Two-Neutron Halo is Unveiled in ^{29}F

We report the measurement of reaction cross sections (σ_{R}^{ex}) of ^{27,29}F with a carbon target at RIKEN. The unexpectedly large σ_{R}^{ex} and derived matter radius identify ^{29}F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the 2p_{3/2} orbital, thereby vanishing the shell closure associated with the neutron number N=20. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius of ^{27}F but are challenged for ^{29}F.

FRI0129 DEVELOPMENT OF A PREDICTION MODEL FOR MAXIMUM METHOTREXATE (MTX) DOSE WITHOUT HEPATOTOXICITY USING AN INDEX OF ERYTHROCYTE MTX-POLYGLUTAMATE (MTXPG) LEVELS SPECULATED BY CLINICAL AND GENETIC MARKERS

Background:

MTX is transported into cells and retained long after polyglutamation. MTXPG level can predict response and possibly adverse effects of MTX. We reported erythrocyte MTXPG concentrations efficiently discriminated patients with and without hepatotoxicity1. We also developed genetic and clinical prediction models for efficacy and hepatotoxicity of MTX2. In the present study, we firstly investigated the effects of clinical and secondly genetic variables on the concentration of total MTXPG and determined oral maximum MTX dose without hepatotoxicity using these variables.

Objectives:

To develop a prediction model for maximum MTX dose without hepatotoxicity.

Methods:

Concentrations of erythrocyte MTX-PG (PG1 to PG4) were detected by LC-MS/MS and calculated total MTXPG as sum of them. MTX-PGn levels were measured in 265 RA patients including 40 patients with elevated AST or ALT (≥ 60 U/L; 1.5 times of upper limits) and the 6 SNPs of 6 gens related to MTXPG metabolism were identified by RT-PCR.

Results:

Total concentrations of MTXPG were 141.3 ± 86.5 and 87.6 ± 47.8 nmol/L (mean±SD) in 40 RA patients with hepatotoxicity and 225 patients without, respectively (p<0.0001). By ROC analysis, the two groups were most efficiently discriminated with cutoff concentration of 100.0 nmol/L (AUC 0.731). Next, genetic and clinical model to speculate the MTXPG concentration was established by multivariate analysis using 4 clinical and 3 genetic variables which were selected from 20 clinical and 6 genetic variables by univariate analysis (p<0.1). Finally, a speculation model for MTXPG concentration by 4 clinical variables (MTX dose, BMI, RBC count, and creatinine) and one genetic variable (GGH c.452C>T) was developed (Figure). When MTXPG concentration of 100 nmol/L was applied to the model, maximum MTX dose without hepatotoxicity was calculated for each patient asMTX dose (mg) = {100 (MTXPG) – 96 + 1.7*BMI + 28*RBC - 120*creatinine - 19.3*GGH(C/T)} / 7.7. Real dose of oral MTX exceeded the calculated dose in 23 of 40 patients (57.5%) with hepatotoxicity, whereas it exceeded in 95 of 223 patients (42.6%) without hepatotoxicity (OR 1.82, p=0.081).

Conclusion:

Maximum MTX dose without hepatotoxicity was speculated by several clinical and genetic markers without measurement of erythrocyte MTX-PG concentrations.

References:

[1]Takahashi M, et al: Clinical Pathology (Rinsho Byori), 67:433-442, 2019.

[2]Onishi A, et al: The Pharmacogenomics J, doi.org/10.1038/s41397-019-0134-9, 2019

Disclosure of Interests:

Shunichi Kumagai Grant/research support from: Astellas, Chugai, Mitsubishi Tanabe Co.Ltds, Consultant of: Sysmex Co.Ltd, Speakers bureau: many companies, Soshi Takahashi: None declared, Miho Takahashi: None declared, Toshiharu Saito: None declared, Katsuyuki Yoshida: None declared, Motoko Katayama: None declared, Saki Mukohara: None declared, Norihiko Amano: None declared, Akira Onishi Speakers bureau: AO received a speaker fee from Chugai, Ono Pharmaceutical, Eli Lilly, Mitsubishi-Tanabe, Asahi-Kasei, and Takeda, Masakazu Shinohara: None declared, Saori Hatachi: None declared

SAT0453 DELAYED DENOSUMAB INJECTIONS AND FRACTURES RISK AMONG SUBJECTS WITH OSTEOPOROSIS: A POPULATION-BASED COHORT STUDY

Background:

Denosumab is effective for osteoporosis, but discontinuation leads to rapid reversal of its therapeutic effect[1].

Objectives:

To estimate the risk for fracture among users of denosumab who delayed subsequent dosages compared with users who received dosages on time.

Methods:

Population-based cohort study. We included patients aged over 45 years who initiated denosumab for osteoporosis from UK THIN database, 2010 to 2019. Observational data were used to “emulate a hypothetical trial”[2, 3] with three dosing intervals: subsequent denosumab injection 24-28 weeks after prior dose (“on time”), delay by 4-16 weeks (“short delay”), and delay by over 16 weeks (“long delay”). The primary outcome was a composite of all fracture types. Secondary outcomes included major osteoporotic fracture, vertebral fracture, and hip fracture.

Results:

The rate of composite fracture per 1000 person-years was 58.9 for on-time, 61.7 for short delay, and 85.4 for long delay of subsequent denosumab injections. Compared to on-time injections, short delay had a hazard ratio (HR) for composite fracture 1.03 (95% CI 0.63-1.69) and long delay HR 1.44 (95% CI 0.96-2.17; p for trend 0.093). For major osteoporotic fractures, short delay had an HR 0.94 (95% CI 0.57-1.55) and long delay an HR of 1.69 (95% CI 1.01-2.83; p for trend 0.056). For vertebral fractures, short delay had an HR 1.48 (95% CI 0.58-3.79) and long delay 3.91 (95% CI 1.62-9.45; p for trend 0.005).

Conclusion:

While delayed subsequent denosumab dosages over 16 weeks was associated with an increased risk of vertebral and major osteoporotic fracture compared to no delay, composite fracture risk was not increased with longer delays.

References:

[1]Cummings SR, Ferrari S, Eastell R, et al. Vertebral Fractures After Discontinuation of Denosumab: A Post Hoc Analysis of the Randomized Placebo-Controlled FREEDOM Trial and Its Extension. J Bone Miner Res, 2017.

[2]Hernán MA. How to estimate the effect of treatment duration on survival outcomes using observational data. BMJ 2018.

[3]Hernán MA, Robins JM. Using Big Data to Emulate a Target Trial When a Randomized Trial Is Not Available. Am J Epidemiol 2016.

Table.

Rates and Adjusted Hazard Ratios of Fracture

On-timeShort delayLong delayP for linear trendComposite FractureRate (per 1000 person-years)5961.785.4-Unadjusted HR (95 %)Ref1.05 (0.62, 1.76)1.45 (0.95, 2.21)0.097Adjusted HR (95% CI)†Ref1.03 (0.63, 1.69)1.44 (0.96, 2.17)0.093Major Osteoporotic FractureRate (per 1000 person-years)34.831.958-Unadjusted HR (95 %)Ref0.92 (0.55, 1.53)1.67 (0.98, 2.84)0.074Adjusted HR (95% CI)†Ref0.94 (0.57, 1.55)1.69 (1.01, 2.83)0.056Vertebral FractureRate (per 1000 person-years)4.97.319.4-Unadjusted HR (95 %)Ref1.47 (0.58, 3.71)3.93 (1.59, 9.72)0.006Adjusted HR (95% CI)†Ref1.48 (0.58, 3.79)3.91 (1.62, 9.45)0.005Hip FractureRate (per 1000 person-years)10.29.618.3-Unadjusted HR (95 %)Ref0.94 (0.43, 2.04)1.78 (0.80, 3.97)0.18Adjusted HR (95% CI)†Ref0.97 (0.44, 2.12)1.75 (0.81, 3.79)0.173

†Adjusted model: adjusted by age, sex, baseline CCI index, major osteoporotic fracture, oral BP duration (years), 10-year risk of major osteoporotic fracture, prior denosumab doses.

Acknowledgments:

We acknowledge Dr. Dani Prieto-Alhambra for kindly providing Read codes.

Disclosure of Interests:

Houchen Lyu: None declared, Kazuki Yoshida: None declared, Sizheng Steven Zhao: None declared, Xabier García-Albéniz: None declared, Jie Wei: None declared, Chao Zeng: None declared, Sara Tedeschi: None declared, Benjamin Leder Grant/research support from: Research funding from Amgen, Guanghua Lei: None declared, Peifu Tang: None declared, Daniel Solomon Grant/research support from: Funding from Abbvie and Amgen unrelated to this work

SAT0172 UTILIZATION OF HYDROXYCHLOROQUINE AND CORTICOSTEROIDS AMONG LUPUS PATIENTS WITH INCIDENT END-STAGE RENAL DISEASE (ESRD) ONSET: A LONGITUDINAL STUDY USING USRDS REGISTRY

Background:

The development of ESRD due to lupus nephritis is one of the most common and serious complications of SLE. Mortality among SLE ESRD patients is 4-fold higher compared to lupus nephritis patients with preserved renal function1Mortality in SLE ESRD is also twice as high compared with non-SLE ESRD, even though SLE patients develop ESRD at a significantly younger age. In the absence of ESRD specific guidelines, medication utilization in SLE ESRD is unknown.

Objectives:

The objective of this study was to investigate the real-world current US-wide patterns of medication prescribing among lupus nephritis patients with new onset ESRD enrolled in the United States Renal Disease Systems (USRDS) registry. We specifically focused on HCQ and corticosteroids (CS) as the most used medications to treat SLE.

Methods:

Inclusion: USRDS patients 18 years and above with SLE as a primary cause of ESRD (International Classification of Diseases, 9thRevision (ICD9) diagnostic code 710.0, previously validated2). who developed ESRD between January 1st, 2006 and July 31, 2011 (to ensure at least 6 months of follow-up in the USRDS). Patients had to be enrolled in Medicare Part D (to capture pharmacy claims). The last follow-up date was defined as either the last date of continuous part D coverage or the end of the study period, Dec 31, 2013.

Results:

Of the 2579 patients included, 1708 (66%) were HCQ- at baseline, and 871 (34%) were HCQ+ at baseline. HCQ+ patients at baseline had a slightly lower duration of follow-up compared to HCQ- patients at baseline, median (IQR) of 2.32 (1.33, 3.97) years and 2.55 (1.44, 4.25) years, respectively, p= 0.02. During follow-up period, only 778 (30%) continued HCQ either intermittently or continuously to the last follow-up date, 1306 (51%) were never prescribed HCQ after baseline, and 495 (19%) discontinued HCQ before the last follow-up date. Of the 1801 patients who were either never prescribed or discontinued HCQ early after ESRD onset, 713 (40%) were prescribed CS to the end of the follow-up period: 55% were receiving a low dose <10mg/daily, and 43 were receiving moderate dose (10-20mg daily)

Conclusion:

HCQ may be underprescribed and CS may be overprescribed in SLE ESRD. Changing the current prescribing practices may improve outcomes in SLE ESRD

References:

[1]Yap DY et al., NDT 2012.

[2]Broder A et al., AC&R 2016.

Acknowledgments :

The data reported here have been supplied by the United States Renal Data System (USRDS). The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy or interpretation of the U.S. government.

Funding: :

NIH/NIAMS K23 AR068441 (A Broder), NIH/NIAMS R01 AR 057327 and K24 AR 066109 (KH Costenbader)

Disclosure of Interests: :

Anna R. Broder: None declared, Wenzhu Mowrey: None declared, Anna Valle: None declared, Beatrice Goilav: None declared, Kazuki Yoshida: None declared, Karen Costenbader Grant/research support from: Merck, Consultant of: Astra-Zeneca

FRI0519 IMPROVING RHEUMATOID ARTHRITIS COMPARATIVE EFFECTIVENESS RESEARCH USING THE TARGET TRIAL EMULATION FRAMEWORK: A SYSTEMATIC REVIEW

Background:

Methods used in observational comparative effectiveness research (CER) are highly variable. Target trial emulation is an intuitive design approach that encourages researchers to formulate their question as a hypothetical randomised controlled trial (RCT), or the “target trial”. Using observational data to emulate the target trial helps avoid common biases and has been shown to better align results with actual RCTs.

Objectives:

We systematically reviewed observational CER studies in rheumatoid arthritis to provide examples of design issues that might have been avoided by using target trial emulation.

Methods:

We searched for head-to-head effectiveness comparisons of biologic DMARDs in RA. Study designs were reviewed for components of target trial emulation: 1) eligibility criteria, 2) treatment strategies, 3) assignment procedures, 4) follow-up period, 5) outcome, 6) causal contrasts of interest (i.e., intention-to-treat or per-protocol effect), and 7) analysis plan. Reported methods were taken as the “emulation” of a corresponding target trial, to assess design issues that might introduce bias.

Results:

We found 31 CER studies, the majority of which had one design issue belonging to one of the 7 protocol components (Table 1). The most common issues were: 1) 17 out of 31 studies used post-baseline information to define baseline eligibility (e.g. requiring ≥1 follow-up), which can bias results; 2) 26 out of 31 studies did not declare their causal contrast of interest, which is often made difficult by issue 1 and impacts data analysis and interpretation; and 3) 9 out of 31 studies used statistical selection of confounders rather than pre-defining them, which can also introduce bias (e.g. through adjustment of collider or intermediate variables).

Table 1.

Design issues identified in 31 studies and reasons why they do not correspond to well-defined “target trials”

Design issues identified in study methodsHow these issues can be conceptualized in a RCT protocol1. Eligibility criteriaPost-baseline data requirement (17 out of 31 studies).Impossible to use future data at enrolment.Differential eligibility for each arm (5 studies).Breaks the notion of one group of people randomized to 2+ arms.2. Treatment strategiesMixing prevalent users and new users (1 study)Impossible to assign/randomize to “havingused drug A for X months”Not defining treatment strategies beyond “initiate drug A at baseline” (31 studies)Implied protocol leaves everything up to the treating physician and patient3. Assignment proceduresWeak substantive justification for confounder selection (31 studies)Broken randomization (due to insufficient emulation of randomization)4. Follow-upUnspecified follow-up duration in longitudinal analyses (5 studies)Infeasible to conceive an RCT with unspecified duration. Analysis results may lack interpretability.5. OutcomeJoint outcome of remaining on treatmentandhaving a good response, to avoid missingness (3 studies)Unusual outcome for RCT although technically possible.6. Causal contrasts (i.e., ITT or per-protocol effect)Failure to clarify the estimand (26 studies)Problem also common in RCTs7. Analysis planITT-type analysis among those with follow-upDeviates from the ITT principle (all randomized should be analysed)Per-protocol analyses did not account for post-baseline selection biasProblem also common in RCTs

Conclusion:

The majority of observational CER studies in RA have one or more design issues that may introduce bias. Target trial emulation is a structured approach for designing observational CER studies that helps to avoid common biases.

Disclosure of Interests:

Sizheng Steven Zhao: None declared, Houchen Lyu: None declared, Daniel Solomon Grant/research support from: Funding from Abbvie and Amgen unrelated to this work, Kazuki Yoshida: None declared

SAT0154 EXAMINATION OF CYP3A5 GENOTYPE IS USEFUL FOR INTRODUCTION OF TACROLIMUS TREATMENT IN OUTPATIENTS WITH RHEUMATIC DISEASES

Background:

Though several studies showed the efficacy of tacrolimus (TAC) in patients with rheumatoid arthritis (RA) in a dose-depending manner [1], the relationship between efficacy and concentration of TAC remained unclear. Genetic polymorphisms of cytochrome P450 (CYP) 3A5 were reported not only to play an important role in pharmacokinetics of TAC but also to have an influence on clinical outcomes in patients of rheumatic diseases. Several reports showed that the blood concentration of TAC in patients with a CYP3A5 *1 allele (EX, expressor) was lower than that of patients with a CYP3A5 *3/*3 (NEX, non-expressor) [2].

Objectives:

To assess the relationship between efficacy and concentration of TAC in patients with RA, and to examine the usefulness of CYP3A5 genotype screening to detect outpatients suitable for TAC treatment.

Methods:

We examined the relationship between disease activity score (DAS) 28-CRP and concentration of TAC in patients with RA. TAC was taken after the evening meal and blood samples were taken 12±4h after TAC administration. Next we investigated the relationship between genotype frequencies of CYP3A5 and concentration of TAC in patients with rheumatic disease without having renal dysfunction (eGFR<60) and also investigated the influence of concomitant drugs, such as strong inhibitors of CYP3A4/5 or metabolized by CYP3A4/5, to C/D value in each NEX and EX group. The blood concentration of TAC normalized to the corresponding dose per body weight (C/D, ng/ml per mg/kg) was analyzed according to genetic variation in CYP3A5. Furthermore we investigated the relationship between genotype frequencies of CYP3A5 and concentration of TAC in patients with rheumatic disease at first visit and second visit after starting TAC administration to assess the possibility for making rapid attainment of enough concentrations of TAC in early stage of treatment.

Results:

The concentration of TAC tended to be negatively correlated with the disease activity of RA. The C/D value in the NEX group (n=16) was 124.7±62.1, which was significantly higher than that in the EX group (n=23; 67.7±29.8;P<0.001). When comparing patients using concomitant drugs which are strong inhibitors of CYP3A4/5 or metabolized by CYP3A4/5 with patients not using those drugs, the each C/D value of NEX group was 122.9±52.3 (n=9) and 126.9±77.3 (n=7), and that of EX group was 71.3±32.2 (n=12) and 63.8±28.0 (n=11). There were no significant differences between these groups. In NEX group, when comparing concentration of TAC at first visit and second visit after starting TAC administration, the each concentration of TAC was 3.14±2.06 ng/ml and 3.80±2.20 ng/ml in NEX group (n=10), and that of TAC was 1.82±0.82 ng/ml and 2.69±1.52 ng/ml (n=11) in EX group (Figure).

Conclusion:

TAC showed efficacy in patients with RA in a concentration-dependent manner. EX patients may be impossible to achieve enough concentration of TAC even though using TAC of 3mg/day, approved dose for patients with RA in Japan, and NEX patients could make rapid attainment of enough concentrations of TAC in early stage of treatment, suggesting that we should consider induction of TAC only in NEX outpatients. Furthermore, drugs only slightly affected concentration of TAC in this study, suggesting that we can use TAC without any special attention to concomitant drugs.

References:

[1]Furst DE et al. Arthritis Rheum 2002;46:2020-28.

[2]Y. Muraki et al. Exp Ther Med 2018;15:532-38.

Acknowledgments:

none

Disclosure of Interests:

Soshi Takahashi: None declared, Shinji Horibata: None declared, Saori Hatachi: None declared, Miho Takahashi: None declared, Motoko Katayama: None declared, Saki Mukohara: None declared, Norihiko Amano: None declared, Katsuyuki Yoshida: None declared, Kennosuke Yorifuji: None declared, Shunichi Kumagai Grant/research support from: Astellas, Chugai, Mitsubishi Tanabe Co.Ltds, Consultant of: Sysmex Co.Ltd, Speakers bureau: many companies

FRI0246 GENOTYPING OF CYP3A5 IS USEFUL FOR TREATMENT WITH TACROLIMUS IN INTERSTITIAL LUNG DISEASE IN DERMATOMYOSITIS

Background:

Tacrolimus (TAC), an immunosuppressant, can be used in second-line maintenance therapy of interstitial lung disease (ILD) in patients with dermatomyositis (DM) [1]. In Japan, TAC is approved for DM-ILD and often used as induction therapy for severe cases, especially in patients with anti-MDA5-Ab (melanoma differentiation-associated gene 5 antibody) positive, in combination with glucocorticoids (GC) and intravenous cyclophosphamide (IVCY). Some studies reported the clinical efficacy of initial high-trough level TAC for DM-ILD in combination with GC and IVCY [2]. Adjustment to target concentration of TAC in early stage of treatment is important for controlling disease activity. The concentration of TAC depends on genetic polymorphisms in cytochrome P450 (CYP) 3A5 enzyme expression and several reports showed that the bioavailability and concentration of TAC in patients with a CYP3A5 *1 allele (*1) was lower than those with a CYP3A5 *3/*3 (*3/*3) [3].

Objectives:

To examine the usefulness of CYP3A5 polymorphisms in decision of initial dose to achieve the target concentration of TAC and to evaluate the clinical efficacy in patients of DM-ILD who achieved the enough concentration of TAC in early stage of treatment.

Methods:

We investigated CYP3A5 polymorphisms and TAC concentration in 9 patients of DM-ILD without renal dysfunction (eGFR>60). TAC was taken after both morning and evening meals and blood samples were taken 12h after TAC administration. The blood concentration of TAC normalized to the corresponding dose per body weight (C/D, ng/ml per mg/kg) was analyzed according to genetic variation in CYP3A5. Based on the retrospective analyzation, we chose proper dose of TAC in initial treatment for an anti-MDA5-Ab positive DM-ILD patient, whose genotype was *3/*3.

Results:

The C/D value in the *3/*3 group (n=6) was 154.6±25.6, which was significantly higher than that in the *1 group (n=3;79.0±2.8; P =0.028). When the target concentration was set at 5-10 ng/ml, the required dose was (0.0316 to 0.0633) mg/kg in the *1 group and (0.0162 to 0.0324) mg/kg in the *3/*3 group. The *1 group needs more dose than that of the *3/*3 group to achieve the same target trough of TAC, suggesting that the examination of CYP3A5 genotype is useful for deciding initial dose of TAC (Fig.1). We started TAC 6mg/day with setting target concentration at 15-20 ng/ml to a *3/*3 patient of DM-ILD with anti-MDA5-Ab positive, resulting in good clinical course with making rapid attainment of target concentration in early stage of treatment (Fig.2).

Conclusion:

To examine the CYP3A5 genotype is valuable for deciding the initial dose of TAC, especially in patients who need achievement to target concentration rapidly.

References:

[1]Oddis CV and Aggarwal R. Nat Rev Rheumatol 2018;14(5):279-89.

[2]Suzuka T et al. Int J Rheum dis 2019;22: 303-13.

[3]Y. Muraki et al. Exp Ther Med 2018;15:532-38.

Acknowledgments:

none

Disclosure of Interests:

motoko katayama: None declared, Shinji Horibata: None declared, Soshi Takahashi: None declared, Miho Takahashi: None declared, Saki Mukohara: None declared, Norihiko Amano: None declared, Katsuyuki Yoshida: None declared, Saori Hatachi: None declared, Kennosuke Yorifuji: None declared, Shunichi Kumagai Grant/research support from: Astellas, Chugai, Mitsubishi Tanabe Co.Ltds, Consultant of: Sysmex Co.Ltd, Speakers bureau: many companies

How Different is the Core of ^{25}F from ^{24}O_{g.s.} ?

The structure of a neutron-rich ^{25}F nucleus is investigated by a quasifree (p,2p) knockout reaction at 270A  MeV in inverse kinematics. The sum of spectroscopic factors of π0d_{5/2} orbital is found to be 1.0±0.3. However, the spectroscopic factor with residual ^{24}O nucleus being in the ground state is found to be only 0.36±0.13, while those in the excited state is 0.65±0.25. The result shows that the ^{24}O core of ^{25}F nucleus significantly differs from a free ^{24}O nucleus, and the core consists of ∼35% ^{24}O_{g.s.}. and ∼65% excited ^{24}O. The result may infer that the addition of the 0d_{5/2} proton considerably changes neutron structure in ^{25}F from that in ^{24}O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Individual response of humans to ionising radiation: governing factors and importance for radiological protection

Tissue reactions and stochastic effects after exposure to ionising radiation are variable between individuals but the factors and mechanisms governing individual responses are not well understood. Individual responses can be measured at different levels of biological organization and using different endpoints following varying doses of radiation, including: cancers, non-cancer diseases and mortality in the whole organism; normal tissue reactions after exposures; and, cellular endpoints such as chromosomal damage and molecular alterations. There is no doubt that many factors influence the responses of people to radiation to different degrees. In addition to the obvious general factors of radiation quality, dose, dose rate and the tissue (sub)volume irradiated, recognized and potential determining factors include age, sex, life style (e.g., smoking, diet, possibly body mass index), environmental factors, genetics and epigenetics, stochastic distribution of cellular events, and systemic comorbidities such as diabetes or viral infections. Genetic factors are commonly thought to be a substantial contributor to individual response to radiation. Apart from a small number of rare monogenic diseases such as ataxia telangiectasia, the inheritance of an abnormally responsive phenotype among a population of healthy individuals does not follow a classical Mendelian inheritance pattern. Rather it is considered to be a multi-factorial, complex trait.

Acetazolamide-Loaded Dynamic 7T MR Quantitative Susceptibility Mapping in Major Cerebral Artery Steno-Occlusive Disease: Comparison with PET

BACKGROUND AND PURPOSE

Dynamic changes in cerebrovascular reactivity after acetazolamide administration vary markedly among patients with major cerebral arterial steno-occlusive disease. MR quantitative susceptibility mapping can dynamically quantify the cerebral magnetic susceptibility. The purpose of this study was to determine whether dynamic changes in susceptibility after administration of acetazolamide on 7T quantitative susceptibility mapping are associated with pre-existing states of CBV and the cerebral metabolic rate of oxygen in the cerebral hemispheres with major cerebral arterial steno-occlusive disease.

MATERIALS AND METHODS

Sixty-five patients underwent 7T MR imaging at baseline and at 5, 10, 15, and 20 minutes after acetazolamide administration. Differences between the susceptibility of venous structures and surrounding brain tissue were calculated in the quantitative susceptibility mapping images. Susceptibility differences at 5, 10, 15, and 20 minutes after acetazolamide administration relative to baseline were calculated in 97 cerebral hemispheres with major cerebral arterial steno-occlusive disease. CBV and the cerebral metabolic rate of oxygen were also calculated using ¹⁵O-gas PET in the resting state.

RESULTS

Dynamic changes of susceptibility after acetazolamide administration were classified into 3 patterns: abnormally increasing 5 or 10 minutes after acetazolamide administration; abnormally decreasing within 20 minutes after acetazolamide administration; and remaining unchanged after acetazolamide administration. CBV was significantly greater in the first pattern than in the latter 2. The cerebral metabolic rate of oxygen differed significantly in descending order from the first to middle to last pattern.

CONCLUSIONS

Dynamic changes of susceptibility after acetazolamide administration on 7T MR quantitative susceptibility mapping are associated with pre-existing states of CBV and the cerebral metabolic rate of oxygen in major cerebral arterial steno-occlusive disease.

Swelling of Doubly Magic ^{48}Ca Core in Ca Isotopes beyond N=28

Interaction cross sections for ^{42-51}Ca on a carbon target at 280  MeV/nucleon have been measured for the first time. The neutron number dependence of derived root-mean-square matter radii shows a significant increase beyond the neutron magic number N=28. Furthermore, this enhancement of matter radii is much larger than that of the previously measured charge radii, indicating a novel growth in neutron skin thickness. A simple examination based on the Fermi-type distribution, and mean field calculations point out that this anomalous enhancement of the nuclear size beyond N=28 results from an enlargement of the core by a sudden increase in the surface diffuseness of the neutron density distribution, which implies the swelling of the bare ^{48}Ca core in Ca isotopes beyond N=28.

P1245 Huge left atrial myxoma masks mitral regurgitation

A 61-year-old gentleman, he had shortness of breath while few weeks and getting worse, was presented to our hospital. His oxygen saturation was 94 %(O2 5L) and no crackles or rales were heard. His electrocardiogram was sinus tachycardia, and chest X-ray showed cardiomegaly and BNP level was elevated (260.3pg/mL). Transthoracic echocardiography (TTE) revealed huge mass(57 × 39mm) occupying left atrium (LA), the mass was flexible in cardiac cycle and prolapsing from LA to left ventricle, it seems like cardiac myxoma. We suspected mitral stenosis (MS) caused by the mass (peak trans mitral flow velocity 3.1m/s), mitral regurgitation(MR) was not significant, and moderate tricuspid regurgitation with pulmonary hypertension (peak systolic pressure 61 mmHg). We performed transesophageal echocardiography(TEE) and CT angiography revealed the mass at fossa ovalis, we decided surgery of removing the mass considering the risk of mitral annulus obstruction and embolism. Intraoperative findings, after taken off the mass, TEE showed moderate to severe MR not detected preoperative TEE. Additionally, it revealed the mitral annulus enlargement(42 × 38mm by 2D TEE) and may gradually induced by prolapsing the mass. Finally, surgery for mitral valve was performed and postoperative TTE showed no MR. The mass was diagnosed cardiac myxoma by pathology.

MS is relatively common in patients with prolapsing LA myxoma , and it improves after removing the mass. In this case, mitral valve was no degeneration but enlarged mitral annulus and significantly MR had revealed after removing the mass. Keep in mind that there is possibility to underestimate of MR associated with LA myxoma. To take care of mitral valve complex sufficiently in such case, and to detect these findings at preoperative echocardiography, then more useful assessment for surgery.

Abstract P1245 Figure. Huge Left Atrial Myxoma Masks MR

Cross-section measurement in the reactions of 136Xe on proton, deuteron and carbon

The isotopic production cross sections for the reactions of 136Xe induced by proton, deuteron and carbon at 168 MeV/u were obtained by using the inverse kinematics technique at RIKEN Radioactive Isotope Beam Factory. The target dependence of the cross sections was investigated systematically. It was found that for the light-mass products, the cross sections on carbon are larger than those on deuteron and proton. The measured cross sections on proton were compared with the previous data at higher reaction energies to study the energy dependence. The experimental results were compared with the theoretical calculations including both the intranuclear cascade and evaporation processes using PHITS and with the EPAX and SPACS empirical parameterizations.

Location of the Neutron Dripline at Fluorine and Neon

A search for the heaviest isotopes of fluorine, neon, and sodium was conducted by fragmentation of an intense ^{48}Ca beam at 345  MeV/nucleon with a 20-mm-thick beryllium target and identification of isotopes in the large-acceptance separator BigRIPS at the RIKEN Radioactive Isotope Beam Factory. No events were observed for ^{32,33}F, ^{35,36}Ne, and ^{38}Na and only one event for ^{39}Na after extensive running. Comparison with predicted yields excludes the existence of bound states of these unobserved isotopes with high confidence levels. The present work indicates that ^{31}F and ^{34}Ne are the heaviest bound isotopes of fluorine and neon, respectively. The neutron dripline has thus been experimentally confirmed up to neon for the first time since ^{24}O was confirmed to be the dripline nucleus nearly 20 years ago. These data provide new keys to understanding the nuclear stability at extremely neutron-rich conditions.

Factors predictive of the presence of a CSF1R mutation in patients with leukoencephalopathy

Background and purpose

The purpose was to identify statistically factors that correlate with the presence of a colony‐stimulating factor 1 receptor (CSF1R) mutation and to reevaluate the accuracy of the current diagnostic criteria for CSF1R‐related leukoencephalopathy.

Methods

CSF1R testing was conducted on 145 consecutive leukoencephalopathy cases who were clinically suspected of having adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia. From these, 135 cases whose detailed clinical information was available were enrolled. Forward logistic stepwise regression was performed to generate a probability model to predict a positive CSF1R mutation result. The current diagnostic criteria were also applied to our cohort and their sensitivity and specificity were calculated.

Results

Twenty‐eight CSF1R‐mutation‐positive cases and 107 CSF1R‐mutation‐negative cases were identified. Our probability model suggested that factors raising the probability of a CSF1R‐mutation‐positive result were younger onset, parkinsonism, thinning of the corpus callosum and diffusion‐restricted lesions. It also showed that involuntary movements and brainstem or cerebellar atrophy were negative predictors of a CSF1R‐mutation‐positive result. In our cohort, the sensitivity and specificity for ‘probable’ or ‘possible’ CSF1R‐related leukoencephalopathy were 81% and 14%, respectively.

Conclusions

Clinical and brain imaging features predictive of the presence of a CSF1R mutation are proposed. Consideration of these factors will help prioritize patients for CSF1R testing.

Quasifree Neutron Knockout from ^{54}Ca Corroborates Arising N=34 Neutron Magic Number

Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a ^{54}Ca beam striking on a liquid hydrogen target at ∼200  MeV/u. A significantly larger cross section to the p_{3/2} state compared to the f_{5/2} state observed in the excitation of ^{53}Ca provides direct evidence for the nature of the N=34 shell closure. This finding corroborates the arising of a new shell closure in neutron-rich calcium isotopes. The distorted-wave impulse approximation reaction formalism with shell model calculations using the effective GXPF1Bs interaction and ab initio calculations concur our experimental findings. Obtained transverse and parallel momentum distributions demonstrate the sensitivity of quasifree one-neutron knockout in inverse kinematics on a thick liquid hydrogen target with the reaction vertex reconstructed to final state spin-parity assignments.

P4691Chronic blockade of toll-like receptor 9 ameliorated pulmonary arterial hypertension by reducing perivascular inflammation in rats

Background/Introduction

Perivascular inflammation plays an important role in the pathogenesis of pulmonary arterial hypertension (PAH). Recent studies have demonstrated that damaged mitochondrial DNA induces sterile inflammation by activating toll-like receptor (TLR)9 in spontaneous hypertensive rats. However, it remains unclear whether TLR9 is involved in perivascular inflammation and subsequent development of PAH.

Purpose

The purpose of the present study is to investigate whether chronic inhibition of TLR9 can ameliorate monocrotaline (MCT)-induced PAH in rats.

Methods

Male Sprague-Dawley rats were injected with MCT (60 mg/kg). First, we conducted immunohistochemistory to examine which cell types express TLR9 in lungs of normal rats and MCT-exposed rats. Second, we extracted cell-free DNA from plasma of rats and amplified genes of COX2 by real-time PCR to detect circulating cell-free mitochondrial DNA, a ligand of TLR9. Third, the administration of a selective TLR9 inhibitor (E6446, 10mg/kg/day, drinking water) or non-selective TLR9 inhibitor (chloroquine: 50mg/kg/day, ip) started three days before MCT injection and sacrificed on day 21. We assessed hemodynamic data and histopathological analysis (EVG stain for medial wall thickness (MWT) in pulmonary arteries (outer diameter: 50 ∼ 100 μm) and CD68 for macrophage accumulation around pulmonary arteries (outer diameter: <50 μm)), and measured the levels of interleukin-6 (IL-6) in lungs by real time PCR. Finally, we investigated survival rate in the reversal protocol, where we started the administration of E6446 on day 14.

Results

TLR9 was expressed dominantly in pulmonary endothelial cells and macrophages in the lungs of both normal rats and MCT-exposed rats. Compared with normal rats, MCT-exposed rats showed increased gene expression of COX2 (0.048±0.001 vs. 0.052±0.001 expressed by 1/Ct) in plasma on day 14. MCT-exposed rats also had increased right ventricular systolic pressure (RVSP: 21±1 vs. 60±2 mmHg), total pulmonary vascular resistance index (TPRI: 0.07±0.01 vs. 0.43±0.02 mmHg/min/mL/kg), MWT (0.07±0.01 vs. 0.26±0,02) and accumulation of macrophages (1.6±0.3 vs. 20.0±1.7 cells/HPF) on day 21. In the prevention protocol, either E6446 or chloroquine significantly prevented the elevations of RVSP (49±4 or 48±3 mmHg) and TPRI (0.29±0.04 or 0.27±0.03 mmHg/min/mL/kg) with reducing MWT (0.18±0.01 or 0.18±0.01) and macrophage accumulation (9.7±1.3 or 9.8±2.5 cell/HPF) on day 21. In addition, these drugs significantly reduced the levels of IL-6 mRNA compared with MCT group (4.4±1.0 or 4.8±1.4 vs. 11.9±1.0). In the reversal protocol, the treatment of E6446 had significantly increased the survival rate (50 vs. 10%).

Conclusions

TLR9 largely contributes to the development of PAH by reducing perivascular inflammation. Inhibition of TLR9 could be a novel therapeutic target for PAH.

Identification of the Bleeding Point in Hemorrhagic Moyamoya Disease Using Fusion Images of Susceptibility-Weighted Imaging and Time-of-Flight MRA

BACKGROUND AND PURPOSE

The location of intracerebral hemorrhage in Moyamoya disease is a prognostic factor for rebleeding and the degree of preventive effects obtainable with bypass surgery. We evaluated whether the bleeding point and responsible vessel were detectable using fusion images of SWI and time-of-flight MRA performed during chronic-phase hemorrhage.

MATERIALS AND METHODS

We retrospectively enrolled 42 patients with hemorrhagic Moyamoya disease (48 hemorrhagic events). Fusion images of SWI and MRA were made using workstations, and we defined the bleeding point as the point at which the signal of an abnormally extended artery on MRA overlapped the hypointense area on SWI. Two independent raters identified the bleeding point, and classified the location and responsible vessels.

RESULTS

The bleeding point was detectable at a frequency of 79.2% by rater 1. Agreement for the presence of a bleeding point was high (interrater κ = 0.83; 95% CI, 0.65-1; intrarater κ = 0.86; 95% CI, 0.68-1). The frequency of a periventricular location of the bleeding point was 65.8% by rater 1, and agreement on the location was again high (interrater κ = 0.92; 95% CI, 0.82-1; intrarater κ = 0.85; 95% CI, 0.72-0.99). The choroidal artery was the most frequent responsible vessel (57.9% by rater 1), and agreement on the responsible vessel was high (interrater κ = 0.84; 95% CI, 0.69-1; intrarater κ = 0.90; 95% CI, 0.78-1).

CONCLUSIONS

Detection of the bleeding point in hemorrhagic Moyamoya disease using SWI and MRA fusion images offers highly reproducible results.

Progesterone signaling during pregnancy in the lab opossum, Monodelphis domestica

To investigate subtle pregnancy-associated changes in the lab opossum, Monodelphis domestica, an induced ovulator, we compared pregnant with non-pregnant and pseudopregnant animals with regard to serum P₄ levels and progesterone receptor (PR) expression. Using video-verified, time-mated lab opossums as sources of biological material, we compared ovaries, uteri and sera obtained on odd-numbered days of the 14.5-day pregnancy in this animal. Females that mated successfully but did not produce embryos were classified as pseudopregnant. P₄ levels differed significantly between pregnant (N = 21) and either non-pregnant (N = 3) or pseudopregnant (N = 3) opossums, but not between the non-pregnant and pseudopregnant groups. A significant decline in serum P₄ occurred between pregnancy days 3 and 5, coinciding with an elevated probability of pregnancy failure between days 5 and 9. PR was detected in the nuclei of uterine-gland epithelial cells on pregnancy days 5 and 7 as well as variably in the corpora lutea (CL) of animals on pregnancy days 3-11. PR expression in the CL suggests that P₄ may be autostimulatory in lab opossums and that certain levels of this steroid are required during normal pregnancy. The significant day-3 drop in P₄ may explain why pregnancy failure in this polyovular metatherian is likeliest to occur between days 5 and 9, an interval during which the extended period of blastocyst morphogenesis and expansion occurs. Taken together, these results suggest that P₄ may have unrecognized signaling roles not only in pregnancy but perhaps embryonic development as well in the lab opossum.