Distinguishing Antimicrobial Models with Different Resistance Mechanisms via Population Pharmacodynamic Modeling

Semi-mechanistic pharmacokinetic-pharmacodynamic (PK-PD) modeling is increasingly used for antimicrobial drug development and optimization of dosage regimens, but systematic simulation-estimation studies to distinguish between competing PD models are lacking. This study compared the ability of static and dynamic in vitro infection models to distinguish between models with different resistance mechanisms and support accurate and precise parameter estimation. Monte Carlo simulations (MCS) were performed for models with one susceptible bacterial population without (M1) or with a resting stage (M2), a one population model with adaptive resistance (M5), models with pre-existing susceptible and resistant populations without (M3) or with (M4) inter-conversion, and a model with two pre-existing populations with adaptive resistance (M6). For each model, 200 datasets of the total bacterial population were simulated over 24h using static antibiotic concentrations (256-fold concentration range) or over 48h under dynamic conditions (dosing every 12h; elimination half-life: 1h). Twelve-hundred random datasets (each containing 20 curves for static or four curves for dynamic conditions) were generated by bootstrapping. Each dataset was estimated by all six models via population PD modeling to compare bias and precision. For M1 and M3, most parameter estimates were unbiased (<10%) and had good imprecision (<30%). However, parameters for adaptive resistance and inter-conversion for M2, M4, M5 and M6 had poor bias and large imprecision under static and dynamic conditions. For datasets that only contained viable counts of the total population, common statistical criteria and diagnostic plots did not support sound identification of the true resistance mechanism. Therefore, it seems advisable to quantify resistant bacteria and characterize their MICs and resistance mechanisms to support extended simulations and translate from in vitro experiments to animal infection models and ultimately patients.     

A simple method to separate base population and segregation effects in genomic relationship matrices

Background

Genomic selection and estimation of genomic breeding values (GBV) are widely used in cattle and plant breeding. Several studies have attempted to detect population subdivision by investigating the structure of the genomic relationship matrix G. However, the question of how these effects influence GBV estimation using genomic best linear unbiased prediction (GBLUP) has received little attention.

Methods

We propose a simple method to decompose G into two independent covariance matrices, one describing the covariance that results from systematic differences in allele frequencies between groups at the pedigree base (G_A^*) and the other describing genomic relationships (G_S) corrected for these differences. Using this decomposition and F_st statistics, we examined whether observed genetic distances between genotyped subgroups within populations resulted from the heterogeneous genetic structure present at the base of the pedigree and/or from breed divergence. Using this decomposition, we tested three models in a forward prediction validation scenario on six traits using Brown Swiss and dual-purpose Fleckvieh cattle data. Model 0 (M0) used both components and is equivalent to the model using the standard G-matrix. Model 1 (M1) used G_S only and model 2 (M2), an extension of M1, included a fixed genetic group effect. Moreover, we analyzed the matrix of contributions of each base group (Q) and estimated the effects and prediction errors of each base group using M0 and M1.

Results

The proposed decomposition of G helped to examine the relative importance of the effects of base groups and segregation in a given population. We found significant differences between the effects of base groups for each breed. In forward prediction, differences between models in terms of validation reliability of estimated direct genomic values were small but predictive power was consistently lowest for M1. The relative advantage of M0 or M2 in prediction depended on breed, trait and genetic composition of the validation group. Our approach presents a general analogy with the use of genetic groups in conventional animal models and provides proof that standard GBLUP using G yields solutions equivalent to M0, where base groups are considered as correlated random effects within the additive genetic variance assigned to the genetic base.     

Protective Effects of Hydroxysafflor Yellow A on β-Amyloid-Induced Neurotoxicity in PC12 Cells

The accumulation of extracellular amyloid-β peptide (Aβ) has been considered as one of the important causes of Alzheimer’s disease (AD), the most prevalent form of dementia. Hydroxysafflor yellow A (HSYA), a major active chemical component isolated from Carthamus tinctorius L., has been shown to possess neuroprotective actions in various ischemic models in vivo. The present study aimed to investigate the potential protective effect of HSYA against Aβ-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. The PC12 cells were pretreated with different concentrations (20, 40 and 80 μM) of HSYA for 2 h and then further treated with Aβ (20 μM) for 24 h. The results showed that Aβ could significantly decrease cell viability, glutathione level, mitochondrial membrane potential and the ratio of Bcl-2/Bax protein expression, while elevate the release of lactate dehydrogenase, the formation of DNA fragmentation, the levels of malondialdehyde and intracellular reactive oxygen species in PC12 cells. However, pretreatment with HSYA could effectively reverse these changes induced by Aβ in PC12 cells. Our experimental results demonstrate that HSYA may be a potential neuroprotective agent warranting further development for treatment of AD.     

Docking analyses on human muscarinic receptors: unveiling the subtypes peculiarities in agonists binding

The study presents a docking analysis for the interaction capabilities of some muscarinic receptors (i.e., M(1), M(2), and M(5)) whose full-length models were previously generated by us. In detail, the docking simulations involved a dataset of 30 agonists, taken from the literature, including a first series of oxathiolane/dioxolane congeners and a second subset of more heterogeneous ligands. The obtained results unveil that it is possible to discriminate among the binding modes of considered muscarinic receptors, developing specific interaction patterns which are significantly different for the arrangement of both polar and hydrophobic interactions. Thus, the M(1) subtype possesses the widest binding site, while the M(2) receptor is characterized by a large but asymmetric region that accommodates the ligand's ammonium head and finally the M(5) binding site is quite similar to that of M(2) subtype being univocally characterized by a second aspartate residue which interacts with the ammonium head. The significant correlations between docking scores and affinity values afford an encouraging validation for the reported binding modes and confirm the key role of molecular flexibility in the ligand recognition of muscarinic receptors.     

Responses of enzymatic antioxidants and non-enzymatic antioxidants in the cyanobacterium Microcystis aeruginosa to the allelochemical ethyl 2-methyl acetoacetate (EMA) isolated from reed (Phragmites communis)

Macrophytic allelochemicals are considered an environment-friendly and promising alternative to control algal bloom. However, studies examining the potential mechanisms of inhibitory allelochemicals on algae are few. The allelochemical ethyl 2-methyl acetoacetate (EMA), isolated from reed (Phragmites communis), was a strong allelopathic inhibitor on the growth of Microcystis aeruginosa. EMA-induced antioxidant responses were investigated in the cyanobacterium M. aeruginosa to understand the mechanism of EMA inhibition on algal growth. The activities of enzymatic antioxidants superoxide dismutase (SOD) and catalase (CAT), and the contents of non-enzymatic antioxidants reduced glutathione (GSH) and ascorbic acid (AsA) of M. aeruginosa cells were analyzed after treatments with different concentrations of EMA. Exposure of M. aeruginosa to EMA caused changes in enzyme activities and contents of non-enzymatic antioxidants in different manners. The decrease in SOD activity occurred first after 4h of EMA exposure, and more markedly after 40h. CAT activity did not change after 4h of EMA exposure, but increased obviously after 40h. The contents of AsA and GSH were increased greatly by EMA after 4h. After 60h, low EMA concentrations still increased the CAT activity and the contents of AsA and GSH, but high EMA concentrations started to impose a marked suppression on them. EMA increased dehydroascorbate (DHAsA) and oxidized glutathione (GSSG) contents during all exposure times. After 60h, the regeneration rates of AsA and GSH (represented by the AsA/DHAsA ratio and GSH/GSSG ratio, respectively) were reduced by high EMA concentrations. These results suggest that the activation of CAT and the availability of AsA and GSH at early exposure are important to counteract the oxidative stress induced by EMA, and the inactivation of SOD may be crucial to the growth inhibition of M. aeruginosa by EMA.     

Prion Protein Expression and Processing in Human Mononuclear Cells: The Impact of the Codon 129 Prion Gene Polymorphism

Background

So far, all clinical cases of new variant Creutzfeldt-Jakob disease (vCJD), thought to result from the Bovine Spongiform Encephalopathy (BSE) prion agent, have shown Methionine–Methionine (M/M) homozygosity at the M129V polymorphism of the PRNP gene. Although established, this relationship is still not understood. In both vCJD and experimental BSE models prion agents do reach the bloodstream, raising concerns regarding disease transmission through blood transfusion.

Methodology/Principal Findings

We investigated the impact of the M129V polymorphism on the expression and processing of the prion protein in human peripheral blood mononuclear cells (PBMCs) from three blood donor populations with Methionine-Methionine (M/M), Valine-Valine (V/V) and M/V genotypes. Using real-time PCR, ELISA and immunoblot assays we were unable to find differences in prion protein expression and processing relating to the M129V polymorphism.

Conclusions/Significance

These results suggest that in PBMCs, the M129V PrP polymorphism has no significant impact on PrP expression, processing and the apparent glycoform distribution. Prion propagation should be investigated further in other cell types or tissues.     

Who Takes Precautionary Action in the Face of the New H1N1 Influenza? Prediction of Who Collects a Free Hand Sanitizer Using a Health Behavior Model

Background

In order to fight the spread of the novel H1N1 influenza, health authorities worldwide called for a change in hygiene behavior. Within a longitudinal study, we examined who collected a free bottle of hand sanitizer towards the end of the first swine flu pandemic wave in December 2009.

Methods

629 participants took part in a longitudinal study assessing perceived likelihood and severity of an H1N1 infection, and H1N1 influenza related negative affect (i.e., feelings of threat, concern, and worry) at T1 (October 2009, week 43–44) and T2 (December 2009, week 51–52). Importantly, all participants received a voucher for a bottle of hand sanitizer at T2 which could be redeemed in a university office newly established for this occasion at T3 (ranging between 1–4 days after T2).

Results

Both a sequential longitudinal model (M2) as well as a change score model (M3) showed that greater perceived likelihood and severity at T1 (M2) or changes in perceived likelihood and severity between T1 and T2 (M3) did not directly drive protective behavior (T3), but showed a significant indirect impact on behavior through H1N1 influenza related negative affect. Specifically, increases in perceived likelihood (β = .12), severity (β = .24) and their interaction (β = .13) were associated with a more pronounced change in negative affect (M3). The more threatened, concerned and worried people felt (T2), the more likely they were to redeem the voucher at T3 (OR = 1.20).

Conclusions

Affective components need to be considered in health behavior models. Perceived likelihood and severity of an influenza infection represent necessary but not sufficient self-referential knowledge for paving the way for preventive behaviors.     

Modeling relationships between calving traits: a comparison between standard and recursive mixed models

Background

The use of structural equation models for the analysis of recursive and simultaneous relationships between phenotypes has become more popular recently. The aim of this paper is to illustrate how these models can be applied in animal breeding to achieve parameterizations of different levels of complexity and, more specifically, to model phenotypic recursion between three calving traits: gestation length (GL), calving difficulty (CD) and stillbirth (SB). All recursive models considered here postulate heterogeneous recursive relationships between GL and liabilities to CD and SB, and between liability to CD and liability to SB, depending on categories of GL phenotype.

Methods

Four models were compared in terms of goodness of fit and predictive ability: 1) standard mixed model (SMM), a model with unstructured (co)variance matrices; 2) recursive mixed model 1 (RMM1), assuming that residual correlations are due to the recursive relationships between phenotypes; 3) RMM2, assuming that correlations between residuals and contemporary groups are due to recursive relationships between phenotypes; and 4) RMM3, postulating that the correlations between genetic effects, contemporary groups and residuals are due to recursive relationships between phenotypes.

Results

For all the RMM considered, the estimates of the structural coefficients were similar. Results revealed a nonlinear relationship between GL and the liabilities both to CD and to SB, and a linear relationship between the liabilities to CD and SB.Differences in terms of goodness of fit and predictive ability of the models considered were negligible, suggesting that RMM3 is plausible.

Conclusions

The applications examined in this study suggest the plausibility of a nonlinear recursive effect from GL onto CD and SB. Also, the fact that the most restrictive model RMM3, which assumes that the only cause of correlation is phenotypic recursion, performs as well as the others indicates that the phenotypic recursion may be an important cause of the observed patterns of genetic and environmental correlations.     

Bioinformatics of granzymes: sequence comparison and structural studies on granzyme family by homology modeling

Cytotoxic lymphocytes (CTLs), the key players of cell mediated immunity, induce apoptosis by engaging death receptors or through exocytosis of cytolytic granules containing granzyme (proteases) and pore-forming protein (perforin). The crystal structure of granzyme B from human (B(h)) and rat (B(r)), as well as that of pro-granzyme K (K(h)) has been reported recently. In the present communication, we describe the homology modeling of granzyme family (in particular Gzm A(h), M(h), B(m), and C(m) from human and mouse) based on the crystal structural coordinates of trypsin, granzyme K (K(h)), and granzyme B (B(h)). These models have been used for establishing phylogenetic relationship as well as identifying characteristic features for designing specific inhibitors. The paper also highlights key residues at the S1, S2, and S2(') binding subsites in all granzyme, which may be involved in the structure-function relationship of this enzyme family. The predicted 3D homology models show a conserved two similar domain structure, i.e., an N-terminal domain and a C-terminal domain comprising predominantly of beta-sheet structure with a little alpha-helical content. Micro-heterogeneities have been observed in the vicinity of the active site in all granzymes as compared to granzyme B(h). For example, in granzyme M(h), valine is present at the S1 subsite instead of arginine. Similarly differences at S2 (Leu-->Phe), S3 (Ser-->Gly), and S4 (Arg-->Asn) subsites are quite apparent and appear to hold the potential for selective designing of inhibitors for possible therapeutic applications. Furthermore, analysis of the electrostatic surface potential on the shape of granzyme-inhibitor binding groove reveals clear differences at the reactive site. Additionally the different posttranslational modification sites such as phosphorylation (e.g., in granzyme M Thr101, Ser109), myristoylation (Gly22, 117, and 131), and glycosylation (Ser160) have been identified, as very little is known about the functional significance of these modifications in the granzyme family. Thus, glycosylation at Ser160 in granzyme M may influence the net charge of the enzyme, resulting in altered substrate binding as compared to granzyme B. Also this modification may influence the rate of complexation and binding affinity with proteoglycans. These studies are expected to contribute towards the basic understanding of functional associations of the granzymes with other molecules and their possible role in apoptosis.     

NIH disease funding levels and burden of disease

Background

An analysis of NIH funding in 1996 found that the strongest predictor of funding, disability-adjusted life-years (DALYs), explained only 39% of the variance in funding. In 1998, Congress requested that the Institute of Medicine (IOM) evaluate priority-setting criteria for NIH funding; the IOM recommended greater consideration of disease burden. We examined whether the association between current burden and funding has changed since that time.

Methods

We analyzed public data on 2006 NIH funding for 29 common conditions. Measures of US disease burden in 2004 were obtained from the World Health Organization''s Global Burden of Disease study and national databases. We assessed the relationship between disease burden and NIH funding dollars in univariate and multivariable log-linear models that evaluated all measures of disease burden. Sensitivity analyses examined associations with future US burden, current and future measures of world disease burden, and a newly standardized NIH accounting method.

Results

In univariate and multivariable analyses, disease-specific NIH funding levels increased with burden of disease measured in DALYs (p = 0.001), which accounted for 33% of funding level variation. No other factor predicted funding in multivariable models. Conditions receiving the most funding greater than expected based on disease burden were AIDS ($2474 M), diabetes mellitus ($390 M), and perinatal conditions ($297 M). Depression ($719 M), injuries ($691 M), and chronic obstructive pulmonary disease ($613 M) were the most underfunded. Results were similar using estimates of future US burden, current and future world disease burden, and alternate NIH accounting methods.

Conclusions

Current levels of NIH disease-specific research funding correlate modestly with US disease burden, and correlation has not improved in the last decade.     

Time-course correlation of early toxic events in three models of striatal damage: Modulation by proteases inhibition

Metabolic alterations in the nervous system can be produced at early stages of toxicity and are linked with oxidative stress, energy depletion and death signaling. Proteases activation is responsible for triggering deadly cascades during cell damage in toxic models. In this study we evaluated the early time-course of toxic events (oxidative damage to lipids, mitochondrial dysfunction and LDH leakage, all at 1, 3 and 6 h) in rat striatal slices exposed to quinolinic acid (QUIN, 100 μM) as an excitotoxic/pro-oxidant model, 3-nitropropionic acid (3-NP, 1 mM) as an inhibitor of mitochondrial succinate dehydrogenase, and a combined model produced by the co-administration of these two toxins at subtoxic concentrations (21 and 166 μM for QUIN and 3-NP, respectively). In order to further characterize a possible causality of caspases or calpains on the toxic mechanisms produced in these models, the broad calpain inhibitor IC1 (50 μM), and the pan-caspase inhibitor Z-VAD (100 μM) were tested. Lipid peroxidation (LP) was increased at all times and in all models evaluated. Both IC1 and Z-VAD exerted significant protection against LP in all models and at all times evaluated. Mitochondrial dysfunction (MD) was consistently affected by all toxic models at 3 and 6 h, but was mostly affected by 3-NP and QUIN at 1 h. IC1 differentially protected the slices against 3-NP and QUIN at 1 h and against QUIN at 3 h, while Z-VAD exhibited positive actions against QUIN and 3-NP at all times tested, and against their combination at 3 and 6 h. LDH leakage was enhanced at 1 and 3 h in all toxic models, but this effect was evident only for 3-NP + QUIN and 3-NP at 6 h. IC1 protected against LDH leakage at 1 h in 3-NP + QUIN and 3-NP models, at 3 h in all toxic models, and at 6 h in 3-NP + QUIN and 3-NP models. In turn, Z-VAD protected at 1 and 6 h in all models tested, and at 3 h in the combined and QUIN models. Our results suggest differential chronologic and mechanistic patterns, depending on the toxic insult. Although LP, MD and membrane cell rupture are shared by the three models, the occurrence of each event seems to obey to a selective recruitment of damaging signals, including a differential activation of proteases in time. Proteases activation is likely to be an up-stream event influencing oxidative stress and mitochondrial dysfunction in these toxic models.     

The effectiveness of S9 and microsomal mix on activation of cyclophosphamide to induce genotoxicity in human lymphocytes

Comparative results are presented on the effectiveness of rat-liver S9 or microsomal mix (M mix) in activating cyclophosphamide (CP) and its ability to induce a clastogenic effect in human lymphocytes in vitro. Structural chromosome changes were analysed exclusively in 1st division (M1) metaphases post-exposure. A high genotoxic response was observed for both metabolizing systems used. With an exposure of 2 h to different concentrations of S9 or M mix, the highest aberration yields were always found for the highest protein content. For CP treatment times of 1, 2 or 4 h together with S9 mix (protein content 10 mg/ml) or M mix (4 mg/ml), the latter was more efficient. With both systems, a lower clastogenic effect of CP was found at 4 h exposure than at 1 h or 2 h. Only a weak cytotoxic effect, reflected mainly by the reduction in the percentage of 3rd cycle cells (M3), and measured in terms of the proportion of M1, M2 and M3 cells, was induced by both systems.     

Quantitative structure-selectivity relationship for M2 selectivity between M1 and M2 of piperidinyl piperidine derivatives as muscarinic antagonists

Muscarinic M2 receptor antagonists with high subtype selectivity (M2/M1) will decrease the toxicity in central nervous system in treatment of AD. The exploration of quantitative structure-selectivity relationship (QSSR) to muscarinic M2 receptor antagonists will provide design information for drug with fewer side effects. In this paper, CoMFA models of pK(i)(M1), pK(i)(M2) and p[K(i)(M2)/K(i)(M1)] (pK(i)(M2)-pK(i)(M1)) were used to study the subtype selectivity (M2/M1) of piperidinyl piperidine derivatives as muscarinic M2 subtype receptor antagonists. The parameters of the three models are: 0.633, 0.636 and 0.726 for cross-validated r(2) (r(cv)(2)), 0.109, 0.204 and 0.09 for the Standard error of estimate (SD), respectively. The results show the model of p[K(i)(M2)/K(i)(M1)] is the best one for design of piperidinyl piperidine derivatives as muscarinic antagonists with high subtype selectivity (M2/M1).     

Forms of Selenium Affect its Transport, Uptake and Glutathione Peroxidase Activity in the Caco-2 Cell Model

The aim of this study was to investigate the possible time- and dose-dependent cytotoxic effects of cobalt chloride on Vero cells. The cultured cells were incubated with different concentrations of cobalt chloride ranging from 0.5 to 1,000 μM, and cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and resazurin assays. Possible protective effects of vitamin E, coenzyme Q(10), and zinc chloride were also tested in this system. A gradual decrease in cell proliferation was observed at concentrations ~≥ 200 μM in incubation periods of 24, 48, 72, and 96 h with MTT assay. Exposure of cells to 500 and 1,000 μM cobalt chloride caused significant decrease in cell survival. A biphasic survival profile of cells was observed at 1-25 μM concentration range following 96 h of incubation. With resazurin assay, cytotoxicity profile of CoCl(2) was found comparable to the results of MTT assay, particularly at high concentrations and long incubation periods. Dose-dependent cytotoxicity was noted following exposure of cells to ≥ 250 μM of CoCl(2) for 24 h and ≥ 100 μM concentrations of CoCl(2) for 48-96 h. Pretreatment of cells with ZnCl(2) for 4 or 24 h provided significant protection against cobalt chloride-induced cytotoxicity when measured with MTT assay. However, vitamin E or coenzyme Q(10) was not protective. CoCl(2) had dose- and time-dependent cytotoxic effects in Vero cells. Preventive effect of ZnCl(2) against CoCl(2)-induced cytotoxicity should be considered in detail to define exact mechanism of toxicity in Vero cells.     

Envejecer sin ver: evaluación del ajuste a la pérdida visual sobrevenida en la vejez

Introduction

The adjustment process to visual impairment can be approached by using theoretical models. The key variables in these models are usually measured by using psychometric instruments. The measurements can be taken from those already existing for the general population or be specifically designed for the visually impaired population. If the chosen measurements are reasonably valid and behave as the model predicts, they can be further used for designing programs that improve the process of adjusting.We describe the identification, adaptation and validation of some theses measurements.

Method

We selected the psychometrics instruments to be used in the research: the Age-Related Vision Loss Scale (AVL) by Horowitz and Reinhardt; the Nottingham Adjustment Scale (NAS) by Dodds, and the Geriatric Depression Scale (GDS) by Brink and Yesavage. The AVL and NAS were adapted for use in Spain. The referred measurements were applied to a sample of 335 respondents together with the Scale of Subjective Wellbeing (EBS), and their psychometric properties were assessed.

Results

The estimated reliabilities were: AVL (0.80), NASA2 (0.87), NASB (0.81), NASC (0.75), NASE (0.87), GDS (0.90). The relationships between the measurements were all in the expected direction, and the magnitude of the convergent-validity coefficients was considered as acceptable.

Conclusions

Our results suggests that the available measurements discussed above are appropriate for assessing the adjustment process, and are useful tools for individual assessment, as well as for designing intervention programs.All the measurements are available in computerized form in www.proyectotarragona.es.     

Probiotic Bacillus amyloliquefaciens mediate M1 macrophage polarization in mouse bone marrow-derived macrophages

Depending on the microenvironment, macrophages can acquire distinct functional phenotypes, referred to as classically activated M1 and M2. M1 macrophages are considered potent effector cells that kill intracellular pathogens, and M2 macrophages promote the resolution of wound healing. In this study, we are interested to know whether probiotic Bacillus amyloliquefaciens (Ba) can induce macrophages polarization. Real-time fluorescence PCR analysis demonstrated that the expression of IL-1β, iNOS, TNF-α and IL-6 genes for M1 macrophages was significantly increased at 1.5 h after probiotic Ba treatment compared to the probiotic Ba-free treatment (P < 0.01), whereas the expression of M2 macrophage marker genes (Arg1, Fizz1, MR, Ym1) was decreased (P < 0.05). Furthermore, the phagocytic activity was dramatically increased in the Ba-treated BMDMs using a FITC-dextran endocytosis assay. Together, these findings indicated that probiotic Ba facilitated polarization of M1 macrophages and enhanced its phagocytic capacity. The results expanded our knowledge about probiotic function-involved macrophage polarization.     

Temporal variations in the erythrocyte permeability to bupivacaine, etidocaine and mepivacaine in mice

Temporal changes in membrane permeability to bupivacaine (B), etidocaine (E) and mepivacaine (M) documented by their erythrocytic penetration were studied in mice. Temporal variations of B, E and M erythrocytic penetration were demonstrated with a maximum at 04.00 h for B (amplitude = 148%), 10.00 h for E (amplitude = 146%) and at 10.00 h for M (amplitude = 75%). Differences in the circadian pattern of erythrocytic penetration of B, E and M are discussed according to physicochemical properties of these three agents.     

Individual Organ Failure and Concomitant Risk of Mortality Differs According to the Type of Admission to ICU – A Retrospective Study of SOFA Score of 23,795 Patients

Introduction

Organ dysfunction or failure after the first days of ICU treatment and subsequent mortality with respect to the type of intensive care unit (ICU) admission is poorly elucidated. Therefore we analyzed the association of ICU mortality and admission for medical (M), scheduled surgery (ScS) or unscheduled surgery (US) patients mirrored by the occurrence of organ dysfunction/failure (OD/OF) after the first 72h of ICU stay.

Methods

For this retrospective cohort study (23,795 patients; DIVI registry; German Interdisciplinary Association for Intensive Care Medicine (DIVI)) organ dysfunction or failure were derived from the Sequential Organ Failure Assessment (SOFA) score (excluding the Glasgow Coma Scale). SOFA scores were collected on admission to ICU and 72h later. For patients with a length of stay of at least five days, a multivariate analysis was performed for individual OD/OF on day three.

Results

M patients had the lowest prevalence of cardiovascular failure (M 31%; ScS 35%; US 38%), and the highest prevalence of respiratory (M 24%; ScS 13%; US 17%) and renal failure (M 10%; ScS 6%; US 7%). Risk of death was highest for M- and ScS-patients in those with respiratory failure (OR; M 2.4; ScS 2.4; US 1.4) and for surgical patients with renal failure (OR; M 1.7; ScS 2.7; US 2.4).

Conclusion

The dynamic evolution of OD/OF within 72h after ICU admission and mortality differed between patients depending on their types of admission. This has to be considered to exclude a systematic bias during multi-center trials.     

Bioinformatic analysis of the neprilysin (M13) family of peptidases reveals complex evolutionary and functional relationships

Background  

The neprilysin (M13) family of endopeptidases are zinc-metalloenzymes, the majority of which are type II integral membrane proteins. The best characterised of this family is neprilysin, which has important roles in inactivating signalling peptides involved in modulating neuronal activity, blood pressure and the immune system. Other family members include the endothelin converting enzymes (ECE-1 and ECE-2), which are responsible for the final step in the synthesis of potent vasoconstrictor endothelins. The ECEs, as well as neprilysin, are considered valuable therapeutic targets for treating cardiovascular disease. Other members of the M13 family have not been functionally characterised, but are also likely to have biological roles regulating peptide signalling. The recent sequencing of animal genomes has greatly increased the number of M13 family members in protein databases, information which can be used to reveal evolutionary relationships and to gain insight into conserved biological roles.