Although it has been reported that hormones or chemicals, which increse in intracellular cAMP, produced Mg2+ release from the heart, it is not well characterized whether a specific Mg2+ exchanger is involved in cAMP-induced Mg2+ efflux in themammalian hearts In this work, we studied the relationship between the increase in intracellular cAMP and ion transport system on Mg2+ regulation in the perfused rat heart and isolated myocytes. The Mg2+ content in the perfusate and supernatant were measured by atomic absorption spectrophotometer. The addition of membrane permeable cAMP analogue to the perfused hearts and myocytes. cAMP-induced Mg2+ efflux was ingibited by H7, benzamil or imipramine in the perfused hearts and myocytes, but not by EIPA. We confirmed that a significant Mg2+ efflux was induced by an increase in intracellular cAMP in the hearts and myocytes. The cAMP-induced increase of Mg2+ efflux in the hearts may be involved in ion transport system(Na+-Ca2+ and Na+-Mg2+ exchanger)

The present study was carried out to investigate the prevalence of mycoplasmal pneumonia of slaughter pigs in Youngnam area during the period from 1995 to 1997. The prevalence and pathomorphology of gross lung lesions were studied from 682 slaughter pigs in 8 swine herds. Gross lesions of pneumonia were recorede in the lungs of 442(64.8%), from 367 out of them(83.0%) were diagnosed as mycoplasmal pneumonia. Microbiological examination was performed with 197 lungs with gross lesions of mycoplasmal pneumonia of slaughter pigs from 8 differentswine herds. M hyopneumoniae, P multocida, A pleuropneumoniae, Streptococcus spp, Corynebacterium spp, and H parasuis were detected in 24.4%, 48.2%, 2.5%, 11.2%, 3.6%, and 1.0% of the pneumonic lungs, respectively. A total of 48 strains of M hyopneumoniae was investigated for thier in vitro susceptibility to antibiotics. Among the drugs tested, lincomycin, oxytetracycline, tiamulin and tylosin showed the high activity in minimal inhibitory concentration(MIC) of 0.04-5 micro gram/ml while erythromycin showed low activity in MIC values(1.25~40micro gram/ml).

Alpha toxin of S aureus has cytolytic activity respectively. This antigen has been received the most attention since it is a major virulence factor in pathogenesis of staphylococcal mastitis. Thus, alpha toxin has been focused as potential candidate ofvaccine tominimize mastitis in cows. the purpose of this study was to develop a simple, efficient production and purification methods of sufficient amount of alpha toxin antigen from S aureus. Alpha toxin production measured by hemolytic activity was the highest at 18 hrs postinoculation in yeast extract culture medium supplemented with thiamine, nicotinic acid and casamino acid. Alpha toxin was purifed by ammonium sulfate precipitation (65%) and ultrafiltration. Molecular weight of the toxin was 33 kDa in the analysis with SDS-PAGE. Conclusionally, when alpha toxin was included in the vaccine, the optimal harvest time of alpha toxin was at 18 hrs after inoculation in yeast extract medium supplemented with thiamine and nicotinic acid.

The development of uterus in fetuses on 60, 90 and 120 days of gastation and neonates of Korean native goats was investigated by scanning electron microscopy. The results were summarized as follows; 1. in the 60-day-old fetuses, the short microvilli were sporadically observed on the luminal surface of the endometrium. 2. In the 90-day-old fetuses, the mucosal folds, polygonal microridges, numerous microvilli, flower-like-buds, and domeshpaed or crateriform area were also observed on the luminal surface of endometrium. 3. In the 120-day-old fetuse, the primordial caruncles(nodules) of the endometrium were developed conspicuously and long microvilli were developed densely. 4. In the neonates, thecaruncles and microvilli of the endometrium were more developed than those of 120-day-old fetuses.

The morphological studies on the cecal development in the 60-, 90-, and 120-day-old fetuses and the newborns of Korean native goats were investigated by scanning and transmission electron microscopy. The results were summarized as follows; Scanning electron microscopic studies: 1. In the 60-day-old fetuses, fold-like shpaes protrusion oon the cecal mucosa surface appeared. In the 90-day-old fetuses, the cecal villi appeared to be columnar shpaes. In the 120-day-old fetuses, the cecal villi showed variou tongue-like or columnar shpaes. In the newborns, only the rudimental trace of the villi and the intestinal glands were observed. 2. In the 60-day-old fetuses, the cecal epithelia were simple columnar in some areas and stratified columnar in others, and the epithelial cells contained nuclei, nucleoli, ER, mitochondria, Golgi complexes, zonula occuludens, desmosomes, digitiform intercellular junctions, and large masses of the glycogen granules. 3. In the 90-day-old fetuses, the cecal epithelia were simple columnar in some area and stratified columnar in other. The microvilli of the cecal epithelia became much larger and longer than those in the 60-day-old fetuses, and intercellular junctions were developed, and increased numbers of ER, mitochondria, Golgi complexes were observed and the goblet cells contained a lot of the secretory granules. 4. In the 120-day-old fetuses, the cecal epithelia were only columnar in all areas. Microvilli and cytoplasmic organelles were well developed and the irregular annular nuclei were observed. 5. In the newborns, the cecal epithelia were covered with extensive microvilli, and the goblet cells with secretory granules were protruded into lumen. And some goblet cells secreted the secretory granules into the lumen.

In the present study we have analyzed the characteristics and distribution of the mu-opioid receptor(MOR) by raising anti-peptide antisera to the C-terminal peptide of MOR. The antisera against MOR was produced in New Zealand White rabbit against 15 residue corresponding to amino acids, 384-398of the cloned rat MOR. The antigenic peptide was synthesized using an Applied Biosystems 432 solid-phase peptide aynthesizer. The specificity and identification fo the antisera were tested by analysisi fo transfected cells, epitope mapping and immunohistochemical method. COS-7 cells electroporated with MOR cDNA were used to evaluate the characteristics and subcellular distribution of MOR.MOR immunoreactivity was prodominent in the plasmalemma and subcellular compartments such as encoplasmicreticulum, Golgi apparatus and vesicle like structure. Furthermore, both tissue sections and transfected cell lines could be immunostained with these antisera and the immunoreactivity ws abolished when anti-MOR sera were preincubated with the peptide against which they wer raised. Based on epitope mapping analysis, all antisera appeared to have a similar epitope, which ws detemined to be within the last amino acid,391-398. Moreover, immunohistochemistry showed that MOR immunoreactivity was ovserved in many brain areas including cerebral cortex, striatum, hippocampus, locus coeruleus and the superficial laminae of the dorsal horn. These stained spinal cord and brain aras showed themirrored pattern observed in autoradiographic studies of mu-opioid binding as well as a pattern similar to that seen by in situ hybridization for MOR. Thus, several lines of evidence support the conclusion that the antisera produced in the present study most likely recognize mu-opioid receptor. These results suggest that MOR antisera may be utilized as useful tool to analyze the physiological and pharmacological studies for mu-opioid receptor in the future