In vivo nitrosoproline formation and other risk factors in Costa Rican children from high- and low-risk areas for gastric cancer.
The hypothesis that intragastric synthesis of N-nitroso compounds (NOC) in early life could play a role in gastric carcinogenesis was tested by applying the N-nitrosoproline (NPRO) test to about 50 children living in high- and low-risk areas for stomach cancer in Costa Rica. The median values of excretion of NPRO and the sum of three nitrosamino acids (micrograms/12 h urine) were 10-20% of those in adults from other geographical high-risk areas for stomach cancer. The urinary NPRO level after proline intake was higher in children from the high-risk area (P < 0.04) and markedly reduced after ingestion of ascorbic acid together with proline (P < 0.05). NPRO levels on the day of proline intake were highly correlated with levels of nitrate excretion (P < 0.001). Mean levels of total NOC in an aqueous (pH 2) extract of cooked beans from the high- and low-risk areas were similar. Acid-catalyzed nitrosation of the extract increased the total NOC concentration up to 1000-fold, but there was no difference between samples from the two areas. About 10% of bean extracts from both areas showed weak direct-acting genotoxicity in Escherichia coli; after acid-catalyzed nitrosation, all samples were genotoxic at similar levels. The diet of children in the low-risk area satisfied recommended levels of intake of energy and most nutrients except riboflavin and retinol equivalents. Diets from the high-risk area were deficient in energy intake and all nutrients except protein and vitamin C.(ABSTRACT TRUNCATED AT 250 WORDS)
Sierra
R
R
University of Costa Rica, San José.
Chinnock
A
A
Ohshima
H
H
Pignatelli
B
B
Malaveille
C
C
Gamboa
C
C
Teuchmann
S
S
Muñoz
N
N
Bartsch
H
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D001205:Ascorbic Acid / Q000008:administration & dosage; D015415:Biomarkers / Q000652:urine; D002648:Child; D003364:Costa Rica / Q000453:epidemiology; D004032:Diet; D004734:Energy Metabolism; D007887:Fabaceae / Q000737:chemistry; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000652:urine; D009602:Nitrosamines / Q000652:urine*; D009603:Nitroso Compounds / Q000032:analysis / Q000493:pharmacokinetics; D010946:Plants, Medicinal; D011392:Proline / Q000008:administration & dosage; D012307:Risk Factors; D012959:Socioeconomic Factors; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000652:urine
D015415:Biomarkers; D009566:Nitrates; D009602:Nitrosamines; D009603:Nitroso Compounds; D011392:Proline; C010259:nitrosoproline; D001205:Ascorbic Acid