Faculty Bibliography

We study the stretch flow of a thin layer of Newtonian liquid constrained between two circular plates. The evolution of the interface of the originally circular bubble is studied when lifting one of the plates at a constant velocity and the observed pattern is related to the measured lifting force. By comparing experimental results to numerical simulations using a Darcy's law model we can account for the fully nonlinear evolution of the observed fingering pattern. One observes an initial destabilization of the interface by growth of air fingers due to a Saffman-Taylor-like instability and then a coarsening of the pattern toward a circular interface until complete debonding of the two plates occurs. Numerical simulations reveal that when relating the observed patterns to the lifting force not only the number of fingers but also the amplitude of the fingering growth has to be taken into account. This is consistent with the experimental observations. (c) 2005 American Institute of Physics.

OBJECTIVES: We determined whether patient mobilization influences ureteral catheter position in the collecting system. METHODS: 26 consecutive patients (28 renal units) who underwent ureteral catheterization for the purpose of retrograde pyelography or the relief of ureteral obstruction, were included. The position of the catheter's tip within the collecting system and versus the vertebrae was determined for each patient in the baseline supine position; standing upright, and supine again after walking a distance of 5 m. Catheteral displacement was determined by comparing its position in the upright and supine post-walking postures to its original position with the patient supine before any maneuver was undertaken. RESULTS: Assuming the upright position caused an average downward displacement of ureteral catheters by 7.8 mm (ranges 36 mm downward to 14 mm upward displacements, p = 0.0014). In the supine posture following a 5-meter walk, the catheters were downward displaced by 0. 36 mm on average (ranges 12 mm downward and 30 mm upward displacements p = 0.8). None of the ureteral catheters migrated below the uretero-pelvic junction during any phase of the above maneuvers. CONCLUSION: The position of ureteral catheters remains unchanged within the collecting system when patients stand or walk for 5 m. Therefore, mandatory bed restriction is not justified in patients with ureteral catheters.

Inflammatory bowel disease exhibits a bimodality in age-specific incidence rates, with the second peak occurring from 60 to 70 years of age. In the elderly, both ulcerative colitis and Crohn's disease tend to involve the left side of the colon. The course of disease and the basic principles of management in geriatric populations do not differ from those in younger patients; however, elderly patients do pose distinct problems in differential diagnosis and in therapy choice

Radical prostatectomy is associated with difficulty in determining the division site of the urethra adjacent to the apical region of the prostate. We present the results of a feasibility clinical trial in three patients to determine whether intraoperative transrectal ultrasonography may assist during radical retropubic prostatectomy. Using this technique the apex is readily identified and a detailed view of the urethral stump could be obtained. In one case residual apical tissue was identified and excised. The creation of the vesicourethral anastomosis was documented and its water tightness was demonstrated. We conclude that transrectal ultrasonography can be performed during radical retropubic prostatectomy and may be helpful in selected cases.

Prostatic cysts are common and are usually acquired and asymptomatic. Congenital prostatic cysts, which may originate from the wolffian system or from remnants of the Muellerian duct, are rare and may cause obstructive symptoms in young adults. Due to the availability of transrectal ultrasonography an increased number of cases of prostatic cysts are being diagnosed. We report a 36-year-old man with a congenital prostatic cyst which caused increasing pain during ejaculation and decreased the force of the urinary stream. It was diagnosed by ultrasonography and treated successfully by ultrasound-controlled, transrectal needle aspiration. There was immediate, complete disappearance of symptoms and no complications.

A case of a possible primary carcinoid tumor of the skin in a 40-year-old man is presented. The neoplasm was diagnosed as consistent with carcinoid tumor on the basis of conventional light microscopy, immunohistochemical studies, and electron microscopy. Workup revealed no evidence of carcinoid tumor elsewhere. Metastases to the skin from internal carcinoid tumors are uncommon, but presumed primary carcinoid tumors that arise in the skin are extremely rare; only three cases have been found in the English-language literature