Diamond burr debridement of calcific band keratopathy in 24 eyes of 22 horses

PURPOSE

To evaluate the safety and effectiveness of diamond burr debridement (DBD) for the treatment of calcific band keratopathy (CBK) in horses.

METHODS

Medical records from horses with CBK were reviewed over a period of 4 years. Diagnosis of CBK was based on slit-lamp examination findings, and DBD was performed on standing sedated horses. Follow-up was obtained by clinical reevaluation of the treated eyes or a telephone survey with the referring veterinarian.

RESULTS

Twenty-two horses of different ages (median: 11 years; range: 5-23) representing 24 CBK-affected eyes (14 left eyes and 10 right eyes) were included in the study. The patients had a medical history of chronic and recurrent uveitis, which required repeated long-term treatments with various combinations of ophthalmic corticosteroids. DBD alone cleared the cornea in 22 affected eyes (92%), but it was combined with blade scraping in two cases with thick calcium plaques. The postoperative medication included a topical antibiotic, atropine drops, and oral flunixin meglumine. Corneal healing was achieved in 21 eyes (87%), 5-21 days (median time 13 days) postoperatively. The three remaining horses were lost to follow-up. Recurrence occurred in 5 of the 21 (24%) reexamined eyes, 3-12.5 weeks (median 8 weeks) postoperatively, and required a second DBD. Four of the 21 eyes ended up being enucleated due to sequelae of uveitis. The main limitations of the study include those inherent to all retrospective clinical data collections.

CONCLUSION

Mechanical DBD can readily and safely clear the cornea in horses with CBK, but recurrence of calcium deposition is possible.

Pyogenic granuloma of the cornea in a pony: Uncommon complication of corneal wound healing

A 6-year-old miniature Shetland pony mare was referred for evaluation of a left corneal mass, which developed from the healing tissue of a corneal traumatic ulceration that had occurred 4 weeks previously. On gross examination, a spherical, smooth-surfaced, and pink-colored lesion of about 1 cm in diameter was protruding from the left palpebral fissure. Ophthalmic examination revealed that it was attached to the scar tissue of the cornea, and that one corpora nigra was adherent to the posterior face of corneal wounded area, without sign of uveitis. The remainder of the ophthalmic examination was unremarkable. The mass was excised, and cryotherapy was used as an adjunctive therapy. Histopathology of the resected mass was consistent with a pyogenic granuloma on the basis of radially oriented proliferating capillaries, embedded in immature granulation tissue containing an infiltrate of neutrophils, plasma cells and eosinophils. There were no histological features of malignancy. 2 months after surgery, the ventral part of the fibrotic corneal scar was slightly raised by a pink tissue, suggesting possible recurrence of the initial lesion. A second cryotherapy was performed over the leukoma area. No recurrence has been noted for a follow-up period of more than 25 months. Pyogenic granuloma is a benign proliferative fibrovascular response that typically develops after trauma or surgery. Corneal involvement is rare in humans, and to the authors' knowledge has never been documented in veterinary ophthalmology.

Conjunctival calcinosis circumscripta in a dog: Treatment combining surgical resection and amniotic membrane grafting

This report describes the clinical features, histopathology, and surgical treatment of a case of conjunctival calcification in a 5-month-old female English Setter, referred with a history of recurrent conjunctivitis in the right eye (OD). The ophthalmic findings were limited to multifocal white plaques embedded in a markedly inflamed conjunctiva of the eyelids and the anterior nictitating membrane OD. Calcification was suspected. The blood cell count, blood chemical profile, and urinalysis were within normal limits, and long-bone radiographs appeared normal. After removal of the affected area by means of a large conjunctivectomy, cryopreserved canine amniotic membrane (AM) was transplanted to fill in the defect. Multifocal ectopic calcium deposits in the conjunctival lamina propria were confirmed histopathologically. The postoperative healing was uneventful, and no recurrence was observed during a follow-up period of five years. Conjunctival mineralization is uncommon in canine ophthalmology, and the cause remained undetermined in the present case, for which AM transplantation was able to promote conjunctival healing after a large surgical excision.

Corneal anesthesia associated with topical application of 2% lidocaine nonophthalmic gel to healthy canine eyes

OBJECTIVE

To assess the degree and duration of corneal anesthesia induced by topical application of 2% lidocaine gel to the healthy canine eye.

ANIMALS

Nineteen adult Beagles free of ocular abnormalities.

PROCEDURES

Baseline corneal touch threshold (CTT) was measured bilaterally with a Cochet-Bonnet aesthesiometer. The 2% lidocaine gel (0.1 mL) was applied to one eye, randomly assigned, and the same volume of a lubricant gel was applied to the opposite eye. The CTT measurements were repeated bilaterally within 1 minute, after drug application, and every 5 minutes, until the baseline corneal sensitivity was restored. The potential for local adverse effects was evaluated.

RESULTS

Complete desensitization of the cornea (CTT = 0) was achieved one minute after lidocaine gel application and was maintained during 25.3 ± 12.5 minutes. Overall, the corneal sensitivity was significantly decreased for 58.4 ± 16.6 minutes compared with baseline level. Minor and reversible punctate epithelial erosions of the cornea were observed in the two treatment groups and were attributed to the anesthetic effect and the aesthesiometry procedure.

CONCLUSIONS

In the current study, the 2% lidocaine gel provided a sustained, deep and well-tolerated corneal anesthesia in ophthalmically normal dogs.

Subconjunctival nodule due to Setaria equina erratic migration in a horse: First case report

An 18-month-old Arabian-English filly resident in southwest France was referred for evaluation of a conjunctival mass in the right eye (OD). A pink, solid, and mobile nodular formation, measuring approximately 1.2 × 0.8 cm was found under the superior nasal bulbar conjunctiva during an ophthalmic examination that was otherwise normal. The mass was surgically removed using a standing procedure. Cytological examination of fine-needle aspirates from the mass revealed a mixed eosinophilic-lymphocytic inflammation. Histological examination confirmed the dense and diffuse eosinophilic-lymphocytic infiltrate of the mass, and it revealed several cross sections of a parasitic nematode. The morphometric diagnosis identified an immature form of a filarial worm, and molecular analysis of the mitochondrial cytochrome c oxydase subunit 1 (cox1) and 12S rRNA gene sequences led to further identification of the specimen as Setaria equina. Microfilaremia was not observed on fresh blood smears. There have been no signs of local recurrence after 18 months, nor any evidence of intraocular involvement. To the authors' knowledge, this is the first documented case of subconjunctival setariasis due to S equina in a horse.

Congenital lacrimal fistula in two prim'Holstein calves

Two 4- and 8-month-old prim'Holstein calves were presented for chronic epiphora. Examination of the affected eyes revealed an abnormal duct opening inferonasal to the medial canthus. A diagnosis of congenital lacrimal fistula was made based on conventional and computed tomographic-dacryocystography findings. These revealed an ectopic channel connecting the nasolacrimal duct to the skin opening near the medial canthus. Both of the calves were surgically treated with resection and closure of the ectopic duct and placement of a nasolacrimal stent.

Submicroscopic deletions at 13q32.1 cause congenital microcoria

Congenital microcoria (MCOR) is a rare autosomal-dominant disorder characterized by inability of the iris to dilate owing to absence of dilator pupillae muscle. So far, a dozen MCOR-affected families have been reported worldwide. By using whole-genome oligonucleotide array CGH, we have identified deletions at 13q32.1 segregating with MCOR in six families originating from France, Japan, and Mexico. Breakpoint sequence analyses showed nonrecurrent deletions in 5/6 families. The deletions varied from 35 kbp to 80 kbp in size, but invariably encompassed or interrupted only two genes: TGDS encoding the TDP-glucose 4,6-dehydratase and GPR180 encoding the G protein-coupled receptor 180, also known as intimal thickness-related receptor (ITR). Unlike TGDS which has no known function in muscle cells, GPR180 is involved in the regulation of smooth muscle cell growth. The identification of a null GPR180 mutation segregating over two generations with iridocorneal angle dysgenesis, which can be regarded as a MCOR endophenotype, is consistent with the view that deletions of this gene, with or without the loss of elements regulating the expression of neighboring genes, are the cause of MCOR.

Degree and duration of corneal anesthesia after topical application of 0.4% oxybuprocaine hydrochloride ophthalmic solution in ophthalmically normal dogs

OBJECTIVE

To assess the anesthetic efficacy and local tolerance of topically applied 0.4% oxybuprocaine ophthalmic solution to in dogs and compare its effects with those of 1% tetracaine solution.

ANIMALS

34 ophthalmically normal Beagles.

PROCEDURES

Dogs were assigned to 2 groups, and baseline corneal touch threshold (CTT) was measured bilaterally with a Cochet-Bonnet aesthesiometer. Dogs of group 1 (n = 22) received a single drop of 0.4% oxybuprocaine ophthalmic solution in one eye and saline (0.9% NaCl) solution (control treatment) in the contralateral eye. Dogs of group 2 (n = 12) received a single drop of 0.4% oxybuprocaine ophthalmic solution in one eye and 1% tetracaine ophthalmic solution in the contralateral eye. The CTT of each eye was measured 1 and 5 minutes after topical application and then at 5-minute intervals until 75 minutes after topical application.

RESULTS

CTT changes over time differed significantly between oxybuprocaine-treated and control eyes. After instillation of oxybuprocaine, maximal corneal anesthesia (CTT = 0) was achieved within 1 minute, and CTT was significantly decreased from 1 to 45 minutes, compared with the baseline value. No significant difference in onset, depth, and duration of corneal anesthesia was found between oxybuprocaine-treated and tetracaine-treated eyes. Conjunctival hyperemia and chemosis were detected more frequently in tetracaine-treated eyes than in oxybuprocaine-treated eyes.

CONCLUSIONS AND CLINICAL RELEVANCE

Topical application of oxybuprocaine and tetracaine similarly reduced corneal sensitivity in dogs, but oxybuprocaine was less irritating to the conjunctiva than was tetracaine.

Florfenicol concentrations in ovine tear fluid following intramuscular and subcutaneous administration and comparison with the minimum inhibitory concentrations against mycoplasmal strains potentially involved in infectious keratoconjunctivitis

OBJECTIVE

To measure florfenicol concentrations in ovine tear fluid after IM and SC administration and determine minimum inhibitory concentrations (MICs) of florfenicol against field isolates of Mycoplasma organisms potentially involved in infectious keratoconjunctivitis.

ANIMALS

9 healthy adult Lacaune ewes.

PROCEDURES

Animals received an IM and SC administration of florfenicol (20 mg/kg) in a 2-way crossover design. Samples of blood and tear fluid were collected before and for 24 hours after administration. Concentrations of florfenicol in plasma and tear fluid were measured via high-performance liquid chromatography. The MIC of florfenicol for various Mycoplasma strains cultured from sheep and goats was determined via an agar dilution method.

RESULTS

Mean florfenicol concentration in tear fluid for the 24-hour period was significantly higher after IM administration (0.70 μg/mL) than after SC administration (0.22 μg/mL) and was maintained for a longer duration. The lacrimal fluid-to-plasma concentration ratio was not different between the 2 routes of administration, with mean values of 40.2% and 32.5% after IM and SC administration, respectively. The MIC for Mycoplasma agalactiae, Mycoplasma conjunctivae, and Mycoplasma mycoides isolates ranged from 0.5 to 8 μg of florfenicol/mL. Two strains of M agalactiae could be considered resistant to florfenicol.

CONCLUSIONS AND CLINICAL RELEVANCE

Florfenicol readily penetrated the preocular tear fluid of sheep after IM and SC administration. For both routes of administration, doses > 20 mg/kg would be necessary to achieve tear fluid concentrations of florfenicol greater than the MICs for most strains of Mycoplasma organisms.

Infectious sacroiliitis: a retrospective, multicentre study of 39 adults

Background

Non-brucellar and non-tuberculous infectious sacroiliitis (ISI) is a rare disease, with misleading clinical signs that delay diagnosis. Most observations are based on isolated case reports or small case series. Our aim was to describe the clinical, bacteriological, and radiological characteristics of ISI, as well as the evolution of these arthritis cases under treatment.

Methods

This retrospective study included all ISI cases diagnosed between 1995 and 2011 in eight French rheumatology departments. ISI was diagnosed if sacroiliitis was confirmed bacteriologically or, in the absence of pathogenic agents, if clinical, biological, and radiological data was compatible with this diagnosis and evolution was favourable under antibiotic therapy.

Results

Overall, 39 cases of ISI were identified in adults, comprising 23 women and 16 men, with a mean age at diagnosis of 39.7 ± 18.1 years. The left sacroiliac joint (SI) was affected in 59% of cases, with five cases occurring during the post-partum period. Lumbogluteal pain was the most common symptom (36/39). Manipulations of the SI joint were performed in seven patients and were always painful. Mean score for pain using the visual analogue score was 7.3/10 at admission, while 16 patients were febrile at diagnosis. No risk factor was found for 30.7% of patients. A diagnosis of ISI was only suspected in five cases at admission. The mean time to diagnosis was long, being 43.3 ± 69.1 days on average. Mean C-reactive protein was 149.7 ± 115.3 mg/l, and leukocytosis (leukocytes ≥ 10 G/l) was uncommon (n = 15) (mean level of leukocytes 10.4 ± 3.5 G/l). Radiographs (n = 33) were abnormal in 20 cases, revealing lesions of SI, while an abdominopelvic computed tomography (CT) scan (n = 27) was abnormal in 21 cases, suggesting arthritis of the SI joints in 13 cases (48.1%) and a psoas abscess in eight. Bone scans (n = 14) showed hyperfixation of the SI in 13 cases. Magnetic resonance imaging (MRI) (n = 27), when focused on the SI (n = 25), directed towards the diagnosis to ISI in 25 cases. Pathogenic agents were isolated in 33 cases (84.6%) by means of articular puncture (n = 16), blood culture (n = 14), cytobacteriological examination of urine (n = 2), or puncture of the psoas (n = 1).

Gram-positive cocci were the mostly isolated common bacteria, with a predominance of staphylococci (n = 21). The most frequently isolated gram-negative bacillus was Pseudomonas aeruginosa (n = 3). Evolution was favourable in 37 out of 39 patients under prolonged antibiotic therapy (mean duration 3.01 ± 1.21 months).

Conclusion

Our series confirmed that the clinical manifestations of ISI usually lead to delayed diagnosis. Based on our results, we suggest performing an MRI of the spine and SI in clinical situations characterised by lumbogluteal pain and symptoms of an infectious disease, such as fever.

Clinical, electroretinographic and histomorphometric evaluation of the retina in sheep with natural scrapie

Background

The retina is part of the diencephalon in a peripheral location and may be involved in prion diseases. Retinal function and structural changes were assessed in naturally scrapie-affected red face Manech ewes presenting the classical signs of the disease, and clinically healthy age-matched subjects for controls. Ophthalmic examination was done prior to electroretinography (ERG), which was carried out under conditions that allowed photopic and scotopic activities to be assessed. Histomorphometry of the inner and outer retinal layers was performed post-mortem, and retinas were also examined for evidence of abnormal prion protein (PrP^Sc) accumulation and glial fibrillary acidic protein (GFAP) upregulation as a marker of gliosis. Scrapie status was determined by examination of brain tissue

Results

Ocular reflexes and ophthalmoscopy did not reveal any difference between scrapie affected and control animals. Although the light-and dark-adapted ERG responses of both rod-and cone-mediated functions had a similar waveform in scrapie-affected and control sheep, a significant reduction in the amplitude of the ERG a-and b-waves was observed in affected animals compared to controls. These functional alterations were correlated with a substantial loss of cells in the outer nuclear layer (ONL), lengthening and disorganization in photoreceptor segments, and substantial reduction in cellularity and thickness of the inner nuclear layer (INL). The degenerative changes in the INL and ONL were most marked in the central and paracentral areas of the scrapie retinas, and were accompanied in all scrapie retinas by PrP^Sc deposition in the ganglion cell and synaptic layers. GFAP immunoreactivity was mainly increased in the ganglion cell and inner plexiform layers.

Conclusions

No appreciable fundoscopic changes were observed in the scrapie-affected ewes although reproducible changes in retinal function as measured by ERG were observed in these animals. The alterations in the receptoral and post-receptoral pathways corresponded to the degenerative lesions observed in the ONL and INL of the scrapie retinas. The retinal degeneration was associated with prion protein infectivity which presumably spread via the optic nerve.

Linkage disequilibrium between HLA-G*0104 and HLA-E*0103 alleles in Tswa Pygmies

Nonclassical human leukocyte antigen (HLA)-G and -E loci are separated by approximately 660 kb on the short arm of chromosome 6. Interestingly, some functional and expression characteristics are relatively identical or associated for both molecules. For example, expression of HLA-E on the cell surface has been linked to preferential binding of nonameric leader peptides derived from the signal sequence of HLA-G. It has been suggested that these two molecules act synergistically in modulating susceptibility to infectious or chronic inflammatory diseases. A possible explanation for these observations is that HLA-E and HLA-G are evolving under analogous selective pressures and have functions that place them under selective regimes differing from classical HLA genes. The purpose of this study was to investigate the consistency of this hypothesis based on the characterization of the molecular polymorphism of these two genes and their linkage disequilibrium (LD) in three populations, i.e. Southeastern French (n = 57), Teke Congolese (n = 84) and Tswa Pygmies (n = 74). Allelic frequencies observed for HLA-G and HLA-E and for 14-bp ins/del polymorphism in the three populations were similar to those observed in the literature for populations from corresponding geographic areas. Only one of the recently described HLA-G polymorphisms (HLA-G*01:07-01:16) was found, i.e. HLA-G*01:15 in one individual from Congo. We showed that two haplotypes in Tswa Pygmies, i.e. HLA-G*01:04-E*01:03:01 and G*01:04-E*01:01, exhibited highly significant positive and negative D' values respectively. Although these LD could have functional implications, it is more likely because of the genetic drift as the two other populations did not display any significant LD.

Intraocular pharmacokinetics of intravenously administered marbofloxacin in rabbits with experimentally induced acute endophthalmitis

OBJECTIVE

To compare penetration of IV administered marbofloxacin in intraocular fluids of healthy and inflamed eyes in rabbits with endotoxin-induced endophthalmitis.

ANIMALS

35 pigmented rabbits.

PROCEDURES

Endophthalmitis was induced in the right eye via intravitreal administration of Escherichia coli endotoxin. The left eye was a control eye. After 24 hours, a single dose of marbofloxacin (4 mg/kg, IV) was administered. Groups of rabbits (n = 5/group) were euthanized 0.5, 1, 2, 4, 6, 10, and 18 hours later, and blood and ocular fluids were collected. Marbofloxacin concentrations were determined via reverse-phase high-performance liquid chromatography, and pharmacokinetic analysis of the data was performed with a mono-compartmental model.

RESULTS

Mean area under the aqueous concentration-time curve was significantly lower in control eyes (1.64 +/- 0.07 microg*h/mL) than in inflamed eyes (3.31 +/- 0.11 microg*h/mL). Similarly, drug penetration into aqueous humor was 33% and 65% for control eyes and inflamed eyes, respectively. Mean area under the vitreous humor concentration-time curve for control eyes(1.75 +/- 0.05 microg*h/mL) was significantly less than for inflamed eyes (2.39 +/- 0.16 microg*h/mL). In the vitreous humor, corresponding penetrations were 34% and 47%, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Penetration of marbofloxacin into the aqueous and vitreous humor after IV administration was significantly enhanced by intraocular inflammation, suggesting a role for this antimicrobial in the prophylaxis or treatment of bacterial endophthalmitis caused by susceptible pathogens.

Congenital orbital cysts of neural tissue in two dogs

A 3-month-old English Cocker Spaniel and a 6-month-old miniature poodle presented with clinical signs related to an abnormal right eye since birth. In both dogs, the right globe could not be identified and was replaced by a fluctuant intraorbital mass covered by a vascularized mucous membrane. Ultrasonography demonstrated that both masses were cystic structures markedly larger in size than the normal contralateral globes. In both cases, surgical excision revealed a multilobular cyst filling the whole orbital cavity. Histopathologic examination and immunostaining for glial fibrillary acid protein and S100 protein supported a diagnosis of neural cysts associated with ocular dysplasia. The definitive diagnosis was congenital cystic eye and microphthalmos with cyst for the Cocker Spaniel and miniature poodle, respectively. Karyotype was normal in both dogs. Congenital cystic eye and microphthalmos with cyst result from defects in early embryonic life that arise following formation of the optic vesicle and prior to closure of the optic fissure. To the authors' knowledge neither has been reported in the canine species. They should be considered in the differential diagnosis of orbital cysts in dogs.

Comparison of cytologic and histologic evaluations of the conjunctiva in the normal equine eye

OBJECTIVE

To describe the cells observed in conjunctival brush cytology (CBC) from normal horses and compare these findings with conjunctival structural histology so as to understand which cells are recovered from CBC.

METHODS

This study was divided into three parts. (1) Conjunctival brush smears were collected from 20 healthy horses on both eyes and a differential count on 300 cells was carried out on May Grünwald-Giemsa (MGG) smears. (2) A similar protocol was used for whole eyes from five horses obtained rapidly after death from a slaughterhouse. The eyes were then assessed for conjunctival histology. (3) Cytobrush smears were collected from five healthy horses. Smears were examined after MGG or periodic acid Schiff (PAS) staining.

RESULTS

The differential cell count showed a majority of deep and intermediate epithelial cells with very few superficial and goblet cells in both eyes. A stratified columnar to cuboidal epithelium was observed on nearly the whole surface of the conjunctiva. A stratified squamous type was observed at the palpebral and bulbar edges. Areas with highest mucus cell indices were found from the nasal to the temporal edge of the equine inferior conjunctiva in the upper palpebral segment near the fornix and in a part of the nasal fornix. In MGG smears no mucus cells were identified; however, they were numerous in PAS smears (22.6% +/- 11) and were mostly cylindrical cells (42.5% +/- 14.4 PAS positive).

CONCLUSIONS

Cytobrush smears in the healthy horse are characterized by a majority of polyhedral and cylindrical cells and a few squamous cells. The cylindrical cells may be mucous cells and probably originate from the main stratified columnar to cuboidal epithelium.

Ocular effects of topical 0.03% bimatoprost solution in normotensive feline eyes

OBJECTIVE

The current study was undertaken to evaluate the effects of topically applied bimatoprost, an ocular hypotensive lipid, on intraocular pressure (IOP) and pupil size (PS) in healthy cats.

ANIMAL STUDIED

Nine European Shorthair cats free from clinically relevant ocular abnormalities were used in the study.

PROCEDURES

Pretreatment baseline measurements of IOP and PS were obtained bilaterally at 8 am, 2 pm, and 8 pm for five consecutive days (days 1 to 5). Then the cats received one drop twice daily (10 am and 6 pm) of bimatoprost ophthalmic solution 0.03% (Lumigantrade mark, Allergan Inc., Irvine, CA USA), in one randomly selected eye and one drop of artificial tears in the fellow eye (control eye) for 5 days (days 6 to 10). Values for IOP and PS were obtained under the same conditions as in the pretreatment phase. The potential for ocular irritation following bimatoprost application was also evaluated.

RESULTS

During the pretreatment period, the mean IOP and mean PS were not significantly different between the eyes subsequently treated with bimatoprost and those subsequently determined as controls. During the treatment period, the mean IOP in bimatoprost-treated eyes was not significantly lower than in control eyes (14.2+/-2.3 vs. 14.5+/-2.8 mmHg). Mean IOP in control eyes was not significantly changed at any time during the study period. A marked reduction of PS was seen in all bimatoprost-treated eyes, but no other clinically relevant side effects were observed.

CONCLUSION

Twice daily topical applications of bimatoprost produced miosis but had no significant effect on IOP in healthy cats.

Topical treatment of non-healing corneal epithelial ulcers in dogs with aminocaproic acid

The potential efficacy of topical epsilon-aminocaproic acid, an antiplasmin agent, in the treatment of persistent corneal epithelial defects was evaluated in a study of the medical records of 44 dogs, in which 51 eyes had been diagnosed with a corneal epithelial defect lasting more than 10 days, with no apparent underlying cause. At an initial examination all the affected eyes had had non-adherent epithelium removed. Thirty-four of the eyes in 28 dogs examined between January 2000 and March 2003 were also treated by the topical application of a solution of 35.7 mg/ml ophthalmic aminocaproic acid three times a day; the other 17 eyes in 16 dogs treated between October 1997 and March 1999 had received only topical treatment with gentamicin in addition to the debridement. Both groups were assessed clinically at weekly intervals for a maximum of three weeks. The two groups had approximately the same breed distribution, and there were no statistically significant differences between them in terms of their age, sex, affected side or duration of the corneal erosions. After three weeks, 32 of the 34 eyes treated with aminocaproic acid (94.1 per cent) had been cured, compared with seven of the 17 eyes treated with gentamicin (41.2 per cent) (P=0.0001). No adverse drug reactions were reported.

Multiple eyelid apocrine hidrocystomas in two Persian cats

Abstract Two middle-aged Persian cats were presented for evaluation of periocular masses. On examination, multiple pigmented nodules, 2-10 mm in diameter, were found in the periocular skin. Excisional biopsy revealed unilocular cystic lesions derived from apocrine sweat glands and resembling apocrine hidrocystomas of the eyelids described in humans. Immunostaining for Ki67 identified actively proliferating epithelial cells and demonstrated, for the first time, that these cystic lesions are adenomatous proliferative tumors (cystadenomas) rather than retention cysts. In both cases, additional lesions appeared within 6 to 9 months at affected and previously unaffected sites on the eyelids.

Population pharmacokinetics of marbofloxacin in aqueous humor after intravenous administration in dogs

OBJECTIVE

To evaluate, by use of population pharmacokinetics, the disposition of marbofloxacin in the aqueous humor after IV administration in dogs and identify its potential usefulness in the prophylaxis and treatment of intraocular infection.

ANIMALS

63 dogs.

METHODS

Dogs received a single dose of marbofloxacin (2 mg x kg(-1), IV) at various time intervals before cataract surgery. Aqueous humor and blood samples were collected at the beginning of surgery. Marbofloxacin concentrations were measured by high-pressure liquid chromatography. Data were analyzed with a nonlinear mixed-effect model and, by use of population pharmacokinetic parameters, the time course of aqueous humor concentration was simulated for single doses of 3, 4, and 5.5 mg x kg(-1) IV. Pharmacodynamic surrogate markers and measured aqueous humor concentrations were used to predict in vivo antimicrobial activity.

RESULTS

A maximum marbofloxacin concentration of 0.41 +/- 0.17 microg x mL(-1) was reached in the aqueous humor 3.5 hours after IV administration. In the post-distributive phase, marbofloxacin disappeared from aqueous humor with a half-life of 780 minutes. The percentage penetration into the aqueous humor was 38%. Predictors of antimicrobial effects of marbofloxacin (2 mg x kg(-1), IV) indicated that growth of the enterobacteriaceae and certain staphylococcal species would be inhibited in the aqueous humor. Marbofloxacin administered IV at a dose of 5.5 mg x kg(-1) would be predicted to inhibit growth of Pseudomonas aeruginosa and all strains of staphylococci but would not eradicate streptococcal infections.

CONCLUSIONS AND CLINICAL RELEVANCE

Marbofloxacin administered IV can penetrate the aqueous humor of canine eyes and may be suitable for prophylaxis or treatment of certain anterior chamber infections.

Tolerance of the rabbit cornea to an n-butyl-ester cyanoacrylate adhesive (Vetbond)

OBJECTIVE

An n-butyl-ester cyanoacrylate adhesive available for veterinary surgery (Vetbond, 3M) was tested in rabbits for corneal irritation.

PROCEDURES

Two experimental procedures were used on 24 rabbits: injection of the adhesive into an intralamellar corneal pocket (n = 10) and application of the glue to a mid-stromal corneal defect (n = 14). In both experiments the eyes were examined for 20 days for evidence of corneal irritation and tolerance. At the end of each experiment, histopathologic studies were performed on all corneas.

RESULTS

The corneal reaction to the intrastromally injected cyanoacrylate was characterized clinically by slight edema and vascularization localized to the vicinity of the adhesive. A moderate foreign body-type reaction was found histologically. Following application of the adhesive to a central stromal defect, the treated corneas remained totally clear and histopathologic examination showed that the healing process was not altered compared to the controls. The mean retention time of the glue patch was 14 days.

CONCLUSIONS

Intrastromal injection and surface application to a corneal defect of n-butyl-ester cyanoacrylate to a corneal defect induced only a mild inflammatory response and did not interfere with the reparative process. These findings suggest that this surgical adhesive would be acceptable for treating corneal ulcerations in animals.

Rifampicin and isoniazid increase acetaminophen and isoniazid cytotoxicity in human HepG2 hepatoma cells

Acetaminophen (APAP) induced a concentration-dependent (0-30 mM) cytotoxic effect in human HepG2 hepatoma cells which was significantly increased when intracellular reduced glutathione (GSH) content was decreased. The cytotoxic effect of APAP (0-30 mM) was significantly lower in a day 3-treated compared to day 1-treated HepG2 cells. A 3-day preincubation of HepG2 cells with 5 microM 3-methylcholanthrene (3MC), 50 microM rifampicin (RFP) or 1 mM isoniazid (INH) significantly increased 15-30 mM APAP cytotoxicity, of about 15-20% for INH and RFP and 35-50% for 3MC. The cytotoxicity of 10 mM APAP was also increased (about 20%) by a 3-day preincubation with INH but was not affected by 3MC and RFP. INH induced a concentration-dependent (0-40 mM) cytotoxic effect in day-1 treated HepG2 cells and not significantly affected by decreases in intracellular GSH concentrations. INH was not cytotoxic in day 3-treated HepG2 cells. A 3-day preincubation of HepG2 cells with 50 mM RFP or 1 mM INH significantly increased 10-40 mM INH cytotoxicity, respectively of about 10% and 10-25%. A 3-day preincubation with 3MC did not modify the cytotoxic effect of INH at these concentrations. This is to our knowledge the first report of increases by INH and RFP of APAP of INH cytotoxicity in vitro in hepatocellular cells of human origin. It is in accordance with clinical observations of severe hepatotoxicity associated with APAP or INH usage in patients receiving multiple drug therapy (INH, RFP) for tuberculosis or in alcoholics.

Growth hormone responses to growth hormone-releasing hormone and clonidine in dogs with Cushing's syndrome

The effects of clonidine, a growth hormone (GH) secretagogue, acting at the hypothalamic level and synthetic GH-releasing hormone (GHRH), a physiological stimulus of somatotrophs, on GH secretion were measured in 11 dogs with Cushing's syndrome. Eight healthy dogs served as controls. After the administration of GHRH the dogs with hyperadrenocorticism had a mean (SEM) GH peak of 11.2 (2.5) ng ml-1 which was significantly lower than the peak of 48.6 (13.4) ng ml-1 observed in the healthy dogs. Similarly, the GH response to clonidine was inhibited in the dogs with hyperadrenocorticism, the mean GH peak being 9.3 (3.3) ng ml-1 compared with 135.6 (43.3) ng ml-1 in the control dogs. No significant difference between the GH responses to GHRH and clonidine was observed in the dogs with Cushing's syndrome, the areas under the response curves being 567.9 (78.2) and 478.0 (102.6) ng.min ml-1, respectively. These results demonstrate that the function of somatotrophs is abnormal in dogs with Cushing's syndrome. There is evidence that the likely action of clonidine in dogs is to inhibit the release of somatostatin and the results therefore suggest that the effect of an excess of glucocorticoid in the dog is probably not mediated through an increase in somatostatin tone.

Effect of propranolol on growth hormone response to GH releasing hormone (GHRH 1-44) in the dog

The present study was undertaken to examine whether beta-adrenergic blockade with propranolol might influence and make less variable the growth hormone (GH) response to exogenous GH releasing hormone (GHRH) 1-44 in the dog. On four separate occasions eight healthy beagles, one to two years old, randomly received either propranolol (40 micrograms kg-1 intravenously) or an equivalent volume of saline, 30 minutes before either GHRH 1-44 (1 microgram kg-1 intravenously) or vehicle was injected. After propranolol alone, GH secretion did not differ from saline (area under the curve [AUC]: 649.5 +/- 128.3 v 633.2 +/- 87.7 ng min ml-1, respectively). GHRH alone elicited a significant increase in GH secretion (AUC: 1230.5 +/- 210.5 ng min ml-1) with a peak concentration of 16.7 +/- 4.8 ng ml-1. When GHRH was injected after propranolol the mean peak (59.1 +/- 14.7 ng ml-1) and secretory area (AUC: 2631.0 +/- 474.4 ng min ml-1) were greater than those observed after GHRH alone. However, from a clinical point of view propranolol pretreatment does not modify the great individual variability of the GH response to GHRH.

Growth hormone response induced by synthetic human growth hormone-releasing factor (1-44) in healthy dogs

The growth hormone (GH) secretory response to varying doses (1, 5 and 25 micrograms/kg) of intravenous (i.v.) human GH releasing factor (GRF) (1-44) was measured in four, 16-month-old female dogs and compared to the GH response to placebo (vehicle solubilizing GRF) and standard clonidine test (10 micrograms/kg i.v.). The three doses of GRF had no apparent clinical side effects and were capable of eliciting a rapid increase in the mean plasma GH level. The rise in plasma GH occurred within 5 minutes with a peak response at 15-30 minutes. However inter-subject variability of the GH response was large in terms of magnitude and time course. By analysis of the areas under the response curves it was shown that GRF 1-44 was as effective in stimulating GH release as clonidine and that a dose of 1 microgram/kg GRF 1-44 could be a good choice for use as a standard test dose in the dog.

An unusual dermal collagen disorder in a dog

An adult dog developed a connective tissue disorder characterized by hyperextensibility of the skin on the head, neck and shoulders. Under light microscopy, the thickness of the dermis was reduced and the collagen bundles were fragmented. Hypodermic lesions appeared as fat necrosis and swelling of the wall of the blood vessels. Electron microscopically, the packing of collagen bundles and fibres in the dermis was highly disorganized and the rough endoplasmic reticulum of fibroblasts showed dilatation of the cisternae. Whereas the dermal lesions were non-specific, this case differed fundamentally from canine inherited collagen diseases in that the clinical features appeared in an old dog and the dermal lesions were only localized and were associated with hypodermal atrophy.

Effect of flunixin meglumine on the breakdown of the blood-aqueous barrier following paracentesis in the canine eye

The protein and PGE2 metabolite content of the aqueous humor from untreated and flunixin meglumine pretreated dogs was determined prior to and after anterior chamber paracentesis. In the untreated dogs the concentrations of protein and PGE2 metabolite in aqueous humor were greatly elevated secondary to paracentesis. Intravenously administered flunixin meglumine (1.1 mg/kg or 2.2 mg/kg) significantly reduced these inflammatory parameters, confirming that prostaglandins are involved in the stability of the blood-aqueous barrier by paracentesis in the canine eye. The clinical implication of these results is that intravenous administration of flunixin meglumine before intraocular surgery should be considered as an adjunct therapy to reduce intraoperative and postoperative uveitis.

Effect of lysine-acetylsalicylate and phenylbutazone premedication on the protein content of secondary aqueous humour in the dog

Inhibitory effects of the anti-inflammatory agents lysine-acetylsalicylate (LAS) and phenylbutazone (PBZ) on the breakdown of the blood-aqueous barrier by paracentesis were studied in canine eyes using protein determination of ocular fluid. In the untreated eyes the aqueous protein value was raised from 0.29 +/- 0.17 (mean +/- SD) g litre-1 at the initial paracentesis to 14.47 +/- 4.10 g litre-1 at the second paracentesis. Pretreatment with LAS or PBZ had no significant effect on the protein concentration of the primary aqueous humour. However the secondary aqueous protein concentration was only 10.05 +/- 7.00 g litre-1 with LAS and 5.80 +/- 3.83 g litre-1 with PBZ. With both drugs the maximum inhibitory effect was observed on the gammaglobulins and albumin. These results suggest that prostaglandins may be involved in the response of the canine eye to paracentesis and that premedication with LAS or PBZ may be of value in reducing postoperative ocular inflammation.

Adrenocortical function and plasma biochemical values in dogs after subconjunctival treatment with methylprednisolone acetate

The effects of subconjunctivally administered methylprednisolone acetate on adrenocortical function and blood composition were studied in five dogs. Two 10 mg doses of methylprednisolone acetate were injected at an interval of 21 days. Plasma cortisol concentrations (COR), ACTH-stimulated cortisol concentrations and other blood components were determined regularly. The normal plasma COR (5.7 +/- 2.62 ng/ml) was one of the lowest reported in the literature for the dog, possibly because of the specificity of the high performance liquid chromatographic assay and the experimental environment. Plasma COR was depressed only after the first administration of methylprednisolone acetate. ACTH stimulated COR was significantly depressed nine and 20 days after the first and second subconjunctival injection respectively. Otherwise blood composition was unchanged.

[Pseudo-tumoral human African trypanosomiasis due to Trypanosoma gambiense. Clinical and tomodensitometry study (author's transl)]

The authors report an observation of african trypanosomiasis due to Trypanosoma Gambiense, clinical signs included massive and progressive hemiplegia, papillary edema and vascular shift from median line at arteriography. These pseudo tumoral clinical features are unusual in this disease. Asymetrical heterogenous hypodensities of the centrum semioval are dominant in the initial CT scanner aspect. The confrontation of CT scanner images to the clinical and evolutive data suggests the presence of associated cerebral edema and demyelination. With treatment, hypodensities were regressing while images of subcortical atrophy appeared. Lastly, in spite of severe general signs and the importance of neurological deficit, arsenical treatment associated with high doses of corticotherapy lead to a rapid improvement.