Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
bioRxiv ; 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38746371

RESUMEN

Clinical research emphasizes the implementation of rigorous and reproducible study designs that rely on between-group matching or controlling for sources of biological variation such as subject's sex and age. However, corrections for body size (i.e. height and weight) are mostly lacking in clinical neuroimaging designs. This study investigates the importance of body size parameters in their relationship with spinal cord (SC) and brain magnetic resonance imaging (MRI) metrics. Data were derived from a cosmopolitan population of 267 healthy human adults (age 30.1±6.6 years old, 125 females). We show that body height correlated strongly or moderately with brain gray matter (GM) volume, cortical GM volume, total cerebellar volume, brainstem volume, and cross-sectional area (CSA) of cervical SC white matter (CSA-WM; 0.44≤r≤0.62). In comparison, age correlated weakly with cortical GM volume, precentral GM volume, and cortical thickness (-0.21≥r≥-0.27). Body weight correlated weakly with magnetization transfer ratio in the SC WM, dorsal columns, and lateral corticospinal tracts (-0.20≥r≥-0.23). Body weight further correlated weakly with the mean diffusivity derived from diffusion tensor imaging (DTI) in SC WM (r=-0.20) and dorsal columns (-0.21), but only in males. CSA-WM correlated strongly or moderately with brain volumes (0.39≤r≤0.64), and weakly with precentral gyrus thickness and DTI-based fractional anisotropy in SC dorsal columns and SC lateral corticospinal tracts (-0.22≥r≥-0.25). Linear mixture of sex and age explained 26±10% of data variance in brain volumetry and SC CSA. The amount of explained variance increased at 33±11% when body height was added into the mixture model. Age itself explained only 2±2% of such variance. In conclusion, body size is a significant biological variable. Along with sex and age, body size should therefore be included as a mandatory variable in the design of clinical neuroimaging studies examining SC and brain structure.

2.
Front Neurol ; 15: 1341371, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38798708

RESUMEN

Degenerative cervical myelopathy (DCM) represents the final consequence of a series of degenerative changes in the cervical spine, resulting in cervical spinal canal stenosis and mechanical stress on the cervical spinal cord. This process leads to subsequent pathophysiological processes in the spinal cord tissues. The primary mechanism of injury is degenerative compression of the cervical spinal cord, detectable by magnetic resonance imaging (MRI), serving as a hallmark for diagnosing DCM. However, the relative resilience of the cervical spinal cord to mechanical compression leads to clinical-radiological discordance, i.e., some individuals may exhibit MRI findings of DCC without the clinical signs and symptoms of myelopathy. This degenerative compression of the cervical spinal cord without clinical signs of myelopathy, potentially serving as a precursor to the development of DCM, remains a somewhat controversial topic. In this review article, we elaborate on and provide commentary on the terminology, epidemiology, natural course, diagnosis, predictive value, risks, and practical management of this condition-all of which are subjects of ongoing debate.

3.
Food Microbiol ; 115: 104321, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37567631

RESUMEN

Selection of the appropriate yeast strain is one of the most crucial steps in a brewery. Traditionally, yeast strain's abilities during beer fermentation are described according to brewer's experiences. Hence, these descriptions could be inaccurate and strictly based on sensory experiences. In this study, lager beers fermented by four traditional bottom-fermented yeast strains were characterized in detail by sensomic approach. The obtained results revealed that yeast strains can influence most of the sensory-related components in beer, not only esters and higher alcohols, but also carbonyls, amino acids, saccharides, fatty acids, heterocyclic compounds, hop oils, and other hop-related components. By comparison of chemical and sensory characteristics of each studied beer, the theoretical importance of sensory interactions on beer flavor perception was also revealed as the general conception that the beers with similar flavors have also similar chemical profiles (and vice versa) was seemed as not valid.


Asunto(s)
Saccharomyces cerevisiae , Saccharomyces , Saccharomyces cerevisiae/metabolismo , Cerveza/análisis , Saccharomyces/metabolismo , Fermentación
4.
Biomed Opt Express ; 14(6): 2689-2708, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37342686

RESUMEN

Solid tumor metastases cause most cancer-related deaths. The prevention of their occurrence misses suitable anti-metastases medicines newly labeled as migrastatics. The first indication of migrastatics potential is based on an inhibition of in vitro enhanced migration of tumor cell lines. Therefore, we decided to develop a rapid test for qualifying the expected migrastatic potential of some drugs for repurposing. The chosen Q-PHASE holographic microscope provides reliable multifield time-lapse recording and simultaneous analysis of the cell morphology, migration, and growth. The results of the pilot assessment of the migrastatic potential exerted by the chosen medicines on selected cell lines are presented.

5.
Quant Imaging Med Surg ; 12(4): 2261-2279, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35371944

RESUMEN

Background: Degenerative cervical spinal cord compression is becoming increasingly prevalent, yet the MRI criteria that define compression are vague, and vary between studies. This contribution addresses the detection of compression by means of the Spinal Cord Toolbox (SCT) and assesses the variability of the morphometric parameters extracted with it. Methods: Prospective cross-sectional study. Two types of MRI examination, 3 and 1.5 T, were performed on 66 healthy controls and 118 participants with cervical spinal cord compression. Morphometric parameters from 3T MRI obtained by Spinal Cord Toolbox (cross-sectional area, solidity, compressive ratio, torsion) were combined in multivariate logistic regression models with the outcome (binary dependent variable) being the presence of compression determined by two radiologists. Inter-trial (between 3 and 1.5 T) and inter-rater (three expert raters and SCT) variability of morphometric parameters were assessed in a subset of 35 controls and 30 participants with compression. Results: The logistic model combining compressive ratio, cross-sectional area, solidity, torsion and one binary indicator, whether or not the compression was set at level C6/7, demonstrated outstanding compression detection (area under curve =0.947). The single best cut-off for predicted probability calculated using a multiple regression equation was 0.451, with a sensitivity of 87.3% and a specificity of 90.2%. The inter-trial variability was better in Spinal Cord Toolbox (intraclass correlation coefficient was 0.858 for compressive ratio and 0.735 for cross-sectional area) compared to expert raters (mean coefficient for three expert raters was 0.722 for compressive ratio and 0.486 for cross-sectional area). The analysis of inter-rater variability demonstrated general agreement between SCT and three expert raters, as the correlations between SCT and raters were generally similar to those of the raters between one another. Conclusions: This study demonstrates successful semi-automated compression detection based on four parameters. The inter-trial variability of parameters established through two MRI examinations was conclusively better for Spinal Cord Toolbox compared with that of three experts' manual ratings.

8.
Sci Data ; 8(1): 219, 2021 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-34400655

RESUMEN

In a companion paper by Cohen-Adad et al. we introduce the spine generic quantitative MRI protocol that provides valuable metrics for assessing spinal cord macrostructural and microstructural integrity. This protocol was used to acquire a single subject dataset across 19 centers and a multi-subject dataset across 42 centers (for a total of 260 participants), spanning the three main MRI manufacturers: GE, Philips and Siemens. Both datasets are publicly available via git-annex. Data were analysed using the Spinal Cord Toolbox to produce normative values as well as inter/intra-site and inter/intra-manufacturer statistics. Reproducibility for the spine generic protocol was high across sites and manufacturers, with an average inter-site coefficient of variation of less than 5% for all the metrics. Full documentation and results can be found at https://spine-generic.rtfd.io/ . The datasets and analysis pipeline will help pave the way towards accessible and reproducible quantitative MRI in the spinal cord.


Asunto(s)
Imagen por Resonancia Magnética , Neuroimagen , Médula Espinal/diagnóstico por imagen , Médula Espinal/ultraestructura , Adulto , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Reproducibilidad de los Resultados
9.
Nat Protoc ; 16(10): 4611-4632, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34400839

RESUMEN

Quantitative spinal cord (SC) magnetic resonance imaging (MRI) presents many challenges, including a lack of standardized imaging protocols. Here we present a prospectively harmonized quantitative MRI protocol, which we refer to as the spine generic protocol, for users of 3T MRI systems from the three main manufacturers: GE, Philips and Siemens. The protocol provides guidance for assessing SC macrostructural and microstructural integrity: T1-weighted and T2-weighted imaging for SC cross-sectional area computation, multi-echo gradient echo for gray matter cross-sectional area, and magnetization transfer and diffusion weighted imaging for assessing white matter microstructure. In a companion paper from the same authors, the spine generic protocol was used to acquire data across 42 centers in 260 healthy subjects. The key details of the spine generic protocol are also available in an open-access document that can be found at https://github.com/spine-generic/protocols . The protocol will serve as a starting point for researchers and clinicians implementing new SC imaging initiatives so that, in the future, inclusion of the SC in neuroimaging protocols will be more common. The protocol could be implemented by any trained MR technician or by a researcher/clinician familiar with MRI acquisition.


Asunto(s)
Imagen por Resonancia Magnética , Neuroimagen , Médula Espinal , Adulto , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino
10.
J Neurotrauma ; 38(21): 2999-3010, 2021 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-34428934

RESUMEN

Degenerative cervical myelopathy (DCM) is a severe consequence of degenerative cervical spinal cord (CSC) compression. The non-myelopathic stage of compression (NMDC) is highly prevalent and often progresses to disabling DCM. This study aims to disclose markers of progressive neurochemical alterations in NMDC and DCM by utilizing an approach based on state-of-the-art proton magnetic resonance spectroscopy (1H-MRS). Proton-MRS data were prospectively acquired from 73 participants with CSC compression and 47 healthy controls (HCs). The MRS voxel was centered at the C2 level. Compression-affected participants were clinically categorized as NMDC and DCM, radiologically as mild (MC) or severe (SC) compression. CSC volumes and neurochemical concentrations were compared between cohorts (HC vs. NMDC vs. DCM and HC vs. MC vs. SC) with general linear models adjusted for age and height (pFWE < 0.05) and correlated to stenosis severity, electrophysiology, and myelopathy symptoms (p < 0.05). Whereas the ratio of total creatine (tCr) to total N-acetylaspartate (tNAA) increased in NMDC (+11%) and in DCM (+26%) and SC (+21%), myo-inositol/tNAA, glutamate + glutamine/tNAA, and volumes changed only in DCM (+20%, +73%, and -14%) and SC (+12%, +46%, and -8%, respectively) relative to HCs. Both tCr/tNAA and myo-inositol/tNAA correlated with compression severity and volume (-0.376 < r < -0.259). Myo-inositol/tNAA correlated with myelopathy symptoms (r = -0.670), whereas CSC volume did not. Short-echo 1H-MRS provided neurochemical signatures of CSC impairment that reflected compression severity and clinical significance. Whereas volumetry only reflected clinically manifest myelopathy (DCM), MRS detected neurochemical changes already before the onset of myelopathy symptoms.


Asunto(s)
Médula Cervical , Espectroscopía de Resonancia Magnética , Compresión de la Médula Espinal/metabolismo , Compresión de la Médula Espinal/patología , Adulto , Anciano , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Estudios de Casos y Controles , Vértebras Cervicales , Creatina/metabolismo , Femenino , Ácido Glutámico/metabolismo , Humanos , Inositol/metabolismo , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad
11.
Eur J Neurol ; 28(11): 3784-3797, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34288268

RESUMEN

BACKGROUND AND PURPOSE: Non-myelopathic degenerative cervical spinal cord compression (NMDC) frequently occurs throughout aging and may progress to potentially irreversible degenerative cervical myelopathy (DCM). Whereas standard clinical magnetic resonance imaging (MRI) and electrophysiological measures assess compression severity and neurological dysfunction, respectively, underlying microstructural deficits still have to be established in NMDC and DCM patients. The study aims to establish tract-specific diffusion MRI markers of electrophysiological deficits to predict the progression of asymptomatic NMDC to symptomatic DCM. METHODS: High-resolution 3 T diffusion MRI was acquired for 103 NMDC and 21 DCM patients compared to 60 healthy controls to reveal diffusion alterations and relationships between tract-specific diffusion metrics and corresponding electrophysiological measures and compression severity. Relationship between the degree of DCM disability, assessed by the modified Japanese Orthopaedic Association scale, and tract-specific microstructural changes in DCM patients was also explored. RESULTS: The study identified diffusion-derived abnormalities in the gray matter, dorsal and lateral tracts congruent with trans-synaptic degeneration and demyelination in chronic degenerative spinal cord compression with more profound alterations in DCM than NMDC. Diffusion metrics were affected in the C3-6 area as well as above the compression level at C3 with more profound rostral deficits in DCM than NMDC. Alterations in lateral motor and dorsal sensory tracts correlated with motor and sensory evoked potentials, respectively, whereas electromyography outcomes corresponded with gray matter microstructure. DCM disability corresponded with microstructure alteration in lateral columns. CONCLUSIONS: Outcomes imply the necessity of high-resolution tract-specific diffusion MRI for monitoring degenerative spinal pathology in longitudinal studies.


Asunto(s)
Compresión de la Médula Espinal , Enfermedades de la Médula Espinal , Vértebras Cervicales/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética , Humanos , Imagen por Resonancia Magnética , Médula Espinal/diagnóstico por imagen , Compresión de la Médula Espinal/diagnóstico por imagen
12.
Sci Rep ; 10(1): 17529, 2020 10 16.
Artículo en Inglés | MEDLINE | ID: mdl-33067520

RESUMEN

Diffusion magnetic resonance imaging (dMRI) proved promising in patients with non-myelopathic degenerative cervical cord compression (NMDCCC), i.e., without clinically manifested myelopathy. Aim of the study is to present a fast multi-shell HARDI-ZOOMit dMRI protocol and validate its usability to detect microstructural myelopathy in NMDCCC patients. In 7 young healthy volunteers, 13 age-comparable healthy controls, 18 patients with mild NMDCCC and 15 patients with severe NMDCCC, the protocol provided higher signal-to-noise ratio, enhanced visualization of white/gray matter structures in microstructural maps, improved dMRI metric reproducibility, preserved sensitivity (SE = 87.88%) and increased specificity (SP = 92.31%) of control-patient group differences when compared to DTI-RESOLVE protocol (SE = 87.88%, SP = 76.92%). Of the 56 tested microstructural parameters, HARDI-ZOOMit yielded significant patient-control differences in 19 parameters, whereas in DTI-RESOLVE data, differences were observed in 10 parameters, with mostly lower robustness. Novel marker the white-gray matter diffusivity gradient demonstrated the highest separation. HARDI-ZOOMit protocol detected larger number of crossing fibers (5-15% of voxels) with physiologically plausible orientations than DTI-RESOLVE protocol (0-8% of voxels). Crossings were detected in areas of dorsal horns and anterior white commissure. HARDI-ZOOMit protocol proved to be a sensitive and practical tool for clinical quantitative spinal cord imaging.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Compresión de la Médula Espinal/patología , Enfermedades de la Médula Espinal/patología , Adulto , Ingeniería Biomédica , Estudios de Casos y Controles , Vértebras Cervicales/patología , Análisis por Conglomerados , Imagen de Difusión Tensora , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Relación Señal-Ruido , Compresión de la Médula Espinal/diagnóstico por imagen , Enfermedades de la Médula Espinal/diagnóstico por imagen
13.
Neuromuscul Disord ; 30(5): 427-430, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32312586

RESUMEN

We report the case of a patient suffering from duplicity of myotonic dystrophy type 1 and ulcerative colitis whose treatment for ulcerative colitis included repeated administrations of descending doses of methylprednisolone and in whom we found an association between methylprednisolone dosing and cessation of myotonia. Myotonia severity was expressed as relaxation time after voluntary contraction and as a patient-reported outcome using the Czech version of the Myotonia Behavior Scale. The patient was being treated for a flare of ulcerative colitis, starting with 32 mg of methylprednisolone and reducing the dose by 4 mg a week. The symptoms of myotonia began to wear off three weeks after starting methylprednisolone and had totally disappeared by four weeks after starting methylprednisolone. The first symptoms of myotonia returned about a month after the last dose of methylprednisolone and reached a peak of severity more than two months after the final dose.


Asunto(s)
Corticoesteroides/administración & dosificación , Metilprednisolona/administración & dosificación , Miotonía/tratamiento farmacológico , Distrofia Miotónica/tratamiento farmacológico , Adulto , Colitis Ulcerosa/tratamiento farmacológico , Femenino , Humanos
14.
J Air Transp Manag ; 75: 27-38, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32572324

RESUMEN

Air travelers can carry an infectious disease's pathogenic microorganism in their bodies and spread the disease from one country to another in a few days. To delay the spread, health screening stations may be set up at airport terminals to screen travelers. This research tested three different health screening strategies, each with a different combination of screening stations at trip origins, destinations and connecting airports. Discrete event simulations were performed, based on the 2014 to 2016 Ebola virus epidemic, with special focus on travelers from the West African countries traveling to the United States, including travelers who transferred flights at airports in European Union member states. The effectiveness of the screening strategies was analyzed in terms of correct detection, missed detection and false alarm rate. The results showed that exit screening at trip origins brought big improvements in the performance measurements compared to no screening. However, additional screening at the destinations and connecting airports contributed marginal benefits.

15.
Muscle Nerve ; 59(4): 431-435, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30575988

RESUMEN

INTRODUCTION: The objective of this study was to develop a simple method for quantitative assessment of myotonia in patients with myotonic dystrophy type 1 (DM1) and DM2, to compare the myotonia severity, and to correlate this objective outcome with a subjective scale, the Myotonia Behaviour Scale (MBS). METHODS: A commercially available dynamometer was used for all measurements. The relaxation time after voluntary contraction was measured in 20 patients with DM1, 25 patients with DM2, and 35 healthy controls. RESULTS: The average relaxation time was 0.17 s in controls, 2.96 s in patients with DM1, and 0.4 s in patients with DM2. The correlation between relaxation time and MBS score was significant, 0.627 in patients with DM1 and 0.581 in patients with DM2. DISCUSSION: Our method provides a valid and reliable quantitative measure of grip myotonia suitable as an outcome measure in clinical trials and as part of routine examinations to gather data on the natural history of myotonic disorders. Muscle Nerve 59:431-435, 2019.


Asunto(s)
Dinamómetro de Fuerza Muscular , Miotonía/diagnóstico , Distrofia Miotónica/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Conducta , Femenino , Fuerza de la Mano , Humanos , Masculino , Persona de Mediana Edad , Contracción Muscular , Relajación Muscular , Fuerza Muscular , Miotonía/fisiopatología , Distrofia Miotónica/fisiopatología , Distrofia Miotónica/psicología , Reproducibilidad de los Resultados , Adulto Joven
16.
J Agric Food Chem ; 61(51): 12670-5, 2013 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-24308508

RESUMEN

The rate of beer aging is affected by storage conditions including largely time and temperature. Although bottled beer is commonly stored for up to 1 year, sensorial damage of it is quite frequent. Therefore, a method for retrospective determination of temperature of stored beer was developed. The method is based on the determination of selected carbonyl compounds called as "aging indicators", which are formed during beer aging. The aging indicators were determined using GC-MS after precolumn derivatization with O-(2,3,4,5,6-pentaflourobenzyl)hydroxylamine hydrochloride, and their profile was correlated with the development of old flavor evolving under defined conditions (temperature, time) using both a mathematical and statistical apparatus. Three approaches, including calculation from regression graph, multiple linear regression, and neural networks, were employed. The ultimate uncertainty of the method ranged from 3.0 to 11.0 °C depending on the approach used. Furthermore, the assay was extended to include prediction of beer tendency to sensory aging from freshly bottled beer.


Asunto(s)
Cerveza/análisis , Aromatizantes/análisis , Cromatografía de Gases y Espectrometría de Masas/métodos , Gusto , Almacenamiento de Alimentos , Humanos , Temperatura , Factores de Tiempo
17.
J Agric Food Chem ; 57(23): 11081-5, 2009 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-19904941

RESUMEN

Solid-phase extraction (SPE), solid-phase microextraction (SPME) using carbowax/divinylbenzen fiber, and stir bar sorptive extraction (SBSE) followed by solvent back extraction have been used for the extraction of free fatty acids (caproic, caprylic, pelargonic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, and linolenic acids) from beer. Subsequent gas chromatographic analyses with flame ionization detection were used for the determination of these compounds. Medium-chain fatty acids (caproic-lauric acid) were determined as free acids, and long-chain fatty acids (myristic-linolenic acids) were determined as methyl esters after methylation by BF(3)-methanol 14%. Linearity, recovery, and repeatability of all methods have been determined and compared with the SPE method used as a reference (SPME method was used only for medium-chain fatty acid determination). All three procedures provide similar working parameters characterized by high repeatability (2.3-16.3%) and good linearity (correlation coefficient ranging from 0.9919 to 0.9999). Results of beer analyses obtained by using these three methods were highly correlated. Although all methods provide compatible alternatives, for medium-chain fatty acid analysis SPME may be a more appropriate technique due to its operational simplicity, repeatability, and low cost.


Asunto(s)
Cerveza/análisis , Ácidos Grasos/análisis , Extracción en Fase Sólida/métodos , Cromatografía de Gases , Extracción en Fase Sólida/instrumentación , Microextracción en Fase Sólida/instrumentación , Microextracción en Fase Sólida/métodos
18.
J Chromatogr A ; 1196-1197: 96-9, 2008 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-18508065

RESUMEN

Free medium-chain fatty acids in beer originate from raw materials, mainly from the fermentation activity of yeasts, and can influence beer taste, vitality of yeasts and also the foam stability of beer. This study presents the development of the method for the determination of free fatty medium-chain acids including caproic acid, caprylic acid, capric acid and lauric acid in beer or wort using stir bar sorptive extraction (SBSE). The combination of this extraction technique with solvent back extraction of the extracted analytes and subsequent gas chromatographic analysis with flame ionization detection was used for the determination of these compounds. The influences of different solvent back solutions, sampling time, solvent back extraction times and different contents of ethanol were studied. The method had high repeatability (RSD <6.7%), good linearity (the correlation coefficients were higher than 0.9963 for quadratic curves over the concentration range 0.5-8.0mg/l) and recoveries 57-89%.


Asunto(s)
Cerveza/análisis , Fraccionamiento Químico/métodos , Ácidos Grasos/análisis , Caproatos/análisis , Caprilatos/análisis , Cromatografía de Gases , Ácidos Decanoicos/análisis , Ácidos Grasos/química , Ácidos Láuricos/análisis , Reproducibilidad de los Resultados , Solventes/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...