BackgroundThe histological hallmark of multiple system atrophy (MSA) is the presence of filamentous aggregations of phosphorylated α-synuclein in oligodendrocytes, referred to as glial cytoplasmic inclusions (GCIs). Although GCIs can occur widely in the central nervous system, accumulation of phosphorylated α-synuclein in Schwann cells has not been reported in MSA. We immunohistochemically examined the cranial and spinal nerves, peripheral ganglia and visceral autonomic nervous system of patients with MSA (n = 14) and control subjects (n = 20).ResultsIn MSA, accumulation of phosphorylated α-synuclein was found in the cytoplasm of Schwann cells. These Schwann cell cytoplasmic inclusions (SCCIs) were also immunopositive for ubiquitin and p62. SCCIs were found in 12 of 14 patients with MSA (85.7 %). They were most frequent in the anterior nerve of the sacral cord and, to a lesser extent, in the cranial nerves (oculomotor, glossopharyngeal-vagus and hypoglossal nerves), and spinal and sympathetic ganglia. SCCIs were rarely found in the visceral organs. Immunoelectron microscopy demonstrated that the SCCIs consisted of abnormal filaments, 15–20 nm in diameter. No such inclusions were found in controls.ConclusionThe present findings indicate that Schwann cells are also involved in the disease process of MSA.

Background: Over 90% of Ewing's sarcoma/primitive neuroectodermal tumour (ES/PNET) cases have the t(11;22) chromosomal rearrangement, which is also found in other small round cell tumours, including desmoplastic small round cell tumour (DSRCT) and clear cell sarcoma (CCS). Although this rearrangement can be analysed by fluorescence in situ hybridisation (FISH) using routinely formalin fixed, paraffin wax embedded (FFPE) tissues when fresh or frozen tissues are not available, a sensitive and convenient detection method is needed for routine clinical diagnosis. Aims: To investigate the usefulness of newly developed probes for detecting EWS rearrangement resulting from chromosomal translocations using FISH and FFPE tissue in the clinical diagnosis of ES/PNET, DSRCT, and CCS. Methods: Sixteen ES/PNETs, six DSRCTs, and six CCSs were studied. Three poorly differentiated synovial sarcomas, three alveolar rhabdomyosarcomas, and three neuroblastomas served as negative controls. Interphase FISH analysis was performed on FFPE tissue sections with a commercially available EWSR1 (22q12) dual colour, breakapart rearrangement probe. Results: One fused signal and one split signal of orange and green, demonstrating rearrangement of the EWS gene, was detected in 14 of 16 ES/PNETs, all six DRSCTs, and five of six CCSs, but not in the negative controls. Conclusions: Interphase FISH using this newly developed probe is sensitive and specific for detecting the EWS gene on FFPE tissues and is of value in the routine clinical diagnosis of ES/PNET, DSRCT, and CCS.

The histological hallmark of multiple system atrophy (MSA) is accumulation of phosphorylated α-synuclein in oligodendrocytes. However, it is uncertain whether phosphorylated α-synuclein accumulates in astrocytes of MSA patients. We immunohistochemically examined the frontal and temporal lobes, basal ganglia, cerebellum, brainstem and spinal cord of patients with MSA (n = 15) and Lewy body disease (n = 20), and also in control subjects (n = 20). Accumulation of abnormally phosphorylated and aggregated α-synuclein was found in subpial and periventricular astrocytes in six of the 15 patients with MSA (40%). The structures were confined to the subpial surface of the ventro-lateral part of the spinal cord and brainstem, as well as the subependymal region of the lateral ventricles. They were not visualized by Gallyas-Braak staining, and were immunonegative for ubiquitin and p62. Immunoelectron microscopy revealed that the phosphorylated α-synuclein-immunoreactive structures in astrocytes were non-fibrillar and associated with granular and vesicular structures. The extent of phosphorylated α-synuclein-immunoreactive astrocytes was correlated with disease duration. No such structures were found in Lewy body disease or controls. Accumulation of phosphorylated α-synuclein can occur in subpial and periventricular astrocytes in patients with MSA, especially in those with a long disease duration.

Both nuclear factor erythroid 2 45 kDa subunit (p45) and BTB and CNC homolog 1 (Bach) transcription factors can form dimers with one of the small Maf proteins, and these heterodimers bind to the musculoaponeu-rotic fibrosarcoma oncogene (Maf) recognition element (MARE). MARE is known to act as a critical cis-regulatory element of ery-throid and megakaryocytic genes. Although detailed analyses of p45-null mutant mice and small maf compound mutant mice revealed that these factors are both critical for platelet production, the functional contributions of Bach1 and the relationship or redundancy between Bach1 and p45 in megakaryocytes remain to be clarified. To address these issues, we generated trans-genic lines of mice bearing human BACH1 cDNA under the control of the GATA-1 locus hematopoietic regulatory domain. The trans-genic mouse lines showed significant throm-bocytopenia associated with impaired matu-ration of the megakaryocytes, and they developed myelofibrosis. The megakaryo-cytes in the transgenic mice exhibited reduced proplatelet formation, and the modal ploidy class of megakaryocytes was 2N, indicating the impairment of endomitosis. Transcription of the p45 target genes was down-regulated and we indeed found that BACH1 binds to the thromboxane synthase gene, one of the target genes for p45 in megakaryocytes. These findings thus provide evidence that BACH1 acts as a tran-scriptional repressor in the regulation of MARE-dependent genes in megakaryocytes. (Blood. 2005;105:3100-3108)

Apoptosis and its dysregulation have been implicated in dysplastic and ineffective hematopoiesis and the neoplastic transformation of bone marrow in myelodysplastic syndrome (MDS). To explore the role of apoptosis in hematological disorders, we examined the frequency of apoptotic cells by the in situ end labeling method in bone marrow specimens from 37 patients with MDS [refractory anemia (RA) 10 cases, RA with excess of blasts (RAEB) 27 cases including 12 cases with leukemic transformation], 12 patients with MDS-derived acute myelogenous leukemia (AML) and 13 patients with de novo AML. In addition, we investigated the relationship of apoptosis to the immunohistochemical expression of bcl-2 and p53 in these cases, and the association of apoptosis, bcl-2, and p53 with the leukemic evolution of MDS by examining sequential bone marrow samples of the same patient from the time of initial diagnosis to the time of overt leukemia. The percentage frequency of apoptotic cells was significantly greater in MDS (RA: 9.46 ± 2.99%, m ± SD; RAEB: 5.60 ± 3.09) as compared with those in MDS-derived AML (0.62 ± 0.37), de novo AML (0.28 ± 0.11) and controls (1.00 ± 0.59). On the other hand, the cases of RAEB with leukemic transformation exhibited a lower frequency of apoptotic cells and a higher frequency of bcl-2- and p53-positive cells than those without transformation. When the RAEB cases transformed to AML, the frequency of apoptotic cells was significantly reduced (2.96 ± 1.54 → 0.62 ± 0.37), while the frequencies of bcl-2-positive cells and p53-positive cells were greater (10.88 ± 3.66 → 30.54 ± 7.14, and 20.21 ± 6.21 → 32.34 ± 14.71, respectively). In contrast to MDS-derived AML, over a half of de novo AML cases showed few p53-positive cells. These findings corroborate the earlier notion that apoptosis may play a substantial role in dysplastic and ineffective hematopoiesis in MDS. It is also suggested that the suppression of apoptosis associated with enhanced bcl-2 expression and p53 accumulation increases the probability of developing leukemia in MDS, and that oncogenetic development might be different between MDS-derived AML and de novo AML.