Chrom(VI)-Analyse, Chrom(VI)-Belastungen nordrhein-westfälischer Böden und Modellversuche zur Chrom(VI)-Reduktion und Chrom(III)-Oxidation in Böden

Chrom kann aufgrund vielfältiger industrieller Nutzung als Cr(III) und Cr(VI) in Umweltkompartimente wie Böden gelangen. Insbesondere Cr(VI) kann aufgrund seiner hohen Mobilität und Toxizität ein wesentliches Umweltrisiko darstellen. Im Auftrag des ehemaligen Landesumweltamtes Nordrhein-Westfalen wurden 116 belastete und unbelastete Bodenproben aus Nordrhein-Westfalen mit Cr-Gesamtgehalten (Königswasseraufschluss) von 5 bis 25245 mg kg-1 unter Verwendung der DIN-Methode 19734 (K2HPO4-Extraktion) kolorimetrisch nach DPC-Anfärbung auf ihre mobilen Cr(VI)-Gehalte und vergleichend mittels GF-AAS-Messung auf ihre mobilen Crgesamt-Gehalte untersucht. Die Gehalte an mobilem Cr(VI) betrugen -1 (Median und Mittelwert: 0,15 und 4,87 mg kg-1). Die mobilen Crgesamt-Gehalte lagen im selben Bereich (-1; Median und Mittelwert: 0,08 und 4,45 mg kg-1). Trotz einiger methodischer Probleme bei der Cr(VI)-Bestimmung zeigten die Ergebnisse, dass die mobilen Cr(VI)-Gehalte von 108 der 116 untersuchten Bodenproben als unbedenklich anzusehen sind. Lediglich bei fünf Proben wurden Cr(VI)-Belastungen von 0,13 bis 0,5 mg kg-1 gemessen; drei Proben waren mit 23, 108 und 379 mg kg-1 stark mit mobilem Cr(VI) belastet. Die Cr(VI)-Analyse von Bodenproben nach DIN 19734 ist zum Teil mit Problemen behaftet. Sowohl eine Oxidation von Cr(III) zu Cr(VI) als auch eine Reduktion von Cr(VI) zu Cr(III) fand während der Zeit von der Extraktion bis zur Messung bei einigen Proben statt. Vor allem störte die Anwesenheit von gelösten Huminstoffen und organischen Cr(III)-Komplexen in den K2HPO4-Extrakten stark humoser, saurer Proben die Cr(VI)-Analyse. Deshalb wurde eine modifizierte DIN-Methode entwickelt, bei der die Ausfällung von Huminstoffen und organisch komplexiertem Cr(III) mit MgCl2 und FeCl3 anstelle von Al2(SO4)3 erfolgt. Mit diesen Veränderungen konnten die methodischen Probleme der Cr(VI)-Analyse vermindert werden. Modellversuche zeigten, dass die Reaktionsgeschwindigkeit der Cr(VI)-Reduktion mit sinkendem pH-Wert, zunehmendem OC-Gehalt und steigender Cr(VI)-Zugabe zunahm. Eine Zugabe an zersetzbarer organischer Substanz und/oder anaerobe Bedingungen beschleunigten zusätzlich die Cr(VI)-Reduktion. Die zunächst sehr schnelle und dann zunehmend langsamere Reduktionskinetik konnte durch zwei gekoppelte Funktionen der Reaktionskinetik 1. Ordnung am besten dargestellt werden. Insgesamt ließ sich die Cr(VI)-Reduktion anhand der folgenden multiplen Regressionsgleichung beschreiben: log Cr(VI)t = 0,98 log Cr(VI)-Zugabe - 0,46 log OC + 0,33 pH - 0,35 t, r2 = 0,805, N = 170. Eine Cr(III)-Oxidation zu Cr(VI) durch Mn(III, IV)-Oxide fand nur sehr begrenzt statt (max. 2 % von 500 mg Cr(III) kg-1). Die Reaktionsgeschwindigkeit der Cr(III)-Oxidation bei humusarmen Proben verlief mit steigendem pH-Wert bis 5, zunehmendem Mn(III, IV)-Gehalt und abnehmendem OC-Gehalt schneller. Bei pH-Werten > 6 war die Cr(III)-Oxidation kinetisch zwar retardiert, das gebildete Cr(VI) blieb aber bis zu 1944 Stunden stabil. Die Cr(VI)-Bildung in humusarmen Proben mit pH > 6 konnte durch folgende multiple Regressionsgleichung beschrieben werden: log Cr(VI)t = 0,30 pH + 0,75 log Mn - 0,72 log OC + 0,28 log t, r2 = 0,944, N = 15. Bei humosen Proben zeigte sich keine nennenswerte Cr(III)-Oxidation. Anhand dieser Ergebnisse wurden Vorschläge für die Melioration Cr(VI)-belasteter Böden abgeleitet.Chromium(VI) analysis, chromium(VI) contaminations of soils from North Rhine-Westphalia (Germany), and model experiments for chromium(VI) reduction and chromium(III) oxidation in soils Due to the widespread industrial use of chromium as Cr(III) and Cr(VI) it can contaminate environmental compartments such as soils. Particularly Cr(VI) can represent a significant environmental risk because of its high mobility and toxicity. On behalf of the former State Environment Agency of North Rhine-Westphalia 116 contaminated and non-contaminated soil samples from North Rhine-Westphalia, revealing a wide range of total chromium content (5 - 25245 mg kg-1; aqua regia digestion), were investigated for their contents of mobile Cr(VI) according to the German standard DIN method 19734 (K2HPO4 extraction). The contents of mobile Cr(VI), which were measured by a colorimetric method with DPC, ranged from -1 (median and mean: 0.15 and 4.87 mg kg-1). The contents of mobile Crtotal, which were determined in the same extracts by GF-AAS, varied in a similar range (-1; median and mean: 0.08 and 4.45 mg kg-1). Despite of some analytical problems of the Cr(VI) determination, the results showed that the mobile Cr(VI) contents of 108 from 116 investigated soil samples can be considered as harmless. In five soil samples a contamination with mobile Cr(VI) was observed in the range of 0.13 to 0.5 mg kg-1; three soil samples which contained 23, 108, and 379 mg Cr(VI) kg-1 were strongly contaminated. The Cr(VI) analysis according to the German standard method DIN 19734 proved to be problematic for certain soil samples. Both an oxidation of Cr(III) to Cr(VI) and a reduction of Cr(VI) to Cr(III) took place during the period between extraction and measurement. Especially, the presence of dissolved humic matter and organic Cr(III) complexes in the K2HPO4 extracts of acid humic soil samples disturbed the Cr(VI) analysis. Therefore, a modified DIN method was developed by using MgCl2 and FeCl3 instead of Al2(SO4)3 for a better precipitation of dissolved humic matter and organically complexed Cr(III). With these changes, the analytical problems could be reduced. Model experiments with soil samples revealed that the rate of Cr(VI) reduction became noticeably faster with decreasing pH, increasing OC content, and increasing Cr(VI) addition. Furthermore, the Cr(VI) reduction was accelerated by an addition of decomposable organic matter and/or anaerobic conditions. The Cr(VI) reduction showed an initially fast reaction rate followed by a slow reaction rate. It could be best described by two coupled functions of 1. order reaction kinetics. Altogether, the Cr(VI) reduction could be described by the following multiple regression equation: log Cr(VI)t = 0.98 log Cr(VI) addition - 0.46 log OC + 0.33 pH - 0.35 t, r2 = 0.805, N = 170. An oxidation of Cr(III) to Cr(VI) by Mn(III, IV) oxides also occurred but it was limited (max. 2 % of added 500 mg Cr(III) kg-1). The rate of Cr(III) oxidation became faster with increasing pH up to 5, increasing Mn(III, IV) content, and decreasing OC content in humus-poor soil samples. At pH values > 6, the Cr(III) oxidation was kinetically retarded, but the formed Cr(VI) remained stable until the end of the experiments (up to 1944 hours). The Cr(VI) formation in humus-poor soil samples with pH > 6 could be described by the following multiple regression equation: log Cr(VI)t = 0.30 pH + 0.75 log Mn - 0.72 log OC + 0.28 log t, r2 = 0.944, N = 15. In humic soil samples a significant Cr(III) oxidation did not occur. On the basis of these results proposals for a melioration of Cr(VI)-contaminated soils were derived

Effectiveness of gamma ray irradiation and ethyl methane sulphonate on in vitro mutagenesis of strawberry

The experiment was conducted to study the effect of gamma-ray irradiation on the high concentration thidiazuron (TDZ) produced buds. In vitro buds were irradiated with different gamma-ray doses. Akihime cultivar (‘Akihime’) was irradiated with the doses of 0, 30, 80, 130, 180, and 230 Gy while ‘DNKW001 accession’ (‘DNKW001’) was exposed to the doses of 0, 30, 80, 130, 180, 230, 280, 300 and 325 Gy and similar doses of gamma rays + EMS 7uM (GRE) treatments. Survival rate and plantlet performance of DNKW001 in gamma ray + EMS 7uM treatment declined profoundly with increasing doses and LD50 was lower (104 Gy) than LD50 in gamma ray irradiation (177 Gy) alone. Variants of plantlets were detected in pre (white streaked leaf and bigger petiole with distorted leaf) and post acclimations (dwarf, dwarf-necrosis, variegated, dark-rigid-thick leaf, rumpled leaf, heart shape-bright red fruit). Hexadecaploid of Akihime and pentadecaploid, 13x + 4 chormosome, and diplodecaploid of DNKW001 were discovered sturdy plants with thicker leaf and bigger pollen than octoploid plant, while the monosomic octoploid performed a dwarf plant. Outstanding variants based on fruit weight, total soluble solid content and color in plot of Principle Component Analysis (PCA) were selected and proved as mutants in DNA level. Gamma ray irradiation + EMS was more effective to generate more type and magnitude of variants. Irradiation dose less than 130 Gy was ample for generating variant plants of strawberry.Keywords: Survival rate, LD50, dwarf, thick leaf, monosomic octoploid, hexadecaploid, diplodecaploid, PCAAfrican Journal of Biotechnology Vol. 12(30), pp. 4803-481

Cardiomyocytes from human pluripotent stem cells: from laboratory curiosity to industrial biomedical platform

Cardiomyocytes from human pluripotent stem cells (hPSCs-CMs) could revolutionise biomedicine. Global burden of heart failure will soon reach USD $90bn, while unexpected cardiotoxicity underlies 28% of drug withdrawals. Advances in hPSC isolation, Cas9/CRISPR genome engineering and hPSC-CM differentiation have improved patient care, progressed drugs to clinic and opened a new era in safety pharmacology. Nevertheless, predictive cardiotoxicity using hPSC-CMs contrasts from failure to almost total success. Since this likely relates to cell immaturity, efforts are underway to use biochemical and biophysical cues to improve many of the ~ 30 structural and functional properties of hPSC-CMs towards those seen in adult CMs. Other developments needed for widespread hPSC-CM utility include subtype specification, cost reduction of large scale differentiation and elimination of the phenotyping bottleneck. This review will consider these factors in the evolution of hPSC-CM technologies, as well as their integration into high content industrial platforms that assess structure, mitochondrial function, electrophysiology, calcium transients and contractility. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel

Efficacy and safety of autologous haematopoietic stem cell transplantation versus alemtuzumab, ocrelizumab, ofatumumab or cladribine in relapsing remitting multiple sclerosis (StarMS): protocol for a randomised controlled trial

Introduction: Autologous haematopoietic stem cell transplantation (aHSCT) is increasingly used as treatment for patients with active multiple sclerosis (MS), typically after failure of disease-modifying therapies (DMTs). A recent phase III trial, ‘Multiple Sclerosis International Stem Cell Transplant, MIST’, showed that aHSCT resulted in prolonged time to disability progression compared with DMTs in patients with relapsing remitting MS (RRMS). However, the MIST trial did not include many of the current high-efficacy DMTs (alemtuzumab, ocrelizumab, ofatumumab or cladribine) in use in the UK within the control arm, which are now offered to patients with rapidly evolving severe MS (RES-MS) who are treatment naïve. There remain, therefore, unanswered questions about the relative efficacy and safety of aHSCT over these high-efficacy DMTs in these patient groups. The StarMS trial (Autologous Stem Cell Transplantation versus Alemtuzumab, Ocrelizumab, Ofatumumab or Cladribine in Relapsing Remitting Multiple Sclerosis) will assess the efficacy, safety and long-term impact of aHSCT compared with high-efficacy DMTs in patients with highly active RRMS despite the use of standard DMTs or in patients with treatment naïve RES-MS. Methods and analysis: StarMS is a multicentre parallel-group rater-blinded randomised controlled trial with two arms. A total of 198 participants will be recruited from 19 regional neurology secondary care centres in the UK. Participants will be randomly allocated to the aHSCT arm or DMT arm in a 1:1 ratio. Participants will remain in the study for 2 years with follow-up visits at 3, 6, 9, 12, 18 and 24 months postrandomisation. The primary outcome is the proportion of patients who achieve ‘no evidence of disease activity’ during the 2-year postrandomisation follow-up period in an intention to treat analysis. Secondary outcomes include efficacy, safety, cost-effectiveness and immune reconstitution of aHSCT and the four high-efficacy DMTs. Ethics and dissemination: The study was approved by the Yorkshire and Humber—Leeds West Research Ethics Committee (20/YH/0061). Participants will provide written informed consent prior to any study specific procedures. The study results will be submitted to a peer-reviewed journal and abstracts will be submitted to relevant national and international conferences. Trial registration number: ISRCTN88667898