Biomedical subjects
A Danek
Publications and source records attributed to A Danek.
Geniospasm: hereditary chin trembling.
Geniospasm is a hereditary disorder characterized by episodic, usually stress-induced involuntary trembling of the chin. Nineteen families from Europe and the U.S.A. suffering from this disorder have been described since 1894. We present three cases from two newly detected families. There was no evidence of any other nervous system abnormality, although abnormal EEG, sleep disorders, and involvement of other facial muscles have been described in rare cases. Geniospasm is transmitted as an autosomal-dominant trait with high penetrance. It must be differentiated from facial myokymia, palatal tremor, and essential tremor affecting facial muscles. Neurophysiological and molecular mechanisms of this peculiar disorder are unknown.
Motor recovery following capsular stroke. Role of descending pathways from multiple motor areas.
The functional anatomy of motor recovery was studied by assessing motor function quantitatively in 23 patients following capsular or striatocapsular stroke. While selective basal ganglia lesions (caudate and/or putamen exclusively) did not affect voluntary movements of the extremities, lesions of the anterior (plus caudate/putamen) or posterior limb of the internal capsule led to an initially severe motor impairment followed by excellent recovery, hand function included. In contrast, lesions of the posterior limb of the internal capsule in combination with damage to lateral thalamus compromised motor outcome. In experimental tracing of the topography of the internal capsule in macaque monkeys, we found axons of primary motor cortex passing through the middle third of the posterior limb of the internal capsule. Axons of premotor cortex (dorsolateral and post-arcuate area 6) passed through the capsular genu, and those of supplementary motor area (mesial area 6) through the anterior limb. Small capsular lesion can therefore disrupt the output of functionally and anatomically distinct motor areas selectively. The clinically similar motor deficits with a similar course of functional restitution following disruption of these different descending motor pathways indicate a parallel operation of cortical motor areas. They may have the further capability of substituting each other functionally in the process of recovery from hemiparesis.
The meaning of Sherlock Holmes.
Explore the source record for details and available documents.
Cortically evoked motor responses in patients with Xp22.3-linked Kallmann's syndrome and in female gene carriers.
Patients with Kallmann's syndrome show hypothalamic hypogonadism, hyposmia, and congenital mirror movements. As a correlate, a defect of gonadotropic neuron migration into the brain was recently detected. Considering abnormal outgrowth of neurons also as a possible substrate underlying mirror movements, we studied 3 patients and 2 asymptomatic female gene carriers from a kindred with proven linkage to Xp22.3, using focal transcranial magnetic stimulation of motor cortex hand areas with a figure-eight coil. In all 3 affected brothers, bilateral responses could be evoked almost simultaneously in their thenar muscles (slight latency differences were statistically insignificant). In contrast, the mother and the maternal aunt showed only unilateral, normal thenar responses, even with maximum tolerable stimulator output and high signal amplification. Correspondingly, mirror movements were present in the patients, but not in the gene carriers. Bilaterality of cortically evoked hand muscle responses and mirror movements, therefore, behaved as X-chromosomal recessive traits. A likely cause might be a disorder of neuronal outgrowth in the motor system, particularly of inhibitory callosal fibers. For normal anatomical development of the motor system, one intact Xp22.3 gene seems necessary.
McLeod syndrome: a distinct form of neuroacanthocytosis. Report of two cases and literature review with emphasis on neuromuscular manifestations.
McLeod syndrome was originally described on the basis of a specific blood group phenotype with weak expression of Kell antigens. This erythrocyte abnormality also causes acanthocytosis. The haematological findings are associated with abnormalities in other organ systems, including neuromuscular manifestations. A 51-year-old patient was followed up for 11 years. He presented with persistent muscle creatine kinase elevation and progressive heart disease and later developed a slowly progressive neuropathy and choreic movements. His younger brother presented with grand mal seizures, involuntary movements and high muscle creatine kinase when aged 43 years. Clinical myopathy was absent in both, yet muscle biopsy showed mild myopathic changes. The presence of a motor axonopathy was supported by electrophysiological findings. One brother also showed sensory axonopathy. The movement disorder suggested accompanying basal ganglia dysfunction. Earlier reports of McLeod syndrome are reviewed with respect to neuromuscular involvement. Absence of the Kx membrane protein seems to be the cause of this multi-system disorder.
Motor responses after transcranial electrical stimulation of cerebral hemispheres with a degenerated pyramidal tract.
Motor responses were evoked in the thenar muscles by transcranial electrical cortex stimulation in 5 stroke patients with an isolated lacuna in the internal capsule, in whom wallerian degeneration of the pyramidal tract was demonstrated in vivo. Suprathreshold stimulation of the affected hemisphere elicited bilateral motor responses; whereas, stimulation at identical intensities of the undamaged hemisphere yielded strictly unilateral responses in the contralateral hand, like the responses of all normal control subjects. Focused magnetic brain stimulation was performed in 1 patient and gave identical results. Because muscular excitability to cortical stimulation is preserved in spite of pyramidal tract disruption, other pathways must bypass the lesion. Because of the bilaterality of responses, we suggest polysynaptic corticoreticulospinal connections.
Fibre divergence in the distal optic radiation: possible basis of functional plasticity in adult primate visual cortex.
The precision of retinotopy in primate visual cortex is commonly thought to result from highly ordered arrangement of fibres in the visual pathways. However, rigid point-to-point representation is hardly compatible with findings of a substantial reorganization of visual cortical maps after peripheral and central lesions. Such observations could be accounted for by divergence in the optic radiation. To explore the hypothesis of fibre divergence, we made small knife cuts in the distal optic radiation of macaca fascicularis. After subsequent axonal tracing by injecting WGA-HRP into lateral geniculate nucleus, we studied the course of distal fibres in white matter. The amount of divergence was assessed by measuring, relative to the prevailing fibre course, length and orientation of labelled fibres between lesion and entry into cortex. Lesion sizes between 1 mm to 3 mm did not result in any detectable diminution of terminal labelling in layer IVC of striate cortex. Individual labelled fibres were found to diverge symmetrically from both sides into the gap distal to the lesion. Divergence starts at a distance of about 3 mm before cortex. At the white matter boundary, less than 10% of all fibres still retain the original direction, with the remaining fibres taking any other orientation without preference. We estimate that this corresponds to a divergence of visual afferents encompassing about 6-10 mm of cortical distance, if intracortical arborization of terminal fibres is taken into account. Possible consequences for functional plasticity in the adult primate visual cortex are discussed.
Normal dystrophin in McLeod myopathy.
Dystrophin and its gene were studied in a patient with McLeod syndrome. This X-linked recessive myopathy has been localized to Xp21, as has the Duchenne muscular dystrophy gene locus, which codes for dystrophin. Histopathological study of the patient's muscle showed mild subclinical myopathy. Immunological studies of dystrophin in two separate biopsy specimens and analysis of dystrophin gene DNA from a blood sample did not detect an abnormality. This suggests that the Duchenne muscular dystrophy gene, albeit close to the McLeod locus, is not involved in McLeod myopathy.
Aneurysms and vacuolar degeneration of cerebral arteries in late-onset acid maltase deficiency.
We present a case of late-onset acid maltase deficiency (AMD) with pronounced involvement of the liver and skeletal muscles. In addition, and in contrast to other adult cases of AMD, the case presented here shows CNS pathology with hypodense and hyperintense white matter areas on CT and MRI scans, and myelin changes ranging from focal areas of demyelination to necrosis. Neuropathologic changes seem to be related to unusual vascular pathology consisting of vacuolar degeneration of small and large arterial blood vessels. Vacuoles of varying size, partly filled with granular PAS-positive material, were found in pericytes and smooth muscle cells of arterial vessel walls. Electron microscopy revealed lysosomal and cytoplasmic free glycogen in smooth muscle cells in the intima of large cerebral arteries as well as in pericytes of arterioles and capillaries. Accumulation of glycogen locally was associated with severe cellular damage and necrosis. The formation of a great number of small aneurysms of intracerebral arteries is thought to be the result of cell damage in the vessel walls.
[Striato-nigral degeneration (SND): a multisystem atrophy?].
Two cases of striato-nigral degeneration are reported. In case 1 the female patient showed a Parkinson syndrome, cardiac arrhythmias and vasomotor disturbances. Morphologically mainly the putamen and substantia nigra revealed severe atrophic changes according to the restricted form of striato-nigral degeneration (SND). In case 2 there was a disorder of the upper and lower motor neuron in a female patient. Morphologically this case was an example of a multisystem atrophy with changes in the striato-nigral, olivo-ponto-cerebellar systems and spinal motor and autonomic neurons. These cases demonstrate the variability of the striato-nigral degenerations which are met with in two forms: a "pure" form as in case one and as a part of multisystem atrophies. This is underlined in a review of 69 literature cases, which also shows that SND, Shy-Drager syndrome and olivo-ponto-cerebellar atrophy represent very probably different varieties of one and the same degenerative process.
[Restless legs syndrome. Clinical aspects, differential diagnosis, therapeutic approaches].
Explore the source record for details and available documents.
The dream king's psychiatrist Bernhard von Gudden (1824-1886). A life committed to rationality.
Bernhard von Gudden's life is commemorated as being exemplary for a generation of physicians who in the last century established some of the still valid approaches of modern neuroanatomy, neurology, and psychiatry. His personal contribution to neuroanatomy was the experimental method, major technical advances, and the clarification of the fiber course in the optic chiasm. As a psychiatrist he introduced the humanitarian principle of "no restraint" to German asylums. Although he did not attempt to develop a systematic nosology, he nevertheless founded an influential school of psychiatrists (eg, Forel, Kraepelin, and Nissl). For many years Gudden served as consulting psychiatrist to Bavaria's royal family and drowned together with his patient, King Ludwig II, whose sanity had been questioned.
[Korbinian Brodmann (1868-1918)].
Brodmann, an anatomically orientated neuropsychiatrist, is one of the most influential cortical localizationists. His comparative studies and brain maps are still fundamental for the descriptive anatomy of the cortex. Brodmann made his main contributions while working at the brain research institute of Oskar Vogt in Berlin (1901-1910). Due to unfavourable circumstances he was unable to extend his findings much further. We recount his biography on the basis of new source material, recently collected through a memorial archive in his hometown in south-west Germany. Modern methods have corroborated Brodmann's concept of cortical parcellation into "areae"--although their function is still largely unknown.
[Ataxic hemiparesis: specificity of the vascular territory?].
Explore the source record for details and available documents.
[First-pass effect as a therapeutic problem].
Explore the source record for details and available documents.
Specific binding sites for vasoactive intestinal polypeptide on nonadherent peripheral blood lymphocytes.
Vasoactive intestinal polypeptide (VIP), an octacosapeptide isolated from porcine duodenum and thought to have neuromodulator function in several functional systems (gastrointestinal tract, brain, lung, genital tract, heart), was recently detected in human neutrophils by radioimmunoassay. Subsequent studies demonstrated a VIP-mediated increase in lymphocyte adenylate cyclase. In this paper, VIP binding studies are presented using viable nonadherent human lymphocytes. Binding of 125I-VIP to nylon wool column-purified lymphocytes is specific, time dependent, rapid, and reversible. Bound radioactivity varies linearly with the number of cells used and is displaceable by non-iodinated VIP in a dose-dependent manner with complete displacement between 1 pM and 50 nM. Scatchard analysis of competition experiments demonstrates one class of specific binding sites with a KD of 0.47 +/- 0.23 nM and a Bmax of 24.9 +/- 7.0 pM. This Bmax represents 1700 binding sites/cell. secretin, gastric inhibitory polypeptide, and glucagon did not effectively compete with 125I-VIP for binding sites. This is the first demonstration of VIP receptors in a purified population of human lymphocytes; the data suggest that VIP may modulate lymphocyte function.
[The International System of Units (SI) and its use in medicine].
Explore the source record for details and available documents.