Effect of Vicia faba and bran feeding on nitrosamine carcinogenesis and formation.

The goal of this work was to study the effect of the most common Egyptian food items, Vicia faba beans (VF) and bran, on the carcinogenicity of dibutylnitrosamine (DBN) precursors (dibutylamine and nitrite). Mice receiving DBN precursors showed a delayed gain in body weight as well as decreased protein level and 5-nucleotidase activity. Acid ribonuclease, alkaline phosphatase, and DNA level and rate of synthesis were significantly increased compared with corresponding controls. Hepatomas and bladder papillomas developed in 60% and 40% of mice, respectively, after nine months of treatment. On the other hand, administration of VF or bran, in addition to DBN precursors, lessened the damage caused by DBN precursors alone, except DNA level and rate of synthesis were elevated. Alkaline phosphatase was also elevated when bran was administered with DBN precursors. However, these elevations were still less than corresponding elevations in mice receiving DBN precursors alone. The incidence of hepatoma was also reduced to only 20% for both groups. Meanwhile, incidence of bladder papillomas was only 20% in mice receiving VF in addition to DBN precursors, and bladder papillomas were completely absent in mice receiving bran in addition to DBN precursors. In vitro studies were also performed to clarify the effect of VF or bran on diphenylnitrosamine (DPhNA) and its formation from its precursors (diphenylamine and nitrite). The study revealed that VF and bran have the ability to eliminate nitrite and DPhNA from the reaction media and to reduce the rate of formation of DPhNA from its precursors. This reaction depends on the concentration and form of VF or bran and the duration of the reaction. Thus it is concluded that some naturally occurring food items, such as VF and bran, could protect humans against the hazardous effect of nitrosamines and their precursors.

Effect of soybean, Vicia faba, and vitamin C on the carcinogenicity of DMBA.

A single dose of 10 mg of 7,12-dimethylbenz[a]anthracene (DMBA), administered to rats through intragastric intubation, was sufficient to induce many biochemical and histopathological changes in their mammary tissue. Significant increases were observed in the activity levels of the enzymes acid ribonuclease, 5-nucleotidase, alkaline phosphatase, and beta-glucuronidase in mammary tissue homogenates of DMBA-treated rats after an experimental period of five months. Histopathological studies of the mammary tissue also revealed malignant epithelial tumors (cribriform carcinoma) induced among 85% of the treated rats, with an incidence of 4 tumors in 12 mammary glands. Nevertheless, administration of 30% soybean in the diet of rats or 5,000 ppm ascorbic acid in their drinking water in addition to DMBA revealed a significant chemoprotective effect against the carcinogenesis induced by DMBA alone. This chemoprotective effect was demonstrated by the normalization of the activity levels of the enzymes studied in mammary tissue homogenates, because most of the enzymes were maintained at near the levels in the control animals. The incidence and number of tumors were also decreased. Cribriform carcinoma was observed in 50% of the rats, and the incidence of the affected glands was 2 in 12 mammary glands among both groups. On the other hand, a less chemoprotective effect was observed due to Vicia faba administration.

A study on the etiological factors of bilharzial bladder cancer in Egypt: 5-urinary nitrite in a rural population.

Urinary nitrite was present in 5.6% of 2379 individuals from a rural population infested with "Schistosoma haematobium". A higher frequency was observed in symptomatic patients with active bilharzial cystitis (25%) and patients with bladder cancer associated with schistosomiasis (66.2%); conversely, urinary nitrite was absent in normal urban individuals. The frequency of urinary nitrite was higher in females (6.4%) than males (4.6%), and was more frequent in adults than extremes of age. The presence of urinary nitrite was associated with urinary infection and was commonly accompanied by cellular atypia in urine, in the form of dysplasia. Under these circumstances, carcinogenic nitrosamines are liable to be produced in the bladder from urinary nitrite and amines. These observation support the possible role of urinary bacterial infection, commonly associated with bilharzial cystitis, in bladder carcinogenesis.

A new method for determination of inorganic phosphorus in serum without deproteinization.

A simple method was developed for the determination of inorganic phosphorus in serum without deproteinization. The method is based on the use of formic acid as protein solubilizer and glycerol as stabilizer for the assay system. The optimal conditions for colour development were determined. The results obtained with the new method correlate well with those obtained after deproteinization of serum with trichloroacetic acid. The present method could be fully mechanized, and its application to the determination of serum phosphatases is discussed.