Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “THROMBOPLASTIN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMedDate not supplied

Viper venoms and coumarin-induced prothrombin. A comparison of several one-stage methods employing three different venoms as thromboplastins.

Three venoms obtained from three vipers, namely Echis carinatus, Notechis scutatus scutatus and Oxyuranus scutellatus, have been used as thromboplastin in a one-stage assay of coumarin-induced prothrombin. Regardless of the venom used, prothrombin resulted to be low in coumarin-treated patients. The mean values obtained were 27.2, 33.6, and 24.2%, respectively. These values were comparable to those obtained by means of the classical one-stage method (24.8%). A good correlation was observed among the different methods. However, the levels observed using the Notechis scutatus scutatus venom method were slightly higher as compared to those obtained by means of the other viper venoms and by means of the classical one-stage method. The three viper venoms used seem unable to activate coumarin-induced prothrombin. The levels obtained were in fact, in each instance, definitely lower than those observed immunologically. Methods which employ these viper venoms may be used in the evaluation of prothrombin in coumarin-treated patients.

Animals↗
PubMed2003

Activated clotting time or activated partial thromboplastin time as the method of choice for patients undergoing neuroradiological intervention.

We evaluated the role of the activated clotting time (ACT) and activated partial thromboplastin time (APTT), both currently available as bedside tests, for monitoring anticoagulation following bolus injection of 2500 or 5000 IU heparin in 21 patients undergoing neuroradiological procedures. APTT was measured using the CoaguChek Pro device compared to the laboratory standard measurement and ACT comparing CoaguChek Pro to Hemochron Celite and Kaolin. Statistical analysis was performed using Bablok-Passing regression. Despite heparin doses of 2500-5000 IU APTT measurements were out of range in 67% of patients using CoaguChek Pro and in 76.5% of patients using the laboratory measurement. ACT was reliably determined in all patients. The correlation between the different devices (CoaguChek Pro vs. Hemochron Celite r=0.69, Kaolin r=0.78) and assays (Hemochron Celite/Kaolin r=0.85) was good. ACT ranged from 141-417 s measured by CoaguChek Pro and 138-320 s measured by Hemochron Celite and 172-381 s using Hemochron Kaolin. These results indicate that ACT is the method of choice for monitoring anticoagulation in neuroangiographic procedures.

Female↗
PubMed1985

Novel factor X deficiency. Normal partial thromboplastin time and associated spindle cell thymoma.

This report presents a heretofore undescribed laboratory variant of congenital factor X deficiency, seen in conjunction with a relatively rare tumor. The patient had a history of bleeding, a prolonged prothrombin time, and a factor X value of 4.2 percent of normal activity, but the partial thromboplastin time and Russell's viper venom clotting time were normal. Management of this case required unusual measures to treat the patient's coagulopathy.

Blood Coagulation Tests↗
PubMed1990

Correlation between lupus anticoagulants and anticardiolipin antibodies in patients with prolonged activated partial thromboplastin times.

PURPOSE: An increased incidence of thrombosis has been reported in patients with a prolonged activated partial thromboplastin time (APTT) due to a lupus anticoagulant (LA), which is an antibody to negatively charged phospholipids. The antiphospholipid antibodies can be quantitated in an enzyme-linked immunoabsorbent assay (ELISA) that utilizes cardiolipin as the antigen. With the development of the ELISA, two major areas of controversy have arisen. First, the correlation between assay results for LA and for the ELISA has varied widely among laboratories. Second, some investigators have described a correlation between high levels of anticardiolipin antibodies (ACA) and thrombotic disorders, whereas others have found no association between ACA levels and thrombosis in a general population of medical patients. To explore these issues further, the present study determined the sensitivity and specificity of an LA assay for detecting ACA in medical patients with a prolonged APTT. The association between the isotype and titer of ACA and thrombosis was examined in those patients positive for LA. PATIENTS AND METHODS: Plasma samples from 70 medical patients with a prolonged APTT by routine screening studies were tested for the presence of LA by dilution of phospholipid in an APTT system and for IgM and IgG ACA according to a standardized ELISA. Clinical records were reviewed for a history of thrombotic events by an investigator who had no knowledge of the laboratory results. RESULTS: The ACA assay gave positive results in 47 patients, 44 of whom also tested positive for LA. Thus, the sensitivity for the LA assay for detecting ACA was 94% (confidence interval, 82% to 99%). The result of the LA assay was negative in 20 of 23 patients who were ACA-negative. The specificity of the LA assay was 87% (confidence interval, 67% to 98%). Twelve of the 47 patients (26%) had a history of venous or arterial thrombosis. Of these patients, 75% tested in the high-positive range for IgG or IgM ACA, or both. Of the 35 patients without thrombosis, only 14% were in this range. Patients with thrombosis had either underlying systemic lupus erythematosus, lymphoma, or no apparent etiology for LA. There was no history of thrombosis in patients with LA associated with infection or medication. CONCLUSION: A test for LA in medical patients with a prolonged APTT can be sensitive and specific for ACA. Determination of ACA levels in patients who have LA that is not induced by medication or infection may define those patients at increased risk for thrombosis.

Adult↗
PubMed1982

A modified activated partial thromboplastin time with the use of amniotic fluid. Preliminary report of a new technique for detection of fetal lung maturity.

The need for a simple, accurate, rapidly performed fetal lung maturity test remains unfilled despite the large number of methods available. In a preliminary prospective study, the amniotic fluid activated partial thromboplastin time (PTT) appeared to be encouraging. The false mature rate in an at-risk patient population was 0.80%, and the false immature rate was 61%. The false mature rates for the lecitin/sphingomyelin ratio and absorbance 650 in the same patients were 0% and 0.63%, respectively, whereas the false immature rates were 81.8% and 91.3%. Since both the amniotic fluid activated PTT and absorbance 650 can be readily performed in the smallest hospital, the accuracy of the combination was explored. Combining the amniotic fluid activated PTT with a mature absorbance 650 reduced the false immature rate to 30.7%. Th amniotic fluid activated PTT is a rapid, accurate, economical test that is unaffected by gross blood or meconium contaminants.

Amniotic Fluid↗
PubMed1978

Effects of acidic glycosaminoglycans in human aortic inner and outer layers on partial thromboplastin time.

(1) Acidic glycosaminoglycans (AGAG) were prepared from the inner and outer layers of human aorta and fractionated by Dowex 1-X2 columns. The anticoagulant activity of the fractionated AGAG was measured by the partial thromboplastin time. (2) Heparan sulfates were the main AGAG in the 1.25 M NaCl fraction and were more abundant in the outer layer than in the inner. Likewise, there was more dermatan sulfate in the outer layer. (3) The AGAG in the outer layer showed much greater anticoagulant activity than those in the inner layer, both in the 1.25 M and 1.75 M NaCl fractions. (4) Anticoagulant activity was attributed to the heparan sulfates in the 1.25 M fraction and to the dermatan sulfate in the 1.75 M fraction.

Aged↗
PubMed1983

Inflammatory particles stimulate thromboplastin production by human monocytes.

Several inflammatory particles (zymosan, two forms of asbestos, carrageenan) and the soluble inflammatory agent dextran sulphate induced a dose- and time-dependent increase in thromboplastin activity of cultured human monocytes. Two weakly inflammatory particles (latex and anatase) had little effect. The increase largely depended on protein synthesis; was slow, reaching a peak at about 18 h; and was not due to endotoxin. This procoagulant may contribute to the fibrin deposition frequently seen in inflammatory lesions.

Asbestos↗
PubMed1984

Prolonged activated partial thromboplastin time and deficiency of high molecular weight kininogen in brown Norway rat mutant (Katholiek strain).

Activated partial thromboplastin time (APTT) was examined in Brown Norway (B/N) Katholiek rat, which was previously reported as high molecular weight kininogen deficient. APTT of B/N Katholiek was prolonged to 35 sec in comparison with B/N Kitasato and SD rat, showing APTT of 22-24 sec. The mixture of B/N Katholiek plasma and B/N Kitasato plasma (1:1) showed normal APTT value. B/N Katholiek plasma corrected the abnormally prolonged human coagulation factor deficient plasmas, such as XI, XII and prekallikrein deficient plasmas, while it did not correct the APTT of HMW kininogen deficient, Fitzgerald plasma. Intravenous injection of bromelain, which was previously reported to produce prolonged hypotension through the activation of factor XII to release bradykinin, induced slight effect in Katholiek rat, while in Kitasato rat it showed prolonged hypotension in similar degree as SD rat. Contents of coagulation factors in B/N Katholiek thus measured as well as the values of prekallikrein and HMW kininogen previously reported were summarized and suggested that B/N Katholiek rat could be similar deficiency as Fitzgerald trait.

Animals↗
PubMed1986

In vitro neutralization of heparin in plasma prior to the activated partial thromboplastin time test: an assessment of four heparin antagonists and two anion exchange resins.

This study was carried out to investigate the effects on the activated partial thromboplastin time test (APTT) when heparin in plasma was neutralized with protamine, Polybrene(R), poly-DL-lysine, or heparin neutralizing activity (HNA) extracted from platelets; or removed by means of the anion exchange resins TEAE cellulose or ECTEOLA cellulose. The effect on the APTT of adding the polycations protamine, Polybrene or poly-DL-lysine to citrated plasma was examined. The formation of heparin/polycation complexes was studied by means of their light scattering properties. The low yields of platelet HNA obtained excluded this from practical use as an in vitro heparin antagonist. ECTEOLA cellulose was unable to remove plasma heparin at levels as low as 1 U/ml by the technique employed. TEAE cellulose was able to efficiently remove at least 40 U of heparin from 1 ml of plasma but also caused a non-specific prolongation of the APTT. The polycations protamine, Polybrene, and poly-DL-lysine, possessed clot promoting activity at low concentrations and acted as anticoagulants in their own right at higher concentrations. At a plasma heparin concentration of 4 U/ml, protamine was the most efficient neutralizer of heparin, while at 10 U/ml, Polybrene was the most effective in this respect. It was concluded that care must be taken in the interpretation of the APTT after heparin neutralization or removal as heparin antagonist induced non-specific effects may be present.

Anion Exchange Resins↗
PubMed1987

New modified activated partial thromboplastin time and prothrombin time methods using a synthetic chromogenic substrate in combination with diazotization.

A chromogenic substrate, H-D-Phe-Pip-Arg-pNA (S-2238) is a highly specific substrate to thrombin and releases p-nitroaniline (pNA) by the action of thrombin. We describe new modified APTT and PT methods using S-2238 in combination with the diazotization of pNA. In the modified APTT method, 100 microliter citrated plasma (diluted to 10-fold), 90 microliter 1 mM S-2238, 100 microliter 20 mM CaCl2 and 100 microliter Actin were mixed in an ice-bath, then incubated for 8 min at 37 degrees C. The reaction was stopped, and the generated pNA was diazotized by adding the following solutions sequentially: 975 microliter 0.04% sodium nitrite, 975 microliter 0.3% ammonium sulfamate and 975 microliter 0.07% N-(l-naphthyl)-ethylenediamine dihydrochloride. Diazotization changed pNA from yellow to pink. Then, absorbance at 545 nm was read, and values were expressed as thrombin units/ml plasma. In the modified PT method, 100 microliter citrated plasma (diluted to 20-fold), 90 microliter 1 mM S-2238 and 200 microliter tissue thromboplastin-C solution were mixed and processed as above. Correlations of the present modified APTT and APTT methods, and of modified PT and PT methods were significant (r = 0.426, p less than 0.01 and r = 0.561, p less than 0.01, respectively).

Aniline Compounds↗
PubMed1990

The effect of fluorescent humic substances existing in the well water of Blackfoot disease endemic areas in Taiwan on prothrombin time and activated partial thromboplastin time in vitro.

Fluorescent humic substances (FHS) in well water of Blackfoot disease endemic areas were purified and fractionated by Sephadex G-25 column chromatography. Four fractions of the purified FHS were isolated. The purified FHS and their fractions were then added to normal human pool plasma in vitro separately to detect the abilities of the effects on prothrombin time (PT) and activated thromboplastin time (APTT). Results showed that all of the four fractions of the purified FHS prolonged both PT and APTT in the higher concentration ranges (10 mg/ml - 20 mg/ml), but shortened both PT and APTT in the lower concentration ranges (0.5 mg/ml - 5 mg/ml). Among the four fractions of the FHS, the fraction 1, the humic substance with the highest molecular weight among all the four FHS, showed the most obvious effects. Owing to the effects of the FHS on PT and APTT values, we supposed that there is a close relationship between the FHS and the cause of Blackfoot disease.

Arsenic↗
PubMed1991

Generation of procoagulant (thromboplastin) and plasminogen activator activities in peripheral blood monocytes after total hip replacement surgery. Effects of high doses of corticosteroids.

Development of thromboplastin (tpl) and plasminogen activator (PA) activity in monocytes and the effects of high doses of corticosteroids (HCD) on these activities were studied in patients undergoing a standardized surgical trauma. Twelve patients who received uncemented total hip prostheses were divided into a nonsteroid group (n = 6) and a steroid group (n = 6). We found no significant differences between the two patient groups regarding tpl or PA activities of peripheral blood mononuclear cells (PBM) isolated during the postoperative phase. However, in the nonsteroid group there was a tendency for increased expression of procoagulant activity and decreased fibrinolytic activity on the 1st postoperative day, favoring the formation of fibrin in the monocyte microenvironment. Further, PBM isolated on the 1st and 2nd day after surgery were significantly less capable of generating tpl activity on endotoxin stimulation than cells isolated preoperatively. This was not the case in the steroid group. These patients had also a tendency for decreased fibrinolysis at the end of the 1st postoperative week, indicating increased imbalance towards a more thrombotic stage after surgery.

Adrenal Cortex Hormones↗
PubMed1991

The influence of time, temperature and packed cell on activated partial thromboplastin time and prothrombin time.

Activated partial thromboplastin time (APTT) and prothrombin time (PT) were performed in four groups of studies in order to evaluate the influences of time, temperature, and different forms of plasma storage to the result. Different designs for storage of the plasmas were studied, including the plasmas stored either with or without packed cells, the plasmas stored in the cuvette with exact volume for performing the test or in the test tube. The temperatures for store of the plasma were at room temperature, at 4 degrees C and at -70 degrees C. The time for store of the plasma was from 1 hour up to 7 hours. The plasmas included normal pooled plasmas and diseased plasmas. From this study, it is found that the PT test was not easily affected by the temperature, storage time and the form of storage in comparison with the APTT test which was much easily affected by the above conditions. APTT should be done within 2 hours after sampling and the plasma should be stored with the packed cells at 4 degrees C in order to obtain a reliable result. PT could be done within 7 hours without influence to the result if the plasma was stored with the packed cells at 4 degrees C. No significant cold-induced shortening of PT could be noted when the plasma was incubated at 4 degrees C up to 7 hours. In either PT or APTT, the most suitable condition for storing the plasma should be with the packed cells at 4 degrees C.

Blood Preservation↗
PubMed1983

Alterations in the apparent tissue factor (thromboplastin) expression in HeLa cells by a cellular factor Xa inhibitor.

HeLa cells have undetectable tissue factor (thromboplastin) activity when measured by a one-stage coagulation assay. In contrast, these cells accelerated the factor VII-catalyzed cleavage of factor X. The two assays gave similar results after either heating the samples to 100 degrees C for 2 min or exposure to thrombin. Neither of these treatments altered the tissue factor activity of human foreskin fibroblasts, a cell type with high tissue factor activity. HeLa cells contain an inhibitor(s) directed against factor Xa but not thrombin. The inhibitor(s) was inactivated by exposure to thrombin or by heat treatment. Inhibition of factor Xa-catalyzed cleavage of a synthetic peptide was blocked by ethyleneglycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) so the inhibition was apparently dependent on divalent cations. Inhibition was not accelerated by heparin. The inhibitor(s) was not protein C or other serine proteases since it was not inactivated by diisopropylfluorophosphate. The factor Xa inhibitor(s) has been isolated from HeLa cells with an approximate 500-fold increase in specific activity. After SDS-polyacrylamide gel electrophoresis factor Xa-inhibitory activity was recovered from a region corresponding to the major Coomassie-staining band at 43 kDa and in lesser amounts from regions corresponding to 26 and 17 kDa. Cellular inhibitors of coagulation may partially explain the low apparent tissue factor observed in some in vitro cells and may serve a regulatory role in limiting the expression of tissue factor.

Cells, Cultured↗
PubMed1993

Intraoperative measurement of activated partial thromboplastin time and prothrombin time by a portable laser photometer in patients following cardiopulmonary bypass.

Intraoperative capabilities to rapidly assess coagulation status following cardiopulmonary bypass (CPB) may be of benefit in providing optimal hemostasis and transfusion management, because CPB causes abnormalities in coagulation that may increase morbidity and mortality. The Ciba Corning 512 coagulation monitor (Ciba Corning, Medfield, MA) is a compact and portable device that rapidly determines the prothrombin time (PT) and activated partial thromboplastin time (APTT) in whole blood samples. One hundred patients requiring CPB had APTT and PT determined in whole blood specimens by the 512 coagulation monitor and in plasma specimens by the hospital laboratory from the same arterial blood sample obtained after protamine administration. Correlation coefficients of 0.95 and 0.77 were obtained for the paired APTT and PT tests, respectively (P < 0.01). A bias of 12.6 seconds and 0.77 seconds was determined for the APTT and PT, respectively. The 95% confidence intervals of the bias of the APTT and PT were 9.7 seconds to 15.5 seconds and 0.3 seconds to 1.16 seconds, respectively. The 512 coagulation monitor provided APTT and PT results in less than 3 minutes compared to approximately 45 minutes for the hospital laboratory. A reduction in accuracy was associated with the 512 coagulation monitor PT and APTT when different sampling sites were used. The 512 coagulation monitor accuracy was not affected by a variation of hemoglobin concentration or platelet count between 6 and 12 gm/dL and 15 to 300 x 10(9)/L, respectively. In conclusion, the 512 coagulation monitor provided a rapid APTT and PT result, but the APTT was less accurate. Speeding access to hospital laboratory results would be even more efficacious and accurate.

Adult↗
PubMedDate not supplied

Overuse of prothrombin and partial thromboplastin coagulation tests in medical inpatients.

INTRODUCTION: In the monitoring of anticoagulant therapy, prothrombin time (PT) is used to measure the effect of warfarin, whereas the partial thromboplastin time (PTT) measures the therapeutic effect of unfractionated heparin. Low molecular weight heparin (LMWH) does not require routine monitoring. OBJECTIVE: We collected data on the frequency of simultaneous PT and PTT requests, where only one or neither is indicated, and estimated the potential cost savings if ordering was appropriate. METHODS: The study was performed at Nassau University Medical Center, a major teaching institution in East Meadow, New York. Inpatient charts were reviewed consecutively until 50 patients prescribed warfarin alone, intravenous heparin alone, or LMWH alone were selected. We then determined which coagulation tests were performed each day for these patients by review of their computerized laboratory results. The costs of laboratory tests were obtained from the hospital laboratory and were used to calculate potential savings. RESULTS: PT and PTT coagulation tests were requested together in all 50 patients. Seventeen patients on LMWH alone had 30 sets of PT/PTT performed (60 tests). Seventeen patients on intravenous heparin had 87 PTs performed. Twelve patients on warfarin had 60 PTTs performed. In total, 232 unneeded PT or PTTs were ordered in these 50 patients, or 4.6 per patient during hospitalization. CONCLUSION: The review of the records of 50 medical inpatients found that PT and PTT were invariably requested together, despite a lack of indication. The 50 patients incurred a total of $2434 in unneeded costs. If representative of common clinical practice, significant cost savings may be possible. Education, computerization, and information on costs of individual tests may reduce unneeded investigations.

Anticoagulants↗
PubMed2005

Antiphospholipid antibodies in pediatric patients with prolonged activated partial thromboplastin time during infection.

OBJECTIVE: To investigate the close association between different antiphospholipid antibodies (aPL) caused by infection and their appearance together with a prolonged activated partial thromboplastin time (aPTT). METHODS: Sera from 122 children were evaluated in this study. Thirty-seven children with mild to medium prolonged aPTT (>37.2s) and elevated C-reactive protein (CRP) levels during various forms of infections (group 2), 18 children without infections (group 3) but with mild to medium prolonged aPTT and 13 children with infections (group 4) and with elevated CRP-level as well as a control group (group 1) of 54 patients without any infection and normal aPTT and negative CRP levels were investigated with commercially available ELISA tests (AESKU.Diagnostics, Wendelsheim, Germany) for the presence of antibodies directed against cardiolipin (CL), phosphatidylserine (PS) and beta2-glycoprotein I (beta 2GPI). The cutoff for positive results was defined with the healthy, aged matched control group (group 1) using the mean OD values plus 2 standard deviations. The lupus anticoagulant (dilute Russell's Viper Venom time, dRVVT) and coagulation Factor XII were determined with routine tests (Dade Behring). RESULTS: Detection of at least one antibody to phospholipids was possible in 89.2% of group 2. It could be shown that IgM anti-beta 2GPI antibodies were found in 27 (59.5%) of group 2, but only in 1 (5.6%) of group 3 (p=0.024) and only in 4 (7.4%) of the controls (p=0.014). The presence of IgG-anti-beta 2GPI antibodies showed no significant difference in the different groups. Furthermore, children of groups 2, 3 and 4 had statistically significant higher levels of antibodies against PS IgG and PS IgM than controls. Also, antibodies to CL of the IgG-type were more frequently detected in children of group 2 than in controls (p=0.038). Detection of CL-IgM antibodies did not reach a significant level in the comparison of the different groups. CONCLUSION: During commonly acquired infections elevation of aPL of nearly all types seems to be a common process. Mild prolongation of aPTT might reflect this presence of aPL in the course of the infectious disease. Our data suggest that there exists no differences in specificity in comparison to the "pathogenic" aPL but the presence over time might be the trigger for the autoimmune activity to begin.

Adolescent↗