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Biomedical subjects

Y Inada

Publications and source records attributed to Y Inada.

At least 235 records · Page 13Linked to original sources
PubMed1986

Fucosterol decreases angiotensin converting enzyme levels with reduction of glucocorticoid receptors in endothelial cells.

The modulation of angiotensin converting enzyme (ACE) levels was studied using fucosterol, one of phytosterols, in cultured bovine carotid endothelial cells. Addition of fucosterol to the culture medium resulted in the decrease of ACE activity of endothelial cells; however, fucosterol did not directly inhibit ACE activity. Dexamethasone elevated the levels of ACE in normal cells, but this effect was not seen in the fucosterol-treated cells. Receptor assays showed that the amount of glucocorticoid receptors in fucosterol-treated cells decreased to an undetectable level. These results indicate that fucosterol lowers the ACE levels on the endothelial cells by inhibiting the synthesis of glucocorticoid receptors involved in the regulation of ACE levels.

Cells, Cultured↗
PubMed1986

Polyethylene glycol-modified hemin having peroxidase activity in organic solvents.

Hemin, having two carboxyl groups, was coupled with monomethoxypolyethylene glycol, PEG, through the ester bond formed with carbodiimide. The PEG-modified hemin was readily soluble not only in neutral aqueous solution but also in organic solvents. Its absorption spectrum in 1,1,1-trichloroethane showed a sharp Soret band at 398 nm. The modified hemin catalyzed the peroxidase-reaction in organic solvent and in aqueous solution using hydrogen peroxide or peroxidized linolenic acid as hydrogen acceptor and o-phenylene diamine as hydrogen donor. The activity of PEG-hemin in 1,1,1-trichloroethane was greater than that in an aqueous solution; k1 values in 1,1,1-trichloroethane were 2.3 X 10(3) M-1 sec-1 with hydrogen peroxide and 7.0 X 10(2) M-1 sec-1 with peroxidized linolenic acid, and the value in an aqueous solution was 3.0 X 10 M-1 sec-1 with hydrogen peroxide.

Heme↗
PubMed1986

Interaction between plasma factor XIII and collagen.

Purified plasma Factor XIII efficiently bound to the immobilized collagen affinity column. In contrast, when plasma was applied to the column, as much as 80% of Factor XIII was not trapped. It was shown that the difficulty of binding of Factor XIII in plasma to collagen is not due to the covering of collagen with some plasma proteins. We then assumed that Factor XIII formed a complex in plasma with a certain protein(s), which would prevent Factor XIII from binding to collagen. Using an immobilized Factor XIII affinity column, we have indeed obtained one protein from plasma with apparent Mr of 260,000.

Animals↗
PubMed1986

Platelet factor XIII. The collagen receptor?

We have studied the binding of collagen fibers with platelet proteins using affinity chromatography on collagen-Sepharose. Only a few proteins from a platelet lysate were trapped by this column. When denatured collagen (gelatin) was used as the affinity ligand, the major protein did not bind and was identified as platelet Factor XIII by polyacrylamide gel electrophoresis, immunoprecipitation, and enzymic activity. This is a zymogen form of transglutaminase, which corresponds to the "a" subunit of the coagulation factor in plasma. Immunoglobulins specific for platelet Factor XIII obtained from antiserum raised against plasma Factor XIII were able to initiate platelet aggregation by themselves, in strong contrast to nonspecific antibodies. This specific immunoglobulin-mediated platelet aggregation required the presence of Ca2+. It was inhibited by aspirin and prostacyclin, but not by specific inhibitors for other agonists. These data suggest the possibility that the zymogen form of Factor XIII is located on the surface of platelets and may play a key role as the receptor for collagen-induced platelet aggregation.

Animals↗
PubMed1986

Specific desensitization in the cytoskeletal assembly of platelet by receptor-dependent activations.

Cytoskeletal assembly induced by receptor-dependent or independent activation of bovine platelets was investigated. When platelets were preactivated with receptor-dependent stimulus, ADP or thrombin, cytoskeletal assembly was not induced repeatedly by the same agonist. However, in the case of receptor-independent stimulus, cryo-activation, the assembly was induced not only by receptor-dependent but also by independent stimulus. The desensitization, therefore, lies in the transmission of stimuli from receptors to cytoskeletal proteins.

Actins↗
PubMed1986

Visible fibrinolysis by endothelial cells: effect of vitamins and sterols.

We have succeeded in corroborating the enhancing effect of vitamin A, vitamin C, sitosterol and fucosterol on the fibrinolytic activity of endothelial cells. The assay system consisted of an in situ dissolution of a fibrin layer coated onto a culture dish, over which endothelial cells were grown in a culture medium containing 10% serum. The dissolution was enhanced by the addition of these vitamins and phytosterols to the culture medium.

Animals↗
PubMed1986

Modification of transglutaminase assay: use of ammonium sulfate to stop the reaction.

An important modification was made of the assay for transglutaminase regarding dansyl cadaverine incorporation into casein. It is known that the amine, after incorporation into protein by transglutaminase, shows a marked increase of fluorescence accompanied by a slight blue shift. However, measurement of protein-bound fluorescence requires a rather complicated procedure, such as the precipitation by trichloroacetic acid or continually monitoring the fluorescence. To widen the applicability of the method, we utilized an excess concentration of ammonium sulfate to stop the reaction. At concentrations higher than 5 mM, the incorporation of the amine was completely stopped and the fluorescence was retained for more than 2 h. The fluorescence can be measured directly after stopping the reaction, so it has become feasible to assay many samples at a time. Furthermore, the sensitivity and reproducibility of the data were improved, since the reaction time could be prolonged and strictly defined.

Ammonium Sulfate↗
PubMed1986

Distinctive role of histidine-16 of the B beta chain of fibrinogen in the end-to-end association of fibrin.

Photooxidation of fibrinogen reduced the batroxobin-induced fibrin polymerization. The fibrin fragment des-AB N-DSK, which contains the binding sites termed A and B, lost the ability to bind to the site termed a in fibrinogen-Sepharose upon the oxidation of histidine-16 in the B beta chain of fibrinogen [Shimizu, A., Saito, Y., Matsushima, A. & Inada, Y. (1983) J. Biol. Chem. 258, 7915-7917]. Some of the fragments, which became unable to bind to fibrinogen-Sepharose due to the destruction of site A, however, retained the ability to bind to D-dimer-Sepharose, which contains both sites a and b. This shows that histidine-16 of the B beta chain of fibrinogen is essential for site A but may not be essential for site B. It is of interest that histidine-16 of the B beta chain, which is only one residue away from the thrombin-susceptible bond, makes a part of the site A for the end-to-end association created by the release of fibrinopeptide A.

Binding Sites↗
PubMed1986

Hematologic correlates and the role of erythrocyte CR1 (C3b receptor) in the development of AIDS.

Circulating immune complexes (CICs) are common in patients with the acquired immunodeficiency syndrome (AIDS) as in anemia. In our previous reports, we observed that the deposition of CICs on erythrocytes via C3b receptors (CR1) resulted in a defective CIC clearing system of erythrocytes and in high membrane osmotic fragility of such erythrocytes. We investigated the functional activity of erythrocyte CR1 in 89 patients with AIDS, 41 with AIDS related complex (ARC), 102 healthy homosexual volunteers, and 37 heterosexual males, in relation to the presence of CICs, antibody to lymphadenopathy associated virus/human T lymphotropic virus-III (LAV/HTLV-III), anemia, and the direct and indirect Coombs' tests. CICs were frequently found in all groups except heterosexual males. Absence of CR1 activity was observed in 85% of patients with AIDS, and in 59% with ARC. Impaired CR1 activity also occurred in the homosexual volunteer group. Positive direct Coombs' test and the presence of CICs correlated inversely with CR1 activity while a lowered hematocrit and the presence of antibody to LAV/HTLV-III correlated directly. Neither the sera nor the eluates from erythrocytes with a positive IgG Coombs' test contained IgG antibody against erythrocytes. This suggests decremental loss of CR1 activity progressing from asymptomatic LAV/HTLV-III antibody positive homosexual volunteers to the prodromal spectrum of ARC and finally progressing to a total disappearance in overt AIDS. Of 8 homosexuals volunteers demonstrating the composite of impaired CR1 activity, positive antibody to LAV/HTLV-III, and polyvalent positive direct Coombs' test (with gamma, mu, and C3b), all developed ARC or overt AIDS within 2 years of these observations.

AIDS-Related Complex↗
PubMed1986

Increased N-pentane excretion in humans: a consequence of pulmonary oxygen exposure.

Lipid peroxidation by free radicals has been suggested as a mechanism of a lung injury caused by breathing higher than normal concentrations of oxygen. The appearance of hydrocarbons such as n-pentane in the expired gas of mammals has been proposed as in vivo evidence of lipid peroxidation. The excretion of n-pentane was studied in 15 healthy volunteers in whom excretion of exogenous n-pentane was determined over a 60- to 90-min period while breathing hydrocarbon-free gases. N-pentane elimination rates (mean +/- SEM) in the expired gas at 0, 30, 60, 90, and 120 min were 10.2 +/- 1.5, 1.6 +/- 0.2, 1.2 +/- 0.9, 1.3 +/- 0.4, and 1.3 +/- 0.3 (pmol X kg-1 X min-1), respectively. Using a specially assembled circuit, a 2-h oxygen exposure study was performed on six healthy volunteers, in whom basal n-pentane excretion varied ten-fold among individuals, from 0.25 to 2.25 pmol X kg-1 X min-1. After breathing 100% oxygen, n-pentane excretion was augmented 62-420% within 30 to 120 min. The authors conclude that lipid peroxidation may occur in humans within 30 min of breathing 100% oxygen.

Adult↗
PubMed1986

Effect of coenzyme Q10 on endotoxin shock in dogs.

We studied the effects of coenzyme Q10 pretreatment on both pulmonary function and chemical mediators during endotoxin shock in dogs. Coenzyme Q10 pretreatment inhibited disturbances in peak airway pressure, total compliance of lung plus chest wall, lung clearance index, plasma histamine, base excess, and lactate; however, it had little effect on the circulation. The mechanism of coenzyme Q10's significant effects on pulmonary function during endotoxin shock is presently unknown.

Animals↗
PubMed1986

Relationships between C3b receptor (CR1) activity of erythrocytes and positive Coombs' tests.

Although positive direct Coombs' tests occur in most patients with active systemic lupus erythematosus (SLE), haemolytic anaemic associated with antibody to erythrocytes (E) occurs in less than 10%. Our studies show an association between positive direct Coombs' tests and both the presence of circulating immune complexes and diminished activity of the C3b receptor (CR1) of E. Data presented in this report suggest that in vivo binding of immune complexes and complement by the CR1 of E results in positive direct Coombs' tests in the absence of antibody to E. These observations explain the low frequency of haemolytic anaemia compared with the high frequency of direct positive Coombs' tests in patients with SLE.

Antibodies↗
PubMed1986

Chemical modification of tryptophanase from E. coli with polyethylene glycol to reduce its immunoreactivity towards anti-tryptophanase antibodies.

Escherichia coli tryptophanase was modified with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine (activated PEG2, MW 5,000 x 2). The modified tryptophanase, in which approximately 43% of the total 120 amino groups and 38% of the total 16 sulfhydryl groups in the molecule were coupled, completely lost the immunoreactivity towards anti-tryptophanase serum from rabbit. Approximately 10% of the enzymic activity was retained. The modified enzyme showed the same physicochemical properties as the native enzyme: Km value for L-tryptophan (0.3 mmol/l), optimum pH (8.0) and optimum temperature (50 degrees C). The modified enzyme was more resistant than the native counterpart against proteolytic digestion with trypsin.

Animals↗