Identification of neural genes using Xenopus DNA microarrays.

To isolate novel genes regulating neural induction, we used a DNA microarray approach. As neural induction is thought to occur by means of the inhibition of bone morphogenetic protein (BMP) signaling, BMP signaling was inhibited in ectodermal cells by overexpression of a dominant-negative receptor. RNAs were isolated from control animal cap explants and from dominant-negative BMP receptor expressing animal caps and subjected to a microarray experiment using newly generated high-density Xenopus DNA microarray chips representing over 17,000 unigenes. We have identified 77 genes that are induced in animal caps after inhibition of BMP signaling, and all of these genes were subjected to whole-mount in situ hybridization analysis. Thirty-two genes showed specific expression in neural tissues. Of the 32, 14 genes have never been linked to neural induction. Two genes that are highly induced by BMP inhibition are inhibitors of Wnt signaling, suggesting that a key step in neural induction is to produce Wnt antagonists to promote anterior neural plate development. Our current analysis also proves that a microarray approach is useful in identifying novel candidate factors involved in neural induction and patterning.     

Gene-deletion and carrier detections,and prenatal diagnosis of Duchenne muscular dystrophy by analysis of the dystrophin gene amplified by polymerase chain reaction

Polymerase chain reaction (PCR)-based diagnosis was carried out in 62 patients (57 probands) with Duchenne or Becker muscular dystrophy (DMD or BMD) and 226 members in 57 families. The PCR studies were also performed for carrier detection in 57 mothers and 58 sisters, and prenatal diagnosis of 4 fetuses at risk of DMD. The PCR with 7 sets of primers, which amplify 7 different exon-sequences of the dystrophin gene, detected gene deletion of at least one exon in 49% of the probands. The PCR with the other 4 primer sets, which amplify 3 intragenic loci, and subsequent endonuclease digestion detected in 84% of the mothers a heterozygous pattern in at least one such locus/segment. Using the same primer sets, carrier detection was successful in 5 sisters of familial DMD cases, while recombination between the ERT87 and the 3 end intragenic loci was observed in 11% of family members studied. Prenatal diagnosis was made in all the 4 fetuses; two males were affected, one male fetus non-affected, and the remaining one female fetus a carrier. Thus, the PCR study and the primers used in the present study are useful and convincing for rapid diagnosis of DMD and/or BMD.     

A promiscuous T cell hybridoma restricted to various I-A molecules

In a previous study, we identified T cell receptor and major histocompatibility complex (MHC) contact sites on the pigeon cytochrome c p43-58 peptide. Positions 46 and 54 of p43-58 were shown to be the MHC-binding sites. Specific amino acids were identified on the MHC-binding sites which bound to the relevant I-A molecule. In the present study, using NOD (I-A^g7) mice, we established a T cell hybridoma, NOE33-1-2, specific for a p43-58 analog 46R50E54A with arginine (R) and alanine (A) at positions 46 and 54, respectively. Interestingly, NOE 33-1-2 recognized 46R50E54A in the presence of not only I-A^g7, but also I-A^{d, s, u and v}. In contrast to previous reports that promiscuous T cells were able to recognize peptide antigens with various HLA-DR or I-E molecules consist of monomorphic α and polymorphic β chains, the promiscuous T cell clone NOE33-1-2 recognized peptides with various I-A molecules lacking the monomorphic chain.     

Complete Nucleotide Sequence and Phylogenetic Analyses of Hepatitis B Virus Isolated from Two Pileated Gibbons

Virus-like particles (VLPs, named HmTV1-17), about 40nm in diameter were found in the violet root rot fungus Helicobasidium mompa Tanaka strain No. 17, which had been isolated from an apple tree. Purified preparations of HmTV1-17 contained two species of double-stranded RNA (dsRNA), designated 17L and 17S. cDNAs were constructed from HmTV1-17 genomic dsRNAs purified using CF-11 cellulose column chromatography. The sequences of 17L and 17S cDNA comprised 5207 and 2096bp, respectively. Although 17S has no large open reading flame (ORF) on either strand, 17L has two large overlapping ORFs. The 5 located ORF1 encodes the coat protein (CP, 788 amino acids), whereas the gene product of ORF2, which is in the –1 frame relative to ORF1, shows the typical features of a RNA dependent RNA polymerase (RDRP, 845 amino acids). Phylogenetic analysis based on RDRP showed that HmTV1-17 is closely related to Sphaeropsis sapinea SsRV1, a member of the genus Totivirus from filamentous fungus S. sapinea.     

A novel Fc receptor for IgA and IgM is expressed on both hematopoietic and non-hematopoietic tissues

By contrast to well-defined Fc gamma and Fc epsilon receptors, the structural and functional characteristics of Fc mu receptor are unclear. We have recently described a novel mouse Fc receptor, designated Fc alpha/mu receptor, and its human homologue, which bind both IgM and IgA. Here we show that the Fc alpha/mu receptor is expressed on mature, but not immature, B lymphocytes and acquires the ability to bind IgM and IgA antibodies after stimulation of B lymphocytes. Moreover, stimulation with phorbol 12-myristate 13-acetate increased endocytosis of IgM-coated microparticles mediated by the Fc alpha/mu receptor expressed on pro-B cell line Ba/F3 cells. We also show that the Fc alpha/mu receptor is expressed in secondary lymphoid organs, such as lymph node and appendix, kidney and intestine, suggesting an important role of the receptor for immunity in these organs.     

MULTIPLE PRIMARY MALIGNANT FIBROUS HISTIOCYTOMA OF THE STOMACH AND SMALL INTESTINE

A case of multicentric malignant fibrous histiocytoma of the stomach and small intestine is reported. The patient was a 60-year-old man who had total gastrectomy under an impression of a gastric carcinoma. The resected stomach revealed a large polypoid mass in the antral portion at the greater curvature. Three months later, he developed ileus and an 80 cm segment of the jejunum was removed. It contained two polypoid masses identical to that seen in the stomach. The tumors showed, in addition to the characteristic light microscopic appearances, strong positivity for alpha-1-antitrypsin by an immunoperoxidase technique, indicating the diagnosis of malignant fibrous histiocytoma (MFH). Electron microscopic findings were also consistent with MFH. We believe that this is the first well-documented case of MFH arising from the stomach and small intestine, to the best of our knowledge.     

Determination of the depth of 50% of maximum ionization, I50, for electron beams by the divided difference method

A new characterization of depth-ionization parameters for electron beams is empirically deduced from our data analysis based on the divided difference method (the DD method), which employs the numerical differential of an ionization curve. The important feature of the present method is that it does not necessarily require normalized percent depth-ionization (NPDI) data. The depth of 50% of maximum ionization, I50, which is an important parameter for electron beam dosimetry, can be deduced from the analysis of an unnormalized (or partial) depth-ionization (UDI) curve obtained over a short interval of depth. The values of I50 determined by the DD method are in agreement to within 0.1 mm for energies of 4, 6, and 9 MeV, compared with the ones determined by the TG-51 protocol method (or the conventional method), and the difference was 0.9 mm for 12 and 15 MeV. The dose at the reference depth, dref, calculated from I50 by the DD method, is found to be in agreement with TG-51 to within 0.1%. The field size dependence of the DD method using UDI data was studied for three field sizes: 6 x 6, 10 x 10, and 20 x 20 cm2. For all energies, the discrepancies of I50 as determined by both methods were 0.9 mm on average for the 6 x 6 cm2 fields and 0.6 mm for the other two field sizes. This dependence was remarkable for 6 x 6 cm2 fields for 12 and 15 MeV, and the discrepancies shown by the DD method were 1.2 mm for 12 MeV and 1.8 mm for 15 MeV, respectively. Since the reference field size in clinical dosimetry is usually 10 x 10 cm2, this dependence will not affect clinical dosimetry. The DD method could be an alternative option for checking beam quality in dose calibration.