The epidemiology of osteonecrosis: findings from the GPRD and THIN databases in the UK.

UNLABELLED: We conducted a case-control study to examine osteonecrosis (ON) incidence, patient characteristics, and selected potential risk factors using two health record databases in the UK. Statistically significant risk factors for ON included systemic corticosteroid use, hospitalization, referral or specialist visit, bone fracture, any cancer, osteoporosis, connective tissue disease, and osteoarthritis. INTRODUCTION: The purpose of this case-control study was to examine the incidence of osteonecrosis (ON), patient characteristics, and selected potential risk factors for ON using two health record databases in the UK: the General Practice Research Database and The Health Improvement Network. METHODS: ON cases (n = 792) were identified from 1989 to 2003 and individually matched (age, sex, and medical practice) up to six controls (n = 4,660) with no record of ON. Possible risk factors were considered for inclusion based on a review of published literature. Annual incidence rates were computed, and a multivariable logistic regression model was derived to evaluate selected risk factors. RESULTS: ON of the hip represented the majority of cases (75.9%). Statistically significant risk factors for ON were systemic corticosteroid use in the previous 2 years, hospitalization, referral or specialist visit, bone fracture, any cancer, osteoporosis, connective tissue disease, and osteoarthritis within the past 5 years. Only 4.4% of ON cases were exposed to bisphosphonates within the previous 2 years. CONCLUSIONS: This study provides further perspective on the descriptive epidemiology of ON. Studies utilizing more recent data may further elucidate the understanding of ON key predictors.

Fragility fractures of the hip and femur: incidence and patient characteristics.

SUMMARY: Using national discharge and medical claims data, we studied the epidemiology of femoral fractures from 1996 to 2006. The annual hip fracture incidence declined from 600/100,000 to 400/100,000, without decline in the more rare femur fractures. Incidence rates for subtrochanteric and femoral shaft fractures were each below 20 per 100,000. INTRODUCTION: This study's purpose is to describe the site-specific epidemiology of femur fractures among people aged 50 and older. METHODS: Using the National Hospital Discharge Survey from 1996 to 2006 and a large medical claims database (MarketScan), we studied epidemiology of all femur fractures. Hip fractures were grouped together; subtrochanteric, shaft, and distal femur fractures were kept separate. RESULTS: In females, the overall hospital discharge rates of hip fracture decreased from about 600/100,00 to 400/100,000 person-years from 1996 to 2006. Subtrochanteric, femoral shaft, and lower femur rates remained stable, each approximately 20 per 100,000 person-years. Similar trends but lower rates existed in males. No significant trends were found in any of these fractures during the more recent years of 2002-2006 (MarketScan data). Using MarketScan, the overall incidence of hip fracture was <300/100,000 person-years; incidence of subtrochanteric and femoral shaft fractures combined was <25/100,000 person-years and distal femur fracture incidence was <18/100,000 person-years in females; rates were lower in males. The incidence of hip and other femur fractures increased exponentially with age. CONCLUSIONS: We found no evidence of an increasing incidence of any femoral fracture. Hip fracture incidence is declining but the incidence of each of the more rare femur fractures (distal to the lesser trochanter) is stable over time.

Breast-feeding and risk of childhood acute leukemia.

BACKGROUND: Breast-feeding is well known to have a protective effect against infection in infants. Although the long-term effects of breast-feeding on childhood cancer have not been studied extensively, a protective effect against childhood Hodgkin's disease and lymphoma has been suggested previously from small investigations. In this study, we tested the hypothesis that breast-feeding decreases the risk of childhood acute leukemia. METHODS: A total of 1744 children with acute lymphoblastic leukemia (ALL) and 1879 matched control subjects, aged 1-14 years, and 456 children with acute myeloid leukemia (AML) and 539 matched control subjects, aged 1-17 years, were included in the analysis. Information regarding breast-feeding was obtained through telephone interviews with mothers. All leukemias combined, histologic type of leukemia (ALL versus AML), immunophenotype of ALL (early pre-B cell, pre-B cell, or T cell), and morphology of AML were assessed separately in the data analysis. RESULTS: Ever having breast-fed was found to be associated with a 21% reduction in risk of childhood acute leukemias (odds ratio [OR] for all types combined = 0.79; 95% confidence interval [CI] = 0.70-0.91). A reduction in risk was seen separately for AML (OR = 0.77; 95% CI = 0.57-1.03) and ALL (OR = 0.80; 95% CI = 0.69-0.93). The inverse associations were stronger with longer duration of breast-feeding for total ALL and AML; for M0, M1, and M2 morphologic subtypes of AML; and for early pre-B-cell ALL. CONCLUSION: In this study, breast-feeding was associated with a reduced risk of childhood acute leukemia. If confirmed in additional epidemiologic studies, our findings suggest that future epidemiologic and experimental efforts should be directed at investigating the anti-infective and/or immune-stimulatory or immune-modulating effects of breast-feeding on leukemogenesis in children.

Ceruloplasmin-anion interaction. A circular dichroism spectroscopic study.

The effect of anion binding to ceruloplasmin has been studied using absorption and cirbular dichroism spectral data. At anion to ceruloplasmin molar ratios approaching infinite, OCN-, N3- and SCN- bind to ceruloplasmin giving rise to similar alterations in circular dichroism and absorption spectra. The positive bands at 610 and 520 nm in circular dichroism spectra disappear, a negative one apperars at 600 nm and the peak at 450 nm is only slightly modified. There is a new negative band at 410 nm well-defined in OCN- ceruloplasmin spectra. The decrease in absorption at 610 nm is ascribed to the disruption of one type I Cu-S(cysteine) bond owing presumably to the changes induced by anions in the protein secondary structure. The new band at 410 nm is assigned to a charge transfer transition from the ligand replacing cysteine at its binding site. Both absorption and circular dichroism spectra show isobestic points indicating that anion binding to the enzyme, disruption of one of the two type I Cu-S bonds and coordination of this Cu to another protein residue take place simultaneously.

RAS oncogene mutations and outcome of therapy for childhood acute lymphoblastic leukemia.

Activating mutations in the RAS oncogenes are among the most common genetic alterations in human cancers, including patients with acute lymphoblastic leukemia (ALL). We sought to define the frequency and spectrum, and possible prognostic importance, of N- and K-RAS mutations in children with ALL treated with contemporary therapy. Leukemic blast DNA from 870 children was analyzed for the presence of activating mutations in the N- or K-RAS oncogenes using a sensitive mutation detection algorithm. RAS mutations were present in the blasts of 131 (15.1%) pediatric ALL patients. The spectrum of mutations included 81 (9.3%) mutations of codons 12/13 of N-RAS, 12 (1.4%) mutations of codon 61 of N-RAS, 39 (4.5%) mutations of codons 12/13 of K-RAS, and 2 (0.2%) mutations of codon 61 of K-RAS. The presence of N- or K-RAS mutations was not associated with white blood cell count at diagnosis, sex, race, extramedullary testicular involvement, central nervous system disease, or NCI/CTEP ALL Risk Group. Patients with an exon 1 K-RAS mutation (codons 12/13) were significantly younger at diagnosis (P=0.001) and less frequently B-lineage phenotype (P=0.01). RAS mutation status did not predict overall survival, event-free survival and disease-free survival. While N- and K-RAS mutations can be identified in 15% of children with newly diagnosed ALL, they do not represent a significant risk factor for outcome using contemporary chemotherapy regimens.

Interaction of alpha 2-macroglobulin-bound thrombin with hirudin.

The human thrombin bound to alpha 2-macroglobulin (alpha 2 M) in a 1:1 stoichiometry is still able to interact with one of its specific inhibitors, hirudin. The dissociation constant of the complex hirudin--alpha 2M-bound thrombin is 1 X 10(-7) M, whatever the mode of thrombin binding, covalent or non-covalent.

Structural arrangement in the alpha 2-macroglobulin--thrombin complex.

The cysteine sulfhydryl groups of alpha 2-macroglobulin (alpha 2M) generated upon thrombin complex formation are in contact with the proteinase surface as evidenced by singlet--singlet energy transfer measurements from N-(iodoacetylaminoethyl)-5-naphthylamine-1-sulfonic acid-labeled thiol functions of alpha 2M to fluorescein isothiocyanate-labeled thrombin. The thrombin-alpha 2M binding is normally covalent, but the presence of hydroxylamine during the reaction leads to the formation of a non-covalent complex. The transfer energy determinations show that the alpha 2M binding sites of thrombin are quite similar, whatever covalent or non-covalent binding occurs.

Accuracy of DNA amplification from archival hematological slides for use in genetic biomarker studies.

Archival slides are a potentially useful source of DNA for mutation analyses in large population-based studies. However, it is unknown whether specimen age or histological stains alter the accuracy of Taq polymerase or induce secondary mutations in sample DNA. To address this question, we evaluated five methods for extraction of genomic DNA from archival bone marrow slides of 17 leukemia patients and analyzed exons 1 and 2 of the N- and K-ras genes for the presence of mutations. Of the five methods, optimal DNA purification was achieved by boiling and phenol:chloroform extraction. N-and K-ras exons 1 and 2 were independently amplified using 35 cycles of PCR, and 6-12 clones for each exon were isolated and individually sequenced for each patient. Mutations were confirmed by repeat extraction, cloning, and sequencing. Sixteen of 17 patient samples were successfully amplified (94%), including slides up to 29 years old. Twelve slides had been stained with Wright-Giemsa, I stained with toluidine blue, and 4 were unstained. A total of 16 single-base mutations were identified of 33,840 nucleotides sequenced. No insertions or deletions were identified. Six of 16 single-base mutations were previously described activating mutations in codon 13 of N-ras exon 1. The 10 other mutations were in other regions of the N- and K-ras genes and were not reproduced after repeat extraction, cloning, and sequencing. The frequency of these other alterations was I of 3384 bp. This value is comparable with the inherent error frequency for Taq polymerase. Our findings suggest that high fidelity DNA amplification can be achieved using archival hematological slides as old as 29 years and can be reliably used in genetic analyses.

Autologous bone marrow transplantation in acute myeloid leukemia: the University of Minnesota experience.

PURPOSE: To report the outcome of autologous bone marrow transplantation for patients with acute myeloid leukemia (AML) in first or greater complete remission (CR) treated by autologous bone marrow transplantation using two different preparatory regimens. METHODS AND MATERIALS: Between September 1986 and August 1993, 75 patients with AML ranging in age from 6 months to 58 years underwent autologous bone marrow transplantation using previously harvested and frozen unpurged (n = 6) or 4-hydroperoxycyclophosphamide purged marrows (n = 69). Patients were in first CR (n = 44) or beyond first CR (n = 31). The preparative regimen consisted of 120 mg/kg of cyclophosphamide (CY) and 1320 cGy total body irradiation (TBI) in eight fractions over 4 days (CY/TBI) in 29 patients; and 16 mg/kg of Busulfan (BU) and 200 mg/kg of CY (BU/CY) in 46 patients. Thirty-five of these 75 patients (18 CY/TBI and 17 BU/CY) were part of a randomized trial comparing the two preparative regimens. RESULTS: At 2 years, overall survival and disease-free survival (DFS) were 49% [95% confidence interval (C.I.) 37-61%] and 43% (95% C.I. 32-55%), respectively. Patients in first CR had a significantly better outcome than patients beyond first CR with an estimated 2-year DFS of 59% (95% C.I. 44-74%) vs. 21% (95% C.I. 5-36%, log-rank p = 0.0001), respectively. For patients conditioned with CY/TBI, the estimated 2-year DFS was 52% compared to 39% for BU/CY (log-rank p = 0.35). Estimated 2-year relapse rates were 44% vs. 56% (log-rank p = 0.40), respectively. For patients in first CR, no differences in DFS were observed between the two regimens (2-year estimates 69% vs. 55% log-rank p = 0.52). Patients beyond first CR had a significantly improved DFS with the CY/TBI regimen (2-year estimates of 38% vs. 7%, log-rank p = 0.04). No differences were found between the two regimens in terms of time to WBC engraftment, absolute neutrophil count of > 500, incidence of bacteremias, or median time to hospital discharge. Interstitial pneumonitis developed in two patients (one BU/CY, one CY/TBI) and venoocclusive disease developed in seven BU/CY patients (Fishers exact test p = 0.04). CONCLUSIONS: For patients beyond first CR, the CY/TBI regiment provided a better outcome, with a significantly better disease-free survival and less venoocclusive disease. For patients in first CR, no significant difference between the two regimens was found. The high relapse rate, especially for patients with advanced disease, emphasizes the need for early transplantation and for new strategies to improve outcome.

Immunoregulatory abnormalities in patients with Epstein-Barr virus-associated B cell lymphoproliferative disorders.

EBVirus-associated B cell lymphoproliferative disorder (BLPD) is a recognized complication of primary immunodeficiency and organ as well as bone marrow transplantation. Although the nature of the immune defects that predispose to the development of BLPD are unknown, it is postulated that aberrant T cell responses are involved. It is our hypothesis that unbalanced lymphokine production is a major contributory factor to abnormal B cell growth in response to EBV, resulting in BLPD. Since IFN-alpha and IL-4 are important regulators of B cell proliferation and also regulate the synthesis of IgE, we determined serum levels of IFN-alpha, IL-4, and IgE in 8 patients with newly diagnosed BLPD. Comparison was made to healthy recipients of organ transplants on immunosuppressive therapy without BLPD, and normal EBV seropositive controls. Levels of serum IL-4 were significantly elevated in both patients with BLPD as well as in healthy immunosuppressed organ transplant recipients as compared with normal healthy individuals. Patients with BLPD exhibited a combination of significantly lower levels of serum IFN-alpha, and significantly higher levels of serum IgE than either healthy EBV seropositive individuals or healthy recipients of organ transplants on immunosuppressive therapy. These results suggest that imbalance in the proportions of circulating cytokines favoring B cell proliferation may be contributing to the development of EBV-associated BLPD. The potential significance of the finding of low IFN-alpha in patients who develop BLPD is exemplified by our recent success in the treatment of BLPD with IFN-alpha and intravenous IgG.

Studies on prothrombin complex concentrates contact factors, complement components and proteinase inhibitors.

The behaviour of contact factors, complement components and antiproteases during the preparation of prothrombin complex concentrates by adsorption of the clotting components on DEAE-Sephadex has been studied. The pro-enzymes: factors XII, XI and prekallikrein were removed by pre-elution in function of the salt concentration. In contrast, high molecular weight kininogen was considerably enriched in PCC preparations. C4 of the complement system displayed an analogous behaviour. C1s reached a 4-5 fold plasma concentration but C3 only 30% of the normal plasma level. The prothrombin complex concentrate contained no antithrombin III nor alpha 2M nor alpha 2 antiplasmin but a three fold plasma concentration of C1-inactivator and a 15 fold increase of inter-alpha-trypsin inhibitor. NAPTT (Non Activated Partial Thromboplastin Time) ratios did not seem to be in accordance with either the presence or the absence of contact enzymes. Moreover 0.20 M NaCl appeared as the minimal pre-elution molarity necessary to ensure a NAPTT ratio above thrombogenic values. Molecular alteration of high molecular weight kininogen and C4 was observed and its significance discussed. Complex formation between C1-inactivator and proteases was shown to be another sign of undesirable proteolytic events.

Cardiovascular function in children following bone marrow transplant: a cross-sectional study.

Sixty-three patients who had undergone a BMT at age < or = 18 years were evaluated cross-sectionally to determine cardiac function as well as the long-term prevalence, types, severity, and risk factors of cardiac abnormalities. Patients were > or = 1 year post-BMT and were evaluated by history, resting ECG, echocardiography (ECHO), exercise treadmill test, chest X-ray, pulmonary function tests and review of past cardiac studies. Patients were assigned a New York Heart Association (NYHA) class based on an activity and cardiac symptoms questionnaire. Pretransplant preparative regimens included high-dose cyclophosphamide (CY) and total body/lymphoid irradiation (n = 38), CY in combination with other chemotherapy (n = 22), and other drug combinations (n = 3). Forty patients (63.5%) had received prior anthracyclines (median 307 mg/m2). Patients' ages ranged from 1.9 to 32 years (median 10.9 years) with median follow-up of 3.3 years (range 1-16.3 years). Twenty-six patients (41.3%) had a cardiac abnormality detected at follow-up. In 21 patients the abnormal finding had not been present at the pre-BMT evaluation. Ten patients (16.4%) had resting ECG abnormalities. Left ventricular ejection fraction (LVEF) by ECHO was mildly decreased to 50-54% in three patients and markedly decreased to 40% in one patient. Only one patient (1.7%) developed a mildly abnormal shortening fraction of 27%. All patients with ECHO abnormalities were asymptomatic. Twenty-three of 31 patients > or = 9 years of age (74%) who underwent a treadmill exercise test had a borderline or abnormal response to exercise. There was no correlation between demographic factors, previous therapy, preparative regimen or length of follow-up with the post-BMT ECG, ECHO and treadmill abnormalities. Overall, eight patients (12.7%) were symptomatic and NYHA class II or III, and all had abnormal exercise tests. The presence of symptoms and NYHA class were predictors for oxygen consumption during exercise (P = 0.03 and 0.02, respectively) and tended to predict overall treadmill results also. Late cardiac abnormalities do occur following BMT in childhood and thus, there is a clear need for continued, serial long-term cardiac evaluation in transplant survivors. Evaluations should include exercise stress testing to detect inadequate cardiac output as well as oxygen consumption during exercise.

B cell lymphoproliferative disorders following hematopoietic stem cell transplantation: risk factors, treatment and outcome.

Twenty-six cases of B cell lymphoproliferative disorder (BLPD) were identified among 2395 patients following hematopoietic stem cell transplants (HSCT) for which an overall incidence of BLPD was 1.2%. The true incidence was probably higher, since 9/26 of the diagnoses were made at autopsy. No BLPD was observed following autologous HSCT, so risk factor analyses were confined to the 1542 allogeneic HSCT. Factors assessed were HLA-mismatching (> or = 1 antigen), T cell depletion (TCD), presence of acute GvHD (grades II-IV), donor type (related vs unrelated), age of recipient and donor, and underlying disease. Factors found to be statistically significant included patients transplanted for immune deficiency and CML, donor age > or = 18 years, TCD, and HLA-mismatching, with recipients of combined TCD and HLA-mismatched grafts having the highest incidence. Factors found to be statistically significant in a multiple regression analysis were TCD, donor age and immune deficiency, although 7/8 of the patients with immunodeficiencies and BLPD received a TCD graft from a haploidentical parent. The overall mortality was 92% (24/26). One patient had a spontaneous remission, but subsequently died >1 year later of chronic GVHD. Thirteen patients received therapy for BLPD. Three patients received lymphocyte infusions without response. The only patients with responses and longterm survival received alpha interferon (alphaIFN). Of seven patients treated with alphaIFN there were four responses (one partial and three complete). These data demonstrate that alphaIFN can be an effective agent against BLPD following HSCT, if a timely diagnosis is made.

Outcome of second bone marrow transplantation following a uniform conditioning regimen as therapy for malignant relapse.

Twenty-three second bone marrow transplants (BMT) were performed between October 1987 and January 1994 for patients with malignant relapse following initial BMT. For first BMT, twenty-one of 23 (91%) were conditioned with cyclophosphamide plus total body irradiation. For second BMT, a uniform conditioning regimen consisting of busulfan and cyclophosphamide was used. Eleven patients had chronic myelogenous leukemia, seven acute leukemia, four lymphoma, and one myelodysplastic syndrome. Median patient age at second BMT was 32 years, the median time between first BMT and relapse was 22 months, and the median time to second BMT after relapse was 5 months. The second BMT marrow source included: autologous marrow (1), unrelated donors (4), new matched sibling donors (5) and same matched sibling donors as the first BMT (13). The Kaplan-Meier disease-free survival and survival rates at 3 years were 38 and 43%, respectively (median follow-up of survivors was 45 and 48 months, respectively), and five patients survive disease-free at 4-6 years. Nine of the 13 deaths occurred within 100 days after second BMT; eight had relapsed within 1 year of the first BMT. We conclude that: (1) second BMT can offer durable long-term survival in certain patients, especially those who relapse late after first transplant; (2) busulfan and cyclophosphamide is a suitable conditioning regimen for second BMT.

Heparin and the progressive anti-thrombin activity of alpha 2-macroglobulin.

Interactions between alpha 2-macroglobulin (alpha 2M) and thrombin have been studied by spectroscopic, isotopic and electrophoretic methods in presence or in absence of heparin. It is shown that thrombin binds to alpha 2M in a 1:1 ratio. Fluorescamin labelled heparin of Mr 7 000 interacts with thrombin to form a 2:1 molar complex. This complex does not bind to alpha 2M and is unable to achieve any proteolytic cleavage of this protein. In contrast the interaction of alpha 2M with chymotrypsin is not significantly affected by the mucopolysaccharide. Moreover, heparin is unable to react with alpha 2M bound thrombin.

Inhibition of activated protein C by aprotinin and the use of the insolubilized inhibitor for its purification.

The study of the interaction between activated protein C (APC) and non-plasmatic inhibitors allowed us to demonstrate that aprotinin is a potent competitive inhibitor of APC with a Ki of 1.35 mumol/L. It was possible to adsorb immunopurified protein C (PC) activated by venom activator to insolubilized aprotinin and to recover the active enzyme after elution by HCl 0.1 N or by a chaotropic ion, for example KSCN 3 mol/L. The interaction involved the active-site of the enzyme since PC and DIP-APC did not bind to the matrix. Thus, APC could be purified, after activation, in a one-stage procedure out of a mixture of protein such as a prothrombin complex concentrate.

Properties of a new fibrin glue stable in liquid state.

A pasteurized preparation of fibrin glue composed of two separate stable, liquid components: highly purified human thrombin and fibrinogen concentrate is described. The components are mixed extemporaneously during application. Thrombin was prepared using a prothrombin complex concentrate as starting material which was activated by calcification and then heated in solution during 10 hours at 60 degrees C in the presence of stabilizers. The isolation of thrombin was carried out using a column of benzamidine-Sepharose 6B. The eluate contained thrombin with a high degree of purity (more than 95% assessed by SDS-PAGE) with a specific activity > 2,500 IU/mg protein. The purified liquid thrombin preparation remained stable for at least 6 months. The fibrinogen concentrate was prepared from cryoprecipitate after removal of factor VIII and then virally inactivated by pasteurization in the presence of glucose and sorbitol. After purification the concentrate containing a high level of fibrinogen was formulated with urea 0.5 M or arginine 5% before conditioning. Both components of the fibrin glue kept its biological properties for more than 6 months at +4 degrees C.

Aprotinin is a competitive inhibitor of the factor VIIa-tissue factor complex.

A highly purified preparation of human plasma factor VIIa was submitted to chromogenic assays with S-2288 factors IXa, Xa, activated protein C and thrombin being absent. Factor VIIa alone or in the presence of calcium, kept its activity even in the presence of high concentrations of aprotinin, inhibition appeared only in the presence of a factor VIIa-tissue factor complex. A two-stage amidolytic assay using activation of purified factor X and hydrolysis of S-2765 chromogenic substrate by the generated Xa was used to show a competitive inhibition with a Ki value of 30 microM. Aprotinin had no effect on factor Xa amidolytic activity per se. The factor VIIa-tissue factor complex could be adsorbed to immobilized aprotinin and removed by a chaotropic ion like KSCN 3 M. The assays with the DFP inactivated VIIa-tissue factor complex proved that the interaction involved the active site of factor VIIa. The inhibition of the VIIa-tissue factor complex was demonstrated in a clotting assay using aprotinin enriched normal or factor VIII deficient plasma.

The alpha 2 macroglobulin/thrombin interaction in the presence of hydroxylamine.

The influence of a primary amine, hydroxylamine, on the interaction between alpha 2 macroglobulin (alpha 2M) and thrombin was analyzed by electrophoretic and enzymatic methods. Hydroxylamine (final concentrations 0.01 M and 0.1 M) was added to the alpha 2M solution 3 to 5 min before thrombin. In these conditions hydroxylamine had no direct influence on alpha 2M itself. The inhibition of thrombin activity by alpha 2M was still possible and alpha 2M/thrombin complexes were observed. However the rate of inhibition of the clotting activity of thrombin was diminished in function of the hydroxylamine concentration. The complexes obtained in the absence of the nucleophylic agent were resistant to SDS dissociation, whereas those obtained in the presence of hydroxylamine were dissociated by SDS. In both cases, the amount of alpha 2M polypeptide chains cleaved by thrombin was the same (50%). In conclusion, hydroxylamine does not prevent the formation of alpha 2M/thrombin complexes, but it reduces the covalent binding of the enzyme to the inhibitor in a concentration dependent fashion, leading to the formation of "abnormal" complexes.

A human factor VIIa concentrate and its effects in the hemophilic A dog.

Properties of a new concentrate of FVII/FVIIa, obtained by adsorption onto an inorganic adsorbent followed by a chromatographic step onto Q-Sepharose using a by-product of routine fractionation as starting material, are described. This fraction contains only small amounts of the other components of the prothrombin complex but it is enriched in Proteins C and S. This preparation is essentially free of FVIIICag. It has been submitted to animal experiments including those carried out on normal and hemophilic A dogs. A normalization of the buccal bleeding time was seen after injection of a minimal dose of 4 uFVIIa/kg. No adverse reaction was observed at any dose employed. This concentrate might thus be indicated for the treatment of Haemophilia A patients with inhibitors. Its viral inactivation has been achieved.