Blood protein conjugates and acetylation of aromatic amines

Abstract

Internal stress of aromatic amines has so far been evaluated by their determination in blood or urine and by the degree of methemoglobin formation. Animal experiments have shown that these materials can form adducts and conjugates with proteins and nucleic acids. Our investigations show that these processes can also occur in human metabolism. For this the degree of such a formation of protein conjugates depends on an individually different potential for acetylation. In a positive sense it influences the magnitude and the rate of renal excretion of aminoaromates and their conjugates and metabolites formed by this metabolism. In contrast, only free nonacetylated aminoaromates can lead to the formation of conjugates with hemoglobin. These aminoaromates or their metabolites can then be detected quantitatively in intact erythrocytes during their lifespan. The degree of this protein conjugate formation correlates inversely with the magnitude of the acetylation potential depending on the availability of free non-acetylated aminoaromates. According to these results a clearer assessment of past stress or the presence of strain can be obtained with Biological Monitoring by a single determination of such hemoglobin adducts rather than by the traditional quantitative determination of aminoaromates or their metabolites in blood and/or urine or the methemoglobin concentration.

Measurement Issues in Environmental Epidemiology

“…The Scandinavian countries, however, have mounted a collaborative prospective study of cancer in a cohort of 3190 individuals who have been tested for sister chromatid exchanges (SCEs), structural chromosome aberrations, or both. A report based on a 13-year follow up of 800 subjects in the Finnish portion of the data (49) (51,52). Methodologic needs in the area of effect markers include attention to sources of variability, both biological and laboratory-related, and to logistical issues, such as how to achieve reasonable participation rates when the effect marker requires a demanding regimen.…”

Ubiquitous presence of paracetamol in human urine: sources and implications

“…A similar excretion pattern for aniline can be expected in humans (German Research Foundation 1992). Lewalter & Korallus (1985) found NA4AP (in concentrations up to the mg/l range) and acetanilide (in the mg/l range) in the urine samples of workers following occupational exposure to aniline (air concentrations below the occupational threshold limit of 7.7 mg/m 3 air) (German Research Foundation 1992). NA4AP was also detected as a metabolite after acute aniline intoxication (IwersenBergmann & Schmoldt 2000).…”

Addendum to Nitrobenzene [BAT Value Documentation, 2017]

“…Derivation of this BAT value was based on data obtained by Commission members in occupational health practice during monitoring of employees with occupational exposure to aromatic amines. The results from 250 persons chronically exposed to nitrobenzene and additional 20 cases of acute nitrobenzene intoxication showed that, at MetHb levels up to 5%, always less than 100 μg aniline was released from the haemoglobin conjugate/l whole blood (Lewalter and Korallus 1985). Since then, no new data relevant for evaluation of nitrobenzene have been published.…”