Mutagenicity of diesel exhaust particles from two fossil and two plant oil fuels.

Particulate matter of diesel engine exhaust from four different fuels was studied for content of polynuclear aromatic compounds and mutagenic effects. Two so-called biodiesel fuels, rapeseed oil methylesters (RME) and soybean oil methylesters (SME), were compared directly with two fossil diesel fuels with the normal (DF) and a low sulfur content (LS-DF). Diesel exhaust particles were sampled on filters from the diluted and cooled exhaust of a test engine at five different speeds and loads. Filters were weighed for total particulate matter, Soxhlet extracted with dichloromethane and the content of insoluble material determined. The soluble organic fraction was analysed for polynuclear aromatic compounds. Mutagenicity was determined using the Salmonella typhimurium/mammalian microsome assay with strains TA98 and TA100. Compared with DF, the exhaust particles of LS-DF, RME and SME contained less insoluble material, which consisted mainly of the carbon cores of diesel exhaust particles. The concentrations of individual polynuclear aromatic compounds varied widely among the different exhaust extracts, but total concentrations of the compounds were approximately double for DF and SME compared with LS-DF and RME. In TA98 significant increases in mutation rates were obtained for the soluble organic fractions of all fuels for engines running at full speed (load modes A and D), but for DF revertants were 2- to 10-fold more frequent as compared with LS-DF, RME and SME. Revertant frequencies for DF and partly for LS-DF were also elevated in TA100, while RME and SME gave no significant increase in mutations. The results indicate that diesel exhaust particles from RME, SME and LS-DF contain less black carbon and total polynuclear aromatic compounds and are significantly less mutagenic in comparison with DF. A high sulfur content of the fuel and high engine speeds (rated power) and loads are associated with an increase in mutagenicity of diesel exhaust particles.

[Initial manifestation of disseminated encephalomyelitis: MRT comparative study with established disseminated encephalomyelitis]. / Erstmanifestation der Encephalomyelitis disseminata: MRT-Vergleichsstudie gegenüber gesicherter Encephalomyelitis disseminata.

40 patients with a definite diagnosis and 16 patients with an initial manifestation of multiple sclerosis were investigated by cerebral nuclear magnetic resonance imaging (NMR) and compared. The initial manifestation is predominantly characterized in the NMR by significantly less periventricular involvement, especially within the region of the occipital horns, by significantly rarer appearance of confluent, periventricular lesions within the region of the pars centralis and the temporal horns of the lateral ventricles and by significantly rarer appearance of circumscribed non-periventricular lesions. Unlike those in definite multiple sclerosis, the morphology and distribution of the initial lesions do not show a stereotypical and diagnostically characteristic pattern. The importance of the cerebral NMR for the early diagnosis of multiple sclerosis lies primarily in the indication of disseminated lesions.

[Possibilities and limits of thyroid sonography in the diagnosis of thyroid cancer]. / Möglichkeiten und Grenzen der Schilddrüsensonographie bei der Diagnostik des Schilddrüsenmalignoms.

The echographic appearance of 19 histologically confirmed malignant thyroid tumours has been analyzed. The value of information by ultrasonography is compared to scintigraphy and fine-needle aspiration biopsy. All patients demonstrated a sonographic pattern of relatively low amplitude, sparse and disordered echoes. Extended thyroid tumours (T2-3) exhibited a serrated marginal border as a sign of the infiltration to the surrounding thyroid tissue. The clinically important separation of solid and cystic nodules can always be made with certainty. Provided that a subtile examination technique is used, ultrasonography can be of great value in choosing the adequate therapy in scintigraphic cold nodules. Diagnostic ultrasound also yields information concerning the reliable and reproducible classification and accurate location of circumscribed thyroid lesions. In all cases, however, the ultrasound pattern did not provide reliable clues as to their histology. A successful differentiation between benign and malignant solid nodules can be obtained only by cytology and histology. Ultrasonography, scintigraphy and aspiration biopsy, therefore, are complementary methods.