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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 72 (1999), S. M052 
    ISSN: 1432-1246
    Keywords: Key words Azo dye ; Resacor Blue 2F ; C.I. Direct Blue 15 ; 3,3′-Dimethoxybenzidine ; Cytotoxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Azo dyes are widely used in the food, pharmaceutical, cosmetic, textile and leather industries. They can be reduced by azoreductases in intestinal bacteria, liver cells and skin surface microflora so that aromatic amines are released. In this study an analytical system for the determination of carcinogenic aromatic amines at the picogram to femtogram level and a cell culture assay to evaluate the toxicological effects of azo dyes and aromatic amines is presented. For the assays, the commercial azo dye Resacor Blue 2F (Color Index: Direct Blue 15), a 3,3′-dimethoxybenzidine-based dye, was used. The released carcinogenic aromatic amine, 3,3′-dimethoxybenzidine, was extracted with diethylether derivatized with pentafluoropropionic anhydride and analyzed by capillary gas chromatography/mass spectrometry. In addition, the cytotoxicity of Resacor Blue 2F on cultured kidney epithelial cells and on two hepatocyte cell lines (Hep G2 and Chang liver) was evaluated. For this purpose, the cells were exposed for 72 h to varying concentrations of Resacor Blue 2F. The results show that the azo dye inhibits the proliferation of the kidney epithelial cells much more than the proliferation of the two hepatocyte cell lines. As calculated from the dose-response curves, the EC50 (effective concentration reducing cell proliferation by 50%) for kidney epithelial cells was 40 μg/ml, whereas the EC50 for both hepatocyte cell lines was more than 250 μg/ml. Higher concentrations of 3,3′-dimethoxybenzidine were found in kidney epithelial and in Hep G2 culture supernatants; only small amounts were found in the Chang liver culture supernatant. In summary, it was demonstrated that released 3,3′-dimethoxybenzidine was found in the cell culture supernatants, but it did not accumulate within the cells. For an interpretation of the toxicological results, cell-specific transport systems and osmotic effects of the commercial azo dye which contains several inorganic and organic additives has to be considered.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1246
    Keywords: Stereometabolism ; Ethylbenzene exposure ; R- and S-mandelic acid ; Gas chromatography ; Enantiomer separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ethylbenzene is an important industrial solvent and a key substance in styrene production. Ethylbenzene metabolism leads to the formation of mandelic acid, which occurs in two enantiomeric forms, and phenyl-glyoxylic acid. To decide which enantiomer is preferably formed, 70 urine samples of exposed workers were taken at the end of shifts and — after 3-pentyl ester derivatisation — gas chromatographically analysed. The R/S ratio of mandelic acid enantiomers in urine amounts to 19:1, which means that R-mandelic acid is a major metabolite and S-mandelic acid is one of the minor urinary metabolites of ethylbenzene in man. The R/S ratio is independent of ambient air concentration of ethylbenzene within the investigated range. Compared to an ethylbenzene monoexposure the height of total mandelic acid excretion is decreased in the case of coexposure to other aromatic solvents.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 65 (1993), S. S151 
    ISSN: 1432-1246
    Keywords: Biological monitoring ; Butoxyacetic acid 2-Butoxyethanol ; Glutamine conjugate ; High performance liquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine the fraction of butoxyacetic acid (BAA) which is excreted as the amino acid conjugate N-butoxyacetylglutamine (BAA-GLN), urine samples of six lacquerers exposed to 2-butoxyethanol (BE) were collected before and after work and analysed using an HPLC-method which allows the simultaneous quantification of both BAA species. Whereas the pre-shift samples contained only little or no butoxyethanol-related material, concentrations of BAA and BAA-GLN amounted collectively to up to 7 mmol/l in the samples obtained at the end of work. The ratio BAA-GLN vs. total BAA ranged from 0.16 to 0.64 (mean value 0.48) indicating that a substantial fraction of BAA was eliminated as the amino acid conjugate. The results demonstrate that BAA-GLN is an important metabolite of BE in man. Procedures employed for the biological monitoring of exposure to BE should therefore include the quantification of BAA-GLN, otherwise exposure levels would be underestimated.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1920
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Problems of correlating ischemic lesions of the brain with the cerebral vessel involved originate in the axial scanning direction. It is almost impossible to line out precisely the borders of the cerebral lobes-far less are we able to describe exactly the areas supplied by the cortical branches of the anterior or middle cerebral artery. Using a method based on detailed perception of the base of the skull and physiological calculations, it is possible to reconstruct the individual baseline of the scan and to project the outlines of the slices upon the lateral view of the angiogram. Thereby a reliable topographical association between CT findings and angiogram is given.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 18 (1979), S. 103-106 
    ISSN: 1432-1920
    Keywords: Cerebral arterial air embolism ; Arterial embolism on CT ; Esophago-arterial fistula ; Hiatus hernia ; Reflux esophagitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of cerebral air embolism from a rather unusual cause is reported; an esophago-cardiac fistula permitted food particles and air to enter the systemic arterial circulation. Massive embolization caused the patient to become deeply comatose rather suddenly. The computed tomogram (CT) revealed massive cerebral edema with the contradictory finding of wide superficial subarachnoid spaces. These subarachnoid spaces on further evaluation proved to be air in the cerebral vessels.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 16 (1978), S. 332-334 
    ISSN: 1432-1920
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary CT was performed in more than 500 patients with epilepsy. We did not single out any patient group; in about half of the patients seizures are the only symptom, in the remaining group one symptom among others. CT findings allow very clear distinction between different patient groups. The first group contains patients with symptomatic epilepsy and well-defined CT diagnosis like tumors, a.v. angiomas, tuberous sclerosis, etc. A second patient group consists of patients with seizures only which proved to be symptomatic cases too. In the largest group of about 50%, CT was normal; this contained genuine epilepsy and cases of suspected perinatal brain damage, but also cases with later onset epilepsy. Besides cortical atrophy and cystic changes, the most frequent findings in generalized, psychomotoric, and focal seizures were areas of low density without any enhancement effect after i.v. application of a contrast medium. We are quite sure that this collective is inhomogenous too in spite of its uniform CT. The most valid means of discriminating between several pathogenetic conditions will be CT controls and the further clinical course; etiology still remains unknown in most cases. If we could exclude the cases of perinatal brain damage, trauma, postinfectious states, and cerebral ischemia it would be possible to separate a group of patients on which we could concentrate our efforts on the differential diagnosis between gliomas of slow growth, gliosis, or other nontumorous cerebral conditions. The studies will be continued.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 19 (1980), S. 245-248 
    ISSN: 1432-1920
    Keywords: CT scan ; Carotid occlusion ; Watershed infarction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Watershed processes were observed in approximately 40% of cases seen by our study group. In the axial section they mainly appear as stained or striated hypodense areas in white matter of the parietal region, with or without extension into the supply area of adjacent cerebral arteries. These findings can be very subtle and are revealed only by careful examination, especially of higher sections.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 131 (1979), S. 75-79 
    ISSN: 1432-1076
    Keywords: Clover-leaf skull ; Congenital hydrocephalus ; Multiple congenital anomaly syndrome ; CT-investigation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The authors report a detailed CT-investigation of “clover-leaf skull” and compare the findings with cases reported by others.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 11 (1988), S. 313-317 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Major metabolites ; Minor metabolites ; Human urine ; Aromatic solvents ; Biological monitoring ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic solvents are involved in manifold areas of industry and craft. Inhaled solvent vapors are a known health hazard to workers. For medical prevention and toxicological assay specific laboratory methods for urinary metabolites are necessary. An economical capillary gas chromatographic procedure is described which is suitable for routine analysis of major metabolites, sensitive for the determination of minor metabolites, and effective for the separation of chiral metabolic intermediates.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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