Kidney function changes in acute heart failure: a practical approach to interpretation and management.

Worsening kidney function (WKF) is common in patients with acute heart failure (AHF) syndromes. Although WKF has traditionally been associated with worse outcomes on a population level, serum creatinine concentrations vary greatly during episodes of worsening heart failure, with substantial individual heterogeneity in terms of their clinical meaning. Consequently, interpreting such changes within the appropriate clinical context is essential to unravel the pathophysiology of kidney function changes and appropriately interpret their clinical meaning. This article aims to provide a critical overview of WKF in AHF, aiming to provide physicians with some tips and tricks to appropriately interpret kidney function changes in the context of AHF.

Enantioselective Catalysis with Pyrrolidinyl Gold(I) Complexes: DFT and NEST Analysis of the Chiral Binding Pocket.

A new generation of chiral gold(I) catalysts based on variations of complexes with JohnPhos-type ligands with a remote C2-symmetric 2,5-diarylpyrrolidine have been synthesized with different substitutions at the top and bottom aryl rings: from replacing the phosphine by a N-heterocyclic carbene (NHC) to increasing the steric hindrance with bis- or tris-biphenylphosphine scaffolds, or by directly attaching the C2-chiral pyrrolidine in the ortho-position of the dialkylphenyl phosphine. The new chiral gold(I) catalysts have been tested in the intramolecular [4+2] cycloaddition of arylalkynes with alkenes and in the atroposelective synthesis of 2-arylindoles. Interestingly, simpler catalysts with the C2-chiral pyrrolidine in the ortho-position of the dialkylphenyl phosphine led to the formation of opposite enantiomers. The chiral binding pockets of the new catalysts have been analyzed by DFT calculations. As revealed by non-covalent interaction plots, attractive non-covalent interactions between substrates and catalysts direct specific enantioselective folding. Furthermore, we have introduced the open-source tool NEST, specifically designed to account for steric effects in cylindrical-shaped complexes, which allows predicting experimental enantioselectivities in our systems.

Early glomerular filtration rates changes and risk of mortality in acute heart failure. The modifying role of admission renal function and decongestion.

BACKGROUND: The pathophysiology of changes in estimated glomerular filtration rate (eGFR) in acute heart failure (AHF) is complex and multifactorial. We evaluated the associated mortality risk of early changes in eGFR across baseline renal function on admission and early changes in natriuretic peptides in patients admitted with AHF. METHODS: We retrospectively evaluated 2,070 patients admitted with AHF. Renal dysfunction on admission was defined as eGFR<60 ml/min/1.73m2 and successful decongestion as NT-proBNP decreased >30% from baseline. We assessed the mortality risk associated with eGFR changes from baseline at 48-72 h after admission (ΔeGFR%) according to baseline renal function, and NT-proBNP changes at 48-72 h through Cox regression analyses. RESULTS: The mean age was 74.4 ± 11.2 years, and 930 (44.9%) were women. The proportion of admission eGFR<60 ml/min/1.73m2 and 48-72 h changes in NT-proBNP>30% were 50.5% and 32.8%, respectively. At a median follow-up of 1.75 years, 928 deaths were registered. In the whole sample, changes in renal function were not associated with mortality (p = 0.208). The adjusted analysis revealed that the risk of mortality related to ΔeGFR% was heterogeneous across baseline renal function and changes in NT-proBNP (p-value for interaction=0.003). ΔeGFR% was not associated with mortality in patients with baseline eGFR≥60 ml/min/1.73m2. In those with eGFR<60 ml/min/1.73m2, a decrease in eGFR was associated with higher mortality, particularly in those with a reduction in NT-proBNP<30%. CONCLUSION: In patients with AHF, early ΔeGFR% was associated with the risk of long-term mortality only in patients with renal dysfunction on admission and no early decline in NT-proBNP.

Bending oxygen saturation index and risk of worsening heart failure events in chronic heart failure.

AIMS: Bendopnea is a clinical symptom of advanced heart failure with uncertain prognostic value. We aimed to evaluate whether bendopnea and the change in oxygen saturation when bending forward (bending oxygen saturation index [BOSI]) are associated with adverse outcomes in ambulatory chronic heart failure (CHF) patients. METHODS AND RESULTS: We prospectively evaluated 440 subjects with symptomatic CHF. BOSI was defined as the difference between sitting and bending oxygen saturation (SpO2 ). The endpoint was the total number of worsening heart failure (WHF) events (heart failure hospitalization or urgent heart failure visit requiring parenteral diuretic therapy). The mean age was 74 ± 10 years, 257 (58.6%) were male, and 226 (51.4%) had a left ventricular ejection fraction <50%. Bendopnea was present in 94 (21.4%) patients, and 120 (27.3%) patients had a BOSI ≥-3%. The agreement between BOSI ≥-3% and bendopnea was moderate (Gwet's AC 0.482, p < 0.001). At a median (p25%-p75%) follow-up of 2.17 years (0.88-3.16), we registered 441 WHF events in 148 patients. After multivariable adjustment, BOSI was independently associated with the risk for total WHF episodes (overall, p < 0.001). Compared to improvement/no change in SpO2 when bending (BOSI 0%), those with BOSI ≥-3% showed an increased risk of WHF events (incidence rate ratio [IRR] 2.16, 95% confidence interval [CI] 1.67-2.79; p < 0.001). In contrast, bendopnea was not associated with the risk of total WHF episodes (IRR 1.04, 95% CI 0.83-1.31; p = 0.705). CONCLUSIONS: In ambulatory and stable CHF patients, BOSI ≥-3% and not bendopnea was independently associated with an increased risk of total (first and recurrent) WHF episodes. Awareness of SpO2 while assessing bendopnea may be a useful tool for predicting heart failure decompensations.

Nanosecond Pulsed Electric Field (nsPEF): Opening the Biotechnological Pandora's Box.

Nanosecond Pulsed Electric Field (nsPEF) is an electrostimulation technique first developed in 1995; nsPEF requires the delivery of a series of pulses of high electric fields in the order of nanoseconds into biological tissues or cells. They primary effects in cells is the formation of membrane nanopores and the activation of ionic channels, leading to an incremental increase in cytoplasmic Ca2+ concentration, which triggers a signaling cascade producing a variety of effects: from apoptosis up to cell differentiation and proliferation. Further, nsPEF may affect organelles, making nsPEF a unique tool to manipulate and study cells. This technique is exploited in a broad spectrum of applications, such as: sterilization in the food industry, seed germination, anti-parasitic effects, wound healing, increased immune response, activation of neurons and myocites, cell proliferation, cellular phenotype manipulation, modulation of gene expression, and as a novel cancer treatment. This review thoroughly explores both nsPEF's history and applications, with emphasis on the cellular effects from a biophysics perspective, highlighting the role of ionic channels as a mechanistic driver of the increase in cytoplasmic Ca2+ concentration.

Áreas problemáticas del ambiente educacional en estudiantes de Odontología según el cuestionario DREEM. Una revisión bibliográfica / Problematic areas of the educational environment in d entistry students according to the DREEM questionnaire. A bibliographic review

Introducción: El ambiente educacional (AE) se define como todo lo que rodea al estudiante en la academia. Conocer la percepción de los estudiantes sobre el AE es relevante para crear planes de estudios de calidad. El AE puede medirse con distintos instrumentos, uno de los cuales es el Dundee Ready Education Environment Measure (DREEM). En Odontología, este aspecto tiene un sentido especial, porque sus estudiantes se enfrentan a un AE complejo que varía durante los años. Por todo lo anterior, el objetivo de esta investigación fue identificar, basándonos en la bibliografía, las áreas más problemáticas del ambiente educacional según la percepción de los estudiantes de Odontología según el cuestionario DREEM.Materiales y métodos.Se realizó una revisión bibliográfica, con estrategias de búsquedas relacionadas con DREEM y educación dental en las bases de datos PubMed, EBSCO, Scielo y Web of Science, en el período comprendido entre enero de 2010 y octubre de 2020.Resultados.De 305 estudios, 11 cumplieron con los criterios de elegibilidad y fueron seleccionados para su análisis. La totalidad de los estudios examinó el AE con el cuestionario DREEM en estudiantes de Odontología de pregrado. De esto se extrajo que los ítems más problemáticos (puntuación menor de 2) fueron los ítems 3, 4, 42, 48, 25 y 9.Conclusión.Los estudiantes percibieron como áreas problemáticas aspectos relacionados con el estrés académico, docentes y el método de enseñanza. Estas dificultades son comunes dentro de las facultades de Odontología y la bibliografía ha propuesto múltiples soluciones con el fin de mejorar el AE. (AU)

Introduction: The educational environment (AE) is defined as everything that surrounds the student in the academy. Knowing the perception of students about AE is relevant to create quality study plans, this can be measured with different instruments, one of them is the Dundee Ready Education Environment Measure (DREEM). In dentistry this aspect has a special meaning because its students face a complex AE that changes over the years. Therefore, the objective of this research was to identify, based on the literature, the most problematic areas of the AE according to the perception of dental students based on the DREEM questionnaire.Materials and methods.A bibliographic review was carried out, with search strategies related to DREEM and dental education in the PubMed, EBSCO, Scielo and Web of Science databases; with articles published from January 2010 to October 2020.Results.Of 305 studies, 11 fulfilled the eligibility criteria and were selected for analysis. All the studies examined EA with the DREEM questionnaire in undergraduate dental students. From this it was extracted that the most problematic items (score less than 2) were items 3,4,42,48,25 and 9.Conclusion.Students perceived aspects related to academic stress, teachers and the teaching method as problem areas. These difficulties are common in dental schools and the literature has proposed multiple solutions in order to improve EA. (AU)

Utility of plasma CA125 as a proxy of intra-abdominal pressure in patients with acute heart failure.

AIMS: Increased intra-abdominal pressure (IAP) is now considered a potential contributor to organ damage and disease progression in acute heart failure (AHF). In this work, we aimed to determine if antigen carbohydrate 125 (CA125) is associated with IAP and to identify a cutpoint of CA125 useful for ruling out intra-abdominal hypertension (defined as IAP ≥ 12 mmHg). METHODS AND RESULTS: We prospectively evaluated a cohort of 53 patients admitted with AHF in which IAP was measured within the first 24-h of admission. The mean age was 80 ± 8 years, 31 (58.5%) were female, and 31 (58.5%) had left ventricular ejection fraction ≥50%. The median plasma levels of NT-proBNP and CA125 were 3830 pg/mL (2417-8929) and 45.8 U/mL (29.8-114.0), respectively. The median of IAP was 15 mmHg (11-17), and 39 (73%) patients had an IAP ≥ 12 mmHg. The diagnostic performance of CA125 for identifying an IAP ≥ 12 mmHg was tested using the receiving operating characteristic (ROC) curve. The cut-off for CA125 of 17.1 U/mL showed a sensitivity of 92%, a specificity of 50%, and an area under the ROC curve of 0.71. After multivariate adjustment, CA125 remained non-linearly and positively associated with higher IAP (P-value = 0.003), explaining almost 28% of the model's variability (R2: 27.6%). CONCLUSIONS: Patients with AHF and intra-abdominal hypertension had higher CA125 plasma levels. A baseline concentration of CA125 below 17.1 U/mL will increase the odds of identifying a subset of patients with normal IAP.

Carbohydrate antigen 125 and risk of heart failure readmissions in patients with heart failure and preserved ejection fraction.

We aimed to assess the association between CA125 and the long-term risk of total acute heart failure (AHF) admissions in patients with an index hospitalization with AHF and preserved ejection fraction (HFpEF). We prospectively included 2369 patients between 2008 and 2019 in three centers. CA125 and NT-proBNP were measured during early hospitalization and evaluated as continuous and categorized in quartiles (Q). Negative binomial regressions were used to assess the association with the risk of recurrent AHF admission. The mean age of the sample patients was 76.7 ± 9.5 years and 1443 (60.9%) were women. Median values of CA125 and NT-proBNP were 38.3 (19.0-90.0) U/mL, and 2924 (1590-5447) pg/mL, respectively. During a median follow-up of 2.2 (0.8-4.6) years, 1200 (50.6%) patients died, and 2084 AHF admissions occurred in 1029 (43.4%) patients. After a multivariate adjustment, CA125, but not NT-proBNP, was positively and non-linearly associated with the risk of cumulative AHF-readmission (p < 0.001). Compared to Q1, patients belonging to Q2, Q3, and Q4 showed a stepwise risk increase (IRR = 1.29, 95% CI 1.08-1.55, p = 0.006; IRR = 1.35, 95% CI 1.12-1.63, p = 0.002; and IRR = 1.62, 95% CI 01.34-1.96, p < 0.001, respectively). In conclusion, CA125 predicted the risk of long-term AHF-readmission burden in patients with HFpEF and a recent admission for AHF.

Effects of empagliflozin on CA125 trajectory in patients with chronic congestive heart failure.

INTRODUCTION: We aimed to evaluate the trajectory of two surrogates of fluid overload -antigen carbohydrate 125 (CA125) and amino-terminal pro-brain natriuretic peptide (NT-proBNP)- after the addition of oral empagliflozin to usual care in a cohort of patients with chronic heart failure (CHF) and type 2 diabetes (T2D). METHODS AND RESULTS: From October 2015 to February 2019, 60 ambulatory patients with CHF and T2D were retrospectively included. The primary endpoint was to assess the longitudinal trajectory of plasma levels of CA125 and NT-proBNP after empagliflozin initiation. Changes in quantitative variables were evaluated using linear mixed regression. Median CA125 and NT-proBNP at baseline were 17 (11-75) U/mL and 1662 (647-4230) pg/mL, respectively. A total of 510 outpatient visits were recorded [median (interquartile range) of visits per patient: 6 (4-11)] during a median of 1.78 years. We found a significant and steady decrease in the log of CA125 after empagliflozin initiation (p < 0.001). Conversely, the log of NT-proBNP predicted trajectory did not significantly change (p = 0.425). CONCLUSION: In this cohort of patients with CHF and T2D, empagliflozin initiation was associated with a significant decrease in CA125 levels without modifying the trajectory of NT-proBNP. Considering that CA125 has emerged as a surrogate marker of tissue congestion, we hypothesize that empagliflozin might predominantly promote extravascular decongestion.

Right Heart Dysfunction and Readmission Risk Across Left Ventricular Ejection Fraction Status in Patients With Acute Heart Failure.

BACKGROUND: Right heart dysfunction (RHD) parameters are increasingly important in heart failure (HF). This study aimed to evaluate the association of advanced RHD with the risk of recurrent admissions across the spectrum of left ventricular ejection fraction (LVEF). METHODS AND RESULTS: We included 3383 consecutive patients discharged for acute HF. Of them, in 1435 patients (42.4%), the pulmonary artery systolic pressure could not be measured accurately, leaving a final sample size of 1948 patients. Advanced RHD was defined as the combination of a ratio of tricuspid annular plane systolic excursion/pulmonary artery systolic pressure of less than 0.36 and significant tricuspid regurgitation (n = 196, 10.2%). Negative binomial regression analyses were used to evaluate the risk of recurrent admissions. At a median follow-up of 2.2 years (interquartile range 0.63-4.71), 3782 readmissions were registered in 1296 patients (66.5%). Patients with advanced RHD showed higher readmission rates, but only if the LVEF was 40% or greater (P < .001). In multivariable analyses, this differential association persisted for cardiovascular and HF recurrent admissions (P value for interaction = .015 and P = .016; respectively). Advanced RHD was independently associated with the risk of recurrent cardiovascular and HF admissions if HF with an LVEF of 40% or greater (incidence rate ratio 1.64, 95% confidence interval 1.18-2.26, P = .003; and incidence rate ratio 1.73; 95% confidence interval 1.25-2.41, P = .001;respectively). In contrast, it was not associated with readmission risks if the LVEF was less than 40%. CONCLUSIONS: After an admission for acute HF, advanced RHD was strongly associated with a higher risk of recurrent cardiovascular and HF admissions, but only in patients with an LVEF of 40% or greater.

Clinical utility of antigen carbohydrate 125 for planning the optimal length of stay in acute heart failure.

BACKGROUND: The optimal length of stay (LOS) in patients hospitalized for acute heart failure (AHF) remains controversial. Plasma antigen carbohydrate 125 (CA125) has emerged as a reliable proxy of congestion. We aimed to evaluate whether there is a differential impact of LOS on the risk of 6-month AHF readmission across CA125 levels. METHODS: This is a retrospective study that included 1,387 patients discharged for AHF in two third-level centers. CA125 was measured 48±24 h after admission. The association between CA125 and LOS with the risk of subsequent AHF readmission at 6 months was analyzed by Cox regression analysis accounting for death as a competing event. RESULTS: The median (IQR) age of the sample was 78 (69-83) years, 625 (41.1%) patients were women, and 832 (60%) exhibited preserved left ventricular ejection fraction. The median LOS and CA125 were 6 (4-9) days and 36 (17-83) U/mL, respectively. A total of 707 (51%) patients displayed high CA125 levels (≥35 U/mL). At 6 months, 87 deaths (6,3%) and 304 AHF readmissions (21,9%) were registered, respectively. A multivariate analysis revealed a differential effect of LOS on 6-month AHF readmission across CA125 levels (p-value for interaction=0.010). In those with CA125<35 U/mL, LOS≥7 days did not modify the risk (HR:1.31; 95% CI: 0.92-1.87, p=0.131). Conversely, in those with CA125≥35 U/mL, LOS≥7 days was associated with a lower risk of AHF readmission (HR:0.70; 95% CI: 0.51-0.98, p=0.036). CONCLUSIONS: In patients with AHF, high CA125 levels may identify those patients that benefit from a more prolonged hospitalization in terms of reducing the risk of mid-term AHF readmissions.

Right ventricular function and iron deficiency in acute heart failure.

AIMS: Iron deficiency (ID) is a frequent finding in patients with chronic and acute heart failure (AHF) along the full spectrum of left ventricular ejection fraction (LVEF). Iron deficiency has been related to ventricular systolic dysfunction, but its role in right ventricular function has not been evaluated. We sought to evaluate whether ID identifies patients with greater right ventricular dysfunction in the setting of AHF. METHODS AND RESULTS: We prospectively included 903 patients admitted with AHF. Right systolic function was evaluated by tricuspid annular plane systolic excursion (TAPSE) and the ratio TAPSE/pulmonary artery systolic pressure (TAPSE/PASP). Iron deficiency was defined, according to European Society of Cardiology criteria, as serum ferritin <100 mg/dL (absolute ID) or ferritin 100-299 mg/dL and transferrin saturation (TSAT) <20% (functional ID). The relationships among the exposures with right ventricular systolic function were evaluated by multivariate linear regression analyses. The mean age of the sample was 74.3 ± 10.6 years, 441 (48.8%) were female, 471 (52.2%) exhibited heart failure with preserved ejection fraction, and 677 (75.0%) showed ID. The mean LVEF, TAPSE, and TAPSE/PASP were 49 ± 15%, 18.6 ± 3.9 mm, and 0.45 ± 0.18, respectively. The median (interquartile range) amino-terminal pro-brain natriuretic peptide was 4015 (1807-8775) pg/mL. In a multivariable setting, lower TSAT and ferritin were independently associated with lower TAPSE (P < 0.05 for both comparisons). Transferrin saturation (P = 0.017), and not ferritin (P = 0.633), was independently associated with TAPSE/PASP. CONCLUSION: In AHF, proxies of ID were associated with right ventricular dysfunction. Further studies should confirm these findings and evaluate the pathophysiological facts behind this association.

Early urinary sodium trajectory and risk of adverse outcomes in acute heart failure and renal dysfunction.

INTRODUCTION AND OBJECTIVES: Urinary sodium (UNa+) has emerged as a useful biomarker of poor clinical outcomes in acute heart failure (AHF). Here, we sought to evaluate: a) the usefulness of a single early determination of UNa+ for predicting adverse outcomes in patients with AHF and renal dysfunction, and b) whether the change in UNa+ at 24hours (ΔUNa24h) adds any additional prognostic information over baseline values. METHODS: This is a post-hoc analysis of a multicenter, open-label, randomized clinical trial (IMPROVE-HF) (ClinicalTrials.gov NCT02643147) that randomized 160 patients with AHF and renal dysfunction on admission to a) the standard diuretic strategy, or b) a carbohydrate antigen 125-guided diuretic strategy. The primary end point was all-cause mortality and total all-cause readmissions. RESULTS: The mean age was 78±8 years, and the mean glomerular filtration rate was 34.0±8.5mL/min/1.73 m2. The median UNa+ was 90 (65-111) mmol/L. At a median follow-up of 1.73 years [interquartile range, 0.48-2.35], 83 deaths (51.9%) were registered, as well as 263 all-cause readmissions in 110 patients. UNa+ was independently associated with mortality (HR, 0.75; 95%CI, 0.65-0.87; P <.001) and all-cause readmissions (HR, 0.92; 95%CI, 0.88-0.96; P <.001). The prognostic usefulness of the ΔUNa24h varied according to UNa+ at admission (P for interaction <.05). The ΔUNa24h was inversely associated with both end points only in the group with UNa+ ≤ 50 mmol/L. Conversely, no effect was found in the group with UNa+> 50 mmol/L. CONCLUSIONS: In patients with AHF and renal dysfunction, a single early determination of UNa+ ≤ 50 mmol/L identifies patients with a higher risk of all-cause mortality and readmission. The ΔUNa24h adds prognostic information over baseline values only when UNa+ at admission is ≤ 50 mmol/L.

Effect of insulin on readmission for heart failure following a hospitalization for acute heart failure.

AIMS: Type 2 diabetes mellitus (T2DM) is common in patients with heart failure (HF) and is related with worse outcomes. Insulin treatment is associated with sodium and water retention, weight gain, and hypoglycaemia-all pathophysiological mechanisms related to HF decompensation. This study aimed to evaluate the association between insulin treatment and the risk of 1 year readmission for HF in patients discharged for acute HF. METHODS AND RESULTS: We prospectively included 2895 consecutive patients discharged after an episode of acute HF in a single tertiary hospital. Multivariable Cox regression, adapted for competing events, was used to assess the association between insulin treatment and 1 year readmission for HF in patients discharged after acute HF. Participants' mean age was 73.4 ± 11.2 years, 50.8% were women, 44.7% had T2DM [including 527 (18.2%) on insulin therapy], and 52.7% had preserved ejection fraction. At 1 year follow-up, 518 (17.9%) patients had died and 693 (23.9%) were readmitted for HF. The crude risk of readmission for HF was higher in patients on insulin, with no differences in 1 year mortality. After multivariable adjustment, patients on insulin were at significantly higher risk of 1 year readmission for HF than patients with diabetes who were not on insulin (hazard ratio 1.28; 95% confidence interval 1.04-1.59, P = 0.022) and patients without diabetes (hazard ratio 1.26; 95% confidence interval 1.02-1.55, P = 0.035). CONCLUSION: Following acute HF, patients with T2DM on insulin therapy are at increased risk of readmission for HF. Further studies unravelling the mechanisms behind this association are warranted.

Clinical profile and 1-year clinical outcomes of super elderly patients admitted with acute heart failure.

INTRODUCTION: There is scarce information about the clinical profile and prognosis of acute heart failure (AHF) at the extreme ranges of age. We aimed to evaluate the 1-year death (all-cause mortality and HF-death) and HF-rehospitalizations of patients ≥85 years admitted for AHF. METHODS: We prospectively evaluated a cohort of 3054 patients admitted with AHF from 2007 to 2018 in a third-level center. Age was categorized per 10-year categories (<65 years; 65-74 years, 75-84 years, and ≥85 years). The risk of mortality and HF-rehospitalizations across age categories was evaluated with Cox regression analysis and Cox regression adapted for competing events as appropriate. RESULTS: The mean age was 73.6 ± 11.2 years, 48.9% were female, and 52.8% had preserved left ventricular ejection fraction (HFpEF). A total of 414 (13.6%) patients were ≥85 years. Among this group of age, female sex and HFpEF phenotype were more frequent. At 1-year follow-up 667 all-cause deaths (22,1%), 311 HF-deaths (10.1%) and 693 HF-hospitalizations (22,7%) were recorded. After multivariable adjustment, and compared to patients <65 years, a stepwise increased risk of all-cause mortality and HF-death was found for each decade increase in age, especially for patients ≥85 years (HR=3.47; 95% CI: 2.49 - 4.84, p<0.001, HR=3.31; 95% CI: 1.95 - 5.63; p<0.001, respectively). This subgroup of patients also showed an increased risk of HF-rehospitalization (HR=1.58; 95% CI: 1.16 - 2.16, p=0.004). CONCLUSIONS: Super elderly patients admitted with AHF showed a dramatically increased risk of 1-year death. This subset of patients also shown an increased risk of 1-year HF-readmission.

Klebsiella pneumoniae Asparagine tDNAs Are Integration Hotspots for Different Genomic Islands Encoding Microcin E492 Production Determinants and Other Putative Virulence Factors Present in Hypervirulent Strains.

Due to the developing of multi-resistant and invasive hypervirulent strains, Klebsiella pneumoniae has become one of the most urgent bacterial pathogen threats in the last years. Genomic comparison of a growing number of sequenced isolates has allowed the identification of putative virulence factors, proposed to be acquirable mainly through horizontal gene transfer. In particular, those related with synthesizing the antibacterial peptide microcin E492 (MccE492) and salmochelin siderophores were found to be highly prevalent among hypervirulent strains. The determinants for the production of both molecules were first reported as part of a 13-kbp segment of K. pneumoniae RYC492 chromosome, and were cloned and characterized in E. coli. However, the genomic context of this segment in K. pneumoniae remained uncharacterized. In this work, we provided experimental and bioinformatics evidence indicating that the MccE492 cluster is part of a highly conserved 23-kbp genomic island (GI) named GIE492, that was integrated in a specific asparagine-tRNA gene (asn-tDNA) and was found in a high proportion of isolates from liver abscesses sampled around the world. This element resulted to be unstable and its excision frequency increased after treating bacteria with mitomycin C and upon the overexpression of the island-encoded integrase. Besides the MccE492 genetic cluster, it invariably included an integrase-coding gene, at least seven protein-coding genes of unknown function, and a putative transfer origin that possibly allows this GI to be mobilized through conjugation. In addition, we analyzed the asn-tDNA loci of all the available K. pneumoniae assembled chromosomes to evaluate them as GI-integration sites. Remarkably, 73% of the strains harbored at least one GI integrated in one of the four asn-tDNA present in this species, confirming them as integration hotspots. Each of these tDNAs was occupied with different frequencies, although they were 100% identical. Also, we identified a total of 47 asn-tDNA-associated GIs that were classified into 12 groups of homology differing in theencoded functionalities but sharing with GIE492 a conserved recombination module and potentially its mobility features. Most of these GIs encoded factors with proven or potential role in pathogenesis, constituting a major reservoir of virulence factors in this species.

Anatomy, histochemistry, and immunohistochemistry of the olfactory subsystems in mice.

The four regions of the murine nasal cavity featuring olfactory neurons were studied anatomically and by labeling with lectins and relevant antibodies with a view to establishing criteria for the identification of olfactory subsystems that are readily applicable to other mammals. In the main olfactory epithelium and the septal organ the olfactory sensory neurons (OSNs) are embedded in quasi-stratified columnar epithelium; vomeronasal OSNs are embedded in epithelium lining the medial interior wall of the vomeronasal duct and do not make contact with the mucosa of the main nasal cavity; and in Grüneberg's ganglion a small isolated population of OSNs lies adjacent to, but not within, the epithelium. With the exception of Grüneberg's ganglion, all the tissues expressing olfactory marker protein (OMP) (the above four nasal territories, the vomeronasal and main olfactory nerves, and the main and accessory olfactory bulbs) are also labeled by Lycopersicum esculentum agglutinin, while Ulex europaeus agglutinin I labels all and only tissues expressing Gαi2 (the apical sensory neurons of the vomeronasal organ, their axons, and their glomerular destinations in the anterior accessory olfactory bulb). These staining patterns of UEA-I and LEA may facilitate the characterization of olfactory anatomy in other species. A 710-section atlas of the anatomy of the murine nasal cavity has been made available on line.

Estudio preliminar sobre el fenotipo de acetilador de los amerindios Teribes / Preliminar study on the phenotype of acetylator of Teribe Amerindians

El estudio de la capacidad de acetilación en 62 voluntarios teribes, procedentes de Sieykin, Sieyic y Santa Rosa, demonstró que 48.4% eran acetiladores rápidos y 51.6%, acetiladores lentos. Al comprobar estos resultados con los que obtuvimos en una población cuna, en la cual encontramos que el 78% era de acetiladores rápidos, se observa que tanto la distribución de los sujetos estudiados, según el porcentaje de isoniacida que acetilaron, como el porcentaje de acetiladores lentos y rápidos indican que, en ambos grupos, existen diferencias en la actividad de la N-acetiltransferasa. Estos resultados sugieren que pueden existir diferencias fundamentales entre los diferentes grupos amerindios, en la habilidade de biotransformar los medicamentos