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Abstract

Objective

To compare therapeutic benefits of intratumoral administration of cisplatin and bleomycin for squamous cell carcinoma of the eyelids in horses.

Animals

25 horses with 27 T2-stage periocular squamous cell carcinomas.

Procedure

Horses were treated 4 times at 2-week intervals with a slow-release formulation of cisplatin (1 mg/cm3 of tissue) or bleomycin (1 IU/cm3 of tissue). A two-stage design was used to minimize the sample size in each treatment arm.

Results

The local control rate at 1 year for lesions treated with cisplatin was 93 ± 6%, and with bleomycin was 78 ± 10%. Difference in local control duration between the 2 treatment groups was not significantly different. A high tumor proliferative fraction index value was associated with a higher local (in-field) control rate, but also with a higher risk of marginal and regional recurrences. Tumors with a low proliferative fraction index value (< 28%) had 9.5-times higher (P = 0.0411) risk of recurrence than those with a high index value. Local acute reactions were similar in the 2 treatment groups, and chronic reactions were not observed.

Conclusions

Cisplatin and bleomycin were effective anticancer agents for carcinoma of the eyelid in horses. Based on therapeutic benefit and treatment cost, cisplatin was found to be a better choice for intratumoral chemotherapy of eyelid carcinomas.

Clinical Relevance

Results of this study confirm the value of intratumoral chemotherapy, using cisplatin, for treatment of cutaneous squamous cell carcinomas in horses. (Am J Vet Res 1997;58:431–436)

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

Objective—To develop and use a sensitive molecular assay for detecting the phospholipase D (PLD) exotoxin gene of Corynebacterium pseudotuberculosis in an attempt to identify insect vectors that may be important in transmission of clinical disease in horses.

Sample Population—2,621 flies of various species.

Procedure—A real-time polymerase chain reaction (PCR)-based fluorogenic 5' nuclease (TaqMan) system (ie, TaqMan PCR assay) was developed for the detection of the PLD gene in insects. Flies were collected monthly (May to November 2002) from 5 farms in northern California where C pseudotuberculosis infection in horses is endemic. Three of the 5 farms (which housed a total of 358 horses) had diseased horses during the study period. A total of 2,621 flies of various species were tested for the PLD gene of C pseudotuberculosis.

Results—Evidence of bacterial DNA for the PLD gene was detected in skin biopsy specimens from clinically affected horses and from 3 fly species collected from farms where affected horses were housed. Farms with a high incidence of diseased horses had a high proportion of insects carrying the organism. High percentages of flies with positive results for the PLD gene were observed in October, when most clinically affected horses were observed.

Conclusions and Clinical Relevance—Our results are consistent with the hypothesis that C pseudotuberculosis may be vectored to horses by flies. Three potential vectors were identified, including Haematobia irritans, Stomoxys calcitrans, and Musca domestica. The organism can be identified in up to 20% of house flies (Musca domestica) in the vicinity of diseased horses. (Am J Vet Res 2004;65:829–834)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To test the hypothesis that application of a rope restraint device would result in behavioral, electroencephalographic, and humoral changes consistent with sleep and analgesia in neonatal foals.

Animals—8 healthy neonatal foals.

Procedures—Following acclimatization to experimental conditions, each foal underwent a series of assessments before and during or at the end of a period of restraint via application of a restraint device (soft linen rope). Assessments included measurements of heart and respiratory rates, rectal temperature, and circulating β-endorphin and steroid hormone concentrations and evaluations of mentation and body position (behavior), electroencephalographic patterns, and pain tolerance.

Results—All foals were lively with apparently normal behavior prior to restraint. During application of the restraint device, foals assumed lateral recumbency with relaxed, somnolent behavior. Heart and respiratory rates and rectal temperature uniformly decreased as a result of the procedure. Electroencephalographic recordings (completed for 3 foals only) revealed patterns consistent with slow wave sleep. Plasma ACTH, dehydroepiandrosterone sulfate, and androstenedione concentrations significantly increased during restraint, compared with prerestraint values. The foals' tolerance to noxious stimuli significantly increased during restraint; however, this was independent of the concentration of circulating β-endorphin.

Conclusions and Clinical Relevance—In neonatal foals, the evaluated form of restraint resulted in a decrease in heart and respiratory rates and rectal temperature. Squeeze-induced somnolence may resemble the effects of compression of the fetus in the birth canal and lead to inhibition of voluntary activity. Use of this technique to safely restrain neonatal foals during minor procedures warrants further evaluation.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine susceptibility of cattle to infection with Ehrlichia equi and the agent of human granulocytic ehrlichiosis (HGE).

Design—Experimental disease and prevalence survey.

Animals—6 cattle, 2 horses, and 2,725 serum samples from healthy cattle.

Procedure—2 cattle and 1 horse were inoculated with E equi, 2 cattle and 1 horse were inoculated with the HGE agent, and 2 cattle served as sham-inoculated controls; inoculated animals were evaluated via clinical, hematologic, serologic, and real-time polymerase chain reaction tests. Prevalence of antibodies against E equi in 2,725 healthy cattle was determined by use of an indirect immunofluorescent technique.

Results—No abnormal clinical or hematologic findings or inclusion bodies within granulocytes were observed in the cattle after inoculation, and results of all polymerase chain reaction tests were negative. Seroconversion in inoculated cattle developed 10 to 12 days after inoculation (reciprocal titers, 160). Both horses developed clinical signs of ehrlichiosis. Five of 2,725 (0.18%) cattle were seropositive for E equi, with titers ranging from 20 to 80. All seropositive cattle originated from the same tick-rich region in the Sierra Nevada foothills.

Conclusions and Clinical Relevance—Results suggest that cattle are not susceptible to infection with E equi or the agent of HGE and that prevalence of exposure to E equi in healthy cattle is low. Therefore, E equi and the agent of HGE are likely of negligible importance for cattle in North America. (J Am Vet Med Assoc 2001;218:1160–1162)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Case Description—A 15-year-old Saddlebred gelding used for competitive pleasure driving had a 1-year history of head shaking while pulling a cart.

Clinical Findings—The horse had cystic corpora nigra in both eyes and concomitant classic and operant conditioned responses to wearing a bridle with bilateral eye covers (blinkers).

Treatment and Outcome—Deflation and coagulation of the cysts with an infrared diode laser and behavior modification consisting of desensitization and counterconditioning were used to successfully restore performance.

Clinical Relevance—Behavioral changes in horses can result from a combination of physical and psychologic causes. A combination of appropriate medical treatment of physical abnormalities and a behavioral modification plan is necessary to successfully treat behavioral problems in these patients.

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

The effects of 2 liquid formula diets differing in protein source were evaluated in orphan foals. The response of 7 foals fed a diet containing casein as the protein source, and 6 foals fed a diet containing a combination of whey and casein, was compared with the response in a reference group of 8 mare-raised foals. Orphaned foals were fed 150 kcal/kg of body weight/d, divided into 6 equal feedings of 25 kcal/kg. Formula intake was comparable among the experimental groups, and foals fed the liquid formula diet grew as well as mare-raised foals. There was no difference among groups in mean daily body weight gain, wither height, heart girth, body temperature, pulse, respiration rate, capillary refill time, or skin tenting. Insulin and blood glucose concentrations increased in both groups of foals fed formula diets, returning to prefeeding values within 4 hours. Differences among groups were found for serum alkaline phosphatase, alanine transaminase, cholesterol, creatinine, and glucose values; all other serum chemical values were comparable among groups. Plasma amino acid determinations revealed that arginine and ornithine were significantly lower in foals in both experimental groups than in reference foals, suggesting that arginine may have been the limiting amino acid in these diets. Diarrhea developed in foals in all treatment groups, but in most cases was self-limiting. These results suggest that the protein source of liquid formula diets may be less important in foals than in infants.

Free access
in American Journal of Veterinary Research

Objective

To determine whether dogs living in tick-infested areas of the northeastern United States had been exposed to Ehrlichia equi, an etiologic agent of granulocytic ehrlichiosis.

Design

Analyses of dog sera.

Animals

106 ill dogs and 12 clinically normal dogs.

Procedure

Antibodies to E equi were detected by indirect fluorescent antibody staining methods and western blot analyses.

Results

10 of 106 (9.4%) sera tested from ill, privately owned dogs living in tick-infested areas of Connecticut and New York state had antibodies to E equi, a member of the E phagocytophila genogroup. Titration end points ranged from 1:80 to 1:1,280. Immunoblots revealed antibodies to proteins of E equi having molecular masses of predominantly 29, 40, 44, 105, 120, and 160 kd. There was good agreement between results of serologic testing methods, but use of the human isolate (NCH-1 strain) in western blot analyses detected 2 additional seropositive dogs found to be negative by indirect fluorescent antibody staining methods with the MRK strain.

Clinical Implications

Dogs living in areas where Ixodes scapularis is abundant may be exposed to multiple pathogens, such as E equi or Borrelia burgdorferi. Although mild or subclinical infections with E equi may develop, dogs with marked leukopenia, thrombocytopenia, or anemia should be viewed as possibly having ehrlichiosis. Laboratory diagnosis should include examinations for morulae in granulocytes or monocytes in addition to serologic analyses. (J Am Vet Med Assoc 1997;211:1134–1137)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To describe epidemiological, clinical, and pathological features of neuroaxonal dystrophy in Quarter Horses (QHs) on a single farm.

Design—Prospective case series.

Animals—148 horses.

Procedures—Neurologic, pathological, and toxicological evaluations were completed in selected neurologically affected horses over a 2-year period. Descriptive statistical analysis was performed.

Results—87 QHs and 1 QH-crossbred horse were affected. Most (50/88 [56.8%]) affected horses were 1 to 2 years old (median age, 2 years [range, 2 months to 34 years]). Neurologic deficits included obtundation (53/88 [60%] horses), decreased to absent menace response (33/88 [37.5%]), proprioceptive positioning deficits, wide-based stance, ataxia, and dysmetria (88/88 [100%]). Most (78/88 [88.6%]) horses had mild ataxia, but some (10/88 [11.4%]) had moderate to severe ataxia. Low serum concentrations of vitamin E (≤ 2 mg/L) were detected in 3 index case horses and 16 of 17 randomly selected horses (13/14 affected and 3/3 unaffected) during study year 1. Dietary vitamin E supplementation did not improve neurologic deficits in affected horses; vitamin E administration in pregnant mares appeared to decrease but not prevent disease development among offspring born the following year. Lesions detected at necropsy included bilaterally symmetric neuroaxonal degeneration with axonal spheroids in the nucleus gracilis, nucleus cuneatus medialis, nucleus cuneatus lateralis, and nucleus thoracicus (5/5 horses).

Conclusions and Clinical Relevance—Neuroaxonal dystrophy should be considered in evaluation of young horses with ataxia and proprioceptive positioning deficits. Vitamin E deficiency may contribute to disease severity.

Full access
in Journal of the American Veterinary Medical Association