Haemodialysis access profile in failed kidney transplant patients: Analysis of data from the Catalan Renal Registry (1998-2016)

BACKGROUND

Data about vascular access (VA) use in failed kidney transplant (KT) patients returning to haemodialysis (HD) are limited. We analysed the VA profile of these patients, the factors associated with the likelihood of HD re-initiation through fistula (AVF) and the effect of VA in use at the time of KT on kidney graft (KTx) outcome.

METHOD

Data from the Catalan Registry on failed KT patients restarting HD and incident HD patients with native kidney failure were examined over an 18-year period.

RESULTS

The VA profile of 675 failed KT patients at HD re-initiation compared with that before KT and with 16,731 incident patients starting HD was (%): AVF 79.3 versus 88.6 and 46.2 (p = 0.001 and p < 0.001), graft AVG 4.4 versus 2.6 and 1.1 (p = 0.08 and p < 0.001), tunnelled catheter TCC 12.4 versus 5.5 and 18.0 (p = 0.001 and p < 0.001) and non-tunnelled catheter 3.9 versus 3.3 and 34.7 (p = 0.56 and p < 0.001). The likelihood of HD re-initiation by AVF was significantly lower in patients with cardiovascular disease, KT duration >5 years, dialysed through AVG or TCC before KT, and females. The analysis of Kaplan-Meier curves showed a greater KTx survival in patients dialysed through arteriovenous access than in patients using catheter just before KT (λ2 = 5.59, p = 0.0181, log-rank test). Cox regression analysis showed that patients on HD through arteriovenous access at the time of KT had lower probability of KTx loss compared to those with catheter (hazard ratio 0.71, 95% CI 0.55-0.90, p = 0.005).

CONCLUSIONS

The VA profile of failed KT patients returning to HD and incident patients starting HD was different. Compared to before KT, the proportion of failed KT patients restarting HD with AVF decreased significantly at the expense of TCC. Patients on HD through arteriovenous access at the time of KT showed greater KTx survival compared with those using catheter.

Effect of kidney transplantation activity on arteriovenous fistula use in prevalent haemodialysis patients: A registry-based study

BACKGROUND

Kidney transplantation (KT) is considered to be the best kidney replacement therapy (KRT) option for most end-stage kidney disease (ESKD) patients. Arteriovenous fistula (AVF) is considered to be the best vascular access (VA) for most haemodialysis (HD) patients. In this study, we investigated the effect of KT activity on AVF use in prevalent HD patients. The probability of receiving a kidney graft (KTx) over time, depending on the first VA used to start the HD program, was also evaluated.

METHODS

Data from the Catalan Registry of prevalent patients on KRT by either KT or HD were examined over a 20-year period (1997-2017).

RESULTS

The percentage of prevalent ESKD patients with a functioning KTx increased from 40.5% in 1997 to 57.0% in 2017 and, conversely, the percentage of AVF utilisation in HD patients decreased from 86.0% to 63.2% during the same period (for both comparisons, p < 0.001). This inverse relationship was also demonstrated in other countries and regions worldwide by performing a simple linear regression analysis (R2 = 0.4974, p = 0.002). The probability of prevalent patients dialysed through an AVF in Catalonia was independently associated with the percentage of functioning KTx among KRT population, after adjusting by age, gender, primary kidney disease, time on KRT, cardiovascular disease and type of HD Unit. Incident patients starting HD through an AVF had a significantly higher probability of receiving a KTx over time in comparison to patients who initiated HD through a catheter (hazard ratio 1.68 [95% confidence interval: 1.41-2.00], p < 0.001).

CONCLUSIONS

In addition to some demographical and clinical characteristics of patients and type of HD Unit, KT activity can be a determining factor in AVF use in prevalent HD patients. Starting an HD programme through an AVF is independently associated with a greater probability of receiving a KTx as compared to starting HD through a catheter.

Changes in vascular access profile for pediatric hemodialysis patients over time: A registry-based study from Catalonia

BACKGROUND

The criteria for vascular access (VA) selection in pediatric hemodialysis (HD) population has changed over time until the current patient-centered approach using the individualized Life-Plan. We analyzed the type of VA used by incident and prevalent end-stage kidney disease (ESKD) pediatric patients (pts) treated with HD in Catalonia.

METHOD

Data from the Catalan Renal Registry of ESKD pts under 18 years of age undergoing kidney replacement therapy (KRT) were examined for a 22-year period (1997-2018).

RESULTS

ESKD children starting KRT through HD decreased progressively from 55.6% (1997-2001) to 38.2% (2012-2018) and, conversely, there was an increase in pts starting KRT by preemptive kidney transplantation (KT) from 28.9% to 42.6% between the same periods (for both comparisons, p = 0.007). Most ESKD pts started HD by fistula (AVF) from 1997 to 2001 (56.5%) but this percentage decreased over time and no AVFs were used to start HD in children from 2012 to 2018. Likewise, the percentage of children starting HD by tunneled catheter increased progressively from 8.7% to 72.2% between the same periods (for both comparisons, p < 0.001). Regarding prevalent ESKD pts, children on HD decreased from 34.9% in 1997 to 4.7% in 2018 and, conversely, pts with a functioning kidney graft increased from 62.8% to 92.4% during the same periods (for both comparisons, p < 0.001). There was a progressive decrease in the percentage of children dialyzed by AVF from 100% in 1997 to 0% in 2018 (p < 0.001). The KT rate increased from 5.4 per million population (pmp) in 1997 to 17.1 pmp in 2018 (p = 0.007). The median time on HD prior to the first KT progressively decreased to 6.6 months (2014-2018).

CONCLUSION

The high KT rate was a determining factor in choosing the VA type in the incident and prevalent pediatric population treated with HD in Catalonia.

Final Stage of Chronic Kidney Disease with Conservative Kidney Management or Renal Replacement Therapy: A Primary-Care Population Study

BACKGROUND

Studies focus on the incidence and risk factors (RFs) associated with reaching the final stage of chronic kidney disease (CKD-G5) and receiving kidney replacement therapy (KRT). Analysis of those related to reaching CKD-G5 while receiving conservative kidney management (CKM) has been neglected.

METHODS

Retrospective cohort study analysing electronic health records of individuals aged ≥ 50 with eGFR < 60 mL/min/m². Cumulative incidence rates of CKD-G5, with and without KRT, were calculated. Multinomial regression models determined odds ratios (ORs) for CKD-G5 progression with KRT, CKM, or death.

RESULTS

Among 332,164 patients, the cumulative incidence of CKD-G5 was 2.79 cases per 100 person-years. The rates were 1.92 for CKD-G5 with KRT and 0.87 for CKD-G5 with CKM. Low eGFR and albuminuria were the primary RFs. Male gender and uncontrolled blood pressure had a greater impact on KRT (OR = 2.63 CI, 1.63) than on CKD-G5 with CKM (OR = 1.45 CI, 1.31). Increasing age and rurality reduced the probability of KRT but increased the probability of CKD-G5 with CKM. Higher incomes decreased the likelihood of developing CKD-G5 with and without KRT (OR = 0.49 CI).

CONCLUSION

One-third of CKD-G5 cases receive CKM. Those are typically older, female, rural residents with lower incomes and with lesser proteinuria or cardiovascular RF. The likelihood of receiving KRT is influenced by location and socioeconomic disparities.

Data quality validation of the Spanish Incisional Hernia Surgery Registry (EVEREG): pilot study

PURPOSE

The Spanish Incisional Hernia Surgery Registry (EVEREG) was promoted by the Abdominal Wall Section of the Spanish Association of Surgeons, starting data collection in July 2012 and currently has more than 14,000 cases. The objective of this study was to validate the data collected through a pilot audit process.

METHODS

A sample of hospitals participating in the EVEREG registry since the beginning was selected. Patients registered in these centers in the 2012-2020 period were included. A stratified random sampling was carried out, with the inclusion of 10% of registered cases per center with a minimum of 20 cases per center. At each participating center, two researchers not belonging to the center undergoing the audit checked (on site or telematically) the concordance between the data in the registry and the data contained in the case history of each patient.

RESULTS

330 patients have been analyzed, out of a total of 2673 registered, in 9 participating centers. The average accuracy has been 95.7%. Incorrect data 1.5% and missing data 2.3% CONCLUSION: The group of pilot hospitals from this EVERG incisional hernia surgery registry shows a very high precision of 95.7%. The confirmation of these findings in all the centers participating in the registry will make it possible to guarantee the quality of the studies made and their comparability with other similar national registries.

TRIAL REGISTRATION

nnTrial registration number: ClinicalTrials.gov ID:NCT03899012.

Effect of kidney replacement therapy modality after first kidney graft failure on second kidney transplantation outcomes

BACKGROUND

There is a lack of information regarding which is the best dialysis technique after kidney transplant (KT) failure. The aim of this study is to compare the effect of kidney replacement therapy modality-peritoneal dialysis (TX-PD-TX), haemodialysis (TX-HD-TX) and preemptive deceased donor retransplantation (TX-TX) on patient survival and second KT outcomes.

METHODS

A retrospective observational study from the Catalan Renal Registry was carried out. We included adult patients with failing of their first KT from 2000 to 2018.

RESULTS

Among 2045 patients, 1829 started on HD (89.4%), 168 on PD (8.2%) and 48 (2.4%) received a preemptive KT. Non-inclusion on the KT waiting list and HD were associated with worse patient survival. For patients included on the waiting list, the probability of human leucocyte antigens (HLA) sensitization and to receive a second KT was similar in HD and PD. A total of 776 patients received a second KT (38%), 656 in TX-HD-TX, 72 in TX-PD-TX and 48 in TX-TX groups. Adjusted mortality after second KT was higher in TX-HD-TX patients compared with TX-TX and TX-PD-TX groups, without differences between TX-TX and TX-PD-TX groups. Death-censored second graft survival was similar in all three groups.

CONCLUSIONS

Our results suggest that after first KT failure, PD is superior to HD in reducing mortality in candidates for a second KT without options for preemptive retransplantation.

OC-081 VALIDATION OF THE DATA QUALITY OF THE SPANISH INCISIONAL HERNIA SURGERY REGISTRY (EVEREG). PILOT STUDY

Aim

The Spanish Incisional Hernia Surgery Registry (EVEREG) is promoted by the Abdominal Wall section of the Spanish Association of Surgeons, starting data collection in July 2012 and currently has more than 13,500 cases.

The objective of this study is to validate the data collected through a pilot audit process

Material & Methods

A sample of hospitals participating in the EVEREG registry since 2012 is selected. Patients registered in these centers in the period 2012–2019 are included. A stratified random sampling is carried out, with the inclusion of 10% of registered cases per center with a minimum of 20.

In the 2020–2021 period, a selection of researchers, different from that of the center to be audited, checks the concordance between the registry data and the data collected in the patient's clinical history, either in person or online.

Results

330 patients have been analyzed, out of a total of 2673 registered, in 9 participating centers. The average accuracy has been 95.7% (99.1–79.35%). With 1.5% incorrect data and 2.28% missing data

Conclusions

This is the first validity study of an abdominal wall registry

The accuracy greater than 95% obtained allows us to determine an excellent quality in the data collection of the EVEREG registry. We believe that the confirmation of these data in all the centers participating in the registry would guarantee the quality of the studies carried out and their comparison with other international registries

Mortality in elderly patients starting hemodialysis program

BACKGROUND

The incidence of older patients over 80 years old with chronic kidney disease who start hemodialysis (HD) program has been increasing in the last decade.

METHODS

We aimed to identify risk factors for morbidity and mortality in patients older than 80 years with end-stage renal disease who started HD. We conducted a retrospective observational study of the Catalan Renal registry (RMRC).

RESULTS

A total of 2833 patients equal or older than 80 years (of 15,137) who started HD between 2002 and 2019 from the RMRC were included in the study. In this group, the first dialysis was performed through an arteriovenous fistula in 44%, percutaneous catheter in 28.2%, and tunneled catheter in 26.6%. Conventional dialysis was used in 65.7% and online HD in 34.3%. The most frequent cause of death was cardiac disease (21.8%), followed by social problems (20.4%) and infections (15.9%). Overall survival in older HD during the first year was 84% versus 91% in younger than 80 years (p < 0.001). Cox regression analysis identified the start of HD in the period 2002-2010, chronic obstructive pulmonary disease (COPD), and the onset of HD through vascular graft depicted as risk factors for first-year mortality after dialysis initiation in patients older than 80 years with end-stage renal disease who started HD.

CONCLUSIONS

In conclusion, patients older than 80 years who started HD program had higher mortality, especially those who presented exacerbation of kidney disease, those with COPD, and those who started with a vascular graft.

Improved short-term outcomes of kidney transplants in controlled donation after the circulatory determination of death with the use of normothermic regional perfusion

Normothermic regional perfusion (NRP) allows the in situ perfusion of organs with oxygenated blood in donation after the circulatory determination of death (DCDD). We aimed at evaluating the impact of NRP on the short-term outcomes of kidney transplants in controlled DCDD (cDCDD). This is a multicenter, nationwide, retrospective study comparing cDCDD kidneys obtained with NRP versus the standard rapid recovery (RR) technique. During 2012-2018, 2302 cDCDD adult kidney transplants were performed in Spain using NRP (n = 865) or RR (n = 1437). The study groups differed in donor and recipient age, warm, and cold ischemic time and use of ex situ machine perfusion. Transplants in the NRP group were more frequently performed in high-volume centers (≥90 transplants/year). Through matching by propensity score, two cohorts with a total of 770 patients were obtained. After the matching, no statistically significant differences were observed between the groups in terms of primary nonfunction (p = .261) and mortality at 1 year (p =  .111). However, the RR of kidneys was associated with a significantly increased odds of delayed graft function (OR 1.97 [95% CI 1.43-2.72]; p < .001) and 1-year graft loss (OR 1.77 [95% CI 1.01-3.17]; p = .034). In conclusion, compared with RR, NRP appears to improve the short-term outcomes of cDCDD kidney transplants.

Kidney transplant outcomes in elderly recipients with controlled donation after circulatory death or donation after brain death donors: a registry cohort study

The number of kidney transplant (KT) procedures with controlled donation after circulatory death (cDCD) donors has exponentially increased in Spain in recent years, with a parallel increase in donor and recipient acceptance criteria. The outcomes of cDCD-KT have been reported to be comparable to those of KT with donation after brain death (DBD) donors. However, studies in elderly recipients have yielded contradictory results. We performed a registry analysis of 852 KT recipients aged ≥65 years (575 in the DBD-KT group, 277 in the cDCD-KT group) in Catalonia, Spain. Clinical outcomes and survival were compared between DBD-KT and cDCD-KT recipients. The donor and recipient ages were similar between the two groups (71.5 ± 8.7 years for donors, 70.8 ± 4.1 years for recipients). Delayed graft function (DGF) was more frequent among cDCD-KT recipients, without a difference in the rate of primary nonfunction. The 3-year patient and death-censored graft survival rates were similar between DBD-KT and cDCD-KT recipients (78.8% vs. 76.4% and 90.3% vs. 86.6%, respectively). In multivariable analysis, previous cardiovascular disease and DGF were independent risk factors for patient death. The type of donation (cDCD vs. DBD) was not an independent risk factor for patient survival or graft loss. cDCD-KT and DBD-KT provide comparable patient and graft survival in elderly recipients.

Deciphering transplant outcomes of expanded kidney allografts donated after controlled circulatory death in the current transplant era. A call for caution

Outcomes of kidney transplantation (KT) after controlled circulatory death (cDCD) with highly expanded criteria donors (ECD) and recipients have not been thoroughly evaluated. We analyzed in a multicenter cohort of 1161 consecutive KT, granular baseline donor and recipient factors predicting transplant outcomes, selected by bootstrapping and Cox proportional hazards, and were validated in a contemporaneous European KT cohort (n = 1585). 74.3% were DBD and 25.7% cDCD-KT. ECD-KT showed the poorest graft survival rates, irrespective of cDCD or DBD (log-rank < 0.001). Besides standard ECD classification, dialysis vintage, older age, and previous cardiovascular recipient events together with low class-II-HLA match, long cold ischemia time and combining a diabetic donor with a cDCD predicted graft loss (C-Index 0.715, 95% CI 0.675-0.755). External validation showed good prediction accuracy (C-Index 0.697, 95%CI 0.643-0.741). Recipient older age, male gender, dialysis vintage, previous cardiovascular events, and receiving a cDCD independently predicted patient death. Benefit/risk assessment of undergoing KT was compared with concurrent waitlisted candidates, and despite the fact that undergoing KT outperformed remaining waitlisted, remarkably high mortality rates were predicted if KT was undertaken under the worst risk-prediction model. Strategies to increase the donor pool, including cDCD transplants with highly expanded donor and recipient candidates, should be performed with caution.

Nature-based solutions in the urban context: terminology, classification and scoring for urban challenges and ecosystem services

The concept of Nature-Based Solutions (NBS) has emerged to foster sustainable development by transversally addressing social, economic, and environmental urban challenges. However, there is still a considerable lack of agreement on the conceptualization of NBS, especially concerning typologies, nomenclature, and performance assessments in terms of ecosystem services (ES) and urban challenges (UC). Therefore, this article consolidates the knowledge from 4 European projects to set a path for a common understanding of NBS and thus, facilitate their mainstreaming. To do so, firstly, we performed elicitation workshops to develop an integrative list of NBS, based on the identification of overlaps among NBS from different projects. The terminologies were formalized via web-based surveys. Secondly, the NBS were clustered, following a conceptual hierarchical classification. Thirdly, we developed an integrative assessment of NBS performance (ES and UC) based on the qualitative evaluations from each project. Afterwards, we run a PCA and calculated the evenness index to explore patterns among NBS. The main conceptual advancement resides in providing a list of 32 NBS and putting forward two novel NBS categories: NBS units (NBS_u) that are stand-alone green technologies or green urban spaces, which can be combined with other solutions (nature-based or not); NBS interventions (NBS_i) that refer to the act of intervening in existing ecosystems and in NBS_u, by applying techniques to support natural processes. The statistical analysis suggests that NBS_u are more versatile than NBS_i in terms of UC and ES. Moreover, the results of the integrative assessment of NBS performance suggest a greater agreement concerning the role of NBS in addressing environmental UC, cultural and regulating ES than regarding socio-economic UC and supporting and provision ES. Finally, the 'green factor' and the replication of non-intensive practices occurring in nature seem to be key criteria for practitioners to identify a particular solution as an NBS.

MO768VASCULAR ACCESS FOR PEDIATRIC HEMODIALYSIS PATIENTS IN CATALONIA: ANALYSIS OF DATA FROM THE CATALAN RENAL REGISTRY (1997-2018)

Background

The vascular access (VA) is the life-line for children with kidney failure (KT) on hemodialysis (HD). The European Society for Paediatric Nephrology Dialysis Working Group suggested that children requiring HD start with a functioning arteriovenous fistula (AVF) but a tunnelled catheter (TC) can be placed instead where a short period on HD is anticipated before kidney transplantation (KT) (NDT 2019; 34: 1746–1765).

Aims

To analyze the type of VA used by incident and prevalent KF pediatric patients (pts) treated with HD in Catalonia

Method

Data from the Catalan Renal Registry of KF pts younger than 18 years of age undergoing kidney replacement therapy (KRT) were examined for a 22-year period.

Results

The modality of KRT used by incident KF pediatric pts has changed significantly over time: the percentage of children who started KRT through HD decreased progressively from 89.9% during the 1984-1989 period to 38.2% during the 2014-2018 period and, conversely, the percentage of children who started KRT by using pre-emptive KT increased progressively from 5.1% to 42.6% between the same periods (for both comparisons, p&lt;0.001). During 2018, 18 children started KRT (rate: 12.8 per milion of population, pmp) by using pre-emptive KT (n=8, 44.4%), peritoneal dialysis (n=5, 27.8%) or HD (n=5, 27.8%).

From 1997 to 2018, 112 KF pediatric pts started KRT by using HD (mean age 9.4±6,0 yr, male 58.9%, glomerular disease 36.8%). Most children started HD through an AVF during the 1997-2001 period (56.5%) but this percentage decreased over time and no children used an AVF for starting HD during the 2012-2018 period. On the contrary, the percentage of children starting HD through a TC increased progressively from 8.7% to 72.2% between the same periods (for both comparisons, p&lt;0.001). No significant changes over time were recorded regarding untunnelled catheter (UC) utilization from 34.8% (1997-2001 period) to 27.8% (2012-2018 period) (p=0.57). Considering two age groups (0-6 vs 7-18 years), VA distribution was the following (%): 23.3 vs 76.7 for UC, 47.2 vs 52.8 for TC and 26.3 vs 73.7 for AVF (p=0.058). Regarding KF presentation, UC was used mainly to initiate HD in crashlanders (53.3%) and AVF was used mainly to start HD in children with steady kidney disease progression (63.2%) (p=0.003).

The KRT modality of using prevalent KF pediatric pts has also changed significantly over time: pts on HD decreased from 34.9% (n=15, mean age 13.5 yr) in 1997 to 4.7% (n=5, mean age 11.6 yr) in 2018 and, conversely, pts with a kidney graft increased from 62.8% (n=27, mean age 13.7 yr) to 92.4% (n=98, mean age 11.2 yr) during the same period (for both comparisons, p&lt;0.001). The percentage of children dialyzed through an AVF decreased progressively from 1997 (100%) to 2018 (0%) (p&lt;0.001). All prevalent HD pts were dialyzed through a catheter in 2018.

The KT rate increased significantly from 5.4 pmp (n=6) in 1997 to 17.1 pmp (n=24) in 2018 (p=0.007). The median time on HD (months) prior to the first KT decreased progressively from 23.1 during the 1984-1989 period to 6.6 during the 2014-2018 period (p&lt;0.001).

Conclusions

1) The VA profile of pediatric population treated with HD in Catalonia has radically changed over time. 2) Since 2012, AVF has practically disappeared as the VA in the incident and prevalent pediatric population on HD. 3) Almost all children treated by HD since 2012 were dialyzed through a catheter due to the short waiting time before receiving a kidney graft. 4) The high KT rate was a determining factor in choosing the AV type in the pediatric population treated with HD in Catalonia.

Effects of Fouling Management and Net Coating Strategies on Reared Gilthead Sea Bream Juveniles

Simple Summary

Fish farming strives to cover the increasing demand for aquatic food sources as a result of global population growth. As a primary sector industry, aquaculture profit margins are narrow. Fouling management is an issue and represents a significant part of the operational cost of this activity. Over the last 30 years, this problem has been approached from different perspectives and the use of copper dioxide to control fouling production has been the most successful strategy. However, far beyond being the definite solution, the use of copper involves several concerns, and so the aquaculture industry has been continuously trying to find a reliable alternative. Coating the nets and cleaning on-site was adopted by the industry as a realistic alternative around 2015. This work contrasts these two fouling management strategies, simulating real working conditions by analysing the results from different perspectives. The conclusions from this work suggest a combination of both as a promising future alternative.

Abstract

In aquaculture, biofouling management is a difficult and expensive issue. Cuprous oxide has been commonly used to prevent fouling formation. To cheapen net management and reduce the use of copper, the industry has proposed several alternatives. Currently, polyurethane coatings are being explored and commercially implemented. With this alternative, net cleaning is done in situ, reducing the number of nets necessary to raise a batch, thus ideally reducing operational costs. This pilot study compared this new strategy to the use of cuprous oxide. The results show that nets treated with antifouling perform better and bioaccumulation of copper in fish tissues do not pose health risks to fish. Alternatives involving on-site cleaning need to improve efficiency. Although the conditions of this work are not completely comparable to commercial aquaculture conditions, the results might indicate the strengths and constrains of the solutions tested in real life.

A redefinition of the genus Troglocharinus Reitter, 1908, with description of new species (Coleoptera, Leiodidae, Cholevinae, Leptodirini)

We redefine the genus Troglocharinus Reitter, 1908 based on a phylogenetic analysis with a combination of mitochondrial and molecular data. We recovered the current Speonomites mengeli (Jeannel, 1910) and S. mercedesi (Zariquiey, 1922) as valid, separate species within the Troglocharinus clade, not directly related to Speonomites Jeannel, 1910, a finding corroborated by a detailed study of the male and female genitalia. In consequence, we reinstate Speonomus mercedesi Zariquiey, 1922 stat. nov. as a valid species, transfer both of them to the genus Troglocharinus, T. mengeli (Jeannel, 1910) comb. nov. and T. mercedesi (Zariquiey, 1922) comb. nov., and redescribe the genus. The study of new material from the distribution area of the former S. mengeli revealed the presence of two undescribed species, T. sendrai sp. nov. and T. fadriquei sp. nov., which we describe herein. We designate the lectotype of Speonomus vinyasi Escolà, 1971 to fix its identity, as among its syntypes there are two different species. In agreement with the results of the phylogenetic analyses we establish the synonymy between the genus Speonomites and Pallaresiella Fresneda, 1998 syn. nv.

Impact of obesity on the evolution of outcomes in peritoneal dialysis patients

Background

Some studies reveal that obesity is associated with a decrease in mortality in haemodialysis (HD) patients. However, few studies have addressed the association between body mass index (BMI) and peritoneal dialysis (PD) patients.

Methods

We performed this longitudinal, retrospective study to evaluate the impact of obesity on PD patients, using data from the Catalan Registry of Renal Patients from 2002 to 2015 (n = 1573). Obesity was defined as BMI ≥30; low weight: BMI <18.5; normal range: BMI = 18.5–24.99; and pre-obesity: BMI = 25–29.99 kg/m². Variations in BMI were calculated during follow-up. The main outcomes evaluated were the technique and patient survival.

Results

Obesity was observed in 20% of patients starting PD. We did not find differences in sex or PD modality, with the obesity group being older (65.9% are ≥55 years versus 59% non-obese, P = 0.003) and presenting more diabetes mellitus and cardiovascular disease (CVD) (47.9% obese versus 25.1% non-obese and 41.7% versus 31.5%, respectively). We did not observe differences in haemoglobin, albumin and Kt/V in obese patients. Regarding peritonitis rate, we did not find any difference between groups, presenting more peritonitis patients on continuous ambulatory peritoneal dialysis and aged ≥65 years [sub-hazard ratio (SHR) = 1.75, P = 0.000 and SHR = 1.56, P = 0.009]. In relation to technique survival, we found higher transfer to HD in the obese group of patients in the univariate analysis, which was not confirmed in the multivariate analysis (SHR = 1.12, P = 0.4), and we did not find differences in mortality rate. In relation to being transplanted, the underweight group, elderly and patients with CVD or diabetic nephropathy presented less probability to undergo kidney transplantation (SHR = 0.65, 0.24, 0.5 and 0.54, P < 0.05). Obese patients did not present differences in survival with weight changes but in normal-weight patients, a gain of 7% of the basal weight during the first year had a protective effect on death risk (hazard ratio 0.6, P = 0.034).

Conclusions

Obese and non-obese patients starting on PD had similar outcomes.

P1312EFFECT OF KIDNEY TRANSPLANTATION RATE ON THE ARTERIOVENOUS FISTULA RATE IN PREVALENT HEMODIALYSIS PATIENTS: ANALYSIS OF DATA FROM THE CATALAN RENAL REGISTRY (1997-2017)

Background

Kidney transplantation (KT) is considered to be the best option of renal replacement therapy (RRT) for most end-stage renal disease (ESRD) patients (pts). Furthermore, arteriovenous fistula (AVF) is considered to be the best vascular access (VA) for most hemodialysis (HD) pts.

Aims

To analyze the effect of KT rate on the AVF rate in prevalent HD pts. In addition, the likelihood of receiving a kidney graft (KG) over time according to the first VA used to start HD program was also evaluated

Method

Data from the Catalan Registry of ESRD pts treated with either KT or HD were examined for a 20-year period

Results

The functioning KG rate increased progressively from 40.5% (n=2211) in 1997 to 57.0% (n=6149) in 2017 and, conversely, the AVF rate in prevalent HD patients decreased progressively from 86.0% (n=2609) to 63.2% (n=2546) during the same period (for both comparisons, p &lt; 0.001).

The characteristics of all prevalent HD pts dialyzed in 1997 (n=3104) vs 2017 (n=4205) were different regarding age 62.6±15.3 vs 70.3±14.2 yr, diabetic nephropathy (DN) 13.2% vs 21.8% and cardiovascular disease (CD) 67.6% vs 75.8% (for all comparisons, p&lt;0.001). On December 31, 2017 (maximum KT rate), the characteristics of KG recipients were different compared with prevalent HD pts dialyzed through either an AVF or a tunneled catheter (n=1145): age 57.4±14.5 vs 69.9±13.8 vs 72.0±14.6 yr, DN 9.5% vs 21.7% vs 22.5%, CD 38.6% vs 74.3% vs 83.7% (for all comparisons, p&lt;0.001).

By analyzing the likelihood of prevalent pts performing HD through an AVF, we saw it was lower in pts with DN (OR: 0.86; 95% CI: 0.79-0.94, p=0.001) and it decreased progressively as they got older (reference &gt;74 yr): &lt;44 yr (OR:1.55, 95% CI: 1.41-1.70, p&lt;0.001), 45-64 yr (OR: 1.47, 95% CI: 1.38-1.56, p&lt;0.001) and 65-74 yr (OR: 1.22, 95% CI: 1.17-1.28, p&lt;0.001). This probability was higher in males (OR: 1.84, 95% CI: 1.73-1.95, p&lt;0.001), pts with polycystic kidney disease (OR: 1.54, 95% CI: 1.35-1.77, p&lt;0.001) and pts without CD (OR: 1.32; 95% CI: 1.27-1.38, p&lt;0.001) and it increased according to the time on RRT (reference &lt; 1 month): &gt;12 m (OR: 2.39, 95% CI: 2.17-2.64, p&lt;0.001). In addition, this likelihood decreased progressively as the percentage of patients with a functioning KG increased (reference &gt;55%): 40-45% (OR: 3.26, 95% CI: 3.05-3.48, p&lt;0.001), 45-50% (OR: 1.82, 95% CI: 1.73-1.92, p&lt;0.001) and 50-55% (OR: 1.27, 95% CI: 1.21-1.33, p&lt;0.001).

The rate of prevalent HD pts waitlisted for KT and dialyzed through AVF decreased progressively from 94.5% (639/676, 1997) to 77.9% (491/630, 2017). In parallel, but always remaining at a lower level, the rate of prevalent HD patients not waitlisted for KT and dialyzed through AVF also decreased progressively from 83.6% (1970/2357) to 60.5% (2055/3399) during the same period (for all comparisons, p&lt;0.001). Considering the prevalent HD pts during the period 2014-2017 (n=4029), significant differences were observed between HD pts waitlisted (n=630, 15.6%) and not-waitlisted (n=3399, 84.4%) for KT regarding age (58.2±12.9 vs 72.8±13.1 yr), DN (16.2% vs 23.0%), CD (59.5% vs 80.5%) and distribution of AVF (77.9% vs 60.5%) or tunneled catheter (16.5% vs 30.6%) (for all comparisons, p&lt;0.001).

During the period 2012-2014, incident pts starting HD through an AVF (n=1026) had a significant higher likelihood of receiving a KG over time (HR: 1.68, 95% CI: 1.41-2.00, p&lt;0.001) in comparison to pts who initiated HD through a catheter (n=1408).

Conclusion

1) The fall of prevalent HD pts with AVF over time could be associated with a progressive worsening of their clinical profiles along with the increasing rate of KG recipients. 2) In addition to some demographic and clinical characteristics of prevalent HD pts, the annual KT rate was also a determining factor in their AVF rate. 3) Starting HD program through an AVF was independently associated with a greater likelihood of receiving a KG over time as compared to starting HD through a catheter.

Position paper - progress towards standards in integrated (aerobic) MBR modelling

Membrane bioreactor (MBR) models are useful tools for both design and management. The system complexity is high due to the involved number of processes which can be clustered in biological and physical ones. Literature studies are present and need to be harmonized in order to gain insights from the different studies and allow system optimization by applying a control. This position paper aims at defining the current state of the art of the main integrated MBR models reported in the literature. On the basis of a modelling review, a standardized terminology is proposed to facilitate the further development and comparison of integrated membrane fouling models for aerobic MBRs.

Beyond survival experiments: using biomarkers of oxidative stress and neurotoxicity to assess vulnerability of subterranean fauna to climate change

Accurate assessments of species vulnerability to climate change need to consider the physiological capacity of organisms to deal with temperature changes and identify early signs of thermally induced stress. Oxidative stress biomarkers and acetylcholinesterase activity are useful proxies of stress at the cellular and nervous system level. Such responses are especially relevant for poor dispersal organisms with limited capacity for behavioural thermoregulation, like deep subterranean species. We combined experimental measurements of upper lethal thermal limits, acclimation capacity and biomarkers of oxidative stress and neurotoxicity to assess the impact of heat stress (20°C) at different exposure times (2 and 7 days) on the Iberian endemic subterranean beetle Parvospeonomus canyellesi. Survival response (7 days of exposure) was similar to that reported for other subterranean specialist beetles (high survival up to 20°C but no above 23°C). However, a low physiological plasticity (i.e. incapacity to increase heat tolerance via acclimation) and signs of impairment at the cellular and nervous system level were observed after 7 days of exposure at 20°C. Such sublethal effects were identified by significant differences in total antioxidant capacity, glutathione S-transferase activity, the ratio of reduced to oxidized forms of glutathione and acetylcholinesterase activity between the control (cave temperature) and 20°C treatment. At 2 days of exposure, most biomarker values indicated some degree of oxidative stress in both the control and high-temperature treatment, likely reflecting an initial altered physiological status associated to factors other than temperature. Considering these integrated responses and the predicted increase in temperature in its unique locality, P. canyellesi would have a narrower thermal safety margin to face climate change than that obtained considering only survival experiments. Our results highlight the importance of exploring thermally sensitive processes at different levels of biological organization to obtain more accurate estimates of the species capacity to face climate change.

The impact of wastewater matrix on the degradation of pharmaceutically active compounds by oxidation processes including ultraviolet radiation and sulfate radicals

Ultraviolet radiation (UV)-activated peroxydisulfate (PDS) and peroxymonosulfate (PMS) advanced oxidation processes were examined for their capacity to remove nine pharmaceutically active compounds (PhACs) from secondary effluent. The effect of operational parameters (initial oxidant concentration, UV exposure time, pH, common coexisting anions and effluent organic matter (EfOM)) on UV/PDS and UV/PMS treatment efficiency was investigated in a collimated beam device housing a low-pressure mercury UV lamp emitting light at 253.7 nm. Both AOPs achieved high removals (>90%) when applied to pure water. Under otherwise similar conditions the removal percentage fell by 20-30% due to the scavenging of effluent organic matter (EfOM) in secondary effluent. Finally, eliminating EfOM but maintaining the inorganic composition, the radical scavenging effect was reduced and 98.3% and 85.6% average removals were obtained by UV/PDS and UV/PMS, respectively. Increasing pH improved degradation of several PhACs containing amine groups. Higher oxidant dosages created only a significant benefit in UV/PDS. The chloride anion produced a negligible effect on both processes, while higher nitrate concentrations increased removal percentage but did not affect degradation rate constants. Finally and surprisingly, the addition of bicarbonate had the strongest positive impact on the degradation kinetics observed, even stronger than the elimination of EfOM from secondary effluent.

Effects of body weight variation in obese kidney recipients: a retrospective cohort study

Background

Obese kidney allograft recipients have worse results in kidney transplantation (KT). However, there is lack of information regarding the effect of body mass index (BMI) variation after KT. The objective of the study was to evaluate the effects of body weight changes in obese kidney transplant recipients.

Methods

In this study we used data from the Catalan Renal Registry that included KT recipients from 1990 to 2011 (n = 5607). The annual change in post-transplantation BMI was calculated. The main outcome variables were delayed graft function (DGF), estimated glomerular filtration rate (eGFR) and patient and graft survival.

Results

Obesity was observed in 609 patients (10.9%) at the time of transplantation. The incidence of DGF was significantly higher in obese patients (40.4% versus 28.3%; P < 0.001). Baseline obesity was significantly associated with worse short- and long-term graft survival (P < 0.05) and worse graft function during the follow-up (P < 0.005). BMI variations in obese patients did not improve eGFR or graft or patient survival.

Conclusions

Our conclusion is that in obese patients, decreasing body weight after KT does not improve either short-term graft outcomes or long-term renal function.

Occurrence and human health implications of chemical contaminants in vegetables grown in peri-urban agriculture

Recent studies have proven that vegetables cultivated in peri-urban areas are exposed to a greater concentration of organic microcontaminants (OMCs) and trace elements (TEs) than those grown in rural areas. In this study, the occurrence and human health risk of chemical contaminants (16 TEs and 33 OMCs) in edible parts of lettuce, tomato, cauliflower, and broad beans from two farm fields in the peri-urban area of the city of Barcelona and one rural site outside the peri-urban area were assessed. The concentration of TEs and OMCs (on fresh weight basis) ranged from non-detectable to 17.4 mg/kg and from non-detectable to 256 μg/kg, respectively. Tomato fruits showed the highest concentration of TEs and OMCs. Principal component analysis indicated that the occurrence of chemical contaminants in vegetables depended on the commodity rather than the location (peri-urban vs rural). Risk assessment using hazardous quotient (HQ) and threshold of toxicological concern (TTC) approaches showed that the risk for the consumption of target vegetables in the peri-urban area was low and similar to that observed for the rural site. Total HQ values for TEs were always below 1, and a minimum consumption of 150 g/day for children and 380 g/day for adults is required to reach the TTC due to the presence of pesticides. Further studies are needed to estimate the combined effect of TEs and OMCs on human health.

Occurrence and bioaccumulation of chemical contaminants in lettuce grown in peri-urban horticulture

Peri-urban horticulture performs environmental and socio-economic functions and provides ecological services to nearby urban areas. Nevertheless, industrialization and water pollution have led to an increase in the exposure of peri-urban vegetables to contaminants such as trace elements (TEs) and organic microcontaminants (OMCs). In this study, the occurrence of chemical contaminants (i.e., 16 TEs, 33 OMCs) in soil and lettuce leaves from 4 farm fields in the peri-urban area of the city of Barcelona was assessed. A rural site, outside the peri-urban area of influence, was selected for comparison. The concentration of TEs and OMCs ranged from non-detectable to 803 mg/kg dw and from non-detectable to 397 μg/kg dw respectively in the peri-urban soil, and from 6 · 10-5 to 4.91 mg/kg fw and from non-detectable to 193 μg/kg fw respectively in lettuce leaves. Although the concentration of Mo, Ni, Pb, and As in the soil of the peri-urban area exceeded the environmental quality guidelines, their occurrence in lettuce complied with human food standards (except for Pb). The many fungicides (carbendazim, dimetomorph, and methylparaben) and chemicals released by plastic pipelines (tris(1-chloro-2-propyl)phosphate, bisphenol F, and 2-mercaptobenzothiazole) used in agriculture were prevalent in the soil and the edible parts of the lettuce. The occurrence of these chemical pollutants in the peri-urban area did not affect the chlorophyll, lipid, or carbohydrate content of the lettuce leaves. PCA (Principal Component Analysis) showed that soil pollution, fungicide application, and irrigation water quality are the most relevant factors determining the presence of contaminants in crops.

Occurrence of chemical contaminants in peri-urban agricultural irrigation waters and assessment of their phytotoxicity and crop productivity

Water scarcity and water pollution have increased the pressure on water resources worldwide. This pressure is particularly important in highly populated areas where water demand exceeds the available natural resources. In this regard, water reuse has emerged as an excellent water source alternative for peri-urban agriculture. Nevertheless, it must cope with the occurrence of chemical contaminants, ranging from trace elements (TEs) to organic microcontaminants. In this study, chemical contaminants (i.e., 15 TEs, 34 contaminants of emerging concern (CECs)), bulk parameters, and nutrients from irrigation waters and crop productivity (Lycopersicon esculentum Mill. cv. Bodar and Lactuca sativa L. cv. Batavia) were seasonally surveyed in 4 farm plots in the peri-urban area of the city of Barcelona. A pristine site, where rain-groundwater is used for irrigation, was selected for background concentrations. The average concentration levels of TEs and CECs in the irrigation water impacted by treated wastewater (TWW) were 3 (35±75μgL^-1) and 13 (553±1050ngL^-1) times higher than at the pristine site respectively. Principal component analysis was used to classify the irrigation waters by chemical composition. To assess the impact of the occurrence of these contaminants on agriculture, a seed germination assay (Lactuca sativa L) and real field-scale study of crop productivity (i.e., lettuce and tomato) were used. Although irrigation waters from the peri-urban area exhibited a higher frequency of detection and concentration of the assessed chemical contaminants than those of the pristine site (P1), no significant differences were found in seed phytotoxicity or crop productivity. In fact, the crops impacted by TWW showed higher productivity than the other farm plots studied, which was associated with the higher nutrient availability for plants.

Incorporating model uncertainty into the evaluation of interventions to reduce microcontaminant loads in rivers

Models of microcontaminant fate and transport in wastewater treatment plants (WWTPs) and rivers have been developed and used to assist decision-making in the field of water management. These models come with parameter uncertainties that must be properly incorporated in the decision-making process. The main goal of this study is to evaluate how the magnitudes of key model parameter uncertainties influence the selection of end-of-pipe interventions (at WWTPs) designed to reduce the microcontaminant loads in rivers. We developed a model that describes the fate and removal of pharmaceuticals in WWTPs and the river network based on 3 key parameters: human pharmaceutical consumption and excretion (F) and the pharmaceutical degradation constants in WWTPs (k_WWTP) and rivers (k_river). We modelled the fate and transport of diclofenac in the Llobregat River basin (NE Spain). We calibrated the model using a Bayesian approach, which resulted in an accurate prediction of measured diclofenac loads at 9 locations along the Llobregat River and at the influents and effluents of 2 WWTPs (R² = 0.95). Using different scenarios, we evaluated three levels of uncertainty in the key model parameters. The first level of uncertainty corresponded to the reference distributions obtained from the Bayesian calibration. Then, for each parameter, we generated a narrower PDF (decreased uncertainty with respect to the reference) and a wider PDF (increased uncertainty). For each level of uncertainty, we evaluated increasing removal efficiencies of diclofenac at the WWTPs, from 38% to 98%. We assumed that removal efficiencies of up to 75% can be achieved by upgrading secondary treatment; beyond 75%, tertiary treatment is needed. The scenario analysis showed that achieving diclofenac removal efficiencies corresponding to tertiary treatment results in apparent concentration reductions (statistically significant differences relative to the reference situation), regardless of the level of uncertainty applied to the model parameters. However, upgrades in the secondary treatment resulted in apparent reductions only in the case of reduced uncertainty. We concluded that model uncertainty greatly influences the decisions that river basin authorities must make to reduce the microcontaminant loads released by WWTPs into rivers. In addition, we discussed research priorities to help reduce model uncertainty and thereby make more appropriate decisions.

Resilience theory incorporated into urban wastewater systems management. State of the art

Government bodies, utilities, practitioners, and researchers have growing interest in the incorporation of resilience into wastewater management. Since resilience is a multidisciplinary term, it is important to review what has been achieved in the wastewater sector, and describe the future research directions for the forthcoming years. This work presents a critical review of studies that deal with resilience in the wastewater treatment sector, with a special focus on understanding how they addressed the key elements for assessing resilience, such as stressors, system properties, metrics and interventions to increase resilience. The results showed that only 17 peer-reviewed papers and 6 relevant reports, a small subset of the work in wastewater research, directly addressed resilience. The lack of consensus in the definition of resilience, and the elements of a resilience assessment, is hindering the implementation of resilience in wastewater management. To date, no framework for resilience assessment is complete, comprehensive or directly applicable to practitioners; current examples are lacking key elements (e.g. a comprehensive study of stressors, properties and metrics, examples of cases study, ability to benchmark interventions or connectivity with broader frameworks). Furthermore, resilience is seen as an additional cost or extra effort, instead of a means to overcome project uncertainty that could unlock new opportunities for investment.

Death of recipients after kidney living donation triples donors' risk of dropping out from follow-up: a retrospective study

Although kidney transplantation from the donation of a living donor is a safe treatment for end-stage renal disease, inferences about safety of living kidney donors might be biased by an informative censoring caused by the noninclusion of a substantial percentage of donors lost to follow-up. With the aim of assessing the presence of a potential informative censoring in living kidney donation outcomes of Catalan donors for a period of 12 years, 573 donors followed and lost to follow-up were compared. Losses of follow-up over time were also assessed by univariate and multivariate survival analysis, along with Cox regression. Younger and older ages, and the death of their recipient differentiated those donors who were lost to follow-up over time. The risk of dropping out from follow-up was more than twofold for the youngest and oldest donors, and almost threefold for those donors whose recipient died. Results of studies on postdonation outcomes of Catalan living kidney donors might have overlooked older and younger cases, and, remarkably, a percentage of donors whose recipient died. If these donors showed a higher incidence of psychological problems, conclusions about living donors' safety might be compromised thus emphasizing the necessity of sustained surveillance of donors and prompt identification of these cases.

Effect of soil biochar concentration on the mitigation of emerging organic contaminant uptake in lettuce

Although crop uptake of emerging organic contaminants (EOC) from irrigation water and soils has been previously reported, successful mitigation strategies have not yet been established. In this study, soil was amended with a wood-based biochar (BC) at two rates (0, 2.5 and 5% w/w) to evaluate the effect on mitigation of EOC uptake (i.e. bisphenol A, caffeine, carbamazepine, clofibric acid, furosemide, ibuprofen, methyl dihydrojasmonate, tris(2-chloroethyl)phosphate, triclosan, and tonalide) in lettuce (Lactuca sativa L.). After 28 days of irrigation with water containing EOCs at 15μgL-1, the average EOC concentration in roots and leaves decreased by 20-76% in biochar amended soil relative to non BC-amended soil. In addition, the enantiomeric fractions (EF) of ibuprofen (IBU) in biochar amended soils (EF=0.58) and unamended soils (EF=0.76) suggest that the IBU sorbed fraction in BC is more recalcitrant to its biodegradation.

Validation of a decision support tool for wastewater treatment selection

Wastewater treatment selection is a complex task usually addressed by applying separate tools for the correct assessment of multi-criteria evaluation. Novedar_EDSS integrates technical, environmental, economic and social assessment capabilities in one single platform. The aim of this work is to evaluate and demonstrate the capabilities of this environmental decision support system (EDSS). For that purpose, 4 case studies of real projects were selected to validate the results in the EDSS by comparing them with those from the study of alternatives performed by the decision makers. Moreover, 1 conceptual case study was applied to support the selection of the most properly strategy for plant retrofitting. Results have demonstrated that the EDSS provides key aspects when deciding the retrofitting process to apply and, when compared to real projects, it recommends analogue treatments as those applied in the projects, ranking them in the same order. Therefore, results in the validation process performed show that this tool provides a reliable basis to support decision makers to select properly treatment alternatives in wastewater treatment plant pre-design.

Placing ecosystem services at the heart of urban water systems management

Current approaches have failed to deliver a truly integrated management of the different elements of the urban water system, such as freshwater ecosystems, drinking water treatment plants, distribution networks, sewer systems and wastewater treatment plants. Because the different parts of urban water have not been well integrated, poor decisions have been made for society in general, leading to the misuse of water resources, the degradation of freshwater ecosystems and increased overall treatment costs. Some attempts to solve environmental issues have adopted the ecosystem services concept in a more integrated approach, however this has rarely strayed far away from pure policy, and has made little impact in on-the-ground operational matters. Here, we present an improved decision-making framework to integrate the management of urban water systems. This framework uses the ecosystem service concept in a practical way to make a better use of both financial and water resources, while continuing to preserve the environment.

Survival Benefit From Kidney Transplantation Using Kidneys From Deceased Donors Aged ≥75 Years: A Time-Dependent Analysis

Patients with end-stage renal disease have longer survival after kidney transplantation than they would by remaining on dialysis; however, outcome with kidneys from donors aged ≥75 years and the survival of recipients of these organs compared with their dialysis counterparts with the same probability of obtaining an organ is unknown. In a longitudinal mortality study, 2040 patients on dialysis were placed on a waiting list, and 389 of them received a first transplant from a deceased donor aged ≥75 years. The adjusted risk of death and survival were calculated by non-proportional hazards analysis with being transplanted as a time-dependent effect. Projected years of life since placement on the waiting list was almost twofold higher for transplanted patients. Nonproportional adjusted risk of death after transplantation was 0.44 (95% confidence interval [CI] 0.61-0.32; p < 0.001) in comparison with those that remained on dialysis. Stratifying by age, adjusted hazard ratios for death were 0.17 (95% CI 0.47-0.06; p = 0.001) for those aged <65 years, 0.56 (95% CI 0.92-0.34; p = 0.022) for those aged 65-69 years and 0.82 (95% CI 1.28-0.52; p = 0.389) for those aged ≥70 years. Although kidney transplantation from elderly deceased donors is associated with reduced graft survival, transplanted patients have lower mortality than those remaining on dialysis.

Estimate of uptake and translocation of emerging organic contaminants from irrigation water concentration in lettuce grown under controlled conditions

The widespread distribution of emerging organic contaminants (EOCs) in the water cycle can lead to their incorporation in irrigated crops, posing a potential risk for human consumption. To gain further insight into the processes controlling the uptake of organic microcontaminants, Batavia lettuce (Lactuca sativa) grown under controlled conditions was watered with EOCs (e.g., non-steroidal anti-inflammatories, sulfonamides, β-blockers, phenolic estrogens, anticonvulsants, stimulants, polycyclic musks, biocides) at different concentrations (0-40μgL(-1)). Linear correlations were obtained between the EOC concentrations in the roots and leaves and the watering concentrations for most of the contaminants investigated. However, large differences were found in the root concentration factors ( [Formula: see text] =0.27-733) and leaf translocation concentration factors ( [Formula: see text] =0-3) depending on the persistence of the target contaminants in the rhizosphere and the specific physicochemical properties of each one. With the obtained dataset, a simple predictive model based on a linear regression and the root bioconcentration and translocation factors can be used to estimate the concentration of the target EOCs in leaves based on the dose supplied in the irrigation water or the soil concentration. Finally, enantiomeric fractionation of racemic ibuprofen from the initial spiking mixture suggests that biodegradation mainly occurs in the rhizosphere.

Experimental early pathogenesis of Streptococcus agalactiae infection in red tilapia Oreochromis spp

Streptococcus agalactiae causes a severe systemic disease in fish, and the routes of entry are still ill-defined. To address this issue, two groups of 33 red tilapia Oreochromis spp. each of 10 g were orally infected with S. agalactiae (n = 30), and by immersion (n = 30), six individuals were control-uninfected fish. Three tilapias were killed at each time point from 30 min to 96 h post-inoculation (pi); controls were killed at 96 h. Samples from most tissues were examined by haematoxylin-eosin (H&E), indirect immunoperoxidase (IPI) and periodic acid-Schiff; only intestine from fish infected by gavage was evaluated by transmission electron microscopy. The results of both experiments suggest that the main entry site of S. agalactiae in tilapia is the gastrointestinal epithelium; mucus seems to play an important defensive role, and environmental conditions may be an important predisposing factor for the infection.

Does the obesity survival paradox of dialysis patients differ with age?

BACKGROUND

The obesity paradox of hemodialysis patients (the association between obesity and survival) could be modified by age. We hypothesize that whereas obesity associates with survival in elderly patients, it behaves as a mortality risk marker in younger individuals.

METHODS

Retrospective study of 2002-2010 adult incident hemodialysis to analyze the relationship between body mass index (BMI) and annual body weight changes with mortality in different age strata.

RESULTS

Included in the study were 6,290 individuals. A progressive decrease in mortality was associated with increasing BMI ranges. Both annual body weight gains and losses were associated with mortality. Similar results were observed in elderly individuals, but in the BMI values of young patients, there were no significant differences in mortality.

CONCLUSION

There is a survival benefit with increasing BMI in patients overall. However, while these results persist in patients >65 years, in young people there are no changes in mortality. Patients with the highest inter-annual variability in weight have an increased risk.

A new species of Laemostenus Bonelli, 1810 (Coleoptera, Carabidae) from Els Ports Natural Park (Catalonia, northeastern Iberian peninsula)

Laemostenus (Antisphodrus) portsensis n. sp. is described from five caves at Els Ports Natural Park. The new taxon can be distinguished from its geographical neighbours, L. (A.) levantinus (Bolívar, 1919) and L. (A.) lassallei Mateu, 1989, by the shape of its head and pronotum, and particularly by the morphology of the male genitalia. The study includes some remarks about the habitat and ecology of the new species.

Evaluation of antibiotic mobility in soil associated with swine-slurry soil amendment under cropping conditions

Interest in identifying pools of antibacterial-resistance genes has grown over the last decade, with veterinary antibiotics (VAs) receiving particular attention. In this paper, a mesoscale study aimed at evaluating the vertical transport of common VAs-namely, fluoroquinolones, tetracyclines, sulfonamides, and lincosamides in agricultural soil subjected to drip irrigation-was performed under greenhouse conditions. Accordingly, leachates of cropped and uncropped soil, amended with swine-slurry leading to 19-38 μg kg(-1) (dry mass) antibiotics in the soil, were analyzed over the course of the productive cycle of a lettuce (42 days) with three sampling campaigns (N = 24). High lincomycin (LCM) concentrations (30-39 μg L(-1)) were detected in the leachates collected from the swine-slurry-amended soil. The highest LCM mass recovered in the leachates (30.1 ± 1.63 %) was obtained from cropped experimental units. In addition, the LCM leaching constant and its leaching potential as obtained from the first-order model were higher in the leachates from the cropped experimental units. Lower concentrations of sulfadimethoxine were also detected in leachates and in soil. Enrofloxacin and oxytetracycline occurred only in soil, which is consistent with high soil interaction.

Age may explain the association of an early dialysis initiation with poor survival

BACKGROUND

Some studies postulate that early dialysis initiation may increase mortality.

AIM

The aim of the present study was to assess to what extent this was due to confounding by age.

DESIGN

Observational retrospective cohort study.

METHODS

We studied all patients starting dialysis therapy between 1 January 1995 and 31 December 2009 in our center. The following variables at dialysis initiation in end-stage renal disease (ESRD) patients were analysed: estimated glomerular filtration rate (eGFR), age, gender, diabetes mellitus, serum albumin, hemoglobin, period of dialysis initiation, history of ischemic heart disease and stroke. Multivariate Cox model was used to calculate adjusted patient survival.

RESULTS

Over the last 15 years, 428 patients initiated dialysis therapy in our reference area. Median eGFR at dialysis initiation was 8.16 ml/min. In the univariate analysis, increased eGFR, age, dialysis initiation 1995-1999/2000-2004, diabetes and history of ischemic heart disease were associated (P < 0.05) with increased mortality in ESRD. Patients that started dialysis program with eGFR > 8.16 were older than those who did it with eGFR < 8.16 (66 vs. 61 years, P < 0.001). The association between mortality and eGFR in the crude multivarite Cox model was lost when the model was adjusted by age. In the multivariate Cox model, dialysis initiation period, serum albumin and history of ischemic heart disease were associated with mortality.

CONCLUSION

History of ischemic heart disease, serum albumin and dialysis start before 2005 were risk factors for mortality in ESRD patients. Older age is usually associated with early dialysis initiation, so age adjustment is needed to perform studies aimed to calculate the effect of eGFR at dialysis initiation on survival.

Towards integrated operation of membrane bioreactors: effects of aeration on biological and filtration performance

Two experimental studies evaluated the effect of aerobic and membrane aeration changes on sludge properties, biological nutrient removal and filtration processes in a pilot plant membrane bioreactor. The optimal operating conditions were found at an aerobic dissolved oxygen set-point (DO) of 0.5 mg O2 L(-1) and a membrane specific aeration demand (SADm) of 1 m h(-1), where membrane aeration can be used for nitrification. Under these conditions, a total flow reduction of 42% was achieved (75% energy reduction) without compromising nutrient removal efficiencies, maintaining sludge characteristics and controlled filtration. Below these optimal operating conditions, the nutrient removal efficiency was reduced, increasing 20% for soluble microbial products, 14% for capillarity suction time and reducing a 15% for filterability. Below this DO set-point, fouling increased with a transmembrane pressure 75% higher. SADm below 1 m h(-1) doubled the values of transmembrane pressure, without recovery after achieving the initial conditions.