Craniosynostosis and Guanine Nucleotide-binding Protein Alpha Stimulating Mutation: Risk of Bleeding Diathesis and Circulatory Collapse in Patients Undergoing Cranial Vault Reconstruction.

Reconstruction of the craniosynostosis deformity is a relatively safe operation with low overall complication risks. Despite expected risk of significant blood loss, life-threatening bleeding is relatively rare, and there is a low incidence of reported deaths in the literature. Several modalities have been described for perioperative mitigation of blood loss and transfusion requirements. Due to the low overall risk of life-threatening bleeding and circulatory collapse, it is judicious that any potential causes of such unusual but potentially significant fatal bleeding complication be evaluated and reported to increase awareness for craniofacial surgeons treating these conditions. In this report and literature review, the authors present a highly unusual patient with significant bone bleeding and circulatory collapse in a metopic craniosynostosis patient with guanine nucleotide-binding protein alpha stimulating (GNAS) mutation; perform a literature review regarding bleeding diathesis in craniosynostosis patients with GNAS mutations; and suggest guidelines to potentially prevent mortality in such patients.

Diagnostic laboratory for bleeding disorders ensures efficient management of haemorrhagic disorders.

Haemorrhagic disorders like Postpartum haemorrhage and Dengue haemorrhagic fever are life threatening and requires an active and efficient transfusion service that could provide the most appropriate blood product which could be effective in managing them. This would essentially require prompt identification of the coagulopathy so that the best available product can be given to the bleeding patient to correct the identified haemostatic defect which will help control the bleeding. This would only be possible if the transfusion service has a laboratory to correctly detect the haemostatic defect and that too with an accuracy and precision which is ensured by a good laboratory quality assurance practices. These same processes are necessary for the transfusion services to ensure the quality of the blood products manufactured by them and that it contains adequate amounts of haemostasis factors which will be good to be effective in the management of haemorrhagic disorders. These issues are discussed in detail individually in the management of postpartum haemorrhage and Dengue haemorrhagic fever including when these can help in the use of rFVIIa in Dengue haemorrhagic fever. The requirements to ensure good-quality blood products are made available for the management of these disorders and the same have also been described.

Effective reversal of edoxaban-associated bleeding with four-factor prothrombin complex concentrate in a rabbit model of acute hemorrhage.

BACKGROUND: Edoxaban is an oral, selective direct factor Xa inhibitor approved in Japan for venous thromboembolism prevention after orthopedic surgery. Data are lacking regarding reversal strategies for edoxaban; this study assessed whether four-factor prothrombin complex concentrate (Beriplex/Kcentra; CSL Behring GmbH, Marburg, Germany) can effectively reverse its effects on hemostasis using a previously described rabbit model. METHODS: The study comprised assessments of thrombin generation in vitro, pharmacokinetic parameters, and edoxaban reversal in vivo. In a blinded in vivo stage, a standardized kidney incision was performed in animals (n = 11 per group) randomized to receive vehicle + saline, edoxaban (1,200 µg/kg) + saline, or edoxaban (1,200 µg/kg) + four-factor prothrombin complex concentrate (50 IU/kg). Animals were monitored for treatment impact on hemostasis and coagulation parameters. Data are median (range). Statistical tests were adjusted for multiple testing. RESULTS: Edoxaban administration increased blood loss (30 [2 to 44] ml) and time to hemostasis (23 [8.5 to 30.0] min) compared with the control group (3 [1 to 8] ml and 3 [2.0 to 5.0] min, respectively). Biomarkers of coagulation (prothrombin time, activated partial thromboplastin time, whole blood clotting time) and thrombin generation parameters (e.g., peak thrombin, endogenous thrombin potential, lag time) were also affected by edoxaban. Administration of four-factor prothrombin complex concentrate significantly reduced time to hemostasis (to 8 [6.5 to 14.0] min, observed P < 0.0001) and total blood loss (to 9 [4 to 22] ml, observed P = 0.0050) compared with the edoxaban + saline group. Of the biomarkers tested, prothrombin time, whole blood clotting time, and endogenous thrombin potential correlated best with clinical parameters. CONCLUSION: In a rabbit model of hemostasis, four-factor prothrombin complex concentrate administration significantly decreased edoxaban-associated hemorrhage.

Tranexamic acid without prophylactic factor replacement for prevention of bleeding in hereditary bleeding disorder patients undergoing endoscopy: a pilot study.

The risk of bleeding in patients with hereditary bleeding disorders (HBD) undergoing gastro-intestinal (GI) endoscopic procedures is unknown but guidelines generally recommend correction of factor deficiency. Investigate the safety of oral tranexamic acid (TA) without prophylactic factor replacement to prevent bleeding complications in patients with HBD undergoing elective GI endoscopic procedures. A prospective single-arm pilot study testing the feasibility of using TA, without prophylactic factor replacement or desmopressin preprocedure, for prevention of bleeding complications following elective standard risk (<1% risk of bleeding) endoscopic procedures in patients with HBD. Baseline factor levels, haemoglobin and iron studies (IS) were measured preprocedure. Primary outcome of bleeding (NCI CTCAE v3.0 Bleeding Scale) was undertaken by patient review and repeat Hb, IS on day 21. Twenty-eight patients underwent 32 GI endoscopic procedures from September 2010 until June 2012. The median age was 53 years (range 24-75 years) and disease types included mild haemophilia A/B (n = 12), severe haemophilia A/B (n = 9), von Willebrand disease (n = 5), FXI deficiency (n = 1) and FVII deficiency (n = 1). Procedures performed included 11 gastroscopies, 12 colonoscopies, 8 gastroscopies and colonoscopies and 1 flexible sigmoidoscopy. Fourteen standard risk procedures and two high risk procedures were performed. Two patients experienced Grade 1 bleeding and one patient experienced Grade 2 bleeding. This study suggests that TA without prophylactic factor replacement may be a safe approach for mild and moderate HBD patients undergoing standard risk endoscopic procedures, particularly where no biopsy is performed. These findings should be confirmed in a larger study.

WFH: closing the global gap--achieving optimal care.

For 50 years, the World Federation of Hemophilia (WFH) has been working globally to close the gap in care and to achieve Treatment for All patients, men and women, with haemophilia and other inherited bleeding disorders, regardless of where they might live. The WFH estimates that more than one in 1000 men and women has a bleeding disorder equating to 6,900,000 worldwide. To close the gap in care between developed and developing nations a continued focus on the successful strategies deployed heretofore will be required. However, in response to the rapid advances in treatment and emerging therapeutic advances on the horizon it will also require fresh approaches and renewed strategic thinking. It is difficult to predict what each therapeutic advance on the horizon will mean for the future, but there is no doubt that we are in a golden age of research and development, which has the prospect of revolutionizing treatment once again. An improved understanding of "optimal" treatment is fundamental to the continued evolution of global care. The challenges of answering government and payer demands for evidence-based medicine, and cost justification for the introduction and enhancement of treatment, are ever-present and growing. To sustain and improve care it is critical to build the body of outcome data for individual patients, within haemophilia treatment centers (HTCs), nationally, regionally and globally. Emerging therapeutic advances (longer half-life therapies and gene transfer) should not be justified or brought to market based only on the notion that they will be economically more affordable, although that may be the case, but rather more importantly that they will be therapeutically more advantageous. Improvements in treatment adherence, reductions in bleeding frequency (including microhemorrhages), better management of trough levels, and improved health outcomes (including quality of life) should be the foremost considerations. As part of a new WFH strategic plan (2012-2014) the WFH has identified several key initiatives for particular emphasis - continuation of the Global Alliance for Progress (GAP) program, a new initiative to address underserved countries and regions (The Cornerstone Initiative), enhancing health outcomes research and analysis, and a new research mentorship program. Despite our progress to date in closing the global gap in care, our work is not complete. Too many patients remain undiagnosed and too few receive adequate treatment. This paper will also discuss historical, present and future challenges and opportunities to close the gap in care and achieve Treatment for All.

Low plasma levels of tissue factor pathway inhibitor in patients with congenital factor V deficiency.

Severe factor V (FV) deficiency is associated with mild to severe bleeding diathesis, but many patients with FV levels lower than 1% bleed less than anticipated. We used calibrated automated thrombography to screen patients with severe FV deficiency for protective procoagulant defects. Thrombin generation in FV-deficient plasma was only measurable at high tissue factor concentrations. Upon reconstitution of FV-deficient plasma with purified FV, thrombin generation increased steeply with FV concentration, reaching a plateau at approximately 10% FV. FV-deficient plasma reconstituted with 100% FV generated severalfold more thrombin than normal plasma, especially at low tissue factor concentrations (1.36 pM) or in the presence of activated protein C, suggesting reduced tissue factor pathway inhibitor (TFPI) levels in FV-deficient plasma. Plasma TFPI antigen and activity levels were indeed lower (P < .001) in FV-deficient patients (n = 11; 4.0 +/- 1.0 ng/mL free TFPI) than in controls (n = 20; 11.5 +/- 4.8 ng/mL), while persons with partial FV deficiency had inter-mediate levels (n = 16; 7.9 +/- 2.5 ng/mL). FV immunodepletion experiments in normal plasma and surface plasmon resonance analysis provided evidence for the existence of a FV/TFPI complex, possibly affecting TFPI stability/clearance in vivo. Low TFPI levels decreased the FV requirement for minimal thrombin generation in FV-deficient plasma to less than 1% and might therefore protect FV-deficient patients from severe bleeding.

Anesthetic implications for the patient with osteogenesis imperfecta.

Osteogenesis imperfecta is an inherited disorder of the connective tissue stemming from gross abnormalities in collagen formation and structure. Affected patients fall into 4 classifications each displaying the similar properties of easily fractured bones, hypermobile joints, blue or gray sclera, skeletal deformities, and fragile skin. More severe forms of the disease may manifest platelet dysfunction, cardiac anomalies, hypermetabolic syndromes, respiratory compromise, and/or basilar invagination. Treatment of osteogenesis imperfecta is mainly supportive, consisting of prompt surgical treatment of fractures to prevent deformity and maintaining mobility to lessen the chance of pulmonary or cardiovascular complications. These treatment modalities make anesthesia of paramount importance. Current literature exposes many potential anesthetic complications associated with osteogenesis imperfecta. The research shows that implications range from simply positioning the patient on the operating room table to management of rare occurrences such as malignant hyperthermia and basilar invagination. Commonly encountered complications include a difficult airway, intraoperative bleeding due to platelet dysfunction, respiratory compromise due to skeletal deformity, and congenital cardiac anomalies. Proper preparation and preoperative assessment is important, as is the choice of anesthetic technique. Correct identification of risk factors and optimization of health before surgery should lead to an uneventful anesthetic course.

Characterization of a large cohort of patients with unclassified bleeding disorder; clinical features, management of haemostatic challenges and use of global haemostatic assessment with proposed recommendations for diagnosis and treatment.

INTRODUCTION: There is an unmet need to characterize the diagnosis and management of patients with an unclassified bleeding disorder (UBD). METHODS: Retrospective review of registered patients with UBD at our centre. Assessment including rotational thromboelastometry (ROTEM) and thrombin generation (TG) were used. RESULTS: A total of 124 patients were identified; 91% female. Mean age of presentation was 38.3 years. Mean bleeding score was 8.8 (standard deviation [SD] 3.8); 6.6 in men (SD 1.4) and 9.7 in women (SD 3.3), which was significantly different (P < .05). In women, after deduction of scores for menorrhagia and postpartum haemorrhage, the mean score was 6.4 which was not significantly different to the male score (P = .11). Twenty-three percent of patients have been transfused, 61% women had treatment for menorrhagia and 17% for epistaxis. TxA and desmopressin were effective at preventing bleeding in 69 procedures and 13 deliveries. TG revealed 26% patients with a long lag time and 19% with a decreased endogenous thrombin potential but no diagnostic pattern was seen. ROTEM (NATEM) was unable to characterize patients; 9% had a prolonged clot time or maximum lysis. ThromboGenomics was normal in 45 tested patients. CONCLUSIONS: We provide data which shows the bleeding score is biased towards gynaecological bleeding but which remains elevated even when the bleeding score is deducted. Tranexamic acid and desmopressin are effective as haemostatic prophylaxis but there is an urgent need for clinical trials. In conclusion, we describe the use of the bleeding score in these patients and phenotype, diagnosis (including ThromboGenomic testing) and management with practice recommendations.

Effects of plasma dilution on tissue-factor-induced thrombin generation and thromboelastography: partly compensating role of platelets.

BACKGROUND: Bleeding upon major surgery or severe trauma is treated by transfusion with crystalloids, colloids, or plasma. This treatment, however, can lead to dilutional coagulopathy and impaired hemostasis. We investigated the suitability of two integrative coagulation tests to measure the hemostatic activity of diluted plasma. STUDY DESIGN AND METHODS: Plasma from healthy donors was diluted in vitro with saline or colloid (venofundin or gelofusin). Coagulant activity in response to tissue factor was monitored by calibrated automated thrombin (CAT) generation and rotational thromboelastography (TEG), detecting formation of elastic fibrin clots. Plasma from patients receiving fluid infusion during coronary artery bypass grafting (CABG) was analyzed with the same assays. RESULTS: Optimal activity of CAT and TEG assays required the presence of 10 pmol per L tissue factor and 4 micromol per L phospholipid vesicles or 100 x 10(9) platelets (PLTs) per L. Strikingly, thrombin generation and clot formation became impaired at a higher extent of dilution with PLTs present (< or =40% plasma) than with phospholipid vesicles present (< or =60% plasma). Colloids aggravated the dilution effect on clot formation, but FFP antagonized the dilution effect on thrombin and clot formation. In contrast, fibrinogen and Factor (F)XIII only restored the impaired clot formation. In plasma samples from patients undergoing CABG, CAT and TEG assay variables were altered to an extent corresponding with the volume of fluid infusion. CONCLUSION: Thrombin generation and clot formation are reduced at a plasma dilution of more than 40 percent. In either process, PLTs can partly compensate for the dilution effect. In vitro dilution with colloids impaired fibrin clot elasticity compared to saline.

Continuous bladder irrigation prevents hemorrhagic cystitis after allogeneic hematopoietic cell transplantation.

Hemorrhagic cystitis is 1 of the most troublesome complications of hematopoietic cell transplantation conditioning regimens. We conducted a nonrandomized controlled clinical study to investigate the role of continuous bladder irrigation in addition to mesna, hydration, and alkalization in the prevention of hemorrhagic cystitis after allogeneic hematopoietic cell transplantation. A total of 80 eligible patients entered the study. From May 2006, 40 patients who underwent allogeneic hematopoietic cell transplantation received continuous bladder irrigation in addition to the common protocol. A historical control group of 40 consecutive patients with same inclusion criteria who did not receive bladder irrigation was enrolled from before May 2006. Hemorrhagic cystitis occurred in 50% of patients in the no bladder irrigation group versus 32% in bladder irrigation group (P = 0.11). The mean duration of hemorrhagic cystitis was significantly reduced in the bladder irrigation group (10 vs. 18 days; P = 0.02). Duration of hospitalization was significantly shorter in the bladder irrigation group (30.2 vs. 39.6; P < 0.001). Late-onset hemorrhagic cystitis that occurred beyond 4 weeks after allo-hemorrhagic cystitis happened more significantly in the no bladder irrigation group (P = 0.001). High-grade hemorrhagic cystitis was more frequently associated with high-grade graft-versus-host disease within 30 days after transplant (P = 0.06). In general, continuous bladder irrigation added to mesna, hydration, and alkalization regimens was well tolerated, decreased the complications of hemorrhagic cystitis, and may be useful in hematopoietic cell transplantation patients. However, more investigations with randomized controlled clinical trials with more patients are needed.

Hemorrhagic cardiomyopathy in male mice treated with an NNRTI: the role of vitamin K.

Dietary dosing of the non-nucleoside reverse transcriptase inhibitor (NNRTI) TMC125, under development for treatment of HIV-1, resulted in a syndrome in male mice in a previous experiment that was termed hemorrhagic cardiomyopathy. In literature, this syndrome, which was described in rodent species only, was linked to vitamin K deficiency. Two mechanistic studies were conducted, one with dietary administration and a second with gavage. The syndrome was reproduced in only 1 male mouse after continuous dietary dosing, and TMC125 was demonstrated to affect coagulation parameters (prothrombin time [PT], activated partial thromboplastin time [APTT], clotting factors II, VII and XI), particularly in males. This was counteracted by vitamin K supplementation, supporting the hypothesis that the effects were mediated via a vitamin K deficiency. It is therefore concluded that the observed cardiac changes were not caused by a direct cardiotoxic effect but occurred after a state of disabled clotting ability with subsequent effects on mouse cardiac muscle. Therefore, clotting times can be used as adequate safety biomarkers in clinical trials. To date, no changes have been observed at therapeutic doses of TMC125, following human monitoring of PT and APTT. One other NNRTI, Efavirenz (Sustiva), has been reported to cause prolongation of coagulation times in rats and monkeys.

S-allyl cysteine ameliorates cyclophosphamide-induced downregulation of urothelial uroplakin IIIa with a concomitant effect on expression and release of CCL11and TNF-α in mice.

BACKGROUND: The aim of this study was to evaluate the modulatory effect of S-allyl cysteine against cyclophosphamide-induced changes in uroplakin IIIa, CCL11 and TNF-α. METHODS: Mice were treated with cyclophosphamide (200mg/kg×7 d, ip). S-allyl cysteine (150mg/kg×7d, ip), and comparator compound mesna (40mg/kg×7d, ip) were administered 1h before and 4h after each cyclophosphamide dose. The urinary bladder was analysed for mRNA and protein changes in uroplakin IIIa (UPIIIa), CCL11 and TNF-α and histopathological findings. RESULTS: Cyclophosphamide caused hemorrhagic cystitis formation and downregulation of UPIIIa. These changes were accompanied by upregulation of CCL11 and TNF-α. S-allyl cysteine attenuated these changes including protection at histological level. Mesna which was used as a comparator drug also showed protection. However, relatively S-allyl cysteine showed a stronger protective effect than mesna. CONCLUSION: These findings highlight a correlation between downregulaion of UPIIIa and enhanced production of inflammatory biomarkers and protective effects of S-allyl cysteine which has been reported to be a potent uroprotective agent. The present study strengthens its role which could be clinically exploited in chemotherapy regimen.

Erythrocyte-Derived Nanoparticles as a Theranostic Agent for Near-Infrared Fluorescence Imaging and Thrombolysis of Blood Clots.

Ischemic stroke occurs when a blood clot obstructs or narrows the arteries that supply blood to the brain. Currently, tissue plasminogen activator (tPA), a thrombolytic agent, is the only United States Food and Drug Administration (FDA)-approved pharmacologic treatment for ischemic stroke. Despite its effective usage, the major limitation of tPA that stems from its short half-life in plasma (≈5 min) is the potential for increased risk of hemorrhagic complications. To circumvent these limitations, herein, the first proof-of-principle demonstration of a theranostic nanoconstruct system derived from erythrocytes doped with the FDA-approved near-infrared (NIR) imaging agent, indocyanine green, and surface-functionalized with tPA is reported. Using a clot model, the dual functionality of these nanoconstructs in NIR fluorescence imaging and clot lysis is demonstrated. These biomimetic theranostic nanoconstructs may ultimately be effective in imaging and treatment of blood clots involved in ischemic stroke.

Quantitation of fragment X formation during thrombolytic therapy with streptokinase and tissue plasminogen activator.

We have determined the extent of fragment X formation during thrombolytic therapy by integration over time of the plasma fibrinopeptide B beta 1-42 concentration. This peptide is quantitatively released when fragment X is formed by plasmin action on fibrinogen or fibrin I. In response to streptokinase (SK) and rt-PA, 264 +/- 54 and 95 +/- 12 mg/dl respectively of fibrinogen was converted to fragment X. By immunoblotting, fragment X was demonstrated as early as 5 min after SK and 30 min after rt-PA, and was still evident 24 h after treatment. Patients treated with SK showed extensive further plasmin degradation of fragment X to fragments Y and D. Thus fragment X concentrations tend to be more similar in the two groups than would be expected from the extent of fibrinogen breakdown. Fragment X forms clots, but these have lower tensile strength and are more susceptible to further plasmin lysis than clots of fibrin. Thus the similar bleeding observed in the two treatment groups might be a reflection of their similar plasma fragment X concentrations.

Women with bleeding disorders.

Menorrhagia, or excessive menstrual bleeding, is a common clinical problem affecting reproductive-age women; however, the cause is undetermined in 50% of cases. Von Willebrand disease (VWD) or other bleeding disorders may be the underlying source of heavy bleeding. Women with menorrhagia and/or VWD are at increased risk for several conditions including anemia, bleeding during pregnancy, post-partum hemorrhage, and reduced quality of life (OOL). Proper diagnosis and management can decrease complications and unnecessary surgical interventions. The Division of Blood Disorders (DBD) at the Centers for Disease Control and Prevention (CDC) has implemented studies to ascertain physician awareness of bleeding disorders, establish prevalence in the U.S., and determine the best treatment options.

Venomous snakebites in children in southern Croatia.

This retrospective study represents observation of 160 children and adolescents aged up to 18 years that experienced venomous snakebites in southern Croatia and were treated in the Clinical Department of Infectious Diseases in the University Hospital Centre Split from 1979 to 2013. The main purpose of this research was to determine the epidemiological characteristics, clinical presentation, local and general complications, and received treatment. Most bites occurred during warm months, from early May to late August (80%), mostly in May and June. Upper limb bites were more frequent (59%) than lower limb bites (40%). Out of the total number of poisoned children, 24% developed local, and 25% general complications. The most common local complications were haemorrhagic blisters that occurred in 20% children, followed by compartment syndrome presented in 7.5% patients. The most dominated general complication was cranial nerve paresis or paralysis, which was identified in 11.2% patients, whereas shock symptoms were registrated in 7% children. According to severity of poisoning, 9.4% children had minor, 35% mild, 30.6% moderate, and 24.4% had severe clinical manifestation of envenomation. Only one (0.6%) child passed away because of snakebite directly on the neck. All patients received antivenom produced by the Institute of Immunology in Zagreb, tetanus prophylaxis as well, and almost all of them received antibiotics, and a great majority of them also received corticosteroids and antihistamines. Neighter anaphylactic reaction nor serum disease were noticed in our patients after administrating antivenom. A total of 26% children underwent surgical interventions, and incision of haemorrhagic blister was the most common applied surgical treatment, which was preformed in 15.6% patients, while fasciotomy was done in 7.5% subjects. All of our surgically treated patients recovered successfully.

International warfarin genotype-guided dosing algorithms in the Turkish population and their preventive effects on major and life-threatening hemorrhagic events.

AIM: To determine the accuracy of international warfarin pharmacogenetic algorithms developed on large multiethnic cohorts (comprising more than 1000 subjects) to predict therapeutic warfarin doses in Turkish patients. MATERIALS & METHODS: We investigated two Turkish warfarin-treated cohorts: patients with no history of hemorrhagic or thromboembolic event and patients with major and life-threatening hemorrhagic events. RESULTS: International pharmacogenetic algorithms showed good performances in predicting the therapeutic dose of patients with no history of bleedings, but they did not significantly detect the incorrect warfarin dose of patients with major and life-threatening hemorrhagic events. CONCLUSION: Although genetic information can predict the therapeutic warfarin dose, the accuracy of the international pharmacogenetic algorithms is not sufficient to be used for warfarin screening in Turkish patients.

Experimental model of hyperfibrinolysis designed for rotational thromboelastometry in children with congenital heart disease.

We assessed an in-vitro model of hyperfibrinolysis using rotational thromboelastometry (ROTEM) by the addition of increasing concentrations of tissue-type plasminogen activator (t-PA) on whole blood obtained from children undergoing cardiac surgery. We assessed the relevance of this model by repeating the tests in the same population after tranexamic acid (TXA) infusion. In addition, we determined the sensitivity and specificity of ROTEM parameters to detect the different degrees of fibrinolysis. Blood samples obtained from 20 children were analyzed at two predefined timepoints: after induction of anesthesia, before TXA (baseline), and at the end of surgery during TXA infusion (end surgery). At baseline, an extrinsic activation with tissue factor (EXTEM) test was performed without and with increasing concentration of t-PA (102, 255, 512, 1024, 1535, and 2539 units t-PA/ml). At the end of surgery, a second EXTEM test was performed without and with two different t-PA concentrations (1535 and 2539 units t-PA/ml). At baseline, increasing t-PA concentrations in the EXTEM test induced a gradual increase of hyperfibrinolysis characterized by a reduction in clot firmness and stability parameters. In the presence of TXA, t-PA-induced hyperfibrinolysis was completely abolished. Lysis-onset time (LOT) and degree of fibrinolysis measured at 30 min (LI30) best assessed the degree of fibrinolysis. This in-vitro model of t-PA-induced hyperfibrinolysis using the EXTEM test of ROTEM may represent a promising tool to assess hyperfibrinolysis in the pediatric population. In addition, we observed that LOT and LI30 should be considered as the best parameters to detect different degrees of fibrinolysis.

In utero transplantation of wild-type fetal liver cells rescues factor X-deficient mice from fatal neonatal bleeding diatheses.

Factor X (FX)-deficient embryos suffer partial embryonic lethality with approximately 30% of the embryos arresting at midgestation. The remaining animals survive to term but die perinatally mainly from abdominal or intracranial hemorrhage. We have rescued FX-deficient mice by transplanting fetal liver cells from FX+/+, Rosa26 fetuses into midgestation embryos derived from FX+/- heterozygous crosses. FX-/- embryos were born at the expected frequency and approximately 50% of the FX-/- neonates survived longer than 4 months. FX-/- embryos receiving saline injections that survived to term died perinatally similar to untreated FX-deficient mice. The plasma levels of FX in the rescued 16-week-old FX-/- mice were approximately 1-6% of wild-type levels. beta-Galactosidase-staining cells derived from the donor Rosa26 fetal liver cells were detected in 47% of the livers of adult mice. In addition, donor-derived cells were also recovered in the bone marrow, spleen, lung, and occasionally in the brain and testis. These results suggest that in utero cell transplantation could be an effective therapeutic strategy to treat pathologies resulting from the deficiency of hepatic-expressed factors.