Advanced MR imaging in Lhermitte-Duclos disease: moving closer to pathology and pathophysiology

Introduction Lhermitte-Duclos disease (LDD, dysplastic gangliocytoma) is an extremely rare cerebellar lesion of uncertain etiology. The debate as to whether it constitutes a neoplastic, malformative, or hamartomatous lesion is still continuing. In this report we explore the usefulness of susceptibility-weighted imaging (SWI), diffusion weighted imaging (DWI), perfusion imaging, and chemical shift imaging (CSI) in demonstrating the pathology and pathophysiology in two patients with LDD. Methods MR imaging of the brain and the cervicodorsal spine was performed on a 1.5-T scanner in a 47-year-old woman presenting with numbness and paresthesia of both upper and lower limbs, and in a 17-year-old male with right frontal headache associated with neck pain. Results Routine imaging in the first patient showed a left-side cerebellar mass with characteristic ’tiger-striped’ thick folia associated with Chiari I malformation, tonsillar herniation and cervicodorsal syringomyelia and in the second patient a right cerebellar mass with similar findings. The SWI demonstrated the characteristic deep running veins between the folia, which is thought to be the cause for vascular contrast enhancement. Diffusion showed a T2 shine-through effect with mild increased diffusivity, and perfusion showed increase in relative cerebral blood volume, relative cerebral blood flow, and mean transit time in the lesion. MR spectroscopy demonstrated reduction in metabolites and a prominent lactate peak in both the patients. The pathological and pathophysiological significance of these findings is discussed. Conclusion MRI with the newer imaging capabilities can demonstrate the pathology and pathophysiology in Lhermitte-Duclos disease better. SWI helps in detecting the veins around the thickened folia.     

Site of attachment of retinal in bacteriorhodopsin.

The identity of the lysine residue in bacteriorhodopsin to which the chromophore, retinal, is attached as a Schiff's base has been reinvestigated. Retinal is now shown to be linked to lysine-216 and not lysine-41, as had been concluded previously. The retinal in purple membrane was replaced by [15-3H]retinal, the Schiff's base linkage was reduced with NaBH4 while the sample was illuminated, and the resulting [retinyl-3H]bacterio-opsin was cleaved with CNBr. The radioactivity was present exclusively in the COOH-terminal peptide (amino acids 210--248). Sequence analysis showed that the [3H]retinal was attached to lysine-216. The same site was labeled when purple membrane was reduced with NaBH4 in the light at pH greater than 10 or at pH 8 and when membranes modified with ether or solubilized with hexadecyltrimethylammonium bromide were reduced in the dark. Our finding places of Schiff's base linkage close to the midpoint of the putative membrane-spanning alpha-helix that is directly connected to the COOH terminus of bacteriorhodopsin.     

A case of post‐leptospirosis autoimmune epilepsy presenting with sleep‐related hypermotor seizures

This video‐illustrated case report concerns a 49‐year‐old woman who presented with sleep‐related hypermotor seizures. The antecedent history of leptospirosis, high frequency of new‐onset seizures, presence of an unclassified anti‐neuronal antibody, and dramatic response to steroids strongly supported post‐infectious immune‐mediated pathogenesis in our patient. To the best of our knowledge, post‐leptospirosis autoimmune epilepsy presenting as sleep‐related hypermotor seizures has not hitherto been reported. [Published with video sequence on www.epilepticdisorders.com ].     

Does prophylactic sotalol and magnesium decrease the incidence of atrial fibrillation following coronary artery bypass surgery: a propensity-matched analysis

Background  

Atrial fibrillation can occur in up to 40% of patients undergoing coronary surgery.     

Thoracic surgical management of colorectal lung metastases: a questionnaire survey of members of the Society for Cardiothoracic Surgery in great Britain and Ireland

Introduction

Distant metastases to liver and lung are not uncommon in colorectal cancer. Resection of metastases is accepted widely as the standard of care. However, there is no firm evidence base for this. This questionnaire survey was carried out to assess the current practice preferences of cardiothoracic surgeons in Great Britain and Ireland.

Methods

An online questionnaire survey was emailed to cardiothoracic surgeons in Great Britain and Ireland. The survey was live for 12 weeks. Responses were collated with SurveyMonkey^®.

Results

Overall, there were 75 respondents. The majority (83%) indicated thoracic surgery as a specialist interest. Almost all (99%) used thoracic computed tomography (CT) for staging; 70% added liver CT and 51% added pelvic CT. Fluorodeoxyglucose positron emission tomography was used by 86%. The most frequent indication for pulmonary resection (97%) was solitary lung metastasis without extrathoracic disease. Video assisted thoracoscopic surgery (VATS) was used by 85%. In addition, thoracotomy was used by 96%. A third (33%) used radiofrequency ablation. Synchronous liver and lung resection was contraindicated for 83% of respondents. Over three-quarters (77%) thought that scientific equipoise exists presently for lung resection for colorectal lung metastases but only 21% supported a moratorium on this type of surgery until further evidence becomes available.

Conclusions

The results confirm that the majority of respondents use conventional cross-sectional imaging and either VATS or formal thoracotomy for resection. The results emphasise the continuing need for formal randomised trials to provide evidence of any survival benefit from pulmonary metastasectomy for colorectal lung metastases.     

Validation of an Electronic Medical Record–Based Algorithm for Identifying Posttraumatic Stress Disorder in U.S. Veterans

We developed an algorithm for identifying U.S. veterans with a history of posttraumatic stress disorder (PTSD), using the Department of Veterans Affairs (VA) electronic medical record (EMR) system. This work was motivated by the need to create a valid EMR‐based phenotype to identify thousands of cases and controls for a genome‐wide association study of PTSD in veterans. We used manual chart review (n = 500) as the gold standard. For both the algorithm and chart review, three classifications were possible: likely PTSD, possible PTSD, and likely not PTSD. We used Lasso regression with cross‐validation to select statistically significant predictors of PTSD from the EMR and then generate a predicted probability score of being a PTSD case for every participant in the study population (range: 0–1.00). Comparing the performance of our probabilistic approach (Lasso algorithm) to a rule‐based approach (International Classification of Diseases [ICD] algorithm), the Lasso algorithm showed modestly higher overall percent agreement with chart review than the ICD algorithm (80% vs. 75%), higher sensitivity (0.95 vs. 0.84), and higher accuracy (AUC = 0.95 vs. 0.90). We applied a 0.7 probability cut‐point to the Lasso results to determine final PTSD case‐control status for the VA population. The final algorithm had a 0.99 sensitivity, 0.99 specificity, 0.95 positive predictive value, and 1.00 negative predictive value for PTSD classification (grouping possible PTSD and likely not PTSD) as determined by chart review. This algorithm may be useful for other research and quality improvement endeavors within the VA.     

Can diffusion tensor metrics help in preoperative grading of diffusely infiltrating astrocytomas? A retrospective study of 36 cases

Introduction  

Diffusion weighted imaging and diffusion tensor imaging (DTI) give information about the amount and directionality of water diffusion occurring in a given tissue. Here we study the role of diffusion tensor metrics including fractional anisotropy (FA) and spherical anisotropy (CS) in preoperative grading of diffusely infiltrating astrocytomas.     

Does postural stability affect grasping?

We examined whether challenging upright stance influences the execution of a grasping task. Participants reached to grasp a small sphere while standing either on a stable surface or on foam. Before reaching for the sphere, participants exhibited more body sway and greater fluctuations in the centre of pressure when standing on foam. While reaching for the sphere, the overall body posture changed less when standing on foam than when standing on the stable surface. The digits’ and wrist's movements towards the sphere were no different when standing on foam than when standing on the stable surface. Presumably, the redundancy in the way movements can be performed is exploited to choose the most suitable changes in joint angles to achieve the desired movements of the digits under the prevailing conditions.