A novel lipase with dual localisation in Trypanosoma brucei

Phospholipases are esterases involved in lipid catabolism. In pathogenic micro-organisms (bacteria, fungi, parasites) they often play a critical role in virulence and pathogenicity. A few phospholipases (PL) have been characterised so far at the gene and protein level in unicellular parasites including African trypanosomes (AT). They could play a role in different processes such as host–pathogen interaction, antigenic variation, intermediary metabolism. By mining the genome database of AT we found putative new phospholipase candidate genes and here we provided biochemical evidence that one of these has lipolytic activity. This protein has a unique non-canonical glycosome targeting signal responsible for its dual localisation in the cytosol and the peroxisomes-related organelles named glycosomes. We also show that this new phospholipase is excreted by these pathogens and that antibodies directed against this protein are generated during an experimental infection with T. brucei gambiense, a subspecies responsible for infection in humans. This feature makes this protein a possible tool for diagnosis.

Perioperative atrial fibrillation and risk of stroke after cardiac surgery: a systematic review and meta-analysis

Background

Perioperative atrial fibrillation (POAF) after cardiac surgery has been associated with an increased risk of stroke. However, many previous studies have not systematically excluded patients with pre-existing AF. As such, the association between new-onset POAF and stroke risk has not been well established.

Purpose

To perform a systematic review and meta-analysis on the short and long-term risks of stroke in patients experiencing new-onset POAF after cardiac surgery.

Methods

We searched MEDLINE, EMBASE, and the Cochrane Library databases for studies comparing the risk of stroke in patients with versus without new-onset POAF after cardiac surgery. Studies were included in our review if they enrolled ≥100 patients and defined POAF as new-onset AF in patients with no history of preoperative AF. Data were independently extracted in duplicate. The quality of studies was assessed using the Newcastle Ottawa Scale. Random-effects meta-analysis was used to calculate summary risk ratios. Short-term stroke risk was calculated using events occurring either in-hospital or ≤30 days after surgery, and long-term risk was calculated using events occurring >30 days after surgery.

Results

After reviewing 11,791 citations, 46 studies met the inclusion criteria. These studies included 364,822 patients, of which 76,388 (20.9%) developed new-onset POAF. The incidence of stroke was higher among patients with POAF versus no POAF (n=44 studies; incidence 2.76% vs. 1.53%; relative risk (RR) 1.91, 95% CI 1.65–2.23; I2 = 78%). A sensitivity analysis of high-quality studies alone yielded similar results (n=9 studies; RR 1.74, 95% CI 1.31–2.30; I2 = 88%). Patients with POAF had a higher incidence of stroke both in the short-term (n=35 studies; 2.71% vs. 1.36%; RR 2.13, 95% CI 1.81–2.51; I2 = 69%) and long-term (n=20 studies; 1.6 vs. 1.0 per 100 patient-years; RR 1.39, 95% CI 1.24–1.57; I2 = 27%). The risk of stroke was increased in POAF patients across all types of cardiac surgery performed, including isolated CABG (n=19 studies; RR 1.93, 95% CI 1.60–2.32; I2 = 62%), isolated transcatheter aortic valve implantation (n=7 studies; RR 1.86, 95% CI 1.32–2.63; I2 = 0%), and studies including multiple procedure types (n=16 studies; RR 1.90, 95% CI 1.44–2.51; I2 = 89%).

Conclusion

New-onset POAF after cardiac surgery is associated with an increased risk of stroke, both in the short and long term. The absolute risk difference is small, and randomized trials are needed to assess the efficacy and safety of treatment interventions in this patient population.

Funding Acknowledgement

Type of funding source: None

High-sensitivity troponin I predicts major cardiovascular events after noncardiac surgery

Background

Myocardial injury after noncardiac surgery (MINS) is common and is associated with postoperative major cardiac events and 30-day mortality. We have previously established the diagnostic criteria for MINS with the 4th-generation cardiac troponin T assay (TnT) and 5th-generation high-sensitivity TnT assay (hsTnT) based on prognostically relevant thresholds. Little is known about diagnostic criteria for MINS using the high-sensitivity troponin I (hsTnI) assay.

Purpose

To determine hsTnI thresholds associated with 30-day major cardiac events and death after noncardiac surgery.

Methods

We performed a nested prospective biobank cohort study of 4545 patients from the VISION Study. Patients were aged ≥45 years and underwent in-patient noncardiac surgery under regional or general anesthesia. Patients had samples collected and frozen preoperatively, and on postoperative days 1, 2 and 3. We measured hsTnI on thawed preoperative and postoperative samples. We used iterative Cox proportional hazard models to determine peak postoperative hsTnI thresholds independently associated with major cardiac events (i.e., composite of death, non-fatal cardiac arrest, congestive heart failure within 30 days and non-fatal myocardial infarction from postoperative days 4–30).

Results

Major cardiac events occurred in 89/4545 (2.0%) patients. Peak hsTnI values of <75 ng/L, 75 ng/L to <1000 ng/L, and ≥1000 ng/L were associated with an incidence of major cardiac events of 1.2% (95% CI 0.9–1.6), 7.1% (95% CI 4.8–10.5) and 25.9% (95% CI 16.3–38.4), respectively. Compared to peak hsTnI <75 ng/L (reference), hsTnI values 75 ng/L to <1000 ng/L and ≥1000 ng/L were associated with adjusted hazard ratios (aHR) of 4.53 (95% CI 2.75–7.48) and 16.17 (95% CI 8.70–30.07), respectively. No change from preoperative hsTnI to peak postoperative hsTnI significantly improved the model when included on top of the identified thresholds. Incidence of major cardiac events was 31/343 (9%) in patients with postoperative peak hsTnI ≥75 ng/L versus 52/4178 (1%) in patients with postoperative peak hsTnI <75 ng/L (aHR 5.76; 95% CI 3.64–9.11). A postoperative peak hsTnI ≥75 ng/L was associated with increased risk of major cardiac events either in the presence (aHR 9.35; 95% CI 5.28–16.55) or absence (aHR 3.99; 95% CI 2.19–7.25) of clinical features of myocardial injury (e.g., chest pain, ischemic electrocardiography changes).

Conclusion

A hsTnI elevation within the first 3 days after noncardiac surgery independently predicts major cardiac events at 30 days. A peak postoperative hsTnI ≥75 ng/L was associated with a 6-fold increase in the risk of subsequent major cardiac events at 30 days as compared to peak postoperative hsTnI<75 ng/L. This hsTnI threshold can be used to diagnose MINS.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Siemens Healthcare Diagnostics Inc. Canadian Institutes of Health Research

Vitamin K antagonists versus direct oral anticoagulants after cardiac surgery: a 31-country cohort study

Background

About 10% of patients undergoing cardiac surgery have a history of atrial fibrillation (AF). Among these patients, uncertainty exists regarding the safest and most effective oral anticoagulant (OAC) during the postoperative period.

Purpose

To evaluate practice patterns regarding OAC early after cardiac surgery in patients with a preoperative history of AF and to compare the safety and effectiveness of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs).

Methods

We conducted a nested cohort study within the Left Atrial Appendage Occlusion Study (LAAOS) III (NCT01561651). LAAOS III included patients with AF undergoing cardiac surgery with a CHA2DS2-VASC ≥2. In this substudy, we examined patients without end-stage renal dysfunction (eGFR >30 mL/min/1.73m2) who were discharged on OAC. We evaluated bleeding and thromboembolism within 90 days postoperatively using logistic regression adjusting for CHA2DS2-VASC score.

Results

Recruitment started in 2012 and completed in 2018 in 113 centres in 31 countries. Of the 4811 patients enrolled in LAAOS III, 3725 (77%) were included in this substudy. Preoperatively, 58% of patients received OAC: 56% DOACs and 44% VKAs. At hospital discharge 23% received DOACs and 77% VKAs; 55% of patients on a DOAC at baseline were switched to a VKA while 5% of patients on a VKA were switched to a DOAC. Patients discharged on a DOAC were older, had a higher CHA2DS2-VASC, and were more likely to be male. Patients having undergone an isolated coronary bypass procedure were more likely prescribed DOACs than VKAs (41% vs 23%, p<0.001) whereas isolated non-mechanical valve patients were more likely to be prescribed VKAs (43% vs 28%, p<0.001). Switching from a DOAC to a VKA postoperatively occurred in 42% of patients In Australia/New Zealand, 49% in Europe, and 63% in North America. Major bleeding between 48 hours postoperatively and 30 days occurred in 1.5% in the DOAC group and 1.3% in the VKA group (aOR 1.14, 95% CI 0.60–2.15, p=0.69) while between 48 hours and 90 days, it occurred in 1.8% of patients in both groups (aOR 0.97, 95% CI, 0.54–1.17, p=0.91). Cardiac tamponade, the composite of stroke and systemic arterial embolism, and the composite of stroke, systemic arterial embolism and death did not differ significantly at 30 and 90 days between the DOAC and VKA groups.

Conclusions

VKAs was the dominant OAC used early after cardiac surgery, but postoperative OAC practices varied by region. After adjustment for CHA2DS2-VASC score, the early postoperative incidence of major bleeding and of the composite of stroke and systemic arterial embolism did not differ significantly when DOACs were compared with VKAs.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): CIHR, Heart and Stroke Foundation

Incidental findings in CT imaging of coronary artery bypass grafts: results from a Canadian multicenter prospective cohort

Objective

To assess the prevalence and clinical significance of incidental findings identified during computed tomography imaging of coronary artery bypass grafts.

Results

This prospective study includes 144 patients undergoing coronary graft patency assessment using computed tomography. Incidental findings were classified as significant if they were considered to need an immediate action or treatment, short-term work-up or follow-up, or minor. A total of 211 incidental findings were present in 109 (75.7%) patients. Seventy-one incidental findings (33.6%) were cardiac and 140 (66.4%) were extracardiac. Most common cardiac incidental findings were atrial dilatation [39 patients, 48 incidental findings (67.6%)] and aortic valve calcifications (7 patients, 9.9%). Among the 140 extracardiac incidental findings, the most common were lung nodules (51 patients, 54 nodules, 38.6%), and emphysema (21 patients, 15%). Thirty-six (25.7%) extracardiac incidental findings were significant and notably, 23 (63.9%) were lung nodules. Follow-up was recommended in 37 cases, among which all patients with significant lung nodules (23 patients, 62.2%). In conclusion, most common computed tomography incidental findings in patients with coronary grafts were lung nodules and emphysema.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3168-1) contains supplementary material, which is available to authorized users.

Long-Term Follow-Up of Outcomes With F-18-Fluorodeoxyglucose Positron Emission Tomography Imaging–Assisted Management of Patients With Severe Left Ventricular Dysfunction Secondary to Coronary Disease

Background—

Whether viability imaging can impact long-term patient outcomes is uncertain. The PARR-2 study (Positron Emission Tomography and Recovery Following Revascularization) showed a nonsignificant trend toward improved outcomes at 1 year using an F-18-fluorodeoxyglucose positron emission tomography (PET)–assisted strategy in patients with suspected ischemic cardiomyopathy. When patients adhered to F-18-fluorodeoxyglucose PET recommendations, outcome benefit was observed. Long-term outcomes of viability imaging–assisted management have not previously been evaluated in a randomized controlled trial.

Methods and Results—

PARR-2 randomized patients with severe left ventricular dysfunction and suspected CAD being considered for revascularization or transplantation to standard care (n= 195) versus PET-assisted management (n=197) at sites participating in long-term follow-up. The predefined primary outcome was time to composite event (cardiac death, myocardial infarction, or cardiac hospitalization). After 5 years, 105 (53%) patients in the PET arm and 111 (57%) in the standard care arm experienced the composite event (hazard ratio for time to composite event =0.82 [95% confidence interval 0.62–1.07]; P =0.15). When only patients who adhered to PET recommendations were included, the hazard ratio for the time to primary outcome was 0.73 (95% confidence interval 0.54–0.99; P =0.042).

Conclusions—

After a 5-year follow-up in patients with left ventricular dysfunction and suspected CAD, overall, PET-assisted management did not significantly reduce cardiac events compared with standard care. However, significant benefits were observed when there was adherence to PET recommendations. PET viability imaging may be best applied when there is likely to be adherence to imaging-based recommendations.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00385242.

Community structure and nutrient level control the tolerance of autotrophic biofilm to silver contamination

Autotrophic biofilms are complex and fundamental biological compartments of many aquatic ecosystems. Since microbial species differ in their sensitivity to stressors, biofilms have long been proposed for assessing the quality of aquatic ecosystems. Among the many stressors impacting aquatic ecosystems, eutrophication and metal pollution are certainly the most common. Despite that these stressors often occur together, their effects on biofilms have been far much studied separately than interactively. In this study, we evaluated the interactive effects of silver (Ag), a reemerging contaminant, and phosphorus (P), a nutrient often associated with freshwater eutrophication, on the structure and functioning of two types of autotrophic biofilms, one dominated by diatoms and another one dominated by cyanobacteria. We hypothesized that P would alleviate the toxic effects of Ag, either directly, through the contribution of P in metal detoxification processes, or indirectly, through P-mediated shifts in biofilm community compositions and associated divergences in metal tolerance. Results showed that Ag impacted biofilm community structure and functioning but only at unrealistic concentrations (50 μg/L). P availability led to significant shifts in biofilm community composition, these changes being more pronounced in diatom- than those in cyanobacteria-dominated biofilm. In addition, P tended to reduce the impact of Ag but only for the cyanobacteria-dominated biofilm. More generally, our results highlight the preponderant role of the initial community structure and nutrient level on biofilm response to metallic pollutants.

Influence of the natural growth environment on the sensitivity of phototrophic biofilm to herbicide

Ecotoxicological experiments were performed in laboratory-scale microcosms to investigate community-level structural responses of river phototrophic biofilms from different environments to herbicide exposure. Biofilms were initially cultivated on artificial supports placed in situ for 4 weeks at two sites, site M, located in an agricultural watershed basin and site S, located in a forested watershed basin. The biofilms were subsequently transferred to microcosms and, after an acclimatisation phase of 7 days were exposed to alachlor at 10 and 30 μg L(-1) for 23 days. Alachlor effects were assessed by a combination of structural parameters, including biomass (ash-free dry mass and chlorophyll a), molecular fingerprinting of the bacterial community (polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE)) and diatom species composition. Alachlor impacted the chlorophyll a and ash-free dry mass levels of phototrophic biofilms previously cultivated at site S. The structural responses of bacterial and diatom communities were difficult to distinguish from changes linked to the microcosm incubation period. Phototrophic biofilms from site S exposed at 30 μg L(-1) alachlor were characterised by an increase of Achnanthidium minutissimum (K-z.) Czarnecki abundance, as well as a higher proportion of abnormal frustules. Thus, phototrophic biofilms with different histories, exhibited different responses to alachlor exposure demonstrating the importance of growth environment. These observations also confirm the problem of distinguishing changes induced by the stress of pesticide toxicity from temporal evolution of the community in the microcosm.

Cost implications of the use of basal insulin glargine in people with early dysglycemia: the ORIGIN trial

AIMS

The cost implications of the Outcome Reduction with an Initial Glargine Intervention (ORIGIN) trial were evaluated using a prespecified analysis plan.

METHODS

Purchasing power parity-adjusted country-specific costs were applied to consumed healthcare resources by participants from each country. Subgroup analyses were conducted on subgroups based on baseline metabolic status and diabetes duration.

RESULTS

The total undiscounted cost per participant in the insulin glargine arm was $13,491 ($13,080 to $14,254) versus $11,189 ($10,568 to $12,147) for standard care, an increase of $2303 ($1370 to $3235; p < 0.0001); the discounted increase was $2099 ($1276 to $2923; P < 0.0001). The greater number of mainly generic oral anti-diabetic agents in the standard group partially offset the higher cost of basal insulin glargine. As the trial progressed and the standard group required more anti-diabetic medications, the annual cost difference decreased, reaching $68 (-$160 to $295) in the last year. The subgroup whose baseline diabetes duration was ≥ 6 years achieved cost-savings during the trial.

CONCLUSIONS

From a global perspective basal insulin glargine use in ORIGIN incurred greater costs than standard care using older generic drugs. Nevertheless, the cost difference fell with time such that the intervention was cost-neutral by the last year.

Neuropathic complications after 157 procedures of continuous popliteal nerve block for hallux valgus surgery. A retrospective study

BACKGROUND

Continuous peripheral nerve block (CPNB), in particular at the popliteal fossa, is widely used in orthopedic surgery, allowing good postoperative analgesia. Possible neuropathic complications, however, remain poorly known.

OBJECTIVE

To review the characteristics of peripheral neuropathy (PN) after sciatic CPNB at the popliteal fossa, estimating prevalence, severity, evolution and possible risk factors, especially those relating to the procedure.

METHODS

Retrospective study of PN associated with popliteal fossa CPNB for hallux valgus surgery, between November 1st, 2005 and November 1st, 2009. All procedures were analyzed (type of anesthesia, approach, nerve location technique, number of procedures by operator) with, for each case of PN, analysis of clinical and electromyographic data.

RESULTS

One hundred and fifty seven sciatic CPNBs were performed (92% women; mean age, 55 years). The approach was lateral (n=62), posterior (n=74) or unknown (n=21). Ultrasound guidance was combined to neurostimulation for 69 patients (44%). Three women (prevalence=1.91%), aged 19, 24 and 65 years respectively, developed associated common superficial peroneal and sural nerve injury (2), axonal on electromyography, with motor (n=1) and/or sensory (n=3) residual dysfunction.

DISCUSSION

The higher prevalence found in the present study than in the literature (0 to 0.5%) raises questions of methodological bias or technical problems. The common peroneal and sural nerves seem to be exposed, unlike the tibial. Several mechanisms can be suggested: anesthetic neurotoxicity, direct mechanical lesion, or tourniquet-related ischemia and conduction block. Further studies are necessary to determine the ideal anesthetic procedure.

CONCLUSION

Patients should be informed of the potential risk, however rare, even during mild surgery. The best possible technique should be implemented, with reinforced surveillance.

A method to assess KRAS/BRAF genotype in patients with metastatic colorectal cancer (mCRC) elligible for anti-EGFR therapies

383

Background: KRAS/BRAF mutation screening is a new diagnostic tool since activating mutations, especially for KRAS, are strong negative predictive factors for anti-EGFR monoclonal antibody therapies. Therefore, standardized, reliable, and rapid mutation detection methods are needed. The goal of the present study is to evaluate the concordance between a clinically validated laboratory-developed KRAS/BRAF SNaPshot test and a novel research use assay, the Signature KRAS/BRAF Mutations kit (Asuragen Inc.), in representative clinical specimens.

Methods: Genomic DNA from FFPE mCRC specimens previously tested with the SNaPshot assay were analyzed using the Signature KRAS/BRAF mutations assay. The Signature assay consists of multiplex PCR followed by multiplex hybridization to fluorescent beads coupled to capture probes and detection on the Luminex analyzer. The qualitative assay detects 12 mutations in KRAS codons 12/13 and BRAF V600E based on the median fluorescence intensity (MFI) generated by each bead above (positive) or below (negative) a fixed cut off.

Results: To date, KRAS/BRAF mutational status was successfully assessed with the signature assay in 248 samples. After initial testing, signature and SNaPshot assays were in qualitative agreement for 232 samples (93.5%): 166 positive for KRAS, 46 positive for BRAF, and 20 double negative. 16 samples (6%) presented discrepant results: (i) 11 false negative samples with fluorescence signals for the expected mutations above the average assay background signal but below the 450 MFI positive cut off preselected for this study (330-431 MFI), (ii) 3 samples positive for both KRAS and BRAF and (iii) 2 false positive samples. 7 discrepant samples have been retested to date resulting in an overall agreement of 99.6% (239/240). However, different KRAS mutations were identified by the SNaPshot and signature assays in 3 positive samples.

Conclusions: The signature KRAS/BRAF mutations assay is an attractive method, easy to use, less time consuming than the SNaPshot assay, and potentially adaptable to routine clinical testing. Further analysis will establish and validate cut offs to be used in routine diagnostic procedures.

No significant financial relationships to disclose.

TP53 mutations in irinotecan-refractory KRAS wt-BRAF wt metastatic colorectal cancer patients treated with cetuximab-based chemotherapy

426

Background: Anti-EGFR antibodies are more efficient when EGFR pathway is activated without mutations on downstream effectors such as KRAS and BRAF (Lievre et al. Cancer Res. 2008 and Khambata-Ford et al. J Clin Oncol. 2007). Moreover, tumor growth from EGFR activation may required inactivation of the molecular brake p53 suggesting that anti-EGFR therapy should be more efficient if p53 is inactivated (Oden-Gangloff et al. Br J Cancer. 2008). The aim of the study was to evaluate, in an independent series, the impact of p53 mutations in irinotecan-refractory KRAS wt-BRAF wt MCRC patients treated with anti- EGFR.

Methods: A total of 100 MCRC patients treated with cetuximab-based CT were included. KRAS and BRAF mutational status were determined using SNaPshot or allelic discrimination methods. TP53 mutations within exons 5 to 8 were detected using direct sequencing. Response to cetuximab, based on RECIST criteria, was evaluated according to molecular analysis using the Fischer exact test. Progression- free survivals (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method and compared with log-rank test.

Results: Objective response (OR = partial and complete response) was observed in 40% and control disease (CD = OR+stable disease) in 74% of patients. Median PFS and OS was 12 weeks and 12 months, respectively. TP53 mutations were detected in 66% of patients and were not significantly associated with OR and CD. In contrast, patients with KRAS wt-BRAF wt and TP53 mutation had significantly longer PFS as compared to KRAS wt–BRAF wt and TP53 non mutated patients (32 weeks vs. 21 weeks, respectively; p = 0.01). There was a trend but not significant increased OS in patients with TP53 mutations (16 months vs. 13 months)

Conclusions: In this independent study, our results confirm that TP53 mutation was significantly associated with an increase PFS in irinotecan-refrcatory KRAS wt-BRAF wt MCRC patients treated with anti-EGFR.

[Table: see text]

[Proposal of a rating scale of posture for simple dysfunctional dysphonia: "S-TRAV"]

OBJECTIVE

This work aims to create a scale to evaluate posture, quick and easy to perform during the assessment of voice in patients with simple dysfunctional dysphonia.

MATERIAL AND METHOD

The "S-TRAV" scale was evaluated on 60 subjects with dysphonia and 60 control subjects. It assesses "the overall severity" of the alteration of posture, the "Tension", the "Breathing", the "Ground anchoring" and the "Verticality" both quantitatively (score 0-3) and qualitatively. The patient also assesses his voice disorder and his posture. Postural observation was carried out in five conditions: at rest, conversational voice, reading, projected voice and singing voice. The comparison between the dysphonic subjects and control subjects was used to assess the sensitivity of this tool. Two reviewers rated the scale to determine its reproducibility.

RESULTS

The scale is sensible for the majority of criteria with a significance coefficient less than 0.05. The most discriminate criteria relate to the cervical spine, the overall score of postural severity assessed by the therapist and verticality. All criteria have a low level of variability between the reviewers under all conditions. Most criteria are correlated with the criterion "Overall Severity" of postural alterations under all conditions. Non-sensible criteria were eliminated from the final scale).

CONCLUSION

This tool is sensitive, reproducible and relevant in assessing the severity of postural alterations and their location. Further studies will validate the scale on a consistent population.