Coexistence of multiple sclerosis and brain tumors: a literature review.

Concurrent development of primary brain tumors and multiple sclerosis is quite rare. Only a few dozens of such comorbidity have been reported. Nevertheless, given the fact that such pathologies are characterized by similar clinical picture and neuroimaging findings, issues about diagnosis and differential diagnosis of such conditions often arise, which makes the problem relevant. A literature review was conducted using PubMed, by selecting articles on concurrent multiple sclerosis and brain tumors, particularly glial origin tumors, over the past 20 years (1989 to 2019). The search was performed in English, Russian, and Ukrainian using the following key words and terms: comorbidity, concomitance, multiple sclerosis, brain tumor, glioma, astrocytoma, glioblastoma.  The analysis included all articles on etiology, pathogenesis, clinical picture, diagnosis, differential diagnosis, neuroimaging, and pathomorphological assessment. After identifying all the articles that met the inclusion criteria and removing duplicate data, 35 literature sources on concurrent primary brain tumors and multiple sclerosis were selected. The conclusion on whether concurrent primary brain tumors and multiple sclerosis develop randomly or have common pathophysiological mechanisms is still under discussion. Potential causes of pathogenesis of both diseases include viral infection, chronic inflammation, neoplastic transformation, and involvement of neurotropic growth factors. The likelihood that two processes, demyelinating and neoplastic, can develop in parallel will never be underestimated. In such cases, strong clinical suspicion arises due to atypical clinical picture characterized by aggressive and rapidly growing neurological symptoms such as aphasia, spastic hemiparesis, epileptic seizures, or signs of intracranial hypertension. In MRI diagnosis, pathological findings such as single lesion of more than 2 cm; mass effect, edema, signal amplification in the form of ring-shaped shadow are the reasons for a more thorough examination and applying additional diagnostic methods: CT, MR spectroscopy, PET, CSF tests to determine oligoclonal antibodies and other markers content, cerebral biopsy. According to the literature, cases of concurrent primary brain tumors and multiple sclerosis are rare though described. Atypical clinical signs, neuroimaging data, and cerebral biopsy which is currently considered as the only method for making accurate diagnosis are helpful in the diagnostic process

Coexistence of multiple sclerosis and brain tumours: Case report and review

In the present report, a review of the literature on the combination of multiple sclerosis and brain tumours is performed. Additionally, the frequency of such combination, possible etiopathogenetic mechanisms, current diagnostic criteria and treatment approaches are reviewed. Furthermore, the case of a 30-year-old man with multiple sclerosis and anaplastic astrocytoma of the right temporal lobe is described in detail. Specifically, the patient underwent a series of tests, including laboratory analyses of blood and cerebrospinal fluid, brain MRI in various modes, MR spectroscopy and excised tumour’s pathohistological and immunohistochemical examination. Results of the tests are reported here. A staged examination and treatment of the patient allowed the researchers to perform a correct diagnosis and obtain a satisfactory functional outcome

One-dimensional quantum chaos: Explicitly solvable cases

We present quantum graphs with remarkably regular spectral characteristics. We call them {\it regular quantum graphs}. Although regular quantum graphs are strongly chaotic in the classical limit, their quantum spectra are explicitly solvable in terms of periodic orbits. We present analytical solutions for the spectrum of regular quantum graphs in the form of explicit and exact periodic orbit expansions for each individual energy level.Comment: 9 pages and 4 figure

Distant field BHB stars and the mass of the Galaxy II: Photometry and spectroscopy of UKST candidates 16<B<19.5, 11<R<52 kpc

This is the second in a series of papers presenting a new calculation of the mass of the Galaxy based on radial velocities and distances for a sample of faint 16 < B < 21.3 field blue horizontal-branch (BHB) stars. We present accurate BV CCD photometry and spectra for 142 candidate A-type stars selected from ub_jr photometry of UK Schmidt telescope plates in six high-Galactic-latitude fields. Classification of these candidates produces a sample of 60 BHB stars at distances of 11-52 kpc from the Sun (mean 28 kpc), with heliocentric line-of-sight velocities accurate to 15 km/s, and distance errors < 10%. We provide a summary table listing coordinates and velocities of these stars. The measured dispersion of the radial component of the Galactocentric velocity for this sample is 108+-10 km/s, in agreement with a recent study of the distant halo by Sirko and coworkers. Measurements of the Ca II K line indicate that nearly all the stars are metal-poor with a mean [Fe/H] = -1.8 with dispersion 0.5. Subsequent papers will describe a second survey of BHBs to heliocentric distances 70 < R < 125 kpc and present a new estimate of the mass of the Galaxy.Comment: 16 pages, 15 figures. Accepted for publication in MNRA

Combinatorial identities for binary necklaces from exact ray-splitting trace formulae

Based on an exact trace formula for a one-dimensional ray-splitting system, we derive novel combinatorial identities for cyclic binary sequences (P\'olya necklaces).Comment: 15 page

Principal Component Analysis of SDSS Stellar Spectra

We apply Principal Component Analysis (PCA) to ~100,000 stellar spectra obtained by the Sloan Digital Sky Survey (SDSS). In order to avoid strong non-linear variation of spectra with effective temperature, the sample is binned into 0.02 mag wide intervals of the g-r color (-0.20<g-r<0.90, roughly corresponding to MK spectral types A3 to K3), and PCA is applied independently for each bin. In each color bin, the first four eigenspectra are sufficient to describe the observed spectra within the measurement noise. We discuss correlations of eigencoefficients with metallicity and gravity estimated by the Sloan Extension for Galactic Understanding and Exploration (SEGUE) Stellar Parameters Pipeline. The resulting high signal-to-noise mean spectra and the other three eigenspectra are made publicly available. These data can be used to generate high quality spectra for an arbitrary combination of effective temperature, metallicity, and gravity within the parameter space probed by the SDSS. The SDSS stellar spectroscopic database and the PCA results presented here offer a convenient method to classify new spectra, to search for unusual spectra, to train various spectral classification methods, and to synthesize accurate colors in arbitrary optical bandpasses.Comment: 25 pages, 15 figures, accepted by the Astronomical Journa

Two New Tidally Distorted White Dwarfs

We identify two new tidally distorted white dwarfs (WDs), SDSS J174140.49+652638.7 and J211921.96-001825.8 (hereafter J1741 and J2119). Both stars are extremely low mass (ELM, < 0.2 Msun) WDs in short-period, detached binary systems. High-speed photometric observations obtained at the McDonald Observatory reveal ellipsoidal variations and Doppler beaming in both systems; J1741, with a minimum companion mass of 1.1 Msun, has one of the strongest Doppler beaming signals ever observed in a binary system (0.59 \pm 0.06% amplitude). We use the observed ellipsoidal variations to constrain the radius of each WD. For J1741, the star's radius must exceed 0.074 Rsun. For J2119, the radius exceeds 0.10 Rsun. These indirect radius measurements are comparable to the radius measurements for the bloated WD companions to A-stars found by the Kepler spacecraft, and they constitute some of the largest radii inferred for any WD. Surprisingly, J1741 also appears to show a 0.23 \pm 0.06% reflection effect, and we discuss possible sources for this excess heating. Both J1741 and J2119 are strong gravitational wave sources, and the time-of-minimum of the ellipsoidal variations can be used to detect the orbital period decay. This may be possible on a timescale of a decade or less.Comment: 6 pages, 4 figures, accepted for publication in the Astrophysical Journa

Explicitly solvable cases of one-dimensional quantum chaos

We identify a set of quantum graphs with unique and precisely defined spectral properties called {\it regular quantum graphs}. Although chaotic in their classical limit with positive topological entropy, regular quantum graphs are explicitly solvable. The proof is constructive: we present exact periodic orbit expansions for individual energy levels, thus obtaining an analytical solution for the spectrum of regular quantum graphs that is complete, explicit and exact

N-body simulations with generic non-Gaussian initial conditions I: Power Spectrum and halo mass function

We address the issue of setting up generic non-Gaussian initial conditions for N-body simulations. We consider inflationary-motivated primordial non-Gaussianity where the perturbations in the Bardeen potential are given by a dominant Gaussian part plus a non-Gaussian part specified by its bispectrum. The approach we explore here is suitable for any bispectrum, i.e. it does not have to be of the so-called separable or factorizable form. The procedure of generating a non-Gaussian field with a given bispectrum (and a given power spectrum for the Gaussian component) is not univocal, and care must be taken so that higher-order corrections do not leave a too large signature on the power spectrum. This is so far a limiting factor of our approach. We then run N-body simulations for the most popular inflationary-motivated non-Gaussian shapes. The halo mass function and the non-linear power spectrum agree with theoretical analytical approximations proposed in the literature, even if they were so far developed and tested only for a particular shape (the local one). We plan to make the simulations outputs available to the community via the non-Gaussian simulations comparison project web site http://icc.ub.edu/~liciaverde/NGSCP.html.Comment: 23 pages, 10 figure