Clinical problem-solving. Heart or head?
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Aged↗
Biomedical subjects
D M Barrett
Publications and source records attributed to D M Barrett.
Repeated pressure-flow studies in the evaluation of bladder outlet obstruction due to benign prostatic enlargement. Finasteride Urodynamics Study Group.
Test-retest reliability of repeated voids in pressure-flow studies and the influence on maximum flow rate (Q(max)pQ), detrusor pressure at maximum flow rate (p(det)Qmax), voided volume, and residual urine were studied. Also the agreement in interpretation of pressure-flow tracings between investigators and a single blinded central reader acting as a quality control center (QCC) were assessed. In addition, correlations between p(det)Qmax and patient age, International Prostate Symptom Score (IPSS), free maximum flow rate (Qmax), and prostate volume were calculated. Using suprapubic pressure recording, 216 men with lower urinary tract symptoms (LUTS) due to benign prostatic enlargement (BPE) were investigated in 11 centers. In each pressure-flow study, three sequential voids were performed, and quality controlled recordings were analyzed for Q(max)pQ and p(det)Qmax by the QCC. Trans rectal ultrasound was used to measure the prostate volume. Mean Q(max)pQ did not change, but p(det)Qmax decreased significantly in the second and third sequential voids. Using the Abrams-Griffiths nomogram definition of obstruction, 125 patients (67%) were classified as obstructed from the first void, but only 111 patients (59%) from the third void. The agreement between the investigator assessment and that of a single blinded reader was good. There was no significant correlation between p(det)Qmax and patient age, IPSS, and Qmax, whereas a modest correlation was found between p(det)Qmax and prostate volume. In summary, there was no significant change in Q(max)pQ, but p(det)Qmax decreased for the three consecutive voids, which can be explained by a decrease in outlet resistance. The agreement between the investigator and QCC interpretations shows the value of a standardized technique, supporting the feasibility of multicenter urodynamic studies. There is a modest, but statistically significant, correlation between detrusor pressure and prostate size, supporting the hypothesis that prostate size is a contributing factor in symptomatic BPH.
Adult↗
A new temporary catheter (ContiCath) for the treatment of temporary, reversible, postoperative urinary retention.
OBJECTIVES: To describe the initial experience of a newly designed temporary urethral catheter, ContiCath, as an aid in the management of postoperative or temporary outflow obstruction. In patients with normal detrusor and sphincter function, this catheter allows volitional voiding while maintaining an open prostatic urethra. METHODS: In a pilot study, 64 nonconsecutive patients with postoperative or temporary urinary retention, at eight clinical trial sites, were enrolled for the placement of this temporary catheter. Three patients did not have the catheter placed because of placement failure because of either a large median lobe or a urethral stricture. The remaining 61 patients were divided into three groups: those with non-neuropathic causes of retention and retention for 1 week or less (37 patients), those with non-neuropathic causes of retention and retention for longer than 1 week (19 patients), and those with neuropathic causes of retention and retention for longer than 1 week (5 patients). The ContiCath is placed in the office setting, in the same fashion as a Foley catheter. A blue prolene tether extends from the bulbar urethra to the meatus to assist in the removal of the device. Patients were then reassessed at 3 hours, and at 7, 14, 21, and 28 days, at which point the device was removed. RESULTS: In patients with a neuropathic cause for their retention (5 patients) and those with non-neuropathic causes of retention and retention for longer than 1 week (19 patients), only 3 patients were able to void after the catheter was placed. Of the 37 patients with a non-neuropathic cause and retention 1 week or less, controlled voiding was seen in 33 patients (89%). Controlled voiding was defined as the patient's volitional ability to initiate and stop his urinary stream. There were no complications with catheter placement; however, 8 patients (24.2%) had minor adverse experiences of frequency/urgency (n = 3), incontinence (n = 3), migration of the catheter (n = 1), and pain (n = 1). CONCLUSIONS: ContiCath offers an alternative to an indwelling Foley catheter in men with temporary bladder outlet obstruction and urinary retention.
Aged↗
Continued improvement in pressure-flow parameters in men receiving finasteride for 2 years. Finasteride Urodynamics Study Group.
OBJECTIVES: To assess the long-term effects of finasteride on pressure-flow parameters in men with urodynamically documented bladder outflow obstruction (BOO). METHODS: One hundred twenty-one men with benign prostatic enlargement (BPE) and lower urinary tract symptoms (LUTS) underwent a pressure-flow study (PFS) at 1 of 11 clinical centers. The PFS technique was standardized, and all tracings were read by a single reader unaware of the treatment group. Patients who were obstructed according to a modified Abrams-Griffiths nomogram were randomized to 5 mg finasteride (n = 81) or placebo (n = 40) for 12 months; all patients continuing into an open extension received finasteride during the second 12 months of therapy. Results of the initial 12-month study demonstrated the benefit of finasteride treatment on PFS parameters. To examine the continuing effects over time, an analysis of the data from 54 patients who completed 24 months of treatment with finasteride is provided. RESULTS: Detrusor pressure at maximum flow (PdetQmax) continued to decrease during the second 12 months of therapy (decreases of 5.3 and 11.7 cm H2O at months 12 and 24, respectively). The percentage of patients obstructed by Abrams-Griffiths classification decreased from 76.2% at baseline to 66.7% at month 12 and 59.6% at month 24. An intention-to-treat analysis yielded similar results. CONCLUSIONS: Finasteride improves urodynamic measures of obstruction in men with BPE and LUTS, with continued improvement during the second 12 months of therapy.
Double-Blind Method↗
Transforming growth factor-beta1 (TGF-beta1) is sufficient to induce fibrosis of rabbit corpus cavernosum in vivo.
PURPOSE: The pleotropic cytokine TGF-beta1 which induces connective tissue synthesis, and inhibits the growth of smooth muscle cells, has been implicated in corpus cavernosum fibrosis. The objective of this study was to determine the dose and time dependence of TGF-beta1 as an active agent in penile corporal fibrosis in an animal model. MATERIALS AND METHODS: A time release method of delivery was developed using sodium alginate microspheres containing recombinant human (rh) TGF-beta1. New Zealand White rabbits were injected intracorporally with a single alginate microsphere either with or without rh-TGF-beta1. Dosage was varied from 325 to 1500 ng./bead. Animals were sacrificed at either three or five days post injection and the penises removed en bloc, examined, and processed for quantitative histomorphometric analysis, staining the sections with Masson's trichrome. RESULTS: Alginate microspheres containing [125I]-rh-TGF-beta1 showed slow-release kinetics (t1/2 = 10.5 hours). Histomorphometric analysis of 60 sets of high powered fields/treatment/ animal showed dose dependent decreases in percentage of corporal smooth muscle with TGF-beta1 treatment (750 to 1500 ng./bead). Placebo (alginate microspheres alone) had trabecular smooth muscle content comparable to values previously reported for untreated rabbit corpus cavernosum. CONCLUSIONS: This study confirms that TGF-beta1 induces fibrosis in situ by altering connective tissue synthesis and hence the structure of the corpus cavernosum. Injection of rh-TGF-beta1 impregnated alginate microspheres into the corpus cavernosum resulted in dose-dependent decreases in percentage of corporal smooth muscle.
Animals↗
Pharmacotherapeutic advances in the treatment of erectile dysfunction.
An estimated 20 million to 30 million American men have erectile dysfunction (ED). The past 2 decades of research defining erectile physiology and investigating the pathogenesis of ED have led to the recognition of a predominantly vascular basis for organic male sexual dysfunction. These scientific advances have laid the foundation for the advent of pharmacotherapies. The Food and Drug Administration approval of intracavernosal, intraurethral, and oral pharmacotherapeutics for ED has revolutionized non-surgical management of this condition. The primary care physician is faced with the challenges of diagnosis and treatment of ED, as well as referral of patients to urologists. In this article, erectile physiology and pathophysiology are reviewed, and pharmacotherapeutics are classified and discussed by their mechanisms of action and the means of administration. A thorough understanding of these new therapeutic options is key to the accurate diagnosis and successful treatment of ED and maximal patient satisfaction and care.
Adrenergic alpha-Antagonists↗
Improvement of pressure flow parameters with finasteride is greater in men with large prostates. Finasteride Urodynamics Study Group.
PURPOSE: We assess the effect of finasteride, a 5alpha-reductase inhibitor, on objective voiding parameters in men with lower urinary tract symptoms and benign prostatic enlargement on digital rectal examination (known as clinical benign prostatic enlargement) in a double-blind placebo controlled multicenter study using strict standard pressure flow study techniques. MATERIALS AND METHODS: A modification of the Abrams-Griffiths nomogram was used by 1 reader to ensure that all patients met objective criteria for bladder outlet obstruction at baseline. After performing a pressure flow study patients with obstruction were randomized 2:1 to receive 5 mg. finasteride (81) or placebo (40) daily. A second pressure flow study was performed at month 12. At baseline and month 12 free urinary flow studies and transrectal ultrasound were performed, and International Prostate Symptom Score questionnaires were completed. Patients were treated between May 1994 and July 1996. RESULTS: Finasteride caused a significant decrease (-8.1 cm. water) in detrusor pressure at maximum flow (p <0.05 versus placebo p = 0.02), increase (+1.1 ml. per second) in maximum flow rate (p <0.05 versus placebo p = 0.02) and decrease (-22.8%) in prostate volume (p <0.05 versus placebo p <0.001). Men with prostates larger than 40 cc had greater improvement in detrusor pressure at maximum flow (between group difference -14.5 cm. water, 95% confidence interval -26.2 to -2.6, p = 0.02) and maximum flow rate (mean treatment effect +1.6 ml. per second, 95% confidence interval -0.2 to 3.0, p = 0.02) compared to those with prostates 40 cc or less (between group differences not significant). CONCLUSIONS: Finasteride treatment resulted in improvements in urodynamic parameters, which were greater in men with large prostates.
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The artificial urinary sphincter in the female: indications for use, surgical approach and results.
Female urinary incontinence is a common problem. Among the many treatment options a few patients may be suitable candidates for the artificial urinary sphincter (AUS). The indications for placement of an AUS are much more common in males: however, we review the indications, technique and potential complications of the AUS in the female population. Although few indications exist for the placement of an AUS in women, if proper patient selection is made, with strict adherence to proper surgical technique, it can be a suitable treatment option for those suffering from sphincteric incontinence.
Female↗
High-power potassium-titanyl-phosphate (KTP/532) laser vaporization prostatectomy: 24 hours later.
OBJECTIVES: To study the feasibility and immediate postoperative outcome of vaporization prostatectomy by high-power potassium-titanyl-phosphate (KTP/532) laser in 10 men with bladder outlet obstruction due to benign prostatic hyperplasia (BPH) and to evaluate their clinical and voiding outcome 24 hours postoperatively. METHODS: The KTP/532 laser at 60 W was produced by a prototype Laserscope generator and delivered through a side-deflecting fiber with a 22F continuous-flow cystoscope. Sterile water was used for irrigation. The prostatic lobes were readily vaporized to within capsular fibers. The mean lasing time was 29 +/- 8 minutes, during which a mean of 104.6 +/- 30 kJ of energy was delivered. RESULTS: The prostate volumes ranged from 22 to 60 mL (mean 38.4 +/- 9.7). None of the 10 patients had any significant blood loss or any fluid absorption. Foley catheters were removed in less than 24 hours postoperatively. All patients were satisfied with their voiding outcome. The mean peak urine flow rate increased from 8 +/- 1.3 mL/s preoperatively to 19.4 +/- 8.4 mL/s (142%, P = 0.003266) 24 hours postoperatively. Postvoid residual volumes remained essentially unchanged from their preoperative levels, as expected (P = 0.767423). One patient had urgency, but none had dysuria, hematuria, or incontinence or required recatheterization. Three patients have returned for 3-month follow-up; all 3 patients have had excellent results and are very satisfied with the outcome. CONCLUSIONS: Our very early and limited experience indicates that high-power KTP/532 laser vaporization prostatectomy is feasible and appears to be safe and effective for quickly relieving bladder outlet obstruction due to BPH. Larger randomized clinical trials to compare this technique with standard transurethral resection of the prostate and more follow-up data are needed to determine its long-term efficacy and durability.
Aged↗
Postprostatectomy urinary incontinence: a comparison of the cost of conservative versus surgical management.
OBJECTIVES: Post-radical prostatectomy stress incontinence occurs in up to 20% of patients. Postprostatectomy incontinence is initially treated with undergarments, pads, or drip collectors. Patients with persistent leakage are often treated with a transurethral bulking agent (Contigen) or placement of an artificial genitourinary sphincter (AGUS). We have compared the direct costs of each treatment at our institution over 10 years. METHODS: The Mayo Clinic estimating office provided the Medicare and non-Medicare charges for patients receiving both collagen injection (outpatient) and AGUS placement (2-day hospitalization) during August 1995. The Mayo Store provided the current price of all undergarments, pads, and drip collectors carried. Two local grocery stores provided the cost of Depends undergarments. RESULTS: The following items were the least expensive carried at the Mayo Clinic Store: Entrust undergarments, Active Style pads, and Conveen drip collectors at $0.99, $0.52, $1.05 each, respectively. The average cost of Depends undergarments was $0.52 each. The cost of wearing 5 of the least expensive undergarments or pads per day for 10 years is $9497. The average estimated Medicare and non-Medicare cost for outpatient (general anesthesia) collagen injection is $4300 and $5625, respectively. The average Medicare and non-Medicare cost for AGUS placement is $15,400 and $20,300, respectively. Factoring in our current 22.4% reoperation rate, the average per patient Medicare and non-Medicare cost for AGUS placement is $18,850 and $24,847, respectively. CONCLUSIONS: The cost of the AGUS placement compares favorably with the cost of transurethral collagen injection (under general anesthesia) in patients requiring several (more than three) collagen injection treatments or requiring the continued use of undergarments after collagen injection. Whereas the cost of transurethral collagen injection, when effective, compares favorably with conservative treatment, AGUS placement is significantly more expensive than conservative management for almost all patients except the exceedingly rare patient wearing more than 9 undergarments or pads per day. When the psychosocial benefit of urinary continence is considered, however, transurethral injection of collagen or AGUS placement often becomes the preferred treatment.
Ambulatory Surgical Procedures↗
An implantable mechanical urinary sphincter: a new nonhydraulic design concept.
OBJECTIVES: We present data concerning an artificial implantable mechanical urinary sphincter that was designed to eliminate the inherent problems of the current hydraulic artificial urinary sphincter (American Medical System [AMS] 800). Our goal was to design a sphincter that creates urethral compression similar to the AMS 800 but creates the force without the use of fluid, thereby eliminating as much as 50% of the reoperations seen with the AMS 800, which occur because of fluid-related malfunctions. METHODS: An implantable artificial mechanical sphincter consisting of a compressive coil encompassed in a polytetrafluoroethylene sheath was devised and tested in 6 live mongrel dogs to establish compressive force versus bladder pressure data, so as to provide data to create a mechanical sphincter for use in humans. RESULTS: A direct relationship between bladder leakage pressure and cable tension force was demonstrated in all 6 experimental animals, thereby creating a mathematical equation that can be used by mechanical engineers to design a mechanical sphincter for use in humans. CONCLUSIONS: This study demonstrated that a mechanical urinary sphincter can be created that will provide continence and eliminate the problems associated with the hydraulic aspect of the AMS 800. In doing so, nearly 50% of the reoperations seen with the current AMS 800 can be eliminated, thereby improving the quality of life of patients for whom an artificial urinary sphincter is indicated.
Animals↗
Total alloplastic replacement of the urinary bladder.
Bladder cancer is the second most common malignancy of the genitourinary tract. In 1992, the estimated incidence of bladder cancer in the United States was 50,000 cases. Cystectomy and urinary diversion were the preferred methods of treatment. Currently, these patients undergo various types of intestinal urinary diversion. These procedures represent a significant advancement over bilateral ureterostomies; however, many problems are associated with their use and they are among the topics discussed in this article.
Humans↗
Textural modification of processing tomatoes.
Knowledge of the textural properties of processing tomatoes is crucial to ensuing product acceptability; measurement, control, and optimization of these properties through judicious selection of varieties and control of unit operations results in products that the consumer prefers. It is important to first define the terms texture, rheology, consistency, and viscosity prior to discussing principles of their measurement. The textural properties of processing tomatoes may be measured using both sensory and objective tests, and the latter may be either destructive or nondestructive in nature. The unique anatomy of tomato fruit (peel, pericarp, columella, and locules) in part dictates the method of texture measurement. Numerous factors, including variety, maturity, genetic modification, cultural particles, and environmental conditions, processing conditions, and calcium addition affect the textural integrity of tomatoes. Textural properties of raw tomatoes and most processed tomato products are reviewed in this article.
Food Handling↗
High-power potassium titanyl phosphate laser vaporization prostatectomy.
In a search for potential therapeutic strategies for benign prostatic hyperplasia (BPH) that would be associated with less morbidity than transurethral resection of the prostate, various types of laser prostatectomy have been used. Although the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser allows performance of prostatectomy in an almost bloodless field and without absorption of irrigant, the remaining necrotic tissue causes bladder outlet obstruction and related symptoms for 5 to 7 days after treatment. In contrast, the potassium titanyl phosphate (KTP) laser has been found to vaporize tissue with minimal coagulation of the underlying structures. With use of the KTP laser, heat is concentrated into a small volume, the tissue is ablated by rapid vaporization of cellular water, and a 2-mm rim of coagulated tissue is left. After favorable results were obtained in studies of canine prostates and human cadavers, we implemented clinical use of 60-W KTP laser prostatectomy in selected patients. In 10 patients with symptomatic BPH who ranged in age from 52 to 80 years, outpatient KTP laser prostatectomy yielded significantly increased mean peak urinary flow rates (from 8.0 mL/s preoperatively to 19.4 mL/s within 24 hours after the procedure). No patient had hematuria, dysuria, or incontinence after removal of the catheter, and no patient required recatheterization. One patient, however, had urgency, and two other patients became febrile during the 24-hour observation period. Overall, KTP laser vaporization prostatectomy can provide immediate relief from obstructive symptoms of BPH and is not associated with dysuria.
Animals↗
Transurethral enzyme injection--future management of benign prostatic hyperplasia.
Although benign prostatic hyperplasia, a common condition among elderly men, has been effectively treated with transurethral resection of the prostate, this surgical procedure is associated with many well-recognized risks and complications. Because of this potential morbidity and mortality, various alternative treatment strategies for benign prostatic hyperplasia have been proposed. The use of enzyme solubilization and ablation of prostatic tissue to alleviate urinary outlet obstruction has proved effective in dogs and warrants investigation in human trials. Transurethral enzyme injection of the prostate has the potential for being a treatment modality with minimal invasiveness, limited requirements for anesthesia, and minimal associated toxicity for the management of benign prostatic hyperplasia.
Anti-Bacterial Agents↗
Mayo Clinic long-term analysis of the functional durability of the AMS 800 artificial urinary sphincter: a review of 323 cases.
PURPOSE: We determine the long-term durability of the AMS 800* artificial urinary sphincter in the correction of severe urinary incontinence, and evaluate mechanical versus nonmechanical failure and reoperation rates before (1983 to 1987) and after (1988 to present) the introduction of the narrow backing occlusive cuff design. MATERIALS AND METHODS: From January 1983 to October 1994 more than 400 patients received an AMS 800 artificial urinary sphincter placed by 1 surgeon and 323, mean age 60.4 years, met study requirements for review. Mean followup was 68.8 months (range 18 to 153). Only patients with a minimum of 18 months of followup were included in the study. Of the 313 men and 10 women in the study group sphincters were placed at the urethra in 272 and at the bladder neck in 51. All patients were followed from surgery to the date of sphincter failure. Etiology of the failures was recorded and divided into mechanical versus nonmechanical sphincters placed before and after the introduction of the narrow backing cuff. RESULTS: Overall, 58 of the 139 patients (42%) in the pre-narrow backing cuff group versus 31 of the 184 (17%) in the narrow backing cuff group required a first reoperation. Mechanical failure occurred in 29 cases (21%) with the pre-narrow backing and 14 (7.6%) with the narrow backing cuff. Nonmechanical failure developed in 24 cases (17%) with the pre-narrow backing and 17 (9%) with the narrow backing cuff. Ultimately 437 operations were required in the 323 patients, of whom 234 (72%) required no further surgical intervention at a mean followup of 68.8 months. CONCLUSIONS: Technological advances in the design and construction of the AMS 800 have dramatically decreased the reoperation and failure rates. These advances and improved surgical techniques provide an excellent long-term solution and increased continence in correctly selected patients with urinary incontinence.
Female↗
Clinical research priorities in renal cell carcinoma: renal cell carcinoma chemoprevention strategies including target populations, proposed agents, and clinical trial designs--Workgroup No. 6. Union Internationale Contre le Cancer (UICC) and the American Joint Committee on Cancer (AJCC).
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Biomarkers, Tumor↗
Use of the artificial urinary sphincter in men and women.
There are numerous therapeutic options for treating incontinence. Implantation of an artificial genitourinary sphincter is an excellent choice in cases of incontinence due to sphincteric dysfunction. In this article we report the Mayo Clinic data from several large series and compare these data to other recent reviews. In addition, we review current recommendations regarding patient selection and evaluation. There were 458 patients who underwent implantation of an artificial sphincter, including 417 men and 41 women. The overall continence rate was 88.2%, the reoperation rate was 23.1%, and the mechanical reliability was 88%. Satisfaction rates were greater than 90%. We conclude that artificial sphincter implantation is safe, reliable and very effective in treating incontinence due to sphincteric dysfunction in properly selected patients.
Female↗