Factores de Riesgo Asociados a Sepsis Neonatal en Recién Nacidos en el Hospital Victoria Motta,Ciudad de Jinotega,II Semestre 2014

En el presente estudio se determinan los principales factores de riesgo asociados a Sepsis Neonatal en el Hospital “Victoria Motta”, Jinotega. Durante el II semestre 2014, 646 Neonatos fueron ingresados al servicio de neonatología, 156 se etiquetaron como sospechosos de sepsis. Se analizó una muestra de 193 Neonatos, 64 casos y 129 controles. Fueron analizados los expedientes de Neonatos con/sin signos de infección, con/sin diagnóstico de sepsis y los expedientes de mujeres puérperas. Los factores más influyentes son: una edad gestacional entre 22 y 36 semanas (OR: 6.4 IC: 2.44-17.92) junto con un bajo peso al nacer (OR: 2.74 IC: 1.22-6.12), la Ruptura Prematura de Membrana mayor de 18 horas (OR: 5.19 IC: 2.33-12-03), seguida de Infecciones del Tracto Urinario (OR: 3.97 IC: 2.01-7.93). Así, la hipótesis de que los Neonatos de madres que presentaron Infección del Tracto Urinario durante el nacimiento tienen tres veces mayor riesgo de presentar Sepsis Neonatal, no es rechazada. Se recomienda al SILAIS Jinotega, Hospital “Victoria Motta” y Atención Primaria mejorar el monitoreo, asepsia y antisepsia en áreas de atención de Neonatos, y la educación del personal de salud y la población en genera

Predicción de supervivencia de tres escalas pronósticas en pacientes cirróticos con sangrado digestivo alto de etiología variceal en el Hospital Doctor Fernando Vélez Paiz, enero 2018 a diciembre de 2021

Predicción de supervivencia de tres escalas pronósticas en pacientes cirróticos con sangrado digestivo alto de etiología variceal en el hospital Doctor Fernando Vélez Paiz durante el periodo de enero 2018 a diciembre de 2020. Métodos: Se realizó un estudio de cohorte retrospectivo, analítico, con orientación longitudinal. Se utilizaron fichas de recolección de datos y para el análisis estadístico el sistema Microsoft Excel 2013 y SPSS versión 28.0. Las variables se compararon mediante U-Mann Whitney. Se calcularon curvas ROC (Receiver Operating Curves) para cada una de las escalas evaluadas y los valores se expresaron mediante c-estadística. Con los mejores puntos de corte obtenidos de cada escala se realizó análisis de supervivencia por medio de curvas de Kaplan-Meier y prueba de log-rank. Se consideró significativa una p = 0.0

The reverse gyrase helicase-like domain is a nucleotide-dependent switch that is attenuated by the topoisomerase domain

Reverse gyrase is a topoisomerase that introduces positive supercoils into DNA in an ATP-dependent manner. It is unique to hyperthermophilic archaea and eubacteria, and has been proposed to protect their DNA from damage at high temperatures. Cooperation between its N-terminal helicase-like and the C-terminal topoisomerase domain is required for positive supercoiling, but the precise role of the helicase-like domain is currently unknown. Here, the characterization of the isolated helicase-like domain from Thermotoga maritima reverse gyrase is presented. We show that the helicase-like domain contains all determinants for nucleotide binding and ATP hydrolysis. Its intrinsic ATP hydrolysis is significantly stimulated by ssDNA, dsDNA and plasmid DNA. During the nucleotide cycle, the helicase-like domain switches between high- and low-affinity states for dsDNA, while its affinity for ssDNA in the ATP and ADP states is similar. In the context of reverse gyrase, the differences in DNA affinities of the nucleotide states are smaller, and the DNA-stimulated ATPase activity is strongly reduced. This inhibitory effect of the topoisomerase domain decelerates the progression of reverse gyrase through the nucleotide cycle, possibly providing optimal coordination of ATP hydrolysis with the complex reaction of DNA supercoiling

Mechanistic studies of the modulation of cleavage activity of topoisomerase I by DNA adducts of mono- and bi-functional PtII complexes

Using electrophoresis and replication mapping, we show that the presence of DNA adducts of bifunctional antitumor cisplatin or monodentate [PtCl(dien)]Cl (dien = diethylenetriamine) in the substrate DNA inhibits eukaryotic topoisomerase 1 (top1) action, the adducts of cisplatin being more effective. The presence of camptothecin in the samples of platinated DNA markedly enhances effects of Pt–DNA adducts on top1 activity. Interestingly, the effects of Pt–DNA adducts on the catalytic activity of top1 in the presence of camptothecin differ depending on the sequence context. A multiple metallation of the short nucleotide sequences on the scissile strand, immediately downstream of the cleavage site impedes the cleavage by top1. On the other hand, DNA cleavage by top1 at some cleavage sites which were not platinated in their close proximity is notably enhanced as a consequence of global platination of DNA. We suggest that this enhancement of DNA cleavage by top1 may consist in its inability to bind to other cleavage sites platinated in their close neighborhood; thus, more molecules of top1 may become available for cleavage at the sites where top1 normally cleaves and where platination does not interfere

The modulation of topoisomerase I-mediated DNA cleavage and the induction of DNA–topoisomerase I crosslinks by crotonaldehyde-derived DNA adducts

Crotonaldehyde is a representative α,β-unsaturated aldehyde endowed of mutagenic and carcinogenic properties related to its propensity to react with DNA. Cyclic crotonaldehyde-derived deoxyguanosine (CrA-PdG) adducts can undergo ring opening in duplex DNA to yield a highly reactive aldehydic moiety. Here, we demonstrate that site-specifically modified DNA oligonucleotides containing a single CrA-PdG adduct can form crosslinks with topoisomerase I (Top1), both directly and indirectly. Direct covalent complex formation between the CrA-PdG adduct and Top1 is detectable after reduction with sodium cyanoborohydride, which is consistent with the formation of a Schiff base between Top1 and the ring open aldehyde form of the adduct. In addition, we show that the CrA-PdG adduct alters the cleavage and religation activities of Top1. It suppresses Top1 cleavage complexes at the adduct site and induces both reversible and irreversible cleavage complexes adjacent to the CrA-PdG adduct. The formation of stable DNA–Top1 crosslinks and the induction of Top1 cleavage complexes by CrA-PdG are mutually exclusive. Lastly, we found that crotonaldehyde induces the formation of DNA–Top1 complexes in mammalian cells, which suggests a potential relationship between formation of DNA–Top1 crosslinks and the mutagenic and carcinogenic properties of crotonaldehyde

Plant 45S rDNA Clusters Are Fragile Sites and Their Instability Is Associated with Epigenetic Alterations

Our previous study demonstrated that 45S ribosomal DNA (45S rDNA) clusters were chromosome fragile sites expressed spontaneously in Lolium. In this study, fragile phenotypes of 45S rDNA were observed under aphidicolin (APH) incubation in several plant species. Further actinomycin D (ActD) treatment showed that transcriptional stress might interfere with chromatin packaging, resulting in 45S rDNA fragile expression. These data identified 45S rDNA sites as replication-dependent as well as transcription-dependent fragile sites in plants. In the presence of ActD, a dramatic switch to an open chromatin conformation and accumulated incomplete 5′ end of the external transcribed spacer (5′ETS) transcripts were observed, accompanied by decreased DNA methylation, decreased levels of histone H3, and increased histone acetylation and levels of H3K4me2, suggesting that these epigenetic alterations are associated with failure of 45S rDNA condensation. Furthermore, the finding that γ-H2AX was accumulated at 45S rDNA sites following ActD treatment suggested that the DNA damage signaling pathway was associated with the appearance of 45S rDNA fragile phenotypes. Our data provide a link between 45S rDNA transcription and chromatin-packaging defects and open the door for further identifying the molecular mechanism involved

Raman Spectroscopy of Some Basic Chloride Containing Minerals of Lead and Copper

Raman spectroscopy has been used to characterise several lead and mixed cationic-lead minerals including mendipite, perite, laurionite, diaboléite, boléite, pseudoboléite, chloroxiphite, and cumengéite. Raman spectroscopy enables their vibrational spectra to be compared. The low wavenumber region is characterised by the bands assigned to cation-chloride stretching and bending modes. Phosgenite is a mixed chloride-carbonate mineral and a comparison is made with the molecular structure of the aforementioned minerals. Each mineral shows different hydroxyl-stretching vibrational patterns, but some similarity exists in the Raman spectra of the hydroxyl deformation modes. Raman spectroscopy lends itself to the study of these types of minerals in complex mineral systems involving secondary mineral formation