87 research outputs found

    Imaging Structural Connections of the Brain in Epilepsy

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    Introduction Temporal lobe epilepsy (TLE) is the most common cause of medically intractable partial epilepsy in adults. For many patients, anterior temporal lobe resection (ATLR) is an effective means of treatment, but can cause a significant decline in language or memory function, and visual field deficits. Diffusion tensor imaging and tractography is an MRI technique that can be used to probe white matter structure, and delineate the white matter tracts relevant to vision, language, and memory function. Aims We aimed to use diffusion MRI to increase understanding of the causes and consequences of TLE, and identify patients who are at risk of language, and visual impairment after surgery. Methods and Analysis Techniques Healthy controls, and patients with TLE were scanned pre- and post operatively using 3T MRI. All patients in the study underwent a comprehensive pre- and post-surgical evaluation including clinical, MRI, video-EEG, and neuropsychological assessment. Whole brain analysis of both pre-, and post-operative diffusion MRI was carried out. Tractography was used to assess white matter relevant to memory, language and vision. Correlation analysis of white matter data, and neuropsychological and clinical variables was carried out using the statistical software package, SPSS. Results and Discussion This thesis demonstrates the widespread changes in white matter microstructure present in patients with TLE, and the relationship between medial temporal lobe connections and memory function. It demonstrates how white matter microstructure changes after anterior temporal lobe resection, and how this information can be used to aid prediction of post-operative language deficits in patients. It concludes by showing that tractography can be used to predict postoperative visual field deficits. Conclusion Diffusion Mill can be used to increase our understanding of the causes and consequences of TLE, and to improve pre-surgical planning

    Imaging memory in temporal lobe epilepsy: predicting the effects of temporal lobe resection

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    Functional magnetic resonance imaging can demonstrate the functional anatomy of cognitive processes. In patients with refractory temporal lobe epilepsy, evaluation of preoperative verbal and visual memory function is important as anterior temporal lobe resections may result in material specific memory impairment, typically verbal memory decline following left and visual memory decline after right anterior temporal lobe resection. This study aimed to investigate reorganization of memory functions in temporal lobe epilepsy and to determine whether preoperative memory functional magnetic resonance imaging may predict memory changes following anterior temporal lobe resection. We studied 72 patients with unilateral medial temporal lobe epilepsy (41 left) and 20 healthy controls. A functional magnetic resonance imaging memory encoding paradigm for pictures, words and faces was used testing verbal and visual memory in a single scanning session on a 3T magnetic resonance imaging scanner. Fifty-four patients subsequently underwent left (29) or right (25) anterior temporal lobe resection. Verbal and design learning were assessed before and 4 months after surgery. Event-related functional magnetic resonance imaging analysis revealed that in left temporal lobe epilepsy, greater left hippocampal activation for word encoding correlated with better verbal memory. In right temporal lobe epilepsy, greater right hippocampal activation for face encoding correlated with better visual memory. In left temporal lobe epilepsy, greater left than right anterior hippocampal activation on word encoding correlated with greater verbal memory decline after left anterior temporal lobe resection, while greater left than right posterior hippocampal activation correlated with better postoperative verbal memory outcome. In right temporal lobe epilepsy, greater right than left anterior hippocampal functional magnetic resonance imaging activation on face encoding predicted greater visual memory decline after right anterior temporal lobe resection, while greater right than left posterior hippocampal activation correlated with better visual memory outcome. Stepwise linear regression identified asymmetry of activation for encoding words and faces in the ipsilateral anterior medial temporal lobe as strongest predictors for postoperative verbal and visual memory decline. Activation asymmetry, language lateralization and performance on preoperative neuropsychological tests predicted clinically significant verbal memory decline in all patients who underwent left anterior temporal lobe resection, but were less able to predict visual memory decline after right anterior temporal lobe resection. Preoperative memory functional magnetic resonance imaging was the strongest predictor of verbal and visual memory decline following anterior temporal lobe resection. Preoperatively, verbal and visual memory function utilized the damaged, ipsilateral hippocampus and also the contralateral hippocampus. Memory function in the ipsilateral posterior hippocampus may contribute to better preservation of memory after surgery

    Synthesis and Characterization of Conjugated/Cross-Conjugated Benzene-Bridged Boron Difluoride Formazanate Dimers

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    One of the most common strategies for the production of molecular materials with optical properties in the far-red/near-IR regions of the electromagnetic spectrum is their incorporation into dimeric architectures. In this paper, we describe the synthesis and characterization (1H, 11B, 13C and 19F NMR spectroscopy, IR and UV-Vis absorption and emission spectroscopy, mass spectrometry and X-ray crystallography) of the first examples of boron difluoride (BF2) formazanate dimers. Specifically, the properties of meta- and para-substituted benzene-bridged dimers p-10 and m-10 were compared to closely related boron difluoride triphenyl formazanate complex 11 in order to assess the effect of electronic conjugation and cross conjugation on their light absorption/emission and electrochemical properties. While the properties of cross-conjugated dimer m-10 did not differ significantly from those of monomer 11, conjugated dimer p-10 exhibited red-shifted absorption and emission maxima and was easier to reduce electrochemically to its bis radical anion and bis dianion form compared to monomer 11. Both dimers are weakly emissive in the far-red/near-IR and exhibited large Stokes shifts (\u3e 110 nm, 3318 cm−1). Unlike a closely related para-substituted benzene-bridged boron dipyrromethene (BODIPY) dimer, the emission quantum yields measured for the BF2 formazanate dimers exceeded those observed for monomeric analogues

    Efficacy and safety of secukinumab for the treatment of severe ABCA12 deficiency‐related ichthyosis in a child

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    Summary Background Patients with severe autosomal recessive congenital ichthyosis (ARCI) show a T helper 17/interleukin 17 (Th17/IL17) skewing in their skin and serum, resembling the inflammatory profile of psoriatic patients. Secukinumab, an IL‐17A inhibitor, has shown clinical efficacy in patients with moderate‐to‐severe plaque psoriasis. Aims To test the clinical efficacy and safety of secukinumab in a paediatric patient with ATP‐binding cassette subfamily A member 12 deficiency‐related severe erythrodermic ARCI. Materials & Methods 6‐months therapeutic trial. During the first 4‐weeks induction period, the patient received weekly subcutaneous injections of 150 mg secukinumab (five injections in total). During the following 20‐weeks maintenance period, the patient was given a subcutaneous injection of 150 mg secukinumab every 4 weeks. Result & Discussion After the 6‐months therapy period, there was a 48% reduction from the baseline Ichthyosis‐Area‐Severity‐Index (‐Erythema/‐Scaling) score. The treatment was well tolerated. Moreover, cytokine analysis revealed a reduction of keratinocyte‐derived proinflammatory cytokines and an abrogation of Th17‐skewing during therapy. Conclusion Further studies are needed to evaluate the effects of the use of IL‐17A inhibition in ARCI patients

    PAX6, brain structure and function in human adults: Advanced MRI in aniridia

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    Objective PAX6 is a pleiotropic transcription factor essential for the development of several tissues including the eyes, central nervous system, and some endocrine glands. Recently it has also been shown to be important for the maintenance and functioning of corneal and pancreatic tissues in adults. We hypothesized that PAX6 is important for the maintenance of brain integrity in humans, and that adult heterozygotes may have abnormalities of cortical patterning analogous to those found in mouse models. Methods We used advanced magnetic resonance imaging techniques, including surface-based morphometry and region-of-interest analysis in adult humans heterozygously mutated for PAX6 mutations (n = 19 subjects and n = 21 controls). Using immunohistochemistry, we also studied PAX6 expression in the adult brain tissue of healthy subjects (n = 4) and patients with epilepsy (n = 42), some of whom had focal injuries due to intracranial electrode track placement (n = 17). Results There were significant reductions in frontoparietal cortical area after correcting for age and intracranial volume. A greater decline in thickness of the frontoparietal cortex with age, in subjects with PAX6 mutations compared to controls, correlated with age-corrected, accelerated decline in working memory. These results also demonstrate genotypic effects: those subjects with the most severe genotypes have the most widespread differences compared with controls. We also demonstrated significant increases in PAX6-expressing cells in response to acute injury in the adult human brain. Interpretation These findings suggest a role for PAX6 in the maintenance and consequent functioning of the adult brain, homologous to that found in other tissues. This has significant implications for the understanding and treatment of neurodegenerative diseases
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