• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.223-231
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• 1976

Dimethylamine(DMA) is known as an origin compound of dimethylnitrosamine which is responsible for carcinogenesis. It has been also reported that relatively large amount of DMA is distributed in fish muscle, particularly in salted and fermented fish. Tn this experiment, the degradation products of protein and trimethylaminoxide(TMAO) by the temperature conditions of $17^{\circ}C\;and\;27^{\circ}C$ in the course of anchovy fermentation with $22\%$ of salt were analysed, and the formation of DMA was discussed. Protein-N decreased through the whole fermentation period ill the conditions of $17^{\circ}C\;and\;27^{\circ}C$ whereas amino-N increased proportionally to the decrease of protein-N, and the increasing rate of amino-N was remarkably faster at $27^{\circ}C$ than at $17^{\circ}C$. Trimethylamine(TMA) gradually increased with the decrease of TMAO till 69th day of fermentation, hereafter tended to slightly decrease. It seemed that the difference in fermentation temperature affects on the formation of DMA and obviously on the variation of TMAO. Both DMA and TMA content were inversely varied with the TMAO content. Correlation coefficient of DMA to TMAO in quantitative variation was shown -0.811 at $17^{\circ}C$ and -0.865 at $27^{\circ}C$ of fermentation temperature respectively. The results suggested that the formation of DMA during fermentation of anchovy was attributed to the degradation of TMAO showing, contributorial ratio of 0.66 at $17^{\circ}C$ and 0.75 at $27^{\circ}C$ respectively.

• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.151-159
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• 1996

This study was carried out to evaluate the effects of all-trans retinoic acid(RA) on the development of cholangiocarcinoma in hamsters. Eighty six female Syrian golden hamsters were divided into four groups. Group I was for the induction of the cholangiocarcinoma, which was infected orally with C sinensis and given dimethylnitrosamine(DMN, 15ppm) in drinking water for 4 weeks. Group II was for evaluating the effect of all-trans RA treatment on the cholangiocarcinogenesis, which was treated the same as group I and orally given RA(1mg/kg, 5 times per week) for 15 weeks. Group III was given only RA hr 15 weeks. Control group IV was given only soybean oil which was solvent for RA treatment. More than 5 heads of hamsters in each group were sacrificed at 4, 7, 11 and 15 weeks after the begining of the experiment. The livers were examined grossly, histopathologically, and immunohistochemically. The results obtained were as follows : 1. Death of animals started from the 11 weeks after the begining of the experiment. One of the total 22 animals(5%) and 7 of the total 24 animals(29%) died in group I and group II, respectively. 2. Proliferation of oval cell was peaked at 11 weeks in group I and at 7 weeks in group II, and decreased gradually after those periods of the time. 3. Cholangiocarcinomas were found in 1 of 6 animals(17%) at 11 weeks and in 4 of 6 animals(67%) at 15 weeks in group I, respectively. But in group II, the cholangiocarcinomas occured in 1 of 5 animals(20%) at 7 weeks, in 7 of 12 animals(58%) at 11 weeks and in 2 of the rest animals(100%) at 15 weeks, respectively. 4. Expression of $\alpha$-fetoprotein(AFP) of the oval cells in the group II showed the same degree of positive reaction at that of group I at 4 weeks. But AFP postive oval cells decreased gradually and AFP negative oval cells(ductlike oval cells) increased gradually. 5. Expression of cytokeratin of the oval cells in group II was shown slightly at 4 weeks and the degree of expression increased moderately from the 7 weeks. But the expression of the oval cells in group I was shown slightly after the 7 weeks. These results suggested that all-trans RA promoted the occurrence and the rate of cholangiocarcinoma by inducing differentiation of small cells and oval cells in the liver of hamsters infected with C sinensis and treated with DMN.

• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.147-152
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• 1979

Nitrite, one of the precursors of dimethylnitrosamine, distributes widely in natural foods and is also used as a color fixing agent in meat products. This experiment was carried out to determine the contents of nitrite and nitrate of Korean foods and suman saliva. Nitrite content was measured by use of the diazotization-coupling reaction, while cadmium reduction method by use of metallic cadmium was applied to determine nitrate. The objects are about 150 of female students who are $19{\sim}22$ years old ands standard analytical values of nitrate contents of $10{\sim}20$ samples produced in various places. The results showed that contents of nitrite and nitrate of Korean foods and saliva were relatively high levels.