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Biomedical subjects

T J Kern

Publications and source records attributed to T J Kern.

15 recordsLinked to original sources
PubMed1992

Refractive state, corneal curvature, accommodative range and ocular anatomy of the Asian elephant (Elephas maximus).

The resting refractive state of six mature, female, Asian elephants (Elephas maximus) was determined using streak retinoscopy and neutralizing video retinoscopy. The amplitude of accommodation was also measured by neutralizing video retinoscopy of two animals and the corneal curvatures of three animals was measured by photokeratoscopy. The net spherical refraction was found to be +0.23 D. No difference was observed between cyclopleged and non-cyclopleged eyes (data from three animals), nor was there any difference between right and left eyes. Nine of the twelve eyes refracted had > or = 0.5 D astigmatism. The mean corneal power, as measured by photokeratometry was 21.3 D (SD = 1.8 D). There was a tendency towards with-the-rule corneal astigmatism in our sample (mean value: 1.2 D), though it did not reach statistical significance (P = 0.06). Two elephants were examined using neutralizing video photoretinoscopy. They were able to accommodate through 3 D. Three fixed eyes from three different elephants were obtained for gross and microscopic examination. The mean axial length of the eye was 38.75 mm and the lens had an axial diameter of approx. 10 mm. The posterior sclera was thick (8.0-8.5 mm). Histologically, the cornea was comprised of five distinct layers. A thin, meridionally oriented smooth ciliary muscle was identified. Individual muscle fibers were also observed associated with the posterior trabeculae of the uveal meshwork.

Accommodation, Ocular↗
PubMed1990

Ulcerative keratitis.

Ulcerative keratitis comprises an important proportion of presenting ocular complaints in small animals. Because of its high frequency, corneal ulceration may not routinely stimulate the clinical concern for rigorous diagnosis, attentive management, and aversion of potential complications that it merits. Only by maintaining an appreciation for the pathologic processes at work during corneal injury and repair can busy clinicians competently diagnose, successfully treat, and forestall the complications of corneal ulceration.

Animals↗
PubMed1989

Horner's syndrome in dogs and cats: 100 cases (1975-1985).

The medical records of 74 dogs and 26 cats with Horner's syndrome (HS) that were admitted to the New York State College of Veterinary Medicine between January 1975 and October 1985 were reviewed. In dogs, but not cats, HS was associated significantly (P less than 0.01) with increasing age. Dogs with hypothyroidism (defined liberally but not rigorously), intracranial neoplasia, or thoracic neoplasia, cats with otitis media/interna (defined liberally), and dogs and cats with brachial plexus root avulsion were at greater risk for developing HS than were animals that were hit by a car. Dogs and cats with otitis externa were at less risk of developing HS than were animals that were hit by a car. The cause of HS could not be determined in 50% of dogs and 42.3% of cats. The results of topical adrenergic drug testing in dogs were inconclusive in localizing lesion site. In dogs and cats, HS appeared to be unassociated with gender, breed, or right vs left side. The important causes of HS in dogs and cats were trauma (hit by car), brachial plexus root avulsion, intracranial and thoracic neoplasia, and otitis media/interna.

Animals↗
PubMed1988

Scanning electron microscopy of experimental keratoconjunctivitis sicca in dogs: cornea and bulbar conjunctiva.

Keratoconjunctivitis sicca was produced experimentally in 16 beagles by bilateral surgical removal of the lacrimal and nictitans glands; four dogs were not treated, and 12 received tear-replacement therapy on post-operative days 7 through 28. Keratoconjunctivitis sicca was verified by reduction in Schirmer tear test values by post-operative day 6, and there was no response on day 28 to tear-replacement therapy. Corneas of both normal and tear-deficient dogs had polygonal squamous epithelial cells of light and dark electron density by scanning electron microscopy. Light cells had more microvilli and microplicae than dark cells. Conjunctivae were similar to corneas, except for numerous goblet cells on the surface. Corneal dark-cell density and goblet cell density were not different between groups. Goblet cells most often occurred singly in normal dogs, while they were in clusters in tear-deficient dogs. A hypothesis that petrolatum/mineral oil ointment should provide more effective artificial tear replacement than hydroxymethylcellulose drops for tear-deficient dogs could not be confirmed by objective analysis of corneal dark-cell density or conjunctival goblet cell density.

Animals↗
PubMed1987

Facial neuropathy in dogs and cats: 95 cases (1975-1985).

The medical records of 79 dogs and 16 cats admitted to the New York State College of Veterinary Medicine between January 1975 and October 1985 with facial nerve dysfunction were reviewed. In 31 dogs and 8 cats, facial neuropathy was the only abnormal finding. In 48 dogs and 8 cats, the clinical findings most often noted in the records in addition to facial neuropathy were vestibular signs. Facial neuropathy appeared unassociated with gender or right vs left sides in both dogs and cats, or with hypothyroidism in dogs. Facial neuropathy was associated with increased age, with certain breeds in both dogs and cats, and with otitis media/interna and keratoconjunctivitis sicca in dogs. Causes of facial nerve dysfunction in dogs and cats included surgical and nonsurgical trauma, neoplasia, and otitis media/interna. Facial neuropathy was judged to be idiopathic in 74.7% of dogs and 25% of cats.

Animals↗
PubMed1985

Uveitis associated with poliosis and vitiligo in six dogs.

Idiopathic panuveitis with retinal detachment was associated with facial poliosis, vitiligo, and alopecia in 6 dogs; 4 were adult males. Dermatohistologic examination of affected facial sites from all dogs revealed a lichenoid dermatitis and unusual histiocytic cells. Intensive topical and systemic corticosteroid and topical mydriatic/cycloplegic therapy was successful in controlling uveitis in all dogs for variable periods. Three dogs, monitored for 12, 30, and 46 months, retained useful vision despite infrequent recurrence of uveitis. One dog was lost for subsequent examination. Two dogs were euthanatized and necropsied. Ocular histologic examination of these dogs revealed extensive granulomatous iridocyclitis and choroiditis, with retinal detachment and lenticular degeneration.

Adrenal Cortex Hormones↗
PubMed1985

Orbital neoplasia in 23 dogs.

Medical records of 23 dogs with histologically documented orbital neoplasia and admitted to the New York State College of Veterinary Medicine between 1975 and 1984 were reviewed. Almost all (91%) of the tumors were classified as malignant; 74% of the tumors arose as primary neoplasms within the orbit. Eleven tumor types of connective tissue, bone, epithelial, and hemolymphatic origin were represented. The typically afflicted dog was purebred, female, and middle-aged. Review of this series confirmed the clinical impression that orbital neoplasms in dogs are aggressive malignancies with poor long-term prognosis.

Animals↗
PubMed1985

Multiple congenital ocular defects in the Akita dog.

Microphthalmia, congenital cataracts, posterior lenticonus, and retinal dysplasia were observed in members of 3 litters of Akita puppies thought to be related to a common male ancestor. The electroretinograms of 3 clinically affected puppies were normal. Histological examination of 6 microphthalmic animals revealed nuclear and cortical cataract with multiple retinal folds and rosettes predominantly overlying the tapetum lucidum. Posterior lenticonus was observed histologically in 3 of the 6 puppies.

Animals↗
PubMed1983

Enucleation in birds of prey.

Enucleation in birds requires special consideration. Two case reports are presented as examples of 2 techniques for enucleation in raptors. The first technique utilizes a transaural approach and is suitable only in owls that have extensive external ear openings. The major advantage of this technique is that it allows complete histologic examination of the globe. The second technique is a globe-collapsing procedure that is suitable for any avian species. This technique precludes complete histologic examination.

Animal Population Groups↗
PubMed1981

Habronemic blepharoconjunctivitis in horses.

Habronemic blepharoconjunctivitis was characterized clinically by raised yellow gritty plaques in the palpebral and bulbar conjunctivae. Lid granulomas and blepharitis were observed in some cases. On histologic examination, mast cells, eosinophils, and collagenolysis was found in most sections, but if only one section was examined an erroneous diagnosis of mastocytosis could have been made. Treatment consisted of larvicidal mixtures for lid lesions and organophosphate ophthalmic drops along with corticosteroids for the conjunctivitis. If the cornea was damaged by the gritty conjunctival plaques, healing was more prolonged because corticosteroids were then contraindicated.

Animals↗