Potential and Uncertainties of RejectClass in Acute Kidney Graft Dysfunction: An Independent Validation Study

BACKGROUND

Kidney graft rejections are classified based on the Banff classification. The RejectClass algorithm, initially derived from a cohort comprising mostly protocol biopsies, identifies data-driven phenotypes of acute rejection and chronic pathology using Banff lesion scores. It also provides composite scores for inflammation activity and chronicity. This study independently evaluates the performance of RejectClass in a cohort consisting entirely of indication biopsies.

METHODS

We retrospectively applied RejectClass to 441 patients from the German TRABIO (TRAnsplant BIOpsies) cohort who had received indication biopsies. The primary endpoint was death-censored graft failure during 2 y of follow-up.

RESULTS

The application of RejectClass to our cohort demonstrated moderately comparable phenotypic features with the derivation cohort, and most clusters indicated an elevated risk of graft loss. However, the reproduction of all phenotypes and the associated risks of graft failure, as depicted in the original studies, was not fully accomplished. In contrast, adjusted Cox proportional hazards analyses substantiated that both the inflammation score and the chronicity score are independently associated with graft loss, exhibiting hazard ratios of 1.7 (95% confidence interval, 1.2-2.3; P = 0.002) and 2.2 (95% confidence interval, 1.8-2.6; P < 0.001), respectively, per 0.25-point increment (scale: 0.0-1.0).

CONCLUSIONS

The composite inflammation and chronicity scores may already have direct utility in quantitatively assessing the disease stage. Further refinement and validation of RejectClass clusters are necessary to achieve more reliable and accurate phenotyping of rejection.

Rescue Allocation Modes in Eurotransplant Kidney Transplantation: Recipient Oriented Extended Allocation Versus Competitive Rescue Allocation-A Retrospective Multicenter Outcome Analysis

BACKGROUND

Whenever the kidney standard allocation (SA) algorithms according to the Eurotransplant (ET) Kidney Allocation System or the Eurotransplant Senior Program fail, rescue allocation (RA) is initiated. There are 2 procedurally different modes of RA: recipient oriented extended allocation (REAL) and competitive rescue allocation (CRA). The objective of this study was to evaluate the association of patient survival and graft failure with RA mode and whether or not it varied across the different ET countries.

METHODS

The ET database was retrospectively analyzed for donor and recipient clinical and demographic characteristics in association with graft outcomes of deceased donor renal transplantation (DDRT) across all ET countries and centers from 2014 to 2021 using Cox proportional hazards methods.

RESULTS

Seventeen thousand six hundred seventy-nine renal transplantations were included (SA 15 658 [89%], REAL 860 [4.9%], and CRA 1161 [6.6%]). In CRA, donors were older, cold ischemia times were longer, and HLA matches were worse in comparison with REAL and especially SA. Multivariable analyses showed comparable graft and recipient survival between SA and REAL; however, CRA was associated with shorter graft survival. Germany performed 76% of all DDRTs after REAL and CRA and the latter mode reduced waiting times by up to 2.9 y.

CONCLUSIONS

REAL and CRA are used differently in the ET countries according to national donor rates. Both RA schemes optimize graft utilization, lead to acceptable outcomes, and help to stabilize national DDRT programs, especially in Germany.

The Intersectoral Coordination Unit for the Sustainable Intensification of Peritoneal Dialysis in Schleswig-Holstein (SKIP-SH) cohort study

BACKGROUND

Peritoneal dialysis (PD) remains underutilised in Germany, prompting the initiation of the Sustainable Intensification of Peritoneal Dialysis in Schleswig-Holstein (SKIP-SH) project. The SKIP-SH cohort study aims to demonstrate the presumed benefits of PD, including enhanced quality of life and reduced healthcare personnel requirements, and to generate data to strengthen the use of PD.

METHODS

The prospective SKIP-SH cohort study recruits patients with advanced chronic kidney disease (CKD) and their caregivers. Comprehensive data, including demographic information, medical history, clinical course, laboratory data, and quality-of-life assessments, are collected. Additionally, biomaterials will be obtained. Primary study objectives are documenting the clinical course and complications, time on therapy for new dialysis patients, reasons influencing treatment modality choices, circumstances at the initiation of dialysis, and quality of life for patients with CKD and their caregivers. The collected biomaterials will serve as a basis for further translational research. Secondary objectives include identifying factors impacting disease-related quality of life, clinical complications, and therapy dropout, estimating ecological footprints, and evaluating healthcare costs and labour time for initiating and sustaining PD treatment.

DISCUSSION

PD is notably underutilised in Germany. The current therapy approach for advanced CKD often lacks emphasis on patient-focused care and quality-of-life considerations. Furthermore, adequate explorative research programs to improve our knowledge of mechanisms leading to disease progression and therapy failure in PD patients are scarce. The overarching goal of the SKIP-SH cohort study is to address the notably low PD prevalence in Germany whilst advocating for a shift towards patient-focused care, quality-of-life considerations, and robust translational research.

TRIAL REGISTRATION

This study was registered with the German trial registry (Deutsches Register klinischer Studien) on November 7, 2023, under trial number DRKS00032983.

The German Transplantation Registry Reveals Deficiencies in the Listing Process for Kidney Transplantation

Introduction

The time from dialysis onset to enrollment on the kidney waiting list (listing time) is a crucial step on the path to receiving a kidney allograft; however, this process has received very little research attention in the Eurotransplant (ET) area.

Methods

We retrospectively analyzed data from the German transplantation registry, including patients who were on the waiting list for a first kidney transplant in Germany between 2006 and 2016. Listing time was evaluated using a mixed linear model. The outcomes on the kidney waiting list were assessed using competing risk analyses.

Results

We assessed a total of 43,955 patients. Listing occurred at a higher pace in patients receiving living donor transplantations (median 0.4 years from dialysis onset) than in deceased donor transplantations (Eurotransplant Kidney Allocation System [ETKAS] 1.1 years, European Senior Program [ESP] 1.4 years, Acceptable Mismatch program 1.3 years), with 28.5% of living donor transplantations performed preemptively. There was only modest variation in listing time between the transplant centers. Patients with a history of viral infection, high immunization; hemodialysis patients; and patients with a higher body mass index (BMI) had a delayed listing process. Two of 3 patients listed in the ETKAS, excluding those with potential bonus points (pediatric, other organ transplantations), were eventually transplanted. Older patients, male patients, patients with blood type O, and patients with diabetic nephropathy as the underlying renal disease had the highest risk not to proceed to transplantation.

Conclusion

Although long waiting times remain the biggest hurdle for transplantation in Germany, there is ample room for improvement of the listing process.

Patient-focused outcomes after initiation of dialysis for ESRD: mortality, hospitalization and functional impairment

BACKGROUND

Outcome data regarding clinically relevant endpoints after starting dialysis for end-stage renal disease (ESRD) are sparse, and early events after starting dialysis are particularly underestimated. The aim of this study was to describe patient-focused outcomes in ESRD patients starting from first dialysis.

METHODS

The data basis for this retrospective observational study were anonymized healthcare data from Germany's largest statutory health insurer. We identified ESRD patients who initiated dialysis in 2017. Deaths, hospitalizations and occurrence of functional impairment within 4 years after starting dialysis were recorded starting from first treatment. Hazard ratios in dialysis patients compared with an age- and sex-matched reference population without dialysis were generated, stratified by age.

RESULTS

The dialysis cohort included 10 328 ESRD patients who started dialysis in 2017. First dialysis was performed in-hospital for 7324 patients (70.9%), and 865 of these died during the same hospitalization. One-year mortality for ESRD patients initiating dialysis was 33.8%. Functional impairment occurred in 27.1% of patients, while 82.8% of patients required hospitalization within 1 year. Hazard ratios of dialysis patients compared with the reference population for mortality, functional impairment and hospitalization at 1-year were 8.6, 4.3 and 6.2. Dialysis patients <50 years were disproportionately affected, with >40-fold increased risk of adverse events compared with their peers.

CONCLUSIONS

The emergence of morbidity and mortality after starting dialysis for ESRD is significant, especially in younger patients. Patients have a right to be informed about the prognosis associated with their condition.

The Tacrolimus Concentration/Dose Ratio Does Not Predict Early Complications After Kidney Transplantation

Early-on post kidney transplantation, there is a high risk of graft rejection and opportunistic viral infections. A low tacrolimus concentration/dose (C/D) ratio as a surrogate marker of fast tacrolimus metabolism has been established for risk stratification 3 months post-transplantation (M3). However, many adverse events occurring earlier might be missed, and stratification at 1 month post-transplantation (M1) has not been investigated. We retrospectively analyzed case data from 589 patients who had undergone kidney transplantation between 2011 and 2021 at three German transplant centers. Tacrolimus metabolism was estimated by use of the C/D ratio at M1, M3, M6, and M12. C/D ratios increased substantially during the year, particularly between M1 and M3. Many viral infections and most graft rejections occurred before M3. Neither at M1 nor at M3 was a low C/D ratio associated with susceptibility to BKV viremia or BKV nephritis. A low C/D ratio at M1 could not predict acute graft rejections or impaired kidney function, whereas at M3 it was significantly associated with subsequent rejections and impairment of kidney function. In summary, most rejections occur before M3, but a low C/D ratio at M1 does not identify patients at risk, limiting the predictive utility of this stratification approach.

Impact of first-line use of caplacizumab on treatment outcomes in immune thrombotic thrombocytopenic purpura

BACKGROUND

The von Willebrand factor-directed nanobody caplacizumab has greatly changed the treatment of immune thrombotic thrombocytopenic purpura (iTTP) in recent years. Data from randomized controlled trials established efficacy and safety.

OBJECTIVES

This study aims to address open questions regarding patient selection, tailoring of therapy duration, obstacles in prescribing caplacizumab in iTTP, effect on adjunct treatment, and outcomes in the real-world setting.

METHODS

We report retrospective, observational cohorts of 113 iTTP episodes treated with caplacizumab and 119 historical control episodes treated without caplacizumab. We aggregated data from the caplacizumab phase II/III trials and real-world data from France, the United Kingdom, Germany, and Austria (846 episodes, 396 treated with caplacizumab, and 450 historical controls).

RESULTS

Caplacizumab was efficacious in iTTP, independent of the timing of therapy initiation, but curtailed the time of active iTTP only when used in the first-line therapy within 72 hours after diagnosis and until at least partial ADAMTS13-activity remission. Aggregated data from multiple study populations showed that caplacizumab use resulted in significant absolute risk reduction of 2.87% for iTTP-related mortality (number needed to treat 35) and a relative risk reduction of 59%.

CONCLUSION

Caplacizumab should be used in first line and until ADAMTS13-remission, lowers iTTP-related mortality and refractoriness, and decreases the number of daily plasma exchange and hospital stay. This trial is registered at www.

CLINICALTRIALS

gov as #NCT04985318.

Epidemiology of haemophagocytic lymphohistiocytosis at the population level in Germany

We retrospectively analysed all German inpatient cases of haemophagocytic lymphohistiocytosis (HLH) from 2014 to 2020 to describe the epidemiology, clinical course, and underlying diseases of 4065 HLH patients. The age-standardized incidence rate of HLH in Germany was 0.52/100 000 people in 2014 and steadily increased by 10% per year to 0.97/100 000 in 2020 (mean 0.70/100 000). Inpatient deaths related to HLH increased from 0.84/1 000 000 people in 2014 to 2.32/1 000 000 people in 2020, caused by rising numbers of older HLH patients. Overall, HLH is more frequent than previously expected and incidence as well as HLH-related deaths increased significantly.

High Macrophage Densities in Native Kidney Biopsies Correlate With Renal Dysfunction and Promote ESRD

Introduction

Macrophages and monocytes are main players in innate immunity. The relevance of mononuclear phagocyte infiltrates on clinical outcomes remains to be determined in native kidney diseases.

Methods

Our cross-sectional study included 324 patients with diagnostic renal biopsies comprising 17 disease entities and normal renal tissues for comparison. All samples were stained for CD68⁺ macrophages. Selected groups were further subtyped for CD14⁺ monocytes and CD163⁺ alternatively activated macrophages. Using precise pixel-based digital measurements, we quantified cell densities as positively stained areas in renal cortex and medulla as well as whole renal tissue. Laboratory and clinical data of all cases at the time of biopsy and additional follow-up data in 158 cases were accessible.

Results

Biopsies with renal disease consistently revealed higher CD68⁺-macrophage densities and CD163⁺-macrophage densities in cortex and medulla compared to controls. High macrophage densities correlated with impaired renal function at biopsy and at follow-up in all diseases and in diseases analyzed separately. High cortical CD68⁺-macrophage densities preceded shorter renal survival, defined as requirement of permanent dialysis. CD14⁺ monocyte densities showed no difference compared to controls and did not correlate with renal function.

Conclusion

Precise quantification of macrophage densities in renal biopsies may contribute to risk stratification to identify patients with high risk for end-stage renal disease (ESRD) and might be a promising therapeutic target in renal disease.

Study protocol: the TRAnsplant BIOpsies (TRABIO) study - a prospective, observational, multicentre cohort study to assess the treatment of kidney graft rejections

INTRODUCTION

Despite continued efforts, long-term outcomes of kidney transplantation remain unsatisfactory. Kidney graft rejections are independent risk factors for graft failure. At the participating centres of the TRAnsplant BIOpsies study group, a common therapeutic standard has previously been defined for the treatment of graft rejections. The outcomes of this strategy will be assessed in a prospective, observational cohort study.

METHODS AND ANALYSIS

A total of 800 kidney transplantation patients will be enrolled who undergo a graft biopsy because of deteriorating kidney function. Patients will be stratified according to the Banff classification, and the influence of the treatment strategy on end points will be assessed using regression analysis. Primary end points will be all-cause mortality and graft survival. Secondary end points will be worsening of kidney function (≥30% decline of estimated Glomerular Filtration Rate [eGFR] or new-onset large proteinuria), recurrence of graft rejection and treatment response. Baseline data and detailed histopathology data will be entered into an electronic database on enrolment. During a first follow-up period (within 14 days) and subsequent yearly follow-ups (for 5 years), treatment strategies and clinical course will be recorded. Recruitment at the four participating centres started in September 2016. As of August 2020, 495 patients have been included.

ETHICS AND DISSEMINATION

Ethical approval for the study has been obtained from the ethics committee of Kiel (AZ B 278/16) and was confirmed by the committees of Munich, Mainz and Stuttgart. The results will be reported in a peer-reviewed journal, according to the Strengthening the Reporting of Observational Studies in Epidemiology criteria.

TRIAL REGISTRATION NUMBER

ISRCTN78772632; Pre-results.

MO444MACROPHAGE DENSITIES CORRELATE WITH LONG-TERM FUNCTION IN PAUCI-IMMUNE AND MEMBRANOUS GLOMERULONEPHRITIS AS WELL AS IN HYPERTENSIVE NEPHROPATHY

Background and Aims

Macrophages and monocytes are main players in innate immunity. In renal diseases, their role is poorly understood. Our multicentric cross-sectional study aimed to study the prevalence of macrophages and monocytes in various human native kidney diseases. For this, we used precise pixel-based digital quantification of their densities in renal biopsies and correlated our findings with clinical data.

Method

We included 324 patients, who underwent a diagnostic renal biopsy. Additional normal kidney samples from 16 tumour nephrectomies were used as controls. According to the diagnosed diseases, we established 17 patient groups. Biopsies were stained for CD68+-macrophages using automated immunohistochemistry (Ventana Ultra) and selected groups were further subtyped for CD14+-monocytes and CD163+-M2-macrophages (67 cases, pauci-immune glomerulonephritis (PIGN), IgA-nephropathy (IgAN) and control samples). Digitized sections (Leica) were analysed using the open-source software QuPath to quantify cell densities (positively stained areas displayed as percentages of ROI) in renal cortex, medulla and extrarenal tissue, respectively. Detailed clinical and laboratory data at timepoint of biopsy were available for all patients. Additional data for follow-up were achievable in 158 cases.

Results

Renal disease samples presented higher mean macrophage densities compared to control cases (CD68: cortex 1.2 vs. 0.2%, p&lt;0.001, medulla 0.8 vs. 0.04%, p&lt;0.001; CD163: cortex 3.2 vs. 0.5%, p&lt;0.001, medulla 2.3 vs. 0.6%, p&lt;0.05), but CD14+-density did not differ between patients and control samples. The highest cortical CD68+-density occurred in PIGN (1.98%) and in medulla in ascending infections (1.86%). The lowest cortical CD68+-densities were measured in thin basal membrane syndrome / Alport-syndrome (0.56%) and in medulla in immunotactoid and fibrillary glomerulopathy (0.26%). Chronic kidney disease displayed lower percentages of CD68+-densities (cortex: 1.15%; medulla: 0.49%) compared to acute kidney injury (cortex: 1.84%, p&lt;0.001; medulla: 1.08%, p&lt;0.001) and acute on chronic kidney injury (cortex: 1.81%, p&lt;0.001; medulla: 1.43%, p&lt;0.001). We detected a correlation of CD68+- and CD163+-infiltration with kidney function (eGFR) in cortex and medulla at the time of biopsy (CD68: r=-0.51 for cortex, r=-0.60 for medulla; CD163: r=-0.71 for cortex, r=-0.73 for medulla; p&lt;0.001) and follow up (CD68: r=-0.41 for cortex, r=-0.34 for medulla, p&lt;0.001; CD163: r=-0.46 for cortex, r=-0.50 for medulla, p&lt;0.05). Older patients (&gt;64 years) showed a higher medullary M2-infiltration (1.81% vs. 4.34%, p&lt;0.005). The eGFR at the time of biopsy inversely correlated (p&lt;0.05) with cortical CD68+-density in IgAN (r=-0.39), PIGN (r=-0.53), membranous glomerulonephritis (MGN; r=-0.70), focal segmental glomerulonephritis (r=-0.63), and hypertensive nephropathy (HNP; r=-0.44). At follow-up, this correlation (p&lt;0.05) was still present in PIGN (r=-0.43), MGN (r=-0.58), and HNP (r=-0.77). In PIGN, cortical CD163+-density and eGFR were associated (p&lt;0.001) at timepoint of biopsy (r=-0.51) and follow-up (r=-0.51). Particularly, cANCA-vasculitis showed a strong correlation between eGFR and cortical CD68+- as well as CD163+-densities at time of biopsy (CD68: r=-0.78; CD163: r=-0.75, p&lt;0.001) and also for follow-up (CD68: r=-0.48; CD163: r=-0.68, p&lt;0.05).

Conclusion

Macrophages may promote progression of human renal diseases, whereas monocytes do not correlate with eGFR-decline. Especially, in cANCA- vasculitis CD163+- infiltration is associated with renal outcome. Additional studies are needed to investigate, whether macrophages can serve as predictive markers or therapeutical targets in native renal diseases.

A surprising foreign body abscess

An abscess is a common complication after surgical interventions. Furthermore, abscesses of different genesis often occur under immunosuppression. In the case of a kidney transplant patient described here, however, the cause of an abscess-like mass in the abdomen was an unusual one, the etiology of which we could only clarify after surgical removal.

Evaluation of underidentification of potential organ donors in German hospitals

Background

Since 2010, the number of organ donations in Germany has decreased by one third, mostly due to undetected organ donors. It is unclear, how the undetected potential donor pool is distributed among the different German hospital categories (A = university hospital, B = hospitals with neurosurgery, C = hospitals without neurosurgery) and region types.

Methods

We performed a nationwide secondary data analysis of all German inpatient cases of the year 2016 (n = 20,063,689). All fatalities were regarded as potential organ donors, in which primary or secondary brain damage was encoded and organ donation was not excluded by a contraindication or a lack of ventilation therapy.

Results

In 2016, 28,087 potential organ donors were identified. Thereof 21% were found in category A, 28% in category B and 42% in category C hospitals. The contact rate (= organ donation related contacts/ potential organ donors) and realization rate (= realized organ donations/ potential organ donors) of category A, B and C hospitals was 10.6% and 4.6%, 10.9% and 4.8% and 6.0% and 1.7%, respectively. 58.2% of the donor potential of category C hospitals was found in the largest quartile of category C hospitals. 51% (n = 14,436) of the potential organ donors were treated in hospitals in agglomeration areas, 28% (n = 7,909) in urban areas and 21% (n = 5,742) in rural areas. The contact- and realization rate did not significantly differ between these areas.

Conclusions

The largest proportion of potential organ donors and the lowest realization rate are found in category C hospitals. Reporting and donation practice do not differ between urban and rural regions.

Strategies for Improving Influenza Vaccination Rates in Patients with Chronic Renal Disease

BACKGROUND

The influenza vaccination rate among older and chronically ill patients in Germany has declined in the past decade in spite of vaccination campaigns.

METHODS

The influenza vaccination rate among persons with chronic renal disease was studied with the aid of billing data from various Associations of Statutory Health Insurance Physicians (Kassenärztliche Vereinigungen, ASHIPs) in Germany. It was tested in a randomized controlled trial whether a written vaccination appeal, sent by physicians to patients, led to an increase in the vaccination rate. It was tested in a further such trial whether the vaccination rate among patients with renal disease could be improved by an appeal for vaccination that was sent by the ASHIPs to the treating nephrologists. Finally, it was also tested in a prospective interventional study whether the vaccination rate could be improved by an appeal for vaccination sent by a health- insurance carrier directly to the patients.

RESULTS

In 2012-2017, the vaccination rate among persons with chronically impaired renal function ranged from 41.1% to 46.9%; it ranged from 31.7% to 33.7% in kidney transplant recipients and from 42.7% to 44.7% in dialysis patients. An appeal for vaccination that was sent from physicians to patients raised the vaccination rate by 8.3% in the intervention group compared to the control group (p = 0.03; number needed to treat [NNT]: 13). On the other hand, an appeal for vaccination that was sent to the nephrologists lowered the vaccination rate by 0.8% in the intervention group compared to the control group. Finally, an appeal for vaccination that was sent by the health-insurance fund to the patients raised the vaccination rate by 3.2% (p<0.001; NNT: 32).

CONCLUSION

Fewer than half of all patients with chronic renal failure in Germany are vaccinated against influenza. The vaccination rate was found to be increased only after an appeal for vaccination that was sent directly to the patients. A letter sent to the treating physicians had no positive effect at all.

The work and training situation for young physicians undergoing specialty training in gynecology and obstetrics in Germany: an assessment of the status quo

Purpose

General conditions in the health-care system in Germany have changed dramatically in recent years. Factors affecting this include above all demographic change, rapid developments in diagnostic and therapeutic options, and the application of economic criteria to the health-care sector. This study aimed to establish the current status quo regarding conditions of work and training for young doctors in gynecology and obstetrics, analyze stress factors, and suggest potential improvements.

Methods

Between October 2015 and March 2016, a web-based survey was carried out among residents and members of the German Society for Gynecology and Obstetrics. The electronic questionnaire comprised 65 items on seven topics. Part of the survey included the short version of a validated model of professional gratification crises for analyzing psychosocial work-related stress.

Results

The analysis included a total of 391 complete datasets. Considerable negative findings in relation to psychosocial work pressure, time and organizational factors, quality of specialty training, and compatibility between work and family life and work and academic tasks were detected. A high level of psychosocial work pressure is associated with more frequent job changes, reduced working hours, poorer health among physicians, and a lower subjectively assessed quality of care.

Conclusions

Greater efforts are needed from all the participants involved in patient care to achieve high-quality training and working conditions that allow physicians to work in a healthy and effective way. These aspects are all prerequisites for sustainably maximizing the resource “physician” and for ensuring high-quality patient care.

Cre recombinase toxicity in podocytes: a novel genetic model for FSGS in adolescent mice

Here, we show that inducible overexpression of Cre recombinase in glomerular podocytes but not in parietal epithelial cells may trigger focal segmental glomerulosclerosis (FSGS) in juvenile transgenic homocygous Pod-rtTA/LC1 mice. Administration of doxycycline shortly after birth, but not at any other time point later in life, resulted in podocyte injury and development of classical FSGS lesions in these mice. Sclerotic lesions were formed as soon as 3 wk of age, and FSGS progressed with low variability until 13 wk of age. In addition, our experiments identified Cre toxicity as a potentially relevant limitation for studies in podocytes of transgenic animals. In summary, our study establishes a novel genetic model for FSGS in mice, which exhibits low variability and manifests already at a young age.

Carrier-Transport Study of Gallium Arsenide Hillock Defects

Single-crystalline gallium arsenide (GaAs) grown by various techniques can exhibit hillock defects on the surface when sub-optimal growth conditions are employed. The defects act as nonradiative recombination centers and limit solar cell performance. In this paper, we applied near-field transport imaging to study hillock defects in a GaAs thin film. On the same defects, we also performed near-field cathodoluminescence, standard cathodoluminescence, electron-backscattered diffraction, transmission electron microscopy, and energy-dispersive X-ray spectrometry. We found that the luminescence intensity around the hillock area is two orders of magnitude lower than on the area without hillock defects in the millimeter region, and the excess carrier diffusion length is degraded by at least a factor of five with significant local variation. The optical and transport properties are affected over a significantly larger region than the observed topography and crystallographic and chemical compositions associated with the defect.

Inverse correlation between vascular endothelial growth factor back-filtration and capillary filtration pressures

Background

Vascular endothelial growth factor A (VEGF) is an essential growth factor during glomerular development and postnatal homeostasis. VEGF is secreted in high amounts by podocytes into the primary urine, back-filtered across the glomerular capillary wall to act on endothelial cells. So far it has been assumed that VEGF back-filtration is driven at a constant rate exclusively by diffusion.

Methods

In the present work, glomerular VEGF back-filtration was investigated in vivo using a novel extended model based on endothelial fenestrations as surrogate marker for local VEGF concentrations. Single nephron glomerular filtration rate (SNGFR) and/or local filtration flux were manipulated by partial renal mass ablation, tubular ablation, and in transgenic mouse models of systemic or podocytic VEGF overexpression or reduction.

Results

Our study shows positive correlations between VEGF back-filtration and SNGFR as well as effective filtration rate under physiological conditions along individual glomerular capillaries in rodents and humans.

Conclusion

Our results suggest that an additional force drives VEGF back-filtration, potentially regulated by SNGFR.

Decline in Organ Donation in Germany

BACKGROUND

The annual number of post-mortem organ donations in Germany has declined by more than 30% since 2010. The causes of this development have not yet been adequately determined.

METHODS

All patients hospitalized in Germany between 2010 and 2015 (112 172 869 hospitalizations in total) were included in this nationwide secondary analysis. Among the deceased patients we identified those who had died in the presence of a brain damage and for whom organ donation was not excluded either by a medical contraindication or by the patient's not having been artificially ventilated. The analysis was also conducted separately for six German university hospitals.

RESULTS

Over the period 2010-2015, the number of potential organ donors per year in Germany rose by 13.9%, from 23 937 to 27 258. This development was due to an increase in the number of deaths with severe brain damage as well as an increase in the percentage of patients who were treated with invasive ventilation before death. The contact quotient, i.e., the percentage of potential donors for whom contact was made with the German Foundation for Organ Transplantation (Deutsche Stiftung Organtransplantation, DSO) fell over this period from 11.4% to 8.2%. At the same time, the realization quotient (the percentage of potential donors who became actual donors) fell from 5.4% to 3.2%, and the conversion quotient (the percentage of potential donors for whom contact was made who became actual donors) fell from 47% to 39.1%. From 2010 to 2012, the falling realization quotient was accounted for mainly by the falling conversion quotient; from 2012 to 2015, it was accounted for mainly by the falling contact quotient. The contact and realization quotients among the six university hospitals studied differed markedly (by factors of 17.5 and 23.3, respectively), while the conversion quotients differed only minimally (by a factor of 1.3).

CONCLUSION

The decline in post-mortem organ donation is due to a deficiency in the recognition and reporting of potential organ donors in hospital. If this process were better supported on the organizational and political level, far more organs could be transplanted.

[Work and Training of Young Doctors in Germany - a Comprehensive Analysis of Survey Results from Six Disciplines]

OBJECTIVE

The working and training conditions of young physicians in Germany have changed over the last few years, as a result of far-reaching changes in the healthcare system. Therefore, Germany-wide surveys among young physicians of several disciplines were evaluated in a pooled analysis, in order to obtain a current interdisciplinary impression of conflicts in their daily work.

MATERIAL AND METHODS

Data from web-based surveys from residents training in six disciplines were analyzed together retrospectively. One focus was a gratification crises model for the assessment of psychosocial workload.

RESULTS

Data on 4041 participants were evaluated. In day-to-day work, young physicians were burdened with a high proportion of tasks that were not directly medical. Instruments of good subspecialty training, such as training contracts, curricula and regular feedback were associated with a lower psychosocial workload, which was generally significant among the participants. An economic influence on medical-professional decisions was subjectively clearly present among the participants.

CONCLUSION

Many young doctors find the current work and training conditions in the medical work environment unsatisfactory. This might have consequences not only for the doctors themselves, but also for the patients they care for. A healthy work environment with health professionals in good health is therefore crucial and should be in everyone's interest.

Analysis of the Eurotransplant Kidney Allocation Algorithm: How Should We Balance Utility and Equity?

BACKGROUND

Since 2014, expected graft and recipient survival are matched by the U.S. kidney allocation system to improve organ utility. This mechanism is based on the kidney donor profile index (KDPI) and the estimated posttransplant survival score (EPTS). Here we analyzed 1. the transferability of these scores into the Eurotransplant (ET) region and 2. the extent to which the ET kidney allocation algorithm promotes utility.

METHODS

We studied data of 262 kidney transplantations performed at the University Hospital Kiel between 2000 and 2009 (median follow-up, 9.94 years).

RESULTS

Multivariable Cox regression analysis revealed that only the variables donor age of the KDPI and recipient's age of the EPTS have a significant value as predictors of posttransplant graft and recipient survival. The other variables showed no additional predictive value. Analyzing all kidneys allocated in the ET kidney allocation system and the European Senior Program, we found that donor and recipient's age and KDPI and EPTS were weakly correlated (r_age-age = 0.5, P < .001; r_KDPI-EPTS = 0.4, P < .01). If both programs were analyzed separately, no correlation between donor and recipient's age and between KDPI and EPTS was detected.

CONCLUSION

The ET kidney allocation algorithm poorly matched predicted graft and recipient survival at our center. A better age-matching may improve organ utility.

[Work and Training Conditions of Young German Physicians in Internal Medicine - Results of a Second Nationwide Survey by Young Internists from the German Society of Internal Medicine and the German Professional Association of Internists.]

BACKGROUND

 Medical specialty training is the basis for career development of young internists and it is vital for the delivery of high-quality medical care. In 2014 the young internists of two professional bodies in Germany conducted a survey among their young members and described major factors influencing training and working conditions. We present the results of a follow-up survey to describe changes of these factors over time. An additional focus is set on the difficulties of balancing medical career and family.

METHODS

 In the end of 2016 we conducted an online-based survey of all members in training of the German Society of Internal Medicine (DGIM) and the Professional Association of German Internists (BDI). The questionnaire used in the 2014 survey was modified and items investigating the balance between career and family were added.

RESULTS

 A total of 1587 questionnaires were returned and analysed. Mayor findings did not change over time. Psychosocial strain remains very high among medical trainees in internal medicine. A structured training curriculum and meaningful feedback are associated with lower psychosocial strain and higher work satisfaction. Internists - and here especially women - with children experience the daily balance of medical career and family as extremely challenging.

CONCLUSION

 These results demonstrate that there is still a serious need for adjusting training and working conditions of young internists in Germany. Especially the role and increasing importance of female physicians has to be recognized by enabling a successful integration of medical career and family.

Five-Year Stability Study of Free and Total Prostate-Specific Antigen Concentrations in Serum Specimens Collected and Stored at – 70°C or Less

The stability of total (t) and free (f) prostate-specific antigen (PSA) in male serum specimens stored at –70°C or lower temperature for 4.7 to 4.9 years was studied. Until now, the stability of these analytes in serum has not been evaluated systematically beyond 2 years of storage at –70°C. Aliquots of frozen serum were thawed in 2001 and 2006 and assayed for tPSA and fPSA using a Dade Behring Dimension(r) RxL analyzer and reagents. tPSA values ranged from 0.07 to 69.94 and 0.00 to 69.83 ng/mL in 2001 and 2006, respectively, whereas fPSA values for the tested specimens ranged from 0.02 to 5.72 and 0.00 to 5.92, respectively. Deming regression analyses showed agreement in assay values over time as tPSA values yielded a slope of 1.0112 and a y-intercept of 0.0195; fPSA values produced a slope 1.0538 and a y-intercept of –0.0442; f/tPSA values yielded a slope of 0.9631 and a y-intercept of 0.1195. A Bland-Altman analysis of the data demonstrated analyte and ratio stability over this time period. We conclude that serum, when collected properly and stored at –70°C or lower temperature, may be used for tPSA and fPSA clinical studies for at least 5 years after collection.

Radial access protects from contrast media induced nephropathy after cardiac catheterization procedures

OBJECTIVES

To assess, whether cardiac catheterization via radial access prevents contrast-induced nephropathy.

BACKGROUND

Contrast-induced nephropathy (CIN) is a major clinical problem which accounts for more than 10% of acute kidney injury cases in hospitalized patients. Protective measures such as the infusion of isotonic saline solution or acetylcysteine have not consistently been proven to prevent acute kidney injury (AKI). However, there is growing evidence that radial access for coronary angiography and coronary intervention is associated with a lower incidence of AKI compared to femoral access.

METHODS AND RESULTS

In a retrospective monocentric analysis, 2937 patients that had undergone cardiac catheterization were examined. Up to 2013, coronary intervention was performed primarily via the femoral artery in our hospital; thereafter, interventions were primarily done via the radial artery. In the cohort under study, 1141 patients had received catheterization using the radial access while 1796 were examined via the femoral artery. No significant differences were found in the two groups regarding the amount of iodinated contrast medium applied [femoral group: 180 (120-260) ml; radial group: 180 (120-250) ml; P = 0.438]. A total of 400 (13.6%) patients developed acute kidney injury (AKI) after cardiac catheterization (85.3% AKI stage 1; 12.8% AKI stage 2; 2% AKI stage 3). AKI was significantly less frequent in patients that had received radial access compared to patients with femoral access (10.1 vs. 15.9%, P < 0.001). Multivariate regression analysis showed that patient age (1.03/year; 95% CI 1.02-1.04/year; P < 0.001), the amount of contrast media applied (OR 1.003/ml; 95% CI 1.002-1.004/ml; P < 0.001), acute coronary syndrome (OR 2.01, 95% CI 1.52-2.66; P < 0.001), CKD (OR 1.62, 95% CI 1.50-1.70; P < 0.001), pre-existing heart failure (OR 1.27, 95% CI 1.00-1.42 P = 0.007), previous myocardial infarction (OR 1.34, 95% CI 1.15-1.49; P = 0.001), diabetes (OR 1.25, 95% CI 1.04-1.41; P = 0.020) and serum creatinine before the procedure (1.45/mg/dl; 95% CI 1.24-1.69/mg/dl; P < 0.001) were important risk factors for the occurrence of AKI. Our analysis points to a significant risk reduction using radial access (OR 0.65; 95% CI 0.51-0.83; P < 0.001). Interestingly, this reduction in risk was also evident in patients with CKD (OR 0.59; 95% CI 0.41-0.87; P = 0.007). The superiority of radial access was particularly obvious in the subgroup of patients with acute coronary syndrome (13.1% AKI in the radial access group vs. 23.6% AKI in the femoral access group, OR 0.52; 95% CI 0.34-0.81; P = 0.003).

CONCLUSION

Our study shows that cardiac catheterization using radial access bears significantly lower risk of AKI than cardiac catheterization via femoral access. The advantage of radial access in acute coronary syndrome regarding morbidity and mortality could partly be explained by the here demonstrated reduced risk for AKI. Thus, radial access should be preferred in patients at risk for AKI.

Late conversion from tacrolimus to a belatacept-based immuno-suppression regime in kidney transplant recipients improves renal function, acid-base derangement and mineral-bone metabolism

BACKGROUND

Calcineurin inhibitor (CNI)-induced nephrotoxicity and chronic graft dysfunction with deteriorating glomerular filtration rate (GFR) are common problems of kidney transplant recipients. The aim of this study was to analyze the role of belatacept as a rescue therapy in these patients.

METHODS

In this retrospective, observational study we investigated 20 patients (10 females, 10 males) who were switched from a CNI (tacrolimus) to a belatacept-based immunosuppression because of CNI intolerance or marginal transplant function. Patient follow-up was 12 months.

RESULTS

Patients were converted to belatacept in mean 28.8 months after transplantation. Reasons for conversion were CNI intolerance (14 patients) or marginal transplant function (6 patients). Mean estimated GFR (eGFR) before conversion was 22.2 ± 9.4 ml/min at baseline and improved significantly to 28.3 ± 10.1 ml/min at 4 weeks and to 32.1 ± 12.6 ml/min at 12 months after conversion. Serum bicarbonate significantly increased from 24.4 ± 3.2 mmol/l at baseline to 28.7 ± 2.6 mmol/l after 12 months. Conversion to belatacept decreased parathyroid hormone and phosphate concentrations significantly, whereas albumin levels significantly increased. In 6 cases an acute rejection preceded clinically relevant CNI toxicity; only two patients suffered from an acute rejection after conversion. Belatacept was well tolerated and there was no increase in infectious or malignant side effects.

CONCLUSION

A late conversion from a tacrolimus-based immunosuppression to belatacept is safe, effective and significantly improves renal function in kidney transplant recipients. Additionally, the conversion to belatacept has a beneficial impact on acid-base balance, mineral-bone and protein metabolism, independently of eGFR.

[Work and training conditions of young German physicians in internal medicine. Results of a nationwide survey by young internists from the German Society of Internal Medicine and the German Professional Association of Internists]

BACKGROUND

Major transformations within the German healthcare system (e. g. implementation of the G-DRG system, growing focus on economic aspects, demographic changes) led to changes of work and training conditions of young internists and to criticism and dissatisfaction. So far, there is a lack of up-to-date and nationwide data analyzing these issues with focus on economic pressure and psychosocial strain.

METHODS

The young internists of the two professional bodies conducted an online-based survey addressing all their members in training. The questionnaire covers five central areas of conflict. Furthermore, the model of effort-reward-imbalance (ERI) was applied to measure psychosocial strain at work.

RESULTS

1696 internists in training participated in the survey. Workdays characterized by high pace and workload do not leave much room for professional training as well as for family and research friendly working conditions. A relevant part of the affected physicians draws or at least considers personal consequences. Economical pressure is clearly noticeable. Psychosocial strain among the questioned internists is very high and conveys a risk for physicians' health and patients' quality of care.

CONCLUSION

Adjustments of working and training conditions in internal medicine are necessary to preserve physicians health, high-quality medical treatment and to ensure an attractive working environment.

Beam transport and space charge compensation strategies (invited)

The transport of intense ion beams is affected by the collective behavior of this kind of multi-particle and multi-species system. The space charge expressed by the generalized perveance dominates the dynamical process of thermalisation, which leads to emittance growth. To prevent changes of intrinsic beam properties and to reduce the intensity dependent focusing forces, space charge compensation seems to be an adequate solution. In the case of positively charged ion beams, electrons produced by residual gas ionization and secondary electrons provide the space charge compensation. The influence of the compensation particles on the beam transport and the local degree of space charge compensation is given by different beam properties as well as the ion beam optics. Especially for highly charged ion beams, space charge compensation in combination with poor vacuum conditions leads to recombination processes and therefore increased beam losses. Strategies for providing a compensation-electron reservoir at very low residual gas pressures will be discussed.

The evolution of blood pressure and the rise of mankind

Why is it that only human beings continuously perform acts of heroism? Looking back at our evolutionary history can offer us some potentially useful insight. This review highlights some of the major steps in our evolution-more specifically, the evolution of high blood pressure. When we were fish, the first kidney was developed to create a standardized internal 'milieu' preserving the primordial sea within us. When we conquered land as amphibians, the evolution of the lung required a low systemic blood pressure, which explains why early land vertebrates (amphibians, reptiles) are such low performers. Gaining independence from water required the evolution of an impermeable skin and a water-retaining kidney. The latter was accomplished twice with two different solutions in the two major branches of vertebrate evolution: mammals excrete nitrogenous waste products as urea, which can be utilized by the kidney as an osmotic agent to produce more concentrated urine. Dinosaurs and birds have a distinct nitrogen metabolism and excrete nitrogen as water-insoluble uric acid-therefore, their kidneys cannot use urea to concentrate as well. Instead, some birds have developed the capability to reabsorb water from their cloacae. The convergent development of a separate small circulation of the lung in mammals and birds allowed for the evolution of 'high blood-pressure animals' with better capillarization of the peripheral tissues allowing high endurance performance. Finally, we investigate why mankind outperforms any other mammal on earth and why, to this day, we continue to perform acts of heroism on our eternal quest for personal bliss.

Evolution of Epilayer Tilt in InGaAs Metamorphic Buffer Layers Grown by HVPE

Tilt behavior in InxGa1-xAs metamorphic buffer layers (MBLs) grown by hydride vapor phase epitaxy (HVPE) was measured by high resolution x-ray diffraction (HRXRD). Step- and continuously-graded structures were grown on exactly (001) oriented GaAs substrates as well as on substrates with a miscut of 40→ (111)B of (001). Growth temperature and final In composition were varied as well. HRXRD Ω-F mapping was employed to independently resolve both the magnitude and direction of tilt as a function of depth throughout each structure. Tilt azimuth was initially random in growths on nominally (001) oriented substrates and changed as grading continued, moving closer to [110]. Tilt magnitude increased more linearly and to larger values as a function of xInAs in the step-graded vs. continuously graded samples. MBLs grown on 40miscut substrates tilted in the opposite direction of the miscut surface normal, and the tilt magnitude for a given xInAs was greater than for planar samples. When the tilt vectors of the miscut samples were resolved along the orthogonal [-110] and [110] directions it was found that the tilt was much stronger along the direction that the miscut was aligned, or [-110]. Tilt in the planar samples increased monotonically and to larger magnitudes along [110] compared with [-110]. The behavior on miscut samples can be attributed to the preferential generation of dislocations on slip systems which experience a larger resolved shear stress due to the miscut [1]. The tilt anisotropy in planar samples can be attributed to the fact that dislocation cores and core energies in III-V semiconductors are also anisotropic [2]. Dislocation nucleation along [110] has a higher activation energy, so a larger proportion of dislocations is likely generated by multiplication sources, creating arrays of dislocations possessing the same burgers vector. Dislocation distributions in samples grown at high temperature were found to be more uniform, overcoming these barriers.

Cardiac dose sparing and avoidance techniques in breast cancer radiotherapy

Breast cancer radiotherapy represents an essential component in the overall management of both early stage and locally advanced breast cancer. As the number of breast cancer survivors has increased, chronic sequelae of breast cancer radiotherapy become more important. While recently published data suggest a potential for an increase in cardiac events with radiotherapy, these studies do not consider the impact of newer radiotherapy techniques commonly utilized. Therefore, the purpose of this review is to evaluate cardiac dose sparing techniques in breast cancer radiotherapy. Current options for cardiac protection/avoidance include (1) maneuvers that displace the heart from the field such as coordinating the breathing cycle or through prone patient positioning, (2) technological advances such as intensity modulated radiation therapy (IMRT) or proton beam therapy (PBT), and (3) techniques that treat a smaller volume around the lumpectomy cavity such as accelerated partial breast irradiation (APBI), or intraoperative radiotherapy (IORT). While these techniques have shown promise dosimetrically, limited data on late cardiac events exist due to the difficulties of long-term follow up. Future studies are required to validate the efficacy of cardiac dose sparing techniques and may use surrogates for cardiac events such as biomarkers or perfusion imaging.

The regenerative potential of parietal epithelial cells in adult mice

Previously, we showed that some podocytes in juvenile mice are recruited from cells lining Bowman's capsule, suggesting that parietal epithelial cells (PECs) are a progenitor cell population for podocytes. To investigate whether PECs also replenish podocytes in adult mice, PECs were genetically labeled in an irreversible fashion in 5-week-old mice. No significant increase in labeled podocytes was observed, even after 18 months. To accelerate a potential regenerative mechanism, progressive glomerular hypertrophy was induced by progressive partial nephrectomies. Again, no significant podocyte replenishment was observed. Rather, labeled PECs exclusively invaded segments of the tuft affected by glomerulosclerosis, consistent with our previous findings. We next reassessed PEC recruitment in juvenile mice using a different reporter mouse and confirmed significant recruitment of labeled PECs onto the glomerular tuft. Moreover, some labeled cells on Bowman's capsule expressed podocyte markers, and cells on Bowman's capsule were also directly labeled in juvenile podocyte-specific Pod-rtTA transgenic mice. In 6-week-old mice, however, cells on Bowman's capsule no longer expressed podocyte-specific markers. Similarly, in human kidneys, some cells on Bowman's capsule expressed the podocyte marker synaptopodin from 2 weeks to 2 years of age but not at 7 years of age. In summary, podocyte regeneration from PECs could not be detected in aging mice or models of glomerular hypertrophy. We propose that a small fraction of committed podocytes reside on Bowman's capsule close to the vascular stalk and are recruited onto the glomerular tuft during infancy to adolescence in mice and humans.

Origin of parietal podocytes in atubular glomeruli mapped by lineage tracing

Parietal podocytes are fully differentiated podocytes lining Bowman's capsule where normally only parietal epithelial cells (PECs) are found. Parietal podocytes form throughout life and are regularly observed in human biopsies, particularly in atubular glomeruli of diseased kidneys; however, the origin of parietal podocytes is unresolved. To assess the capacity of PECs to transdifferentiate into parietal podocytes, we developed and characterized a novel method for creating atubular glomeruli by electrocoagulation of the renal cortex in mice. Electrocoagulation produced multiple atubular glomeruli containing PECs as well as parietal podocytes that projected from the vascular pole and lined Bowman's capsule. Notably, induction of cell death was evident in some PECs. In contrast, Bowman's capsules of control animals and normal glomeruli of electrocoagulated kidneys rarely contained podocytes. PECs and podocytes were traced by inducible and irreversible genetic tagging using triple transgenic mice (PEC- or Pod-rtTA/LC1/R26R). Examination of serial cryosections indicated that visceral podocytes migrated onto Bowman's capsule via the vascular stalk; direct transdifferentiation from PECs to podocytes was not observed. Similar results were obtained in a unilateral ureter obstruction model and in human diseased kidney biopsies, in which overlap of PEC- or podocyte-specific antibody staining indicative of gradual differentiation did not occur. These results suggest that induction of atubular glomeruli leads to ablation of PECs and subsequent migration of visceral podocytes onto Bowman's capsule, rather than transdifferentiation from PECs to parietal podocytes.

[Knowledge of laws by students with hearing impairment: results from the GINKO-project]

Legislation for people with disabilities has also changed due to other changes in the law, especially due to the recent ratification of the UN Convention on the Rights of Persons with Disabilities. These laws, in particular the UN Convention on the Rights of Persons with Disabilities, with its inclusion of the right to equitable and universal access to education for people with disabilities and their implementation, are of central importance for students who are impaired. As part of the GINKO (the legislative effect laws have on the professional integration of those who are hard of hearing, people who have gone deaf and those who are deaf through communication and organization; promotion: BMAS) project, the following questions were also brought up for discussion and were investigated: to what extent hearing-impaired students are aware of legislation that benefits them, whether these laws will be implemented, and what factors have an impact on this legal knowledge or its implementation. Overall, 4,825 handicapped individuals with hearing impairments - including n=166 students - took part in the survey. The results of the evaluation of the group of hearing-impaired students indicate that many of them are not informed about laws important to them. It was also found that the knowledge of a law cannot be equated with its implementation. This survey also resulted in a resolve for the future, to demand information about legal options be reinforced, and to adjust this information to fit the needs of specific target groups, e.g. this information could be disseminated through sign language films. On the other hand, these results also apply to higher education, for these institutions to create learning conditions where existing regulatory design options for students with disabilities are implemented, thereby affording students an equal opportunity to participate in higher education.