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Biomedical subjects

M Swash

Publications and source records attributed to M Swash.

At least 181 records · Page 10Linked to original sources

Tuberculous meningitis: role of CT in management and prognosis.

Serial computed tomographic scans were performed during the course of tuberculous meningitis in 25 patients aged 1-70 years. Hydrocephalus rarely occurred without other abnormalities. Marked ventricular enlargement was associated with extensive basal enhancement. Basal meningeal enhancement was not a good indicator of the clinical state although marked enhancement was a risk factor for the development of basal ganglia infarction. Infarcts were much more common in children than in adults and were sometimes asymptomatic. Radiological abnormalities sometimes developed during treatment and often did not resolve completely. Many patients had severe residual neurological problems.

Adolescent↗

Central motor conduction is abnormal in motor neuron disease.

Conduction in the central motor pathways of the brain and spinal cord was studied in 12 patients with motor neuron disease. Six healthy volunteers served as controls. Transcutaneous electrical stimulation of the cortex, cervical cord, thoracic cord and conus medullaris was used to determine motor latencies to the biceps brachii, thenar eminence and tibialis anterior muscles. Prominent, and often asymmetrical, slowing of central motor conduction was demonstrated in seven of the 12 patients; these findings were most marked in the spinal cord and in most cases correlated with clinical features of corticospinal involvement. In general it was more difficult to excite motor pathways in the central nervous system in the patients with motor neuron disease than in control subjects. Evidence of subclinical involvement of central motor pathways was found in five patients. The central lesion in motor neuron disease may thus contribute more significantly to the clinical deficit than has been realised, since the clinical signs of the upper motor neuron lesion are often masked by the more obvious lower motor neuron features.

Adult↗

Differential diagnosis of motoneurone disease from other neurological conditions.

Analysis of 422 patients with clinical diagnoses of motoneurone disease (MND), multiple sclerosis, cervical spondylosis with myelopathy, or stroke, from two referral centres, suggested a simple four-step algorithm for diagnosing MND. The algorithm provided a 98% sensitivity (true positive diagnosis) and 86% specificity, and therefore gives a baseline for diagnostic criteria suitable for use in clinical research of MND.

Algorithms↗

Brain-stem auditory evoked responses in diagnosis of central pontine myelinolysis.

Central pontine myelinolysis (CPM) developed in association with acute adrenocortical insufficiency during correction of severe hyponatraemia in a 58-year-old woman. Repeated CT scanning and NMR imaging were normal from the onset of the illness. Electroencephalography and brain-stem auditory evoked responses showed abnormalities consistent with a brain-stem lesion, which resolved as the patient made a gradual but incomplete recovery. Our observations illustrate the value of electrophysiological monitoring in CPM and support the proposed association between this condition and the rapid correction of an electrolyte imbalance.

Adrenal Insufficiency↗

Diagnosis of brachial root and plexus lesions.

The diagnosis and management of lesions of the brachial roots and of the brachial plexus is improved by appropriate investigation, both in acute and chronic disorders. The choice of investigation should be determined by the clinical problem. Since they are relatively non-invasive, electrophysiological investigations are particularly useful. In this review the role of these investigations is considered in relation to diagnosis and management.

Action Potentials↗

Origin and significance of small muscle fibres in neuromuscular disease.

Small muscle fibres, defined as those of less than 40 microns diameter in the male and 30 microns in the female were encountered in muscle biopsies of patients with spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), polymyositis (PM) and myopathy/dystrophy. Excessive reactivity with NADH-TR in small fibres did not discriminate between neurogenic and myopathic disorders. Quantification of perifascicular atrophic fibres, the number of nuclei in atrophic fibres, or the presence of isolated or grouped small fibres without histochemical kinship to their surrounding fibres did not aid recognition of the disease process in the groups studied. Small fibres which reacted strongly both with NADH-TR and ATPase at pH 9.4 (Type 3 fibres) constituted 38% of small fibres in the biopsies of SMA; 25% in ALS; but only 1% and 2.7% in PM and myopathy/dystrophy respectively. Thus, the presence of small Type 3 fibres in muscle biopsies may be a useful marker for neurogenic disorders in adults.

Adenosine Triphosphatases↗

Risk factors in childbirth causing damage to the pelvic floor innervation.

The innervation of the pelvic floor musculature is damaged in both stress urinary incontinence and idiopathic (neurogenic) anorectal incontinence. Because childbirth has been considered to be a causative factor in stress incontinence we have assessed the effect of childbirth on the innervation of the pelvic floor musculature in 122 consecutively referred women. They were investigated 48-72 h and 2 months after delivery; 51 were also studied 6 months prior to delivery. In 45 of these 51 women delivered vaginally, EMG studies of the external anal sphincter muscle showed that the fibre density (FD) increased from 1.38 +/- 0.14 before delivery to 1.57 +/- 0.19 2 months after delivery (p less than 0.01). There was no change in the FD in the external anal sphincter muscle after delivery in 20 women delivered by Caesarean section. The pudendal nerve terminal motor latency (PNTML) measured 48-72 h after delivery was increased in the 102 women delivered vaginally compared to 34 nulliparous control subjects. Analysis of the whole group of 122 women showed that multiparity, forceps delivery, increased duration of the second stage of labour, third degree perineal tear and high birth weight were important factors leading to pudendal nerve damage. Epidural anaesthesia had no effect on pudendal nerve function. Modification of these obstetric risk factors may ultimately reduce the frequency of stress urinary and faecal incontinence in women.

Adolescent↗

Focal loss of anterior horn cells in the cervical cord in motor neuron disease.

In a three-dimensional study of the distribution of anterior horn cells in the C8 segment of the human spinal cord we have recognized lateral and medial zones of motor neuron groupings, but have not been able to recognize subgroups of neurons within these groupings resembling the anatomical columns described by earlier investigators. This observation does not invalidate the concept of functional groupings within these anterior horn cell pools. In studies of the same segment in cords obtained at autopsy from patients with motor neuron disease, zones of focal loss of motor neurons were identified, without consistent severity or distribution at different sectional levels. These findings imply varying resistance to the disease in different pools of motor neurons.

Aged↗

Assessing intellectual deterioration.

Twenty patients fulfilling the clinical criteria of Alzheimer-type dementia were assessed on the Wechsler Adult Intelligence Scale (WAIS), the Schonell Graded Word Reading Test (SGWRT) and the National Adult Reading Test (NART). Fifteen normal elderly control subjects were administered the WAIS and the NART. The regression equations of Nelson & McKenna (1975) and the tables of Nelson (1982) were used to estimate premorbid Full Scale IQ on the basis of WAIS Vocabulary subtest score and performance on each of the reading tests. The data were analysed in order to assess the relative utility of these methods, and of WAIS Verbal-Performance IQ discrepancy, in the assessment of intellectual deterioration. The data suggested that performance on the NART was the best indicator of premorbid level of functioning in terms of the size of predicted-obtained discrepancies.

Aged↗

Intrusion errors in Alzheimer's disease.

The Kendrick Object Learning Test (OLT) was used to study the incidence of intrusion errors in patients with Alzheimer's disease (AD). Although such errors constituted a higher proportion of the responses made by patients than by controls, suggestions in the literature that patients with AD show a propensity for prior-list intrusion errors were not supported.

Aged↗

Immunohistochemical analysis of mononuclear cell subsets in inflammatory and non-inflammatory myopathies.

Immunohistochemical procedures were used to analyse the subpopulations of mononuclear cells in muscle biopsies from 24 patients with polymyositis. The character of the cellular infiltrate was similar at the perivascular, perimysial, and endomysial sites, with cytotoxic-suppressor T lymphocytes (T8+) and macrophages being the dominant elements. Helper T lymphocytes (T4+) and B lymphocytes were present in smaller numbers. A control series of 17 muscle biopsies from normal subjects and patients with non-inflammatory myopathies and neurogenic conditions was also studied: the numbers of mononuclear cells present were much smaller than in polymyositis, but the ratio of T4:T8 lymphocytes was similar to that found in biopsies affected by polymyositis. We conclude that both cytotoxic-suppressor T lymphocytes and macrophages are important in the pathogenesis of inflammatory myopathy.

Adolescent↗

Slowed motor conduction in lumbosacral nerve roots in cauda equina lesions: a new diagnostic technique.

New techniques have been developed for the electrophysiological assessment of patients with suspected cauda equina lesions using transcutaneous spinal stimulation (500-1500 V: time constant 50 microseconds) to measure motor latencies to the external and sphincter and puborectalis muscles from L1 and L4 vertebral levels. These latencies represent motor conduction in the S3 and S4 motor roots of the cauda equina between these levels. Similarly motor latencies can be recorded from spinal stimulation to the anterior tibial muscles (L4 and L5 motor roots). Transrectal stimulation of the pudendal nerves is used to measure the pudendal nerve terminal motor latency. In 32 control subjects, matched for age and sex, mean motor latencies from L1 and L4 spinal stimulation were 5.5 +/- 0.4 ms and 4.4 +/- 0.4 ms (mean + SD). In the 10 patients with cauda equina disease including ependymoma, spinal stenosis, arachnoiditis and trauma, these latencies were 7.2 +/- 0.8 ms and 4.6 +/- 0.9 ms, a significant increase in the L1 latency. The L1/L4 latency ratios to the puborectalis muscle were 1.36 +/- 0.09 in control subjects and 1.72 +/- 0.13 in cauda equina patients. Pudendal nerve terminal motor latencies were normal in eight of the 10 patients with cauda equina disease. The single fibre EMG fibre density in the external and sphincter muscle (normal, 1.5 +/- 0.16) was increased in patients with cauda equina lesions (1.73 +/- 0.28), but was increased more than two standard deviations from the mean only in three patients. This increase in fibre density was not of diagnostic value since it was also found in two of the four patients with low back pain. Slowing of motor conduction in the cauda equina is thus a useful indication of damage to these intraspinal motor roots. These investigations can be used in the selection of patients for myelography, and to follow progress in patients managed conservatively.

Adult↗

John Hughlings-Jackson: a sesquicentennial tribute.

One hundred and fifty years have elapsed since the birth of John Hughlings-Jackson, a pivotal figure in the development of clinical neuroscience. In this review the origin of Jackson's postulate of a hierarchical organisation of function in the nervous system is described in the context of his education and his contacts with contemporaries, both in his clinical practice at The London Hospital and at the National Hospital, Queen Square, and in relation to the evolutionary approach to the organisation and ideas on biology and society set out by the philosopher Herbert Spencer.

England↗

The innervation of the muscles of continence.

Electrophysiological evidence is presented that suggests that the innervation of the human puborectalis muscle differs from that of the external anal sphincter muscle. The latter is innervated by branches of the pudendal nerves, and the former by direct branches of the sacral plexus that enter the muscle from its pelvic surface. The striated urinary sphincter musculature also receives a dual innervation. The periurethral component is innervated by perineal branches of the pudendal nerves and the intramural portion by a different pathway, probably consisting of supralevator branches derived from the pelvic nerves. These findings are relevant to understanding the embryological derivation of these muscles and have practical importance in the surgery of this region of the body, particularly in the treatment of incontinence.

Adult↗