The impact of endodontic anatomy on clinical practice: a micro-CT study and tribute to Prof. Francesco Riitano

Aim: To evaluate the quality of root canal preparation using two different mechanical NiTi systems. Methodology: 40 maxillary and mandibular molars were selected. Specimens were randomly assigned to two groups and were scanned using a micro-computed tomography scanner before and after root canal preparation that was performed using ProFile instrument sequence and Reciproc single file technique. Each system was used to obtain an optimal apical size for each specimen, following common clinical guidelines. 3D models were reconstructed and evaluated for volume, areas and root canal axis. The total volume of dentine removed and the volume of the coronal, middle and apical thirds of each root canal were calculated, as well as the average deviation of the root canal axis at different levels and the values compared. Student t-test was used to determine the difference between the two experimental groups (P < 0.05). A qualitative evaluation of root canal preparation was also performed. Results: No statistically significant differences were noted between the groups in the volume of dentine removed after root canal preparation, except for the volume of the coronal third (P < 0.05) and the volume of the apical third (P < 0.05) of the disto-buccal canal of maxillary molars and in the mesial canals of mandibular molars, where ProFile instruments produced significantly less enlarged canal volume in the apical third and more enlarged canal volume in the coronal third (P < 0.05). No statistically significant differences were found in the root canal axis deviation. Conclusions: Under the conditions of this study, both the systems analyzed were able to prepare molar teeth with similar amount of dentine removal and a relatively low risk of procedural errors

Multi- to Unilamellar Transitions in Catanionic Vesicles

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Time-Resolved Small-Angle X-Ray Scattering Study of the Early Formation of Amyloid Protofibrils on a Apomyoglobin Mutant

The description of the fibrillogenesis pathway and the identification of “on-pathwayâ or â off-pathwayâ intermediates are key issues in amyloid research as they are concerned with the mechanism for onset of certain diseases and with therapeutic treatments. Recent results on the fibril formation process revealed an unexpected complexity both in the number and in the types of species involved, but the early aggregation events are still largely unknown, mainly because of their experimental inaccessibility. To provide information on the early stage events of self-assembly of an amyloidogenic protein, during the so-called lag phase, stopped-flow time-resolved small angle x-ray scattering (SAXS) experiments were performed. Using a global fitting analysis, the structural and aggregation properties of the apomyoglobin W7FW14F mutant, which is monomeric and partly folded at acidic pH but forms amyloid fibrils after neutralization, were derived from the first few milliseconds onward. SAXS data indicated that the first aggregates appear in less than 20 ms after the pH jump to neutrality and further revealed the simultaneous presence of diverse species. In particular, worm-like unstructured monomers, very large assemblies, and elongated particles were detected, and their structural features and relative concentrations were derived as a function of time on the basis of our model. The final results show that, during the lag phase, early assembling occurs due to the presence of transient monomeric species very prone to association and through successive competing aggregation and rearrangement processes leading to coexisting on-pathway and off-pathway transient species

Treatment of doxorubicin resistant MCF7/Dx cells with nitric oxide causes histone glutathionylation and reversal of drug resistance.

Acquired drug resistance was found to be suppressed in the doxorubicin-resistant breast cancer cell line MCF7/Dx after pre-treatment with GSNO (nitrosoglutathione). The effect was accompanied by enhanced protein glutathionylation and accumulation of doxorubicin in the nucleus. Among the glutathionylated proteins, we identified three members of the histone family; this is, to our knowledge, the first time that histone glutathionylation has been reported. Formation of the potential NO donor dinitrosyl–diglutathionyl–iron complex, bound to GSTP1-1 (glutathione transferase P1-1), was observed in both MCF7/Dx cells and drug-sensitive MCF7 cells to a similar extent. In contrast, histone glutathionylation was found to be markedly increased in the resistant MCF7/Dx cells, which also showed a 14-fold higher amount of GSTP1-1 and increased glutathione concentration compared with MCF7 cells. These results suggest that the increased cytotoxic effect of combined doxorubicin and GSNO treatment involves the glutathionylation of histones through a mechanism that requires high glutathione levels and increased expression of GSTP1-1. Owing to the critical role of histones in the regulation of gene expression, the implication of this finding may go beyond the phenomenon of doxorubicin resistance

Understanding interaction properties in b-lactoglobulin in solution

We are studying the effects of increasing pressures on b-lactoglobuline (BLG), a protein belonging to the lipocaline family whose function in vivo is still unclear. Small Angle Neutron and X-Ray Scattering (SANS and SAXS) experiments have been performed to evaluate both structural modification and protein–protein effective interactions in different experimental conditions

Fast Room Temperature Very Low Field-Magnetic Resonance Imaging System Compatible with MagnetoEncephaloGraphy Environment.

In recent years, ultra-low field (ULF)-MRI is being given more and more attention, due to the possibility of integrating ULF-MRI and Magnetoencephalography (MEG) in the same device. Despite the signal-to-noise ratio (SNR) reduction, there are several advantages to operating at ULF, including increased tissue contrast, reduced cost and weight of the scanners, the potential to image patients that are not compatible with clinical scanners, and the opportunity to integrate different imaging modalities. The majority of ULF-MRI systems are based, until now, on magnetic field pulsed techniques for increasing SNR, using SQUID based detectors with Larmor frequencies in the kHz range. Although promising results were recently obtained with such systems, it is an open question whether similar SNR and reduced acquisition time can be achieved with simpler devices. In this work a room-temperature, MEG-compatible very-low field (VLF)-MRI device working in the range of several hundred kHz without sample pre-polarization is presented. This preserves many advantages of ULF-MRI, but for equivalent imaging conditions and SNR we achieve reduced imaging time based on preliminary results using phantoms and ex-vivo rabbits heads

Expanded measurements from station Lindenberg (2016-08)

The prototypes of ultra-low-field (ULF) MRI scanners developed in recent years represent new, innovative, cost-effective and safer systems, which are suitable to be integrated in multi-modal (Magnetoencephalography and MRI) devices. Integrated ULF-MRI and MEG scanners could represent an ideal solution to obtain functional (MEG) and anatomical (ULF MRI) information in the same environment, without errors that may limit source reconstruction accuracy. However, the low resolution and signal-to-noise ratio (SNR) of ULF images, as well as their limited coverage, do not generally allow for the construction of an accurate individual volume conductor model suitable for MEG localization. Thus, for practical usage, a high-field (HF) MRI image is also acquired, and the HF-MRI images are co-registered to the ULF-MRI ones. We address here this issue through an optimized pipeline (SWIM—Sliding WIndow grouping supporting Mutual information). The co-registration is performed by an affine transformation, the parameters of which are estimated using Normalized Mutual Information as the cost function, and Adaptive Simulated Annealing as the minimization algorithm. The sub-voxel resolution of the ULF images is handled by a sliding-window approach applying multiple grouping strategies to down-sample HF MRI to the ULF-MRI resolution. The pipeline has been tested on phantom and real data from different ULF-MRI devices, and comparison with well-known toolboxes for fMRI analysis has been performed. Our pipeline always outperformed the fMRI toolboxes (FSL and SPM). The HF–ULF MRI co-registration obtained by means of our pipeline could lead to an effective integration of ULF MRI with MEG, with the aim of improving localization accuracy, but also to help exploit ULF MRI in tumor imaging.Peer reviewe