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A J Thompson

Publications and source records attributed to A J Thompson.

At least 19 recordsLinked to original sources
PubMed2000

A retrospective analysis of outcome in severe Guillain-Barre syndrome following combined neurological and rehabilitation management.

PURPOSE: To determine the outcome in severe Guillain-Barre syndrome following combined neurological and rehabilitation management using standardized disability and handicap measures and to identify the factors which affect this outcome. METHODS: A retrospective study was performed of 24 patients with Guillain-Barre Syndrome admitted over a 3 year period to the neurological rehabilitation unit of the National Hospital for Neurology and Neurosurgery. Queen Square, London. Disability and handicap on admission and discharge were measured using the modified Barthel Index (BI), Functional Independence Measure (FIM). Environmental Status Scale (ESS) and Handicap Assessment Scale (HAS). Data was collected to identify any factors affecting outcome; age at onset, time to nadir, duration of ventilation, total in-patient stay, duration of stay at the neurological rehabilitation unit, symptoms, signs and electrophysiological findings. RESULTS: The majority of patients had multiple problems. Outcome was related to the duration of rehabilitation. The mean modified BI score and the FIM score increased whereas ESS scores and HAS scores decreased, these changes were compatible with a reduction in disability and handicap. CONCLUSIONS: Significant improvement in function occurred during rehabilitation. These changes can be demonstrated using standardized outcome measures.

Adult↗
PubMed2000

Progressive cerebral atrophy in MS: a serial study using registered, volumetric MRI.

OBJECTIVE: To assess the potential of registered volumetric MRI in measuring rates of atrophy in MS. BACKGROUND: Pathologic and imaging studies suggest that the development of permanent neurologic impairment in MS is associated with progressive brain and spinal cord atrophy. Atrophy has been suggested as a potential marker of disease progression. Conventional atrophy measurements requiring manual outlining are time-consuming and subject to reproducibility problems. Registration of serial MRI may offer a useful alternative in that cerebral losses may be measured directly from automated subtraction of brain volumes. METHODS: Twenty-six patients with MS and 26 age- and gender-matched controls had two volumetric brain MR studies 1 year apart. Baseline brain and ventricular volumes were measured using semiautomated techniques, and follow-up scans were registered to baseline. Rates of cerebral atrophy were calculated directly from the registered scans. RESULTS: Baseline brain volumes in the MS group were smaller (mean difference 78 mL [95% CI 13 to 143; p = 0.02]) and ventricular volumes greater (mean difference 12 mL [95% CI 6 to 18; p < 0.001]) than controls. The rate of cerebral atrophy in the MS group (0.8% per year) was over twice that of controls (0.3%), and the rate of ventricular enlargement was five times greater than the controls (1.6 versus 0.3 mL/year). CONCLUSION: Progressive cerebral atrophy is an important feature of MS. Registration-based measurements are sensitive and reproducible, allowing progressive atrophy to be detected within 1 year and may have potential as a marker of progression in monitoring therapeutic trials.

Adult↗
PubMed2000

A comparison of neuropsychological deficits in primary and secondary progressive multiple sclerosis.

Neuropsychological deficits and the relationship to brain pathology were examined in 13 primary progressive (PP) and 12 secondary progressive (SP) multiple sclerosis patients with a similar duration of the progressive phase and comparable physical disability. A battery of neuropsychological tests to assess attention, short-term and working memory was administered to the patients, and their performance was compared to that of 20 healthy controls matched for age and premorbid IQ. Total cerebral lesion load on T2-weighted magnetic resonance imaging was measured in the patients. Both PP and SP patients performed significantly worse than controls in most of the neuropsychological tests. There were only subtle differences between SP and PP on the working memory task although magnetic resonance imaging lesion load was significantly higher in SP than in PP patients. In this exploratory study only subtle differences in cognitive impairment were detected between SP and PP patients matched for physical disability and relevant illness features. The results also suggest that the severity of cognitive impairment cannot be fully explained by the extent of abnormalities detected on conventional T2-weighted magnetic resonance images, and that other pathological abnormalities such as in normal-appearing white matter are likely to be involved.

Adult↗
PubMed2000

Relation of impairment to everyday competence in visual disorientation syndrome: evidence from a single case study.

OBJECTIVE: To determine the relation of neurology and neuropsychology to everyday competence. DESIGN: The association of these three domains was investigated using a single case multiple baseline design with two phases. Phase A comprised 6 weeks that coincided with an inpatient admission. Phase B comprised 3 months spent at home. A battery of visual spatial tests was completed every fortnight during the A phase and at the end of the B phase. Two new tests of relevant neurologic function with control data were developed and used weekly during the A phase and at the end of the B phase. The first test recorded the speed, accuracy, and efficiency of her walking, and the second test recorded her depth perception. SETTING: Tertiary care center. PARTICIPANT: A 35-year-old woman who suffered a venous sinus thrombosis with visual disorientation syndrome. RESULTS: During Phase A, she achieved significant functional gains in mobility, dressing, bathing, and domestic tasks, in the context of unchanging psychometric test scores and static relevant neurologic function. During Phase B, she achieved few functional gains, despite improvements in neurologic status, demonstrated by depth perception. CONCLUSIONS: Everyday function can progress without improvement in neurologic and cognitive status.

Activities of Daily Living↗
PubMed2000

A (1)H magnetic resonance spectroscopy study of aging in parietal white matter: implications for trials in multiple sclerosis.

1H magnetic resonance spectroscopy (MRS) provides a unique tool to detect and quantify brain metabolites. In multiple sclerosis it can be used to investigate axonal loss or dysfunction through measurement of N-acetyl aspartate (NAA), a neuronal marker. Previous studies in adults have reported variable effects of aging on metabolite concentrations but have predominantly focused on changes in the elderly. This study has examined a younger adult age group to provide a reference database more applicable to the multiple sclerosis population. Single voxel (1)H MRS was carried out in 44 subjects between 22 and 62 years of age. Sixteen subjects underwent repeat examination after one year. Absolute concentrations of NA (the sum of NAA and N-acetyl aspartate glutamate), NAA, creatine/phosphocreatine (Cr), choline containing compounds (Cho) and myo-inositol (mI) were measured. NA, NAA and mI concentrations did not correlate with age but there were significant correlations between age and Cr (r = 0.43, p = 0.004) and Cho (r = 0.38, p = 0. 011) concentrations. No significant differences in metabolite concentrations were seen over one year. This study provides evidence that age-related changes of metabolite concentrations occur even in a young to middle aged adult population. This emphasizes the need to perform absolute quantification of metabolite concentrations rather than ratios and the importance of age-matching in (1)H MRS studies of multiple sclerosis.

Adolescent↗
PubMed2000

Abscisic acid biosynthesis in tomato: regulation of zeaxanthin epoxidase and 9-cis-epoxycarotenoid dioxygenase mRNAs by light/dark cycles, water stress and abscisic acid.

Two genes encoding enzymes in the abscisic acid (ABA) biosynthesis pathway, zeaxanthin epoxidase (ZEP) and 9-cis-epoxycarotenoid dioxygenase (NCED), have previously been cloned by transposon tagging in Nicotiana plumbaginifolia and maize respectively. We demonstrate that antisense down-regulation of the tomato gene LeZEP1 causes accumulation of zeaxanthin in leaves, suggesting that this gene also encodes ZEP. LeNCED1 is known to encode NCED from characterization of a null mutation (notabilis) in tomato. We have used LeZEP1 and LeNCED1 as probes to study gene expression in leaves and roots of whole plants given drought treatments, during light/dark cycles, and during dehydration of detached leaves. During drought stress, NCED mRNA increased in both leaves and roots, whereas ZEP mRNA increased in roots but not leaves. When detached leaves were dehydrated, NCED mRNA responded rapidly to small reductions in water content. Using a detached leaf system with ABA-deficient mutants and ABA feeding, we investigated the possibility that NCED mRNA is regulated by the end product of the pathway, ABA, but found no evidence that this is the case. We also describe strong diurnal expression patterns for both ZEP and NCED, with the two genes displaying distinctly different patterns. ZEP mRNA oscillated with a phase very similar to light-harvesting complex II (LHCII) mRNA, and oscillations continued in a 48 h dark period. NCED mRNA oscillated with a different phase and remained low during a 48 h dark period. Implications for regulation of water stress-induced ABA biosynthesis are discussed.

Abscisic Acid↗
PubMed2000

Ectopic expression of a tomato 9-cis-epoxycarotenoid dioxygenase gene causes over-production of abscisic acid.

The tomato mutant notabilis has a wilty phenotype as a result of abscisic acid (ABA) deficiency. The wild-type allele of notabilis, LeNCED1, encodes a putative 9-cis-epoxycarotenoid dioxygenase (NCED) with a potential regulatory role in ABA biosynthesis. We have created transgenic tobacco plants in which expression of the LeNCED1 coding region is under tetracycline-inducible control. When leaf explants from these plants were treated with tetracycline, NCED mRNA was induced and bulk leaf ABA content increased by up to 10-fold. Transgenic tomato plants were also produced containing the LeNCED1 coding region under the control of one of two strong constitutive promoters, either the doubly enhanced CaMV 35S promoter or the chimaeric 'Super-Promoter'. Many of these plants were wilty, suggesting co-suppression of endogenous gene activity; however three transformants displayed a common, heritable phenotype that could be due to enhanced ABA biosynthesis, showing increased guttation and seed dormancy. Progeny from two of these transformants were further characterized, and it was shown that they also exhibited reduced stomatal conductance, increased NCED mRNA and elevated seed ABA content. Progeny of one transformant had significantly higher bulk leaf ABA content compared to the wild type. The increased seed dormancy was reversed by addition of the carotenoid biosynthesis inhibitor norflurazon. These data provide strong evidence that NCED is indeed a key regulatory enzyme in ABA biosynthesis in leaves, and demonstrate for the first time that plant ABA content can be increased through manipulating NCED.

Abscisic Acid↗
PubMed2000

The pathogenesis of lesions and normal-appearing white matter changes in multiple sclerosis: a serial diffusion MRI study.

The idea that the initiating event in the formation of all new multiple sclerosis lesions is a focal blood-brain barrier (BBB) leakage associated with perivascular inflammation has been challenged recently by the observation of subtle abnormalities in some quantitative magnetic resonance (MR) parameters (including the magnetization transfer ratio) prior to lesion enhancement. MR diffusion imaging can non-invasively quantify the average apparent diffusion coefficient (ADC(av)), a measure of water molecule random motion that is sensitive to pathological change in multiple sclerosis lesions and to abnormalities in the normal-appearing white matter (NAWM). We therefore used MR diffusion imaging to investigate the dynamic evolution of water diffusion measurements in new enhancing multiple sclerosis lesions, in the NAWM from which they arise, and in anatomically matched contralateral NAWM regions from which no visible lesions develop. Gadolinium diethylenetriaminepentaacetic acid (Gd)-enhanced MRI and MR diffusion studies were performed monthly for 1 year in five multiple sclerosis patients with clinically and radiologically active disease. The ADC(av) was calculated at each time point of the study (before, during and after lesion appearance on Gd-enhanced scans) for each new enhancing lesion, and for regions matched for size and position in the contralateral NAWM. A steady and moderate increase in ADC(av) in prelesion NAWM was observed, which was followed by a rapid and marked increase at the time of Gd enhancement and a slower decay after the cessation of enhancement. In matched contralateral NAWM regions there was a significant but milder increase in ADC(av) at the time of the first noted lesion enhancement. These findings indicate that new focal lesions associated with frank BBB leakage are preceded by subtle, progressive alterations in tissue integrity beyond the resolution of conventional MRI. The increases in ADC(av) in anatomically matched contralateral regions after lesions have appeared supports the concept that structural damage in lesions causes damage or dysfunction in connected areas of NAWM.

Adult↗
PubMed2000

Clinical appropriateness: a key factor in outcome measure selection: the 36 item short form health survey in multiple sclerosis.

OBJECTIVES: Understanding the properties of an outcome measure is essential in choosing the appropriate instrument and interpreting the information it generates. The MOS 36 item short form health survey questionnaire (SF-36) is widely acknowledged as the gold standard generic measure of health status; few studies however have evaluated its use for clinical trials in multiple sclerosis. Its clinical appropriateness, internal consistency reliability, validity, and responsiveness was investigated across a broad range of patients with multiple sclerosis. METHODS: A prospective study in which 150 adults with clinically definite multiple sclerosis completed a battery of questionnaires evaluating generic health status, disability, handicap, and emotional wellbeing. Of these, 44 patients undergoing inpatient rehabilitation completed the questionnaires before and after intervention to evaluate responsiveness. RESULTS: Score distributions demonstrated significant floor and ceiling effects in four of the eight dimensions which were particularly marked when patient selection was restricted to a narrow band of disease severity (as is the case in most clinical trials). Internal consistency exceeded the standard for group comparisons for all dimensions. Convergent and discriminant construct validity was supported by the direction, magnitude, and pattern of correlations with other health measures. In comparison with instruments measuring associated constructs, the responsiveness of the SF-36 was poor in evaluating change in moderate to severely disabled patients participating in a programme of inpatient rehabilitation. CONCLUSIONS: The SF-36 has some limitations as an outcome measure in multiple sclerosis. The results highlight the need for all instruments to be examined in the specific sample population under question and for the specific research question being investigated. In multiple sclerosis clinical trials, the SF-36 should be supplemented with other relevant measures.

Adult↗
PubMed2000

Recovery from optic neuritis is associated with a change in the distribution of cerebral response to visual stimulation: a functional magnetic resonance imaging study.

OBJECTIVES: Recovery to normal or near normal visual acuity is usual after acute demyelinating optic neuritis, despite the frequent persistence of conduction abnormalities as evidenced by the visual evoked potential (VEP). This raises the possibility that cortical adaptation to a persistently abnormal input contributes to the recovery process. The objective of this study was to investigate the pattern of cerebral response to a simple visual stimulus in recovered patients in comparison to normal subjects. METHODS: Functional magnetic resonance imaging (fMRI) was used to study the brain activation pattern induced by a periodic monocular 8Hz photic stimulus in seven patients who had recovered from a single episode of acute unilateral optic neuritis, and in seven normal controls. VEPs and structural optic nerve MRI were performed on patients. RESULTS: Stimulation of either eye in controls activated only the occipital visual cortex. However, in patients, stimulation of the recovered eye also induced extensive activation in other areas including the insula-claustrum, lateral temporal and posterior parietal cortices, and thalamus; stimulation of the clinically unaffected eye activated visual cortex and right insula-claustrum only. The volume of extraoccipital activation in patients was strongly correlated with VEP latency (r = 0.71, p = 0.005). CONCLUSIONS: The extraoccipital areas that were activated in patients all have extensive visual connections, and some have been proposed as sites of multimodal sensory integration. The results indicate a functional reorganisation of the cerebral response to simple visual stimuli after optic neuritis that may represent an adaptive response to a persistently abnormal input. Whether this is a necessary part of the recovery process remains to be determined.

Adult↗
PubMed2000

Lesion heterogeneity in multiple sclerosis: a study of the relations between appearances on T1 weighted images, T1 relaxation times, and metabolite concentrations.

OBJECTIVES: Multiple sclerosis lesions appear as areas of high signal on T2 weighted MRI. A proportion of these lesions, when viewed on T1 weighted MRI, appear hypointense compared with surrounding white matter. These hypointense T1 lesions are thought to represent areas of greater tissue damage compared with the more non-specific, total T2 lesion load. This study aimed to better characterise the properties of high signal T2 lesions with differing appearances on T1 weighted MRI using quantitative MR techniques. METHODS: Eleven patients with secondary progressive multiple sclerosis were studied. Two high signal T2 lesions were selected from each patient-one of which appeared hypointense and one isointense on a T1 weighted image. A voxel was positioned around each lesion and for this volume of brain the metabolite concentrations were estimated using proton MR spectroscopy ((1)H-MRS) and the T1 relaxation time within each voxel calculated from a T1 map generated using a multislice technique. RESULTS: Compared with isointense T1 lesions, hypointense T1 lesions exhibited a significantly lower absolute concentration of N-acetyl derived metabolites (tNAA) and a significantly higher absolute concentration of myo-inositol (Ins). T1 relaxation time correlated significantly with both tNAA (r=-0.8, p < 0.001) and Ins (r=0.5, p=0. 012). There was no correlation between T1 relaxation times and creatine/phosphocreatine or choline containing compounds. CONCLUSIONS: Prolonged T1 relaxation times seem to reflect the severity of axonal damage or dysfunction (inferred by a low tNAA) and possibly also gliosis (inferred by a high Ins) in chronic multiple sclerosis lesions.

Adult↗
PubMed2000

One year follow up study of primary and transitional progressive multiple sclerosis.

OBJECTIVE: To document clinical and magnetic resonance imaging (MRI) characteristics of a large cohort of primary and transitional progressive multiple sclerosis (PP and TP MS) patients over one year. INTRODUCTION: Patients with PP or TP MS have been shown to have low brain T2 and T1 lesion loads and slow rates of new lesion formation with minimal gadolinium enhancement, despite their accumulating disability. Serial evaluation of these patients is needed to elucidate the pathological processes responsible for disease progression and to identify clinical and MRI measures which can monitor these processes in treatment trials. METHOD: Patients, recruited from six European centres, underwent two assessments on the expanded disability status scale (EDSS) and MRI of the brain and spinal cord, 1 year apart. RESULTS: Of the 167 patients studied (137 with PP MS and 30 with TP MS), 41 (25%; 35 PP and six TP) showed a one step increase in the EDSS. The mean number of new brain lesions seen was 0.88 in the PP group and 0.47 in the TP MS group. Both groups demonstrated change in T2 lesion load over the year (p< or =0.002), with median percentage changes of 7.3% in the PP group and 10. 8% in the TP MS group. The PP group also showed a significant change in T1 load (p< 0.001, median change 12.6%). The number of new cord lesions seen was small (mean of 0.14 in the PP group and no new cord lesions in the TP group). Both groups demonstrated a decrease in cord cross sectional area (p< 0.001, median changes; PP 3.8%, TP 4. 9%), but only the PP group showed evidence of significant brain atrophy (p<0.001, 0.95%). CONCLUSION: Although the monitoring of disease progression in this patient group is difficult, this study demonstrates changes in both lesion load and atrophy, which, if shown to correlate with clinical change over a longer time will facilitate therapeutic trial design.

Atrophy↗
PubMed2000

Diffusion tensor imaging can detect and quantify corticospinal tract degeneration after stroke.

Diffusion tensor imaging (DTI) fully characterises water molecule mobility in vivo, allowing an exploration of fibre tract integrity and orientation in the human brain. Using DTI this study demonstrates reduced fibre coherence (anisotropy) associated with cerebral infarction and in the corticospinal tract remote from the lesion, in five patients 2 to 6 months after ischaemic stroke. The study highlights the potential of DTI to detect and monitor the structural degeneration of fibre pathways, which may provide a better understanding of the pattern of clinical evolution after stroke.

Adult↗
PubMed2000

Neuropsychological impairment in multiple sclerosis patients: the role of (juxta)cortical lesion on FLAIR.

In this study we evaluated the correlation between neuropsychological impairment (measured with the Brief Repeatable Battery Neuropsychological Tests) and (juxta)cortical lesions detected with FLAIR and the relative sensitivity of the FLAIR sequence compared to spin-echo MRI sequences in detecting (juxta)cortical MS lesions. A total of 39 patients with definite MS were evaluated by MRI with a conventional and fast spin echo sequence and fast FLAIR sequence, and neuropsychological tests of the Brief Repeatable Battery Neuropsychological tests were performed. The Z-score of all subtests were used to calculate a Cognitive Impairment Index. The results show that a high number of (juxta)cortical lesions is detected with thin slice FLAIR (30% of all lesions seen). This percentage was not superior to spin-echo, reflecting the thin slice thickness (3 mm) we used. The lesions detected with FLAIR were to a certain degree different ones than the lesions detected with the other techniques. While the number of non-cortical lesions correlated with the expanded disability status scale (r=0.32, P=0.045), the number of (juxta)cortical lesions detected with the FLAIR showed a correlation (r=0.34, P=0.035) with the Cognitive Impairment Index. Our study underlines the high number of (juxta)cortical lesions in MS and the value of thin slice FLAIR sequence to detect such lesions with MRI. It also stresses the importance of (juxta)cortical lesions on determining neuropsychological impairment. Multiple Sclerosis (2000) 6 280 - 285

Adult↗
PubMed2000

A questionnaire assessment of unmet needs for rehabilitation services and resources for people with multiple sclerosis: results of a pilot survey in five European countries. Needs Task group of MARCH (Multiple Sclerosis and Rehabilitation, Care and Health Services Research in Europe).

OBJECTIVE: To develop an international services and needs assessment instrument (SUN) for people with multiple sclerosis and their carers and to pilot this in different countries of the European Community. DESIGN: Interview study of people with multiple sclerosis, their carers and nominated key professionals examining the unmet needs of patients and carers. SETTING: Belgium, Estonia, Greece, Italy and the United Kingdom. MAIN OUTCOME MEASURES: Needs assessment questionnaire. RESULTS: The study comprised 137 people with multiple sclerosis, 125 carers and 111 professionals. Patients reported on average 2.9 unmet needs for themselves; their carers and professionals reported on average 2.4. Needs were categorized into seven broad categories. Due to difficulties experienced by the local researchers in distinguishing between needs and objectives a large proportion of needs had to be assigned to the 'other' category. CONCLUSIONS: The SUN is a valuable and practicable tool for the identification of unmet needs for people with multiple sclerosis and their carers. Formal validation and reliability testing of the different language versions is recommended.

Europe↗
PubMed2000

The incidence and significance of testicular microlithiasis in a subfertile population.

The objective of this study was to assess the frequency of testicular microlithiasis (TM) in infertile men who underwent testicular ultrasound and to determine any causative or associated factors. The case notes of 159 consecutive patients who were referred for testicular ultrasound in the investigation of male factor infertility were reviewed. Microcalcification was found in 10 cases (6.2%). This was unilateral in all cases and six patients had clinical evidence of a varicocele. Five cases had minimal calcification and five had marked TM. On patient had a past history of testicular maldescent and another of testicular torsion. Sperm function (as assessed by sperm count, motility and the sperm migration test) was variable within the 10 patients and there was no correlation with hormone profiles or testicular size. There was a statistical difference between a number of investigations in those patients with minimal degrees of calcification and those with TM (sperm migration test (SMT), namely sperm migration and sperm motility (p < 0.05, Mann-Whitney U test)). The results showed a higher than expected incidence of TM. Patients with marked TM seemed to have poorer sperm function than those with minimal calcification. There was a high incidence of co-existing pathology, for instance scrotal varicocele and cryptorchidism, although the numbers in this study were small and further studies need to be carried out to determine the exact nature and significance of this condition.

Gonadal Steroid Hormones↗
PubMed2000

Congenital lobar emphysema occurring in twins.

Twins born with congenital lobar emphysema are reported. This has not previously been described. Diagnosis, surgical management and subsequent course is high-lighted. These twins may well be the smallest to have operative treatment.

Cesarean Section↗