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Biomedical subjects

M Swash

Publications and source records attributed to M Swash.

At least 127 records · Page 7Linked to original sources

Microdissection: a novel method for the study of intracellular inclusion bodies.

The purification of many intracellular and extracellular inclusions is often difficult to achieve due to the low concentration of the abnormalities in the tissue under study, or due to the degradation of components during extraction. We describe the use of microdissection for the isolation of neurons and intraneuronal inclusion bodies. The resulting suspension may be used for biochemical, immunological or ultrastructural studies. The technique is applicable to the study of a wide range of cellular abnormalities.

Cytological Techniques↗

Myopathy of internal anal sphincter with polyglucosan inclusions.

In two members of an affected family with a hereditary syndrome of proctalgia fugax and constipation, a hypertrophied internal anal sphincter was found with histological features suggesting a myopathy of this muscle. In these two patients, and in an unrelated patient with a similar clinical syndrome, smooth muscle fibres of the internal anal sphincter showed numerous vacuoles, many of which contained ovoid inclusion bodies. The structural features and histochemical reactions of the inclusion bodies were consistent with a polyglucosan composition. Histological examination of the internal anal sphincter may reveal smooth muscle abnormalities in functional bowel disorders.

Adult↗

Exertional myocardial ischemia in diabetes: a quantitative analysis of anginal perceptual threshold and the influence of autonomic function.

Patients with diabetes are prone to silent myocardial infarction and silent exertional ischemia. Although the mechanism is not clear, it may reflect a specific impairment of the sensory innervation of the heart. To test this hypothesis, anginal perceptual threshold was measured in 32 diabetic patients and 36 nondiabetic control patients, all of whom had typical exertional angina. Anginal perceptual threshold was defined as the time from onset of 0.1 mV ST depression to the onset of chest pain during treadmill stress electrocardiography. Although ST depression occurred earlier in the diabetic than in the nondiabetic group (111 +/- 82 versus 216 +/- 162 s, p less than 0.005), the anginal perceptual threshold in the diabetic group was delayed by a mean of 86 s (149 +/- 76 versus 63 +/- 59 s, p less than 0.001), with 95% confidence intervals of 53 to 119 s. Autonomic function tests were abnormal in the diabetic group, and in both groups regression analyses (using a third order polynomial) showed marked prolongations of anginal perceptual threshold as the heart rate responses to the Valsalva maneuver decreased to below the normal range (r = 0.5, p less than 0.001). There was a similar though less pronounced relation between anginal perceptual threshold and the heart rate responses to deep breathing (r = 0.3, p less than 0.02). These data suggest that prolongation of the anginal perceptual threshold may be caused by autonomic neuropathy involving the sensory innervation of the heart. To test sensory function, median nerve conduction studies were performed in 19 patients (10 diabetic and 9 nondiabetic).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗

Spinal cord trauma in man: studies of phosphorylated neurofilament and ubiquitin expression.

Changes in neuronal proteins are a major feature of the neurodegenerative disorders, but the biological significance of these changes is not understood. We describe alterations in neuronal proteins as a result of surgical tractotomy on the human spinal cord at 3, 5, 7, 14 and 72 days after operation. Antibodies to phosphorylated neurofilaments labelled neuronal cell bodies in the nucleus dorsalis and anterior horns. Axonal swellings showed positive staining for ubiquitin, but ubiquitinated neuronal inclusions were not evident. The presence of phosphorylated neurofilaments in the neuronal cell bodies and of ubiquitination of axonal swellings may be indicators of interrupted axonal transport. The changes found in intracellular proteins in neurons after trauma do not resemble those found in motor neuron disease, suggesting that the intraneuronal ubiquitinated inclusions may have a unique significance in the cytopathology of that disorder.

Humans↗

New insights in motor neuron disease.

In motor neuron disease there is a characteristic pattern of nerve cell loss and degeneration of related pathways. In surviving anterior horn cells several morphologically distinct, but generally non-specific, intracytoplasmic inclusion bodies have been recognized. Recently accumulations of previously unrecognized ubiquitinated material have been described in surviving neurons, which cannot be demonstrated with routine histological methods. These changes appear unique to this disease, and provide a new insight into the underlying pathology that may help understand the pathogenesis of this intriguing disorder. In this article we review the new information on the clinical, toxicological and pathological features of the disease.

Animals↗

Electrophysiology of motor pathways for sphincter control in multiple sclerosis.

The central and peripheral motor pathways serving striated sphincter muscle function were studied using cortical and lumbar transcutaneous electrical stimulation, pudendal nerve stimulation and sphincter electromyography in 23 patients with multiple sclerosis (MS), and sphincter disturbance, including incontinence of urine or faeces, urinary voiding dysfunction, or constipation. The central motor conduction time was significantly increased in the MS group compared to controls (p less than 0.05). Damage to both the upper and lower motor neuron pathways can contribute to sphincter disturbance in MS. The latter may be due to coexisting pathology or to involvement of the conus medullaris by MS.

Adult↗

Clinical features and associations of 560 cases of motor neuron disease.

In 560 cases of motor neuron disease, studied retrospectively from their case notes in three teaching centres, the age at onset ranged from 13 to 87 years (mean 56 years), and the mean duration of illness until death was 2.6 years. In the subgroup of the disease presenting with progressive bulbar palsy presenting after age 59 years, there was a previously unrecognised excess of females sufficient to equalize the sex ratio of incidence of the disease in this age group. No potentially causative clinical associations emerged; no relation was noted between occupational exposure to leather products, trauma or surgical procedures and the disease. There was a trend for patients with motor neuron disease to give a history of abstention from alcohol.

Adult↗

Feasibility of percutaneous transluminal angioplasty for carotid artery stenosis.

Percutaneous transluminal balloon angioplasty was attempted in seven patients with internal carotid artery stenosis, including one patient who had two procedures. All had recurrent, carotid territory, neurological symptoms considered haemodynamic in origin. Six had occlusion of the contralateral internal carotid artery. Cerebral blood flow studies confirmed diminished cerebrovascular reserve in six patients studied. In five patients (six procedures) angioplasty of the stenosed internal carotid artery was carried out successfully. With two patients technical difficulty in crossing the stenosis prevented angioplasty and in one patient with bilateral stenosis the procedure was not attempted on the second side because of the severity of the stenosis. In two patients transient aphasia developed during cannulation of the carotid artery and in another a transient monoparesis developed during the procedure. Both these haemodynamic complications recovered within ten minutes. No other complications occurred. Our experience suggests that balloon angioplasty is technically feasible in the management of stenotic carotid disease associated with haemodynamic stroke. It is a technically simple procedure requiring only a brief admission to hospital. However, its general application to patients with thromboembolic carotid-territory stroke will depend on the risk/benefit ratio compared to carotid endarterectomy or to conventional medical treatment.

Angiography, Digital Subtraction↗

Cerebellar syndrome with hydrocephalus due to Mycoplasma pneumoniae infection.

A 27 year old woman developed a cerebellar syndrome with serological evidence of recent Mycoplasma pneumoniae infection. The cranial computed tomographic scan showed effacement of the fourth ventricle, enhancement of the basal meninges and hydrocephalus affecting the lateral and third ventricles. Clinical and radiological recovery occurred over 5 weeks. We propose that this was a manifestation of immune-mediated encephalomyelitis induced by the infection rather than direct invasion of the central nervous system.

Adult↗

Seizure induction by alcohol in patients with epilepsy experience in two hospital clinics.

We surveyed 70 epileptic patients attending a general neurology clinic and 64 patients attending an epilepsy clinic to determine the incidence of alcohol-related seizures. Seven (10%) of the neurology clinic patients and 9 (15%) of the epilepsy clinic patients reported exacerbation of their seizures with alcohol. In the first group, two had been heavy drinkers when under-age, two had features of alcohol dependence, and three had experienced resolution of seizures following cessation of their drinking. In the second group, five drank 4 units/day or more, and one drank more heavily. The importance of alcohol in the causation of these patients' seizures had not previously been appreciated. The relationship of alcoholism to epilepsy has been recognized for many years, but the role of alcohol in the exacerbation of primary epilepsy, and in triggering seizures in epileptic patients is often not recognized. Control of alcohol ingestion is an important factor in the management of epilepsy.

Adolescent↗

Anal sphincter dysfunction in Parkinson's disease.

Striated anal sphincter function was studied electrophysiologically and radiologically in six patients with Parkinson's disease and chronic constipation. In five cases, there was paradoxic anal sphincter muscle contraction during simulated defecation straining resembling anismus-type pelvic outlet obstruction. Radiologic studies showed functional improvement of the defecatory mechanism following the administration of the dopamine receptor agonist apomorphine in four patients. Dysfunction of the striated anal sphincter musculature may be a significant cause of constipation in some parkinsonian patients, occurring as part of the generalized extrapyramidal motor disorder.

Anal Canal↗

Anorectal physiology validated: a repeatability study of the motor and sensory tests of anorectal function.

Sixteen subjects (mean (s.d.) age 50.7 (12.8) years, three men) were studied on two separate occasions by two experienced investigators in random order. A standard protocol of anatomical, manometric and electrophysiological assessments of anorectal motor and sensory function was followed. No significant differences were found between the results obtained by the two investigators in the measurements of perineal descent, anal canal length, and canal resting pressure and squeeze pressure, pudendal nerve terminal motor latency, single-fibre electromyography fibre density of the external anal sphincter, and thresholds of mucosal electrosensitivity. This study shows that the standard tests of anorectal sensorimotor function are repeatable by different investigators. In addition, it suggests that comparison of data obtained in different centres using these techniques is valid.

Adult↗

Effects of aging on the anorectal sphincters and their innervation.

The effects of aging on the pelvic floor musculature and its innervation are described in 102 women and 19 men without colorectal or pelvic floor disease. In the women, a reduction in anorectal "squeeze" pressure was found in the fifth decade, but the resting anal pressure remained unchanged. This reduction in squeeze anal pressure was accompanied by an increase in the mean pudendal nerve terminal motor latency, indicating damage to this nerve, and increased perineal descent in the resting and straining positions. The fiber density, recorded by single fiber electromyography in the external anal sphincter muscle, a muscle innervated by the pudendal nerves, was increased in the sixth decade, indicating the later development of compensatory reinnervation in this muscle. The interrelation of aging, menopausal effects, and parity in these changes is difficult to define from currently available data, but the authors suggest, from other evidence, that menopausal effects may be relevant.

Adult↗

Cytoskeletal abnormalities in motor neuron disease. An immunocytochemical study.

Immunocytochemistry with antibodies against cytoskeletal proteins has been used to search for molecular differences in the spinal cord from patients with motor neuron disease (MND) of amyotrophic lateral sclerosis type and normal spinal cord. Monoclonal antibodies which recognize phosphorylated neurofilament epitopes diffusely labelled a proportion of normal and MND anterior horn cells, but did not permit differentiation between normal and MND tissue. However, in some MND and control anterior horn cells, dense 'floccular' accumulations were labelled by antibodies recognizing phosphorylated neurofilament epitopes. These accumulations of phosphorylated neurofilaments suggest abnormalities of cytoskeletal regulation, but were neither a common nor a specific feature of MND. Axonal spheroids, which were as common in normal as in MND tissue, were labelled by all antineurofilament antibodies. Normal-appearing axons, but not spheroids, in MND and control tissue were identified by an antiactin antibody, indicating that actin may be absent from the cytoplasmic domain which gives rise to spheroids. In summary, we have not found specific posttranslational changes of cytoskeletal proteins in MND and, in particular, phosphorylated neurofilament epitopes are common to both MND and control anterior horn cells.

Adult↗

Idiopathic dystonia and cervical spondylotic myelopathy.

Cervical myelopathy developed in two patients with idiopathic torsion dystonia. There were marked spondylotic changes in both patients, probably attributable to the incessant dystonic movements of the neck. Previous cervical spine surgery may have exacerbated the myelopathy in one of the patients. Cervical myelopathy complicating idiopathic dystonia must be distinguished from other causes of neurological deterioration, since it may be improved by appropriate neurosurgical treatment.

Adult↗