Propyl-phthalimide Cyclotricatechylene-Based Chemosensor for Sulfosulfuron Detection: Hybrid Computational and Experimental Approach.

The detection of trace amounts of sulfosulfuron, a pesticide of increasing importance, has become a pressing issue, prompting the development of effective chemosensors. In this study, we functionalized cyclotricatechylene (CTC) with propyl-phthalimide due to the presence of electronegative oxygen and nitrogen binding sites. Our optimized ligand displayed the highest docking score with sulfosulfuron, and experimental studies confirmed a significant fluorescence enhancement upon its interaction with sulfosulfuron. To gain a deeper understanding of the binding mechanism, we introduced density functional theory (DFT) studies. We carried out binding constant, Job's plot, and limit of detection (LOD) calculations to establish the effectiveness of our chemosensor as a selective detector for sulfosulfuron. These findings demonstrate the potential of our chemosensor for future applications in the field of pesticide detection.

Development and Validation of a Multivariable Model to Predict Surgical Outcome in Patients with Chiari malformations.

Background: Surgical outcome predictive models for Chiari malformations (CM) which are applicable to all age groups and simple enough to use on outpatient basis are lacking. Objective: The aim of this study was to develop and validate a preoperative index for predicting long-term outcomes in Chiari 1 (CM1) and Chiari 0 (CM0) malformations. Materials and Methods: It was a single-institution, ambidirectional, cohort study from 2014 to 2019, having patients between 5 to 70 years. Outcome was assessed using Chicago Chiari outcome score (CCOS) over 2 years follow-up. Preoperative clinical and radiological factors were analyzed using Chi-square test and Mann Whitney U test, in relation to CCOS and those attaining P value ≤0.05, were used to develop model - Chiari Outcome Predictive Index (COPI). COPI was internally validated using 10-fold cross-validation and c-statistic for discrimination. Results: A total of 88 patients (66 in development and 22 in validation cohort) were included in the study. Outcome was negatively associated with presence of motor, sensory or cranial nerve symptoms, poor functional status, basilar invagination, and tonsillar descent. It was positively associated with shorter duration of presenting symptom (<9 months) and syrinx diameter <6 mm. COPI predicted CCOS with 91.1% accuracy (10-fold cross-validation). It had excellent discrimination for improved outcome (c = 0.968 in development and 0.976 in validation cohort), at threshold index of -1. Conclusions: COPI is simple tool that can be administered in outpatient setting. It can facilitate evidence-based preoperative counseling of patients, to help them develop reasonable expectations regarding surgical outcomes.

Efficient dye-sensitized solar cell fabricated using a less toxic alternative to electrolyte and charge collector.

The photovoltaic investigation of novel and efficient dye-sensitized solar cells is discussed in this paper. Ruthenium-based synthetic dye (N3) is used as a sensitizer. A less toxic alternative is suggested for toxic indium-based glass substrates by using aluminum-doped zinc oxide (AZO) and fluorine-doped tin oxide (FTO) as charge collectors. Moreover, the electrolyte used is a mixture of polymer (polyaniline) and an iodide-triiodide couple to go for the approach involving a lower amount of iodine. In the paper study, on the extent of light, absorption of dye is done by ultraviolet-visible (UV-vis) spectroscopy. The morphological study of sheets is done using scanning electron microscopic (SEM) images to understand the binding of titania on photoanode. Photovoltaic characteristics (I-V) and induced photon to current efficiency (IPCE) measurements, and light harvesting efficiency (LHE) are also investigated. The highest power conversion efficiency of 6.18% is observed in the suggested fabricated green solar cell. Hence, more efficient, indium-free, and novel cell is fabricated by the usage of different charge collector substrates and quasi solid-state electrolytes.

Immuno-phenotyping of IDH-mutant grade 3 astrocytoma and IDH-wildtype glioblastoma reveals specific differences in cells of myeloid origin.

Gliomas are heavily infiltrated with immune cells of myeloid origin. Past studies have shown that high-grade gliomas have a higher proportion of alternatively activated and suppressive myeloid cells when compared to low-grade gliomas, which correlate with poor prognosis. However, the differences in immune cell phenotypes within high-grade gliomas (between grade 3 and grade 4 or GBM) are relatively less explored, and a correlation of phenotypic characteristics between immune cells in the blood and high-grade tumors has not been performed. Additionally, myeloid cells of granulocytic origin present in gliomas remain poorly characterized. Herein, we address these questions through phenotypic characterizations of monocytes and neutrophils present in blood and tumors of individuals with glioblastoma (GBM, IDH-wild type) or grade 3 IDH-mutant gliomas. We observe that neutrophils are highly heterogeneous among individuals with glioma, and are different from healthy controls. We also show that CD163 expressing M2 monocytes are present in greater proportions in GBM tissue when compared to grade 3 IDH-mutant glioma tissue, and a larger proportion of granulocytic myeloid-derived suppressor cells are present in grade 3 IDH-mutant gliomas when compared to GBM. Finally, we demonstrate that the expression levels of CD86 and CD63 showed a high correlation between blood and tumor and suggest that these may be used as possible markers for prognosis.

Techniques and Nuances in Ventriculoperitoneal Shunt Surgery.

BACKGROUND: Ventriculoperitoneal shunt surgery (VPS) is a simple solution to the problem of hydrocephalus. However, it is associated with significant complications. Meticulous attention to a variety of factors, techniques, and nuances in VPS can reduce these complications. OBJECTIVE: To review the various techniques and nuances during the different stages of VPS. METHODS AND MATERIAL: PubMed search for original and review articles dealing with various techniques used during VPS. RESULTS: Thorough preoperative planning for VPS reduces operative time and complications. A standardized shunt surgery protocol significantly reduces shunt infection. Good and appropriate surgical technique can enhance the safety of the procedure. Anterior entry point is better than posterior entry point. Shunt tip should be away from choroid plexus, but the exact location is not vital for shunt survival. Proper placement of the shunt in the subgaleal and subcutaneous plane reduces wound and skin breakdown over the shunt. The trocar and laparoscopic methods to access the peritoneum are associated with fewer distal obstructions compared to mini-laparotomy. Perioperative antibiotic prophylaxis, use of antibiotic-impregnated shunts, and sutures are proven techniques to reduce shunt infection. CONCLUSIONS: Preoperative planning, a standardized shunt surgery protocol, good surgical technique, gentle tissue handling, and short surgery duration are essential to reduce VPS complications. Specifically, use of anterior entry point, correct tunneling of the shunt in the subgaleal and subcutaneous plane, appropriate antibiotic prophylaxis, use of antibiotic-impregnated shunts, and meticulous skin closure using antimicrobial sutures can lead to a reduction in shunt malfunction and infection.

Indian Society of Pediatric Neurosurgery Consensus Guidelines on Preventing and Managing Shunt Infection: Version 2020-21.

BACKGROUND: Shunt infection is the most significant morbidity associated with shunt surgery. Based on the existing literature for the prevention and management of shunt infection, region and resource-specific recommendations are needed. METHODS: In February 2020, a Guidelines Development Group (GDG) was created by the Indian Society of Paediatric Neurosurgery (IndSPN) to formulate guidelines on shunt infections, which would be relevant to our country and LMIC in general. An initial email survey identified existing practices among the membership of the IndSPN, and eight broad issues pertaining to shunt infection were identified. Next, members of the GDG performed a systematic review of the literature on the prevention and management of shunt infection. Then, through a series of virtual meetings of the GDG over 1 year, evidence from the literature was presented to all the members and consensus was built on different aspects of shunt infection. Finally, the guidelines document was drafted and circulated among the GDG for final approval. Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to grade the evidence and strength of recommendation. RESULTS: The guidelines are divided into eight sections. Level I and Level II evidence was available for only five recommendations and led to a moderate level of recommendations. Most of the available evidence was at Level III and below, and hence the level of recommendation was low or very low. A consensus method was used to provide recommendations for several issues. CONCLUSIONS: Although most of the recommendations for the prevention and management of shunt infections are based on a low level of evidence, we believe that this document will provide a useful reference to neurosurgeons not only in India but also in other low and middle income countries. These guidelines need to be updated as and when new evidence emerges.

Cerebellar mutism after posterior fossa tumor resection in children: a multicenter international retrospective study to determine possible modifiable factors.

PURPOSE: A preliminary survey of pediatric neurosurgeons working at different centers around the world suggested differences in clinical practice resulting in variation in the risk of pediatric cerebellar mutism (CM) and cerebellar mutism syndrome (CMS) after posterior fossa (PF) tumor resection. The purposes of this study were (1) to determine the incidence and severity of CM and CMS after midline PF tumor resection in children treated at these centers and (2) to identify potentially modifiable factors related to surgical management (rather than tumor biology) that correlate with the incidence of CM/CMS. METHODS: Attending pediatric neurosurgeons at British Columbia's Children's Hospital (BCCH) and neurosurgeons who completed a pediatric neurosurgery fellowship at BCCH were invited to provide data from the center where they currently practiced. Children aged from birth to less than 18 years who underwent initial midline PF tumor resection within a contemporary, center-selected 2-year period were included. Data was obtained by retrospective chart and imaging review. Modifiable surgical factors that were assessed included pre-resection surgical hydrocephalus treatment, surgical positioning, ultrasonic aspirator use, intraoperative external ventricular drain (EVD) use, surgical access route to the tumor, and extent of resection. CM was defined as decreased or absent speech output postoperatively and CMS as CM plus new or worsened irritability. RESULTS: There were 263 patients from 11 centers in 6 countries (Canada, Germany, the Netherlands, India, Indonesia, and the USA). Median age at surgery was 6 years (range < 1 to 17 years). The overall incidence of postoperative CM was 23.5% (range 14.7-47.6% for centers with data on ≥ 20 patients). The overall incidence of CMS was 6.5% (range 0-10.3% for centers contributing data on ≥ 20 patients). A multivariate logistic regression on the full data set showed no significant association between pre-resection surgical hydrocephalus treatment, prone position, ultrasonic aspirator use, EVD use, telovelar approach, complete or near total resection, or treating center and either postoperative CM or CMS. CONCLUSIONS: While there was variation in surgical management of midline PF tumors among centers participating in this study, the factors in management that were examined did not predict postoperative CM or CMS.

Moyamoya syndrome as a manifestation of varicella-associated cerebral vasculopathy-case report and review of literature.

BACKGROUND: Varicella-associated cerebral vasculopathy (VACV) is a serious complication of Varicella zoster virus (VZV) infection. VACV has protean manifestations, with varying clinical, radiological features and prognosis. CASE DESCRIPTION: Moyamoya syndrome (MMS) with VACV is reported in few cases in the past. All the patients were in paediatric age group, presenting with multiple episodes of transient ischemic attacks (TIAs) and infarct. Our case was a 10-year-old Indian girl with ischemic stroke due to VACV who was treated with intravenous acyclovir. She presented 11 months later with multiple episodes of TIAs. Her angiogram showed bilateral moyamoya vasculature. Acetazolamide challenge study revealed areas of hypoperfusion. Previously reported such cases had been treated medically with steroids and antiplatelets. Most of these patients had resolution of motor symptoms after long follow-up; however, this period was marred by recurrent symptoms. Our patient underwent cerebral revascularisation procedure, following which her TIAs resolved, there was improvement in her limb power and, according to her parents, her performance in school has improved at 2-year follow-up. CONCLUSION: MMS can be a manifestation of VACV and should be suspected in paediatric patient of non-east Asian population. These patients require treatment with intravenous acyclovir to inactivate the virus. Those with TIAs should undergo cerebral revascularisation procedures. Medical management should be reserved for patients with adequate collaterals.

Identification of a Novel Splice Variant of Neural Cell Adhesion Molecule in Glioblastoma Through Proteogenomics Analysis.

Splice variants are known to be important in the pathophysiology of tumors, including the brain cancers. We applied a proteogenomics pipeline to identify splice variants in glioblastoma (GBM, grade IV glioma), a highly malignant brain tumor, using in-house generated mass spectrometric proteomic data and public domain RNASeq dataset. Our analysis led to the identification of a novel exon that maps to the long isoform of Neural cell adhesion molecule 1 (NCAM1), expressed on the surface of glial cells and neurons, important for cell adhesion and cell signaling. The presence of the novel exon is supported with the identification of five peptides spanning it. Additional peptides were also detected in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel separated proteins from GBM patient tissue, underscoring the presence of the novel peptides in the intact brain protein. The novel exon was detected in the RNASeq dataset in 18 of 25 GBM samples and separately validated in additional 10 GBM tumor tissues using quantitative real-time-polymerase chain reaction (qRT-PCR). Both transcriptomic and proteomic data indicate downregulation of NCAM1, including the novel variant, in GBM. Domain analysis of the novel NCAM1 sequence indicates that the insertion of the novel exon contributes extra low-complexity region in the protein that may be important for protein-protein interactions and hence for cell signaling associated with tumor development. Taken together, the novel NCAM1 variant reported in this study exemplifies the importance of future multiomics research and systems biology applications in GBM.

Endothelial nitric oxide synthase mediates the cerebrovascular effects of erythropoietin in traumatic brain injury.

BACKGROUND: Erythropoietin (Epo) improves post-traumatic cerebral blood flow (CBF), pressure autoregulation, and vascular reactivity to l-arginine. This study examines the dependence of these cerebral hemodynamic effects of Epo on nitric oxide generated by endothelial nitric oxide synthase (eNOS). METHODS: Using laser Doppler flow imaging, CBF was monitored in wild-type (WT) and eNOS-deficient mice undergoing controlled cortical impact followed by administration of Epo (5000 U/kg) or normal saline. RESULTS: Cerebral blood flow decreased in all groups post-injury with the greatest reductions occurring at the impact site. Epo administration resulted in significantly higher CBF in the peri-contusional sites in the WT mice [70.2 ± 3.35% in Epo-treated compared to 53 ± 3.3% of baseline in saline-treated mice (p < 0.0001)], but no effect was seen in the eNOS-deficient mice. No CBF differences were found at the core impact site where CBF dropped to 20-25% of baseline in all groups. CONCLUSION: These differences between eNOS-deficient and WT mice indicate that the Epo mediated improvement in CBF in traumatic brain injury is eNOS dependent.

Reduced contribution of executive functions in impaired working memory performance in mild traumatic brain injury patients.

AIM: Mild traumatic brain injury (MTBI) is associated with often selective impairment of both working memory (WM) and the executive functions (EFs). Research indicates that one of the commonest deficits present in MTBI patients falls in the domain of WM. We aimed to investigate the role of EFs in WM impairment following MTBI. METHODS: Performance on the tests of EFs and the verbal and visuo-spatial WM of 30 consecutive MTBI patients were compared with age/education/IQ matched 30 normal healthy control participants. Correlation between EFs and WM was studied separately for the MTBI and the control group. RESULTS: The MTBI and control group were tested on a range of EF tests and WM. The MTBI group was demonstrated impairment on verbal and visuo-spatial WM and category fluency tests only. Furthermore, the MTBI group had fewer significant correlations between the WM and EFs (5 out of 54 possible correlations) than in the control group (13 out of 54 possible correlations). CONCLUSIONS: We suggest that MTBI may lead to WM deficits as the contribution of executive processes to support the WM is diminished following MTBI. Such an understanding of the poor WM performance in MTBI patients will be helpful when planning appropriate strategies for cognitive rehabilitation.

Usefulness of stereotactic biopsy and neuroimaging in management of HIV-1 Clade C associated focal brain lesions with special focus on cerebral toxoplasmosis.

BACKGROUND: Focal brain lesions (FBL) in HIV/AIDS frequently pose a diagnostic dilemma as the etiology varies from infective (tuberculoma, toxoplasmosis and tuberculous abscesses) to neoplastic lesions like lymphoma. For determining etiology, advanced neuroimaging techniques, serological and molecular biological tests have been evolved with varying sensitivities/specificities. Stereotactic biopsy (STB) of the lesions is reserved for lesions unresponsive to appropriate therapy. OBJECTIVE AND METHODS: In this study, the diagnostic yield of neuroimaging [cranial CT (n=25), MRI (n=24), and Th201/99Tc SPECT scan (n=18)] is compared with histopathological diagnosis obtained by STB (n=21) or autopsy (n=4) in 25 HIV-1 subtype C seropositive individuals with FBL identified by neuroimaging with special reference to cerebral toxoplasmosis in an eighteen month study period (2006-2007). RESULTS AND CONCLUSION: Cerebral toxoplasmosis was the most frequent cause of FBL (21/25, 84%), followed by one case each of tuberculoma, progressive multifocal leukoencephalopathy (PML), primary central nervous system lymphoma (PCNSL) and measles inclusion body encephalitis (MIBE), the last two diagnosed at autopsy. Of the 21 cases of cerebral toxoplasmosis, definitive diagnosis with histopathological confirmation was available in 14/21 (66.6%), with indirect evidence suggesting probable toxoplasmosis in seven, all of whom responded to antitoxoplasma therapy. CT and MRI had comparable specificities (75%), while MRI had marginally higher sensitivity (85% versus 80.9%) in detecting multiple lesions. The positive predictive value of both CT and MRI was identical (94.4%), suggesting that CT maybe a cost effective screening tool in resource restricted settings, for evaluating FBL. Sensitivity of 99Tc SPECT scan for diagnosing inflammatory lesions was 75% but failed to differentiate PCNSL from toxoplasmosis. This study is the first of its kind from India analyzing FBL with specific focus on cerebral toxoplasmosis in the setting of HIV-1 subtype C.

Infant brain tumors: a neuropathologic population-based institutional reappraisal.

The factors that impact the long-term functional outcome for infants with brain tumor are unclear. The clinicopathologic features of all infant brain tumors occurring at our institution (1982-2005) were reexamined to explore the factors influencing prognosis. The details of the neuropathologic review are reported herein. Thirty-five cases were identified and included 7 astrocytomas (6 low grade and 1 glioblastoma), 6 atypical teratoid rhabdoid tumors, 5 choroid plexus papillomas, 4 ependymomas (3 anaplastic), 4 teratomas (3 immature), 2 supratentorial primitive neuroectodermal tumors, 2 gangliogliomas, 2 desmoplastic tumors of infancy, and 1 each of "medulloblastoma with extensive nodularity," adamantinomatous craniopharyngioma, and 1 "malignancy not otherwise specified." The original diagnosis was changed in 8 cases (23%), and atypical teratoid rhabdoid tumors was the most common revision (n = 5). Case 9 was unusual in that both the patient and her 2-year-old sister displayed INI-1 immunonegative posterior fossa tumors and extended survival. Tumor grade was altered in 6 cases (17%), the most significant instance being the downgrading from the World Health Organization grade IV to I (case 18: supratentorial primitive neuroectodermal tumors to desmoplastic tumors of infancy). As opposed to other reports in the literature, our cohort contained a substantially higher frequency of atypical teratoid rhabdoid tumors and a lower frequency of medulloblastoma. Changes in the histologic diagnosis/grade in a significant subset of cases most likely reflect the continual evolution of brain tumor classification schemes. INI-1 immunohistochemistry was instrumental in the pathologic assessment of select cases and raised the possibility that atypical teratoid rhabdoid tumors may be the most common infant brain malignancy.

Intracranial tumors in infants: long-term functional outcome, survival, and its predictors.

OBJECTIVE: Intracranial tumors are rare in the first year of life. This study evaluates survival rates and functional outcomes of survivors at least 5 years after diagnosis and the predictors of this outcome. METHODS: A retrospective chart review of all infants with a primary intracranial tumor was carried out. Radiology and pathology were re-reviewed. Outcome was assessed at 5 years or more after diagnosis using Bloom's categories (Bloom 1-2 = good outcome, the rest = poor outcome) and late effects severity scoring. Age, tumor location, size, extent of tumor resection, type of adjuvant therapy given, and WHO grade of tumor histology were evaluated as predictors of outcome. RESULTS: Among 35 infants, 20 (57%) survived, with 12 (34%) having a good outcome. Deficits among the survivors included neurological dysfunction in 14 (70%), visual impairment in 9 (45%), endocrine dysfunction in 5 (25%), and auditory disability in 3 (15%). Ten of the 20 survivors were either attending regular school or were engaged in a skilled job. At presentation, older age and an infratentorial location of the tumor are predictors of poor outcome. After histopathological diagnosis, the WHO grading of tumor is the only independent predictor of survival (p = 0.002) and functional outcome (p < 0.001). CONCLUSION: About a third of the infants diagnosed with brain tumors (34%) had a good functional outcome and approximately a quarter of them (28%) were able to attend regular school or take up a skilled job. After tissue diagnosis, histological grade of tumor is the only independent predictor associated with outcome.

Position of probe determines prognostic information of brain tissue PO2 in severe traumatic brain injury.

BACKGROUND: Monitoring brain tissue PO2 (PbtO2) is part of multimodality monitoring of patients with traumatic brain injury (TBI). However, PbtO2 measurement is a sampling of only a small area of tissue surrounding the sensor tip. OBJECTIVE: To examine the effect of catheter location on the relationship between PbtO2 and neurological outcome. METHODS: A total of 405 patients who had PbtO2 monitoring as part of standard management of severe traumatic brain injury were studied. The relationships between probe location and resulting PbtO2 and outcome were examined. RESULTS: When the probe was located in normal brain, PbtO2 averaged 30.8 ± 18.2 compared with 25.6 ± 14.8 mm Hg when placed in abnormal brain (P < .001). Factors related to neurological outcome in the best-fit logistic regression model were age, PbtO2 probe position, postresuscitation motor Glasgow Coma Scale score, and PbtO2 trend pattern. Although average PbtO2 was significantly related to outcome in univariate analyses, it was not significant in the final logistic model. However, the interaction between PbtO2 and probe position was statistically significant. When the PbtO2 probe was placed in abnormal brain, the average PbtO2 was higher in those with a favorable outcome, 28.8 ± 12.0 mm Hg, compared with those with an unfavorable outcome, 19.5 ± 13.7 mm Hg (P = .01). PbtO2 and outcome were not related when the probe was placed in normal-appearing brain. CONCLUSION: These results suggest that the location of the PbtO2 probe determines the PbtO2 values and the relationship of PbtO2 to neurological outcome.

Histopathological and behavioral effects of immediate and delayed hemorrhagic shock after mild traumatic brain injury in rats.

The purpose of this study was to investigate the increased susceptibility of the brain, after a controlled mild cortical impact injury, to a secondary ischemic insult. The effects of the duration and the timing of the secondary insult after the initial cortical injury were studied. Rats anesthetized with isoflurane underwent a 3 m/sec, 2.5-mm deformation cortical impact injury followed by hypotension to 40 mm Hg induced by withdrawing blood from a femoral vein. The duration of hypotension was varied from 40 to 60 min. The timing of 60 min of hypotension was varied from immediately post-injury to 7 days after the injury. Outcome was assessed by behavioral tasks and histological examination at 2 weeks post-injury. A separate group of animals underwent measurement of the acute physiology including mean blood pressure (MAP), intracranial pressure (ICP), and cerebral blood flow (CBF) using a laser Doppler technique. Increasing durations of hypotension resulted in marked expansion of the contusion, from 6.5±1.8 mm³ with sham hypotension to 27.1±3.9 mm³ with 60 min of hypotension. This worsening of the contusion was found only when then hypotension occurred immediately after injury or at 1 h after injury. CA3 neuron loss followed a similar pattern, but the injury group differences were not significant. Motor tasks, including beam balance and beam walking, were significantly worse following 50 and 60 min of hypotension. Performance on the Morris water maze task was also significantly related to the injury group. Studies of the acute cerebral hemodynamics demonstrated that CBF was significantly more impaired during hypotension in the animals that underwent the mild TBI compared to those that underwent sham TBI. The perfusion deficit was worst at the impact site, but also significant in the pericontusional brain. With 50 and 60 min of hypotension, CBF did not recover following resuscitation at the impact site, and recovered only transiently in the pericontusional brain. These results demonstrate that mild TBI, like more severe levels of TBI, can impair the brain's ability to maintain CBF during a period of hypotension, and result in a worse outcome.

Diffusion-weighted imaging and pathological correlation in pediatric medulloblastomas-"They are not always restricted!".

INTRODUCTION: Some investigators have suggested that medulloblastomas can be distinguished from other cerebellar neoplasms by demonstrating "restricted diffusion" on the Apparent Diffusion Coefficient (ADC) map obtained from diffusion-weighted imaging (DWI) sequences on magnetic resonance imaging. Previous authors have postulated that this observed restricted diffusion is a reflection of very high cell density. There has been a tendency to assert that pediatric medulloblastoma uniformly demonstrates restricted diffusion on DWI. However, our clinical observation has been that there are pediatric medulloblastomas that exhibit normal or even increased diffusion on DWI. The current study was undertaken primarily to determine whether restricted diffusion is uniformly present in pediatric medulloblastoma and secondly to look for pathological features that might distinguish medulloblastomas with and without restricted diffusion. METHODS: The DWI characteristics of pathologically confirmed medulloblastomas diagnosed at our institution were retrospectively reviewed. The ADC was obtained in two non-overlapping, solid, non-hemorrhagic, non-necrotic regions of tumor and averaged. An ADC below 1 × 10(-3) mm(2)/s was considered to represent restricted diffusion. A detailed pathologic review of each tumor was conducted. RESULTS: Ten cases of medulloblastoma were reviewed, of which two demonstrated average ADCs above 1 × 10(-3) mm(2)/s (1.223 and 1.169 × 10(-3) mm(2)/s, respectively), indicating no restricted diffusion. Pathologic review revealed that both of these non-restricting cases displayed a lack of reticulin deposition by light microscopy. CONCLUSION: DWI does not appear to be an entirely reliable means of distinguishing medulloblastomas from other cerebellar neoplasms. Histologically, restricted diffusion in medulloblastomas may be related to reticulin deposition.

Post-concussion syndrome: Correlation of neuropsychological deficits, structural lesions on magnetic resonance imaging and symptoms.

BACKGROUND: Post-concussion syndrome (PCS) associated with mild traumatic brain injury (MTBI) can cause long-lasting disabilities. Magnetic resonance imaging (MRI) evaluation in these patients may demonstrate structural lesions that correlate with functional deficits on neuropsychological testing. However, little is known about the significance of the relationship between structural lesions on MRI, functional deficits on neuropsychological evaluation and outcome in patients with MTBI. AIMS: To assess neuropsychological deficits and structural lesions on MRI in patients with PCS following MTBI, and to find correlation between these findings and PCS. SETTINGS AND DESIGN: Prospective, observational, cohort study in a tertiary hospital. MATERIALS AND METHODS: The study cohort included consecutive patients with MTBI (three months or more duration) and PCS. All the patients in the cohort had neuropsychological testing using the National Institute of Mental Health and Neurological Sciences Neuropsychological Battery for head injury and also MRI using T1, T2 and FLAIR sequences. Statistical analysis was done using Fisher's Exact test of significance. RESULTS: All the 20 patients evaluated had neuropsychological deficits. Eleven patients had lesions on MRI. Disturbances of sleep, behavior and memory and abnormalities in tests for mental speed were more frequent in patients with lesions on MRI, but were not statically significant (P = 0.08). Both the test modalities localized lesions predominantly to the frontal and temporal lobes. All the symptoms observed in the patients were associated with prefrontal dysfunction on neuropsychological testing. CONCLUSIONS: Prefrontal dysfunction is invariably associated with PCS following MTBI. Structural lesions on MRI may not always be present but when present may influence the degree or severity of the symptoms.