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Biomedical subjects

K Imai

Publications and source records attributed to K Imai.

At least 991 records · Page 55Linked to original sources
PubMed1991

New assay to detect shedding antigen with use of anti-idiotypic monoclonal antibodies.

Anti-idiotypic (Anti-Id) monoclonal antibodies (MoAbs) against anti-carcinoembryonic antigen (CEA) monoclonal antibody 5B3 (IgG1) were prepared and characterized. Five anti-Id MoAbs recognized the private idiotype of MoAb 5B3. Idiotype mapping suggested that MoAb 5B3 had at least three distinct idiotopes at its antigen combining site. Utilizing the inhibition of idiotype-anti-idiotype interaction with use of anti-Id MoAb T4-305 or T4-212, an immunoassay to detect shedding CEA was established. The results of this inhibition assay correlated with those of double determinant immunoassay and inhibition percentages linearly increased in a CEA concentration-dependent manner. Since it requires only one epitope of a given antigen molecule, this assay could be widely used for detection of shedding antigens, including tumor-associated antigens.

Animals↗
PubMed1991

Co-expression of X-hapten-like antigen and antigen YH206 on mucin molecules.

The asialocarbohydrate antigen YH206 is expressed on adenocarcinoma-associated mucin molecules which lack epitopes of CA19-9 and DU-PAN-2. To further characterize this molecule, the monoclonal antibody BM2 against the affinity-purified antigen YH206 was established. It was demonstrated by an inhibition test that antigen BM2 was an X-hapten-like structure, one of the representative oncodevelopmental antigens. Although the sensitivity of antigen BM2 in sera of stomach and pancreas cancer patients did not appear to be superior to that of antigen YH206, both antigens were complementary to each other resulting in the improvement of sensitivity. Interestingly, double-determinant enzyme immunoassays showed that antigen BM2 and YH206, both having a cryptic nature for neuraminidase, were co-expressed on the same mucin molecule in sera of patients with stomach cancer or liver cirrhosis. These data suggest that mucin molecules in serum might be classified into several groups based on the distribution of tumor-associated epitopes.

Adenocarcinoma↗
PubMed1991

Lymphocytes stimulate progesterone production by cultured human granulosa luteal cells.

After follicular rupture, massive invasion of blood vessels with neovascularization of the developing corpus luteum takes place, providing many chances for direct contact of luteal cells with resident and migrating immune cells. We studied the effects of peripheral blood lymphocytes on progesterone production by human granulosa luteal cells isolated from women undergoing in vitro fertilization. During 6 days of culture, progesterone production by granulosa luteal cells was significantly increased when they were cultured together with autologous or allogenic peripheral blood lymphocytes. This stimulatory effect was also observed on the addition of medium conditioned with peripheral blood lymphocytes and was synergistic with gonadotropin stimulation. The activity was present in the fraction retained by ultrafiltration with a 30,000 molecular weight cutoff filter and was preserved after heating at 56 degrees C for 30 minutes but disappeared after heating at 70 degrees C for 15 minutes. These findings suggest that lymphocytes infiltrating the corpus luteum during early luteinization can stimulate the function of human granulosa luteal cells through the action of some protein-like humoral factor(s) of higher molecular weight than that of previously identified lymphokines and indicate a possible paracrinologic regulatory role for lymphocytes in ovarian function.

Cells, Cultured↗
PubMed1991

A novel enzyme immunoassay for serodiagnosis of Helicobacter pylori infection.

Helicobacter pylori has recently been implicated as an etiologic agent of gastroduodenal disorders. Comparing the antibody to H. pylori in the sera of patients with that of normal controls by Western blot analysis, a unique antibody was detected in the sera of patients, which reacted with the 25-kilodalton antigen of H. pylori. On the other hand, monoclonal antibody CP3 prepared in the authors' laboratory also recognized the 25-kilodalton antigen of H. pylori. Whether the serum antibody of the patient recognized the CP3 antigen purified by monoclonal antibody CP3 was then examined. Western blot analysis showed that the patient's serum reacted strongly with the affinity-purified CP3 antigen. Using monoclonal antibody CP3, an enzyme-linked immunosorbent assay to detect CP3 antibody in sera was established. In patients with chronic gastritis and gastric ulcers, the titer of CP3 antibody was significantly higher than in normal controls and correlated with the histological grade of antral gastritis. The detection of CP3 antibody in sera is useful in the diagnosis of chronic gastritis and gastric ulcer associated with H. pylori infection and also in evaluation of the grade of gastritis.

Animals↗
PubMed1991

Characterization of chicken ACTH and alpha-MSH: the primary sequence of chicken ACTH is more similar to Xenopus ACTH than to other avian ACTH.

Adrenocorticotropic (ACTH) and melanocyte stimulating (MSH) hormones have been demonstrated in the same cells in the cephalic half of the pars distalis of the chicken pituitary glands in three ways: (I) immunohistochemistry, (II) radioimmunoassay (RIA) using both anti-human or porcine ACTH and synthetic alpha-MSH antibodies, and (III) isolation and purification, followed by the determination of amino acid compositions of both hormones. The contents of ACTH and alpha-MSH are estimated by RIA to be 1600 and 10 ng/gland, respectively. ACTH missed 1 (des-Phe39-ACTH) or 2 residues (des-Glu38, Phe39-ACTH) from the C-terminal portion was also isolated. The recoveries of these ACTHs are differed from preparation to preparation. The complete amino acid sequence of chicken ACTH (39 residues) has been determined as NH2-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-Gly-Arg-Lys-Arg- Arg- Pro-Ile-Lys-Val-Tyr-Pro-Asn-Gly-Val-Asp-Glu-Glu-Ser-Ala-Glu-Ser-Tyr-Pro- Met-Glu-Phe-OH Strikingly the amino acid sequence of chicken ACTH shows a closer resemblance to that from an amphibian, Xenopus (3 residue substitution) than that from another bird, the ostrich (7 residue substitution) or the turkey (at least 9 residue substitution).

Adrenocorticotropic Hormone↗
PubMed1991

Isolation and characterization of hemorrhagic toxin from the venom of Trimeresurus elegans.

1. Hemorrhagic toxin from the venom of Trimeresurus elegans was purified in a homogeneous form using gel filtration and ion exchange chromatographies. 2. Hemorrhagic toxin possessed hemorrhagic and TAME (tosyl-L-arginine methyl ester) hydrolytic activities. These activities were inhibited when hemorrhagic toxin was incubated with benzamidine or N-bromosuccinimide. 3. Its mol. wt was 28,500 and the isoelectric point was 7.4. 4. This toxin contains ca 1.5 mol Ca per mol of protein.

Amino Acid Sequence↗
PubMed1991

Tumor-targeted chemotherapy with lipid contrast medium and macromolecular anticancer drug (SMANCS) for renal cell carcinoma.

Twenty-five patients with renal cell carcinoma were treated with a lipophilic macromolecular drug, poly(stylene-co-maleic acid)-conjugated neocarzinostatin (SMANCS) dissolved in lipid contrast medium (Lipiodol). The drug was injected by catheterizing the renal artery and another feeding artery in 24 patients, and in the common hepatic artery in 1 patient with metastases to the liver after a radical nephrectomy. The procedure of selective arterial administration of 3-20 mg/mL of SMANCS/Lipiodol was simple to perform and was required once every two to three weeks. Total dose of SMANCS for each patient varied from 3 to 57 mg. Both SMANCS and Lipiodol accumulated more selectively in tumor than in any other tissue and remained in the neovasculature and extracapillary space for a long time. CT pattern of the remaining oil contrast medium in the tumor was characterized by the high-density area localized mainly in the periphery of the tumor around the central necrosis. When hyperviscosity Lipiodol (Lipiodol HV) was used as lipid contrast medium, it remained more persistently in the tumor and disappeared more slowly than Lipiodol. Moreover, the pronounced anticancer effect was recognized when SMANCS/Lipiodol HV was administered compared with only SMANCS/Lipiodol. Severe side effects, such as myelosuppression, unendurable pain, paralytic ileus, etc., were not observed. This targeting chemotherapy may be of great significance for advanced renal cell carcinoma.

Adult↗
PubMed1991

In vivo characteristics of high molecular weight copoly(L-lactide/glycolide) with S-type degradation pattern for application in drug delivery systems.

Amorphous copoly(L-lactide)/glycolide, 70/30 mol%) with weight average molecular weights of 16,900-41,300 were synthesized by ring-opening polymerization in the presence of catalysts using a molecular weight moderator lauryl alcohol. The in vivo degradation profiles of the copolyesters, which were evaluated by implanting them subcutaneously in the back of rats, showed a typical S-type degradation pattern. A luteinizing hormone-releasing hormone agonist (LH-RH agonist), des-Gly10-[Leu6]-LH-RH ethylamide monoacetate, was incorporated into the small cylinders of copoly (L-lactide/glycolide) with a weight average molecular weight of 24,000. The cumulative amount of drug released in vivo from the cylinders showed an S-type profile in analogy with the in vivo degradation pattern. This was demonstrated from data such as serum drug level and pharmacological influence on rat prostates.

Animals↗
PubMed1991

Regulation of lymphocyte blastogenesis and antibody production by soluble factor released by a human B-lymphoblastoid cell line.

Yam 1B, a human B lymphoblastoid cell line, spontaneously produced an immunoregulatory factor, which suppresses blastogenesis and antibody formation by human lymphocytes. The Yam 1B cells, which were derived from the peripheral blood of an adult T-cell leukemia patient, have been established and maintained in our laboratory since 1985. This cell line expressed mature B-cell surface antigens including surface immunoglobulin M (IgM), CD23, and HLA-DR; had cytoplasmic IgM; and secreted small amounts of IgM in the culture supernatants. Yam 1B was positive for Epstein-Barr virus-associated antigen (EBNA) but negative for adult T-cell-associated antigen (ATLA). The serum-free Yam 1B culture supernatants (SN) inhibited the expression of transferrin R, but neither the expression of interleukin 2 (IL-2) R(CD25) nor the production of IL-2 in the lymphocytes stimulated with phytohemagglutin. Yam 1B SN also inhibited DNA synthesis by human T and B lymphocytes and immunoglobulin generation by normal B cells as well as by Epstein-Barr virus-transformed human B lymphoblastoid cell lines. The inhibitory activity of Yam 1B SN was inactivated at 56 degrees C and at pH 10 but was relatively stable at pH 2. It was abrogated by digestion with pronase and was partially stable by digestion with trypsin. Fractions collected from a Sephacryl S-300 gel filtration column (Pharmacia Fine Chemicals, Uppsala, Sweden) were found to have a peak of inhibitory activity of cell proliferation associated with molecules of apparent MWr of 43,000 to 67,000. The inhibitory activity of Yam 1B SN was not blocked by the anti-transforming growth factor beta antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

B-Lymphocytes↗
PubMed1991

Use of 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole as a labelling reagent for peroxyoxalate chemiluminescence detection and its application to the determination of the beta-blocker metoprolol in serum by high-performance liquid chromatography.

Fluorogenic reagents having a benzofurazan moiety, viz., 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F), 7-fluoro-4-nitro-2,1,3-benzoxadiazole and 4-(aminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole, were compared for the sensitive analysis of their derivatives by high-performance liquid chromatography with peroxyoxalate chemiluminescence detection. Of the proline derivatives, DBD-proline was the most sensitive with a detection limit of 2 fmol. The optimum concentrations of bis[4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl] oxalate and H2O2 for the post-column reaction were 0.5 and 75 mmol dm-3 respectively and amino acids and beta-blockers derivatized with DBD-F were detected in the range 0.2-40 fmol (signal-to-noise ratio = 3) using the proposed method. The lower detection limit of metoprolol (a beta-blocker having an isopropylamino group) spiked in serum was 0.8 ng ml-1 using 20 microl of serum (signal-to-noise ratio = 5).

Chromatography, High Pressure Liquid↗
PubMed1991

Monoclonal antibody against murine T cell receptor V alpha 14 cross-reacts with human CD3 epsilon and detects disulfide-linked dimeric form.

A monoclonal antibody against V14+ alpha-chain of murine T cell receptor (TCR) was established by fusing spleen cells from a rat immunized with a soluble chimeric TCR/IgG3 protein containing murine TCR V alpha 14J alpha 281 in place of the VHDHJH of an IgG3. lambda 1, and subjected to screening on a human transfectant (Jurkat variant) expressing the murine V14J281 alpha-chain. The anti-mouse V alpha 14 antibody precipitated TCR alpha beta molecules from Triton X-100-solubilized extracts of 125I-labeled murine thymocytes and spleen cells. Unexpectedly, the antibody showed cross-reactivity to the human CD3 epsilon molecule and detected a disulfide-linked 20 kDa dimeric form of human CD3 epsilon, which is a novel family component of the CD3 complex and is associated closely with the CD3 zeta-zeta homodimer as well as TCR alpha beta or TCR gamma delta.

Animals↗
PubMed1991

Immunohistochemical localization of superoxide dismutase in the human ovary.

To elucidate the physiological function of superoxide dismutase (SOD) in the ovary, we examined the immunohistochemical distribution of CuZn-SOD in the human ovary. We also measured the CuZn-SOD concentration in human follicular fluid by enzyme-linked immunosorbent assay (ELISA). The germinal epithelium and tunica albuginea showed no or weak immunoreactivity. No or weak staining activity was also observed in the non-antral follicle. Once the follicle began to form the antral cavity, theca interna cells began to show intensive immunostaining of SOD, as compared with no staining in the granulosa and theca externa cells. In the gestational corpus luteum, theca and granulosa lutein cells showed intensive and moderate staining activity, respectively. The concentration of CuZn-SOD was 0.222 +/- 0.186 ng/mg protein (mean +/- SD) in the preovulatory follicular fluid. In the present study, the immunohistochemical distribution of SOD was confirmed in the human ovary for the first time. Taking into consideration the fact that SOD catalyses the dismutation reaction of superoxide anion radicals, the present results suggest that theca interna cells play an important role in the protection of the developing oocyte from oxygen radicals by acting as a blood-follicular barrier during follicle maturation.

Adult↗
PubMed1991

Arginine-specific ADP-ribosyltransferase and its acceptor protein p33 in chicken polymorphonuclear cells: co-localization in the cell granules, partial characterization, and in situ mono(ADP-ribosyl)ation.

We have reported the purification and characterization of arginine-specific ADP-ribosyltransferase from hen liver nuclei [Tanigawa, Y. et al. (1984) J. Biol. Chem. 259, 2022-2029] and the DNA-dependent mono(ADP-ribosyl)ation of p33, an acceptor protein in the nuclei [Mishima, K. et al. (1989) Eur. J. Biochem. 179, 267-273]. In the present study, we obtained evidence that among various tissues and cells from chicken, polymorphonuclear cells, so-called heterophils, possess both the ADP-ribosyltransferase and p33 at high levels. Percoll density gradient centrifugation of the postnuclear fraction of the heterophils revealed the co-localization of ADP-ribosyltransferase with p33 in the granule fraction. The enzyme and p33 were purified approximately 219- and 3.77-fold, respectively, from postnuclear pellet fraction to apparent homogeneity. The properties of heterophil ADP-ribosyltransferase and p33 were compared with those of the liver enzyme and p33. The molecular mass of the heterophil enzyme was estimated by SDS-polyacrylamide gel electrophoresis to be 27.5 kDa. The enzyme activity was stimulated by a sulfhydryl agent and inhibited by lysolecithin, NaCl, and inorganic phosphate. The mono(ADP-ribosyl)ation of p33 was markedly enhanced by polyanion, such as DNA, RNA, or poly(L-glutamate). SDS-polyacrylamide gel electrophoretic analysis after limited trypsin proteolysis of p33s, purified from chicken heterophils and liver, showed much the same pattern. Thus, it appears that ADP-ribosyltransferase and p33 present in heterophils are identical to those in the liver, respectively. p33 is considered to be an in situ substrate for ADP-ribosyltransferase, since it was specifically mono(ADP-ribosyl)ated in permeabilized heterophils.(ABSTRACT TRUNCATED AT 250 WORDS)

ADP Ribose Transferases↗
PubMed1991

Correlated expression of mRNAs of carcinoembryonic antigen and nonspecific cross-reacting antigen genes in malignant and nonmalignant tissues of the colon.

Expression of carcinoembryonic antigen (CEA) and nonspecific cross-reacting antigen (NCA) mRNAs were observed in malignant and nonmalignant colon tissues by Northern blot analysis. CEA mRNA was detected together with NCA mRNA in nine cultured cell lines, with the exception of the lung carcinoma A549 cell line, and in 19 colon tissue specimens, including carcinomas, adjacent noninvaded tissues and adenomas. When we compared the intensity of the hybridization signal for CEA or NCA mRNA among adenomas, carcinomas and adjacent noninvaded tissues, NCA mRNA rather than CEA mRNA was highly expressed in carcinomas compared to adjacent nonivaded tissues. When, however, the relation between the intensities of hybridization signals for CEA and NCA mRNAs were evaluated in five colon carcinoma cell lines and 19 colon tissue specimens, a statistically significant correlation was observed (gamma = 0.462, P less than 0.01). These data suggest that NCA may be more useful as a tumor marker for colon carcinoma than CEA at the level of mRNA, and that transcriptions of the CEA and NCA genes might be regulated by some common mechanisms in malignant and nonmalignant tissues of the colon.

Adenoma↗
PubMed1991

Reconstruction of two separated electrical burn ulcers.

In this study, we describe the reconstruction of composite tissue defects in two separated regions (left elbow and right thigh) using only one-sided rectus abdominis myocutaneous flap. We report here the results of our procedure, as it increases the usefulness of the rectus abdominis myocutaneous flap and can be applied to other clinical situations.

Adult↗
PubMed1991

Cytokine regulation of ICAM-1 expression on human renal tubular epithelial cells in vitro.

Regulation of the intercellular adhesion molecule-1 (ICAM-1) expression on human renal tubular epithelial cells in culture (hKEC-1) was investigated. A large proportion of hKEC-1 cells from the primary cultures expressed the ICAM-1 antigen. Supernatants from mixed lymphocyte reaction (MLR) of both specific and third-party combinations augmented the expression of the ICAM-1 antigen, in a dose-dependent manner. A kinetic study revealed maximal augmentation by MLR supernatant on the first day, with a gradual decrease thereafter. Among several recombinant human cytokines tested, i.e., interferon-gamma, tumor necrosis factor-alpha, interleukin 1 alpha and beta, and IL-4, IFN-gamma, TNF-alpha, and IL-1 alpha/beta were shown to augment the expression of ICAM-1. MLR supernatants and IFN-gamma were more effective in augmenting ICAM expression than TNF-alpha and IL-1 alpha/beta. IFN-gamma upregulated ICAM-1 expression in a dose-dependent manner, and maximal augmentation was achieved on the first day. The MLR supernatants were shown to contain IFN-gamma and TNF-alpha, and the activity of the MLR supernatant was partially inhibited by neutralizing antibody against IFN-gamma. These data suggest that cytokines, especially IFN-gamma, TNF-alpha, and IL-1 alpha/beta, released by T cells and antigen-presenting cells upon recognition of alloantigens upregulate ICAM-1 expression on renal tubular epithelial cells. This may result in an increase in the attachment of graft-infiltrating T cells to the renal tubular cells, by the ICAM-1-LFA-1 interaction.

Antigens, CD↗
PubMed1991

Colonization of Helicobacter pylori in the gastric mucosa of Mongolian gerbils.

Helicobacter pylori was orally inoculated into Mongolian gerbils. The organisms were able to colonize in the gastro-mucosal layer of the gerbils, especially in those gerbils which had mucosal lesions caused by indomethacin treatment. The pathological changes developed by H. pylori infection were restricted to the stomachs, and only slightly inflammatory cells were observed.

Animals↗