Iron modulates the replication of virulent Mycobacterium bovis in resting and activated bovine and possum macrophages

Bovine and possum macrophages were infected in vitro with a virulent strain of Mycobacterium bovis, and mycobacterial replication was measured in the infected macrophages cultured under a variety of conditions. Virulent M. bovis replicated substantially in alveolar possum macrophages as well as in bovine blood monocyte-derived macrophages. Addition of recombinant bovine interferon-gamma (IFN-gamma) with low concentrations of lipopolysaccharide (LPS) rendered bovine macrophages significantly more resistant to M. bovis replication. Disruption of iron levels in infected macrophages by addition of apotransferrin or bovine lactoferrin blocked replication of M. bovis in both bovine and possum macrophages. On the other hand, addition of exogenous iron, either in the form of iron citrate or iron-saturated transferrin, rendered macrophages of both species much more permissive for the replication of M. bovis. The impact of iron deprivation/loading on the mycobacteriostatic activity of cells was independent of nitric-oxide release, as well as independent of the generation of oxygen radical species in both possum and bovine macrophages. Exogenous iron was shown to reverse the ability of IFN-gamma/LPS pulsed bovine macrophages to restrict M. bovis replication. When autologous possum lymphocytes from animals vaccinated with M. bovis strain BCG were added to infected macrophages, they rendered the macrophages less permissive for virulent M. bovis replication. Loading the cells with iron prior to this macrophage-lymphocyte interaction, reversed this immune effect induced by sensitized cells. We conclude that, in two important animal species, intracellular iron level plays an important role in M. bovis replication in macrophages, irrespective of their activation status.     

Phaeochromocytoma treated by en bloc resection including the suprarenal caudal vena cava in a dog

A 10-year-old, neutered male Cairn terrier was examined after experiencing intermittent vomiting of several months' duration and sudden onset of acute depression. Abdominal ultrasound examination revealed an adrenal mass invading the suprarenal part of the caudal vena cava. The vascular invasion could not be corrected so en bloc ligation/excision of the adrenal neoplasm and the suprarenal part of the vena cava was performed. Microscopic examination identified an adrenal phaeochromocytoma. The dog recovered well and had no significant vascular or renal dysfunction at follow-up 20 months after surgery. To the authors' knowledge, this is the first report of a dog surviving long term after resection of the suprarenal caudal vena cava.     

Hypertensive retinopathy and choroidopathy in a cat

Bilateral hypertensive retinopathy and choroidopathy with bullous retinal detachment was diagnosed in a 17-year-old, female spayed Domestic Short-haired cat. The underlying cause of the systemic hypertension could not be determined. The blood pressure was lowered successfully with the oral application of the L-type calcium channel blocker amlodipine besylate. The cat subsequently regained vision. The improvement in retinal function was documented using electroretinography.     

Lactoferrin against Staphylococcus aureus Mastitis. Lactoferrin alone or in combination with penicillin G on bovine polymorphonuclear function and mammary epithelial cells colonisation by Staphylococcus aureus

Antibiotics should combine good antibacterial activity and the capacity to work in association with the host defence system. In this study, we have investigated the effects of bovine lactoferrin alone or in combination with penicillin G on the phagocytic activity of bovine polymorphonuclear leukocytes against Staphylococcus aureus. We have shown that susceptibility of S. aureus to phagocytosis was decreased in the presence of penicillin in the medium. In a kinetic study, lactoferrin alone did not affect phagocytosis but, when used with penicillin, it reversed the negative effect of this antibiotic on phagocytosis. In addition, in an epithelial invasion assay, lactoferrin alone or in combination with penicillin reduced the invasion of mammary epithelial cells in culture by S. aureus. Lactating female CD-1 mice were infected by intra-mammary delivery of a virulent penicillin-susceptible S. aureus strain and were then randomly assigned to treatments according to a 2 x 2 factorial design. In this mouse mastitis model, 2 days of systemic treatments with lactoferrin and/or penicillin did not lead to a total clearance of infection by S. aureus, but bacterial number was significantly reduced by treatments with lactoferrin or penicillin. These data suggest that bovine lactoferrin, alone or in combination with penicillin G, enhances S. aureus susceptibility to immuno-defense mechanisms, which can be beneficial in the treatment of S. aureus infections.     

Anterior lens capsule disruption and suspected malignant glaucoma in a dog

A Boston Terrier puppy presented with a full-thickness peripheral corneal defect, iris prolapse and anterior lens capsule tear in the left eye (OS). Phacofragmentation and primary repair of the corneal laceration was performed. At surgery, subluxation of the lens was also apparent. One day postoperative, there was severe corneal edema, diffuse hyphema, an intraocular pressure (IOP) of 65 mmHg and a small amount of vitreous that protruded from the corneal incision OS. Malignant glaucoma or pupillary block glaucoma were suspected. Intravenous mannitol was administered preoperatively and had no effect. An anterior vitrectomy was performed on the vitreous within the anterior chamber and pupil. One day postoperative the IOP was 16 mmHg in the right eye (OD) and 20 mmHg OS. Postoperative iridocyclitis was managed medically, and additional elevations in IOP were not recorded. Resolution of the elevated IOP following anterior vitrectomy was supportive of pupillary block or malignant glaucoma. Vision returned 3 weeks after the initial surgery. Two years after the initial injury, the eye is visual and comfortable with infrequent topical anti-inflammatory therapy.     

Preweaning mortality.

A number of factors, both infectious and noninfectious, contribute to preweaning mortality in pigs. It is important to establish the causes of preweaning mortality and their distribution in investigating farm problems. The various causes, risk factors, and a step-by-step approach to solving the problem are discussed.     

Assistive devices, orthotics, and prosthetics.

Deciding on which supportive device, orthotic, or prosthetic is best suited for a given patient is a complex process involving many different factors. The ability to manage biomechanical abnormalities successfully may be enhanced by an understanding of the properties of the various materials that comprise these devices, their effect on functional performance, and other associated patient factors. Veterinary health care providers are faced with the challenge of effectively addressing the physiologic and fiscal needs of the patient in a rapidly changing patient care environment.