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SUMMARY

Cell proliferation kinetic values were established for the hair root matrix of primary anagen follicles of 14 Beagles and 4 Cocker Spaniels with healthy skin and 9 Cocker Spaniels with primary idiopathic seborrhea. Indices were established by intradermal pulse labeling with tritiated thymidine, followed by cutaneous biopsy and autoradiography. The hair root matrix cell labeling index was 23.4 ± 3.5% for Beagles, 24.4 ± 4.0% for healthy Cocker Spaniels, and 24.9 ± 4.3% for seborrheic Cocker Spaniels. These values indicate a rapidly proliferating cell population. Differences among these cell kinetic data for the 3 groups of dogs were not statistically significant. Although significant cell kinetic differences have been reported for other epidermal structures (interfollicular epithelium, upper hair follicle external root sheath, sebaceous glands) in seborrheic Cocker Spaniels, proliferation of hair root matrix cells apparently remains unaffected.

Free access
in American Journal of Veterinary Research

SUMMARY

Prophylactic efficacy of 4 antibacterial shampoos against Staphylococcus intermedins in dogs was determined by use of a controlled quantitative technique. Ten adult Beagles were used in the study. The antibacterial agents in the shampoos were 3.0% benzoyl peroxide, 0.5% Chlorhexidine acetate, 1.0% available iodine as a polyalkyle-neglycol-iodine complex, and a combination of 0.5% triclosan, 2.0% sulfur, and 2.0% salicylic acid. Treated and control sites were challenge exposed with 5.30 ± 0.10 (log10) S intermedins colony-forming units (cfu)/cm2 of skin and occluded for 5 hours. At the end of the test period, remaining bacteria were removed with a detergent cup-scrub technique and the total number of S intermedins cfu/cm2 skin was calculated for each treated and control site.

Nontreated bacteria-challenged control sites yielded 5.62 ± 0.65 S intermedins cfu/cm2 of skin. Staphylococcus intermedins recovery (cfu/cm2) from the treated sites was 0.94 ± 0.76 for benzoyl peroxide, 1.96 ± 1.33 for Chlorhexidine acetate, 3.11 ± 0.48 for organic iodine, and 4.69 ± 0.23 for triclosan-sulfur-salicylic acid. Each S intermedins recovery value from the 4 treated sites was significantly (P < 0.05) lower than that from the nontreated S intermedins challenge-exposed control site. Bacteria recovery values were also significantly (P < 0.05) different among the 4 shampoo-treated sites.

We concluded that all shampoos had significant (P < 0.05) prophylactic activity against S intermedins over 5 hours. The shampoo containing benzoyl peroxide was determined to have the greatest efficacy among the products tested.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To measure impedance audiometric values in clinically normal dogs that were sedated or anesthetized, evaluate effects of ear flushing on tympanometric measurements, and determine effects of performing acoustic reflex testing in a sound-attenuated room.

Animals—35 mixed-breed and purebred clientowned dogs and 21 laboratory-bred Beagles.

Procedures—Tympanometry and acoustic reflex testing were performed on 27 mixed-breed and purebred dogs under isoflurane anesthesia in a non–sound-attenuated room and 21 Beagles under sedation in a sound-attenuated room. Tympanometry was performed on 8 mixed-breed dogs under halothane anesthesia before and after ear canal flushing.

Results—Among impedance audiometric values, ear canal volume and compliance peak were smaller in Beagles than in mixed-breed dogs; differences among other values were not detected. Ear canal volume was dependent on body weight. Differences were not found for tympanometric values measured before and after ear canal flushing.

Conclusions and Clinical Relevance—Results of this study established reference range values for impedance audiometric measurements in clinically normal dogs under isoflurane anesthesia or sedation. Acoustic reflex testing does not need to be performed in a sound-attenuated room. The ear canals of clinically normal dogs can be flushed prior to performing tympanometry without altering the results. Impedance audiometry may be a useful noninvasive procedure for the diagnosis of otitis media in dogs. (Am J Vet Res 2000;61:442–445)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare reactivities to intradermal injection of extracts of Dermatophagoides farinae, Dermatophagoides pteronyssinus, house dust mite mix, and house dust in dogs suspected to have atopic dermatitis.

Design—Retrospective study.

Animals—115 dogs.

Procedures—Records of all dogs suspected to have atopic dermatitis that underwent intradermal testing between October 1996 and July 1998 were reviewed. Reactivities to intradermal injection of crude mixed house dust mite (1:25,000 wt/vol) and crude house dust (25 PNU/ml) extracts were compared with reactivities to intradermal injection of individual extracts of D farinae and D pteronyssinus (1:50,000 wt/vol).

Results—Ninety dogs were confirmed to have atopic dermatitis including 61 of the 69 dogs with positive reactions to either or both of the individual house dust mite extracts. Intradermal testing with the mixed house dust mite extract had sensitivity of 75%, specificity of 96%, and accuracy of 83%. Intradermal testing with the house dust extract had sensitivity of 30%, specificity of 93%, and accuracy of 56%.

Conclusions and Clinical Relevance—Results suggest that use of crude mixed house dust mite and crude house dust extracts for intradermal testing in dogs is not as accurate a method of determining house dust mite hypersensitivity as is the use of individual D farinae and D pteronyssinus extracts mainly because of the high percentage of false-negative results. Extracts of individual house dust mites are recommended for intradermal testing of dogs suspected to have atopic dermatitis. (J Am Vet Med Assoc 2000;217:536–540)

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the prevalence of late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with atopic dermatitis and an immediate reaction to D farinae.

Animals—6 healthy dogs and 20 dogs with atopic dermatitis and immediate reactions to D farinae.

Procedure—Intradermal tests were performed with D farinae at 1:1,000 wt/vol and 1:50,000 wt/vol concentrations, and skin reactivity was evaluated after 0.25, 6, and 24 hours. Serum D farinae-specific IgE antibodies were assayed. Extent of lesions (atopy index) and pruritus (visual analogue scale) were evaluated in dogs with atopic dermatitis.

Results—Late-phase reactions were observed in healthy dogs at 6 hours (n = 2 dogs) and 24 hours (1) with the 1:1,000 wt/vol concentration, and at 6 hours (1) and 24 hours (1) with the 1:50,000 wt/vol concentration of allergen. Late-phase reactions in healthy dogs were only observed in dogs with an immediate reaction to D farinae. Late-phase reactions were observed in 11 of 20 dogs with atopic dermatitis at 6 and 24 hours with the 1:1,000 wt/vol concentration and in 10 of 20 at 6 and 24 hours with the 1:50,000 wt/vol concentration of allergen. There was no difference in mean atopy index, mean visual analogue scale of pruritus, or mean serum D farinae-specific IgE concentration of dogs with a late-phase reaction, compared to dogs without a late-phase reaction.

Conclusion and Clinical Relevance—Late-phase reactions may be observed after an immediate reaction to intradermal skin testing in healthy and allergic dogs but are more commonly observed in dogs with atopic dermatitis. (Am J Vet Res 2002;63:69–73)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare clinical efficacy of pulse administration with itraconazole versus once daily administration for the treatment of cutaneous and otic M pachydermatis infection in dogs.

Design—Randomized controlled trial.

Animals—20 dogs.

Procedure—Dogs were treated with itraconazole orally (n = 10/group), using a pulse administration regimen (5 mg/kg [2.3 mg/lb], PO, q 24 h for 2 consecutive days per week for 3 weeks) or once daily administration (5 mg/kg, PO, q 24 h for 21 days). No other treatment was permitted. On days 0 and 21, clinical severity of cutaneous and otic disease was assessed, and samples were collected for cytologic examination and yeast culture. Cytology (sum of the mean number of yeast organisms per oil immersion field for affected sites) and culture (mean of the score for extent of yeast growth for samples from affected sites) scores were calculated.

Results—For dogs in both treatment groups, clinical severity of cutaneous and otic disease was significantly decreased by day 21, but decrease in severity was not significantly different between groups. Similarly, skin cytology, skin culture, and ear culture scores were significantly decreased on day 21, compared with day 0, for both groups, but decreases were not significantly different between groups except that dogs in the pulse administration group had a significantly greater decrease in ear culture scores than did dogs in the daily administration group. However, when cytology scores only for ear samples were analyzed, day 21 score was not significantly decreased, compared with day 0 score, for either group.

Conclusions and Clinical Relevance—Results suggested that both pulse administration and once daily administration of itraconazole were efficacious in the treatment of M pachydermatis cutaneous infection in dogs. However, adjunctive treatment may be needed in dogs with M pachydermatis otitis. (J Am Vet Med Assoc 2002;220:1807–1812)

Full access
in Journal of the American Veterinary Medical Association

Objective

To compare microbial flora and antimicrobial susceptibility patterns of isolated pathogens from the horizontal ear canal and middle ear in dogs with otitis media.

Design

Prospective study.

Animals

23 dogs with chronic bilateral otitis externa.

Procedures

Swab specimens of the horizontal ear canal and middle ear were obtained for cytologic analysis, bacterial culture, and antimicrobial susceptibility testing. Integrity of the tympanic membrane was observed. If the tympanic membrane was intact, myringotomy was performed to collect specimens.

Results

Otitis media was diagnosed in 38 of 46 (82.6%) ears evaluated. The tympanic membrane was intact in 71.1 % of the ears with otitis media. The 3 most common organisms isolated from the horizontal ear canal and middle ear were Staphylococcus intermedius, yeast, and Pseudomonas spp. A difference in total isolates or susceptibility patterns between the horizontal ear canal and middle ear was found in 34 (89.5%) ears. Compared with results of bacterial culture, cytologic examination of swab specimens was not as effective for detection of rods and cocci from the middle ear.

Clinical Implications

In dogs with chronic otitis externa, otitis media often exists even when there is an intact tympanic membrane. In our study, the same isolates were rarely found in the horizontal ear canal and middle ear. Therefore, to choose appropriate antimicrobial agents, in addition to cytologic examination, bacterial culture and susceptibility testing of swab specimens from the horizontal ear canal and middle ear should be performed. (J Am Vet Med Assoc 1998; 212:534-538)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare results of intradermal tests (IDT), conducted using environmental allergens, in horses without atopy and horses with chronic obstructive pulmonary disease (COPD).

Animals—38 horses (22 horses without atopy and 16 horses with COPD).

Procedure—All horses were examined (physical examination, hematologic examination, serum biochemical analyses, examination of bronchoalveolar lavage fluid). An IDT was conducted, using a full panel of 73 allergens consisting of grasses, weeds, trees, molds, and insects. Results of the IDT were evaluated 30 minutes and 4, 6, and 24 hours after injection of allergens. Horses without atopy were euthanatized, and gross and histologic changes of lung parenchyma were assessed.

Results—Horses without atopy had a greater number of positive immediate and late-phase reactions than did horses with COPD. Horses with COPD did not have a significantly greater number of positive reactions than horses without atopy at any time period for any allergen group (grasses, weeds, trees, molds, and insects).

Conclusions and Clinical Relevance—Positive results of IDT document allergen-specific hypersensitivity but do not necessarily distinguish clinically relevant reactions from subclinical reactivity in horses with COPD. Interpreting the clinical relevance of results of IDT requires a thorough knowledge of the medical history, physical examination findings, and environment of each animal. (Am J Vet Res 2001;62:389–397)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare a radioallergosorbent test and 2 ELISA with intradermal testing for the determination of environmental allergen hypersensitivity in horses with and without atopic diseases.

Design—Prospective clinical study.

Animals—10 horses with recurrent urticaria, 7 with atopic dermatitis, 16 with chronic obstructive pulmonary disease, and 22 without atopy.

Procedure—History, physical examination, hemogram, serum biochemical analyses, bronchoalveolar lavage, and an intradermal test (used as the criterion standard) with a regional panel of 73 allergens were performed in all horses. Serum was analyzed by use of the 3 in vitro assays of allergen-specific IgE.

Results—An ELISA based on the α chain of the highaffinity IgE receptor, the Fc∈ receptor immunoglobin ∈ chain (Fc∈RIα) for IgE, had the overall highest kappa statistic (0.238), positive predictive value (49%), and negative predictive value (78%). Overall agreement between the Fc∈RIα-based ELISA and the intradermal test was fair. The highest kappa statistic was obtained by the Fc∈RIα-based ELISA in horses with atopic dermatitis (0.330). Kappa statistics for the radioallergosorbent test and a polyclonal antibody-based ELISA agreed slightly with that of the intradermal test at best.

Conclusions and Clinical Relevance—None of the 3 serum allergy tests reliably detected allergen hypersensitivity, compared with the intradermal test. The Fc∈RIα-based ELISA performed significantly better overall than the other 2 tests. Low sensitivity of all 3 assays indicates the need for continued study to elucidate a more sensitive test for the determination of potentially pathogenic allergens in horses. (J Am Vet Med Assoc 2001;218:1314–1322)

Full access
in Journal of the American Veterinary Medical Association