Importance of Reversible Attachment in Predicting E. Coli Transport in Saturated Aquifers From Column Experiments.

Drinking water wells indiscriminatingly placed adjacent to fecal contaminated surface water represents a significant but difficult to quantify health risk. Here we seek to understand mechanisms that limit the contamination extent by scaling up bacterial transport results from the laboratory to the field in a well constrained setting. Three pulses of E. coli originating during the early monsoon from a freshly excavated pond receiving latrine effluent in Bangladesh were monitored in 6 wells and modeled with a two-dimensional (2-D) flow and transport model conditioned with measured hydraulic heads. The modeling was performed assuming three different modes of interaction of E. coli with aquifer sands: 1) irreversible attachment only (best-fit ki=7.6 day-1); 2) reversible attachment only (ka=10.5 and kd=0.2 day-1); and 3) a combination of reversible and irreversible modes of attachment (ka=60, kd=7.6, ki=5.2 day-1). Only the third approach adequately reproduced the observed temporal and spatial distribution of E. coli, including a 4-log10 lateral removal distance of ∼9 m. In saturated column experiments, carried out using aquifer sand from the field site, a combination of reversible and irreversible attachment was also required to reproduce the observed breakthrough curves and E. coli retention profiles within the laboratory columns. Applying the laboratory-measured kinetic parameters to the 2-D calibrated flow model of the field site underestimates the observed 4-log10 lateral removal distance by less than a factor of two. This is promising for predicting field scale transport from laboratory experiments.

Effect of anesthesia on voiding function after tension-free vaginal tape procedure.

OBJECTIVE: To determine whether the mode of anesthesia used during the tension-free vaginal tape procedure affects postoperative voiding function. METHODS: A retrospective cohort study was performed using cases in which tension-free vaginal tape placement was the sole procedure performed. Of the 173 cases reviewed, we were able to use the data from 163. Hierarchal linear regression was used to identify independent predictors of our dependent variable: days to complete voiding. In the first block, established predictors of postoperative voiding dysfunction were entered into the model. In the second block, potential confounders of the relationship between anesthesia type and days to complete voiding identified during univariate analysis (P <.15) were entered into the model. In the third block, anesthesia type was entered into the model to determine whether it added any unique variance after controlling for previously established predictors of postoperative voiding dysfunction. RESULTS: The mean days to complete voiding was similar in our local or regional anesthesia (n = 90) and general anesthesia groups (n = 73) (2.3 [0-21] versus 2.3 [0-14], P =.95). Our final regression model (F = 2.74, P =.011) included age, prior pelvic organ prolapse surgery, and preoperative urge symptoms and explained 22.2% of the variance in days to complete voiding. Anesthesia type did not add any predictive improvement after controlling for these variables. CONCLUSION: General anesthesia, and therefore lack of a cough-stress test, does not increase the chance of postoperative voiding dysfunction associated with tension-free vaginal tape.

The safety of reusing injectable collagen: a multicenter microbiological study.

We have previously reported pilot data regarding the safety of saving partially used syringes of a glutaraldehyde cross-linked collagen for use in subsequent treatment sessions with the same individual. That single institution study involved 56 partially used syringes cultured for aerobic bacteria. Only one weakly positive culture was detected among these 56 samples, which prompted us to carry out this expanded study involving multiple centers and different injection techniques. Samples were collected from four centers. Following periurethral injection in an office setting, 166 partially used syringes of glutaraldehyde cross-linked collagen were refrigerated for between 1 and 104 weeks (average 58). Material from all 166 syringes was then cultured qualitatively and quantitatively for both aerobic and anaerobic organisms. Collagen from one syringe grew >100,000 colonies of Escherichia coli. All other cultures were negative. In the pilot study, one culture of 56 syringes was weakly positive for coagulase-negative staphylococcus. When the results from both studies were considered together, only two of 222 partially used syringes (0.9%) were contaminated. The background risk of local infection associated with periurethral collagen injection is approximately 0.29%. Using the statistical equation 'number needed to harm', we found that a clinician would have to reuse 111 syringes at a saving of $34,965 before he or she would cause a single local injection by so doing. Therefore, we feel that it may be cost-effective and safe to reinject material from a partially used syringe of glutaraldehyde cross-linked collagen during a subsequent treatment session on an individual.

Protective effect of suburethral slings on postoperative cystocele recurrence after reconstructive pelvic operation.

OBJECTIVE: The purpose of this study was to evaluate the independent effect of suburethral sling placement on the risk of cystocele recurrence after pelvic reconstructive operation. STUDY DESIGN: One hundred forty-eight women with cystoceles to or beyond the hymenal ring underwent pelvic reconstructive operation, with or without incontinence procedures, and were evaluated at 12 and 52 weeks after operation with a standardized pelvic examination. Rates of recurrent prolapse, at all sites, were statistically compared between subjects with and without suburethral slings. A multiple regression analysis was used to determine the independent effect of sling placement on the risk of recurrent cystoceles. RESULTS: Suburethral sling placement was associated with a 54.8% reduction in the mean rate of postoperative cystocele recurrence (P =.004). This protective effect was observed as early as 12 weeks and remained significant at 1-year follow up (42% vs 19%). A markedly reduced risk of cystocele recurrence was observed when women with sling procedures were compared with all other women, with those women who underwent other incontinence operations, and even with those women who had undergone prolapse repair with no incontinence procedure. The protective effect of the sling procedure remained highly significant (odds ratio, 0.29; P =.0003), even after controlling for potentially confounding variables in a multiple logistic regression model. CONCLUSION: Suburethral sling procedures appear to significantly reduce the risk of cystocele recurrence after pelvic reconstructive operation, in contrast with the effect of retropubic urethropexy and needle suspensions. These findings should be considered when the surgical treatment of stress incontinence that accompanies pelvic organ prolapse is being planned.

Anterior or posterior sacrospinous vaginal vault suspension: long-term anatomic and functional evaluation.

OBJECTIVE: To compare vaginal anatomy and sexual function after the conventional posterior and anterior sacrospinous vault suspension. METHODS: A retrospective repeated measures cohort study included all 168 consecutive sacrospinous vault suspension procedures between July 1990 and February 1997. The posterior suspension (n = 92) used a posterior vaginal incision and pararectal dissection. Anterior suspension (n = 76) involved an anterior rather than posterior vaginal incision, retropubic perforation, and dissection of a paravaginal-paravesical rather than pararectal space to accommodate the vaginal vault. Two polytetrafluoroethylene (00) sutures anchored the anterior vaginal cuff (for the anterior sacrospinous suspension) or the posterior vaginal cuff (for the posterior sacrospinous suspension) to the ligament. Postoperative evaluation included an examination using the pelvic organ prolapse quantitative system, assessment of vaginal width and axis, and symptom questionnaire. RESULTS: Total vaginal length and apical suspension were slightly greater after the anterior suspension, and recurrent anterior vaginal relaxation was less likely. No differences were found in maximal dilator size or apical narrowing between the two groups. New onset dyspareunia was reported by two subjects in the anterior vault suspension group, and two in the posterior vault suspension group. Three of these four cases of de novo dyspareunia were attributable to either severe atrophy or recurrent prolapse, and none to vaginal narrowing or shortening. CONCLUSION: After anterior sacrospinous vault suspension, vaginal length and apical suspension were slightly increased, and recurrent anterior vaginal prolapse decreased compared with the posterior sacrospinous suspension technique. Upper vaginal caliber and sexual function appear well preserved using either technique.

Comparison of microtransducer and fiberoptic catheters for urodynamic studies.

OBJECTIVE: To assess the validity and reproducibility of a fiberoptic transducer urodynamic catheter for urethral closure pressure profiles and leak point pressure determination, using a microtransducer catheter as the standard. METHODS: Ninety women without significant pelvic organ prolapse underwent urodynamic evaluations with both fiberoptic and microtransducer catheters. Maximal urethral closure pressures and "leak point pressures" were repeatedly measured by the two catheters and statistically compared. The order of catheter use was randomized. RESULTS: Significantly lower mean maximal urethral closure pressures were recorded by the fiberoptic system than by the microtransducer system (28.9 cmH(2)O +/- 17.3 versus 43.2 cmH(2)O +/- 24.9, P <.001). The fiberoptic catheter predicted microtransducer values for maximum urethral closure pressure only within a range of 27 cmH(2)O. Mean "leak point pressure" recorded by the fiberoptic catheters (66.9 cmH(2)O +/- 2.9) was not significantly different than that recorded by the microtransducer catheters (66.4 cmH(2)O +/- 2.9, P =.97). CONCLUSION: There is a significant difference between maximum urethral closure pressure values recorded by the microtransducer and fiberoptic catheter systems. No significant difference was found between the two systems in measurement of Valsalva "leak point pressure."

Prospective randomized trial of polyglactin 910 mesh to prevent recurrence of cystoceles and rectoceles.

OBJECTIVE: Our aim was to evaluate the efficacy of polyglactin 910 mesh in preventing recurrent cystoceles and rectoceles. STUDY DESIGN: In a prospective, randomized, controlled trial, patients undergoing vaginal reconstructive surgery with cystoceles to the hymenal ring and beyond were randomly selected to undergo anterior and posterior colporrhaphy with or without polyglactin 910 mesh reinforcement. Results were evaluated preoperatively and at 2, 6, 12, and 52 weeks postoperatively. RESULTS: A total of 161 women were randomly selected for this study. One woman was excluded at the time of surgery, and 17 women were lost to follow-up. Eighty women received mesh, and 80 did not. Both groups were found to be equivalent with respect to age, parity, concomitant surgery, and menopausal and hormone replacement status. Preoperatively 49 women had a central cystocele to the hymenal ring and 111 women had cystoceles beyond the introitus; 91 women had a rectocele to the mid-vaginal plane, 31 to the hymenal ring, and 22 beyond the introitus. After 1 year, 30 (43%) of 70 subjects without mesh and 18 (25%) of 73 subjects with mesh had recurrent cystoceles beyond the mid-vaginal plane (P =.02). Eight women without mesh and 2 women with mesh had recurrent cystoceles to the hymenal ring (P =.04). No recurrent cystoceles beyond the hymenal ring occurred in either group. Multivariate logistic regression analysis showed concurrent slings to be associated with significantly fewer recurrent cystoceles (odds ratio, 0.32; P =.005), whereas the presence of mesh remained significantly predictive of fewer cystocele recurrences in this analysis. Thirteen recurrent rectoceles were noted 1 year postoperatively, with no differences between groups. CONCLUSION: Polyglactin 910 mesh was found to be useful in the prevention of recurrent cystoceles.

Urinary incontinence in women: evaluation and management.

Because the prevalence of urinary incontinence increases with age, a working knowledge of the diagnosis and treatment of the various types of urinary incontinence is fundamental to the care of women. As the population of the United States ages, primary care physicians can expect to see an increasing number of patients with urinary incontinence. By obtaining a careful medical history and performing a comprehensive physical examination, the primary care physician can initiate successful treatment for the majority of patients without the need for invasive testing. This article offers a comprehensive approach to the evaluation and management of urinary incontinence in women.

Is it safe to reuse a syringe of glutaraldehyde cross-linked collagen? A microbiological study.

PURPOSE: We evaluated the safety of saving partially used syringes of glutaraldehyde cross-linked collagen for subsequent treatment sessions in an individual. MATERIALS AND METHODS: After periurethral injection in an office setting 56 partially used syringes of glutaraldehyde cross-linked collagen were stored in a refrigerator for 1 to 61 weeks (mean 15). Collagen from all 56 syringes was then cultured qualitatively using a broth medium at 35C and semiquantitatively using a chocolate agar plate at 22 to 30C for 5 days each. RESULTS: A qualitative broth culture was positive for coagulase negative staphylococcus but the results of semiquantitative chocolate agar culture of material from the same syringe were negative. All cultures of the other 55 syringes were negative. CONCLUSIONS: The positive culture most likely resulted from contamination during periurethral injection or the culturing process. Minimal contamination from and the great potential cost savings of reusing glutaraldehyde cross-linked collagen for subsequent treatments in an individual indicate the need for an expanded study involving multiple centers.

A prospective randomized study comparing modified Burch retropubic urethropexy and suburethral sling for treatment of genuine stress incontinence with low-pressure urethra.

OBJECTIVE: The aim of this study was to compare a modified Burch procedure with a suburethral sling for the treatment of stress incontinence complicated by a low-pressure urethra. STUDY DESIGN: Thirty-six women with stress incontinence, low-pressure urethra, and urethral hypermobility (straining cotton swab angle >/=30 degrees ) were randomly assigned to undergo either a modified Burch procedure (n = 19) or a suburethral sling (n = 17). Objective and subjective cure rates at 3 months after the operation were the primary outcome measures. Comparisons of group means were performed with the Student t test for independent groups, and proportions were compared with the Fisher exact test. RESULTS: After the operation the 2 groups had statistically similar cure rates and voiding function. Urethral closure pressure, pressure transmission ratios, and maximum detrusor pressure during voiding were significantly higher in the sling group. CONCLUSION: At 3 months there were no clinically significant differences between the groups treated with suburethral sling and modified Burch procedures.

Centrifuge modeling of air sparging - a study of air flow through saturated porous media.

The success of air sparging as a remedial technology for treatment of contaminated aquifers is well documented. However, there is no consensus, to date, on the mechanisms that control the flow of injected air through the saturated ground. Currently, only qualitative results from laboratory experiments are available to predict the zone of influence of a sparging well. Given that the patterns of air flow through the soil will ultimately determine the efficiency of an air sparging treatment, it is important to quantify how sparged air travels through a saturated porous medium. The main objective of this research is to develop a model that describes air transport through saturated porous media. This paper presents results from an ongoing study that employs centrifuge modeling to reproduce in situ air sparging conditions. Centrifuge testing is an experimental technique that allows reduced-scale duplication, in the laboratory, of the stresses and pressure distributions encountered in the field. In situ conditions are critical in the development of actual air flow patterns. Experiments are being conducted in a transparent porous medium consisting of crushed borosilicate glass submerged in fluids of matching indices of refraction. Air is observed as it flows through the porous medium at varying gravitational accelerations. Recorded images of experiments allow the determination of flow patterns, breakthrough velocities, and plume shapes as a function of g-level and injection pressure. Results show that air flow patterns vary from fingering, at low g-levels, to pulsing at higher accelerations. Grain and pore size distribution of the porous medium do not exclusively control air flow characteristics. Injector geometry has a definite effect on breakthrough velocities and air plume shapes. Experiments have been conducted to compare the velocity of air flow through the saturated porous medium to that of air in pure liquids. Results show that the velocity of air through the medium is lower than that in the pure fluid, as expected. At high g-levels however, plume breakthrough velocities are proportional to the velocity of the air in the pure fluid.

Validity and cost-effectiveness of antisperm antibody testing before in vitro fertilization.

OBJECTIVE: To determine the usefulness of and cost-effectiveness of antisperm antibody testing in the prediction of poor fertilization rates in couples undergoing IVF. DESIGN: Retrospective cohort study. SETTING: A hospital-based reproductive endocrinology and infertility practice. PATIENT(S): Male partners of 251 couples undergoing IVF between 1992 and 1997. MAIN OUTCOME MEASURE(S): Fertilization rates in couples undergoing conventional IVF. RESULT(S): One hundred nineteen couples were evaluated for antisperm antibodies; fertilization rates were similar in those couples whose husbands were and were not tested (64% versus 68%). Antisperm antibodies were detected in 16 men. Four (25%) of the 16 couples whose husbands had antisperm antibodies fertilized < or = 50% of oocytes, compared with 31 (30%) of the 103 couples whose husbands did not have these antibodies. Overall, 21 couples (8.4%) experienced complete fertilization failure. In a program that included antisperm antibody testing for selected couples and intracytoplasmic sperm injection (ICSI) for those who tested positive, it would cost $11,735 to prevent a fertilization failure (assuming ICSI were 100% effective), whereas it would cost $9,250 to perform ICSI in a second IVF cycle for those who initially failed. CONCLUSION(S): In this practice setting, antisperm antibody testing has low sensitivity in predicting low or no fertilization and does not appear to be cost-effective when selectively ordered as part of an IVF workup.