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N Nashed

Publications and source records attributed to N Nashed.

11 recordsLinked to original sources
PubMed1981

The peritoneal cell carcinogenicity test: a new short-term test system in rats.

A new carcinogenicity test system in rats, in vivo-in vitro, is discussed in the light of the validation results obtained so far. The new test lasts only 3 weeks and it involves the use of peritoneal cells as target cells. Colony growth in soft agar is considered as a criterion for cell transformation which, in turn, is taken as evidence for a carcinogenic potential of the agent tested. There was an absence of colony growth in 98% of the cultures made from the 225 control rats tested so far. Negative results were also observed with 2 known non-carcinogens, whereas positive cultures were observed for 7 known carcinogens belonging to 5 different classes. These results suggest that the chosen target cells are sensitive enough to detect the carcinogenic effect of agents applied in vivo even if these are strictly organotropic in their action. Several interesting areas of future research are discussed.

Animals↗
PubMed1980

An in vivo-in vitro short term carcinogenicity test using rat peritoneal cells.

A new short-term mammalian carcinogenicity test system is presented in which an in vivo application in rats is followed after 2 weeks by an in vitro culture of the peritoneal cells. One week of culture was sufficient to induce colony growth in soft agar in some cultures of the dimethylnitrosamine (DMNA)-treated, but not in those of control, rats. The results proved to be reproducible and dose-related. Suspended colony growth was not observed in cultures of control rats stimulated successively by the 2 mitogens: thioglycollate and Al(OH)3. The incidence of rats showing transformed colonies in their cultures after a single DMNA dose of 20 mg/kg was nearly double that reported for rats developing tumors after a higher single dose of 30 mg/kg DMNA. More recent experiments have shown that whereas the carcinogen benzo[a]pyrene was positive, its non-carcinogenic analog benzo[e]pyrene was negative; both applied at a single oral dose of 15 mg/kg. A similar result was observed with the acetylaminofluorene (AAF) analogs: 2-AAF and 4-AAF, where the former, a carcinogen, proved positive and the latter, a non-carcinogen, negative. Both analogs were applied at a single oral dose of 50 mg/kg. 2-AAF was also positive at a dose of 25 mg/kg corresponding to 2.5% of the highest tolerable dose of this carcinogen. These results suggest a high structure-related specificity of our test system. Many more similar tests with carcinogen/non-carcinogen analogs will be needed however, before this specificity can be sufficiently established.

2-Acetylaminofluorene↗
PubMed1976

Evaluation of a possible role for antimutagens, antiteratogens, and anticarcinogens in reducing environmental health hazards.

The use of protective agents (e.g., sulfhydryl compounds, certain vitamins, amino acids, cations, and antibiotics) offers a novel and promising means of dealing with the ever increasing burden of environmental hazards facing man. Through the daily uptake of minimal doses as a prophylactic measure by the most endangered groups of the population or by direct mixing of the appropriate protective agent with the inducer (e.g., pesticides or anticancer drugs) it should be possible to reduce or prevent some of the most serious toxic side effects including those of a mutagenic, teratogenic or carcinogenic nature. Among some of the most outstanding protection examples cited are the antimutagenic, antiteratogenic and anticarcinogenic effects of L-cystein, and of some of the vitamins. However, in view of our limited understanding of protection mechanisms in this fairly new field of research and due to the toxic side effects of some of the protection agents themselves, a large-scale application of this approach cannot be recommended as yet. More research is urgently needed to study protection mechanisms in suitable standardized model systems and to develop safer and more efficient protective agents.

Amino Acids↗
PubMed1975

A technic for the collection of peritoneal cells from laboratory animals.

A simple method was devised for the collection of peritoneal cells from rats, Chinese hamsters, and mice using a special glass pipette. Cell collection was performed by lavage on the intact unanesthetized animal within 30-60 sec, and it yielded 5-20 million cells per rat and 0.3-2.5 million cells per mouse or Chinese hamster. The procedure can be repeated on different occasions in the same animal without apparent adverse effects.

Animals↗