The use of shotgun label-free quantitative proteomic mass spectrometry to evaluate the inflammatory response in aqueous humor from horses with uveitis compared to ophthalmologically healthy horses.

OBJECTIVE: The objective of this study was to use shotgun label-free tandem mass spectrometry (LF-MS/MS) to evaluate aqueous humor (AH) from horses with uveitis (UH) compared to ophthalmologically healthy horses (HH). ANIMALS STUDIED: Twelve horses diagnosed with uveitis based on ophthalmic examination and six ophthalmologically healthy horses (postmortem) purchased for teaching purposes. PROCEDURES: All horses received a complete ophthalmic examination and physical exam. Aqueous paracentesis was performed on all horses and AH total protein concentrations were measured with nanodrop (TPn) and refractometry (TPr). AH samples were analyzed with shotgun LF-MS/MS and proteomic data were compared between groups using Wilcoxon rank-sum test. RESULTS: A total of 147 proteins were detected, 11 proteins had higher abundance in UH, and 38 proteins had lower abundance in UH. Proteins with higher abundance included apolipoprotein E, alpha-2-macroglobulin (A2M), alpha-2-HS-glycoprotein, prothrombin, fibrinogen, complement component 4 (C4), joining chain for IgA and IgM, afamin, and amine oxidase. There were positive correlations between TPn (p = .003) and TPr (p = .0001) compared to flare scores. CONCLUSION: Differential abundance of A2M, prothrombin, fibrinogen, and C4 indicate upregulation of the complement and coagulation cascade in equine uveitis. Proinflammatory cytokines and the complement cascade have potential as therapeutic targets for equine uveitis.

COMPARING THE EFFECTIVENESS OF CONCENTRATE OF ALL PROTHROMBIN COMPLEX FACTORS WITH RECOMBINANT HUMAN COAGULATION FACTOR VIIa IN THE TREATMENT OF BLEEDING AFTER CARDIAC SURGERY.

OBJECTIVE: Aim: The authors evaluated the effectiveness of treatment with recombinant human coagulation factor VIIa and concentrate of all prothrombin complex factors in patients with massive postoperative bleeding that could not be controlled with traditional therapy. PATIENTS AND METHODS: Materials and Methods: In the period from 2020 to 2021, recombinant human coagulation factor VIIa was administered to 18 patients after cardiac surgery (group I), while the concentrate of all prothrombin complex factors was administered to 16 patients postoperatively (group II). During this period, 647 patients were operated on. The patients had normal coagulation screening tests (APTT, INR, TT, fibrinogen level, and PLT level) before surgery. Mean blood loss before and after administration of eptacog alfa and the total prothrombin complex concentrate was assessed. The mean dose of eptacog alfa was 30.95 mcg/kg b.w., and the total prothrombin complex factor concentrate dose was 14.17 mcg/kg b.w. After transfusion with red blood cell concentrate, fresh frozen plasma, and platelet concentrate, in the absence of improvement in the dynamics of postoperative drainage, it was decided to include recombinant human coagulation factor VIIa or a concentrate of all prothrombin complex factors in the treatment. RESULTS: Results: After administration of recombinant human coagulation factor VIIa at a dose of 30.95 mcg/kg b.w., bleeding stopped in 12 patients, but the remaining 6 patients required reoperation due to persistently high drainage. The decision to perform a rethoracotomy was made by a team of cardiothoracic surgeons and anesthesiologists, taking into account the dynamics of drainage (bleeding) and the hemodynamic stability of the patient. After the administration of concentrate of all prothrombin complex factors at a dose of 14.17 U/kg b.w., bleeding stopped in 12 patients. Four patients required reoperation due to persistent bleeding. CONCLUSION: Conclusions: Treatment with recombinant human coagulation factor VIIa and concentrate of all prothrombin complex factors is effective and safe for cardiac surgery patients.

Decrease of prothrombin level during thrombolysis in acute myocardium infarction.

Previously, the direct interactions of Bß26-42 fibrin residues with prothrombin were demonstrated. It was also shown that forming prothrombin complexes with E- or DDE-fragments causes non-enzymatic prothrombin activation. The direct measuring of the prothrombin level in the blood plasma of patients with acute myocardial infarction (AMI) allowed us to find a situation where such an activation can occur in vivo. Blood coagulation parameters in the blood plasma of patients with AMI were measured at 2 hours, three days, and seven days after the thrombolysis by streptokinase accompanied with intravenous administration of anticoagulants: unfractionated high molecular weight heparin (HMWH) and low-molecular-weight heparin (LMWH). The prothrombin level in the blood plasma of patients with AMI was normal before thrombolytic therapy and substantially decreased after streptokinase administration. This effect was prominent in the case of concomitant anticoagulant therapy with LMWH and was not observed when HMWH was applied. It can be explained by the fact that LMWH preferentially inhibits factor Xa, while the HMWH is an effective inhibitor of both factor Xa and thrombin. This observation suggested that the prothrombin level decrease was caused by the thrombin-like activity and possible autolysis of prothrombin by thrombin. Also, thrombolytic therapy with streptokinase caused the accumulation of fibrin degradation products (FDPs), some of which were able to bind prothrombin. The dramatic decrease of prothrombin level in the blood plasma of patients with AMI during thrombolysis allowed us to conclude the non-enzymatic prothrombin activation with the following autolysis of prothrombin that contributes to the pathology.

The impact of the approval of prothrombin complex concentrates for vitamin K antagonist-related intracerebral hemorrhage: A retrospective study.

OBJECTIVES: This study aimed to determine the impact of the approval of prothrombin complex concentrates on the treatment of vitamin K antagonist-related intracerebral hemorrhage. MATERIALS AND METHODS: We retrospectively studied all patients with vitamin K antagonist-related intracerebral hemorrhage treated with prothrombin complex concentrate at our institutes between January 2010 and June 2021. Before approval, prothrombin complex concentrate was administered as either 500 or 1000 IU at the physician's discretion (previous dose group). After approval, we adopted the manufacturer's recommended regimen (recommended dose group). The primary outcome was post-administration international normalized ratio. Secondary outcomes were the amount of prothrombin complex concentrate administered and proportion of post-administration international normalized ratio <1.5, hematoma expansion, thrombotic events within 30 days, modified Rankin scale 0-3 at discharge, and in-hospital mortality. RESULTS: Thirty-two and 19 patients in the previous and recommended dose groups, respectively, were included. The post-administration international normalized ratio significantly differed between groups. The prothrombin complex concentrate dose and proportion of patients achieving post-administration international normalized ratio <1.5 were significantly higher in the recommended dose group than in the previous dose group (1500 IU vs. 500 IU, p<0.001 and 100% vs. 68%, p = 0.008). The proportions of hematoma expansion, thromboembolic events, modified Rankin scale 0-3, and mortality did not differ between groups. CONCLUSION: After prothrombin complex concentrate approval, prothrombin time-international normalized ratio correction was more effective with a significant increase in the prothrombin complex concentrates dose for vitamin K antagonist-associated intracerebral hemorrhage; however, there was no apparent difference in clinical outcomes.

Autoimmune Hepatitis with Acute Presentation: Clinical, Biochemical, and Histological Features of 126 Patients.

Introduction: Autoimmune hepatitis (AIH) is a chronic liver disease with a relevant inflammatory component and an unknown etiology. Evidence for clinical characteristics and risk factors in large cohorts of patients with acute AIH (AAIH) is lacking. We clinically characterized patients with AAIH, the prevalence of a combined adverse outcome (death or liver transplantation (LT)), and its risk factors. Methods: A retrospective study of adult patients diagnosed with AAIH at three centers (Santiago, Chile; 2000-2018) was conducted. Clinical and laboratory characteristics were obtained. A liver biopsy was performed for all patients. Descriptive statistics and logistic regression models were used. Results: A total of 126 patients were admitted; 77% were female, 33 (26.2%) had a severe presentation, and 14 (11.1%) had a fulminant presentation. Overall, 24 patients (19.0%) lacked typical autoantibodies, and 26.2% had immunoglobulin G levels in the normal range. The most frequent histological findings were plasma cells (86.5%), interface hepatitis (81.7%), and chronic hepatitis (81.0%). Rosettes were uncommon (35.6%). Advanced fibrosis was present in 27% of patients. Combined adverse outcomes occurred in 7.9% of cases, all fulminant with histological cholestasis. Alkaline phosphatase, bilirubin, and prothrombin less than 50% were independent risk factors for in-hospital death or LT (p value <0.05). Although corticosteroid treatment was associated with better outcomes (OR 0.095, p value = 0.013), more severe patients were less likely to receive this therapy. Discussion. In this large cohort of patients with AAIH, clinical characteristics differ from those reported in patients with chronic AIH. Fulminant hepatitis, histological cholestasis, alkaline phosphatase, bilirubin, and prothrombin were associated with death/LT.

Lupus Anticoagulant-Hypoprothrombinemia Syndrome and Pseudotumor Cerebri as an Initial Presentation of Systemic Lupus Erythematosus in a 16-Year-Old Male Patient: A Case Report and Literature Review.

BACKGROUND Lupus anticoagulant-hypoprothrombinemia syndrome (LAHPS) is an exceptionally rare disease caused by prothrombin antibodies, resulting in reduced factor II levels. This disease can present with significant bleeding and is usually associated with autoimmune disorders, particularly systemic lupus erythematosus (SLE). There are currently no guidelines for the treatment of LAHPS, and corticosteroids remain the criterion standard therapy. Pseudotumor cerebri is a disease that involves an idiopathic rise in intracranial pressure in association with papilledema. The coexistence of pseudotumor cerebri with SLE is rare, with an overall incidence of 0.7%. CASE REPORT A 16-year-old male initially presented to our hospital with nausea, headaches, and decreased visual acuity. He was diagnosed with pseudotumor cerebri based on the findings of papilledema and a raised opening pressure on lumbar puncture. Three months later, he presented with macroscopic hematuria and persistent epistaxis. Further investigation revealed a prolonged activated partial thromboplastin time and prothrombin time, along with positive LA and reduced Factor II levels, resulting in a diagnosis of LAHPS. The patient received a dose of 1 mg/kg/day of prednisolone along with hydroxychloroquine, and he had a complete recovery with cessation of bleeding and normalization of laboratory parameters. CONCLUSIONS We are reporting a case of pseudotumor cerebri with a further presentation of LAHPS in a patient found to have SLE. As both associations are rare in the presence of SLE, it is vital to recognize them early to initiate adequate management and intervention to avoid life-threatening complications.

Scurvy.

Dear Editor, Scurvy is a nutritional disorder which can develop after prolonged (>1-3 months) severe vitamin C deficiency. Vitamin C is a cofactor in several enzyme reactions involved in collagen synthesis. The defect in collagen causes blood vessel fragility, poor wound healing, mucocutaneous bleedings, hair abnormalities, bone pains, and joint contractures due to periosteal and intraarticular bleeding (1,2). Risk factors for scurvy development are undernutrition, low socioeconomic status, older age, male sex, alcoholism, tobacco smoking, and severe psychiatric illnesses (1-3). The required daily intake for vitamin C is ~60 mg, and this amount of vitamin C can be found in only one medium-sized orange. For this reason, the disease is rarely encountered in developed countries and is often underrecognized by healthcare personnel. Herein, we present an illustrative case of scurvy in order to raise the awareness of this disorder. A 61-year-old Caucasian man was admitted to hospital due to fatigue, hypotension (80/50 mmHg), severe normocytic anemia (hemoglobin 76 g/L), kidney failure (estimated glomerular filtration rate of 6 mL/min/1.73m2) and mild elevation in C-reactive protein (30.9 mg/L). Prior medical history included radical cystoprostatectomy with an ileal conduit performed eight years ago due to a bladder tumor and moderate chronic kidney disease with recurrent urinary tract infections. The patient was also an alcoholic and tobacco smoker, with a very low-income and a poor diet. He did not use any medications. Heteroanamnestically, the current clinical state had developed slowly over several weeks. At admission, the patient was afebrile, lethargic, malnourished, and immobile due to generalized weakness, bone pains, and hip and knee contractures. He had generalized edema, mostly related to kidney failure, as well as severe hypoalbuminemia (serum albumin 19 g/L). There were multiple ecchymoses (Figure 1, a) and perifollicular bleedings (Figure 1, b) in the skin. The teeth were defective, and the patient's facial hair had a "corkscrew" appearance (Figure 1, c). The platelet count was normal, as was the serum fibrinogen level and the prothrombin- and activated partial thromboplastin times. Vancomycin-resistant Enterococcus faecium and multi-drug-resistant Acinetobacter baumanii were isolated from the urine. Therefore, hemodialysis, linezolid, and colistin were started. However, the patient continued to be lethargic, immobile, and with prominent skin bleeding. Medical workup excluded the possibility of an underlying malignancy or an autoimmune disorder. Finally, scurvy was suspected and 500 mg daily of oral vitamin C was introduced into therapy. In the following two weeks, the general condition of the patient significantly improved and he was discharged from the hospital in good condition - mobile and with complete resolution of skin lesions (Figure 1, d and e). Three months later, the patient was still under maintenance hemodialysis and had mild anemia (hemoglobin 123 g/L). Interestingly, scurvy was the first disease in the history of medicine for which a randomized trial found a cure (4). The differential diagnosis of scurvy includes skin infections, hematologic disorders, collagen vascular disorders, and anticoagulant/antiplatelet side-effects (1). Pathognomonic skin findings which may help raise suspicion of scurvy are perifollicular bleedings and "corkscrew" hair. Notably, laboratory testing for vitamin C concentration is not necessary to confirm scurvy as it tends to reflect recent dietary intake of vitamin C (2). Nevertheless, it may be useful to identify less typical cases (2). In our case, rapid clinical improvement with the resolution of skin lesions and joint contractures after the introduction of vitamin C confirmed the clinical diagnosis of scurvy. Additionally, vitamin C deficiency could be, at least partly (besides kidney failure and acute infection), responsible for severe anemia at disease presentation (5). This case serves to remind clinicians not to forget scurvy when treating patients at risk for vitamin C deficiency who present with fatigue, anemia, bone pains, and unexplained mucocutaneous bleedings. In suspected cases, vitamin C should be administered without hesitation.

Control of hippocampal prothrombin kringle-2 (pKr-2) expression reduces neurotoxic symptoms in five familial Alzheimer's disease mice.

BACKGROUND AND PURPOSE: There is a scarcity of information regarding the role of prothrombin kringle-2 (pKr-2), which can be generated by active thrombin, in hippocampal neurodegeneration and Alzheimer's disease (AD). EXPERIMENTAL APPROACH: To assess the role of pKr-2 in association with the neurotoxic symptoms of AD, we determined pKr-2 protein levels in post-mortem hippocampal tissues of patients with AD and the hippocampi of five familial AD (5XFAD) mice compared with those of age-matched controls and wild-type (WT) mice, respectively. In addition, we investigated whether the hippocampal neurodegeneration and object memory impairments shown in 5XFAD mice were mediated by changes to pKr-2 up-regulation. KEY RESULTS: Our results demonstrated that pKr-2 was up-regulated in the hippocampi of patients with AD and 5XFAD mice, but was not associated with amyloid-ß aggregation in 5XFAD mice. The up-regulation of pKr-2 expression was inhibited by preservation of the blood-brain barrier (BBB) via addition of caffeine to their water supply or by treatment with rivaroxaban, an inhibitor of factor Xa that is associated with thrombin production. Moreover, the prevention of up-regulation of pKr-2 expression reduced neurotoxic symptoms, such as hippocampal neurodegeneration and object recognition decline due to neurotoxic inflammatory responses in 5XFAD mice. CONCLUSION AND IMPLICATIONS: We identified a novel pathological mechanism of AD mediated by abnormal accumulation of pKr-2, which functions as an important pathogenic factor in the adult brain via blood brain barrier (BBB) breakdown. Thus, pKr-2 represents a novel target for AD therapeutic strategies and those for related conditions.

Retrospective Comparison of Andexanet Alfa and 4-Factor Prothrombin Complex for Reversal of Factor Xa-Inhibitor Related Bleeding.

The aim of this retrospective study was to compare andexanet alfa and 4-factor prothrombin complex (4F-PCC) for reversal of factor Xa (FXa)-inhibitor bleeding. Patients that received andexanet alfa for reversal were included. An equivalent number of patients administered 4F-PCC for FXa-inhibitor bleeding were randomly selected as historical controls. The primary outcome was effective hemostasis achievement within 12 h, defined using ANNEXA-4 criteria. Thromboembolic events and mortality within 30 days were also evaluated. A total of 32 patients were included. Baseline characteristics were not statistically different between andexanet alfa (n = 16) and 4F-PCC (n = 16). Intracranial bleeding was the primary reversal indication in 43.8% versus 62.5% of patients, respectively. Effective hemostasis was reached in 75.0% of andexanet alfa patients compared to 62.5% of 4F-PCC patients (P = .70). Thromboembolic events occurred in 4 (25.0%) patients and 3 (18.8%) patients, respectively (P = .99). Mortality incidence was 12.5% and 31.3%, respectively (P = .39). Andexanet alfa and 4F-PCC attained hemostasis in a majority of patients. A high, but a similar rate of thromboembolic events was seen with both treatments. Prospective studies are needed to elucidate comparative risks and benefits of the 2 agents.

[Possibility of using coagulation factor â ¡ and factor â © for warfarin monitoring in Chinese pulmonary embolism patients].

Objective: To explore the possibility of using coagulation factor Ⅱ and Ⅹ (FⅡ and FⅩ) for warfarin monitoring among Chinese pulmonary embolism patients. Methods: Blood samples were collected from pulmonary embolism patients who were taking warfarin as anticoagulant and who were from Peking Union Medical Collaege Hospital during Mar 2016 and Oct 2018. Activity of coagulation factor Ⅱ/Ⅹ and International Normalized Ratio (INR) level were detected. Correction analysis was used to investigate the relationship between activity of coagulation factor Ⅱ/Ⅹ and INR. Receiver Operating Characteristic (ROC) curve was used to analyze the diagnostic ability of FⅡ and FⅩ. Results: A total of 157 blood samples were collected in this research. When 1.5≤INR≤3.0, FⅡ (r=-0.768, P<0.001) and FⅩ(r=-0.690, P<0.001) were in inverse correlations with INR. Area under ROC curve (AUC) for FⅡ and FⅩ was 0.961 and 0.965 (P<0.001) when we used INR<2.0 as the criteria of anticoagulant inadequacy. AUC of ROC for FⅡ and FⅩ was 0.885 and 0.890 (P<0.001) when we used INR≤3.0 as the criteria of not over-anticoagulation. Conclusion: FⅡ and FⅩ activity can be used as the therapeutic markers of warfarin in Chinese pulmonary embolism patients.

Recombinant human prothrombin (MEDI8111) combined with fibrinogen dose-dependently improved survival time and reduced blood loss in a porcine model of dilutional coagulopathy with uncontrolled bleeding.

: Uncontrolled bleeding due to trauma and coagulopathy is an area with high unmet medical need and high mortality rate. Treatment recommendations focus on transfusion of blood components while optimal therapy to improve coagulation remains to be established. The haemostatic effect of 2, 4 and 8 mg/kg recombinant prothrombin (MEDI8111) co-administered with 100 mg/kg fibrinogen (n = 7-8) was investigated in a porcine model of dilutional coagulopathy with uncontrolled bleeding. Vehicle (n = 11), fibrinogen alone (100  mg/kg , n = 15) were included as controls. Dilutional coagulopathy was induced by replacing ∼75% of the blood volume with hydroxyethyl starch and a standardized liver incision was made followed by intravenous administration of study compounds. Survival time and blood loss were determined up to 120 min after liver incision. Rotational thromboelastometry (ROTEM EXTEM), prothrombin time (PT), thrombin--antithrombin complex and thrombin generation were measured at baseline, after dilution and 10, 40, 80 and 120 min after compound administration. Administration of MEDI8111+fibrinogen improved haemostasis, decreased blood loss and dose-dependently improved survival time compared to fibrinogen. All pigs receiving a dose of 8 mg/kg MEDI8111+fibrinogen, which restored normal prothrombin concentration, survived to the end of the experiment with close to normal haemostasis as measured by PT and ROTEM EXTEM CT. Administration of fibrinogen and MEDI8111 was sufficient to improve survival time and haemostasis in severely coagulopathic pigs. The dose-dependent haemostatic improvement observed with MEDI8111 administration suggests that prothrombin concentration was rate limiting for coagulation.

The use of new procoagulants in blunt and penetrating trauma.

PURPOSE OF REVIEW: Uncontrolled bleeding in trauma secondary to a combination of surgical bleeding and trauma-induced complex coagulopathy is a leading cause of death. Prothrombin complex concentrates (PCCs), recombinant activated factor seven (rFVIIa) and recombinant human prothrombin act as procoagulants by increasing thrombin generation and fibrinogen concentrate aids stable clot formation. This review summarizes the current evidence for procoagulant use in the management of bleeding in trauma, and data and evidence gaps for routine clinical use. RECENT FINDINGS: Retrospective and prospective studies of PCCs (±fibrinogen concentrate) have demonstrated a decreased time to correction of trauma coagulopathy and decreased red cell transfusion with no obvious effect on mortality or thromboembolic outcomes. PCCs in a porcine model of dilutional coagulopathy demonstrated a sustained increase in thrombin generation, unlike recombinant human prothrombin which showed a transient increase and has been studied only in animals. In other retrospective studies, there is a suggestion that lower doses of PCCs may be effective in the setting of acquired coagulopathy. SUMMARY: There is increasing evidence that early correction of coagulopathy has survival benefits, and the use of procoagulants as first-line therapy has the potential benefit of rapid access and timely treatment. This requires confirmation in prospective studies.

Fixed-Dose Four-Factor Prothrombin Complex Concentrate for Vitamin K Antagonist Reversal: Does One Dose Fit All?

Four-factor prothrombin complex concentrate (4F-PCC) has emerged as the preferred option for emergent reversal of vitamin K antagonists (VKAs); however, the optimal dosing strategy is unknown. Although several studies have attempted to determine the optimal dose of 4F-PCC using a variety of dosing regimens, no dosing strategy has been found to be superior. Many of these studies have evaluated a low, fixed dose of 4F-PCC rather than individualized dosing as recommended in product labeling. The purpose of this review was to evaluate the efficacy and safety of various fixed-dose strategies of 4F-PCC for emergent VKA reversal and to assess limitations of the existing literature. A search of the PubMed database was performed from the earliest available date through 2018 for relevant articles describing fixed-dose 4F-PCC for VKA reversal. Reference lists of relevant articles were also manually reviewed. Most currently available studies are primarily observational and heterogeneous in design. A very low fixed dose of 500 IU is likely inadequate for successful VKA reversal, but increased fixed doses of 1000-1500 IU have found some degree of success and may be considered for VKA reversal. However, many of these studies consistently identified a trend toward international normalized ratio (INR) reversal failure in patients presenting with high baseline INR values or intracranial hemorrhage, suggesting that higher 4F-PCC doses are needed in these patients. Available studies are underpowered to determine whether a dose-dependent association with thrombotic risk exists. Additional large, randomized studies are needed to determine the optimal dosing strategy and ascertain the role for fixed-dose 4F-PCC.

aPCC vs. rFVIIa for the treatment of bleeding in patients with acquired haemophilia - a cost-effectiveness model.

BACKGROUND: Acquired haemophilia A (AHA) is an autoimmune bleeding disorder with significant morbidity and mortality. Bleeding AHA patients with high titre inhibitors can be treated with either activated prothrombin complex concentrate (aPCC) or recombinant activated factor VII (rFVIIa). Given that both replacement therapies have inherent benefits and limitations, a cost-effectiveness analysis (CEA) was performed in this population to compare rFVIIa with aPCC. METHODS: In high-titered AHA patients with bleeding treated with either aPCC or rFVIIa, during a 5-day study period, a Markov model was developed such that these patients were transitioned into four different health states: (1) continuous bleeding, (2) thrombosis, (3) stop bleeding and (4) death, with states (2), (3) and (4) modelled as absorbing states. Model parameters, including probabilities, health utility index and costs, were gathered from the medical literature, except for the costs of aPCC and rFVIIa, which were obtained from our institutional data. RESULTS: During the 5-day period, the total treatment cost of rFVIIa was substantially more than the cost of aPCC ($13 635 vs. $1741). The average quality-adjusted life days (QALDs) gained for rFVIIa were slightly lower compared to aPCC (4·08 vs. 4·09). Overall, aPCC prevailed over rFVIIa. Sensitivity analysis confirmed the robustness of the model across tested ranges of all input variables. CONCLUSION: In high-titered AHA patients with bleeding, aPCC is a cost-effective treatment option when compared to rFVIIa. Thus, aPCC may be considered in these patients, if available, and provided there is no clinical contraindication.

Activated Prothrombin Complex Concentrate Versus 4-Factor Prothrombin Complex Concentrate for Vitamin K-Antagonist Reversal.

OBJECTIVES: To compare the international normalized ratio normalization efficacy of activated prothrombin complex concentrates and 4-factor prothrombin complex concentrates and to evaluate the thrombotic complications in patients treated with these products for warfarin-associated hemorrhage. DESIGN: Retrospective, Multicenter Cohort. SETTING: Large, Community, Teaching Hospital. PATIENTS: Patients greater than 18 years old and received either activated prothrombin complex concentrate or 4-factor prothrombin complex concentrate for the treatment of warfarin-associated hemorrhage. We excluded those patients who received either agent for an indication other than warfarin-associated hemorrhage, pregnant, had a baseline international normalized ratio of less than 2, received a massive transfusion as defined by hospital protocol, received plasma for treatment of warfarin-associated hemorrhage, or were treated for an acute warfarin ingestion. INTERVENTIONS: Patients in the activated prothrombin complex concentrate group (enrolled from one hospital) with an international normalized ratio of less than 5 received 500 IU and those with an international normalized ratio greater than 5 received 1,000 IU. Patients in the 4-factor prothrombin complex concentrate (enrolled from a separate hospital) group received the Food and Drug Administration approved dosing algorithm. MEASUREMENTS AND MAIN RESULTS: A total of 158 patients were included in the final analysis (activated prothrombin complex concentrate = 118; 4-factor prothrombin complex concentrate = 40). Those in the 4-factor prothrombin complex concentrate group had a higher pretreatment international normalized ratio (2.7 ± 1.8 vs 3.5 ± 2.9; p = 0.0164). However, the posttreatment international normalized ratio was similar between the groups. In addition, even when controlling for differences in the pretreatment international normalized ratio, there was no difference in the ability to achieve a posttreatment international normalized ratio of less than 1.4 (odds ratio, 0.753 [95% CI, 0.637-0.890]; p = 0.0009). Those in the activated prothrombin complex concentrate group did have higher odds of achieving a posttreatment international normalized ratio of less than 1.2 (odds ratio, 3.23 [95% CI, 1.34-7.81]; p = 0.0088). There was only one posttreatment thrombotic complication reported. CONCLUSIONS: A low, fixed dose of activated prothrombin complex concentrate was as effective as standard dose 4-factor prothrombin complex concentrate for normalization of international normalized ratio. In addition, we did not see an increase in thrombotic events.

Survival models and health sequences.

Survival studies often generate not only a survival time for each patient but also a sequence of health measurements at annual or semi-annual check-ups while the patient remains alive. Such a sequence of random length accompanied by a survival time is called a survival process. Robust health is ordinarily associated with longer survival, so the two parts of a survival process cannot be assumed independent. This paper is concerned with a general technique-reverse alignment-for constructing statistical models for survival processes, here termed revival models. A revival model is a regression model in the sense that it incorporates covariate and treatment effects into both the distribution of survival times and the joint distribution of health outcomes. The revival model also determines a conditional survival distribution given the observed history, which describes how the subsequent survival distribution is determined by the observed progression of health outcomes.

In vitro exploration of latent prothrombin mutants conveying antithrombin resistance.

INTRODUCTION: Antithrombin resistance (ATR) prothrombinemia is an inherited thrombophilic disorder caused by missense mutations in prothrombin gene (F2) at Arg596 of the sodium-binding region. Previously, prothrombin mutants Yukuhashi (Arg596Leu), Belgrade (Arg596Gln), and Padua 2 (Arg596Trp) were reported as ATR-prothrombins possessing a risk of familial venous thrombosis. To identify additional F2 mutations causing the ATR-phenotype, we investigated the coagulant properties of recombinant prothrombins mutated at amino acid residues within the sodium-binding region by single nucleotide substitutions (Thr540, Arg541, Glu592, and Lys599). MATERIALS AND METHODS: We constructed expression vectors of prothrombin mutants, established stably transfected HEK293 cells, and isolated the recombinant prothrombin proteins. We evaluated procoagulant activity and ATR-phenotypes of those mutants in reconstituted plasma by mixing with prothrombin deficient plasma. RESULTS: The secreted quantity of all prothrombin mutants was the same as that of the wild-type prothrombin. Procoagulant activity of each mutant varied from 1.7% to 79.5% in a one-stage clotting assay and from 2.0% to 104.5% in a two-stage chromogenic assay. Most prothrombin mutants tested presented with a severe ATR-phenotype. To estimate the thrombosis risk of these mutations, we determined the residual clotting activity (RCA) after 30min inactivation with antithrombin. RCA scores, normalized to the wild-type, revealed that prothrombin mutants Lys599Arg (5.35) and Glu592Gln (4.71) had high scores, which were comparable with prothrombins Yukuhashi (4.36) and Belgrade (5.19). CONCLUSIONS: Mutation of prothrombin at the sodium-binding site caused ATR-phenotypes. Of those tested, Lys599Arg and Glu592Gln may possess a thrombosis risk as large as the known pathogenic prothrombins Yukuhashi and Belgrade.