Search

Eight crossbred steers (BW 719.0 ± 65.0 kg) with ruminal and duodenal cannulae were used to examine the effect of trace mineral (TM) source on digestibility; ruminal and duodenal solubility of Cu, Zn, and Mn; and in vitro release of Cu, Zn, and Mn from the solid fraction of ruminal digesta. Experiment 1 determined the effect of TM source on DM and NDF digestibility in steers fed a corn silage and steam-flaked corn-based diet. Treatments consisted of 10 mg Cu, 20 mg Mn, and 30 mg Zn/kg DM from either sulfate TM (STM) or hydroxy TM (HTM) sources. Following a 14-d adaptation period, total fecal output was collected for 5 d. Dry matter digestibility was not affected by treatment, but NDF digestibility tended (P < 0.09) to be greater in HTM vs. STM supplemented steers. In Exp. 2, steers were fed a diet without supplemental Cu, Zn, or Mn for 19 d. Steers were then administrated a pulse dose of STM or HTM (2× the National Research Council requirements for Cu, Mn, and Zn) via the rumen fistula. Ruminal and duodenal samples were obtained at 2-h intervals starting at −4 and ending at 24 h relative to dosing. Ruminal soluble Cu and Zn concentrations were affected by treatment, time, and treatment × time. Soluble concentrations and percent soluble Cu and Zn in ruminal digesta increased (P < 0.05) above 0-h values for 10 h following dosing with STM, but not HTM. Concentrations of Cu and Zn in ruminal solid digesta were also affected by treatment, time, and treatment × time. Steers dosed with STM had greater (P < 0.05) solid digesta Cu concentrations at 2 and 4 h but lesser (P < 0.05) concentrations from 6 to 20 h post-dosing than those receiving HTM. Ruminal solid digesta Zn concentrations were greater (P < 0.05) in HTM vs. STM-dosed steers from 6 through 24 h post-dosing. Distribution of Mn in ruminal digesta was affected by TM source, but to a lesser extent than Zn and Cu. Duodenal soluble TM concentrations were variable and not affected by treatment. Binding strength of TM to ruminal solid digesta was estimated at 0, 6, and 12 h post-dosing using dialysis against chelating agents. The percentage of Cu and Zn released from ruminal solid digesta by dialysis against Tris–EDTA was greater (P < 0.05) at 12 h post-dosing from steers receiving HTM vs. STM. Results indicate that Cu and Zn from HTM have low solubility in the rumen and appear to be less tightly bound to ruminal solid digesta than Cu and Zn from STM. [ABSTRACT FROM AUTHOR]

Abstract: Gene delivery by intravenous injection of cationic liposome–DNA complexes (LDC) can generate efficient transgene expression in the lungs and other organs, but the duration of expression is typically short. Previous studies have suggested a major role for interferon-γ (IFN-γ) and TNF in this process. However, plasmid DNA is also capable of eliciting production of type I IFNs. Therefore, we assessed the ability of LDC to elicit production of type I IFNs in vivo and assessed the effects of type I IFNs on suppression of transgene expression following in vivo gene delivery with LDC. Injection of LDC was found to induce production of high levels of both IFN-α and IFN-β in vivo. Moreover, the levels of transgene expression following in vivo gene delivery were markedly increased in mice lacking functional type I IFN receptor genes, compared to wild-type mice or mice lacking IFN-γ or TNF receptors. Addition of recombinant IFN-α and IFN-β inhibited transgene expression by in vitro-transfected endothelial cells, and incubation of macrophages with LDC in vitro triggered production of both IFN-α and IFN-β. Therefore, type I IFNs appear to play a key role in suppressing transgene expression in vivo following systemic nonviral gene delivery using LDC. [Copyright &y& Elsevier]

The purpose of this study was to evaluate the effect of successful treatment for Bartonella spp, Mycoplasma hemofelis or Candidatus Mycoplasma haemominutum infection of cats on results of diagnostic test results commonly available to veterinary practitioners through commercial diagnostic laboratories. Evidence of infection or exposure to Bartonella spp, M hemofelis or Candidatus M. haemominutum was detected in 15 cats with fever. Doxycycline (50 mg) or orbifloxacin (22.7 mg) were administered empirically by mouth for 28 days to 12 cats with laboratory evidence of Bartonella spp infection alone and three cats with laboratory evidence of Bartonella spp and M. hemofelis or Candidatus M. haemominutum co-infection with the laboratory tests repeated on Day 35 and 58 (10 cats) or Day 35 alone (5 cats). While clinical illness in all 15 cats rapidly resolved, all nine cats that were PCR positive for Bartonella spp on Day 0 were still PCR positive on Day 35. Four of the six cats tested on Day 58 were still positive. Only one cat that was positive for Bartonella spp antibodies detected by ELISA on Day 0 was negative on Day 35 and Day 58. Of the 3 cats that were PCR positive for M. hemofelis or 'Candidatus M. haemominutum' on Day 0, only 1 cat (Candidatus M. haemominutum' was PCR positive on Day 35 or Day 58. The results of the study support the recommendation that cats with suspected clinical bartonellosis should be evaluated concurrently by PCR (or culture) and serology. There appears to be little indication for following Bartonella spp assay results within the first 30 days using the treatment protocols described herein. [ABSTRACT FROM AUTHOR]

Eight crossbred steers (BW 719.0 ± 65.0 kg) with ruminal and duodenal cannulae were used to examine the effect of trace mineral (TM) source on digestibility; ruminal and duodenal solubility of Cu, Zn, and Mn; and in vitro release of Cu, Zn, and Mn from the solid fraction of ruminal digesta. Experiment 1 determined the effect of TM source on DM and NDF digestibility in steers fed a corn silage and steam-flaked corn-based diet. Treatments consisted of 10 mg Cu, 20 mg Mn, and 30 mg Zn/kg DM from either sulfate TM (STM) or hydroxy TM (HTM) sources. Following a 14-d adaptation period, total fecal output was collected for 5 d. Dry matter digestibility was not affected by treatment, but NDF digestibility tended (P < 0.09) to be greater in HTM vs. STM supplemented steers. In Exp. 2, steers were fed a diet without supplemental Cu, Zn, or Mn for 19 d. Steers were then administrated a pulse dose of STM or HTM (2× the National Research Council requirements for Cu, Mn, and Zn) via the rumen fistula. Ruminal and duodenal samples were obtained at 2-h intervals starting at −4 and ending at 24 h relative to dosing. Ruminal soluble Cu and Zn concentrations were affected by treatment, time, and treatment × time. Soluble concentrations and percent soluble Cu and Zn in ruminal digesta increased (P < 0.05) above 0-h values for 10 h following dosing with STM, but not HTM. Concentrations of Cu and Zn in ruminal solid digesta were also affected by treatment, time, and treatment × time. Steers dosed with STM had greater (P < 0.05) solid digesta Cu concentrations at 2 and 4 h but lesser (P < 0.05) concentrations from 6 to 20 h post-dosing than those receiving HTM. Ruminal solid digesta Zn concentrations were greater (P < 0.05) in HTM vs. STM-dosed steers from 6 through 24 h post-dosing. Distribution of Mn in ruminal digesta was affected by TM source, but to a lesser extent than Zn and Cu. Duodenal soluble TM concentrations were variable and not affected by treatment. Binding strength of TM to ruminal solid digesta was estimated at 0, 6, and 12 h post-dosing using dialysis against chelating agents. The percentage of Cu and Zn released from ruminal solid digesta by dialysis against Tris–EDTA was greater (P < 0.05) at 12 h post-dosing from steers receiving HTM vs. STM. Results indicate that Cu and Zn from HTM have low solubility in the rumen and appear to be less tightly bound to ruminal solid digesta than Cu and Zn from STM. [ABSTRACT FROM AUTHOR]

IFN-alpha has been shown to induce both antiviral and antiproliferative activities in animals. This report describes the biological activity of five recently identified feline IFN-alpha subtypes expressed in the Chinese hamster ovary (CHO) cell line (rfeIFN-alpha1[CHO], rfeIFN-alpha2[CHO], rfeIFN-alpha3[CHO], rfeIFN-alpha5[CHO] and rfeIFN-alpha6[CHO]) and the feIFN-alpha6 subtype expressed in and purified from Pichia pastoris (rfeIFN-alpha6[P. pastoris]). The rfeIFN-alpha[CHO] subtypes were tested for antiviral activity against either Vesicular stomatitis virus (VSV) or feline calicivirus (FCV) infected feline embryonic fibroblast cell line (AH927) or Crandell feline kidney cell line (CRFK). Antiviral activity was induced against both VSV and FCV infected AH927 cells and VSV infected CRFK cells by all five of the rfeIFN-alpha[CHO] subtypes and rfeIFN-alpha6[P. pastoris]. In addition, the IFN-alpha inducible Mx gene (associated with antiviral activity) was upregulated in vivo 24 h following treatment with rfeIFN-alpha6[P. pastoris], compared to baseline levels seen prior to treatment. All of the rfeIFN-alpha[CHO] subtypes and rfeIFN-alpha6[P. pastoris] exhibited antiproliferative activity in the FeT-J cell line (an IL-2 independent feline T-cell line). Both necrosis and apoptosis were observed in rfeIFN-alpha6[P. pastoris]-treated FeT-J cells. The rfeIFN-alpha3[CHO] subtype consistently exhibited lower antiviral and antiproliferative activity compared to that observed with the other four rfeIFN-alpha[CHO] subtypes. In summary, this paper demonstrates that five previously described feIFN-alpha subtypes induce both antiviral and antiproliferative activities in vitro and are capable of upregulating the feMx gene in vivo., (Copyright 2004 Elsevier B.V.)

Our previous study showed that recombinant canine IL-13 (rcaIL-13) stimulated production of allergen-specific IgE in vitro by peripheral blood mononuclear cells (PBMC) from flea allergen-sensitized dogs. This has also been demonstrated using human IL-13 (huIL-13) and PBMC isolated from human allergy patients. The stimulatory activity of rcaIL-13 was specifically inhibited by a fusion protein of the extracellular domain of canine IL-13Ralpha2 and the Fc fragment of canine IgG heavy chain (rcaIL-13Ralpha2-Fc). In this communication, we report the construction and expression of a non-fused recombinant extracellular domain of canine IL-13Ralpha2 (rcaIL-13Ralpha2) in an E. coli expression system. The E. coli expressed rcaIL-13Ralpha2 was isolated in inclusion bodies, then solubilized in buffer containing denaturants and reducing agents. After refolding and purification, the biological activity of rcaIL-13Ralpha2 was found in the monomer fraction resulting from gel filtration and ion exchange chromatographies. Biological activity of purified rcaIL-13Ralpha2 was demonstrated by the specific inhibition of rcaIL-13 activity in a TF-1 cell proliferation assay. Additionally, rcaIL-13Ralpha2 was found to be active in neutralizing rcaIL-13 induced upregulation of IgE mRNA levels in PBMCs of "high IgE" dogs, which have been bred to exhibit a predisposition for high IgE production and are used as a model for allergic asthma. The data confirm our previous report that the regulatory effects of IL-13 on IgE production in canine PBMCs are similar to those reported in humans. Thus, allergic dogs, such as the "high IgE" producing dogs, may be excellent models for research on IgE-mediated diseases in humans.

Neoplastic cells are believed to evade the immune system due, in part, to their inability to successfully provide a secondary, costimulatory signal for a T lymphocyte proliferative response. This report describes the generation and investigation of genetically engineered canine mammary tumor (CMT) cells that express canine B7-1, canine B7-2, or human B7-2. These transfected cells were used as stimulators in an allogeneic, costimulation assay. CMT cells transfected with canine B7-1 induced the greatest proliferation (7-fold increase), followed by CMT cells transfected with canine B7-2 (5-fold increase). The specificity of the canine B7-2 stimulatory response was demonstrated by a 38% reduction in proliferation caused by an anti-canine B7-2 blocking antibody. These results suggest that canine mammary tumor cells transfected with canine B7-1 or canine B7-2 may be useful for immunotherapeutic purposes.