Many epidemiologic and clinical studies have indicated that the frequency of breast cancer was lower in parous women than in nulliparous women. Moreover, the incidence of breast cancer has been reported to be lower in women with early childbirth than in women with late childbirth. To verify the effect of childbirth and the age at first childbirth on carcinogenesis and progression of breast cancer, we induced breast cancer by 7,12-dimethylbenanthracene (DMBA) in 120 female Sprague-Dawley (SD) rats, and divided them into control or experimental (DMBA-treated) nulliparous, early childbirth, and late childbirth groups to observe the incidence, latency, and size of breast cancer. Argyrophilic nucleolar organizer regions (AgNOR) count and the expression of C-erbB-2, proliferating cell nuclear antigen (PCNA), Ki-67, and minichromosome maintenance protein 2 (MCM2) in breast cancer tissues were detected by immunohistochemistry. The breast cancer incidences were 95.0%, 16.7%, and 58.8% in the experimental nulliparous, early childbirth, and late childbirth groups, respectively (all P < 0.05). Between any two of these groups, the latency was significantly different, but tumor size was similar. AgNOR count and the expression of C-erbB-2, PCNA, Ki-67, and MCM2 were significantly higher in the experimental nulliparous group than in the experimental early or late childbirth groups (P < 0.05), but no significant differences were observed between the latter two groups. Taken together, the results suggest that childbirth, especially early childbirth, can reduce the incidence and postpone the onset of DMBA-induced breast cancer.
9,10-Dimethyl-1,2-benzanthracene ; Animals ; Antigens, Nuclear ; metabolism ; Carcinogens ; Cell Transformation, Neoplastic ; Female ; Ki-67 Antigen ; metabolism ; Mammary Neoplasms, Experimental ; chemically induced ; metabolism ; pathology ; physiopathology ; Minichromosome Maintenance Complex Component 2 ; Nuclear Proteins ; metabolism ; Parity ; Pregnancy ; Proliferating Cell Nuclear Antigen ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptor, ErbB-2 ; metabolism ; Tumor Burden

OBJECTIVETo examine vibrio cholera (V.C) in aquatic products of littoral area, Zhejiang Province and to provide scientific evidence for administration of aquatic products and cholera epidemic control.

METHODSAll 990 samples of aquatic products collected from local markets, eateries and aquafarms in three chosen areas. Samples were proliferated in alkaline liquid medium, and purified in NO: 4 medium, the isolations were identified biochemically, and phenotype of strains were defined by phagocyte and coagulation with V.C. diagnostic serum. Three virulence genes (ctx, ace, zct) of the isolated strains were detected by polymerase chain reaction (PCR).

RESULTSThere were 1.41% samples caught by V.C., having a carrying rate highest in turtles of 8.9%. 14 strains were defined as three serogroups, and the numbers of Inaba, Ogawa, and Hikojima types were 2, 2, 10 respectively. Virulence genes had detected in 9 of 12 stains. All genes were detected in 5 strains, only ZOT genes in 3 strains, and both CTX and ACE genes in 1 strain.

CONCLUSIONSAquatic products from inshore in Zhejiang Province caught with V.C. strains might be divided into three serogroups. Most of them should be virulence genes. Cholera epidemic outbreak might be caused by those contaminated products.

China ; Food Microbiology ; Genes, Bacterial ; Seafood ; microbiology ; Vibrio cholerae ; genetics ; isolation & purification ; Virulence Factors ; genetics