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.

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)

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.

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.

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.

Intrathecal baclofen and the H-reflex

Baclofen was given intrathecally to six patients with severe lower limb spasticity due to traumatic spinal cord injury. The effects of the drug on spasticity and the ratio between the maximum amplitude of the H reflex and the M response from the soleus (Hmax/Mmax ratio) were assessed. In each patient, spasticity was reduced following intrathecal baclofen and in four patients there was a reduction in the amplitude of the H reflex and Hmax/Mmax ratio. These results suggest that the Hmax/Mmax ratio may be helpful in establishing optimum drug dosage, particularly when the drug is used on a chronic basis.

Relative efficacy of intravenous methylprednisolone and ACTH in the treatment of acute relapse in MS

To compare the efficacy of high-dose intravenous methylprednisolone with intramuscular ACTH in the treatment of acute relapse in multiple sclerosis, we undertook a double-blind, randomized, controlled study involving 61 patients. There was a marked improvement in both groups in the course of the study, but no difference between them in either the rate of recovery or the final outcome. High-dose IV methylprednisolone is a safe alternative to ACTH in the management of acute relapse in MS.

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.

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.

Sarcoidosis presenting with stroke

A 25-year-old black man with sarcoidosis presented with transient ischemic attacks followed by sudden, persistent right hemiparesis. He gave a history of recent, recurrent lower motor neuron facial palsy. Computed tomography demonstrated an infarct in the left internal capsule. Chest x-ray film showed bilateral hilar and mediastinal lymphadenopathy and multiple opacities in the lung fields. Serum angiotensin converting enzyme concentration was raised, and a Kveim test was positive for sarcoidosis. Despite clear pathologic reports of cerebral vasculitis in neurosarcoidosis, the occurrence of stroke is extremely rare.

Patterns of selective involvement of thigh muscles in neuromuscular disease

In 14 patients with limb girdle muscular dystrophy, polymyositis, and type 3 spinal muscular atrophy, CT scans of the thigh muscles were correlated with single fiber EMG studies in vastus lateralis, semimembranosus and biceps femoris muscles. There was a relation between the extent of CT scan abnormality and increased fiber density in the three muscles studied, except in the most severely affected muscles in which in some muscles the fiber density values were lower than expected. These results were independent of the underlying pathology. Correlative CT/SFEMG studies provide insights into the pattern of selective involvement of certain muscles in neuromuscular disorders.

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.

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.

Ubiquitin deposits in anterior horn cells in motor neurone disease

A polyclonal antiserum to ubiquitin, a low molecular weight protein involved in the ATP-dependent removal of abnormal cytoplasmic proteins, has been used to stain spinal cord from 10 cases of motor neurone disease and from 12 control spinal cords. All 10 cases of motor neurone disease exhibited antiubiquitin-immunoreactive deposits in a proportion of the surviving anterior horn cells but these deposits were not seen in any of the 12 controls. These ubiquitin deposits do not correspond to previously described neuronal inclusions in motor neurone disease. The ubiquitin deposits represent, therefore, a new neuronal inclusion which possibly reflects previously unrecognised degradative events occurring in the vulnerable neurones.

Increase in pudendal nerve terminal motor latency with defaecation straining

The relationship between perineal descent and pudendal nerve damage was tested in 57 consecutive patients by measuring the left and right pudendal nerve terminal motor latency (PNTML) before and after a maximal defaecation straining effort. In 13 patients the PNTML was also measured 1 and 4 min later. The difference between the mean PNTML before and after straining (delta PNTML) was correlated with the amount of descent (r = 0.40, P less than 0.005), and with the perineal position during straining (r = -0.46, P less than 0.001). Four minutes after the straining effort the PNTML again approached the resting value in each subject. These findings support the concept that perineal descent causes pudendal nerve damage.

Neurologic cause of idiopathic incontinence

The relationship between the pudendal and perineal nerve terminal motor latencies and descent (weakness) of the perineum on straining was investigated in 31 patients with idiopathic fecal incontinence, and in 30 patients with double incontinence. Pelvic floor descent was correlated with increased pudendal nerve terminal motor latency in both groups of patients. In the patients with double incontinence, there was a less significant correlation between perineal descent and increased perineal nerve terminal motor latency. In the patients with fecal incontinence, but without urinary incontinence, there was no correlation between perineal descent and perineal nerve terminal motor latency. These data support the concept that pelvic floor weakness can result in damage to the pudendal and perineal nerves, leading to fecal and urinary incontinence. In patients with isolated fecal incontinence the perineal nerves are relatively spared. Thus these common types of incontinence probably have a neurologic cause, and neurophysiologic methods can be used in their assessment.

Internal anal sphincter in neurogenic fecal incontinence

In neurogenic fecal incontinence there is denervation of the external anal sphincter and pelvic floor muscles but the role of the internal anal sphincter is incompletely understood. We have evaluated the internal anal sphincter in 6 patients with neurogenic incontinence undergoing postanal repair and in 7 control subjects. All the incontinent subjects, but none of the controls, had evidence of pudendal neuropathy. Surface electromyography studies of the internal anal sphincter showed absence of electrical activity in 4 of 6 incontinent subjects; in the remaining 2 subjects and in 6 of 7 controls normal slow waves were present. Internal sphincter muscle strips from control subjects showed normal in vitro responses to noradrenaline, isoprenaline, dimethyl-phenylpiperazinium, and electrical field stimulation; muscle strips from the incontinent patients showed complete insensitivity except in 2 patients in whom there was contraction to noradrenaline and relaxation to isoprenaline. Electron microscopy showed normal smooth muscle in 5 control subjects and minor changes in 1 subject; all the incontinent patients showed abnormalities in the smooth muscle cells of the internal anal sphincter. These findings indicate that in neurogenic fecal incontinence neurogenic weakness of the external anal sphincter and pelvic floor muscles is associated with damage to the internal anal sphincter.

Distal myopathy with focal granular degenerative change in vacuolated type 2 fibers

A slowly progressive distal myopathy with raised blood (CK) level commencing in the second decade was associated with large vacuoles found only in type 2 fibers. The vacuoles consisted of sarcoplasmic spaces without limiting membranes, containing granular and fibrillar material. This material probably represented degenerative products derived from myofibrils. A distinction is drawn between these degenerative vacuolar changes and those reported in other cases of sporadic or hereditary distal myopathy in which autophagic vacuoles are characteristic.

Asymmetrical pudendal nerve damage in pelvic floor disorders

Differences in the left and right pudendal nerve terminal motor latencies have been observed in patients with pelvic floor disorders. Until now the mean value of the left and right pudendal latencies has been used as the index of pudendal neuropathy. In 22 patients of a group of 156 patients studied the pudendal nerve terminal motor latency was abnormally raised on one side only. These patients are thought to have pudendal neuropathy whether or not the mean value of the left and right pudendal latencies is also raised. This observation may have therapeutic implications.

Delayed external sphincter repair for obstetric tear

In some patients with faecal incontinence due to an obstetric tear of the external and sphincter there is additional weakness of the anal sphincter muscles from damage to the innervation of these muscles during delivery. Of 19 patients who required surgical repair of an obstetric sphincter tear some months or years after injury, 9 (47 per cent) had evidence of pudendal nerve damage at pre-operative anorectal physiological investigation. The result of surgical repair was excellent or good in eight of the ten patients in whom there was no evidence of nerve damage, while this was the case in only one of the nine patients with nerve damage. These results are significantly different (P = 0.018). Thus the functional result of delayed anal sphincter repair after obstetric lesions is partly dependent upon whether the nerve supply is intact. Pre-operative physiological evaluation can give information on the probability of a successful surgical result.

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.

Jitter correction: a computer algorithm for reduction of the velocity recovery function artifact

The measurement of neuromuscular jitter in single fiber electromyography may be artifactually raised by a component of interdischarge interval (IDI)-dependent jitter caused by the velocity recovery function (VRF) in muscle fibers. We have developed a computer algorithm for on-line mathematical correction for this artifact, thus improving the reliability of neuromuscular jitter estimates. The method, based on a modeling technique, was validated using intramuscular stimulation in order to either exclude an IDI-dependent component (using regular stimulation) or to include an IDI-dependent component (using pseudorandom stimulation). In 10 normal subjects the distribution of 106 corrected jitter values obtained using voluntary activity showed no difference from the measured values. This finding implies that previously published values for normal jitter are not likely to have been influenced by the VRF effect.

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.