Overexpression of tissue factor pathway inhibitor in aortic smooth muscle cells inhibits cell migration induced by tissue factor/factor VIIa complex.
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Animals↗
Biomedical subjects
Y Asada
Publications and source records attributed to Y Asada.
Novel distribution of adrenomedullin-immunoreactive cells in human tissues.
Adrenomedullin (AM) is a novel hypotensive and vasodilator peptide. We previously examined the localization of AM in human, rat, and porcine tissues using a polyclonal antibody against synthetic human AM[40-52]. We demonstrated that AM is widely distributed in the endocrine and neuroendocrine systems, but not in the heart, kidney, or blood vessels, although high levels of AM mRNA were detected in the latter tissues. In this study, we further investigated the distribution of AM by using two newly developed monoclonal antibodies against synthetic human AM peptides, [12-25] and [46-52]. AM immunoreactivity was observed in cardiac myocytes, vascular smooth muscle cells, endothelial cells, and renal distal and collecting tubules. In addition, AM-immunoreactive (IR) cells were found in mucosal and glandular epithelia of the digestive, respiratory, and reproductive systems, as well as the endocrine and neuroendocrine systems. These findings indicate that AM-IR cells are more widely distributed in human tissues and suggest that AM might play multiple biological roles in humans.
Adrenomedullin↗
Minoxidil increases 17 beta-hydroxysteroid dehydrogenase and 5 alpha-reductase activity of cultured human dermal papilla cells from balding scalp.
Minoxidil is known to induce hair growth in male pattern baldness, for which development androgen plays a central role. We studied the effect of minoxidil on testosterone metabolism by cultured dermal papilla cells from balding or nonbalding scalp and dermal fibroblasts. In all three groups, 17beta-hydroxysteroid dehydrogenase activity was much higher than 5alpha-reductase activity. Minoxidil increased 17beta-hydroxysteroid dehydrogenase activity by nearly 40% (P < 0.001) in dermal papilla cells of balding scalp, whereas the effect was less marked in dermal papilla cells from nonbalding scalp and dermal fibroblasts. 5alpha-Reductase activity was also slightly increased by minoxidil in dermal papilla cells from balding scalp. Again, the effect on 5alpha-reductase activity was insignificant in the other two groups of cells. Whether such modification of testosterone metabolism in dermal papilla cells of balding scalp by minoxidil is related to its therapeutic effect remains unknown.
17-Hydroxysteroid Dehydrogenases↗
Simulation of the daily sunlight illumination pattern for bacterial photo-hydrogen production.
Methods of illumination to simulate the daily sunlight irradiation pattern were studied in relation to photohydrogen production using the photosynthetic bacterium Rhodobacter sphaeroides RV. Three illumination patterns were compared, in which the light intensity was changed in 1, 3, or 6 steps. As a control, outdoor experiments were also carried out over a 3-d period in Tsukuba, August 1996. Outdoors, hydrogen production by Rba. sphaeroides RV was dependent on the sunlight intensity: the total volume of hydrogen produced per day varied from 14 to 28 l.m(-2), while the total light energy ranged from 5.5 to 6.4 kWh.m(-2). d(-1). The maximum hydrogen production rate was 2.8 l.m(-2).h(-1) under a 4.5-cm light path and the average light energy conversion efficiency was 1.1%. Indoors, the hydrogen production rate was found to be independent of the mode of illumination among the three patterns employed. The maximum hydrogen production rate was 3.3 l.m(-2).h(-1) with a light energy conversion efficiency of 1.0%, and it was concluded that the single-step illumination method provides an appropriate simulation of sunlight. Saturation of hydrogen production occurs during high light intensity around noon and this plays a key role in the simulation.
Journal Article↗
Entrapment of Rhodobacter sphaeroides RV in cationic polymer/agar gels for hydrogen production in the presence of NH4+.
Cationic polyelectrolytes (chitosan, poly-L-lysine (PLL), polyethyleneimine (PEI) and trimethylammonium glycol chitosan iodide (TGCI)) were used to entrap anoxygenic phototrophic bacteria in order to prevent the inhibitory effect of NH4+ on hydrogen production. When combined with agar gel, chitosan and PLL demonstrated no obvious repressive effect on hydrogen production by Rhodobacter sphaeroides under light-anaerobic conditions with lactate and glutamate as the carbon and nitrogen sources, respectively. On the other hand, both PEI and TGCI exerted a detrimental effect on hydrogen production under these conditions. Hydrogen production in the presence of NH4+ by the bacteria entrapped in the complex gel containing chitosan and agar improved considerably compared to that in the control containing only agar. Evidence shows that chitosan improves the hydrogen production via various effects. Diffusion tests demonstrated that the addition of chitosan increased to some extent the resistance to the diffusion of positively charged NH4+, but had no effect on negatively charged lactate. A buffer effect in the complex gels was also revealed.
Journal Article↗
Enhanced hydrogen production by a mutant of Rhodobacter sphaeroides having an altered light-harvesting system.
A stable mutant of the photosynthetic bacterium Rhodobacter sphaeroides with an altered light-harvesting (LH) system (P3 mutant) was obtained by UV irradiation and characterized. The mutant exhibited a 2.7-fold decrease in the core antennal (LH1) content and 1.6-fold increase in peripheral antennal (LH2) content compared to the wild-type strain. The H2 evolution rates in the P3 mutant under 800- and 850-nm light, corresponding to the absorption maxima of LH2, were 1.5 times higher than in the wild-type strain. The wild-type absorption spectrum was restored in the P3 mutant when a 1.1-kb PCR-amplified fragment containing the puf promoter and pufQBA genes was ligated into a pRK-415 derivative and introduced into it. The transformant showed lower H2 production rates at 800 and 850 nm than the P3 strain carrying the control plasmid, indicating that the accelerated H2 production in the P3 mutant was a result of alterations in the LH system.
Journal Article↗
Immobilization of P450 monooxygenase and chloroplast for use in light-driven bioreactors.
P450 monooxygenases exhibit great potential for application to bioreactors for the decomposition of various hydrophobic chemicals including pollutant compounds. P450-containing microsomes were immobilized in spinach chloroplasts for use in light-driven bioreactors. We tested three methods (entrapment, adsorption and cross-linking) to immobilize chloroplasts and yeast microsomes containing a genetically engineered fusion enzyme between rat P450 1A1 and yeast P450 reductase. Entrapment in agarose gave the best activity for the conversion of 7-ethoxycoumarin to 7-hydroxycoumarin under illumination of 6200 lx. We then tested three light-driven bioreactors (two column-type and one batch-type reactors developed) using the immobilized gels. A two-phase column-type reactor with separately immobilized microsomes and chloroplasts showed a higher conversion rate than a reactor with co-immobilization of both components. The reactor showed a turnover rate of 6.32 mol product/mol P450/min after a 40-min run, and 2.49 after a 180-min run. These turnover rates are higher than the values reported by others using immobilized microsomal P450s.
Journal Article↗
Photobiological hydrogen production.
The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase via cyanobacterial ferredoxin was demonstrated in the presence of light. Genetic transformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum was successful; the active enzyme was expressed in PCC7942. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Coculture of Rhodobacter and Clostriudium was applied for hydrogen production from glucose. A mutant strain of Rhodobacter sphaeroides RV whose light-harvesting proteins were altered was obtained by UV irradiation. Hydrogen productivity by the mutant was improved when irradiated with monochromatic light of some wavelengths. The development of photobioreactors for hydrogen production is also reviewed.
Journal Article↗
In vitro and in vivo coupling of Thiocapsa hydrogenase with cyanobacterial and algal electron mediators.
H2 activation by the oxygen-tolerant hydrogenase from the purple sulfur bacterium Thiocapsa roseopersicina, using electron mediators of cyanobacterial and algal origin, has been demonstrated. Ferredoxins, either from the cyanobacterium Synechococcus PCC7942 or the green alga Scenedesmus obliquus, are capable of providing electrons for hydrogenase-mediated H2 evolution. The high-potential cytochrome c6 from Synechococcus PCC7942 proved to be capable of accepting electrons derived from hydrogenase-mediated H2 oxidation. In subsequent experiments, Thiocapsa hydrogenase was introduced into the cells of Synechococcus PCC7942 by electroporation, for enhanced H2 production.
Journal Article↗
Susceptibility to testicular germ-cell tumours in a 129.MOLF-Chr 19 chromosome substitution strain.
The identification of genes that control susceptibility to testicular germ-cell tumours (TGCTs), the most common cancer affecting young men, has been difficult. In laboratory mice, TGCTs arise from primordial germ cells in only the 129 inbred strains, and susceptibility is under multigenic control. The spontaneously arising mutation Ter (ref. 5) on mouse chromosome 18 (Refs 6,7) increases TGCT frequency on a 129/Sv background. We originally used Ter in genetic crosses to identify loci that control tumorigenesis. A genome scan of tumour-bearing progeny from backcrosses between the 129/Sv-Ter/+ and MOLF/Ei strains provided modest evidence that MOLF-derived alleles on chromosome 19 enhance development of bilateral TGCTs (ref. 9). To obtain independent evidence for linkage to the MOLF chromosome, we made an autosomal chromosome substitution strain (CSS; or 'consomic strain') in which chromosome 19 of 129/Sv+/+ was replaced by its MOLF-derived homologue. The unusually high frequency of TGCTs in this CSS (even in the absence of the Ter mutation) provides evidence confirming the genome survey results, identifies linkage for a naturally occurring strain variant allele that confers susceptibility to TGCTs and illustrates the power of CSSs in complex trait analysis.
Alleles↗
Hepatic stellate cells (Ito cells) in veno-occlusive disease of the liver after allogeneic bone marrow transplantation.
AIMS: To evaluate the role of activated hepatic stellate cells (HSCs) in hepatic veno-occlusive disease (VOD) after bone marrow transcription (BMT), we studied the distribution and area of activated HSCs by immunohistochemistry for alpha-smooth muscle actin (SMA). METHODS AND RESULTS: We examined the liver of seven autopsy cases with hepatic VOD or without VOD after allogeneic BMT and five autopsy cases without liver disease as a control both microscopically and immunohistochemically. In normal liver tissues, SMA-positive cells were observed around the central veins, while they were more frequently noted along the sinusoidal walls as well as around the central veins in liver tissues with or without VOD after BMT. The area of activated HSCs increased significantly in zones 1 and 2, and more prominently in zone 3 of the liver tissues after BMT than normal liver tissues, and was much larger in zone 3 of liver tissues with VOD. The activated HSCs were immunohistochemically negative for the regulatory contractile proteins (heavy caldesmon and calponin). CONCLUSIONS: These results indicated that the activated HSCs may play an important role in sinusoidal fibrosis and luminal narrowing or occlusion of the central veins in VOD after BMT.
Actins↗
Cell density of adrenomedullin-immunoreactive cells in the gastric endocrine cells decreases in antral atrophic gastritis.
AIMS: Adrenomedullin (AM) is a novel hypotensive and vasorelaxing peptide recently isolated from human phaeochromocytoma tissue, and is widely distributed in various organs. In this study we examined the localization of AM-immunoreactive (IR) cells in the gastric mucosa and AM-IR cell density in antral atrophic gastritis. METHODS AND RESULTS: Gastric mucosal tissues were taken from the gastric body and antral mucosa of 52 patients (27 men, 25 women; mean age 56.0 (range 20-86) years). Immunohistochemical analysis revealed that AM-IR cells were present in the pyloric glands, but not in the fundic glands, and that AM-IR cells were stained positively for chromogranin A and gastrin. The percentage of AM-IR cells vs chromogranin A- and gastrin-IR cells was 42 and 56%, respectively. The number of AM-IR cells decreased with the progression of severity of atrophic changes in the pyloric gland, and also of mononuclear cell infiltration. There was no correlation between the number of AM-IR cells and the degree of neutrophilic infiltration. Similar findings were also obtained for gastrin-IR cells. CONCLUSION: AM-IR cells are present in the endocrine cells including gastrin-IR cells in the pyloric glands. These results suggest that AM may contribute to gastrin secretion in the pyloric glands.
Adrenomedullin↗
The mRNA for protease nexin-1 is expressed in human dermal papilla cells and its level is affected by androgen.
Protease nexin-1, an inhibitor of serine proteases, plays important parts in the regulation of the growth, differentiation, and death of cells by modulating proteolytic activity. The mRNA for protease nexin-1 accumulates in rat dermal papilla cells in a hair cycle-dependent fashion and its levels are well correlated with the ability of dermal papilla cells to support hair growth. In an attempt to characterize the potential role of protease nexin-1 as a modulator of hair growth in humans, we investigated the steady-state level of protease nexin-1 mRNA in cultured human dermal papilla cells using a semiquantitative technique that involved reverse transcription and polymerase chain reaction, as well as the localization of this mRNA in vivo using dissected hair follicles. Protease nexin-1 mRNA was expressed in all dermal papilla cells examined, and it was also identified in the lower part of the connective tissue sheath. Moreover, we found that levels of protease nexin-1 mRNA were depressed by dihydrotestosterone, the most potent androgen, in cultured dermal papilla cells obtained from balding scalp. Our results suggest that protease nexin-1 might be a key molecule in the control of hair growth in humans and, moreover, that the androgen-mediated downregulation of the synthesis of protease nexin-1 might be associated with the progression of male-pattern baldness.
Adult↗
Invasion of the lacrimal system by basal cell carcinoma.
BACKGROUND: The rate of recurrence of basal cell carcinoma (BCC) in the periorbital region is higher than that in other areas because of the spread of the tumor along barrier structures. OBJECTIVE: A better understanding of the biological behavior of BCC in this area, in particular as it relates to the lacrimal system, should improve the outcome of surgery. METHODS: A study was made of two cases of BCC that developed in the periorbital region and invaded the lacrimal system. RESULTS: The tumors were found to have invaded the lacrimal system along the mucosal epithelium. Magnetic resonance imaging (MRI) did not suggest any abnormalities in this area. In one patient, the tumor had infiltrated the nasal cavity without destruction of the periorbital bone and nasal cartilage. A preoperative fiberscopic examination clearly demonstrated the involvement of the nasal cavity in this case. CONCLUSION: The lacrimal system is often invaded by BCC that originates from the periorbital region. Physicians and surgeons need to be well aware of the possibility of such aggressive infiltration by BCC.
Aged↗
Effect of rotational alignment on patellar tracking in total knee arthroplasty.
Forty-four consecutive patients (65 knees) who underwent identical condylar type total knee arthroplasty were evaluated retrospectively. In 22 of the patients (32 knees), the femoral component was set parallel to the posterior condylar axis (neutrally aligned group). In the remaining 22 patients (33 knees), it was set in an external rotation position of 3 degrees to 5 degrees relative to the axis (externally aligned group). Of the total knee arthroplasties in the neutrally aligned group, 34% required lateral release, compared with only 6% in the externally aligned group; patellar tracking in the externally aligned group was significantly better than that in the neutrally aligned group. Postoperative measurements performed using computed tomography scans showed that the mean angle between the prosthetic posterior condylar axis and the transepicondylar axis was 7.9 degrees in the neutrally aligned group and 3.2 degrees in the externally aligned group. The external rotation setting of the femoral component diminished the need for lateral retinacular release and may decrease the rate of patellofemoral complications that occur after total knee arthroplasty.
Adult↗
Inhibitory effect of erythromycin on interleukin-8 secretion from exudative cells in the nasal discharge of patients with chronic sinusitis.
OBJECTIVES: The mechanism of the efficacy of long-term low-dose macrolide therapy for chronic sinusitis is not fully understood. The authors studied the inhibitory effect of erythromycin on interleukin-8 (IL-8) secretion from exudative cells in the nasal discharge of patients with chronic sinusitis. STUDY DESIGN AND METHODS: Exudative cells in the nasal discharge were isolated from six patients with nonallergic chronic sinusitis. The cells, more than 90% of which were neutrophils, were incubated with or without erythromycin in the presence of 10 micrograms/mL of lipopolysaccharide. The IL-8 concentrations in the culture supernatants were measured by enzyme-linked immunoassay. RESULTS: The amount of secreted IL-8 in the absence of erythromycin was 682 +/- 226 pg/10(6) cells/24 h. The IL-8 secretion was significantly reduced to 66 +/- 15% and 46 +/- 13% of the control in the presence of 10(-6) and 10(-5) M of erythromycin, respectively. CONCLUSION: Erythromycin may act as a biologic modulator that inhibits IL-8 secretion from exudative cells and thereby blocks the vicious circle of neutrophil recruitment and IL-8 generation in the inflammatory site in chronic sinusitis.
Anti-Bacterial Agents↗
Purified fusion enzyme between rat cytochrome P4501A1 and yeast NADPH-cytochrome P450 oxidoreductase.
A genetically engineered fusion enzyme between rat P4501A1 and yeast P450 reductase in the microsomal fraction of the recombinant yeast AH22/pAFCR1 was purified. The purified enzyme showed a typical CO-difference spectrum of P4501A1 and a single band with an apparent molecular weight of 125,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis. This agreed with the molecular weight of 131,202 calculated from the amino acid sequence. The purified enzyme showed both 7-ethoxycoumarin o-deethylase activity and horse heart cytochrome c reductase activity in the presence of NADPH. The 7-ethoxycoumarin o-deethylase activity depended on the species of lipid used for the reconstitution of the purified fusion enzyme although the purified enzyme showed the activity without reconstitution. The purified fusion enzyme had the Km value of 26 microM for 7-ethoxycoumarin and the maximal turnover rate of 29 mol product/min/mol enzyme at 30 degrees C.
7-Alkoxycoumarin O-Dealkylase↗
A high-copy-number plasmid capable of replication in thermophilic cyanobacteria.
A 2.5 kb high-copy-number plasmid, pMA4 in thermophilic cyanobacterium Synechococcus sp. MA4 was isolated and characterized to develop a genetic engineering system for thermophilic cyanobacteria. The copy number of pMA4 was determined to be by densitometry about 350/cell. The pMA4 may be a type of rolling-circle plasmid, because a possible rep gene encoding 34 kD-protein and a consensus sequence of a double-stranded origin nick site of rolling circle plasmids were found in the pMA4 sequence. The pMA4 was electro-introduced into another thermophile, Synechococcus sp. MA19, which is the strongest poly-beta-hydroxybutyrate (PHB) accumulator in photoautotrophic organisms. The pMA4 was incorporated and retained in MA19. These results indicate that pMA4 could be developed as a useful vector for thermophilic cyanobacteria.
Amino Acid Sequence↗