Identifying possible inaccuracy in reported birth head circumference measurements among infants in the US Zika Pregnancy and Infant Registry

The US Zika Pregnancy and Infant Registry (USZPIR) monitors infants born to mothers with confirmed or possible Zika virus (ZIKV) infection during pregnancy. The surveillance case definition for Zika-associated birth defects includes microcephaly based on head circumference (HC). We assessed birth and follow-up data from infants with birth HC measurements <3rd percentile and birthweight ≥10th percentile to determine possible misclassification of microcephaly.We developed a schema informed by literature review and expert opinion to identify possible HC measurement inaccuracy using HC growth velocity and neuroimaging results. Two or more HC measurements between 2-12 months of age were required for assessment. Inaccuracy in birth HC measurement was suspected if growth velocity was >3 centimeters/month in the first three months or HC was consistently >25th percentile during follow-up. Normal neuroimaging was considered supportive of HC measurement inaccuracy. Of 6,799 infants, 351 (5.2%) had Zika-associated birth defects, of which 111 had birth HC measurements <3rd percentile and birthweight ≥10th percentile. Of 84/111 infants with sufficient follow-up, 38/84 (45%) were classified as having possible inaccuracy of birth HC measurement, 19/84 (23%) had HC ≥3rd percentile on follow-up without meeting criteria for possible inaccuracy, and 27/84 (32%) had continued HC <3rd percentile. After excluding possible inaccuracies, the proportion of infants with Zika-associated birth defects including microcephaly decreased from 5.2% to 4.6%.About one-third of infants with Zika-associated birth defects had only microcephaly, but indications of possible measurement inaccuracy were common. Implementation of this schema in ZIKV infection during pregnancy studies can reduce misclassification of microcephaly.

EFFECT OF CU CONTENT AND GROWTH VELOCITY ON THE MICROSTRUCTURE PROPERTIES OF THE DIRECTIONALLY SOLIDIFIED AL-MN-CU TERNARY ALLOYS

In this work, influences of composition (Cu content) and growth velocity (V) on the microstructure (dendritic spacing) of Al–Mn–Cu ternary alloys have been investigated. Al–1.9Mn–xCu (x=0.5, 1.5 and 5 wt. %) alloys were prepared using metals of 99.90% high purity in the vacuum atmosphere. These alloys were directionally solidified upwards under various growth velocities (8.3–978 m/s) using a Bridgman-type directional solidification furnace at a constant temperature gradient (7.1 K/mm). Measurements of primary dendrite arm spacing () of the samples were carried out and then expressed as functions of growth velocity and Cu content. Especially, cell-dendritic transition was detected for low growth velocity (41.6 m/s) for alloys containing 0.5 and 1.5Cu. It has been found that the values of  decrease with increasing V and decreasing Cu content. Keywords: Aluminum alloys, Solidification, Cell-dendritic transition, Dendrite arm spacing

Mechanical Thrombectomy Up to 24 Hours in Large Vessel Occlusions and Infarct Velocity Assessment

Background We retrospectively compared early‐ (<6 hours) versus late‐ (6–24 hours) presenting patients using perfusion‐weighted imaging selection and evaluated clinical/radiographic outcomes. Methods and Results Large vessel occlusion patients treated with mechanical thrombectomy from August 2017 to July 2020 within 24 hours of onset were retrieved from a single‐center database. Perfusion‐weighted imaging was analyzed by automated software and final infarct volume was measured semi‐automatically within 14 days. The primary end point was good outcome (modified Rankin Scale 0–2 at 90 days). Secondary end points were excellent outcome (modified Rankin Scale 0–1 at 90 days), symptomatic intracranial hemorrhage, and death. Clinical characteristics/radiological values including hypoperfusion volume and infarct growth velocity (baseline volume/onset‐to‐image time) were compared between the groups. Of 1294 patients, 118 patients were included. The median age was 74 years, baseline National Institutes of Health Stroke Scale score was 14, and core volume was 13 mL. The late‐presenting group had more female patients (67% versus 31%, respectively; P =0.001). No statistically significant differences were seen in good outcome (42% versus 53%, respectively; P =0.30), excellent outcome (26% versus 32%, respectively; P =0.51), symptomatic intracranial hemorrhage (6.5% versus 4.6%, respectively; P =0.74), and death (3.2% versus 5.7%, respectively; P =0.58) between the groups. The late‐presenting group had more atherothrombotic cerebral infarction (19% versus 6%, respectively; P =0.03), smaller hypoperfusion volume (median: 77 versus 133 mL, respectively; P =0.04), and slower infarct growth velocity (median: 0.6 versus 5.1 mL/h, respectively; P =0.03). Conclusions Patients with early‐ and late‐time windows treated with mechanical thrombectomy by automated perfusion‐weighted imaging selection have similar outcomes, comparable with those in randomized trials, but different in infarct growth velocities. Registration URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02251665.

EB3-informed dynamics of the microtubule stabilizing cap during stalled growth

Microtubule stability is known to be governed by a stabilizing GTP/GDP-Pi cap, but the exact relation between growth velocity, GTP hydrolysis and catastrophes remains unclear. We investigate the dynamics of the stabilizing cap through in vitro reconstitution of microtubule dynamics in contact with micro-fabricated barriers, using the plus-end binding protein GFP-EB3 as a marker for the nucleotide state of the tip. The interaction of growing microtubules with steric objects is known to slow down microtubule growth and accelerate catastrophes. We show that the lifetime distributions of stalled microtubules, as well as the corresponding lifetime distributions of freely growing microtubules, can be fully described with a simple phenomenological 1D model based on noisy microtubule growth and a single EB3-dependent hydrolysis rate. This same model is furthermore capable of explaining both the previously reported mild catastrophe dependence on microtubule growth rates and the catastrophe statistics during tubulin washout experiments.

On the Relationship Between EB-3 Profiles and Microtubules Growth in Cultured Cells

Microtubules are dynamic structures undergoing rapid growth and shrinkage in living cells and in vitro. The growth of microtubules in vitro was analyzed with subpixel precision (Maurer et al., Current Biology, 2014, 24 (4), 372–384); however, to what extent these results could be applied for microtubules growing in vivo remains largely unknown. Particularly, the question is whether microtubule growth velocity in cells could be sufficiently approximated by a Gaussian distribution or its variability requires a more sophisticated description? Addressing this question, we used time-lapse microscopy and mathematical modeling, and we analyzed EB-3 comets forming on microtubules of cultured cells with subpixel precision. Parameters of comets (shape, form, and velocity) were used as topological characteristics of 3D voxel objects. Using regression analysis, we determined the real positions of the microtubule tips in time-lapse sequences. By exponential decay fitting of the restored comet intensity profile, we found that in vivo EB-3 rapidly exchanges on growing microtubule ends with a decoration time ∼ 2 s. We next developed the model showing that the best correlation between comet length and microtubule end growth velocity is at time intervals close to the decoration time. In the cells, EB comet length positively correlates with microtubule growth velocity in preceding time intervals, while demonstrating no correlation in subsequent time intervals. Correlation between comet length and instantaneous growth velocity of microtubules remains under nocodazole treatment when mean values of both parameters decrease. Our data show that the growth of microtubules in living cells is well-approximated by a constant velocity with large stochastic fluctuations.

A Prospective Observational Multicenter Study on Deferiprone & Deferasirox in Clinical Practice of Pediatric Patients with Transfusion-Dependent B-Thalassemia

Background: Iron overload is inevitable but a manageable complication of frequent blood transfusion, the effectiveness and safety of two iron chelation therapy in young children with transfusion-dependent B thalassemia (TDB-T) using either deferiprone (DFP) or deferasirox (DFX) were well studied in clinical trials. The primary objectives were; reporting efficacy and frequency of all adverse events (AEs) as compared with published data. Secondary objective was reporting deviation from guidelines, The analysis of clinical data is the first step to design new strategies Methodology: An investigator initiated 2-year multicenter prospective study enrolling over 6 months period; 302 children with TDB-T from 11 centers; keeping pre-transfusion Hb &gt;8gm/dl. When serum ferritin (SF) reached around 1000 ng/ml; they had received according to availability; either DFP liquid solution in a dose; 75 mg/kg/day (n=62) or DFX (n=240); (dispersed tablet; 25% or film-coated tablet 75% in a dose; 20-25 mg/kg/d or its equivalent). CBC was done biweekly in DFP and pre-transfusion in DFX group. Liver transaminases, serum creatinine and (SF) were done /3 months. Changes in growth velocity over time were documented. Results: 66% were males, age at enrolment was; (11-19 and 14-26 months) in DFP and DFX respectively; they had received (6-8) and (7-11) transfusions prior to chelation in both groups respectively in addition to (16-21) during the study. 20% of patients did not achieve the target pre-transfusion Hb level. At initiation of DFP; SF median; 960 (IQR; 122 ng/ml) while those on DFX had SF; median 1070 (IQR 138 ng/ml) both groups had comparable transfusion iron input during the study. At 24 months of regular transfusion-chelation; SF &lt; 1000 ng/ml was noticed in 65% and 60% of the patients respectively with good growth velocity in children using either chelator. Unnecessary over-dosing of DFX &gt; 40 mg/kg was observed in 5%, meanwhile 3.2% had received DFP in a dose &gt;75-100 mg/kg while SF was &lt;1500 ng/ml. Under-reporting of adverse events in both groups was observed; 5% GIT upset, neither arthralgia nor agranulocytosis, neutropenia (3.2%) in DFP group and CBC was not checked biweekly; but only prior to transfusion. 4-5 % had elevated transaminases in both chelators, while patients on DFX reported; GIT upset in 4.2% and rash in 1.6%. Elevated serum creatinine &gt; 33% from baseline on 2 successive visits was observed in 5% in DFX without reducing the dose or re-check. No unexpected, serious severe adverse events were reported in both groups. Poorly controlled patients with SF &gt; 1500 ng /ml at 12 or 24 months were 12, 8% in DFP group; in contrast to 15%, 10% in DFX group respectively; with no statistical difference; (compliance was comparable). The total DFP and DFX discontinuation ratio was 5% in each group. Conclusion: infants and young children with TDB-T naïve to chelation were put on mono-therapy at younger age than reported before. Both chelators were effective, well tolerated and with no severe safety concerns; however deviation from guidelines was observed as; unnecessary over-dosing of DFX and under-reporting of AEs in both groups in real life practice. Disclosures Hamdy: ApoPharma: Honoraria; Amgen: Honoraria; Bayer: Honoraria; Novartis: Honoraria; NovoNordisk: Honoraria; Roche: Honoraria; Takeda: Honoraria.

A Prospective Randomized Multicenter Trial Using Either Deferiprone or Deferasirox after an Early Start of Deferiprone or Placebo in Young Children Newly Diagnosed with Transfusion-Dependent Beta-Thalassemia

Iron overload is a potentially preventable complication of blood transfusion dependency. The effectiveness and safety of early start of iron chelation therapy in young children with transfusion-dependent Beta-thalassemia (TDB-T) prior to development of iron overload have been recently demonstrated. The aim of this study was to evaluate the long term effectiveness and safety of continued iron chelation in these children. Methodology: This is a multi-center, investigator initiated, one year prospective randomized study of children with TDB-T who completed the randomized START study (NCT03591575), which had evaluated the safety and efficacy of the oral iron chelator (DFP) in children who did not yet meet the criteria for starting chelation therapy as per standard practice. Enrolment is shown in follow-up chart below; 48 children with TDBT from 3 centers were eligible to be enrolled and were randomized in 1:1 ratio to receive either DFP (n=23) or deferasirox (DFX) (n=25). Half of patients in this study were naïve to chelation (on placebo in START study); had received DFP at a dose; 75 mg/kg/ day or DFX in a dose; 20-25mg/kg/d in 2:1 ratio respectively, while those on DFP in START had continued on either DFP or DFX in 1:2 ratio with same doses. Patients were kept on regular transfusion to keep pre-transfusion Hb &gt;8gm/dl. The primary endpoint was safety and secondary endpoints were changes in serum ferritin (SF) and growth enhancement (height, weight) both were assessed quarterly. An informed consent was signed by parents of all patients before start of the study. Statistical significance between DFP and DFX treated groups was calculated via t-test for continuous variables and Fisher's exact test for discrete variables. Results: In the current study; 66% of the children were males, at enrolment; their age ranged from 20-68 (median 38) months; those who were on DFP or placebo in START had received comparable transfusion units (median 11 and 9 respectively) and SF (880 and 1150 ng/ml respectively). At 12 month of continuation on iron chelation 22% and 60% of children on DFP vs 12% and 48% of those on DFX had SF&lt;500 ng/ml or 500- &lt;1000 ng/ml, respectively (p value &lt;0.05);. TDB-T initiated and continued on DFP had the best growth velocity; all had annual growth velocity &gt;5cm (p value &lt;0.01), as well as a significant lower final SF (P value &lt; 0.01). Adverse events were mild and uncommon in both groups. There were no episodes of arthralgia or agranulocytosis in either group. Elevated serum creatinine &gt; 33% from baseline on 2 successive visits were observed in 0% in DFP vs. 12% in DFX. No unexpected, serious, or severe AEs were reported in both groups. Conclusion: Children with TDB-T whether on DFP or DFX showed uncommon mild AEs, with no serious or severe AEs. Patients on DFP after an early start of DFP showed adequate growth velocity and better control of iron-overload on serial measurement of SF; compared with those who were on placebo. Figure 1 Figure 1. Disclosures Hamdy: ApoPharma: Honoraria; Amgen: Honoraria; Bayer: Honoraria; Novartis: Honoraria; NovoNordisk: Honoraria; Roche: Honoraria; Takeda: Honoraria.