The relative frequency and distribution of bovine chromogranin(BCG)-, serotonin-, somatostatin(SOM)- and S-100 protein-immunoreactive cells in the intestinal tract of the duck (Anas platyrhynchos platyrhyncos, Linne) with ages were studied using immunohistochemical methods. BCG-immunoreactive cells were detected in duodenum on 23 days of incubation. Thereafter these cells were occurred throughout the intestine. SOM-immunoreactive cells were detected in the small intestine from hatching to 9 weeks. Thereafter they were also observed in colon. Serotonin-immunoreactive cells were detected throughout the intestinal tracts after hatching. These immunoreactive cells were increased with ages except that BCG-immunoreactive cells were decreased with ages from 6 weeks after hatching. BCG- and serotonin-immunoreactive cells were most frequently detected in colon regions and SOM-immunoreactive cells in duodenum regions, but no S-100 protein-immunoreactive cells were detected in this study.

To investigate the involvement of protein kinase C(PKC) isoenzyme in the testes which control spermatogenesis and hormone secretion, we examined cellular distribution of four types of PKC $\alpha$, ${\beta}I$, ${\delta}$ and ${\theta}$ in the horse testes using PKC antisera by western blot analysis and immunohistochemistry. By the western blot analysis, PKC $\alpha$ and ${\beta}I$ were detected at 82KD, while PKC ${\delta}$ and ${\theta}$ were detected at 80KD in the testes of both juvenile and adult horses. In juvenile horse, PKC $\alpha$, ${\delta}$ and ${\theta}$ except ${\beta}I$ were not detected in the cells of the testes, whereas PKC ${\beta}I$ was immunoreacted with only in spermatocytes. In adult, PKC $\alpha$, ${\beta}I$, ${\delta}$ and ${\theta}$isoenzymes were localized in interstitial cells of the testes. In the seminiferous tubules, PKC ${\beta}I$ is localized in spermatocyte, spermatid and spermatozoa, while PKC ${\delta}$ is localized only in spermatids. We suggest that this is a first report to localize PKC in the testes of horse and PKC isoenzymes are upregulated in the cells of horse testes depending on ages. These findings also suggest that certain PKC isoenzyme plays an important role in the signal transduction of spermatogenic cells and interstitial cells in horse testes.

Drug-metabolizing activities of Korean native cattle and swine were investigated from viewpoints of the cytochrome P-450's level, their dependent mixed function oxidase activities, the reactive oxygen species formation and cytosolic enzyme acitivities from each liver homogenates. Level of cytochrome P-450 in the liver microsome of Korean native cattle was $0.28{\pm}0.05nmole/mg$ and that in pigs $0.35{\pm}0.03nmole/mg$. Level of cytochrome $b_5$ of Korean native cattle was $0.24{\pm}0.06nmole/mg$, and that of pigs $0.2{\pm}0.05nmole/mg$, showing no difference between two species. NADPH P-450 reductase were higher in Korean native cattle ($58.3{\pm}5.3nmole/mg/min$) than in pigs ($29.9{\pm}3.8nmole/mg/min$)(p<0.01). The activities of cytochrome P-450 dependent monooxygenases such as ethoxyresorufin O-deethylase (cattle, $96.5{\pm}12.5nmole/mg/min$ ; pigs, $13.6{\pm}2.1nmole/mg/min$), N-benzphetamine N-demethylase (cattle, $5.23{\pm}0.82nmole/mg/min$ ; pigs, $0.76{\pm}0.3nmole/mg/min$) and aniline hydroxylase (cattle, $0.95{\pm}0.1nmole/mg/min$ ; pigs, $0.33{\pm}0.08nmole/mg/min$) were much higher in Korean native cattle than in swine(p<0.01). However, the activity of testosterone $7{\alpha}$-hydroxylase was higher in swine ($90.4{\pm}1.2nmole/mg/min$) than cattle (cattle, $32.8{\pm}1.2nmole/mg/min$). Interestingly, testosterone $16{\alpha}$-hydroxylase, a marker enzyme for P-450 IIA was not detected in both animal species. These results suggest that Korean native cattle and pigs have high contents of P-450 IA1 and P-450 IIIA. Total sulfhydryl compound (cattle, $10.3{\pm}1.1nmole/mg$ ; Pigs, $14.5{\pm}1.8nmole/mg$) and glutathione related enzymes except glutathione reductase (cattle, $38.1{\pm}7.9nmole/mg/min$; swine, $22{\pm}3.6nmole/mg/min$) showed higher levels in swine than in Korean native cattle. Superoxide dismutase (cattle, $7.64{\pm}0.84nmole/mg/min$ ; pigs, $4.47{\pm}0.94nmole/mg/min$) and catalase (cattle, $30.4{\pm}3.7nmole/mg/min$ ; pigs, $17.2{\pm}1.8nmole/mg/min$) were remarkably higher in Korean native cattle than in swine (p<0.05).

$Mg^{2+}$ is one of the most abundant divalent cations in mammalian body(0.2~1.0mM) and the important physiological roles are : first, the cofactor of many enzyme activities, second, the regulator of glycolysis and DNA synthesis, third, the important role of bioenergetics by regulating of phosphorylation, fourth, the influence of cardiac metabolism and function. In this work we have investigated the regulation of the $Mg^{2+}$ induced by ${\alpha}_1-adrenoceptor$ stimulation in perfused guinea pig hearts and isolated myocytes. The $Mg^{2+}$ content of the perfusate or the supernatant was measured by atomic absorbance spectrophotometry. The elimination of $Mg^{2+}$ in the medium increased the force of contraction of right ventricular papillary muscles, and the left ventricular pressure. Phenylephrine also enhanced the force of contraction in the presence of $Mg^{2+}-free$ medium. ${\alpha}_1-Agonists$ such as phenylephrine and methoxamine were found to induce $Mg^{2+}$ efflux in both perfused hearts and myocytes. These effects were blocked by prazosin, an ${\alpha}_1-adrenoceptor$ antagonist. The $Mg^{2+}$ influx could also be induced by phenylephrine and R59022, a diacylglycerol kinase inhibitor. In the presence of protein kinase C(PKC) inhibitors, phenylephrine produced an increase in $Mg^{2+}$ efflux from perfused hearts. Furthermore, $Mg^{2+}$ efflux by phenylephrine was amplified by phorbol 12-myristate 13-acetate(PMA). This enhancement of $Mg^{2+}$ efflux by PMA was blocked by prazosin in perfused hearts. By contrast, the $Mg^{2+}$ influx could be induced by verapamil, nifedipine, ryanodine in perfused hearts, but not in myocytes. $W^7$, a $Ca^{2+}$/calmodulin antagonist, completely blocked the phenylephrine-induced $Mg^{2+}$ efflux in perfused hearts. In conclusion, $Mg^{2+}$ is responsible for the cardiac activity associated with ${\alpha}_1-adrenoceptor$ stimulation. The mobilization of $Mg^{2+}$ is decreased or increased by ${\alpha}_1-adrenoceptor$ stimulation in guinea pig hearts. These responses may be related specifically to the respective pathways of signal transduction. A decrease in $Mg^{2+}$ efflux by ${\alpha}_1-adrenoceptor$ stimulation in hearts can be through PKC dependent and intracellular $Ca^{2+}$ levels.

서방형 돼지성장호르몬(sustained-release formulation of porcine somatotropin, PST-SR)을 1주 간격으로 6차례 피하 및 근육주사하고 혈액과 조직중의 돼지 성장호르몬(PST)과 insulin-like growth factor 1(IGF-1)의 농도를 측정하여 다음과 같은 결과를 얻었다. 대조군의 혈중 PST와 IGF-1의 농도는 각각 2.41과 95.2 ng/ml 이었다. 1. PST-SR을 투여한 후 PST의 혈중농도는 8시간만에 최대에 도달하여(30 ng/ml) 곧 감소하였다. 혈중농도 반감기(decay half life)는 91~227시간이었다. IGF-1의 혈중농도는 투여후 12시간에 최대에 도달하였으며(165 ng/ml), 이후 서서히 감소되었고 반감기는 77~99시간이었다. 2. 혈중 PST농도-시간의 자료는 제재에서 PST가 유리되는 과정에는 두단계 즉, 투여후 24시간까지의 유리속도가 빠른 단계와 그 이후의 유리속도가 느린 단계가 있음을 보여주었다. 3. 여섯번의 반복투여기간에는 PST의 혈중농도는 투여직후 증가하여 24시간 이후 다음 투여전까지 지속적으로 감소되는 패턴이 반복되었고, 최종투여후 1주일경에는 정상수준으로 회복되었다. 반면에 투여가 반복됨에 따라 매 투여직후의 PST의 혈중 최고치는 다소 증가되는 경향을 보였다(20~40 ng/ml). IGF-1의 혈중농도는 투여가 반복됨에 따라 누적적인 증가현상이 뚜렷하였으며, 이후 2주일후 까지도 정상농도보다 높게 유지되었다(200ng/ml). 임상용량 투여군에서 PST 및 IGF-1의 혈중농도는 투여경로에 따른 차이는 나타나지 않았다. 4. 최종(6번째) 투여후 6, 8, 10, 14일에 조사한 간장, 신장, 소장, 근육, 지방 및 주사부위의 조직중의 PST 농도는 6일째에 이미 대조군 수준으로 회복되었다. IGF-1의 경우 최종투여후 6일에는 간장, 신장, 소장, 지방조직에서 정상보다 높은 농도로 잔류하나 이후 14일까지 모두 대조군 수준으로 감소되었다. 5. 이상의 결과는 본 실험에서 사용된 서방형 PST제제는 최소 1주간 유효성이 유지되며, 동시에 PST는 투여 6일째에, IGF-1은 투여후 14일에 정상수준으로 회복됨을 보여주고 있다.

Total of 1085 swine sera (1996-1997) from nation-wide were tested for the presence of antibodies to influenza A virus. Fifty nine percent of the tested sera showed seropositive by HI test. Positive sera consisted of 24--- of H3, 15--- of H1, and 20--- of the sample had both antibodies, respectively. Sera collected from various region represented 7~27--- seropositivity to H1N1, 15~25--- to H3N2, respectively. Swine influenza field isolate from nasal swab was characterized antigenically and genetically to elucidate its relatedness with other known strains of influenza A virus. The study was focused on the HA gene which is related to pathogenecity and antigenic variability of the influenza virus. By RT-PCR using influenza A/H1N1 specific primers, influenza virus H1N1 specific DNA fragment was amplified from A/Swine/Iowa/15/30(H1N1), US field isolate but not in H3N2 strain. PCR products were sequenced by dideoxy chain termination method to determine nucleotide homology with other strains of influenza A virus. The US field isolate and A/Swine/Indiana/1726/88 strain had 97--- of nucleotide homology and 98--- of amino acid homology. Based on the results obtained from this experiment, the field isolate was genetically related to A/Swine/Indiana/1726/88 and had higher homology with A/Swine/Indiana/1726/88 than with classical swine influenza virus, A/Swine/Iowa/15/30. The field isolate had no amino acid changes at the antigenic site compare to that of the A/Swine/Indiana/1726/88. The proteolytic enzyme cleavage site between HA1 and HA2 had no alteration and the amino acid arginine was intact. There is no evidence has been found that the field isolate has genetic shift or genetic drift which might altered antigenic determinant.

국내분리 소 로타바이러스의 genomic RNA 형태, 분리주간의 교차면역반응 그리고 단클론 항체를 이용한 중화시험에 의해 혈청형을 조사한 바 다음과 같은 결과를 얻었다. 국내분리주들의 genomic RNA 형태는 크게 NCDV 형태(7/11 시료)와 non-NCDV 형태(4/11 시료)의 두가지로 나타났다. 교차면역시험에서 표준주인 NCDV주에 대한 양성혈청은 국내분리주들에 대해서는 비교적 낮은 중화력을 나타내었으나 국내분리주에 대한 양성혈청들은 타 국내분리주 뿐만 아니라 NCDV주에 대해 서로 높은 중화력을 나타내었는데, 분리주 중 678, P44, M4에 대한 양성혈청은 NCDV를 포함한 대부분의 분리주에 대해 100%의 중화력을 나타내었다. 또한 288주에 대한 양성혈청은 288, 678,P44, M4주에 대해서는 높은 중화력을 나타내었으나 다른 분리주들에 대해서는 비교적 낮은 중화력을 나타내었다. 국내분리주의 단크론 항체를 이용한 G혈청형 감별결과는 G6유사형이 45.8%(11/24주), G10 유사형이 54.2%(13/24주)로서 두가지 G형이 존재하였다. 한편 G6형에 반응한 것들의 P형은 표준주인 NCDV주(P1)와는 다른 것으로 확인되었으며, G10 유사형에 속하는 14주는 모두 P11 혈청형으로 판명되었다.

The effects of chitosan on mastitis in lactating holstein cows were evaluated. Fifty six cows with intramammary infection(IMI) from nine farms were selected and the cows were fed with diets which contained 15~20g chitosan per day for 5~7 days. The milk samples were obtained from cows at 7 days and 14 days after administration to determine effect of the curing of mastitis and the reduction of somatic cell counts(SCC). The average value of SCC levels in quarter milk from the cows administrated with chitosan significantly decreased up to 31.8% and 47.7% at 7 and 14 days, respectively(P<0.05). The cure rates of chitosan for Stapylococcus aureus, coagulase-negative Staphylococci, Streptococci spp, other gram positive bacteria and coliforms were 30.4, 42.8, 33.3, 66.6 and 54.5 % respectively. Twenty three out of 64 cases were cured by feeding with chitosan. The results showed that administration of chitosan could reduce SCC in milk and improve cure rates of bovine mastitis caused by microorganisms. The further studies will be pursued to study on the mechanism of chitosan in the immune responses of cows with mastitis.

돼지 생식기호흡기증후군(porcine reproductive and respiratory syndrome, PRRS) 바이러스가 웅돈에 감염되었을 경우에는 정충의 기형 등 정액의 질 저하와 더불어 정액에 바이러스가 함유되어 있어 종부시 모돈에 바이러스를 전파하는 것으로 알려져 있다. 감염된 웅돈의 정액으로 인공수정을 실시할 경우 농장의 모돈 전체에 순식간에 바이러스를 전파하여 막대한 피해를 유발할 가능성이 높다. 따라서 감염웅돈을 신속히 검색하여 격리함으로써 피해를 사전에 방지해야 하며, 이를 위해서 웅돈의 감염여부를 신속히 확진하는 진단법의 개발이 필요한 실정이다. PRRS의 진단을 위해서는 바이러스학적인 진단법으로는 바이러스 분리동정, 혈청학적인 방법으로 바이러스 분리동정이 필수적이나 검사시간이 많이 소요되고, 분리동정 자체가 까다로운 단점이 있다. 본 연구에서는 웅돈의 정액내에서 PRRSV 바이러스에 대한 유전자를 RT-PCR법으로 증폭하는 방법을 개발하였으며, 진단의 민감도를 높이기 위하여 Nested PCR법으로 재확인 할 경우, 바이러스의 역가가 $1TCID_{50}$만 함유되어 있어도 진단이 가능한 조건을 확립하였다. 이 방법을 이용할 경우 웅돈의 정액시료에 대한 PRRS 바이러스 감염여부를 신속, 정확하게 검색하여 감염웅돈을 통한 PRRS바이러스의 전파를 미리 차단할 수 있으므로 PRRS방제에 효과적으로 이용될 것으로 사료된다.

본 연구에서는 돼지 로타바이러스의 혈청형 A, B 및 C를 동시에 진단할 수 있는 RT-PCR 기법을 개발하였다. 각각의 혈청형에 특이적인 primer를 이용하여 RT-PCR 기법으로 분변시료에서 직접 바이러스 동정을 실시한 결과, 23건의 로타바이러스 감염 분변 시료에서 13건이 혈청형 A, 3건이 혈청형 B, 2건이 혈청형 C로 나타나 국내에서도 A, B 및 C형의 돼지 로타바이러스가 공히 발생하고 있음을 확인하였으며, 발생분포는 외국의 예와 유사하였다. 이 RT-PCR기법은 돼지 로타바이러스의 주요 혈청형인 A, B 및 C형의 동시감별진단법으로 이용될 수 있을 것으로 판단된다.

The immunogenetic analysis was performed to characterize the Korean native chickens (KNC) determined by monoclonal antibodies specific to chicken leukocyte differentiation antigens and flow cytometry. A total of 174 chickens including 58 KNC (black, brown and darkbrown colored), 77 foreign breed (Nagoya, White Reghorn, Rhode Island and Cornish) and 39 mixed breed (19 KNC with Nagoya and 20 KNC with Rhode Island) separately growing at Animal Science and Technology Institute were examined. The proportion of cells expressing MHC class II molecule (B-L in chicken) was significantly high in KNC. Proportion of CD4+ T helper cells was also higher in KNC and two mixed breed than that in foreign breed. However, proportion of CD8+ cells and TCR1 + (${\gamma}^{\delta}$ T cell receptor) cells was the lowest among the breed examined. Otherwise, those proportions were significantly high in White leghorn and two mixed breeds with two exclusive subpopulations. The two subpopulations were also typically shown in MHC class $II^+$ cells in KNC and one mixed breed, black-colored KNC with Nagoya. Although genotypic analysis was not pursued to characterize the immunogenetic properties of KNC, difference of phenotypic expression based on leukocyte differentiation molecules could be elucidated in KNC in this study.

The present study attempted to apply polymerase chain reaction (PCR) to develop a rapid differential diagnosis among Marek's disease, reticuloendotheliosis and avian leukosis. The primers chosen to detect Marek's disease virus (MDV) flank the 132bp tandem direct repeat of the MDV genome. The primers selected for reticuloendotheliosis virus (REV) and avian leukosis virus (ALV) are based on proviral long terminal repeats of spleen necrosis virus and Rous-associated virus-2 genomes, respectively. The specific PCR products of MDV, REV and ALV were observed with each primer and the reaction was not cross-reacted among the viruses. MDV-specific DNA was also amplified from the MDV-induced lymphoma (MDCC-MSB1) but not from the REV-induced tumor and ALV-induced lymphoma (LSCC-1104B1). In addition, proviral DNA of REV from REV-induced tumor and proviral DNA of ALV from ALV-induced lymphoma were also amplified by REV-specific and ALV-specific PCRs, respectively. Therefore these three PCR methods may be used to rapidly differentiate among MDV, REV and ALV-associated tumors in diagnosis.

The cultivation for development of Ascaris suum from the second-stage larvae($L_2$) embryonated egg and the third-stage of rat-derived larvae($L_3$) recovered from lung of rats were performed to use the screening test of anthelmintics in vitro. The preparations of larvae for cultivation were that the artificially-hatched $L_2$ incubated the embryonated eggs of Ascaris suum in 0.1% formalin solution at $25^{\circ}C$ for 28 days and the rat-derived larvae($L_3$) recovered from the lung of rat infected with the embryonated eggs of Ascaris suum on 7 days after infection(DAI). The cultivation for development of Ascaris suum from the embryonated eggs($L_2$) and the rat-derived larvae($L_3$) for 14 days in RPMI medium 1640(with 5% bovine calf serum) were as follows : 1. The sizes of the liberated larvae($L_2$) which were artificially hatched from embryonated eggs with glass beads(diameter 5mm) were $190{\sim}250{\mu}m$ on 1 days in culture(DIC). The second-stage larvae were molted into third-stage larvae(early $L_3$; $250{\sim}300{\mu}m$) and the features of these larvae were first observed such as cephalic cuticle, esophageal lumen and anus etc. on 5 DIC and the sizes of late third-stage larvae were $250{\sim}450{\mu}m$ on 10 DIC. The sizes of early fourth-stage larvae($L_4$) were $500{\sim}700{\mu}m$ and the features of these larvae were more pronounced in internal organs on 15 DIC. 2. The sizes of third-stage larvae($L_3$) recovered from the lung of rats were $1,340{\sim}1,370{\mu}m$ and the feartures of cephalic cuticle, esophageal lumen, intestine, rectum, anus were visualized by inverted microscope on 1 DIC. The fourth-stage larva($L_4$) completed by third ecdysis were recognizable and sizes of early fourth-stage larvae were developed as $1,400{\sim}2,200{\mu}m$ on 5 DIC. The sizes of middle fourth-stage of larva were $1,900{\sim}2,300{\mu}m$ and the thickened epithelial rectum was observed on 10 DIC. The rectum and anus of late fourth-stage larva($L_4$ $2,500{\sim}3,200{\mu}m$) had developed completely in RPMI medium 1640 on 15 DIC.

This study was performed to investigate the pathogenesis of hepatic granuloma and hepatic fibrosis induced in mice infected with Capillaria(C) hepatica and treated cyclophosphamide. The results were as grossly well-defined yellowish white spots and small nodules at the surface of the liver were scattered. Histopathologically, there were numerous granulomas composed of eggs and fragments of C hepatica surrounded by heavy infiltration of inflammatory cells. Severe fibrosis was observed around granulomas. Pathological lesions of group infected with C. hepatica and then injected with cyclophosphamide were most severe than those of other groups. Therefore this study suggested that hepatic fibrosis induced by C hepatica in mice would be useful for animal model of hepatic fibrosis in human.

Avian coccidiosis is a very important disease of poultry industry. In recent years, many researchers studied for the immunology of avian coccidiosis. Coccidial vaccines have been used at some poultry farms in many countries. In order to evaluate the anticoccidial effects of coccidial vaccine to chicken treated with anticoccidial drugs, 4 week-old chicken were administered anticoccidial drugs and challenged with avian coccidia at 2 weeks after vaccination of coccidia. The body weight gains, lesion scores, oocyst indices and anticoccidial indices of chicken were investigated at the time of vaccination, challenge and necropsy. The body weight gains and feed conversion rates of groups immunized with coccidial vaccine and treated with anticoccidial drugs were moderately higher and lower than those of groups treated with anticoccidial drugs, respectively. The lesion score and oocyst indices of all groups immunized with coccidial vaccine and/or treated with anticoccidial drugs were milder than those of infected control groups. The anticoccidial indices of groups immunized with coccidial vaccine and treated with anticoccidial drugs were moderately higher and lower than those of groups. treated with anticoccidial drugs. But all of the investigated items were not statistically significant.

To investigate the effect of acupuncture on bovine parasitosis, we first surveyed the prevalence of parasite by fecal sedimentation and floatation techniques, and Giemsa stain for blood parasites. Coccidia were the most frequent parasite(22.1%), which followed by Buxtonella sulcata. Others were very few. After acupuncture, infection rates of Coccidia and B sulcata started to decrease at 1 day after acupuncture(DAA) and reduced to 5.3% and 0% at 7 and 21 DAA, respectively. In comparison between treated and control groups, due to small sample number, statistical evaluation was impossible. But diarrhea of treated group was slightly decreased, while, haemoparasites infection rate is decreased in control group. To gain the confident result of acupuncture effect, the more investigation is needed.

The Neospora sp. was isolated from the brain of 1 calf via continuous in vitro cultivation in Vero cell. Neospora tachyzoites were observed 45 days after inoculation of the homogenized brain suspension into the Vero cell. The isolated parasite (named tentatively as NCKB-1) was morphologically and ultrastructurally similar to the previously reported Neospora sp isolated in cattle (BPA-1, JPA-1). A comparison of the antigenic reactivity of cultivated tachyzoites with polyclonal antisera to Neospora caninum and Toxoplasma gondii confirmed that this protozoal isolate was similar to N caninum. This is the first report of successful isolation of Neospora sp from cattle in Korea.

A survey of the internal parasites in 115 fishes of Ophicephalus argus was carried out in Kyungpook province during the period from January 1995 to November 1997. A species of trematode from the stomach and a species of nematode from the caeca of the fishes was discovered respectively. The trematode was identified as Azygia hwangtsinyi (Tsin, 1993) and the nematode as Pingus sinensis ($Hs\ddot{u}$, 1993). The fluke was pressed at thick of 0.1mm~0.2mm between slide glasses and fixed in 70% ethyl alcohol solution. The fluke was washed with tap water after fixation and stained with hematoxylin-carmin and mounted in balsam through routine methods. The nematode was fixed in 5% formalin solution and mounted with lactophnol or glycerine jelly. Morphology : Arygia hwantsinyi ; The fluke is elongate body with approximately parallel margins and rounded extremities in pressed preparations(Fig 1). The cuticle is unarmed. The oral sucker is ventro-subterminal in position. The ventral sucker is slightly smaller than oral sucker and positioned at 14.2% of body length from the oral sucker. The cirrus sac and genital pore is in mid-ventral line, slightly anterior to the ventral sucker. The oral sucker is succeeded by a well developed muscular pharynx. It is succeeded by a short inverted Y-shaped oesophagus. The inner wall of oesophagus is consisted of many fine folded membrane. The fine tubes of esophagus pass into the intestinal heads which are distended and presented a marked borderline between the fine tube and intestinal heads. The Intestinal heads start at level of pharynx and pass caudad in a zigzag course to end quite near caudal margin. The uterine coils occupy the intercecal area between the level of the cephalic margin of the ovary and about the level of the ventral sucker. The uterus is filled with many eggs. The testes are round or oval and placed one behind the other generally a little diagonally. The posterior testis is placed at level of 75.1% of body length. The ovary is oval, placed ahead the anterior testis. The shell gland not discernible outline is contacted with ovary ahead it. The vitelline glands are consisted of small oval vesicles. The vesicles occupy extracecal regions and between a little posterior of the ventral sucker and near caudal margin. Pingus sinensis : Female ; The cuticle is smooth and the cervical alae are well developed. The mouth opening is small, triangular, and without lips. The anterior end bears four sub-medial papillae. The oesophagus is divided into a muscular and glandular portion. The nerve ring is situated just at the junction of the muscular and glandular portions of the oesophagus. The vulva which has a prominent flap, is placed behind the middle of the body about one-third of the length of the worm from the posterior extremity. The vagina is strongly muscularised and after running anteriorly about $68{\mu}$, divides itself into two broad uterine tubes with an anterior and a posterior one. There are a few eggs in the uterine tubes. The tail is slender, straight and pointed. The ovary extends almost to the posterior extremity. Male : Male is smaller than female. The tail is pointed, curved and carrying well-developed caudal alae. A prominent muscular precloacal sucker is characteristic. The spicules are equal and short. There are four pairs of pedunculated pre-anal papillae, of which the most anterior pair are situated just at the level anterior to the muscular sucker. Two pairs of pedunculated papillae are present before the anus. There are five pairs of post-anal papillae of which the most anterior pair and the second counted from the posterior end are ventral and more marked than the ones which are situated laterally.

Fasciola hepatica eggs were obtained from the bile of infected cattle at a local abattoir. Metacercariae(MC) were produced using Lymnaea viridis, the intermediate host of the parasite. They were stored in distilled water at refrigerator($3{\sim}5^{\circ}C$) and at room temperature($22{\sim}27^{\circ}C$). The viability and infectivity of the MC were determined at monthly intervals for 12 months. The viability was determined by both microscope and excystation, and the infectivity by infecting mice. The MC stored at room temperature had a high viability up until 60 days, and thereafter the viability declined rapidly ; at day 120, only 2.5% of the MC were excysted. Most of the MC stored at refrigerator retained the viability up until 90 days, and thereafter the viability declined slowly ; about half of them were viable at day 210 and 5% of them retained the viability until day 270. The survival rates of the MC determined by microscope were always higher than those determined by excystation(p<0.05). The infectivity of the MC wisely followed the viability at the two different storage temperatures. Most of the mice infected orally with the MC died within 3-9 weeks of acute fasciolosis.

한국 및 일본을 포함한 동아시아 지역에 벡터 매개성 바이러스에 의한 소 질병으로 인하여 경제적 손실이 몇년을 주기로 극심하게 나타나고 있다. 그러나 본 질병의 정확한 역학에 대하여는 아직까지 확실한 연구가 되어 있지 않은 상태이다. 본 연구에서는 벡터 매개성 질병에 대한 역학을 좀더 명확하게 밝히기 위하여, 일본 열도중 가장 멀리 떨어져 있으며, 아열대 지역에 속하는 오끼나와 섬에서 사육되고 있으면서 백신접종을 받지 않은 소(Japanese black cattle)를 대상으로 하여 1988년도부터 1992년도에 걸쳐 벡터 매개성 바이러스군에 대한 중화항체가를 측정하고 분석하였다. 소의 유행성 바이러스(bovine ephemeral virus)에 대한 항체 양성율은 연도 및 계절별로 크게 변화를 보였고, Ibaraki virus에 대한 항체양성율은 그 어느 다른 계절보다도 5월에 높은 항체가를 보였으며, Akabane virus에 대한 항체 양성율은 이바라키 바이러스에 대한 항체 양성율과 유사한 수준으로 나타났다. 한편 Chuzan virus에 대한 항체양성율은 계절적인 변화가 심하지 않은 것으로 나타났다.

Esherichia coli O157 : H7의 slt I, slt II, uid A 및 eaeA 4종 유전자를 동시에 검출하기 위한 multiplex PCR 기법을 확립하고 쇠고기중 직접 E coli O157 : H7 검출시험을 실시하였다. 4 set의 primers를 이용한 multiplex PCR 기법으로 31종의 장내세균에 대한 특이성을 조사한 결과 E coli O157 : H7 에서 1,087bp (eae A), 584bp (slt II), 348bp (slt I) 또는 252bp (uid A)크기의 DNA를 동시에 특이적으로 검출할 수 있었다. E coli O157 : H7 15주는 모두 uid A 및 eae A 유전자가 동시에 검출되었고, 다른 장내세균에서는 검출되지 않았다. slt I 또는 slt II 유전자를 가지고 있는 E coli 표준균주 24종을 이용하여 multiplex PCR 기법과 Vero cell cytotoxicity assay을 비교검사한 결과 베로톡신 산생능과 PCR법의 결과는 일치하였다. mutiplex PCR 기법의 쇠고기중 검출한계는 modified EC(mEC)에서 증균없이는 E coli O157 : H7균 $10^4cells/g$ 이상에서 검출이 가능하였으나 mEC에 1차 증균후 modified TSB 증균하였을 경우에는 10cells/g이하까지도 검출이 가능하였다. 개발된 multiplex PCR 기법을 쇠고기 40종에 직접 적용한 결과 E coli O157 : H7은 검출되지 않았으나 slt I 및 slt II유전자를 가지고 있는 E coli 4종이 검출되었으며, 이들의 혈청형은 O6, O112, O115 및 O139 였다. 이 연구에서 개발된 multiplex PCR은 쇠고기중 E coli O157 : H7을 신속하고 특이적으로 검출하는데 사용할 수 있을 것으로 사료된다.

The effects of electroacupuncture(EA) on gastrointestinal motility were investigated in 6 horses. Three acupuncture points ; Guan Yuan Shu(BL-26), Wei Shu(BL-21) and Da Chang Shu(BL-25) were stimulated for 20 minutes by EA at separate occasions under varying condition ; 2V-1Hz, 2V-5Hz, 2V-30Hz, 4V-1Hz, 4V-5Hz and 4V-30Hz. Myoelectric activity of stomach and cecum was monitored to investigate the gastrointestinal motility. Electromyogram(EMG) recordings were carried out before, 0, 20 minutes after and 40 minutes after the EA stimulation. EMG bipolar electrode was surgically implanted in seromuscular layer of greater curvature in the stomach and between medial band and ventral band in the cecum. The EA stimulation and monitoring were not commenced until 15 days after electrode implantation. The EA stimulation of Wei Shu influenced on stomach motility and that of Da Chang Shu on, cecum motility. However, the EA stimulation of Guan Yuan Shu influenced on both the stomach and the cecum motility. The myoelectrical spike burst amplitude of the stomach and the cecum was significantly(p<0.05) increased by 2V-1Hz stimulation, but the myoelectrical spike burst frequence of the stomach and the cecum was significantly decreased by 2V-30Hz or 4V-30Hz stimulation. The myoelectrical spike burst duration of the stomach and the cecum was significantly lengthened by 4V-30Hz and 2V or 4V-30Hz stimulation, respectively.

Piglets' diarrhea is one of the major causes of economic loss in Korean swine industry. To prevent this serious and persistant problem, we have developed systemic farm evaluation and analysis program. The program consists of the checklist and the computerized program. The items of the checklist are selected on the basis of various causative factors related with the piglets' diarrhea including sanitational status, nutritional management, or farm environment. The checklist is composed of 30 items including 6 factors on facility, 8 factors on environment, 6 factors on nutrition and 10 factors on sanitation, respectively. Minimum 1 to maximum 10 points was assigned to each item depending on level or status of farm. The scores calculated by sum of points obtained from each item could find out the problems which the farm was confronted with. To investigate the applicability of a program 150 swine farms raising over 500 heads were selected from 7 provinces throughout the country and surveyed. There were significant correlations between the piglets' diarrhea and the scores of the checklist. Based on above results we revised the checklist which consisted of 22 items including 5 factors on facility, 7 factors on environment, 3 factors on nutrition and 7 factors on sanitation. After that we composed a computerized diagram out of each point of an item which showed and indicated weak factors to be improved promptly. Our present study suggested that this newly established swine farm evaluation program would be a very efficient way to find out the problems and support the systemic control program of the piglets' diarrhea for swine farms.

The purpose of present study is to improve the efficiency of fusion and the developmental rates of nuclear transplanted embryos to produce genetically identical twins from Korean native cattle. The diameter of aspirated follicles had no significant effect on the recovery rates of oocytes collected by ovum pick-up technique. The fusion rates of nuclear transplanted embryos were significantly higher in 50 and $100{\mu}s$ DC duration groups(73.3 and 72.0% ; respectively) than that in $30{\mu}s$ group(55.6% ; p<0.05). The cleavage rates of nuclear transplanted embryos appeared to be significantly higher in donor nuclei derived from in vivo (65.0%) than in those from in vitro (50.5% ; p<0.01), but the developmental rates to morulae and blastocysts were not significantly different between them(13.7 vs 10.9%, respectively).

영국 Hertfordshire의 두지역에서 사육되고 있는 건강한 조랑말의 결막낭내 상존하고 있는 진균총의 분포도를 조사 비교하고자 36두 조랑말의 양안(총72안)의 상 하 결막낭에서 시료를 채취하여 진균을 분리 동정하였다. 총 76.4%의 안구에서 진균이 발견되었으며, 13종이 분리되었다. 전체적으로 가장 많이 분리된 진균은 Aspergillus spp(27.8%), Nocardia spp(25.0%), Cladosporium spp(19.4%), Penicillium spp(9.7%) 및 Penicillium spp(9.7%)순이었다. 1지역에서는 Nocardia spp와 Cladosporium spp가 가장 많이 분리된 반면, 2지역에서는 Aspergillus spp가 가장 많이 분리되었다. 상 하결막낭내 진균분리율의 차이는 상결막낭에서보다는 하결막낭내에서 진균이 유의성 있게 많이 분리되었다(p<0.05). 시료채취시에 사용된 swab의 상태에 따른 비교에서 건조된 swab과 젖은 swab간에는 통계적 유의성이 없었다.