ABSTRACT
Gastric cancer(GC), one of the most common malignancies worldwide, seriously threatens human health due to its high morbidity and mortality. Precancerous lesion of gastric cancer(PLGC) is a critical stage for preventing the occurrence of gastric cancer, and PLGC therapy has frequently been investigated in clinical research. Exploring the proper animal modeling methods is necessary since animal experiment acts as the main avenue of the research on GC treatment. At present, N-methyl-N'-nitro-N-nitroso-guanidine(MNNG) serves as a common chemical inducer for the rat model of GC and PLGC. In this study, MNNG-based methods for modeling PLGC rats in related papers were summarized, and the applications and effects of these methods were demonstrated by examples. Additionally, the advantages, disadvantages, and precautions of various modeling methods were briefly reviewed, and the experience of this research group in exploring modeling methods was shared. This study is expected to provide a reference for the establishment of MNNG-induced PLGC animal model, and a model support for the following studies on PLGC.
Subject(s)
Animals , Rats , Gastric Mucosa , Methylnitronitrosoguanidine/toxicity , Precancerous Conditions/chemically induced , Stomach Neoplasms/drug therapyABSTRACT
Two cadmium resistant mutants (Cd1 and Cd2) of Aspergillus niger, among the six isolated by mutagenization with N-methyl N'-nitro-N-nitrosoguanidine (MNNG) at pH 6.4 were selected for the study. Analysis of lipid composition of the mutants and the wildtype indicated that total lipid as well as individual lipids of the cadmium resistant mutants were changed as compared with that of the wildtype. The increased activities of metal-lothionein and reduced activities of D-xylose isomerase and L-phenylalanine ammonia lyase in cell free extract of the cadmium resistant mutants suggested that mutants could allow high concentration of cadmium salt as compared with that of the wildtype. The respiratory activity and intracellular as well as extracellular Cd2+ concentration of the mutants reflected the high tolerance of the Cd mutants to cadmium ion.
Subject(s)
Aldose-Ketose Isomerases/analysis , Aspergillus niger/chemistry , Cadmium/analysis , DNA Mutational Analysis , Drug Resistance, Fungal/genetics , Lipids/chemistry , Metallothionein/analysis , Methylnitronitrosoguanidine/toxicity , Mutagenesis/genetics , Mycelium/chemistry , Oxygen Consumption/genetics , Phenylalanine Ammonia-Lyase/analysis , Survival AnalysisABSTRACT
Using Salmonella typhimurium strains TA 100 and TA 1535, the mutagenicity and anti-mutagenicity of extracts of several spices were checked. Spices like pepper, pippali, ginger and mustard increased the number of revertants indicating their mutagenic potential. Garlic extract on the other hand was found to inhibit the mutagenicity produced by direct acting mutagens such as N-methyl N'-nitro-N-nitrosoguanidine and sodium azide. Asafoetida and turmetic extract were found to inhibit microsomal activation dependent mutagenicity of 2-acetamidofluorene. Similar results were also obtained using curcumin and eugenol which are phenolics present in turmeric and clove respectively. These results indicated that some of the spices may ameliorate the effect of environmental mutagens especially present in the food.