The effect of Pueraria mirifica on cytologic and urodynamic findings in ovariectomized rats.

OBJECTIVE: To evaluate the effect of Pueraria mirifica on vaginal and urethral cytology, bladder pressure and capacity, residual urine, and leak point pressure in ovariectomized rats. METHODS: Seventy-two adult, ovariectomized, female Sprague-Dawley rats were placed into one of four groups: control, estradiol, or 100 or 1,000 mg/kg of Pueraria mirifica (PM-100 and PM-1000, respectively). The vaginal and urethral smears were checked after 30 days of ovariectomy at pretreatment and at day 28 of treatment.A single cystometry, defined as the micturition interval, filling pressure, threshold pressure, micturition pressure, and voided volume, was performed. Peak bladder pressure was calculated for each leak point pressure measured at half bladder capacity by slowly and manually increasing abdominal pressure until a leak occurred, at which point external pressure was rapidly released. Leak point pressure was tested three times per rat. RESULTS: After 28 days of treatment, the estradiol, PM-100, and PM-1000 groups had significantly higher numbers of vaginal and urethral superficial cells compared with the control group (P < 0.05). Regarding the urodynamic parameters, the threshold pressure, micturition pressure, and leak point pressure were higher in the estradiol, PM-100, and PM-1000 groups compared with the control group (P < 0.05). The control, PM-100, and PM-1000 groups had the same values for micturition interval, bladder capacity, voided volume, and residual volume (P > 0.05) but lower values compared with the estradiol group (P < 0.05). CONCLUSIONS: Pueraria mirifica 100 and 1,000 mg/kg/day showed an estrogen-like effect on the vaginal and urethral epithelium of ovariectomized rats. They did not change bladder capacity and residual urine volume but increased leak point pressure according to urodynamic study.

Methylene blue staining for nerve-sparing operative procedures: an animal model.

OBJECTIVES: To evaluate methylene blue fiber staining as a method of nerve fiber identification in an animal model, because the maintenance of organ function after surgery depends on exact intraoperative identification of the relevant nerve fibers. METHODS: Brindley electrodes were implanted bilaterally at S3 for sacral anterior root stimulation in six minipigs. For reference, stimulation-induced detrusor contractions were recorded urodynamically. After exposure of the ureterovesical junction on both sides, a 2:8 methylene blue solution was applied to the right side; the left side remained untreated. Bilateral dissection of the ureter from the surrounding tissue for a distance of 4 cm proximal to the ureterovesical junction was performed. The methylene blue-stained nerve fibers on the right side were spared; no particular attention was paid to the nerves on the left. Again, sacral anterior root stimulation-induced detrusor contractions were monitored urodynamically on both sides. Then, the identified nerve fibers on the right were cut intentionally, and the detrusor pressure was recorded again under stimulation. Finally, the dissected nerve structures were evaluated histologically. RESULTS: The reference bladder pressures after unilateral stimulation on the left side before ureter dissection showed a mean detrusor pressure (Pdet) of 19 cm H2O. On the right side, the Pdet was 18 cm H2O. After preparation on both sides, a mean Pdet of 3 cm H2O was recorded after left side stimulation, and a Pdet of 17 cm H2O after right side stimulation. When the stained nerve fibers on the right side were cut, no bladder contractions could be induced. The histomorphology of the stained and dissected structures revealed multiple autonomous nerve fibers and small vessels in connective tissue. CONCLUSIONS: The identification of minute nerve bundles is a tedious and difficult task. The results from our animal model demonstrated that supravital staining of autonomous nerve fibers with methylene blue is a simple and reliable method of identification.

Risk of detrusor denervation in antireflux surgery demonstrated in a neurophysiological animal model.

PURPOSE: Earlier anatomical studies have shown a close connection between the ureterovesical junction and detrusor innervation. It prompted us to develop an animal model to demonstrate the risk of partial or complete impairment of this neuronal connection during antireflux surgery. MATERIALS AND METHODS: Six female Göttinger minipigs were anesthetized and laminectomized. After placement of the S3 sacral nerves into separate electrode compartments of a modified Brindley electrode the lower urinary tract was exposed by an abdominal midline incision. After bladder instillation with 150 ml NaCl 1 bilateral and 2 unilateral stimulations (left and right sides) were performed and intravesical pressure was recorded urodynamically. The left ureter was then prepared circularly in 3 steps 10, 5 and 1 cm, respectively, proximal to the ureterovesical junction. After each preparation step bilateral and unilateral stimulation was repeated. Results were recorded urodynamically and video documented. RESULTS: Bilateral stimulation before preparation of the left ureter led to a concentric detrusor contraction with an average maximum detrusor pressure of 51 cm H(2)O. Unilateral stimulation resulted in ipsilateralbound bladder tilting with an intravesical pressure of 18 and 19 cm H(2)O on the right and left sides, respectively. After preparation of the left ureter 10, 5 and 1 cm from the ureterovesical junction a maximum detrusor pressure of 17, 10 and 1 cm H(2)O was documented, respectively. While there was almost no stimulation response of the bladder after the last preparation step at 1 cm on the left ureter, the initial bladder pressure of 18 cm H(2)O could be reproduced under stimulation on the right side. CONCLUSIONS: Analogous to human cadaver studies, we were able to prove neurophysiologically strictly unilateral detrusor innervation, drawing from the pelvic plexus dorsomedial to the ureterovesical junction into the bladder. Preparation of this ureterovesical junction during antireflex surgery, coagulating measures in this area or the affixation of anchor sutures after a Vest suture involves the risk of unilateral or bilateral detrusor decentralization.