PubMed Health⌕ Search

Biomedical subjects

D Hilton-Jones

Publications and source records attributed to D Hilton-Jones.

At least 19 recordsLinked to original sources
PubMed2006

Guidelines for the treatment of autoimmune neuromuscular transmission disorders.

Important progress has been made in our understanding of the cellular and molecular processes underlying the autoimmune neuromuscular transmission (NMT) disorders; myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS) and neuromyotonia (peripheral nerve hyperexcitability; Isaacs syndrome). To prepare consensus guidelines for the treatment of the autoimmune NMT disorders. References retrieved from MEDLINE, EMBASE and the Cochrane Library were considered and statements prepared and agreed on by disease experts and a patient representative. The proposed practical treatment guidelines are agreed upon by the Task Force: (i) Anticholinesterase drugs should be the first drug to be given in the management of MG (good practice point). (ii) Plasma exchange is recommended as a short-term treatment in MG, especially in severe cases to induce remission and in preparation for surgery (level B recommendation). (iii) Intravenous immunoglobulin (IvIg) and plasma exchange are equally effective for the treatment of MG exacerbations (level A Recommendation). (iv) For patients with non-thymomatous autoimmune MG, thymectomy (TE) is recommended as an option to increase the probability of remission or improvement (level B recommendation). (v) Once thymoma is diagnosed TE is indicated irrespective of the severity of MG (level A recommendation). (vi) Oral corticosteroids is a first choice drug when immunosuppressive drugs are necessary in MG (good practice point). (vii) In patients where long-term immunosuppression is necessary, azathioprine is recommended together with steroids to allow tapering the steroids to the lowest possible dose whilst maintaining azathioprine (level A recommendation). (viii) 3,4-diaminopyridine is recommended as symptomatic treatment and IvIg has a positive short-term effect in LEMS (good practice point). (ix) All neuromyotonia patients should be treated symptomatically with an anti-epileptic drug that reduces peripheral nerve hyperexcitability (good practice point). (x) Definitive management of paraneoplastic neuromyotonia and LEMS is treatment of the underlying tumour (good practice point). (xi) For immunosuppressive treatment of LEMS and NMT it is reasonable to adopt treatment procedures by analogy with MG (good practice point).

Adrenal Cortex Hormones↗
PubMed2006

Myotonic dystrophy: practical issues relating to assessment of strength.

BACKGROUND: Myotonic dystrophy type 1 is a slowly progressive multisystem disease in which skeletal muscle involvement is prominent. As novel physical and pharmacological treatments become available, it is crucial to be able to measure their efficacy accurately. METHODS: 158 consecutive patients with myotonic dystrophy were assessed annually in a specialist muscle clinic. Strength was measured using both the Medical Research Council (MRC) scale and a hand-held dynamometer. Dynamometer readings were obtained from 108 normal subjects (controls). RESULTS: The movements showing the greatest rate of change in strength were ankle dorsiflexion and pinch grip. Both of these showed a decline of only 0.06 points/year on the MRC scale. Using a hand-held dynamometer, a change in strength of 1.18 kgN/year for women and 1.61 kgN/year for men was detected. CONCLUSIONS: The MRC scale is unsuitable for detecting the small changes in strength seen in a slowly progressive disease such as myotonic dystrophy. Dynamometry provides a simple alternative that can give meaningful data over the duration of a typical clinical trial.

Adult↗
PubMed2005

Andersen-Tawil syndrome: new potassium channel mutations and possible phenotypic variation.

OBJECTIVE: To evaluate clinical, genetic, and electrophysiologic features of patients with Andersen-Tawil syndrome (ATS) in the United Kingdom. METHODS: Clinical and neurophysiologic evaluation was conducted of 11 families suspected to have ATS. Molecular genetic analysis of each proband was performed by direct DNA sequencing of the entire coding region of KCNJ2. Control samples were screened by direct DNA sequencing. The electrophysiologic consequences of several new mutations were studied in an oocyte expression system. RESULTS: All 11 ATS families harbored pathogenic mutations in KCNJ2 with six mutations not previously reported. Some unusual clinical features including renal tubular defect, CNS involvement, and dental and phonation abnormalities were observed. Five mutations (T75M, D78G, R82Q, L217P, and G300D) were expressed, all of which resulted in nonfunctional channels when expressed alone, and co-expression with wild-type (WT) KCNJ2 demonstrated a dominant negative effect. CONCLUSION: Six new disease-causing mutations in KCNJ2 were identified, one of which was in a PIP2 binding site. Molecular expression studies indicated that five of the mutations exerted a dominant negative effect on the wild-type allele. KCNJ2 mutations are an important cause of ATS in the UK.

Adolescent↗
PubMed2003

Rapsyn mutations in hereditary myasthenia: distinct early- and late-onset phenotypes.

Rapsyn mutations in 16 unrelated patients with a congenital/hereditary myasthenic syndrome were identified, and a mutation (N88K) common to each of them was found. Two distinct phenotypes were noted: early and late onset. The former is frequently associated with arthrogryposis multiplex congenita and life-threatening crises. The late-onset phenotype developed in adolescence or adulthood and was initially mistaken for seronegative myasthenia gravis. Recognition of this late-onset phenotype should prevent inappropriate immunotherapy.

Adolescent↗
PubMed2003

Reduction in excess daytime sleepiness by modafinil in patients with myotonic dystrophy.

Patients with myotonic dystrophy frequently suffer from excess daytime sleepiness, which can be a significant cause of disability. Previous studies have indicated that this excess daytime sleepiness is only occasionally due to obstructive sleep apnoea and may be principally of central nervous system origin. Modafinil has been successfully used to treat narcolepsy, a central disorder causing excess daytime sleepiness. We have investigated the use of this drug in myotonic dystrophy patients with excess daytime sleepiness. Patients were recruited from a clinic population on the basis of screening with the Epworth Sleepiness Scale. Patients scoring 10 and above were invited to participate in a randomized double-blind crossover trial of modafinil versus placebo, with four weeks in each arm of the study separated by a 2-week washout period. Patients were assessed by polysomnography at baseline. The primary outcome measures were change in both the Epworth Sleepiness Scale and a modified Maintenance of Wakefulness Test, which were measured at the start of each arm of the trial and in week 3 of each intervention period. In agreement with previous smaller studies, sleepiness is not correlated with CTG expansion size. Treatment with modafinil showed a non-significant reduction in median Epworth Sleepiness Scale. However, the median Maintenance of Wakefulness Test score was prolonged by treatment (31.7-40 min, P=0.006). There were no significant adverse cardiac effects of the drug in this group of patients (resting 12 lead and 24 h ECG monitoring). Selected patients with myotonic dystrophy and excess daytime sleepiness may benefit from modafinil. In this patient group the Epworth Sleepiness Scale may not be the most reliable measure of sleepiness. Despite the potential for cardiac disease in these patients, the drug was well tolerated with no adverse effects.

Adult↗
PubMed2003

Three cases of androgen-dependent disease associated with myotonic dystrophy.

Three cases of androgen-dependent disease in females with myotonic dystrophy are described. Serum androgens in individuals affected by myotonic dystrophy are known to be lower on average than in normal controls. Despite this these three females developed diseases that are androgen dependent, including acne, hidradenitis suppurativa, androgenetic alopecia and keratosis pilaris. These cases support the hypothesis that the peripheral response to androgens rather than absolute circulating levels of androgens is important in androgen-dependent conditions.

Acne Vulgaris↗
PubMed2002

An expanded cortical representation for hand movement after peripheral motor denervation.

OBJECTIVES: Functional reorganisation of the motor or sensory cortex has been demonstrated in animals after section of mixed peripheral nerves. Here functional changes in the motor cortex specifically after peripheral motor denervation in humans are investigated. METHODS: Functional MRI (fMRI) was used to study brain activation during a finger flexion-extension task in patients with a late onset, acquired pure motor neuropathy (n=6), contrasting results with those from patients with pure sensory neuropathies (n=4) or healthy controls (n=7). RESULTS: Increases in the extent of activation in the motor cortex both ipsilateral and contralateral to the hand moved were found in the patients with motor neuropathy. The neuroanatomical localisation of the mixed contralateral sensorimotor cortex activation volume was more posterior for the patients with motor neuropathy than for the healthy controls (mean difference, 12 mm, p<0.05). The pure sensory neuropathy group by contrast showed no change in the extent of activation relative to healthy controls and a trend for more anterior primary sensorimotor cortex activation (p<0.06). To test whether the increased activation volumes found in patients with motor neuropathy were a result simply of factors such as increased effort with movement rather than the motor denervation, patients with hand weakness from inclusion body myositis (n=4) were studied while making similar hand movements. No differences in either the numbers of significantly activated voxels or in their localisation were found relative to healthy controls (n=10). CONCLUSIONS: These results provide a novel demonstration that peripheral denervation (as distinguished from factors related to weakness) leads to functional reorganisation of the sensorimotor cortex in the adult brain. This suggests that adaptive responses to motor denervation involve the central as well as the peripheral nervous system.

Adult↗
PubMed2002

Six novel connexin32 (GJB1) mutations in X-linked Charcot-Marie-Tooth disease.

X-linked Charcot-Marie-Tooth disease (CMTX) is a clinically heterogeneous hereditary motor and sensory neuropathy with X-linked transmission. Common clinical manifestations of CMTX, as in other forms of Charcot-Marie-Tooth disease (CMT), are distal muscle wasting and weakness, hyporeflexia, distal sensory disturbance, and foot deformities. Motor nerve conduction velocity is reduced. In male patients it is often less than 38 m/s in the median nerve (a value often used to distinguish between "demyelinating" and "axonal" forms of CMT), but in female patients conduction velocity may be faster than this or normal. Mutations in the connexin32 (gap junction protein beta 1 (GJB1)) gene are responsible for the majority of CMTX cases. This report describes six British CMTX families with six novel mutations (four missense, one nonsense, and one frame shift) of the GJB1 gene. Affected members in these six families had typical signs of CMT but in some affected members of three families there was additional central nervous system involvement or deafness in the absence of any other explanation other than CMT.

Adolescent↗
PubMed2001

Cardiac abnormalities and skeletal muscle weakness in carriers of Duchenne and Becker muscular dystrophies and controls.

Cardiac abnormalities, cardiomyopathy and skeletal muscle weakness have been described in female carriers of the Xp21 (Duchenne and Becker) muscular dystrophies (J Neurol 1975;209(4):279-285; Br Med J 1969;2:418-420; J AmMed Assoc 1996;275(17):1335-1338; Neurology 1980;30(5):497-501; Neuromusc Disord 1999;9:347-351; Arch Neurol 1989;46:673-675). We have screened volunteers from our Xp21 genetics register and found the prevalence of previously unrecognized, clinically relevant, abnormalities in this group to be less than previously reported. We studied 91 women (56 carriers and 35 controls), aged between 18 and 69 years, from our local population known to the Oxford Regional Genetics Register. Our study included controls, with the investigators being blind to the subject's genetic status. The prevalence of previously unrecognised cardiac abnormalities on echocardiogram and ECG was 18% (10/56). Seven percent (4/56) of carriers had cardiomyopathy, defined by significant LV dilatation and decreased shortening fraction. In most cases, subjects with abnormal cardiac findings were asymptomatic. Echocardiography was more frequently abnormal than electrocardiography, but in many subjects the measurements of left ventricular dimensions were only just outside the normal ranges. The prevalence of skeletal muscle weakness was 12% (7/56). It was usually recognized by the individual, although not previously volunteered, but was mild and did not substantially affect activities of daily living.

Adult↗
PubMed2001

Oculopharyngeal muscular dystrophy: phenotypic and genotypic studies in a UK population.

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disorder of late onset that commonly presents with ptosis and dysphagia. The genetic basis of the condition has been identified recently as a stable trinucleotide repeat expansion in exon 1 of the poly(A) binding protein 2 gene (PABP2), in which (GCG)(6) is the normal repeat length. The prevalence of OPMD is greatest in patients of French-Canadian origin. It is not clear if expansion repeat length is a reliable test in other populations. In this study, we analysed the phenotypic and genotypic characteristics of 31 patients with OPMD in the UK. Ptosis was the first reported symptom in two-thirds of the patients, and half of the subjects studied had evidence of ophthalmoplegia. All but one family had a pathological expansion in the PABP2 gene, ranging from (GCG)(8) to (GCG)(13). In contrast to the French-Canadian population, (GCG)(10) was almost as common as (GCG)(9), evidence against a strong founder effect in the UK population. There was a weak association between repeat length and age of disease onset. Patients with longer repeat lengths, such as (GCG)(13), developed severe limb weakness early in the disease. We were unable to detect the (GCG)(7) polymorphism in over 200 normal controls, suggesting that the frequency of this expansion is lower than that found in the French-Canadian population. One family was negative for the expansion. Affected members presented with the classical features of OPMD, namely ptosis, dysphagia and cytoplasmic inclusions on muscle biopsy, although with some atypical features, such as early age of onset, high serum levels of creatine kinase and a profound ophthalmoplegia. This family is an example of a GCG expansion-negative oculopharyngeal syndrome requiring further genetic investigation. We conclude that PABP2 analysis is a reliable non-invasive diagnostic test for OPMD in the UK population.

Adolescent↗
PubMed2001

Inflammatory muscle diseases.

Dermatomyositis and polymyositis are treatable disorders of skeletal muscle. Despite their clinical similarities, they appear to have fundamentally different autoimmune origins. Inclusion body myositis, from its origins 30 years ago, has emerged as the commonest acquired myopathy of the elderly. Despite inflammatory changes, it is unclear whether it should be considered a primary inflammatory myopathy, and it generally responds poorly to the same treatments that are effective in other inflammatory myopathies.

Dermatomyositis↗
PubMed2001

Does cytosine-thymine-guanine (CTG) expansion size predict cardiac events and electrocardiographic progression in myotonic dystrophy?

OBJECTIVE: To assess whether the size of the cytosine-thymine-guanine (CTG) expansion mutation in myotonic dystrophy predicts progression of conduction system disease and cardiac events. DESIGN: Longitudinal study involving ECG and clinical follow up over (mean (SD)) 4.8 (1.8) and 6.2 (1.9) years, respectively, of patients stratified by CTG expansion size (E0 to E4). PATIENTS: 73 adult patients under annual review in a regional myotonic dystrophy clinic. Patients were grouped into E0/E1 (n = 25), E2 (n = 34), and E3/E4 (n = 14). RESULTS: The proportion of patients with a QRS complex > 100 ms at baseline increased with the size of the CTG expansion (EO/E1, 4%; E2, 12%; E3/E4, 36%; p = 0.02). This trend was more pronounced at follow up (E0/E1, 4%; E2, 21%; E3/E4, 57%; p = 0.0004). The rate of widening of the QRS complex (ms/year) was similarly related to the size of the mutation (EO/E1, 0.4 (1.3); E2, 1.4 (2.5); E3/E4, 1.5 (1.6); p = 0.04). First degree atrioventricular block was present in 23% of patients at baseline and 34% at follow up, with no significant relation to expansion size. Seven patients suffered a cardiac event during follow up (sudden death in two, permanent pacemaker insertion in three, chronic atrial arrhythmia in two), of whom six were in CTG expansion group E2 or greater. Patients who experienced a cardiac event during follow up had more rapid rates of PR interval increase (9.9 (11.1) v 1.6 (2.9) ms/year; p = 0.008) and a trend to greater QRS complex widening (3.6 (4.5) v 0.9 (1.5) ms/year; p = 0.06) than those who did not. CONCLUSIONS: Larger CTG expansions are associated with a higher rate of conduction disease progression and a trend to increased risk of cardiac events in myotonic dystrophy.

Adult↗
PubMed2000

Magnetic resonance spectroscopy evidence of abnormal cardiac energetics in Xp21 muscular dystrophy.

OBJECTIVES: Our aim was to measure the cardiac phosphocreatine to adenosine triphosphate ratio (PCr/ATP) noninvasively in patients and carriers of Xp21 muscular dystrophy and to correlate the results with left ventricular (LV) function as measured by echocardiography. BACKGROUND: Duchenne and Becker muscular dystrophy (the Xp21 dystrophies) are associated with the absence or altered expression of dystrophin in cardiac and skeletal muscles. They are frequently complicated by cardiac hypertrophy and dilated cardiomyopathy. The main role of dystrophin is believed to be structural, but it may also be involved in signaling processes. Defects in energy metabolism have been found in skeletal muscle in patients with Xp21 muscular dystrophy. We therefore hypothesized that a defect in energy metabolism may be part of the mechanism leading to the cardiomyopathy of Xp21 muscular dystrophy. METHODS: Thirteen men with Becker muscular dystrophy, 10 female carriers and 23 control subjects were studied using phosphorus-31 magnetic resonance spectroscopy and echocardiography. RESULTS: The PCr/ATP was significantly reduced in patients (1.55+/-0.37) and carriers (1.37+/-0.25) as compared with control subjects (2.44+/-0.33; p<0.0001 for both groups). The PCr/ATP did not correlate with LV ejection fraction or mass index. CONCLUSIONS: Altered expression of dystrophin leads to a reduction in the PCr/ATP. Since this reduction did not correlate with indexes of left ventricular function, this raises the possibility of a direct link between altered dystrophin expression and the development of cardiomyopathy in such patients.

Adenosine Triphosphate↗
PubMed1998

Normal in vivo skeletal muscle oxidative metabolism in sporadic inclusion body myositis assessed by 31P-magnetic resonance spectroscopy.

Sporadic inclusion body myositis (s-IBM) is a chronic inflammatory myopathy of unknown pathogenesis. The common findings of ragged red fibres, cytochrome c oxidase-negative fibres and multiple mitochondrial DNA deletions in the muscle of patients with s-IBM have suggested that a deficit of energy metabolism may be of pathogenic relevance. To test this hypothesis we used 31P magnetic resonance spectroscopy to assess in vivo skeletal muscle mitochondrial function in the calf muscles of 12 patients with definite s-IBM. Eleven patients showed multiple mitochondrial DNA deletions in skeletal muscle and 67% showed ragged red fibres and/or cytochrome c oxidase-negative fibres. T1-weighted MR images showed increased signal intensity in the calf muscle of all patients except one. The involvement of calf muscle was confirmed by 31P magnetic resonance spectroscopy of resting muscle, which disclosed abnormalities in metabolite ratios in all patients. However, muscle oxidative metabolism assessed during recovery from exercise was normal in patients with s-IBM, as maximum rates of mitochondrial ATP production and post-exercise ADP recovery rates were within the normal range in all cases. We conclude that muscle mitochondrial abnormalities are a secondary process and unlikely to play a significant role in the pathogenesis of s-IBM.

Adenosine Diphosphate↗
PubMed1998

Del(18p) shown to be a cryptic translocation using a multiprobe FISH assay for subtelomeric chromosome rearrangements.

We have previously described a fluorescence in situ hybridisation (FISH) assay for the simultaneous analysis of all human subtelomeric regions using a single microscope slide. Here we report the use of this multiprobe FISH assay in the study of a patient whose karyotype was reported by G banding analysis as 46,XX,del(18)(p11.2). Although the proband had some features suggestive of a chromosomal abnormality, relatively few of the specific features of del(18p) were present. She was a 37 year old female with mild distal spinal muscular atrophy (SMA), arthritis of the hands, an abnormal chest shape (pectus excavatum), and an unusual skin condition (keratosis pilaris). Reverse chromosome painting with degenerate oligonucleotide primer-polymerase chain reaction (DOP-PCR) amplified del(18p) chromosomes as a probe confirmed the abnormality as del(18p), with no evidence of any other chromosome involvement. Subsequently, the multiprobe FISH assay confirmed deletion of 18p subtelomeric sequence. However, the assay also showed that sequences corresponding to the 2p subtelomeric probe were present on the tip of the shortened 18p. The patient is therefore monosomic for 18p11.2-pter and trisomic for 2p25-pter, and the revised karyotype is 46,XX,der(18)t(2;18)(p25; p11.2). We believe that a proportion of all cases reported as telomeric deletions may be cryptic translocations involving other chromosome subtelomeric regions. Further studies such as this are necessary to define accurately the clinical characteristics associated with pure monosomy in chromosomal deletion syndromes.

Adult↗
PubMed1997

Dystrobrevin deficiency at the sarcolemma of patients with muscular dystrophy.

Mutations in the genes encoding dystrophin or dystrophin-associated proteins are responsible for Duchenne muscular dystrophy or various forms of limb-girdle muscular dystrophies respectively. We have recently cloned the gene for the murine 87 kDa postsynaptic protein dystrobrevin, a dystrophin-associated protein. Anti-dystrobrevin antibodies stain the sarcolemma in normal skeletal muscle indicating that dystrobrevin co-localises with dystrophin and the dystrophin-associated protein complex. By contrast, dystrobrevin membrane staining is severely reduced in muscles of Duchenne muscular dystrophy patients, consistent with dystrobrevin being a dystrophin-associated protein. Interestingly, dystrobrevin staining at the sarcolemma is dramatically reduced in patients with limb-girdle muscular dystrophy arising from the loss of one or all of the sarcoglycan components. Normal dystrobrevin staining is observed in patients with other forms of limb-girdle muscular dystrophy where dystrophin and the rest of the dystrophin-associated protein complex are normally expressed and in other neuromuscular disorders. Our results show that dystrobrevin-deficiency is a generic feature of dystrophies linked to dystrophin and the dystrophin-associated proteins. This is the first indication that a cytoplasmic component of the dystrophin-associated protein complex may be involved in the pathogenesis of limb-girdle muscular dystrophy.

Cytoskeletal Proteins↗