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Biomedical subjects

J N Walton

Publications and source records attributed to J N Walton.

At least 37 records · Page 2Linked to original sources
PubMed1979

Carrier detection in Duchenne muscular dystrophy: Assessment of the effect of age on detection-rate with serum-creatine-kinase-activity.

In 40 known carriers of the gene for Duchenne muscular dystrophy (mean age 38 years) the detection-rate with a standard assay of serum-creatine-kinase was 53%. In 52 daughters of known carriers (mean age 16 years) the detection-rate was 45% after correction of age. This implies a much higher detection-rate (about 90%) in young carriers and suggests that discrimination between carriers and noncarriers may best be achieved by testing in childhood.

Adolescent↗
PubMed1979

An evaluation of some carrier detection techniques in Duchenne muscular dystrophy.

Some recently described abnormalities in the serum and red cell membranes in Duchenne dystrophy have been examined as methods of carrier detection in a single-blind controlled study. Twelve carriers (4 definite, 3 probable and 5 possible carriers previously found to have raised creatine kinase levels) and 12 normal female controls of the same age, were examined on 3 separate occasions at approximately two-weekly intervals. Analysis of age-dependent red cell shape changes, serum haemopexin levels, red cell K+ efflux rate, sensitivity of red cell ghost membrane ATPase to ouabain, membrane protein phosphorylation studies and lactate dehydrogenase isoenzyme profiles on agarose gel electrohoresis all failed to distinquish carriers from controls. The carriers suffered muscle cramps more frequently than the controls and all but one carrier and two control subjects were correctly identified by manual muscle strength testing, certain proximal muscles in paricular being consistently weaker in carriers than in the control group subjects. Scalar electrocardiography revealed higher values for the R/S ratio in Leads V1 and V2 and the sum (R-S) in V2.

Adenosine Triphosphatases↗
PubMed1978

A genetic study of subacute and chronic spinal muscular atrophy in childhood. A nosological analysis of 124 index patients.

A genetic study of the subacute spinal muscular atrophies (SMA) of late infancy and early childhood has been undertaken. All such patients with chronic disease (with ages at onset up to 14 years, and excluding SMA Type I) known to 2 large Neurological Centres were reassessed clinically and genetically. There were 124 index patients (67 females and 57 males) and 17 secondary cases, which formed two consecutive unselected series. To investigate the genetic composition of this group, 4 nosological approaches were used; cluster analysis of clinical features of the disease, Haldane's sib-sib analysis on familial cases, interpretation of frequency distribution histograms, and a segregation analysis. A single autosomal recessive gene accounts for over 90% of cases, causes a clinical syndrome which manifests its first clinical signs before 5 years of age and in almost all cases before two years of age, but which is compatible with life into the third decade. Moderate intrafamilial discordance for some clinical features may be observed, but no genetic heterogeneity within this group was demonstrated. A small group of cases is caused by (a) new dominant mutation(s), or (b) is composed of phenocopies, or both. This relatively uncommon form may comprise the majority of late-presenting cases, and may account for all cases which manifest the first signs after 5 years of age. The spectrum of age-at-onset of this group cannot be determined at present, but the disease may be manifest before the age of two years; it is clinically indistinguishable from SMA caused by an autosomal recessive gene. The literature has been reviewed in the light of these findings. Empirical risks for use in genetic counselling are presented.

Child, Preschool↗
PubMed1978

A clinical and genetic study of spinal muscular atrophy of adult onset: the autosomal recessive form as a discrete disease entity.

A clinical and genetic study of spinal muscular atrophy (SMA) of adult onset is reported. A genetic analysis of all cases of SMA occurring over a ten-year period in North-east England (48 index cases) has shown that chronic proximal SMA of adult onset is a distinct clinical and genetic entity, and is not a variant of the more common and relatively benign late juvenile cases. Nine cases of SMA of adult onset have been studied, occurring in 6 families. The median age of clinical onset was 35 years and the mean age at initial medical presentation was 37 years. The sex ratio was 5:4 (males:females). The condition is relatively benign and there is no evidence to date that life expectancy is shortened; there is usually no premonitory evidence of muscular weakness in early adult life. The muscular involvement is relatively symmetrical and the distal musculature is well preserved; clinical progression of the disease is interrupted by periods of apparent arrest. No patient was able to walk completely unaided twenty years after the initial clinical onset; the median age of patients in the study was 61 years but only one was confined to a wheelchair. In the early stages the recessive form of familial motor neuron disease must be excluded. A segregation analysis of sibs born after index cases was undertaken (segregation ratio of 0.20). This finding is consistent with autosomal recessive inheritance with an extended period during which the disease might initially present. The presence of new dominant mutations cannot be excluded, but is unlikely to account for more than 10% of cases. The carrier rate in the English population is estimated to be 1 in 300, with a gene frequency q = 0.00165. Prevalence is 0.32 per 100,000 in the general population. Empirical risks for genetic counselling are presented.

Adolescent↗
PubMed1977

Spinal cord limb motor neurons in dystrophia myotonica.

The total numbers of limb motor neurons have been counted in 20 micron sections of the lumbosacral spinal cord obtained a autopsy from 5 control subjects who showed no evidence of neuromuscular disease and from 5 patients with dystrophia myotonica ranging in age from 42 to 64 years. No significant reduction in the total number or distribution of such neurons was found in the cases of myotonic dystrophy and the quantity of lipofuscin present in the cells was similar to that in controls. Glial cell numbers were, however, significantly increased in the cases of dystrophia myotonica and this increase was not due to shortening or "crowding" of the relevant cord segments; in 2 patients with dystrophia myotonica the cell body area of the motor neurons was reduced by comparison with normal controls.

Adult↗
PubMed1977

Localised nodular myositis: a clinical and pathological variant of polymyositis.

Three cases of a painful, inflammatory, nodular myopathy in young and middle-aged adult males are described. In two of the cases the nodular process gradually evolved into a diffuse proximal myopathy accompanied by dysphagia, and manifesting the so-called "facioscapulohumeral syndrome". The electromyogram (EMG) in all three cases was "myopathic" in type and in two cases abnormalities consistent with an inflammatory muscle disorder were seen. Muscle biopsy revealed a consistent pattern of intense, predominantly interstitial, pleomorphic infiltration of muscle with scattered foci of muscle fibre destruction and regeneration, which resembled muscle infarcts. It is suggested that this syndrome, whilst readily recognizable from both the clinical and pathological standpoints, is not a nosological entity in its own right but rather an unusual presentation of polymyositis.

Adult↗
PubMed1973

The syndrome of myosclerosis.

Three cases are described presenting with progressive contractures in whom the muscles felt firm and `woody' and a clinical diagnosis of myosclerosis was made in each case. A patient and his young sister were shown to be suffering from spinal muscular atrophy with superimposed, excessive proliferative activity of fibroblasts, and in these cases a beneficial effect of penicillamine was demonstrated. The third case with a clinical picture of myosclerosis was found on muscle biopsy to have extensive inflammatory infiltration of the connective tissue, and responded temporarily at least to high doses of corticosteroids. It is emphasized that several different disease entities can give rise to this clinical picture.

Adult↗