Mutagenesis and polyploidization for creation of new genetic variability of Hydrangea macrophylla

Für die Erweiterung der Zuchtmethodik bei Hydrangea macrophylla gelangten Methoden der induzierten Mutagenese und Polyploidisierung zur Anwendung. Für die Mutagenese wurden In-vitro-Nodienexplantate der Sorte Blaumeise mit Röntgenstrahlung mit den Dosen 5, 10, 15, 20 und 30 Gy behandelt. Die letale Dosis von 50% lag zwischen 20 und 30 Gy. Nach Gewächshausüberführung zeigten die bestrahlten Pflanzen veränderte Merkmale wie Wuchsdepressionen, deformierte Blütenstände und schwarze Stiele. Die Polyploidisierung wurde ebenfalls in vitro an Nodienexplantaten durchgeführt. Ausgangsmaterial waren die diploiden Sorten Adria und Libelle sowie die triploiden Sorten Blaumeise und Nachtigall. Kolchizin und Trifluralin dienten als chemische Agenzien zur Hemmung der Mitose. Nach Kolchizinbehandlung wurden nur vier Ploidiechimären gefunden. Trifluralin war weitaus effektiver. Bereits eine Konzentration von 0,001% Trifluralin induzierte die Bildung polyploidisierter Pflanzen. Hexaploide Pflanzen der Sorten Blaumeise und Nachtigall zeigten eine sehr starke Wuchsdepres­sion und Blattdeformierungen, die Blütenbildung war gestört. Dagegen waren tetraploide Pflanzen der Sorten Adria und Libelle attraktiv wie ihre diploiden Ausgangsformen. Die Flowzytometrie ermöglichte eine schnelle Feststellung des Ploidieniveaus und nach Fluoreszenz-in-situ-Hybridisierung mit Gensequenzen der 5S und 18/25S rDNA erfolgte die Bestimmung der Karyo­typen. Beide ribosomale Gensequenzen waren jeweils nur ein Mal im haploiden Genom auf unterschiedlichen Chromosomen lokalisiert. Die Bedeutung der Methoden Mutagenese und Polyploidisierung zur Schaffung von Prebreeding-Material wird diskutiert. Insbesondere der Einsatz von tetraploiden Hortensien im Zuchtprozess scheint ein aussichtsreicher Beitrag zur Erweiterung des bestehenden Sortenspektrums zu sein.    The suitability of induced mutagenesis and polyploidization of Hydrangea macrophylla to be incorporated in breeding programs was investigated. For mutagenesis nodal explants in vitro of variety Blaumeise were irra­diated with X-rays (5, 10, 20 and 30 Gy). The lethal dose of 50% was between 20 and 30 Gy. Irradiated plants were transferred to the greenhouse. New phenotypic traits like dwarfism, deformed leaves or black stems were observed. Polyploidization was carried out on nodal explants in vitro, too. Plant material was from the diploid varieties Adria and Libelle as well as from the triploid varieties Blaumeise and Nachtigall. For mitosis inhibition colchicine and trifluralin were used. After treatment with colchicine only four ploidy chimeric plants were found. The effectiveness of trifluralin was much better. Already after treatment with 0.001% trifluralin polyploidized plants were received. Hexaploid plants showed a strong dwarfism and deformed leaves. By contrast, tetraploid plants were attractive like the diploid origins. The flow cytometry enabled rapid ploidy estimation and after the fluorescence in situ hybridization with gene sequences of 5S and 18/25S rDNA the karyotypes were characterized. Each ribosomal DNA sequence used was localized one time on the haploid genome on different chromosomes. The relevance of mutagenesis and polyploidization for creation of pre-breeding material will be discussed. Especially the utilization of tetraploid hydrangeas seems to be a useful tool for the development of new hydrangea varieties.   &nbsp

Guidance on aneugenicity assessment

The EFSA Scientific Committee was asked to provide guidance on the most appropriate in vivo tests to follow up on positive in vitro results for aneugenicity, and on the approach to risk assessment for substances that are aneugenic but not clastogenic nor causing gene mutations. The Scientific Committee confirmed that the preferred approach is to perform an in vivo mammalian erythrocyte micronucleus test with a relevant route of administration. If this is positive, it demonstrates that the substance is aneugenic in vivo. A negative result with evidence that the bone marrow is exposed to the test substance supports a conclusion that aneugenic activity is not expressed in vivo. If there is no evidence of exposure to the bone marrow, a negative result is viewed as inconclusive and further studies are required. The liver micronucleus assay, even though not yet fully validated, can provide supporting information for substances that are aneugenic following metabolic activation. The gastrointestinal micronucleus test, conversely, to be further developed, may help to assess aneugenic potential at the initial site of contact for substances that are aneugenic in vitro without metabolic activation. Based on the evidence in relation to mechanisms of aneugenicity, the Scientific Committee concluded that, in principle, health-based guidance values can be established for substances that are aneugenic but not clastogenic nor causing gene mutations, provided that a comprehensive toxicological database is available. For situations in which the toxicological database is not sufficient to establish health-based guidance values, some approaches to risk assessment are proposed. The Scientific Committee recommends further development of the gastrointestinal micronucleus test, and research to improve the understanding of aneugenicity to support risk assessment

Associations between depressive symptoms and disease progression in older patients with chronic kidney disease: results of the EQUAL study

Background Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex. Methods CKD patients (>= 65 years; estimated glomerular filtration rate <= 20 mL/min/1.73 m(2)) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off <= 70; 0-100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders. Results Overall kidney function decline in 1326 patients was -0.12 mL/min/1.73 m(2)/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03-1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality). Conclusions There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men

Carrier bound synthetic oligopeptides in ELISA test systems for distinction between HIV-1 and HIV-2 infection

A series of synthetic carrier bound oligopeptides derived from corresponding regions of the core and envelope proteins of HIV-1 and HIV-2 were used in enzyme-linked immunoabsorbent assays (ELISA) for serodiagnosis of HIV-1 and HIV-2 infected individuals. The combination of peptides from regions either conserved or highly variable between the two virus types allowed the identification of HIV infection in general and the differentiation between HIV-1 and HIV-2. No specific reaction was found in seronegative individuals. The use of peptides bound to the same polystyrene carrier as in peptide synthesis allowed the establishment of a highly specific and sensitive test system without the risk of unspecific cross-reaction due to contamination with bacterial or cellular protein material

Genotoxicity assessment of chemical mixtures

The EFSA Scientific Committee addressed in this document the peculiarities related to the genotoxicity assessment of chemical mixtures. The EFSA Scientific Committee suggests that first a mixture should be chemically characterised as far as possible. Although the characterisation of mixtures is relevant also for other toxicity aspects, it is particularly significant for the assessment of genotoxicity. If a mixture contains one or more chemical substances that are individually assessed to be genotoxic in vivo via a relevant route of administration, the mixture raises concern for genotoxicity. If a fully chemically defined mixture does not contain genotoxic chemical substances, the mixture is of no concern with respect to genotoxicity. If a mixture contains a fraction of chemical substances that have not been chemically identified, experimental testing of the unidentified fraction should be considered as the first option or, if this is not feasible, testing of the whole mixture should be undertaken. If testing of these fraction(s) or of the whole mixture in an adequately performed set of in vitro assays provides clearly negative results, the mixture does not raise concern for genotoxicity. If in vitro testing provides one or more positive results, an in vivo follow‐up study should be considered. For negative results in the in vivo follow‐up test(s), the possible limitations of in vivo testing should be weighed in an uncertainty analysis before reaching a conclusion of no concern with respect to genotoxicity. For positive results in the in vivo follow‐up test(s), it can be concluded that the mixture does raise a concern about genotoxicity

Kidney Failure Prediction Models: A Comprehensive External Validation Study in Patients with Advanced CKD

Background: Various prediction models have been developed to predict the risk of kidney failure in patients with CKD. However, guideline-recommended models have yet to be compared head to head, their validation in patients with advanced CKD is lacking, and most do not account for competing risks.Methods: To externally validate 11 existing models of kidney failure, taking the competing risk of death into account, we included patients with advanced CKD from two large cohorts: the European Quality Study (EQUAL), an ongoing European prospective, multicenter cohort study of older patients with advanced CKD, and the Swedish Renal Registry (SRR), an ongoing registry of nephrology-referred patients with CKD in Sweden. The outcome of the models was kidney failure (defined as RRT-treated ESKD). We assessed model performance with discrimination and calibration.Results: The study included 1580 patients from EQUAL and 13,489 patients from SRR. The average c statistic over the 11 validated models was 0.74 in EQUAL and 0.80 in SRR, compared with 0.89 in previous validations. Most models with longer prediction horizons overestimated the risk of kidney failure considerably. The 5-year Kidney Failure Risk Equation (KFRE) overpredicted risk by 10%-18%. The four- and eight-variable 2-year KFRE and the 4-year Grams model showed excellent calibration and good discrimination in both cohorts.Conclusions: Some existing models can accurately predict kidney failure in patients with advanced CKD. KFRE performed well for a shorter time frame (2 years), despite not accounting for competing events. Models predicting over a longer time frame (5 years) overestimated risk because of the competing risk of death. The Grams model, which accounts for the latter, is suitable for longer-term predictions (4 years)

Predicting Kidney Failure, Cardiovascular Disease and Death in Advanced CKD Patients

Introduction: Predicting the timing and occurrence of kidney replacement therapy (KRT), cardiovascular events, and death among patients with advanced chronic kidney disease (CKD) is clinically useful and relevant. We aimed to externally validate a recently developed CKD G4+ risk calculator for these outcomes and to assess its potential clinical impact in guiding vascular access placement. Methods: We included 1517 patients from the European Quality (EQUAL) study, a European multicentre prospective cohort study of nephrology-referred advanced CKD patients aged ≥65 years. Model performance was assessed based on discrimination and calibration. Potential clinical utility for timing of referral for vascular access placement was studied with diagnostic measures and decision curve analysis (DCA). Results: The model showed a good discrimination for KRT and “death after KRT,” with 2-year concordance (C) statistics of 0.74 and 0.76, respectively. Discrimination for cardiovascular events (2-year C-statistic: 0.70) and overall death (2-year C-statistic: 0.61) was poorer. Calibration was fairly accurate. Decision curves illustrated that using the model to guide vascular access referral would generally lead to less unused arteriovenous fistulas (AVFs) than following estimated glomerular filtration rate (eGFR) thresholds. Conclusion: This study shows moderate to good predictive performance of the model in an older cohort of nephrology-referred patients with advanced CKD. Using the model to guide referral for vascular access placement has potential in combating unnecessary vascular surgeries