Fatigue among anaesthesiologists in Europe: Findings from a joint EBA/NASC survey

BACKGROUND

Anaesthesiologists deliver an increasing amount of patient care and often work long hours in operating theatres and intensive care units, with frequent on-calls and insufficient rest in between. In the long term, this will negatively influence mental and physical health and well being. As fatigue becomes more prevalent, this has predictable implications for patient safety and clinical effectiveness. 1.

OBJECTIVE

This study aimed to evaluate the prevalence, severity, causes and implications of work-related fatigue amongst specialist anaesthesiologists.

DESIGN

An online survey of specialist anaesthesiologists.

PARTICIPANTS

The survey was sent to anaesthesiologists in 42 European countries by electronic mail.

MAIN OUTCOME MEASURES

Responses from a 36-item online survey assessed work-related fatigue and its impact on anaesthesiologists in European countries.

RESULTS

Work-related fatigue was experienced in 91.6% of the 1508 respondents from 32 European countries. Fatigue was caused by their working patterns, clinical and nonclinical workloads, staffing issues and excessive work hours. Over 70% reported that work-related fatigue negatively impacted on their physical and mental health, emotional well being and safe commuting. Most respondents did not feel supported by their organisation to maintain good health and well being.

CONCLUSION

Work-related fatigue is a significant and widespread problem amongst anaesthesiologists. More education and increased awareness of fatigue and its adverse effects on patient safety, staff well being and physical and mental health are needed. Departments should ensure that their rotas and job plans comply with the European Working Time Directive (EWTD) and introduce a fatigue risk management system to mitigate the effects of fatigue.

Yarrowia lipolytica as a Platform for Punicic Acid Production

Punicic acid (PuA) is a polyunsaturated fatty acid with significant medical, biological, and nutraceutical properties. The primary source of punicic acid is the pomegranate seed oil obtained from fruits of trees that are mainly cultivated in subtropical and tropical climates. To establish sustainable production of PuA, various recombinant microorganisms and plants have been explored as platforms with limited efficiencies. In this study, the oleaginous yeast Yarrowia lipolytica was employed as a host for PuA production. First, growth and lipid accumulation of Y. lipolytica were evaluated in medium supplemented with pomegranate seed oil, resulting in the accumulation of lipids up to 31.2%, consisting of 22% PuA esterified in the fraction of glycerolipids. In addition, lipid-engineered Y. lipolytica strains, transformed with the bifunctional fatty acid conjugase/desaturase from Punica granatum (PgFADX), showed the ability to accumulate PuA de novo. PuA was detected in both polar and neutral lipid fractions, especially in phosphatidylcholine and triacylglycerols. Promoter optimization for PgFADX expression resulted in improved accumulation of PuA from 0.9 to 1.8 mg/g of dry cell weight. The best-producing strain expressing PgFADX under the control of a strong erythritol-inducible promoter produced 36.6 mg/L PuA. These results demonstrate that the yeast Y. lipolytica is a promising host for PuA production.

Fatigue amongst anaesthesiology and intensive care trainees in Europe: A matter of concern

BACKGROUND

There is a growing awareness of the effects of fatigue on trainee wellbeing and health. Trainees in anaesthesiology and intensive care work long hours, switching work schedules frequently with insufficient rest. This may have unwanted long-term effects on mental and physical health and emotional well being, resulting in burnout and affecting patient safety.

OBJECTIVE

The study aimed to evaluate the prevalence, severity, causes and effects of work-related fatigue in trainees in anaesthesiology and intensive care.

DESIGN

Online survey of trainees in anaesthesiology and intensive care.

SETTINGS

A total of 31 countries within Europe were included in the survey.

PARTICIPANTS

European anaesthesiology and intensive care trainees who responded to an invitation to take part by electronic mail or through social media.

MAIN OUTCOME MEASURES

Responses from a 29-item online survey to assess the realities within European countries with regards to work-related fatigue.

RESULTS

One thousand and two hundred trainees from 31 European countries answered the survey demonstrating that an alarming number of trainees were fatigued by their working patterns and night shifts. Trainees reported effects on personal well being, safe commuting and potential for clinical errors. Respondents described a lack of support from hospitals and management for recovery during and after night shifts.

CONCLUSION

Fatigue among trainees in anaesthesiology and intensive care has a significant impact on their well being and potentially, on the incidence of clinical errors. Current measures from authorities and hospital management are not sufficient to prevent serious fatigue, and therefore a fatigue risk management system should be considered. Failure to address this issue might lead to a further decline in trainees' wellbeing, their capacity to work in the speciality in the future, and potentially increase patient care errors.

Epidemiology and outcomes of hospital-acquired bloodstream infections in intensive care unit patients: the EUROBACT-2 international cohort study

PURPOSE

In the critically ill, hospital-acquired bloodstream infections (HA-BSI) are associated with significant mortality. Granular data are required for optimizing management, and developing guidelines and clinical trials.

METHODS

We carried out a prospective international cohort study of adult patients (≥ 18 years of age) with HA-BSI treated in intensive care units (ICUs) between June 2019 and February 2021.

RESULTS

2600 patients from 333 ICUs in 52 countries were included. 78% HA-BSI were ICU-acquired. Median Sequential Organ Failure Assessment (SOFA) score was 8 [IQR 5; 11] at HA-BSI diagnosis. Most frequent sources of infection included pneumonia (26.7%) and intravascular catheters (26.4%). Most frequent pathogens were Gram-negative bacteria (59.0%), predominantly Klebsiella spp. (27.9%), Acinetobacter spp. (20.3%), Escherichia coli (15.8%), and Pseudomonas spp. (14.3%). Carbapenem resistance was present in 37.8%, 84.6%, 7.4%, and 33.2%, respectively. Difficult-to-treat resistance (DTR) was present in 23.5% and pan-drug resistance in 1.5%. Antimicrobial therapy was deemed adequate within 24 h for 51.5%. Antimicrobial resistance was associated with longer delays to adequate antimicrobial therapy. Source control was needed in 52.5% but not achieved in 18.2%. Mortality was 37.1%, and only 16.1% had been discharged alive from hospital by day-28.

CONCLUSIONS

HA-BSI was frequently caused by Gram-negative, carbapenem-resistant and DTR pathogens. Antimicrobial resistance led to delays in adequate antimicrobial therapy. Mortality was high, and at day-28 only a minority of the patients were discharged alive from the hospital. Prevention of antimicrobial resistance and focusing on adequate antimicrobial therapy and source control are important to optimize patient management and outcomes.

Toehold switch based biosensors for sensing the highly trafficked rosewood Dalbergia maritima

Nucleic acid sensing is a 3 decades old but still challenging area of application for different biological sub-domains, from pathogen detection to single cell transcriptomics analysis. The many applications of nucleic acid detection and identification are mostly carried out by PCR techniques, sequencing, and their derivatives used at large scale. However, these methods’ limitations on speed, cost, complexity and specificity have motivated the development of innovative detection methods among which nucleic acid biosensing technologies seem promising. Toehold switches are a particular class of RNA sensing devices relying on a conformational switch of secondary structure induced by the pairing of the detected trigger RNA with a de novo designed synthetic sensing mRNA molecule. Here we describe a streamlined methodology enabling the development of such a sensor for the RNA-mediated detection of an endangered plant species in a cell-free reaction system. We applied this methodology to help identify the rosewood Dalbergia maritima, a highly trafficked wood, whose protection is limited by the capacity of the authorities to distinguish protected logs from other unprotected but related species. The streamlined pipeline presented in this work is a versatile framework enabling cheap and rapid development of new sensors for custom RNA detection.

Twenty years of evolution and diversification of digitaria streak virus in Digitaria setigera

Within the family Geminiviridae, the emergence of new species results from their high mutation and recombination rates. In this study, we report the variability and evolution of digitaria streak virus (DSV), a mastrevirus isolated in 1986 from the grass Digitaria setigera in an island of the Vanuatu archipelago. Viral DNA of DSV samples was amplified from D. setigera specimens, derived from the naturally infected original plant, which were propagated in different laboratories in France and Italy for more than 20 years. From the consensus sequences, the nucleotide substitution rate was estimated for the period between a sample and the original sequence published in 1987, as well as for the period between samples. In addition, the intra-host genetic complexity and diversity of 8 DSV populations with a total of 165 sequenced haplotypes was characterized. The evolutionary rate of DSV was estimated to be between 1.13 × 10⁻⁴ and 9.87 × 10⁻⁴ substitutions/site/year, within the ranges observed in other single-stranded DNA viruses and RNA viruses. Bioinformatic analyses revealed high variability and heterogeneity in DSV populations, which confirmed that mutant spectra are continuously generated and are organized as quasispecies. The analysis of polymorphisms revealed nucleotide substitution biases in viral genomes towards deamination and oxidation of single-stranded DNA. The differences in variability in each of the genomic regions reflected a dynamic and modular evolution in the mutant spectra that was not reflected in the consensus sequences. Strikingly, the most variable region of the DSV genome, encoding the movement protein, showed rapid fixation of the mutations in the consensus sequence and a concomitant dN/dS ratio of 6.130, which suggests strong positive selection in this region. Phylogenetic analyses revealed a possible divergence in three genetic lineages from the original Vanuatu DSV isolate.

Exploring Hyperoxia Effects in Cancer-From Perioperative Clinical Data to Potential Molecular Mechanisms

Increased inspiratory oxygen concentration is constantly used during the perioperative period of cancer patients to prevent the potential development of hypoxemia and to provide an adequate oxygen transport to the organs, tissues and cells. Although the primary tumours are surgically removed, the effects of perioperative hyperoxia exposure on distal micro-metastases and on circulating cancer cells can potentially play a role in cancer progression or recurrence. In clinical trials, hyperoxia seems to increase the rate of postoperative complications and, by delaying postoperative recovery, it can alter the return to intended oncological treatment. The effects of supplemental oxygen on the long-term mortality of surgical cancer patients offer, at this point, conflicting results. In experimental studies, hyperoxia effects on cancer biology were explored following multiple pathways. In cancer cell cultures and animal models, hyperoxia increases the production of reactive oxygen species (ROS) and increases the oxidative stress. These can be followed by the induction of the expression of Brain-derived neurotrophic factor (BDNF) and other molecules involved in angiogenesis and by the promotion of various degrees of epithelial mesenchymal transition (EMT).

Sevoflurane Modulates AKT Isoforms in Triple Negative Breast Cancer Cells. An Experimental Study

(1) Background: Triple negative breast cancer (TNBC) is a highly aggressive tumor, associated with high rates of early distant recurrence and short survival times, and treatment may require surgery, and thus anesthesia. The effects of anesthetic drugs on cancer progression are under scrutiny, but published data are controversial, and the involved mechanisms unclear. Anesthetic agents have been shown to modulate several molecular cascades, including PI3K/AKT/mTOR. AKT isoforms are frequently amplified in various malignant tumors and associated with malignant cell survival, proliferation and invasion. Their activation is often observed in human cancers and is associated with decreased survival rate. Certain anesthetics are known to affect hypoxia cell signaling mechanisms by upregulating hypoxia-inducible factors (HIFs). (2) Methods: MCF-10A and MDA-MB 231 cells were cultivated and CellTiter-Blue^® Cell Viability assay, 2D and 3D matrigel assay, immunofluorescence assays and gene expressions assay were performed after exposure to different sevoflurane concentrations. (3) Results: Sevoflurane exposure of TNBC cells results in morphological and behavioral changes. Sevoflurane differently influences the AKT isoforms expression in a time-dependent manner, with an important early AKT3 upregulation. The most significant effects occur at 72 h after 2 mM sevoflurane treatment and consist in increased viability, proliferation and aggressiveness and increased vimentin and HIF expression. (4) Conclusions: Sevoflurane exposure during surgery may contribute to cancer recurrence via AKT3 induced epithelial–mesenchymal transition (EMT) and by all three AKT isoforms enhanced cancer cell survival and proliferation.

Intra-abdominal hypertension and hypoxic respiratory failure together predict adverse outcome - A sub-analysis of a prospective cohort

PURPOSE

To assess whether the combination of intra-abdominal hypertension (IAH, intra-abdominal pressure ≥ 12 mmHg) and hypoxic respiratory failure (HRF, PaO2/FiO2 ratio < 300 mmHg) in patients receiving invasive ventilation is an independent risk factor for 90- and 28-day mortality as well as ICU- and ventilation-free days.

METHODS

Mechanically ventilated patients who had blood gas analyses performed and intra-abdominal pressure measured, were included from a prospective cohort. Subgroups were defined by the absence (Group 1) or the presence of either IAH (Group 2) or HRF (Group 3) or both (Group 4). Mixed-effects regression analysis was performed.

RESULTS

Ninety-day mortality increased from 16% (Group 1, n = 50) to 30% (Group 2, n = 20) and 27% (Group 3, n = 100) to 49% (Group 4, n = 142), log-rank test p < 0.001. The combination of IAH and HRF was associated with increased 90- and 28-day mortality as well as with fewer ICU- and ventilation-free days. The association with 90-day mortality was no longer present after adjustment for independent variables. However, the association with 28-day mortality, ICU- and ventilation-free days persisted after adjusting for independent variables.

CONCLUSIONS

In our sub-analysis, the combination of IAH and HRF was not independently associated with 90-day mortality but independently increased the odds of 28-day mortality, and reduced the number of ICU- and ventilation-free days.

Preoperative Cognitive Impairment and the Prevalence of Postoperative Delirium in Elderly Cancer Patients-A Prospective Observational Study

Preoperative cognitive impairment (PCI) in cancer patients includes a broad spectrum of neurocognitive changes produced by complex interplay of patient, tumoural and treatment-related factors. Reduced preoperative cognitive reserve can favour the emergence of postoperative delirium (POD). The study aims to document PCI prevalence and to assess the relationship with POD in elderly cancer patients. The prospective observational study included consecutive patients scheduled for elective surgery; PCI was assessed with Mini-Cog test and defined at a score ≤ 3, POD was screened using Nursing Delirium Screening Scale (Nu-DESC) and defined at a score ≥ 2. Data on education, American Society of Anesthesiologists (ASA) score, preoperative medications, substance use, comorbidities, sensorial deficits, surgery and anaesthesia type, anaesthetic drugs, Mini-Cog score, postoperative pain, Nu-DESC were collected. In total, 131 patients were enrolled, mean age 72.1 ± 5.9 years. PCI prevalence was 51.9% (n = 68). POD prevalence was 19.8% (n = 26), with significantly higher value in PCI patients (27.9% vs. 11.1%, p = 0.016). In multivariate analysis, Mini-Cog score ≤ 3 (OR = 2.6, p = 0.027), clock draw (OR: 2.9, p = 0.013), preoperative renal dysfunction (OR = 2.6, p = 0.012), morphine (OR = 2.7, p = 0.007), metoclopramide (OR = 6.6, p = 0.006), and high pain score (OR = 1.8, p = 0.018) had a significant association with POD development. In this sample of elderly patients, PCI had a high prevalence and predicted the emergence of POD. Incorporating Mini-Cog test into the preoperative evaluation of onco-geriatric patients seems valuable and feasible.

ICTV Virus Taxonomy Profile: Nanoviridae

Nanoviridae is a family of plant viruses (nanovirids) whose members have small isometric virions and multipartite, circular, single-stranded (css) DNA genomes. Each of the six (genus Babuvirus) or eight (genus Nanovirus) genomic DNAs is 0.9–1.1 kb and is separately encapsidated. Many isolates are associated with satellite-like cssDNAs (alphasatellites) of 1.0–1.1 kb. Hosts are eudicots, predominantly legumes (genus Nanovirus), and monocotyledons, predominantly in the order Zingiberales (genus Babuvirus). Nanovirids require a virus-encoded helper factor for transmission by aphids in a circulative, non-propagative manner. This is a summary of the ICTV Report on the family Nanoviridae, which is available at ictv.global/report/nanoviridae.

Technical Difficulties and Procedural Complications in Closing Malignant Esophageal-Respiratory Fistulas

The aim of the study was to outline technical difficulties and procedural complications of using partially covered esophageal self-expandable metal stents (SEMSs) in malignant esophageal respiratory fistulas (ERFs) as a palliative treatment option. In this study, 150 patients with malignant dysphagia underwent treatment with SEMSs. A total of 36 ERFs were detected through endoscopic or clinical assessment. Complete fistula sealing with SEMSs was possible in 35 of the 36 patients. The majority of fistulas were diagnosed in male patients with advanced esophageal cancer. All of them presented with prolonged dysphagia and cachexia. Stent migration or tumoral overgrowth was identified in 6 cases with recurrent dysphagia, and required a second stent insertion. SEMSs were highly efficient in 98% of the patients studied with ERFs, with successfully sealed ERFs after the first attempt, with an overall median survival rate of 92 days. The technique of esophageal SEMS placement is simple and can be rapidly mastered. Patients with ERFs have a respiratory shunt that makes intubation difficult and is often avoided. Restoring oral feeding increased the patient quality of life. SEMS placement is generally safe, but has few associated postoperative complications.

A single, clinically relevant dose of the GABAB agonist baclofen impairs visuomotor learning

KEY POINTS

Baclofen is a GABA_B agonist prescribed as a treatment for spasticity in stroke, brain injury and multiple sclerosis patients, who are often undergoing concurrent motor rehabilitation. Decreasing GABAergic inhibition is a key feature of motor learning and so there is a possibility that GABA agonist drugs, such as baclofen, could impair these processes, potentially impacting rehabilitation. Here, we examined the effect of 10 mg of baclofen, in 20 young healthy individuals, and found that the drug impaired retention of visuomotor learning with no significant effect on motor sequence learning. Overall baclofen did not alter transcranial magnetic stimulation-measured GABA_B inhibition, although the change in GABA_B inhibition correlated with aspects of visuomotor learning retention. Further work is needed to investigate whether taking baclofen impacts motor rehabilitation in patients.

ABSTRACT

The GABA_B agonist baclofen is taken daily as a treatment for spasticity by millions of stroke, brain injury and multiple sclerosis patients, many of whom are also undergoing motor rehabilitation. However, decreases in GABA are suggested to be a key feature of human motor learning, which raises questions about whether drugs increasing GABAergic activity may impair motor learning and rehabilitation. In this double-blind, placebo-controlled study, we investigated whether a single 10 mg dose of the GABA_B agonist baclofen impaired motor sequence learning and visuomotor learning in 20 young healthy participants of both sexes. Participants trained on visuomotor and sequence learning tasks using their right hand. Transcranial magnetic stimulation (TMS) measures of corticospinal excitability, GABA_A (short-interval intracortical inhibition_, 2.5 ms) and GABA_B (long-interval intracortical inhibition_, 150 ms) receptor activation were recorded from left M1. Behaviourally, baclofen caused a significant reduction of visuomotor aftereffect (F_1,137.8  = 6.133, P = 0.014) and retention (F_1,130.7  = 4.138, P = 0.044), with no significant changes to sequence learning. There were no overall changes to TMS measured GABAergic inhibition with this low dose of baclofen. This result confirms the causal importance of GABA_B inhibition in mediating visuomotor learning and suggests that chronic baclofen use could negatively impact aspects of motor rehabilitation.

Long-Term Deleterious Effects of Short-term Hyperoxia on Cancer Progression-Is Brain-Derived Neurotrophic Factor an Important Mediator? An Experimental Study

Perioperative factors promoting cancer recurrence and metastasis are under scrutiny. While oxygen toxicity is documented in several acute circumstances, its implication in tumor evolution is poorly understood. We investigated hyperoxia long-term effects on cancer progression and some underlying mechanisms using both in vitro and in vivo models of triple negative breast cancer (TNBC). We hypothesized that high oxygen exposure, even of short duration, may have long-term effects on cancer growth. Considering that hyperoxic exposure results in reactive oxygen species (ROS) formation, increased oxidative stress and increased Brain-Derived Neurotrophic Factor (BDNF) expression, BDNF may mediate hyperoxia effects offering cancer cells a survival advantage by increased angiogenesis and epithelial mesenchymal transition (EMT). Human breast epithelial MCF10A, human MDA-MB-231 and murine 4T1 TNBC were investigated in 2D in vitro system. Cells were exposed to normoxia or hyperoxia (40%, 60%, 80% O₂) for 6 h. We evaluated ROS levels, cell viability and the expression of BDNF, HIF-1α, VEGF-R2, Vimentin and E-Cadherin by immunofluorescence. The in vivo model consisted of 4T1 inoculation in Balb/c mice and tumor resection 2 weeks after and 6 h exposure to normoxia or hyperoxia (40%, 80% O₂). We measured lung metastases and the same molecular markers, immediately and 4 weeks after surgery. The in vitro study showed that short-term hyperoxia exposure (80% O₂) of TNBC cells increases ROS, increases BDNF expression and that promotes EMT and angiogenesis. The in vivo data indicates that perioperative hyperoxia enhances metastatic disease and this effect could be BDNF mediated.

Biosensor-based enzyme engineering approach applied to psicose biosynthesis

Bioproduction of chemical compounds is of great interest for modern industries, as it reduces their production costs and ecological impact. With the use of synthetic biology, metabolic engineering and enzyme engineering tools, the yield of production can be improved to reach mass production and cost-effectiveness expectations. In this study, we explore the bioproduction of D-psicose, also known as D-allulose, a rare non-toxic sugar and a sweetener present in nature in low amounts. D-psicose has interesting properties and seemingly the ability to fight against obesity and type 2 diabetes. We developed a biosensor-based enzyme screening approach as a tool for enzyme selection that we benchmarked with the Clostridium cellulolyticum D-psicose 3-epimerase for the production of D-psicose from D-fructose. For this purpose, we constructed and characterized seven psicose responsive biosensors based on previously uncharacterized transcription factors and either their predicted promoters or an engineered promoter. In order to standardize our system, we created the Universal Biosensor Chassis, a construct with a highly modular architecture that allows rapid engineering of any transcription factor-based biosensor. Among the seven biosensors, we chose the one displaying the most linear behavior and the highest increase in fluorescence fold change. Next, we generated a library of D-psicose 3-epimerase mutants by error-prone PCR and screened it using the biosensor to select gain of function enzyme mutants, thus demonstrating the framework's efficiency.

Leptin and adiponectin dynamics at patients with rectal neoplasm - Gender differences

Background

Numerous studies associate adipokines with colorectal malignancy, but few data deal with patients suffering exclusively of rectal carcinoma (RC).

Aims

We evaluated leptin and adiponectin levels in RC patients compared to healthy population and their dynamics after surgery.

Material and methods

Serum leptin and adiponectin were evaluated before surgery in 59 RC consecutive patients (38 males and 21 females), and in age and weight matched healthy controls. Measurements were repeated at 24, 72 hours and 7 days after surgery.

Results

Adipokine levels were higher in women. Controls had higher leptin (32.±4.34 vs 9.51±1.73 ng/ml in women and 11±2.66 vs 2.54±0.39 ng/ml in men, p = 0.00048 and 0.0032) and lower adiponectin (9±0.64 vs 11.85±1.02 μg/ml in women and 7.39±0.51 vs 8.5±0.62 μg/ml in men, p = 0.017 and 0.019) than RC patients. Surgery caused an increase of leptin from 5.11±0.8 to 18.7±2.42 ng/ml, p = 6.85 x 10¨⁸, and a decrease of adiponectin from 9.71±0.58 to 7.87±0.47 μg/ml, p = 1.4 x 10¨¹⁰ for all RC patients and returned thereafter to the initial range at 7 days. Adipokines were correlated with body weight (BW). The significance of correlation persisted after surgery only in males, but disappeared in females. Adipokines were not modified by tumor position, presurgical chemoradiotherapy or surgical technique. Women with RC experiencing weight loss had higher adiponectin than women without weight modifications (p<0.05 at all time points).

Conclusions

Adipokine levels of patients with RC differ from the healthy population, possibly reflecting an adaptation to disease. Adipokine modifications after surgery may be related to acute surgical stress. Whether leptin and adiponectin directly interact is not clear. Women have higher adipokine levels, more so after significant weight loss, but the strength of their correlation with BW decreases after surgery. These data suggest gender differences in the adipokine profile of RC patients which may find clinical applications.

Optimizing Cell-Free Biosensors to Monitor Enzymatic Production

Cell-free systems are promising platforms for rapid and high-throughput prototyping of biological parts in metabolic engineering and synthetic biology. One main limitation of cell-free system applications is the low fold repression of transcriptional repressors. Hence, prokaryotic biosensor development, which mostly relies on repressors, is limited. In this study, we demonstrate how to improve these biosensors in cell-free systems by applying a transcription factor (TF)-doped extract, a preincubation strategy with the TF plasmid, or reinitiation of the cell-free reaction (two-step cell-free reaction). We use the optimized biosensor to sense the enzymatic production of a rare sugar, D-psicose. This work provides a methodology to optimize repressor-based systems in cell-free to further increase the potential of cell-free systems for bioproduction.

VARIATIONS OF ADIPOKINE PROFILE IN PATIENTS DIAGNOSED WITH RECTAL CARCINOMA

BACKGROUND

Adipokine secretion is influenced by various disease conditions.

PURPOSE

We wanted to check the impact of rectal carcinoma (RC) on adipokine profile.

PATIENTS AND METHODS

We evaluated serum leptin and adiponectin levels in 24 RC patients (12 males and 12 females) as well as in the same number of age, sex and weight-matched healthy controls.

RESULTS

Adipokines were oppositely correlated with body weight (BW) in controls and RC patients. Women had higher adipokine levels than men. Healthy controls had higher leptin (37.6.±7.8 vs. 7.9±2.6 ng/mL in women and 11.9±4.6 vs. 1.4±0.34 ng/mL in men, p=0.0016 and 0.043) and lower adiponectin levels (9.3±1.1 vs. 14.9±1.1 µg/mL in women and 7.9±0.9 vs. 11.1±0.9 µg/mL in men, p=0.012 and 0.017) than RC patients.

CONCLUSION

Adipokine profiles of patients with RC differ from the healthy population, possibly reflecting an adaptation to the disease rather than a triggering factor. These differences may find clinical applications for the prognosis of disease evolution.

Bio-electrical impedance analysis for perioperative fluid evaluation in open major abdominal surgery

Water retention and intercompartmental redistribution occur frequently in association with adverse postoperative outcomes, yet the available strategies for non-invasive assessment are limited. One such approach for evaluating body water composition in various circumstances is bio-electrical impedance analysis (BIA). This study aims to appraise the usefulness of the Body Composition Monitor (BCM, Fresenius Medical Care, Germany) in assessing body fluid composition and intercompartmental shifts before and after open major abdominal surgery. This prospective, clinician blinded observational study enrolled all the patients scheduled consecutively for elective major open abdominal surgery during a 1-year period starting from January 1st, 2016. BIA parameters—total body water (TBW), extracellular water (ECW), intracellular water (ICW), absolute fluid overload (AFO), and relative fluid overload (RFO) were measured before and after surgery. The results were compared with fluid balance and outcome parameters such as organ dysfunction, ICU-and hospital length of stay (-LOS). The study population included 71 patients aged 60.2 ± 12 of whom 60.6% men and with a BMI of 26.3 ± 5.1 kg/m². Postoperative acute kidney injury, respiratory dysfunction, and infections occurred in 14.0%, 19.7% and 28.1% of cases, respectively. The median LOS in ICU was 20 h and the hospital-LOS was 10 days. Positive intraoperative fluid balance (2.4 ± 1.0 L) resulted in a significant increase of TBW (1.4 ± 2.4 L) and of ECW (1.4 ± 1.2 L). Intraoperative fluid balance significantly correlated with TBW change (r = 0.23, p = 0.04) and with AFO change (r = 0.31, p < 0.01). A significant correlation was found between pre- and postoperative AFO and RFO on one hand, and ICU-LOS on the other. BIA may be a useful tool for the perioperative assessment of volume status.

Lung Ultrasound Guided Fluid Management Protocol for the Critically Ill Patient: study protocol for a multi-centre randomized controlled trial

Background

In routine intensive care unit (ICU) practice, fluids are often administered without a safety limit, which may lead to fluid overload and decreased survival. Recently, B-lines score (BLS) has been validated as a lung ultrasound (LUS) quantification of pulmonary congestion. This suggests that LUS may provide a safety threshold to conduct fluid therapy and to avoid overhydration. However, there is no randomized study to test the utility of LUS in guiding fluid management in ICU patients by using a pre-specified BLS cut-off value as a threshold for fluid removal.

Methods

LUS Guided Fluid Management Protocol for the Critically Ill Patient is a prospective, multi-centre, randomized controlled trial. Five hundred ICU patients will be randomly assigned in a 1:1 ratio, to protocolized LUS-based fluid management or usual care. The trial intervention will start on ICU admission and will consist in daily assessment of BLS and triggered evacuation of excessive fluids with loop diuretics (Furosemide) when BLS ≥ 15. If rebalancing volume status with diuretics fails, forced evacuation by ultrafiltration will be used. The main endpoint is death from all causes at 28 days from randomization. The secondary outcomes are presence and time-course evolution of organ dysfunctions, ICU- and hospital length of stay, all-cause mortality at 90 days, and health economics data.

Discussion

If study results will show that LUS guided fluid management protocol improves outcome in ICU patients, it will be the base for other studies to refine this protocol or track those categories of critically ill patients to whom it may bring maximum benefits.

Trial registration

ClinicalTrials.gov, NCT03393065. Registered on 8 January 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3345-0) contains supplementary material, which is available to authorized users.

Subterranean Clover Stunt Virus Revisited: Detection of Two Missing Genome Components

Subterranean clover stunt virus (SCSV) is a type species of the genus Nanovirus in the family Nanoviridae. It was the first single-stranded DNA plant virus with a multipartite genome, of which genomic DNA sequences had been determined. All nanoviruses have eight genome components except SCSV, for which homologs of two genome components present in all other nanovirus genomes, DNA-U2 and DNA-U4, were lacking. We analysed archived and more recent samples from SCSV-infected legume plants to verify its genome composition and found the missing genome components. These results indicated that SCSV also has eight genome components and is a typical member of the genus Nanovirus.

Optimisation of Perioperative Cardiovascular Management to Improve Surgical Outcome II (OPTIMISE II) trial: study protocol for a multicentre international trial of cardiac output-guided fluid therapy with low-dose inotrope infusion compared with usual care in patients undergoing major elective gastrointestinal surgery

INTRODUCTION

Postoperative morbidity and mortality in older patients with comorbidities undergoing gastrointestinal surgery are a major burden on healthcare systems. Infections after surgery are common in such patients, prolonging hospitalisation and reducing postoperative short-term and long-term survival. Optimal management of perioperative intravenous fluids and inotropic drugs may reduce infection rates and improve outcomes from surgery. Previous small trials of cardiac-output-guided haemodynamic therapy algorithms suggested a modest reduction in postoperative morbidity. A large definitive trial is needed to confirm or refute this and inform widespread clinical practice.

METHODS

The Optimisation of Perioperative Cardiovascular Management to Improve Surgical Outcome II (OPTIMISE II) trial is a multicentre, international, parallel group, open, randomised controlled trial. 2502 high-risk patients undergoing major elective gastrointestinal surgery will be randomly allocated in a 1:1 ratio using minimisation to minimally invasive cardiac output monitoring to guide protocolised administration of intravenous fluid combined with low-dose inotrope infusion, or usual care. The trial intervention will be carried out during and for 4 hours after surgery. The primary outcome is postoperative infection of Clavien-Dindo grade II or higher within 30 days of randomisation. Participants and those delivering the intervention will not be blinded to treatment allocation; however, outcome assessors will be blinded when feasible. Participant recruitment started in January 2017 and is scheduled to last 3 years, within 50 hospitals worldwide.

ETHICS/DISSEMINATION

The OPTIMISE II trial has been approved by the UK National Research Ethics Service and has been approved by responsible ethics committees in all participating countries. The findings will be disseminated through publication in a widely accessible peer-reviewed scientific journal.

TRIAL REGISTRATION NUMBER

ISRCTN39653756.

Use of failure-to-rescue to identify international variation in postoperative care in low-, middle- and high-income countries: a 7-day cohort study of elective surgery

Background

The incidence and impact of postoperative complications are poorly described. Failure-to-rescue, the rate of death following complications, is an important quality measure for perioperative care but has not been investigated across multiple health care systems.

Methods

We analysed data collected during the International Surgical Outcomes Study, an international 7-day cohort study of adults undergoing elective inpatient surgery. Hospitals were ranked by quintiles according to surgical procedural volume (Q1 lowest to Q5 highest). For each quintile we assessed in-hospital complications rates, mortality, and failure-to-rescue. We repeated this analysis ranking hospitals by risk-adjusted complication rates (Q1 lowest to Q5 highest).

Results

A total of 44 814 patients from 474 hospitals in 27 low-, middle-, and high-income countries were available for analysis. Of these, 7508 (17%) developed one or more postoperative complication, with 207 deaths in hospital (0.5%), giving an overall failure-to-rescue rate of 2.8%. When hospitals were ranked in quintiles by procedural volume, we identified a three-fold variation in mortality (Q1: 0.6% vs Q5: 0.2%) and a two-fold variation in failure-to-rescue (Q1: 3.6% vs Q5: 1.7%). Ranking hospitals in quintiles by risk-adjusted complication rate further confirmed the presence of important variations in failure-to-rescue, indicating differences between hospitals in the risk of death among patients after they develop complications.

Conclusions

Comparison of failure-to-rescue rates across health care systems suggests the presence of preventable postoperative deaths. Using such metrics, developing nations could benefit from a data-driven approach to quality improvement, which has proved effective in high-income countries.

Nanovirus DNA-N encodes a protein mandatory for aphid transmission

Nanoviruses possess a multipartite single-stranded DNA genome and are naturally transmitted to plants by various aphid species in a circulative non-propagative manner. Using the cloned genomic DNAs of faba bean necrotic stunt virus (FBNSV) for reconstituting nanovirus infections we analyzed the necessity of different virus components for infection and transmission by aphids. We found that in the absence of DNA-U1 and DNA-U2 symptom severity decreased, and in the absence of DNA-U1 the transmission efficiency decreased. Most significantly, we demonstrated that the protein encoded by DNA-N (NSP) is mandatory for aphid transmission. Moreover, we showed that the NSP of FBNSV could substitute for that of a distantly related nanovirus, pea necrotic yellow dwarf virus. Altering the FBNSV NSP by adding 13 amino acids to its carboxy-terminus resulted in an infectious but non-transmissible virus. We demonstrate that the NSP acts as a nanovirus transmission factor, the existence of which had been hypothesized earlier.

Semisupervised Gaussian Process for Automated Enzyme Search

Synthetic biology is today harnessing the design of novel and greener biosynthesis routes for the production of added-value chemicals and natural products. The design of novel pathways often requires a detailed selection of enzyme sequences to import into the chassis at each of the reaction steps. To address such design requirements in an automated way, we present here a tool for exploring the space of enzymatic reactions. Given a reaction and an enzyme the tool provides a probability estimate that the enzyme catalyzes the reaction. Our tool first considers the similarity of a reaction to known biochemical reactions with respect to signatures around their reaction centers. Signatures are defined based on chemical transformation rules by using extended connectivity fingerprint descriptors. A semisupervised Gaussian process model associated with the similar known reactions then provides the probability estimate. The Gaussian process model uses information about both the reaction and the enzyme in providing the estimate. These estimates were validated experimentally by the application of the Gaussian process model to a newly identified metabolite in Escherichia coli in order to search for the enzymes catalyzing its associated reactions. Furthermore, we show with several pathway design examples how such ability to assign probability estimates to enzymatic reactions provides the potential to assist in bioengineering applications, providing experimental validation to our proposed approach. To the best of our knowledge, the proposed approach is the first application of Gaussian processes dealing with biological sequences and chemicals, the use of a semisupervised Gaussian process framework is also novel in the context of machine learning applied to bioinformatics. However, the ability of an enzyme to catalyze a reaction depends on the affinity between the substrates of the reaction and the enzyme. This affinity is generally quantified by the Michaelis constant KM. Therefore, we also demonstrate using Gaussian process regression to predict KM given a substrate-enzyme pair.

Point prevalence of surgical checklist use in Europe: relationship with hospital mortality

BACKGROUND

The prevalence of use of the World Health Organization surgical checklist is unknown. The clinical effectiveness of this intervention in improving postoperative outcomes is debated.

METHODS

We undertook a retrospective analysis of data describing surgical checklist use from a 7 day cohort study of surgical outcomes in 28 European nations (European Surgical Outcomes Study, EuSOS). The analysis included hospitals recruiting >10 patients and excluding outlier hospitals above the 95th centile for mortality. Multivariate logistic regression and three-level hierarchical generalized mixed models were constructed to explore the relationship between surgical checklist use and hospital mortality. Findings are presented as crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of 45 591 patients from 426 hospitals were included in the analysis. A surgical checklist was used in 67.5% patients, with marked variation across countries (0-99.6% of patients). Surgical checklist exposure was associated with lower crude hospital mortality (OR 0.84, CI 0.75-0.94; P=0.002). This effect remained after adjustment for baseline risk factors in a multivariate model (adjusted OR 0.81, CI 0.70-0.94; P<0.005) and strengthened after adjusting for variations within countries and hospitals in a three-level generalized mixed model (adjusted OR 0.71, CI 0.58-0.85; P<0.001).

CONCLUSIONS

The use of surgical checklists varies across European nations. Reported use of a checklist was associated with lower mortality. This observation may represent a protective effect of the surgical checklist itself, or alternatively, may be an indirect indicator of the quality of perioperative care.

CLINICAL TRIAL REGISTRATION

The European Surgical Outcomes Study is registered with ClinicalTrials.gov, number NCT01203605.

Validation of RetroPath, a computer-aided design tool for metabolic pathway engineering

Metabolic engineering has succeeded in biosynthesis of numerous commodity or high value compounds. However, the choice of pathways and enzymes used for production was many times made ad hoc, or required expert knowledge of the specific biochemical reactions. In order to rationalize the process of engineering producer strains, we developed the computer-aided design (CAD) tool RetroPath that explores and enumerates metabolic pathways connecting the endogenous metabolites of a chassis cell to the target compound. To experimentally validate our tool, we constructed 12 top-ranked enzyme combinations producing the flavonoid pinocembrin, four of which displayed significant yields. Namely, our tool queried the enzymes found in metabolic databases based on their annotated and predicted activities. Next, it ranked pathways based on the predicted efficiency of the available enzymes, the toxicity of the intermediate metabolites and the calculated maximum product flux. To implement the top-ranking pathway, our procedure narrowed down a list of nine million possible enzyme combinations to 12, a number easily assembled and tested. One round of metabolic network optimization based on RetroPath output further increased pinocembrin titers 17-fold. In total, 12 out of the 13 enzymes tested in this work displayed a relative performance that was in accordance with its predicted score. These results validate the ranking function of our CAD tool, and open the way to its utilization in the biosynthesis of novel compounds.

Genome diversity and evidence of recombination and reassortment in nanoviruses from Europe

The recent identification of a new nanovirus, pea necrotic yellow dwarf virus, from pea in Germany prompted us to survey wild and cultivated legumes for nanovirus infections in several European countries. This led to the identification of two new nanoviruses: black medic leaf roll virus (BMLRV) and pea yellow stunt virus (PYSV), each considered a putative new species. The complete genomes of a PYSV isolate from Austria and three BMLRV isolates from Austria, Azerbaijan and Sweden were sequenced. In addition, the genomes of five isolates of faba bean necrotic yellows virus (FBNYV) from Azerbaijan and Spain and those of four faba bean necrotic stunt virus (FBNSV) isolates from Azerbaijan were completely sequenced, leading to the first identification of FBNSV occurring in Europe. Sequence analyses uncovered evolutionary relationships, extensive reassortment and potential remnants of mixed nanovirus infections, as well as intra- and intercomponent recombination events within the nanovirus genomes. In some virus isolates, diverse types of the same genome component (paralogues) were observed, a type of genome complexity not described previously for any member of the family Nanoviridae. Moreover, infectious and aphid-transmissible nanoviruses from cloned genomic DNAs of FBNYV and BMLRV were reconstituted that, for the first time, allow experimental reassortments for studying the genome functions and evolution of these nanoviruses.

Efficacy and safety of anidulafungin in elderly, critically ill patients with invasive Candida infections: a post hoc analysis

Post hoc analysis of a non-comparative, prospective, multicentre, phase IIIb study was performed to compare efficacy and safety of anidulafungin in elderly (≥65 years) versus non-elderly (<65 years) Intensive Care Unit (ICU) patients with candidaemia/invasive candidiasis (C/IC). Adult ICU patients with confirmed C/IC meeting ≥1 of the following criteria were enrolled: post-abdominal surgery; solid tumour; renal/hepatic insufficiency; solid organ transplantation; neutropenia; age ≥65 years. Patients received anidulafungin (200 mg on Day 1, 100 mg/day thereafter) for ≥10 days followed by optional azole step-down therapy for a total treatment duration of 14-56 days. The primary efficacy endpoint was global (clinical and microbiological) response at the end of all therapy (EOT). Primary efficacy analysis was performed in the modified intent-to-treat (mITT) population (n=170), excluding unknown and missing responses. In total, 80 patients (47.1%) were aged ≥65 years and 90 (52.9%) were aged <65 years; the mean age difference between the two groups was 21.9 years. Global success at EOT in mITT patients was similar in elderly (68.1%) and non-elderly (70.7%) patients (P=0.719). However, global success rates were significantly lower in elderly versus non-elderly patients at 2 and 6 weeks after EOT (P=0.045 and P=0.016, respectively). Ninety-day survival was significantly lower (P=0.006) for elderly (42.8%) versus non-elderly patients (63.3%). The incidence and profile of adverse events were similar in elderly and non-elderly patients. Anidulafungin was effective and safe for treatment of C/IC in elderly ICU patients, despite higher baseline severity of illness scores.

Anidulafungin for the treatment of candidaemia/invasive candidiasis in selected critically ill patients

A prospective, multicentre, phase IIIb study with an exploratory, open-label design was conducted to evaluate efficacy and safety of anidulafungin for the treatment of candidaemia/invasive candidiasis (C/IC) in specific ICU patient populations. Adult ICU patients with confirmed C/IC meeting ≥1 of the following criteria were enrolled: post-abdominal surgery, solid tumour, renal/hepatic insufficiency, solid organ transplant, neutropaenia, and age ≥65 years. Patients received anidulafungin (200 mg on day 1, 100 mg/day thereafter) for 10–42 days, optionally followed by oral voriconazole/fluconazole. The primary efficacy endpoint was global (clinical and microbiological) response at the end of all therapy (EOT). Secondary endpoints included global response at the end of intravenous therapy (EOIVT) and at 2 and 6 weeks post-EOT, survival at day 90, and incidence of adverse events (AEs). The primary efficacy analysis was performed in the modified intent-to-treat (MITT) population, excluding unknown/missing responses. The safety and MITT populations consisted of 216 and 170 patients, respectively. The most common pathogens were Candida albicans (55.9%), C. glabrata (14.7%) and C. parapsilosis (10.0%). Global success was 69.5% (107/154; 95% CI, 61.6–76.6) at EOT, 70.7% (111/157) at EOIVT, 60.2% (77/128) at 2 weeks post-EOT, and 50.5% (55/109) at 6 weeks post-EOT. When unknown/missing responses were included as failures, the respective success rates were 62.9%, 65.3%, 45.3% and 32.4%. Survival at day 90 was 53.8%. Treatment-related AEs occurred in 33/216 (15.3%) patients, four (1.9%) of whom had serious AEs. Anidulafungin was effective, safe and well tolerated for the treatment of C/IC in selected groups of ICU patients.

Engineering antibiotic production and overcoming bacterial resistance

Progress in DNA technology, analytical methods and computational tools is leading to new developments in synthetic biology and metabolic engineering, enabling new ways to produce molecules of industrial and therapeutic interest. Here, we review recent progress in both antibiotic production and strategies to counteract bacterial resistance to antibiotics. Advances in sequencing and cloning are increasingly enabling the characterization of antibiotic biosynthesis pathways, and new systematic methods for de novo biosynthetic pathway prediction are allowing the exploration of the metabolic chemical space beyond metabolic engineering. Moreover, we survey the computer-assisted design of modular assembly lines in polyketide synthases and non-ribosomal peptide synthases for the development of tailor-made antibiotics. Nowadays, production of novel antibiotic can be tranferred into any chosen chassis by optimizing a host factory through specific strain modifications. These advances in metabolic engineering and synthetic biology are leading to novel strategies for engineering antimicrobial agents with desired specificities.

Functional improvement between brain death declaration and organ harvesting

INTRODUCTION

The quality of harvested organs is crucial for graft survival and for posttransplant evolution. This study sought to investigate the evolution of the functional status of brain death (BD) patients during the period between declaration and organ harvesting (BD duration).

MATERIALS AND METHODS

The study included all BD patients who underwent organ harvesting between January 2006 and June 2009. We compared the functional status regarding hemodynamics, respiration, kidney and liver function, coagulation, water, electrolytes, and acid-base balance evaluated at the moment of BD declaration (P1) and just before organ harvesting (P2). The results of the comparison were expressed as improvement, stable, or aggravation. We calculated mean values of the functional parameters in P1 and P2 and the statistical significance of the differences.

RESULTS

Twelve BD patients were included in the study. The time interval between P1 and P2 was 16.08 +/- 8.54 hours (range, 6-32). The number of patients with vasopressor support was 9/12 at P1 and 0/12 at P2, oxygenation disturbances 1/12 in P1 and 0/12 in P2, renal dysfunction 9/12 in P1 and 2/12 in P2, liver dysfunction 7/12 in P1 and 1/12 in P2, coagulopathy 4/12 in P1 and 0/12 in P2, hypernatremia 8/12 in P1 and 3/12 in P2, and metabolic acidosis 9/12 in P1 and 1/12 in P2. The overall assessment showed improvement in all patients. The most statistically significant improvement was registered in the cardiovascular, respiratory, renal, liver, and acid-base status (P < .05).

CONCLUSION

With early, aggressive, protocolized donor management, functional improvement may be achieved during BD duration.

Presumed consent for organ donation: is Romania prepared for it?

INTRODUCTION

In November 2007, a legislative initiative regarding the presumed consent for organ donation was proposed for parliamentary debate in Romania and was followed by public debate. The study aimed to asses public opinions expressed in the Romanian media.

MATERIALS AND METHODS

An Internet search was made. The pro and con reasons, the affiliation of parts involved in the debate and suggested future direction of action were identified.

RESULTS

The Internet search had 8572 results. The parts involved in the pro and con debate consisted of governmental structures, physicians, ethicists, politicians, media, religious authorities, nongovernmental associations, and lay persons. The main pros were the low rate of organ donation and the long waiting lists, enhancement of organ procurement, avoidance of wasting valuable organs, avoiding responsibility, and the stress imposed to the family in giving the donation consent, humanitarian purposes (saving lives), going along with the scientific progress, and less bureaucracy. The main cons were an unethical issue, violation of human rights, denial of brain death, unethical advantage of public ignorance, unethical use of underprivileged people, little results in terms of organ procurement, but huge negative effects on public opinion, public mistrust in transplant programs and impossibility of refusal identification due to particularities of the Romanian medical system.

CONCLUSION

The con opinions prevailed. For the moment, Romania seems to be unprepared to accept presumed consent. A future change in public perception regarding organ transplantation may modify the terms of a public debate.

First Report of a Nanovirus Disease of Pea in Germany

During the growing season of 2009, a disease consisting of leaf rolling, top yellows, and plant stunting affected pea (Pisum sativum) in fields near Aschersleben, Saxony-Anhalt, Germany. Samples from symptomatic plants collected in July 2009 were analyzed at the JKI in Braunschweig for infections by various legume viruses by ELISA, immunoelectron microscopy, and transmission assays by sap and aphids. Of 23 samples, 9 were shown to contain Pea enation mosaic virus and three samples each contained Bean leafroll virus and Soybean dwarf virus. From two further samples that had tested negative for the aforementioned viruses, we succeeded in transferring a disease agent to faba bean (Vicia faba) seedlings by giving 50 to 100 individuals of the pea aphid (Acyrthosiphon pisum) acquisition and inoculation access feedings each of ~48 h. Following vector transmission, the agent caused severe yellowing and stunting in pea and faba bean, sometimes followed by necrosis. Attempts at mechanical transmission of the agent failed, and isolation of double-stranded RNA from infected tissue was not successful. Therefore, we considered the possible presence of a nanovirus (4). When using polyclonal antibodies (PAbs) against Faba bean necrotic yellows virus (FBNYV) for double-antibody sandwich (DAS)-ELISA analysis of the two isolates of the disease agent we observed weak but clearly positive reactions. To confirm these weak DAS-ELISA reactions, we used all available monoclonal antibodies (MAbs) raised against FBNYV (1) and faba bean necrotic stunt virus (FBNSV) (3) individually in triple-antibody sandwich (TAS)-ELISA in combination with the FBNYV PAbs for plate coating. Six of 26 MAbs reacted from weak to strong with the two pea isolates, with MAbs FBNYV-3-1F7 and FBNSV-5-1G8 giving the strongest reactions and none of the MAbs giving a differential reaction with the two pea isolates. Employing rolling circle amplification of total DNA extracted from symptomatic leaves of one of the pea isolates yielded a substantial amount of high molecular weight DNA, whereas little or no amplification occurred when using DNA from noninoculated pea leaves. Restriction of the amplified DNA in a nanovirus iteron-specific manner by AatII endonuclease yielded a predominant and abundant product of ~1 kb (3). Sequence comparisons of eight cloned DNAs of 1,002 nucleotides long unequivocally identified them as complete DNA-R component of a new member of the genus Nanovirus (2,4). Its DNA-R sequence (GenBank No. GU553134) is nearly equidistant from the DNA-R sequences of FBNYV (Y11405), FBNSV (GQ150778), Milk vetch dwarf virus (MDV) (AB027511) and Subterranean clover stunt virus (SCSV) (AJ290434), sharing with them respective sequence identities of 79, 78, 79, and 73%. Moreover, it is more distinct from the DNA-R sequences of FBNYV, FBNSV, and MDV than the three latter are from each other (86 to 91%). This together with the serological data relating to the capsid protein properties of this virus strongly suggest that it is distinct from the hitherto described nanoviruses FBNYV, MDV, FBNSV, and SCSV. Therefore, we propose the name pea necrotic yellow dwarf virus (PNYDV) for this new nanovirus naturally infecting pea in Germany. References: (1) A. Franz et al. Ann. Appl. Biol. 128:255, 1996. (2) I. Grigoras et al. J. Gen. Virol. 89:583, 2008. (3) I. Grigoras et al. J. Virol. 83:10778, 2009. (4) H. J. Vetten et al. Page 343 in: Virus Taxonomy. Elsevier/Academic Press, London, 2005.

Reconstitution of authentic nanovirus from multiple cloned DNAs

We describe a new plant single-stranded DNA (ssDNA) virus, a nanovirus isolate originating from the faba bean in Ethiopia. We applied rolling circle amplification (RCA) to extensively copy the individual circular DNAs of the nanovirus genome. By sequence analyses of more than 208 individually cloned genome components, we obtained a representative sample of eight polymorphic swarms of circular DNAs, each about 1 kb in size. From these heterogeneous DNA populations after RCA, we inferred consensus sequences of the eight DNA components of the virus genome. Based on the distinctive molecular and biological properties of the virus, we propose to consider it a new species of the genus Nanovirus and to name it faba bean necrotic stunt virus (FBNSV). Selecting a representative clone of each of the eight DNAs for transfer by T-DNA plasmids of Agrobacterium tumefaciens into Vicia faba plants, we elicited the development of the typical FBNSV disease symptoms. Moreover, we showed that the virus thus produced was readily transmitted by two different aphid vector species, Aphis craccivora and Acyrthosiphon pisum. This represents the first reconstitution of a fully infectious and sustainably insect-transmissible nanovirus from its cloned DNAs and provides compelling evidence that the genome of a legume-infecting nanovirus is typically comprised of eight distinct DNA components.

Transcripts encoding the nanovirus master replication initiator proteins are terminally redundant

The multicomponent single-stranded DNA plant nanoviruses encode unique master replication initiator (Rep) proteins. We have mapped the 5′ and 3′ termini of the corresponding polyadenylated mRNAs from faba bean necrotic yellows virus (FBNYV) and subterranean clover stunt virus and found that these are terminally redundant by up to about 160 nt. Moreover, the origin of viral DNA replication is transcribed into RNA that is capable of folding into extended secondary structures. Other nanovirus genome components, such as the FBNYV DNA encoding the protein Clink or an FBNYV DNA encoding a non-essential para-Rep protein, are not transcribed in such a unique fashion. Thus, terminally redundant mRNAs and the resulting transcription of the replication origin appear to be restricted to nanovirus master Rep DNAs. We speculate that this may be a way to regulate the expression of the essential master Rep protein.

Extracellular Production of Hydrogen Selenide Accounts for Thiol-assisted Toxicity of Selenite against Saccharomyces cerevisiae

Administration of selenium in humans has anticarcinogenic effects. However, the boundary between cancer-protecting and toxic levels of selenium is extremely narrow. The mechanisms of selenium toxicity need to be fully understood. In Saccharomyces cerevisiae, selenite in the millimolar range is well tolerated by cells. Here we show that the lethal dose of selenite is reduced to the micromolar range by the presence of thiols in the growth medium. Glutathione and selenite spontaneously react to produce several selenium-containing compounds (selenodiglutathione, glutathioselenol, hydrogen selenide, and elemental selenium) as well as reactive oxygen species. We studied which compounds in the reaction pathway between glutathione and sodium selenite are responsible for this toxicity. Involvement of selenodiglutathione, elemental selenium, or reactive oxygen species could be ruled out. In contrast, extracellular formation of hydrogen selenide can fully explain the exacerbation of selenite toxicity by thiols. Indeed, direct production of hydrogen selenide with D-cysteine desulfhydrase induces high mortality. Selenium uptake by S. cerevisiae is considerably enhanced in the presence of external thiols, most likely through internalization of hydrogen selenide. Finally, we discuss the possibility that selenium exerts its toxicity through consumption of intracellular reduced glutathione, thus leading to severe oxidative stress.

Ycf1p-dependent Hg(II) detoxification in Saccharomyces cerevisiae

In Saccharomyces cerevisiae, disruption of the YCF1 gene increases the sensitivity of cell growth to mercury. Transformation of the resulting ycf1 null mutant with a plasmid harbouring YCF1 under the control of the GAL promoter largely restores the wild-type resistance to the metal ion. The protective effect of Ycf1p against the toxicity of mercury is especially pronounced when yeast cells are grown in rich medium or in minimal medium supplemented with glutathione. Secretory vesicles from S. cerevisiae cells overproducing Ycf1p are shown to exhibit ATP-dependent transport of bis(glutathionato)mercury. Moreover, using beta-galactosidase as a reporter protein, a relationship between mercury addition and the activity of the YCF1 promoter can be shown. Altogether, these observations indicate a defence mechanism involving an induction of the expression of Ycf1p and transport by this protein of mercury-glutathione adducts into the vacuole. Finally, possible coparticipation in mercury tolerance of other ABC proteins sharing close homology with Ycf1p was investigated. Gene disruption experiments enable us to conclude that neither Bpt1p, Yor1p, Ybt1p nor YHL035p plays a major role in the detoxification of mercury.