Morphometrical analysis of chicken Crytosporidium baileyi in various stages of life cycle in the bursa of Fabricius wer carried out by electron microscope to establish a differential point for identification of C baileyi. By avidin-biotin complex method, protozoans of the bursa of Favricius were identified Cryptosporidium spp. The size and area on each developmental stages of C baileyi, as measured by Morphomat 10 attached to electron microscope were as follews. Trophozoites' size with range of 3.21+_0.70*2.49+_0.59 micro meter, area with range of 118. 82+_41.92 micro meter2; meronts' size with 3.99+_1.07*2.96+_0.52 micro meter, area 210.11+_57.11 micro meter2 ; merozoites' size 1.98+_0.43*0.60+_0.18 micro meter, area 24.10+_5.97 micro meter2; microgametes' size 1.36+_0.83*0.50+_0.23 micro meter, area 20.23+_6.73 micro meter2; macrogametes'size 4.57+_0.65*4.02+_0.55 micro meter, area 258.37+_51.83 micro meter2; oocytes' size 4.39+_0.56*3.44+_0.50 micro meter, area 187.21 +_62.68 micro meter2. In conclusion, the size and area on each developmental stages of Cryptosporidium baileyi is different from that of other Cryptosporidia spp. It suggests, with considering tissue tropism and life cycle, morphometrical analysis can be quite a good way to identify C baileyi.

Anatomical and histological changes were studied in the dorsal, ventral, third and splenic lobes of the pancreas of the chicken embryos (8 days of incubation, 10 days of incubation to hatching). From 13 days of incubation, all four pancreatic lobes, namely, dorsal, ventral, third and splenic lobes were observed. Histologically, the pancreas of 10-14 days of incubation were consisted of mesenchymal tissue, exocrine acini and pancreatic islets. But mesenchymal tissues were disappeared from 15 days of incubation. The pancreatic ducts were observed from 14 days of incubation. The dark and light typed pancreatic islets were observed in splenic lobe from 13 days of incubation, in the third lobe from 11 days of incubation, and in the dorsall lobe from 13 days of incubation. But no dark typed islets were observed in the ventral lobes.

To investigate the effect of the environmental pollutants, polycyclic aromatic hydrocarbons (PAHs), on retinoic acid-induced teratogenesis, all-trans-retinoic acid (RA) dissolved in corn oil (120 mg/kg) was administered orally to pregnant rats at the 11th day of gestation with and without the prior intraperitoneal treatment with 10 mg/kg 3-methylcholanthrene (3-MC) for 3 days. Dams were killed on the 20th day of pregnancy. The examinations of fetuses revealed that 3-MC barely enough to cause induction of P-450 in pregnant dams had profound embryo-toxic effects: the fetal resorption amounted to - 60% of total number of implantations. The fetuses survived weighed less than the control fetuses. All of RA-treated mothers had fetuses with abnormalities, and the main malformations were absence of tail (100%), caudal and sacral malformations (100%), and cleft palate (42%). Pregnant dams received both 3-MC and RA had a reduced severeness of tail anomaly (33%), while the rest, 67%, had short vestigial tail. Caudal and sacral malformations were detected but at a milder degree. We did not observe cleft palate in this group. The concurrent treatment of dams with 3-MC and RA led to an increased inducibility of cytochrome P-450 and subsequently, CYP1A1 dependent enzyme activity higher than those observed after the injection of 3-MC alone. UDP-glucuronyltransferase activity was also markedly induced in concurrent 3-MC and RA group higher than that in 3-MC alone. We suggest that the induction of P-450 and alteration of metabolic enzyme activities may play an important role in reducing the teratogenic potency of RA. However, RA-treatment did not retard the embryo-toxic effect of 3-MC but rather potentiated

Intranasal administration of plasmid DNA encoding glycoprotein B of pseudorabies virus into mice induced both serum and secretory antibody responses. These mice resisted intranasal challenge with lethal dose of the virus, but did not intraperitoneal challenge. On the other hand, intramuscular injection of the plasmid induced less secretory and higher serum antibody responses than those of intranasally vaccinated mice. None of them was protected from virus challenge. The present results suggest that administration of plasmid DNA encoding glycoprotein B by respiratory mucosal route generates local secretory antibodies which serve to protect animals from pseudorabies virus infection

The proteolytic activities present in midguts of both fed and unfed Haemaphysalis longicornis were assessed by using the gelatin-substrate gel electrophoresis and inhibitor sensitivity analyses. Three predominant (116, 48 and 40 kDa) and two weak (55 and 60 kDa) proteinase bands were commonly expressed in both unfed and fed ticks, while a weak 80 kDa band was only present in fed ticks. Consistent with observations on other tick species, proteolytic activity against the gelatin substrate was observed only under acidic conditions. Inhibition studies against the gelatin substrate using a panel of inhibitors showed that the predominant proteolytic enzymes of 40 and 48 kDa molecular mass are cysteine proteinases. These results are discussed in the context of host vaccination as an alternative tick control method to the current use of chemical acaricides

There are few copies of Borna disease virus (BDV) genome in peripheral blood mononuclear cells and no reliable standard reverse transcriptase-polymerase chain reaction (RT-PCR) method for the detection of BDV RNA, which is both highly sensitive and free of contamination. Single-step RT-PCR, in which both reverse transcription and amplification by Taq DNA polymerase work efficiently in a single buffer, was applied to detect the p24 region of BDV RNA in vitro and in vivo. Using in vitro synthesized RNA, it was demonstrated that at least 100 copies of BDV RNA could be detected and the sensitivity and specificity were nearly equal to those obtained by RT-nested PCR. We could detect BDV RNA from more than 1 pg of cellular RNA obtained from BDV-persistently infected MDCK cells. Furthermore, this method was successfully performed on brain specimens obtained from a BDV-infected rat at 11 weeks post-inoculation. This single-step RT-PCR method will be convenient for detecting limited amounts of BDV RNA in various cells and tissue samples

The validity of a coproantigen ELISA for Echinococcus multilocularis was evaluated by comparison of three diagnostic methods; autopsy, egg examination and the ELISA. Of 71 foxes, 39 were found to be infected with the cestode at autopsy. The overall mean of worm burdens was 3,451, but the number varied (1-34,522). The ELISA could detect 94.9% (37/39) of the worm positives and there were no false-positives. Two false-negatives were infected with 1 and 4 cestodes, whereas 3 cases with similar worm burdens (2, 4 and 6 worms) were diagnosed as positives. This indicates the detection limit of the assay may be equivalent to less than 10 (in the worm burden). On the other hand, egg examination showed low sensitivity (43.6%, 17/39). These results suggest the ELISA has a potential to replace for the conventional methods

Substance P (SP) is colocalized with ACh in splanchnic nerves that innervate into adrenal medulla and the peptide has been shown to inhibit nicotinic agonists-induced catecholamine secretion. To elucidate the effects of SP on cytosolic Ca(2+) dynamics, the present study was conducted using fura-2-loaded isolated bovine adrenal chromaffin cells. Stimulation of the cells with nicotine (10-100mu-M) produced a rapid rise of cytosolic Ca(2+) concentration ([Ca(2+)]i), the peak level of which increased in a dose-dependent manner, followed by a gradual decay. In the presence of 10mu-M SP, the dose-response relationship of the peak levels shifted downward. Quantitative analyses implied that SP inhibits the nicotine-induced Ca(2+) influx in a noncompetitive manner. Nicotinic acetylcholine receptor is composed of two major functional domains: an agonist-binding site and an ionophore or channel domain. Agonist binding activates ionophore / channel domain and causes mainly Na(+) influx. This Na(+) influx depolarizes the cell and activates voltage-dependent Ca(2+) channels. Based on this fact, the present results indicate that SP dose not block nicotine binding sites but interferes with other sites of nicotinic receptor / channel molecule, most probably a channel domain. It was suggested that SP colocalized with ACh in splanchnic nerves functions as a physiological modulator of catecholamine secretion by non-competitively suppressing ACh-induced cytosolic Ca(2+) dynamics in bovine a

The hemagglutinin (HA) of six H5 influenza virus strains isolated from ducks in Japan and China in 1976 to 1996 were analyzed antigenically and genetically. Antigenic analysis using a panel of monoclonal antibodies revealed that the HA of H5 influenza viruses isolated from ducks are antigenically closely related to each other. Phylogenetic analysis indicates that the isolates from ducks in Hokkaido were derived from an ancestor common with the highly pathogenic isolates from chickens and human