Michael M. Warren

Recent advances in the diagnosis and treatment of renal arteriovenous malformations and fistulas

Arteriovenous malformations remain relatively rare clinical lesions. However, with an increasing number of percutaneous renal procedures being performed, their overall incidence can be expected to increase. Congenital arteriovenous malformations usually present with hematuria, while acquired fistulas are more likely to present with hemodynamic changes, such as hypertension, cardiomegaly and congestive heart failure. Arteriography remains the principal method of diagnosis. However, newer imaging modalities such as CT, MRI and color duplex ultrasound may make significant contributions in the evaluation of these abnormalities (fig. 1). Surgery, whether nephrectomy or ligation of feeding vessels, has long been the standard treatment for symptomatic arteriovenous malformations or fistulas. The loss of normal renal parenchyma, migration of occluding agents or recanalization of abnormal vessels has limited the use of embolization as a method of treatment in the past. Recently, newer techniques and agents, such as pharmacoangiography and alcohol, have increased the efficacy of embolization therapy, either as an adjuvant to surgery, definitive therapy or palliation. Although to our knowledge there have been no controlled studies comparing surgical treatment versus embolization, certain recommendations can be made. Because of the decreasing morbidity and increasing efficacy, embolization should be attempted at the time of arteriography as a means of treatment for most arteriovenous malformations and fistulas. However, the choice of surgery, embolization or a combination must be individualized for each patient with regard to overall health, symptoms and manifestations of the fistula or malformation (fig. 2).

Urothelial Hyperplasia and Neoplasia: A Response to Chronic Urinary Tract Infections in Rats

The rat was used as an animal model to examine the effect of foreign bodies and long term infection (24 weeks) on bladder epithelium. Stainless steel wire implants and multiple injections of Escherichia coli were compared to control rat bladders by gross observation, light microscopy and scanning electron microscopy. Hyperplastic alterations, (papilloma, von Brunns nests), dysplasia (squamous metaplasia, microvilli) and early lesions consistent with neoplasia occurred in rats with bladder implants and multiple bacterial injections but not in controls. Epithelial changes were not associated with sterile bladder implants. Bladder papillomata could be observed as early as 2 weeks in rats having both an implant and an infection, but the majority of hyperplastic and early neoplastic-like changes occurred after 6 weeks. Long-term infections, both with and without a bladder implant, can lead to lesions consistent with neoplasia in bladder epithelium.

Electrode and Bacterial Survival with Iontophoresis in Synthetic Urine

Urinary catheters, especially in patients with long-term catheter requirements, frequently are a source of infection. Iontophoresis has been proposed as a method to decrease or eliminate such infections. Several types of material were examined for their potential use as electrodes in an iontophoretic catheter system. Silver, copper and nickel electrodes did kill microorganisms but did not show longevity. Carbon and gold electrodes showed longevity and killing of microorganisms. Gold proved to be somewhat better than carbon in killing Klebsiella pneumoniae in a broth. Few organisms survived iontophoresis. Those few that survived (mainly Klebsiella in broth), when rechallenged by iontophoresis, did not show any striking resistance to iontophoresis. Our data support the proposition that inclusion of electrodes, depending on the electrode type, in a catheter probably will decrease or eliminate a bacterial population in urine and, thus, may help prevent catheter-related infections and their sequelae.

Endometriosis of bladder

A case is described of endometriosis of the bladder in a postmenopausal patient who had gross hematuria and pelvic mass. Medical treatment with progestins was unsuccessful, and a partial cystectomy was performed.

Histopathological Evaluation of Laser Thermocoagulation in the Human Prostate: Optimization of Laser Irradiation for Benign Prostatic Hyperplasia

We have previously shown in a canine prostate model that a noncontact low power neodymium:YAG laser regimen of 15 watts for 180 seconds yields a larger volume of coagulation necrosis than the currently recommended high power regimen of 50 watts for 60 seconds. These 2 regimens have not yet been compared in humans. The objective of this study was to evaluate histopathologically the thermocoagulation effect of these 2 laser regimens in the human prostate and the effect of the spatial distribution of the laser lesions on the extent of coagulation necrosis. The study was conducted in 10 patients undergoing radical prostatectomy or cystoprostatectomy. The laser treatment was given transurethrally 1 hour before removal of the specimen. There were no fractures of the prostate. The coagulation necrosis did not reach the peripheral zone and it was minimal in areas rich in fibromuscular tissue, such as the bladder neck. At times, nodular benign prostatic hyperplasia was unaffected. A 4-quadrant treatment in the same plane often yielded small nonconfluent lesions. Confluent lesions in the same plane yielded approximately 30% greater depth of coagulation necrosis, which was achieved when 3 or 4 lesions were created on each side of the prostate (per single transverse plane). Likewise, coagulation necrosis observed with 15 watts for 180 seconds was approximately 40% greater than that noted with the 50 watts for 60 seconds regimen. Our findings suggest that noncontact laser prostatectomy is a safe procedure that can be improved by modifying the laser regimen and the spatial distribution of lesions.

Papillary cystadenoma of epididymis: Component of von hippel-lindau syndrome

A case of epididymal cystadenoma, thought to be a component of the von Hippel-Lindau syndrome, is presented. The syndrome is reviewed, and the importance of long-term urologic follow-up for possible presentation of renal cell carcinoma is discussed.

In Vivo Reduction of Bacterial Populations in the Urinary Tract of Catheterized Sheep by Iontophoresis

PURPOSE Iontophoresis kills microbes in vitro and, therefore, may be a useful method for eliminating microbial populations associated with catheter-induced urinary tract infections in vivo. MATERIALS AND METHODS Catheters were modified to deliver current to platinum electrodes in the catheter tip. Female sheep were catheterized with this iontophoretic catheter and left ambulatory. In 5 sheep (experimental group) 400 microA was applied to the catheter and withheld in 4 sheep (control group) for 20 to 21 days. The animals were then sacrificed. During the study, types and concentrations of bacteria, and physical and chemical characteristics of the urine samples were determined. RESULTS Throughout the study, bacteria levels were reduced in urinary tracts of the experimental group (10(3) to 10(4) microbes per ml.) compared with the control group (10(7) microbes per ml.), without extensive alterations to urine chemistry or the sheep urinary tract. CONCLUSIONS Since iontophoresis safely reduced bacterial populations in catheterized sheep, this technology may reduce or eliminate nosocomial, catheter-induced urinary tract infections in humans.

Urothelial Hyperplasia and Neoplasia. II. Detection of Nitrosamines and Interferon in Chronic Urinary Tract Infections in Rats

In rats with chronic urinary tract infections, urine and blood were examined for two classes of compounds (nitrosamines and interferon) which may lead to the development of urothelial hyperplasia and neoplasia. In vitro, Escherichia coli, a Proteus species or a mixture of both were able to induce high levels of interferon which theoretically could reduce the hosts cellular immune surveillance. These high levels were not detected in vivo in either short-term (5 hr. to 2 wk.) or long-term (2 wk. to 24 wk.) infected rats. In contrast, N, N dimethylnitrosamine was detected in the majority (greater than or equal to 50 per cent) of long term infected rats after 12 wk. although individual rats showed detectable levels as early as 2 wk. post infection. Sterile human or rat urine supported bacterial growth and subsequent production of N, N dimethylnitrosamine, but only after 16 wk. of subculturing in vitro. Gas chromatography was able to detect small amounts of nitrosamines extracted from urine. The mass spectrometer yielded quantitatively and qualitatively better detection. With long term infections, the appearance of a potential carcinogen, N, N dimethylnitrosamine, occurs in vivo and in vitro and correlates with previous findings that describe the development of hyperplastic and early neoplastic changes in the rat urothelium.

Stone Formation on Polypropylene Suture

Polypropylene is a relatively new suture material with many advantages, which has been demonstrated in experimental studies to be a safe material for urologic operations. However, recently, 2 patients had polypropylene suture at the matrix of urinary calculi. Symptoms from the calculi developed in both patients in the late postoperative period and both had large amounts of fibrosis around the sutured urothelium.

Mesonephric adenocarcinoma of bladder

Mesonephric adenocarcinoma of the bladder is an unusual tumor, with its origin unclear. Metaplasia of urothelium and anaplasia of embryonic cell rests appear to be the cause of this tumor. A patient is described with mesonephric adenocarcinoma, who is now apparently free of disease two years after a radical cystectomy and ileal conduit. This represents the second such report in the literature.