No abstract

Objective Mesial temporal lobe epilepsy (MTLE) is a network disorder. We aimed to quantify the white matter alterations in the temporal lobe of MTLE patients with hippocampal sclerosis (MTLE‐HS) by using magnetic resonance fingerprinting (MRF), a novel imaging technique, which allows simultaneous measurements of multiple parameters with a single acquisition. Methods We consecutively recruited 27 unilateral MTLE‐HS patients and 22 healthy controls. Measurements including T1, T2, and PD values in the temporopolar white matter and temporal stem were recorded and analyzed. Results We found increased T2 value in both sides, and increased T1 value in the ipsilateral temporopolar white matter of MTLE‐HS patients, as compared with healthy controls. The T1 and T2 values were higher in the ipsilateral than the contralateral side. In the temporal stem, increased T1 and T2 values in the ipsilateral side of the MTLE‐HS patients were also observed. Only increased T2 values were observed in the contralateral temporal stem. No significant differences in PD values were observed in either the temporopolar white matter or temporal stem of the MTLE‐HS patients. Correlation analysis revealed that T1 and T2 values in the ipsilateral temporopolar white matter were negatively correlated with the age at epilepsy onset. Interpretation By using MRF, we were able to assess the alterations of T1 and T2 in the temporal lobe white matter of MTLE‐HS patients. MRF could be a promising imaging technique in identifying mild changes in MTLE patients, which might optimize the pre‐surgical evaluation and therapeutic interventions in these patients.

Efficient genome editing is a prerequisite of genetic engineering in synthetic biology, which has been recently achieved by the powerful CRISPR/Cas9 system. However, the toxicity of Cas9, due to its abundant intracellular expression, has impeded its extensive applications. Here we constructed a genetic cassette with triple controls of Cas9 activities at transcriptional, translational and protein levels, together with over-expression of the ATP synthase β-subunit AtpD, for the efficient genome editing in Streptomyces. By deletion of actII-ORF4 in Streptomyces coelicolor as a model, we found that constitutive expression of cas9 had about 90% editing efficiency but dramatically reduced transformation efficiency by 900-fold. However, triple controls of Cas9 under non-induction conditions to reduce its activity increased transformation efficiency over 250-fold, and had about 10% editing efficiency if combined with atpD overexpression. Overall, our strategy accounts for about 30-fold increased possibility for successful genome editing under the non-induction condition. In addition, about 80% editing efficiency was observed at the actII-ORF4 locus after simultaneous induction with thiostrepton, theophylline and blue light for Cas9 activity reconstitution. This improved straightforward efficient genome editing was also confirmed in another locus redD. Thus, we developed a new strategy for efficient genome editing, and it could be readily and widely adaptable to other Streptomyces species to improve genetic manipulation for rapid strain engineering in Streptomyces synthetic biology, due to the highly conserved genetic cassettes in this genus.

is supported by the China Scholarship Council for a 2-year study at Massachusetts General Hospital Purpose: To rapidly obtain high isotropic-resolution T 2 maps with whole-brain coverage and high geometric fidelity. Methods: A T 2 blip-up/down EPI acquisition with generalized slice-dithered enhanced resolution (T 2 -BUDA-gSlider) is proposed. A RF-encoded multi-slab spinecho (SE) EPI acquisition with multiple TEs was developed to obtain high SNR efficiency with reduced TR. This was combined with an interleaved 2-shot EPI acquisition using blip-up/down phase encoding. An estimated field map was incorporated into the joint multi-shot EPI reconstruction with a structured low rank constraint to achieve distortion-free and robust reconstruction for each slab without navigation. A Bloch simulated subspace model was integrated into gSlider reconstruction and used for T 2 quantification. Results: In vivo results demonstrated that the T 2 values estimated by the proposed method were consistent with gold standard spin-echo acquisition. Compared to the reference 3D fast spin echo (FSE) images, distortion caused by off-resonance and eddy current effects were effectively mitigated.How to cite this article: Cao X, Wang K, Liao C, et al. Efficient T 2 mapping with blip-up/down EPI and gSlider-SMS (T 2 -BUDA-gSlider).

The homeostasis of various metabolites is impaired in epilepsy secondary to the tuberous sclerosis complex (TSC). Chemical exchange saturation transfer (CEST) imaging is an emerging molecular MRI technique that can detect various metabolites and proteins in vivo. However, the role of CEST imaging for TSC‐associated epilepsy has not been assessed. Here, we aim to investigate the feasibility of applying CEST imaging to TSC‐associated epilepsy, optimize the CEST acquisition parameters, and provide an analysis method for exploring the dominant molecular contributors to the CEST signal measured. Nine TSC epilepsy patients were scanned on a 3‐T MRI system. The CEST saturation frequencies were swept from −6 to 6 ppm with 12 different combinations of saturation power (4, 3, 2 and 1 μT) and duration (1000, 700 and 400 ms). Furthermore, a two‐stage simulation method based on the seven‐pool Bloch‐McConnell model was proposed to assess the contribution of each exchangeable pool to the CEST signal in normal‐appearing white matter and cortical tubers, which avoided the complexity and uncertainty of full Bloch‐McConnell fitting. The results showed that under the optimal saturation duration of 1000 ms, the greatest contrast between tubers and normal tissues occurred around 3, 2.5, 1.75 and 3.5 ppm for B1 of 4, 3, 2 and 1 μT, respectively. At the optimal frequency offsets, the CEST values of tubers were significantly higher than those in the normal brain tissues (P < 0.01). Furthermore, the two‐stage analysis suggested that the amine pool played a dominant role in yielding the contrast between cortical tubers and normal tissues. These results indicate that CEST MRI may serve as a potentially useful tool for identifying tubers in TSC, and the two‐stage analysis method may provide a route for investigating the molecular contributions to the CEST contrast in biological tissues.

This study expands the clinical and genetic spectrums of Chinese patients with paroxysmal kinesigenic dyskinesia and infantile convulsions and choreoathetosis. No clear genotype-phenotype correlation between the age at onset and the types of mutations has been determined.

Objective To investigate whether the early administration of intravenous second‐line immunotherapy correlates with improved long‐term cognition and the potential mechanisms via imaging in adult patients with moderate‐to‐severe anti‐N‐methyl‐D‐aspartate (NMDA) receptor encephalitis. Methods Sixteen adult patients with moderate‐to‐severe anti‐NMDA receptor encephalitis past the acute stage and 15 healthy controls (HCs) performed a set of comprehensive neuropsychological tests, and underwent a resting‐state fMRI study to analyze resting state functional connectivity (FC). In addition, correlation analyses were performed between hippocampal FC and cognitive performance. All patients were received intravenous first‐line immunotherapy, and nine of them were also given intravenous second‐line immunotherapy within 3 months of disease onset. Results The patients who only received first‐line immunotherapy showed significant verbal episodic memory impairments compared with HCs and those who received second‐line immunotherapy, while no significant differences were noted between the patients with second‐line immunotherapy and the HCs. In line with the results of neuropsychological tests, significant changes in bilateral hippocampal FC were observed in the patients who only received first‐line immunotherapy compared with both HCs and those who received second‐line immunotherapy. However, no significant differences in hippocampal FC were observed in the patients with second‐line immunotherapy compared with the HCs. Importantly, hippocampal‐medial prefrontal cortex (mPFC) connectivity positively correlated with memory performance. Interpretation In the long term, early administration of intravenous second‐line immunotherapy may be associated with more favorable verbal episodic memory outcomes in patients with moderate‐to‐severe anti‐NMDA receptor encephalitis. These results may provide some evidence and guidance for the use of immunotherapy in this population.

No abstract