Chemical genomics with pyrvinium identifies C1orf115 as a regulator of drug efflux.

Pyrvinium is a quinoline-derived cyanine dye and an approved anti-helminthic drug reported to inhibit WNT signaling and have anti-proliferative effects in various cancer cell lines. To further understand the mechanism by which pyrvinium is cytotoxic, we conducted a pooled genome-wide CRISPR loss-of-function screen in the human HAP1 cell model. The top drug-gene sensitizer interactions implicated the malate-aspartate and glycerol-3-phosphate shuttles as mediators of cytotoxicity to mitochondrial complex I inhibition including pyrvinium. By contrast, perturbation of the poorly characterized gene C1orf115/RDD1 resulted in strong resistance to the cytotoxic effects of pyrvinium through dysregulation of the major drug efflux pump ABCB1/MDR1. Interestingly, C1orf115/RDD1 was found to physically associate with ABCB1/MDR1 through proximity-labeling experiments and perturbation of C1orf115 led to mis-localization of ABCB1/MDR1. Our results are consistent with a model whereby C1orf115 modulates drug efflux through regulation of the major drug exporter ABCB1/MDR1.

Dynamical age differences among coeval star clusters as revealed by blue stragglers.

Globular star clusters that formed at the same cosmic time may have evolved rather differently from the dynamical point of view (because that evolution depends on the internal environment) through a variety of processes that tend progressively to segregate stars more massive than the average towards the cluster centre. Therefore clusters with the same chronological age may have reached quite different stages of their dynamical history (that is, they may have different 'dynamical ages'). Blue straggler stars have masses greater than those at the turn-off point on the main sequence and therefore must be the result of either a collision or a mass-transfer event. Because they are among the most massive and luminous objects in old clusters, they can be used as test particles with which to probe dynamical evolution. Here we report that globular clusters can be grouped into a few distinct families on the basis of the radial distribution of blue stragglers. This grouping corresponds well to an effective ranking of the dynamical stage reached by stellar systems, thereby permitting a direct measure of the cluster dynamical age purely from observed properties.

Oxygen adsorption on beta-cristobalite polymorph: ab initio modeling and semiclassical time-dependent dynamics.

The adsorption dynamics of atomic oxygen on a model beta-cristobalite silica surface has been studied by combining ab initio electronic structure calculations with a molecular dynamics semiclassical approach. We have evaluated the interaction potential of atomic and molecular oxygen interacting with an active Si site of a model beta-cristobalite surface by performing DFT electronic structure calculations. As expected, O is strongly chemisorbed, E(b) = 5.57 eV, whereas molecular oxygen can be weakly adsorbed with a high-energy barrier to the adsorption state of approximately 2 eV. The binding energies calculated for silica clusters of different sizes have revealed the local nature of the O,O(2)-silica interaction. Semiclassical collision dynamic calculations show that O is mainly adsorbed in single-bounce collisions, with a smaller probability for adsorption via a multicollision mechanism. The probability for adsorption/desorption (reflected) collisions at the three impact energies is small but not negligible at the higher energy considered in the trajectory calculations, about P(r) = 0.2 at E(kin) = 0.8 eV. The calculations give evidence of a complex multiphonon excitation-deexcitation mechanism underlying the dynamics of stable adsorption and inelastic reflection collisions.

High-throughput genome-wide phenotypic screening via immunomagnetic cell sorting.

Genome-scale functional genetic screens are used to identify key genetic regulators of a phenotype of interest. However, the identification of genetic modifications that lead to a phenotypic change requires sorting large numbers of cells, which increases operational times and costs and limits cell viability. Here, we introduce immunomagnetic cell sorting facilitated by a microfluidic chip as a rapid and scalable high-throughput method for loss-of-function phenotypic screening using CRISPR-Cas9. We used the method to process an entire genome-wide screen containing more than 108 cells in less than 1 h-considerably surpassing the throughput achieved by fluorescence-activated cell sorting, the gold-standard technique for phenotypic cell sorting-while maintaining high levels of cell viability. We identified modulators of the display of CD47, which is a negative regulator of phagocytosis and an important cell-surface target for immuno-oncology drugs. The top hit of the screen, the glutaminyl cyclase QPCTL, was validated and shown to modify the N-terminal glutamine of CD47. The method presented could bridge the gap between fluorescence-activated cell sorting and less flexible yet higher-throughput systems such as magnetic-activated cell sorting.

Essential Gene Profiles for Human Pluripotent Stem Cells Identify Uncharacterized Genes and Substrate Dependencies.

Human pluripotent stem cells (hPSCs) provide an invaluable tool for modeling diseases and hold promise for regenerative medicine. For understanding pluripotency and lineage differentiation mechanisms, a critical first step involves systematically cataloging essential genes (EGs) that are indispensable for hPSC fitness, defined as cell reproduction in this study. To map essential genetic determinants of hPSC fitness, we performed genome-scale loss-of-function screens in an inducible Cas9 H1 hPSC line cultured on feeder cells and laminin to identify EGs. Among these, we found FOXH1 and VENTX, genes that encode transcription factors previously implicated in stem cell biology, as well as an uncharacterized gene, C22orf43/DRICH1. hPSC EGs are substantially different from other human model cell lines, and EGs in hPSCs are highly context dependent with respect to different growth substrates. Our CRISPR screens establish parameters for genome-wide screens in hPSCs, which will facilitate the characterization of unappreciated genetic regulators of hPSC biology.

The mepsMAP server. Mapping epitopes on protein surface: mining annotated proteins.

For a growing number of biologists DNA or protein data are typically retrieved and managed on the Web, and not in the laboratory. A large number of bioinformatics datasets from primary and (thousands of) secondary databases are scattered on the Web in various formats. A biologist end-user might need to access and use tens of databases and tools every day. For this reason, the bioinformatics community is developing more and more service-oriented architectures (SOAs): software architecture of loosely coupled software services that can be accessed without knowledge of, or control over, their internal architecture. Data-processing and analysis tasks can be automated by having free access to bioinformatics Web services (WSs) that are the building blocks of the SOAs. In this paper we introduce a new bioinformatics Web server, mepsMAP (mapping epitopes on protein surface: Mining Annotated Proteins), developed to identify the recognition sites between antibodies and their cognate antigens. In some cases, the recognition site is represented by a continuous segment of the antigen sequence, but much more often the epitope is "conformational," i.e., the antibody recognizes the location and type of exposed antigen side chains that are not necessarily contiguous in the antigen's sequence, but brought together by its three-dimensional structure. A facility on the server allows the user to search putative conformational epitopes on protein surface, querying the system for proteins with a given annotation. The mepsMAP server has been implemented as a SOA composed by a database and a set of four WSs. We present here the software architecture of the system with a detailed description of the WS dataflow that has been optimized to provide the best computing performance while maintaining the easiest end-user access to the system via a Web interface.

Electron-attachment resonances of glycine zwitterions from quantum scattering calculations: modeling macrosolvation effects.

A computational study of the quantum dynamics for low-energy electrons scattered by the isolated zwitterionic species of the glycine molecule is carried out using a model interaction potential described in the main text. The macroscopic effects of water solvation on the target molecule in the electron scattering problem are described through a continuum polarizable model (CPCM) which modifies the target molecular structure. In such a way, realistic molecular orbitals depicting the glycine zwitterion in solution are used to model the electron-molecule interaction. The results of the calculations indicate the presence of five different transient negative ions (TNIs) formed at energies from the threshold and up to about 6 eV. Although no nuclear motion was explicitly considered in the ensuing decay processes, the analysis of the nodal structures and density distributions for the resonant excess electron wavefunctions over the molecular space suggests possible anionic fragmentations that produce (Gly-H)-, H-, -CO2-, and -NH3. The likely consequences of such releases into the medium are briefly discussed.

Medical survey of female boxing in Italy in 2002-2003.

BACKGROUND: Female boxing has been permitted in Italy since 2001. According to the latest Italian laws, athletes applying to become boxers have to pass a pre-participation medical examination. OBJECTIVE: To collect novel medical information from the pre-participation visits and mandatory pre-competition and post-competition examinations for all fights involving Italian female boxers in 2002-2003. METHODS: A retrospective study on all official female boxing competitions in Italy from January 2002 to October 2003 was conducted. A prospective study on 28 amateur female boxers was also carried out. RESULTS: Retrospective study: data from 664 examinations were collected. Pre-match examinations were negative. After competitions, 19/645 visits showed some injuries, with mild, soft tissue facial lesions, epistaxis, and hand-wrist problems being the most common. Prospective study: no major lesions were found during the study. One fibroadenoma, one ovarian cyst, and one intramural uterine myoma were found. One boxer was referred to a neurologist because of non-specific electroencephalographic (EEG) abnormalities, which persisted six months later. On a re-admission examination, which was needed because of a contest that was stopped because the referee judged that she was receiving blows to the head that were dangerous, one boxer showed non-specific EEG alterations and nystagmus. A cerebral magnetic resonance imaging scan was normal. She was allowed to participate in competitions again when her EEG returned to normal and clinical signs disappeared. Deviation of the nasal septum was quite common (68%). No major eye injuries were reported. CONCLUSION: Probably because of the correct preventive medical approach, female boxing is much safer than expected, and no major lesions (requiring hospital admission) were reported. Any lesions to the breast and reproductive system could not be considered to be boxing related.

Ring-breaking electron attachment to uracil: following bond dissociations via evolving resonances.

Calculations are carried out at various distinct energies to obtain both elastic cross sections and S-matrix resonance indicators (poles) from a quantum treatment of the electron scattering from gas-phase uracil. The low-energy region confirms the presence of pi(*) resonances as revealed by earlier calculations and experiments which are compared with the present findings. They turn out to be little affected by bond deformation, while the transient negative ions (TNIs) associated with sigma(*) resonances in the higher energy region ( approximately 8 eV) indeed show that ring deformations which allow vibrational redistribution of the excess electron energy into the molecular target strongly affect these shape resonances: They therefore evolve along different dissociative pathways and stabilize different fragment anions. The calculations further show that the occurrence of conical intersections between sigma(*) and pi(*)-type potential energy surfaces (real parts) is a very likely mechanism responsible for energy transfers between different TNIs. The excess electron wavefunctions for such scattering states, once mapped over the molecular space, provide nanoscopic reasons for the selective breaking of different bonds in the ring region.

Elite athletes: is survival shortened in boxers?

Moderate exercise and intense physical training are associated with increased life expectancy (LE). Boxing is characterized by intentional and repetitive head blows, sometimes causing brain injury, possibly reducing LE. We examined a sample of male athletes born between 1860 and 1930 selected from the international "hall of fame" inductees in baseball (n = 154), ice hockey (n = 130), tennis (n = 83), football (n = 81), boxing (n = 81), track and field (n = 59), basketball (n = 58), swimming (n = 37) and wrestling (n = 32). In boxing, we analyzed the number of disputed bouts/rounds and career records. Sports were also analyzed according to physiological demand and occurrence and kind of contact (intentional, unintentional). The Kaplan-Meier product limit method was used to compare survival curves (significance: p

H- desorption from uracil via metastable electron capture.

In this Letter we report an analysis of the quantum dynamics for the scattering of slow electrons off uracil molecules, leading to the formation of a trapped, metastable anionic state at around 9 eV of energy. This resonant state is seen to be capable of describing an anionic molecular precursor which can explain the desorption of the H- species observed in experiments on film deposited uracil samples.

AV blocking due to asynchronous vagal stimulation in rats.

The parasympathetic nervous system innervates the heart through two cervical vagal branches. The right vagal branch mainly influences the heart rate by the modulation of the rhythmogenesis of the sinoatrial node. The left branch predominantly influences the conduction properties of the atrioventricular (AV) node. We investigated the effect of asynchronous stimulation by the vagal nerves on the occurrence of irregularities in heart rate. In rats, the vagal nerves were isolated and cut. Different vagal stimulation patterns (continuous, pulsed) were applied. The heart was beating spontaneously under continuous vagal stimulation. In case of pulsed vagal stimulation, the atria were paced at different rates. Asynchronicity was induced by delaying the right stimulus with respect to the left stimulus (early right) or the left stimulus with respect to the right stimulus (early left). The value of the fraction of deviated R-R or P-Q intervals in the distribution in the histogram was used to characterize irregularities during a stimulation protocol (duration in case of continuous stimulation: 20 s; pulsed stimulation: 120 s). Under both stimulation patterns (continuous or pulsed), we found that early left vagal stimulation introduced a much larger fraction of deviated intervals in the R-R or P-Q histogram (in R-R: 29.1 +/- 4.9%; in P-Q: 12.90 +/- 1.95%) than early right vagal stimulation (in R-R: 7.4 +/- 2.0%; in P-Q: 1. 05 +/- 0.50%) or synchronous stimulation (in R-R: 8.2 +/- 3.6%; in P-Q: 2.15 +/- 0.75%). We conclude that early stimulation by the left vagal nerve can introduce irregularities in heart rate, mainly due to different degrees of AV nodal blockade.

Low-energy electron scattering by cubane: resonant states and Ramsauer-Townsend features from quantum calculations in the gas phase.

Calculations are carried out, using a nonempirical modeling of the interaction potential and solving the quantum scattering coupled channel equations, for low energy electron scattering from cubane (C8H8) molecules in the gas phase. Total integral cross sections are obtained and partial contributions are analyzed for the most important irreducible representations that describe the continuum electron in the Oh molecular symmetry. Several trapping resonances are found and analyzed in terms of the molecular-type features of the resonant electron states associated with them. A Ramsauer-Townsend minimum is also found and its possible behavior related to features of the scattering length as k --> 0.

Does early repolarization in the athlete have analogies with the Brugada syndrome?

AIMS: To re-examine the prevalence and presentation of early repolarization in athletes and to compare it with electrocardiographic abnormalities observed in patients with the Brugada syndrome. METHODS: Electrocardiograms of 155 male athletes and 50 sedentary controls were studied. Early repolarization was considered present if at least two adjacent precordial leads showed elevation of the ST segment > or =1 mm. Amplitude and morphology of ST elevation, the leads where it was present and the lead in which it showed its maximum value were analysed together with QRS duration, the presence of right ventricular activation delay, QT and QTc duration. Data were compared with those obtained by electrocardiograms of 23 patients with the Brugada syndrome. RESULTS: Early repolarization was found in 139 athletes (89%) and 18 controls (36%, P< or =0.025), being limited to right precordial leads in 42 (30%) athletes and 13 (72%) controls (P< or =0.001). Only 12 (8.6%) athletes and one control (5.5%) with early repolarization had an ST elevation 'convex toward the top' in right precordial leads, similar to that seen in the Brugada syndrome. In athletes the maximum ST elevation was greater (2.3+/-0.6 mm) than in the controls (1.2+/-0.8 mm; P< or =0.004) but significantly lower than in patients with the Brugada syndrome (4.4+/-0.7 mm; P< or =0.0001). Patients with the Brugada syndrome also had a greater QRS duration (0.11+/-0.02 s) than athletes (0.090+/-0.011 s; P< or =0.0001) with early repolarization. CONCLUSIONS: Early repolarization is almost always the rule in athletes but it is also frequent in sedentary males. Tracings somewhat simulating the Brugada syndrome were observed in only 8% of athletes without a history of syncope or familial sudden death. Significant differences exist between athletes with early repolarization and patients with the Brugada syndrome as regards the amplitude of ST elevation and QRS duration.

Prolonged asystolia in a young athlete: a case of sinus arrest during REM sleep.

A young asymptomatic male athlete came to our laboratory to be enrolled in a research protocol on physical fatigue. Routine clinical and cardiological evaluations including echocardiogram were in the normal range. Several consecutive cardiopulmonary tests showed a fairly good tolerance to exercise, with no symptoms even when the effort was abruptly arrested. On the other hand, Holter ECG recordings showed long nocturnal sinus pauses. As he was absolutely asymptomatic and free from any structural heart disease, he underwent a follow-up with repeated Holter monitorings for one year. During this period he decided on his own to stop practising sports; in spite of this sharp reduction in his overall physical activity, consecutive Holter monitorings showed that the sinus pauses were progressively increasing in duration (up to 9.2 seconds). With the hypothesis of a malignant vagotonia, he underwent a tilt test; however, we could not elicit any pauses or symptoms. The pauses grew longer over time; a endocavitary electrophysiologic test was performed, which showed no evidence of disease. To rule out the hypothesis of a sleep apnoea syndrome, he also underwent a polysomnography, including EEG, eye movement electromyography, arterial blood oxygen saturation and thoracic impedance: no alterations were detected with the exception of the sinus pauses, which appeared to be strictly linked to REM sleep, as suggested by the concurrent increase in rapid eye movements and desynchronized EEG. We hence made a diagnosis of sinus arrest during REM sleep (SAdRS), a very uncommon disease belonging to the parasomnias. Pauses were then quantified for one month by implanting a ECG loop recorder. As the patient became more and more upset and worried, and the pauses increased to nearly 12 seconds, we decided to implant a pacemaker, which is the only therapeutic option established in the literature for patients with SAdRS.