The present study was carried out to investigate the pathogenicity and pathogenesis of wild rats(Rattus norvegicus), trapped in nature, intranasally infected Aujeszky's disease virus(ADV/NYJ-1-87) by histopathology, immunohistochemistry and in situ hybridization(ISH). Fifteen rats inoculated intranasally were roughened haircoat, anorexia, listlessness, and depression second day after inoculation, and three rats died in 66-72 hours. Eight rats showed severe pruritus at the fact that was accompanied by frequent face-washing movements of the forelegs, and then became violent and spasmodic for and hour or until they died. Four rats slowly recovered after showing mild clinical signs of the disease. Microscopic lesions in infected rats were characterized by meningitis, perivascular round cell infiltration, focal gliosis, and neuronal degeneration and necrosis. And intranuclear inclusion bodies were frequently detected in the cerebral cortex and medulla. Positive reaction to ADV by immunohistochemistry and ISH were detected in the following areas:trigemimal ganglion, brain, tonsil, nasal mucosa, spleen, lung and liver. The result has suggested that ADV intranasally infected in wild rats is followed by replication in epithelial cells of nasal mucosa and tonsil, then invade local lymph nodes by way of the lymphatics. It is also believed that the virus invades bipolar olfactory cells and trigerminal ganglion, and then spread into central nervous system.

This study was designed to evaluate the effect of cyclophospaide(CY) on dietynitrosamine(DEN)-induced hepatic tumors in rats. Thirty five male of femal Sprague Dawley rats were continiously given water containing O.01% DEN for 10 weeks and then were give with CY 25mg/rat/day in water for 3, 5, 7 or 9 days. The livers of rats were removed and fixed in 10% buffered neutral formalin. The appearances of positive cells by immunohistochemical methods using proliferating cell nuclear antigen (PCNA) antibody, p53 antibody and apoptotic kit were investigated. The livers of rats given with CY were grossly brilliant, red-brown color, flexible, and thin border, and stainability of the liver cells were restored microscopically, and the vaccuolated and degenerated regions were differentiated from restored regions. These restored findings also were advanced in control group becouse of no DEN treatment but tended to be less avanced. In immunohistochemistry, positive cells to PCNA antibody appeared more numerous in control groups than that of CY treated groups. Appearance of positive cells in CY-treated group for 7 days and for 9 days were more numerous than those of CY-treated groups for 3 days and for 5 days, respectively. So these findings suggested that CY suppressed cell proliferations and effects of these action were decreased with CY-treated days. The numbers of positive cells to PCNA antibody were more prominent in hepatocelular carcinoma regions and cholangiocarcinoma regions, and then were ranked as order of large liver cell regions and normal liver cell regions. Also the numbers of the positive cells by apoptotic kit tended to be higher in hepatocelular carcinoma regions and cholangiocarcinoma regions but not uniformly in order in all regions nd were much less numbers than those of OCNA positive cells. So immunohistochemical methods using PCNA antibody together than using apoptotic kit alone when anti-carcinogen experiments. Rats with positive cells by p53 antibody were 11 of 15 rats(73.4%) in control groups and 12 of 18 rats(66.7%) in CY treated group, respectively. These positive cells appeared focally in early vacuole-occurring regions and were low in numbers.

From 2,373 slaughtered pigs examined, 1,899 of them had visible evidence of pulmonary lesion. The lungs with pulmonary lesion were examined by grossly, histopathological technique to investigate the prevalence accordint to season, severity ofpulmonary lesion, types of the pneumonia and relationship between rearing management and prevalence of pulmonary lesion. The results were as follows: 1. Prevalence of pneumonia according to season was 72.3 % to 85.9% and the higher prevalence was in winter. 2. In the severity of pulmonary lesion, rates mild, moderate and severe lesions were 38.3%, 47.0% and 14.7%, respectively. Prevalence of mild lesion was the highest in autumn. Prevalence of moderate and severe lesions was the hihgest in winter. 3. In the type of pneumonia, rates of interstitial pneumonia and bronchopneumonia fibrinous pneumonia were 23.6%, 13.0%, and 3.4%, respectively. Prevalence of interstitial pneumonia was high in spring and autumn while that of broncho-pneumonia and fibrinous pneumonia was high in winter and summer, respectively. 4. In relationship of pulmonary lesions according to severityo fpulmonary lesion and types of pneumonia, similarity was observed in prevalence of mild lesion and bronchopneumonia.

We performed this study to evaluate the potential clinical marker of urinary trypsinogen-2 together with amylase, lipase and urinary amylase creatinine clearance ratio (ACCR) for the diagnosis of acute pancreatitis in dogs. In the experiment on daily changing pattern of amylase, lipase and ACCR measurements in experimentally induced pancreatitis dogs, compared to values measured in pre-induction state, significant difference was seen in amylase until 5th day of induction, and for lipase significant difference was found during the 7th day of observation period (p0.05). No significant difference was found in ACCR for the study period (p0.05). On SDS-PAGE analysis of urine from experimentally induced pancreatitis dog, The 26kd band was markedly increased compared with that of normal state and that band was confirmed trypsinogen-2 using substrate interaction and isoelectric focusing assay after being eluted. When assessing the appearance of 26kd band on urine SDS-PAGE 87.1% (range:50~100%) of experimentally induced pancreatitis dogs showned positive results, whereas no corresponding band was seen in dog without pancreatic disorders. With this result, determination of urinary trypsinogen-2 assay was found to have a high diagnostic value with a 70% of sensitivity and 100% of specificity as a routine test for pancreatitis, although the detection of trypsinogen-2 in urine can be varied on the progressionstage of pancreatitis at the initial visit to animal clinic. We therefore suggest that the promising results in this study be used for the development of dipstick test for detecting acute pancreatitis in the future research.

Two-day old house fly adults were exposed to six insect growth regulators, flufenoxuron, teflubenzuron, triflumuron, diflubenzuron, methoxyfenozide, tebufenozide, as a feed additive (milk + 5% sugar + chemical) in the laboratory for 6 days. The number of eggs deposited by the exposed-adults, viability of the eggs, and F1 larval development were checked. All the IGRs tested were found to have no adverse effect on the reproduction of house fly, except methoxyfenozide (210ppm). The most effective inhibitor to egg hatch was flufenoxuron, followed by teflubenzuron, triflumuron, and diflubenzuron. Exposure to flufenoxuron (over 5ppm), teflubenzuron (over 25ppm), triflumuron (over 125ppm), and diflubenzuron (over 125ppm) reduced egg hatchability to 0 to 1.3%, but lower concentrations of these IGRs were less effective (6.3 to 46.3% egg hatchability). Almost all the larvae emerged from eggs deposited by the adults exposed to diflubenzuron (62.5ppm) and teflubenzuron (12.5ppm) failed to develop into pupae, causing total mortalities of 98% and 100%, respectively. However, two IGRs, methoxyfenozide and tebufenozide, did not inhibit egg hatch and F1 larval development, except methoxyfenozide (210ppm) treatment. These results suggest that these 4 IGRs may be used in the development of autosterilization system for house fly control. However, further work is required to develop delivery systems capable of transferring an effective dose to the fly under field conditions.

We have developed in situ hybridization(ISH) technique for rapid diagnosis of canine distemper(CD) which is the major infectious disease in dogs. In our experiment, we rapidly detected distribution of the specific canine distemper viral genome without disrupting morphology of tissues of cells. Two oligonucleotide probes for ISH were synthesized chemically and labelled 5' end with nonisotopic biotin by DNA synthesizer. The whole procedures of ISH was completed within 1~2 hours using the Microcapillary action system. On histological study, typical cytoplasmic or intranuclear inclusion bodies wer observed in the trachea, bronchiole, brain, and urinary bladder with the presence of prominent red positive signals on ISH, indicating specific CDV genome from the paraffin-embedded tissues of infected 13 cases. The results showed ISH can be used as a rapid and effective diagnostic method for diagnosis of CD.

Sal enteritidis thin fimbriae, SEF14, were found to be restricted to the predominantly poultry-associated members of the Salmonella serogroup D1 that are considered as the important pathogens in poultry industry. SefA together with sefB and sdfC encode the proteins involved in SEF14 biosynthesis. In order to develop the rapid and specific detection methods for Salmonella serogroup D1, a PCR technique for the am;lification of sefA gene was established, and its specificity and sensitivity were investigated with various microorganisms. The bacterial genomic DNA was extracted by colony-picking and rapid boiled-lysate technique. In comparison of SefI and SefII primers used in the PCR. SefI primer for sefA gene of 513bp showed higher specificity than that of SefII. The established PCR was s sensitive as to detect 1pg of Sal enteritidis DNA. When 73 strains in 28 genera including the reference strains and the field isolates of various Salmonella serotypes, Bacillus subtilis, Bordetella bronchiseptica, E coli, Listeria spp., Micrococcus luteus, Rhodococcus equi, Staphylococcus spp., Streptococcus spp., Vibrio parahemolyticus, Yersinia spp. were studied, the established PCR yielded specifically positive results with only Salmonella serogroup D1. The results suggested that the PCR for sefA gene could be a potential candidate among the specific detection methods for Salmonella serogroup D1.

Staphylococcus aureus is one of most prevalent intramammary pathogens and have characteristics which are not easily eradicated. Recently, to understand the sources and transmission of S aureus, many studies have focused on the subtyping of field isolate. This study was preformed to investigate the distribution pattern and characteristics of the isolates using phenotyping and genotyping. Samples were collected from milk of each udder, cow bodies (perianal region, vagina, tail, udder skin, sole) and environment (floor, liner, milker's hand, water, towel, insect) from 6 herds located in Kyung-gi province. Forty five strains of S aureus were isolated from 3 dairy herds (A, B, C) and were typed by hemolytic pattern, antibiotic resistant pattern, enterotoxin typing and PCR-based DNA fingerprinting. Slime productivity was also compared by each subtype to examine potential infectiousness. Of 45 strains, 41 were isolated from milk samples and 4 were isolated from liners. No strains isolated in the bodies and environment. Forty five strains isolated were classified as 18 subtypes by phenotyping and genotyping. There was common subtype between A and B herd, but the subtype of C herd showed different pattern. Among predominant subtypes, 60% of S aureus strain isolated from A and B herd showed subtype I and 50% of S aureus strain isolated from C herd belong to subtype VI and XII. Neither somatic cell count (SCC) nor slime production was significantly different between predominant and minor subtypes. In summary, the study revealed that liners play more important roles in the mode of transmission than enmironmental sources. Several subtypes can be found in a herd, only a few subtype, however, was largely associated with the majority of infection.