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Biomedical subjects

M Swash

Publications and source records attributed to M Swash.

At least 163 records · Page 9Linked to original sources
PubMed1988

Ultrastructural changes in internal anal sphincter in neurogenic faecal incontinence.

The ultrastructural features of the internal anal sphincter (IAS) muscle were studied in biopsies from five patients with neurogenic anorectal incontinence and six control subjects undergoing anorectal excision for cancer, or for inflammatory bowel disease. In the patients with idiopathic neurogenic anorectal incontinence the internal anal sphincter showed loss of smooth muscle cells, disruption of the normal relationships of the remaining cells, stretching of elastic tissue, and increased collagen fibril content. These ultrastructural changes in the morphology of the internal anal sphincter, although probably not the primary cause of faecal incontinence, have functional relevance in the clinical syndrome, as shown by the reduction in resting anal canal pressure found in some patients with this syndrome.

Adult↗
PubMed1988

Constipation and paradoxical puborectalis contraction in anismus and Parkinson's disease: a dystonic phenomenon?

Anismus, or constipation due to functional obstruction at the pelvic outlet by paradoxical contraction of the striated sphincter muscles during defaecation straining, is described in ten constipated patients and four patients with Parkinson's disease and constipation. The dysfunctional pattern of muscle recruitment resembled that characteristic of dystonia elsewhere in the body and was indistinguishable in patients with idiopathic anismus and those with extrapyramidal motor disturbance due to Parkinson's disease. These findings suggest that anismus may be a focal dystonic phenomenon.

Adult↗
PubMed1988

Preclinical and subclinical events in motor neuron disease.

It is suggested that in motor neuron disease there is a long preclinical period of relative tolerance and compensation before presentation with apparently focal features. During this phase the disease becomes disseminated through the motor system. The mode of acquisition of the disease, its relation to a possible genetic factor, and the processes leading to tolerance, to latency or progression, to the relative involvement of upper and lower motor neurons, to involvement of spinocerebellar pathways, and to asymmetry are fundamental problems in understanding the disease.

Adult↗
PubMed1988

Bell's palsy and HIV infection.

Unilateral infranuclear facial palsy developed in three young homosexual men. All three were positive for antibodies to human immunodeficiency virus (HIV). Two had persistent generalised lymphadenopathy, but the clinical criteria for the acquired immune deficiency syndrome (AIDS) were not fulfilled. There were no features of generalised neuropathy, and no other cause for facial palsy was evident. Recovery was excellent in each patient.

AIDS-Related Complex↗
PubMed1988

Central motor conduction in multiple sclerosis: evaluation of abnormalities revealed by transcutaneous magnetic stimulation of the brain.

Magnetic stimulation of the brain and spinal column was used to assess conduction in the descending central motor pathways controlling arm and leg muscles of 20 patients with multiple sclerosis, and 10 normal subjects. The multiple sclerosis patients had relapsing and remitting disease but all were ambulant and in stable clinical remission. Increased central motor conduction times (CMCTs), up to three times normal, were frequently encountered in multiple sclerosis patients and in leg muscles these correlated closely with clinical signs of upper motor neuron disturbance; in the upper limb muscles a higher proportion of subclinical lesions was present. Weak muscles were almost invariably associated with abnormal central conduction but increased CMCTs were also found for 52 of the 104 muscles with normal strength. CMCTs for lower limb muscles were directly related (p less than 0.005) to functional motor disability (Kurtzke and Ambulatory Index Scales). No patient developed clinical evidence of relapse during follow-up of at least 8 months. Magnetic brain stimulation is easy to perform, painless, and safe, and provides clinically relevant information in the diagnosis and monitoring of multiple sclerosis patients.

Adult↗
PubMed1988

Comparison of sporadic and familial disease amongst 580 cases of motor neuron disease.

A review of 580 hospital case notes of patients with motor neuron disease (MND) revealed 20 families in which more than one case had been reported. For 27 of the cases in these families full medical records were available, and a history of a further 37 affected family members were obtained. The cases in these 20 families are termed familial and the remainder sporadic. Parent to child transmission occurred in 16 of the 20 families of the familial cases, suggesting autosomal dominant inheritance. In three families there was involvement of siblings only, and in one family two cousins were affected. The sex ratio for the documented familial case records seen was 0.8:1 (M/F = 12:15), for the total (documented and historical) it was 1.06:1 (33:31), but in sporadic cases it was 1.6:1 (341:212) and more frequent occurrence of sensory features at presentation was reported in the familial cases (15% in the familial cases and 5% in the sporadic cases). However, none of these differences reached statistical significance. Familial cases also differed from sporadic cases in having a younger age of onset (a mean of 52 years in the familial cases compared with 56 years in the sporadic) and in the shorter median reported duration of illness (1.1 year in the familial cases; 2.6 years in the sporadic). However, in only one fifth of sporadic cases was the age at onset and death known, although this was known for 22 of the 27 familial cases, so that the data on survival and age of onset are too incomplete to test formally.

Age Factors↗
PubMed1988

Selective and asymmetric vulnerability of corticospinal and spinocerebellar tracts in motor neuron disease.

The spinal cords of 10 cases of motor neuron disease were compared with those of six age-matched controls using myelin and silver impregnation methods, and the Marchi reaction for myelin degradation products. These studies revealed striking asymmetry in involvement of the lateral and anterior corticospinal tracts, without concordance in the pattern of involvement of these crossed and uncrossed corticospinal pathways. In addition there was prominent involvement of the posterior and anterior spinocerebellar tracts, but less marked abnormality was seen in the reticulospinal pathways. These findings highlight the asymmetrical involvement of the upper and lower motor neuron components of the motor system that is a characteristic feature of the disease, and demonstrate that involvement of the spinocerebellar system is a frequent finding.

Anterior Horn Cells↗
PubMed1987

Parity as a factor in incontinence in multiple sclerosis.

Twelve consecutively selected patients with multiple sclerosis and incontinence had electrophysiologic studies performed of the pudendal and perineal innervations of the anal and urinary sphincter. Single-fiber electromyogram density measurements were obtained in the external anal sphincter. Fecal incontinence was found to be unexpectedly frequent. The results suggest that incontinence in patients with multiple sclerosis is often due to the interaction of several factors, including central lesions, lesions of the conus medullaris and, also, coincidental pelvic nerve lesions associated with childbirth. Thus, incontinence is especially a problem in women with this disease.

Action Potentials↗
PubMed1987

Neural control of internal anal sphincter function.

The effect on anal tone of electrical stimulation of the presacral (hypogastric) sympathetic nerves has been studied in eight patients during abdominal rectopexy or restorative proctocolectomy. A sharp fall in anal pressure occurred in seven patients (mean fall 59 cmH2O; range 35-80 cmH2O). In one patient given a beta- and alpha-sympathetic blocking drug (labetalol 200 mg) intra-operatively, the anal pressure decreased by 15 cmH2O. These observations show that stimulation of the presacral sympathetic nerves causes relaxation of the internal anal sphincter and implies that these nerves may induce relaxation of the sphincter in vivo. The pathway of the recto-anal reflex has been studied intra-operatively in three patients undergoing rectal excision. The recto-anal reflex is present after presacral nerve blockade and after full mobilization of the rectum, but is abolished by circumferential rectal myotomy. The reflex has a local intramural pathway. This observation validates the assumption that absence of this reflex is a feature of aganglionosis, as in Hirschsprung's disease.

Adrenergic Fibers↗
PubMed1987

Juvenile-onset bulbospinal muscular atrophy with deafness: Vialetta-van Laere syndrome or Madras-type motor neuron disease?

A girl with rapid-onset, bulbospinal muscular atrophy and deafness is described. The patient's mother and brother showed EMG features consistent with subclinical involvement. T is bulbospinal form of spinal muscular atrophy associated with deafness described by Vialetto and van Laere closely resembles the Madras type of motor neuron disease, also associated with deafness, described by Jagganathan and colleagues.

Adolescent↗
PubMed1987

Selective vulnerability of urinary Onuf motoneurons in Shy-Drager syndrome.

Electrophysiological investigations in a patient with progressive autonomic failure revealed selective damage to the somatic efferent innervation of the external urinary sphincter musculature, implying selective vulnerability of the motoneurons of Onuf's nucleus in the sacral cord. This vulnerability contrasts with the selective resistance of these motoneurons to degeneration in motor neuron disease.

Anal Canal↗
PubMed1987

Muscle pathology in the neuroleptic malignant syndrome.

In a fatal case of neuroleptic malignant syndrome, a muscle sample taken within 1 h of death showed acute myopathic features with absence of muscle glycogen and neutral lipid. These features suggest that hyperpyrexia in this syndrome may be caused by heat production from uncoupled phosphorylation in muscle and imply that the primary biochemical abnormality responsible for this uncontrolled heat production might be muscular rather than hypothalamic.

Adult↗
PubMed1987

Relation between perineal descent and pudendal nerve damage in idiopathic faecal incontinence.

In 60 patients with idiopathic anorectal incontinence, without neurological disease, there was a significant relationship, shown by regression analysis, between the pudendal nerve terminal motor latency and the extent of perineal descent during straining (r 0.59; p less than 0.001), and the plane of the perineum on straining (r -0.61; p less than 0.001). These data are consistent with the suggestion that perineal descent can lead to stretch-induced damage to the perineal nerves in this condition.

Action Potentials↗
PubMed1987

Is paradoxical contraction of puborectalis muscle of functional importance?

Paradoxical contraction of the puborectalis muscle during simulated defecation straining (anismus) has been cited as a cause of constipation. The functional specificity of this phenomenon was evaluated in 79 patients, 50 with constipation, 21 with idiopathic perineal pain, and eight with solitary rectal ulcer syndrome. Electromyogram evidence of paradoxical puborectalis contraction was observed in 38 (76 percent), ten (48 percent), and four (50 percent) of these patients, respectively. All patients with solitary rectal ulcer syndrome had difficulty defecating; defecation was normal in all patients with perineal pain. These observations suggest that paradoxical contraction of the puborectalis muscle is not a specific finding, and that it is not the sole cause of constipation in patients with anismus.

Adolescent↗
PubMed1987

The double collision technique: a new method for measurement of the motor nerve refractory period distribution in man.

A new, double collision, technique is described for non-invasive measurement of the motor nerve refractory period distribution for human peripheral nerves. In contrast to previous collision techniques, this method is independent of the transient changes in nerve and muscle fibre conduction which can distort test muscle responses. The end-point of the distribution is determined by a null response; this permits accurate identification of those nerve fibres with the longest refractory periods. We have used the double collision technique to measure the refractory period distributions for the median nerve at the wrist in 20 normal subjects aged between 22 and 58 (mean 35) years. 150% maximal stimuli were used with a controlled limb temperature of 35 degrees C. Following a conditioning stimulus, the mean latencies for recovery of 5%, 50%, 95% and 99% of motor nerve fibres were 0.94, 1.03, 1.12 and 1.23 msec respectively. Data are also presented for the ulnar and peroneal nerves. The results show that the human motor nerve refractory period distribution is much less dispersed than has been previously supposed.

Adult↗
PubMed1987

Motor nerve conduction velocity distributions in man: results of a new computer-based collision technique.

A new computer-based collision technique for direct measurement of the human motor nerve conduction velocity distribution is described. In contrast to previous collision techniques, the test muscle response is progressively cancelled to a null using an arrangement of proximal and distal stimuli which eliminates distortion of the test response caused by transient changes in nerve and muscle fibre conduction. The increased sensitivity of this new technique permits accurate measurement of the slowest 1% of alpha motor nerve fibres. We have used our modified collision technique to determine motor nerve conduction velocity distributions for the median nerve in 20 normal subjects aged between 19 and 59 (mean 35) years. 150% maximal stimulus intensities were used, with a controlled limb temperature of 35 degrees C. Group mean velocities (+/- S.D.) for the fastest (95%), mean (50%) and slowest (5% and 1%) motor fibres were 59.1 +/- 3.0, 56.9 +/- 2.9, 52.7 +/- 3.1 and 51.2 +/- 3.7 m/sec respectively. Data are also presented for the ulnar and peroneal nerves.

Action Potentials↗