Urodynamic and morphometric characteristics of the lower urogenital tract of male Beagle littermates from four months to two years of age

Abstract

OBJECTIVE To describe functional and anatomic changes of the lower urogenital tract of healthy male dogs during the sexually immature period and up to 2 years of age by urodynamic and morphometric assessment. ANIMALS 6 sexually intact male Beagle littermates. PROCEDURES Dogs underwent electromyography-coupled urodynamic tests, CT-assisted retrograde urethrography, prostatic washes, and blood sampling monthly from 4 through 12 months of age and then at 3-month intervals. Urodynamic and morphometric variables and serum canine prostate–specific esterase concentrations were analyzed by statistical methods. RESULTS Integrated pressure of the urethra was significantly increased beginning at 8 months of age, compared with earlier time points. Urethral pressure peak amplitudes varied among anatomic regions. During bladder filling, few electromyographic signals were concurrent with urethral pressure peaks; these were most commonly detected in the penile portion of the urethra. Urethral length and prostate gland volume were significantly greater from 7 to 24 months of age than at younger ages. Urethral length was approximately 26 to 27 cm after 9 months, and prostate gland volume was approximately 11 to 12 cm3 after 11 months of age. Serum canine prostate–specific esterase concentrations correlated with prostate gland volume. Urinary bladder threshold volume was significantly increased at 6 months of age, compared with that at 4 months, with a maximum of 197.7 mL at 24 months. CONCLUSIONS AND CLINICAL RELEVANCE Urethral resistance was acquired at approximately 8 months of age, when growth of the lower urinary tract was incomplete. Electromyographic and integrated pressure measurement results and the distribution and amplitude of urethral pressure peaks highlighted the potential role of the prostate gland and possibly the bulbocavernosus muscles in control of continence.

Electromyography of the External Anal Sphincter during Micturition and Electrophysiological Bulbocavernosus Reflex in Healthy Spayed Female Canines

“…The EBCR test was successfully performed in 10 spayed female canine subjects and was repeated to ensure reproducibility. The test of normality according to Anderson–Darling [ 16 ] demonstrated that EBCR onset latency revealed a Gaussian distribution ( P > 0.05), while the EBCR mean baseline to peak amplitude revealed a non-Gaussian distribution ( P < 0.05) ( Figure 5 ).…”

“…Te mean latency and standard deviation of EBCR in male and female Beagles were 24.42 ± 1.09 (range from 17.6 to 28.8) and 22.26 ± 1.92 (range from 18.99 to 25.69) milliseconds (ms), respectively [12,13]. Some studies in the past have reported the efects of sex hormones on neuromuscular function [14][15][16][17]; thus, this is possibly the frst study of EBCR in spayed female canines, owing to which estrous cycle was not afected.…”