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K Nishikawa

Publications and source records attributed to K Nishikawa.

At least 361 records · Page 20Linked to original sources
PubMed1994

[Expression of activation antigen, CD69, on human local eosinophils].

The activation antigen, CD69, has been shown to be expressed on activated lymphocytes. CD69 has also been shown to be associated with the signal transduction process. Recently, we demonstrated the expression of CD69 on lung eosinophils obtained from the bronchoalveolar lavage fluid of patients with eosinophilic pneumonia. In this study, we performed flowcytometric analysis of CD69 expression on eosinophils obtained from the bronchoalveolar lavage fluid, pleural effusion or peripheral blood of various patients. Whatever the disease, local eosinophils expressed significant levels of CD69, whereas most peripheral blood eosinophils did not express CD69. These findings suggest that CD69 is a marker for local eosinophils and that local eosinophils may differ functionally from peripheral blood eosinophils.

Adult↗
PubMed1994

[A case of ruptured left ventricular aneurysm due to syphilitic myocarditis].

This case involved a 20-year-old male who on May, 14, 1992, lost consciousness while working and went into a state of shock. He was taken to a hospital, where cardiac tamponade was diagnosed. He was later transferred to this hospital. Based on the results of echocardiography, coronary arteriography and left ventriculography, a ruptured ventricular aneurysm was diagnosed. The patient underwent emergency surgery. Serologic tests for syphilis performed at admission were definitely positive. Histopathological examination of the wall of the ventricular aneurysm disclosed fibrous myocarditis and peripheral coronary endarteritis accompanied by infiltration of plasma cells and lymphocytes. Immunohistological study revealed treponeme in the histiocytes of the aneurysmal wall. The diagnosis was a ruptured ventricular aneurysm caused by syphilitic myocarditis. Since the advent of penicillin therapy, cardiovascular syphilis, particularly syphilitic myocarditis, has become a rare disease. The chief interest of this case is that treponeme was detected in the lesion of myocarditis.

Adult↗
PubMed1994

Positive and negative selection for tumor necrosis factor responsiveness reveals an inhibitory role for EGF receptor in TNF-induced antiproliferation.

Tumor necrosis factor (TNF) induces dose-dependent, but incomplete cytotoxicity in ME-180 cervical carcinoma cells resulting in a significant reduction in cell viability. In this cell line there exists a characteristic residual tumor cell population that appears to be resistant to TNF. In order to investigate tumor cell heterogeneity and characteristics that correlate with their escape from TNF-induced cytotoxicity, TNF-resistant ME-180 cell variants (ME-180R) were isolated from a population of ME-180 cervical carcinoma cells (ME-180 parental). Incubation of ME-180 parental cells with TNF resulted in measurable changes in tumor cell DNA structural integrity and dose-dependent cytotoxicity, whereas ME-180R cell growth and DNA integrity were not effected by incubation with TNF. Binding of 125I-labeled TNF to a TNF-specific cell-surface receptor was measurable and equivalent on both ME-180R and ME-180 parental cells and both cell lines predominantly expressed the p55 form of the TNF receptor based upon flow cytometric analysis. Although both cell lines shared similar doubling times, intrinsic EGF receptor tyrosine kinase activity in ME-180R cells was found to be > 3-fold higher than that isolated from ME-180 parental cells. These results suggest that TNF-responsiveness may be mediated at a point subsequent to TNF binding and may be regulated, in part, by the expression of tyrosine kinase activity. To further explore this hypothesis, A431 vulvular carcinoma cells that express resistance to TNF were cloned and variants were isolated that escaped EGF-induced growth inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Squamous Cell↗
PubMed1993

Expression, purification and binding to the receptor of human insulin-like growth factor II.

Human insulin-like growth factor II (IGF-II) was expressed as a fused protein with 14 additive amino acids in Escherichia coli with a high yield by an expression system using T7 RNA polymerase. Purification of the expressed protein was simply performed using only differential ultrafiltrations, giving a homogeneous preparation upon polyacrylamide gel electrophoresis and high-performance liquid chromatography. The expressed peptide was reacted with a monoclonal antibody raised against native IGF-II on a blotted membrane. Furthermore, the peptide was bound to IGF-II receptor in solubilized rat fetus membrane, though the affinity was slightly inferior to that of native IGF-II. In addition, fusion IGF-II immobilized on a gel matrix was useful for one-step purification of the IGF-II receptor with a high yield from solubilized rat fetus membranes.

Amino Acid Sequence↗
PubMed1993

Mobilization of acyl chains from endogenous cellular phospholipids into cholesteryl esters during foam-cell formation in mouse peritoneal macrophages.

We previously showed that phosphatidylserine-containing liposomes (phosphatidylserine liposomes) are effectively metabolized and induce foam-cell formation in cultured macrophages (Nishikawa, K., Arai, H. and Inoue, K. (1990) J. Biol. Chem. 265, 5226-5231). When cultured mouse peritoneal macrophages were incubated with phosphatidylserine liposomes of different cholesterol content, cholesteryl esters were formed in the cells in proportion to the cholesterol content of the liposomes added to the culture. Cholesteryl esters were formed only when the cells took up more than a certain amount of cholesterol (approx. 160% above the basal cell level). Fatty acyl moiety derived from the exogenous phospholipids were utilized preferentially for cholesteryl ester formation. Once cholesterol as an acceptor is exhausted within cells, the acyl chain may be utilized for triacylglycerol formation. Not only exogenous lipid acyl chains but also endogenous phospholipid acyl chains were also utilized for cholesteryl ester and triacylglycerol formation under the present conditions, since the radioactivity in phospholipids was incorporated into both cholesteryl esters and triacylglycerols in macrophages whose endogenous phospholipids had been prelabeled with radioactive fatty acids. Among phospholipid classes, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol served as the acyl donor, whereas sphingomyelin and cardiolipin did not. Mobilization of acyl chains from endogenous phospholipids to the neutral lipid fraction was also observed during foam-cell formation induced by acetyl low-density lipoprotein. The substance(s) produced within cell in the process of foam-cell formation may trigger the acyl chain mobilization from endogenous phospholipids.

Animals↗
PubMed1993

Nonpeptide angiotensin II receptor antagonists. Synthesis and biological activity of potential prodrugs of benzimidazole-7-carboxylic acids.

In order to improve the oral bioavailability (BA) of 2-butyl-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-benzimid azole - 7-carboxylic acid (3: CV-11194) and 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4- yl]methyl]-1H-benzimidazole-7-carboxylic acid (4: CV-11974), novel angiotensin II (AII) receptor antagonists, chemical modification to yield prodrugs has been examined. After selective tritylation of the tetrazole rings in 3 and 4, treatment of N-tritylated benzimidazole-7-carboxylic acids (6, 7) with a variety of alkyl halides, followed by deprotection with hydrochloric acid, afforded esters of 3 and 4. Mainly 1-(acyloxy)alkyl esters and 1-[(alkoxycarbonyl)oxy]alkyl esters, double ester derivatives, were synthesized. Their inhibitory effect on AII-induced pressor response in rats and oral BA were investigated. (Pivaloyloxy)methyl and (+/-)-1-[[(cyclohexyloxy)-carbonyl]oxy]ethyl esters of 3 and 4 showed marked increases in oral bioavailability which significantly potentiated the inhibitory effect of the parent compounds on AII-induced pressor response. Among them, (+/-)-1-[[(cyclohexyloxy)carbonyl]oxy]ethyl 2- ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-benzimida zole- 7-carboxylate (10s, TCV-116) was selected as a candidate for clinical evaluation.

Administration, Oral↗
PubMed1993

Nonpeptide angiotensin II receptor antagonists. Synthesis and biological activity of benzimidazolecarboxylic acids.

A series of 2-substituted-1-[(biphenyl-4-yl)methyl]-1H-benzimidazole-7- carboxylic acids was prepared from the key intermediate 3-amino-2-[[(biphenyl-4- yl)methyl]amino]benzoate (6a-c) in order to clarify the structure-activity relationships of various analogues of 2-butyl-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-ben zimidazole- 7-carboxylic acid (CV-11194), a potent and long acting angiotensin II (AII) receptor antagonist. The AII antagonistic activity of the benzimidazoles was investigated by in vitro assays, which included an AII receptor binding assay and AII-induced vasocontraction assay, as well as by in vivo assays such as an AII-induced pressor response in rats. Most of the benzimidazoles showed high affinity for the AII receptor (IC50 value, 10(-6)-10(-7) M) and inhibited the AII-induced pressor response at 1 or 3 mg/kg po, and the effects were more potent than those of CV-11194 and DuP 753. The structure-activity relationship studies on the binding affinity and the inhibition of AII-induced pressor response suggested that straight chains of a certain length (e.g., ethoxy groups, ethyl groups) were the best as substituents at the 2-position and that their steric factors, lipophilicity, and electronic effects affected the potency of the AII antagonistic action. Both a carboxyl group at the 7-position and a tetrazole ring at the 2'-position were particularly important for potent and orally active AII antagonistic activity and a long-acting hypotensive effect. The representative compound, 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H- benzimidazole-7-carboxylic acid (26b, CV-11974), inhibited the specific binding of [125I]AII to bovine adrenal cortical membrane with an IC50 value of 1.1 x 10(-7) M. The AII-induced contraction of rabbit aortic strips was antagonized by CV-11974 (IC50 value, 3.0 x 10(-10) M). Oral administration of CV-11974 to conscious normotensive rats at 1 mg/kg resulted in long-lasting inhibition of the AII-induced pressor response. CV-11974 at 0.1-1 mg/kg iv reduced blood pressure dose-dependently in spontaneously hypertensive rats.

Angiotensin Receptor Antagonists↗
PubMed1993

Inhibition of rabbit aortic angiotensin II (AII) receptor by CV-11974, a new nonpeptide AII antagonist.

The angiotensin II (AII) antagonistic action of CV-11974 (2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl] benzimidazole-7-carboxylic acid) was investigated in an AII-receptor binding assay using rabbit aortic membranes and an AII-induced contraction assay using rabbit aortic strips. A single class of [125I]AII-(Sar1,Ile8) binding sites was found in the membranes with a dissociation constant (Kd) of 0.15 nM and a receptor concentration (Bmax) of 86.9 fmol/mg protein. CV-11974 markedly reduced Kd without affecting Bmax. The specific binding of [125I]AII-(Sar1,Ile8) in this preparation was inhibited completely by CV-11974 [the inhibition constant (Ki) = 0.64 nM], DuP 753 [an angiotensin II type I (AT1) receptor-selective antagonist] (Ki = 51 nM) and EXP3174 (an active metabolite of DuP 753) (Ki = 6.8 nM), but was not affected by PD123177 (an AT2 receptor-selective antagonist). These results suggest that the single binding site in rabbit aortic membranes is an AT1 receptor subtype. The affinity of CV-11974 to these AT1 receptors was approximately 80 and 10 times higher than that of DuP 753 and EXP3174, respectively. CV-11974 showed no appreciable affinity for the AT2 receptors found in bovine cerebellum. In the in vitro functional study, CV-11974 markedly reduced the AII-induced maximal contractile response of rabbit aortic strips (pD'2 = 9.97). In contrast, Compound 7-H, which lacks the carboxyl group at the benzimidazole ring of CV-11974, inhibited the contraction in a competitive manner. The inhibition by CV-11974 was long lasting. These results suggest that CV-11974 is a potent and long-acting AT1 receptor-selective, competitive antagonist. The carboxyl group at the benzimidazole ring plays an important role in the interaction between CV-11974 and the AT1 receptor.

Angiotensin II↗
PubMed1993

Nonpeptide angiotensin II receptor antagonists. Synthesis and biological activity of benzimidazoles.

A series of substituted 2-butylbenzimidazoles bearing a biphenylylmethyl moiety at the 1-position was prepared via three synthetic routes and evaluated for angiotensin II (AII) receptor antagonistic activity (in vitro and in vivo). Binding affinity was determined using bovine adrenal cortical membrane. Substitution at the 4-, 5-, or 6-position reduced the affinity relative to that of the unsubstituted compound (13a). However, most of the compounds with a substituent at the 7-position showed binding affinity comparable to that of DuP 753 (losartan). In functional studies, a carboxyl group was found to be very important for antagonistic activity against AII. Comparison of 2-butyl-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]- 1H-benzimidazole-4-, -5-, -6-, and -7-carboxylic acids (15a-d) in an AII-induced rabbit aortic ring contraction assay clearly demonstrated the importance of the substitutional position of the carboxyl group. In an in vivo assay, oral administration of benzimidazole-7-carboxylic acids caused long-lasting inhibition of the AII-induced pressor response in rats. The optimum substituent at the 7-position of the benzimidazole ring was found to be a carboxyl or an ester group. The representative compound, 2-butyl-1-[[2'- (1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-benzimidazole-7-carboxy lic acid (15d, CV-11194), inhibited the specific binding of [125I]AII to bovine adrenal cortical membrane with an IC50 value of 5.5 x 10(-7) M. The AII-induced contraction of rabbit aortic strips was antagonized by CV-11194 (IC50 value, 5.5 x 10(-11) M), while the compound had no effect on the contraction induced by norepinephrine or KCl. Orally administered CV-11194 at doses of 0.3-10 mg/kg dose-dependently inhibited the AII-induced pressor response in rats and dogs. CV-11194 at 1 mg/kg po reduced blood pressure in spontaneously hypertensive rats (SHR). The three-dimensional molecular structure of CV-11194 was determined by X-ray diffraction.

Adrenal Cortex↗
PubMed1993

Suppressive effect of transforming growth factor-beta on the phosphorylation of endogenous substrates by conventional and novel protein kinase C in primary cultured mouse epidermal cells.

The effect of transforming growth factor-beta (TGF-beta) on the endogenous protein phosphorylation caused by phorbol 12-myristate 13-acetate (PMA), a potent activator of protein kinase C (PKC), was examined in primary cultured mouse epidermal cells. PMA markedly stimulates phosphorylation of endogenous proteins, i.e. KP-1 and KP-2, through Ca(2+)-dependent conventional PKC (cPKC), and KP-10 through Ca(2+)-independent novel PKC (nPKC) in intact epidermal cells. TGF-beta strongly suppressed the PMA-stimulated phosphorylation of these three proteins. Rate of dephosphorylation of these phosphorylated proteins was not affected by TGF-beta. Treatment of epidermal cells with TGF-beta decreased cPKC activity both in cytosolic and particulate fractions, but not nPKC activity. These results indicate that TGF-beta suppresses cPKC- and nPKC-mediated endogenous protein phosphorylation in intact epidermal cells, but the mechanisms of suppression are different.

Animals↗
PubMed1993

Inhibitory effect of TCV-309, a novel platelet activating factor (PAF) antagonist, on endotoxin-induced disseminated intravascular coagulation in rats: possible role of PAF in tissue factor generation.

The possible involvement of platelet activating factor (PAF) in the pathogenesis of endotoxin-induced disseminated intravascular coagulation (DIC) was investigated in rats using a novel potent PAF antagonist, TCV-309. TCV-309 (> 1 mg/kg, i.v.) showed beneficial effects in rats with experimental DIC induced by a 4-hour sustained infusion of endotoxin (1 mg/kg) in a dose-dependent manner. TCV-309 (1 mg/kg) significantly ameliorated the decrease in platelet count and plasma fibrinogen, the prolongation of prothrombin time (PT) and activated partial thromboplastin time (APTT) and the increase in fibrin and fibrinogen degradation products (FDP) and inhibited glomerular fibrin deposition. Furthermore, plasma tissue factor (TF) activity was greatly increased in the DIC rats, and this was also significantly decreased by TCV-309 (1 mg/kg). TCV-309 (1 mg/kg) did not affect these parameters in normal rats. A 4-hour sustained infusion of PAF (60 micrograms/kg) caused mild but significant changes in some DIC parameters such as PT, fibrinogen and FDP concentration and increased the plasma TF activity. TCV-309 (1 mg/kg) inhibited all these PAF-induced changes. TCV-309 (0.1 mM) itself had no direct in vitro effects on the blood coagulation system including TF activity. These results strongly suggest that PAF plays a role in the pathogenesis of endotoxin-induced DIC via the generation of TF. Prophylactic use of PAF antagonists may therefore be useful for the treatment of DIC with sepsis.

Animals↗
PubMed1993

Antibodies to intercellular adhesion molecule 1/lymphocyte function-associated antigen 1 prevent crescent formation in rat autoimmune glomerulonephritis.

In patients with glomerulonephritis widespread crescents are associated with a poor prognosis. Crescent formation appears to depend on the migration of mononuclear cells into Bowman's space, and therefore the interaction between leukocytes and glomerular endothelium may be a critical event in the genesis of crescents. We performed the present study to determine the effects of mouse monoclonal antibodies to the adhesion molecules intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) in a model of crescentic glomerulonephritis in Wistar-Kyoto rats, induced by immunization with bovine glomerular basement membrane (GBM). By 10-14 d after immunization, the rats had developed circulating anti-GBM antibodies, reactive with the alpha 3 chain of type IV collagen (the Goodpasture antigen), accompanied by proteinuria, accumulation of rat immunoglobulin (Ig)G in the GBM, increased expression of ICAM-1 by glomerular endothelial cells, infiltration of glomerular tufts with LFA-1+ T cells and monocyte/macrophages, and early crescents. At 5 wk all rats had diffuse fibrocellular crescents, glomerular sclerosis, and tubulointerstitial damage. All rats developed severe renal insufficiency and died by 5 or 6 wk. The administration of monoclonal antibodies to rat ICAM-1 and LFA-1 markedly decreased the severity of the renal disease. In a group of rats injected three times a week with the monoclonal antibodies, from 2 d before immunization with GBM to day 14, glomerular abnormalities and proteinuria were virtually absent at day 14; even at 5 wk glomerular disease was quite mild, with only slight crescent formation and with only a mild decrease in renal function. When treatment was continued until 5 wk, the beneficial effects were even more marked, with virtual absence of crescents and with preservation of normal renal function. In a group of rats in which treatment was initiated on day 14, shortly after the appearance of glomerular abnormalities, progression of the disease was appreciably retarded, and the decrease in renal function was inhibited. The kidneys of rats treated from days -2 to 14 with antibodies to ICAM-1 and LFA-1 showed bright linear staining for rat IgG along the GBM, which did not differ in intensity from that seen in untreated rats. Furthermore, the titers of anti-GBM antibodies at 2 wk in treated rats were not lower than that seen in most of the untreated rats. There was, however, moderate reduction of anti-GBM antibodies at 5 wk in the treated rats.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Human high molecular weight kininogen binds to human umbilical vein endothelial cells via its heavy and light chains.

High molecular weight kininogen (HK) is a multifunctional plasma glycoprotein that occupies a critical position in pathways that link inflammation and coagulation. Excision of the vasoactive peptide bradykinin by plasma kallikrein results in kinin-free HK that consists of a 65-Kd N-terminal heavy chain (HK-HC) linked to the C-terminal 45-Kd light chain (HK-LC) by a disulfide bridge. HK-HC is an inhibitor of SH-proteases and HK-LC contains the binding sites for coagulation cofactors prekallikrein and factor XI. HK has previously been shown to bind specifically to human umbilical vein endothelial cells (HUVEC) in a zinc(2+)-dependent manner by a single class of high-affinity binding sites. We have further characterized that interaction in order to determine the cell-binding regions of HK. Competition binding experiments have indicated that either HK-LC or HK-HC was able to inhibit the binding of labeled HK with a 50% inhibitory concentration (IC50) of 77 nmol/L and 89 nmol/L, respectively. Cleaved two-chain HK (HKa) had an IC50 of 73 nmol/L, whereas uncleaved HK had an IC50 of 335 nmol/L. Direct binding experiments have indicated that HUVEC bind both purified [125I]HK-HC and [125I]HK-LC in a zinc(2+)-dependent manner and that HK-LC did not displace bound HK-HC. The light chain of low molecular weight kininogen or prekallikrein-binding region of HK did not inhibit the binding of HK to HUVEC. Our results, therefore, indicate that (1) HK is capable of binding to endothelial cells via both heavy and light chain moieties, (2) HKa has a higher affinity to HUVEC, and (3) purified heavy and light chains are capable of directly binding to HUVEC. The data are consistent with the presence of a single high-affinity site for HK on endothelial cells within which are subsites that bind to heavy and light chains.

Binding Sites↗
PubMed1993

Double-negative (CD4- CD8-) T cells from adult T-cell leukemia patients also have poor expression of the T-cell receptor alpha beta/CD3 complex.

We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN-ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Adult↗
PubMed1993

A geometrical constraint approach for reproducing the native backbone conformation of a protein.

It is known that the backbone conformation of a protein can be reproduced with precision once a correct contact map (two-dimensional representation showing residue pairs in contact) is given as geometrical constraints. There is, however, no way to infer the correct contact map for a protein of unknown structure. We started with one-dimensional constraints using the quantity N14 (the number of neighboring residues within the radius of 14 A). Since the plot of N14 along a chain shows a good correlation with the corresponding amino acid sequence, the N14 profile obtained from the X-ray structure is predictable from the sequence. Construction of backbone conformations under a given N14 profile was carried out in the following two steps: (1) a contact map from the N14 profile was produced by taking the product of N14 values of every two residues; (2) backbone conformations were generated by applying the distance geometry technique to distance constraints given by the contact map. If present, disulfide bonds in a protein, as well as the secondary structure, were treated as additional constraints, and both cases with or without the additional information were examined. The method was tested for 11 proteins of known structure, and the results indicated that the reproduced conformation was fairly good, using an X-ray structure for comparison, for small proteins of less than 80 residues long. The basic assumption and effectiveness of the present method were compared with those of previous studies employing the geometrical constraint approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗