Penumbral cooling in ischemic stroke with intraarterial, intravenous or active conductive head cooling: A thermal modeling study

In ischemic stroke, selectively cooling the ischemic penumbra might lead to neuroprotection while avoiding systemic complications. Because penumbral tissue has reduced cerebral blood flow and in vivo brain temperature measurement remains challenging, the effect of different methods of therapeutic hypothermia on penumbral temperature are unknown. We used the COMSOL Multiphysics® software to model a range of cases of therapeutic hypothermia in ischemic stroke. Four ischemic stroke models were developed with ischemic core and/or penumbra volumes between 33-300 mL. Four experiments were performed on each model, including no cooling, and intraarterial, intravenous, and active conductive head cooling. The steady-state temperature of the non-ischemic brain, ischemic penumbra, and ischemic core without cooling was 37.3 °C, 37.5-37.8 °C, and 38.9-39.4 °C respectively. Intraarterial, intravenous and active conductive head cooling reduced non-ischemic brain temperature by 4.3 °C, 2.1 °C, and 0.7-0.8 °C respectively. Intraarterial, intravenous and head cooling reduced the temperature of the ischemic penumbra by 3.9-4.3 °C, 1.9-2.1 °C, and 1.2-3.4 °C respectively. Active conductive head cooling was the only method to selectively reduce penumbral temperature. Clinical studies that measure brain temperature in ischemic stroke patients undergoing therapeutic hypothermia are required to validate these hypothesis-generating findings.

Diversification and expansion of the EBV-reactive cytotoxic T lymphocyte repertoire following autologous haematopoietic stem cell transplant for multiple sclerosis

Both genetic susceptibility and environmental exposures are thought to be involved in multiple sclerosis (MS) pathogenesis. Of all viruses potentially relevant to MS aetiology, Epstein-Barr virus (EBV) is the best-studied. EBV is a B cell lymphotropic virus which is able to evade the immune system by establishing latent infection in memory B cells, and EBV reactivation is restricted by CD8 cytotoxic T cell (CTL) responses in immune competent individuals. Autologous haematopoietic stem cell transplantation (AHSCT) is considered to be the most effective therapy in the treatment of relapsing MS even though chemotherapy-induced lymphopenia can associate with the re-emergence of latent viruses. Despite the increasing interest in EBV and MS pathogenesis the relationship between AHSCT, EBV and viral immunity in people with MS has not been investigated to date. This study analysed immune responses to EBV in a well characterised cohort of 13 individuals with MS by utilising pre-AHSCT, and 6-, 12- and 24-month post AHSCT bio-banked peripheral blood mononuclear cells and plasma samples. It is demonstrated that the infused stem cell product contains latently EBV-infected memory B cells, and that EBV viremia occurs in the immune-compromised recipient post-transplant. High throughput TCR analysis detected expansion and diversification of the CD8 CTL responses reactive with EBV lytic and latent antigens from 6 to 24 months following AHSCT. Increased levels of latent EBV infection found within the B cell pool following treatment, as measured by EBV genomic detection, did not associate with disease relapse. This is the first study of EBV immunity following application of AHSCT in the treatment of MS and not only raises important questions about the role of EBV infection in MS pathogenesis, but is of clinical importance given the expanding clinical trials of adoptive EBV-specific CTLs in MS.

From bedside to bench: how existing therapies inform the relationship between Epstein-Barr virus and multiple sclerosis

Therapy for relapsing-remitting multiple sclerosis (MS) has advanced dramatically despite incomplete understanding of the cause of the condition. Current treatment involves inducing broad effects on immune cell populations with consequent off-target side effects, and no treatment can completely prevent disability progression. Further therapeutic advancement will require a better understanding of the pathobiology of MS. Interest in the role of Epstein-Barr virus (EBV) in multiple sclerosis has intensified based on strong epidemiological evidence of an association between EBV seroprevalence and MS. Hypotheses proposed to explain the biological relationship between EBV and MS include molecular mimicry, EBV immortalised autoreactive B cells and infection of glial cells by EBV. Examining the interaction between EBV and immunotherapies that have demonstrated efficacy in MS offers clues to the validity of these hypotheses. The efficacy of B cell depleting therapies could be consistent with a hypothesis that EBV-infected B cells drive MS; however, loss of T cell control of B cells does not exacerbate MS. A number of MS therapies invoke change in EBV-specific T cell populations, but pathogenic EBV-specific T cells with cross-reactivity to CNS antigen have not been identified. Immune reconstitution therapies induce EBV viraemia and expansion of EBV-specific T cell clones, but this does not correlate with relapse. Much remains unknown regarding the role of EBV in MS pathogenesis. We discuss future translational research that could fill important knowledge gaps.

A novel RFC1 repeat motif (ACAGG) in two Asia-Pacific CANVAS families

Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is a progressive late-onset, neurological disease. Recently, a pentanucleotide expansion in intron 2 of RFC1 was identified as the genetic cause of CANVAS. We screened an Asian-Pacific cohort for CANVAS and identified a novel RFC1 repeat expansion motif, (ACAGG)exp, in three affected individuals. This motif was associated with additional clinical features including fasciculations and elevated serum creatine kinase. These features have not previously been described in individuals with genetically-confirmed CANVAS. Haplotype analysis showed our patients shared the same core haplotype as previously published, supporting the possibility of a single origin of the RFC1 disease allele. We analysed data from >26 000 genetically diverse individuals in gnomAD to show enrichment of (ACAGG) in non-European populations.

A Māori specific RFC1 pathogenic repeat configuration in CANVAS, likely due to a founder allele

Cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS) is a recently recognized neurodegenerative disease with onset in mid- to late adulthood. The genetic basis for a large proportion of Caucasian patients was recently shown to be the biallelic expansion of a pentanucleotide (AAGGG)n repeat in RFC1. Here, we describe the first instance of CANVAS genetic testing in New Zealand Māori and Cook Island Māori individuals. We show a novel, possibly population-specific CANVAS configuration (AAAGG)10-25(AAGGG)exp, which was the cause of CANVAS in all patients. There were no apparent phenotypic differences compared with European CANVAS patients. Presence of a common disease haplotype among this cohort suggests this novel repeat expansion configuration is a founder effect in this population, which may indicate that CANVAS will be especially prevalent in this group. Haplotype dating estimated the most recent common ancestor at ∼1430 ce. We also show the same core haplotype as previously described, supporting a single origin of the CANVAS mutation.

Cerebellar ataxia, neuropathy, vestibular areflexia syndrome due to RFC1 repeat expansion

Ataxia, causing imbalance, dizziness and falls, is a leading cause of neurological disability. We have recently identified a biallelic intronic AAGGG repeat expansion in replication factor complex subunit 1 (RFC1) as the cause of cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) and a major cause of late onset ataxia. Here we describe the full spectrum of the disease phenotype in our first 100 genetically confirmed carriers of biallelic repeat expansions in RFC1 and identify the sensory neuropathy as a common feature in all cases to date. All patients were Caucasian and half were sporadic. Patients typically reported progressive unsteadiness starting in the sixth decade. A dry spasmodic cough was also frequently associated and often preceded by decades the onset of walking difficulty. Sensory symptoms, oscillopsia, dysautonomia and dysarthria were also variably associated. The disease seems to follow a pattern of spatial progression from the early involvement of sensory neurons, to the later appearance of vestibular and cerebellar dysfunction. Half of the patients needed walking aids after 10 years of disease duration and a quarter were wheelchair dependent after 15 years. Overall, two-thirds of cases had full CANVAS. Sensory neuropathy was the only manifestation in 15 patients. Sixteen patients additionally showed cerebellar involvement, and six showed vestibular involvement. The disease is very likely to be underdiagnosed. Repeat expansion in RFC1 should be considered in all cases of sensory ataxic neuropathy, particularly, but not only, if cerebellar dysfunction, vestibular involvement and cough coexist.

Review article: the changing epidemiology of hepatocellular carcinoma in Canada

The aim of this study was to examine the incidence of and mortality caused by hepatocellular carcinoma over the last 20 years in Canada, including the associated risk factors hepatitis C, diabetes and obesity. Databases from the Surveillance & Risk Assessment Division of Health Canada & Statistics Canada were analysed for trends in both age-adjusted incidence of and mortality due to hepatocellular carcinoma from 1984 to 2001. The epidemiological impact of hepatitis C, diabetes and obesity on hepatocellular carcinoma was also assessed. The incidence of hepatocellular carcinoma increased from 4.0 per 100,000 in 1984 to 5.5 in 2,000 for males, and from 1.6 per 100,000 in 1984 to 2.2 in 2,000 for females. Mortality rates showed a 48% increase in males and 39% increase in females. The incidence of hepatitis C increased sharply in 1995 and remained elevated until 2,000 with an average value of 85.4 per 100,000 in males and 45.4 per 100,000 in females. This increase is likely due to the widespread testing for hepatitis C. The prevalence of obesity and diabetes has increased in recent years and probably contributes to the increased incidence of hepatocellular carcinoma. The incidence of hepatocellular carcinoma in Canada has increased in the past 20 years and is associated with a rise in the incidence of hepatitis C, obesity and diabetes.

Hypersensitivity pneumonitis from Pezizia domiciliana. A case of El Niño lung

A previously healthy woman developed severe dyspnea and was found to have restrictive lung disease and evidence of alveolitis. Open lung biopsy revealed extrinsic allergic alveolitis (hypersensitivity pneumonitis). The etiology was not initially apparent, but a home inspection showed an unusual mushroom growing in the patient's basement. Air sampling and serum precipitins against the fungal antigens confirmed that Pezizia domiciliana was the cause of the patient's hypersensitivity pneumonitis. This is the first described case of hypersensitivity pneumonitis cause by P. domiciliana. We speculate that unprecedented rainfall and flooding of the patient's basement as a result of El Niño rains produced ideal factors for the growth of this fungus.

Polymyalgia, hypersensitivity pneumonitis and other reactions in patients receiving HMG-CoA reductase inhibitors: a report of ten cases

Ten patients who take hydroxy-methylglutaryl coenzyme A reductase inhibitors, or statin medications, and experience adverse reactions are described. All patients experienced various manifestations of hypersensitivity while receiving the drugs. One patient is described with hypersensitivity pneumonitis, which was graphically demonstrated by both high resolution computerized axial tomography and open lung biopsy.

The effect of dapsone in steroid-dependent asthma

We studied the steroid-sparing effect of dapsone in 10 subjects with chronic asthma in a preliminary open trial. Dapsone was chosen because it inhibits neutrophil function and possesses anti-inflammatory effects in a variety of disorders. The study group consisted of 10 subjects with stable, steroid-dependent asthma, aged 23 to 80 years, with normal glucose-6-phosphate dehydrogenase levels. Average daily baseline prednisone dose ranged from 5 to 60 mg. Dapsone, 100 mg, twice daily, by mouth, was started after a 1-month baseline period. Baseline steroid dose, symptom scores, and daily peak flow rates were compared to the latest available 4-week period of dapsone treatment. Average cumulative monthly prednisone dose was reduced from 428 mg to 82 mg (p less than 0.02). Five of 10 patients stopped steroids by month 6 and two additional patients by month 13. Two additional patients demonstrated a coincidental 74% reduction in steroid dose, and one patient demonstrated no response. Clinical parameters remained stable despite steroid reduction. These preliminary data suggest dapsone may have steroid-sparing effects in chronic asthma.