Biomedical subjects

H Maeda

Publications and source records attributed to H Maeda.

At least 883 records · Page 49Linked to original sources

PubMed1989

Cytotoxicity of bacterial proteases in various tumor cells mediated through alpha 2-macroglobulin receptor.

The binding and cytotoxicity of a complex of fluorescein isothiocyanate-labeled 56K protease and alpha 2-macroglobulin (alpha 2M) were determined by using various human and rodent tumor cell lines. The binding was higher at 37 degrees C than at 4 degrees C; a rapid and progressive uptake that was time dependent was noted at 37 degrees C, whereas no uptake was observed at 4 degrees C, which indicated temperature-dependent internalization. The binding was highest in the fibroblastic and adenocarcinoma cells, and lowest in squamous and epidermoid cells. The Scatchard plots for the binding isotherms were linear, with an apparent Kassoc 1.17 to 2.99 x 10(-8) M for those cells with high alpha 2M receptor. The number of binding sites (alpha 2M receptor) per cell was 1.3 to 4.75 x 10(6). Values for squamous/epidermoid cells were much lower or undetectable. Fluorescent antibody staining indicated that MCF-7 and other cells with alpha 2M receptor internalized the protease-alpha 2M complex, whereas B-16 melanoma, which has little alpha 2M receptor on the cell surface, did not. Furthermore, when the cytotoxicity of this complex was compared with that of different cell lines, the cells with high rates of uptake of the complex required only a low concentration of the protease and vice versa. These results suggest a possible mechanism of cytotoxic action of protease: alpha 2M receptor-mediated endocytosis of the complex followed by destruction of cellular integrity after regeneration of proteolytic activity. Thus, cells with more alpha 2M receptor require only a low dose for cytotoxic action when compared with cells with little alpha 2M receptor.

Adenocarcinoma↗

PubMed1989

[Measurement of effective hepatic blood flow using 99mTc-PMT SPECT and single blood sampling].

Effective hepatic blood flow (EHBF) was measured from an uptake constant using single blood sampling and 99mTc-PMT hepatobiliary SPECT data. After intravenous injection of 3 mCi (111 MBq) of 99mTc-PMT, serial 1 min SPECT data were obtained for 7 minutes. A time activity curve (TAC) over the heart, that was normalized with the 5 minutes venous sample concentration (%/dose/ml), was used as a blood clearance curve (B(t]. And a TAC of the whole liver, that was normalized with the injected dose of 99mTc-PMT (%/dose), was used as a hepatogram (L(t]. An uptake constant representing EHBF, was estimated from the Rutland's method L. (t)/B(t) was plotted against integral of otB(t)dt/B(t), and the slope of the least square fitted straight line was determined as the uptake constant. In 16 cases, significant correlation was obtained between the 99mTc-PMT hepatic uptake at 5 minutes and the EHBF estimated from the blood clearance (r = 0.85, p less than 0.001). While there was a much better correlation between the EHBF from uptake constant and the EHBF from blood clearance (r = 0.95, p less than 0.001). In conclusion, this analysis for uptake constant of 99mTc-PMT SPECT data enables us to estimate EHBF with single venous sampling and in relatively short acquisition time. This method is thought to be very valuable in clinical practice.

Humans↗

PubMed1989

Association of complement alleles C4AQ0 and C4B5 with rheumatoid arthritis in Japanese patients.

We investigated polymorphisms of complement components C2, C4, and factor B (BF) in Japanese patients with rheumatoid arthritis (RA). The frequencies of C4AQ0 (32.1%) and C4B5 (35.9%) among RA patients were significantly higher than among healthy control subjects. C4B5 was strongly associated with HLA-Bw54, Bw59, DR4.1, and DQw4. C4AQ0 showed no association with HLA-Bw54 or Bw59, but there was weak association with HLA-DR4.1 and DQw4. The number of persons with both C4AQ0 and C4B5 was significantly higher in the RA patient group (relative risk 13.5). C2C and BFS were the most common alleles in RA patients, as well as in healthy control subjects. These data support the existence of 2 different putative susceptibility haplotypes (HLA-Bw54 or Bw59;C2C; BFS;C4A3;C4B5;DR4.1;DQw4 and C2C;BFS; C4AQ0;C4B1 or C4B2) in Japanese patients with RA.

Alleles↗

PubMed1989

Control of pharmaceutical properties of soybean trypsin inhibitor by conjugation with dextran. I: Synthesis and characterization.

The Kunitz-type soybean trypsin inhibitor (STI), a model protein, was conjugated with dextran (Mw, approximately 9900; STI-D), and its physicochemical and biochemical properties were studied to develop a novel delivery system for a protein drug. Conjugation was carried out using periodate oxidation, and cyanogen bromide, carbodiimide, cyanuric chloride, epichlorhydrin, and N-succiniimidyl-3-(2-pyridyldithio)propionate (SPDP) reagent methods. Dextran was conjugated to STI at a molar ratio of 1.5 to 4.6, but the degree of modification, as well as yield and contamination extent of unreacted STI and dextran, varied with the method of synthesis. Gel filtration and electrophoresis confirmed the covalent attachment of dextran to STI but also demonstrated the broad molecular weight distribution of the conjugates. The STI-D conjugate retained satisfactory activity, although the attachment partially reduced its inhibitory activity against trypsin. The periodate oxidation method seemed to be the best for the preparation of STI-D since it gave the conjugate with a high modification ratio (4.6 molecules per STI), high yield (95%), and satisfactory activity recovery (63%). Chemical modification of STI was also carried out with activated polyethylene glycol (PEG) for comparison. The STI-PEG conjugate was obtained in a satisfactory yield (96%) and modification degree (5.8 molecules per STI), but the remaining activity was considerably lower (34%). Thus, conjugation of protein with dextran by the periodate oxidation method is suggested to be preferable for preparing a protein-carrier system without significant diminution of its biological activity.

Carbodiimides↗

PubMed1989

Control of pharmaceutical properties of soybean trypsin inhibitor by conjugation with dextran. II: Biopharmaceutical and pharmacological properties.

Biopharmaceutical and pharmacological properties of the Kunitz-type soybean trypsin inhibitor (STI)-dextran conjugate (STI-D) were studied. Dextran having a molecular weight of approximately 10,000 was covalently attached to the STI molecule by periodate oxidation. The STI-polyethylene glycol (PEG) conjugate (STI-PEG) was also tested for comparison. After iv injection to mice, native STI showed rapid elimination of activity from plasma (t 1/2 = 2 min), and approximately 60% of the dose was excreted in urine within 1 h after injection. On the other hand, STI-D was slowly cleared from plasma and its urinary excretion was restricted. The STI-PEG conjugate showed a pharmacokinetic behavior similar to that of STI-D. Pharmacological activities of native and modified STI were evaluated by two animal experimental models; that is, trypsin-induced shock in mice and acute pancreatitis in rats. In mice, shock induced by iv injection of trypsin was inhibited by the iv pretreatment with native STI, but the effect was observed for only 1 h. The STI-D conjugate showed a superior inhibitory effect on trypsin-induced shock to that of STI alone at the same dose, and this effect continued for 5 h. A similar effect was also observed in mice given an iv injection of STI-PEG. In rats with acute pancreatitis, no significant therapeutic effect was shown by the iv treatment with native STI, as well as saline treatment. On the other hand, the iv treatment with STI-D at the same dose as STI lowered the mortality of the rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Quantification, isolation and structural determination of bradykinin and hydroxyprolyl-bradykinin in tumor ascites.

The presence of kinins in ascitic tumor fluids from rodents and human patients was identified and quantified. In bioassay, kinin content was found to be 1 to 40 ng/ml, and by enzyme immunoassay, 0.6 to 2.5 ng/ml. In particular, a high kinin content, 40 ng/ml, was found in the ascites of a gastric cancer patient by bioassay. Purification of this kinin in the ascites from the gastric cancer patient was performed by ethanol precipitation, gel filtration and reversed-phase high-performance liquid chromatography (HPLC). Two peaks (peak A and peak B) showed kinin activity. Peak A did not correspond to either bradykinin or other known kinins, such as lysyl-bradykinin and T-kinin, whereas peak B corresponded to bradykinin. Peak A contained 8 amino acid residues from bradykinin minus one proline plus an additional hydroxyproline. Sequence analysis of peak A showed that the proline at the third amino acid residue of bradykinin was replaced by hydroxyproline. The retention time of peak A on reversed-phase HPLC was exactly the same as that of synthetic hydroxyprolyl3-bradykinin (Hyp3-bradykinin) but was distinguishable from des-Pro3-bradykinin. Thus, these results demonstrate for the first time the presence of Hyp3-bradykinin in mammalian system.

Amino Acid Sequence↗

PubMed1989

Induction of an endogenous tumor necrosis factor in mice by murine recombinant interferon-gamma combined with a lipid A subunit analog (GLA-60) of low toxicity.

We have investigated the endogenous production of a serum cytotoxic factor when recombinant interferon-gamma (rIFN-gamma) is combined with synthetic lipid A subunit analogs of low toxicity (GLA compounds). The cytotoxic activity of the serum was measured by the crystal violet staining method with L929 cells as a target. Intravenous administration of rIFN-gamma followed by intravenous administration of lipopolysaccharide induced the endogenous production of a cytotoxic factor in the serum. The priming effect of rIFN-gamma appeared immediately and persisted for approximately 20 h after the injection. Administration of lipopolysaccharide as a trigger enhanced the production of the cytotoxic factor in the serum maximally 2 h after the injection. The cytotoxic activity in the serum was completely inhibited by anti-(mouse tumor necrosis factor) (TNF) antibody. A synthetic lipid A subunit analog (GLA-60), which is much less toxic in its endotoxin activities than lipopolysaccharide or synthetic lipid A (compound 506), induced the endogenous production of serum TNF in rIFN-gamma-primed mice. GLA-60 entrapped within liposomes induced the production of serum TNF in rIFN-gamma-primed mice more effectively than GLA-60 solubilized in phosphate-buffered saline. Intravenous or intranasal administrations of rIFN-gamma followed by intranasal administration of GLA-60 produced TNF in the lung washing fluid but not in the serum, indicating that TNF production can be induced locally rather than systemically by the alteration of the administration route of the primer and trigger. These results indicate that GLA-60, a lipid A subunit analog of low toxicity, is a beneficial triggering agent in the production of endogenous TNF, as well as having other immunopharmacological properties, and may provide a basis for cancer (metastases) treatment as a result of its ability to induce endogenous TNF.

Animals↗

PubMed1989

Stimulation of non-specific resistance to tumors in the mouse using a poly(maleic-acid-styrene)-conjugated neocarzinostatin.

The development of non-specific resistance to tumors following stimulation with poly(maleic-acid-styrene)-conjugated neocarzinostatin (SMANCS), a polymer-conjugated derivative of neocarzinostatin, was investigated in mice. The growth of syngeneic solid tumors (Meth-A fibrosarcoma and RL male 1 leukemia) inoculated into BALB/c mice was suppressed after one treatment with SMANCS at doses ranging from 0.14 mg/kg to 3.4 mg/kg i.v. 24 h before tumor implantation. Since previously observations concerning SMANCS have shown that it disappeared within 1.5 h after i.v. administration in mice and that it was inactivated quickly in plasma, SMANCS evidently inhibited tumor growth by mediating non-specific resistance. In addition, the non-specific resistance to tumors stimulated by SMANCS could be passively transferred to untreated mice by serum which was shown to contain interferon (IFN) from 12 h to 20 h after SMANCS administration. However, the resistance was not produced by serum prepared from mice at 8 h or 32 h after administration presumably because of the observation that the interferon activity was only demonstrated from 12 h to 28 h after SMANCS stimulation. When the serum specimens were treated with anti-IFN-gamma antiserum, the antitumor activity of the sera was abrogated. However, no significant change was detected in the antitumor activity of the specimens following treatment with anti-IFN-alpha/beta antiserum. Treatment of mice with SMANCS and anti-IFN-gamma antiserum together resulted in the elimination of the non-specific resistance to tumors. The IFN induced in the sera of mice by SMANCS was shown to be 57% IFN-gamma and 41% IFN-alpha/beta. Half of the interferon produced in SMANCS-stimulated mice could be eliminated by treatment with anti-IFN-gamma, and treatment of SMANCS-stimulated mice with both anti-IFN-gamma and anti-IFN-alpha/beta antisera resulted in a total absence of detectable interferon. These findings suggest that while the administration of SMANCS induces both IFN-gamma and IFN-alpha/beta production, in this case, it is only the former which mediates the non-specific resistance to tumors.

Animals↗

PubMed1989

Antimetastatic effect of endogenous tumor necrosis factor induced by the treatment of recombinant interferon gamma followed by an analogue (GLA-60) to synthetic lipid A subunit.

We have investigated the effect of endogenous production of tumor necrosis factor (TNF) induced by the combination of recombinant interferon gamma (rIFN gamma) as a primer followed by GLA-60 as a trigger (rIFN gamma/GLA-60) on murine lung metastases caused by B16-BL6 melanoma. In order to examine the therapeutic effect of endogenous TNF on tumor metastasis, the ability of multiple administrations of rIFN gamma/GLA-60 to induce TNF production was also tested. The multiple administrations of rIFN gamma/GLA-60 at intervals of 2 days were effective for the induction of endogenous TNF in mice but continuous multiple administrations of them for 2-4 days were not. In tumor-bearing mice, the production of endogenous TNF by rIFN gamma/GLA-60 was less than that of normal mice, but treatment 3 days after the surgical excision of primary tumors showed the endogenous TNF production to be similar to that in normal mice. In the experimental lung metastasis model, intravenous administration of rIFN gamma followed by intravenous or intranasal administration of GLA-60 showed potent inhibition of lung metastases of B16-BL6 melanoma, whereas the reverse sequence of administration (GLA-60/rIFN gamma) or administration of a mixture of rIFN gamma and GLA-60, which cannot induce the production of TNF, caused no inhibition of lung metastases. These results indicated that the regression of tumor metastases by rIFN gamma/GLA-60 was mediated by the production of endogenous TNF in addition to the direct effects of both immunostimulants. Furthermore, the administration of rIFN gamma and GLA-60 significantly inhibited the tumor metastases in spontaneous lung metastasis model. These results may provide a promising approach for the treatment of cancer metastasis as a result of its ability to induce endogenous TNF.

Adjuvants, Immunologic↗

PubMed1989

Automatic detection method of stenotic lesions in coronary cineangiograms.

A new image processing procedure enabling the automatic detection of coronary artery stenoses by cineangiography was developed. Detection of stenoses was performed using computer image processing by the following procedure. The path of the arteries was extracted by a subtraction method. The thresholding image was obtained from the subtraction image, and converted to a 'thinning' image, which represented the center line of the artery. For measurement of the arterial diameter, the vessel edges were determined by unilateral Gaussian fit to profile curves in sections perpendicular to the center line. Stenoses could then be detected on the basis of the normal diameter of artery estimated by Hough transformation. This method facilitates the detection of stenotic lesions from coronary cineangiograms.

Cineangiography↗

PubMed1989

Epithelial dysplasia produced by carcinogen pretreatment and subsequent wounding.

Golden hamsters in which the tongues were pretreated with DMBA for 4 weeks, subsequently excised, and either received no treatment or received additional postexcisional applications of acetone or DMBA for 9 to 13 days exhibited histologic evidence of epithelial dysplasia; these dysplastic lesions stained positive for papillomavirus genus-specific antigens. Conversely, animals in which the tongues received the same pretreatment yet had no excision failed to show any dysplastic changes, even though the tongues received additional applications of DMBA. Furthermore, papillomavirus genus-specific antigens were not demonstrable. The animals in which the tongues received no pretreatment with DMBA for 4 weeks followed by excisional wounding showed normal healing, even though the tongues were post-treated with DMBA. Papillomavirus genus-specific antigens could not be demonstrated in this last group.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1989

Conformational change and aggregation of concanavalin A at high temperatures.

Increase of the beta sheet content and aggregation of concanavalin A (con A) induced at about 60 C were followed with circular dichroism (c.d.) and scattered light intensity (I90) on both metal-complexed and demetallized species. The conversion occurred at a higher temperature for metal-complexed species than for demetallized one. A concentration-independent conversion curve of metal-complexed species, obtained for a concentration range below around 6 microgram/ml (6 x 10(-3) kg m-3) with a midpoint at 57 degrees C, was well described in terms of a conformational equilibrium between two conformers. However, aggregation did exist even at a low concentration of 1 microgram/ml. Aggregation also occurred without the conformational change as found at the initial stage or in Tris buffer, which suggested the absence of direct coupling between the conformational change and the aggregation. Changes of c.d. at 222 nm, expected to represent the main chain conformation, differed from those at 290 nm reflecting the environment of side chain chromophores. Time courses of three properties examined, c.d. at 222 nm, at 290 nm, and I90, always exhibited a lag in the case of metal-complexed species while the lag was not observed in the case of demetallized species, however. Lag became longer in c.d. but it became shorter in I90 as the protein concentration increased.

Circular Dichroism↗

PubMed1989

A mapping study of hypothalamic defensive attack and related responses in cats.

Effective stimulation sites for the hypothalamic defensive attach and its related responses were mapped in 65 tame adult cats (107 sites). The hypothalamic defensive attack was classified into two types according to its locomotion component: one with only directed attack and the other with retreat. The retreat appeared accompanied by back arching and intermingled with the directed attack. Otherwise, the directed attack and the retreat were accompanied by the same kinds of threat responses, including piloerection, ear retraction, growling and hissing. Stimulation sites for the directed attack with thresholds under 100 microA were located at the dorsal half of the ventromedial hypothalamic nucleus (VM) and areas just rostral to it. Directed attack with thresholds above 100 microA was elicited by stimulation of the marginal portion of the VM and adjacent areas, especially those rostral to it. Stimulation sites for the directed attack, which was replaced by stereotyped circling at higher intensities, were located at the part of the above-mentioned areas most distant from the VM. The retreat was elicited from the ventral half of the VM. Stimulation sites which evoked stereotyped circling with threat responses were distributed in a wider area of the medial hypothalamic area outside the VM.

Animals↗

PubMed1989

Adjuvant activities of synthetic lipid A subunit analogues and its conjugates with muramyl dipeptide derivatives.

We investigated the effects of the active principle of lipopolysaccharide (LPS), synthetic lipid A (compound 506), and of its related compounds GLA-60, -59 and -27, on murine macrophage activation and cytokine induction. GLA-60, which is devoid of endotoxic activity, showed interleukin-1 (IL-1)-inducing activity and activation of murine macrophages comparable to those of LPS or compound 506. The biological activities of six conjugates of GLA-60 with MDP derivatives GMD-323 to -328 were investigated in this study. All the GMD compounds except GMD-323 showed potent inducing activities for IL-1 and tumoricidal macrophages, especially GMD-324 and -326, which exhibited much higher activity than GLA-60. However, TNF- and CSF-inducing activities of these conjugates were lower than those of GLA-60. IL-1-inducing activity of the mixture of MDP derivative (GMD-267) and GLA-60 was higher than that of the conjugates (GMD-324) or that of GLA-60 and GMD-267 alone.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1989

Water in keratin. Piezoelectric, dielectric, and elastic experiments.

To investigate actions of water in keratin, the piezoelectric, dielectric, and elastic constants are measured at 10 Hz, at temperatures between -160 and 150 degrees C, and at various hydration levels. From changes in the piezoelectric, dielectric, and dynamic mechanical parameters with moisture content (m.c.), we have identified three regimes (I, II, and III) in the hydration of water for keratin. At high hydration (21% m.c.) around 0 degree C, the piezoelectric constants for keratin steeply decrease with increasing temperature. This may be attributed to interfacial polarization which is strongly related to self-associated water molecules (particularly regime III water) just around crystalline helical regions which can exhibit the stress-induced, i.e., piezoelectric, polarization and may be attributed to electrode polarization induced by the increase of mobile ions in the amorphous matrix region, some of which would be released from their trapped states just around the piezoelectric phase by the regime III water. With increasing hydration, the elastic constants for keratin are found to increase below -70 degrees C and decrease above -70 degrees C. This suggests a viscoelastic transition of the keratin structure due to bound water (regime II water). The piezoelectric, dielectric, and elastic loss peaks are found at around -120 degrees C for hydrated keratin, believed to be due to tightly bound water (regime I water), which acts only to stiffen the keratin structure. The adsorption regions of water in keratin are discussed by a piezoelectric two-phase model, which consists of piezoelectric and nonpiezoelectric phases. It is proposed that water molecule would at least adsorb in the nonpiezoelectric phase.

Elasticity↗

PubMed1989

Identification of human apolipoprotein E variant gene: apolipoprotein E7 (Glu244,245----Lys244,245).

Apolipoprotein E (apoE) is one of the protein moieties of the human serum lipoproteins. Three major isoforms of apoE (apoE2, apoE3, and apoE4) and minor variant isoforms (apoE1, apoE5, and apoE7) have been detected by isoelectric focusing. In this study we have cloned the apoE7 gene from a patient with the apoE3/E7 phenotype associated with hypertriglyceridemia and diabetes mellitus. DNA sequencing revealed that the apoE7 gene has two base substitutions (G----A) changing Glu244,245----Lys244,245, compared with the apoE3 gene. The replacement of the two amino acids is consistent with the result of isoelectric focusing of the apoE7 isoprotein, which shifts to four positively charged units compared with the apoE3 isoprotein.

Amino Acid Sequence↗

PubMed1989

Molecular cloning of a human apolipoprotein E variant: E5 (Glu3----Lys3).

Two types of apoE alleles from a genomic DNA library of a subject with the apoE2/E5 phenotype have been cloned. One of these alleles encodes an apoE isoprotein having cysteine, arginine, and cysteine at positions 112, 145, and 158 of mature apoE isoproteins, respectively, indicating an epsilon apoE2 allele. The other allele encodes a different isoprotein, having cysteine, arginine, and arginine at each of the above positions, respectively. In addition, this allele has a base substitution (G----A) which causes the substitution of lysine for glutamic acid at position 3 near the NH2-terminus of the mature apoE. This allele is a new variant, the epsilon apoE5 allele.

Amino Acid Sequence↗

PubMed1989

Measurement of distensibility of blood vessels using cineangiograms.

We developed a new, cineangiographic method to accurately measure the dynamic changes in the internal diameter of human arteries in vivo. Cine films were digitized at a spatial resolution of 4 microns/pixel, using a line image sensor. The vessel edges, with a Gaussian fit to a unilateral profile curve of the vessel, were determined with the aid of a computer program. We measured contrast-filled cylinder vessel models (2 to 7 mm in diameter) and evaluated precision, accuracy and linearity of the diameter measurement. A pulsatile vessel model of about 3.9 mm in internal diameter was used to examine the reliability of our method for detecting arterial wall motion. If the coefficient of variation of the vessel diameter determined cineangiographically was less than 2.2% we considered the cineangiograms sufficiently accurate to determine the internal vessel diameter and evaluate arterial distensibility.

Adult↗