The cerebellum is involved in learning and memory of sensory motor skills. However, the way this process takes place in local microcircuits is still unclear. The initial proposal, casted into the ...Motor Learning Theory, suggested that learning had to occur at the parallel fiber–Purkinje cell synapse under supervision of climbing fibers. However, the uniqueness of this mechanism has been questioned, and multiple forms of long-term plasticity have been revealed at various locations in the cerebellar circuit, including synapses and neurons in the granular layer, molecular layer and deep-cerebellar nuclei. At present, more than 15 forms of plasticity have been reported. There has been a long debate on which plasticity is more relevant to specific aspects of learning, but this question turned out to be hard to answer using physiological analysis alone. Recent experiments and models making use of closed-loop robotic simulations are revealing a radically new view: one single form of plasticity is insufficient, while altogether, the different forms of plasticity can explain the multiplicity of properties characterizing cerebellar learning. These include multi-rate acquisition and extinction, reversibility, self-scalability, and generalization. Moreover, when the circuit embeds multiple forms of plasticity, it can easily cope with multiple behaviors endowing therefore the cerebellum with the properties needed to operate as an effective generalized forward controller.
Methotrexate was tethered to multi-walled carbon nanotubes through different cleavable linkers exploiting the ammonium functionalities introduced by 1,3-dipolar cycloaddition reaction of azomethine ...ylides to the nanotubes. The new nanobio-hybrid conjugates were internalized into human breast cancer cells and it was shown that the cytotoxic activity was strongly dependent on the presence and type of linker.
Purpose
To report a case of bilateral thalamic infarction (BTI) presenting as progressive thalamic dementia due to a midline tentorial dAVF (TdAVF) and to provide a systematic review of the ...literature.
Methods
We performed a systematic literature review of previously reported cases of bi-thalamic signal changes due to dAVF considering population characteristics, clinical presentation, imaging findings, treatments, and outcomes.
Results
We found 29 papers from 1985 until 2021 describing 35 cases of BTI dAVF-related. We analysed 36 cases comprehensive of our case report. The mean age was 58.7 years (range 38–79), 91.6% were males (
n
=33). Most cases presented with a subacute syndrome. In 86.1% (
n
=31) of cases a TdAVF was found; 58.3% (
n
=21) were type 2 Borden-Shucart fistulas, the remaining were mostly type 3. In 80.5% (
n
=29), a thrombosed sinus was identified. 33.3% of cases (
n
=12) had bi-thalamic haemorrhages. Endovascular treatment was performed in 83.3% of cases (
n
=30). A total of 75% (
n
=27) of cases had a good recovery.
Conclusions
BTIs due to dAVFs may present with subacute symptoms overlapping with several differential diagnoses. Prompt identification at MRI, before venous drainage failure and bleeding, is crucial for a good prognosis.
Gadolinium-based contrast agent needs time to leak into the extravascular-extracellular space, leak back into the vascular space, and reach an equilibrium state. For this reason, acquisition times of ...<10 min may cause inaccurate estimation of pharmacokinetic parameters. Since no studies have been conducted on the influence of long scan times on DCE-MRI parameters in brain tumors, the aim of this study is to investigate the variation of DCE-MRI-derived kinetic parameters as a function of acquisition time, from 5 to 10 min in brain tumors.
Fifty-two patients with histologically confirmed brain tumors were enrolled in this retrospective study, and examination at 3 T, DCE-MRI, with scan duration of 10 min, was used for retrospective generation of 6 sets of quantitative DCE-MRI maps (K
, V
and K
) from 5 to 10 min. Features were extracted from the DCE-MRI maps in contrast enhancement (CE) volumes. Kruskal-Wallis with post-hoc correction and coefficient of variation (CoV) were used as statistical test to compare DCE-MRI maps obtained from 6 data sets.
p < 0.05.
No differences in K
features in CE volumes between different scan durations. V
, K
features in CE volumes were influenced by different data length. The highest number of significantly different V
and K
features in CE volumes were between 5 min and 10 min (p < 0.013), 5 min and 9 min (p < 0.044), 6 min and 10 min (p < 0.040). CoV of K
was reduced from 5 min to 10 min, going from highly variable (CoV = 0.70) to mildly variable (CoV = 0.42).
K
and V
were time-dependent in brain tumors, so a longer scan time is needed to obtain reliable parameter values. K
was found to be time-independent, as it remains the same in all 6 acquisition times and is the only reliable parameter with short acquisition times.
Conservative transport experiments with layered porous materials (coarse-grained vs. fine-grained) were performed through experimental cylindrical columns to assess the possible occurrence of ...interface processes at the discontinuity between media with different hydrodynamic and hydrodispersive properties, as proposed by some authors in the past based on modelling and experimental results. The outcomes of the present work show that, under certain conditions, the breakthrough curves (BTCs) obtained for flow through the coarse-grained and then through the fine-grained media (CtF) or vice versa (FtC) can differ. More specifically, an asymmetric behaviour is observed for cases when the ratio between the column and grain diameters is small. Moreover, the discrepancies between CtF and FtC BTCs are enhanced for low flow rates and low quantity of injected solute.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Purpose
We present a modified version of the SISCOM procedure that uses interictal PET instead of interictal SPECT for seizure onset zone localization. We called this new nuclear imaging processing ...technique PISCOM (PET interictal subtracted ictal SPECT coregistered with MRI).
Methods
We retrospectively studied 23 patients (age range 4–61 years) with medically refractory epilepsy who had undergone MRI, ictal SPECT, interictal SPECT and interictal FDG PET and who had been seizure-free for at least 2 years after surgical treatment. FDG PET images were reprocessed (rFDG PET) to assimilate SPECT features for image subtraction. Interictal SPECT and rFDG PET were compared using statistical parametric mapping (SPM). PISCOM and SISCOM images were evaluated visually and using an automated volume of interest-based analysis. The results of the two studies were compared with each other and with the known surgical resection site.
Results
SPM showed no significant differences in cortical activity between SPECT and rFDG PET images. PISCOM and SISCOM showed equivalent results in 17 of 23 patients (74%). The seizure onset zone was successfully identified in 19 patients (83%) by PISCOM and in 17 (74%) by SISCOM: in 15 patients (65%) the two techniques showed concordant successful results. The volume of interest-based analysis showed no significant differences between PISCOM and SISCOM in identifying the extension of the seizure onset zone. However, PISCOM showed a lower amount of indeterminate activity due to propagation, background or artefacts.
Conclusion
Preliminary findings of this initial proof-of-concept study suggest that perfusion and glucose metabolism in the cerebral cortex can be correlated and that PISCOM may be a valid technique for identification of the seizure onset zone. However, further studies are needed to validate these results.
CT perfusion (CTP) is used in patients with anterior circulation acute ischemic stroke (AIS) for predicting the final infarct volume (FIV). Tandem occlusion (TO), involving both intracranial large ...vessels and the ipsilateral cervical internal carotid artery could generate hemodynamic changes altering perfusion parameters. Our aim is to evaluate the accuracy of CTP in the prediction of the FIV in TOs.
consecutive patients with AIS due to middle cerebral artery occlusion, referred to a tertiary stroke center between March 2019 and January 2021, with an automated CTP and successful recanalization (mTICI = 2b - 3) after endovascular treatment were retrospectively included in the tandem group (TG) or in the control group (CG). Patients with parenchymal hematoma type 2, according to ECASS II classification of hemorrhagic transformations, were excluded in a secondary analysis. Demographic, clinical, radiological, time intervals, safety, and outcome measures were collected.
among 319 patients analyzed, a comparison between the TG (N = 22) and CG (n = 37) revealed similar cerebral blood flow (CBF) > 30% (29.50 ± 32.33 vs. 15.76 ± 20.93
= 0.18) and FIV (54.67 ± 65.73 vs. 55.14 ± 64.64
= 0.875). Predicted ischemic core (PIC) and FIV correlated in both TG (tau = 0.761,
< 0.001) and CG (tau = 0.315,
= 0.029). The Bland-Altmann plot showed agreement between PIC and FIV for both groups, mainly in the secondary analysis.
automated CTP could represent a good predictor of FIV in patients with AIS due to TO.
Polyphenols are bioactive compounds with several anticarcinogenic activities; however, human data regarding associations with thyroid cancer (TC) is still negligible. Our aim was to evaluate the ...association between intakes of total, classes and subclasses of polyphenols and risk of differentiated TC and its main subtypes, papillary and follicular, in a European population. The European Prospective Investigation into Cancer and Nutrition cohort included 476,108 men and women from 10 European countries. During a mean follow‐up of 14 years, there were 748 incident differentiated TC cases, including 601 papillary and 109 follicular tumors. Polyphenol intake was estimated at baseline using validated center/country‐specific dietary questionnaires and the Phenol‐Explorer database. In multivariable‐adjusted Cox regression models, no association between total polyphenol and the risks of overall differentiated TC (HRQ4 vs. Q1 = 0.99, 95% confidence interval CI 0.77–1.29), papillary (HRQ4 vs. Q1 = 1.06, 95% CI 0.80–1.41) or follicular TC (HRQ4 vs. Q1 = 1.10, 95% CI 0.55–2.22) were found. No associations were observed either for flavonoids, phenolic acids or the rest of classes and subclasses of polyphenols. After stratification by body mass index (BMI), an inverse association between the intake of polyphenols (p‐trend = 0.019) and phenolic acids (p‐trend = 0.007) and differentiated TC risk in subjects with BMI ≥ 25 was observed. In conclusion, our study showed no associations between dietary polyphenol intake and differentiated TC risk; although further studies are warranted to investigate the potential protective associations in overweight and obese individuals.
What's new?
Polyphenols are secondary plant metabolites with health protective properties but whether a diet rich in polyphenols protects from thyroid cancer has not been conclusively explored. In this large prospective study, no associations were observed between dietary polyphenol intake and differentiated thyroid cancer risk. The authors recommend further studies to investigate potential associations specifically in overweight and obese individuals.
Biallelic variants of the gene encoding for the zinc‐finger protein 142 (ZNF142) have recently been associated with intellectual disability (ID), speech impairment, seizures, and movement disorders ...in nine individuals from five families. In this study, we obtained phenotype and genotype information of 26 further individuals from 16 families. Among the 27 different ZNF142 variants identified in the total of 35 individuals only four were missense. Missense variants may give a milder phenotype by changing the local structure of ZF motifs as suggested by protein modeling; but this correlation should be validated in larger cohorts and pathogenicity of the missense variants should be investigated with functional studies. Clinical features of the 35 individuals suggest that biallelic ZNF142 variants lead to a syndromic neurodevelopmental disorder with mild to moderate ID, varying degrees of delay in language and gross motor development, early onset seizures, hypotonia, behavioral features, movement disorders, and facial dysmorphism. The differences in symptom frequencies observed in the unpublished individuals compared to those of published, and recognition of previously underemphasized facial features are likely to be due to the small sizes of the previous cohorts, which underlines the importance of larger cohorts for the phenotype descriptions of rare genetic disorders.
Zinc‐finger protein 142, encoded by ZNF142, belongs to a family transcriptional repressors that recruit chromatin remodeling proteins to DNA. They are widely expressed and are important for numerous processes such as development, cell differentiation and proliferation, and apoptosis. Zn2+ ions (gray) and three modellable missense variants (yellow) are depicted as spheres.
We describe the case of a newborn girl who displayed association of aortic atresia and interrupted aortic arch, with retrograde flow in ascending aorta, through extracranial anastomoses between ...vertebral arteries (arisen from descending aorta) and external carotids.
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