Dopamine neurotransmitter and its receptors play a critical role in the cell signaling process responsible for information transfer in neurons functioning in the nervous system. Development of improved therapeutics for such disorders as Parkinson's disease and schizophrenia would be significantly enhanced with the availability of the 3D structure for the dopamine receptors and of the binding site for dopamine and other agonists and antagonists. We report here the 3D structure of the long isoform of the human D2 dopamine receptor, predicted from primary sequence using firstprinciples theoretical and computational techniques (i.e., we did not use bioinformatic or experimental 3D structural information in predicting structures). The predicted 3D structure is validated by comparison of the predicted binding site and the relative binding affinities of dopamine, three known dopamine agonists (antiparkinsonian), and seven known antagonists (antipsychotic) in the D2 receptor to experimentally determined values. These structures correctly predict the critical residues for binding dopamine and several antagonists, identified by mutation studies, and give relative binding affinities that correlate well with experiments. The predicted binding site for dopamine and agonists is located between transmembrane (TM) helices 3, 4, 5, and 6, whereas the best antagonists bind to a site involving TM helices 2, 3, 4, 6, and 7 with minimal contacts to TM helix 5. We identify characteristic differences between the binding sites of agonists and antagonists.W ith the implication of G protein-coupled receptor (GPCR) in many diseases (1, 2), the need to solve the highresolution 3D structure of this class of integral membrane proteins to enable structure-based drug design is an important problem in structural biology. Despite the importance of solving the structure of the GPCRs, the only experimental 3D structure available for a GPCR is bovine rhodopsin. This lack of structures is because the GPCRs are bound to the membrane, making it difficult to express in sufficient quantities for crystallization.To provide structural and ligand binding information on GPCRs, we have been developing first-principles computational techniques for predicting the 3D structure of GPCRs using only the amino acid sequence (MembStruk) and for predicting binding site and binding energy of various ligands to GPCRs (HierDock). Using these techniques, we have reported the structure of olfactory receptors (3, 4), bovine rhodopsin (4, 5), and other GPCRs (4). Dopamine neurotransmitter plays a critical role in cellular signaling processes responsible for information transfer in neurons functioning in the nervous system (6, 7). Dopamine receptors (DR) belong to the superfamily of GPCRs, and to date there are five reported sequences for the human DR with multiple isoforms for each. The DRs may be subdivided based on their pharmacological behavior into the D1-like and the D2-like subfamilies, and these are ideal targets for treating schizophrenia and Parkinson's disease; th...

OBJECTIVE This study evaluated the utility, specificity, and sensitivity of intraoperative confocal laser endomicroscopy (CLE) to provide diagnostic information during resection of human brain tumors. METHODS CLE imaging was used in the resection of intracranial neoplasms in 74 consecutive patients (31 male; mean age 47.5 years; sequential 10-month study period). Intraoperative in vivo and ex vivo CLE was performed after intravenous injection of fluorescein sodium (FNa). Tissue samples from CLE imaging–matched areas were acquired for comparison with routine histological analysis (frozen and permanent sections). CLE images were classified as diagnostic or nondiagnostic. The specificities and sensitivities of CLE and frozen sections for gliomas and meningiomas were calculated using permanent histological sections as the standard. RESULTS CLE images were obtained for each patient. The mean duration of intraoperative CLE system use was 15.7 minutes (range 3–73 minutes). A total of 20,734 CLE images were correlated with 267 biopsy specimens (mean number of images/biopsy location, in vivo 84, ex vivo 70). CLE images were diagnostic for 45.98% in vivo and 52.97% ex vivo specimens. After initiation of CLE, an average of 14 in vivo images and 7 ex vivo images were acquired before identification of a first diagnostic image. CLE specificity and sensitivity were, respectively, 94% and 91% for gliomas and 93% and 97% for meningiomas. CONCLUSIONS CLE with FNa provided intraoperative histological information during brain tumor removal. Specificities and sensitivities of CLE for gliomas and meningiomas were comparable to those for frozen sections. These data suggest that CLE could allow the interactive identification of tumor areas, substantially improving intraoperative decisions during the resection of brain tumors.

H istorically, the surgical management of intrinsic brainstem lesions has been controversial. The surgical extirpation of focal gliomas, cavernous malformations, or hemangioblastomas within the brainstem has caused heated discussions in scientific meetings and the literature. In 1939, Bailey et al. 3 declared this subject to be a pessimistic chapter in neurosurgery; 30 years later, Matson and Ingraham 26 would still claim such lesions were inoperable. However, in 1971, Lassiter et al. 25 were among the first to advocate surgical intervention. By 1986, Epstein and McCleary reported that surgery was feasible with reasonable morbidity and mortality.15 Concurrent with Epstein and McCleary's report, Raimondi would rationally state that to have the child merely survive (i.e., with severe neurological deficits) is no justification for surgery. 33 The development and improvement of complex skull base surgical approaches and incremental advances in neuroimaging, parallel to image-guided surgery, allowed a few authors to safely and effectively resect lesions in the brainstem. 5,23,32Knowledge of different skull base exposures, gained through laboratory dissections, allows neurosurgeons to approach lesions in the brainstem. Nevertheless, the brainstem, roughly the size of the human thumb, contains a rich concentration of nuclei and fibers in a small sectional area, resulting in a high likelihood of morbidity after manipulation. Awareness of the main safe entry zones on the brainstem is key to reducing morbidity for any lesion that does not emerge to the pial or ependymal surface. Such zones represent entry points and trajectories where eloquent structures and perforators are sparse and where a neurotomy would cause the least possible damage.abbreviatioNs CN = cranial nerve; mini-OZ = mini-modified orbitozygomatic approach; PCA = posterior cerebral artery; P 2 P = posterior P 2 ; SCA = superior cerebellar artery; TAPS = transanterior perforating substance. obJective The aim of this study was to enhance the planning and use of microsurgical resection techniques for intrinsic brainstem lesions by better defining anatomical safe entry zones. methods Five cadaveric heads were dissected using 10 surgical approaches per head. Stepwise dissections focused on the actual areas of brainstem surface that were exposed through each approach and an analysis of the structures found, as well as which safe entry zones were accessible via each of the 10 surgical windows. results Thirteen safe entry zones have been reported and validated for approaching lesions in the brainstem, including the anterior mesencephalic zone, lateral mesencephalic sulcus, intercollicular region, peritrigeminal zone, supratrigeminal zone, lateral pontine zone, supracollicular zone, infracollicular zone, median sulcus of the fourth ventricle, anterolateral and posterior median sulci of the medulla, olivary zone, and lateral medullary zone. A discussion of the approaches, anatomy, and limitations of these entry zones is included. coNclusioNs A detailed understanding...

OBJECTIVEEnhanced recovery after surgery (ERAS) is a multidimensional approach to improving the care of surgical patients using subspecialty- and procedure-specific evidence-based protocols. The literature provides evidence of the benefits of ERAS implementation, which include expedited functional recovery, decreased postoperative morbidity, reduced costs, and improved subjective patient experience. Although extensively examined in other surgical areas, ERAS principles have been applied to spine surgery only in recent years. The authors examine studies investigating the application of ERAS programs to patients undergoing spine surgery.METHODSThe authors conducted a systematic review of the PubMed and MEDLINE databases up to November 20, 2018.RESULTSTwenty full-text articles were included in the qualitative analysis. The majority of studies were retrospective reviews of nonrandomized data sets or qualitative investigations lacking formal control groups; there was 1 protocol for a future randomized controlled trial. Most studies demonstrated reduced lengths of stay and no increase in rates of readmissions or complications after introduction of an ERAS pathway.CONCLUSIONSThese introductory studies demonstrate the potential of ERAS protocols, when applied to spine procedures, to reduce lengths of stay, accelerate return of function, minimize postoperative pain, and save costs.

Ten ongoing studies designed to test the possibility that extracellular RNAs may serve as biomarkers in human disease are described. These studies, funded by the NIH Common Fund Extracellular RNA Communication Program, examine diverse extracellular body fluids, including plasma, serum, urine and cerebrospinal fluid. The disorders studied include hepatic and gastric cancer, cardiovascular disease, chronic kidney disease, neurodegenerative disease, brain tumours, intracranial haemorrhage, multiple sclerosis and placental disorders. Progress to date and the plans for future studies are outlined.

Highlights d In human brain, the synaptic protein NLGN4 is primarily expressed in cerebral cortex d Unlike in mouse, human NLGN4 protein preferentially localizes to glutamatergic synapses d NLGN4 gain of function induces an excitatory synaptic phenotype in human neurons d R704C increases excitatory synapse density, synapse transmission, and AMPAR affinity

We examined the extracellular vesicle (EV) and RNA composition of pooled normal cerebrospinal fluid (CSF) samples and CSF from five major neurological disorders: Alzheimer’s disease (AD), Parkinson’s disease (PD), low-grade glioma (LGG), glioblastoma multiforme (GBM), and subarachnoid haemorrhage (SAH), representing neurodegenerative disease, cancer, and severe acute brain injury. We evaluated: (I) size and quantity of EVs by nanoparticle tracking analysis (NTA) and vesicle flow cytometry (VFC), (II) RNA yield and purity using four RNA isolation kits, (III) replication of RNA yields within and between laboratories, and (IV) composition of total and EV RNAs by reverse transcription–quantitative polymerase chain reaction (RT-qPCR) and RNA sequencing (RNASeq). The CSF contained ~106 EVs/μL by NTA and VFC. Brain tumour and SAH CSF contained more EVs and RNA relative to normal, AD, and PD. RT-qPCR and RNASeq identified disease-related populations of microRNAs and messenger RNAs (mRNAs) relative to normal CSF, in both total and EV fractions. This work presents relevant measures selected to inform the design of subsequent replicative CSF studies. The range of neurological diseases highlights variations in total and EV RNA content due to disease or collection site, revealing critical considerations guiding the selection of appropriate approaches and controls for CSF studies.

OBJECTIVE Aneurysmal subarachnoid hemorrhage (aSAH) may be complicated by hydrocephalus in 6.5%-67% of cases. Some patients with aSAH develop shunt dependency, which is often managed by ventriculoperitoneal shunt placement. The objectives of this study were to review published risk factors for shunt dependency in patients with aSAH, determine the level of evidence for each factor, and calculate the magnitude of each risk factor to better guide patient management. METHODS The authors searched PubMed and MEDLINE databases for Level A and Level B articles published through December 31, 2014, that describe factors affecting shunt dependency after aSAH and performed a systematic review and meta-analysis, stratifying the existing data according to level of evidence. RESULTS On the basis of the results of the meta-analysis, risk factors for shunt dependency included high Fisher grade (OR 7.74, 95% CI 4.47-13.41), acute hydrocephalus (OR 5.67, 95% CI 3.96-8.12), in-hospital complications (OR 4.91, 95% CI 2.79-8.64), presence of intraventricular blood (OR 3.93, 95% CI 2.80-5.52), high Hunt and Hess Scale score (OR 3.25, 95% CI 2.51-4.21), rehemorrhage (OR 2.21, 95% CI 1.24-3.95), posterior circulation location of the aneurysm (OR 1.85, 95% CI 1.35-2.53), and age ≥ 60 years (OR 1.81, 95% CI 1.50-2.19). The only risk factor included in the meta-analysis that did not reach statistical significance was female sex (OR 1.13, 95% CI 0.77-1.65). CONCLUSIONS The authors identified several risk factors for shunt dependency in aSAH patients that help predict which patients are likely to require a permanent shunt. Although some of these risk factors are not independent of each other, this information assists clinicians in identifying at-risk patients and managing their treatment.