Biomedical subjects
Publications and source records attributed to H Taira.
We report on a rare, calcified, plasma cell tumor of the spine causing progressive myelopathy. Other unusual features were the lack of an osseous lesion at the site of the mass, considerable calcified amyloid within the mass but no identifiable amyloid elsewhere, and normal serum immunoelectrophoresis.
Sendai virus envelope glycoproteins, F and HN, mature during their transport through the endoplasmic reticulum (ER) and Golgi complex. To better understand their maturation processes in the ER, we investigated the time course of their interactions with three ER- resident molecular chaperones, BiP, calnexin (CNX), and calreticulin (CRT), in Sendai virus-infected HeLa cells. Pulse-chase and immunoprecipitation analyses using antibodies against each virus glycoprotein or ER chaperone revealed that F precursor interacted with CNX transiently (t(1/2)=8 min), while HN protein displayed longer and sequential interactions with BiP (t(1/2)=8 min), CNX (t(1/2)=15 min), and CRT (t(1/2)=20 min). HN interacted with the three ER chaperones not only as a monomer but also as a tetramer for several hours, suggesting mechanism(s) to undergo chaperone-mediated quality control of an assembled HN oligomer in the ER. The kinetics of dissociation of the HN-chaperone complexes exhibited a marked delay in the presence of proteasome inhibitors, suggesting that a part of HN associated with BiP, CNX, and CRT is destined to be degraded in the proteasome-dependent pathway. Further, the associations between virus glycoproteins and CNX or CRT were impaired by castanospermine, an inhibitor of ER glucosidase I and II, confirming that these interactions require monoglucosylated oligosaccharide on F(0) and HN peptides. These findings together suggest that newly synthesized F protein undergoes rapid maturation in the ER through a transient interaction with CNX, whereas HN protein requires more complex processes involving prolonged association with BiP, CNX, and CRT for its quality control in the ER.
A case of reconstruction of the upper lip with a bipedicled submental flap is described. Although the mobility of the flap was restricted, the arterial blood supply was abundant by altering the single-pedicled flap into a bipedicled flap. This flap is a good color and texture match to the face, and surpasses other flaps in reconstruction of the mustache or beard in male patients.
We have developed a method for the immunoaffinity purification of calnexin, an endoplasmic reticulum molecular chaperone, and analyzed the molecular weight of purified calnexin using matrix-assisted laser adsorption ionization time of flight mass spectrometry (MALDI TOF-MS). Calnexin was thereby found to have a molecular weight of 66.1 x 10(3), which is nearly identical to the molecular weight estimated from the protein sequence.
Silk gland elongation factor 1 (EF-1) consists of four subunits: alpha, beta, beta', and gamma. EF-1 beta beta' gamma catalyzes the exchange of GDP for GTP on EF-1 alpha and stimulates the binding of EF-1 alpha-dependent aminoacyl-tRNA to ribosomes. The carboxy-terminal regions of the EF-1 beta subunits from various species are highly conserved. We examined the region of EF-1 beta' that binds to EF-1 alpha by in vitro binding assays, and examined the GDP/GTP exchange activity using deletion mutants of a GST-EF1 beta' fusion protein. We thereby suggested a pivotal amino acid region, residues 189-222, of EF-1 beta' for binding to EF-1 alpha.
Swine hemagglutinating encephalomyelitis virus (HEV) strain 67N was inoculated into the sciatic nerve or the right leg crural muscle of rats. In both cases, the virus was isolated first from the caudal half of the spinal cord on day 2 after inoculation, and from the rostral half of the spinal cord and the brain on day 3. The virus titers in the brain reached a maximum when the infected rats developed CNS symptoms on day 5. Using confocal laser scanning microscope, fluorescent positive cells were first found in the lumbar dorsal root ganglion (DRG) and spinal cord ipsilateral of the inoculated leg on day 3. Antigen positive neurons were found bilaterally in the lumbar DRG and spinal cord on day 4. On day 5 specific fluorescence was observed in the neurons of the cerebral cortex, hippocampus, brainstem and Purkinje cells in the cerebellum.
The role of intramolecular disulfide bonds in the fusion (F) protein of Sendai virus was studied. The 10 cysteine residues were changed to serine residues using site-directed mutagenesis. None of the cysteine mutant F proteins reacted with a monoclonal antibody specific for the mature conformation of the F protein, but eight of ten mutants reacted with an immature conformation-specific monoclonal antibody. The transport of these mutant proteins to the cell surface was drastically reduced. All of the cysteine mutant F proteins remained sensitive to endoglycosidase H (endo H) for 3 h after their synthesis. Moreover, cell surface transport of the hemagglutinin-neuraminidase (HN) protein co-expressed with each of these cysteine mutant F proteins was also reduced. These results suggest that all cysteine residues participate in the formation of intramolecular disulfide bonds, that co-translational disulfide bond formation is crucial to the correct folding and intracellular transport of the F protein, and that interaction of the F and HN proteins takes place intracellulary.
The previous years mean temperature of July, total solar radiation of July and August and the male flowering index were used to predict atmospheric pollen counts. We examined the adaptability of these predictions and we get following results: 1. Following good harvest years of male flower, atmospheric pollen counts predicted by previous year's mean temperature of July and the total solar radiation of July and August are higher than the actual atmospheric pollen count. 2. Prediction of atmospheric pollen counts by factors within the previous five years are more exact because matured Cryptomeria forests are increasing yearly. 3. There are few errors in prediction by the flowering index because the flower index reflects the actual harvest of male flower.
We report a case of a 39-year-old man with a severely deformed hand resulting from an injury sustained in a traffic accident at 2 years of age. A Marjolin ulcer appeared on the cicatricial area 3 years ago. After radical surgery for squamous cell carcinoma, we planned to realign the axis of the ulnarly flexed hand. Prior to surgery, we produced a solid model of the bony framework using laser lithography based on 3-D CT digital image data. The solid model furnished us and the patient with precise information on the deformity and allowed us to perform preoperative simulation surgery. By a two-stage wedge-shaped ostectomy at the end of the radius, the ulnarly deviated axis of the hand was realigned from 100 to 30 degrees (approximate) in clinical measurement and the patient was quite satisfied with the resulting function and appearance. However, there are some disadvantages of the laser lithography solid model: the cost is high, the resin material is very hard and difficult to operate on, and the model does not include soft-tissue structures. The development of a model in the future that includes vessels, nerves, and tendons will enable surgeons to transfer more precisely the results of the simulation surgery to the patient in the operating room.
Polyamine-brushed substrata for cell culture were designed by solvent casting of polystyrene-graft-polyamine copolymer (SA) on hydrophobically modified glass surface, and adhesion, spreading, and proliferation of bovine aortic endothelial cells (BAEC) on these substrata were evaluated. Adhesion and spreading of BAEC increased with increasing polyamine content in the copolymer. Close correlation was found between cellular spreading and subsequent cell growth; the surface inducing better spreading of adhered cells showed higher endothelial cell growth. Adhesion and spreading of BAEC were significantly influenced by fetal calf serum (FCS)-pretreatment of the SA copolymer surfaces, being increased with increasing polyamine content, whereas on bovine serum albumin (BSA)-preabsorbed surfaces, BAEC adhesion was considerably prevented and eventually no cell spreading was observed. Then, adsorption of cell-adhesion proteins, fibronectin (FN), and vitronectin (VN), out of FCS onto SA copolymer surfaces were evaluated using enzyme immunoassay. Both FN and VN adsorption on SA copolymer surfaces were increased with increasing polyamine content in the copolymer, suggesting a crucial role of these cell-adhesion proteins in BAEC adhesion and subsequent growth behavior on SA copolymer surfaces.
In contrast to the wild type Sendai virus fusion protein (F), a mutated F to possess a cleavage site similar to that of virulent Newcastle disease virus F, could be cleaved by proteases present in COS cells. When mutated F and hemagglutinin-neuraminidase (HN) were coexpressed at the cell surface, syncytium formation was observed.
We identified GABAA receptor subunits in rat retina using PCR. The high degree of conservation among previously described members of ligand-gated anion channels in transmembrane domains was used to design degenerate sense and antisense oligonucleotides. These oligonucleotides were used as primers for PCR, which was applied to the rat retina cDNA. Analysis of clones derived from the PCR amplification identified the GABAA alpha 1, beta 1, beta 3, and gamma 2 subunits and the glycine alpha 1 subunit. In addition, two clones closely related to the human GABAA rho-subunit class were obtained. Molecular cloning revealed one of them as the rat counterpart of the human rho 2 subunit. Northern blot analysis demonstrated the expression of mRNAs for rho subunits in retina. These results further support the hypothesis that bicuculline-insensitive GABA channels in rat retina are comprised of rho subunits.
A putative movement protein of molecular mass 50 kDa encoded by the ORF2 of the apple chlorotic leaf spot virus (ACLSV) genome was expressed in Escherichia coli using an expression vector and was then used to produce an antiserum. Immunoblot analysis using an antiserum raised against this protein showed that the ORF2 protein of ACLSV was detected in both cell wall and cell membrane fractions prepared from infected Chenopodium quinoa tissues. The ORF2 protein from infected tissues had a molecular mass of 52 kDa, larger than that of the full-length ORF2 protein (50 kDa protein) expressed in E. coli. Incubation of the 52 kDa protein with alkaline phosphatase resulted in a decrease in its apparent molecular mass from 52 kDa to 50 kDa, strongly suggesting that the ORF2 protein of ACLSV is phosphorylated in infected plant tissues.
Generally, airborne scattering of sugi (Cryptomeria japonica D. Don) pollen begins to be observed coincidentally with the flowering of the male sugi flowers between February and April. However the male sugi flowers disperse a certain amount of pollen in early January, only small levels of which can be detected with a Durham's sampler. In some Japanese cedar pollinosis patients, allergic symptoms have been reported to occur in early January. Among 1,366 Japanese cedar pollinosis patients studied, 265 have experienced allergic symptoms before the first day of pollen scattering as determined with a Durham's sampler. Accordingly, it is suggested that substantial amounts of sugi pollen are scattered from early January, and that clinical symptoms can be induced in highly sensitive Japanese cedar pollinosis patients from early January, even before the flowering of sugi.
Atmospheric pollen surveys have been conducted using Durham's standard sampler for 12 years in Toyama Prefecture. The relationships between Sugi (Japanese cedar, Cryptomeria japonica D. Don) pollen and some indices of climatic conditions were analyzed. The results were as follows: 1. Total pollen counts showed a tendency to increase for 12 years, although the variation of the count was relatively large. 2. Significant correlations were found between pollen counts and some indices of the climatic conditions in July of the previous year, such as duration of sunshine, mean daily temperature and daily maximum, as well as minimum temperature. 3. Significant correlation was found between pollen count and duration of sunshine in January and March, and the amount of snowfall in March of the observed year using multiple regression analysis. Pollen counts were shown to be relatively high in years with short sunshine in January and long sunshine and heavy snow in March.
We have cloned and sequenced a cDNA coding for rice elongation factor 1 beta (EF-1 beta). The clone was 1420 bp long and contained an open reading frame coding for 229 amino acids. The overall identity between rice EF-1 beta and rice EF-1 beta' [Matsumoto, S., Oizumi, N., Taira, H. and Ejiri, S. (1992) FEBS Lett. 311, 46-48] is 60% at the amino acid sequence level; a higher percent identical residues (81%) were especially observed in the C-terminal region. Rice EF-1 beta has no conserved phosphorylation site for casein kinase II and no leucine zipper motif, although these motifs are well conserved in EF-1 delta (= beta in plants) subunits of animal EF-1.
Direct interactions of Friend spleen focus-forming virus glycoprotein gp55 with either erythropoietin receptor (EpoR) or interleukin (IL)2 receptor beta chain (IL2R) (but not with IL3 receptor) have been reported to induce factor-independent prolonged proliferation of erythroid or lymphoid cells. In order to clarify the molecular mechanism by which EpoR-gp55 complex transmits an aberrant growth signal in the absence of erythropoietin, various chimeric receptors constituted with IL2R, EpoR or IL3 receptor were constructed. It was found that coexpression of gp55 and the chimeric receptors containing the cytoplasmic domains of EpoR and the extracellular domains of IL3 (or IL2) receptor in IL3-dependent Ba/F3 cells results in factor-independent growth. Since gp55 in cell membrane has only a two amino acid tail in the cytoplasmic domains and thus cannot interact with EpoR in cytoplasm, our data suggest that gp55 does not bind EpoR directly but interacts with EpoR through third membrane component(s).
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