Factor X is one of the vitamin-K-dependent serine proteases. As a result of its position at the convergence of the intrinsic and extrinsic pathways of the clotting cascade, it plays a crucial role in blood coagulation. Factor X interacts with components of both pathways of coagulation, leading to its activation and the formation of the prothrombinase complex. The gene for factor X has been cloned and sequenced and maps to the long arm of chromosome 13, approximately 2.8 kb downstream of the factor VII gene. Each of the exons of factor X encodes a specific functional domain within the protein. In terms of its gene structure and amino acid sequence, factor X shows significant homology with other vitamin-K-dependent clotting factors, suggesting an origin in some common ancestral protein. Factor X deficiency is one of the rarest of the inherited coagulation disorders. Such deficiencies are inherited in an autosomal recessive manner and are characterized by a variable bleeding tendency. In its homozygous form, factor X deficiency has an estimated prevalence of 1:500 000 but in its heterozygous form it has an estimated frequency of ∼1:500 although affected individuals are often clinically asymptomatic. Acquired deficiencies of factor X are uncommon and in isolation are seen most frequently in patients with amyloidosis and in association with upper respiratory tract infections. Treatment of the deficiency state involves factor X replacement with either fresh frozen plasma or prothrombin complex concentrates. However, the latter may be associated with an increased risk of thrombosis.

We report 18 cases of pain and tenderness in the mid-part of the patellar ligament in athletes. The condition may be disabling, but it responds to surgery. Ultrasound and CI scans were positive in all 17 confirmed cases, but ultrasound gave a better distinction between

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We report the clinical experience of a large Haemophilia Centre and Haemostasis Unit in reversing oral anticoagulation (OAC) using clotting factor concentrates. This is a retrospective study extending over 2 years (January 1996-December 1997). Reversal was performed using a combination of factor IX and factor VII concentrates administered by intravenous infusion. in a dose varying between 12 i.u./kg and 50 i.u./kg. We identified 20 episodes of OAC reversal in 18 patients, with a prevalence of 10 reversal episodes/1000 OAC patients/year. The median age was 77 years old (range 53-92 years). Indications for OAC reversal were divided into major bleeds (muscle haematoma [9], haematuria [3], subarachnoid haemorrhage [1], oesophageal bleeding [1], haemoptysis [1], haemarthrosis [1]); minor bleeds (extensive bruising [9], epistaxis [3], oral cavity bleeding [1]); and emergency invasive investigation (2). Pre-reversal, the international normalized ration (INR) was greater than 6.0 in 15/18 patients. Post-infusion. there was an immediate reduction in the INR towards normal (mean 1.3; range 1.1-2.3). There were no thrombotic complications or other adverse effects. The median use of factor 9 A concentrate was 2300 units/patient (range 570-4195), at a cost of 645 Pounds/patient and for factor VII concentrate 2200 units/patient (range 815-3630), at a cost of 664 Pounds/patient. Clotting factor concentrates provide a safe, rapid and effective means for OAC reversal and although expensive it is the treatment of choice in the over anticoagulated, bleeding patient.

Early pregnancy is maintained in ruminants through the actions of conceptus-derived interferon (IFN)-tau on the endometrium. IFN-tau alters uterine release of PGF2", which results in rescue of the corpus luteum and continued release of progesterone. The mechanism of action of IFN-tau includes inhibition of oestradiol receptors, consequent reduction in oxytocin receptors, activation of a cyclooxygenase inhibitor, and a shift in the PGs to favour PGE2 over PGF,,,. IFN-tau also induces several endometrial proteins that may be critical for survival of the developing embryo. One endometrial protein induced by pregnancy and IFN-tau has been identified as bovine granulocyte chemotactic protein-2 (bGCP-2). This chemotactic cytokine (chemokine) has been used as a marker to delineate IFN-tau from IFN-alpha responses in the endometrium. A second protein, called ubiquitin cross-reactive protein (UCRP), resembles a tandem ubiquitin repeat. UCRP becomes conjugated to cytosolic endometrial proteins in response to IFN-tau and pregnancy. Proteins conjugated to UCRP are either modulated or targeted for processing through the proteasome. The action of IFN-tau is mediated by induction of signal transducer and activator of transcription 1 (STAT-1), STAT-2 and interferon regulatory factor 1 (IRF-1) transcription factors. Induction of these transcription factors, the alpha chemokines and UCRP is the prelude to maternal recognition of pregnancy in ruminants.