Nerve compression syndromes in ALS: a retrospective analysis in 554 patients.

We retrospectively screened a large cohort of 554 ALS patients with regard to documented nerve compression syndromes and identified 23 patients, mostly with carpal tunnel syndrome. Patients could be subdivided into three groups. Group A comprised 13 patients in whom nerve compression was apparently confused with early ALS signs. Group B consisted of six patients diagnosed with carpal tunnel syndrome who had experienced improvement after surgery years before they eventually developed ALS. Group C consisted of four patients who, after diagnosis of ALS, additionally developed a nerve compression syndrome. Altogether, the frequency of true nerve compression syndromes in our ALS cohort (1.8%) was no higher than in the general population (0.3-10.8%). In group A, the initial confusion with a nerve compression syndrome led to a slight though not significant delay (15.2 vs. 12.9 months; p = 0.32) of the diagnosis of ALS. Survival was no different between group A and the cohort. It can also be concluded that the misdiagnoses could have been avoided by thorough electrophysiological examination using a standardized protocol.

[Quantitative study on cultivation of canine myoblasts]. / Quantitative Untersuchungen zur Kultivierung caniner Myoblasten.

Skeletal muscle cell culture is an important tool to discover the pathogenesis of rare canine neuromuscular diseases. The aim of the current study was to improve an existing clinical protocol to extract and cultivate canine myoblasts by using different enzymes for tissue digestion. The contamination of the mixed culture with fibrocytes should be minimized, a higher number of myoblasts with a shorter lag period should be gained and the influence of transport length on the myoblast numbers should be assessed. Twenty-one muscle biopsies (n = 21) from healthy dogs were taken, mechanically trimmed, enzymatically dissociated with either Protease or Trypsin and cultured under identical conditions for 168 hours. To distinguish and quantify myoblasts and fibrocytes an immunocytochemical staining of the muscle cell specific intermediate filament desmin was performed. To analyse the influence of a transport on the samples eight biopsies were cultured with either Trypsin or Protease at the Using Protease a significant higher production and a morphological better proliferation of myoblasts (P = 0.0102) was achieved. The average percentage of myoblasts was 78.96% using Protease and 54.68% using Trypsin. The duration of the transport (1-3 days) did not result in any significant changes in total myoblast cell counts (P = 0.798). This reveals the possibility to send muscle biopsies from distant clinics to a specialised laboratory. In conclusion, the use of Protease is an improvement for cultivating canine myoblasts and provides better conditions for further investigations elucidating pathogenesis of rare neuromuscular diseases.

Characterization and differentiation potential of rat ventral mesencephalic neuronal progenitor cells immortalized with SV40 large T antigen.

Neuronal progenitor cells (NPCs) possess high potential for use in regenerative medicine. To overcome their limited mitotic competence, various immortalization strategies have been applied that allow their prolonged maintenance and expansion in vitro. Such immortalized cells can be used for the design and discovery of new cell-based therapies for neurodegenerative diseases, such as Parkinson's disease. We immortalized rat ventral mesencephalic NPCs by using SV40 large T antigen (SV40Tag). All cell clones displayed a two- to three-fold higher proliferation rate compared with the primary cells. In order to induce dopaminergic differentiation of generated cell clones, both glial-derived neurotrophic factor and di-butyryl cyclic adenosine monophosphate were applied. Treated cells were then characterized regarding the expression of dopaminergic lineage markers, differentiation of various cell populations, calcium imaging in the presence of kainate, and immunohistochemistry after intrastriatal transplantation. Treated cells displayed morphological maturation, and calcium imaging revealed neuronal properties in the presence of kainate. These cells also expressed low mRNA levels of the dopamine transporter and tyrosine hydroxylase (TH), although no TH-immunopositive neurons were found. Intrastriatal transplantation into the neurotoxin-lesioned rats did not induce further differentiation. As an alternative approach, we silenced SV40Tag with short interfering RNA, but this was not sufficient to trigger differentiation into dopaminergic neurons. Nevertheless, neuronal and glial cells were detected as shown by beta-tubulin type III and glial fibrillary acidic protein staining, respectively. SV40Tag cells are suitable for carrying out controlled genetic modifications as shown by overexpression of enhanced green fluorescence protein after efficient non-viral transfection.

Synaptic currents and transmitter responses in human NT2 neurons differentiated in aggregate culture.

Postmitotic neurons were generated from the human NT2 teratocarcinoma cell line in a novel cell aggregate differentiation procedure. The NT2 model neurons express punctate immunoreactivity for synapsin and for cell markers related to GABAergic and glutamatergic neurotransmission. Using the outside-out patch-clamp configuration, we characterized the kinetics of currents elicited by a rapid application of the amino acid neurotransmitters. Moreover, we detected spontaneous postsynaptic currents in glia free cell cultures that may result from the firing activity of glutamatergic and GABAergic NT2 neurons. These cultured spontaneously active networks may be a useful tool to analyze factors that modulate the formation and efficacy of synapses between human neurons.

Reduced delayed rectifier K+ current, altered electrophysiology, and increased ventricular vulnerability in MLP-deficient mice.

BACKGROUND: Mice with a knockout (KO) of muscle LIM protein (MLP) exhibit many morphologic and clinical features of human cardiomyopathy. In humans, MLP-expression is downregulated both in ischemic and dilative cardiomyopathy. In this study, we investigated the effects of MLP on the electrophysiologic phenotype in vivo and on outward potassium currents. METHODS AND RESULTS: MLP-deficient (MLPKO) and wild-type (MLPWT) mice were subjected to long-term electrocardiogram (ECG) recording and in vivo electrophysiologic study. The whole-cell, patch-clamp technique was applied to measure voltage dependent outward K+ currents in isolated cardiomyocytes. Long-term ECG revealed a significant prolongation of RR mean (108 +/- 9 versus 99 +/- 5 ms), P (16 +/- 3 versus 14 +/- 1 ms), QRS (17 +/- 3 versus 13 +/- 1 ms), QT (68 +/- 8 versus 46 +/- 7 ms), QTc (66 +/- 6 versus 46 +/- 7 ms), JT (51 +/- 7 versus 34 +/- 7 ms), and JTc (49 +/- 5 versus 33 +/- 7 ms) in MLPKO versus MLPWT mice (P < .05). During EP study, QT (80 +/- 8 versus 58 +/- 7 ms), QTc (61 +/- 6 versus 45 +/- 5 ms), JT (62 +/- 9 versus 43 +/- 6 ms), and JTc (47 +/- 5 versus 34 +/- 5 ms) were also significantly prolonged in MLPKO mice (P < .05). Nonsustained VT was inducible in 9/16 MLPKO versus 2/15 MLPWT mice (P < .05). Analysis of outward K+ currents in revealed a significantly reduced density of the slowly inactivating outward K+ current IK, slow in MLPKO mice (11 +/- 5 pA/pF versus 18 +/- 7 pA/pF; P < .05). CONCLUSION: Mice with KO of MLP exhibit significant prolongation of atrial and ventricular conduction and an increased ventricular vulnerability. A reduction in repolarizing outward K+ currents may be responsible for these alterations.

Dopaminergic properties and function after grafting of attached neural precursor cultures.

Generation of dopaminergic (DA) neurons from multipotent embryonic progenitors represents a promising therapeutical strategy for Parkinson's disease (PD). Aim of the present study was the establishment of enhanced cell culture conditions, which optimize the use of midbrain progenitor cells in animal models of PD. In addition, the progenitor cells were characterized during expansion and differentiation according to morphological and electrophysiological criteria and compared to primary tissue. Here, we report that CNS precursors can be expanded in vitro up to 40-fold and afterwards be efficiently differentiated into DA neurons. After 4-5 days under differentiation conditions, more than 70% of the neurons were TH+, equivalent to 30% of the total cell population. Calcium imaging revealed the presence of calcium-permeable AMPA receptors in the differentiated precursors which are capable to contribute to many developmental processes. The overall survival rate, degree of reinnervation and the behavioral performance after transplantation of 4 days in-vitro-differentiated cells were similar to results after direct grafting of E14 ventral mesencephalic cells, whereas after shorter or longer differentiation periods, respectively, less effects were achieved. Compared to the amount of in-vitro-generated DA neurons, the survival rate was only 0.8%, indicating that these cells are very vulnerable. Our results suggest that expanded and differentiated DA precursors from attached cultures can survive microtransplantation and integrate within the striatum in terms of behavioral recovery. However, there is only a short time window during in vitro differentiation, in which enough cells are already differentiated towards a DA phenotype and simultaneously not too mature for implantation. However, additional factors and/or genetical manipulation of these expanded progenitors will be required to increase their in vivo survival in order to improve both the ethical and the technical outlook for the use of fetal tissue in clinical transplantation.

Congenital myasthenic syndrome due to a novel missense mutation in the gene encoding choline acetyltransferase.

Congenital myasthenic syndromes are caused by different genetic defects affecting proteins expressed at the neuromuscular junction. Recently, the first molecular genetic defect resulting in a presynaptic congenital myasthenic syndrome has been reported: Recessive loss-of-function mutations in CHAT, the gene encoding choline acetyltransferase, were described in five congenital myasthenic syndrome families. In this study, we investigated three patients from two independent Turkish kinships. Clinically, all patients presented with moderate myasthenic symptoms including ptosis and muscle weakness with increased fatigability. Multiple episodes of sudden apnea were reported for all patients. One child suffering from a second, unrelated disorder, i.e. hepatocellular carcinoma, showed a severe myasthenic phenotype, requiring permanent ventilation. Genetically, we identified a novel missense mutation (I336T) in the CHAT gene homozygously in all three patients. Haplotype analysis revealed that the mutant allele cosegregates with the clinical phenotype in both families (maximum combined two-point LOD-score of 2.46 for D10S1793). In summary, we confirm that CHAT mutations are responsible for a clinically distinct form of congenital myasthenic syndrome, characterized by episodic apnea. Infections and stress may lead to a life-threatening failure of neuromuscular transmission in congenital myasthenic syndrome with episodic apnea. The observation of the same mutation (I336T) in two independent Turkish kinships may suggest a common origin, i.e. founder.

Amyotrophic lateral sclerosis (ALS) and mirror movements in a patient with polymicrogyria.

We report on a case of polymicrogyria with benign childhood epilepsy and amyotrophic lateral sclerosis (ALS). While performing dexterity tasks with either hand, strong unsustained mirror movements of the unintended hand were observed. The patient was seen over a period of three years and, as often seen in ALS, there was a moderate progress of the motor neuron disease affecting the upper and lower motor neuron in an asymmetrical manner. In addition, more rapidly progressive bulbar symptoms could be observed by the clinical and neurophysiological examination. MRI revealed polymicrogyria of the right frontal lobe with irregular bumpy inner and outer surface and abnormally thick and smooth cortex, dysplastic insular cortex and asymmetrically widened Sylvial fissure. No signs of atrophy, especially of the motorcortex and corticospinal tract were observed. The corpus callosum was completely developed and of normal size. We hypothesize an enrolment of the dysplastic right frontal lobe pathophysiology of the observed mirror movements.

Block of recombinant nicotinic receptor channels by IgG from myasthenic patients.

In myasthenia gravis (MG), specific antibodies directed against nicotinic acetylcholine receptor (nAChR) channels are produced. Recently, a distinct blockade of native embryonic-type nAChR channels by purified IgG from MG patients has been demonstrated. In the present study, we investigated the interaction of myasthenic IgG with recombinant embryonic- or adult-type nAChR channels expressed on human embryonic kidney (HEK) 293 cells. For the experiments, the patch clamp technique was applied in combination with an ultra-fast application system for agonists. Repetitive 20-ms pulses of 1 mM acetylcholine (ACh) were applied with or without purified IgG added to the perfusion system. The purified IgG from MG patients blocked currents through both, embryonic- and adult-type nAChR channels to a similar extent. A block by myasthenic IgG of adult-type nAChR channels, which are present exclusively at the postsynaptic membrane of the neuromuscular synapse, was shown to occur. The reversible pharmacological blockade of adult-type nAChR channels by myasthenic IgG may be one factor responsible for rapid fluctuations of weakness or rapid recovery of muscle strength after plasmapheresis in MG.