Two is not necessarily better than one: A double lens in a pre-metamorphic adult axolotl (Ambystoma mexicanum)

An 8-year-old female pre-metamorphic axolotl (Ambystoma mexicanum) was examined for a suspected anterior lens luxation. Slit-lamp biomicroscopy revealed two lens-like structures in the anterior chamber of the right eye (OD), each with cataractous change. Ultrasound biomicroscopy and optical coherence tomography (OCT) were performed without sedation, and revealed small lenticular structures each with distinct nuclei and cortices. Although a distinct connection of the two lenticular structures could not be definitively ruled out, the structures appeared separate. Each of the lenticular structures was closely associated with its respective iris leaflet. This report demonstrates application of advanced imaging for diagnostic use in axolotl ophthalmology, showing that imaging of the lens can be performed without sedation, topical anesthetic, nor contact gel with high diagnostic quality. Although two distinct lenses were diagnosed with no historical evidence of trauma, the small sizes of each lenticular structure, with no detectable connection between them, are suggestive of a possible regenerative abnormality. This report opens discussion for the regenerative capabilities of the pre-metamorphic adult axolotl and possible implementations of their use in regenerative medicine research for the development of future therapies.     

Once in a blue moon: Lipid keratopathy and intrastromal hemorrhage in a Mission golden‐eyed tree frog (Trachycephalus resinifictrix)

Mimicking natural anuran biology is a major challenge faced in the husbandry management of frogs, and the quandary of lipid keratopathy in frogs under human care has plagued keepers and practitioners for decades. Unlike corneal lipid dystrophy or lipidosis secondary to degeneration, where there is limited or no vascular in‐growth or inflammatory response, lipid keratopathies are associated with vascularization, most often following the appearance of lipid. Hemorrhage from stromal neovascularization has not been described in a frog; however, the presence of vessels in lipid keratopathy certainly heralds the possibility. We report a rather unique case of lipid keratopathy in a 6‐year‐old female Mission golden‐eyed tree frog (Trachycephalus resinifictrix) that not only had concurrent intrastromal hemorrhage, but blue plasmoid staining of the corneal stroma. Current views on both the function of blue plasma in several species and lipid keratopathy are briefly discussed. Overall, evidence suggests that the cause of lipid keratopathy is probably multifactorial and will not successfully be rectified until anuran biology and husbandry are better understood.     

Effects of intramuscular meloxicam administration on prostaglandin E2 synthesis in the North American bullfrog (Rana catesbeiana)

Meloxicam is a commonly used nonsteroidal anti-inflammatory drug (NSAID) in veterinary medicine, but its use in amphibians has not been reported in the literature. NSAIDs are known to act by providing anti-inflammatory and analgesic actions by inhibiting the synthesis of prostaglandin E2 (PGE2). The objective of this study was to evaluate whether the intramuscular administration of meloxicam would decrease the circulating serum PGE2 levels in the North American bullfrog (Rana catesbeiana) following tissue trauma induced by a punch biopsy. Eighteen adult North American bullfrogs were randomly assigned to two treatment groups: meloxicam (0.1 mg/kg i.m.) and control (0.9% saline i.m.). Blood was obtained via cardiocentesis immediately prior to administration of the two treatment regimes and serum was frozen. A 4-mm punch biopsy was taken from the right triceps femoris muscle to induce an inflammatory response. Twenty-four hours later, a second blood sample was collected and serum was harvested and frozen. Serum PGE2 concentrations were measured using a commercial PGE2 enzyme assay (EIA) kit. Twenty-four hours following the biopsy, the mean circulating PGE2 levels of animals treated with meloxicam was 57.79 +/- 12.35 pg/ml, which did not differ significantly from animals that were treated with saline (85.63 +/- 17.55 pg/ml, P > or = 0.05). The calculated means of the absolute change between the circulating baseline PGE2 levels and the postinjury circulating PGE2 levels were significantly lower in animals treated with meloxicam (13.11 +/- 17.31 pg/ml) than in control animals treated with saline (46.14 +/- 38.02 pg/ml) (P < or = 0.05). These results suggest that the systemic administration of meloxicam at a dosage of 0.1 mg/kg once daily suppresses circulating serum PGE2 levels postinjury in the North American bullfrog.