Viral diseases of the Ostrich (Struthio camelus var. domesticus)

The ostrich is an important animal in many livestock industries. A significant threat to this industry is losses from diseases. Newcastle disease is a notifiable, highly contagious viral infection of ostriches. Avian influenza may be transmitted from waterfowl, shorebirds and gulls to ostriches. Borna disease virus is a viral neurotropic infection spread mainly by rodents and felines. Crimean‐Congo hemorrhagic fever is a viral disease transmitted by Hyalomma ticks to humans. Avipoxvirus afflicts ostrich chicks and is transmitted by mosquitoes or by direct contact with a pox lesion. Maintenance of a healthy and profitable enterprise requires the implementation, with assistance from the local veterinary authority, of comprehensive, practical and effective methods of health management and preventative medicine.     

Purification and characterization of feline ghrelin and its possible role

Ghrelin, a novel 28-amino acid peptide with an n-octanoyl modification at Ser3, has been isolated from rat and human stomach as an endogenous ligand for the growth hormone secretagogue receptor. Here, we purified feline ghrelin and examined its possible physiological role in cats. The major active form of feline ghrelin is a 28-amino acid peptide octanoylated (C8:0) at Ser3; except for one amino acid residue replacement, this structure is identical to those of rat and human ghrelins. However, much structural divergence in peptide length and fatty acid modification was observed in feline ghrelin: peptides consisting of 27 or 26 amino acids lacking Gln14 and/or Arg28 were found, and the third serine residue was modified by octanoic acid (C8:0), decanoic acid (10:0), or unsaturated fatty acids (C8:1, C10:1 and C10:2). In agreement with the structural divergence, two kinds of cDNA with different lengths were isolated. Administration of synthetic rat ghrelin increased plasma growth hormone levels in cats, with a potency similar to that in rat or human. Plasma levels of ghrelin in cats increased approximately 2.5-fold after fasting. The present study indicates the existence of structural divergence in feline ghrelin and suggests that, as in other animals, ghrelin may play important roles in GH release and feeding in cats.     

Combined effects of treatment with trientine, a copper-chelating agent, and x-irradiation on tumor growth in transplantation model of a murine fibrosarcoma

Combined effects of treatment with trientine, a copper-chelating agent, and X-irradiation on development of fibrosarcoma using a murine transplantation model in vivo and on cellular survival in vitro were examined. Copper contents in the tumors and serum of trientine-treated mice were significantly lower than those of untreated mice. The tumor volumes of mouse fibrosarcoma QRsp-11 cells increased more slowly in the trientine-treated and the X-irradiated mice than in the control mice from 10 to 24 days postinoculation. The extent of inhibition of tumor growth by X-irradiation at 3 Gy was similar to that obtained by treatment with trientine. A combination of trientine and X-irradiation at 3 Gy showed inhibitory effects on tumor growth similar to those obtained by X-irradiation at 6 Gy. The results showed that trientine and X-irradiation interacted additively in inhibition of tumor growth. When QRsp-11 cells and mouse and bovine endothelial cells were treated with trientine after X-irradiation, the surviving fractions of the cells with combined treatments were essentially consistent with the products of the surviving fractions of trientine-treated cells and those of X-irradiated cells. When the cells were pretreated with trientine and X-irradiated, the surviving fractions of the pretreated cells were lower than those of cells without treatment.     

Changes in expression and localization of GPRC5B and RARalpha in the placenta and yolk sac during middle to late gestation in mice

The mRNA expression of GPRC5B, an orphan G protein-coupled receptor, is induced by retinoic acid (RA). Because RA plays critical roles in embryonic development, reproductive functions, metabolism and homeostasis, GPRC5B is also considered crucial in these physiological events. We investigated the changes in expression of GPRC5B and RA receptor (RAR) alpha mRNAs and immunohistochemical localization of their proteins in the murine placenta and yolk sac at 13.5, 15.5 and 17.5 days post coitus. Stable levels of GPRC5B and RARalpha mRNAs were detected in the placenta and yolk sac. In the placenta, GPRC5B was present in maternal and fetal vascular endothelial cells, stromal cells, fibroblast-like cells and glycogen cells. A strong reaction to RARalpha was detected in maternal and fetal vascular endothelial cells and stromal cells. The levels of GPRC5B and RARalpha proteins in maternal and fetal vascular endothelial cells decreased with gestation. In the yolk sac, GPRC5B and RARalpha proteins were detected in vascular endothelial cells, but their levels did not change during the gestation period. These findings indicate that GPRC5B is involved in RA-dependent morphogenesis/angiogenesis and regulation of extracellular matrix synthesis in the murine placenta and yolk sac.     

Estimation of daily urinary potassium excretion using urinary creatinine as an index substance in prepartum dairy cows

In the present study, the daily excretion of potassium (K) in urine (urinary K(UK)) was estimated from a 6 h urine sample using urinary creatinine (UC) as the index substance. All urine was collected from six pregnant Holstein cows at 6 h intervals for 24 h on 3 days of the 4th, 2nd and final week before the expected date of parturition. In total, 72 6 h urine samples were obtained. Daily UC excretion (mg/day per kg bodyweight (BW)) was almost the same for the three sampling days. Daily UC excretion varied among cows from 22.1 to 24.3 mg/day per kg BW with a mean of 22.8 mg/day per kg BW with no significant difference. Thus, daily UC excretion was confirmed to be constant throughout the prepartum period with no differences among individuals. The concentration ratios of K to creatinine ((UK mg/dL)/(UC mg/dL) (UK/UC)) correlated strongly to the hourly K excretions (mg/h per kg BW) (r = 0.952, P < 0.01) in the 6 h urine samples. The differences in the UK/UC ratio between sampling periods were not significant within each cow. Therefore, daily UK excretion (mg/day) can be estimated using the equation: daily UK excretion (mg/day) = daily UC excretion (mg/day per kg BW) × BW (kg) × 6 h urine sample UK/UC, where daily UC excretion can be a given value.     

Comparison of canine heartworm removal rates using flexible alligator forceps guided by transesophageal echocardiography and fluoroscopy

Fluoroscopy (FS)- or transesophageal echocardiography (TEE)-guided heartworm removal was carried out using flexible alligator forceps to compare the rate of worm removal. As a result, the worm removal rates were similar between the two procedures. However, the TEE-guided procedure does not involve radiation exposure, and facilitates observation of worms in the cardiac chamber and pulmonary artery. Therefore, the TEE-guided procedure is thought to be more useful than the FS-guided procedure in clinical setting.     

A role for balance of interferon-gamma and interleukin-4 production in protective immunity against Neospora caninum infection

A suitable balance in the production of Th1/Th2-type cytokines has a crucial role in the control of microbial infections. We investigated cytokine production patterns and effects during Neospora caninum infection, based on two mouse models and an in vitro system. In the acute infection of N. caninum, BALB/c-background IFN-gamma-deficient mice that were sensitive to the N. caninum infection showed high levels of IL-10 production, whereas significant levels of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production were observed in resistant wild type mice. BALB/c mice vaccinated with recombinant vaccinia virus expressing N. caninum surface protein NcSRS2 resisted parasite spread throughout the body, low levels of IFN-gamma production and high levels of IL-4 production were observed compared to unvaccinated animals. The treatment of N. caninum-infected cells with IFN-gamma or IL-10 decreased the host-cell viability in an in vitro system using mouse macrophage J774A.1 cells. On the other hand, IL-4, but not IL-10 administration, increased the viability of N. caninum-infected and IFN-gamma-treated cells. In the light of the balance of Th1/Th2-type cytokine production, an IFN-gamma/IL-4 balance may have a crucial role for the control of cellular responses against the parasite invasion.