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Biomedical subjects

K Yamazumi

Publications and source records attributed to K Yamazumi.

24 records · Page 2Linked to original sources
PubMed1989

A gamma methionine-310 to threonine substitution and consequent N-glycosylation at gamma asparagine-308 identified in a congenital dysfibrinogenemia associated with posttraumatic bleeding, fibrinogen Asahi.

In an abnormal fibrinogen with severely impaired polymerization of fibrin monomers, we identified a methionine-to-threonine substitution at position 310 of the gamma chain. Furthermore, asparagine at position 308 was found to be N-glycosylated due to a newly formed consensus sequence, asparagine(308)-glycine(309)-threonine(310). The two structural defects in the mutant gamma chain may well perturb the conformation required for fibrin monomer polymerization that is specifically assigned to the D domain of fibrinogen. This alteration also seems to affect the intermolecular gamma chain cross-linking of fibrin and fibrinogen, although the amine acceptor gamma glutamine-398 was found to function normally. These functional abnormalities may well be related to posttraumatic hemorrhage as observed in a 33-yr-old man with moderate hemorrhagic diathesis related to injuries since his early adolescence. The structure of the extra carbohydrate moiety attached to asparagine-308 was found to be identical with those derived from the normal B beta and gamma chains as evidenced by HPLC.

Adult↗
PubMed1989

Fibrinogen Sapporo: dysfibrinogenemia characterized by the replacement of A alpha arginine-16 by histidine resulting in the delayed release of fibrinopeptide A by thrombin.

Congenital dysfibrinogenemia was found in a 60-year-old asymptomatic female and her daughter. Purified fibrinogen derived from the propositus, apparently a heterozygote for the abnormality, characteristically showed delayed but complete release of fibrinopeptide A upon digestion with thrombin but its defective release by Ancrod, a snake venom enzyme, from half of her fibrinogen molecules. This congenital dysfibrinogenemia with an A alpha arginine (Arg) to histidine (His) substitution was tentatively designated as fibrinogen Sapporo. Although this type of abnormal fibrinogen had been identified among Caucasians, no such cases have so far been reported in Japan.

Female↗
PubMed1989

Fibrinogen Kyoto III: a congenital dysfibrinogen with a gamma aspartic acid-330 to tyrosine substitution manifesting impaired fibrin monomer polymerization.

A congenital dysfibrinogen characterized by impaired fibrin monomer polymerization was found in an asymptomatic 50-year-old woman and her two sons. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) run according to the method of Laemmli, we noticed two gamma chain species in fibrinogen and its plasmic fragments D1 and D2, consisting of a normal species and an apparently lower molecular weight (mol wt) variant in respective fractions. However, in fragment D3 only a single gamma chain remnant was observed. By chromatofocusing of the plasmic-CaCl2 digests of the abnormal fibrinogen, we separately isolated the normal and abnormal D1 species, the latter having been eluted in a slightly higher pH range. As expected, the abnormal D1 species failed to interfere with thrombin clotting of normal fibrinogen and normal fibrin monomer polymerization, whereas the normal D1 species inhibited them markedly. By analyzing the lysyl endopeptidase digests of the isolated gamma chain, we identified a replacement of aspartic acid by tyrosine at position 330 of the mutant gamma chain. The point mutation from an aspartic acid (pK for the beta-carboxyl = 3.86) to a tyrosine (pK for the aromatic hydroxyl = 10.07) may have perturbed the folding gamma chain structure in the D domain of fibrinogen specifically required for polymerization.

Amino Acid Sequence↗
PubMed1988

Normal plasmic cleavage of the gamma-chain variant of "fibrinogen Saga" with an Arg-275 to His substitution.

We have identified a gamma-Arg-275 to His substitution in an abnormal fibrinogen designated as "fibrinogen Saga" characterized by impaired fibrin monomer polymerization. By chromatofocusing chromatography, we isolated normal and abnormal fragment D1 populations separately from the plasmic-calcium digests of fibrinogen derived from the propositus, a heterozygote for the abnormality. We found that both normal and abnormal fragment D1's were similarly protected from digestion by plasmin in the presence of calcium ions and further degraded to fragments D2 and D3 due to cleavage of the gamma-chain remnant when calcium ions were replaced by chelating agents. Abnormal fragment D1 failed to inhibit both thrombin-clotting of normal fibrinogen and polymerization of normal fibrin monomer, while normal D1 exhibited marked inhibitory activities. In an aberrant peptide comprising residues gamma-274-302 isolated by HPLC from the lysyl endopeptidase-digests of abnormal fragment D1, we identified a His substituting for an Arg at position 2, which corresponds to position 275 of the mutant gamma-chain.

Adolescent↗
PubMedDate not supplied

Retroperitoneal foregut cyst.

A foregut cyst is formed as a result of abnormal budding and pinching of the tracheobronchial tree when bronchial buds develop to form the primitive respiratory tree. Foregut cysts are clinically classified as bronchogenic, esophageal, enterogastric, or ciliated hepatic. We present a foregut cyst that occurred in the retroperitoneum and was difficult to distinguish from other retroperitoneal cystic mass lesions. Magnetic resonance imaging was useful in revealing the cyst's continuity to adjacent organs.

Aged↗