The evolving role of neurological imaging in neuro-oncology.

Neuroimaging has played a critical role in the management of patients with neurological disease, since the first ventriculogram was performed in 1918 by Walter Dandy (Mezger et al. Langenbecks Arch Surg 398(4):501-514, 2013). Over the last century, technology has evolved significantly, and within the last decade, the role of imaging in the management of patients with neuro-oncologic disease has shifted from a tool for gross identification of intracranial pathology, to an integral part of real-time neurological surgery. Current neurological imaging provides detailed information about anatomical structure, neurological function, and metabolic and metabolism-important characteristics that help clinicians and surgeons non-invasively manage patients with brain tumors. It is valuable to review the evolution of neurological imaging over the past several decades, focusing on its role in the management of patients with intracranial tumors. Novel neuro-imaging tools and developing technology with the potential to further transform clinical practice will be discussed, as will the key role neurological imaging plays in neurosurgical planning and intraoperative navigation. With increasingly complex imaging modalities creating growing amounts of raw data, validation of techniques, data analysis, and integrating various pieces of imaging data into individual patient management plans, remain significant challenges for clinicians. We thus suggest mechanisms that might ultimately allow for evidence based integration of imaging in the management of patients with neuro-oncologic disease.

Feasibility of whole genome and transcriptome profiling in pediatric and young adult cancers.

The utility of cancer whole genome and transcriptome sequencing (cWGTS) in oncology is increasingly recognized. However, implementation of cWGTS is challenged by the need to deliver results within clinically relevant timeframes, concerns about assay sensitivity, reporting and prioritization of findings. In a prospective research study we develop a workflow that reports comprehensive cWGTS results in 9 days. Comparison of cWGTS to diagnostic panel assays demonstrates the potential of cWGTS to capture all clinically reported mutations with comparable sensitivity in a single workflow. Benchmarking identifies a minimum of 80× as optimal depth for clinical WGS sequencing. Integration of germline, somatic DNA and RNA-seq data enable data-driven variant prioritization and reporting, with oncogenic findings reported in 54% more patients than standard of care. These results establish key technical considerations for the implementation of cWGTS as an integrated test in clinical oncology.

Manganese superoxide dismutase expression in human central nervous system tumors.

Manganese superoxide dismutase (MnSOD) is a superoxide anion scavenger located in mitochondria. Increased expression of MnSOD can diminish oxygen radical-mediated injuries and the cytotoxic effects of tumor necrosis factor alpha, ionizing radiation, and certain chemotherapeutic agents. We used immunohistochemical staining to analyze 42 specimens of human brain tumors and 3 normal brain controls with a polyclonal antibody recognizing human MnSOD. We measured MnSOD in cerebrospinal fluid (CSF) from 14 patients with brain tumors and 7 control patients using an ELISA. Although MnSOD is not readily detected in normal brain, malignant central nervous system tumors, including tumors metastatic to the brain, displayed marked immunoreactivity to MnSOD intracellularly, in the extracellular matrix and in the tumor endothelial cells. Grade IV astrocytomas (glioblastomas), Grade III astrocytomas, and medulloblastomas were strongly immunoreactive, whereas Grade II astrocytomas had much less immunoreactivity. ELISA analysis of CSF samples from patients with malignant tumors also revealed high levels of MnSOD protein, up to 45-fold greater than the level of control CSF samples.

Expression of nitric oxide synthase in human central nervous system tumors.

The nitric oxide synthases (NOS) are a family of related enzymes which regulate the production of NO, a free radical gas implicated in a wide variety of biological processes. Vasodilation and increased tumor blood flow, increased vascular permeability, modulation of host tumoricidal activity, and free radical injury to tumor cells and adjacent normal tissues are pathophysiological features of malignant tumors that may be mediated by NO. We examined human brain tumors for three NOS isoforms and NADPH diaphrase, a histochemical marker of NOS activity in the brain. We detected increased expression of the brain and endothelial forms of NOS [NOS I and NOS II, respectively (C. Nathan and Q. Xie. Cell, 78: 915-919, 1994)] in astrocytic tumors, and the highest levels of expression was found in higher grade tumors. Each of these two isoforms was found in tumor cells and tumor endothelial cells. The macrophage isoform of NOS (NOS III) was less frequently detected and expressed at a lower level, predominantly in tumor endothelial cells. NADPH diaphorase staining for NOS activity paralleled this pattern of NOS expression. Western blot analysis of tumor tissues for these NOS isoforms confirmed these observations. Our data indicate that malignant central nervous system neoplasms express unexpectedly high levels of NOS and suggest that NO production may be associated with pathophysiological processes important to these tumors.

Human cytomegalovirus infection and expression in human malignant glioma.

Malignant gliomas are the most common primary brain tumors in adults, have no known etiology, and are generally rapidly fatal despite current therapies. Human cytomegalovirus (HCMV) is beta-herpesvirus trophic for glial cells that persistently infects 50-90% of the adult human population. HCMV can be reactivated under conditions of inflammation and immunosuppression, and HCMV gene products can dysregulate multiple cellular pathways involved in oncogenesis. Here we show that a high percentage of malignant gliomas are infected by HCMV and multiple HCMV gene products are expressed in these tumors. These data are the first to show an association between HCMV and malignant gliomas and suggest that HCMV may play an active role in glioma pathogenesis.

Second messengers regulate RGS2 expression which is targeted to the nucleus.

Regulators of G-protein Signaling (RGS) proteins attenuate signaling activities of G proteins, and modulation of expression appears to be a primary mechanism for regulating RGS proteins. In human astrocytoma 1321N1 cells RGS2 expression was increased by activation of muscarinic receptors coupled to phosphoinositide signaling with carbachol, or by increased cyclic AMP production, demonstrating that both signaling systems can increase the expression of a RGS family member in a single cell type. Carbachol-stimulated increases in endogenous RGS2 protein levels appeared by immunocytochemical analysis to be largely confined to the nucleus, and this localization was confirmed by Western blot analysis which showed increased nuclear, but not cytosolic, RGS2 after carbachol treatment. Additionally, transiently expressed green fluorescent protein (GFP)-tagged, 6xHis-tagged, or unmodified RGS2 resulted in a predominant nuclear localization, as well as a distinct accumulation of RGS2 along the plasma membrane. The intranuclear localization of GFP-RGS2 was confirmed with confocal microscopy. Thus, RGS2 expression is rapidly and transiently increased by phosphoinositide signaling and by cyclic AMP, and endogenous and transfected RGS2 is largely, although not entirely, localized in the nucleus.

Failure of colchicine in the treatment of Mollaret's meningitis.

A 32-year-old man was hospitalized 23 times in 11 years because of attacks of Mollaret's meningitis. Colchicine (0.6 mg twice daily) was administered for 15 months but failed to decrease the severity or the frequency of attacks. The prophylactic efficacy of drugs in Mollaret's meningitis is difficult to assess because episodes are unpredictable and remissions occur spontaneously. There remains no established therapy for Mollaret's meningitis.

Infections from Body Piercing and Tattoos.

The infectious complications of body piercing and tattooing are reviewed.

Repetitive intrathecal injections of poliovirus replicons result in gene expression in neurons of the central nervous system without pathogenesis.

Poliovirus-based vectors (replicons) can be used for gene delivery to motor neurons of the CNS. In the current study, a replicon encoding green fluorescent protein (GFP) was encapsidated into authentic poliovirions, using established procedures. Intrathecal delivery of encapsidated replicons encoding GFP to the CNS of mice transgenic for the human poliovirus receptor did not result in any functional deficits as judged by behavioral testing. Histological analysis of the CNS of mice given a single intrathecal injection of poliovirus replicons encoding GFP revealed no obvious pathogenesis in neurons (or other cell types) within the CNS. The expression of GFP was confined to motor neurons throughout the neuroaxis; a time course of expression of GFP revealed that expression was detectable 24 hr postinoculation and returned to background levels by 120 hr postinoculation. A procedure was devised to allow repetitive inoculation of replicons within the same animal. Behavioral testing of animals that had received 6 to 13 independent inoculations of replicons revealed no functional deficits. Histological analysis of the CNS from animals that had received 6 to 13 sequential inoculations of replicons revealed no obvious abnormalities in neurons or other cell types in the CNS; expression of GFP was demonstrated in neurons 24 to 72 hr after the final inoculation of the replicon. Furthermore, there was no obvious inflammatory response in the CNS after the multiple inoculations. These studies establish the safety and efficacy of replicons for gene delivery to the CNS and are discussed with respect to use of replicons as new therapeutic strategies for spinal cord injuries and/or neurological diseases.

Persistent bacteremia in staphylococcal endocarditis.

We treated five patients with persistent Staphylococcus aureus bacteremia and endocarditis. Surgical intervention or a "second-line" antistaphylococcal agent was required for bacteriologic cure in each. Special bacteriologic evaluation failed to demonstrate methicillin resistance or antibiotic "tolerance" among the strains of Staphylococcus tested. Cephalosporin agents were noted to be more susceptible to inoculum effect than either methicillin or nafcillin. All patients survived; the explanation for their atypical course is obscure. We present an approach to patients with persistent Staph. aureus bacteremia and endocarditis.

Indications for cardiac surgery in patients with active infective endocarditis.

Currently, absolute indications for valve replacement during active infective endocarditis include severe heart failure, the presence of an infecting microorganism that is not susceptible to available antimicrobial agents, and, in patients with an infected prosthetic valve, an unstable device. Relative indications include an etiologic microorganism other than a susceptible Streptococcus, relapse after presumed effective therapy, evidence of intracardiac extension of the infection, two or more systemic emboli, vegetations large enough to be demonstrated by echocardiography, and, in patients with an infected prosthetic device, early disease and periprosthetic leak. With use of data from the medical literature, a study generated by the cardiovascular surgical group at the University of Alabama School of Medicine, and a brief cost analysis, a point system was constructed to assist in decision-making concerning surgery in patients with active infective endocarditis. The usefulness of this system will depend on experience generated from its utilization in a larger number of patients as well as new data relative to a more complete understanding of the risks and benefits of surgery in this condition.

Effects of a decision support system on physicians' diagnostic performance.

PURPOSE: This study examines how the information provided by a diagnostic decision support system for clinical cases of varying diagnostic difficulty affects physicians' diagnostic performance. METHODS: A national sample of 67 internists, 35 family physicians, and 6 other physicians used the Quick Medical Reference (QMR) diagnostic decision support system to assist them in the diagnosis of written clinical cases. Three sets of eight cases, stratified by diagnostic difficulty and the potential of QMR to produce high-quality information, were used. The effects of using QMR on three measures of physicians' diagnostic performance were analyzed using analyses of variance. RESULTS: Physicians' diagnostic performance was significantly higher (p < 0.01) on the easier cases and the cases for which QMR could provide higher-quality information. CONCLUSIONS: Physicians' diagnostic performance can be strongly influenced by the quality of information the system produces and the type of cases on which the system is used.

Bacteriostatic versus bactericidal activity.

Antibiotics alone or in combination may either inhibit or kill bacteria. Laboratory methods are available to determine the activity of various antimicrobial agents and can aid the physician in selecting appropriate antimicrobial therapy for specific infectious disease disorders. A few infectious processes appear to require bactericidal antimicrobial therapy for cure. Additional multicenter trials of the ability of a standardized SBT to predict therapeutic outcome in specific bacterial diseases are required.

The newer cephalosporins. Aztreonam and imipenem.

Many of the antimicrobial agents described here exhibit great advances over older drugs in terms of antimicrobial spectrum, clinical utility, and, sometimes, safety. The newer cephalosporins are useful for treatment of many common outpatient and inpatient infections. Aztreonam provides excellent coverage against a broad range of aerobic gram-negative bacteria, without the toxicity associated with aminoglycosides. Imipenem exhibits activity against an impressive array of pathogens. These antimicrobials are expensive, however, and some offer no advantages over older agents. Finally, all--including imipenem--are faced with increasing resistance of bacteria.

Expression of nitric oxide synthase in the cerebral microvasculature after traumatic brain injury in the rat.

Reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPHd) histochemistry and nitric oxide synthase (NOS) immunocytochemistry were performed on sections of brain after moderate traumatic brain injury. There was a pronounced increase in NADPHd reactivity and an induction of the endothelial NOS (eNOS) isoform in microvessels surrounding the cortical contusion by 24 h post-injury. This altered microvascular state may contribute to barrier breakdown and hyperemia which characterize traumatic brain injury.

Hypoxic induction of vascular endothelial growth factor (VEGF) protein in astroglial cultures.

Vascular endothelial growth factor (VEGF) couples hypoxia to angiogenesis in ischemic tissues, including brain. Since hypoxia induces VEGF mRNA in astroglial cultures, we examined its effect on VEGF protein, measured by ELISA, in medium from cultures exposed to 95% N2/5% CO2 for up to 24 h. Levels increased with increasing durations of hypoxia, but not glucose deprivation, reaching approximately 30-fold elevation by 24 h. Co2+ and desferrioxamine also increased VEGF levels, while inhibitors of RNA or protein synthesis blocked induction. These findings support a role for astroglia in the hypoxic induction of VEGF expression and release-and potentially angiogenesis-in the ischemic brain.

Vascular endothelial growth factor expression in transient focal cerebral ischemia in the rat.

Vascular endothelial growth factor (VEGF) has been implicated in hypoxia-induced angiogenesis in tumors and ischemia. We examined VEGF mRNA and protein expression after occlusion of the middle cerebral artery (MCA) in rats. VEGF mRNA expression studied by in situ hybridization was increased in the ischemic border zone 24 h after 30, 60 or 120 min of focal cerebral ischemia. VEGF protein expression measured by Western blots was also increased in this region 24 and 48 h after ischemia, and VEGF immunocytochemistry localized this increased expression to astroglia. Thus, VEGF is induced after focal cerebral ischemia and could have a role in pathophysiology and recovery in the ischemic border zone.

Immobilization of enzymes with polyaziridines.

A novel method of enzyme immobilization using a low molecular weight prepolymer of tri-functional aziridines which can immobilize enzymes both by covalent attachment and entrapment within a gel matrix is described. The enzymes are immobilized on a solid support and exhibit an excellent retention of enzymatic activity. The immobilization procedure is essentially a single step process which can be easily performed at room temperature or 4 degrees C in either aqueous solution or in an inert organic solvent. The polyaziridines used in the immobilization are nontoxic, available in bulk at low cost and completely miscible with water and many organic solvents, thus providing one of the most satisfactory methods of immobilization available.

The "presyrinx" state: a reversible myelopathic condition that may precede syringomyelia.

BACKGROUND AND PURPOSE: Alteration of CSF flow has been proposed to be an important mechanism leading to the development of syringomyelia. We hypothesize that a "presyrinx" condition attributable to a potentially reversible alteration in normal CSF flow exists and that its appearance may be caused by variations in the competence of the central canal of the spinal cord. METHODS: Five patients with clinical evidence of myelopathy, no history of spinal cord trauma, enlargement of the cervical spinal cord with T1 and T2 prolongation but no cavitation, evidence of altered or obstructed CSF flow, and no evidence of intramedullary tumor or a spinal vascular event underwent MR imaging before and after intervention that alleviated obstruction to CSF flow. RESULTS: Preoperatively, all patients had enlarged spinal cords and parenchymal T1 and T2 prolongation without cavitation. Results of MR examinations after intervention showed resolution of cord enlargement and normalization or improvement of cord signal abnormalities. In one patient with severe arachnoid adhesions who initially improved after decompression, late evolution into syringomyelia occurred in association with continued CSF obstruction. CONCLUSION: Nontraumatic obstruction of the CSF pathways in the spine may result in spinal cord parenchymal T2 prolongation that is reversible after restoration of patency of CSF pathways. We refer to this MR appearance as the "presyrinx" state and stress the importance of timely intervention to limit progression to syringomyelia.

Detection of common antigenic sites in lethal proteins of non-related animal venoms.

Monoclonal antibodies neutralizing specific coelenterate lethal toxins were used to determine the presence of homologous antigenic sites on toxin proteins of a rattlesnake (Crotalus durissus terrificus), a hornet (Vespa orientalis) and the sea wasp (Chironex fleckeri). An anti-Portuguese man-o'war toxin antibody was found useful for isolating a C. d. terrificus toxin.