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Biomedical subjects

C Miyashita

Publications and source records attributed to C Miyashita.

At least 19 recordsLinked to original sources
PubMed1992

Fibrinolytic effects of pro-urokinase combined with low-dose urokinase compared to high-dose urokinase in patients with acute myocardial infarction.

20 patients (6 females, 14 males) aged between 47 and and 75 years (mean: 62.6 yrs.) with acute myocardial infarction (onset of symptoms within 6 hours) were treated intravenously with either 200,000 U urokinase (UK) and 4.5 million U pro-urokinase (pro-UK) within 60 min (group I, N = 10), or 2.5 million U UK within 5 min (group II, N = 10). Blood samples for haemostatic and fibrinolytic function tests were taken prior to and repeatedly during the 24 hours following treatment. Peak fibrinolytic activity measured by fibrin plates was equivalent in both regimens. Average decreases, with lowest levels within 60 to 120 min following thrombolytic therapy, were observed of 27% and 70% for plasminogen, of 71% and 91% for alpha-2-antiplasmin, and of 20% and 74% for fibrinogen in group I and II, respectively. The reptilase time reached maximum values of 1.5- and 4.5-fold within 60 to 180 min. Peak levels of D-dimers and thrombin-antithrombin III complexes in group II were 2.6 and 3.2 times those of group I. After 24 hours, in contrast to group I, all these parameters still remained significantly different from pretreatment values in group II. These data indicate that, contrary to high-dose UK, pro-UK in combination with low-dose UK causes minor systemic fibrinolytic effects and is, therefore, assumed to be largely clot-specific, although the fibrinolytic potential is equivalent for both regimens.

Aged↗
PubMed1991

Half-life of single-chain urokinase-type plasminogen activator (scu-PA) and two-chain urokinase-type plasminogen activator (tcu-PA) in patients with acute myocardial infarction.

The pharmacokinetics of urokinase (two-chain urokinase-type plasminogen activator, tcu-PA) and single-chain urokinase-type plasminogen activator (scu-PA) were studied in 20 patients with acute myocardial infarction (AMI). Ten consecutive patients received 2.5 million units tcu-PA by bolus injection within 5 min during the first 6 h after AMI (group I). Ten further consecutive patients received 250,000 U tcu-PA within 5 min, followed by 4.5 million U scu-PA by intravenous infusion over 40 min (group II). An enzyme immunoassay was developed for urokinase antigen determinations, and a fibrin plate assay for determinations of fibrinolytic activity was applied. Using a 3-compartment model, in group I 98% of urokinase antigen were cleared with a half-life of 60.8 min. After scu-PA, urokinase antigen was cleared with half-lives (area under the curve in parentheses) of 6.9 min (74.8%), 26.5 min (23.6%), and 329.7 min (2.2%). The half-disappearance times of fibrinolytic activity were 18 and 8 min in group I and II, respectively. A more pronounced decrease of plasminogen was observed after tcu-PA.

Half-Life↗
PubMed1990

Comparison of different prothrombin complex concentrates--in vitro and in vivo studies.

The potency and tests for thrombogenicity were studied prospectively in 7 different (two lots of each brand, A-G) prothrombin complex concentrates (PCC). Human albumine (H) and a factor IX concentrate (I), served as controls. The potency of coagulation factors and inhibitors varied considerably. Two brands (E, F) contained no protein S, additionally one brand contained no protein C. Two preparations exhibited high amidolytic activities, especially towards the thrombin-sensitive chromogenic substrate S-2238, in vitro. These activities could be quenched in part by the addition of hirudin or antithrombin III. The heparin and antithrombin III content of the PCCs was significantly different, and, after addition of antithrombin III an increase of thrombin-antithrombin III complexes in 2 preparations (B, D) was observed in vitro. Additionally, three brands (B, D, F) caused more severe cardio-pulmonary reactions in rabbits, associated with an increase of fibrin split products for brands B and D. We conclude that the use of these preparations in patients, in whom an acquired protein C or S defect, or a hypercoagulable state, can be suspected, cannot be recommended.

Animals↗
PubMed1990

Modern strategies for treatment of acute myocardial infarction: significance of haemostaseological and rheological findings.

In spite of equivalent clinical efficacy of various thrombolytic agents for the treatment of acute myocardial infarction there is evidence of different drug-depending influences on the haemostatic and fibrinolytic system. In the present study 40 patients with acute myocardial infarction have been investigated. 20 patients received 750,000 and 1.5 mio U streptokinase (SK), respectively, 10 patients 30 mg anisoylated plasminogen streptokinase activator complex (BRL 26921) and 10 patients a combination of 200,000 U urokinase (UK) and 4.5 mio U pro-urokinase (PUK) as a short-term intravenous treatment. Reperfusion of coronary arteries has been achieved in 70 to 100 percent. Major not fatal bleedings occurred in 2 patients. One patient died within 72 hours after beginning of the myocardial infarction. The longest duration of fibrinolytic activity was observed in the BRL 26921 group (half-disappearance time close to 2 h). It was significantly shorter in the SK groups showing a dose-dependency. Plasma concentration of fibrinogen dropped beyond normal levels following SK and BRL 26921, but not under UK/PUK. Plasma viscosity correlated with fibrinogen decrease and displayed a dose-depending relationship with the presence of SK. Haemorheological effects are suggested to be important for the clinical efficacy of thrombolytic therapy in myocardial infarction.

Anistreplase↗
PubMed1990

The development of a central register for side effects of biomaterials.

Examination of the interaction between biomaterials and tissues from a clinical realistic as well as scientific viewpoint to complement the highly advanced experimental and biochemical basis research is an undertaking that has suffered a considerable amount of neglect in the past. Attempts to realize internationally a Central Registry for documenting clinically relevant side effects will be reported in detail. Implementation of the registry involves the review of present literature (prospective clinical studies, retrospective studies and case reports). An "incompatibility incident report/questionnaire" has been developed according to the guidelines of the "Report on Pharmacological Side Effects" of the Pharmaceutical Commission of the German Medical Association. The aims of registering and evaluating these reports will be demonstrated and discussed in detail.

Biocompatible Materials↗
PubMed1990

[Quality control of prothrombin complex preparations: in vivo and in vitro findings].

Prothrombin complex concentrates (PCC) are frequently used for the treatment of acquired coagulation factor deficiencies. However, a major problem when using these preparations is their thrombogenic potential. Thus, the potency and tests for thrombogenicity were studied prospectively in 7 different PCC's. Human albumine and a factor IX concentrate served as controls. The potency of coagulation factors and inhibitors varied considerably, especially for proteins S and C. Two preparations exhibited high amidolytic activities in vitro. These activities could be quenched in part by the addition of hirudin or antithrombin III. Additionally, these two preparations caused more severe cardiopulmonary reactions in rabbits and an increase of fibrin split products. We conclude that the use of these preparations in patients, in whom an acquired protein C or S defect, or a hypercoagulable state, can be suspected, cannot be recommended.

Blood Coagulation Factors↗
PubMed1988

In vivo recovery and half-life time of a steam-treated factor IX concentrate in hemophilia B patients. The influence of reagents and standards.

Factor IX (FIX) recovery and half-life was measured in ten hemophilia B patients under standardized conditions. Each patient received a steam-treated high-purity factor IX concentrate at a dose of 19-39 U/kg body weight. FIX activity was determined using a one-stage assay, which was calibrated against the international concentrate standard (reagents from Immuno, Heidelberg). The in vivo recovery ranged from 24% to 53% (mean value 37.7%) and the half-disappearance time (HDT) from 8-30 h (mean 16.7 h). In four of the ten patients, the distribution and elimination half-lives were estimated and ranged from 0.3 h to 3.9 h (mean 1.4 h) and from 28.6 h to 39.7 h (mean 33.1 h), respectively. In six patients FIX was redetermined using a different FIX deficient plasma and a plasma standard (reagents from Merz & Dade, Munich, FRG). Recoveries and HDT based on the results obtained with this method were significantly higher (68.2% vs 39.7%; p less than 0.05), and longer (14.8 h vs 10.6 h; p less than 0.05), respectively. FIX activity was also measured by both assay systems in 100 healthy subjects (50 males, 50 females). The reagents from Immuno yielded a mean value of 0.77 U/ml, while the mean FIX activity utilizing standards and reagents from Merz & Dade was 1.11 U/ml (p less than 0.000001). The coefficient of correlation between the FIX activity measurements, as determined in 100 healthy subjects and 6 hemophilia B patients using the different test systems, was r = 0.9 (N = 159; y = 0.08 +/- 1.3* chi; p less than 0.001). Our data suggest that recovery and HDT of factor IX concentrate strongly depend on the assay and calibration conditions and that an international FIX activity plasma standard is urgently required.

Adolescent↗
PubMed1988

Plasminogen: a brief introduction into its biochemistry and function.

Human plasminogen is a beta-globulin (2% carbohydrate, molecular weight 90 KD), which in its native form has NH2-terminal glutamic acid (Glu-plasminogen) whose primary structure is known (31, 37, 38). From human plasma plasminogen can easily be isolated by affinity chromatography techniques (10, 25, and Table 1). Plasminogen is synthesized in many organs. The production site of the zymogen may be the liver (21), the eosinophiles (3) or the kidney (15). The plasma-plasminogen level is low in newborns (22) and even lower in the premature infant (2). In healthy adults it is found in plasma or serum in a concentration of 200 mg/l (= 2 microM, 22, 39). The half-life of the native (Glu-) plasminogen is 2.24 +/- 0.29 days (6). Two types of Glu-plasminogen occur in human plasma, which differ in their carbohydrate composition as well as in their content of sialic acid. Genetic variants (see Mayr, 3.1.); of plasminogen have been reported (16) after isoelectric focusing of human plasma in polyacrylamide gels. Three patterns were found, two completely different and the third most likely a mixture of the other two. Characteristical functional properties of plasminogen are related to its molecular structure, e.g. its in vivo specificity for fibrin in contrast to the fairly unspecific in vitro activity of plasmin. Glu-plasminogen is easily converted by limited plasmic digestion to modified forms with NH2-terminal lysine, valine or methionine, which are commonly designated "Lys-plasminogen" displaying a plasma half-life time of 0.8 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Conformation↗
PubMed1988

Reference values and variability of plasminogen in healthy blood donors and its relation to parameters of the fibrinolytic system.

During a survey of four month's duration the following parameters were determined in 43 healthy blood donors (22 males, 21 females; mean age 29 years/20-49/): plasminogen activity, plasminogen concentration, alpha 2-antiplasmin (alpha 2-AP) activity, alpha 2-AP concentration, tissue type plasminogen activator (t-PA) activity, t-PA concentration, plasminogen activator inhibitor--I (PAI-I) activity, AT III activity, AT III concentration and heparin cofactor II (HC II) activity. Normal values including standard deviation (x +/- 2s) were: plasminogen activity: 96.3% (65.9-126.8), plasminogen concentration: 12.2 mg/dl (7.7-16.8), alpha 2-AP activity: 99.9% (83.8-116), alpha 2-AP concentration: 108.1% (84.5-131.8), t-PA activity: 0.85 IU/l (0.0-1.92), t-PA concentration: 10.3 ng/ml (2.5-18.1), PAI-I activity: 15.2 AU/ml, AT III activity: 111.4% (87.8-134.9), AT III concentration: 31.6 mg/dl (24.2-39.1) and HC II activity: 110.7% (81.4-140.0). Concerning plasminogen values no sex related difference could be stated. Women who were smokers and used oral contraceptives tended to present elevated t-PA activity levels due to a lower activity of PAI-I, although this tendency was not significant. Determining concentration and activity of components in the fibrinolytic system plays an important part in the diagnosis, therapy and prognosis of thrombophilic disorders.

Adult↗
PubMed1988

Characterization of commercially available plasminogen preparations in vitro: purity and reactivity.

Three different commercially available plasminogen preparations (Immuno-, Kabi-, and Behring-plasminogens) were examined regarding purity and reactivity to different activators (high molecular weight [HMW] or low molecular weight [LMW] two-chain urokinase type plasminogen activator [tcu-PA], single chain urokinase type plasminogen activator [scu-PA], tissue type plasminogen activator [t-PA], and streptokinase [SK]). The Immuno-preparation was a Lys-plasminogen, commercially available for therapeutical use, whereas the research reagents for KabiVitrum and Behringwerke were Glu-plasminogen. Activity data provided by the manufacturers correlated well with our findings. Also a good correlation of reactivity to activators measured with a chromogenic substrate and on fibrin plates could be observed. The Immuno-plasminogen showed a minimum contamination with plasmin which has to be taken into consideration for the interpretation for its apparently higher activation by plasminogen activators compared to the plasmin-free plasminogens. Further in vitro and in vivo research has to be performed to find out criteria for a practicable scheme of administration of fibrinolytic agents for therapeutical thrombolysis.

Electrophoresis, Polyacrylamide Gel↗
PubMed1988

[Problems in measuring parameters of the fibrinolytic system: circadian rhythm of tissue-type plasminogen activator and plasminogen activator inhibitor].

Reference values of tissue-type plasminogen activator (t-PA) antigen, t-PA activity, and plasminogen activator inhibitor (PAI) were established in healthy blood donors using different assay systems. Significant differences between male and female donors were found, due to the intake of oral contraceptives. PAI-activity determinations, using the method described by Chmielewska et al. (1983) or the modification by KabiVitrum, were only poorly correlated (r = 0.53; N = 98; p greater than 0.0001). PAI-activity (Chmielewska et al. 1983) determinations and t-PA antigen measurements were also significantly correlated (r = 0.52; N = 96), which may be a consequence of a joint regulation. In a second series, the diurnal variations of t-PA and PAI were investigated in blood donors (N = 83). PAI-activity and t-PA antigen were about 30 to 40 percent decreased in the evening hours, when compared with the morning values. In two controlled studies, the acute effects of heparins and desmopressin (DDAVP) on the fibrinolytic system were investigated in healthy individuals (N = 10). Again, a pronounced diurnal variation of t-PA and PAI was found. PAI and t-PA were significantly higher in the morning when compared with the evening. However, t-PA activity (Verheijen et al. 1982) showed a reversed pattern, low levels were found in the morning and increased levels in the evening. Our studies clearly show that when determining parameters of the fibrinolytic system, the diurnal variations have to be taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

High-dose systemic streptokinase and acylated streptokinase-plasminogen complex (BRL 26921) in acute myocardial infarction: alterations of the fibrinolytic system and clearance of fibrinolytic activity.

We report the results of two consecutive studies using intravenous bolus injections of streptokinase (SK) or acylated plasminogen-SK complex (BRL 26921) in patients with acute myocardial infarction (AMI). In the first study, 20 patients received either 750,000 units (U) SK (group IA, n = 10) or 1,500,000 U SK (group IB, n = 10) within 5-10 min intravenously. In the second study 10 consecutive patients received 750,000 U SK within 15 min (group IIA) intravenously. The following 10 consecutive patients received 30 mg BRL 26921 within 2 min (group IIB). Early reperfusion was found in 16 patients in the first study (8 in each group) and in 18 patients in the second study (9 in each group). The decrease of fibrinolytic activity was biphasic with a half-disappearance time of 112.5 min for BRL 26921 and 31 (IA) and 18 (IB) min for SK. alpha 2-Antiplasmin depletion and a decrease of fibrinogen was observed with no differences after bolus injections of SK and of BRL 26921.

Aged↗
PubMed1987

Measurement of factor VIII procoagulant antigen in normal subjects and in hemophilia A patients by an immunoradiometric assay and by an enzyme-linked immunosorbent assay.

Factor VIII coagulant antigen (FVIII:Ag) and FVIII coagulant activity (FVIII:C) were measured in 102 healthy individuals, in 5 hemophilia A carriers and in 21 hemophilia A patients before and after infusion of heat-treated high-purity FVIII concentrates. Factor VIII:Ag was determined by a solid-phase micro enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies and by a conventional solid-phase immunoradiometric assay (IRMA). Factor VIII:C was assessed using a one-stage assay. The micro ELISA was decidedly more precise than the IRMA. There was a close correlation between the results obtained by the three assays in the plasma of healthy subjects and in hemophilia A carriers. After transfusion of FVIII concentrates to hemophilia A patients, the FVIII:Ag recoveries were significantly lower than the FVIII:C recoveries and the biological half-life of FVIII:Ag was significantly shorter than for FVIII:C. The calculated half-life of FVIII:C was longer than in any previous study.

Adolescent↗
PubMed1986

Factor VIII: C (FVIII: C) recovery and half-life after infusion of steam-treated high purity factor VIII concentrate in severe hemophilia A--comparison of one-stage assay, two-stage assay and a chromogenic substrate assay.

Factor VIII:C recovery and half-life was measured in 16 hemophilia A patients under comprehensively standardized conditions. Each patient received the same lot of a steam-treated high purity FVIII concentrate at a dose of 19-33 U/kg body weight. A comparison was made between the one-stage assay, the two-stage assay and a chromogenic substrate test for FVIII:C determination using a FXa-sensitive chromogenic substrate. Factor VIII:C potency of the administered FVIII concentrate was measured using calibration curves derived from a concentrate standard and FVIII:C plasma levels were read from calibration curves derived from a plasma standard. The chromogenic assay showed a good reproducibility at FVIII:C levels between 0.015 and 0.50 U/ml. The FVIII:C recoveries calculated from the results of the one-stage assay, the two-stage assay and the chromogenic substrate test were 109 +/- 20, 92 +/- 14 and 81 +/- 11% (mean +/- SD), respectively. The elimination half-lives of FVIII:C were calculated by non-linear least square analysis using a modified computerized Gauss-Newton algorithm. The half-lives calculated from the FVIII:C plasma levels measured by the one-stage assay, the two-stage assay and the chromogenic test were 23.8 +/- 6.4, 22.2 +/- 5.7 and 17.1 +/- 4.8 h (mean +/- SD), respectively. No previous study has reported such long half-life values. Our findings indicate that measurements of recoveries and half-lives by the chromogenic FVIII:C assay and by computerized non-linear least square analysis allow the possibility of individualized FVIII replacement therapy.

Adolescent↗
PubMed1986

Comparative study of intranasal, subcutaneous and intravenous administration of desamino-D-arginine vasopressin (DDAVP).

This study was performed to evaluate the influence of different routes of administration on the efficacy of DDAVP treatment. Ten healthy volunteers received DDAVP intranasally (i.n.), subcutaneously (s.c.) and intravenously (i.v.) in a randomized cross-over trial. Factor XII and high molecular weight (HMW)-kininogen levels increased only slightly after DDAVP administration. The mean increase of factor VIII: C was 3.1 (i.v.), 2.3 (s.c.), and 1.3 (i.n.) - fold over baseline. Ristocetin cofactor (von Willebrand factor antigen) increased 3.1 (2.5), 2.0 (2.3) and 1.2 (1.2) - fold over baseline mean values after i.v., s.c. and i.n. DDAVP, respectively. The half-disappearance time of factor VIII and von Willebrand factor (vWF) after DDAVP ranged from five (factor VIII:C) to eight hours (vWF). The mean increase of fibrinolytic activity was more pronounced after i.v. DDAVP. The antidiuretic effect was moderate with no apparent differences between the routes of application. This study provides further evidence that both i.v. and s.c. DDAVP administration result in an appropriate and reliable stimulation of haemostasis. An additional advantage of s.c. administration is its suitability for home treatment.

Adult↗
PubMed1985

Fibrinogen distribution on surfaces and in organelles of ADP stimulated human blood platelets.

The fibrinogen distribution in platelet organelles after ADP-stimulation was investigated with anti-human fibrinogen using protein A-gold applied to serial sections. Fibrinogen was detected in the so-called alpha-granules of platelets and also in granule protrusions which were observed after ADP-stimulation. The ends of these protrusions were formed as coated membranes and the tips were often in apposition to the surface connected membranes or the plasmalemma. At such places fusion events and hence signs of an exocytosis could be demonstrated by means of cryofixation and cryosubstitution. Examination of serial sections revealed fibrinogen on all these granule profiles. Surface connected membranes, free surfaces and the characteristic structure of the contact zones of aggregated platelets were also labelled by gold particles but less than anticipated. On the platelet surfaces and surface connected membranes fibrinogen was rarely demonstrable with ferritin-labelled anti-human fibrinogen on washed or thrombin-stimulated, almost fibrinogen free platelets. After addition of human fibrinogen to the thrombin stimulated and disaggregated platelets a part of the platelets aggregated spontaneously and formed characteristic contact zones. Anti-human fibrinogen was observed on the free surfaces, in filamentous bridges between the contact spaces and in a tubular surface connected membrane system with involvement of coated membranes at the central ends of these structures. The results indicate the following: all alpha-granules contain fibrinogen; after ADP-stimulation secretion takes place with involvement of coated membranes; during aggregation fibrinogen binds to platelet surfaces and forms contact spaces; fibrinogen is taken up by the surface connected system with involvement of coated membranes.

Adenosine Diphosphate↗