Desmineralización de la Dentina Humana Producida por Irrigantes Endodónticos Combinados

El objetivo de este trabajo fue evaluar el efecto de soluciones de irrigación endodónticas solas y combinadas sobre iones calcio y fosfato de la dentina radicular ex vivo. Se emplearon 56 discos de dentina obtenidos del tercio medio radicular de premolares inferiores unirradiculares extraídos por razones ortodóncicas. Los discos se dividieron al azar en 8 grupos (n=7). Grupo I: agua destilada (AD), Grupo II: hipoclorito de sodio (NaClO) 1 %, Grupo III: EDTA 17 %, Grupo IV: ácido maleico (AM) 5 %, Grupo V: ácido acético (AA) 5 %, Grupo VI: EDTA 17 % + NaClO 1 %, Grupo VII: AM 5 % + NaClO 1 %, Grupo VIII: AA 5 % + NaClO 1 %. Los segmentos de dentina permanecieron en contacto a 37° C durante 5 min y 2,5 minutos en cada solución cuando se usaron en forma sucesiva. Se determinó la concentración de iones calcio de las soluciones mediante espectrometría de absorción atómica y la concentración de iones fosfatos mediante colorimetría (Wienner Lab.). Los resultados se expresaron en mg/ml/gr de tejido. Para el análisis estadístico se utilizó ANOVA y Test de Tukey. AA 5 % y EDTA 17 % se comportaron de manera similar utilizados solos durante 5 minutos, NaClO 1 % no mostró diferencias con el AD. AM 5 % eliminó significativamente más calcio y fosfato que todos los grupos. Todas las soluciones desmineralizaron la dentina, pero AM 5 % durante 5 min fue la solución que más afectó el componente inorgánico de la dentina.

The aim of the present study was to evaluate ex vivo irrigating solutions effect under calcium and phosphates dentin ions, using them alone and combined. In this study 56 dentin discs where used. They were obtained from middle third of mandibular single-root premolars extracted for orthodontics reasons. Discs were randomly divided into 8 groups (n:7). Group I: Distilled water (DW), Group II: 1 % sodium hypochlorite (NaOCl), Group III: 17 % EDTA, Group IV: 5 % maleic acid (MA), Group V: 5 % acetic acid (AA), Group VI: 17 % EDTA + 1 % NaOCl, Group VII: 5 % MA + 1 % NaOCl, Group VIII: 5 % AA + 1 % NaOCl. Dentin segments were kept in contact with irrigating solutions at 37°C for 5 minutes, when used alone, or for 2.5 minutes when used combined. After that, calcium ions (using absorption atomic spectrometry) and phosphorus ions (by colorimetry Wienner Lab.) were determined. Results were expressed in mg/ml/g tissue. Statistical analysis was performed by ANOVA and Tukey test. 5 % AA and 17 % EDTA eliminated similar concentrations of calcium and phosphates ions from dentin at 5 minutes exposure time, while 1 % NaOCl did not present statistical differences with control. 5 % MA eliminated significantly more calcium and phosphates ions than the rest of analyzed groups. Every tested solutions demineralized human dentin, but 5 % MA used for 5 minutes did it the most.

Could pulmonary low-dose radiation therapy be an alternative treatment for patients with COVID-19 pneumonia? Preliminary results of a multicenter SEOR-GICOR nonrandomized prospective trial (IPACOVID trial).

PURPOSE: To evaluate the efficacy and safety of lung low-dose radiation therapy (LD-RT) for pneumonia in patients with coronavirus disease 2019 (COVID-19). MATERIALS AND METHODS: Inclusion criteria comprised patients with COVID-19-related moderate-severe pneumonia warranting hospitalization with supplemental O2 and not candidates for admission to the intensive care unit because of comorbidities or general status. All patients received single lung dose of 0.5 Gy. Respiratory and systemic inflammatory parameters were evaluated before irradiation, at 24 h and 1 week after LD-RT. Primary endpoint was increased in the ratio of arterial oxygen partial pressure (PaO2) or the pulse oximetry saturation (SpO2) to fractional inspired oxygen (FiO2) ratio of at least 20% at 24 h with respect to the preirradiation value. RESULTS: Between June and November 2020, 36 patients with COVID-19 pneumonia and a mean age of 84 years were enrolled. Seventeen were women and 19 were men and all of them had comorbidities. All patients had bilateral pulmonary infiltrates on chest X­ray. All patients received dexamethasone treatment. Mean SpO2 pretreatment value was 94.28% and the SpO2/FiO2 ratio varied from 255 mm Hg to 283 mm Hg at 24 h and to 381 mm Hg at 1 week, respectively. In those who survived (23/36, 64%), a significant improvement was observed in the percentage of lung involvement in the CT scan at 1 week after LD-RT. No adverse effects related to radiation treatment have been reported. CONCLUSIONS: LD-RT appears to be a feasible and safe option in a population with COVID-19 bilateral interstitial pneumonia in the presence of significant comorbidities.

Human prostasomes from normozoospermic and non-normozoospermic men show a differential protein expression pattern.

Prostasomes are exosomes such as extracellular vesicles, produced in the prostatic epithelium and released into the seminal plasma, that play an important role enhancing male fertility. Although some studies have demonstrated that prostasomes have a rich proteomic content, it is still unclear if that proteomic content varies depending on the male fertility status. Prostasomes from 12 normozoospermic and 14 non-normozoospermic seminal samples were isolated by differential ultracentrifugation. Protein content was studied by quantitative mass spectrometry and compared between both cohorts. We identified 1282 proteins with 745 of them (57.8%) being present in all seven prostasome pools. Forty-seven of those commonly present proteins showed differential expression levels in both cohorts. Specifically, prostasomes from non-normozoospermic samples showed a pattern of protein underexpression for a group of proteins including several proteins from the spermatozoa's energy production pathways as well as some proteins directly implicated in sperm activity. Variations in prostasomal protein content levels may have a relevant correlation with male fertility and thus could be of great utility as a biomarker of fertility status.

Patterns of phase-dependent spiral wave attenuation in excitable media.

We show that introducing periodic planar fronts with long excitation duration can lead to spiral attenuation. The attenuation occurs periodically over cycles of several planar fronts, forming a variety of complex spatiotemporal patterns. We find that these attenuation patterns occur only at specific phases of the descending fronts relative to the rotational phase of the spiral. These patterns fall into two general classes, each defined by a specific expression for the number of attenuated spirals per cycle of planar fronts, and represented by a structured diagram in parameter space. The spiral attenuation patterns we observe remain stable in time and do not change during the evolution of the system.

System-size resonance in a binary attractor neural network.

System size resonance (SSR) is a phenomenon in which the response of a system is optimal for a certain finite size, but poorer as the size goes to zero or infinity. In order to show SSR effects in binary attractor neural networks, we study the response of a network, in the ferromagnetic phase, to an external, time-dependent stimulus. Under the presence of such a stimulus, the network shows SSR, as is demonstrated by the measure of the signal amplification both analytically and by simulation.

System size resonance in coupled noisy systems and in the Ising model.

We consider an ensemble of coupled nonlinear noisy oscillators demonstrating in the thermodynamic limit an Ising-type transition. In the ordered phase and for finite ensembles stochastic flips of the mean field are observed with the rate depending on the ensemble size. When a small periodic force acts on the ensemble, the linear response of the system has a maximum at a certain system size, similar to the stochastic resonance phenomenon. We demonstrate this effect of system size resonance for different types of noisy oscillators and for different ensembles---lattices with nearest neighbors coupling and globally coupled populations. The Ising model is also shown to demonstrate the system size resonance.

Efficacy of two techniques for endodontic instrumentation.

The aim of the present study was to compare the quality of preparation in curved and straight root canals employing 2 techniques, i.e. the step-back technique and the technique of Goerig, Michelich and Schultz. One hundred and thirty single-rooted human teeth were employed throughout. The walls of the root canals of these teeth were painted. Following instrumentation the roots were sectioned longitudinally. The sections were observed under a stereoscopic microscope SZ40 with a grid fitted in the eyepiece. The efficacy of instrumentation was evaluated using area of paint removed as the end-point. Statistical significance of the data was tested with the chi square test employing the Epi Info 5 software. There was no statistically significant difference between techniques for straight canals. The technique of Goerig, Michelich and Schultz was more effective than the step-back technique in the apical third of curved canals.

Efficacy of two techniques for endodontic instrumentation

The aim of the present study was to compare the quality of preparation in curved and straight root canals employing 2 techniques, i.e. the step-back technique and the technique of Goerig, Michelich and Schultz. One hundred and thirty single-rooted human teeth were employed throughout. The walls of the root canals of these teeth were painted. Following instrumentation the roots were sectioned longitudinally. The sections were observed under a stereoscopic microscope SZ40 with a grid fitted in the eyepiece. The efficacy of instrumentation was evaluated using area of paint removed as the end-point. Statistical significance of the data was tested with the chi square test employing the Epi Info 5 software. There was no statistically significant difference between techniques for straight canals. The technique of Goerig, Michelich and Schultz was more effective than the step-back technique in the apical third of curved canals.