Exceptional genomic stability is one of the hallmarks of mouse embryonic stem (ES) cells. However, the genes contributing to this stability remain obscure. We previously identified Zscan4 as a ...specific marker for two-cell embryo and ES cells. Here we show that Zscan4 is involved in telomere maintenance and long-term genomic stability in ES cells. Only 5% of ES cells express Zscan4 at a given time, but nearly all ES cells activate Zscan4 at least once during nine passages. The transient Zscan4-positive state is associated with rapid telomere extension by telomere recombination and upregulation of meiosis-specific homologous recombination genes, which encode proteins that are colocalized with ZSCAN4 on telomeres. Furthermore, Zscan4 knockdown shortens telomeres, increases karyotype abnormalities and spontaneous sister chromatid exchange, and slows down cell proliferation until reaching crisis by passage eight. Together, our data show a unique mode of genome maintenance in ES cells.
The seroma is one of the most common complications in the axillary lymph nodal dissection (different surgical approaches have been tried to reduce the seroma incidence). In our study we evaluate the ...outcome of patients using or not the ultrasonic scalpel (Harmonic scalpel) according to a standardized surgical technique.
From January 2011 to December 2015 120 patients underwent axillary dissection for breast cancer. Patients were divided in two groups: patients belonging to the first group underwent Harmonic scalpel dissection and patients belonging to the second group underwent classical dissection. Each group consisted of 60 patients. Quadrantectomy (QUAD) was performed in 54 patients, 66 women underwent mastectomy. In all patients axillary dissection included the I, II and III level. We compared two groups in terms of: time of surgery, hematoma, drainage volume, days of sealing drainage, seroma formation, number of post-seroma aspirations, upper limb lymphedema, wound infections, post-operative pain.
Statistically significant results were obtained in terms of the total volume of the breast and axillary drainage in the two techniques. There were no significant differences in the two samples in terms of operative time incidence of seroma, post-operative hematoma, wound infection, and lymphedema of the upper limb.
The small number of cases did not allow us to reach definitive conclusions. The use of Harmonic scalpel seems to show smaller incidence of seroma and reduction of the amount of both breast and axillary drainages. Further studies are needed to define the real advantage in terms of cost benefit of using these devices in the axillary surgery.
The terminal ileum is the most involved tract in Crohn's disease. The obstruction in this location is the most frequent complication. Acute or chronic presentations can occur. Surgery finds a role in ...the management of chronic strictures and in acute clinical presentations with complications not improving with conservative therapy.
We investigate the outcome of patients with obstruction of the ileo-cecal bowel tract laparoscopically managed. It was analyzed the average operative time (OT), the conversion rate and the occurrence of re-operation due to surgical complications.
21 patients underwent an ileocecal resection for complicated Crohn's disease between January 2013 and December 2014. The admissions were performed in emergency in 42% of patients. The preintervention hospital stay was 5.8 (Sd 6.23). The mean operative time was 154 min (Sd 41). 28% of the procedures were converted to open surgery. The average hospital stay was 10 days (Sd 5) in uncomplicated patients. The morbidity rate was 28%. In 19% of cases a re-intervention was needed due to anastomotic leakage (3pts) and one hemoperitoneum for bleeding from the suture line.
Laparoscopy seems an affordable technique in the management of obstructive pattern of Crohn's disease. It should be the preferable approach in young patients that probably will be submitted to subsequent surgery for the same disease; in fact, the reduced adhesions formation provided by the less bowel manipulation make easy the subsequent access. Older patients had usually more post-operative morbidity and mortality mostly due to pre-existing conditions; if possible in these patients the treatment should be medical.
We study the existence of algebras of hypercyclic vectors for weighted backward shifts on Fréchet sequence spaces that are algebras when endowed with coordinatewise multiplication or with the Cauchy ...product. As a particular case, we obtain that the sets of hypercyclic vectors for Rolewicz's and MacLane's operators are algebrable.
High-energy electron beams generated by linear accelerators, typically in the range 6 to 20 MeV, are used in small field sizes for radiotherapy of localized superficial tumors. Unshielded silicon ...diodes (Si-D) are commonly considered suitable detectors for relative dose measurements in small electron fields due to their high spatial resolution. Recently, a novel synthetic single crystal diamond diode (SCDD) showed suitable properties for standard electron beams and small photon beams dosimetry. The aim of the present study is twofold: to characterize 6 to 15 MeV small electron beams shaped by using commercial tubular applicators with 2, 3, 4 and 5 cm diameter and to assess the dosimetric performance under such irradiation conditions of the novel SCDD dosimeter by comparison with commercially available dosimeters, namely a Si-D and a plane–parallel ionization chamber. Percentage depth dose curves, beam profiles and output factors (OFs) were measured. A good agreement among the dosimeters was observed in all of the performed measurements. As for the tubular applicators, two main effects were evidenced: (i) OFs larger than unity were measured for a number of field sizes and energies, with values up to about 1.3, that is an output 30% greater than that obtained at the 10 × 10 cm2 reference field; (ii) for each diameter of the tubular applicator a noticeable increase of the OF values was observed with increasing beam energy, up to about 100% in the case of the smaller applicator. This OF behavior is remarkably different from what typically observed for small blocked fields having the same size and energy as those used in this study. OFs for tubular applicators depend considerably on the field size, so interpolation is unadvisable to predict the linear accelerator output for such applicators whereas reliable high-resolution detectors, as the silicon and diamond diodes used in this work allow OF measurements with uncertainties of about 1%.
Although the gut is often considered the motor of sepsis, the relation between systemic inflammation and intestinal permeability in humans is not clear. We analyzed intestinal permeability during ...experimental endotoxemia in humans. Before and during experimental endotoxemia (Escherichia coli LPS, 2 ng/kg), using polyethylene glycol (PEG) as a permeability marker, intestinal permeability was analyzed in 14 healthy subjects. Enterocyte damage was determined by intestinal fatty acid binding protein. Endotoxemia induced an inflammatory response. Urinary PEGs 1,500 and 4,000 recovery increased from 38.8 +/- 6.3 to 63.1 +/- 12.5 and from 0.58 +/- 0.31 to 3.11 +/- 0.93 mg, respectively (P < 0.05). Intestinal fatty acid binding protein excretion was not affected by endotoxemia. The peak serum IL-10 concentrations correlated with the increase in PEG 1,500 recovery (r = 0.48, P = 0.027). Systemic inflammation results in an increased intestinal permeability. The increase in intestinal permeability is most likely caused by inflammation-induced paracellular permeability, rather than ischemia-mediated enterocyte damage.
High-frequency coastal radars (HFRs) have proved to be excellent tools for monitoring coastal circulation, providing synoptic, high spatial and temporal resolution surface current data in real time. ...They may also give detailed information on the surface wave field of coastal areas. An HFR has been operating in the Gulf of Naples (south-eastern Tyrrhenian Sea) since 2004. In this paper we show the results of their utilisation in the study of the Gulf dynamics and sea state, with a focus on potential applications in the context of operational oceanography.
Glioblastoma extensively infiltrates the brain; despite surgery and aggressive therapies, the prognosis is poor. A multidisciplinary approach combining mathematical, clinical and radiological data ...has the potential to foster our understanding of glioblastoma evolution in every single patient, with the aim of tailoring therapeutic weapons. In particular, the ultimate goal of biomathematics for cancer is the identification of the most suitable theoretical models and simulation tools, both to describe the biological complexity of carcinogenesis and to predict tumor evolution. In this report, we describe the results of a critical review about different mathematical models in neuro-oncology with their clinical implications. A comprehensive literature search and review for English-language articles concerning mathematical modelling in glioblastoma has been conducted. The review explored the different proposed models, classifying them and indicating the significative advances of each one. Furthermore, we present a specific case of a glioblastoma patient in which our recently proposed innovative mechanical model has been applied. The results of the mathematical models have the potential to provide a relevant benefit for clinicians and, more importantly, they might drive progress towards improving tumor control and patient's prognosis. Further prospective comparative trials, however, are still necessary to prove the impact of mathematical neuro-oncology in clinical practice.
Continuous bars of ductile iron are widely used for parts produced by machining processes, for example, hydraulic manifolds, hydraulic cylinder pistons, bushings, and pump housings. The main reasons ...for the selection of ductile iron bars are the high strength, stiffness, toughness, wear resistance, cost, and machinability. Concerning this last property, the best machinability is obtained for a ductile iron with a predominantly soft ferritic matrix. The rate of the solid-state transformation of austenite into ferrite, the so called “stable eutectoid reaction,” is dependent on the diffusion distance from the austenite to graphite particles, in other words, on the maximum distance between the graphite particles. If this distance increases, the time for the reaction may not be sufficient, and a “metastable eutectoid reaction” can occur, with the decomposition of austenite into pearlite, a mixture of soft ferrite with iron carbide. This constituent, called pearlite, shows higher hardness than ferrite, and so it must be machined under different conditions compared with a ferrite matrix. Thus, the distance between the graphite particles, measured by the number of graphite particles per unit area, determines the type of ductile iron matrix. The number of graphite particles is governed mainly by the solidification speed. In the continuous casting of bars of ductile iron, there is a variation in the solidification speed from the surface of the bar to the center of the section, decreasing toward the center. This is particularly important in thick sections, where the difference in the solidification speed is significant, leading to a variation in the microstructure from the surface to the center. This variation in the microstructure was the focus of this study, measuring various parameters connected to machinability, such as torque, power consumption, tool life (with tool wear analysis), and surface roughness. The goal was to show that the machining conditions must be changed when machining different positions on the section of a thick continuous ductile iron bar. Lower torque and shorter tool life were obtained when cutting the core in relation to the periphery region. However, in terms of power consumption and surface roughness, there was no statistical difference between the regions evaluated during the milling process. The variability of the machining output parameters is related to the mechanical properties along the cross section of the bars.
PDF
