Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.
  • Biochemical investigation of human tumours in vivo with phosphorus-31 magnetic resonance spectroscopy.

    15 March 2018

    The bioenergetic state of 15 human tumours was examined with phosphorus-31 magnetic resonance spectroscopy. A striking diversity in metabolic patterns was observed, and significant differences from normal tissue were seen in all cases. A common feature was an elevation of intracellular pH, which may be related to an increase in Na+/H+ exchange during cell activation. It is unlikely that the patterns observed directly correlate with malignancy, but characterisation of the energetic state of a given tumour in a given physiological environment may help in the design and evaluation of interventions for that specific case.

  • EFNS guidelines on the diagnostic approach to pauci- or asymptomatic hyperCKemia.

    11 May 2018

    OBJECTIVE: To provide evidence-based guidelines to general neurologists for the assessment of patients with pauci- or asymptomatic hyperCKemia. BACKGROUND: Recent epidemiologic studies show that up to 20% of 'normal' individuals have an elevated creatine kinase activity in the serum (sCK). The possibility of a subclinical myopathy is often raised, and patients may be unnecessarily denied treatment with statins. SEARCH STRATEGY: Electronic databases including Medline, the Cochrane Library and the American Academy of Neurology were searched for existing guidelines. Articles dealing with series of patients investigated for asymptomatic/pauci-symptomatic hyperCKemia and articles dealing with myopathies that can present with asymptomatic hyperCKemia were identified and reviewed. RESULTS: The only guidelines found were those approved by the Italian Association of Myology Committee, and the only relevant articles identified describe class IV studies. RECOMMENDATIONS: HyperCKemia needs to be redefined as values beyond 1.5 times the upper limit of normal (which itself needs to be appropriately defined). Pauci- or asymptomatic hyperCKemia with no apparent medical explanation may be investigated with a muscle biopsy if one or more of the following are present; the sCK is >or=3x normal, the electromyogram is myopathic or the patient is <25 years of age. In addition, women with sCK<3 times normal may be offered DNA testing because of the possibility of carrying a dystrophin mutation.

  • Combinatorial glycoarray.

    16 March 2018

    Glycolipid-protein interactions are increasingly recognised as critical to numerous and diverse biological processes, including immune recognition, cell-cell signalling, pathogen adherence, and virulence factor binding. Previously, such carbohydrate-lectin interactions have been assessed in vitro largely by assaying protein binding against purified preparations of single glycolipids. Recent observations show that certain disease-associated autoantibodies and other lectins bind only to complexes formed by two different gangliosides. However, investigating such 1:1 glycolipid complexes can prove technically arduous. To address this problem, we have developed a semi-automated system for assaying lectin binding to large numbers of glycolipid complexes simultaneously. This employs an automated thin-layer chromatography sampler. Single glycolipids and their heterodimeric complexes are prepared in microvials. The autosampler is then used to print reproducible arrays of glycolipid complexes onto polyvinylidene difluoride membranes affixed to glass slides. A printing density of 300 antigen spots per slide is achievable. Following overnight drying, these arrays can then be probed with the lectin(s) of interest. Detection of binding is by way of a horseradish peroxidase-linked secondary antibody driving a chemiluminescent reaction rendered on radiographic film. Image analysis software can then be used to measure signal intensity for quantification.

  • Ganglioside antibodies and neuropathies.

    30 April 2018

    PURPOSE OF REVIEW: Continuing progress in the field of antiganglioside antibodies is expanding our comprehension of the pathogenesis of the inflammatory neuropathies. Recent studies have helped unravel all aspects of this process, addressing a range of subjects from the bacterial and host factors involved in antibody induction through to their pathogenic effects. RECENT FINDINGS: This review focuses on developments in the field over the past 18 months. Advances in our understanding of antibody induction, host risk factors, and pathogenic end effects are described systematically, and particular attention is given to the novel concept of ganglioside complexes. SUMMARY: The wealth of scientific data is now driving the design of novel, targeted therapies. This preclinical research is outlined and suggestions made as to how this might be translated into clinical practice.

  • Analysis of lectin binding to glycolipid complexes using combinatorial glycoarrays.

    10 May 2018

    Glycolipids are major components of the plasma membrane, interacting with themselves, other lipids, and proteins to form an array of heterogeneous domains with diverse biological properties. Considerable effort has been focused on identifying protein binding partners for glycolipids and the glycan specificity for these interactions, largely achieved through assessing interactions between proteins and homogenous, single species glycolipid preparations. This approach risks overlooking both the enhancing and attenuating roles of heterogeneous glycolipid complexes in modulating lectin binding. Here we report a simple method for assessing lectin-glycolipid interactions. An automatic thin-layer chromatography sampler is employed to create easily reproducible arrays of glycolipids and their heterodimeric complexes immobilized on a synthetic polyvinyl-difluoride membrane. This array can then be probed with much smaller quantities of reagents than would be required using existing techniques such as ELISA and thin-layer chromatography with immuno-overlay. Using this protocol, we have established that the binding of bacterial toxins, lectins, and antibodies can each be attenuated, enhanced, or unaffected in the presence of glycolipid complexes, as compared with individual, isolated glycolipids. These findings underpin the wide-ranging influence and importance of glycolipid-glycolipid cis interactions when the nature of protein-carbohydrate recognition events is being assessed.

  • Blood pleurodesis for the medical management of pneumothorax.

    26 April 2018

    Blood pleurodesis has been used to treat pneumothorax and persistent postoperative air leak following pneumonectomy. However, the indications for this procedure and the exact technique to be followed remain poorly defined. Having reviewed the current literature, a protocol is proposed for the technique and its complications and long-term outcomes are discussed.

  • The neuropathic potential of anti-GM1 autoantibodies is regulated by the local glycolipid environment in mice.

    16 March 2018

    Anti-GM1 ganglioside autoantibodies are used as diagnostic markers for motor axonal peripheral neuropathies and are believed to be the primary mediators of such diseases. However, their ability to bind and exert pathogenic effects at neuronal membranes is highly inconsistent. Using human and mouse monoclonal anti-GM1 antibodies to probe the GM1-rich motor nerve terminal membrane in mice, we here show that the antigenic oligosaccharide of GM1 in the live plasma membrane is cryptic, hidden on surface domains that become buried for a proportion of anti-GM1 antibodies due to a masking effect of neighboring gangliosides. The cryptic GM1 binding domain was exposed by sialidase treatment that liberated sialic acid from masking gangliosides including GD1a or by disruption of the live membrane by freezing or fixation. This cryptic behavior was also recapitulated in solid-phase immunoassays. These data show that certain anti-GM1 antibodies exert potent complement activation-mediated neuropathogenic effects, including morphological damage at living terminal motor axons, leading to a block of synaptic transmission. This occurred only when GM1 was topologically available for antibody binding, but not when GM1 was cryptic. This revised understanding of the complexities in ganglioside membrane topology provides a mechanistic account for wide variations in the neuropathic potential of anti-GM1 antibodies.

  • Antibodies to heteromeric glycolipid complexes in multifocal motor neuropathy.

    10 May 2018

    BACKGROUND: Measurement of anti-GM1 IgM antibodies in multifocal motor neuropathy (MMN) sera is confounded by relatively low sensitivity that limits clinical usefulness. Combinatorial assay methods, in which antibodies react to heteromeric complexes of two or more glycolipids, are being increasingly applied to this area of diagnostic testing. METHODS: A newly developed combinatorial glycoarray able to identify antibodies to 45 different heteromeric glycolipid complexes and their 10 individual glycolipid components was applied to a randomly selected population of 33 MMN cases and 57 normal or disease controls. Comparison with an enzyme-linked immunosorbent assay (ELISA) was conducted for selected single glycolipids and their complexes. RESULTS: By ELISA, 22/33 MMN cases had detectable anti-GM1 IgM antibodies, whereas 19/33 MMN samples were positive for anti-GM1 antibodies by glycoarray. Analysis of variance (anova) revealed that of the 55 possible single glycolipids and their 1:1 complexes, antibodies to the GM1:galactocerebroside (GM1:GalC) complex were most significantly associated with MMN, returning 33/33 MMN samples as positive by glycoarray and 29/33 positive by ELISA. Regression analysis revealed a high correlation in absolute values between ELISA and glycoarray. Receiver operator characteristic analysis revealed insignificantly different diagnostic performance between the two methods. However, the glycoarray appeared to offer slightly improved sensitivity by identifying antibodies in four ELISA-negative samples. CONCLUSIONS: The use of combinatorial glycoarray or ELISA increased the diagnostic sensitivity of anti-glycolipid antibody testing in this cohort of MMN cases, without significantly affecting specificity, and may be a useful assay modification for routine clinical screening.