Search PubMed⌕ Search

Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 163 records · Page 9Linked to original sources
PubMed2000

[Intrapericardiac instillation of epirubicin for carcinomatous cardiac tamponade from breast cancer].

Three cases of carcinomatous cardiac tamponade from breast cancer are presented. All patients have had another recurrence and history of treatment. Though the prognoses were considered to be unfavorable, pericardiac drainage and the instillation of epirubicin were effective. Side effects of fever and dyspnea were experienced temporarily by two patients with no serious events. Following the systemic chemotherapy, two patients needed no supplemental drainage. All patients had a sufficient quality of life for about 1 year or longer. We found that positive therapy can be significant for such patients with advanced disease.

Aged↗
PubMed2000

The multigenic family of monogalactosyl diacylglycerol synthases.

Because the synthesis of monogalactosyldiacylglycerol (MGDG) is unique to plants, identified as an important marker of the plastid envelope, involved in a key step of plastid biogenesis and is the most abundant lipid on earth, MGDG synthase activity was extensively analysed at the biochemical and physiological levels. In the present paper, we present our current knowledge on the MGDG synthase's function, structure and topology in envelope membranes, and discuss possible roles in plant cell glycerolipid metabolism. The recent discovery of a multigenic family of MGDG synthases raised the possibility that multiple isoenzymes might carry out MGDG synthesis in various tissues and developmental stages.

Amino Acid Sequence↗
PubMed2000

Transcriptional regulation by light and phytohormones of the MGD gene in cucumber.

Monogalactosyldiacylglycerol (MGDG) synthase catalyses formation of MGDG, a major structural lipid of chloroplasts. We have already cloned a cDNA for the synthase from a cucumber cDNA library and shown that expression of this gene is regulated by light and a phytohormone, cytokinin. In the present study, we report the molecular basis for transcriptional regulation by light and cytokinin in detail. First, in terms of the enzyme activity, gradual increases in activity mediated by light and cytokinin treatments were observed. At the same time, however, the changes in the mRNA level showed different profiles, with a transient peak during the early stages of light and cytokinin treatment. The interval between the peak level of mRNA and enzyme activation implies the existence of a post-transcriptional regulatory system. In addition, a genomic clone of MGDG synthase isolated from a cucumber genome library was used for a motif search in databases, and this revealed that putative cis-acting elements for light and phytohormones exist in the 5'-upstream region of the MGD cucumber gene. Detailed analysis of this region for light- and cytokinin-responsive activity was performed using a -90 truncated 35 S minimal promoter/luciferase (LUC) reporter gene. It resulted in high levels of LUC expression in etiolated cucumber cotyledons in response to illumination and cytokinin treatment. These results indicate that this 5'-upstream region is involved in light- and cytokinin-enhanced MGD gene expression, and that light- and cytokinin-responsive enhancements of the MGDG synthase activity are regulated, at least in part, at the level of transcription.

Adenine↗
PubMed2000

Genome-wide expression-monitoring of jasmonate-responsive genes of Arabidopsis using cDNA arrays.

Jasmonates are generally considered to mediate signalling, such as defence responses, flowering and senescence. However, factors involved in the jasmonate signal-transduction pathway remain unclear. To clarify the functions and signalling mechanisms of jasmonates on a genome-wide level, we adopted a cDNA macroarray technique. We prepared nylon filters of a cDNA macroarray on which 2880 independent expressed sequence tag clones of Arabidopsis were blotted, and hybridized (33)P-labelled single-strand DNAs synthesized from mRNAs of methyl jasmonate (MeJA)-treated and untreated Arabidopsis plants to the nylon filters. By analysing the data from the cDNA macroarray, we identified many function-known and unknown genes as MeJA-responsive genes, and confirmed that the profiles of the expression showed good agreement with Northern-blot analysis. These results demonstrate the efficiency of the cDNA macroarray for systematically analysing jasmonate-responsive genes on a genome-wide scale.

Acetates↗
PubMed2000

A case of diffuse large B-cell lymphoma transformed from immunoglobulin A-producing marginal zone B-cell lymphoma.

We present a rare case of diffuse large B-cell lymphoma transformed from immunoglobulin (Ig) A-secreting marginal zone B-cell lymphoma. A 62-year-old woman was admitted to our hospital for examination of a disseminated pulmonary shadow. Gradual swelling of bilateral axilla and right inguinal lymph nodes were noted after admission. Histological examination of the lymph node biopsy specimen revealed the appearance of marginal zone B-cell lymphoma. The surface Ig of lymphoma cells was IgA-kappa, which coincided with the class of monoclonal Ig found in the patient's serum. The lymph node swelling and pulmonary shadow subsided, and the serum IgA level was normalized by 3 courses of systemic chemotherapy. However, after 4 courses of treatment, new tumor lesions at the right chest wall and left arm progressively became apparent. The biopsy specimen of the tumor showed a feature of diffuse large B-cell lymphoma. Despite intensive chemotherapy, the patient died of spreading tumor burden into the central nervous system.

Cell Transformation, Neoplastic↗
PubMed2000

Coloanal anastomosis in surgery for rectal cancer.

The definition of coloanal anastomosis should be based on anatomy of the anal canal. The anal canal is terminal portion of the digestive tract and comprises muscle tube of approximately 3 cm long with a lumen coated with several types of mucosa or epithelium. Muscle tube of the anal canal consists of two layers, inner sphincter muscle and external sphincter muscle. The former is a continuation of rectal muscle layer and the latter extends to the levator ani muscle. Colo-anal anastomosis (CACA): whole of the rectum is excised with a separation line placed just above the anal canal. An anastomosis is made between colonic cut end and upper limit of the anal canal. Colo-anus anastomosis in a narrow sense (CAA): rectum is excised with a bit of upper part of the anal canal. Then an anastomosis is made inside the anal canal.

Anal Canal↗
PubMed1999

Nerve growth factor promoter driven neurotrophin-3 overexpression in the mouse and the protective effect of transgene on age-related behavioral deficits.

To clarify the biological function of neurotrophin-3 (NT-3) at the postnatal stage, we created a line of transgenic mice overexpressing NT-3 under the control of the mouse nerve growth factor gene promoter. Transgenic mice showed high-level NT-3 expression in the hippocampus and several tissues. We performed behavioral tests in young-adult (7-months-old) and aged (25-months-old) mice. Although aged non-transgenic mice exhibited spatial learning impairments in the Morris water maze, overexpression of NT-3 protected against these age-dependent spatial learning impairments in mice.

Aging↗
PubMed1999

Cloning of chlorophyllase, the key enzyme in chlorophyll degradation: finding of a lipase motif and the induction by methyl jasmonate.

Chlorophyllase (Chlase) is the first enzyme involved in chlorophyll (Chl) degradation and catalyzes the hydrolysis of ester bond to yield chlorophyllide and phytol. In the present study, we isolated the Chlase cDNA. We synthesized degenerate oligo DNA probes based on the internal amino acid sequences of purified Chlase from Chenopodium album, screened the C. album cDNA library, and cloned a cDNA (CaCLH, C. album chlorophyll-chlorophyllido hydrolase). The deduced amino acid sequence (347 aa residues) had a lipase motif overlapping with an ATP/GTP-binding motif (P-loop). CaCLH possibly was localized in the extraplastidic part of the cell, because a putative signal sequence for endoplasmic reticulum is at the N terminus. The amino acid sequence shared 37% identity with a function-unknown gene whose mRNA is inducible by coronatine and methyl jasmonate (MeJA) in Arabidopsis thaliana (AtCLH1). We expressed the gene products of AtCLH1 and of CaCLH in Escherichia coli, and they similarly exhibited Chlase activity. Moreover, we isolated another full-length cDNA based on an Arabidopsis genomic fragment and expressed it in E. coli, demonstrating the presence of the second Arabidopsis CLH gene (AtCLH2). No typical feature of signal sequence was identified in AtCLH1, whereas AtCLH2 had a typical signal sequence for chloroplast. AtCLH1 mRNA was induced rapidly by a treatment of MeJA, which is known to promote senescence and Chl degradation in plants, and a high mRNA level was maintained up to 9 h. AtCLH2, however, did not respond to MeJA.

Acetates↗
PubMed1999

Magnesium insertion by magnesium chelatase in the biosynthesis of zinc bacteriochlorophyll a in an aerobic acidophilic bacterium Acidiphilium rubrum.

To elucidate the mechanism for formation of zinc-containing bacteriochlorophyll a in the photosynthetic bacterium Acidiphilium rubrum, we isolated homologs of magnesium chelatase subunits (bchI, -D, and -H). A. rubrum bchI and -H were encoded by single genes located on the clusters bchP-orf168-bchI-bchD-orf320-crtI and bchF-N-B-H-L as in Rhodobacter capsulatus, respectively. The deduced sequences of A. rubrum bchI, -D, and -H had overall identities of 59. 8, 40.5, and 50.7% to those from Rba. capsulatus, respectively. When these genes were introduced into bchI, bchD, and bchH mutants of Rba. capsulatus for functional complementation, all mutants were complemented with concomitant synthesis of bacteriochlorophyll a. Analyses of bacteriochlorophyll intermediates showed that A. rubrum cells accumulate magnesium protoporphyrin IX monomethyl ester without detectable accumulation of zinc protoporphyrin IX or its monomethyl ester. These results indicate that a single set of magnesium chelatase homologs in A. rubrum catalyzes the insertion of only Mg(2+) into protoporphyrin IX to yield magnesium protoporphyrin IX monomethyl ester. Consequently, it is most likely that zinc-containing bacteriochlorophyll a is formed by a substitution of Zn(2+) for Mg(2+) at a step in the bacteriochlorophyll biosynthesis after formation of magnesium protoporphyrin IX monomethyl ester.

Acetobacteraceae↗
PubMed1999

High dose chemotherapy for refractory urothelial carcinoma supported by peripheral blood stem cell transplantation.

BACKGROUND: Chemotherapy with methotrexate (MTX), vinblastine, doxorubicin, and cisplatin (M-VAC) is reported to be the most effective regimen for urothelial carcinoma. Complete response (CR) is observed in many cases. However, to the authors' knowledge there is no alternative therapy for nonresponders. Thus, the authors attempted high dose chemotherapy (HDC) supported with peripheral blood stem cells (PBSCs) collected after a modified method of mobilization to yield sufficient PBSCs for the HDC regimen employed. METHODS: PBSCs were collected from ten patients, all of whom had recurrent and/or refractory transitional cell carcinoma. They were treated by modified M-VAC (with pirarubicin in place of doxorubicin) for PBSC harvest. Seven micrograms per kilogram of body weight of granulocyte-colony stimulating factor was injected subcutaneously daily from Day 10 of treatment to the end of the harvest. Harvest was initiated from the day when peripheral leukocyte counts exceeded 10,000/microL and usually continued for 3 consecutive days. Each patient received two courses of HDC. Therefore, 20 courses of HDC comprised of 300 mg/body of MTX, 1500 mg/m(2) of etoposide, and high dose carboplatin (CBDCA) were given to these 10 patients. The dose of CBDCA was determined by the formula of Calvert et al., in which the target area under the concentration versus time curve of CBDCA was adjusted to 21 mg. minute/mL. RESULTS: Sufficient PBSCs were collected for myeloablative chemotherapy in all patients. No patient responded to the treatment with modified M-VAC. Response to HDC was observed in nine of ten patients. CR was achieved in seven patients and a partial response was noted in two patients. A patient with multiple bone metastases showed no response. All patients rapidly recovered after PBSC transplantation. No patient died of treatment-related toxicity. CONCLUSIONS: HDC supported by PBSC transplantation was found to have a remarkable response against refractory urothelial carcinoma, for which there was no alternative therapy.

Aged↗
PubMed1999

Characterization of cis-elements required for the transcriptional activation of the rae28/mph1 gene in F9 cells.

The rae28/mph1 gene is the mouse homologue of the Drosophila polyhomeotic gene, which plays a crucial role in the maintenance of the transcriptional repression state of Hox genes. Expression of the rae28/mph1 gene is induced during retinoic acid (RA)-mediated differentiation of embryonal carcinoma F9 cells. By transient-transfection experiments, we identified a pair of inverted differentiation response sequences (DRS(s)) in the 5' flanking region. Each of the DRS(s) contained the consensus sequence [5'-CCTCCCCXCXGCCCCCTCCXCXC-3'], which is also conserved in the human counterpart of the rae28/mph1 gene. Electrophoretic mobility shift assay and DNase I foot printing with nuclear extracts derived from F9 cells demonstrated the presence of novel DNA-binding factors which specifically interact with DRS(s). Nucleotide substitutions in the 3' DRS abrogated the factor binding and the transcriptional activation, suggesting that DRS(s) and DRS-binding factors play an important role in the transcriptional regulation of the rae28/mph1 gene.

Animals↗
PubMed1999

Preparation of uniformly sized polymeric separation media potentially suitable for small-scale high-performance liquid chromatography and/or capillary electrochromatography.

Uniformly sized polymer particles were prepared by either a two-step swelling and polymerization method or a Shirasu porous glass (SPG) emulsification technique to compare their suitability as a uniformly sized packing material for small-scale high-performance liquid chromatography (HPLC) or capillary electrochromatography (CEC). The SPG emulsification technique afforded slightly worse size uniformity compared to the two-step swelling and polymerization technique. However, fairly nice spherical shapes with reproducible outward appearance and internal pore size distribution were obtained for both of 3- or 6-micron sized particles. On the other hand, the two-step swelling and polymerization method afforded broken particles with quite different outward appearances due to the polymeric porogen effects of seed polymer utilized as the shape template. In HPLC, the column packed with the 3-micron particles prepared with the SPG emulsification technique proved to have a fairly high column efficiency with good column stability, as assessed under repeated use in gradient elution. On the other hand, the column packed with the packing material obtained through the two-step swelling and polymerization method showed much poorer column stability, while initial column efficiency was compatible to that obtained using the SPG emulsification method. In addition, the packing material prepared with the SPG emulsification technique could be modified with ion-exchangeable monomers and showed fairly good column efficiency in the CEC mode.

Chromatography, High Pressure Liquid↗
PubMed1999

Comparison of intrinsic activities of the putative sphingosine 1-phosphate receptor subtypes to regulate several signaling pathways in their cDNA-transfected Chinese hamster ovary cells.

We examined the actions of sphingosine 1-phosphate (S1P) on signaling pathways in Chinese hamster ovary cells transfected with putative S1P receptor subtypes, i.e. Edg-1, AGR16/H218 (Edg-5), and Edg-3. Among these receptor-transfected cells, there was no significant difference in the expressing numbers of the S1P receptors and their affinities to S1P, which were estimated by [(3)H]S1P binding to the cells. In vector-transfected cells, S1P slightly increased cytosolic Ca(2+) concentration ([Ca(2+)](i)) in association with inositol phosphate production, reflecting phospholipase C activation; the S1P-induced actions were markedly enhanced in the Edg-3-transfected cells and moderately so in the AGR16-transfected cells. In comparison with vector-transfected cells, the S1P-induced [Ca(2+)](i) increase was also slightly enhanced in the Edg-1-transfected cells. In all cases, the inositol phosphate and Ca(2+) responses to S1P were partially inhibited by pertussis toxin (PTX). S1P also significantly increased cAMP content in a PTX-insensitive manner in all the transfected cells; the rank order of their intrinsic activity of S1P receptor subtypes was AGR16 > Edg-3 > Edg-1. In the presence of forskolin, however, S1P significantly inhibited cAMP accumulation at a lower concentration (1-100 nM) of S1P in a manner sensitive to PTX in the Edg-1-transfected cells but not in either the Edg-3 or AGR16-transfected cells. As for cell migration activity evaluated by cell number across the filter of blind Boyden chamber, Edg-1 and Edg-3 were equally potent, but AGR16 was ineffective. Thus, S1P receptors may couple to both PTX-sensitive and -insensitive G-proteins, resulting in the selective regulation of the phospholipase C-Ca(2+) system, adenylyl cyclase-cAMP system, and cell migration activity, according to the receptor subtype.

Adenylate Cyclase Toxin↗
PubMed1999

Cloning, expression of the psbU gene, and functional studies of the recombinant 12-kDa protein of photosystem II from a red alga Cyanidium caldarium.

The encoding extrinsic 12-kDa protein of oxygen-evolving PS II complex from a red alga, Cyanidium caldarium, was cloned and sequenced by means of PCR and a rapid amplification of cDNA ends (RACE) procedure. The gene encodes a putative polypeptide of 154 amino acids with a calculated molecular mass of 16,714 Da. The full sequence of the protein includes two characteristic transit peptides, one for transfer across the chloroplast envelope and another for targeting into the thylakoid lumen. This indicates that the protein is encoded in the nuclear genome. The mature protein consists of 93 amino acids with a calculated molecular mass of 10,513 Da. The cloned gene was successfully expressed in Escherichia coli and the resulting protein was purified, reconstituted to CaCl2-washed PS II complex together with the other extrinsic proteins of 33 and 20 kDa and cyt c-550. The recombinant 12-kDa protein bound completely with the PSII complex, which resulted in a restoration of oxygen evolution equal to the level achieved by binding of the native 12-kDa protein.

Amino Acid Sequence↗
PubMed1999

Isolation of MHC class I-restricted tumor antigen peptide and its precursors associated with heat shock proteins hsp70, hsp90, and gp96.

We have previously demonstrated that vaccination with heat shock proteins hsp70, hsp90, and gp96 elicits specific immunity against the tumor from which the hsps were purified. Although the association of tumor Ag peptides with these hsps have been suggested, the identification of the peptides or their precursors stripped from the hsps remained to be resolved. We show in this report that an Ld-restricted cytotoxic T lymphocyte epitope of a mouse leukemia RLmale symbol1 and its precursors are associated with the chaperones hsp90 and hsp70 in the cytosol and gp96 in the lumen of the endoplasmic reticulum. Hsp70 was associated with only final sized octamer, while hsp90 was found to associate with the octamer and two distinct precursor peptides. The gp96 was associated with the octamer and one of the two precursors. Thus, each of the hsps bound a distinct set of peptides. Our results have demonstrated for the first time that the hsps associate not only with final sized tumor Ag peptide but also with its precursors. The implication of this evidence is also discussed in terms of the roles of hsps in MHC class I Ag processing/presentation.

Animals↗