Limb-girdle muscular dystrophy due to emerin gene mutations.

BACKGROUND: Emery-Dreifuss muscular dystrophy, caused by EMD gene mutations, is characterized by humeroperoneal muscular dystrophy, joint contractures, and conduction defects and is often associated with sudden cardiac death, even without prior cardiac symptoms. OBJECTIVE: To describe the clinical and molecular features of 2 patients with limb-girdle muscular dystrophy with mutations in EMD. DESIGN: Case reports. SETTING: Academic research. PATIENTS: Two male patients manifested proximal dominant muscle involvement, with minimal or no joint and cardiac involvement. MAIN OUTCOME MEASURES: Muscle biopsy and mutation analysis results. RESULTS: Immunohistochemistry revealed an absence of emerin staining in muscle biopsy specimens. Mutation analysis identified nonsense mutations in EMD. CONCLUSIONS: Mutations in EMD may indicate a limb-girdle muscular dystrophy phenotype. Identification of emerin deficiency among patients with limb-girdle muscular dystrophy is essential to prevent cardiac catastrophe.

Subclinical central pontine myelinolysis following liver transplantation.

Central pontine myelinolysis (CPM) is a demyelinating disorder of unknown origin that almost exclusively affects the central portion of the basis pontis, and is one of the fatal neurological complications after liver transplantation. We describe two children with CPM detected incidentally after liver transplantation. To our knowledge, this is the first report of CPM diagnosed antemortem in children who had undergone liver transplantation. In our patients, there were no clinical manifestations associated with CPM. We conclude that, including silent cases such as our patients, CPM may be more prevalent than previously appreciated following liver transplantation.

A case of hypertensive encephalopathy with extensive spinal lesions on MRI.

A 14-year-old female had repeated vomiting, headache, abdominal pain, visual field deficit and lethargy at the onset of hypertensive encephalopathy. Cerebrospinal fluid (CSF) test revealed a high level of IgG and protein. MRI demonstrated no supratentorial cerebral lesions but hyperintense lesions were observed from the lower pons to the Th8 level of spinal cord and cerebellar cortex on T2 weighted and FLAIR images without contrast enhancement. The two antihypertensive drugs stabilized to control her blood pressure and improved her clinical symptoms. Reexamination of MRI and cerebrospinal fluid test also revealed clear improvement of the above abnormalities. The abnormal findings on abdominal CT and renography led us to suspect renal infarction. Abdominal angiography demonstrated multifocal stenoses of renal interlobar arteries, which were supposed to supply the renal infarcted regions. These suggested that the renal infarctions due to fibromuscular dysplasia caused systemic hypertension. There have been only two reports that demonstrated spinal cord lesions in reversible posterior leukoencephalopathy syndrome (RPLES). We report extensive spinal lesions on MRI and a high level of IgG in CSF at the subacute phase in a young female with RPLES associated with hypertensive (brainstem) encephalopathy.

Loss of Borealin/DasraB leads to defective cell proliferation, p53 accumulation and early embryonic lethality.

Borealin/DasraB is a member of the chromosomal passenger protein complex (CPC) required for proper segregation of chromosomes during mitosis. In Drosophila melanogaster, inactivation of Borealin/DasraB results in polyploidy, delayed mitosis and abnormal tissue development, indicating its critical role for cell proliferation. However, the in vivo role of mammalian Borealin/DasraB remains unclear. Here, we analyzed the expression of Borealin/DasraB and found that borealin is widely expressed in embryonic tissues and later restricted to adult tissues which relies on rapid cell proliferation. To determine the role of borealin during mouse development, we generated borealin-null mice through targeted disruption. While heterozygous mice developed normally, disruption of both borealin alleles resulted in early embryonic lethality by 5.5 dpc (days postcoitus) due to mitotic defects and apoptosis in blastocyst cells that showed microtubule disorganization and no CPC enrichment. At 5.5 dpc, borealin-null embryos exhibited excessive apoptosis and elevated expression of p53. However, loss of p53 did not abrogate or delay embryonic lethality, revealing that Borealin/DasraB inactivation triggered impaired mitosis and apoptosis though p53-independent mechanisms. Our data show that Borealin/DasraB is essential for cell proliferation during early embryonic development, and its early embryonic lethality cannot be rescued by the loss of p53.

A neurosphere-derived factor, cystatin C, supports differentiation of ES cells into neural stem cells.

Although embryonic stem (ES) cells are capable of unlimited proliferation and pluripotent differentiation, effective preparation of neural stem cells from ES cells are not achieved. Here, we have directly generated under the coculture with dissociated primary neurosphere cells in serum-free medium and the same effect was observed when ES cells were cultured with conditioned medium of primary neurosphere culture (CMPNC). ES-neural stem cells (NSCs) could proliferate for more than seven times and differentiate into neurons, astrocytes, and oligodendrocytes in vitro and in vivo. The responsible molecule in CMPNC was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, which turned out to be cystatin C. Purified cystatin C in place of the CMPNC could generate ES-NSCs efficiently with self-renewal and multidifferentiation potentials. These results reveal the validity of cystatin C for generating NSCs from ES cells.

Prospective characterization of neural stem cells by flow cytometry analysis using a combination of surface markers.

Neural stem cells (NSCs) with self-renewal and multilineage differentiation properties can potentially repair degenerating or damaged neural tissue. Here, we have enriched NSCs from neurospheres, which make up a heterogeneous population, by fluorescence-activated cell sorting (FACS) with antibodies against syndecan-1, Notch-1, and integrin-beta1, which were chosen as candidates for hematopoietic cell-or somatic stem cell-markers. Antigen-positive cells readily initiated neurosphere formation, but cells lacking these markers did so less readily. Doubly positive cells expressing both syndecan-1 and Notch-1 underwent neurosphere formation more efficiently than did singly positive cells. The progeny of sorted cells could differentiate into neurons and glial cells both in vitro and in vivo. These antibodies were also useful for isolating cells from the murine embryonic day 14.5 brain that efficiently formed neurospheres. In contrast, there was no distinct difference in neurosphere formation efficiency between Hoechst 33342-stained side population cells and main population cells, although the former are known to have a stem cell phenotype in various tissues. These results indicate the usefulness of syndecan-1, Notch-1, and integrin-beta1 as NSC markers.