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LIM domain-binding 3 (LDB3) is a member of the Enigma family of PDZ-LIM proteins. LDB3 has been reported as a striated muscle-specific Z-band alternatively spliced protein that plays an important role in mechanosensory actin cytoskeleton remodeling. This study shows that LDB3 is broadly expressed in the central and peripheral nervous system of human and mouse. LDB3 is predominantly expressed in the adult stages compared to early development and at a significantly higher level in the spinal cord than in the brain. As in skeletal muscle and heart, LDB3 is extensively alternatively spliced in the neurons. Three novel splice isoforms were identified suggesting splicing-dependent regulation of LDB3 expression in the nervous system. Expression of LDB3 in the motor cortex, cerebellum, spinal motor neuron, peripheral nerve, and neuromuscular junction in addition to skeletal muscle indicates important roles for this PDZ-LIM family protein in motor planning and execution. Moreover, expression in the hippocampal neurons suggests roles for LDB3 in learning and memory. LDB3 interactors filamin C and myotilin are also expressed in the spinal motor neuron, nerve, and neuromuscular junction, thereby providing the basis for neurogenic manifestations in myopathies associated with mutations in these so-called muscle proteins., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Z-disc-associated, alternatively spliced, PDZ motif-containing protein (ZASP) is a principal component of the sarcomere. The three prevalent isoforms of ZASP in skeletal muscle are generated by alternative splicing of exons 9 and 10. The long isoforms, either having (ZASP-L) or lacking exon 10 (ZASP-LΔex10), include an N-terminal PDZ domain, an actin-binding region (ABR) with a conserved motif (ZM), and three C-terminal LIM domains. The short isoform (ZASP-S) lacks the LIM domains. Mutations, A147T and A165V, within the ZM of ZASP-LΔex10 cause myofibrillar myopathy, but the mechanism is unknown. We have prepared these proteins, their ABR, and the respective mutant variants in recombinant form, characterized them biophysically, and analyzed their actin-binding properties by surface plasmon resonance and electron microscopy. All the proteins were physically homogeneous and monomeric and had circular dichroic spectra consistent with partially folded conformations. Comparison of the NMR HSQC spectra of ZASP-S and the PDZ domain showed that the ABR is unstructured. ZASP-S and its mutant variants and ZASP-LΔex10 all bound to immobilized G-actin with high affinity (K d ≈ 10 -8 to 10 -9 M). Constructs of the isolated actin-binding region missing exon 10 (ABRΔ10) bound with lower affinity (K d ≈ 10 -7 M), but those retaining exon 10 (ABR+10) did so only weakly (K d ≈ 10 -5 M). ZASP-S, and the ABRΔ10, also induced F-actin and array formation, even in conditions of low ionic strength and in the absence of KCl and Mg 2+ ions. Interestingly, the ZM mutations A147T and A165V did not affect any of the results described above.

A case of a cystic neurinoma of the trochlear nerve, originally interpreted as an intrinsic brainstem lesion, is presented. The history of the disease, its clinical picture and surgical treatment are described in detail.

The authors report a new case of ganglion cyst of the peroneal nerve. The rarity of this entity induced the authors to report this new case, emphasizing the value of MRI which constitutes a reliable non-invasive examination for the visualization of this lesion.

The purpose of our work was to measure the accuracy and reliability of MR-Angiography in the study and follow-up of intracranial arteriovenous malformations, and in particular to evaluate the results of endovascular treatment. Over an 18-month period 4 patients with such malformations were examined by MR-Angiography. There was an angioma of the corpus callosum, a left parieto-rolandic angioma, a posterior thalamic angioma and a cerebellar angioma. All examinations were performed with a Magneton-Impact 1 Tesla machine (Siemens, Erlangen, Germany), using a head coil, MR-Angiography with time-of-flight sequences and differential arterial and venous saturations. Each patient was examined by MR-Angiography first at the beginning of treatment, then when ambulatory after embolization. The morphological study applied to the afferent vessels, the nidus and the efferent veins. MR-Angiography proved to be very good in identifying the arteries feeding the malformation, and this made it easier to evaluate the reduction of their input after treatment, without having recourse to any arteriography. Beside, analysis of the nidus was facilitated by the judicious arrangement of arterial and venous saturations. In fact, the systematic use of MR-Angiography in the follow-up of intracranial arteriovenous malformations makes it possible to measure, with full reliability, the efficacy of the endovascular treatment under conditions of comfort unequalled in these out-patients, and selective angiography sequences need to be performed only during therapeutic phases.