131 research outputs found
Generalized Net Model of Muscle Pain Diagnosing
Pain is the most common symptom of the many musculoskeletal pathologies. Musculoskeletal pain affects the muscles, ligaments, tendons, nerves and bones and might be caused by diverse factors. Musculoskeletal pain ranges from mild to severe. It can be local or diffuse, and acute or chronic. Due to the wide range of conditions that may cause such a symptom, diagnosing process is challenging and a systematic approach is necessary. In this investigation we present a successful example of generalized nets application in medical diagnosing and propose a novel approach leading to the appropriate diagnostic considerations. The method proposed in this investigation accurately identifies the various steps during the muscle pain diagnosing process and significantly improves the health care level. Obtained so far results could be used to assist in the decision making in the diagnostic processes
Modulated optical reflectance measurements on La2/3Sr1/3MnO3 thin films
The modulated optical reflectance (MOR) measurement technique was applied to
colossal magnetoresistive materials, in particular, La2/3Sr1/3MnO3 (LSMO) thin
films. The contactless measurement scheme is prospective for many applications
spanning from materials characterization to new devices like reading heads for
magnetically recorded media. A contrasted room temperature surface scan of a
100 microns wide 400 microns long bridge patterned into LSMO film provided
preliminary information about the film homogeneity. Then the temperature was
varied between 240 and 400 K, i.e. through the ferromagnetic to paramagnetic
transition. A clear relation between the MOR signal measured as function of the
temperature and the relative derivative of the resistivity up to the Curie
temperature was observed. This relationship is fundamental for the MOR
technique and its mechanism was explored in the particular case of LSMO.
Analysis in the framework of the Drude model showed that, within certain
conditions, the measured MOR signal changes are correlated to changes in the
charge carrier concentration.Comment: 29 pages, accepted for publication in J. Appl. Phy
In vitro and in silico studies of the membrane permeability of natural flavonoids from Silybum marianum (L.) Gaertn. and their derivatives
Background: In recent years the number of natural products used as pharmaceuticals, components of dietary supplements and cosmetics has increased tremendously requiring more extensive evaluation of their pharmacokinetic properties.
Purpose: This study aims at combining in vitro and in silico methods to evaluate the gastrointestinal absorption (GIA) of natural flavonolignans from milk thistle (Silybum marianum (L.) Gaertn.) and their derivatives.
Methods: A parallel artificial membrane permeability assay (PAMPA) was used to evaluate the transcellular permeability of the plant main components. A dataset of 269 compounds with measured PAMPA values and specialized software tools for calculating molecular descriptors were utilized to develop a quantitative structure-activity relationship (QSAR) model to predict PAMPA permeability.
Results: The PAMPA permeabilities of 7 compounds constituting the main components of the milk thistle were measured and their GIA was evaluated. A freely-available and easy to use QSAR model predicting PAMPA permeability from calculated physico-chemical molecular descriptors was derived and validated on an external dataset of 783 compounds with known GIA. The predicted permeability values correlated well with obtained in vitro results. The QSAR model was further applied to predict the GIA of 31 experimentally untested flavonolignans.
Conclusions: According to both in vitro and in silico results most flavonolignans are highly permeable in the gastrointestinal tract, which is a prerequisite for sufficient bioavailability and use as lead structures in drug development. The combined in vitro/in silico approach can be used for the preliminary evaluation of GIA and to guide further laboratory experiments on pharmacokinetic characterization of bioactive compounds, including natural products
Advances in the Prediction of Gastrointestinal Absorption: Quantitative Structure-Activity Relationship (QSAR) modelling of PAMPA Permeability
Gastrointestinal absorption (GI absorption) is a key absorption, distribution, metabolism, and excretion (ADME) property when the biological effects of substances are evaluated. The Parallel Artificial Membrane Permeability Assay (PAMPA) has emerged as a primary screen for determining passive transcellular permeability, the dominant GI absorption mechanism for many drugs, thus helping with the prioritisation of the most promising lead compounds for pharmacokinetic studies. Recently the PAMPA assay has attracted increasing interest from various other industrial sectors, including cosmetics, where such non-animal models may provide a crucial source of information for in vitro - in vivo extrapolation. This method is also a reliable source of experimental data for Quantitative Structure-Activity Relationship (QSAR) modelling of GI absorption. In this investigation, published QSAR models for PAMPA were reviewed with the aim to summarise and assess critically the current state of the art. The review indicates a relatively small number of QSARs compared to some endpoints, but much consistency within the models. PAMPA permeability increases with hydrophobicity and decreases with the surface area occupied by hydrogen bond acceptor/donor atoms. The models can be applied to screening for bioactive compounds with the potential to pass the gastrointestinal barrier as well as to design new structures with increased PAMPA permeability, thus with better expectations towards improved in vivo GI absorption
Cognitive Impairment and Affective Disorders in Patients With Obstructive Sleep Apnea Syndrome
Sleep-related breathing disorders could be accompanied by or caused by a variety of medical conditions. They are considered to be a significant medical and social problem. Together with excessive daytime sleepiness, patients with obstructive sleep apnea experience neuropsychological symptoms such as anxiety, attention deficits, cognitive impairment, depressive symptoms and other psychological disturbances leading to social adjustment difficulties. Patients diagnosed with obstructive sleep apnea demonstrate a decline in a wide spectrum of cognitive abilities, including memory, attention, psychomotor speed, executive, verbal and visual-spatial skills. The aim of this study is to investigate the cognitive functioning and affective disorders among patients with obstructive sleep apnea syndrome and to examine the frequency and severity of cases in comparison with a control group consisting of healthy volunteers. Our research has shown that there is a relation between sleep apnea and cognitive impairments and affective changes. This relation can be explained by the direct effect of the syndrome on the patient, where the main connecting factor is the severity and the distribution of excessive daytime sleepiness. Along with treatment of the somatic medical condition, it is extremely important that the patient's mental state is treated as well.Trial Registration: 57/2013, Medical University - Sofia, Bulgaria
Stroke in urban and rural populations in north-east Bulgaria: incidence and case fatality findings from a 'hot pursuit' study
BACKGROUND: Bulgaria's official stroke mortality rates are higher for rural than urban areas. Official mortality data has indicated that these rates are amongst the highest in Europe. There has been a lack of studies measuring stroke incidence in urban and rural populations. METHODS: We established intensive notification networks covering 37791 residents in Varna city and 18656 residents (55% of them village-dwellers), all aged 45 to 84, in 2 rural districts. From May 1, 2000 to April 30, 2001 frequent contact was maintained with notifiers and death registrations were scanned regularly. Suspected incident strokes were assessed by study neurologists within a median of 8 days from onset. RESULTS: 742 events were referred for neurological assessment and 351 of these, which met the WHO criteria for stroke, were in persons aged 45 to 84 and were first ever in a lifetime. Incidence rates, standardised using the world standard weights for ages 45 to 84, were 909 (/100000/year) (95% CI 712–1105) and 597 (482–712) for rural and urban males and 667 (515–818) and 322 (248–395) for rural and urban females. Less than half were admitted to hospital (15% among rural females over 65). Twenty-eight day case fatality was 35% (123/351) overall and 48% (46/96) in village residents. The excess case fatality in the villages could not be explained by age or severity. CONCLUSIONS: Rural incidence rates were over twice those reported for western populations but the rate for urban females was similar to other western rates. The high level and marked heterogeneity in both stroke incidence and case fatality merit further investigation
Resurrection and redescription of Varestrongylus alces (Nematoda; Protostrongylidae), a lungworm of the Eurasian moose (Alces alces), with report on associated pathology
Varestrongylus alces, a lungworm in Eurasian moose from Europe has been considered a
junior synonym of Varestrongylus capreoli, in European roe deer, due to a poorly detailed
morphological description and the absence of a type-series.
Methods
Specimens used in the redescription were collected from lesions in the lungs of Eurasian
moose, from Vestby, Norway. Specimens were described based on comparative morphology
and integrated approaches. Molecular identification was based on PCR, cloning and
sequencing of the ITS-2 region of the nuclear ribosomal DNA. Phylogenetic analysis
compared V. alces ITS-2 sequences to these of other Varestrongylus species and other
protostrongylids.
Results
Varestrongylus alces is resurrected for protostrongylid nematodes of Eurasian moose from
Europe. Varestrongylus alces causes firm nodular lesions that are clearly differentiated from
the adjacent lung tissue. Histologically, lesions are restricted to the parenchyma with adult,
egg and larval parasites surrounded by multinucleated giant cells, macrophages, eosinophilic
granulocytes, lymphocytes. The species is valid and distinct from others referred to
Varestrongylus, and should be separated from V. capreoli. Morphologically, V. alces can be
distinguished from other species by characters in the males that include a distally bifurcated
gubernaculum, arched denticulate crura, spicules that are equal in length and relatively short,
and a dorsal ray that is elongate and bifurcated. Females have a well-developed provagina,
and are very similar to those of V. capreoli. Morphometrics of first-stage larvae largely
overlap with those of other Varestrongylus. Sequences of the ITS-2 region strongly support
mutual independence of V. alces, V. cf. capreoli, and the yet undescribed species of
Varestrongylus from North American ungulates. These three taxa form a well-supported
crown-clade as the putative sister of V. alpenae. The association of V. alces and Alces or its
ancestors is discussed in light of host and parasite phylogeny and host historical
biogeography.
Varestrongylus alces is a valid species, and should be considered distinct from V. capreoli.
Phylogenetic relationships among Varestrongylus spp. from Eurasia and North America are
complex and consistent with faunal assembly involving recurrent events of geographic
expansion, host switching and subsequent speciation.
Cervidae, Cryptic species, Historical biogeography, ITS-2, Metastrongyloidea, Parasite
biodiversity, Varestrongylinae, Varestrongylus capreoli, Verminous pneumoniapublishedVersio
Open Babel: An open chemical toolbox
Background: A frequent problem in computational modeling is the interconversion of chemical structures between different formats. While standard interchange formats exist (for example, Chemical Markup Language) and de facto standards have arisen (for example, SMILES format), the need to interconvert formats is a continuing problem due to the multitude of different application areas for chemistry data, differences in the data stored by different formats (0D versus 3D, for example), and competition between software along with a lack of vendorneutral formats. Results: We discuss, for the first time, Open Babel, an open-source chemical toolbox that speaks the many languages of chemical data. Open Babel version 2.3 interconverts over 110 formats. The need to represent such a wide variety of chemical and molecular data requires a library that implements a wide range of cheminformatics algorithms, from partial charge assignment and aromaticity detection, to bond order perception and canonicalization. We detail the implementation of Open Babel, describe key advances in the 2.3 release, and outline a variety of uses both in terms of software products and scientific research, including applications far beyond simple format interconversion. Conclusions: Open Babel presents a solution to the proliferation of multiple chemical file formats. In addition, it provides a variety of useful utilities from conformer searching and 2D depiction, to filtering, batch conversion, and substructure and similarity searching. For developers, it can be used as a programming library to handle chemical data in areas such as organic chemistry, drug design, materials science, and computational chemistry. It is freely available under an open-source license fro
Preclinical Models of Brain Metastasis
Research at the Brain Metastasis Group is supported by MINECO grants MINECO-Retos SAF2017-89643-R (M.V.), Bristol-Myers Squibb- Melanoma Research Alliance Young Investigator Award 2017 (498103) (M.V.), Beug Foundation’s Prize for Metastasis Research 2017 (M.V.), Fundación Ramón
Areces (CIVP19S8163) (M.V.), Worldwide Cancer Research (19-0177) (M.V.), H2020-FETOPEN (828972)N
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