Search Results

Abstract

Objective—To determine the relationship between plasma β-endorphin (EN) concentrations and exercise intensity and duration in horses.

Animals—8 mares with a mean age of 6 years (range, 3 to 13 years) and mean body weight of 450 kg.

Procedure—Horses were exercised for 20 minutes at 60% of maximal oxygen consumption (O₂max) and to fatigue at 95% O₂max. Plasma EN concentrations were determined before exercise, after a 10- minute warmup period, after 5, 10, 15, and 20 minutes at 60% O₂max or at the point of fatigue (95% O₂max), and at regular intervals after exercise. Glucose concentrations were determined at the same times EN concentrations were measured. Plasma lactate concentration was measured 5 minutes after exercise.

Results—Maximum EN values were recorded 0 to 45 minutes after horses completed each test. Significant time and intensity effects on EN concentrations were detected. Concentrations were significantly higher following exercise at 95% O₂max, compared with those after 20 minutes of exercise at 60% O₂max (605.2 ± 140.6 vs 312.3 ± 53.1 pg/ml). Plasma EN concentration was not related to lactate concentration and was significantly but weakly correlated with glucose concentration for exercise at both intensities (r = 0.21 and 0.30 for 60 and 95% O₂max, respectively).

Conclusions and Clinical Relevance—A critical exercise threshold exists for EN concentration in horses, which is 60% O₂max or less and is related to exercise intensity and duration. Even under conditions of controlled exercise there may be considerable differences in EN concentrations between horses. This makes the value of comparing horses on the basis of their EN concentration questionable. (Am J Vet Res 2000;61:969–973)

Abstract

Objective—To evaluate the ability of various subjective and objective measurements to determine the presence and degree of postoperative pain in cats.

Design—Randomized controlled prospective clinical study.

Animals—18 healthy client-owned cats.

Procedure—Cats were randomly assigned to 3 groups of 6: control, tenectomy, and onychectomy. Jugular catheters were placed the day prior to surgery. All surgeries were performed by the same surgeon, and all observations were made by the same blinded trained observer. One hour prior to surgery and at assigned intervals for 36 hours after surgery, heart rate, respiratory rate, and rectal temperature were measured. Scores were assigned for 3 interaction responses, including response to palpation, by use of simple descriptive scales, and to 2 pain assessments by use of visual analogue scales. Blood was collected to measure plasma β-endorphin and cortisol concentrations. Butorphanol was administered to all cats before surgery and to any cat subjectively assessed to be experiencing pain after surgery.

Results—Only visual analogue scale scores and response to palpation scores differed significantly between control and surgical groups.

Conclusions and Clinical Relevance—Determination of the presence of pain in cats can be made on the basis of observation and interaction by a trained observer. Physiologic measurements, including plasma cortisol and β-endorphin concentrations, did not differentiate between control cats and cats that underwent surgery. (J Am Vet Med Assoc 2000; 217:685–690)

Abstract

Objective—To determine the effect of finasteride on programmed cell death (apoptosis) of prostatic cells during prostatic involution in dogs with benign prostatic hypertrophy (BPH).

Animals—9 dogs with BPH.

Procedure—Dogs were randomly assigned to treatment or control groups. Treatment dogs (n = 5) were administered finasteride (0.1 to 0.5 mg/kg, PO, q 24 h) for 16 weeks, whereas the 4 control dogs were administered an inert compound. Prostatic cells from the prostatic fluid portion of the ejaculate of treatment and control dogs were obtained before and 1, 2, 3, 4, 8, and 16 weeks after initiation of treatment. Cells were concentrated by use of centrifugation. Prostatic cells were examined for indications of apoptosis by use of a terminal deoxyribonucleotidyl transferase- mediated deoxyuracil triphosphate nick-end labeling technique. After receiving the inert compound for 16 weeks, the 4 control dogs were administered finasteride for 16 weeks, and evaluations were repeated.

Results—Percentage of apoptotic prostatic cells in ejaculated prostatic fluid of treatment dogs increased significantly (from 9% before treatment to 33, 31, 26, and 27% after 1, 2, 3, and 8 weeks of treatment, respectively). There was no significant change in percentage of apoptotic prostatic cells in the ejaculated prostatic fluid of control dogs.

Conclusions and Clinical Relevance—Finasterideinduced prostatic involution appears to be via apoptosis in dogs with BPH. Finasteride treatment of dogs with BPH causes prostatic involution by apoptosis rather than necrosis. (Am J Vet Res 2002;63:495–498)

Abstract

Objective—To determine the effect of the 5α-reductase inhibitor finasteride on prostatic diameter and volume, semen quality, and serum dihydrotestosterone (DHT) and testosterone concentrations in dogs with spontaneous benign prostatic hypertrophy (BPH).

Design—Double-blind placebo-controlled trial.

Animals—9 dogs with BPH.

Procedure—Five dogs were treated with finasteride for 16 weeks (0.1 to 0.5 mg/kg [0.05 to 0.23 mg/lb] of body weight, PO, q 24 h); the other 4 received a placebo. Prostatic diameter, measured radiographically, prostatic volume, measured ultrasonographically, semen quality, and serum DHT and testosterone concentrations were evaluated before and during treatment. After receiving the placebo for 16 weeks, the 4 control dogs were treated with finasteride for 16 weeks, and evaluations were repeated.

Results—Finasteride significantly decreased prostatic diameter (mean percentage decrease, 20%), prostatic volume (mean percentage decrease, 43%), and serum DHT concentration (mean percentage decrease, 58%). Finasteride decreased semen volume but did not adversely effect semen quality or serum testosterone concentration. No adverse effects were reported by owners of dogs in the study.

Conclusions and Clinical Relevance—Results suggest that finasteride can be used to reduce prostatic size in dogs with BPH without adversely affecting semen quality or serum testosterone concentration. (J Am Vet Med Assoc 2001;218:1275–1280)