Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Herbert E. Whiteley x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Summary

An experimental model of keratoconjunctivitis sicca (kcs) was produced by removing the lacrimal gland and the gland of the third eyelid from the left eye of 6 cats. The right eye of each cat was left intact and used as a control. After 2 weeks, cats were euthanatized and the central portion of the upper eyelid from both eyes of each cat was excised. Histologic sections were stained with either hematoxylin and eosin or with a battery of biotinylated lectins including concanavalin A (cona), soybean agglutinin (sba), wheat germ agglutinin (wga), succinylated wheat germ agglutinin (s-wga), Ulex europaeus agglutinin I (uea), Dolichos biflorus agglutinin (dba), Ricinus communis agglutinin (rca), peanut agglutinin (pna), and pna pretreated with neuraminidase.

Consistent differences in histologic features were not observed between conjunctivas with kcs and control conjunctivas. A variable degree of mononuclear cell infiltration of the substantia propria was observed in control conjunctivas and those with kcs. In both groups, conjunctival goblet cell density decreased and epithelial stratification increased as the degree of submucosal inflammatory cell infiltration increased.

Lectin binding sites for dba, wga, s-wga, uea, pna, and pna pretreated with neuraminidase were detected on conjunctival goblet cells of conjunctivas with kcs and control conjunctivas. The mucus/glycocalyx layer of conjunctival epithelial cells in both groups of conjunctivas bound lectins rca, wga, uea, and cona, but inconsistently bound s-wga. In both groups, dba principally bound to the mucus layer overlying normal epithelium, whereas pna pretreated with neuraminidase consistently bound to the mucus layer of stratified epithelial surfaces free of goblet cells. Binding of sba to goblet cells and the mucus/glycocalyx layer was variable.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the electrodiagnostic and histologic response of short-term increases of intraocular pressure (IOP) on transient pattern electroretinograms (PERG) and flash electroretinograms (FERG) in the eyes of dogs.

Animals—8 healthy mixed-breed dogs.

Procedure—Transient PERG and FERG waveforms were recorded from dogs (while anesthetized) as IOP was increased from baseline (7 to 19 mm Hg) to 90 mm Hg. One hundred mean PERG responses and a single FERG response were recorded at each step during 3 recording sessions. Globes of each dog were enucleated after euthanasia on posttreatment day 7 and evaluated by a pathologist.

Results—Increases in spatial frequency resulted in decreased amplitudes of N2 (second negative PERG peak). Increases in IOP resulted in decreases in all 3 PERG waveforms and the FERG waveform. All values began to return to baseline after short-term increases in IOP on day 0, and waveforms were not significantly different on posttreatment days 3 and 7.

Conclusions—Data suggest that short-term increases in IOP affect PERG and FERG waveforms, and PERG waveforms are more sensitive to increases in IOP. Differences were not detected between treated and control eyes on histologic examination. Further studies are necessary to determine at what IOP permanent damage to ganglion and photoreceptor cells will develop and whether PERG is a reliable clinical diagnostic technique for use in dogs to reveal retinal damage that is secondary to increased IOP prior to changes in waveforms generated by FERG in dogs. (Am J Vet Res 2000;61:1087–1091)

Full access
in American Journal of Veterinary Research

Summary

Eighteen prolapses of the gland of the third eyelid in 17 Beagles were randomly allocated to 3 groups, which included nontreated (group 1, n = 6), excised (group 2, n = 4), and surgically repositioned (group 3, n = 8) glands. A Schirmer tear test (STT) was performed on affected and normal (control) eyes for 5 consecutive days on weeks 0 (baseline), 2, 4, 6, 8, 10, 12, 16, 18, 20, and 24. All prolapsed third eyelid glands were excised and examined histologically.

Ten female and 7 male Beagles were used in the prospective study. Mean age at prolapse was 35.1 weeks (range, 6 to 89 weeks). Control STT data revealed a population mean of 22.2 ± 2.1 mm/min. Complications developed in 4 of 6 eyes when the gland was allowed to remain in a prolapsed position. Complications for group-1 eyes were significantly (P < 0.005) greater than those for eyes in groups 2 and 3 (0 of 12). Comparison of affected and control eye baseline data revealed decreased STT values for eyes with prolapsed glands (P < 0.01). Mean differences between affected and control eyes were 2.2, 2.0, and 3.4 mm/min for groups 1, 2, and 3, respectively. A significant (P < 0.001) decrease in lacrimation (0.2 to 3.1 mm/min) in group-2 eyes was detected after removal of the gland. Tear production for affected eyes of nontreated dogs fluctuated above and below that of control eyes prior to excision of the prolapsed gland of the third eyelid; however, with time, affected and control eye STT values were not significantly different. Despite an increase in lacrimation after treatment of group-3 eyes, comparison of affected and control eye STT values revealed a persistent decrease in lacrimation (0 to 2.2 mm/min); however, reduction of lacrimation after surgical repositioning was less than that which resulted if the prolapsed gland of the third eyelid was excised (P < 0.02). Histologic changes in the gland of the third eyelid were mild, and significant differences were not detected among the 3 groups.

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

Fetal infectivity of Ehrlichia risticii was investigated in 19 ponies that were E risticii negative on the basis of results of an indirect fluorescent antibody (ifa) test. Thirteen pregnant ponies were infected by iv administration of E risticii between 90 and 180 days of gestation. Six pregnant ponies served as noninfected controls. Each infected pony had clinical signs of equine monocytic ehrlichiosis, was confirmed to be ehrlichemic, and developed an ifa titer to E risticii. Two infected ponies became recumbent, were unresponsive to supportive care, and were euthanatized. After recovery from clinical illness, the remaining ponies were observed throughout gestation for reproductive abnormalities. On abortion, each fetus was necropsied and tissue specimens from the liver, bone marrow, spleen, colon, and mesenteric lymph nodes were inoculated into canine monocyte cell cultures. Six infected ponies aborted at a mean 217 days of gestation, which was between postinoculation days 65 and 111. Five fetuses were recovered for evaluation, and E risticii was isolated from 4 of them. All 5 fetuses recovered had similar histologic findings, including enterocolitis, periportal hepatitis, and lymphoid hyperplasia with necrosis of the mesenteric lymph nodes and spleen. All 5 fetuses tested negative for IgG to E risticii, although 3 had low IgM titer to E risticii. The remaining 5 infected ponies had normal parturition. Presuckle ifa titer to E risticii was measured in 4 of the term foals, and results for 3 were positive. Two foals from infected ponies were monitored for 6 months and daily gain in body weight was comparable to that of a control foal. None of the control ponies became ill or seroconverted during the clinical illness phase, and none aborted throughout gestation. Two control ponies seroconverted to E risticii 6 weeks before parturition. Results of this study indicate that E risticii is a primary abortifacient under experimental conditions.

Free access
in American Journal of Veterinary Research