Morphological features of the testicular artery and vein in the spermatic cord of the musk shrew (Suncus murinus) were evaluated by light microscopy, transmission electron microscopy, corrosion cast technique combined with scanning electron microscopy and immunohistochemistry. The vascular architecture in the spermatic cord of the musk shrew was simple. The testicular artery in the musk shrew was straight and accompanied by 1 to 3 branches of testicular vein. The testicular vein was also straight and anastomosed with each other in some points along its length, but it did not form a delicate pampiniform plexus. In the middle and distal portions of the spermatic cord, the tunica adventitia of the artery and vein was joined together to form a single connective tissue septum. Clusters of cells were found in this connective tissue septum in the middle portion of the cord. These cells were located close to the arterial wall and nerve endings, but they did not appear inside of neurium. They showed several typical characteristics similar to Leydig cells, and they were positive for 3β hydroxysteroid dehydrogenase (HSD) antibody. Ultrastructural and immunohistochemical studies also indicated that the cells in cluster found in the vascular wall of the musk shrew spermatic cord may be equivalent to Leydig cells in testes. These extratesticular Leydig cells had characteristics of the active steroid-producing cell and seemed to be another source of testosterone.

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This study was carried out to determine the proliferation profile of the smooth muscle cells (SMC) in the media of the ductus arteriosus (DA) and the descending aorta (Ao), and to examine the effects of the angiotensin-converting enzyme inhibitor enalapril on the proliferation of these cells in perinatal rats. The proliferating cell nuclear antigen (PCNA) index of the DA peaked in 19-day-old fetuses at 75%, and the index significantly declined in 20-day-old fetuses. The PCNA index of the Ao showed a similar profile until pups reached 1 day of age; however, the index of the Ao then increased in 3-day-old pups. The PCNA indices of the DA and Ao decreased significantly after maternal oral treatment with enalapril (10 mg/kg for 7 days), with a more marked decline in the DA than in the Ao. The PCNA indices of these vessels in 20-day-old fetuses were not altered by maternal treatment with enalapril. These results indicate that the SMC proliferation rate in the DA was similar to that in the Ao until pups reached the age of 1 day, and that the inhibitory effect of enalapril on the SMC proliferation was age-dependent and more prominent in the DA than in the Ao.

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Quantitative changes of lung tissue components (air spaces lined by PAS-positive and PAS-negative epithelium, blood vessels and interstitium) were investigated in developing rats from fetal day 18 through neonatal day 1. The volume of the left lung increased significantly from fetal day 18 through neonatal day 1. The percentage and volume of the air spaces increased strikingly between fetal days 20 and 21. However, the percentage of the air spaces lined by PAS-positive epithelium decreased significantly from fetal days 20 to 21, and that of the spaces lined by PAS-negative epithelium increased between the two days. The proliferating cell nuclear antigen (PCNA)-positive cells were rich in the interstitium and epithelium of the air spaces on fetal days 18 and 19. The percentage of the interstitium decreased significantly from fetal day 18 through neonatal day 1, showing remarkable decrease between fetal days 20 and 21. From fetal day 20 onward, the PCNA-positive cells decreased in number and located in the epithelium of the conducting air ways and interstitium. Based upon these findings, the present study suggests that the period from fetal days 20 to 21 is a critical time for the development of fetal lung: the period before fetal day 20 is that for proliferation and the period after fetal day 21, functional differentiation of the lung.

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To provide information on the epidemiology of Newcastle disease (ND) of poultry in Taiwan, ND virus isolates from chickens and an owl were investigated by restriction site analysis and sequencing of their gene. A 1, 349 base fragment of the F (fusion protein) gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR). The PCR products were analyzed using restriction endonucleases, HinfI, BstOI, and RsaI. Three strains isolated from chickens during the 1995 epidemic outbreak had the same restriction sites as that of a 1994 isolate; the number of the restriction sites of HinfI, BstOI, and RsaI were 4, 2, and 4, respectively. In the F gene of the strain isolated from an owl during the same outbreak an additional restriction site of HinfI was found. The 1991 isolate had only 3 restriction sites. The F gene of the owl isolate was amplified by RT-PCR and followed by direct sequencing. The deduced amino acid sequence at the cleavage site of the F protein was of virulent strains, ¹¹²R-R-Q-K-R-F¹¹⁷. The F gene of Ow/Tw/2209/95 was phylogenetically most closely related to that of Ck/Tw/2137/95 isolated from the same outbreak. The present results indicate that the causative virus of the 1995 ND outbreak had already been present in Taiwan.

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The production and role of endogenous cytokines during the course of secondary Corynebacterium (C.) pseudotuberculosis infection were investigated in mice. When immunized mice were challenged on day 28 after primary infection, tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) were found to appear at 3 hr and to reach the maximum at 24 hr after challenge. Spleen cells of mice primarily infected from 2 to 8 weeks before produced a significant amount of TNF-α and IFN-γ when stimulated with formalin-killed bacteria. However, they could not produce detectable amounts of IL-4. The administration of anti-TNF-α monoclonal antibody (MAb) and IFN-γ MAb increased bacterial proliferation in the organs of immune mice and exacerbated the secondary infection. Injection of anti-CD4 MAb alone or anti-CD4 plus anti-CD8 MAbs resulted in significantly increased mortality and a marked suppression of bacterial elimination as well as cytokine production of secondarily infected mice, while the treatment with anti-CD8 MAb alone showed no effect on either the resistance or cytokine production of mice. These results suggest that CD4, probably Th1 T cells, play an important role for establishment of protective immunity against secondary C. pseudotuberculosis infection by secreting TNF-α and IFN-γ

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Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a CD28 homologue which down-modulate T cell responses rather than augment them. To investigate its biological role in feline immune system, we cloned and sequenced full-length feline CTLA-4 (fCTLA-4) cDNA by RT-PCR from pokeweed mitogen stimulated peripheral blood lymphocytes. The fCTLA-4 contains an open reading frame of 669 nucleotides, coding for a polypeptide of 223 amino acids. The predicted fCTLA-4 amino acids sequence shows the homology of 86.6%, 87.0%, and 76.2% with human, bovine, and murine molecules respectively. The hexapeptide motif (MYPPPY) within the extra-cellular domain of CTLA-4 molecule, which is believed to be responsible for interaction with the B7 family members, is completely conserved in all the species.

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Effects of recombinant bovine granulocyte-macrophage colony-stimulating factor (rboGM-CSF) on bactericidal activity of bovine peripheral blood neutrophils in vitro and in vivo were studied. In in vitro experiment, bovine blood neutrophils were cultured for 9 hr in media containing 0.005, 0.05 or 0.5 μg/ml of rboGM-CSF. Neutrophils treated with rboGM-CSF showed significantly higher luminol-dependent chemiluminescence (LDCL) than control cells. In in vivo experiment, neutrophils isolated from cows injected 5.0 μg/kg of rboGM-CSF showed significantly higher Nitrobluetetrazolium (NBT) reduction value than that from control cows 24 hr post injection. Total leukocyte counts of cows injected rboGM-CSF sharply decreased 6 hr post injection and recovered to normal level 2 days post injection. Body temperature of these cows rose 6 hr post injection and back to normal level at 24 hr post injection. It was suggested that rboGM-CSF enhanced bactericidal activity of bovine neutrophils both in vitro and in vivo.

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We conducted protein loading to examine the progression and pathogenesis of diabetic nephropathy. For this experiment, male OLETF, LETO, F344 and BN rats were used. This experiment was performed on rats between 5 and 30 weeks of age. Examination parameters included body weight, food intake, oral glucose tolerance test (OGTT), urinary protein level (UP), urinary albumin level (UA), glomerular filtration rate (GFR), kidney weights, light microscopy (LM) and electron microscopy (EM). In the protein-loaded OLETF group, the UP level was markedly increased 20 weeks or more after birth. In OLETF control group, GFR were higher than those in other strains. Glomerular hypertrophy and kidney weights were markedly increased in protein-loaded groups in OLETF rats. Thirty weeks after birth, EM showed that the number of polyethyleneimine (PEI) of the glomerular basement membrane (GBM) in protein-loaded OLETF group was significantly decreased compared to that in control group. These changes in OLETF rats were more marked in the protein-loaded group than those in the control group. LM showed that the number of exudative lesions with fibrin-cap in the protein-loaded OLETF group was significantly increased than those in control group. In OLETF rats, protein loading caused deterioration of nephropathy at 30 weeks of age. Therefore, it was demonstrated that not only blood sugar control but also protein intake factors play important roles in the deterioration of nephropathy in OLETF rats.

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The Long-Evans Cinnamon (LEC) mutant rat shows higher incidence of renal cell carcinomas induced by a treatment with the chemical carcinogen N-diethylnitrosamine, as compared to the normal control rat. We performed the first genome-wide scan for genes responsible for susceptibility to chemically induced renal cell carcinoma in an F₂ intercross obtained by mating the LEC and Fischer-344 (F344) rats. The genotype of 71 (F344 × LEC) F₂ progenies was determined with the use of 338 simple sequence length polymorphisms (SSLPs) spread over the genome. The F₂ rats which carried renal cell carcinoma were shown to possess the incidence of homozygosity of the LEC allele which is higher than that of the other genotypes at SSLP markers on chromosome 5 (χ² = 17.5 for D5Rat21). Our linkage analysis has led to the revelation of a novel gene that influences susceptibility to renal cell carcinoma on rat chromosome 5.

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The gene encoding Toxoplasma gondii P24 has been reported previously. To determine the function of P24 against immune systems in the near future, we prepared recombinant P24 antigens using Escherichia coli, insect cells infected with recombinant baculovirus and mammalian cells infected with recombinant vaccinia virus. The P24 antigens derived from E. coli, insect cells and mammalian cells were detected with mouse immune sera against P24 or T. gondii homogenates by Western blot analysis; these corresponded to the authentic P24 and secreted into the supernatants of the insect and mammalian cell cultures. These proteins were not effected by tunicamycin treatment in cultured cells, indicating that recombinant P24 did not contain N-linked sugars. Recombinant P24 was separated by two-dimensional electrophoresis and analyzed by Western blotting. From these results, P24 was acidic protein and had identical isoelectric point with the authentic P24.

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Bacillus amyloliquefaciens DS11 phytase (DS11 phytase) and Aspergillus ficuum phytase (AF phytase) activities were investigated by measuring the release of phosphate from phytate in animal feedstuff such as wheat bran, corn meal, soybean meal and rice flour at pH 5 and 7. In all the tested feedstuff, the enzymatic activity of DS11 phytase was more active at pH 7, but that of AF phytase was more active at pH 5. From these results, the phytate in the gastrointestinal tract could be degraded in the small intestine or stomach by DS11 or AF phytase, respectively. In conclusion, the results presented in this paper indicated that different combination ratios of DS11 and AF phytase, depending on the kind of feedstuff, might effectively induce more enzymatic activity both in the stomach and small intestine in terms of the pH of the gastrointestinal tract.

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We examined the effect of glucocorticoids on brush border membrane transporters and, furthermore, the involvement of Ca²⁺ in its action in the primary cultured rabbit renal proximal tubule cells (PTCs). Dexamethasone (DEX, 10^-9 M) decreased Pi uptake by 17%; whereas DEX affected neither α-methyl-glucopyranoside (α-MG) uptake nor Na⁺ uptake. The DEX-induced inhibition of Pi uptake was due to a decrease of V_max. In contrast, other steroid hormones such as progesterone, testosterone, and 17β-estradiol (10^-9 M) did not induce inhibition of Pi uptake. In order to examine the involvement of Ca²⁺ in DEX-induced inhibition of Pi uptake, PTCs were treated with A 23187 (10^-6 M, Ca²⁺ ionophore). A 23187 also inhibited Pi uptake, mimicking DEX action in Pi uptake. Treatments with W-7 (10^-4 M, calmodulin dependent kinase inhibitor), KN-62 (10^-6 M, Ca²⁺/calmodulin-dependent protein kinase II inhibitor), and BAPTA/AM (10^-6 M) or TMB-8 (10^-4 M) (intracellular Ca²⁺ mobilization blockers) blocked the DEX-induced inhibition of Pi uptake. However, nifedifine, methoxyverapamil (10^-6 M, L-type Ca²⁺ channel blockers), and EGTA (1 mM, extracellular Ca²⁺ chelator) did not block it. In conclusion, DEX inhibited Pi uptake via, in part, Ca²⁺/calmodulin pathway mediated by intracellular Ca²⁺ mobilization in the PTCs.

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We established the PCR detection system specific to Salmonella species using Salmonella enterotoxin gene (stn). The detection limit was one bacterial cell per one gram of fecal and minced-meat samples using enrichment procedure by Tripticase soy broth or Salmonella enrichment broth, respectively. We concluded that this PCR system is useful for the practical application in the field of the public hygiene.

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We used a consensus primer PCR method to amplify a region of herpesviral DNA-directed DNA polymerase gene using degenerate primers for initial characterization of the porcine cytomegalovirus (PCMV) genome. The sequence of the PCR product from PCMV DNA template and its alignment with other herpesvirus DNA polymerase counterparts showed that both conserved amino acid residues and conservative amino acid substitutions are in parallel. Phylogenetic analysis revealed that PCMV should be included in the clade comprising human herpesvirus 6 and 7, rather than human and mouse cytomegaloviruses, in Betaherpesvirus subfamily.

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