Biomedical subjects
Publications and source records attributed to K Endo.
Explore the source record for details and available documents.
Antitumor activity of a new platinum complex, (R)-(-)-2-aminomethylpyrrolidine (1, 1-cyclobutanedicarboxylato) platinum (II) (DWA 2114 R) against cisdiamminedichloroplatinum (II) (CDDP)-resistant tumor was examined in in vitro and in vivo experiments. CDDP-resistant line was established from L 1210 mouse leukemia cells by continuous exposure to CDDP in dose-escalation manner. Six clones were isolated from parental resistant line and one of these clones, clone f, which was found to be highly resistant (30-40 fold) to CDDP, was used in the following experiments. Clone f showed 4-7 fold cross-resistance to DWA 2114 R and 11-19 fold to cisdiammine-1, 1-cyclobutanedicarboxylatoplatinum (II) (CBDCA) in in vitro growth inhibition assay. DWA 2114 R showed the most effective antitumor activity against mice transplanted with the resistant cells in the increase of life span (ILS%). About 100% of ILS and cured mice were observed in the treatment with DWA 2114 R. On the other hand, CDDP or CBDCA showed a little increase in the survival time (less than 40% of ILS) and all mice died. These results suggest that DWA 2114 R seemed to be more effective against CDDP-resistant tumors clinically than CDDP and CBDCA.
In order to find lung cancer-specific markers, monoclonal antibody 15 (MAb15) was produced against a variant-type cell of small cell lung carcinoma. Its gp85/45 antigens were demonstrated in 70% of lung cancers, and particularly in the proliferating zone of cancer cell nests, but they are scarcely detected in noncancerous tissues. Immunoelectron microscopy revealed that gp85/45 antigens were expressed alternatively on the cell membrane of living cancer cells according to their biological states. MAb15 added to the culture medium inhibited the proliferation of lung cancer cells, depending on its concentration, but cell death rate did not increase. The growth inhibition by MAb15 was reevaluated by a colonogenic assay. On DNA histogram, MAb15 decreased the number of DNA-synthesizing cells in the S phase with an elevation of the G1 peak, indicating a G1-S boundary block in the cell cycle. gp85/45 detected by this lung cancer-associated monoclonal antibody could be a functional membrane unit, such as a growth factor receptor, which is related to the cell proliferation of lung cancer. The growth inhibition by MAb15 may be caused by the blocking of a growth factor receptor which is specific to lung cancer.
The effect of tumor mass and antigenic nature on the biodistribution of 111In- and 125I-labeled monoclonal antibodies (MoAbs) was studied using F(ab')2 fragments of three representative anti-tumor MoAbs and SW1116 human colorectal carcinoma grown in nude mice. The 19-9, F33-104 anti-CEA, and 17-1A MoAbs showed specific binding to SW1116 cells. The former two MoAbs recognize circulating CA 19-9 with molecular weights of more than 5,000,000 and CEA of Mr 170,000-180,000, respectively, whereas 17-1A reacts with a nonshedding antigen. Both percentage injected dose per gram tumor and tumor-to-blood ratios were inversely proportional to the tumor mass in nude mice administered 111In- and 125I-labeled 19-9, but liver uptake increased as tumor size increased. Analysis of serum samples and tumor homogenates demonstrated the presence of a high-molecular-weight species, probably due to the antibody binding to CA 19-9. In the case of 111In-labeled anti-CEA MoAb, tumor uptake also decreased and liver uptake increased with tumor size, but this effect was less obvious than that of 19-9. In contrast, tumor and liver uptake of 125I-labeled anti-CEA MoAb, 111In- and 125I-labeled 17-1A and control antibodies were independent of tumor mass. The absolute tumor uptake and tumor-to-blood ratios of all 125I-labeled antibodies were lower than those of the 111In-labeled ones. And the effect of tumor mass was also weaker with 125I-labeled antibodies, probably due to in vivo dehalogenation. These results indicate that the effect of tumor size on the incorporation of labeled MoAb into tumors is dependent on the antigenic nature to be targeted and/or radionuclides used for labeling and that high concentrations of circulating high molecular weight antigens may limit in vivo use of MoAb conjugates.
In order to know the true biodistribution of anti-tumor monoclonal antibodies, three monoclonal antibodies (OST6, OST7, and OST15) against human osteosarcoma and control antibody were internally labeled with 75Se by incubating [75Se]methionine and hybridoma cells. 75Se-labeled monoclonal antibodies were evaluated both in vitro and in vivo using the human osteogenic sarcoma cell line KT005, and the results were compared with those of 125I- and 111In-labeled antibodies. 75Se-, 125I- and 111In-labeled monoclonal antibodies had identical binding activities to KT005 cells, and the immunoreactivity was in the decreasing order of OST6, OST7, and OST15. On the contrary, in vivo tumor uptake (% injected dose/g) of 75Se- and 125I-labeled antibodies assessed using nude mice bearing human osteosarcoma KT005 was in the order of OST7, OST6, and OST15. In the case of 111In, the order was OST6, OST7, and OST15. High liver uptake was similarly seen with 75Se- and 111In-labeled antibodies, whereas 125I-labeled antibodies showed the lowest tumor and liver uptake. These data indicate that tumor targeting of antibody conjugates are not always predictable from cell binding studies due to the difference of blood clearance of labeled antibodies. Furthermore, biodistribution of both 111In- and 125I-labeled antibodies are not identical with internally labeled antibody. Admitting that internally labeled antibody is a "gold standard" of biodistribution of monoclonal antibody, high liver uptake of 111In-radiolabeled antibodies may be inherent to antibodies. Little, if any, increase in tumor-to-normal tissue ratios of antibody conjugates will be expected compared to those of 111In-labeled antibodies if stably coupled conjugates are administered i.v.
We are investigating the antigenic changes on the cell surface of human hepatocytes that distinguish the normal from the transformed phenotype using monoclonal antibodies. In vivo expression of antigens has been directly assessed by in situ radioimmunohistology. This technique allows one to determine the distribution and density of antigen expression at the individual cellular level on fresh hepatoma and adjacent uninvolved liver tissue. We have found two antigens recognized by monoclonal antibodies XF-8 and AF-20 that are uniformly present on 15/15 hepatocellular carcinomas tested thus far. Most if not all tumor cells highly express these antigens. Such antigens were not evident on adjacent normal liver and the XF-8 epitope was not found on other normal human tissues. AF-20 antigen distribution revealed low-level expression on a subpopulation of cells in the zona glomerulosa of the adrenal gland and on crypt cells of the small intestinal tract. We have studied the capability of radiolabeled XF-8 and AF-20 monoclonal antibodies when administered either alone or in combination to localize a hepatitis B virus-related hepatocellular carcinoma cell line (FOCUS) grown as subcutaneous tumors in nude mice. Biodistribution experiments demonstrated an excellent localization to tumor of 15 to 22% of the injected dose of 125I-labeled antibodies. Indeed, it was possible to enhance the delivery of 125I to the tumor cell surface by the use of XF-8 and AF-20 in combination. Nuclear imaging studies showed sharp visualization of tumor and demonstrate that these monoclonal antibodies have sufficient specificity and sensitivity to be strongly considered as immunotargeting agents.
Color images of single-photon emission computed tomography (SPECT) using technetium-99m(V) dimercaptosuccinic acid (99mTc(V)-DMS) were demonstrated in a patient with lung metastases from osteosarcoma. SPECT image using 99mTc(V)-DMS could be useful for the detection of lung metastasis from osteosarcoma.
Gastric non-Hodgkin lymphoma was unexpectedly detected by gallium-67 scanning in initial staging of the lesions. Single photon emission computed tomography was very useful in determining the accumulation site and indicating further appropriate examinations.
[3H]Methyl group incorporation and histamine secretion in rat mast cells induced by anti-IgE and con A were strongly inhibited by trans-4-guanidinomethylcyclohexanecarboxylic acid 4-tert-butylphenyl ester (GMCHA-OPhBut), a strong and specific inhibitor for pH 7 tryptase (Muramatsu et al. (1988) Biol. Chem. Hoppe-Seyler 369, 617-625) which is present in rat mast cells. The IC50s for these events were of the order of 10(-6) M. Addition of GMCHA-OPhBut after the maximal increase in [3H]methyl group incorporation in rat mast cells activated by con A and anti-IgE induced rapid reduction of the methylated phospholipid, and the later histamine release was strongly suppressed. Mast cells were prepared with Mg2+-free Tyrode-HEPES solution, and challenged with anti-IgE with or without Mg2+. With Mg2+, [3H]methyl group incorporation was enhanced, and histamine was secreted time-dependently. Without Mg2+, [3H]methyl group incorporation fell to one-third, whereas histamine secretion was not affected. These results were incompatible with the above results. From these results it was strongly suggested that a trypsin-like protease, probably pH 7 tryptase, is involved not only in the early events, such as activation of phosphatidylethanolamine methyltransferase I and/or II, but also in the late events such as histamine release, and phospholipid methylation is not associated with histamine secretion.
The effects of brown rice, containing fourfold as much dietary fiber as polished rice, on the human fecal microflora were determined. Significantly increased numbers of Bifidobacterium adolescentis and Enterococcus faecalis were observed during the brown rice intake, whereas the total counts and the numbers of bacteroides, Eubacterium aerofaciens, and Escherichia coli during the intake were lower than those before and after the intake. Lower numbers of clostridia and low incidences of Clostridium paraputrificum and C. perfringens were observed during the brown rice intake.
The Fecal microflora of 15 healthy elderly persons with a median age of 84 years in a rural area whose inhabitants tend to be long-lived (Yuzurihara-area, Uenohara, Yamanashi Prefecture) was compared with the microflora of individuals with a median age of 68 years in an urban area (Tokyo). The diet of the elderly persons in the Yuzurihara area is characterized by a high intake of dietary fiber. Total numbers of anaerobic bacteria were significantly smaller in the elderly persons in the Yuzurihara area than those in the Tokyo area. A significantly large number of bifidobacteria, but not of lecithinase-negative clostridia, was observed in the elderly persons in the Yuzurihara area. Large numbers and high incidences of bacilli and lecithinase-positive clostridia (mainly Clostridium perfringens) were found in the elderly persons in the Tokyo area. Twenty-five genera and over 81 species were isolated from the elderly persons in the Yuzurihara area, and 25 genera and over 92 species were isolated from the elderly persons in the Tokyo area. Furthermore, significantly larger numbers of Bifidobacterium adolescentis and Fusobacterium mortiferum strains were found in the Yuzurihara group, but significant reductions in the Bacteroides buccae-oris group, B. thetaiotaomicron, Bacteroides spp., C. coccoides, C. paraputrificum, and Clostridium spp. were observed in the same group. A significantly higher isolation rate of Bacillus subtilis was observed in the elderly persons in the Tokyo area. The difference in the fecal microflora between elderly persons in Yuzurihara and those in the Tokyo area might be due to a difference in the intake of dietary fiber.
Antigen and concanavalin A (Con A) induced an increase in cAMP and histamine release from rat peritoneal mast cells. In a dose-dependent manner, the compound, NCO-650, significantly inhibited both the initial and secondary increases in cAMP stimulated by antigen, anti-IgE and Con A in rat peritoneal mast cells. IC50 values of NCO-650 for cAMP increase stimulated by antigen, anti-IgE and Con A were 3.8, 3.4 and 2.8 microM, respectively.
The myocardial uptake of 125I- and 131I-antimyosin monoclonal antibody Fab in experimental myocarditis in BALB/c mice induced by encephalomyocarditis virus was studied. The biodistribution of 125I-antimyosin demonstrated that the highest ratio of radioactivity appears in the heart of infected mice on day 14 (the ratio of percent dose per gram for the organ to percent dose per milliliter for blood; 9.75 +/- 2.79 vs. 1.27 +/- 0.78 at 24 hours in inoculated mice vs. control mice). There was no statistically significant difference between the mean activity ratios of tissues other than the heart in control and inoculated mice. The uptake ratio for the heart increased significantly 3 days after virus inoculation and reached a maximum on day 14 when myocardial lesions were most extensive and prominent. The uptake ratio decreased significantly, but it still remained high compared with controls on day 28 when cellular infiltration had decreased and fibrosis was evident. The scintigraphic images obtained with 131I-antimyosin monoclonal antibody clearly demonstrated that visualization of the heart in experimental myocarditis was possible 24 hours after administration of radiotracer, and localized activity was still observed in the 48-hour image. We conclude that antimyosin monoclonal antibodies localize selectively in the heart from the acute to subacute stage of viral myocarditis. These findings indicate that antimyosin scintigraphy is a reliable noninvasive method for the evaluation of patients suspected of having myocarditis.
A practical preparation of various 2,3-dihydro-5H-oxazolo[3,2-a]thieno[3,2-d]-, [3,4-d]-, and [2,3-d]pyrimidin-5-one derivatives was developed starting from the corresponding aminothiopheneesters in two steps, and their chloro-substituted derivatives were prepared. These compounds were evaluated for gastric antisecretory activity in pylorus-ligated rats, compared to the anti-ulcer standard, cimetidine, and their structure-activity relationships are discussed.
Thiazolo[3,2-a]thieno[3,2-d]-, [3,4-d]- and [2,3-d]pyrimidin-5-one derivatives (6, 11 and 16), and polymethylene condensed thieno[3,2-d]-, [3,4-d]- and [2,3-d]pyrimidin-5-one derivatives (19-21), in which the oxygen atom of the oxazolidine moiety in 3 was replaced by a sulfur atom or methylene groups, were synthesized and evaluated for gastric antisecretory activity in pylorus-ligated rats. The structure-activity relationships of these compounds are discussed.
Anti-IgE, con A or antigen caused an increase in the intracellular calcium concentration, [Ca2+]i, of mast cells. The increase occurred in two stages: a rapid initial rise caused by Ca-mobilization from intracellular Ca-stores and a second sustained rise caused by an influx of extracellular calcium (White, J.R., Pluznik, D.V., Ishizaka, K. & Ishizaka, T. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 8193-8197). The rapid initial rise was followed by a release of histamine, which seemed to coincide with the second rise. A23187 and compound 48/80 induced a rapid initial rise in [Ca2+]i, followed by a gradual decrease in [Ca2+]i, GMCHA-OPhBut, a specific pH 7 tryptase inhibitor (Muramatu, M., Ito, T., Takei, M. & Endo, K. (1988) Biol. Chem. Hoppe-Seyler 369, 617-625), strongly inhibited both the initial and second rises of [Ca2+]i, as well as histamine release by these secretagogues, and its effects on the initial rise were closely correlated with those on histamine release. Addition of GMCHA-OPhBut immediately after the initial rise strongly inhibited the second rise, thereby decreasing the final [Ca2+]i. These results strongly suggested a possible involvement of pH 7 tryptase, not only in Ca-mobilization leading to the initial rise in [Ca2+]i, but also in the second rise. Trapping of extracellular calcium by 3mM EGTA decreased both the initial rise in [Ca2+]i and histamine secretion induced by anti-IgE or con A; the magnitude of this effect depended on the time between induction and EGTA addition. Histamine release was closely correlated with the initial rise in [Ca2+]i. Similar results were obtained with A23187, but even 5 min after the addition of EGTA an initial rise of [Ca2+]i could still be induced, and histamine (30% of total histamine) was still released. However, A23187 did not induce a rise in [Ca2+]i in mast cells which had been exhaustively washed with Tyrode/Hepes solution containing 3mM EGTA, followed by suspension in the same solution. Even at 20 min after depletion of the extracellular calcium, compound 48/80 still caused an initial rise in [Ca2+]i to above half the maximal value, and histamine secretion was even less affected. The above results indicated that the initial rise in [Ca2+]i, due to Ca-mobilization, correlates with the histamine release promoted by the secretagogues described. On the other hand, isoproterenol strongly induced histamine secretion with no change of [Ca2+]i, while EGTA treatment prior to isoproterenol stimulation had no effect on histamine release, indicating a different secretion mechanism.
Explore the source record for details and available documents.
With the cleaned metal surface without passive film or an oxide layer, chromium, cobalt, and iron show excellent bonding strength, indicating values similar to 18-8 stainless steel. Therefore the existence of a passive film and oxide layer at the interface metal/resin is not essential for metal-resin bonding. The adhesive ability decreases in the order: Cr congruent to Co congruent to Fe greater than Cu greater than Ag greater than Au congruent to Ni greater than Pt greater than Pd.