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T Abiko

Publications and source records attributed to T Abiko.

At least 19 recordsLinked to original sources
PubMed1992

Solid-phase syntheses of two deacetyl-thymosin alpha 1 analogues with substitution at position 21 and their effects on low E-rosette-forming lymphocytes of uremic patients.

Two deacetyl-thymosin alpha 1 analogues containing Phe or Phe(4F) at position 21 were synthesized by the manual solid-phase method and their immunological effects on the low E-rosette-forming lymphocytes of uremic patients were studied. Fluorination of the p-position of Phe21 resulted in a marked restorative effect on the low E-rosette-forming lymphocytes of uremic patients compared with that of [Phe21]deacetyl-thymosin alpha 1. The synthetic [Phe21]deacetyl-thymosin alpha 1 was approximately equal in potency to our synthetic deacetyl-thymosin alpha 1 in uremic patients.

Amino Acid Sequence↗
PubMed1991

Synthesis of rat parathymosin alpha fragment 1-28 and examination of its inhibitory activity towards the restoring activity of thymosin alpha 1 on the impaired T-lymphocytes of uremic patients.

A fragment corresponding to N-terminal octaeicosapeptide of rat parathymosin alpha was synthesized by assembling 5 peptide fragments, followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole (molar ratio 1:1) in trifluoroacetic acid in the presence of dimethylselenium. Incubation of impaired T-lymphocytes isolated from uremic patients with the synthetic parathymosin alpha fragment 1-28 showed no immunological restoring effect, but when it was administered together with thymosin alpha 1, it appeared to suppress the restoring effect of the thymosin alpha 1 on the impaired T-lymphocytes of uremic patients.

Amino Acid Sequence↗
PubMed1991

Synthesis of an immunologically active fragment analog of prothymosin alpha with enhanced enzymatic stability.

A fragment analog, [D-Arg30]prothymosin alpha fragment 1-30, containing D-arginine in place of arginine residue at position 30 was synthesized by the liquid phase procedure and studied for immunological effect on the impaired blastogenic response of T-lymphocytes isolated from uremic patients after treatment of human serum. Deacetyl-thymosin alpha 1, a synthetic octaeicosapeptide corresponding to deacetyl-prothymosin alpha fragment 1-28, has restoration ability for the impaired blastogenic response of T-lymphocytes of uremic patients but is susceptible to proteolytic digestion. On the other hand, the fragment analog, [D-Arg30]prothymosin alpha fragment 1-30 retained activity and was shown to exhibit a high degree of stability when incubated in human serum. These results indicate that N-terminal acetylation and the introduction of D-residue into the C-terminal residue of prothymosin alpha fragment 1-30 increase resistance to proteolytic degradation by exopeptidases.

Amino Acid Sequence↗
PubMed1991

Solid-phase synthesis of biologically active fragment 29-111 of rat prothymosin alpha.

Rat prothymosin alpha fragment 29-111, an 83-residue polypeptide corresponding to desthymosin alpha 1-prothymosin alpha, has been synthesized by a solid-phase method. Hydrogen fluoride was used to deprotect and cleave the peptide from the resin. The crude product was purified by gel-filtration, ion-exchange chromatography and high-performance liquid chromatography. A 3.2-mg sample of a ca. 96% pure peptide was finally obtained. The overall yield of the synthesis was less than 1%. An increase of E-rosette-forming lymphocytes was obtained after incubation of peripheral blood from uremic patients with the synthetic prothymosin alpha fragment 29-111. The restoring effect of the synthetic prothymosin alpha fragment 29-111 was greater than that of our synthetic thymosin alpha 1.

Amino Acid Sequence↗
PubMed1990

Arterial injury-induced smooth muscle cell proliferation in rats is accompanied by increase in polyamine synthesis and level.

Proliferation of smooth muscle cells (SMC), enhancement of polyamine biosynthesis and increase in polyamine level in response to deendothelialization in the rat aorta were studied. [3H]Thymidine incorporation into SMC in aortas denuded with a balloon catheter began 25 h after injury, and maximal incorporation occurred 33-37 h after injury. Afterwards, [3H]thymidine incorporation declined, approaching the baseline level, but was slightly higher than that of sham-operated controls until 14 days after injury. Intimal thickening started 7 days after injury, and peaked at 21 days. Prior to these proliferative changes in aortic SMC, a rapid and transient increase in ornithine decarboxylase (ODC) activity was observed within 8 h after injury. There was no significant difference in ODC activity between injured and intact aortas after 4 days. The levels of polyamines, putrescine, spermidine, and spermine increased and were maximal at 48 h after injury, 8.1, 3.4 and 1.4 times the control levels, respectively. Increased levels of polyamines, in particular spermidine, continued until 7 days after injury. These results suggest that the enhancement of polyamine synthesis and the increased polyamine content of the aorta play important roles in the proliferation of SMC and in the development of intimal thickening, particularly in the initial proliferative response of medial SMC after deendothelialization.

Animals↗
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.

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Amino Acid Sequence↗