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Y Yasumuro

Publications and source records attributed to Y Yasumuro.

10 recordsLinked to original sources
PubMed2001

[Clinical significance of a new fibrinogen/fibrin degradation products(FDP) test using plasma samples for the diagnosis of fibrinogenolysis and fibrinolysis].

Recently, a new fibrinogen/fibrin degradation products(FDP) test using monoclonal antibodies against FDP(LPIA FDP-P: FDP-P) has been developed, which is able to measure FDP directly in plasma. The objective of this study is to clarify clinical significance of the test in the diagnosis of fibrinogenolysis and fibrinolysis in comparison with a conventional FDP test using polyclonal antibodies against fibrinogen(FDP-S) and D-dimer test using monoclonal antibodies against D-dimer(D-D). The monoclonal antibodies used in FDP-P test was shown to recognize fragment X, Y and D1 derived from fibrinogen digested by urokinase, and was also to recognize XDP fragments, D-dimer and D derived from cross-linked fibrin digested by tissue plasminogen activator using SDS-PAGE and immunoblotting analysis. There was a good correlation of FDP levels between FDP-P test and FDP-S test. However, levels of FDP in both tests were discrepant in several samples. There was a tendency that the levels of FDP were higher in FDP-S test than in FDP-P test. Such discrepancy was suggesting that soluble fibrin monomer complex(FM) was recognized by the antibodies used in FDP-S test, but not recognized by the antibodies used in FDP-P test. There was also a good correlation of FDP levels between FDP-P test and D-D test. However, the levels of FDP in both tests were discrepant in several samples. The levels of FDP were higher in FDP-P test than in D-D test. These discrepant samples had lower levels of antiplasmin and higher levels of plasmin antiplasmin complex(PIC), and also showed XDP fragments, D-dimer, X, Y, and D1 by using SDS-PAGE. These observations suggest that D-D test measures only fibrinolytic fragments, while FDP-P test measures fibrinogenolytic fragments as well as fibrinolysis. In results, the FDP-P test was confirmed to be a useful tool to examine fibrinogenolysis as well as fibrinolysis more specifically than the conventional FDP test.

Antibodies, Monoclonal↗
PubMed2001

[Laboratory tests for detection of antiphospholipid antibodies].

Antiphospholipid antibodies(APA) have been reported to be a heterogeneous family of immunoglobulins. Some APA can be detected via phospholipid dependent coagulation assays when they present as an aspecific coagulation inhibitor, lupus anticoagulant(LA), other antibodies can be measured via immunological assays mostly via their capability to bind to immobilized cardiolipin (anticardiolipin antibody; aCL). Despite their name, APA associated with antiphospholipid syndrome(APS) do not bind phospholipids, but are directed at plasma proteins bound with anionic phospholipids. The antigenic targets of these antibodies include beta 2 glycoprotein I(beta 2 GP I), prothrombin, high- and low-molecular-weight kininogens, annexin V, protein C and protein S. In this article, the current knowledge on the methods of detection and their functional properties are reviewed, and the interaction of these antibodies and acquired activated protein C resistance are discussed.

Antibodies, Antiphospholipid↗
PubMed2000

An application of apo(a) isoforms for the clinical assessment of Lp(a).

To examine whether or not Lp(a) is applicable as a diagnostic marker for atherosclerosis, we studied the correlation between Lp(a) levels and molecular weights of apo(a) isoforms in sera from both normal healthy adults and diabetic patients. Serum Lp(a) level was measured by turbidimetric immunoassay (TIA) and the molecular weight of apo(a) isoform was determined by Western blotting analysis. The serum Lp(a) levels of the diabetic patients (25.0 mg/dl +/- 2.2 [mean +/- SE], n = 54) were significantly higher than those of the normal subjects (14.4 mg/dl +/- 0.57, n = 500). With respect to the correlation between serum Lp(a) levels and the molecular weights of apo(a) isoforms, there was an inverse correlation in sera from normal subjects (n = 298), whereas there was no correlation in sera from the diabetic patients. Statistical significant inverse correlation (r = -0.91, y = 224.25 - 3.07x) was especially observed in 50 representative apo(a) isotypes from the normal subjects. By applying a standardized curve based on the significant inverse correlation to serum Lp(a) levels, 40.7% (22/54) of the diabetic patients were revealed to have an abnormally high value of serum Lp(a). Moreover, it was found that the significantly higher mean value of serum Lp(a) in the diabetic group was caused by the 22 patients with higher value of Lp(a). The present findings suggest that determination of apo(a) isoform size provides estimation of the serum Lp(a) value and that the inverse correlation curve between serum Lp(a) level and the molecular weight of apo(a) isoform may be applicable to the clinical use of Lp(a).

Adult↗
PubMed1998

Genetic analysis of protein C deficiency in nineteen Japanese families: five recurrent defects can explain half of the deficiencies.

We have been studying the molecular basis of protein C deficiency. In this study, we determined the molecular defects of protein C deficiency in 19 Japanese families by using a strategy combining polymerase chain reaction (PCR) and single-strand conformational polymorphism (SSCP) analysis. We identified 10 missense mutations, 1 in-frame deletion, 1 frameshift deletion, 1 frameshift addition, and 1 splice site mutation, 5 of which were novel. From the results of genetic analysis of 67 Japanese families with protein C deficiency reported in this and previous studies, the recurrent defects including Phe139Val and Met365Ile substitutions and a Lys150 d letion, a G8857 deletion, and a splice site mutation of G3079A were only found in Japanese subjects and seemed to be a founder effect. In contrast, Arg169Trp, Arg286His, Val297Met, and Asp359Asn substitutions, all occurring at CG dinucleotides, were commonly observed in not only Japanese but also Western populations, indicating that these are hot spots for mutation in the protein C gene. These 9 recurrent molecular defects were found in 43 families in total, accounting 64% of Japanese families with protein C deficiency. In particular, the recurrent defects of Phe139Val, Arg169Trp, Va1297Met, and Met36-4Ile substitutions and a G8857 deletion were found in 33 families in total, accounting for 49% of Japanese families with protein C deficiency. For the identification of the genetic defect in Japanese patients with protein C deficiency, screening of these recurrent defects by using restriction enzyme cleavage is a rational method.

Exons↗
PubMed1997

[Improvement of inter-assay for the standardization of PT and TT--clinical significance of local standardization method].

We performed a nationwide Inter-assay including 112 laboratories for the standardization of prothrombin time (PT) and thrombotest (TT). The data were expressed as seconds, percentile and INR. INR was expressed by 2 methods; Method I (conventional method): INR was expressed using each ISI assigned for reagent or reagent-instrument at the respective laboratories and Method II (local standardization method): INR was expressed using each reference curve created with INR assigned standard plasmas at the respective laboratories. (1) Sample distribution of PT as well as TT was the smallest with the data expressed by Method II followed by Method I and then by percentile. The data expressed by seconds was widely distributed and not useful for the standardization of PT and TT. (2) Even the sample distribution obtained by Method II was dependent on the different ISI of the reagents, as it was found that the larger the ISI of the reagents, the wider the distribution of data. (3) The difference between PT and TT of each test plasma was analysed by t-test. It was found that the difference was insignificant when both data were expressed by Method II, but significant when expressed by Method I, suggesting that PT and TT were interchangeable with the use of Method II. (4) Sample distribution of percentile expression and INR with the use of method II was compared. It was revealed that the sample distribution of INR was smaller than that of percentile. It was concluded that INR expressed by the local standardization method was most useful for the standardization of PT and TT.

Humans↗
PubMed1996

[Evaluation of sensitivity and specificity of confirmatory assays for lupus anticoagulant (LA) detection].

To evaluate the sensitivity and specificity of confirmatory assays for LA detection, we performed the platelet neutralization procedure (PNP), diluted Russell's viper venom time (dRVVT) confirmatory assay (the ratio of LA-screen and LA-confirm:S/C), and specific hexagonal phase neutralization test (StaLA) on, plasma samples 43 LA-positive in either the ratio of dilute APTT and APTT(dAPTT/APTT) or dRVVT(LA-screen). The sensitivity and the specificity were evaluated by 4 different analyses based on, 1) maximal plasma dilution, 2) correlation between the screening assays and these confirmatory assays, 3) ratio of LA-positive in the confirmatory assays, and 4) receiver operation characteristic (ROC) method. All 4 analyses showed that sensitivity was in the order of PNP > S/C > Staclot-LA. However, the order of the specificity evaluated by the ROC method was Staclot-LA > S/C > PNP. The APTT-based confirmatory assay, PNP can detect LA of the plasma samples that were all positive in the dAPTT/APTT ratio, while the LA-positive plasma samples in dRVVT-confirm were all positive in the dRVVT-screen assay. Our findings suggest that confirmatory assays should be based on the method giving an abnormal screening assay. Accordingly, we recommend the following combinations of screening and confirmatory assays in terms of specificity; 1) dAPTT/APTT ratio and Staclot-LA as the APTT-based assay, and 2) LA-screen and LA-confirm as the dRVVT-based assay.

Blood Coagulation Tests↗
PubMed1992

[Influence of aging and circadian fluctuation of fibrinolytic factors to the responses of these factors during venous occlusion test in healthy subjects].

This study was aimed to clarify the influence of aging and circadian fluctuation of fibrinolytic factors to changes of tissue plasminogen (t-PA) and its inhibitor (PAI-I) during venous occlusion test. Venous occlusion was achieved by application of a sphygmomanometer cuff to the upper arm of elderly healthy subjects (n = 12) and young healthy subjects (n = 12) at 10:00 am and 4:00 pm. Plasma concentration of t-PA, free PAI-1 and total PAI-1 were measured by ELISA. The activity of t-PA was measured by bioimmunoassay using monoclonal antibody for t-PA. Circadian variation was observed in the change of t-PA activity and total PAI-1. These were highly increased in the evening. However, this phenomenon was different between age groups and increase of t-PA activity occurred in elderly subjects, whereas PAI-1 was observed in young subjects. In conclusion, circadian variation and the influence of age should be considered to evaluate results of venous occlusion test.

Adult↗
PubMed1991

[von Willebrand factor multimer analysis using electroblotting and immunoperoxidase staining method].

Further modification of the previously reported peroxidase staining method for von Willebrand factor (vWF) multimer is described in this article. The alteration are as follows: affinity purified anti-human vWF rabbit IgG was replaced by commercial anti-human vWF rabbit IgG, and washing and reaction steps were shortened markedly. Despite these modification, the resolution of vWF multimers on the nitrocellulose membrane remains comparable to the autoradiography. However, unlike autoradiography, results produced by this method can be obtained in a day. The features of this method are especially useful in clinical laboratories where both time and equipments are limited.

Humans↗
PubMed1990

Reference values of hemostasis related factors of healthy Japanese adults. I: Circadian fluctuation.

The circadian fluctuation of hemostasis related parameters was examined on 16 healthy Japanese adults (male 9, female 7). Twenty one parameters were measured in this study, i.e. fibrinogen, the activity of F.II, F.V., F.VII, F.VIII, F.IX, F.X., F.XI, F.XII, antithrombin III, plasminogen, alpha 2-antiplasmin, as well as the antigen level of F.IX, von Willebrand Factor, protein C, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), beta-thromboglobulin, platelet factor 4, fibrinopeptide A, plasmin-alpha 2-antiplasmin complex and FDP. Fluctuation was not significant in almost all of the parameters except F.VIII, F.IX, beta-thromboglobulin, platelet factor 4, tPA and PAI-1. Although the fluctuations of F.VIII, F.IX, beta-thromboglobulin and platelet factor 4 were statistically significant, they remained within the normal ranges. On the other hand, tPA and free PAI-1 showed significant circadian fluctuation, of which levels were highest at 9:00. It was postulated that the significant circadian fluctuation of fibrinolytic activity will be regulated by the balance between tPA and PAI-1 in plasma.

Adult↗