microstructure analysis
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Patofyzioiogickým podkladem narkolepsie-kataplexie je ztráta hypokretinových neuronů posterolaterálního hypotalamu. Předpokládaným projevem tohoto deficitu je změna mikrostruktury a autonomních funkcí ve spánku u těchto pacientů. Cílem studie bylo hodnocení mikrostruktury NREM (non-rapid eye movement) spánku metodou sledování cyklických alternujících vzorců (CAP) a změny variability srdeční frekvence (HRV). Do studie bylo zahrnuto 15 pacientů s narkolepsiíkataplexií (průměrný věk 35 8,5 věkové rozmezí 22-44 let) a 15 zdravých kontrol (31 ± 11,4; 19-48 let). Obě skupiny podstoupily 2 následná polysomnografická vyšetření, pro analýzu CAP a HRV byla zpracována data ze 2. noci. Prokázali jsme signifikantní snížení CAP, provázené sníŽením LF a zvýšením HF složky při redukci poměru LF/HF v průběhu NREM spánku. Výsledky vyjadřují poruchu kolísání prahu probuzení u narkolepsie-kataplexie, která je provázena redukcí tonu sympatiku během NREM spánku. Domníváme se, narkolepsie nevzniká pouze v důsledku poruchy regulace REM spánku, nýbrž že je současně vlivem deficientní hypokretinové modulace alt porušena i regulace NREM spánku.
The present study was aimed at analysing the non-rapid eye movement (NREM) sleep microstructure by the cyclic alternating pattern (CAP) and at assessing the heart rate variability (HRV) changes in patiens with narcolepsy, hypothesizing a correlation of an abnormal sleep microstructure and abnormal autonomic response with a selective loss of hypocretin-containing neurons in narcolepsy. Fifteen patients with narcolepsy-cataplexy (mean age 35±8.5; age range 22-44), and 15 age and sex matched controls (mean age 31±11.4; age range 19-48) were included in the study. All subjects underwent polysomnography recordings for two consecutive nights in a standard laboratory setting. The sleep scoring was focused on the CAP and HRV analysis. A significant decrease in CAP rate as well as significant reduction of the LF spectral band and the LF/HF ratio, and the elevation of the HF spectral component during NREM 4 stage were revealed in narcoleptics compared to controls. Our results suggest that physiological fluctuation of arousal during sleep described as CAP is impaired in narcolepsy and accompained by reduced sympathetic tone during SWS. We have hypothesized that the whole sleep regulation process is altered in narcolepsy and not only REM sleep mechanisms.
- MeSH
- elektroencefalografie metody využití MeSH
- finanční podpora výzkumu jako téma MeSH
- interpretace statistických dat MeSH
- lidé MeSH
- narkolepsie diagnóza etiologie MeSH
- neuropeptidy nedostatek MeSH
- poruchy spánku a bdění diagnóza etiologie patofyziologie MeSH
- spánek REM fyziologie MeSH
- srdeční frekvence fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
An increase in procollagen type I amino-terminal propeptide (PINP) early after teriparatide initiation was shown to correlate with increased lumbar spine areal BMD and is a good predictor of the anabolic response to teriparatide. Few data exist correlating PINP and bone microstructure, and no data exist in patients on teriparatide following prior potent antiresorptive treatment. This exploratory analysis aimed to investigate the effects of teriparatide on cancellous bone microstructure and correlations of bone markers with microstructure in alendronate-pretreated patients. This was a post hoc analysis of changes in bone markers and three-dimensional indices of bone microstructure in paired iliac crest biopsies from a prospective teriparatide treatment study in postmenopausal women with osteoporosis who were either treatment-naïve (TN, n=16) or alendronate-pretreated (ALN, n=29) at teriparatide initiation. Teriparatide (20μg/day) was given for 24months; biopsies were taken at baseline and endpoint, and serum concentrations of PINP and type 1 collagen cross-linked C-telopeptide (βCTX) were measured at intervals up to 24months. In the TN and ALN groups, respectively, mean (SD) increases in three-dimensional bone volume/tissue volume were 105 (356)% (P=0.039) and 55 (139)% (P<0.005) and trabecular thickness 30.4 (30)% (P<0.001) and 30.8 (53)% (P<0.001). No significant changes were observed in trabecular number or separation. In the ALN patients, 3-month change of neither PINP nor βCTX correlated with indices of cancellous bone microstructure. However, 12-month changes in biochemical bone markers correlated significantly with improvements in bone volume/tissue volume, r=0.502 (P<0.01) and r=0.378 (P<0.05), trabecular number, r=0.559 (P<0.01) and r=0.515 (P<0.01), and reduction of trabecular separation, r=-0.432 (P<0.05) and r=-0.530 (P<0.01), for PINP and βCTX, respectively. We conclude that cancellous bone microstructure improved with teriparatide therapy irrespective of prior antiresorptive use.
- MeSH
- alendronát terapeutické užití MeSH
- inhibitory kostní resorpce terapeutické užití MeSH
- kolagen typu I krev MeSH
- kostní denzita účinky léků MeSH
- lidé středního věku MeSH
- lidé MeSH
- peptidové fragmenty krev MeSH
- peptidy krev MeSH
- postmenopauzální osteoporóza farmakoterapie MeSH
- prokolagen krev MeSH
- remodelace kosti účinky léků MeSH
- senioři MeSH
- teriparatid terapeutické užití MeSH
- trabekulární kostní tkáň účinky léků MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- klinické zkoušky MeSH
- multicentrická studie MeSH
- práce podpořená grantem MeSH
One of the most widely investigated functions of the brain is vision. Whereas special attention is often paid to motion detection and its modulation by attention, comparatively still little is known about the structural background of this function. We therefore, examined the white matter microstructural background of coherent motion detection. A random-dot kinematogram paradigm was used to measure the sensitivity of healthy individuals׳ to movement coherence. The potential correlation was investigated between the motion detection threshold and the white matter microstructure as measured by high angular resolution diffusion MRI. The Track Based Spatial Statistics method was used to address this correlation and probabilistic tractography to reveal the connection between identified regions. A significant positive correlation was found between the behavioural data and the local fractional anisotropy in the posterior part of the right superior frontal gyrus, the right juxta-cortical superior parietal lobule, the left parietal white matter, the left superior temporal gyrus and the left optic radiation. Probabilistic tractography identified pathways that are highly similar to the segregated attention networks, which have a crucial role in the paradigm. This study draws attention to the structural determinant of a behavioural function.
- MeSH
- anizotropie MeSH
- bílá hmota anatomie a histologie fyziologie MeSH
- diferenční práh fyziologie MeSH
- difuzní magnetická rezonance MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mozek anatomie a histologie fyziologie MeSH
- nervové dráhy anatomie a histologie fyziologie MeSH
- psychofyzika MeSH
- světelná stimulace MeSH
- teorie detekce signálu fyziologie MeSH
- vnímání pohybu fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The high rate of occurrence of sleep disturbances in children with attention-deficit/hyperactivity disorder (ADHD) prompted the idea that structural and neurotransmitter changes might give rise to specific sleep pattern abnormalities. The aim of this study was to evaluate the microstructure of sleep in children with ADHD who had no polysomnographically diagnosed sleep disorder, had never been treated for ADHD, and were free from any psychiatric comorbidity. Participants were 14 patients with ADHD (12 boys and 2 girls aged 7-12 years, mean age 9.6±1.6). ADHD was diagnosed according to DSM-IV criteria (Diagnostic and statistical manual of mental disorders). Psychiatric comorbidities were ruled out by detailed psychiatric examination. The patients underwent two consecutive overnight video-polysomnographic (PSG) recordings, with the sleep microstructure (cyclic alternating pattern – CAP) scoring during the second night. The data were compared with age- and sex-matched controls. Sleep microstructure analysis using CAP revealed no significant differences between the ADHD group and the controls in any of the parameters under study. In conclusions, no ADHD-specific alterations were found in the sleep microstructure.
- MeSH
- dítě MeSH
- hyperkinetická porucha komplikace patofyziologie psychologie MeSH
- lidé MeSH
- polysomnografie MeSH
- poruchy spánku a bdění komplikace patofyziologie MeSH
- studie případů a kontrol MeSH
- stupeň závažnosti nemoci MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
- MeSH
- aneuploidie MeSH
- cytogenetické vyšetření metody statistika a číselné údaje MeSH
- exprese genu MeSH
- faktor VIII genetika MeSH
- femur anatomie a histologie MeSH
- finanční podpora výzkumu jako téma MeSH
- geneticky modifikovaná zvířata anatomie a histologie genetika MeSH
- Haversův systém anatomie a histologie MeSH
- králíci MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
BACKGROUND: Histological evidence suggests that pathology in Parkinson's disease (PD) goes beyond nigrostriatal degeneration and also affects the cerebral cortex. Quantitative MRI (qMRI) techniques allow the assessment of changes in brain tissue composition. However, the development and pattern of disease-related cortical changes have not yet been demonstrated in PD with qMRI methods. The aim of this study was to investigate longitudinal cortical microstructural changes in PD with quantitative T1 relaxometry. METHODS: 13 patients with mild to moderate PD and 20 matched healthy subjects underwent high resolution T1 mapping at two time points with an interval of 6.4 years (healthy subjects: 6.5 years). Data from two healthy subjects had to be excluded due to MRI artifacts. Surface-based analysis of cortical T1 values was performed with the FreeSurfer toolbox. RESULTS: In PD patients, a widespread decrease of cortical T1 was detected during follow-up which affected large parts of the temporo-parietal and occipital cortices and also frontal areas. In contrast, age-related T1 decrease in the healthy control group was much less pronounced and only found in lateral frontal, parietal and temporal areas. Average cortical T1 values did not differ between the groups at baseline (p = 0.17), but were reduced in patients at follow-up (p = 0.0004). Annualized relative changes of cortical T1 were higher in patients vs. healthy subjects (patients: - 0.72 ± 0.64%/year; healthy subjects: - 0.17 ± 0.41%/year, p = 0.007). CONCLUSIONS: In patients with PD, the development of widespread changes in cortical microstructure was observed as reflected by a reduction of cortical T1. The pattern of T1 decrease in PD patients exceeded the normal T1 decrease as found in physiological aging and showed considerable overlap with the pattern of cortical thinning demonstrated in previous PD studies. Therefore, cortical T1 might be a promising additional imaging marker for future longitudinal PD studies. The biological mechanisms underlying cortical T1 reductions remain to be further elucidated.
- MeSH
- lidé středního věku MeSH
- lidé MeSH
- longitudinální studie MeSH
- magnetická rezonanční tomografie metody MeSH
- mozková kůra diagnostické zobrazování MeSH
- Parkinsonova nemoc diagnostické zobrazování MeSH
- senioři MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The outcomes from the feasibility study on utilization of synchrotron radiation X-ray microtomography (SR-μCT) to investigate the texture and the quantitative mineralogical composition of selected calcium oxalate-based urinary calculi fragments are presented. The comparison of the results obtained by SR-μCT analysis with those derived from current standard analytical approaches is provided. SR-μCT is proved as a potential effective technique for determination of texture, 3D microstructure, and composition of kidney stones.
- MeSH
- krystalizace MeSH
- lidé středního věku MeSH
- lidé MeSH
- močové kameny chemie MeSH
- rentgenová mikrotomografie MeSH
- studie proveditelnosti MeSH
- synchrotrony MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: Microstructural characterization of patients with multiple sclerosis (MS) has been shown to correlate better with disability compared to conventional radiological biomarkers. Quantitative MRI provides effective means to characterize microstructural brain tissue changes both in lesions and normal-appearing brain tissue. However, the impact of the location of microstructural alterations in terms of neuronal pathways has not been thoroughly explored so far. Here, we study the extent and the location of tissue changes probed using quantitative MRI along white matter (WM) tracts extracted from a connectivity atlas. METHODS: We quantified voxel-wise T1 tissue alterations compared to normative values in a cohort of 99 MS patients. For each WM tract, we extracted metrics reflecting tissue alterations both in lesions and normal-appearing WM and correlated these with cross-sectional disability and disability evolution after 2 years. RESULTS: In early MS patients, T1 alterations in normal-appearing WM correlated better with disability evolution compared to cross-sectional disability. Further, the presence of lesions in supratentorial tracts was more strongly associated with cross-sectional disability, while microstructural alterations in infratentorial pathways yielded higher correlations with disability evolution. In progressive patients, all major WM pathways contributed similarly to explaining disability, and correlations with disability evolution were generally poor. CONCLUSIONS: We showed that microstructural changes evaluated in specific WM pathways contribute to explaining future disability in early MS, hence highlighting the potential of tract-wise analyses in monitoring disease progression. Further, the proposed technique allows to estimate WM tract-specific microstructural characteristics in clinically compatible acquisition times, without the need for advanced diffusion imaging.
- MeSH
- bílá hmota * diagnostické zobrazování patologie MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody MeSH
- mozek diagnostické zobrazování patologie MeSH
- průřezové studie MeSH
- roztroušená skleróza * diagnostické zobrazování patologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
