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Biomedical subjects

John H J Wokke

Publications and source records attributed to John H J Wokke.

At least 19 recordsLinked to original sources
PubMed2007

The association between H63D mutations in HFE and amyotrophic lateral sclerosis in a Dutch population.

BACKGROUND: Mutations in HFE, a gene defect that can disrupt iron metabolism, have been implicated in increasing the risk of developing amyotrophic lateral sclerosis (ALS). OBJECTIVE: To further establish the association between ALS and HFE mutations by investigating whether HFE mutations are associated with an increased risk of developing ALS in a population in The Netherlands and by pooling our results with those from previous studies. DESIGN: Retrospective study. SETTING: Tertiary referral center for neuromuscular disorders. PARTICIPANTS: Genotyping for 2 common HFE mutations was performed in 289 patients with ALS and 5886 population-based controls in The Netherlands between January 1, 2000, and December 31, 2004. MAIN OUTCOME MEASURES: Development of ALS and clinical phenotype were compared among the different HFE genotypes, adjusting for known prognostic factors such as age at onset and sex. RESULTS: Homozygosity for H63D was associated with an increased risk of developing ALS (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.1-4.1). After pooling our results with those from previous studies, a positive association between H63D homozygotes (OR, 2.7; 95% CI, 1.7-4.4), heterozygotes (OR, 1.5; 95% CI, 1.0-2.1), and mutation carriers (OR, 1.7; 95% CI, 1.1-2.5) was found. Within the patient group, heterozygosity for the H63D mutation was associated with a higher age at onset. CONCLUSIONS: These findings suggest that H63D mutations in HFE play a role in the pathogenesis of ALS in various populations. This association might involve a later-onset subset of ALS.

Adult↗
PubMed2006

Leukocyte and complement activation by GM1-specific antibodies is associated with acute motor axonal neuropathy in rabbits.

Acute motor axonal neuropathy (AMAN) in humans is associated with the presence of GM1-specific antibodies. Immunization of rabbits with GM1-containing ganglioside mixtures, purified GM1, or Campylobacter jejuni lipo-oligosaccharide exhibiting a GM1-like structure elicits GM1-specific antibodies, but axonal polyneuropathy only occurs in a subset of animals. This study aimed to dissect the molecular basis for the variable induction of AMAN in rabbits. Therefore, we analyzed the pro-inflammatory characteristics of GM1-specific antibodies in plasma samples from ganglioside-immunized rabbits with and without neurological deficits. GM1-specific plasma samples from all rabbits with AMAN were capable of activating both complement and leukocytes, in contrast to none of the plasma samples from rabbits without paralysis. Furthermore, GM1-specific IgG-mediated activation of leukocytes was detected before the onset of clinical signs. These data suggest that AMAN only occurs in rabbits that develop GM1-specific antibodies with pro-inflammatory properties.

Acute Disease↗
PubMed2006

Ganglioside-specific IgG and IgA recruit leukocyte effector functions in Guillain-Barré syndrome.

The capacity of ganglioside-specific autoantibodies to recruit leukocyte effector functions was studied. Serum samples from 87 patients with Guillain-Barré (GBS) or Miller Fisher syndrome (MFS), containing GM1-, GQ1b-, or GD1b-specific IgG or IgA, were tested for leukocyte activating capacity. Ganglioside-specific IgG antibodies generally induced leukocyte activation, irrespective of specificity. The magnitude of leukocyte degranulation correlated with GM1- and GQ1b-specific IgG titers, but not with disease severity. Finally, GM1-specific IgA activated leukocytes through the IgA receptor, FcalphaRI (CD89). Therefore, both ganglioside-specific IgG and IgA can recruit leukocyte effector functions, which may be relevant in the pathogenesis of GBS and MFS.

Adolescent↗
PubMed2006

Immunoglobulin gene analysis in polyneuropathy associated with IgM monoclonal gammopathy.

Antineural antibody activity is the implicated pathogenic mechanism in polyneuropathy associated with monoclonal gammopathy. Recognition of antigen depends on immunoglobulin variable regions, encoded by V genes. We studied V(H)DJ(H) and V(L)J(L) gene use in monoclonal B cells by clonal analysis in 20 patients with polyneuropathy and IgM monoclonal gammopathy. V genes associated with bacterial responses appear over-represented and V(H)3-23 was preferentially used, without association with specific D, J(H) or V(L)J(L). V genes revealed somatic mutation and intraclonal variation was found in 9 of 20 patients. Polyneuropathy associated with monoclonal gammopathy may be caused by an immune response to bacterial antigens, which recruit somatically mutated autoreactive B cells.

Aged↗
PubMed2006

Effect of non-invasive ventilation on survival, quality of life, respiratory function and cognition: a review of the literature.

Symptoms of nocturnal hypoventilation may negatively influence the quality of life (QoL) of ALS patients long before respiratory failure ensues. Non-invasive mechanical ventilation (NIV) is considered a treatment option for nocturnal hypoventilation. The primary objective of NIV is improving quality of life (QoL). It may also prolong life by several months. A systematic review of the literature was performed to analyse what is known of the effect of NIV on survival, QoL and other outcome measures. A computerized literature search was performed to identify controlled clinical trials and observational studies of treatment of ALS-associated nocturnal hypoventilation from 1985 until May 2005. Twelve studies fulfilled the inclusion criteria. Four studies were retrospective, seven prospective and in one study randomization was used. All studies reported beneficial effects of NIV on all outcome measures. In seven studies NIV was associated with prolonged survival in patients tolerant for NIV, and five studies reported an improved QoL. In conclusion, studies on the use of NIV in ALS differ in study design and endpoint definitions. All studies suggest a beneficial effect on QoL and other outcome measures (Evidence level Class II-III). Well-designed randomized controlled trials comparing the effect on QoL and survival have not been performed.

Amyotrophic Lateral Sclerosis↗
PubMed2006

Chip-based mtDNA mutation screening enables fast and reliable genetic diagnosis of OXPHOS patients.

PURPOSE: Oxidative phosphorylation is under dual genetic control of the nuclear and the mitochondrial DNA (mtDNA). Oxidative phosphorylation disorders are clinically and genetically heterogeneous, which makes it difficult to determine the genetic defect, and symptom-based protocols which link clinical symptoms directly to a specific gene or mtDNA mutation are falling short. Moreover, approximately 25% of the pediatric patients with oxidative phosphorylation disorders is estimated to have mutations in the mtDNA and a standard screening approach for common mutations and deletions will only explain part of these cases. Therefore, we tested a new CHIP-based screening method for the mtDNA. METHODS: MitoChip (Affymetrix) resequencing was performed on three test samples and on 28 patient samples. RESULTS: Call rates were 94% on average and heteroplasmy detection levels varied from 5-50%. A genetic diagnosis can be made in almost one-quarter of the patients at a potential output of 8 complete mtDNA sequences every 4 days. Moreover, a number of potentially pathogenic unclassified variants (UV) were detected. CONCLUSIONS: The availability of long-range PCR protocols and the predominance of single nucleotide substitutions in the mtDNA make the resequencing CHIP a very fast and reliable method to screen the complete mtDNA for mutations.

Child↗
PubMed2005

Increased expression of rapsyn in muscles prevents acetylcholine receptor loss in experimental autoimmune myasthenia gravis.

Myasthenia gravis is usually caused by autoantibodies to the acetylcholine receptor (AChR). The AChR is clustered and anchored in the postsynaptic membrane of the neuromuscular junction (NMJ) by a cytoplasmic protein called rapsyn. We previously showed that resistance to experimental autoimmune myasthenia gravis (EAMG) in aged rats correlates with increased rapsyn concentration at the NMJ. It is possible, therefore, that endogenous rapsyn expression may be an important determinant of AChR loss and neuromuscular transmission failure in the human disease, and that upregulation of rapsyn expression could be used therapeutically. To examine first a potential therapeutic application of rapsyn upregulation, we induced acute EAMG in young rats by passive transfer of AChR antibody, mAb 35, and used in vivo electroporation to over-express rapsyn unilaterally in one tibialis anterior. We looked at the compound muscle action potentials (CMAPs) in the tibialis anterior, at rapsyn and AChR expression by quantitative radioimmunoassay and immunofluorescence, and at the morphology of the NMJs, comparing the electroporated and untreated muscles, as well as the control and EAMG rats. In control rats, transfected muscle fibres had extrasynaptic rapsyn aggregates, as well as slightly increased rapsyn and AChR concentrations at the NMJ. In EAMG rats, despite deposits of the membrane attack complex, the rapsyn-overexpressing muscles showed no decrement in the CMAPs, no loss of AChR, and the majority had normal postsynaptic folds, whereas endplates of untreated muscles showed typical AChR loss and morphological damage. These data suggest not only that increasing rapsyn expression could be a potential treatment for selected muscles of myasthenia gravis patients, but also lend support to the hypothesis that individual differences in innate rapsyn expression could be a factor in determining disease severity.

Action Potentials↗
PubMed2005

Spastin mutations in sporadic adult-onset upper motor neuron syndromes.

Mutation of the spastin gene is the single most common cause of pure hereditary spastic paraparesis. In patients with an unexplained sporadic upper motor neuron (UMN) syndrome, clinical distinction between primary lateral sclerosis and sporadic hereditary spastic paraparesis may be problematic. To investigate whether spastin mutations are present in patients with primary lateral sclerosis and sporadic hereditary spastic paraparesis, we screened the spastin gene in 99 Dutch patients with an unexplained, apparently sporadic, adult-onset UMN syndrome. We found 6 mutations, of which 4 were novel, in the subgroup of 47 patients with UMN symptoms restricted to the legs (13%). Another novel spastin mutation was found in a patient with a rapidly progressive spinal and bulbar UMN syndrome that progressed to amyotrophic lateral sclerosis. In the patients with arm or bulbar UMN symptoms and slow progression, no spastin mutations were found. Our study shows that spastin mutations are a frequent cause of apparently sporadic spastic paraparesis but not of primary lateral sclerosis.

Adenosine Triphosphatases↗
PubMed2005

Severity of Guillain-Barré syndrome is associated with Fc gamma Receptor III polymorphisms.

Macrophages and ganglioside-specific IgG are involved in the pathogenesis of Guillain-Barre syndrome (GBS). Leukocyte IgG receptors (Fc gammaR) confer potent cellular effector functions to the specificity of IgG. The efficacy of IgG-mediated cellular inflammatory responses is determined by functional polymorphisms of three Fc gammaR subclasses (Fc gammaRIIa: H131/R131; Fc gammaRIIIa: V158/F158; Fc gammaRIIIb: NA1/NA2). Fc gammaR genotype distributions were determined in a Dutch, and British cohort of GBS patients and controls. In addition, a meta-analysis incorporating all previously published data, encompassing a total of 345 GBS patients and 714 healthy controls, was performed. Results suggest that Fc gammaRIII genotypes may represent mild disease-modifying factors in GBS.

Adult↗
PubMed2005

Multifocal motor neuropathy.

Multifocal motor neuropathy (MMN) is an immune-mediated disorder characterised by slowly progressive, asymmetrical weakness of limbs without sensory loss. The clinical presentation of MMN mimics that of lower-motor-neuron disease, but in nerve-conduction studies of patients with MMN motor-conduction block has been found. By contrast with chronic inflammatory demyelinating polyneuropathy, treatment with prednisolone and plasma exchange is generally ineffective in MMN and even associated with clinical worsening in some patients. Of the immunosuppressants, cyclophosphamide has been reported as effective but only anecdotally. Various open trials and four placebo-controlled trials have shown that treatment with high-dose intravenous immunoglobulin leads to improvement of muscle strength in patients with MMN. Although clinical, pathological, imaging, immunological, and electrophysiological studies have improved our understanding of MMN over the past 15 years, further research is needed to elucidate pathogenetic disease mechanisms in the disorder.

Clinical Trials as Topic↗
PubMed2005

Functional health status of patients with chronic inflammatory neuropathies.

The functioning of 12 patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and 18 patients with multifocal motor neuropathy (MMN) was evaluated to obtain health profiles and appropriate clinimetric instruments. Assessment was made in a cross-sectional study by means of a performance-based body function test (hand-held dynamometry), two performance-based activity tests (10-m walk test and Berg balance scale), a self-reported activity test (Canadian Occupational Performance Measure), and a self-reported functioning test (sickness impact profile 68). In both patient groups, CIDP and MMN, specific health profiles were manifest. A clear relationship between body function, activities, and functioning was not found. Therefore, to assess a patient with inflammatory neuropathy, it is recommended to assess body function as well as activities and functioning and to select appropriate clinimetric instruments specific for each type of neuropathy.

Adult↗
PubMed2004

Progressive idiopathic axonal neuropathy--a comparative clinical and histopathological study with vasculitic neuropathy.

Patients with a progressive disabling idiopathic axonal neuropathy could have a potentially treatable immune mediated neuropathy. To evaluate whether progressive idiopathic axonal neuropathy could be a pathologically difficult to prove vasculitic neuropathy pathologically difficult to prove or if it could be a separate clinical entity (i. e. with the axon as the primary immunological target), we performed a comparative clinical and histopathological study in 10 patients with progressive idiopathic axonal neuropathy, 10 patients with vasculitic neuropathy, and 12 patients with chronic idiopathic axonal polyneuropathy (CIAP). The clinical features and disease course in patients with progressive idiopathic axonal neuropathy and patients with vasculitic neuropathy were similar. Six patients with progressive idiopathic axonal neuropathy had been treated with prednisone and/or intravenous immunoglobulin. Disability decreased in all these six patients, but also in two of the four non-treated patients. Upon reviewing the sural nerve biopsy specimens, vasculitis was found in one patient with progressive idiopathic axonal neuropathy. Vasculitis-associated signs of ischemic injury or inflammation (most notably: large variation in fascicular axonal degeneration, perivascular inflammation, inflammation of the blood vessel wall without lumen obstruction) were found in four patients with progressive idiopathic axonal neuropathy, in all patients with vasculitic neuropathy, but were absent in patients with CIAP. The findings show that there is a small chance of finding sural nerve vasculitis upon scrutinising biopsy examination in progressive idiopathic axonal neuropathy. The presence of vasculitis-associated signs in progressive idiopathic axonal neuropathy suggests that some of these patients could have vasculitic neuropathy, even if vasculitic lesions cannot be demonstrated. However, if inflammatory changes cannot be demonstrated this does not preclude an immune-mediated origin.

Adolescent↗
PubMed2004

The future of motor neuron disease: the challenge is in the genes.

Adult-onset motor neuron disease (MND) includes sporadic and familial forms of amyotrophic lateral sclerosis (ALS), lower motor neuron disease including progressive and segmental spinal muscular atrophy (LMND) and primary lateral sclerosis (PLS). ALS/MND can be considered to be a spectrum of neurodegenerative diseases characterised by a preferential degeneration of upper and/or lower motor neurons. ALS and LMND have a complex multifactorial aetiology and a large clinical variability. This combination warrants an increasing genomics approach in future research. Genomics is the structural and functional study of genomes--i. e. the complete set of chromosomes and the genes they contain. Several methods may help to understand gene functions, and every method has led to its own "omics". The study of the complex relationship between on the one hand genomics data, transcriptomics data, proteomics data, and interactomics data and on the other hand the phenotype, is called "phenomics". In phenomics, the extensive and detailed phenotyping by the clinician is a prerequisite for meaningful associations. As a consequence, in ALS/MND clinicians have the task to agree about different clinical subtypes in order to make these associations and hence to gain further insight into the complex pathogenesis and identification of diagnostic markers in ALS/MND. Also, several new approaches in the treatment of ALS/MND are here discussed, including the viral delivery of protective compounds, RNA-interference, and stem cell therapy. Further, we argue that a future challenge is to allow for patients to have early access to multidisciplinary centres with specialist knowledge of ALS/MND. These centres can apply specific models of care for people with ALS/MND, but must be designed in a patient-centred format. Ultimately, these models should be assessed according to their outcomes.

Forecasting↗
PubMed2004

CGP 3466B has no effect on disease course of (G93A) mSOD1 transgenic mice.

BACKGROUND: There is an accumulating body of evidence that apoptosis is involved in the motor neuron death that occurs in ALS, and in the (G93A) mSOD1 transgenic mouse model (mSOD1 mice). CGP 3466B, a tricyclic propargylamine structurally related to (-)-deprenyl, was found to inhibit apoptosis in a wide variety of in vitro and in vivo models. We therefore studied the effect of CGP 3466B in mSOD1 mice. METHODS: As the effect of CGP 3466B was previously reported to have a bell-shaped curve, we performed a dose-ranging study. High-copy G93A mSOD1 mice were treated subcutaneously from the age of 50 days until death with four concentrations of CGP 3466B (0.39 microg kg(-1), 3.9 microg kg(-1), 39 microg kg(-1), and 390 microg kg(-1)). Behavioural tests were performed daily to determine disease onset, disease progression and survival. At the age of 110 days, two mice per group were sacrificed for histopathological analysis of the lumbar ventral horn and for semiquantitative analysis of motor neuron number. RESULTS: We observed no effect on disease onset, disease progression, or survival of the mice. We also did not observe a significant effect on the number of motor neurons due to CGP 3466B. CONCLUSIONS: We conclude that in high-copy G93A mSOD1 mice, chronic subcutaneous treatment with CGP 3466B offers no clinical benefit.

Amyotrophic Lateral Sclerosis↗
PubMed2004

Sequential designs for clinical trials in amyotrophic lateral sclerosis.

BACKGROUND: The objective of this paper is to discuss the sequential trial design and its advantages in clinical trials for ALS. The sequential trial design is an alternative to the classical trial design, which permits stopping a study as soon as a treatment effect can be significantly demonstrated or denied. METHODS: As an example of a sequential survival analysis, a recently completed clinical trial is described. A secondary outcome measure used in the same trial, the decline of the vital lung capacity, was re-analyzed sequentially, in order to illustrate the use of the sequential method for a non-survival variable. To compare the classical with the sequential trial design, the number of patients needed in trials aiming at survival effects ranging from 10% to 20% with a power of 80% or 90% was calculated for both designs. RESULTS: In the given examples the time needed to prove the null hypothesis in the survival analysis, and the number of patients needed to prove the null hypothesis in the analysis of the vital capacity is lower than would have been the case in a classical analysis. In 18 of 24 different situations, the chance is at least 90% that with a sequential trial design fewer patients are needed. CONCLUSIONS: We argue that, particularly for ALS trials, a sequential design may be superior to a classical trial design, as it most often requires fewer patients than classically designed trials of equal power, and more importantly may avoid unnecessary continuation.

Amyotrophic Lateral Sclerosis↗
PubMed2003

Disease course of Charcot-Marie-Tooth disease type 2: a 5-year follow-up study.

BACKGROUND: Charcot-Marie-Tooth disease (CMT) type 2 is the axonal variant of an inherited, sensorimotor polyneuropathy. To our knowledge, the clinical course of CMT type 2 has never been prospectively studied in a large group of patients. OBJECTIVE: To prospectively evaluate the disease course of patients with CMT type 2. METHODS: We prospectively evaluated the disease course in patients with CMT type 2. Forty-three patients (24 men) of 27 families with CMT type 2 were included. All patients were analyzed by the same investigator at entry and after 5 years. The standardized protocol included manual muscle testing, which could lead to a motor sum score of 140 points, and quantification of sensory deficit. Disability was assessed using the modified Rankin scale, and quality of life was assessed using the RAND 36-item health survey questionnaire. Eighteen families were tested for known mutations in the MPZ, PMP22, and GJB1 genes. RESULTS: At entry, the mean +/- SD age of the patients was 52 +/- 14 years, and the mean +/- SD duration of disease was 12 +/- 8 years. The median motor sum score deteriorated from 135 to 128 points (P =.02). Progression was never rapid. There was no sensory deterioration. The Rankin score decreased by 1 point in 16 patients. At follow-up, more patients needed walking aids, but most patients remained ambulant. The number of patients with claw toes increased, whereas the number of patients with foot deformities such as pes cavus and short calf muscles remained stable. There was no correlation between deterioration and age. Analysis of quality of life did not show any changes. In one family, a mutation in the GJB1 gene was found. CONCLUSION: This prospective study shows a slow deterioration of muscle strength and increase in disability in CMT type 2 during a 5-year follow-up period.

Adult↗