Synthesis of Shape-Controllable Anisotropic Microparticles and "Walnut-like" Microparticles via Emulsion Interfacial Polymerization.

Anisotropic microparticles have plenty of applications for their asymmetric structure and precisely modified surface. In our research, the uniform anisotropic microparticles with benzyl chloride group were synthesized successfully via emulsion interfacial polymerization. By varying the degree of cross-linking and the concentration of slightly hydrophilic monomer 4-vinyl benzyl chloride (VBC), several types of microparticles with different concavities and different shapes of microparticles (hemisphere, bowl-like, egg-like, etc.) were obtained. Nanoporous microparticles with a walnut-like heterostructure were achieved with modified hydrophilic seeds with the same strategy. The potential applications of shape-controllable fluorescent microparticles and surface modification of microparticles by thiol-click reaction were explored. The modified microparticles achieved in this study are very useful in labeling, tracing, protein separation, and other biomedical fields.

Cancer Incidence and Mortality in Chronic Dialysis Population: A Multicenter Cohort Study.

BACKGROUND: Different studies in the past have shown that the risk of cancer development is increased in chronic dialysis patients. However, data concerning the cancer risk in Asian dialysis patients was scarce. More importantly, there was lack of information about the cancer-specific mortality in dialysis patients. METHODS: A multicenter retrospective cohort study of 6,254 patients who started either chronic peritoneal dialysis or hemodialysis between 1994 and 2014 in 4 renal units in Hong Kong. Patterns of cancer incidence and mortality in our dialysis patients were compared with those of the general population using standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) respectively. RESULTS: With 14,887 person-years of follow-up, 220 cancers were recorded. The SIR of all cancers was 1.44 (95% CI 1.26-1.65). A trend of an increased SIR was observed in young patients and within the first year of dialysis. Colorectum was the most common site of cancer (20%) while kidney cancer carried the highest risk (SIR 12.28, 95% CI 8.44-17.08). The SMR of all cancers was 0.91 (95% CI 0.72-1.13) and only kidney cancer had higher cancer mortality risk (SMR 4.92, 95% CI 1.80-10.70). SMR was highest in young patients and then decreased with age. CONCLUSIONS: The incidence of cancers in our chronic dialysis patients was elevated. Our findings of substantially increased risks in young patients, particularly in relation to kidney cancer, suggest that we can adopt a more individualized approach to cancer screening in chronic dialysis patients.

Impact of a low-glucose peritoneal dialysis regimen on fibrosis and inflammation biomarkers.

BACKGROUND: The impact of a low-glucose peritoneal dialysis (PD) regimen on biomarkers of peritoneal inflammation, fibrosis and membrane integrity remains to be investigated. METHODS: In a randomized, prospective study, 80 incident PD patients received either a low-glucose regimen comprising Physioneal (P), Extraneal (E) and Nutrineal (N) (Baxter Healthcare Corporation, Deerfield, IL, USA) (PEN group), or Dianeal (control group) for 12 months, after which both groups continued with Dianeal dialysis for 6 months. Serum and dialysate levels of vascular endothelial growth factor (VEGF), decorin, hepatocyte growth factor (HGF), interleukin-6 (IL-6), macrophage migration inhibitory factor (MIF), hyaluronan (HA), adiponectin, soluble-intracellular adhesion molecule (s-ICAM), vascular cell adhesion molecule-1 (VCAM-1) and P-selectin, and dialysate cancer antigen 125 (CA125), were measured after 12 and 18 months. This paper focuses on results after 12 months, when patients in the PEN group changed to glucose-based PD fluid (PDF). RESULTS: At the end of 12 months, effluent dialysate levels of CA125, decorin, HGF, IL-6, adiponectin and adhesion molecules were significantly higher in the PEN group compared to controls, but all decreased after patients switched to glucose-based PDF. Macrophage migration inhibitory factor level was lower in the PEN group but increased after changing to glucose-based PDF and was similar to controls at 18 months. Serum adiponectin level was higher in the PEN group at 12 months, but was similar in the 2 groups at 18 months. Body weight, residual renal function, ultrafiltration volume and total Kt/V did not differ between both groups. Dialysate-to-plasma creatinine ratio at 4 h was higher in the PEN group at 12 months and remained so after switching to glucose-based PDF. CONCLUSION: Changes in the biomarkers suggest that the PEN PD regimen may be associated with better preservation of peritoneal membrane integrity and reduced systemic vascular endothelial injury.

Prevalence of and associations with reduced exercise capacity in peritoneal dialysis patients.

BACKGROUND: Exercise capacity is reduced in patients with end-stage renal disease on maintenance home peritoneal dialysis therapy, although the potential mechanisms and clinical implications remain unclear. STUDY DESIGN: Cross-sectional study. SETTING & PARTICIPANTS: 95 ambulatory prevalent and incident peritoneal dialysis patients in a well-established renal dialysis center (mean age, 58.26 ± 12.6 [SD] years; 63% men; mean duration of peritoneal dialysis therapy, 3.2 ± 4.1 years). PREDICTOR: Estimated volume status using spectral bioelectrical impedance, echocardiography-derived hemodynamic parameters. OUTCOME: Exercise capacity measured as peak oxygen consumption using symptom-limiting treadmill exercise testing. RESULTS: Exercise capacity was reduced in 96% of patients and severely reduced in 65%. Extracellular to intracellular fluid volume ratio showed the strongest correlation with reduced exercise capacity (R = -0.63; P < 0.001) and was superior to age, pulmonary capillary wedge pressure (E:E' ratio), lean tissue mass index, and hemoglobin and albumin levels in predicting exercise intolerance. LIMITATIONS: Relatively small sample size and echocardiogram that was performed only at rest. CONCLUSIONS: There was a strong relationship between body extracellular to intracellular fluid volume ratio and exercise capacity in peritoneal dialysis patients. These findings provide new evidence for a connection between fluid distribution, muscle mass, and exercise capacity. Therapeutic strategies targeting fluid status and muscle mass may improve the exercise capacity of patients on peritoneal dialysis therapy.

A combination of biocompatible peritoneal dialysis solutions and residual renal function, peritoneal transport, and inflammation markers: a randomized clinical trial.

BACKGROUND: The benefits of biocompatible peritoneal dialysis (PD) fluids, particularly for residual renal function (RRF), are controversial. Moreover, the clinical effects of a PD regimen consisting of different biocompatible PD fluids have not been fully established. STUDY DESIGN: Prospective, randomized, controlled, open-label study. SETTING & PARTICIPANTS: Patients with end-stage kidney disease newly started on continuous ambulatory PD therapy (N = 150). INTERVENTION: A 12-month intervention with 3 biocompatible PD fluids (a neutral-pH, low glucose degradation product, 1.5% glucose solution; a solution with 1.1% amino acid; and a fluid with 7.5% icodextrin) or conventional PD fluid. OUTCOMES: The primary outcome was change in RRF and daily urine volume. Secondary outcomes were peritoneal transport and inflammation markers. MEASUREMENTS: RRF, daily urine volume, serum and dialysate cytokine levels. RESULTS: RRF(3.24 ± 1.98 vs 2.88 ± 2.43 mL/min/1.73 m(2); P = 0.9) and rate of decline in RRF (-0.76 ± 1.77 vs -0.91 ± 1.92 mL/min/1.73 m(2) per year; P = 0.6) did not differ between the biocompatible- and conventional-PD-fluid groups. However, patients using the biocompatible PD fluids had better preservation of daily urine volume (959 ± 515 vs 798 ± 615 mL/d in the conventional group, P = 0.02 by comparison of difference in overall change by repeated-measures analysis of variance). Their dialysate-plasma creatinine ratio at 4 hours was higher at 12 months (0.78 ± 0.13 vs 0.68 ± 0.12; P = 0.01 for comparison of the difference in overall change by repeated-measures analysis of variance). They also had significantly higher serum levels of adiponectin and overnight spent dialysate levels of cancer antigen 125, adiponectin, and interleukin 6 (IL-6). No differences between the 2 groups were observed for serum C-reactive protein and IL-6 levels. LIMITATIONS: Unblinded, relatively short follow-up; no formal sample-size calculations. CONCLUSIONS: Use of a combination of 3 biocompatible PD fluids for 12 months compared with conventional PD fluid did not affect RRF, but was associated with better preservation of daily urine volume. The biocompatible PD fluids also lead to changes in small-solute transport and an increase in dialysate cancer antigen 125, IL-6, adiponectin, and systemic adiponectin levels, but have no effect on systemic inflammatory response. The clinical significance of these changes, while of great interest, remains to be determined by further studies.

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.

Clinical course and outcomes of single-organism Enterococcus peritonitis in peritoneal dialysis patients.

BACKGROUND AND OBJECTIVES: Enterococci are part of the normal flora of the gastrointestinal tract. They can cause enteric peritonitis, which is a serious complication of peritoneal dialysis (PD). However, the clinical course and outcome of PD-related Enterococcus peritonitis remains unclear. METHODS: We reviewed all Enterococcus peritonitis episodes occurring in our dialysis unit from 1995 to 2009. RESULTS: During the study period, 1421 episodes of peritonitis were recorded. Of 29 episodes (2.0%) that were attributable to single-organism Enterococcus, 12 episodes were caused by E. faecalis; 9, by E. faecium; and the remaining 8, by other Enterococcus species. The overall rate of ampicillin resistance was 41.4%. Recent use of antibiotics was associated with the development of ampicillin-resistant Enterococcus (ARE) peritonitis (hazard ratio: 12.53; p = 0.04). The primary response rate of Enterococcus peritonitis was significantly higher than that of Escherichia coli peritonitis (89.7% vs. 69.9%, p = 0.038), but the primary response rate was not significantly lower for ARE peritonitis than for ampicillin-susceptible Enterococcus (ASE) peritonitis (83.3% vs. 94.1%, p = 0.553). However, significantly more patients with ARE had received vancomycin (83.3% vs. 23.5%, p = 0.003), with a longer mean duration of vancomycin treatment (11.8 ± 6.9 days vs. 3.7 ± 6.8 days, p = 0.005). CONCLUSIONS: Recent use of antibiotics was a risk factor for the development of ARE peritonitis. Outcomes in ASE and ARE peritonitis were similar, but vancomycin was required during treatment for ARE peritonitis, in turn possibly predisposing the patients to infections caused by vancomycin-resistant organisms.

A prospective randomized study comparing tenckhoff catheters inserted using the triple incision method with standard swan neck catheters.

BACKGROUND AND OBJECTIVE: The downward directed exit of the swan neck catheter may decrease the risk of exit-site infection (ESI). The percentage of migrations of the swan neck catheter seems to be less than the conventional Tenckhoff catheter and the swan neck catheter is more expensive and cannot be manipulated by guidewire technique if tip migration occurs. In this study, the conventional Tenckhoff catheter was used. The straight tunnel was converted to an arcuate one using the triple incision method, resulting in a downward directed exit. The arcuate tunnel was created by passing the catheter through an additional incision located between the paramedian incision and the exit site. We compared the infective and mechanical complications of the Tenckhoff catheter with a downward exit, implanted using the triple incision method, with the swan neck catheter. PATIENTS AND METHODS: 101 new peritoneal dialysis patients were prospectively randomized to receive either the Tenckhoff catheter with a downward exit, implanted using the triple incision method, or the swan neck catheter. Each patient was followed up for 24 months. 50 patients were in the triple incision method group (TIMG) and 51 were in the swan neck catheter group (SNCG). RESULTS: Over a mean period of 18.9 +/- 8.0 months of follow-up, ESI occurred in 35 patients (70%) in TIMG and 37 patients (72.5%) in SNCG (p = 0.83). The ESI rates were 0.71 and 1.0 episodes/catheter-year in TIMG and SNCG respectively (p = 0.21). The peritonitis rates were similar in the 2 groups (0.64 episodes/year in TIMG and 0.68 episodes/year in SNCG, p = 0.47). More patients in TIMG had tip migration [15 patients (30%) in TIMG vs 10 patients (19.6%) in SNCG] but the difference was not statistically significant. Repositioning of the catheter by guidewire manipulation was successful in patients in TIMG but not in SNCG. Overall catheter survival at 12 and 24 months was 95% and 83% in TIMG and 93% and 79% in SNCG respectively (p = 0.72). CONCLUSION: By using the conventional Tenckhoff catheter with a downward exit created using the triple incision method, high catheter survival rates with infective and mechanical complication rates similar to those of the swan neck catheter can be achieved. The triple incision method has the additional advantages of lower cost and the catheter can be manipulated by guidewire technique if tip migration occurs.

Cefazolin plus netilmicin versus cefazolin plus ceftazidime for treating CAPD peritonitis: effect on residual renal function.

UNLABELLED: BACKGROUND. The International Society for Peritoneal Dialysis (ISPD) treatment guidelines for continuous ambulatory peritoneal dialysis (CAPD) peritonitis 2000 recommended the use of cefazolin plus ceftazidime as the initial empirical therapy in patients with residual renal function (RRF). However, this treatment regimen has not been compared with the conventional regimen of cefazolin plus netilmicin in prospective, randomized controlled trials. METHODS: Stable CAPD patients who developed clinical evidence of peritonitis were randomized to receive intraperitoneal (i.p.) cefazolin plus netilmicin or cefazolin plus ceftazidime once daily in the long dwell for 14 days. For patients with RRF (>1 mL/minute) before entry into the study (N= 50), RRF and 24-hour urine volume were measured at days 1, 14, and 42 after commencement of i.p. antibiotic treatment. RESULTS: One hundred and two patients were recruited into the study. The primary cure rates of i.p. cefazolin plus netilmicin and cefazolin plus ceftazidime were 66.7% and 64.7%, respectively. The overall cure rate for the 2 treatment regimens was 82.3% for both. Seven patients (14%) from each treatment group required removal of the dialysis catheters due to treatment failure. Relapse of peritonitis occurred in 2 patients (4%) in both treatment groups. Thirty-six patients with RRF at baseline achieved primary cure of their peritonitis by the assigned antibiotics. In this subgroup of patients, their RRF and daily urine volume showed significant reduction at day 14 and returned to near baseline values at day 42. The degree of reduction in RRF and urine volume did not differ significantly between the patients treated with cefazolin plus netilmicin and cefazolin plus ceftazidime. CONCLUSION: Intraperitoneal cefazolin plus netilmicin and cefazolin plus ceftazidime have similar efficacy as empirical treatment for CAPD peritonitis. In CAPD patients with RRF, significant but reversible reduction in RRF and 24-hour urine volume could occur after an episode of peritonitis, despite successful treatment by i.p. antibiotics. The effect of i.p. cefazolin plus netilmicin, or i.p. cefazolin plus ceftazidime on RRF in CAPD patients with peritonitis does not appear to be different. Our findings do not support the routine use of cefazolin and ceftazidime as the empirical treatment for CAPD peritonitis.

Effect of Kt/V on survival and clinical outcome in CAPD patients in a randomized prospective study.

BACKGROUND: There has been a lack of randomized control study on the effect of Kt/V on patient outcome. This interventional study was designed to examine the effect of Kt/V on continuous ambulatory peritoneal dialysis (CAPD) patients' clinical outcome and nutritional status in a randomized prospective manner. METHOD: A total of 320 new CAPD patients with baseline renal Kt/V <1.0 were recruited from six centers in Hong Kong and were randomized into three Kt/V targets: group A, 1.5 to 1.7; group B, 1.7 to 2.0; and group C,>2.0. Kt/V and nutritional status were assessed every 6 months and dialysis prescription adjusted accordingly. Nutritional assessment included serum albumin and composite nutritional index (CNI). Patients were allowed to withdraw at the discretion of their physicians or themselves. RESULTS: Total Kt/V were significantly different between groups (P = 0.000) and the difference was contributed by peritoneal Kt/V only. The overall 2-year patient survival was 84.9%. There was no statistical difference in patient survival among the three groups (2-year survival in group A, 87.3%; group B, 86.1%; and group C, 81.5%). However, there were more patients withdrawn by physicians in group A (group A, 16; group B, 7; and group C, 6; P = 0.023). Total Kt/V or Kt did not significantly affect survival after adjustment to age and diabetes. There was no difference in serum albumin, CNI scores, and hospitalization rate, but there were more patients in group A requiring erythropoietin (EPO) treatment after 1 year. CONCLUSION: Patients with total Kt/V maintained below 1.7 had significantly more clinical problems and severe anemia but there was no difference in outcome demonstrated for patients with Kt/V maintained above 2.0 and between 1.7 and 2.0. We recommended that the minimal target of total Kt/V should be above 1.7.

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.

Factors associated with sleep disorders in Chinese patients on continuous ambulatory peritoneal dialysis.

OBJECTIVE: This study aimed at identifying factors that are associated with sleep disorders in Chinese patients on continuous ambulatory peritoneal dialysis (CAPD). STUDY DESIGN: Questionnaire survey. SETTING: Renal dialysis unit of a tertiary-care hospital. PATIENTS: 179 Chinese patients on CAPD. MAIN OUTCOME MEASURES: The quantity and quality of sleep were compared between CAPD patients with and without self-reported sleep disorders. Demographic variables, personality traits, behavioral factors, somatic symptoms, and clinical parameters were correlated with the presence of sleep disorders. RESULTS: The mean age of the patients was 61 +/- 12 years and the male-to-female ratio was 1:1.3. The mean duration of CAPD was 47 +/- 42 months. 110 patients (61%) had self-reported sleep disorders. Among patients with self-reported sleep disorders, difficulty falling asleep was the most frequent complaint (74.5%), followed by frequent awakening (68%) and early morning waking (68%). The mean duration of sleep among these patients was 4.6 +/- 2.2 hours, versus 7.3 +/- 1.4 hours in patients without self- reported sleep disorders. Three personality traits (anxiety, worry, and sadness) and two somatic symptoms (bone pain and arthralgia) were the factors significantly associated with sleep disorders. Patients with sleep disorders also more frequently reported certain symptoms suggestive of sleep apnea. Demographic variables, behavioral factors (e.g., caffeine or alcohol intake), and clinical parameters (e.g., adequacy of dialysis, body mass index, hemoglobin, albumin, parathyroid hormone levels) did not differ between patients with and without sleep disorders. CONCLUSIONS: Sleep disorders are prevalent among Chinese CAPD patients. Personality traits (anxiety, worry, and sadness) and somatic symptoms (bone pain and arthralgia) were the factors significantly associated with sleep disorders in this patient population. Behavioral factors, demographic variables, and clinical parameters did not appear to predict sleep disorders. Further studies evaluating the impact of various psychological factors on sleep disorders among CAPD patients are warranted.