Tests of Light-Lepton Universality in Angular Asymmetries of B^{0}→D^{*-}ℓν Decays

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189  fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.

Precise Measurement of the D_{s}^{+} Lifetime at Belle II

We measure the lifetime of the D_{s}^{+} meson using a data sample of 207  fb^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×10^{3} D_{s}^{+}→ϕπ^{+} decays. Our result is τ_{D_{s}^{+}}=(499.5±1.7±0.9)  fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

Search for a τ^{+}τ^{-} Resonance in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} Events with the Belle II Experiment

We report the first search for a nonstandard-model resonance decaying into τ pairs in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} events in the 3.6-10  GeV/c^{2} mass range. We use a 62.8  fb^{-1} sample of e^{+}e^{-} collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axionlike particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ pairs, ranging from 0.7 to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5  GeV/c^{2} and for the axionlike particle model over the entire mass range.

Measurement of CP Violation in B^{0}→K_{S}^{0}π^{0} Decays at Belle II

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6}  BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

Test of Light-Lepton Universality in the Rates of Inclusive Semileptonic B-Meson Decays at Belle II

We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189  fb^{-1} from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3  GeV/c to obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.

First Measurement of the Michel Parameter ξ^{'} in the τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} Decay at Belle

We report the first measurement of the Michel parameter ξ^{'} in the τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decay with a new method proposed just recently. The measurement is based on the reconstruction of the τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} events with subsequent muon decay in flight in the Belle central drift chamber. The analyzed data sample of 988  fb^{-1} collected by the Belle detector corresponds to approximately 912×10^{6} τ^{+}τ^{-} pairs. We measure ξ^{'}=0.22±0.94(stat)±0.42(syst), which is in agreement with the standard model prediction of ξ^{'}=1. Statistical uncertainty dominates in this study, being a limiting factor, while systematic uncertainty is well under control. Our analysis proved the practicability of this promising method and its prospects for further precise measurement in future experiments.

First Observation of Λπ^{+} and Λπ^{-} Signals near the K[over ¯]N(I=1) Mass Threshold in Λ_{c}^{+}→Λπ^{+}π^{+}π^{-} Decay

Using the data sample of 980  fb^{-1} collected with the Belle detector operating at the KEKB asymmetric-energy e^{+}e^{-} collider, we present the results of an investigation of the Λπ^{+} and Λπ^{-} invariant mass distributions looking for substructure in the decay Λ_{c}^{+}→Λπ^{+}π^{+}π^{-}. We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Λπ^{+} (Λπ^{-}) combination a mass of 1434.3±0.6(stat)±0.9(syst)  MeV/c^{2} [1438.5±0.9(stat)±2.5(syst)  MeV/c^{2}], an intrinsic width of 11.5±2.8(stat)±5.3(syst)  MeV/c^{2} [33.0±7.5(stat)±23.6(syst)  MeV/c^{2}] with a significance of 7.5σ (6.2σ). As these two signals are very close to the K[over ¯]N threshold, we also investigate the possibility of a K[over ¯]N cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.

Characterization of novel antibodies that recognize sialylated keratan sulfate and lacto-N-fucopentaose I on human induced pluripotent cells: comparison with existing antibodies

This report describes the isolation and characterization of two new antibodies, R-6C (IgM) and R-13E (IgM), which were generated in C57BL/6 mice (Mus musculus) using the Tic (JCRB1331) human induced pluripotent cell (hiPSC) line as an antigen, and their comparisons with two existing antibodies, R-10G (IgG1) and R-17F (IgG1). Their epitopes were studied by western blotting after various glycosidase digestions, binding analyses using enzyme-linked immunosorbent assays (ELISAs) and microarrays with various synthetic oligosaccharides. The minimum epitope structures identified were: Siaα2-3Galβ1-3GlcNAc(6S)β1-3Galβ1-4GlcNAc(6S)β1 (R-6C), Fucα1-2Galβ1-3GlcNAcβ1-3Galβ1 (R-13E), Galβ1-4GlcNAc(6S)β1-3Galβ1-4GlcNAc(6S)β1 (R-10G), and Fucα1-2Galβ1-3GlcNAβ1-3Galβ1-4Glc (lacto-N-fucopentaose I) (R-17F). Most glycoprotein epitopes are expressed as O-glycans. The common feature of these epitopes is the presence of an N-acetyllactosamine type 1 structure (Galβ1-3GlcNAc) at their nonreducing termini, followed by a type 2 structure (Galβ1-4GlcNAc); this arrangement comprises a type 1-type 2 motif. This motif is also shared by TRA-1-60, a traditional onco-fetal antigen. In contrast, the R-10G epitope has a type 2-type 2 motif. Among these antibodies, R-17F and R-13E exhibit cytotoxic activity toward hiPSCs. R-17F and R-13E exhibit extremely high similarity in the amino acid sequences in their complementarity-determining regions (CDRs), which is consistent with their highly similar glycan recognition. These antibodies are excellent tools for investigating the biological functions of glycoconjugates in hiPSCs/hESCs; they could be useful for the selection, isolation and selective killing of such undifferentiated pluripotent stem cells.

Search for a Dark Photon and an Invisible Dark Higgs Boson in μ^{+}μ^{-} and Missing Energy Final States with the Belle II Experiment

The dark photon A^{'} and the dark Higgs boson h^{'} are hypothetical particles predicted in many dark sector models. We search for the simultaneous production of A^{'} and h^{'} in the dark Higgsstrahlung process e^{+}e^{-}→A^{'}h^{'} with A^{'}→μ^{+}μ^{-} and h^{'} invisible in electron-positron collisions at a center-of-mass energy of 10.58 GeV in data collected by the Belle II experiment in 2019. With an integrated luminosity of 8.34  fb^{-1}, we observe no evidence for signal. We obtain exclusion limits at 90% Bayesian credibility in the range of 1.7-5.0 fb on the cross section and in the range of 1.7×10^{-8}-200×10^{-8} on the effective coupling ϵ^{2}×α_{D} for the A^{'} mass in the range of 4.0  GeV/c^{2}<M_{A^{'}}<9.7  GeV/c^{2} and for the h^{'} mass M_{h^{'}}<M_{A^{'}}, where ϵ is the mixing strength between the standard model and the dark photon and α_{D} is the coupling of the dark photon to the dark Higgs boson. Our limits are the first in this mass range.

Evidence of a New Excited Charmed Baryon Decaying to Σ_{c}(2455)^{0,++}π^{±}

We present the study of B[over ¯]^{0}→Σ_{c}(2455)^{0,++}π^{±}p[over ¯] decays based on 772×10^{6}  BB[over ¯] events collected with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The Σ_{c}(2455)^{0,++} candidates are reconstructed via their decay to Λ_{c}^{+}π^{∓} and Λ_{c}^{+} decays to pK^{-}π^{+}, pK_{S}^{0}, and Λπ^{+} final states. The corresponding branching fractions are measured to be B(B[over ¯]^{0}→Σ_{c}(2455)^{0}π^{+}p[over ¯])=(1.09±0.06±0.07)×10^{-4} and B(B[over ¯]^{0}→Σ_{c}(2455)^{++}π^{-}p[over ¯])=(1.84±0.11±0.12)×10^{-4}, which are consistent with the world average values with improved precision. A new structure is found in the M_{Σ_{c}(2455)^{0,++}π^{±}} spectrum with a significance of 4.2σ including systematic uncertainty. The structure is possibly an excited Λ_{c}^{+} and is tentatively named Λ_{c}(2910)^{+}. Its mass and width are measured to be (2913.8±5.6±3.8)  MeV/c^{2} and (51.8±20.0±18.8)  MeV, respectively. The products of branching fractions for the Λ_{c}(2910)^{+} are measured to be B(B[over ¯]^{0}→Λ_{c}(2910)^{+}p[over ¯])×B(Λ_{c}(2910)^{+}→Σ_{c}(2455)^{0}π^{+})=(9.5±3.6±1.6)×10^{-6} and B(B[over ¯]^{0}→Λ_{c}(2910)^{+}p[over ¯])×B(Λ_{c}(2910)^{+}→Σ_{c}(2455)^{++}π^{-})=(1.24±0.35±0.10)×10^{-5}. Here, the first and second uncertainties are statistical and systematic, respectively.

Establishment of the removal method of undifferentiated induced pluripotent stem cells coexisting with chondrocytes using R-17F antibody

Aim: Tumorigenicity of residual undifferentiated induced pluripotent stem cells (iPSCs) is a major concern. The purpose of this study was to investigate the optimal conditions for removal of iPSCs using R-17F antibody, which recognizes specific glycosphingolipids glycans on undifferentiated iPSCs and exhibits selective cytotoxicity to iPSCs. Materials & methods: After adding of R-17F and secondary antibody to co-cultured iPSCs and chondrocytes, residual iPSCs were quantitatively evaluated by iPS specific glycome analysis. Results: Undifferentiated iPSCs were sufficiently removed using R-17F in combination with an equal amount of a secondary antibody. Furthermore, teratomas were not observed upon transplantation of co-cultured cells pretreated under the same conditions into testes of immunodeficient mice. Conclusion: This removal method incorporating R-17F may be useful for regenerative medicine using iPSCs.

Folie à Deux During Self-Quarantine in the COVID-19 Pandemic: a Case Report

Folie à deux is also known as psychosis of association or shared paranoid disorder. We describe a mother and her two daughters who experienced shared delusions and hallucinations during self-quarantine in COVID-19 pandemic. The mother was later diagnosed with schizophrenia and prescribed brexpiprazole, whereas her two daughters were diagnosed with psychosis of association affected by their mother.

Search for a Light Higgs Boson in Single-Photon Decays of ϒ(1S) Using ϒ(2S)→π^{+}π^{-}ϒ(1S) Tagging Method

We search for a light Higgs boson (A^{0}) decaying into a τ^{+}τ^{-} or μ^{+}μ^{-} pair in the radiative decays of ϒ(1S). The production of ϒ(1S) mesons is tagged by ϒ(2S)→π^{+}π^{-}ϒ(1S) transitions, using 158×10^{6} ϒ(2S) events accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant A^{0} signals in the mass range from the τ^{+}τ^{-} or μ^{+}μ^{-} threshold to 9.2  GeV/c^{2} are observed. We set the upper limits at 90% credibility level (C.L.) on the product branching fractions for ϒ(1S)→γA^{0} and A^{0}→τ^{+}τ^{-} varying from 3.8×10^{-6} to 1.5×10^{-4}. Our results represent an approximately twofold improvement on the current world best upper limits for the ϒ(1S)→γA^{0}(→τ^{+}τ^{-}) production. For A^{0}→μ^{+}μ^{-}, the upper limits on the product branching fractions for ϒ(1S)→γA^{0} and A^{0}→μ^{+}μ^{-} are at the same level as the world average limits, and vary from 3.1×10^{-7} to 1.6×10^{-5}. The upper limits at 90% credibility level on the Yukawa coupling f_{ϒ(1S)} and mixing angle sinθ_{A^{0}} are also given.

Precise Measurement of the D^{0} and D^{+} Lifetimes at Belle II

We report a measurement of the D^{0} and D^{+} lifetimes using D^{0}→K^{-}π^{+} and D^{+}→K^{-}π^{+}π^{+} decays reconstructed in e^{+}e^{-}→cc[over ¯] data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The data, collected at center-of-mass energies at or near the ϒ(4S) resonance, correspond to an integrated luminosity of 72  fb^{-1}. The results, τ(D^{0})=410.5±1.1(stat)±0.8(syst)  fs and τ(D^{+})=1030.4±4.7(stat)±3.1(syst)  fs, are the most precise to date and are consistent with previous determinations.

Search for B^{+}→K^{+}νν[over ¯] Decays Using an Inclusive Tagging Method at Belle II

A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63  fb^{-1} collected at the ϒ(4S) resonance and a sample of 9  fb^{-1} collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B^{+}→K^{+}νν[over ¯] decay, but also the inclusive properties of the other B meson in the ϒ(4S)→BB[over ¯] event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B^{+}→K^{+}νν[over ¯] of 4.1×10^{-5} is set at the 90% confidence level.

Trans-stenotic pressure gradient as derived from CT improves patient management: ADVANCE registry

Background

The change in fractional flow reserve derived from CT (FFRCT) value across a coronary stenosis (ΔFFRCT) improves the physiological characterization of coronary artery disease (CAD). The role of ΔFFRCT in guiding risk-stratification and downstream testing in patients with stable CAD is unknown.

Purpose

To investigate the incremental value of ΔFFRCT at predicting early revascularization and improving efficacy of resource utilization.

Methods

Patients with CAD on CT coronary angiography (CTCA) were enrolled in an international multicenter registry. Patients with non-evaluable FFRCT analysis were excluded. The CTCA was assessed for: stenosis severity as per CAD-Reporting and Data System (CAD-RADS), lesion length and lesion-specific FFRCT measured 2 cm distal to stenosis. Risk factors and actual treatment (revascularization vs medical therapy) at 90-day follow-up were recorded. Multivariable logistic regression analysis for early revascularization was conducted. The incremental discrimination for revascularization prediction was compared among 3 models (model 1: risk factors + lesion length and location + CAD-RADS; model 2: model 1 + lesion-specific FFRCT; model 3: model 2 + ΔFFRCT). Simulating ICA referral for patients with CAD-RADS ≥3 and lesion-specific FFRCT ≤0.8, the potential impact of ΔFFRCT at reducing ICA referral and improving the ratio of subsequent revascularization was assessed.

Results

Of 4730 patients (66±10 years; 34% female), 2092 (42.7%) underwent ICA and 1168 (24.7%) underwent early revascularization. With increasing ΔFFRCT, a higher incidence of revascularization (Figure 1A) and an increase in the revascularization to ICA ratio was observed (Figure 1B). ΔFFRCT &gt;0.13 was the optimal cut-off for predicting revascularization as determined by the Youden index. ΔFFRCT remained an independent predictor for early revascularization (odds ratio per 0.05 increase with 95% CI, 1.31 [1.26–1.35]; p&lt;0.0001) after adjusting for risk factors, CAD-RADS, lesion length and location, and FFRCT. Among the 3 models, model 3, which included ΔFFRCT showed the highest AUC and improved discrimination power compared to model 2 (0.87 [0.86–0.88] vs 0.85 [0.84–0.86]; p&lt;0.0001] (Figure 2), with the greatest incremental value for ΔFFRCT observed in patients with lesion-specific FFRCT between 0.71–0.80. In patients with CAD-RADS ≥3 and lesion-specific FFRCT ≤0.8, a diagnostic strategy incorporating ΔFFRCT &gt;0.13 would potentially reduce ICA referral by 32.2% (1638 to 1110) and improve the revascularization to ICA ratio from 65.2% [1068/1638] to 73.1% [811/1110].

Conclusions

The characterization of CAD with ΔFFRCT improves the identification of patients requiring early revascularization as compared to a standard diagnostic strategy of CTCA with FFRCT, particularly for those with lesion-specific FFRCT of 0.71–0.80. ΔFFRCT has the potential to aid decision making for ICA referral and improve the efficiency of resource utilization.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): HeartFlow, Inc., Redwood City, CA, USA ΔFFRCT and actual treatmentROC curve for early revascularization

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

POS0975 CLINICAL CHARACTERISTICS OF NONRADIOGRAPHIC AXIAL SPONDYLOARTHRITIS IN ASIAN COUNTRIES COMPARED TO OTHER REGIONS: RESULTS OF THE INTERNATIONAL CROSS-SECTIONAL ASAS-COMOSPA STUDY

Background:

Clinical characteristics of nonradiographic axial spondyloarthritis (nr-ax-SpA) are highly variable across patients, and may potentially vary across patient populations, particularly due to differing distributions of human leukocyte antigens (HLA) and other genetic factors. The majority of nr-ax-SpA studies have been conducted in Europe, the United States, and small studies are reported from Asia [1].

Objectives:

To delineate clinical characteristics of patients with nr-ax-SpA in Asian countries in comparison to other areas of the world.

Methods:

Utilizing the ASAS-COMOSPA data, an international cross-sectional observational study of SpA patients, we analyzed information on demographics, disease characteristics, comorbidities, and risk factors. Patients were classified by region: Asia (China, Japan, Singapore, South Korea, and Taiwan), and non-Asian countries (Europe, Americas, and Africa); patient characteristics, including diagnosis and treatment, were compared.

Results:

Among 3984 SpA patients included in the study, 1094 were from centers in Asian countries, and 2890 from other regions. 112/780 (14.4%) of axial SpA patients in Asian countries were nr-ax-SpA, substantially less than in other countries (486/1997, 24.3%). Nr-ax-SpA patients in Asian countries compared to nr-ax-SpA in other countries were more likely male (75.9 vs 47.1%), have onset (22.8 vs 27.8 years) and diagnosis (27.2 vs 34.5 years) at younger age, and experience less diagnostic delay (1.88 vs 2.92 years) (Table 1). Nr-ax-SpA patients in Asian countries have higher prevalence of positive HLA-B27 (90.6% vs 61.9%) and fewer peripheral signs such as arthritis, enthesitis, or dactylitis (53.6% vs 66.3%) but have similar rate of extra-articular manifestations (psoriasis, IBD, or uveitis) and co-morbidities. Disease activity, functional impairment, and inflammation on MRI were less in nr-ax-SpA patients in Asian countries. NSAIDs response was higher and use of methotrexate and b-DMARDs were lower among nr-ax-SpA in Asian countries.

Conclusion:

Among axial SpA patients, substantially lower frequency of nr-ax-SpA was observed in Asian countries compared to other regions of the world. Nr-ax-SpA patients in Asian countries were predominantly male, and had younger disease onset with higher HLA-B27 positivity rate and less peripheral signs, and better response to NSAIDs. These results offer an opportunity to improve both early diagnosis and treatment of nr-ax-SpA patients in Asian countries.

Table 1.

Characteristics of nonradiographic axial SpA in Asia versus non-Asian regions

VariablesAsianon-Asian regionsp valueN112486Age at disease diagnosis, yrs27.2 [21.1, 39.6]34.5 [27.7, 41.7]<0.001Diagnostic delay, yrs1.88 [0.27, 5.56]2.92 [0.59, 9.58]0.011Male (%)85 (75.9)229 (47.1)<0.001Sacroiliitis on MRI among tested (%)49 (67.1)341 (82.2)0.005HLA B27 positivity among measured (%)96 (90.6)273 (61.9)<0.001Inflammatory Back Pain (%)107 (95.5)478 (98.4)0.076Arthritis, enthesitis, or dactylitis (%)60 (53.6)322 (66.3)0.016Psoriasis (%)12 (10.7)82 (16.9)0.142Uveitis (%)20 (17.9)81 (16.7)0.870Inflammatory bowel disease (%)5 (4.5)27 (5.6)0.817Elevated CRP (%)37 (33.0)213 (43.8)0.048Physician global assessment (0-10)2.0 [1.0, 5.0]2.0 [1.0, 4.0]0.741Patient global assessment (0-10)3.0 [1.0, 6.0]4.0 [2.0, 6.0]0.012ASDAS-CRP1.40 [0.95, 2.08]1.97 [1.21, 2.78]<0.001BASFI0.8 [0.05, 2.65]2.9 [0.8, 5.6]<0.001Good response to NSAIDs (%)80 (71.4)272 (56.0)0.004Methotrexate use (%)18 (16.1)134 (27.6)0.016Biological DMARDs use (%)27 (24.1)191 (39.3)0.004

References:

[1]López-Medina C, Ramiro S, van der Heijde D, et al. Characteristics and burden of disease in patients with radiographic and non-radiographic axial Spondyloarthritis: a comparison by systematic literature review and meta-analysis. RMD Open. 2019 Nov 21;5(2): e001108.

Acknowledgements:

This study was conducted under the umbrella of the International Society for Spondyloarthritis Assessment (ASAS) and COMOSPA study was supported by unrestricted grants from Pfizer, AbbVie and UCB.

Disclosure of Interests:

Keisuke Ono: None declared, Mitsumasa Kishimoto Speakers bureau: AbbVie, Amgen-Astellas BioPharma, Asahi-Kasei Pharma, Astellas, Ayumi Pharma, BMS, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Gilead, Janssen, Kyowa Kirin, Novartis, Ono Pharma, Pfizer, Tanabe-Mitsubishi, Teijin Pharma, and UCB Pharma, Consultant of: AbbVie, Amgen-Astellas BioPharma, Asahi-Kasei Pharma, Astellas, Ayumi Pharma, BMS, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Gilead, Janssen, Kyowa Kirin, Novartis, Ono Pharma, Pfizer, Tanabe-Mitsubishi, Teijin Pharma, and UCB Pharma, Sho Fukui: None declared, Satoshi Kawaai: None declared, Gautam A. Deshpande: None declared, Kazuki Yoshida Consultant of: OM1, Inc., Grant/research support from: Corrona, LLC, Naomi Ichikawa: None declared, Yuko Kaneko Speakers bureau: AbbVie, Astellas, Ayumi, Bristol-Myers Squibb, Chugai, Eisai, Eli Lilly, Hisamitsu, Jansen, Kissei, Pfizer, Sanofi, Takeda, Tanabe-Mitsubishi, and UCB, Taku Kawasaki: None declared, Kazuo Matsui: None declared, Mitsuhiro Morita: None declared, Kurisu Tada: None declared, Naoho Takizawa: None declared, Naoto Tamura: None declared, Atsuo Taniguchi: None declared, Yoshinori Taniguchi: None declared, Shigeyoshi Tsuji: None declared, Shigeto Kobayashi: None declared, Masato Okada: None declared, Clementina López-Medina: None declared, Anna Moltó Consultant of: AbbVie, Pfizer, MSD, Novartis, Gilead, Lilly and UCB, Grant/research support from: AbbVie, Pfizer, MSD, Novartis, Gilead, Lilly and UCB, Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, Bayer, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead, Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma, Employee of: Imaging Rheumatology bv. (Director), Maxime Dougados: None declared, Yoshinori Komagata: None declared, Tetsuya Tomita: None declared, Shinya Kaname: None declared.

Evidence for X(3872)→J/ψπ^{+}π^{-} Produced in Single-Tag Two-Photon Interactions

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the positron in the final state, exploring the highly virtual photon region. The search is performed in e^{+}e^{-}→e^{+}e^{-}J/ψπ^{+}π^{-}, using 825  fb^{-1} of data collected by the Belle detector operated at the KEKB e^{+}e^{-} collider. We observe three X(3872) candidates, where the expected background is 0.11±0.10 events, with a significance of 3.2σ. We obtain an estimated value for Γ[over ˜]_{γγ}B(X(3872)→J/ψπ^{+}π^{-}) assuming the Q^{2} dependence predicted by a cc[over ¯] meson model, where -Q^{2} is the invariant mass squared of the virtual photon. No X(3915)→J/ψπ^{+}π^{-} candidates are found.

Japanese multicenter registry evaluating the antegrade dissection reentry with cardiac computed tomography for chronic coronary total occlusion

Objective

This study was performed to evaluate the efficacy of cardiac computed tomography (CT) for antegrade dissection re-entry (ADR) technique in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

Background

Although PCI of CTO is a rapidly evolving field, procedure success rate remains suboptimal. Recently, ADR with Stingray device for CTO-PCI has also evolved to one of the pillar technique of the hybrid algorithm. Although the success rate of the device could be improved, it also remains not always high especially as first crossing strategy.

Methods

Forty eight patients with total occlusion suitable for revascularization evaluated by baseline coronary angiography and cardiac CT were enrolled in this study from April 2017 to April 2019 from 30 enrolled centers. The primary observation was procedural success. Furthermore, all puncture point with Stingray were analyzed by cardiac CT. In each point, 1) plaques on the isolated myocardial side at distal puncture site (+1 point), 2) any plaques excluded above definition at distal puncture site (+2 points), 3) calcification on both 1 and 2 at distal puncture site (+1 point) were analyzed and calculated the score (Score 0–3) (Figure 1).

Results

Overall procedure success rate was 95.8% (46/48) and antegrade success rate was 91.3% (42/46). Sixteen cases were succeeded with single guidewire escalation and 32 cases were attempted ADR with Stingray system. Within them, 25 cases were succeeded and 7 cases were observed puncture failure. And 3cases were succeeded with IVUS guide and 2 cases were with retrograde appTechnical success rate with stingray was 78.1% (25/32). Cardiac CT was analyzed 60 puncture sites in 32 cases which were attempted ADR with stingray system (1.88 sites/case). CT score at ADR success point was significantly smaller compare to that at ADR failure point (0.68±1.09 vs 1.77±1.09, p&lt;0.0001).

Conclusions

Pre procedure Cardiac CT and CT score might be useful for ADR technique in CTO PCI not only for case selection but also for puncture site selection.

Figure 1

Funding Acknowledgement

Type of funding source: None

Potent Inhibition of Biphasic Tubular Reabsorption of Lithium by Acetazolamide and Foscarnet in Rats

Lithium is mainly excreted into urine, and a large fraction of lithium filtered through glomeruli is reabsorbed in the proximal tubule. However, the mechanisms responsible for lithium reabsorption remain unclear. We previously reported that the reabsorption of lithium was biphasic in rats, and that foscarnet inhibited lithium reabsorption with a high affinity type. We herein evaluated the effects of acetazolamide and foscarnet on the renal excretion of lithium in rats treated with lithium chloride at 2 doses. In rats intravenously injected with a bolus of 25 mg/kg lithium chloride, acetazolamide facilitated the urinary excretion of lithium, and increased the fractional excretion of lithium from 0.446 to 0.953, near the theoretically maximum value. At a dose of 2.5 mg/kg lithium chloride, the fractional excretion of lithium was 0.241 in control rats, 0.420 in rats administered acetazolamide, and 0.976 in rats administered acetazolamide and foscarnet. These results showed the potent inhibition of lithium reabsorption by acetazolamide and foscarnet in rats. And, it was exhibited that the effects of acetazolamide on lithium reabsorption differed with the dosages of lithium administered.

Measurement of R(D) and R(D^{*}) with a Semileptonic Tagging Method

The experimental results on the ratios of branching fractions R(D)=B(B[over ¯]→Dτ^{-}ν[over ¯]_{τ})/B(B[over ¯]→Dℓ^{-}ν[over ¯]_{ℓ}) and R(D^{*})=B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}), where ℓ denotes an electron or a muon, show a long-standing discrepancy with the standard model predictions, and might hint at a violation of lepton flavor universality. We report a new simultaneous measurement of R(D) and R(D^{*}), based on a data sample containing 772×10^{6}  BB[over ¯] events recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. In this analysis the tag-side B meson is reconstructed in a semileptonic decay mode and the signal-side τ is reconstructed in a purely leptonic decay. The measured values are R(D)=0.307±0.037±0.016 and R(D^{*})=0.283±0.018±0.014, where the first uncertainties are statistical and the second are systematic. These results are in agreement with the standard model predictions within 0.2, 1.1, and 0.8 standard deviations for R(D), R(D^{*}), and their combination, respectively. This work constitutes the most precise measurements of R(D) and R(D^{*}) performed to date as well as the first result for R(D) based on a semileptonic tagging method.

Search for an Invisibly Decaying Z^{'} Boson at Belle II in e^{+}e^{-}→μ^{+}μ^{-}(e^{±}μ^{∓}) Plus Missing Energy Final States

Theories beyond the standard model often predict the existence of an additional neutral boson, the Z^{'}. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z^{'} in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'} and of a lepton-flavor-violating Z^{'} in e^{+}e^{-}→e^{±}μ^{∓}Z^{'}. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an L_{μ}-L_{τ} theory, into upper limits on the Z^{'} coupling constant at the level of 5×10^{-2}-1 for M_{Z^{'}}≤6  GeV/c^{2}.

Stacking Fault Energy Analyses of Additively Manufactured Stainless Steel 316L and CrCoNi Medium Entropy Alloy Using In Situ Neutron Diffraction

Stacking fault energies (SFE) were determined in additively manufactured (AM) stainless steel (SS 316 L) and equiatomic CrCoNi medium-entropy alloys. AM specimens were fabricated via directed energy deposition and tensile loaded at room temperature. In situ neutron diffraction was performed to obtain a number of faulting-embedded diffraction peaks simultaneously from a set of (hkl) grains during deformation. The peak profiles diffracted from imperfect crystal structures were analyzed to correlate stacking fault probabilities and mean-square lattice strains to the SFE. The result shows that averaged SFEs are 32.8 mJ/m2 for the AM SS 316 L and 15.1 mJ/m2 for the AM CrCoNi alloys. Meanwhile, during deformation, the SFE varies from 46 to 21 mJ/m2 (AM SS 316 L) and 24 to 11 mJ/m2 (AM CrCoNi) from initial to stabilized stages, respectively. The transient SFEs are attributed to the deformation activity changes from dislocation slip to twinning as straining. The twinning deformation substructure and atomic stacking faults were confirmed by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The significant variance of the SFE suggests the critical twinning stress as 830 ± 25 MPa for the AM SS 316 L and 790 ± 40 MPa for AM CrCoNi, respectively.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

Effect of acetazolamide on lithium reabsorption and lithium-induced GSK3β phosphorylation in rat kidney

Lithium promotes the phosphorylation of glycogen synthase kinase-3β (GSK3β), and this reaction protects against acute kidney injury mediated by renal apoptosis. Lithium is considered to be reabsorbed by sodium-phosphate cotransporters and sodium-proton exchanger NHE3. This study evaluated the relation between the lithium reabsorption and the phosphorylation of GSK3β, by using acetazolamide, an NHE3 inhibitor. In rats infused with lithium chloride, the plasma concentration of lithium was 4.77 mEq/l, and the renal clearance of lithium and its fractional excretion were calculated to be 2.29 ml/min/kg and 0.405, respectively. Coadministration of acetazolamide decreased creatinine clearance and the reabsorption rate of lithium, increased the fractional excretion of lithium, and did not affect its plasma concentration. Western blot analysis exhibited the facilitation of GSK3β phosphorylation in the kidney cortex by lithium infusion, and acetazolamide inhibited the lithium-induced phosphorylation of GSK3β. Lithium did not affect GSK3β phosphorylation in the liver and did not affect Akt in the kidney cortex and liver. These data show that lithium reabsorption contributes to GSK3β phosphorylation in the kidney cortex.

Glycan Markers of Human Stem Cells Assigned with Beam Search Arrays

Glycan antigens recognized by monoclonal antibodies have served as stem cell markers. To understand regulation of their biosynthesis and their roles in stem cell behavior precise assignments are required. We have applied state-of-the-art glycan array technologies to compare the glycans bound by five antibodies that recognize carbohydrates on human stem cells. These are: FC10.2, TRA-1-60, TRA-1-81, anti-i and R-10G. Microarray analyses with a panel of sequence-defined glycans corroborate that FC10.2, TRA-1-60, TRA-1-81 recognize the type 1-(Galβ-3GlcNAc)-terminating backbone sequence, Galβ-3GlcNAcβ-3Galβ-4GlcNAcβ-3Galβ-4GlcNAc, and anti-i, the type 2-(Galβ-4GlcNAc) analog, Galβ-4GlcNAcβ-3Galβ-4GlcNAcβ-3Galβ-4GlcNAc, and we determine substituents they can accommodate. They differ from R-10G, which requires sulfate. By Beam Search approach, starting with an antigen-positive keratan sulfate polysaccharide, followed by targeted iterative microarray analyses of glycan populations released with keratanases and mass spectrometric monitoring, R-10G is assigned as a mono-sulfated type 2 chain with 6-sulfation at the penultimate N-acetylglucosamine, Galβ-4GlcNAc(6S)β-3Galβ-4GlcNAcβ-3Galβ-4GlcNAc. Microarray analyses using newly synthesized glycans corroborate the assignment of this unique determinant raising questions regarding involvement as a ligand in the stem cell niche.

P14.01 Differential diagnosis of IDH mutant/IDH wildtype of glioma by using 11C-methionine, 11C-choline, and18F-fluorodeoxyglucose positron emission tomography

BACKGROUND

Positron emission tomography (PET) is important in noninvasive diagnostic imaging of gliomas. There are many PET studies on glioma diagnosis based on the 2007 World Health Organization (WHO) classification; however, there are no studies on glioma diagnosis using the new classification (the 2016 WHO classification).Here we investigated the relationship between PET imaging using 11C-methionine (MET), 11C-choline (CHO), and 18F-fluorodeoxyglucose (FDG) and wildtype isocitrate dehydrogenase (IDH) (IDH-wt)/mutant IDH (IDH-mut) in astrocytic and oligodendroglial tumors according to the 2016 WHO classification.

MATERIAL AND METHODS

In total, 105 patients with newly diagnosed cerebral gliomas (six diffuse astrocytomas [DAs] with IDH-wt, six DAs with IDH-mut, seven anaplastic astrocytomas [AAs] with IDH-wt, 24 AAs with IDH-mut, 26 glioblastomas [GBMs] with IDH-wt, five GBMs with IDH-mut, 19 oligodendrogliomas [ODs], and 12 anaplastic oligodendrogliomas [AOs]) were included. All OD and AO patients had both IDH-mut and 1p/19q codeletion. The maximum standardized uptake values (SUVs) of the tumor/normal cortex mean SUV ratios (T/N ratios) for MET, CHO, and FDG were calculated; the mean T/N ratios of DA, AA, and GBM with IDH-wt/IDH-mut were compared. The diagnostic accuracy for distinguishing gliomas with IDH-wt from those with IDH-mut was assessed using receiver operating characteristic (ROC) curve analysis of the mean T/N ratios for the three PET tracers.

RESULTS

There were significant differences in the mean T/N ratios for all three PET tracers between the IDH-wt and IDH-mut groups including all histological classifications (p<0.001). Among the 27 gliomas with mean T/N ratios higher than the cutoff values for all three PET tracers, 23 (85.2%) were classified into the IDH-wt group using ROC analysis. In DA, there were no significant differences in the T/N ratios for MET, CHO, and FDG between the IDH-wt and IDH-mut groups. In AA, the mean T/N ratios of all three PET tracers in the IDH-wt group were significantly higher than those in the IDH-mut group (p<0.001). In GBM, the mean T/N ratio in the IDH-wt group was significantly higher than that of the IDH-mut group for both MET (p=0.034) and CHO (p=0.01). However, there was no significant difference in the ratio for FDG.

CONCLUSIONS

PET imaging using MET, CHO, and FDG was confirmed to be informative for preoperatively differentiating gliomas according to the 2016 WHO classification, particularly for differentiating IDH-wt and IDH-mut tumors.

First Measurements of Absolute Branching Fractions of the Ξ_{c}^{0} Baryon at Belle

We present the first measurements of absolute branching fractions of Ξ_{c}^{0} decays into Ξ^{-}π^{+}, ΛK^{-}π^{+}, and pK^{-}K^{-}π^{+} final states. The measurements are made using a dataset comprising (772±11)×10^{6} BB[over ¯] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. We first measure the absolute branching fraction for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} using a missing-mass technique; the result is B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})=(9.51±2.10±0.88)×10^{-4}. We subsequently measure the product branching fractions B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→Ξ^{-}π^{+}), B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→ΛK^{-}π^{+}), and B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+}) with improved precision. Dividing these product branching fractions by the result for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} yields the following branching fractions: B(Ξ_{c}^{0}→Ξ^{-}π^{+})=(1.80±0.50±0.14)%, B(Ξ_{c}^{0}→ΛK^{-}π^{+})=(1.17±0.37±0.09)%, and B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+})=(0.58±0.23±0.05)%. For the above branching fractions, the first uncertainties are statistical and the second are systematic. Our result for B(Ξ_{c}^{0}→Ξ^{-}π^{+}) can be combined with Ξ_{c}^{0} branching fractions measured relative to Ξ_{c}^{0}→Ξ^{-}π^{+} to yield other absolute Ξ_{c}^{0} branching fractions.

Observation of Transverse Λ/Λ[over ¯] Hyperon Polarization in e^{+}e^{-} Annihilation at Belle

We report the first observation of the spontaneous polarization of Λ and Λ[over ¯] hyperons transverse to the production plane in e^{+}e^{-} annihilation, which is attributed to the effect arising from a polarizing fragmentation function. For inclusive Λ/Λ[over ¯] production, we also report results with subtracted feed-down contributions from Σ^{0} and charm. This measurement uses a dataset of 800.4  fb^{-1} collected by the Belle experiment at or near a center-of-mass energy of 10.58 GeV. We observe a significant polarization that rises with the fractional energy carried by the Λ/Λ[over ¯] hyperon.

Search for a Light CP-odd Higgs Boson and Low-Mass Dark Matter at the Belle Experiment

We report on the first Belle search for a light CP-odd Higgs boson, A^{0}, that decays into low mass dark matter, χ, in final states with a single photon and missing energy. We search for events produced via the dipion transition ϒ(2S)→ϒ(1S)π^{+}π^{-}, followed by the on-shell process ϒ(1S)→γA^{0} with A^{0}→χχ, or by the off-shell process ϒ(1S)→γχχ. Utilizing a data sample of 157.3×10^{6} ϒ(2S) decays, we find no evidence for a signal. We set limits on the branching fractions of such processes in the mass ranges M_{A^{0}}<8.97  GeV/c^{2} and M_{χ}<4.44  GeV/c^{2}. We then use the limits on the off-shell process to set competitive limits on WIMP-nucleon scattering in the WIMP mass range below 5  GeV/c^{2}.

Observation of ϒ(2S)→γη_{b}(1S) Decay

We report the observation of ϒ(2S)→γη_{b}(1S) decay based on an analysis of the inclusive photon spectrum of 24.7  fb^{-1} of e^{+}e^{-} collisions at the ϒ(2S) center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We measure a branching fraction of B[ϒ(2S)→γη_{b}(1S)]=(6.1_{-0.7-0.6}^{+0.6+0.9})×10^{-4} and derive an η_{b}(1S) mass of 9394.8_{-3.1-2.7}^{+2.7+4.5}  MeV/c^{2}, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.

Observation of ϒ(4S)→η^{'}ϒ(1S)

We report the first observation of the hadronic transition ϒ(4S)→η^{'}ϒ(1S), using 496  fb^{-1} data collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We reconstruct the η^{'} meson through its decays to ρ^{0}γ and to π^{+}π^{-}η, with η→γγ. We measure B(ϒ(4S)→η^{'}ϒ(1S))=[3.43±0.88(stat)±0.21(syst)]×10^{-5}, with a significance of 5.7σ.

Search for B^{-}→μ^{-}ν[over ¯]_{μ} Decays at the Belle Experiment

We report the results of a search for the rare, purely leptonic decay B^{-}→μ^{-}ν[over ¯]_{μ} performed with a 711  fb^{-1} data sample that contains 772×10^{6}  BB[over ¯] pairs, collected near the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The signal events are selected based on the presence of a high momentum muon and the topology of the rest of the event showing properties of a generic B-meson decay, as well as the missing energy and momentum being consistent with the hypothesis of a neutrino from the signal decay. We find a 2.4 standard deviation excess above background including systematic uncertainties, which corresponds to a branching fraction of B(B^{-}→μ^{-}ν[over ¯]_{μ})=(6.46±2.22±1.60)×10^{-7} or a frequentist 90% confidence level interval on the B^{-}→μ^{-}ν[over ¯]_{μ} branching fraction of [2.9,10.7]×10^{-7}.

Isolation and Characterization of jararaca GPIb-BP, a Snake Venom Antagonist Specific to Platelet Glycoprotein lb

A platelet glycoprotein lb-binding protein (GPIb-BP) was isolated from the snake venom of Bothrops jararaca. Jararaca GPIb-BP showed a single band with Mr of 30,000, and two distinct bands with Mr. of 17,000/13,000 under non-reducing and reducing conditions, respectively, on SDS-polyacrylamide gel electrophoresis. Jararaca GPIb-BP itself induced neither platelet aggregation nor serotonin release from platelets, but specifically bound to GPIb (40,629 ± 2,521 molecules per normal platelet, with Kd 39.1 ± 2.4 nM at saturation). The purified venom protein completely inhibited ristocetin- or botrocetin-induccd von Willebrand factor (vWF) binding, and blocked the bovine vWF binding to GPIb, with IC50 values ranging from 28 to 42 nM, without affecting the platelet aggregation induced by ADP or α-thrombin. 1251-jararaca GPIb-BP binding to GPIb was not altered by the presence of human α-thrombin. Jararaca GPIb-BP at a final concentration of 104 nM totally abolished vWF-dependent shear- induced platelet aggregation (SIPA) at a high shear stress, but had no effect on SIPA at a low shear stress. Reduced and S-carboxyamidomethylated jararaca GPIb-BP lost its inhibitory activity on SIPA. The NH2-terminal amino acid sequences of the subunits revealed a high degree of homology with those of several Ca2+-dependent lectins, especially to those of two functionally opposite venom proteins, botrocetin (a vWF-modulator) and alboaggregin-B (a GPIb- modulator).