grey relational analysis
Dotaz
Zobrazit nápovědu
Background: Iron accumulates in brain tissue in healthy subjects during aging. Our goal was to conduct a detailed analysis of iron deposition patterns in the cerebral deep grey matter and cortex using region-based and whole-brain analyses of brain magnetic susceptibility. Methods: Brain MRI was performed in 95 healthy individuals aged between 21 and 58 years on a 3T scanner. MRI protocol included T1-weighted (T1W) magnetization-prepared rapid acquisition with gradient echo images and 3D flow-compensated multi-echo gradient-echo images for quantitative susceptibility mapping (QSM). In the region-based analysis, QSM and T1W images entered an automated multi-atlas segmentation pipeline and regional mean bulk susceptibility values were calculated. The whole-brain analysis included a non-linear transformation of QSM images to the standard MNI template. For the whole-brain analysis voxel-wise maps of linear regression slopes β and P values were calculated. Regional masks of cortical voxels with a significant association between susceptibility and age were created and further analyzed. Results: In cortical regions, the highest increase of susceptibility values with age was found in areas involved in motor functions (precentral and postcentral areas, premotor cortex), in cognitive processing (prefrontal cortex, superior temporal gyrus, insula, precuneus), and visual processing (occipital gyri, cuneus, posterior cingulum, fusiform, calcarine and lingual gyrus). Thalamic susceptibility increased until the fourth decade and decreased thereafter with the exception of the pulvinar where susceptibility increase was observed throughout the adult lifespan. Deep grey matter structures with the highest increase of susceptibility values with age included the red nucleus, putamen, substantia nigra, dentate nucleus, external globus pallidus, caudate nucleus, and the subthalamic nucleus in decreasing order. Conclusions: Accumulation of iron in basal ganglia follows a linear pattern whereas in the thalamus, pulvinar, precentral cortex, and precuneus, it follows a quadratic or exponential pattern. Age-related changes of iron content are different in the pulvinar and the rest of the thalamus as well as in internal and external globus pallidus. In the cortex, areas involved in motor and cognitive functions and visual processing show the highest iron increase with aging. We suggest that the departure from normal patterns of regional brain iron trajectories during aging may be helpful in the detection of subtle neurodegenerative and neuroinflammatory processes.
- Publikační typ
- časopisecké články MeSH
This study was conducted to determine the incidence of grey-white matter abnormalities (GWMAs) on magnetic resonance images (MRIs) in patients with hippocampal sclerosis (HS), to assess the inter-observer reliability of this finding, and to establish a possible relationship between GWMA and histopathological findings in the anterior part of the temporal lobe, as well as its other relation to clinical variables. We established a group of 55 patients with histologically proven HS. Three observers independently reviewed the MRIs to assess whether GWMA was present. Substantial independent inter-observer agreement was reached for 44 of the 55 patients (80%) (Fleiss' kappa 0.732; p<0.0001). GWMAs were present in 38% of patients (HS+GWMA). Focal cortical dysplasia (FCD) of type IIIa (ILAE classification) was present in 31% of patients. FCD type IIIa was present in 52.4% with HS+GWMA, and in 17.6% without GWMA (HS-GWMA) (p=0.007). We did not find any statistically significant differences in the postoperative outcomes between HS+GWMA and HS-GWMA. We did not find any statistically significant differences in the presence or absence of GWMA and FCD of the temporal pole in relation to the onset of epilepsy, the duration of epilepsy, or the presence of potential epileptogenic insults. GWMA in the anterior part of temporal lobe in patients with HS is a reliable assessment sign for observers who are experienced in evaluating the MRIs of epilepsy patients. The presence of GWMA is significantly associated with the presence of FCD type IIIa in these patients. The presence or absence of GWMA and FCD type IIIa does not influence the postoperative outcome of HS patients.
- MeSH
- anatomická značka patologie MeSH
- dítě MeSH
- dospělí MeSH
- epilepsie temporálního laloku patologie chirurgie MeSH
- hipokampus patologie MeSH
- laboratorní medicína metody normy statistika a číselné údaje MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody normy statistika a číselné údaje MeSH
- malformace mozkové kůry patologie chirurgie MeSH
- mladiství MeSH
- mladý dospělý MeSH
- odchylka pozorovatele MeSH
- retrospektivní studie MeSH
- skleróza patologie MeSH
- spánkový lalok patologie MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- validační studie MeSH
Meta-analyses, which present the best source of information on the effectiveness of interventions, are influenced by several biases. One category relates to the convenience of selective inclusion of those primary studies, which are more easily available than others. This availability bias includes bias from excluding the grey literature, bias from excluding non-English literature, and bias from excluding older studies. Existing studies are not conclusive about the impacts of this bias; in addition, none of them focus on road safety meta-analyses. To fill this gap, the present paper consisted of two studies: (1) exploring the presence of availability bias in road safety meta-analyses, and (2) demonstrating the impact of availability bias in several example meta-analyses. Based on an analysis of 80 existing meta-analyses, the first study concluded that compared to the medicine meta-analyses, the road safety meta-analyses use a longer time range, are more often restricted in terms of language, and less often involve the grey literature. The second study utilized selected unrestricted data samples to demonstrate the impact of availability bias in seven meta-analyses. The differences in intervention effectiveness in terms of crash frequency changes between unrestricted and restricted scenarios were identified. This shows that the search restrictions clearly lead to availability bias, which influences the differences in meta-analysis results.
The pharmaceutical production of recombinant proteins, such as monoclonal antibodies, is rather complex and requires proper development work. Accordingly, it is essential to develop appropriate scale-down models, which can mimic the corresponding production scale. In this work, we investigated the impact of the bioreactor scale on intracellular micro-heterogeneities of a CHO cell line producing monoclonal antibodies in fed-batch mode, using a 10 mL micro-bioreactor (ambr™) scale-down model and the corresponding 300 L pilot-scale bioreactor. For each scale, we measured the time evolution of the proteome, which enabled us to compare the impact of the bioreactor scale on the intracellular processes. Nearly absolute accordance between the scales was verified by data mining methods, such as hierarchical clustering and in-detail analysis on a single protein base. The time response of principal enzymes related to N-glycosylation was discussed, emphasizing major dissimilarities between the glycan fractions adorning the heavy chain and the corresponding protein abundance. The enzyme expression displayed mainly a constant profile, whereas the resulting glycan pattern changed over time. It is concluded that the enzymatic activity is influenced by the changing environmental conditions present in the fed-batch processes leading to the observed time-dependent variation.
- MeSH
- biologické modely * MeSH
- bioreaktory * MeSH
- CHO buňky MeSH
- Cricetulus MeSH
- glykosylace MeSH
- křečci praví MeSH
- monoklonální protilátky metabolismus MeSH
- proliferace buněk MeSH
- proteomika metody MeSH
- rekombinantní proteiny metabolismus MeSH
- shluková analýza MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p-FDR < 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.
- MeSH
- bílá hmota patologie diagnostické zobrazování MeSH
- deep learning MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční tomografie * metody MeSH
- mozeček * patologie diagnostické zobrazování MeSH
- posttraumatická stresová porucha * patologie patofyziologie diagnostické zobrazování MeSH
- šedá hmota patologie MeSH
- velikost orgánu MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
Among bird species, the most studied major histocompatibility complex (MHC) is the chicken MHC. Although the number of studies on MHC in free-ranging species is increasing, the knowledge on MHC variation in species closely related to chicken is required to understand the peculiarities of bird MHC evolution. Here we describe the variation of MHC class IIB (MHCIIB) exon 2 in a population of the Grey partridge (Perdix perdix), a species of high conservation concern throughout Europe and an emerging galliform model in studies of sexual selection. We found 12 alleles in 108 individuals, but in comparison to other birds surprisingly many sites show signatures of historical positive selection. Individuals displayed between two to four alleles both on genomic and complementary DNA, suggesting the presence of two functional MHCIIB loci. Recombination and gene conversion appear to be involved in generating MHCIIB diversity in the Grey partridge; two recombination breakpoints and several gene conversion events were detected. In phylogenetic analysis of galliform MHCIIB, the Grey partridge alleles do not cluster together, but are scattered through the tree instead. Thus, our results indicate that the Grey partridge MHCIIB is comparable to most other galliforms in terms of copy number and population polymorphism.
- MeSH
- alely MeSH
- druhová specificita MeSH
- exony genetika MeSH
- fylogeneze MeSH
- Galliformes genetika MeSH
- genová konverze * MeSH
- MHC antigeny II. třídy chemie genetika MeSH
- molekulární sekvence - údaje MeSH
- polymorfismus genetický * MeSH
- pravděpodobnostní funkce MeSH
- regulace genové exprese MeSH
- rekombinace genetická genetika MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sekvenční seřazení MeSH
- selekce (genetika) * MeSH
- substituce aminokyselin genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Effects of gender on grey matter (GM) volume differences in subcortical structures of the human brain have consistently been reported. Recent research evidence suggests that both gender and brain size influences volume distribution in subcortical areas independently. The goal of this study was to determine the effects of the interplay between brain size, gender and age contributing to volume differences of subcortical GM in the human brain. High-resolution T1-weighted images were acquired from 53 healthy males and 50 age-matched healthy females. Total GM volume was determined using voxel-based morphometry. We used model-based subcortical segmentation analysis to measure the volume of subcortical nuclei. Main effects of gender, brain volume and aging on subcortical structures were examined using multivariate analysis of variance. No significant difference was found in total brain volume between the two genders after correcting for total intracranial volume. Our analysis revealed significantly larger hippocampus volume for females. Additionally, GM volumes of the caudate nucleus, putamen and thalamus displayed a significant age-related decrease in males as compared to females. In contrast to this only the thalamic volume loss proved significant for females. Strikingly, GM volume decreases faster in males than in females emphasizing the interplay between aging and gender on subcortical structures. These findings might have important implications for the interpretation of the effects of unalterable factors (i.e. gender and age) in cross-sectional structural MRI studies. Furthermore, the volume distribution and changes of subcortical structures have been consistently related to several neuropsychiatric disorders (e.g. Parkinson's disease, attention deficit hyperactivity disorder, etc.). Understanding these changes might yield further insight in the course and prognosis of these disorders.
- MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mozek diagnostické zobrazování fyziologie MeSH
- multivariační analýza MeSH
- počítačové zpracování obrazu MeSH
- pohlavní dimorfismus * MeSH
- rozpoznávání automatizované MeSH
- šedá hmota diagnostické zobrazování fyziologie MeSH
- stárnutí patologie fyziologie MeSH
- velikost orgánu MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- MeSH
- bisfosfonáty terapeutické užití MeSH
- financování organizované MeSH
- fraktury kostí farmakoterapie prevence a kontrola MeSH
- imidazoly terapeutické užití MeSH
- inhibitory kostní resorpce terapeutické užití MeSH
- kyselina etidronová analogy a deriváty terapeutické užití MeSH
- lidé MeSH
- ligand RANK terapeutické užití MeSH
- metaanalýza jako téma MeSH
- monoklonální protilátky terapeutické užití MeSH
- organokovové sloučeniny terapeutické užití MeSH
- osteoporóza farmakoterapie mortalita MeSH
- randomizované kontrolované studie jako téma MeSH
- thiofeny terapeutické užití MeSH
- věkové faktory MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- komentáře MeSH
- souhrny MeSH
Age-related sarcopenia, resulting from a gradual loss in skeletal muscle mass and strength, is pivotal to the increased prevalence of functional limitation among the older adult community. The purpose of this meta-analysis of individual patient data is to investigate the difference in health-related quality of life between sarcopenic individuals and those without the condition using the Sarcopenia Quality of Life (SarQoL) questionnaire. A protocol was published on PROSPERO. Multiple databases and the grey literature were searched until March 2023 for studies reporting quality of life assessed with the SarQoL for patients with and without sarcopenia. Two researchers conducted the systematic review independently. A two-stage meta-analysis was performed. First, crude (mean difference) and adjusted (beta coefficient) effect sizes were calculated within each database; then, a random effect meta-analysis was applied to pool them. Heterogeneity was measured using the Q-test and I2 value. Subgroup analyses were performed to investigate the source of potential heterogeneity. The strength of evidence of this association was assessed using GRADE. From the 413 studies identified, 32 were eventually included, of which 10 were unpublished data studies. Sarcopenic participants displayed significantly reduced health-related quality of life compared with non-sarcopenic individuals (mean difference = -12.32; 95 % CI = [-15.27; -9.37]). The model revealed significant heterogeneity. Subgroup analyses revealed a substantial impact of regions, clinical settings, and diagnostic criteria on the difference in health-related quality of life between sarcopenic and non-sarcopenic individuals. The level of evidence was moderate. This meta-analysis of individual patient data suggested that sarcopenia is associated with lower health-related quality of life measured with SarQoL.
- MeSH
- kvalita života MeSH
- lidé MeSH
- prevalence MeSH
- průzkumy a dotazníky MeSH
- sarkopenie * epidemiologie MeSH
- senioři MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- přehledy MeSH
Déjà vu (DV) is an eerie phenomenon experienced frequently as an aura of temporal lobe epilepsy, but also reported commonly by healthy individuals. The former pathological manifestation appears to result from aberrant neural activity among brain structures within the medial temporal lobes. Recent studies also implicate medial temporal brain structures in the non-pathological experience of DV, but as one element of a diffuse neuroanatomical correlate; it remains to be seen if neural activity among the medial temporal lobes also underlies this benign manifestation. The present study set out to investigate this. Due to its unpredictable and infrequent occurrence, however, non-pathological DV does not lend itself easily to functional neuroimaging. Instead, we draw on research showing that brain structure covaries among regions that interact frequently as nodes of functional networks. Specifically, we assessed whether grey-matter covariance among structures implicated in non-pathological DV differs according to the frequency with which the phenomenon is experienced. This revealed two diverging patterns of structural covariation: Among the first, comprised primarily of medial temporal structures and the caudate, grey-matter volume becomes more positively correlated with higher frequency of DV experience. The second pattern encompasses medial and lateral temporal structures, among which greater DV frequency is associated with more negatively correlated grey matter. Using a meta-analytic method of co-activation mapping, we demonstrate a higher probability of functional interactions among brain structures constituting the former pattern, particularly during memory-related processes. Our findings suggest that altered neural signalling within memory-related medial temporal brain structures underlies both pathological and non-pathological DV.
- MeSH
- databáze jako téma MeSH
- déja vu * MeSH
- dospělí MeSH
- epilepsie temporálního laloku diagnostické zobrazování patofyziologie psychologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- mapování mozku metody MeSH
- metaanalýza jako téma MeSH
- metoda nejmenších čtverců MeSH
- mladý dospělý MeSH
- nervové dráhy diagnostické zobrazování fyziologie patofyziologie MeSH
- nucleus caudatus diagnostické zobrazování fyziologie patofyziologie MeSH
- šedá hmota diagnostické zobrazování fyziologie patofyziologie MeSH
- spánkový lalok diagnostické zobrazování fyziologie patofyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
