International Online Survey on the Management of Patent Ductus Arteriosus

INTRODUCTION

There is uncertainty and lack of consensus regarding optimal management of patent ductus arteriosus (PDA). We aimed to determine current clinical practice in PDA management across a range of different regions internationally.

MATERIALS AND METHODS

We surveyed PDA management practices in neonatal intensive care units using a pre-piloted web-based survey, which was distributed to perinatal societies in 31 countries. The survey was available online from March 2018 to March 2019.

RESULTS

There were 812 responses. The majority of clinicians (54%) did not have institutional protocols for PDA treatment, and 42% reported variable management within their own unit. Among infants <28 weeks (or <1,000 g), most clinicians (60%) treat symptomatically. Respondents in Australasia were more likely to treat PDA pre-symptomatically (44% vs. 18% all countries [OR 4.1; 95% CI 2.6-6.5; p < 0.001]), and respondents from North America were more likely to treat symptomatic PDA (67% vs. 60% all countries [OR 2.0; 95% CI 1.5-2.6; p < 0.001]). In infants ≥28 weeks (or ≥1,000 g), most clinicians (54%) treat symptomatically. Respondents in North America were more likely to treat PDAs in this group of infants conservatively (47% vs. 38% all countries [OR 2.3; 95% CI 1.7-3.2; p < 0.001]), and respondents from Asia were more likely to treat the PDA pre-symptomatically (21% vs. 7% all countries [OR 5.5; 95% CI 3.2-9.8; p < 0.001]).

DISCUSSION/CONCLUSION

There were marked international differences in clinical practice, highlighting ongoing uncertainty and a lack of consensus regarding PDA management. An international conglomeration to coordinate research that prioritises and addresses these areas of contention is indicated.

Evaluation of neonatal cerebral perfusion using three-dimensional power Doppler ultrasound volumes

AIM

Despite improvement in preterm survival, neurological morbidity remains high. 3D fractional moving blood volume (3D-FMBV) quantifies neonatal cerebral perfusion by calculating a standardised measure of the amount of moving blood in a region of interest and correlates with tissue perfusion in animal studies. However, its feasibility and reproducibility are yet to be assessed in newborn infants.

METHODS

Fractional moving blood volume analysis was performed on three-dimensional power Doppler ultrasound (PD-US) volumes from a cohort of preterm infants recruited in 2015 from the Royal Hospital for Women Neonatal Intensive Care Unit. The volumes were acquired by two sonographers and analysed by two different observers. The 3D-FMBV algorithm was applied to calculate an estimate for perfusion. Reproducibility and agreement were assessed using intra-class correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

All 3D PD-US volumes were analysed successfully. Intra-observer reliability was excellent with an ICC of 0.907 (95% CI 0.751-0.968) and 0.906 (95% CI 0.741-0.967) for two independent observers respectively. The inter-observer reliability of the entire technique was good with an ICC of 0.752 (CI: 0.404-0.909).

CONCLUSION

We have successfully shown the feasibility and reliability of applying the 3D-FMBV technique to the neonatal brain in a healthy preterm population.

Survival prediction modelling in extreme prematurity: are days important?

OBJECTIVE

To demonstrate that days are important in extreme prematurity when creating survival prediction models based on gestation.

STUDY DESIGN

Prospectively collected data were analysed for all admitted infants born 23 + 0 to 27 + 6 weeks gestation in the Australian and New Zealand Neonatal Network from 2009 to 2016. The effect of days on observed survival rates was assessed using a non-parametric test for trend. Prediction models created based on gestational age in completed weeks only or weeks plus days were compared.

RESULT

Seven thousand eight hundred and thirty-six extreme preterm infants were studied. Observed survival increased with days for 23, 24, 25, and 27 weeks gestational age (P = 0.01; P < 0.001; P = 0.003; P = 0.003) but not for 26 weeks (P = 0.19). A survival prediction model based on weeks and days performed better than completed weeks only (AUC 0.722 vs 0.712; P < 0.001).

CONCLUSION

In extreme prematurity, survival estimate accuracy improves when survival prediction models include days in addition to weeks.

Trial of aerosolised surfactant for preterm infants with respiratory distress syndrome

OBJECTIVE

To evaluate the safety of an aerosolised surfactant, SF-RI 1, administered via nasal continuous positive airway pressure (nCPAP) and a prototype breath synchronisation device (AeroFact), to preterm infants with respiratory distress syndrome (RDS).

DESIGN

Multicentre, open-label, dose-escalation study with historical controls.

SETTING

Newborn intensive care units at Mater Mothers' Hospital, Brisbane, and Royal Hospital for Women, Sydney, Australia.

PATIENTS

Infants 26 weeks through 30 weeks gestation who required nCPAP 6-8 cmH₂O and fraction of inspired oxygen (FiO₂) <0.30 at <2 hours of age.

INTERVENTIONS

In part 1, infants received a single dose of 216 mg/kg of aerosolised surfactant. In part 2, infants could receive up to four doses of aerosolised surfactant. Three historical control infants were matched for each enrolled infant.

MAIN OUTCOME MEASURES

Treatment failure was defined as Respiratory Severity Score (FiO₂×cmH₂O nCPAP) >2.4, nCPAP >8 cmH₂O, arterial carbon dioxide >65 mm Hg, pH <7.20 or three severe apnoeas within 6 hours during the first 72 hours of life. Other outcomes included tolerance of the AeroFact treatment and complications of prematurity.

RESULTS

10 infants were enrolled in part 1 and 21 in part 2 and were compared with 93 historical controls. No safety issues were identified. In part 2, 6 of 21 (29%) AeroFact-treated infants compared with 30 of 63 (48%) control infants met failure criteria. Kaplan-Meier analysis of patients in part 2 showed a trend towards decreased rate of study failure in the AeroFact-treated infants compared with historical controls (p=0.10).

CONCLUSION

The AeroFact system can safely deliver aerosolised surfactant to preterm infants with RDS who are on nCPAP.

TRIAL REGISTRATION NUMBER

ACTRN12617001458325.

When should intensive care be provided for the extremely preterm infants born at the margin of viability? A survey of Australasian parents and clinicians

AIM

This study aimed to explore clinician and parent opinions of risk limits on resuscitation and intensive care (IC) for extremely premature infants born at the margin of viability.

METHODS

Two anonymous on-line surveys were conducted from August 2016 to January 2017. Survey participants were: (i) clinicians affiliated with neonatal intensive care units in Australia; and (ii) parents or individuals who expressed interest in premature babies through the Facebook page of Miracle Babies Foundation.

RESULTS

A total of 961 responses were received. Among 204 clinicians, 52% were neonatologists, 22% obstetricians, 20% neonatal intensive care unit nurses and 4% were midwives. Among 757 parents, 98% had a premature baby. Only 75% of clinicians responded to the risk limits questions. Median mortality risk above which they would not recommend resuscitation/IC was 70% (interquartile range (IQR) 50-80%); major disability risk in survivors 60% (IQR 50-75%); and composite risk of mortality and major disability 70% (IQR 50-80%). All parents answered the risk limit questions. The median mortality risk for not planning resuscitation was 90% (IQR 60-90%); major disability risk in survivors 50% (IQR 30-90%); and composite risk 90% (IQR 50-90%). Most clinicians (82%) stated that decisions should be guided by parent opinions if there are uncertainties. Parents had varying perception of previous counselling, and 57% stated that both their viewpoint and doctor's predicted risk influenced their decision-making.

CONCLUSIONS

Clinicians and parents had different views on mortality and major disability risks when deciding on resuscitation/neonatal IC treatment. When there was uncertainty, both agreed on working together.

OP0166 ALTERNATIVE RENAL RESPONSE DEFINITIONS IN A RANDOMIZED, CONTROLLED TRIAL OF OBINUTUZUMAB FOR PROLIFERATIVE LUPUS NEPHRITIS

Background:

Obinutuzumab, a type II anti-CD20 mAb, resulted in rapid and complete B-cell depletion and improved renal responses in proliferative lupus nephritis (LN) in the Phase 2 NOBILITY trial and will be further evaluated in the Phase 3 REGENCY trial. Recent analyses suggest alternative urinary sediment, serum creatinine (SCr), and urine protein/creatinine ratio (UPCR) requirements may be better measures of response in LN than those used in NOBILITY [1,2].

Objectives:

To evaluate the NOBILITY response definitions and to report the results of NOBILITY using alternative definitions of renal response.

Methods:

126 patients with active Class III/IV LN were randomized to obinutuzumab or placebo in combination with mycophenolate and glucocorticoids. NOBILITY complete renal response (CRR) required UPCR < 0.5, SCr ≤ the upper limit of normal (ULN) of the reference laboratory and not increased > 15% from baseline SCr, and inactive urinary sediment. Exploratory analyses were conducted, and alternative response definitions were evaluated post hoc.

Results:

NOBILITY CRR was increased with obinutuzumab over placebo at Week 52 (35% vs. 23%, P = 0.11) and Week 76 (40% vs. 18%, P = 0.007). Response rates were low among patients with baseline SCr < 0.65 mg/dL (n = 45) due to the requirement that SCr not increase > 15% from baseline; increasing this threshold to 25% increased the response rate to a level similar to other groups (Figure). Alternative response definitions demonstrated increased rates of response in both treatment groups and similar benefits of obinutuzumab over placebo at Weeks 52 and 76 (Table).

Conclusion:

Obinutuzumab resulted in consistent treatment benefits across a range of renal response definitions in NOBILITY and will be further evaluated in REGENCY. A requirement that SCr not increase > 15% from baseline may be overly restrictive in patients with low baseline SCr (< 0.65 mg/dL), where a change of 15% represents < 0.1 mg/dL and is of questionable clinical relevance. These findings may inform LN clinical trial design and more accurately reflect clinical practice.

References:

[1]Dall’era M et al.Arthritis Rheumatol. 2015;67:1305-13.

[2]Almaani S et al.J Am Soc Nephrol. 2019;30:669 [abstract].

Table.

Data from NOBILITY at weeks 52 and 76 using several response definitions

Definition of responseWeek 52Week 76OBI (n = 63)PBO (n = 62)Diff.OBI (n = 63)PBO (n = 62)Diff.NOBILITY complete responseUPCR < 0.5, SCr ≤ ULN and not increased > 15% from baseline SCr, and < 10 RBC/hpf without casts35%23%12%*40%18%22%**REGENCY complete responseUPCR < 0.5, SCr ≤ ULN and not increased > 25% from baseline SCr43%29%14%*54%31%23%**UPCR < 0.8 only64%48%15%*64%47%17%*UPCR < 0.8 with SCr requirementUPCR < 0.8 and SCr ≤ ULNornot increased > 15% from baseline SCr60%48%12%*64%45%18%**NOBILITY overall responseCRR or ≥ 50% reduction in UPCRawith SCr not increased > 15% from baseline and urinary RBCs not increased > 50% from baseline56%36%20%**51%29%22%**REGENCY overall responseCRR or ≥ 50% reduction in UPCRawith SCr not increased > 25% from baseline68%45%23%**67%50%17%**

OBI, obinutuzumab; PBO, placebo.

* P < 0.2 vs. placebo group. ** P < 0.05 vs. placebo group.

a≥ 50% reduction in UPCR to a value < 1 (< 3 if the baseline UPCR was ≥ 3). All response definitions required no use of rescue medications or early withdrawal.

Acknowledgments:

This study was funded by F. Hoffmann-La Roche.

Disclosure of Interests:

Zahir Amoura Grant/research support from: GSK, Roche, Consultant of: GSK, Astra Zeneca, Amgen, Philippe Rémy: None declared, Luis Fernando Quintana Porras: None declared, Laurent Chiche: None declared, Dominique Chauveau: None declared, Dario Roccatello: None declared, Richard Furie Grant/research support from: AstraZeneca, Biogen, Consultant of: AstraZeneca, Biogen, Thomas Schindler Employee of: F. Hoffmann-La Roche, Jay Garg Employee of: Genentech, Matthew D. Cascino Employee of: Genentech, Brad H Rovin Grant/research support from: GSK, Consultant of: GSK, Andrea Doria Consultant of: GSK, Pfizer, Abbvie, Novartis, Ely Lilly, Speakers bureau: UCB pharma, GSK, Pfizer, Janssen, Abbvie, Novartis, Ely Lilly, BMS

PARE0009 COMMUNITY ADVISORY BOARD INPUT CAN MAKE LAY SUMMARIES OF CLINICAL TRIAL RESULTS MORE UNDERSTANDABLE

Background:

Under European Union (EU) Clinical Trial regulations,1clinical research sponsors (CRSs) must ensure all studies performed in the EU are accompanied by a trial summary for laypersons, published within 1 year of study completion. These lay summaries should disseminate clinical trial results in an easy-to-understand way for trial participants, patient and caregiver communities, and the general public. The European Patients Forum (EPF)2and European Patients’ Academy on Therapeutic Innovation (EUPATI)3encourage CRSs to engage with patient organisations (POs) in the development of lay summaries. This recognises the patients’ contribution to clinical research and supports the development of patient-focused material.

Objectives:

We share learnings from a collaboration between scleroderma POs and a CRS to create the SENSCIS® trial (NCT02597933) written and video lay summaries.

Methods:

A community advisory board (CAB), comprising representatives from 11 scleroderma POs covering a range of countries/regions, was formed based on the EURORDIS charter for collaboration in clinical research.4Through three structured meetings, over a seven-month period, the CAB provided advice on lay summary materials (written and video) drafted by the CRS’ Lay Summary Group (Fig. 1). At each review cycle, the CAB advice was addressed to make content more understandable and more relevant for patients and the general public.

Results:

The CAB advised that the existence of lay summaries is not well known in the patient community and also recommended the development of trial-specific lay summary videos to further improve understandability of the clinical trial results for the general public. Videos are a key channel of communication, enabling access to information for people with specific health needs and lower literacy levels. Following CAB advice, the CRS developed a stand-alone video entitled“What are lay summaries?”and a trial-specific lay summary video. Revisions to lay summary content (written and video) included colour schemes, iconography and language changes to make content more understandable. For videos, adjustments to animation speed, script and voiceover were implemented to improve clarity and flow of information (Fig. 2). Approved final versions of lay summary materials are publicly available on the CRS website. Translation into languages representing trial-site countries is in progress to widen access to non-English speakers and, where possible, local versions are being reviewed by the patient community.

Conclusion:

Structured collection and implementation of CAB advice can make lay summary materials more understandable for the patient community and wider general public.

References:

[1]EU. Summaries of clinical trial results for laypersons. 2018

[2]EPF. EPF position: clinical trial results – communication of the lay summary. 2015

[3]EUPATI. Guidance for patient involvement in ethical review of clinical trials. 2018

[4]EURORDIS. Charter for Collaboration in Clinical Research in Rare Diseases. 2009

Disclosure of Interests:

Joep Welling Speakers bureau: Four times as a patient advocate for employees of BII and BI MIDI with a fixed amount of € 150,00 per occasion., Annelise Roennow: None declared, Maureen Sauvé Grant/research support from: Educational grants from Boehringer Ingelheim and Janssen., EDITH BROWN: None declared, Ilaria Galetti: None declared, Alex Gonzalez Consultant of: Payment made to the patient organisation (Scleroderma Research Foundation) for participation in advisory boards, Alexandra Paula Portales Guiraud: None declared, Ann Kennedy Grant/research support from: AS FESCA aisbl, Catarina Leite: None declared, Robert J. Riggs: None declared, Alison Zheng Grant/research support from: We get grants from Lorem Vascular; BI China,; Jianke Pharmaceutical Co., Ltd.; Kangjing Biological Co., Ltd.; COFCO Coca-Cola to organize national scleroderma meetings, offer patients service, holding academic meetings and other public activities, there is also a small part of the grants used to pay the workers in our organization., Consultant of: I worked as a paid consultant for BI. Pay-per-job., Speakers bureau: I was invited once to be a speaker at BI China’s internal meeting and they paid me., Matea Perkovic Popovic: None declared, Annie Gilbert Consultant of: I have worked as a paid consultant with BI International for over 3 years, since Sept 2016., Lizette Moros Employee of: Lizette Moros is an employee of Boehringer Ingelheim, Kamila Sroka-Saidi Employee of: Paid employee of Boehringer Ingelheim., Thomas Schindler Employee of: Employee of Boehringer Ingelheim Pharma, Henrik Finnern Employee of: Paid employee of Boehringer Ingelheim.

SAT0166 BIOMARKERS OF B-CELL DEPLETION AND RESPONSE IN A RANDOMIZED, CONTROLLED TRIAL OF OBINUTUZUMAB FOR PROLIFERATIVE LUPUS NEPHRITIS

Background:

Incomplete B-cell and plasmablast depletion, as measured using highly sensitive flow cytometry (HSFC), is associated with lower response rates following rituximab in SLE [1]. Enhanced B-cell depletion with the type II anti-CD20 mAb obinutuzumab resulted in increased renal responses in proliferative lupus nephritis (LN) in the NOBILITY trial (NCT02550652) and will be further evaluated in the Phase 3 REGENCY trial (NCT04221477).

Objectives:

To measure peripheral B-cells, B-cell subsets (naïve, memory and plasmablast) and B-cell activating factor (BAFF) levels and to assess associations between B-cell depletion and renal response in LN patients in a clinical trial of obinutuzumab.

Methods:

126 patients with active Class III/IV LN were randomized to obinutuzumab or placebo infusions in combination with mycophenolate and glucocorticoids. Peripheral B-cells were measured using a HSFC method with a lower limit of quantitation of 0.441 cells/μL. Serum levels of BAFF were evaluated using ELISA. Sustained depletion was defined by total B-cells below the limit of detection at both weeks 24 and 52. Renal response definitions from Phase 2 NOBILITY and Phase 3 REGENCY trials were used.

Results:

Obinutuzumab resulted in rapid and complete depletion of total B-cells, memory and naïve B-cells, and plasmablasts from peripheral blood, with 88% of obinutuzumab patients depleted to < 0.441 total B-cells/μL at week 2 (Figure). Mean serum BAFF increased from 4,585 pg/mL at baseline to 14,601 pg/mL at week 52 in the obinutuzumab group. Sustained B-cell depletion was achieved in 32/52 (62%) of patients with complete data and was associated with higher renal response rate at week 76 (Table), although patients who achieved sustained depletion also had lower baseline proteinuria and serum creatinine.

Conclusion:

Obinutuzumab, a type II anti-CD20 mAb, mediated rapid, complete and sustained depletion of peripheral B-cells and plasmablasts and large increases in serum BAFF. Similar to previous reports, sustained B-cell depletion was associated with increased renal response though there may be confounding factors. REGENCY is being conducted to further evaluate the therapeutic hypothesis with obinutuzumab in LN.

References:

[1]Md Yusof MY et al.Ann Rheum Dis. 2017;76:1829-36.

Table.

Data from NOBILITY at week 76 by depletion status at weeks 24 and 52

Definition of responseObinutuzumab sustained depletion (N = 32)aObinutuzumab detectable B-cells (N = 20)aPlacebo group detectable B-cells (N = 62)NOBILITY complete responseUPCR < 0.5, SCr ≤ ULN and not increased > 15% from baseline SCr, and < 10 RBC/hpf without casts50%**35%*18%NOBILITY overall responseCRR or ≥ 50% reduction in UPCRb with SCr not increased > 15% from baseline and urinary RBCs not increased > 50% from baseline66%***45%*29%REGENCY complete responseUPCR < 0.5, SCr ≤ ULN and not increased > 25% from baseline SCr69%**45%31%REGENCY overall responseCRR or ≥ 50% reduction in UPCRb with SCr not increased > 25% from baseline84%***55%50%

* P < 0.2 vs. placebo group.

** P < 0.05 vs. placebo group.

*** P < 0.001 vs. placebo group.

aEleven patients in the obinutuzumab group with insufficient data to determine depletion status were excluded.

b≥ 50% reduction in UPCR to a value < 1 (< 3 if the baseline UPCR was ≥ 3).

Acknowledgments :

This study was funded by F. Hoffmann-La Roche.

Disclosure of Interests: :

Edward Vital Grant/research support from: AstraZeneca, Roche/Genentech, and Sandoz, Consultant of: AstraZeneca, GSK, Roche/Genentech, and Sandoz, Speakers bureau: Becton Dickinson and GSK, Philippe Rémy: None declared, Luis Fernando Quintana Porras: None declared, Laurent Chiche: None declared, Dominique Chauveau: None declared, Richard Furie Grant/research support from: AstraZeneca, Biogen, Consultant of: AstraZeneca, Biogen, Thomas Schindler Employee of: F. Hoffmann-La Roche, Jay Garg Employee of: Genentech, Matthew D. Cascino Employee of: Genentech, Zahir Amoura Grant/research support from: GSK, Roche, Consultant of: GSK, Astra Zeneca, Amgen, Andrea Doria Consultant of: GSK, Pfizer, Abbvie, Novartis, Ely Lilly, Speakers bureau: UCB pharma, GSK, Pfizer, Janssen, Abbvie, Novartis, Ely Lilly, BMS, Cary Michael Donna Looney Employee of: Genentech, Dario Roccatello: None declared

Neurodevelopmental outcomes of extremely preterm infants in New South Wales and the Australian Capital Territory

AIM

This study aimed to provide updated information on gestation-specific neurodevelopmental outcomes of extremely to very preterm infants 23-28 weeks' gestation admitted to neonatal intensive care units (NICUs).

METHODS

This was a population-based retrospective cohort study of infants born between 23⁺⁰ and 28⁺⁶ weeks' gestation and admitted to a network of NICUs between 2007 and 2012 in a well-defined geographic area of New South Wales (NSW) and the Australian Capital Territory (ACT). Primary outcome was moderate to severe neurodevelopmental impairment.

RESULTS

Of 2287 infants admitted to NICUs, 1914 (83.7%) survived to discharge, and 1514 (79.8% = 1514/1897) were followed up. Moderate to severe neurodevelopmental impairment was 11% overall, and the incidence decreased with increasing gestational age (GA): 25, 23, 15, 13, 9 and 7% at 23, 24, 25, 26, 27 and 28 weeks, respectively. Male gender, major intraventricular haemorrhage, late-onset sepsis, chronic lung disease and post-natal corticosteroid therapy were found to be independently associated with increased risk of moderate to severe impairment. Compared with an incidence of 16% in the 1998-2004 cohort, there was a significant reduction in moderate to severe neurodevelopmental impairment in the current cohort (unadjusted odds ratio: 0.65, 95% confidence interval: 0.52-0.80).

CONCLUSIONS

We report the latest neurodevelopmental outcomes of extremely to very preterm infants in NSW and the ACT. Neurodevelopmental outcome rates based on GA alone may not provide the true estimate as these outcomes can vary based on the presence or absence of other relevant perinatal factors.

The Effect of Continuous Positive Airway Pressure on Cerebral and Splanchnic Oxygenation in Preterm Infants

BACKGROUND

Despite the known clinical benefits of continuous positive airway pressure (CPAP) to support preterm infants breathing, there are limited studies that have examined its effect on regional oxygenation.

OBJECTIVES

This study aimed to investigate how the application of CPAP affects cerebral and splanchnic tissue oxygenation in preterm infants.

METHODS

A pilot observational study was conducted in infants using near-infrared spectroscopy while off CPAP and on CPAP. Regional cerebral and splanchnic saturations and variability (coefficient of variability; CV) were evaluated.

RESULTS

Twenty-six infants (25-37 weeks gestational age at birth) were studied. The mean cerebral oxygenation did not differ with the application of CPAP (80 ± 4.2% without CPAP; 80 ± 1.9% with CPAP), but variability around the mean was less with CPAP (CV 5 vs. 2%, respectively). Mean cerebral fractional oxygen extraction (FOE) increased with CPAP from 0.13 ± 0.06 to 0.17 ± 0.04% (p = 0.002). Splanchnic oxygenation increased significantly from 66 ± 11.6 to 75 ± 9.1% with CPAP (p < 0.001) and also became more stable (CV 13 vs. 7%, respectively). Splanchnic FOE decreased with CPAP from 0.28 ± 0.13 to 0.22 ± 0.10% (p = 0.002).

CONCLUSION

The application of CPAP did not affect mean cerebral oxygenation in this group of preterm and term infants; however, it led to a significant increase in splanchnic oxygenation. These findings highlight the important role that respiratory support may play in maintaining adequate and stable oxygen delivery to vital organs.

Four-Dimensional Ultrasound for Evaluating Newborn Cardiac Output: A Pilot Study of Healthy Infants

BACKGROUND

There is currently no reliable non-invasive method of measuring cardiac output in neonatal intensive care. Spatiotemporal image correlation (STIC) is a novel four-dimensional (4D) ultrasound technique that was developed to assess the foetal heart, and it may be a useful way to assess neonatal haemodynamics.

OBJECTIVE

This study aimed to evaluate the feasibility and reproducibility of determining neonatal cardiac output using STIC ultrasound in newborn infants.

DESIGN

Infants were recruited opportunistically from a neonatal intensive care unit and then examined by 2 independent observers. STIC was used to obtain images of the heart. End-diastolic and end-systolic ventricular volumes were measured using virtual organ computer-aided analysis (VOCAL) and used to calculate cardiac output. Reproducibility was assessed with intraclass correlation coefficients (ICC) and agreement with Bland-Altman analysis.

RESULTS

Twenty-four clinically stable infants of 34-43 weeks corrected gestational age were assessed. Both observers successfully acquired 4D STIC volumes in all infants. Left ventricular output showed good reproducibility, with an intra-observer ICC of 0.86 (0.69-0.94) and inter-observer ICC of 0.87 (0.70-0.95). Right ventricular output also showed good reproducibility, with an intra-observer ICC of 0.88 (0.70-95) and inter-observer ICC of 0.84 (0.63-0.93).

CONCLUSIONS

Determining cardiac output using 4D STIC ultrasound is feasible and reproducible in well newborn infants. With further evaluation, this technique may provide valuable information about haemodynamic status in newborn infants requiring intensive care.

Particle-conserving dynamics on the single-particle level

We generalize the particle-conserving dynamics method of de las Heras et al. [J. Phys.: Condens. Matter 28, 244024 (2016)JCOMEL0953-898410.1088/0953-8984/28/24/244024] to binary mixtures and apply this to hard rods in one dimension. Considering the case of one species consisting of only one particle enables us to address the tagged-particle dynamics. The time-evolution of the species-labeled density profiles is compared to exact Brownian dynamics and (grand-canonical) dynamical density functional theory. The particle-conserving dynamics yields improved results over the dynamical density functional theory and well reproduces the simulation data at short and intermediate times. However, the neglect of a strict particle order (due to the fundamental statistical assumption of ergodicity) leads to errors at long times for our one-dimensional setup. The isolated study of that error makes clear the fundamental limitations of (adiabatic) density-based theoretical approaches when applied to systems of any dimension for which particle caging is a dominant physical mechanism.

Flexible sample cell for real-time GISAXS, GIWAXS and XRR: design and construction

Since the properties of functional materials are highly dependent on their specific structure, and since the structural changes, for example during crystallization, induced by coating and annealing processes are significant, the study of structure and its formation is of interest for fundamental and applied science. However, structure analysis is often limited to ex situ determination of final states due to the lack of specialized sample cells that enable real-time investigations. The lack of such cells is mainly due to their fairly complex design and geometrical restrictions defined by the beamline setups. To overcome this obstacle, an advanced sample cell has been designed and constructed; it combines automated doctor blading, solvent vapor annealing and sample hydration with real-time grazing-incidence wide- and small-angle scattering (GIWAXS/GISAXS) and X-ray reflectivity (XRR). The sample cell has limited spatial requirements and is therefore widely usable at beamlines and laboratory-scale instruments. The cell is fully automatized and remains portable, including the necessary electronics. In addition, the cell can be used by interested scientists in cooperation with the Institute for Crystallography and Structural Physics and is expandable with regard to optical secondary probes. Exemplary research studies are presented, in the form of coating of P3HT:PC₆₁PM thin films, solvent vapor annealing of DRCN5T:PC₇₁BM thin films, and hydration of supported phospholipid multilayers, to demonstrate the capabilities of the in situ cell.

Thomson scattering systems on C-2W field-reversed configuration plasma experiment

TAE Technologies' newly constructed C-2W experiment aims to improve the ion and electron temperatures in a sustained field-reversed configuration plasma. A suite of Thomson scattering systems has been designed and constructed for electron temperature and density profile measurements. The systems are designed for electron densities of 1 × 10¹² cm^-3 to 2 × 10¹⁴ cm^-3 and temperature ranges from 10 eV to 2 keV. The central system will provide profile measurements of T_e and n_e at 16 radial locations from r = -9 cm to r = 64 cm with a temporal resolution of 20 kHz for 4 pulses or 1 kHz for 30 pulses. The jet system will provide profile measurements of T_e and n_e at 5 radial locations in the open field region from r = -5 cm to r = 15 cm with a temporal resolution of 100 Hz. The central system and its components have been characterized, calibrated, installed, and commissioned. A maximum-likelihood algorithm has been applied for data processing and analysis.

Patterns of use of near-infrared spectroscopy in neonatal intensive care units: international usage survey

AIM

To assess uptake and applications of near-infrared spectroscopy (NIRS) by neonatal intensive care units (NICUs).

METHODS

A pre-piloted online questionnaire was distributed in May 2015 to 12 perinatal societies in Asia, Europe, Australasia, North America and Middle East for dissemination to NICUs. Questions surveyed demographics, NIRS research/clinical applications, usage frequency, training approaches and target infant populations.

RESULTS

In total, 255 responses from 235 NICUs were obtained. Of these, 85 (36%) owned a NIRS device. Australian and New Zealand NICUs were more likely to own NIRS technology than Asian (OR 1.12, 95% CI: 0.38-3.37) and North American (OR 2.63, 95% CI: 1.07-6.45) NICUs. A total of 69 (71%) used NIRS within clinical or mixed clinical-research settings, however routine reliance for management and prognostication was low (9% and 3%, respectively). Of those without NIRS technology, 96 (64%) had no acquisition intentions. The main limiting factors were controversial evidence on efficacy (59%) and financial considerations (50%). About 51% of respondents received in-house NIRS training and 32% had access to written guidelines.

CONCLUSION

There is considerable geographical variation in NIRS usage in NICUs that is, on the whole, limited by consumer perception of lack of evidence for its clinical utility. This knowledge gap should be addressed by future research.

Magnetic noninvasive acupuncture for infant comfort (MAGNIFIC) - a single-blinded randomised controlled pilot trial

AIM

To determine the safety and feasibility of auricular noninvasive magnetic acupuncture (MA) to decrease infant pain during heel pricks.

METHODS

Infants requiring heel pricks for blood collection were randomised to either MA (n = 21) or placebo (P) (n = 19) after parental informed consent. MA or placebo stickers were placed on both ears according to the Battlefield Protocol by an unblinded investigator and left on for 3 days. Pain was assessed with the Premature Infant Pain Profile (PIPP) by blinded clinicians.

RESULTS

Mean gestation (MA:34.1, P:34.4 weeks) and age of infants (MA:5.3, P:4.5 days) were similar as were mean (SD) pre (MA:1.7(1.4), P:2.1(1.9)) and post (MA:1.6(1.4), P: 2.1(1.7)) heel prick PIPP scores. PIPP scores were significantly lower in MA infants during heel pricks (MA:5.9(3.7), P: 8.3(4.7), p = 0.04). One-way ANCOVA modelling showed that MA was significantly associated with lower PIPP scores after controlling for analgesic use (p = 0.043). No differences in heart rate, oxygen saturation, analgesic use or adverse effects (e.g. local skin reactions) noted.

CONCLUSION

This pilot study shows that auricular MA is feasible in neonates and may reduce PIPP scores during heel pricks. Further study is required to determine the impact of MA on other painful or stressful conditions and on neurodevelopment.

Cerebral oxygenation as measured by near-infrared spectroscopy in neonatal intensive care: correlation with arterial oxygenation

AIM

To assess correlation between cerebral oxygenation (rScO₂ ), as measured by near-infrared spectroscopy (NIRS), and arterial oxygenation (PaO₂ ), as measured by arterial blood gases, in preterm neonates.

METHODS

Preterm neonates <37 weeks gestation with an indwelling arterial vascular catheter were recruited between April and August 2015 from the neonatal intensive care unit of the Royal Hospital for Women, Randwick NSW, Australia. The NIRS sensor was placed on the frontolateral aspect of the head prior to arterial gas sampling. NIRS, blood gas and clinical observation data were analysed using mixed linear modelling.

RESULTS

Twenty-two neonates between 24 and 31 weeks gestation (mean 27.6 weeks) were recruited, and 75 readings obtained. No significant correlation was identified between cerebral oxygenation (rScO₂ ) and arterial oxygenation (PaO₂ ) (p = 0.37). There was also no significant correlation between rScO₂ and clinically relevant parameters of SaO₂ (p = 0.06), SpO₂ (p = 0.44) and PaCO₂ (p = 0.79).

CONCLUSION

This study did not demonstrate any correlation between NIRS values and arterial oxygenation in clinically stable preterm infants. These results highlight some of the difficulties in clinical interpretation of NIRS values in neonatal intensive care, and further evaluation is needed to determine the applicability of NIRS to management of preterm infants.

Prediction of outcomes of extremely low gestational age newborns in Australia and New Zealand

OBJECTIVE

To determine the accuracy of the National Institute of Child Health and Human Development (NICHD) calculator in predicting death and neurodevelopmental impairment in Australian and New Zealand infants.

DESIGN

Population-based cohort study.

SETTING

Australia and New Zealand.

PATIENTS

Preterm infants 22-25 completed weeks gestation.

INTERVENTIONS

Comparison of NICHD calculator predicted rates of death and death or neurodevelopmental impairment, with actual rates recorded in the Australian and New Zealand Neonatal Network cohort.

MAIN OUTCOME MEASURES

Infant death and death or neurodevelopmental impairment rates.

RESULTS

A total of 714 infants were included in the study. Of these infants, 100 (14.0%) were <24 weeks, 389 (54.5%) male, 529 (74.1%) were singletons, 42 (5.9%) had intrauterine growth restriction, 563 (78.9%) received antenatal steroids and 625 (87.5 %) were born in a tertiary hospital. There were 288 deaths (40.3%), 75 infants (10.5%) with neurodevelopment impairment and 363 (50.8%) with death or neurodevelopmental impairment. The area under the curve (AUC) for prediction of death and the composite death or neurodevelopmental impairment by the NICHD calculator in our population was 0.65(95% CI 0.61 to 0.69) and 0.65 (95% CI 0.61 to 0.69), respectively. When stratified and compared with gestational age outcomes, the AUC did not change substantially for the outcomes investigated. The calculator was less accurate with outcome predictions at the extreme categories of predicted outcomes-underestimation of outcomes for those predicted to have the lowest risk (<20%) and overestimation for those in the highest risk category (>80%).

CONCLUSION

In our recent cohort of extremely preterm infants, the NICHD model does not accurately predict outcomes and is marginally better than gestational age based outcomes.

From evaporation-induced self-assembly to shear-induced alignment

The functionality of compact nanostructured thin films depends critically on the degree of order and hence on the underlying ordering mechanisms during film formation. For dip coating of rigid nanorods the counteracting mechanisms, evaporation-induced self-assembly (EISA) and shear-induced alignment (SIA) have recently been identified as competing ordering mechanisms. Here, we show how to achieve highly ordered and homogeneous thin films by controlling EISA and SIA in dip coating. Therefore we identify the influences of the process parameters including temperature, initial volume fraction and nanorod aspect ratio on evaporation-induced convective flow and externally applied shear forces and evaluate the resulting films. The impact of evaporation and shear can be distinguished by analysing film thickness, surface order and bulk order by careful in situ SAXS, Raman and SEM-based image analysis. For the first time we derive processing guidelines for the controlled application of EISA and SIA towards highly ordered thin nematic films.

The upgrade of the Thomson scattering system for measurement on the C-2/C-2U devices

The C-2/C-2U Thomson scattering system has been substantially upgraded during the latter phase of C-2/C-2U program. A Rayleigh channel has been added to each of the three polychromators of the C-2/C-2U Thomson scattering system. Onsite spectral calibration has been applied to avoid the issue of different channel responses at different spots on the photomultiplier tube surface. With the added Rayleigh channel, the absolute intensity response of the system is calibrated with Rayleigh scattering in argon gas from 0.1 to 4 Torr, where the Rayleigh scattering signal is comparable to the Thomson scattering signal at electron densities from 1 × 10¹³ to 4 × 10¹⁴ cm^-3. A new signal processing algorithm, using a maximum likelihood method and including detailed analysis of different noise contributions within the system, has been developed to obtain electron temperature and density profiles. The system setup, spectral and intensity calibration procedure and its outcome, data analysis, and the results of electron temperature/density profile measurements will be presented.

Dual wavelength imaging of a scrape-off layer in an advanced beam-driven field-reversed configuration

A dual wavelength imaging system has been developed and installed on C-2U to capture 2D images of a He jet in the Scrape-Off Layer (SOL) of an advanced beam-driven Field-Reversed Configuration (FRC) plasma. The system was designed to optically split two identical images and pass them through 1 nm FWHM filters. Dual wavelength images are focused adjacent on a large format CCD chip and recorded simultaneously with a time resolution down to 10 μs using a gated micro-channel plate. The relatively compact optical system images a 10 cm plasma region with a spatial resolution of 0.2 cm and can be used in a harsh environment with high electro-magnetic noise and high magnetic field. The dual wavelength imaging system provides 2D images of either electron density or temperature by observing spectral line pairs emitted by He jet atoms in the SOL. A large field of view, combined with good space and time resolution of the imaging system, allows visualization of macro-flows in the SOL. First 2D images of the electron density and temperature observed in the SOL of the C-2U FRC are presented.

Reference Ranges for Neonatal Basal Ganglia Perfusion as Measured by Fractional Moving Blood Volume

BACKGROUND

Regional changes in cerebral blood flow and perfusion are implicated in the pathogenesis of adverse neurological events that lead to death and severe disability in the newborn infant. The basal ganglia, in particular, are extremely sensitive to acute hypoxia in the perinatal period, but normal perfusion to this area is unknown.

OBJECTIVES

To establish a reference range for regional basal ganglia perfusion using fractional moving blood volume (FMBV) as an index.

METHODS

Head ultrasounds were performed on neonates from 25 to 41 weeks' gestation. Power Doppler images were obtained from a pre-specified coronal plane. FMBV was calculated offline after selecting the basal ganglia as a region of interest. The average of five calculations was considered to be representative of the regional perfusion for each neonate. The data were analysed, and a neonatal reference range was defined.

RESULTS

124 neonates were included in the study, and all had analysable data. The mean FMBV was 28.8% (±9.6) with a reference range defined as 10-48%. The mean FMBV for neonates <32 weeks', 32-35 weeks' and >35 weeks' gestation were 29.4% (±7.8), 29.2% (±11.0) and 27.4% (±9.7), respectively. Analysis of variance showed no significant difference between neonates based on gestation.

CONCLUSIONS

We have successfully used the index FMBV to define a reference range for perfusion in the basal ganglia. These data can be used as a reference for subsequent studies that evaluate basal ganglia perfusion in pathological conditions.

A Combined SAXS/SANS Study for the in Situ Characterization of Ligand Shells on Small Nanoparticles: The Case of ZnO

ZnO nanoparticles (NPs) have great potential for their use in, e.g., thin film solar cells due to their electro-optical properties adjustable on the nanoscale. Therefore, the production of well-defined NPs is of major interest. For a targeted production process, the knowledge of the stabilization layer of the NPs during and after their formation is of particular importance. For the study of the stabilizer layer of ZnO NPs prepared in a wet chemical synthesis from zinc acetate, only ex situ studies have been performed so far. An acetate layer bound to the surface of the dried NPs was found; however, an in situ study which addresses the stabilizing layer surrounding the NPs in a native dispersion was missing. By the combination of small angle scattering with neutrons and X-rays (SANS and SAXS) for the same sample, we are now able to observe the acetate shell in situ for the first time. In addition, the changes of this shell could be followed during the ripening process for different temperatures. With increasing size of the ZnO core (d(core)) the surrounding shell (d(shell)) becomes larger, and the acetate concentration within the shell is reduced. For all samples, the shell thickness was found to be larger than the maximum extension of an acetate molecule with acetate concentrations within the shell below 50 vol %. Thus, there is not a monolayer of acetate molecules that covers the NPs but rather a swollen shell of acetate ions. This shell is assumed to hinder the growth of the NPs to larger macrostructures. In addition, we found that the partition coefficient μ between acetate in the shell surrounding the NPs and the total amount of acetate in the solution is about 10% which is in good agreement with ex situ data determined by thermogravimetric analysis.

National Ignition Facility system alignment

The National Ignition Facility (NIF) is the world's largest optical instrument, comprising 192 37 cm square beams, each generating up to 9.6 kJ of 351 nm laser light in a 20 ns beam precisely tailored in time and spectrum. The Facility houses a massive (10 m diameter) target chamber within which the beams converge onto an ∼1 cm size target for the purpose of creating the conditions needed for deuterium/tritium nuclear fusion in a laboratory setting. A formidable challenge was building NIF to the precise requirements for beam propagation, commissioning the beam lines, and engineering systems to reliably and safely align 192 beams within the confines of a multihour shot cycle. Designing the facility to minimize drift and vibration, placing the optical components in their design locations, commissioning beam alignment, and performing precise system alignment are the key alignment accomplishments over the decade of work described herein. The design and positioning phases placed more than 3000 large (2.5 m×2 m×1 m) line-replaceable optics assemblies to within ±1 mm of design requirement. The commissioning and alignment phases validated clear apertures (no clipping) for all beam lines, and demonstrated automated laser alignment within 10 min and alignment to target chamber center within 44 min. Pointing validation system shots to flat gold-plated x-ray emitting targets showed NIF met its design requirement of ±50 μm rms beam pointing to target chamber. Finally, this paper describes the major alignment challenges faced by the NIF Project from inception to present, and how these challenges were met and solved by the NIF design and commissioning teams.

Myocardial perfusion assessment by use of system identification method in a one-compartment model

Cardiovascular magnetic resonance has been shown to provide high data quality for myocardial perfusion assessment. However, to analyze the perfusion data, some signal processing and modeling is needed to correct for motion related artifacts and limited spatial resolution. This study describes a method based on system identification, allowing, after a first step of image registration, to integrate and correct the partial volume effect in the myocardium perfusion quantification. This method is then applied to patients with coronary artery disease or hypertrophic obstructive cardiomyopathy.

[Palliative care in Germany]

The delivery of palliative care in Germany is still characterized by a wide-spread undersupply both for inpatients and outpatients. Nevertheless over the last 15 years progress has also been made in Germany, which is pleasing and which has directed professional and public attention increasingly to the situation of the incurably ill and dying. In the course of this development the first structures for specialized palliative care have been established. In particular the situation for inpatients in hospitals and hospices is pleasing, even if a satisfaction for total coverage is not yet reached. More seriously however is the demand for the outpatients. Financial means, which are steered so far only rudimentarily for palliative care, must be made sufficiently available, in order to be able to meet the demand with the help of appropriate structural offers. It is important to realize the needs of the incurably ill and dying and of their relatives and friends. Our society has to call attention to this subject and it should be placed on the healthpolitical agenda as a topic of the highest priority level. The current developments in the federation and in the federal states are encouraging and allowing hope that the delivery of palliative care for all who need it (and not only the ill) will improve further in the coming years.

[Appropriate uptake period for myocardial PET imaging with 18F-FDG after oral glucose loading]

AIM

Identification of a rationale for the appropriate uptake period for myocardial (18)F-FDG-PET imaging of patients with and without diabetes mellitus.

METHODS

In a subset of 27 patients, static 2D-PET examination was performed of patients with chronic coronary artery disease and known myocardial infarction. The patients fasted (at least 4 h) before examination. (18)F-FDG (330 +/- 20 MBq) was injected intravenously. The image quality was semiquantitativly determined by ROI-analysis and the myocardium-to-blood pool activity ratio (M/B) was calculated. I.) Scans 30, 60, and 90 min p. i. of 10 non-diabetic patients (60 g oral glucose loading one hour before FDG-injection, low-dose intravenous insulin bolus if necessary). II.) Scans 30, 60, and 90 min p. i. of 10 patients with known non-insulin dependent diabetes (20 g glucose, insulin bolus). III.) Scans 90 min p. i. of 7 patients with known non-insulin dependent diabetes and elevated fasting serum glucose level (140-200 mg/dl; insulin bolus, no glucose).

RESULTS

I.) The M/B ratio significantly increases in nondiabetic patients with the uptake time (30 min 1.95 +/- 0.20; 60 min 2.96 +/- 0.36; 90 min 3.78 +/- 0.43). II.) In patients with non-insulin dependent diabetes the M/B ratio also significantly increases with uptake time. Compared to non-diabetic patients group II reached smaller M/B values (30 min 1.56 +/- 0.10; 60 min 2.15 +/- 0.14; 90 min 2.71 +/- 0.19). III.) In the group of patients with elevated fasting serum glucose level (who only got insulin but no glucose loading) the M/B activity ratio 90 min p. i. was clearly inferior compared with diabetic patients after oral glucose loading and insulin administration (M/B 2.71 +/- 0.19 versus 2.16 +/- 0.07).

CONCLUSIONS

In static myocardial viability PET studies with (18)F-FDG an uptake time of 90 min yields image quality superior to that obtained after shorter uptake time.

Optimaler Akquisitionszeitpunkt für die Herz-PET mit 18F-FDG nach oraler Glukosebelastung

Aim: Identification of a rationale for the appropriate uptake period for myocardial 18F-FDG-PET imaging of patients with and without diabetes mellitus. Methods: In a subset of 27 patients, static 2D-PET examination was performed of patients with chronic coronary artery disease and known myocardial infarction. The patients fasted (at least 4 h) before examination. 18F-FDG (330 ± 20 MBq) was injected intravenously. The image quality was semiquantitativly determined by ROI-analysis and the myocardium-to-blood pool activity ratio (M/B) was calculated. I.) Scans 30, 60, and 90 min p. i. of 10 non-diabetic patients (60 g oral glucose loading one hour before FDG-injection, low-dose intravenous insulin bolus if necessary). II.) Scans 30, 60, and 90 min p. i. of 10 patients with known non-insulin dependent diabetes (20 g glucose, insulin bolus). III.) Scans 90 min p. i. of 7 patients with known non-insulin dependent diabetes and elevated fasting serum glucose level (140-200 mg/dl; insulin bolus, no glucose). Results: I.) The M/B ratio significantly increases in non-diabetic patients with the uptake time (30 min 1.95 ± 0.20; 60 min 2.96 ± 0.36; 90 min 3.78 ± 0.43). II.) In patients with non-insulin dependent diabetes the M/B ratio also significantly increases with uptake time. Compared to non-diabetic patients group II reached smaller M/B values (30 min 1.56 ± 0.10; 60 min 2.15 ± 0.14; 90 min 2.71 ± 0.19). III.) In the group of patients with elevated fasting serum glucose level (who only got insulin but no glucose loading) the M/B activity ratio 90 min p. i. was clearly inferior compared with diabetic patients after oral glucose loading and insulin administration (M/B 2.71 ± 0.19 versus 2.16 ± 0.07). Conclusions: In static myocardial viability PET studies with 18F-FDG an uptake time of 90 min yields image quality superior to that obtained after shorter uptake time.

Phosphorylation and structure-based functional studies reveal a positive and a negative role for the activation loop of the c-Abl tyrosine kinase

c-Abl is a nuclear and cytoplasmic tyrosine kinase involved in a variety of cellular growth and differentiation processes. In contrast to its oncogenic counterparts, like BCR-Abl, c-Abl is not constitutively tyrosine phosphorylated and its catalytic activity is very low. Here we report tyrosine phosphorylation of endogenous c-Abl and a concomitant increase in catalytic activity. Using Abl -/- cells reconstituted with mutated c-Abl forms, we show that phosphorylation and activity depend on Tyr412 in the activation loop. Tyr412 is also required for stimulation by PDGF or by cotransfection of active Src. Phosphorylation of Tyr412 can occur autocatalytically by a trans-mechanism and cause activation of otherwise inactive c-Abl, suggesting a positive feedback loop on c-Abl activity. In the recent structure of the Abl catalytic domain bound to the STI-571 inhibitor, unphosphorylated Tyr412 in the activation loop points inward and appears to interfere with catalysis. We mutated residues involved in stabilizing this inhibited form of the activation loop and in positioning Tyr412. These mutations resulted in tyrosine phosphorylation and activation of c-Abl, as if relieving c-Abl from inhibition. Tyr412 is therefore necessary both for activity and for regulation of c-Abl, by stabilizing the inactive or the active conformation of the enzyme in a phosphorylation-dependent manner.

DcAGP1, a secreted arabinogalactan protein, is related to a family of basic proline-rich proteins

A cDNA corresponding to the core protein of an immunoaffinity-purified arabinogalactan protein (AGP) secreted aucus carota (carrot) cells in liquid culture was isolated. This cDNA, DcAGP1, encodes a new class of non-classical' AGP with strong similarity to a family of basic proline-rich proteins. The protein is rich in proline (17%), alanine (10%) and lysine (11%) and contains four distinct domains: a signal peptide, a proline-rich domain, a histidine-rich basic domain and a cysteine-containing 'PAC' domain that is found in a range of other cell wall proteins. The protein contains several sequence motifs found in otherwise unrelated cell wall proteins, but also displays some unique features. Northern blot analyses show that while the DcAGP1 transcript is abundant in the suspension-culture cells from which the AGP was obtained; in carrot seedlings the gene is only expressed at low levels in the roots and it is neither wound- nor stress-inducible. Furthermore, northern and western blot analyses demonstrate that the core polypeptide of DcAGP1 is differentially glycosylated in two different carrot suspension cultures. The unusual features of the protein sequence suggest that the DcAGP1 protein is a member of a family of basic proline-rich proteins defined by the C-terminal PAC domain, and the possible function(s) of the DcAGP1 protein is considered in the light of current views on AGP structure and function.

Structural mechanism for STI-571 inhibition of abelson tyrosine kinase

The inadvertent activation of the Abelson tyrosine kinase (Abl) causes chronic myelogenous leukemia (CML). A small-molecule inhibitor of Abl (STI-571) is effective in the treatment of CML. We report the crystal structure of the catalytic domain of Abl, complexed to a variant of STI-571. Critical to the binding of STI-571 is the adoption by the kinase of an inactive conformation, in which a centrally located "activation loop" is not phosphorylated. The conformation of this loop is distinct from that in active protein kinases, as well as in the inactive form of the closely related Src kinases. These results suggest that compounds that exploit the distinctive inactivation mechanisms of individual protein kinases can achieve both high affinity and high specificity.

Reciprocal regulation of Hck activity by phosphorylation of Tyr(527) and Tyr(416). Effect of introducing a high affinity intramolecular SH2 ligand

The Src family tyrosine kinase Hck possesses two phosphorylation sites, Tyr(527) and Tyr(416), that affect the catalytic activity in opposite ways. When phosphorylated, Tyr(527) and residues C-terminal to it are involved in an inhibitory intramolecular interaction with the SH2 domain. However, this sequence does not conform to the sequence of the high affinity SH2 ligand, pYEEI. We mutated this sequence to YEEI and show that this mutant form of Hck cannot be activated by exogenous SH2 ligands. The SH3 domain of Hck is also involved in an inhibitory interaction with the catalytic domain. The SH3 ligand Nef binds to and activates YEEI-Hck mutant in a similar manner to wild-type Hck, indicating that disrupting the SH3 interaction overrides the strengthened SH2 interaction. The other phosphorylation site, Tyr(416), is the autophosphorylation site in the activation loop. Phosphorylation of Tyr(416) is required for Hck activation. We mutated this residue to alanine and characterized its catalytic activity. The Y416A mutant shows a higher K(m) value for peptide and a lower V(max) than autophosphorylated wild-type Hck. We also present evidence for cross-talk between the activation loop and the intramolecular binding of the SH2 and SH3 domains.

Vitamin C improves endothelial function of epicardial coronary arteries in patients with hypercholesterolaemia or essential hypertension--assessed by cold pressor testing

AIMS

There is evidence that formation of free radicals increases in patients with hypertension or hypercholesterolaemia, which may contribute to endothelial dysfunction of epicardial coronary arteries due to inactivation of the vasodilator NO. The present study was designed to test whether the abnormal constriction of epicardial coronary arteries due to sympathetic stimulation by the cold pressor test in patients with essential hypertension or hypercholesterolaemia could be reversed by administration of the antioxidant vitamin C.

METHODS AND RESULTS

In 28 patients without relevant coronary artery stenosis the cold pressor test was performed before and after a 3 g infusion of vitamin C. In five normal controls the cold pressor test led to a similar increase in luminal area before and after vitamin C (3.7+/-1.3% and 1.9+/-0.8%, ns vs before vitamin C). In nine hypercholesterolaemic patients the cold pressor test led to a -14.1+/-2.8% reduction in cross-sectional area before vitamin C. This constriction was significantly improved after vitamin C to -7.6%+/-2.0, P=0.027 vs before vitamin C. In nine hypertensive patients, the cold pressor test led to a -17.1+/-3.2% decrease in cross-sectional area before vitamin C, which was improved to -7.1+/-3.1 after vitamin C, P=0.004 vs before vitamin C. This increase in luminal area was significant in each group in comparison with normal controls (each P<0.05). Administration of saline (placebo group, five patients) had no significant effect on cold pressor test-induced constriction (-6.9+/-3.9% before and -6. 8+/-3.7% after saline).

CONCLUSION

The antioxidant vitamin C reverses cold pressor test-induced vasoconstriction of epicardial coronary arteries in patients with hypertension or hypercholesterolaemia. Our data suggest that enhanced oxidative stress contributes to impaired endothelial function in this patient population.

Crystal structure of Hck in complex with a Src family-selective tyrosine kinase inhibitor

The crystal structure of the autoinhibited form of Hck has been determined at 2.0 A resolution, in complex with a specific pyrazolo pyrimidine-type inhibitor, PP1. The activation segment, a key regulatory component of the catalytic domain, is unphosphorylated and is visualized in its entirety. Tyr-416, the site of activating autophosphorylation in the Src family kinases, is positioned such that access to the catalytic machinery is blocked. PP1 is bound at the ATP-binding site of the kinase, and a methylphenyl group on PP1 is inserted into an adjacent hydrophobic pocket. The enlargement of this pocket in autoinhibited Src kinases suggests a route toward the development of inhibitors that are specific for the inactive forms of these proteins.

Microsecond folding of the cold shock protein measured by a pressure-jump technique

A pressure-jump apparatus was employed in investigating the kinetics of protein unfolding and refolding. In the reaction cell, the pressure can be increased or decreased by 100-160 bar within 50-100 microseconds and then held constant. Thus, unfolding and refolding reactions in the time range from 70 microseconds to 70 s can be followed with this technique. Measurements are possible in the transition regions of thermally or denaturant-induced folding in a wide range of temperatures and solvent conditions. We used this pressure-jump method to determine the temperature dependence of the rate constants of unfolding and refolding of the cold shock protein of Bacillus subtilis and of three variants thereof with Phe --> Ala substitutions in the central beta-sheet region. For all variants, the change in heat capacity occurred in refolding between the unfolded and activated states, suggesting that the overall native-like character of the activated state of folding was not changed by the deletion of individual Phe side chains. The Phe27Ala mutation affected the rate of unfolding only; the Phe15Ala and Phe17Ala mutations changed the kinetics of both unfolding and refolding. Although the activated state of folding of the cold shock protein is overall native-like, individual side chains are still in a non-native environment.