Search PubMed⌕ Search

Biomedical subjects

K Sekiguchi

Publications and source records attributed to K Sekiguchi.

At least 217 records · Page 12Linked to original sources
PubMed1984

[Patterns of recurrence and survival in breast cancer].

Sixty-nine patients have shown recurrence after curative (standard, extended and modified) mastectomy from 1969 to 1978 in our department. Recurrence patterns and prognostic factors were analyzed using life-table and log-rank methods. Thirty-four patients (49%) developed their first recurrence within two years after surgery and died within two years after that. This period seemed to be high-risk after surgery and first recurrence. The disease-free interval and survival after first recurrence seemed to be shorter with the more advanced presenting Tnm stage. The disease-free and recurrence-to-death intervals of patients with first loco-regional recurrence seemed to be longer than those with first distant metastases.

Adult↗
PubMed1983

Binding of fibronectin and its proteolytic fragments to glycosaminoglycans. Exposure of cryptic glycosaminoglycan-binding domains upon limited proteolysis.

Binding of intact plasma fibronectin and its proteolytic fragments to glycosaminoglycans immobilized on agarose beads was systematically compared at different ionic strengths. In low ionic strength buffer, intact fibronectin bound to heparin and high sulfated heparan sulfate, but not to low sulfated heparan sulfate, dermatan sulfate, chondroitin sulfates A and C, or hyaluronic acid. Fractionation of the thermolysin digest of fibronectin on the glycosaminoglycan-Sepharoses at low ionic strength revealed that three groups of fragments, i.e. Mr = 150,000-140,000, 24,000, and 16,000 (150K-140K, 24K, and 16K) fragments, were capable of binding to glycosaminoglycans with different specificities and affinities. The 150K-140K fragments exhibited the same specificities as intact fibronectin, binding only to heparin and high sulfated heparan sulfate. However, the 24K fragment bound not only to these two glycosaminoglycans but also to low sulfated heparan sulfate and other glycosaminoglycans as well. The 16K fragments were also capable of binding to most glycosaminoglycans with lower affinity than the 24K fragment. These results suggest that the binding sites in the 24K and 16K fragments are cryptic in the intact protein, but are exposed after limited proteolysis. The binding of fibronectin and its fragments to glycosaminoglycans is dependent on the ionic strength. At physiologic ionic strength, only heparin-Sepharose could bind intact fibronectin. Similarly, only heparin-Sepharose could bind the 150K-140K and 24K fragments, but not the 16K fragments, at the same ionic condition. Other glycosaminoglycan-Sepharoses did not retain significant amounts of any of the fibronectin fragments, suggesting that the affinity of plasma fibronectin and its fragments to heparan sulfate and other glycosaminoglycans, except heparin, is not strong enough to achieve stable mono- (or di-) valent binding under physiologic conditions.

Animals↗
PubMed1983

Identification of fibronectin fragments that bind to carboxy-group-modified proteins.

Limited proteolysis of human plasma fibronectin with chymotrypsin, trypsin or thermolysin has been used to localize binding sites responsible for binding [Vuento, Korkolainen & Stenman (1982) Biochem. J. 205, 303-311] of fibronectin to carboxy-group-modified proteins. These bindings sites are different from those mediating binding of fibronectin to gelatin or heparin. They are located close to the C-terminus of the polypeptide chains of fibronectin, and apparently overlap with the C-terminal fibrin binding site.

Binding Sites↗
PubMed1983

Differences in domain structure between pericellular matrix and plasma fibronectins as revealed by domain-specific antibodies combined with limited proteolysis and S-cyanylation: a preliminary note.

Differences in domain structure between human fibronectins obtained from pericellular matrix and plasma have been revealed by limited proteolysis and S-cyanylation, followed by identification of each domain with domain-specific antibodies. Although the overall domain structure is similar between pericellular and plasma fibronectins, the fragments derived from the COOH-terminal region of these fibronectins, which were defined by specific antibodies, exhibited clear differences in their molecular weights and protease susceptibility, suggesting that the structure near the COOH-terminal region is significantly different between these two proteins.

Antibodies↗
PubMed1983

A monoclonal antibody directed to N-acetylneuraminosyl-alpha 2 leads to 6-galactosyl residue in gangliosides and glycoproteins.

A hybridoma cell line producing a monoclonal antibody directed to N-acetylneuraminosyl-alpha 2 leads to 6-galactosyl residue has been established. The antibody is IgG2b and reacts only with lacto-series gangliosides as well as with glycoproteins having an N-acetylneuraminosyl-alpha 2 leads to 6-galactosyl residue, but does not react with gangliosides or glycoproteins having an N-acetylneuraminosyl-alpha 2 leads to 3- or -alpha 2 leads to 4-galactosyl residue. The antibody is useful for detecting the specific carbohydrate chain having this terminal structure by immunostaining of glycolipids separated on thin layer chromatography or glycoproteins separated on gel electrophoresis after blotting on nitrocellulose sheet. A remarkable accumulation of a few gangliosides having this terminal structure has been detected by this monoclonal antibody in some human cancer.

Adenocarcinoma↗
PubMed1983

Agglutinins in the horseshoe crab hemolymph: purification of a potent agglutinin of horse erythrocytes from the hemolymph of Tachypleus tridentatus, the Japanese horseshoe crab.

Agglutinins from Tachypleus (Tachypleus tridentatus, the Japanese horseshoe crab) hemolymph were isolated by affinity chromatography on BSM-coupled Sepharose 4B. The agglutinins showed multiple species and were composed of eight heterogeneous subunits with molecular weights of 45,000, 42,000, 41,000, 39,000, 33,000, 29,000, 27,000, and 22,000 as determined by SDS-polyacrylamide gel electrophoresis. The affinity-isolated agglutinins were fractionated into four groups by gel filtration on a Fractogel TSK (Toyopearl) HW-65 column, and these were designated as Tachypleus tridentatus agglutinin (TTA)-I, -II, -III, and -IV in the order of elution. These agglutinins were demonstrated to be heterogeneous as judged by their specificity towards horse erythrocytes, subunit structures, and immunological properties. TTA-III showed a potent agglutination activity towards horse erythrocytes and was further purified by gel filtration on a Cellulofine GC-700 column. The purified TTA-III is a highly purified (46,000-fold) protein composed of homogeneous subunits (Mr, 42,000) as judged by SDS-polyacrylamide gel electrophoresis and immunological analysis.

Animals↗
PubMed1983

Coagulogens from four living species of horseshoe crabs (Limulidae): comparison of their biochemical and immunochemical properties.

Coagulogens from four kinds of horseshoe crabs (Limulus polyphemus (LP), Tachypleus tridentatus (TT), Tachypleus gigas (TG), and Carcinoscorpius rotundicauda (CR)) were compared in biochemical and immunochemical properties. On SDS-polyacrylamide gel electrophoresis, the reduced coagulogens had a common apparent molecular weight of 20,000, whereas the molecular weights of unreduced samples were 24,000 for the LP protein and 21,000 for the proteins of the three Asian species (TT, TG, and CR). Gel-filtration yielded apparent molecular weights of 19,500 for the LP protein and 15,500 for the other proteins. All coagulogens consisted of 173-175 amino acid residues and their compositions were very similar to one another, e.g., no methionine, and high proportions of basic amino acids, cystine, valine, and phenylalanine. The amino-terminal 14-residue sequence of the LP coagulogen was Gly-Asp-Pro-Asn-Val-Pro-Thr-Cys-Leu-Cys-Glu-Glu-Pro-Thr. Those of the other coagulogens, Ala-Asp-Thr-Asn-Ala-Pro-Ile-Cys-Leu-Cys-Asp-Glu-Pro-Gly, were identical to one another except for the amino-terminal aspartic acid residue of the TG protein and leucine of the CR protein. The carboxyl-terminal residues of the coagulogens were identified as serine (LP), phenylalanine (TT and TG), and tyrosine (CR), respectively. An antiserum to the LP coagulogen produced a single precipitin line against the LP protein but none against the Asian coagulogens. On the other hand, each of the antiserums to TT, TG, and CR coagulogens yielded a precipitin line against the Asian proteins but gave no line against the LP protein.

Amino Acid Sequence↗
PubMed1983

[Concept of therapeutic ratio in radiation combined with chemotherapy].

Significance of combined therapy should be based in improvement of treatment results and decrease of side effects not only early but also late injuries. In other word, T.R. should be estimated whether direction of it is improvement or not. There are many different factors and difficult subjects which are decision of optimum dose, timing of combination, mechanism in synchronous combined therapy, distribution of tumor microcirculation. It is very important in order to improvement of T.R. clinically that we have been watching reactions after treatment closely and accumulating their datas.

Carcinoma, Small Cell↗