Swine plasminogen is not activated by staphylokinase of Staphylococcus aureus. In this study, the activation of swine plasminogen by staphylokinase of Staph hyicus subsp. hyicus was investigated and the effect of EDTA(disodium) on plasminogen activation was also studied. When the activation of swine plasminogen by staphylokinase of Staph hyicus subsp. hyicus was examined in fresh swine plasma, swine plasminogen could be weakly activated. However, when EDTA was added to the swine plasma, plasminogen activation was markedly enhanced, but this enhancement was not observed on bovine fibrin-dog plasminogen agar plate containing EDTA. Chicken and bovine plasminogens were not activated by staphylokinase of Staph hyicus subsp. hyicus. Using fresh swine plasma agar containing 0.07% EDTA, staphylokinase activity was detected in 96.3% of Staph hyicus subsp. hyicus strains isolated from pigs and in none of the chicken and bovine strains.

We analyzed the conentes of 12 types of minerals such as calcium in muscle from various species. Thereafter we ovserved changes of the concetrations according to age, part and sex in major domestic animals. The concentraions of calcium, iron, sodium, potassium, magnesium and zinc were high respectively whilst the content of cobalt, chromium, copper, manganese, molybdenum and nickel were low respectively in the muscle. The concentration of calcium was high in duck and dog but low in pig and horse. Also high level of sodium content was detected in dog and the content of potassium, iron showed high level in horse compared with the content in other animals. In 6 types of microminerals as cobalt, the level of muscle wer no more than 1 ppm showing very low content in all animal, but 2.99+_0.85ppm of copper in duck was an exceptional case. According to the age some species showed small range of variation centering on macrominerals and there was no remarkable change in microminerals. Distribution of minerals was different according to the part and the variation was very diverse compared with other factors such as age and sex. Additionally, the content of mnerals in muscle was higher in female than in male chicken and duck. In conclusion, the difference of the content of minerals according to the species was mainly focused on macrominerals.

From July of 1997 to June of 1998, total 279 raw milk samples over wkthdarwal period after mastitis treatment from dairy farms located in the provinces of Kyonggi and Choongchung were collected to test drug residues. Each sample was tested by TTC-II test and Delvotest SP. Among the total 152 raw milk samples of cow treated by beta-lactams, 32 samples(21.2%) were positive on the Delvotest and 15 samples(9.9%) showed positive on the TTC-II test. Also, from the total 37 samples treated by sulfonamides, 5 samples(13.5%) were positive on the Delvotest and 3 samples(8.1%) showed positive on the TTC-II test. For the total 55 raw milk samples of cow treated by tetracyclines, 9 samples(16.4%) were positive on the Delvotest and 5 samples(9.1%) showed positive on the TTC-II test. In addition, from the total 35 samples treated by aminoglycosides, 7 samples(20.0%) were positive on the Delvotest and 5 samples(14.3%) showed positive on the TTC-II test. Our study shows that it is possible that drugs are to be detected by the drug residues test of and individual raw milk even over the withdrawal period after mastitis treatment and the raw milk of bulk tank.

A nation wide sero-epidemiological survery of porcine reproductive and respiratory syndrome(PRRS) was carried out to analyze the current status of the PRRS virus infections in the field using the indirectr immunofluorescent antibody assay(IFA) with the field isolate PL96-1. Since the first report of the antibody detection to PRRSV in 1993, the prevalence of seropositive pigs has increased dramatically and the data indicate that over 21% of the pigs and around 60% of the farms showed seropositives to the PRRS virus. A slightly higher positive rate was recognized in breeders than fattenings and it might be due to the higher age at the time of testings. No significant regionl defferences were detected in the sero-epidemiological survey. Higher sero-positive rate in growers indicatesthat PRRSV infection in the field was common after weaning(around 40 days). However, the number of seropositive pigs were declined in fattening pigs. Sows showed around 26% of sero-positive rate that there is a higher chance of continuous virus circulation in the infected farms. Low rate of sero-positivity in boars(9.8%) implies that there is high demand in proper controlmeasures to prevent virus spreading through breeding procedures such as natural or artificial insemination Therefore it was concluded that PRRSV infection in domestic swine herds is endemic and the positive rate and economic loses will be increased by spontaeous infections in naive farms.

There have been a number of studies of gonadotropes secretin LH and FSH in the adenohypophysis, but the pattern of hormone storage and secretion of these cells still remains a controversial matter. In this study, we examined whether gonadotropes contained both of LH and FSH, and if so, how these hormones were distributed within the secretory granules. Hypophyseal sections of Korean native goat were simultaneously immunostained for LH and FSH antisera by protein A-gold technique. It was found that most gonadotropes contained both FSH and LH, but hormone storages in the secretory granules were some different among cells. Three types of gonadotropes were identified by the shape and size of the secretory granules and their hormone storage patterns. One type(I) of gonadotropes contained oval secretory granules, which immunoreactivity for FSH and LH were very weak. The size of secretory granules ranged from 160 to 310nm in diameter. Most granules contained both FSH and LH, but some contained only one of them. In another type(II)of gonadotropes, the immunreactivity and hormone storage patterns of the secretory granules were similar to those of type I cells. However, the secretory granules were round in shape and larger in size than those of type I. The other gonadotropes(type III) were distinctly distinguished by plenty of hormones in their secretory granules which were densely packed with numerous immunolabelled gold particles. These data are some inconsistent with other results that have been obtained in other ruminants like as cattle and sheep.

The insulin-like growth factor-I(IGF-I) is an important metabolic factor involved in cell growth and metabolism. Although secretion of IGF-I in rat liver is regulated by growth hormone, the effects of forskolin, adenylate cyclase activator, on secretion of IGF-I have not been reported. Therefore, a modified perfused rat liver model was used to investigate the regulatory effects of forskolin on IGF-I secretion in this experiment. The results were summerized as follows: 1. Modified perfused rat liver model was not changed to aspartate aminotransferase(AST), alanine aminotransferase(ALT) and lactic dehydrogenase(LDH) secretion in time. 2. The IGF-I secretion in hepatic cell was increased by forskolin(10-5, 10-6 and 10-7M) in a dose-dependent manner as compared with those of the controls, and significantly increased by 10-5 and 10-6M forskolin(p0.05). 3. Secretion of glucose in hepatic cell significantly was decreased by 10-5M forskolin as compared with those of controls(p0.05). These results suggest that forskolin may be involved in the regulation of IGF-I secretion in the perfused rat liver.

This study was carried out to compare the distribution pattern of the bombesin immunoreactive neurons of the hypothalamic nucleus in the rat and Mongolian gerbil. The bombesin immunoreactive neurons in the rat were located in the dorsal part of the dorsomedial hypothalamic nucleus, but in the Mongolian gerbil inthe compact part of dorsomedial hypothalamic nucleus. From this results, we could get an evidence that there were some differences in the distrbution of peptidebetween rat and Mongolian gerbil.

The effect of isoprothiolane(di-isopropyl-1,3-dithiolan-2-ylidenemalonate) aganist fat necrosis in Hanwoo(Korean Cattle) sire was evaluated. The 10 heads of Hanwoo sire suffering from fat necrosis were given 50mg/kg body weight of isoprothiolane(0.2g/kg of Fujix, Japan) orally once a day for 8weeks. In 30% of these, the size of thenecrotic fat masses had decreased significantly 7 months after the adminstration. Isoprothiolane did not affect on live body weight and semen characteristics. However the sire affected with fat necrosis had higher MCHC(Mean corpuscular hemoglobin concentration) than normal sire inhematologic values 10 weeks after administration. Number of RBC(red blood cell) and PCV(packed cell volume) 10 weeks after administration had been increased than those before administration(p0.05). The serum concentrations of creatinine, triglyceride, and total cholesterol 10 weeks after administration were higher than those before administration while the concentration of glucose was vice versa. the isoprothiolane may reduce the oxidation of glucose, increase the glucose transfer to lipids, and increase blood supply to necrotic masses. These results indicate that isoprothiolane may be useful as the therapeutic agent against fat necrosis.

Field infectious bursal disease viruses 9IBDVs) were isolated from IBDV-suspected commercial chickens. The variable region in VP2 gene of six Korean IBDV isolates (K-IBDVs) and IBD vaccines was examined using the reverse transcriptase/polymerase chain reaction-restriction fragment length polymorphism (RT/PCR-RFLP) assay. With all K-IBDVs and vaccine IBDVs, a 474-bp fragment of the VP2 gene was amplified and tested with various restriction enzymes. Resseriction enzymes BstNI and StyI differentiated K-IBDV isolates and IBD vaccines into four groups. Reseriction enzyme profiles of K-IBDV isolates were different from them of IBD vaccines. K-IBDV isolates except for 310 isolate had specific SspI and TaqI recognition sites, which were recognized in highly virulent IBDVs, but IBD vaccines had no those sites. This study showed that RT/PCR-RFLP assay was thought to be valuable tool for differentiation of IBDVs and identification of highly virulent IBDV.