Data Fusion for QRS Complex Detection in Multi-Lead Electrocardiogram Recordings

Heart diseases are the main cause of death worldwide. The first step in the diagnose of these diseases is the analysis of the electrocardiographic (ECG) signal. In turn, the ECG analysis begins with the detection of the QRS complex, which is the one with the most energy in the cardiac cycle. Numerous methods have been proposed in the bibliography for QRS complex detection, but few authors have analyzed the possibility of taking advantage of the information redundancy present in multiple ECG leads (simultaneously acquired) to produce accurate QRS detection. In our previous work we presented such an approach, proposing various data fusion techniques to combine the detections made by an algorithm on multiple ECG leads. In this paper we present further studies that show the advantages of this multi-lead detection approach, analyzing how many leads are necessary in order to observe an improvement in the detection performance. A well known QRS detection algorithm was used to test the fusion techniques on the St. Petersburg Institute of Cardiological Technics database. Results show improvement in the detection performance with as little as three leads, but the reliability of these results becomes interesting only after using seven or more leads. Results were evaluated using the detection error rate (DER). The multi-lead detection approach allows an improvement from DER = 3:04% to DER = 1:88%. Further works are to be made in order to improve the detection performance by implementing further fusion steps

Optimalization of preparation of apo-cytochrome b5 utilizing apo-myoglobin

Cytochrome b5 (cyt b5), a component of endoplasmic reticulum membrane, plays a role in modulation of enzymatic activity of some cytochrome P450 (CYP) enzymes. The effect of apo-cytochrome b5 on this enzymatic system has not been investigated in details, because preparation of cyt b5 as a pure protein failed in many laboratories. In order to prepare the native apo-cytochrome b5 in a large scale we utilized a protein with higher affinity toward the heme; the apo-myoglobin from the equine skeletal muscle. In the first step, we extracted heme moiety from the native myoglobin by butanone extraction. Than the effect of pH on spontaneous heme release from both proteins was investigated: purified rabbit cyt b5 as well as equine skeletal muscle myoglobin. The prepared apo-myoglobin was incubated with the cyt b5 and heme transfer was monitored as a shift of absorption maximum from 413 to 409 nm in pH varying between 3–6 (10 mM KH2PO4, pH 3–6). Here, we obtained 43 mg of the equine skeletal muscle apo-myoglobin (43% yield). The optimal pH range for heme transfer from cyt b5 into apo-myoglobin was between 4.2 and 5. Native apo-cytochrome b5 was successfully prepared using procedure described here

How allosteric control of Staphylococcus aureus penicillin binding protein 2a enables methicillin resistance and physiological function

6 pags, 4 figs, 1 tabThe expression of penicillin binding protein 2a (PBP2a) is the basis for the broad clinical resistance to the β-lactam antibiotics by methicillin-resistant Staphylococcus aureus (MRSA). The highmolecular mass penicillin binding proteins of bacteria catalyze in separate domains the transglycosylase and transpeptidase activities required for the biosynthesis of the peptidoglycan polymer that comprises the bacterial cell wall. In bacteria susceptible to β-lactam antibiotics, the transpeptidase activity of their penicillin binding proteins (PBPs) is lost as a result of irreversible acylation of an active site serine by the β-lactam antibiotics. In contrast, the PBP2a of MRSA is resistant to β-lactam acylation and successfully catalyzes the DD-transpeptidation reaction necessary to complete the cell wall. The inability to contain MRSA infection with β-lactam antibiotics is a continuing public health concern. We report herein the identification of an allosteric binding domain - a remarkable 60 Å distant from the DD-transpeptidase active site - discovered by crystallographic analysis of a soluble construct of PBP2a. When this allosteric site is occupied, a multiresidue conformational change culminates in the opening of the active site to permit substrate entry. This same crystallographic analysis also reveals the identity of three allosteric ligands: muramic acid (a saccharide component of the peptidoglycan), the cell wall peptidoglycan, and ceftaroline, a recently approved anti-MRSA β-lactam antibiotic. The ability of an anti-MRSA β-lactam antibiotic to stimulate allosteric opening of the active site, thus predisposing PBP2a to inactivation by a second β-lactam molecule, opens an unprecedented realm for β-lactam antibiotic structure-based design.Work in the United States was supported by National Institutes of Health Grants AI090818 and AI104987, and work in Spain was supported by Grants BFU2011-25326 (from the Spanish Ministry of Economy and Competitiveness) and S2010/BMD-2457 (from the Autonomous Government of Madrid)

Accommodating a Non-Conservative Internal Mutation by WaterMediated Hydrogen-Bonding Between β-Sheet Strands: A Comparison of Human and Rat Type B (Mitochondrial) Cytochrome b5

Mammalian type B (mitochondrial) cytochromes b5 exhibit greater amino acid sequence diversity than their type A (microsomal) counterparts, as exemplified by the type B proteins from human (hCYB5B) and rat (rCYB5B). The comparison of X-ray crystal structures of hCYB5B and rCYB5B reported herein reveals a striking difference in packing involving the five-stranded β-sheet, attributable to fully buried residue 21 in strand β4. The greater bulk of Leu21 in hCYB5B in comparison to Thr21 in rCYB5B results in a substantial displacement of the first two residues in β5, and consequent loss of two of the three hydrogen bonds between β5 and β4. Hydrogen-bonding between the residues is instead mediated by two well-ordered, fully buried water molecules. In a 10 ns molecular dynamics simulation, one of the buried water molecules in the hCYB5B structure exchanged readily with solvent via intermediates having three water molecules sandwiched between β4 and β5. When the buried water molecules were removed prior to a second 10 ns simulation, β4 and β5 formed persistent hydrogen bonds identical to those in rCYB5B, but the Leu21 side chain was forced to adopt a rarely observed conformation. Despite the apparently greater ease of water access to the interior of hCYB5B than of rCYB5B suggested by these observations, the two proteins exhibit virtually identical stability, dynamic and redox properties. The results provide new insight into the factors stabilizing the cytochrome b5 fold

Structural characterization of PaaX, the main repressor of the phenylacetate degradation pathway in Escherichia coli W: A novel fold of transcription regulator proteins

15 p.-8 fig.-2 tab.PaaX is a transcriptional repressor of the phenylacetic acid (PAA) catabolic pathway, a central route for bacterial aerobic degradation of aromatic compounds. Induction of the route is achieved through the release of PaaX from its promoter sequences by the first compound of the pathway, phenylacetyl-coenzyme A (PA-CoA). We report the crystal structure of PaaX from Escherichia coli W. PaaX displays a novel type of fold for transcription regulators, showing a dimeric conformation where the monomers present a three-domain structure: an N-terminal winged helix-turn-helix domain, a dimerization domain similar to the Cas2 protein and a C-terminal domain without structural homologs. The domains are separated by a crevice amenable to harbour a PA-CoA molecule. The biophysical characterization of the protein in solution confirmed several hints predicted from the structure, i.e. its dimeric conformation, a modest importance of cysteines and a high dependence of solubility and thermostability on ionic strength. At a moderately acidic pH, the protein formed a stable folding intermediate with remaining α-helical structure, a disrupted tertiary structure and exposed hydrophobic patches. Our results provide valuable information to understand the stability and mechanism of PaaX and pave the way for further analysis of other regulators with similar structural configurations.This research was funded by the following sources: Grants PID2019-105126RB-I00, PID2022-139209OB-C21 (MCIN/AEI/10.13039/501100011033/and ERDF A way of making Europe), TED2021-129747B-C22 (AEI/10.13039/501100011033/NextGenerationEU/PRTR) and CIBER-Consorcio Centro de Investigación Biomédica en Red (CIBERES, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación, Spain) to JMS; grants PID2020-115331GB-100 funded by MCIN/AEI/10.13039/501100011033 and CRSII5_198737/1 (Swiss National Science Foundation) to JAH; grant PID2021-128751NB-I00 (MICINN/AEI/FEDER/UE) to IU, and grant RYC2021-030916-I by the Spanish Agencia Estatal de Investigación to RM. VMH-R was supported by a FPU PhD fellowship from Spanish Ministerio de Educación y Ciencia.Peer reviewe

Higher Plant Cytochrome b5 Polypeptides Modulate Fatty Acid Desaturation

BACKGROUND: Synthesis of polyunsaturated fatty acids (PUFAs) in the endoplasmic reticulum of plants typically involves the fatty acid desaturases FAD2 and FAD3, which use cytochrome b(5) (Cb5) as an electron donor. Higher plants are reported to have multiple isoforms of Cb5, in contrast to a single Cb5 in mammals and yeast. Despite the wealth of information available on the roles of FAD2 and FAD3 in PUFA synthesis, information regarding the contributions of various Cb5 isoforms in desaturase-mediated reactions is limited. RESULTS: The present functional characterization of Cb5 polypeptides revealed that all Arabidopsis Cb5 isoforms are not similarly efficient in ω-6 desaturation, as evidenced by significant variation in their product outcomes in yeast-based functional assays. On the other hand, characterization of Cb5 polypeptides of soybean (Glycine max) suggested that similar ω-6 desaturation efficiencies were shared by various isoforms. With regard to ω-3 desaturation, certain Cb5 genes of both Arabidopsis and soybean were shown to facilitate the accumulation of more desaturation products than others when co-expressed with their native FAD3. Additionally, similar trends of differential desaturation product accumulation were also observed with most Cb5 genes of both soybean and Arabidopsis even if co-expressed with non-native FAD3. CONCLUSIONS: The present study reports the first description of the differential nature of the Cb5 genes of higher plants in fatty acid desaturation and further suggests that ω-3/ω-6 desaturation product outcome is determined by the nature of both the Cb5 isoform and the fatty acid desaturases

Recent development of respiratory rate measurement technologies

Respiratory rate (RR) is an important physiological parameter whose abnormity has been regarded as an important indicator of serious illness. In order to make RR monitoring simple to do, reliable and accurate, many different methods have been proposed for such automatic monitoring. According to the theory of respiratory rate extraction, methods are categorized into three modalities: extracting RR from other physiological signals, RR measurement based on respiratory movements, and RR measurement based on airflow. The merits and limitations of each method are highlighted and discussed. In addition, current works are summarized to suggest key directions for the development of future RR monitoring methodologies

Información Investigador: Altuve de Acuña, Fátima Mosniw

Resumen Curricular Licenciada en Bioanálisis, egresada de Universidad de Los Andes en el año 1993. Especialista en Citología Ginecológica y de la Glándula Mamaria en el año 1998. Bioanalista Citólogo al servicio del Laboratorio Docente, Asistencial y de Investigación Celina Sánchez Rincón de la Facultad de Farmacia y Bioanálisis. Miembro de la Sociedad Venezolana de Bioanalistas Especialistas y del Sindicato de Profesionales Universitarios (SIPRULA). Líneas de Investigación: Neoplasia del Cuello Uterino, Virus Papiloma Humano, Patología Mamaria y Patología Endometrial. Premio Estímulo al Investigador 2003 y 2005, ADG 2004 y 2006.UniversitarioUniversitario12 - 2005; 18 - 2003Neoplasia del cuello uterino. Virus papiloma humano. Patología mamaria y patología endometrial.Abril de 2007Licenciada en Bioanálisis+58 274 2403499;+58 274 2403552Facultad de Farmacia y BioanálisisPersonal de [email protected], [email protected]

Crystallization and preliminary X-ray diffraction studies of the transcriptional repressor PaaX, the main regulator of the phenylacetic acid degradation pathway in Escherichia coli W

3 p.-2 fig.-1 tab.PaaX is the main regulator of the phenylacetic acid aerobic degradation pathway in bacteria and acts as a transcriptional repressor in the absence of its inducer phenylacetyl-coenzyme A. The natural presence and the recent accumulation of a variety of highly toxic aromatic compounds owing to human pollution has created considerable interest in the study of degradation pathways in bacteria, the most important microorganisms capable of recycling these compounds, in order to design and apply novel bioremediation strategies. PaaX from Escherichia coliWwas cloned, overexpressed, purified and crystallized using the sitting-drop vapour-diffusion method at 291 K. Crystals grew from a mixture of 0.9 MLi2SO4 and 0.5 Msodium citrate pH 5.8. These crystals, which belonged to the monoclinic space group C2 with unit-cell parameters a = 167.88, b = 106.23, c = 85.87 A ° , = 108.33 , allowed the collection of an X-ray data set to 2.3 A ° resolution.This work was supported by grants BIO2003-05309-C04-04, BFU2005-01645 and BIO2007-67304-C02-02 from the Spanish Ministry of Science. This is a product of the ‘Factoría Española de Cristalización’ Ingenio/Consolider 2010 project.Peer reviewe

Hallazgos histopatológicos asociados a células glandulares atípicas.

NUESTRO COMPROMISO Conciente del papel fundamental que juega la Revista de la Facultad de Farmacia como órgano de difusión de las actividades de investigación que se llevan a cabo en nuestra facultad y otras facultades de la ULA, así como de otras instituciones del país, el Comité Editorial, recién designado, adquirió el compromiso de asumir y cumplir sus funciones cabalmente, con el objetivo de actualizar la revista de acuerdo a los estándares nacionales e internacionales de comunicación científica. En el transcurrir de estos cuarenta y ocho años, que tiene la Revista de la Facultad de Farmacia de fundada, se han introducido varias modificaciones y actualizaciones dirigidas en su oportunidad, por la desinteresada labor de los comités anteriores, que han sabido plasmar en ella, importantes contribuciones para su mantenimiento en el tiempo. Recientemente, el CDCHT a través de su Comisión de Publicaciones, evaluó las fortalezas y debilidades de 38 revistas, en el marco del plan de mejoramiento y proyección de las publicaciones periódicas que financian. Con respecto a la Revista de la Facultad de Farmacia se observa, que si bien algunos indicadores, tales como visibilidad internacional y nacional, potencialidad y normalización, no variaron mucho en los últimos años, por lo menos, mantuvieron un índice mayor al 70%, resultado que la clasificó como una revista tipo B. Por otra parte, el Vicerrectorado Académico en acto celebrado días atrás, otorgó un reconocimiento a la Revista de la Facultad de Farmacia por encontrarse entre las diez revistas más visitadas en el Repositorio Institucional SABER ULA durante el período 2005-2006. Todavía hay trabajo por hacer; sin embargo, elevar la calidad global de la Revista de la Facultad de Farmacia no es un compromiso solo del Comité Editorial, es un compromiso de la planta profesoral de la Facultad, a través de su participación rigurosa como autor o árbitro, y compromiso también de sus autoridades por el necesario apoyo institucional. Dra. Beatriz Nieves BlancoHallazgos histopatológicos asociados a células glandulares atípicas.Toro de Méndez, Morelva; López de Sánchez, Mercedes; Omaña, Tatyana; Altuve, Fátima y Guillén Ferraro, MorellaValores de referencia pediátricos para los parámetros bioquímicos glucosa y fosfatasa alcalina en una escuela rural del estado Mérida, Venezuela.Cadenas, Johana; Araujo, Liliana; Labrador, Carmen Zulay y Peña, JesúsVerificación de los valores asignados a dos sueros controles comerciales mediante una evaluación externa de la calidad.Rodríguez, Norys; Velázquez, Yarima; Rodríguez, Elymar; Ramírez, César; Molina, Luis y González, SoniaDetección de portadores de Staphylococcus aureus resistente a meticilina en una unidad de alto riesgo neonatal.Detection of Staphylocococcus aureus methicillin resistant carriers in highrisk neonatal unit.Alviárez, Evelyn; Velazco, Elsa; Nieves Blanco, Beatriz; Vivas, Gladis y Gutiérrez, BettyDeterminación de plomo en preparados farmacéuticos de origen natural por voltamperometía de onda cuadrada de redisolución anódica.Menolasina, Sabino; Lobaton, Maria; Lozano, Carmen y Molina, EumelyElaboración de una crema para uso tópico a base de Urtica dioica L.Signorelli, Isabella e Isla, MarylenlidÍndice [email protected]@yahoo.es, [email protected]@ula.ve, [email protected] analíticosemestra