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Biomedical subjects

H Uchiyama

Publications and source records attributed to H Uchiyama.

At least 127 records · Page 7Linked to original sources
PubMed1994

Involvement of serum response element in okadaic acid-induced EGR-1 transcription in human T-cells.

The present work has examined the effects of okadaic acid, an inhibitor of serine/threonine protein phosphatase, PP-1 and PP-2A, on the regulation of EGR-1 gene expression in normal peripheral blood T- and Jurkat cells. The results demonstrate that okadaic acid treatment is associated with a transient induction of EGR-1 gene expression which was detectable by 30 min to 1 h and peaked at 3-6 h. EGR-1 mRNA was superinduced in cells treated with both okadaic acid and the protein synthesis inhibitor cycloheximide. The half-life of EGR-1 mRNA was similar in both control and okadaic acid-treated cells. In contrast, treatment with both okadaic acid and cycloheximide prolonged the half-life of EGR-1 transcripts. Nuclear run-on assays demonstrated that induction of EGR-1 gene expression by okadaic acid is controlled at least in part by a transcriptional mechanism. Transient expression assays with EGR-1 promotor fragments linked to the chloramphenicol acetyltransferase gene demonstrate that okadaic acid-induced EGR-1 transcription is conferred by the 5' most distal CArG box, CC (AT)6GG, in the EGR-1 promoter. Moreover, chloramphenicol acetyltransferase activity was induced by okadaic acid when the 5' most distal CArG element was linked to the heterologous herpes simplex virus thymidine kinase promoter, and not induced with a similar heterologous construct containing a mutated CArG sequence. These studies demonstrate that okadaic acid regulates EGR-1 gene expression at the transcriptional level via the CArG element and suggest that PP-1 and PP-2A play a role in T-cell activation.

Base Sequence↗
PubMed1994

Identification of activins A, AB, and B and follistatin proteins in Xenopus embryos.

There are several lines of evidence that activin is a crucial molecule for mesoderm induction in early Xenopus embryos. However, it is not known what kind and what amounts of activin proteins exist in cleavage stage embryos. Three isoforms of activins, A, AB, and B, were demonstrated to be present at least in part as a complex with abundant follistatin, an activin-binding protein, in early Xenopus embryos (stage 1-5). These results suggest that activin stored in eggs has an important role for mesoderm induction during early Xenopus embryogenesis and that follistatin can modulate the function of activin in signaling developmental changes.

Activins↗
PubMed1994

Sperm and its soluble extract cause transient increases in intracellular calcium concentration and in membrane potential of sea urchin zygotes.

Fertilization is known to initiate a transient increase of intracellular calcium concentration and an accompanying change of membrane potential in sea urchin eggs. If the fertilization membrane and hyaline layer are removed, sperm can again enter fertilized eggs (refertilization). We have found that Ca2+ and voltage transients were repeatedly induced in fertilized eggs during refertilization. Similar changes were also obtained by external application of a soluble extract of sperm to fertilized eggs. This sperm extract caused no changes in unfertilized eggs. The active factor in the sperm extract survives heating (100 degrees C, 10 min) and incubation with pronase. Its molecular weight is less than 1300.

Animals↗
PubMed1994

Centrifugal inputs enhance responses of retinal ganglion cells in the Japanese quail without changing their spatial coding properties.

Centrifugal fibers originating in the midbrain innervate the avian retina. Stimulation of the centrifugal fibers enhances the responses of ganglion cells in the retinas of both chick and pigeon. The enhanced responses have been attributed to disinhibition, a reduction of the inhibitory surround component of the receptive fields of retinal ganglion cells. We found that stimulation of the centrifugal fibers in Japanese quail enhances the responses of retinal ganglion cells to drifting sine-wave gratings over a wide range of spatial frequencies. Our results do not support the idea that centrifugal inputs selectively influence receptive field surrounds. We also found that centrifugal inputs changed the temporal response properties of retinal ganglion cells by enhancing their responses to sine-wave gratings drifting across the retina at higher temporal frequencies (> 5 Hz). The result shows that centrifugal inputs from the midbrain can enhance responses of retinal ganglion cells without affecting the center-surround organization of their receptive fields. The centrifugal modulation of retinal responses may have a role in shifting visual attention.

Animals↗
PubMed1994

Secondary cutaneous oxalosis: cutaneous deposition of calcium oxalate dihydrate after long-term hemodialysis.

A 48-year-old Japanese man had miliary calcified papules on the distal fingers after long-term hemodialysis. The crystals in the dermis consisted of calcium oxalate, as revealed by light microscopy and scanning electron microscopy with energy-dispersive x-ray microanalysis. The calcium oxalate was in the form of a dihydrate crystal. Therefore a diagnosis of secondary cutaneous oxalosis was made. In cutaneous oxalosis that occurs as a result of hemodialysis, miliary deposits occur in the fingers, but not the toes, and are present more frequently on the palmar aspects of the fingers. This localization may result from local differences in the metabolism or concentration of calcium or oxalate, or changes in the blood circulation.

Calcium Oxalate↗
PubMed1994

Kinetics of serum cytokines in adults undergoing peripheral blood progenitor cell transplantation.

We investigated the serum cytokine levels (G-CSF, GM-CSF, IL-1 beta, IL-3 and IL-6) using an ELISA in 14 patients with haematological malignancies undergoing peripheral blood progenitor cell transplantation (PBPCT). Serum G-CSF levels in all patients rose immediately after PBPCT, then gradually decreased as the neutrophil counts began to rise. No detectable serum levels of GM-CSF or IL-1 beta were observed, but serum levels of IL-3 rose transiently immediately following PBPCT. Serum levels of IL-6 rose transiently during a fever in four patients. These observations suggest that G-CSF and IL-3 may contribute to the early haemopoietic reconstitution in PBPCT.

Adolescent↗
PubMed1994

Cell surface expression and functional significance of adhesion molecules on human myeloma-derived cell lines.

Multiple myeloma is characterized by the presence of malignant plasma cells predominantly localized in bone marrow. Our prior studies have suggested that human myeloma derived-cell lines adhere specifically to fibronectin and to bone marrow stromal cells (BMSCs) via beta 1 and beta 2 integrins as well as RGD peptide, and that tumour cell to BMSC contact triggers interleukin-6 (IL-6) secretion from BMSCs. Since IL-6 is a growth factor for myeloma, adhesion may be important in paracrine IL-6 mediated tumour cell growth. We therefore examined phenotypic expression of adhesion molecules on the U266 and IM-9 human myeloma-derived cell lines using the panel of monoclonal antibodies (MoAbs) directed at adhesion molecules submitted to the Vth International Conference on Human Leukocyte Differentiation Antigens. U266 and IM-9 myeloma cell lines express mainly CD29, CD49d, VLA-1, CD18, CD54, ICAM-2 and ICAM-3. In contrast, CD49b, VLA-3, CD49f, CD11b, VCAM-1, selectins and selectin-ligands were not expressed on these cell lines. Specific adherence of IM-9 cells to BMSC line LP101 was demonstrated which could be partially blocked by pre-incubation and culture of tumour cells with anti-beta 1 integrin, anti-beta 2 integrin, anti-CD49d, anti-VLA-5, anti-CD11a, anti-CD44 and anti-CD54 MoAbs. The combination of these MoAbs (anti-CD29, CD18, CD11a, CD49d, VLA-5, CD44, CD54, ICAM-2, ICAM-3 MoAbs) decreased but did not completely abrogate binding of IM-9 to BMSCs. Moreover, increases in IL-6 secretion from BMSCs after adherence of IM-9 cells were also partially blocked by these MoAbs. These findings suggest that multiple adhesion pathways may mediate adherence of myeloma cell lines to BMSCs, localizing tumour cells in the marrow microenvironment and triggering IL-6 secretion by BMSCs which may augment tumour cell growth.

Antibodies, Monoclonal↗
PubMed1994

Factors affecting the efficiency of peripheral blood stem cell collection in children treated with chemotherapy and G-CSF.

This retrospective study attempts to clarify the optimal timing for peripheral blood stem cell (PBSC) collection after conventional chemotherapy followed by granulocyte-colony stimulating factor (G-CSF) administration. Leukapheresis was performed 32 times in nine children with various cancers during bone marrow recovery phase following transient pancytopenia after chemotherapy. (On two occasions, leukapheresis was excluded because many leukemic blasts were included). When the number of white blood cells (WBC) exceeded 1.8 x 10(10)/L after administration of G-CSF (200 micrograms/m2, continuous infusion), many more CD34+ cells were contained in the collected peripheral mononuclear cells (P > 0.02) and a sufficient number of PBSC for transplantation (> or = 10 x 10(8) CD34+ cells/kg) was obtained after one run in 15 of 17 leukapheresis sessions. In contrast, sufficient PBSC were obtained only in one of 13 runs of leukapheresis when the number of WBC was < 1.8 x 10(10)/L. The number of WBC on the day when PBSC were collected correlated with collected nuclear cell number (r = 0.60), but not with the CD34+ cell ratio. The ratio was higher only when both platelets and reticulocytes increased in parallel with WBC. We conclude that sufficient PBSC collection is possible after conventional chemotherapy using G-CSF, when hematopoietic recovery is parallel, without the use of high-dose chemotherapy.

Antigens, CD↗
PubMed1994

Cesium Accumulation and Growth Characteristics of Rhodococcus erythropolis CS98 and Rhodococcus sp. Strain CS402.

Growth and cesium accumulation characteristics of two cesium-accumulating bacteria isolated from soils were investigated. Rhodococcus erythropolis CS98 and Rhodococcus sp. strain CS402 accumulated high levels of cesium (approximately 690 and 380 mumol/g [dry weight] of cells or 92 and 52 mg/g [dry weight] of cells, respectively) after 24 h of incubation in the presence of 0.5 mM cesium. The optimum pH for cesium uptake by both Rhodococcus strains was 8.5. Rubidium and cesium assumed part of the role of potassium in the growth of both Rhodococcus strains. Potassium and rubidium inhibited cesium accumulation by these Rhodococcus strains. It is likely that both Rhodococcus strains accumulated cesium through a potassium transport system.

Journal Article↗
PubMed1994

Peripheral blood progenitor cell transplantation estimated by three-colour (CD34, HLA-DR, CD33) flow cytometry.

The relationships between transfused cell number of CD34+ cell subpopulations divided by HLA-DR and CD33 antibodies and hematopoietic recovery patterns after peripheral blood progenitor cell transplantation (PBPCT) subsequent to myeloablative chemoradiotherapy were investigated in 14 children with cancer. Both logarithm of transfused CD34+ cell number/10(6)/kg and logarithm of transfused cell number/10(6)/kg of the CD34+HLA-DR+CD33+ subpopulation, which is supposed to be myeloid-committed cells, were correlated with myeloid recovery after PBSCT, though they were not correlated with erythroid or platelets recovery. On the other hand, logarithm of transfused cell number/10(6)/kg of CD34 + HLA-DR-CD33-subpopulation, which is supposed to be immature progenitor cells, was not correlated with myeloid recovery but correlated with erythroid recovery and platelet recovery. These results suggested that rapid myelopoiesis after PBPCT occurs following transfusion of sufficient numbers of myeloid-committed cells and complete hematopoietic reconstitution occurs after transfusion of sufficient numbers of immature hematopoietic progenitor cells.

Adolescent↗
PubMed1994

Survival and impact of genetically engineered Pseudomonas putida harboring mercury resistance gene in soil microcosms.

The survival of genetically engineered and wild-type Pseudomonas putida PpY101, that contained a recombinant plasmid pSR134 conferring mercury resistance, were monitored in andosol and sand microcosms. The survival of genetically engineered and wild-type P. putida was not significantly different in andosol. The population change of the two strains was dissimilar in andosol and sand. The survival of genetically engineered and wild-type P. putida strains was affected by the water content of andosol, and increased with the increment of the water content. The impact of the addition of genetically engineered and wild-type P. putida strains on indigenous bacteria and fungi was examined. Inoculation of both strains had no apparent effect on the density of indigenous microorganisms.

Drug Resistance, Microbial↗
PubMed1994

Transformation of Pseudomonas putida by electroporation.

The optimum electrotransformation conditions were determined for Pseudomonas putida PpY101 with plasmid pSUP104 (9.5 kb) and pSR134 (18.6 kb). Field strength was a very important parameter for electrotransformation efficiency. Optimum efficiencies (1.1 x 10(5) transformants/micrograms DNA) with pSUP104 and pSR134 were obtained at a field strength of 12.5 kV/cm, a time constant of about 4.5 ms (resistance setting of 200 ohms), a supercoiled DNA concentration of 100 ng/ml, and a cell concentration of 10(9)/ml. Because the efficiency obtained is high enough, electrotransformation is useful for the direct cloning of P. putida PpY101. No significant relationship between plasmid size and electrotransformation efficiency was observed. These efficiencies were about 4.5 times higher than those using the MgCl2 method. Under these conditions, electrotransformation efficiencies of relaxed plasmid DNA treated with topoisomerase I and that linearized by EcoRI digestion were high.

Biotechnology↗
PubMed1994

Intracoronary acetylcholine-induced prolongation of the QT interval and Torsade des Pointes in long QT interval syndrome.

A 75-year-old female had syncopal episodes from Torsade des Pointes (TdP). Her electrocardiogram showed a prolonged QT interval which was not associated with electrolyte imbalances or drug therapy. Similar electrocardiographic abnormalities were found in three family members. Electrophysiologic study showed a mildly prolonged effective refractory period of 260-290 msec, but no tachyarrhythmia was induced. Coronary arteriography was normal but intracoronary acetylcholine unexpectedly induced a prolongation of the QT interval and TdP. Direct action of acetylcholine on the ventricular muscle was suggested.

Acetylcholine↗
PubMed1994

Effect of granulocyte colony-stimulating factor on hematopoietic recovery after peripheral blood progenitor cell transplantation.

To examine the effect of granulocyte colony-stimulating factor (G-CSF) on hematopoietic recovery after high-dose chemotherapy and peripheral blood progenitor cell transplantation (PBPCT), 20 patients with hematologic malignancies were divided into two groups. One group was given G-CSF at a daily dose of 50 micrograms/m2 subcutaneously, the other received no G-CSF. Neutrophil recovery was accelerated in the G-CSF treated patients and exceeded 0.5 x 10(9)/l at a median of 10 days post-PBPCT compared with 14 days in the control group (p < 0.01). This reduction led to a decrease in antibiotic use and a trend toward fewer febrile days in the G-CSF treated group.

Adolescent↗
PubMed1993

Adhesion of human myeloma-derived cell lines to bone marrow stromal cells stimulates interleukin-6 secretion.

Previous studies show that human myeloma-derived cell lines specifically adhere to fibronectin (FN) through very late antigen-4 (VLA-4; alpha 4 beta 1 integrin complex) and RGD-peptide mechanisms, which may contribute to the localization of tumor cells in bone marrow (BM). In these studies, we characterized the adhesion of myeloma-derived cell lines to both normal and myeloma BM stromal cells (BMSCs) and the effect of adhesion on DNA synthesis. Because interleukin-6 (IL-6) plays an important role in the pathogenesis of multiple myeloma, we also examined the effects of tumor cell adhesion on IL-6 secretion by BMSCs. In 51chromium binding assays, the U266, ARH-77, and IM-9 cell lines showed 52% +/- 12%, 55% +/- 6%, and 47% +/- 7% specific adherence, respectively, to normal BMSCs and 74% +/- 4%, 60% +/- 3%, and 61% +/- 6% specific adherence, respectively, to myeloma BMSCs. In contrast, only 12% to 13% specific binding of HS-Sultan cells to BMSCs was noted. The binding of myeloma cells to BMSCs was partially blocked with anti-beta 1 monoclonal antibody (MoAb), anti-beta 2 integrin MoAb, and excess RGD peptide, suggesting multiple mechanisms for the adhesion of myeloma cell lines to BMSCs. Binding of cell lines to FN or myeloma BMSCs did not affect cell line proliferation; however, adhesion of myeloma cell lines to normal BMSCs decreased DNA synthesis, ie, stimulation indices are 0.1 +/- 0.04, 0.2 +/- 0.1, 0.2 +/- 0.07, and 0.1 +/- 0.06 for the adherent non-IL-6-dependent U266, ARH-77, HS-Sultan, and IM-9 cells, respectively (n = 5, P < .01). In contrast, adherence of IL-6-dependent B9 cells increased their proliferation (stimulation index, 3.2 +/- 0.7). Significant (twofold to eightfold) increases in IL-6 secretion were evident in cell line-adherent (> or = 12 hours) normal and myeloma BMSC cultures. Paraformaldehyde fixation of BMSCs before adhesion completely abrogated IL-6 secretion, suggesting that IL-6 secretion was triggered in BMSCs rather than in cell lines. Partial blocking of cell line adhesion to BMSCs, using anti-beta 1 integrin and anti-beta 2 integrin MoAbs and RGD peptide, also partially blocked the triggering of IL-6 secretion by BMSCs. When cell lines were placed in Transwell inserts and then cultured with either normal or myeloma BMSCs, permitting juxtaposition without cell to cell contact between myeloma cell lines and BMSCs, no increase in IL-6 secretion was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1993

Frequency of presumed reentry with an excitable gap in sustained ventricular tachycardia unassociated with coronary artery disease.

In sustained ventricular tachycardia (VT) unrelated to coronary artery disease, the incidence of reentry with an excitable gap was examined, and rapid pacing was performed to entrain VT in 48 episodes in 42 consecutive patients. Coronary artery disease was excluded by coronary arteriography. The underlying heart diseases were postoperative congenital heart diseases (n = 5), dilated (n = 7) or hypertrophic (n = 4) cardiomyopathy, arrhythmogenic right ventricular dysplasia (n = 6) and miscellaneous heart diseases (n = 5), as well as no demonstrable heart disease (n = 15) in which 8 patients had verapamil-responsive VT. Except for 1 patient with hypertrophic cardiomyopathy, 48 morphologically distinct monomorphic sustained VTs were induced. Twenty-five VTs showed right bundle branch block morphology and 23 left bundle branch block morphology, and VT was entrained in 84 and 96%, respectively. The overall incidence of the entrainment was 89.6% (43 of 48 monomorphic VTs), and the frequency of the ability to entrain VT ranged between 33.3 and 100% in the subgroups. The lowest frequency was found in hypertrophic cardiomyopathy. In conclusion, most inducible monomorphic sustained VT unassociated with coronary artery disease was presumed to be reentry with an excitable gap.

Adolescent↗
PubMed1993

Target cells for the isthmo-optic fibers in the retina of the Japanese quail.

The isthmo-optic nucleus (ION) is the major origin of the centrifugal fibers projecting to the avian retina. The retinopetal fibers from the ION were labeled with biocytin and examined light- and electron-microscopically in the Japanese quail. The terminals were seen on cell bodies in the inner part of the inner nuclear layer. These neurons innervated with the isthmo-optic fibers appear to constitute a separate population different from the 'ordinary' amacrine cells.

Animals↗