• 생명과학회지
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• 제19권10호
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• pp.1451-1455
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• 2009

Porcine cytomegalovirus (PCMV) is a betaherpesvirus which causes reproductive failure in breeding sows and generalized infection in newborn piglets. It has worldwide distribution including Korea. Serological survey on this virus has been reported in 76.3% of pigs, but virological survey and epidemiological analysis on PCMV distribution have been reported in only a few papers in Korea. In this study, we investigated the virological prevalence and infection status of PCMV on a farm level in selected swine farms with respiratory diseases. A total of 1,938 blood samples taken from groups of pigs of different ages were collected from 31 farms distributed nationwide in 2006 and 2007 and tested by PCR to detect the presence of PCMV. Virological prevalence at farm level and pig level were 96.8% and 17.5%, respectively, suggesting that PCMV has endemically infected Korean pig herds. The prevalence at farm level in gilts, sows and suckling piglet groups were 16.7%, 36.7% and 56.7%, indicating that vertical infections frequently occurred in conception or newborn stage. Thereafter, detection rates of PCMV were slightly increased in pig groups aged 40 and 70 days (70.0% and 73.3%), and then gradually decreased as they aged - 33.3% in 100, 26.7% in 130 and 16.7% in 160 day old pig groups. The prevalence at pig level has similar patterns to that at farm level. With the passage of time, the variation of infection patterns of PCMV was investigated in four PCMV-positive farms. Three blood samples were collected at intervals of 6 months in each farm, and examined for presence of PCMV using PCR. The results revealed that once PCMV was introduced to the pig farms, it continuously circulated between and within groups of sows and piglets in those farms. Taken together, it can be concluded that PCMV has endemically infected Korean pig farms and has the potential risk for emerging pathogen in combination with the known endemic pathogens including porcine reproductive, respiratory syndrome virus and porcine circovirus type 2. Therefore, more research is needed on diagnosis, epidemiology and control strategy for PCMV on the field.

• 대한바이러스학회지
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• 제26권1호
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• pp.67-76
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• 1996

The methods that make Hantavirus grow consist of inoculation into the experimental animals and cultured cells. The cultured cells, such as Vero-E6 and A549 cells, have been usually used for isolation of the virus and the animals, such as mice and rats, are used for large scale preparation of the virus so far. Furthermore, the cell can be used to maintain the virus and assay the infectivity and the animals can be used for the experiment of viral pathogenicity and challenge for assessment of vaccine. Apodemus mice, the own natural host of the virus, has been used for challenge test of Hantaan virus. However it has been pointed out to difficult handling and breeding the animal in laboratory. Therefore, we attempted to establish a new animal model for challenge test at the time of isolation of Maaji virus which is a new hantavirus similar but distinct to Hantaan virus. In suckling hamster, the titer of Maaji virus and the lethality to mice of the virus were increased gradually in the titer and lethality through passage by intracerebral (IC) inoculation. We tried to re-adapt this brain virus to lung of weanling hamster. The brain passaged virus was inoculated into weanling hamster intramuscularly. Again, the titer of the virus in lung was also increased by continuous passage of this virus. This facts could regarded as adaptation to new environment in which the virus proliferates. To identity the virus passaged in hamster with Maaji virus, both of the virus passaged in hamster brain and lung were compared with Maaji virus (MAA-I) and Hantaan virus (HTN 76-118) by means of restriction fragment length polymorphism (RFLP) and slingle strand conformation polymophism (SSCP). As a result, we conclude that Maaji virus could be adapted successfully to weanling hamster through this passage strategy. Utilizing this adapted Maaji virus strain, hamster model is able to be used for challenge test in hantaviral vaccinology and further experiments utilizing hamster system as a rather available and convenient lab animal are expected.

• 대한수의학회지
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• 제34권4호
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• pp.787-799
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• 1994

To elucidate morphologic lesion of porcine exudative epidermitis which is occurred sporadically in Korea, Staphylococcus hyicus subsp. hyicus isolated from the naturally affected pigs was inoculated to suckling pigs. The infected piglets were observed grossly and histopathologically. Although affected piglets were taking acute, subacute, or chronic course, some piglets suffered from chronic disease showed poor prognosis and marked growth depression. Affected peglets had erythematous skin on the face, ear, and abdomen and these localized lesions appear as brownish spots of exudative epidermitis and fromed crust in the early stage. But, after this stage, the skin were covered by viscous greasy exudate and formed blackish brown crust and appeared fissures and hypertrophy. Grossly, there has been hemorrhage with the removal of crust-like materials of epidermis and edematous subcutis. The superficial lymph nodes were edematous and swollen or congested and hemorrhagic. Some piglets had swollen ureters, cysts in the renal cortex, or polyarthritis. A few cases had mild edematous swelling of kidney, intestinal catarrh and congestion of brain. Microscopically, skin lesions had detachment of keralinized layer and parakeratosis of epidermis, hydropic degeneration of epidermal cell, and retrogressive degeneration of hair root sheath. Dermis had edema, and infiltration of neutrophils and mononuclear cells. As the disease was proceeded, there was marked perivasculitis with lots of mononuclear inflammatory cells. More chronic lesions formed granuloma-like bodies(nodules) due to more mononuclear, perivascular inflammatory cell infiltration and proliferation of fibroblast. Lots of plasma cells and eosinophils were also present in dermis. Epidermis was hyperplastic by proliferation of basal cells stratum germinativum and epidermal pegs often extended into the dermis. In secondary infection, lots of neutrophils could be seen in epidermis and derms. Kidney had neutrophilic infiltration, necrotic and cystic glomeruli, and dilation of renal tubules and ureters. Purulent arthritis was sometimes observed in joints. Three days old mice administrated Staphylococcus hyicus subsp hyicus subcutaneously before had focal congestion and hemorrhage, necrosis, and subcutaneous edema of the skin. This observation was also seen in the study of mice administrated exfoliatin toxin of Staphylococcus which evoked human staphylococcal scalded skin syndrome.

• Asian-Australasian Journal of Animal Sciences
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• 제16권9호
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• pp.1239-1241
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• 2003

Korean cattle breeders have shown interest in genetic improvement of milking ability because poor milking ability and short suckling period of Korean cattle is a hindrance to growth of calves. In this study, daily milk yields by period in Korean cattle were analyzed with an animal model. The milk yields were actually measured at sequential intervals from 1 to 4 months after calving: daily milk yields from delivery to 1 month (DMY1), from 1 to 2 months (DMY2), from 2 to 3 months (DMY3), and from 3 to 4 months (DMY4). Genetic variance estimates gradually increased by the periods while environmental variance estimates gradually decreased. This resulted in a dramatic increase in the heritability by periods: 0.02 for DMY1, 0.11 for DMY2, 0.16 for DMY3, and 0.42 for DMY4. In multi-trait analyses with daily milk yield and body weight of calf, genetic correlation estimates between milk yield and body weight were quite small (-0.08 to 0.02 for birth weight and -0.10 to 0.00 for weaning weight). The trends of the heritability estimated in this study showed that the genetic effects were more influential when the milking period was longer, suggesting genetic evaluations with daily milk yield collected at a longer period.

• Asian-Australasian Journal of Animal Sciences
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• 제27권10호
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• pp.1452-1460
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• 2014

The objective of this work was to evaluate the nutritional parameters of young bulls supplemented with different ratios of protein: carbohydrate on tropical pastures from 4 until 18 months old. Fifty-five non-castrated beef calves ($138.3{\pm}3.4kg$, 90 to 150 d of age) were used. The calves (young bulls) were subjected to a 430-d experimental period encompassing 4 seasons. The treatments were as follows: control, only mineral mixture; HPHC, high protein and high carbohydrate supplement; HPLC, high protein and low carbohydrate supplement; LPHC, low protein and high carbohydrate supplement; and LPLC, low protein and low carbohydrate supplement. The amount of supplement was adjusted every 28 d. Dry matter (DM) intake was higher in the dry-to-rainy transition and rainy seasons for all nutritional plans. Non-supplemented animals had lower intakes of DM and total digestible nutrients (TDN) than supplemented young bulls in all seasons. Although differences in DM intake were not observed between supplemented animals, the supplements with high carbohydrate (HPHC and LPHC) had lower forage intake during suckling (rainy-to-dry transition season) and in the rainy season. However, the HPHC treatment animals had higher intake and digestibility of neutral detergent fiber. It can be concluded that supplementation with high protein levels (supplying 50% of the crude protein requirement) provide the best nutritional parameters for grazing young bulls in most seasons, increasing intake and digestibility of diet, and these effects are more intense when associated with high carbohydrate levels level (supplying 30% TDN requirement).

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1585-1591
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• 2008

The aim of the present work was to monitor metabolic and hormonal profiles in newborn kids, born from dams fed diets with low or high levels of energy requirements. Starting from the last month of pregnancy, 14 goats were randomly allocated to two groups: Group LD (low diet) and Group HD (high diet) that received a diet that covered 80% and 140% of their energy requirement, respectively. At delivery, the kids were weighed and a blood sample was taken before they suckled colostrum (Time 0) and 1, 2, 3, 12 and 24 h after they started suckling. Plasma insulin, IGF-I, glucose, fT3 and fT4 concentrations were not influenced by the dietary treatments, but a significant effect of time was observed as they progressively increased during the first 12 h of life. Plasma cholesterol, triglyceride, albumin, globulin and total protein plasma concentrations were significantly higher in Group HD than those of Group LD. In Group HD, cortisol concentrations were significantly lower than those of Group LD. Positive correlations were observed between LW and IGF-I (r = 0.71; p<0.05), plasma insulin and glucose (r = 0.79; p<0.05) and total protein and globulin concentrations (r = 0.97; p<0.001). Our results show that perinatal nutrition affects newborn goat kids' metabolic and hormonal profile.

• Applied Microscopy
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• 제27권2호
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• pp.177-187
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• 1997

Hydrocephalus is induced experimentally in prenatal and suckling animals following an injection of 6-aminonicotinamide (6-AN). The most remarkable characteristic of these animals is aqueduct stenosis caused by swellings of the ependymal cells and subependymal cells in the periaqueductal gray matter and the central canal of the spinal cord. The present study was undertaken to investigate the morphological changes of the ependymal cells in the central canal of the spinal cord of 3.5 months old hamster after treatment with 6-AN. Intraperitoneal administrations of 6-AN (10 mg/kg body weight) every two days gave rise to partial central canal stenosis of the spinal cord after 27-29 days (13-l4th injection), but cilia and microvilli were located in the strictural area of the con#rat canal. The vacuolations in the ependymal cells were not observed and degenerating changes of intracellular organelles of the ependymal cells did not occur, so that the ependymal cells lining the central canal of the hamster spinal cord were not affected by 6-AN. But the present study demonstrate that 6-AN causes to create numerous vacuoles in the subependymal area of the central canal. Although the vacuoles were well developed in the neuroglial cells and the neuropils of the subependymal area, the neurons were not affected by 6-AN. These results strongly suggests that partial central canal stenosis occurred by 6-AN was due to vacuolations and swellings of the neuroglial cells and nueropils in the subependymal area.

• 대한수의학회지
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• 제30권4호
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• pp.515-523
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• 1990

Plasma progesterone concentrations in 44 suckling Korean native cows were determined to monitor ovarian activity postpartum by radioimmunoassay. Blood samples were collected in 3 day intervals from 15 to 80 days postpartum. The ovaries and uterus were examined in 6 day intervals by rectal palpation. Results are summaried as follows: 1. The cows were qualified into four categories; Type I(normal): cyclic changes in plasma progesterone concentrations appear within 45 days postpartum(35 cows, 79.5%), Type II(cycle delayed): delayed resumption of ovarian activity by 55 days postpartum(5 cows, 11. 4%), Type III(cycle ceased with low progesterone): plasma progesterone concentrations remained low(${\leq}1ng/ml$) until 80 days postpartum(3 cows, 6.8%), Type IV(cycle ceased with high progesterone): plasma progesterone concentrations after 30 days remained high(${\geq}4.0ng/ml$) until 80 days postpartum(1 cow, 2.3%). 2. Out of the cows classified Type II and III, 7 cows had inactive ovaries and a cow had follicular cyst by rectal palpation. The cow of Type IV was diagnosed as bearing persistent corpus luteum by rectal palpation. 3. About 82% of the cows showed significant rises in plasma progesterone concentrations prior to 50 days postpartum and the cows of Type II and III resumed cycles in 31. 6(range 17~55) days after calving. However, 43.2% resumed cycles in 50 days postpartum by estrus signs. These results indicated that plasma progesterone concentrations assessed by radioimmunoassay can be utilized for monitoring postpartum ovarian activity and would be helpful for the early detection of ovarian dysfunction in the Korean native cow.

• 대한수의학회지
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• 제40권1호
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• pp.42-48
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• 2000

Akabane disease is transmitted through mosquitoes in cattle, sheep and goats. It shows congenital abnormalities including encephalomyetitis, hydranencephaly, neurogenic arthrogryposis, and deformed neonatal calves. Akabane viruses, 93FMX and K-9 strain, were isolated from fetal matrix of aborted cow and blood of healthy cow, respectively. S gene sequences of 93FMX and K-9 showed 100% homology with that of OBE-1 strain isolated in Japan. Based upon our sequencing data, we synthesized specific primers for PCR diagnosis. Using these primers, we were able to amplify the S gene of Akabane virus not only from the culture fluid of Vero cells but also from the brain tissue of suckling mouse inoculated with, Akabane virus. These PCR products were confirmed by Southern blot hybridization. Not only the sensitivity of PCR test was high enough to detect the viruses of $10^{1.0}TCID_{50}/ml$, but also the time for diagnosis was significantly shorter than that of the virus isolation by tissue culture method. This method was also effective for the detection of Akabane virus in the cerebrum of fetus. RT-PCR method may be used for a useful diagnostic test of the clinical cases of Akabane disease.

• 대한미생물학회지
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• 제19권1호
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• pp.65-71
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• 1984

The author attempted serological typing with the slide agglutination and the production of heat-labile enterotoxin (LT) and heat-stable enterotoxin (ST) by the enterotoxingenic eschenchia coli 446 strains isolated from diarrheal patients. The enterotoxingenic E.coli, producing LT and/or St, were detected by use of assays in the reversed passive hemagglutination(RPHA) and the suckling mouse method. The results obstained were as follows: 1. Of 446 strains isolated, 88 strains(19.73%) produced LT, while 224 strains(50.22%) produced ST, 134(30.05%) produced both LT-ST simultaneously. Serological typing were typed into 06, 08, 020, 025, 027, 0126, 0148 and 0159. Serotype 06 had the highest incidence of 26.46% followed by 0148(18.16%), 027(14.57%); 025(10.99%), 0159(4.03%), 0126(3.59%), 020(1.12%) and 08(0.45%). 2. Serotype 06, 08 and 025 almost always produced both LT and ST, whereas serotypes 020, 027 and 0148 almost always produced only ST. And serotypes 06, 025, 0126 and 0159 almost always produced LT or ST. 3. Of 134 LT-ST positive strains, 115 strains were serotype 06, 3 strains were 025, 2 strains were 08, and 14 strains were 0 untypable. 4. Of 224 ST positive strains, 65 strains were serotype 027, 81 strains were 0148, 16 strains were 0159, and 42 strains were 0 untypable. 5. Of 88 LT positive strains, 45 strains were serotype 025, 5 strains were 0126, 2 strains were 0159, and 42 strains were 0 untypable.