Histologic and cytologic changes in normal equine joints after injection with 2.5% injectable polyacrylamide hydrogel reveal low-level macrophage-driven foreign body response.

OBJECTIVE: The data presented in this paper are derived from an in vivo study performed to characterize the nature of the synovial integration process of a 2.5% synthetic cross-linked injectable polyacrylamide hydrogel (2.5 iPAAG) injected IA in horses. ANIMALS: 10 healthy horses not suffering from OA or signs of joint disease were administered 50 or 100 mg 2.5 iPAAG in a total of 13 metacarpophalangeal or middle carpal joints. METHODS: Injected joints were examined at 0, 14, 42, and/or 90 days postinjection. Parameters investigated included clinical examination, synoviocentesis, gross pathology, histology, and scanning electron microscopy. RESULTS: All horses remained clinically normal, with no adverse events recorded throughout the study period. Gross postmortem did not reveal any significant findings. Arthrocentesis cytology parameters remained within clinically normal levels throughout the study. Synovial histology demonstrated that cellular infiltration of macrophages, villus hyperplasia, and vascularization were significantly higher in 2.5 iPAAG-injected joints compared to controls. Scanning electron microscopy confirmed that the 2.5 iPAAG demonstrated an extensive tissue integration as a 3-D scaffolding structure with intact cross-linked strands. CLINICAL RELEVANCE: Results confirm that an IA injection of 2.5 iPAAG induces a typical foreign body response that is predominately macrophage driven with no evidence of fibrosis or mineralization. Integration of the gel is evident by 14 days, with no free gel remaining in the joint cavity at this time.

Cutaneous papilloma associated with a novel papillomavirus sequence in a cat.

A 5-mm diameter mass developed on the nasal planum of a 4.5-y-old castrated male domestic shorthaired cat; the mass was raised ~2 mm above the surrounding skin. Histology revealed focal thickening of the epidermis with marked orthokeratosis. Many of the epidermal cells within the mass had prominent papillomavirus-induced changes. A diagnosis of a viral papilloma was made, and a DNA sequence from a novel papillomavirus type was amplified from the lesion. Although the sequence was most similar to other feline papillomavirus types, the low level of similarity was suggestive of a novel papillomavirus genus. There has been no recurrence of the mass or development of additional lesions in the 6 mo since the mass was removed. This is the third cutaneous papilloma reported in a cat; a putative feline papillomavirus type has not been identified previously within these lesions, to our knowledge. Our findings expand the range of lesions associated with papillomaviruses in cats and increase the number of papillomavirus types that infect cats.

Long-term recurrent, yet nonprogressive, pedal viral papillomas in a dog.

Viral papillomas that developed on the toe of a dog, were removed and recurred four times in two years. Despite the papillomas being 'persistent', they remained small and confined to the toe, and did not spread or progress to severe disease. Not all persistent papillomas will progress, even when these are treated using more conservative therapies.

Les papillomes viraux développés sur le doigt d'un chien ont été retirés et ont récidivés à quatre reprises en deux ans. Malgré la « persistance ¼ des papillomes, ils sont restés petits et confinés aux doigts, et n'ont pas disséminés ou ne se sont pas aggravés. Tous les papillomes persistants ne progressent pas, même si ils sont traités avec des traitements plus conservateurs.

Los papilomas virales que se desarrollaron en un dedo de un perro, fueron extirpados y reaparecieron cuatro veces en dos años. A pesar de que los papilomas son "persistentes", permanecieron de pequeño tamaño y confinados al dedo del pie, y no se diseminaron ni progresaron a una enfermedad grave. No todos los papilomas persistentes progresan, incluso cuando se tratan con terapias más conservadoras.

Papilomas virais que se desenvolveram no dígito de um cão foram removidos e tiveram recorrência quatro vezes em um período de dois anos. Apesar de os papilomas serem persistentes, eles permaneceram pequenos e limitados ao dígito, e não se espalharam ou progrediram para doença grave. Nem todos os papilomas persistentes vão progredir, mesmo quando estes são tratados utilizando terapias mais conservadoras.

Clove Oil Delays Rather Than Prevents Scur/Horn Growth in Dairy Cattle.

The objective of this study was to evaluate if administration of clove oil prevents scur/horn growth in dairy cattle long term. At approximately 4 days of age, calves had one of four treatments assigned to each horn bud: (1) clove oil administered subcutaneously under the horn bud (CLOV, n = 132); (2) cautery disbudded and the horn bud removed (BUDOFF, n = 126); (3) cautery disbudded and the horn bud tissue left intact (BUDON, n = 129); (4) a liquid nitrogen filled probe applied to the horn bud area (CRYO, n = 131). At approximately 16 months of age, all cattle were checked for scur or horn development. A sub-set of scurs/horns from the CLOV cattle were removed to evaluate tissue and structural development. In total, 5% of CLOV buds developed into horns and 63% into scurs; 10% of the scurs looked like normally developed horns but they were not attached to the skull. Cautery disbudding prevented scur and horn development in cattle when the horn bud tissue was removed, but some scur growth was observed in the BUDON treatment. CRYO was 100% ineffective at preventing scur/horn growth. Injecting clove oil under the horn bud appeared to delay horn development, but not prevent it, when administered to 4 day old dairy calves.

Virulence of Rhodococcus equi isolated from cats and dogs.

Nine cat isolates and nine dog isolates of Rhodococcus equi from clinical material were investigated for the presence of the virulence-associated antigens (VapA and VapB) and virulence plasmids. Five of the cat isolates and one dog isolate were VapA positive and contained an 85-kb type I or an 87-kb type I plasmid. The remaining 12 isolates were avirulent R. equi strains and contained no virulence plasmids.