Abnormal Savda Munziq, an Herbal Preparation of Traditional Uighur Medicine, May Prevent 1,2-dimethylhydrazine-Induced Rat Colon Carcinogenesis.

The study tried to assess the chemoprotective effect of abnormal Savda Munziq (ASMq) on 1,2-dimethylhydrazine (DMH)-induced rat colon carcinogenesis. Male F344 rats were randomized into eight groups: Group 1 was served as control, no DMH injection was given and treated daily with normal saline. Rats in Groups 2-8 were given a single intraperitoneal injection of DMH (20 mg/kg body weight) at the beginning of the study.

Synergic effect of vitamin A and high-fat diet in adipose tissue development and nuclear receptor expression in young rats.

In order to study the effects of dietary lipids and vitamin A on the development of adipose tissues, young rats were submitted for 8 d to a control or to two cafeteria diets with normal (Caf) or higher (Caf + ) vitamin A levels. Retinoid (retinoic acid receptor (RAR) a, RARg, retinoid X receptor(RXR) alpha) and fatty acid (PPARgamma) receptor mRNA was measured in the subcutaneous white adipose tissue (Swat) and in isolated mature adipocytes by RT-PCR. The stroma vascular fraction was cultured in vitro to test the capacities of the adipocyte precursors to proliferate and differentiate.

The effect of body weight on altered expression of nuclear receptors and cyclooxygenase-2 in human colorectal cancers.

Background: Epidemiological studies on risk factors for colorectal cancer (CRC) have mainly focused on diet, and being overweight is now recognized to contribute significantly to CRC risk. Overweight and obesity are defined as an excess of adipose tissue mass and are associated with disorders in lipid metabolism. Peroxisome proliferator-activated receptors (PPARs) and retinoid-activated receptors (RARs and RXRs) are important modulators of lipid metabolism and cellular homeostasis.

A high-fat diet generates alterations in nuclear receptor expression: prevention by vitamin A and links with cyclooxygenase-2 and beta-catenin.

Epidemiologic studies suggest that intake of high energy from fat, inducing overweight, increases the risk of cancer development and promotes colon carcinogenesis. It is therefore important to understand which parameters are affected early on by a high-fat diet in order to devise and improve protective nutritional strategies. We investigated the effect of high energy/fat intake on colon mucosa of male Wistar rats induced by a single 1,2-dimethylhydrazine (DMH) injection.

Vitamin A prevents high fat diet-induced ACF development and modifies the pattern of expression of peroxisome proliferator and retinoic acid receptor m-RNA.

Some dietary compounds, among them fats, are modulators of colon cancer risk. This study reports the modulating effects of n-6, with or without vitamin A, on promotion of colon preneoplasic lesions induced by 1,2-dimethylhydrazine (DMH) and on the expression of nuclear receptors (PPARgamma, RXRalpha, and RARbeta). One group of male Fisher rats was fed a basic diet (5% safflower oil) and two groups were fed a high-fat diet (HFD, 25% safflower oil).

Hyperlipidic diets induce early alterations of the vitamin A signalling pathway in rat colonic mucosa.

Objective: Dietary factors can be associated with colorectal cancer. Fatty acids modulate gene expression in various tissues, mediated by activation of the peroxisome proliferator activated receptor: PPAR. Vitamin A signalling is mediated by retinoic acid (RA) receptors (RAR) and retinoid X receptors (RXR).

Safety of the magnetic field generated by a neuronal magnetic stimulator: evaluation of possible mutagenic effects.

Objective: The possible mutagenicity of a magnetic stimulus was checked using the Ames test with Salmonella typhimurium TA98 and TA100 as tester strains.

Methods: Samples of these bacteria were exposed to a pulsed magnetic field, on the order of 1 T. The magnetic pulses were generated by a neuronal magnetic stimulator with a flat coil.

Effects of dairy products on heterocyclic aromatic amine-induced rat colon carcinogenesis.

Heterocyclic aromatic amines (HAA) are initiating agents of colon carcinogenesis in animals and are suspected in the aetiology of human colon cancer. In the context of prevention, it seems interesting to test possible protective compounds, such as fermented milk, against HAA food carcinogens. Male F344 rats were used in a model of HAA-induced colon carcinogenesis.

Mutagenicity and genotoxicity of sorbic acid-amine reaction products.

Sorbic acid (E200) and its salts (potassium and calcium sorbate: E202 and E203) are allowed for use as preservatives in numerous processed foods. Sorbic acid had a conjugated system of double bonds which makes it susceptible to nucleophilic attack, sometimes giving mutagenic products. Under conditions typical of food processing (50-80 degrees C), we analysed the cyclic derivatives resulting from a double addition reaction between sorbic acid and various amines.

Mutagenicity and genotoxicity of sorbic acid-amine reaction products.

Sorbic acid as well as potassium and calcium sorbate (E202 and E203) are legally used as preservatives in numerous processed foods. Owing to its system of conjugated double bonds, sorbic acid is likely to undergo a nucleophilic attack, which may turn it into mutagenic products. The cyclic derivatives resulting from a double addition reaction between sorbic acid and various amines at two different temperatures (50 degrees C and 80 degrees C) have been analysed.

Genotoxicity study of reaction products of sorbic acid.

Sorbic acid (E200) and its salts (potassium and calcium sorbate: E202 and E203) are allowed for use as preservatives in numerous processed foods. Sorbic acid has a conjugated system of double bonds which makes it susceptible to nucleophilic attack, sometimes giving mutagenic products. Under conditions typical of food processing (50-80 degrees C), we analyzed the cyclic derivatives resulting from a double addition reaction between sorbic acid and various amines.

Chemical and toxicological studies of products resulting from sorbic acid and methylamine interaction in food conditions.

Sorbic acid has a system of conjugated double bonds which makes it able to undergo nucleophilic addition reactions with certain functions. The interactions between sorbic acid and an amine present in the endogenous constituents of food were quantified. We demonstrated the formation of new products and studied the underlying mechanisms using ethyl sorbate and various amines.

Effect of resistant starch and/or fat-soluble vitamins A and E on the initiation stage of aberrant crypts in rat colon.

This study reports the modulating effects of resistant starch (RS) and the fat-soluble vitamins A or E, alone or in combination, on initiation of preneoplastic lesions in rat colon aberrant crypt foci (ACF) induced by 1,2-dimethylhy-drazine. One group of male Sprague-Dawley rats was fed a basic diet and five groups were fed experimental diets supplemented with 25% RS, 200 IU vitamin A, 5 IU vitamin E, 25% RS + 200 IU vitamin A, or 25% RS + 5 IU vitamin E for four weeks. After induction by 1,2-dimethylhydrazine, all the animals were fed basic diets for four more weeks before sacrifice.

Effects of vitamins A and E on methylazoxymethanol-induced mutagenesis in Salmonella typhimurium strain TA100.

The aim of this study is to report the antimutagenic effect of vitamin A and vitamin E towards methylazoxymethanol (MAM)-induced mutagenesis in Salmonella typhimurium strain TA100 sensitive to alkylating agents. In order to characterize different levels of action of these two fat-soluble vitamins towards the mutagenicity of MAM, several assays have been considered to show the antimutagenic effect and the possible interactions of vitamins with MAM or with the bacteria. Thus, for each vitamin, three different assays with three different incubations have been conducted: (i) MAM, bacteria and vitamins together, (ii) MAM and vitamins, (iii) bacteria and vitamins.

Vitamin A and apoptosis in colonic tumor cells.

The mechanism by which vitamin A prevents or delays chemical carcinogenesis remains unclear. In addition to these antimutagenic and antiproliferative activities, vitamin A seems able to induce programmed cell death. In this study, we assess the suggested role of vitamin A on the in vitro apoptosis induction in a rat colonic tumor cell line.

Effects of resistant starch- and vitamin A-supplemented diets on the promotion of precursor lesions of colon cancer in rats.

We have evaluated the potential protective effect of resistant starch (RS)- and vitamin A-supplemented diets on the promotion of preneoplasic lesions of rat colon, aberrant crypt foci (ACF), induced by 1,2-dimethylhydrazine dihydrochloride (DMH). We have tried to show whether the association of these two dietary constituents in the same diet could have synergistic effects. RS, vitamin A, and RS+ vitamin A were incorporated into the rat diets.

Antimutagenicity of components of dairy products.

This paper reports the potential antimutagenicity of some components of dairy products. For both milk and fermented milk, Bifidobacterium sp. Bio (strain Danone 173010), casein and calcium showed a dose-dependent antimutagenic activity against benzo[a]pyrene mutagenicity in the Ames test using Salmonella typhimurium TA98.

Lack of aberrant crypt promotion and of mutagenicity in extracts of cooked casein, a colon cancer-promoting food.

Dietary casein cooked at 180 degrees C promotes the growth of aberrant crypt foci and colon cancer in rats initiated with azoxymethane. We speculated that promotion was due to a product that could be extracted by a solvent, such as 5-hydroxymethyl-2-furaldehyde (HMF), with tumor- promoting activity or the carcinogenic heterocyclic aromatic amines (HAA). This hypothesis was tested by extracting cooked casein with solvents and water.

Effect of dairy products on initiation of precursor lesions of colon cancer in rats.

This study reports the modulating effect of some dairy products on initiation of putative preneoplasic lesions in rat colon (aberrant crypts) by 1,2-dimethylhydrazine dihydrochloride. Uninoculated skim milk, skim milk fermented with Bifidobacterium sp Bio (Danone strain 173010), and a suspension of the same lactic acid bacteria were incorporated in the animals' diet. The tested diets significantly reduced the incidence of aberrant crypts compared with the control diet by 51%, 49%, and 61%, respectively.

Inhibitory effect of dairy products on the mutagenicities of chemicals and dietary mutagens.

The antimutagenic effects of uninoculated milk and milks cultured with Bifidobacterium or Lactobacillus strains towards the mutagenicity induced by two direct mutagens, 4-nitroquinoline N-oxide and 2-nitrofluorene, and three dietary indirect mutagens, aflatoxin B1, benzo(a)pyrene and quercetin, were investigated using the in vitro Salmonella typhimurium test. Each cultured milk sample and control milk had a significant antimutagenic effect, to an extent varying with the mutagen used. Uninoculated milk had a greater inhibitory effect than cultured milks towards dietary indirect mutagens.

Effect of vitamin E dietary intake on in vitro activation of aflatoxin B1.

The molecular mechanism of action of vitamin E on mammalian cells remains to be elucidated. In this study, vitamin E dietary intake was assessed for its effects on the initiation phase of carcinogenesis. We have conducted a dose-effect relationship between vitamin E dietary intake and aflatoxin B1 (AFB1) genotoxicity measured in vitro.

Activation of benzo[a]pyrene and 2-aminoanthracene to bacteria mutagens by mussel digestive gland postmitochondrial fraction.

The ability of the mussel postmitochondrial fraction (S9) to activate benzo[a]pyrene (BaP) and 2-aminoanthracene (2AA) to mutagenic metabolites towards Salmonella typhimurium strain TA98 was tested. The mechanisms involved in this activation were investigated and mussel cytochrome P-450-dependent monooxygenases and its NADPH cytochrome c reductase were found to contribute to the activation of BaP. This activation was improved by treating the mussel with 4,5,4',5'-tetrachlorobiphenyl (TCB) (a 3-methylcholanthrene-type inducer of cytochrome P-450-dependent monooxygenase in marine fish) and was inhibited by alpha-naphthoflavone (ANF), a cytochrome P-450 inhibitor.

Effect of vitamin A dietary intake on in vitro and in vivo activation of aflatoxin B1.

The mechanism by which vitamin A prevents or delays in chemical carcinogenesis remains unclear. In the present study, we assess the suggestive role of vitamin A in the initiation phase of carcinogenesis. We have conducted a dose-effect relationship between vitamin A dietary intake and aflatoxin B1 (AFB1) genotoxicity measured both in vitro and in vivo.