Lanthanide chloride clusters, LnCl, = 1-6: an ion mobility and DFT study of isomeric structures and interconversion timescales.

Ion mobility spectrometry (IMS) (also including IMS-IMS measurements) as well as DFT calculations have been used to study isomer distributions and isomer interconversion in a range of electrospray-generated lanthanide chloride cluster anions, LnCl (where = 1-6, and Ln corresponds to the 15 lanthanide elements (except for radioactive Pm)). Where measurement and structural rearrangement timescales allow, we obtain almost quantitative agreement between experiment and theory thus confirming isomer predictions and reproducing isomer intensity ratios. LnCl structures reflect strong ionic bonding with limited directionality.

The in vitro cross-reactivity and blood coagulation potential of recombinant porcine factor VIII in Japanese patients with acquired hemophilia A.

Recombinant porcine factor VIII (rpFVIII) is a hemostatic agent for acquired hemophilia A (AHA). Cross-reaction of auto-antibodies against rpFVIII has been reported, although no data are available in Japanese patients. This study investigated the cross-reactivity and coagulation potential of rpFVIII in plasma samples from Japanese patients with AHA.

Factor X consumption attenuates the coagulation effect of emicizumab: a case of severe hemophilia A treated with emicizumab and factor VIII-bypassing agents.

In patients with hemophilia A with inhibitor (PwHA-I), emicizumab drastically reduces bleeding events. However, few studies have investigated the behavior and effects of factor X (FX) in patients who require intensive treatment with factor VIII-bypassing agents (BPA) and emicizumab. A 59-year-old man with HA-I receiving emicizumab prophylaxis was admitted to our hospital because of acute gangrenous cholecystitis.

Activated protein C resistance in the copresence of emicizumab and activated prothrombin complex concentrates.

Background: Venous thromboembolic events have been reported in persons with hemophilia A who received emicizumab and activated prothrombin complex concentrate (APCC) concomitantly, but the relevant mechanism(s) remains unclear. We speculated that activated protein C (APC) and antithrombin (AT) resistance might be associated with these adverse events.

Objectives: To investigate APC and AT resistance in factor (F)VIII-deficient (FVIIIdef) plasma in the presence of emicizumab and APCC.

ROTEM could be useful for lupus anticoagulant hypoprothrombinemia syndrome.

Background: Lupus anticoagulant-hypoprothrombinemia syndrome (LAHPS) is a rare disease caused by acquired factor II (FII) deficiency and lupus anticoagulant. Patients with LAHPS typically present with thrombosis and bleeding. However, little information is available on the evaluation of coagulation potential in patients with LAHPS.

Additional Factor X Enhances Emicizumab-Driven Coagulation Function in Patients with Hemophilia A and Hemophilia A Mice.

Background:  Bypassing agents are used for breakthrough bleedings in patients with hemophilia A with inhibitor (PwHAwI) receiving emicizumab prophylaxis. Previous study demonstrated a weak binding affinity between emicizumab and factor (F)X ( ; 1.85 μM), and that this value was much greater than the plasma FX concentration (∼130 nM).

NXT007-mediated hemostatic potential is suppressed by activated protein C-catalyzed inactivation of activated factor V.

Background: Activated protein C (APC) inactivates activated factor (F) V (FVa) and FVIIIa. NXT007, an emicizumab-based engineered therapeutic bispecific antibody, enhances the coagulation potential of FVIII-deficient plasma (FVIIIdef-plasma) to near normal levels. However, little is known about the effect of APC-induced inactivation in NXT007-mediated hemostatic function.

Hybrid human-porcine factor VIII proteins partially escape the inhibitory effects of anti-factor VIII inhibitor alloantibodies having A2 or C2 domain specificity.

Introduction: Porcine factor (pF)VIII has low cross-reactivity with anti-human (h)FVIII inhibitor alloantibodies. Clinical trials of pFVIII in congenital haemophilia A patients with inhibitor (PwHA-I) are in progress. Most polyclonal anti-hFVIII inhibitors recognize its A2 and/or C2 domain(s), and recombinant human-porcine hybrid (hp)FVIII proteins may escape neutralization by these inhibitors.

The role of proteolytic cleavage at Arg and Arg of the A1 domain in factor VIIa/tissue factor-catalyzed reactions of B domain-deleted factor VIII.

Background: We previously demonstrated that factor (F)VIII was rapidly activated through proteolytic cleavage at Arg and Arg by activated FVII (FVIIa)/tissue factor (TF) in very early coagulation phase, followed by inactivation by cleavage at Arg. The influence of the absence of FVIII B domain in this series of FVIIa/TF-catalyzed reaction remains unclear, however.

Aim: To examine the FVIIa/TF-catalyzed reaction of B domain-deleted (BDD-)FVIII.

Longitudinal dynamic changes in factor VIII inhibitor titers in patients with hemophilia A and inhibitors receiving emicizumab prophylaxis.

Emicizumab prophylaxis dramatically reduces bleeding events in patients with hemophilia A (PwHA) with or without factor VIII (FVIII) inhibitors. However, long-term dynamic changes in FVIII inhibitor titers during emicizumab prophylaxis remain to be investigated. We conducted a retrospective follow-up study of FVIII inhibitor titers after initiation of emicizumab prophylaxis in 25 PwHA carrying current or historical FVIII inhibitors.

Size-Dependent Geometrical Structures of Platinum Oxide Cluster Cations Studied by Ion Mobility-Mass Spectrometry.

Structures of platinum oxide cluster cations (PtO) were studied by ion mobility-mass spectrometry in combination with theoretical calculations. Structures of oxygen-equivalent PtO ( = 3-7) clusters were discussed from the comparison between their collision cross sections (CCSs) obtained by mobility measurement and simulated CCSs of their structural candidates from structural optimization calculations. Assigned structures of PtO were found to be composed of Pt frameworks and bridging O atoms, which follows the previous theoretical prediction on the neutral clusters.

The spleen is the major site for the development and expansion of inhibitor producing-cells in hemophilia A mice upon FVIII infusion developing high-titer inhibitor.

Background: Hemophilia A (HA) is a hereditary bleeding disorder caused by defects in endogenous factor (F)VIII. Approximately 30 % of patients with severe HA treated with FVIII develop neutralizing antibodies (inhibitors) against FVIII, which render the therapy ineffective. The managements of HA patients with high-titter inhibitors are especially challenging.

Impaired factor V-related anticoagulant mechanisms and deep vein thrombosis associated with A2086D and W1920R mutations.

Factor V (FV) plays pivotal roles in both procoagulant and anticoagulant mechanisms. Genetic mutations, FV-W1920R (FVNara) and FV-A2086D (FVBesançon), in the C1 and C2 domains of FV light chain, respectively, seem to be associated with deep vein thrombosis. However, the detailed mechanism(s) through which these mutations are linked to thrombophilia remains to be fully explored.

High levels of factor VIII activity in patients with acquired hemophilia A in remission are associated with unusually low coagulation potentials.

Background: Elevated factor VIII activity (FVIII:C) is often observed in patients with acquired hemophilia A (PwAHA) in remission. However, comprehensive coagulation potentials in this patient group remain to be investigated.

Aim: To evaluate comprehensive coagulation potentials in PwAHA.

Two pediatric cases of severe hemophilia A in which emicizumab prophylaxis failed to prevent traumatic extra-articular hemorrhage.

Emicizumab reduces bleeding episodes in patients with severe hemophilia A (PwHA). Little information is available on hemostatic management of severe traumatic hemorrhages in emicizumab-treated pediatric PwHA. We assessed therapeutic efficacy and global coagulation potentials in two pediatric cases of emicizumab-treated pediatric PwHA with intracranial or retroperitoneal/iliopsoas hemorrhage.

Factor VIII mutated with Lys1813Ala within the factor IXa-binding region enhances intrinsic coagulation potential.

Factor VIII (FVIII) functions as a cofactor of FIXa for FX activation in the intrinsic tenase complex. The 1811-1818 region in the FVIII A3 domain was observed to contribute to FIXa binding, and the K1813A/K1818A mutant increased the binding affinity for FIXa. The current study aims to identify mutated FVIII protein(s) that increase FVIIIa cofactor activity in the 1811-1818 region.