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W J Mergens

Publications and source records attributed to W J Mergens.

9 recordsLinked to original sources
PubMed1986

Inhibitory effect of alpha-tocopherol on the formation of nitrosomorpholine in mice treated with morpholine and exposed to nitrogen dioxide.

The possibility that alpha-tocopherol (vitamin E) inhibits the formation of nitrosomorpholine (NMOR) in vivo was investigated in mice orally pretreated with alpha-tocopherol (2.5-100 mg/kg body wt) once daily for 6 days. Twenty-four hours later, the animals were injected i.p. with 2 mg of morpholine (MOR) per animal followed by exposure to 47 p.p.m. of NO2 for 2 h. Under these conditions, low oral doses of alpha-tocopherol (2.5-5 mg/kg body wt) significantly decreased NMOR formation in vivo. As total body alpha-tocopherol levels increased, in vivo NMOR formation decreased, and a maximal 50-70% inhibition of NMOR formation occurred at alpha-tocopherol levels of 5 micrograms/g body wt. Additional results showed that NMOR was rapidly eliminated in mice, so that studies which measure the levels of NMOR found in animals treated with MOR and then exposed to NO2 may underestimate the amount of NMOR that is actually formed. Finally, oral pretreatment of up to 100 mg of alpha-tocopherol/kg body wt had no effect on NMOR elimination.

Animals↗
PubMed1984

Formation of N-nitrosomorpholine in mice treated with morpholine and exposed to nitrogen dioxide.

The possibility of N-nitrosomorpholine formation was investigated in mice treated with morpholine and then exposed to 45 p.p.m. nitrogen dioxide in an inhalation chamber for 2 h. Following this treatment, the mice were frozen and pulverized in liquid nitrogen and concentrated extracts from the powders of these animals were analyzed for N-nitrosomorpholine using a thermal energy analyzer interfaced to a gas chromatograph. The data indicate that nitrogen dioxide exposure causes the nitrosation of morpholine in vivo. Additional data show that significant levels of artifactually formed N-nitrosomorpholine are found in control animals that are treated with morpholine after exposure to nitrogen dioxide for 2 h unless a combination of L-ascorbic acid and d,1-alpha-tocopherol are used to inhibit nitrosation during the homogenization, extraction, and analysis of the samples. The need for both a lipid phase nitrosation blocker (d,1-alpha-tocopherol) and an aqueous phase nitrosation blocker (L-ascorbic acid) indicates that the nitrosation of morpholine occurs in both a lipid and an aqueous phase in vitro and therefore may occur in both a lipid and an aqueous environment in vivo. The data from this study also demonstrate the importance of adding suitable inhibitors of nitrosation, such as L-ascorbic acid and d,1-alpha-tocopherol to the extraction solution to prevent possible artifactual formation of N-nitrosomorpholine during the extraction and analysis of the samples.

Animals↗
PubMed1980

The influence of ascorbic acid and DL-alpha-tocopherol on the formation of nitrosamines in an in vitro gastrointestinal model system.

The nitrosation of aminopyrine (4.3 mmol/l) and dimethylamine (4.3 mmol/l) by nitrite (4.3 mmol/l) were studied over the pH range 6-8 in a system containing bile acids and lipid. Both amines were nitrosated to form N-nitrosodimethylamine. The nitrosation of aminopyrine and, to a greater extent, dimethylamine, is enhanced by bile acids. The simultaneous incorporation of ascorbic acid (8.6 mmol/l) and dl-alpha-tocopherol (4.3 mmol/l) was found to be effective in preventing the nitrosation of these two amines. dl-alpha-Tocopheryl acetate was found to be an ineffective blocking agent in this in vitro system.

Aminopyrine↗
PubMed1979

In vitro nitrosation of methapyrilene.

The reactions of sodium nitrite and methapyrilene were studied in aqueous solution at neutral pH and under simulated gastric fluid conditions. Reaction product formation was much more complex than nitrosation of the parent molecule dimethylamino moiety to form nitrosodimethylamine. Several new nitroso compounds were formed under the reaction conditions studied. The simultaneous incorporation of 2 moles of ascorbic acid/mole of nitrite ion prevented any destruction of methapyrilene under all conditions studied. The implications of these observations with respect to nitrosation theory, the general carcinogenicity of nitroso compounds, and methapyrilene dosage formulation are discussed.

Aminopyridines↗
PubMed1978

Alpha-tocopherol: uses in preventing nitrosamine formation.

alpha-Tocopherol has been evaluated as a nitrite scavenger for the prevention of nitrosamine formation in a model system and under practical conditions. alpha-Tocopherol was found to react with nitrosating agents in both lipophilic and aqueous environments. The use of alpha-tocopherol was shown to inhibit aminopyrene-nitrite induced hepatotoxicity in rats and to reduce the amount of NDMA formed in cigarette smoke. Of primary interest is the finding of a significant reduction of NPYR formation in fried bacon. Nitrosamine inhibition was greater with alpha-tocopherol used in combination with sodium ascorbate than with sodium ascorbate alone.

Animals↗