = 2, 3, 4, 5, 6).2. (I) bildet mit Clme2Si—CH2Br neben C6H5(me2Si—CH2)2Br auch C6H5me2Si—CH2Br, Cl(me2Si—CH2)2Br sowie C6H5(me2Si—CH2)nBr. Die Umsetzung ist auf eine Ummetallierung nach (c) Zurückzuführen. Bei niedriger Temperatur (-78°C) ist die Ummetallierung begünstigt. Bei der Verbindung Cl(me2Si—CH2)nBr, n 〉 1, wird die Ummetallierung nicht beobachtet.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19703770106
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  • 10
    Electronic Resource
    Electronic Resource
    Hochdrucksynthesen von Carbonaten. III. Darstellung von Carbonaten zweiwertiger Metalle durch Zersetzung ihrer Oxalate unter hohem CO2-Druck (1980)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 465 (1980), S. 83-91 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: High-Pressure-Synthesis of Carbonates. III. Synthesis of Carbonates of Divalent Metals by Decomposition of their Oxalates under High CO2 PressureThe carbonates MCO3 (M = Mn, Fe, Co, Ni, Zn, Cd) are prepared by decomposition of their oxalates under CO2 pressure up to 3500 bar. The synthesis of CuCO3 runs only in presence of an oxidizing agent. VCO3 · 0,5 H2O is prepared from VCO3 · 2H2O under CO2 pressure. CrCO3 mixed with Cr2O3 arises from Cr(CO)6 under CO2 pressure.
    Notes: Durch Zersetzung ihrer Oxalate unter CO2-Drücken bis 3500 bar werden die Carbonate MCO3 (M = Mn, Fe, Co, Ni, Zn, Cd) erhalten. CuCO3 entsteht nur in Gegenwart eines Oxidationsmittels. VCO3 · 0,5H2O entsteht aus VCO3 · 2H2O unter hohem CO2-Druck. CrCO3 bildet sich im Gemisch mit Cr2O3 aus Cr(co)6 unter CO2-Druck.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19804650109
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