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Modulation of urokinase-type plasminogen activator and metalloproteinase activities in cultured mouse mammary-carcinoma cells: enhancement by paclitaxel and inhibition by nocodazole.

Paclitaxel is a potent anti-tumor drug used in the treatment of breast cancer. It induces de-centralization of the microtubular system in tumor cells, blocking cell division. In the search for dissemination to a secondary site, cancer cells are capable of degrading most components of the extracellular matrix via an extracellular proteolytic cascade, including urokinase-type plasminogen activator (uPA) and the matrix metalloproteinases (MMPs). In the present study, the effects of paclitaxel and nocodazole, 2 drugs known to affect microtubules with opposite mechanisms of action, have been tested for their effect on the secretion of uPA and MMPs in cultures of F3II mouse mammary-tumor cells. Tumor-derived uPA activity significantly increased after pre-treatment of tumor cells for 24 hr with micromolar concentrations of paclitaxel (4 microM), while decreasing after pre-treatment with nocodazole (1 microM). A similar modulation was found for MMP-9 by zymographic analysis. Immunofluorescence and Western-blot analysis confirmed the formation of parallel microtubule fragments in paclitaxel-treated cells and almost complete de-polymerization of microtubules in nocodazole-treated ones. Our data suggest that, through opposite actions on microtubule organization and dynamics, paclitaxel and nocodazole exert inverse modulation of tumor-derived proteolytic activity in mammary tumor cells.

Animals↗

Cortisol suppression by dexamethasone in the healthy elderly: effects of age, dexamethasone levels, and cognitive function.

The effects of age, cognitive function (measured by Cambridge cognitive examination (CAM-COG) score); and dexamethasone (DEX) levels on the dexamethasone suppression test were studied in 33 healthy older subjects (age 51-96). Three subjects (9.1%) were nonsuppressors and were older and had lower CAMCOG scores than the 30 suppressors. Significant correlations were observed between natural log-transformed postdexamethasone cortisol (LNCOR) levels and age (r = 0.40) and CAMCOG score (r = -0.45). Multiple regression analysis was used to investigate the relationship between LNCOR, age, DEX levels, and CAMCOG score. Age and DEX combined explained 41% of the variance in LNCOR values, whereas CAMCOG score and DEX levels explained 44% variance. As age and CAMCOG were highly correlated (r = -0.72), both together did not significantly improve the fit of regression equation (47% variance explained). These findings suggest an association between advancing age, impaired glucocorticoid feedback, and cognitive dysfunction in healthy human subjects. Although any causal connection remains to be demonstrated, results would be consistent with the "glucocorticoid cascade" hypothesis of human aging.

Aged↗

Effect of intrathecally administered local anesthetics on protein phosphorylation in the spinal cord.

To elucidate the biochemical mechanisms of spinal anesthesia, we studied the effects of procaine and tetracaine on protein phosphorylation in the mouse spinal cord. Mice were injected intrathecally with either procaine, tetracaine (67 mM/approximately 2%, 10 microL, N = 5/drug), or saline (N = 4/group). Five minutes after injection, animals were killed with a guillotine, and the spinal cord was removed. The caudal 3-cm cord segment was homogenized and centrifuged, and an aliquot of the supernatant was used for phosphorylation assays. Calcium-dependent phosphorylation was initiated by incubating the samples in buffer containing [gamma-32P]ATP at 37 degrees for 30 min. The proteins were electrophoresed using slab gel and two-dimensional electrophoresis, and phosphorylated proteins were visualized by autoradiography. The data demonstrated that spinal anesthesia changes the phosphorylation state of five endogenous substrate proteins with apparent molecular masses of 130 (protein-a), 105 (protein-b), 55 (protein-c), 47 (protein-d), and 33 (protein-e) kDa. In two-dimensional electrophoresis, protein-a resolved into two proteins (a1 and a2). Analysis of variance of the densitometric data suggested a significant effect for the treatment (F(2,16) 735, P < 0.00005). Post hoc comparisons with the saline-treated controls, using the Newman-Keuls test, indicated that local anesthetics significantly affected phosphoproteins (P < 0.05) except for protein-al in the tetracaine-treated group. Further characterization of these phosphoproteins should aid in determining their role in the signal transduction cascade affected by spinal anesthesia.

Anesthetics, Local↗

The targets of the lytic antibody response against Trypanosoma cruzi.

Trypanosoma cruzi trypomastigotes, but not epimastigotes, are normally resistant to the lytic effects of complement from vertebrate hosts susceptible to infection. This resistance facilitates parasite survival and infectivity. During the course of chronic infections, however, the vertebrate hosts produce antibodies that render the trypomastigotes sensitive to lysis, primarily via the alternative complement cascade and amplified by the classical pathway. Here, Greice Krautz, Jessica Kissinger and Antoniana Krettli summarize research on lytic antibodies, and on their respective target(s) on the T. cruzi surface. These targets are useful in tests aimed at the diagnosis of chronic Chagas disease for control of cure after specific treatment and for vaccine development.

Animals↗

Cascade summing corrections for HPGe spectrometers by the Monte Carlo method.

Cascade summing corrections for application in HPGe gamma ray spectrometry have been calculated numerically by the Monte Carlo method. An algorithm has been developed which follows the path in the decay scheme from the starting state at the precursor radionuclide decay level, down to the ground state of the daughter radionuclide. With this procedure, it was possible to calculate the cascade summing correction for all gamma ray transitions present in the decay scheme. Since the cascade correction requires the values of peak and total detection efficiencies, another code has been developed in order to estimate these parameters for point and cylindrical sources. The radionuclides 60Co, 133Ba and 131I were used for testing the procedure. The results were in good agreement with values in the literature.

Journal Article↗

Core mutations that promote the calcium-induced allosteric transition of bovine recoverin.

Recoverin is a small calcium binding protein involved in regulation of the phototransduction cascade in retinal rod cells. It functions as a calcium sensor by undergoing a cooperative, ligand-dependent conformational change, resulting in the extrusion of the N-terminal myristoyl group from a hydrophobic pocket. To test the role of certain core residues in tuning this allosteric switch, we have made and characterized two mutants: W31K, which replaces Trp31 with Lys; and a double mutant, I52A/Y53A, in which Ile52 and Tyr53 are both replaced by Ala. These mutations decrease the hydrophobicity of the myristoyl binding pocket. They are thus expected to make sequestering of the myristoyl group less favorable and destabilize the Ca2+-free state. As predicted, the myristoylated forms of the mutants exhibit increased affinity for Ca2+, whether monitored by equilibrium binding of 45Ca2+ (Kd = 17.2, 7.9, and 8.1 microM for wild type, W31K, and I52A/Y53A, respectively) or by the change in tryptophan fluorescence associated with the conformational change (Kd = 17.9, 3.6, and 4.4 microM for wild type, W31K, and I52A/Y53A, respectively). The mutants also exhibit decreased cooperativity of binding (Hill coefficient = 1.2 and 1.0 for W31K and I52A/Y53A vs 1. 4 for wild type). Binding of the mutant proteins to rod outer segment membranes occurs at lower Ca2+ concentrations compared to wild-type protein (K1/2 = 5.6, 2.2, and 1.0 microM for wild type, W31K, and I52A/Y53A, respectively). The unmyristoylated forms of the mutants exhibit biphasic Ca2+ binding curves, nearly identical to that observed for wild type. The binding data for the two mutants can be explained by a concerted allosteric model in which the mutations affect only the equilibrium constant L between the two allosteric forms, T (the Ca2+-free form) and R (the Ca2+-bound form), without affecting the intrinsic binding constants for the two Ca2+ sites. Two-dimensional NMR spectra of the Ca2+-free forms of the mutants have been compared to the wild-type spectrum, whose peaks have been assigned to specific residues (1). Many resonances assigned to residues in the C-terminal domain (residues 100-202) in the wild-type spectrum are identical in the mutant spectra, suggesting that the backbone structure of the C-terminal domain is probably unchanged in both mutants. The N-terminal domain, in which both mutations are located, reveals in each case numerous changes of undetermined spatial extent.

Allosteric Site↗

Ultra-rapid multicolor PRINS protocol for chromosome detection in human sperm.

We report a new multicolor PRINS procedure for chromosome identification on human sperm. Based on the direct in-situ mixing of the colors of the fluorochromes (FITC, TRITC, Cascade Blue) incorporated in sequential PRINS reactions, this method facilitates rapid distinct labeling of 3 or 4 chromosomes. Each PRINS reaction consists of a unique 4 minute step for annealing and elongation. The method was successfully tested on lymphocytes and spermatozoa. Estimates of disomy were performed for chromosomes 7, 9 and 16 on sperm samples from 2 healthy donors. There was no significant difference between the disomy rates obtained with the conventional two-color PRINS technique and this new three-color procedure. By simplifying the multicolor PRINS protocol, this new protocol should facilitate the use and adaptation of PRINS to various cytogenetic applications.

Chromosomes, Human, Pair 16↗

[Blood coagulation in normotensives and hypertensives in relation to their body mass index].

UNLABELLED: BACKGROUND AND PERSPECTIVE: Various parameters of the coagulation cascade and fibrinolysis are important predictors of myocardial infarction and stroke, for which hypertension is a risk factor. It is unclear whether an elevated blood pressure by itself can produce activated clotting. PATIENTS AND METHODS: Coagulation tests were done on overweight hypertensive (n=40); aged 49 +/- 8 years; group 3), overweight normotensives (n=19; aged 51 +/- 8 years; group 2) and normal-weight normotensives (n=20; aged 51 +/- 8; group 1). RESULTS: Plasminogen-activator-inhibitor 1 (PAI-1), a measure of impaired fibrinolysis, was elevated in group 2 (20.5 +/- 11 U/ml; p < 0.001), compared with group 1 (11.6 +/- 6 U/ml), and was even higher in group 3 (27.5 +/- 9 U/ml; p < 0.05). Fibrinogen and factor VIII, parameters that promote clotting, were elevated in group 2 (360 +/- 61 mg/dl and 143 +/- 15 %, respectively; p < 0.001), and in group 3 (368 +/- 63 mg/dl and 146 +/- 18%; p < 0.001) compared to group 1 (304 +/- 40 mg/dl and 127 +/- 17%). Correspondingly, fibrin monometers, a measure of intravascular coagulation, were elevated in group 3 (p < 0.05) and partial thromboplastin time (PTT) decreased (p < 0.001). Pearson correlation showed a significant (p < 0.001) positive relationship between PAI-1 and body mass index (BMI) (0.539), triglycerides (0.512), blood pressure (0.388 to 0.534), fibrinogen (0.404, and a negative one with HDL-cholesterol (0.625). BMI also correlated with fibrinogen (0.509; p < 0.001) and factor VIII (0.337; p < 0.01). CONCLUSIONS: Fibrinolysis and activated coagulation are reduced in hypertensive subjects: this favours the occurrence of myocardial infarction and stroke. In addition to the level of blood pressure, the extent of the changes are effected especially by BMI and metabolic risk factors.

Adult↗

Disseminated intravascular coagulation.

This review encompasses a description of the main pathophysiological events leading to disseminated intravascular coagulation (DIC). Emphasis has been put on microcirculatory disturbances and endothelial dysfunction. The normal hemostatic functions of the vascular endothelium are described. The close connection between endothelium and superimposed immuno-modulators is stressed as is the interrelation between the proteolytic cascade systems in the blood. The importance of differentiating local and systemic events is discussed. Organ dysfunction in multiple organ failure (MOF) is exemplified by pulmonary insufficiency in the adult respiratory distress syndrome (ARDS). Essential laboratory tests of DIC are described as are the cornerstones of treatment.

Disseminated Intravascular Coagulation↗

Selectin blockade plus therapy with low-dose sirolimus and cyclosporin a prevent brain death-induced renal allograft dysfunction.

Both antigen-dependent and -independent factors influence long-term organ allograft function and survival. Brain death (BD), a significant antigen-independent, donor-related injury upregulates a variety of inflammatory mediators in peripheral organs. One of the earliest responses to such an insult is the expression of selectins by endothelial cells of the transplanted tissues; these in turn trigger a cascade of nonspecific events, that enhance host alloresponses and which may be worsened by toxic effects of long-term immunosuppression. Using a rat model in which donor BD accentuates subsequent renal allograft injury, we have tested the effects of therapy with recombinant P-selectin glycoprotein ligand (rPSGL-Ig) alone, or in combination with sirolimus (SRL) and cyclosporin A. We found that in contrast to the effects of standard doses of SRL or cyclosporine, rPSGL-Ig decreased inflammation in the early posttransplant period such that lower doses of maintenance immunosuppression were sufficient to maintain long-term graft function.

Animals↗

Activation of interferon-stimulated response element in huh-7 cells replicating hepatitis C virus subgenomic RNA.

Interferon-alpha (IFN(alpha)) binds to receptors on the cell surface, which initiate a cascade of signal transduction pathways that leads to transcription of selected genes. This transduction pathway involves binding of transcription factors to a common cis-acting DNA sequence called IFN-stimulated response element (ISRE). To test whether these signaling pathways are functional in hepatitis C virus (HCV)-replicating cells, we studied the regulation of ISRE-mediated transcription of firefly luciferase gene in stable replicon cell lines. A plasmid construct was prepared (pISRELuc) which contains four tandem repeats of 9-27 ISRE sequences positioned directly upstream of the herpes virus 1 thymidine kinase promoter TATA box that drives the expression of firefly luciferase. Regulation of ISRE-mediated expression of firefly luciferase by IFN(alpha) was studied by transfecting this clone into Huh-7 cells replicating HCV subgenomic HCV RNA. The significance of ISRE-mediated transcriptional activation was studied in a replicon cell line by pretreatment of cells with actinomycin D, which inhibits cellular DNA-dependent RNA transcription. IFN treatment activates ISRE-mediated expression of luciferase, indicating that this pathway is functional in Huh-7 cells. Activation of ISRE-mediated transcription of luciferase is relatively high in two Huh-7 stable cell lines replicating HCV subgenomic RNA. Inhibition of ISRE-mediated transcription of luciferase by actinomycin D also makes HCV replication totally resistant to IFN(alpha). These in vitro studies suggest that activation of IFN-inducible genes is important in mounting a successful antiviral response against HCV.

Cell Line, Tumor↗

Induction of apoptosis by disturbing mitochondrial-membrane potential and cleaving PARP in Jurkat T cells through treatment with acetoxyscirpenol mycotoxins.

Paecilomyces tenuipes is a famous Chinese medicinal entomopathogenic fungus that grows within the larvae of silkworms. 4beta-acetoxyscirpendiol (4-MAS), a cytotoxic compound belonging to the scirpenol subfamily of trichothecene mycotoxin, was isolated from Paecilomyces tenuipes. To further elucidate the cytotoxic mechanism of 4-MAS, evidences of its induction of apoptosis, together with the structurally related acetoxyscirpenol moiety mycotoxins (ASMs) such as, 15-acetoxyscirpenol (15-MAS), 4,15-diacetoxyscirpenol (4,15-DAS), and 3alpha-acetyldiacetoxyscirpenol (TAS), in the human Jurkat T cell line were reported herein. In the MTT reduction and time-course cytotoxicity assays for monitoring cell viability, all the four ASMs that were tested exhibited cytotoxicity; single acetoxylation at C-4 of the scirpenol family resulted in relatively weak cytotoxicity, while acetoxylation at C-15 resulted in strong cytotoxicity regardless of the other acetoxylations at the C-3 and/or C-4 positions. Phosphatidylserine externalization was induced by all the ASMs that were treated at an early phase in a time-dependent manner, showing a typical apoptotic phenomenon, not a necrotic one. The ASMs also reduced the mitochondria's inner-membrane potential (deltaPsim) through flow cytometry analysis after staining these with DiOC6, a mitochondria-specific and voltage-dependent dye. Acetoxylation of ASM at C-15 increased deltaPsim disruption, but that at C-3 reduced the deltaPsim. The ASMs that were tested also cleaved 113 kDa PARP to an 89-kDa fragment through Western blot assay, suggesting the activation of caspase-3 and/or caspase-7 in the Jurkat T cell. DNA fragmentation was also observed to have been increased in a time-dependent manner by the ASMs that were tested in Jurkat T cells, resulting in the DNA fragmentation intensity order of 4,15-DAS>15-MAS>TAS>4-MAS. These data indicate that the Jurkat T cells that were treated with ASMs underwent typical cascades of apoptotic cell death.

Animals↗

In vitro performance characteristics of valved holding chamber and spacer devices with a fluticasone metered-dose inhaler.

STUDY OBJECTIVE: To compare the in vitro aerosol deposition characteristics of several commercially available valved holding chamber (VHC) and spacer devices used with a fluticasone metered-dose inhaler (MDI). DESIGN: In vitro aerosol deposition study SETTING: University-affiliated research center. DEVICES: Seven VHC devices: BreatheRite, E-Z Spacer, EasiVent, AeroChamber, InspirEase, OptiChamber, and Space Chamber. Six spacer devices: OptiHaler, Aerosol Cloud Enhancer (ACE), Gentle-Haler, MediSpacer, Ellipse, and a 6-inch tube (1-inch inside diameter). INTERVENTION: The respirable dose (aerosol particles 1-5 microm) of fluticasone was determined by sampling 10 220-microg actuations from five runs with each spacer or VHC plus MDI combination, by using a well-established in vitro cascade impactor method. MEASUREMENTS AND MAIN RESULTS: Fluticasone aerosol was washed from the impactor with methanol and quantified by means of high-performance liquid chromatography. Differences among outcomes were determined with analysis-of-variance testing. Among spacers, Ellipse had the highest respirable dose (104 microg, p < 0.01). Respirable doses for the 6-inch tube (74.3 microg), Gentle-Haler (81.7 microg), and MediSpacer (82.6 microg) were no different from that of the MDI (p > 0.05), whereas respirable doses of OptiHaler (44.6 microg) and ACE (47.2 microg) were less than those of all other spacers (p < 0.001). Among VHC devices, respirable doses from EasiVent (35.6 microg), AeroChamber (47.0 microg), InspirEase (52.7 microg), OptiChamber (53.1 microg), and Space Chamber (58.3 microg) were not different (p > 0.05), whereas BreatheRite (13.1 microg) and E-Z Spacer (27.3 microg) respirable doses were less than those of the other VHC devices (p < 0.05). CONCLUSION: Spacers and VHC devices available in the United States do not demonstrate equivalent in vitro performance with the fluticasone MDI. The difference between highest and lowest respirable doses in each device category would likely lead to clinically relevant differences in the quantity of fluticasone delivered to a patient.

Aerosols↗

Signaling pathways initiated in macrophages after engagement of type A scavenger receptors.

Scavenger receptors are macrophage cell surface molecules associated with endocytic uptake of lipoproteins and binding of microbial ligands. Macrophage class A scavenger receptors (SR-As) interact with ligands to induce cellular signaling leading to gene transcription and cytokine release. We used inhibitors of early and late signaling to block SR-A-mediated polyinosinic-polycytidilic acid (poly I:C) and lipoteichoic acid (LTA) activation of RAW 264.7 macrophages. Effects of multiple inhibitors on tumor necrosis factor (TNF)-alpha release were monitored to determine requirements for inflammatory cytokine production. Cycloheximide, monodansylcadaverine, and cytochalasin B all blocked TNF-alpha release from macrophages stimulated with LTA or poly I:C, whereas monensin only nominally reduced TNF-alpha production. Selected inhibitors of downstream signaling events reduced SR-A-dependent TNF-alpha release by >95% after stimulation with either ligand, whereas others were ineffective. The PKC inhibitor H7 reduced LTA-dependent secretion of TNF-alpha by 94% but inhibited poly I:C-dependent TNF-alpha production only by 50%. Priming of RAW 264.7 cells with interferon-gamma potentiated the response to poly I:C but did not alter inhibitor effects. These results demonstrated that for both ligands tested here, early events of receptor internalization are requisite for cellular activation. The response pattern suggests that tyrosine phosphorylation and activation of the MAP kinase pathway are key components of SR-A-mediated signal transduction cascades.

Animals↗

[Platelet antiaggregants and coronary pathology].

Platelet inhibitors have widely been studied in various clinical situations resulting from atherosclerosis of the coronary arteries. At present, aspirin is virtually the only drug that has proved to be effective in all cases where the risk of coronary thrombosis was very high. Administered in daily doses of 160 to 1,500 mg, acetylsalicylic acid reduces the frequency of coronary thrombosis and its consequence, myocardial infarction, in the following clinical situations: year following myocardial infarction, acute phase of myocardial infarction, unstable angina, year following aorto-coronary bypass, days following dilatation of the coronary arteries. Acetylsalicylic acid has been compared with heparin and anti-vitamin K agents in four trial: whatever the model studied, no difference was found in the effectiveness of the two treatments tested. Aspirin ha recently been reported as preventing myocardial infarction in healthy subjects. The practical value of this finding is questionable. The various effects of aspirin have been ascribed to the fact that it interrupts a cascade of events ranging from rupture of atherosclerosis plaques to arterial thrombosis.

Angina, Unstable↗

The substitution pattern of anthocyanidins affects different cellular signaling cascades regulating cell proliferation.

The aglycons of the most abundant anthocyanins in food, cyanidin (cy) and delphinidin (del), represent potent inhibitors of the epidermal growth factor receptor (EGFR). Structure-activity studies show that the presence of vicinal hydroxy substituents at the phenyl ring at the 2-position (B-ring) is crucial for target interaction. The presence of a single hydroxy group or introduction of methoxy substituents at the B-ring results in a substantial loss of inhibitory properties. However, biological activity is not exclusively limited to compounds bearing vicinal hydroxy groups. A contradictory structure-activity relationship is observed for the inhibition of cAMP-specific phosphodiesterases (PDEs). Of the anthocyanidins tested, malvidin, bearing methoxy substituents in the 3'- and 5'-positions, most effectively inhibited cAMP hydrolysis. The absence of methoxy groups and/or replacement by hydroxy substituents was found to strongly diminish PDE-inhibitory properties. We found that either effective EGFR inhibition or effective PDE inhibition is required to achieve a shut-down of the central mitogen-activated protein kinase (MAPK) pathway, a signaling cascade crucial for the regulation of cell growth. This is consistent with the finding that efficient reduction of cell growth is limited to anthocyanidins that are potent EGFR- or PDE-inhibitors including cy and del or malvidin (mv), respectively. In summary, depending on the substitution pattern at the B-ring, anthocyanidins interfere with different signaling cascades involved in the regulation of cell growth.

3',5'-Cyclic-AMP Phosphodiesterases↗

Angiotensin II elevates nitric oxide synthase 3 expression and nitric oxide production via a mitogen-activated protein kinase cascade in ovine fetoplacental artery endothelial cells.

Normal pregnancy is associated with high angiotensin II (ANG II) concentrations in the maternal and fetal circulation. These high levels of ANG II may promote production vasodilators such as nitric oxide (NO). ANG II receptors are expressed in ovine fetoplacental artery endothelial (OFPAE) cells and mediate ANG II-stimulated OFPAE cell proliferation. Herein, we tested whether ANG II stimulated NO synthase 3 (NOS3, also known as eNOS) expression and total NO (NO(x)) production via activation of mitogen-activated protein kinase 3/1 (MAPK3/1, also known as ERK1/2) in OFPAE cells. ANG II elevated (P < 0.05) eNOS protein, but not mRNA levels with a maximum effect at 10 nM. ANG II also dose dependently increased (P < 0.05) NO(x) production with a maximal effect at doses of 1-100 nM. Activation of ERK1/2 by ANG II was determined by immunocytochemistry and Western blot analysis. ANG II rapidly induced positive staining for phosphorylated ERK1/2, appearing in cytosol after 1-5 min of ANG II treatment, accumulating in nuclei after 10 min, and disappearing at 15 min. ANG II increased (P < 0.05) phosphorylated ERK1/2 protein levels. Activation of ERK1/2 was confirmed by an immunocomplex kinase assay using ELK1 as a substrate. PD98059 significantly inhibited ANG II-induced ERK1/2 activation, and the ANG II-elevated eNOS protein levels but only partially reduced ANG II-increased NO(x) production. Thus, in OFPAE cells, the ANG II increased NO(x) production is associated with elevated eNOS protein expression, which is mediated at least in part via activation of the mitogen-activated protein kinase kinase1 and kinase2 (MAP2K1 and MAP2K2, known also as MEK1/2)/ERK1/2 cascade. Together with our previous observation that ANG II stimulates OFPAE cell proliferation, these data suggest that ANG II is a key regulator for both vasodilation and angiogenesis in the ovine fetoplacenta.

Angiotensin II↗

Individualized heparin and protamine management in infants and children undergoing cardiac operations.

BACKGROUND: Measurements of activated coagulation time do not correlate with plasma concentration of heparin. This study investigated the effects of a patient-specific method to manage anticoagulation and its reversal in pediatric patients undergoing cardiopulmonary bypass. METHODS: Infants and children were randomly assigned to receive either a standard dose of heparin (300 IU/kg; group C, n = 13) or an individualized dose, calculated by an in vitro heparin dose-response test (group HC, n = 13). Protamine dose was based on a 1 mg/l mg ratio of total administered heparin for patients in group C and of the residual heparin concentration in group HC. RESULTS: Administered heparin was significantly higher and total protamine dose was significantly reduced in the HC group (both p < or = 0.001). There was less thrombin generation (p = 0.02) and fibrinolysis (p = 0.05) in group HC. Blood loss and requirement for transfusion of blood and fresh frozen plasma were also lower in group HC (all p < or =0.05). CONCLUSIONS: An individualized management of anticoagulation and its reversal results in less activation of the coagulation cascade, less fibrinolysis, and reduced blood loss and need for transfusions. Further studies are warranted to better define the clinical impact of these findings.

Anticoagulants↗