Prospective validation of the EuroSCORE II risk model in a single Dutch cardiac surgery centre

Objective

The EuroSCORE I was one of the most frequently used pre-operative risk models in cardiac surgery. In 2011 it was replaced by its successor the EuroSCORE II. This study aims to validate the EuroSCORE II and to compare its performance with the EuroSCORE I in a Dutch hospital.

Methods

The EuroSCORE II was prospectively validated in 2,296 consecutive cardiac surgery patients between 1 April 2012 and 1 January 2014. Receiver operating characteristic curves on in-hospital mortality were plotted for EuroSCORE I and EuroSCORE II, and the area under the curve was calculated to assess discriminative power. Calibration was assessed by comparing observed versus expected mortality. Additionally, analyses were performed in which we stratified for type of surgery and for elective versus emergency surgery.

Results

The observed mortality was 2.4% (55 patients). The discriminative power of the EuroSCORE II surpassed that of the EuroSCORE I (area under the curve EuroSCORE II 0.871, 95% confidence interval (CI) 0.832–0.911; area under the curve additive EuroSCORE I 0.840, CI 0.798–0.882; area under the curve logistic EuroSCORE I 0.761, CI 0.695–0.828). Both the additive and the logistic EuroSCORE I overestimated mortality (predictive mortality additive EuroSCORE I median 5.0%, inter-quartile range 3.0–8.0%; logistic EuroSCORE I 10.7%, inter-quartile range 5.8–13.9), while the EuroSCORE II underestimated mortality (median 1.6%, inter-quartile range 1.0–3.5). In most stratified analyses the EuroSCORE II performed better.

Conclusion

Our results show that the EuroSCORE II produces a valid risk prediction and outperforms the EuroSCORE I in elective cardiac surgery patients.

     

The contributions of Ca2+, phospholipids and tissue-factor apoprotein to the activation of human blood-coagulation factor X by activated factor VII.

In the extrinsic pathway of blood coagulation, Factor X is activated by a complex of tissue factor, factor VII(a) and Ca2+ ions. Using purified human coagulation factors and a sensitive spectrophotometric assay for Factor Xa, we could demonstrate activation of Factor X by Factor VIIa in the absence of tissue-factor apoprotein, phospholipids and Ca2+. This finding allowed a kinetic analysis of the contribution of each of the cofactors. Ca2+ stimulated the reaction rate 10-fold at an optimum of 6 mM (Vmax. of 1.1 x 10(-3) min-1) mainly by decreasing the Km of Factor X (to 11.4 microM). In the presence of Ca2+, 25 microM-phospholipid caused a 150-fold decrease of the apparent Km and a 2-fold increase of the apparent Vmax. of the reaction; however, both kinetic parameters increased with increasing phospholipid concentration. Tissue-factor apoprotein contributed to the reaction rate mainly by an increase of the Vmax., in both the presence (40,500-fold) and absence (4900-fold) of phospholipid. The formation of a ternary complex of Factor VIIa with tissue-factor apoprotein and phospholipid was responsible for a 15 million-fold increase in the catalytic efficiency of Factor X activation. The presence of Ca2+ was absolutely required for the stimulatory effects of phospholipid and apoprotein. The data fit a general model in which the Ca2(+)-dependent conformation allows Factor VIIa to bind tissue-factor apoprotein and/or a negatively charged phospholipid surface resulting into a decreased intrinsic Km and an increased Vmax. for the activation of fluid-phase Factor X.     

Production of 6-kestose by the filamentous fungus Gliocladium virens as affected by sucrose concentration

The filamentous fungus Gliocladium virens is able to produce fructooligosaccharides (FOS), fructose-containing sugars, used as functional ingredients to improve nutritional and technological properties of foods. In this work we evaluated FOS production by G. virens when grown in a wide range of sucrose concentrations (10–400 g l^?1). High sucrose concentrations increased both biomass and FOS production, including 6-kestose, a trisaccharide comprising β (2 → 6) linked fructosyl units, with enhanced stability and prebiotic activity when compared to the typical FOS β (2 → 1) linked. The highest 6-kestose yield (3 g l^?1) was achieved in media containing 150 g l^?1 sucrose after 4–5 days of culture, production being 90% greater than in media containing 10, 30, or 50 g l^?1 sucrose. After 5 days, FOS production declined markedly, following complete sucrose depletion in the medium. Although most of the β-fructofuranosidases preferentially catalyze sucrose hydrolysis, FOS production in G. virens grown in high sucrose concentration, might be attributed to a reverse hydrolysis by these enzymes. In conclusion, high sucrose concentrations increase growth of G. virens whilst 6-kestose accumulation in the medium seems to be controlled both by specific properties of β-fructofuranosidases and on the sucrose concentration.     

Identification of a pollen-specific gene,SlCRK1 (RFK2) in tomato

Plant receptor-like kinases (RLKs) are proteins that are involved in the regulation of development, hormone signaling, abiotic, and biotic stress responses. It has been suggested that cysteine-rich receptor-like kinases (CRKs), which are one of the largest RLK groups, is significant in pathogen defense and programmed cell death. The CRK1 gene is isolated and characterized from tomato (Solanum lycopersicum L.). The SlCRK1 has two C-X8-C-X2-C motifs: a trans-membrane region and a kinase domain similar to other CRKs. The semi-quantitative RT-PCR exhibits the specific expression of SlCRK1 in the flower, but not in the root, leaf, seed, and fruit of the tomato. In addition, SlCRK1 exhibits pollen-specific expression in the floral organ. SlCRK1 has pollen-specific cis-acting elements in the promoter region, and its promoter has pollen-specific activity in the homozygous transgenic plants of tomato and Arabidopsis as confirmed through histochemical GUS assays. Moreover, the expression of SlCRK1 is not detected via stress treatment or hormone treatment. In this study, SlCRK1 from tomato is characterized and its promoter can be useful in developing transgenic plants with foreign genes that should be expressed in pollens.     

2-O-substituted cyclodextrins as reversal agents for the neuromuscular blocker rocuronium bromide

A series of secondary face modified cyclodextrins (CDs) were synthesised with the aim of constructing host molecules capable of forming host-guest complexes with neuromuscular blockers, especially with rocuronium bromide. Perfacial 2-O-substitution of gamma-CD with 4-carboxybenzyl resulted in a CD host molecule 1 that forms a 1:1 binary complex with rocuronium bromide (K(a) 6.2 x 10(5) M(-1)). The biological activities of this compound and other derivatives as reversal agents of rocuronium bromide were examined in vitro (mouse hemi-diaphragm) and in vivo (anaesthetized guinea pigs). The host molecule 1 was found to exert potent reversal activity (ED(50) 0.21 micromol/kg, iv) against rocuronium-induced neuromuscular block, and thus proved the viability of using host molecules as antidotes of a biologically active compound.     

Fine needle biopsy with cytology in paediatrics: the importance of a multidisciplinary approach and the role of ancillary techniques

Fine needle biopsy (FNB) with cytology has long been regarded as an excellent technique as the first choice for diagnosing adult tumours. Being an inexpensive minimally invasive technique with high accuracy and diagnostic immediacy through rapid on‐site evaluation, it is also ideal for implementation in the paediatric setting, particularly in developing countries. Furthermore, it allows complementary and advanced procedures such as flow cytometry, polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH), among others, which enhances the diagnostic capacity of this technique and gives it a key role in risk stratification and therapeutic decision‐making for several tumours. The advantages of FNB are optimized in the setting of a multidisciplinary team where cytologist, clinician and radiologist play leading roles. Paediatric tumours are rare and most ancillary techniques are cost‐effective but complex to be implemented in small centres with limited experience in paediatric pathology. Therefore reference centres are essential, in order to establish teams with extensive experience and expertise. Hence, any child with a suspected malignancy should be directly referred to a paediatric oncology unit. Focusing on a practical approach to the assessment of paediatric lymphadenopathies and non‐central nervous system solid tumours we review the effectiveness of FNB as applied concurrently with ancillary techniques in a multidisciplinary approach to the diagnosis, prognosis and therapeutic decisions of paediatric tumours and tumour‐like lesions.     

Identification and grouping of Clostridium botulinum strains by numerical analysis of their electrophoretic protein patterns

Strains of Clostridium botulinum type A, type E and both non-proteolytic and proteolytic types B and F were characterized by their electrophoretic protein patterns. As the protein pattern changes during sporulation, special attention was paid to the prevention of sporulation by selecting an appropriate medium (Strasdine's medium plus 1% w/v glucose) and a scheme of repeated subculturing. Ribosomal proteins, evolutionarily conservative and hence relatively similar in all types of bacteria, were removed to optimize the resolving power of the electrophoretic technique. Protein patterns were compared by computing correlation coefficients of normalized densitometric tracings. The method is highly reproducible and its resolving power is high: all protein patterns found were specific. The strains tested fall into two main groups: the proteolytic and the non-proteolytic cluster. Type A strains form a separate subgroup within the proteolytic cluster, the same applies to type E strains within the non-proteolytic group. Although time-consuming for spore-forming bacteria, this method is, to our knowledge, the only technique that recognizes individual strains of Cl. botulinum. For non-spore-forming micro-organisms the method is certainly much simpler and hence even more valuable.     

Negative predictive value of SPECT for the occurrence of MACE in a medium-sized clinic in the Netherlands

Background

Single-photon emission computed tomography (SPECT) is an important prognostic tool in evaluating coronary artery disease (CAD), with a high negative predictive value (NPV) for the occurrence of major adverse cardiac events (MACE). The prognostic value of SPECT is disputed in women, patients with atrial fibrillation (AF), diabetes, left bundle branch block (LBBB) and renal impairment.

Methods

Seven hundred sixty-two patients without prior history of CAD who had SPECT without perfusion deficits were followed for 2 years for MACE. Predictive variables for the occurrence of MACE were reviewed by Cox proportional hazard regression, considering clinical information, resting-ECG data and SPECT data.

Results

The NPV of SPECT for the occurrence of MACE within 2 years was 95.8 %. Multivariate Cox regression revealed male gender as the only significant predictor for the occurrence of MACE, besides a positive stress ECG at SPECT and a low LVEF. AF, LBBB, renal impairment and diabetes had no significant effect on the prognosis after normal SPECT.

Conclusion

SPECT with normal perfusion images has great NPV in a medium-sized clinic in the Netherlands, even in patients with LBBB, AF, diabetes and renal impairment. MACE-free survival, however, was negatively influenced by male gender; we therefore propose more caution in men.     

A new strategy for inhibition of the spoilage yeasts Saccharomyces cerevisiae and Zygosaccharomyces bailii based on combination of a membrane-active peptide with an oligosaccharide that leads to an impaired glycosylphosphatidylinositol (GPI)-dependent yeast wall protein layer

Glycosylphosphatidylinositol (GPI)-dependent cell wall proteins in yeast are connected to the beta-1,3-glucan network via a beta-1,6-glucan moiety. Addition of gentiobiose or beta-1,6-glucan oligomers to growing cells affected the construction of a normal layer of GPI-dependent cell wall proteins at the outer rim of the Saccharomyces cerevisiae cell wall. Treated S. cerevisiae cells secreted significant amounts of cell wall protein 2, were much more sensitive to the lytic action of zymolyase 20T and displayed a marked increase in sensitivity to the small amphipathic antimicrobial peptide MB-21. Similar results in terms of sensitization of yeast cells to the antimicrobial peptide were obtained with the notorious food spoilage yeast Zygosaccharomyces bailii. Our results indicate that treating cells with a membrane-perturbing compound together with compounds that lead to an impaired construction of a normal GPI-dependent yeast wall protein layer represents an effective strategy to prevent the growth of major food spoilage yeasts.