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Biomedical subjects

H Takemoto

Publications and source records attributed to H Takemoto.

At least 37 records · Page 2Linked to original sources
PubMed1994

Anti-human IgE monoclonal antibodies recognizing epitopes related to the binding sites of high and low affinity IgE receptors.

Anti-human IgE monoclonal antibodies (mAbs) were produced and eight clones recognizing epitopes on native IgE were selected. Epitopes were mapped by a competitive inhibition enzyme-linked immunosorbent assay, Western blotting and a multi-pin peptide technology. Four sites (one each in the C epsilon 1, C epsilon 2, C epsilon 2/C epsilon 3 junction and C epsilon 3) were recognized by the mAbs. The relationship between the four epitopes and the binding sites of high and low affinity IgE receptors (Fc epsilon RI and Fc epsilon RII, respectively) was studied using a monovalent Fab fragment of each mAb as a binding inhibitor. The IgE-Fc epsilon RII binding was clearly inhibited by the mAb recognizing the C epsilon 2/C epsilon 3 junction, suggesting that Fc epsilon RII binds to a rather limited area around the C epsilon 2/C epsilon 3 junction. The IgE-Fc epsilon RI binding, on the other hand, was scarcely inhibited by any single mAb. However, the binding was inhibited when the epitope in C epsilon 2 was blocked simultaneously with that at the C epsilon 2/C epsilon 3 junction or with that in C epsilon 3, indicating that these three distinct epitopes are related to the Fc epsilon RI binding sites. When these three epitopes were shown in the stereograph of human IgE, the Fc epsilon RI binding area was spread largely on the groove side between C epsilon 2 and C epsilon 3 domains. These results suggest that Fc epsilon RI acquires the high affinity through multiple bindings.

Amino Acid Sequence↗
PubMed1992

Lymphangioma in the small intestine: report of a case and review of the Japanese literature.

We report herein a rare case of a 53 year old man with a benign lymphangioma of the small intestine. He presented with a complete obstruction of the small intestine and radiological examination revealed a small intestinal tumor. A long intestinal tube was passed, the intestinograms from which detected a submucosal tumor of the small intestine. Partial resection of the small intestine was thus performed and the tumor was found to be located mainly in the submucosa. The final pathological diagnosis was made as cavernous lymphangioma. This case is presented with a description of the roentgen appearance, followed by a review of the Japanese literature.

Adult↗
PubMed1992

Heavy chain binding protein (BiP/GRP78) and endoplasmin are exported from the endoplasmic reticulum in rat exocrine pancreatic cells, similar to protein disulfide-isomerase.

Previously we found that in rat exocrine pancreatic cells, protein disulfide-isomerase (PDI), one of the major resident proteins in the lumen of the endoplasmic reticulum (ER) of many cells, is localized not only in the ER but also in the Golgi apparatus, secretory granules, plasma membranes, and even in the glandular lumens, despite possessing the ER retention signal KDEL (Lys-Asp-Glu-Leu) at the carboxyl terminus. In this report, we examined whether other ER luminal proteins bearing the KDEL signal at their C-termini, such as BiP/GRP78 and endoplasmin/GRP94 are also exported from the ER. We prepared two kinds of affinity-purified polyclonal antibodies; one against a synthetic peptide with 12 amino acids which is identical to the carboxyl terminus of BiP and another against purified endoplasmin. Immunoblot analysis using these two antibodies showed that BiP and endoplasmin exist in both the plasma membrane and the microsomal fractions, similar to the intracellular distribution of PDI in rat exocrine pancreas. The ratios of the amount of the three proteins in the two fractions, however, were variable, suggesting that the KDEL-bearing proteins such as PDI, BiP, and endoplasmin are exported from the ER with different efficiencies. Postembedding protein A-immunogold electron microscopy revealed that endoplasmin was exported from the ER and secreted to the extracellular space. The secretion of PDI in rat pancreatic lobules was inhibited by Brefeldin A (BFA) and by guanidino acid esters (FOY-305), which are known to be the inhibitors of the intracellular transport. Taken together with the previous immunogold electron microscopic analyses by Akagi et al. (1988), it is strongly suggested that in rat exocrine pancreatic cells PDI and the other KDEL-bearing proteins found in the extracellular space were not artificially released by cell damage during incubation but were secreted via the normal secretory pathway.

Amino Acid Sequence↗
PubMed1990

Protein disulfide-isomerase in rat exocrine pancreatic cells is exported from the endoplasmic reticulum despite possessing the retention signal.

Recently we found by immunogold electron microscopy that protein disulfide-isomerase (PDI), a major resident protein in the lumen of the endoplasmic reticulum (ER) of many cells, is exceptionally localized in rat exocrine pancreatic cells not only in the ER but also in plasma membranes and other organelles along secretory pathway (Akagi, S., Yamamoto, A., Yoshimori, T., Masaki, R., Ogawa, R., and Tashiro, Y. (1988) J. Histochem. Cytochem. 36, 1069-1074). These observations suggest that another type of PDI, e.g. one with a defective ER retention signal, might exist and be transported in the exocrine pancreatic cells. We therefore compared biochemical and immunochemical properties of the transported PDI with the authentic ER resident PDI. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, peptide mapping, urea-polyacrylamide gel electrophoresis, and isoelectric focusing showed that the former was indistinguishable from the latter. We prepared a polyclonal antibody against the synthetic hexapeptide, which corresponds to the carboxyl terminus of PDI containing the putative ER retention signal "KDEL." The epitopes of this antibody (anti-KDEL antibody) were located within the KDEL sequence. Anti-KDEL antibody reacted with PDI in both the plasma membranes and the ER of rat pancreatic cells in immunoblot analysis as well as in immunogold electron microscopy. These results suggest that PDI exported from the ER to the plasma membranes in rat exocrine pancreatic cells possesses the KDEL sequence.

Amino Acid Isomerases↗
PubMed1990

[A case report of very huge dermatofibrosarcoma protuberans].

A 63-year-old male with dermatofibrosarcoma protuberans of the right hip is presented. The patient noticed a small nontender mass 40 years ago and then the tumor enlarged gradually. The patient was very emaciated and needed to receive blood transfusions. The massive multinodular tumor was pedunculated and on it's surface, there were areas of hemorrhage and secondary infection. The operative specimen weighted 2270 g and measured up to 25 by 20 by 10 cm. To our knowledge, this case represents the largest primary tumor of a dermatofibrosarcoma protuberans in review of English literature.

Fibrosarcoma↗
PubMed1989

Murine interleukin-2 receptor subunits differentially detected with anti-interleukin-2 monoclonal antibodies.

Cross-linking of radioiodinated interleukin-2 to murine CTLL-2 cells enabled detection of 70 kDa, 85 kDa and 105 kDa complexes of IL-2 and its binding proteins under the high-affinity binding condition. A series of anti-interleukin-2 monoclonal antibodies (L15, L20, L23, L34, and L61) were tested for their activity to immunoprecipitate these cross-linked complexes. L61, which had strong neutralizing activity, precipitated only the 70 kDa complex. L15, L20, and L34, which also had neutralizing activity, precipitated not only the 70 kDa complex but also the 85 kDa complex. L23, which had practically no neutralizing activity, precipitated the 105 kDa complex as well as the 85 kDa complex. These results suggest that there are at least three distinct receptor binding sites for each receptor subunit on the interleukin-2 molecule, which are discernible by these monoclonal antibodies and that the 105 kDa complex may play a significant role in the formation of the high-affinity receptor complex and the signal transduction.

Animals↗
PubMed1989

Granulation at the porta hepatis following hepatic portoenterostomy for biliary atresia: the healing of experimental hepatoenterostomy.

After hepatic portoenterostomy for biliary atresia, granulation that formed at the porta hepatis caused biliary obstruction in seven out of 27 patients (26%). Six of the seven developed the complication during the first 6 weeks after surgery. The mortality rate was 29% (2/7). Among the same group, the incidence and mortality rate of ascending cholangitis was 19% (5/27) and 20% (1/5), respectively. The features characteristic of biliary obstruction caused by granulation, as compared with those of ascending cholangitis, were the absence of signs of infection and the lack of response to medical treatment. Quantitative analysis of the healing process of an experimental hepatoenterostomy in the rat showed that the mean thickness of the granulation formed at the anastomotic site (area, 5 x 20 mm) decreased almost constantly--from 1.49 mm on day 7 to 0.64 mm on day 42. Mucosa covered 20% of the granulation on day 7, 55% on day 14, 63% on day 21, 76% on day 28, and 92% on day 42. The increase in coverage was greatest during the second postoperative week. The results suggested that the healing of the hepatoenteostomy should be almost complete within 6 weeks. The operative method and postoperative management to prevent excessive granulation should be chosen so as to decrease the incidence of postoperative biliary obstruction.

Animals↗
PubMed1988

Monoclonal antibodies which differentiate high- and low-affinity binding sites of interleukin-2.

Five monoclonal antibodies (L15, L20, L23, L34, and L61) against human recombinant interleukin-2 were tested for their effects on the interleukin-2 bioactivity and binding. Four of these monoclonal antibodies, L15, L20, L34, and L61, which had neutralizing activity, completely blocked interleukin-2 binding to the high-affinity receptor. On the other hand, L23, which had a very weak neutralizing activity, blocked interleukin-2 binding to the low-affinity receptor. These results suggest that there are at least two distinct binding sites on the interleukin-2 molecule; those for the high-affinity receptor and those for the low-affinity receptor. These monoclonal antibodies should be useful tools in the study of the interaction between interleukin-2 and interleukin-2 receptor.

Animals↗
PubMed1988

Icteric flare-up in patients with biliary atresia after hepatic portoenterostomy.

The relapse of icterus may be a sign of serious postoperative complication after hepatic portoenterostomy for biliary atresia. To analyse the cause of such icteric flare-up, a retrospective study was made on 27 patients. A total of 38 episodes of icteric flare-up occurred in 19 patients. An accompanying disease, which had not directly involved the biliary tract, was assumed to be the cause in 11 episodes (29%). Fourteen episodes (37%) were due to biliary tract infection caused by the cyst formed at the porta hepatis (5 episodes) or so-called ascending cholangitis (9 episodes). The other 13 episodes (34%) were free from both accompanying disease and signs of biliary infection. Among them, the cause of icteric flare-up was the cyst at the porta hepatis in one episode, scar tissue formation at the porta hepatis in 9 episodes and undetermined in 3 episodes.

Biliary Atresia↗
PubMed1986

Structure of a sugar chain of a protease inhibitor isolated from barbados pride (Caesalpinia pulcherrima Sw.) seeds.

An asparagine-linked sugar chain of a protease inhibitor from barbados pride (Caesalpinia pulcherrima Sw.) was liberated by hydrazinolysis. After N-acetylation, the reducing end residue of this carbohydrate unit was coupled with 2-aminopyridine and the pyridylamino (PA-) derivative was purified by gel-filtration and reversed-phase HPLC. The structure of the resulting PA-sugar chain was determined mainly by stepwise exoglycosidase digestions and 500 MHz 1H-NMR spectroscopy and proved to be as follows: (formula; see text).

Carbohydrate Conformation↗
PubMed1986

The structure of sugar chains of Japanese quail ovomucoid. The occurrence of oligosaccharides not expected from the classical biosynthetic pathway for N-glycans; a method for the assessment of the structure of glycans present in picomolar amounts.

While the structure of the major oligosaccharide of Japanese quail ovomucoid was reported earlier (Hase, S. et al. (1982) J. Biochem. 91, 735-737), the structures of the minor oligosaccharide units were investigated for the first time in the present studies. For this purpose, the glycans of the protein were liberated from the polypeptide chain by hydrazinolysis. After N-acetylation, the reducing ends of the oligosaccharides obtained were coupled with 2-aminopyridine, and then the resulting fluorescent derivatives were purified by Bio-Gel P-2 column chromatography and reversed-phase HPLC. The chemical structures of two minor oligosaccharide units were determined with the aid of exoglycosidases, and by methylation analysis and Smith degradation. The results demonstrated that the ovomucoid contains the following two monoantennary glycans: Man alpha 1-6(Gal beta 1-4GlcNAc beta 1-2Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4GlcNAc and Gal beta 1-4GlcNAc beta 1-2Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4GlcNAc. The latter structure was not predicted by the classical metabolic pathway for the N-glycans to be formed. The structures of three additional minor heterosaccharides were deduced from their elution positions on HPLC together with the results of determination of their molecular sizes and the HPLC elution positions of their enzymatic degradation products. It is noteworthy that for the latter procedure for the estimation of the structures of oligosaccharides only minute quantities of glycans (several hundreds pmol) are required.

Amino Acids↗
PubMed1985

Microquantitative analysis of neutral and amino sugars as fluorescent pyridylamino derivatives by high-performance liquid chromatography.

A method for the quantitation of picomole amounts of neutral and amino sugars in glycoconjugates was developed. Glycoconjugates were hydrolyzed with a mixture of equal amounts of 4 M trifluoroacetic acid and 4 M hydrochloric acid, and the free amino groups were acetylated. Sugars were coupled with 2-aminopyridine. After the excess reagents were removed by gel-permeation high-performance liquid chromatography, the fluorescent pyridylamino derivatives of sugars were separated and quantified by high-performance liquid chromatography on a reversed-phase column. This method allowed the determination of 0.01-10 nmol of sugars. About 100 pmol of several glycoconjugates were analyzed by the present method, with satisfactory results.

Amino Sugars↗
PubMed1984

[Experimental and clinical studies on the intestinal anastomosis and reconstruction of the alimentary tract].

Healing process of anastomosis and its procedure were studied in following points: Four-interrupted sutures anastomosis in the Wistar rats revealed recanalization without leakage in 64 out of 69. Lymphangial recanalization through the anastomosis was completed within 21 days after operation by Gambee' layer-to-layer anastomosis. While 8 weeks were required by everted or inverted anastomosis. Serosal surface of invaginated intestinal segment of which length corresponded to x1-x2 luminal diameter in the telescoping anastomosis was covered within 8 weeks by the proliferated mucosae of the both proximal and distal segments. Telescoping anastomosis was found to be useful to make an intestinal valve which worked just the same as ileocoecal junction. IVH and elementary diet were effective on the healing of anastomosis. According to the above mentioned findings, following operative procedures were recommended: Esophago-jejunal conduit duodenostomy following total gastrectomy. Choledocho-jejunal conduit duodenostomy with the intestinal valve as bile duct reconstruction. Construction of the intestinal valve and an artificial sphincter using rectus abdominis muscle fibers for ileostomy or short bowel syndrome. Endorectal pull-through operation for anterior-resection of the rectum as well as for radical treatment of Hirschsprung' disease.

Animals↗
PubMed1981

Focal-spot separation in stereoscopic magnification radiography.

Mathematical formulas relating focal-spot separation to various geometric factors in magnification radiography are presented. Focal-spot separation is closely related to the magnification factor, focal-spot/film distance, viewing distance, and object size. When the viewing distance is equal to the focal-spot/film distance, separation is inversely proportional to magnification.

Angiography↗