483 research outputs found

    Učinak eksrakta kore brucijskog bora (Pinus brutia) na čiste i mješovite kulture buražnih bakterija i arheja te na fermentacijske značajke buraga in vitro

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    The aim of the study was to investigate the effects of Pinus brutia bark extract, which is rich in polyphenolic compounds of tannins, on both pure and mixed continuous cultures of rumen bacteria and archaea, as well as on rumen fermentation characteristics in vitro. Antimicrobial susceptibility assay with pure cultures was carried out in an anaerobic chamber. Pinus brutia bark extract exhibited a potential inhibitor activity (P<0.05) against pure cultures of Ruminococcus flavefaciens, Eubacterium ruminantium, and Methanobacterium formicicum while a growth stimulatory effect (P<0.05) was observed for Ruminoccocus albus, Butyrivibrio fibrisolvens, and Streptococcus bovis. Pinus brutia bark extract only had a potential inhibitor effect (P<0.05) on R. albus at the highest dose (1200 μg/mL). Pinus brutia bark extract also stimulated (P<0.05) the growth of pure cultures of Fibrobacter succinogenes, while it did not affect Megasphaera elsdenii, except at the highest dose. The effects of two doses (75 and 375 mg/L) of P. brutia bark extract on in vitro mixed cultures and rumen fermentation parameters were determined by the rumen simulation technique (Rusitec). Supplementation with P. brutia bark extract led to a quadratic decrease (P<0.05) in the cell numbers of R. flavefaciens. Production of total and individual short chain fatty acids (SCFA), acetate to propionate ratio (C2/C3), total protozoa, ruminal pH, and dry matter digestibility (DMD) did not change in the presence of P. brutia bark extract. Supplementation with both doses of P. brutia bark extract decreased (P<0.05) the ammonia-N concentrations. Ammonia-N concentration was lowest in the high-supplemented group (P<0.05). As a conclusion, inhibitory effects of P. brutia bark extract on some species in the pure cultures were in the same direction as with mixed ruminal cultures, while stimulatory effects disappeared. The lack of inhibitory effects on protozoa and on a large number of Gram-positive rumen bacteria in the mixed cultures suggests that its mechanism of action is not exactly similar to antibiotics. Although P. brutia bark extract did not alter ruminal SCFA, it could have potential to improve ruminal protein utilization without depressing rumen microbial fermentation.Cilj ovog rada bio je istražiti učinak ekstrakta kore brucijskog bora (Pinus brutia), koji je bogat polifenolnim sastojcima tanina, na čiste i mješovite kulture buražnih bakterija i arheja kao i na in vitro fermentacijske značajke buraga. Proveden je test antimikrobne osjetljivosti s čistim kulturama u anaerobnim uvjetima. Ekstrakt kore brucijskog bora pokazao je potencijalnu inhibitornu aktivnost (P < 0,05) protiv čistih kultura bakterija Ruminococcus flavefaciens, Eubacterium ruminantium i Methanobacterium formicicum, a stimulacijski učinak na rast (P < 0,05) opažen je za bakterije Ruminoccocus albus, Butyrivibrio fibrisolvens i Streptococcus bovis. Ekstrakt kore brucijskog bora imao je potencijalan inhibitorni učinak (P < 0,05) na R. albus samo u najvećoj dozi (1200 μg/mL). Također je imao stimulacijski učinak (P < 0,05) na čiste kulture Fibrobacter succinogenes, a nije utjecao na Megasphaera elsdenii osim u najvećoj dozi. Učinak dviju doza (75 i 375 mg/L) ekstrakta kore brucijskog bora na in vitro mješovite culture i pokazatelje fermentacije u buragu određen je simulacijskom tehnikom (Rusitec). Dodatak ekstrakta kore brucijskog bora doveo je do kvadratnog smanjenja (P < 0,05) broja stanica R. flavefaciens. Nije bilo promjena u proizvodnji ukupnih i pojedinačnih kratkolančanih masnih kiselina (SCFA), omjeru acetata i propionata (C2/C3), ukupnom broju protozoa, buražnom pH i probavljivosti suhe tvari (DMD). Suplementacija objema dozama ekstrakta kore brucijskog bora smanjila je (P < 0,05) koncentracije amonijaka-N. Koncentracija amonijaka-N bila je najniža u skupini s najvećom dozom suplementa (P < 0,05). Zaključujemo da je inhibitorni učinak ekstrakta kore brucijskog bora na neke vrste u čistim kulturama bio jednak onomu u mješovitim buražnim kulturama, a nije bilo stimulacijskog efekta. Manjak inhibitornih učinaka na protozoe i na mnoge Gram-pozitivne buražne bakterije u mješovitim kulturama upućuje na to da njihov mehanizam djelovanja nije jednak onomu kod antibiotika. Premda ekstrakt kore brucijskog bora nije promijenio buražni SCFA, mogao bi poboljšati iskorištavanje proteina u buragu a da pritom ne suprimira mikrobnu fermentaciju

    Design of effective personalised perturbation strategies for enhancing cognitive intervention in Alzheimer’s disease

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    One of the potential and promising adjuvant therapies for Alzheimer’s disease is that of non-invasive transcranial neurostimulation to potentiate cognitive training interventions. Conceptually, this is achieved by driving brain dynamics towards an optimal state for an effective facilitation of cognitive training interventions. However, current neurostimulation protocols rely on experimental trial-and-error approaches that result in variability of symptom improvements and suboptimal progress. Here, we leveraged whole-brain computational modelling by assessing the regional susceptibility towards optimal brain dynamics from Alzheimer’s disease. In practice, we followed the three-part concept of Dynamic Sensitivity Analysis by first understanding empirical differences between healthy controls and patients with mild cognitive impairment and mild dementia due to Alzheimer’s Disease; secondly, by building computational models for all individuals in the mild cognitive impairment and mild dementia cohorts; and thirdly, by perturbing brain regions and assessing the impact on the recovery of brain dynamics to the healthy state (here defined in functional terms, summarised by a measure of metastability for the healthy group). By doing so, we show the importance of key regions, along the anterior-posterior medial line, in driving in-silico improvement of mild dementia and mild cognitive impairment groups. Moreover, this subset consists mainly of regions with high structural nodal degree. Overall, this in-silico perturbational approach could inform the design of stimulation strategies for re-establishing healthy brain dynamics, putatively facilitating effective cognitive interventions targeting the cognitive decline in Alzheimer’s disease

    Hierarchical heterogeneity across human cortex shapes large-scale neural dynamics

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    The large-scale organization of dynamical neural activity across cortex emerges through long-range interactions among local circuits. We hypothesized that large-scale dynamics are also shaped by heterogeneity of intrinsic local properties across cortical areas. One key axis along which microcircuit properties are specialized relates to hierarchical levels of cortical organization. We developed a large-scale dynamical circuit model of human cortex that incorporates heterogeneity of local synaptic strengths, following a hierarchical axis inferred from MRI-derived T1w/T2w mapping, and fit the model using multimodal neuroimaging data. We found that incorporating hierarchical heterogeneity substantially improves the model fit to fMRI-measured resting-state functional connectivity and captures sensory-association organization of multiple fMRI features. The model predicts hierarchically organized high-frequency spectral power, which we tested with resting-state magnetoencephalography. These findings suggest circuit-level mechanisms linking spatiotemporal levels of analysis and highlight the importance of local properties and their hierarchical specialization on the large-scale organization of human cortical dynamics

    The diagnostic and prognostic value of red cell distribution width in cardiovascular disease, current status and prospective

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    The red blood cell distribution width (RDW) is an index of the heterogeneity of circulating red blood cell size, which along with other standard complete blood count (CBC) parameters are used to identify hematological system diseases. Besides hematological disorders, several clinical studies have shown that an increased in the RDW may be associated with other diseases including acute pancreatitis, chronic kidney disease, gastrointestinal disorders, cancer, and of special interest in this review, cardiovascular disease (CVD). The diagnostic and prognostic value of RDW in different CVD (acute coronary syndrome, ischemic cerebrovascular disease, peripheral artery disease, atrial fibrillation, heart failure, and acute ischemic stroke) has been reviewed in this article, to provide an understanding how its measurement may be applied to improve the management of these conditions.Keywords: RDW, Biomarker, Cardiovascular disease
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