Risk factors and outcome of contamination in patients on peritoneal dialysis--a single-center experience of 15 years.

OBJECTIVE: Contamination is an important risk factor for peritoneal dialysis (PD)-related peritonitis. The present study outlines the clinical characteristics and outcomes of PD patients experiencing touch contamination. METHODS: We reviewed the case records of PD patients from 1995 to 2010. Patients who experienced contamination of their PD system were identified and stratified into "dry" and "wet" contamination groups. Risk factors, microbiology, and clinical outcomes were compared. RESULTS: Of 548 episodes of touch contamination, 246 involved dry contamination, and 302, wet contamination. After contamination, 17 episodes of peritonitis (3.1%) developed; all episodes occurred in the wet contamination group (p < 0.001). The incidence of peritonitis after wet contamination was 5.63%. Prophylactic antibiotics significantly reduced the risk of peritonitis (1 of 182 episodes, p < 0.001). Half the patients experiencing peritonitis had either culture-negative or staphylococcal episodes, and most of those episodes responded to intraperitoneal antibiotics. In 2 patients, peritonitis was attributable to Pseudomonas, and in 3, to Acinetobacter. In these latter patients, outcomes were less favorable, with catheter removal being required in 4 of the 5 episodes. CONCLUSIONS: The overall rate of peritonitis was low after contamination. Wet contamination was associated with a much higher risk of peritonitis. Prophylactic antibiotics after wet contamination were effective in preventing peritonitis.

Validation of a new yeast-based reporter assay consisting of human estrogen receptors alpha/beta and coactivator SRC-1: application for detection of estrogenic activity in environmental samples.

Endocrine disruptors are exogenous substances that act like hormones in the endocrine system and disrupt the physiologic function of endogenous hormones. In the present study, we established reporter yeast strains (Saccharomyces cerevisiae) expressing human estrogen receptors, ERalpha or ERbeta. These strains contain a reporter plasmid carrying an estrogen responsive element (ERE) upstream of the beta-galactosidase gene, and a plasmid expressing a steroid receptor coactivator, SRC-1e. Using these reporter strains, we demonstrated dose-dependent estrogenic activities of different categories of ligands, a natural hormone, 17beta-estradiol (E2); a synthetic drug, diethylstilbestrol (DES); phytoestrogens, genistein, daizein and emodin; and an environmental endocrine disrupter, bisphenol A. EC(50) values of E2 for ERalpha and ERbeta are 5.31 x 10(-10) and 5.85 x 10(-10) M, respectively. We also demonstrated that these yeasts were applicable for measuring estrogenic activities of environmental water samples. Most downstream sites of a river showed similar activity in both ERalpha and ERbeta assays. These yeast strains are useful and convenient for detecting and comparing the estrogenic ligand activities of environmental samples in response to ERalpha and ERbeta.

Construction of a reporter yeast strain to detect estrogen receptor signaling through aryl hydrocarbon receptor activation.

The activation mechanism of estrogen receptor (ER) signaling by association with the aryl hydrocarbon receptor (AhR) was elucidated recently (Ohtake, et al., Nature 2003, 423, 545). In the present study, we established a reporter yeast strain to evaluate this ER signaling by association with the activated AhR. This yeast strain expresses human ER and AhR, and has a reporter plasmid with estrogen response elements. With this yeast strain we assayed ER activation by various AhR ligands, i.e., 2,3,7,8-tetrachlorodibenzo-p-dioxin, benzo[a]pyrene, 3-methylcholanthrene, beta-naphthoflavone, and indirubin. All these ligands induced ER activation dose-dependently and their EC50 values were 60, 180, 130, 26, and 0.5 nM, respectively. Then, we measured the activity in water collected at 5 localities in the Ishizu River system in Japan. The activities of water samples ranged from 4.8 pmol/L (1.3 ng/L) to 52 pmol/L (14 ng/ L) (17beta-estradiol (E2) equivalent). These values were higher than those measured with the yeast for ER activation through direct ligand binding to ER. The direct ER ligand binding activities of the water samples ranged from 2.5 to 5.3 pmol/L (E2 equivalent). We also measured AhR activation of the water samples using a reporter yeast for AhR ligand activity. The activities ranged from 102 to 472 pmol/L (beta-naphthoflavone equivalent). These results indicate that the water samples contain substances that bind to AhR, and these substances contribute to ER signaling through AhR activation in the yeast reporter strain. This yeast reporter strain should be a useful tool to evaluate direct and indirect ER activation by environmental samples.

Preparing patients for peritoneal dialysis.

When told of their need for dialysis, patients often cannot accept it and are fearful toward dialysis. Pre-dialysis counseling programs help patients to face dialysis, to make the right choice of dialysis modality, and to prepare themselves for life on dialysis. Clear explanations of peritoneal dialysis (PD) help patients choosing PD. Patients should be referred to pre-dialysis programs at least 4 - 6 months before commencement of dialysis or when their glomerular filtration rate is around 15 mL/min/1.73 m(2). The pre-dialysis program is best conducted by experienced staff such as renal nurses and multidisciplinary staff including nephrologists, dietitians, physiotherapists, psychologists, social workers, or even dialysis patient representatives depending on availability. The program should be designed according to the culture, settings, staff availability, and patient load in individual hospitals. Pre-dialysis home visits may be needed in some cases to assess suitability and prepare the home for PD.

A prospective randomized study on three different peritoneal dialysis catheters.

OBJECTIVE: We compared outcomes for catheters with different configurations: conventional straight, swan-neck straight tip, and swan-neck curled tip. DESIGN: The study was conducted as a prospective randomized controlled trial in the continuous ambulatory peritoneal dialysis (CAPD) unit of a university center. PATIENTS AND METHODS: We randomized 93 new regular CAPD patients without prior peritoneal dialysis (PD) catheter insertion to receive a conventional straight, double-cuffed catheter (CS), a swan-neck straight catheter (SNC), or a swan-neck curled tip catheter (SNC) in 2:1:1 ratio. RESULTS: The exit-site infection (ESI) rate was slightly lower with swan-neck catheters as compared with straight catheters, but the difference was not statistically significant. The peritonitis rate and overall catheter survival were similar. In Staphylococcus aureus nasal non carriers as compared with carriers, ESI-free catheter survival was significantly better with swan-neck catheters (p = 0.0302 and p = 0.82 respectively). As compared with SC catheters, SNC catheters had a significantly higher migration rate (p = 0.022). CONCLUSIONS: Swan-neck catheters were associated with a slightly better ESI rate, but SNC catheters are not routinely recommended because of a high migration rate. The SNS catheter is therefore recommended as the first-line catheter of choice, particularly in populations with a low rate of S. aureus nasal carriage.

Screening by trained nurses for peripheral vascular disease in continuous ambulatory peritoneal dialysis patients with and without diabetes.

OBJECTIVE: We studied the effectiveness of a screening program for peripheral vascular disease (PVD) carried out by trained renal nurses in patients with and without diabetes on continuous ambulatory peritoneal dialysis (CAPD). PATIENTS AND METHODS: We recruited 30 stable diabetic and 30 stable non diabetic CAPD patients into this cross-sectional study. Trained renal nurses measured the patients' ankle-to-brachial systolic pressure index (ABI) using a Doppler ultrasound machine and their foot vibration perception (VPT) using a biothesiometer, and administered a questionnaire on foot symptoms. An ABI < 1.0 was regarded as abnormal and suggestive of the presence of PVD. An ABI < 0.7 or > 1.3 was regarded as severely abnormal. Findings for VPT were classified as normal or abnormal. Patients were then followed for 1 year for any overt development of clinical PVD, leg complications, and other vascular complications and for clinical outcome. RESULTS: The mean age of the patients was 63 +/- 9 years, and the ratio of men to women was 1:1.3. An abnormal ABI was seen in 22 patients (37%). The questionnaire detected clinical PVD symptoms in 3 patients. Abnormal ABI and VPT findings were more frequent in diabetic patients. After 12 months of follow-up, patients with an abnormal ABI (and particularly those with a severely abnormal ABI) were more likely to develop leg complications and any type of cardiovascular disease than were patients with a normal ABI. Foot vibration perception had no predictive value on subsequent development of leg complications. When risk factors including age, ABI, and VPT were analyzed by logistic regression, only ABI was a significant independent predictor of subsequent lower-limb vascular complications [odds ratio (OR): 21.0; 95% confidence interval (CI): 2.35 to 187.0; p = 0.00064]. The OR for moderately abnormal ABI was 13.0 (95% CI: 1.015 to 166.3); for severely abnormal ABI, it was 27.4 (95% CI: 2.35 to 187.0, p = 0.0045). CONCLUSIONS: Measurement of ABI by Doppler ultrasound is a useful and effective screening test for PVD in CAPD patients. In this study, VPT was not shown to be predicative of future leg complications, indicating that peripheral neuropathy plays a less important role in the development of such complications. Our results proved that trained renal nurses can play an active role in detecting foot problems in renal patients by ABI measurement.