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Single photon radioisotope computed tomography (RCT) images were obtained using the following devices such as conventional gamma camera, data processer for exclusive use of nuclear medicine (C.D.S.-4096), magnetic tape and medium size electronic computer FACOM 230-28S (48K) for multipurposes, which are routinely used for clinical purpose. To reconstruct the RCT image we made absorption correction by geometric mean of opposing counts considering the thickness of source and used the convolution integral method. The reconstructed images of phantom study resolved one centimeter clearly and were very similar to original. The RCT image of patient was acquired by the rotation of patients using the revolving chair and the handmade implement which settles the center of patient's head. Three dimensional informations were obtained by one examination with a gamma camera which collects two dimensional images. When using a gamma camera, therefore, not only a transaxial but an arbitraly RCT image will be important to contribute for diagnosis.  相似文献   

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Synthesis of Nonactin. The macrotetrolide antibiotic nonactin (I), containing four units of a C10 hydroxy acid, has been synthesized starting from two adequately protected derivatives (III and IV) of nonactic acid (II). The 32-membered ring of the macrotetrolide is built up by a sequence of condensation and deprotection steps leading first to a product with two, and subsequently to one with four nonactic acid residues (VIII) which is then cyclized in the presence of Ag+-ions. Two reactions forming ester bonds have been developed to condense the hydroxy acids and to effect the final cyclization. In one the activation of the carboxyl group is achieved by conversion into the mixed anhydride with 2,4,6-trimethylbenzene sulfonyl chloride in pyridine. In the other the Ag+-ion induced reaction of a S-(2-pyridyl) hydroxy carbothioate is used to form the corresponding macrocyclic lactone. In the case of nonactin the ring closure is promoted by the coordinating effect of Ag+-ions present in the reaction mixture.  相似文献   

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The Synthesis of 2,2′-Dinor-carotenoids. 2,2′-Dinor-carotenoids which include the naturally occurring actinioerythrol ( 1 ) and the blue carotenoid violerythrin ( 2 ) have been obtained by total synthesis. The synthesis starts with acetone and acetylene and yields compounds 1 and 2 as well as other carotenoids of the same type.  相似文献   

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Steroid profiles of women suffering from idiopathic hirsutism show in more than 50% of the cases of 10--100 fold increase in the excretion of dehydroepiandrosterone (DHEA) compared with normal values. The excretion of DHEA was reduced much more than that of other 17-ketosteroids if the adrenals (NNR) were suppressed by dexamethasone (DXM). Within one week they reached values at the compound noise level of the gas chromatograms. If the ovaries were stimulated with human chorionic gonadotropin during continued suppression of the NNR with DXM no increase of DHEA could be detected.  相似文献   

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The 1N-TMS-omegan-TFA-derivatives of indolalkylamines are suitable for estimation by combined gas chromatography and mass spectrometry for two reasons, viz. (1) Under electron impact charge stabilisation at the indole nucleus is favoured, so structure-specific ions form the base peak. For unsubstituted indoles m/e values of 202 are found and for hydroxyl-substituted indoles m/e values of 290. (2) The calibration curves of the derivatives are linear, even in the femtomole range. The 1N-TMS-omegan-derivatives can easily be obtained by trimethylsilylation with N-methyl-N-trimethylsilyltrifluoroacetamide containing catalytic amounts of N-trimethylsilylimidazole followed by acylation with N-methyl bis(trifluoroacetamide). The serotonin concentrations in different rat tissues are determined by this method of selective omegaN-trifluoroacylation-1N-trimethylsilylation and compared with the values obtained by pertrimethylsilylation.  相似文献   

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