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

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

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

Prognostic factors of intracranial purulent-septic complications of combat-related gunshot penetrating skull and brain wounds.

Purpose – to ana­lyze the structure of intracranial purulent-septic complications (IPSC), determine the factors influencing development of purulent-septic complications in patients with combat-related gunshot penetrating skull and brain wounds (CRPSBW), determine the effect of intracranial PSC on patients’ outcomes. A prospective analysis of results of exa­mination and treatment of 121 patients was performed. All patients had gunshot penetrating skull and brain wounds sustained in combat conditions during a local armed conflict in the Eastern Ukraine. Evaluation of treatment outcome included analysis of mortality in 1 month (survived/died) and dichotomous Glasgow Outcome Scale (GOS) score in 12 months (favorable/unfavorable outcome). 121 wounded men aged 18 to 56 (average, 34.1±9.1) were included in the study. Intracranial purulent-septic complications (IPSC) were diagnosed in 14 (11.6%) gunshot CRPSBW patients. The following prognostic factors had statistically significantly correlation with the risk of intracranial purulent-septic complications development: wound liquorrhea on admission (p = 0.043), intraventricular hemorrhage (p = 0.007), bone fragments left in the wound (p = 0.0152), and  duration of inflow-outflow wound drainage for more than 3 days (p= 0.0123). Intracranial PSC patients had mortality rate of 50%, and only 14.3% of those patients had a favorable outcome according to GOS score in one year. Presence of intracranial PSC had statistically significant association with mortality rate (p=0.0091) and GOS score in one year (p=0.0001)

Spectroscopy of Bright QUEST RR Lyrae Stars: Velocity Substructures toward Virgo

Using a sample of 43 bright (V<16.1, distance <13 kpc) RR Lyrae stars (RRLS) from the QUEST survey with spectroscopic radial velocities and metallicities, we find that several separate halo substructures contribute to the Virgo overdensity (VOD). While there is little evidence for halo substructure in the spatial distribution of these stars, their distribution in radial velocity reveals two moving groups. These results are reinforced when the sample is combined with a sample of blue horizontal branch stars that were identified in the SDSS, and the combined sample provides evidence for one additional moving group. These groups correspond to peaks in the radial velocity distribution of a sample of F type main-sequence stars that was recently observed in the same directon by SEGUE, although in one case the RRLS and F star groups may not lie at the same distance. One of the new substructures has a very narrow range in metallicity, which is more consistent with it being the debris from a destroyed globular cluster than from a dwarf galaxy. A small concentration of stars have radial velocities that are similar to the Virgo Stellar Stream (VSS) that was identified previously in a fainter sample of RRLS. Our results suggest that this feature extends to distances as short as ~12 kpc from its previous detection at ~19 kpc. None of the new groups and only one star in the sample have velocities that are consistent with membership in the leading tidal stream from the Sagittarius Dwarf Spheroidal Galaxy, which some authors have suggested is the origin of the VOD.Comment: Accepted for publication in the A

Changes in the proliferative program limit astrocyte homeostasis in the aged post-traumatic murine cerebral cortex

Aging leads to adverse outcomes after traumatic brain injury. The mechanisms underlying these defects, however, are not yet clear. In this study, we found that astrocytes in the aged post-traumatic cerebral cortex develop a significantly reduced proliferative response, resulting in reduced astrocyte numbers in the penumbra. Moreover, experiments of reactive astrocytes in vitro reveal that their diminished proliferation is due to an age-related switch in the division mode with reduced cell-cycle re-entry rather than changes in cell-cycle length. Notably, reactive astrocytes in vivo and in vitro become refractory to stimuli increasing their proliferation during aging, such as Sonic hedgehog signaling. These data demonstrate for the first time that age-dependent, most likely intrinsic changes in the proliferative program of reactive astrocytes result in their severely hampered proliferative response to traumatic injury thereby affecting astrocyte homeostasis.Instituto de Biotecnologia y Biologia Molecula

Photometric identification of blue horizontal branch stars

We investigate the performance of some common machine learning techniques in identifying BHB stars from photometric data. To train the machine learning algorithms, we use previously published spectroscopic identifications of BHB stars from SDSS data. We investigate the performance of three different techniques, namely k nearest neighbour classification, kernel density estimation and a support vector machine (SVM). We discuss the performance of the methods in terms of both completeness and contamination. We discuss the prospect of trading off these values, achieving lower contamination at the expense of lower completeness, by adjusting probability thresholds for the classification. We also discuss the role of prior probabilities in the classification performance, and we assess via simulations the reliability of the dataset used for training. Overall it seems that no-prior gives the best completeness, but adopting a prior lowers the contamination. We find that the SVM generally delivers the lowest contamination for a given level of completeness, and so is our method of choice. Finally, we classify a large sample of SDSS DR7 photometry using the SVM trained on the spectroscopic sample. We identify 27,074 probable BHB stars out of a sample of 294,652 stars. We derive photometric parallaxes and demonstrate that our results are reasonable by comparing to known distances for a selection of globular clusters. We attach our classifications, including probabilities, as an electronic table, so that they can be used either directly as a BHB star catalogue, or as priors to a spectroscopic or other classification method. We also provide our final models so that they can be directly applied to new data.Comment: To appear in A&A. 19 pages, 22 figures. Tables 7, A3 and A4 available electronically onlin

Experimental simulation of quantum graphs by microwave networks

We present the results of experimental and theoretical study of irregular, tetrahedral microwave networks consisting of coaxial cables (annular waveguides) connected by T-joints. The spectra of the networks were measured in the frequency range 0.0001-16 GHz in order to obtain their statistical properties such as the integrated nearest neighbor spacing distribution and the spectral rigidity. The comparison of our experimental and theoretical results shows that microwave networks can simulate quantum graphs with time reversal symmetry. In particular, we use the spectra of the microwave networks to study the periodic orbits of the simulated quantum graphs. We also present experimental study of directional microwave networks consisting of coaxial cables and Faraday isolators for which the time reversal symmetry is broken. In this case our experimental results indicate that spectral statistics of directional microwave networks deviate from predictions of Gaussian orthogonal ensembles (GOE) in random matrix theory approaching, especially for small eigenfrequency spacing s, results for Gaussian unitary ensembles (GUE). Experimental results are supported by the theoretical analysis of directional graphs.Comment: 16 pages, 7 figures, to be published in Phys. Rev.