Publications by authors named "David J Maggs"

89 Publications

Choroidal neuroendocrine neoplasia in a dog.

Vet Ophthalmol 2021 Feb 22. Epub 2021 Feb 22.

Department of Veterinary Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.

Objective: To report onset and progression of clinical signs of a neuroendocrine neoplasm (NEN) presumed metastatic to the choroid in a dog.

Animals Studied: A 7.5-year-old female spayed German shepherd dog mix referred for advanced imaging and evaluation of a subretinal mass in the right eye.

Procedures: Procedures performed included general physical and ophthalmic examinations; ocular, orbital, and abdominal ultrasonography; thoracic radiographs; cranial magnetic resonance imaging; serologic testing for infectious agents; analysis of hematologic as well as serum and urine biochemical parameters; echocardiography; electrocardiography; cytologic assessment of lymph nodes; and histopathology and immunohistochemistry of the enucleated globe.

Results: Examination and imaging identified a pigmented mass within and expanding the superior choroid. Following enucleation, a choroidal NEN with tumor emboli in scleral blood vessels was diagnosed by histopathologic assessment and confirmed by immunohistochemical labelling. Despite extensive and repeated diagnostic testing over many months, a putative primary site was not identified until 19 months after the initial ocular signs were noted. At that time, a heart-base mass and congestive heart failure were highly suggestive of a chemodectoma.

Conclusion: This comprehensive report of a NEN presumed metastatic to the choroid in a dog suggests that ocular disease can be a very early and solitary sign of NEN in the dog.
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http://dx.doi.org/10.1111/vop.12875DOI Listing
February 2021

Altered Corneal Innervation and Ocular Surface Homeostasis in FHV-1-Exposed Cats: A Preliminary Study Suggesting Metaherpetic Disease.

Front Vet Sci 2020 26;7:580414. Epub 2021 Jan 26.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States.

Metaherpetic disease is recognized in humans affected by herpes simplex virus-1 but is not reported in cats affected by feline herpesvirus-1 (FHV-1) despite the high prevalence of herpetic disease in this species and strong similarities in viral biology between alphaherpesviruses of humans and cats. This preliminary work evaluated cats naïve to FHV-1 ( = 9 cats, 18 eyes; control population) and cats naturally exposed to FHV-1 ( = 4 cats, 7 eyes), as confirmed by serologic testing and review of medical records. Antemortem assessment included clinical scoring, blink rate, corneal aesthesiometry, tear film breakup time (TFBUT), and Schirmer tear test-1 (STT-1) with or without the nasolacrimal reflex. Post-mortem assessment involved confocal microscopy of the corneas and evaluation of corneal nerves with ImageJ. Groups were compared with Student's -tests and results are presented as mean ± standard deviation. Compared to control, herpetic cats had significantly higher ( ≤ 0.010) clinical scores (0.2 ± 0.4 . 4.6 ± 2.8) and response to nasolacrimal stimulation (7.8 ± 10.8% . 104.8 ± 151.1%), significantly lower ( < 0.001) corneal sensitivity (2.9 ± 0.6 cm . 1.4 ± 0.9 cm), STT-1 (20.8 ± 2.6 mm/min . 10.6 ± 6.0 mm/min), TFBUT (12.1 ± 2.0 s . 7.1 ± 2.9 s), and non-significantly lower blink rate (3.0 ± 1.5 blinks/min . 2.7 ± 0.5 blinks/min; = 0.751). All parameters evaluated for corneal nerves (e.g., nerve fiber length, branching, occupancy) were notably but not significantly lower in herpetic . control cats ( ≥ 0.268). In sum, cats exposed to FHV-1 had signs suggestive of corneal hypoesthesia and quantitative/qualitative tear film deficiencies when compared to cats naïve to the virus. It is possible these are signs of metaherpetic disease as reported in other species.
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http://dx.doi.org/10.3389/fvets.2020.580414DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7870478PMC
January 2021

Subcutaneous administration of triamcinolone as part of the management of feline eosinophilic keratoconjunctivitis.

J Feline Med Surg 2020 Nov 3:1098612X20968660. Epub 2020 Nov 3.

Department of Surgical and Radiological Sciences, University of California-Davis, Davis, CA, USA.

Objectives: The aim of this retrospective case-control study was to report the efficacy of subcutaneous triamcinolone as part of a regimen for feline eosinophilic keratoconjunctivitis (FEK).

Methods: Records and clinical photographs were reviewed and lesions semi-quantitatively graded for cats with cytologically confirmed FEK. Clinical data were compared between a study population of nine cats (11 eyes) treated with, and a reference population of seven cats (eight eyes) treated without, a median 0.11 mg/kg (range 0.10-0.20 mg/kg) of triamcinolone acetonide subcutaneously.

Results: Breed, sex, age and prevalence of corneal ulceration at presentation; corneal disease severity before and at the initiation of immunomodulation; and duration of antiviral treatment before immunomodulation did not differ significantly between populations ( ⩾0.059). Corneal plaques resolved in five cats each from the study and reference populations ( = 0.366). Median (range) time from immunomodulation to corneal plaque resolution did not significantly differ ( = 0.246) between the study (median 14 days; range 8-38 days) and reference (median 28 days, range 14-46 days) populations. No adverse reactions were attributed to triamcinolone administration, and all corneal ulcers in the study population re-epithelialized within 14 days (range 8-38 days) following triamcinolone injection. Time to corneal ulcer re-epithelialization following triamcinolone injection varied minimally in those receiving antivirals prior to (8 or 30 days until re-epithelialization), simultaneously with (38 days) or after (14 or 24 days) triamcinolone.

Conclusions And Relevance: In otherwise healthy cats with FEK, subcutaneous administration of triamcinolone appears to be well tolerated and as efficacious as conventional topical immunomodulatory therapies. It may be especially useful in ulcerated eyes where topical immunomodulation is contraindicated.
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http://dx.doi.org/10.1177/1098612X20968660DOI Listing
November 2020

A Retrospective Study of Corneal Endothelial Dystrophy in Dogs (1991-2014).

Cornea 2020 Sep 16. Epub 2020 Sep 16.

Departments of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA.

Purpose: To retrospectively evaluate the clinical data, diagnostic tests, treatments, and outcomes for dogs with corneal endothelial dystrophy (CED) and determine risk factors for CED when compared with a canine reference population.

Methods: Medical records of 99 dogs (1991-2014) diagnosed with CED at the University of California Davis Veterinary Medical Teaching Hospital were reviewed and compared with 458,680 dogs comprising the general hospital population during the study period. Retrieved data included signalment, examination findings, diagnoses, treatments, and outcomes associated with CED. The exact Pearson χ test or exact Kruskal-Wallis test was used to compare parameters between the groups. Progression of corneal edema was assessed using 3 independent Kaplan-Meier curves, identifying clinically significant changes in corneal opacity.

Results: Boston terriers, German wirehaired pointers, and Dachshunds were overrepresented in the CED-affected group, whereas Labradors were underrepresented. Dogs older than 11 years were overrepresented in the CED-affected group, whereas intact dogs were underrepresented. Surgical intervention was performed (n = 11) based on the severity of disease and secondary complications from CED. Median time to progression of corneal edema was 1) 368 days when an at-risk eye initially without edema developed edema at a subsequent visit, 2) 701 days when there was progression from mild to marked corneal edema, and 3) 340 days when there was progression from focal to diffuse corneal edema.

Conclusions: Many CED-affected dogs progress over months to years without surgical intervention, making dogs with CED a useful model for studying genetic predispositions and development of novel therapeutics for Fuchs endothelial corneal dystrophy.
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http://dx.doi.org/10.1097/ICO.0000000000002488DOI Listing
September 2020

Feline conjunctival microbiota in a shelter: effects of time, upper respiratory disease and famciclovir administration.

J Feline Med Surg 2020 Aug 21:1098612X20949038. Epub 2020 Aug 21.

Department of Pathobiology, University of Guelph, Guelph, ON, Canada.

Objectives: The aim of this study was to evaluate changes in the conjunctival microbiota of shelter-housed cats with time, upper respiratory disease (URD) and famciclovir administration.

Methods: Cats were assigned to treatment groups on shelter entry. Healthy cats or cats with URD received ~30 mg/kg or ~90 mg/kg of famciclovir or placebo PO q12h for 7 days, or were untreated. Swabs were collected from ventral conjunctival fornices prior to (day 1) and immediately after (day 8) the treatment period. Microbiota analysis was conducted on 124 randomly selected swabs from healthy (56 swabs) or URD-affected (68 swabs) cats. Following DNA extraction and amplification of the V4 region of the 16S rRNA gene, sequences were assembled into operational taxonomic units (OTUs). Over-represented OTUs (as determined by linear discriminate analysis effect size), alpha and beta diversity, and median relative abundance of known feline ocular surface pathogens were assessed for the entire population and in 10 clinically relevant subpopulations of cats.

Results: Bacteria from 33 phyla and 70 genera were identified. Considering all cats, median relative abundance of increased from day 1 to day 8, while Proteobacteria decreased. Community membership and structure (beta diversity) differed between days 1 and 8 for all famciclovir-treated cats (regardless of health status or dose) and healthy or URD-affected cats (regardless of famciclovir dose). Differences in taxonomic diversity within a sample (alpha diversity) between day 1 and day 8 were not detected in any subpopulations.

Conclusions And Relevance: Within 1 week of shelter entry, there were significant changes in community structure and membership of the feline conjunctival microbiota, with a shift towards over-representation of feline ocular surface pathogens. Although famciclovir may impact beta diversity of the feline conjunctival microbiota, absence of change in alpha diversity suggests minimal shift in individual cats.
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http://dx.doi.org/10.1177/1098612X20949038DOI Listing
August 2020

Preliminary report of postoperative complications of phacoemulsification in Pugs: A multicenter retrospective study of 32 cases.

Vet Ophthalmol 2020 May 11;23(3):442-449. Epub 2020 Mar 11.

Animal Eye Clinic, Denmark, WI, USA.

Objective: To compare complication rates and visual outcomes following phacoemulsification in Pugs versus dogs of other breeds.

Animals Studied: Thirty-two pure-bred Pugs (55 eyes) and 32 dogs of other breeds (56 eyes) undergoing phacoemulsification.

Procedures: Multi-institutional retrospective medical record review of perioperative factors, postoperative complications, and visual outcomes. The reference population of dogs of varying breeds included surgical cases following each Pug case at the same institutions. Perioperative risk factors and postoperative complication rates were compared between the two populations.

Results: Pigmentary keratitis and diabetes mellitus were the most common preoperative comorbidities, found in 75% (P < .001) and 72% (P = .12) of Pugs, respectively. No perioperative factors were significantly associated with postoperative complications in Pugs. Postoperative complication rates were similar between groups; however, the most common complication in Pugs was corneal ulceration (15% of operated eyes), whereas glaucoma was most common in the reference population (13% of operated eyes). Three months postoperatively, vision was preserved in 91% of eyes of Pugs (50/55) and 95% of the reference population (53/56). One year postoperatively, 80% (32/40) of Pug eyes and 82% (28/34) of eyes in the reference population remained sighted.

Conclusions: Comorbidities and complications of cataract surgery in Pugs of this study demonstrate a predisposition for corneal disease. This highlights the importance of preoperative evaluation of factors associated with PK and corneal clarity, and postoperative monitoring for corneal ulceration in this breed.
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http://dx.doi.org/10.1111/vop.12739DOI Listing
May 2020

Effects of famciclovir in cats with spontaneous acute upper respiratory tract disease.

J Feline Med Surg 2020 06 27;22(6):492-499. Epub 2019 Jun 27.

Department of Veterinary Medicine and Epidemiology, University of California, Davis, CA, USA.

Objectives: The aim of this study was to assess the effects of famciclovir administration in cats with spontaneously acquired acute upper respiratory tract disease.

Methods: Twenty-four kittens with clinical signs of acute upper respiratory tract disease were randomly allocated to receive doxycycline (5 mg/kg PO q12h) alone (group D; n = 12) or with famciclovir (90 mg/kg PO q12h; group DF; n = 12) for up to 3 weeks. Clinical disease severity was scored at study entry and daily thereafter. Oculo-oropharyngeal swabs collected at study entry and exit were assessed using quantitative PCR for nucleic acids of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), and .

Results: The median (range) age of cats was 1.5 (1-6) months in group D vs 1.6 (1-5) months in group DF ( = 0.54). Pathogens detected in oculo-oropharyngeal swabs at study entry included FCV (n = 13/24; 54%), (n = 8/24; 33%), FHV-1 (n = 7/24; 29), (n = 7/24; 29%) and (n = 3/24; 12%). Median (range) duration of clinical signs was 11.5 (3-21) days in group DF and 11 (3-21) days in group D ( = 0.75). Median (range) total disease score at the end of the study did not differ between groups (group D 1 [1-1] vs group DF 1 [1-3]; = 0.08).

Conclusions And Relevance: This study revealed no significant difference in response to therapy between cats treated with doxycycline alone or with famciclovir; cats improved rapidly in both groups. However, identification of FHV-1 DNA was relatively uncommon in this study and clinical trials focused on FHV-1-infected cats are warranted to better evaluate famciclovir efficacy.
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http://dx.doi.org/10.1177/1098612X19857587DOI Listing
June 2020

Evaluation of the major histocompatibility complex (MHC) class II as a candidate for sudden acquired retinal degeneration syndrome (SARDS) in Dachshunds.

Vet Ophthalmol 2019 Nov 21;22(6):751-759. Epub 2019 Feb 21.

Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California.

Objective: Sudden acquired retinal degeneration syndrome (SARDS) is one of the leading causes of acute blindness in dogs, with an unknown etiology and no effective treatment. Certain breeds such as Dachshunds are overrepresented among SARDS patients, and therefore, the syndrome is suspected to have a genetic component. The objective of this study was to determine if a genetic locus associated with SARDS in Dachshunds could be identified using a genome-wide association study (GWAS).

Procedures: Genome-wide association mapping was performed in 15 SARDS-affected and 16 unaffected Dachshunds. Genotyping of three classical DLA class II genes (DLA-DRB1, DLA-DQA1, and DLA-DQB1) was performed in 34 SARDS-affected and 66 unaffected Dachshunds to evaluate for an association in this region.

Results: Although no single nucleotide polymorphisms (SNPs) were of genome-wide statistical significance (P  < 0.05), 5 of the top 9 SNPs were in the major histocompatibility complex (MHC). Using DLA typing, the allele DLA-DRB1*09401 was identified as a risk factor for the development of SARDS (P = 0.0032, OR = 4.0). The alleles DLA-DQB1*00101 (P = 0.0050, OR = 0.31), DLA-DQA1*00901 (P = 0.0087, OR = 0.33), and a previously identified DLA-DRB1allele described as "DRB1-T" (P = 0.0284, OR = 0.37) were identified as protective factors.

Conclusions: Although far from definitive, association of SARDS with alleles of immunologic importance further supports the hypothesis that autoimmunity may play a role in the pathogenesis of SARDS.
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http://dx.doi.org/10.1111/vop.12646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6703976PMC
November 2019

Pilot Study of the Safety and Tolerability of a Subconjunctival Penciclovir Implant in Cats Experimentally Infected with Herpesvirus.

J Ocul Pharmacol Ther 2019 Jan/Feb;35(1):38-49. Epub 2018 Dec 18.

1 Department of Surgical and Radiological Sciences, University of California-Davis, Davis, California.

Purpose: To assess safety and tolerability of a subconjunctival penciclovir implant in cats infected with feline herpesvirus type 1 (FHV-1).

Methods: Subconjunctival blank (n = 4 cats) or penciclovir-impregnated (n = 6) silicone implants were placed bilaterally in 10 normal, FHV-1-naive cats 7-8 days before viral inoculation. Outcomes included disease score, FHV-1 serology, conjunctival viral load, Schirmer tear tests (STT), tear film break-up times (TFBUTs), conjunctival histology, goblet cell density (GCD), body weight, tear and plasma penciclovir concentration, and corneal ulcer evaluation.

Results: Both groups had similar clinical and histologic disease scores, STT values, TFBUTs, GCD, FHV-1 titers, viral loads, and body weight changes. No ocular or systemic signs of toxicity were noted. Tear penciclovir concentration varied widely among cats and across time points. Tear penciclovir concentrations exceeded the lowest published half maximal inhibitory concentration (IC) in 5/6 treated cats. Plasma penciclovir concentrations remained below 10 ng/mL. Cats with higher tear penciclovir concentrations at inoculation and/or time of peak disease had fewer corneal ulcers than cats in which tear penciclovir concentrations were inconsistent, low, or unrecordable.

Conclusions: Subconjunctival blank and penciclovir-impregnated implants were well tolerated at the ocular surface and not associated with systemic toxicity, adverse effect, or appreciable plasma penciclovir concentrations. Tear penciclovir concentrations >IC were sometimes achieved, especially during burst release soon after implant placement. Further study is necessary to determine efficacy of locally delivered penciclovir when penciclovir concentration is consistently maintained above IC. This will be especially useful in patients unable to receive systemic therapy.
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http://dx.doi.org/10.1089/jop.2018.0043DOI Listing
July 2020

Clinical features of cats with aqueous tear deficiency: a retrospective case series of 10 patients (17 eyes).

J Feline Med Surg 2019 10 12;21(10):944-950. Epub 2018 Nov 12.

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.

Objectives: The aim of this study was to describe the clinical findings, diagnostic test results and response to therapy of cats with Schirmer tear test 1 (STT-1) values below the reference interval.

Methods: The medical records of three institutions were searched for cats with ocular surface disease and STT-1 values <9 mm/min, confirmed at two or more separate visits.

Results: Ten cats (17 eyes) were included. The mean ± SD (range) age and STT-1 values in affected eye(s) were 6.1 ± 5.7 (0.2-16) years and 2.4 ± 3.1 (0-8) mm/min, respectively. Concurrent ocular surface disease was bilateral in 5/10 cats. Clinical signs included conjunctivitis (14/17 eyes), corneal ulceration (6/17 eyes), non-ulcerative keratitis (4/17 eyes), symblepharon (4/17 eyes), eosinophilic keratitis (3/17 eyes), corneal sequestrum (3/17 eyes), corneal fibrosis (2/17 eyes) and meibomitis (2/17 eyes). Management included: topically applied lacrimomimetics, antiviral drugs, corticosteroids or immunomodulatory drugs; orally administered famciclovir; or surgical procedures, in various combinations. Response to therapy (defined as an increase in STT-1 value of ⩾5 mm/min) was transient (seen at a single reassessment) in 65% of eyes and sustained (seen at ⩾2 consecutive reassessments) in 18% of eyes.

Conclusions And Relevance: Clinical features seen in cats with low STT-1 values are described, although the association between aqueous deficiency and the reported ocular changes is unknown at this time. We encourage clinicians to assess the tear film in cats with ocular surface disease, and initiate therapy with lacrimomimetics if STT-1 values are repeatedly below normal. Such information will further define aqueous tear deficiency in cats, providing a better understanding of disease prevalence, pathogenesis and treatment.
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http://dx.doi.org/10.1177/1098612X18810867DOI Listing
October 2019

Effect of topical application of 0.5% proparacaine on corneal culture results from 33 dogs, 12 cats, and 19 horses with spontaneously arising ulcerative keratitis.

Vet Ophthalmol 2019 Jul 7;22(4):415-422. Epub 2018 Sep 7.

Department of Surgical and Radiological Sciences, University of California, Davis, California.

Objective: To investigate the effect of topically applied proparacaine on bacterial and fungal culture results and to compare cytologic and culture results in patients with ulcerative keratitis.

Procedure: Corneal samples were collected from 33 dogs, 19 horses, and 12 cats with spontaneously arising ulcerative keratitis. Samples for bacterial (dogs, cats, horses) and fungal (horses) cultures were collected prior to and following application of 0.5% proparacaine or saline. All patients then received a topical anesthetic, and samples were collected for cytology. Frequency of cultivatable bacteria before (Swab 1) and after (Swab 2) application of proparacaine or saline was compared using Fisher's exact test. Homogeneity of culture and cytology results was assessed using McNemar's test.

Results: No difference was detected in number of animals from which bacteria were isolated from Swab 1 or Swab 2 for proparacaine (21/37 and 17/37, respectively) or saline (10/27 and 12/27, respectively). Small numbers prevented analysis of fungal culture results in horses between Swab 1 and Swab 2 for proparacaine (2/12 and 1/12, respectively) or saline (both, 1/8). Bacteria were isolated from 10 of 20 horses and detected cytologically in 3 of these; fungi were isolated from 3 of 20 horses and detected cytologically in 2 of these. Bacteria were detected more frequently using culture (31/64) than cytology (19/64).

Conclusion: Proparacaine did not significantly alter bacterial or fungal culture results in cats, dogs, or horses; however, clinical significance warrants investigation. Culture and cytology provided complementary data; both should be performed to maximize organism detection in patients with ulcerative keratitis.
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http://dx.doi.org/10.1111/vop.12604DOI Listing
July 2019

Prophylactic and therapeutic effects of twice-daily famciclovir administration on infectious upper respiratory disease in shelter-housed cats.

J Feline Med Surg 2019 06 13;21(6):544-552. Epub 2018 Aug 13.

2 Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA.

Objectives: In humans with herpetic disease, early or pre-emptive famciclovir therapy reduces disease duration and severity. This prospective, masked, placebo-controlled study tested therapeutic and prophylactic effects of two famciclovir doses given to cats for 7 days following shelter entry.

Methods: Cats were assigned to prophylactic or therapeutic study arms based on clinical evidence of herpetic disease at study entry. Cats in the therapeutic arm received no treatment (n = 19), placebo (lactose; n = 18) or famciclovir at ~30 (n = 21) or ~90 mg/kg (n = 20) PO q12h for 7 days. Cats in the prophylactic arm received no treatment (n = 25) or famciclovir at ~30 (n = 28) or ~90 mg/kg (n = 27) PO q12h for 7 days. Disease scores, body weight, conjunctival feline herpesvirus 1 (FHV-1) shedding, and adoption rates were recorded on days 1 (admission), 8 (end of therapy) and 15 (1 week after cessation of therapy).

Results: No significant differences in clinical scores were observed among groups in the prophylactic or therapeutic arms at any of the three time points. However, within the therapeutic arm, viral shedding on day 8 was significantly higher in cats receiving no treatment than in those receiving ~30 or ~90 mg/kg famciclovir, and this effect persisted 1 week after famciclovir was stopped (day 15) only in cats receiving ~30 mg/kg, although this approached significance in cats receiving ~90 mg/kg. No significant differences in adoption rates were detected among groups in either arm throughout the study.

Conclusions And Relevance: Although we did not demonstrate a statistically or clinically significant effect of famciclovir administration upon clinical signs of infectious upper respiratory disease or adoption, when it was administered at ~30 or ~90 mg/kg q12h for 1 week famciclovir reduced conjunctival FHV-1 shedding. This suggests a potential role in interrupting the infectious cycle within a shelter population; however, cost in time and resources, and stress and pathogen transmission induced by oral administration should be considered.
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http://dx.doi.org/10.1177/1098612X18789719DOI Listing
June 2019

A multidisciplinary, minimally invasive approach combining lacrimoscopy and fluoroscopically guided stenting for management of nasolacrimal apparatus obstruction in dogs.

J Am Vet Med Assoc 2018 Jun;252(12):1527-1537

OBJECTIVE To describe and evaluate outcomes of a multidisciplinary, minimally invasive approach combining lacrimoscopy and fluoroscopically guided stenting for management of nasolacrimal apparatus (NLA) obstruction in dogs. DESIGN Prospective, nonrandomized clinical trial. ANIMALS 16 client-owned dogs with confirmed NLA obstruction. PROCEDURES Dogs underwent CT contrast dacryocystorhinography, rhinoscopy, and lacrimoscopy. Whenever possible, the NLA was stented, typically with fluoroscopic guidance. RESULTS Median duration of clinical signs prior to treatment was 3.2 months (range, 0.2 to 14 months). Causes of NLA obstruction were a foreign body (n = 5), dacryocystitis (4), stenosis secondary to fibrosis (3), granulation tissue (1), or granulation tissue in association with a small foreign body (1); a cause was not identified in 2 dogs. Stents were placed in 14 of 16 (88%) dogs for a median duration of 5.6 weeks (range, 1.3 to 9.4 weeks). Stenting was not possible in 2 dogs with stenosis of the NLA secondary to granulation tissue or fibrosis. Owners of all 16 dogs reported at least 60% clinical improvement with median improvement rated as 95%, and owners of 8 dogs reporting complete resolution of signs. Two dogs required antimicrobial administration because of dacryocystitis that persisted after stent removal; a foreign body was not found in either dog. CONCLUSIONS AND CLINICAL RELEVANCE Overall clinical response and owner-rated improvement for dogs with NLA obstruction that underwent lacrimoscopy and fluoroscopically guided stenting were high, especially given that these dogs had failed to respond to conventional treatment.
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http://dx.doi.org/10.2460/javma.252.12.1527DOI Listing
June 2018

Medical management of deep ulcerative keratitis in cats: 13 cases.

J Feline Med Surg 2019 04 16;21(4):387-393. Epub 2018 May 16.

2 Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.

Case Series Summary: Described are 13 cats diagnosed with deep ulcerative keratitis and successfully managed medically without grafting procedures. Typical treatment involved frequent topical application of serum and antibiotics (usually a fluoroquinolone and a cephalosporin). Seven cats also received systemic antibiotics. Analgesia was achieved using various combinations of topical atropine and systemic buprenorphine, robenacoxib or corticosteroids. Six cats were hospitalized for a median (range) period of 2.5 (1-8) days, typically because of frequent medication administration. Median (range) follow-up time was 41.5 (9-103) days. Median (range) number of recheck examinations was 4 (2-6). Median (range) time to corneal re-epithelialization was 21 (9-103) days. Median (range) topical antibiotic course was 29.5 (16-103) days. Median (range) duration of Elizabethan collar use was 28 (13-73) days. At the time of writing, no further recheck examinations were recommended for 10 cats; median (range) time between initial to final examinations in these cats was 35 (20-103) days. All cats retained the affected globes and were apparently comfortable and visual at the latest recheck examination.

Relevance And Novel Information: These cases reveal that aggressive medical management is highly successful in select cats with deep ulcerative keratitis, and can result in a cosmetically acceptable, apparently comfortable and visual globe. However, therapy is intensive with frequent administration of multiple topical and sometimes systemic medications, and requires multiple veterinary visits over many weeks. Referral to a veterinary ophthalmologist for consideration of surgical stabilization is recommended, as not all cases may be amenable to the medical therapy described here.
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http://dx.doi.org/10.1177/1098612X18770514DOI Listing
April 2019

Retrobulbar vs peribulbar regional anesthesia techniques using bupivacaine in dogs.

Vet Ophthalmol 2019 Mar 15;22(2):183-191. Epub 2018 May 15.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.

Objective: To compare the effectiveness of retrobulbar anesthesia (RBA) and peribulbar anesthesia (PBA) in dogs.

Animal Studied: Six adult mixed-breed dogs (18-24 kg).

Procedures: In a randomized, masked, crossover trial with a 10-day washout period, each dog was sedated with intravenously administered dexmedetomidine and administered 0.5% bupivacaine:iopamidol (4:1) as RBA (2 mL via a ventrolateral site) or PBA (5 mL divided equally between ventrolateral and dorsomedial sites). The contralateral eye acted as control. Injectate distribution was evaluated by computed tomography. Following intramuscularly administered atipamezole, corneal and periocular skin sensation, intraocular pressure (IOP), and ocular reflexes, and appearance were evaluated for 24 hours. Comparisons were performed with mixed-effects linear regression (IOP) or the exact Wilcoxon signed rank test (scores). Significance was set at P ≤ .05.

Results: Injectate distribution was intraconal in 2/6 RBA- and 4/6 PBA-injected eyes. Eyes undergoing PBA had significantly reduced lateral, ventral, and dorsal periocular skin sensation for 2-3 hours, and significantly reduced corneal sensitivity for 4 hours, relative to control eyes. Chemosis and exophthalmos occurred in 33%-40% of eyes undergoing RBA and 83%-100% eyes undergoing PBA but resolved within 14 hours. Anterior uveitis developed in 2/6 and 1/6 eyes of RBA and PBA, respectively, of them corneal ulcer developed in one eye of each treatment. Both resolved 1-3 days following medical treatment.

Conclusions: Peribulbar injection produced notable anesthesia more reliably than did retrobulbar injection. Both techniques may produce adverse effects, although the uveitis/ulcer could have resulted from the contrast agent used.
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http://dx.doi.org/10.1111/vop.12579DOI Listing
March 2019

Multiple ocular developmental defects in four closely related alpacas.

Vet Ophthalmol 2018 Sep 1;21(5):544-551. Epub 2018 Mar 1.

The College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80528, USA.

Objective: To describe the clinical, gross pathologic, and histopathologic findings for a visually impaired 5.8-year-old female alpaca with multiple ocular abnormalities, as well as the clinical findings for three closely related alpacas.

Animals Studied: Four alpacas.

Procedures: Ophthalmic examination was performed on a 16-month-old female alpaca following observation of visual impairment while hospitalized for an unrelated illness. Following acute systemic decline and death 4.5 years later, the alpaca's brain, optic nerves, and eyes were examined grossly and histologically. Ophthalmic examination of three closely related alpacas was subsequently performed.

Results: The 16-month-old female alpaca (Alpaca 1) had ophthalmoscopic findings suggestive of a coloboma or hypoplasia of the retinal pigment epithelium (RPE) and choroid, and suspected optic nerve hypoplasia OU. Histopathology performed 4.5 years later revealed moderate to severe choroidal, RPE, and retinal hypoplasia with multifocal retinal detachments OU. However, the optic nerves were normal in size and histologic appearance when compared to an age-matched control. Clinical evaluation of the 2-year-old son of Alpaca 1 revealed iris colobomata OU and choroidal dysplasia/hypoplasia OD in addition to nonpathologic variations in melanin density including heterochromia iridis and a subalbinotic fundus OU. Clinical evaluation of the 13-year-old mother of Alpaca 1 revealed heterochromia iridis, cataracts, and a subalbinotic fundus OU. A 2-year-old half-brother of Alpaca 1 had an RPE and choroidal coloboma OS.

Conclusion: The developmental ocular abnormalities diagnosed in these closely related alpacas are likely hereditary.
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http://dx.doi.org/10.1111/vop.12540DOI Listing
September 2018

Clinical findings and normative ocular data for free-living Anna's (Calypte anna) and Black-chinned (Archilochus alexandri) Hummingbirds.

Vet Ophthalmol 2019 Jan 20;22(1):13-23. Epub 2018 Feb 20.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA.

Objective: To estimate the prevalence of ocular disease and obtain normative ocular data for free-living hummingbirds.

Animals Studied: Two hundred and sixty-three free-living, adult Hummingbirds from coastal and inland central California were studied, including Anna's (Calypte anna, n = 186) and Black-chinned (Archilochus alexandri; n = 77) hummingbirds.

Procedures: Slit lamp biomicroscopy and indirect ophthalmoscopy were performed on all individuals. Rebound tonometry, measurement of horizontal palpebral fissure length, and streak retinoscopy were performed on select individuals. Five conscious Anna's Hummingbirds underwent ocular imaging including fundus photography, digital slit lamp photography, and anterior segment and retinal optical coherence tomography.

Results: The prevalence of ocular disease in this population was 2.28%. Ocular imaging revealed a thin cornea, shallow anterior chamber, large lens, and a single central, deep convexiclivate fovea. Mean ± SD intraocular pressure was 11.21 ± 2.23 mm Hg. Mean ± SD eyelid length was 2.59 ± 0.19 mm. All eyes were emmetropic or mildly hyperopic with a mean (range) ± SD refractive error of +0.32 (-0.25 to +1) ± 0.33 diopters.

Conclusions: Consistent with previous reports, these data suggest that hummingbirds have visual characteristics found in predatory and prey species, as well as a low prevalence of spontaneous ocular disease. This work provides a set of reference values and clinical findings that can be used in the future research on hummingbird vision and ocular disease. It also provides representative diagnostic images of normal birds and demonstrates that advanced ocular imaging can be performed on manually restrained hummingbirds without pharmacologic dilation.
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http://dx.doi.org/10.1111/vop.12560DOI Listing
January 2019

Feline dry eye syndrome of presumed neurogenic origin: a case report.

JFMS Open Rep 2018 Jan-Jun;4(1):2055116917746786. Epub 2018 Jan 2.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA.

Case Summary: A 14-year-old female spayed Abyssinian cat, which about 1 year previously underwent thoracic limb amputation, radiotherapy and chemotherapy for an incompletely excised vaccine-related fibrosarcoma, was presented for evaluation of corneal opacity in the left eye (OS). The ocular surface of both eyes (OU) had a lackluster appearance and there was a stromal corneal ulcer OS. Results of corneal aesthesiometry, Schirmer tear test-1 (STT-1) and tear film breakup time revealed corneal hypoesthesia, and quantitative and qualitative tear film deficiency OU. Noxious olfactory stimulation caused increased lacrimation relative to standard STT-1 values suggesting an intact nasolacrimal reflex. Various lacrimostimulants were administered in succession; namely, 1% pilocarpine administered topically (15 days) or orally (19 days), and topically applied 0.03% tacrolimus (47 days). Pilocarpine, especially when given orally, was associated with notable increases in STT-1 values, but corneal ulceration remained/recurred regardless of administration route, and oral pilocarpine resulted in gastrointestinal upset. Tacrolimus was not effective. After 93 days, the cat became weak and lame and a low thyroxine concentration was detected in serum. The cat was euthanized and a necropsy performed. Both lacrimal glands were histologically normal, but chronic neutrophilic keratitis and reduced conjunctival goblet cell density were noted OU.

Relevance And Novel Information: The final diagnosis was dry eye syndrome (DES) of presumed neurogenic origin, associated with corneal hypoesthesia. This report reinforces the importance of conducting tearfilm testing in cats with ocular surface disease, as clinical signs of DES were different from those described in dogs.
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http://dx.doi.org/10.1177/2055116917746786DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5753927PMC
January 2018

Cofactors associated with Sudden Acquired Retinal Degeneration Syndrome: 151 dogs within a reference population.

Vet Ophthalmol 2018 May 27;21(3):264-272. Epub 2017 Aug 27.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA.

Objective: To determine factors associated with sudden acquired retinal degeneration syndrome (SARDS) diagnosed within one referral population.

Animals Studied: 151 dogs diagnosed with SARDS.

Procedures: Breed, age, sex, and body weight were compared between dogs with electroretinogram-confirmed SARDS and dogs presented to the UC Davis Veterinary Medical Teaching Hospital (UCD-VMTH) from 1991 to 2014.

Results: SARDS was diagnosed in 151 dogs, representing 1.3% of dogs presented to the UCD-VMTH for ophthalmic disease. Although dogs of 36 breeds were affected, the Dachshund (n = 31, 21%), Schnauzer (16, 11%), Pug (11, 7%), and Brittany (5, 3%) were significantly overrepresented, and the Labrador Retriever (3, 2%) was significantly underrepresented vs. the reference population (P < 0.001). Median (range) age and body weight of affected vs. reference dogs were 8.9 (3-20) vs. 6.8 (0.1-26) years and 12.4 (2.8-52.7) vs. 22.3 (0.1-60) kg, respectively. Dogs 6-10 years of age and between 10-20 kg in body weight were significantly overrepresented in the SARDS population, while dogs <6 years of age were significantly underrepresented (P < 0.01). Spayed females (59% of affected dogs) were significantly overrepresented compared to the reference population, whereas intact females (1% of affected dogs) were significantly underrepresented.

Conclusions: Consistent with previous studies, smaller, middle-aged, spayed female dogs may be at increased risk of developing SARDS. Unlike previous studies, this is the first study comparing a variety of SARDS-affected breeds to a reference population. Potentially increased risk of SARDS in several breeds, particularly Dachshunds, suggests a familial factor that warrants further investigation using genetic techniques.
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http://dx.doi.org/10.1111/vop.12504DOI Listing
May 2018

A comparison of retrobulbar and two peribulbar regional anesthetic techniques in dog cadavers.

Vet Anaesth Analg 2017 Jul 13;44(4):925-932. Epub 2017 Apr 13.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.

Objective: To compare injectate distribution and likelihood of regional anesthesia to the orbit following retrobulbar (RB) or peribulbar (PB) injections in dog cadavers.

Study Design: Randomized, masked study.

Animals: Twenty-four dog cadavers (aged 5.5-17 years, 2.0-36.3 kg).

Methods: Orbits underwent one of three injection techniques with bupivacaine 0.5% and iohexol (1:1): ventrolateral RB injection (1-2 mL; 15 orbits), medial canthal PB injection (2-8 mL; PB-1; 16 orbits), or dorsomedial and ventrolateral PB injections (each 1-4 mL; PB-2; 16 orbits). The likelihood of successful regional anesthesia was estimated based on computed tomographic images scored for injectate volume of distribution at the base and within the extraocular muscle cone (EOMC), and injectate distribution around the optic nerve. Intraocular pressure (IOP) was measured before and after injections. Mixed-effects linear regression with post hoc Bonferroni contrast adjustments was performed. Significance was set at 0.05.

Results: A difference in injectate volume of distribution within or at the base of the EOMC was not detected among groups. The median optic nerve circumference of injectate distribution was significantly higher in the RB injected group than in the PB-2 group. Injectate distribution following RB, PB-1 and PB-2 injections was graded as likely to provide regional anesthesia within the EOMC in 40%, 19% and 31% of eyes, and at the EOMC base in 60%, 63% and 50% of eyes, respectively. The probability of likelihood to provide regional anesthesia was lower in dogs of higher body weights. The IOP was significantly higher than baseline following PB-1 (18 ± 14 mmHg) and in comparison with RB (2 ± 3 mmHg), but not different from PB-2 injection (10 ± 11 mmHg).

Conclusions And Clinical Relevance: None of the techniques reliably produced 'successful' injectate distribution based on this study's definitions; however, clinical assessment of anesthetic success is required.
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http://dx.doi.org/10.1016/j.vaa.2017.02.009DOI Listing
July 2017

Effects of topically applied heterologous serum on reepithelialization rate of superficial chronic corneal epithelial defects in dogs.

J Am Vet Med Assoc 2017 May;250(9):1014-1022

OBJECTIVE To assess the effects of topical application of undiluted heterologous serum on time to corneal reepithelialization in dogs with superficial chronic corneal epithelial defects (SCCEDs). DESIGN Multicenter, randomized, double-masked, controlled clinical trial. ANIMALS 41 client-owned dogs. PROCEDURES After collection of baseline clinical and historical data, dogs were randomly assigned to receive topically applied undiluted heterologous serum (n = 22) or isotonic saline (0.9% NaCl) solution (19) along with tobramycin and atropine. Epithelial debridement (at all visits) and grid keratotomy (at visits 2, 3, and 4) of SCCEDs were performed. Ophthalmic examination including fluorescein application was performed once weekly for 4 weeks or until corneal reepithelialization. Clinicians and owners were masked to treatment group. RESULTS No differences in baseline data were detected between treatment groups. No difficulties with medication administration, noncompliance, or adverse reactions were noted. All SCCEDs in both groups healed by 4 weeks after treatment began. Median time to reepithelialization (2 weeks) was not significantly different between serum-treated and placebo-treated eyes. Irrespective of treatment group, median time to reepithelialization was not significantly different for Boxers versus non-Boxer breeds. Direct correlations were detected between time to reepithelialization and vascularization score at study entry, vascularization score at time of reepithelialization, and ulcer area at study entry in both groups. Time to reepithelialization was not correlated with age, sex, or duration of signs in either group. CONCLUSIONS AND CLINICAL RELEVANCE Topical application of undiluted heterologous serum was well tolerated by dogs with SCCEDs but, as an adjunct to standard treatment, did not reduce time to corneal reepithelialization.
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http://dx.doi.org/10.2460/javma.250.9.1014DOI Listing
May 2017

Assessment of tear film osmolarity using the TearLab osmometer in normal dogs and dogs with keratoconjunctivitis sicca.

Vet Ophthalmol 2017 Jul 20;20(4):357-364. Epub 2016 Oct 20.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.

Objective: To evaluate repeatability and reproducibility of tear osmolarity measured using the TearLab osmometer in normal dogs and to assess its diagnostic potential in dogs with keratoconjunctivitis sicca (KCS).

Animals Studied: Beagle dogs; six normal and five with KCS.

Procedures: Tear osmolarity and Schirmer tear test-1 (STT-1) values were obtained at various times. Normal dogs were assessed for diurnal variation and repeatability and reproducibility of measurements. Dogs with KCS were evaluated before and after 5 months' topical twice-daily therapy with 2% cyclosporine.

Results: Mean ± SD tear osmolarity (mOsm/L) was significantly higher in normal dogs (337.4 ± 16.2) than in dogs with KCS before therapy (306.2 ± 18.0; P < 0.0001), but not following therapy with 2% cyclosporine (330.5 ± 13.7; P = 1.00). Osmolarity readings lower than 325.5 mOsm/L were suggestive of KCS (84.8% sensitivity and 87.1% specificity). In normal dogs, tear osmolarity readings were stable during the daytime (P = 0.99). Repeated measurements revealed high variability and typically poor-to-moderate repeatability and reproducibility, although this was improved by taking three successive measurements at each session. Considering combined data from all dogs, a positive correlation existed between STT-1 and tear osmolarity measurements (Pearson's correlation test, P = 0.04, r = 0.62).

Conclusions: Canine tear osmolarity as determined by TearLab osmometer was variable, required multiple readings to be informative, and differed from values reported for humans. Dogs with KCS had a lower tear osmolarity than did normal dogs, and this increased following cyclosporine therapy.
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http://dx.doi.org/10.1111/vop.12436DOI Listing
July 2017

Oral administration of famciclovir for treatment of spontaneous ocular, respiratory, or dermatologic disease attributed to feline herpesvirus type 1: 59 cases (2006-2013).

J Am Vet Med Assoc 2016 Sep;249(5):526-38

OBJECTIVE To evaluate outcomes for cats treated with orally administered famciclovir 3 times/d for clinical signs attributed to naturally occurring feline herpesvirus type 1 (FHV-1) infection and to assess variables related to owner satisfaction with the treatment. DESIGN Retrospective case series. ANIMALS 59 client-owned cats. PROCEDURES Medical records were reviewed to identify cats treated for presumed FHV-1 infection from 2006 through 2013 with ≥ 1 follow-up visit. Signalment, duration of clinical signs, prior treatment, examination findings, diagnostic test results, concurrent treatments, and outcome data were recorded. Owners were asked to complete a survey regarding patient- and treatment-related variables. Data were compared between cats that received low (approx 40 mg/kg [18 mg/lb]) and high (approx 90 mg/kg [41 mg/lb]) doses of famciclovir, PO, 3 times/d. RESULTS Patient age ranged from 0.03 to 16 years. Conjunctivitis (51/59 [86%]), keratitis (51 [86%]), blepharitis (19 [32%]), nasal discharge or sneezing (10 [17%]), and dermatitis (4 [7%]) were common findings. Clinical improvement was subjectively graded as marked in 30 (51%) cats, mild in 20 (34%), and nonapparent in 9 (15%). Median time to improvement was significantly shorter, and degree of improvement was significantly greater in the highdose group than in the low-dose group. Adverse effects potentially attributable to famciclovir administration were reported for 10 cats. On the basis of survey responses, most (29/32 [91%]) owners were satisfied with their cat's treatment. CONCLUSIONS AND CLINICAL RELEVANCE Famciclovir at the prescribed dosages was associated with improved clinical signs in cats with presumed FHV-1 infection, and few adverse effects were attributed to the treatment. Further studies are needed to assess whether a famciclovir dosage of 90 versus 40 mg/kg, PO, 3 times/d would result in increased efficacy and shorter treatment time.
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http://dx.doi.org/10.2460/javma.249.5.526DOI Listing
September 2016

Utility of antigen testing for the diagnosis of ocular histoplasmosis in four cats: a case series and literature review.

J Feline Med Surg 2017 Oct 15;19(10):1110-1118. Epub 2016 Aug 15.

6 Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.

Case series summary This case series describes the clinical utility of antigen testing for the diagnosis of feline ocular histoplasmosis. Four cats with suspected (n = 2) or confirmed (n = 2) ocular histoplasmosis are described: three from Oklahoma and one from California. In one case, serial urine antigen tests, as well as a serum antigen test for Histoplasma capsulatum, were negative; however, light microscopy identified microorganisms consistent with H capsulatum in ocular tissues at necropsy. In a further two cats with recurrent ocular histoplasmosis following long-term systemic antifungal therapy, Histoplasma species urine antigen concentrations were negative, but both cats improved clinically following systemic antifungal therapy and remained in apparent clinical remission after treatment cessation (9-16 months). The final cat displayed profound bilateral endophthalmitis; however, Histoplasma species antigen testing of vitreous humor and subretinal fluid from the left eye was negative. Intralesional organisms were detected on histopathology of both eyes, and H capsulatum was subsequently isolated and sequenced from tissue of one eye. Relevance and novel information These cases highlight the potential difficulty in definitively diagnosing ocular histoplasmosis in cats when conducting antigen testing of serum, urine and even ocular fluids. Although antigen testing has previously proven useful in the diagnosis of disseminated feline histoplasmosis, it may not be adequate in cats with only ocular signs.
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http://dx.doi.org/10.1177/1098612X16662310DOI Listing
October 2017

Pharmacokinetic modeling of penciclovir and BRL42359 in the plasma and tears of healthy cats to optimize dosage recommendations for oral administration of famciclovir.

Am J Vet Res 2016 Aug;77(8):833-45

OBJECTIVES To determine, following oral administration of famciclovir, pharmacokinetic (PK) parameters for 2 of its metabolites (penciclovir and BRL42359) in plasma and tears of healthy cats so that famciclovir dosage recommendations for the treatment of herpetic disease can be optimized. ANIMALS 7 male domestic shorthair cats. PROCEDURES In a crossover study, each of 3 doses of famciclovir (30, 40, or 90 mg/kg) was administered every 8 or 12 hours for 3 days. Six cats were randomly assigned to each dosage regimen. Plasma and tear samples were obtained at predetermined times after famciclovir administration. Pharmacokinetic parameters were determined for BRL42359 and penciclovir by compartmental and noncompartmental methods. Pharmacokinetic-pharmacodynamic (PK-PD) indices were determined for penciclovir and compared among all dosage regimens. RESULTS Compared with penciclovir concentrations, BRL42359 concentrations were 5- to 11-fold greater in plasma and 4- to 7-fold greater in tears. Pharmacokinetic parameters and PK-PD indices for the 90 mg/kg regimens were superior to those for the 30 and 40 mg/kg regimens, regardless of dosing frequency. Penciclovir concentrations in tears ranged from 18% to 25% of those in plasma. Administration of 30 or 40 mg/kg every 8 hours achieved penciclovir concentrations likely to be therapeutic in plasma but not in tears. Penciclovir concentrations likely to be therapeutic in tears were achieved only with the two 90 mg/kg regimens. CONCLUSIONS AND CLINICAL RELEVANCE In cats, famciclovir absorption is variable and its metabolism saturable. Conversion of BRL42359 to penciclovir is rate limiting. The recommended dosage of famciclovir is 90 mg/kg every 12 hours for cats infected with feline herpesvirus.
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http://dx.doi.org/10.2460/ajvr.77.8.833DOI Listing
August 2016

Gross, histologic, and computed tomographic characterization of nonpathological intrascleral cartilage and bone in the domestic goat (Capra aegagrus hircus).

Vet Ophthalmol 2017 May 2;20(3):214-221. Epub 2016 Jun 2.

Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA.

Objective: To characterize grossly, histologically, and via computed tomography (CT) the appearance of intrascleral cartilage, bone, or both in domestic goats with otherwise normal eyes and to correlate this with age, sex, and breed.

Animals Studied: Sixty-eight domestic goats (89 eyes).

Procedures: Forty-nine formalin-fixed globes from 38 goats underwent high-resolution CT, and gross and light microscopic examination. An additional 40 eyes from 30 goats underwent light microscopy only. Age, breed, and sex of affected goats were retrieved from medical records.

Results: Considering all methods of evaluation collectively, cartilage was detected in 42% of eyes (44% of goats) and bone in 11% of eyes (12% of goats); bone was never seen without cartilage. Goats in which bone, cartilage, or both were detected ranged from 0.25 to 13 (median = 3.5) years of age, represented 11 of 12 breeds of the study population, and had a male:female ratio of 11:19. Bone was detected in the eyes of significantly more males (n = 8) than females (n = 2). No sex predilection was noted for cartilage alone. Histology revealed intrascleral chondrocyte-like cells, hyaline cartilage, and islands of lamellar bone. Some regions of bone had central, adipose-rich, marrow-like cavities. CT localized mineralized tissue as adjacent to or partially surrounding the optic nerve head.

Conclusions: This is the first report of intrascleral bone or cartilage in a normal goat and of intrascleral bone in an otherwise normal mammal. The high prevalence of intrascleral cartilage and bone in this study suggests that this finding is normal and likely represents an adaptation in goats.
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http://dx.doi.org/10.1111/vop.12391DOI Listing
May 2017

A review of antiviral drugs and other compounds with activity against feline herpesvirus type 1.

Vet Ophthalmol 2016 Jul 19;19 Suppl 1:119-30. Epub 2016 Apr 19.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA.

Feline herpesvirus type 1 (FHV-1) is a common and important cause of ocular surface disease, dermatitis, respiratory disease, and potentially intraocular disease in cats. Many antiviral drugs developed for the treatment of humans infected with herpesviruses have been used to treat cats infected with FHV-1. Translational use of drugs in this manner ideally requires methodical investigation of their in vitro efficacy against FHV-1 followed by pharmacokinetic and safety trials in normal cats. Subsequently, placebo-controlled efficacy studies in experimentally inoculated animals should be performed followed, finally, by carefully designed and monitored clinical trials in client-owned animals. This review is intended to provide a concise overview of the available literature regarding the efficacy of antiviral drugs and other compounds with proven or putative activity against FHV-1, as well as a discussion of their safety in cats.
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http://dx.doi.org/10.1111/vop.12375DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930706PMC
July 2016

Whole genome sequencing in cats, identifies new models for blindness in AIPL1 and somite segmentation in HES7.

BMC Genomics 2016 Mar 31;17:265. Epub 2016 Mar 31.

Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri - Columbia, E109 Vet Med Building, 1600 E. Rollins Street, Columbia, MO, 65211, USA.

Background: The reduced cost and improved efficiency of whole genome sequencing (WGS) is drastically improving the development of cats as biomedical models. Persian cats are models for Leber's congenital amaurosis (LCA), the most severe and earliest onset form of visual impairment in humans. Cats with innocuous breed-defining traits, such as a bobbed tail, can also be models for somite segmentation and vertebral column development.

Methods: The first WGS in cats was conducted on a trio segregating for LCA and the bobbed tail abnormality. Variants were identified using FreeBayes and effects predicted using SnpEff. Variants within a known haplotype block for cat LCA and specific candidate genes for both phenotypes were prioritized by the predicted variant effect on the proteins and concordant segregation within the trio. The efficiency of WGS of a single trio of domestic cats was evaluated.

Results: A stop gain was identified at position c.577C > T in cat AIPL1, a predicted p.Arg193*. A c.5A > G variant causing a p.V2A was identified in HES7. The variants segregated concordantly in a Persian - Japanese bobtail pedigree. Over 1700 cats from 40 different breeds and populations were genotyped for the AIPL1 variant, defining an allelic frequency in only Persian -related breeds of 1.15%. A sub-set of cats was genotyped for the HES7 variant, supporting the variant as private to the Japanese bobtail breed. Approximately 18 million SNPs were identified for application in cat research. The cat AIPL1 variant would have been considered a high priority variant for evaluation, regardless of a priori knowledge from previous genetic studies.

Conclusions: This study represents the first effort of the 99 Lives Cat Genome Sequencing Initiative to identify disease--causing variants in the domestic cat using WGS. The current cat reference assembly is efficient for gene and variant identification. However, as the feline variant database improves, development of cats as biomedical models for human disease will be more efficient, providing an alternative, large animal model for drug and gene therapy trials. Undiagnosed human patients with early-onset blindness should be screened for this AIPL1 variant. The HES7 variant should further calibrate the somite segmentation clock.
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http://dx.doi.org/10.1186/s12864-016-2595-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4815086PMC
March 2016

Histologic and immunohistochemical predictors of clinical behavior for feline diffuse iris melanoma.

Vet Ophthalmol 2016 Jul 24;19 Suppl 1:44-55. Epub 2016 Jan 24.

Surgical and Radiological Sciences, University of California, Davis, CA, 95616, USA.

Objective: To determine histologic and immunohistochemical predictors of metastasis of feline diffuse iris melanoma (FDIM).

Animals: Globes from 47 client-owned cats enucleated for FDIM between January 1985 and December 2013.

Procedures: Hematoxylin and eosin-stained sections were evaluated for neoplastic invasiveness and cell morphology, necrosis within the neoplasm, inflammation, and glaucoma. Sections were immunolabeled with antibodies against melan-A, PNL2, E-cadherin, or B-Raf, and label intensity, percentage of labeled cells, and label homogeneity were semi-quantitatively graded. Medical records were evaluated, and referring veterinarians and clients were contacted to determine whether cats developed metastasis following enucleation. The log-rank test or Cox proportional hazards model was used to determine associations between histologic or immunohistochemical parameters and metastasis.

Results: Metastasis was suspected or confirmed in 9/47 (19%) cats. Extrascleral extension, necrosis within the neoplasm, a mitotic index of >7 mitoses in 10 high-power (×400) fields, choroidal invasion, and increased E-cadherin and melan-A label intensity were each associated with increased rate of metastasis. PNL2 label homogeneity was associated with decreased rate of metastasis. Decreased PNL2 label intensity and an increasing percentage of neoplastic cells labeled for melan-A each approached significance for increased rate of metastasis.

Conclusions: We report four histologic and three immunohistochemical parameters helpful in determining cats at risk of metastasis of FDIM. Further studies should determine if B-Raf mutations identified in human malignant melanomas are found in cats with FDIM and assess benefits of adjunctive therapy following enucleation of eyes with FDIM bearing poor prognostic indicators.
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http://dx.doi.org/10.1111/vop.12344DOI Listing
July 2016

Goblet cell density and distribution in cats with clinically and histologically normal conjunctiva.

Vet Ophthalmol 2016 Jul 22;19 Suppl 1:38-43. Epub 2016 Jan 22.

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, 95616, CA, USA.

Objective: The aim of this study was to evaluate goblet cell density (GCD) and distribution in cats without clinical evidence of ocular surface disease and without histologic evidence of conjunctival disease.

Animals Studied: Fourteen Domestic Shorthair cats euthanized for reasons unrelated to this study.

Procedures: Before euthanasia, cats were verified using slit-lamp biomicroscopy and fluorescein staining to be free of eyelid or ocular surface abnormalities. Immediately after euthanasia, bilateral conjunctival specimens including third eyelid (TEL) were collected, routinely processed, and stained with periodic acid-Schiff and hematoxylin and eosin. Thirteen conjunctival regions were identified. For each region, GCD was expressed as the percentage of goblet cells/200 basal epithelial cells.

Results: Mean GCD ranged widely by region: anterior surface of the TEL = 48.8%, fornicial regions = 47.0%, palpebral regions = 38.5%, bulbar regions = 19.6%, and posterior surface of the TEL = 12.6%. The anterior surface of the TEL had significantly higher GCD than did the bulbar and the palpebral regions, but not the fornicial regions. Bulbar conjunctiva had significantly lower GCD than did all other conjunctival regions except the posterior surface of the TEL. No significant difference was noted between GCD of male versus female cats, dorsal versus ventral regions, or lateral versus medial regions.

Conclusions: Although conjunctival GCD ranged widely by region, the anterior surface of the TEL appears to be an excellent location for assessing conjunctival goblet cells in cats because this area has high GCD and is more readily accessible than is the palpebral, fornicial, or bulbar conjunctiva.
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http://dx.doi.org/10.1111/vop.12343DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930709PMC
July 2016