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1.
Nucleic Acids Res ; 50(19): 11199-11213, 2022 10 28.
Artículo en Inglés | MEDLINE | ID: mdl-36271789

RESUMEN

Standalone ring nucleases are CRISPR ancillary proteins, which downregulate the immune response of Type III CRISPR-Cas systems by cleaving cyclic oligoadenylates (cA) second messengers. Two genes with this function have been found within the Sulfolobus islandicus (Sis) genome. They code for a long polypeptide composed by a CARF domain fused to an HTH domain and a short polypeptide constituted by a CARF domain with a 40 residue C-terminal insertion. Here, we determine the structure of the apo and substrate bound states of the Sis0455 enzyme, revealing an insertion at the C-terminal region of the CARF domain, which plays a key role closing the catalytic site upon substrate binding. Our analysis reveals the key residues of Sis0455 during cleavage and the coupling of the active site closing with their positioning to proceed with cA4 phosphodiester hydrolysis. A time course comparison of cA4 cleavage between the short, Sis0455, and long ring nucleases, Sis0811, shows the slower cleavage kinetics of the former, suggesting that the combination of these two types of enzymes with the same function in a genome could be an evolutionary strategy to regulate the levels of the second messenger in different infection scenarios.


Asunto(s)
Proteínas Asociadas a CRISPR , Proteínas Asociadas a CRISPR/metabolismo , Sistemas CRISPR-Cas , Oligorribonucleótidos/química , Nucleótidos de Adenina/metabolismo , Endonucleasas/metabolismo
2.
Int J Mol Sci ; 25(9)2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38732145

RESUMEN

Bacteria and their phage adversaries are engaged in an ongoing arms race, resulting in the development of a broad antiphage arsenal and corresponding viral countermeasures. In recent years, the identification and utilization of CRISPR-Cas systems have driven a renewed interest in discovering and characterizing antiphage mechanisms, revealing a richer diversity than initially anticipated. Currently, these defense systems can be categorized based on the bacteria's strategy associated with the infection cycle stage. Thus, bacterial defense systems can degrade the invading genetic material, trigger an abortive infection, or inhibit genome replication. Understanding the molecular mechanisms of processes related to bacterial immunity has significant implications for phage-based therapies and the development of new biotechnological tools. This review aims to comprehensively cover these processes, with a focus on the most recent discoveries.


Asunto(s)
Bacterias , Bacteriófagos , Sistemas CRISPR-Cas , Bacterias/genética , Bacteriófagos/fisiología , Bacteriófagos/genética , Farmacorresistencia Bacteriana/genética , Humanos , Infecciones Bacterianas/inmunología , Infecciones Bacterianas/microbiología
3.
Qual Life Res ; 32(8): 2361-2373, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37010804

RESUMEN

PURPOSE: To estimate the health-related quality of life (HRQOL) according to glycemic status, and its relationship with sociodemographic and clinical factors in a population at risk of developing type 2 diabetes (T2D). METHODS: Cross-sectional study, using cluster sampling. Data were collected from 1135 participants over 30 years of age, at risk of developing T2D from the PREDICOL project. Participants' glycemic status was defined using an oral glucose tolerance test (OGTT). Participants were divided into normoglycemic subjects (NGT), prediabetes and diabetics do not know they have diabetes (UT2D). HRQOL was assessed using the EQ-5D-3L questionnaire of the EuroQol group. Logistic regression and Tobit models were used to examine factors associated with EQ-5D scores for each glycemic group. RESULTS: The mean age of participants was 55.6 ± 12.1 years, 76.4% were female, and one in four participants had prediabetes or unknown diabetes. Participants reported problems most frequently on the dimensions of Pain/Discomfort and Anxiety/Depression in the different glycemic groups. The mean EQ-5D score in NGT was 0.80 (95% CI 0.79-0.81), in prediabetes, 0.81 (95% CI 0.79-0.83), and in participants with UT2D of 0.79 (95% CI 0.76-0.82), respectively. Female sex, older age, city of residence, lower education, receiving treatment for hypertension, and marital status were significantly associated with lower levels of HRQOL in the Tobit regression analysis. CONCLUSIONS: HRQOL of NGT, prediabetes, and UT2D participants was statistically similar. However, factors such as gender, age. and place of residence were found to be significant predictors of HRQOL for each glycemic group.


Asunto(s)
Diabetes Mellitus Tipo 2 , Estado Prediabético , Humanos , Femenino , Adulto , Persona de Mediana Edad , Anciano , Masculino , Calidad de Vida/psicología , Diabetes Mellitus Tipo 2/epidemiología , Ciudades , Estado Prediabético/epidemiología , Estudios Transversales , América Latina , Encuestas y Cuestionarios , Factores de Riesgo , Estado de Salud
4.
Nucleic Acids Res ; 49(21): 12577-12590, 2021 12 02.
Artículo en Inglés | MEDLINE | ID: mdl-34850143

RESUMEN

Type III CRISPR-Cas effector systems detect foreign RNA triggering DNA and RNA cleavage and synthesizing cyclic oligoadenylate molecules (cA) in their Cas10 subunit. cAs act as a second messenger activating auxiliary nucleases, leading to an indiscriminate RNA degradation that can end in cell dormancy or death. Standalone ring nucleases are CRISPR ancillary proteins which downregulate the strong immune response of Type III systems by degrading cA. These enzymes contain a CRISPR-associated Rossman-fold (CARF) domain, which binds and cleaves the cA molecule. Here, we present the structures of the standalone ring nuclease from Sulfolobus islandicus (Sis) 0811 in its apo and post-catalytic states. This enzyme is composed by a N-terminal CARF and a C-terminal wHTH domain. Sis0811 presents a phosphodiester hydrolysis metal-independent mechanism, which cleaves cA4 rings to generate linear adenylate species, thus reducing the levels of the second messenger and switching off the cell antiviral state. The structural and biochemical analysis revealed the coupling of a cork-screw conformational change with the positioning of key catalytic residues to proceed with cA4 phosphodiester hydrolysis in a non-concerted manner.


Asunto(s)
Nucleótidos de Adenina/metabolismo , Proteínas Asociadas a CRISPR/metabolismo , Sistemas CRISPR-Cas , Endonucleasas/metabolismo , Nucleótidos Cíclicos/metabolismo , Oligorribonucleótidos/metabolismo , Sulfolobus solfataricus/enzimología , Nucleótidos de Adenina/química , Sitios de Unión/genética , Biocatálisis , Proteínas Asociadas a CRISPR/química , Proteínas Asociadas a CRISPR/genética , Cromatografía Liquida , Cristalografía por Rayos X , Endonucleasas/química , Endonucleasas/genética , Cinética , Espectrometría de Masas/métodos , Modelos Moleculares , Mutación , Nucleótidos Cíclicos/química , Oligorribonucleótidos/química , Dominios Proteicos , Sulfolobus solfataricus/genética
5.
Subcell Biochem ; 99: 285-315, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36151380

RESUMEN

The essential membrane complex FtsE/FtsX (FtsEX), belonging to the ABC transporter superfamily and widespread among bacteria, plays a relevant function in some crucial cell wall remodeling processes such as cell division, elongation, or sporulation. FtsEX plays a double role by recruiting proteins to the divisome apparatus and by regulating lytic activity of the cell wall hydrolases required for daughter cell separation. Interestingly, FtsEX does not act as a transporter but uses the ATPase activity of FtsE to mechanically transmit a signal from the cytosol, through the membrane, to the periplasm that activates the attached hydrolases. While the complete molecular details of such mechanism are not yet known, evidence has been recently reported that clarify essential aspects of this complex system. In this chapter we will present recent structural advances on this topic. The three-dimensional structure of FtsE, FtsX, and some of the lytic enzymes or their cognate regulators revealed an unexpected scenario in which a delicate set of intermolecular interactions, conserved among different bacterial genera, could be at the core of this regulatory mechanism providing exquisite control in both space and time of this central process to assist bacterial survival.


Asunto(s)
Proteínas Bacterianas , Proteínas de Escherichia coli , Transportadoras de Casetes de Unión a ATP/química , Transportadoras de Casetes de Unión a ATP/metabolismo , Adenosina Trifosfatasas/metabolismo , Bacterias/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Escherichia coli/metabolismo , Unión Proteica
6.
Aging Clin Exp Res ; 35(3): 591-598, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36626043

RESUMEN

BACKGROUND: Alterations in resting metabolic rate (RMR), the largest component of daily total energy expenditure, with aging have been shown in various studies. However, little is known about the associations between RMR and health outcomes in later life. AIMS: To analyze whether RMR is associated with incident disability and mobility decline in a 10-year longitudinal study, as well as the moderating role of frailty in these associations. METHODS: Data from 298 older adults aged 70 and over from the Frailty and Dependence in Albacete (FRADEA) study in Spain were used, including a baseline measurement in 2007-2009 and a follow-up measurement 10 years later. RMR was measured by indirect calorimetry. Outcomes were incident disability in basic activities of daily living (BADL, Barthel Index), incident disability in instrumental ADL (IADL, Lawton index), and mobility decline (Functional Ambulation Categories scores). Fried's frailty phenotype was used as an indicator of frailty. Logistic regression analyses were conducted. RESULTS: Fully adjusted and stratified analyses revealed that only in the pre-frail/frail group, a higher RMR was associated with a lower risk of incident BADL disability (OR = 0.47, 95% CI = 0.23-0.96, p = 0.037), incident IADL disability (OR = 0.39, 95% CI = 0.18-0.84, p = 0.017), and mobility decline (OR = 0.30, 95% CI = 0.14-0.64, p = 0.002). CONCLUSIONS: To our knowledge, this is the first study looking at the associations between RMR and functional health using a longitudinal research design. The results suggest that RMR could be used as an early identifier of a specific resilient group within the pre-frail and frail older population, with a lower risk of further health decline.


Asunto(s)
Fragilidad , Humanos , Anciano , Fragilidad/epidemiología , Estudios Longitudinales , Estudios de Cohortes , Anciano Frágil , Metabolismo Basal , Actividades Cotidianas
7.
Am J Geriatr Psychiatry ; 30(4): 431-443, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35123862

RESUMEN

OBJECTIVE: To analyze the psychological and functional sequelae of the COVID-19 pandemic among older adults living in long term care facilities (LTCFs). DESIGN: Cohort longitudinal study SETTING ANT PARTICIPANTS: A total of 215 residents ≥ 65 years without moderate-to-severe cognitive impairment, living in five LTCFs in Albacete (Spain). MEASUREMENTS: Baseline on-site data were collected between March - June 2020 and three-month follow-up between June to September 2020. Symptoms of depression, anxiety, posttraumatic stress disorder (PTSD), and sleep disturbances were measured as psychological variables. Disability in basic activities of daily living (BADL), ambulation and frailty were assessed as functional variables. Differences were analyzed in relation to level of comorbidity and test positivity for COVID-19. RESULTS: At baseline, residents with COVID-19 presented worse functionality, higher frailty levels and malnutrition risk compared to non-COVID-19 residents. At three-month follow-up, higher rates of clinically significant depressive symptoms (57.7%), anxiety symptoms (29.3%), PTSD symptoms (19.1%) and sleep disturbances (93.0%) were found among residents regardless of COVID status. Thus, among 215 residents, 101 (47%) experienced a decline in BADL from baseline to the 3-month follow-up (median functional loss = 5 points in Barthel Index). In multivariate analyses, COVID-19 status did not explain either the functional or the ambulation loss. By contrast, residents with low comorbidity and COVID-19 presented higher PTSD symptoms (effect 2.58; 95% CI 0.93 to 4.23) and anxiety symptoms (effect 2.10; 95% CI 0.48 to 3.73) compared to the low comorbidity/non-COVID19 group. CONCLUSION: COVID-19 pandemic was associated, after three-months, with high psychological impact in older adults in LTCFs., specifically with higher post-traumatic stress and anxiety symptoms. Functional decline did not differ in relation to COVID-19 status but could be related to isolation strategies used for pandemic control.


Asunto(s)
COVID-19 , Trastornos por Estrés Postraumático , Actividades Cotidianas , Anciano , Ansiedad/epidemiología , COVID-19/epidemiología , Depresión/epidemiología , Humanos , Cuidados a Largo Plazo , Estudios Longitudinales , Pandemias , Trastornos por Estrés Postraumático/epidemiología
8.
Can J Physiol Pharmacol ; 100(4): 295-305, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34757855

RESUMEN

The current study aimed to determine the antidiabetic and antidyslipidemic activities of moronic acid methyl ester (1) (compound 1) by in vivo, in vitro, in silico, and molecular biology studies. Compound 1 was evaluated to establish its dose-dependent antidiabetic and antihyperglycemic (50 mg/kg) activities, in diabetic and normoglycemic male CD1 mice, respectively. Also, compound 1 was subjected to a subacute study (50 mg/kg per day for 8 days) to determine blood biochemical profiles and the expression of protein tyrosine phosphatase 1B (PTP-1B), glucose transporter type 4 (GLUT4), peroxisome proliferator-activated receptor α (PPAR-α), PPAR-γ, adiponectin, interleukin-1ß (IL-1ß), and monocyte chemoattractant protein 1 (MCP-1) in adipose tissue of animals after treatment. Different doses in acute administration of compound 1 decreased glycemia (p < 0.05) compared with vehicle, showing greater effectiveness in the range 50-160 mg/kg. Also, the oral glucose tolerance test showed that compound 1 induced a significant antihyperglycemic action by opposing the hyperglycemic peak (p < 0.05). Moreover, compound 1 subacute administration decreased glucose and triglyceride levels after treatment (p < 0.05); while the expression of PPAR-α and PPAR-γ, adiponectin, and GLUT4 displayed an increase (p < 0.05) compared with the diabetic control group. In conclusion, compound 1 showed antihyperglycemic, antidiabetic, and antidyslipidemic effects in normal and diabetic mice, probably due to insulin sensitization through increased mRNA expression of GLUT4, PPAR-α, PPAR-γ, and adiponectin genes.


Asunto(s)
Diabetes Mellitus Experimental , PPAR alfa , Adiponectina/metabolismo , Animales , Glucemia/metabolismo , Diabetes Mellitus Experimental/metabolismo , Ésteres/uso terapéutico , Glucosa , Transportador de Glucosa de Tipo 4/genética , Hipoglucemiantes/química , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Masculino , Ratones , Ácido Oleanólico/análogos & derivados , PPAR alfa/metabolismo , PPAR gamma/metabolismo , Triglicéridos
9.
Rev Panam Salud Publica ; 46: e105, 2022.
Artículo en Español | MEDLINE | ID: mdl-36060202

RESUMEN

Objective: Reconstruct the experience of the Virtual Campus for Public Health (VCPH) from 2012 to 2019 in Colombia. Methods: The experience of public health training through the VCPH in Colombia in the period 2012-2019 was systematized. The information is presented in cross-section time series to show the evolution of the VCPH in Colombia over time. Results: A total of 2 627 health professionals took tutored courses and 34 012 followed self-learning courses on relevant, up-to-date, priority public health issues. An important aspect was the opportunity to access remote regions through VCPH training processes that were cost-free for end users. The experience highlights the relevance of the VCPH in reducing the gap in updated human talent in the health field through virtual education with diversity in its modalities and content. Conclusions: Reconstruction of the experience in Colombia showed how the VCPH evolved and strengthened to offer quality training processes that respond to the country's problems and needs. Collaborative work between universities and the Pan American Health Organization resulted in consolidation of the VCPH.


Objetivo: Reconstruir a experiência do Campus Virtual de Saúde Pública (CVSP) de 2012 a 2019 na Colômbia. Métodos: Realizou-se a sistematização da experiência do processo de formação em saúde pública na Colômbia por meio do Campus, referente ao período de 2012 a 2019. As informações são apresentadas em séries transversais de períodos de tempo para mostrar a evolução histórica do CVSP na Colômbia. Resultados: Foram capacitados 2.627 profissionais de saúde em cursos com instrutor e 34.012 em cursos de autoaprendizagem sobre temas relevantes, atuais e prioritários de saúde pública. Destacam-se a oportunidade e o acesso a regiões remotas que o Campus obteve, por meio de processos de formação sem custo para o usuário final. A experiência destaca a relevância do Campus na redução da lacuna de atualização do talento humano da área da saúde, mediante processos de educação virtual com diversidade nas modalidades e ofertas de formação. Conclusões: A reconstrução da experiência da Colômbia mostrou a evolução e o fortalecimento do CVSP para oferecer processos de formação com qualidade, a fim de responder aos problemas e necessidades do país. A consolidação do Campus deve-se ao trabalho colaborativo entre as universidades e a Organização Pan-Americana da Saúde.

10.
Int J Mol Sci ; 23(11)2022 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-35682798

RESUMEN

Energetic carbon ions are promising projectiles used for cancer radiotherapy. A thorough knowledge of how the energy of these ions is deposited in biological media (mainly composed of liquid water) is required. This can be attained by means of detailed computer simulations, both macroscopically (relevant for appropriately delivering the dose) and at the nanoscale (important for determining the inflicted radiobiological damage). The energy lost per unit path length (i.e., the so-called stopping power) of carbon ions is here theoretically calculated within the dielectric formalism from the excitation spectrum of liquid water obtained from two complementary approaches (one relying on an optical-data model and the other exclusively on ab initio calculations). In addition, the energy carried at the nanometre scale by the generated secondary electrons around the ion's path is simulated by means of a detailed Monte Carlo code. For this purpose, we use the ion and electron cross sections calculated by means of state-of-the art approaches suited to take into account the condensed-phase nature of the liquid water target. As a result of these simulations, the radial dose around the ion's path is obtained, as well as the distributions of clustered events in nanometric volumes similar to the dimensions of DNA convolutions, contributing to the biological damage for carbon ions in a wide energy range, covering from the plateau to the maximum of the Bragg peak.


Asunto(s)
Carbono , Agua , Iones , Método de Montecarlo , Fenómenos Físicos
11.
Int J Mol Sci ; 23(11)2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35682723

RESUMEN

Angiotensin II (Ang II) is a critical regulator of insulin signaling in the cardiovascular system and metabolic tissues. However, in adipose cells, the regulatory role of Ang II on insulin actions remains to be elucidated. The effect of Ang II on insulin-induced insulin receptor (IR) phosphorylation, Akt activation, and glucose uptake was examined in 3T3-L1 adipocytes. In these cells, Ang II specifically inhibited insulin-stimulated IR and insulin receptor substrate-1 (IRS-1) tyrosine-phosphorylation, Akt activation, and glucose uptake in a time-dependent manner. These inhibitory actions were associated with increased phosphorylation of the IR at serine residues. Interestingly, Ang II-induced serine-phosphorylation of IRS was not detected, suggesting that Ang II-induced desensitization begins from IR regulation itself. PKC inhibition by BIM I restored the inhibitory effect of Ang II on insulin actions. We also found that Ang II promoted activation of several PKC isoforms, including PKCα/ßI/ßII/δ, and its association with the IR, particularly PKCßII, showed the highest interaction. Finally, we also found a similar regulatory effect of Ang II in isolated adipocytes, where insulin-induced Akt phosphorylation was inhibited by Ang II, an effect that was prevented by PKC inhibitors. These results suggest that Ang II may lead to insulin resistance through PKC activation in adipocytes.


Asunto(s)
Angiotensina II , Receptor de Insulina , Adipocitos/metabolismo , Angiotensina II/metabolismo , Angiotensina II/farmacología , Glucosa/metabolismo , Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptor de Insulina/metabolismo , Serina/metabolismo
12.
Geriatr Nurs ; 46: 184-190, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35728301

RESUMEN

OBJECTIVES: To determine whether the interaction between frailty status and depression risk is associated with hospitalization density in older adults. METHODS: Ongoing cohort study in 794 subjects aged over 70 years from Albacete (Spain). Data were collected on depression risk, frailty, hospitalizations, and covariates. Participants were categorized into six groups. RESULTS: Adjusted hospitalization risk was higher for groups of prefrail/-non depression risk (HR 1.48; 95% confidence interval (CI) 1.16-1.89), prefrail/depression risk (HR 1.73; 95% CI 1.29-2.30), frail/non depression risk (HR 1.79; 95% CI 1.22-2.62), and frail/depression risk (HR 2.12; 95% CI 1.49-3.02), compared with robust/non depression risk group (p<0.01). Frail and prefrail groups presented increased hospitalization density in the first four follow-up years. CONCLUSIONS: Depression risk changes the yearly probabilities of hospitalization in prefrail and frail groups, increasing them in the first years. Depression risk should be monitored in prefrail and frail older adults as an independent risk factor for hospitalization.


Asunto(s)
Fragilidad , Anciano , Estudios de Cohortes , Anciano Frágil , Evaluación Geriátrica , Hospitalización , Humanos , España/epidemiología
13.
Eur J Clin Invest ; 51(7): e13523, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33594702

RESUMEN

BACKGROUND: Due to insufficient scientific evidence, panels of tumour markers (TMs) are currently not recommended for use in suspected cancer. However, recent well-designed studies have revealed a potential clinical value in lung cancer. We analysed the diagnostic accuracy of a panel of 11 circulating TMs with clinically controlled thresholds in the differentiation of cancer from nonmalignant diseases. METHODS: We prospectively recruited 4776 consecutive patients presenting with focal or nonspecific symptoms suggestive of cancer who underwent testing for 11 serum TMs before diagnosis was known. The study abided by 2015 STARD guidelines. Tumour markers included, among others, carbohydrate antigen 19-9, carcinoembryonic antigen, alpha-fetoprotein, squamous cell carcinoma-associated antigen, prostate-specific antigen (males), neuron-specific enolase, progastrin-releasing peptide and carbohydrate antigen 125. Thresholds were adjusted for the presence of kidney failure, liver disease, effusions and dermatological disorders. Results showing ≥1 TMs with concentrations above threshold were considered positive. RESULTS: Benign diseases were diagnosed in 3281 (68.7%) patients and cancer in 1495 (31.3%), with epithelial cancers in 1214 (77% at stage IV). When applying criteria for controlled thresholds, overall specificity was 98%. Overall sensitivity of the panel in epithelial cancers was 72.2%, positive predictive value 93% and negative predictive value 90.5%. The area under the receiver operating characteristic curve was 0.920 (95% confidence interval, 0.902-0.924). CONCLUSIONS: By using clinically controlled cut-offs, the combined panel demonstrated an excellent ability to discriminate epithelial cancers from nonmalignant diseases. However, its use in clinical practice would need formal validation through a multicentre controlled trial assessing a panel-guided strategy vs. standard diagnosis.


Asunto(s)
Biomarcadores de Tumor/sangre , Neoplasias/sangre , Dolor Abdominal/fisiopatología , Anciano , Antígenos de Neoplasias/sangre , Antígeno Ca-125/sangre , Antígeno CA-19-9/sangre , Antígeno Carcinoembrionario/sangre , Carcinoma/sangre , Carcinoma/diagnóstico , Estudios de Casos y Controles , Disnea/fisiopatología , Femenino , Neoplasias Hematológicas/sangre , Neoplasias Hematológicas/diagnóstico , Humanos , Queratina-19/sangre , Linfadenopatía/fisiopatología , Linfoma/sangre , Linfoma/diagnóstico , Masculino , Melanoma/sangre , Melanoma/diagnóstico , Persona de Mediana Edad , Mucina-1/sangre , Neoplasias/diagnóstico , Neoplasias/fisiopatología , Enfermedades del Sistema Nervioso/fisiopatología , Dolor/fisiopatología , Fragmentos de Péptidos/sangre , Fosfopiruvato Hidratasa/sangre , Antígeno Prostático Específico/sangre , Proteínas Recombinantes/sangre , Sarcoma/sangre , Sarcoma/diagnóstico , Sensibilidad y Especificidad , Serpinas/sangre , Pérdida de Peso , alfa-Fetoproteínas/metabolismo
14.
Phys Chem Chem Phys ; 23(9): 5079-5095, 2021 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-33565529

RESUMEN

Electronic excitations and ionisations produced by electron impact are key processes in the radiation-induced damage mechanisms in materials of biological relevance, underlying important medical and technological applications, including radiotherapy, radiation protection in manned space missions and nanodevice fabrication techniques. However, experimentally measuring all the necessary electronic interaction cross-sections for every relevant material is an arduous task, so it is necessary having predictive models, sufficiently accurate yet easily implementable. In this work we present a model, based on the dielectric formalism, to provide reliable ionisation and excitation cross-sections for electron-impact on complex biomolecular media, considering their condensed-phase nature. We account for the indistinguishability and exchange between the primary beam and excited electrons, for the molecular electronic structure effects in the electron binding, as well as for low-energy corrections to the first Born approximation. The resulting approach yields total ionisation cross-sections, energy distributions of secondary electrons, and total electronic excitation cross-sections for condensed-phase biomaterials, once the electronic excitation spectrum is known, either from experiments or from a predictive model. The results of this methodology are compared with the available experimental data in water and DNA/RNA molecular building blocks, showing a very good agreement and a great predictive power in a wide range of electron incident energies, from the large values characteristic of electron beams down to excitation threshold. The proposed model constitutes a very useful procedure for computing the electronic interaction cross-sections for arbitrary biological materials in a wide range of electron incident energies.


Asunto(s)
Materiales Biocompatibles/química , Simulación por Computador , ADN/química , Electrones , Iones , Modelos Moleculares , Conformación Molecular , Transición de Fase , ARN/química , Termodinámica , Agua/química
15.
Phys Chem Chem Phys ; 23(35): 19173-19187, 2021 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-34357365

RESUMEN

Nanomaterials made of cerium oxides CeO2 and Ce2O3 have a broad range of applications, from catalysts in automotive, industrial or energy operations to promising materials to enhance hadrontherapy effectiveness in oncological treatments. To elucidate the physico-chemical mechanisms involved in these processes, it is of paramount importance to know the electronic excitation spectra of these oxides, which are obtained here through high-accuracy linear-response time-dependent density functional theory calculations. In particular, the macroscopic dielectric response functions  of both bulk CeO2 and Ce2O3 are derived, which compare remarkably well with the available experimental data. These results stress the importance of appropriately accounting for local field effects to model the dielectric function of metal oxides. Furthermore, we reckon the energy loss functions Im(-1/) of the materials, including the accurate evaluation of the momentum transfer dispersion from first-principles calculations. In this respect, by using Mermin-type parametrization we are able to model the contribution of different electronic excitations to the dielectric loss function. Finally, from the knowledge of the electron inelastic mean free path, together with the elastic mean free path provided by the relativistic Mott theory, we carry out statistical Monte Carlo (MC) electron transport simulations to reproduce the major features of the reported experimental reflection electron energy loss (REEL) spectra of cerium oxides. The good agreement with REEL experimental data strongly supports our approach based on MC modelling, whose main inputs were obtained using ab initio calculated electronic excitation spectra in a broad range of momentum and energy transfers.

16.
Vet Ophthalmol ; 24(2): 169-176, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33400365

RESUMEN

OBJECTIVE: To evaluate the safety and efficacy of unilateral topical application of rocuronium bromide in scops owls. ANIMALS STUDIED: Ten healthy adult scops owls. PROCEDURES: Birds weighting between 82-111 g were enrolled. Complete physical and ophthalmic examinations were performed. Each animal received a single dose of 0.15 mg of rocuronium bromide (30 µL) in a randomly selected eye. Static pupillometric evaluations were performed before and after drug instillation at 0, 30, 60, 90, and 120 minutes, in a room with fixed light intensity. Physical and ophthalmic examinations were carried out to evaluate possible adverse effects. RESULTS: Median pupil (95% CI) size at t0 was 7.10 mm (5.51-7.41) for placebo eyes and 7.22 mm (6.93-7.48) for treated eyes, showing no statistical differences (P > .05). When compared to the placebo eye, significant mydriasis was achieved at t30 [8.18 mm (7.22-9.00)] (P = .014) and lasting until t90 [7.35 mm (6.20-9.52)] (P = .004). Maximal mydriasis was obtained at t60 [8.63 mm (7.72-9.81)] (P = .001). During this period, the treated eye no longer responded to direct light stimulation. Complete mydriasis was observed in 5/10 birds (mean weight 97.4 g). Pupil size at t90 and t120 did not differ from baseline (P > .05) in treated eyes. No adverse effects were seen during the study period. CONCLUSION: Single-dose topical rocuronium bromide (0.15 mg) is a safe and effective medium duration mydriatic agent in scops owls. Further studies are needed to evaluate bilateral topical application and standardize the mydriatic protocol.


Asunto(s)
Midriáticos/farmacología , Rocuronio/farmacología , Estrigiformes , Administración Tópica , Animales , Fondo de Ojo , Midriáticos/efectos adversos , Pupila/efectos de los fármacos , Rocuronio/efectos adversos
17.
Tumour Biol ; 42(9): 1010428320958603, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32964798

RESUMEN

This study aimed to investigate whether changes in progastrin-releasing peptide (ProGRP) levels correlate with treatment response and can be used to optimize clinical management of patients with small-cell lung cancer. Patients with small-cell lung cancer (any stage) receiving chemotherapy were eligible. ProGRP was measured in serum/plasma at baseline and after each chemotherapy cycle using the Elecsys® ProGRP assay (Roche Diagnostics). Treatment response was assessed by computed tomography scan. The primary objective was to examine whether changes in ProGRP levels correlated with computed tomography scan results after two cycles of chemotherapy. The prognostic value of ProGRP among patients receiving first-line chemotherapy was also assessed. Overall, 261 patients from six centers were eligible. Among patients with elevated baseline ProGRP (>100 pg/mL), a ProGRP decline after Cycle 2 was associated with nonprogression (area under the curve: 84%; 95% confidence interval: 72.8-95.1; n = 141). ProGRP changes from baseline to end of Cycle 1 were predictive of response, as determined by computed tomography scan 3 weeks later (area under the curve: 87%; 95% confidence interval: 74.1-99.2; n = 137). This was enhanced by repeat measurements, with a 92% area under the curve (95% confidence interval: 85.3-97.8) among patients with ProGRP data after both Cycles 1 and 2 (n = 123); if a patient experienced a ≥25% decline in ProGRP after Cycle 1, and ProGRP remained stable or decreased after Cycle 2, the probability of finding progression on the interim computed tomography scan at the end of Cycle 2 was almost zero (sensitivity: 100%, specificity: 71%). Both ProGRP levels at baseline and at the end of first-line chemotherapy were prognostic; the latter provided a moderately improved hazard ratio of 2.43 (95% confidence interval: 1.33-4.46; n = 110) versus 1.87 (95% confidence interval: 1.04-3.37; n = 216). In summary, for patients with small-cell lung cancer and elevated baseline ProGRP levels, ProGRP may be a simple, reliable, and repeatable tool for monitoring response to chemotherapy and provide valuable prognostic information.


Asunto(s)
Neoplasias Pulmonares/sangre , Fragmentos de Péptidos/sangre , Carcinoma Pulmonar de Células Pequeñas/sangre , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Biomarcadores de Tumor/sangre , China , Europa (Continente) , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Pronóstico , Proteínas Recombinantes/sangre , Sensibilidad y Especificidad , Carcinoma Pulmonar de Células Pequeñas/diagnóstico por imagen , Carcinoma Pulmonar de Células Pequeñas/tratamiento farmacológico , Tomografía Computarizada por Rayos X
18.
Exp Physiol ; 105(4): 600-605, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32125032

RESUMEN

NEW FINDINGS: What is the central question of this study? What is the mechanism by which a bout of exercise increases subsequent insulin-stimulated vasodilatation? What is the main finding and its importance? Angiotensin-(1-7) through the Mas receptor participates in enhanced insulin-induced vasorelaxation after a bout of exercise in healthy rats. This new potential role of angiotensin-(1-7) could help in understanding how physical activity improves vascular insulin sensitivity in normal and insulin-resistant states. ABSTRACT: Exercise increases insulin-stimulated vasodilatation, but the mechanisms involved are unclear. This study was performed to investigate the possible involvement of angiotensin-(1-7) (Ang-(1-7)), a vasoactive peptide of the renin-angiotensin system (RAS), in enhanced vascular insulin sensitivity after a bout of exercise. Male Wistar rats were subjected to swimming for 2.5 h. After exercise, carbachol- or insulin-induced relaxation in aorta was assessed. Prior exercise improved insulin-stimulated vasorelaxation; however, this insulin-sensitizing effect was prevented by the selective Mas receptor (MasR; an Ang-(1-7) receptor) antagonist A779. Carbachol-mediated vascular relaxation was not modified by exercise. These results suggest that Ang-(1-7) acting through MasR participates in the enhancement of vascular insulin sensitivity after an exercise session. This new potential role of Ang-(1-7) could help in understanding how exercise improves vascular insulin sensitivity in normal and insulin-resistant states.


Asunto(s)
Angiotensina I/metabolismo , Resistencia a la Insulina/fisiología , Insulina/metabolismo , Fragmentos de Péptidos/metabolismo , Vasodilatación/fisiología , Animales , Masculino , Ratas , Ratas Wistar , Sistema Renina-Angiotensina/fisiología
19.
ISPRS J Photogramm Remote Sens ; 166: 68-81, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32747851

RESUMEN

Parameter retrieval and model inversion are key problems in remote sensing and Earth observation. Currently, different approximations exist: a direct, yet costly, inversion of radiative transfer models (RTMs); the statistical inversion with in situ data that often results in problems with extrapolation outside the study area; and the most widely adopted hybrid modeling by which statistical models, mostly nonlinear and non-parametric machine learning algorithms, are applied to invert RTM simulations. We will focus on the latter. Among the different existing algorithms, in the last decade kernel based methods, and Gaussian Processes (GPs) in particular, have provided useful and informative solutions to such RTM inversion problems. This is in large part due to the confidence intervals they provide, and their predictive accuracy. However, RTMs are very complex, highly nonlinear, and typically hierarchical models, so that very often a single (shallow) GP model cannot capture complex feature relations for inversion. This motivates the use of deeper hierarchical architectures, while still preserving the desirable properties of GPs. This paper introduces the use of deep Gaussian Processes (DGPs) for bio-geo-physical model inversion. Unlike shallow GP models, DGPs account for complicated (modular, hierarchical) processes, provide an efficient solution that scales well to big datasets, and improve prediction accuracy over their single layer counterpart. In the experimental section, we provide empirical evidence of performance for the estimation of surface temperature and dew point temperature from infrared sounding data, as well as for the prediction of chlorophyll content, inorganic suspended matter, and coloured dissolved matter from multispectral data acquired by the Sentinel-3 OLCI sensor. The presented methodology allows for more expressive forms of GPs in big remote sensing model inversion problems.

20.
Sensors (Basel) ; 20(18)2020 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-32948056

RESUMEN

Pansharpening is a technique that fuses a low spatial resolution multispectral image and a high spatial resolution panchromatic one to obtain a multispectral image with the spatial resolution of the latter while preserving the spectral information of the multispectral image. In this paper we propose a variational Bayesian methodology for pansharpening. The proposed methodology uses the sensor characteristics to model the observation process and Super-Gaussian sparse image priors on the expected characteristics of the pansharpened image. The pansharpened image, as well as all model and variational parameters, are estimated within the proposed methodology. Using real and synthetic data, the quality of the pansharpened images is assessed both visually and quantitatively and compared with other pansharpening methods. Theoretical and experimental results demonstrate the effectiveness, efficiency, and flexibility of the proposed formulation.

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