The incidence of pediatric acute kidney injury is increased when identified by a change in a creatinine-based electronic alert.

A prospective national cohort study was undertaken to collect data on all cases of pediatric (under 18 yrs of age) acute kidney injury (AKI) identified by a biochemistry-based electronic alert using the Welsh National electronic AKI reporting system. Herein we describe the utility and limitation of using this modification of the KDIGO creatinine-based system data set to characterize pediatric AKI. Of 1,343 incident episodes over a 30-month period, 34.5% occurred in neonates of which 83.8% were AKI stage 1. Neonatal 30-day mortality was 4.1%, with 73.3% of this being accounted for by patients treated in an Intensive Care Unit. In the non-neonatal group, 76.1% were AKI stage 1. Hospital-acquired AKI accounted for 40.1% of episodes while community-acquired AKI represented 29.4% of cases within which 33.9% were admitted to hospital and 30.5% of cases were unclassified. Non-neonatal 30-day mortality was 1.2%, with half of this accounted for by patients treated in the Intensive Care Unit. Nonrecovery of renal function at 30 days occurred in 28% and was significantly higher in patients not admitted to hospital (45% vs. 20%). The reported incidence of AKI in children was far greater than previously reported in studies reliant on clinical identification of adult AKI or hospital coding data. Mortality was highest in neonates and driven by those in the Intensive Care Unit. Nonrecovery of renal function and persistent renal impairment was more common in non-neonates and was especially high in patients with community-acquired AKI who were not hospitalized.

Seasonal pattern of incidence and outcome of Acute Kidney Injury: A national study of Welsh AKI electronic alerts.

OBJECTIVES: To identify any seasonal variation in the occurrence of, and outcome following Acute Kidney Injury. METHODS: The study utilised the biochemistry based AKI electronic (e)-alert system established across the Welsh National Health Service to collect data on all AKI episodes to identify changes in incidence and outcome over one calendar year (1st October 2015 and the 30th September 2016). RESULTS: There were total of 48 457 incident AKI alerts. The highest proportion of AKI episodes was seen in the quarter of January to March (26.2%), and the lowest in the quarter of October to December (23.3%, P < .001). The same trend was seen for both community-acquired and hospital-acquired AKI sub-sets. Overall 90 day mortality for all AKI was 27.3%. In contrast with the seasonal trend in AKI occurrence, 90 day mortality after the incident AKI alert was significantly higher in the quarters of January to March and October to December compared with the quarters of April to June and July to September (P < .001) consistent with excess winter mortality reported for likely underlying diseases which precipitate AKI. CONCLUSIONS: In summary we report for the first time in a large national cohort, a seasonal variation in the incidence and outcomes of AKI. The results demonstrate distinct trends in the incidence and outcome of AKI.

A Theoretical and Empirical Integrated Method to Select the Optimal Combined Signals for Geometry-Free and Geometry-Based Three-Carrier Ambiguity Resolution.

Twelve GPS Block IIF satellites, out of the current constellation, can transmit on three-frequency signals (L1, L2, L5). Taking advantages of these signals, Three-Carrier Ambiguity Resolution (TCAR) is expected to bring much benefit for ambiguity resolution. One of the research areas is to find the optimal combined signals for a better ambiguity resolution in geometry-free (GF) and geometry-based (GB) mode. However, the existing researches select the signals through either pure theoretical analysis or testing with simulated data, which might be biased as the real observation condition could be different from theoretical prediction or simulation. In this paper, we propose a theoretical and empirical integrated method, which first selects the possible optimal combined signals in theory and then refines these signals with real triple-frequency GPS data, observed at eleven baselines of different lengths. An interpolation technique is also adopted in order to show changes of the AR performance with the increase in baseline length. The results show that the AR success rate can be improved by 3% in GF mode and 8% in GB mode at certain intervals of the baseline length. Therefore, the TCAR can perform better by adopting the combined signals proposed in this paper when the baseline meets the length condition.

Utility of electronic AKI alerts in intensive care: A national multicentre cohort study.

BACKGROUND: Electronic AKI alerts highlight changes in serum creatinine compared to the patient's own baseline. Our aim was to identify all AKI alerts and describe the relationship between electronic AKI alerts and outcome for AKI treated in the Intensive Care Unit (ICU) in a national multicentre cohort. METHODS: A prospective cohort study was undertaken between November 2013 and April 2016, collecting data on electronic AKI alerts issued. RESULTS: 10% of 47,090 incident AKI alerts were associated with ICU admission. 90-day mortality was 38.2%. Within the ICU cohort 48.8% alerted in ICU. 51.2% were transferred to ICU within 7days of the alert, of which 37.8% alerted in a hospital setting (HA-AKI) and 62.2% in a community setting (CA-AKI). Mortality was higher in patients transferred to ICU following the alert compared to those who had an incident alert on the ICU (p<0.001), and was higher in HA-AKI (45.3%) compared to CA-AKI (39.5%) (35.0%, p=0.01). In the surviving patients, the proportion of patient recovering renal function following, was significantly higher in HA-AKI alerting (84.2%, p=0.004) and CA-AKI alerting patients (87.6%, p<0.001) compared to patients alerting on the ICU (78.3%). CONCLUSION: The study provides a nationwide characterisation of AKI in ICU highlighting the high incidence and its impact on patient outcome. The data also suggests that within the cohort of AKI patients treated in the ICU there are significant differences in the presentation and outcome between those patients that require transfer to the ICU after AKI is identified and those who develop AKI following ICU admission. Moreover, the study demonstrates that using AKI e-alerts provides a centralised resource which does not rely on clinical diagnosis of AKI or coding, resulting in a robust data set which can be used to define the incidence and outcome of AKI in the ICU setting.

Coupling the GAL4 UAS system with alcR for versatile cell type-specific chemically inducible gene expression in Arabidopsis.

The Aspergillus alc regulon encodes a transcription factor, ALCR, which regulates transcription from cognate promoters such as alcA(p). In the presence of suitable chemical inducers, ALCR activates gene expression from alcA(p). The alc regulon can be transferred to other species and can be used to control the expression of reporter, metabolic and developmental genes in response to low-level ethanol exposure. In this paper, we describe a versatile system for targeting the alc regulon to specific cell types in Arabidopsis by driving ALCR expression from the GAL4 upstream activator sequence (UAS). Large numbers of Arabidopsis lines are available in which GAL4 is expressed in a variety of spatial patterns and, in turn, drives the expression of any gene cloned downstream of the UAS. We have used a previously characterized line that directs gene expression to the endosperm to demonstrate spatially restricted ethanol-inducible gene expression. We also show that the domain of inducible gene expression can easily be altered by crossing the UAS::ALCR cassette into different driver lines. We conclude that this gene switch can be used to drive gene expression in a highly responsive, but spatially restricted, manner.

Understanding Electronic AKI Alerts: Characterization by Definitional Rules.

INTRODUCTION: Automated acute kidney injury (AKI) electronic alerts are based on comparing creatinine with historic results. METHODS: We report the significance of AKI defined by 3 "rules" differing in the time period from which the baseline creatinine is obtained, and AKI with creatinine within the normal range. RESULTS: A total of 47,090 incident episodes of AKI occurred between November 2013 and April 2016. Rule 1 (>26 µmol/l increase in creatinine within 48 hours) accounted for 9.6%. Rule 2 (≥50% increase in creatinine within previous 7 days) and rule 3 (≥50% creatinine increase from the median value of results within the last 8-365 days) accounted for 27.3% and 63.1%, respectively. Hospital-acquired AKI was predominantly identified by rules 1 and 2 (71.7%), and community-acquired AKI (86.3%) by rule 3. Stages 2 and 3 were detected by rules 2 and 3. Ninety-day mortality was higher in AKI rule 2 (32.4%) than rule 1 (28.3%, P < 0.001) and rule 3 (26.6%, P < 0.001). Nonrecovery of renal function (90 days) was lower for rule 1 (7.9%) than rule 2 (22.4%, P < 0.001) and rule 3 (16.5%, P < 0.001). We found that 19.2% of AKI occurred with creatinine values within normal range, in which mortality was lower than that in AKI detected by a creatinine value outside the reference range (22.6% vs. 29.6%, P < 0.001). DISCUSSION: Rule 1 could only be invoked for stage 1 alerts and was associated with acute on chronic kidney disease acquired in hospital. Rule 2 was also associated with hospital-acquired AKI and had the highest mortality and nonrecovery. Rule 3 was the commonest cause of an alert and was associated with community-acquired AKI.

Acute Kidney Injury in the Era of the AKI E-Alert.

BACKGROUND AND OBJECTIVES: Our aim was to use a national electronic AKI alert to define the incidence and outcome of all episodes of community- and hospital-acquired adult AKI. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A prospective national cohort study was undertaken in a population of 3.06 million. Data were collected between March of 2015 and August of 2015. All patients with adult (≥18 years of age) AKI were identified to define the incidence and outcome of all episodes of community- and hospital-acquired AKI in adults. Mortality and renal outcomes were assessed at 90 days. RESULTS: There was a total of 31,601 alerts representing 17,689 incident episodes, giving an incidence of AKI of 577 per 100,000 population. Community-acquired AKI accounted for 49.3% of all incident episodes, and 42% occurred in the context of preexisting CKD (Chronic Kidney Disease Epidemiology Collaboration eGFR); 90-day mortality rate was 25.6%, and 23.7% of episodes progressed to a higher AKI stage than the stage associated with the alert. AKI electronic alert stage and peak AKI stage were associated with mortality, and mortality was significantly higher for hospital-acquired AKI compared with alerts generated in a community setting. Among patients who survived to 90 days after the AKI electronic alert, those who were not hospitalized had a lower rate of renal recovery and a greater likelihood of developing an eGFR<60 ml/min per 1.73 m2 for the first time, which may be indicative of development of de novo CKD. CONCLUSIONS: The reported incidence of AKI is far greater than the previously reported incidence in studies reliant on clinical identification of adult AKI or hospital coding data. Although an electronic alert system is Information Technology driven and therefore, lacks intelligence and clinical context, these data can be used to identify deficiencies in care, guide the development of appropriate intervention strategies, and provide a baseline against which the effectiveness of these interventions may be measured.

In vivo interaction between CDKA and eIF4A: a possible mechanism linking translation and cell proliferation.

In a proteomics-based screen for proteins interacting with cyclin-dependent protein kinase (CDK), we have identified a novel CDK complex containing the eukaryotic translation initiation factor, eIF4A. Reciprocal immunoprecipitations using antibodies against eIF4A indicate that the interaction is specific. The CDKA-eIF4A complex is abundant in actively proliferating and growing cells but is absent from cells that have ceased dividing. The CDKA-eIF4A complex contains kinase activity that is sensitive to the CDK-specific inhibitor roscovitine. This interaction points to a possible molecular mechanism linking cell proliferation with translational control.

Silencing by plant Polycomb-group genes requires dispersed trimethylation of histone H3 at lysine 27.

The plant Polycomb-group (Pc-G) protein CURLY LEAF (CLF) is required to repress targets such as AGAMOUS (AG) and SHOOTMERISTEMLESS (STM). Using chromatin immunoprecipitation, we identify AG and STM as direct targets for CLF and show that they carry a characteristic epigenetic signature of dispersed histone H3 lysine 27 trimethylation (H3K27me3) and localised H3K27me2 methylation. H3K27 methylation is present throughout leaf development and consistent with this, CLF is required persistently to silence AG. However, CLF is not itself an epigenetic mark as it is lost during mitosis. We suggest a model in which Pc-G proteins are recruited to localised regions of targets and then mediate dispersed H3K27me3. Analysis of transgenes carrying AG regulatory sequences confirms that H3K27me3 can spread to novel sequences in a CLF-dependent manner and further shows that H3K27me3 methylation is not sufficient for silencing of targets. We suggest that the spread of H3K27me3 contributes to the mitotic heritability of Pc-G silencing, and that the loss of silencing caused by transposon insertions at plant Pc-G targets reflects impaired spreading.

Arabidopsis SPO11-2 functions with SPO11-1 in meiotic recombination.

The Spo11 protein is a eukaryotic homologue of the archaeal DNA topoisomerase VIA subunit (topo VIA). In archaea it is involved, together with its B subunit (topo VIB), in DNA replication. However, most eukaryotes, including yeasts, insects and vertebrates, instead have a single gene for Spo11/topo VIA and no homologues for topo VIB. In these organisms, Spo11 mediates DNA double-strand breaks that initiate meiotic recombination. Many plant species, in contrast to other eukaryotes, have three homologues for Spo11/topo VIA and one for topo VIB. The homologues in Arabidopsis, AtSPO11-1, AtSPO11-2 and AtSPO11-3, all share 20-30% sequence similarity with other Spo11/topo VIA proteins, but their functional relationship during meiosis or other processes is not well understood. Previous genetic evidence suggests that AtSPO11-1 is a true orthologue of Spo11 in other eukaryotes and is required for meiotic recombination, whereas AtSPO11-3 is involved in DNA endo-reduplication as a part of the topo VI complex. In this study, we show that plants homozygous for atspo11-2 exhibit a severe sterility phenotype. Both male and female meiosis are severely disrupted in the atspo11-2 mutant, and this is associated with severe defects in synapsis during the first meiotic division and reduced meiotic recombination. Further genetic analysis revealed that AtSPO11-1 and AtSPO11-2 genetically interact, i.e. plants heterozygous for both atspo11-1 and atspo11-2 are also sterile, suggesting that AtSPO11-1 and AtSPO11-2 have largely overlapping functions. Thus, the three Arabidopsis Spo11 homologues appear to function in two discrete processes, i.e. AtSPO11-1 and AtSPO11-2 in meiotic recombination and AtSPO11-3 in DNA replication.

RHL1 is an essential component of the plant DNA topoisomerase VI complex and is required for ploidy-dependent cell growth.

How cells achieve their final sizes is a pervasive biological question. One strategy to increase cell size is for the cell to amplify its chromosomal DNA content through endoreduplication cycles. Although endoreduplication is widespread in eukaryotes, we know very little about its molecular mechanisms. Successful progression of the endoreduplication cycle in Arabidopsis requires a plant homologue of archaeal DNA topoisomerase (topo) VI. To further understand how DNA is endoreduplicated and how this process is regulated, we isolated a dwarf Arabidopsis mutant, hyp7 (hypocotyl 7), in which various large cell types that in the wild type normally endoreduplicate multiple times complete only the first two rounds of endoreduplication and stall at 8C. HYP7 encodes the RHL1 (ROOT HAIRLESS 1) protein, and sequence analysis reveals that RHL1 has similarity to the C-terminal domain of mammalian DNA topo IIalpha, another type II topo that shares little sequence homology with topo VI. RHL1 shows DNA binding activity in vitro, and we present both genetic and in vivo evidence that RHL1 forms a multiprotein complex with plant topo VI. We propose that RHL1 plays an essential role in the topo VI complex to modulate its function and that the two distantly related topos, topo II and topo VI, have evolved a common domain that extends their function. Our data suggest that plant topo II and topo VI play distinct but overlapping roles during the mitotic cell cycle and endoreduplication cycle.

The alc-GR system: a modified alc gene switch designed for use in plant tissue culture.

The ALCR/alcA (alc) two-component, ethanol-inducible gene expression system provides stringent control of transgene expression in genetically modified plants. ALCR is an ethanol-activated transcription factor that can drive expression from the ALCR-responsive promoter (alcA). However, the alc system has been shown to have constitutive expression when used in plant callus or cell suspension cultures, possibly resulting from endogenous inducer produced in response to lowered oxygen availability. To widen the use of the alc system in plant cell culture conditions, the receptor domain of the rat glucocorticoid receptor (GR) was translationally fused to the C terminus of ALCR to produce ALCR-GR, which forms the basis of a glucocorticoid-inducible system (alc-GR). The alc-GR switch system was tested in tobacco (Nicotiana tabacum) Bright Yellow-2 suspension cells using a constitutively expressed ALCR-GR with four alternative alcA promoter-driven reporter genes: beta-glucuronidase, endoplasmic reticulum-targeted green fluorescent protein, haemagglutinin, and green fluorescent protein-tagged Arabidopsis (Arabidopsis thaliana) Arath;CDKA;1 cyclin-dependent kinase. Gene expression was shown to be stringently dependent on the synthetic glucocorticoid dexamethasone and, in cell suspensions, no longer required ethanol for induction. Thus, the alc-GR system allows tight control of alcA-driven genes in cell culture and complements the conventional ethanol switch used in whole plants.

The ethanol switch: a tool for tissue-specific gene induction during plant development.

Controlled gene expression in time and space is a powerful tool for the analysis of gene function during plant development. Here, we report ethanol inducible gene expression in defined sub-domains of the shoot apical and floral meristems. For this, expression of an ethanol-regulated transcription factor, ALCR, is restricted to precise domains using specific promoters. Gene expression activation is followed using reporters under the control of the alcA promoter, which responds to ALCR only in the presence of the ethanol. We demonstrate that precise control of spatially limited gene expression can be achieved. The kinetics of reporter gene activation and inactivation following a pulse of ethanol induction shows that the system is dynamic and suitable for precise temporal control of expression. The system is both flexible and robust, permitting simultaneous expression of two genes in a given domain or, conversely, the expression of a gene in two separate domains. We also show that this strategy can be applied to mis-express genes with developmental roles, by manipulating expression of the SHOOT MERISTEMLESS (STM) and CYCLIN D3;1 (CYCD3;1) genes during plant development.