Effect of tissue deterioration on postmortem BSE diagnosis by immunobiochemical detection of an abnormal isoform of prion protein

Surveillance for bovine spongiform encephalopathy (BSE) in fallen stock in Japan is conducted with a commercial enzyme-linked immunosorbent assay (ELISA) for mass screening, with Western blotting (WB) and immunohistochemistry performed for confirmation of the ELISA. All tests are based on immunological detection of an abnormal isoform of the prion protein (PrP(Sc)) in brain tissues, which have sometimes deteriorated by the time samples from fallen stock reach a diagnostic laboratory. To evaluate BSE surveillance procedures for fallen stock, we examined PrP(Sc) detection from artificially deteriorated BSE-affected bovine brain tissues with a commercial ELISA kit and compared the results with those of WB. The optical density (OD) values of the ELISA decreased with advancing deterioration of the tissues, whereas no reduction in the signal for PrP(Sc) was observed in WB, even when performed after 4 days of incubation at 37 degrees C. The progressive decrease in the OD values in the ELISA appear to be caused by a partial loss of the N-terminal moiety of PrP(Sc) due to digestion by endogeneous and/or contaminated microbial enzymes, and by the presence of ELISA inhibitors that are generated in deteriorated tissues. These results suggest that WB is the most reliable test for fallen stock, especially for cattle brains within decaying carcasses.     

The antiproliferative effect of bovine lactoferrin on canine mammary gland tumor cells

Lactoferrin has several biological activities, including antitumor activities in some human and animal tumor cells. Clinical trials have been carried out in human medicine based on these effects. However, the antitumor effects of lactoferrin in veterinary medicine remain unknown. In this in vitro study, we demonstrated that co-incubation of canine mammary gland tumor cells (CIPp and CHMp) and bovine lactoferrin induced growth arrest of tumor cells. This growth arrest was associated with induction of G1 arrest. Furthermore, this effect was stronger in tumor cells than in normal cells. These findings demonstrate that bovine lactoferrin has anti-tumor activity in canine mammary tumors and has the potential for use in tumor-bearing dogs.     

Biological activity of recombinant bovine interferon tau using an Autographa californica nuclear polyhedrosis virus expression system

Bovine interferon (bIFN) tau, which plays a key role in maternal-fetal recognition of pregnancy, was expressed by an Autographa californica nuclear polyhedrosis virus expression system. cDNA coding bIFNtau was derived from cultured trophoblast cells. The recombinant (r) bIFNtau had high antiviral activity (1 x 10 (8) IU/mg) and the molecular weight of rbIFNtau was estimated to be 23 kDa by Western blotting analysis. We investigated the biological effect of rbIFNtau on prostaglandin (PG) F(2alpha) synthesis in cultured bovine endometrial epithelial cells in the presence or absence of oxytocin (OT, 100 nM). rbIFNtau suppressed basal and OT-induced PGF(2alpha) production in a dose-dependent manner (1-1,000 ng/ml). These results showed that biologically active rbIFNtau was produced in the baculovirus expression system, and that rbIFNtau had the ability to suppress the synthesis of PGF(2alpha) from bovine endometrial epithelial cells.     

Susceptibility to N-methyl-N-nitrosourea-induced retinal degeneration in different rat strains

To evaluate the potential role of genetic background in the susceptibility to retinal degeneration induced by N-methyl-N-nitrosourea (MNU), female rats of the Sprague-Dawley (SD), Long-Evans (LE) and Copenhagen (CH) strains were administered 50 mg/kg MNU or saline at 7 weeks of age. Retina morphology and morphometric analysis of all rats was performed 7 days after MNU administration. Atrophy of both the peripheral and central outer retina occurred in all rat strains exposed to MNU. Decreased photoreceptor cell ratio and increased retinal damage ratio were observed. The severities of the retinal atrophy were similar among all three rat strains. In conclusion, MNU-induced photoreceptor degeneration developed consistently in all three strains regardless of the absence (SD rats) or presence (LE and CH rats) of melanin in the retina, suggesting that genetic and melanin factors did not affect photoreceptor cell death after MNU.     

Assessment of the measurement of canine and feline serum fibroblast growth factor-23 concentrations by automated chemiluminescence immunoassay

This study compared canine and feline fibroblast growth factor (FGF)-23 concentration measurements between automated chemiluminescence assay (CLEIA) and enzyme-linked immunosorbent assay (ELISA). Seventy serum samples each from dogs and cats were evaluated. FGF-23 measurements by CLEIA significantly correlated with those of ELISA in both dogs and cats. The Bland–Altman test showed that FGF-23 between CLEIA and ELISA had fixed and proportional biases, respectively, in both dogs and cats. Measurements by CLEIA were lower than those of ELISA, especially in higher serum FGF-23 concentrations. This study showed that FGF-23 concentrations in dogs and cats can be evaluated by automated CLEIA. However, FGF-23 cannot be directly compared between CLEIA and ELISA.     

In vitro and in vivo effects of recombinant bovine interferon-tau on bovine leukemia virus

The antiviral effects of recombinant bovine interferon-tau (rboIFN-tau) on bovine leukemia virus (BLV) were examined in vitro and in vivo. In the in vitro experiments, BLV titers decreased in FLK-BLV cells and in peripheral blood mononuclear cells of BLV-infected cattle treated with rboIFN-tau at a concentration higher than 10(2) U/ml. In order to examine the in vivo effects of rboIFN-tau, 10 BLV-infected cattle were subcutaneously injected with rboIFN-tau. In the first experiment, 6 cows were administrated with 10(5) U/kg body weight of rboIFN-tau 3 times per week for 4 weeks, while in the second experiment 4 cows were administrated with 10(6) U/kg body weight of rboIFN-tau 3 times per week for 3 weeks. No adverse effects were observed after the administration of rboIFN-tau. In experiment No. 1, the mean BLV titers in cattle decreased in the post-rboIFN-tau administration period compared to the pre-rboIFN-tau administration period. In experiment No. 2, the mean BLV titers in cattle decreased in the rboIFN-tau administration period. These results suggest that rboIFN-tau decreases BLV titers in vitro and in vivo and that rboIFN-tau possibly reduces the degree of BLV titer in cattle without severe side effects.     

Neuroanatomical distribution of disease-associated prion protein in cases of bovine spongiform encephalopathy detected by fallen stock surveillance in Japan

Bovine spongiform encephalopathy (BSE) is a fatal neurodegenerative disorder of cattle characterized by accumulation of the disease-associated prion protein (PrP(Sc)) in the central nervous system (CNS). The immunohistochemical patterns and distribution of PrP(Sc) were investigated in the CNS, brains, and spinal cords of 7 naturally occurring BSE cases confirmed by the fallen stock surveillance program in Japan. No animals showed characteristic clinical signs of the disease. Coronal slices of 14 different brain areas in each case were immunohistochemically analyzed using an anti-prion protein antibody. Immunolabeled PrP(Sc) deposition was widely observed throughout each brain and spinal cord. Intense PrP(Sc) deposition was greater in the thalamus, brainstem, and spinal cord of the gray matter than in the neocortices. The topographical distribution pattern and severity of PrP(Sc) accumulation were mapped and plotted as immunohistochemical profiles of the different brain areas along the caudal-rostral axis of the brain. The distribution pattern and severity of the immunolabeled PrP(Sc) in the CNS were almost the same among the 7 cases analyzed, suggesting that the naturally occurring cases in this study were at the preclinical stage of the disease. Immunohistochemical mapping of the PrP(Sc) deposits will be used to clarify the different stages of BSE in cattle.     

Control of Pseudomonas mastitis on a large dairy farm by using slightly acidic electrolyzed water

The disinfection effect of slightly acidic electrolyzed water (SAEW) use in a farm where Pseudomonas mastitis has spread was evaluated. Despite the application of antibiotic therapy and complete cessation of milking infected quarters, numerous new and recurrent Pseudomonas aeruginosa clinical mastitis infections (5.8–7.1% of clinical mastitis cases) occurred on the farm from 2003 to 2005. Procedural changes and equipment modifications did not improve environmental contamination or the incidence of Pseudomonas mastitis. To more thoroughly decontaminate the milking parlor, an SAEW system was installed in 2006. All milking equipment and the parlor environment were sterilized with SAEW (pH 5–6.5, available chlorine 12 parts per million) before and during milking time. After adopting the SAEW system, the incidence of clinical and subclinical Pseudomonas mastitis cases decreased significantly (P < 0.0001) and disappeared. These findings suggest that SAEW effectively reduced the incidence of mastitis in a herd contaminated by Pseudomonas species. This is the first report to demonstrate the effectiveness of disinfection by SAEW against mastitis pathogens in the environment.