Pore-forming peptide C14R exhibits potent antifungal activity against clinical isolates of Candida albicans and Candida auris.

Introduction: Invasive candidiasis is a global public health problem as it poses a significant threat in hospital-settings. The aim of this study was to evaluate C14R, an analog derived from peptide BP100, as a potential antimicrobial peptide against the prevalent opportunistic yeast Candida albicans and the emergent multidrug-resistant yeast Candida auris. Methods: Antifungal susceptibility testing of C14R against 99 C. albicans and 105 C. auris clinical isolates from Colombia, was determined by broth microdilution. Fluconazole was used as a control antifungal. The synergy between C14R and fluconazole was assessed in resistant isolates. Assays against fungal biofilm and growth curves were also carried out. Morphological alterations of yeast cell surface were evaluated by scanning electron microscopy. A permeability assay verified the pore-forming ability of C14R. Results: C. albicans and C. auris isolates had a geometric mean MIC against C14R of 4.42 µg/ml and 5.34 µg/ml, respectively. Notably, none of the isolates of any species exhibited growth at the highest evaluated peptide concentration (200 µg/ml). Synergistic effects were observed when combining the peptide and fluconazole. C14R affects biofilm and growth of C. albicans and C. auris. Cell membrane disruptions were observed in both species after treatment with the peptide. It was confirmed that C14R form pores in C. albicans' membrane. Discussion: C14R has a potent antifungal activity against a large set of clinical isolates of both C. albicans and C. auris, showing its capacity to disrupt Candida membranes. This antifungal activity remains consistent across isolates regardless of their clinical source. Furthermore, the absence of correlation between MICs to C14R and resistance to fluconazole indicates the peptide's potential effectiveness against fluconazole-resistant strains. Our results suggest the potential of C14R, a pore-forming peptide, as a treatment option for fungal infections, such as invasive candidiasis, including fluconazole and amphotericin B -resistant strains.

Identification of a potent and selective LAPTc inhibitor by RapidFire-Mass Spectrometry, with antichagasic activity.

BACKGROUND: Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and leads to ~10,000 deaths each year. Nifurtimox and benznidazole are the only two drugs available but have significant adverse effects and limited efficacy. New chemotherapeutic agents are urgently required. Here we identified inhibitors of the acidic M17 leucyl-aminopeptidase from T. cruzi (LAPTc) that show promise as novel starting points for Chagas disease drug discovery. METHODOLOGY/PRINCIPAL FINDINGS: A RapidFire-MS screen with a protease-focused compound library identified novel LAPTc inhibitors. Twenty-eight hits were progressed to the dose-response studies, from which 12 molecules inhibited LAPTc with IC50 < 34 µM. Of these, compound 4 was the most potent hit and mode of inhibition studies indicate that compound 4 is a competitive LAPTc inhibitor, with Ki 0.27 µM. Compound 4 is selective with respect to human LAP3, showing a selectivity index of >500. Compound 4 exhibited sub-micromolar activity against intracellular T. cruzi amastigotes, and while the selectivity-window against the host cells was narrow, no toxicity was observed for un-infected HepG2 cells. In silico modelling of the LAPTc-compound 4 interaction is consistent with the competitive mode of inhibition. Molecular dynamics simulations reproduce the experimental binding strength (-8.95 kcal/mol), and indicate a binding mode based mainly on hydrophobic interactions with active site residues without metal cation coordination. CONCLUSIONS/SIGNIFICANCE: Our data indicates that these new LAPTc inhibitors should be considered for further development as antiparasitic agents for the treatment of Chagas disease.

Insights into the Adsorption Mechanisms of the Antimicrobial Peptide CIDEM-501 on Membrane Models.

CIDEM-501 is a hybrid antimicrobial peptide rationally designed based on the structure of panusin and panulirin template peptides. The new peptide exhibits significant antibacterial activity against multidrug-resistant pathogens (MIC = 2-4 µM) while conserving no toxicity in human cell lines. We conducted molecular dynamics (MD) simulations using the CHARMM-36 force field to explore the CIDEM-501 adsorption mechanism with different membrane compositions. Several parameters that characterize these interactions were analyzed to elucidate individual residues' structural and thermodynamic contributions. The membrane models were constructed using CHARMM-GUI, mimicking the bacterial and eukaryotic phospholipid compositions. Molecular dynamics simulations were conducted over 500 ns, showing rapid and highly stable peptide adsorption to bacterial lipids components rather than the zwitterionic eucaryotic model membrane. A predominant peptide orientation was observed in all models dominated by an electric dipole. The peptide remained parallel to the membrane surface with the center loop oriented to the lipids. Our findings shed light on the antibacterial activity of CIDEM-501 on bacterial membranes and yield insights valuable for designing potent antimicrobial peptides targeting multi- and extreme drug-resistant bacteria.

The Designed Pore-Forming Antimicrobial Peptide C14R Combines Excellent Activity against the Major Opportunistic Human Pathogen Pseudomonas aeruginosa with Low Cytotoxicity.

The diminishing portfolio of mankind's available antibiotics urges science to develop novel potent drugs. Here, we present a peptide fitting the typical blueprint of amphipathic and membrane-active antimicrobial peptides, denominated C14R. This 2 kDa peptide consists of 16 amino acid residues, with seven being either hydrophobic, aromatic, or non-polar, and nine being polar or positively charged, strictly separated on opposite sides of the predicted α-helix. The affinity of the peptide C14R to P. aeruginosa membranes and its intrinsic tendency to productively insert into membranes of such composition were analyzed by dynamic simulations. Its biological impact on the viability of two different P. aeruginosa reference strains was demonstrated by determining the minimal inhibitory concentrations (MICs), which were found to be in the range of 10-15 µg/mL. C14R's pore-forming capability was verified in a permeabilization assay based on the peptide-triggered uptake of fluorescent dyes into the bacterial cells. Finally, the peptide was used in radial diffusion assays, which are commonly used for susceptibility testing of antimicrobial peptides in clinical microbiology. In comparison to reference strains, six clinical P. aeruginosa isolates were clearly affected, thereby paving the way for further in-depth analyses of C14R as a promising new AMP drug in the future.

Identification and Characterization of Three New Antimicrobial Peptides from the Marine Mollusk Nerita versicolor (Gmelin, 1791).

Mollusks have been widely investigated for antimicrobial peptides because their humoral defense against pathogens is mainly based on these small biomolecules. In this report, we describe the identification of three novel antimicrobial peptides from the marine mollusk Nerita versicolor. A pool of N. versicolor peptides was analyzed with nanoLC-ESI-MS-MS technology, and three potential antimicrobial peptides (Nv-p1, Nv-p2 and Nv-p3) were identified with bioinformatical predictions and selected for chemical synthesis and evaluation of their biological activity. Database searches showed that two of them show partial identity to histone H4 peptide fragments from other invertebrate species. Structural predictions revealed that they all adopt a random coil structure even when placed near a lipid bilayer patch. Nv-p1, Nv-p2 and Nv-p3 exhibited activity against Pseudomonas aeruginosa. The most active peptide was Nv-p3 with an inhibitory activity starting at 1.5 µg/mL in the radial diffusion assays. The peptides were ineffective against Klebsiella pneumoniae, Listeria monocytogenes and Mycobacterium tuberculosis. On the other hand, these peptides demonstrated effective antibiofilm action against Candida albicans, Candida parapsilosis and Candida auris but not against the planktonic cells. None of the peptides had significant toxicity on primary human macrophages and fetal lung fibroblasts at effective antimicrobial concentrations. Our results indicate that N. versicolor-derived peptides represent new AMP sequences and have the potential to be optimized and developed into antibiotic alternatives against bacterial and fungal infections.

Xanthatin and 8-epi-xanthatin as new potential colchicine binding site inhibitors: a computational study.

CONTEXT: Phytocompounds xanthatin and 8-epi-xanthatin, obtained from Xanthium chinese Mill, showed antitumoral activity in vitro related to the microtubules destabilizing properties of these phytocompounds. Five binding sites for microtubule destabilizing agents have been characterized on tubulin by high-resolution X-ray crystallography: vinca domain, colchicine, pironetin, maytansine site, and more recently, the seventh site. This work aims to develop a comprehensive computational strategy to understand and eventually predict the interaction between xanthatin and 8-epi-xanthatin with the destabilizing-antimitotic binding domain of the tubulin heterodimer. In addition, we propose a putative binding site for these phytocompounds into the microtubule destabilizing binding sites on the tubulin heterodimer. Xanthanolides showed higher stability in the colchicine and pironetin binding sites, whit a greater affinity for the former. In addition, we found that xanthanolides and non-classical colchicine binding site inhibitors share a high structural similarity. METHODS: The 3D structures for xanthatin and 8-epi-xanthatin were obtained using DFT with the hybrid functional B3LYP and the base 6-31G (d,p), implemented in Gaussian 09. The 3D coordinates for tubulin proteins were downloaded from PDB. The complexes tubulin-xanthanolides were predicted using a Monte-Carlo iterated search combined with the BFGS gradient-based optimizer implemented in the AutoDock Vina. The xanthanolides-tubulin complexes were energy minimized by molecular dynamics simulations at vacuum, and their stabilities were evaluated by solvated molecular dynamics simulations during 100 ns. All molecular dynamics simulations were performed using the conjugate gradient method implemented in NAMD2 and CHARMM36 forcefield.

Treatment-refractory heart failure as a manifestation of aortic arch atresia.

BACKGROUND: Distal segment atresia (isthmus) is an extremely rare anatomical variant of obstructive aortic arch anomalies. CASE REPORT: We present the case of a newborn who, at 48 hours of life, presented a clinical picture of heart failure. The initial echocardiogram showed a congenital interrupted aortic arch type A, patent ductus arteriosus, and ventricular septal defect. Prostaglandins were initially indicated. Subsequently, a second echocardiogram showed the absence of ductus arteriosus; the CT angiography study confirmed this finding and revealed blood flow to the descending aorta through small intercostal blood vessels. The possibility of atresia of the distal segment (isthmus) of the aortic arch was considered and confirmed at the time of surgery. CONCLUSIONS: Aortic atresia should be considered a diagnostic possibility in the presence of type A interrupted aortic arch since the hemodynamic behavior between them is similar. Surgical medical treatment should be individualized since this condition is frequently an emergency in the neonatal period. However, this is not always the case, as other cases have been reported in schoolchildren and adults.

INTRODUCCIÓN: La atresia de segmento distal (istmo) de arco aórtico es una variante anatómica extremadamente rara de las anomalías obstructivas del arco aórtico. CASO CLÍNICO: Se presenta el caso de un recién nacido que a las 48 horas de vida presentó un cuadro clínico de insuficiencia cardiaca. El estudio de ecocardiograma inicial mostró una anomalía congénita de interrupción de arco aórtico tipo A, conducto arterioso y comunicación interventricular. De inicio se indicaron prostaglandinas. Posteriormente, el segundo ecocardiograma mostró la ausencia del conducto arterioso; el estudio de angiotomografía confirmó este hallazgo y también reveló flujo sanguíneo hacia aorta descendente a través de pequeños vasos sanguíneos intercostales. Se consideró la posibilidad de atresia del segmento distal (istmo) de arco aórtico y se confirmó al momento del acto quirúrgico. CONCLUSIONES: La atresia aórtica debe ser considerada como posibilidad diagnóstica en presencia de interrupción de arco aórtico tipo A, ya que el comportamiento hemodinámico entre ellos es similar. El tratamiento médico quirúrgico debe individualizarse, ya que es frecuente que sea una urgencia en el periodo neonatal. Sin embargo, no sucede así siempre, ya que se han reportado casos en escolares y adultos.

Treatment-refractory heart failure as a manifestation of aortic arch atresia / Falla cardiaca refractaria a tratamiento como manifestación de atresia de arco aórtico

Abstract Background: Distal segment atresia (isthmus) is an extremely rare anatomical variant of obstructive aortic arch anomalies. Case report: We present the case of a newborn who, at 48 hours of life, presented a clinical picture of heart failure. The initial echocardiogram showed a congenital interrupted aortic arch type A, patent ductus arteriosus, and ventricular septal defect. Prostaglandins were initially indicated. Subsequently, a second echocardiogram showed the absence of ductus arteriosus; the CT angiography study confirmed this finding and revealed blood flow to the descending aorta through small intercostal blood vessels. The possibility of atresia of the distal segment (isthmus) of the aortic arch was considered and confirmed at the time of surgery. Conclusions: Aortic atresia should be considered a diagnostic possibility in the presence of type A interrupted aortic arch since the hemodynamic behavior between them is similar. Surgical medical treatment should be individualized since this condition is frequently an emergency in the neonatal period. However, this is not always the case, as other cases have been reported in schoolchildren and adults.

Resumen Introducción: La atresia de segmento distal (istmo) de arco aórtico es una variante anatómica extremadamente rara de las anomalías obstructivas del arco aórtico. Caso clínico: Se presenta el caso de un recién nacido que a las 48 horas de vida presentó un cuadro clínico de insuficiencia cardiaca. El estudio de ecocardiograma inicial mostró una anomalía congénita de interrupción de arco aórtico tipo A, conducto arterioso y comunicación interventricular. De inicio se indicaron prostaglandinas. Posteriormente, el segundo ecocardiograma mostró la ausencia del conducto arterioso; el estudio de angiotomografía confirmó este hallazgo y también reveló flujo sanguíneo hacia aorta descendente a través de pequeños vasos sanguíneos intercostales. Se consideró la posibilidad de atresia del segmento distal (istmo) de arco aórtico y se confirmó al momento del acto quirúrgico. Conclusiones: La atresia aórtica debe ser considerada como posibilidad diagnóstica en presencia de interrupción de arco aórtico tipo A, ya que el comportamiento hemodinámico entre ellos es similar. El tratamiento médico quirúrgico debe individualizarse, ya que es frecuente que sea una urgencia en el periodo neonatal. Sin embargo, no sucede así siempre, ya que se han reportado casos en escolares y adultos.

Toward a More Comprehensive View of α-Amylase across Decapods Crustaceans.

Decapod crustaceans are a very diverse group and have evolved to suit a wide variety of diets. Alpha-amylases enzymes, responsible for starch and glycogen digestion, have been more thoroughly studied in herbivore and omnivore than in carnivorous species. We used information on the α-amylase of a carnivorous lobster as a connecting thread to provide a more comprehensive view of α-amylases across decapods crustaceans. Omnivorous crustaceans such as shrimps, crabs, and crayfish present relatively high amylase activity with respect to carnivorous crustaceans. Yet, contradictory results have been obtained and relatively high activity in some carnivores has been suggested to be a remnant trait from ancestor species. Here, we provided information sustaining that high enzyme sequence and overall architecture conservation do not allow high changes in activity, and that differences among species may be more related to number of genes and isoforms, as well as transcriptional and secretion regulation. However, recent evolutionary analyses revealed that positive selection might have also occurred among distant lineages with feeding habits as a selection force. Some biochemical features of decapod α-amylases can be related with habitat or gut conditions, while less clear patterns are observed for other enzyme properties. Likewise, while molt cycle variations in α-amylase activity are rather similar among species, clear relationships between activity and diet shifts through development cannot be always observed. Regarding the adaptation of α-amylase to diet, juveniles seem to exhibit more flexibility than larvae, and it has been described variation in α-amylase activity or number of isoforms due to the source of carbohydrate and its level in diets, especially in omnivore species. In the carnivorous lobster, however, no influence of the type of carbohydrate could be observed. Moreover, lobsters were not able to fine-regulate α-amylase gene expression in spite of large changes in carbohydrate content of diet, while retaining some capacity to adapt α-amylase activity to very low carbohydrate content in the diets. In this review, we raised arguments for the need of more studies on the α-amylases of less studied decapods groups, including carnivorous species which rely more on dietary protein and lipids, to broaden our view of α-amylase in decapods crustaceans.

First trimester screening for preterm and term pre-eclampsia by maternal characteristics and biophysical markers in a low-risk population.

AIM: To develop a combined predictive model for preterm and term pre-eclampsia (PE) during the first trimester of pregnancy. METHODS: This investigation was a nested case-control study in singleton pregnancies at the Maternal-Fetal Medicine Unit, University of Chile Hospital. A priori risks for preterm and term PE were calculated by multivariate logistic regression analyses. Biophysical markers were log10 -transformed and expressed as multiples of the median. A multivariate logistic regression analysis was used to estimate a combined predictive model of preterm and term PE. Detection rates at different cut-off points were determined by a receiver operator curve analysis of a posteriori risks. RESULTS: First trimester mean arterial pressure and uterine artery Doppler pulsatility index were significantly higher in women who develop PE than in the unaffected group. The detection rate of preterm PE based on maternal characteristics and biophysical markers was 72% at a 10% false-positive rate, corresponding to a cut-off risk of 1 in 50. The detection rate for term PE was 30% at a 10% false-positive rate. CONCLUSION: Preterm PE can be predicted by a combination of maternal characteristics and biophysical markers. However, first trimester screening is less valuable for term PE.

Mesoporous silica nanoparticles decorated with polycationic dendrimers for infection treatment.

This work aims to provide an effective and novel solution for the treatment of infection by using nanovehicles loaded with antibiotics capable of penetrating the bacterial wall, thus increasing the antimicrobial effectiveness. These nanosystems, named "nanoantibiotics", are composed of mesoporous silica nanoparticles (MSNs), which act as nanocarriers of an antimicrobial agent (levofloxacin, LEVO) localized inside the mesopores. To provide the nanosystem of bacterial membrane interaction capability, a polycationic dendrimer, concretely the poly(propyleneimine) dendrimer of third generation (G3), was covalently grafted to the external surface of the LEVO-loaded MSNs. After physicochemical characterization of this nanoantibiotic, the release kinetics of LEVO and the antimicrobial efficacy of each released dosage were evaluated. Besides, internalization studies of the MSNs functionalized with the G3 dendrimer were carried out, showing a high penetrability throughout Gram-negative bacterial membranes. This work evidences that the synergistic combination of polycationic dendrimers as bacterial membrane permeabilization agents with LEVO-loaded MSNs triggers an efficient antimicrobial effect on Gram-negative bacterial biofilm. These positive results open up very promising expectations for their potential application in new infection therapies. STATEMENT OF SIGNIFICANCE: Seeking new alternatives to current available treatments of bacterial infections represents a great challenge in nanomedicine. This work reports the design and optimization of a new class of antimicrobial agent, named "nanoantibiotic", based on mesoporous silica nanoparticles (MSNs) decorated with polypropyleneimine dendrimers of third generation (G3) and loaded with levofloxacin (LEVO) antibiotic. The covalently grafting of these G3 dendrimers to MSNs allows an effective internalization in Gram-negative bacteria. Furthermore, the LEVO loaded into the mesoporous cavities is released in a sustained manner at effective antimicrobial dosages. The novelty and originality of this manuscript relies on proving that the synergistic combination of bacteria-targeting and antimicrobial agents into a unique nanosystem provokes a remarkable antimicrobial effect against bacterial biofilm.

Risk of perinatal death in early-onset intrauterine growth restriction according to gestational age and cardiovascular Doppler indices: a multicenter study.

OBJECTIVE: To assess the value of gestational age and cardiovascular Doppler indices in predicting perinatal mortality in a multicenter cohort of early-onset intrauterine growth-restricted (IUGR) fetuses. METHODS: A multicenter prospective cohort study including 157 early-onset (<34 weeks) IUGR cases with abnormal umbilical artery (UA) Doppler was conducted. Cardiovascular assessment included the ductus venosus (DV), the aortic isthmus flow index (IFI), and the myocardial performance index (MPI). Isolated and combined values to predict the risk of perinatal death were evaluated by logistic regression and by decision tree analysis, where the gestational age at delivery, UA, and middle cerebral artery (MCA) were also included as covariates. RESULTS: Perinatal mortality was 17% (27/157). All parameters were significantly associated with perinatal death, with individual odds ratios (OR) of 25.2 for gestational age below 28 weeks, 12.1 for absent/reversed DV atrial flow, 5.3 for MCA pulsatility index <5th centile, 4.6 for UA absent/reversed diastolic end-flow, 1.8 for IFI <5th centile, and 1.6 for MPI >95th centile. Decision tree analysis identified gestational age at birth as the best predictor of death (<26 weeks, 93% mortality; 26-28 weeks, 29% mortality, and >28 weeks, 3% mortality). Between 26 and 28 weeks, DV atrial flow allowed further stratification between high (60%) and low risk (18%) of mortality. CONCLUSIONS: Gestational age largely determines the risk of perinatal mortality in early-onset IUGR before 26 weeks and later than 28 weeks of gestation. The DV may improve clinical management by stratifying the probability of death between 26 and 28 weeks of gestation.

[Recurrent Impetigo Herpetiformis: successfully managed with ciclosporine. Report of one case]. / Impétigo herpetiforme recurrente: manejo exitoso con ciclosporina.

Impetigo Herpetiformis is a high-risk gestational skin disease that represents a risk for both the mother and offspring. Its management is based on multisystemic support and maternal steroid therapy. When these measures are insufficient to control the disease, the association of ciclosporine to the treatment has been proposed. We report a 24 year-old woman with a 16 weeks pregnancy, that presented with Impetigo Herpetiformis. The disease was refractory to the use of steroids, the patient had a metabolic decompensation and a dehydration with electrolyte imbalance. Therefore, treatment with ciclosporine was initiated and a rapid regression of the lesions was observed. Gestation was maintained, with a good perinatal outcome.

Estenosis pieloureteral: experiencia clínica en niños / Ureteropelvic stenosis: clinical experience in childhood

Se analiza la experiencia clínica de 13 pacientes portadores de Estenosis Pieloureteral. En 11 pacientes se efectuó pieloplastía de Anderson-Hynes con un caso de reintervención por obstrucción anastomosis. El porcentaje de nefrectomía es de un 30%. Los resultados de pieloplastía fueron excelentes en el 60%. Bueno en el 30% y manlo en el 10%. La función renal evaluada con cintigrama en 7 pacientes fue buena. El porcentaje de parénquina en los polos aumentó en 3 pacientes