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Biomedical subjects

A R Wintzen

Publications and source records attributed to A R Wintzen.

At least 19 recordsLinked to original sources
PubMed1995

Acquired neuromyotonia: evidence for autoantibodies directed against K+ channels of peripheral nerves.

Acquired neuromyotonia is characterized by hyperexcitability of motor nerves leading to muscle twitching, cramps, and weakness. The symptoms may improve following plasma exchange, and injection of immunoglobulin G (IgG) from 1 neuromyotonia patient into mice increased the resistance of neuromuscular transmission to d-tubocurarine. Here we examine nerves and muscle in vitro from mice injected with plasma or purified IgG from 6 neuromyotonia patients or pooled control subjects, and cultured dorsal root ganglion cells after treatment with IgG. Three of the patients had antibodies against human voltage-gated potassium channels labeled with 125I-alpha-dendrotoxin. The quantal release of acetylcholine (quantal content) at end-plates in diaphragms from mice treated with neuromyotonia IgG preparations was increased by 21% relative to control values (p = 0.0053). With one IgG preparation, the duration of the superficial peroneal nerve compound action currents was increased by 93%. The dorsal root ganglion cells treated with this IgG showed a marked increase in repetitive firing of action potentials. All effects were similar to those obtained with aminopyridines. We conclude that at least some patients with acquired neuromyotonia have antibodies directed against aminopyridine- or alpha-dendrotoxin-sensitive K+ channels in motor and sensory neurons, and they are likely to be implicated in the disease process.

4-Aminopyridine↗
PubMed1992

Inclusion body myositis: its relative frequency in elderly people.

Inclusion body myositis (IBM) is a distinct, steroid resistant, form of inflammatory myopathy. Its recognition is the more important because of the preponderant occurrence in the elderly, in whom steroid treatment is hazardous. Since the relative frequency of IBM among inflammatory myopathies in the elderly is undetermined, we retrospectively studied its frequency among all our patients over 50 years, diagnosed between 1980 and 1991 with inflammatory myopathy. Nine of 15 patients with inflammatory myopathy appeared to suffer from IBM. In a further 2 patients this diagnosis was strongly suspected. We conclude that IBM is the most frequent inflammatory myopathy in the elderly. This observation warrants restraint with steroids in the management of inflammatory myopathy in the elderly.

Aged↗
PubMed1992

Muscle fiber conduction velocity in the diagnosis of sporadic hypokalemic periodic paralysis.

A 6-year-old girl presented with episodes of profound muscle weakness since the age of 2 years. On the basis of decreased ictal serum potassium level and lack of metabolic disorder, primary hypokalemic periodic paralysis (HPP) was diagnosed. Both parents and 3 sibs were unaffected clinically. In all of them asymptomatic heterozygosity was very unlikely by the finding of normal muscle fiber conduction velocities, whereas in the patient interictal muscle fiber conduction velocity was lowered. Determination of muscle fiber conduction velocity can be helpful in documenting sporadic occurrence of HPP.

Child↗
PubMed1992

Eye movements in myotonic dystrophy.

Smooth pursuit eye movements were studied with infrared reflection equipment in 10 patients with myotonic dystrophy and in 10 age- and sex-matched controls. Smooth pursuit gain, measured after correction for catch-up saccades, was decreased in the patient group. Normal latencies of saccadic eye movements made a lack of attention an unlikely explanation for this low gain. Likewise, presence of catch-up saccades and normal fixation made it unlikely that extra-ocular myopathy explained the low smooth pursuit gain. We suggest that periventricular white matter abnormalities represent a more likely explanation.

Adult↗
PubMed1991

Postinfectious encephalitis in two siblings.

A 33-year-old man and his 32-year-old sister developed, with an interval of 2 years, an acute fatal encephalitis following an upper respiratory tract infection of unknown etiology. Autopsy documented postinfectious encephalitis in both. This is the first report of postinfectious encephalitis occurring in first degree relatives, suggesting that specific genetic factors play a role in the pathogenesis of this disease.

Adult↗
PubMed1991

Assessment of autonomic function in myotonic dystrophy.

Published reports suggested autonomic nervous system dysfunction in myotonic dystrophy but were inconclusive partly due to small patient numbers and because only a limited number of tests was used. Autonomic nervous system function with noninvasive tests was assessed in ten myotonic dystrophy patients and age and sex matched healthy controls. Statistically significant differences included reduction in the heart rate response to standing and in the blood pressure response to sustained handgrip. Latency of the pupillary light reflex was not different from controls but the time to reach peak velocity of contraction was significantly longer in the myotonic dystrophy group. It is argued that these results reflect dysfunction of voluntary and iris smooth muscle rather than autonomic nervous system dysfunction.

Adult↗
PubMed1989

Effects of a high-protein diet in acid maltase deficiency.

The effects of a high-protein diet were studied in 5 adult cases of acid maltase deficiency. Measurements of muscle strength, pulmonary function and 3-methylhistidine excretion revealed no improvement consistently attributable to the diet.

Dietary Proteins↗
PubMed1988

Linkage studies in facioscapulohumeral muscular dystrophy.

Possible linkage between the locus for autosomal dominant facioscapulo-humeral muscular dystrophy and the locus for the constant region of the heavy chains of the IgG immunoglobulins (Gm) was tested in 1 kindred (23 affected and 18 unaffected sibs) using the polymorphic DNA probe D14S1, which is known to be closely linked with Gm. No linkage between the loci for the disease and the probe was found, and the lod scores suggested that the locus for facioscapulohumeral muscular dystrophy is not situated on the distal part of the long arm of chromosome 14.

Chromosome Mapping↗
PubMed1988

Haemorrhagic necrosis of the grey matter of the spinal cord due to accidental injection of iopamidol in a patient with multiple neurofibromas; a clinico-pathological study.

Cervical laminectomy was performed in a 34-year-old man with multiple spinal neurofibromas because of a slowly progressive medullary compression. Four weeks later a rapid deterioration necessitated iopamidol myelography by left lateral cervical puncture at C2 level. Despite the establishment of adequate spinal fluid contact, resulting in imaging of the subarachnoid space, part of the contrast medium entered the spinal cord, thus delineating a syrinx from the upper cervical extending to the upper thoracic level. After the puncture the patient developed triplegia, involving the left arm and both legs and a paresis of the right arm. He died from aspiration pneumonia. Autopsy revealed haemorrhagic necrosis of the spinal grey matter. This adverse effect of myelography is argued to have been conditioned by the extreme immobility and displacement of the spinal cord due to the presence of multiple neurofibromas. The deterioration four weeks after the operation was probably caused by a further compression of the spinal cord.

Adult↗
PubMed1988

Dysphagia in inclusion body myositis.

Four elderly patients with inclusion body myositis and dysphagia are described. Dysphagia was the presenting symptom in three, preceding generalised weakness by 1.5 to 7 years. Myotomy of the cricopharyngeal muscle improved the symptoms and signs in 3 of the 4 patients. It is suggested that inclusion body myositis is not an infrequent cause of dysphagia in elderly people, and is amenable to treatment.

Aged↗
PubMed1988

Cerebral venous thrombosis as presenting sign of myeloproliferative disorders.

Two patients with cerebral venous thrombosis are described. In both patients laboratory findings suggested an underlying haematological disorder and bone marrow biopsy showed a myeloproliferative disorder. Both chronic cerebral venous thrombosis and early myeloproliferative disorders are difficult to diagnose. Their combined occurrence may be less rare than is frequently supposed.

Adult↗