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Biomedical subjects

R J Lane

Publications and source records attributed to R J Lane.

At least 37 records · Page 2Linked to original sources

Difficulties in distinguishing sporadic from familial amyotrophic lateral sclerosis.

Mutations of the copper/zinc superoxide dismutase (SOD-1) gene are present in around 20% of patients with a family history of amyotrophic lateral sclerosis. The finding of these mutations in patients with sporadic amyotrophic lateral sclerosis is rare. We describe a family with amyotrophic lateral sclerosis associated with the SOD-1 mutation Asp 101 Asn. This mutation was previously described as occurring in a patient with sporadic disease. We discuss the difficulties in defining truly sporadic amyotrophic lateral sclerosis, and the consequent implications on the neurogenetic advice given to other family members.

Amyotrophic Lateral Sclerosis↗

Oculomotor function in amyotrophic lateral sclerosis: evidence for frontal impairment.

Saccadic eye movements, fixation, and smooth pursuit were recorded in 17 subjects with amyotrophic lateral sclerosis (ALS) and 11 age-matched controls using a magnetic scleral search coil. Reflexive, remembered and antisaccades, and smooth pursuit at four target velocities were studied. Subjects with ALS showed significantly elevated error rates (distractibility) and latency in the antisaccade and remembered saccade paradigms but no abnormality of reflexive saccades. The frequency of small saccades that intruded on steady fixation (square-wave jerks) was also increased in ALS subjects. Peak velocity gain of smooth pursuit and performance on the Wisconsin Card Sort Test did not differ significantly between the two groups. These findings are consistent with prefrontal dysfunction in ALS and provide an independent source of support for the thesis that the pathology of this condition invades frontal cortex.

Adult↗

Investigation of a null mutation of the CNTF gene in familial amyotrophic lateral sclerosis.

Neurotrophic factors, such as ciliary neurotrophic factor (CNTF), have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), a human neurodegenerative disease primarily of upper and lower motor neurones. A null mutation of the CNTF gene has recently been described. The mutation is an intronic point mutation (G to A) which generates a new splice acceptor site and a 4 bp insertion within the CNTF coding region, and prevents the expression of the normal protein. We investigated this as a candidate gene in 49 families with ALS, where the genetic component may be expected to be strongest. 65% were normal homozygotes, and 35% were heterozygotes for the mutation. No mutant homozygotes were detected. The absence of CNTF protein expression associated with the homozygote mutation does not appear to be of major significance in the development of ALS.

Adult↗

Myopathy in acquired partial lipodystrophy.

We describe two women with acquired partial lipodystrophy, one with significant myopathic symptoms and signs. Muscle biopsy of deltoid and quadriceps was performed in each case. The light microscopy findings were of type 1 and type 2 fibre hypertrophy, with an increase in intracytoplasmic fat in both cases. Electron microscopy showed normal fibres, with accumulations of electron-lucent fat droplets between the myofibrils. The cause of the lipodystrophies is uncertain, but myopathy may be a feature, and muscle biopsy studies may help in further defining the syndrome.

Adipose Tissue↗

Familial amyotrophic lateral sclerosis with a point mutation of SOD-1: intrafamilial heterogeneity of disease duration associated with neurofibrillary tangles.

Mutations of SOD-1 have recently been associated with autosomal dominant familial amyotrophic lateral sclerosis (ALS). A patient is described with a 20 year duration of motor neuron disease, with clinical features of ALS, who was heterozygous for a point mutation ATT to ACT leading to substitution of isoleucine for threonine at codon 113 in exon 4 of SOD-1. This mutation has previously been described in two families with ALS and three apparently sporadic cases of ALS. The patient described here had a family history suggestive of autosomal dominant inheritance of this genetic mutation; other members of the family having a more typical disease duration. Unusual pathological features included neurofibrillary tangles in neurons of the globus pallidus, substantia nigra, locus coeruleus, and inferior olivary nuclei, and absence of ubiquitin immunoreactive inclusions in motor neurons. This may reflect the slow progression of the neurodegeneration associated with the SOD-1 mutation in this patient. The prolonged survival, of over 20 years, with other family members having a more typical survival of two to three years, has important implications for genetic counselling in families with ALS in addition to the fundamental biological questions concerning the influence of these mutations on disease expression.

Amyotrophic Lateral Sclerosis↗

Testosterone deficiency myopathy.

Testosterone is recognized to have a positive effect on nitrogen balance and muscle development in hypogonadal men, but significantly myopathy secondary to testosterone deficiency has been reported only rarely. We describe a patient who presented with a myopathy associated with testosterone deficiency, and who demonstrated a significant functional and myometric response to treatment.

Aged↗

The influence of graft type on patency of infrainguinal arterial bypass grafts.

Between 1985 and 1992, 328 patients underwent 392 infrainguinal reconstructions. Indications for operation were disabling claudication in 126 patients, critical limb ischemia in 246 and uncomplicated popliteal aneurysm in 20. Grafts were to the above knee popliteal artery in 134 patients, below knee popliteal artery in 176 and infrapopliteal ("distal") in 82 patients. Graft types included 160 reversed saphenous vein (RSV), 95 polytetrafluoroethylene (PTFE), 84 nonreversed saphenous vein (NRSV), 41 composite grafts (PTFE plus vein) and 12 others. Results show the five year patency rate for all grafts of 58 percent and limb salvage (for limb ischemia) of 74 percent. Above knee and below knee popliteal grafts (three year patency rates of 72 and 66 percent) performed significantly better than distal grafts (51 percent three year patency rate, p < 0.025). NRSV grafts comprised 63 ex situ ("translocated") and 21 in situ grafts. No significant difference was shown between these (two year patency rates of 62 and 65 percent). There was no significant difference between RSV and NRSV grafts in this series, although RSV tended to show higher patency rates. Composite grafts (below knee, three year patency rate of 45 percent) had significantly lower three year patency rates than below knee RSV (79 percent, p < 0.005). RSV remains the conduit of choice in this unit, with long term patency comparable with other published series. Use of NRSV (translocated and in situ) allows increased use of autogenous vein with the associated higher patency rates compared with prosthetic materials and is the graft of choice if the long saphenous vein is not suitable for use in the standard reversed method. The translocated technique allows more flexibility in the use of nonreversed vein with results comparable with the in situ technique. Composite grafts provide a useful alternative to PTFE alone for infrageniculate grafting when insufficient autogenenous vein is available.

Adult↗

Myopathy in HIV infection: the role of zidovudine and the significance of tubuloreticular inclusions.

Muscle biopsies were obtained from 33 consecutive HIV-infected patients with symptoms suggestive of muscle disorder. Twenty-three patients had clinical evidence of myopathy; 18 of these had been taking zidovudine (AZT) for between 8 and 28 months, and were found to have a multifocal necrotizing myopathy with little or no inflammation. However, the remaining five clinically myopathic patients, who had never received AZT or had stopped treatment at least 5 months earlier, had either a necrotizing myopathy which appeared indistinguishable for that seen in patients taking the drug, or an inflammatory myopathy. The 10 clinically non-myopathic patients showed no significant histological abnormalities. Tubuloreticular inclusions (TRI), in capillary endothelial cells, were found in all clinically myopathic cases but were not seen in five out of ten clinically non-myopathic cases. We suggest that AZT causes a myopathy only when an underlying HIV-related inflammatory myopathy is present. The drug appears to substantially reduce the inflammatory reaction in the muscle, but this may recur when the drug is stopped. The appearance of TRI may be the first manifestation of HIV activity in muscle.

Adult↗

Persistence of enterovirus RNA in muscle biopsy samples suggests that some cases of chronic fatigue syndrome result from a previous, inflammatory viral myopathy.

Molecular hybridization using an enterovirus group specific probe detected virus RNA in muscle biopsy samples from 25 of 96 cases of inflammatory muscle disease and similarly from 41 of 158 cases of postviral fatigue syndrome (PFS). Enterovirus RNA was detected in only two of 152 samples of control muscle. The inflammatory myopathy group comprised patients with polymyositis (PM), juvenile dermatomyositis (JDM) or adult dermatomyositis (DM), and all showed the presence of an inflammatory infiltrate and fiber necrosis on histological examination of a muscle biopsy sample. In contrast, muscle samples from the PFS group were histologically normal except for non-specific changes such as occasional single fiber atrophy. By analogy with enteroviral myocarditis, which can progress to a post-inflammatory disease with persistence of virus in myocardium and disposes to the rapid development of dilated cardiomyopathy, we propose that PFS syndrome may be a sequela of a previous inflammatory viral myopathy.

Biopsy↗