Sequential hepatic ultrastructural changes and apoptosis in rabbits experimentally infected with Korean strain of rabbit hemorrhagic disease virus (RHDVa) / 대한수의학회지

In this study, to understand the pathogenesis of new rabbit hemorrhagic disease virus (RHDVa) serotype, we carried out to administrate RHDVa to rabbits, and to examine sequential electron microscopic changes and relationship between pathogenesis and apoptosis. TUNEL-positive cells began to be observed from 24 hours after inoculation (HAI) and the number of positive cells was slightly increased with the course of time. Whereas marked increase of positive cells was seen in the liver from the rabbits died acutely. Typical viral particles with cup-like projections and a diameter of 30~40 nm were detected in homogenized liver samples and tissues at 36 and 48, and 48 HAI, respectively. Ultrastructurally, glycogen deposition was observed from the first stage of hepatocellular degeneration by RHDVa infection and then, swelling and disruption of cristae of mitochondria by viral particles, swelling of smooth endoplasmic reticulum, vacuoles and vesicles were detected. Condensation, margination and fragmentation of chromatin were observed in degenerative hepatocytes at 36 and 48 HAI, indicating apoptotic bodies. These data offer that hepatocytic apoptosis by RHDV infection could be closely related with mitochondrial impairment in the hepatocytes.

Sequential pathologic changes and viral distribution in rabbits experimentally infected with new Korean strain of rabbit hemorrhagic disease virus (RHDVa) / 대한수의학회지

Rabbit hemorrhagic disease is a highly acute and fatal viral disease caused by rabbit hemorrhagic disease virus (RHDV). Since first outbreak in Korea 1987, RHDV has been continually affected in the country, but the pattern of outbreak seem to be changed. In this study, to understand the pathogenesis of the new RHDVa serotype, we therefore carried out to inoculate RHDVa to rabbits, and to examine the sequential histopathologic changes and viral distribution. Macroscopically, various sized dark red or white spots or appearance were observed in the liver, lung, kidney uterus and ureter. In euhanized rabbits, significant pathologic findings such as infiltration of heterophils and mononuclear cells were observed at 24 hours after inoculation (HAI), and these were sequentially extended periportal to centrilobular area. However, in dead rabbits, severe hepatic degeneration and/or necrosis with relatively weak inflammatory responses were observed. RHDV antigens began to detect in liver, spleen, and lung from 12 HAI by PCR. Immunohistochemically, RHDV positive cells were seen in only liver from 24 HAI, and the degree of immunogen reactivity was stronger in dead rabbits than in euthanized ones. In conclusion, RHDVa caused the subacute or chronic infection accompanying low mortality and moderate to severe inflammatory reaction in rabbits, suggesting the possibility that RHD could become endemic.

A Study on the Relationship of Internet Addiction and Depression in College students / 한국역학회지

OBJECTIVES: To investigate the relationship of internet addiction and depression, and evaluate other possible related factors. METHODS: Data was based on the questionnaires from 300 college students in Seoul. Gender, age, major, family income, academic performance, people they live with, location, and main use of internet were included. We used Young`s Internet Addiction Test and Beck Depression Inventory(BDI) to measure the depression and addiction degree. RESULTS: In logistic regression analysis, it was found that gender, depression degree and main use of internet were significant variables. There were 136 males, 144 females in this study, and the risk of being addicted to internet were 10.9 times(CI:2.67~44.68) higher in male than female. People with moderate depression (Beck`s Depression Inventory(BDI) Score>20) also had higher risk(11.4 times, CI:2.03~63.95) to be addicted in internet than normal group. Lastly, in case of internet use, people who use internet for games and chatting were 6.38(CI:1.38~29.63) and 4.84 times(CI:1.30~18.06) risky compare to the group with web surfing. CONCLUSION: The result of this study suggests that there is noticeable relationship of internet addiction and depression. However we do not have evidence of exact relation between them, therefore more studies should be done.