Search for the H dibaryon in (K-,K+) reactions.
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Journal Article↗
Biomedical subjects
Y Maeda
Publications and source records attributed to Y Maeda.
Differential scanning calorimetric study of the effect of intercalators and other kinds of DNA-binding drugs on the stepwise melting of plasmid DNA.
The effect of intercalating drugs (the anthracycline group of antibiotics, ethidium bromide, actinomycin D) on stepwise melting of DNA was studied by differential scanning calorimetry (DSC). The DSC DNA melting profile of plasmid pJL3-TB5 DNA (5277 base-pairs in length) consists of seven peaks, and all the intercalators caused shifting of these peaks, particularly those formed at the high temperature ranges, to the higher temperature ranges in a characteristic manner depending upon the binding strength of the drug. The analysis of the anthracycline group of antibiotics, such as aclacinomycin A, daunomycin, adriamycin and pyrarubicin, indicates that the difference in binding is due to the sugar moiety at position O-7 of the chromophore in these antibiotics. Analysis on the basis of the helix-coil transition theory suggests that the anthracycline group of antibiotics interact preferentially with the 5'-CG-3' sequences. The effect of various DNA-binding drugs other than intercalators on stepwise melting of DNA was then studied by DSC. The representative drugs examined were distamycin A, peplomycin, cis-dichlorodiamine-platinum(II) (cis-DDP or cis-Platin) and mitomycin C, which differ in their mode of interaction with DNA; namely, minor groove binding, strand cleavage and intrastrand or interstrand cross-linking. Distamycin A caused shifting of the DSC peaks at the low temperature ranges to a higher temperature range, whereas peplomycin and cis-DDP caused shifting of all the DSC peaks to form a broad peak at a lower temperature range, suggesting that the DSC DNA melting profiles are affected in a characteristic manner depending upon the interaction mode of the drug.
Antibiotics, Antineoplastic↗
Detection of antibodies to human T-lymphotropic virus type I by using synthetic peptides.
We describe an enzyme-linked immunosorbent assay (ELISA) for antibodies to HTLV-I using synthetic peptides corresponding to antigenic regions of HTLV-I structural protein. We observed that the peptides amino acid 100-119, 100-130, 131-160 and 295-314 of the gag protein, and 89-115, 175-199, 350-386 and 458-488 on the env protein correspond to the antigenic regions of HTLV-I structural protein. In particular, the peptide corresponding to amino acid 100-130 of the gag protein reacted with antibodies in all sera from HTLV-I carriers diagnosed by particle agglutination assay (PA) and indirect immunofluorescence assay (IF), but did not react with sera from healthy volunteers judged to be negative by PA and IF. Our results indicate that the ELISA using the peptide 100-130 of the gag protein can be used for donor screening of HTLV-I antibodies.
Amino Acid Sequence↗
Enhancement of the thermostability of subtilisin E by introduction of a disulfide bond engineered on the basis of structural comparison with a thermophilic serine protease.
Sites for Cys substitutions to form a disulfide bond were chosen in subtilisin E from Bacillus subtilis, a cysteine-free bacterial serine protease, based on the structure of aqualysin I of Thermus aquaticus YT-1 (a thermophilic subtilisin-type protease containing two disulfide bonds). Cys residues were introduced at positions 61 (wild-type, Gly) and 98 (Ser) in subtilisin E by site-directed mutagenesis. The Cys-61/Cys-98 mutant subtilisin appeared to form a disulfide bond spontaneously in the expression system used and showed a catalytic efficiency equivalent to that of the wild-type enzyme for hydrolysis of a synthetic peptide substrate. The thermodynamic characteristics of these enzymes were examined in terms of enzyme autolysis (t1/2) and thermal stability (Tm). The half-life of the Cys-61/Cys-98 mutant was found to be 2-3 times longer than that of the wild-type enzyme. Similar results were obtained by differential scanning calorimetry. The disulfide mutant showed a Tm of 63.0 degrees C, which was 4.5 degrees C higher than that observed for the wild-type enzyme. Under reducing conditions, however, the characteristics of the mutant enzyme were found to revert to those of the wild-type enzyme. These results strongly suggest that the introduction of a disulfide bond by site-directed mutagenesis enhanced the thermostability of subtilisin E without changing the catalytic efficiency of the enzyme.
Amino Acid Sequence↗
Parathyroid hormone-related protein in tumor tissues obtained from patients with humoral hypercalcemia of malignancy.
We assessed the relationship between the parathyroid hormone-related protein (PTHrP) and the development of humoral hypercalcemia of malignancy (i.e., hypercalcemia due to the production by solid tumors of hypercalcemic factors) by assaying tumor extracts from hypercalcemic and normocalcemic patients with cancer for immunoreactive PTHrP contents. Immunoreactive PTHrP was demonstrated in extracts of 21 of 22 tumor tissues obtained from 22 patients with humoral hypercalcemia of malignancy. Immunoreactive PTHrP was rarely seen in tumor tissue extracts obtained from 34 normocalcemic patients with cancer and two hypercalcemic patients with cancer with severe bone metastases. Gel filtration studies of tumor extracts revealed a molecular-size heterogeneity of immunoreactive PTHrP. These radioimmunoassay data indicate a close relationship between detection of PTHrP in tumor tissues and the development of humoral hypercalcemia of malignancy.
Adult↗
Treatment of platelet-alloimmunization with cyclosporin A in a patient with aplastic anemia.
The development of alloantibodies to platelets is a major problem in the supportive management of thrombocytopenia in patients with severe aplastic anemia. We report here a case of aplastic anemia refractory to platelet transfusion. An immunosuppressant, cyclosporin A, which was used for the therapy of aplastic anemia, modulated alloimmunization to platelets in this patient, followed by repeated platelet transfusion. The treatment reduced platelet alloantibodies detected by anti-human immunoglobulin lymphocytotoxicity test, with change of the CD4/CD8 ratio in T lymphocytes in peripheral blood. These results suggest the usefulness of cyclosporin A for the prevention of platelet alloimmunization.
Adult↗
Autoimmune mechanisms in peripheral neuropathies.
In certain patients with demyelinating neuropathy and plasma cell dyscrasia, there are IgM monoclonal antibodies that recognize a carbohydrate epitope shared by myelin-associated glycoprotein (MAG) and at least two acidic glycolipids in the peripheral nervous system (PNS). The structures of the two acidic lipids have been elucidated as a new class of glycosphingolipids, termed sulfoglucuronyl glycolipids (SGGLs). SGGLs have been demonstrated to be present in myelin, axolemma, and other glia-related membranes in PNS of several animal species, as well as in human dorsal root ganglia and sympathetic ganglia. In rabbits sensitized with sulfoglucuronyl paragloboside (SGPG), a major SGGL in PNS, antibodies developed with reactivities toward SGPG and MAG. The animals also showed moderate weakness, a slowed nerve conduction velocity, and evidence of conduction block. Recently we also found SGPG in rat brain microvessels. This finding supports our hypothesis that autoantibodies may first interact with endothelial cell-bound antigens and that this might change the permeability of the blood-brain or blood-nerve barrier to permit the entry of these autoantibodies into the nervous system. Our data are consistent with the concept that an autoimmune response against the sulfoglucuronyl residue may participate in the pathogenesis of immune-mediated neuropathy.
Animals↗
Trajectory formation of arm movement by cascade neural network model based on minimum torque-change criterion.
We proposed that the trajectory followed by human subject arms tended to minimize the time integral of the square of the rate of change of torque (Uno et al. 1987). This minimum torque-change model predicted and reproduced human multi-joint movement data quite well (Uno et al. 1989). Here, we propose a neural network model for trajectory formation based on the minimum torque-change criterion. Basic ideas of information representation and algorithm are (i) spatial representation of time, (ii) learning of forward dynamics and kinetics model and (iii) relaxation computation based on the acquired model. The model can resolve ill-posed inverse kinematics and inverse dynamics problems for redundant controlled object as well as ill-posed trajectory formation problems. By computer simulation, we show that the model can produce a multi-joint arm trajectory while avoiding obstacles or passing through viapoints.
Algorithms↗
Effects of hyperglycaemia on sorbitol and myo-inositol contents of cultured embryos: treatment with aldose reductase inhibitor and myo-inositol supplementation.
To demonstrate the myo-inositol depletion hypothesis in hyperglycaemia-induced embryopathy, rat conceptuses of 9.5 days of gestation in the early head-fold stage were grown in vitro during neural tube formation for 48 h with increasing amounts of glucose. The effects of an aldose reductase inhibitor and the myo-inositol supplementation were also investigated. Sorbitol and myo-inositol contents were measured in separated embryos and extra-embryonic membranes including yolk sac and amnion at the end of culture. After addition of 33.3 mmol/l and 66.7 mmol/l glucose to the culture media, the myo-inositol content of the embryos was significantly decreased by 43.1% (p less than 0.05) and 64.6% (p less than 0.01) of the control group, while a marked accumulation of sorbitol was observed (25 and 41 times that of the control). Although the addition of an aldose reductase inhibitor (0.7 mmol/l) to the hyperglycaemic culture media containing an additional 66.7 mmol/l glucose significantly reduced the sorbitol content of embryos to approximately one-eighth, the myo-inositol content of embryos remained decreased and the frequency of neural lesions was unchanged (23.1% vs 23.9%, NS). Supplementation of the myo-inositol (0.28 mmol/l) completely restored the myo-inositol content of the embryos and resulted in a significant decrease in the frequency of neural lesions (7.1% vs 23.9%, p less than 0.01) and a significant increase in crown-rump length and somite numbers. Much less significantly, sorbitol accumulation was also observed in the extra-embryonic membrane in response to hyperglycaemia, neither hyperglycaemia nor the myo-inositol supplementation modified the myo-inositol contents of the extra-embryonic membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
Aldehyde Reductase↗
Structural difference of chymotrypsinogens forming chymotrypsin variants in Japanese quail.
A chymotrypsinogen showing the phenotype AA of chymotrypsin was purified from quail pancreas, and its chromatographic behavior, molecular weight, and electrophoretic mobility were very similar to those of another chymotrypsinogen, showing the aa phenotype of chymotrypsin. However, after activation, this chymotrypsinogen from AA showed band 5 of chymotrypsin, while the other chymotrypsinogen from aa did not. Peptide mapping demonstrated that the molecular structures of the two chymotrypsinogens are different. It was recognized that chymotrypsin variants result from activated products of different molecular structures of chymotrypsinogens.
Animals↗
Mechanical characteristics of skinned and intact muscle fibres from the giant barnacle, Balanus nubilus.
Intact muscle fibres from Balanus nubilus develop tensions of up to 600 kN.m-2 during electrical stimulation. The rise of tension occurs with a half-time (177 ms at 12 degrees C) about fivefold longer than that of tetanised frog muscle at the same temperature. The response of myofibrillar bundles to a rapid stretch resembles that of frog muscle but has a yo value (i.e. the size of an instantaneous release necessary to just discharge tension) which is ca. 2.5 times smaller, and phase 2 of the tension transient (the "quick phase") occurs at a rate comparable to that of frog muscle. In contrast, the ATPase activity (0.018 mmoles.kg wet weight-1.s-1) of this preparation and its maximum shortening velocity (0.15-0.16 muscle lengths.s-1) are both at least fivefold slower than frog muscle. These findings can be accounted for by a cross-bridge cycle in barnacle muscle in which events prior and subsequent to the tension generating step(s) occur at a rate at least fivefold slower than comparable steps in frog muscle, but the step(s) associated with tension development occur at similar rates in the two preparations. Since the rate of mechanical relaxation in barnacle muscle is modified in the presence of intracellular calcium buffers and by depolarisation-induced elevation of the free calcium during the relaxation phase, it is proposed that the time course of relaxation is not determined exclusively by the kinetics of the cross-bridge cycle, but is also dependent on the free calcium concentration during relaxation.
Adenosine Triphosphatases↗
The effects of histamine on the concentrations of immunoreactive thyrotropin-releasing hormone in the stomach and hypothalamus in rats.
The effects of histamine and its related compounds on the concentrations of immunoreactive thyrotropin-releasing hormone (ir-TRH) in the stomach, gastric juice and hypothalamus in rats were studied. Histamine, ranitidine or ethanolamine was injected intraperitoneally, and the rats were decapitated at various times after the injection. Ir-TRH concentrations in the stomach, gastric juice and hypothalamus were measured by a radioimmunoassay. Ir-TRH concentrations in the stomach decreased significantly after histamine injection and increased significantly after ranitidine injection in a dose-dependent manner, but did not change with ethanolamine. Ir-TRH concentrations in the gastric juice increased in a dose-dependent manner, peaking at 30 min after histamine injection, and its effect was blocked with ranitidine. Ir-TRH concentrations in the hypothalamus elevated significantly after histamine injection and reduced significantly after ranitidine injection, but did not change with ethanolamine. The effects of histamine on ir-TRH concentrations in the stomach and hypothalamus were significantly blocked with ranitidine, but not with ethanolamine. These findings suggest that histamine stimulates ir-TRH release from the stomach and inhibits ir-TRH release from the hypothalamus, and that these effects of histamine on ir-TRH release are mediated via an H2-receptor.
Animals↗
Purification and characterization of chymotrypsinogen from pancreas of Japanese quail (Coturnix coturnix japonica).
1. A chymotrypsinogen from pancreas of Japanese quail (Coturnix coturnix japonica) was purified by acid extraction, salt fractionation and chromatographic separation on CM-cellulose and Sephadex G-100, and gave a single protein band on SDS-PAGE. 2. Quail chymotrypsinogen had a mol. wt of 26,100 calculated from amino acid composition data, an isoelectric point of 7.68, a Km of 3.1 mM and K0 of 40.7 sec-1 for tyrosine ester substrate. 3. The activated chymotrypsinogen of quail had a maximum activity at pH 7.0-8.0 and at 45 degrees C, and was stable at pH 4.0-6.0 below 55 degrees C. 4. Comparison of quail and bovine chymotrypsinogens indicates that the activities of the enzymes from quail and bovine are more constant than their physical characteristics.
Amino Acids↗
Human Fc epsilon RII and IgE-binding factor; triangular network with IL-2 and IL-4.
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Antigens, Differentiation, B-Lymphocyte↗
Selective killing of HIV-infected cells by anti-gp120 immunotoxins.
Either ricin A chain (RAC) or Pseudomonas exotoxin (PE) was conjugated with a murine monoclonal antibody (0.5 beta) directed against an external envelope glycoprotein (gp120) of human immunodeficiency virus (HIV). Effects of the immunotoxins produced against infected cells were evaluated. Selective inhibition of the proliferation and killing of chronically HIV infected cells were observed in the presence of the immunotoxins. To determine the feasibility of the immunotoxins against the infected cells in seropositive subjects, we attempted to detect gp120-bearing cells in peripheral blood mononuclear cells (PBM) by cytofluorography. Cells in the monocyte/macrophage region of 2 of 10 PBM samples from HIV-infected individuals were found to react with 0.5 beta (18.1% and 12.8%). Furthermore, the cell population which was reactive with 0.5 beta was also susceptible to RAC conjugated with 0.5 beta. These results suggest that the strategy of using anti-gp120 immunotoxin to eliminate HIV-infected cells may be feasible in infected individuals.
Amino Acid Sequence↗
Electroclinical study of video-game epilepsy.
Seven patients (five boys, two girls) with video-game epilepsy (VGE) are reported, which reflects the fact that these games have increased in popularity recently among Japanese children. Their ages at onset ranged from four to 13 years. The seizure phenomena were of three types: generalised tonic-clonic, partial seizure and headache. Interictal physical and neurological examinations were within normal limits. EEGs taken while they played video-games confirmed the diagnosis of VGE and revealed three triggers of seizures: flashing lights, special figure patterns and scene-changing. They were recommended to avoid playing video-games, but sodium valproate was effective if seizures persisted even after such avoidance.
Adolescent↗
Sulfated glucuronyl paragloboside in rat brain microvessels.
In patients with neuropathy associated with paraproteinemia, there are monoclonal immunoglobulin M antibodies reacting with myelin-associated glycoprotein and sulfated glucuronyl glycolipids. There are indications that the monoclonal antibodies may be responsible for these neuropathies. However, the mechanism by which the antibodies gain access to the nervous tissue, which is separated by the blood-brain barrier or blood-nerve barrier, is still unknown. In this study, we examined the presence of the sulfated glucuronyl glycolipid antigens on brain endothelial cells. Microvessels were isolated from adult Lewis rat brain cortex. Sulfated glucuronyl paragloboside (SGPG) was detected in the acidic lipid fraction by a TLC immunostaining method. Immunofluorescence studies showed positive staining on the surface of microvessels. In addition, SGPG could be detected in the cultured endothelial cells of human umbilical vein. These findings suggest that the endothelial cells contain antigenic sites for interaction with the autoantibodies. This type of interaction may result in damages to the endothelial cell function and may be responsible for changes in the blood-brain barrier permeability and the ensuing penetration of large molecules, such as immunoglobulins, into the endoneurial space.
Animals↗
Immunohistochemical study of jaw cysts: different existence of keratins in odontogenic and non-odontogenic epithelial linings.
Keratins and secretory component (SC) were immunohistochemically examined in fresh tissue samples from 45 odontogenic and 35 non-odontogenic cysts. Lining epithelia of almost all cases contained keratins which reacted with polyclonal antibodies (Dako, Bio-Science), and no difference could be found between the two groups of lesions. By staining with two monoclonal antibodies against keratins, i.e., RGE53 (Bio-Science) and RKSE60 (Bio-Science), it was revealed that the epithelia of non-odontogenic cysts, which were columnar epithelium in most cases, had fully and positively reacted with RGE53, while none of the cases was positive for RKSE60. In contrast, the squamous linings of odontogenic cysts except for two cases did not react with RGE53, and few cases possessed RKSE60-reactive keratin. SC was also contradictory. All non-odontogenic cysts exhibited SC. Regarding each pair of non-odontogenic and odontogenic cysts covered with RGE53 and SC-positive, and RKSE60-negative squamous epithelium, it seemed reasonable from the staining results to conclude that the squamous linings were metaplastic from the columnar epithelium. Based on the results, concomitant examinations of SC with keratins will be helpful in deciding the epithelial derivation of jaw cysts.
Dentigerous Cyst↗