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Biomedical subjects

A Danek

Publications and source records attributed to A Danek.

At least 19 recordsLinked to original sources
PubMed2007

Neurologic phenotypes associated with acanthocytosis.

The term "neuroacanthocytosis" is normally used to refer to autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome, but there are other movement disorders in which erythrocyte acanthocytosis may also be seen, such as Huntington disease-like 2 and pantothenate kinase-associated neurodegeneration. Disorders of serum lipoproteins such as Bassen-Kornzweig disease form a distinct group of neuroacanthocytosis syndromes in which ataxia is observed, but movement disorders are not seen. Genetic testing has enabled us to distinguish between these disorders, even when there are considerable similarities between phenotypes. Improved detection is important for accurate genetic counseling, for monitoring for complications, and, it is hoped, for implementing causal treatments, once these become available. As in other neurodegenerative conditions, animal models are a promising strategy for the development of such therapies.

Acanthocytes↗
PubMed2007

["Hypermetamorphosis". Heinrich Neumann's (1814-1884) legacy].

The term "hypermetamorphosis" was originally coined in 1859 by an almost forgotten psychiatrist from Breslau, now Wroclaw in Poland, Heinrich Wilhelm Neumann. The 1906 textbook of his assistant Wernicke transmitted the concept to Klüver and Bucy, who understood it as the "excessive tendency to take notice of and to attend and react to every visual stimulus" in their syndrome description of bitemporal lobectomy in the monkey (1937-1939). Hypermetamorphosis so far has not been properly operationalized, and the concept appears outdated. Components such as "compulsive manipulation", "magnet reaction/groping", "compulsive grasping/grasp reflex", "utilization behavior", and "environmental dependency syndrome" can be better delineated and are commonly seen in frontal rather than temporal lesions. They may occur with frontal contusion, anterior cerebral artery infarction, in diseases of the Pick complex, and basal ganglia neurodegeneration.

History, 19th Century↗
PubMed2006

[Complexities of "reversible posterior leukoencephalopathy syndrome"].

We report a case of reversible posterior leukoencephalopathy syndrome in a 50-year-old patient with severe untreated hypertension. Recent advances in magnetic resonance imaging (especially diffusion-weighted imaging) allow new pathopysiological insight: it was found that the resulting vasogenic edema was restricted neither to the posterior vascular territories nor to white matter. The apparent diffusion coefficient helps to differentiate between reversible vasogenic edema and cytotoxic edema, the latter indicating irreversible neuronal death.

Antihypertensive Agents↗
PubMed2005

Quantitative evaluation of mirror movements in adults with focal brain lesions.

Mirror movements (MM), involuntary movements of homologous muscles opposite to unilateral limb activity, decrease in the course of motor development, but may reappear in adults after brain damage. To better characterize this type of acquired MM, grip forces of 36 healthy subjects and 35 patients suffering from focal brain lesions were compared. Holding force transducers in a pinch grip between thumb and index fingers of each hand, subjects had to repeatedly change the grip force in one hand, whilst the other (mirror) hand just had to prevent the manipulandum from dropping. In a second task, force changes had to be produced either in a symmetric or in an antiparallel manner. No significant group differences between patients and controls in the extent of coupling were found. During unimanual squeezing, only six patients had a co-activation in the pathologic range. Whilst performing bimanual asymmetric grip force changes, pathologic coupling was seen only in five patients. No association was found between the presence of pathologic MM and clinical or neuroanatomical features. Brain lesions in adults seem only rarely to be associated with pathologic MM. They might be non-specific and not related to the characteristics of the lesion.

Adolescent↗
PubMed2004

[On the vestiges of Heinrich Frenkel (1860-1931)--Pioneer of neurorehabilitation. Annotation to the cover picture].

Heinrich Simon Frenkel or Frenkel-Heiden(1860-1931) is almost completely forgotten as a founder of neurorehabilitation and little is known about his life. Frenkel's main contribution, "The treatment of tabetic ataxia by meansof systematic exercise: An exposition of the principles and practice of compensatory movement treatment", was reprinted several times in English (1902, 1905, 1917). Frenkel exerted great influence among his contemporaries, including his direct student Otfrid Foerster (1873-1941) who became one of the most important neurologists and neurosurgeons of the 20th century. A floor mosaic, preserved in the historic building of the "Medizinische Poliklinik" in Munich, is an exact copy of the pattern of traces that Frenkel had published in 1900 for proprioceptive gait exercises in tabes dorsalis.

Germany↗
PubMed2004

[Oskar Vogt (1870-1959). Hypnotist and brain researcher, husband of Cecile Vogt (1875-1962)].

Oskar Vogt (1870-1955) and his wife Cecile (1875-1962) were neurologists and neuroanatomists with a strong interest in the cytoarchitectonics and myeloarchitectonics of the brain and in the functional anatomy of the basal ganglia. In the 1920s, Vogt created a multi-disciplinary brain research institute, the Kaiser-Wilhelm-Institut fur Hirnforschung in Berlin-Buch, with divisions for e.g. neuroanatomy, neurohistology, neurophysiology, neurochemistry, and genetics. Oskar Vogt's scientific activities are discussed briefly with special regard to his former co-worker Brodmann. After being dismissed from office by the Nazi government in 1937, the Vogts continued their work in a privately funded institute in Neustadt, in the Black Forest.

Biomedical Research↗
PubMed2003

[Cognitive impairment in adults with neurofibromatosis type 1].

Cognitive impairment is a common phenomenon in children with neurofibromatosis type 1 (NF1), but only little is known about its nature and frequency in adult NF1-patients. Using a comprehensive psychometric test battery, we investigated 20 patients with NF1 and 20 age and gender matched control subjects without neurological diseases. Results showed slightly lowered test scores in patients compared with controls but no specific intellectual impairment. On a computerized test of selective attention, the NF1-group had significant slower reaction times. Also, three out of four memory tests and a test of visuoconstructive abilities showed poorer test results in the NF1-patients. Executive functions however were not affected. The findings agreed well with the test profile in NF1-children and supported the idea of a continuum between childhood and adulthood. Observations are discussed in the context of studies investigating the association of cognitive deficits with either intracranial lesions or alterations in the neurofibromin expression.

Adult↗
PubMed2002

[Progress in molecular chorea diagnosis. McLeod syndrome and chorea acanthocytosis].

McLeod syndrome and chorea-acanthocytosis are classified with the so-called neuroacanthocytosis group of syndromes. Both lead to progressive basal ganglia degeneration and were not easily distinguished in the past. With the discovery of their molecular bases, mutations of the X-linked gene XK and autosomal recessive mutations of the gene coding for chorein, respectively, the two phenotypes can now be differentiated and extend the diagnostic spectrum in patients presenting with chorea. The present review compares the two conditions and proposes a practical approach to diagnosis and treatment. Better-defined disease concepts should eventually replace the umbrella term of "neuroacanthocytosis." Animal models are needed to understand the underlying mechanisms. A final common pathway is likely for the pathogenesis of these conditions and is most probably shared with Huntington's disease.

Amino Acid Transport Systems, Neutral↗
PubMed2002

Mutational spectrum of the CHAC gene in patients with chorea-acanthocytosis.

Chorea-acanthocytosis (ChAc) is an autosomal recessive neurological disorder whose characteristic features include hyperkinetic movements and abnormal red blood cell morphology. Mutations in the CHAC gene on 9q21 were recently found to cause chorea-acanthocytosis. CHAC encodes a large, novel protein with a yeast homologue implicated in protein sorting. In this study, all 73 exons plus flanking intronic sequence in CHAC were screened for mutations by denaturing high-performance liquid chromatography in 43 probands with ChAc. We identified 57 different mutations, 54 of which have not previously been reported, in 39 probands. The novel mutations comprise 15 nonsense, 22 insertion/deletion, 15 splice-site and two missense mutations and are distributed throughout the CHAC gene. Three mutations were found in multiple families within this or our previous study. The preponderance of mutations that are predicted to cause absence of gene product is consistent with the recessive inheritance of this disease. The high proportion of splice-site mutations found is probably a reflection of the large number of exons that comprise the CHAC gene. The CHAC protein product, chorein, appears to have a certain tolerance to amino-acid substitutions since only two out of nine substitutions described here appear to be pathogenic.

Chorea↗
PubMed2001

McLeod neuroacanthocytosis: genotype and phenotype.

McLeod syndrome is caused by mutations of XK, an X-chromosomal gene of unknown function. Originally defined as a peculiar Kell blood group variant, the disease affects multiple organs, including the nervous system, but is certainly underdiagnosed. We analyzed the mutations and clinical findings of 22 affected men, aged 27 to 72 years. Fifteen different XK mutations were found, nine of which were novel, including the one of the eponymous case McLeod. Their common result is predicted absence or truncation of the XK protein. All patients showed elevated levels of muscle creatine phosphokinase, but clinical myopathy was less common. A peripheral neuropathy with areflexia was found in all but 2 patients. The central nervous system was affected in 15 patients, as obvious from the occurrence of seizures, cognitive impairment, psychopathology, and choreatic movements. Neuroimaging emphasized the particular involvement of the basal ganglia, which was also detected in 1 asymptomatic young patient. Most features develop with age, mainly after the fourth decade. The resemblance of McLeod syndrome with Huntington's disease and with autosomal recessive chorea-acanthocytosis suggests that the corresponding proteins--XK, huntingtin, and chorein--might belong to a common pathway, the dysfunction of which causes degeneration of the basal ganglia.

Adult↗
PubMed2001

The chorea of McLeod syndrome.

Among the movement disorders associated with acanthocytosis, McLeod syndrome (McKusick 314850) is the one that is best characterized on the molecular level. Its defining feature is low reactivity of Kell erythrocyte antigens. This is due to absence of membrane protein KX that forms a complex with the Kell protein. KX is coded for by the XK gene on the X-chromosome. We present six males (aged 29 to 60 years), with proven XK mutations, to discuss the chorea associated with McLeod syndrome. The movement disorder commonly develops in the fifth decade and is progressive. It affects the limbs, the trunk and the face. In addition to facial grimacing, involuntary vocalization can be present. In early stages there may only be some restlessness or slight involuntary distal movements of ankles and fingers. Lip-biting and facial tics seem more common in autosomal recessive choreoacanthocytosis linked to chromosome 9. This, together with the absence of dysphagia in McLeod syndrome, may help in differential diagnosis. Recent findings suggest a role for the endothelin system of the striatum in the pathogenesis of McLeod syndrome.

Adult↗
PubMed2001

[Type I neurofibromatosis. A model for the study of molecular principles of cognition].

Cognitive impairment in neurofibromatosis type I (NF1) has only recently attracted interest. In addition to previous studies in children, our own investigation of 20 patients confirms the slightly lowered psychometric test scores also for adults with NF1. Molecular manipulation of the neurofibromin gene leads to learning disorders in the mouse model ("cognitive neurogenetics"). It is not just faulty brain development that underlies these findings: neurofibromin plays a role in signal transduction cascades that are active during learning and memory throughout the life span. Thus, it appears possible to cure the cognitive defects at least in the mouse ("cognitive enhancement"). In man, an early diagnosis of NF1 is presently essential in order to provide specific remedial education for children affected by the learning disorder of neurofibromatosis type I.

Adult↗
PubMed2001

A conserved sorting-associated protein is mutant in chorea-acanthocytosis.

Chorea-acanthocytosis (CHAC, MIM 200150) is an autosomal recessive neurodegenerative disorder characterized by the gradual onset of hyperkinetic movements and abnormal erythrocyte morphology (acanthocytosis). Neurological findings closely resemble those observed in Huntington disease. We identified a gene in the CHAC critical region and found 16 different mutations in individuals with chorea-acanthocytosis. CHAC encodes an evolutionarily conserved protein that is probably involved in protein sorting.

Alternative Splicing↗
PubMed2001

Reduction of striatal glucose metabolism in McLeod choreoacanthocytosis.

McLeod syndrome is a distinct form of neuroacanthocytosis. Its defining feature is the depression of erythrocyte Kell antigens. The underlying X chromosomal mutations cause a dysfunction of an erythrocyte membrane protein Kx. A choreatic movement disorder with caudate atrophy in CT and MRI has been reported in McLeod syndrome later in the course of the disease. Positron emission tomography with 18F-deoxyglucose (FDG) was performed in two unrelated affected men. In the older patient, progressive chorea was seen from the 5th decade. In the second patient there were no signs of a movement disorder at the age of 28. Positron emission tomography disclosed a reduction of the striatal FDG uptake in both patients, with accentuation in patient 1. Frontal lobe metabolism was not affected. Basal ganglia dysfunction with early impairment of striatal glucose metabolism thus seems obligatory for McLeod syndrome, as found in other forms of chorea with or without acanthocytosis.

Adolescent↗
PubMed2000

Primary diffuse leptomeningeal gliomatosis: unusual MRI with non-enhancing nodular lesions on the cerebellar surface and spinal leptomeningeal enhancement.

A 28 year old man presented with a 1 month history of symptoms of intracranial hypertension. Examination showed bilateral papilloedema and meningeal signs. Magnetic resonance imaging showed nodular lesions on the cerebellar and pontine surface and thickening of the thoracic spinal leptomeninges. Throughout the course of the disease, contrast enhancement was detected in the spinal leptomeninges but not intracranially. Primary diffuse leptomeningeal gliomatosis (PDLG) was diagnosed by biopsy and later confirmed on necropsy. The present case is remarkable for the nodular superficial cerebellar lesions and the absence of intracranial contrast enhancement of the leptomeninges.

Adult↗
PubMed1999

Dipole source analysis in persistent mirror movements.

To elucidate the pathomechanism underlying persistent mirror movements (MM), we modelled the origin of electric brain activity associated with these movements. Movement-related cortical potentials (MRCP) in a group of subjects affected by persistent mirror movements were compared with those of a control group. The data of the normal subjects were best explained with two bilaterally active electric sources in the sensorimotor cortices with a clear preponderance of the hemisphere contralateral to the movement. In contrast, the MM subjects presented a fairly symmetric source activity in both hemispheres during unilateral intended movements. In the control group, the source representing the activity of the motor cortex ipsilateral to the moving finger reduced activity before the beginning of the movement; this was interpreted as an inhibition of the ipsilateral motor cortex during unilateral movement. In the MM group, however, this inhibition was not seen. Furthermore, while normal subjects demonstrated no relevant activity of an additional source placed near midline motor structures (supplementary motor area; SMA), subjects with MM showed considerable activity of this dipole source. These findings suggest that subjects with persistent MM have abnormal bilateral activation of the primary motor areas, probably together with an additional activation of mesial motor structures. This assumption fits well with the observation of an incomplete decussation of the pyramidal tract. The bilateral activation is then explained as a compensatory strategy in order to achieve sufficient force in the innervated target muscles.

Adolescent↗