Normal anatomical and histochemical characteristics of the lacrimal glands in the American bison and cattle

Dorsal lacrimal glands, superior glands of the third eyelid and Harderian glands (deep gland of the third eyelid) from 19 bison and 18 cattle free of apparent ocular disease were examined to compare the normal anatomical properties of these glands. All glands were characterized and measured (length and width). The gross anatomy of the dorsal lacrimal glands was similar, with the exception of a bipartite gland in cattle. The bison's superior gland of the third eyelid and Harderian gland was longer as compared with cattle. A subset of the bison and cattle samples (five bison and five cattle) was sectioned for histological and histochemical analysis. The histology of the dorsal lacrimal and superior gland of the third eyelid revealed tubuloalveolar cells with basophilic vacuolated cytoplasm in bison and eosinophilic granular cytoplasm in cattle. The Harderian glands consisted of a tubuloalveolar anterior part combined with large lumens acini lined with cuboidal epithelium in the posterior part; the posterior part of the bison Harderian gland was more predominant than in cattle samples. Mucosubstance histochemistry revealed acidic and neutral glycoproteins with similar staining patterns in all glands of both species.

Effect of the blood substitute diaspirin crosslinked hemoglobin in rat mesenteric and human radial collateral arteries

The actions of the blood substitute diaspirin crosslinked hemoglobin (DCLHb) were investigated in rat (small mesenteric artery) and human (radial collateral artery) resistance vessels mounted in a wire myograph for isometric tension recording. DCLHb did not contract resting vessels from rats, but vasoconstrictor responses were observed in isolated arteries and perfused mesenteric beds prestimulated with threshold concentrations of methoxamine. The DCLHb contractile responses were greatly attenuated by N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or endothelial removal, whereas BQ-123 (endothelin A receptor antagonist), prazosin (alpha1-adrenoceptor antagonist), or indomethacin (cyclooxygenase inhibitor) had no effect. Endothelium-dependent relaxations to carbachol in both rat mesenteric and human radial collateral artery were inhibited by DCLHb. Relaxations to carbachol were studied in the presence of L-NAME or 25 mM KCl to investigate the effect of DCLHb on endothelium-derived hyperpolarizing factor (EDHF) and nitric oxide, respectively. In both rat and human vessels, EDHF-mediated relaxations were not affected by DCLHb preincubation, whereas the nitric oxide component of carbachol-induced relaxations was practically abolished. In conclusion, inhibition of the effects of basal nitric oxide release underpins the vasoconstrictor effects of DCLHb. DCLHb effectively abolishes the nitric oxide component of carbachol-induced relaxation, with no effect on the EDHF-mediated component in both isolated rat mesenteric and human radial collateral arteries.

Ophthalmic examination and conjunctival bacteriologic culture results from a herd of North American bison

OBJECTIVE

To establish ocular characteristics, determine nature and prevalence of ocular lesions, and identify representative bacterial flora from the conjunctiva of North American bison (Bison bison).

DESIGN

Prospective study.

ANIMALS

63 bison; 45 males and 18 females.

PROCEDURE

Ophthalmic examinations were performed on 1 group of 38 bison in December 1997 and on a second group of 25 in March 1998. Eyes were examined with a penlight, magnification loop, and indirect ophthalmoscope. Two culture swabs were used to obtain samples from the inferior conjunctival sac. One swab was submitted for isolation of bacteria and the second was submitted for isolation of Mycoplasma organisms.

RESULTS

15 ocular abnormalities were observed in 13 of the 63 bison. These included minor ocular discharge in 5 animals, 1 eyelid laceration, 1 periocular Demodex spp infection, 6 corneal abnormalities, 1 anterior synechia, and 1 cataract. Seventeen species of bacteria were isolated from the 63 swabs submitted for culture. The most prevalent bacteria were of the genus Bacillus (74.6%). Mycoplasma organisms were not observed.

CONCLUSIONS AND CLINICAL RELEVANCE

Corneal abnormalities were the most frequently identified ocular lesions in bison. Bacterial flora of the conjunctiva and ocular characteristics were similar to those reported for cattle.

Conjunctival microbial flora of clinically normal pigs

Conjunctival swab specimens from healthy pigs were cultured to determine normal microbial population. Four commercial swine operations were selected for study. Pigs of 4 age groups were tested: nursing pigs, nursery pigs, feeder pigs, and sows. Swab specimens were taken from the conjunctival sac of each pig. Bacterial, fungal, and mycoplasmal growth was determined separately. Chlamydia sp was detected by use of an ELISA. Bacteria were recovered from 98% of specimens evaluated. alpha-Streptococcus sp (89%) was the most commonly recovered organism, followed by Staphylococcus epidermidis (39%) and Staphylococcus sp (39%). Mycoplasma sp was not detected in any of the specimens. Chlamydia sp was identified in 28% of all specimens evaluated. These results are similar to reports of normal conjunctival flora in other domestic animals.

The effect of immunization route on rat serum and tear antibody responses to Chlamydia trachomatis

The effect of immunization route on the kinetics of serum and tear antibody responses to Chlamydia trachomatis was studied in a rat model. Rats received Chlamydia trachomatis serovar C/TW elementary bodies for two immunization cycles by ocular topical (OT) application or subconjunctival (SC) injection and in a second experiment for three immunization cycles by either OT application, gastrointestinal intubation (GI), or intraperitoneal injection (IP). Serum IgG and tear IgA antibodies to whole elementary bodies were measured sequentially following the secondary (2 degrees) and tertiary (3 degrees) immunization cycles. Serum IgG levels were minimal in the OT immunized group following 2 degrees and 3 degrees immunization. Serum IgG levels for the SC, GI, and IP immunized groups rose steadily following 2 degrees immunization reaching maximal levels between day (d)24 and d31. Levels of serum IgG antibodies were highest in the GI group following 3 degrees immunization. Tear IgA antibody responses were greatest in rats immunized by the OT route, the 2 degrees IgA response peaked by d9 and declined by d24. The 3 degrees OT tear IgA response peaked by d13 and was greater than the 2 degrees response. Tear IgA antibody levels in SC and GI immunized rats appeared by d3 following 2 degrees immunization but remained at low levels and were not noted until d20 in the GI group following 3 degrees immunization. Tear IgA antibody responses were not detectable in IP animals following 2 degrees or 3 degrees immunization. This study documents the immunogenicity of Chlamydia trachomatis serovar C/TW in the rat and shows that the OT route is most effective in eliciting IgA antibody responses in tears.

Determination of protein concentrations and their molecular weight in tears from cats with normal corneas and cats with corneal sequestrum

Protein concentration was determined, using the Bradford technique, in tears from cats with normal corneas and from cats with corneal sequestrum. Tears from the former group contained 5.81 +/- 2.29 mg of protein/ml; those from corneal sequestrum-affected cats contained 6.21 +/- 2.21 mg/ml. Difference between the 2 values was not significant. Molecular weight determination was made, using 4 to 20% sodium dodecyl sulfate-polyacrylamide gels. Molecular mass of proteins ranged from 263 to 14 kDa. There was no detectable difference in the band patterns for the 2 groups.

Anterior uveal melanoma, with secondary keratitis, cataract, and glaucoma, in a horse

Intraocular melanoma was diagnosed in a 13-year-old horse. Secondary clinical findings included keratitis, cataract, and glaucoma. The eye was enucleated. Follow-up information did not give an indication of metastatic disease.

Periorbital epidermoid cyst in the medial canthus of three dogs

Periorbital epidermoid cyst in the medial canthus was identified ultrasonographically and confirmed histologically in 3 dogs. Surgical resection of the cysts, with reconstruction of the lacrimal canaliculi, was curative in all 3 cases.