Determining MMP-2 and MMP-9 reductive activities of bovine and equine amniotic membranes homogenates using fluorescence resonance energy transfer.

INTRODUCTION: Matrix metalloproteinases (MMPs)-2 and -9 are present in corneal ulcers, and an imbalance between MMPs and tissue inhibitors of metalloproteinases (TIMPs) leads to further corneal degradation. Amniotic membrane homogenate (AMH) has proteolytic properties beneficial for corneal healing, but it is unknown whether AMH possesses TIMPs or effectively inhibits MMP-2 and MMP-9 activity. OBJECTIVE: To determine if bovine and equine AMH reduce in vitro MMP-2 and MMP-9 activities associated with the presence of TIMPs. PROCEDURES: Undiluted and diluted twofold series (0-fold to 16-fold dilutions) of equine amniotic membrane homogenates (EAMH, n = 8) and bovine amniotic membrane homogenates (BAMH, n = 8) were subjected to fluorescence resonance energy transfer, and the fluorescence emitted was recorded over time. Average fluorescence was calculated versus recombinant concentration. Enzyme-linked immunosorbent assays for TIMPs 1-4 were applied to quantify TIMPs in the samples. RESULTS: AMH from both species were able to inhibit MMP-2 and MMP-9 activities in vitro, and the inhibition efficacy decreased gradually with dilution. BAMH was significantly more effective than EAMH at inhibiting MMP-2 and MMP-9 in vitro. TIMPs -2 and -3 were present in EAMH and BAMH. TIMP-1 was detected only in BAMH, and TIMP-4 was not detected in any samples. CONCLUSION: Both EAMH and BAMH directly inhibited MMP-2 and MMP-9 in vitro without dilution, and BAMH showed better inhibition of MMP-2 and MMP-9 before and after dilution compared to EAMH.

Osmolarity of basal and reflex tears of normal dogs.

OBJECTIVE: To compare basal and reflex tear osmolarity in healthy dogs and to evaluate for correlation among tear film osmolarity, tear production, and tear fern pattern. ANIMALS STUDIED: The population consisted of 22 healthy adult dogs. PROCEDURES: Reflex tear osmolarity was measured in both eyes using the I-PEN®  VET osmometer 30 minutes following the Schirmer tear test (STT-1) measurement. Subsequently, two minutes following topical anesthetic application, the lacrimal lake and conjunctival fornices were dried, and 3 minutes later, basal tear osmolarity was measured. Tears were extracted from the dye-free STT-1 strip by centrifugation, placed on a glass slide, and the ferning pattern was determined by light microscopy. Comparisons between basal and reflex tears were performed with one-way ANOVA. Correlations between tear osmolarity, STT-1, and tear ferning were verified by Pearson's correlation coefficient. RESULTS: No statistical difference was found between right and left eyes for STT-1, tear fern pattern, and osmolarity of reflex or basal tears (P < .05). There was no statistical difference between osmolarity of basal and reflex tears among individuals (P < .05). No correlation was detected between tear fern pattern and osmolarity of reflex tears. A weak positive correlation was detected between STT-1 values and osmolarity of reflex, but not basal tears. CONCLUSIONS: The osmolarity of basal tears did not differ from that of reflex tears. A positive weak correlation exists between tear production and osmolarity of reflex tears. No correlation was detected between tear osmolarity measured by handheld osmometer and tear ferning.

Use of 1% polidocanol and pre- and post-computed tomography for treatment of a suspected nasolacrimal duct cyst in a dog.

OBJECTIVE: To describe the efficacy of the sclerosing agent 1% polidocanol in the treatment of a suspected nasolacrimal duct cyst in a dog. ANIMAL STUDIED: A 5-year-old castrated male Golden Retriever with chronic epiphora of the right eye. PROCEDURES: Ocular examination revealed epiphora and a negative Jones test of the right eye and was otherwise normal. Computed tomography with dacryocystography confirmed a cystic structure in the right ventral orbit that extended into the caudal nasal cavity adjacent to the orbit, causing partial physical obstruction of the right nasolacrimal duct. Cytologic analysis of fluid from the lesion was supportive of a diagnosis of a cyst. One percent polidocanol (compounded, People's Custom Rx, Memphis, TN) was injected into the cyst. RESULTS: Epiphora was resolved by two weeks post-injection. Repeated computed tomography with dacryocystography was performed 8 months post-injection, revealing complete resolution of the cyst and demonstrating mild enophthalmos of the right globe. CONCLUSIONS: Intralesional 1% polidocanol therapy was successful in resolving a suspected nasolacrimal duct cyst in a dog.

Evaluation of transconjunctival thermal electrocautery for treatment of canine distichiasis: 88 eyelids (2013-2016).

OBJECTIVE: To describe a successful, simple treatment for canine distichiasis. ANIMALS STUDIED: Client-owned dogs presenting to Veterinary Specialty and Emergency Center, Levittown, Pennsylvania. PROCEDURE: Retrospective analysis of medical records for canine patients that underwent transconjunctival thermal electrocautery treatment (TCEC) for distichiasis alone or with concurrent eyelid surgery between 2013 and 2016. Fifty eyes of 26 dogs (n = 88 eyelids) were included in the study. Sixty-five eyelids (74%) were treated for distichia only, while 23 eyelids (26%) underwent concurrent eyelid surgery. Successful treatment was defined as resolution of clinical signs attributable to distichiasis. Forty-eight of 50 eyes (96%) were successfully treated with a single TCEC treatment (mean follow-up 187 ± 222 days). Sixty-one of 88 eyelids (69%) had no distichia at any follow-up time. Twenty-two eyelids (25%) had recurrence at or near a previously treated site (mean 150 ± 152 days). Of the eyes with recurrent distichia, all but 2 (91%) remained asymptomatic, requiring no further treatment. One dog with extensive TCEC treatment had significant recurrence on all eyelids requiring retreatment that resulted in focal entropion of 1 eyelid. Transient eyelid margin pigment loss and mild-to-moderate eyelid swelling were noted in all treated eyelids postoperatively. Suspected treatment site infection occurred 2 days postoperatively in 2/50 eyes (4%) of 1 patient. Two of 10 eyes (20%) with extensive eyelid treatment developed qualitative tear film deficiency OU (554 days postoperatively) and responded to topical tear stimulant therapy. CONCLUSION: TCEC is a successful, simple treatment for canine distichiasis.