A machine learning-based model for 1-year mortality prediction in patients admitted to an Intensive Care Unit with a diagnosis of sepsis.

INTRODUCTION: Sepsis is associated to a high mortality rate, and its severity must be evaluated quickly. The severity of illness scores used are intended to be applicable to all patient populations, and generally evaluate in-hospital mortality. However, patients with sepsis continue to be at risk of death after hospital discharge. OBJECTIVE: To develop a model for predicting 1-year mortality in critical patients diagnosed with sepsis. PATIENTS: The data corresponding to 5650 admissions of patients with sepsis from the Medical Information Mart for Intensive Care (MIMIC-III) database were evaluated, randomly divided as follows: 70% for training and 30% for validation. DESIGN: A retrospective register-based cohort study was carried out. The clinical information of the first 24h after admission was used to develop a 1-year mortality prediction model based on Stochastic Gradient Boosting (SGB) methodology. Variable selection was addressed using Least Absolute Shrinkage and Selection Operator (LASSO) and SGB variable importance methodologies. The predictive power was evaluated using the area under the ROC curve (AUROC). RESULTS: An AUROC of 0.8039 (95% confidence interval (CI): [0.8033 0.8045]) was obtained in the validation subset. The model exceeded the predictive performances obtained with traditional severity of disease scores in the same subset. CONCLUSION: The use of assembly algorithms, such as SGB, for the generation of a customized model for sepsis yields more accurate 1-year mortality prediction than the traditional scoring systems such as SAPS II, SOFA or OASIS.

GROUT-CONCRETE INTERFACE BOND PERFORMANCE: EFFECT OF INTERFACE MOISTURE ON THE TENSILE BOND STRENGTH AND GROUT MICROSTRUCTURE.

Bond between two cementitious materials is crucial in applications such as repairs, overlays, and connections of prefabricated bridge elements (PBEs), to name just a few. It is the latter that has special interest to the authors of this paper. After performing a dimensional stability study on grout-like materials commonly used as connections between PBEs, it was observed that the so-called 'non-shrink' cementitious grouts showed a considerable amount of early-age shrinkage. This might have negative effects on the integrity of the structure, due not only to the grout material's early degradation, but also to a possible loss of bond between the grout and the prefabricated concrete element. Many factors affect the bond strength between two cementitious materials (e.g., grout-concrete), the presence of moisture at the existing concrete substrate surface being one of them. In this regard, pre-moistening the concrete substrate surface prior to the application of the grout material is sometimes recommended for bond enhancement. This topic has been the focus of numerous research studies in the past; however, there is still controversy among practitioners on the real benefits that this practice might provide. This paper evaluates the tensile bond performance of two non-shrink cementitious grouts applied to the exposed aggregate surface of a concrete substrate, and how the supply of moisture at the grout-concrete interface affects the bond strength. "Pull-off" bond results show increased tensile bond strength when the concrete surface is pre-moistened. Reasons to explain the observed increased bond strength are given after a careful microstructural analysis of the grout-concrete interface. Interfaces where sufficient moisture is provided to the concrete substrate such that moisture movement from the grout is prevented show reduced porosity and increased hydration on the grout side of the interface, which is thought to directly contribute to the increased tensile bond strength.

Assessment of the bio-preparedness and of the training of the French hospital laboratories in the event of biological threat.

A national laboratory network 'Biotox-Piratox' was created in 2003 in France with the purpose of detecting, confirming and reporting potential biological and chemical threat agents. This network is divided into three levels: Level 1 is dedicated to the evaluation of risks (biological, chemical, radiological), to sampling and packing. Level 2 consists of university and military hospitals, who deal with biological specimens, and of environmental and veterinary laboratories, who deal with environmental and animal samples. Level 3 comprises national reference laboratories and the Jean Mérieux biosafety level (BSL)-4 laboratory in Lyon. This report presents the results of four bio-preparedness exercises to check critical points in the processing of samples. These exercises took place in 2007, 2009, 2010 and 2011. Each of them consisted of two parts. The first part was the identification of an unknown bacterial strain and its susceptibility to antibiotics used as a default in case of a bioterrorist event. The second part was the detection of Class III microorganisms, mainly by molecular techniques. The main lesson learnt in these exercises was that the key to successful detection of biological agents in case of a biological threat was standardisation and validation of the methods implemented by all the laboratories belonging to the network.

[Gastrocolocutaneous fistula: an uncommon complication of percutaneous endoscopic gastrostomy]. / Fístula gastrocolocutánea: una infrecuente complicación de la gastrostomía endoscópica percutánea.

Endoscopic percutaneous gastrostomy is a safe technique although with potential complications before which the clinician has to be on alert in order to early detect them even after a long period of normal functioning. Most of them represent minor problems. Gastrocolocutaneous fistula is a rare but severe complication favored by some risk factors such as previous post-surgical adherences, deformities of the spine, or excessive gastric inflation at the time of performing the technique. We present the case of a patient with PEG with this complication that occurred after the first tube replacement. Our goal was in two senses: on the one hand, to analyze the preventive aspects and basic guidelines for a safe PEG placement to minimize the risks; on the other hand, to alert on the possible presence of this entity to prevent a progressive nutritional impairment. This complication ought to be included in the differential diagnosis of the diarrhea syndrome in the patient carrying a PEG. The diagnostic techniques of choice are radiologic tests such as CT scan and contrast media administration through the tube. Surgical therapy should be reserved to patients with acute peritonitis in order to perform a new gastrostomy.

An adaptation of Pfam profiles to predict protein sub-cellular localization in Gram positive bacteria.

Predicting the sub-cellular localization of a protein can provide useful information to uncover its molecular functions. In this sense, numerous prediction techniques have been developed, which usually have been focused on global information of the protein or sequence alignments. However, several studies have shown that the functional nature of proteins is ruled by conserved sub-sequence patterns known as domains. In this paper, an alternative methodology (PfamFeat) for gram-positive bacterial sub-cellular localization was developed. PfamFeat is based on information provided by Pfam database, which stores a series of HMM-profiles describing common protein domains. The likelihood of a sequence, to be generated by a given HMM-profile, can be used to characterize sequences in order to use pattern recognition techniques. Success rates obtained with a simple one-nearest neighbor classifier demonstrate that this method is competitive with popular sub-cellular prediction algorithms and it constitutes a promising research trend.

Differential PbP27 expression in the yeast and mycelial forms of the Paracoccidioides brasiliensis species complex.

p27 is an antigenic protein produced by Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis (PCM). Despite its unknown function, it has been suggested as a putative virulence factor, proposed as a suitable target for the design of diagnostic tools and vaccines, and considered as an enhancer in antifungal treatment of PCM. We evaluated sequence polymorphisms of PbP27 gene sequence among isolates, finding some polymorphisms associated with the isolates' phylogenetic origin. In order to determine if there was a differential expression pattern between morphological states and among isolates, we also evaluated PbP27 expression, at transcriptional and translational levels, in mycelia and yeast cultures in 14 isolates belonging to the P. brasiliensis species complex (S1, PS2, PS3, and "Pb01-like", proposed to be named Paracoccidioides lutzii) by two techniques, real time RT-PCR (RT-qPCR) and protein dot blot. For the latter, four protein extracts from different cell localizations (SDS or ß-mercaptoethanol, cytoplasmic and extracellular proteins) were analyzed for each isolate. p27 was present in the four extracts evaluated, mainly in the SDS extract, corresponding to an extract containing proteins loosely attached to the cell wall. This information correlates with immunohistochemical analysis, where positive staining of the yeasts' cell wall was observed. We found that p27 was present in all isolates, mainly in the yeast form. This pattern was corroborated by RT-qPCR results, with higher expression levels found in the yeast form for most of the isolates. The results provide new insights into the expression patterns of this protein, and further characterize it in view of potential uses as a diagnostic and/or therapeutic tool.

Estimators and confidence intervals for the proportion using binary auxiliary information with applications to pharmaceutical studies.

Estimation of a proportion is commonly used in areas such as medicine, biopharmaceutical experiments, etc. Estimation of a proportion using auxiliary information has not been investigated in the literature. Ratio estimators of the population proportion and two-sided confidence intervals based upon auxiliary information are derived in this paper. Real data extracted from the Spanish National Health Survey are used to demonstrate the application of the proposed methods in the estimation of prevalences. Results derived from simulation studies show that proposed estimators are more efficient than the traditional estimator. Proposed confidence intervals outperform the alternative methods, especially in terms of interval width. A study on patients with hypertension is also considered to calculate various estimators and confidence intervals.

[Spanish version of the CAM-ICU (Confusion Assessment Method for the Intensive Care Unit). Pilot study of validation]. / Versión en español del método para la evaluación de la confusión en cuidados intensivos, estudio piloto de validación.

OBJECTIVE: To validate the Spanish version of the CAM-ICU. DESIGN: Validation study. The inter-rater reliability and validity were evaluated using a blind comparison with the DSM-IVTR criteria (reference standard) in a group of patients hospitalized in an Intensive Care Unit (ICU). SETTING: Medical-surgical ICU. PATIENTS: 129 adults with RASS >-4 score, within the 24-48 h of ICU admission. Independent application of the CAM-ICU by two intensive care specialists and evaluation by a psychiatrist using the DSM-IVTR criteria for delirium. RESULTS: Prevalence of delirium in the sample was 26.4%, this being and 48.3% in the 29 patients who received mechanical ventilation. Inter-rater reliability in the whole sample according to the Kappa index was 0.792 (95% CI 0.662-0.922, p<0.001) and in those who received mechanical ventilation was 0.726 (95% CI 0.487-0.965, p<0.001). The sensitivity, specificity, positive predicted value (PPV), negative predicted value (NPV), positive likelihood ratio (+LR), and negative likelihood ratio (-LR) were 79.4% (95% CI 63.2-89.7%); 97.9% (95% CI 92.6-99.4%); 93.1% (95% CI 78.0-98.1%); 93.0% (95% CI 86.3-96.6%); 37.72 (95% CI 9.47-150.20) and 0.21(95% CI 0.11-0.41), respectively, in the whole sample. In mechanically-ventilated patients, sensitivity, specificity, PPV, NPV, +LR and -LR were 92.9% (95% CI 68.5-98.7%); 86.7% (95% CI 62.1-96.3%); 86.7% (95% CI 62.1-96.3%); 92.9% (95% CI 68.5-98.7%); 6.96(95% CI 1.90-25.51) and 0.08 (95% CI 0.01-0.55), respectively. CONCLUSION: The Spanish version of the CAM-ICU is reliable. Its sensitivity, specificity and predictive values should be considered good.

Evaluation of six pesticides leaching indexes using field data of herbicide application in Casablanca Valley, Chile.

A field study was performed to evaluate the accuracy of six pesticide screening leaching indexes for herbicide movement. Adsorption, dissipation and soil movement were studied in a vineyard in a sandy loam soil during 2005 season. Simazine, diuron, pendimethalin, oxyfluorfen and flumioxazin were applied to bare soil at rates commonly used, and their soil concentrations throughout soil profile were determined at 0, 10, 20, 40 and 90 days after application (DAA). Herbicides were subjected to two pluviometric regimens, natural field condition and modified conditions (plus natural rainfall 180 mm). Leaching indexes utilized were: Briggs's Rf, Hamaker's Rf, LEACH, LPI, GUS and LIX. Simazine reached 120 cm, diuron 90 cm, flumioxazin 30 cm soil depth respectively. Pendimethalin and oxyfluorfen were retained up to 5 cm. None of the herbicides leaching was affected by rainfall regimen. Only flumioxazin field dissipation was clearly affected by pluviometric condition. The best representation of the herbicide soil depth movement and leaching below 15 cm soil depth were: Hamaker's Rf < Briggs's Rf < GUS < LPI, < LEACH < LIX. Field results showed a good correlation between herbicides K(d) and their soil depth movement and mass leached below 15 cm soil depth.

[Comparative study of three systems for in vitro activity investigation of fluconazole against yeast isolates of clinical interest]. / Estudio comparativo de tres sistemas para la investigación in vitro de la actividad del fluconazol frente a organismos levaduriformes de interés clínico.

BACKGROUND: Study of antifungal sensitivity can help in treatment screening and evaluation of patients suffering from some fungal infections. The purpose of this study is to compare fluconazole MICs obtained by E-test and agar dilution with the NCCLS method. MATERIAL AND METHODS: The in vitro activity of fluconazole against 158 yeast strains by three systems: E-test, agar dilution and the microbroth NCCLS M27P method. RESULTS AND CONCLUSION: A correlation between 84 to 100% was observed the degree varying in the result among different species. The E-test was found to be comparable to the NCCLS M27P microbroth method, was easier to perform and provides MIC result for Candida species within 24 h.

Effect of human immunodeficiency virus type 1 on intracellular activation and superoxide production by neutrophils.

The immunopathogenesis of AIDS is associated with the development of opportunistic infections by intracellular pathogens that can invade and reproduce freely because of impaired cellular functions. Neutrophils from asymptomatic human immunodeficiency virus (HIV) type 1-infected persons and from symptomatic patients with AIDS were found to retain normal phagocytosis activity while producing significantly less superoxide than neutrophils from HIV-1-negative subjects, when stimulated through Fc receptors or protein kinase C. After priming with a synthetic HIV-1 envelope peptide and stimulation via the Fc receptor, the neutrophils from HIV-1-negative controls had suppressed superoxide production, reduced phosphorylation of two unidentified cellular proteins, and increased expression of a third phosphoprotein. These results suggest that HIV-1 can produce direct functional damage of neutrophils through binding of envelope components to the cell membrane.

Study of the susceptibility of yeast isolates of clinical interest to five antifungal agents using the E test.

The E test is a quantitative technique for determining antimicrobial susceptibility; it is based on the diffusion of a stable predetermined gradient of a specific antifungal agent along an inert plastic strip which is applied to a solid culture medium. The E test is an alternative method for determining inhibitory concentrations of antimicrobial agents. The aim of the present study was to determine the in vitro susceptibility of different yeasts to 5 antifungal agents using the E test. The antifungal susceptibility of 87 strains, 73 of which were yeasts obtained from clinical samples, 11 were Prototheca strains and 3 controls, were examined using a gradient diffusion technique (E test). Of these isolates, 13% of Candida albicans were resistant to flucytosine, and 20%, 17% and 33% showed resistance to ketoconazole, itraconazole and fluconazole, respectively. All Candida krusei isolates showed resistance to flucytosine and fluconazole. The Candida parapsilosis and Candida tropicalis strains all presented in vitro susceptibility to all the agents tested. Prototheca strains were only susceptible in vitro to amphotericin B. It was found that the E test was easy to perform, and provided MIC values similar to those obtained with other well documented techniques. It was therefore concluded that the E test could be implemented as a standard procedure in clinical mycology laboratories.

[Intraoperative anesthetic management of kidney failure in adult liver transplantation. Conventional hemodialysis]. / Manejo anestésico intraoperatorio del fallo renal en el trasplante hepático del adulto. Hemodiálisis convencional.

OBJECTIVE: To evaluate our application of indications, use and benefits of conventional hemodialysis during surgery in patients with advanced liver disease and acute or chronic renal failure undergoing liver transplantation (LP), liver retransplantation (LRT) or combined hepatorenal transplantation (CHRT). PATIENTS AND METHODS: We retrospectively reviewed the cases of 22 patients with advanced liver disease, 11 with acute renal failure and 11 with chronic renal failure. We performed 6 LT, 5 LRT and 11 CHRT. The following data were recorded in the periods before, during and immediately after surgery: metabolic, hemodynamic and coagulation parameters; bicarbonate, calcium and inotropic drug requirements; incidences during reperfusion of the graft; surgical technique used; and survival. RESULTS: Seven patients (32%) needed hemodialysis, 4 (18%) needed ultrafiltration, 7 (32%) needed both and 4 (18%) required neither. For 6 patients total clamping of the inferior vena cava (ICV) was required with external venovenous bypass. For 8 patients total clamping of the IVC was performed without venovenous bypass. For 8 others IVC clamping was partial with retrohepatic preservation (piggy-back). There were 2 deaths during surgery, 4 more within the first month after surgery and 4 more in the second month. Overall survival was 36.4% among acute patients and 72.7% among CHRT patients. CONCLUSIONS: 1) Conventional hemodialysis during surgery is feasible and gives good results; 2) conventional "high efficiency" hemodialysis is more effective and useful in these patients than is either slow, continuous hemodialysis or filtration; 3) the survival rate of CHRT patients is similar to that of patients undergoing LT with normal kidney function, and 4) partial IVC clamping in the anhepatic phase may decrease the need for ultrafiltration.

Entamoeba histolytica: fecal antigen capture immunoassay for the diagnosis of enteric amebiasis by a monoclonal antibody.

Amebiasis continues to be of epidemiological importance in underdeveloped countries. Clinical diagnosis and epidemiological setting in a region are based on the fecal microscopic identification of cysts or trophozoites. This procedure requires well trained personnel, is laborious, of low sensitivity and frequently yields false-positives results. The present study was designed to develop an immunoenzymatic fecal 96 kDa antigen capture test (COPROELISA-Eh) more sensitive and specific than microscopic diagnosis of amebiasis. Triplicates of 177 stool samples processed by the formol-ether concentration method, were defined as positive or negative by three experienced microscopic observers. Another aliquot was submitted to the antigen capture test by a monoclonal antibody against a specific membrane antigen of pathogenic strains of Entamoeba histolytica. Optical densities were interpreted as positive when they exceeded the mean value of negative samples plus two standard deviations. COPROELISA-Eh showed a 94.4% sensitivity, 98.3% specificity, 96.2% positive predictive value and 97.6% negative predictive value for the detection of E. histolytica in feces. COPROELISA-Eh is more sensitive and specific than microscopic examination, does not require specially trained personnel and allows the simultaneous processing of a large number of samples.

Activation of human monocyte-derived macrophages by immune complexes containing low-density lipoprotein.

Human monocyte-derived macrophages are transformed into foam cells upon incubation with immune complexes containing low-density lipoprotein (LDL-IC), which are internalized predominantly through Fc gamma receptor-mediated phagocytosis. We investigated whether the FcR gamma-mediated ingestion of LDL-IC is associated with functional and metabolic activation of the ingesting cells. As end points we used the assay of released interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha) and the reduction of nitroblue tetrazolium, which measures the respiratory burst. LDL-IC, added to the macrophages in concentrations known to induce intracellular accumulation of cholesterol esters and foam cell transformation, stimulated both the cytokine release and the respiratory burst more efficiently than control immune complexes. Time course studies of cytokine release and mRNA expression suggest that the synthesis and release of these two cytokines is under independent control. TNF alpha was released almost immediately after addition of LDL-IC to the macrophages, coinciding with increased early expression of TNF alpha mRNA, detectable 30 min after stimulation. In contrast, IL-1 beta was only increased in stimulated cell supernatants after 8 hr, and the onset of expression of IL-1 beta mRNA was also delayed in comparison to that of TNF alpha mRNA. We noted wide variations in the amounts of TNF alpha released by monocyte-derived macrophages from different donors. We also found that those macrophages which released higher levels of TNF alpha also took up higher amounts of 125I-labeled LDL, suggesting that the expression of LDL receptors by LDL-IC-stimulated macrophages is somehow linked to the degree of activation of these cells. Experiments using the measurement of the oxidative burst as end point corroborated that LDL-IC cause a general activation of macrophage functions. In conclusion, human macrophages are efficiently activated by LDL-IC, as reflected by the release of IL-1 beta and TNF alpha and by the release of oxygen active radicals. Thus, the presentation of LDL-IC to human macrophages induces a variety of metabolic and functional changes which are likely to contribute, directly or indirectly, to endothelial damage and progression of the atheromatous lesion.