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Biomedical subjects

T Abiko

Publications and source records attributed to T Abiko.

At least 55 records · Page 3Linked to original sources
PubMed1990

Synthesis of a thymosin beta 4-like peptide, thymosin beta Met9, and its effect on low E-rosette-forming lymphocytes of lupus nephritis patients.

A thymosin beta 4-like peptide, thymosin beta Met9 isolated from pork spleen, was synthesized using a conventional solution method. The deprotection of the protected thymosin beta Met9 was achieved by treatment with Zn-90% AcOH to remove C-terminal p-nitrobenzyl ester and then with 1 M trifluoromethanesulfonic acid-thioanisole (molar ratio, 1:1) in trifluoroacetic acid in the presence of dimethylselenium. Finally, the deprotected peptide was incubated with dithiothreitol to reduce sulfoxide on the methionine side chain. The increase of the E-rosette-forming lymphocytes was obtained after incubation of peripheral blood from lupus nephritis patients with the synthetic thymosin beta Met9. The synthetic thymosin beta Met9 was approximately equal in potency to that of our synthetic calf thymosin beta 9.

Amino Acid Sequence↗
PubMed1990

Immunological effect of two synthetic peptides containing alanine or D-alanine instead of acetyl group of thymosin beta 4 after treatment of human serum.

Two analogs of thymosin beta 4 the N-terminal acetyl groups of which were substituted by Ala or D-Ala, were synthesized by the solution method and studied for their immunological effect on the impaired blastogenic response of T-lymphocytes isolated from uremic patients after treatment of human serum. One of the synthetic analogs, D-Ala-thymosin beta 4 demonstrated a restorative effect on these patients when incubated in human serum, but the other analog, Ala-thymosin beta 4, showed no restorative effect under the same conditions. These results seem to suggest that D-Ala-thymosin beta 4 increases resistance to proteolytic degradation by exopeptidases more than Ala-thymosin beta 4.

Alanine↗
PubMed1990

Synthesis of human splenin (hSP) and examination of its immunological effects on the impaired T- and B-lymphocytes in uremic patients.

Human splenin (hSP) was synthesized by assembling eight peptide fragments followed by deprotection with 1M trifluoromethanesulfonic acid-thioanisole (molar ratios, 1:1) in trifluoroacetic acid in the presence of m-cresol and dimethylselenium. Finally, the deprotected peptide was incubated with dithiothreitol to reduce sulfoxide on the methionine side chain. Incubation of peripheral lymphocytes isolated from uremic patients with the synthetic hSP showed an enhancing effect on the reduced B-lymphocytes, but had no restoring effect on the impaired blastogenic response of T-lymphocytes.

Amino Acid Sequence↗
PubMed1989

Synthesis of a thymosin beta 4-like peptide, deacetyl-thymosin beta Xen4, and its restorative effect on depressed lymphocyte blastogenic response to phytohemagglutinin (PHA) in uremic patients.

An analog of thymosin beta Xen4 isolated from oocytes of Xenopus laevis, deacetyl-thymosin beta Xen4, was synthesized by assembling 6 peptide fragments, followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole (molar ratio, 1:1) in trifluoroacetic acid in the presence of dimethylselenium. Finally, the deprotected peptide was incubated with dithiothreitol to reduce sulfoxide on the methionine side chain. The synthetic tritetracontapeptide was found to have a restoring effect on the impaired blastogenic response of T-lymphocytes isolated from uremic patients.

Amino Acid Sequence↗
PubMed1989

Syntheses and effects of human splenin (hSP) fragment 32-48 and an analog on the reduced B-lymphocytes of uremic patients.

A heptadecapeptide, H-Arg-Lys-Ala-Val-Tyr-Val-Glu-Leu-Tyr-Leu-Gln-Ser-Leu-Thr-Ala-Glu-His-OH , corresponding to amino acids 32 to 48 of human splenin (hSP) and an analog in which the amino acid residue at position 34 is changed from Ala to Glu, were synthesized. These peptides were synthesized using conventional solution synthesis and were tested for their effect on reduced B-lymphocytes of uremic patients. Incubation of peripheral lymphocytes isolated from uremic patients with these two synthetic heptadecapeptides, hSP fragment 32-48 and [Glu34]hSP fragment 32-48, had an enhancing effect on the reduced B-lymphocytes, but synthetic bovine thymopoietin II (bTP-II) fragment 32-49 had no effect under the same conditions.

Amino Acid Sequence↗
PubMed1989

Synthesis of [Glu34]human splenin (hSP) and examination of its immunological effect on the reduced B-lymphocytes of uremic patients.

[Glu34]human splenin (hSP) was synthesized in a conventional manner by assembling ten peptide fragments followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole (molar ratio, 1:1) in trifluoroacetic acid in the presence of m-cresol and dimethylselenide. Finally, the deprotected peptide was incubated with dithiothreitol to reduce sulfoxide on the methionine side chain. Incubation of peripheral lymphocytes isolated from uremic patients with the synthetic [Glu34]hSP showed an enhancing effect on the reduced B-lymphocytes, but synthetic human thymopoietin (hTP) had no effect under the same conditions.

Amino Acid Sequence↗
PubMed1988

Synthesis of deacetylthymosin beta 11 and its effect on the impaired T-lymphocytes of a uremic patient with common variable immunodeficiency.

The untetracontapeptide corresponding to the entire amino acid sequence of deacetylthymosin beta 11 was synthesized by assembling six peptide fragments via the azide followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole in trifluoroacetic acid in the presence of dimethylselenide. The synthetic peptide was tested for its effect on the impaired blastogenic response of phytohemagglutinin-stimulated T-lymphocytes of a uremic patient with common variable immunodeficiency. The synthetic peptide had some restoring activity on the impaired blastogenic response of T-lymphocytes in the one patient tested.

Amino Acid Sequence↗
PubMed1987

The Abiko factor.

Explore the source record for details and available documents.

Amino Acid Sequence↗
PubMed1987

The synthesis of peptides with potential thymic hormone activity: the synthesis of endo-Arg38a-deacetylthymosin beta 10.

A tritetracontapeptide corresponding to the entire amino acid sequence of endo-Arg38a-deacetylthymosin beta 10 was synthesized by a conventional solution method. Seven peptide fragments were assembled, followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole-Me2Se in trifluoroacetic acid. In preliminary experiments the synthetic tritetracontapeptide increased the entire peripheral T-cell population and a helper T-cell subset when incubated in vitro with blood which was obtained from a uremic patient with pneumonia, but a suppressor/cytotoxic T-cell subset was unaffected under these conditions. The synthetic endo-Arg38a-deacetylthymosin beta 10 was as active as synthetic deacetylthymosin beta 10 in this in vitro assay.

Amino Acid Sequence↗
PubMed1985

Purification and mode of action of a microsomal endoribonuclease from rat liver.

An endoribonuclease has been purified nearly to homogeneity from rat liver microsomes, and its mode of action and general properties were studied. The enzyme had an apparent molecular weight of 58 000, as estimated by both gel filtration and SDS-polyacrylamide gel electrophoresis and produced oligonucleotides from poly(A), poly(U) and poly(C). No mononucleotide was obtained by the enzymatic hydrolysis of the above substrates. The enzyme made endonucleolytic cleavages which generated 5'-phosphate-terminated oligonucleotides. It was suggested that the existence of at least (Ado5'P)2 residues at both sides of the cleavage bond was necessary for the action of the endoribonuclease. Divalent cations (Mg2+ or Mn2+) were required for the enzymatic activity, while K+ inhibited the enzyme. Spermine stimulated the enzymatic activity in the presence of 1 mM Mg2+.

Animals↗