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Neurons in the CNS lose regenerative potential with maturity, leading to minimal corticospinal tract (CST) axon regrowth after spinal cord injury (SCI). In young rodents, knockdown of PTEN, which antagonizes PI3K signaling by hydrolyzing PIP3, promotes axon regeneration following SCI. However, this effect diminishes in adults, potentially due to lower PI3K activation leading to reduced PIP3. This study explores whether increased PIP3 generation can promote long-distance regeneration in adults. We used a hyperactive PI3K, PI3Kδ (PIK3CD), to boost PIP3 levels in mature cortical neurons and assessed CST regeneration after SCI. Adult rats received AAV1-PIK3CD and AAV1-eGFP, or AAV1-eGFP alone, in the sensorimotor cortex concurrent with a C4 dorsal SCI. Transduced neurons showed increased pS6 levels, indicating elevated PI3K/Akt/mTOR signaling. CST regeneration, confirmed with retrograde tracing, was evaluated up to 16 weeks post injury. At 12 weeks, ∼100 axons were present at lesion sites, doubling to 200 by 16 weeks, with regeneration indices of 0.1 and 0.2, respectively. Behavioral tests showed significant improvements in paw reaching, grip strength, and ladder-rung walking in PIK3CD-treated rats, corroborated by electrophysiological recordings of cord dorsum potentials and distal flexor muscle electromyography. Thus, PI3Kδ upregulation in adult cortical neurons enhances axonal regeneration and functional recovery post SCI.
- MeSH
- axony metabolismus fyziologie MeSH
- Dependovirus genetika MeSH
- fosfatidylinositol-3-kinasy třídy I metabolismus genetika MeSH
- fosfatidylinositol-3-kinasy metabolismus MeSH
- genetické vektory genetika MeSH
- krysa rodu rattus MeSH
- modely nemocí na zvířatech MeSH
- neurony metabolismus MeSH
- obnova funkce MeSH
- poranění míchy * metabolismus terapie genetika MeSH
- pyramidové dráhy * metabolismus MeSH
- regenerace nervu * MeSH
- signální transdukce MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Electrospinning is a widely employed manufacturing platform for tissue engineering applications because it produces structures that closely mimic the extracellular matrix. Herein, we demonstrate the potential of poly(vinyl alcohol) (PVA) electrospun nanofibers as scaffolds for tissue engineering. Nanofibers were created by needleless direct current electrospinning from PVA with two different degrees of hydrolysis (DH), namely 98% and 99% and subsequently heat treated at 180 °C for up to 16 h to render them insoluble in aqueous environments without the use of toxic cross-linking agents. Despite the small differences in the PVA chemical structure, the changes in the material properties were substantial. The higher degree of hydrolysis resulted in non-woven supports with thinner fibres (285 ± 81 nm c.f. 399 ± 153 nm) that were mechanically stronger by 62% (±11%) and almost twice as more crystalline than those from 98% hydrolysed PVA. Although prolonged heat treatment (16 h) did not influence fibre morphology, it reduced the crystallinity and tensile strength for both sets of materials. All samples demonstrated a lack or very low degree of haemolysis (<5%), and there were no notable changes in their anticoagulant activity (≤3%). Thrombus formation, on the other hand, increased by 82% (±18%) for the 98% hydrolysed samples and by 71% (±10%) for the 99% hydrolysed samples, with heat treatment up to 16 h, as a direct consequence of the preservation of the fibrous morphology. 3T3 mouse fibroblasts showed the best proliferation on scaffolds that were thermally stabilised for 4 and 8 h. Overall these scaffolds show potential as 'greener' alternatives to other electrospun tissue engineering materials, especially in cases where they may be used as delivery vectors for heat tolerant additives.
- Publikační typ
- časopisecké články MeSH
Verifying the speaker of a speech fragment can be crucial in attributing a crime to a suspect. The question can be addressed given disputed and reference speech material, adopting the recommended and scientifically accepted likelihood ratio framework for reporting evidential strength in court. In forensic practice, usually, auditory and acoustic analyses are performed to carry out such a verification task considering a diversity of features, such as language competence, pronunciation, or other linguistic features. Automated speaker comparison systems can also be used alongside those manual analyses. State-of-the-art automatic speaker comparison systems are based on deep neural networks that take acoustic features as input. Additional information, though, may be obtained from linguistic analysis. In this paper, we aim to answer if, when and how modern acoustic-based systems can be complemented by an authorship technique based on frequent words, within the likelihood ratio framework. We consider three different approaches to derive a combined likelihood ratio: using a support vector machine algorithm, fitting bivariate normal distributions, and passing the score of the acoustic system as additional input to the frequent-word analysis. We apply our method to the forensically relevant dataset FRIDA and the FISHER corpus, and we explore under which conditions fusion is valuable. We evaluate our results in terms of log likelihood ratio cost (Cllr) and equal error rate (EER). We show that fusion can be beneficial, especially in the case of intercepted phone calls with noise in the background.
- MeSH
- akustika řeči MeSH
- algoritmy MeSH
- lidé MeSH
- lingvistika MeSH
- pravděpodobnostní funkce MeSH
- řeč MeSH
- soudní vědy * metody MeSH
- support vector machine MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Recombinant adeno-associated viral vectors (AAVs) are an effective system for gene transfer. AAV serotype 2 (AAV2) is commonly used to deliver transgenes to retinal ganglion cells (RGCs) via intravitreal injection. The AAV serotype however is not the only factor contributing to the effectiveness of gene therapies. Promoters influence the strength and cell-selectivity of transgene expression. This study compares five promoters designed to maximise AAV2 cargo space for gene delivery: chicken β-actin (CBA), cytomegalovirus (CMV), short CMV early enhancer/chicken β-actin/short β-globulin intron (sCAG), mouse phosphoglycerate kinase (PGK), and human synapsin (SYN). The promoters driving enhanced green fluorescent protein (eGFP) were examined in adult C57BL/6J mice eyes and tissues of the visual system. eGFP expression was strongest in the retina, optic nerves and brain when driven by the sCAG and SYN promoters. CBA, CMV, and PGK had moderate expression by comparison. The SYN promoter had almost exclusive transgene expression in RGCs. The PGK promoter had predominant expression in both RGCs and AII amacrine cells. The ubiquitous CBA, CMV, and sCAG promoters expressed eGFP in a variety of cell types across multiple retinal layers including Müller glia and astrocytes. We also found that these promoters could transduce human retina ex vivo, although expression was predominantly in glial cells due to low RGC viability. Taken together, this promoter comparison study contributes to optimising AAV-mediated transduction in the retina, and could be valuable for research in ocular disorders, particularly those with large or complex genetic cargos.
- MeSH
- aktiny genetika metabolismus MeSH
- cytomegalovirové infekce * genetika metabolismus MeSH
- Dependovirus genetika metabolismus MeSH
- genetické vektory genetika MeSH
- lidé MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- Parvovirinae * genetika MeSH
- retinální gangliové buňky metabolismus MeSH
- transdukce genetická MeSH
- transgeny MeSH
- zelené fluorescenční proteiny genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Observational studies made it possible to assess the impact of risk factors on the long-term effectiveness of mRNA and adenoviral vector (AdV) vaccines against COVID-19. METHODS: A computerized literature search was undertaken using the MEDLINE, EMBASE, and MedRxiv databases to identify eligible studies, with no language restrictions, published up to 28 February 2022. Eligible were observational studies assessing vaccine effectiveness (VE) by disease severity with reference groups of unvaccinated participants or participants immunized with one, two, or three vaccine doses. Our study was carried out in compliance with the PRISMA and MOOSE guidelines. The risk of study bias was identified using the Newcastle-Ottawa Quality Assessment Scale. The GRADE guidelines were applied to assess the strength of evidence for the primary outcome. The synthesis was conducted using a meta-analysis and meta-regression. RESULTS: Out of a total of 14,155 publications, 290 studies were included. Early VE of full vaccination against COVID-19 of any symptomatology and severity decreased from 96% (95% CI, 95-96%) for mRNA and from 86% (95% CI, 83-89%) for AdV vaccines to 67% for both vaccine types in the last 2 months of 2021. A similar 1-year decline from 98 to 86% was found for severe COVID-19 after full immunization with mRNA, but not with AdV vaccines providing persistent 82-87% effectiveness. Variant-reduced VE was only associated with Omicron regardless of disease severity, vaccine type, or vaccination completeness. The level of protection was reduced in participants aged >65 years, with a comorbidity or those in long-term care or residential homes independently of the number of doses received. The booster effect of the third mRNA dose was unclear because incompletely restored effectiveness, regardless of disease severity, declined within a short-term interval of 4 months. CONCLUSIONS: Full vaccination provided an early high, yet waning level of protection against COVID-19 of any severity with a strong impact on the high-risk population. Moreover, the potential risk of new antigenically distinct variants should not be underestimated, and any future immunization strategy should include variant-updated vaccines.
Random Forest is an ensemble of decision trees based on the bagging and random subspace concepts. As suggested by Breiman, the strength of unstable learners and the diversity among them are the ensemble models' core strength. In this paper, we propose two approaches known as oblique and rotation double random forests. In the first approach, we propose rotation based double random forest. In rotation based double random forests, transformation or rotation of the feature space is generated at each node. At each node different random feature subspace is chosen for evaluation, hence the transformation at each node is different. Different transformations result in better diversity among the base learners and hence, better generalization performance. With the double random forest as base learner, the data at each node is transformed via two different transformations namely, principal component analysis and linear discriminant analysis. In the second approach, we propose oblique double random forest. Decision trees in random forest and double random forest are univariate, and this results in the generation of axis parallel split which fails to capture the geometric structure of the data. Also, the standard random forest may not grow sufficiently large decision trees resulting in suboptimal performance. To capture the geometric properties and to grow the decision trees of sufficient depth, we propose oblique double random forest. The oblique double random forest models are multivariate decision trees. At each non-leaf node, multisurface proximal support vector machine generates the optimal plane for better generalization performance. Also, different regularization techniques (Tikhonov regularization, axis-parallel split regularization, Null space regularization) are employed for tackling the small sample size problems in the decision trees of oblique double random forest. The proposed ensembles of decision trees produce trees with bigger size compared to the standard ensembles of decision trees as bagging is used at each non-leaf node which results in improved performance. The evaluation of the baseline models and the proposed oblique and rotation double random forest models is performed on benchmark 121 UCI datasets and real-world fisheries datasets. Both statistical analysis and the experimental results demonstrate the efficacy of the proposed oblique and rotation double random forest models compared to the baseline models on the benchmark datasets.
- MeSH
- algoritmy * MeSH
- analýza hlavních komponent MeSH
- rotace MeSH
- support vector machine * MeSH
- Publikační typ
- časopisecké články MeSH
Age-related hearing loss is manifested primarily by a decreased sensitivity to faint sounds, that is, by elevation of the hearing thresholds. Nevertheless, aging also affects the ability of the auditory system to process temporal parameters of the sound stimulus. To explore the precision and reliability of auditory temporal processing during aging, responses to several types of sound stimuli were recorded from neurons of the auditory cortex (AC) of young and aged anaesthetized Fischer 344 rats. In response to broad-band noise bursts, the aged rats exhibited larger response magnitudes, a higher proportion of monotonic units, and also a larger variability of response magnitudes, suggesting a lower stability of the rate code. Of primary interest were the responses to temporally structured stimuli (amplitude-modulated (AM) noise, frequency-modulated (FM) tones, and click trains) recorded separately in the right and left AC. Significant differences of temporal processing were already found between the neuronal responses in the left and right AC in the young animals: for the click trains, the left hemisphere exhibited a greater responsiveness to higher repetition rates, lower vector strength values, and a lower similarity of responses. The two hemispheres were also affected differently by aging. In the right hemisphere, neurons in the aged animals displayed worse synchronization with the AM noise and clicks, but better synchronization with the FM tone. In the left hemisphere, neuronal synchronization with the stimulus modulation improved at a higher age for all three stimuli. The results show that the ability of the aging auditory system to process temporal parameters of the stimulus strongly depends on the stimulus type and on laterality. Furthermore, the commonly reported age-related decline in the temporal processing ability cannot be regarded as general as, at least at the neuronal level in the AC, objective measures of the temporal representation often exhibit age-related improvement instead of deterioration.
While brain imaging tools like functional magnetic resonance imaging (fMRI) afford measurements of whole-brain activity, it remains unclear how best to interpret patterns found amid the data's apparent self-organization. To clarify how patterns of brain activity support brain function, one might identify metric spaces that optimally distinguish brain states across experimentally defined conditions. Therefore, the present study considers the relative capacities of several metric spaces to disambiguate experimentally defined brain states. One fundamental metric space interprets fMRI data topographically, that is, as the vector of amplitudes of a multivariate signal, changing with time. Another perspective compares the brain's functional connectivity, that is, the similarity matrix computed between signals from different brain regions. More recently, metric spaces that consider the data's topology have become available. Such methods treat data as a sample drawn from an abstract geometric object. To recover the structure of that object, topological data analysis detects features that are invariant under continuous deformations (such as coordinate rotation and nodal misalignment). Moreover, the methods explicitly consider features that persist across multiple geometric scales. While, certainly, there are strengths and weaknesses of each brain dynamics metric space, wefind that those that track topological features optimally distinguish experimentally defined brain states.
- Publikační typ
- časopisecké články MeSH
Léčba spinální svalové atrofie (SMA) s vazbou na 5q chromozom v posledních letech zažívá převratné změny. Dříve kauzálně neléčitelné onemocnění je od roku 2016 (v EU od roku 2017) nově léčitelné, aktuálně jsou již registrované 3 kauzální léky. Dva léky nusinesren (Spinraza) a risdiplam (Evrysdi) zvyšují tvorbu chybějícího SMN proteinu modulací transkripce RNA genu SMN2. Tyto léky proto musí být podávány opakovaně, celoživotně. Třetí lék, onasemnogene abeparvovec (Zolgensma) nahrazuje chybějící gen SMN1 genem syntetickým, který je do těla pacienta přenesen virovým vektorem. Jedná se o první systémovou genovou léčbu v medicíně vůbec, jako virový vektor je použit AAV9. Prozatím je u tohoto léku pouze jedno podání, aktuálně máme dostupná data o minimálně 4,5letém efektu léčby. Prvním kauzálním lékem byl lék nusinersen. Jeho výhodou je dlouhodobá, dnes již 10letá zkušenost, a velký počet odléčených pacientů, již 10 000 pacientů. Jelikož lék nepřechází hematoencefalickou barieru je podáván v pravidelných intervalech intratekálně. Nusinersen má v ČR úhradu pro všechny typy i věkové skupiny pacientů se SMA. Nově, v srpnu 2020, byl v USA regsitrovaný lék risdiplam, který má výhodu perorálního podání. Jeho nevýhodou je však krátká klinická zkušenost, a omezená dostupnost v ČR. Jelikož prozatím není registrován v EU, předpokládaná doba registrace je jaro 2020, je v ČR dostupný pouze formou specifického léčebného programu pro pacienty SMA typu 1 a 2. Třetím kauzálním lékem, a druhým lékem registrovaným v EU, je lék onasemngen abeparvovek. Tato léčba je však díky cestě podání vhodná pouze pro část dětské populace se SMA, indikační kriteria léčby se v jednotlivých zemích mírně liší, v ČR je léčba prozatím dostupná pro pacienty se SMA do 2+ let (den před 3. narozeninami) a do váhy 13,5 kg. Kromě již registrovaných léků probíhají četné klinické studie experimentální léčby modifikující důsledky nemoci – neuroprotektivní léky a léky podporující vitalitu svalů. Dostupnost kauzální léčby však neznamená, že jsme dnes schopni symptomatické pacienty vyléčit. Léčba prozatím mírně zlepšuje motorické dovednosti pacientů a zejména stabilizuje stav, významně zabraňuje progresi nemoci. Z tohoto důvodu je stále zásadní léčba symptomatická, která je multioborová a měla by proto být poskytována v Neuromuskulárních centrech.
The therapy of spinal muscular atrophy (SMA) with a link to 5q chromosome is nowadays a very hot area. A previously casually not treatable disease, it has been in the US since 2016, and in Europe since 2017. It is newly treatable, and nowadays there are three causal drugs. Two of them, nusinersen (Spinraza) and risdiplam (Ervysdi) increase the synthesis of the SMN protein by modulation of the RNA transcription of the SMN2 gene. These drugs have to be taken regularly, and are lifelong. The third drug, onasemnogene abeparvovec (Zolgensma) is able to substitute the missing SMN1 gene by a syntetic SMN1 gene delivered by viral vector AAV9. It is the first systemic gene therapy in medicine. Until now, this drug was taken only once. There are 4.5 years of data proving its sustaining effect. The first causal therapy was the drug Nusinersen. It has the huge advantage of 10 years’ experience with a high number of treated patients, more than 10,000. This drug does not go through the cerebro-spinal barrier, due to it having to be applied intrathecaly. Nusinersen is in CZ reimbursed for all types and ages of SMA patients. Recently, in August 2020, the drug risdiplam was registered in the US. Its advantage is per oral application; its disadvantage is the short experiences and limited acces in CZ. Risdiplam is not yet registered in the EU, due to this it is available only through the early access program for SMA patients type 1 and 2. The third causal therapy, and second registered drug in the EU, is onasemnogene abeparvovec. Due to the systemic delivery this therapy is limited only for children before the age of 3 years and weighing less than 13.5 kg. Besides, the already registered therapies there are many clinical trials with experimental drugs ongoing – many neuroprotective drugs and muscle strength-enhancing compounds. The actual therapy cannot help with all the symptoms of the disease, it can only mildly improve the motor function and primarily slow down the progression. Due to this, there is still a need for multidisciplinary symptomatic care that should be provided in Neuromuscular Centres.
- Klíčová slova
- modulace RNA, léčba symptomatická, nervosvalová centra,
- MeSH
- genetická terapie metody MeSH
- lidé MeSH
- spinální svalová atrofie * genetika terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
... Interactions • Receptor-Ligand Binding Occurs via Multiple Noncovalent Bonds • How Do We Describe the Strength ... ... Questions 634 -- Chapter 17: Infectious Diseases and Vaccines 637 -- The Importance of Barriers and Vectors ...
Eight edition různé stránkování : barevné ilustrace ; 28 cm
