Detection of nucleic acid interactions using surface plasmon resonance.
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Antigen-Antibody Reactions↗
Biomedical subjects
M Wakasa
Publications and source records attributed to M Wakasa.
Increased apoptosis rate by hyperthermochemoradiotherapy for advanced rectal cancers.
Apoptosis induced in cancer cells by ionizing radiation, hyperthermia, and 5-fluorouracil (5-FU), termed "hyperthermochemoradiotherapy" (HCR), has been well studied in vitro; however, the role of apoptosis in the tumocidal effect of HCR for primary rectal cancers has not yet been clarified. Therefore, we examined the relationship between the therapeutic effect and induction rate of histological apoptosis in 16 patients with rectal cancers after HCR. Numerous Tunel-positive apoptotic cells were found in the tumor tissue after HCR, but few were found in the tumors which had not received HCR. The histological therapeutic effect was closely correlated to the rate of apoptosis. Thus, we suggest that HCR induces a therapeutic effect mainly through apoptosis in human rectal cancers.
Administration, Rectal↗
Interaction of the basic protrusion of Escherichia coli ribonuclease HI with its substrate.
In order to determine the actual distance between the active site and the substrate binding site, termed the basic protrusion, of Escherichia coli ribonuclease HI, synthetic oligonucleotide duplexes with gradually extended overhangs were used, in which the enzymatic cleavage was restricted to a single site with 2'-O-methylnucleosides. The affinity of the enzyme for each substrate was determined by kinetic analysis. It was found that the affinity increased markedly when one nucleotide was attached to the 3' end of the DNA strand of the nine-base-pair hybrid duplex and then increased slightly as the DNA strand was extended further, whereas elongation of the strand in the other direction caused no change. When a mutant enzyme, in which three lysine residues in the basic protrusion were altered to alanine, was used, no increase in the kcat/K(m) value was observed. The results indicate that, for the productive binding, the axis from the 3' to the 5' end of the RNA strand of the substrate duplex must be oriented in agreement with the direction from the active site to the basic protrusion of the enzyme. The distance between the active site and the basic protrusion in the enzyme-substrate complex was shorter than that anticipated in modeling studies. A dynamic structure refinement, referred to as the normal mode analysis, was carried out in order to simulate the fluctuations of the basic protrusion.
Escherichia coli↗
Recognition of 2'-hydroxyl groups by Escherichia coli ribonuclease HI.
In order to investigate the hydrogen-bonding interactions between Escherichia coli ribonuclease HI and the 2'-hydroxyl functions of the substrate, oligonucleotide duplexes containing 2'-amino-2'-deoxyuridine or 2'-fluoro-2'-deoxyuridine at a specific site were used, and their affinities for the enzyme were determined by kinetic analyses. The results indicate that the hydroxyl groups of the nucleoside 3'-adjacent to the cleaved phosphodiester linkage and the second nucleoside 5' to the cleaved phosphodiester act as both a proton donor and an acceptor and as a proton acceptor, respectively, in the enzyme-substrate complex. A molecular model was constructed using the interactions derived from the results.
Base Sequence↗
Plasma bradykinin levels during hemodialysis with PAN DX and polysulfone membranes with and without concurrent ACE inhibitor.
The effects of dialyzer membrane material and concurrent angiotensin converting enzyme (ACE) inhibitor on plasma bradykinin levels during hemodialysis were investigated by administration of 3 successive hemodialyses using a PAN DX membrane dialyzer and another 3 using a polysulfone membrane dialyzer with the order of the 2 sequences randomized, for 6 patients receiving concurrent treatment with ACE inhibitor and 6 others receiving no ACE inhibitor. With the PAN DX membrane dialyzer the plasma bradykinin concentration obtained from the dialyzer outlet was significantly higher than that from the inlet at 10 min, but not at 5 min after initiation of dialysis, whereas no significant difference between inlet and outlet bradykinin concentrations was observed at either time with the polysulfone membrane dialyzer. No significant difference was observed between the changes in plasma bradykinin concentration in cases involving concurrent ACE inhibitor and that in cases receiving no ACE inhibitor. The results suggest that the PAN DX membrane dialyzer stimulates bradykinin production, but also that its release of bradykinin is delayed, possibly because of adsorption and modified release of bradykinin by the PAN DX membrane, and that ACE inhibitor may have no significant effect on the change in plasma bradykinin levels.
Anaphylaxis↗
Nerve regeneration in predegenerated basal lamina graft: the effect of duration of predegeneration on axonal extension.
We used predegenerated acellular grafts to bridge proximal and distal stumps of transected nerves and studied how the duration of predegeneration might affect axonal regeneration. Predegenerated acellular grafts were prepared by transecting the tibial nerve of donor rats and, after a period of degeneration, freeze-thawing a 40-mm long segment of the distal stump. Five degeneration periods were used: 0 days (for fresh grafts), 3 days, 1 week, 4 weeks, and 8 weeks. Fresh cellular grafts not treated with freeze-thawing were also used for comparison. Each graft was then transplanted to an isogeneic recipient rat, in which it was used to bridge the proximal stump of the transected left tibial nerve and the distal stump of the transected right tibial nerve. Six weeks were allowed for the regeneration of axons in all grafts. The regeneration was then assessed by studying transverse sections of the grafts, to determine the maximum length that the axons had regenerated, and the packing density of axons (percentage of sampled areas occupied by axons). The results show that axons had grown to the maximum length in the 4-week predegenerated grafts, and had the highest packing density in the 1-week predegenerated grafts. Regeneration in the fresh acellular (0-day predegenerated) and 8-week predegenerated grafts, especially the latter, was poor. We examine the results with reference to time-dependent events of Wallerian degeneration and propose that there are beneficial effects of multiple factors on the grafts during the first 4 weeks of predegeneration, causing a slow but significant improvement in their capability to support axonal growth. The subsequent rapid deterioration of such capability may be related to structural changes in the extracellular scaffold.
Animals↗
Effect of dialysis membranes and ACE inhibitor on bradykinin levels during hemodialysis.
The effects of dialyzer membrane material and concurrent angiotensin converting enzyme (ACE) inhibitor on plasma bradykinin levels during hemodialysis were investigated. Six patients treated with an ACE inhibitor and 6 other patients not receiving an ACE inhibitor underwent three consecutive hemodialysis sessions with an AN-69 dialyzer and three sessions with a polysulfone dialyzer. The sequence of dialyzers (AN-69 followed by polysulfone or the reverse) was determined randomly. With the AN-69 membrane dialyzer, the plasma bradykinin level at the dialyzer outlet was significantly greater than that at the dialyzer inlet at 5 min but not at 10 min after initiation of dialysis, whereas no significant difference between inlet and outlet bradykinin concentrations was observed at either time with the polysulfone membrane dialyzer. The changes in plasma bradykinin level in patients with concurrent ACE inhibitor did not differ from those found in patients without ACE inhibitor. These results indicate that the AN-69 membrane stimulates bradykinin production at the initial stage of hemodialysis in patients with as well as without concurrent ACE inhibitor. Further study is necessary to clarify the exact role of ACE inhibitor in elevation of bradykinin levels during hemodialysis.
Anaphylaxis↗
Nafamostat as anti-coagulant for membrane plasmapheresis in high bleeding risk patients.
Nafamostat mesilate (NM), an ultrashort-acting multi-enzymatic inhibitor, is a useful anti-coagulant in high bleeding risk patients needing hemodialysis. We applied NM as a membrane plasmapheresis (MP) anti-coagulant in patients with high bleeding risk. Eleven patients, the majority with hepatic failure and active hemorrhagic foci or severe bleeding diathesis, could be treated with MP 22 times under anti-coagulation by 20-40 mg/h/NM by continuous infusion without any trouble. Celite-activated coagulation time (CCT) at the plasma separator inlet and outlet was adequately prolonged during MP, but CCT in systemic blood showed no prolongation throughout the procedure, because NM was rapidly inactivated. There was no observable blood coagulation in the extracorporeal circuit including the plasma separator. No adverse reaction or exacerbation of hemorrhage was noted throughout the MP. NM thus appears to be a useful and safe anti-coagulant not only for hemodialysis but also for MP in high bleeding risk patients.
Adolescent↗
Estimation of circulating immune complexes following oral challenge with cow's milk in patients with IgA nephropathy.
We recently reported on an experimentally induced model of IgA nephropathy in mice by long-term oral immunization under the reticuloendothelial dysfunction, which was found to be effectively inhibited by the administration of the antiallergic agent sodium cromoglycate (SCG). On the basis of these findings, we investigated the participation of food antigens in patients with IgA nephropathy. We studied 24 patients with IgA nephropathy, 11 patients with primary glomerulonephritis (PGN) except IgA nephropathy and 11 healthy controls. Serum levels of immunoglobulins (IgG, IgA, IgE) and circulating immune complexes containing IgG (IgG-CIC) or IgA (IgA-CIC) were measured in the fasting state and 30, 60, 120 or 180 min after oral challenging with cow's milk (400 ml). After the oral challenge IgA-CIC levels remained within the normal range in healthy controls and in patients with PGN, while 3 out of the 24 patients with IgA nephropathy showed a transient elevation and 2 cases showed a significant rise of IgA-CIC levels. The levels of IgG, IgA, IgE and IgG-CIC remained uninfluenced by the challenge test in all subjects. In addition, we carried out the same challenge test under SCG administration. These cases indicating an oral-challenge-induced IgA-CIC elevation demonstrated an inhibition of this elevation, and in 3 out 7 patients who showed hyper-IgA-CIC-emia before and after oral challenge IgA-CIC levels returned to the normal range through SCG administration. These results suggest that food antigens participate strongly in the pathogenesis of some patients with IgA nephropathy, and that SCG is an effective agent for such patients.
Animals↗
Yellow nail syndrome associated with chronic pericardial effusion.
A 74-year-old man had typical yellow nail syndrome, associated with pericardial effusion and hyperimmunoglobulinemia (IgG 3,179 mg/dl, IgM 402 mg/dl). A search of the literature fails to reveal a previously reported case of yellow nail syndrome associated with pericardial effusion.
Aged↗
[Respiratory failure secondary to mycoplasma pneumoniae infection].
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Acute Disease↗