Biomedical subjects

A Nyska

Publications and source records attributed to A Nyska.

166 records · Page 10Linked to original sources

PubMedDate not supplied

Inhibitory effect of lycopene on cataract development in galactosemic rats.

This study investigated the effect of antioxidants on cataract formation in galactosemic rats. Two antioxicants were compared: lycopene, a carotenoid derived from tomato, and butylated hydroxytoluene (BHT), a known antioxidant substance. The control group was fed with galactose 30%. The experimental groups received, in addition to galactose 30%, either lycopene 0.8% or BHT 0.2%. Cataractogenesis was evaluated by the incidence of cataract, grading of cataract, histology of the lenses, aldose reductase (AR) activity, protein levels, and reduced glutathione (GSH) contents in the lens. In both experiemtal groups: 1) the incidence and grading of cataract were lower, 2) the protein levels and GSH content were higher, and 3) the AR was decreased compared to the control group. In conclusion, "natural antioxidants" such as lycopene derived from tomato have a similar effect as BHT in delaying cataractogenesis in rats.

Aldehyde Reductase↗

PubMedDate not supplied

Tumor-promoting and tumor-protective effects of high-fat diets on chemically induced mammary cancer in rats.

We studied the effects of different dietary fats on experimental rat mammary lumorigenesis induced by 9,10-dimethyl-1, 2-benzanthracene (DMBA). Rats were randomly placed into four groups fed different diets: a chow diet, and high-fat (15%) diets derived from avocado, soybean or olive oils. The rats were killed 12 weeks after treatment with DMBA (a single dvse of 10 mg/rat) and maintenance on these diets. The olive diet was associated with a significant reduction in the tumorigenic effect of DMBA: tumor incidence decreased to 30%, as compared to 44%-55% in the other dietary groups studied (p < 0.05). The protective antitumor effect of the olive diet was found to be connected to its dietary content of monounsaturated fatty acids such as oleic and palmitic acids and with serum concentrations of stearic acid. The promotive tumorigenic effects of the other high-fat diets were associated with their high levels of some polyunsaturated fatty acids (linoleic and alinolenic). Malignant mammary tissue exhibited higher values than benign tissue for all the argyrophilic-nucleolar-organizer region parameters measured. The tumor-associated protein p53 was accumulated to high levels in the blood of tumor-bearing rats, but not in that of the non tumor-bearing rats.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Role of apoptosis, proliferating cell nuclear antigen and p53 protein in chemically induced colon cancer in rats fed corncob fiber treated with the fungus Pleurotus ostreatus.

The role of apoptosis, proliferative cell nuclear antigen (PCNA) and p53 protein in the preventive effects of dietary fiber treated with the fungus Pleurotus ostreatus on rat-colon tumorigenesis was studied. Tumors were induced by five subcutaneous injections of 1,2-dimethylhydrazine (DMH), 20 mg/kg rat, once a week. Rats were fed a semi-synthetic fiberfree diet (control) or a high-fiber diet (15%) derived from corncob treated or non-treated with the fungus. The rats we sacrificed 24 weeks after the first carcinogenic injection. The fungus treated corn-cob significantly decreased tumor incidence (to 26%) as compared to 44% and 57% in the other dietary groups. The apoptotic index (AI) significantly decreased in malignant tissue as compared to non-tumorous tissue. PCNA and cytoplasmic content of p53 protein exhibited an increasing trend in malignant tissue as compared to benign tissue (at 15% and 18%, respectively). The fungus-treated corncob significantly increased the content of p53 in the cell cytoplasm (to 33%) and its serum levels in tumor-bearing rats (to 38%). The cellular concentration of PCNA decreased to 61% in tumors obtained from rats fed the fungus-treated corncob as compared to controls. A high positive correlation was found between tumor grade and p53 protein in the serum (r = 0.97) or in the cell cytoplasm (r = 0.77) and between tumor grade and PCNA (r = 0.81). An inverse relationship was found between tumor grade and AI (r = -0.63). We found that 15% of corncob fiber alone seems not to be enough to prevent chemically induced tumorigenesis. The corncob fiber (15%) treated with the fungus had a significant protective effect against DMH-induced rat colon cancer, even at 15% and this effect was accompanied by the activation of some cellular mechanisms such as apoptosis, PCNA and p53 protein activation. Incubation of corncob with the fungus Pleurotus os, increased the dietary fiber content up to 78%. Thus corncob inhibits colon cancer development, and, therefore, may considered of potential use to the public.

1,2-Dimethylhydrazine↗

PubMedDate not supplied

Role of apoptosis, proliferating cell nuclear antigen and p53 protein in the immune response of rat colon cells to cancer and vaccination with anti-p53 polyclonal antibodies.

BACKGROUND: Previously it was shown that rabbit anti-p53 antibodies can exert tumor-suppressive effects on chemically induced rat colon cancer (Cancer J, 10:116-120, 1997). This work examines the role of some components of the immune system in the response of the rat colon cells to treatment with a carcinogen and anti-p53 antibodies. METHODS: The following groups of rats were studied: a) control non treated rats; b) tumor-free non vaccinated rats treated with a carcinogen; c) tumor-bearing non vaccinated rats; d) tumor-free vaccinated rats exposed to a carcinogen; e) tumor-bearing vaccinated rats. The manifestation of apoptosis, proliferating cell nuclear antigen (PCNA), mitotic index, T lymphocytes and p53 protein was compared between the different groups of rats. RESULTS: The apoptotic index and the number of p53-positive cells and T lymphocytes were significantly higher in colon adenocarcinomas obtained from vaccinated rats than in unvaccinated rats. PCNA was lower in tumors from the vaccinated rats, whereas the proliferating cell index was not different between the both groups of rats. An inverse relationship was seen between apoptosis and most other parameters studied. The inverse correlation found between apoptosis and p53 protein in this study demonstrated that apoptosis acts as a p53-independent parameter in chemically induced rat colon cancer. CONCLUSIONS: Our findings demonstrated that vaccination significantly activated apoptosis in both types of colon tissue, and induced synthesis of p53 protein in tumor tissue. Vaccination with anti-p53 polyclonal antibodies seemed to activate the immune system and to stimulate some of its cellular components responsible for tumor suppression.

Adenocarcinoma↗