Computational Identification of Tumor Anatomic Location Associated with Survival in 2 Large Cohorts of Human Primary Glioblastomas.

BACKGROUND AND PURPOSE: Tumor location has been shown to be a significant prognostic factor in patients with glioblastoma. The purpose of this study was to characterize glioblastoma lesions by identifying MR imaging voxel-based tumor location features that are associated with tumor molecular profiles, patient characteristics, and clinical outcomes. MATERIALS AND METHODS: Preoperative T1 anatomic MR images of 384 patients with glioblastomas were obtained from 2 independent cohorts (n = 253 from the Stanford University Medical Center for training and n = 131 from The Cancer Genome Atlas for validation). An automated computational image-analysis pipeline was developed to determine the anatomic locations of tumor in each patient. Voxel-based differences in tumor location between good (overall survival of >17 months) and poor (overall survival of <11 months) survival groups identified in the training cohort were used to classify patients in The Cancer Genome Atlas cohort into 2 brain-location groups, for which clinical features, messenger RNA expression, and copy number changes were compared to elucidate the biologic basis of tumors located in different brain regions. RESULTS: Tumors in the right occipitotemporal periventricular white matter were significantly associated with poor survival in both training and test cohorts (both, log-rank P < .05) and had larger tumor volume compared with tumors in other locations. Tumors in the right periatrial location were associated with hypoxia pathway enrichment and PDGFRA amplification, making them potential targets for subgroup-specific therapies. CONCLUSIONS: Voxel-based location in glioblastoma is associated with patient outcome and may have a potential role for guiding personalized treatment.

Arterial spin-labeled perfusion of pediatric brain tumors.

BACKGROUND AND PURPOSE: Pediatric brain tumors have diverse pathologic features, which poses diagnostic challenges. Although perfusion evaluation of adult tumors is well established, hemodynamic properties are not well characterized in children. Our goal was to apply arterial spin-labeling perfusion for various pathologic types of pediatric brain tumors and evaluate the role of arterial spin-labeling in the prediction of tumor grade. MATERIALS AND METHODS: Arterial spin-labeling perfusion of 54 children (mean age, 7.5 years; 33 boys and 21 girls) with treatment-naive brain tumors was retrospectively evaluated. The 3D pseudocontinuous spin-echo arterial spin-labeling technique was acquired at 3T MR imaging. Maximal relative tumor blood flow was obtained by use of the ROI method and was compared with tumor histologic features and grade. RESULTS: Tumors consisted of astrocytic (20), embryonal (11), ependymal (3), mixed neuronal-glial (8), choroid plexus (5), craniopharyngioma (4), and other pathologic types (3). The maximal relative tumor blood flow of high-grade tumors (grades III and IV) was significantly higher than that of low-grade tumors (grades I and II) (P < .001). There was a wider relative tumor blood flow range among high-grade tumors (2.14 ± 1.78) compared with low-grade tumors (0.60 ± 0.29) (P < .001). Across the cohort, relative tumor blood flow did not distinguish individual histology; however, among posterior fossa tumors, relative tumor blood flow was significantly higher for medulloblastoma compared with pilocytic astrocytoma (P = .014). CONCLUSIONS: Characteristic arterial spin-labeling perfusion patterns were seen among diverse pathologic types of brain tumors in children. Arterial spin-labeling perfusion can be used to distinguish high-grade and low-grade tumors.

Normal sagittal and coronal suture widths by using CT imaging.

BACKGROUND AND PURPOSE: Pediatric cranial sutures are often evaluated for abnormal diastasis upon presentation to the emergency department after trauma or during a neurologic consultation; however, few normative data for CT measurements exist. This study establishes normal means for the sagittal and coronal suture widths during the first year of life by using CT. MATERIALS AND METHODS: The sagittal suture and bilateral coronal sutures were evaluated for 483 patients, ages 1 day to 395 days collected retrospectively from electronic medical records. Histograms as well as normality and boxplots were used to view the distribution of the data. An analysis of variance was performed for each suture measured by using month of age as the independent class variable. RESULTS: The average proximal suture widths for the sagittal and coronal sutures at zero months of age were 5.0 ± 0.2 and 2.5 ± 0.1 mm, respectively. From zero to 1 month of age, these sutures narrowed significantly to 2.4 ± 0.1 and 1.3 ± 0.1 mm, respectively. From 1 to 12 months of age, sutures narrowed gradually. The proximal coronal suture widths showed a significant reduction from 1 month to 12 months (1.3 ± 0.1-0.8 ± 0.1 mm). CONCLUSIONS: The normative values for suture widths established by CT scan among this large population may be used to assess the infant calvaria for suture diastasis.

The TUNEL assay consistently underestimates DNA damage in human spermatozoa and is influenced by DNA compaction and cell vitality: development of an improved methodology.

The purpose of this study was to evaluate the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay as a method for assessing DNA damage in human spermatozoa. The conventional assay was shown to be insensitive and unresponsive to the DNA fragmentation induced in human and mouse spermatozoa on exposure to Fenton reagents (H2O2 and Fe(2+) ). However, both time- and dose-dependent responses could be readily detected if the chromatin was exposed to 2 mm dithiothreitol (DTT) for 45 min prior to fixation. This modified version of the assay significantly enhanced the TUNEL signals generated by subpopulations of spermatozoa isolated on discontinuous Percoll gradients as well as the responses triggered by reagents (arachidonic acid and menadione) that are known to stimulate superoxide anion production by human spermatozoa. DTT exposure also improved the signals detected with chromomycin A3 (CMA3), a probe designed to determine the efficacy of chromatin protamination, and enhanced the correlation observed between this criterion of sperm quality and the TUNEL assay. Finally, the output of the TUNEL assay was found to be highly correlated with sperm vitality. The TUNEL methodology was therefore further refined to incorporate a vital stain that covalently bound to intracellular amine groups in non-viable cells. This tag remained associated with the spermatozoa during fixation and processing for the TUNEL assay so that ultimately, both DNA integrity and vitality could be simultaneously assessed in the same flow cytometry assay. The methods described in this article are simple and robust and should facilitate research into the causes of DNA damage in human spermatozoa.

Mechanisms for how inhaled multiwalled carbon nanotubes suppress systemic immune function in mice.

The potential health effects of inhaling carbon nanotubes are important because of possible exposures in occupational settings. Previously, we have shown mice that have inhaled multiwalled carbon nanotubes have suppressed systemic immune function. Here, we show the mechanisms for this immune suppression. Mice were exposed to 0, 0.3 or 1 mg m(-3) multiwalled carbon nanotubes for 6 h per day for 14 consecutive days in whole-body inhalation chambers. Only those exposed to a dose of 1 mg m(-3) presented suppressed immune function; this involved activation of cyclooxygenase enzymes in the spleen in response to a signal from the lungs. Spleen cells from exposed animals partially recovered their immune function when treated with ibuprofen, a drug that blocks the formation of cyclooxygenase enzymes. Knockout mice without cyclooxygenase enzymes were not affected when exposed to multiwalled carbon nanotubes, further confirming the importance of this enzyme in suppression. Proteins from the lungs of exposed mice suppressed the immune function of spleen cells from normal mice, but not those from knockout mice. Our findings suggest that signals from the lung can activate signals in the spleen to suppress the immune function of exposed mice.

Cystic meningioangiomatosis in neurofibromatosis type 2: an MRI-pathological study.

We report cerebral cystic meningioangiomatosis in a patient with neurofibromatosis type 2. An 18-year-old woman presented with progressive hemiparesis secondary to a meningioma at the foramen magnum. Her MR examination also demonstrated three small cortical and subcortical cystic lesions. She underwent surgery for the meningioma, but died from brainstem infarction. Post-mortem histopathological examination of the cystic lesions showed enlarged subcortical perivascular spaces with overlying meningioangiomatosis. The unusual features and possible pathogenesis are discussed.

Analysis of chaperone proteins associated with human spermatozoa during capacitation.

Mammalian spermatozoa must undergo a post-ejaculatory period of maturation, known as capacitation, before they can engage in the process of fertilization. Studies in the mouse have established that capacitation facilitates sperm-zona recognition via mechanisms that involve the appearance of tyrosine phosphorylated chaperone proteins on the sperm surface overlying the acrosome, the site of sperm-zona recognition. In this study, we examined whether a similar relationship existed between the tyrosine phosphorylation events associated with capacitation and sperm-zona interaction in human spermatozoa. These studies confirmed that capacitation is associated with an increase in both sperm-zona binding and an increase in tyrosine phosphorylation over the sperm tail. However, we could not detect the surface expression of phosphotyrosine residues over the sperm head, as observed with murine spermatozoa. Moreover, although we could clearly detect a number of chaperone proteins in human spermatozoa including HSPE1, DNAJB1, HSPD1, HSPA1A, HSPCA, HSPH1, HSPA5 and TRA1, none of these molecules were expressed on the sperm surface. On the basis of these results, it is unlikely that these proteins play an active role in the remodeling of the sperm surface during capacitation. We conclude that strong species-specific differences exist in the molecular mechanisms that drive sperm-egg recognition and that alternative, chaperone-independent, mechanisms must underpin sperm-zona interaction in the human.

New-onset temporal lobe epilepsy in children: lesion on MRI predicts poor seizure outcome.

OBJECTIVE: To determine factors predictive of long-term seizure outcome in children with new-onset temporal lobe epilepsy (TLE). METHODS: A community-based cohort of 77 children with new-onset TLE, including 14 with possible TLE, were followed prospectively with formal review 7 and 14 years following seizure onset. Diagnoses were re-evaluated at each review, and changed when new clinical, EEG, or imaging data were compelling. RESULTS: Sixty-four patients sustained the diagnosis of TLE over time; two were lost to follow-up. Age at follow-up was 12 to 29 years (median 20 years). Median follow-up was 13.7 years, 95% being followed for greater than 10 years. Nineteen patients were seizure free (SF) and off treatment, having not had seizures for 5 to 15 years. Duration of active TLE in the SF group was 1 to 8 years, the children being treated with 0 to 3 antiepileptic drugs (AEDs). Forty-three patients were not seizure free (NSF) and had ongoing seizures or had undergone epilepsy surgery. These children were treated with 1 to 10 AEDs. Fifteen NSF patients experienced 22 nonterminal seizure remissions of 1 to 7 years duration. Seventeen children had a significant antecedent to TLE. Lesions were identified on neuroimaging in 28 and included hippocampal sclerosis (HS) in 10, tumor in 8, and dysplasia in 7. All children with lesions on MRI were NSF (p < 0.001). Focal slowing on EEG was also associated with persistent seizures (p = 0.05), although this was correlated with a lesion on MRI. Infantile onset of epilepsy, family history of seizures, initial seizure frequency, antecedents, and early seizure remissions were not predictive of seizure outcome. CONCLUSION: Seizures spontaneously remit in approximately one third of children with new-onset TLE. A lesion on MRI predicts intractable seizures in TLE and the potential need for epilepsy surgery.

Identification of the sex-determining locus of Atlantic salmon (Salmo salar) on chromosome 2.

We have integrated data from linkage mapping, physical mapping and karyotyping to gain a better understanding of the sex-determining locus, SEX, in Atlantic salmon (Salmo salar). SEX has been mapped to Atlantic salmon linkage group 1 (ASL1) and is associated with several microsatellite markers. We have used probes designed from the flanking regions of these sex-linked microsatellite markers to screen a bacterial artificial chromosome (BAC) library, representing an 11.7x coverage of the Atlantic salmon genome, which has been HindIII fingerprinted and assembled into contigs. BACs containing sex-linked microsatellites and their related contigs have been identified and representative BACs have been placed on the Atlantic salmon chromosomes by fluorescent in situ hybridization (FISH). This identified chromosome 2, a large metacentric, as the sex chromosome. By positioning several BACs on this chromosome by FISH, it was possible to orient ASL1 with respect to chromosome 2. The region containing SEX appears to lie on the long arm between marker Ssa202DU and a region of heterochromatin identified by DAPI staining. BAC end-sequencing of clones within sex-linked contigs revealed five hitherto unmapped genes along the sex chromosome. We are using an in silico approach coupled with physical probing of the BAC library to extend the BAC contigs to provide a physical map of ASL1, with a view to sequencing chromosome 2 and, in the process, identifying the sex-determining gene.

Structural abnormalities remote from the seizure focus: a study using T2 relaxometry at 3 T.

OBJECTIVE: To determine the extent and severity of mesial temporal and subcortical signal abnormalities in patients with partial epilepsy. METHODS: T2 relaxation time maps were acquired in 50 consecutive patients and 55 control subjects on a 3 T MRI scanner. Twenty-two patients had hippocampal sclerosis (HS), 16 had malformations of cortical development (MCD), and 12 had no obvious MR abnormalities (normal MR). The following eight regions were measured bilaterally: hippocampus, anterior temporal lobe (ATL) white matter, amygdala, frontal lobe white matter, caudate, putamen, pallidum, and thalamus. RESULTS: In patients with HS, increased T2 relaxation times were found in the ipsilateral hippocampus and ATL but not in subcortical nuclei. In patients with MCD, increased T2 relaxation times were found in the temporal lobe (hippocampus, ATL) and in subcortical areas (caudate, putamen, and pallidum); in patients with normal MR, increased T2 relaxation times were found in the hippocampus and putamen. The degree of abnormality did not correlate with the duration of epilepsy or the estimated seizure load. CONCLUSIONS: Mesial temporal structures show increased T2 relaxation times not only in patients with hippocampal sclerosis but also in patients with a seizure focus remote from the hippocampus. Patients with normal MR and focal malformations of cortical development have increased T2 relaxation times in subcortical structures. Therefore, abnormalities in T2 relaxation time can be found remote from the seizure focus. They cannot be simply attributed to secondary seizure effects.

Hypertensive encephalopathy: antecedent to hippocampal sclerosis and temporal lobe epilepsy?

The authors describe three patients with refractory temporal lobe epilepsy (TLE) following an episode of hypertensive encephalopathy as their only identified antecedent event. All patients had typical MR features of hippocampal sclerosis (HS), and the two operated cases had typical HS histology and became seizure-free postoperatively. These cases suggest that hypertensive encephalopathy may be a rare form of initial precipitating injury, leading to TLE and HS.

Linoleic acid prevents chloride influx and cellular lysis in rabbit renal proximal tubules exposed to mitochondrial toxicants.

Despite many studies elucidating the mechanisms of necrotic cell death, the role of fatty acids released during necrosis remains to be determined. The goals of this study were to determine whether linoleic acid could protect rabbit renal proximal tubules (RPT) from necrotic cell death associated with mitochondrial dysfunction and oxidative injury and to determine the mechanisms involved. Exposure to antimycin A (10 microM) for 1 h or hypoxia (perfusion with 95% N(2)/5% CO(2)) for 1 or 2 h induced approximately 70% cellular lysis, as measured by lactate dehyrogenase release, versus 10% in controls. Preincubation with linoleic acid (100 microM) fully protected RPT from cellular lysis. RPT were also protected from lysis if linoleic acid was added 15 min after the addition of antimycin A. Measurements of free intracellular Ca(2+) concentrations showed that linoleic acid did not prevent the rise in intracellular Ca(2+) associated with a 30-min exposure to antimycin A. However, the influx of extracellular (36)Cl(-) following a 30-min exposure to antimycin A was ameliorated in the presence of linoleic acid. Linoleic acid did not prevent cellular lysis after exposure to hypoxia/reoxygenation (1 h/1 h) or t-butyl hydroperoxide (500 microM, 3 h). These data suggest that linoleic acid protects RPT during the late phase of cell death associated with inhibition of the electron transport chain but not oxidative injury. Several other fatty acids also protected RPT from lysis, and structure-activity relationship studies suggest that a free carboxyl terminus and at least one double bond are required for this action.

Near-total absence of the cerebellum.

We report five cases of near-total absence of the cerebellum with accompanying pontine hypoplasia. The cerebellar remnant in each case comprised only antero-superior masses, the posterior fossa being otherwise fluid filled. Three of these patients, two teenagers and an infant, presented a fairly consistent clinical and neuroradiological phenotype, and a few similar cases are recorded in the literature. The cerebellar remnant was irregular and asymmetrical, and no ventral pontine prominence was discernible. In at least the older two, cerebellar motor functions were not greatly compromised, and intellectual handicap was of a mild degree. We propose that these cases represent a distinct entity of "near-total absence of the cerebellum with flat ventral pons, and relatively mild clinical affection". All cases have been sporadic, implying that the risk of recurrence within a family may be low. Quite different clinical pictures, of considerably greater severity, are demonstrated in the remaining two cases. One had pontocerebellar hypoplasia type 2, while the other had a complex cerebellar and cerebral malformation.

Defining mechanisms of toxicity for linoleic acid monoepoxides and diols in Sf-21 cells.

Linoleic acid monoepoxides have been correlated with many pathological conditions. Studies using insect cells derived from Spodoptera frugiperda (Sf-21 cells) have suggested that conversion of the epoxides to the diols is required for toxicity. However, more recent studies using rabbit renal proximal tubules have suggested that linoleic acid monoepoxides are direct mitochondrial toxins. To better understand these discrepancies, we compared the toxicity of these linoleic acid metabolites in Sf-21 cells using mitochondrial respiration as an end point. Linoleic acid (100 microM) and 12,13-epoxy-9-octadecenoic acid (12,13-EOA, 100 microM) increased the rate of oligomycin-insensitive respiration by approximately 3.5- and 3-fold, respectively, decreased the rate of oligomycin-sensitive respiration by approximately 52 and 68%, respectively, and had no effect on the integrity of the electron transport chain. These effects were concentration-dependent, occurred within 1 min, and recovered to basal levels within 45 min. 12,13-Dihydroxy-9-octadecenoic acid (12,13-DHOA, 100 microM) had no effect on oligomycin-insensitive respiration but decreased the rate of oligomycin-sensitive respiration and uncoupled respiration in a concentration-dependent manner. Approximately 79 and 68% of oligomycin-sensitive respiration and uncoupled respiration was inhibited by 12,13-DHOA (100 microM), respectively. These effects occurred within 1 min and were not reversible in 6 h. Effects similar to those induced by 12,13-DHOA (100 microM) were observed using 12,13-EOA (100 microM) in Sf-21 cells expressing human soluble epoxide hydrolase. These data suggest that in this Sf-21 model linoleic acid and linoleic monoepoxides have transient uncoupling effects, whereas the primary mechanism of toxicity for linoleic acid diols in this model is inhibition of the electron transport chain.

Analysis of the cytotoxic properties of linoleic acid metabolites produced by renal and hepatic P450s.

Cytochrome P450 epoxidation of linoleic acid produces biologically active metabolites which have been associated with many pathological conditions that often lead to acute renal failure. In the present study, we evaluated the ability of specific cytochrome P450s to produce linoleic acid monoepoxides. We then tested the cytotoxic properties of linoleic acid, linoleic acid monoepoxides, and corresponding diols in a rabbit renal proximal tubule model. CYP1A2, CYP2E1, CYP2J2, CYP2J3, CYP2J5, and CYP2J9 metabolized linoleic acid at rates comparable to arachidonic acid and produced linoleic acid monoepoxides as major products. Cytotoxicity studies showed that linoleic acid, linoleic acid monoepoxides, and corresponding diols are toxic at pathologically relevant concentrations (100-500 microM). Concentration-dependent studies showed that linoleic acid and linoleic acid monoepoxides are the most toxic and induce mitochondrial dysfunction prior to cell death. Cytoprotectants known to block cell death associated with mitochondrial dysfunction and oxidative stress did not prevent cell death induced by linoleic acid and linoleic acid monoepoxides. This study shows that P450s in the CYP1 and CYP2 gene families metabolize linoleic acid to linoleic acid monoepoxides and that the monoepoxides, as well as linoleic acid, disrupt mitochondrial function without causing oxidative stress.

Cross-reactive rubella virus and glutamic acid decarboxylase (65 and 67) protein determinants recognised by T cells of patients with type I diabetes mellitus.

AIMS/HYPOTHESIS: To examine the cross-reaction between viral and beta-cell protein determinants and to further understand the potential role of this mechanism in Type I (insuline-dependent) diabetes mellitus. METHODS: Immune responses to a panel of 28 viral and beta-cell protein peptides representing selected sequences of rubella virus (RV), Coxsackie virus, human 38 KDa31G and glutamic acid decarboxylase (GAD 65 and 67) proteins in proliferation or cytotoxicity assays have been studied using uncloned and cloned T-cell cohorts from a group of 60 Type I diabetic patients. RESULTS: Peptide GAD65(252-266) induced the responses of patients with recent onset diabetes in proliferation assays at the highest frequency (77%), whereas GAD67(212-226) stimulated the cellular responses at the highest rate (61%) in patients with late-onset diabetes. RVE1(157-176) was recognised by all groups of patients at the highest frequency and the largest amplitude among the viral peptides tested. T-cell clones specific to GAD65(252-266), GAD65(274-286) or GAD67(212-226) were tested in cytotoxicity assays for their responses to rubella virus peptides. Each of these T-cell clones cross-reacted with two to four rubella virus peptides, including RVE1(157-176) and RVE2(87-107). Analysis of the sequences of cross-reactive viral and glutamic acid decarboxylase antigens showed that these epitopes shared similar peptide binding motifs to HLA DR3/DR4. There is a statistically significant correlation between the response amplitude of patient's peripheral blood mononuclear cells to RVE1(157-176), RVE2(87-107) and GAD65(274-286) in patients with recent onset diabetes, and to RVE1(157-176) and GAD67(212-226) in patients with late onset diabetes. CONCLUSION/INTERPRETATION: Cross-reactive glutamic acid decarboxylase and rubella virus determinants identified by T-cell clones were also recognised at high frequencies by general T-cell populations of Type I diabetic patients.

Hippuric acid as a major excretion product associated with black tea consumption.

1. Nine habitual tea-drinking volunteers were recruited and asked to follow a low-polyphenol and low-caffeine diet for 6 days and to provide daily 24-h urine samples. On day 4 of the experiment strong black tea brewed under standardized conditions was re-introduced to the volunteers' diet. 2. 1H-NMR and HPLC profiling of the urine samples indicated that consumption of black tea (6-10 mugs per day) was associated with a significant (p = 0.00017) increase in hippuric acid excretion relative to control, increasing from 153-512 to 742-1374 mg day(-1). The excretion of substantial amounts of hippuric acid has not previously been associated with black tea consumption. 3. For some volunteers, the quantity of benzoic acid processed exceeded the acceptable daily intake (ADI), but this is not considered to constitute any hazard. 4. A mass-balance analysis indicated that the necessary quantity of benzoic acid could not be obtained from the contents of gallic acid, flavanols, flavonol glycosides and theaflavins in black tea even if 100% transformation was obtained, suggesting that the thearubigins (the major and chemically ill-defined polyphenols of black tea) may be an important source.

Antenatal diagnosis of subependymal heterotopia.

Subependymal heterotopia consist of gray matter nodules along the lateral ventricular walls and are associated with epilepsy and other cerebral malformations. Some cases have an X-linked inheritance, and early antenatal diagnosis of affected fetuses is important for appropriate management. We present a case of heterotopia diagnosed by sonography and MR imaging at 23 weeks' gestation and discuss the differential diagnosis, reviewing the evolution and imaging appearances of the germinal matrix and its implications for detection of heterotopia.