• Analytical Science and Technology
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• v.23 no.6
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• pp.551-559
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• 2010

This study was conducted to establish an analytical method for the determination of seven nitrosamines in chlorinated tap water by precolumn derivatization followed by high performance liquid chromatography coupled with fluorescence detection. The derivatization procedure was optimized for denitrosation and dansylation, and then two extraction methods, liquid-liquid extraction (LLE) with dichloromethane and solid phase extraction (SPE), were compared. The SPE method employing the optimized derivation procedure showed higher extraction recovery (54.4-88.7%) and reproducibility (1.9-19.4%) than the LLE method (51.4-87.7% and 4.2-33.3%, respectively). The method detection limits were between 0.5 and 4.4 ng/L. When chlorinated water samples were collected from two treatment plants and ten household taps, and analyzed for nitrosamines, Nnitrosodimethylamine (NDMA) was the major compound found between 26.1 and 112 ng/L.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.321-329
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• 2003

In order to provide data on N-nitrosamine (NA) and sanitation in fish available in domestic markets, this study analyzed the levels of NA and its precursors in 9 samples of sea breams and yellow croakers, 12 samples of red-flesh fish, 38 samples of white fish, 5 samples of Alaska pollacks and cod, and 8 species of imported fish. Sea breams and yellow croakers had nitrite concentrations ranging from non-detectable (ND) to 7.4 mg/kg, red fish ND to 5.3 mg/kg, white fish ND to 18.7 mg/kg, Alaska pollacks 0.3 to 2.2 mg/kg, and imported fish from 0.4 to 12.8 mg/kg. Nitrates in sea breams and yellow croakers ranged from 1.2 to 41.19 mg/kg, red fish 0.6 to 26.1 mg/kg, white fish 4.3 to 75.9 mg/kg, Alaska pollacks 0.4 to 3.1 mg/kg, and imported fish ND to 16.0 mg/kg. DMA concentrations were 69.8 to 219.9 mg/l00 g in sea breams and yellow croakers, 4.1 to 336.3 mg/l00 g in red fish, 1.3 to 331.9 mg/l00 g in white fish, 15.7 to 312.3 mg/l00 g in Alaska pollacks, and 1.0 to 71.8 mg/l00 g in imported fish. TMA concentrations in sea breams and yellow croakers, red fish, white fish, Alaska pollacks and imported fish were 43.8∼496.2, 12.3∼127.0, 2.0∼525.9, 15.4∼122.4, and 4∼70.6 mg/l00 g, respectively. For NA in fish distributed in local markets, only N-nitro-sodimethylamine (NDMA) was detected, and its concentrations ranged from 4.7 to 73.7 $\mu\textrm{g}$/kg in sea breams and yellow croakers, 2.2 to 56.5 $\mu\textrm{g}$/kg in red fish, ND to 143 $\mu\textrm{g}$/kg in white fish, 3.8 to 33.3 $\mu\textrm{g}$/kg in Alaska pollacks, and 2.1 to 102.2 $\mu\textrm{g}$/kg in imported fish.

• Parasites, Hosts and Diseases
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• v.55 no.1
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• pp.21-29
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• 2017

Schistosoma haematobium is a biocarcinogen of human urinary bladder (UB). The present study investigated developing UB cancer mouse model by injecting S. haematobium eggs into the bladder wall and introduction of chemical carcinogens. Histopathological findings showed mild hyperplasia to epithelial vacuolar change, and high grade dysplasia. Squamous metaplasia was observed in the S. haematobium eggs+NDMA group at week 12 but not in other groups. Immunohistochemistry revealed significantly high expression of Ki-67 in urothelial epithelial cells of the S. haematobium eggs+BBN group at week 20. The qRT-PCR showed high expression of p53 gene in S. haematobium eggs group at week 4 and S. haematobium eggs+BBN group at week 20. E-cadherin and vimentin showed contrasting expression in S. haematobium eggs+BBN group. Such inverse expression of E-cadherin and vimentin may indicate epithelial mesenchymal transition in the UB tissue. In conclusion, S. haematobium eggs and nitrosamines may transform UB cells into squamous metaplasia and dysplasia in correlation with increased expression of Ki-67. Marked decrease in E-cadherin and increase in p53 and vimentin expressions may support the transformation. The present study introduces a promising modified animal model for UB cancer study using S. haematobium eggs.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.684-689
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• 2003

In previous paper, we isolated the bacteria, Bacillus subtilis JM-3, with proteolytic and fibrinolytic activity for candidate microorganisms that have rapid fermenting and physiological functions from anchovy sauce. This study was carried out to search physiological functions of Bacillus subtilis JM-3, such as antimicrobial, antioxidative, antimutagenic, angiotensin-converting enzyme inhibition, and anticarcinogenic activity in vitro. The cell free culture of Bacillus subtilis JM-3 showed strong antibacterial activity against Listeria monocytogenes, antioxidative activity with 87% of inhibition rate against linoleic acid, 50% of antimutagenic activity against N-nitrosodimethylamine and N-nitrosomorpholine, and 88.9% of growth inhibition rate against SNU-1 cell line (stomach cancer cell of human). However, Bacillus subtilis JM-3 did not show angiotensin-converting enzyme inhibition activity.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.19-23
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• 2003

Dimethylamine (DMA) is the immediate precursor of carcinogenic N-nitrosodimethylamine (NDMA). In vitro and in vivo experiments using whole strawberries, and garlic and kale juices were conducted to determine concentrations of DMA and trimethylamine (TMA) in foods and urine. Experimental diets [an amino-rich diet as nitrosatable precursors in combination with added nitrate-containing drinking water without (TD1) or with whole strawberries or garlic or kale juices (TD2, TD3 and TD4, respectively), or a diet of low in nitrate and amino (TD5) were incubated in simulated saliva and gastric juices at 37$^{\circ}C$ for 1 hour. We also studied the urinary excretion of DMA and TMA after consumption of the experimental diets (TD1~TD5). Urine samples were obtained for 18 hrs after consumption of experimental diets and concentrations of DMA and TMA were measured in the digested diet and urine. The DMA concentration after incubation in experimental diets (TD1~TD5) was 4.7$\pm$0.3, 6.7 $\pm$0.2, 7.9$\pm$0.2, 7.1$\pm$0.2 and 0.3$\pm$0.1 mg/kg, respectively. Urinary excretion of DMA (TD1~TD5) was 22.0$\pm$5.0, 28.3$\pm$4.3, 29.2$\pm$4.1, 27.4$\pm$4.5 and 20.4$\pm$3.1 mg/18 hr, respectively. Consumption diets with added strawberries or juices of kale or garlic increased urinary TMA and DMA, suggesting that those precursors were excreted and not converted to the carcinogen, NMDA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.4
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• pp.329-338
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• 1985

This study was undertaken in order to research formation of nitrosamine and its related compounds by salt concentration and nitrate content during Korean native soysauce fermentation. The results from measuring the changes of nitrite and dimethylamine content can be summerized as follows. As the nitrate content in used water was getting higher and the salt concentration was getting lower, the soysauce fermentation was abnormal. As the salt concentration was getting higher, the reduction of nitrate and formation of nitrite were delayed. But whether the nitrate content in used water was higher or not, the nitrite was continuously remained. An addition of ascorbic acid restrained the reduction of nitrate, and simultaneously, it could eliminate the nitrite effectively. As the nitrate content in used water, was getting higher, the content of dimethylamine was getting lower. Nitrosodimethylamine was detected from 0 to 261.34 ppb.