Chronic kidney disease and acute kidney injury in the COVID-19 Spanish outbreak.

BACKGROUND: Novel coronavirus disease 2019 (COVID-19) emerged in Wuhan and rapidly spread, affecting >10 million cases worldwide. Caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and primarily manifesting as an acute respiratory failure with interstitial and alveolar pneumonia, it can also affect multiple organs. Kidney involvement was underestimated in early reports and its role remains controversial. The aim of this study was to analyse the role of kidney damage in COVID-19 outcome. METHODS: This is a prospective cohort study of 1603 consecutive patients admitted in a University Reference Hospital in the heart of the European outbreak. RESULTS: Median age was 64 years, 40.4% were female, 15.2% presented diabetes mellitus, 35.7% hypertension and 20.3% obesity. On admission, the prevalence of elevated serum creatinine (sCr), proteinuria, leucocyturia and haematuria were 21.0, 37.8, 31.8 and 45.6%, respectively. In total, 43.5% of those with an elevated sCr had previous chronic kidney disease (CKD) and 11.4% of those with normal sCr developed an in-hospital acute kidney injury (AKI); 17 patients needed acute haemodialysis; and 197 patients died during hospitalization. Cox proportional hazard regression confirmed that elevated baseline sCr [hazard ratio (95% confidence interval) 2.40 (1.79-3.22)], previous CKD [1.59 (1.06-2.37)], haematuria [1 + 1.68 (0.92-3.06), 2-3 + 2.69 (1.49-4.87)] and in-hospital AKI [1.50 (0.92-2.44)] were independent risk factors for in-hospital death after adjusting for age, sex and comorbidity. CONCLUSION: The prevalence of acute and chronic kidney disease on admission and in-hospital AKI is higher than previously reported in Wuhan, and is associated with high in-hospital mortality. We should increase our awareness towards kidney involvement and design specific strategies for management of COVID-19 in these patients.

A prospective survey of Aspergillus spp. in respiratory tract samples: Species identification and susceptibility patterns.

We analyzed the species distribution and susceptibility patterns of 433 strains of Aspergillus spp. isolated from respiratory samples of 419 in-patients included in multicenter prospective study (FUNGAE-IFI) between July 2014 and October 2015. Identification was carried out by conventional methods at each participating center and by molecular sequencing of a portion of the ß-tubulin gene at one of the centers. In vitro susceptibility was evaluated by broth microdilution methods and using the E-test (for cryptic species). Species identified included 249 A. fumigatus sensu stricto, 60 A. terreus sensu stricto, 47 A. flavus sensu stricto, 44 A. tubingensis, 18 A. niger sensu stricto , five A. nidulans sensu stricto, three A. tamarii, two A. calidoustus, two A. carneus, one A. acuelatus, one A. carbonarius, and one A. sydowii. Cryptic species were found in 12.5% of isolates (n = 54). The frequency of non-wild-type isolates for amphotericin B was 3.4% (n = 15) of the isolates tested and for azoles 3% (n = 10). None of the Aspergillus spp. were non-wild type to echinocandins. Of the 54 cryptic species only two strains were non-wild-type strains by microdilution method (3.7%) (two A. tubingensis, one to amphotericin B and another one to voriconazole) and by E-test method five strains of A. tubingensis showed high minimal inhibitory concentration (MIC) to amphotericin B (11.4%) and five to azoles (12.1%), one A. calidoustus strain showed high MICs for three azoles (50%), A. carneus to itraconazole (100%) and A. sydowii to amphotericin B and itraconazole (100%). These results provide relevant information on susceptibility patterns, frequency, and epidemiology of species involved in respiratory tract samples and of the incidence of recently described cryptic species.

[Characterization of hospitalized patients with acute kidney injury associated with COVID-19 in Spain: Renal replacement therapy and mortality. FRA-COVID SEN Registry Data]. / Caracterización de la población con fracaso renal agudo durante la hospitalización por COVID-19 en España: tratamiento renal sustitutivo y mortalidad. Datos del Registro FRA-COVID SEN.

Background and objectives: Acute kidney injury (AKI) is common among hospitalized patients with COVID-19 and associated with worse prognosis. The Spanish Society of Nephrology created the AKI-COVID Registry to characterize the population admitted for COVID-19 that developed AKI in Spanish hospitals. The need of renal replacement therapy (RRT) therapeutic modalities, and mortality in these patients were assessed. Material and method: In a retrospective study, we analyzed data from the AKI-COVID Registry, which included patients hospitalized in 30 Spanish hospitals from May 2020 to November 2021. Clinical and demographic variables, factors related to the severity of COVID-19 and AKI, and survival data were recorded. A multivariate regression analysis was performed to study factors related to RRT and mortality. Results: Data from 730 patients were recorded. A total of 71.9% were men, with a mean age of 70 years (60-78), 70.1% were hypertensive, 32.9% diabetic, 33.3% with cardiovascular disease and 23.9% had some degree of chronic kidney disease (CKD). Pneumonia was diagnosed in 94.6%, requiring ventilatory support in 54.2% and admission to the ICU in 44.1% of cases.The median time from the onset of COVID-19 symptoms to the appearance of AKI (37.1% KDIGO I, 18.3% KDIGO II, 44.6% KDIGO III) was 6 days (4-10). A total of 235 (33.9%) patients required RRT: 155 patients with continuous renal replacement therapy, 89 alternate-day dialysis, 36 daily dialysis, 24 extended hemodialysis and 17 patients with hemodiafiltration. Smoking habit (OR 3.41), ventilatory support (OR 20.2), maximum creatinine value (OR 2.41) and time to AKI onset (OR 1.13) were predictors of the need for RRT; age was a protective factor (0.95). The group without RRT was characterized by older age, less severe AKI, shorter kidney injury onset and recovery time (p < 0.05). 38.6% of patients died during hospitalization; serious AKI and RRT were more frequent in the death group. In the multivariate analysis, age (OR 1.03), previous chronic kidney disease (OR 2.21), development of pneumonia (OR 2.89), ventilatory support (OR 3.34) and RRT (OR 2.28) were predictors of mortality while chronic treatment with ARBs was identified as a protective factor (OR 0.55). Conclusions: Patients with AKI during hospitalization for COVID-19 had a high mean age, comorbidities and severe infection. We defined two different clinical patterns: an AKI of early onset, in older patients that resolves in a few days without the need for RRT; and another more severe pattern, with greater need for RRT, and late onset, which was related to greater severity of the infectious disease. The severity of the infection, age and the presence of CKD prior to admission were identified as risk factors for mortality in these patients. In addition chronic treatment with ARBs was identified as a protective factor for mortality.

Epidemiology of Fabry disease in patients in hemodialysis in the Madrid community.

This study screened for Fabry disease (FD) in patients in hemodialysis (HD) in the region of Madrid (CAM) with a cross-sectional design to evaluate HD-prevalent patients, followed by a three-year period prospective design to analyze HD-incident patients. INCLUSION CRITERIA: patients older than 18 years on HD in the CAM, excluding patients diagnosed with any other hereditary disease with renal involvement different from FD, that sign the Informed Consent (IC). EXCLUSION CRITERIA: underaged patients or not agreeing or not being capable of signing the IC. RESULTS: 3470 patients were included, 63% males and with an average age of 67.9±9.7 years. 2357 were HD-prevalent patients and 1113 HD-incident patients. For HD-prevalent patients, average time in HD was 45.2 months (SD 51.3), in HD-incident patients proteinuria was present in 28.4%. There were no statistical differences in plasmatic alpha-galactosidase A (α-GAL-A) activity or Lyso-GL-3 values when comparing HD-prevalent and HD-incident populations and neither between males and females. A genetic study was performed in 87 patients (2.5% of patients): 60 male patients with decreased enzymatic activity and 27 female patients either with a decreased GLA activity, increased Lyso-Gl3 levels or both. The genetic variants identified were: p.Asp313Tyr (4 patients), p.Arg220Gln (3 patients) and M290I (1 patient). None of the identified variants is pathogenic. CONCLUSIONS: 76% of HD Centers of the CAM participated in the study. This is the first publication to describe the prevalence of FD in the HD-population of a region of Spain as well as its average α-GAL-A-activity and plasmatic Lyso-Gl3 levels. It is also the first study that combines a cross-sectional design with a prospective follow-up design. This study has not identified any FD patient.

[Follow-up of alcohol and/or cocaine dependents after their discharge from a therapeutic community: a pilot study]. / Seguimiento de dependientes del alcohol y/o de la cocaína después de su salida de una Comunidad Terapéutica: estudio piloto.

UNLABELLED: In Spain, the Therapeutic Community (TC) constitutes a common model of treatment in the field of addictions, although there hardly exists any investigation about its efficiency and the persistence of its attainments. AIMS: To evaluate the short, half and long term effects of treatment of addiction to alcohol or cocaine in the TC run by "Fundacion Salud y Comunidad" (Foundation Health and Community). DESIGN: descriptive pilot study, with a sequential design of cohort. 91 users completed a survey specifically designed to know their evolution at different follow-up periods (1, 3, 5 or 10 years after their exit from the TC): socio-demographic, psychoactive substance use, other variables related to the stay at the TC. Changes between before the TC and the present time regarding variables such as academic, labour, drug consumption, health, family and social adaptation and their criminal behaviour are described. RESULTS: the cohorts showed a relatively common previous socio-demographic pattern having received a similar treatment. The users reported to have diminished the frequent consumption of the main drug, having 48.9% never relapsed even through an occasional consumption of the drug/s. Also they perceived to have improved their health and family relations, as well as their aggressive behaviour and legal problems linked with their consumption of drug/s. CONCLUSIONS: after their rehabilitation in a TC, the users report a global decrease of the consumption of drugs and perceive an improvement of their health, family relations, violence and other problems linked to their former drug use.

Acute kidney failure in patients admitted due to COVID-19.

BACKGROUND AND AIM: In December 2019, a coronavirus 2019 (COVID-19) outbreak, caused by SARS-CoV-2, took place in Wuhan and was declared a global pandemic in March 2020 by the World Health Organization (WHO). It is a prominently respiratory infection, with potential cardiological, hematological, gastrointestinal and renal complications. Acute kidney injury (AKI) is found in 0.5%-25% of hospitalized COVID-19 patients and constitutes a negative prognostic factor. Renal damage mechanisms are not completely clear. We report the clinical evolution of hospitalized COVID-19 patients who presented with AKI requiring attention from the Nephrology team in a tertiary hospital in Madrid, Spain. METHODS: This is an observational prospective study including all COVID-19 cases that required hospitalization and Nephrology management from March 6th to May 12th. We collected clinical and analytical data of baseline characteristics, COVID-19 and AKI evolutions. RESULTS: We analyzed 41 patients with a mean age of 66.8 years (SD 2.1), 90.2% males, and with a history of chronic kidney disease (CKD) in 36.6%. 56.1% of patients presented with sever pneumonia or acute respiratory distress syndrome (ARDS), and 31.7% required intensive care. AKI etiology was prerenal in 61%, acute tubular necrosis in the context of sepsis in 24.4%, glomerular in 7.3% and tubular toxicity in 7.3% of the cases. We reported proteinuria in 88.9% and hematuria in 79.4% of patients. 48.8% of patients required renal replacement therapy (RRT). Median length of stay was 12 days (interquartilic range 9-23) and 22% of the population died. Patients who developed AKI during hospital stay presented with higher C-reactive protein, Lactate dehydrogenase-LDH and d-dimer values, more severe pulmonary damage, more frequent intensive care unit-ICU admission, treatment with lopinavir/ritonavir and biological drugs and RRT requirement. CONCLUSIONS: Hypovolemia and dehydration are a frequent cause of AKI among COVID-19 patients. Those who develop AKI during hospitalization display worse prognostic factors in terms of pulmonary damage, renal damage, and analytical findings. We believe that monitorization of renal markers as well as individualized fluid management can play a key role in AKI prevention.

Immunoinformatics and Pepscan strategies on the path of a peptide-based serological diagnosis of COVID19.

Several diagnostic tools have been developed for clinical and epidemiological assays. RT-PCR and antigen detection tests are more useful for diagnosis of acute disease, while antibody tests allow the estimation of exposure in the population. Currently, there is an urgent need for the development of diagnostic tests for COVID-19 that can be used for large-scale epidemiological sampling. Through a comprehensive strategy, potential 16 mer antigenic peptides suited for antibody-based SARS-CoV-2 diagnosis were identified. A systematic scan of the three structural proteins (S,N and M) and the non-structural proteins (ORFs) present in the SARS-CoV-2 virus was conducted through the combination of immunoinformatic methods, peptide SPOT synthesis and an immunoassay with cellulose-bound peptides (Pepscan). The Pepscan filter paper sheets with synthetic peptides were tested against pools of sera of COVID-19 patients. Antibody recognition showed a strong signal for peptides corresponding to the S, N and M proteins of SARS-CoV-2 virus, but not for the ORFs proteins. The peptides exhibiting higher signal intensity were found in the C-terminal region of the N protein. Several peptides of this region showed strong recognition with all three immunoglobulins in the pools of sera. The differential reactivity observed between the different immunoglobulin isotypes (IgA, IgM and IgG) within different regions of the S and N proteins, can be advantageous for ensuring accurate diagnosis of all infected patients, with different times of exposure to infection. Few peptides of the M protein showed antibody recognition and no recognition was observed for peptides of the ORFs proteins.

[Acute kidney failure in patients admitted due to COVID-19]. / Fracaso renal agudo en pacientes hospitalizados por COVID-19.

BACKGROUND AND AIM: In December 2019, a coronavirus 2019 (COVID-19) outbreak, caused by SARS-CoV-2, took place in Wuhan, China, and was declared a global pandemic in March 2020 by the World Health Organization. It is a prominently respiratory infection, with potential cardiological, hematological, gastrointestinal and renal complications. Acute kidney injury (AKI) is found in 0.5-25% of hospitalized COVID-19 patients and constitutes a negative prognostic factor. Renal damage mechanisms are not completely clear. We report the clinical evolution of hospitalized COVID-19 patients who presented with AKI requiring attention from the Nephrology team in a tertiary hospital in Madrid, Spain. METHODS: This is an observational prospective study including all COVID-19 cases that required hospitalization and Nephrology management from March 6th to May 12th 2020. We collected clinical and analytical data of baseline characteristics, COVID-19 and AKI evolutions. RESULTS: We analyzed 41 patients with a mean age of 66.8 years (SD 2.1), 90.2% males, and with a history of chronic kidney disease in 36.6%. A percentage of 56.1 presented with severe pneumonia or acute respiratory distress syndrome, and 31.7% required intensive care. AKI etiology was prerenal in 61%, acute tubular necrosis in the context of sepsis in 24.4%, glomerular in 7.3% and tubular toxicity in 7.3% of the cases. We reported proteinuria in 88.9% and hematuria in 79.4% of patients. A percentage of 48.8 required renal replacement therapy. Median length of stay was 12 days (IQR 9-23) and 22% of the population died. Patients who developed AKI during hospital stay presented with higher C-reactive protein, LDH and D-dimer values, more severe pulmonary damage, more frequent ICU admission, treatment with lopinavir/ritonavir and biological drugs and renal replacement therapy requirement. CONCLUSIONS: Hypovolemia and dehydration are a frequent cause of AKI among COVID-19 patients. Those who develop AKI during hospitalization display worse prognostic factors in terms of pulmonary damage, renal damage, and analytical findings. We believe that monitorization of renal markers, as well as individualized fluid management, can play a key role in AKI prevention.

Analysis of solitary pulmonary nodule after surgical resection in patients with 18F-FDG positron emission tomography integrated computed tomography in the preoperative work-up. / Análisis del nódulo pulmonar solitario tras su resección quirúrgica en pacientes con 18F-FDG PET-TC integrado en el estudio preoperatorio.

INTRODUCTION: To analyse clinicopathological characteristics of patients operated for pulmonary solitary nodule (PSN) and 18F-FDG integrated PET-CT scan after surgical resection. METHODOLOGY: Retrospective study on a prospective database of patients operated from January 2007 to October 2017 for PSN without preoperative diagnosis. Dependent variable was anatomopathological result (benign vs malignant) of PSN. Variables of the study were: age, sex, PET-CT uptake, SUVmax, smoking history, COPD, previous history of malignant disease, tumoral location, and tumour size on CT-scan. RESULTS: A total of 305 patients were included in this study, 225 (73.8%) men, 80 (26.2%) women, mean age = 63.9 (range 29-86 years), mean size PSN = 1.68 (s.d. .65 cm), benign = 46 (15.1%), malignant = 258 (84.6%), type of resection: pulmonary wedge = 151 (49.5%), lobectomy = 141 (46.2%), segmentectomy = 12 (3.9%), exploratory intervention = 1 (0.3%). Postoperative mortality was 1.9%. COPD = 50.8% cases, previous cancer disease = 172 cases (56.4%), smoking history = 250 cases (82.0%), positive PET = 280 cases (91.8%), PSN in upper pulmonary fields = 204 cases (66.9%), median SUVmax = 3.4 (range 0-20.7). Backward stepwise binary logistic regression model showed that age, SUVmax, previous malignant disease and female sex were independent risk factors with statistical significance (p < .05). Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 94.6%, 23.4%, 87.1%, 44.0%, and 83.6% respectively. There were 14 false negative cases (4.6%) and 36 false positive cases (11.8%). CONCLUSIONS: Age, SUVmax, previous malignant disease, and female sex were independent risk factors in our study. Each case should be individually evaluated in a multidisciplinary committee, and the patient's preferences or concerns should be kept in mind in decision-making. Surgical resection of PSN is not exempt from morbidity and mortality, even in sublobar or pulmonary wedge resection.

Defining chlorophyll-a reference conditions in European lakes.

The concept of "reference conditions" describes the benchmark against which current conditions are compared when assessing the status of water bodies. In this paper we focus on the establishment of reference conditions for European lakes according to a phytoplankton biomass indicator--the concentration of chlorophyll-a. A mostly spatial approach (selection of existing lakes with no or minor human impact) was used to set the reference conditions for chlorophyll-a values, supplemented by historical data, paleolimnological investigations and modelling. The work resulted in definition of reference conditions and the boundary between "high" and "good" status for 15 main lake types and five ecoregions of Europe: Alpine, Atlantic, Central/Baltic, Mediterranean, and Northern. Additionally, empirical models were developed for estimating site-specific reference chlorophyll-a concentrations from a set of potential predictor variables. The results were recently formulated into the EU legislation, marking the first attempt in international water policy to move from chemical quality standards to ecological quality targets.

Class A G Protein-Coupled Receptor Antagonist Famotidine as a Therapeutic Alternative Against SARS-CoV2: An In Silico Analysis.

The pandemic associated with Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV2) and its disease named COVID-19 challenged the scientific community to discover effective therapeutic solutions in a short period. Repurposing existing drugs is one viable approach that emphasizes speed during these urgent times. Famotidine, a class A G protein-coupled receptor antagonist used for the treatment of gastroesophageal reflux was recently identified in an in silico screening. Additionally, a recent retrospective clinical report showed that the treatment with famotidine provided a good outcome in patients infected with SARS-CoV2. A clinical trial testing effectiveness of famotidine in combination with hydroxychloroquine is currently ongoing in the United States (US). In the 1990s, famotidine was described as an antiviral agent against human immunodeficiency virus (HIV). Interestingly, some HIV protease inhibitors are presently being used against SARS-CoV2. However, it is not clear if famotidine could be effective against SARS-CoV2. Thus, by using a computational analysis, we aimed to examine if the antiviral effect of famotidine could be related to the inhibition of proteases involved in the virus replication. Our results showed that famotidine could interact within the catalytic site of the three proteases associated with SARS-CoV2 replication. However, weak binding affinity of famotidine to these proteases suggests that a successful famotidine therapy could likely be achieved only in combination with other antiviral drugs. Finally, analysis of famotidine's pharmacokinetic parameters indicated that its effect against SARS-CoV2 infection could be reached only upon intravenous administration. This work will contribute to the pharmacological knowledge of famotidine as an antiviral agent against SARS-CoV2.

Unrevealing sequence and structural features of novel coronavirus using in silico approaches: The main protease as molecular target.

Direct-acting antivirals are effective tools to control viral infections. SARS-CoV-2 is a coronavirus associated with the epidemiological outbreak in late 2019. Previous reports showed that HIV-1 protease inhibitors could block SARS-CoV main protease. Based on that and using an in silico approach, we evaluated SARS-CoV-2 main protease as a target for HIV-1 protease inhibitors to reveal the structural features related to their antiviral effect. Our results showed that several HIV inhibitors such as lopinavir, ritonavir, and saquinavir produce strong interaction with the active site of SARS-CoV-2 main protease. Furthermore, broad library protease inhibitors obtained from PubChem and ZINC (www.zinc.docking.org) were evaluated. Our analysis revealed 20 compounds that could be clustered into three groups based on their chemical features. Then, these structures could serve as leading compounds to develop a series of derivatives optimizing their activity against SARS-CoV-2 and other coronaviruses. Altogether, the results presented in this work contribute to gain a deep understanding of the molecular pharmacology of SARS-CoV-2 treatment and validate the use of protease inhibitors against SARS-CoV-2.

Role of changes in SARS-CoV-2 spike protein in the interaction with the human ACE2 receptor: An in silico analysis.

Many human viral diseases are a consequence of a zoonotic event. Some of the diseases caused by these zoonotic events have affected millions of people around the world, some of which have resulted in high rates of morbidity/mortality in humans. Changes in the viral proteins that function as ligands of the host receptor may promote the spillover between species. The most recent of these zoonotic events that have caused an ongoing epidemic of high magnitude is the Covid-19 epidemics caused by SARS-CoV-2. The aim of this study was to determine the mutation(s) in the sequence of the spike protein of the SARS-CoV-2 that might be favoring human to human transmission. An in silico approach was performed, and changes were detected in the S1 subunit of the receptor-binding domain of spike. The observed changes have significant effect on SARS-CoV-2 spike/ACE2 interaction and produce a reduction in the binding energy, compared to the one of the Bat-CoV to this receptor. The data presented in this study suggest a higher affinity of the SARS-Cov-2 spike protein to the human ACE2 receptor, compared to the one of Bat-CoV spike and ACE2. This could be the cause of the rapid viral spread of SARS-CoV-2 in humans.

In silico modeling and structural analysis of asparaginyl endopeptidase of schistosoma mansoni (Sm32): Immunological and drug target implications.

Asparaginyl endopeptidase (AE) of Schistosoma mansoni (Sm32), also known as legumain, is a cysteine protease indirectly involved in the digestion of hemoglobin of Schistosoma sp. in the gastrodermis, being a vaccine candidate against this trematode and a potential drug target. This study presents a model for the three-dimensional structure of Sm32 determined by means of homology modeling and a molecular dynamics simulation with explicit solvent refinement. The structure proved to be consistent with other AEs of known crystal structures described in their proenzyme form, revealing a catalytic domain that has a caspase-like overall structure and a C-terminal prodomain that adopts a death-domain-like architecture. We identified amino acid mutations in the ßIV strand, differences in the active site and in the surface electrostatic potentials between Sm32 and its homologous proteins of mouse and human. Additionally, amino acid changes in the activation peptide (AP) of the S. mansoni protein were determined. Our results strongly suggest that Sm32 can be exploited as a potential target for drug design and for the development of biomarkers used in diagnosis and in novel vaccines for the control of parasitic infection, opening the perspective of medicinal chemistry developments.

Antiviral activity of flavonoids present in aerial parts of Marcetia taxifolia against Hepatitis B virus, Poliovirus, and Herpes Simplex Virus in vitro.

Marcetia taxifolia is a neotropical plant present in South America and it has been evaluated in several biological models due to the presence of active metabolites. Nevertheless, there is a limited quantity of studies related to the antiviral activity of the compounds present in this genus. In our work, the antiviral effect of the compounds isolated from the aerial parts of Marcetia taxifolia was evaluated against Hepatitis B virus (HBV), Herpes Simplex Virus type 1 (HSV-1), and Poliovirus type 1 (PV-1). The cytopathic effect and viral quantification by qPCR were determined as indicative of antiviral activity. Our data show that myricetin rhamnoside (MyrG), myricetin-3-α-O-ramnosil (1→6)-α-galactoside (MyrGG), 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone (PMF), 5-hydroxy-3,6,7,3',4'pentamethoxyflavone (PMF-OH) had antiviral activity without cytotoxic effects. The methoxyflavones PMF and PMF-OH were the most active compounds, showing an antiviral effect against all the evaluated viruses. Computational studies showed that these compounds could interact with the Reverse Transcriptase. Altogether, these results suggest that the flavonoids (related to myricetin and methoxyflavones) are the main antiviral compounds present in the aerial parts of Marcetia taxifolia. Furthermore, our results showed that the methoxyflavones have a broad antiviral activity, which represents an opportunity to evaluate these flavonoids as lead molecules to develop new antiviral compounds.

Comparative analyses of the ß-tubulin gene and molecular modeling reveal molecular insight into the colchicine resistance in kinetoplastids organisms.

Differential susceptibility to microtubule agents has been demonstrated between mammalian cells and kinetoplastid organisms such as Leishmania spp. and Trypanosoma spp. The aims of this study were to identify and characterize the architecture of the putative colchicine binding site of Leishmania spp. and investigate the molecular basis of colchicine resistance. We cloned and sequenced the ß-tubulin gene of Leishmania (Viannia) guyanensis and established the theoretical 3D model of the protein, using the crystallographic structure of the bovine protein as template. We identified mutations on the Leishmania ß-tubulin gene sequences on regions related to the putative colchicine-binding pocket, which generate amino acid substitutions and changes in the topology of this region, blocking the access of colchicine. The same mutations were found in the ß-tubulin sequence of kinetoplastid organisms such as Trypanosoma cruzi, T. brucei, and T. evansi. Using molecular modelling approaches, we demonstrated that conformational changes include an elongation and torsion of an α-helix structure and displacement to the inside of the pocket of one ß-sheet that hinders access of colchicine. We propose that kinetoplastid organisms show resistance to colchicine due to amino acids substitutions that generate structural changes in the putative colchicine-binding domain, which prevent colchicine access.

The problematic internet entertainment use scale for adolescents: prevalence of problem internet use in Spanish high school students.

Many researchers and professionals have reported nonsubstance addiction to online entertainments in adolescents. However, very few scales have been designed to assess problem Internet use in this population, in spite of their high exposure and obvious vulnerability. The aim of this study was to review the currently available scales for assessing problematic Internet use and to validate a new scale of this kind for use, specifically in this age group, the Problematic Internet Entertainment Use Scale for Adolescents. The research was carried out in Spain in a gender-balanced sample of 1131 high school students aged between 12 and 18 years. Psychometric analyses showed the scale to be unidimensional, with excellent internal consistency (Cronbach's alpha of 0.92), good construct validity, and positive associations with alternative measures of maladaptive Internet use. This self-administered scale can rapidly measure the presence of symptoms of behavioral addiction to online videogames and social networking sites, as well as their degree of severity. The results estimate the prevalence of this problematic behavior in Spanish adolescents to be around 5 percent.

The 6-phosphogluconate dehydrogenase of Leishmania (Leishmania) mexicana: gene characterization and protein structure prediction.

6-Phosphogluconate dehydrogenase (6PGDH) is a key enzyme of the oxidative branch involved in the generation of NADPH and ribulose 5-phosphate. In the present work, we describe the cloning, sequencing and characterization of a 6PGDH gene from Leishmania (Leishmania) mexicana. The gene encodes a polypeptide chain of 479 amino acid residues with a predicted molecular mass of 52 kDa and a pI of 5.77. The recombinant protein possesses a dimeric quaternary structure and displays kinetic parameter values intermediate between those reported for Trypanosoma brucei and T. cruzi with apparent K(m) values of 6.93 and 5.2 µM for 6PG and NADP(+), respectively. The three-dimensional structure of the enzymes of Leishmania and T. cruzi were modelled from their amino acid sequence using the crystal structure of the enzyme of T. brucei as template. The amino acid residues located in the 6PGDH C-terminal region, which are known to participate in the salt bridges maintaining the protein dimeric structure, differed significantly among the enzymes of Leishmania, T. cruzi, and T. brucei. Our results strongly suggest that 6PGDH can be selected as a potential target for the development of new therapeutic drugs in order to improve existing chemotherapeutic treatments against these parasites.