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S Iwasa

Publications and source records attributed to S Iwasa.

At least 37 records · Page 2Linked to original sources
PubMed2000

Corresponding distributions of increased endothelin-B receptor expression and increased endothelin-1 expression in the aorta of apolipoprotein E-deficient mice with advanced atherosclerosis.

Endothelin (ET)-1 causes proliferation of vascular smooth muscle cells (VSMC). Although it has been reported that stimulation of ET(B) receptors as well as ET(A) receptors promote proliferation of VSMC, the precise distribution of each receptor subtype in atherosclerotic vessels is unknown. Previous studies demonstrated that apolipoprotein E (apoE)-deficient mice have hypercholesterolaemia and develop severe atherosclerosis. To investigate the pathophysiological roles of vascular ET system in atherosclerosis, we examined preproET-1 messenger ribonucleic acid expression in the aorta of apoE-deficient mice, and performed immunohistochemical staining for ET-1 and each ET receptor subtype (ET(A) and ET(B) receptors) in the atherosclerotic lesions of these mice. The level of preproET-1 mRNA in the aorta was significantly higher in the apoE-deficient mice than in the control mice. Strong ET-1 staining was observed in the macrophage-foam cells, intimal and medial VSMC in the atherosclerotic lesions of the apoE-deficient mice. In addition, in the atherosclerotic lesions, strong ET(B) receptor staining was observed in the macrophage-foam cells, intimal and medial VSMC, which distribution corresponded closely to that of ET-1. ET(A) receptor staining was observed in the medial VSMC of both groups, but not in the macrophage-foam cells of the apoE-deficient mice. ET(A) receptor staining in the medial VSMC was stronger in the apoE-deficient mice than in the control mice. These results suggest that the vascular ET system, including ET-1 and ET receptors, is activated in the atherosclerotic lesions of apoE-deficient mice. Since the distribution of strong ET(B) receptor staining corresponded closely to that of ET-1, it is suggested that the ET system, mediated by ET(B) receptors, has an important role in the pathophysiology of the atherosclerotic lesions of apoE-deficient mice.

Animals↗
PubMed2000

Role of endothelin-1 in atherosclerosis.

Increased evidence has shown that endothelin-1 (ET-1) derived from the arterial cells is involved in the development of atherosclerosis. ET-1 and ET receptors are upregulated in both human and experimental animal atherosclerotic lesions. Plasma ET-1 levels are significantly elevated in hypercholestolemic subjects and cholesterol-fed animals. We hypothesized that plasma lipoproteins such as LDL and HDL retained in the arterial wall can affect ET-1 production and secretion, thereby sustaining vascular functions. Using a two-chamber culture system, we have demonstrated that endothelial cells (ECs) show a polar secretion of ET-1; the majority of ET-1 are secreted toward the basal side of the vessels. Furthermore, we found that LDL enhances whereas HDL inhibits the ET-1 secretion from ECs in a polarized pattern. In order to demonstrate ET receptor distribution in the lesion, we recently studied both human and apoE-KO mice. Our study showed that there is an increased expression of ETB receptors in foamy macrophages in the lesions. More importantly, medial smooth muscle cells (SMCs) beneath the foam cell lesions exhibited a higher intensity of ETB receptor immunoreactivity than those located in foam cell-free areas. In such an area, ET-1 immunoreactivity is also increased. These results suggest that accumulation of foamy macrophages may modulate the shift of ET receptor subtypes from ETA to ETB in SMCs and an enhanced ET system mediated by ETB receptors may play a pivotal role in the progression of atherosclerosis. This notion has been further supported by a recent finding that administration of ET receptor antagonists resulted in a significant reduction of atherosclerosis in apoE-KO mice.

Animals↗
PubMed2000

[Clinical efficacy of cefpirome sulfate against Bacteroides species, Prevotella species and Porphyromonas species. Society of Anaerobic Bacterial Infections in the fields of obstetrics and gynecology in Gifu].

The injectable cephalosporin cefpirome (CPR) was launched in Japan in 1993. It has widely been used in the various infectious diseases. We therefore studied the clinical and bacteriological efficacy of CPR against infections caused by Bacteroides species, Prevotella species and Porphyromonas species frequently isolated from the obstetric and gynecologic infections. Thirteen institutions were involved in this study which ran from March 1994 to January 1999. The administration dosage of CPR was 2 to 4 gram per day administered by drip infusion or intravenous infusion. The duration of treatment was from 3 to 15 days. The evaluations were performed before and after the treatment. CPR was administered to 194 patients with obstetric and gynecologic infections, and 146 of 194 cases were acceptable for the evaluation of drug efficacy. Bacteroides species were identified in 102 patients. Clinical efficacy in 146 cases was excellent in 12 patients, good in 110, fair in 9 and poor in 15 patients. The eradication rate for Bacteroides species could be in 37 cases out of 54 evaluable cases; Prevotella species in 38 out of 49; and Porphyromonas species in 5 out of 5. The overall assessment of bacteriological efficacy was "eradicated" in 91 cases out of 133 (68.4%). Adverse reactions including abnormal findings in laboratory tests were seen in 8 patients (4.76%). Based on these results, CPR promises efficacy and safety in the treatment of obstetric and gynecologic infections due to Bacteroides species.

Adult↗
PubMed1999

Peroxiredoxin I expression in human thyroid tumors.

Peroxiredoxin I (Prx I) is newly discovered oxidative stress inducible protein, having a thioredoxin peroxidase activity. The Prx I expression level in 107 samples out of 60 thyroid lesions, including normal thyroid, tumors and thyroiditis including Graves' disease were examined using immunoblotting. Prx I expression levels in follicular neoplasm (P = 0.00005) and thyroiditis group (P = 0.0037) were significantly higher than that of the control group, while papillary carcinoma group did not show statistical significance. Immunohistochemistry indicated that Prx I was in epithelial cells of thyroid follicles. These results suggest that Prx I is expected to be a candidate for novel tumor markers to discriminate tissue types of tumors.

Adult↗
PubMed1999

Heme oxygenase-1 expression in oral squamous cell carcinoma as involved in lymph node metastasis.

Thirty-eight oral squamous cell carcinomas (SCCs) were semi-quantitatively analyzed by immunohistochemical staining, and the relation between heme oxygenase-1 (HO-1) expression and the clinical status were correlated. High immunostaining of HO-1 was detected in lymph node metastasis negative groups (P = 0.0018) and in well-differentiated SCCs (P = 0.0016). There were no significant correlations between heme oxygenase-1 expression and other factors, such as size of the tumor, staging, age and sex. These findings further support the proposition that high heme oxygenase-1 expression in oral SCCs can be useful in identifying patients at low risk of lymph node metastasis.

Adult↗
PubMed1999

Increased immunoreactivity of endothelin-1 and endothelin B receptor in human atherosclerotic lesions. A possible role in atherogenesis.

This study was designed to analyze the distribution and localization of endothelin-1 (ET-1) and ET receptors (ET(A) and ET(B)) at different stages of human atherosclerotic lesions by immunohistochemistry. Compared with ET(A) receptors, there was increased immunoreactivity of ET-1 and ET(B) receptor in both unfoamy and foamy macrophages and T lymphocytes in fatty streak and fibrous plaque lesions. In addition, medial SMCs located just beneath the foam cell lesions revealed a higher intensity of ET(B) receptor immunoreactivity than those located beneath the normal-looking intima without foam cells. In fibrous plaques, intimal SMCs near foam cells showed an increased density of ET receptors with predominant ET(B) immunoreactivity. In the areas where SMCs showed ET(B) receptor, ET-1 immunoreactivity was also enhanced. These results suggest that accumulation of foamy macrophages and T lymphocytes may modulate the switching of ET receptor subtypes from ET(A) to ET(B) in vascular SMCs. and that the enhanced ET system mediated by ET(B) receptors may play active roles in the progression of atherosclerosis.

Adolescent↗
PubMed1999

Degranulation of eosinophils mediated by intercellular adhesion molecule-1 and its ligands is involved in adhesion molecule expression on endothelial cells-selective induction of VCAM-1.

BACKGROUND: Adhesion molecules and eosinophils may play an important role in the pathogenesis of allergic inflammatory reactions. OBJECTIVE: We attempted to clarify eosinophil activation, such as degranulation, by signaling through adhesion molecule and to determine whether degranulation is involved in adhesion molecule expression on endothelial cells. METHODS: Eosinophils were cultured with or without recombinant soluble intercellular adhesion molecule-1 (ICAM-1), and the levels of eosinophil cationic protein and eosinophil-derived neurotoxin were determined. The influence of these eosinophil granule proteins or supernatant from eosinophil cultured with ICAM-1 on the expression of ICAM-1 or vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells was also examined by flow-cytometric analysis. RESULTS: Supernatant levels of eosinophil granule protein were significantly increased by culture for 4 hourss or 16 hours with recombinant soluble ICAM-1, suggesting degranulation by adherence to ICAM-1. Both granule proteins and the supernatants of eosinophils cultured with recombinant soluble ICAM-1 induced expression of ICAM-1 and VCAM-1 on endothelial cells, with the latter showing a more prominant increase. CONCLUSION: Degranulation mediated through adherence to endothelial cells by ICAM-1 and its ligands may be involved in the expression of adhesion molecules, such as ICAM-1 or VCAM-1, on these cells. Our finding of the selective induction of VCAM-1 expression suggests that eosinophil adherence to endothelial cells, even if it is because of ICAM-1, may be involved in selective eosinophil recruitment and accumulation at sites of allergic inflammation.

Cell Adhesion Molecules↗
PubMed1998

Evaluation of oral mucoadhesive microspheres in man on the basis of the pharmacokinetics of furosemide and riboflavin, compounds with limited gastrointestinal absorption sites.

When sustained-release adhesive and non-adhesive microspheres which release the same drugs at similar rates are administered orally, drug absorption after administration of adhesive microspheres should, if the gastrointestinal residence of adhesive microspheres is prolonged as a result of mucoadhesion, be higher than that after administration of non-adhesive microspheres. The gastrointestinal transit of oral adhesive microspheres in man has been evaluated pharmacokinetically using furosemide and riboflavin, compounds with limited absorption sites in the upper small intestine. In a preliminary experiment with fasted rats it was confirmed that a higher percentage of the drug remained in the stomach and that plasma drug levels were higher when furosemide was administered in the form of adhesive rather than non-adhesive microspheres. Two kinds of sustained-release microsphere, adhesive and non-adhesive, containing furosemide and riboflavin in hard gelatin capsules were prepared and orally administered to 10 healthy fasted volunteers in a cross-over design. Areas under the plasma concentration-time curves (AUC) were 1.8 times larger for furosemide and urinary recovery was 2.4 times higher for riboflavin when adhesive microspheres rather than when non-adhesive microspheres were used. When adhesive microspheres containing riboflavin were administered to fed volunteers, urinary recovery was 2.1 times higher and mean residence time (MRT) was more prolonged than when the microspheres were administered to fasted volunteers. Adhesive microspheres were found to adhere to the gastric or intestinal mucosa with high affinity in man and rats, resulting in prolonged gastrointestinal residence.

Adhesives↗
PubMed1997

Efficient production of a functional mouse/human chimeric Fab' against human urokinase-type plasminogen activator by Bacillus brevis.

Expression/secretion vectors for the production of Fab' and single-chain (sc) Fab' by Bacillus brevis have been constructed. For the production of Fab', the cDNAs encoding the L chain and Fd' fragment (Fd with the hinge region) of a mouse-human chimeric Fab' against human urokinase-type plasminogen activator were fused directly with the translation-start and signal-peptide-encoding regions of the mwp gene, the gene for one of the major cell-wall proteins of Bacillus brevis. The two fused genes were placed tandemly downstream from the promoter of the cell-wall protein gene operon (cwp) of B. brevis. For the production of scFab', the two cDNAs were linked with a synthetic oligonucleotide encoding a flexible peptide linker of 17 or 24 amino acids, and fused with the translation start and signal-peptide-encoding regions of the mwp gene. Fab' was efficiently produced by B. brevis, being accumulated at a level of 100 mg/l in the culture medium in a simple shake-flask culture, which is the highest level obtained so far for a gram-positive bacterium. On the other hand, the scFab' remained at a level of a few milligrams per liter in the culture medium. The Fab' produced by B. brevis showed comparable antigen-binding activity to that of the parental antibody. The L chain and Fd' fragment, constituting the Fab', had the correct N-terminal amino acid sequences. These results indicate that B. brevis is a very promising host for the production of native Ig fragments.

Amino Acid Sequence↗
PubMed1997

Utilization of an amorphous form of a water-soluble GPIIb/IIIa antagonist for controlled release from biodegradable microspheres.

PURPOSE: We prepared injectable microspheres for controlled release of TAK-029, a water-soluble GPIIb/IIIa antagonist and discussed the characteristics of controlled release from microspheres. METHODS: Copoly(dl-lactic/glycolic)acid (PLGA) microspheres were used for controlled release of TAK-029 [4-(4-amidinobenzoylglycyl)-3-methoxycarbonyl-2-oxopiperazine++ +-1-acetic acid]. They were prepared with a solid-in-oil-in-water (S/O/W) emulsion solvent evaporation technique using either a crystalline form or an amorphous form of the drug. RESULTS: An amorphous form of TAK-029 gave more homogeneous S/O dispersion and higher viscosity than its crystalline form when added to dichloromethane solution of PLGA, resulting in a high drug entrapment into microspheres and a well-controlled release of the drug. Additions of sodium chloride into an external aqueous phase and L-arginine into an oil phase also increased entrapment of the drug, and reduced initial burst of the drug from the microspheres. The microspheres demonstrated a desirable plasma level profile in therapeutic range (20-100 ng/ml) for 3 weeks in rats after single subcutaneous injection. CONCLUSIONS: A well-controlled release of TAK-029, a water-soluble neutral drug, with small initial burst was achieved by utilizing its amorphous form as a result of possible interaction with PLGA and L-arginine.

Animals↗
PubMed1996

Cellular uptake mechanism for oligonucleotides: involvement of endocytosis in the uptake of phosphodiester oligonucleotides by a human colorectal adenocarcinoma cell line, HCT-15.

We used a 20-mer antisense oligonucleotide against human MDR1 mRNA to study the mechanism of uptake of oligonucleotides by a human colorectal adenocarcinoma cell line, HCT-15.5'-end-32P-labeled oligonucleotides were mainly used. The uptake of phosphodiester oligonucleotides (D-oligo) by HCT-15 cells increased with time, but the uptake of phosphorothioate oligonucleotides (S-oligo) showed minimal increases with time. HeLa cells showed a 4-fold greater D-oligo uptake than did HCT-15 cells, and other cell lines exhibited a 25-fold lower uptake than did HCT-15 cells. On the other hand, S-oligo uptake varied only severalfold among the cell lines used. Doligo up-take consisted of a saturable component (Michaelis constant K(m) = 0.16 microM and maximal uptake rate Vmax = 4.8 pmol/min/mg for HCT-15 cells and K(m) = 0.21 microM and Vmax = 35.6 pmol/min/mg for HeLa cells), i.e., the difference between the cell types was mainly in Vmax. The uptake of labeled D-oligo was inhibited by unlabeled S-oligo at a much lower concentration (Ki = 0.01 microM) than by unlabeled D-oligo (K(m) = 0.16 microM), although the uptake rate of D-oligo was greater than that of S-oligo. The D-oligo uptake was highly temperature dependent. Of the sulfhydryl-modifying reagents (p-chloromercuriphenyl-sulfonic acid and p-chloromercuribenzoic acid), only p-chloromercuribenzoic acid inhibited D-oligo uptake, suggesting the involvement of a protein whose sulfhydryl residues inside the cell are critical for D-oligo uptake. Chloroquine and monensin, which are known to alter the intracellular fate of ligands and receptors, did not affect D-oligo uptake, but phenylarsine oxide, an inhibitor of internalization processes, inhibited uptake significantly. Down-regulation and recovery of D-oligo uptake induced by excess unlabeled D-oligo pretreatment occurred, but this was only partial. Studies with a digitonin equilibrium method and confocal microscopy indicated that intracellular localization of D-oligo was mainly in a vesicular compartment. More stable 3'-end-32P-labeled oligonucleotides were also used, to compare their uptake characteristics with those of the 5'-end-labeled oligonucleotides. The uptake characteristics for the two labels were similar in terms of saturability, greater D-oligo uptake, compared with S-oligo, and the inhibitory effect of p-chloromercuribenzoic acid; however, the stable 3'-end label showed greater uptake than the 5'-end label. Our findings suggest that D-oligo uptake by HCT-15 cells is mediated by endocytosis involving binding sites on the plasma membrane.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1995

Efficient production of anti-(hepatitis B virus) antibodies and their neutralizing activity in chimpanzees.

For industrial production of human monoclonal antibodies (hmAb) against hepatitis B virus surface antigen (HBsAg), we scaled-up a short-term perfusion culture in serum-free medium, which was chosen as the most suitable culture method, to a 50-1 fermentor equipped with a rotating shear filter. Using hydrophobic chromatography as the initial step of hmAb purification, the mAb HBW4, HBW6 and W471 were isolated in good quality from the respective culture broths in yields of approximately 75%. Each of the three purified hmAb alone, and a cocktail of the three, protected chimpanzees against HB virus, when injected intravenously 3 h after viral challenge, as long as the serum antibody levels were significant. A pharmacokinetic study using cynomolgus monkeys demonstrated that the hmAb have a long plasma half-life and bioavailability of approximately 76% upon intramuscular injection in primates. Thus, anti-HBsAg hmAb produced by an industrial process are expected to be successfully used in clinical fields.

Animals↗
PubMed1995

A sensitive ELISA for the characterization of two forms of circulating intercellular adhesion molecule-1 in human plasma.

Nine murine monoclonal antibodies (MAbs) raised against recombinant soluble intercellular adhesion molecule-1 (sICAM-1) were evaluated by means of ELISAs, and their neutralizing activity was investigated in two bioassays employing Raji cells activated with phorbol myristate acetate. Three of the MAbs inhibited autoaggregation of the activated cells and adhesion to sICAM-1 fixed on a plastic plate. Non-neutralizing antibody SM1-255 is directed to an epitope that was not recognized by the other eight MAbs. This property enabled us to develop two ELISAs employing SM1-255 as a liquid-phase antibody for the quantitation of sICAM-1 circulating (cICAM-1) in human plasma. One assay, employing non-neutralizing antibody WIS2-11 as a solid-phase, has a sensitivity of two pg/well with coefficients of variation of 3.6-5.8% (within assay) and 5.5-9.5% (between assay). The other assay, employing neutralizing antibody WIS5-85 as a solid-phase, has a sensitivity of four pg/well with coefficients of variation of 2.7-7.2% (within assay) and 9.2-11.2% (between assay). There was a discrepancy between cICAM-1 levels of human plasma determined by these two assays. All samples showed 2- to 5-times higher levels in the assay using WIS2-11 than in that using WIS5-85. The result from the gel electrophoresis employing Western blotting suggests that ICAM-1 circulates in at least two molecular forms with molecular masses of about 85 and 130 kDa and with different reactivities to WIS2-11 and WIS5-85.

Animals↗
PubMed1994

Expression and characterization of a chimeric bispecific antibody against fibrin and against urokinase-type plasminogen activator.

We have produced a chimeric bispecific antibody that has dual specificity of human fibrin and urokinase-type plasminogen activator (u-PA). Complementary DNAs for variable regions of both anti-fibrin and anti-u-PA antibodies were cloned from two murine hybridomas secreting respective antibodies using polymerase chain reaction (PCR) techniques, and joined to cDNAs for human constant regions to form chimeric antibody genes. Both of two expression vectors for chimeric anti-fibrin and chimeric anti-u-PA antibodies were sequentially introduced into Chinese hamster ovary cells, and stable transfectants secreting the chimeric bispecific antibody were obtained. The highest producer transfectant (SULF/C2-30) secreted high level (about 40 micrograms ml-1) of total chimeric IgG and about 2% of the IgG had the bispecific activity of binding with both antigens. The chimeric bispecific antibody was purified by a combination of affinity chromatographies employing antigen-coupled columns and hydroxyapatite high-performance liquid chromatography. The purified chimeric bispecific antibody significantly enhanced the thrombolytic potency of single chain u-PA in an in vitro clot lysis assay as well as the original murine bispecific antibody.

Amino Acid Sequence↗
PubMed1994

Enhancement of the anti-tumor activity of recombinant interleukin-2 (rIL-2) by immunocomplexing with an F(ab')2 fragment of murine monoclonal antibody against rIL-2.

We have investigated the biological properties of an immune complex composed of recombinant interleukin-2 (rIL-2) and an F(ab')2 fragment of a monoclonal antibody against rIL-2 in mice for the induction of killer cells and anti-tumor activity, as well as the pharmacokinetic properties of the immune complex injected subcutaneously into mice. The immune complex demonstrated sustained serum rIL-2 levels, with a 2.4-times longer "mean-residence-time" than free rIL-2. A more significant portion of rIL-2 was detected in lymph nodes after the subcutaneous injection of the immune complex than with rIL-2 alone. Splenic lymphocytes from mice given the immune complex showed higher killer cell activity against YAC-1 and P815 cells than those from mice given rIL-2 alone. The immune complex also exerted a more significant anti-tumor effect in a dose-dependent manner in Meth-A fibrosarcoma-bearing mice than dit rIL-2 alone.

Animals↗