Fidgetin-like 2 depletion enhances cell migration by regulating GEF-H1, RhoA, and FAK

The microtubule (MT) cytoskeleton and its dynamics play an important role in cell migration. Depletion of the microtubule-severing enzyme Fidgetin-like 2 (FL2), a regulator of MT dynamics at the leading edge of migrating cells, leads to faster and more efficient cell migration. Here we examine how siRNA knockdown of FL2 increases cell motility. Förster resonance energy transfer biosensor studies shows that FL2 knockdown decreases activation of the p21 Rho GTPase, RhoA, and its activator GEF-H1. Immunofluorescence studies reveal that GEF-H1 is sequestered by the increased MT density resulting from FL2 depletion. Activation of the Rho GTPase, Rac1, however, does not change after FL2 knockdown. Furthermore, FL2 depletion leads to an increase in focal adhesion kinase activation at the leading edge, as shown by immunofluorescence studies, but no change in actin dynamics, as shown by fluorescence recovery after photobleaching. We believe these results expand our understanding of the role of MT dynamics in cell migration and offer new insights into RhoA and Rac1 regulation.

Correlates of late-onset antipsychotic treatment resistance

Introduction

There is emerging evidence of heterogeneity within treatment-resistance schizophrenia (TRS), with some people not responding to antipsychotic treatment from illness onset and a smaller group becoming treatment-resistant after an initial response period. It has been suggested that these groups have different aetiologies. Few studies have investigated socio-demographic and clinical differences between early and late onset of TRS.

Objectives

This study aims to investigate socio-demographic and clinical correlates of late-onset of TRS.

Methods

Using data from the electronic health records of the South London and Maudsley, we identified a cohort of people with TRS. Regression analyses were conducted to identify correlates of the length of treatment to TRS. Analysed predictors include gender, age, ethnicity, positive symptoms severity, problems with activities of daily living, psychiatric comorbidities, involuntary hospitalisation and treatment with long-acting injectable antipsychotics.

Results

We observed a continuum of the length of treatment until TRS presentation. Having severe hallucinations and delusions at treatment start was associated shorter duration of treatment until the presentation of TRS.

Conclusions

Our findings do not support a clear cut categorisation between early and late TRS, based on length of treatment until treatment resistance onset. More severe positive symptoms predict earlier onset of treatment resistance.

Disclosure

DFdF, GKS, EF and IR have received research funding from Janssen and H. Lundbeck A/S. RDH and HS have received research funding from Roche, Pfizer, Janssen and Lundbeck. SES is employed on a grant held by Cardiff University from Takeda Pharmaceutical Comp

198 Immediate Post-Operative PDE5i Therapy Improves Early Erectile Function Outcomes after Robot-Assisted Radical Prostatectomy (RARP)

Aim

To assess whether the timing of post-operative Phosphodiesterase Inhibitor (PDE5i) therapy after Robot Assisted Radical Prostatectomy (RARP) is associated with a change in early erectile function, continence, or safety outcomes.

Method

Data was prospectively collected from a single surgeon in one tertiary centre and retrospectively evaluated. 158 patients were treated with PDE5i therapy post RARP over a two-year period.

Results

There were no significant differences in pre-operative characteristics between the therapy groups. Patients that had bilateral nerve sparing had a mean drop in Erectile Function (EF) score by 5.4 compared to 8.8 in the unilateral group. Additionally, 34.9% of bilateral nerve sparing patients returned to baseline compared to 12.1% of unilateral. Drop in EF scores and percentage return to baseline for unilateral nerve sparing was respectively 9 and 11.1% of immediate (day 1-2), 7 and 14.8% of early (day 3-14) and 9.7 and 9.5% of late (day >14) therapy (p = 0.9 and p = 0.6). For bilateral nerve sparing this was respectively 3.5 and 42.9% immediate therapy, 5.5 and 35.5% early therapy and 7.3 and 25% late therapy (p = 0.017 and p = 0.045). Pad free and social continence was achieved in 54% and 37% of those receiving immediate therapy, 60% and 33% for early therapy and 26% and 54% for late therapy. There were no differences in compliance, complication, or readmission outcomes.

Conclusions

Immediate PDE5i therapy should be considered in patients following nerve sparing RARP in order to maximise functional outcomes, especially in those undergoing bilateral nerve spare.

31 Immediate Post-Operative Phosphodiesterase-5 Inhibitors (PDE5i) Therapy Improves Early Erectile Function Outcomes After Robot Assisted Radical Prostatectomy (RARP)

Introduction

To assess whether the timing of post-RARP PDE5i therapy affects early erectile function, continence, or safety outcomes.

Method

Data from 158 patients treated with PDE5is post-RARP was prospectively collected over two years from a single surgeon at one tertiary centre and retrospectively evaluated. Therapy was started: immediately (day 1-2) in 29%, early (day 3-14) in 37% and late (after day 14) post-op in 34%. EPIC-26 Erectile Function (EF) scores were collected pre-op and post-op after a median 43-day follow-up interval.

Results

Drop in EF scores and percentage return to baseline post unilateral nerve sparing (UNS) compared to bilateral nerve sparing (BNS) RARP was respectively 9 and 11.1% versus 3.5 and 42.9% of immediate therapy, 7 and 14.8% versus 5.5 and 35.5% of early and 9.7 and 9.5% versus 7.3 and 25% of late. Pad free and social continence was achieved in 54% and 37% of those receiving immediate therapy, 60% and 33% for early and 26% and 54% for late.

Conclusions

Immediate post RARP PDE5i therapy may protect EF and should be considered clinically, with more benefits for BNS than UNS patients. Immediate or early, rather than late, PDE5i therapy improved early continence in BNS patients.

Investigating Tongue Strength and Endurance in Children Aged 6 to 11 Years

Objective measures of tongue strength and endurance are used to assess lingual weakness and fatigue, and may have significant clinical value for dysphagia management. Recent studies investigating age and gender effects on tongue strength in children are limited by small sample sizes. The current study investigated age and gender effects on tongue strength with a larger sample size, and collected preliminary normative data for a paediatric population. This study also investigated the reliability of tongue endurance measures in children using a modified method, which has not previously been investigated. Using a cross-sectional design, this study examined tongue strength and endurance in 119 children aged 6 to 11 years, with no history of speech sound disorders, oro-motor deficits, dysphagia or cognitive impairment. Measures were collected using the Iowa Oral Performance Instrument. Children participated in two sessions, 45 min and 10 min in duration. Tongue strength was found to significantly increase with age (p < 0.001), while no gender effects were found. Modified tongue endurance measures involved using only one measure of maximal tongue strength to set parameters for tongue endurance scores. Despite this modification, data did not reach acceptable test-retest reliability, ICC = 0.68, p < 0.001; however, reliability improved from previous studies. These findings provide normative data for tongue strength, as a basis to compare individuals, and highlights the need for more reliable protocols for measuring tongue endurance. Normative data was collected from city-dwelling Australian children.

The Development of Technology for Effective Respiratory-Gated Irradiation Using an Image-Guided Small Animal Irradiator

The development of image-guided small animal irradiators represents a significant improvement over standard irradiators by enabling preclinical studies to mimic radiotherapy in humans. The ability to deliver tightly collimated targeted beams, in conjunction with gantry or animal couch rotation, has the potential to maximize tumor dose while sparing normal tissues. However, the current commercial platforms do not incorporate respiratory gating, which is required for accurate and precise targeting in organs subject to respiration related motions that may be up to the order of 5 mm in mice. Therefore, a new treatment head assembly for the Xstrahl Small Animal Radiation Research Platform (SARRP) has been designed. This includes a fast X-ray shutter subsystem, a motorized beam hardening filter assembly, an integrated transmission ionization chamber to monitor beam delivery, a kinematically positioned removable beam collimator and a targeting laser exiting the center of the beam collimator. The X-ray shutter not only minimizes timing errors but also allows beam gating during imaging and treatment, with irradiation only taking place during the breathing cycle when tissue movement is minimal. The breathing related movement is monitored by measuring, using a synchronous detector/lock-in amplifier that processes diffuse reflectance light from a modulated light source. After thresholding of the resulting signal, delays are added around the inhalation/exhalation phases, enabling the "no movement" period to be isolated and to open the X-ray shutter. Irradiation can either be performed for a predetermined time of X-ray exposure, or through integration of a current from the transmission monitor ionization chamber (corrected locally for air density variations). The ability to successfully deliver respiratory-gated X-ray irradiations has been demonstrated by comparing movies obtained using planar X-ray imaging with and without respiratory gating, in addition to comparing dose profiles observed from a collimated beam on EBT3 radiochromic film mounted on the animal's chest. Altogether, the development of respiratory-gated irradiation facilitates improved dose delivery during animal movement and constitutes an important new tool for preclinical radiation studies. This approach is particularly well suited for irradiation of orthotopic tumors or other targets within the chest and abdomen where breathing related movement is significant.

Analysis of multigenerational families with thoracic aortic aneurysms and dissections due to TGFBR1 or TGFBR2 mutations

BACKGROUND

Mutations in the transforming growth factor beta receptor type I and II genes (TGFBR1 and TGFBR2) cause Loeys-Dietz syndrome (LDS), characterised by thoracic aortic aneurysms and dissections (TAAD), aneurysms and dissections of other arteries, craniosynostosis, cleft palate/bifid uvula, hypertelorism, congenital heart defects, arterial tortuosity, and mental retardation. TGFBR2 mutations can also cause TAAD in the absence of features of LDS in large multigenerational families, yet only sporadic LDS cases or parent-child pairs with TGFBR1 mutations have been reported to date.

METHODS

The authors identified TGFBR1 missense mutations in multigenerational families with TAAD by DNA sequencing. Clinical features of affected individuals were assessed and compared with clinical features of previously described TGFBR2 families.

RESULTS

Statistical analyses of the clinical features of the TGFBR1 cohort (n = 30) were compared with clinical features of TGFBR2 cohort (n = 77). Significant differences were identified in clinical presentation and survival based on gender in TGFBR1 families but not in TGFBR2 families. In families with TGFBR1 mutations, men died younger than women based on Kaplan-Meier survival curves. In addition, men presented with TAAD and women often presented with dissections and aneurysms of arteries other than the ascending thoracic aorta. The data also suggest that individuals with TGFBR2 mutations are more likely to dissect at aortic diameters <5.0 cm than individuals with TGFBR1 mutations.

CONCLUSION

This study is the first to demonstrate clinical differences between patients with TGFBR1 and TGFBR2 mutations. These differences are important for the clinical management and outcome of vascular diseases in these patients.

Vegetation composition of roadside verges in Scotland: the effects of nitrogen deposition, disturbance and management

Vehicular emissions of NO(x) and NH(3) result in elevated concentrations of nitrogen at roadside verges. To determine the extent that vehicular nitrogen emissions, disturbance and management affect the vegetation composition of road verges, a survey of 92 verges in Scotland was carried out with sites stratified by background nitrogen deposition and road type. NO(x) and NH(3) concentrations were monitored at 15 key sites for a year, and showed a decreasing gradient with increasing distance from the road. Ellenberg fertility indices of the vegetation communities also showed a general decrease with increasing distance from the road, but there was no straightforward correlation with NO(x) and NH(3) air concentrations between sites. Cover of bare ground, ruderal species and salt-tolerant species were highest at the verge edge. The proximity of the verge to traffic is important both in terms of NO(x) and NH(3) gradients, but also for deposited salt, grit and physical disturbance.

Going to the doctors: the views of mothers of children with recurrent abdominal pain

OBJECTIVES

to explore how mothers of children with recurrent abdominal pain view seeking medical help on behalf of their children.

DESIGN

qualitative interview study.

SETTING

paediatric clinics and schools.

PARTICIPANTS

purposive sample of 28 mothers of children with recurrent abdominal pain.

MAIN OUTCOME MEASURES

Beliefs concerning recurrent abdominal pain, the respective roles of doctors and mothers and the nature and quality of interactions with doctors.

RESULTS

Mothers of children with recurrent abdominal pain reported shaping the way they discussed the child's problem with doctors according to their beliefs about their own roles and the beliefs they perceived doctors to hold about recurrent abdominal pain. Where they were seeking help in managing the pain, they often felt undermined and threatened and responded to this by stressing the physical aspects of the child's presentation.

CONCLUSIONS

Doctors may need to acknowledge actively mothers' competence in order to establish a therapeutic alliance.

Social and sexual risk factors for bacterial vaginosis

BACKGROUND

A number of sexual and social risk factors for bacterial vaginosis (BV) have been identified. However, many previous studies have used small numbers of patients, or highly selected or convenience samples, or poorly defined populations. This study aims to clarify potential sexual and non-sexual risk factors for BV.

METHODS

Women attending the Sydney Sexual Health Centre with BV, between March 1991 and July 1999, were included. Controls were randomly selected women without BV. Information on the demographics, clinical findings, and sexual and non-sexual risk behaviours were extracted from the clinic database and analysed using SPSS and SAS. A logistic regression model was used to establish which associations with BV persisted.

RESULTS

890 women with BV and 890 controls were studied. Factors that were independently associated with BV were > or =3 male sexual partners in the past 12 months (OR = 1.60, 95% CI: 1.19 to 2.04), at least one female sexual partner in the past 12 months (OR = 2.1, p = 0.003), a past pregnancy (OR = 1.5, p<0.0006), and smoking. In contrast, women with BV were significantly less likely to have used hormonal contraception (OR = 0.60, 95% CI: 0.51 to 0.81) or to have used condoms consistently (OR = 0.5, 95% CI: 0.31 to 0.71) than controls.

CONCLUSION

Our findings may be important for planning a preventive strategy for BV by discouraging smoking and increasing condom use and hormonal contraception among women.

Diagnosing PID--getting the balance right

The objective of the study was to determine the clinical manifestations and diagnostic criteria used to diagnose presumptive pelvic inflammatory disease (PID) at the Sydney Sexual Health Centre (SSHC). The study was a retrospective, case-note review of all women diagnosed with presumptive PID between April 1991 and December 1997. Seven hundred and thirteen women were included. The commonest recorded symptoms were vaginal discharge (68%), lower abdominal pain (65%) and dyspareunia (57%), while adnexal tenderness (83%), cervical motion tenderness (75%) and cervicitis (56%) were the most frequently recorded examination findings. Sixty-two per cent were prescribed doxycycline and metronidazole. The recording of signs and symptoms in women with presumptive PID was poor and only 22% met the current Centers for Disease Control (CDC) diagnostic criteria. It is likely that PID is over diagnosed in this group of women. This may lead to under diagnosis of other conditions causing pelvic pain and may be detrimental to reproductive health.

Polyelectrolyte vectors for gene delivery: influence of cationic polymer on biophysical properties of complexes formed with DNA

Cationic polymer/DNA complexes are widely used for gene delivery, although the influence of the cationic polymer on the biophysical properties of the resulting complex is poorly understood. Here, several series of cationic polymers have been used to evaluate the influence of structural parameters on properties of DNA complexes. Parameters studied included the length of side chain, charge type (primary versus tertiary and quaternary), polymer molecular weight, and charge spacing along the polymer backbone. Cationic polymers with short side chains (such as polyvinylamine) formed small complexes, resistant to destabilization by polyanions, with low surface charge, limited transfection activity, and efficient intranuclear transcription. Conversely, cationic polymers with long side chains (e.g., poly[methacryloyl-Gly-Gly-NH-(CH(2))(6)-NH(2))] showed inefficient complex formation, high positive surface charge, and better transfection activity. The effects of molecular weight varied between polymers, for example, low molecular weight poly(L-lysine) produced relatively small complexes, whereas low molecular weight poly[2-(trimethylammonio)ethyl methacrylate chloride] produced large aggregates. Polymers containing quaternary ammonium groups showed efficient complex formation but poor transfection. Finally, spreading charges widely on the polymer structure inhibited their ability to condense DNA. In summary, to achieve small, stable complexes, the use of cationic polymers with short side chains bearing primary amino groups is suggested.

Reduced movement of median nerve in carpal tunnel during wrist flexion in patients with non-specific arm pain

Magnetic resonance scans on patients with non-specific arm pain (repetitive strain injury) show reduced median-nerve movement in the carpal tunnel, suggesting that this common condition may involve nerve entrapment.

Dobutamine-atropine stress echocardiography for reversible dysfunction during the first week after acute myocardial infarction: limitations and determinants of accuracy

OBJECTIVES

We sought to compare the accuracy of biphasic and ischemic responses and sustained improvement for reversible dysfunction and to identify causes of false negative and false positive findings.

BACKGROUND

Previous studies have shown that low dose dobutamine echocardiography was accurate for detecting reversible dysfunction after acute myocardial infarction (MI) but did not determine whether accuracy was improved by peak dose findings or influenced by the test interval or clinical or angiographic factors.

METHODS

Dobutamine-atropine stress echocardiography (DASE) (baseline, low dose [5 and 10 microg/kg body weight per min] and peak dose) and coronary angiography were performed in 115 patients 2 to 7 days after MI (test interval). Segmental wall thickening was analyzed according to the 16-segment model. Sustained improvement and biphasic and ischemic responses included improved wall thickening at low and peak doses, improved wall thickening at the low dose with worsening at peak dose and no change in wall thickening at the low dose with worsening at peak dose, respectively. Follow-up echocardiography was performed at 4 to 8 weeks, and reversible dysfunction was defined as improved wall thickening.

RESULTS

Wall thickening improved at follow-up in 305 (44%) of 688 dysfunctional segments. The test interval was 2 days in 16 patients, 3 days in 24, 4 days in 24, 5 days in 12, 6 days in 16 and 7 days in 23. No change at low and peak doses accurately predicted fixed dysfunction (318 [88%] of 360 segments), especially in akinetic and dyskinetic segments (276 [91%] of 303), irrespective of the test interval or clinical and angiographic factors. Ischemic segmental responses also predicted fixed dysfunction (63% [12 of 19 patients]), especially in medically treated compared with revascularized patients (100% [8 of 8] vs. 36% [4 of 11], p = 0.013). Both biphasic responses and sustained improvement (77% [179 of 231 segments] vs. 87% [84 of 97], p = 0.082) were highly predictive of reversible dysfunction, especially in akinetic segments, irrespective of the test interval or clinical and angiographic factors. The only limitation was reduced accuracy (77% [177 of 222 segments], p < 0.001) due to false positive results (16%) in hypokinetic segments.

CONCLUSIONS

No change and ischemic responses during DASE were specific for fixed dysfunction. Improved wall thickening at the low dose, irrespective of changes at peak dose, was highly predictive of reversible dysfunction. Accuracy was only limited by false positive results in hypokinetic segments and not by the test interval or clinical or angiographic factors.

Low dose dobutamine echocardiography is more predictive of reversible dysfunction after acute myocardial infarction than resting single photon emission computed tomographic thallium-201 scintigraphy

To directly compare dobutamine echocardiography and resting single photon emission computed tomographic (SPECT) thallium-201 (Tl-201) scintigraphy for the detection of reversible dysfunction, 64 patients underwent dobutomine echocardiography (baseline, low dose 5 and 10 mg/kg/min, and peak dose), rest Tl-201 scintigraphy (3 mCi - 15 minute and 3- to 4-hour SPECT imaging), and coronary angiography during the first week after acute myocardial infarction. Follow-up echocardiography was performed 4 to 8 weeks after discharge. Wall thickening improved at follow-up in 52% (207 of 399) of the dysfunctional segments. By receiver operating characteristic analysis, biphasic responses and sustained improvement during dobutamine echocardiography were more accurate (p < 0.01) than Tl-201 uptake by SPECT scintigraphy for reversible dysfunction. The greater accuracy of dobutamine echocardiography resulted from higher accuracy in akinetic segments, Q wave infarction, and multivessel coronary artery disease. In conclusion, dobutamine echocardiography was more accurate than resting SPECT Tl-201 scintigraphy for reversible dysfunction after acute myocardial infarction.

Enterogastric bile reflux during technetium-99m-sestamibi cardiac imaging

Enterogastric bile reflux (EGBR), a risk factor for both gastritis and esophagitis, is a potentially treatable noncoronary cause for chest pain.

METHODS

To investigate the frequency of EGBR during different 99mTc-sestamibi cardiac imaging, 1405 consecutive 99mTc-sestamibi SPECT myocardial perfusion studies were reviewed.

RESULTS

One hundred sixteen of the 1405 patient studies (8.3%) showed EGBR with roughly equal numbers of patients having marked (43 patients), moderate (38 patients) or minimal (35 patients) intensity of abnormal gastric activity. Two examinations showed gastroesophageal reflux of activity. EGBR was less frequent with treadmill stress testing (5.5% patients) than with pharmacologic stress testing using either dipyridamole (11% of patients) or dobutamine (9.2% of patients) (p > 0.005). EGBR also was more frequent in patients over 40 yr of age. Finally, the prevalence of upper gastrointestinal symptoms and the frequency of established upper gastrointestinal diagnoses correlated strongly with the presence and intensity of EGBR.

CONCLUSION

Clarification of the full clinical significance of EGBR during 99mTc-sestamibi cardiac imaging is a topic for future research. Nonetheless, the imaging finding of EGBR may, in fact, identify a potentially treatable noncoronary cause for chest pain.

Addressing the health needs of teenagers with a drop-in clinic

This article describes an initiative to assess and meet the particular health needs of teenagers in Northumberland. The author describes the reasons for the drop-in clinic's inception and the range of services which are offered to what was perceived as a neglected group.

Maternal serum screening and routine 18-week ultrasound in the detection of all chromosomal abnormalities

Over a 15-month period, maternal serum screening (alpha fetoprotein, oestriol, chorionic gonadotrophin) and ultrasound were evaluated in the detection of all chromosomal abnormalities. Of the 981 screened, there were 8 chromosomally abnormal pregnancies. Six of these were considered to be at increased risk on serum screening, all of which were detected. Of the remaining 2, one was detected by ultrasound and the other resulted in a liveborn baby with trisomy 21. The positive and negative predictive values for serum screening for all chromosomal abnormalities was 7.8% and 99.9% respectively. The sensitivity and specificity was 87.5% and 91.5% respectively. Serum screening is useful in the detection of many chromosomal abnormalities, not just Down syndrome. The combination of maternal serum screening and ultrasound has a high negative predictive value and is valuable in providing reassurance of no underlying chromosomal abnormality. With a positive predictive value of 7.8% a chromosomal abnormality will be found once in every 13 amniocenteses performed.

Influence of cardiac failure on atrial natriuretic peptide responses in patients undergoing vascular surgery

Sixteen patients presenting for abdominal aortic surgery were divided into two groups according to whether or not there was a history and clinical evidence of chronic heart failure (CHF). Atrial natriuretic peptide (ANP) and catecholamines were measured during a preoperative exercise test and then with induction of anaesthesia and surgery. Patients in the CHF group (n = 8) had a much-reduced cardiac output (CO) rise in response to exercise compared to the control group (13% vs. 75%, P less than 0.05). This difference was due to the absence of a stroke volume increase in the CHF group. Induction of anaesthesia resulted in a greater fall in mean arterial pressure in the CHF group prior to the start of surgery, due to a greater fall in CO. Plasma ANP levels were higher in the CHF group at rest and at each exercise stage (P less than 0.05). ANP levels were not altered by induction of anaesthesia or intubation, but increased with the start of surgery in the CHF group (P less than 0.05). Increases in plasma catecholamine levels in response to exercise and to surgery were similar in the two groups. Changes in endogenous ANP may be important in counteracting the undesirable effects of vasoconstrictor hormones during physical exercise or surgical stress.

Nosocomial fungemia in neonates associated with intravascular pressure-monitoring devices

In the period from January, 1982, to March, 1983, eight infants in the neonatal intensive care unit at one hospital had blood cultures positive for Candida parapsilosis; six cases had occurred after December, 1982. Epidemiologic investigation included a case-control study comparing the 8 cases with 29 birth weight-matched controls. Logistic regression analysis indicated that the model that best fit the observed data included the following risk factors for fungemia: duration of umbilical artery catheterization; duration of receipt of parenteral nutrition; and estimated gestational age. Parenteral nutrition therapy was often administered through the umbilical artery catheters, which were also used for monitoring arterial pressure; transducer domes thus contained parenteral nutrition fluid. Transducers were usually disinfected with alcohol. Laboratory investigation showed that the heads of 6 of 11 in-use blood pressure transducers and 1 of 4 transducers in storage after cleaning were culture-positive for C. parapsilosis. After control measures were instituted no further cases occurred.

Evaluation of H2O2 prophylaxis of bacteriuria in patients with long-term indwelling Foley catheters: a randomized controlled study

Since the long-term catheterized patient is at significant risk of urinary tract infection, and the catheter drainage bags of these patients are at significant risk of becoming reservoirs for nosocomial pathogens, we carried out a randomized, controlled study to determine the efficacy of intermittent drainage bag instillation of hydrogen peroxide (H2O2) in patients requiring indwelling Foley catheters for 5 days or more. Herein we report the effects of this technique on the rates of catheter and bag bacteriuria, the duration to positive culture, the temporal relationships observed, and the spectrum of organisms recovered. Bag source bacteriuria was found with the same frequency in both control and H2O2 groups. H2O2 did reduce contamination of the drainage bag but did not reduce catheter-associated bacteriuria or frequency of symptomatic urinary tract infection. Furthermore, H2O2 did not reduce the frequency of bag contamination with most of the common nosocomial urinary pathogens.